bluuebunny/crossref_metadata_2025 huggingface dataset:
Conductivity of a superlattice based on the semi-Dirac crystals
Authors: Kryuchkov S V , Kukhar E I , Nikolaeva L N
Published: December 2020

The current-voltage characteristic of a superlattice based on the semi-Dirac crystals has been studied. The case of the absence of a gap between valence and conduction mini-band has been considered. Such a superlattice has been shown to be characterized by both semi-metal and narrow-band semiconductor electrical properties. From the one hand there is the point in the Brillouin zone close to which the depletion of the states occurs without gap opening. From the other hand there is the portion of negative differential conductivity in the current-voltage characteristic. The dependences of longitudinal conductivity and maximum of the current-voltage characteristic on the Fermi energy have been investigated.
Scattering of spatially bounded X-ray beams in lateral periodic structures
Authors: Kazakov D V , Punegov V I
Published: December 2020

The dynamical theory of X-ray diffraction is developed to the case when the incident and reflected X-ray beams are spatially bounded. X-ray diffraction in complicated lateral periodic structures is considered. Effects, due to periodic regular elastic deformations of a crystal lattice on an angular distribution of the scattered intensity, are investigated. Using the found solutions, numerical simulations of reciprocal space maps for crystals with periodically distributed elastic strains were performed. It was established, that for crystals modulated by a surface acoustic wave, diffraction orders consist of the main reflection vertical band and a pair of inclined bands, induced by spatially bounded X-ray beams. In the case of diffraction in crystals with the surface grating, one observes additional satellites along inclined bands caused by the spatial modulation of incident X-ray wave. Results of X-ray diffraction on a crystal modulated by a surface acoustic wave and on a crystal with a metal surface grating are presented.
THz gas discharge in nitrogen as a source of ultraviolet radiation
Authors: Sidorov A V , Glyavin M Yu , Luchinin A G , Razin S V , Vodopyanov A V
Published: December 2020

This work presents the results of investigation of THz gas discharge in inhomogeneous flow of nitrogen. As a source of sub-millimetre radiation we used 40 kW@670 GHz gyrotron created in IAP RAS. It is shown that, despite the tendency of the discharge in electromagnetic wave beams to propagate towards the heating radiation from the breakdown region, in the case of a strongly inhomogeneous gas flow (nitrogen in our case), conditions can be created under which the discharge practically does not propagate and becomes point-like. The features of the glow of a THz discharge in a nitrogen flow in a wide range of background gas pressures are studied. The presence of a powerful afterglow in some bands of the second positive system of nitrogen at high pressures was demonstrated. The prospects of using such a discharge as a source of UV radiation are discussed.
Etching of Si3N4 by SF6/H2 and SF6/D2 plasmas
Authors: Pankratiev P A , Barsukov Yu V , Kobelev A A , Vinogradov A Ya , Miroshnikov I V , Smirnov A S
Published: December 2020

Selective plasma etching of silicon nitride (Si3N4) over silicon oxide (SiO2) is one of critical steps in the nanofabrication processes, where a direct plasma etching of Si3N4 is required for some applications. It was reported recently that Si3N4 etching by remote plasma source can be initiated by the vibrationally excited HF(v) molecules at the low concentration of atomic fluorine. Generally, the main source of HF(v) in plasma is reaction of atomic fluorine with H2 molecule. Due to this fact, the kinetic isotope effect should be observed during Si3N4 etching if replace the H2 source gas on deuterium gas (D2). The data presented here are the Si3N4 and SiO2 etching by the SF6/H2 and SF6/D2 plasmas. A different amount of H2 and D2 have been added to the SF6 discharge during the Si3N4 and SiO2 etching. It was shown that at low H2/D2 flow rate the Si3N4 etch rate is lower in the SF6/D2 discharge. This one confirms the hypothesis about Si3N4 etching by HF(v) and indicates on the fact that HF(v) gives contribution to Si3N4 etching by the direct plasma (not only by the remote plasma) at relatively high concentration of atomic fluorine.
Self-excited periodic oscillations in a supersonic laminar flow past a blunt-fin body mounted on a plate
Authors: Kolesnik E V , Smirnovsky A A , Smirnov E M
Published: December 2020

Results of numerical simulation of supersonic gas flow past a blunt fin mounted on a flat plate with developing laminar boundary layer are presented. The calculations cover flow cases with the freestream Mach number of 6.7 and three different Reynolds numbers. A detailed analysis of flow characteristics such as temperature and surface heat flux are presented. In the smaller Reynolds number case, solution is steady-state and agrees very well with known numerical and experimental data. In case of larger Re values, the flow becomes periodic. These regimes are characterized by self-excited non-linear oscillations with almost the same fundamental frequency.
Numerical simulation of the spatio-temporal evolution of the flow in the model of abdominal aorta bifurcation with stenosis in the one of the common iliac arteries
Authors: Sinitsina D E , Zaitsev D K
Published: December 2020

The structure of the pulsating flow in the model of the average configuration, including the bifurcation of the abdominal aorta and subsequent bifurcation of the iliac arteries with axisymmetric hemodynamically significant stenosis in the right common iliac artery, is researched by numerical method. It has been shown that the presence of stenosis in this artery affects the flow structure both downstream and upstream: reverse-flow zones are formed and transverse flow evolution differs significantly from the structure of the flow in a healthy branch. The stenosis with the spatial curves of the model leads to the formation of a stable single-vortex flow in the external iliac artery most of the cardiac cycle. In the mentioned artery of the healthy branch various unstable patterns of two-vortex structure form during the cycle. In both internal iliac arteries, there is a transitional flow, from a two-vortex to a single-vortex motion, forms during the cycle. The influence of the presence of stenosis on the structure of the transverse flow in the internal iliac artery is insignificant. The most likely regions for atherosclerotic lesions of the vascular wall, characterized by the minimum values of time-averaged wall shear stresses and the maximum values of oscillatory shear index, are the stenosis region and the external wall of the common iliac artery.
Calibration algorithm for semiconductor gas sensors and determination of volatile hydrocarbon concentrations in atmospheric air using Fourier transforms
Authors: Kazakov S A , Grevtsev M A , Khavrov G D
Published: December 2020

A calibration algorithm and an algorithm for measuring the concentrations of volatile hydrocarbons in atmospheric air using Fourier transforms for semiconductor gas sensors have been developed. This work presents experimental data on sensor calibrations obtained on certified equipment using gasoline, solvent vapor, toluene, and methane as an example. The calibration carried out by recording measurements of the electrical conductivity of the gas-sensitive layer of the sensor over time, both during heating and cooling samples of sensors based on samarium sulfides and other composite materials. The method of semiconductor gas Fourier spectroscopy that we are developing, the construction principles of which are described in recent publications, is based on the relationship of the obtained calibration characteristics of the sensors of volatile hydrocarbons concentration contained in atmospheric air, with the electrophysical characteristics of samarium sulfide based rare earth semiconductors used as gas sensitive layers.
Self-oscillations of the cutting cutters
Authors: Karpachev A Y
Published: December 2020

The design and construction of products that are subjected to variable forces during operation should be based on calculations of the dynamic properties of the structures being created. This applies most to structures that contain thin-walled elements. In this regard, the development of a reliable method for determining the own dynamic characteristics of cutting tools in the form of cutting circles and cutters is relevant.An engineering method for calculating the frequencies and forms of natural oscillations of disk cutting mills of variable thickness in the radial direction is considered. The results of the calculation were confirmed by the proposed method using data from experiments conducted using unique modern equipment. Thus, it was established that the proposed method can be applied to the analysis of the dynamic properties of the considered type of disk cutting tools and their design with the specified dynamic characteristics. The results obtained are necessary for evaluating the critical operating conditions of the mills under study.
Stabilization of first integrals in optimal control problem
Authors: Kaspirovich K Z
Published: December 2020

The paper considers methods for solving the variational problem of implementing control that stabilizes the optimal movement of the rocket in gravitational fields, finding the most accurate trajectories, and applying the results to solve various practical problems of flight dynamics. The relevance of the study of these problems is due to the fact that space guidance and tracking of the object’s trajectory during the entire flight is the most important basis for a successful space maneuver of ships, satellites, and missiles. Building and implementing in practice the laws of Autonomous guidance in application to modern types of propulsion technology is an acute unsolved problem today, which depends on the ability of aircraft engines to produce the necessary thrust for flight. It takes into account the fact that in reality the object does not fly along the specified trajectory, but has a certain deviation due to inaccuracies in the parameters of the flight model and the propulsion system. Therefore, it is necessary to set the stabilization problem in order to find optimal control conditions. The problems of stabilization and traffic control are important both from a theoretical point of view and because of numerous technical applications. From a theoretical point of view, these problems are important primarily because they relate to complex problems of mechanics, and each time they require new approaches and methods for their solution. In this case, the nature of the problem of motion stabilization depends significantly on the additional conditions that are imposed on the dynamic system.
Displacements of Points of a Viscoelastic Ball Caused by Tides
Authors: Zlenko Aleksandr
Published: December 2020

The derivation of equations of motion is considered in the problem of motion of two viscoelastic bodies in the central gravitational field of massive spherical rigid homogenous body with the help of the d’Alembert Lagrange variation principle. It was used the Kelvin– Voigt model of viscous forces and classical theory of small strains. The method for separation of motions was applied in order to get an approximate solution of quasi-static equation of the theory of elasticity on the unperturbed motion. There were obtained the displacements of each point of the bodies, caused by centrifugal, elastic and dissipative forces.
Optimizing the Forecast Interval for Determine the Parameters of the Earth Pole Motion Model
Authors: Shabunina A.A. , Filippova A.S.
Published: December 2020

The paper provides a solution to the problem of determining the parameters of the model of the Earth pole motion that are optimal from the point of view of the standard deviation. The choice among the considered models is made according to the most accurate forecast on the different time intervals, and the estimate of the approximation interval duration is given that should be used to determine the unknown model parameters from the observational data
Research of Optical Interconnection Technology in Datacenter Networks
Authors: Hao Tianchun
Published: December 2020

In recent years, with rapid development of cloud computing, the business volume of datacenter has increased unprecedentedly and the development of datacenter is facing great challenges. At this point, more efficient interconnection schemes are needed to maintain the increasing demand for communication bandwidth. With its great bandwidth advantage, optical fiber provides low-loss and low-cost solutions for telecom networks. At the same time, compared with the electric interconnection based on copper wire, optical switching technology greatly improves the transmission rate of the communication network. In this paper, the interconnection structure of the datacenter network is studied. Aiming at the interconnection for different top-of-racks (ToR), the c-Through and Helios structures based on photoelectric hybrid technology are reported. Moreover, some structures based on all-optical interconnection such as Proteus, OSMOSIS and IRIS are mentioned. For the interconnection in ToR, arrayed waveguide grating (AWG) based passive optical interconnection and the passive optical couplers-based interconnection schemes are described. Meantime, the main principles, advantages and disadvantages of various structures are analyzed. Finally, the future development of optical interconnection applications is stated.
Analogy of support vector machine and linear regression models in surface roughness prediction
Authors: Hweju Z. , Abou-El-Hossein K.
Published: December 2020

Accurate surface roughness prediction models are an indispensable part of an automated manufacturing system. Since most of the studies on surface roughness prediction have focused on large datasets, it is necessary to shift the focus towards the effectiveness of these models on small datasets. Thus, this study is an analogy of Support Vector Machine (SVM) and Linear Regression Models in surface roughness prediction of single point diamond turned RSA443, using a small dataset. Taguchi’s L9 orthogonal array-based experimental results from single point diamond turning of RSA443 have been integrated into the SVM model development. Primary cutting parameters (cutting speed, feed, and depth of cut) have been utilized, while a fine Gaussian SVM classifier is introduced for the analysis of the input features and surface roughness prediction using the MATLAB classification learner toolbox. The results indicate that the linear regression model is superior to the fine Gaussian SVM model. However, the high prediction accuracy of the fine Gaussian SVM model confirms the suitability of the model as an alternative surface roughness prediction tool. Hence both models can be reliably used for surface roughness prediction of RSA443 using small datasets.
Bubble Deck Slab as an Innovative Biaxial Hollow Slab – A Review
Authors: Siti Quraisyah A A Dyg , Kartini K , Hamidah M S , Daiana K
Published: December 2020

Slab is the most important member in any building structure which consume large amount of concrete. The slab self-weight is large due to large consumption of concrete in producing slab. Therefore, bubble deck slab is an innovative and newly designed biaxial hollow slab system that had been introduced in order to overcome this problem. Bubble deck slab is a revolutionary method which was developed by Jorgen Bruenig from Denmark in the 1990s. The bubble deck slab had been designed and constructed with plastic hollow bubbles in the middle part of slab to eliminate the concrete which does not perform any structural function and at the same time reducing the slab self-weight. Thus, the self-weight of bubble deck slab can be reduced about 30-50% than conventional concrete slab; that can reduce the loads acting on columns, walls and foundations. Finally, the use of bubble deck slab can give many benefits as compared to conventional concrete slab such as improve the structural performance of slab, reduce the materials and cost, efficiency and faster construction time, and it is also a green product. The aim of this paper is to give some of the reviews from previous studies related to bubble deck slab.
Effect of carbon fiber nanostructure on surface morphology under high-fluence ion irradiation
Authors: Andrianova N N , Borisov A M , Makunin A V , Mashkova E S , Ovchinnikov M A , Vysotina E A
Published: December 2020

The results of experimental study of the surface nano-and microstructuring of polyacrilonitrile (PAN) based carbon fiber VMN-4 and viscose based carbon cloth TGN-2MK under 30 keV Ar+ irradiation are presented. Scanning electron microscopy shows a strong difference in evolution of ion-induced morphology for these two carbon fiber types. At sufficiently high fluences, a corrugated morphology is formed on the PAN based carbon fiber, while a network of nanowalls is formed on the viscose based carbon fiber. The found differences are associated with a significant effect of the structure of the surface layer of carbon fiber on ion-induced dimensional changes.
Ion-plasma modification of the surface of light fiber materials
Authors: Andrianova N N , Borisov A M , Krit B L , Mashkova E S , Ovchinnikov M A , Timofeev M A , Umarov F F
Published: December 2020

The results of experimental study of the irradiation under 30 keV Ar+ with the temperature ∼250 °C of viscose based carbon cloth TGN-2MK and SU-2500 glassy carbon are presented. According to the scanning electron microscopy and Raman spectroscopy, modified layer of TGN-2MK obtained by ion irradiation is similar of modified layer of the glassy carbon in the structure and morphology. The formation of nanoscale wall in both cases occurs during graphitization under conditions of dynamic annealing of radiation damage.
Effect of bias voltage on texture formation in TiN, ZrN, Ta, Nb and W coatings
Authors: Betsofen S Ya , Petrov L M , Lozovan A A , Lenkovets A S , Grushin I A , Lebedev M A
Published: December 2020

The effect of the reference voltage on the texture in TiN, ZrN, Nb, Ta and W coatings obtained by PVD methods was investigated by X-ray method. It is shown that an increase in the reference voltage leads to an increase in the {111} texture to a weakening of this texture in W coatings. The results were interpreted on the basis of the features of elastic anisotropy in the material of coatings with a cubic lattice.
Nondestructure diagnostics of surface layers elements content for cylindrical shape material objects
Authors: Egorov V K , Egorov E V
Published: December 2020

The methodics background for the nondestructive element concentration diagnostics of cylindric shape material objects surface layer is developed. The diagnostics is produced without objects form-factor distortion on base of ion beams and X-ray analytical methods. The depth element concentration distribution determination found on the ion beams Rutherford backscattering data and results of X-ray fluorescence testing in conditions of TXRF modified measurements. Possibilities of the elaborated analytical conception are illustrated by experimental data obtained at study of element content in surface layer of the nuclear heat release cell shell.
Effects of different nanoparticles additions on composition and properties of oxide layers formed by plasma electrolytic oxidation on cast Al-Si alloy
Authors: Polunin A V , Borgardt E D , Shafeev M R , Katsman A V , Krishtal M M
Published: December 2020

The effect of additions to the electrolyte of SiO2, Si3N4, Y2O3, WC and TiC nanoparticles (NPs) with a similar particle size on the structure, composition and properties of oxide layers formed by plasma electrolytic oxidation (PEO) on a cast Al-Si alloy 357.0 (7.5 wt % Si) was investigated. The oxide layers were studied by scanning electron and confocal laser microscopy (SEM and CLSM), energy dispersive X-ray microanalysis (EDXMA), X-ray diffraction analysis (XRD), and instrumental indentation. The thickness, roughness, microhardness and wear resistance of the oxide layers were determined. A complex positive effect of all types of particles added to the electrolyte on the hardness and wear resistance of the oxide layers has been established. The greatest positive effect was exerted by the addition of tungsten carbide NPs to the electrolyte – an increase in the average microhardness from 882 MPa in the base version to 1354 MPa and a decrease in the average reduced wear from 592 ng/(N*m) to 65 ng/(N*m), respectively.
Starch based antimicrobial food packaging film towards a sustainable environment
Authors: Mallick N , Pal D , Soni A B , Jhariya D C , Singh D
Published: December 2020

Smart biodegradable packaging materials help restrict food-borne pathogens and reduce wastage of food items. Normally, food is packaged in plastic films, which are seldom reprocessed, which ultimately leads to an adverse impact on the environment. However, our ecosystem can be preserved by the use of biodegradable packaging materials. Deterioration of food caused by food-borne pathogens and microorganisms represent a severe problem. Therefore, a highly encouraging active packaging innovation is the antimicrobial packaging. Various active compounds can be incorporated in the packaging film to extend the shelf-life of packaged foods. The starch-based film is considered as a cost-effective material for antimicrobial packaging. Moreover, essential oils can be incorporated to enhance the antimicrobial effect, i.e., slow down food-borne pathogens. This paper systematically examines the impact of three essential oils (cloves, basil, and cinnamon) on biodegradable starch-based film’s antimicrobial action. Three pathogenic microorganisms, namely; Staphylococcus aureus, Bacillus cereus, and Escherichia coli were are used for the assessment of antimicrobial properties. All the films containing different essential oils have shown a significant antimicrobial action against all the three microbes studied in this work.
Special aspects of uranium oxide non-stoichiometry measurement by thermogravimetric analysis
Authors: Tenishev A , Kuzmin R , Matvenov M , Mikhalchik V , Shornikov D
Published: December 2020

Thermogravimetric analyses for determining uranium dioxide non-stoichiometry have been reviewed. Parameters of oxidation in air at various temperatures have been examined. The key parameters affecting accuracy of the obtained results have been evaluated. Oxidation parameters have been proposed, both for pure uranium dioxide as well as for uranium dioxide with added gadolinium oxide, which makes it possible to determine oxygen to metal (O/M) ratio with at least ±0.002 accuracy in weighed sample portions of approximately 3 g.
Radiation effects in coatings ZrTiN induced by impact of high energy krypton ions
Authors: Adabergenova T , Kislitsin S , Uglov V , Ivanov I , Larionov A , Ryskulov A
Published: December 2020

This paper presents research results of the impact of high-energy krypton ions on structure and mechanical properties of ZrTiN coatings. The ZrTiN coatings were synthesized by the magnetron sputtering method on the substrates from Cr18Ni10Ti steel. Samples irradiated by 84Kr14 with energy 125 MeV to fluence 1016 cm−2 at room and 600°C temperatures. It established that irradiation resulted in significant changes in the surface structure, i.e. appearance of the coral-like structure. Formation of coral-like structure leads to degradation of mechanical properties such as hardness and corrosion resistance. Most significant changes surface structure and properties of coating observed after irradiation at room temperature.
Oxidation of boron-titanium thin film coating during cyclic tests on thermal shock
Authors: Suslov E E , Larionov A S , Kislitsin S B , Chernov I I , Staltsov M S , Dikov A S , Firsova V V
Published: December 2020

The results of experiments on cyclic thermal shock tests of promising neutronabsorbing titanium boride coatings are presented. It has been established that the main effect is the high-temperature oxidation of titanium boride with the formation of titanium and boron oxides. The regularities of changes in the oxidation parameters during cyclic thermal shock tests are determined.
Study of Ti-Zr-Nb-Be filler metal interaction with silicon carbide based ceramics during brazing process
Authors: Eroshenko A A , Ivannikov A A , Fedotov I V , Suchkov A N , Dzhumaev P S , Sevryukov O N
Published: December 2020

This work is devoted to an analysis of the composition of a silicon carbide based ceramic brazed seam as a result of its interaction with rapidly quenched titanium-zirconium-niobium-beryllium filler metal. Structural-phase studies based on EDX and EBSD analysis, mechanical shear tests, and microhardness measurements of brazed joints were carried out. It was shown that titanium, zirconium, and niobium silicides as well as particles of titanium carbosilicides and silicon carbides in the silicon matrix are formed in the brazed seam, probably because of the presence of free silicon in the base material, which leads to increasing joint microhardness and unstable shear strength results.
Durability Studies of Solid Pellets from Torrefied Leucaena Leucocephala
Authors: Wei C K , Mohamed A R , Zin A M , Salleh N H M , Aziz A H A , Kasim M Q C
Published: December 2020

Torrefaction of Leucaena Leucocephala was performed in a fixed bed reactor at temperature of 300 °C and 20 minutes holding time under inert environment. The torrefied Leucaena Leucocephala was pelletized with starch as the binder. Two parameters were investigated such as different ratio of starch addition to torrefied Leucaena Leucocephala pellets and the thickness of torrefied Leucaena Leucocephala pellets towards its durability. The ratios of starch addition to torrefied Leucaena Leucocephala pellets studied were 0, 5,10,15,20 and 25 wt%. Meanwhile, the studied thickness of torrefied Leucaena Leucocephala pellets were 0.3, 0.4, 0.5, 0.6 and 0.7 cm. It was observed that when the ratio of starch addition to torrefied Leucaena Leucocephala pellets was varied from 0-25 wt%, the durability increased steadily and the highest durability of 56.06% was achieved at 20 wt%. When the thickness of torrefied Leucaena Leucocephala pellets was increased from 0.3-0.7 cm, the highest durability of 93.18 % was achieved at 0.5 cm thickness. Scanning Electron Microscope (SEM) analysis was performed on the torrefied Leucaena Leucocephala pellets of 0 and 20 wt% ratio of starch addition. SEM images show the existence of some minor pores on the surface of torrefied Leucaena Leucocephala pellet at 250X and 1000X magnifications.
Supercritical Carbon Dioxide Extraction of Malaysian Stingless Bees Propolis: Influence of Extraction Time, Co-modifier and Kinetic Modelling
Authors: Mohd Idrus Nor Faadila , Putra Nicky Rahmana , Yian Lee Nian , Idham Zuhaili , Tee Tan Ah , Soong Cheong Chiew , Aris Noor Aiysah , Md Norodin Nur Salsabila , Che Yunus Mohd Azizi
Published: December 2020

In the present work, the influence of extraction time and co-modifier on the yield of two types of MSB propolis, hard and sticky, using supercritical carbon dioxide extraction technique were evaluated. Different pressure, CO2 flowrate and co-modifier percentage was studied at constant 40°C. SCCO2 extraction was carried out at high (25MPa, 5 ml min−1 CO2, 7% ethanol) and low (15MPa, 3 ml min−1 CO2, 3% ethanol) operating conditions for both hard and sticky MSB propolis. The result shows that 240 minutes was the best and efficient extraction time. Meanwhile, at high operating condition in SCCO2 technique has increased extraction yield of 1.1608g and 0.5656g for both hard and sticky MSB propolis with the addition of co-modifier. Extraction yield without co-modifier addition was 0.3602g and 0.0542g for hard and sticky MSB propolis, respectively. Co-modifier addition to the process had increase the extraction yield as much as 10 folds higher for sticky MSB propolis whilst, 3 folds higher for hard MSB propolis. These findings show that SCCO2 method propose a feasible technique for MSB propolis extraction as it only require short extraction time and complemented with co-modifier application. Brunner and Esquivel model were used to determine the kinetic behaviours in the extraction process. The maximum extraction rate found was 3×10−4 g sec−1 from the fitting the kinetic models.
Methane Gas Production from different composition of Food Waste and Chicken Manure
Authors: Tengku Roslina T Y , Maslinda A B , Mansor N N , Mohd Faiz M S , Hasfalina C M , Nor’Aini A R
Published: December 2020

High carbohydrate content in food waste is one of the characteristic suitable acted as a co-substrate for fermentation to produce methane gas. In this study, co-digestion of chicken manure (CM) and food waste (FW) was used for fermentation process in methane gas production. The different effects of the independent variables (ratio, pH and temperature) is the most significant parameters of methane gas fermentation of CM and FW were investigated. Based on the analytical study showed a good fit between the experimental and the predicted data as the R2 values of 0.991 with methane yield to be 537 mL CH4/g VS at ratio 80:20 (CM:FW); temperature 35 °C; and initial pH 7.11 in 20 days of fermentation. The experiment was then performed based on optimized parameters of pH, temperature and ratio at the highest yield of methane obtained from optimum parameters. After optimization, the result showed that the pH 7.11 at 35 °C temperature and the ratio of 80:20 with methane production yield of 1560.5 mL CH4/g VS for the 21 days of digestion process.
Chloroplast DNA sequence of trnR-N and trnL-F regions in Harumanis mango from different orchards in Perlis, Malaysia
Authors: Rahman AMA , Sabri SFM , Yusuf A , Zakaria Z , Kumar SV
Published: December 2020

Harumanis is a premium mango cultivar widely known for its sweet taste, aroma and vibrant flesh colour. To date, the genetic identification of this mango based on multiple conserved DNA region using samples from different orchards has never been reported. The aim of this research is to identify the genetic signature of Harumanis mango at molecular level by analyzing chloroplast DNA sequences of the trnL-F and trnR-N regions. DNA samples were extracted from a total of 15 Harumanis samples collected from five selected orchards using Cetyl Trimethyl Ammonium Bromide (CTAB) extraction procedure. The extracted DNA and the PCR-amplified products were analyzed through gel electrophoresis and were then subjected to DNA Sequencing and in silico analysis. The obtained sequences were compared with the sequences available in the GeneBank. BLAST search for both the trnR-N and trnL-F regions confirmed that all the 15 samples belong to Mangifera indica with a 99% sequence identity. In addition, the trnL-F sequences were 99% identical to a number of specific mango cultivars such as, Tommy and Arunika. However, the trnR-N sequences were less informative as it gave hits to only two mango accessions (e.g. Mangifera indica voucher PDBK 2014-0249). It is postulated that the plastid trnR-N may be a potential candidate region for the development of the Harumanis genetic signature. The results may be used to complement other molecular data for the development of a genetic barcode for Harumanis.
Mathematical modelling of moisture sorption isotherms by using BET and GAB models
Authors: Abdullah S , Keoh S C , Johar H M , Razak N A , Shaari A R , Rukunudin I H
Published: December 2020

Fish cracker is a popular local fish based snack in Malaysia. Besides the raw form which can be consumed directly, it is always eaten in the dried form. Thus study of moisture sorption isotherm of fish cracker is essential as to predict appropriate drying and storage conditions consecutively to enhance its nutrients, taste and aroma. In this study, the moisture sorption isotherms of fish crackers from two manufacturers M1 and M2 were developed by using a static gravimetric method at temperatures of 30, 40 and 50˚C and water activity (aw) range of 0.04 to 0.80. It is a relationship between equilibrium moisture content (EMC) and aw at a specified temperature. The isotherms exhibited a sigmoid shaped which classified as type II in Brunauer–Emmett–Teller (BET) classification. The increase of temperature decreased the EMC of fish crackers while increase of aw increased the EMC. There was no significant difference of EMC between manufacturers M1 and M2. The moisture sorption isotherms of fish cracker were fitted into predicted isotherms by Guggenheim-Anderson-de Boer (GAB) and BET models. GAB model was found to be the best fit model of fish crackers’ moisture sorption isotherms as compared to BET model.
SURFACE WATER (WETLANDS) QUALITY ASSESSMENT IN COIMBATORE (INDIA) BASED ON NATIONAL SANITATION FOUNDATION WATER QUALITY INDEX (NSF WQI)
Authors: Murali K , Meenakshi M , Uma R N
Published: December 2020

All Water quality index (WQI) is a unique rating to depict the overall water quality status in a single term to address the issues. The present work aims at assessing the water quality in terms of National Sanitation Foundation Water Quality Index [NSF WQI] in the four wetlands namely Ukkadam, Kurichi, Singanallur and Perur in Coimbatore, India. The surface water samples were subjected to compressive physio-chemical analysis. For calculation of NSFWQI nine parameters, DO, FC, BOD, pH, Phosphate, Nitrate, Turbidity, Total Solids and Temperature were considered. It is apparent from NSFWQI values that surface water in Ukkadam wetland falls under bad category. The water quality in Kurichi, Singanallur and Perur belongs to medium category.
Speed and Area Efficient FXP Adders and Multipliers: A Comparative Analysis for LNS System
Authors: Basir M S S M , Ismail R C , Naziri S Z M , Isa M N M , Murad S A Z , Harun A
Published: December 2020

In this paper, a variety of adder and multiplier are compared to be implemented in a new logarithmic number system (LNS). Both adder and multiplier are designed with a generic very high-speed integrated circuit hardware description language (Verilog) program. This makes it possible to achieve the optimum performance in latency and area of 0.18µm CMOS technologies LNS chip. Consequently, the optimal configurations vary with speed and area of the schemes and in some cases can be compact area, O(n), fast in latency O(log2
n) or optimized. The program was scripted based on fixed-point (FXP) adders and multipliers that yet will be implemented in LNS system. The functionality of the scheme was tested before synthesized. Outcomes show that Ladner Fisher (LF) adder and modified Baugh Wooley multiplier contribute to fast in latency and consume minimal area.
Modified ISR hyper-heuristic for tuning automatic genetic clustering chromosome size
Authors: Adnan M H , Hassan M F , Aziz I A , Nurika O , Husain M S
Published: December 2020

Recent works using hyper-heuristics for solving clustering problems have been focusing on Genetic Algorithm. However, to the best of this research knowledge, no work is using hyper-heuristics dedicated for tuning the Genetic algorithm`s chromosome size for automatic clustering problem. The ability to tune the chromosome size is important because it allows the automatic clustering algorithm to be adaptive and dynamic. This paper proposes and evaluates a modified Improvement Selection Rules hyper-heuristic algorithm for tuning automatic genetic clustering chromosome size. The paper reviews related works of Genetic algorithm`s parameters tuning and selective hyper-heuristic algorithms and proposes a modified algorithm. The Iris, Breast Cancer, Wine and E-coli datasets are used for evaluation of the algorithm, based on the fitness, accuracy and robustness. The results indicate that the hyper-heuristic algorithm has produced good performance (fitness) and accuracy but consume considerably higher execution times.
Design A CPW Fed Implantable Antenna at frequency 2.4 GHz for Wireless Implantable Body Area Network
Authors: Ramli N.H. , Othman Hazila , Hamzah Dayang Khadijah
Published: December 2020

Designing implantable antenna is quite challenging due to the effect of lossy environment, necessity of small size and low power consumption and sequence of multipath losses. Thus, compact, small size and better performance are required for an antenna to operate in such systems. In this paper, the implantable antenna is designed by implemented coplanar waveguide (CPW) fed technique to enhances the antenna performances at frequency 2.4 GHz. The antenna performances are evaluated in term of return loss, gain, efficiency, radiation pattern. As the antenna is designed for wireless implantable body area network, hence, the antenna is tested in lossy environment. In this case, the antenna is submerged into a canola oil as it’s dielectric properties represent a human breast fat. The propagation links between antenna inside human body phantom and antenna in free space environment are evaluated. The simulated and measurement results are in good condition. The results of the investigation can be a references in the future.
Idvc Based Hysteresis Controller For Three-Phase Induction Motor Drive
Authors: Sangeetha S. , Mahalakshmi R. , Poornima D.
Published: December 2020

Induction Motor is the most commonly used motor in industrial applications due to its characteristics like self-starting, reliable and easy speed control. The objective of the proposed system is to provide efficient speed control with lesser current harmonics. The Indirect Vector Control (IVDC) method is been presented for speed control of induction motor due to its high dynamic and low drift property. Though there were many classical methods for speed control like Ward-Leonard method etc.; in later years, power electronics circuits were preferred due to its high efficiency, reliability and accuracy. But the presence of static converter in drive circuits results in harmonics, giving in high feedback complexity. Therefore, the Hysteresis controller with conventional Proportional Integral and Differential (PID) control for speed and PI controller for flux is used to control the current harmonics at the point of common coupling. The simulation for speed control in squirrel-cage induction motor is carried out using the MATLAB/Simulink and the parameters like torque, speed, current and Total Harmonic Distortion are analyzed to show optimal response of drive system.
A review of diesel spray research
Authors: Mohd Nawi Mohd Al Hafiz , Mustafa Wan Azani , Shahrol Aman Muhammad Nazrin Shah , Saidi Syahrul Affandi , Mahyudin Ilham Shafini , Jamlos Mohd Aminudin
Published: December 2020

The following literature review provides an overview of research and a summary of the most condition that relevant to the present study. The overview focuses on such parameter such as the effect of ambient condition (density and temperature), the effect of fuel injection, the effect of injection pressure, the effect of mass fuel and effect of nozzle diameter that probably effects into the droplets distribution, sprays evaporation and mixture formation of diesel spray. The preferred format has been choosing to allow an easier scanning and classification which intend to summarize the relevant topic and study regarding the diesel spray fields.
Mechanical properties and environmental assessment of recycled carbon fibre reinforced polypropylene and acrylonitrile butadiene styrene products
Authors: Allawi A N , Shuaib N A , Omar N W Y , Azmi A I
Published: December 2020

In this study, the main objective is to determine effect of recycled carbon fibre (RCF) on the mechanical properties of thermoplastics composites and associated environmental impacts. Such study is important to improve the strength of the composites as previous studies are limited on RCF composites, particularly in environmental aspects. In the compounding stage, extrusion process was carried out by using two different thermoplastics i.e. polypropylene (PP) and acrylonitrile butadience styrene (ABS) mixing with RCF. Particle size and weight loading of RCF were chosen as parameters to be studied. Bonding strength between the RCF and thermoplastics matrix was investigated through tensile and flexural properties. Lastly, the assessment of the products was carried out to determine the environmental impacts. Generally, the incorporation of RCF into PP and ABS plastic increases the tensile and flexural properties of the samples. It can be seen that the addition of rCF significantly improves tensile modulus and flexural strength up to 10 wt% filler loading. From the environmental impact assessment, the ABS products have greater impact in all categories. The usage of rCF reduce the amount of plastic hence leads to lower environmental impacts. The product has a potential to be used in mechanical demanding application particularly those require high flexural strength and tensile modulus properties.
Design and development of driving external support for lower limb disable patients
Authors: Mansor N N , Maslinda A B , Roslina Tg. , Daud Ruslizam
Published: December 2020

The driver who lower limb disabled patients were used the hand control to drive. The hand control was fixed permanently on the pedals. Thus, their family cannot share the car with them. Hence, there are several ways to innovate the hand control become portable product. This study was undertaken to investigate the characteristic driving behaviour of lower limb disabled patient yet to establish the design driving external support that was portable by using hand control. There are many types of mechanism that was used to upgrade the product function compare to existing product. The materials mainly used steel as the materials of hand control stick. The fabrication process was used two weeks to done the prototype. Using a novel upgrading of portable hand control may help the disable patient easily use the fingers and hand, without using any tools. This product also can be refit in others car. The innovation of mechanism assists patients can share their car with their family members.
Mechanical and morphology of interwoven Kenaf/PALF hybrid composites at different fibre ratio
Authors: Maslinda A B , Mansor N N , Tengku Roslina T Y , Majid M S A
Published: December 2020

As the extension to the research involving woven and natural fibre hybrid composites, this study characterise the mechanical properties of natural fibre hybrid composites with different fibre ratio. Plain weaved kenaf/PALF composites with fibre weight ratio of 10/10, 15/15 and 20/20 are fabricated via the hand lay up technique using epoxy as the matrix. Tensile and flexural test are performed according to ASTM D3039 and ASTM D790 standards, respectively. Morphological structure of the fracture specimens were examine using the Scanning Electron Microscope (SEM). As a result, the 15/15 fibre ratio composite had the highest tensile and flexural strength. Addition of kenaf fibre improve the mechanical properties of the composites and increase the potential of PALF fibre as filler for future natural fibre applications.
Therapeutic nano-device: Study of biopolymer coating on titania nanotubes array loaded with chemodrug targeted for localized cancer therapy application
Authors: Wan Eddis Effendy Wan Nuramiera Faznie , Mydin Rabiatul Basria S.M.N , Gazzali Amirah Mohd , Sreekantan Srimala
Published: December 2020

Polymer coating for drug delivery system act as command for drug release rate either for instant, sustained or extended prolonged release dosage. This coating layer also is crucial to protect the functional stability of drug that loaded into delivery platform especially the smart delivery systems. Presently, titania nanotube arrays (TNA) platform have been discussed as nanotherapeutic device for drug delivery system especially in localized cancer therapy application. The purpose of this study is to investigate the outcome of chitosan coating on cisplatin-loaded TNA. Chitosan coating on cisplatin-loaded TNA have shown extended cisplatin release activities until day 28 period compared to the uncoated cisplatin-loaded TNA. Burst release was observed within the first 6-h period for both the chitosan uncoated and coated samples. Spike stable cisplatin release from coated TNA sample was observed after day 20, which suggested polymer coating on TNA platform may provide probable an extended-release cisplatin delivery activity. Findings from this work suggest the potential of TNA as nanotherapeutic device for extended cisplatin release platform in localized cancer therapy application.
Characterization of aluminium / (SiC+B4C) ceramic particles reinforced hybrid Surface Composites (SC) fabricated by friction stir processing
Authors: Varun B , Kumar V Muthu , Jery Rajkumar L , Medhunhashini D.R
Published: December 2020

Friction stir processing (FSP) has advanced as a novel method used for the fabrication of surface composite (SC), refinement of microstructure and enhancing the mechanical properties. In this paper, aluminium surface matrix composite (SMC+ B4C) was fabricated on the surface of aluminium alloy (6082) with ceramic (SiC+B4C) reinforcement using friction stir processing technique. In order to analyse the effect of SiC+B4C particles, its percentage fraction on the microstructure, mechanical and the sliding wear behaviour. A single pass FSP was carried out using a tool with 1000 - 1200 rpm rotational speed, whose travel speed of 45 to 60 mm/min and a vertical force to produce the composite. Aluminium Matrix Composites with different percentile combinations were synthesized. The microstructure of the AA6082/SiC+B4C AMCs was studied using optical and scanning electron microscopy. The micro hardness was measured and the sliding wear behaviour was evaluated using a pin-on-disc apparatus. Thus, the results revealed that the effect of SiC+B4C particles significantly influenced the area of the composite, dispersion, grain size of matrix, micro hardness, and sliding wear behaviour of the AA6082/SiC+B4C AMCs. With this the effect of SiC+B4C particles on fracture surface and worn surface is also reported in this paper.
Experimental investigation of machining parameter on hole quality in drilling Ti-6Al-4V
Authors: Rashid R A , Murad M N , Hamidon R , Shariffuddin S , Ali M A M
Published: December 2020

Titanium alloys (Ti-6Al-4V) are greatly recommended for high performance applications because of their outstanding properties such as low weight, high corrosion resistance and high strength. However, drilling Ti-6Al-4V generates high cutting temperature, especially during high speed drilling (HSD), increased the chemical reactivity of Ti-6Al-4V, thus leading to poor hole quality. High cutting speed increases the temperature during the drilling process, therefore, it is important to consider this factor to achieve better hole quality. This study focuses on the correlation of machining parameter and the quality of the hole produced in terms of hole diameter, roundness and surface roughness. The experiment was conducted using a 6 mm diameter of coated (TiAlN) carbide tool under MQL and MQCL conditions with varying cutting speeds of 65, 75, 85 and 95 m/min and constant 0.02 mm/rev feed rate.