bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of diffusion bonded flat plate closed loop pulsating heat pipes with alternating porous media
Authors: Betancur Luis , Facin Arthur , Gonçalves Priscila , Paiva Kleber , Mantelli Marcia , Nuernberg Gustavo 
Published: May 2021

Abstract
This work aims to discuss the application of diffusion bonding process in the fabrication of flat plate pulsating heat pipes and to analyze the thermal performance effect of porous media structures applied to alternating channels in the evaporator section and compare it with a smooth conventional flat plate pulsating heat pipe. For that, two different copper flat plate pulsating heat pipes with five turns and 1.5 mm of inner diameter channels were fabricated, using diffusion bonding. Samples were made with two different diffusion process to evaluate the ability of the resulting device to keep the vacuum, avoiding the use of filler material during the welding process, which could result in contamination and, therefore, undesirable corrosion on both internal and external heat pipe surfaces. The results allowed to assess the quality of the bonded interface of two different configurations of the diffusion process. Microscopic results obtained on controllable pressure furnace and non-pressure control were analyzed, where the diffusion process with controlled pressure presented best results of continuity, alignment, and tightness. A comparison of the heat transfer characteristics between the two devices was performed under the same experimental conditions; for both devices, the thermal resistance in horizontal position showed to be like heat transfer of pure conductive copper plate. However, pulsating heat pipe containing smooth channels showed the lower thermal resistance in vertical position and filling ratio of 50%.
Water-filled heat pipes for CubeSat thermal control
Authors: van Gerner H J , Brouwer H , de Groot Z , Guo J 
Published: May 2021

Abstract
Currently, the amount of electrical power that is available for CubeSat’s is very small and for this reason, simple thermal conductance through the frame of the CubeSat is sufficient for most CubeSat missions. However, deployable solar panels have been developed recently and peak powers up to 40W can now be generated. This higher generated electrical power results in more waste heat and potentially too high temperatures inside the CubeSat. For this reason, the use of water-filled heat pipes is studied, since these are cheap, widely commercially available, and can be bent in the desired shape. Both the condenser and evaporator thermal resistance and the total heat transfer capacity of these heat pipes have been measured for a wide range of temperatures with a unique automated setup that uses Peltier elements to control the temperature. Furthermore, the heat pipes have been subjected to multiple freeze/thaw cycles and start-ups from a frozen state. After these successful tests, a heat pipe was integrated in a CubeSat and tests were carried out in several orientations. The tests show that commercially available water-filled heat pipes are suitable for CubeSat thermal control.
A method of fast quality control inspection of loop heat pipe
Authors: Huang Bin-Juine , Huang H H , Liang T L , Yang P E , Hu S S 
Published: May 2021

Abstract
The dynamic behaviour of loop heat pipe (LHP) changes with heat load and physical properties of LHP such as fluid charging, wick material, and tolerance in manufacture. The start-up phenomena of a LHP can be classified into four modes, according to the heat load Qin
: failure mode, oscillating mode, overshoot mode, and normal mode. It is found that the operation mode is related to the rate of temperature rise in evaporator during initial transient performance using a step heating load. The abnormal high rate of temperature rise can be observed for LHP with failure, oscillating or overshoot mode performance. Based on this phenomenon, the normal-mode performance of LHP can be assured from a short transient test in about 80s using a step heat load, instead of using steady-state test (taking 1,800s). This transient test method has been applied in the quality inspection of commercial loop heat pipe in mass production. No LHP failure was found for more than 10 years for about 30,000 sets of street LED luminaires designed with LHP.
Black box modelling of a latent heat thermal energy storage system coupled with heat pipes
Authors: Arteconi A , Ferracuti F , Tascioni R , Mahkamov K , Kenisarin M , Costa C , Cabeza L F , de Gracia A , Halimic E , Mullen D , Lynn K , Cioccolanti L 
Published: May 2021

Abstract
This paper presents black box models to represent a LHTESS (Latent Heat Thermal Energy Storage System) coupled with heat pipes, aimed at increasing the storage performance and at decreasing the time of charging/discharging. The presented storage system is part of a micro solar CHP plant and the developed model is intended to be used in the simulation tool of the overall system, thus it has to be accurate but also fast computing. Black box data driven models are considered, trained by means of numerical data obtained from a white box detailed model of the LHTESS and heat pipes system. A year round simulation of the system during its normal operation within the micro solar CHP plant is used as dataset. Then the black box models are trained and finally validated on these data. Results show the need for a black box model that can take into account the different seasonal performance of the LHTESS. In this analysis the best fit was achieved by means of Random Forest models with an accuracy higher than 90%.
Thin film evaporation model for two-phase capillary heat transfer devices: examination of boundary conditions and vapour pressure gradient
Authors: Ahmed S , Pandey M 
Published: May 2021

Abstract
Thin film evaporation model has been used by several researchers to study the transport phenomena of two-phase capillary devices, such as heat pipes and capillary pumped loops. The present work is focused on mathematical modeling of the evaporation phenomena in such devices. Liquid-vapour interface in the evaporator is modelled using a thin film model and the lubrication approximation, along with a slip boundary condition at the wall and a shear boundary condition at the interface. Different models are used for the evaporating mass flux and the vapour pressure gradient at the liquid-vapour interface is considered. An attempt is also made to determine the non-evaporating film thickness that satisfies the underlying physics. The film thickness profile and the pressure components are obtained by numerical simulations. It is found that the choice of the evaporating mass flux model has a significant effect on the results, and is very important for heat transfer characterization.
Beam Tracking Using Least Mean Squares Algorithm for single-cell Massive MIMO Communication System
Authors: Asi Ban A. , Mohmood Farhad E. , AL-Ibadi Mohanad A. 
Published: May 2021

Abstract
Millimetres wave (mm-wave) is an attractive option for high data rate applications in the 5G wireless communication systems that require proper beamforming and channel tracking. In this paper, we study, analyse and compare the performance of two closely related stochastic gradient descent-based approaches, namely the least mean square (LMS) algorithm, and the normalized least mean square (NLMS) algorithm, for tracking the transmit array beam in addition to the channel status. These adaptive filters usually result in a trade-off between convergence and accuracy. We found that the quality of the tracking results, measured in mean squared error (MSE) sense, are heavily dependent on the present step-the size of the gradient descent.
On the Performance of Cooperative Relaying with Maximum-Ratio Combination (MRC) for mmWave Systems
Authors: Ali Reyam H. , Mahmood Mahmood A. , Ahmed Mohamad A. 
Published: May 2021

Abstract
In this paper, cooperative communication using a two-way relaying network (TWRN) is considered for millimeter-wave (mmWave) communications. Two schemes of TWRN are employed for cooperation and performance evaluation, which are amplify-and-forward (AF) and decode-and-forward (DF) relays. Furthermore, maximum-ratio combination (MRC) is utilized in each node in the proposed systems. It is noteworthy that MRC is exploited in this paper as a channel equalization and also to maximize the strength of the received signals at each node. The performance is evaluated for the proposed systems over 28 and 73 GHz using one and two parallel AF and DF relays in the presence of the direct path. Moreover, compassion between the two frequencies is achieved, via obtaining the bit-error-rate (BER) against different values of signal-to-noise ratios (SNR)’s, by assuming the same distances between the source, relay/relays, and the destination. The results show the outperforming of 28 GHz in this performance metric, i.e. BER-SNR, by using AF relaying, due to the amplification factor added to the signal to compensate for the inherent attenuation in this frequency band. Moreover, the proposed DF relay schemes have limited compensation to the attenuated signals comparing to the AF relay.
A Rectangular Monopole Filtenna with U-shaped Slot for 5G Applications
Authors: Al-Arajee T H , Sayidmarie K H 
Published: May 2021

Abstract
A filtering antenna for 5G applications is proposed in this study, where the resonant element has a U-shaped slot embedded into the microstrip feed line so that no extra size is required. The proposedfiltenna has a very compact size of only 35 * 47 mm 2. Using CST Microwave Studio Suite, a comprehensive parametric analysis was done to evaluate and optimize the characteristics of the proposed filtenna. The filtenna is aimed for the 5G 3.4-3.8 GHz, as it covers a bandwidth of 412MHz (3.395-3.807GHz) witha good reflection coefficient of -22.96dBat the center frequency. The U-shaped slot enhances the lower shoulder of the antenna frequency response and has no effect on the radiation at the desired band.
Obtaining Performance Similar to Rectangular Planar Antenna Using Crossed Arrays with Smaller Number of Elements
Authors: Khmees Abdulrazaq Abdulhaq , Mohammed Jafar Ramadhan 
Published: May 2021

Abstract
Conventional rectangular planar arrays with fully filled elements are practically very complicated especially for large arrays. They usually occupy a large space. Thus, any reduction in the space and the number of the array elements is highly desirable in many applications. In this paper, the authors present a novel technique for obtaining a performance similar to that of the conventional rectangular planar antenna using two orthogonal crossed arrays with a smaller number of elements. The proposed technique consists of redesigning the amplitude element excitations of only two crossed arrays using either deterministic or optimization algorithms. Simulation results are shown to prove the proposed idea.
Comparative Study the Effect of Antenna Selection on Capacity and Energy Efficiency of 5G Systems
Authors: Abdullah Sawsan N. , Mahmood Farhad E. , Mohammed Ali Y.E. 
Published: May 2021

Abstract
As a result of the rapid growth in wireless communications and the increase in the number of users of cellular phones around the world, massive multi-output, and multi-input (massive MIMO) systems have been used. The main drawback of such a system is the increase in the number of antennas and the amount of energy consumed. To mitigate that the number of active antennas can be reduced to save some energy. In this paper, we will study different algorithms for choosing the suitable antennas in MIMO systems, subject to keeping an acceptable level of bit rate and energy efficiency in the system. The study will also consider the amount of complexity for each algorithm based on the consumed time to perform each algorithm in MATLAB.
Performance Optimization on GPGPU & Multicore CPU Using Roofline Model
Authors: Allayla Noor M. , Dawwd Shefa A. 
Published: May 2021

Abstract
The roofline model introduced in this paper to evaluate the best optimized platform for training the neural network that used to recognize handwritten digits under multicore CPU and general-purpose GPU (GPGPU) as hardware environment. The pattern parallel training technique for MNIST dataset is applied. The parallel network training of MNIST using different data layout of multicore CPU and GPGPU is presented. Different bottlenecks have been explained by applying the roofline model. The most suitable platform is selected according to layouts and constrains either for memory or computation bounds. The computational intensity of all rooflines is moved toward right, then the performance is increased. As a result of optimization, and with the diversity of the available data size, core number, operational strength, the most suitable hardware platform is selected.
Model of Integrated of Car Brake-Active Suspension of Quarter Car Model By Using LQR Control Under Periodic Road Excitation
Authors: Harly Muchammad , Marji  , Yoto  , Paryono  
Published: May 2021

Abstract
The most important technology in a vehicle is the stability of the direction of the vehicle and the comfort of the passengers. For stability, direct yaw control is used via ABS / TCS / DSC, while for convenience, use the active suspension. These two solutions also contribute to one another. In this research paper is produced and explained about the use of LQR control to control the response of the sprung mass to achieve high damping ratios in isolating the excitation force from nonlinear road surfaces. The simulation results prove that the damping ratio controlled by LQR was better than compared by using PID.
Analysis and Simulation of a Single Phase Nine Level Inverter with Reduction in Power Switching Devices
Authors: Mahmood Saif S. , Younus Shawkat M. 
Published: May 2021

Abstract
This paper present analysis and modelling of single phase nine level inverter, a Wide range of Modulation index (M) varied between 0.05-1.05 is achieved by two switching strategies (Optimized harmonic stepped waveform (OHSW), (Optimal minimization of total harmonic distortion (OTHD)) the first strategy focusses on harmonic elimination and the other on reducing output voltage total harmonic distortion (THD). Calculation of switching angles for both equal and unequal dc sources is done by Genetic Algorithm (GA). simulation in Matlab, PSpice and PSIM is presented in this work.
The influence of the interface layer between the electron transport layer and absorber on the performance of perovskite solar cells
Authors: Qasim Agha Dena N , Algwari Qais Th 
Published: May 2021

Abstract
High efficiency, lightweight, and cost-effectiveness put the perovskite solar cells to the top of the focus researches of solar cells. The architecture of the cell especially the energy band alignment at the interface is a critical issue in the cell performance. In the current paper, the solar cell structure under investigation consists of TiO2, CH3NH3PbI3, and Spiro OMe TAD as electron transport layer, absorber and hole transport layer respectively. A 3C-SiC material with energy gap of 2.420 eV was used as interface layer. The role of the interface layer between the perovskite and electron transport layer was considered. Before inserting the interface layer, a parametric study including the thickness and doping of each layer, was achieved. The results showed that the best performance of the cell at a thickness of 400 nm, 300 nm, 200 nm for absorber layer, ETL, and HTL respectively, with a doping concentration of 1014 cm-3, 1019 cm-3, 1019 cm-3 for the same layers. These parameters give a Voc, Jsc, FF, and PCE of 1.11 V, 28.9 mA·cm-2, 83.19%, and 26.88% respectively. Inserting an interface layer improved the performance of the cell where the PCE increased over 29% at a thickness of 90 nm. The results showed that the parameters of the interface layer play a significant role in cell performance.
Design and simulation of cascaded H-bridge 5-level inverter for grid connection system based on multi-carrier PWM technique
Authors: Maaroof Hadeel S , Al-Badrani Harith , Younis Ahmad T 
Published: May 2021

Abstract
Cascaded H-Bridge (CHB) multi-level inverter has become attractive in medium voltage and grid connection to improve power quality with high efficiency, and low switching losses. Voltage Oriented Control (VOC) regulates the injected power and the connection between the cascaded H-bridge inverter and the utility grid. In the modulation stage for the VOC, there are several techniques such as Space Vector Pulse Width Modulation (SVPWM), Multi-Carrier Pulse Width Modulation (MCPWM), Selective Harmonic Elimination (SHE) used to obtain gating pulses for the IGBTs switches. In this paper, a three-phase 5-level CHB inverter with a grid connection system is present and the technique of MCPWM is used. A comparative study between each method of (MCPWM) using MATLAB/Simulink environment has been done on the Total Harmonic Distortion (THD) for inverter phase voltage and current with different injected reference current values. It is found that phase current THD is less with the Phase Shift PWM (PS-PWM) technique.
Evaluation of Ground Motion Definition on the Seismic Analysis of Reinforced Concrete Moment Frame Structure
Authors: Ornthammarath T , Myint K M 
Published: May 2021

Abstract
The primary objective of the study is to analyze the effect of the horizontal definition in the ground motion selection, in which, how the target spectra of DBE and MCE resulted from the geometric mean method and NGA West-2 Sa RotD100, the maximum direction method is different from each other. The analysis of the seismic performance of the building is the secondary aim of the research. The linear design methods of equivalent lateral force analysis, response spectrum and seismic response history analysis are performed based on the Myanmar seismic design code to figure out and compare the building responses such as story displacement, story drift, story base shear, and story overturning moment. In this study, the irregular shaped RC building structural responses are also explored with equivalent lateral force analysis (EQLF), response spectrum analysis (RSA) and linear response history analysis (LRHA). The recent ground motion definition response shows great potential in improving the performance-based design of considered structures.
Reliability-based prediction of landslide using efficient Monte Carlo Simulation
Authors: Joe E J , Ali N , Jusoh S N 
Published: May 2021

Abstract
Several studies have attempted to develop thresholds for prediction of landslide initiation due to antecedent rainfall by using the physical-based approach. The approach offers a better understanding of the underlying process of the landslide mechanism. In the previous studies, however, determinate values of hydro-mechanical soil parameters are commonly considered, neglecting the uncertainties of the variables. Thus, this study aims to propose a relatively computationally, inexpensive reliability approach to address the uncertainties of the multivariate. The application of the proposed model is demonstrated by taking a case study from Sabah, Malaysia. The Latin Hypercube Sampling was adopted for efficient sampling, while the dependencies of the multivariate were modelled using a higher-order copula. The infiltration process and slope stability were assessed based on a fully-coupled seepage-deformation and shear strength reduction technique, respectively in a finite element programme. The probabilities of failure for various antecedent rainfall condition were computed by using Monte Carlo Simulation. In order to reduce the computational cost of the simulation, the Multilayer Perceptron regressor was applied to form the non-linear surrogate model for an implicit limit state function.
Feasibility of low impact development measures to mitigate inundation in tidal – impacted urban area: A case in Ho Chi Minh City, Vietnam
Authors: Pham N , Cabaltica A , Pham H T 
Published: May 2021

Abstract
Recently, urban inundation is becoming more severe in Ho Chi Minh City. Many structural measures have been proposed, but low impact development (LID) measures have not been sufficiently considered. This study quantitatively investigated the possibility of LID measures in District 12, Ho Chi Minh City using modelling approach. Based on the collected secondary data on land use, sewer network, and terrain elevation, a semi-two-dimensional storm water management model (PCSWMM-2D) was constructed and calibrated against heavy rainfall and high tidal event on 26 September 2016. Errors between measured and simulated inundated depths at several positions was smaller than 5%; thus, the calibrated model was at reliable accuracy to predict design scenarios. Using 10-year return period scenarios of tidal levels at Sai Gon River and rainfall at Tan Son Hoa gauging station, the model was used to analyse several designed LID measures including green roof, pervious pavement, and storage or flood retention lake/pond. The simulated results indicated that if green roof and pervious pavement are separately applied, the average magnitude of inundation depth can be reduced by 11.4% and 14.0%, respectively. Meanwhile, when a well-designed storage system including a gated-flood retention lake in combination with suitable conduits and a pumping station is constructed, the flooding situation is completely controlled. In conclusion, it is suggested that to manage urban inundation in terms of sustainable development for Ho Chi Minh City, a well-designed storage system is needed prior to the urbanizing area. In addition, those LID measures should be widely applied as long-term strategy for flooding management in Ho Chi Minh City.
Stability of Railway Embankment in Saturated and Unsaturated Conditions
Authors: Roshan M J , Rashid A S A , Wahab N A , Hezmi M A , Jusoh S N , Azmi M 
Published: May 2021

AbstractSlope failure is a vital issue in civil engineering infrastructures. Besides, climate change implications made this problem more critical. Therefore, in this study, a railway embankment’s slope stability has been studied in saturated and unsaturated conditions. The soil sample was collected from Universiti Teknologi Malaysia, Johor Bahru. The necessary and required data obtained through lab experiments. The obtained data from lab experiments then used in Seep/W and Slope/W to model the railway embankment numerically. The results obtained from this study indicate that rainfall infiltration plays a vital role in the safety factor value. The obtained results also depicted that both rainfall intensity and duration play an important role in slope stability. The factor of safety showed a declining pattern with increasing rainfall and duration of rainfall. The safety factor decrement occurred since the matric suction was reduced (negative pore water pressure) by rainfall infiltration. Besides, the safety factor decrease was more acute when train load was applied in a rainy period. Thus, it is suggested that in a long period of rainy time, the railway authorities should stop the train operation, or the embankment stability should be increased using some stabilizations methods in the planning and designing stage.