scholarly journals Asphalt layers within railway tracks’ substructure

2021 ◽  
Vol 14 (4) ◽  
pp. 612-631
Author(s):  
Jehad Qatamin ◽  
Ibrahim Amir
Keyword(s):  
High Speed ◽  
Mix Design ◽  
Railway Track ◽  
Stress And Strain ◽  
Cross Sectional ◽  
The Past ◽  
Railway Industry ◽  
Overall Performance ◽  
Design Requirements ◽  
Application Fields

For both heavy cargo Rail lines and High-Speed Lines, the railway industry continues to develop railway track design technologies. Within the past years, using an asphalt layer as a part of the railway track became so common as a support layer, it helps to reduce noise and vibration levels, reduce the thickness of the cross-sectional layers, reduce the lifetime maintenance, and many other great advantages. This paper will discuss the application of asphalt layers in railways, functionality, application fields, and types of asphalted trackbeds. Design requirements and parameters of asphalt layers, the mix design, installation process, and international experiences will be mentioned. Asphalt layers can improve the overall performance of the trackbeds and their behavior under repeated stresses of trains, the effect of asphalt layers on stress and strain ratios will be briefly discussed.

Study of a Bidirectional Proportional Electromagnet

2013 ◽  
Vol 278-280 ◽  
pp. 155-158
Author(s):  
Yue Feng Yuan ◽  
Guo Liang Tao ◽  
Hao Liu ◽  
Wei Ban
Keyword(s):  
High Speed ◽  
Magnetic Circuit ◽  
Element Model ◽  
Hall Sensor ◽  
Experimental Result ◽  
Position Sensor ◽  
Test Platform ◽  
Overall Performance ◽  
Design Requirements ◽  
Proportional Directional Valve

Aim to fulfill the design requirements of a pneumatic proportional directional valve, a novel bidirectional proportional electromagnet with integrated lineal Hall position sensor was proposed. Magnetic circuit model and finite element model were established separately. Both static force vs. armature stroke characteristic and Hall sensor output vs. armature position were tested on a newly designed test platform. The experimental result shows a good linear magnetic spring characteristic of the proportional electromagnet, which further ensures a unique spool auto reset capability for directional valves. The mass of the armature is considerably reduced, thus it will benefit the overall performance of high speed pneumatic proportional directional valves.

The on-line use of histogram data for high-speed correction and alignment of electron microscope images

1984 ◽  
Vol 42 ◽  
pp. 556-557
Author(s):  
William Krakow
Keyword(s):  
Power Spectrum ◽  
High Speed ◽  
Direct Memory Access ◽  
Digital Television ◽  
Contrast Transfer Function ◽  
The Past ◽  
High Resolution Tem ◽  
On Line ◽  
Correction Of Astigmatism ◽  
The Fourier Transform

In the past few years on-line digital television frame store devices coupled to computers have been employed to attempt to measure the microscope parameters of defocus and astigmatism. The ultimate goal of such tasks is to fully adjust the operating parameters of the microscope and obtain an optimum image for viewing in terms of its information content. The initial approach to this problem, for high resolution TEM imaging, was to obtain the power spectrum from the Fourier transform of an image, find the contrast transfer function oscillation maxima, and subsequently correct the image. This technique requires a fast computer, a direct memory access device and even an array processor to accomplish these tasks on limited size arrays in a few seconds per image. It is not clear that the power spectrum could be used for more than defocus correction since the correction of astigmatism is a formidable problem of pattern recognition.

A technique to prepare cross-sectional TEM specimens of semiconducting devices

1986 ◽  
Vol 44 ◽  
pp. 742-743
Author(s):  
A. K. Rai ◽  
P. P. Pronko
Keyword(s):  
Thin Films ◽  
Surface Region ◽  
Sample Surface ◽  
Specific Region ◽  
Cross Sectional ◽  
Thin Sections ◽  
The Past ◽  
Device Structures ◽  
Ion Implanted

Several techniques have been reported in the past to prepare cross(x)-sectional TEM specimen. These methods are applicable when the sample surface is uniform. Examples of samples having uniform surfaces are ion implanted samples, thin films deposited on substrates and epilayers grown on substrates. Once device structures are fabricated on the surfaces of appropriate materials these surfaces will no longer remain uniform. For samples with uniform surfaces it does not matter which part of the surface region remains in the thin sections of the x-sectional TEM specimen since it is similar everywhere. However, in order to study a specific region of a device employing x-sectional TEM, one has to make sure that the desired region is thinned. In the present work a simple way to obtain thin sections of desired device region is described.

An atomic-resolution microscope study of Al contracts on GaAs

1986 ◽  
Vol 44 ◽  
pp. 726-727
Author(s):  
Z. Liliental-Weber ◽  
C. Nelson ◽  
R. Ludeke ◽  
R. Gronsky ◽  
J. Washburn
Keyword(s):  
High Speed ◽  
Schottky Contacts ◽  
Detailed Knowledge ◽  
The Past ◽  
Semiconductor Interfaces ◽  
Deposited Metal ◽  
Microwave Applications ◽  
Free Interfaces ◽  
Potential Use

The properties of metal/semiconductor interfaces have received considerable attention over the past few years, and the Al/GaAs system is of special interest because of its potential use in high-speed logic integrated optics, and microwave applications. For such materials a detailed knowledge of the geometric and electronic structure of the interface is fundamental to an understanding of the electrical properties of the contact. It is well known that the properties of Schottky contacts are established within a few atomic layers of the deposited metal. Therefore surface contamination can play a significant role. A method for fabricating contamination-free interfaces is absolutely necessary for reproducible properties, and molecularbeam epitaxy (MBE) offers such advantages for in-situ metal deposition under UHV conditions

Suicidal Ideation Among Medical Students in Dammam, Saudi Arabia

Crisis ◽  
2020 ◽  
pp. 1-6
Author(s):  
Mohammed Madadin ◽  
Ritesh G. Menezes ◽  
Maha A. Alassaf ◽  
Abdulaziz M. Almulhim ◽  
Mahdi S. Abumadini ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Medical Students ◽  
Suicidal Ideation ◽  
General Health Questionnaire ◽  
Cross Sectional Study ◽  
Eastern Province ◽  
Cross Sectional ◽  
The Past ◽  
Depression Subscale ◽  
History Of

Abstract. Background: Medical students are at high risk of suicidal ideation. Aim: We aimed to obtain information on suicidal ideation among medical students in Dammam located in the Eastern Province of Saudi Arabia. Method: This cross-sectional study was conducted at the College of Medicine affiliated with Imam Abdulrahman Bin Faisal University in the Eastern Province of Saudi Arabia. Suicidal ideation in the past 12 months was assessed based on responses to four questions in the depression subscale of the General Health Questionnaire 28 (GHQ-28). In addition, data were collected to examine the association of suicidal ideation with various factors. Results: We found that 1 in 3 medical students in the study had suicidal ideation in the past 12 months, while around 40% had lifetime suicidal ideation. Suicidal ideation was associated with feelings of parental neglect, history of physical abuse, and dissatisfaction with academic performance. Limitations: The cross-sectional nature of this study limits its ability to determine causality regarding suicidal ideation. Conclusion: These rates are considerably high when compared with rates from studies in other countries around the world. This study provides a reference in the field of suicidology for this region of Saudi Arabia.

Contributory Factors for Obesity in Elderly: Review of the Literature

2019 ◽  
Vol 15 (3) ◽  
Author(s):  
Nur Raihan Ismail ◽  
Noor Aman Hamid
Keyword(s):  
English Language ◽  
The Elderly ◽  
Dietary Factors ◽  
Health Concern ◽  
Cross Sectional ◽  
Contributory Factors ◽  
The Past ◽  
Prevalence Of Obesity ◽  
Program Intervention ◽  
Future Education

Introduction: The prevalence of obesity has been rising, adding to morbidity and mortality. As the proportion of elderly aged 60 years and above grows, so too the prevalence of obesity among this population. Obesity in the elderly is a rapidly growing public health concern as it contributes to significant changes in the health of older people. Objective: This review aims to assess the contributory factors for obesity in the elderly over the past decade. Methods: A literature search was conducted. The search was restricted to articles written in the English language published from 2008 to 2018. Qualitative studies were excluded. Results: A total of 19 full articles were retrieved, of which 18 cross-sectional and one cohort were included. The contributory factors were divided into three components: (a) socio demographic characteristics, (b) medical history and dietary factors and (c) environmental factors. Conclusions: This review informs an emerging knowledge regarding contributory factors for obesity and has implications for future education and program intervention in fighting obesity in the elderly.

Sampling, Preservation and Counting of Samples II: Zooplankton

2017 ◽  
Author(s):  
Peter H. Wiebe ◽  
Ann Bucklin ◽  
Mark Benfield
Keyword(s):  
Genetic Analysis ◽  
High Speed ◽  
Morphological Analysis ◽  
Taxonomic Composition ◽  
Sampling Techniques ◽  
Sample Analysis ◽  
Sample Preservation ◽  
The Past ◽  
Plankton Collection

This chapter reviews traditional and new zooplankton sampling techniques, sample preservation, and sample analysis, and provides the sources where in-depth discussion of these topics is addressed. The net systems that have been developed over the past 100+ years, many of which are still in use today, can be categorized into eight groups: non-opening/closing nets, simple opening/closing nets, high-speed samplers, neuston samplers, planktobenthos plankton nets, closing cod-end samplers, multiple net systems, and moored plankton collection systems. Methods of sample preservation include preservation for sample enumeration and taxonomic morphological analysis, and preservation of samples for genetic analysis. Methods of analysis of zooplankton samples include determination of biomass, taxonomic composition, and size by traditional methods; and genetic analysis of zooplankton samples.

scholarly journals Hepatitis and tuberculosis testing are much less common than HIV testing among adults in Kisumu, Kenya: results from a cross-sectional assessment

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Joshua Tunnage ◽  
Adam Yates ◽  
Chiaka Nwoga ◽  
Valentine Sing’oei ◽  
John Owuoth ◽  
...  
Keyword(s):  
Secondary Education ◽  
Viral Hepatitis ◽  
Hiv Testing ◽  
Spatial Location ◽  
Tuberculosis Screening ◽  
Cross Sectional ◽  
The Past ◽  
Prior Testing ◽  
Testing Uptake ◽  
One Year

Abstract Background Kenya has a high burden of HIV, viral hepatitis, and tuberculosis. Screening is necessary for early diagnosis and treatment, which reduces morbidity and mortality across all three illnesses. We evaluated testing uptake for HIV, viral hepatitis, and tuberculosis in Kisumu, Kenya. Methods Cross-sectional data from adults aged 18–35 years who enrolled in a prospective HIV incidence cohort study from February 2017 to May 2018 were analyzed. A questionnaire was administered to each participant at screening for study eligibility to collect behavioral characteristics and to assess prior testing practices. Among participants without a history of previously-diagnosed HIV, multivariable robust Poisson regression was used to estimate prevalence ratios (PRs) and 95% confidence intervals (CIs) for factors potentially associated with HIV testing in the 12 months prior to enrollment. A hierarchical model was used to test for differential access to testing due to spatial location. Results Of 671 participants, 52 (7.7%) were living with HIV, 308 (45.9%) were female, and the median age was 24 (interquartile range 21–28) years. Among 651 (97.0%) who had ever been tested for HIV, 400 (61.2%) reported HIV testing in the past 6 months, 129 (19.7%) in the past 6–12 months, and 125 (19.1%) more than one year prior to enrollment. Any prior testing for viral hepatitis was reported by 8 (1.2%) participants and for tuberculosis by 51 (7.6%). In unadjusted models, HIV testing in the past year was more common among females (PR 1.08 [95% CI 1.01, 1.17]) and participants with secondary education or higher (PR 1.10 [95% CI 1.02, 1.19]). In the multivariable model, only secondary education or higher was associated with recent HIV testing (adjusted PR 1.10 [95% CI 1.02, 1.20]). Hierarchical models showed no geographic differences in HIV testing across Kisumu subcounties. Conclusions Prior HIV testing was common among study participants and most had been tested within the past year but testing for tuberculosis and viral hepatitis was far less common. HIV testing gaps exist for males and those with lower levels of education. HIV testing infrastructure could be leveraged to increase access to testing for other endemic infectious diseases.

scholarly journals Ten-year trends of hypertension treatment and control rate in Korea

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kwang-il Kim ◽  
Eunjeong Ji ◽  
Jung-yeon Choi ◽  
Sun-wook Kim ◽  
Soyeon Ahn ◽  
...  
Keyword(s):  
Age Groups ◽  
Favorable Effect ◽  
Age Group ◽  
Hypertension Treatment ◽  
Treatment Rate ◽  
Cross Sectional ◽  
The Past ◽  
Nationally Representative ◽  
Multistage Sampling ◽  
And Control

AbstractWe analyzed the Korean National Health and Nutrition Examination Survey (KNHANES) database to determine the trends of hypertension treatment and control rate in Korea over the past 10 years. In addition, we tried to investigate the effect of chronic medical conditions on hypertension management. We investigated the hypertension prevalence, awareness, treatment, and control rate from 2008 to 2017. KNHANES, which uses a stratified multistage sampling design, is a cross-sectional, nationally representative survey conducted by the Korean government. A total of 59,282 adults (≥ 20 years) were included, which was representative of the total population of around 40 million Koreans per year. The mean age was 50.7 ± 16.4 years and 42.6% were male. The prevalence of hypertension, hypercholesterolemia, diabetes mellitus, and obesity significantly increased over the 10 years. During this period, the hypertension treatment and control rate significantly improved. Hypertension treatment rate was significantly lower in the younger age group compared to the older age group, but the control rate among the treated patients was not significantly different between age groups. The treatment and control rates of hypertension were higher in patients with multimorbidity, which implies that it has a favorable effect on the treatment and control of hypertension. Hypertension treatment and control rate have improved over the past 10 years. The higher treatment and control rate in patients with multimorbidity suggest that the more aggressive surveillance might be associated with the improvement of hypertension treatment and control rate in Korea.

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