bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental and theoretical studies of the effect of long-term natural aging on the mechanical properties of high impact polystyrene
Authors: Arutyunyan A R 
Published: April 2020

Abstract
Effect of prolonged natural aging in the laboratory conditions at room temperature during 40 years on the mechanical properties of six different marks of high impact polystyrene (HIPS) was investigated. The deformation curves in tensile experiments were obtained. These curves indicated that the hardening effect is observed for all marks of HIPS after aging. The HIPS were also tested for creep at room temperature and constant tensile force. Specimens of most marks of HIPS does not fractured during 30 days. After natural aging during 40 years, the specimens were fractured in a time-to-fracture range from 10 minutes to 30 hours depending on the mark of HIPS. A modified version of the Maxwell equation written in the effective time scale is used to describe the obtained experimental creep curves. A good agreement between theoretical and experimental creep curves is observed.
Deformability during short-term loading, shrinkage and creep of a cementitious soil composite on the basis of belozems of carbonate
Authors: Karapetyan K A , Hairoyan S H , Manukyan E S 
Published: April 2020

Abstract
The results of short-term (strength, tangent modulus and transversal deformation coefficient) and long-term (shrinkage and creepage deformations) experimental research of cylindrical test pieces manufactured from the cementitious soil of carbonate composition are considered. The obtained experimental data are compared with similar data defined for the light-weight concrete based on lithoid-pumice.
Numerical analytic method for solving the inverse coefficient problem of heat conduction in anisotropic half-space
Authors: Kolesnik S A , Bulychev N A 
Published: April 2020

Abstract
The paper proposes a numerical-analytical method for solving the inverse problem of identification of the components of the thermal conductivity tensor in anisotropic materials on the basis of the earlier analytical solution of the heat conduction problem in anisotropic half-space when heated with a thermal flow. The method is based upon expansion of the residual functional into Taylor series and determination of incremental vectors of the target coefficients which are then used for application of iterative gradient descent algorithms. The solution demonstrates fine iteration convergence even if the initial approximation of the coefficients vector differs from the target one by several times, and even when there is some inaccuracy in the experimental data. The proposed method can be used for a wide range of problems in continuum mechanics.
On the classification of boundary value problems for elastic homogeneous and piecewise homogeneous spaces with a penny-shaped crack
Authors: Mkhitaryan S M , Mkrtchyan M S , Kanetsyan E G 
Published: April 2020

Abstract
The classification of the basic axisymmetric boundary value problems of the mathematical theory of elasticity for homogeneous and piecewise homogeneous elastic spaces with a penny-shaped crack is given. Using the Hankel integral transform, governing integral equations (GIEs) of these problems are derived and methods for finding their exact solutions are indicated.
Pressure calculation using obstacle problem for CMP modeling
Authors: Piliposyan D , Ghulghazaryan R , Poghosyan M , Nersisyan H 
Published: April 2020

Abstract
Chemical mechanical polishing/planarization (CMP) is one of the most important fabrication technologies in the semiconductor industry. CMP is used to achieve planar surfaces and remove excess deposited material from the wafer. During CMP, a chemical “slurry” containing abrasive particles and chemical reagents is deposited on the polishing pad. The polishing pad is then pressed against the rotating wafer. The combined action of the polishing pad and chemical slurry results in material removal and planarization of the wafer surface. Modeling of the CMP process allows detection of potential planarization defects in chips before manufacturing. Accurate computation of pressure distribution across the wafer surface is crucial for accurate modeling of the CMP process. The pressure distribution calculation is usually done using the Hertz contact theory and Chekina model, which involves computations of direct and inverse fast Fourier transforms (FFT and IFFT) and pad displacements updates. In this paper, we adopted an obstacle problem approach for calculating the pressure distribution across the wafer/die surface for CMP modeling. In an obstacle problem, the pad is assumed to be an elastic membrane with fixed boundaries that is displaced by the wafer surface. The goal is to find the equilibrium position for the pad and calculate the pressure distribution over the surface in contact. The main advantage of this approach is that computations of FFT and IFFT and recalculations of the pad displacements can be avoided. This can lead to a more accurate model that is independent of pad displacement update method. The approach is tested on several examples. The results show correct physical behaviour and are in agreement with expectations.
The uni-axial tensile response of titanium-based fiber metal laminates
Authors: Sharma A P , Velmurugan R 
Published: April 2020

Abstract
Fiber metal laminates (FMLs) consist of thin layers of metal bonded together with layers of composite based on fiber reinforcement. In the present study, titanium sheets (Ti-6Al-4V) having thicknesses of 0.2 mm, 0.4 mm, and 0.6 mm and glass-fiber reinforced composite layers having uni-directional layup are considered to fabricate FMLs and response of these laminates are evaluated under tension. The consideration for four discrete sequences of stacks is made for FMLs preserving thickness of a total layer of metal same and these laminates are fabricated using a method of hand layup. The elastic modulus, yield strength and ultimate strength of FMLs are theoretically predicted by rule of mixtures (ROM). The layup’s sequence does not affect initial modulus of FMLs subjected to tension. Whereas, the ultimate strength and FMLs’ behavior succeeding ultimate strength are significantly affected by layup’s sequence. The properties of a laminate obtained from experiment and predicted from ROM are found in good agreement with each other.
Vibration isolation of rolling bearings in electric machines
Authors: Shekyan H G , Gevorgyan A V 
Published: April 2020

Abstract
In the paper forced vibrations of high-speed electric machines with rotors on the rolling bearings are considered. It is shown that in high-speed rotor machines the vibration loadings, which bring to overstrain of contact surfaces of the rolling and violation of the bearings work regime, are one of the main reasons of the bearings failure.
A comparative analysis of wave properties of the finite and infinite doubly periodic arrays of volumetric and thin defects
Authors: Sumbatyan M A , Remizov M Yu 
Published: April 2020

Abstract
A two-dimensional problem on wave propagation through doubly periodic arrays of defects located in an elastic material is studied. The incident wave is longitudinal and the defects may be thin (cracks) or volumetric (voids). For both the types of defects the main aim is to compare the wave properties of the structure whose geometry may be either finite or infinite in the transversal periodic direction with respect to the direction of the incident wave. The physical parameters under consideration are the reflection and the transmission coefficients, which are studied versus frequency parameter in the one-mode regime.
Sliding contact of coated viscoelastic solids: model and experiment
Authors: Torskaya E V , Stepanov F I , Tsukanov I Yu , Shkalei I V 
Published: April 2020

Abstract
Sliding of a smooth indenter over a viscoelastic half-space with a rigid coating is considered. a Quasistatic contact problem is formulated, and a numerical-analytical solution method using the boundary element method and iterative procedure is developed. The dependence of the distribution of contact pressure and dissipative losses on the sliding velocity, coating thickness is analyzed. Friction of polyurethane materials (with rheological properties) coated by relatively hard carbon-based material is studied experimentally. Calculation results and experimental data have good qualitative correlation.
CFD Simulation on the Natural Ventilation and Building Thermal Performance
Authors: Widiastuti R , Hasan M I , Bramiana C N , Pramesti P U 
Published: April 2020

Abstract
The types of window, either permanent or impermanent will influence the building thermal profiles. Natural ventilation is one of technique to create passive cooling design in the building. It can improve the quality of indoor air, thermal comfort and reduction of energy consumption for air conditioning. In this present work, a study on the type of natural ventilation and the effect to thermal building performance was conducted. There are two types of natural ventilation as main variable in this study, top hung window and jalousie window. To develop the study, a simulation used Computational Fluid Dynamics (CFD) also conducted. One natural ventilation as outlet also added in the simulation. Based on the data measurement and computer simulation, jalousie window can provide better thermal performance. The range of difference between indoor air temperature on the chamber with jalousie window and chamber with top hung window is 0.2°C to 0.5°C, showing greater heat loss. The average of amount on the indoor air flow also was found 0.0317 m/s higher in the chamber with jalousie window. Particularly in the inlet, it was clear that the velocity of incoming air flow is faster and significantly allowed greater air with lower temperature entered from outside to inside.
Lighting System Energy Conservation Simulation at Faculty of Engineering Diponegoro University Library Using Ecotect
Authors: Wijayanti R W , Prianto E , Windarta J 
Published: April 2020

Abstract
Global warming is becoming a severe concern day by day. Indonesia still uses a large portion of fossil fuels in electricity generation; this made matters even worse due to carbon emissions. Government through PP No. 70 of 2009 issued an energy conservation policy stating that used energy must be carried out economically and efficiently. The objective of this policy for all sectors of life, one of sector is the academic environment. The library spends a lot of energy consumption for supporting activities, especially in the lighting system. Observations and measurements were performed to see the illuminance of the library when categorized as visually very bright. The results are then compared with the standard, whether it meets the minimum threshold or not or even exceed, and how the savings opportunities that can be done. The method that used in this research is data collection, measurement of illuminance, and search for savings opportunities through simulations. Based on methods, a savings opportunity is obtained by reducing the number of lamps used. If this step is applied, then obtained savings of up to 514 kWh/year, equivalent to the electricity bill amounting to IDR 462.672, - from the lighting system.
Taperless Type Blade Design with Naca 5513 Airfoil for Wind Turbine 500 TSD
Authors: Yohana E , Sinaga N , Haryanto I , Taufik V R I , Dharmawan E 
Published: April 2020

Abstract
The utilisation of wind energy in Indonesia is still low because the average wind speed in Indonesia is low. The design of the HAWT using a NACA airfoil which has a high C/Cd value and produces 500 W of power at wind speeds of 1 m/s up to 11 m/s. The research was conducted in 3 stages. First, the calculation stage to determine the radius, chord and twist of the blade. Second, the initial design stage of the blades is simulated to determine the NACA airfoil that is used and to know the coefficient of performance and power produced. Third, the stage of designing the 3D blade design. The design results show that the HAWT blades with NACA 5513 airfoil taperless type with the radius of 0.9 m on the airfoil simulation produced a higher Cl/Cd value with 152.73 when α = 4 °. In the Cp simulation for TSR, the Cp value reaches 20% in TSR 2 up to 10. Meanwhile, in the power wind speed (P - v) simulation, the power generated reaches 500 W at wind speeds of 11 m/s and angular velocity 263 up to 1000 rpm.
The Effectiveness of Biogas Method from Rice Husks Waste: Liquid Anaerobic Digestion and Solid-State Anaerobic Digestion
Authors: Syafrudin S , Nugraha W D , Matin H H A , Saputri E S , Budiyono B 
Published: April 2020

Abstract
Liquid Anaerobic digestion (L-AD) generally was operated in the total solid between 0 until 15%, while the Solid- State Anaerobic Digestion (SS-AD) operated at total solid higher than 15%. In this research, waste of rice husk were evaluated to determine the effect of biogas production of Liquid Anaerobic Digestion (L-AD) and Solid-State Anaerobic Digestion (SS-AD). This experiment was operated in batch system in the laboratory scale of anaerobic digestions and at room temperature, with C/N ratio was set at 25oC. Total solids (TS) was varied from 5, 7, 9, 19, 21 and 23%. Pretreatment of rice husk was needed to lower the high lignin content in the material, with added sodium hydroxide (NaOH). Biogas produced was measured by using the method of water transfer every two days for 60 days. The results showed the chemical pretreatment of sodium hydroxide increase the production of biogas, with the highest yield biogas difference between LAD condition and SS-AD by 14%. The highest yield biogas production in rice husk was obtained at TS 19%, with a productivity volume of 935.5 ml. Specific biogas production in TS 5, 7, 9, 19, 21 and 23% was 57; 56.64; 45.36; 24.62; 15.15; and 12.45 ml/g TS. The concentration of total solid to L-AD higher than SS-AD conditions. Further research needs to be studied is to optimize the yield of biogas with SS-AD system.
Carbon Footprint of Academic Activities: A Case Study in Diponegoro University
Authors: Syafrudin S , Zaman B , Budihardjo M A , Yumaroh S , Gita D I , Lantip D S 
Published: April 2020

Abstract
Carbon emissions are a significant cause of climate change. As an effort to reduce emissions in the university environment, carbon footprints at Diponegoro University (Undip) need to be calculated to find out how much campus activity contributes to the emissions produced and analyze scenarios that can be applied in minimizing them. The carbon footprint study at Undip was carried out in 3 scopes according to The Greenhouse Gas Protocol. Scope one covers clean water treatment activities. Scope two covers electricity usage activities, while scope three covers transportation, wastewater, and solid waste treatment activities in the campus environment. Carbon footprint emissions from the three scopes are calculated based on methods from the International Panel on Climate Change (IPCC). Emissions calculated are CO2, CH4, and N2O expressed in TonCO2-eq. The carbon footprint resulting from campus activities at Undip is 16, 345.83 TonCO2-eq. The first and second-largest carbon footprint contributors came from electricity and transportation activities with a total carbon footprint of 13, 953.22 TonCO2-eq and 1, 449.99465 TonCO2-eq, respectively. The emission reduction business strategies that can be carried out are through conservation and energy efficiency approaches as well as the use of Campus Buses and increasing the number of green space.
Quantifying Carbon Footprint of Diponegoro University: Non-Academic Sector
Authors: Budihardjo M A , Syafrudin S , Putri S A , Prinaningrum A D , Willentiana K A 
Published: April 2020

Abstract
This study focuses on quantifying the carbon footprint generated by non-academic activities at Diponegoro University, Indonesia. The carbon footprint study at Diponegoro University divides into three scopes, which are emissions from sources that are owned or controlled directly by the university, indirect emissions from electricity consumption, and other indirect emissions. Scope one covers clean water treatment, scope two includes electricity usage, while scope three involves wastewater and waste disposal in the campus area as a result of non-academic activities. The calculated emissions include CO2, CH4 and N2O expressed in TonCO2-eq. The carbon footprint resulting from non-academic activities at Undip is 13, 945.55 TonCO2-eq. The most significant carbon footprint contributors comes from electricity activities with a total carbon footprint of 13, 857.798 TonCO2-eq, followed by wastewater and water supply activities.
Relationship of Environmental ability and economic ability company: Evidence from Indonesia
Authors: Nasution A A , Risanty R , Erwin K , Nasution F N 
Published: April 2020

Abstract
Environmental performance is strongly influenced by the extent of impetus towards environmental management carried out by various agencies, especially agencies government. Environmental performance will also be achieved at a high level if the company proactively undertakes various environmental management actions in a controlled manner. The purpose of this study is to examine the effect of performance environment on economic performance. Data were analyzed using regression multiple. The data used in this study comes from annual reports registered on the Indonesia Stock Exchange and PROPER in 2016-2018. Results this research shows that environmental performance has a significant effect on economic performance. The company is expected to pay attention to the completeness of the disclosure items environmental performance that needs to be disclosed in a sustainable report. This will certainly make it easier for investors to assess the company’s performance. In besides that there needs to be more binding regulations from the government regarding ongoing reports made by the company so that the company can know more clearly about what information should be disclosed in ongoing report.
The Effect of Giving Avocados (Persea americana Mill) and Guava (Psidium guajava Linn) on Hemoglobin Levels in Traditional Rice Farmers
Authors: Utari R , Setyaningsih Y , Suwondo A 
Published: April 2020

Abstract
Data of Puskesmas (Public Health Center) profile was obtained from Hiang Lestari village midwife, showed that 38% of rice farmers develop anemia. The objective of research was to find out the effect of Avocado (Persea americana mill) and Guava (Psidium guajava linn) administration on Hemoglobin level in Traditional Rice Farmers in Hiang Lestari village. This study was a quasi-experiment research with Pretest-Posttest with control group design. The population of research was all traditional female farmers fulfilling the inclusion criteria. The sample consisted of 30 persons, taken using purposive sampling, divided into 3 treatment groups: avocado, guava, and combined avocado and guava consumption. Analysis was conducted using T Paired Sample Test. The result of research showed that there was a difference of hemoglobin level with sig. value (2-tailed) of 0.000 < 0.05 having treated with avocado fruit consumption, with average hemoglobin level increase of 1.3 g/dl, with sig. value (2-tailed) of 0.002 < 0.05 having treated with guava fruit consumption, with average hemoglobin level increase of 1.6 g/dl, and with sig. value (2-tailed) of 0.000 < 0.05 having treated with combined avocado and guava fruit consumption, with average hemoglobin level increase of 2.8 g/dl.
Batik Pemalang Organic Wastewater Composition and Simple Electrocoagulation-Filtration Treatment
Authors: Pratiwi N I , Sari S R , Arifan F , Wulandari A T , Alkian I , Mustasjar B , Aji M B F B 
Published: April 2020

Abstract
Wastewater produced by batik industry in Cibelok Village, Pemalang that is disposed straight into the sewage will increase the concentration of Biochemical Oxygen Demand (BOD), ammonia (NH3), Chemical Oxygen Demand (COD), chromium (Cr), lead (Pb), watercolour, acidity (pH), and dissolved oxygen (DO). Disposed batik wastewater without treatment will contaminate the environment, mainly its water and soil. The main purpose of this research is to reduce the concentration of Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), ammonia (NH3), chromium (Cr), lead (Pb), watercolour, acidity, and dissolved oxygen (DO) by treating batik Cibelok’s waste and not contaminate the surrounding environment. Laboratory test results on batik waste in COD, BOD, DO, ammonia, chromium, lead, colour, and acidity (pH). These results are not in accordance with the 2014 Waste Water Quality Standard Number 5 by the Regulation of the Minister of Environment of the Republic of Indonesia. Alternatives that have been done to treat Cibelok Village’s batik waste is to lower dangerous substances concentration through electrocoagulation and filtration. The processes could lower COD level around 57.6%, ammonia 98%, chromium 85%, and BOD 67%. Reducing the concentration of the substance makes the batik waste safer and environmentally friendly when it’s finally disposed to the sewage.
Potential of Water Pollution in Girimulyo, West Progo
Authors: T Listyani R A , Peni S N 
Published: April 2020

Abstract
Hydrogeological survey activities have been carried out to identify potential water pollution in the Girimulyo area, West Progo. The research method was conducted with a field hydrogeological survey to get hydrogeological data and water quality in the form of pH and TDS. Water quality status evaluation is to determine the pollution index based on water quality standards. The results showed that the water in the study area was generally colorless, tasteless, and odorless and transparent (not turbid). The pH value of water measured in the field is 7 - 8.1, while the TDS is 15 - 305 ppm. The results of the water chemistry laboratory test show that groundwater quality is quite good with a pH of 7 - 8.1 and TDS 112-240 ppm. Groundwater violence is in the middle to medium class - hard, as is river water. Chemical types develop as groundwater Ca - bicarbonate and Ca, Mg - bicarbonate. The index of water pollution studied is in the mildly polluted category (Pollution Index of 1, 81 – 4, 81), with the highest level of pollution found in river water is in Niten.
Crackers from Fresh Water Snail (Pila ampullacea) Waste as Alternative Nutritious Food
Authors: Broto R T D W , Arifan F , Setyati W A , Eldiarosa K , Zein A R 
Published: April 2020

Abstract
Fresh water snail (Pila ampullacea) is large fresh water snail that can be found in rice fields, ponds, lakes and marshes. Most of them live in paddy fields and become pests for its plant thus the farmer tries to eradicate. Whereas, aquatic animals especially snail contain high level of protein with an amino acid profile similar with the meat land animals, thus making it beneficial to health in countries where snail exists. Thus, fresh water snail can be used as a raw material in producing foods or snacks, one of the famous snack in Southeast Asian countries is cracker. Pila ampullacea was obtained from the swamp and was cleaned it up by removed the flesh from its shell and used the water then production of the crackers. Nutrition contents of the fresh water snail cracker is protein (10.67%) and lipid (0.06%). The organoleptic analysis of crispiness was shown good result with mean score is 4.1.