检索结果-南通市图书馆

The Utilization of Eucalyptus Oil for Reducing Methane Production in Ruminants under in Vitro Conditions

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

The Utilization of Eucalyptus Oil for Reducing Methane Produ...

作者： Safwat Mohamed abdelrahman ahmed Attia 吉林农业大学

学位级别：硕士

畜牧业产生的甲烷是引起全球变暖的主要因素。地球气候变暖成为全球重要问题之一。本研究中在体外条件下研究不同浓度的桉叶油对瘤胃中生产甲烷的抑制作用。试验设计为:不同精粗比的饲粮,分别为70:30和60:40。饲粮干物质中桉叶油的浓度... 详细信息

畜牧业产生的甲烷是引起全球变暖的主要因素。地球气候变暖成为全球重要问题之一。本研究中在体外条件下研究不同浓度的桉叶油对瘤胃中生产甲烷的抑制作用。试验设计为:不同精粗比的饲粮,分别为70:30和60:40。饲粮干物质中桉叶油的浓度分别为0 mL/kg、2 mL/kg、4 mL/kg、6 mL/kg、8 mL/kg和10 mL/kg。试验采用的瘤胃原液从两只健康瘘管绵羊获取,分别在3 h、6 h、9 h、12 h、24 h、36 h、48 h和72 h,检测气压(GP)、甲烷产量(CH4)。发酵(72 h)结束后,检测挥发性脂肪酸(VFA)、氨态氮(NH3)、干物质降解率(DMD)及有机物降解率(OMD)、pH值和原生动物数等。结果表明,不同浓度的桉叶油处理条件下,甲烷产量有所降低(P<0.05)。在精粗比30:70的处理中,2 mL/kg组的甲烷产量较对照组减少32%,10 mL/kg组的甲烷产量较对照组减少38%。在精粗比60:40的处理中,2 mL/kg组的甲烷产量较对照组减少42%,10 mL/kg组的甲烷产量较0 mL/kg组减少46%。在所有精粗比处理中,通过提高桉叶油的浓度,与0 mL/kg组相比,原虫数量显著下降(P<0.05)。NH3浓度较0 mL/kg组下降,在精粗比为60:40组中不显著,在70:30中显著(P<0.05)。在所有精粗比处理中,随着桉叶油浓度的提高,A/P值、DMD和OMD都显著下降(P<0.05)。除了精粗比70:30处理中的10 mL/kg组,其他各组的pH值没有显著差异。综上,2 mL/kg组为效率最高组。该浓度的桉叶油降低甲烷气体为最佳浓度。同时成本也是最低的。

关键词：污染瘤胃桉叶油甲烷反刍动物

Impact of Pulsed Laser Parameters and Scanning Pattern on the Properties of Thin-Walled Parts Manufactured Using Laser Metal Deposition

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

Nanomanufacturing and Metrology 2022年第4期5卷 381-393页

作者： Weiwei Liu Gamal Al-Hammadi Kazi Mojtaba Saleheen ahmed abdelrahman Huanqiang Liu Zhidong Zhang School of Mechanical Engineering Dalian University of TechnologyDalian116024China Liaoshen Industries Group Co. LtdShenyang110041China

The quality of parts manufactured using laser metal deposition(LMD),similar to other additive manufacturing methods,is influenced by processing *** parameters determine geometric stability,favorable microstructures,and good mechanical *** study aimed to investigate the effects of pulsed laser parameters(duty cycle and pulse frequency)and scanning patterns(unidirectional and bidirectional patterns)on the properties of parts fabricated using *** show that the properties of the LMD-fabricated parts are obviously influenced by pulsed laser parameters and scanning *** the unidirectional scanning pattern in both pulsed laser parameters enhances the properties of the thin-walled parts prepared using *** increase in duty cycle can improve geometric stability,increase grain size,and reduce ***,the geometric stability does not vary considerably with the use of different frequencies,but the microstructure of fabricated parts shows various grain sizes with different pulse *** addition,the microhardness increases as the frequency increases from 13.33 to 50 *** general,the influence of the duty cycle on geometric properties is greater than that of ***,the impact of frequency on microhardness is greater than that of the duty cycle.

关键词： Laser metal deposition(LMD) Pulse laser Scanning pattern Geometric properties Grain size Hardness

Hybrid Repair of Two Consecutive Acute Ventricular Septal Ruptures after Evolving Myocardial Infarction: Case Report

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Cardiovascular Surgery 2021年第4期11卷 37-42页

作者： Adel Mohammad Makhdoom ahmed abdelrahman Elassal Department of Anesthesia and Intensive Care King Abdulaziz University Jeddah Saudi Arabia Department of Surgery Cardiac Surgery Unit King Abdulaziz University Jeddah Saudi Arabia Cardiothoracic Surgery Department Zagazig University Zagazig Egypt

Background: Acute Ventricular septal rupture is one of dreadful complications of acute evolving myocardial infarction. Despite urgent management is lifesaving, it is still challenging and has a high risk of mortality particularly if recurrent or residual defects occurred. Evolving of skillfulness in transcatheter intervention of heart diseases paved the way for successful hybrid management of challenging cardiac cases specially for residual complicated cases post cardiac surgery. Case Presentation: We described here a successful hybrid two stage technique (surgical then transcatheter approach) to close two consecutive acute ventricular septal ruptures in 75 years old female presented with cardiogenic shock post evolving myocardial infarction. Conclusion: Hybrid repair by surgical and transcatheter interventions may be a good therapeutic modality for acute septal ruptures specially for residual or new defects after initial closure.

关键词： Hybrid Repair Ventricular Septal Rupture

The Prevalence of Human Metapneumovirus among Children with Acute Respiratory Tract Infection in North Kordofan State, Sudan

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Molecular Biology 2020年第4期10卷 259-264页

作者： Huzifa Abdalla abdelrahman ahmed Nassreldeen Khalid abdelrahman Mudathir Abdallah Adam Faculty of Medicine Sudan International University Khartoum Sudan Faculty of Medical Laboratory Science University of Al Fashir Al Fashir Sudan

Objective: To determine the prevalence of human metapneumovirus (hMPV) among children with acute respiratory tract infection and the correlation between (hMPV) and age group. Methods: This prospective, descriptive cross-sectional hospital-based study is carried out from January to May 2019 among children from under five years old who were admitted to El-Obeid pediatric teaching Hospital, North kordofan, Sudan with acute respiratory tract infection. Results: Fifty hospitalized children with acute respiratory tract infection were enrolled in the study. Two of these (4%) were tested positive for (hMPV) in the age group (7 months - 2 years) old. Moreover, the study showed no significant correlation between infection with (hMPV) and age.

关键词： Human Metapneumovirus Respiratory Tract Infection Real Time Sudan

Bacterial Contamination of Drinking Water in the Internally Displaced People Camps in South Darfur, Sudan

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computational Water, Energy, and Environmental Engineering 2013年第2期2卷 10-12页

作者： Yassir Mohammed Eltahir Amira ahmed abdelrahman Department of Environmental Health Administration State ministry of Health South Darfur State Nyala Sudan Department of Preventive Medicine and Veterinary Public Health Faculty of Veterinary Science Nyala University Nyala Sudan

A total of 240 water samples were collected during the three seasons of 2009 from different sites and sources in the internally displaced camps (IDP) including bore holes, hand pumps, dug wells, water points, water reservoir and household storage containers. Samples were investigated using the most probable number method to detected and count the total coliform, faecal coliform and faecal enterococci. Enteric bacteria detected were E. coli, Enterococcus faecalis, Klebsiella, Citrobacter and Enterobacter .House hold containers showed continuous level of contamination by all different bacteria throughout the three seasons. This was followed by hand pumps, both reservoir and boreholes and dug wells. Water points revealed no level of contamination throughout the three seasons.

关键词： Water Microbiology Bacterial Contamination E.coli

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

回收废旧轮胎用热解的商业计划

回收废旧轮胎用热解的商业计划

作者： Rayan abdelrahman ahmed Mohamed 上海外国语大学

学位级别：硕士

本文的研究目的是通过采用新的技术,如高温分解的方法,更加环保经济地回收旧轮胎。高温分解是一个让轮胎变成油的过程,炭黑,气,或者钢铁,如果橡胶里有钢铁的话,这个过程不需要氧气就可以了。本文的研究数据是二手的。以苏丹为例,苏丹每... 详细信息

本文的研究目的是通过采用新的技术,如高温分解的方法,更加环保经济地回收旧轮胎。高温分解是一个让轮胎变成油的过程,炭黑,气,或者钢铁,如果橡胶里有钢铁的话,这个过程不需要氧气就可以了。本文的研究数据是二手的。以苏丹为例,苏丹每年收集到的零碎橡胶数量是60,000吨。我们这个项目每年的可供给量是大概5,000吨。这个项目会对整个苏丹市场带来好的机会,根据我们的研究,发现中国能提供很好的技术。所以我们打算进口设备,产能是每天10吨。我们选择了苏丹的首都喀什穆,因为原材料的供给很好。从经济角度分析,这个项目收益性不错,投资的回报率预计是52%,如果我们100%的使用这个机器,还本期是3.6年,包括安装期和建设期在内。另外,原材料的成本在敏感度上排第二。理论上,我们发现就算没有钢铁和炭黑的销售,这个项目仍然是盈利的。另外,这个项目有另外的好处,就是对环境和社会友好,因为这个新的技术可以回收利用废旧的轮胎。我们的建议是尽快启动这个项目。

关键词：废旧轮胎管理废旧轮胎热解项目可行性研究

Performance Analysis with Channel Estimation and Adaptive Equalization in Slow Rayleigh Fading Channel for8-QPSK and256-QAM

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

Performance Analysis with Channel Estimation and Adaptive Eq...

作者： ahmed Mohamed Ali abdelrahman 湖南大学

学位级别：硕士

在过去的几十年里,因为在对抗多径衰落信道中支持高数据速率和有效性,人们已经对多载波系统进行广泛的研究。多载波调制(MCM)是将数据流分成几个并行的比特流,每个比特率要低得多,并通过使用这些比特流传输数据。多载波调制(MCM)代表目... 详细信息

在过去的几十年里,因为在对抗多径衰落信道中支持高数据速率和有效性,人们已经对多载波系统进行广泛的研究。多载波调制(MCM)是将数据流分成几个并行的比特流,每个比特率要低得多,并通过使用这些比特流传输数据。多载波调制(MCM)代表目前和未来的高速数字通信。许多新的有线和无线通信应用要求高数据速率和大的带宽。MCM通过正交频分复用(OFDM)的形式应用于在一些如数字音频广播(DAB),数字视频广播(DVB)和无线局域网(WLAN)的无线通信系统中。正交频分复用(OFDM)引入了有限的物理信道带宽内分配更多的交通信道的概念。因此,可用带宽分成几个同时传输的窄带通道。在频分复用,保护带提供个人之间的通道,分隔不同的渠道,能够使用特殊的频段检测通道。在相邻信道的OFDM中不同的频率划分重叠类似于相邻信道干扰,但子载波之间保持正交关系。通过采用OFDM,这是有可能实现对多径信道的高的频率利用率和鲁棒性。在OFDM系统中,调制技术,如BPSK(二进制相移键控)和多级正交调幅(M-QAM)映射到信号星座符号固定数量的信息比特。每个信号的星座符号代表在二维的基带信号空间的一个点。在这篇论文中,我们将测试三种不同的通道(AWGN信道,平坦衰落信道,频率选择性信道)下,数据和图像通过256-QAM和8-QPSK调制接收星座和误码率(BER)。为了比较模拟信道衰落和接收器的设计,我们首先需要选择的相应的标准。目前有很多的根据信道衰落和需要估计标准,如OFDM, CDMA RAKE接收机,MIMO技术等。在本文中,我们选择OFDM标准。我们首先使用MATLAB建立一个无线通信模拟器,包括灰度编码,调制,三通道模式,信道估计,自适应均衡和解调。在我们的模拟中,我们测试不同的信道模式下的256-QAM和8-QPSK的调制星座图和误码率(BER)。在此模型中,我们使用的基于导频信道估计。这是因为导频信息是由接收器使用以便更好地估计在传播符号的频率衰落下有者更高数据接收率。在我们的模型,试验数据的长度是数据总长度的8%,并插入到每个相干时间源数据的头节点。我们还可以使用最小均方(LMS),自适应均衡,以帮助消除无线通道的影响以方便解调。对于图像而言,我们比较在不同的渠道收到的图像和原始图像。在瑞利慢平坦衰落信道,我们比较接收和调整后的图像。另一方面,在瑞利慢衰落信道频率选择性,我们测试在两个不同的模式(判决引导和训练)下接受到的图像。在我们的模型,测试图像文件给我们不同的信道比较下直观的印象。最后,我们给出详细结果和分析在慢瑞利衰落信道下信道估计和自适应均衡的性能改善。仿真结果表明,不像8QPSK在随机数据下平坦衰落信道仿真结果,256-QAM的误码率性能几乎与理论误码率相同。此外,使用256-QAM编码,在频率选择性衰落信道的中决策指示比培训模式的误码率更好,大多数情况下接近理论值。此外,通过比较图像文件,我们可以得到,在频率选择性衰落信道中,决策指挥模式下的256-QAM几乎接近原始图像的质量。这意味着,在256-QAM,均衡的图像不受任何噪音影响。这是因为256-QAM可以发送8位符号这是非常有效率,不同于8-QPSK,受到一些随机噪声导致图像的重叠。

关键词：信道估计 AWGN 慢衰落平坦衰落和频率选择性衰落

Assessing Drug Use Indicators in Health Insurance Facilities, Gezira State, Sudan, 2017-2018

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

Pharmacology & Pharmacy 2021年第10期12卷 237-246页

作者： Sara abdelrahman ahmed Elnazeer Ibrahim Hamedelniel Abubakr Khidir Yousif Medical Service Directorate National Health Insurance Fund Gezira Sudan Department of Pharmaceutics College of Pharmacy Omdurman Islamic University Omdurman Sudan MPH MHPE National Health Insurance Fund Gezira Sudan

Background: Inappropriate use of medicines is a global concern with serious consequences related to prescribing, dispensing, and use. WHO estimated that 50% of medicines are not used correctly on their journey from the facility to home. Objective: To assess medicines use using WHO drug core indicators regarding prescribing, patient, and facilities. Setting: Outpatients, Health centers in Wadmadani locality (Urban area) in Gezira State, Sudan. Method: A cross-sectional, prospective, analytical study was conducted in 30 health centers and 60 patients from each center were selected using a simple random sampling technique. WHO indicators form was used to collect data containing different variables. T-test at a level of confidence of 95% was used to test differences between indicators. Statistical Package for Social Science (SPSS) was used for data analysis. Results: The main prescribing indicators were 2.5 ± 0.6 for drugs per encounter, 44.1% ± 14.2%. Generic 54 ± 18.0 antibiotics, 12.0% ± 9.3% injectable, and 95.2% ± 11.5% of drugs were prescribed according to the NHIF-EML. The main patient’s indicators were, 2.9 ± 0.8 minutes for consultation time, 99.5 ± 36.8 seconds for dispensing time, and 72.5% ± 16.0% for medicines actually dispensed, 49.0% ± 18.0% for medicines adequately labeled, and 22.5% ± 7.3% of the patient

关键词： Assessing Drug Use Indicators National Health Insurance Fund Gezira Sudan

Pericardial Strip versus Ring Annuloplasty for Repair of Functional Tricuspid Regurgitation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Cardiovascular Surgery 2014年第12期4卷 239-244页

作者： Husain Hamza Jabbad ahmed abdelrahman Elassal Osama Saber Eldib Cardiothoracic Surgery Department (KAUH) Zagazig University Zagazig Egypt

Background: Functional tricuspid regurgitation is a challenge regarding indications for repair and proper surgical technique. Aim of the study: We reviewed our midterm results of tricuspid valve repair for functional regurgitation comparing pericardial strip versus ring annuloplasties. Patients and methods: From January 2008 to December 2013, we operated 59 patients (male:female, 41:18, with a mean age of 34 ± 14 years) for functional tricuspid regurgitation. Tricuspid annuloplasty was done using pericardial strip in 39 patients and ring in 20 patients. Concomitant procedures were mitral valve replacement in 66% of patients, aortic valve replacement in 5% and double valve replacement in 29%. Clinical and echocardiographic data were collected. Results: Preoperative characteristics of the two groups were similar regarding age, percentage of female patients, New York Heart Association functional class and pulmonary artery pressure. More patients with preoperative right ventricular dysfunction were found in pericardial annuloplasty group although this was not statistically significant (13 versus 5;P = 0.52). Operative times were similar in both groups. We had one mortality case (1.69%) due to low cardiac output in the pericardial group. Postoperative complications included reexploration for bleeding in one patient and chronic heart failure in another patient. The average follow up period was 3 years and it was complete in 100% of patients. Postoperative freedom from recurrent moderate tricuspid regurgitation was 90% in both groups. Conclusion: Pericardial strip annuloplasty is a simple, inexpensive, reproducible and efficient technique that has comparable results to ring annuloplasty.

关键词： Pericardial Strip Annuloplasty Tricuspid Ring Annuloplasty Functional Tricuspid Regurgitation