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Assessing the Pavement Quality of National Roads in Sudan 苏丹国道路面质量评价
Pub Date : 2021-08-29 DOI: 10.53332/kuej.v11i1.151
M. Zumrawi
Roads play a vital role in the sustainable economic development for many countries in the world. The quality of road pavement is considered to be one of the most important indicator of economic competitiveness. Therefore, it is very important for Sudan government and road authorities to maintain road networks with appropriate levels of quality and safety standards. The research conducted a field survey in four major national roads to collect data on surface distresses, determine the level of road quality, and identify the most important factors leading to road deterioration. The results obtained showed that 49.5% of the roads are in good condition, 24.4% are in fair condition, and 16.1% are in poor condition and the major distresses observed on roads’ surfaces are cracking and potholes failures. It was found that the main reasons for road deterioration are traffic overloading and climatic changes. Finally, recommendations are provided to help the government and road authorities in Sudan to improve the quality of road network.
道路在世界上许多国家的可持续经济发展中起着至关重要的作用。道路铺装质量被认为是衡量经济竞争力的重要指标之一。因此,苏丹政府和道路当局必须保持适当水平的质量和安全标准的道路网。该研究对四条主要国家公路进行了实地调查,以收集路面病害数据,确定道路质量水平,并确定导致道路恶化的最重要因素。结果表明,49.5%的道路状况良好,24.4%的道路状况一般,16.1%的道路状况较差,路面主要病害为裂缝和坑洼破坏。研究发现,道路恶化的主要原因是交通超载和气候变化。最后,提出了建议,以帮助苏丹政府和道路当局提高道路网络的质量。
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引用次数: 0
Fluoride Removal from Drinking Water Using Aluminium Oxide Coated Charcoal – effectiveness of repetitive regenerations 氧化铝包覆木炭去除饮用水中的氟化物——重复再生的有效性
Pub Date : 2020-02-03 DOI: 10.53332/kuej.v10i1.912
Motwkel M. E. Alhaj, B. Elhassan
There are many techniques to remove fluoride from drinking water. However, adsorption was found to be very effective and easy to apply. Along with this line, many studies were done to find an effective and affordable fluoride adsorbent. Activated Alumina (AA), Aluminum oxide coated sand (AOCS), pumice (AOCP), bauxite (AOCB) and charcoal (AOCC) were recently investigated. Nevertheless, AOCC found to be more promising for two reasons: it is cheap and can be regenerated. This paper aims to further contribute to feasibility of AOCC for fluoride removal in order to reduce the operation cost. Batch and continuous flow filter runs were conducted AOCC regenerated batch-wise, and used for the next filter run. AOCC was consequently regenerated three times. The results showed a considerable increase in AOCC fluoride adsorption capacity after each regeneration cycle. Characterization of virgin charcoal, virgin AOCC and regenerated AOCC after the first, the second and the third regeneration cycle, showed that virgin charcoal has highest specific surface area and micro porosity. For virgin AOCC and regenerated AOCC after the first, the second regeneration cycle a reduction in the specific surface area occurred, coupled with a reduction of micro porosity. AOCC after third regeneration cycle showed an increase in specific surface area likely due to aluminum hydroxide deposits on re-coated AOCC surface. Most of the pores after the third regeneration cycle were found to be meso pores. This means that, specific surface area alone cannot explain the increase in the AOCC adsorption capacity after regeneration. The paper recommends investigating the fluoride removal mechanism onto AOCC in order to produce affordable fluoride removal material from drinking water.
有许多技术可以去除饮用水中的氟化物。然而,吸附被发现是非常有效的,易于应用。在这条线上,许多研究都是为了找到一种有效和负担得起的氟化物吸附剂。近年来对活性氧化铝(AA)、氧化铝包覆砂(AOCS)、浮石(AOCP)、铝土矿(AOCB)和木炭(AOCC)进行了研究。然而,AOCC被发现更有前途的原因有两个:它便宜,可以再生。本文旨在进一步探讨AOCC除氟的可行性,以降低运行成本。分批和连续流过滤运行按批次进行AOCC再生,并用于下一次过滤运行。因此,AOCC再生了三次。结果表明,每次再生循环后,AOCC对氟的吸附量都有较大的提高。对经过第一次、第二次和第三次再生循环的原炭、原AOCC和再生AOCC的表征表明,原炭具有最高的比表面积和微孔隙率。原生AOCC和再生AOCC在第一次再生循环后,在第二次再生循环中,比表面积减小,微孔隙率降低。经过第三次再生循环后,AOCC的比表面积有所增加,这可能是由于再涂覆的AOCC表面沉积了氢氧化铝。第三次再生循环后的孔隙以介孔为主。这意味着,单靠比表面积不能解释再生后AOCC吸附量的增加。本文建议对AOCC的除氟机理进行研究,以期生产出经济实惠的饮用水除氟材料。
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引用次数: 0
Sudan Load Forecast for Period 2017 – 2066 Using Seasonal Time Series Model 使用季节时间序列模型预测2017 - 2066年苏丹负荷
Pub Date : 2019-03-12 DOI: 10.53332/kuej.v8i2.897
A. Khadam, K. Ramadan, E. Hamouda
The importance of this paper is the use of seasonal time series models (some seasonal models of Box & Jenkins) to predict electricity consumption in Sudan National Grid, making it easier to estimate consumption, and provide accurate indicators for planners to develop appropriate future plans in electricity sector. The objective of this paper is to forecast the electric load consumption using different model.
本文的重要之处是利用季节时间序列模型(Box & Jenkins的部分季节模型)预测苏丹国家电网的用电量,使其更容易估算用电量,并为规划人员制定合适的电力部门未来规划提供准确的指标。本文的目的是利用不同的模型对电力负荷消耗进行预测。
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引用次数: 0
Improving QoS for Real-time Traffic using Multiple Low Latency Queueing Scheduling Mechanisms 使用多种低延迟队列调度机制提高实时流量的QoS
Pub Date : 2019-03-12 DOI: 10.53332/kuej.v8i2.896
Mudathir Yousif, I. Abuel Maaly, M. Abbas
In this work, a Multiple Low Latency Queuing scheduling mechanism model is developed to improve the QoS performance for real time and critical mission data traffic in LTE mobile networks. The main objective of this model is to achieve minimum delay and improve the QoS for real time applications (like Live Video and Voice over LTE). In addition, issues likestarvation of lower priority queues and bandwidth allocation are addressed. The model is composed of four components, first, classifier to classify the incoming traffic in router interface. Second, four Class Based Weighted Fair Queues (CBWFQ) scheduling mechanisms, with activation of strict priority feature in the first two queues. Third, two separate rate limiters (policers), one for each strict priority queue. Two scenarios are designed and simulated using Optimized Network Engineering Tool (OPNET). The results show that, in the case of Multiple Low Latency Queuing scheduling mechanism model, the real time traffic suffers less delay compared to the case of existing scheduling mechanisms like (Custom Queuing, Priory Queuing, CBWFQ and Low Latency Queuing). On the other hand, the model also addressed the starvation of lower-priority queuesproblem.
为了提高LTE移动网络中实时和关键任务数据流量的QoS性能,提出了一种多低延迟队列调度机制模型。该模型的主要目标是实现最小延迟并提高实时应用(如LTE上的实时视频和语音)的QoS。此外,还解决了低优先级队列不足和带宽分配等问题。该模型由四个部分组成:一是分类器,对路由器接口的入站流量进行分类;其次,四种基于类的加权公平队列(CBWFQ)调度机制,在前两个队列中激活严格优先级特征。第三,两个单独的速率限制器(策略器),每个严格优先级队列一个。利用优化网络工程工具(OPNET)对两种场景进行了设计和仿真。结果表明,与现有调度机制(自定义队列、先验队列、CBWFQ和低延迟队列)相比,多低延迟队列调度机制模型的实时流量延迟较小。另一方面,该模型还解决了低优先级队列不足的问题。
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引用次数: 0
Development of an Empirical Coefficient for the Short Circuit Current to Determine Soiling Effect on PV Performance 短路电流经验系数的发展,以确定污染对PV性能的影响
Pub Date : 2017-12-10 DOI: 10.53332/kuej.v7i2.973
Abubaker Younis, M. Onsa, Y. Alhorr, Esam Elsarrag
In this study, the effect of dust accumulation on the performance of photovoltaic (PV) module has been shown. A statistical analysis has been conducted on a medium sized sample data collected from 30 hours of experimental work to obtain an empirical coefficient like temperature coefficients of short circuit current and open circuit voltage usually provided by manufacturers. This coefficient will be named dust coefficient of short circuit current and it will represent a predefined range of environmental conditions and soiling amounts; as the available testing conditions, and the statistical model prediction limits bound the coefficient extent of applicability.
本文研究了粉尘堆积对光伏组件性能的影响。对30小时实验工作中收集的中等样本数据进行统计分析,得到与一般厂家提供的短路电流温度系数、开路电压温度系数类似的经验系数。该系数将被命名为短路电流粉尘系数,它将表示预定义的环境条件和污染量范围;作为可用的试验条件,与统计模型的预测极限绑定了系数的适用范围。
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引用次数: 1
Dynamic Stability Control of Sudan National Grid Using Power System Stabilizer 利用电力系统稳定器对苏丹国家电网进行动态稳定控制
Pub Date : 2017-12-03 DOI: 10.53332/kuej.v7i2.968
I. Hassan, Kamal Romadan, Elamin Hamuda
Application of power system stabilizers (PSS), as supplementary control signals for the excitation system in order to damp the low frequency, generator angle, speed variation, generator power, voltage magnitude and power flow oscillations. This paper presents the application of robust decentralized power system stabilizer (PSS) design approaches, for Sudan power system which consists of 41 machines with 167 buses. The paper mainly focus on operator testing of robust decentralized control techniques for power systems, and the optimal control approach to robust control design. Results of robust decentralized control design approaches are defined by using state space model equations. Also for testing dynamic stability Lyapunov theorem is used. The simulations were carried out using symmetrical fault and results presented by Power System Analysis Toolbox, MATLAB.
电力系统稳定器(PSS)的应用,作为励磁系统的辅助控制信号,以抑制低频、发电机角度、转速变化、发电机功率、电压幅值和潮流的振荡。本文介绍了鲁棒分散电力系统稳定器(PSS)设计方法在苏丹电力系统中的应用,该系统由41台机器和167个母线组成。本文主要研究了电力系统鲁棒分散控制技术的算子测试,以及鲁棒控制设计的最优控制方法。利用状态空间模型方程定义了鲁棒分散控制设计方法的结果。对于动态稳定性的检验,也采用了李雅普诺夫定理。采用对称故障进行仿真,仿真结果由电力系统分析工具箱、MATLAB提供。
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引用次数: 0
Design of a Robust Decentralized Power System Stabilizer for Sudan National Grid 苏丹国家电网鲁棒分散电力系统稳定器的设计
Pub Date : 2017-12-03 DOI: 10.53332/kuej.v7i2.967
I. Hassan, Kamal Romadan, Elamin Hamuda
Power system stabilizers (PSS) are used to generate supplementary control signals for the excitation system in order to damp the low frequency, generator angle, speed variation, generator power, voltage magnitude and power flow oscillations. This paper presents robust decentralized power system stabilizer (PSS) design approaches for a power system consisting of 41 machines with 167 buses. This paper mainly focuses on developing robust decentralized control techniques for power systems, with special emphasis on problems that can be expressed as minimizing a linear objective function under linear matrix inequalities [LMI] in tandem with bilinear matrix inequalities [BMI] constraints. The design problem is considered the natural extension of the reduced order for decentralized dynamic output H2/H∞ -norm controller’s synthesis for power systems. The resulting optimization problem has a general bilinear matrix inequalities (BMIs) form which can be solved using an iterative linear matrix inequalities [LMIs] programming method. Simulations were carried out using loss of line without fault tests at transmission line on Sudan grid.
电力系统稳定器(PSS)用于为励磁系统产生补充控制信号,以抑制低频、发电机角度、转速变化、发电机功率、电压幅值和潮流振荡。针对由41台机器和167个母线组成的电力系统,提出了鲁棒分散电力系统稳定器的设计方法。本文主要研究了电力系统鲁棒分散控制技术的发展,特别强调了在线性矩阵不等式[LMI]和双线性矩阵不等式[BMI]约束下线性目标函数的最小化问题。该设计问题被认为是电力系统分散动态输出H2/H∞-范数控制器综合的降阶问题的自然推广。所得到的优化问题具有一般的双线性矩阵不等式形式,可采用迭代线性矩阵不等式规划方法求解。采用苏丹电网输电线无故障损耗试验进行了仿真。
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引用次数: 0
Laboratory Study of Steel Slag Used for Stabilizing Expansive Soil 钢渣稳定膨胀土的室内研究
Pub Date : 2017-06-11 DOI: 10.20448/JOURNAL.508.2017.41.1.6
M. Zumrawi, A. A. Babikir
This paper presents an experimental study in stabilization of expansive soil using Steel Slag (SS). Experimental program was conducted to evaluate the influence of Steel Slag on improving the engineering properties of expansive clay. A series of tests to measure consistency limits, free swell index, compaction parameters and unconfined compressive strength of natural and stabilized soils. The effectiveness of adding 0, 5, 10, 15, 20, and 30 percentages of SS to the soil was studied. Comparing the results obtained for the natural and stabilized soils, revealed that SS has significant effect on strength parameters and considerable improvement in plasticity and swelling properties. Addition of SS to the soil increased the dry density and decreased the optimum moisture content as well as increased the unconfined compressive strength. It is concluded that the use of steel slag to enhance properties of expansive soil is successful and beneficial.
本文进行了钢渣稳定膨胀土的试验研究。通过试验研究了钢渣对膨胀粘土工程性能的改善作用。一系列测试,以测量一致性极限,自由膨胀指数,压实参数和无侧限抗压强度的天然和稳定土。研究了在土壤中分别添加0、5、10、15、20、30 % SS的效果。对比天然土和稳定土的试验结果,发现SS对土的强度参数有显著影响,对土的塑性和溶胀性能有显著改善。添加SS增加了土壤的干密度,降低了土壤的最佳含水量,提高了土壤的无侧限抗压强度。结果表明,利用钢渣改善膨胀土的性能是成功的、有益的。
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引用次数: 13
Effect of Excavation Dewatering on Adjacent Structures 开挖降水对邻近结构的影响
Pub Date : 2017-04-19 DOI: 10.53332/kuej.v6i2.1001
M. Zumrawi, E. Hassan
The study aims to investigate the effect of dewatering technique on retained ground and adjacent existing structures in order to avoid any damages that may occur. The paper presents three cases of potential structure failure caused by ground settlement as a result of dewatering. Two current construction projects in Khartoum North were selected as a case study. The two projects are located near Blue Nile River where ground water table exists at shallow depths. Dewatering to reduce the groundwater level was carried out in the two sites to facilitate excavation works. The buildings and road pavements around the two sites suffered serious damages due to excessive differential settlements of the retained ground. The study results showed that there are numerous sources of risks associated with performing dewatering. Therefore, developing appropriate plan for dewatering before construction is essential to mitigate any adverse impacts and avoid risks.
本研究旨在探讨降水技术对保留地面及邻近既有结构的影响,以避免可能发生的破坏。本文介绍了降水引起的地面沉降引起结构潜在破坏的三个实例。选择喀土穆北部的两个在建项目作为案例研究。这两个项目位于地下水位较浅的青尼罗河附近。在两个地点进行了脱水以降低地下水位,以便进行挖掘工程。两个遗址周围的建筑物和道路由于遗留地面沉降过大而受到严重破坏。研究结果表明,有许多与脱水有关的风险来源。因此,在施工前制定适当的脱水计划对于减轻任何不利影响和避免风险至关重要。
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引用次数: 2
Production and Analysis of Characteristics of Biodiesel Produced from Waste Cooking Oil 废食用油制备生物柴油及其特性分析
Pub Date : 2017-04-06 DOI: 10.53332/kuej.v6i2.1000
H. Farouk, AbduAllah Husien, Hazim M Ali, S. Osama
There is increasing interest on waste cooking oils (WCO) as a cost-effective feedstock for biodiesel production. In this study, a one-step transesterification process was adopted to produce biodiesel at a laboratory scale from waste cooking oil with a low level of free fatty acids (A.V. 1.09 mgKOH/g). The maximum biodiesel yield obtained was 85.3% when using a combination of process parameters of 25% (v/v) methanol to oil ratio, 0.8% (w/w) of KOH, a maintained reaction time of two hours, reaction temperature of 60o C, and a stirring speed of 400 rpm. In the quest to optimize the process parameters such as alcohol to oil molar ratio, and catalyst concentration, the results show that the biodiesel yield increases with the increase in methanol to oil molar ratio until the optimum ratio, then starts to decrease and it decreases if the alkali catalyst is added above an optimum concentration. The optimum values of methanol to oil molar ratio and alkali catalyst were 25% (v/v) and 0.8% (w/w), respectively. The basic physicochemical properties of the WCO biodiesel produced were found to be within the ASTM Standard D6751 specified limits for required parameters. The principal parameters were acid value, density, viscosity and flash point. The calorific value was found to be 41.05 MJ/kg.
人们对废食用油作为生产生物柴油的一种经济有效的原料越来越感兴趣。本研究以低游离脂肪酸水平(A.V. 1.09 mgKOH/g)的废食用油为原料,采用一步酯交换法制备实验室规模的生物柴油。在甲醇油比为25% (v/v)、KOH用量为0.8% (w/w)、反应时间为2 h、反应温度为60℃、搅拌转速为400 rpm的条件下,生物柴油的最大产率为85.3%。在对醇油摩尔比、催化剂浓度等工艺参数进行优化的过程中,结果表明:随着醇油摩尔比的增加,生物柴油的产率逐渐增加,达到最佳产率后,生物柴油的产率开始下降,当碱催化剂的添加量超过最佳浓度时,生物柴油的产率下降。甲醇油摩尔比为25% (v/v),碱催化剂为0.8% (w/w)。生产的WCO生物柴油的基本物理化学性质被发现在ASTM标准D6751规定的所需参数限制范围内。主要参数为酸值、密度、粘度和闪点。热值为41.05 MJ/kg。
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引用次数: 1
期刊
University of Khartoum Engineering Journal
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