rss_2.0Physics FeedSciendo RSS Feed for Physics Feed the skin biophysical parameters among coronavirus patients for three days in a row: a preliminary study<abstract> <title style='display:none'>Abstract</title> <p>The coronavirus epidemic 2019 is spreading all over the world now. Several parameters are used to monitor the status of hospitalized patients; however, monitoring variations in biophysical properties of the skin has not been investigated yet. In this preliminary study, we seek to monitor skin biophysical parameters among coronavirus patients for three days in a row. Skin moisture, pH, sebum, and temperature during the three days were monitored in 30 coronavirus patients by using non-invasive portable instruments. Skin biophysical parameters were increased on the third day of monitoring compared to the first one. In addition, the increase in both skin moisture and temperature were statistically significant. According to the results of this preliminary study, skin biophysical parameters changed (increased) during the specified period in which the patients were monitored. However, changes in skin sebum content and pH were not significant. These skin parameters need to be further investigated until we know their indication ability for the health condition of coronavirus patients in clinical applications.</p></abstract>ARTICLE2022-05-20T00:00:00.000+00:00Influence of acute water ingestion and prolonged standing on raw bioimpedance and subsequent body fluid and composition estimates<abstract> <title style='display:none'>Abstract</title> <p>This study evaluated the influence of acute water ingestion and maintaining an upright posture on raw bioimpedance and subsequent estimates of body fluids and composition. Twenty healthy adults participated in a randomized crossover study. In both conditions, an overnight food and fluid fast was followed by an initial multi-frequency bioimpedance assessment (InBody 770). Participants then ingested 11 mL/kg of water (water condition) or did not (control condition) during a 5-minute period. Thereafter, bioimpedance assessments were performed every 10 minutes for one hour with participants remaining upright throughout. Linear mixed effects models were used to examine the influence of condition and time on raw bioimpedance, body fluids, and body composition. Water consumption increased impedance of the arms but not trunk or legs. However, drift in leg impedance was observed, with decreasing values over time in both conditions. No effects of condition on body fluids were detected, but total body water and intracellular water decreased by ~0.5 kg over time in both conditions. Correspondingly, lean body mass did not differ between conditions but decreased over the measurement duration. The increase in body mass in the water condition was detected exclusively as fat mass, with final fat mass values ~1.3 kg higher than baseline and also higher than the control condition. Acute water ingestion and prolonged standing exert practically meaningful effects on relevant bioimpedance variables quantified by a modern, vertical multi-frequency analyzer. These findings have implications for pre-assessment standardization, methodological reporting, and interpretation of assessments.</p></abstract>ARTICLE2022-05-20T00:00:00.000+00:00A contrastive study on the production of double vowels in Mandarin<abstract> <title style='display:none'>Abstract</title> <p>The concept of ‘global village’ has linked all countries in the world as a whole. The exchanges and cooperation between different countries in politics, economy, culture, and education are becoming more and more frequent. To master a language, the study of its pronunciation is crucial. Based on the above considerations, this paper uses the Chinese pronunciation corpus of 30 learners and 10 Chinese native speakers as basic data to discuss the pronunciation patterns of learners’ mandarin diphthongs and their similarities to standard pronunciations. In this paper, by using the theory and methods of experimental phonetics, comparative analysis and error analysis, we exam and analyse the acoustic features of different levels of learners in the learning process, and the pronunciation and bias of learners’ mandarin diphthongs are obtained. From the experimental results, it can be seen that all three groups of learners have some difficulties in pronunciation of mandarin diphthongs. In particular, the learners have the greatest differences to standard pronunciations when pronouncing the diphthongs [ua] and [uo]. And some important rules and conclusions are summarised through experiments. This provides an important reference for learners to solve the problems of diphthongs pronunciation in Chinese speech synthesis and recognition.</p> </abstract>ARTICLE2022-04-08T00:00:00.000+00:00Influence of PEG-coated Bismuth Oxide Nanoparticles on ROS Generation by Electron Beam Radiotherapy<abstract> <title style='display:none'>Abstract</title> <p><italic>Introduction:</italic> Nanoparticles (NPs) have been proven to enhance radiotherapy doses as radiosensitizers. The introduction of coating materials such as polyethylene glycol (PEG) to NPs could impact the NPs’ biocompatibility and their effectiveness as radiosensitizers. Optimization of surface coating is a crucial element to ensure the successful application of NPs as a radiosensitizer in radiotherapy. This study aims to investigate the influence of bismuth oxide NPs (BiONPs) coated with PEG on reactive oxygen species (ROS) generation on HeLa cervical cancer cell line.</p> <p><italic>Material and methods:</italic> Different PEG concentrations (0.05, 0.10, 0.15 and 0.20 mM) were used in the synthesis of the NPs. The treated cells were irradiated with 6 and 12 MeV electron beams with a delivered dose of 3 Gy. The reactive oxygen species (ROS) generation was measured immediately after and 3 hours after irradiation.</p> <p><italic>Results:</italic> The intracellular ROS generation was found to be slightly influenced by electron beam energy and independent of the PEG concentrations. Linear increments of ROS percentages over the 3 hours of incubation time were observed.</p> <p><italic>Conclusions:</italic> Finally, the PEG coating might not substantially affect the ROS generated and thus emphasizing the functionalized BiONPs application as the radiosensitizer for electron beam therapy.</p> </abstract>ARTICLE2022-05-06T00:00:00.000+00:00Evaluation and risk factors of volume and dose differences of selected structures in patients with head and neck cancer treated on Helical TomoTherapy by using Deformable Image Registration tool<abstract> <title style='display:none'>Abstract</title> <p><italic>Introduction:</italic> The aim of this study was the evaluation of volume and dose differences in selected structures in patients with head and neck cancer during treatment on Helical TomoTherapy (HT) using a commercially available deformable image registration (DIR) tool. We attempted to identify anatomical and clinical predictive factors for significant volume changes probability.</p> <p><italic>Material and methods:</italic> According to our institutional protocol, we retrospectively evaluated the group of 20 H&amp;N cancer patients treated with HT who received Adaptive Radiotherapy (ART) due to soft tissue alterations spotted on daily MVCT. We compared volumes on initial computed tomography (iCT) and replanning computed tomography (rCT) for clinical target volumes (CTV) – CTV1 (the primary tumor) and CTV2 (metastatic lymph nodes), parotid glands (PG) and body contour (B-body). To estimate the planned and delivered dose discrepancy, the dose from the original plan was registered and deformed to create a simulation of dose distribution on rCT (DIR-rCT).</p> <p><italic>Results:</italic> The decision to replan was made at the 4th week of RT (N = 6; 30%). The average volume reduction in parotid right PG[R] and left PG[L] was 4.37 cc (18.9%) (p &lt; 0.001) and 3.77 cc (16.8%) (p = 0.004), respectively. In N = 13/20 cases, the delivered dose was greater than the planned dose for PG[R] of mean 3 Gy (p &lt; 0.001), and in N = 6/20 patients for PG[L] the mean of 3.6 Gy (p = 0.031). Multivariate regression analysis showed a very strong predictor explaining 88% (R<sup>2</sup> = 0.88) and 83% (R<sup>2</sup> = 0.83) of the variance based on the mean dose of iPG[R] and iPG[L] (p &lt; 0.001), respectively. No statistically significant correlation between volume changes and risk factors was found.</p> <p><italic>Conclusions:</italic> Dosimetric changes to the target demonstrated the validity of replanning. A DIR tool can be successfully used for dose deformation and ART qualification, significantly reducing the workload of radiotherapy centers. In addition, the mean dose for PG was a significant predictor that may indicate the need for a replan.</p> </abstract>ARTICLE2022-05-06T00:00:00.000+00:00ARMA analysis of the green innovation technology of core enterprises under the ecosystem – Time series data<abstract> <title style='display:none'>Abstract</title> <p>From the perspective of innovation ecology, the green innovation of core enterprises is a key to high-quality economic development. This paper researches BYD, makes a discussion on the evolution and characteristics of green innovation, and clarifies the driving force of green innovation of core enterprises in the green innovation ecosystem. In addition, the 2002–2019 green patent authorisation data of BYD is selected as the green output indicator of the core enterprise. And through testing the data, the findings are that the perturbation term <italic>ε</italic> is white noise, which meets the zero expectation E(<italic>ε<sub>t</sub></italic>) = 0, and the same variance Var(<italic>ε<sub>t</sub></italic>) = <italic>σ</italic><sup>2</sup> and that there is no autocorrelation Cov(<italic>ε<sub>t</sub></italic>, <italic>ε<sub>s</sub></italic>) = 0, t ≠ s. The ARMA model is hence constructed for analysis. Through analysis, conclusions are drawn that when the core enterprises and other entities in the green innovation ecosystem collaborate to innovate, the complexity and dynamics could be found in the green innovation evolution process and that as an important driving force for green innovation, innovation input not only raises current green output but also facilitates future green output.</p> </abstract>ARTICLE2022-03-31T00:00:00.000+00:00Study on the crushing mechanism and parameters of the two-flow crusher<abstract> <title style='display:none'>Abstract</title> <p>Based on a Chinese enterprise's single-mouth crusher, the ‘waterfall flow’ inlet crusher is developed from a foreign two-flow crusher. The two-inlet crushing mode has advantages of continuous particle feeding, controlled particle flow and low wear of housing. By analysing the working principle of the equipment, the three-dimensional model of the crusher is established. Based on the discrete element method, the simulation data are obtained by EDEM simulation software. The crushing energy, the wear of the housing and the counter boards are analysed to obtain the optimal parameters. The crushing efficiency is significantly improved and the wear of the housing is controlled to some extent. The overall performance of the crusher is improved and the cost is reduced.</p> </abstract>ARTICLE2022-03-31T00:00:00.000+00:00Development of main functional modules for MVB and its application in rail transit<abstract> <title style='display:none'>Abstract</title> <p>In this work, multi-function vehicle bus (MVB) controller-based Field Programmable Gate Array (FPGA) and MVB manager based on the real-time multitasking operating system were explored and developed. The function of the MVB controller data link layer was realised by using FPGA. The embedded real-time multitasking operating system uCOS-II was applied to the development of MVB manager’s processing data, device state management, message data and bus management function. The network consistency test was performed to validate data communication of MVB link layer control protocol and the management function of MVB manager; the equipment was shown to be compatible with each other and met the requirements of IEC61375-1.</p> </abstract>ARTICLE2022-04-29T00:00:00.000+00:00Editors’ Note Public Health Gains From German Smokers Switching to Reduced-Risk Alternatives: Results From Population Health Impact Modelling<abstract> <title style='display:none'>Summary</title> <sec><title style='display:none'>Background</title> <p>Smoking is associated with cancer and cardio-respiratory mortality. Reducing smoking prevalence will lead to fewer deaths and more life-years. Here, we estimate the impact of hypothetical introduction of reduced-risk products (heat-not-burn products and e-cigarettes) in Germany from 1995 to 2015 on mortality from lung cancer, chronic obstructive pulmonary disease, ischaemic heart disease, and stroke in men and women aged 30–79 years.</p> </sec> <sec><title style='display:none'>Methods</title> <p>We used a previously described population health impact model, with individuals with a defined baseline cigarette smoking distribution followed under a “Null Scenario”, with reduced-risk products never introduced, and various “Alternative Scenarios” where they are. Transition probabilities allow product use to change annually, with the individual product histories allowing estimation of risks, relative to never users, which are then used to estimate reductions in deaths and life-years lost for each Alternative Scenario.</p> </sec> <sec><title style='display:none'>Results</title> <p>In the Null Scenario, we estimated 852,000 deaths from cigarette smoking (42,600 per year), with 8.61 million life-years lost. Had everyone ceased smoking in 1995, and with no use of reduced-risk products, these numbers would reduce by 217,000 and 2.88 million. Compared to the Null Scenario, the estimated reductions would be 159,000 and 2.06 million with an immediate complete switch to heat-not-burn products and 179,000 and 2.34 million with 50% of smokers immediately switching to heat-not-burn products and 50% to e-cigarettes. In four Scenarios with a more gradual switch, the estimated decreases were 39,800–81,000 deaths and 0.50–1.05 million life-years, representing 17.5%–37.5% of the effect of immediate cessation in 1995. These estimates assume that switching to heat-not-burn products and e-cigarettes involves risk decreases of 80% and 95% of those from quitting, respectively. The reductions in mortality would be greater with more diseases and a wider age range considered or with a longer follow-up period, as the decreases increased markedly with time. Various limitations are discussed, none affecting the conclusion that introducing these new products into Germany in 1995 could have substantially reduced deaths and life-years lost.</p> </sec> <sec><title style='display:none'>Conclusions</title> <p>Deaths from cigarette smoking could be substantially reduced not only by cessation but additionally by switching to reduced-risk products. Respective public health campaigns might increase such switching.</p> </sec> </abstract>ARTICLE2022-05-05T00:00:00.000+00:00Estimated Public Health Gains From Smokers in Germany Switching to Reduced-Risk Alternatives: Results From Population Health Impact Modelling by Socioeconomic Group<abstract> <title style='display:none'>Summary</title> <sec><title style='display:none'>Background</title> <p>We previously estimated the impact of introducing heat-not-burn products and e-cigarettes in Germany on smoking-related disease mortality in men and women aged 30–79 years between 1995 and 2015. Here, we estimate the impact by socioeconomic group.</p> </sec> <sec><title style='display:none'>Methods</title> <p>Individuals with a defined baseline cigarette smoking distribution were followed under a “Null Scenario” (no reduced-risk products) and “Alternative Scenarios” (reduced-risk products introduced). Transition probabilities allowed estimation of annual product use changes, with individual product histories used to estimate reductions in deaths and life-years lost. Here, however, individuals were classified into two socioeconomic groups defined by income and education, with allowance for variation by group in initial smoking prevalence and the probability of changing product use, or of changing socioeconomic group.</p> </sec> <sec><title style='display:none'>Results</title> <p>With no allowance for socioeconomic group, deaths would have reduced by 217,000 (from 852,000 for continued smoking) had everyone immediately ceased smoking in 1995 and by 40,000 to 179,000 had one or two types of reduced-risk products – the heat-not-burn product and the e-cigarette – been adopted by smokers to varying extents. With such allowance, we estimate substantial drops in each socioeconomic group. Where all cigarette smokers switched immediately, half of them to heat-not-burn products, half to e-cigarettes, the estimated drops in deaths were 60,000 in group A (higher socioeconomic group) and 122,000 in group B (lower), about 82% of the drops associated with immediate cessation (73,000 in A and 148,000 in B). With more gradual conversion, the drops were 26,648 in A and 53,000 in B, about 35% of those from cessation. The drops in deaths and life-years saved were about 2 and 1.5 times higher in group B, respectively, associated with its greater numbers, older age, and higher smoking prevalence. The estimated reductions would increase upon considering more diseases, a wider age range, or longer follow-up. Methodological limitations would not affect the conclusion that introducing these products in 1995 in Germany could have substantially reduced deaths and life-years lost in both groups, more so in B.</p> </sec> <sec><title style='display:none'>Conclusions</title> <p>Although cessation is optimal for reducing mortality, switching to reduced-risk products also provides substantial health gains. A public health approach encouraging lower socioeconomic group smokers to switch to reduced-risk products could diminish smoking-related health inequalities relative to continued smoking.</p> </sec> </abstract>ARTICLE2022-05-05T00:00:00.000+00:00A Simultaneous Analytical Method to Profile Non-Volatile Components with Low Polarity Elucidating Differences Between Tobacco Leaves Using Atmospheric Pressure Chemical Ionization Mass Spectrometry Detection<abstract> <title style='display:none'>Summary</title> <p>A comprehensive analytical method using liquid chromatography atmospheric pressure chemical ionization mass spectrometry detector (LC/APCI-MSD) was developed to determine key non-volatile components with low polarity elucidating holistic difference among tobacco leaves. Nonaqueous reversed-phase chromatography (NARPC) using organic solvent ensured simultaneous separation of various components with low polarity in tobacco resin. Application of full-scan mode to APCI-MSD hyphenated with NARPC enabled simultaneous detection of numerous intense product ions given by APCI interface. Parameters for data processing to filter, feature and align peaks were adjusted in order to strike a balance between comprehensiveness and reproducibility in analysis. 63 types of components such as solanesols, chlorophylls, phytosterols, triacylglycerols, solanachromene and others were determined on total ion chromatograms according to authentic components, wavelength spectrum and mass spectrum. The whole area of identified entities among the ones detected on total ion chromatogram reached to over 60% and major entities among those identified showed favorable linearity of determination coefficient of over 0.99. The developed method and data processing procedure were therefore considered feasible for subsequent multivariate analysis. Data matrix consisting of a number of entities was then subjected to principal component analysis (PCA) and hierarchical clustering analysis. Cultivars of tobacco leaves were distributed far from each cultivar on PCA score plot and each cluster seemed to be characterized by identified non-volatile components with low polarity. While fluecured Virginia (FCV) was loaded by solanachromene, phytosterol esters and triacylglycerols, free phytosterols and chlorophylls loaded Burley (BLY) and Oriental (ORI) respectively. Consequently the whole methodology consisting of comprehensive method and data processing procedure proved useful to determine key-components among cultivars of tobacco leaves, and was expected to additionally expand coverage that metabolomics study has ensured. [Beitr. Tabakforsch. Int. 27 (2016) 60-73]</p> </abstract>ARTICLE2016-05-18T00:00:00.000+00:00Influence of Type and Amount of Carbon in Cigarette Filters on Smokers’ Mouth Level Exposure to “Tar”, Nicotine, 1,3-Butadiene, Benzene, Toluene, Isoprene, and Acrylonitrile<abstract> <title style='display:none'>Summary</title> <p>Activated carbons are effective adsorbents for many volatile organic compounds and are used in cigarette filters to remove selected smoke toxicants. Polymer-derived carbon is more effective in removing many vapour phase toxicants found in cigarette smoke than coconut-shell-derived carbon. We compared mouth-level exposure to “tar”, nicotine and five vapour phase constituents (1,3- butadiene, benzene, toluene, isoprene, acrylonitrile) in two groups of Romanian smokers of 4-mg or 8-mg International Organization for Standardization (ISO) “tar” bands. Test cigarettes with 4 and 8 mg ISO “tar” were manufactured for the study with two target levels of polymer-derived carbon (30 mg and 56 mg), along with control cigarettes containing a target level of 56 mg of coconut-shell-derived carbon in both “tar” bands. No significant differences were found between mouth-level exposure to “tar” or nicotine yields obtained from control and test products (p &gt; 0.05) in either ISO “tar” band. Mouth-level exposure to each of the five vapour phase constituents was significantly lower from the test products with polymer-derived carbon (p &lt; 0.0001) than from control cigarettes with coconut-shell-derived carbon, by an average of 25% with 30 mg polymer-derived carbon and around 50% with 56 mg. [Beitr. Tabakforsch. Int. 27 (2016) 40-53]</p> </abstract>ARTICLE2016-05-18T00:00:00.000+00:00Nicotine Analysis in Several Non-Tobacco Plant Materials<abstract> <title style='display:none'>Summary</title> <p>Present study describes the determination of nicotine in various plant samples with a low content of this compound. Nicotine is found naturally in plants from the Solanaceae family. The plants from Nicotiana genus contain large levels of nicotine. However, only low levels are present in plants from Solanum genus including potato, tomato, eggplant, and from Capsicum genus, which are used as food. Because the levels of nicotine in these materials are in the range of parts per billion, the measurements are difficult and the results are very different from study to study. The present study evaluated the level of nicotine in a number of plants (fruits, roots, leaves, tubers) from Solanaceae family (not including Nicotiana genus) and from several other vegetables commonly used as food. The analysis consisted of the treatment of plant material with an aqueous solution 5% NaOH at 70°C for 30 min, followed by extraction with TBME containing d<sub>3</sub>-nicotine as an internal standard. The TBME organic layer was analyzed on a 7890B/7000C GC-MS/MS system with a 30 m × 0.25 mm, 0.25 μm film CAM column. The MS/MS system worked in MRM positive ionization mode monitoring the transition 162 - 84 for nicotine and 165 - 87 for d<sub>3</sub>-nicotine. Particular attention was given to the preservation of the intact levels of nicotine in the plant material. The plant material was analyzed as is, without drying and with minimal exposure to contaminations. Separately, the moisture of the plant material was measured in order to report the nicotine level on a dry-basis. Levels of nicotine around 180 ng/g dry material were obtained for tomatoes and eggplant (fruit) and lower levels were obtained for green pepper and potato. Similar levels to that in the tomato fruit were detected in tomato leaves. Materials from other plant families also showed traces of nicotine. [Beitr. Tabakforsch. Int. 27 (2016) 54-59]</p> </abstract>ARTICLE2016-05-18T00:00:00.000+00:00Cross-Sectional Relations Between Slim Cigarettes and Smoking Prevalence<abstract> <title style='display:none'>Summary</title> <p>Slim cigarettes were defined in the 2012 draft European Union-Tobacco Product Directive (EU-TPD) as cigarettes with a diameter of less than 7.5mm. Allegations that slim cigarettes may negatively impact tobacco control efforts led the European Commission to propose a ban on them in 2012, which was ultimately rejected. This study investigated whether there is any association between slim cigarettes and smoking prevalence rates, in order to see if these allegations are justified. Data was compiled on the market share of slim cigarettes and smoking prevalence rates from the years 2012, 2006 and 1996. The core 2012 sample (once data limitations were accounted for) consisted of 95 countries. Raw correlations between market shares of slim cigarettes and smoking prevalence rates were first examined, followed by multivariate cross-country regressions where various factors were controlled for. This was done for overall smoking prevalence, as well as for male and female prevalence separately. </p> <p>Although raw correlations between the slim cigarette market share and smoking prevalence were sometimes positive and statistically significant, this result disappeared in all cases except for one when potential confounding factors were fully controlled for. The correlation between slim cigarette market share and smoking prevalence remained significant only for males in 2012 at levels of statistical significance of 10% or above when cultural and socio-economic factors were fully controlled for. Importantly, for females no positive statistically significant correlations between the slim cigarette market share and smoking prevalence were found for any year. The cross-country variation in smoking prevalence was substantially explained by a number of regional and cultural dummies, as well as socio-economic factors. </p> <p>This study has found no indication that a higher market share of slim cigarettes was associated with greater smoking prevalence among females, and has failed to find a strong indication among males, once confounding factors were controlled for. [Beitr. Tabakforsch. Int. 27 (2016) 75-99]</p> </abstract>ARTICLE2016-05-18T00:00:00.000+00:00Medical Devices Management System Based on Blockchain Technology<abstract> <title style='display:none'>Abstract</title> <p>The recent use of digital Distributed Ledger Technology (DLT) in the healthcare domain can surpass the existing limitations in the centralized IT systems, such as the lack of security, access control or immutability of the electronic health information. If we discuss about clinical information, this innovative informatics advance gives back the control to the data owner. In decentralized environments, smart contracts allow trustable agreements grounded by irreversible transactions, which permit transparency and traceability. Moreover, smart contracts are the living heart of the decentralized applications that run on DTL. In this work, our attention is focused on medical equipments that helps health staff to diagnose and treat patients keeping much of their clinical data taken in dynamics. Hence, we propose a smart contract-based decentralized application framework for the management of devices, targeting also medical services, meant to facilitate the interaction of the involved entities. Our testing environment is the Ethereum platform, extensively used recently in the healthcare domain, being itself a smart operating system that allows decentralized applications to run on it.</p> </abstract>ARTICLE2022-04-30T00:00:00.000+00:00Walnut (Juglans Regia): A Review of Phytosanitary Properties and Theirs Mathematical Modeling<abstract> <title style='display:none'>Abstract</title> <p>Walnut (Juglans regia L.) is the most widespread walnut in the world. All parts of the plant are important: bark, leaves, dried and green peel of the fruit, septum, core. The benefits of walnuts are due to the presence of phytochemicals such as flavonoids, carotenoids, alkaloids, polyphenols, etc. In addition to the many benefits that walnut has on our health (antibacterial, antioxidant), it also has important phytosanitary and insecticidal properties. Walnuts can be used because of their plant-friendly properties in the form of biopesticides that are safe and can be a viable, inexpensive and cleaner alternative to synthetic products that can be harmful to the environment. This review paper seeks to bring to the fore the available literature on Juglans regia directed on the properties, antifungals and insecticides with action on plants and antibacterials with action on the human body, as well as mathematical models regarding the multiplication of microorganisms.</p> </abstract>ARTICLE2022-04-30T00:00:00.000+00:00General Considerations Related to the Membrane Material Locking Models ‒ A Short Rewiew<abstract> <title style='display:none'>Abstract</title> <p>The problem of clogging membrane pores has become an area of interest for the vast majority of researchers in the field, because according to the literature, membrane materials are very sensitive when it comes to clogging and blocking pores.</p> <p>Therefore, this paper briefly describes the problems that occur during the process of obstruction the pores of the membrane. Models and characteristics of pore blocking mechanisms have also been developed.</p> <p>It is essential to mention that the principal purpose of the paper, which which consisted to review the simulations and classical models that were optimized, used in the analysis processes of clogging of membrane materials, was successfully fulfilled.</p> <p>According to those mentioned, the combined mathematical models of pore blocking (methods combined with three blocking mechanisms using Hagen-Poiseuille’s law or standard 0-order blocking) have proven to be very effective in describing membrane clogging problems.</p> </abstract>ARTICLE2022-04-30T00:00:00.000+00:00A Review of Metallic Materials Corrosion<abstract> <title style='display:none'>Abstract</title> <p>The present manuscript presents a theoretical study for the corrosion process. Corrosion processes are primed and stimulated in 60% of cases by chemical and biological elements. One of the most used biological elements are: bacteria, actinomycetes, microscopic fungi, algae. Corrosion of a solid body results from the transformation of structural bonds in that body. Less than certain influences (water, oxygen, light, etc.) the atom - which is practically neutral - can lose or gain electrons and it is ionized.</p> <p>Brake pads are affected of corrosion process. The conceptions and mathematical symbols serve as the models building blocks. Authors like, Boz M, and other authors demonstrate in their researches that starting with the concept of number, where every mathematical object is a mathematical model.</p> <p>In practice it is not possible to reproduce some experimental, theoretical conditions related to corrosion processes. These processes are therefore, to some extent, different in terms of the applicability of theoretical laws. From a thermodynamic point of view, metals are not stable and due to corrosion, metals tend to return to the stable form of oxides with the help of oxygen and moisture in the air. For this each metal requires certain ionization energy.</p> <p>When establishing the mathematical model, those characteristics of the modeling object are highlighted, which, on the one hand, are informative, and on the other hand, they admit the mathematical form review.</p> </abstract>ARTICLE2022-04-30T00:00:00.000+00:00Mach’s Principle in the Acoustic World<abstract> <title style='display:none'>Abstract</title> <p>The aim of this paper is to investigate the coupled oscillations of multiple bubbles within a cluster. The interaction between a bubble and the other bubbles in a cluster produces an additional mass. For a fixed number of bubbles and uniformly distributed (<italic>N</italic> ---gt------gt--- 1), in case of a certain value of the bubbles number density, we deduce the relations analogous to the Eddington relation (between the cluster radius and the bubble radius) and the Sciama relation (between the cluster radius and the gravitoacoustic radius) according to Mach’s Principle.</p> </abstract>ARTICLE2022-04-30T00:00:00.000+00:00en-us-1