bluuebunny/crossref_metadata_2025 huggingface dataset:
Tailings From Mining Activities, Impact on Groundwater, and Remediation
Authors: Al-Rawahy Khalid
Published: May 2017

Effluent wastes from mining operations and beneficiation processes are comprized mostly of the following pollutants: total suspended solids (TTS), alkalinity or acidity (pH), settleable solids, iron in ferrous mining, and dissolved metals in nonferrous mining. Suspended solids consist of small particles of solid pollutants that resist separation by conventional means. A number of dissolved metals are considered toxic pollutants. The major metal pollutants present in ore mining and beneficiation waste waters include arsenic, cadmium, copper, lead, mercury, nickel, and zinc. Tailings ponds are used for both the disposal of solid waste and the treatment of waste-water streams. The supernatant decanted from these ponds contains suspended solids and, at times, process reagents introduced to the water during ore beneficiation. Leakage of material from tailings pond into groundwater is one possible source of water pollution in the mining industry. Percolation of waste-water from impoundment may occur if tailings ponds are not properly designed. This paper addresses potential groundwater pollution due to effluent from mining activities, and the possible remediation options.
The Development of a Database Management in GIS Applications in Oman
Authors: Osman Akif Osman Abdallah
Published: May 2017

The development of applying database management applications is currently underway within Geographical Information Systems (GIS) applications in the Sultanate of Oman.The establishment of a national database management system in Oman is considered as the backbone that is required within the Geographic Information System project in Oman. The principal of the GIS project in Oman was built upon unifying the used software packages over the sultanate which is ARC/INFO as GIS Package and ORACLE as database management software. These packages are used within the different participating Ministries in the GIS project in Oman.The participating ministries will handle information that are shared between them. The shared information among the different ministries is the attributed data which is defined as descriptive information extracted from geographic features that usually existed on the topographic maps and the ministries maps (utility maps). The map features can be classified into different layers according to the principles of ARC/INFO GIS Package. Accordingly, the main objectives of this research paper is to explain the technique proposed for establishing a national database management system that can handle and manage the shared information amongst the participating ministries in the project. The proposed database design will be made using the ORACLE database management system. Moreover, the paper will handle a proposed idea for linking the geographic map layers with the corresponding attributed database in order to create Geographic Information System applications. As a Conclusion, it is Proposed that all the government GIS departments in the Sultanate will share the same information within a unique national database management which can be considered one of the major benefits in applying database management in the field of Geographic Information Systems.
Problems of Bacteriological Pollution in Water Wells in Wadi Hadramout Water Project
Authors: Bin Qadhi Salem M. , Bashir Saeed Y. , Assaggaf Taha O.
Published: May 2017

This paper presents an existing problem of drinking water pollution for a small project and one of the model projects of drinking water in Yemen, designed to save and preserve good quality water for the present and future generations in the area. The paper gives the details of the project and explains the problem of bacteriological pollution and the steps undertaken to solve the problem. Some of the results for short-term solutions and recommendation for the long-term solutions are also given.
Design of all Optical Packet Switching Networks
Authors: Mouftah Hussein T.
Published: May 2017

Optical switches and wavelength converters are recognized as two of the most important DWDM system components in future all-optical networks. Optical switches perform the key functions of flexible routing, reconfigurable optical cross-connect (OXC), network protection and restoration, etc. in optical networks. Wavelength Converters are used to shift one incoming wavelength to another outgoing wavelength when this needs to be done.  Always residing in optical switches, they can effectively alleviate the blocking probability and help solve contention happening at the output port of switches. The deployment of wavelength converters within optical switches provides robust routing, switching and network management in optical layer, which is critical to the emerging all-optical Internet. However, the high cost of wavelength converters at current stage of manufacturing technology has to be taken into consideration when we design node architectures for an optical network. Our research explores the efficiency of wavelength converters in a long-haul optical network at different degrees of traffic load by running a simulation. Then, we propose a new cost-effective way to optimally design wavelength-convertible switch so as to achieve higher network performance while still keeping the total network cost down. Meanwhile, the routing and wavelength assignment (RWA) algorithm used in the research is designed to be a generic one for both large-scale and small-scale traffic. Removing the constraint on the traffic load makes the RWA more adaptive and robust. When this new RWA works in conjunction with a newly introduced concept of wavelength-convertible switches, we shall explore the impact of large-scale traffic on the role of wavelength converter so as to determine the method towards optimal use of wavelength convertible switches for all-optical networks.
Design of Ultra Fast RCE Photodetectors for Optical Communications systems
Authors: Jervase Joseph A. , Bourdoucen Hadj
Published: May 2017

Two key parameters for RCE photodetectors that govern their suitability for ultrafast optical communication systems are considered. These are the quantum efficiency and the bandwidth efficiency product. A closed analytical form has been derived for quantum efficiency, which incorporates the structural parameters of the photodetector. Based on the simulation results, an optimization and design procedure for these photodetectors has been developed.
MATLAB and PSPICE Dynamic Model of Axial-Field Permanent-Magnet Motor
Authors: Al-Badi A.H. , Gastli A.
Published: May 2017

In this paper a dynamic model of the axial-field, permanent-magnet machine will be discussed. The model may be used to study the transient response with the machine operating as a motor or as a generator. Experimental results are compared with Matlab/Simulink and Pspice predictions for a number of conditions, including the complete starting transient. Excellent correlation is obtained which validated both modeling approaches.
E-Business Development : A Strategic View
Authors: Bakry Saad Haj
Published: May 2017

E-business is becoming increasingly important for countries, organizations and individuals, as it gives them efficiency, and as it integrates them together, and with the world at large. This paper aims at providing a strategic view of the development of e-business. It starts by identifying e-business, and by reviewing its current progress. It then presents an e-business development profile, that defines the various elements associated with it. Based on the profile, the paper then provides future development guidelines, and identifies recommended plans.
Simulation of m-Sequence’s Properties Through MATLAB-SIMULINK
Authors: Ahmad A. , Al-Mushrafi M. J. , Al-Busaidi S.
Published: May 2017

Based on an analytical study of the theory of m-sequences, a tool is developed to facilitate practicing engineers to either generate m-sequence for its application, or to test applied m-sequence, or both. The developed test–kit simulates all the properties of m-sequences including number of 1s and 0s, the run lengths, pulse periods as well as autocorrelation properties.  This simplified tool is developed using MATLAB–SIMULINK with required codes as well as desired blocks. The model is cost-effective and the output files of the generated SIMULINK models can be utilized in any software program or simulation procedures.
Multi-Agents Architecture for Scheduling and Control of Robotic Manufacturing Systems
Authors: Bouzouia Brahim
Published: May 2017

This paper presents an  innovative Multi-Agent approach related to an advanced real time control  of flexible manufacturing systems. The proposed architecture is based on the paradigm of Distributed Intelligence and Multi-Agent Systems. The developed  Multi-Agent prototype system integrates  the following functions: Scheduling, dispatching, monitoring and error handling. A new negotiation protocol for manufacturing systems is presented in this paper. The purpose of this protocol is to assign dynamic operations to the resources of the Manufacturing System in order to accomplish the proposed tasks. This protocol is able to deal with exceptions.
Neural-Network-Based Fuzzy Logic Navigation Control for Intelligent Vehicles
Authors: Farah Ahcene , Chohra Amine
Published: May 2017

This paper proposes a Neural-Network-Based Fuzzy logic system for navigation control of intelligent vehicles. First, the use of Neural Networks and Fuzzy Logic to provide intelligent vehicles  with more autonomy and intelligence is discussed. Second, the system  for the obstacle avoidance behavior is developed. Fuzzy Logic improves Neural Networks (NN) obstacle avoidance approach by handling imprecision and rule-based approximate reasoning. This system must make the vehicle able, after supervised learning, to achieve two tasks: 1- to make one’s way towards its target by a NN, and 2- to avoid static or dynamic obstacles by a Fuzzy NN capturing the behavior of a human expert. Afterwards, two association phases between each task and the appropriate actions are carried out by Trial and Error learning and their coordination allows to decide the appropriate action. Finally, the simulation results display the generalization and adaptation abilities of the system by testing it in new unexplored environments.
Information Security Risks on a University Campus
Authors: Al-Rawas Amer A. , Millmore S.
Published: May 2017

This paper is concerned with issues relating to security in the provision of information systems (IS) services within a campus environment. It is based on experiences with a specific known environment; namely Sultan Qaboos University. In considering the risks and challenges that face us in the provision of IS services we need to consider a number of interwoven subject areas.  These are: the importance of information to campus communities, the types of information utilised, and the risk factors that relate to the provision of IS services. Based on our discussion of the risk factors identified within this paper, we make a number of recommendations for improving security within any environment that wishes to take the matter seriously. These recommendations are classified into three main groups: general, which are applicable to the entire institution; social, aimed at the work attitudes of staff and students; and technical, addressing the skills and technologies required.
A Fluid Film Squeezed Between Two Parallel Plane Surfaces Subject to Normal Oscillations
Authors: Hamza E. A.
Published: May 2017

We study the motion which results when a fluid film is squeezed between two parallel surfaces in relative motion.  Particular attention is given to the special case where one surface is fixed and the other is impulsively accelerated from a state of rest to a state of sinusoidal oscillations in a direction normal to its plane. In addition to the presentation of analytic solutions which are based on the regular perturbation technique and on the linearised analysis of the resulting nonlinear partial differential equation, a numerical solution of the full nonlinear equation based on a finite-difference scheme is obtained. The effects of the sinusoidal motion on the velocity profiles and on the normal forces which the fluid exerts on the surfaces are investigated.
Periodic Solutions of a System of Delay Differential Equations for a Small Delay
Authors: Wasike Adu A.M. , Ogana Wandera
Published: May 2017

We prove the existence of an asymptotically stable periodic solution of a system of delay differential equations with a small time delay t > 0. To achieve this, we transform the system of equations into a system of perturbed ordinary differential equations and then use perturbation results to show the existence of an asymptotically stable periodic solution. This approach is contingent on the fact that the system of equations with t = 0 has a stable limit cycle. We also provide a comparative study of the solutions of the original system and the perturbed system.  This comparison lays the ground for proving the existence of periodic solutions of the original system by Schauder's fixed point theorem.
Effect of Cold and Hot Temperature on Behavioral and Selected Physiological Measures of Uromastyx aegyptius (Agamidae)
Authors: El-Banna A.A. , Al- Johany A.M.
Published: May 2017

The behavioral, physiological and biochemical response to low (2°C) and high (45°C) temperatures was studied in Uromastyx aegyptius. Twelve animals were divided into two experimental groups. A third control group was kept at 22 °C.  All animals in the cooling, warming, and control groups were allowed a period of 24 hours for adjustments at 22 °C.  Blood samples were collected from each animal when body temperature reached the corresponding levels. The results showed a significant (P<0.05) decrease in blood glucose and cholesterol levels during cooling (2°C). This reduction in extracellular fluid substrates reflects an increase in cellular uptake of these substrates. Warming (45°C) resulted in a significant  (P< 0.05) increase in total proteins, urea, and uric acid. These later changes could be attributed to an increase in the evaporative water loss, particularly due to the increased observed panting, and the associated reduction in plasma volume. There were no significant (P>0.05) changes in T3 and T4, during cooling nor during warming. The results of this study suggest augmentation of anaerobic metabolism of the U.aegyptius during cooling as evident by reduction in blood glucose levels. Furthermore, shift of glucose from the extracellular to the intracellular fluids demonstrates anticipation against potential freezing in order to protect the animal from intracellular freezing.
Physiological and Behavioral Adjustments Relative to Catecholamine Levels During Nesting in Olive Ridley (Lepidochelys Olivacea) and Hawksbill (Eretmochelys Imbricata) Sea Turtles in Masirah Island, Oman.
Authors: AlKindi A.Y.A , Mahmoud I.Y. , Al-Siyabi Fatma
Published: May 2017

Plasma adrenaline (ADR) and noradrenaline (NA) levels were measured for the first time in natural populations of hawksbill (Eretmochelys imbricata) and olive ridley (Lipedochelys olivacea) in Masirah Island, Arabian Sea; one of the few protected nesting grounds remaining in the world for these two endangered species. Plasma ADR and NA levels were assessed in individuals after they oviposited eggs and completed nesting exercises, and in individuals which were still searching for suitable nesting sites. Blood samples were taken from the cervical sinuses from two groups (oviposited and non-oviposited), which spent at least 1.5 h on the nesting grounds. The duration of the nesting period varied between 1.5 and 2.0 h for both species. There was no significant difference between oviposited and non-oviposited turtles in both species. As the turtles move onto the nesting grounds, their heavy weight compresses the thoracic region making terrestrial breathing laborious and difficult. During phases of nesting, the turtles undergo brief bursts of strenuous and exhaustive exercise which usually lasts less than one minute followed by a brief recovery period which is less than the exercise phase. Reptiles in general, particularly turtles, are intermittent breathers and after bursts of exercise, they appear to develop hypoxia, hypercapnia and acidemia, which are characteristic of anaerobic metabolism. The data reveals that catecholamine levels remain stable in both species during phases of nesting and may play an important role in combating stress as well as mobilizing energy reserves. The high plasma lactate and CO2 levels in olive and hawksbill turtles may signify anaerobic metabolism during exercise. Glucose levels remain unchanged throughout nesting in both species. There was no significant difference in the lactate and glucose values in the two species. The physiological and the behavioral adjustments in this study showed remarkable similarities in the two species and may be an important factor in the reproductive strategy for species survival.
Characterizations of K- Semimetric Spaces
Authors: Mohamad Abdul M.
Published: May 2017

In this paper, we prove, for a space X, the following are equivalent:1. X is a D1 space with a regular-Gδ-diagonal,2. X is a D2 space with a regular-Gδ-diagonal, 3. X is a semi-developable space with Gδ (3) -diagonal, 4. X is a D1-space with a Gδ(3)-diagonal, 5. X is a D2 -space with a Gδ(3)-diagonal, 6. X is a q, -space with a G*δ (2)-diagonal, 7. X is a semi-developable space with G*δ (2)-diagonal, 8. X is a semimetrizable, c-stratifiable space, 9. X is a c-Nagata -space, 10. X is a K-semimetrizable.
A New Approach to the Stabilization of the Wave Equation with Boundary Damping Control
Authors: Chentouf Boumediène , Boudellioua Mohamed S.
Published: May 2017

This paper deals with boundary feedback stabilization of a system, which consists of a wave equation in a bounded domain of , with Neumann boundary conditions. To stabilize the system, we propose a boundary feedback law involving only a damping term. Then using a new energy function, we show that the solutions of the system asymptotically converge to a stationary position, which depends on the initial data. Similar results were announced without proof in (Chentouf and Boudellioua, 2004).
Optimal Control of Switching Linear Systems
Authors: Benmerzouga Ali
Published: May 2017

A solution to the control of switching linear systems with input constraints was given in Benmerzouga (1997) for both the conventional enumeration approach and the new approach. The solution given there turned out to be not unique. The main objective in this work is to determine the optimal control sequences {Ui(k) ,  i = 1,..., M ;  k = 0, 1, ...,  N -1} which transfer the system from a given initial state  X0  to a specific target state  XT  (or to be as close as possible) by using the same discrete time solution obtained in Benmerzouga (1997) and minimizing a running cost-to-go function. By using the dynamic programming technique, the optimal solution is found for both approaches given in Benmerzouga (1997). The computational complexity of the modified algorithm is also given.
On Regression Estimators Using Extreme Ranked Set Samples
Authors: Samawi Hani M. , Al-Samarraie Ahmed Y.A. , Al-Saidy Obaid M.
Published: May 2017

Regression is used to estimate the population mean of the response variable, , in the two cases where the population mean of the concomitant (auxiliary) variable, , is known and where it is unknown. In the latter case, a double sampling method is used to estimate the population mean of the concomitant variable. We invesitagate the performance of the two methods using extreme ranked set sampling (ERSS), as discussed by Samawi et al. (1996). Theoretical and Monte Carlo evaluation results as well as an illustration using actual data are presented. The results show that if the underlying joint distribution of and  is symmetric, then using ERSS to obtain regression estimates is more efficient than using ranked set sampling (RSS) or  simple random sampling (SRS).
Conformity of Physical Characteristics of Imported Tires with Government Standards: A Case Study
Authors: Ratrout N.T. , Basha S. Anwar , Wahhab H. I. Al-Abdul , Al-Ofi K. A.
Published: May 2017

The Saudi Arabian Standards Organization, SASO, has established a set of tests that all passenger car tires have to pass in order to be allowed into the Country. These tests are: visual inspection, dimension measurement, bead unseating, tensile strength and elongation, aging, endurance, and high speed performance tests. This paper describes the application of the first five tests on eight different brands of tires that are taken to represent the categories of “frequently failed” and “infrequently failed” tires in the country. The results showed that the dimensions of almost all the tested tires were somewhat different from those documented in the SASO standards. On the other hand, all the tested tires passed the bead unseating and strength tests. All tires in the “frequently failed” category failed the tensile strength test. In contrast, all tires from the “infrequently failed” category passed this test. The average values of the test for these two tire categories were statistically different at a 95% confidence level.
Experimental Investigation of an Indirect Evaporative Cooler Consisting of a Heat Pipe Embedded in Porous Ceramic
Authors: Riffat S. , Zhu J.
Published: May 2017

An indirect evaporative cooler incorporating a porous ceramic and a heat pipe was described. Experiments were carried out to examine the effects of various ceramic properties, such as porosity, wall thickness, and outside diameter. Use of the cooler for a chilled ceiling in an environmental chamber was also investigated.Atemperature drop of 3.8oC per square metre of ceramic surface area was achieved for an 18 m chamber.
Facility Location for Solid Waste Management through Compilation and Multicriterial Ranking of Optimal Decentralised Scenarios: A Case Study for the Region of Peloponesse in Southern Greece
Authors: Karagiannidis A. , Perkoulidis G. , Moussiopoulos N. , Chrysochoou M.
Published: May 2017

The present paper addresses the problem of locating solid waste management facilities.Specifically, it studies and proposes optimal alternative solutions for the Greek Region of Peloponnese,by examining facilities for transferring, sorting, treating and landfilling of wastes. Quantitative and qualitative databases concerning the current solid waste management at the Region have been created and used by the model. A customized mixed-integer linear network model has been developed and solved for various evaluation criteria on a single-criterion basis by the use of a location-allocation modeling framework.The solutions resulting from the parametrical application of the multicriterial method ELECTRE III are then ranked for the entire criteria-spectrum. The best alternative scenario is presented for the Region in accordance with current legislation on waste management, which maximizes environmental benefits and promotes recycling, in the frame of sustainable waste management.
Operator Performance and Satisfaction in an Ergonomically Designed Assembly Workstation
Authors: Shikdar A.A. , Al-Hadhrami M.A.
Published: May 2017

The objective of this study was to investigate the effects on operator performance and satisfaction of an ergonomically designed workstation for performing a repetitive industrial assembly task. Experiments were conducted in a company with industrial workers using existing and newly developed workstations. Operator performance on the ergonomically designed workstation was 27% higher compared to the existing non-ergonomically designed workstation. Worker satisfaction score was also improved by 41% in the ergonomically designed workstation condition. The new workstation for a repetitive assembly task had highly significant positive effect on worker performance and satisfaction. Special features of the ergonomically designed assembly workstation were an adjustable and adequate worktable, an adjustable and ergonomically designed chair, ergonomically designed hand tools and a systematic layout of the workstation components.
Generalized Model for Spectral Efficiency of Cellular Systems
Authors: Abbosh A.M.
Published: May 2017

A general mathematical model was used to study the spectral efficiency of cellular systems. The model took into consideration effects of first and second tier interference. The random distribution of users across the whole area covered by the cellular system as well as the shadowing and multipath effects were taken into account. The influence of sectorization on value of the spectral efficiency was also studied. The model investigated the effects of the cell radius and cluster size on the spectral efficiency. The influence of different propagation conditions on the spectral efficiency was also considered. Results of simulation showed that an improvement of up to 70% can be achieved in the spectral efficiency, when using a six-sector system in comparison with the omni-directional system. Also, the spectral efficiency was shown to decay by a rate proportional to the square of the radius. It was also shown that spectral efficiency improved in severe propagation conditions. Using a higher value for the cluster size decreased the spectral efficiency by a rate proportional to the square root of the cluster size.
Effects of Pavement Skid Resistance on Traffic Accidents
Authors: Al-Mansour Abdullah I.
Published: May 2017

The Ministry of Transport (MOT) in the Kingdom of Saudi Arabia had collected a massive amount of friction measurements using a Mu-meter covering most of the major highway network in the kingdom. Traffic accident data of 89 high accident rate locations from four main different highway classes were extracted from the MOT accident records. Pavement skid resistance for the selected locations was determined from the pavement skid resistance records. The objective of this paper is to utilize these data to investigate the effects of pavement skid resistance on traffic accidents. The analysis included establishing relationships between skid resistance and accident number, accident significance and accident density. It was determined that a decreasing skid resistance leads to an increase in traffic accidents. Acritical value of skid resistance was also established based on number, significance and density of accidents.
Travel Characteristics of Female Students to Colleges in the Kingdom of Saudi Arabia
Authors: Al-Ahmadi H.M.
Published: May 2017

This study is focused on the problems faced by female students residing in the Kingdom of Saudi Arabia. Many of these female students live far from their colleges and they have to travel from villages to cities in order to obtain a university degree. In so doing they travel long distances everyday using various modes of transport. As they are not permitted to drive, these students depend on male drivers to take them to their colleges. The aim of this study was to investigate and identify problems associated with such modes of transport. Results show that most students experience some problems and encounter disproportionate levels of hardship. The findings were based on a survey carried out in the Kingdom and was distributed to representative sample of female students. This paper includes a detailed analysis of the data from which a number of conclusions and recommendations were made. The conclusions suggested that the travel situation encountered by female students who travel by passenger car could be improved in terms of time, cost and convenience. Thirteen percent of female students rated the vehicles they used to be in unacceptable condition for traveling while 6% marked the drivers as not violating traffic rules, and the majority (53%) was captives to their current mode of transportation.
Numerical Modeling of Foam Drilling Hydraulics
Authors: Baris Ozcan , Ayala Luis , Watson Robert W.
Published: May 2017

The use of foam as a drilling fluid was developed to meet a special set of conditions under which other common drilling fluids had failed. Foam drilling is defined as the process of making boreholes by utilizing foam as the circulating fluid. When compared with conventional drilling, underbalanced or foam drilling has several advantages. These advantages include: avoidance of lost circulation problems, minimizing damage to pay zones, higher penetration rates and bit life. Foams are usually characterized by the quality, the ratio of the volume of gas, and the total foam volume. Obtaining dependable pressure profiles for aerated (gasified) fluids and foam is more difficult than for single phase fluids, since in the former ones the drilling mud contains a gas phase that is entrained within the fluid system. The primary goal of this study is to expand the knowledge-base of the hydrodynamic phenomena that occur in a foam drilling operation. In order to gain a better understanding of foam drilling operations, a hydrodynamic model is developed and run at different operating conditions. For this purpose, the flow of foam through the drilling system is modeled by invoking the basic principles of continuum mechanics and thermodynamics. The model was designed to allow gas and liquid flow at desired volumetric flow rates through the drillstring and annulus. Parametric studies are conducted in order to identify the most influential variables in the hydrodynamic modeling of foam flow.
Compressive Strength and Surface Absorption of High Strength Silica Fume Concrete Under Different Curing Conditions
Authors: Al-Oraimi S.K. , Hago A.W. , Hassan H.F. , Taha R.
Published: May 2017

The effect of curing conditions and silica fume replacement on the compressive strength and the initial surface absorption of high performance concrete is reported. The silica fume contents were 5, 10, 15 and 20%, by weight of cement. Four different curing conditions were used: air curing, control curing and two other curing conditions recommended by BS8110 and ACI308-81. The cementitious material (binder) content was constant (400 kg/m3); the water/cement (w/c) ratio was also maintained at a constant value of 0.35; while the water/binder (w/b) ratio ranged from 0.35 to 0.28. The addition of silica fume enhanced the compressive strength significantly up to 30%. The 28-day compressive strength was found to be 69.9 MPa without silica fume and it was determined to be 89.9 MPa with silica fume under the standard curing condition. The 28-day compressive strength results under the control curing condition were found to be higher than the compressive strength for specimens cured under other curing conditions. The surface absorption (ml/m2.s) was found to decrease as the percentage replacement of silica fume was increased. Control curing also decreases the surface absorption of water compared with air curing. Concrete with silica fume was less sensitive to drying than that without silica fume.
Analytical Modelling and Simulation of Photovoltaic Panels and Arrays
Authors: Bourdoucen H. , Gastli A.
Published: May 2017

In this paper, an analytical model for PV panels and arrays based on extracted physical parameters of solar cells is developed. The proposed model has the advantage of simplifying mathematical modelling for different configurations of cells and panels without losing efficiency of PV system operation. The effects of external parameters, mainly temperature and solar irradiance have been considered in the modelling. Due to their critical effects on the operation of the panel, effects of series and shunt resistances were also studied. The developed analytical model has been easily implemented, simulated and validated using both Spice and Matlab packages for different series and parallel configurations of cells and panels. The results obtained with these two programs are in total agreement, which make the proposed model very useful for researchers and designers for quick and accurate sizing of PV panels and arrays.
Performance of TETRA and GSM\GPRS as a Platform for Broadband Internet and Multimedia Evolution
Authors: Dababneh M. I. , Al-Khawaldeh E. S.
Published: May 2017

In this paper, a novel approach for the comparison between TETRA system and other contenders is presented showing the relative potentials, thence applications and possible new services. TETRA Voice plus Data (V+D) and GPRSbased- GSM performance are also compared for defined multimedia transmission to revise the capability of bothsystems to afford multimedia applications to large number of subscribers with the shortest time possible while maintaining the optimal channel utilization. Performance measurements for data transmission illustrate that TETRA exhibits faster time response for connection setup time than the GPRS\GSM applications can provide. Simulation results also confirm that TETRA can support larger number of Mobile Stations (MSs) than the GSM\GPRS for the same time delay period, yet TETRA requires minimal network resources in comparison with GSM\GPRS for the same supported service. Indeed this is important in the present time where the demand on wireless communication is increasing dramatically and this what stimulates the concept of this research. Also, the hypothesis that certain communications systems utilizes spectrum efficiency more effectively than others and the fact that radio spectrum is a scarce recourse have further encourages the start of this research.
Biosorption of Zinc on Immobilized Green Algae: Equilibrium and Dynamics Studies
Authors: Sheikha D. , Ashour I. , Abu Al-Rub F.A.
Published: May 2017

The efficacy of using blank alginate beads and immobilized dead algal cells for the removal of zinc ions from aqueous solutions was investigated. It was found that the sorption capacities were significantly affected by solution pH; with higher pH favoring higher zinc ion uptake. Dynamics and isotherm experiments were carried out at the optimal pH 5.0. Zinc uptake on either sorbent was found to be rapid where approximately 90% of the maximum zinc uptake occurred within the first 30 min in both cases of blank alginate and immobilized algal cells. The equilibrium data for the biosorption of zinc ions onto both sorbents were fitted to the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm equations. The presence of copper and nickel in aqueous solutions was found to suppress the sorption process. The results of the dynamics studies revealed that the biosorption of zinc on immobilized dead algal cells followed pseudo-second order kinetics with little intraparticle diffusion mechanism contribution.
Broadband Vibration Attenuation Using Hybrid Periodic Rods
Authors: Asiri S.
Published: May 2017

This paper presents both theoretically and experimentally a new kind of a broadband vibration isolator. It is a table-like system formed by four parallel hybrid periodic rods connected between two plates. The rods consist of an assembly of periodic cells, each cell being composed of a short rod and piezoelectric inserts. By actively controlling the piezoelectric elements, it is shown that the periodic rods can efficiently attenuate the propagation of vibration from the upper plate to the lower one within critical frequency bands and consequently minimize the effects of transmission of undesirable vibration and sound radiation. In such a system, longitudinal waves can propagate from the vibration source in the upper plate to the lower one along the rods only within specific frequency bands called the "Pass Bands" and wave propagation is efficiently attenuated within other frequency bands called the "Stop Bands". The spectral width of these bands can be tuned according to the nature of the external excitation. The theory governing the operation of this class of vibration isolator is presented and their tunable filtering characteristics are demonstrated experimentally as functions of their design parameters. This concept can be employed in many applications to control the wave propagation and the force transmission of longitudinal vibrations both in the spectral and spatial domains in an attempt to stop/attenuate the propagation of undesirable disturbances.
Tuning of SVC Stabilizers over a Wide Range of Load Parameters Using Pole-Placement Technique
Authors: Ellithy K.
Published: May 2017

This paper investigates the effect of typical load model parameters on the static var compensator (SVC) stabilizers tuning. A proportional-Integral (PI) type stabilizer is considered and its gain-settings are tuned using the pole-placement technique to improve the damping of power systems. Tuning of SVC stabilizers (damping controllers) traditionally assumes that the system loads are voltage dependent with fixed parameters. However, the load parameters are generally uncertain. This uncertain behavior of the load parameters can de-tune the gains of the stabilizer; consequently the SVC stabilizer with fixed gain-settings can be adequate for some load parameters but contrarily can reduce system damping and contribute to system instability with loads having other parameters. The effect of typical load model parameters on the tuning gains of the SVC PI stabilizer is examined and it is found the load parameters have a considerable influence on the tuning gains. The time domain simulations performed on the system show that the SVC stabilizer tuned at fixed load parameters reduce the system damping under other load parameters and could lead system instability.
Fog and Rain Water Collection from Trees in the Dhofar Region in the Sultanate of Oman
Authors: Abdul-Wahab S. A. , Al-Hinai H. , Al-Najar K. A. , Al-Kalbani M. S.
Published: May 2017

This work had two purposes. The first was to measure and investigate the amount of fog and rain water collected by a sample of trees during the summer monsoon season in the mountains of the Dhofar region in the south of Oman. The second purpose was to assess the potential of trees with different leaf shapes, sizes and cross sectional canopy areas to collect fog and rain water in the area. In order to meet these purposes three different tree species, were selected for experimental investigation and field measurements. They included fig, lemon, and tamarind trees. The experiments were designed and implemented in the monsoon season of 2006, between the 13th of July and the 3rd of September. The daily measurements of water collection showed that the three species of tree have different water collection capacities. It was found that the fig tree collected the least water. The fog water collection of the fig tree over a period of 47 days between the 13th of July and the 3rd of September was 140.5 L/m2, or an average of 2.7 L/m2/d. The fog water collection of the lemon tree was 243.0 L/m2, or an average of 4.4 L/m2/d. In terms of potential collection of the tamarind tree, the results showed that it collected a fog water of 218.9 L/m2, or an average of 4.3 L/m2/d over the same period. The study contributes to the knowledge of how different tree species collect fog and rain water, and concludes with a set of recommendations.
Dynamic Mechanical Moduli of Residual Softwood-Filled Polystyrene
Authors: Abdel-Goad Mahmoud
Published: May 2017

Residual softwood sawdust (RSS) was added to polystyrene (PS) that has molecular weight 280000 g/mol. The PS composite was prepared by melt mixing technique. The dynamic mechanical tests are carried out using ARES-rheometer (Rheometric Scientific, USA) in the dynamic mode and parallel plate geometry with diameter 25 mm. The measurements were performed at temperatures ranging from 140 to 240°C and frequencies varied from 0.1 to 100 rad/s at strain 1% and gap setting 2 mm. The dynamic mechanical properties in terms of complex modulus, G*, torque, compliance moduli, loss tangent and complex viscosity has been studied for fiber-filled PS composite. The viscoelastic properties of the filled and unfilled systems have been compared. These properties are found to be improved by the addition of RSS. The dynamic mechanical moduli and viscosity were found to rise with fiber loading.
Uptake of Cd(II) Using Natural Zeolite: Batch and Continuous Fixed-Bed Studies
Authors: LMarashdeh Luna M. , Al-Haj-Ali Ahmad M.
Published: May 2017

Uptake of Cd(II) ions by natural phillipsite tuff was investigated both in shake-flask and fixed-bed columns. Equilibrium uptake, qe, was found to best fit Langmuir adsorption isotherm with a maximum value of 25.78 mg/g. Percent removal of Cd ions was close to 100% from initial metal ion concentrations in the range 50 - 75 mg/L at 5.0 g zeolite/L. Also, qe was found to vary exponentially with zeolite dose. Break points as high as 350 minutes were obtained from bed treatment at favorable conditions of a low solution flow rate and high bed depth. In batch experiments, equilibrium pH increased to < 8.0 excluding chemical precipitation as part of the removal while in fixed-beds the final pH exceeded 9.0. It is suggested that a sieve action of zeolite porous structure plays a role as an uptake mechanism in addition to the ion exchange.
A Corrective Strategy to Alleviate Overloading in Transmission Lines Based on Particle Swarm Optimization Method
Authors: Maharana Manoj Kumar , Shanti Swarup K.
Published: May 2017

This paper presents novel corrective control actions to alleviate overloads in transmission lines by the Particle Swarm Optimization (PSO) method. Generator rescheduling and/or load shedding is performed locally, to restore the system from abnormal to normal operating state. The appropriate identification of generators and load buses to perform the corrective control action is an important task for the operators. Anew Direct Acyclic Graph (DAG) technique for selection of participating generators and buses with respect to a contingency is presented. The effectiveness of the proposed approach is demonstrated with the help of the IEEE 30 bus system. The result shows that the proposed approach is computationally fast, reliable and efficient, in restoring the system to normal state after a contingency with minimal control actions.
Multi-Objective Optimization of Submerged Arc Welding Process
Authors: Datta Saurav , Mahapatra Siba Sankar
Published: May 2017

Submerged arc welding (SAW) is an important metal fabrication technology specially applied to join metals of large thickness in a single pass. In order to obtain an efficient joint, several process parameters of SAW need to be studied and precisely selected to improve weld quality. Many methodologies were proposed in the past research to address this issue. However, a good number of past work seeks to optimize SAWprocess parameters with a single response only. In practical situations, not only is the influence of process parameters and their interactive effects on output responses are to be critically examined but also an attempt is to be made to optimize more than one response, simultaneously. To this end, the present study considers four process control parameters viz. voltage (OCV), wire feed rate, traverse speed and electrode stick-out. The selected weld quality characteristics related to features of bead geometry are depth of penetration, reinforcement and bead width. In the present reporting, an integrated approach capable of solving the simultaneous optimization of multi-quality responses in SAW was suggested. In the proposed approach, the responses were transformed into their individual desirability values by selecting appropriate desirability function. Assuming equal importance for all responses, these individual desirability values were aggregated to calculate the overall desirability values. Quadratic Response Surface Methodology (RSM) was applied to establish a mathematical model representing overall desirability as a function involving linear, quadratic and interaction effect of process control parameters. This model was optimized finally within the experimental domain using PSO (Particle Swarm Optimization) algorithm. A confirmatory test showed a satisfactory result. A detailed methodology of RSM, desirability function (DF) and a PSO-based optimization approach was illustrated in the paper.
A General Model for Describing the Performance of Brushless Doubly-Fed Induction Machines
Authors: Allam S. M. , Azmy A. M. , El-Khazendar M. A.
Published: May 2017

This paper presents a generalized model, by which the dynamic and steady-state behaviour of the Brushless Doubly-Fed Induction Machine (BDFIM) can be precisely predicted. The investigated doubly-fed machine has two sets of three-phase stator windings with different pole numbers. The rotor is a squirrel-cage type with a simple modification in order to support the two air-gap rotating fields that are produced by the stator windings and have different pole numbers. The machine model is derived in the qdo-axis variables. The qdoaxes are attached to rotor and hence, it rotates at the rotor speed (
Performance Comparison of Adaptive Estimation Techniques for Power System Small-Signal Stability Assessment
Authors: Feilat E. A.
Published: May 2017

This paper demonstrates the assessment of the small-signal stability of a single-machine infinite- bus power system under widely varying loading conditions using the concept of synchronizing and damping torques coefficients. The coefficients are calculated from the time responses of the rotor angle, speed, and torque of the synchronous generator. Three adaptive computation algorithms including Kalman filtering, Adaline, and recursive least squares have been compared to estimate the synchronizing and damping torque coefficients. The steady-state performance of the three adaptive techniques is compared with the conventional static least squares technique by conducting computer simulations at different loading conditions. The algorithms are compared to each other in terms of speed of convergence and accuracy. The recursive least squares estimation offers several advantages including significant reduction in computing time and computational complexity. The tendency of an unsupplemented static exciter to degrade the system damping for medium and heavy loading is verified. Consequently, a power system stabilizer whose parameters are adjusted to compensate for variations in the system loading is designed using phase compensation method. The effectiveness of the stabilizer in enhancing the dynamic stability over wide range of operating conditions is verified through the calculation of the synchronizing and damping torque coefficients using recursive least square technique.
ZigBee-Based Telemetry System
Authors: Khriji L. , Touati F. , Hamza N.
Published: May 2017

Nowadays, there is a significant improvement in technology regarding healthcare. Real-time monitoring systems improve the quality of life of patients as well as the performance of hospitals and healthcare centers. In this paper, we present an implementation of a designed framework of a telemetry system using ZigBee technology for automatic and real-time monitoring of Biomedical signals. These signals are collected and processed using 2-tiered subsystems. The first subsystem is the mobile device which is carried on the body and runs a number of biosensors. The second subsystem performs further processing by a local base station using the raw data which is transmitted on-request by the mobile device. The processed data as well as its analysis are then continuously monitored and diagnosed through a human-machine interface. The system should possess low power consumption, low cost and advanced configuration possibilities. This paper accelerates the digital convergence age through continual research and development of technologies related to healthcare.