bluuebunny/crossref_metadata_2025 huggingface dataset:
Livestock Feed Production from Sago Solid Waste by Pretreatment and Anaerobic Fermentation Process
Authors: Sumardiono Siswo , Dwi W N Aditya , Rahman A Farel , Pudjihastuti Isti
Published: March 2018

Food needs in Indonesia is increasing, including beef. Today, Indonesia has problem to do self-sufficiency in beef. The cause of the problem is the quality of local beef is still lower compared with imported beef due to the quality of livestock feed consumed. To increase the quality of livestock is through pretreatment and fermentation. Source of livestock feed that processed is solid sago waste (Arenga microcarpa), because in Indonesia that is relatively abundant and not used optimally. Chemical pretreatment process for delignification is by using NaOH solution. The purposes of this research are to study NaOH pretreatment, the addition of Trichoderma sp, and fermentation time to improve the quality of sago solid waste as livestock feed through anaerobic fermentation. The variables used are addition or without addition (4%w NaOH solution and Trichoderma sp 1%w) and fermentation time (7, 14 and 21 days), with the response of crude fiber and protein. The result of this research shows that the pretreatment with soaking of NaOH solution, addition of Trichoderma sp and 14 days of fermentation was more effective to improve the quality of solid sago waste with decrease of crude fiber from 33.37% to 17.36% and increase of crude protein from 4.00% to 7.96%.
Extraction of Phytochemical Compounds from Eucheuma cottonii and Gracilaria sp using Supercritical CO2 Followed by Subcritical Water
Authors: Setyorini Dwi , Aanisah Ridlo , Machmudah Siti , Winardi Sugeng , Wahyudiono  , Kanda Hideki , Goto Motonobu
Published: March 2018

Extraction of phytochemical compounds (such as β-carotene, linoleic acids, carrageenan, and polyphenols) from algae Eucheuma cottonii and Gracilaria sp with supercritical CO2 followed by subcritical water has been investigated. Supercritical CO2 extraction was carried out at pressure of 25 MPa, temperature of 60°C, CO2 flowrate of 15 ml/min, and ethanol flowrate of 0.25 ml/min. To determine the content of carotenoids and linoleic acids, the extracted compounds were analyzed using a spectrophotometer UV-Vis. The residue of algae starting material was subsequently extracted by subcritical water at pressures of 3, 5, and 7 MPa, and temperatures of 120, 140, 160, and 180 °C. Carrageenan extracted by subcritical water was analyzed using Fourier Transform Infra Red (FTIR), while the total phenolic compound was analyzed with UV-vis spectrophotometer. Moreover, the antioxidant efficiency of extract was also examined by DPPH assay method. Based on the analytical result, β-carotene and linoleic acid content in Eucheuma cottonii were 209.91 and 321.025 μg/g sample, respectively. While β-carotene and linoleic acid content in Gracilaria sp were 219.99 and 286.52 μg/g sample, respectively. The optimum condition of subcritical water extraction was at 180°C and 7 MPa. At this condition, the highest TPC content in the extract from Eucheuma cottonii and Gracilaria sp were 18.51 mg GAE/g sample and 22.47 mg GAE/g sample, respectively; while the highest yield of carrageenan extracted from Eucheuma cottonii and Gracilaria sp were 61.33 and 65.54 g/100 g dried algae, respectively. At the same condition, the antioxidant efficiency was 0.513 min-1 for Eucheuma cottonii and 0,277 min-1 for Gracilaria sp. Based on the results the extraction method effectively separated non-polar and polar compounds, then increased the antioxidant efficiency of extract.
Production of Biogas from Organic Fruit Waste in Anaerobic Digester using Ruminant as The Inoculum
Authors: Budiyono  , Manthia Firliani , Amalin Nadya , Hawali Abdul Matin Hashfi , Sumardiono Siswo
Published: March 2018

Organic waste, fruit waste and vegetable waste are the best substrate to produce biogas. Waste management system for producing biogas can be used as a solution with the waste problem by converting the wastes into biogas. This study is expected to review of the effect of substrate type and substrate composition for the volume of biogas produced. In this study, materials consist of fruit wastes (oranges, apples, papayas, and tomatoes), cow ruminant, urea, cow dung, Na2CO3 buffer, NH4HCO3 buffer, and distilled water with variations of the substrate materials, F/ W, and the buffer types. The addition of cow manure and Na2CO3 buffer with 1:2 of F/W, production of biogas is greater than variable which is used NH4HCO3 buffer and without the addition of cow dung. Variables with addition of cow dung with 1:1 of F/W and using Na2CO3 buffer, the result is greater than the variable using the same buffer but without the addition of cow dung and variables with 1:1 of F/W with the addition of cow dung and Na2CO3 buffer and variables with the same feed and without the addition of cow dung produce more biogases than variable which is the using NH4HCO3 buffer, 1:1 of F/W and without the addition of cow dung.
Utilization of Delignified Sawdust as Raw Material of Biogas Production
Authors: Zumalla Asfarina , Budiyono  , Sumardiono Siswo
Published: March 2018

Biogas is one alternative to replace the irreplaceable energy source that has begun to diminish its existence. The raw materials for biogas manufacture are renewable biomass, usually using plantation waste, agriculture, and livestock. Using biogas can also reduce environmental pollution. One of the agricultural waste that has great potential to become the raw material of biogas is teak sawdust. Wood processing industry in Indonesia quite a lot, but wood has a high lignosesluosa content, so it needs the right method to process it. With the delignification of lignin levels on teak sawdust will decrease. Wood sawdust is soaked using NaOH for 1, 2, 3, and 4 days with 4% w / v concentration. The lowest lignin and hemicellulose content was 25.79% and 87.9% in pretreatment for 4 days, while the highest cellulose level was 57, 34%. The accumulated volume of biogas at 1 day pretreatment, ie 709 ml / g TS. Gcms shows the enlarged peak area of methanamine, N-methyl from before pretreatment. The fastest biogas formation (λ) in 4 days pretreatment, 1.60403 days and the largest constant A and U variables at 1 day were 914.5903 ml / g TS and 34.59765 ml / g TS.
Kaolin as a Source of Silica and Alumina For Synthesis of Zeolite Y and Amorphous Silica Alumina
Authors: Sri Rahayu Endang , Subiyanto Gatot , Imanuddin Arief , Wiranto  , Nadina Sabrina , Ristiani Rista , Suhermina  , Yuniarti Endang
Published: March 2018

Kaolin is the clay mineral which containing silica (SiO2) and alumina (Al2O3) in a high percentage, that can be used as a nutrient in the synthesis of zeolites and amorphous silica alumina (ASA). The objective of this research is to convert the Belitung kaolin into silica and alumina as nutrients for the synthesis of zeolites and amorphous silica alumina, which are required in the preparation of the catalysts. Silica and alumina contained in the kaolin were separated by leaching the active kaolin called as metakaolin, using HCL solution, giving a solid phase rich silica and a liquid phase rich alumina. The solid phase rich silica was synthesized to zeolite Y by adding seed of the Y Lynde type, through the hydrothermal process with an alkaline condition. While, the liquid phase rich alumina was converted into an amorphous silica alumina through a co precipitation method. Characterization of zeolite and ASA were done using XRD, surface area and pore analyzer and SEM. The higher of alumina in liquid phase as a result of the rising molar of HCL in the leaching process was observed, but it didn’t work for its rising time. Products of ASA and zeolite Y were obtained by using liquid phase rich alumina and solid phase rich silica, respectively, which resulted through leaching metakaolin in 2.5 M HCl at temperature of 100° C for 2 hours.
Synthesis and Characterization of Non-Halogenic Fire Retardant Composite with Epoxy Resin and Additive Combination Al(OH)3/Mg(OH)2
Authors: Handaya Saputra Asep , Fathurrahman Farhan
Published: March 2018

Epoxy has many advantages over other resin. However, in certain usage, additive is needed to raise the thermal resistance of the composites, while lowering its negative effect on health and environment. One of the most common additives used for thermal resistance is halogen. Halogen gives negative effect on health and environment because of the release of toxic gas following its combustion. An alternative for halogen substitution is using Al(OH)3/Mg(OH)2. Therefore, in this research, the synthesis and characterization of non-halogenic fire retardant composite with epoxy resin and various concentration of additive Al(OH)3/Mg(OH)2 was conducted. The characterization of this research is the fire retardancy, morphology dispersion, and mechanical properties of the synthesized composite, such as tensile strength and hardness. The result of this research is that epoxy resin 50% with 50% of additive Al(OH)3 gives the best flame retardancy behavior and mechanical properties. This composite gives flammability rating V-0 with Tmax 364,3 °C, MLR 12,51 %/menit, total mass loss 57,26%, tensile strength 11,7 MPa, and hardness 79.
Production of Biofuel via Catalytic Hydrocracking of Kapuk (Ceiba pentandra) Seed Oil with NiMo/HZSM-5 Catalyst
Authors: Parahita I Gede Andy Andika , Mirzayanti Yustia Wulandari , Gunardi Ignatius , Roesyadi Achmad , Prajitno Danawati Hari
Published: March 2018

Biofuel is one of alternative energy that is being developed today to solve the problem of limited fossil fuel as an energy source. The goal of this study is to produce biofuel from kapuk (Ceiba pentandra) seed oil (KSO) through catalytic hydrocracking process using NiMo/HZSM-5 catalyst. NiMo/HZSM-5 catalyst was obtained by impregnation of nickel and molybdenum as metallic precursors on HZSM-5 catalyst as support using incipient wetness impregnation method. It was found that the surface area of the catalyst was 222.1350 m2/g, the pore diameter was 3.0148 nm and the pore volume was 0.1674 cm3/g. The diffraction peaks of nickel oxide phase and the metallic phase of nickel were observed at 2θ of 62.5102° and 51.7283°. Molybdenum oxide phases were observed at 2θ of 53.5674° and 60.4682°. The catalytic hydrocracking process was performed using slurry pressure batch reactor at the temperature of 350°C for 2 h. The obtained liquid product was analyzed using GC-MS in order to determine the organic content. It has been found that the highest compounds were the palmitic acid with 23.14 area%. Besides, the hydrocarbon composition consisted of 33.93 area% (i.e. 4.34 area% cycloparaffins, 16.02 area% n-paraffins, 12.26 area% olefins, and 1.30 area% of aromatics) and 58.73 area% of carboxylic acid. Thus, it can be concluded that NiMo/HZSM-5 catalyst can convert KSO into biofuel through catalytic hydrocracking process at the temperature of 350°C for 2 h.
Performance of Dolomite Calcination in a Bench-Scale Rotary Kiln
Authors: Wulandari Winny , Subagjo  , Tri Mursito Anggoro , Juanjaya Fadly Junico , Alwi Muhammad Faqih
Published: March 2018

Dolomite calcination is one of process steps to prepare calcined dolomite for raw materials in magnesium production. Calcination of dolomite involves heating the raw material at sufficient temperature in order to release the carbon dioxide from its carbonate minerals. This process is commonly conducted in a rotary kiln. There have been a number of calcination studies in a laboratory scale, but the study of dolomite calcination in a larger scale is very scarce. This research is aimed to study the performance of dolomite calcination in a bench-scale rotary kiln with 500 gram of feed. The effect of various parameters, including temperatures, feed rate, rotating frequency, and particle size were examined. The temperature of rotary kiln was varied between 700 and 1000 °C, while the particle size of dolomite was varied between 0.149 – 0.297 mm and up to 10 – 15 mm. The temperature distribution inside the rotary kiln was also measured. It is obtained that a conversion of 92% was attained at operation temperature of 1000 °C, which is at a higher temperature compared to the laboratory scale, where a conversion of 100% was obtained at 900 °C. This imply that the effect of heat transfer also plays important role in the calcination of dolomite especially at a larger scale.
Methyl Butanoate Adsorption on MoS2Surface: A Density Functional Theory Investigation
Authors: Prabowo Wahyu Aji Eko , Rustad Supriadi , Sutojo T. , Nugraha  , Subagjo  , Dipojono Hermawan Kresno
Published: March 2018

Methyl butanoate is one of the compound which is obtained from triglyceride molecule. It has hydrocarbon components and hence may produce hydrocarbon through hydrodeoxygenation (HDO) or decarbonylation (DCO) processes. The first step to uncover the underlying mechanism of HDO or DCO is to find the active site of methyl butanoate adsorption over the catalyst. This study attempts to investigate the active site of methyl butanoate adsorption on MoS2surface. Stable bonding configuration for methyl butanoate adsorption on MoS2is investigated by using density functional theory (DFT). This investigation consists of geometry optimisation and adsorption energy calculations. The stable configuration of methyl butanoate adsorption on MoS2surface is found to be on top of Mo atom in Mo-edge surface.
Effect of Catalyst Pellet-Diameter and Basicity on Transesterification of Soybean Oil into Biodiesel using K2O/CaO-ZnO Catalyst over Hybrid Catalytic-Plasma Reactor
Authors: Istadi I. , Buchori Luqman , Putri Brigitta B.T. , Hantara Henrikus I.A.
Published: March 2018

This research is aimed to study the effect of catalyst pellet-diameter and catalyst basicity on the transesterification process of soybean oil into biodiesel over a hybrid catalytic-plasma reactor. Various catalyst diameters (3, 5, and 7 mm) were tested in this reaction system. Catalyst basicity was also examined by comparing fresh and used catalyst as well as with and without K2O promoter. All catalysts testing were performed in a hybrid plasma-catalytic reactor (dielectric barrier discharge – DBD type). From the results, the synergistic effects roles of the catalyst and the plasma in the transesterification process are important, in which the energetic electrons within plasma assist the reaction on the catalyst surface by an exciting bonded electron. The catalyst basicity was influenced by the composition of CaO on the catalyst as well as roles of the alkaline K2O promoter. Catalyst basicity is important in producing biodiesel with high performance. Yield of fatty acid alkyl ester (FAAE) or biodiesel is slightly influenced by the catalyst diameter within the range of diameter studied.
Do ZnO and Al2O3 Nanoparticles Improve the Anti-Bacterial Properties of Cellulose Acetate-Chitosan Membrane?
Authors: Istirokhatun Titik , Yuni Ulva , Andarani Pertiwi , Susanto Heru
Published: March 2018

Biofouling, due to the existence of bacteria in water, becomes one of the barriers in cellulose acetate (CA) membrane applications. Although chitosan has been incorporated into CA membranes, its antimicrobial activity has not been improved significantly yet. In this study, cellulose acetate-chitosan membranes were prepared by modification using ZnO and Al2O3 nanoparticles during phase separation method. The membranes were then characterized in term of water permeability, and surface morphology. The anti-bacteria property was examined by using gram-negative bacteria. Modification of cellulose acetate-chitosan membranes with ZnO and Al2O3 nanoparticles have not shown optimal results where no clear zones around the membrane are visible.
CO2 desorption from activated DEA using membrane contactor with vacuum regeneration technology
Authors: Intan Listiyana Nidia , Rahmawati Yeni , Nurkhamidah Siti , Rofiq Syahnur Hafan , Zaelana Yusuf
Published: March 2018

Carbondioxide (CO2) content in natural gas must be removed because it inhibits liquefication process of natural gas. CO2 gas separation technology using membrane contactor has been developed, however solvent regeneration using membrane contactors are still rare because it requires a larger energy. The regeneration process by using membrane vacuum technology was put forward to reduce the regeneration energy consumption. In this work, arginine, piperazine (PZ), and potassium carbonate (K2CO3) as activators were added into diethanolamine (DEA) solution to form aqueous solutions of activated DEA. The experiment of CO2 desorption from activated DEA was carried out in hollow fibre membrane contactor (HFMC). The solvent with rich CO2 at 30-70°C was flowed in the lumen of the hydrophobic polypropylene HFMC, and the shell side was maintained at a reduced pressure by a vacuum pump at 20 kPa. The effect of solvent temperature and activators were investigated to get CO2 desorption flux and regeneration efficiency. Experimental result shows that increasing of solvent temperature could enhance CO2 desorption flux and regeneration efficiency. Instead of that, the activated DEA also give better result compared with non-activated DEA. Among three activators, K2CO3 give the best result for desorption flux and regeneration efficiency.
Utilization of educational machine tool for training of technical diagnostics based on positioning performance
Authors: Cisar Miroslav , Kuric Ivan , Cubonova Nadezda , Zajacko Ivan , Dodok Tomas , Rudawska Anna
Published: March 2018

The technical diagnostics as essential part of machine tool maintenance provides information about condition of examined machine tool but it requires not only special equipment but also certain level of skill of operators in order to achieve optimal performance. The article is aimed at the set of methods and tools capable of providing realistic simulation of various machine tool conditions in order to allow hone skills necessary for effective diagnostician.
The determination of wormwheel toothing surface
Authors: Nieszporek Tadeusz , Gołębski Rafał , Boral Piotr
Published: March 2018

In heavy industry (metallurgy, mining), large-size worm gears designed to carry large loads are often used. However, their technology is very difficult and their manufacturing costs are very high. In practice, cone-derivative worm gears are most often used, which are machined by the envelope method using a rotary tool. The literature has given much coverage to the determination of the worm helical surface. The surface of wormwheel teeth is much less commonly described. Therefore, this paper presents an analytical and a numerical methods for generating the wormwheel toothing by the tangential and radial methods with a special cutter and with a modular hob.
Modelling of road traffic noise
Authors: Bąkowski Andrzej , Radziszewski Leszek , Dekys Vladimir
Published: March 2018

Effective implementation of the EC Communication relating to urban mobility is dependent on adopting relevant indicators that will allow comprehensive assessment of the measures undertaken under the urban mobility plan. One of the fundamental parameters for this assessment is the equivalent sound level indicator, measured over the 24-hour period, used to evaluate the annoyance of the road traffic noise. Not only is its value important but also its variability. This paper reports the results of the analysis of traffic noise along a major road, performed using various descriptors. The data recorded continuously throughout the year by the traffic rate and noise monitoring terminal were used to construct the measurement database. Analysis of the results was performed for the period between March and June in 2011 and 2016. The road was renovated between 2013 and 2015. The noise variability assessment was conducted using classical and positional indicators. Measurement uncertainties were evaluated.
Determination the maximum load capacity of the welded structure of the transport carriage in operation
Authors: Baniari Vladislav , Handrik Marián , Vaško Milan , Kortiš Ján , Daniel L’uboš
Published: March 2018

The article presents a calculation procedure for determining the maximum permissible load on the welded structure of the transport carriage. During the transport carriages operation inside the production hall there was no breakage of the welding joints. The use of carriages outside the hall and with an uneven surface began to create cracks and fractures in the weld joints. The values of vertical accelerations that were generated by running on uneven surfaces were determined by experimental measurement. To avoid cracks in welded joints, the maximum permissible load value of the transport carriage was subsequently determined by calculation using FEM.
Effect of the pressed ceramic filters on the reoxidation process
Authors: Brůna Marek , Bolibruchová Dana , Pastirčák Richard
Published: March 2018

Article is focused on reoxidation processes during filtration of aluminium alloys. Many of our experiments proven, that when using filtration media in gating system, reoxidation occurs. Main goal of this article is to point out reoxidation problems occurring during filtration of aluminium alloys. Reason to conduct this work was anomalies discovered by experimental casts, which pointed out that after filtration of primary alloys, small oxide films was detected. Oxides was absent, when we poured without filtration media. Simulation software ProCAST was used during our research.
Case study of technological problems arising from the use of new material, DOMEX steel sheet, on the components of the mower discs on the example of the production company SaMASZ Sp. Z o. o.
Authors: Kułak Damian , Jaroszewicz Jerzy , Woronko Marcin
Published: March 2018

The paper describes the improvement of technological process of knife holder production used in disc mowers at SaMASZ Sp. With o.o. The improvement was aimed at eliminating cracks in the press of a 500t crank press press crush that occurred after the Boron 27 starting material was changed to Domex MC 500 high strength steel. The technology of regeneration of claws with identified operational cracks and a stand for fatigue tests was also proposed. Defectoscopy and strength testing methods have been developed to verify that the structure of the regenerated material is free from cracks or micro cracks in the material.
Numerical research of biomechanical system with SMA prosthesis
Authors: Mitura Andrzej , Rusinek Rafal
Published: March 2018

In this paper the modelling of special biomechanical mechanism and application of shape memory materials are presented. The model of the human middle ear is made as multibody system. The basic 3dof ear model of the healthy middle ear is modified to represent the damaged ear. A damaged of the ossicular chainis taken into account by adding gap in visco-elastic joints. In addition, an attempt of the ossicles chain reconstruction through prosthesis made of shape memory alloy is presented. Moreover, a new description of the hysteresis sub-loop which characterise prosthesis material is proposed. Finally, dynamic responses of healthy, damaged and reconstructed models of the middle ear are compared by quality index.
Heat flow and heat transfer coefficient during crystallization under the pressure
Authors: Pastirčák Richard , Ščury Ján , Fecura Tomáš
Published: March 2018

Estimation of the heat flow at the metal-mold interface is necessary for accurate simulation of the solidification processes. For the numerical simulation, a precise prediction of boundary conditions is required to determine the temperature distribution during solidification, porosity nucleation, microstructure development, and residual stresses. Determination of the heat transfer coefficients at the metal-mold interface is a critical aspect for simulation of the solidification process and the microstructure modeling of the castings. For crystallization under the pressure and for thin-walled castings, HTC evaluation is important due to the very limited freezing time.
Numerical simulation of blanking process
Authors: Pecháč Peter , Sága Milan
Published: March 2018

This paper presents numerical simulation of blanking process for cold-rolled steel sheet metal. The problem was modeled using axial symmetry in commercial finite element software ADINA. Data obtained by experimental measurement were used to create multi-linear plastic material model for simulation. History of blanking force vs. tool displacement was obtained.
Computer analysis of thermal phenomena and deformation in lap joint welded by a laser beam
Authors: Piekarska Wiesława , Sapietová Alžbeta , Saternus Zbigniew , Kubiak Marcin
Published: March 2018

Laser welding technology is applied to many types of welded joints. The determination of the influence of technological parameters on the properties of resulting joint is a significant problem for technologists. Numerical estimation of the shape of the weld and its deformation is important in the initial stage of construction design. The paper concerns computer analysis of thermal and mechanical phenomena in laser welded lap joint made of austenitic steel. Three dimensional discrete model of analyzed lap joint is created in Abaqus FEA engineering software. Numerical analysis takes into account temperature dependent thermomechanical properties of austenitic steel. The movable heat source power distribution is modelled using Gaussian distribution. Computational model takes into account the gap between the joined plates. Temperature distribution in analysed joints is presented on the basis of performed numerical simulations. The shape and size of the fusion zone as well as deformation of the joint are estimated.
Analysis of the influence of the pipe’s wall thickness on the corrugation of the surface during inductive bending of pipes
Authors: Sága Milan , Handrik Marián , Kopas Peter , Tropp Maroš
Published: March 2018

The paper presents a calculation model for simulation the technological process of inductive bending of pipes. In the case of an incorrect combination of geometric bending parameters (pipe diameter, bend radius and pipe wall thickness) occurs the corrugation of the inner part in the pipe bend. The proposed calculation model for the ADINA FE software allows for a relatively short time and at low cost to predict the emergence of corrugation.
Stimulation of nerve endings via medical device
Authors: Svoboda Antonin , Soukup Josef
Published: March 2018

This solution describes solution of vibromechanism for stimulation nerve paths and nerve endings injured patients. Medical doctors stimulate nerve paths and nerve endings patients after injury of spine or after another injury where was broken nerve endings. These methods are in primary designed for tetraplegic and paraplegic patients specially for men. For this request was developed device and mechanism for vibrostimulation of nerve paths and nerve endings. In develop of construction has been paying attention to safety of mechanism. Next were taken into account the construction of other devices, especially their shortcomings in the operation on the accumulator. For mains powered vibrators 230 (110) Volt were assessed for safety and noise vibrating mechanism. The sum of all failures was proposed structure described below. The success rate of this vibration method is reported mostly between 60-80%.
Computer aided structural analysis of newly developed railway bogie frame
Authors: Šťastniak Pavol , Moravčík Marián , Baran Peter , Smetanka Lukáš
Published: March 2018

The paper is part of the publication series, which describe the most significant and innovative research and development design solutions and computational procedures as part of European structural funds project. The object of this article is strength conditions assessment of new structure of rail bogie frame, which is characterized mainly by better dynamic properties while driving on the track, good operational properties and higher safety against derailment. For validation of the new structure design, there has been created a substitute simulation model. Results of calculations and prototype tests prove, that new structure of the bogie frame satisfies strength assessments.
Selection of optimal solution heat treatment of the casting cylinder heads
Authors: Tillová Eva , Chalupová Mária , Kuchariková Lenka , Belan Juraj , Závodská Denisa
Published: March 2018

The effect of solution treatment on mechanical properties (UTS, elongation, Brinell hardness) and microstructure (Si-morphology and Si-size) of an aluminium alloy (A356) used for casting cylinder heads was studied. The tests were carried out with specimens machined from the bulkheads of V8 engine blocks cast by the low pressure process. The samples were tested in as-cast and T6 heat treating conditions (solution heat treatment at 530°C with different time - 2, 3, 4, 5, 6, 7 hours, quenching in water at 20°C and precipitation hardened for 4 hour at 160°C). The results show that used heat treatment improves mechanical properties of the cylinder head casts. Tensile strength and hardness of specimens increase with solution treatment time. The hardness is a reflection of solution strengthening and silicon particle distribution in matrix. Solution temperature 530°C and 5 hours solution time is appropriate to obtain better morphology and distribution of Si particles in microstructure. Prolonged solution treatment (more than 5 hours) leads to a coarsening of the Si particles, while the numerical Si density decreases. As the particle density decreases, a fewer number of sites are available for crack nucleation, and hence, the fracture properties are improved. The data obtained from this study will be used to improve process control, and to help the selection of heat treatment of the casting for future products.
Analytical model of stress field in submerged arc welding butt joint with thorough penetration
Authors: Winczek Jerzy , Parkitny Ryszard , Makles Krzysztof , Kukuryk Marcin
Published: March 2018

Analytical model of temporary and residual stresses for butt welding with thorough penetration was described assuming planar section hypothesis and using integral equations of stress equilibrium of the bar and simple Hooke’s law. In solution the effect of phase transformations (structure changes and structural strains) has been taken into account. Phase transformations during heating are limited by temperature values at the beginning and at the end of austenitic transformation, depending on chemical composition of steel while the progress of phase transformations during cooling is determined on the basis of TTT-welding diagram. Temperature values at the beginning and at the end of transformation are conditioned by the speed of heating. Kinetics of diffusional transformation is described basing on Johnson-Mehl-Avrami-Kolmogorov equation, while martensitic transformation, basing on Koistinen-Marburger equation. Stresses in elasto-plastic state are determined by iteration, using elastic solutions method with changeable longitudinal modulus of elasticity, conditioned by stress-strain curve. Computations of stress field have been conducted for one-side butt welded of two steel flats made from S235 steel. It has enabled a clear interpretation of influence of temperature field and phase transformation on stresses caused by welding using Submerged Arc Welding (SAW) method.
Passive safety system for small unmanned aerial vehicles
Authors: Bartkowski Piotr , Zalewski Robert
Published: March 2018

In this paper a new air-bag prototype suitable for protecting valuable objects mounted on the drone is presented. The paper provides a complimentary study involving both numerical simulations and experimental study. The experimental research results are presented for typical air-bag's textile material and were used as a base for the material model calibration process. This model was used for the numerical simulations of the proposed air-bag prototype, which were carried out in the LS-Dyna environment. Based on the outcome of the study, the proposed prototype seems to be a suitable device for preventing the unmanned vehicle equipment from unexpected accidents.
Free vibration analysis of a DST-0285 truck crane considering changes in the system load configuration
Authors: Geisler Tomasz
Published: March 2018

A model of a truck crane, consisting of the fundamental units of the crane, is presented in this paper. The finite element method and a COSMOS/M package were applied to perform the modelling. Research into the influence of a change in the crane radius and load location on changes in the chosen free vibrations was carried out using the built models. Diagrams containing changes in the frequency of vibrations for chosen values of the crane radius and the load are presented and conclusions are drawn.
Kinematic and dynamic analysis and distribution of stress for four-item mechanism
Authors: Vavro Ján , Vavro Ján , Kováčiková Petra , Vršková Juliána
Published: March 2018

This paper presents a kinematic and dynamic analysis and distribution of the stress for four-item planar mechanism by means of the SolidWorks software. Graphic dependence of kinematic and dynamic magnitudes of some points is given in dependence on the angle of rotation of the driving item and in dependence on the time. Distribution of the stress in the items is presented in [Pa]. In relation to the kinematic and dynamic analysis and subsequent simulation of the planar as well as spatial mechanisms, it is great solution to use SolidWorks software program. The considerable advantage of this mentioned program is based on its simplicity from the aspect of modeling and moreover, it is important to point out that utilisation of the mentioned program leads to results which are precise and accurate in the case of the numerical solution of the equations in the whole magnitude referring to motion of mechanism while the given results are obtained in the graphic form.
Design of stirling engine operating at low temperature difference
Authors: Sedlák Josef , Glváč Adam , Czán Andrej
Published: March 2018

There are many sources of free energy available in the form of heat that is often simply wasted. The aim of this paper is to design and build a low temperature differential Stirling engine that would be powered exclusively from heat sources such as waste hot water or focused solar rays. A prototype is limited to a low temperature differential modification because of a choice of ABSplus plastic as a construction material for its key parts. The paper is divided into two parts. The first part covers a brief history of Stirling engine and its applications nowadays. Moreover, it describes basic principles of its operation that are supplemented by thermodynamic relations. Furthermore, an analysis of applied Fused Deposition Modelling has been done since the parts with more complex geometry had been manufactured using this additive technology. The second (experimental) part covers 4 essential steps of a rapid prototyping method - Computer Aided Design of the 3D model of Stirling engine using parametric modeller Autodesk Inventor, production of its components using 3D printer uPrint, assembly and final testing. Special attention was devoted to last two steps of the process since the surfaces of the printed parts were sandpapered and sprayed. Parts, where an ABS plus plastic would have impeded the correct function, had been manufactured from aluminium and brass by cutting operations. Remaining parts had been bought in a hardware store as it would be uneconomical and unreasonable to manufacture them. Last two chapters of the paper describe final testing, mention the problems that appeared during its production and propose new approaches that could be used in the future to improve the project.
Method of controlling innovative articulation for articulated vehicle
Authors: Szumilas Mateusz , Łuczak Sergiusz , Bodnicki Maciej , Stożek Marcin , Załuski Tomasz
Published: March 2018

Operation of an articulated vehicle is dependent on an appropriate damping action taking place in its rotary articulation. In order to analyse an impact of the control of the articulation on the motion of the vehicle a model of the vehicle with a controllable hydraulic damping system has been developed. A 90 degree turn and lane change manoeuvres were simulated using LabVIEW software. Modification of the damping parameters of the articulation, according to the velocity and articulation angle of the vehicle, proved to have a significant impact on the vehicle motion stability. Moreover, the sensor layer necessary for the control algorithm as well as the diagnostic system is described.
The contribution to the modal analysis using an infrared camera
Authors: Dekys Vladimír , Stankovicova Zuzana , Novak Pavol , Stalmach Ondrej
Published: March 2018

The paper deals with modal analysis using an infrared camera. The test objects were excited by the modal exciter with narrowband noise and the response was registered as a frame sequence by the high speed infrared camera FLIR SC7500. The resonant frequencies and the modal shapes were determined from the infrared spectrum recordings. Lock-in technology has also been used. The experimental results were compared with calculated natural frequencies and modal shapes.
Use of the BOINC system for distributed data collection in the “Internet of Things”
Authors: Handrik Marián , Handriková Jana , Jakubovičová Lenka
Published: March 2018

The BOINC software package allows the creation of massive computational systems for distributed computing. The system is designed to use heterogeneous computing devices that are differing in hardware architecture and operating systems. The variability and versatility of the BOINC system allows its use to create a distributed system for measurement and data collection. This is done through the standard HTTP and HTTPS web communication protocol that is used on the Internet in connected devices, so called “Internet of things”.
Determination of the influence of adherent surface on the adhesive bond strength
Authors: Kalina Tomas , Sedlacek Frantisek , Krystek Jan
Published: March 2018

A type of surface and a surface treatment of the adherends has a great influence on strength and durability of bonded joints. This paper deals with an experimental testing of influence of adherent surface on bonded joints strength. Several combinations of materials, surface treatments and two types of adhesives has been designed and manufactured. Those properties were tested on the lap-joints. Samples were made according to the standard ASTM D5868. The materials used were steel S355, aluminium alloy EN AW 7075 T6, carbon fibre laminate and glass fibre laminate. The surface treatments used were: Sandblasted, Mechanically roughened, Anodised, Cataphoretically painted and No-surface treatment. The experimental tests of test specimens were done on the Zwick/Roell Z050 machine. Suitable combinations of material, adhesives and surface treatments were selected based on testing.
Analysis of the material configurations and influence on the dynamic response
Authors: Murčinková Zuzana , Halapi Michal
Published: March 2018

The paper presents the analysis of the material configuration of composites based on the measurement of their dynamic response. The article presents the measurement scheme, the design of the measuring stand together with the analysis of the results. Moreover, it analyses the FFT spectrums of layered long fibre composite, short fibre composites of different fibres materials and homogeneous materials as steel and aluminium alloy.
Experimental testing of PLA biodegradable thermoplastic in the frame of 3D printing FDM technology
Authors: Beniak Juraj , Križan Peter , Matúš Miloš , Šajgalík Michal
Published: March 2018

In the present time there are many different plastic materials and composite materials suitable for 3D printing by deposition of semi-melted material. The proper selection of correct material with suitable material properties is dependent on the situation how the produced 3D model should be used. If we need to take into account just the visual look of used material or also the mechanical properties as strength is important for loaded models for final use. The aim of this paper is to publish outputs of experimental testing for 3D models from selected materials with regards to mechanical properties of produced testing parts. Produced 3D models are from PLA biodegradable thermoplastic. Models are prepared on Fused Deposition Modelling (FDM) 3D printer. Testing is based on prepared full factors experiment with four factors on its two levels. Measured values are Tensile strength of PLA testing 3D models. In the same time there are gathered information regarding the 3D printing process and compared to measured tensile strength values for each sent of testing parts. All the measured data are statistically evaluated also by Analysis of Variance (ANOVA method).
Analysis of torque cam mechanism
Authors: Hren Iryna , Hejma Petr , Michna Štefan , Svoboda Martin , Soukup Josef
Published: March 2018

The article deals with the process of torque camshaft at a constant speed. The method of release was determined by the normal force acting between the cam and the tappet. Subsequently, was expressed torque. A prerequisite for the calculations are a constant friction coefficient between the components of the mechanism and constant speed of the camshaft. Cam used for the purposes of this study generated polynomial lifting dependence. Part of this work is the calculation methodology lifting addiction. Course of torque is the conclusion presented on the values of the corresponding measuring station, which is the result of previous work on the subject.
Numerical modelling of the rigid polyurethane foam microstructure
Authors: Pozorski Zbigniew
Published: March 2018

The paper presents a numerical model of 2-D microstructure of rigid polyurethane foam. The selection of geometric and material parameters is presented. For a particular structure, its behavior has been studied for typical cases of external loads (or forced displacements). The characteristic phenomena have been identified and described. A parametric analysis was performed due to the dimension of the cross-section of the struts which form the cell edges. An analysis of the impact of support and loading conditions on the behavior of the cell structure was performed.
Study of selected thermoplastics using dynamic mechanical analysis
Authors: Kohutiar Marcel , Pajtášová Mariana , Janík Róbert , Papučová Iveta , Pagáčová Jana , Pecušová Beáta , Labaj Ivan
Published: March 2018

The aim of given paper is to study selected polymers using dynamic mechanical analysis method (DMA). DMA is one of the most useful techniques for the study of the viscoelastic behaviour of thermoplastic polymers. In relation to DMA, an oscillatory stress and strain is applied to the material at specific frequencies and temperatures and based on this mentioned fact hereinbefore, the resulting changes after the loading in the material are measured. This technique allows detecting the melting temperature and the glass transition temperature of the thermoplastic materials. Furthermore, some spectroscopy techniques, such as energy dispersive X-ray spectroscopy (EDX) and infrared spectroscopy (IR), were also used for the investigation of the thermoplastics. The thermoplastics used for examination, namely polyethylene, polystyrene, polypropylene and polyethylene terephthalate, were gained from the waste of the packaging.
Study of new rubber to steel adhesive systems based on Co(II) and Cu(II) sulphides coats
Authors: Labaj Ivan , Ondrušová Darina , Dubec Andrej , Pajtášová Mariana , Kohutiar Marcel , Pecušová Beata
Published: March 2018

The presented paper deals with the preparation of new rubber to steel adhesive systems using the steel surface treatment with deposition of adhesive coats based on Co(II) and Cu(II) sulphides. Efficiency of new prepared adhesive systems containing Co(II) and Cu(II) sulphides has been compared with the efficiency of double layer adhesive system commonly used in industry. The chemical composition of prepared adhesive systems was determined using the EDX analysis. Scanning Electron Microscopy (SEM) was used for study of topography and microstructure of prepared rubber to steel adhesive systems (Co(II), Cu(II) sulphide, double layer adhesive system). For determination of adhesion strength between rubber blends and metal pieces with various adhesive systems deposited on these pieces, the test according to ASTM D429 standard relating to Rubber to metal adhesion, method A was used. For all test samples, the same type of rubber blend and the same curing conditions have been used.
Temperature dependent measurement of internal damping of austenitic stainless steels
Authors: Oravcová Monika , Palček Peter , Chalupová Mária , Uhríčik Milan
Published: March 2018

This article is aimed on the analysis of the internal damping changes of austenitic stainless steels AISI 304, AISI 316L and AISI 316Ti depending from temperature. In experimental measurements only resonance method was used which is based on continuous excitation of oscillations of the specimens and the whole apparatus vibrates at the frequency near to the resonance. Microplastic processes and dissipation of energy within the metals are evaluated and investigated by internal damping measurements. Damping capacity of materials is closely tied to the presence of defects including second phase particles and voids. By measuring the energy dissipation in the material, we can determine the elastic characteristics, Youngs modulus, the level of stress relaxation and many other.
Triaxial analysis of residual stress in surface layers after high feed machining using X-ray diffractometer
Authors: Sajgalik Michal , Czanova Tatiana , Zauskova Lucia , Drbul Mario , Sadilek Marek , Valicek Jan
Published: March 2018

Continuously increasing of productivity is main cause of finding of new ways and methods of machining. High feed machining (HFM) is one of methods of high-productivity machining developed to achieve higher metal removal rates and decrease machining time. Each machining or treatment operation introduces residual stress into the material and its surface layers. Roughing methods of machining generate tensile residual stress obviously. Tensile character of residual stress is not suitable for functional properties of produced parts. In some cases, finishing methods of machining can improve residual stress to suitable character. New detection method of residual stress by applying of x-ray diffraction allows to measure residual stress as triaxial tensor and distribution of residual stress. When we know analyse the residual stress thoroughly, we can design right finishing method and so improve the character of residual stress. This article is focused on analysing given measuring method of residual stress in triaxial direction and next possibilities of their eventual improvement.
The influence of the structure on the fatigue properties of aluminium alloys for the casting
Authors: Uhríčik Milan , Palček Peter , Chalupová Mária , Frkáň Martin
Published: March 2018

The article will be focused on monitoring the influence of the structure on the fatigue properties of Al-Mg cast alloy. As an experimental material were used aluminium alloys EN AC 51200 and EN AC 51500, supplied in a cast state without a heat treatment, which were produced by the continuous casting method. These alloys were selected on the basis of the chemical composition, where the content of most alloying elements is comparable. Fatigue properties of aluminium alloys were tested by three-point bending cyclic loading. The fracture surface of the testing sample was examined using scanning electron microscopy (SEM), where samples were observed on various stages of the fatigue process, their characteristics and differences of fracture surfaces.