bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anorthite-reducing glass-crystalline materials synthesized in plasma
Authors: Shekhovtsov V V , Skripnikova N K , Semenovykh M A , Bakshanskii R Yu 
Published: November 2021

Abstract
The paper presents the experimental results of the glass-ceramic material production using the low-temperature plasma. The dependences are suggested for the main physical-and-mechanical properties (compressive and flexural strengths, density, linear thermal expansion coefficient) of products and the mixture compositions. The centers of secondary recrystallization are identified for the anorthite phase (CaAl2Si2O8). These inclusions chaotically locate on the surface of the synthesis products and resemble dendritic microinclusions up to 90 nm in size. A comparative analysis is given to the properties of glass-ceramic materials produced by the low-temperature plasma and traditional methods.
Simulation of charged particle beam dynamics extracted from a plasma source
Authors: Kanshin I A 
Published: November 2021

Abstract
This paper presents the results of computer simulation in COMSOL Multiphysics of the hydrogen isotopes beam dynamics extracted from a plasma source of small linear accelerator. The beam energy was 100 keV. The simulation was carried out taking into account the charge exchange of ions on neutral gas molecules in the accelerating system. At the same time, the calculations took into account the process of secondary ion-electron emission from the surfaces of the accelerating system that are bombarded with both fast and slow ions. Consideration of this process made it possible to determine that the value of the electronic load is at least 50% of the main beam current of 100 μA. The inclusion in the trajectory analysis the magnetic field simulation in the secondary electrons generation area made it possible to determine the magnetic field strength, which effectively blocks secondary electrons on the target (3000 Gauss). Then it has been experimentally demonstrated that the discharge current in a plasma source automatically increases by 20% when using the magnetic suppression system on the target node (magnetic field strength is 3000 Gauss).
Measurement of the electron beam energy in a source with a plasma anode and the beam extraction into the atmosphere through a foil window
Authors: Abdullin E N , Basov G F 
Published: November 2021

Abstract
Measurements of the energy of an electron beam in an electron beam source with an explosive-emission cathode, a plasma anode and a foil window, providing the extraction of an electron beam with a cross-section of (100–200) cm2 into the atmosphere, have been performed. The high voltage source was a Marx generator based long lines with matched loads. The energy values were calculated from the results of measurements of the temperature of a beam collector placed in vacuum using thermistors and an infrared imager. At an accelerating voltage of ~ 200 kV, a current of (1–2) kA, and an electron beam duration of 5 μs, the maximum values of the energy released in the collector with a cross section of 74 cm2 were (650–850) J/pulse. A decrease in the current and energy of the beam was recorded approximately by a factor of two after passing through an AMG-2n aluminum-magnesium foil with a thickness of 30 μm. The use of infrared imager for recording the beam structure in the plane of the output window in air has been tested.
Efficiency of electron beam extraction to the atmosphere in an accelerator based on ion-electron emission
Authors: Doroshkevich S Yu , Vorobyov M S , Torba M S , Koval N N , Sulakshin S A , Levanisov V A , Ekavyan A A , Chistyakov A V 
Published: November 2021

Abstract
The use of a modern element base makes it possible to create power supplies with a transition from a direct mode of generation of an auxiliary discharge to a pulse-periodic mode with a pulse repetition rate at the level of several tens of kHz. This allows for a more flexible adjustment of the discharge parameters, keeping the average value of its current, but changing its amplitude with a corresponding change in the pulse duty cycle. In this work, using an electron accelerator based on ion-electron emission, generating a wide-aperture electron beam, we research the effect of auxiliary discharge generation mode (direct and pulse-periodic) on the efficiency of electron beam extraction into the ambient atmosphere. It is shown that, in a direct mode of electron beam generation at an accelerating voltage of 150 kV, the beam extraction coefficient does not exceed 0.25. The possibility of increasing the extraction coefficient to K = 0.55 at the same accelerating voltage of 150 kV was demonstrated without making changes to the design of the accelerator, but switching to a pulsed-periodic mode of emission plasma generation.
Effect of extinction beam-plasma discharge while the injection thermoelectrons during transportation of the electron beam in the forevacuum pressure range
Authors: Zenin A A , Bakeev I Y , Klimov A S 
Published: November 2021

Abstract
The article presents the results of experiments aimed at studying the effect of low-energy thermoelectrons on the parameters of the beam plasma and plasma of the beam-plasma discharge generated during the transportation of a powerful electron beam in the pressure range of the medium vacuum. It is shown that the injection of a sufficiently small current of low-energy thermoelectrons is capable of violating the conditions for the combustion of the beam-plasma discharge and reducing the power loss of the electron beam for SPR generation. In this case, the plasma concentration decreases by almost an order of magnitude (to 1015 m–3) and the temperature of plasma electrons decreases by almost three (to 0.3 eV).
Features of glow discharge ignition through a small hole in the hollow cathode of a large volume
Authors: Klimov A S , Bakeev I Y , Zenin A A 
Published: November 2021

Abstract
The influence of the size of a cathode gap on the initiation of the effect of a hollow cathode in a glow discharge system with an extended hollow cathode in the forevacuum pressure range is shown. It was found that the threshold current for the transition of the discharge to the burning mode with a hollow cathode is determined by the ratio of the longitudinal and transverse dimensions of the cathode slit. With a decrease in the width of the slot, the threshold current increases disproportionately; at the same time, with an increase in the length of the slot, this current sharply decreases.
Effect of working gas pressure on mass-to-charge composition of plasma ions in high-current planar magnetron discharge
Authors: Shandrikov M V , Vizir A V , Klimov A S , Oks E M , Frolova V P 
Published: November 2021

Abstract
The mass-to-charge ion composition of a planar magnetron discharge plasma has been investigated. The measurements used a modified quadrupole mass-spectrometer and a time-of-flight spectrometer. The experiments were carried out on a copper magnetron target. Argon was used as a working gas. The operating pressure was 0.15÷1.3 Pa. The discharge current was 1÷20 A with a pulse duration of 30÷50 μs. The influence of main operating parameters (discharge current and working gas pressure) on mass-to-charge composition of plasma ions was measured. The mass-to-charge composition of plasma ions in the axial direction was measured as a function of working pressure. Plasma electron temperature was measured and its effect on the mass-to-charge composition of magnetron plasma ions was estimated.
Influence of accelerating gap configuration on parameters of a forevacuum plasma-cathode source of pulsed electron beam
Authors: Kazakov A V , Medovnik A V , Oks E M , Panchenko N A 
Published: November 2021

Abstract
The research of influence of accelerating gap configuration on parameters of a forevacuum plasma-cathode source of a pulsed low-energy (up to 10 keV) large-radius electron beam is presented. An increase in cell sizes of a mesh emission electrode increases electron emission efficiency, but leads to a decrease in electric strength of an accelerating gap. Larger cell sizes of a mesh extractor provide higher electron beam current. An increase in the length of the accelerating gap first leads to an increase in the electron emission efficiency, but when optimal value is reached, a further increase in the length leads to a decrease in the emission efficiency. This optimal length of the accelerating gap is about 25 mm. However, the electron emission efficiency changes relatively small (within 15%). The dependencies of maximum emission current and maximum operating gas pressure on the length of acceleration gap is similar to the dependence for the emission efficiency, but the gap length much stronger influences on these maximum values. Moreover, the optimal length, at which maximum emission current or maximum pressure is provided, is depended on gas pressure (for current) or emission current (for pressure), accelerating voltage and pulse duration.
Influence of electron emission on operation of a constricted arc discharge in a pulsed forevacuum plasma-cathode electron source
Authors: Kazakov A V , Oks E M , Panchenko N A 
Published: November 2021

Abstract
The research of influence of electron emission and processes associated with the formation of a pulsed large-radius electron beam on operation of a constricted arc discharge, which forms emission plasma in a forevacuum plasma-cathode electron source, is presented. Processes, occurring in case of generation of the electron beam at forevacuum pressure range 3–20 Pa, provide lower operating voltage of the constricted arc discharge. The constricted arc voltage decreases with increasing pressure and increasing accelerating voltage. However, at pressure more than 15 Pa, the arc voltage decreases until a certain minimum value is reached, and then arc voltage is almost independent on pressure and accelerating voltage. This minimum value of the constricted arc voltage is on average 1.5–2 times higher as compared with voltage of the cathodic arc at the same discharge current. The observed decrease of operating voltage of the constricted arc is most likely caused by accelerated back-streaming ions, which move toward the emission electrode from beam-produced plasma. These accelerated ions partially penetrate into the hollow anode of discharge system through the mesh emission electrode and facilitate formation of the arc plasma, and thus provides lower voltage of the constricted arc.
Investigation of a cold atmospheric plasma jet generation in single and multichannel planar devices
Authors: Gugin P P , Zakrevsky D E , Milakhina E V 
Published: November 2021

Abstract
A plasma source of atmospheric pressure with a planar geometry of the device and an adjustable number of planar discharge channels has been developed. The dependence of the recorded collector current on the amplitude of the applied voltage is investigated. It was found that the current in each of the channels consists of a set of independent current channels whose propagation does not depend on each other.
Optimum transfer characteristics of the Tesla transformer on the first and second half-waves of output voltage
Authors: Kladukhin V , Khramtsov S 
Published: November 2021

Abstract
The elements of the theory of the Tesla transformer are stated, the exact solution of the equations of the dynamics of currents and voltages in the transformer circuits through the generalized parameters of the circuits (Q-factors of the primary and secondary circuits, the coupling coefficient of the circuits and mismatching factor of the natural resonance frequencies of the circuits) is given, under the assumption of their constancy. The optimal transfer characteristics of the processes of charging the capacitive storage of the secondary circuit of the transformer on the first and second half-waves are given, demonstrating the capabilities of the Tesla transformer.
Identifying drug-resistant tuberculosis from chest X-ray images using a simple convolutional neural network
Authors: Ureta J , Shrestha A 
Published: November 2021

Abstract
Tuberculosis(TB) is one of the top 10 causes of death worldwide, and drug-resistant TB is a major public health concern especially in resource-constrained countries. In such countries, molecular diagnosis of drug-resistant TB remains a challenge; and imaging tools such as X-rays, which are cheaply and widely available, can be a valuable supplemental resource for early detection and screening. This study uses a specialized convolutional neural network to perform binary classification of chest X-ray images to classify drug-resistant and drug-sensitive TB. The models were trained and validated using the TBPortals dataset which contains 2,973 labeled X-ray images from TB patients. The classifiers were able to identify the presence or absence of drug-resistant Tuberculosis with an AUROC between 0.66–0.67, which is an improvement over previous attempts using deep learning networks.
Computer-aided Detection of Lung Tumors in Chest X-ray Images Using a Bone Suppression Algorithm and A Deep Learning Framework
Authors: Sato K , Kanno N , Ishii T , Saijo Y 
Published: November 2021

Abstract
Detecting lung tumors in early stage by reading chest X-ray images is important for radical treatments of the disease. In order to decrease the risk of missed lung tumors, diagnosis support systems that can provide the accurate detection of lung tumors are in high demand, and the use of artificial intelligence with deep learning is one of the promising solutions. In our research, we aim to improve the accuracy of a deep learning-based system for detecting lung tumors by developing a bone suppression algorithm as a preprocessing for the machine-learning model. Our bone suppression algorithm was devised for conventional single-shot chest X-ray images, which do not rely on a specific type of imaging systems. 604 chest X-ray images were processed using the proposed algorithm and evaluated by combining it with a U-net deep learning model. The results showed that the bone suppression algorithm successfully improved the performance of the deep learning model to identify the location of lung tumors (Intersection over Union) from 0.085 (without the bone suppression algorithm) to 0.142, as well as the ability to classify the lung cancer (Area under Curve) that increased from 0.700 to 0.736. The bone suppression algorithm would be useful to improve the accuracy and the reliability of the deep learning-based diagnosis support systems for detecting lung cancer in mass medical examinations.
Synthesis and Characterization of Electrospun Polyvinylidene Fluoride-based (PVDF) Scaffolds for Renal Bioengineering
Authors: Sta. Agueda J R , Madrid J , Mondragon J M , Lim J , Tan A , Wang I , Duguran N , Bondoc A 
Published: November 2021

Abstract
With the continuous search for alternative treatment for End Stage Renal Disease (ESRD), the use of synthetic scaffolds as a prospect is becoming a forefront in regenerative medicine. This study aimed to fabricate and evaluate the effects of varying electrospinning parameters (the applied voltage, spinning distance and flowrate) to the fiber diameter and pore size of the scaffolds produced using polyvinylidene fluoride (PVDF). Electrospun scaffolds were subjected to scanning electron microscopy (SEM) and strain apparatus to assess structural and tensile properties. Results showed that applied voltage, spinning distance, and flowrate directly affect the overall pore size and fiber diameter of the electrospun scaffolds, as well as resulting in a direct effect to the tensile strength of the electrospun scaffold. The optimal values for the parameters in fabricating a PVDF electrospun scaffold would be a voltage of 20kV, a spinning distance of 100mm and a flowrate of 0.5ml/h. Results also show that spinning distance and flowrate have statistically more impact on the outcome of the fiber diameters, while applied voltage and spinning have statistically more impact on the outcome of the pore sizes. Moreover, the electrospun scaffolds acquired thinner fiber diameters and smaller pores sizes when compared to that of the native kidney tissue. Nonetheless, the promising mechanical integrity of the electrospun PVDF-based scaffolds offer a potential approach to addressing ESRD.
The Influences of Sintering Process on the Characteristics of Corbiculacea (Etok) Shells Based Hydroxyapatite Powder
Authors: Roslan M R M , Nasir N F M , Mohammad N F , Meng C E , Mohamed M S , Abdullah M N 
Published: November 2021

Abstract
Hydroxyapatite (HA) powders were prepared via chemical solution through aqueous solution of calcium hydroxide and phosphoric acid. The calcium precursor was extracted from the calcium carbonate of Corbiculacea shells while the phosphate precursor originated from the commercially available phosphoric acid. The final product of HA powders is then manipulated through the sintering process at 500°C while the other sample was used as it is. XRD result shows significant changes in its crystallinity, crystallite size and lattice parameters after the sintering process. By sintering the HA, the crystallite size and crystallinity were increases as much as 6.25% and 5.31% respectively. SEM on the other hand showed different morphology for both sintering and non-sintering HA powders. For the sintering HA, the grains size is higher which is 5.00μm compared to non-sintering HA which is 3.91μm due to the agglomeration.
Synthesis Methods of Doped Hydroxyapatite: A Brief Review
Authors: Baskaran Thivya , Mohammad Nur Farahiyah , Md Saleh Siti Shuhadah , Mohd Nasir Nashrul Fazli , Mohd Daud Farah Diana 
Published: November 2021

Abstract
Hydroxyapatite (HA) has drawn great attention to biomedical applications due to their bone mineral similarity, strong bioactivity, biocompatibility and osteoconductive. Despite the fact that HA has many advantages, several properties are still lacking, emphasising the crucial need for ion doping/substitution. Many attempts have been made to incorporate ions into HA structure to increase their physical, chemical, and biological properties. With such a diverse range of methods available for the synthesis of doped HA, this article discussed the importance of doping for HA and summarizes four common techniques used to prepare doped hydroxyapatites which include precipitation, hydrothermal, sol-gel and mechanochemical method.
Synthesis and Characterization of Nanoporous Biphasic Calcium Phosphate
Authors: Mohammad Nur Farahiyah , Mei Koo Li , Mohd Roslan Mohd Riza , Md Saleh Siti Shuhadah , Mohd Daud Farah Diana 
Published: November 2021

Abstract
For the past few years, many researchers are focusing on biomaterials fabrication in porous form. The research on porous calcium phosphate has been investigated due to its excellent biocompatibility and better osseointegration. This research paper presented nanoporous biphasic calcium phosphate (BCP) synthesised using chemical precipitation method. Triblock co-polymer F127 was used as pore directing agent. The chemical compositions of pure BCP samples were examined using X-ray diffraction (XRD) analysis which shows common peak of BCP. The pore size distribution (PSD) on the other hand shows that the pore size of the samples mainly distributed at 52.8 nm, 49.6 nm and 32 nm. BCP pellets were soaked in phosphates buffered saline (PBS) and distilled water (DW) for 15 days. The pH of the soaking medium decreases throughout the soaking period due to degradation of BCP pellets, which release hydrogen ions into the PBS and distilled water. BCP degrades faster in distilled water than in PBS. After soaking for 15 days, materials were examined with a scanning electron microscope (SEM) to assess the morphological structure before and after in vitro degradation. Apatite formation was discovered on the surface of the BCP pellet that had been immersed in the PBS solution.
Antibacterial Activity of Biodegradable Plastic from Chromolaena odorata (Pokok Kapal Terbang) Leaves
Authors: Mohamad C W S R , Cheng E M , Talib N A Abu 
Published: November 2021

Abstract
The aim of this research project was to develop antimicrobial films from blends of C. odorata and PVA and test the films for microbial activity using broth dilution methods for Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria. The result shows that CO/PVA80 successfully inhibit the growth of target bacteria. In antibacterial activity analysis, CO/PVA80 showed 50% higher compare with pure PVA film, PVA100. Other than that, the high percentage of PVA in the blend films, the greater the thickness, Tensile Strength (TS) and Young’s Modulus (YM), while the Elongation Break (EB) of the prepared films decreased. The 0.5 mm CO/PVA80 film shows a good result in mechanical properties which is TS 6.55 MPa, YM 182 MPa and EB is 7.47%. A CO/PVA80 were show a smooth texture, lacked of macropore and good characteristic with a SEM analysis. These results suggest that CO/PVA80 films have good compatibility to form an antimicrobial film as a new material for medical application especially for wound healing.
Customized Designs and Biomechanical Analysis of Transtibial Prosthetic Leg
Authors: Mubarak A J M , Rashid A M A , Wahab A A , Seng G H , Ramlee M H 
Published: November 2021

AbstractA prosthetic leg is a technical mechanism that is designed as a substitution of the function of a missing limb or body part. This device has been effectively used as an essential tool for amputees. The traditional way of producing the prosthetic leg is very tedious and time consuming. Apart from that, comfortability issue is another problem if using casting method. Therefore, the main purpose of this study is to customize and biomechanically evaluate an prosthetic’s socket to produce a better construct for the improvement of performance. In this paper, the methods started with a definition of the construction of the finite element model which is divided into four parts: amputee leg, sockets model, pylon and socket. Later, modelling of the pylon and three-dimensional foot model was taken into consideration. The focus was on the design of the socket then moving to the biomechanical study using a finite element method which involved several analyses of the effects of socket designs as well as its material properties. The sockets were initially developed from a data of 3D scanning with an estimated uniform thickness of 5 mm. The results of the finite element study showed that the perforated socket configuration had better stability in terms of displacement (0.19 mm) and von Mises stress (1.15 MPa), as compared to the conventional socket (stress of 3.22 MPa), and the displacement of 0.19 mm. Meanwhile, open-sided socket experienced von Mises stress of 1.18 MPa and displacement of 0.22 mm. In conclusion, a customized design is a promising technique that can enhance the performance of user in terms of biomechanical aspect.