bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on discharge mode and transition mechanism of atmospheric pressure Ar/Zn pulsed microwave plasma jet
Authors: Zhang Sanyang , Chen Zhaoquan , Yang Jie , Chen Sile , Feng Deren , Zhou Yuming , Wang Bing , Lu Xinpei
Published: September 2021

The microwave plasma jet has the advantage of high plasma density and abundant active particles but fails to produce large-scale microwave plasmas in ambient air which hinders the application of microwave plasma ignition and combustion. We have applied a surface wave resonator (including a Zn-coated iron wire trigger) to produce a large-scale Ar/Zn pulsed microwave plasma jet. The discharge experiment shows that the plasma jet generally presents three discharge modes, namely, filamentous argon discharge (P < 120 W), bright argon plasma filaments covered by Ar/Zn thin plasma layers (120 W ≤ P ≤ 150 W), and bright thick Ar/Zn plasma columns (P ≥ 155 W). The optical emission spectrum indicates that the electron temperature is ∼4000–5000 K, the electron density is on the order of 1015 cm−3, and the plasma has the characteristic of local thermodynamic equilibrium. According to the transient discharge photos and the simulated electric fields, the mechanism of the three discharge modes and their transformations could be attributed to the combined interactions (the mutual resonance enhancement between the surface wave and the plasma jet, the propagation of the ionization wave, and the different particle states in the Ar/Zn pulsed microwave plasma). The results have suggested that the large-scale Ar/Zn pulsed microwave plasma jet can be generated by adding Zn vapor into the Ar microwave plasma jet and the proposed Ar/Zn pulsed microwave plasma jet is suitable for the application of plasma ignition and combustion.
A modified reciprocal equation to predict the complex transmission coefficient of a flow duct
Authors: Liu Lianyun , Zheng Xu , Hao Zhiyong , Qiu Yi
Published: September 2021

Reciprocity is a basic property existing in wave phenomena characterized by complex transmission coefficients. Reciprocity in a duct describes the relationship between the direct response at the duct outlet to a source applied at the inlet and the reverse response at the inlet to a source at the outlet. The reciprocity has been adopted to simplify the methodology for predicting the reverse transmission coefficient from the direct coefficient and vice versa. The existing methods, however, cannot predict the complex form of the coefficient because they only consider the reciprocity in the moduli but neglect the reciprocity in the phases. The study on the reciprocity in a duct with a temperature gradient has hardly been seen. The present work derived a reciprocal equation with a time domain method to characterize the reciprocity in a duct with spatially varying temperature. In addition to considering the reciprocity in the moduli of the direct and reverse transmission coefficients, the proposed method invented a correction term to consider the reciprocity in their phases as well. The correction term was developed from the time delay between the incident and the transmitted pulses in the duct solved with the time domain method. The modified reciprocal equation using the correction term was derived and used to predict the reverse transmission coefficient for calculating exhaust noise of an engine connecting to the duct. The result has shown that the proposed time domain method is an effective approach to accurately describe the phase relationship of waves in flow ducts.
Design of a large-radius high impedance intense current diode based on gradient magnetic field
Authors: Chen Yinghao , Ju Jinchuan , Zhou Yunxiao , Zhang Jun , Zhang Wei , Zhang Faning
Published: September 2021

In order to reduce the size of high impedance diodes and magnetic energy consumptions, a high impedance intense current diode is designed in this paper. By reducing the center radius of the cathode and utilizing the gradient magnetic field, the electron beam is emitted in the cathode with a small radius and transmitted in the drift tube with a large radius. The influence of magnetic field distribution on the electron beam transmission is analyzed by particle-in-cell simulation. When the diode voltage is 680 kV, the impedance is 77 Ω, and the cathode radius is 60 mm, the anode radius of the traditional diode is 116 mm and the cathode–anode axial gap is 57 mm. At the same voltage and impedance, the cathode radius of the novel diode is 38 mm, the anode radius is reduced to 80 mm, and the cathode–anode axial gap is shortened to 36 mm. Further application of the novel diode to a relativistic triaxial klystron amplifier device shows that the output power of the novel diode is the same as that of the traditional diode. Through simple quantitative analysis, it is found that the magnetic energy consumption of the novel diode is less than that of the traditional diode. To sum up, the novel diode can achieve good performances in a smaller volume than the traditional diodes.
Improving science education: It’s not rocket science—it’s harder!
Authors: Pompea Stephen M. , Russo Pedro
Published: September 2021

Scientists can help by partnering with museums, out-of-school programs, schools, organizations that develop instructional materials, or other educational projects.
Obligate movements of an active site–linked surface domain control RNA polymerase elongation and pausing via a Phe pocket anchor
Authors: Bao Yu , Landick Robert
Published: September 2021

Significance

RNA synthesis by cellular RNA polymerases depends on an active-site component called the trigger loop that oscillates between an unstructured loop that admits NTP substrates and a helical hairpin that positions the NTP in every round of nucleotide addition. In most bacteria, the trigger loop contains a large, surface-exposed insertion module that occupies different positions in different transcription complexes but whose function during active transcription is unknown. By developing and using a disulfide reporter system, we find the insertion module must also alternate between in and out positions for every nucleotide addition, must swivel to a paused position to support regulation, and in enterobacteria, evolved a “Phe pocket” that captures a key phenylalanine in the out and swivel positions.
Tetrapartite entanglement measures of generalized GHZ state in the noninertial frames
Authors: Dong Qian , Carrillo R. Santana , Sun Guo-Hua , Dong Shi-Hai
Published: September 2021

Using a single-mode approximation, we carry out the entanglement measures, e.g., the negativity and von Neumann entropy when a tetrapartite generalized GHZ state is treated in a noninertial frame, but only uniform acceleration is considered for simplicity. In terms of explicit negativity calculated, we notice that the difference between the algebraic average π
4 and geometric average Π
4 is very small with the increasing accelerated observers and they are totally equal when all four qubits are accelerated simultaneously. The entanglement properties are discussed from one accelerated observer to all four accelerated observers. It is shown that the entanglement still exists even if the acceleration parameter r goes to infinity. It is interesting to discover that all 1-1 tangles are equal to zero, but 1-3 and 2-2 tangles always decrease when the acceleration parameter r increases. We also study the von Neumann entropy and find that it increases with the number of the accelerated observers. In addition, we find that the von Neumann entropy S
ABCDI, S
ABCIDI, S
ABICIDI and S
AIBICIDI always decrease with the controllable angle θ, while the entropies S
3 – 3 non, S
3 – 2 non, S
3 – 1 non and S
3 – 0 non first increase with the angle θ and then decrease with it.
Location of freight warehouses facilities: A GIS-based multi-criteria decision analysis
Authors: Wazer Zaina B , Moutaz Noor
Published: September 2021

Freight transportation is of high importance and is used to determine the region’s economy. Typically, effective freight transportation systems are related to decreasing the costs of moving goods from and to the logistics facilities. The city of Baghdad suffers from many problems with the land transport system, especially the transportation of goods, and among the important things to reduce the current burden on the network is to find the most suitable sites for the establishment of warehouses distributed over each city of Baghdad. Understanding the assembly pattern of the truck’s trip ends can help improve the location of these facilities on space. This paper explores the best places for unloading (warehouses), using 4 criteria that affect taking the most appropriate location for warehouses to improve logistical facilities, which are (land use, population, current warehouses, road network). The weight of criteria was collected from the questionnaire using the Google form and obtain answers from Decision-makers to include them in the AHP hierarchical analysis process to obtain the weights for each criterion. Multi-criteria decision analysis is performed to create a suitable surface to identify potential locations where new logistical facilities can be established. The ArcGIS 10.7 software and its extensions (i.e. spatial analysis and network analysis) are used extensively in analysis for modelling site allocation. The results indicate that the most suitable sites from the group of sites that appeared in the analysis are (near the entrance to the Diyala Bridge and the entrance to the people on the outskirts of the city of Baghdad).
Comparison of the winglet aerodynamic performance in unmanned aerial vehicle at low Reynolds number
Authors: Putro S H S , Pitoyo B J , Pambudiyatno N , Sutardi  , Widodo W A
Published: September 2021

The Aerodynamic performance of an object is very dependent on the flow of fluid through it and the geometric shape of the object. The use of Unmanned Aerial Vehicle (UAV) demands high aerodynamic performance because it strongly supports the cruising range and fuel or battery used. By reducing drag and increasing the lift optimally, the resulting lift to drag ratio will get maximum results. This study compares the use of winglets in UAVs at low Reynolds numbers. This is very important because generally UAVs are used at low Reynolds numbers. The freestream used is Re = 2.34 x 104 on several low to high angle of attack. The type of airfoil used is Eppler 562 which is equipped with a winglet. Winglets used are simple winglets, blended winglets, and wingtip fence. The geometry was analyzed using numerical simulations namely computational fluid dynamic (CFD). The turbulent model used in this study is K-ω SST on Ansys 19.1. From this study it was found that the use of a wingtip fence produced the best aerodynamic performance compared to other configurations. In addition, the use of a wingtip fence can delay stall and separation better than simple and blended winglets.
Structure from Motion (SfM) method to characterize fluvial sedimentology in Way Semaka river in Lampung province, Indonesia
Authors: Wibowo R C , Mulyatno B S , Dewanto O , Sarkowi M
Published: September 2021

Structure from motion (SfM) has been applied recently in fluvial sedimentology. This application is due to the availability of many low-cost unmanned aerial vehicles/drones, which can help overcome challenging terrain, provide efficient and reproducible and high-accuracy topographic images and data. The current study describes the application of SfM to build a geomorphological model and estimate the surface water velocity of the Way Semaka River in the Bandar Negeri Suoh (BNS) region in the West Lampung area. Way Semaka is a river type with an extensive meandering system and stable extension tectonic regime relatively. River morphology approximately 96.62 m width and 4 m depth in straight (relatively) area, whereas in channel area approximately 171.22 m width and 5 m depth. The velocity range between 0.39 – 1.56 m/s based on image analysis proven by current meter measurements onsite with an RMS error of 0.25. Manual geomorphic unit level 2 analysis revealed that 9% of the coverage consisted of basins for the channel’s zone, 35% of the coverage consisted of convexity, 9% consisted of planar features, and 37% of the coverage consisted of the transition zone.
Synthesis and characterization exopolysaccharide from algae Spirulina sp. using technique sol-gel as adsorbent Pb(II) ion
Authors: Kausar R A , Buhani  , Suharso  , Setiawan A
Published: September 2021

In this study, a modification of exopolysaccharide (EPS) from Spirulina sp. algae biomass with silica (HES) and exopolysaccharide from Spirulina sp. algae biomass with silica coated by magnetite particles (HESM) has been done successfully. A series of experiments with the batch method were conducted to test the ability of HESM adsorption of Pb(II) ions in solution. Identification of functional groups of HESM adsorbents was studied using infrared spectrometer (IR) while surface morphological analysis and composition of the constituent elements of HESM were performed using scanning electron microscope-energy (SEM). Concentration of Pb(II) ion in the adsorption process were analysed by inductively coupled plasma-atomic emission spectrometry (ICP-AES Adsorption of Pb(II) ions with HES and HESM is optimum at pH 7 and concentration at 25 ppm with the adsorption capacity on HES at 3.85 mg g−1 while on HESM at 272.63 mg g−1, contact time of 15 min and it tends to follow second orde pseudo kinetic model and Langmuir adsorption isotherm model.
The effects of Ozonation and ultrasonic cavitation on batik wastewater treatment with coagulation-flocculation as pre-treatment
Authors: Siahaan I N J , Saputra A E , Karamah E F
Published: September 2021

The batik industry produces large volumes of wastewater with high organic content. Dyes in batik wastewater are difficult to degrade by biological processes. Therefore, further processing is needed to reduce pollutants before being released into the environment. This study aims to observe the performance of the ultrasonic cavitation, ozonation, and combination of ozonation/ultrasonic cavitation to treat batik wastewater, which was first given a coagulation-flocculation pre-treatment with Polyaluminium Chloride (PAC) coagulants. The variations applied were ultrasonic intensity (20%, 30%, and 60%) and pH of wastewater (4, 7, and 10). In this study, it was found that the combination of the ozonation/ultrasonic cavitation method with a pH of 4 and ultrasonic intensity of 20% produced the best performance, namely COD, TSS, and color (Pt-Co) removal of 77.02%, 95.15%, and 94.88%. The ultrasonic intensity and initial pH of wastewater played an important role in the performance of the treatment process. In the ultrasonic cavitation method with an ultrasonic intensity of 20%, the highest percentage of COD, TSS, and color (Pt-Co) removal was 65.59%, 91.51%, and 93.41%. The ozonation method in acidic conditions (pH 4) produced a better performance with COD, TSS, and color (Pt-Co) removal of 70.51%, 94.35%, and 96.10% for 60 minutes.
The effect of Ozonation on the chemical structure of microplastics
Authors: Fitri A N , Amelia D , Karamah E F
Published: September 2021

Microplastics are not susceptible to microbial degradation, thus often end up in aquatic ecosystem. Moreover, microplastics cause danger to aquatic biota and human. Effective technological solutions to degrade microplastics in wastewater treatment plants are desirable. Biodegradation is one of the most applied techniques, but takes a long time. This study evaluates the ozonation as pre-treatment to transform the chemical structure of polyethylene microplastics into more susceptible to biodegradation. The process was done by using a corona-discharge ozonator and batch reactor, varied pH value (6, 7, 8, 10, 12), ozone flowrate (1, 3, 5 L/min), and contact duration (1, 2, 3 hours). The study was begun by quantification of OH radicals and dissolved ozone, ozonation of microplastics, evaluation of ozonation by gravimetric weight loss including the change of microplastics chemical structure through FT-IR (Fourier Transform Infrared). The results revealed chemical structure changes of polyethylene after ozonation confirmed by the appearance of carbonyl bonds and the loss of weight. The optimum operating condition appeared at pH 12 with 5 L/min ozone flowrate, resulted in 0.0482% weight loss and carbonyl bond intensity reached 104.556% after 3 hours ozonation.
Production of palm shell based activated carbon by two stage phosphoric acid impregnation and physical activation
Authors: Yuliusman  , Afifah T M
Published: September 2021

Activated carbon (AC) as a promising gas adsorbent has been widely used in various applications. One of the raw materials that can be utilized is palm shell waste. Palm shell has great potential in terms of quantity and composition as raw material for AC. Palm shell waste production in Indonesia is classified as high and increasing every year. The high amount of carbon and low ash in the palm shell can produce good porous carbon. In this study, The Palm shell was processed through preparation, carbonization, and activation. After being dried and reduced in size, the palm shell was immersed in phosphoric acid (H3PO4) for 24 hours and continued with carbonization at 350ºC for 30 minutes. Then, it was second chemically activated by H3PO4 with activator mass variations and physically activated by N2 gas at 600ºC for 1 hour. AC with the best characteristics was produced by a mass ratio of 2:1 in the second chemical activation. The iodine number and surface area obtained are 1164 mg/g and 1158 m2/g. Furthermore, Pores have formed perfectly on the surface of carbon and the carbon content of AC has reached 76.9%.
Partial discharge type detection and identification based on its sources
Authors: Putra R W , Sinaga H H , Purwasih N , Permata D , Yuniati Y , Sitorus H B H
Published: September 2021

Partial discharge (PD) is a symptom of initial damage to high voltage equipment insulators which if left for a long period will cause total damage to high voltage equipment. This study aims to detect and identify the type of PD based on the source of its discharge so that it can be useful in terms of monitoring and maintenance of high voltage equipment. In this research, the Hilbert fractal antenna sensor is used in the detection process of surface, cavity, and corona PD with different input voltage variables that successfully produce a total of 600 PD signal data on the oscilloscope. To reduce noise on the PD signal, the denoising process is done by utilizing the sym4 wavelet feature found in the MATLAB software. The denoising process generates new data so that the research data becomes 600 original PD signal data and 600 denoising PD signal data. With a statistical approach, all PD signal data is extracted successfully into the mean, skewness, kurtosis, and standard deviation parameters which are useful as input for the PD type identification process. From each of the PD signal statistical data, 450 data are used in the training data process and 150 data are used in the data testing process. The PD type identification process is performed using a back propagation neural network with a mean square error (MSE) level of 0.01. The identification results show that back propagation neural networks are able to identify PD types based on statistical input accurately. In addition, the denoising process also affects the accuracy of the identification results of the PD type that is 95.33% for the original discharge signal to 97.33% for the denoising signal.
Study of the potential utilization of local Lampung Province resources in development of dental implant bioceramics
Authors: Hendronursito Y , Sukmana I , Risano A Y E
Published: September 2021

The increasing of dental implants needs to be supported by local materials’ development as a form of independence for a nation. With its rich natural resources, Indonesia has the potential to be used as a dental implant material. Dental implant materials can be in bioceramic materials consisting of bioactive, bioresorbable, and bioinert. One of the bioactive materials of concern today is glass-ceramics from basalt rock. Meanwhile, the hydroxyapatite material sourced from limestone is the most widely used bioresorbable type. These materials, basalt, and limestone are very much found in Indonesia, including Lampung Province. However, the use of these two materials as bioceramic materials is still very little. Several methods of treating basalt as glass-ceramics and limestone as Hydroxyapatite are described in this article review. The utilization of local potential as a source of dental implant material will provide support for the independence of a nation in the welfare of its people.
Degradation on mechanical properties of virgin and recycled polylactic acid ageing in aqueous environment
Authors: Budin S , Koay M H , Maideen N C
Published: September 2021

A growing demand in polylactic acid (PLA) has increased in recent years due to the increasing of non-degradable plastic wastes. The recycling of PLA waste is seen to be another permissible solution to conserve the resources. This work aims to study the degradation rate of virgin PLA (VPLA) and recycled PLA (RPLA) in terms of the mechanical properties after ageing in different aqueous environment. The samples were immersed in river water (RW) and seawater (SW) for the duration of 150 days. Tensile strength, transverse rupture strength (TRS), impact energy and hardness properties were investigated as a function of immersed time. The results revealed that the loss in the tensile strength accelerated in river water when compared to seawater. There was at least 50% of tensile strength sacrificed in recycled PLA. The TRS had dropped approximately half from its initial value after ageing in river water and about 30% after ageing in seawater. Besides, a huge decrease ranging around 70-80% from its initial impact energy was identified. However, the reduction in hardness was relatively low. The findings will help to elucidate the degradation process of PLA and the desired effect on the mechanical performance for further application.
Densification and mechanical behaviour of zirconia containing flyash as dopant
Authors: Singh R , Ya’akub S R , Hamid A D A , Ibrahim Z , Ali M Y
Published: September 2021

The densification and mechanical behaviour of tetragonal zirconia doped with up to 2 wt% flyash as dopant were studied. In this work, the dopant was blended with commercial 3 mol% yttria-stabilised zirconia powders by attrition milling. Sintering was accomplished by firing the green bodies at various temperatures ranging from 1250 ºC to 1500 ºC under atmospheric conditions. Sintered bodies were evaluated for bulk density, phase retention, elastic modulus, Vickers hardness and fracture toughness. An improvement in the zirconia properties in terms of bulk density, Vickers hardness and matrix stiffness were evident at low sintering temperatures for samples containing up to 0.5 wt% flyash. In contrast, the fracture toughness and tetragonal phase stability of the zirconia was not influenced by the dopant and sintering temperature. The addition of 1 wt% and 2 wt% flyash, however were not effective in enhancing the properties of the sintered zirconia. This study also found that the addition of flyash as dopant was beneficial in suppressing the low-temperature degradation kinetics of tetragonal zirconia in steam environment.
Grafting the carboxyl groups onto DPNR by seeded emulsion polymerization to enhance the compatibility with silica filler
Authors: Woowong J , Phinyocheep P , Sakdapipanich J
Published: September 2021

The modification of deproteinized natural rubber (DPNR) with maleic anhydride (MAH) was synthesized to enhance the better compatibility between silica filler and natural rubber (NR). The presence of carboxylic acid groups (-COOH) of MAH after hydrolysis in the grafted DPNR with MAH (DP-g-MAH) would directly interact with the hydroxyl groups (-OH) of silica filler, resulting from the formation of the ester bonds due to the esterification reaction. It is leading to form the chemical bonding, which is the significantly strong interaction between DPNR and silica filler. The structural characterization of DP-g-MAH was analyzed by Fourier transform infrared spectrometer (FTIR) and proton nuclear magnetic resonance (1H-NMR), respectively. The % grafting level of MAH approximately highs to 99.37 % with the low gel content approximate 14.45 (wt%). In addition, the DP-g-MAH latex was compounded with silica nanofiller 10 phr by latex compounding method. The morphology of silica filled DP-g-MAH (DP-g-MAH/Si 10) was characterized by field-emission scanning electron microscope (FE-SEM) in order to observe the silica dispersion into the DP-g-MAH rubber. The FE-SEM shows that silica filler could disperse in grafted rubber more than the DPNR. In addition, the crosslink density was investigated to confirm the chemical networks, which could occur from esterification between DP-g-MAH and silica filler.
iAMR: intelligent auto-dispenser mosquito repellent system
Authors: Bakar W A W A , Man M , Hwa L C , Wang L Y
Published: September 2021

Dengue fever has become an increasingly significant health threat worldwide. Currently, due to lack of specific treatment or vaccine against dengue, vector control, which is available in many forms, remains a key strategy for dengue fever prevention. Hence, we introduce an iAMR: Intelligent Auto-Dispenser Mosquito Repellent, an innovative system in line with “Industry 4.0” concept where it includes current trend of automation and data exchange. It also includes cyber-physical systems, the Internet of things, cloud computing and cognitive computing. The iAMR solves the issues of when to spray (by auto-spray using sensor) and long live batteries (with LORAWAN technology). When combined with the mini aerosol (X’MOS), it provides an even more effective mosquito control. This all-in-one system ensures a mosquito-free environment in your home. The iAMR device relies on the microcontroller and sensor in order to operate the intended spraying task. The microcontroller used is an IoT based device called ESP8266 which is a WiFi-embedded microcontroller that utilized standard everyday WiFi band frequency which is at 2.4 GHz. A DC geared motor sensor for dispenser device is used. The main contribution of iAMR is to monitor and track for the mosquito repellant (X’MOS) to be refilled. The implementation shows the iAMR system able to update the level of each X’MOS in iAMR devices which reducing the cost of manual human checking for X’Mos refill.
Effect of 3D-printing parameters on the tensile strength of acrylonitrile butadiene styrene (ABS) polymer
Authors: Ya’akub S R , Ibrahim N , Singh R
Published: September 2021

In this research, the tensile strength behaviour of 3D-printed ABS polymer was studied. In particular, the following printing parameters were investigated i.e. angle orientation of 0°, 30° and 45°, layer thickness of 0.2 mm, 0.3 mm and 0.4 mm, and printing speeds of 60 mm/s, 40 mm/s and 20 mm/s. The samples were subjected to tensile loading in order to determine the stress-strain curve, UTS and the elastic modulus. The results indicated that the speed has no major impact on the strength of the 3D-printed samples. On the other hand, the 0.4 mm layer thickness gave the highest stiffness, whereas the angle orientation of 45° gave the highest tensile strength. However, the combination of 3D parameters that resulted in the overall best results was determined as 0.4 mm layer thickness with an angle orientation of 30°.
Microbial chitosan for the fabrication of piezoelectric thin film
Authors: Hazmi A T , Ahmad F B , Maziati Akmal M H , Ralib A A M
Published: September 2021

Chitin has proven to have a good mechanical and electrical properties to be used in making piezoelectric thin films. However, due to the restriction in solubilizing chitosan in many solvents, there is increasing interest in exploring the used of chitosan in producing thin films. Chitosan, compared to chitin, can be easily solubilized in certain dilute acids. Chitosan that has been extracted from fungal biomass can be used for the fabrication of biomaterial thin films. There are different ways that can be used to fabricate a thin film such as electrospinning, spin-coating, solvent casting and also the hot press technique.
Solar Photovoltaic Power Generation for Distillation Process
Authors: Mowaviq M I , Junaidi A , Putri T W O , Rosanda D
Published: September 2021

Indonesia is an archipelago which is one of the countries with the longest beaches in the world. One of the great potentials of the sea can be used to produce freshwater in coastal areas. One of the processes of converting seawater into freshwater vapor is the distillation process. The freshwater vapor condenses and turns into water. Distillation is carried out by evaporating seawater so that the freshwater is separated from the salt. In this research, the distillation process is assisted by a solar power plant with photovoltaic panels. The hardware design consists of a solar panel, solar charge controller, battery, inverter, pump, electric heater, temperature sensor, and level sensor. The solar panel uses a total of 1200Wp with a voltage of 12 V. The battery uses a 12V 100Ah battery and a 1000W electric heater. Meanwhile, the pump power is 48W. From the test results, it was found that in one hour, 1.3 liters of freshwater were obtained with a total capacity of 10 liters of water. The use of solar photovoltaic in a distillation system would be better if combined with direct solar energy heating methods.
Flow drags across three minibus car models arranged in tandem in four configurations
Authors: Salam N , Tarakka R , Jalaluddin  , Ihsan M , Jimran M A
Published: September 2021

The purpose of this study was to investigate the drag coefficient of flow on three tandem minibuses in four configurations and to determine the optimum drag coefficient across the three cars. Flow drags measurements have been conducted on a wind tunnel by force balance measurement. The minibus car models with a 1:40 ratio to the originals were constructed from iron material with a thickness of 1 mm. The three minibus cars are arranged in four configuration models where car 1 and car 2 are arranged in series while car 3 position changeable according to the configuration. Each configuration model was treated with 6 changes in the distance of the car to 3, while the distance between car 1 and 2 was constant, with similar 7 levels of treatment of velocities ranging from 8 m/s to 20 m/s. Results show a similar drag coefficient (Cd) pattern in all configuration models, where smaller Cd related to greater velocities and smaller distances of the three cars. Furthermore, at a similar Re = 49,608, the smallest Cd was obtained in model III (Cd = 0.78), and followed by model II (Cd = 0.80), model IV (Cd = 0.81) and model I (Cd = 0.84).
Maneuverability analysis on flying vehicle with thrust vectoring system
Authors: Al Aviev V H , Sasongko R A
Published: September 2021

Fighter aircraft often require unconventional maneuverability that civil aircraft cannot perform. The conventional flight control devices are not sufficient for this maneuver. Thus, to be able to perform unconventional maneuvers, additional control devices may be required, such as the thrust vectoring system (TVS). This paper will discuss the effect of TVS implementation in improving maneuverability. In this work, a dynamic model of F-4 Phantom is used as the basis for the study. The dynamic model of the aircraft with TVS is constructed analytically and numerically. The nonlinear model obtained from the modeling process then linearized at a particular flight condition and some TVS deflection values. Further, the linear system and control approach is employed for evaluating and designing the linear controllers for stabilization and maneuvering tasks. The closed-loop system, which is implemented in the MATLAB/Simulink environment, then numerically simulated and observed for analyzing the effect of implementing different TVS deflection on the required control effort in high angle of attack maneuvers. The simulation results show that the TVS can affect the performance of the closed-loop system in stabilization tasks. While at some deflection values, TVS can also help to reduce the required control effort to tracking attitude reference command when executing the high angle of attack maneuvers.
Missile threat assessment system using Naive Bayes classifier approach
Authors: Dewangga W , Sasongko R A
Published: September 2021

In the modern era, missiles have been used to serve both defence and offense purposes. Numerous research projects have been conducted to improve various aspects of missile systems. One area of main interest regarding the development of missiles in general is automation, particularly surrounding a feature known as guidance system. This feature had been proven to relieve a missile user of several workloads, particularly during aim and launch phase. One key component of a guidance system is known as threat assessment system. Such system is assigned to assess the threat situation that a missile’s engaged in. In this research paper, the developed guidance system uses an approach that is based on the naive Bayes classifier concept. The idea is to establish a system that first describes relationship between a missile and its’ target during mission in the form of a set of combat parameters. These combat parameters are then treated as evidence that is used by the Bayesian algorithm to update an assigned prior belief, yielding an updated posterior belief. The belief comes in a form of probability distribution with each probability representing a predefined threat situation class.
Essential characterization of metal powder for additive manufacturing
Authors: Ramli S M Q M , Fadzil N A , Ghazali H , Viklund P , Ali W F F W
Published: September 2021

The aerospace industry is mostly focused on complex, low production volume as the components are often known with complicated internal geometries and dimensions. Heavy market competitions and restrictions in high manufacturing cost could be overcome with additive manufacturing (AM). AM has received notable attention in its ability to produce customized metal parts and exhibiting top-notch capabilities that would lead the AM industry in the future. Nonetheless, in producing trusted, high-quality products, characteristics of metal powders should be accounted so it would meet proper quality such as powder morphology, particle size distribution, porosity, and powder’s ability to flow. SEM, OM, laser diffraction and rheometer are suggested in studying the powder’s characteristics. All characterization methods found are used practically. These characteristics are important to assess AM quality. Comparison in different aerospace materials is studied to get the actual material combination in getting an optimum metallurgical bond between the substrate and molten pool of the powders. Therefore, characterization methods of 3D metal additive and characteristics of aerospace materials are evaluated and presented systematically.
Comparison analysis of abaca fiber/polyester and abaca-e-glass/polyester hybrid composites to impact strength and its application to ballistic
Authors: Banowati L , Sari P , Hadi B K
Published: September 2021

The aim of this study consentrates of mechanical properties of abaca fiber and compares with the hybrid fiber composite on using abaca-e-glass fiber as reinforcement for composites. The fibers were arranged to make a bidirectional ±45º fiber arrangements by using polyester as a matrix with hand lay-up method is used to manufacture the composite. Based on the impact test results showed that the abaca-E-glass/polyester has a higher strength than the abaca/polyester specimen. Therefore, the abaca-E-glass/polyester hybrid composite has a better ability to ballistic test.
Short review on heteropoly acid based catalyst for valorization of biomass waste into valueable chemicals
Authors: Adil N L Z Z , Saharuddin T S T , Ozair L N , Harun F W
Published: September 2021

Depletion of fossil fuels resources has triggered more research on finding potential alternative sources that are more sustainable such as biomass waste. However, deconstruction of the complex biomass waste into desired products is too challenging and usually require a strong catalyst with a great hydrolysing property. Common acids such as sulphuric acid, hydrochloric acid and nitric acid were the most studies for biomass conversion. These liquid acids catalysts suffer low recovery and recyclability that can be overcome by a solid acid catalyst. Heteropoly acid (HPA) catalyst is the preferred choice to replace these common acid catalysts as it is known to have a strong Bronsted acid site with an oxidizing property that allows this catalyst to hydrolyse and oxidize in one-step reaction. Furthermore, heteropoly acid (HPA) catalyst can be modified into heterogenous type of catalyst by solidifying HPA to increase the surface area and recyclability. Future work of this research is necessary to improvise the previous method of the catalyst preparation and to suppress the by-products after the catalytic process. In this review, we summarize the use of HPA catalyst in the complex reaction process of biomass conversion to valuable chemical products.
Nonlinear equations of fourth-order with 𝑝-Laplacian like operators: Oscillation, methods and applications
Authors: Bazighifan Omar , Ragusa Maria Alessandra
Published: September 2021

Fourth-order differential equations appear in physical applications (such as fluid dynamics, electromagnetism, quantum mechanics). The aim of this work is to study oscillatory behavior of solutions for a fourth-order neutral nonlinear differential equation, driven by app-Laplace differential operator. Some oscillation criteria for the understudy equation have been obtained by the theory of comparison. The obtained results improved the well-known oscillation results presented in the literature. An example is illustrated to show the applicability of the obtained results.
Convolution properties of Orlicz spaces on hypergroups
Authors: Bagheri Salec Ali Reza , Kumar Vishvesh , Tabatabaie Seyyed Mohammad
Published: September 2021

In this paper, for a locally compact commutative hypergroup

K
K

and for a pair

(

Φ
1

,

Φ
2

)

(\Phi _1, \Phi _2)

of Young functions satisfying sequence condition, we give a necessary condition in terms of aperiodic elements of the center of

K
,

K,

for the convolution

f
∗
g

f\ast g

to exist a.e., where

f
f

and

g
g

are arbitrary elements of Orlicz spaces

L

Φ
1

(
K
)

L^{\Phi _1}(K)

and

L

Φ
2

(
K
)

L^{\Phi _2}(K)

, respectively. As an application, we present some equivalent conditions for compactness of a compactly generated locally compact abelian group. Moreover, we also characterize compact convolution operators from

L
w
1

(
K
)

L^1_w(K)

into

L
w
Φ

(
K
)

L^\Phi _w(K)

for a weight

w
w

on a locally compact hypergroup

K
K

.
FlexTaxD: flexible modification of taxonomy databases for improved sequence classification
Authors: Sundell David , Öhrman Caroline , Svensson Daniel , Karlsson Edvin , Brindefalk Björn , Myrtennäs Kerstin , Ahlinder Jon , Antwerpen Markus H , Walter Mathias C , Forsman Mats , Stenberg Per , Sjödin Andreas
Published: September 2021

The Flexible Taxonomy Database framework provides a method for modification and merging official and custom taxonomic databases to create improved databases. Using such databases will increase accuracy and precision of existing methods to classify sequence reads.

Availability and implementation

Source code is freely available at https://github.com/FOI-Bioinformatics/flextaxd and installable through Bioconda.
Single-cell RNA sequencing analysis of mouse follicular somatic cells
Authors: Li Sen , Chen Lei-Ning , Zhu Hai-Jing , Feng Xie , Xie Feng-Yun , Luo Shi-Ming , Ou Xiang-Hong , Ma Jun-Yu
Published: September 2021

Within the development of ovarian follicle, in addition to cell proliferation and differentiation, sophisticated cell–cell cross talks are established among follicular somatic cells such as granulosa cells (GCs) and theca cells. To systematically reveal the cell differentiation and signal transductions in follicular somatic cells, we collected the mouse follicular somatic cells from secondary to ovulatory stage, and analyzed the single cell transcriptomes. Having data filtered and screened, we found 6883 high variable genes in 4888 single cells. Then follicular somatic cells were clustered into 26 cell clusters, including 18 GC clusters, 4 theca endocrine cell (TEC) clusters, and 4 other somatic cell clusters, which include immune cells and Acta2 positive theca externa cells. From our data, we found there was metabolic reprogramming happened during GC differentiation. We also found both Cyp19a1 and Cyp11a1 could be expressed in TECs. We analyzed the expression patterns of genes associated with cell–cell interactions such as steroid hormone receptor genes, insulin signaling genes, and cytokine/transformation growth factor beta associated genes in all cell clusters. Lastly, we clustered the highly variable genes into 300 gene clusters, which could be used to search new genes involved in follicle development. These transcriptomes of follicular somatic cells provide us potential clues to reveal how mammals regulating follicle development and could help us find targets to improve oocyte quality for women with low fertility.
Changes in histology, protein expression, and autophagy in dairy goat testes during nonbreeding season
Authors: Xi Huaming , Ren Fa , Li Yu , Du Yeqing , Wang Liqiang , Hu Jianhong
Published: September 2021

Seasonal reproduction contributes to increased chances of offspring survival in some animals. Dairy goats are seasonal breeding mammals. In this study, adult male Guanzhong dairy goats (10–12 months old) were used. Testis size, semen quality, hormone level, apoptosis of germ cells, and autophagy of Sertoli cells were analyzed in dairy goats during the breeding (October) and nonbreeding (April) seasons. We found that, during the nonbreeding season for dairy goats, semen quality, follicle-stimulating hormone (FSH) levels, and testosterone levels were reduced, and the number of apoptotic germ cells increased. The proliferation with decrease activity of germ cells in dairy goat during the nonbreeding season was significantly affected. However, the testis size did not change seasonally. Interestingly, Sertoli cell autophagy was more active during the nonbreeding season. The expression levels of FSH receptor, wilms tumor 1, androgen binding protein, glial cell derived neurotrophic factor, and stem cell factor decreased in dairy goats during the nonbreeding season. In summary, our results indicate that spermatogenesis in dairy goats during the nonbreeding season was not completely arrested. In addition, germ cell apoptosis and the morphology of Sertoli cells considerably changed in dairy goats during the nonbreeding season. Sertoli cell autophagy is involved in the seasonal regulation of spermatogenesis in dairy goats. These findings provide key insights into the fertility and spermatogenesis of seasonal breeding animals.
Bioelectrical signal associated with sweet taste transduction in humans is a hyperpolarizing potential on the lingual epithelium
Authors: Fukuda Satoshi , Murabe Naoyuki , Mizuta Haruno , Yamamoto Takashi , Nagai Takatoshi
Published: September 2021

The lingual surface potential (LSP), which hyperpolarizes in response to salt and bitter stimuli, is thought to be a bioelectrical signal associated with taste transduction in humans. In contrast, a recent study reported sweet and sour stimuli to evoke a depolarization of the LSP. We questioned the origin of such a depolarization because liquid junction potentials (JPs), which arise at the interfaces of recording electrode and taste solutions, are neglected in the report. We recorded the LSPs to sucrose and NaCl solutions on the human tongue using an Ag/AgCl electrode. To estimate JPs generated by each taste solution, we made an agar model to simulate the human tongue. The lingual surface was rinsed with a 10 mM NaCl solution that mimics the sodium content of the lingual fluid. In the human tongue, sucrose dissolved in distilled water evoked a depolarizing LSP that could be attributed to JPs, resulting from the change in electrolyte concentration of the taste solution. Sucrose dissolved in 10 mM NaCl solution evoked a hyperpolarizing LSP which became more negative in a concentration-dependent manner (300–1500 mM). Lactisole (3.75 mM), an inhibitor of sweet taste, significantly reduced the LSPs and decreased perceived intensity of sweetness by human subjects. The negative JPs generated by 100 mM NaCl in the agar model were not different from the LSPs to 100 mM NaCl. When the electrolyte environment on the lingual surface is controlled for JPs, the bioelectrical signal associated with sweet taste transduction is a hyperpolarizing potential.
Palliative Care in Inflammatory Bowel Disease: A New Partnership
Authors: Rivet Emily B , Bohl Jaime L , Al Yassin Sarmed , Bickston Stephen J
Published: September 2021

Background

Palliative care (PC) is being increasingly recognized for benefitting patients with a wide spectrum of chronic serious medical conditions.

Methods

Care models and principles of PC for patient with inflammatory bowel disease were explored.

Results

The use of a structured and systematic approach for emotionally laden conversations and the “Total Pain” paradigm are examples of PC expertise that can be applied through either primary or consultative PC models.

Conclusions

PC should be considered in clinical practice and as a topic for further scholarly investigation to further define its role and benefits.
Coevolution between Himalayan cuckoos and 2 sympatric Pycnonotidae hosts
Authors: Yang Canchao , Li Qihong , Su Tongping , Møller Anders Pape , Liang Wei
Published: September 2021

Selection due to cuckoo parasitism is responsible for the evolution of anti-parasitism defenses in hosts. Different host species breeding sympatrically with a single parasitic cuckoo may evolve different strategies to reduce the risk of counter cuckoo parasitism, resulting in different interactions between cuckoos and hosts in areas of sympatry. Here, we studied the coevolutionary interactions between Himalayan cuckoos Cuculus saturatus and 2 sympatric and closely related potential hosts belonging to the family Pycnonotidae, the brown-breasted bulbul Pycnonotus xanthorrhous and the collared finchbill Spizixos semitorques. We investigated parasitism rates and nest-site selection (nest height, nest cover, human disturbance, perch height, forest distance, and degree of concealment) related to parasitism risk, nest defense against a cuckoo dummy, and egg rejection against cuckoo model eggs. Bulbuls used specific nest sites that were further away from forests than those of finchbills, and they behaved more aggressively toward cuckoos than finchbills. In contrast, bulbuls possessed moderate egg rejection ability, whereas the finchbill rejected 100% of cuckoo model eggs. We suggest that selection of a nest site away from forests by the bulbul explains the absence of parasitism by Himalayan cuckoos. We suggest that these interspecific differences in nest-site selection and nest defense indicate alternative responses to selection due to cuckoos.