bluuebunny/crossref_metadata_2025 huggingface dataset:
NMR measurement of small-molecule diffusion in PVA hydrogels
Authors: Regan David G. , Momot Konstantin I. , Martens Penny J. , Kuchel Philip W. , Poole-Warren Laura
Published: July 2024

Hydrogels are biocompatible polymeric materials that are becoming increasingly important in biomedical applications, such as drug delivery and tissue engineering. Understanding of small-molecule diffusion in these systems is important in the contexts of controlled drug release; transport of nutrients (e.g., O2 and growth factors) into the gel; and transport of cellular waste out of the gel. In this work, the diffusion coefficient of the aromatic amino acid phenylalanine (Phe) in non-crosslinked and crosslinked poly(vinyl alcohol)(PVA)hydrogels was measured using two NMR diffusion methods, CONVEX and the standard pulsed-gradient spin-echo (PGSE). Pulsed field-gradient (PFG) NMR measurements provide the advantage of measuring the molecular selfdiffusion coefficient directly and without having to rely on the physical release of the solute, but are often difficult to perform in tissues and hydrated polymers due to a large water signal. CONVEX is a recently proposed diffusion method that alleviates this problem by means of NMR excitation-sculpting water suppression. In the measurements presented here, CONVEX results were superior to those from PGSE measurements with respect to every test applied, and enabled a reliable comparison of the diffusion coefficients of Phe in crosslinked and non-crosslinked hydrogels. The value of D(Phe) was smaller in the non-crosslinked hydrogel than in the crosslinked gel; this finding is discussed in the paper.
Anomalies of the fickian diffusion during 2D-decomposition of superconducting YBa 2 Cu 3 O 6+X /Y 2 BaCuO 5 composites
Authors: Nechaev Yury S.
Published: July 2024

Based on a thermodynamic analysis of the relevant experimental data, some anomalies of the diffusion mass-transport during two dimensional (2D) decompositioning high-temperature superconducting (HTSC) cuprates are considered. Possible mechanism for the manifestation of phase fluctuation-like effects in the HTSC cuprates, especially with respect to the physical properties of melt-textured composites, thin films, coatings, nanomaterials and heterostructures are discussed.
Diffusion of urea through membranes
Authors: Günther Ulrike , Hartmann Marcus , Wartewig Siegfried , Neubert Reinhard
Published: July 2024

Non-invasive real time monitoring of topical drug delivery is an important subject of dermatopharmaceutical research. It has been proved that Fourier transform infrared attenuated total refection (FTIR-ATR) is a versatile technique to study drug diffusion through artificial membranes and biological systems. Urea is widely used as moisturizer or ceratolyticum in pharmaceuticals, therefore, its diffusion behaviour in biological membranes is of great interest.
Application of Boltzmann’s integration method under non-ideal conditions
Authors: Heinke Lars
Published: July 2024

Boltzmann’s integration method may prove to be a very powerful tool to study the transport diffusion of guest molecules in nanoporous host systems. In many cases, however, the prerequisites for applying this method are not completely fulfilled. In the following, the consequences of these deviations on the accuracy of the obtained results are discussed. It is found that the results of Boltzmann’s integration method can be corrected by different considerations. The discussion is focussed on the concentration profiles observed during the adsorption and desorption of methanol in ferrierite-type crystals as observable by interference microscopy.
Cube-based diffusion algorithm
Authors: Zschiegner Stephan , Russ Stefanie , Bunde Armin , Kärger Jörg
Published: July 2024

We study molecular diffusion in (linear) nanopores with different types of roughness in the so-called Knudsen regime. Knudsen diffusion represents the limiting case of molecular diffusion in pores, where mutual encounters of the molecules within the free pore space may be neglected and the time of flight between subsequent collisions with the pore walls significantly exceeds the interaction time between the pore walls and the molecules. In this paper we present in full detail the algorithm, which we used in our previous studies, where we showed complete equivalence of self- (or tracer-) and transport diffusion.
Absolute pore size distributions from NMR
Authors: Sørland Geir Humborstad , Djurhuus Ketil , Widerøe Hege C. , Lien Jan R. , Skauge Arne
Published: July 2024

NMR measurements on core samples saturated with brine returns valuable information on the porous structure of the rock core. Monitoring a single fluid component in a relaxation experiment reflects the pore size distribution and thus the degree of sorting of the porous rock. The basic assumptions are that the mobility of the component confined in the porous rock is of such a value that a small fraction of the probing molecules experience the surfaces of the pores and that the surface relaxation strength is fairly independent of pore size. Then one may combine diffusion measurements at short observation times returning a value for the average surface to volume ratio with ordinary relaxation time measurements to obtain an absolute pore size distribution instead of the standard T2 distributions or T1-T2 correlated two dimensional distributions.
Adsorption and desorption kinetics for diffusion controlled
systems with a strongly concentration dependent diffusivity
Authors: Ruthven Douglas M.
Published: July 2024

The formal solution to the diffusion equation for transient adsorption in a semiinfinite medium with a strongly concentration dependent diffusivity, originally derived by Fujita ( 3 ), has been extended to desorption. Profiles for adsorption and desorption are compared and simplified asymptotic expressions which are useful when the diffusivity ratio is large are derived. The effect of a strongly concentration dependent diffusivity on adsorption and desorption kinetics is briefly considered.
Polymer dynamics from synthetic to biological macromolecules
Authors: Richter Dieter , Biehl Ralf , Monkenbusch Michael , Hoffmann Bernd , Merkel Rudolf
Published: July 2024

In soft materials entropic and enthalpic contributions are of similar magnitude and balance each other. Therefore, the macroscopic mechanical and rheological properties and the phase changes are determined to a high degree by thermal motion of the atoms and molecules. Most of the relevant dynamics takes place on mesoscopic length and time scales in between the picosecond atomic scale and the macroscopic frame. Allowing for the proper space time observation window, neutron spin echo (NSE) spectroscopy uniquely allows to address these motions. Here we briefly present some key experimental results on the mesoscopic dynamics of polymer systems, starting from the standard model of polymer motion - the Rouse model. We briefly touch the role of topological confinement as expressed in the reptation model and discuss in some more detail processes limiting the confinement. In the second part we touch on some new developments relating to large scale internal dynamics of proteins by neutron spin echo. We will report results of some pioneering studies which show the feasibility of such experiments on large scale protein motion which will most likely initiate further studies
Electro-diffusion at different length scales
Authors: Grysakowski Bartosz , Lewenstam Andrzej , Danielewski Marek
Published: July 2024

The modelling of electro-diffusion in the multicomponent system in open space and time domains has been only recently addressed and made numerous applications in biology, fuel cells, electrochemical sensors and reference electrodes possible. In this work we show the numerical simulations of electrical potential over time and resulting electrochemical impedance spectra of ion-selective membrane electrodes (ISE’s). The numerical results are obtained by use of the coupled Nernst-Planck, Poisson and continuity equations (forming the NPP model). The equations are solved by means of the finite difference method, the Rosenbrock solver with the use of Matlab (by MathWorks) platform. The potential-time response of the ISEs in open- and closed-circuit conditions as a function of varying heterogeneous rate constants, ionic concentrations and membrane thickness are computed. The potential-time response to small-current perturbation is applied for simulations of the impedance spectra. The results obtained show that the membrane with Nernstian response presents only one capacitive arc in the impedance spectra, related to conductivity and dielectric properties of the membrane material. Non-Nernstian behaviour is related to slow ionic transport through the membrane|solution interfaces and is manifested by the appearance of an additional (capacitive) arc between the highfrequency bulk and the low-frequency (Warburg) arcs. The presented approach directly relates the diffusivities in the membrane and the interface properties (heterogeneous rate constants determining the transport across interfaces) to the characteristic properties of the impedance spectra (characteristic radial frequencies). It is concluded that the Matlab platform allows solving the NPP problem and simulating the non-linear effects in electrodiffusion in a convenient way.
Structural properties of zirconia doped with some oxides
Authors: Abbas Hussien Ahmed , Hamad Fadwaa Fwad , Mohamad Atrees Khair , Hanafi Zeinab Mohamad , Kilo Martin
Published: July 2024

Zirconia powders doped with different amounts of dopants (CeO2, Gd2O3, and CaO) were synthesized by a citrate technique. X-ray diffraction for samples sintered at 1500 °C revealed that the zirconia ceramics were stabilized in the cubic phase above 12 mole % CaO and 10 mole % Gd2O3, while tetragonal zirconia is obtained above 15 mole % CeO2. Relative densities up to 99.5% were obtained. The effect of dopant concentration on the lattice parameter, average crystallite size, microstrain was studied. The cubic lattice parameter increases nearly linearly with increasing the concentration in case of CaO and Gd2O3. The tetragonal lattice parameters at and ct increase nearly linearly with increasing the concentration of CeO2. The average crystallite size was found to be larger than 600 nm for the samples investigated.
Developing STEAM educators’ proficiency scoring framework
Authors: Palisoc Caesar , Marie Paz Morales , Avilla Ruel , Ayuste Thaddeus Owen , Ramos-Butron Benilda , Casilla Nica
Published: July 2024

The study aimed to develop the scoring framework for the selfrating proficiency indicators for Philippine STEAM educators. The study further sought to design mathematical framework and program for scoring STEAM educators’ proficiency and validate the designed scoring program. About 1507 responses from the self-rating STEAM proficiency tool were used to undergo the three tier quantitative and qualitative validation. Mathematical equations were derived to direct the development of the scoring programs using Microsoft Excel and Fortran. Results show an agreement between the proficiency profiles generated from the Microsoft Excel and Fortran program. Using the online survey and the classroom observation rating, proficiencies were compared as determined through the Fortran program of the predetermined career stage (distinguished, highly proficient, proficient, beginner). Lastly, qualitative validation was performed by comparing the generated codes in the interview transcripts and observation notes and the attributes in the PPST domains and TPACK dimensions. Qualitative validation indicates that the occurrences of the indicators in the interview and classroom observation matched with the expected attributes per career stage as per the PPST. This indicates that the validation of the scoring system developed for the online survey generate the STEAM educator proficiency. Further, the scope of the scoring framework developed is universal and may be adapted to suit any local setting. However, increasing the number of interviews and classroom observations to 10% of the sample population of teachers will produce a robust scoring program.
Simulation Analysis of Asymptotic Normality of Maximum Likelihood Estimation Based on the Fisher Scoring Algorithm in Generalized Poisson Regression Modeling
Authors: Abusini Sobri , Dinnullah Riski
Published: July 2024

Maximum Likelihood Estimation (MLE) is a method widely used in statistics to estimate the parameters of statistical models. One of the critical aspects of MLE is its asymptotic properties, especially its asymptotic normality. Asymptotic normality refers to the property where the MLE distribution approaches a normal distribution as the sample size tends to infinity. Meanwhile, Fisher Scoring Algorithm (FSA) stands out as a versatile and efficient tool for parameter estimation in various models and statistical disciplines. This research was conducted to obtain the distribution of the MLE estimator based on the FSA. The simulation study used the Bootstrap Method in the Generalized Poisson Regression Model with 600, 700, 800, 900, and 1000 repetitions. The simulation results show that the MLE estimator based on the FSA has the same distribution as the classical MLE estimator; namely, a Normal distribution.
Masyarakat madani (civil society) dalam perspektif Buddhisme
Authors: Pratiwi Pratna Dian , Nata Pramudita Mei , Bramantio Krisdiantoro Alfani , Sutadi Sutadi
Published: July 2024

Di Indonesia membutuhkan tumbuh dan berkembangnya masyarakat madani (civil society), akan tetapi hingga saat ini pembentukan masyarakat madani di Indonesia masih kurang optimal. Berkenaan dengan hal tersebut dalam ajarannya Buddha mengajarkan mengenai hiri dan ottapa sebagai landasan diri dalam menumbuhkan karakteristik sadar hukum, oleh karena itu peneliti merasa tertarik dengan hal tersebut sehingga peneliti ingin melakukan kajian mengenai masyarakat madani (civil society) dalam perspektif Buddhisme. Untuk melakukan kajian ini peneliti menggunakan metode library research atau kajian kepustakaan yaitu dengan mengumpulkan data pustaka, membaca dan mencatat serta mengolah bahan penelitian, dengan demikian peneliti akan mengkaji Tipitaka secara mendalam yang berkaitan dengan masyarakat madani (civil society) melalui sumber primer dari Tipitaka pali dan sekunder yang berasal dari pendapat maupun pembahasan penulis lain.Â  Hasil dari penelitian ini yaitu dalam pembentukan masyarakat madani (civil society) dalam persepektif Buddhisme membutuhkan pemenuhan terhadap kriteria merujuk pada 7 (tujuh) prinsip suku Vajji, hiri, dan ottapa yang ditunjang dengan pemenuhan prasyarat dalam membentuk masyarakat yang madani.Â  Dengan demikian, dapat disimpulkan bahwa masyarakat yang madani dalam persepektif Buddhisme adalah masyarakat beradab yang mumpuni dalam perkembangan ilmu pengetahuan, merealisasi hiri dan ottapa, serta memenuhi syarat-syarat pembentukan masyarakat yang madani (civil society).
Memahami Self-Efficacy Melalui Prespktif Saddha Dalam Agama Buddha
Authors: Dewi Kuhana , Kabri Kabri
Published: July 2024

Agama Buddha telah memberikan kontribusi yang luar biasa terhadap pemahaman manusia tentang psikologi dan pemahaman diri. Self-efficacy merujuk pada keyakinan individu terhadap kemampuan mereka untuk mencapai tujuan, mengatasi hambatan, dan menghadapi tantangan dalam hidup. Dalam Agama Buddha, konsep ini mendapatkan perspektif menarik dalam bentuk "Saddha," yang merupakan keyakinan mendalam terhadap ajaran Buddha, Dhamma, dan Sangha. Penelitian ini bertujuan untuk mengeksplorasi bagaimana konsep Saddha dalam Agama Buddha dapat berkontribusi pada pemahaman self-efficacy individu. Penelitian ini menggabungkan pendekatan interdisipliner yang mengintegrasikan psikologi, agama, dan filosofi untuk memberikan wawasan lebih mendalam tentang bagaimana self-efficacy dapat diperkuat melalui perspektif Saddha dalam Agama Buddha. Metode penelitian yang digunakan adalah studi kepustakaan dengan sumber data dari literatur ilmiah yang relevan. Teknik pengumpulan data melibatkan pencarian dan analisis isi. Hasil penelitian ini dapat membantu individu dalam mengatasi ketidakpastian, rasa takut, dan ketidakmampuan, yang seringkali menjadi hambatan dalam mencapai tujuan dan meraih kebahagiaan. Dengan memahami konsep ini, individu dapat mengembangkan alat-alat yang lebih efektif untuk memotivasi diri sendiri, meraih tujuan, dan menghadapi tantangan hidup dengan percaya diri dan keyakinan yang mendalam.
Crónica de una extinción anunciada: el caso del ajolote Abystoma velasci en Sierra Gorda de Guanajuato
Authors: Leyte-Manrique Adrian , Alejo-Iturvide Francisco
Published: July 2024

Amphibians are organisms that are very sensitive to changes in their environment, which has an impact on their survival, such is the case of emblematic animals such as ambistomatids, a family of amphibians whose larval forms are commonly known as axolotls, of which 18 species are known in Mexico and where one of them is the Bajío axolotl Ambystoma velasci. In this paper I make a chronicle and a reflection on the natural history of a population immersed in Charco Azul, Xichú, Guanajuato, within the Sierra Gorda-Guanajuato Biosphere Reserve, where I mention the real problems of the species to be able to survive in the face of abrupt changes in its environment, and that in the future may lead to the loss of a part of the herpetofaunal wealth of Guanajuato.
Automated Farming System Using Distributed Controller: A Feasibility Study
Authors: Rashid Mohammad Mahbubur , Sall Alioune , Hasan Tahsin F
Published: July 2024

Abstract— Agriculture is fundamental to a human being because it has itranted humanity's evolution. It is among the essential activities that ensure the development of the human being. So, it is capital to ensure good work and the efficiency of agricultural production. Thus, the research is focused on the domain of agriculture automation to increase the agriculture production yield with less water consumption and less risk in Africa, particularly in Senegal, where agriculture delays reaching food self-sufficiency because of rudimentary materials. The farmers are using a hilar, plough, and hoe for doing their daily tasks. The watering can still be used to water a large area of crops and is done randomly. The chemical pesticide is done manually using a manual sprayer, which causes enormous risks of diseases to the farmers and destroys the field and even the crops. This thesis describes an approach to automated farming by the use of a Sprayer Robot based on Arduino. Besides the Sprayer Robot, the paper also presents an automated irrigation system based on the Senegalese climatic parameters and soil textures through CROPWAT and CLIMWAT. The automatic irrigation system is done with a programmable logic controller, the master controller of the overall design, including the Sprayer Robot. Moreover, a SCADA graphical interface is also implemented for the monitoring of the whole system. The project, tested in simulation with the CROPWAT and CLIMWAT data, could give no reduction yield if applied and also reduced risk of diseases due to chemicals.
Development of Agile Project Management Framework in Oil and Gas Companies in Kuwait
Authors: Aliasser Abdullah , Adesta Erry Y. T.
Published: July 2024

The Petroleum industry requires construction and renovation of 'upstream' and 'downstream' facilities. Kuwait Oil Company is dealing with the exploration and manufacturing of crude oil & natural gas. EPC projects perform an essential role in the technology of new physical amenities to keep or decorate production. Project administration has developed incredibly over time due to several strategies to deal with building activities. Schedule and Budget are the two most important concerns required to be optimised all through execution. Therefore, a very excellent & efficient challenge management system is wished and has to be framed to deal with the fundamental capital construction projects. In effect, help the organisation makes have an impact on the country's economy.
Analysis of Blockchain-Based Ripple and Swift
Authors: Islam Md Rafiqul , Rashid Muhammad Mahbubur , Mohammed Ataur Rahman  , Muslin Har Sani Bin Mohamad  , Abd Halim Bin Embang
Published: July 2024

Blockchain is one of the modern new edge technologies which is capable of transforming the traditional financial system, especially in the financial industry. Cross-border money transfer is one of the big challenges in terms of security, cost, and other regulatory issues. Presently, the most popular international money transfer system is SWIFT in the financial sector. Ripple is one of the upcoming payment networks for cross-border payment systems based on blockchain technology and uses its own cryptocurrency called XRP. This paper highlights the implementation challenges of SWIFT and Ripple networks. It also underlines the features of whether the blockchain-based application can transform the existing traditional payment system and how the new proposed system works. This paper is also explained how the proposed system has some advantages over the traditional system. Still, SWIFT is the market leader in remitting money for cross-border payments. On the other hand, the Ripple network is an emerging technology that may contribute a lot to cross-border payment in the financial industry in the near future.
Characteristic Study for Wireless Charging System
Authors: Motakabber S. M. A. , Alam AHM Zahirul , Binti Jamal Nur Fadillah , Khan Mazbahur Rahman
Published: July 2024

Power is an essential requirement in these modern lifestyles. Electronic gadgets like cell phones, laptops, etc., need the least power to charge. The utilization of Wireless Power Transmission (WPT) has been a hot issue among researchers these days. Nowadays, the application of wiring is becoming very inconvenient since everything cannot be used as there are some limitations and dangers. Therefore, several techniques have been found to carry out the wireless charging purpose in this study. The power transmission through the air is much easier to implement, more efficiently and persistently charged without the demand of connection physically. In this paper, a comparison between the three techniques for wireless power chargers has been determined. Among these three, it is found that the utilization of inductive coupling techniques is the best way to implement the system.
Multivariate EEG Signal Processing Techniques for the Aid of Severely Disabled People
Authors: Ibrahimy Muhammad I. , Ibrahimy Ahmad I.
Published: July 2024

Electroencephalography (EEG) has been used for several years as a trace of signals for facilitating subjects with serious infirmities to communicate with computers and other devices. Many studies have revealed the correlation of mental tasks with the EEG signals for actual or fictional movements. However, the performance of Brain Computer Interface (BCI) using EEG signal is still below enough to assist any disabled people. One reason could be that the researchers in this field (motor imagery based BCI) normally use two to three channels of EEG signal. This might limit the performance of BCI, as an extra source of information generally helps in detecting a person's motor movement intentions. Therefore, the proposed research work is involved with three or more channels of EEG signal for online BCI. Two fundamental objectives for BCI based on motor movement imagery from multichannel signals are aimed at in this research work: i) to develop a technique of multivariate feature extraction for motor imagery related to multichannel EEG signals; and ii) to develop an appropriate machine learning based feature classification algorithm for Brain Computer Interface. Nevertheless, all other problems like interfacing and real-time operations with current BCIs are also addressed and attempts are made to reduce the problems. The methodology can be described by following steps as follows: i) at least 3 channels of EEG signal are recorded; ii) a few features are extracted from preprocessed EEG signal; iii) all extracted features are classified to generate commands for BCI; iv) finally evaluate the performance of the proposed algorithm for BCI. The challenge of this research work is to investigate and find an appropriate model for online (real-time) BCI with a realistic performance to be made in achieving better lives for people with severe disabilities in Malaysia and abroad.
A New Topology of High-Efficiency DC-DC Hybrid Boost SEPIC Converter for PV Cell
Authors: Akter Khadiza , Motakabber S. M. A. , Alam AHM Zahirul , Yusoff Siti Hajar
Published: July 2024

This paper initiates a high-gain high efficiency step-up DC-DC converter based on Boost SEPIC (Single Ended Primary Inductor Converter) hybrid topology for photovoltaic application. Customarily DC-DC converter circuit is a widely used technique to improve the voltage level of solar cells. However, for low output voltage and low efficiency, they are not sufficient enough to provide expected outcomes. To defeat the conventional system a hybrid Boost SEPIC topology has been recommended with enhanced performance. The proposed design of the DC-DC converter circuit can provide a high voltage gain without decaying its overall performance. The modified converter topology is being worked by a single switch with low switching voltage stress over the semiconductor devices. The main edge of the proposed design is that it can perform efficiently without using any transformer, the combined design of Boost SEPIC topology increases the voltage gain much higher compared to the conventional Boost or SEPIC. The maximum Power Point Tracking (MPPT) algorithm is used to obtain maximum power from a photovoltaic source. MATLAB Simulink and PSIM software has analyzed the performance of the newly designed converter circuit thoroughly.
Performance Analysis of a Hybrid Free Space Optics/ Visible Light Communication Systems
Authors: Ab Aziz Siti Hajar , Mohd Nor Norhanis Aida Binti , Zainal Abidin Mohd Shahnan Bin
Published: July 2024

A hybrid free space optical (FSO)/visible light communication (VLC) system is a remarkable wireless technology for overcoming the last mile gap and for future broadband wireless communication. In detail, this research examines the hybrid FSO/VLC system performance using Optisystem 19 software. The system performance of the wireless hybrid FSO/VLC is evaluated using the bit error rate, quality factor, and eye diagram for weak and strong turbulence regimes referring to the Gamma-Gamma atmospheric turbulence channel. At BER of  the maximum attainable distances are 1.3 km and 1.8 km for 0 dBm and 5 dBm transmitted power in clear weather, respectively. However, when the transmit power reduces to -5 dBm, the measured BER drops to 8×10-3 with a distance of 1 km link range. Moreover, when the power increases from 0 dBm to 5 dBm, the distance of the connection between Tx and Rx can be extended from 1.1 km and 1.9 km under weak turbulence conditions at the target BER of 10-9. In contrast, at the same target of BER, only 5 dBm of transmitted power managed to capture the signal at a distance of 1.7 km for strong turbulence conditions. This result can be the benchmark research to investigate and identify the best strategies for validating future experimentation difficulties.
Performance Analysis of a Newly Designed DC to DC Buck-Boost Converter
Authors: Uddin Mohammad Iftekher , Kazi Samira Shamsi Huq  , S M Salam
Published: July 2024

Most of the electronic devices operate on the principle of the voltage-controlled voltage source. With the improved technology and an increase in circuit complexity, the necessity of controlling the output voltage level irrespective of the change in the load current or line voltage is increasing at a tremendous rate. Moreover, battery dominated electronic devices and gadgets demand a wide range of variation and control over DC voltage and power, which currently faces many challenges. This study proposes a design of a DC to DC Buck-Boost converter and analyzes the converter's performance by placing the Pulse Width Modulation of 40% and 48% duty cycles for buck-mode and 66% and 100% for boost-mode in the switching circuit. The result is simulated in the Proteus Suite software.
Direct Torque Control of Three Phase Induction Motors Concept and Principles
Authors: Ali Ayman M. , Badr M. Abdel Latif , Hosain Farid S.
Published: July 2024

This paper thoroughly illustrates the Direct Torque Control (DTC) concept, principles and theory. It describes the dynamic behavior of a direct torque controlled three-phase induction motor. The complete analysis begins with a suitable mathematical model of the motor and the inverter circuit. It represents the DTC main parts and describes its operation. This paper also illustrates how the DTC can become a base for speed control schemes and the ability to switch between torque & speed control.
Noise Reduction Techniques in ECG Signal
Authors: Muhumed Sakarie M. , Ibrahimy Muhammad I.
Published: July 2024

The problem of noise interference in ECG signals has been addressed in this paper. Specifically, a method has been developed to filter out Electromyography noise (EMG) from ECG signals. A dataset of ECG signals with varying levels of EMG noise has been collected using the MIT-BIH dataset. An algorithm has been designed and implemented using the DA FIR filter coupled with Kaiser windowing technique to filter out the noise. The algorithm has been tested on the collected dataset using MATLAB. The performance of the algorithm has been evaluated by calculating the Signal-to-Noise Ratio (SNR) and the Mean Squared Error (MSE). The effectiveness of the algorithm in reducing the EMG noise in the ECG signals has been demonstrated by the results. The algorithm's limitations and future work were discussed in this paper. Interesting future works could include using other filtering techniques to enhance the performance or deep learning techniques to improve noise cancellation. Overall, the effectiveness of using signal processing techniques to filter out EMG noise from ECG signals has been demonstrated and resulted in clearer and more accurate signals for diagnostic purposes.
Effect of Inductor for Designing an Inverter to Maximize Solar Panel Power Output
Authors: Hasan Muhammad Wasif , Alam AHM Zahirul
Published: July 2024

The current methods to maximize solar cell efficiency have proven too complex for low-power solar applications. In addition, traditional methods, such as changing the orientation of a solar panel, can be too difficult for large photovoltaic arrays. Therefore, in this work, various analyses will be done with the critical components of a solar PV circuit to estimate its maximum power point (MPP). The effect of inductance for designing a solar cell system for maximized power by controlling the  DC/DC Boost controller.
Tech Stocks and Dividend Policy in Malaysia
Authors: Ibrahimy Ahmad Ibn , Amjad Saad Bin
Published: July 2024

Malaysia is a developing country, and the capital market is evolving here more than in other emerging markets. Literature on dividend policy has generated extensive theoretical and empirical research, but no broad consensus has emerged after decades of research. The sole determination of this study is to determine the factors affecting the dividend policy of technology stocks listed in Bursa Malaysia. The paper attempts to present the primary studies on dividend policy to provide a thorough understanding of technology corporations’ payout practices in Malaysia and reaches inconclusive evidence.
Performance Prediction of D.C. Motor Fed From Half-Controlled Bridge Rectifier
Authors: Nasir Bilal
Published: July 2024

Controlled rectification is the process of obtaining a controlled output DC voltage from a constant AC voltage. This can be used in the speed control of the DC motor to provide rapid torque control and a quick starting response. In this work, a three-phase half-controlled bridge rectifier has been used. The average output DC voltage varies smoothly by varying the firing angle (α). Different methods of analysis such as state-space and Fourier-series, are used to obtain the performance of the DC motor fed from the bridge-rectifier supply. However, these methods do not deal with the prediction of the discontinuous conduction phenomenon which occurs during the operation of the DC motor with a variation of delay angle. This paper deals with the prediction of performance characteristics during the operation of the DC motor fed by a 3-phase half-controlled bridge rectifier, including the transient as well as steady-state operation with a variation of delay angle as well as application of load torque at starting.
Performance Analysis of Different Grid Substations with Demand-Side-Management-Based Optimal Power Usage
Authors: Uddin Farhad , Tripura Dilip Kumar , Salam Syed Munimus , Rashid Muhammad Mahbubur
Published: July 2024

This study is centered on analyzing the performance of two power grid stations in the southern grid zone of Bangladesh. Additionally, it encompasses the effect of a demand-side management simulation of grid line operation. Firstly, this paper briefly discusses the grid circle's interconnected grid system and the serving districts' generation capacity.  An analysis of schematic diagrams and an examination of the current substations and transmission cables in place has been conducted. The maximum load research has been addressed at several significant grid sub-stations, examining the capacity of a specific grid zone and determining the necessity for expanding the corresponding grid infrastructure. This study presents a comprehensive analysis of the DSM employed in the grid substation, as well as an examination of the various possibilities of renewable energy installations within it. Additionally, this study encompasses the investigation of power transmission and the accompanying structures employed for transmission, as well as the analysis of the estimation technique and any other interconnected domains.
MATLAB-Based Vibration Signal Processing for Fault Diagnosis
Authors: Motakabber S. M. A. , Mohammad Mominul Hoque  , Md. Rafiqul Islam  , Sany Ihsan  , Gazi Zahirul Islam  , AHM Zahirul Alam
Published: July 2024

Traditionally, vibration signal processing has been performed using analog and digital signal analyzers or writing code in intermediate and high-level computer languages. However, the advent of higher-level interpretive-based signal processing software products such as MATLAB has added a new dimension to vibration signal processing. This paper presents a method for analyzing motor vibration data using MATLAB. The method first pre-processes the vibration data to remove noise and baseline wander. Then, the frequency spectrum of the vibration signal is calculated using the Fourier transform. The frequency spectrum is then used to identify the dominant frequencies in the vibration signal. These dominant frequencies can be used to identify potential problems with the motor, such as bearing defects or misalignment. The method was studied on a set of vibration data collected from open source online data of a real motor. The results showed that the method was able to identify the dominant frequencies in the vibration signal accurately. The method was also able to identify the potential problems with the motor. This paper demonstrates the effectiveness of using MATLAB for analyzing motor vibration data. The method presented in this paper can be used to improve the reliability and efficiency of motor maintenance.
Ansvarshierarki i lægemiddelomsorgen på plejehjem
Authors: Frantzen Sara Elgaard , Dam Mie Seest , Gjødsbøl Iben Mundbjerg
Published: July 2024

Polyfarmaci—indtagelse af flere lægemidler samtidig—er et velkendt fænomen blandt ældre, som hovedsageligt er blevet undersøgt kvantitativt med henblik på at definere, hvor mange lægemidler der er for mange. I denne artikel ser vi ud over de numeriske definitioner af polyfarmaci for i stedet at udforske de konkrete praksisser, som lægemidlerne indgår i. Gennem etnografisk feltarbejde på to danske plejehjem undersøger vi, hvordan lægemidler får aktiv indflydelse på plejehjemsbeboeres hverdag og på den omsorg, som plejepersonalet yder. Inspireret af Science and Technology Studies (STS) analyserer vi, hvordan polyfarmaci udspiller sig og erfares i praksis ved at betragte lægemidler som en omsorgsteknologi. I det daglige arbejde med at administrere lægemidler sikrer retningslinjer for ’rationel farmakoterapi’, at den rigtige patient får den rigtige medicin til den rigtige tid. Vores empiriske fund viser imidlertid også, at arbejdet med sikker lægemiddelhåndtering begrænser plejepersonalets muligheder for at inddrage beboerne i deres egen behandling. Vi viser, hvordan det nødvendige fokus på korrekt og sikker lægemiddelhåndtering samtidig skaber et fragmenteret ansvarshierarki blandt plejepersonalet, som hverken inviterer til dialog mellem plejer og beboer eller mellem fagprofessionerne. Det betyder, at uautoriseret og ufaglært personale, som er tættest på beboerne, når lægemidler gives, står uden beføjelser til at handle selvstændigt og ikke involveres på tværs af autoriserede fagligheder. Vi konkluderer, at ansvarshierarkiet fragmenterer omsorgsarbejdet og udgrænser beboernes oplevelse af eget lægemiddelindtag.
Overuse of Medical Imaging in Low-Middle Income Countries: A Scoping Review
Authors: Protheroe Elizabeth
Published: July 2024

Purpose: The overuse of medical imaging is a key component of medical resource overutilization. Primary reasons for this include high costs, overdiagnosis, incidental findings and direct harms. Although the overuse of medical imaging is well-researched in high income countries, it is still unclear what evidence there is for the overuse of medical imaging in low-middle income countries (LMICs). Understanding the extent of medical imaging overuse in LMICs could encourage doctors and policymakers to address the problem of overuse, which may facilitate better use of limited resources.
Methods and Materials: A scoping review was performed according to the PRISMA Extension for Scoping Reviews Checklist. Electronic academic databases Medline via Ovid, Embase and CINAHL were searched for relevant studies.
Results: Forty studies were identified, with a total of 42,413 patient participants across 15 LMICs. Computed tomography (CT) scan was the most frequent imaging modality of study (20/40), followed by magnetic resonance imaging (MRI) (13/40), and ultrasound (US) (6/40). Guidelines were used as a tool to define imaging overuse in 58% (23/40) of the included studies. However, only 5% (2/40) of studies used local guidelines. The overall results of the review showed that 35% of MRI, 55% of CT, 40% of radiography, 62% of ultrasound and 12% of single-photon emission computed tomography (SPECT) investigations were recorded as an overuse.
Conclusion: The results of this study show that there is evidence for the widespread overuse of medical imaging in LMICs, including the overuse of CT, MRI, radiography, ultrasound and SPECT. The majority of studies demonstrated a lack of local imaging guidelines. Future research may focus on developing guidelines designed for the local disease epidemiology and the financial context of the locality, to better identify overuse and promote more contextually appropriate imaging practices.
Hyperglycaemia and outcome in neonates with hypoxic-ischaemic encephalopathy
Authors: Sichula M , Pillay S , Nakibuuka V , Harrison M , Horn A
Published: July 2024

Background. Hypoxic-ischaemic encephalopathy (HIE) remains a leading cause of death and disability in term neonates despite therapeutic hypothermia. Hyperglycaemia in the first 12 hours of life is associated with poor outcomes in some studies. This relationship has not yet been explored in South African (SA) cohorts.
Objective. To describe the association between hyperglycaemia (in the first 12 hours of life) and poor outcome, which was defined as death or a severely abnormal amplitude-integrated electroencephalogram (aEEG) at 48 hours, in neonates with moderate-to-severe HIE who were treated with hypothermia at an SA tertiary hospital.
Methods. Folders from a database of 57 neonates with moderate-to-severe HIE treated with hypothermia between January 2011 and December 2012, were reviewed to obtain glycaemic profiles. Maternal and neonatal characteristics and outcomes were extracted from the database.
Results. Only 47 neonates had adequate glucose and aEEG data. Seventeen neonates (36%) had hyperglycaemia (>8.3 mmol/L), 25 (53%) were normoglycaemic and 5 neonates (10%) were hypoglycaemic (<2.3 mmol/L). Hyperglycaemia was only associated with death or severely abnormal aEEG at a glucose value ≥25.6 mmol/L. Hyperglycaemia was significantly associated with a low 5-minute Apgar score (p=0.007), severely abnormal aEEG at 6 hours (p=0.029), and a higher HIE score at 6 hours (p=0.002). Hyperglycaemia was associated with death (odds ratio 10; 95% confidence interval 1 - 96; p=0.045), but the association was not independent of the 5-minute Apgar score.
Conclusion. Early hyperglycaemia in neonates with moderate-to-severe HIE was associated with disease severity at birth and death despite cooling.
Are end colostomies always contraindicated in anorectal malformations?
Authors: Brisighelli G , Theron A , Westgarth-Taylor C , Mapunda E
Published: July 2024

Background. In our clinical setting, a three-staged approach is consistently employed to manage patients with anorectal malformations (ARMs).
Objective. To evaluate the safety and feasibility of end-colostomies, in particular subtypes of ARMs.
Methods. The medical records of babies born with an ARM treated between 1 January 2017 and 31 December 2022 were reviewed. Information regarding the type of ARM, type of colostomy, complications during colostomy formation, posterior sagittal anorectoplasty (PSARP) and colostomy closure was recorded.
Results. Ultimately, 194 patients were included. Of those, 137 patients had divided colostomies with distal mucus fistulas (DC) and 57 had end-colostomies (EC). Ninety-seven patients (50%) had perineal and vestibular fistulas, including 40 (41%) patients with DC and 57 (59%) with EC. For post-colostomy formation, eight (20%) complications were recorded in the DC group and nine (16%) in the EC group (p=0.78). Wound sepsis presented in six patients with DC and four with EC (p=0.3). Nineteen percent (16/85) of patients who had PSARP developed complications, including 4/37 (11%) with DC and 12/48 (25%) with EC (p=0.16). Of the 72 patients who underwent stoma reversal, six (8%) had complications post-operatively: three in the DC group and three in the EC group.
Conclusion. For patients with rectoperineal and vestibular fistulas, where divided colostomies are not warranted, end colostomies provide a safe alternative.
First results of measuring temperature in snow cover at a winter search site in Irkutsk
Authors: Ianchenko (Yanchenko) Natalia Ivanovna , Antsiferov Evgenii Aleksandrovich
Published: July 2024

The article is devoted to the first results of monitoring the temperature in the snow cover, the height of the snow cover and the atmospheric air temperature in Irkutsk. The results were obtained on the basis of exploratory scientific and organizational research that began in 2021 at the INRTU sites using an autonomous automatic software and hardware complex developed at the Institute for Monitoring Climatic and Ecological Systems of the SB RAS. It has been established that there is a change in temperature in the snow cover at the same height during the day, while in the height range from 0 to 15 cm (0 cm is the underlying base) temperature fluctuations between min and max are insignificant compared to temperature fluctuations in the upper layers snow cover. It is shown that graphically changes in temperature in the snow cover at altitudes that are closer to the atmospheric surface of the snow cover have more pronounced amplitude daily cycles, in contrast to changes at low altitudes. A linear correlation has been established between air temperature and temperature at various heights in the snow cover; the correlation coefficient decreases with decreasing heights in the snow cover, provided that the maximum height of the snow cover is constant, for example, during the day. The phenomenon of cooling of the surface of the snow cover at certain hours during the day, when the temperature of the snow-atmospheric surface is lower than the air temperature, is shown. We note that actual values obtained in autonomous automatic real-time mode, such as air temperature, temperature and snow depth, may have practical significance and over time, with the development of digitalization, may be in demand for managing the urban ecosystem of the city and/or individual territories
Backlight and dim space object detection based on a novel event camera
Authors: Zhou Xiaoli , Bei Chao
Published: July 2024

Background

For space object detection tasks, conventional optical cameras face various application challenges, including backlight issues and dim light conditions. As a novel optical camera, the event camera has the advantages of high temporal resolution and high dynamic range due to asynchronous output characteristics, which provides a new solution to the above challenges. However, the asynchronous output characteristic of event cameras makes them incompatible with conventional object detection methods designed for frame images.

Methods

Asynchronous convolutional memory network (ACMNet) for processing event camera data is proposed to solve the problem of backlight and dim space object detection. The key idea of ACMNet is to first characterize the asynchronous event streams with the Event Spike Tensor (EST) voxel grid through the exponential kernel function, then extract spatial features using a feed-forward feature extraction network, and aggregate temporal features using a proposed convolutional spatiotemporal memory module ConvLSTM, and finally, the end-to-end object detection using continuous event streams is realized.

Results

Comparison experiments among ACMNet and classical object detection methods are carried out on Event_DVS_space7, which is a large-scale space synthetic event dataset based on event cameras. The results show that the performance of ACMNet is superior to the others, and the mAP is improved by 12.7% while maintaining the processing speed. Moreover, event cameras still have a good performance in backlight and dim light conditions where conventional optical cameras fail. This research offers a novel possibility for detection under intricate lighting and motion conditions, emphasizing the superior benefits of event cameras in the realm of space object detection.
Effect of carbon nanoparticles on the growth and photosynthetic property of Ficus tikoua Bur. plant
Authors: Chen Nian , Tian Xiaojian , Yang Mingli , Xu Jiajun , Tan Tinghong , Wang Jiyue
Published: July 2024

The application of nanomaterials in different plants exerts varying effects, both positive and negative. This study aimed to investigate the influence of carbon nanoparticles (CNPs) on the growth and development of Ficus tikoua Bur. plant. The morphological characteristics, photosynthetic parameters, and chlorophyll content of F. tikoua Bur. plants were evaluated under four different concentrations of CNPs. Results indicated a decreasing trend in several agronomic traits, such as leaf area, branching number, and green leaf number and most photosynthetic parameters with increasing CNPs concentration. Total chlorophyll and chlorophyll b contents were also significantly reduced in CNPs-exposed plants compared to the control. Notably, variations in plant tolerance to CNPs were observed based on morphological and physiological parameters. A critical concentration of 50 g/kg was identified as potentially inducing plant toxicity, warranting further investigation into the effects of lower CNPs concentrations to determine optimal application levels.