bluuebunny/crossref_metadata_2025 huggingface dataset:
Swift heavy ion irradiation effect on structural, morphological and mechanical properties of Zr70Ni30 metallic glass
Authors: Boukhemkhem Wafa , Izerrouken Mahmoud , Ghidelli Matteo , Pardoen Thomas , Sari Ali , Yazid Khereddine Abdel , Meftah Ali
Published: July 2023

Metallic glass films are considered for coating applications in the nuclear field owing to their advantageous performances. However, the response to irradiation remains to be more thoroughly characterized. Zr70Ni30 metallic glass films were irradiated by 0.71MeV/u129Xe23+ ions in the fluence range from 5 × 1012 to 8 × 1013 ions cm−2. The structural, morphological, and mechanical properties were determined using grazing incidence X-ray diffraction (GI-XRD), atomic force microscopy (AFM), and nanoindentation for the as-deposited and irradiated samples. The Xe ion induced surface smoothening, thereby increasing the corrosion resistance. One-dimensional power spectral density of the AFM data of irradiated film demonstrated that the irradiation-induced evolution of the surface morphology could be attributed to a transition between viscous flow and the evaporation-condensation mechanism. The amorphous structure was unaffected after irradiation up to a fluence of 8 × 1013 ions cm−2. Nanoindentation revealed first a softening as the fluence increases up to 4 × 1013 ions cm−2, reflecting the creation of free volume defects. Then the hardness and Young’s modulus slightly increase when reaching 8 × 1013 ions cm−2. Moreover, at a critical dose of 0.008 dpa, the hardness is found to increase. Moreover, the calculation of the inelastic thermal spike model reveals the formation of the track with a radius of 7 nm.
The hidden quantum origin of gauge connections
Authors: Patrascu Andrei T
Published: July 2023

A fibre bundle viewpoint of gauge field theories is reviewed with focus on a possible quantum interpretation. The fundamental quantum properties of non-separability of state spaces is considered in the context of defining the connection on the fibre bundle, leading to an application of the quantum principles to the geometrical and topological definition of gauge theories. As a result, one could justifiably ask oneself if all interactions of the standard model, and perhaps even classical gravity have some quantum component after all. I employ a standard fibre bundle approach to introduce gauge theories, albeit it is known that a quantum bundle exists, simply because the main scope is to show that in the usual way in which we formulate classical gauge theories one can find quantum aspects that have been unknown until now. In a sense, I will try to justify the assessment that if we are to allow for gauge fields and parallel transport, we may have to allow at least some level of quantumness even in our classical gauge theories. The main statement is that propagation of interactions in spacetime is a quantum phenomenon. After writing the first draft of this article I noticed Y Shen C. Rosales-Guzman 2022Laser & Photonics Reviews,16,2100533 where the authors device entanglement of what they call ‘classical light’. This experiment supports my theoretical developments with the distinction that I interpret such phenomena also as fundamentally quantum. The distinction comes from the fact that the quantum nature of the experiments is manifested in a different way. My view on this is that there is no purely classical reality, no matter what the scale is at which we consider the description. I also discuss the fact that observing a quantum nature of ‘classical’ light propagation would amount to the requirement of modifying the causal structure defined in terms of the speed of light in a vacuum, on stronger grounds, based on the quantum interpretation of gauge connections.
Constraints on the parameterized deceleration parameter in FRW universe
Authors: Chaudhary Himanshu , Bouali Amine , Debnath Ujjal , Roy Tanusree , Mustafa G
Published: July 2023

Confirmation of accelerated expansion of the Universe probed the concept of dark energy theory, and since then, numerous models have been introduced to explain its origin and nature. The present work is based on reconstructing dark energy by parametrization of the deceleration parameter in the FLRW universe filled with radiation, dark matter and dark energy. We have chosen some well-motivated parametrized models 1-3 in an attempt to investigate the energy density in terms of deceleration parameters by estimating the cosmological parameters with the help of different observational datasets. Also, we have introduced a new model 4 for the parametrization of the deceleration parameter. Then we analyzed the cosmography parameters using the best-fit values of the parameters. Using the information criteria, we have examined the viability of the models.
Data augmentation and hybrid feature amalgamation to detect audio deep fake attacks
Authors: Chakravarty Nidhi , Dua Mohit
Published: July 2023

The ability to distinguish between authentic and fake audio is become increasingly difficult due to the increasing accuracy of text-to-speech models, posing a serious threat to speaker verification systems. Furthermore, audio deepfakes are becoming a more likely source of deception with the development of sophisticated methods for producing synthetic voice. The ASVspoof dataset has recently been used extensively in research on the detection of audio deep fakes, together with a variety of machine and deep learning methods. The proposed work in this paper combines data augmentation techniques with hybrid feature extraction method at front-end. Two variants of audio augmentation method and Synthetic Minority Over Sampling Technique (SMOTE) have been used, which have been combined individually with Mel Frequency Cepstral Coefficients (MFCC), Gammatone Cepstral Coefficients (GTCC) and hybrid these two feature extraction methods for implementing front-end feature extraction. To implement the back-end our proposed work two deep learning models, Long Short-Term Memory (LSTM) and Gated Recurrent Unit (GRU), and two Machine Learning (ML) classifier Random Forest (RF) and Support Vector Machine (SVM) have been used. For training, and evaluation ASVspoof 2019 Logical Access (LA) partition, and for testing of the said systems, and ASVspoof 2021 deep fake partition have been used. After analysing the results, it can be observed that combination of MFCC+GTCC with SMOTE at front-end and LSTM at back-end has outperformed all other models with 99% test accuracy, and 1.6 % Equal Error Rate (EER) over deepfake partition. Also, the testing of this best combination has been done on DEepfake CROss-lingual (DECRO) dataset. To access the effectiveness of proposed model under noisy scenarios, we have analysed our best model under noisy condition by adding Babble Noise, Street Noise and Car Noise to test data.
An electromagnetic-thermal-mechanical analysis model for high temperature superconducting magnets
Authors: Yang Zhixing , Ren Li , Xu Ying , Shi Jing , Duan Pu
Published: July 2023

High temperature superconducting magnets are the core component of superconducting power devices, and their stability is the key factor that restricts the safe operation of superconducting power devices. In order to accurately and effectively evaluate the stability of superconducting magnets during operation, an electromagnetic-thermal-mechanical numerical simulation method for high temperature superconducting magnets is studied in this paper. Based on the model, the 150 kJ SMES magnet as case is studied, the magnetic field and current density distribution are solved during its operation, and its temperature rise, AC loss and stress analysis of the magnet are achieved. In addition, this work further analyses the critical current degradation of superconducting tapes in the 150 kJ HTS magnet under multi-field coupling, the dangerous region in operation is obtained and suggestions are put forward to avoid quench. The electromagnetic-thermal-mechanical model may provide an appropriate stability assessment with rapid and real-time calculations for high temperature superconducting magnets.
The effect of Cu ions concentration on electrochromic properties of Cu embedded PANI thin films
Authors: Esmaeilizadshali Hossein , Nikfarjam Alireza , Kordlar Amir Ghasemi
Published: July 2023

In this paper, copper salt (CuSO4.5H2O) has been used to improve electro-optical performances of PANI electrochromic layers including color switching rate (from transparent to colored state) and stability. For this purpose, the PANI solution was chemically prepared in the presence of different amounts (0.018, 0.03, 0.25, 0.5 and 2.5%w) of copper ions concentration by electrodeposition technique on a fluorine doped tin oxide (FTO) glass, which was used as a transparent conductive electrode and substrate. Finally, the five PANI/Cu samples were characterized and compared with pure PANI electrochromic layer. As a result, with cyclic voltammetry analysis and photospectroscopy, in the most optimal amount of copper (0.03%w) the optical contrast of the Cu embedded PANI electrochromic layer enhanced from 15% to 52.5%, its coloring time improved from 3 s to 1.3 s and its stability was the best.
Micro-arcsecond Astrometry Technology: Detector and Field Distortion Calibration
Authors: Shao Michael , Zhai Chengxing , Nemati Bijan , Hahn Inseob , Trahan Russell , Turyshev Slava
Published: July 2023

Microarcsecond (μas) astrometry is an indispensable technique to detect earth-like exoplanets, fully characterize exoplanetary orbits, and measure their masses—information critical for assessing their habitability. Highly accurate astrometric measurements can also probe the nature of dark matter, the early universe, black holes, and neutron stars, thus providing unique data for new astrophysics. This paper presents technologies of calibrating detectors and field distortions for achieving narrow field μas relative astrometry with a focal plane array detector on a 6 m telescope.
Decoding articulatory and phonetic components of naturalistic continuous speech from the distributed language network
Authors: Thomas Tessy M , Singh Aditya , Bullock Latané P , Liang Daniel , Morse Cale W , Scherschligt Xavier , Seymour John P , Tandon Nitin
Published: July 2023

Objective. The speech production network relies on a widely distributed brain network. However, research and development of speech brain–computer interfaces (speech-BCIs) has typically focused on decoding speech only from superficial subregions readily accessible by subdural grid arrays—typically placed over the sensorimotor cortex. Alternatively, the technique of stereo-electroencephalography (sEEG) enables access to distributed brain regions using multiple depth electrodes with lower surgical risks, especially in patients with brain injuries resulting in aphasia and other speech disorders. Approach. To investigate the decoding potential of widespread electrode coverage in multiple cortical sites, we used a naturalistic continuous speech production task. We obtained neural recordings using sEEG from eight participants while they read aloud sentences. We trained linear classifiers to decode distinct speech components (articulatory components and phonemes) solely based on broadband gamma activity and evaluated the decoding performance using nested five-fold cross-validation. Main Results. We achieved an average classification accuracy of 18.7% across 9 places of articulation (e.g. bilabials, palatals), 26.5% across 5 manner of articulation (MOA) labels (e.g. affricates, fricatives), and 4.81% across 38 phonemes. The highest classification accuracies achieved with a single large dataset were 26.3% for place of articulation, 35.7% for MOA, and 9.88% for phonemes. Electrodes that contributed high decoding power were distributed across multiple sulcal and gyral sites in both dominant and non-dominant hemispheres, including ventral sensorimotor, inferior frontal, superior temporal, and fusiform cortices. Rather than finding a distinct cortical locus for each speech component, we observed neural correlates of both articulatory and phonetic components in multiple hubs of a widespread language production network. Significance. These results reveal the distributed cortical representations whose activity can enable decoding speech components during continuous speech through the use of this minimally invasive recording method, elucidating language neurobiology and neural targets for future speech-BCIs.
Treatment of greywater by adsorption and coagulation with Hibiscus Sabdariffa as the natural coagulant
Authors: Ahmad M. , Ismail N , Yoon L W
Published: July 2023

Greywater refers to wastewater from showers, baths, basins and washing machines. Recycled greywater can be used for crops irrigation, toilet flushing, and other activities that does not require fresh water. Coagulation is an effective, simple, and cheap process to treat greywater with the use of coagulants. The studies show that the use of chemical coagulants pose threat to the environment, produce large amount of sludge and have severe effect on human health. This study uses Hibiscus Sabdariffa seeds as natural coagulant, as they are biodegradable, non-toxic, and safe for human health. The seeds of Hibiscus Sabdariffa are usually discarded, thus using them as natural coagulants makes it cost-effective. Another process of adsorption was also studied in this work due to its effectiveness in treating wastewater. Activated carbon have been studied as an adsorbent due to its low-cost and sustainability. The aims of this paper are to investigate the performance of the seeds and adsorbent by differing pH, coagulant dosage, and adsorbent dosage. Jar test was carried out by varying pH of 2-12, coagulant dosage of 20-120 mg/L and adsorbent dosage of 0.5-5g. The process involved rapid mixing for 4 minutes, slow mixing for 25 minutes and 30 minutes of sedimentation time. By carrying out the experiment, it was found out the seeds of Hibiscus Sabdariffa showed best performance at pH 2, coagulant dosage 20 mg/L with the turbidity removal and COD removal of 91.3% and 43%, respectively. For the process of adsorption, highest turbidity and COD removal were determined to be 98.6% and 61.6% respectively with the pH 2 and adsorbent dosage of 3g. The combined process of adsorption-coagulation shows best performance at pH 2, coagulant dosage 4 mg/L and adsorbent dosage of 1.6g with the turbidity and COD removal of 98.3% and 85% respectively. This study shows the potential in Hibiscus Sabdariffa seeds and activated carbon to treat greywater for reuse.
Synthesis of tunable hydrophilic deep eutectic solvent for the extraction of antioxidants from Salvia officinalis L.
Authors: Ghanem N , Chua B L , Albalushi A S A
Published: July 2023

The leaves of Salvia officinalis L., a plant known for its high antioxidant content, were selected as the focus of this research. This research aimed to evaluate the antioxidant activity of sage leaves extract by varying the hydrophilic deep eutectic solvents (DESs) compositions and molar ratios. The hydrophilic DESs were synthesized using the heating method with diverse combinations of DES, including lactic acid (LA), oxalic acid (OA), succinic acid (SA), and ethylene glycol (EG) as hydrogen bond donors (HBDs) and choline chloride (ChCl) as the sole hydrogen bond acceptor (HBA) with varied molar ratios of HBA to HBD (1:1, 1:2, and 2:1). The antioxidants were extracted using ultrasound-assisted extraction method at 70°C of extraction temperature, 30 mins of sonication time, and 1:30 g/mL of solid-solvent ratio. The DES extraction efficiency was evaluated based on the antioxidant scavenging abilities measured by α, α-diphenyl-β-picrylhydrazyl (DPPH) free radical scavenging assay. The results revealed that the ChCl-OA showed the highest antioxidant activity (67.660 μg/mL), followed by ChCl-EG (52.327 μg/mL) and ChCl-LA (33.116 μg/mL) with molar ratios of 1:1, 1:2 and 1:2, respectively. As conclusion, ChCl-OA with molar ratio of 1:1 exhibited the highest extraction efficiency (77.259%) as compared to the other DES combinations using 70% of methanol (v/v).
A simple speed bump energy harvester
Authors: Teng Janessa Hui Mann , Tien Douglas Tong Kum
Published: July 2023

As the nation progresses, energy demand increases. The generation of electricity in Malaysia is currently from natural gas, crude oil and petroleum, coal and coke, hydro and other renewable energy sources. Depletion of non-renewable energy sources and excessive carbon emissions are significant concerns. Any effort to mitigate, however small, is worth considering. In this study, energy harvesting from speed bumps is proposed and a roller speed bump energy harvester (SBEH) was conceived. From theoretical analysis, the roller SBEH can produce a theoretical power output of 1632.92 W when a car of 850 kg crosses the speed bump with a speed of 10 km/h. The primary driving force for roller SBEH was velocity and the secondary contributor was the weight of the vehicle. Greater speed and mass results in greater energy harvest. Future work will look further into its feasibility, examine the challenges of installation, perform size optimization and a proof-of-concept prototype.
Development of a low-cost non-destructive test system for measurement of elastic modulus
Authors: Chio W H , Amares S
Published: July 2023

Conventional measurement processes to determine elastic modulus of samples such as tensile or flexural test and bending test are typically unidirectional and destructive in nature for the measured samples. The industrial grade and commercially available Non-Destructive Test (NDT) measurement instrument based on the impulse excitation technique is meanwhile expensive. This project involves designing and developing a low-cost NDT system for the measurement of elastic modulus based on the impulse excitation technique. Secondly, it is to compare the performance of the measurement system with the tensile test. The performance of the NDT prototype will be put to test by using different type of specimens such as aluminium alloy, copper, brass, and carbon steel. Each type of specimen will carry be tested three times to get the average of the data. After all the data collection of the NDT measurement system, the tensile test will be carried out. A comparison for the measurement of the elastic modulus will be conducted between the NDT system, tensile test, and theoretical results. The expected outcome for this project is to develop a NDT for the measurement of the elastic modulus. This project also aims to reduce the industrial waste, reduce the cost of the sample test and maintain the accuracy and the performance of the NDT system compared with the tensile test.
Investigation of the effect of nose shape and geometry at supersonic speeds for missile performance optimisation
Authors: Kim B K , Al-Obaidi A S M
Published: July 2023

This paper investigated and analysed the influence of the missile nose shapes and geometry on the drag force coefficients at supersonic Mach numbers ranging from 2 to 5. The nose shape investigation includes a pointed cone, pointed ogive, and blunt cone with a constant length and diameter of cylindrical afterbody. Subsequently, the nose length was manipulated to investigate how the nose geometry with different fineness ratios affected each drag component. The drag force coefficient and its components were determined using a program called MATLAB_Aerody, in which a semi-empirical approach was implemented for the calculations. The program was validated against the semi-empirical results with existing theoretical and experimental results. The comparison showed a maximum error of 3.6%. The results of the nose shape analysis show that a sharper and more slender nose with a pointy tip produces a minimal drag. Nose bluntness, however, creates considerable additional drag force due to a higher wave drag coefficient by forming detached or bow shock waves. At supersonic speeds, increasing the fineness ratio significantly reduces the drag force by drastically decreasing the wave drag coefficient with a marginal increase in the skin friction coefficients. However, the results show an insignificant additional gain for the skin friction drag and a reduction in the wave drag coefficient when the nose has a fineness ratio beyond 4.5. Furthermore, the results from both analyses show that the base drag coefficient is invariant with the nose shape and the fineness ratio. Therefore, a better missile performance can be achieved with a sharper and more slender nose shape with a higher fineness ratio.
Fabrication of hydrogel controlled-released Phosphorus encapsulated in starch-polyvinyl alcohol film
Authors: Selapa Sivashanggary , Phang Siew Wei , Shuib Anis Suhaila , Tee Jen Looi
Published: July 2023

Traditional soluble phosphorous(P) fertilizers can easily leach into water systems causing water eutrophication, a major environmental problem caused by an excess release of nutrients. Controlling the release of P in response to the plant demand could reduce fertilizer’s losses and also reduce environmental pollution. This study establishes a concept of controlled release fertilizer, in which a hydrogel fertilizer film is fabricated by incorporating starch, polyvinyl alcohol and ammonium dihydrogen phosphate fertilizer which tend to immobilize the release of phosphate ions and accelerate responsively their release rate in the presence of water. The experiment aims to study the effect of incorporating Starch, and Polyvinyl alcohol (PVA) to Ammonium Dihydrogen Phosphate fertilizer by varying the composition of PVA-Starch-Ammonium Dihydrogen Phosphate and preparing the films through solution casting method. FTIR is being used to investigate the effect of Starch, PVA, and Ammonium Dihydrogen Phosphate composition on the intermolecular bonding of the fabricated film. A total of 10 samples with different material composition is prepared and the intermolecular bonding between this composition is being compared with that of pure starch, pure PVA and pure Ammonium dihydrogen phosphate fertilizer. The FTIR peak will reveal evidence of hydrogen bonding between phosphate molecules and the functional group of polymer molecules as well as showed all the characteristics band of Starch, PVA and Ammonium Dihydrogen Phosphate. The varying formulation of film corresponded to varying intensity of peak and also stretching vibrations.
Automated Parcel Loading-Unloading Mechanism Design for Delivery UAV
Authors: Eu Kwok Quan , Phang Swee King
Published: July 2023

Unmanned Aerial Vehicle or UAV has evolved rapidly because of improved regulations and advancement in technology. During the COVID-19 pandemic, delivery UAVs were utilized more often than ever to deliver medical supplies, as well as parcels. Delivery UAVs work by collecting the goods and keeping it in a designated holder, which it then navigates through an area and dropping it off at the receiving point. The main factors that are considered for the design of a delivery UAV mechanism includes size and weight of parcels, security and the efficiency of loading and unloading parcels. The drop-box mechanism takes in the factors contributing to existing delivery UAV mechanisms and provides a solution that can overcome most of these concerns. The mechanism was designed through SOLIDWORKS software and 3D-printed. With the help of SOLIDWORKS, an analysis was performed, and it was concluded that the mechanism could handle a maximum of 2kg. Aside from that, the mechanism drops off parcels automatically and encourages contactless delivery.
A study on transfer function to estimate the central aortic blood pressure waveform
Authors: Leonard Batende Vwikalo , Sooriamoorthy Denesh
Published: July 2023

Noninvasive measurement of the central aortic blood pressure has become an important technique that has generated a lot of interest around the medicine industry because it can estimate the central aortic blood pressure waveform without inserting a pressure-sensing catheter into the ascending aorta. The accuracy of noninvasive estimation of aortic hemodynamics and cardiac contractility is still debatable in noninvasive measurement of the central aortic blood methods. The objective of this project is to investigate the transfer functions available for converting radial blood pressure waveforms to central aortic blood pressure waveforms. In this project, three different transfer functions will be investigated which are The Generalized Transfer Function, N-Point Moving Average and Adaptive Transfer Function in order to recommend the effective method in terms of accuracy. The study methodology will be conducted through the software MATLAB R2021b. The investigation of these three methods will be conducted with data collected from virtual subjects from the HaeMod database. The Generalized transfer function, N-Point Moving Average and Adaptive Transfer Function will be coded, evaluated, and analyzed as part of the methodology. The determination of the most effective method among the three transfer functions will be attributed according to output comparison of Systolic peak differences, the RMSE and the MAPE between the estimated central aortic blood pressure and the measured central aortic blood pressure.
New Dynamic Time-of-Use Tariff For Islanded Microgrid System With High Penetration of Renewable Energy
Authors: Nazar J. , Jamian J.J. , Baharudin M.A. , Syed Nasir S.N.
Published: July 2023

This paper proposes a dynamic time-of-use (d-TOU) tariff scheme for microgrid (MG) systems in islanded mode. The main problem for the islanded MG is the high cost of electricity, and the output from renewable energy is uncontrollable compared to the traditional grid. Therefore, this paper focuses on developing a suitable tariff scheme that provides reliability and financial benefits for both utility and customer. The time zone energy prices based on the Levelized Cost of Energy (LCOE) are introduced for islanded MG. The results show a contradiction between islanded MG with the standard traditional power generation TOU. Even though the LCOE obtained for MG is higher than conventional electricity rates, the greenhouse gas (GHG) emissions rate is reduced by 85%. In conclusion, the proposed d-TOU tariff scheme is suitable for the islanded MG system and it is beneficial for both the utility and the customer by not causing a financial burden to the utility and encouraging the customer to make a demand response in the future.
A Wheeled Mobile Robot Obstacles Avoidance for Navigation Control in a Static and Dynamic Environments
Authors: Sariff Nohaidda , Xing Bryan Tan Shun
Published: July 2023

This research focuses on the performance of the obstacle avoidance feature implemented on a wheeled mobile robot by using Sugeno Fuzzy Inference System (FIS). The test was done using a simulation software Webots and the layout was first draft out using walls, floors, and objects in order to set a boundary and obstacles for the simulation. To test the effectiveness and efficiency in terms of time and distance, the simulation time and trajectory of the Khepera implementing the Sugeno FIS was recorded and compared with the Khepera without implementing the Sugeno FIS. The inputs of the ultrasonic sensors were also recorded in order to analyze whether if the Khepera detects incoming objects or if Khepera follows the rules set in the algorithm.
Design and Control of Autonomous Rover for Foliage Navigation
Authors: Chow Kin Long , Phang Swee King
Published: July 2023

Implementation of UGV in civilian applications is getting trendy and normalized due to its solid achievement in executing mission under harsh environments. The UGV foliage environment-oriented applications even attracted the people’s attention in correspond sectors to ease their tasks with guaranteed performance. Given this, the development of the autonomous rover from sensors and control aspects with the consideration of foliage environment interest people to enhance its functionality. To ensure the sensor is not easily affected by the environment factor, the radar and the camera are selected to provide the environment perception to the rover. The approach for a linear Proportional-Derivative (PD) controller with the dynamic modelling of the UGV is also discussed in this paper. The study shows preliminary results that are working.
HAp-Ti-6Al-4V Interface Fretting Wear Failure Prediction in Different Bio-lubricants using FEM
Authors: Yi Teoh Zhi , Nagentrau M.
Published: July 2023

Plasma-sprayed hydroxyapatite (HAp) coated titanium alloy (Ti-6Al-4V) has been widely used as the material for artificial hip implants. However, studies have greatly challenged their long-time usage due to fretting wear behavior at the HAp-Ti-6Al-4V interface. Wear particles from the HAp coating may activate inflammation at surrounding organs, further leading to implant loosening, implant failures and even total hip replacement (THR) revision surgeries. Hence, present research aims to adopt the finite element methodology (FEM) in predicting fretting wear failure at the HAp-Ti-6Al-4V interface of uncemented hip implant femoral stem component under different body environments (bio-lubricants). A finite element (FE) model based on the half-cylinder on flat contact configuration subjected to actual mechanical and tribological properties under different bio-lubricants is developed with the modified Archard wear equation adopted to examine the fretting wear behavior through simulations. A parametric study is then conducted to evaluate the combined effects of different mechanical and tribological properties, including HAp coating thickness, bone elastic modulus and loading condition, under different bio-lubricants on the fretting wear behavior of HAp-Ti-6Al-4V interface. Lastly, single and multiple regression analyses are performed to formulate fretting wear predictive equation that acts as a fast-fretting wear failure prediction tool. The FE predicted results in this paper prove that the maximum wear depth at HAp-Ti-6Al-4V interface is promoted under lower coefficient of friction (COF), smaller HAp coating thickness, smaller bone elastic modulus and larger intensity of fatigue loading. The formulated predictive equations suggest a strong correlation between independent and dependent variables due to R-squared (R2) values being larger than 0.75 which guarantee goodness of fit.
The effects of different plant species in greenwall filtration system on lakewater treatment
Authors: Chan Nicole Yoong Xin , Tee Lee Hong , Oh Kai Siang , Lam Weng Hoong , Yoon Li Wan , Phang Eunice Siew Wei
Published: July 2023

It is a concern when 90% of Malaysia’s water supply comes from lakes that hold moderate to bad water quality status. Greenwalls are a sustainable modern-day filtration system that proves to be a solution in tackling this lakewater quality issue. To date, there are still questions unanswered regarding the treatment performance of the greenwall filtration system used for lakewater treatment as most research conducted is related to greywater treatment in terms of water quality. Thus, this research aims to investigate the effects of different plant species, filter media ratio and lakewater flowrate on the lakewater treatment performance in a greenwall filtration system. In this work. the plant species between Epipremnum aureum and Mentha piperita as well as the filter media ratio of coir to perlite between 3:1, 1:1 and 1:3, the lakewater flowrate between 15 L/h, 30 L/h and 160 L/h with the highest treatment efficiency for lakewater was investigated and chosen. First, experimental work was conducted with a constant plant species which was Epipremnum aureum and a constant filter media ratio of 1:1 (coir:perlite) to filter lakewater at different flowrates of 15 L/h, 30 L/h and 160 L/h where the initial and final sample of the lakewater was collected. The system ran for 3 hours each time and is referred to as a cycle. The COD and pH of the lakewater were tested before and after each cycle to compare the water quality. This study aims to justify and determine how different plant species as well as the filter media ratio and lakewater flowrate affect the lakewater treatment performance. The results show that Mentha piperita with fibrous root type, filter media ratio of 3:1 of coir to perlite and lakewater flowrate of 30 L/h provide the greatest removal efficiency of pollutants from lakewater. Ultimately, this study will contribute to the ever-growing research of greenwall filtration system for lakewater treatment making this treatment method more feasible for future commercial applications.
Study of refrigerant flow consistency and tolerance control of a distributor for air conditioner
Authors: Chew Eushayne , Al-Obaidi Abdulkareem Sh Mahdi , Chng Ming Hui
Published: July 2023

In the residential air-conditioning system, a refrigerant distributor is a device that connects the outlet of an expansion valve to each evaporator coil circuit when paired with a multi-circuit evaporator. The efficiency of the heat exchanger is significantly impacted by the two-phase refrigerant’s distribution. Only when the distributor has consistent performance can the heat exchanger be utilized efficiently. Hence, the aim of this study is to identify the impact of manufacturing tolerance of the distributor for air conditioner on the flow consistency. Preliminary analysis for different rules of factors such as the installation angle, barrel diameter and branching angle are studied through Computational Fluid Dynamics (CFD) simulation to analyze the parameter sensitivity. Based on the mean value of the standard deviation of the mass flow rate and quality at each path, the distributor’s performance is evaluated. It is found that the tolerance control on barrel diameter and installation angle will give significant impact on the flow performance, this is because the evaluation of standard deviation for mass flow rate and quality for these conditions are above average, that are 0.443 and 0.0161 respectively. On the contrary, a minimal influence is seen when the branching angle can be controlled within 1 degree tolerance. The following parameters’ effect on flow consistency are presented in order of largest to smallest: barrel diameter, installation angle and branch angle. A thorough study on the performance for the existing distributor is conducted and the tolerance of the important geometrical parameters (i.e., barrel diameter and branch angle) and working condition (i.e., installation angle) are identified.
Investigation of the Effect of the Wind Speed on the Aerodynamic and Architectural Design of Tall Buildings
Authors: Hui Yong Win , Al-Obaidi Abdulkareem Sh. Mahdi , Mari Tamil Salvi , Gunasagaran Sujatavani , Ching Michael
Published: July 2023

The magnitude, speed, direction, and distribution of the wind are known to have a negative impact on high-rise buildings, particularly when the building is extremely tall. As the height of the building increases, the effect of the wind increases significantly. This results in a high wind pressure exerted on the building which causes the wind loads subjected by the buildings to increase considerably. Thus, this study investigates the wind effect on tall buildings and proposes a solution to reduce the aerodynamic drag through a design that meets both architectural and aerodynamic considerations. Investigation of wind effect on tall buildings with different wind speeds, heights and shapes is carried out. Numerical methods are utilized to study the wind pressure, drag coefficient and pressure distribution on different types of buildings. ANSYS Fluent is used for computational fluid dynamics (CFD) simulation to assess the drag coefficient of the buildings. The drag coefficient of the building is determined in Reynold’s number range of 1×106 to 2×106. The study is conducted in low subsonic speed (Ma < 0.3). The result shows that the drag coefficient of the building tends to be constant at low subsonic speeds. Besides, the study found that the drag coefficient increases by 1% to 3% for every 0.1 m increment in the height of the building. The study also found that a cylindrical building has the lowest drag coefficient because of its more streamlined shape. Overall, this study provided guidance and recommendations for wind resistance which can be taken into consideration when designing tall buildings. Hence, the building can be built even taller while maintaining its rigidity and stability.
The effect of air velocity and indoor ambient properties on the effective operating range of an air ionizer device
Authors: Karim H , Nagentrau M , Ling K J N H , Chin W M
Published: July 2023

Air ionizers are devices that purify the indoor air by artificially generating negative air ions (NAIs) which are proven to improve air quality and well-being of humans. Hence, more ionizers are being incorporated into heating, ventilation and air conditioning (HVAC) applications nowadays. . Every ionizer has its effective range of operation, which is the area inside a room that can potentially be covered by significant concentration of NAIs compared to the general concentration of ions naturally present in the room. This range may change depending on the indoor temperature, humidity and fan speed of the HVAC unit as preferred by the room occupants. Present research intends to design an experimental setup that could measure negative air ion (NAI) concentration at varying distances from an ionizer under different values of the aforementioned parameters. The experiment was conducted inside an indoor psychrometric test room to allow controlling of ambient temperature and humidity. Air velocity through the ionizer was varied from 1.5 m/s to 4.5 m/s, whereas the range of temperature and relative humidity were set from 25°C to 31°C and 60% to 80% respectively. To evaluate the ionizer’s operating range, NAI concentration was measured at every preset longitudinal (0 cm to 75 cm), lateral (-25 cm to 25 cm) and elevation (-15 cm to 15 cm) distance relative to the ionizer for 6 minutes using an ion counter named “Air Ion Counter Model AIC2”. The results reveal that the ionizer’s effective operating range increased with velocity, with the furthest range recorded at 4.5 m/s. Whereas a negative correlation was found between the ionizer’s effective operating range with temperature and humidity, with the furthest range recorded at 25°C and 60% respectively. The results also show that most ions were distributed in areas below and towards the right side from the ionizer’s perspective.
Numerical Analysis of Delamination of High-Performance Concrete (HPC) Strengthened Reinforced Concrete (RC) Beam
Authors: Wong Jehoshaphat C.Q , Nagentrau M. , Mansor S.H.
Published: July 2023

This study investigates the numerical analysis of delamination behavior of high-performance concrete (HPC) strengthened reinforced concrete (RC) cantilever T-beam by using finite element method. A length of 1000 mm reinforced concrete cantilever T-beam and height of 1600 mm reinforced concrete column will be created. Besides that, the truss members such as the stirrups and the rebars will also be added into the structure as a reinforcement. The HPC layer will be assigned on the top of the cantilever T-beam as a coating material. The study is to investigate the influences on the delamination behavior when the thickness, width, and coefficient of friction of the HPC layer has been applied on the model as a coating material. Finite element model (FEM) will need to be created and justified in ABAQUS software before applying the parameters for analysis. Limited studies had been conducted on the delamination behavior of using HPC layer as a strengthening mechanism and analyze the output such as the COPEN and SDEG. Based on the results extracted from the software, the delamination behavior can be observed and analyzed and investigate the influence of difference parameter has been assigned. Therefore, this research paper will analyze the influence of the layer thickness, width of the layer, and the coefficient of friction between the substrate and the layer.
On the locating rainbow connection number of amalgamation of complete graphs
Authors: Bustan A W , Salman A N M , Putri P E
Published: July 2023

Locating rainbow connection number determines the minimum number of colors connecting any two vertices of a graph with a rainbow vertex path and also verifies that the given colors produce a different rainbow code for each vertex. Locating rainbow connection number of graphs is a new mathematical concept, especially in graph theory, which combines the concepts of the rainbow vertex coloring and the partition dimension. In this paper, we determine the locating rainbow connection number of amalgamation of complete graphs.
Coefficient estimation of simultaneous equations in the case of stochasticity of exogenous variables
Authors: Minitaeva A M
Published: July 2023

The paper deals with the question of obtaining such an estimate of the parameters of the model of simultaneous equations, which would have better statistical properties in comparison with the estimates of both the usual method of least squares and two-, three-step methods of least squares, as well as the method of fixed point and other methods of evaluating the coefficients of the equations considered in the system simultaneously. The main drawback of methods based on minimization of the sum of squares of deviations of real observations from some theoretical dependence is that the sum of squares of errors that correlate with the values of variables included in the expression for these errors is minimized. A violation of the basic assumption of least-squares methods about the independence of predetermined variables and errors leads to the fact that least-squares estimation methods in this case lose their best properties: unbiasedness, efficiency, and consistency. The paper proves the theorem about the efficiency of estimates obtained using two-step least squares methods and that of estimates obtained using the method of factorization of simultaneous equations.
Critical temperature in 2D square Ising model with anisotropic coupling constant using Kramers-Wannier duality
Authors: Aviles L A , Gammag R P
Published: July 2023

To solve the 2D square Ising model incorporating anisotropy, we discuss a graphical representation of Kramers-Wannier duality. The method yields an equation relating the critical temperature (Tc
) to the horizontal and vertical coupling constants. The result reproduces the known exact solution by Onsager. The equation derived was utilized to plot Tc
as a function of anisotropy by introducing the ratio (α) of the coupling constants. A phase diagram is then obtained showing Tc
as an increasing function of α In the limit as α approaches zero, the critical temperature asymptotically goes to zero. This agrees with the exact solution of the 1D model.
Analytical solutions to the isothermal Euler equations with time-dependent damping
Authors: Jia Xinyue
Published: July 2023

In this paper, we construct a class of analytical solutions to the one dimensional compressible isothermal Euler equations with time-dependent damping. By introducing a special density function ρ(x, t) = e

c(t)x+d(t), we obtain a family of analytical solutions. A sufficient condition for the solution to blow up in finite time is given. On the basis of the conclusion, the analytical solutions to the initial boundary value problem of the pressureless Euler equations are obtained.
Using multi-flexible body dynamic analysis and the Taguchi method to decrease the variation of output angular velocity in a double circular-arc harmonic gear drive
Authors: Ruan J C , Lee C K , Wang C Y , Tsai Y C , Sung H H
Published: July 2023

The performance of a double circular-arc tooth harmonic gear drive, which offers advantages over traditional designs, such as lower stress during contact and increased fatigue life, was investigated in this research. The gear drive’s meshing was simulated using dynamic analysis software RecurDyn, and a significant variation in output angular velocity was observed. To address this issue, experiments were planned using the Taguchi method with the L9(34) orthogonal table. The data was analyzed using techniques such as average value calculation, signal-to-noise ratio calculation, variance analysis, and response chart analysis to identify the control factors with the greatest impact on output angular velocity variation. It was found that an improved design with lower output angular velocity variation could be obtained by adjusting these control factors to optimal levels. The findings suggest that the transmission quality of double circular-arc harmonic gear drives can be enhanced by combining multi-flexible body dynamic analysis with the Taguchi method.
FDT for fluctuations of a special perturbated harmonic oscillator and its application in q-deformed Harmonic Oscillator
Authors: Yin Huangcheng
Published: July 2023

In this paper, we will use fluctuation dissipation theorem on the harmonic oscillator with time correlation creation annihilation operator as the perturbated term and through calculation, we find that the exact value of the dissipation associated Imχ of this special perturbation harmonic oscillator is exactly equal to π. Next, we give its potential application in the q-deformed harmonic oscillator, which means connect the q-deformed harmonic oscillator with fluctuation dissipation.
Algorithm Research and Accuracy Influence Factor Analysis of Calibrating Antenna Pointing of Sounding Radar by Solar Method
Authors: Yin Lian , Ye Fei
Published: July 2023

The calculation of the reception ability of the L-band radiosonde radar to the solar minimum energy flux density proves that it can be used for antenna pointing calibration by the solar method. The test found that the elevation deviation of the solar method comparison observation software is within 0.3° and the azimuth deviation is within 0.5°, and the accuracy meets the deviation index requirements of the L-band sounding radar antenna pointing. By analyzing the influence of radar frequency, antenna control system angle and radar gain on the solar method test, it is found that the solar method test is the most accurate when the frequency is around 1676MHz and the antenna control system and gain are set as “automatic” as far as possible. In addition, the solar calibration method is easy to operate, can be widely applied, can effectively check the radar operation status, and timely detect radar faults.
Initial Rotor Position Detection of SPMSM with High-frequency Signal Injection
Authors: Liu TingZheng , Gu DaWei , Cai FuMen , Mou XiaoNing , Tian JiangXianFeng
Published: July 2023

The accuracy of initial rotor position detection is important for senseless control, meanwhile, high frequency signal injection takes its advantages for its simple principle, small calculation amount and good real-time performance. In this paper, the principle of high frequency signal injection is analysed and systematically studied from position information error reading and the direction of d-axis. Besides, factors which may lead to the error of position information error reading is also studied, the second-order notch filter is added to get higher accuracy. Finally, the model of high frequency signal injection is set up to verify the effectiveness of the method, the result shows that method can run well at 0 speed and effectively estimate the actual rotor position.