Theory Modeling Research Articles

Structural equation modeling and Fuzzy set theory: Advancing risk assessment in oil and gas construction projects

This research seeks to evaluate the critical risks associated with Oil and Gas Construction Projects (O&GCPs) in terms of their level of significance and quantifiable effects on Project Performance (PP) by surveying O&GCPs experts in the USA. A multiphase research methodology was adopted, including Systematic Literature Review (SLR) to identify the key O&GCPs risks; semi-structured interviews to identify PP indicators and establish hypotheses on the effect of O&GCPs risks on PP; surveys to assess the perceived agreement of O&GCPs experts regarding the effects of O&GCPs risks on PP, and to rank the probability and impact of the identified O&GCPs risks; Structural Equation Model (SEM) to quantitatively assess the effects of O&GCPs risks on PP; Fuzzy Set Theory (FST) to assess the level of significance of O&GCPs risks; and interviews to verify the developed assessment models and their outputs. The SLR analysis identified 35 articles on O&GCP risks from 2013 to 2023, revealing 51 risk factors in eight categories based on their sources. The SEM analysis indicated that the oil and gas safety risks category had the strongest direct impact on PP. Furthermore, the FST analysis revealed that non-compliance with PPE emerged as the most significant risk factor across all categories of O&GCP risks. This study enhances knowledge and practice by aiding researchers and practitioners in understanding how key O&GCP risks impact PP. This improved understanding is expected to facilitate the formulation of effective mitigation strategies during the early stages of the projects.

Driving Factors of Shading Adjustment Behavior Based on Social Cognitive Theory and Structural Equation Modeling

Research on occupant behavior is a crucial aspect of building energy-saving research. Among them, the shading adjustment behavior in buildings, which occurs frequently during building usage, significantly impacts building energy consumption. Due to the randomness of shading adjustment behavior and the complexity of its motivations, interdisciplinary research is required in this field. In order to better analyze the driving factors of shading adjustment behavior and thus provide a reference for promoting building energy-saving technologies and strategies, this paper employs novel methods for research. We establish a structural equation model based on social cognitive theory, then design a questionnaire and collect data. We utilize structural equation modeling to examine the interrelationships between different dimensions. We ultimately determine the connections between different driving factors of shading adjustment behavior. The results show that whether in the behavior of activating or deactivating shading, environmental factors have a positive correlation with personal factors, and both environmental and personal factors significantly influence shading adjustment behavior. Furthermore, within environmental factors, social environmental factors also significantly affect shading adjustment behavior. Lastly, comparing the behaviors of activating and deactivating shading, the impacts of light and thermal environmental factors on shading adjustment behavior show certain differences.

Estimating velocity distribution and flood discharge at river bridges using entropy theory – insights from computational fluid dynamics flow fields

Abstract. Estimating the flow velocity and discharge in rivers is of particular interest for monitoring, modeling, and research purposes. Instruments for measuring water level and surface velocity are generally mounted on bridge decks, and this poses a challenge because the bridge structure, with piers and abutments, can perturb the flow field. The current research aims to investigate the applicability of entropy theory to estimate the velocity distribution and the discharge in the vicinity of river bridges. For this purpose, a computational fluid dynamics (CFD) model is used to obtain three-dimensional flow fields along a stretch of the Paglia River (central Italy), where a historical multi-arch bridge strongly affects flood flows. The input data for the entropy model include the cross-sectional bathymetry and the surface velocity provided by the numerical simulations. A total of 12 samples, including three different flow conditions at four cross-sections, one upstream and three downstream of the bridge, are considered. It is found that the entropy model can be reliably applied upstream of the bridge, also when forced with a single (i.e., the maximum) value of the surface velocity, with errors on total discharge below 13 % in the considered case. By contrast, downstream of the bridge, the wakes generated by the bridge piers strongly affect the velocity distribution, both in the spanwise and in the vertical directions and for very long distances. Here, notwithstanding the complex and multimodal spanwise distribution of flow velocity, the entropy model estimates the discharge with error lower than 8 % if forced with the river-wide distribution of the surface velocity. The present study has important implications for the optimal positioning of sensors and suggests the potential of using CFD modeling and entropy theory jointly to foster greater knowledge of river systems.

Deciphering the cytotoxic and antioxidant potential of 3,5-disubstituted isoxazole-linked benzimidazolone derivatives

A series of new isoxazole derivatives containing a benzimidazolone has been synthesized by cycloaddition reaction using various nitrile oxides. In all cases, these cycloadditions are completely chemo and regioselective. The structures of the new cycloadducts were characterized by 1H, 13C NMR spectroscopy, HRMS and confirmed in one case by a single crystal structure determination. The isoxazole compounds were evaluated for in vitro antioxidant activity using the DPPH and ABTS methods. As a result, compound 5a showed good antioxidant activity. The results of the acute toxicity study of the heterocycles studied by the oral route showed no deaths and no clinical signs of toxicity. Additionally, the Hirshfeld surface analysis and the molecular electrostatic potential using density functional theory (DFT) modeling at the B3LYP/6–31G(d,p) level. Hirshfeld surface analysis (dnorm surface and 2D-fingerprint plots) revealed the nature of intermolecular contacts. H⋯H interactions make the most significant contribution to crystal packing. The optimized structural parameters obtained through DFT calculations closely matched those determined via X-ray analysis, demonstrating strong agreement between theoretical predictions and experimental observations.

Density functional theory guide for copolymerization mechanism between allyl radical with radicalophile: photo-driven radical mediated [3 + 2] cyclization.

The challenge of activating inert allyl monomers for polymerization has persisted, prompting our proposal of the photo-driven radical mediated [3 + 2] cyclization reaction (PRMC). This innovative approach significantly expedites the homopolymerization of multi-allyl monomers, enabling the synthesis of embolic microspheres for hepatocellular carcinoma interventions. PRMC involves allyl monomers to form allylic radicals and then radicals participating in a cycloaddition reaction with unsaturated olefins as radicalophiles to form cyclopentane-based radical products. While extensively studied in the theoretical and experimental homopolymerization, PRMC's application in copolymerization remains unexplored. To address this knowledge gap, we explored the elementary reaction, selecting allyl methyl ether radicals (AMER) and α,β-unsaturated ketones as radicalophiles for copolymerization investigations by density functional theory (DFT) analysis. We quantified energy differences between ground and excited states of reactants, elucidated frontier molecular orbitals, and assessed thermodynamic data for copolymerization feasibility. We also evaluated the electronic properties of reactants, predicting the reactivity of radicalophiles and the interactions of intermolecular reactions. Additionally, we applied transition state theory and interaction/deformation models and conducted a local orbital analysis to comprehensively study excess electron distribution and gyration radius of cyclic radical product. Our findings offer vital insights into PRMC's potential in copolymerization. This research provides a robust theoretical foundation for practical application, enhancing the polymerization field. Based on density functional theory (DFT), the calculations were performed at the M06-2X/6-311 + + G(d,p) level in/by Gaussian 16 package. Subsequently, our analytical results apply time-dependent density-functional theory (TD-DFT) and solvent modeling (SMD). Single-point energy calculations determine the driving force behind the radicals' reaction with radicalophiles. Furthermore, we assessed the electrostatic potential (ESP) of the reactants. The results of the calculations were visualized by the Multiwfn 3.6 and VMD 1.9 programs.

Fuzzy Logic Theory and Spatiotemporal Modeling of the Fungus Phakopsora pachyrhizi Based on Differential Equations

Brazil has been one of the largest soybean producers in recent years. The soybean is a legume commonly found in family meals. Among the diseases affecting the grains, Asian soybean rust is one of the most concerning. The fungus causing the disease is spread by the wind, making it difficult to control. Although it has been researched since its first records, not much data are available regarding the macro propagation behavior of spores. Therefore, this research aimed to model its dispersion based on a partial differential equation, the diffusion–advection equation, used by researchers to model the behavior of any pollutant. The terms of this equation were developed from real data, processed by fuzzy logic, and the simulation results were compared with disease records throughout a harvest. By using this approach to model the spatiotemporal dynamics of this fungus, it was possible to simulate its spread satisfactorily. Additionally, its results were used as input variables for a fuzzy system that estimates the susceptibility of a given location to disease development.

Do Psychological Ownership and Communicative Presence Matter? Examining How User-Generated Content in E-Commerce Live Streaming Influences Consumers' Purchase Intention.

E-commerce live streaming has become a lucrative global industry. As the main carrier to convey information in live broadcasting, user-generated content (UGC)-and especially bullet screens-are crucial in influencing users' purchase intentions. However, the influence of bullet screens' multidimensional information characteristics on consumers' decision-making processes requires further exploration. Additionally, most existing studies start with the short-term effects of live product realization, and must address how to enhance customers' psychological ownership using new means of live streaming marketing to obtain long-term sustainable brand-building effects. This study introduces psychological ownership and the communicative presence as mediating variables based on the theory of elaboration likelihood modeling to explore the mechanism of the influence of UGC's multidimensional features on viewers' purchase intentions in live e-commerce broadcasting rooms. We collected 404 valid online questionnaires and tested our hypotheses using structural equation modeling. These findings indicate that UGC emotions, quality, and their interaction significantly and positively affect purchase intentions. Moreover, psychological ownership and the communicative presence mediate UGC's effect on purchase intentions. These results provide a new perspective for understanding consumer behavior in live e-commerce to improve marketing effectiveness of e-commerce live streaming platforms.

Systematic Elastostatic Stiffness Model of Over-Constrained Parallel Manipulators Without Additional Constraint Equations

The establishment of an elastostatic stiffness model for over constrained parallel manipulators (PMs), particularly those with over constrained subclosed loops, poses a challenge while ensuring numerical stability. This study addresses this issue by proposing a systematic elastostatic stiffness model based on matrix structural analysis (MSA) and independent displacement coordinates (IDCs) extraction techniques. To begin, the closed-loop PM is transformed into an open-loop PM by eliminating constraints. A subassembly element is then introduced, which considers the flexibility of both rods and joints. This approach helps circumvent the numerical instability typically encountered with traditional constraint equations. The IDCs and analytical constraint equations of nodes constrained by various joints are summarized in the appendix, utilizing multipoint constraint theory and singularity analysis, all unified within a single coordinate frame. Subsequently, the open-loop mechanism is efficiently closed by referencing the constraint equations presented in the appendix, alongside its elastostatic model. The proposed method proves to be both modeling and computationally efficient due to the comprehensive summary of the constraint equations in the Appendix, eliminating the need for additional equations. An example utilizing an over constrained subclosed loops demonstrate the application of the proposed method. In conclusion, the model proposed in this study enriches the theory of elastostatic stiffness modeling of PMs and provides an effective solution for stiffness modeling challenges they present.

Systematic Literature Review (SLR): Explorations flood systems theory and appropriate modeling

Urban flood risk assessment conducts a comprehensive evaluation of hazard formative factors, hazard formative environment, hazard-affected bodies, and capabilities for disaster prevention and reduction in order to obtain an accurate assessment of flood risk levels. The current study aimed to conduct a systematic review of the existing literature on engagement outcomes, focusing on high-quality studies Each step of the SLR method and their results are explained in detail in the following subsections using SLR performed. Using the SLR method can help answer the objectives of this research in the form of: What type of modeling to overcome flooding This research uses the SLR method which aims to recognize, review, and evaluate Using bibliometric analysis.To achieve the goal of SLR, the variables of interest are organized based on the general characteristics of the article and the specific parameters used general information about the article includes year of publication, type of analysis (quantitative, qualitative, cartographic or mixed), type and scale of research, and the country or region where the research was conducted. The model consists of three components, including rainfall runoff, river channels, and flooding The flow in the channel was generated with a 1D diffusion wave model, and the outflow on the slope was generated with a 2D model.This article showed the basic steps that need to be followed to conduct SLR This method generates topic-specific existing knowledge, trends, and observed gaps and helps to draw relevant conclusions for policy makers and the scientific community. and the appropriate modeling is Press RRI refers to 2D grid-based fluid dynamics and is a model that combines a hydrological model and a flood model.

Systematic Literature Review (SLR): Explorations flood systems theory and appropriate modeling

Urban flood risk assessment conducts a comprehensive evaluation of hazard formative factors, hazard formative environment, hazard-affected bodies, and capabilities for disaster prevention and reduction in order to obtain an accurate assessment of flood risk levels. The current study aimed to conduct a systematic review of the existing literature on engagement outcomes, focusing on high-quality studies Each step of the SLR method and their results are explained in detail in the following subsections using SLR performed. Using the SLR method can help answer the objectives of this research in the form of: What type of modeling to overcome flooding This research uses the SLR method which aims to recognize, review, and evaluate Using bibliometric analysis.To achieve the goal of SLR, the variables of interest are organized based on the general characteristics of the article and the specific parameters used general information about the article includes year of publication, type of analysis (quantitative, qualitative, cartographic or mixed), type and scale of research, and the country or region where the research was conducted. The model consists of three components, including rainfall runoff, river channels, and flooding The flow in the channel was generated with a 1D diffusion wave model, and the outflow on the slope was generated with a 2D model.This article showed the basic steps that need to be followed to conduct SLR This method generates topic-specific existing knowledge, trends, and observed gaps and helps to draw relevant conclusions for policy makers and the scientific community. and the appropriate modeling is Press RRI refers to 2D grid-based fluid dynamics and is a model that combines a hydrological model and a flood model.

Exploring the Kinetics of Oxygen Reduction Reaction in Relation to Pitting Corrosion Resistance in Fe-Cr Alloys

Pitting corrosion, a major concern in materials science and engineering, threatens critical metallic structures and components. Its implications reach across daily life and industries such as energy, transportation, and infrastructure, potentially causing environmental harm, economic losses, and even loss of life. This complex process is influenced by factors including material composition, local environment, and mechanical stresses.1 Once initiated, pit propagation rates are largely dependent on the magnitude of the supporting cathodic current available from the oxygen reduction reaction (ORR) occurring on the external passive film.2 In Fe-Cr alloys, the ORR occurs on this film, undergoing a mixed diffusion and kinetic-controlled process. The number of electrons involved and the corrosion rate are determined by the thermodynamically stable state of the passive film.This research studies the ORR kinetics on FeCr alloys fabricated by arc-melting, using both computational and experimental methods. The rotating disc electrode technique was employed across various Fe:Cr alloys in alkaline and neutral electrolytes. The Koutecky-Levich analysis showed a dominant four-electron ORR pathway in all tested Fe-Cr alloys, with the ORR significantly inhibited by higher proportions of Cr2O3 in the film, suggesting a correlation with high chromium content. Experimental ORR overpotentials, when combined with theoretical potential-pH (Pourbaix) diagrams, helped discern the likely characteristics of the passive films on the alloys. It was deduced that the catalytic properties of potential passive films increased in the order Cr2O3 < Fe3O4 < Fe2O3 < FeCr2O4. These findings, excellently aligned with density functional theory (DFT) modelling, underscore the role of increased chromium levels in slowing pitting progression by suppressing the ORR.In summary, this research offers distinctive insights into the correlation between the kinetics of the ORR and the resistance to localized corrosion in Fe-Cr alloys, which enhances our understanding of the underlying mechanisms of pitting corrosion. Keywords FeCr alloy, pitting corrosion, ORR, rotating disc electrode, DFT Reference [1] B. Zhang, J. Wang, B. Wu, X. W. Guo, Y. J. Wang, D. Chen, Y. C. Zhang, K. Du, E. E. Oguzie, and X. L. Ma, Nat. Commun. (2018) 9, 2559.[2] G. T. Burstein, P. C. Pistorius, and S. P. Mattin, Corros. Sci. (1993) 35, 57.

Preparation of T8 and double-decker silsesquioxane-based Janus-type molecules: molecular modeling and DFT insights

We present a methodology for the synthesis of inorganic-organic Janus-type molecules based on mono-T8 and difunctionalized double-decker silsesquioxanes (DDSQs) via hydrosilylation reactions, achieving exceptionally high yields and selectivities. The synthesized compounds were extensively characterized using various spectroscopic techniques, and their sizes and spatial arrangements were predicted through molecular modelling and density functional theory (DFT) calculations. Quantum chemical calculations were employed to examine the interactions among four molecules of the synthesized compounds. These computational results allowed us to determine the propensity for molecular aggregation, identify the functional groups involved in these interactions, and understand the changes in interatomic distances during aggregation. Understanding the aggregation behaviour of silsesquioxane molecules is crucial for tailoring their properties for specific applications, such as nanocomposites, surface coatings, drug delivery systems, and catalysts. Through a combination of experimental and computational approaches, this study provides valuable insights into the design and optimization of silsesquioxane-based Janus-type molecules for enhanced performance across various fields.

Study on the window spill fire plume trajectory of over-ventilated intermediate-scale compartment fires

The fire plume behavior of over-ventilated compartment fire is believed to be related with the façade fire. When the fire plume is reattached to the façade wall, the combustible materials over building wall are potential to be ignited soon. To investigate the window spill fire plume trajectory of over-ventilated intermediate-scale compartment fires, a modeling of fire plume trajectory is set up by using the energy conservation equation and spread theory. The temperature history of over-ventilated compartment fire is conducted by using a 1.35 m (L) × 1.35 m (H) × 1.35 m (W) compartment with window opening aspect varied from 1.12 to 4.44 and HRR differed from 200 kW to 1000 kW. The temperature of fire plume is recorded by the thermocouple mesh and the IR camera. It shows that the modelling theory could be used to predict the shape of fire plume. It agrees well with experimental result. The heat release rate of compartment fire is found to impact little influence on the shape of fire plume regarding a fixed opening dimension. It could provide a reasonable method for fire plume trajectory prediction of the intermediate-scale enclosure fire under an over-ventilated condition.

Mechanism of the impacts of older adults social participation on their health.

Against the background of population aging challenges in China, focusing on health, security, and social participation as core elements of positive aging, this study aims to formulate strategies for promoting the health of the older adults and reveal the pathways and trends of social participation in promoting health. The study analyzed 1,015 randomly selected older adults individuals living at home in Beijing using household survey questionnaires. Drawing on group dynamics theory and structural equation modeling, the study proposed hypotheses regarding the relationships between social participation, group cohesion, and health status. First, the triangular path model of social participation, group cohesion, and health status among the older adults was established. The direct path coefficient of social participation on health status was 0.15, that of social participation on group cohesion was 0.56, and that of group cohesion on health status was 0.32. The indirect path coefficient of social participation on health status through group cohesion was calculated at 0.56 × 0.32 = 0.18. Second, of the older adults age groups-younger, middle, and older-social participation's direct path effects on health status were present only in the older age group. Social participation's indirect path effects on health status through group cohesion were relatively high in all three groups, with a slight increase in the older age group. First, just the older adults participation in social activities serves as a benign stimulus to physical and mental health. Additionally, group cohesion formed through interaction with others during social activities encourages self-improvement behaviors, indirectly promoting health. In fact, indirect pathways of health promotion through group cohesion are stronger than direct pathways, highlighting the importance of group cohesion during social participation. Second, participation in activities alone can provide only sufficient benign stimuli for the older adults aged 80 and above, with the direct path effect of social participation on health beginning to appear only with increasing age. With age, selectivity of interaction with others decreases, and dependence increases; social participation's indirect path effect on health through group cohesion continues to grow slightly.

Restoring Psychiatric Mental Health APRN Roles: A Report of Innovations in Workforce Development Design Supported by Salutogenic Solutions and an Enduring Educational Frame, Part One.

The change from a clinical nurse specialist to nurse practitioner model has significantly affected graduate education and practice because of emphasis on the dominant biomedical prescriber role, marginalizing the nurse-psychotherapy and consultation-liaison roles fundamental to quality psychiatric advanced practice nursing practice. We report on a four-year Workforce Development Project supported by an academic-practice partnership to restore formation and skill building of the marginalized roles. Part One focuses on program design, the curriculum for nine specialty courses, and the teaching and learning community approach that promotes engagement, faculty commitment, and preceptor recruitment and retention; the creative faculty staffing model is described. The educational frame described includes highlights of teaching/learning strategies drawn from the history of professional formation curriculum rooted in salutogenesis and belonging science, existentialism, solution-focused therapy, modeling and role modeling theory, and Peplau's Interpersonal Relations . There is significant interest and commitment to learning the nurse-psychotherapist and consultation-liaison roles.

Studying the influence of correction codes on coherent reception of M-PSK signals in the presence of noise and harmonic interference

Objectives. Signals with multiple phase shift keying (M-PSK) exhibiting good spectral and energy characteristics are successfully used in many information transmission systems. These include satellite communication systems, GPS, GLONASS, DVB/DVB-S2, and a set of IEEE 802.11 wireless communication standards. In radio communication channels, the useful signal is affected by various interferences in addition to noise. One of these is harmonic interference. As a result, high intensity harmonic interference practically destroys the reception of M-PSK signals. One of the important requirements for the quality of data transmission is the system error tolerance. There are different ways of improving the quality of information transmission. One of these is the use of corrective encoding technology. The aim of the paper is to assess the noise immunity of a coherent demodulator of M-PSK signals using Hamming codes (7,4) and (15,11), and convolutional encoding with Viterbi decoding algorithm (7,5) when receiving M-PSK signals under noise and harmonic interference in the communication channel.Methods. The methods of statistical radio engineering, optimal signal reception theory and computer simulation modeling were used.Results. Experimental dependencies of the bit error rate on the signal-to-noise ratio and on the intensity of harmonic interference of coherent reception of M-PSK signals in a channel with noise and harmonic interference were obtained using computer simulation modeling. This was done without using correction codes and with Hamming code (7.4) and (15.11) and convolutional encoding with Viterbi decoding algorithm (7,5).Conclusions. It is shown that the application of the correction codes effectively corrects errors in the presence of noise and harmonic interference with lower intensity. The correction is ineffective in the presence of high intensity interference. These results can provide important guidance in designing the reliable and energy efficient system.

Сценарное моделирование протестного потенциала на основе событийной идентификации динамики факторов

In this study, we present a scenario-based approach to investigate the protest potential in society using mathematical tools from graph theory and simulation modeling. The research objective. The research aims to construct a cognitive map that reflects key factors, such as population deprivation levels, overall well-being, social fears, trust in authority, social expectations, and stability of social structures. Materials and methods. The model of functional oriented graphs, which in turn is a development of the classical cognitive model, is used as a metamathematical apparatus in the study. In the software implementation, the method of linear regression data analysis was used to calculate e-scenarios for the behavior of vertices. Results. We report the results of a scenario analysis of the developed model, obtaining forecasted scenarios of the dynamics of society’s protest potential under various conditions and influences. At the core of this research is the examination of a complex system’s possible response to external destructive impacts, and we propose a set of measures to counteract these influences on societal dynamics. The scenario methodology combines graph theory for representing complex relationships between key factors and simulation modeling for predicting potential developmental scenarios. Conducting this study required modifying the traditional mathematical apparatus of cognitive modeling. We developed methods and algorithms for scenario-event identification of the model’s significant factors’ behavior and utilizing the results of such identification when forming complex functional relationships in the scenario model. In generating scenarios, the range of events is significantly expanded compared to traditional cognitive modeling approaches, which could have been overlooked but may be crucial for situational analysis. Conclusion. The scenario modeling technology presented in the work is implemented in the appropriate software and analytical complex, the purpose of which is to automate the processes of scenario research of socio-economic and political systems.

Fundamental Properties of Adjoint Model and Adjoint Sensitivity Under Fully Nonlinear Hydrostatic Internal Gravity Waves

AbstractAdjoint sensitivity modeling plays an important role in inverse problems, including four‐dimensional variational data assimilation or state estimation, by providing the sensitivity of the objective (or cost) function to the model input data. Although data assimilation has become common in regional ocean modeling, and the model resolution has become high enough to resolve internal tides, it remains unclear whether physically sensible and stable adjoint sensitivity modeling is feasible in the presence of internal waves. As a first step to tackle this problem, this study investigates fundamental properties of the adjoint of a time‐dependent circulation model, and the resulting sensitivity under internal waves. The theoretical and numerical results, based on simple‐internal‐wave theory and MITgcm modeling, show that stable adjoint sensitivity modeling is feasible under fully nonlinear (but stable) hydrostatic internal waves. However, it requires a careful choice of the objective function to obtain sensitivity which has the same propagation properties as (real‐world) internal waves, because the definition primarily controls the directionality and vertical‐mode content of internal‐wave signals in the adjoint model. Also, it should be noted that the internal‐wave signals lack indirect sensitivity through the dependence of the wave‐propagation speed on the model's prognostic variables. An important implication of the results is that the standard form of the objective function, which has been used in data assimilation studies for quasi‐geostrophic flows and barotropic tides, could be problematic for internal tides.

The Use of a Spanish-Translated PrEP Stigma Scale among the Latino Sample of the UNITE Cohort Study.

Pre-Exposure Prophylaxis (PrEP) related stigma is linked to inadequate PrEP uptake, yet there are no validated scales to test this association among Spanish-speaking LSMM. The current study examined if the Spanish-translated PrEP Stigma Scale (PSS) was psychometrically appropriate for implementing in Spanish language dominant Latino/e/x Sexual Minority Men (SMM). Recruitment was conducted using geosocial networking applications, social media sites, and e-mail blasts (N=3,049). First, we utilized Item Response Theory (IRT) modeling to evaluate the reliability of the PSS items and the latent construct across both language groups (nEnglish = 2844 and nSpanish = 205). Subsequently, we applied the PSS scale in a theoretical application by examining its association with key steps in the PrEP uptake cascade (i.e., perceived PrEP candidacy, PrEP willingness, PrEP intentions, and having spoken to provider about PrEP) stratified by language. Results of the IRT analyses provided evidence that the translated version of the PSS was appropriate for use among this sample. Further, among English respondents, PrEP stigma was negatively associated with perceived PrEP candidacy (B=-0.30, p=<.001), PrEP willingness (B=-0.46, p=<.001), and PrEP intentions (B=-0.23, p=.003). PrEP stigma, among Spanish respondents, was not significantly associated with any of the PrEP cascade steps. This study demonstrated that the PSS scale performs adequately for both English and Spanish-speaking Latino SMM. However, researchers and health professionals alike should pay close attention to the nuanced effects in U.S. based English and Spanish language samples as PrEP stigma may impact the PrEP cascade for one language sample and not the other.

Research on failure simulation of the feeding system considering transmission gear wear

Abstract The feeding process of the feeding system in the power transmission chain was a high-speed, high impact, non-stationary process, and easy to detect functional faults, aimed at the problem, based on nonlinear multi-body dynamics and Dubowsky contact modeling theory, a gear transmission modeling method including backlash was proposed. A dynamic simulation model of the feeding system injected with gear wear fault was established, and the system dynamic performance under different wear levels was analyzed. The research results show that due to the wear of the gear teeth, the contact force between the teeth increased by about 70%. When the wear of a single tooth pair increased to 0.2mm, there would be jamming faults caused by delayed chain throwing. The research results provided support for the optimization and improvement of the feeding system.