Studies of reliability and content validity comprehensibility involved 234 patients with pulmonary tuberculosis. an integrative review was conducted for theoretical foundation. The sensitivity study comprised 30 patients with pulmonary tuberculosis, who had greater knowledge on tuberculosis (12.03) than the control group (9.93). Factor analysis showed that 7 factors explained 67.8% of the variance. Content validity identified a 98.3 % comprehensibility, and the expert trial assessed the sufficiency, clarity, relevance and coherence criteria, showing agreement between judges. the instrument has studies of sensitivity, reliability and content validity that showed it can be applied to patients with pulmonary tuberculosis; nevertheless, cultural and semantic adaptations must be developed for other scenarios. Mycobacterium tuberculosis, or Koch bacillus. The World Health Organization (WHO) stresses, through the Global Tuberculosis Report 2017, that 10.4 million people around the world contracted TB in 2016Tuberculosis (TB) is an infectious disease of global range, caused by the -Knowledge, Attitudes and Practices (KAP) on TB comprise aspects such as what is the disease, the transmission mechanism, risk factors, signs and symptoms, diagnosis, treatment, and prevention. Knowledge is the ideas, information, and beliefs a person has from factors such as socialization, experiences, culture, and information access, being thus a fundamental component of the CAP since it may affect attitudes, as it defines preferences and predisposes to actions. Attitudes are predispositions, values, and emotions people have when facing a situation; and practices are actions performed, which stem from the family context, knowledge, attitudes, habits and customs, among others, that one may have before a health phenomenon such as the TB”End of TB” Strategy Post 2015, proposes in Pillar III - which is related to scientific research and innovation - the importance of research in optimizing the execution and impact of the resources of TB control programs, so that the construction of an instrument on the KAP of patients with PTB seeks to subsequently generate the measurement of educational interventions that strengthen the adherence to anti-tuberculosis treatment and, thus, contribute to the control of tuberculosis through health educationThe Collective Health and Care Research Group of the Nursing School of the National University of Colombia has previously conducted an integrative review aimed at describing the scientific production of tools and instruments for assessing knowledge on TB and that are available for the health personnel, patients, community and family; it was found that there are no reliable and valid instruments to be applied in patients with Pulmonary Tuberculosis (PTB)-In this sense, the adequate knowledge of TB patients about their disease can promote adherence to tuberculosis treatment and, therefore, avoid the appearance of drug-resistant forms of TB; promote the identification of contacts of people with TB; strengthen the early detection of the disease and the demand of health services for new cases; promote assistance to controls with the health team and the performance of bacteriological controls; avoid practices of self-stigmatization, such as isolation in rooms of the dwelling and not sharing food and utensils with the family, and may even transform the inadequate attitudes and practices of TB patients about their diseaseTo analyze the KAP, one needs to develop reliable and valid instruments that allow the systematic observation of health phenomena from the definitions of the construct, its dimensions and itemsThe Standards for Educational Psychological Testing are considered in building such instrument. The development of measuring instruments includes the theoretical foundation, systematic observation of the phenomenon of interest, and empirical studies to measure the sensitivity, reliability and validity of such toolMethodological study that measured the sensitivity, reliability and validity of the content within a measuring instrumentIn phase 1, the theoretical foundation was developed to define the variables associated with the KAP of PTB patients on their illness, to make a structure measuring key aspects of the phenomenon and to direct the development of itemsThe integrative review aimed at describing the theoretical and conceptual development in building an instrument with reliable and valid measures of the KAP of PTB patients. Articles published in indexed journals from January 1, 2010, to August 31, 2016, and which included the KAP of PTB patients on their health/illness process were included. Articles that dealt with the KAP of patients with extrapulmonary TB were excluded. The Descriptors in Health Sciences (DeCS) used were: Knowledge Attitudes and Practices in Health; Tuberculosis; Patients. The Medical Subject Headings (MeSH) used were: Health Knowledge, Attitudes, Practice: Tuberculosis; Patients. Different search equations were performed with the previously described descriptors. Subsequently, articles were critically evaluated by the researchers and the classification of evidence levels proposed by the Scottisch Intercollegiate Guidelines Network (SIGN) were usedConsecutively, the dimensions and items of the instrument were defined, and a version was devised to be applied in a pilot test with 30 PTB patients from a Bogotá health institution, to analyze its comprehensibility. Patient inclusion criteria were: people with PTB who received treatment by the TB Program of Bogotá, people newly admitted into the program, and those aged more than 18 years old, who agreed to participate trough a written informed consent form. The exclusion criteria were: people with cognitive disabilities and people in readmission modality due to abandonment or relapse.In phase 2, a sensitivity analysis was conducted on the knowledge dimension of the instrument, with 30 PTB patients and 30 people forming a control groupResponses of the items were functionally analyzed from the psychometric model proposed by Sperman, which assumes that the number of correct responses is proportional to the attribute evaluated. Difficulty and discrimination parameters were calculated and compared. Difficulty indicated the level of knowledge of the groups regarding the information asked. This item was calculated from the percentage of participants who responded it correctly; an analysis that allowed comparing the number of correct answers in each group, which showed values ranging from 0 to 1 - values close to 1 indicated the item was more difficult for the group of patients with PTB or for the control group. Discrimination is a statistical parameter that is related to the ability of the items to be answered by people who dominate the information and by those who guess randomly without knowing the subject, it was calculated considering low and high performance groups: the values ranged between -1 and 1. Negative values indicated that the group with the lowest score answered the item randomly, and values close to 1 meant that the group answering the item showed a higher score compared to the knowledge about TB and, therefore, the item had greater discriminationIn phase 3, the reliability of the instrument was assessed, which refers to the metric property that is related to the ability of the test of offering an estimate of the attribute magnitude with the least possible error, so that the result is as much closer to the reality of the phenomenon under study as possible, and can show the precision or consistency of the result obtained through the use of the instrument along several measurementsInstrument performance was analyzed through the responses of a sample of PTB patients, to define whether the variance of responses was related to the KAP construct of PTB patients about their illnessWhere K is the margin of error (precision); N, the size of the study population; n is the sample size; so that the following results were found: The sample size was 206 PTB patients newly admitted to the TB Control Program of Bogotá. Inclusion and exclusion criteria of PTB patients were the same already mentioned for the pilot comprehensibility test and for the sensitivity test for the group of PTB patients. Subsequently, the consistency of the responses in each of the components was analyzed through a factorial analysis of the 3 proposed dimensions; Cronbach’s alpha was used to analyze the internal consistency of the items and the reliability index, whose value allows us to estimate the percentage of possible error in the estimation of the attribute magnitudeA study of comprehensibility was developed with the same sample of PTB patients who participated in the reliability test and with experts’ judgement. Comprehensibility was evaluated from the reports of patients about the language, clarity, punctuation and writing, using a qualitative scaleIn phase 4, the evidence of content validity was obtained, so that an expert judgment was developed to conceptually support the measuring instrument. The judgement of experts assessed the criteria of sufficiency, clarity, relevance and coherenceThe statistical analysis of the PTB patients’ responses to the items was performed to identify the average and standard deviation of the KAP levels of the patientsRegarding ethical considerations, the research complied with the provisions of Resolution 8430 of the Ministry of Health and Social Protection of Colombia and was classified as a minimal risk since no physical or psychological modification was made to the participants, as only the instrument was applied to PTB patients and to the control group, after signing a written informed consent formRegarding the integrative review, 1,747 articles were found through the use of search equations with the aforementioned descriptors and Boolean operators. Subsequently, 34 articles whose full text was available were selected, mainly those that included the topic of KAP in PTB patients on their disease and those that were repeated were excluded. According to the SIGN level, 28 (82.3 %) articles were classified into level 3 , 1 (2.9 %) into level 2- , and 5 (14.7 %) into level 2+ Likewise, of the 34 selected articles, 4 (12 %) were published in 2010, 3 (9 %) in 2011, 4 (12 %) in 2012, 2 (6 %) in 2013, 5 (15 %) in 2014, 10 (29 %) in 2015 and 6 (18 %) until August 31, 2016. Regarding the continent and/or region of publication, 11 (32 %) were developed in Asia, 10 (29 %) in Africa, 6 (18 %) in Latin America, 4 (12 %) in Europe, 2 (6 %) in North America and 1 (3 %) in Oceania. Then, a version of the instrument was devised, consisting of 3 dimensions and 43 items. Also, the instrument included a section of general information about the patient with TB, with 21 questions; a section of programmatic data on TB, with 10 questions; a section of programmatic data on TB and HIV, with 9 questions, and a section on TB information sources, with 4 questions. This version was subjected to a comprehensibility analysis with 30 PTB patients, and 7 items  with a comprehensibility lower than 95% were found, which were adjusted according to the observations of patients with TBP, to facilitate their comprehensibility. The average comprehensibility of the knowledge dimension was 95.75 %; of the attitude dimension, 100 %; 96.6 % for the practice dimension, and 97.4 % on instrument comprehensibility. The sensitivity test was carried out with 30 PTB patients and 30 people forming a control group. In the group of patients with PTB, 12 (40 %) were adults (from 40 to 59 years of age), 11 (37 %) young adults (from 20 to 39 years old), and 7 (23 %) older adults (60 years or older); 20 (67 %) were male and 10 (33 %) female; 1 (3 %) did not have any level of education, 12 (40 %) had primary education, 14 (46 %) had high school education, 2 (7 %) had technician/technologist level, and 1 (3 %) had university education. Of the control group, 14 (47 %) were young adults, 13 (43.3 %) adults, 2 (6.6 %) older adults and 1 (3 %) was an 18-year-old teenager; 20 (67 %) were female and 10 (33 %) were male; 19 (63 %) had high school education, 9 (40 %) had primary education, 1 (3%)was a technician/technologist and 1 (3 %) had higher education. It was found that, of the 24 questions related to the dimension of knowledge on PTB, the average in the group of patients was 12.03 and, in the control group, 9.93. In the group of PTB patients, the average difficulty was 0.38, whereas in the control group it was 0.57. Details on the degree of difficulty of the 24 items of the dimension of knowledge on PTB are shown in Likewise, 234 patients with PTB participated in the reliability study, so that the sample size was exceeded by 13.5%: 149 (63.7%) men and 85 (36.3%) women; 17 (7.26 %) were between 18 and 19 years old, 81 (34.6 %) were young adults, 52 (22.2 %) adults and 84 (35.9 %) older adults; 167 (71.3 %) did not belong to any TB risk group, however, 30 (12.8 %) were homeless, 20 (8.6 %) were deprived of liberty, 10 (4.3 %) were health workers and 7 (3%) belonged to the indigenous population; 20 (8.5 %) had no formal education, 79 (33.7 %) completed only the primary level, 101 (43.1 %) went to high school, 19 (8.1 %) were technicians/technologists and 15 (6.5 %) had university education.Factor analysis results showed 7 factors that explained 67.8 % of the total variance, which shows a structure consistent with conceptual approaches that defined the KAP dimensions. Knowledge on PTB is the main factor, which comprises 24 items; however, items 14 and 19 were placed in other factors. The second factor are the PTB practices, consisting of 10 items; items 31 and 37, however, were placed under other factors. Four items were grouped under the dimension of attitudes, but some of them have a low factor load. The same 234 PTB patients who took part in the reliability tests participated in it. One can see that the average comprehensibility of the instrument was 98.3 %; hence, the items were understandable for the population under study. In addition, adjustments were performed in some of the items according to the participants’ reports, as shown in Three judges with expertise in the subject of TB and with professional and postgraduate academic training participated in the expert judgment: two members of the Colombian Anti-Tuberculosis League and one who worked in the TB Control Program of Bogotá. Regarding sufficiency, 37 (97.3 %) of the 38 items were consistent among the judges since they obtained a rating of 4, meaning the items that belong to this same dimension were sufficient to measure it. However, item 14 gave rise to discrepancies and its interquartile range was 1.5 because one of the judges considered such item did not contribute to the measuring of the dimension of knowledge on PTB, insofar as it is part of programmatic aspects facing treatment access, for which it was modified. As to clarity, the 38 (100 %) items were consistent among the judges, obtaining a score of 4, meaning, therefore, the syntax and semantics of the items was appropriate. Concerning relevance, 36 (94.7 %) of the 38 items were consistent among the judges since they obtained a rating of 4, which shows they were essential and should be included so to not affect the measurement of the dimension; nonetheless, in items 14 and 21 the interquartile range was 1.5, as one of the judges considered item 14 was not relevant, reason why it was modified, and other judge considered that item 21 should be included into other dimension, for which it was also modified. After the psychometric analysis for the sample of 234 PTB patients, the scale was defined through direct scoring, using as criterion the appropriate KAP on the patients’ PTB, and the levels were established considering the normative behavior of the sample. Four levels of KAP on PTB were established, namely: High , medium-high (14-18), medium low (9-13) and low , which allowed classifying the KAP of PTB patients for the design and implementation of educational processes in Health. The KAP construct on the illness of PTB patients was developed from a integrative review in 6 databases, which allowed operationalizing the construct, and the items corresponded to the theoretical and conceptual development. To construct the items, we considered the collaborative TB/HIV actions promoted by the WHO. The average instrument comprehensibility was proved to be 97.4 % in the pilot test, and adjustments were made to the 6 items that showed a understandability below 95%. The instrument was shown to be sensitive for the population under study, so much that PTB patients attained an average score of 12.03, whereas the control group reached 9.93. However, in the comprehensibility study of content validity - conducted with 234 PTB patients, one can see an average item understandability of 98.3 %. In addition, some semantic adjustments were performed in the items that were not fully understandable. This shows the instrument is understandable for PTB patients in the city of Bogotá, and may require cultural and semantic adaptations to be replicated in other zones of Colombia and other countries, according to the characteristics of the population under study. -In this methodological study, we identified that items 14, 19, 31 and 37 assessed specific aspects of TB that were not associated with any of the 3 KAP factors and, possibly, evidence new variables that should be reviewed in the future. Item 14 assessed the knowledge on the free access to anti-tuberculosis treatment, which many studies have identified as a programmatic knowledge that fosters the adherence to TB treatment and should be evaluated in the patientsItem 31 identified the practice of TB patients of hiding their diagnosis, as it had been observed they do so in their places of work and study for fear of being rejected, which can reduce adherence to treatmentThe appropriate KAP of TB patients on their illness is a tool that can help reduce the transmission of this disease and wrong practices, decrease the self-medication and stigmatization, promote the adherence to anti-TB treatment, detect early contacts of TB patients who may have the disease and promote the demand for health services in new casesSimilarly, the Collective Health and Care Research Group of the School of Nursing of the National University of Colombia considers it important to develop instruments with reliable and valid measures on TB KAP of other population groups, such as health workers, community and family. The KAP measuring instrument of PTB patients on their disease was constructed from an integrative review that supported the operationalization of the construct and includes empirical studies that support its sensitivity, reliability, and content validity. However, other psychometric studies are needed that analyze in greater depth items 14, 19, 31 and 37, which were not located in the dimensions related to the KAP. Finally, the Collective Health and Care Research Group of the School of Nursing of the National University of Colombia has developed studies on the topic of KAP on TB for more than 10 years and has identified the need to have instruments with sensitive, reliable, and valid measures. Therefore, the KAP instrument in PTB patients with constitutes an advance in the measurement of this phenomenon and will allow the development of other studies, of greater scope, in the city of Bogotá and in other scenarios, aimed at generating educational, political, economic and social interventions that allow transforming the KAP and, thus, contribute to the control of TB.


Data has revealed that the composition and acidic character of the carbon additive are important parameters in the performance of the Bi2WO6/carbon catalysts. The presence of a carbon additive improved the conversion of the dye, evidencing the occurrence of charge transfer reactions that involve radical mediated reactions. The catalysts prepared with 2 and 5 wt.% of carbon additive outperformed the bare semiconductor, despite the shielding effect of the carbon matrix. The acidic nature of the Bi2WO6/carbon catalysts governs the degradation pathway , that proceeds via the deethylation of the auxochrome groups of the dye at short irradiation times, followed by the cleavage of the chromophore at long irradiation times. Regarding the characteristics of the carbons, the photocatalytic degradation rate is accelerated by carbons of acidic character and high oxygen content, whereas the porosity seems to play a minor role. The presence of the carbon additives also affects the toxicity of the treated solutions, rendering lower values after shorter irradiation periods.We have explored the impact of the incorporation of various amounts of carbons from varied physicochemical features as additives to Bi Howevatalysts .2 in sunlight-driven photocatalysis due to their good light absorption properties under visible light [Numerous efforts have been made in the last decades to overcome this, such as semiconductor engineering synthesis  aiming at band-gap tuning and reduction of the surface recombination ,9,10,11.le light ,13,14. Hle light ,16. All 2WO6 can be enhanced by the use of certain amounts of carbon additives; nevertheless, the effect of the carbon additive has been barely addressed, and the optimum nominal carbon content seems to be unclear and dependent on the nature of the carbon additive [On the other hand, the use of carbon either as semiconductor dopant or as additive has been revealed as an interesting alternative to attain high photoconversion efficiencies of various semiconductors, due to its ability to delocalize the charge carriers (thereby reducing surface recombination) in the π-electron density of the graphitic layers ,18. Nanoadditive ,25,26,272WO6/carbon photocatalysts, using carbon materials of various origins and characteristics, covering composition, acidity, and porosity. As the target compound, we have used Rhodamine B, a toxic fluorophore widely used in industrial purposes such as dyeing in textiles, paper, and paints, cosmetic products, and imaging in biotechnology applications [2WO6/carbon catalysts, and demonstrate the correlation between the photocatalytic activity of the hybrid semiconductor/carbon catalyst and the origin and the amount of the carbon additive, specific surface interactions and nanopore confinement.Taking this into account, the objective of this work was to throw some light on the impact of the physicochemical features of carbon additives on the photocatalytic performance of Biications . This re3PO4 (ca. 0.5 g P/g) of a coconut shell at 450 °C; sample CB, obtained upon steam activation (ca. 850 °C) of bituminous coal ; sample CS, obtained by hydrothermal carbonization of 0.5 M glucose at 180 °C (heating rate of 100 °C/h) for 10 h [Several carbon materials with varied physicochemical and structural characteristics were selected in this study: sample CL prepared by chemical activation in Hfor 10 h . Before 2WO6 (BWO) was synthesized by a hydrothermal treatment in the presence of different amounts of the carbon materials ranging from 2–5 wt.% [3) 3·5H2O  were dissolved in 10 mL of glacial acetic acid and 0.005 mol of Na2WO4·2H2O  were dissolved in 90 mL of distilled water. Both solutions were mixed with the adequate amount of carbon additive, sonicated for 15 min and stirred for 30 min to allow a good dispersion of the reactants. The suspensions were then transferred into a Teflon-lined stainless steel autoclave and heated at 140 °C for 20 h. The obtained solids were filtered, repeatedly washed and dried overnight at 120 °C. The control synthesis of the bare semiconductor (sample BWO) in the absence of carbon additives was carried out in the same conditions. The photocatalysts were labeled as BWO/X-Y, X being the acronym of the carbon material and Y the amount (wt.%) incorporated.For the preparation of the photocatalysts, the semiconductor Bi2–5 wt.% . Briefly2 adsorption/desorption isotherms at 77 K in a volumetric analyzer . The samples were previously outgassed under vacuum at 120 °C for 17 h. The gas adsorption isotherms were used to calculate the specific surface area (SBET), total pore volume (VPORES), and micropore volume (W0), the latter using the Dubinin-Radushkevich equation [4 as a blank reference. Measurements were recorded between 220–700 nm (due to the configuration of the integrating sphere) in the diffuse reflectance mode and transformed to a magnitude proportional to the extinction coefficient through the Kubelka-Munk function, F(R∞) for the estimation of the energy band gap. The acidity of the catalysts was characterized by NH3 chemisorption in a volumetric analyzer (Micromeritics). About 400 mg of the catalysts were previously outgassed at 120 °C; an adsorption isotherm of ammonia at 40 °C was recorded from vacuum up to 500 mm Hg. Subsequently, the physisorbed fraction was removed by heating at 40 °C for 4 h, and a second NH3 isotherm was recorded at the same temperature. The amount of chemisorbed ammonia corresponds to the difference in the volume adsorbed from the first and second isotherm, and was used to estimate the total amount of acid sites of the catalysts [4 buffer (pH 3) and the appropriate volume of DMPO to reach 18 mM. Samples were irradiated for 20 min . ESR spectra were recorded from the solution at room temperature on a Bruker ESP 300E X band spectrometer [The porosity of the catalysts and the carbon materials was determined by Nequation . The moratalysts . The hydatalysts  with hydtrometer .2 as determined by a photodiode . The emission spectrum of the lamp is shown in 2SO4:CH3OH of 35:65 v/v, flow rate of 0.8 mL/min, injection volume 50 μL). Aliquots of ca. 2 mL were removed periodically during the experiments and filtered (0.45 mm nylon filter) before measurement; Total Organic Carbon (TOC) was followed also by means of a TOC analyzer (Shimadzu VCPH). The corresponding control experiments (photolysis) in the absence of photocatalysts were also conducted in similar conditions, for comparison purposes. All of the experiments were performed at least in duplicate, with an accuracy of ca. 5% for the photocatalytic runs (average data is presented).Photodegradation experiments were performed at room temperature using simulated solar light  with a photon flux of ca. 120 mW/mVibrio Fisheri test, using a Microtox M500 Analyzer  according to international procedures . The bioluminescent bacteria were provided by Hach Lange France SAS. The luminescence intensity of V. Fischeri bacteria was measured after 5 and 15 min of exposition to the solutions at 15 °C, under 20% NaCl and adjusting the pH to 6–8 when necessary. All of the solutions were previously filtered (0.45 mm nylon filter) to prevent contact of the catalyst powders with the bacteria. Sensitivity of the bacteria was previously tested by using reference compounds (phenol and zinc sulphate). Results were used to determine the luminescence inhibition after 15 min of exposure (%) at dilution rates between 50–5%. All of the tests were performed at least in duplicates for all of the dilutions and exposure times.The toxicity of the solution after the photocatalytic treatment at various sunlight irradiation times was evaluated by the luminescence inhibition of 2WO6) can be improved through the incorporation of a carbon additive in the formulation of the photocatalyst. However, neither the optimum nominal carbon content nor the role of the nature of the carbon additive on such improved performance seem to be well understood [2WO6/carbon catalysts containing low amounts of carbon additive and using carbon materials of varied origin and properties .Various studies, including our own, have reported that the photocatalytic activity of certain semiconductors  ; the BWO2O3 (ca. 420 nm) [The carbon additive induced some changes in the optical response of the BWO/carbon catalysts, as seen in UV-visible diffuse reflectance spectra . The spe 420 nm) ,41 was n6 octahedra and (Bi2O2)2+ units, rather than existing as isolated particles that would otherwise render the stoichiometric textural features of a physical mixture of the components of the catalyst.Concerning porosity, the main textural parameters of the catalysts are compiled in 2WO6/carbon catalysts towards the degradation of RhB under simulated solar light, in terms of RhB conversion. The conversion corresponding to the photolytic degradation in the absence of any catalyst was around 5% after 3 h of irradiation  or the composition of the carbon additive as shown by XPS .The analysis of the solution by UV-Vis spectrophotometry A reveale3, TiO2, silica-titania mixtures) with predominance of the successive deethylation mechanism favored in acidic photocatalysts [The predominance of the degradation route via the successive deethylation of the alkylamine moiety at short times is expected considering the overall acidic nature of the catalysts. In our experimental conditions RhB is a zwitterion with negative (carboxylic) and positive (diethylamino) charges in the auxochrome groups. Since our catalysts are mainly negatively charged , RhB is atalysts ,45 over atalysts .RhB photodegradation may also proceed via a photosensitization mechanism since the dye itself absorbs in the range 460–600 nm as shown in Another possibility is the separation of the photogenerated charge carriers (electrons and holes) through their reaction with water molecules co-confined in the pores of the catalysts, leading to the formation of reactive oxygen species (ROS). The ability of the BWO/carbon catalysts to transfer the photogenerated charge carriers was confirmed by electron spin resonance spectroscopy using a nitrone spin trapping agent . Data ha2WO6/carbon materials with different carbon amounts in their composition, with the irradiation time. Unlike TOC measurements, the toxicity test is sensitive to the response of all the compounds present in the solution , thus providing a quantification of the toxicity of the solution after the photocatalytic treatment. Since the luminescence of V. Fischeri is proportional to the metabolic activity of the bacterial population, the inhibition corresponds to lethal or sub-lethal response when it is exposed to a chemical agent; hence, a decrease in the luminescence signal indicates a higher toxicity of the solution and vice versa. This is important since the presence of heteroatoms  can interfere the determination of TOC measurements; this is the case in the degradation of RhB, which presents nitrogen and chlorine atoms in its formula.We studied the evolution of the toxicity of the solutions of RhB treated by the photocatalytic process using BiV. Fischeri bacteria to the solutions before and during the photocatalytic treatment. The toxicity of the initial RhB solution was also evaluated, rendering an inhibition of 77–81% that corresponds to a high toxicity of the initial solution. Indeed, the median effective concentration parameter (EC50) of Rhodamine B was ca. 2.5 ppm  compared with BWO/carbon photocatalysts . Indeed, it was necessary to increase the irradiation time to 3 and 4 h for BWO to obtain the full conversion of the dye  and a luFor the least performing catalysts , we recorded the evolution of the toxicity with the irradiation time. In the case of sample BWO/CB-2, the curve showed a sharp decrease in the luminescence inhibition in the first 30–60 min of irradiation time, in agreement with the fast kinetics observed for the photocatalytic reaction. When the amount of carbon was raised to 5 wt.% (sample BWO/CB-5), the luminescence inhibition reduction is still significant but follows a smoother trend with the irradiation time. For BWO/CL-2, the evolution of toxicity with the irradiation time is also slow in the first 60 min, and is somehow accelerated afterwards. We attribute this to the accumulation of degradation intermediates (short-chain carboxylic acids and N-deethylated compounds) at short irradiation times, that are further degraded at longer times. This correlates with the abundance of intermediates detected in solution by HPLC . The abs2WO6/carbon catalysts prepared with increasing amounts of carbon additives towards the degradation of Rhodamine B has revealed the outstanding role of the physicochemical features of the carbon additive on the catalytic performance of the catalysts, and on the degradation pathway. Despite the strong shielding effect of carbon materials , Bi2WO6/carbon catalysis incorporating up to 5 wt.% of carbon material displayed a faster photodegradation rate than the bare semiconductor under simulated solar light. This effect was independent of the physicochemical properties of the carbon additive, although it was more pronounced for the catalysts incorporating carbons of acidic character with high oxygen content. The accelerated photodegradation evidenced that the presence of a carbon phase in the Bi2WO6/carbon catalysts favors the separation of the photogenerated charge carriers, leading to charge transfer reactions (direct or indirect). These may involve direct hole oxidation, due to the proximity of RhB adsorbed in the catalyst surface, and radical mediated mechanisms formed upon BWO/carbon-photon and carbon-photon interactions . Our data has shown that the photocatalytic performance is dominated by surface interactions between the pollutant and the catalysts, with a low impact of the porosity. The overall acidity of the Bi2WO6/carbon catalysts controls the degradation pathway that proceeds via coupled mechanisms. Although they can take place simultaneously, our data suggest rather a subsequent mechanism with the deethylation mechanism dominates at short times , over the cleavage of the chromophore at long irradiation times, causing the decolorization of the solution. The degradation mechanism follows a similar pattern for the BWO/carbon composites, indicating that the effect of the carbon additive is linked to the kinetics of the photooxidation reaction rather than to a mechanistic change. Based on the conversion and high mineralization values, the presence of the carbon additive accelerates the conversion rate of the dye and its degradation intermediates, rendering a low toxicity after shorter irradiation periods. Furthermore, as the production costs of carbon materials are very low, the impact in the cost of the photocatalysts can be significantly reduced, favoring an eventual upscale of the photocatalytic process. Further studies on the optimization of the carbon additive and stability studies of the catalysts after long irradiation periods are still needed.The photocatalytic performance of Bi


To record the dentition, jaw and facial growth and development of children with class II malocclusion at the age of 7-8 years old in the early dental transitional stage with 3D technology and to provide the study basis for the growth and development parameters of normal children and children with class II malocclusion.Twenty-four children who were suffering class-II malocclusion in the early dental transitional stage and received treatment between July 2016 and July 2017 in our hospital were selected as the study group, and 20 healthy children were selected as the control group in the same period. SIRONA CEREC dentition scanning, 3D reconstruction of the lower mandible and 3d MD face scanning were performed on the children. Relevant data were recorded and compared.The dentition scanning results suggested that the study group had significantly larger anterior overbite and anterior overjet and smaller width of the upper arch than the control group; there was a significant difference between the two groups (P<0.05). The 3D reconstruction of the lower mandible suggested that the study group had smaller Go angle and SNB angle and shorter ANS-Me distance, Go-Me distance and N-Me distance compared to the control group; the differences had statistical significance (P<0.05). The face scanning results demonstrated that the nasolabial angle and facial convexity angle of the study group were significantly larger than those in the control group, and the difference was statistically significant (P<0.05).The dentition scanning results suggested that the study group had significantly larger anterior overbite and anterior overjet and smaller width of the upper arch than the control group; there was a significant difference between the two groups (P<0.05). The 3D reconstruction of the lower mandible suggested that the study group had smaller Go angle and SNB angle and shorter ANS-Me distance, Go-Me distance and N-Me distance compared to the control group; the differences had statistical significance (P<0.05). The face scanning results demonstrated that the nasolabial angle and facial convexity angle of the study group were significantly larger than those in the control group, and the difference was statistically significant (P<0.05). Malocclusion is one of the three major oral epidemic diseases announced by the World Health Organization (WHO). Class II malocclusion which has an incidence of 5%~8% is a common malocclusion in clinics.In the growth and development stage of children, dentition, jaw and facial shape develops rapidly, and malocclusion is easy to occur in that stage.Twenty-four children with class II malocclusion in the dental transitional stage who received treatment between July 2016 and July 2017 were selected as the study group. The inclusive criteria included erupted central incisor in the upper and lower jaws and erupted first molar in the bilateral upper and lower jaws, complete detition, abnormal upper and lower anterior teeth inclination, grade II~III anterior overjet, distal occlusion of bilateral first molar, lateral face protrusion or mandibular retrusion and uncoordinated facial height to width ratio. Familial inherited bone deformity, rampant caries, class III malocclusion, congenital or acquired teeth number and shape abnormality and growth and development diseases were excluded. Moreover twenty healthy children who aged seven or eight years were selected as the control group. They had complete dentition, normal upper and lower anterior teeth inclination, grade I anterior overjet, Grade I~II anterior overbite, neutroclusion of bilateral first molar, coordinated lateral face and coordinated facial height to width ratio. The study group included 15 boys and 9 girls, and they aged from 7~8 years (average (7.8±2.1) years). The control group included 13 boys and 7 girls, and they aged from 7~8 years (average (7.5±2.3) years). No significant difference was found in the general data between the two groups (P>0.05). The experimental program has been approved by the medical ethics committee of our hospital, and the guardians of all the children have fully understood the content of the program and agreed to join the experiment.Non-invasive dentition 3D scanning, 3D reconstruction of the lower mandible and 3D face scanning were carried out on children in the two groups, and the detection data were recorded. The width of the upper dental arch  and the anterior overbite and overjet quantity were measured using SIRONA CEREC orthodontics analysis software. The morphological parameter of mandibular angle was measured using Sim Plant Pro11.04. The variation tendency of nasolabial angle and facial convexity angle were recorded using 3d MD face scanner. The dentition, the morphological parameters of the mandible and facial soft tissue parameters were compared and analyzed.All the data were analyzed using SPSS 20.0. Categorical data were expressed as percentage (%). Measurement data were expressed by mean ± standard deviation. Mean difference was analyzed using independent sample t test. Difference was considered as statistically significant if P<0.05.The scores of the anterior overbite and overjet of the study group were significantly higher than those of the control group, and the differences were statistically significant (P<0.05). The upper dental width  was significantly larger than that of the study group; the differences were statistically significant. It indicated that children with malocclusion had crowded dentition and abnormal tooth morphology. In addition, malocclusion cannot only change oral parameters, but also change the development of the jaw, especially the mandibular morphology and facial parameters.21The results of 3d MD face scanning showed that the nasolabial angle and facial convexity angle of the control group were smaller than those of the study group, and the differences were statistically significant. Compared with normal children, children with class II malocclusion had insufficient development in the lower 1/3 of the face, underdeveloped length of the mandible, underdeveloped alveolar point of the mandible, flatter mandibular angle, and more prominent mandibular chin, and all the differences were statistically significant, which was similar to the research results of El Hajj et al.This study is single-center and small-sample, therefore it might ignore the influence brought by the difference of people from different regions. Hence the future study needs more multi-center and large-sample controlled trial to provide more reliable guidance basis for clinics.This work provides data support for the 3D diagnosis of malocclusion of children in the dental transitional period through detecting the dentition, jawbone and facial morphology parameters using 3D technology. The advantage of this study is that the 3D model measurement effectively reduced fixed point and measurement error, increasing the accuracy of the results, and moreover it proved that the monitoring and treatment of malocclusion should be paid attention to in the dental transitional period.


The article illustrates the impact of basalt filler in the form of flakes and fibres on the toxicity of gaseous products that formed during the thermal decomposition of silicone rubber composites. The values of specific emissions of gases were determined with the help of the IR spectroscopy and further applied to calculate the toxicometric index. The presented method of measuring the concentrations of gaseous products resulting from thermal decomposition consists in the application of a fluidised bed reactor, which makes it possible to conduct the decomposition of a sample at a precisely assumed temperature value and imitate the conditions of a real fire. At a temperature lower than 700 °C, the gases resulting from the thermal decomposition of composites are particularly toxic due to the presence of significant concentrations of formaldehyde that does not undergo oxidation to more stable inorganic products. At a temperature of 600 °C the toxicity of gases for the samples with ceramizable additives and without them was similar. In the first case, there appeared to be a positive synergistic effect of mineral and basalt additives, and the basalt additives themselves increased the toxicity of gases. At higher temperatures of decomposition, the exponentially increasing rate of the oxidation reaction in the gaseous phase results in the lack of significant differences between the toxicity of gases for the samples with and without basalt additives. The toxicometric index value at temperatures of 700 °C and 800 °C was by one or two orders of magnitude higher, respectively, than the one that was observed in the temperature range of 500–600 °C, as inorganic components appear in the place of formaldehyde. Polymers and their composites are commonly used in almost all spheres of life. The manufacture and global consumption of polymers and materials produced from them has been steadily increasing in spite of numerous ecological restrictions mainly related to the limitation of producing considerable amounts of production and post-consumer wastes, which are frequently difficult to manage. The problem of reducing their flammability or flame retardancy is becoming particularly important due to a serious health and life threatening aspect, as well as the pollution of natural environment that is caused by the emission of smoke and toxic gaseous products of their thermal decomposition and combustion. Having analysed the literature on the subject, one might draw a conclusion that 55–80% of all fatal accidents during fires are caused by poisoning with products of thermal decomposition and combustion as well as smoke ,2,3. ToxDuring the thermal decomposition and combustion of polymer materials, the following toxic compounds are most frequently formed: carbon monoxide, hydrogen chloride, hydrogen cyanide, nitrogen and sulphur oxides, nitro compounds, and organochlorine derivatives, including polychlorinated dibenzo-p-dioxins and dibenzofurans ,5. The eThe basis for the activities aimed at reducing the poisoning hazard are the laboratory research results, including the measurements of the following: the potential rate of the formation of thermal decomposition and combustion products, the amount and rate of smoke emission under fixed combustion conditions, the emitted amount of heat, an increase in oxygen deficiency, and the mutual relationships of these magnitudes. When analysing the polymer materials under the same kinetic and thermal conditions, one might estimate their behaviour in fire conditions. Such tests also make it possible to make attempts to modify the composition of these materials in order to e.g. improve fire retardancy or reduce the emissions of toxic products during combustion.Currently, the assessment of the toxic potential of a gas mixture resulting from a fire is based on the Fractional Effective Dose (FED). The necessary condition for the most reliable determination of the FED value is a precise qualitative and quantitative analysis of toxic products that are generated during a fire ,10. The The article presents research results referring to the impact of basalt filler in the form of both flakes (BFL) and fibres (BFS) on the toxicity of gaseous products of the thermal decomposition of silicone rubber composites, including the composites containing ceramizable additives. Basalt fibres were proven to be an environmentally friendly and promising additive to polymer, metallic, and concrete composites , however−1). The rubber was cross-linked with the use of dicumyl peroxide from Sigma Aldrich  in a quantity of 2.5 parts by wt./100 parts by wt. of the rubber. The polymer matrix was methyl vinyl silicone rubber (SR), which was made by Silikony Polskie , with a vinyl group content of 0.05–0.09% ); melamine cyanurate (MC) ; and, calcium carbonate anhydrous, free-flowing, reagent ≥99% . The ceramization-promoting glass frit “A 2120” of the chemical composition (wt.%) 7.3CaO-25Na2O-2.1K2O-4.2Al2O3-61.4SiO2 and softening point temperature of 540 °C was obtained from Reimbold & Strick GmbH, Cologne, Germany; zinc borate ZnO ≥ 45%, B2O ≥ 36% was obtained from Sigma-Aldrich ; basalt flakes (BLF) and basalt fibres (BFS) ).The following compounds were used as fillers in the rubber blends: Aerosil 200 fumed silica (BET specific surface area 175–225 mThe composite mixes  were preThe carbon content in the tested composites (%C) is the weighted average of the carbon content in the individual components of the composite. The balance of this element was also estimated based on the theoretical carbon content in the tested samples, giving the ratio of the mass of carbon atoms in the flue gas, in relation to the initial material subjected to combustion.3/min. while using a TSI 40241 flow meter. The gas composition analysis was carried out at four temperatures: 500 °C, 600 °C, 700 °C, and 800 °C, corresponding to the decomposition temperature of the tested composites. A resistance heating mantle that was connected to the autotransformer was used in order to heat the bed and stabilize the temperature. The Ni-NiCr thermocouple placed inside the reactor, 50 mm from the distributor, was used to measure the temperature of the bed. The masses of silicone rubber samples and its composites have been experimentally selected so as not to exceed the absorbance value equal to 1 in the range characteristic of the silicone rubber matrix (800–1300 cm−1). A composite sample in the form of solid pieces of appropriate mass (from 0.030–0.054 g) was placed at the top of the reactor and it was dropped to the bed where, due to the densities difference, the sample was immersed and eventually landed at the bottom of the reactor. At a given temperature of the bed, the samples were dosed in sequence at regular intervals (lasting from 2 to 20 min.), while three samples were tested for each type of composite. The concentrations of gases during thermal decomposition were continuously analysed and, after the concentrations of the main components , reached the background level, the next sample was placed in the reactor. The presented results are the arithmetic means obtained from three samples of a given type of composite.The gaseous products that were generated during the thermal decomposition of silicone rubber composites have been analysed in terms of quantity and quality. A laboratory set  using fl2O, CO2, CO, NO, NO2, N2O, NH3, CH4, C2H6, C3H8, C2H4, C6H14, HCHO, CH3CHO, HCN, and cyclic siloxanes: D3 (hexamethylcyclotrisiloxane), D4 (octamethylcyclotetrasiloxane), and D5 (decamethylcyclopentasiloxane). In addition, the Horiba PG250 analyser was used to verify the measurements while using other detectors: for measurement of the CO, CO2, and SO2 concentrations the NDIR detectors were used, the NO and NO2 concentrations were measured as the sum of NOx by the chemiluminescence method, and the O2 volume fraction was measured by the electrochemical detector.Quantitative and qualitative data were obtained while using the Gasmet DX-4000 analyser. The device that is equipped with the Michelson interferometer and a gas cuvette with an optical path length of 5 m allows for obtaining the e-m spectrum of exhaust gases while using infrared spectroscopy with Fourier transform (FTIR). The FTIR spectra of gases were continually collected every 5 s during the experiment. Using the library of reference spectra, the computer program deconvoluted the obtained spectra and, in this way, the concentrations of the following organic and inorganic compounds were determined: H2 (2250–2400 cm−1), H2O , and low molecular organic compounds, primarily aldehydes and aliphatic hydrocarbons  (−1 in the form of four bands corresponding to the presence of cyclic siloxanes. The FTIR gas spectra of ceramizable composite reference sample (SR-4) thermal decomposition products (−1 at a temperatures over 600 °C. This is due to melamine cyanurate (MC) introduction (in an amount of 30 phr) to ceramizable composites. MC gradually decomposes, first producing ammonia, which is then oxidised to nitrogen oxides, of which N2O  is particularly characteristic. The other difference between the SR-1 and SR-4 spectra can be lowering the absorbance in the range of typical cyclic siloxanes when significant amounts of fillers are introduced into the polymer matrix in the case of ceramizable composites. The introduction of basalt flakes or basalt fibres to the composites did not substantially alter the spectra, thus these spectra were not shown. Nevertheless, the computer software performed deconvolution of each spectrum obtained during the experiments and enabled one to qualitatively compare the influence of these fillers on the emission and the toxicity of silicone rubber composites.The FTIR spectra of the gaseous product emitted during the reference cross-linked silicone rubber (SR-1) decomposition in the fluidised bed showed the presence of signals originating from CO00 cm−1) a. It is products b do not The experiment was carried out in a continuous way at a predetermined temperature of the bed by successively dosing at given time intervals three samples of each type of the silicone rubber composite. As it can be observed in the graphs illustrating the concentrations of gaseous components in time , the con2 and H2O. These are the final products of the oxidation of organic compounds contained in the polymer material, and, in spite of certain toxicity of carbon dioxide, their significant participation in the combustion products is beneficial from the environmental point of view. The contents of the remaining components, the majority of which exert a negative influence on living organisms and the environment, are much more important. In order to more easily illustrate the concentrations of these components, they were summed up in appropriate groups of compounds in The reading of the FTIR spectrum took place every 5 s, and, on its basis the concentrations of 18 gaseous components , were dAt a temperature of 500 °C a, the thIt should be noted that the samples of the ceramizable composite, both the reference material (SR-4) and composites with an addition of basalt , emitted a similar amount of gaseous components . The introduction of the basalt filler resulted in an increased time of the thermal decomposition process and, consequently, decreased the instantaneous concentrations of, i.a. aldehydes. In this case, there was no differentiation between basalt flakes and fibres, since they only constituted a small part of additives. On the contrary to the basalt fibres in the sample SR-3, the basalt additives were successfully built into the polymer structure in SR-5 and SR-6, which was confirmed in the previous work.2 by basalt fillers.An increase in the temperature of the thermal decomposition process to 600 °C b resulte2 during the combustion of ceramizable composite samples occurred. Probably, at a temperature of 700 °C, the emission of CO in ceramizable composites also increased. However, the total emission of CO was lower than in the case of the composites without ceramizable additives, and the effect was unnoticeable, since the participation of the polymer matrix was smaller in these samples (a large number of additives).At a temperature of 700 °C c, the maThe emission of nitrogen compounds, i.e. nitrogen oxides, ammonia, and hydrogen cyanide, is extremely important from the point of view of the environmental impact. In accordance with the expectations, the presence of these compounds was only detected in the case of ceramizable composites, since they contained a nitrogen source in the form of melamine cyanurate (MC). The obtained positive values of instantaneous concentrations of nitrogen compounds in 2O (the maximum instantaneous concentration approx. 17 ppmv). At a temperature of 700 °C (2O (maximum approx. 80 ppmv), which, also at a higher temperature, 800 °C  are sufficient for allowing the process of ceramization in the bed. The formed ceramic layer effectively reduces the diffusion of oxygen to the reaction zone, whereas its isolating character limits the processes of thermal decomposition. Such an effect might also be due to the presence of the MC, whose degradation proceeds gradually and the time that is necessary for complete oxidation of this compound turned out to be too long in relation to the residence time of gases in the fluidised bed reactor.It is interesting to notice that, during the combustion of the ceramizable composites samples at a temperature of 800 °C, there is no effective oxidation of CO to COThe masses of the obtained components were calculated on the basis of the obtained graphs illustrating the concentrations of gaseous components during the process of thermal decomposition of silicone rubber composites. In this way, an amount of the formed gaseous components expressed as the sample mass was determined , the comThe addition of the basalt filler to the samples of composites not containing ceramizable additives resulted in a decreased emission of gases at all of the analysed temperatures . No cleaHaving converted the data, it turned out that the sample containing basalt fibres, whose decomposition took place very dynamically at 500 °C (SR-3) emitted gases of a similar composition in comparison to the reference material . The onl2 in exchange for CO in flue gases originating from the decomposition of SR-3. At higher temperatures, the kinetics of the degradation and oxidation processes resulted in the absence of significant differences between the samples without ceramizable additives.The same dependencies took place at a temperature of 600 °C, although apparently the addition of both basalt fillers contributed in the same way to slowing down the process of thermal decomposition of gaseous components . The addition of basalt flakes (SR-2) acted as a reducing diffusion factor, due to which the decomposition and oxidation process was stopped. However, basalt fibres probably, similarly like at a lower temperature, caused the violent decomposition of the sample. In consequence, the resulting gases did not manage to undergo further degradation and oxidation, which is proven by a lower participation of CO2 and low participation of CO, aldehydes, and cyclic siloxanes at the same time. On the other hand, at higher temperatures in the samples containing basalt fillers, the oxidation of CO to CO2 was limited. Both of these phenomena  contributed to an improvement in the oxidation process. This was demonstrated by the high participation of CO2) was observed.The carbon balance was calculated by dividing the mass of carbon atoms in the gaseous components formed in the process of thermal decomposition by %C in the composite sample on the basis of a theoretical mass of carbon in the samples %C in  Table 4Table 4. 3) of toxic gases emitted from the combustion of 1 mg of the sample (Equation (2)). Hence, the higher the value of the index, the higher toxic a given material is. The normalized concentration values that were customarily assumed while calculating the values of the toxicometric index are the LCs  values [The mean toxicometric index was used in order to evaluate the toxicity of the gases resulting from the process of thermal decomposition of rubber silicone composites. This is the sum of the toxicometric indices of particular gaseous components (Equation (1)). The toxicometric index is defined as the normalized volume (in m) values ,17,18,29) values .meanW in this case can be calculated according to the equations:n is a number of toxic gases.E is a specific emission of a given compound, derived from FTIR analysis, g/g.Therefore, toxicometric index The proposed method enables including all emitted gases in toxicity evaluation without the need of additional unnecessary animal testing. Although it does not provide a direct value stating whether a given material is toxic, it can be easily adopted to compare toxic hazard in the case of fire for different materials emitting multicomponent gas mixtures.2, which is a product of the oxidation of nitrogen compounds resulting from the MC decomposition  intensifies the process of its physical fragmentation. The sample is divided into smaller fragments at the interface between basalt and the remaining part of the material, which considerably increases the surface of mass and heat exchange in the process. Consequently, the process of the thermal decomposition and emission of gaseous components is accelerated. As a result, at both 500 °C and at 600 °C, the accelerated decomposition of the sample limited the possibility of effective oxidation of the resulting gases. On the other hand, the addition of basalt flakes to the silicone rubber (sample SR-2) creates a thermal barrier and limits the access of air to the sample, thus inhibiting the process of the thermal decomposition of the material. At a temperature lower than 700 °C, the gases formed as a result of the thermal decomposition of composites are particularly toxic, owing to the presence of significant concentrations (up to 150 ppmv) of formaldehyde. It does not undergo oxidation to more stable inorganic products, due to the insufficient availability of radicals in the gaseous phase, which are necessary for its oxidation. At a temperature of 600 °C, the toxicity of gases was similar for the samples with ceramizable additives (2O, CO2, CO, and NOx, appear in place of formaldehyde.At higher temperatures of polymer decomposition, the exponentially growing rate of the oxidation reaction in the gaseous phase leads to the lack of significant differences between the toxicity of gases for the samples with and without basalt additives. The value of the toxicometric index at a temperature of 700 °C and 800 °C was one or two orders of magnitude lower than the one that was observed within the temperature range of 500–600 °C. This indicates an emission of considerably less toxic gases, since inorganic components, such as H


This paper proposes a new method for determining the correction factor of a newly developed waveguide primary power measurement system , based on the electromagnetic field theory analysis for waveguide thermal isolation section (TIS) in foil short measurement mode. The new method determines the contribution of the power dissipated within the TIS into the correction factor, in term of the physical dimensions of the TIS. Performance comparison and analysis show that the newly proposed method can significantly reduce the measurement uncertainty when evaluating the correction factor of waveguide microcalorimeters. Microcalorimeters have been recognized to be an effective solution for radio frequency (RF), microwave, and millimeter-wave power measurements ,2,3, andent ways ,10,11,12In the millimeter-wave range, waveguide microcalorimeter has been adopted due to its good reliability and accuracy up to 110 GHz ,10,11,12However, as the frequency of interest further increases, the size of waveguide becomes smaller which motivates us to find other solutions without using extra fixtures/accessories. As a continued work of , theoretIn the remainder of this paper, the theoretical background and operation principle of a waveguide microcalorimeter is discussed in V1 and V2) at a steady status as follows,The effective efficiency R is the operating resistance of the thermistor mount. V1 and V2 are measured by the Type-IV meter directly.Here, e1 and e2 are the output voltages of the thermopile corresponding to V1 and V2 and measured by a nanovoltmeter. It is noted that this unsubstituted power V2 of the nanovoltmeter.According to the law of conservation of energy, the unsubstituted portion 2] ,12 with For a thermistor mount with input reflection coefficient of Therefore, it can be obtained from Equations (5)–(7) thatAs “Foil Short” measurement has been well-accepted for experimental determination of the correction factor g ,11. A scWith the RF input on, the power For the foil short with a reflection coefficient of Combining Equations (9) and (10), it can be obtained thatSince This relationship has been reported in ,11,12. HThrough reorganizing (11), we can achieve thatWith (9), it is found thatIn this study, a power ratio Combining (15) with (8), a new correction factor g is proposed in this study for evaluating the waveguide microcalorimeter as follows,Note that the significant uncertainty portion involving eters in ). This ieters in . As a reTherefore, proper determination of the power ratio The properties of waveguides in support of wave propagation and mode are characterized by the presence of longitudinal magnetic or electric field components, and can be derived by electromagnetic field theory analysis  as shown in z = 0) isHere, For convenient in calculation, Equation (17) can be reformatted as (19){Hz=Note that the dissipated power Therefore, for the broad wall , the power Similarly, the power Therefore,Here, it needs to be highlighted that final expression in (29) is achieved with the elimination of the surface resistance In practice, these requirements could be achieved during the fabrication of TIS and foil short using the same metal material with enough thickness and with same surface treatment. Together with Equation (16), the correction factor g can be determined properly using (29). In the next section, its performance will be compared with conventional method with detailed discussion.Performance of the newly proposed correction factor g in (16) has been evaluated with a WR-15 microcalorimeter that is now serving as the national waveguide primary power standard of China. The TIS of the fabricated microcalorimeter has dimensions of ρ and the estimated correction factor g covering the whole frequency band (50–75 GHz) for the fabricated WR-15 microcalorimeter shown in g of a reference standard (Hughes 45774H-1100 thermistor power sensor), using the proposed method (Equation (16)) at 72 GHz. sitivity .To obtain the measurement uncertainty The uncertainty for the uncorrected effective efficiency To further evaluate the performance of the proposed method (Equation (16)) with the newly fabricated WR-15 microcalorimeter shown in Comparison results of the measured effective efficiency for one of the traveling standards, Hughes 45774H-1100 thermistor power sensors are presented in In this paper, a new method for determining the correction factor g of a waveguide microcalorimeter was reported, using the electromagnetic field theory to analysis the effect of waveguide TIS in “foil short” measurement mode. The proposed method determines the contribution of the power dissipated within the TIS into the correction factor g, in term of the physical dimensions of the TIS.The proposed method has been implemented to evaluate a newly fabricated WR-15 microcalorimeter at the NIM, China. The estimated correction factor g of the microcalorimeter using the proposed method has been compared against the conventional method, and good agreements have been observed. To further evaluate its performance, the proposed method with the newly fabricated WR-15 microcalorimeter has been evaluated in an informal international comparison of WR-15 (50 to 75 GHz) power measurements with the NIST of USA, the PTB of Germany and the NMC of Singapore, where good equivalence has been observed.


A new type of flexible sensor, which could maintain the deformation consistency and achieve the real-time detection of the variation in load of the measured object, was proposed in this work. According to the principle of forced assembly, PDMS was used as the substrate of sensitive components and electrodes, while carbon fiber was added as a conductive medium to prepare a polymer-based flexible sensor, which effectively overcame the deformation limitation and output instability of conventional flexible sensors due to different substrates of sensitive components and the electrode. Combined with the sensor structure and the forced assembly method, a theoretical analysis of its conductive measurement mechanism was carried out. Meanwhile, an experimental test device was designed to test and analyze the output characteristics of the flexible sensor under a static and dynamic alternating load. The results show that the flexible sensor exhibited linear output under the dynamic alternating load of 10 kN to 60 kN and frequency of 3 Hz. Peak and valley value had the same phase with the load extremes. The dynamic and static experiments show that the resistance output signal and the sensitivity was in the range of 310~624.15 Ω and 171–183 N/Ω respectively. However, due to the hysteresis of the elastic recovery of the polymer, the output repeatability of the flexible sensor under the dynamic alternating load was 5.03% and 0.78% lower than that of the static load, respectively. Combined with the static and dynamic experiments, it was verified that the polymer-based flexible sensor can maintain the same deformation characteristics with the measured object, and at the same time outputted a resistance signal with a certain mapping relationship with the applied load. The repeatability of the output signal under dynamic and static experiments was within ±7%, which can meet the measurement requirements of the fatigue life of the measured body during periodic load. With the development of information technology, electronic technology and polymer synthesis processing technology, as a new type of sensor, the polymer-based flexible sensors have been widely used in the detection of human motion states , physiolPolydimethylsiloxane (PDMS), Poly (PET), polyimide (PI) and parylene, which has superior flexibility, malleability, were often used as the substrate for the flexible sensor. The electrodes were usually made of carbon nanotubes (CNTs), graphene (GN), carbon fiber (CF) and nano-metal materials as the main conductive medium, prepared by different molding methods ,9,10. JSIn this paper, PDMS was used as the substrate of the polymer-based flexible sensor, and the sensing elements and electrodes were assembled with carbon fiber as the conductive medium by a spatial confining forced network assembly method ,15,16. TIn the preparation process, after adding the relevant conductive medium  in proportion in A glue, we then sent the A glue to the internal mixer for thorough mixing. After evenly mixing with the B glue, the whole material was sent to a vacuum drying oven for a vacuuming operation. Finally, the material was evenly placed on the surface of the mold with a triangular microstructure. After the secondary compression molding process which included pressure holding and imprinting stages was carried out in a hot coining machine by a space-limited forced assembly method, a lower flexible sensing film having a microgroove structure was formed. The upper sensing film without the micro-groove structure and the electrode were prepared using the microstructure-free mold under the same process conditions ,18,19,20As shown in Before the static and dynamic experiments, the conductive properties of the sensing film were analyzed by controlling the thickness of the film and the microstructure array. The purpose is to obtain a conductive material with good comprehensive performance, which plays an important role in the preparation of flexible pressure sensors.In the experimental aspect, the conductive properties of the sensing film with a thickness of 1 mm to 4 mm and the triangular and columnar arrays of the same height were analyzed. The film used for the measurement was cut into a circular shape with a diameter of 10 mm.First, the effects of different thicknesses on the performance of the sensing film were analyzed. Through The height of the three microstructures in In view of the above, the size of the sensor-sensing film herein was finally determined, as shown in R is the resistance of the conductor or the semiconductor, ρ is the resistivity of the conductor or the semiconductor; l is the length of the conductor, mm; S is the cross-sectional area of the conductor, mm2; ΔR is the change of the resistance under the external force, Δl, ΔS are the changes of the length and area of the conductive grid under the action of external force, and Δρ is the change of the conductivity of the semiconductor under the action of external force. The rate of change of the resistance of the diffused silicon pressure sensor and the strain gauge is caused by the first term and the second term of the Equation (1) respectively.The resistance output signal of the conventional grid-shaped strain gauge and the diffused silicon piezo-resistive pressure sensor would change under shape deformations caused by tensile deformation and vertical pressure. Resistance variation of these sensitive components was shown in Equation (1) .(1)ΔRR=During the polymer-based flexible sensor packaging process, a certain preload was applied to the conductive films by the upper and lower polymer insulating layers, so that the upper and lower conductive films of the sensor contacted each other to generate a conductive path in the initial state. The measurement mechanism was shown in The resistance change process of the sensor in In the initial state, resistance The polymer-based flexible sensor signal acquisition and processing flow chart was shown in The polymer-based flexible sensor was fixed on the side of the measured elastic element. with the external load, the sensor and the measured elastic component had a uniform deformation under the dynamic alternating load, and the output resistance signal had a mapping relationship. The resistance signal was converted to a standard voltage or current signal (0 to 10 V or 4 mA to 20 mA) by a resistor-voltage/current (RV/I) transmitter, and then converted to a digital value by a standard data acquisition card (A/D conversion). Finally, after being processed by the host computer software, the real-time curve of the pressure F of the sensor and the resistance R of the sensor with time T was obtained.The measured component—dumbbell-shaped rubber high-elastic spring, was shown in First of all, the force deformation performance analysis of the polymer-based flexible sensor and the measured spring is performed. As shown in Under the initial preload of the rubber band, the flexible sensor was in the maximum load state, and the resistance was at its minimum. When the load was applied, due to the continuous outer drum of the side of the spring, the generated surface internal stress along the axial center canceled a part of the initial preload applied to the shaft on the sensor, so that the resultant force acting on the sensor was reduced. The contact area of two sensing films was continuously reduced, causing the resistance to increase as shown in A periodic alternating load was applied to the measured component through the fatigue testing machine. The signal conversion and transmission were realized through the transmitter and data acquisition card. A physical diagram of the test device and related components was shown in (1) Fatigue testing machineModel INSTRON-8801, loading range: 0~100 kN; Frequency range: 1~10 Hz; manufacturer: Instron (Shanghai) Test Equipment Trading Co., Ltd. ;(2) Polymer-based flexible piezo-resistive sensorThe substrate of sensing film was PDMS matrix filled with carbon fibers in a certain proportion. The upper film was a cubic structure with a size of 40 mm × 10 mm × 1 mm (length × width × height); The lower film was divided into two layers, where the lower layer was a cubic structure in the same size with the upper film and the upper layer was a micro-triangular groove array with a micro-groove size of 0.5 mm × 1.5 mm.(3) Dumbbell-shaped rubber high-elastic spring componentThe material was nitrile rubber with a shore hardness of 65~75 A. Elastic modulus 2.80 MPa. A definite ratio of carbon black was also filled.(4) Preloading element—sealing rubber ringThe material was waterproof nitrile rubber with a thickness of 5 mm and an outer diameter of 150 mm.(5) Signal transmitterModel KL-N3511, input range 100–3000 Ω, output range 4~20 mA; manufacturer: Beijing Kunlun Coast Sensing Technology Co., Ltd.;(6) Data acquisition card:Model USB-1608G, 16-bit conversion accuracy, standard current signal input, 4~20 mA, frequency 10 HZ; manufacturer: Shanghai Chengke Electromechanical Equipment Co., Ltd. ;(7) Host computer processing systemHardware CPU: ATmega328, the PC software system was Arduino (based on the C language). Serial communication with the data acquisition card was achieved through USB connection.Components (2), (3), and (4) were packaged as shown in In order to verify the stability and reliability of the flexible sensor under cyclic load, the static load test and the dynamic alternating load test were performed in the actual working simulation environment of 10 kN to 60 kN.Under the static experiment, the output characteristics of the sensor were tested at the extreme load of 10 kN and 60 kN respectively. The stability and repeatability were analyzed by multiple sampling. It can be seen from The rapid change of the fixed frequency of the load in the dynamic test was distinguished, followed by the static loading and unloading experiment. The experiment started with the minimum load of 10 kN, and the load increased by 10 kN every 3 s, and then slowly loaded to the maximum load of 60 kN, and then unloaded to 10 kN in the same way, and recorded the data values of each point. Then, under the condition that the sensor was not taken out, 20 repeated tests were carried out, and the average value of 10 consecutive samples was randomly selected to calculate the average value. Loading-unloading resistance output characteristic curve was obtained as shown in As can be seen from the above figure, during the loading and unloading process, the output resistance of the sensor and the load of the device under test largely changed linearly. The resistance of the loading and unloading process was in the range of 310–602 Ω and 331–604 Ω respectively. Meanwhile, the sensitivity was 171 N/Ω and 183 N/Ω respectively. In addition, during the unloading process, as the applied load was gradually reduced, the backlash error gradually increased, and the return error reached a maximum value of 25.01 Ω at 10 kN, and the return error rate of change was 6.34%. In comparison, the two values were greater than the maximum return error of 3.56 Ω and return error rate of change of 0.51% at the 60 kN. Due to the change time of the loading frequency was less than the elastic recovery time of the flexible sensor, so that the error accuracy of the flexible sensor was reduced at the minimum load, and the fluctuation range of the wave at the valley was larger than that of the peak. This part will be more intuitive in the dynamic test.Unlike the static test condition, the fatigue testing machine performed a periodic dynamic load test with a frequency of 3 Hz and an alternating load of 10 kN to 60 kN sine wave, and obtained the load curve F-t and the corresponding sensor resistance output curve R-t as shown in Under the dynamic alternating load, the average sample resistance at the extreme load of the sensor was in a range of 311.37~624.15 Ω. Minimum resistance was between 310 Ω and 331 Ω in static loading and unloading experimental data, and the maximum resistance exceeded 2% in the experimental static range. This was because the cumulative error caused by the polymer-based flexible sensor that produces maximum deformation under maximum alternating load but cannot be fully recovered. By sampling the resistance values corresponding to the minimum and maximum loads several times in succession, the output repeatability characteristics of the polymer flexible sensor under dynamic alternating load were analyzed. After the sampled values were digitally filtered, the resistance peak-to-valley curve of the flexible sensor under dynamic loading is obtained, as shown in It can be seen from Based on the above theoretical analysis and experimental investigation, it was verified that the polymer-based flexible sensor can maintain the synchronous deformation with the measured component when the load was applied, and the output resistance had a phase-matching relationship with the periodic alternating load. Under the load of 3 Hz and 10 kN to 60 kN, the sensor shows a linear variation between resistance and load. The resistance and sensitivity of dynamic and static load was in the range of 310~624.15 Ω and 171–183 N/Ω respectively, while the accuracy fluctuation range was within ±7%. In this work, the sensor based on the forced assembly method, which has certain measurement accuracy and repeatability, can meet the stress test of actual working conditions, and broke the deformation limitation of the elastic component for the traditional mechanical sensor. However, the flexible sensor had a certain zero drift due to the process error during packaging. Furthermore, due to the influence of the material resilience, the backlash error, which was difficult to eliminate, was generated at the extreme load and was more obvious at the minimum value, which gradually affected the repeatability of the test process. In addition, in the actual application process, it was necessary to consider the influence and compensation of the environmental factors such as the temperature on signal conversion and acquisition processing.


Based on the numerical corrosion simulation, it was confirmed that decreasing the number and size of IMPs was favorable for improving the corrosion resistance of the Al alloy due to the reduction of the galvanic effect. In addition, Al3Zr was found to be insignificant in promoting galvanic corrosion within the Al matrix. Thus, Zr is an advantageous alloying element for improving the corrosion resistance of the Al alloy.Corrosion resistance of Zr that has been added to an Al alloy (U1070) is higher than that of a commercial Al alloy (A1070). A decreasing number and size of Al Applications of aluminum (Al) alloys have expanded across numerous industries due to their desirable properties, including their light weight, high heat conduction, and favorable electrical and mechanical characteristics . One typThe Al alloy is composed of multi-element, which influences the corrosion resistance of the Al alloy. The concept of microgalvanic corrosion between the Al matrix and the intermetallic particles (IMPs) is the most common corrosion mechanism for the Al alloy ,12,13,14Thus, in order to improve the corrosion resistance of the Al alloy, the control and modification of IMPs in the Al alloy are important concepts for consideration. In the 1xxx series of Al alloy, the precipitated IMPs are almost related to the impurity elements. Especially, iron (Fe) is the most harmful impurity in Al, and is always present in alloys made from commercially pure base materials ,19. Sinc3Zr phase. Although the grain refinement effect has been researched by various institutes and universities, the influence of the refinement after adding Zr to the corrosion resistance of Al has not yet been considered. Also, the effect of Zr on the distribution of the Al–Fe IMPs, which are the major cause of microgalvanic corrosion in the Al alloy, requires further research. Meanwhile, the corrosion potential of Al3Zr IMPs is very close to that of pure Al in high salt electrolyte conditions  and numerical simulations in various IMP distribution situations were conducted. In addition, the identification of Al–Fe and Al–Zr IMPs was verified by scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and transmission electron microscopy (TEM).In previous studies, the effect of zirconium (Zr) on the grain refinement in Al has been investigated ,32, withTo evaluate the effects of Zr on IMPs in the Al matrix, two tubes consisting of Al alloys (A1070 and U1070) were prepared by casting and mechanical extrusion processes. Although Zr was added in U1070 to investigate the Zr effect, it had the same concentration of Fe, Si, and Cu as the A1070 commercial Al tube. In the casting process, pure Al ingot (99.9%) and three mother alloys  were charged into a graphite crucible at 710 °C. After all of the components were melted, the degassing process was carried out by nitrogen gas purging. Then, mechanical agitation was performed to uniformly mix all of the alloying elements. Molten metals were injected into the 20-cm diameter of a cylindrical mold and air-cooled. Subsequently, the mold was subjected to a homogenization treatment at 490 °C for 10 h. The chemical composition of both Al alloys was analyzed using ICP-MS with Agilent 7500 , as shown in 2 unmasked. The prepared specimens were exposed to a salt water–acetic acid solution at 47 °C under the aerated condition, which is based on ASTM G85 [SCE. After polarization tests, the cross-section of both specimens was observed using an optical microscope. EIS tests were performed at an OCP in the test solution to investigate the surface properties. The frequency range of the EIS tests was from 100 kHz to 10 mHz, with an alternating current amplitude of ±10 mV. The impedance plots were interpreted on the basis of an equivalent circuit using a suitable fitting procedure by use of the ZsimpWin software . Each test was carried out in three replicates to ensure its reproducibility.To evaluate the corrosion resistance of two Al alloys , a potentiodynamic polarization test and EIS were conducted by use of multi-potentiostat/galvanostat instrument VSP-300s . A three-electrode cell was constructed with the Al alloys as the working electrode (WE), two pure graphite rods as the counter electrode (CE), and a saturated calomel electrode (SCE) as the reference electrode (RE). Prior to the electrochemical tests, the Al specimens were abraded with SiC paper with grit sizes from 220 to 600. The prepared tubes were then covered with silicone rubber, leaving an area of 0.09 cmASTM G85 . Table 22O3) solution. Prior to HR-TEM analysis, the specimen was sliced via the machining and ion milling processes to yield thin specimens (10 μm) without thermal influence.The distribution and composition of IMPs are important factors that are related to the corrosion resistance of the Al alloy. Thus, in order to analyze the IMPs in both Al alloys, various surface analyses were performed in this study. First, the distribution of the IMPs in the Al alloy  was observed via field emission EPMA (FE-EPMA) in a JXA-5830F . In addition, energy dispersion spectroscopy (EDS), and high-resolution TEM (HR-TEM) in JEM-ARM300F  were performed for the detailed observation of the size, shape, and composition of the IMPs. Prior to FE-EPMA analysis, the specimen surfaces were polished with a 0.03-μm alumina  was used in this study.Ω), and is surrounded by the surface of the electrolyte Γn, the surface of the Al matrix Γa, and the surfaces of the IMPs Γb and Γc. The electrolyte of conductivity (σ) is uniform over the whole domain, and there is no current loss. The potential field in the electrolyte domain can be modeled by use of the Laplace equation, as follows [The schematic boundary condition for the corrosion simulation in this study is shown in  follows :(1)∇2Φ=Φ is the electrical potential, which is the potential relative to a reference electrode.Here, The Laplace equation is solved using the following boundary conditions:Γ is the entire surface of the electrolyte domain, which includes Γn (electrolyte surface), Γa (Al matrix), Γb (IMP1), and Γc (IMP2). Additionally, fa(Φa), fb(Φb), and fc(Φc) are nonlinear functions on each surface that represent the polarization behavior of each part. Based on this, the potential and current over the whole surface can be calculated.Here, 3Fe and Al3Zr, because Al3Fe is a significant IMP for microgalvanic corrosion in 1xxx Al alloys, and the Zr effect is the main focus of this study. Generally, the anodic Tafel slope of Al in salt water is very low due to the fast anodic reaction, while the cathodic Tafel slope in an aerated environment is high due to the diffusion-limited current caused by oxygen diffusion. Thus, the Tafel slopes that were used for the corrosion simulation consider both the anodic and cathodic properties of Al. Detailed conditions for the corrosion simulation model are listed in IMP distribution models for corrosion simulation were created using the Rhinoceros 3D drawing software . Three cases were considered for the detailed interpretation of corrosion between the IMPs and the Al matrix. Ecorr) and corrosion current density (icorr) of U1070 were both lower than those of A1070. As shown in the schematic Tafel slopes in Ecorr and icorr for U1070. This finding implies that the cathodic reaction intensity was reduced in the case of U1070. The cross-sectional morphologies of both specimens were observed after the polarization tests  equivalent circuit was used in this study. The CPE exponent measures the deviation from the idea capacitive behavior [dlC) was calculated by use of the following Equation (6) [maxf is the frequency at which the imaginary component of the impedance reaches the maximum value. The Rct of U1070 is higher than that of A1070, indicating that the corrosion resistance of U1070 is higher. These results correlate well with the results of the polarization curve.In Nyquist plots of A1070 and U1070 , the diabehavior ,40,41. Ttion (6) :(6)Cdl=2 in both specimens  the small size of IMPs; (2) decreasing the number of IMPs; and (3) a lower difference in the corrosion potential between the Al matrix and the IMPs.For the Al3Zr IMPs c, the ma3Zr IMPs was decreased. These findings regarding corrosion simulation imply that the corrosion current density decrease in 3Zr IMPs do not affect the galvanic corrosion of the Al alloy. Thus, the addition of Zr to an Al alloy is beneficial for improving corrosion resistance, as it reduces the size and number of the IMPs.The above was confirmed by measurement of the total current from the Al matrix in each simulation case . Total c3Fe IMPs was found to be decreased, and a decreasing number of IMPs were observed in U1070. A case study of numerical corrosion simulation revealed that decreasing the number and size of IMPs is favorable for reducing the galvanic corrosion between the IMPs and the Al matrix. Also, the effect of Al3Zr IMPs on the galvanic corrosion of the Al alloy is insignificant as a result of the reduced difference in the corrosion potential between the IMPs and the Al matrix. In summary, the addition of Zr to an Al alloy has a very positive effect in terms of the corrosion resistance, because it decreased the galvanic corrosion effect between the IMPs and the Al matrix by eliciting a decreasing number and size of IMPs.The Zr effect on the corrosion behavior of an Al alloy (1xxx series) was investigated in this study by the potentiodynamic polarization test and EIS. Additionally, FE-EPMA and FE-TEM were conducted to determine the effect of IMPs on an Al matrix, followed by numerical corrosion simulation to investigate the influence of IMPs as a function of distribution and size. In the corrosion tests, the addition of Zr to an Al alloy (U1070) increased the corrosion resistance, indicating that Zr has a beneficial effect on the corrosion resistance of the Al alloy. From the FE-EPMA and FE-TEM analyses, the size of Al