Contact Points Research Articles

Multipoint Variable parameter compliant control of redundant manipulator based on the equivalent twin model of flexible contact dynamics

To elucidate the dynamic coupling mechanism involved in multipoint/arbitrary point contact during human–robot interactions with redundant manipulators, we introduce a compliant control strategy that adapts to variable parameters. This strategy is based on the flexible contact dynamic equivalent twin system for human–robot interactions. Using the Virtual Elastic Element Representation model for arbitrary point contact dynamics and leveraging the skeleton principle for contact force conversion, we construct a flexible contact dynamic equivalent twin system tailored for redundant manipulators with multipoint/arbitrary point contact capabilities. Within this system, we implement real-time adjustments to the impedance stiffness coefficient in conjunction with the virtual end velocity of the manipulator. We optimize the joint angular velocity of the manipulator while considering the motion allocation of redundant degrees of freedom. This optimization enables multipoint contact variable parameter compliance control for safe human–robot interactions. To validate our approach, we analyze the multipoint contact dynamic model of the redundant manipulator's interaction with humans and assess the feasibility of the variable parameter compliance control method using robot operating system simulations. Ultimately, we verify the effectiveness and practicality of our proposed compliance control method through simulation and experimental results.

Research on the performance optimization of the cam linkage mechanism for marine diesel engines

Abstract In this paper, the impact of friction and wear in the flat bottom mechanism of a diesel engine on the reliability and durability of the valve train is investigated. A method for establishing a dynamic contact model is proposed, including the establishment of the cam profile equation, force analysis at the contact point, calculation of the curvature radius, and derivation of contact stress. Through the derivation of wear depth and structural optimization analysis, the proposed method can be used to optimize the cam profile and improve the service life and work efficiency of the valve train. The results show that the optimized cam follower’s life is increased by 31.8%, and the contact stress is decreased by 16.5%. This study is of great significance for improving the power and efficiency of diesel engines.

Research On the Design of Public Transit Services for The Elderly in China

As China enters an aging society, the elderly in China are increasingly becoming an important user group of public transportation. This study uses service design thinking to optimize the inclusiveness of Chinese elderly people's travel by bus and subway, and explores the feasibility of applying service design thinking to the field of public transportation. This paper adopts the observation method, with Guangzhou and Beijing as the research areas. The researchers conduct service design research based on the entire process of elderly travel, summarize the travel needs and pain points of elderly passengers, optimize the station guidance system, intelligent interface and service platform, make the public transportation service environment more friendly, and thus make the public transportation service environment more inclusive. Analyze the passenger flow, contact points, and stakeholders of the station, draw character portraits and journey maps, and output service design strategies to improve the travel experience of Chinese elderly passengers. In summary, this study aims to improve the convenience of Chinese elderly passengers taking public transportation and provide theoretical support for the transformation and optimization of China's public transportation services.

Real-Time Bus Route and Timing Information System using IoT

This system suggests a user-friendly online interface for accessing real-time routes and schedules of the bus. The system provides the most recent information about bus locations, routes, and anticipated arrival times by utilizing the Internet of Things (IoT) and Global Positioning System (GPS) capabilities. The technology continuously collects position data by installing GPS modules on buses and linking them to an IoT network. After that, the data is sent to a central server for processing and display. The web interface serves as the main point of contact for users, it displays the positions of buses in real-time on a map along with integrated route data. By seeing the real-time position and expected arrival time of approaching buses, passengers may easily plan their journeys by accessing the webpage from any device with an internet connection. In addition to reducing wait times, enhancing customer satisfaction levels, and facilitating better travel arrangements, this gives transportation authorities useful information for optimizing bus routes and schedules.

A study on knowledge, awareness, and practices about eye donation in medical students

Aim: The aim of the study was to assess knowledge, awareness, and practices about eye donation in medical students of medical colleges. Setting: Tertiary Care Centre. Design: This study involves a cross-sectional study. Materials and Methods: A cross-sectional study at a tertiary care center in Western Vidarbha from August 2023 to October 2023, among medical students. Approval from the institutional ethical committee was taken. A total of 538 students participated in the study. After taking consent, data were collected in self-reported questionnaire consisting of questions about the knowledge and awareness of eye donation, the source of their information, willingness for donation, and respective reasons for willingness and nonwillingness. Data were analyzed. Results: Majority of students belonged to the age group between 21 and 30 years. Most were undergraduates, followed by interns and post-graduates. Five hundred and twenty-nine had heard about eye donation mainly through medical personnel. The majority of students believed that eye donation means giving sight to the blind. Most knew the nearest point of contact for eye donation. The answer given by most to the question “What is removed for transplantation?,” was cornea. The most common response to questions about a site for the removal of eyes was the hospital. The majority knew that no monetary benefits were given for donations. Those willing to pledge their eyes wanted to do so to help the blind, and those not willing said objection by family as the main reason among others. Conclusion: After the study, we concluded that awareness about eye donation was good in the students, while knowledge regarding eye donation varied among the students. Willingness to donate showed mixed responses.

Developing a Conceptual Framework for a Person-Centered Approach to Improving Adherence and Outcomes in Lung Cancer Screening: The Engaged Approach to Lung Cancer Screening: A Brief Report

IntroductionTranslating outcomes from randomized trials of lung cancer screening into community practice settings has been challenging. We developed a framework—the Engaged Approach to Lung Cancer Screening (EA-LCS)—for improving adherence and individual and population health outcomes in LCS. MethodsEmploying community-engaged research, we conducted semistructured interviews with LCS program staff (N = 15) and participants (N = 7) and administered brief surveys to understand LCS adherence. We combined our knowledge of LCS implementation with data to formulate the EA-LCS framework, including principles and strategies instrumental for LCS adherence. ResultsProgram staff identified four factors that facilitated adherence: (1) the use of specialized tracking software, (2) the importance of personal connection and a reliable touchpoint, (3) centralized program operations, and (4) standardization/streamlining of reports to participants and clinicians. Participant data identified four factors supporting adherence: (1) a single contact point and information availability, (2) tailored communications, (3) personalized results delivery, and (4) increased scan accessibility. Combined analyses identified three overarching themes in the EA-LCS framework: (1) respect, (2) trust, and (3) engagement. ConclusionsThe EA-LCS conceptual model integrates three foundational principles (person-centeredness, trustworthy relationships, and sustained communications) to enhance LCS adherence. Efforts are underway to translate the EA-LCS framework into materials to support adherence.

Comparison of proximal contact and contours of class II restoration in premolars and molars restored with three different matrix systems using FDI criteria: An in vivo study.

Sectional matrix systems, namely, Garrison and Bioclear with contact rings, are valuable aids to establish proximal contact tightness and contours in Class II composite restorations when compared with the circumferential matrix system Tofflemire. This study aimed to compare the proximal contact and contours of Class II restoration in premolars and molars restored with Tofflemire, Garrison, and Bioclear matrix system by FDI criteria of approximal anatomical form using floss or 25-µm metal blade and radiographic examination. Sixty Class II patients were selected, and a preoperative bitewing radiograph was taken. Initially, caries removal was done by round diamond bur, followed by 245 carbide bur. Samples were divided randomly into three groups based on the type of matrix system used for restoration. Group 1 (n = 20): Tofflemire, Group 2 (n = 20): Garrison matrix system, and Group 3 (n = 20): Bioclear matrix system. Matrix systems were applied according to the manufacturer's instructions, and composite restoration was done. The clinical evaluation of proximal contact and contour was done by a blinded observer immediately after placement of composite restoration using FDI criteria by passing dental floss or 25-µm metal blade, whereas marginal gaps and overhangs were checked using a radiograph. Results were statistically analyzed. The statistical analysis was done using the Statistical Package for the Social Sciences (SPSS for Windows, Version 19.0). Descriptive statistics was calculated as frequency and percentage. The comparison of characteristics of the contact points, contour, and radiographic examination was carried out using the Chi-square test. Multiple comparisons were done by comparing column proportions with Bonferroni adjustments. The level of significance for the present study was fixed at P < 0.05. There were significantly higher proportions of normal contacts in Garrison (60%) and Bioclear (70%) compared to that in the Tofflemire (20%) matrix system (Bioclear > Garrison > Tofflemire). Comparison of contours showed normal contours with Garrison (50%), Bioclear (50%), and Tofflemire (15%) matrix system (Bioclear = Garrison > Tofflemire). In radiographic examination, harmonious transitions between the restoration and the tooth were similar in Garrison (30%) and Bioclear (30%) compared to the Tofflemire (15%) matrix system (Bioclear = Garrison > Tofflemire). Garrison and Bioclear sectional matrix systems established superior contacts and contours than the Tofflemire circumferential system.

An experimental study on the wettability of nanofluids

The wettability of nanofluid is a key factor affecting oil recovery and fluid heat transfer. However, the traditional wettability measurement method consisting in determining the contact angle enables to assess the wettability at a solid–liquid contact point only and not within the continuous detection range. Therefore, in this work, a lateral friction detection system is used to continuously measure the wettability of hydroxylated multi-walled carbon nanotubes/deionized water (MWCNT-OH/DIW) nanofluids on polydimethylsiloxane surfaces. Specifically, MWCNT-OH/DIW nanofluids with various mass fractions are configured, and different surfactants are introduced to regulate the dispersion in deionized water. The results reveal that the surface tension and contact angle decrease simultaneously with the increase in MWCNT-OH/DIW mass fraction. Meanwhile, this change also causes an increase in the lateral friction at the nanofluid/PDMS interface. Furthermore, both sodium dodecyl sulfate and cetyltrimethylammonium bromide (CTAB) as surfactants can effectively reduce its surface tension. Notably, when CTAB is added, the maximum static friction (132.62 μN) exceeds that of SDS (113.13 μN). Therefore, the proposed method opens up new prospects in wettability detection of nanofluids.

Features of Microwave Photoconductance of Quantum Point Contact and Silicon Field-Effect Transistor

Features of Microwave Photoconductance of Quantum Point Contact and Silicon Field-Effect Transistor

Privacy in Community Pharmacies in Saudi Arabia: A Cross-Sectional Study.

Privacy in healthcare is a fundamental right essential to maintain patient confidentiality and trust. Community pharmacies in Saudi Arabia (SA) play a critical role in the healthcare system by providing accessible services and serving as initial points of contact for medical advice. However, the open nature of these settings poses significant challenges in maintaining patient privacy. This cross-sectional study used electronic surveys distributed across various online platforms. The target sample included Saudi adults, with a sample size of 385 participants to achieve 80% statistical power at a 95% confidence interval. The survey comprised demographic questions and sections evaluating perceptions of privacy, the importance of privacy, and personal experiences regarding privacy in community pharmacies. Descriptive statistics and logistic regression models were used for the analysis. A total of 511 responses were obtained. The mean age was 33.5 years, with an almost equal distribution of males (49.71%) and females (50.29%). Most participants held a bachelor's degree or higher (78.67%). Privacy perceptions varied, with only 9.0% strongly agreeing that there was a private space for consultations, while 64.0% felt that the design of community pharmacies did not adequately consider patient privacy, and 86.9% reported that conversations could be overheard. Privacy concerns were notable, with almost one-half of the participants (47.6%) having concerns about privacy and 56.6% doubting the confidentiality of their health information. Moreover, 17.6% reported being asked for unnecessary personal information when buying medication, and 56.2% admitted to avoiding discussing a health problem with the pharmacist due to privacy concerns. Experiences of privacy breaches were reported by 15.7% of respondents. Logistic regression analysis revealed that the availability of private space in the pharmacy and patients feeling that the pharmacy respects their privacy were associated with a lower likelihood of avoiding discussions with pharmacists due to privacy concerns (OR = 0.758, CI = 0.599-0.0957 and OR = 0.715, CI = 0.542-0.945 respectively) Conversely, greater privacy concerns and previous privacy breaches significantly increased the likelihood of avoiding discussions with pharmacists in the community pharmacy (OR = 1.657, CI = 1.317-2.102 and OR = 4.127, CI = 1.886-9.821 respectively). This study highlights the significant concerns regarding privacy practices in community pharmacies in SA. Thus, there is a need for standards to improve privacy in community pharmacies, such as mandating the need for private consultation areas and enhanced staff training on handling privacy-related issues. Addressing the issue of privacy is crucial for maintaining patient trust, improving healthcare service quality, and ensuring effective patient-pharmacist interactions.

Admission Rate of Patients Visiting Emergency Department in a Tertiary Care Center in Kathmandu

Introduction: Emergency departments serve as the initial point of contact for patients with a wide range of conditions. Not all patients visiting get admitted to the hospital. The admission rate varies from 20% in the United States to 40.83% in Nepal. Given the variability in these results across different regions, there is a need to better understand the admission rates from the Emergency Department.Methods: A descriptive cross-sectional study was conducted after obtaining ethical approval( Reference Number: 58 (6-11)E2 081/082) in the Emergency Department of a tertiary health care center. Retrospective data was collected from the data register. The data from April 2023 to April 2024 was collected. A sample size of 222 was calculated and convenience sampling was done. Demographic details like age, sex, and data regarding admission status were collected. Data was collected in MS Excel and was analyzed using JASP software. Results: Out of 222 patients that presented to the emergency department, 53 (23.87%)(18.26-29.47,95 % Confidence Interval) were admitted to the ward or intensive care unit of the hospital, whereas 167 (75.23) got discharged, 1 (0.45%) was brought dead and 1 (0.45%) expired. The median age of patients was 43 (IQR: 26-62). The admission rate of females was 20 (17.24%), whereas for males it was 33 (31.13%).Conclusions: The prevalence of admission of patients visiting the emergency department was higher than similar US based studies. There was a higher percentage of female patients presenting to theemergency department, while those being admitted were mostly males.

Evaluation of wind erosion resistance of EICP solidified desert sand based on response surface methodology

Wind erosion is the primary cause of land desertification in arid and semi-arid regions. Enzyme-induced carbonate precipitation (EICP) will produce a solid coating on the surface of desert sand that inhibits wind erosion. Three critical variables for EICP treatment, including enzyme-cementation ratio A, cementation solution concentration B, and spraying volume of reaction solution C, were evaluated with three wind erosion-resistance indexes (surface strength, calcium carbonate content, and solidified layer thickness) of desert sand, and further optimized with the response surface methodology (RSM). The mass loss of the EICP-treated desert sand was studied by wind tunnel tests with wind speeds of 8–14 m/s and erosion times of 0–30 min. Material composition and microstructure of the EICP precipitates were investigated with X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Results indicate that the three wind erosion-resistance indexes tend to rise with greater A and B values followed by a decline while monotonically increasing with C but the increments decrease when C>5 L/m2. The optimal solidification effect was reached when A=1.082:1, B=1.282 mol/L and C=8.70 L/m2, which corresponds to a maximum wind speed of 14 m/s for solidified desert sand. Large amounts of calcite crystals were produced in the EICP-treated sand and filled soil pores. The particle contacts transform from point contact to surface contact and the enhanced particle bonding induces a more compact soil skeleton. The above experiment evidence corresponds to increased surface strength and wind erosion resistance. The results of this study will provide an experimental foundation for the application of EICP technology to enhance wind erosion resistance of desert sands.

Membrane-Nanoparticle Interactions: The Impact of Membrane Lipids.

The growing field of nanotechnology presents opportunity for applications across many sectors. Nanostructures, such as nanoparticles, hold distinct properties based on their size, shape, and chemical modifications that allow them to be utilized in both highly specific as well as broad capacities. As the classification of nanoparticles becomes more well-defined and the list of applications grows, it is imperative that their toxicity be investigated. One such cellular system that is of importance are cellular membranes (biomembranes). Membranes present one of the first points of contact for nanoparticles at the cellular level. This review will address current studies aimed at defining the biomolecular interactions of nanoparticles at the level of the cell membrane, with a specific focus of the interactions of nanoparticles with prominent lipid systems.

An Investigation of Veterinary College Websites in the US and Canada: Representations and Content of Equity, Diversity, and Inclusion.

University websites are often a first point of contact for prospective students. Portrayals of diversity on the website can influence current and future students' perceptions. Using content and statistical analysis, all 38 veterinary college websites in Canada and the US were systematically coded for representations of people in photos and content related to equity, diversity, and inclusion (EDI). In both Canada and the United States, people perceived as male or Black, Indigenous, and/or People of Color (BIPOC) were more likely to be portrayed without animals, and fewer photos with males depicted engagement in an activity compared with those depicting females. Compared with the self-identified data reported by US colleges to the American Association of Veterinary Medical Colleges, BIPOC students were under-depicted by approximately 16.3% (95% confidence interval [CI] = 11.1%-21.7%) on some college websites and over-depicted on others by approximately 23.4% (95% CI = 15.4%-31.2%). A land acknowledgment or a link for a land acknowledgment was found on only six websites (16%). These results provide evidence and support that veterinary colleges should monitor their websites for depictions of people and content related to EDI, providing the opportunity to attract a diverse student audience.

Investigation of Partial Discharge Transformation Characteristics in Polyimide (PI) Insulations under High-Frequency Electric Stress.

This research delves into the primary issue of polyimide (PI) insulation failures in high-frequency power transformers (HFPTs) by scrutinizing partial discharge development under high-frequency electrical stress. This study employs an experimental approach coupled with a plasma simulation model for a ball-sphere electrode structure. The simulation model integrates the particle transport equation, Poisson equation, and complex chemical reactions to ascertain microscopic parameters, including plasma distribution, electric field, electron density, electron temperature, surface, and space charge distribution. The effect of the voltage polarity and electrical energy on the PD process is also discussed. The contact point plays a pivotal role in triggering partial discharges and culminating in the breakdown of PI insulation. Asymmetry phenomena were found between positive and negative half-cycles by analyzing the PD data stage by stage. A significant number of PDs increased at every stage and the PD amplitude was higher during the negative cycle at the initial stage, but in later stages, the PD amplitude was found to be higher in the positive half-cycle, and scanning electron microscopy (SEM) revealed that the maximum damage occurred near the contact point junction. The simulation results show that the plasma initially accumulates the electron density near the contact point junction. Under the action of the electric field, plasma starts traveling at the PI surface outward from the contact point. Before the PD activity, all parameters have higher values in the plasma head. The microscopic parameters reveal maximum values near the contact point junction, during PD activities where significant damage takes place. These parameter distributions exhibit a decreasing trend over time as when the PD activity ends. The model's predictions are consistent with the experimental data. The paper lays the foundation for future research in polymer insulation design under high-frequency electrical stress.

Human-water interactions associated to cercarial emergence pattern and their influences on urinary schistosomiasis transmission in two endemic areas in Mali

BackgroundMali is known to be a schistosomiasis-endemic country with a limited supply of clean water. This has forced many communities to rely on open freshwater bodies for many human-water contact (HWC) activities. However, the relationship between contact with these water systems and the level of schistosome infection is currently receiving limited attention. This study assessed human-water interactions including cercarial emergence pattern and their influences on urinary schistosomiasis transmission in two communities in the Kayes district of Mali.MethodsWe carried out a parasitological study first in children in September 2021, then a cross-sectional study of quantitative observations of human-water contact activities in the population, and finally a study of snail infectivity at contact points in September 2022. The study took place in two communities, Fangouné Bamanan and Diakalèl in the Kayes region of western Mali. The chronobiological study focused on cercarial release from naturally infected snails. Released cercariae were molecularly genotyped by targeting the cox1 region, and the ITS and 18S ribosmal DNA gene (18S rDNA) regions of the DNA. Links between sociodemographic parameters, human water-contact points and hematuria were established using multivariate statistical analysis or the logistic regression model.ResultsThe main factor predisposing the 97 participants to water contact was domestic activity (62.9%). Of the 378 snails collected at 14 sampling sites, 27 (7.1%) excreted schistosome cercariae, with 15.0% (19/126) at Fangouné Bamanan and 3.3% (8/252) at Diakalel. The release of Schistosoma cercariae shows three different patterns in Fangouné Bamanan: (i) an early release peak (6:00–8:00 AM), (ii) a mid-day release peak (10:00 AM–12:00 PM) and (iii) a double peak: (6:00–8:00 AM) and (6:00–8:00 PM) cercariae release; and two release patterns in Diakalel: early release (6:00–8:00 AM) and (ii) mid-day release (12:00–2:00 PM). All cercariae released during early diurnal (6:00–8:00 AM) or nocturnal emission patterns (6:00–8:00 PM) were hybrids parasite having an cox1 S. bovis or S. curassoni associated with an ITS and 18S rDNA of S. haematobium while the cercariae released during diurnal, or mid-day patterns (8:00 AM–6:00 PM) were pure S. haematobium.ConclusionsOur study showed that domestic activity is the main source of exposure in the Kayes region. Two and three cercariae emission patterns were observed at Diakalel and Fangouné Bamanan respectively. These results suggest that the parasite adapts to the human-water contact period in order to increase its infectivity.Graphical

Analysis of Contact Point between Audio Equipment and Concha Cavity

Analysis of Contact Point between Audio Equipment and Concha Cavity

Highly-Strong and Highly-Tough Alginate Fibers with Photo-Modulating Mechanical Properties.

The good combination of high strength and high toughness is a long-standing challenge in the design of robust biomaterials. Meanwhile, robust biomaterials hardly perform fast and significant mechanical property changes under the trigger of light at room temperature. These limit the application of biomaterials in some specific areas. Here, photoresponsive alginate fibers are fabricated by using the designed azobenzene-containing surfactant as flexible contact point for cross-linking polysaccharide chains of alginate, which gain high mechanics through reinforced plastic strain and photo-modulating mechanics through isomerization of azobenzene. By transferring molecular motion into macro-scale mechanical property changes, such alginate fibers achieve reversible photo-modulations on the mechanics. Their breaking strength and toughness can be photo-modulated from 732MPa and 112MJm-3 to 299MPa and 27MJm-3, respectively, leading to record high mechanical changes among the developed smart biomaterials. With merits of good tolerance to pH and temperature, fast response to light, and good biocompatibility, the reported fibers will be suitable for working in various application scenarios as new smart biomaterials. This study provides a new design strategy for gaining highly-strong and highly-tough photoresponsive biomaterials.

Analysis of glass fiber-reinforced composite leaf springs in a light commercial vehicle

Leaf springs are designed to bear loads as well as shocks in automotive vehicles. Two leaves of glass fiber-reinforced composites (GFRCs) of various shapes sandwiched between steel plates were analyzed for application in a minitruck. Computer-aided engineering analysis was performed for five different types of GFRC material leaf springs: flat leaf, flat and parabolic leaf, both parabolic leaf, both parabolic leaf springs with aluminium alloy bushes at the eye-end and spring steel multi-leaf springs. A silencer pad was used in the parabolic leaf spring to reduce delamination and vibration at contact points of the mating leaf. The various shapes and combinations of leaves provided varying parameters, namely, the deformation, maximum equivalent strain, maximum equivalent stress and fatigue life. The CAE results showed that compared with the other combinations, the flat leaf and parabolic leaf combinations provided the maximum equivalent strain, maximum equivalent stress and fatigue life.

Aeromonas salmonicida AI-1 and AI-2 quorum sensing pathways are differentially regulated by rainbow trout mucins and during in vivo colonization

Aeromonas salmonicida is an opportunistic pathogen with relevance for aquaculture. Fish epithelia are covered by a mucus layer, composed mainly by highly glycosylated mucins, which are the first point of contact between fish and pathogens. Quorum sensing (QS), a bacterial communication mechanism through secreted autoinducer signals that governs gene expression, influences bacterial growth and virulence. The main A. salmonicida autoinducers are mediated by the luxS and asaI genes, corresponding to inter- and intraspecies communication, respectively. The aim of this study was to determine the effect of the mucins that pathogens encounter during colonization of the gill and skin on A. salmonicida QS. We found that expression of A. salmonicida asaI, but not luxS, was increased after culture at 20 °C compared to 10 °C. Rainbow trout gill and skin mucins up-regulated asaI expression 2-fold but down-regulated luxS 10-fold. The downregulation of luxS was reflected by a reduction in autoinducer-2 secretion. Mucins isolated from skin had a stronger inhibitory effect than mucins isolated from gills on both luxS expression and A1-2 secretion, consistent with a higher relative abundance of N-Acetylneuraminic acid on skin mucins than on gill mucins. Reduction of AI-2 production by mucins or luxS-deletion lead to a reduced A. salmonicida auto-aggregation. Furthermore, after colonization of the gill, luxS was down regulated whereas asaI expression was upregulated. Both in vivo and in vitro, the expression of luxS and asaI were thus differentially regulated, frequently in an inverse manner. The strong AI-2 inhibiting effect of the skin mucins is likely part of the mucin-based defense against pathogens.