In this work, a vertical pulsating heat pipe heat exchanger (PHPHE) was designed for waste heat recovery, exchanging thermal energy between two air streams in a counterflow configuration. The heat exchanger consists of six rows, each row consists of one pulsating heat pipe (PHP), and each PHP has six turns. The working fluid used in the heat pipe was acetone with fill ratios of 50%, 60%, and 70%. The effect of evaporator inlet temperature at 40, 45, and 50°C and air velocity at 0.5, 0.7, and 0.9 m/s on the pulsating heat pipes consisting of three sections- evaporator, condenser, and adiabatic, whose dimensions were 25 x 25 x 10 cm, was studied. At the same time, the condenser temperature was maintained at 26°C. The system’s thermal resistance, effectiveness, and heat transfer were calculated using Engineering Equation Solver (EES) software. Results showed that the device's efficiency ranged from approximately 15% to 32%. The device performed better at a 50% fill ratio compared to other ratios, achieving high efficiency at low speeds.
In engineering, the ground in seismically active places may be subjected to static and seismic stresses. To avoid bearing capacity collapse, increasing the system's dynamic rigidity, and/or reducing dynamic fluctuations, it may be required to employ deep foundations instead of shallow ones. The axial aptitude and pipe pile distribution of load under static conditions have been well reported, but more study is needed to understand the dynamic axial response. Therefore, this research discusses the outputs of the 3D finite element models on the soil-pile behavior under different acceleration intensities and soil states by using MIDAS GTS NX. The pipe pile was represented as a simple elastic, and a modified Mohr-Coulomb mode
... Show MoreA numerical method is developed to obtain two-dimensional velocity and pressure distribution through a cylindrical pipe with cross jet flows. The method is based on solving partial differential equations for the conservation of mass and momentum by finite difference method to convert them into algebraic equations. This well-known problem is used to introduce the basic concepts of CFD including: the finite- difference mesh, the discrete nature of the numerical solution, and the dependence of the result on the mesh refinement. Staggered grid implementation of the numerical model is used. The set of algebraic equations is solved simultaneously by “SIMPLE” algorithm to obtain velocity and pressure distribution within a pipe. In order to
... Show MoreBackground: The study was designed to evaluate the effect of local application of exogenous VEGF/collagen I separately and as a combination in socket healing. Sixty male Albino Wistar rats were subjected for a surgical tooth extraction of upper 1st molar of both sides (right side was considered as experimental site, while left be the control one, treated with 1µL of normal saline). The rats were scarified at 3, 7, 14, 28 days post extraction. Socket healing was histologically examined with immunohistochemistochemical localization of ALP&FGF2. Materials and Method: Sixty male Albino Wistar rats were subjected for a surgical tooth extraction of upper 1stmolar of both sides (right side was considered as experimental site, while left be the
... Show MoreIn the recent decade, injection of nanoparticles (NPs) into underground formation as liquid nanodispersions has been suggested as a smart alternative for conventional methods in tertiary oil recovery projects from mature oil reservoirs. Such reservoirs, however, are strong candidates for carbon geo-sequestration (CGS) projects, and the presence of nanoparticles (NPs) after nanofluid-flooding can add more complexity to carbon geo-storage projects. Despite studies investigating CO2 injection and nanofluid-flooding for EOR projects, no information was reported about the potential synergistic effects of CO2 and NPs on enhanced oil recovery (EOR) and CGS concerning the interfacial tension (γ) of CO2-oil system. This study thus extensively inves
... Show MoreThe steady state performance of the counter rotating floating ring Journal bearing is analyzed with isothermal finite bearing theory. The effect of different parameters affecting the performance of the bearing (namely speed ratio, clearance ratio and radii ratio), have been investigated. The load carrying capacity of the bearing increasing with decreasing the radii ratio (R2/R1) of the ring and clearance ratio (c1/c2), in the other hand, the coefficient of friction increases with increasing the clearance and radii ratios, while decreases with incre4asing the bearing to journal speed ratio (γ). It is shown during this work that different operating conditions are greatly enhanced the performance
... Show MoreLaser assisted skin wound closure offers many distinct advantages over conventional closure
techniques. The objective of this in vitro experimental study, carried out at the Institute of Laser for
Postgraduate Studies/Baghdad University, was to determine the effectiveness of 980 nm diode laser in
welding of human skin wounds. Multiple 3-4 cm long full thickness incisions in a specimen of human
skin obtained from the discarded panniculus of an Abdominoplasty operation were tried to be laser
welded using a 4 mm spot diameter laser beam from a 980 nm diode laser at different laser parameters
and modes of action. The tensile strength at the weld site was analyzed experimentally. Although laser
assisted wound welding did
The concrete need curing for cement hydration that is a chemical reaction in each step require water supply throughout the time period. The traditional concrete cured by external method that prevents the concrete surface dry so that keeping the concrete mixture wet and warm. The internal curing was adopted in normal and high strength concrete such as reactive powder concrete. In present paper, experimental approach is to study the mechanical properties of reactive powder concrete cured internally with thermostone material. The materials that adopted to evaluate and find out the influences of the internal curing on the mechanical properties of reactive powder concrete is focused with d
Internal conversion coefficients (ICC) and electron–positron pair conversion coefficients (PCC) for multipole transition of the core nucleus 88Sr have been calculated theoretically. The calculation is based on the relativistic Dirac–Fock (DF) solutions using the so called ‘‘Frozen Orbital’’ approximation, takes into account the effect of atomic vacancies created in the conversion process, covering a transition energies of 1–5000 keV. A large number of points were used to minimize any errors due to mesh-size effects. The internal conversion coefficients display a smooth monotonic dependence on transition energy, multipolarity and atomic shell. Comparing the values of PCC to ICC, it is interesting to note, that the energy dep
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