检索结果-南通市图书馆

Time-Dependent Flow with Convective Heat Transfer through a Curved Square Duct with Large Pressure Gradient

Open Journal of Fluid Dynamics 2015年第3期5卷 238-255页

作者： Rabindra Nath Mondal Md. Nurul Amin Helal poly rani shaha Nayan Kumar Poddar Department of Mathematics Jagannath University Dhaka Bangladesh Additional Director (Education) Training Directorate BGB Head Quarter Pilkhana Dhaka Bangladesh

A numerical study is presented for the fully developed two-dimensional laminar flow of viscous incompressible fluid through a curved square duct for the constant curvature δ = 0.1. In this paper, a spectral-based computational algorithm is employed as the principal tool for the simulations, while a Chebyshev polynomial and collocation method as secondary tools. Numerical calculations are carried out over a wide range of the pressure gradient parameter, the Dean number, 100 ≤ Dn ≤ 3000 for the Grashof number, Gr, ranging from 100 to 2000. The outer wall of the duct is treated heated while the inner wall cooled, the top and bottom walls being adiabatic. The main concern of the present study is to find out the unsteady flow behavior i.e. whether the unsteady flow is steady-state, periodic, multi-periodic or chaotic, if Dn or Gr is increased. It is found that the unsteady flow is periodic for Dn = 1000 at Gr = 100 and 500 and at Dn = 2000, Gr = 2000 but steady-state otherwise. It is also found that for large values of Dn, for example Dn = 3000, the unsteady flow undergoes in the scenario “periodic→chaotic→periodic”, if Gr is increased. Typical contours of secondary flow patterns and temperature profiles are also obtained, and it is found that the unsteady flow consists of single-, two-, three- and four-vortex solutions. The present study also shows that there is a strong interaction between the heating-induced buoyancy force and the centrifugal force in a curved square passage that stimulates fluid mixing and consequently enhance heat transfer in the fluid.

关键词： Curved Square Duct Secondary Flow Time-Evolution Periodic Solution Chaos

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nurses’ Experiences in Service Provision a COVID-19 Dedicated Tertiary Public Hospital

引用

Open Journal of Nursing 2022年第11期12卷 725-737页

作者： Suniti Halder poly rani Kundu Auparna Biswas Senior Staff Nurse Dhaka Medical College Hospital Dhaka Bangladesh Senior Staff Nurse Sadar Hospital Narail Narail Bangladesh Senior Staff Nurse National Institute of Cancer Research and Hospital Dhaka Bangladesh

Objectives: To assess the nurses’ experiences in service provision a COVID-19 dedicated tertiary public hospital. Materials and Methods: This descriptive cross-sectional study was conducted in one tertiary level public hospital namely Dhaka Medical College Hospital (DMCH), Dhaka, Bangladesh from January to December 2021. Data were collected through face-to-face interview using a structured questionnaire containing demographic details and experiences faced by the nurses in service provision during COVID-19. Data was analysed by using SPSS (Statistical Package for Social Science) software version 23. Results: The findings revealed that the mean age of the respondents was 32.35 ± 7.248 years, the minimum age was 23 years and maximum age was 58 years. About half of the respondents 52.1% were in 21 - 30 years. The majorities 89% were female. More than half of the respondents 72.6% were Muslim and 63.83% of respondents have completed Diploma in nursing. About 32.2% respondents were living with senior citizen, 33% respondents were infected by COVID-19, 24.23% respondent mentioned nurse-Patient ratio in general ward was 1:7 and 71.08% mentioned nurse-patient ratio in I.C.U/C.C.U. was 1:3 (December 2021). PPE were available among 88.0% respondents and N95 mask were available among 84.0% respondent. About 34.8% respondents got COVID-19 guideline training and 32.4% got donning and doffing training. More than half of the respondents 76% stated that equipment is adequate, 56.38% respondents mention that insufficient of nurses and 53.7% were mentioned insufficient of subordinate staff. About 22.6% respondents faced social stigma and majorities 96.5% respondents mentioned they got proper family support. There was a significant association found between Professional educational qualification and satisfaction of current designation (p value = 0.001 Conclusion: The most important findings of this study was lack of training, insufficient of manpower especially nurses and subordinate s

关键词： Nurses’ Experiences Service Provision COVID-19 Tertiary Public Hospital

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Microwave assisted synthesis of poly（2-hydroxyethylmethacrylate） grafted agar （Ag-g-P（HEMA）） and its application as a flocculant for wastewater treatment

引用

Frontiers of Chemical Science and Engineering 2013年第3期7卷 312-321页

作者： Gautam SEN G. Usha rani Sumit MISHRA Department of Applied Chemistry Birla Institute of Technology Mesra Ranchi 835 215 India

poly（2-hydroxyethylmethacrylate） chains were grafted onto the backbone of agar using a microwave assisted method involving a combination of microwave irradiation and ceric ammonium nitrate to initiate the grafting reaction. The synthesized graft copolymers were characterized by intrinsic viscosity measurements, Fourier transform infrared spectroscopy, elemental analysis （C, H, N, O and S） and scanning electron microscopy. Ag-g-P （HEMA）-2 showed a much higher flocculation efficacy than agar. The optimized dosage of flocculation for Ag-g-P （HEMA）-2 in the wastewater was found to be 0.75 ppm. Compared to agar, Ag-g-P（HEMA）-2 was found to considerably reduce the pollutant load in the wastewater.

关键词： agar flocculant microwave assisted synth- esis jar test protocol poly(HEMA) grafted agar wastewater treatment

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Controlled drug release of 5-amino salicylic acid by poly（2- hydroxyethylmethacrylate） grafted agar

引用

Frontiers of Chemical Science and Engineering 2014年第4期8卷 465-470页

作者： G. Usha rani Kartick Prasad DEY Srijita BHARTI Sumit MISHRA Department of Chemistry Birla Institute of Technology Mesra Ranchi 835215 Jharkhand India

The utilization of poly （2-hydroxyethylmetha- crylate） grafted agar （Ag-g-P（HEMA）） as a matrix for the controlled release of 5-aminosalicylic acid was investi- gated. Grafted copolymers of 2-hydroxyethylmethacrylate （HEMA） monomers on agar were synthesized by micro- wave assisted method. In vitro drug release studies were performed at pH values of 2 and 7 in order to investigate the possibility of pH triggered release for colon targeted drug delivery. Further, the percent grafting vs. tso （the time taken for release of 50% of the enclosed drug） value was studied and the results indicate that it may be possible to develop a programmable drug release matrix based on grafted polysaccharide. Ag-g-P（HEMA） appears to be a useful matrix for controlled release.

关键词： agar controlled drug release 5-Amino sal-icylic acid poly(2-hydroxyethylmethacrylate) grafted agar

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of Maturity Indices on Growth and Quality of High Value Vegetables

引用

American Journal of Plant Sciences 2022年第7期13卷 1042-1062页

作者： A. K. M. Quamruzzaman Ferdouse Islam Limu Akter Sharmilla rani Mallick Olericulture Division Horticulture Research Center Bangladesh Agricultural Research Institute Gazipur Bangladesh Department of Horticulture Bangabandhu Sheikh Mujibur Rahman Agricultural University Gazipur Bangladesh

The study took place at Bangladesh Agricultural Research Institute’s Olericulture Division’s research farm from March 2021 to February 2022 (BARI). In a protected net house, we investigated the impact of five different types of vegetables on various maturation stages, including tomato, broccoli, sweet pepper, cucumber, and netted melon. Vegetables cultivated under protected conditions in a transparent poly-film net house can improve quality, maturity, fruit size, and yield. When fruits and vegetables are picked before they are fully mature, they may stay green for longer, but they may not ripen to a satisfactory color and flavor, resulting in a loss of consumer confidence. Furthermore, because fruit continues to grow until the harvest, immature fruit will be smaller than mature fruit, reducing harvest yield. We tried to determine the right maturation stages in order to avoid product loss during our investigation. The tomato was found to be an appropriate size (6.5 cm length and 6.2 cm diameter), weight (84 g), TSS (4.5 percent), pH (4.3), “turning red”, and “tasty” at the week 5 stage, while the broccoli was found to be an appropriate size (12.0 cm length and 13.0 cm diameter), weight (360 g), and “green” color at the week 5 stage. At the week 6 stage, the nettled melon was found to be of appropriate size (15.2 cm length and 14.5 cm diameter), weight (800 g), TSS (10.8 percent), pH (6.3), “net fully developed” on the fruit skin and “much tasty,” while cucumber was found to be of appropriate size (8.8 - 10.8 cm length and 2.2 - 2.9 cm diameter), weight (61 - 88 g), TSS (3.8 - 4.1 percent), pH (6.3), “less powdery”. As a result, establishing the optimal maturity of our research will benefit both consumers and growers.

关键词： Maturity Indices Growth Quality High Value Vegetables TSS pH Different Harvest Stages

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Effect of PVP, PVA and POLE surfactants on the size of iridium nanoparticles

引用

Open Journal of Inorganic Chemistry 2012年第3期2卷 67-73页

作者： Anjali Goel Neetu rani Department of Chemistry Kanya Gurukul Mahavidyalaya Gurukul Kangri University Hardwar (U.K) India

Commonly transition metal nano particle are synthesized by physical, chemical or electrochemical methods. In the present work colloidal iridium nanoparticles were synthesized by chemical oxidation method with different surfactants like poly vinyl pyrrolidone (PVP), poly vinyl alcohol (PVA) and poly oxyethylene lauryl ether (POLE). It was found that shape and size of Ir-nano particles resulted were related to kind of capping agent (surfactant) used. The characterization of the synthesized nano particle has been carried out by UV-vis, X-ray diffraction (XRD), FT-IR, scanning electron microscopy (SEM) and transmission electron microscopic (TEM) techniques. UV-vis and FT-IR confirm the oxidation of IrCl3 into IrO2 while XRD confirms the amorphous nature of the iridium nanoparticles synthesized. The morphology and size of the particle were confirmed by TEM. The average particle size determined by Scherrer equation was about 4.12 nm to 4.23 nm with PVP, 2.74 to 3.36 nm with PVA and 20.41 to 42.25 nm with POLE. poly oxyethylene lauryl ether particles were not further analyzed because of their large size and less stability. Further particle size was confirmed with TEM, which was 4.5 nm with PVP and 7.0 nm with PVA. The particles are spherical with no agglomeration tendency.

关键词： Nano-Materials Surfactant Agglomeration PVP PVA POLE

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

DC Conductivity and Spectroscopic Characterization of poly (o-toluidine) Doped with Binary Dopant ZrOCl<sub>2</sub>/AgI

引用

Materials Sciences and Applications 2011年第8期2卷 1049-1057页

作者： Kiran Kumari Vazid Ali Gita rani Sushil Kumar G.B.V.S. Lakshmi M. Zulfequar 不详

Aqueous binary dopant (ZrOCl2/AgI) is used in different ratio such as 1:1, 1:2 and 2:1 (w/w) for chemical doping to enhance the conductivity of synthesized poly (o-toluidine) (POT). The doping of poly (o-toluidine) is carried out using tetrahydrofuran as solvent. Doped samples are characterized using various techniques such as I-V characteristics, UV-Visible spectroscopy, X-ray diffractometry (XRD), FTIR and Photoluminescence (PL) studies. A significant enhancement in DC conductivity has been observed with the introduction of binary dopant. UV-Visible study shows that optical parameters change considerably after doping. Interestingly, both direct and indirect band gaps are observed in the doped samples. XRD patterns show the semi-crystalline nature of doped poly (o-toluidine). FTIR study shows structural modifications in functional groups with doping in POT. A Photolyminescence spectrum exhibits the emission properties of the samples.

关键词： poly (O-Toluidine) Dc Conductivity UV-Visible Study X-Ray Diffraction FT-IR And Photoluminescence Studies

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：