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2D Carbon Fiber Reinforced High Density Polyethylene Multi-Layered Laminated Composite Panels:Structural,Mechanical,Thermal,and Morphological Profile

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Journal of Materials Science & Technology 2016年第10期32卷 1077-1082页

作者： Shahzad Maqsood Khan Nafisa Gull Muhammad Azeem Munawar Atif Islam Saba Zia Muhammad Shafiq Aneela Sabir Syed Muhammad Awais Muhammad Arif butt Muhammad Taqi zahid butt Tahir Jamil Department of Polymer Engineering and Technology University of the PunjabLahore 54590Pakistan King Edward Medical University Lahore 54590Pakistan College of Engineering and Emerging Technologies University of the PunjabLahore 54590Pakistan

Carbon fiber reinforced high density polyethylene multi-layered laminated composite panels（HDPE/CF MLCP） with excellent in-plane properties along transverse direction have been formulated. Composite architectures with carbon fiber（CF） designed in 2D layout in conventional composites can alleviate their properties in thickness direction, but all attempts so far developed have achieved restrained success. Here,we have exposed an approach to the high strength composite challenge, without altering the 2D stack design on the basis of concept of fiber reinforced laminated composites that would provide enhanced mechanical and thermal properties along transverse direction. CF sheets allowed the buckling of adjoining plies in 2D MLCP. We fabricated 2D MLCP by stacking the alternative CF and HDPE layers under different loading conditions, which resulted in high strength composites. These plies of CF and HDPE served as unit cells for MLCP, with CF offering much-needed fracture toughness and hardness to these *** 2D HDPE/CF MLCP, we demonstrated noteworthy improvement in physical and chemical interaction between CF and HDPE, in-plane fracture strain, flexural strength（30.684 MPa）, bending modulus（7436.254 MPa）, thermal stability（40.94%）, and surface morphology, upon increasing the CF layers up to twenty, enabling these composites truly for high temperature and high strength applications.

关键词： Multi-layered composite panels Mechanical properties Thermal stability

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A Systematic Review of Observational Studies, Demonstrating Smoking among School Going Adolescents

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Open Journal of Epidemiology 2019年第2期9卷 173-189页

作者： Shafquat Rozi Gillian Lancaster Sadia Mahmud zahid Ahmad butt Talat Roome Nida zahid Department of Community Health Sciences Aga Khan University Karachi Pakistan Department of Mathematics and Statistics Lancaster University Lancashire United Kingdom Visiting Faculty Department of Medicine Consultancy Department of Pediatrics & Child Health Aga Khan University Karachi Pakistan School of Population and Public Health University of British Columbia Vancouver Canada Department of Pathology Dow University of Health Sciences Karachi Pakistan Department of Surgery Aga Khan University Karachi Pakistan

Objective: To characterize the methods of design and analysis currently adopted in survey research of school-based observational studies for smoking, and to identify the common pitfalls made by researchers. Methods: The systematic review was conducted in 2009 and consisted of observational studies in school settings published between January 2005 and January 2009. Smoking status was the main outcome of interest. Following Cochrane style, five steps were followed: setting selection criteria for studies and conducting a literature search;review of abstracts;review of complete articles;data extraction and quality assessment of included studies;and, finally, synthesis of studies. Results: Of the 292 abstracts retrieved, 45 (15.4%) articles were selected for the final review. Inconsistencies were found in the definition of smoking behaviour which impeded generalisability. Individual-level factors had importance, but environmental level factors were also important in studying the aetiology of smoking. Results showed that studies inappropriately reported sample size estimation and important confounding factors. Hierarchical linear modelling, random effects modelling and structural equation modelling were employed in comparatively few studies. Conclusions: There were concerns regarding data analysis of complex surveys. Fifty five percent of reviewed studies ignored environmental effects which may have produced unreliable inferences. Multi-level analysis assisted in understanding school-level effects.

关键词： Adolescent Smoking Observational Studies School-Based Survey

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Towards safe injection practices for prevention of hepatitis C transmission in South Asia: Challenges and progress

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World Journal of Gastroenterology 2016年第25期22卷 5837-5852页

作者： Naveed Zafar Janjua zahid Ahmad butt Bushra Mahmood Arshad Altaf Clinical Prevention Services British Columbia Centre for Disease Control School of Population and Public Health University of British Columbia Vancouver Service Delivery and Safety World Health Organization

AIM: To summarize the available information about injection use and its determinants in the South Asian region. METHODS: We searched published and unpublished literature on injection safety in South Asia published during 1995-2016 using the keywords "injection" "unsafe injection" and "immunization injection" and combined these with each of the countries and/or their respective states or provinces in South Asia. We used a standardized questionnaire to abstract the following data from the articles: the annual number of injections per capita, the proportion of injections administered with a reused syringe or needle, the distribution of injections with respect to prescribers and providers and determinants of injection use. RESULTS: Although information is very limited for certain countries(i.e., Bhutan, Maldives and Sri Lanka), healthcare injection use is very common across South Asia, with cross-country rates ranging from 2.4 to 13.6 injections/person/year. Furthermore, recent studies show that 5% to 50% of these injections are provided with reused syringes, thus creating potential to transmission of blood-borne pathogens. Qualified and unqualified practitioners, especially in the private sector, are the major drivers behind injection use, but patients also prefer injections, especially among the rural, poor or uneducated in certain countries. According to available data, Pakistan and India have recently taken steps towards achieving safe injection. Potential interventions include the introduction of reuse prevention devices, and patient-, community- and patient/community and provider-centered interventionsto change population and practitioner behavior. CONCLUSION: Injection use is common in South Asian countries. Multilevel interventions aiming at patients, providers and the healthcare system are needed to reduce injection use and reuse.

关键词： Unsafe injections Hepatitis C Hepatitis B South Asia Prescription practices

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Differing profiles of people diagnosed with acute and chronic hepatitis B virus infection in British Columbia,Canada

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World Journal of Gastroenterology 2018年第11期24卷 1216-1227页

作者： Mawuena Binka zahid a butt Stanley Wong Mei Chong Jane A Buxton Nuria Chapinal Amanda Yu Maria Alvarez Maryam Darvishian Jason Wong Gina McGowan Mikhail Torban Mark Gilbert Mark Tyndall Mel Krajden Naveed Z Janjua British Columbia Centre for Disease Control Vancouver BC V5Z4R4Canada School of Population and Public Health University of British ColumbiaVancouver BC V6T1Z3Canada Division of Population and Public Health Ministry of HealthVictoria BC V8W9P1Canada Department of Pathology and Laboratory Medicine University of British ColumbiaVancouver BC V6T1Z2Canada

AIM To describe the characteristics of people diagnosed with acute and chronic hepatitis B virus(HBV) infection in British Columbia(BC).METHODS We used data from the BC Hepatitis Testers Cohort(BCHTC),which includes all individuals tested for hepatitis C virus(HCV) or human immunodeficiency virus(HIV) or those diagnosed with HBV or active tuberculosis in BC since *** data were integrated with prescription drug,medical visit,hospitalization and mortality *** cases were classified as acute or chronic according to provincial *** compared characteristics of individuals by HBV infection group(acute,chronic and negative).Factors associated with acute or chronic HBV infection were assessed with multinomial logistic regression models in comparison to the HBV negative ***46498 of the 1058056 eligible BC-HTC participants were diagnosed with HBV infection.4.3% of HBV positive individuals were diagnosed with acute HBV infections while 95.7% had chronic *** alcohol use,injection drug use,and HIV or HCV co-infection were more common among individuals diagnosed with acute HBV compared to those with chronic infections and HBV negative *** multivariable multinomial logistic regression models,we observed significant associations between acute or chronic HBV diagnosis and being male,age at HBV diagnosis or birth cohort,South and East Asian ethnicity,HCV or HIV infection,and injection drug *** odds of acute HBV decreased with increasing age among people who inject drugs,while the opposite was true for chronic *** with acute HBV were predominantly White(78%) while those with chronic HBV were mostly East Asian(60%).Relative to Whites,East Asians had 12 times greater odds of being diagnosed with chronic HBV *** odds increased with increasing socioeconomic *** Differences in the profiles of people diagnosed with acute and chronic HBV infection necessitate differentiated screening,preven

关键词： Hepatitis B virus Ethnicity Drug use Acute hepatitis B BC Hepatitis Testers Cohort North America

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Smooth Sliding Mode Control for PEM Fuel Cell System

Smooth Sliding Mode Control for PEM Fuel Cell System

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第24届中国控制与决策会议

作者： S. Saqib H. Rizvi A. I. Bhatti Qudrat Khan Qadeer Ahmad Asad Hameed zahid butt CASPR Dept.of Electronics Engineering Mohammad Ali Jinnah University

A smooth sliding mode control （SSMC） is applied to tackle the problem of PEM fuel cell system output voltage stabilization problems along with controlling oxygen excess ratio. The oxygen excess ratio is controlled in the inner control loop using PID while the regulation of output voltage is being treated in the outer loop through smooth sliding mode control. The control is applied on the validated nonlinear model of the PEM fuel cell system. The simulation results show that the scheme with SSM control provides same performance as compared to higher order sliding mode control （Super twisting Algorithm） in output voltage stabilization and also in minimizing the fuel consumption.

关键词： Smooth Sliding Mode Control PEM Fuel Cell System

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