bluuebunny/crossref_metadata_2025 huggingface dataset:
Experiments during AC current transition in ISTTOK and the hypothesis of ballistic runaway electrons
Authors: Malaquias A , Hole M , Henriques R B , Nedzelskiy I S , Plyusnin V V
Published: July 2022

The operation of the Instituto Superior Técnico Tokamak (ISTTOK) in the alternating current (AC) regime is characterized by the presence of a residual plasma density during the current transition, i.e. when the plasma current crosses the zero value. Contrary to what has been reported in other AC experiments, the pressure-like profiles obtained by the heavy ion beam diagnostic (the product of plasma density with a known function of plasma temperature) do not show evidence of the co-existence of two anti-parallel currents. This is also confirmed by the fact that in these experiments the plasma current and the V
loop both cross the zero value at the same instant. The Murakami–Hugill plots reveal that during the transition the plasma current decays faster than the Hugill limit and that the subsequent ramp-up phase is sustained by runaway electron (RE) currents. It is hypothesized that during plasma current decay a population of REs can enter the following semi-cycle of the discharge. A trajectory simulation model including the forces at play shows that the retardation effect of the friction and molecular forces can cause the dampening of REs (within 20 μs) with energy below 1 keV inside the chamber (without external vertical correction magnetic fields), thus ionizing the background gas. Faster REs (above 1 keV) can also contribute to the ionization of the background gas (e.g. within 50 μs for 3 keV energy electrons) but require a vertical magnetic field to balance the gradB and curvature drifts. This could explain why tuning the vertical field and dosing the background pressure to obtain successful AC discharges is usually challenging.
Analytic theory of ideal-MHD vertical displacements in tokamak plasmas
Authors: Yolbarsop A , Porcelli F , Liu Wandong , Fitzpatrick R
Published: July 2022

An analytic derivation of the relevant dispersion relation for vertical displacements in shaped tokamak plasmas is presented, valid for arbitrary values of the ellipticity parameter. The theory is developed within the framework of the reduced ideal-MHD model. A nearby, perfectly conducting wall can provide passive feedback stabilization of vertical displacements on the ideal-MHD timescale. The mechanism for passive stabilization relies on image currents induced on the metallic wall. However, if the plasma extends to the magnetic separatrix, where magnetic X-points are located, as in the case of a divertor tokamak configuration, perturbed axisymmetric currents carried by the plasma in the vicinity of the X-points are triggered. It is shown that these X-point currents can provide passive feedback stabilization, even in the absence of a nearby wall. X-point currents are excited due to the resonant nature of magnetic X-points with respect to toroidal axisymmetric perturbations. An intermediate case, where the plasma boundary is located just inside the magnetic separatrix, is also analyzed, providing additional insight into the stabilization mechanism.
Characterization of strongly coupled plasmas produced in argon supercritical fluids
Authors: Lee Seungtaek , Lee Juho , Yoon Young Dae , Kim Dong Eon , Yun Gunsu
Published: July 2022

Strongly coupled plasmas (SCPs) exist in various places throughout the Universe, examples of which are inertial confinement fusion experiments, Jovian planets’ cores, neutron stars, and white dwarf stars. In recent decades, theoretical and numerical studies have been pursued to characterize the equation of states and thermodynamic properties of SCPs, which are fundamentally different from those of weakly coupled plasmas. One of the essential research topics is energy transport by radiation or opacity. In particular, in a subcritical medium at a low temperature, condensation renders the medium inhomogeneous, which significantly affects the radiation transport or opacity. However, no study has been conducted for opacity in inhomogeneous supercritical fluids (SCFs). A recent study reveals that an inhomogeneous SCF with nanometer-sized clusters and micrometer-sized droplets can be prepared. Here, we experimentally demonstrate that the emission timescale of an SCP in an inhomogeneous SCF is extended by up to 50% compared to that in a homogeneous SCF. This implies that the inhomogeneity of the SCF significantly enhances the photon confinement. This result is expected to draw interest in the investigation of radiation transport or opacity in the inhomogeneous SCF. A better understanding will lead to a method for increasing the brightness and light emission time from a dense plasma.
Permittivity modulation in Si-based PIN diode by electron irradiation
Authors: Wang Yisong , Gong Min , Li Yun , Yang Zhimei , Rong Chenshuo , Huang Mingmin , Ma Yao , Li Jianghuan
Published: July 2022

In this paper, we investigate the influence of defects induced by different doses of electron irradiation on the real part of permittivity of Si-based PIN diodes with a deep-level transient spectrum test. For a more precise result, the relationship between the real part of the permittivity of the sample and the irradiation dose, temperature and annealing is studied. The results show that the real part of the permittivity changes significantly with the irradiation dose and temperature. The absolute value of the real part of the permittivity decreases with the decrease in temperature, and the changing trend decreases after annealing. The deep-level transient spectroscopy results illustrate that different states of defects caused by radiation and annealing have changed the free carrier mobility, free carrier density and charge balance in the material, which means they have a significant impact on the electrical characteristics of the samples. The I–V and C–V curves are obtained through experiments to extract the leakage current and carrier concentration. The I–V characteristic and the permittivity are subjected to temperature-variation analysis.
Flexible ultra-wideband cartoon-shaped antenna based on a composite with customizable dielectric properties
Authors: Deng Hao , Wei Yiqing , Jing Huihui , Zhang Rui , Chen Qinwen , Wang Jiayun , Qu Zeng , Duan Junping , Zhang Binzhen
Published: July 2022

This paper presents a flexible ultra-wideband (UWB) and deformation-insensitive antenna. The proposed antenna was based on a Mickey-shaped patch, a coplanar waveguide fed, and a flexible composite substrate, which was built by a polydimethylsiloxane (PDMS) matrix and short-diameter powders of polytetrafluoroethylene (PTFE), with customizable dielectric properties. Furthermore, PTFE, magnesium oxide, titanium oxide, and zirconia powders were used as four fillers with different weight ratios to modify and control the dielectric properties of the dielectric substrate (the relative permittivity: 2.75–3.07, the dielectric loss tangent: 0.02–0.05), and then we characterized PDMS-based composites through Young’s modulus, Raman spectra, and surface topography. Finally, we fabricated and measured the proposed antenna with the dimensions of 50 mm × 60 mm × 0.5 mm. The measured reflection coefficient curves showed an operating frequency band from 1.9 GHz to 43.5 GHz, and the measured fractional bandwidth reached 183.3%. It was proved that the antenna had stable performance when it was bent or stretched. Moreover, the antenna was simulated and measured in the proximity of the human body, which verified the antenna robustness and safety for use on a human. The proposed UWB and deformation-insensitive antenna is a promising candidate for wearable applications and wireless communication.
Effect of stretch limit change on hyperelastic dielectric actuation of styrene–ethylene/butylene–styrene (SEBS) copolymer organogels
Authors: Lau Gih-Keong , Ren Zhe-Xian , Chiang Kuan-Ting
Published: July 2022

Harder dielectric elastomers are structurally stronger than soft ones but hardly actuate under electrostatic pressure. It remains unclear which property limits harder dielectric elastomers from producing as large actuation as soft ones. This study shows that the change in stretch limit rather than modulus bounds the ultimate dielectric actuation. A larger ultimate stretch warrants a pre-stretched membrane to further thin down and expand biaxially relative to the pre-stretch state. Theory and experiments showed that pre-stretch alters the maximum stretchability and ultimate dielectric actuation. An optimal pre-stretch helps maximize the ultimate actuation close to

2

times radially so long as the corresponding total stretch did not exceed the elastomer’s fracture limit. Hence, a stretchy harder dielectric elastomer stands a chance of producing as large ultimate actuation as soft ones do. To validate the theory, we tested three commercial grades of styrene–ethylene/butylene–styrene copolymers (SEBS) organogels with different oil content and shore hardness. The tests showed that a 20 A-hardness organogel of low toughness actuated less ultimately, but a 10 A-hardness organogel of greater toughness actuated as much as an 8 A-hardness organogel does. This 10 A-hardness SEBS organogel showed an ultimate elongation of 1192%, and 3.1 times the shear modulus and seven times the tensile strength of 3 M VHB 4910. When being optimally pre-stretched for 3.5 times radially, it produced a substantial hyperelastic dielectric actuation up to 104% active areal strain at 277 MV m−1, comparable to the actuation generated by the over-stiffened VHB DEAs. Unlike VHB DEAs, these harder SEBS DEAs generated hyperelastic actuation free from severe viscoelastic drift. The high performance of SEBS organogels can potentially meet the need for forceful artificial muscles to drive bio-inspired robots.
Fractional order mathematical model of monkeypox transmission dynamics
Authors: Peter Olumuyiwa James , Oguntolu Festus Abiodun , Ojo Mayowa M , Olayinka Oyeniyi Abdulmumin , Jan Rashid , Khan Ilyas
Published: July 2022

In this paper, we present a deterministic mathematical model of monkeypox virus by using both classical and fractional-order differential equations. The model includes all of the possible interactions that contribute to disease spread in the population. We investigate the model's stability results in the disease-free case when R
0 < 1. When R
0 < 1, we show that the model is stable, otherwise it is unstable. To obtain the best fit that describes the dynamics of this disease in Nigeria, the model is fitted using the nonlinear least square method on cumulative reported cases of monkeypox virus from Nigeria between January to December 2019. Furthermore, adequate conditions for the existence and uniqueness of the solution of the model have been proved. We run numerous simulations of the proposed monkeypox model with varied input parameters to investigate the intricate dynamics of monkeypox infection under the effect of various system input parameters. We investigate the system's dynamical behavior to develop appropriate infection control policies. This allows the public to understand the significance of control parameters in the eradication of monkeypox in the population. Lowering the order of fractional derivatives has resulted in significant modifications. To the community's policymakers, we offered numerous parameters for the control of monkeypox.
Eco-friendly Green Synthesis of stable ZnO nanoparticles using citrus limon: X-Ray Diffraction Analysis and Optical Properties
Authors: Kem Anamika , Ansari Mohd Rehan , Prathap P , Jayasimhadri M , Peta Koteswara Rao
Published: July 2022

Eco-friendly stable ZnO nanoparticles (NPs) were synthesized by sol-gel method using citrus limon as a chelating agent. The structural analysis and optical properties of ZnO NPs annealed in air ambient at different temperatures ranging from 600 to 900 °C are reported. A detailed x-ray diffraction (XRD) analysis of ZnO NPs has been discussed. Morphological and optical properties of the NPs were investigated using Field Emission Scanning Electron Microscopy (FE-SEM), XRD, Diffuse Reflectance Spectroscopy (DRS), Photoluminescence (PL), Fourier Transform Infrared spectroscopy (FTIR) and Raman Spectroscopy techniques. The FE-SEM reveals that the average particle size of ZnO NPs increased from 62 to 77 nm due to agglomeration of particles or Ostwald ripening which usually happens at high temperature. Physical and microstructural properties such as crystallite size, strain, stress and dislocation density of ZnO NPs were obtained from XRD spectra studies and compared the estimated parameters by various models. It is observed that, the crystallite size increased after annealing and the strain present in NPs is due to defects. Kubelka-Munk function is used to obtain bandgap of NPs from DRS spectra. A slight decrease in the bandgap of ZnO NPs is due to the increase in particle size. PL spectra reveals that the emission around 402 nm near the UV region is attributed to the near band edge emission (NBE) and emission peaks in a visible region is due to the transition of electrons from traps in bandgap to the valence band.
Tuning of band gap by anion variation of Ga2TiX6 (X = Cl, Br, I) for solar cells and renewable energy
Authors: Al-Muhimeed Tahani I , Alzahrani Jameelah , Rouf Syed Awais , Al-Qaisi Samah , Anbarasan Radhakrishnan , Mahmood Q , Albalawi Hind , Alharthi Sarah , Amin Mohammed A , Somaily H H , Morsi Manal
Published: July 2022

Vacancy-ordered double perovskites have been studied vastly for energy applications for the last few decades. In this article, we have investigated the optical and thermoelectric characteristics of Ga2TiX6 (X = Cl, Br, I). The phonons dispersions, formation energy, and tolerance factors reveal dynamic and structural stabilities. The predicted band gaps turn out to be 2.74 eV, 2.0 eV, and 1.32 eV for Ga2TiCl6, Ga2TiBr6, and Ga2TiI6, respectively, corresponding to the absorption bands 275 nm to 413 nm, 365 nm to 539 nm, and 413 nm to 689 nm. Therefore, the absorption band in the entire visible region for Ga2TiI6 makes it an excellent material for solar cells. The optical characteristics are explained by dielectric constants (ε
1, ε
2), absorption coefficient, and dielectric constants. Thermoelectric efficiency is addressed by calculating the figure of merit to highlight the potential of the investigated materials for thermoelectric applications.
A possible subclassification of fast radio bursts
Authors: Guo Han-Yue , Wei Hao
Published: July 2022

Although fast radio bursts (FRBs) have been an active field in astronomy and cosmology, their origin is still unknown to date. One of the interesting topics is the classification of FRBs, which is closely related to the origin of FRBs. Different physical mechanisms are required by different classes of FRBs. In the literature, they usually could be classified into non-repeating and repeating FRBs. Well motivated by the observations, here we are interested in the possible subclassification of FRBs. By using the first CHIME/FRB catalog, we propose to subclassify non-repeating (type I) FRBs into type Ia and Ib FRBs. The distribution of type Ia FRBs is delayed with respect to the cosmic star formation history (SFH), and hence they are probably associated with old stellar populations, while the distribution of type Ib FRBs tracks SFH, and hence they are probably associated with young stellar populations. Accordingly, the physical criteria for this subclassification of type I FRBs have been clearly determined. We find that there are some tight empirical correlations for type Ia FRBs but not for type Ib FRBs, and vice versa. These make them different in physical properties. Similarly, we suggest that repeating (type II) FRBs could also be subclassified into type IIa and IIb FRBs. A universal subclassification scheme is given at the end. This subclassification of FRBs might help us to reveal quite different physical mechanisms behind them, and improve their applications in astronomy and cosmology.
Measuring CP violation in rare W decays at the LHC*
Authors: Lu Peng-Cheng , Si Zong-Guo , Wang Zhe , Yang Xing-Hua
Published: July 2022

Heavy Majorana neutrinos beyond the standard model can simultaneously explain the origin of tiny neutrino masses and matter-antimatter asymmetry in our Universe. The existence of heavy Majorana neutrinos will also lead to lepton number violation and confirm the possibility of rare lepton-number-violating W decays. With contributions from two different Majorana neutrinos, nonzero CP asymmetry may be generated from the rate difference between W decay and its CP-conjugate process. The aim of this study is to investigate the prospects of measuring CP violation in rare W decays via Majorana neutrinos at the LHC. Our calculations show that the induced CP asymmetry is independent of the Majorana neutrino mass for

. Such a CP asymmetry, if observed, would in turn provide unambiguous evidence of new physics beyond the standard model.
A New Post-hoc Flat Field Measurement Method for the Solar X-Ray and Extreme Ultraviolet Imager Onboard the FengYun-3E Satellite
Authors: Song Qiao , Bai Xianyong , Chen Bo , Hu Xiuqing , Chen Yajie , Hou Zhenyong , Zhang Xiaofan , He Lingping , Song Kefei , Zhang Peng , Wang Jing-Song , Zhang Xiaoxin , Zong Weiguo , Dun Jinping , Tian Hui , Deng Yuanyong
Published: July 2022

Extreme ultraviolet (EUV) observations are widely used in solar activity research and space weather forecasting since they can observe both the solar eruptions and the source regions of the solar wind. Flat field processing is indispensable to remove the instrumental non-uniformity of a solar EUV imager in producing high-quality scientific data from original observed data. FengYun-3E (FY-3E) is a meteorological satellite operated in a Sun-synchronous orbit, and the routine EUV imaging data from the Solar X-ray and Extreme Ultraviolet Imager (X-EUVI) onboard FY-3E has the characteristic of concentric rotation. Taking advantage of the concentric rotation, we propose a post-hoc flat field measurement method for its EUV 195 Å channel in this paper. This method removes the small-scale and time-varying component of coronal activities by taking the median value for each pixel along the time axis of a concentric rotation data cube, and then derives the large-scale and invariable component of the quiet coronal radiation, and finally generates a flat field image. The flat field can be generated with cadences from hundreds of minutes (one orbit) to several days. Higher flat field accuracy can be achieved by employing more data. Further analysis shows that our method is able to measure the instrumental spot-like non-uniformity possibly caused by contamination on the detector, which mostly disappears after the in-orbit self-cleaning process. It can also measure the quasi-periodic grid-like non-uniformity, possibly from the obscuration of the support mesh on the rear filter. After flat field correction, these instrumental non-uniformities from the original data are effectively removed. Moreover, the X-EUVI 195 Å data after dark and flat field corrections are consistent with the 193 Å imaging data from the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory, verifying the suitability of the method. The post-hoc method does not occupy observation time, which is advantageous for space weather operations. Our method is not only suitable for FY-3E/X-EUVI but also a candidate method for the flat field measurement of future solar EUV telescopes.
Effect of Re and Ta on self-trapping of helium in tungsten: a first-principles calculation
Authors: Zhang Luyao , Wang Jiawei , Guo Yue , Zhong Guang , Zhang Zheng , Ren Fei , Xu Zongwei , Shao Jianxiong , Chen Lin , Chen Ximeng , Guo Yanling
Published: July 2022

Self-trapping may play an important role in helium radiation damage of W material in fusion reactors. But the effect of rhenium (Re) and tantalum (Ta) on the self-trapping process in the defect-free tungsten is not clear at present, which has been investigated by the first-principles calculation in this work. The results suggest that He can be trapped by other He atoms without prior defects in the presence of Re/Ta substitutional atom. The substitutional Re atom acts as a trap for the interstitial He clusters and enhances their nucleation, while the Ta atom repulses the large He clusters (n ⩾ 5) and weakens the cluster bonding, thus the growth of He clusters in the vicinity of Ta is not energetically favorable. Moreover, the critical content of He atoms that may trigger the trap mutation decreases when Re exists but increases when Ta exists. These results suggest Re can facilitate the growth of He clusters by self-trapping while Ta has the opposite effects.
Investigation of the structure and properties of aluminum-matrix composite coatings for tribotechnical purposes formed on steel substrates
Authors: Mikheev R S , Kalashnilov I E , Bykov P A , Kobeleva L I
Published: July 2022

The structure and properties of aluminum-matrix composite coatings for tribotechnical purposes, formed on steel substrates, have been investigated. Preliminarily, to limit the interaction between the materials of the substrate and the matrix of the composite material, i.e. iron and aluminum, an intermediate layer of pure aluminum was applied to the substrate surface by the explosion welding process. It is shown that the deposited composite coatings of Al-12Si + 10 wt.% SiC(40) are characterized by a uniform reinforcements distribution, and their adhesion strength values reach 66 MPa. According to the results of friction and wear tests under dry sliding friction conditions, it was determined that the manufactured samples have a 50% higher wear resistance compared to industrial bimetallic materials made of steel 20 with a B83 babbit coating, and their use in friction units will significantly expand the range of triboloading of the promising constructions.
Layout Green Logistics Moving Materials by Gravity
Authors: Alkhaleefah A S
Published: July 2022

The consumption of electricity in industry is receiving a lot of attention as electricity is one of the main drivers in the industry. We can make a huge savings in electricity by using gravity as we always strive for sustainability. Therefore, this paper aims to explore, as an empirical research, the relationship between the type of industry and the moving of materials by gravity, which is known as “green logistics”; using statistical techniques namely Pearson Chi-Square and Likelihood Ratio test. The theme of green logistics was chosen as one of the forms of sustainability.

i.e the use of gravity for handling materials during the manufacturing process, so that it does not consume any electrical energy, but rather moves materials or goods from one "working place" to the next using the force of inclination or humans. The research sample is the factories of the Kingdom of Saudi Arabia, specifically the plastic industries and the furniture industries, this is due to the appropriateness of the material for handling by gravity, moving materials or products regardless of their shape, size or weight. The research will also study the most prominent production stations in which gravity is used, such as packing, packaging, loading and unloading, and others. It is expected that the results of this research will lead to the proposal of some legislation, whether related to the construction of industrial facilities or manufacturing processes, so that these legislations can be adopted, at least in a gradual manner. This topic of research was chosen specifically in view of the modern global trend towards considering sustainability and extending its applications in most aspects of life, including the industrial sector, which consumes about 47% of primary energy. This means that reducing dependence on electricity in a country that accommodate nearly 8,000 factories will be a tangible impact on enhancing the concept of sustainability.
Assessment of air quality index (AQI) in Riyadh, Saudi Arabia
Authors: Hassan R , Rahman M , Hamdan A
Published: July 2022

Air pollution is increasingly becoming a main environmental matter in the world. It can impact public health, weather, and climate. Riyadh's air pollution poses significant environmental and health risks. The study aimed to analyze Riyadh's current and future air quality by using AQI. Main six air pollutants are considered, nitrogen dioxide (NO2), sulfur dioxide (SO2), particulate matter (PM), ground level ozone (O3), and carbon dioxide (CO2), carbon monoxide (CO). Eleven air quality stations located throughout Riyadh assess the concentration of six standard pollutants daily. A comparison of air quality in Riyadh was done at the local, regional, and international levels. Furthermore, diverse factors such as meteorological seasons, working periods, and the COVID-19 period are taken into account. Industrial emissions, as well as contributions from mobile sources and wind-blown dust, appear to be the principal pollutant sources affecting Riyadh. The measured air quality components for all contaminants were found to be below standard. PM poses the greatest damage to the city's human health of all the pollutants studied. It can be found in practically all locations of air quality stations, even though CO and O3 levels in the city are not at alarming levels.
Gaussian process regression model for the prediction of the compressive strength of polyurethane-based polymer concrete for runway repair: A comparative approach
Authors: Haruna S.I. , Zhu Han , Umar I.K. , Shao Jianwen , Adamu Musa , Ibrahim Yasser E.
Published: July 2022

Polyurethane (PU) composites have increasingly been used as construction materials to maintain civil engineering structures such as road pavement, runway, parking area, and floor systems in buildings. This study developed polyurethane polymer concrete (PC) mixtures by mixing aggregate-to-PU resin at 0.9: 0.1 and 0.85: 0.15 ratios by weight. The Machine Learning algorithms, including Gaussian Process Regression (GPR), Classification and Regression Tree (CART), and Support Vector Regression (SVR) model were employed to predict the compressive strength of PUPC mixtures as a repair material. The models were trained on the dataset of flexural strength (MPa), density (kg/m3), and PU composition (%), applied as input variables. The result revealed that the compressive stress-strain curves of PU-based polymer concrete exhibit linear elastic behavior under compression. The developed models demonstrate high prediction accuracy of PUPC’ strength. The Nash-Sutcliffe efficiency (NSE) was used to check the performance of each model, and the result obtained showed that the GPR model predicted the compressive strength with the highest accuracy with an NSE-values of 0.9619 and 0.9585 at the training and testing phase, respectively. The finding in this study could offer valuable insight into using these proposed models for compressive strength prediction of PU-based polymer concrete
Sustainable Solution for Deteriorated and Aged RCC Structures: A Review of Buildings, Bridges and Pavements
Authors: Alam M S , Arifuzzaman M. , Islam M K , Al-Fuhaid A F , Al-Mamun A
Published: July 2022

Sustainability is an important topic worldwide. The sustainable design will reduce the consumption of energy, water, land and raw materials. This ought to be taken into account when designing new structures and strengthening and renovating of existing deteriorated structures. This paper deals with the sustainable solution for the strengthening and renovating of the deteriorated or impaired structures. This is usually done through the use of FRP strips / sheets or bars that is bonded outside the member. Many researches have been conducted on this technique to observe its behaviour and ultimate strength. The materials used in research are steel, glass fibre reinforced polymer (GFRP), carbon fibre reinforced polymer (CFRP), aramid fibre reinforced polymer (AFRP) sheets or bars. These were used as side bonding, U-jacketing and wrapping of the members. A significant improvement in strength was observed in the strengthened members. Accordingly, these techniques have been suggested as a sustainable solution. Based on the investigations, different countries propose different design codes and standards. Some of them provide reliable predictions, but more research is needed for an accurate and consistent predictive model.
Use of Waste Ferrochrome Slag as a Sustainable Building Material for Extreme Environments
Authors: Sohel K M A , Al-Jabri K , Islam M Z , Al-Shereiqi A A R
Published: July 2022

Ferrochrome slag is an industrial by-product material extracted during the production process of ferrochrome alloy, which is mostly used in the stainless steel industry. Large quantities of ferrochrome slag are generated annually from the steel companies in the Sultanate of Oman. The vast majority of the quantities are not used in any application and are disposed of without being reused, posing a threat to the local environment. There has been an increasing emphasis in recent years on the use of different waste materials as construction materials, which may help to alleviate environmental and ecological challenges. The physical, mechanical, chemical and thermal properties of ferrochrome slag (FCS) are favorable to be used in concrete for extreme environments such as high temperature and corrosive environments. In this study, the effect of using ferrochrome slag as a substitute for natural fine and coarse aggregates (incremental range from 25% to 100%) on the strength of concrete at elevated temperatures (ranging from 200°C to 1000°C with 200°C intervals) was investigated. Acid resistance of FCS concrete was also investigated. It is found that the inclusion of FCS enhances the compressive strength of the concrete. The thermal properties of FCS aggregate positively affect the fire resistance of the FCS concrete. The FCS concrete shows better performance in an aggressive environment than conventional concrete. Therefore, waste ferrochrome slag may be an alternative option to be used as green coarse and fine aggregates in the production of concrete.
Study on Wetted Soil Geometry of a Negative Pressure Irrigation (NPI) System
Authors: Moniruzzaman S. M. , Fukuhara Teruyuki , Arifuzzaman Md. , Rahman Muhammad
Published: July 2022

The limited water resource is a main constraint on agricultural production in arid and semi-arid regions like Saudi Arabia. The Negative Pressure Irrigation (NPI) is one of the attractive irrigation systems since it consumes less water, leads irrigated water down up to root zone, minimizes evaporation and prevents deep percolation than other traditional irrigation systems. The aim of this paper is to get information on the soil water dynamics, which is very essential for the design and operation of the NPI system. With this view, the water balance experiment was carried out in the NPI system for different time intervals for three different negative pressures ( Pn
= -0.02m, -0.07m and -0.10m). After finishing the experiment, the dry soil was removed from the column to measure the configuration of wet soil. This geometry of wetted soil represents the soil water dynamics and the wetted soil volume represents the water stored in soil at different negative pressures and elapsed time. A good relationship was obtained between the wetted soil geometry, time and negative pressure. This study reveals that for a certain negative pressure and time interval, the depth, width and volume of wetted soil can be predicted.
Compressive Strength Development of Dune Sand Reactive Powder Concrete (RPC) Under Different Curing Conditions
Authors: Ahmed S , Abed F , Mannan M A
Published: July 2022

Reactive powder concrete (RPC) is a special type of concrete with remarkable properties, particularly compressive strength. Some of its main disadvantages include its high cement and SF content, fine quartz with a preferred size of 150 μm - 600 μm, and low water-to- binder ratio. These characteristics increase the cost of RPC production and affect sustainable development. Because of this, researchers have resorted to exploring substitutes to cement and quartz to produce an eco-friendlier type of RPC. Accordingly, this research aims to study the compressive strength development of RPC prepared with dune sand and supplementary cementitious materials (SCM). Three main factors were investigated including 1) replacing cement with 30% ground granulated blast furnace slag (GGBS), 2) using ternary blends of GGBS and fly ash (FA) in RPC, and 3) applying 100°C hot air curing (HAC) to RPC. Overall, the results showed that the compressive strength of HAC and water cured specimens exceeded 120 MPa after 12 hours and 28 days, respectively. Moreover, the compressive strength development of the mixes incorporating SCM was slower than that of the control mix incorporating cement only under HAC conditions.
A Comparative Study On The Seismic Performance Of Multi-storey Buildings With Different Structural Systems
Authors: Ahmed Mohammed Mudabbir , Manzoor Khaja Musab
Published: July 2022

The increasing need of shelter in urban cities due to overpopulated spaces and land inadequacy has forced people to limit their needs and spaces. High-rise buildings are the best solution for providing people space for living and to work on, as the buildings are getting higher and slender, they are exposed to different loading condition, which leads the building to experience higher lateral deformations. With the help of different structural systems, the lateral stiffness of the buildings can be improved, there are many structural systems introduced for the high-rise structures which can provide the buildings adequate strength and stability against lateral loading. This paper examines behaviour of Special Moment Resisting Frame System with shear wall, Outrigger Core Belt Truss Structural System and Braced Frame System on a 30 storey building under worst seismic conditions in India i.e. Zone V. To understand effectiveness of the structural systems subjected to lateral loads, three different structural system are modelled using 3D finite element software ETABS 2018, all the models are subjected to the same loading conditions with same geometrical dimension and typical storey height. Comparison is examined on the basis of different parameters like Modal Mass Participation, Base shear, storey shear, Time period, Lateral displacement, storey drift, storey stiffness, and performance points. It was observed by the dynamic analysis method i.e., response spectrum analysis, and non-liner static analysis, the parameters which were compared between three structural system observed that building with outrigger core belt truss system performs better than Special Moment Resisting Frame + Shear Wall and Braced Frame Structural System.
Development of green and sustainable ultra-high-performance concrete composite reinforced with date palm fibers
Authors: Althoey Fadi , Hakeem Ibrahim Y.
Published: July 2022

In a sustainable approach, it is essential to reduce the volume of agricultural waste materials in order to minimize environmental and health concerns. To pursue this goal, agricultural wastes, mainly date palm fibers (DPFs), was used as a partial replacement of conventional steel fibers to produce ultra-high-performance concrete (UHPC). The UHPC has been used to describe a steel-fibers-reinforced cementitious composite with a very low water-binder ratio. It is one of the most significant breakthroughs in concrete technology in the 20th century due to its outstanding mechanical performance, such as compressive strength over 150 MPa and flexural strength over 30 MPa. The cost of UHPC is known to be significantly higher compared to ordinary reinforced concrete because it requires large quantities of steel fibers. This paper aims to study the feasibility of utilizing DPFs as a partial replacement of steel fibers to produce green, low-cost and sustainable UHPC. The process of extraction and treatment of the DPFs before incorporating it into the mix design was discussed. Several concrete samples were prepared with different weight percentages of DPFs as a partial replacement of steel fibers (from 0% to 25 wt.%). Compression strength, flexural strength, water absorption, and fresh/hardened densities were experimentally investigated. The morphology and the bonding interface between the fibers and cementitious composite were characterized by scanning electron microscopy (SEM). The results reveal that the DPFs has the potential to be utilized to produce UHPC with comparable performance to the traditional UHPC that is normally reinforced with steel fibers.
Stability analysis of an unsaturated pond ash slope subjected to rainfall
Authors: Srikanth Chitti Satya Sundara Uday , Ramaiah B J , Murali Krishna A
Published: July 2022

In the present study, stability analysis of an unsaturated homogenous pond ash slope subjected to rainfall using the limit equilibrium method based n Bishop and Morgenstern-Price methods under steady-state seepage and transient seepage conditions was carried out. Seepage and stability analyses were carried out using SEEP/W and SLOPE/W models, respectively. The factor of safety (FoS) in the case of the unsaturated pond ash slope was observed to be higher than the saturated slope. The effect of slope geometry, rainfall intensity, anisotropy in permeability, and provision of drains on slope stability were investigated. It is observed that with an increase in rainfall infiltration, there was a tendency of surficial failure when the rate of infiltration is higher than the saturated permeability in the unsaturated pond ash slope. The study assumes importance related to the stability of slopes constructed with coal ash in the context of ever-growing requirements of electricity in the country, slope failures due to extreme weather events associated with climate change, and the requirement of sustainable alternatives, theories, and technologies to tackle the coal ash waste produced.
Designing the temporary dental clinic in the Covid-19 global pandemic
Authors: Rahmayati Y , Vanini F , Rahmayani L , Hendarti R , Aghamdi W , Andriany P , Sundari I , Novita C F , Sofya P A
Published: July 2022

Covid-19 pandemic has directed hospitals to concentrate services for patients who are positive or still in undefined status. Some countries are even forced to build temporary structures or utilize multifunctional buildings such as sports/public halls. On the other hand, hospitals still have to keep performing other routine services and this becomes a challenge for them. When global attention nowadays focuses more on how hospitals serve the Covid-19 cases, this research proposes another side of healthcare service needed by people in the pandemic, which is the dental clinic. The spread of Covid-19 through droplets puts both dental patients and practitioners at risk target of Covid-19 transmission. Therefore, particular standards and protocols are mandatory to be deployed. A prototype design of the temporary dental clinic is the main output from this research. The main objective is to provide service for the community without being afraid of contracting the pandemic as the clinic will be isolated from the regular hospital buildings. To achieve this objective, this research employed three approaches for the methodology. It was started with the desk study to review references on recent technology of temporary building structures. Followed by the online questionnaire using the Google platform distributed to 206 registered dental practitioners in Aceh, in collaboration with the Indonesian Dental Association, Aceh Province, Indonesia. The questionnaire collected the data related to the needs, standards, procedures, and dental service protocols under the Covid-19 pandemic as the main reference for the design process. The last approach was gathering feedback from dentists and international architects who are experts in building science and technology. This was done through a series of pre-design reviews. This research has a high degree of urgency globally, including Saudi Arabia, which is also impacted by the Covid-19 pandemic. It is also in line with Saudi Vision 2030 to enhance the standard quality and sustainability of healthcare services. The prototype design proposed in this research does not only contribute to the Covid-19 pandemic in particular but also post-Covid scenarios or other possible global pandemics in the future.
Effects of Uniform Load on Externally Post-tensioning Composite Beams under Multiple Degrees of Shear Connection
Authors: Hassanin A I , Shabaan H F
Published: July 2022

Composite beams (steel and concrete) are used widely as the main structural elements in flexure in bridges and buildings. Such structures' design life would be decreased if the loads increased or if environmental deterioration could occur. Such modifications can reduce the strength of these members and therefore need to be considered for replacement or retrofitting.The current study presents an evaluation of the effect of shear connection with its different degrees from partial to full for the composite beams strengthened with post-tensioning tendons. It is known by design that the use of partial shear connection in composite beams requires that the sliding capacitance of the shear connectors shouldn’t be less than the maximum slip so that the composite section can reach the ultimate design load. The degree of shear connection over which the composite section is designed, as well as the span length of the beam, are the most important factors governing the maximum slip limit. This study was performed using numerical modelling by the finite element analysis method to simulate the bending behaviour of composite steel beams under uniform loading cases which were strengthened with three shapes of tendons profiles. The results of two finite element models have been compared with experimental results obtained from previous literature related to the same topic. This comparison was made to ensure the efficiency, effectiveness, and accuracy of the model used, using ANSYS Workbench Software.
Assessing Seawater Desalination using Reverse Osmosis and Multi-effect Distillation for Kuwait using Life Cycle Assessment: fossil fuels versus solar power
Authors: Aljuwaisseri A , Aleisa E , Alshayji K
Published: July 2022

Sustainable water production is one of the top five challenges facing humanity within the upcoming decade, for arid regions the situation is aggravated. Countries worldwide are urged to balance of the SDG 6 (clean water and sanitation), SDG 7 (affordable and clean energy) to contribute to SDG 13 (climate action). This research evaluates seawater desalination in arid regions using multi-effect distillation (MED) and seawater reverse osmosis (SWRO) using fossil fuels versus solar power versus solar collector system (SCS) and and photovoltaic (PV). Four alternatives were investigated MED (NG), MED (SCS), SWRO (NG) and SWRO (PV) using life cycle assessment (LCA) to desalinate one cubic meter of seawater using a second-order boundary (i.e., cradle to gate) in which the operational parameters include: energy, materials, chemicals and additives in accordance with ISO 14040/4. The foreground data is based on field data collection that considers water intake characteristics: salinity and turbidity. The background inventories are based on Ecoinvent database v.3. The life cycle impact assessment is based on midpoint analysis using ReCiPe midpoint (H) v1.10. The results indicates that the primary fuel exergy and the allocation of energy in water electricity co-generation is the defining factor.
Retrofitting Old Silk Factory in Valmadrera, Italy with Insulated Envelope Solutions.
Authors: Rauf K , Paraschiv R
Published: July 2022

Building industry is responsible for almost 50% of the world’s total energy demand. It takes more energy to operate buildings than it takes to run the manufacturing or transportation industry. In the drive for climate change, a lot of work is being done by policy makers for making new projects better aligned with environmental and energy conservation goals. It is not enough to only focus on improving the climate response of new construction. Work also needs to be done on improving the energy performance of existing building projects which will in turn, further reduce the CO2 footprint of the building operations industry. One way to reduce the energy consumption of existing buildings, is to add insulation to façade elements during building retrofitting projects. The purpose of this research is to shed light on probable options and benefits for adding insulation to traditional envelopes. This will enhance the operating capacity of buildings without the need for demolition or re-construction. This project demonstrates the energy efficient retrofitting of an old silk factory in the historic city of Valmadrera, Italy to act as a prototype project testing suitable options for adding insulation to existing structural systems. One of the biggest challenges for this type of upgrade is the porous nature of the existing building material and how it conflicts with the hygroscopy of synthetic insulation materials. The research suggests the use of organic insulating materials for the envelope elements. At the same time it also offers valuable suggestions for future explorations. This research has a high impact value globally, due to the vast treasure of historical architecture buildings which need to be preserved, but also need improvement in terms of their technological performance. Furthermore, it holds strong relevance for the Saudi Vision 2030 because preserving local architectural practices, materials and techniques is a significant part of the national motivation to preserve Saudi cultural identity.
Optimizing Parameters of Artificial Intelligence Deep Convolutional Neural Networks (CNN) to improve Prediction Performance of Load Forecasting System
Authors: Butt F M , Hussain L , Jafri S H M , Lone K J , Alajmi M , Abunadi I , Al-Wesabi F N , Hamza M A
Published: July 2022

Load Forecasting is an approach that is implemented to foresee the future load demand projected on some physical parameters such as loading on lines, temperature, losses, pressure, and weather conditions etc. This study is specifically aimed to optimize the parameters of deep convolutional neural networks (CNN) to improve the short-term load forecasting (STLF) and Medium-term load forecasting (MTLF) i.e. one day, one week, one month and three months. The models were tested based on the real-world case by conducting detailed experiments to validate their stability and practicality. The performance was measured in terms of squared error, Root Mean Square Error (RMSE), Mean Absolute Percentage Error (MAPE) and Mean Absolute Error (MAE). We optimized the parameters using three different cases. In first case, we used single layer with Rectified Linear Unit (ReLU) activation function. In the second case, we used double layer with ReLU – ReLU activation function. In the third case, we used double layer with ReLU – Sigmoid activation function. The number of neurons in each case were 2, 4, 6, 8, 10 and 12. To predict the one day ahead load forecasting, the lowest prediction error was yielded using double layer with ReLU – Sigmoid activation function. To predict ahead one-week load forecasting demands, the lowest error was obtained using single layer ReLU activation function. Likewise, to predict the one month ahead forecasting using double layer with ReLU – Sigmoid activation function. Moreover, to predict ahead three months forecasting using double layer ReLU – Sigmoid activation function produced lowest prediction error. The results reveal that by optimizing the parameters further improved the ahead prediction performance. The results also show that predicting nonstationary and nonlinear dynamics of ahead forecasting require more complex activation function and number of neurons. The results can be very useful in real-time implementation of this model to meet load demands and for further planning.