Aim: The aim of this study was to evaluate the effect of adjustments to a compression stocking on reductions in leg volume during walking in patients with lymphedema.Method: Fourteen women and three men suffering from leg lymphedema with ages between 21 and 68 years old (mean 45.68 years) were randomly enrolled in this study. Evaluations were made by volumetry before and after each session of controlled walking. Patients were subjected to three one-hour sessions of walking slowly on the flat ground monitored by a professional. For the first session, the patients used a well-adjusted cotton-polyester compression stocking, for the second they used a badly adjusted compression stocking made of the same fabric, and for the third, no compression garment was used. The Kruskal-Wallis test was used for statistical analysis.Results: On comparing the volume before and after walking for one hour with the well-adjusted cotton-polyester compression stocking, there was a mean reduction of 46.2 mL ± 66.95 mL  in the volume of the lymphedema. In the one-hour session of walking without any compression, the volume of the leg increased by 74.4 mL ± 99.75 mL . On walking with the compression stocking badly adjusted, there was a mean increase in the volume of 31.6 mL ± 46.9 mL .Conclusion: Walking is a type of muscle activity that can be transformed into a type of daily exercise when you are guided by how it is going to be performed. The exercise, in this study specifically, walking, with a strict control of speed and time of realization using a compression mechanism is well adjusted to the volume of the limb and surely effective in reducing edema. Lymphedema affects many populations, there is no cure, and there are few therapeutic prospects involving, in general, the private sector. This situation is aggravated in low-income countries where a lack of government resources and specialized health workers has led to the marginalization of the disease .There is no consensus on a single therapy to treat lymphedema; however, manual lymph drainage , compres Walking is a type of muscle activity that can be transformed into a type of daily exercise when you are guided by how it is going to be performed. A pilot study of the Godoy & Godoy poster presented at the 24th World Congress of Lymphology, Italy, September 2013, suggested that when compared the volume before and after walking for one hour with the well-adjusted cotton-polyester compression stocking show reductions in the volume of leg lymphedema. The aim of this study was to evaluate the effect of adjustments to a compression stocking on reductions in leg volume during walking in patients with lymphedema.MethodSeventeen patients presented with a diagnosis of lower limb bilateral below the knee, congenital primary bilateral, and early primary lymphedema. All initial diagnoses were performed more than five years ago and patients were selected in a cross-over study where all patients already participated in the rehabilitation group and were selected on a first-come basis at the Clinica Godoy-São José do Rio Preto-Brazil. The group was made up of 14 women and three men with ages between 21 and 68 years and a mean age of 45.68 years. The inclusion criterion was the presence of any type of Grade II leg lymphedema diagnosed clinically or by lymphoscintigraphy. The exclusion criteria were lymphedema associated with osteoarticular problems and active infections identified during the initial evaluation and other clinically diagnosed causes of edema. An assessment was made by water-displacement volumetry (following the principle of Archimedes) before and immediately after each session of walking utilizing a measuring container especially developed for this examination. All patients were submitted to three evaluations using mechanism compression made grosgrain fabric, custom made according to the size of the limb, use eyelets to allow a certain amount of adjustment directly by the patient. For one session the patients walked slowly for one hour using a well-adjusted cotton-polyester (grosgrain) compression stocking, without any ‘space’ between the compression stocking and the skin, for the second they used a badly adjusted cotton-polyester compression stocking (that was loose and so there was ‘space’ between it and the skin), and for the third, no cotton-polyester compression stocking was used. The stockings were tailor-made for each patient. The compression device used in this study was a stocking made from a cotton-polyester fabric called grosgrain. Grosgrain is a fabric that has important features including a low stretch and yet ribbed structure. The ribbed aspect improves the fit around the leg compared to other textiles. Additionally, the fabric stretches < 50% of its size along the direction of the ribs but stretches more across the ribs thereby facilitating joint flexibility without losing compression. The participants performed the sessions in no specific order (cross-over). The patients always walked on flat ground and in the morning between 8:00 and 9:00 o’clock and were monitored by a physiotherapist who controlled the speed at which they walked. The speed of walking was according to the physical condition of each patient. The patients were asked to walk at their normal speed without stopping. The Kruskal-Wallis test, Dwass-Steel-Critchlow-Fligner, and paired t-tests were used for statistical analysis with an alpha error of 5% being considered acceptable. Before starting the study, all participants signed informed consent forms. This study was approved by the Research Ethics Committee of the Medicine School in São José do Rio Preto (#374/2009).There was a mean reduction of 46.2 mL  in volume while walking with a well-adjusted compression garment. The volume increased by an average of 74.5 mL  while walking without any compression. Although insignificant, there was a mean increase in the volume of 31.6 mL  during the walking session using a badly adjusted cotton-polyester compression garment. Figure This study shows that walking is a type of muscle activity that can be transformed into a type of daily exercise when you are guided by how it is going to be performed. When we associated mechanism compression a synergistic effect occurs in reducing the volume of lymphedema, that is, the association of two mechanisms enhances the reduction in the volume of edema. The compression garment used in this study is made from a cotton-polyester fabric called grosgrain; this fabric is perfect to exert low-stretch compression of up to 50% . While wThis assessment is educationally important for patients and even for professionals, as it proves the importance of careful adjustments to maximize the result. The necessity of constant adjustments in nonelastic and low-stretch compression lies in the mechanism of action; muscle activity generates varying working pressures on the interface between the skin and the compression device. Thus, the hypothesis is that the reduction in the size of the leg leads to a decrease in the effectiveness of the changes in working pressure to provide reductions until at one point this pressure no longer exists. From this moment, further losses in volume will not occur and the effectiveness of the treatment is lost; this explains the need for continuous adjustments of the compression garment.These stockings are different from elastic stockings because the latter have both resting and working therapeutic pressures . Hence, Another aspect to be considered is that when muscles work, they require a higher blood flow and therefore greater capillary filtration and an increased need for lymphovenous drainage; a reduction in edema of the limb depends on this balance. If muscle activity requires a larger amount of blood than the capacity of lymphovenous drainage, the edema will increase.This study shows that when patients with lymphedema walked without any type of compression device, the lymphedema worsened; when the patients walked with a badly adjusted compression device, the edema increased slightly, but when the compression was well adjusted, the edema reduced. In this study, the muscle activity was controlled and the only variable that changed was the type of compression. However, the type of muscular activity must be controlled to assess the balance between capillary filtration and lymphovenous drainage.Thus in the treatment of lymphedema, it is essential to maintain the trophism and the integrity of the venous return including the muscle propulsion and aspiration pumps . FailureElastic stockings on patients with chronic venous disease may also help to reduce the size of the legs while walking . HoweverOne suggestion is the development of devices to evaluate the resting and working pressures that are routinely experienced with compression therapy. Thus, it will be possible to identify the best time to replace stockings by checking that they are well adjusted and to maintain the efficacy of compression therapy. The limitation of the current study is that it could have been carried out in other types of lymphedema as a secondary, thus we would be able to evaluate how this type of exercise behaves in this type of lymphedema. However, this study is already an objective of the researchers.Walking is a type of muscle activity that can be transformed into a type of daily exercise when you are guided by how it is going to be performed. The exercise, in this study specifically, walking, with a strict control of speed and time of realization using a compression mechanism is well adjusted to the volume of the limb and surely effective in reducing edema.


The current method of digitally designing dental prostheses mainly focuses on intra‐oral soft and hard tissues, although the harmony of the facial soft tissue and the prosthesis is crucial, especially for esthetics. Here, we introduce a new method of digitally designing dental prostheses using a new device that generates a virtual patient and incorporates facial features into the prosthetic design.A new extra‐oral scan body for facial scanning was designed and developed. A definitive edentulous maxilla implant cast with four extra‐oral scan bodies  was placed in the mouth of a dental mannequin. The dental mannequin was scanned with and without the extra‐oral scan bodies. For reference data, an impression of the maxilla was taken and scanned with a laboratory scanner. By superimposing each acquired data, a virtual patient was generated, and the spatial location of the abutments relative to the face was clarified. Identifying the accurate location of the abutments enabled to design face‐driven dental prosthesis.Based on the color‐coded deviation map created by the data acquired from conventional and extra‐oral scan bodies, the divergence of the two data was mostly within 0.1 mm, which proves that the extra‐oral scan bodies were as accurate as conventional scan bodies. Therefore, the facial scan data and the scan data of the oral cavity were successfully superimposed, which allowed to generate a virtual patient to design face‐driven prosthesis.The new method is effective for designing high‐quality face‐driven prostheses, especially when treating a patient with a full‐arch implant‐fixed prosthesis. To make full use of this 3D information, a digital approach can be used to examine the facial anatomical features from multiple angles. Some methods have already incorporated 3D data of a patient's facial anatomical features to generate a “virtual patient” for 3D clinical evaluation, as well as to design and fabricate dental prostheses  file format to be used in CAD software. After, the design of the dental prosthesis is altered and confirmed, the CAD data are converted into an STL file format and sent to the milling machine to fabricate the dental prosthesis .Information on the location of the abutment and intra‐oral hard and soft tissues will be obtained by scanning the stone cast using a desktop scanner (“Data C").By superimposing Data A and B, the spatial location of the abutment relative to the face is clarified (“Data D").By superimposing Data B and C, the location of the abutment within the oral cavity will be clarified (“Data E"). With Data D and E superimposed based on the abutments, the digital wax‐up of the prosthesis designed with CAD software can be accurately placed inside the virtual patient's mouth. This new system is available for any patient treated with dental implants. The steps and the simplified flow chart are shown in Figure The majority of the steps in the new system are the same as those in the conventional system, with some exceptions. The steps are as follows:By utilizing these data and following the steps above, a virtual patient is generated, allowing the clinician and dental technician to simulate and design the dental prosthesis using data from the intra‐oral soft and hard tissues and facial soft tissue to evaluate how the dental prosthesis affects the facial features.2.2Simple geometrical shapes were selected when designing the new device to enable the handheld 3D optical scanner to scan the structure of the extra‐oral scan body, thereby decreasing the probability of acquiring distorted digital data  was selected for manufacturing the extra‐oral scan body given its physical and mechanical properties, such as excellent flexural fatigue resistance and sufficient stiffness for the structural rigidity of the structure  using a laboratory scanner . The scan data acquired by the laboratory and handheld scanners were termed “reference data” and “scan data,” respectively. The process of identifying the location of the dental abutment is shown in Figure 3In this new system of designing and fabricating implant‐fixed dental prostheses, the dental implant abutment is used as a landmark to superimpose the digital wax‐up of the prosthesis and 3D facial data. The abutment was used because the CAD software was unable to export the STL file format of the implant body. However, the CAD implant abutment data were exportable in the STL file format; thus, the abutment was selected as a landmark for superimposition. Although a virtual patient can be generated, the accuracy of extra‐oral scan bodies should be high in order to be useful. To verify the accuracy of the new device, a color‐coded deviation map of the superimposed abutments was created by using the data acquired from conventional and facial scan bodies Figure . Most ofThe mannequin used in this trial may not have been sufficient to prove that the new device and the facial features enable the design of highly esthetic dental prostheses since it lacks several main extra‐oral features. However, as it could generate a virtual patient and design a full‐arch implant‐fixed prosthesis from the limited extra‐oral information, it has great potential in creating a highly esthetic dental prosthesis. Further confirmation is needed with future studies.3.1Although the scan body is important for identifying the dental implant location, the scanner employed to acquire digital 3D information of facial soft tissue is another important factor that influences accuracy (Eiríksson et al., The proficiency of the operator is also an important factor. IOSs are not affected by the operator (Arcuri et al., In this study, a mannequin was used to confirm that the new device could be used to create a virtual patient for planning and designing prostheses. However, when utilizing this new device in clinical situations, one should consider that, unlike the mannequin, an actual patient could make slight movements during acquisition of facial data, which would result in motion artifacts. The motion artifacts could be a challenge in actual clinical practice. Though we have not yet determined how motion artifacts will affect the data, it could be expected that it would cause adverse effects. For example, slight change of the position of the abutment might occur compared to the actual position of the abutment. Therefore, in order to avoid consequences caused by motion artifacts, such as redesigning and remanufacturing of the final prosthesis, it is highly recommended that conducting a try‐in based on the acquired data should be done first to confirm that the design is functionally and esthetically fine before moving on to final processing. In order to clarify the effect of motion artifacts on the acquired data, further confirmation should be conducted with actual patients.3.2Reports on IOS accuracy indicate that deviations in the acquired data become more distinctive with a certain distance between implants (Amin et al., The accuracy of the virtual patient affects treatment outcomes because the dental prosthesis is fabricated based on CAD data. Several methods of generating virtual patients have been introduced and reported in past studies. According to Joda et al. , three d4This article describes a new method of generating a virtual patient using a new device. This newly designed extra‐oral scan body could enable clinicians to design and fabricate face‐driven and highly esthetic dental prostheses using digital technology. The new digital workflow is low‐cost and effective for designing high‐quality face‐driven prosthetics, especially when designing and fabricating full‐arch fixed prostheses.The authors declare that they have no conflict of interest.Naruto Otawa contributed to conception, design, and critically revised the manuscript; Tsukasa Aoki contributed to the acquisition and analysis of the data and led the writing; Tomoki Sumida contributed to acquisition, analysis of the data, and critically revised the manuscript; Tsukasa Yanagi contributed to the acquisition of the data; Hirofumi Kido contributed to conception, summarizing and analyzing the data, and critically revised the manuscript.


It is shown that both the maximum value of liquid penetration into the capillary and bubble growth time are affected by perturbations to the water hardness. The time it takes for the bubble to depart the capillary was estimated using the following nonlinear data analysis methods: time delay (τ), attractor reconstructions, correlation dimension (D), and largest Lyapunov exponent (λ). All estimates demonstrate that the pressure fluctuations in the c–c aqueous solutions and extent of liquid solution penetration into the capillary during the time between subsequent bubble departures behave chaotically. Furthermore, this work demonstrates that the dynamics of bubble formation along with the bubble waiting time are very sensitive to small perturbation in the physical properties of the liquid, and this sensitivity has a significant effect on the observed chaotic behaviour.The influence of small changes to water hardness on the nonlinear behaviour of liquid penetration into a capillary and the resulting air pressure fluctuations during air bubble formation are examined in this paper. Experiments were undertaken in which bubbles were generated both in water having a surface tensile force of  Because the chaotic nature of the gas bubble departure process is influenced by many factors, some presently unknown, these studies continue. Moreover, understanding the dynamics of gas bubble flow in liquids is important for the chemical process and pharmaceutical industries, in which applications ranging from water aeration to various mass transfer operations rely on the careful control of such flow8. Also, a better understanding of the flow of methane gas bubbles in underwater environments is important for quantifying the contribution that methane release to the atmosphere has on the global balance of greenhouse gases10. In all of these applications, chaotic behaviour is observed, and water hardness is suspected to influence this chaotic behaviour. For these reasons, the focus of this paper will be to investigate the effects that small changes to water hardness have on the chaotic behaviour of bubble flow in liquid water.The process of gas bubble formation in liquids has been investigated since the 1950s. These studies included investigations into bubble formation in bubble-beds and foam beds16, it can be concluded that two groups of phenomena are responsible for the occurrence of chaotic bubble departures: the particular dynamics of the bubble flow in the liquid as well as the hydrodynamics of liquid flow around the capillary18 and the erratic changes of pressure in the gas supply system that accompany this flow21; these phenomena are associated with the nonlinear dynamics of the capillary filling process. These dynamics are sensitive to the physical and chemical properties of the two-phase system, notably the viscosity and surface tension, as well as to the container geometry, and have been previously investigated21. Nevertheless, the influence of water hardness on the nonlinear behaviour of the capillary filling process into the capillary, a topic with which the present paper is concerned, has yet to be fully investigated.From the many investigations into the chaotic nature of bubble departurewaiting time. The time between when a vapour bubble starts to form at the tip of the capillary and when it reaches a size at which it physically detaches from the capillary tip is called bubble growth time.The following terminology will be used throughout this paper. The time after which liquid has filled the capillary and before the onset of bubble formation is called the 22, the buoyancy force23, the surface tension force24, a force associated with added bubble mass25, and a force derived from the changing momentum of the gas within the bubble26. Secondly, the waiting time depends on pressure changes in the gas supply and certain boundary conditions such as the gas chamber volume27, the height of the liquid over the capillary, the length of the capillary21 and surface tension27. Thirdly, an increase in chamber volume causes an increase in the bubble departure time17. Fourthly, a decrease of the liquid height over the capillary causes both the bubble growth time and the waiting time to decrease17. Fifthly, an increase in the increase in height of the liquid above the capillary caused an increase in the depth and velocity of liquid penetration into the capillary17. Lastly, an increase in liquid viscosity causes a corresponding increase in the bubble growth time but does not affect the bubble waiting time17. In all, the influence of small water hardness perturbations on liquid penetration into a nozzle and its impact on chaotic bubble departures has yet to be fully investigated. Those investigations can, for example, be helpful in achieving a better understanding of gas bubble departures in natural water reservoirs, where water hardness can significantly affect methane bubble formation in and subsequent emission from these reservoirs.Previous work has demonstrated the following. Firstly, the bubble growth time depends on the forces acting on the growing bubble; these forces include the drag forceσ = 72 mN/m) and in an aqueous solution of calcium carbonate  were investigated to determine the effects of small modifications of water hardness on the bubble dynamics. The temperature of both liquids was equal to 20 °C. The depth of liquid penetration into the capillary was filmed with a high-speed camera, and pressure fluctuations in the gas supply system were measured for different air volume flow rates. Bubble departure periodicity was estimated using the following non-linear data analysis methods: time delay (τ), attractor reconstructions, correlation dimension (D) and largest Lyapunov exponent (λ). In “In the present paper, the liquid penetration into the glass capillary with an internal diameter of 1 mm was studied. In the experiment, bubble generation in both tap water . Time series of the air pressure changes were recorded by using a Data Translation DT9804 data acquisition system. The frequency of sampling was equal to 1 kHz, a maximum sampling frequency for the air pressure sensors used. The liquid movement inside the capillary was recorded with a high-speed camera—Phantom v1610. Videos were recorded with a speed of 5000 fps in the grayscale. Resolution of the video frames was 512 × 768 pixels, and the duration of each video was 15 s. In Fig. Videos were divided into frames, which were used to determine time series of the liquid movement inside the capillary. The depth of the liquid penetration into the capillary was measured by the program, which counted the number of pixels that showed the presence of water in the capillary. Pixels with brightness higher than a certain threshold indicated the presence of air in the capillary; otherwise, the pixel brightness indicated the presence of water in the capillary. Some time series representing the depth of liquid flow into the capillary and air pressure fluctuations are shown Fig. I and II. The bubble growth stage is marked using symbol I. During this stage, the depth of the liquid penetration is equal to 0  methodq ≤ 0.044 l/min. The accuracy of the measurements was estimated by the following formula:xmean is the mean value of all samples. The accuracy of measurements of the depth of liquid penetration as a function of air volume flow rate varied from 0.14 to 5.61% for water and from 0.41 to 3.05% for calcium carbonate in aqueous solutions. Overall, an increase of air volume flow rate caused the maximum depth of liquid penetration inside the glass capillary to decrease, a result that can be expected from the principles of fluid mechanics and discussed in “The results show that the influence of surface tension on bubble departure frequency is insignificant. One notices, however, that the surface tension has a marked influence on the depth of liquid penetration into the capillary, as can be expected. The ranges of air volume flow rates, in which the liquid penetration inside the capillary occurred, varied depending on the hardness of the liquid water. When bubbles were generated in water, liquid penetration inside the capillary was observed for air volume flow rates in the range of 0.005–0.038 l/min. The largest range of air volume flow rate at which liquid movement occurs in calcium carbonate in aqueous solutions was 0.005 l/min ≤ p vs. air volume flow rate are shown in Fig. Maximum and minimum values of pressure in the gas supply system and Δmax and higher values of pmin observed and discussed in “At the maximum air pressure, mentclass2pt{minimIn Fig. Waiting time and bubble growth time were estimated using the time series of liquid movement inside the capillary and compared with times estimated using time series of pressure changes in the gas supply system , the velocity with which the liquid penetrates into the capillary (vlp), and the dependence of the bubble diameter (db) growth vs. the air volume flow rate are shown.In Fig. Measurement accuracies of bubble diameter growth ranged from 0.38 to 0.61% for water and from 0.58 to 1.00% for calcium carbonate in aqueous solutions; those of the exit velocity of liquid vapour from a capillary varied from 0.26 to 6.50% for water and from 0.44 to 6.06% for calcium carbonate in aqueous solutions. The accuracy of measurements of the liquid penetration into the capillary varied from 0.07 to 1.35% for water and from 0.73 to 2.94% for calcium carbonate in aqueous solutions.11. The model accounts for the forces acting on a growing bubble , pressure changes in the capillary, that portion of the liquid mass penetrating into the capillary, and the velocity of liquid flow above the nozzle. The model is very sensitive to boundary conditions; therefore, the initial minimum value of pressure in the gas supply system was set at 5 kPa. During the model simulations, the air volume flow rate was varied between 0.008 l/min, 0.014 l/min, 0.020 l/min and 0.026 l/min. From the model simulations, time series of pressure changes in the capillary and time series of liquid penetration into the capillary were calculated. Based on these time series, the maximum depth of liquid penetration into the capillary, maximum and minimum values of pressure in the gas supply system, and Δp vs. air volume flow rate were estimated. The results of these simulations are shown in Fig. In order to verify the results of the experimental investigations, results therefrom were compared to predictions from a model of bubble growth and liquid movement inside a capillaryΔp , and rn is the capillary diameter (m). For the water, the maximum value of this surface tension force is approximately 2.27 mN, and for the aqueous solution of calcium carbonate, the maximum value of this surface tension force is approximately 2.37 mN; accordingly, the air pressure in the capillary will reach a higher value when the liquid is the aqueous solution than when it will for the pure water. Furthermore, because it takes longer for the larger maximum surface tension force to be reached in a calcium carbonate solution than for the smaller maximum surface tension force in pure water, the air bubble in the former solution has more time to grow; therefore, the air bubble radius grows to a greater value , Vb is the bubble volume, ρl is the density of the liquid (kg/m3), ρg is the density of gas (kg/m3), CM = 0.5 is the added-mass coefficient for a sphere, vpp is the velocity of the liquid around the bubble relative to the bubble’s expanding shell (m/s), and xc is the position of the bubble centre (m). The bracketed term in Eq. (vpp to account for the motion of the liquid surrounding the bubble.The time at which the air bubble leaves the tip of the glass capillary corresponds to the moment at which the maximum surface tension force acting at the air–liquid interface of the bubble and described by the following equationFd), given by Eq. , given by Eq. , s is the cross-sectional area of the capillary (m2), pc is the gas pressure in the plenum chamber (Pa), and Co = 2 is the drag coefficient of moving water inside the capillary21.Models of liquid movement inside capillaries are described in the literatureOn the one hand, a greater surface tension force in aqueous solutions of calcium carbonate facilitates penetration into the capillary, and the maximum depth of liquid penetration is higher than for pure water, for which the surface tension force is lower. On the other hand, a greater surface tension force hinders the removal of the liquid from the capillary. Consequently, the air velocity entering the capillary is greater for pure water than for aqueous solutions of calcium carbonate, and the effect is to lower the air pressure in the capillary when pure water is used.τ), attractor reconstruction, correlation dimension (D), and largest Lyapanov exponent (λ). Time series data of air pressure and depth of liquid penetration into the capillary are presented in Fig. Nonlinear methods are used to evaluate the periodicity of bubble departures. These methods include: time delay . The proper value of time delay (τ) was estimated using the following criterion31:Ca) of the form given by32:N is the number of samples, and xi is the value of ith sample.Attractor reconstruction was carried out using stroboscope coordinationD, was calculated using the Grassberger-Procaccia algorithm32.The correlation dimension, 33:m—number of examined points, t—time of evolution, d(xj)—distance between points at t = 0, d(xj)—distance between points at t = te.To identify the chaotic character of the time series data, the largest Lyapunov exponent was calculated according to the following formulaτ from these tables are used to reconstruct the 3D attractors for the pressure change and liquid penetration time series.The 3D attractor reconstructions for both the pressure change and liquid penetration time series are presented in Fig. The largest bubble departure periodicity is observed for water at an air volume flow rate of 0.005 l/min. In this case, the largest Lyapunov exponent is equal to 1.86 [bit/s] for the pressure change series and 1.87 [bit/s] for the time series representing the liquid penetration into the capillary.An increase in the air volume flow rate resulted in an increased level of chaotic behaviour for the bubbles departure. In fact, the values of the largest Lyapunov exponents for an air volume flow rate of 0.026 l/min and liquid water are: λ = 13.41 [bit/s] for the pressure fluctuations data and λ = 14.99 [bit/s] for the time series representing the liquid penetration into the capillary. For c–c aqueous solutions, pressure fluctuations and depths of liquid penetration into the capillary became more chaotic—values of λ increase.In the present paper, experiments to determine the influence of small changes to water hardness on the nonlinear behaviour of liquid penetration into a capillary and air pressure fluctuations during subsequent bubble departures were conducted, and the results compared favourably to model predictions.σ = 72 mN/m) and c–c aqueous solutions (σ = 75 mN/m). The conclusions of this analysis are:A small increase in water hardness causes an increase in the surface tension force and, therefore, an increase in the pressure at which bubbles depart.The surface tension force is lower for water than for aqueous solutions of calcium carbonate; therefore, air bubbles grow faster in water than in aqueous solutions of calcium carbonate.The increase of air volume flow rate when pure water is used causes a decrease of bubble growth time because the gas momentum increases and, therefore, the bubble departure pressure becomes lower.For greater air volume flow rates in systems using water, the effect of the gas momentum, which is not dependent on the water hardness, during the bubble growth stage becomes higher than the effect of the surface tension force.A small increase in water hardness causes the velocity of liquid movement into the glass capillary to decrease.p during a single cycle of bubble departure has a greater impact on the dynamics of liquid penetration into the capillary than the changes of surface tension force.An increase in the air volume flow rate causes a decrease of liquid height inside the capillary; accordingly, it can be assumed that for greater air volume flow rates, the changes of ΔFor greater air volume flow rates, the differences between maximum depths of liquid penetration into the capillary decreases.The liquid penetration into the glass capillary with internal diameter of 1 mm was analysed in water (τ), attractor reconstructions, correlation dimension (D) and largest Lyapunov exponent (λ). For systems containing the c–c aqueous solution, pressure fluctuations and depths of liquid penetration into the capillary became more chaotic than for systems containing pure water, evidenced by increasing values of λ. Lastly, it can be concluded that:Small increases in water hardness cause the bubble departure process to become more sensitive to the occurrence of chaotic pressure changes and chaotic changes of liquid penetration into the capillary. Consequently, better control of gas bubble departures in applications can be achieved by careful control of a liquid’s physical parameters.The bubble departure periodicity was estimated using the following non-linear data analysis methods: time delay (


Although magnesium alloys are lightweight, recyclable and relatively cheap, they suffer from poor ductility. This can be improved by the addition of rare earth (RE) elements, and this is now a well-established criterion for wrought alloy design. It is notable that this behavior is largely restricted to the lanthanides, but no hypothesis is yet available to explain why other elements do not have the same effect. To answer this question, ab initio simulations of crystallographically complex boundaries have been undertaken to examine the electronic origin of the RE effect. While the electronic structure provided strong bonding between the RE elements and their Mg surroundings, local disruption in atomic arrangement at the grain boundaries was found to modify this effect. This work shows quantifiable changes in electronic structure of solutes resulting from grain boundary crystallography, and is suggested to be a contributing factor to the RE texture effect. The preferred orientation, commonly referred to as the “texture”, is a statistical measure of the alignment of the grains within a material. The ductility of magnesium alloys is more sensitive to texture variations than other metals, with a randomization of the texture being one of the key goals of alloy design. This is achieved by the addition of one of the rare earth (RE) elements, as these elements are known to be potent texture modifiers during recrystallisation. This is a general behaviour observed in the Lanthanide series of elements on the periodic table, along with Y and Ca. This is commonly referred to in the literature as the “rare earth effect”.The ductility7 and grain boundaries17, and it is the premise of the present work that the segregation of these solutes to the boundary are responsible for recrystallisation texture development14. It is our hypothesis that solutes behave differently at different types of grain boundaries. Consequently, the boundary properties such as energy and mobility will be changed when solute is present, resulting in different grain orientations being preferred during recrystallisation. Why such small concentrations of these elements, in the ppm range18 can have such a potent effect still remains unclear.It has been shown experimentally that RE elements segregate to dislocations19  restrict themselves to crystallographically simple tilt boundaries to reduce the size of the simulation to less than about one hundred atoms. However, the boundaries seen in experimentally measured materials are rarely simple or symmetrical , the < –iCOHP > at the Fermi level can justifiably be taken as a representation of the strength of bondsThe < –iCOHP > for each solute and boundary are detailed in Table If we now consider the strength of bonding for the three species, we can see that that the strength of the bond between Mg and Gd is usually higher than it is for Mg and Zn. The < –iCOHP > values shown in Table The observation of the differences between Zn and Gd begins to explain the differences in behavior we see in experimental work between different groups in the periodic table. It also somewhat explains why all of the rare-earth elements tend to have similar effects when added to magnesium alloys—they all come from column three of the periodic table and therefore share similar electronic configurations, Fig. 33. Ca is chemically similar to the lanthanides being situated next to them in column 2 of the periodic table. While its s orbital is complete, the p band of Ca is empty and the Fermi level is therefore located at the bottom of the p band (most electronic states lie at or near the Fermi level). Indeed, the RE elements and Ca share the feature that their outer shells have partially occupied bands, and all have their Fermi level located at the bottom of their outer shell band, resulting in a large density of states near the Fermi level at 0 eV. This phenomenon is reflected in their higher values of < –COHP > in the vicinity of the Fermi level indicating more stable solid solution states than Al and Zn.Table It has been argued here that the change in properties that result from RE elements located at the grain boundary is the result of the interplay between the electronic structure of the lanthanide solutes and the local atomic arrangement in the vicinity of a given grain boundary. On the one hand the outer shell of the lanthanide solute is partially occupied, and the Fermi level lies at the bottom of this shell, leading to strong chemical bonding with magnesium. On the other hand, the marked disruptions in the local atomic packing of atoms at the disordered grain boundaries, quantified by local PDF’s, have been shown to significantly modify the electronic structure of solutes located at those boundaries. This effect was found to vary significantly from one boundary to another, and the change in bonding strength (as quantified by < –iCOHP >) was mainly found to be larger for the RE elements, and lower for those elements that do not modify texture (the non-RE elements). These findings show for the first time that the RE elements are bound more strongly to grain boundaries than other solutes, and it is suggested that the preference for these elements to remain strongly bonded at the grain boundary will change other important grain boundary properties such as grain boundary energy and cohesion. The most important property for texture development is grain boundary mobility, and this too is likely to be affected by solutes strongly bonded to the boundary. Although the present study focused only on studying the behaviour of different solutes at static boundaries, mobility predictions based on the current data set are the subject of a future publication which will further interrogate this hypothesis.It is commonly argued that it is the atomic size of the RE elements that is the underlying feature that gives them unique properties in magnesium. The present quantum mechanical calculations are not inconsistent with this assertion. The large atomic radius of the RE elements make it energetically favorable for RE elements to be located at grain boundaries, while the sensitivity to the boundary crystallography and enhanced bonding can be traced back to the electronic structure, most notably, of the outer electron orbital.34 implementing the projector augmented wave method to represent the combined potential of core electrons and nuclei35. The Perdew–Burke–Ernzerhof gradient approximation was implemented to represent the exchange–correlation functional36. A cut-off energy of 400 eV was chosen for the plane wave basis and the self-consistent electronic optimization was converged to 10–6 eV. The mesh of −3. The atomic configuration is optimized using the conjugate gradient method until the mean atomic forces are less than 0.02 eV/Å−1.The simulations were carried out using the Vienna ab initio software package (VASP)24. In order to meet the required periodic boundary condition in the grain boundary plane, without rendering the ab initio simulation unfeasible due to an overly large number of atoms in the cell, the top grain was strained in the boundary plane if required. Details about the simulation cell are given in Table The simulation cells were designed to comprise two grains and a large enough vacuum layer on top to prevent interference from the out-of-plane images due to periodic boundary conditions40, the general grain boundary can be considered as a general interface between two grains (G1 and G2) represented by two slabs. As a consequence, the simulation cell total energy is the contribution of the bulk energy of grains (41:SEP and S are the work of separation defined as the reversible work needed to separate the grain boundary into two free surfaces42 and boundary area respectively.While the atomic representation of twin boundaries comprises a supercell containing two misoriented grains with a large enough vacuum layer on top43.When solute is added to the grain boundary, the segregated grain boundary energy can be expressed as


Parallel Continuum Robots (PCR) have several advantages over classical articulated robots, notably a large workspace, miniaturization capabilities and safe human-robot interactions. However, their low accuracy is still a serious drawback. Indeed, several conditions have to be met for PCR to reach a high accuracy, namely: a repeatable mechanical structure, a correct kinematic model, and a proper estimation of the model’s parameters. In this article, we propose a methodology that allows reaching a micrometer accuracy with a PCR. This approach emphasizes the importance of using a repeatable continuum mechanism, identifying the most influential parameters of an accurate kinematic model of the robot and precisely measuring them. The experimental results show that the proposed approach allows to reach an accuracy of 3.3 µm in position and 0.5 mrad in orientation over a 10 mm long circular path. These results push the current limits of PCR accuracy and make them good potential candidates for high accuracy automatic positioning tasks. They arications . The flel joints . Flexibll joints . Reducinl joints  had its l joints . This smet al. reached a positioning accuracy of 5 mm. One of the drawbacks in using black-box models is that they could not identify why the positioning accuracy was low  and a mean orientation accuracy of 3.81° after identifying extrinsic parameters of a 6-Degrees-of-Freedom (DoF) robot  after identifying all model’s parameters thanks to a calibration process  robot . The accF) robot . In the   accuracy, we considered a high-grade repeatable robot illustrated in PF robot. The actuation stages, through the prismatic joint values x, y translations and θ rotation).A global work frame In the following, we describe the model used to simulate the quasi-static behavior of the robot. First, the model of a single rod is detailed. Then, the three models of rods are linked together thanks to the static equilibrium of the platform. All those elements allow to implement the forward and the inverse kinematic models of the robot.The PCR’s model depends mainly on the modeling of the rods and its correctness, that is why a Kirchhoff-rod-based model is used. This model supposed that shear and extension can be neglected. It is possible as the used slender elements have their cross-section more than a hundred times smaller than their lengths. The proposed structure remains in a plane so, only the planar case of this model is considered without losing the generality of the proposed approach which can also be adapted for a spatial robot.l is the stress-free length of a rod. Along its arc length, The curvilinear abscissa is represented by the scalar parameter E is the Young modulus of the rod material, and I is the second area moment of the rod cross-section which depends on the rod’s diameter d.All involved differential equations can be gathered into the following system:To model the quasi-static behavior of the PCR, a forward and inverse kinematic models are created. Both result from a numerical resolution of the previous equations considering the rod’s boundary conditions and the static equilibrium of the platform.Those boundary conditions describe how the rods link the actuators to the mobile platform. They yield:i and p in the work frame.To know the pose of the platform, the static equilibrium conditions are considered:Due to the coupling between the rods, there is no analytical solution of those equations considering the previous boundary and equilibrium conditions, thus, a numeral resolution is performed using a shooting method. This shooting method is based on a optimization problem where E of its material, its diameter d and its length l), the ones representing the poses of the rods’ proximal and distal ends  are changed in the same time, the consequences on the model will be more important than if only one length was changed.The second group is composed of the angular parameters The last group is composed of the parameters that are the most influential: the length of the rods This sensitivity analysis give information about the influence of the different parameters but also indicate the threshold of uncertainty where their influence can not be neglected anymore. To give an example of comparison between the parameters’ influence, considering the values of the table, an uncertainty of 1 mrad observed on a proximal end’s orientation In order to get an accurate robot, the parameters whose influences are the most important on the model need to be estimated as precisely as possible. The next section will present the PCR design which takes into account the presented results by introducing fiducial markers. The objective of those markers is to reduce the measurement uncertainty of the most influential parameters.To validate the modeling of the robot, a prototype has been built by taking into account the previous sensitivity analysis. To perform this comparison between the prototype’s experimental behavior and its model, the PCR poses and its models’ parameters have been measured by two complementary vision measurement systems. This section introduces the robot design and the associated measurement system.The robot is composed of a mobile platform coupled to three actuated continuum limbs.Each limb is assembled on a stack of three manual precision stages, two translation stages (Newport SDS-40) and a rotation stage (Newport M-RS40). These manual stages are used to adjust the position and the orientation of each actuator fixed above them.The actuators are SmarAct (SLC-1730-S-HV) positioning stages. Their repeatability is below 30 nm and their range is 21 mm. Those actuators possess accurate optical sensors and a repeatable behavior that are necessary to get accurate inputs for the forward kinematic modeling of the PCR.E is about 69 GPa. They are able to do large deformations without viscous effect thanks to their elasticity. They are 125 µm in diameter and about 30 mm in length. Those rods are connected to the actuators and to the platform by the mean of rod mounts.The rods are optical fibers stripped of their plastic part. Those fibers are in fused silica whose Young Modulus The rod mounts are the key elements to define precisely the position of the rods’ ends and thus their length. Each rod mount is drilled on one side to clamp the rods. On the top face of the mount, a fiducial marker (QR-Code-like pattern) is engraved. Thanks to its manufacturing, the transformation between the center of the fiducial marker and the hole where the rod are inserted is known with a small uncertainty. Thus, knowing the pose of the fiducial marker will enable to know the relative pose of the proximal and the distal ends of the three rods (more details will be given in the next section). The proximal rod mounts are fixed on the actuators and the distal rod mounts are glued on the mobile platform.The platform is a 100 mm silicon wafer lifted by a 50 mm diameter air bearing (S205001) from the IBS company. This air bearing avoids friction and is preloaded to maintain a stable elevation of the platform  mounted with a 50 mm lens. This vision setup is used to get accurate measurements of the different models’ parameters of the robot. More details will be given in the next section.x, y position and the θ angle of the platform with a sub-nanometer resolution . The resolution of the measurement is less than 0.25 µm for X and Y translations and 0.5 mrad for rotation.A and the distal end B of each rod can be deduced from these markers poses. By construction, the transformations between the center of the fiducial marker and the clamping point of the rod are defined by two translations of 14 mm and 250 µm in the X and Y directions. The machining accuracy is about 6% of this transformation leading to uncertainties of respectively 840 and 15 µm. By acquiring an image close to the rod mount and the clamping area and considering the resulting pixel/meter ratio, the uncertainty in the X direction is reduced to 160 µm. Due to the value of the uncertainties and the influence of those parameters, they will need a special cares during the PCR calibration process.As the transformation between the center of the fiducial marker and the clamping hole is known, the Cartesian position of the proximal end i, is measured using 1 mm displacement of the stage with a step size of 125 µm. Each pose of the pattern is recorded during this displacement. The angle of the regression line through these points gives a precise measurement of γi. Then, the difference between this angle γi and the pattern pose provides the misalignment angle αi. The uncertainty for both angles is estimated to 5 mrad. Considering their small uncertainties, the parameters The last parameters that need to be measured are assembling defaults between the actuators and the rod mounts . The angThanks to this measurement process, nominal values of the different parameters and their uncertainties are known. This knowledge is useful to prepare the calibration of the PCR.Even with an accurate measurement process, the addition of small uncertainties reduces the PCR’s accuracy. To reduce those errors and obtain a better fitting between the experimental behavior and the model a calibration process has been implemented. In this article, three identification steps are used in this calibration process described in There are two kinds of parameters considered for the identification step of the calibration process: the intrinsic parameters The experimental poses are acquired thanks to the second vision setup as shown in n joint coordinates j-The parameters identification is based on a minimization of an objective function using a least squares algorithm. This algorithm is defined by the sum of the squares of the differences between the experimental Cartesian poses of the robot and the simulated ones using the forward kinematic model. Both experimental and simulation poses depend on a set of Using this function, the identification problem can be formalized as:The minimization of this optimization problem is performed using the built-in-function lsqnonlin from Matlab software.To increase the PCR’s accuracy, the parameters can be identified after their measurements. This initial measurement of the parameters enables the reduction of the parameters’ uncertainty intervals. Small intervals help to avoid some local optima and ensure consistent parameters during the minimization. Moreover, the sensitivity analysis helps to distinguish the most influential parameters that should be identified in priority. Indeed, the parameters could not be identified at the same time if their values are too far from their true values. For this reason, the identification is carried out in three steps using the same experimental data.The parameters that need to be identified first are the extrinsic parameters As previously explained, the joint coordinates have been chosen inside the robot’s workspace in which it has a nanometer repeatability. These joint coordinates are sent to the robot and the Cartesian coordinates of the platform are recorded. To ensure a good distribution in the available workspace, the joint coordinates have been randomly chosen using a 3-dimensional Poisson-disc sampling. A set of 99 joints coordinates, more than three times the number of considered parameters, is created to perform their identification. 56 joints coordinates are selected to validate the identified parameters. j is defined as the root mean square of the difference between the simulated position The position error of the pose Similarly, the orientation error is:To check the validity of the identified forward kinematic model, simulations are performed with a validation set of joints coordinates. For both sets, the maximal resulting position modeling error is 15.26 µm corresponding to 0.05% of the 30 mm length of the flexible rods.This section presents the results of the proposed methodology on the PCR’s accuracy. To quantify this accuracy, the robot is controlled in the Cartesian space. This control depends on the inverse kinematic model whose parameters resulted from the calibration process.The forward kinematic model enables the prediction of the pose of the robot considering the joint coordinates as inputs. Conversely, the inverse kinematic model allows to calculate the joint coordinates corresponding to a given pose in the Cartesian space. A regular scheme for controlling the position of the robot in the Cartesian space using the inverse kinematic model is implemented as illustrated in To validate the capability of the robot to reach commanded poses in the Cartesian space, two trajectories have been considered: a 2 mm side square and a 3 mm diameter circle with a constant null orientation of the mobile platform. Those trajectories are used as an input for the inverse kinematic model which returns the corresponding joints coordinates The robot accuracy evaluates the closeness of agreement between the pose attained by the robot and its commanded pose. The accuracy of a robot is defined by the standard ISO 9283:1998. The positioning accuracy is the difference between the commanded position and the barycenter of the reached positions:The accuracy of the robot has been evaluated for the two trajectories as shown in For both trajectories (square and circle), the pose accuracies depend on the pose of the platform. For instance, in the square trajectory, the orientation accuracy is worst in the corners. A deeper analysis on the experimental data of the calibration process shows that the angular errors are linked, with a correlation ratio of nearly one, to the differences between the initial angle and the current angle. Larger the orientation of the platform, higher is the angular error. Correlations between the position and the angular error are less straightforward to establish with typical ratios between 0.52 and 0.74. With local studies on different areas of the workspace, there are some locations near the workspace borders were the position errors are increased. In conclusion, the model is more accurate in the middle of its workspace in both orientation and position.In this article, a methodology to reach micrometer positioning accuracy is proposed.XYΘ planar Parallel Continuum Robot (PCR), the maximal reached positioning accuracy is 3.3 µm in position and 0.5 mrad in orientation over a 10 mm-long circular trajectory.This micrometer positioning accuracy was reached thanks to the proposed methodology which consists in five key elements. The first one is the use of a repeatable PCR structure to be able to predict the robot’s quasi-static behavior. The second element is to use a correct mechanical model. The third one is the use of fiducial markers in the design of the robot. Those markers allow to efficiently measure the nominal values of the model’s parameters and to estimate their uncertainties. The fourth element is to conduct a sensitivity analysis to quantify the influence of the different parameters and find the most influential ones. This crucial information is considered in the robot design to be able to efficiently measure those parameters thanks to fiducial markers. The last step is to calibrate the whole robot by identifying all the parameters through three optimization steps. Using this approach on a In addition to the already recognized advantages of PCR , the obtained results make also PCR worth to consider for high precision positioning tasks.


The COVID-19 pandemic has led to the rapid adoption and rollout of thermal camera-based Infrared Thermography (IRT) systems for fever detection. These systems use facial infrared emissions to detect individuals exhibiting an elevated core-body temperature, which is present in many symptomatic presentations of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Despite the rollout of these systems, there is little independent research supporting their efficacy. The primary objective of this study was to assess the precision and accuracy of IRT screening solutions in a real-world scenario. The method used was a single-centre, observational study investigating the agreement of three IRT systems compared to digital oral thermometer measurements of body temperature. Over 5 days, 107 measurements were taken from individuals wearing facial masks. During each entry, two measurements of the subject’s body temperature were made from each system to allow for the evaluation of the measurement precision, followed by an oral thermometer measurement. Each participant also answered a short demographic survey. This study found that the precision of the IRT systems was wider than 0.3 °C claimed accuracy of two of the systems. This study also found that the IRT measurements were only weakly correlated to those of the oral temperature. Additionally, it was found that demographic characteristics  impacted the measurement error. This study indicates that using IRT systems in front-line scenarios poses a potential risk, where a lack of measurement accuracy could possibly allow febrile individuals to pass through undetected. Further research is required into methods which could increase accuracy and improve the techniques viability. In an in-patient setting, core body temperature can be assessed from different body locations using oral, rectal, tympanic or temporal artery thermometers, or even through urinary or pulmonary artery catheters with in-built temperature sensors2. The accuracy, precision, advantages and disadvantages of these temperature measurement devices in clinical settings has been well established4.Core body temperature is one of the four key vital signs, which is regularly assessed by healthcare settings, alongside respiration rate, blood pressure and heart rate5. The use of evidence-based assessment to evaluate technologies for use in a hospital setting is a common and critical part of modern healthcare, ensuring patient safety and assisting in the delivery of high-quality care6.In addition, in modern medical practice, every device must be assessed against national and international regulations. To ensure that a device meets appropriate levels of quality, accuracy and safety, strict medical equipment certification standards must be met by the device prior to its use in a clinical setting. The bodies administering these standards for medical devices include the Therapeutic Goods Authority in Australia, the Food and Drug Administration in the USA and the Medicines and Healthcare products Regulatory Agency in the UK7. As fever is present in a significant proportion of symptomatic SARS-CoV-2 cases, the goal of the screening is to identify individuals exhibiting an elevated temperature, isolate them, and refer them for a more comprehensive assessment to a health practitioner8. Currently, fever screening technologies are typically installed in high-traffic areas, such as train-stations or airports, and also at the entrance of high-risk sites, such as hospitals, where the consequences of an outbreak could be catastrophic. Many of the deployed fever screening solutions have not yet been assessed by regulatory agencies.The COVID-19 pandemic has led to an unprecedented adoption and rollout of new fever detection technologies9. When compared to this ideal screening technology, it is clear that traditional measurement techniques have a variety of limitations which restrict them from being highly suited for use as mass-screening tools. Traditional hospital-grade, contact-based measurement techniques all require close proximity between the test administrator and the subject, and some methods are too invasive, too slow, or too expensive to be widely used. This has led to the increased adoption of infrared thermal detection systems for fever screening applications.The ideal screening technology must be accurate, rapid, widely available, and operate in a way that keeps both the test administrator and subject safe from viral transmission. In addition, an ideal solution would operate without consumables to deal with global supply chain shortages of critical resources, such as consumables, personal protective equipment (PPE) and medical devices, which have been experienced during the COVID-19 pandemic10. The thermal radiation is converted through a transducer to an electrical signal which can be interrogated and measured on-board of the device. In fever screening applications, detection systems fall into two main categories: handheld Non-Contact Infrared Thermometry (NCIT) devices, and Infrared Thermography (IRT) systems. These systems meet many of the criteria for a successful mass screening system, they are non-contact, require no consumables, are rapid, and in the case of IRT systems the operator can be physically distanced from the subject. While the use of NCIT devices has been explored in a hospital setting through a number of clinical trials and research articles, and that many of NCIT devices have achieved appropriate medical device approvals, these are not yet established for most IRT systems13.Infrared thermal detection systems operate through the measurement of thermal radiation emitted in the infra-red wavelengths, of the electromagnetic spectrum14, and a similar result found from a study conducted in the USA in 2010, reporting a sensitivity of 91.0% and specificity of 86.0%. However, these results were not found to be broadly repeatable, as revealed by three experiments performed in Hong-Kong and New Zealand between 2011 and 201317. The most recent of these studies only reported a maximum sensitivity and specificity of 64% and 86%, respectively, when measurements were taken in a comparative manner15. International standards such as the ISO/TR 13154:201718 which are used to explain and outline current best-practice approaches suggest a number of considerations to be taken into account  when performing fever screening. The existing studies did not report that any of the systems which were installed according to these standards. This is likely due to the fact that the finalised version of the ISO/TR 13154:2017 standard was released after the studies were conducted.Despite the wide-spread use of IRT systems, there remains limited independent evidence demonstrating their efficacy and accuracy when measuring body temperature for fever screening. Some clinical trials have been conducted, but the results have been mixed, and there is a lack of consensus in the literature on the effectiveness of IRT systems. A 2015 study in Singapore found that one system was able to achieve a high level of sensitivity and specificity As such, this study, conducted in Australia during the COVID-19 pandemic, evaluates the precision and accuracy of three different types of IRT system for human temperature measurements when installed in a real-world scenario with a mask-wearing population. This was performed to determine their efficacy as screening systems, when compared with a certified benchmark temperature measurement device commonly used in hospitals.The investigation was designed as a single-centre observational study comparing the accuracy of three IRT systems to core-temperature measurements taken using certified oral thermometers. Additionally, the precision of each IRT system was determined through repeat measurements.The study was conducted at a University during a 5-day period in August 2020 from 9 a.m. to 5 p.m.The study was performed on a community sample and used a convenience method for participant recruitment. The study aims, participation requirements, and methods of consent and requirements of participation were provided in an email to staff and students in the building. Verbal consent was gathered on the day. These measures were performed to ensure that social distancing guidelines were able to be maintained during the study. Every employee and student who attended the building during the study period was invited to participate. Due to the nature of the facility, the participants were all over 18 years of age.This study was approved by the Deakin Human Ethics Advisory Group   at Deakin University . All methods were performed in accordance with the recommendations of the Ethics Advisory Group as well as the relevant guidelines and regulations. Informed consent was gathered from every participant, prior to their inclusion in the study and all data was anonymised before being stored in a secure double identifier password protected REDCap (Research Electronic Data Capture) database administered by Deakin University with access limited to the study investigators.System 1—A dual-camera system with a 40 °C external reference temperature device (blackbody), advertised to be able to measure up to 30 subjects simultaneously while performing facial recognition tasks.System 2—A single camera system with laser-assisted autofocus which operates without a blackbody.18.System 3—A single camera system with a 35 °C blackbody which is deployed in-line with the guidance provided in the ISO/TR 13154:2017 technical standard (apart from the guidance on masks)Three IRT systems were selected for use which represented three of the main types of systems that are being sold in the Australian market. These were as follows:The specifications for each system are included in Table Each of the three IRT systems were loaned to the researchers by the manufacturing companies for the purpose of conducting this experiment. To ensure the independence of this trial, each company provided the equipment free of charge and signed a research services waiver giving the researchers the right to publish the results without commercial input or oversight. The IRT systems were all setup according to the manufacturer’s directions. The researchers were provided training on the assembly, deployment and operation of the IRT systems to ensure correct operation. Each manufacturer confirmed the configurations of the systems, the setup environment and the experimental methodology prior to the beginning of the trial through video conference but were otherwise uninvolved in the experiment.The setup conditions of the three IRT systems are visualised in Fig. The area was not directly under any active Heating, Ventilating, and Air Conditioning (HVAC) system.The room in which the trial was located was temperature and humidity controlled.No lights or thermal radiation sources were directly in view of any of the cameras, and the cameras were not pointed at any reflective surfaces.Each IRT system was allowed 30 min of temperature stabilization each day prior to the first measurement being taken.The room had no direct entry from the outside, each doorway had an airgap which had to be traversed prior to entering the experimental area.Systems 2 and 3 were focussed at the beginning of the trial, and focus was checked four times per day . The manufacturer of System 1 indicated that manual focussing was not required.Systems 2 and 3 were directly in-line with the subject’s face. The manufacturer of System 1 indicated that this was not necessary.TV Screens were setup for Systems 2 and 3 so that subjects could orient themselves within the camera targeting area. System 1 used a web-based application and a laptop to display the data.The conditions of the experimental environment were as follows:Every step of this experiment was strictly conducted according to socially distancing guidelines between the researcher and the subject.“Have you experienced any fever symptoms in the last 24 h?”“If yes, did you take any medications to treat your fever in the last 4 h?”“Have you experienced any symptoms in the last 24 h of sore throat, cough, runny nose, loss of taste or smell?”Have you had a hot or cold drink in the last 30 min?As a potential participant entered the building, they were approached by the researcher who confirmed their knowledge of the study (information which had been provided through email) and asked for their verbal consent. If the answer was in the affirmative, the participant then verbally completed a questionnaire of demographic data , and also was queried as to their current health status, in particular:This data was entered into a case report form for each individual in a secure REDCap (Research Electronic Data Capture) database.The participant was then questioned to if they had been outside the building in the past 5 min, if the answer was in the affirmative, they were asked to wait for 5 min to acclimatise. The purpose of this was to avoid readings from being impacted by the exterior environment. The participants were also asked to remove hats or glasses to ensure accurate readings.19.All participants were wearing masks during the trial, apart from when using the oral thermometers, as during the SARS-CoV-2 pandemic in Victoria, Australia, there was a state-wide mandate that all individuals must wear masks when outside their own homes, this means that any screening technology used during this time would be required to operate with masked participantsEach participant was then asked to spend 5 s standing in front of each IRT system facing directly into each camera at a distance of 1.5 m (indicated by a mark on the floor). This was then repeated, to give two readings for each time an individual participated in the experiment. At the conclusion of these measurements , the participant was provided with a DT-01B oral thermometer (Measurement accuracy: ± 0.1 °C [35.5–42.0 °C]) and requested to stand in an isolated location (indicated by a mark on the floor), where they proceeded to take an oral thermometer reading. The two readings from each IRT system and the single oral thermometer reading were then entered into the secure REDCap database case report form.The RStudio integrated development environment for R  was used for the statistical analysis, and for all tests, a 0.05 level of significance was used. The frequency distribution (reported as mean and standard deviation), was calculated for the participant’s age, the number and percentage distribution of the participant’s gender, and mask-type were also calculated.An investigation into the measurement precision was then performed to analyse the difference between the first and second measurements of each IRT system and to determine if the claimed 0.3 °C of accuracy was observed in a multi-measurement precision test. This precision error was also reported as a boxplot to observe the distribution of the quartiles as well as to identify outliers. The frequency distribution of the precision error was then calculated and reported as mean and standard deviation.20).The measurements of the IRT systems were then compared against the reading of the oral thermometer, and the mean and standard deviation were calculated. The Pearson's correlation coefficient (ρ) was also calculated to determine the correlation between the measurements. The thermal camera measurements, in comparison to the oral thermometer readings were then fitted to a linear model, and the coefficient of determination for each system was calculated. The error of each measurement for the three systems was then calculated. Finally, the accuracy was assessed in relation to each of the demographic attributes , the mean and standard deviation of the error was calculated, and tests of statistical significance between the systems were calculated using Welch’s t-test  which is due to a level of selection-bias, as these symptoms would have precluded their entrance to the campus.The first test performed on the IRT systems was to determine if the systems were able to achieve a precision of within ± 0.3 °C through a repeated measurement precision test, the results are shown in Fig. 4. Firstly, there were significant differences found between the IRT systems and the oral thermometer measurements with the mean difference in System 1 being 0.26 °C, System 2 being − 1.90 °C, and System 3 being − 1.31 °C. In addition, the correlation coefficients calculated were weak (< 0.5), with System 3 being the most correlated to the oral thermometer results (ρ = 0.49) and System 1 being the least (ρ = 0.33).The second test compared the IRT system readings against the oral thermometer to determine how correlated the readings from each system were to core body temperature. While not required to be exact, an accurate system for detection of elevated body temperature should have a strong degree of correlation with the oral thermometry readings, with an increase in core temperature resulting in an increased IRT measurement. The results of this test were tabulated and are displayed in Table 2), with the strongest being System 3 (r2 = 0.24) and the weakest being System 1 (r2 = 0.11).A linear model was developed for each of the systems relative to the oral thermometer results and is displayed as a bubble-plot in Fig. 20). These results were tabulated and are displayed in Table In addition to examining the participants in aggregate, a set of analyses was also performed to determine if any of the recorded demographic attributes had an impact on the measurement error experienced by the IRT systems compared to the oral thermometer. For each of the recorded characteristics , the mean and standard deviation of the error and p-values were calculated, using Welch’s t-test  and was found to report the correct temperature within 0.1 °C, demonstrating its high degree of measurement accuracy.IRT systems are being installed in a wide variety of locations worldwide in response to the COVID-19 pandemic. Yet, there is limited evidence available in the literature reporting on their accuracy or efficacy in these application spaces, in particular on how they correlate to core-body temperature measurements. In order to address this research gap, the current study investigated the use of three different IRT systems from different manufacturers in a real-world setting, with a community mask-wearing population.2 with values of 0.49 and 0.24, respectively. Fourthly, the participant characteristics were associated with changes in the error between oral measurements and IRT systems measurements, however, these were not consistent across all three IRT systems.Firstly, the precision of each of the three systems was determined through repeated measurements taken a short time apart (< 30 s). Each of the systems were found to have a precision wider than the 0.3 °C accuracy claimed by two of the systems. Secondly, in regard to measurement accuracy, our results suggest that the IRT systems each experience a deviation from the core temperature measurements. Thirdly, this study has shown that in our sample, the IRT systems measurements only have a weak correlation to the oral temperature measurements, with System 3 having the highest ρ and r21. These studies were also conducted with participants > 18 years of age and with multiple IRT systems. However, neither of these studies were conducted with a mask-wearing population, and nor with IRT systems installed at the first stage of entry to a building as in our study, which is a common use-case for these systems in hospitals and workplaces in 2020. In addition, the study by Nguyen et al.21 which found the IRT systems to be sensitive and specific, was performed on individuals after they had been registered in the emergency department, which may have allowed for an extended period of acclimatisation time when compared to a regular building entry.Some existing studies have found IRT systems to be sensitive and specific in assessing the febrile status of subjectsOur study is the only recent study reporting on repeated measurement precision of the IRT systems, this is a significant result as it describes the repeatability of the system when measuring the same person multiple times. From our results it seems unlikely that a 0.3 °C level of accuracy would be achievable with such a wide measurement precision in each of the systems. Indeed, all 3 of the systems reported measurements with differences of > 0.5 °C on the same individuals only 30 s apart.22, and the ISO/TR 13154:2017 standard suggest that using an external reference device (blackbody) increases the accuracy of the measurements. Our study results show that this is a good recommendation; System 3, which used a blackbody reference, had a mean difference 0.59 °C closer to the core temperature measurement than System 2, which used a similar camera without a blackbody. In addition, System 3 was found to have a greater correlation to core temperature than System 2, with their respective correlation coefficients being 0.491 and 0.407.The research conducted by Ghassemi et al.22. Our study found that System 1 which was not specifically taking measurements from the inner canthus in fact reported measurements which were closest to the core body temperature measurements (mean difference increase of 0.26 °C). This was an unexpected result, as the literature suggests that the facial skin temperature is generally expected to be lower than the core-body temperature23. This suggests that System 1 is employing a correction algorithm on the measurement results, which may shift the measurements into a more “acceptable” range. Additionally, the measurements from System 1, which were not taking measurements from the inner canthus were found to have the smallest coefficient of determination of any of the systems to the core body temperature (r2 = 0.11). This suggests that the use of the algorithm does not significantly improve the efficacy of whole-face temperature measurement, and that the current guidance is correct in recommending measurements be taken from the inner-canthus region over a general facial measurement.The current ISO standards also recommend that measurements should be taken from the inner canthus of the eye rather than the forehead or general facial measurements24. However, the study by Chan et al.15 found that the correlation is higher among febrile populations with core-temperatures ≥ 38 °C, which we were not able to include in our study, so the correlation may have been improved with a population including a large cohort of febrile individuals.The correlation found in our study (maximum being ρ = 0.49) is generally in agreement with the existing literature, which reported values between 0.3 and 0.5 for well-functioning systemsThe experiment involving the validation of System 2 against external temperature reference devices (blackbodies) demonstrated that this system is capable of measuring emitted thermal radiation with a high degree of accuracy in the experimental environment. When measuring these near-ideal sources, System 2 reported a measurement value within 0.1 °C of the expected temperature, which is within the margin of error of the reference device. This suggests that the measurement error observed in experiments with human subjects is likely due to the physiological link between core-temperature and facial temperature, rather than inherent technological error.4, thus a study into the temperature differences of demographics would be of limited use. Thus, this work investigated how these demographic factors impact the accuracy of the measurements taken when using IRT measurement systems. Our study found that demographic characteristics had a significant impact on the measurement error of the systems, however, this was not consistent across the three IRT systems. System 1 which measured the whole face temperature exhibited an increased error on subjects ≥ 40 years of age, and those who were wearing thinner masks. Systems 2 and 3 which measured the inner canthus of the eye had an increase in error on subjects who identified as female. This is in agreement with existing literature which suggests that gender and age are factors which impact measurement accuracy of infrared thermography systems21.Existing research into normal body temperatures has found that the normothermic difference between different demographics  is smaller than the error range of our measurement devices (0.3 °C)12. Finally, we do not believe that the use of masks had a significant impact on the effectiveness and efficacy of the measurements being taken. As the systems were not targeting regions of the face covered by the mask it is unlikely that the inclusion of a mask altered these temperatures, particularly the systems that were measuring the inner canthus region. From observing the systems during operation it was clear that each system was able to quickly and correctly identify the facial location to be measured, indicating that the masks did not make an impact on the facial positioning algorithms being used. This could be confirmed through a specific research study.To the authors’ knowledge, this is the first IRT study which has reported face-mask type as a demographic factor and investigated its impact on measurement error. Our earlier study using NCIT devices in a hospital setting found that demographic factors  also impacted measurement results, so it appears that there is scope for future research to determine their precise impact on the performance of infrared measurement systems in fever-screening scenariosTo the authors’ knowledge, this the first study of this type which has been conducted on a mask-wearing population, which was a mandated intervention in Victoria, Australia during parts of the COVID-19 pandemic. The limitations of the study were as follows: this was a convenience selected community sample, with no febrile subjects, there were no subjects > 65, the duration of the camera loan agreements and facility agreements dictated a one week timeframe which restricted the sample size. Additionally, the variations in height of individuals impacted the measurement process as some subjects had to bend, lean, or use chairs in order to be in focus in the measurement. Also, this study had a larger population of male (71.96%) than female (28.04%) participants, this may impact the translation of the results. The inclusion of an NCIT device could have allowed for the exploration of the source of the measurement error, and finally the lack of febrile individuals made it impossible to assess the sensitivity and specificity for individual febrile detection.There is a clear need to expand this study into a setting with more febrile individuals to allow for the assessment of sensitivity and specificity of fever detection, however, the low correlation values found between each of the measurement sources raises doubt to the efficacy of these systems at detecting individuals with low-grade fevers (37.5–38 °C). Also, there is clearly scope for future research into investigating the impact of camera characteristics on measurement results. This would involve creating a study where multiple cameras with varying characteristics from multiple manufacturers would be tested in the same setup conditions to determine the impact of the technical characteristics on the measurement results. Another avenue of investigation for future research would be a quantitative determination of the impact of masks on IRT system measurements. A study in which each participant is measured both masked and un-masked and the associated results compared, would be a great addition to the literature and allow for a quantitative determination of the impact of masks on IRT measurements. In addition, there is clear scope to perform further investigations into the impact of age and gender on the measurement results. Finally, there is clearly an interesting avenue of investigation in relation to improving the precision of these measurement techniques for mass screening .This paper presented the first study on assessing the capabilities of IRT systems in a face-masked population in a real-world mass screening scenario. This system was tested outside of a hospital setting, at the entrance to a research facility within a building, mimicking the installation scenario of many currently operating IRT systems. Our results show that using the systems as a front-line intervention for fever-screening poses a potential risk, where the lack of measurement repeatability could negatively impact sensitivity and specificity, possibly allowing febrile individuals to pass through undetected. Although these systems are currently seeing widespread use due to the COVID-19 pandemic, our results show that there is still further research required to improve their precision and accuracy so that users can be confident in their operation. There remains an opportunity for new technology to meet this gap.Supplementary Information.


Scanning electrochemical microscopy (SECM) is able to track the local electrochemical activity of an electrolyte‐immersed substrate employing an ultra‐micro‐electrode (UME) in micrometer‐scale spatial resolution. In this study, SECM is employed to investigate the presence of oxygen in the electrocatalyst layers of polymer electrolyte membrane fuel cells and electrolyzers. Approach curves on electrocatalyst layers with the tip potential set for oxygen reduction reveal that a significant amount of oxygen is absorbed in the catalyst layer. We confirm that the coexistence of Nafion ionomer and carbon black leads to oxygen confinement. It is suggested that this oxygen is confined within the hydrophobic parts of the self‐assembled Nafion on the graphitic surfaces of the carbon black. Absorption of oxygen into the electrocatalyst layer only in the presence of Nafion  is confirmed using scanning electrochemical microscopy. This is justified from a positive feedback when the tip approaches the layer containing both catalyst and Nafion. In contrast, a negative feedback is observed for both the catalyst and Nafion, when tested separately, indicating no significant amount of oxygen is absorbed into either of them. Micrometer scale spatial and millisecond scale temporal resolution is obtained with typical microelectrodes. SECM has been utilized in various applications from biology[Thus far, SECM has been widely used to investigate the electrocatalytic activities of various catalysts for both hydrogen oxidation (HOR) and oxygen reduction (ORR) reactions in different modes, including “Tip Generation Substrate Collection“ (TG‐SC), “Substrate Generation Tip Collection“ (SG‐TC), and Feedback modes.[et. al attributed this performance enhancement to the extension of three dimensional reaction zone, which is the contact of catalyst, reactants and the electrolyte, by Nafion.Incorporation of Nafion ionomer in PEMFCs electrodes was firstly reported by Raistrick more than 30 years ago. Their cell with Nafion impregnated electrodes was as efficient as a cell containing a 10 times higher loading of Pt in the catalyst with no Nafion on the electrodes.Nafion ionomer exhibits a self‐assembly behavior in aqueous solutions.[In the SECM feedback mode, the biased UME tip vertically approaches the substrate and the redox mediator of interest present in the solution (oxygen in this work) is reduced at the tip. When the tip travels within the “bulk solution“  the oxygen. To equilibrate the chemical potentials of oxygen in the solution and across the interface, oxygen partitioning takes place and additional oxygen is supplied from across the interface, or from within the porous interface. For example, an oxygen partition induced positive feedback is observed when approaching a liquid‐air interface,et al.To investigate the effect of Nafion, different approaches were taken. In two substrates, the catalyst (20 wt‐% Pt on carbon black) was in contact with Nafion. Firstly, the catalyst ink was spray‐coated on the Nafion 115 membrane, as described by Sorsa The substrates were experimented on using the SECM setup shown in Figure 2IT, vs. the normalized tip distance from the substrate, L. IT is defined as iT/iT∞ where iT is the measured reduction current at the tip and iT∞ is the steady‐state current measured in the bulk solution. L is defined as “d/a“, where d is the tip‐to‐substrate distance and a is the tip electroactive radius, defined in Figure Approach curves in Figures L values are observed in catalyst coated Nafion membrane. Two factors might give rise to this deviation. Firstly, the membrane is not fixed as in the other experiments with glassy carbon as the substrate; therefore, it may not be completely horizontal. Secondly, on a microscopic scale the membrane might include some waves in the surface that affect the solution interaction volume while the tip is a few microns away from the membrane.As shown in Figure L) in figures Approach curves for the Nafion ionomer and Nafion‐free catalyst ink drop‐casted on a glassy carbon electrode, and for the Nafion membrane are shown in Figure As the tip is biased for the oxygen reduction potential, any current increase while the tip is approaching the substrate is attributed to the oxygen in excess of the solvated oxygen in the electrolyte. In this way, positive feedback indicates that there is an excess of oxygen absorbed in the catalyst layers. In contrast, when the tip current decreases as the tip approaches the substrate, the solvated oxygen would be the only source for the tip current, and the substrate would act as a block for oxygen diffusion to the tip. Therefore, negative feedback indicates that no significant amount of oxygen is present in the substrate.Based on the observed negative feedback response, it is therefore clear that pure Nafion does not significantly absorb oxygen. Moreover, the drop‐casted catalyst on glassy carbon without the presence of Nafion appears to be unable to confine large amounts of oxygen within its structure as in its mixed response the tip current still decreases to lower values than the limiting current while approaching the substrate Figure .On the other hand, the Nafion impregnated catalyst shows a positive feedback response in both acidic and basic environments. The catalyst layer coated Nafion membrane exhibits a positive feedback response as well. In other words, it appears that both Nafion and high‐surface area electrode are required for the presence of excess of oxygen.An elementary assumption is that the oxygen trapped within the substrate during the coating, or the drop‐casting processes would be the source of excess of oxygen and a consequently positive feedback response. The trapped oxygen is a temporary  source for oxygen in the substrate and after it is depleted from the substrate, the positive feedback should not be observed anymore. To investigate this, the glassy carbon substrate was biased for the ORR potential (−0.6 V in KOH 0.1 M – refer to SI) so that any present oxygen within the substrate is reduced and the substrate is depleted from oxygen. During the ORR on the substrate the tip was located a few microns away from the substrates being biased for the same potential as the substrate (−0.6 V). The tip current for oxygen reduction reached zero, confirming that all the oxygen within the substrate along with the solvated oxygen in the solution in the vicinity of the substrate (the zone where the tip was located) was consumed during the ORR on the substrate. Next, the substrate was unbiased again and the current flow at the tip (biased for −0.6 V) was measured. The tip current increased gradually and after 30 minutes reached higher values than the limiting current (bulk current), similar to the observed increased currents in the approach curves. As the current increased to higher values than the bulk current (current due to the reduction of solvated oxygen far away from the substrate), some oxygen is again supplied from the substrate while the oxygen had been depleted previously from the substrate. It shows that the amount of oxygen in the substrate was recovered by diffusion and partitioning from the bulk electrolyte into the substrate in an equilibrium. Therefore, the oxygen entrapment assumption is not valid and instead oxygen is thermodynamically stable within the substrate.As discussed earlier, it is suggested that oxygen can be confined (absorbed) in the hydrophobic part of the self‐assembled Nafion ionomer on the graphitic surfaces of the catalyst's support (carbon black).[To investigate whether or not platinum particles are also required for oxygen confinement, carbon black without any catalyst particles was mixed with the Nafion solution in two different ratios and utilized as SECM substrate. As shown in Figure 2.1ca. 100 times more oxygen in the extra phase) and transfer rate (>100 s−1 from extra phase to electrolyte) when the diffusion coefficient of the oxygen in the water is used for oxygen in the extra phase. If the oxygen diffusion in the air is considered instead, a positive feedback response is also obtained with low partition coefficients (down to 1) if the transfer rate is very high (>1000 s−1).To better understand the observed behavior, finite element simulations of the system were performed, as described in the SI. The excess oxygen in the electrode was described as an extra phase, with a partitioning coefficient of oxygen governing the equilibrium between the two phases. The other important parameters are the transfer rates of oxygen between these phases, as well as the oxygen diffusivity in this phase. This phase can be thought either as a gas phase, or as another phase of oxygen absorbed on the carbon surfaces. The simulations show that a positive feedback response is achieved with a sufficiently high partition coefficient ,Another interesting question is that if the absorption effect is only limited to the oxygen. We believe that other gasses such as hydrogen will show the same behavior, but this should be tested experimentally. In addition, how does the hydrophobicity of the catalyst layer contribute to the absorbed oxygen? And does this change under operation? We have shown that SECM is a good tool to measure these effects, but better quantification of the experimental results is required. This requires better knowledge of the structure of the electrocatalyst layer, including porosity. Additionally, operando spectroscopy measurements of the liquid and gas phase fractions would be beneficial, as at the moment these parameters remain open questions.3The SECM feedback mode is used to evaluate the Nafion induced oxygen confinement or absorption in electrocatalyst layers. The positive feedback response of the SECM test indicates that large amounts of excess oxygen is present in the substrate, while the negative feedback indicates the absence of additional oxygen. Due to the negative feedback response, Nafion in either form, the drop‐casted solution on glassy carbon, or the membrane, cannot confine the oxygen in its structure. Moreover, the drop‐casted catalyst on glassy carbon without the presence of Nafion is unable to confine significant amounts of oxygen. In contrast, the Nafion impregnated catalyst and the catalyst‐coated Nafion membrane exhibit a positive feedback response. Therefore, the oxygen is only present with the coexistence of the Nafion and the catalyst. It is suggested that the oxygen is confined within the hydrophobic part of the self‐assembled ionomer on graphitic surfaces of the catalyst's support, maintaining an equilibrium with the solvated oxygen in the electrolyte. The carbon black with two different ratios of mixed Nafion solution also presented a positive feedback response indicating that the presence or absence of Pt particles in the substrate does not interfere with Nafion self‐assembly and the consequent oxygen confinement.The catalyst, nominally 20 wt‐% Pt on carbon black was purchased from Alfa Aesar. The utilized carbon black was Timcal Super C65. Nafion 115 Dupont membrane was purchased from Ion Power and the 5 wt‐% Nafion solution was purchased from Sigma Aldrich. The Ultrapure Milli‐Q water (Millipore) and the 2‐propanol as solvent were used for ink preparation.2) and left to dry in the ambient atmosphere. A further 5 μl of the ink was dropped on top of the dried layer to reach a final concentration of 0.2 mg/cm2.The catalyst ink was prepared by adding 5 mg of 20 wt‐% Pt on carbon black to 1.3 ml of solvent containing 80 vol‐% water and 20 vol‐% 2‐propanol. The dispersion was stirred for 30 minutes followed by 15 minutes of sonication and another 30 minutes stirring to homogenize the ink. For drop‐casting, 5 μl of the ink was pipetted onto the glassy carbon  should be addressed to the authors.Supporting InformationClick here for additional data file.