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Nidal H. Abu-Hamdeh

Bio: Nidal H. Abu-Hamdeh is an academic researcher from King Abdulaziz University. The author has contributed to research in topics: Nanofluid & Heat transfer. The author has an hindex of 37, co-authored 229 publications receiving 4401 citations. Previous affiliations of Nidal H. Abu-Hamdeh include Jordan University of Science and Technology & Ohio State University.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the effect of bulk density, moisture content, salt concentration, and organic matter on the thermal conductivity of some sieved and repacked Jordanian soils was investigated through laboratory studies.
Abstract: The thermal conductivity of soil under a given set of conditions is most important as it relates to a soil's microclimate. The early growth and development of a crop may be determined to a large extent by microclimate. The effect of bulk density, moisture content, salt concentration, and organic matter on the thermal conductivity of some sieved and repacked Jordanian soils was investigated through laboratory studies. These laboratory experiments used the single probe method to determine thermal conductivity. The soils used were classified as sand, sandy loam, loam, and clay loam. The two salts used were NaCl and CaCl 2 , while addition of peat moss was used to increase the organic matter content, For the soils studied, thermal conductivity increased with increasing soil density and moisture content. Thermal conductivity ranged from 0.58 to 1.94 for sand, from 0.19 to 1.12 for sandy loam, from 0.29 to 0.76 for loam, and from 0.36 to 0.69 W/m K for clay loam at densities from 1.23 to 1.59 g cm 3 and water contents from 1.4 to 21.2%, The results also show that an increase in the amount of added salts at given moisture content (volumetric solution contents θ ranged from 0.03-0.12 m 3 m -3 for the sand and from 0.09-0.30 m 3 m 3 for the clay loam) decreased thermal conductivity. Increasing the percentage of soil organic matter decreased thermal conductivity, Finally, il was found that the sand had higher values of thermal conductivity than the clay loam for the same salt type and concentrations.

531 citations

Journal ArticleDOI
TL;DR: In this article, the effect of water content and bulk density on the specific heat, volumetric heat capacity, and thermal diffusivity of some sieved and repacked soils was investigated through laboratory studies.
Abstract: Thermal properties dictate the storage and movement of heat in soils and as such influence the temperature and heat flux in soils as a function of time and depth. The ability to monitor soil heat capacity is an important tool in managing the soil temperature regime to affect seed germination and crop growth. The effect of water content and bulk density on the specific heat, volumetric heat capacity, and thermal diffusivity of some sieved and repacked soils was investigated through laboratory studies. These laboratory experiments used the calorimetric method to determine specific heat of soils. The soils used were classified as sand and clay. For the type of soils studied, specific heat increased with increased moisture content. Also, volumetric heat capacity increased with increased moisture content and soil density. Volumetric heat capacity ranged from 1·48 to 3·54 MJ m−3 °C−1 for clay and from 1·09 to 3·04 MJ m−3 °C−1 for sand at moisture contents from 0 to 0·25 (kg kg−1) and densities from 1200 to 1400 kg m−3. Specific heat ranged from 1·17 to 2·25 kJ kg−1 °C−1 for clay and from 0·83 to 1·67 kJ kg−1 °C−1 for sand at moisture contents from 0·02 to 0·25 (kg kg−1) and soil density of 1300 kg m−3. The volumetric heat capacity and specific heat of soils observed in this study under varying moisture content and soil density were compared with independent estimates made using derived theoretical relations. The differences between the observed and predicted results were very small. Clay soil generally had higher specific heat and volumetric heat capacity than sandy soil for the same moisture content and soil density. The results also show that thermal diffusivity vary with moisture content and soil texture. Sandy soil exhibited a thermal diffusivity peak at a definite moisture content range. Clay soil, however, did not exhibit a sharp thermal diffusivity peak.

334 citations

Journal ArticleDOI
TL;DR: In this article, the effect of uniform inclined magnetic field is numerically analyzed in an open trapezoidal cavity filled with a porous layer and a ferrofluid layer under the effects of natural convection combined with entropy generation.
Abstract: In this study, natural convection combined with entropy generation of Fe3O4–water nanofluid within an open trapezoidal cavity filled with a porous layer and a ferrofluid layer under the effect of uniform inclined magnetic field is numerically analyzed. Porous layer is located on the bottom wall and heated from the left inclined wall. Bottom wall, right and left tilted walls of the cavity are adiabatic except for the active part along the left inclined wall where hot temperature Th is constant, upper open boundary is kept at constant cold temperature Tc. Governing equations with corresponding boundary conditions formulated in dimensionless stream function and vorticity using Brinkman-extended Darcy model for porous layer have been solved numerically using finite difference method. Numerical analysis has been carried out for a wide range of Hartmann number, magnetic field inclination angle, height of the porous layer and nanoparticles volume fraction. It has been found that an increase in Hartmann number leads to a growth of oscillations amplitude for average Nusselt number and average entropy generation. At the same time inclination angle α = π/2 illustrates unstable behavior of heat and fluid flow.

145 citations

Journal ArticleDOI
TL;DR: In this article, Nanomaterial as an additive dispersed in to paraffin to improve the melting process was used to obtain faster melting in a tank with various configurations of metallic fins with Y shape.
Abstract: Melting phenomena within a tank with various configurations of metallic fins with Y shape was performed by means of FVM. Fins are connected to hot surfaces. Nanomaterial as an additive dispersed in to paraffin to improve the melting process. Quicker melting can be obtained with use of NEPCM. Also, exergy loss was reported for various cases. Case 1 has lowest performance in view of liquid fraction (LF) and in comparison to 5th case, it has 15.8% lower performance. The best case in view of exergy loss is 4th case and Xd reduces about 73.7% with time augmentation. Reducing tendency of exergy drop is related to higher temperature of PCM with enhance of melt fraction. As expected, as LF augments, velocity of PCM enhances which provides greater Sgen,f. Regarding outcomes, the third case has greatest Sgen,f while the 4th case has minimum value of Sgen,f. Only the 3rd case has augmenting behavior with rise of time and other case has optimum point at t = 150 s. Sgen,th is reducing function of liquid fraction because converting solid to liquid provide greater temperature of PCM. The minimum of Sgen,th obtains for 4th case which is 1.59 time lower than 3rd case.

145 citations

Journal ArticleDOI
TL;DR: In this paper, a sinusoidal tank including inner circular cylinder was considered and to expedite the solidification, radial fins were installed over the inner cold cylinder to improve the conduction, CuO nano sized material was added and effects of size of particles were involved.
Abstract: In this research, sinusoidal tank including inner circular cylinder was considered and to expedite the solidification, radial fins were installed over the inner cold cylinder. To improve the conduction, CuO nano sized material was added and effects of size of particles were involved. The governing equations consist of energy equation with one source term of solid fraction and equation for distribution of ice fraction. To fins the solution, Galerkin approach was applied and different mesh configuration in various time step helps to capture the phenomena more accurate. Validation with experimental data shows the nice accommodation. So, influence of fins length and diameter of particles were imposed. As longer fins were employed, the solidification time reduces about 3.74% when dp = 40. As dp rises from 40 to 50, temperature augments and greater energy has been achieved because of augmentation of needed time from 175.44 to 264.05 s. Impact of dp on isotherms is more significant than fins length.

141 citations


Cited by
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01 May 1993
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

29,323 citations

Journal ArticleDOI
TL;DR: Energy foundations and other thermo-active ground structures, such as energy wells, pavement heating, and pavement heating represent an innovative technology that contributes to environmental protection and provides substan... as discussed by the authors.
Abstract: Energy foundations and other thermo-active ground structures, energy wells, and pavement heating represent an innovative technology that contributes to environmental protection and provides substan...

966 citations

Book ChapterDOI
28 Jan 2005
TL;DR: The Q12-40 density: ρ ((kg/m) specific heat: Cp (J/kg ·K) dynamic viscosity: ν ≡ μ/ρ (m/s) thermal conductivity: k, (W/m ·K), thermal diffusivity: α, ≡ k/(ρ · Cp) (m /s) Prandtl number: Pr, ≡ ν/α (−−) volumetric compressibility: β, (1/K).
Abstract: Geometry: shape, size, aspect ratio and orientation Flow Type: forced, natural, laminar, turbulent, internal, external Boundary: isothermal (Tw = constant) or isoflux (q̇w = constant) Fluid Type: viscous oil, water, gases or liquid metals Properties: all properties determined at film temperature Tf = (Tw + T∞)/2 Note: ρ and ν ∝ 1/Patm ⇒ see Q12-40 density: ρ ((kg/m) specific heat: Cp (J/kg ·K) dynamic viscosity: μ, (N · s/m) kinematic viscosity: ν ≡ μ/ρ (m/s) thermal conductivity: k, (W/m ·K) thermal diffusivity: α, ≡ k/(ρ · Cp) (m/s) Prandtl number: Pr, ≡ ν/α (−−) volumetric compressibility: β, (1/K)

636 citations

Journal ArticleDOI
TL;DR: In this paper, the suitability of different densification systems for biomass feedstocks and the impact these systems have on specific energy consumption and end-product quality are discussed, and the quality of the densified biomass for both domestic and international markets is evaluated using PFI (United States standard) or CEN (European standard).
Abstract: Developing uniformly formatted, densified feedstock from lignocellulosic biomass is of interest to achieve consistent physical properties such as size and shape, bulk and unit density, and durability, which significantly influence storage, transportation and handling characteristics, and, by extension, feedstock cost and quality. A variety of densification systems are considered for producing a uniform format feedstock commodity for bioenergy applications, including (i) pellet mill, (ii) cuber, (iii) screw extruder, (iv) briquette press, (v) roller press, (vi) tablet press, and (vii) agglomerator. Each of these systems has varying impacts on feedstock chemical and physical properties, and energy consumption. This review discusses the suitability of these densification systems for biomass feedstocks and the impact these systems have on specific energy consumption and end-product quality. For example, a briquette press is more flexible in terms of feedstock variables where higher moisture content and larger particles are acceptable for making good quality briquettes; or among different densification systems, a screw press consumes the most energy because it not only compresses but also shears and mixes the material. Pre-treatment options like pre-heating, grinding, steam explosion, torrefaction, and ammonia fiber explosion (AFEX) can also help to reduce specific energy consumption during densification and improve binding characteristics. Binding behavior can also be improved by adding natural binders, such as proteins, or commercial binders, such as lignosulfonates. The quality of the densified biomass for both domestic and international markets is evaluated using PFI (United States standard) or CEN (European standard). Published in 2011 by John Wiley & Sons, Ltd Re-use of this article is permitted in accordance with the Terms and Conditions set out at http://wileyonlinelibrary.com/onlineopen#OnlineOpen_Terms

549 citations