The new method proposed is based on the formation of hydralazine-Bromophenol blue ion pair simply and without further extraction or heating. The ion pair was prepared in the presence of pH 3 citrate buffer forming a y...The new method proposed is based on the formation of hydralazine-Bromophenol blue ion pair simply and without further extraction or heating. The ion pair was prepared in the presence of pH 3 citrate buffer forming a yellow-colored chromogen. A new maximum UV-visible band formed at 416 nm. The color was stable for more than 10 hours and obeyed Beer’s Law over the concentration range of 10 - 50 µg/mL. The calculated molar absorptivity and Sandell’s sensitivity were 1.01 × 104 L∙mol−1∙cm−1 and 0.0514 µg/mL, respectively. The elements of method validation stipulated by The International Conference on Harmonization [Q2 (R1)] were applied for hydralazine hydrochloride assay in pure and pharmaceutical tablet formulation. The average recoveries of the pure solution and the pharmaceutical formulation were 98.94% and 99.50%, respectively. The results were statistically compared by F-test, which indicates that the method can be precise and repeatable for both pure and pharmaceutical solutions. The method was found to be accurate, reproducible, and cost-effective, and validated for the assay of hydralazine in terms of the routine quality control.展开更多
As the internet traffic along with the processing power in data centers are exponentially growing, the need for the design of energy efficient with highly elastic networking infrastructure to support the different app...As the internet traffic along with the processing power in data centers are exponentially growing, the need for the design of energy efficient with highly elastic networking infrastructure to support the different applications and cloud services that can be hosted in data centers have become a hot research area. A key departure from the norm is that conventional routers and switches in conventional data centers are replaced with high performance Passive Optical Networks (PONs) to take over the role of routing and traffic forwarding through efficient resource provisioning algorithms. In this paper, the different aspects of PONs in the design of energy efficient, high capacity, and highly elastic networking infrastructures to support the applications and services hosted by modern data centers are considered. In this work, a mathematical optimization model for energy-efficient and delay-minimized scheduling in AWGR based PON data center for PON cell fabric configuration will be presented. The performance of the proposed architecture in terms of efficient scheduling against average delay and power consumption for different traffic loads and patterns will be evaluated. Different scenarios of traffic;random and unbalanced with hotspots are examined to evaluate the average delay and power consumption with and without sleep mode. Results have shown that with sleep mode enabled, power savings for two evaluated objective functions have shown similar results when examining different traffic patterns. The power savings range between 8% and 55% during low and high load activities, respectively. However, minimization of delay model has shown improvement in reducing total average delay reaching up to 42% if compared with the model with objective of minimization of power consumption.展开更多
In this study, we will cover the basic methods used to distinguish between inrush current and fault current in power transformers. First, the nature of inrush current is presented compared to the fault current. Then t...In this study, we will cover the basic methods used to distinguish between inrush current and fault current in power transformers. First, the nature of inrush current is presented compared to the fault current. Then the nature of the magnetizing current due to energizing a power transformer at no-load is explained. The first generation of methods used to disable the protective relay system during inrush current, namely the Desensitizing and Tripping Suppressor, is introduced. The second generation, the harmonic restraint method and the waveform-based restraint method with their different versions, is explained. Then we will explore thoroughly the fictitious equivalent resistance method as an example of the third generation of model type restraining or blocking methods. Finally, a comparison between these methods and conclusion is carried out.展开更多
The growing demands for high speed connectivity to keep pace with bandwidth intensive applications and services have spawned the idea of developing PONs with capabilities beyond those of copper and wireless-based tech...The growing demands for high speed connectivity to keep pace with bandwidth intensive applications and services have spawned the idea of developing PONs with capabilities beyond those of copper and wireless-based technologies in access network. In this article, an approach for the design of an energy efficient bandwidth allocation mechanism for the shared upstream communication link in the Fiber to the Home (FTTH) access network is presented and evaluated using Mixed Integer Linear Programming (MILP) model. In the MILP model, two objective functions for minimization of power consumption and minimization of blocking were evaluated. The results have shown that with the objective of power minimization approach, Optical Network Terminals (ONTs) are efficiently grouped to the minimum number of active networking Optical Line Terminal (OLT) switches, traffic is groomed, ports are efficiently utilized, and hence total power consumption is minimized. Results have shown that with energy efficient bandwidth allocation approach consideration, energy savings can reach up to 80% for different examined traffic loads following uniform distribution.展开更多
Seawater desalination is one of the major industrial activities along the coastline of Kuwait that poses profound environmental impact on the quality of seawater.This study focuses on investigating the potential conta...Seawater desalination is one of the major industrial activities along the coastline of Kuwait that poses profound environmental impact on the quality of seawater.This study focuses on investigating the potential contamination of biocides,volatile organic hydrocarbons(VOCs)and other halogenated hydrocarbons discharged from Az-Zour desalination plant.Chemical contamination by residual chlorine(RC)and some VOCs was detected in effluents from inside and at the vicinity of the plant.RC ranged between 0.15 and 0.49 mg/L while bromoform(CHBr3)was the highest of all the VOCs detected and ranged between 0.22 and 3.30μg/L.Benzinoides(benzene,toluene,xylene and ethylbenzene)were also detected at 0.1μg/L and 0.25μg/L.The levels of RC as measured in the vicinity of the Az-Zour plant are below the limit set up by Kuwait EPA.However,it still poses effects to the nearby aquatic life and therefore,it is important to lower the concentration of RC in the discharge effluent.展开更多
This paper reviews the machinability and mechanical properties of natural fiber-reinforced composites. Coupling agents, operating parameters, as well as chemical treatment effects on natural fiber-reinforced composite...This paper reviews the machinability and mechanical properties of natural fiber-reinforced composites. Coupling agents, operating parameters, as well as chemical treatment effects on natural fiber-reinforced composites’ machinability are also reviewed. Moreover, the impacts of fibers’ physical properties on the machinability of the composite are mentioned. Fiber volume fraction (V<sub>f</sub>), fiber orientation as well as chemical treatment effects on mechanical properties are also defined. Conclusively, the effect of fibers’ physical properties as well as mechanical properties is described. It was discovered that chemical treatment of natural fibers improved their compatibility with the matrix by removing their surface tissues, increasing the roughness average (Ra), and reducing moisture absorption. Also, the Orientation of the fiber plays an important role in controlling the mechanical properties of the composite. Moreover, some physical properties of the fibers, including quality of fiber distributed in the matrix;fiber size, length, and diameter;moisture absorption;porosity and the way fibers break during compounding with the matrix, were found to affect the mechanical properties of the composites formed.展开更多
This research aims to develop a model to enhance lymphatic diseases diagnosis by the use of random forest ensemble machine-learning method trained with a simple sampling scheme. This study has been carried out in two ...This research aims to develop a model to enhance lymphatic diseases diagnosis by the use of random forest ensemble machine-learning method trained with a simple sampling scheme. This study has been carried out in two major phases: feature selection and classification. In the first stage, a number of discriminative features out of 18 were selected using PSO and several feature selection techniques to reduce the features dimension. In the second stage, we applied the random forest ensemble classification scheme to diagnose lymphatic diseases. While making experiments with the selected features, we used original and resampled distributions of the dataset to train random forest classifier. Experimental results demonstrate that the proposed method achieves a remark-able improvement in classification accuracy rate.展开更多
Presence of different terms with various values can alter the thermal behavior of the nanofluids flow over porous surfaces.The aim of this research is to study the influence of nanoparticles volume fraction,nanopartic...Presence of different terms with various values can alter the thermal behavior of the nanofluids flow over porous surfaces.The aim of this research is to study the influence of nanoparticles volume fraction,nanoparticles type,suction or injection,the heat generation or absorption,the Eckert number,thermal and velocity slip parameters,and radiation on the velocity and temperature fields on the flow and heat transfer over a porous flat plate.Four different types of nanoparticles including metal nanoparticles (Cu),metal oxide nanoparticles (Al2O3) and carbon-based nanomaterials (MWCNTs and SWCNTs) which were dispersed in the water (as based fluid) are studied.The governing equations are converted into the ordinary differential equations using similarity solution and solved numerically by the RKF45 algorithm.The results of the simulations showed a contradiction with the results of other researchers who expressed that using nanoparticles with higher thermal conductivity and volume fraction led to increasing heat transfer rate in nanofluids;this study proves that,in some cases,boosting the volume fraction of nanoparticles has a potential to decrease the heat transfer rate due to significant changes in values of some parameters including radiation,heat generation,and viscous dissipation.展开更多
Objective:To analyze scrum leptin levels in patients with malaria falciparum and compare them with healthy controls and correlate with development and outcome of malaria infection.Methods:Sixty cases of malaria falcip...Objective:To analyze scrum leptin levels in patients with malaria falciparum and compare them with healthy controls and correlate with development and outcome of malaria infection.Methods:Sixty cases of malaria falciparum were included in this study as patients.Thirty healthy individuals of comparable age,racial and body mass index were taken as controls.All patients were diagnosed by clinical picture and the presence of malaria parasites in blood film.Estimation of liver function test,kidney function test,complete blood count,fasting blood sugar,fasting serum insulin,pro-inflammatory cytokine tumor necrosis factor alpha(TNFα)and interleukin 1(IL1),estimation of morning serum leptin and calculation of body mass index(kg/m^2)were done in both groups on the day of admission,on discharge and 7 d after discharge.Results:At admission,leptin levels were significantly higher in patients group than in control while lasting serum insulin levels were not significantly different between the two groups.There were significant increases as regard to TNFαand IL1 in malaria patients.Significant differences were observed between the control and the patient group for leptin,TNFαand IL1 at the time of admission and discharge.After discharge for 7 d.a significant decline in scrum leptin levels,TNFαand IL1 in the patients group was observed as compared with time of admission and time of discharge,a positive correlation between serum leptin levels and TNFαand IL1.Conclusions:Leptin hormone level might play an important role in development and outcome of malaria infection.展开更多
A numerical study based on the finite volume method has been performed to study the three-dimension natural convection in a parallelogrammic top side opened cavity filled nanofluid with partially heated square at the ...A numerical study based on the finite volume method has been performed to study the three-dimension natural convection in a parallelogrammic top side opened cavity filled nanofluid with partially heated square at the bottom side.Results are obtained for different governing parameters such as nanoparticle concentration (φ) from 0 to 0.05,inclination angle of the back and front walls (α) from 5° to 75°,Rayleigh number from 10^3 to 10^5,and length of heater changer from 0.1 to 1.The main finding from the obtained result showed that the inclination angle and nanoparticle volume fraction affect the flow structure and enhance the heat transfer.展开更多
Seawater desalination has become the only viable source of fresh water for Kuwait.However,desalination plants could have several impacts on the surrounding marine environment.The major concern of these impacts surroun...Seawater desalination has become the only viable source of fresh water for Kuwait.However,desalination plants could have several impacts on the surrounding marine environment.The major concern of these impacts surrounds the outfall effluent discharge because of its physical and chemical features including high temperature and salinity associated with residual chemicals used in the pretreatment process.In this study assessment of potential impact of Az-Zour desalination plant discharge effluent on marine environment was carried out.The assessment consisted of field measurements and numerical modelling of effluent dispersion.The results revealed a potential impact by temperature and salinity between 4 and 6 oC and 2-4 ppt above ambient and mean levels for Kuwait seawater.The predictions of hydrodynamic modelling show that the plume from the outfall runs parallel to the shoreline and the influenced area can reach to about 40 km^2.展开更多
In this paper, a numerical study of natural convection in a square enclosure with non-uniform temperature distribution maintained at the bottom wall and filled with nanofluids is carried out using different types of n...In this paper, a numerical study of natural convection in a square enclosure with non-uniform temperature distribution maintained at the bottom wall and filled with nanofluids is carried out using different types of nanoparticles. The remaining walls of the enclosure are kept at a lower temperature. Calculations are performed for Rayleigh numbers in the range 5 × 103 ≤ Ra ≤ 106 and different solid volume fraction of nanoparticles 0 ≤ χ ≤ 0.2. An enhancement in heat transfer rate is observed with the increase of nanoparticles volume fraction for the whole range of Rayleigh numbers. It is also observed that the heat transfer enhancement strongly depends on the type of nanofluids. For Ra = 106, the pure water flow becomes unsteady. It is observed that the increase of the volume fraction of nanoparticles makes the flow return to steady state.展开更多
This paper presents a robust adaptive control scheme for a class of continuous-time linear systems with unknown non-smooth asymmetrical deadzone nonlinearity at the input of the plant. The methodology is applied to ha...This paper presents a robust adaptive control scheme for a class of continuous-time linear systems with unknown non-smooth asymmetrical deadzone nonlinearity at the input of the plant. The methodology is applied to handle input deadzone as well as unmeasurable disturbances simultaneously in strictly matched systems. The proposed controller robustly cancels any residual distortion caused by the inaccurate deadzone cancellation scheme. The scheme is shown to successfully cancel the deadzone’s deleterious effect as well as eliminate other unmeasurable disturbances within the span of the input. The new controller ensures the global stability of all states and adaptations, and achieves asymptotic tracking. The asymptotic stability of the closed-loop system is proven by Lyapunov arguments, and simulation results confirm the efficacy of the control methodology.展开更多
Variations in phytogeography of Jal Al-Zor wadi system in Sabah Al Ahmad Nature Reserve, an arid national park in Kuwait, in relation to physiographic and edaphic conditions were investigated using alpha diversity and...Variations in phytogeography of Jal Al-Zor wadi system in Sabah Al Ahmad Nature Reserve, an arid national park in Kuwait, in relation to physiographic and edaphic conditions were investigated using alpha diversity and multivariate analyses. A total of 66 plant species were recorded at low-relief and high-relief wadis. Altitude and slope gradients, grain size distribution and soil texture properties had a significant relationship with plant cover and plant diversity. There was a high diversity of life-forms along the wadi system with a dominant of therophytes(annuals) particularly in spring after winter rainfalls. Chamaephytes and hemicryptophytes were the dominant perennial life-forms. A chorological analysis documents the strong effect of Saharo-Arabian chorotype on the vegetation of the study area. Cluster analysis clarified eight vegetation assemblages along altitude and slope gradients within the wadi system. Alpha diversity of plant species was greater in plant assemblages at low-relief wadis than at high-relief wadis. Vegetation structure in this study showed that phytogeographically, wadis of Jal Al-Zor were closely related to the wadis in the Arabian deserts. The slope gradient pattern and edaphic conditions of plant assemblages and plant diversity in the conserved wadis of Jal Al-Zor may be suggested as a reference model for restoration strategy of disturbed low elevated wadis in the surrounding desert regions.Restoration would include propagation of suitable plants such as Stipagrostis plumosa-Haloxylon salicornicum-Rhanterium epapposum.展开更多
Properly created and securely communicated,non-disclosure agreement(NDA)can resolve most of the common disputes related to outsourcing of offshore software maintenance(OSMO).Occasionally,these NDAs are in the form of ...Properly created and securely communicated,non-disclosure agreement(NDA)can resolve most of the common disputes related to outsourcing of offshore software maintenance(OSMO).Occasionally,these NDAs are in the form of images.Since the work is done offshore,these agreements or images must be shared through the Internet or stored over the cloud.The breach of privacy,on the other hand,is a potential threat for the image owners as both the Internet and cloud servers are not void of danger.This article proposes a novel algorithm for securing the NDAs in the form of images.As an agreement is signed between the two parties,it will be encrypted before sending to the cloud server or travelling through the public network,the Internet.As the image is input to the algorithm,its pixels would be scrambled through the set of randomly generated rectangles for an arbitrary amount of time.The confusion effects have been realized through an XOR operation between the confused image,and chaotic data.Besides,5D multi-wing hyperchaotic system has been employed to spawn the chaotic vectors due to good properties of chaoticity it has.The machine experimentation and the security analysis through a comprehensive set of validation metric vividly demonstrate the robustness,defiance to the multifarious threats and the prospects for some real-world application of the proposed encryption algorithm for the NDA images.展开更多
Gas-phase thermolysis of 1-ethoxycarbonyl-benzotriazole under static, FVP and microwaves condition yielded N^1 and NZ-ethylbenzotriazole, 2-ethoxy-1,3-benzooxazole, biphenylene and oxazolidin-2-one. On the other hand,...Gas-phase thermolysis of 1-ethoxycarbonyl-benzotriazole under static, FVP and microwaves condition yielded N^1 and NZ-ethylbenzotriazole, 2-ethoxy-1,3-benzooxazole, biphenylene and oxazolidin-2-one. On the other hand, direct condensation and pyrolysis of naphtho[1,8-de][1,2,3]triazine with ethylisocyanate, phenylisocyanate and their isothiocayanates, benzoylisothiocyanate and thiourea at 150-160 ℃ or under microwaves irradiation produced the corresponding naphthopyrimidin-2-one derivatives.展开更多
There is recent trend of providing additional treatment of wastewater beyond tertiary level. The purpose is to refine water to a quality that is safe for reuse for unrestricted irrigation and other non potable uses. F...There is recent trend of providing additional treatment of wastewater beyond tertiary level. The purpose is to refine water to a quality that is safe for reuse for unrestricted irrigation and other non potable uses. For this purpose, Kuwait has built and operated an advanced wastewater treatment plant with capacity of 500,000 m3·dl. This plant providing treatment beyond tertiary utilizes the process of Ultra Filtration （UF） and Reverse Osmosis （RO）. The reject water of this unit contains high concentration of total nitrogen and total phosphate. Safe disposal of this water into the environment or possible reuse needs substantial reduction of these chemicals. In this study, a bench scale up-flow sludge blanket filtration system was investigated. The system operated with an average Hydraulic-Retention Time （HRT） of 19 h, whereas, sludge age varied within the range of 14 days to 16.5 days. The results show that the average removal efficiencies of the system for Biological Oxygen Demand （BOD）, Chemical Oxygen Demand （COD） were over 86% and 82% respectively. The phosphate and nitrogen＇s average removal were found to be 50% and 45% respectively.展开更多
Kuwait has adopted a dual system in which large-scale desalination plants are coupled to the power generation plants.These dual systems are located on the coastline and utilize huge amount of water for distillation an...Kuwait has adopted a dual system in which large-scale desalination plants are coupled to the power generation plants.These dual systems are located on the coastline and utilize huge amount of water for distillation and cooling.As a result,large volume of brine is produced which disposed back into the Gulf with an increase in temperature over the seawater ambient temperature.This brine is also loaded with chemicals used in the pretreatment stages and trace metals.The increases in desalination activities in Kuwait raise concerns over potential negative impacts on the coastal marine environment.In the study,sediment samples were collected from19stations in summer and spring seasons.The samples were analyzed for metals and hydrocarbons concentrations.The results revealed that the concentration of all analyzed metals at the vicinity of Az-zour desalination plant were relatively low and ascribed within the limits of unpolluted areas.The results also showed that the contamination by Total Petroleum Hydrocarbons(TPH)and Total Organic Carbon(TOC)in sediments from the investigated area was relatively low and did not indicate high contamination with petroleum near the plant.展开更多
Thick recent carbonate sediments cover all the intertidal and subtidal zones consist of mainly different shell and coral reef debris. The chemical investigations of the coral fragments were done on controlled bases, w...Thick recent carbonate sediments cover all the intertidal and subtidal zones consist of mainly different shell and coral reef debris. The chemical investigations of the coral fragments were done on controlled bases, which depend on the coral size and seasons, in order to elucidate the effect of weather parameters on the coral reefs. Geochemical investigation indicated that corals gathered from high-tide mark are mainly contaminated by copper, cobalt, and chromium and the corals gathered from low-tide mark are contaminated by lead and zinc. All the analyzed coral samples are contaminated by copper. The major contamination sights by heavy metals are related to the weather pattern around the islands. Calcium concentration in all the corals indicates a low-Magnesium calcite or aragonite composition, except for some coral samples which were gathered during October from the high-tide mark. Trace element concentration levels show high concentrations at sights of low-wave action around the island during the various seasons. Chemical analysis on the coral derbies indicates compositional variations regarding calcium and magnesium mole% between the seasons and at different locations and it is dependant on wind direction and water salinity. Some localities are iron rich others are aluminum and potassium rich. Generally, aluminum, iron, and potassium occur in lower quantities than the other elements. Therefore, all the chemical data regarding trace elements indicate relationship to weather and environmental parameters.展开更多
Indoor and outdoor air samples were simultaneously collected from the largest office building in Jahra City during 57 sampling events between August 2010 and November 2011. The collected samples were analyzed for 78 v...Indoor and outdoor air samples were simultaneously collected from the largest office building in Jahra City during 57 sampling events between August 2010 and November 2011. The collected samples were analyzed for 78 volatile organic compounds (VOCs) using CO2 cryogenic preconcentration and GC/MS analysis. Of the 48 VOCs detected, the toluene concentration exceeded the recommended air quality guidelines in 2% of the outdoor samples, and the benzene concentration exceeded these guidelines in 17.5% and 19.5% of the indoor and outdoor samples, respectively. Industrial and vehicle emissions were negligible. Emissions from oil fields, various crude oil production and flaring activities in the north were major sources of VOCs in the ambient air. The VOC profiles;seasonal, monthly, and weekday/weekend variations;and their effects on ozone formation potentials are discussed. The results indicate that the most abundant class of chemical compounds was oxygenated compounds, of which acetone, acetaldehyde, propanal, methanol, ethanol, and 2-propanol were the most dominant species. Propene and toluene were the most abundant species of aliphatic and aromatic hydrocarbons, respectively.展开更多
文摘The new method proposed is based on the formation of hydralazine-Bromophenol blue ion pair simply and without further extraction or heating. The ion pair was prepared in the presence of pH 3 citrate buffer forming a yellow-colored chromogen. A new maximum UV-visible band formed at 416 nm. The color was stable for more than 10 hours and obeyed Beer’s Law over the concentration range of 10 - 50 µg/mL. The calculated molar absorptivity and Sandell’s sensitivity were 1.01 × 104 L∙mol−1∙cm−1 and 0.0514 µg/mL, respectively. The elements of method validation stipulated by The International Conference on Harmonization [Q2 (R1)] were applied for hydralazine hydrochloride assay in pure and pharmaceutical tablet formulation. The average recoveries of the pure solution and the pharmaceutical formulation were 98.94% and 99.50%, respectively. The results were statistically compared by F-test, which indicates that the method can be precise and repeatable for both pure and pharmaceutical solutions. The method was found to be accurate, reproducible, and cost-effective, and validated for the assay of hydralazine in terms of the routine quality control.
文摘As the internet traffic along with the processing power in data centers are exponentially growing, the need for the design of energy efficient with highly elastic networking infrastructure to support the different applications and cloud services that can be hosted in data centers have become a hot research area. A key departure from the norm is that conventional routers and switches in conventional data centers are replaced with high performance Passive Optical Networks (PONs) to take over the role of routing and traffic forwarding through efficient resource provisioning algorithms. In this paper, the different aspects of PONs in the design of energy efficient, high capacity, and highly elastic networking infrastructures to support the applications and services hosted by modern data centers are considered. In this work, a mathematical optimization model for energy-efficient and delay-minimized scheduling in AWGR based PON data center for PON cell fabric configuration will be presented. The performance of the proposed architecture in terms of efficient scheduling against average delay and power consumption for different traffic loads and patterns will be evaluated. Different scenarios of traffic;random and unbalanced with hotspots are examined to evaluate the average delay and power consumption with and without sleep mode. Results have shown that with sleep mode enabled, power savings for two evaluated objective functions have shown similar results when examining different traffic patterns. The power savings range between 8% and 55% during low and high load activities, respectively. However, minimization of delay model has shown improvement in reducing total average delay reaching up to 42% if compared with the model with objective of minimization of power consumption.
文摘In this study, we will cover the basic methods used to distinguish between inrush current and fault current in power transformers. First, the nature of inrush current is presented compared to the fault current. Then the nature of the magnetizing current due to energizing a power transformer at no-load is explained. The first generation of methods used to disable the protective relay system during inrush current, namely the Desensitizing and Tripping Suppressor, is introduced. The second generation, the harmonic restraint method and the waveform-based restraint method with their different versions, is explained. Then we will explore thoroughly the fictitious equivalent resistance method as an example of the third generation of model type restraining or blocking methods. Finally, a comparison between these methods and conclusion is carried out.
文摘The growing demands for high speed connectivity to keep pace with bandwidth intensive applications and services have spawned the idea of developing PONs with capabilities beyond those of copper and wireless-based technologies in access network. In this article, an approach for the design of an energy efficient bandwidth allocation mechanism for the shared upstream communication link in the Fiber to the Home (FTTH) access network is presented and evaluated using Mixed Integer Linear Programming (MILP) model. In the MILP model, two objective functions for minimization of power consumption and minimization of blocking were evaluated. The results have shown that with the objective of power minimization approach, Optical Network Terminals (ONTs) are efficiently grouped to the minimum number of active networking Optical Line Terminal (OLT) switches, traffic is groomed, ports are efficiently utilized, and hence total power consumption is minimized. Results have shown that with energy efficient bandwidth allocation approach consideration, energy savings can reach up to 80% for different examined traffic loads following uniform distribution.
文摘Seawater desalination is one of the major industrial activities along the coastline of Kuwait that poses profound environmental impact on the quality of seawater.This study focuses on investigating the potential contamination of biocides,volatile organic hydrocarbons(VOCs)and other halogenated hydrocarbons discharged from Az-Zour desalination plant.Chemical contamination by residual chlorine(RC)and some VOCs was detected in effluents from inside and at the vicinity of the plant.RC ranged between 0.15 and 0.49 mg/L while bromoform(CHBr3)was the highest of all the VOCs detected and ranged between 0.22 and 3.30μg/L.Benzinoides(benzene,toluene,xylene and ethylbenzene)were also detected at 0.1μg/L and 0.25μg/L.The levels of RC as measured in the vicinity of the Az-Zour plant are below the limit set up by Kuwait EPA.However,it still poses effects to the nearby aquatic life and therefore,it is important to lower the concentration of RC in the discharge effluent.
文摘This paper reviews the machinability and mechanical properties of natural fiber-reinforced composites. Coupling agents, operating parameters, as well as chemical treatment effects on natural fiber-reinforced composites’ machinability are also reviewed. Moreover, the impacts of fibers’ physical properties on the machinability of the composite are mentioned. Fiber volume fraction (V<sub>f</sub>), fiber orientation as well as chemical treatment effects on mechanical properties are also defined. Conclusively, the effect of fibers’ physical properties as well as mechanical properties is described. It was discovered that chemical treatment of natural fibers improved their compatibility with the matrix by removing their surface tissues, increasing the roughness average (Ra), and reducing moisture absorption. Also, the Orientation of the fiber plays an important role in controlling the mechanical properties of the composite. Moreover, some physical properties of the fibers, including quality of fiber distributed in the matrix;fiber size, length, and diameter;moisture absorption;porosity and the way fibers break during compounding with the matrix, were found to affect the mechanical properties of the composites formed.
文摘This research aims to develop a model to enhance lymphatic diseases diagnosis by the use of random forest ensemble machine-learning method trained with a simple sampling scheme. This study has been carried out in two major phases: feature selection and classification. In the first stage, a number of discriminative features out of 18 were selected using PSO and several feature selection techniques to reduce the features dimension. In the second stage, we applied the random forest ensemble classification scheme to diagnose lymphatic diseases. While making experiments with the selected features, we used original and resampled distributions of the dataset to train random forest classifier. Experimental results demonstrate that the proposed method achieves a remark-able improvement in classification accuracy rate.
文摘Presence of different terms with various values can alter the thermal behavior of the nanofluids flow over porous surfaces.The aim of this research is to study the influence of nanoparticles volume fraction,nanoparticles type,suction or injection,the heat generation or absorption,the Eckert number,thermal and velocity slip parameters,and radiation on the velocity and temperature fields on the flow and heat transfer over a porous flat plate.Four different types of nanoparticles including metal nanoparticles (Cu),metal oxide nanoparticles (Al2O3) and carbon-based nanomaterials (MWCNTs and SWCNTs) which were dispersed in the water (as based fluid) are studied.The governing equations are converted into the ordinary differential equations using similarity solution and solved numerically by the RKF45 algorithm.The results of the simulations showed a contradiction with the results of other researchers who expressed that using nanoparticles with higher thermal conductivity and volume fraction led to increasing heat transfer rate in nanofluids;this study proves that,in some cases,boosting the volume fraction of nanoparticles has a potential to decrease the heat transfer rate due to significant changes in values of some parameters including radiation,heat generation,and viscous dissipation.
基金supported by College of Health Sciences(Grant No,HS-10-01)
文摘Objective:To analyze scrum leptin levels in patients with malaria falciparum and compare them with healthy controls and correlate with development and outcome of malaria infection.Methods:Sixty cases of malaria falciparum were included in this study as patients.Thirty healthy individuals of comparable age,racial and body mass index were taken as controls.All patients were diagnosed by clinical picture and the presence of malaria parasites in blood film.Estimation of liver function test,kidney function test,complete blood count,fasting blood sugar,fasting serum insulin,pro-inflammatory cytokine tumor necrosis factor alpha(TNFα)and interleukin 1(IL1),estimation of morning serum leptin and calculation of body mass index(kg/m^2)were done in both groups on the day of admission,on discharge and 7 d after discharge.Results:At admission,leptin levels were significantly higher in patients group than in control while lasting serum insulin levels were not significantly different between the two groups.There were significant increases as regard to TNFαand IL1 in malaria patients.Significant differences were observed between the control and the patient group for leptin,TNFαand IL1 at the time of admission and discharge.After discharge for 7 d.a significant decline in scrum leptin levels,TNFαand IL1 in the patients group was observed as compared with time of admission and time of discharge,a positive correlation between serum leptin levels and TNFαand IL1.Conclusions:Leptin hormone level might play an important role in development and outcome of malaria infection.
文摘A numerical study based on the finite volume method has been performed to study the three-dimension natural convection in a parallelogrammic top side opened cavity filled nanofluid with partially heated square at the bottom side.Results are obtained for different governing parameters such as nanoparticle concentration (φ) from 0 to 0.05,inclination angle of the back and front walls (α) from 5° to 75°,Rayleigh number from 10^3 to 10^5,and length of heater changer from 0.1 to 1.The main finding from the obtained result showed that the inclination angle and nanoparticle volume fraction affect the flow structure and enhance the heat transfer.
文摘Seawater desalination has become the only viable source of fresh water for Kuwait.However,desalination plants could have several impacts on the surrounding marine environment.The major concern of these impacts surrounds the outfall effluent discharge because of its physical and chemical features including high temperature and salinity associated with residual chemicals used in the pretreatment process.In this study assessment of potential impact of Az-Zour desalination plant discharge effluent on marine environment was carried out.The assessment consisted of field measurements and numerical modelling of effluent dispersion.The results revealed a potential impact by temperature and salinity between 4 and 6 oC and 2-4 ppt above ambient and mean levels for Kuwait seawater.The predictions of hydrodynamic modelling show that the plume from the outfall runs parallel to the shoreline and the influenced area can reach to about 40 km^2.
文摘In this paper, a numerical study of natural convection in a square enclosure with non-uniform temperature distribution maintained at the bottom wall and filled with nanofluids is carried out using different types of nanoparticles. The remaining walls of the enclosure are kept at a lower temperature. Calculations are performed for Rayleigh numbers in the range 5 × 103 ≤ Ra ≤ 106 and different solid volume fraction of nanoparticles 0 ≤ χ ≤ 0.2. An enhancement in heat transfer rate is observed with the increase of nanoparticles volume fraction for the whole range of Rayleigh numbers. It is also observed that the heat transfer enhancement strongly depends on the type of nanofluids. For Ra = 106, the pure water flow becomes unsteady. It is observed that the increase of the volume fraction of nanoparticles makes the flow return to steady state.
文摘This paper presents a robust adaptive control scheme for a class of continuous-time linear systems with unknown non-smooth asymmetrical deadzone nonlinearity at the input of the plant. The methodology is applied to handle input deadzone as well as unmeasurable disturbances simultaneously in strictly matched systems. The proposed controller robustly cancels any residual distortion caused by the inaccurate deadzone cancellation scheme. The scheme is shown to successfully cancel the deadzone’s deleterious effect as well as eliminate other unmeasurable disturbances within the span of the input. The new controller ensures the global stability of all states and adaptations, and achieves asymptotic tracking. The asymptotic stability of the closed-loop system is proven by Lyapunov arguments, and simulation results confirm the efficacy of the control methodology.
文摘Variations in phytogeography of Jal Al-Zor wadi system in Sabah Al Ahmad Nature Reserve, an arid national park in Kuwait, in relation to physiographic and edaphic conditions were investigated using alpha diversity and multivariate analyses. A total of 66 plant species were recorded at low-relief and high-relief wadis. Altitude and slope gradients, grain size distribution and soil texture properties had a significant relationship with plant cover and plant diversity. There was a high diversity of life-forms along the wadi system with a dominant of therophytes(annuals) particularly in spring after winter rainfalls. Chamaephytes and hemicryptophytes were the dominant perennial life-forms. A chorological analysis documents the strong effect of Saharo-Arabian chorotype on the vegetation of the study area. Cluster analysis clarified eight vegetation assemblages along altitude and slope gradients within the wadi system. Alpha diversity of plant species was greater in plant assemblages at low-relief wadis than at high-relief wadis. Vegetation structure in this study showed that phytogeographically, wadis of Jal Al-Zor were closely related to the wadis in the Arabian deserts. The slope gradient pattern and edaphic conditions of plant assemblages and plant diversity in the conserved wadis of Jal Al-Zor may be suggested as a reference model for restoration strategy of disturbed low elevated wadis in the surrounding desert regions.Restoration would include propagation of suitable plants such as Stipagrostis plumosa-Haloxylon salicornicum-Rhanterium epapposum.
基金This research is fully funded by Universiti Teknologi Malaysia under the UTM Fundamental Research Grant(UTMFR)with Cost Center No Q.K130000.2556.21H14.
文摘Properly created and securely communicated,non-disclosure agreement(NDA)can resolve most of the common disputes related to outsourcing of offshore software maintenance(OSMO).Occasionally,these NDAs are in the form of images.Since the work is done offshore,these agreements or images must be shared through the Internet or stored over the cloud.The breach of privacy,on the other hand,is a potential threat for the image owners as both the Internet and cloud servers are not void of danger.This article proposes a novel algorithm for securing the NDAs in the form of images.As an agreement is signed between the two parties,it will be encrypted before sending to the cloud server or travelling through the public network,the Internet.As the image is input to the algorithm,its pixels would be scrambled through the set of randomly generated rectangles for an arbitrary amount of time.The confusion effects have been realized through an XOR operation between the confused image,and chaotic data.Besides,5D multi-wing hyperchaotic system has been employed to spawn the chaotic vectors due to good properties of chaoticity it has.The machine experimentation and the security analysis through a comprehensive set of validation metric vividly demonstrate the robustness,defiance to the multifarious threats and the prospects for some real-world application of the proposed encryption algorithm for the NDA images.
文摘Gas-phase thermolysis of 1-ethoxycarbonyl-benzotriazole under static, FVP and microwaves condition yielded N^1 and NZ-ethylbenzotriazole, 2-ethoxy-1,3-benzooxazole, biphenylene and oxazolidin-2-one. On the other hand, direct condensation and pyrolysis of naphtho[1,8-de][1,2,3]triazine with ethylisocyanate, phenylisocyanate and their isothiocayanates, benzoylisothiocyanate and thiourea at 150-160 ℃ or under microwaves irradiation produced the corresponding naphthopyrimidin-2-one derivatives.
文摘There is recent trend of providing additional treatment of wastewater beyond tertiary level. The purpose is to refine water to a quality that is safe for reuse for unrestricted irrigation and other non potable uses. For this purpose, Kuwait has built and operated an advanced wastewater treatment plant with capacity of 500,000 m3·dl. This plant providing treatment beyond tertiary utilizes the process of Ultra Filtration （UF） and Reverse Osmosis （RO）. The reject water of this unit contains high concentration of total nitrogen and total phosphate. Safe disposal of this water into the environment or possible reuse needs substantial reduction of these chemicals. In this study, a bench scale up-flow sludge blanket filtration system was investigated. The system operated with an average Hydraulic-Retention Time （HRT） of 19 h, whereas, sludge age varied within the range of 14 days to 16.5 days. The results show that the average removal efficiencies of the system for Biological Oxygen Demand （BOD）, Chemical Oxygen Demand （COD） were over 86% and 82% respectively. The phosphate and nitrogen＇s average removal were found to be 50% and 45% respectively.
文摘Kuwait has adopted a dual system in which large-scale desalination plants are coupled to the power generation plants.These dual systems are located on the coastline and utilize huge amount of water for distillation and cooling.As a result,large volume of brine is produced which disposed back into the Gulf with an increase in temperature over the seawater ambient temperature.This brine is also loaded with chemicals used in the pretreatment stages and trace metals.The increases in desalination activities in Kuwait raise concerns over potential negative impacts on the coastal marine environment.In the study,sediment samples were collected from19stations in summer and spring seasons.The samples were analyzed for metals and hydrocarbons concentrations.The results revealed that the concentration of all analyzed metals at the vicinity of Az-zour desalination plant were relatively low and ascribed within the limits of unpolluted areas.The results also showed that the contamination by Total Petroleum Hydrocarbons(TPH)and Total Organic Carbon(TOC)in sediments from the investigated area was relatively low and did not indicate high contamination with petroleum near the plant.
文摘Thick recent carbonate sediments cover all the intertidal and subtidal zones consist of mainly different shell and coral reef debris. The chemical investigations of the coral fragments were done on controlled bases, which depend on the coral size and seasons, in order to elucidate the effect of weather parameters on the coral reefs. Geochemical investigation indicated that corals gathered from high-tide mark are mainly contaminated by copper, cobalt, and chromium and the corals gathered from low-tide mark are contaminated by lead and zinc. All the analyzed coral samples are contaminated by copper. The major contamination sights by heavy metals are related to the weather pattern around the islands. Calcium concentration in all the corals indicates a low-Magnesium calcite or aragonite composition, except for some coral samples which were gathered during October from the high-tide mark. Trace element concentration levels show high concentrations at sights of low-wave action around the island during the various seasons. Chemical analysis on the coral derbies indicates compositional variations regarding calcium and magnesium mole% between the seasons and at different locations and it is dependant on wind direction and water salinity. Some localities are iron rich others are aluminum and potassium rich. Generally, aluminum, iron, and potassium occur in lower quantities than the other elements. Therefore, all the chemical data regarding trace elements indicate relationship to weather and environmental parameters.
文摘Indoor and outdoor air samples were simultaneously collected from the largest office building in Jahra City during 57 sampling events between August 2010 and November 2011. The collected samples were analyzed for 78 volatile organic compounds (VOCs) using CO2 cryogenic preconcentration and GC/MS analysis. Of the 48 VOCs detected, the toluene concentration exceeded the recommended air quality guidelines in 2% of the outdoor samples, and the benzene concentration exceeded these guidelines in 17.5% and 19.5% of the indoor and outdoor samples, respectively. Industrial and vehicle emissions were negligible. Emissions from oil fields, various crude oil production and flaring activities in the north were major sources of VOCs in the ambient air. The VOC profiles;seasonal, monthly, and weekday/weekend variations;and their effects on ozone formation potentials are discussed. The results indicate that the most abundant class of chemical compounds was oxygenated compounds, of which acetone, acetaldehyde, propanal, methanol, ethanol, and 2-propanol were the most dominant species. Propene and toluene were the most abundant species of aliphatic and aromatic hydrocarbons, respectively.
