bluuebunny/crossref_metadata_2025 huggingface dataset:
Pipe sizing of district cooling distribution network including in energy transfer station
Authors: Lisaba E B , Augusto G L
Published: March 2021

A district cooling system (DCS) distributes chilled water to different buildings connected to the main plant. The benefits of a DCS include greatly increasing energy efficiency and decreasing life cycle operation costs. The installation, maintenance, and design of a DCS can be expensive, however. Therefore, means of decreasing costs without cutting quality is necessary. Given this, a hypothetical DCS is presented with a constant temperature difference set-point of 9°C. The DCS was set to have a system diversity of about 80%. Hydraulic calculation will be used in the study in order to determine the smallest possible pipe sizes that would permit normal operation below allowable limits. The network is divided into 3 parts; namely the main line (ML), the plot take-off (PTO), and the plate-type heat exchangers (PHEs). The DCS will have a piping network connected to 12 energy transfer stations, each with 3 sets of PHEs. Initial guess values of pipe dimensions and friction factors will first be calculated using continuity and the Von Karman equation. A single-variable Newton-Raphson method is then used on the implicit Colebrook-White equation to estimate the actual friction factor for each pipe. Then, the calibrated pipe sizes will be determined by cross-referencing theoretical values with industry-standard sizes as specified in ASHRAE. In calculating the friction factor, it was found that the values increase as the given tonnage decreases, thus implying a decrease in pipe size as the chilled water flows toward the last building. The entire study was conducted on MATLAB. It must be noted that the study is only limited to the selection and design of a simple DCS.
Finite element analysis of frictional coefficients in press fit pins
Authors: Gonzaga J , Ubando A T , Arriola E , Moran R L , Lim N R E , Mercado J P , Conversion A , Belarmino D
Published: March 2021

The automotive industry places electronic components in vastly different conditions compared to that for residential purposes. Thus, there are certain components that have found an essential use in this industry. One such component is the press fit pin. The press fit pin is seen as an alternative to soldering because it is cheaper to implement and more reliable at times. All technologies however, come with disadvantages. One of the common issues encountered by press fit pins are the excessive stresses on both the pin and the hole during insertion which tend to cause deformation or cracks in the substrate material. Because of this, the main topics of research on press fit pins are most commonly on the insertion forces and retention forces present. These forces occur on the interfaces between the pin and the hole where it is inserted. Therefore, there have been several studies on the friction between the two components. The studies however, only explored the frictional coefficient of their present system which reduces its applicability on other designs. This work seeks to present an in-depth finite element analysis on the effects of varying frictional coefficients would have on the equivalent stress and retention forces present on the press fit pins.
HALE UAV ITB perpetual flight
Authors: Moelyadi Mochammad Agoes , Zulkarnain Muhammad Fikri
Published: March 2021

The challenge developing High Altitude Long Endurance (HALE) UAV is to obtain the ability endurance of more than 24 hours (perpetual flight). The ability to fly for a long time needs to consider: high aerodynamic efficiency, high motor-prop efficiency, hybrid battery-solar panel energy source, light weight structures, efficient control, and optimum flight mission. This paper discusses about strategy, method and requirements to calculate perpetual flight mission for the case of HALE UAV ITB.
Interval forecasting model for time series based on the fuzzy clustering technique
Authors: Vovan T , Phamtoan D
Published: March 2021

This paper proposes the forecasting model for the fuzzy time series based on the improvement of the background data and fuzzy relationship (IFTC). This algorithm is built based on the fuzzy cluster analysis which the suitable number of clusters for series is considered. The problem of interpolating data according to fuzzy relationships of time series in the trapezoidal fuzzy number is also established. The proposed model is illustrated step by step by a numerical example and effectively implemented by the Matlab procedure. The IFCT has advantages in comparing to other models via the several indexes such as the MAE, MAPE and MSE with the Enrollment dataset.
Noise filtering algorithm for control of motion systems
Authors: Wah Hnin Lae , Sin Aung Myo Thant
Published: March 2021

Measurement noise and external disruptions are problematic in real world applications and every control system design. These unwanted disturbances affect the measured output signal and cause the system to provide an inaccurate output. We need to eliminate these noises for stabilizing of the control system design. In this paper, we propose how to eliminate effectively the noises in motion control systems using the Kalman filter. We investigate practically the Kalman filtering algorithm based on the measurements generated by the encoder sensor fixed on DC motor. The Kalman algorithm is used for noise filtering because it is recursive algorithm and it can handle the noises that occur when the sensor is used to read data. The performance of KF method is enhanced by adjusting its parameters according to the innovation requirements. In the experimental results, the velocity estimation of the Finite-difference (FD) method is demonstrated to compare with the velocity estimation of the Kalman filtering (KF) method.
Sliding speed effect in press-fit connection using Finite Element Analysis
Authors: Ubando A T , Gonzaga J , Conversion A , Belarmino D , Arriola E , Lim N R E , Moran R L , Mercado J P
Published: March 2021

Solderless press-fit contacts in power module packages are now gaining more attention in the automotive industry especially in hybrid electric vehicles because of the Restriction of Hazardous Substances (RoHS) directive to eliminate lead-based connections. The production of press-fit assembly is also faster, more convenient, safer, and cheaper than soldered connections. In this paper, the effect of insertion speed of pin to the press-in force as well as the pull-out speed to the retention force was investigated using finite element analysis. An eye-of-the-needle (EON) shape compliant pin with general dimensions was adapted and a transient structural analysis in ANSYS mechanical was used to add and vary the speed of the press-fit pin geometry. Four simulations were conducted with different speeds. The results obtained by FEA show that the speed when kept at constant has no significant effect both on the press-in and retention force. However, when the speed changes due to acceleration, the press-in and pull-out force are both affected.
Study on replication of a nonlinear dynamical system’s trajectory using a machine learning technique
Authors: Truong Tri Quoc
Published: March 2021

Nonlinear system exhibits various solution orbits depending on varying parameters. It is important to detect the system’s behavior. In some cases, however, the mathematical modeling of the dynamic is completely unknown. By using a recent advance in the Machine Learning technique named Reservoir Computing, we replicate the solution orbits based only on data collected along with time evolution. We numerically confirm the effectiveness of Reservoir Computing in time series prediction.
Using ANFIS technique in prediction of reverse flow in a solar chimney
Authors: Huynh Minh-Thu T , Doan Thinh N , Nguyen Y Q
Published: March 2021

In solar chimney, in order to save resources in Computational Fluid Dynamics (CFD), this study aims to combine Adaptive Neuro-Fuzzy Inference System (ANFIS) to predict reverse flow and investigate the ventilation performance. The inputs to the model are heat flux in the range of 200-1000W/m2, gap of 0.04-0.25m and height of 1-1.4m, while outputs are penetration depth and mass flow rate. The results of R2 and RMSE are reasonable for training and testing data, hence the ANFIS model is validated.
100kW grid-connected renewable energy system design for an educational campus in Tarlac: A step towards green energy campus development
Authors: Rombaoa Adam
Published: March 2021

This paper discussed the design of a grid-connected renewable energy system for an education institution. One-year energy consumption and the hourly load of the institution were determined to design the energy system. HOMER Pro and What’sBest! 16.0 for Microsoft Excel optimization tools were used in the design, consisting mainly of wind turbines and solar PV. Weibull probability function and the simplified irradiance model were used to predict the wind turbine and solar PV power output in the Microsoft Excel spreadsheet. Results showed that the mean velocity at 50 m reference height is 3.886 m/s. The annual solar PV system energy produced based on the HOMER Pro simulation and What’sBest! was found to be 170,939 kWh/yr and 189,454 kWh/yr, respectively. HOMER Pro and What’sBest! iteration results showed that the optimum number of components are 303 and 0 for solar PV and wind turbine, with net present costs of Php 23,388,612 and Php 22,769,478, respectively. With this optimum result, emissions can be reduced by up to 51%, a financial saving of at least Php 1, 970, 145 per year can be achieved with payback period of 5 years.
Design of small scale, axial flux, permanent magnet wind generator in Vietnam
Authors: Tien Le Hung
Published: March 2021

This paper presents the design of light weight, small scale, disk type, axial flux, permanent magnet (AFPM) generator for wind applications. This article also shows the partial works done under state projects in renewable energy in Vietnam to find out the most suitable, reliable, self - made wind generator types for rural and remote areas. The collaboration project of Hochiminh City University (HCMUT) - Hanoi University of Science and Technology (HUST) - Berlin University of Technology (TU Berlin) resulted in some small scale, axial flux, slow speed, permanent magnet (PM) generators which best suited for Vietnam countryside areas. The researches in rare earth PM from HUST, the electrical machine design knowhow of TU Berlin and the renewable energy research experiences of HCMUT, especially in slow speed wind turbines have shown many promising applications. The small scale, permanent magnet wind generator for remote and rural areas as a cheap source of power supply is necessary in Vietnam. Though there are many large wind farms built in many provinces recently but the needs for telecommunication, family lighting in the heights, mountain, unreachable electric grid communes are still necessary. Further research should be done to match the generator for hydro power stations, diesel coupled internal combustion engine. These prospects are very promising.
Energy equity analysis in Metro Manila using household expenditure data
Authors: Tayag Christian Roice , Lopez Neil Stephen
Published: March 2021

Energy poverty in the Philippines has been prevalent, but current energy equity metrics in the Philippines are done only on a national level. Lorenz curve and Gini coefficient are concepts traditionally applied in economics to measure wealth inequality. In this paper, the authors will adapt the methodology used by Jacobson to measure energy inequality in Metro Manila for 2015 using energy expenses of households retrieved from the Family Income and Expenditure Survey conducted and published by the Philippine Statistics Authority every three years containing energy expenses, income, and socio-economic identifiers of a household. The main energy resources listed in the survey are electricity, LPG, kerosene, fuelwood, charcoal, and biomass residue. To translate energy expenses to energy consumption, historical costs available from public records are used in conjunction with the fuels’ calorific values. From there, Lorenz curves and Gini coefficients are calculated for districts and cities in Metro Manila. Further comparison reveals the relationship of income and energy consumption Gini coefficients in the region. Based on the results, the authors include recommendations to improve the use of Lorenz curve and Gini coefficient as a metric in quantifying energy equity.
Experimental Study in Measuring Pressure Loss at Micro Channel
Authors: Hendrarsakti J , Huda R M , Junianto E
Published: March 2021

The objective of study was to conduct experimental study in measuring the pressure loss due to the major and minor loss in fluid flow at straight and bent micro channel. Test channel had circular cross-sections with hydraulic diameters of 118 µm to 1203 µm for straight and 348 to 1203 for bent micro channels. The results showed that losses for larger diameter of straight channel were well predicted. The bent channel showed that the loss coefficient values were higher if the Reynolds number got smaller.
The Efficiency Estimate of PV Cell under various wind velocities
Authors: Nguyen Duy Tue , Nhut Do Tri
Published: March 2021

It is a good chance to harness solar energy for Vietnam to geographic location is near to the equator with the high intense radiation. Photovoltaic (PV) cell is the device to convert directly solar energy into electrical energy. However, its efficiency is strictly impacted by the PV cell surface’s temperature which depends on wind velocity, surrounding temperature, radiation and dust. For a long time, computational modelling has been a good choice for engineers to simulate their products. Currently, some softwares like Ansys Fluent, Comsol Multiphysics are chosen to simulate the thermal performance of product. In this paper, authors used Computational Fluid Dynamic (CFD) – Autodesk to estimates the PV cell temperature, then find out its corresponding efficiency. A 3 dimensions model of PV cell with some layers was created by Inventor software, and then simulated under various wind velocities like 0.5m/s, 1.5m/s, 2.5m/s, 3.5m/s, 4.5m/s, 5.5m/s and 6.5m/s to find out the PV cell corresponding temperatures. The solar radiation parameter in Ho Chi Minh city in April was established for simulation. With the same surrounding temperature at 30°C, the result shows that the highest PV cell surface’s temperature of 84.8°C with wind velocity of 0.5m/s will drop to 49.81°C with the wind velocity of 3.5 m/s. When the wind velocity is continue increased, the drop of temperature is trivial. The PV cell efficiency at wind velocity of 6.5m/s is only 2.75% higher than that of wind velocity of 3.5m/s. Therefore, when choosing cooling PV cell by air, the air velocity should be chosen at 3.5 m/s to save energy.
Eutectic potassium chloride (KCl) solution as phase change material (PCM) for fish cold storage
Authors: Sukoco R K , Indartono Y S , Mujahidin D
Published: March 2021

Traditional fishermen need to buy ice blocks every time they go fishing, thus impacting their expenses. To potentially save money, an alternative solution using phase change material (PCM) is proposed. PCM contained properly is reusable, thus reducing expenses for fishermen. Eutectic potassium Chloride (KCl) solution is utilized as PCM, which has melting temperature of -10.7 °C and heat of fusion of 253 kJ/kg. The PCM is used to substitute ice as the currently primary source to chill fish in storage. The solution is contained in an aluminium-foil zip-lock bags, each containing 670 grams of solution. The experiment uses two Polystyrene boxes, one containing 10 pouches of eutectic KCl solutions as PCM and the other containing ice cubes with the same mass. Two kg of fish is stored for 24 hours in each box. Thermal analysis shows that the box temperature containing KCl solution is steady for the 24 hours of experiment. Starting to be steady at -2.8 °C from room temperature, the box temperature increases slowly, reaching only 2.1 °C after 24 hours. Organoleptic test shows that the fish stored inside KCl box loses 1.39 quality points on average, compared to 1.89 in ice box after 24 hours. Therefore, the fish in the PCM box is slightly fresher than the one stored using ice cubes.
Transport Emissions Modeling using Google Maps: An alternative approach for vehicle flow analysis
Authors: Rito J E , Lopez N S
Published: March 2021

Continuous measurements of transport emissions are considered key issues for air pollution management in the transportation sector. In some instances, researchers may come across difficulties in doing transport emissions modeling such as overcomplexities and laborious methodologies. In this regard, the authors are introducing a novel method of doing a transport emissions modeling by utilizing Google Maps data. By getting the average travel time of a road segment and the corresponding length, the average speed can be obtained. This speed will be used to identify the flow of vehicles in terms of Passenger Car Unit (PCU) through a speed-flow curve on the basis of a Roadside Frictions Index (RSFI). PCU percentages are derived from the actual counting of vehicles using the street view features of Google Maps. Once the PCU count and the PCU percentages are established, the actual number of vehicle flow per type can now be determined. Consequently, emissions loads are calculated by multiplying the vehicle flow and road length to emissions factors derived from reliable sources.
Using Logarithmic Mean Divisia Index method (LMDI) to estimate drivers to final energy consumption and emissions in ASEAN
Authors: Lisaba E B , Lopez N S
Published: March 2021

The ASEAN is currently trying to mitigate the amount of CO2 emissions per country. This is not only to contribute to the worldwide goal of lessening greenhouse gases, but to also ensure the safety of its member states by combatting the effects of climate change. The effects as stated by the IPCC, such as rising water levels, rising ambient temperature, and an increase in the frequency of tropical storms, can greatly endanger members of the ASEAN. It must be noted that a majority of its members are archipelagic, have areas of extreme poverty, and rely on agriculture for production. Therefore, the temporal logarithmic mean Divisia index (LMDI) has been conducted in order to determine the possible drivers that cause the changes in CO2 emissions per year for all ASEAN member countries. The drivers of CO2 were divided into the population, economic activity, energy intensity, and energy structure effects. CO2 emissions per fuel type were calculated using their respective emission factors. Knowing which drivers constitute the most CO2 emissions in a country would help pinpoint which areas could be worked on. It was found that Indonesia, Brunei Darussalam, and Lao PDR had the most impressive decrease in CO2 emissions due to energy intensity and structure effects. A majority of the other countries have either stayed constant or even increased CO2 emission output per year from each effect. Therefore, general policies based on the success of these countries that could be applied for each member country are recommended in this study.
Assessment breaking strength the chassis of Multi-purpose forest fire fighting vehicle
Authors: Tung Nguyen Thanh , Van Luong Van , Van Nguyen Thai
Published: March 2021

Chassis is a main component of the automobile, during the operation of the chassis, it is fail to fatigue damage or break. Therefore, in the process of designing the chassis, it is important to study the durability to destroy the chassis. The paper presents the results of analysing breaking strength chassis of multi-purpose forest fire fighting vehicle by Ansys Workbench software to determine stress, strain in some cases of road movement. The results of the study underlie a scientific for completing the structure of multi-purpose forest fire fighting vehicle.
Effects of hybrid flame-retardant fillers on fire-resistive and mechanical properties of solvent-borne intumescent coatings
Authors: Yew Ming Chian , Ooi Guo Jie , Yew Ming Kun , Saw Lip Huat , Beh Jing Han , Ng Tan Ching , Yeo Wei Hong
Published: March 2021

The aim of this research project was to investigate the effects of hybrid flame-retardant fillers on the fire protection and mechanical properties of solvent-borne intumescent coatings. Formulations of intumescent coatings with different combinations of flame-retardant fillers were developed and investigated through Bunsen burner test, adhesion strength test and Scanning Electron Microscopy (SEM). It was found that the formulation of intumescent coating was optimized with four combinations of flame-retardant fillers in proper compositions and had improved the fire protection performance and mechanical properties of the coating. In overall, filler compositions of coating sample D (1 wt.% nano CES/ 2 wt.% expandable graphite/ 1 wt.% zinc borate/ 4 wt.% calcium silicate) had contributed to positive fire protection performance (equilibrium temperature of 190 °C) and adhesion strength (2.62 MPa). Significantly, the incorporation of an appropriate combination of hybrid nano CES bio-filler, expandable graphite, zinc borate and calcium silicate had led to a better fire protection performance and mechanical properties of the solvent-borne intumescent coating.
Influences of macro polypropylene fibre-reinforced lightweight concrete incorporating recycled crushed LECA aggregate
Authors: Yew Ming Kun , Yew Ming Chian , Beh Jing Han , Saw Lip Huat , Lim Siong Kang , Lee Foo Wei , Lee Yee Ling
Published: March 2021

The huge amount disposal of light expanded clay aggregate (LECA) had become a serious environmental issue across the globe which represents an immediate threat to the environment. One of the potential solutions is to incorporate these wastes into construction materials, mainly concrete. These waste materials are abundant and easily available. The addition of recycled crushed LECA creates void space in the concrete which helps in decreasing the density of concrete, and reducing the dead loads needed to be sustained for buildings. In this study, different volume fraction (0, 0.15, 0.3 and 0.45%) of macro polypropylene (MPP) fibre have been used to enhance the strength properties of lightweight concrete (LWC). The combination of lightweight LECA and MPP fibre have been used to achieve compressive strength between 25 to 40 MPa with a density ranged between 1800 to 2100 kg/m3. It is found that the addition of MPP fibres at an optimum volume fraction concrete enhances the compressive strength. Hence, the findings of this research revealed that it can be used as an alternative solution for concrete industry.
Comparison of vibrations of high-speed bearings driven by flat layer belts
Authors: Murcinkova Z
Published: March 2021

The paper presents the results of comparison measuring of absolute vibrations for textile machine driven by flat layered belts with high velocity 50-60 m/s. The dynamic properties of flat belt are important as the flat belt surface is in direct contact with shaft of special textile bearing (115,000-135,000 rpm). Interaction of textile bearing vibration and driven belt may produce significant amplitude and frequency vibration modulation influencing the torsional vibrations and kinematic slip of rolling elements and additional loading of cage. Thus, the bearing life is significantly shortened what is undesirable effect. However, the dynamic properties of driving flat belt are able to influence the vibration of high-speed bearing as it was measured. The two tested flat belts involved one polyester and aramid fabric, respectively, keeping same temperature, belt tension, rotational speed and driven forty bearings. The belt involving the aramid fabric brought the promising results.
Manufacturing lateral flow tests for tuberculosis diagnosis: choosing a reactants completion and sensing regime
Authors: Byzova N A , Sotnikov D V , Zherdev A V , Dzantiev B B
Published: March 2021

To develop technologies for rapid out-of-laboratory diagnoses of tuberculosis based on the level of specific antibodies, the requirements for the antibody preparations and their combinations used in the analysis were studied, as well as procedures for the manufacture of a multimembrane composite. A comparative characterization of various recombinant antigens in terms of diagnostic sensitivity and specificity was carried out. The possibility of increasing the diagnostic sensitivity to 15%–20% when using multi-antigen mixtures (cocktails) of antigens was shown. The requirements for the manufacture of multi-membrane composites—test strips for diagnostics—were determined. The correspondence of the minimum detectable level of specific antibodies to the diagnostic threshold of 0.2 mg/ml was shown. Testing of test systems via the most effective cocktails of antigens on blood samples from healthy and sick subjects was carried out.
Study of engineering properties of lightweight geomaterial (LWGM) stabilized by Waste of Buton Asphalt
Authors: Marfu’ah N , Harianto T , Irmawaty R , Muhiddin A B
Published: March 2021

Material with high strength but has the lightest density that can be tolerated is the main purpose of doing a research about soil improvement. This research aims to develop a lightweight geomaterial (LWGM) by substituting of the soft soil with Expanded Polysterene (EPS) which is stabilized with Waste of Buton Asphalt (WBA). The variation of the WBA used was 3%, 5%, 7% and 9%, while the variation of the EPS used was 0.15% and 0.30%. Curing of the specimens was carried out for 7 and 28 days to see the effect of curing on the pozzolanic reaction to the specimens strength. The test results shows that soil substitution with EPS reduce the density by 10% - 25%. Even though it decreased comparing to the strength of the sample without additional of EPS, the CBR and UCS LWGM values are still classified as good performance and can be tolerated. Based on the results of curing samples, during the curing period of 7 days, the CBR value increased up to 5 times at 0.15% EPS and 4 times at 0.30% EPS. Meanwhile, during the 28-day curing period, the CBR value increased up to 10 times at 0.15% EPS and 6 times at 0.30% EPS. Meanwhile, the UCS value after curing 7 days is 12 times - 48 times and after curing 28 days is 15 times - 63 times greater than untreated soils.
Incident Clustering in the Warehouse Workspaces by Using Text Mining
Authors: Syaani F A , Irhamah  , Mukarromah A , Fithriasari K
Published: March 2021

Incidents can occur anytime and anywhere whether intentional or unintentional, especially in the industrial area. To prevent the incident, an analysis is needed to find out the patterns that formed based on the information from incident reports. The goals of company are to be able to identify and take action to deal quickly if some incident happens. Text Mining is done by applying the bigram technique to form the incident patterns. The analytical method used is K-Means Clustering and Hierarchical Clustering. In addition, a feature selection is also used by applying the Genetic Algorithm method to obtain optimal features. The results obtained state that the feature selection process is very influential on the formation of incident clusters. When compared, the K-Means Clustering and Hierarchical Clustering methods have different effects on each warehouse sector. The best results in the Sector of Life Style and Sector of Technology are formed by using the K-Means Clustering method while in the Sector of Consumer, Retail and SPL the best cluster results are obtained based on the Hierarchical Clustering method.
Synthesis and characterization of linear multi-functional phosphazene structures for polymer cross-linking
Authors: Chernysheva Anna I , Esin Andrey S , Soldatov Mikhail A , Bredov Nikolay S , Kireev Vyacheslav V , Oberemok Volodymyr V , Sirotin Igor S , Gorlov Mikhail V
Published: March 2021

Phosphazenes are a well-studied class of organometallic compounds with perspective characteristics, already tested in various applications. However, until now, three-dimensionally crosslinked structures based on them are primarily obtained by irradiation (that is UV and Cobalt-60). It is generally accepted that such processes proceed via the mechanism of the cleavage of C-H bonds present in the organic substituents, which clearly indicates the lack of selectivity and the impossibility to control the crosslinking degree and distribution. Within this article, multifunctional organosubstituted structures based on the short-chain penta-functional trichlorophosphazodichlorophosphonyl with eugenol and methacrylic fragments were obtained. All products were characterized by1H and31P NMR spectroscopy and MALDI-TOF mass spectrometry. The tendency of compounds with linear methacrylic substituents to undergo the phosphazene-phosphazane rearrangement, so that the dominant reaction product turns to the tetrasubstituted derivative, has been shown. All the obtained compounds can be used as the independent monomers to obtain rigid hybrid organo-inorganic matrices, as well as polyfunctional crosslinking agents for various polymers.
Self-contained drilling assembly
Authors: Belozertseva L Yu
Published: March 2021

Based on the analysis of technologies and equipment for the construction of borehole, the necessity and advantages of self-contained drilling assemblies are revealed and substantiated. The experience of engineering and application of such facilities is generalized. The key requirements to be imposed on a self-contained percussion drilling assembly are formulated. This paper can awaken interest of researchers and practitioners in mining machine engineering.
Ion-plasma coatings performance properties improvement obtained by arc deposition
Authors: Bogdanovich V I , Giorbelidze M G
Published: March 2021

Influence of micro-droplet phase content in erosion products of cathodes made of various materials on coating properties produced by vacuum ion-plasma electro-arc method has been revealed. Amount of micro-droplet phase and its fractional content in a plasma jet have been researched. Coefficient standard distribution of micro-droplet phase content depending on cathode material and production conditions, distance from the cathode to the deposition surface, arc current and the temperature of the cathode surface have been obtained. General manufacturing methods and design concepts to reduce micro-droplet phase have been formulated.
Analysis of contact strength of spherical roller transmission with double-row pinion
Authors: Lustenkov M E , Moiseenko A N
Published: March 2021

This paper presents a detailed description of the design of the spherical roller transmission. The pinion has two rows of rollers; the axes of the rollers are located on conical surfaces. When the transmission is operating, the pinion performs a regular precession and the rollers are in contact with the teeth of the stationary and driven central gears. The transmission provides high reduction ratios in a lightweight, compact package. The center of mass of the pinion is located on the axis of rotation of the drive shaft, which reduces the axial moment of inertia and improves the balance of the system compared to double-pinion planetary gears mounted on the drive shaft with eccentricity. Rolling bodies are used in place of teeth, which leads to improved efficiency. The main performance criterion is the contact strength of the teeth of the driven central gear. An equation to calculate maximum contact stresses has been derived by using Hertz theory. An algorithm for calculating the number of the rollers simultaneously engaged and transferring the load is proposed.
Experimental estimation of efficiency and kinematic accuracy of a spherical roller transmission
Authors: Lustenkova E S
Published: March 2021

Spherical roller transmissions with double-row pinions provide high reduction ratios in drives with a compact and lightweight design. The transmissions can be used as mechanical modules in kinematic chains of robots and manipulators. The pinion has two rows of coaxially arranged rollers and, when in operation, performs a regular precession. The paper examines the characteristics of an experimental model of a speed reducer with a spherical roller transmission with a reduction ratio of 44. The arrangement of the test rig as well as the test instruments and methods are described. The results of experimental study determining the efficiency of a spherical roller transmission depending on the torque being transmitted and the rotational speed of the drive shaft are presented. It has been found that the mean efficiency of the speed reducer is within the range of 0.7 … 0.8 and its maximum value is 0.81, which corresponds to the efficiency of worm gears with similar characteristics. The theoretical calculations for determining the efficiency, which were obtained in previous studies, have been confirmed; the value of the reduced friction coefficient has been calculated. The constancy of the efficiency and the reduction ratio of the experimental model of the speed reducer and the factors influencing this constancy have been investigated.
Surface treatment by combined processes of cutting and magnetodynamic rolling
Authors: Svirepa D M , Kruchynina A S
Published: March 2021

Technologies for mechanical treatment of the inner cylindrical surface of parts using combination tools have a number of advantages over traditional methods. The combination of two technological processes in one operation (cutting and magnetodynamic rolling) leads to increased production efficiency, reduced cost of parts manufacturing and improved quality characteristics of the machined surface. The developed designs of tools for combined treatment with various magnetic modules (with radial and axial arrangement of the magnetic system) have a number of specific features and advantages, which makes it possible to expand the field of application of the combination tools.
Cold deformation of non-circular drill pipes
Authors: Parshin S V , Dronov A I
Published: March 2021

In this paper, the pipe billet dimensions are determined according to the required kelly configuration. A finite element model of the deformation center at drawing junctions is created. Based on the stress-strain calculations, the following invariants are determined: hydrostatic pressure, load, and degree of shear strain. The metal damage extent is determined and proved to be reducible by performing the two-pass drawing. It is shown that the ‘pendulum’ heat treatment provides for complete healing of the metal defects caused by plastic deformation. As a result, a technology of producing high quality kellies is proposed.
iLabit Robotica: A Photo-Realistic Extension for Robotics Toolbox
Authors: Kholodilin Ivan , Savosteenko Nikita , Abramov Yuri , Lago Luis A
Published: March 2021

This paper presents a photo-realistic extension for Robotics Toolbox (iLabit Robotica). Built using Unity, the proposed simulator integrates the 6-axis robot arm, sensors, and elements for interactions. iLabit Robotica is aimed to increase the quality of the engineering education and motivation of students towards the educational process, by providing a new beginning for the project-based learning (PBL) approach with the aid of virtual technologies. We strongly believe that by simulating real technological processes and integrating them into the educational process, students will not only achieve a valuable practical experience by solving “real-life” existing problems, but also a substantial interest towards the subject. We demonstrate the compatibility between our simulator and Robotics Toolbox by interacting with objects placed inside the virtual environment through Matlab via TCP/IP. Experiments demonstrate that the operating process is simple and it provides robust results and a higher measurement accuracy. The proposed simulator and supporting materials are available online: http://www.ilabit.org.
Studying Interaction of Multi-Motor Forming System for Double Curvature Items
Authors: Deryuzhkova N E , Solovyev V A , Teterin V V
Published: March 2021

Large double curvature panels are widely used in manufacture of modern aircraft bodies. One of the possible ways to manufacture such parts is to form a workpiece using the method of high temperature multi-point forming by means of a set of moving cores. The paper considers workpiece forming process using different core unit configurations and presents the results of workpiece behaviour study during forming, obtained by means of a finite element method. Conclusions are made on the existing interconnections between forming cores during the forming process.
The design of a support chair for more effective patient rehabilitation
Authors: Mamontov G , Seryakov V , Khmelevsky Y , Tkacheva L
Published: March 2021

The authors examined the effect of different color shades on a person and found an effective color and shape solution that can improve the quality of rehabilitation equipment. The paper presents a survey of colors and shapes visual perception by human. As result of theoretical and experimental research, the rehabilitation support chair was designed as a cube-shaped structure with elements painted in shades of dark blue, yellow and white.
Quality Ratios for Public Transport Services
Authors: Novikov A N , Eremin S V , Shevtsova A G , Lomakin D O , Kulev A V
Published: March 2021

The system of quality indicators used for public transportation is proposed by the authors. Additionally, the paper considers the necessity to develop an assessment ratio, which defines a competitiveness level among enterprises. To assess the activities of a transport operator, the authors proposed to apply a four-level system that will assess the quality of transportation: the level of service may be “excellent”, “good”, “satisfactory” and “unacceptable”.
A device for automatic feeding of coated electrodes into a weld pool
Authors: Gordynets A S , Nepomnyashiy A S
Published: March 2021

The paper presents the specification of a device for automatic feeding of coated electrodes into a weld pool and the results of its application. It eliminates subjective assessment methods and professional skills of welders, which contributes to a more stable metal transfer into the weld pool. The research results have shown that automatic feeding of coated electrodes into a weld pool enables to reasonably assess their welding and technological properties. Any devices similar to the developed one and the results of their tests have not been found.
Determination of Optimal Frequency to Replace Cutting Elements in Chain Trenchers
Authors: Kravchenko S M , Slepchenko V A , Slepchenko I V
Published: March 2021

The article deals with some factors influencing the wear resistance of cutting elements in chain trenchers. It provides a number of recommendations to ensure most cost-effective operations with cutting tools in chain trenchers.
Flexural properties of copper-filled carbon fiber reinforced polymers
Authors: Eremin A V , Burkov A V
Published: March 2021

The paper demonstrates the results of flexural tests of carbon fiber reinforced polymers with the addition of copper microfillers with content varying from 2.5 to 10 wt%. It is shown that the implemented dispersive reinforcement leads to the increase of flexural strength on composites by 9%, while the elastic modulus remains the same. The reasons for the advancement in mechanical properties are discussed.
Sex-specific contributions to nest building in birds
Authors: Mainwaring Mark C , Nagy Jenő , Hauber Mark E
Published: March 2021

The causes and consequences of interspecific variation in sex-specific contributions to animal parental care are relatively well understood during pregnancy or incubation and during offspring provisioning, but comparative patterns of sex-biased investment during nest-, den-, or other shelter-building have been almost completely overlooked. This is surprising because birthing shelters’ protective properties have important fitness consequences for both parents and offspring. Here, we address this gap in our knowledge by testing predictions concerning sex-specific contributions to avian nest building in more than 500 species of Western Palearctic birds in relation to the time available to breed and sex-specific reproductive effort, while also examining correlates with nesting site and nest structure. Using multivariate phylogenetic comparative and path analysis approaches, we found that, opposite to what had been predicted, species in which females build nests alone have shorter breeding seasons and breed at higher latitudes. In addition, species in which females lay larger clutch sizes and incubate eggs alone are more likely to have nests built by females alone, again countering predictions that reproductive contributions are not traded-off between the sexes. Finally, however, sex-specific nest building contributions were predictably related to nest site and structure, as species in which females built nests alone were more likely to have open cup nests relative to enclosed, domed nests of species in which both parents build. Our study provides important new insights, and generates several new questions for experimental research into the adaptive dynamics of sex-specific contributions prior or at the onset of parental care.
muCNV: genotyping structural variants for population-level sequencing
Authors: Jun Goo , Sedlazeck Fritz , Zhu Qihui , English Adam , Metcalf Ginger , Kang Hyun Min ,   Human Genome Structural Variation Consortium (HGSVC), Lee Charles , Gibbs Richard , Boerwinkle Eric
Published: March 2021

Motivation

There are high demands for joint genotyping of structural variations with short-read sequencing, but efficient and accurate genotyping in population scale is a challenging task.

Results

We developed muCNV that aggregates per-sample summary pileups for joint genotyping of >100 000 samples. Pilot results show very low Mendelian inconsistencies. Applications to large-scale projects in cloud show the computational efficiencies of muCNV genotyping pipeline.

Availabilityand implementation

muCNV is publicly available for download at: https://github.com/gjun/muCNV.

Supplementary information

Supplementary data are available at Bioinformatics online.
Quantification of cell behaviors and computational modeling show that cell directional behaviors drive zebrafish pectoral fin morphogenesis
Authors: Dokmegang Joel , Nguyen Hanh , Kardash Elena , Savy Thierry , Cavaliere Matteo , Peyriéras Nadine , Doursat René
Published: March 2021

Motivation

Understanding the mechanisms by which the zebrafish pectoral fin develops is expected to produce insights on how vertebrate limbs grow from a 2D cell layer to a 3D structure. Two mechanisms have been proposed to drive limb morphogenesis in tetrapods: a growth-based morphogenesis with a higher proliferation rate at the distal tip of the limb bud than at the proximal side, and directed cell behaviors that include elongation, division and migration in a non-random manner. Based on quantitative experimental biological data at the level of individual cells in the whole developing organ, we test the conditions for the dynamics of pectoral fin early morphogenesis.

Results

We found that during the development of the zebrafish pectoral fin, cells have a preferential elongation axis that gradually aligns along the proximodistal (PD) axis of the organ. Based on these quantitative observations, we build a center-based cell model enhanced with a polarity term and cell proliferation to simulate fin growth. Our simulations resulted in 3D fins similar in shape to the observed ones, suggesting that the existence of a preferential axis of cell polarization is essential to drive fin morphogenesis in zebrafish, as observed in the development of limbs in the mouse, but distal tip-based expansion is not.

Availabilityand implementation

Upon publication, biological data will be available at http://bioemergences.eu/modelingFin, and source code at https://github.com/guijoe/MaSoFin.

Supplementary information

Supplementary data are available at Bioinformatics online.
Kcnq2/Kv7.2 controls the threshold and bi-hemispheric symmetry of cortical spreading depolarization
Authors: Aiba Isamu , Noebels Jeffrey L
Published: March 2021

Spreading depolarization is a slowly propagating wave of massive cellular depolarization associated with acute brain injury and migraine aura. Genetic studies link depolarizing molecular defects in Ca2+ flux, Na+ current in interneurons, and glial Na+-K+ ATPase with spreading depolarization susceptibility, emphasizing the important roles of synaptic activity and extracellular ionic homeostasis in determining spreading depolarization threshold. In contrast, although gene mutations in voltage-gated potassium ion channels that shape intrinsic membrane excitability are frequently associated with epilepsy susceptibility, it is not known whether epileptogenic mutations that regulate membrane repolarization also modify spreading depolarization threshold and propagation. Here we report that the Kcnq2/Kv7.2 potassium channel subunit, frequently mutated in developmental epilepsy, is a spreading depolarization modulatory gene with significant control over the seizure-spreading depolarization transition threshold, bi-hemispheric cortical expression, and diurnal temporal susceptibility. Chronic DC-band cortical EEG recording from behaving conditional Kcnq2 deletion mice (Emx1cre/+::Kcnq2flox/flox) revealed spontaneous cortical seizures and spreading depolarization. In contrast to the related potassium channel deficient model, Kv1.1-KO mice, spontaneous cortical spreading depolarizations in Kcnq2 cKO mice are tightly coupled to the terminal phase of seizures, arise bilaterally, and are observed predominantly during the dark phase. Administration of the non-selective Kv7.2 inhibitor XE991 to Kv1.1-KO mice partly reproduced the Kcnq2 cKO-like spreading depolarization phenotype (tight seizure coupling and bilateral symmetry) in these mice, indicating that Kv7.2 currents can directly and actively modulate spreading depolarization properties. In vitro brain slice studies confirmed that Kcnq2/Kv7.2 depletion or pharmacological inhibition intrinsically lowers the cortical spreading depolarization threshold, whereas pharmacological Kv7.2 activators elevate the threshold to multiple depolarizing and hypometabolic spreading depolarization triggers. Together these results identify Kcnq2/Kv7.2 as a distinctive spreading depolarization regulatory gene, and point to spreading depolarization as a potentially significant pathophysiological component of KCNQ2-linked epileptic encephalopathy syndromes. Our results also implicate KCNQ2/Kv7.2 channel activation as a potential adjunctive therapeutic target to inhibit spreading depolarization incidence.
The Essential Role of Data and Safety Monitoring Boards (DSMBs) in Ensuring the Ethics of Global Vaccine Trials to Address Coronavirus Disease 2019 (COVID-19O)
Authors: Eckstein Lisa , Rid Annette , Kamuya Dorcas , Shah Seema K
Published: March 2021

Coronavirus disease 2019 (COVID-19) vaccines are being developed and implemented with unprecedented speed. Accordingly, trials considered ethical at their inception may quickly become concerning. We provide recommendations for Data and Safety Monitoring Boards (DSMBs) on monitoring the ethical acceptability of COVID-19 vaccine trials, focusing on placebo-controlled trials in low- and middle-income countries.