Elastic Modulus Influence on the Forming Precision of Grinding Tool Bended for the Aspherical Surface Grinding

2014 ◽  
Vol 937 ◽  
pp. 391-395
Author(s):  
Chun Min Shang ◽  
Dong Mei Zhang ◽  
Jian Dong Yang
Keyword(s):  
Elastic Modulus ◽  
Tool Material ◽  
Face Shape ◽  
Shape Precision ◽  
Key Factor ◽  
The Face ◽  
Forming Precision ◽  
Grinding Tool ◽  
And Control ◽  
The Mathematical Model

Elastic modulus error is the key factor influencing to the forming precision of grinding tool bended in the aspheric processing. The mathematical model of the grinding tool bended has been established through mechanics and the mathematics method, the error formula has been inferred and the influence of elastic modulus error has been analyzed, the calculating example has been given. The result indicates had to confirm material’s elastic modulus value according to the precision request of workpiece in choosing grinding tool material and control it in the certain scope, thus guaranteed the grinding tool the forming precision, further improve the workpiece the face shape precision.

Grinding Hyperboloid Part by Bending Method

2014 ◽  
Vol 912-914 ◽  
pp. 976-980
Author(s):  
Chun Min Shang ◽  
Dong Mei Zhang ◽  
Jian Dong Yang
Keyword(s):  
Mathematical Model ◽  
High Speed ◽  
Difficult Problem ◽  
New Method ◽  
Face Shape ◽  
Shape Precision ◽  
Width Function ◽  
The Face ◽  
The Mathematical Model

In view of the machining difficult problem of hyperboloid, a new method is presented that high speed lapping hyperboloid parts using the bended lapping tool, and the principle of high speed lapping by the bending method is discussed. The mathematical model of bended lapping tool has been established using mechanics and higher mathematics, and the expression of width function of lapping tool is deduced. Analysis of the calculating example indicated that this method is possible to design the needed lapping tool. The bending experiment of lapping tool has confirmed the feasibility using this method, the biggest error of face shape was 1.0038μm, the face shape precision can satisfy the majority part request.

Lapping Aspheric Workpiece Using Bending Method

2013 ◽  
Vol 331 ◽  
pp. 595-599
Author(s):  
Chun Min Shang ◽  
Dong Mei Zhang ◽  
Jian Dong Yang
Keyword(s):  
Mathematical Model ◽  
High Speed ◽  
New Method ◽  
Aspheric Surface ◽  
Shape Precision ◽  
Tool Shape ◽  
Forming Precision ◽  
Surface Precision ◽  
The Cost ◽  
The Mathematical Model

A new method is proposed that high speed lapping aspheric surface workpiece using lapping tool by means of bending because there processing difficult, In this study, the principle of high speed lapping has been presented, the mathematical model for the lapping tool has been established, and the equidistance curve error of the lapping tool has been analyzed. The results of the experiment indicate that the forming precision of the lapping tool is high using this method, the surface precision of the workpiece reaches micron grade, furthermore, the aspheric surface workpiece can been machined using this method in lapping, and that it can meet the need of medium precision of machining the aspheric surface workpiece. The experiment result indicates that the the lapping tool shape precision is high, the lapping error of the workpiece is 0.0108mm, and lapping efficiency is high and the cost is low. This aspheric lapping method has incomparable superiority of other processing methods.

ACCESS TO AND CONTROL OVER LAND AS GENDERED: CONTEXTUALIZING WOMEN’S ACCESS AND OWNERSHIP RIGHTS OF LAND IN RURAL GHANA

2016 ◽  
Vol 45 (2) ◽  
pp. 28-48 ◽  
Author(s):  
Isaac Dery
Keyword(s):  
Thematic Analysis ◽  
Rural Women ◽  
Rural Poor ◽  
Rural Ghana ◽  
Secure Access ◽  
Key Factor ◽  
Access Rights ◽  
Ownership Rights ◽  
And Control ◽  
Relationship Of

Women’s access to and control over productive resources, including land, has increasingly been recognized in global discussions as a key factor in reducing poverty, ensuring food security and promoting gender equality. Indeed, this argument has been widely accepted by both feminists and development theorists since the 1980s. Based on qualitative research with 50 purposively selected men and women, this study explored the complexity of women’s access to and control over land within a specific relationship of contestations, negotiations, and manipulations with men. Data were analyzed using thematic analysis. While theoretically, participants showed that women’s [secure] access to and control over land has beneficial consequences to women themselves, households and the community at large, in principle, women's access and control status was premised in the traditional framework which largely deprives women, equal access and/or control over the land. The study indicates that even though land is the most revered resource and indeed, the dominant source of income for the rural poor, especially women, gender-erected discrimination and exclusion lie at the heart of many rural women in gaining access to land. This study argues that women's weak access rights and control over land continue to perpetuate the feminization of gender inequality–while men were reported to possess primary access and control over land as the heads of households, women were argued to have secondary rights due to their ‘stranger statuses’ in their husbands’ families. Overall, the degree of access to land among women was reported to be situated within two broad contexts–marriage and inheritance.

The Model for Calculating Elastic Modulus and Poisson's Ratio of Coal Body

2013 ◽  
Vol 6 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Ai Chi ◽  
Li Yuwei
Keyword(s):  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Fractured Rock ◽  
Rock Block ◽  
Poisson's Ratio ◽  
Linear Elastic ◽  
Study Results ◽  
The Face ◽  
Block Face ◽  
Coal Rock

Coal body is a type of fractured rock mass in which lots of cleat fractures developed. Its mechanical properties vary with the parametric variation of coal rock block, face cleat and butt cleat. Based on the linear elastic theory and displacement equivalent principle and simplifying the face cleat and butt cleat as multi-bank penetrating and intermittent cracks, the model was established to calculate the elastic modulus and Poisson's ratio of coal body combined with cleat. By analyzing the model, it also obtained the influence of the parameter variation of coal rock block, face cleat and butt cleat on the elastic modulus and Poisson's ratio of the coal body. Study results showed that the connectivity rate of butt cleat and the distance between face cleats had a weak influence on elastic modulus of coal body. When the inclination of face cleat was 90°, the elastic modulus of coal body reached the maximal value and it equaled to the elastic modulus of coal rock block. When the inclination of face cleat was 0°, the elastic modulus of coal body was exclusively dependent on the elastic modulus of coal rock block, the normal stiffness of face cleat and the distance between them. When the distance between butt cleats or the connectivity rate of butt cleat was fixed, the Poisson's ratio of the coal body initially increased and then decreased with increasing of the face cleat inclination.

An evaluation model of 2019-nCoV prevention effectiveness based on immigration data in China (Preprint)

2020 ◽  
Author(s):  
Qiangsheng Huang
Keyword(s):  
Prevention And Control ◽  
Time Window ◽  
Evaluation Model ◽  
Control Measures ◽  
Related Data ◽  
The Face ◽  
Prevention And Control Measures ◽  
And Control ◽  
Best Fit

BACKGROUND As of the end of February 2020, 2019-nCoV is currently well controlled in China. However, the virus is now spreading globally. OBJECTIVE This study aimed to evaluate the effectiveness of outbreak prevention and control measures in a region. METHODS A model is built for find the best fit for two sets of data (the number of daily new diagnosed, and the risk value of incoming immigration population). The parameters (offset and time window) in the model can be used as the evaluation of effectiveness of outbreak prevention and control. RESULTS Through study, it is found that the parameter offset and time window in the model can accurately reflect the prevention effectiveness. Some related data and public news confirm this result. And this method has advantages over the method using R0 in two aspects. CONCLUSIONS If the epidemic situation is well controlled, the virus is not terrible. Now the daily new diagnosed patients in most regions of China is quickly reduced to zero or close to zero. Chinese can do a good job in the face of huge epidemic pressure. Therefore, if other countries can do well in prevention and control, the epidemic in those places can also pass quickly.

scholarly journals Diagnosis and Therapeutic Management of Liver Fibrosis by microRNA

2021 ◽  
Vol 22 (15) ◽  
pp. 8139
Author(s):  
Tomoko Tadokoro ◽  
Asahiro Morishita ◽  
Tsutomu Masaki
Keyword(s):  
Liver Fibrosis ◽  
Viral Infections ◽  
Primary Biliary Cholangitis ◽  
Medical Need ◽  
Key Factor ◽  
Complications Of Cirrhosis ◽  
And Control ◽  
Functional Rnas ◽  
Remarkable Progress ◽  
Made In

Remarkable progress has been made in the treatment and control of hepatitis B and C viral infections. However, fundamental treatments for diseases in which liver fibrosis is a key factor, such as cirrhosis, alcoholic/nonalcoholic steatohepatitis, autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis, are still under development and remain an unmet medical need. To solve this problem, it is essential to elucidate the pathogenesis of liver fibrosis in detail from a molecular and cellular perspective and to develop targeted therapeutic agents based on this information. Recently, microRNAs (miRNAs), functional RNAs of 22 nucleotides, have been shown to be involved in the pathogenesis of liver fibrosis. In addition, extracellular vesicles called “exosomes” have been attracting attention, and research is being conducted to establish noninvasive and extremely sensitive biomarkers using miRNAs in exosomes. In this review, we summarize miRNAs directly involved in liver fibrosis, miRNAs associated with diseases leading to liver fibrosis, and miRNAs related to complications of cirrhosis. We will also discuss the efficacy of each miRNA as a biomarker of liver fibrosis and pathology, and its potential application as a therapeutic agent.

Effects of Face Mask Use on Objective and Subjective Measures of Thermoregulation During Exercise in the Heat

2021 ◽  
pp. 194173812110282
Author(s):  
Ayami Yoshihara ◽  
Erin E. Dierickx ◽  
Gabrielle J. Brewer ◽  
Yasuki Sekiguchi ◽  
Rebecca L. Stearns ◽  
...  
Keyword(s):  
Exercise Intensity ◽  
Thermal Sensation ◽  
Face Mask ◽  
Whole Body ◽  
Moderate Exercise ◽  
Physically Active ◽  
Time Points ◽  
The Face ◽  
And Control ◽  
Moderate Exercise Intensity

Background: While increased face mask use has helped reduce COVID-19 transmission, there have been concerns about its influence on thermoregulation during exercise in the heat, but consistent, evidence-based recommendations are lacking. Hypothesis: No physiological differences would exist during low-to-moderate exercise intensity in the heat between trials with and without face masks, but perceptual sensations could vary. Study Design: Crossover study. Level of Evidence: Level 2. Methods: Twelve physically active participants (8 male, 4 female; age = 24 ± 3 years) completed 4 face mask trials and 1 control trial (no mask) in the heat (32.3°C ± 0.04°C; 54.4% ± 0.7% relative humidity [RH]). The protocol was 60 minutes of walking and jogging between 35% and 60% of relative VO2max. Rectal temperature (Trec), heart rate (HR), temperature and humidity inside and outside of the face mask (Tmicro_in, Tmicro_out, RHmicro_in, RHmicro_out) and perceptual variables (rating of perceived exertion (RPE), thermal sensation, thirst sensation, fatigue level, and overall breathing discomfort) were monitored throughout all trials. Results: Mean Trec and HR increased at 30- and 60-minute time points compared with 0-minute time points, but no difference existed between face mask trials and control trials ( P > 0.05). Mean Tmicro_in, RHmicro_in, and humidity difference inside and outside of the face mask (ΔRHmicro) were significantly different between face mask trials ( P < 0.05). There was no significant difference in perceptual variables between face mask trials and control trials ( P > 0.05), except overall breathing discomfort ( P < 0.01). Higher RHmicro_in, RPE, and thermal sensation significantly predicted higher overall breathing discomfort ( r2 = 0.418; P < 0.01). Conclusion: Face mask use during 60 minutes of low-to-moderate exercise intensity in the heat did not significantly affect Trec or HR. Although face mask use may affect overall breathing discomfort due to the changes in the face mask microenvironment, face mask use itself did not cause an increase in whole body thermal stress. Clinical Relevance: Face mask use is feasible and safe during exercise in the heat, at low-to-moderate exercise intensities, for physically active, healthy individuals.

scholarly journals Role of attitude in nurses’ responses to requests for assisted dying

2020 ◽  
pp. 096973302096677
Author(s):  
Michael Wilson ◽  
Marie Wilson ◽  
Suzanne Edwards ◽  
Lynette Cusack ◽  
Richard Wiechula
Keyword(s):  
Online Survey ◽  
Rare Event ◽  
Control Beliefs ◽  
Assisted Dying ◽  
Cross Sectional ◽  
Assisted Death ◽  
Institutional Ethics ◽  
The Face ◽  
Generalised Linear Modelling ◽  
And Control

Background: Legal assisted dying is a rare event, but as legalisation expands, requests for it will likely increase, and the nurse most often receives the informal, initial request. Objectives: To assess the effects of attitude in interaction with normative and control beliefs on an intention to respond to a request for legal assisted dying. Ethical considerations: The study had the lead author’s institutional ethics approval, and participants were informed that participation was both anonymous and voluntary. Methodology: This was a cross-sectional correlational study of 377 Australian registered nurses who completed an online survey. Generalised linear modelling assessed the effects of independent variables against intended responses to requests for legal assisted dying. Results: Compared to nurses who did not support legal assisted dying, nurses who did had stronger beliefs in patient rights, perceived social expectations to refer the request and stronger control in that intention. Nurses who did not support legal assisted dying had stronger beliefs in ethics of duty to the patient and often held dual intentions to discuss the request with the patient but also held an intention to deflect the request to consideration of alternatives. Discussion: This study advances the international literature by developing quantified models explaining the complexity of nurses’ experiences with requests for an assisted death. Attitude was operationalised in interaction with other beliefs and was identified as the strongest influence on intentions, but significantly moderated by ethical norms. Conclusion: The complex of determinants of those intentions to respond to requests for an assisted death suggests they are not isolated from each other. Nurses might have distinct intentions, but they can also hold multiple intentions even when they prioritise one. These findings present opportunities to prepare nurses in a way that enhances moral resilience in the face of complex moral encounters.

scholarly journals Testing the face shape hypothesis in twins discordant for nonsyndromic orofacial clefting

2017 ◽  
Vol 173 (11) ◽  
pp. 2886-2892 ◽  
Author(s):  
Jasmien Roosenboom ◽  
Karlijne Indencleef ◽  
Greet Hens ◽  
Hilde Peeters ◽  
Kaare Christensen ◽  
...  
Keyword(s):  
Face Shape ◽  
Orofacial Clefting ◽  
The Face

Controller Parameters Optimization of PWM Converter Based DFIG

2014 ◽  
Vol 672-674 ◽  
pp. 1012-1015
Author(s):  
He Zhu ◽  
Da Tian Xu ◽  
Hao Ran Zhao
Keyword(s):  
Control Strategy ◽  
Simplex Algorithm ◽  
Parameters Optimization ◽  
Pwm Converter ◽  
Stator Flux ◽  
Grid Side ◽  
Rotor Side Converter ◽  
Grid Side Converter ◽  
And Control ◽  
The Mathematical Model

Based on the mathematical model of the PWM converter, control strategy of the grid-side converter directed by the grid voltage and control strategy of the rotor-side converter directed by the stator flux were established combining the vector control theory. The method using the nonlinear simplex algorithm to optimize the PI control parameters of the DFIG unit was first proposed, optimization results proved that this method had good practicality and robustness.

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