An-Najah Blogs :: Abu-Hilal http://blogs.najah.edu/author/haneen An-Najah Blogs :: Abu-Hilal en-us Mon, 26 Sep 2022 13:01:21 IDT Mon, 26 Sep 2022 13:01:21 IDT webmaster@najah.edu webmaster@najah.edu Experimental Energy Study for Domestic Hot Water Storage Tankshttp://blogs.najah.edu/staff/haneen/article/Experimental-Energy-Study-for-Domestic-Hot-Water-Storage-TanksPublished Articles In the last decade energy and water become the most important commodities as the world is suffering from a critical shortage in water and energy Researchers are working hard on renewable energy and energy saving In this paper an experimental study of the usable energy for domestic hot water storage tank was performed Different supply features and different flow rates have been considered To save energy in the storage tank the turbulent mixing must be eliminated In this study a cover over the supply lines was imposed It has been found that the cover for the side supply feature improves the temperature distributions in the tank For the bottom supply feature investigations indicated important improvement in the total usable hot water Approximately 17 saving in usable hot water was achieved by using a round curved cover on the bottom supply line The achieved saving in energy and hot water will help in reducing the consumed energy in residential buildings and thus keep us in a better environment Thermal Analysis of Discrete Water supply in Domestic Hot Water Storage Tankhttp://blogs.najah.edu/staff/haneen/article/Thermal-Analysis-of-Discrete-Water-supply-in-Domestic-Hot-Water-Storage-TankPublished Articles Energy and water are very important commodities to human life The world is suffering from a critical shortage in water and energy; the researchers must work hard to find sources of potable water and renewable energy Energy and water saving techniques have a great importance especially in this transmission period In this paper analyses were done for discrete water supply in hot water storage tanks aiming to reduce energy and water losses The analyses were based on an experimental study for the temperature distribution in the hot water storage tank for different flow rates and off periods 3 6 and 9 Lmin and 5 10 and 15 minutes were considered for flow rates and off periods respectively It has been found that increasing the hot water consumption rate reduces the total delivered hot water to the consumer The analyses indicated increase in the usable hot water for small and medium off periods This increase results in water and energy saving for the consumer Evaluating Thermal Performance of Solar Cookers under Jordanian Climatehttp://blogs.najah.edu/staff/haneen/article/Evaluating-Thermal-Performance-of-Solar-Cookers-under-Jordanian-ClimatePublished Articles This study presented a short review on the solar cooker designs and applications Two designs of cookers were tested The first type has a painted black base and second has internal reflecting mirrors These designs were examined under two modes of operations: at fixed position and on tracking system The cooker at a fixed position had recorded thermal efficiencies ranging from 17 to a sharp peak of 412 at the maximum solar intensity of the day around 11-12 am with an average overall efficiency around 276 Whereas cooker with internal reflecting mirrors installed on a sun tracking system gave higher water and pot temperatures and thermal efficiency ranged from 253 to 531 with an average overall efficiency around 406 Cookers installed on sun tracking system had the advantage of maintaining a higher and closer range of thermal efficiencies through the daylight than the ones at fixed positions Proposed Energy Saving Techniques for Multi-Apartment Buildingshttp://blogs.najah.edu/staff/haneen/article/Proposed-Energy-Saving-Techniques-for-Multi-Apartment-BuildingsPublished Articles During the last decade and as a result of the significant increase in the population of Jordan multi-apartment buildings became the most dominant building format especially in Amman the capital of Jordan The lack of well-developed passive heating cooling and energy saving solutions made the reliance on central heating in winter and air conditioners in summer the prominent choice for residents The sustained significant increase in the use of these high energyconsuming systems have started to exert a heavy toll on the national economy and have raised environmental and public health concerns This study is devoted to the analysis of heating and cooling problems in the new multi-apartment buildings in Jordan The main focus of this study is to minimize fuel and electricity consumption Techniques for heating and cooling are proposed This study shows that the proposed techniques will lead to significant savings in total energy consumption These savings will lead to multifold benefits including a welcomed relief to lower and middle class family budgets a significant reduction in the national reliance on imported energy and a significant reduction in greenhouse emissions Nevertheless a wider and more specific study could be done for optimizing the loads and choosing the best air conditioning system Thermal Analysis of Discrete Water Supply in Domestichttp://blogs.najah.edu/staff/haneen/article/Thermal-Analysis-of-Discrete-Water-Supply-in-DomesticPublished Articles Energy and water are very important commodities to human life The world is suffering from a critical shortage in water and energy; the researchers must work hard to find sources of potable water and renewable energy Energy and water saving techniques has a great importance especially in this transmission period In this paper analyses were done for discrete water supply in hot water storage tanks aiming to reduce energy and water losses The analyses were based on an experimental study for the temperature distribution in the hot water storage tank for different flow rates and off periods 3 6 and 9 lpm and 5 10 and 15 minutes were considered for flow rates and off periods respectively It has been found that increasing the hot water consumption rate reduces the total delivered hot water to the consumer The analyses indicated increase in the usable hot water for small and medium off periods This increase results in water and energy saving for the consumer Also optimum off periods for the different flow rates were obtained after which the total usable hot water starts decreasing as expected This optimum off period is valuable to save water and energy and can be integrated with the solar radiation in winter and summer to determine the new optimum off periods for the different locations and time Evaluating Thermal Performance of Solar Cookershttp://blogs.najah.edu/staff/haneen/article/Evaluating-Thermal-Performance-of-Solar-CookersPublished Articles This study presented a short review on the solar cooker designs and applications Two designs of cookers were tested The first type has a painted black base and second has internal reflecting mirrors These designs were examined under two modes of operations: at fixed position and on tracking system The cooker at a fixed position had recorded thermal efficiencies ranging from 17 to a sharp peak of 412 at the maximum solar intensity of the day around 11-12 am with an average overall efficiency around 276 Whereas cooker with internal reflecting mirrors installed on a sun tracking system gave higher water and pot temperatures and thermal efficiency ranged from 253 to 531 with an average overall efficiency around 406 Cookers installed on sun tracking system had the advantage of maintaining a higher and closer range of thermal efficiencies through the daylight than the ones at fixed positions Conceptual Understanding of Mass and Stiffness Fixed Points of Discrete Vibrational Systemshttp://blogs.najah.edu/staff/haneen/article/Conceptual-Understanding-of-Mass-and-Stiffness-Fixed-Points-of-Discrete-Vibrational-SystemsPublished Articles M Abu-Hilal A R Touqan The presence of mass and stiffness fixed points in the frequency responses of vibrational systems may greatly affect the design of these systems In this paper the physical reason for the occurrence of mass and stiffness fixed points and the relationship between them and the phenomenon of internal absorber are investigated It is found that the frequencies at which mass and stiffness fixed points occur represent eigenfrequencies of subsystems of the whole vibrational system Furthermore it is found that the mass and stiffness fixed points are strongly related with the phenomenon of internal absorbers Free transverse vibrations of a triple-beam systemhttp://blogs.najah.edu/staff/haneen/article/Free-transverse-vibrations-of-a-triple-beam-system-1Published ArticlesMOHAMMED ABU-HILALNABIL BEITHOU 2007 Journal of Mechanical Engineering 5830-50 In this paper the free vibration of an undamped triple-beam system on elastic foundation is analysed The system consists of three Euler-Bernoulli beams of the same length that are arranged in parallel and continuously connected by elastic layers The natural frequencies and the mode shapes of the system are determined Furthermore the initial value problem is solved to find the time-dependent free vibrations of the beams Using a numerical example the effects of the layer stiffnesses and those of the masses of the beams per unit length on the natural frequencies and the mode shapes are investigated in detail Amplification factors of beams with general boundary conditions due to a moving constant loadhttp://blogs.najah.edu/staff/haneen/article/Amplification-factors-of-beams-with-general-boundary-conditions-due-to-a-moving-constant-loadPublished ArticlesIn this paper the amplification factors of an Euler-Bernoulli beam with different boundary conditions due to a moving constant load are studied The boundary conditions considered are: pinned-pinned fixed-fixed pinned-fixed and fixed-free The effects of the beam damping and the direction of motion of the moving loads are investigated The obtained amplification factors are given in graphical form dependent on a moving speed parameter Also in addition to the amplification factors of the total response of the considered beams the amplification factors of the forced response are separately considered The present results are compared with published results where applicableDynamic response of a double Euler-Bernoulli beam due to a moving constant loadhttp://blogs.najah.edu/staff/haneen/article/Dynamic-response-of-a-double-EulerndashBernoulli-beam-due-to-a-moving-constant-loadPublished ArticlesIn this paper the dynamic response of a double-beam system traversed by a constant moving load is studied The system consists of two elastic homogeneous isotropic EulerBernoulli beams The two simply supported prismatic beams are identical parallel one upon the other and connected continuously by a viscoelastic layer The dynamic deflections of both beams are given in analytical closed forms The effects of the moving speed of the load and the damping and the elasticity of the viscoelastic layer on the dynamic responses of the beams are investigated in detail Also several plots of the deflections of the beams are given and discussed for different values of speed parameter damping ratio and stiffness parameter Furthermore the force transmitted between the beams is determined and the effects of the system parameters on this force are studied Plots of the maximum responses of the beams are presentedPerformance of a photovoltaic powered reverse-osmosis system under local climatic conditionshttp://blogs.najah.edu/staff/haneen/article/Performance-of-a-photovoltaic-powered-reverse-osmosis-system-under-local-climatic-conditionsPublished ArticlesPerformance of a photovoltaic powered reverse-osmosis system under local climatic conditions S Abdallah M Abu-Hilal M S Mohsen 2005 Desalination 183 2005 95-104 doi:101016jdesal200503030 Abstract: In addition to shortage of fresh water resources Jordan is suffering from shortages in recoverable commercial energy sources such as crude oil and natural gas The limited energy sources in Jordan makes considering renewable energy options such as solar power very attractive especially for remote areas This will be extremely important for small-scale applications Due to prevailing tough conditions such as low water quality and shortage in supplies there is a large demand for small desalination units not only in locations not connected to a water supply network but also as units for additional or independent supply In this paper an experimental study was conducted to investigate the potential of the development of water desalination using photovoltaic powered system in Jordan A testing rig was built where a reverse osmosis RO desalination system driven by photovoltaic power is used The RO unit consists of a five-micron sediment filter that is made of polypropylene two active carbon filters with 12 micrometer hole diameter and one polyamide TFC membrane The system is mechanically powered directly coupling the photovoltaic power system to a DC motor which is coupled to a pump that is capable of providing sufficient torque to run the RO system Two PV arrays are connected in series and tilted a 32_ to the south To study the effect of tracking on the performance of the system a one-axis eastwest tracking flat plate photovoltaic is constructed Results for both the fixed flat plate and the one-axis tracking system were compared Output electrical current voltage and power of pumps motor were measured Pure water flow rate TDS and PH of produced water were measured for both systems Analysis of results show that a gain of 25 and 15 of electrical power and pure water flow respectively could be achieved using the eastwest one-axis tracking system compared with fixed flat plateForced vibration of Euler-Bernoulli beams by means of dynamic Green functionshttp://blogs.najah.edu/staff/haneen/article/Forced-vibration-of-EulerndashBernoulli-beams-by-means-of-dynamic-Green-functionsPublished ArticlesA method for determining the dynamic response of prismatic damped EulerBernoulli beams subjected to distributed and concentrated loads is presented The method yields exact solutions in closed form and may be used for single and multi-span beams single and multi-loaded beams and statically determinate and indeterminate beams Also Green functions for various beams with different homogenous and elastic boundary conditions are given In order to demonstrate the use of the Green functions method several examples are given Some of the obtained results are compared with those given in the referencesStochastic Vibration of a Laminated Composite Coated Beam Traversed by a Random Moving Loadhttp://blogs.najah.edu/staff/haneen/article/Stochastic-Vibration-of-a-Laminated-Composite-Coated-Beam-Traversed-by-a-Random-Moving-LoadPublished ArticlesStochastic Vibration of a Laminated Composite Coated Beam Traversed by a Random Moving Load H S Zibdeh and M Abu-Hilal 2003 Engineering Structures 25 397-404 doi:101016S0141-02960200181-5 Abstract: This paper deals with the random vibration of a simply-supported laminated composite coated beam traversed by a random moving load The moving load is assumed to move with accelerating decelerating and constant velocity types of motion Using basic analytical techniques this investigation aims at improving the random response of beams made from isotropic materials by using composite coats Closed form solutions for the variance of the response is obtained The results arrived at in this paper discuss the random vibration characteristics of the response of the aforementioned beam taking into account the speed effect lamina thickness and orientation of the coat effectsVibration of Beams with General Boundary Conditions due to a Moving Random Loadhttp://blogs.najah.edu/staff/haneen/article/Vibration-of-Beams-with-General-Boundary-Conditions-due-to-a-Moving-Random-LoadPublished ArticlesVibration of Beams with General Boundary Conditions due to a Moving Random Load M Abu-Hilal 2003 Archive of Applied Mechanics 72 637-650 Abstract: The transverse vibrations of elastic homogeneous isotropic beams with general boundary conditions due to a moving random force with constant mean value are analyzed The boundary conditions considered are pinned-pinned fixed-fixed pinned-fixed and fixed-free Based on Bernoulli beam theory the problem is described by means of partial differential equation Closed form solutions for the variance and the coefficient of variation of the beam deflection are obtained and compared for three types of the force motion: accelerated decelerated and uniform motion The effects of beam damping and the speed of the moving force on the dynamic response of beams are studied in detailMass and Stiffness Fixed Points of Vibrational Discrete Systemshttp://blogs.najah.edu/staff/haneen/article/Mass-and-Stiffness-Fixed-Points-of-Vibrational-Discrete-SystemsPublished ArticlesAbstract: The presence of fixed points in a frequency response of vibrating systems can complicate the vibration reduction if these points were not recognized In this paper the fixed points of vibrating discrete systems with n-degrees of freedom are investigated A procedure for determining the frequencies at which mass andor stiffness fixed points of discrete systems with n-degrees of freedom occur is presented A mass fixed point is an intersection of all amplitude curves which occurs in a frequency response of a vibrating system during a parametric variation of a mass At the frequency where this point occurs the vibration amplitudes remain constant regardless of the mass values A stiffness fixed point is defined as in a similar manner To verify the analysis performed all frequencies at which mass andor stiffness fixed points of a vibrating 3-mass system occur are determined analyticallyAnalysis of a Forced Strongly Non-Linear Two-Degree-of-Freedom System by Means of the Power-Series Methodhttp://blogs.najah.edu/staff/haneen/article/ANALYSIS-OF-A-FORCED-STRONGLY-NON-LINEAR-TWO-DEGREE-OF-FREEDOM-SYSTEM-BY-MEANS-OF-THE-POWER-SERIES-METHODPublished Articles Analysis of a Forced Strongly Non-linear Two-Degree-of-Freedom System by Means of The Power Series Method M I Qaisi and M Abu-Hilal 2001 Journal of Sound and Vibration 241 635-642 doi:101006jsvi20003312 Abstract: A power-series solution is presented for the periodic motion of an undamped strongly non-linear two-degree-of-freedom system excited by harmonic forces The analysis is facilitated by transforming the time variable into an harmonically oscillating time The frequency of the new time variable is determined by observing the equality between the rate of change of dynamical energy and the power delivered by the forces The results show good agreement with the modified Lindstedt-Poincare method and the incremental harmonic balance method Vibration of Beams with General Boundary Conditions Due to a Moving Harmonic Loadhttp://blogs.najah.edu/staff/haneen/article/VIBRATION-OF-BEAMS-WITH-GENERAL-BOUNDARY-CONDITIONS-DUE-TO-A-MOVING-HARMONIC-LOADPublished ArticlesVibrational behavior of elastic homogeneous isotropic beams with general boundary conditions due to a moving harmonic force is analyzed The analysis duly considers beams with four different boundary conditions; these include pinnedpinned fixedfixed pinnedfixed and fixedfree The response of beams are obtained in closed forms and compared for three types of the force motion: accelerated decelerated and uniform motion The effects of the moving speed and the frequency of the moving force on the dynamic behavior of beams are studied in detail Vibration Analysis of Beams with General Boundary Conditions Traversed by a Moving Forcehttp://blogs.najah.edu/staff/haneen/article/VIBRATION-ANALYSIS-OF-BEAMS-WITH-GENERAL-BOUNDARY-CONDITIONS-TRAVERSED-BY-A-MOVING-FORCEPublished Articles Vibration Analysis of Beams with General Boundary Conditions Traversed by a Moving Force M Abu-Hilal and H Zibdeh 2000 Journal of Sound and Vibration 229 377-388 Article No jsvi19992491 Abstract: This paper contributes to the basic fundamental problem of vibration of elastic homogeneous isotropic beam with general boundary conditions traversed by moving loads Closed-form solutions for the response of beams subjected to a single deterministic moving force are obtained The moving force is assumed to move with accelerating decelerating and constant velocity types of motion Results show in detail different cases of boundary conditions type of motion and damping Effects of variations of the corresponding parameters on the response of the beams are studied Results presented in this paper are readily applicable for further investigation in this field Comparison Between Simple Absorber and Absorber with 2 Degrees of Freedom to Reduce Vibrations of a 2 Degrees of Freedom System (in Arabic)http://blogs.najah.edu/staff/haneen/article/Comparison-Between-Simple-Absorber-and-Absorber-with-2-Degrees-of-Freedom-to-Reduce-Vibrations-of-a-2-Degrees-of-Freedom-System-in-ArabicPublished ArticlesIn this paper vibration absorbers with one and two degrees of freedom are applied to reduce the vibrations of a system with two degrees of freedom Several concepts are used The solution is done numerically The results are given in the form of frequency responses These results are discussed and compared with each other Recommendations to the design of vibration absorbers are given The vibrations of the studded system are reduced noticeably by using of absorbers Dependent on the selected damping value the obtained amplitudes at the working frequency vary between zero and 90 of the amplitude of the original system By using of two absorber in parallel the obtained amplitudes at the first natural frequency of the original system vary between 44 and 66 of the amplitudes of the original systemA Novel Design For Stone Hammering Machinehttp://blogs.najah.edu/staff/haneen/article/A-Novel-Design-For-Stone-Hammering-MachinePublished ArticlesA Novel Design For Stone Hammering Machine M Mohsen M Abu-Hilal M Abdeljawad and O Al-Jurf 1998 Proceeding of The Third Jordanian Mechanical Industrial Engineering Conference 819-830 Abstract: This paper presents an integrated framework for conceptual and analytical design of a stone hammering machine The process of hammering is investigated with the purpose of replicating what the stoneworker does mechanically The relation between impact momentum and indentation diameter is established for a certain type of limestone hammered by an indentor of a certain tip diameter A simple experiment is setup it is shown how the results dictate a certain type of design for a machine that hammers limestone into the common patterns that are used in Jordan The complete design of the device is presented including an explanation of the necessity for a constant velocity reciprocating mechanism CVRMFixed points of two-degree of freedom systemshttp://blogs.najah.edu/staff/haneen/article/Fixed-points-of-two-degree-of-freedom-systemsPublished Articles Fixed points of two-degree of freedom Systems M Abu-Hilal 1998 Journal of Shock and Vibration 5 199-205 ISSN 1070-9622 Abstract: The presence of fixed points in a frequency response of vibrating systems can greatly complicate the vibration reduction if these points are not recognized In this paper the fixed points of two-degree-of-freedom systems are studied The frequencies at which fixed points occur and their amplitudes are determined analytically