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Particuology 2019年第5期17卷 22-29页

作者： M. hafizur rahman Lius Daniel Ujash Shah Xiaotao Bi John R. Grace C.Jim Lim Fluidization Research Centre Department of Chemical & Biological Engineering University of British Columbia 2360 East Mall Vancouver British Columbia V6T1Z3 Canada

Operation of a dual fluidized bed, consisting of a riser as combustor and bubbling bed as gasifier, for synthesis gas production from a solid fuel requires determination of the solids circulation rate and char transfer rate. The performance relies on supplying sufficient heat from the combustor to the gasifier by circulation of solids between these two reactors. The flow rate of char is required to track the heat generated in the combustor, which supports endothermic reactions in the gasifier. Direct measurement of these two critical parameters is difficult, with the number of reported techniques capable of working at high temperatures extremely small. An indirect method was developed, using mass and energy balances over the entire system and individual reactors, to estimate the solids circulation rate and char transfer rate. There was general agreement between heat losses estimated from energy-balance calculations and from direct measurement of the outer reactor surface temperature. Under typical gasification conditions, the solids circulation fluxes were estimated to be 45.2 and 55.6 kg/(m^2 s) in two independent tests, which were in good agreement with values obtained using a thermal tracer;char transfer rates were calculated to be 1.2 and 0.6 kg/h, which were in reasonable agreement with average biomass feed rates. This method can be applied to dual gasification systems at any temperature or flow rate.

关键词： Solids circulation rate Char transfer rate Pilot-plant gasifier Dual fluidized bed Mass and energy balance

Antiglycation,antioxidant and toxicological potential of polyphenol extracts of alligator pepper,ginger and nutmeg from Nigeria

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Asian Pacific Journal of Tropical Biomedicine 2012年第9期2卷 727-732页

作者： Kazeem MI Akanji MA hafizur rahman M Choudhary MI Department of Biochemistry University of llorin Department of Biochemistry Lagos State University Dr.Panjwani Center for Molecular Medicine and Drug Research International Center for Chemical and Biological SciencesUniversity of Karachi

Objective:To evaluate the antioxidant and antiglycation potential of polyphenols from three spices;alligator pepper,ginger and ***:Polyphenol extracts of these spices were subjected to brine-shrimp lethality assay,phyloloxicily test,DPPH and superoxide anion radical scavenging as well as BSA-glucose antiglycation ***:Results obtained showed that polyphenol extract of ginger has the highest anlioxidant potential with IC_(50)0.075 and 0.070 mg/*** DPPH and superoxide anion radical scavenging assay while alligator pepper displayed highest antiglycation activity with IC_(50)0.125 mg/***,nutmeg extract exhibited weakest cytotoxic and phytotoxic potential with LD_(50)4359.70 and 1490μg/mL ***:It can be concluded that the polyphenol extracts of alligator pepper,ginger and nutmeg displayed good antioxidant as well as antiglycation potential and are,safe for consumption.

关键词： Glycation Hyperglycemia Polyphenols Spices Free radicals Antioxidants

Study on the Physical and Mechanical Properties of Al-Powder Reinforced Bioactive Glass: Ceramic Composite Material

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Advances in Materials Physics and Chemistry 2022年第2期12卷 19-32页

作者： Muhammad hafizur rahman Khan Sazzad Hossain Mohammad Maksudur rahman Department of Physics International University of Business Agriculture and Technology Dhaka Bangladesh Department of Physics Jahangirnagar University Savar Dhaka Bangladesh

Glass-ceramic samples, having composition of SiO2-35, CaO-45, Na2O-10 and P2O5-10 in weight ratio were prepared through sintering route. Glass powder was reinforced by Al powder. The strength of glass-ceramic composite was found to be temperature dependent, and it varies with the addition of Al powder. Flexural strength increases with the increase of powder addition and sintering temperature, however, decreases with the increase of sintering time. There is an optimum temperature (>1100℃) above which flexural strength of all samples decreases. Bulk density changes to a higher value as the addition of Al-powder increases up to 3% by weight above which density decreases slowly. On the other hand, apparent porosity and water absorption decrease with the increase of percentage of Al powder added. Porosity and water absorption also showed a dependent characteristic on sintering time and sintering temperature.

关键词： Biomaterials Glass Ceramics Aluminum Powder Composite Material

Nutritional Analysis and Determination of Heavy Metal Content of Some Spices from the Northern Region, Bangladesh

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Food and Nutrition Sciences 2022年第6期13卷 558-567页

作者： Md. Zahidul Islam Shaikh Shahinur rahman Apurba Kumar Das Md. Kamruzzaman Md. hafizur rahman Natore Agro Limited Natore Bangladesh Department of Applied Nutrition and Food Technology Islamic University Kushtia Bangladesh Khulna Medical College Hospital Khulna Bangladesh

Spices are generally consumed because of their medicinal properties, taste, and add flavor to food. Objectives: To determine the nutrient contents and heavy metals of five commonly consumed spices, namely turmeric (Curcuma longa), bay leaf (Laurus nobilis), red chili (Capsicum annuum), coriander (Coriander sativum), and black cumin (Nigella sativa) were collected from the local market of Northern zone, Bangladesh and were analyzed. Methods: Nutrient composition was assessed by proximate analysis, trace and heavy metals by atomic absorption spectrophotometry while the indophenol method was used to determine vitamin C. Result: The results revealed that spices are good sources of carbohydrate, fiber, and fat. The highest levels of carbohydrates, dietary fiber, protein, and fat were observed in turmeric (71.1%), black cumin (40.0%), red chili (16.77%), and coriander (17.8%) respectively. Vitamin C was present in trace amounts ranging from 0.04 to 0.1 mg/100g, except black cumin (35.0 mg/100g). Essential trace minerals like sodium, potassium, calcium, magnesium, and iron were significantly present in black cumin and bay leaf. Most of the heavy metal levels in the spices were appreciable amounts i.e. much lesser than the statutory safe limit approved by WHO and FAO for some of the samples. Conclusion: The current study concluded that the investigated spices are nutritionally rich, and heavy metal levels in the examined samples are safe for human consumption.

关键词： Spices Heavy Metals Nutrients Nutritional Composition Atomic Absorption Spectrophotometer

Adaptive Routing Algorithms and Implementation for TESH Network

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Communications and Network 2013年第1期5卷 34-49页

作者： Yasuyuki Miura Masahiro Kaneko M. M. hafizur rahman Shigeyoshi Watanabe ACS Co. Ltd. Tokyo Japan International Islamic University Malaysia (IIUM) Kuala Lumpur Malaysia Shonan Institute of Technology Kanagawa Japan

The Tori-connected mESH (TESH) Network is a k-ary n-cube networks of multiple basic modules, in which the basic modules are 2D-mesh networks that are hierarchically interconnected for higher level k-ary n-cube networks. Many adaptive routing algorithms for k-ary n-cube networks have already been proposed. Thus, those algorithms can also be applied to TESH network. We have proposed three adaptive routing algorithms—channel-selection, link-selection, and dynamic dimension reversal—for the efficient use of network resources of a TESH network to improve dynamic communication performance. In this paper, we implement these routers using VHDL and evaluate the hardware cost and delay for the proposed routing algorithms and compare it with the dimension order routing. The delay and hardware cost of the proposed adaptive routing algorithms are almost equal to that and slightly higher than that of dimension order routing, respectively. Also we evaluate the communication performance with hardware implementation. It is found that the communication performance of a TESH network using these adaptive algorithms is better than when the dimension-order routing algorithm is used.

关键词： TESH Network Adaptive Routing Algorithm Hardware Cost Router Delay Communication Performance

Seasonal Variation of Potential Source Locations of Atmospheric Particulates over the Indo-Gangetic Plain of India

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Open Journal of Air Pollution 2020年第1期9卷 1-10页

作者： Mohammad hafizur rahman V. P. Sharma S. Kundu A. Datta Center for Environmental Studies Earth Sceinces & Climate Change Division The Energy and Resources Institute New Delhi India

Ambient particulate matter (PM2.5 and PM10) concentrations were measured during two different seasons (summer and winter) at three different locations of Gurugram which is located in the Indo-Gangetic plain of India. The ambient concentrations of both PM2.5 and PM10 were higher during winter season (PM2.5: 261 μg·m-3;PM10: 440 μg·m-3) when compared to summer period (PM2.5: 114 μg·m-3;PM10: 202 μg·m-3). Potential Source Contribution Function (PSCF) analysis suggests significant seasonal variation in potential contributing locations of ambient PM2.5 over the study area. The PSCF analysis suggests that cross country transport of PM2.5 from Pakistan and Afghanistan significantly attributed to higher concentrations of PM2.5 at the study locations;whereas, PM2.5 emitted from locations in the south-western direction of the study sites attributed to the ambient PM2.5 concentrations at the study site during summer seasons. Further study is required to measure percentage contribution from different sectors and locations to the ambient particulate concentrations at the study site to develop sector specific mitigation plan.

关键词： Ambient Particulate Matter Indo-Gangetic Plain Region PSCF Analysis

Economic costs of hospitalized diarrheal disease in Bangladesh:a societal perspective

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Global Health Research and Policy 2018年第1期3卷 377-388页

作者： Abdur Razzaque Sarker Marufa Sultana Rashidul Alam Mahumud Nausad Ali Tanvir M Huda M.Salim uzzaman Sabbir Haider hafizur rahman Ziaul Islam Jahangir A.M.Khan Robert Van Der Meer Alec Morton International Centre for Diarrhoeal Disease Research Bangladesh(icddrb)DhakaBangladesh University of Strathclyde GlasgowUK Sydney School of Public Health Sydney Medical SchoolThe University of SydneySydneyAustralia Institute of Epidemiology Disease Control and ResearchDhakaBangladesh Health Economics Unit Ministry of Health and Family WelfareDhakaBangladesh Liverpool School of Tropical Medicine LiverpoolUK

Background:Diarrheal diseases are a major threat to human health and still represent a leading cause of morbidity and mortality *** the burden of the diarrheal diseases is much lower in developed countries,it is a significant public health problem in low and middle-income countries like *** diarrhea is preventable and managed with low-cost interventions,it is still the leading cause of morbidity according to the patient who sought care from public hospitals in Bangladesh indicating that significant resources are consumed in treating those *** aim of the study is to capture the inpatients and outpatient treatment cost of diarrheal disease and to measure the cost burden and coping mechanisms associated with diarrheal ***:This study was conducted in six randomly selected district hospitals from six divisions(larger administrative units)in *** study was performed from the societal perspective which means all types of costs were identified,measured and valued no matter who incurred *** analysis was estimated using the guideline proposed by the World Health Organization for estimating the economic burden of diarrheal *** study adopted quantitative techniques to collect the household and hospital level data including structured and semi-structured questionnaires,observation checklists,analysis of hospital database,telephone interviews and compilation of service ***:The average total societal cost of illness per episode was BDT 5274.02(US$67.18)whereas the average inpatient and outpatient costs were BDT 8675.09(US$110.51)and BDT 1853.96(US$23.62)*** cost burden was significantly highest for poorest households,21.45%of household income,compared to 4.21%of the richest ***:Diarrheal diseases continue to be an overwhelming problem in *** economic impact of any public health interventions(either preventive or promotive)that can reduce the prevalence

关键词： Bangladesh Catastrophic expenditure Cost-of-illness Diarrhea Out-of-pocket payment Public hospitals

Surgical Outcomes of Spinal Tumour: Experiences of 48 Cases at Referral Neurosurgery Hospital in Bangladesh

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Open Journal of Modern Neurosurgery 2016年第3期6卷 98-104页

作者： Shamsuzzaman Mondle Joynul Islam hafizur Rashid A. T. M. Ashadullah Fazle Elahi Bayazidur rahman Kazi Hafiz Uddin Abdullah Yusuf Department of Neurosurgery Shaheed Taj Uddin Ahmed Medical College Gazipur Bangladesh Department of Clinical Neurosurgery National Institute of Neurosciences & Hospital Dhaka Bangladesh Department of Microbiology National Institute of Neurosciences & Hospital Dhaka Bangladesh

Background: Spinal tumour has a great morbidity. Objective: The purpose of the present study was to see the outcome of the spinal tumour surgery. Methodology: Patients with spinal tumor have undergone surgery in neurospine unit of National Institute of Neurosciences and Hospital, Dhaka, Bangladesh from May 2013 to March 2015 for a period of 23(twenty three) months. Plain X-ray and MRI were done in all cases. All patients have undergone surgery through posterior midline approach. They were evaluated preoperatively and at discharge usually on 10th postoperative day after stitch removal and advised to attend in follow up clinic after 2 months of surgery. Result: 50 - 59 years age group was observed as most vulnerable for tumor occurrence (23 cases, 47.9%). The male female ratio was 1:1.3. The highest number (28 cases, 58.4%) of tumor was observed in thoracic region but the highest variety was schwannoma (33 cases, 68.7%). Initial presentation of patients was pain (32 cases, 66.7%), motor disturbances (9 cases 18.7%), sensory disturbances (5 cases 10.4%) and sphincter disturbances (2 cases 4.2%). Symptomatic improvement was in 44 (91.7%) patients whereas improvement in Frankel Scale was observed in 10 (20.8%) patients during follow up. 4 (8.4%) patients deteriorated and there was no death in this series. Conclusion: In conclusion, majority of the spinal tumour patients are presented with schwannoma with good symptomatic improvement.

关键词： Spinal Tumour Schwannoma Spinal Surgery