The subsequent stages of the research will include the development of forming fasteners in the form of KPS-6 screws used in the steel construction industry with TRIP structures, with increased properties of products in the 8.8 property class, without conducting heat treatment by hardening and tempering. It is assumed that the resulting product will have an additional usable feature: preserving a certain amount of retained austenite in the structure of the finished fasteners, which will be transformed into martensite during operation, and thus affect the longevity of the fasteners.The research presented in this article aimed to obtain a semi-finished product in the form of TRIP wires, which in further research will be used to produce fasteners in the form of KPS-6 screws used in the construction industry. At present, the process of manufacturing this type of fastener (from wire rod to the finished product) involves two technological lines: one for carrying out the drawing process and obtaining a semi-finished product in the form of a wire with appropriate properties, and the other for the production of fasteners. Semi-finished product wires with a ferritic-perlitic structure obtained after the drawing process are the starting product for the production of fasteners, the tensile strength of which is approximately 450 MPa. In order to be able to obtain fasteners characterized by an increased level of properties in 8.8 grade, after the screw manufacturing process, heat treatment should be carried out by hardening and tempering. The new technology proposed in the article includes: a drawing wire rod with a semi-finished product diameter, two-stage heat treatment on the line for pass-through heating and cooling, ensuring the obtaining of a TRIP-type structure in drawn wires, and calibration drawing. The product of this process was a wire whose tensile strength was in the range of 700–800 MPa with a TRIP structure. Thanks to obtaining a TRIP-type structure with the assumed amount of retained austenite, we obtained wires with higher strength properties and very high plasticity in relation to wires with the same chemical composition and ferritic and perlitic structure. The research carried out in the article also allowed us to obtain, in the semi-finished product wires, a favourable relationship between the strength properties and plasticity of the material, expressed by the value of the R One of the groups of new-generation structural steels is AHSS (Advanced High-Strength Steel) ,3,4,5,6.The currently developed technologies for obtaining new-generation steel products virtually exclusively concern the rolling and cooling processes of sheet metal, while the available literature does not describe the technology of manufacturing wire rods and multi-phase steel wires with high strength properties ,22,23. SThe practically described methods of obtaining steel wires and wire rod with TRIP effect are missing in the available literature. Since 2005, a team of scientists from the Częstochowa University of Technology has been the first in the world to undertake research on using TRIP steel for wires and wire products. Basic research carried out under two research projects made it possible to solve the assumed research problems and resulted in many publications ,27,28,29Hence, a device had to be built for carrying out a two-stage heat treatment of the TRIP-type for wires up to 5.50 mm diameter, to obtain a semi-finished product for the production of fasteners with a large amount of mechanically stable retained austenite (≥60× % C) in steel preserved in the structure, which will be used in subsequent technological operations. The authors aimed to develop two kinds of technology: technology for conducting two-stage heat treatment of TRIP wires up to 5.50 mm diameter for obtaining a TRIP structure. Thanks to this technology, wires with the assumed amount of retained austenite in the structure could be obtained with increased strength properties, constituting a semi-finished product for the production of KPS-6 fasteners used in the construction industry.Another goal of the authors was to develop technology for the production of steel fasteners with a TRIP effect with increased properties placed on products in the 8.8 grade without conducting heat treatment by hardening and tempering. The results of the research on the development of technology for the production of fasteners will be the subject of another study.Properly selected chemical composition of steel is an indispensable condition for producing steel products with the TRIP effect. The carbon contents should not be too high, because carbon can be a significant influence on retained austenite stabilization at ambient temperatures. It can cause the transformation of retained austenite into martensite during cold plastic working processes. Adding proper alloying elements such as silicon (Si) and manganese (Mn) also play a very important role in TRIP steels ,31,32. STests of obtaining wires involved the use of a demonstration line to carry out the two-stage process of the TRIP type, which was constructed and developed in industrial conditions, at Metalurgia S.A. Radomsko. According to the results of the research, a semi-finished product could be obtained in the form of TRIP wires with a sufficiently high content of mechanically stable retained austenite, characterised by an increased level of mechanical properties while maintaining adequately high plastic properties.The chemical compositions of the tested steels are presented in The tests included carrying out an initial drawing process of a wire rod with a ferritic–perlitic structure and a diameter of 5.50 mm on a wire with semi-finished product diameters of 5.00 and 4.80 mm, which was then subjected to a two-stage heat treatment process of TRIP types. Subsequently, the heat-treated wires were subjected to a calibration drawing process with a diameter of 4.55 mm in order to prepare the semi-finished product for the production of fasteners in the form of KPS-6 screws used in the construction industry. The test diagram is shown in The process of drawing a 5.50 mm TRIP steel wire rod on semi-finished product wires with diameters of 5.00 and 4.80 mm was carried out in industrial conditions on the BS700 DRAWING machine. In the process, cone pullers made of sintered carbides with a drawing angle of 2α = 12° were used. The drawing process was carried out at a drawing speed of 6.0 m/s. Subsequently, wires with a ferritic–perlitic structure and semi-finished product diameters of 5.00 and 4.80 mm were subjected to a two-stage heat-treatment process in order to obtain a TRIP-type structure. For steel in grade S355J2, two diameters of semi-finished product wires were analyzed: 4.80 mm (variant No. 3) and 5.00 mm (variant No. 2), while for steel in grade G4Si1, tests were carried out for a diameter of 5.00 mm (variant No. 1).(a)A passive disc unwinder with a friction brake with adjustable clamping force of the rotating disc, which reduces excessive wire overhang during the unwinding process;(b)An arrangement of drawing rollers with individual drive and a set of stress-relieving rollers mounted in two planes, which reduce the intrinsic stresses of the wire;(c)An induction coil capable of achieving the required temperature (850 °C) in less than 5 s;(d)A high-temperature pass-through furnace No. I (850 °C);(e)A through cooler with adjustable compressed air blow to achieve the required cooling speed;(f)A low-temperature pass-through furnace II (440 °C);(g)A winder with a smooth adjustment of the rotational speed of the drum with a diameter of 1000 mm.Tests of obtaining wires involved the use of a demonstration line to carry out the two-stage heat-treatment process of the TRIP type, which was constructed and developed in industrial conditions, at Metalurgia S.A. Radomsko. The line consisted of:The diagram of the process line is shown in As part of the research, technological tests were carried out using a demonstration line to carry out two-stage heat treatment of the TRIP type in order to determine the production readiness of each of the heating zones, ensuring the required temperatures and the appropriate cooling speed were achieved; that is, the parameters that determine the TRIP structure being obtained. Induction heating tests of the previously prepared wire were carried out with a throughput speed of 6.7 and 8.9 cm/s for diameters of 4.8 and 5.0 mm. The conducted heating tests confirmed the achievement of the set temperature (850 °C) in the assumed time of less than 5 s. Tests of heating in the two-phase range by retaining elements in the working area of the furnace No. 1 were also carried out. Tests of the cooling zone efficiency from the heating temperature to the bainitic transformation temperature were carried out. The obtained results confirmed the effectiveness of the accelerated cooling zone in the range of 30–50 ºC/s. As part of the assessment of the efficiency of the demonstration line, tests were also carried out to confirm the stability of the temperature in the range of bainitic transformation temperatures for the working area of furnace II.After reaching the production readiness of the technological line for two-stage heat treatment of the TRIP type, tests were carried out for two steel grades: for steel in the S355J2 grade, two diameters of semi-finished product wires were analyzed: 4.80 mm (variant No. 1) and 5.00 mm (variant No. 2), while for steel in the G4Si1 grade, tests were carried out for a diameter of 5.00 mm (variant No. 3).On the basis of the chemical composition of the tested steels, the temperature ranges in which phase transformations take place were determined  using CTThe subsequent research stage included carrying out the calibration drawing process for wires with a TRIP structure and diameters of 5.00 and 4.80 mm for the final diameter of 4.55 mm, which is the output dimension for the semi-finished product: wires with a TRIP structure used to produce fasteners in the form of KPS-6 screws used in the construction industry. The calibration drawing process was carried out on the JP600 drum drawing machine. In the process, cone pullers made of sintered carbides with a drawing angle of 2α = 12° were used. The drawing process was carried out at a drawing speed of 1.6 m/s. The wires were pulled in one calibration drawn. The wires with a diameter of 5.00 mm were pulled to the final dimension of 4.55 mm with a single crush equal to 17%. On the other hand, wires with a diameter of 4.80 mm were pulled to the final dimension of 4.55 mm, with a single crimp equal to 9.9%.The aim of the research carried out in the thesis was to obtain a semi-finished product in the form of TRIP wires constituting the starting material for the production of fasteners in the form of KPS-6 screws used in the construction industry. These wires should have an appropriate content in the structure of mechanically stable retained austenite, which will be used in subsequent technological stages regarding the production of fasteners and should have increased values of strength properties with high plastic properties in relation to wires with a ferritic and perlitic structure.Respectively, the wires after each technological operation were placed under tests of mechanical properties. Tests of mechanical properties of drawn and heat-treated wires, after each stage of the technological process, were carried out in accordance with PN-EN ISO 6892-1:2010 on the Zwick/Z100 strength machine.Metallographic tests were also carried out. These tests consisted of the analysis of the structure of heat-treated wires using the JEOL 2100 Plus electron microscope, confirming the presence of retained austenite in the structure of heat-treated wires.The amount of retained austenite in the structure of heat-treated wires was determined using three methods. In order to determine the phase composition, a metallographic analysis of the obtained structures was carried out with optical microscopy with an Axiovert 25 optical microscope and the Veeco Multimode V atomic force microscope, and structural components were identified in heat-treated samples according to various variants.The amount of retained austenite in the wires was also determined with X-ray diffraction using the Bruker D8 Advance X-ray diffractometer.Retained austenite in the form of "free" individual grains occurred in the analyzed steels in a small amount. Retained austenite may be present in some small volume in the mixture with other phases in the form of so-called martensitic–austenitic islands or martensitic/bainitic–austenitic islands.Hence, in order to confirm the presence of retained austenite in the structure of heat-treated wires, qualitative tests of the sample microstructure were carried out with a JEOL 2100 Plus transmission electron microscope. Samples in the form of thin films obtained by electrolytic etching in a two-stream Struers Tenupol VII shaper were tested.The test results are presented in In In In From the presented test results, it should be concluded that the two-stage heat treatment process of the TRIP type, carried out in accordance with the parameters set out in The amount of retained austenite in the structure of heat-treated wires was determined using three methods.The one method was to determine the phase composition of materials by using optical microscopy with Axiovert 25 optical microscope. In order to extract retained austenite in the structure, the digestion of heat-treated samples was carried out with 2.5% nital solution, and next with 10% sodium metabisulfite solution . Thanks The volume share of retained austenite in the structure of heat-treated wires was calculated in accordance with three metallographic methods used for quantitative analysis: the point method, the incision method and the MET-ILO computer program, while in The other method used in the research to determine the amount of retained austenite in the structure of heat-treated wires was the research carried out with the atomic force microscope.2 were scanned with a Veeco Multimode V atomic force microscope. After obtaining an image in the semi-contact mode showing topographic (high) differences, it was processed in order to quantify the elements at a height. They were quantified into 10 classes marked with colours. In the subsequent step, the colour palette was edited to increase contrast and eliminate the divisions. The editing with the use of a colour palette consisted of its selection in such a way as to clearly separate the separations (of high height) and ferritic areas—the most etched (the lowest). After this operation, the colour mask for the analysis was downloaded with Corel Photo Paint X7. The mask saved in this way was developed by Image Analysis Pro in order to eliminate artefacts: single pixels, holes, etc. After preparing the image, the surface share of retained austenite in the structure of the tested samples was determined. In A fragment for inclusion was taken from each sample. Then, polishing was carried out on diamond paste. To avoid oxidation of the surface after polishing, the samples were immediately etched in nital  for 15 to 17 s. This reagent digests morphological components at different speeds; ferrite is etched the fastest, followed by bainite and martensite, while austenite is the slowest. Carbides remain almost non-etched. With a scanning microscope with a probe, after etching, the individual phases may be inferred based on their height. The excretions were visible as the highest points due to their very weak reaction with the reagent. Hence, individual structural components may be distinguished, and their contributions may be quantified. To this end, areas with an area of at least 2500 μmThe amount of retained austenite in the structure of heat-treated wires was also determined with X-ray diffraction.The measurement was performed in accordance with the Bragg–Brentano method on the Bruker D8 Advance X-ray diffractometer for the account ranging from 20 to 110 degrees. Copper lamp and CuKα radiation were applied. The measurement was carried out every 0.02 degrees. The analysis was carried out in accordance with the Rietveld method, assuming the existence of two phases of ferrite and austenite. In Tests of the amount of retained austenite in wires with different heat-treated diameters with different process parameters allowed us to determine the effectiveness of individual zones of the demonstration line, especially the accelerated cooling zone.The study aimed to obtain wires with the maximum possible content of mechanically stable retained austenite in the structure, which will be used in subsequent stages of manufacturing fasteners. According to the literature data, a two-stage heat treatment TRIP in laboratory conditions may yield up to 10% of retained austenite for each 0.1% C with a properly conducted process.The authors’ assumption was to obtain, in wires, a multiphase TRIP-type structure with retained austenite in the amount of ≥60×% C in steel, because the process was carried out in industrial conditions featuring a high variability of factors influencing the achievement of the assumed structure.For S355J2-grade steel, an average of over 11% of retained austenite was obtained in the structure of wires with a diameter of 4.80 mm and about 11% for wires with a diameter of 5.00 mm. Hence, the adopted preliminary assumptions have been met, because the steel in the S355J2 grade contains 0.18% C.For steel of G4Si1 grade, an average of about 7% of retained austenite was obtained in the structure of wires with a diameter of 5.00 mm. Hence, the adopted preliminary assumptions have been met, because the steel in the G4Si1 grade contains 0.08% C.The mechanical properties of the wires were examined at several stages of wire production: after the pre-drawing process before the two-stage heat treatment process of the TRIP type, after the two-stage heat treatment process of the TRIP type, and after the calibration drawing process. The test results are shown in e to Rm was sufficiently low; that is, the semi-finished product in the form of TRIP wires, has a sufficiently large plasticity reserve, which can be used to properly shape the product—mounting screws—in the process of fastening the head and rolling the thread. The retained austenite identified in the structure of the tested wires is absolutely responsible for the situation; it clearly affects the increase in plasticity in relation to the starting material, resulting in a two-fold increase in the value of A50, which was recorded during the wire stretching test after two-stage heat treatment. The Re value remains at a similar level as for the starting material, but it clearly increases Rm, which is related to the change in the morphology of the structure and the increase in the dispersion of structural components of the tested wires. The execution of the calibration sequence inevitably leads to the occurrence of the transformation of retained austenite into martensite in the structure; the effect of this process becomes noticeable in the results of both Rm and Retests. Both strength parameters clearly increase the values; while in the case of Rm this increase was about 100–150 MPa, the increase in Re ranged from 200 to 280 MPa.The analysis of the results of the tests of mechanical properties of the semi-finished product—that is, TRIP wires—allows us to state that as a result of the heat treatment and the process of initial reinforcement of wires in the calibration drawing process, a semi-finished product with an increased level of mechanical properties was obtained in relation to wires with a typical ferritic and perlitic structure. The values of tensile strength were about 100 MPa higher. However, an increase in the plasticity of the material was found, which was caused by the presence of retained austenite in the structure of TRIP wires. The ratio of R50 at a similar level, whereby joint products may be shaped by thread rolling and shaping the screw head.The conducted process, consisting of two-stage heat treatment and a calibration sequence, leads to an increase in strength properties in selected steels, but what is particularly interesting is that it maintains the recorded elongation of ABoth of these operations will result in a further increase in mechanical properties and a product showing the level of mechanical properties specified for fasteners in property class 8.8 without thermal treatment by hardening and tempering.The applied parameters of the two-stage TRIP heat treatment process on the demonstration line for the analyzed steel grades allowed us to obtain wires with up to 5.50 mm diameters with a volume fraction of retained austenite in the structure, meeting the assumed requirements: ≥60×%C in steel.Wires after TRIP-type heat treatment process have higher values of tensile strength in comparison to unheated wires with ferritic–pearlitic structure.e/Rm at the level of 0.84–0.87); that is, raw material for the production of screws.The conducted two-stage TRIP-type heat treatment process and the subsequent calibration drawing process allowed us to obtain the material with an appropriate plasticity reserve (RThe successive stages of shaping the screw in the plastic deformation processes will result in the transformation of the retained austenite into martensite, which will increase the mechanical properties and obtaining a fastener in property class 8.8 without conducting heat treatment on the finished product.The techniques of determining the share of retained austenite used in the presented work, both stereological and X-ray structural methods, offer high consistency in the obtained values and can be used interchangeably.The applied parameters of the two-stage TRIP type heat treatment process allowed us to obtain a material with 11% of the volume fraction of retained austenite in the structure for steel grade S355J2 and 7% for steel grade G4Si1.A technological line developed in industrial conditions for conducting a two-stage TRIP heat treatment process for wires with diameters below 5.50 mm gives the possibility of producing semi-finished products, such as wires for ropes used in the construction of protective barriers on motorways.


Skin diseases and disorders have a significant impact on people’s health and quality of life. Current medical practice suggests different methodologies for detecting and diagnosing skin diseases and conditions. Most of these require medical tests, laboratory analyses, images, and healthcare professionals to assess the results. This consumes time, money, and effort, and the waiting time is stressful for the patient. Therefore, it is an essential requirement to develop a new automatic method for the non-invasive diagnosis of skin diseases and disorders without the need for healthcare professionals or being in a medical clinic. This research proposes millimeter-wave (MMW) radiometry as a non-contact sensor for the non-invasive diagnosis of skin diseases and conditions. Reflectance measurements performed using 90 GHz radiometry were conducted on two samples of participants; sample 1 consisted of 60 participants  with healthy skin, and sample 2 contained 60 participants  suffering from skin diseases and conditions, which were: basal cell carcinoma (BCC), squamous cell carcinoma (SCC), burn wounds, and eczema. Radiometric measurements show substantial differences in reflectance in the range of 0.02–0.27 between healthy and unhealthy regions of the skin on the same person. These results indicate that radiometry, as a non-contact sensor, can identify and distinguish between healthy and diseased regions of the skin. This indicates the potential of using radiometry as a non-invasive technique for the early detection of skin diseases and disorders. Itsn adults ,4. Humann adults . Therefon adults  as well The World Health Organization (WHO) indicates a dramatic increase in the number of cases of skin cancers over the past few decades . The orgCurrent medical practice for diagnosing non-melanoma skin cancers is based on a biopsy ,11, whicThe millimeter-wave (MMW) band of the electromagnetic spectrum ranges from 30 GHz to 300 GHz ,14,15. IResearchers in ,17,24,25Millimeter-wave radiometry  was used to measure the signature of the skin  for the purposes of security screening  and mediThis section presents the background and reviews the state of the art of millimeter-wave technology in the non-invasive diagnosis of diseased skin; the following sections of the paper are structured as follows: This section presents the methodology used to measure the reflectance of human skin using a non-contact sensor (radiometry). The measurements were conducted in two groups of participants; group 1 included healthy participants, and group 2 comprised participants with eczema, malignancies, and burn wounds. Detailed information about the two groups of participants is given in The reflectance measurements in this research were applied to healthy and unhealthy skin. Detailed descriptions of the two groups of participants are provided in the following sections.The measurements of healthy skin were conducted on 30 males and 30 females with no history of skin diseases or conditions. The participants’ ages ranged from 20 to 70 years. The means and standard deviations were 1.63 ± 0.1 m for height and 70.1 ± 11.54 kg for mass. The ethics application for this research was reviewed and approved by the ethics committee of Manchester Metropolitan University (MMU) under ethics reference number SE1617114C. A written consent form was signed and approved by each participant before conducting the measurements.Sixty participants with different types of skin conditions and diseases in both genders  were recruited and measured in this research. The participants were divided into six groups, with each group containing 10 participants : (1) participants with first-degree burns, (2) participants with second-degree burns, (3) participants with third-degree burns, (4) participants with skin SCC, (5) participants with BCC, and (6) participants with skin with eczema. The participants’ ages ranged from 20 to 70 years. The means and standard deviations of the height and weight of participants were 1.61 ± 0.085 m and 68.1 ± 8.75 kg, respectively. The ethics application for this research was reviewed and approved by the ethics committee of Manchester Metropolitan University (MMU) under ethics reference number SE1617114C. A written consent form was signed by each participant before conducting the measurements.The reflectance measurements of healthy skin were performed on nine locations: (1) the palm of the hand, (2) the back of the hand, (3) the side of the inner wrist, (4) the middle of the inner wrist, (5) the outer wrist, (6) the dorsal surface, (7) the volar side of the hand, (8) the elbow, and (9) the finger region. For unhealthy participants, the measurements were performed on an unhealthy skin region . Then, the measurements were compared with the reflectance of the closest region of healthy skin in the same participant. The measurement locations for unhealthy skin were chosen based on where the skin conditions or diseases appeared and where participants felt comfortable performing the measurements, such as the forearm, leg, neck, and face regions.A radiometer with a center frequency of 90 GHz and a bandwidth of 20 GHz  was used to measure the skin reflectance. The reflectance measurements in this research were applied to healthy and unhealthy skin. The radiometer consisted of two parts, namely: the transmitter and receiver sides, as described in The horn antenna had a center frequency of 90 GHz and a bandwidth of 20 GHz . The antenna had a rectangular aperture of 30 mm × 25 mm and a nominal gain of 20 dB. During the experiment, the horn antenna was fixed to measure emissions from the target area of the skin and from hot and cold calibration sources. The voltage level of the emission from the target area of the skin was obtained from a distance of 5.0 cm from the skin sample and calibration sources. This distance was chosen as an optimal distance to minimize the chances of subjects accidentally touching and moving the measurement apparatus. A greater distance between the measured subject and the horn antenna would lead to measurements with a poorer spatial resolution .The radiometer was calibrated using two pieces of carbon-loaded foam absorbers in liquid Nitrogen  and ambient temperature . The two pieces of carbon-loaded foam absorbers  had a rectangular shape and dimensions: length = 180 mm, width = 140 mm, and thickness 10 mm. These dimensions were chosen because they are able to fill the horn antenna beam pattern and reduce the systematic uncertainty during the measurements.An infrared thermometer  was chosen to measure the temperatures of the target area of the skin and the calibration sources. This device was selected because the measurements were performed on healthy and unhealthy regions of the skin, so it is essential to obtain the temperature of the skin in a non-contact manner without touching the affected area of the skin.After measuring the voltage levels and temperatures of the skin and calibration sources, the reflectance of the skin can be obtained using Equation (1). For further information about the derivation of Equation (1), readers can refer to .(1)R=TSThe methodology for processing and collecting data is divided into four steps. Step 1 was device calibration and testing, in which two samples of foam absorbers  were used to calibrate the radiometer. Then, standard samples with known reflectance, such as a metal plate, were measured. In step 2, the target area of the skin was located 5.0 cm from the horn antenna of the radiometer. This distance was chosen as an optimal distance to minimize the chances of subjects accidentally touching and moving the measurement apparatus. Then, an infrared thermometer and digital voltmeter were used to measure the temperature and voltage level of the thermal emission, respectively. In step 3, Equation (1) was used to convert the temperature and voltage measurements into reflectance. All data were saved as Excel files, and Python software was used to process and visualize the data. In step 4, a similar methodology was applied for unhealthy skin regions, except for conducting measurements on both unhealthy skin and the closest healthy skin region on the same person. This section presents the reflectance measurements obtained from healthy skin and unhealthy skin.This section presents reflectance measurements of healthy skin regions. The reflectance measurements of a sample of 60 healthy participants  in This section presents reflectance measurements performed on burned skin regions, skin with SCC, skin with BCC, and skin with eczema.The reflectance measurements in The experimental measurements in The radiometric measurements in The experimental measurements of healthy skin and skin with squamous cell carcinoma in The reflectance measurements of healthy skin and skin with basal cell carcinoma in The experimental measurements for healthy skin and skin with eczema in The reflectance measurements in this research confirm substantial differences in reflectance between healthy and unhealthy regions of the skin. This indicates that reflectance measurements can be a good indicator of the health status and disease risk of the skin. The key innovation is the introduction of millimeter-wave radiometry as a non-contact sensor for the non-invasive diagnosis of diseased skin and for the early detection of skin diseases and disorders.The reflectance measurements of healthy skin regions in The reflectance measurements of healthy and burned skin regions in The experimental results for skin cancers in The radiometric measurements in Radiometric measurements of human skin over the microwave and millimeter-wave bands are very sensitive to variations in water content and skin thickness ,26. RadiThis paper presents reflectance measurements performed on a sample of 120 participations . The measurements were performed using millimeter-wave radiometry at a center frequency of 90 GHz. For the healthy skin group , the measurements were conducted on nine locations on the hand: (1) the volar side of the hand, (2) the dorsal surface of the hand, (3) the elbow, (4) the palm of the hand, (5) the back of the hand, (6) the finger region, (7) the inner wrist (middle region), (8) the inner wrist (side region), and (9) the outer wrist region. The measurements show different ranges of reflectance for different locations and genders. In addition, exceptional data points (outliers) reflect the state of health and the weight of the participants. For the unhealthy skin group , reflectance measurements were performed on diseased and healthy skin regions of the same participants. The measurements indicate substantial differences in reflectance of the skin between healthy and unhealthy regions, namely: burn wounds, skin with BCC, skin with SCC, and eczema. These findings indicate the potential for using radiometry to detect skin diseases, disorders, and conditions, as it provides a robust testing platform without touching the skin (non-contact mode). The next step of this research is to conduct more reflectance measurements in a more diverse population with healthy and diseased skin in both genders and then use these measurements to perform gender-based comparisons, as well as build machine learning algorithms for the automatic detection and prediction of human skin diseases and disorders.


Due to its extreme service conditions, low-temperature pressure piping often needs post-welding stress measurement and control. Aiming at the phenomenon of local stress concentration in welded 316L pipes, this study used ultrasound to regulate the stress in the welded area at different times during and after the multi-layer welding of the pipeline butt joint for different time lengths. Mechanical properties such as tensile strength and hardness were tested for each comparison group, and the microcrystalline phases of the weld and its surrounding microstructure were analyzed. The transverse and longitudinal surface residual stresses of each comparison group were measured. The influence of high-energy ultrasound on the surface temperature field during and after welding was analyzed. The experimental results show that ultrasonic wave regulation can speed up heat exchange and radiation in the weld zone (WZ), refine the grains in the WZ, heat-affected zone (HAZ) and fusion zone (FZ) to some extent and reduce and homogenize residual stress to a certain degree. In the 120 mm area of the weld center, the residual stress measured after the mid-welding regulation was smaller than that of any other comparison group. This regulation result was the best, followed by that of hot regulation and finally that of offline regulation. The tensile strengths obtained by the mid-welding regulation and post-welding hot regulation of this group were the best, increasing by 17.2% and 24.3%, respectively, compared with the untreated groups. In industrial fields such as marine, shipping and nuclear power, 316L low-temperature pressure piping is often faced with fatigue failure, stress corrosion, fractures and other problems ,8,9,10. For 316 stainless steel, Shalvandi et al.  comparedSome scholars also studied the effect of ultrasound on melted or cooled solids to improve the microstructure properties according to the effect of ultrasound on the physical state of welding. Dehnavi et al.  found thAlthough many studies have been carried out in recent years on the application of ultrasound in solid and molten metal materials, most of them are still limited to the single properties of specific samples, such as yield stress, residual stress and material microstructure, without comprehensive research on the mechanisms of specific stress regulation, stress distribution and multi-physical-field coupling, and mechanical properties and microstructure properties for the multi-layer bead of a tubular structure. Therefore, the foundation for further large-scale applications of this technology in general manufacturing fields such as welding and machining cannot be laid.In order to deeply study the influence of ultrasound on the multi-layer welding process of a 316L pipe and on its post-welding microstructure properties and residual stress, ring-shaped array ultrasonic waves were applied to base metal in this study by changing the regulation duration in the offline mode and the regulation timing in the online mode. The mid-welding and post-welding regulation of welds were carried out. The microstructure properties, mechanical properties and stress relief results that were obtained with different treatment methods were studied and compared. The law of temperature field distribution in different treatment methods was analyzed to further reveal their residual-stress relief mechanism. This study provides a technical basis for realizing the low stress manufacturing of stainless steel butt joints through gas tungsten arc welding (GTAW) with high efficiency and low cost.The base metal (BM) used in the test was a 316L butt-welded seamless stainless steel pipe with a 168 mm diameter, an 8 mm wall thickness and a 600 mm length. Double The test system in this paper consisted of an automatic robot welding system, an ultrasonic wave system and a flexible clamping system. The robot welding system used a KUKA KR16 six-axis industrial robot  and a Fronius Trans Tig 5000 Job G/F TIG power supply. The ultrasonic wave system used a NYK5887-L6 power amplifier with continuous output power up to 800W and an output frequency range of 100 Hz–100K Hz. In the system, a RIGOL DG1022 dual-channel function/arbitrary waveform generator was used, with the highest sampling frequency of 100MSa/s. Six groups of circumferential array high-energy ultrasonic exciters were designed. The ultrasonic transducer waws a PZT4 piezoelectric ceramic transducer with a diameter of 70 mm and a resonant frequency of 14.64 kHz. The distance between the transducer and the weld center could be adjusted. To facilitate the comparison of regulation effects, all the transducers in this study were arranged on side A, 130 mm away from the weld center, as shown in The system was designed with two high-energy ultrasonic excitation schemes, namely a mid-welding online scheme and a post-welding offline scheme, as shown in As the GTAW used in this study had a small filling capacity, the four-layer bead technique was selected to complete the backing welding, filler welding and cosmetic welding of the bead. The relevant process parameters are shown in 0, was conventional gas metal arc welding(GMAW) without the application of ultrasound. The second group, defined as U1, was GMAW followed by 1 h of cooling and then 1 h of the application of high-energy ultrasound (U-GTAW-C1). The third group, defined as U2, was GMAW followed by 1 h of cooling and then 2 h of the application of high-energy ultrasound. The fourth group, defined as U3, was the 10 min regulation of each of the 2–4 bead layers during welding, with 0.5 h of the application of ultrasonic excitation. The fifth group, defined as U4, was post-welding hot regulation, i.e., the 10 min regulation of each of the 2–4 hot layers for a total of 0.5 h. Among them, the group U0 was without ultrasonic application, the groups U1 and U2 were with offline ultrasonic application and groups U3 and U4 were with online ultrasonic application, as shown in To study the regulation effect of ultrasonic waves on the residual stress, mechanical properties and microstructure of 316L stainless steel, five groups of welding samples, as shown in To ensure the validity of the comparison sample data, the 0° starting points and circumferential 330° points of the above five groups of welding samples were selected as the sampling center points of tensile specimens and metallographic specimens. The shape and specifications of the specimens are shown in 0 showed the microstructure of the weld zone without ultrasonic treatment, which was basically composed of long and coarse columnar crystals growing from the weld fusion line to the center. The groups U1 and U2 show the microstructures obtained after 1 h and 2 h for post-welding ultrasonic regulation, which revealed no obvious influence of ultrasonic regulation on the weld grains. The group U3 and U4 showed the microstructural morphology under the mid-welding regulation and post-welding hot regulation. It can be seen that, under the action of ultrasound, the size of columnar crystal zones was significantly reduced, the columnar crystal roots along the radial and axial directions were clearly refined and equiaxed dendritic crystals existed between the columnar crystal zones.The grain morphology of the five groups of weld samples is shown in 3 and U4, it can be seen that, under the mid-welding regulation, the columnar crystal zone of the weld was the least obvious, and the proportion of the equiaxed dendrite crystals was the largest. This is because the application of high-energy ultrasound in the welding process brought the acoustic flow effect [By comparing Uw effect  and ultrw effect ,37, whicw effect .0, the matrix was composed of austenites, and many large chain-shaped δ ferrites were found at the grain boundary. In groups U1 and U2, under the offline regulation, the large chain-shaped δ ferrites were reduced due to the introduction of high-energy ultrasound. In groups U3 and U4, under the online regulation, the large ferrites were uniformly refined and dispersed to the austenite grain boundary for precipitation, and the grains were clearly refined.The microstructures of PMZs  of different comparison groups are shown in Through comparative experiments, it was found that the online regulation of high-energy ultrasound can play a role in refining the crystals in the melting zone. Due to the effect of high-energy ultrasound, the initial ferrite dendrites increase; therefore, more dendrites spread to the crystal boundary to refine the microstructure. However, under offline regulation or cold regulation, the internal stress brought by the application of high-energy ultrasound stimulates the dislocation source action in the grains, resulting in slip and then elastic deformation release and macroscopic plastic deformation. As a result, the grains are not substantially refined.0, U1 and U2 were coarse with wide boundaries. However, the grains of groups U3 and U4 were smaller with narrower boundaries and had radially decomposed equiaxed dendrites between the columnar crystals. The equiaxed dendrites in U3 had the largest number and the smallest size. This is because the mid-welding ultrasonic regulation of U3 and the post-welding hot ultrasonic regulation of U4 could accelerate the heat exchange inside and outside the microstructure and decrease the internal temperature quickly to a more balanced point; therefore, the grain refinement degree was better than that without ultrasonic treatment.High-energy ultrasound also has an impact on the morphology of columnar crystals near the weld fusion zone. As shown in 4 was the highest, the yield limits of U2 and U3 were close to each other and the yield limits of U0 and U1 were basically the same. The slopes before the inflection points were basically the same. The above results show that online ultrasonic regulation can obtain better linear elasticity by extending the elastic zone.The tensile test was carried out on the five groups of experimental samples. As the tensile strength of the BM and HAZ was much higher than that of the WZ zone, all tensile specimens were fractured at WZ. The experimental curves are shown in 4, increasing by 17.2% and 92%, respectively, over the untreated comparison group U0. However, the optimal tensile strength of 643.2 MPa and the suboptimal elongation of 35.03% were obtained by post-welding hot ultrasonic regulation, increasing by 24.3% and 88.7%, respectively, over U0. This further confirms that the strength of polycrystals increase with grain refinement degree. Based on the Hall–Petch formula [It can be seen from the tensile strengths and elongations in  formula , it can 0–U5 along their BM, HAZ and WZ zones, and then their hardness was measured by a Vickers hardness (HV) tester. The comparison results are shown in A total of 15 points were sampled from the sample groups U3 had the greatest impact on the heat-affected zone (HAZ), greatly increasing the HAZ hardness by 9.6% on average from the pre-treatment 151 HV to post-treatment 163–168 HV. The HAZ hardness of U4 (0.5 h post-welding hot regulation) increased by 4.6% on average from the pre-treatment 151 HV to post-treatment 157–159 HV. The HAZ hardness of the other two comparison groups U1 and U2 was somewhat improved, but this impact was small. The coarse columnar crystals in the HAZ were refined due to the influence of ultrasound, thus causing changes in hardness [The 0.5 h mid-welding regulation of Uhardness .1 and U2 were subjected to post-welding cold regulation, which had little effect on their WZ hardness. Their WZ hardness was generally similar to that of the control group. It can be seen from the above that the offline regulation had no obvious effect on either grain size or hardness.Groups U3 and U4) on HAZ was higher than that of the two methods of offline regulation, which indicates that the online regulation can substantially improve the mechanical properties of the material.The effect of the two methods of online regulation , existed at that time. The existence of the ultrasonic field sped up heat exchange and environmental radiation; therefore, the heat in the area near the ultrasonic field could be quickly exchanged.Compared with the control group UThe above-mentioned hot regulation and mid-welding regulation had different impacts on temperature fields and different stress regulation mechanisms. The former was to bring about local temperature rise through the coupling and superposition of heat fields and high-energy ultrasonic fields in the welding process, and the latter was to speed up heat exchange and radiation by the use of high-energy ultrasonic fields and then to improve the microstructural crystallization.0–U4 on sides A and B 20 mm away from the weld center, as compared in 0, the residual stresses on sides A and B of the pipe weld circumference were basically symmetric. The amplitudes of transverse and longitudinal residual stresses changed significantly along the circumference, which was related to weld starting position, heat input, circumferential constraint and other welding factors. Under any of the four regulation schemes U1–U4, the overall stress-relieving effect of the excitation side A was better than that of side B. The online regulation schemes U3 and U4 had the best effect on circumferential residual stress relief and homogenization. The offline regulation schemes U1 and U2 also worked, but U2 had a much better stress-relieving effect than U1.The residual stress ultrasonic detector meeting the national standard GB/T 32073-2015 was used to measure the transverse and longitudinal residual stresses of groups UThe above phenomenon appeared because the use of ultrasonic waves for online regulation improved the microstructural crystallization, refined the grains and improved the stress condition. The offline regulation caused the transformation of elastic strain in the material into plastic strain and the release of residual stress. However, since the regulatory energy attenuated with the increase in the propagation distance, there was an obvious residual stress gap between sides A and B.3 (mid-welding regulation) had the most significant stress-relieving effect, followed by U4 and then U1 and U2. From the point of view of offline regulation time, the stress reduction by U2 was greater than U1 but was not proportional to the time. This indicates that a longer regulation time can improve the effect of offline stress regulation, which, however, stops changing significantly after a certain time. Moreover, it can also be found that the stress reduction was relatively significant in the area near the weld, indicating that the regulation effect of high-energy ultrasound in the near-field region was significantly better than that in the far-field region. This effect was basically zero in the area beyond 120 mm.The transverse and longitudinal distribution of the axial residual stress is shown in 4,U5). The research conclusions can be drawn as follows:(1)Through the acoustic flow effect and ultrasonic cavitation effect, the use of ultrasonic waves for online regulation transformed the columnar crystals in the weld fusion zone into equiaxed fine crystals, increased the initial ferrite dendrites in the melting zone, generally refined the grains and improved the stress condition. However, in the use of ultrasonic waves for offline regulation, the internal stress brought by ultrasonic wave propagation stimulated the dislocation source action in the grains, resulting in slip and then elastic deformation release and stress relief. In general, the stress-relieving effect of online regulation was much better than that of offline regulation. In addition, the regulation effect of high-energy ultrasound in the near-field region was significantly better than that in the far-field region but became basically zero in the area beyond 120 mm.(2)Compared with the unregulated material, the introduction of ultrasonic waves into the online (mid-welding and post-welding hot) regulation obtained better tensile strength and elongation, which could increase by more than 80% and more than 17%, respectively. Moroever, the best grain refinement effect was obtained by online ultrasonic regulation, and a higher material surface hardness was also achieved by the grain boundary strengthening effect.(3)The two modes of online ultrasonic regulation (mid-welding regulation and post-welding hot regulation) could effectively improve the HAZ hardness of the welded material by 9.6% and 4.6%, respectively, compared with that of the untreated group. However, the offline regulation had no effect on hardness.(4)During online ultrasonic regulation, the “stirring” effect of the sound field could speed up heat exchange and radiation. When the mid-welding regulation was applied, the temperature gradient in the near-sound-field region was smaller than that in the far-field region due to the superposition of the welding heat field and ultrasonic field and the formation of a local high-temperature area. When the post-welding regulation was applied, the temperature gradient in the near-sound-field region was larger than that in the far-field region.In this study, ultrasound was applied at different times and durations before and after the welding process of 316L stainless steel to adjust the cooling and crystallization effect of the microstructure to achieve homogenization and reductions in residual stress in the weld. Through the comparison and analysis of the grain morphology of PMZ and weld fusion lines, the influence of ultrasound on the microstructure was studied. Tensile and hardness tests were carried out on five groups of comparison samples to further analyze the influence of ultrasound on the mechanical properties of the material. This study explored the effect of ultrasound on temperature fields in the microstructural crystallization process and investigated the distribution law of the surface temperature field along the weld circumference of the pipes under online regulation (U


Based on the Digital Imaging and Communications in Medicine (DICOM) data of three-dimensional magnetic resonance imaging (3D-MRI), finite element models of the hip joints of children with developmental dysplasia of the hip were established. The primary objectives included simulation and analysis of the finite element model pre- and post-closed reduction under different stances and loads, and evaluation of the size and distribution of von Mises stress in the acetabulum and femoral head pre- and post-operation and the short-term effects.Acetabular index measurements of both the unaffected and affected sides were conducted, alongside International Hip Dysplasia Institute (IHDI) classification of the affected hip. Establishing the finite element model of both the affected and unaffected hips was based on the 3D-T1WI sequence DICOM data, using Mimics, 3-matic, and Ansys software, before and after closed reduction surgery. The size and distribution data of von Mises stress on the affected side of the acetabulum and femoral head were collected pre- and post-operation.P < 0.05). Preoperative IHDI classification significantly correlated with the von Mises stress . Under different stances and load conditions, the von Mises stress on the affected side post-operation was lower than that noted pre-operation (P < 0.01), while that on the acetabulum increased proportionally to the load. Although the magnitude and distribution of von Mises stress on the affected side of the acetabulum were similar to those on the healthy side post-operation, there were statistical differences between the two (P < 0.01). The von Mises stress of the lateral column of the femoral head post-operation was significantly lower than that noted pre-operation (P < 0.01). While the high-stress points of the lateral column disappeared post-operation, the von Mises stress was evenly distributed in the femoral head.The study indicated that the increasing acetabular index of the affected hip was directly proportional to the increasing severity based on IHDI classification (The 3D-MRI finite element could provide the von Mises stress value and distribution characteristics of the acetabulum and femoral head pre- and post-operation. Closed reduction can, therefore, improve the size and distribution of von Mises stress on the affected acetabulum and femoral head. Developmental dysplasia of the hip (DDH) is one of the most common hip diseases in children. DDH includes acetabular dysplasia, hip semi-dislocation, and hip dislocation . TreatmeFinite element analysis (FEA) is a dispersion method in numerical calculations, comprising the development and application of matrix methods in the fields of structural mechanics and elastic mechanics. FEA replaces biomechanical experiments to a certain extent and can control experimental conditions and simulate the biomechanical conditions of the human body. In the biomechanical evaluation, according to the fourth strength theory, no matter what stress state, the main distortion energy density reaches a certain limit value related to the material properties, and the material will yield. Similarly, bone is prone to yield failure. At this time, Von Mises Stress can be used as the failure judgment index. Following are the basic steps for FEA: image scan, geometric model reconstruction, division finite element mesh, skeletal material attribute definition, determination of boundary conditions, load loading, and final analysis. The earliest use of 2-dimensional (2D) FEA was by Andriacchi et al. , who stuIt has been reported that the 3D-FEA simulates the absence of different DDH closed reduction outgoing abductions, observes the changes of von Mises stress in the acetabular and femoral head of the hip joint, explores the possible mechanism of AVN after closed reduction, and provides mechanical guidance for clinical surgery , 13. ThiThe medical records of DDH children in Shengjing Hospital of China Medical University from December 2019 to December 2020 were collected. All children received closed reduction treatment, and the general clinical data and MRI data were recorded. The hospital ethics committee approved this study .The inclusion criteria were as follows: 1) the age at hospitalization < 18 months; 2) closed reduction treatment under general anesthesia; 3) single side DDH; 4) MRI review 1 week after surgery. The exclusion criteria were as follows: 1) surgical treatment with reset failed; 2) DDH accompanied with AVN; 3) neuromuscular DDH; 4) incomplete imaging data (lack of preoperative or postoperative MRI examination); 5) contraindications for MRI examination; 6) no treatment or failure of Pavlik treatment before surgery..This study included 15 children (30 hips), including 3 boys (6 hips) and 12 girls (24 hips); 9 cases of the hip on the left side and 6 cases of the hip on the right side. The preoperative age of children was 4–18 months and the median age was 9 months. Body weight was 8–15 kg, with an average weight of 10.22 ± 1.91 kg.Before Pelvic MRI examination, all children were sedated and hypnotized by enema with chloral hydrate(0.05 g/kg) and physiological saline10 mL). All MR images were collected with 3.0 T magnetic resonance  and scanning with body launching and accepting coil. Conventional MRI sequences  and transverse 3D-T1WI were scanned from the anterior superior iliac spine to the center of the femoral shaft as the reference plane, and the head in supine position was advanced with keep the legs horizontal  with the H line. The International Hip Dysplasia Institute (IHDI) classification standard  is used The Digital Imaging and Communications in Medicine (DICOM) data of the affected hip 3D-T1WI were imported into the Mimics Research 21.0 software . The iliac crest, pubic bone, ischium, femoral head, and superior femoral bone, as well as the per femoral head and acetabular cartilage, were modeled by using magnetic lasso, regional growth, mask editing, and 3D model calculation. Import the 3D model into 3-material research 13.0 software  for mesh optimization to generate surface network. The optimized surface mesh is used to generate tetrahedral mesh, which is imported into FEA module, and the three-dimensional finite element model is output to ANSYS software in CDB format. In ANSYS 19.0 software, and the proximal femur was subjected to grid densification. A total of 186,351 units were generated, including 116,849 units of cortical bone and 69,502 units of cancellous bone  was used to compare the differences in hip AI between different IHDI classifications. The paired-sample t-test was used to compare (1) the von Mises stress of the iliac bone and femoral cartilage before and after the operation, (2) the von Mises stress of the iliac bone and femoral cartilage after the operation, and (3) the contralateral side. Pearson correlation analysis was used to analyze the 2-variable correlation between the preoperative IHDI classification and the von Mises stress of the acetabulum and femoral head. P < 0.05 indicates that the difference is statistically significant.SPSS 21.0 statistical software was used for data analysis, and the measurement data are presented as P < 0.05), and the II-IV type AI values were (37.60 ± 2.78)°, (42.37 ± 1.69)°, and (46.45 ± 1.10)°, respectively. Preoperative IHDI typing was significantly associated with acetabulum and femoral head von Mises stress on the affected side  of II type, 8 cases (53.3%) of III type, and 4 cases (26.7%) of IV type. The AI of affected hip increased proportionately to the increase of IHDI type (The results of von Mises stress of the acetabulum on the affected side when 1–3 times the body weight was applied to the single and double-legged standing positions are shown in Table P < 0.01). This is evident in the acetabular stress cloud map, alongside the presence of a high-stress concentration point outside the upper boundary of the acetabulum, which increases as the load increases.Although the magnitude of von Mises stress on the affected side was similar to the value observed on the uninjured side Table , there wFollowing operation, the high-stress point disappeared at the lateral edge of the upper region of acetabulum and von Mises stress distributed evenly inside the acetabulum. The stress was transmitted from the central upper region of the acetabulum to an inward and downward progression and gradually weakened radially to the periphery. This was similar to the distribution and transmission of stress on the healthy hip Figs. , 3 and 4p < 0.01).The stress of the outer column of the femoral head is higher than that of the central and inner columns. The stress of the outer column of the femoral head after surgery was significantly less than that observed preoperatively Table . AlthougAs shown in the femoral head stress cloud map, the outer strip of the preoperative femoral head appeared at a high-stress point, which corresponds to the top outer edge of the acetabulum and increased proportionately to the load. After surgery, the high-stress point of the outer column disappeared, and the femoral head Von Mises stress distributed evenly and radiated to all sides, similar to the scientific side Figs. , 6 and 7To restore the containing structure of the femoral head and acetabulum, the treatment is usually based on morphology  and biomechanics –29. In iWolff Theory indicates that bone growth is closely related to stress, and high-strength load can inhibit osteocyte activity, promote osteogenic cells, and inhibit bone growth. In addition to the literature , 35, 36,Von Mises stress of the femoral head reflected the mechanism of load transmission and mechanical stress state in the joint. Previous finite element studies , 37–40 hAt the same time, the outer column of the femoral head is the main carrier area of the femoral head, but it is in primary contact with the acetabulum. Furthermore, when the necrotic lesion involves the outer column, its mechanical carrying capacity is poor –43. Wen In this study, the abnormally high von Mises stress distribution of the lateral femoral head column was observed in all 15 patients before surgery. With increasing load, the von Mises stress of the femoral head outer column also increased, which may lead to increased pressure inside the femur and compression of the nourishing artery, thus increasing the risk of AVN and collapse of the femoral head. This has guiding significance for clinical treatment. In the stress cloud map of the femoral head after surgery, the abnormally high von Mises stress before surgery disappeared in the outer column of the femoral head, and the distribution of von Mises stress in the 3 columns of the femoral head was uniform and gradually decreased radially to the periphery. Whether in the single-legged or double-legged posture, as the load increased, there was no high-stress point in the outer column of the femoral head. Therefore, closed reduction can reduce the risk of AVN and femoral head collapse.DDH acetabular shape is shallow, resulting in insufficient coverage of the femoral head; long-term low coverage can lead to chronic overload of joint cartilage, resulting in cartridge damage, eventually leading to OA. Closed reduction, via restoration of the concentricity between the acetabulum and the femoral head, reduces the stress on the cartilage at the outer edge of the acetabulum, thereby preventing OA –48. In tThis study has the following limitations and insufficiencies. First, this study may have a risk of bias as the sample number was relatively small, and the follow-up time was short. Therefore, it is not possible to evaluate the long-term effects on the hip comprehensively and completely, post-operation. Second, the load and boundary setting conditions cannot be fully in accordance with the real situation, and the finite element model of this study is relatively simplified, as it ignores the effect of the ligament around the hip joint following loading. In addition, this study has the problem of simple modeling of cancellous bone material in the process of model establishment, so there are some limitations in the process of stress evaluation. Moreover, because the material of the model is different from that of the entity, and the biological differences of individuals are not considered, this is also the problem of other finite element models. Finally, due to the existence of triangular hyaline cartilage in infants, the MRI image data when measuring bone pressure and supine position alone do not fully reflect the stress level of pelvis, and Drucker Prager equivalent stress can be used to evaluate the stress level of bone and cartilage in further research.In this study, the FEA method was used to compare the magnitude and distribution characteristics of von Mises stress on the acetabulum and femoral head before and after the closed reduction operation. After the operation, the high-stress points on the lateral edge of the top of the acetabulum and the lateral column of the femoral head disappeared, and their stresses were uniformly distributed in a radial pattern, which gradually weakened to the periphery. The magnitude and distribution of stress achieved on the affected hip was similar to that on the healthy side. Therefore, closed reduction can improve the size and distribution of von Mises stress on the affected acetabulum and femoral head.


This research proposes an innovative design of a new cyclone mixer for the quality of polymer materials, and it presents a systematic optimization model of process parameters for plastic injection molding. Thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to determine the appropriate thermal properties of processing in order to select appropriate control factors and level values for a Taguchi orthogonal array. The injection molding machine was used to make sample test pieces for tensile strength, hardness and impact strength. Significant factors were found by the signal-to-noise (S/N) ratio with an analysis of variation (ANOVA), and the single-quality optimal parameter combination was obtained. The reproducibility of the experiment was evaluated, and various quality weights were evaluated by principal components analysis (PCA). The multi-quality optimal parameter combination was found, and the comprehensive scores were compared. Finally, the process capability indices were combined with a multi-process capability analysis chart (MPCAC) to compare the process yields of cyclone mixing and screw mixing. The mechanical properties of products were evaluated to verify the performance of cyclone mixing and to provide perfect information for the injection molding quality performance of cyclone mixing and screw mixing. It was concluded that the overall quality of the cyclone mixing products is 42.72, and the total quality of the screw mixing products is 41.85. The total number of defects for the cyclone mixing is 9659 ppm, and that of the screw mixing is 10688 ppm. It can be seen that, for the overall product quality performance, cyclone mixing can be applied in the plastic injection molding process instead of screw mixing. The development of a polymer blend is often an excellent alternative to reach the desired properties ,2. PolymInorganic fillers are widely used in the polymer industry to improve the mechanical properties of polymers. Compared with conventional composites based on micron-sized inorganic fillers, nanocomposites based on nanoscale fillers, such as silica, have attracted great attention because of their improved mechanical properties . To achi2 surface treatment on the microstructure and particle distribution of PP/SiO2 composite and found that a small amount of nano-SiO2 can enhance the strength and modulus of the composite effectively. Zheng et al. . The screw type tension prediction value S/N ratio is 31.523, and the experimental value S/N ratio is 31.526. As the difference is 0.0036, this error is in the 95% confidence interval. The rest can be deduced accordingly, and the results are shown in According to the ANOVA of screw mixing tension, the significant factors influencing the mechanical properties include (B) SiOThis section describes the combination of the Taguchi method and PCA in order to obtain the comprehensive appraisal value of the processing parameters. Step 1: The S/N ratio data of the three mechanical properties, tension, hardness and the impact of screw mixing and cyclone mixing, are integrated. Step 2: The S/N ratio data of each quality are standardized with Equation (10) to obtain the standardized data. Step 3: The standardized data are calculated with Equation (11) to find the matrix of the correlation coefficient of various qualities, as shown in Step 4: The eigenvalues and eigenvectors of the parameters are calculated according to the correlation coefficient in 2 content of 5%, a melting temperature of 170 °C, a packing pressure of 80 kg/cm2, a packing time of 0.5 s, a shot pressure of 60 kg/cm2, an injection speed of 50 mm/s and a cooling time of 15 s. Cyclone mixing is A2, B2, C1, D1, E3, F1, G1 and H1, which are a feed rate of 60 rpm, a SiO2 content of 3%, a melting temperature of 170 °C, a packing pressure of 40 kg/cm2, (E) a packing time of 1.5 s, (F) a shot pressure of 40 kg/cm2, (G) an injection speed of 30 mm/s and a cooling time of 10 s.The control factors with a higher score are conditions with significant influence, and the combination of the optimal conditions is the multi-quality optimal parameter group. The results are shown in Afterwards, the optimization parameters were adopted in the experiment, as shown in To measure the influence of the multi-quality parameters on the process, PCA can effectively find the weight ratio of each variation, calculate the quality variation contributions and comprehensive score coefficients and find an effective correlation of various process qualities when calculating multivariable data, which is a method used to measure the weight of the multi-quality parameters. The quality variation contributions and the rotated component matrix of cyclone mixing and screw mixing under multi-quality parameters were calculated by PCA. The relationship between the eigenvalues and the variance was calculated with Equation (12) to find the linear combination coefficients of various principal components, as shown in After summing the linear coefficients and eigenvalues of the principal components, the comprehensive weight ratio was obtained, as shown in pm of PCI in this section in order to discuss whether cyclone mixing can maintain a high product yield with a relatively high product quality performance. The target value was regarded as the midpoint of the specification limit [The subsequent product quality stability of cyclone mixing and screw mixing was measured by using the Con limit , and tenThe quality data in pm represents a quality process. This research employs six sigma to analyze the product yield of cyclone mixing and screw mixing, and the instability of the two processes was analyzed by using the yields. The relationships of accuracy and precision to the Cpm value are found through Equation (19), and the defect rate corresponding to each important quality is calculated by Equation (15), as shown in Each coordinate point  of the cyclone type and the screw type of MPCAC/CThe cyclone mixer can be directly placed on the injection molding machine, and mixing and injection are combined to form an integral process. With the conical shape of cyclone mixing, the air spins fast along the end wall; therefore, the material is collected downwards and is mixed. For screw mixing, the material is molten from cavity heating, extruded through the die orifice, cooled and cut into mixed particles. The twin-screw mixer needs to preheat for 2 h in advance, and then it takes almost an hour for the whole procedure. After that, the pellets are left for a minimum of 8 h to allow them to solidify before being inserted into an injection molding machine. If we consider the total overall mixing and processing time for the twin-screw to be about 11 h, it is a drawn-out and time-consuming procedure for the twin-screw mixer.For cleaning after mixing, some components of the cyclone mixer, such as the feed pipe, conical cavity and feed screw, are easy to assemble and disassemble and can be detached and cleaned. This is better than conventional screw mixing, which consumes a lot of raw materials for the cleaning step. The cleaning of the cyclone mixer is more complete, and the consumption of raw materials is low.A comparison of the injection molding quality performance and process capabilities between cyclone mixers with innovative designs and conventional screw mixing is presented in this study via the application of polypropylene /silicon dioxide composites.2 content of 5%, (C) a melting temperature of 170 °C, (D) a holding pressure 80 kg/cm2, (E) a holding time of 0.5 s, (F) an injection pressure of 60 kg/cm2, (G) an injection speed of 50 mm/s and (H) a cooling time of 15 s. The best parameter group for multi-quality cyclone mixing is as follows: (A) a feeding speed of 60 rpm, (B) a SiO2 content of 3%, (C) a melting temperature of 170 °C, (D) a holding pressure of 40 kg/cm2, (E) a holding time of 1.5 s, (F) an injection pressure of 40 kg/cm2, (G) an injection speed of 30 mm/s and (H) a cooling time of 10 s. The quality measurement values of the best multi-quality parameter products are all close to the quality measurement values of each best single-quality parameter product. Then, through principal component analysis, three quality weights of impact and hardness are evaluated, and it is concluded that the overall score of cyclone mixing is 42.72 and that the overall score of screw mixing is 41.85. The cyclone mixing has a better overall mechanical property quality performance than that of screw mixing. The total number of defects of cyclone mixing is 9659 ppm (parts per million), and that of screw mixing is 10688 ppm, which shows that the overall product quality performance of cyclone mixing is better than that of screw mixing. The injection molding quality performances and process capabilities between cyclone mixers with innovative designs and conventional screw mixing are presented in this study via the application of polypropylene /silicon dioxide composites.The Taguchi method and the principal component analysis method are combined to find the best multi-quality parameter group. According to the parameters, it can be concluded that the best parameter group of multi-quality screw mixing is as follows: (A) a feeding speed of 40 rpm, (B) a SiO


Depending on the fibers’ type, the surface soundness can vary between 0.7 N mm−2 and 1.2 N mm−2. Five-layer panels were of similar or even higher parameters, but due to much-complicated technology, it seems unreasonable to develop this type of composite. The novelty of the conducted research is the attempt to modify the structure of particleboards by adding various amounts of two different types of fibers by mixing them with particles or adding them as separate layers and producing panels of different densities.One of the ways of potential improvement of the particleboard properties, especially surface quality, can be the incorporation of wood fibers to face layers. This study aimed to evaluate the selected mechanical and physical parameters of single and multi-layered particleboards with the structure modified by the incorporation of various types and amounts of wood fibers. Single, 3- and 5-layers particleboards were produced with two different types of wood fibers added to the face and core layers. The basic mechanical parameters , as well as density profile and surface roughness, have been investigated. The results have shown that the single-layer panels with fibers did not meet the standard requirements due to unsatisfactory unstable parameters, probably caused by uneven resination. The remaining panels, 3- and 5-layer, met the standard requirements, and, due to fiber incorporation, there is also potential to reduce the panel density, still meeting standard requirements. The addition of fibers from 0% to 75% in face layers leads to an increase in the modulus of rupture from 10.6 N mm In addition, the surface roughness, characterized by Ra, has risen from 2.04 μm to 4.91 μm under the same moisture content change. The importance of the moisture influence of the panels covered by fibrous materials has also been confirmed by Ulker [The use of thin overlays, like various laminates, melamine-impregnated papers, etc., to cover and finish the particleboards’ surface, forces to keep the surface finished, with high parameters, especially roughness. The quality of the final processed wood-based panel can also be influenced by machining parameters , as wellRegarding the surface roughness of fibrous panels for the furniture industry (MDF), not only the surface structure can influence the surface roughness. The results  show tha2 nanoparticles deposition on MDF panels [The surface properties of fibrous wood-based composites can be influenced not only by the use parameters but can be created during panel production. The results of the roughness measurement of MDF produced from fibers impregnated by selected boron-based chemicals have shown that the roughness values of the samples increased with increasing chemical concentration used during panel manufacturing . The useF panels . The parF panels , the addF panels . The panF panels .Summarizing the above-mentioned state-of-art, it can be concluded that in the case of particleboards, several different attempts have been made to change the surface and structure properties, as well as to improve the mechanical and/or physical parameters of the panels by addition of lignocellulosic fibrous materials. However, there is no clear and universal data about the results of that approach. What is more, sometimes the results show an opposite influence of the fibers’ addition to particleboards . There is also a lack of information about the influence of the addition of different types of fibers to particleboard structure on the properties of particleboards modified that way. The fibers’ morphological characteristic (degree of defibration/freeness) is crucial in the case of fiberboards and MDF ,18,19,20To fill this gap, the aim of this study was to evaluate the selected mechanical and physical parameters of single and multi-layered particleboards with the structure modified by the incorporation of wood fibers. In the scope of the research, the influence of type and amount of fibers, way of fibers’ implication (separate layer or mixed with particles), panels’ density, as well as face layers’ share on the panels’ properties has been investigated.Pinus sylvestris L., about 4% of moisture content (MC), intended to face and core layers particleboard production, received from a plant located in Poland, have been used. Two types of fibers have been tested in investigations: fiber type 1 was taken from the medium-density fiberboard (MDF) industry , and fiber type 2  was taken from fibrous insulating materials. Both plants were located in Poland, and both types of fibers were produced mostly from Pinus sylvestris L. The degree of defibration of the fibers, established by producers according to [The industrial particles, pine rding to  on vibra−1 of the nominal thickness of the panel. No calibration (by sanding) has been conducted after pressing the panels. The pictures of the morphology of the surface of the tested composites are shown in The panels of 750 mm × 550 mm, 16 mm nominal thickness, were produced with the resination as follows: 9% for particles and 15% for fibers. The core layer particles and face layers fine particles have been blended in a laboratory glue blender with glue mass separately. In the case of mixed fine particles and fibers for the face layers, these materials have been blended with glue mass, where the resination was tuned accordingly to the mass share of the fibers. The pressing was conducted with a hot press (ZUP-NYSA PH-1P125) at a pressing temperature of 200 °C, press closing time of 10 s, specific maximum unit pressure of 2.5 MPa, and a pressing factor of 10 s mm-−3, fibers type 1; variable factor: mass share of fibers 0%, 25%, 50%, and 75% ;Constant factors: number of layers 1, nominal density 660 kg m-−3, fibers type 1, face layers mass share 16%; variable factor: mass share of fibers in face layers 0%, 25%, 50%, and 75% ;Constant factors: number of layers 3, nominal density 660 kg m-−3, fibers type 1, face layers mass share 32%; variable factor: mass share of fibers in face layers 0%, 25%, 50%, and 75% ;Constant factors: number of layers 3, nominal density 660 kg m-−3 ;Constant factors: number of layers 3, fibers type 1, face layers mass share 32%, the mass share of fibers in face layers 50%; variable factor: nominal density 580, 620, 660, and 710 kg m-−3, face layers mass share 32%, the mass share of fibers in face layers 25%; variable factor: fibers type 1 and 2 ;Constant factors: number of layers 5 .Constant factors: number of layers 3, fibers type 2, face layers mass share 32%, the mass share of fibers in face layers 50%; variable factor: nominal density 580, 620, 660, and 710 kg mThe following constant and variable/changed factors have been investigated :-ConstanThe test specimens were cut accordingly to EN 326-2  and EN 3t-tests calculations were used to test (α = 0.05) for significant differences between factors and levels, where appropriate, using IBM SPSS statistic base . A comparison of the means was performed when the ANOVA indicated a significant difference by employing the Duncan test. The statistically significant differences in achieved results are given in the Results and Discussion paragraph whenever the data were evaluated.Analysis of variance (ANOVA) and −2, statistically significantly different from panels 1, 2, and 4, found for panel 3, can be influenced by the low density of the face layers since these are responsible for carrying the strains during bending. The same explanation applies to panel 2, where the highest MOR (14.5 N mm−2) has been reached. This phenomenon has been confirmed by [−2 to 15.6 N mm−2) has been found (panel type 5–8). In these panels, comparably low content of face layers (16%) contains rising content of fibers, which, retained in outer zones, significantly improve bending properties. This phenomenon is strongly connected to the density of the face layers of panels 5–8, where the increase in density of these zones is well visible. Among this group, there are statistically significant differences between MOR values of panels 5 and 6–8, as well as between panels 6 and 8. When increasing the face layers’ share to 32% (panels 9–12), the rise of the fiber content in face layers causes a rise in MOR values. However, a statistically significant increase can be found when fiber content rises from 0% (panel 9) to 25% (panel 10). The remaining panels’ MOR values remain on a similar level. Such stabilization of MOR values for panels 10–12 is due to the similar density profiles of the face layers of these panels. When investigating the influence of the panel’s density with constant 50% fiber content , it can be concluded that the density increase in the range of 580–710 kg m−3 provides a higher modulus of rupture, in the range of 11.1 N mm−2 to 17.1 N mm−2. The rising average density is clearly displayed on the density profiles of the tested panels. The statistically significant differences in MOR mean values have been found for panels 13 and panels 11 and 15, as well as between panels 14 vs. 11 and 15. The comparison of MOR values of panels of different fibers type in face layers shows no statistically significant differences (panels 16 and 17). A slightly higher MOR of panel 17 (fiber type 2.); however, against the theory of fibers size contribution to panels’ mechanical properties [−2 to 19.5 N mm−2) with the density rise. The effect of higher densification of the fibrous zone of the panels has also been confirmed by [−2, it can be said that it is hard to state whether single-layer panels (1–4) meet the mentioned requirements, due to the high irregularity of MOR values. The standard requirements have not been met by panels 5 (no fibers in face layers of the 3-layer panel), 13, and 18 (the lowest density).The results of the modulus of rupture investigation have been displayed in irmed by . When teoperties . The anat MOR 14. N mm−2 hirmed by  for P2-t−2.The results of the modulus of elasticity investigation are presented in −2 , where the IB of panel 1, without fibers addition was 0.46 N mm−2. There is no clear relation between changed fiber content and IB. However, a slight reduction of the core layers’ density was found, from 592 kg m−3 for panel 1 to 566 kg m−3 for panel 4  of IB with rising fibers share has been found for panels 9–12, where the face layers share was 32%. However, the mentioned IB average values, from 0.41 N mm−2 to 0.46 N mm−2, were slightly lower than in the case of the same fiber content but a lower contribution of face layers (panels 5–8). The core layers density of panels 9–12 rose from 552 to 579 kg m−3 (−2 for panel 13 (of the lowest density) to 0.42 N mm−2 for panel 15 of the highest density. The fiber content was 50% and was on a constant level here. The statistically significant differences in mean IB values have been found for panels 13 vs. 14 and 15. In addition, the density of core layers was raised for mentioned panels (−2) and 17 (0.45 N mm−2), where the different fibers were applied. A high difference in IB was noted when changing the density of panels made with the use of fibers type 2. As shown in −2 for the panel of the lowest density to 0.55 N mm−2 for the panel of the highest density. That IB change was more spectacular than for panels 13–15, where the fibers type 1 were applied. However, the density of the core layers of panels 13–15 and 18–21 were similar , it shoments of . Accordiments of , a stron−2, whereas the SS of panel 17 with fiber type 2 is 1.2 N mm−2. This means over 71% higher value. In addition, the rise of the density of panels 18–21 caused the significant SS rise only between panels 18 and 19 when further density increase did not lead to higher SS.The results of the surface soundness measurement are displayed in The similarity of SS and IB results can be explained by the method of testing (load applying) of the samples. In both tests, the force works perpendicular to the wide surface of the panel, trying to pull the material. As far as in the case of IB, the sample breaks mostly in the middle of thickness, where the lowest density can be found; in the case of SS, the zone around the pulling equipment is cut off partially through the depth of the face layer of the highest density so that the break occurs still in the panel structure, but sometimes not exactly in the highest density zone. Considering that the density of panels was higher in the near-surface zone than in the middle of the thickness, as has been shown on density profiles, the SS values are significantly higher than IB. These findings, also connected to the density distribution over the panel thickness, have been confirmed by the previous research . Accordi−2 required): single layer panels of 50% and 75% fiber content (panels 3 and 4), panel 6, however, there is a high fluctuation of individual results of this mean value (error bars); 5-layer panel 16 of 50% of fiber type 1.Referring the achieved SS results to the requirements of  turns ouIn −3 to 710 kg m−3, and where the fibers’ content was 50% in the face layers, it can be concluded that the density profiles are shifted proportionally to the panels’ density rise, with the higher shift of panel type 15, where the density rise was 50 kg m−3 instead of 40 kg m−3 as it was for panels type 14 and 11. The clear difference between the density profiles of the panels with the content of different fibers type (1 and 2) has been found in The representative density profiles of the tested panel have been presented in The conducted tests showed that single-layer particleboards made of wood fibers and particles do not meet the standard requirements specified in EN 312  for P2-tThe above phenomenon also occurred, but to a much lesser extent, during the blending of the mixture of fine particles and fibers used for the face layers of the three-layer boards.The properties of the three-layer boards are closely related to the density of the boards, as well as to the face layers and fiber share. The influence of the share of layers on static bending and the modulus of elasticity is also clear. It is visible mainly in the case of lower board density, as well as the influence of the type of fibers used. The application of the fibers intended for MDF production allowed the achievement of higher mechanical parameters of the panels due to the higher densification of the face layers. Additionally, better surface roughness characteristics have been found for panels with these fibers. The test results showed that the production of three-layer boards meeting the requirements of the above standard should not pose any difficulties; it is even possible to obtain boards with much higher strength than required or with standard properties, with a density lower than the average for the currently produced furniture boards. That shows the potential of particleboard density reduction by fiber incorporation without losing the crucial features of the panels.The five-layer boards meet the standard requirements to the full extent, but the continuation of research on their use does not seem justified. The strength of the near-surface layer (surface soundness) is lower than that obtained for three-layer panels, and the manufacturing process is more complicated and, thus, less effective.−3 to 710 kg m−3, radically improves all the mechanical features of the panels, with the minimal improvement of surface roughness. The same test, but with the use of fibers of a higher degree of defibration, leads to an improvement of all the tested mechanical properties, as well as surface roughness, even if referred to panels with a lower degree of defibration. When comparing the influence of the type of the fibers used with the remaining constant panels’ production parameters, as 100% fibrous face layers in 5-layer panels, it can be said that there was no significant influence of fibers type on panels’ mechanical parameters, like MOR, MOE, and IB, but the important rise of SS and surface roughness improvement has been noted. The better surface roughness is due to the fact that the fibers of a higher degree of defibration (finer) have been used, as well there was higher densification of face layers found on the density profile. What is important here, the fibers of a lower degree of defibration, which are of higher strength and thus intended for medium-density fiberboard production, did not improve the MOR and MOE properties. It can be concluded that in the case of single-layer panels, the fiber content is an important factor influencing the panels’ performances. In the case of 3-layer panels, there is an optimal 50% ratio of fiber content. It is preferable to use fibers of a higher degree of defibration when producing fibrous-particle panels.The influence of the share of the fibers type 1 (lower degree of defibration) on properties of the single layer panels of constant density. There is a significant improvement in the mechanical properties with a 25% fiber contribution. This is because of the optimal filling of the empty zones between the large-size particles of single-layer panels. However, the surface roughness (Rpm) is the worst for these panels. The further increase of fibers’ content causes improvement of surface roughness. In the case of the 3-layer panels, where the contribution of face layers in the entire panel is 16%, the rising amount of fibers in face layers to 75% causes over 50% rise of MOR. There is also an increase in MOE and SS, as well as an improvement in surface roughness. The improvement of IB was not so spectacular. In the case of the 3-layer panels, where the content of the outer layers was 32%, the addition of fibers to the face layers from 0% to 75% led to improvement of MOR and MOE, as well as surface roughness; however, the best bending and SS parameters have been found for 50% fibers’ addition, and 75% for best surface roughness. Changing the density of the 3-layer panels of constant 50% content of fibers of a lower degree of defibration in face layers, from 580 kg mThe novelty of the conducted research is the attempt to modify the structure of particleboards by adding various amounts of two different types of fibers by mixing them with particles or adding them as separate layers and producing panels of different densities.