Design and Analysis for Hypoid Gears with Ease-Off Flank Modification

An approach of ease-off flank modification for hypoid gears was proposed to improve the meshing performance of automobile drive axle. Firstly, a conjugate pinion matching with gear globally was developed based on gear meshing theory. Secondly, a modified pinion was represented by a sum of two vector functions determining the conjugate pinion and the normal ease-off deviations expressed by both predesigned transmission error function and tooth profile modification curves to change the initial contact clearance of the tooth. Thirdly, the best ease-off deviations were determined by optimizing the minimum amplitude of loaded transmission error (ALTE) based on tooth contact analysis (TCA) and loaded tooth contact analysis (LTCA). Finally, the results show that effective contact ratios (εe) are established by clearances both teeth space and of contact elliptical, and greatly affect ALTE. The εe is a variable value with increasing loads for the tooth with modification. ALTE decreases with increasing εe. After εe reaches the maximum, ALTE increases with increasing loads. The mismatch of the best ease-off tooth is minimal, which contributes to effective reduction in ALTE, thus significantly improving drive performance.

A plague epidemic disease optimizing approach

In order to solve some optimization problems with multi-local optimal solutions, a plague infectious disease optimization (PIDO) algorithm is proposed by the dynamic model of plague infectious disease with pulse vaccination and time delay. In this algorithm, it is assumed that there are several villagers living in a village, each villager is characterized by some characteristics. The plague virus is prevalent in the village, and the villagers contract the infectious disease through effective contact with sick rats. The plague virus attacks is the few characteristics of the human body. Under the action of the plague virus, the growth status of each villager will be randomly transformed among 4 states of susceptibility, exposure, morbidity and recovery, thus a random search is achieved for the global optimal solution. The physical strength degree of villagers is described by the human health index (HHI). The higher the villager’s HHI index, the stronger the physique and the higher the surviving likelihood. 9 operators (S_S, S_E, E_E, E_I, E_R, I_I, I_R, R_R, R_S) are designed in the PIDO algorithm, and each operator only deals with the 1/1000∼1/100 of the total number of variables each time. The case study results show that PIDO algorithm has the characteristics of fast search speed and global convergence, and it is suitable for solving global optimization problems with higher dimensions.

Calibrating COVID-19 susceptible-exposed-infected-removed models with time-varying effectivecontact rates

We describe the population-based susceptible-exposed-infected-removed (SEIR) model developed by the Irish Epidemiological Modelling Advisory Group (IEMAG), which advises the Irish government on COVID-19 responses. The model assumes a time-varying effective contact rate (equivalently, a time-varying reproduction number) to model the effect of non-pharmaceutical interventions. A crucial technical challenge in applying such models is their accurate calibration to observed data, e.g. to the daily number of confirmed new cases, as the history of the disease strongly affects predictions of future scenarios. We demonstrate an approach based on inversion of the SEIR equations in conjunction with statistical modelling and spline-fitting of the data to produce a robust methodology for calibration of a wide class of models of this type. This article is part of the theme issue ‘Data science approaches to infectious disease surveillance’.

Examining the relationships between social identities of British Asian transgender /gender non-conforming and well-being.

Objective: The present study aimed to explore the roles of social identity (British Asian / TGNC)against mental health problems (depression) and well-being.Methods: This study is a mixed methods pilot study. British Asian TGNC adults were our targeted subjects. An online anonymous survey was opened for four weeks and shared by some LGBTQ+ communities in the U.K. We recruited three participants, which did not meet planned sample size requirements.Results: Due to the lack of participants, we cannot reject our support any of our hypothesis. Based on the qualitative analysis, we inferred some possible findings: (1) double stigmatized individuals reported great experiences of discrimination related to their stigmatized social identity; (2) people who hold double stigmatized identity may show asymmetric identification; (3) affirmation of multiple identities could provide resilience and then foster mental health and well-beings.Conclusion: Our study demonstrated the difficulties in recruitment double minority group of people. The reasons of the failure in recruitment could be (1) double stigmatized identity may lead to concealment (2) COVID-19 causes problems in direct contact. Implications on recruitment issues within double stigmatized identities are extensively discussed, with discussions against how these areas relate to effective contact and engagement with specialist service for British Asian TGNC individuals and communities. Having a theoretical and practical understanding of these issues may address future recruitment difficulties

188. Visualizing the Impact of a Wedding Leading to COVID-19 Outbreaks in Healthcare Settings, Washington State, July – August 2020

Background Large social gatherings during the COVID-19 pandemic have been linked to extensive community transmission. Healthcare workers (HCW) that engage in these social gatherings pose a risk to the vulnerable patients they serve. Public Health—Seattle & King County identified a COVID-19 outbreak associated with a wedding in July 2020 when the 14-day incidence rate was 105 cases per 100,000 residents. HCW who attended the wedding were subsequently linked to 45 outbreaks in healthcare settings across three counties in the next month. Methods COVID-19 case interview data was used to identify HCW cases who reported the wedding as their exposure event. The Washington Disease Reporting System (WDRS), the state database in which COVID-19 cases and epi-linkages are tracked, was queried to identify healthcare outbreaks linked to the HCW wedding-attendee cases and the HCW that they infected. NodeXL was used to visualize the resulting chains of wedding-associated healthcare transmission using a Harel-Koren Fast Multiscale layout where the network visualization’s directed arrows represent putative links and direction of transmission. Numbers of associated settings, cases, and deaths were calculated. Results Seven HCW wedding attendees were linked to outbreaks in healthcare facilities that they worked at while infectious; HCWs linked to as many as six subsequent healthcare outbreaks. In total, the wedding was connected to 45 healthcare facilities: adult family homes (N=1), hospitals (N=1), supported living agencies (N=7) and associated group homes (N=38), assisted living (N=1), home health services (N=1), behavioral health (N=2), and rehab centers (N=1). Across the settings, 277 cases were identified, including 15 deaths. Conclusion A series of COVID-19 healthcare outbreaks was traced back to a wedding. Cases worked in multiple homes, agencies, and other healthcare settings which likely facilitated rapid and wide transmission; the structure of these healthcare settings often do not facilitate a single job providing enough hours and income to support an individual. In terms of public health learnings, addressing these outbreaks require effective contact tracing, multijurisdictional coordination, and for supported living, interventions need to be applied across households sharing staff. Disclosures All Authors: No reported disclosures

Study of Green Seaweed Biochar for Lead Adsorption from Aqueous Solution

The current work used a batch study to investigate the efficiency of Ulva lactuca carbon for lead adsorption from aqueous solution. For the optimization study, the effects of several parameters such as pH, Adsorbent dosage, effective contact time, and initial concentration on lead removal were also considered. pH 3 was observed to be the most beneficial. The Langmuir isotherm, which represents mono-layer adsorption, yielded a maximum lead absorption of 3.49 mg/g. SEM was used to examine surface adsorption behavior, and FTIR was used to detect probable functional groups involved in the bio-adsorption experiment. This study shows that biochar made from the marine algae Ulva lactuca is effective for waste water treatment.

In-situ hydrogen wettability characterisation for Underground Hydrogen Storage

Hydrogen storage in subsurface aquifers or depleted gas reservoirs represents a viable seasonal and/or long-term energy storage solution. However, currently, there is a scarcity of subsurface petrophysical data for the hydrogen system, limiting modelling work and industrial rollout. In this work, we address the knowledge gap by determining the wettability and Interfacial Tension (IFT) of the hydrogen-brine-quartz system using a multi-modal, in-situ approach. We utilise the captive bubble, pendant drop and in-situ 3D micro-Computed Tomography (CT) methods to rigorously characterise a hydrogen-brine-Bentheimer rock system, applicable to high quartz sandstone storage systems generally. The captive bubble method determined the effective contact angle ranged between 29°-39° for pressures 6.89-20.68MPa and salinities from distilled water to 5000ppm NaCl brine. In-situ methods confirmed the water-wet system with the mean of the macroscopic and apparent contact angle distributions being 39.77° and 59.75° respectively. Further confirmation of the water-wet system was provided by curvature analysis of fluid clusters. The pendant drop method determined that IFT decreased with increasing pressure in distilled water from 72.45 mN/m at 6.89MPa to 69.43 mN/m at 20.68MPa. No correlation was found between IFT and salinity for the 1000ppm and 5000ppm brines. Our fundamental studies provide insights into the physics of hydrogen wetting in multiphase environments of subsurface reservoirs. With this, we can make informed estimates of relative permeability and capillary pressure for the hydrogen-brine system to model the storage capacity and withdrawal rate of hydrogen in target reservoirs.

A mathematical analysis of the dynamics of chikungunya virus transmission

In this paper, a deterministic model for the dynamics of chikungunya virus transmission is formulated and analyzed. It is shown that the model has a disease free equilibrium (DFE) and by using the basic reprodution number (R0) local stability of DFE is proved when R0 < 1. Also, the global stability of DFE is investigated by Lyapunov function and LaSalle Invariance Principle. We show that there exists a unique endemic equilibrium (EE) of the model which is locally asymptotically stable whenever R0 > 1 and establish the global stability of the EE when R0 > 1, by using Lyapunov function and LaSalle Invariance Principle for a special case. Numerical simulations and sensitivity analysis show that the destruction of breeding sites and reduction of average life spans of vector would be effective prevention to control the outbreak. Controlling of effective contact rates and reducing transmissions probabilities may reduce the disease prevalence. GANITJ. Bangladesh Math. Soc.41.1 (2021) 41-61

Time-varying mesh stiffness calculation for gear pairs with misalignment errors in multiple degrees of freedom based on an analytical method

Misalignment errors (MEs) in multiple degrees of freedom (multi-DOFs) at the mesh position will lead to a change in the time-varying mesh stiffness (TVMS) and then affect the dynamic behaviour of gear pairs. Therefore, a new, more rapid, three-dimensional analytical model for TVMS calculation for gear pairs with three rotational and three translational MEs is established in this paper, and a new solution method based on potential energy theory is presented. In addition, the correctness of the new model is verified by the finite element method (FEM). Moreover, the effective contact line, uneven distribution of mesh force on the contact line, and mesh position change are taken into account. Finally, the TVMS under different ME conditions is calculated with the new analytical model. The results showed that the different MEs have dissimilar effects on the TVMS, and the relationship between the ME and TVMS is nonlinear. In addition, the region of single-pair and double-pair teeth in contact would also change with ME.