bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical modelling of freestream cavitating flow through ship propeller using OpenFOAM
Authors: Ngoc Truong Van , Luan Mai Ngoc , Hieu Ngo Khanh
Published: March 2021

In marine industry, cavitation has been a massive problem when dealing with ship propeller. One of the main effects caused by cavitation is thrust breakdown, which decreases the efficiency of propeller. It is difficult to completely avoid this phenomenon, but there are ways to reduce its occurrence. It is important to study the phenomenon in the process of designing propeller. For that reason, cavitation prediction on certain geometry is compulsory to give out the optimal ship propeller design. In this paper, the cavitation analysis on propeller VP1304 was conducted numerically utilizing OpenFOAM code. The motion of the propeller was represented by Arbitrary Mesh Interface (AMI) methodology with the aid of RANS turbulence models. The authors examined the differences between k-ε model and k-ω SST model in this case with the involvement of Schnerr-Saur, Merkle and Kunz cavitation model. The results achieved shows that the k-ω SST model performed more accurately in term of propeller thrust, torque and efficiency prediction. Furthermore, among the three employed cavitation models, Schnerr-Saur agrees best with empirical data, and hence, can be considered most suited for this analysis.
The effect of the inlet temperature of the heat transfer fluid in a rectangular latent heat energy storage
Authors: Naing Than Tun , Mon Mi Sandar , Twe Sai Kham
Published: March 2021

Solar energy is available during the day only. The excess heat energy collected during sunshine hours can be stored in the thermal energy storage and it can be reused during off sunshine hours. Latent heat energy storage systems by using phase change materials (PCMs) can be used effectively for storing thermal energy. It has high-energy storage density and the constant temperature storage process. In this paper, the performance of the latent heat storage system and phase change characteristics of PCM inside a rectangular latent heat energy storage unit will be presented. In this study, purified water is used heat transfer fluid (HTF) which is passed through the copper tubes inside the test unit and commercial-grade paraffin wax is used as PCM and indirect contact heat transfer method is used to heat exchange from the HTF to PCM. It was found that the PCM at the upper layer of the test section first melted during the melting process. Moreover, the effects of inlet temperature of HTF on the charging process was investigated. It can be concluded that increasing the inlet temperature of HTF effectively decreases the total charging time of the melting process. The amounts of heat storage for the inlet temperature of HTF 70 °C and 80 °C are 7400 kJ and 6555 kJ respectively during the melting process.
Wind tunnel experiments on smoke diffusion from a chimney
Authors: Inthavideth X , Nobumasa S , Phommachanh S
Published: March 2021

The diffusion of heated and unheated jets from a chimney was investigated in cross flows with large-scale turbulence generated by a Makita-type active turbulence generator and with gird generated turbulence. The behavior of jet with smoke was observed by a high-speed camera. The smoke was dispersed more widely by meandering motion in the large-scale turbulence. The turbulent eddies corresponding to the integral scale should effectively contribute to the meandering smoke diffusion. The time-averaged smoke concentration distribution was obtained from the brightness values of instantaneous images. The stream-wise variations of the smoke diffusion width and the smoke flow center were evaluated from the distribution. Obtained data were compared with previous correlations.
Bamboo culm vertical lever flattening mechanism with sodium bicarbonate softening process
Authors: Atienza A H , Alba A , Respicio D A , Baratang M A
Published: March 2021

Some constructions require flattening bamboo culms to be used for constructing flat surfaces. With such need for flattened bamboo culms, the aim of this research is to develop a cost-effective and novel way of flattening bamboo culms for the species, Schizostachyum lumampao or buho, by integrating a softening process using sodium bicarbonate water solution and application of steam, then be pressed by a pressing mechanism using counter-bending technique to eliminate spring back effect of the bamboo culm. An open vessel was filled with sodium bicarbonate and water solution tested at concentrations between 15% and 26% by volume and then heated by 1.5 kW immersion heater. Pressure vessel partially filled with water and a 3-kW immersion heater were used to generate steam for the bamboo culm to maintain its flexibility as it is pressed. The bamboo culms reached a mean degree of flatness of 0.91. Thinner “Buho” (bamboo culm) submerged at around 20% of NaHCO3 concentration was successfully flattened within an average flattening time of ten (10) minutes, similar with thicker bamboo culm but submerged at concentration greater than 20% of NaHCO3. The machine had been incorporated with batch-type process and showed an efficiency of 90.75%.
CFD investigation of a combined biomass furnace and solar drying system for paver blocks
Authors: Atienza A H , Adorador L A , Hernandez J A , Vinagrera F J
Published: March 2021

Paver blocks have been widely used as concrete materials for exterior flooring. The process of producing paver blocks consumes a lot of time as the drying period takes at least eleven days. This paper had aimed to design a drying mechanism, a combined biomass furnace and solar collector drying system for paver blocks. and simulate the flow of the system through computational fluid dynamic analysis using SolidWorks Flow Simulation (SWFS) 2018. Desired results had been achieved as temperature, pressure, and velocity fields generated by simulation were accounted to observe fluid distribution in the drying system using contour plots. The temperature in the chamber had increased and uniformly distributed as the heat inputs from the two heat sources converged in the drying chamber. It was observed that the pressure varied from 101,331.72 Pa to 101,327.83 Pa with the highest temperature peaking at 600K and velocity was 1.5 m/s. The theoretical heat produced in the solar collector, biomass furnace and combine system were 191.70 W, 1290.66 W and 1482.36 W, respectively.
Classifying maturity of cherry tomatoes using Deep Transfer Learning techniques
Authors: Huynh Danh Phuoc , Vo My Van , Dang Nghin Van , Truong Tri Quoc
Published: March 2021

This research studies a method to classify the tomatoes’ maturity by using deep transfer learning techniques. We carry out sorting systems adopting three pre-trained convolutional neural networks of VGG16, VGG19, and ResNet101. The experimental results show that the VGG19 model obtains a high precision on both the train set and the test set.
Decision tree analysis of commuter mode choice in Baguio City, Philippines
Authors: Gue I H V , Soliman J , De Guzman M , Cabredo R , Fillone A , Lopez N S , Biona J B M
Published: March 2021

Transportation is a multidisciplinary system. Solving its issues would require the knowledge of social, economic, engineering, environmental, and technological disciplines. Emerging techniques used in problem-solving involve the use of machine learning techniques. In this study, a machine learning technique, decision tree, is used for mode choice analysis in Baguio City, Philippines. Using data from a household survey, the developed model uncovers the most significant factors affecting mode choice of residents in the city. The results highlight the role of income, which is related to the individuals’ career level and stage in life. Interestingly, a mid-level income group seems to be highly inclined towards private vehicle use. To conclude, the authors note that the primary advantage of a decision tree is its simplicity and straightforward results interpretation, which is paramount in policymaking. For future work, the authors recommend exploring larger decision tree models for mode choice and conducting a validation interview of the insights obtained from the study.
Design, fabrication and testing of a portable gravity generator as a back-up power source.
Authors: Agustin R. , Alonzo C , Ami K , Brual J M , Viray D N , Maglaya A , Fernando A
Published: March 2021

In this study a prototype small scale gravity driven generator was designed, tested, and evaluated. The prototype was designed using readily available components. It uses a chain sprocket system and a 24V DC generator. This study might help the needs for a new sustainable energy source, a gravity driven device that harness energy from a falling mass might provide an alternative solution for an increasing energy demand and supply electricity to remote areas.
Fuzzy-based automated nutrient solution control for a hydroponic tower system
Authors: Dela Vega J A , Gonzaga J A , Gan Lim L A
Published: March 2021

Hydroponic farming is gaining significant interests in the field of agriculture due to its many advantages. Its design is modular thereby allowing it to be installed in limited spaces and urban applications. Also, the trend of controlled environment agriculture (CEA) is now prevalent in the study of hydroponics. This ensures that hydroponic setups are invulnerable to plant diseases, infestations, and variable weather systems. One of the challenges in its operation, however, is in the efficient and accurate maintenance of the nutrient solution. Sudden changes in the growth parameters such as ambient temperature, relative humidity, electrical conductivity (EC), and pH level negatively impact the growth of hydroponic plants. Several studies have proposed systems which can control the distribution of the nutrient solution and maintain the optimal levels of growth parameters. This paper discusses a proposed control framework for nutrient solution management in a hydroponic system. Moreover, this system is based on fuzzy logic and designed for the adjustment of the pH level and electrical conductivity (EC) of the mixture. Additionally, the complexities in the process and maintenance of the system were made simple to facilitate easy adaptation and familiarization that even non-educated growers can easily acclimate to the proposed system. Also, dedicated sensor modules were used for monitoring the growth environment. Four treatment solutions were administered using dosing pumps to correct parameter values that went beyond the desired setpoint ranges. This system is applied on a nutrient film technique (NFT) hydroponic tower farm to assess its performance on an actual physical setting.
Numerical analysis on the influence of process parameters on the deep drawn product by using Taguchi method
Authors: Win Nay Chi Than , Myint Phyo Wai , Nandar Wutyee
Published: March 2021

Deep drawing is a metal forming process that involves complex metal flow and widely used in various manufacturing. The process parameters such as punch corner radius and die corner radius affect the product quality. The punch velocity is also important to obtain the desired product shape. However, it is rare to observe the combination of process parameters effects such as punch and di corner radii and punch speed. In this study, the influences of punch corner radius, die corner radius, and punch speed on deep drawn formability and defect formation are analysed. Taguchi Method is applied to build the design of simulations, and the axisymmetric model is used to simulate with Finite Element Analysis-based ABAQUS software. The results showed that the punch corner radius and die corner radius mainly affect stress and strain distribution and the punch velocity affect the formability of the product and the production time.
Plant growth chamber with integrated air conditioning system, periodic irrigation, and adjustable photosynthetic light wavelength
Authors: Atienza A H , Cervantes R T , Dionisio J A , Tan T A
Published: March 2021

The increase in the average temperature due to climate change affects the crop yield production and it can lead to food insecurity. Rapid breeding helps increase crop yield production and improve the overall crop quality. The researchers designed a plant growth chamber with integrated air conditioning system, periodic irrigation, and adjustable photosynthetic light wavelength. The growth rate of the representative plant, green span lettuce, grown in the plant growth chamber is compared to conventional planting. Factors such as growth period rate, dry weight, and overall produce quality are considered. It was found that implementing a 24-hour photoperiod, drip irrigating 50 mL per plant every 2 days, adding vermicast to the cocopeat at a ratio of 1:1 and maintaining a temperature range of 20 to 25 degrees Celsius produced a higher relative growth rate. In consideration of additive nutrients, the addition of vermicast added a substantial increase in the relative growth rate. Quality was also improved due to the correlation of the relative growth rate and plant quality.
Gravimetric and data analysis of the corrosion resistance behaviour and inhibition of C26000 brass in dilute HNO3solution
Authors: Loto Roland T. , Loto Cleophas , Ohwofasa Oshogbunu
Published: March 2021

The corrosion resistance of as-received and heat treated C26000 brass (annealed and quenched) was evaluated by gravimetric analysis in 0.5 M, 1 M, 1.5 M, 2 M, 2.5 M, 3 M and 3.5 M HNO3solution. Generally, corrosion rate of C26000 increased with increase in HNO3concentration and varies significantly with respect to observation time. Results showed that heat treatment has no influence on the corrosion resistance of the brass heat treated brass compared to the as-received sample. Application of garlic extracts in HNO3solution at 0.5 M significantly decreased the corrosion rate of C26000 60% concentration with inhibition value of 79.46%. The garlic extract exhibited significant concentration dependent behaviour and its inhibition performance varies with observation time. Statistical evaluation showed the standard deviation values of as-received and heat treated C26000 varied with respect to mean inhibition data. However, variation increased with HNO3concentration due to thermodynamic instability with respect to observation time. In the presence of the garlic extracts, the high standard deviation values at the lowest and highest garlic concentration signify significant variation with observation time and thermodynamic instability. Evaluation through analysis of variance shows HNO3concentration and observation are statistically irrelevant to the corrosion rate output of as-received and heat treated C26000. In the presence of garlic extracts only the extract concentration is statistically relevant with value of 90.52%.
Seismic Analysis of Concrete Arch Dam Considering Material Failure Criterion
Authors: Baghban Mohammad Hajmohammadian , Faridmehr Iman , Goldaran Reza , Amoly Roozbeh Safaeian
Published: March 2021

Since large dams collapse can lead to catastrophic consequences on human’s lives and properties, the reliable performance of such structures during a strong earthquake is extremely important. Therefore, applying reliable analysis methods for designing large dams and seismic evaluation of the existing dam is crucial. The present study investigates the behavior of a concrete arch dam during the maximum credible earthquake “MCL” through non-linear time history analysis. A 30-meter height concrete arch dam was simulated in SAP2000-academic version- using 3D solid elements. Rayleigh damping and plasticity-based five-parameter Willam-Warnke model, as a means of failure criterion, were taken into account during non-linear time history analysis. The results indicated that the seismic load combination had a significant impact on final stress distribution in which high tensile cracks penetrated over the upstream heel.
Erbium Related Photoluminescence of Silicon: Influence of Co-doping with Oxygen and Hydrogenation
Authors: Islam Aynul , Aynul Anika Tasnim
Published: March 2021

This experiment deals with the influence of co-doping with oxygen and hydrogen and also annealing parameters, temperature and excitation power on the Er related photoluminescence (PL) of silicon. The ultimate goal is to optimise the PL intensity of the Er3+ internal transition to make at room-temperature luminescence possible. Silicon is a very inefficient light emitter, because of the low radiative recombination rate due to the indirect band gap. However, by adding optically active impurities such as erbium, Si can be made luminescent. Silicon is an ideal material for the fabrication of optical waveguides that are compatible with optical telecommunication technology at 1.54µm, because of its high transparency and high refractive index at this wavelength. Co-doping with oxygen and hydrogen can enhance the initial Er luminescence. To investigate the influence of oxygen and hydrogen on the diffusion process and the luminescence intensity, samples were doped with erbium, oxygen and hydrogen at different concentrations that were implanted both on Float Zone (FZ) and Czochralski (CZ) silicon wafers. In FZ silicon, the samples implanted with both oxygen and hydrogen showed the highest luminescence yield with a six times higher peak intensity as compared to samples implanted with only erbium and a two times higher peak intensity as compared to samples with erbium and oxygen, in accordance with previous results. However, identified by the line position and contrary to previous results on CZ-Si, the luminescence stems from an erbium-oxygen impurity complex and not from the so-called cubic centre. In CZ samples doped with erbium, oxygen and hydrogen show a 3 times higher intensity as compared to samples doped only with erbium and oxygen. Although the PL lines of the cubic centre are visible, they do not exhibit the strongest luminescence. In samples doped only with erbium and hydrogen and annealed at 900°C, we observe luminescence from only the cubic centre. Although the appearance of the cubic centre in these samples is most likely due to out-diffusion of erbium in the absence of oxygen, hydrogen again enhances the luminescence intensity by a factor 2.
The Effects of Sintering Additives on the Sintering of 3Y-TZP Ceramic
Authors: Theenagaran S , Ting C H , Chin K L , Yeo W H , Ng C K , Ramesh S , Teng W D
Published: March 2021

The influence of 0.5 wt.% of manganese oxide (MnO2) addition as dopant into 3 mol% yttria stabilized tetragonal zirconia polycrystals (3Y-TZP) were studied in comparison to undoped 3Y-TZP using different sintering profiles. Samples were sintered at 1200°C, 1300°C and 1400°C with holding time of 1 min, 12 min, 2 hours and 20 hours all for single step sintering. The optimal sintering profiles are A4 and C2 where 3Y-TZP doped with 0.5% wt. MnO2 sintered at 1400°C for 12 minutes and 1200 °C for 20 hours respectively. At these sintering parameters, the MnO2 doped 3Y-TZP sample exhibited relative density of ~97%, Vicker’s Hardness value of ~13 GPa, Fracture toughness value of ~4 MPam1/2 and Young’s modulus of ~210 GPa.
The Study on penetration variation of nickel ion in wastewater by laser light technology
Authors: Lin Dan , Xie Fang , Wu Xin-Da , Zhou Hao-Lin
Published: March 2021

The rapid development of industry in the world has brought serious negative effects, so pollution control and prevention is an important issue for the future environment. The discharge and treatment of metal ions in water environment are becoming more and more serious. Common heavy metal analysis methods need the support of large-scale instruments. In the study, the differently control of wavelength, temperature and concentration. Explore theoretical analysis solutions based on laser absorption and scattering, Design of metal ion analysis of laser light penetration. The influence of medium change of metal ions on the light dispersion path is measured by direct light. Preliminary results found that the 532nm wavelength laser light has a deviation in the determination of metal ions. Laser wave was analysed by water diffusion chromatography. In order to facilitate the change from large equipment to portable metal ion detection technology.
The study of Laser 532nm wavelength in Ni+·H20 for reflective effect
Authors: Zhou Hao-Lin , Wu Xin-Da , Lin Dan , Zhang Li-Qiong
Published: March 2021

The rapid development of science and technology in china, treatment of pollutants is also relatively the biggest problem in developed countries, and heavy metal pollution in many water pollution accounted for a larger proportion. The traditional analytical sampling methods include ultraviolet spectrophotometry (UV), atomic absorption spectrometry (AAS) and atomic fluorescence spectrometry (AFS), to improve timeliness, in this study, laser light method was used to preliminarily analyse the water body, using the difference of reflected facula analysis may contain metal ions in the sample. It was found that after the laser with the wavelength of 532nm was refracted in the nickel solution and distilled water, the facula reflected by the outer glass surface had a significant deviation, from the preliminary experimental results, the reflect facula area of that nickel liquid was 96.01% with respect to water. Therefore, that lase light can be used as a reference for research on miniaturize measurement equipment in the future.
Development and Characterization of Bioplastic Film from Salacca zalacca Seed Starch
Authors: Ma’mun S , Alamsyah D N , Pribadi A S
Published: March 2021

The world community has given a particular concern to environmental issues such as pollution of the marine environment due to petroleum-based plastic materials. Since petro-based plastics cannot easily be degraded in nature, bioplastics’ development is a must. Bioplastics can be made from various renewable feedstocks such as polysaccharides, protein, and fat. Salacca zalacca is one of the starch sources that can be used to manufacture bioplastics. The purpose of this study was to develop and characterize the bioplastic by use of Salacca zalacca starch. The bioplastic films were made by mixing all the raw materials at 70 oC for 40 minutes. The sample was then put into a mold and heating it in the oven at 50°C for 24 hours. The results show that an optimum condition with 4 wt% of PVA occurs at the starch concentration of 1.8 wt% with the tensile strength and the elongation of 20 N and 53%. Moreover, the optimum condition with 15 wt% of PVAc gives the tensile strength of 20 N with lower elongation (15%).
Enhancement of self-healing to mechanical properties of concrete
Authors: Abd Elzahra Israa H , Al-Sherrawi Mohannad H
Published: March 2021

Concrete is the main construction material of many structures. Exposing to loads creates cracks in concrete, which reduce the performance and durability. The decrease of concrete cracks becomes a necessity demand to ensure more durability and structural integrity of the concrete structure. Autogenous healing concrete is a kind of new smart concretes, which has the ability to reclose its cracks by means of itself. Concrete self-healing is a type of free repairs processes, which is reduce direct and indirect cost of maintenance and repairing. This work targets to inspect the mechanical properties of concrete after using two combinations of two materials (20 kg/m3 calcium hydroxide Ca(OH)2 and 2 kg/m3 sodium carbonate Na2CO3 and 30 kg/m3 calcium hydroxide and 3 kg/m3 sodium carbonate) as a partial replacement of cement to work as self-healing agents. The paper reports and study the compressive, flexural and splitting tensile strengths and ultrasonic pulse velocity tests’ results at 7, 28 and 90 days of concrete age. Use of two combinations of calcium hydroxide and sodium carbonate, as healing agents, enhanced the mechanical properties of concrete and reduced the width of concrete cracks with time. The concrete compressive strength was increased after curing for 90 days by 9.3 and 11.1 %, respectively. The flexural strength was improved by 14.3 and 15.9 %, respectively. Also, the splitting tensile strength was enhanced by 6.9 and 9.3 %, respectively.
Release Analysis of Nano-Titanium Dioxide (TiO2) from Paint: An Accelerated Weathering Experiment
Authors: Llana M J , Tolentino M S , Valeza N C C , Reyes J P , Basilia B A
Published: March 2021

Engineered nanomaterials (ENM’s), particularly TiO2 nanoparticles are being incorporated on paints due to their capabilities to enhance optical properties and to scatter UV radiation, which eventually protects the paint from discoloration. In this study, the release of these nano-TiO2 from paint was investigated. Two (2) types of paint were used, one containing pigment- and nano-TiO2 (P1), while the other only contains pigment-TiO2 (P2). The paints were subjected to accelerated weathering wherein the paints were exposed to cycles of UV irradiation and water condensation. The SEM-EDX results showed the distribution of the pigment- and nano-TiO2 on the surface of P1 and P2, and the changes in the morphologies before and after weathering. The photomicrograph revealed the formation of cracks on the surface of P1 brought about by the photocatalytic degradation due to the presence of nano-TiO2. Leachate samples were also collected weekly in the duration of the weathering test and were analysed using ICP-OES. The presence of Ti, which can be correlated to the release TiO2, on the samples was detected. The release of Ti from P1 and P2 showed a decreasing trend throughout the weathering experiment, having the following initial amounts of release: 1.38 mg/L and 2.10 mg/L for P1 and P2, respectively. Moreover, a graphical release mechanism for the nano-TiO2 release was conceptualized based on the results of the study. In general, potential release of nano-TiO2 from paints could happen since these TiO2 nanoparticles serve as a photocatalyst in the paint degradation when exposed to prolonged weathering conditions.
Material Risk Pooling: Strategies for Precast Fabrication
Authors: Ko Chien-Ho
Published: March 2021

Materials used in precast fabrication are different from those cast in the construction site. When fabricators lack production materials, they have to await the materials until the supplier transports them to the precast fabricator. The primary objective of the study is to enhance on-time delivery with relatively low inventory by leading risk-pooling concept with lateral transshipment strategy. To achieve the goal, this research develops lateral transshipment strategies by considering the characteristics and requirements of precast production. The computer simulation technique is then used to analyze the material risk pooling strategies. The proposed method can be used to analyze optimum transshipment policy for shipping the required materials from manufacturing plants that have surplus to others starving for materials. Risks of late delivery can thus be reduced.
Investigation of the Criteria for Evaluating Electrode Metal Transfer in Short Circuit Gas-Shielded Arc Welding
Authors: Bolotov S V
Published: March 2021

Based on the developed information-measuring complex, the investigation of processes of melting and electrode metal transfer during short circuit arc welding was carried out. The close relationship between the energy of the arc at the stage of its formation and the diameter of an electrode metal droplet was found. It is proposed to evaluate the transfer stability by the harmonic composition of welding current.
Effect of hot isostatic pressing on the quality of metal parts obtained by selective laser melting
Authors: Zhdanov A V , Voznesenskaya A A , Raznoschikov A S
Published: March 2021

In this work, an approach to improving the quality of material obtained by the method of selective laser melting is considered. The analysis of powder material of stainless steel is carried out. A number of samples were obtained with subsequent HIP-processing. The structure was analyzed, and the hardness of the obtained samples was measured before and after HIP treatment.
Stabilization of Root Parameters for Shielded Arc Welding
Authors: Krasikov P P , Savinov A V , Polesskiy O A , Chudin A A , Krasikova L S , Kozlov I V , Borisov D S , Filippov V V
Published: March 2021

The study revealed that the application of flux paste to the back side of the welded joint during welding of low-alloyed steels provides control over the sizes of the root and its defect-free formation. It was found that the back bead height of the root welded with flux paste is 1.5 to 3 times less than that of the root welded with the same welding variables without flux paste.
Estimation of electric loads dynamics in the gas fields of Western Siberia taking into account the life cycle of the fields
Authors: Bogachkov I M , Khamitov R N , Frayshteter V P
Published: March 2021

All gas fields go through four periods of their life cycle with their technological scheme changes. The engineering of electricity supply system for gas fields in West Siberia was performed without taking into account the final stage of their life cycle. To extend the period of profitability of low-pressure Cenomanian gas at the final stage of the life cycle an energy-intensive technology of gas compression distribution with usage of mobile compressor units (MCU) is implemented. The implementation of this technology in the gas fields requires the construction of a new electricity supply system or the reconstruction of the entire existing one. The objective of the paper is to assess the dynamics of electric loads of gas fields, considering the entire life cycle. The average annual calculated electric load for each life cycle period for active fields in West Siberia for 2019 is determined. The coefficient of increase in electric load is calculated. The tasks are solved using the empirical method (measurement, comparison) and the experimental-theoretical method (analysis and synthesis). The analysis shows that during the life cycle of a gas field, when the well outcrop and average reservoir pressure decrease over time, the calculated electrical load increases in many times.
Comparison of control methods for inverted 2-degree of freedom pendulum mounted on the cart
Authors: Sumenkov O Y , Belyaev A S
Published: March 2021

The paper considers and analyzes the existing methods of controlling systems with a deficit of control actions. Based on the analysis, it was decided to use linear controllers with feedback on the state vector of the system and to compare these methods - modal and linear-quadratic. For the study, a dynamic model was chosen, which is an inverted 2-degree of freedom (2DOF) pendulum mounted on a cart. By an iterative method, acceptable system of generalized coordinates that definitely describes the state of the model was selected. Kinematic relations that describe the position of the model in generalized coordinates were derived. Using the Lagrange procedure, a system of nonlinear differential equations describing the motion of a dynamic model was obtained. The procedure of model linearization about the upright equilibrium point was also carried out in order to synthesize control system. Based on the results of modeling, which was carried out by numerical integration method in the Matlab environment, conclusions were drawn on the applicability of these control methods and their effectiveness.
Path-building and localization system for mobile robotic platforms based on Raspberry Pi
Authors: Ivanov E A , Belyaev A S , Brylev O A
Published: March 2021

The paper demonstrates a system for detection of location of robotic platform FESTO Robotino and optimal route building. It processes data from the camera and transmits control signals to the control system of the robot. The whole system is based on Raspberry Pi. It detects robot’s current coordinates, current angular rotation, angular difference (difference between current and previous angular rotation) and displacement of the robot in its own coordinate system. It uses an ArUco marker, placed on the top of the mobile robot for that. System also builds an optimal path, when moving from one point of the surface to another, according to the permeability of the surface. The authors set the permeability of testing surfaces. Using that, a weighted graph is built through the centers of particular surfaces, which are detected via an algorithm on Raspberry Pi. The optimal path is constructed through the edges of the graph via modified Dijkstra algorithm.
Evaluation of the possibility of using multilayer nanostructured coatings to improve the output characteristics of roller screw mechanisms
Authors: Zhdanov A V , Novikova E A , Dovbysh N S , Mitrofanov A N
Published: March 2021

This article examines the effect of different coatings made of different materials on the efficiency of roller gears. Graphs of the dependences of the parameters of each coating are plotted. Tables of changes in the efficiency parameters and friction coefficients for the studied materials are given.
Results of modeling the operation of the hydraulic pump in the Matlab-Simulink application and testing on the diagnostic bench
Authors: Vlasov Yu , Meshcheriakov M , Alushkin T
Published: March 2021

The article provides information on the design of the original stand for diagnostic tests of hydraulic equipment and lubrication systems of various transport and self-propelled vehicles. The scientific novelty of the work is the concept of a mobile diagnostic stand with extended testing capabilities at various drive shaft speeds. As an example of the functional capabilities of the stand, the test results of the NSh-32 pump of the fourth class of the company “Hydrosila” are presented. No publicly available data on the characteristics of the investigated hydraulic pump was found. Based on the test results, a comparative analysis and discussion of the performance of this sample with a pump of the previous class was carried out. Additionally, data on the capabilities of the measuring complex for measuring the parameters of an internal combustion engine, in which the hydraulic pump under consideration can operate, is presented.
The possibility to use Bandsaw Dynamic Tensioning in Bandsaw Machines
Authors: Shilko V K , Slepchenko V A , Slepchenko I V
Published: March 2021

The authors considered the mechanism of motion transmission to wood-cutting band saws, using the effects of their dynamic tension during operation, within the general statements of the flexible link transmission theory.
Thermogravimetric analysis of epoxy-based carbon fiber reinforced polymers modified by carbon fillers
Authors: Burkov M V , Eremin A V
Published: March 2021

The paper presents the results of thermogravimetric/differential scanning calorimetry investigation of hybrid thermoset CFRPs modified by the addition of single-wall carbon nanotubes and milled carbon fibers. Specimens were tested using NETZSCH STA 409 PC/PG with the following parameters: heating from ambient temperature to 873 K with a rate of 15 K/min; Ar flow rate of 50 ml/min. The content of the carbon filler in CFRP was varied allowing to establish some regularities in thermal and physical properties.
Nomination Violence in Uganda’s National Resistance Movement
Authors: Kjær Anne Mette , Katusiimeh Mesharch W
Published: March 2021

Institutional explanations of intra-party violence rarely address political economy dynamics shaping the institutions in question, and therefore they fail to understand their emergence and their stability. Specifically, focusing on institutional factors alone does not enable a nuanced understanding of candidate nomination violence and why some constituencies are peaceful while others are violent. This article theorizes nomination violence in dominant-party systems in sub-Saharan Africa. Drawing on political settlement theory, it examines the nature of nomination violence in Uganda’s October 2015 National Resistance Movement (NRM) primaries. We argue that the violence is a constitutive part of Uganda’s political settlement under the NRM. Nomination procedures remain weak in order for the NRM ruling elite to include multiple factions that compete for access while being able to intervene in the election process when needed. This means, in turn, that violence tends to become particularly prominent in constituencies characterized by proxy wars, where competition between local candidates is reinforced by a conflict among central-level elites in the president’s inner circle. We call for the proxy war thesis to be tested in case studies of other dominant parties’ nomination processes.
Concomitant Processing of Choice and Outcome in Frontal Corticostriatal Ensembles Correlates with Performance of Rats
Authors: Handa Takashi , Harukuni Rie , Fukai Tomoki
Published: March 2021

The frontal cortex-basal ganglia network plays a pivotal role in adaptive goal-directed behaviors. Medial frontal cortex (MFC) encodes information about choices and outcomes into sequential activation of neural population, or neural trajectory. While MFC projects to the dorsal striatum (DS), whether DS also displays temporally coordinated activity remains unknown. We studied this question by simultaneously recording neural ensembles in the MFC and DS of rodents performing an outcome-based alternative choice task. We found that the two regions exhibited highly parallel evolution of neural trajectories, transforming choice information into outcome-related information. When the two trajectories were highly correlated, spike synchrony was task-dependently modulated in some MFC-DS neuron pairs. Our results suggest that neural trajectories concomitantly process decision-relevant information in MFC and DS with increased spike synchrony between these regions.
Exploring gender differences in trajectories of clinical markers and symptoms after left ventricular assist device implantation
Authors: Denfeld Quin E , Faulkner Kenneth M , Davis Mary Roberts , Habecker Beth A , Chien Christopher V , Gelow Jill M , Mudd James O , Hiatt Shirin O , Grady Kathleen L , Lee Christopher S
Published: March 2021

Aims

Despite well-known gender differences in heart failure, it is unknown if clinical markers and symptoms differ between women and men after left ventricular assist device (LVAD) implantation. Our aim was to examine gender differences in trajectories of clinical markers (echocardiographic markers and plasma biomarkers) and symptoms from pre- to post-LVAD implantation.

Methods and results

This was a secondary analysis of data collected from a study of patients from pre- to 1, 3, and 6 months post-LVAD implantation. Data were collected on left ventricular internal end-diastolic diameter (LVIDd) and ejection fraction (LVEF), plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP), and soluble suppressor of tumorigenicity (sST2). Physical and depressive symptoms were measured using the Heart Failure Somatic Perception Scale and Patient Health Questionnaire-9, respectively. Latent growth curve modelling was used to compare trajectories between women and men. The average age of the sample (n = 98) was 53.3 ± 13.8 years, and most were male (80.6%) and had non-ischaemic aetiology (65.3%). Pre-implantation, women had significantly narrower LVIDd (P < 0.001) and worse physical symptoms (P = 0.041) compared with men. Between pre- and 6 months post-implantation, women had an increase in plasma sST2 followed by a decrease, whereas men had an overall decrease (slope: P = 0.014; quadratic: P = 0.011). Between 1 and 6 months post-implantation, women had a significantly greater increase in LVEF (P = 0.045) but lesser decline in plasmoa NT-proBNP compared with men (P = 0.025).

Conclusion

Trajectories of clinical markers differed somewhat between women and men, but trajectories of symptoms were similar, indicating some physiologic but not symptomatic gender differences in response to LVAD.
A systematic review of reach, adoption, implementation and maintenance of Internet-based interventions to prevent eating disorders in adults
Authors: Nacke Barbara , Zeiler Michael , Kuso Stefanie , Klesges Lisa M , Jacobi Corinna , Waldherr Karin
Published: March 2021

Background

There is a growing body of research and evidence for the efficacy of Internet-based eating disorder (ED) prevention interventions for adults. However, much less is known about the reach, adoption, implementation and maintenance of these interventions. The RE-AIM (reach, efficacy/effectiveness, adoption, implementation, maintenance) model provides a framework to systematically assess this information.

Methods

A literature search was conducted in PubMed, Web of Science and PsycINFO for articles published between 2000 and 2019. Additionally, reference lists of the studies included and existing reviews published until the end of 2020 were searched. Sixty original articles describing 54 individual studies fulfilled inclusion criteria. Data were extracted for a total of 43 RE-AIM indicators for each study. Fostering and hindering factors for reach, adoption, implementation and maintenance were assessed qualitatively.

Results

Overall reporting rates were best for the RE-AIM dimensions reach (62.6%), implementation (57.0%) and effectiveness (54.2%), while adoption (24.2%) and maintenance (21.5%) had comparatively low overall reporting rates. Reporting on indicators of internal validity, such as sample size, effects or description of interventions was better than indicators relevant for dissemination and implementation in real-world settings, e.g. characteristics of non-participants, characteristics and representativeness of settings, and data to estimate cost.

Conclusions

Because most Internet-based ED prevention interventions are provided in a research-funded context, little is known about their public health impact. Better reporting of factors determining external validity is needed to inform dissemination and implementation of these interventions.
The Effects of GC-Biased Gene Conversion on Patterns of Genetic Diversity among and across Butterfly Genomes
Authors: Boman Jesper , Mugal Carina F , Backström Niclas
Published: March 2021

Recombination reshuffles the alleles of a population through crossover and gene conversion. These mechanisms have considerable consequences on the evolution and maintenance of genetic diversity. Crossover, for example, can increase genetic diversity by breaking the linkage between selected and nearby neutral variants. Bias in favor of G or C alleles during gene conversion may instead promote the fixation of one allele over the other, thus decreasing diversity. Mutation bias from G or C to A and T opposes GC-biased gene conversion (gBGC). Less recognized is that these two processes may—when balanced—promote genetic diversity. Here, we investigate how gBGC and mutation bias shape genetic diversity patterns in wood white butterflies (Leptidea sp.). This constitutes the first in-depth investigation of gBGC in butterflies. Using 60 resequenced genomes from six populations of three species, we find substantial variation in the strength of gBGC across lineages. When modeling the balance of gBGC and mutation bias and comparing analytical results with empirical data, we reject gBGC as the main determinant of genetic diversity in these butterfly species. As alternatives, we consider linked selection and GC content. We find evidence that high values of both reduce diversity. We also show that the joint effects of gBGC and mutation bias can give rise to a diversity pattern which resembles the signature of linked selection. Consequently, gBGC should be considered when interpreting the effects of linked selection on levels of genetic diversity.
Temporalis Muscle Thickness as an Indicator of Sarcopenia Is Associated With Long-term Motor Outcomes in Parkinson’s Disease
Authors: Chung Seok Jong , Kim Yun Joong , Yoo Han Soo , Jung Jin Ho , Baik KyoungWon , Lee Hye Sun , Lee Yang Hyun , Hong Ji-Man , Sohn Young H , Lee Phil Hyu
Published: March 2021

Background

To investigate the relationship between temporalis muscle thickness (TMT) at baseline as a surrogate marker for sarcopenia and long-term motor outcomes in patients with Parkinson’s disease (PD).

Methods

We enrolled 249 patients with drug-naïve early-stage PD (119 males and 130 females, follow-up > 3 years). Baseline TMT of each patient was measured on the axial plane of T1-weighted images. The association between baseline TMT and long-term motor outcomes in PD was assessed using Cox regression models for levodopa-induced dyskinesia, wearing-off, and freezing of gait and a linear mixed model for the longitudinal increases in levodopa-equivalent dose per body weight over time. Statistical analyses were performed separately for sex if an interaction effect between TMT and sex was assumed.

Results

TMT differed substantially between the sexes, and male PD patients had higher TMT (6.69 ± 1.39 mm) than female PD patients (5.64 ± 1.34 mm, p < .001). Cox regression models demonstrated that baseline TMT was not associated with the risk of developing levodopa-induced dyskinesia, wearing-off, or freezing of gait during the follow-up period. The linear mixed model was applied separately for sex and demonstrated that higher TMT at baseline was associated with slower increases in levodopa-equivalent dose per body weight in male PD patients, but not in female PD patients.

Conclusions

This study demonstrated that baseline TMT could be an indicator of the longitudinal requirement for dopaminergic medications in male patients with PD, suggesting that sarcopenia may have a detrimental effect on disease progression in PD in a sex-specific manner.
Threat not solution: gender, global health security and COVID-19
Authors: Harman Sophie
Published: March 2021

COVID-19 has led to long overdue visibility of the gendered determinants and impacts of health emergencies and global health security. This article explores why gender was neglected in previous health emergencies, what led to change in visibility of gender issues during the first six months of the COVID-19 pandemic, and the implications of such change for understanding the relationship between gender and global health security. The article explores the question of neglect by drawing on original research into the 2014–16 Ebola outbreak in Sierra Leone, its aftermath and implications for future pandemic preparedness. The article then looks in detail at the research efforts, funding, epistemic community activism and impact of COVID-19 to explain why gender received high profile political attention and acknowledgment. The article argues that the change in visibility, research and advocacy around gender equality during the COVID-19 outbreak does not demonstrate an advancement in gender equality in global health. To the contrary, such visibility reinforces the inherent problems of global health security evident in the 2014–16 Ebola outbreak that create and reproduce binaries of neglect and visibility, and hierarchies of the global health issues that matter, the people that matter and the women that matter. What unites neglect and visibility of gender in global health security is that gender is understood as solution rather than threat. Combined these factors make gender equality incompatible with global health security.