bluuebunny/crossref_metadata_2025 huggingface dataset:
Fourier Transform Infrared (FTIR) Spectroscopy and X-Ray Diffraction (XRD) Analysis of Synthetic Waste during Combustion Process
Authors: Sukarni Sukarni , Saputra Lukman Arifianto Andi
Published: July 2020

The availability of synthetic waste (SW) continuously increases, but on the contrary fossil fuels resources always decrease. The potential of SW for alternative fuel is critical to investigate for overcoming the problem generated from its overabundance and to provide its value-added. In this study, the changes of the macromolecular and the mineralogical during the SW combustion processes were investigated by Fourier Transform Infrared (FTIR) spectroscopy and x-ray diffraction (XRD), respectively. The combustion has been performed by using thermogravimetric analyzer (TGA) at a heating rate of 10 °C/min, from 25 to 1000 °C, with 100 ml/min constant flowrate of air atmosphere. According to the TGA results, the decomposition stage of the sample can be identified as a function of temperature and time. From ambient temperatures to 293 °C the sample experienced the first decomposition process that was correlated with the moisture losses and light volatile release. Macromolecular changes occurred at the temperature 293 °C where functional group of C–H in methylene was decomposed due to the removal of volatile matter. From the temperature of 293 to 485 °C the sample underwent the second stage of decomposition. The XRD result showed that mineral changes occurred at the temperature of 485 °C where the KCl compound was formed. In line with the escalating temperature, SiO2 was decomposed at a temperature of 590 °C. The final stage occurred at the temperature 625 to 1000 °C indicated by constant of TG line. At 625 °C, XRD result indicated the significant increasing of the CaCO3 compound.
The Effect of Additional Zinc Oxide to Antibacterial Property of Chitosan/Collagen-Based Scaffold
Authors: Alfata Rowi , Ramahdita Ghiska , Yuwono Akhmad Herman
Published: July 2020

The bone scaffold is susceptible to infection in its application due to the bacteria that often appear on the surface. To prevent this phenomenon, the scaffolds need to be modified in order to provide antibacterial properties. In this study, the bone scaffold was fabricated from chitosan-collagen with the addition of zinc oxide as an antibacterial agent. There were four variables of the amount of zinc oxide added to the scaffold: 0%, 1%, 3%, and 5%. The method used was Thermally Induced Phase Separation (TIPS). From this study, a porous scaffold with a rough surface was obtained. SEM image of the scaffold showed that more zinc oxide caused smaller pore and lower porosity. Characterization with FTIR proved that the scaffold obtained from this process has the same functional group as chitosan and collagen. The DSC-TGA curve confirmed that the heating process performed on dehydrothermal treatment (DHT) did not cause degradation of the scaffold because chitosan and collagen have higher degradation temperatures than DHT temperatures. In addition, this study also proved that the addition of zinc oxide had successfully provided the scaffold with antibacterial properties in which the protection against bacteria was related to the amount of zinc oxide in direct proportion.
Response Surface Methodology Study on Macroporous Hydroxyapatite Prepared by Protein Foaming-Consolidation Method
Authors: Fadli Ahmad , Huda Feblil , Komalasari  , Habib Ilham , Arosyidin Arosyidin
Published: July 2020

Macroporous hydroxyapatite have been used in biomedical application especially for bone graft. The objective of this research was to study the effect of yolk addition, rate of sintering temperature rise, and rate of stirring on the physical, chemical and mechanical properties of porous hydroxyapatite prepared using protein foaming-starch consolidation method. The slurry was made by mixing the hydroxyapatite and starch powder with Darvan 821A and yolk in a beaker glass. The slurry was stirred mechanically at rate of 150 rpm for 3 hours and it poured in cylindrical mold. Subsequently the slurry was heated in air oven at 180°C for 1 hour. The dried green bodies were burn out at 600°C ended by sintering at 1250°C. The porous hydroxyapatite with average pore size in the range of 13.7-17.9 μm, porosity of 59.3-63.6 % and compressive strength of 5.17-8.2 MPa was obtained. The calculation result of response surface methodology shows that p-value < 0.05 and lack of fit > 0.05. The most effecting factor significantly was hydroxyapatite addition that followed by mixing rate and temperature rising rate of sintering. Optimum condition hydroxyapatite addition of 22 gr, mixing rate of 150 rpm and temperature rising rate of sintering of 2.8°C/minutes with the optimum value of response for pore size by 17.665 μm, porosity by 63.475% and compressive strength 5.17 MPa.
Degradation Characteristics of Mg-1,6Gd Alloy at Low Thickness Reduction of Warm Rolling
Authors: Hidayat Ahmad Nabil Faiz , Zakiyuddin Ahmad , Harjanto Sri , Susanti Oknovia
Published: July 2020

Magnesium has been developed as a biodegradable bone implant material due to its similarity in elasticity modulus of bone. However, magnesium has a higher corrosion rate and a lower strength. Gadolinium is alloyed to magnesium in order to improve the corrosion resistance and then rolled to improve the strength due to grain refinement in rolling. Cold roll produced the finest grain, but magnesium has a poor formability. Due to this fact, warm rolling with temperature 247 – 375 oC is applied. Optical Microscope, Scanning Electron Microscope (SEM), and Energy Dispersive Spectrometry (EDS) are used for characterization. Electrochemical Impedance Spectroscopy (EIS) and Polarization test were carried out to observe the corrosion mechanism of Mg-Gd in SBF Kokubo to replicate a human body condition. The result of polarization test shows that the cross-rolled sample experienced an increase in E corr, with 0,15 and –0,048 V due to a better distribution of Gadolinium. EIS states that the single pass rolled sample has a stronger passive layer with 116 and 126 kΩ value of Rf due to a smaller grain size which resulted a fewer compression stress. The hydrogen evolution was also observed with immersion test. Keywords: uni-directional rolling, cross-directional rolling, corrosion, simulated body fluid, hydrogen evolution.
Delamination Damages of Drilling Epoxy/Carbon/Basalt Fiber Reinforced Hybrid Composites Using Conventional Drill Machine
Authors: Subagia I Dewa Gede Ary , Sutantra I Nyoman , Yuwono Akhmad Herman
Published: July 2020

This experiment is to investigate delamination damage of carbon/basalt/epoxy hybrid composites on the drilling manufacturing process. The damage is caused by drilling on wet and dry conditions with a twist drill size of 8 [mm], and 10 [mm] have been conducted. This experiment was carried out based on the ASTMD 5470-12 standard. Three hybrid composites have been manufactured for samples such as H1, H2, and H3. Additionally, the carbon fibers reinforced epoxy composites (CFRP) and basalt fibers reinforced epoxy composites (BFRP) as experiment control had built. The aim is to assess the defect zone of carbon/basalt hybrid composite against the drilling. The examination results showed that the feed rate speed of various laminate configurations e.g., H1, H2, and H3, on drilling dried between twist drill of 10 [mm] and 8 [mm] diameters are 50.5 %, 25 %, and 33.2 %, respectively. Also, adding lubricant during the drilling work has reduced peel-out and push-out effectively. The delamination defect has been the high resulted in drilling using drill 10 [mm] in wet or dry conditions. In contrast, delamination defect has occurred minimum on drilling hole using twist drill 8mm in work wet and dry condition. It has still occurred. From this research, the combination sequence of basalt and carbon fiber has the possibility to experience the delaminate damage in dry drilling processes.
The Development of Natural Rubber Composite Based Canal Blocking to Sustain Peatland Environment
Authors: kinasih norma , Stevanus Charlos T. , Nugraha Iman S. , Aprizal Alamsyah , Cifriadi Adi , Wijaya Thomas , Maspanger Dadi R. , Ramadhan Arief
Published: July 2020

Peatland fire became a serious problem in Indonesia until nowadays. The most problem of peat fire was caused by converting peatland become plantation area, wherein need canal blocking to adjust water ground as crop planting requirement in peatland. The structure design of this canal blocking should be strong enough to block excessive water level degradation so that can sustain the peatland environment. The current design of canal blocking was used wood as building structure, which has nor water-resistant, therefore, it can be rotten and easy to collapse. Indonesian Rubber Research Institute (IRRI) has already developed novel technology of canal blocking, namely natural rubber composite based water level canal blocking to overcome this problem. This novel technology was used natural rubber composite as material structure, therefore it has higher water-resistant, longer service life, and higher acid resistance than traditional canal blocking. In addition, novel canal blocking has equipped with water level system, which could control the groundwater level were suitable enough for crop planting requirement in peatland. Indeed, novel canal blocking could sustain peatland environment through peatland fire risk reduction, carbon dioxide (CO2) emission reduction and increase peatland plantation production. This technology has already installed in South Sumatera. Present work would be detailed review structure strength novel canal blocking, environment and economic impact on its application. The application result had determined successful to reduce CO2 emissions up to 3,723.38 ton CO2 /ha during 7 months installation. Furthermore, the production of the intercropping system (palm oil and corn) in peatland within novel canal blocking was increasing the profit wherein the B/C of novel canal blocking application was 1.77, while traditional design canal blocking application was 1.55.
The Role of Al2O3 Particles on Mechanical Properties and Microstructure of Aluminum A356 Composites Produced by Stir Casting Method
Authors: Haritsa Hanuna , Akira Muhammad Wira , Zulfia Syahrial Anne
Published: July 2020

This study was conducted to investigate the effect of Al2O3 on characteristics of A356 reinforced composites. The addition of Al2O3 as reinforced varied from 2 vf-% to 15 vf-% through Stir Casting methods to obtain the optimum addition Al2O3 as reinforced in mechanical properties of composite A356 as matrix and Al2O3 as reinforcement. Magnesium with of 10 wt-% was added to improve wettability between Al2O3 particles and Al A356. Addition of Magnesium is expected to form the spinel phase MgAl2O4 in interface area between Al2O3 and Al A356.The optimum tensile strength was found at 2 vf- Al2O3 with value 131.55 Mpa. However, the value is still lower than the tensile strength of Al A356 As cast. It is caused due to the porosity and the agglomeration of Al2O3 were found in the microstructure of the composite Al A356/Al2O3. The Hardness increased from material monolithic Al A356 as cast, reached 37.43 HRB.
The Strength of Polylactic Acid Composites Reinforced with Sugarcane Bagasse and Rice Husk
Authors: Anggono Juliana , Budiarto Bily , Sugondo Suwandi , Purwaningsih Hariyati , Antoni Antoni
Published: July 2020

There are more than 1000 species of cellulose plants available in fiber form. A number of them are by-products from the major food crops contain lignocellulosic sources and being investigated as composite reinforcement materials. Sugarcane bagasse and rice husk are potential reinforcement materials and they were used to reinforce polylactic acid (PLA) matrix to make green composites. In this research work, sugarcane bagasse was given two different kinds of treatment; some were alkali treated using 8 wt.% NaOH at room temperature for an hour and some other were steam treated at 0.75 MPa for 30 minutes. The fiber content of the composites changed with weight percentage ratios of sugarcane bagasse/rice husk/PLA was 25/0/75, 25/5/70 and 25/10/65. Flexural strength was tested in accordance with ASTM D790-17 and structural evaluation was evaluated using scanning electron microscope (SEM) on the fracture section of the flexural test samples. Composites produced using steam treated sugarcane bagasse and rice husk have lower area density (1277-1385 g/m2) compared to the ones formed using NaOH treated bagasse and rice husk (1162-1500 g/m2). Both values of area density are below the density of neat PP and wood flour reinforced PP/PE composites used as reference materials. The flexural test shows the NaOH treatment on the bagasse fibers improve the flexural strength of the composites but the rice husk content introduced to the structure reduces the strength of the composites. SEM evaluation shows fiber fracture and few pull-out.
Optimizing Performance of Li4Ti5O12 (LTO) by Addition of Sn Microparticle in High Loading as Anode for Lithium-Ion Batteries
Authors: Priyono Bambang , Ulum Reza Miftahul , Zulfia Anne , Trixie Stefanie , Jodi Heri , Ramadhan Laksamana Zakiy , Subhan Achmad
Published: July 2020

Li4Ti5O12/Sn was successfully synthesized by a solid-state method using the High Energy Ball Mill Machine as anode for Lithium-Ion batteries. The addition of various (10%, 20%, 30%) Sn-micro particle is aimed to enhance LTO's conductivity and capacity. Characterization of the sample's structure was performed using X-ray diffraction (XRD), which expose the presence of TiO2 rutile and Sn in each sample. The surface area of samples observed using Brunner-Emmet-Teller (BET), which indicates the different surface area of each Sn addition. Scanning electron microscopy (SEM) suggested agglomeration and poor distribution appear in every sample. Cyclic voltammetry (CV) was performed to measure the battery's performance. Two peaks occur as a sign of reversible reaction. The impedance of Li4Ti5O12/Sn measured using electrochemical impedance spectroscopy (EIS), the test performed before and after Cyclic voltammetry (CV), each test showed the different result for each sample. Other than EIS and CV, Charge-Discharge (CD) also performed, examinations in different C-rate were performed, and higher Sn concentration leads to lower stability in high C. The result reveals that the addition of 20% Sn optimizes Li4Ti5O12 in enhancing capacity and conductivity.
Tribological Study of Addition Oleic Acid in Palm and Coconut Oils as Bio-Lubricants
Authors: Gasni Dedison , Fikri Ikhsanul , Latif Muhammad
Published: July 2020

The purpose of this study was to investigate the influence of oleic acid as an additive in palm and coconut oils on tribological properties. Palm and coconut oils are vegetable oils that are consisted of free fatty acid, which one of the materials used as a source of environmental lubricant. Fatty acids in vegetable oil consist of saturated fatty acids and unsaturated fatty acids. Palm and coconut oils are rich in palmitic acid, which is categorized as saturated fatty acids. Whereas oleic acid is unsaturated fatty acids, and it has good lubricity as a lubricant. The effect of variation of oleic acid (10wt%, 20wt%, and 30wt%) in palm and coconut oils was investigated on tribological properties. The tribological properties were investigated by using a pin on disc apparatus and a ball bearing test rig. The results show that the effect of 10%wt oleic acids in coconut oil significantly increased its tribological properties with Δ scar width around 96 μm and 154 μm for the inner race and outer race, respectively.
Local Silica Sand as a Substitute for Standard Ottawa Sand in Testing of Cement Mortar
Authors: Pratiwi Wieke , Karim Gaos Abdul , Rachmawati Titi
Published: July 2020

Compressive strength of cement mortar is an important parameter in the quality control of Portland cement. The limitation of Ottawa sand imports has prompted a study on the potential and utilization of local silica sand available in several regions in Indonesia. The purpose of this study was to investigate the potential and possibility of utilizing local silica sand from several regions in Indonesia including Bangka, Belitung, Sidrap (South Sulawesi Province) as a substitute for standard Ottawa sand in cement mortar testing. Evaluation of local silica sands consisted of SEM analysis, characterization of silica sands and testing of cement mortar compressive strength. Silica sands from Bangka, Belitung and Tuban had silica content of more than 90%, while that from Sidrap was more or less 90%. Based on the SEM analysis, characteristic of silica sands, and compressive strength of cement mortar, local silica sand from Sidrap (South Sulawesi Province) has a good potential to be used as a substitute for standard Ottawa sand in testing of cement mortar.
Surface Mechanical Properties of Tool Steel on the Addition of Carbon Nanotubes with the Process of Flame Spray Tungsten Carbide Coatings
Authors: Mudiantoro Sunoto , Gerry M. , Winarto Winarto , Anis Muhammad , Kemal M. , Fadzli M.
Published: July 2020

Tungsten Carbide (WC) hard coating is widely used to coat the surface of the steel tools which provide tribological properties. In this paper, 0.25 wt% & 0.35 wt% of Carbon Nanotubes (CNT) were mixed with tungsten carbide (WC) powders as the feedstock powders. Method of solution dispersion in ethanol media using an ultrasonic device was used for coating the surface of WC powders with CNT powder. The mixed powders were then used as the feedstock powder to coat onto the surface of tool steel using the flame spraying process. The coated surface microstructures were observed under a scanning electron microscope (SEM), x-ray diffraction (XRD), and the energy dispersive spectroscopy (EDS) was used for the phase characterization and identification. The wear rate of coated steels was determined using the Ogoshi machine, and the Vickers hardness method used to measure their microhardness. The effects of CNT on the microstructure of the coated material and the surface mechanical properties were investigated. The results showed that the mixture powder preparation using an ultrasonic method in SDS solution and the ball-milling process was suitable to disperse the CNT on the surface of WC feed powders due to produce an adequate relationship between CNT' and WC powders increasing the surface mechanical properties of coatings. The wear resistance of the coated material produce using the mixture of WC powder with 0.35 wt% CNT increased around 50% higher than the WC coated steel without CNT addition. Also, the hardness of coating reinforced CNT increased significantly compared with the hardness of WC coated and the steel substrates. Microhardness value from the base metal to the WC-CNT coated steel increased from 550 HV to 1717 HV and also the wear rate from the base metal to the WC-CNT coated steel decreased from 0.86 mm3/min to 0.017 mm3/min. These results indicate that CNT is an excellent alternative to improve the surface mechanical properties of WC coatings.
The Comparison of Nitrogen Atom Solubility in the Formation of Surface Layer on Stainless Steel and Alloy Steel
Authors: Widi I Komang Astana , Sujana Wayan , Rahardjo Teguh
Published: July 2020

The chrome alloy has better affinity with nitrogen atom in nitriding process than any other alloy elements in steel. The higher content of chrome element binds larger number of nitrogen atoms. However, the higher concentration of nitrogen atom on the surface of the steel does not often make thicker case depth. This study clarified the phenomenon. The nitriding process was performed in two stages, namely the boost stage in the fluidized bed with the composition of 80 % NH3 and 20 % of N2 in 4 hours at 550 °C. Subsequently, the diffusion process was carried out in fluidized bed with the gas composition of 100 % N2 HP (high purity) in 2 hours. The chemical composition was measured by spectrometry and EDAX. The case depth was identified by micro-Vickers, and metallography was observed by SEM. The concentration of nitrogen atom on the surface of AISI 316 L is twice higher than that on the AISI 4140. The result shows that 0.1 to 1 wt % of nitrogen atom creates diffusion layer, 1 to 5 wt % of nitrogen atom produces nitride layer of γꞌ and ε, and nitrogen atom above 5 wt % forms white layer. The layer strongly depends on the percentage of nitrogen atom concentration. The nitrogen atom concentration is determined by the concentration of chromium element within the steel (AISI 316 L). Meanwhile, the depth of nitrogen atom diffusion is highly determined by the alloy element of Fe (AISI 4140).
Study on the Effect of Bleaching Treatment on the Mechanical Properties of Kenaf Fibers
Authors: Husnil Yuli Amalia , Yuanita Evana , Ramadhani Nurfitri , Chalid Mochamad
Published: July 2020

Automotive industries are trying to reduce the weight of cars by replacing parts that are made of steel and aluminum with lighter material but equally strong. It is an emerging trend in these industries to utilize polypropylene reinforced with natural fiber as the alternative lightweight material. PP-natural fiber composite is projected to have market growth with compound annual growth rate (CAGR) of 9.5% within 2018-2025. Blending PP with natural fiber is a challenging process considering these two materials are not compatible enough to produce composite with desired mechanical properties. Prior treatment to the fiber is required to improve its compatibility with PP with cautionary that it does not degrading the mechanical strength of the fiber. The aim of this work was to study the effect of chemical treatment on Kenaf fiber to the tensile strength of the fiber. Kenaf fiber was bleached with NaClO solution at various concentration (1-10% v/w), temperature (25-55°C), and duration (1-6 hours). The effect of bleaching treatment to the chemical structure and the tensile strength of the fiber was analyzed using FTIR and UTM respectively. This study showed that the fiber with highest tensile strength was the one that treated with NaClO solution with concentration 1% v/w, at 25°C for 1 hour. This treatment removed impurities for the surface and reduced some amorphous part of the fiber. However further increasing NaClO concentration, mixing temperature and duration will damage the cellulose chain in Kenaf fiber which will decrease the mechanical strength of the fiber.
Characterization of LTO/Silicon Oxycarbide with Activated Carbon Addition for Anode of Lithium-Ion Batteries
Authors: Priyono Bambang , Fitratama Mochamad Febby , Roulli Shania , Subhan Achmad , Zulfia Anne
Published: July 2020

Lithium Titanate (LTO) is one of the anode materials that has good performance because of its unique properties, which is zero-strain. In this study, LTO was synthesized using the sol-gel method and mechanochemical hydrothermal with LiOH as the source of lithium-ion. Silicone oxycarbide (SiOC) is a ceramic material synthesized through a simple pyrolysis process of silicone oil precursors. Carbon used in this study is a carbon activated process so that activated carbon is obtained with a large pore size. The addition of activated carbon to the LTO is done during the sol-gel process, while the addition of SiOC to LTO-C is performed during the slurry making process. SEM-EDS shows the extent of the elements in the sample where Ti, F, Si, O, and C are present. Also, SEM-EDS characterization shows an increase in the amount of carbon in each sample. XRD shows the presence of the LTO spinel phase and impurity phases such as TiO2 rutile and anatase, and Li2TiO3. In EIS performance testing, low resistivity expresses high conductivity. In this research, high conductivity is owned by LTO-1% C/SiOC. In addition, CV and CD performance tests were performed where the highest specific capacity was obtained in the LTO-5%/SiOC samples.
Study of Zeolite Usage in Thermal Degradation Process of Polypropylene Pyrolysis
Authors: Rahmat Naufal Ghifari , Jaka Fajar Fatriansyah , Dhaneswara Donanta , Kaban Agus Paul Setiawan
Published: July 2020

Plastics materials have been an integral part in people’s daily life due to their high elasticity, formability and lightweight characteristics which are suitable for many products. However, exponentially growth of plastics waste leads to heavy environmental problems due to the plastics nature which is not easily degradable. One of solution to alleviate environmental problems due to plastics waste is to use pyrolysis method to burn plastics waste and convert them into lighter hydrocarbon which can be used as a source of energy. In this final project, the addition of zeolite catalyst in pyrolysis process of Polypropylene plastic waste has been studied in the terms of energy activation. Isoconversional Friedman and Flynn-Wall-Ozawa methods were used. The results may suggest that the role of zeolite as catalyst is pronounced only in the early stage of pyrolysis process. Keywords: plastics waste, Polypropylene, Zeolite, Friedman, Flynn-Wall-Ozawa
Alteration in the Phase Morphology of Ti-6Al-4V Alloy Produced Using Directed Energy Deposition
Authors: Nursyifaulkhair Desrilia , Mawardi Faris Arief , Park Nokeun , Baek Eung Ryul , Kim Sungwook
Published: July 2020

The alteration in phase morphology of Ti-6Al-4V alloy fabricated using directed energy deposition (DED) was investigated in this study. Owing to the fast cooling rate during DED, the specimen exhibited the diffusionless transformation products of martensite (α′) and massive (αm) phases. In the top layer, the α′ exhibited a needle-like morphology with the width of approximately 0.94 μm. Meanwhile, the αm presented a lamellar structure with α thickness of nearly 0.98 μm. In contrast, the morphology of α′ and αm started to decompose into α+β phase in the bottom layer. Furthermore, the hardness values increased with higher deposition layers. These phenomena could be explained by the effect of repetitive heating, as the nature of DED method during the depositing of new layers. Moreover, it was observed the α thickness of αm in the bottom layer was finer than that in the top layer due to the higher cooling rate.
Die Soldering Behavior of H13 and Cr-Mo-V Tool Steel on Die Casting Process on Nitriding-Shot Pinning Die Surface Treatment
Authors: Mochtar Myrna Ariati , Aldila Rizki
Published: July 2020

Die soldering is a sticking phenomenon between molten aluminum with the surface of steel die in the die casting process, which results in damage to the cast products and l the steel die. In this research, two die materials, H13 and Cr-Mo-V steels were used. Those dies were then treated by two process variables, shot pinning and nitriding-shot pinning. To simulate the die casting process, the samples were dipped into molten Aluminum-Si alloy, ADC12 at 680oC for 30, 300, and 1800 seconds. Characterizations were focused on the surface of the steel, which includes microstructure observation by a microscope, microhardness profile, compound identification, and weight loss measurements. It was found that H13 steel and Cr-Mo-V steel treated by nitriding–shot pinning have higher hardness up to 100% and thinner intermetallic layer. On H13 steel, the compact layer thickness decreased from 19 μm to 17 μm and from 96 μm to 80 μm for the broken layer. Similar trends occurred for Cr-Mo-V steel, where the thickness of the compact layer and broken layer decreased from 38 μm to 19 μm and 119 μm to 45 μm respectively. These results indicate that H13 and Cr-Mo-V steels that were treated by nitriding–shot pinning have a better resistance to die soldering.
Effect of Cooling Rates during a Double Stage Solution Treatment on the Massive Phase Formation in Ti-6Al-4V Alloy
Authors: Suprobo Ghozali , Mawardi Faris Arief , Park Nokeun , Baek Eung Ryul
Published: July 2020

The effect of cooling rates during a double stage solution treatment (DSST) on the volume fraction of the massive phase (αm) in Ti-6Al-4V alloy was successfully confirmed in the present study. The morphology of Ti-6Al-4V alloy depends on the cooling rates during the cooling from the β region. The αm, which has a transformation characteristic between martensite (α′) and α diffusion, is reported to be a potential method for obtaining a fine lamellar α/β by thermal decomposition. The different fraction of αm was found after DSST with the first stage was conducted above the β-transus temperature at 1050 °C, followed by second annealing at different temperatures in the α+β region. It was found that the formation of αm exists in a specific temperature region. A longer period in this region, which was calculated based on different cooling rates during DSST, will increase the fraction of αm in the specimen. All specimens after DSST contain αm with the α width of approximately 1μm and white-dot particles, which is predicted to be V-enriched precipitates. The DSST can be a potential method for producing a high fraction of αm, which can be thermally decomposed into a fine lamellar α/β, introducing a Ti-6Al-4V alloy with superior mechanical properties.
Evaluation of Austenite Grains Growth in High Nb and Low Nb HSLA Steel
Authors: Siradj Eddy Sumarno
Published: July 2020

This study was presented due to the increasing demand of High Strength Low Alloy (HSLA) steel, such as demand for thinner-walled and large diameter pipes in oil and gas industries. In order to meet the imposed economic restrictions, the high standard of all kinds of steel properties is required and can be achieved by controlling the steel microstructure. The austenite grain size influences the microstructure and properties of steel significantly, in which fine austenite grain size leads to higher strength, better ductility, and higher toughness. Studying the behavior of steel grain growth during the reheating process is still being a fascinating subject. P.R. Rios and D Zollner [1] mentioned that grain growth is the most important unresolved issue that has been a topic of research for many years. In this research, the behavior of austenite grain growth at a high niobium-low carbon (High Nb-low C) and low Nb-high C HSLA steel was evaluated, and the result was compared with other investigation. The results found that the austenite grain growth at high Nb-high C steel was slower than the growth at a low Nb-low C steel. The activation energy of austenite grain growth and both constant A and exponent n ware determined close agreement was obtained between the prediction of the model and the experimental grain size value.
Influence of Manganese on the Recrystallization Characteristics and Texture Development of Cu-29Zn Alloys
Authors: Basori Imam , Sofyan Bondan Tiara
Published: July 2020

Studies regarding the recrystallization texture of brass alloys are quite complex. Previous experiments showed that the addition of the alloying elements on brass alloys affect the deformation mechanism and texture development. Alloying elements promoted the inhomogeneous deformation and resulted in a heterogeneous microstructure. During annealing, the new grains form around the shear band area and develop the random texture. This research studied the effect of Mn addition on the recrystallization characteristics and texture development of Cu-29Zn alloys. The Cu-Zn-xMn alloys were produced by gravity casting with a dimension of 110x110x6 mm3. The feeding material includes pure Cu, Zn, and Mn. The as-homogenized samples were then cold-rolled with the level of deformation of 70 % and followed by an annealing process at temperatures of 400, 500, and 600°C. Samples characterization includes chemical composition analysis, microstructure observation, hardness testing, and texture measurement. The results showed that the addition of Mn tended to reduce the rate of recrystallization and grain growth. At 70% deformation, Mn addition promoted the formation of brass and Goss texture. The presence of Mn also influenced the formation of recrystallization and annealing texture.
Investigation of Dynamic Recrystallization Phenomenon in Drawn Ti-6Al-4V Alloy
Authors: Nugroho Janu Ageng , Suprobo Ghozali , Park Nokeun , Baek Eung Ryul
Published: July 2020

The microstructure evolution during the drawing process of Ti-6Al-4V alloy with a lamellar morphology as an initial microstructure was investigated. Microstructure analysis on specimens with a different reduction ratio supported by 2D-drawing process simulation using DEFORMTM was utilized to examine the deformed state and microstructure behavior of the alloy. Dynamic recrystallization (DRX) phenomenon on the high reduction ratio (52.7%) was achieved fine equiaxed grain. A Zenner-Holllomon calculation using temperature and strain rates was also conducted to evaluate the DRX. Furthermore, a higher drawing reduction ratio attributed to a high fraction of kinked lamellar, which DRX occurred in the shear band and the regions of broken lath or kinked.
Effect of Strontium Addition in Graphite Morphology and Nodularization of Hypoeutectic Cast Iron
Authors: Rahmadi  , Ferdian Deni
Published: July 2020

Nodular graphite cast iron or known as spheroidal graphite cast iron structurally has a spherical graphite morphology with a matrix consisting of a ferrite-pearlite phase. In general, cast iron has a main alloy consisting of carbon and silicon where both elements have an influence on the potential of graphitization and castability. In this work, the influence of strontium (Sr) added to molten cast iron with a composition of 0, 0.04, 0.06 and 0.08 wt% to graphite morphology were studied. The sample obtained will be carried out a characterization process by observing macro and microstructures using optical microscope equipped with image data processing software that displays graphite fraction, size, form and nodularity. Analysis showed that Sr addition increase in nodularization of graphite from 19.6 % to 31.5% at 0.08 wt% Sr addition.
Narrative Stories of High Risk Sexual Behaviors among Adolescents in Makassar City
Authors: Ibnu Indra Fajarwati , Wahjuni Chatarina Umbul , Devy Shrimarti Rukmini
Published: July 2020

Background

Dating behavior by some Indonesian adolescents is against the social norms of the society, showing moral gaps and psychosocial unconventionality. Several challenges emanate from this issue, including risk behavior-sexual intercourse. This research aims to describe the adolescents’ risk behavior-sexual intercourse in Makassar City.

Design and methods

The study uses a narrative qualitative approach with a criterion sampling technique. Three adolescents who participated in this research: two males and one female, between 17 and 19 years of age. The data are obtained through an in-depth interview based on the guideline from to Adolescent Health and Development Questionnaire by Jessor.

Results

The result shows that risk behavior such as premature sexual intercourse is caused by high risk factors, including behavior, opportunity, models, and vulnerability risks. The moderator effect of protection form protective factors, such as behavior, controls, models protection and supports protections toward risk factors, play less significant roles in minimizing the possibility of indulging in risk behavior in sexual intercourse and in dating.

Conclusions

The risk of sexual intercourse starts from dating, which leads to sexual intercourse. Additionally, this issue is also attributed to the risk and protective factors, affecting preparation for adulthood, personal development, and health.
Recovery Time Period and Quality of Life after Hysterectomy
Authors: Afiyah Raden Khairiyatul , Wahyuni Chatarina Umbul , Prasetyo Budi , Dwi Winarno Didik
Published: July 2020

Background

Women who had undergone hysterectomy have to overcome problems related to sexual and reproductive health. They often suffer a decline in self-esteem due to sexual dysfunction and the inability to give birth, along with their quality of recovery. This study aims to describe the relationships between recovery time and the components of quality of life after hysterectomy.

D esign and methods

103 women post-hysterectomy from several community-integrated health center in Surabaya were selected using the total sampling technique.

Results

Findings show that there is relationship between recovery time period and sexual activity (P=0.000). However, no significant relationship exists between recovery time period personal relationships and social support.

Conclusions

It is recommended that nurses should improve their social support for women and families during recovering, to avoid pathological stress and improve quality of life.
Reinforcement of Human Resources in Implementing Healthy Indonesian Program with Family Approach
Authors: Widiarini Retno , Chalidyanto Djazuly , Rusdianah Eva
Published: July 2020

Background

The Healthy Indonesia Program is a government program implemented with the Family Approach (HIP-FA) through a survey on healthy families. However, the quality of the program depend on the performance of the Human Resources (HR). This study aims to examine various aspects of HR in implementing the program at health centers.

Design and methods

Data were collected through in-depth interviews, Focus Group Discussions, and document review on eight informants at the Health Office center.

Results

Four themes revealed from the study: being burdened, feeling overwhelmed, feeling incompetent, and confused managing technology. The results showed that the implementation of the HIP-FA survey is an additional burden for health center staff.

Conclusions

It is necessary to strengthen the implementation of all programs through continuous training and education, positive affirmation, recalculating employee workload and remunerations.
Evaluating the Safe Use of Antidepressants in Older Adults: A Case-Based Approach
Authors: Wong Elaine , Nguyen Timothy V.
Published: July 2020

Depression in older adults is a mood disorder associated with physical and/or cognitive impairment. Though it may be present in a variety of settings, depression is a prominent health concern among long-term care and nursing facility residents. Pharmacologic therapy may be considered
in patients with depression who have not responded to nonpharmacologic therapy or are experiencing considerable disability. There are a variety of commonly prescribed antidepressant drug options for this indication. Examples may include selective serotonin reuptake inhibitors, serotonin norepinephrine
reuptake inhibitors, or serotonin modulators. As the use of these agents continues in older adults, senior care pharmacists should be familiar with the evaluation of its safe and combined use (e.g., drug interactions, adverse effects).
Description of Pharmacist Recommendations in the Caring for Older Adults and Caregivers at Home (COACH) Program
Authors: Melville Brittany Loy , Bailey Janine , Moss Jason , Bryan William , Davagnino Judith , Twersky Jack , Pepin Marc
Published: July 2020

OBJECTIVE: To describe recommendations made by geriatric clinical pharmacists within an innovative care model focusing on patients with dementia living at home. DESIGN: Retrospective chart review. SETTING: Outpatients in a tertiary care Veterans Affairs health care
system. PARTICIPANTS: Veterans who underwent a Caring for Older Adults and Caregivers at Home (COACH) Program assessment and had at least one medicationrelated recommendation made by a geriatric clinical pharmacist. MAIN OUTCOME MEASURES: The primary endpoint was the number and
category of medication-related recommendations made by a geriatric clinical pharmacist at the initial COACH program assessment. Secondary endpoints were recommendation acceptance rates and change in potentially inappropriate medications (PIMs) at six months. RESULTS: There were 104
patients included. The mean age was 81 years and the majority of patients were male and Caucasian. At baseline, patients were receiving a mean of 12 medications/person, and 59% of patients were receiving at least one PIM. There were 248 total medication recommendations made, with a mean of
2.4 recommendations/person (range 1-5). The three most common recommendation categories were to discontinue a drug, decrease the dose, and switch to a potentially safer alternative. Providers accepted 110 (44%) recommendations within six months. Patients were receiving a mean of one PIM/person
at baseline, and no change was observed at six months.CONCLUSION: This study describes recommendations made through medication reviews by geriatric clinical pharmacists within an innovative care model for patients with dementia living at home. These data may provide information to other
clinical pharmacists implementing consult services in similar settings.
A Reverse-Engineering Method for Powertrain Parameters Characterization Applied to a P2 Plug-In Hybrid Electric Vehicle with Automatic Transmission
Authors: DiPierro Giuseppe , Galvagno Enrico , Mari Gianluca , Millo Federico , Velardocchia Mauro , Perazzo Alessandro
Published: July 2020

Over the next decade, CO2 legislation will be more demanding and the automotive industry has seen in vehicle electrification a possible solution. This has led to an increasing need for advanced powertrain systems and systematic model-based control approaches, along with additional complexity. This represents a serious challenge for all the OEMs. This paper describes a novel reverse engineering methodology developed to estimate relevant powertrain data required for fuel consumption-oriented hybrid electric vehicle (HEV) modelling. The estimated quantities include high-voltage battery internal resistance, electric motor and transmission efficiency, gearshift thresholds, torque converter performance diagrams, engine fuel consumption map and front/rear hydraulic brake torque distribution. This activity provides a list of dedicated experimental tests, to be carried out on road or on a chassis dynamometer, aiming at powertrain characterization thanks to a suitable post-processing algorithm. In this regard, the methodology was applied on a P2 Diesel Plug-in HEV equipped with a 9-speed AT. Voltage and current sensors are used to measure the electrical power exchanged between battery and electric motor; a torque sensor on the propeller shaft measures the total torque coming out from the automatic transmission. The hydraulic pressures in the four brake calipers are measured and CAN data is logged. The results of the testing campaign are then presented and discussed. Functional models of powertrain subsystems are introduced and their parameters estimated using least square method. The good match between models and experimental data proved that the proposed methodology, if properly adapted to the specific layout, is a suitable tool for powertrain parameter estimation.
Identification of Automotive Cabin Design Parameters to Increase Electric Vehicles Range, Coupling CFD-Thermal Analyses with Design for Six Sigma Approach
Authors: Piovano Andrea Alessandro , Scantamburlo Giuseppe , Quaglino Massimo , Gautero Matteo
Published: July 2020

The ongoing global demand for greater energy efficiency plays an essential role in vehicle development, especially in the case of electric vehicles (EVs). The thermal management of the full vehicle is becoming increasingly important, since the Heating, Ventilation, and Air Conditioning (HVAC) system has a significant impact on the EV range. Therefore the EV design requires new guidelines for thermal management optimization.

In this paper, an advanced method is proposed to identify the most influential cabin design factors which affect the cabin thermal behavior during a cool down drive cycle in hot environmental conditions. These parameters could be optimized to reduce the energy consumption and to increase the robustness of the vehicle thermal response.

The structured Taguchi’s Design for Six Sigma (DFSS) approach was coupled with CFD-Thermal FE simulations, thanks to increased availability of HPC. The first control factors selected were related to the thermal capacity of the panel duct, dashboard, interior door panels and seats. Surface IR emissivity and solar radiation absorptivity of these components were then added to the study. Car glass with absorptive and reflective glazing were finally included in the study. The design space of 18 vehicle configurations was simulated in spring and hot summer conditions, with steady state thermal simulations. A 2-step optimization was then conducted, trying first to increase the robustness of the cabin response and, secondly, to reduce the equivalent temperature actually felt by passengers. The Verify phase was then conducted on the Best Engineering design emerged by the 2-step optimization, through quasi-transient CFD-Thermal FE analyses. The thermal results were then sent to a CFD 1D energy prediction model, confirming the HV battery energy saving and the extended range reached during the cool down drive cycle.
Sistema de Lector Óptico de Marcas (OMRS) con el uso de Escáneres de Imágenes basados en web.
Authors: Kamil Dimililer  , Getinet Amare Mekonnen.
Published: July 2020

El documento propone un nuevo sistema utilizando técnicas de procesamiento de imágenes. El sistema tiene ocho tipos de hojas de puntuación y su propio código de barras para clasificarlas. La hoja de puntuación contiene 15, 20, 30, 45, 60, 80, 100 y 125 preguntas con 5 opciones en cada una. Este sistema tiene dos tipos de usuarios: el primero es un alimentador y puede ver el resultado OMR, y el segundo ve resultado OMR. El sistema envía la hoja de calificación reconocida al delimitar el área de respuesta con diferentes colores: el verde para respuestas marcadas correctamente, el rojo para respuestas marcadas duplicadas y el amarillo para las preguntas sin marcar. Los resultados muestran que el sistema toma hojas de calificación y produce resultados con calificación de letras y letras numéricas equivalentes.
Evaluar los riesgos de utilizar los principios de la ingeniería de valor en la implementación de proyectos civiles.
Authors: Youssef Nikfard  , Mahdi Baniasadi.
Published: July 2020

En este artículo, intentamos evaluar los riesgos más importantes de la aplicación en proyectos civiles y priorizarlos en función de los riesgos identificados, y luego proporcionar soluciones para abordar estos riesgos. Los resultados de la investigación muestran que los seis factores principales (1) los factores generales, (2) los factores de la ley, (3) los factores estructurales, (4) los factores del campo de los asesores, (5) los factores de la fase de los estudios preparatorios y (6) los factores de la fase de los estudios de ingeniería de valor, se consideran como los principales riesgos identificados en la aplicación de la ingeniería de valor en proyectos civiles.
Sobre la cuestión del texto de Karlsbad en la poesía rusa.
Authors: Nikolay L. Vasilyev  , Dmitry N. Zhatkin.
Published: July 2020

El artículo comprende la autoría de un poema anónimo «La vida salvaje que llevamos en Karlsbad ...», distribuido en Rusia en las listas a mediados del siglo XIX. En el proceso de estudio, utilizamos métodos socioculturales, comparativo-históricos e histórico-tipológicos de investigación, así como métodos de análisis comparativo. Los autores exponen la idea de que este trabajo lúdico está escrito por P.A.Vyazemsky, lo que se confirma con los nuevos datos de archivo.
Acerca del problema de enseñar a estudiantes de universidades médicas a resolver problemas de biofísica.
Authors: Olga V. Ivanchuk.
Published: July 2020

El estudio aborda el problema de enseñar a los estudiantes de las universidades médicas a resolver problemas de biofísica, en particular a formar los métodos para resolver problemas de biofísica entre los futuros médicos. Se presta especial atención a la necesidad de un trabajo especialmente organizado para la asimilación de actividades dirigidas al desarrollo de modelos matemáticos de problemas y su resolución con el uso de aparatos matemáticos avanzados. En este sentido, los tipos de problemas se establecieron de acuerdo con los métodos aplicados de análisis matemático y se identificaron sistemas de acción generalizados para desarrollar el modelo matemático de estos tipos.