bluuebunny/crossref_metadata_2025 huggingface dataset:
Broadband single‐layer reflectarray antenna for X‐band applications
Authors: Bodur Hande , Ünaldı Sibel , Çimen Sibel , Çakır Gonca
Published: March 2018

A new type of X‐band (8–12 GHz) unit cell structure on a single‐layer for broadband reflectarray antennas is presented in this study. To obtain a broadband performance, a unit cell composed of a circular ring and a complementary diagonal patch ring is proposed. This new type unit cell is designed on a 0.183 × λ0 (air‐dielectric) thin dielectric substrate and has a 430° phasing range with slow phase variation. Based on the wide phase variation of the proposed unit cell, a centre‐fed broadband reflectarray antenna is designed with 9 × 9 unit cells, 81 elements on a square plane geometry. The designed reflectarray has 40% aperture efficiency and 96% antenna efficiency at 10.5 GHz. The validity of the reflectarray antenna is verified through measurement and simulation results. The experimental and simulation results are in good harmony. The measured and simulated results show that the maximum gain of the reflectarray antenna is 21.6 dBi at 10.5 GHz and has 23% 1 dB gain bandwidth and 29% 3‐ dB gain bandwidth. Also, the minimum cross‐polarisation discrimination is 31.2 dB at 11 GHz frequency.
Selective harmonic elimination in multilevel inverter using hybrid APSO algorithm
Authors: Memon Mudasir Ahmed , Mekhilef Saad , Mubin Marizan
Published: March 2018

This study presents selective harmonic elimination pulse width modulation technique‐based hybrid asynchronous PSO‐Newton‐Raphson (APSO‐NR) algorithm for the elimination of undesired harmonics in cascaded H‐bridge multilevel inverter. The proposed algorithm is applicable to all levels of MLI having equal and non‐equal DC sources. In the proposed method, ring topology‐based APSO algorithm is hybrid with NR method. APSO worked as a global search technique and NR is used for the refinement of best solutions. APSO‐NR is applied to the seven‐level inverter to eliminate fifth and seventh harmonics. In simulations, the performance of the proposed algorithm is compared with genetic algorithm, bee algorithm and particle swarm optimisation. The results proved that the proposed algorithm is efficient, and gives more precise firing angles in less number of iterations with high capability of tackling local optima. For the 48% of modulation index range, APSO‐NR minimised the fitness function value lower than (10−25). The proposed algorithm is validated through the experimental implementation of the three‐phase seven‐level inverter.
Stacked dielectric patch resonator antenna with wide bandwidth and flat gain
Authors: Sun Wen‐Jian , Yang Wen‐Wen , Tang Hui , Chu Peng , Chen Jian‐Xin
Published: March 2018

A stacked dielectric patch resonator antenna with wide bandwidth and flat gain is proposed. For this design, two thin ceramic sheets with high permittivity are introduced to operate as approximate magnetic walls. Incorporated with another ground plane, two resonant modes can be excited to form a wide bandwidth, and a flat gain is also achieved within the band. Measured results demonstrate that the antenna obtains an impedance bandwidth of 18.2% and an average gain of 7.2 dBi.
Fabrication and application of porous Pd@Mt/PC composite as an efficient green heterogeneous catalyst for Suzuki cross‐coupling reaction
Authors: Tian Li , Yunlong Sun , Rui Zhou , Mudi Long , Yufan Liu
Published: March 2018

The palladium‐loaded montmorillonite (Pd@Mt) was mixed with polycarbonate (PC) solution to obtain Pd@Mt/PC composite. A different solvent was used to treat the Pd@Mt/PC coating so as to induce crystallisation of PC and fabricate a porous surface. The scanning electron microscopy and surface area measurement results proved this successful change. The Pd@Mt/PC that was treated by isopropanol fabricated a porous surface coating on glass microsphere (Pd@Mt/PC‐M), which was found to be a conveniently obtained environment‐friendly catalyst in the Suzuki reaction, as the Pd content was only 0.2012 ppm in the product solution. Notably, it exhibited high efficiency, affording the corresponding product in good to excellent yields for 20 reactants (in the range of 78–99%, only two reactants gained yield below 90%). As a heterogeneous catalyst, it could be easily recovered by simple filtration from the reaction mixture and a high yield of more than 90% at a third run was remained.
Structure, magnetic and microwave studies of mechanically alloyed powders Fe45Ni35Co20
Authors: Haddad Ahmed , Ouldbrahim Insaf , Azzaz Mohamed
Published: March 2018

Nanocrystalline Fe‐35 wt%Ni‐20 wt%Co has been prepared by using a high‐energy planetary ball mill with increasing milling time from 4 to 36 h. Microstructural characterisations showed the development of an face‐centred cubic nanostructured Fe‐35 wt%Ni‐20 wt%Co alloy with an average crystallite size of 8 nm. The magnetic investigation revealed that the nanostructures obtained from a milling time of 36 h have the highest magnetic saturation and the lowest coercive field. In addition, the hardness and the electromagnetic absorption of the Fe‐35 wt%Ni‐20 wt%Co alloy were found to increase with the milling time. These evolutions could be attributed to the crystallite size and the strain variations in the samples during milling.
Multistep synthesis of AgBr quantum dots coupled porous BiOBr spheres for enhanced photocatalysis
Authors: Qi Rui‐Juan , Yang Li‐Xia , Yi Chen‐Yu , Hang Chun‐Liang , Liu Qian
Published: March 2018

A three‐step route has been adopted for the synthesis of AgBr quantum dots coupled porous BiOBr spheres. Firstly, porous Bi spheres were obtained through a simple solvothermal method employing ethylene glycol as a reducing agent. Sequentially, a redox reaction of Bi spheres with NH4 Fe(SO4)2 as an oxidiser was employed to prepare porous BiOBr spheres. Finally, AgBr quantum dots were loaded on BiOBr spheres through in situ precipitation. The obtained powders were characterised by employing powder X‐ray diffraction for phase confirmation and transmission electron microscopy for microstructure evolution. BiOBr hierarchical spheres with a diameter of ca. 500 nm were made up by two‐dimensional nanosheets. AgBr quantum dots were deposited on BiOBr petals and did not influence the microstructure and morphology of the BiOBr host. The BiOBr/AgBr composite exhibited higher photocatalytic activity than pure BiOBr porous spheres in degrading Rhodamine B dyes.
Alternating and semicontinuous chemical reduction method for high production of silver nanoparticles
Authors: Pedroza‐Toscano Miguel A. , Lopez‐Cuenca Susana , Moreno‐Medrano Edgar D. , Rabelero‐Velasco Martin , Salazar‐Peña Rodolfo
Published: March 2018

Synthesis of silver nanoparticles (AgNPs) was carried out in aqueous solutions. Silver nitrate was used as precursor, carboxymethyl cellulose (CMC) as stabilising agent, and sodium borohydride as reducing agent. The reaction was semicontinuous by feeding both the precursor and reducing agent into the stabilising agent aqueous solution in an alternated fashion. Weight ratios of 1:1 AgNO3 :CMC were used in the reduction reactions. AgNPs were characterised by UV–vis spectroscopy, transmission electronic microscopy (TEM), and X‐ray diffraction. The formation of AgNPs was confirmed by the presence of an absorption peak about 400 nm using UV–vis spectrophotometry. Spheroidal nanoparticles with an average diameter between 5 and 90 nm were observed by TEM. High productivity of AgNPs was obtained at lower reaction times and at low temperature compared with others previously reported in the literature.
Housing Typology of Bali Aga Architecture in Sukawana Village: Developments and Challenge
Authors: Yudantini Ni Made , Surya Darma Kadek Agus
Published: March 2018

The Bali Aga is an Indigenous people of Bali scattered in remotes areas such as mountains, hills, along the Batur Lake, and highlands. The Bali Aga people still practices the original tradition and differ from other Balinese people who mostly live in mainland area which differentiated by the reign of Majapahit Kingdom. Bali Aga refused Majapahit’s influences, in contrast other Balinese followed the Majapahit rules that known as Bali Apanaga. Bali Aga still conserves original tradition but cannot avoid the increasing of development in technology and communication. Sukawana Village is one of Bali Aga village still conserve the Indigenous culture and tradition that located in highland of Kintamani Regency. The research aims to seek how the people adhere the tradition, norm, and values; and to explore the housing typology in Sukawana Village that faces on influence of development and threaten by globalization. The research primarily involves a qualitative method with includes an extensive literature review regarding the Bali Aga village and its distribution in Bangli Regency. The field research collected data through on-site evaluation and observation in Sukawana Villages in 2017, interviews to village leader and randomly questions to the householders. The research finding is the changing occurred in Sukawana Village such as using of new material and changes of indoor housing pattern.
On the Sound Absorption Improvement of Water Hyacinth and Coconut Husk based Fiber Reinforced Polymer Panel
Authors: Setyowati Erni , Yahya Iwan , Supriyo Edi , Romadhona Intan C. , Minardi Aris
Published: March 2018

This paper emphasizes on the sound absorption improvement of the water hyacinth and coconut husk based fiber reinforced polymer (FRP) panel. The dry water hyacinth and coconut husk were milled and sieved before it mixed with polyester and methyl ethyl ketone peroxide as the catalyst. The composition is 200 ml, 25 grams, and 20 ml for the polyester, fiber, and catalyst respectively. The mixture casting is by using a square tray to form a flat FRP panel through open air drying without any compaction process. Three different approaches i.e. multiple quarter wavelength resonators, air cavity, and front fibrous layer inclusion are implemented to the FRP to improve its sound absorption performance. The entire measurements conducted by using transfer function based impedance tube technique refer to ASTM E-1050-98 standard. B&K 4206. It found that the proposed approaches are increase sound absorption coefficient of the bulk FRP significantly. The best performance occurred on the coconut husk based FRP when the 8 of quarter wavelength resonators combined with the fibrous layer. Sound absorption increased accordingly to above of 0.7 starting from 1.5 kHz. On the other side, the air cavity shows similar influence on the entire test sample due to Helmholtz resonance mechanism.
Development of Back-calculation Model for Aggregate Gradation Determination Using Fractal Theory
Authors: Hario Setiadji Bagus , Supriyono  , Purwanto Djoko
Published: March 2018

Several studies have shown that fractal theory can be used to analyze the morphology of aggregate materials in designing the gradation. However, the question arises whether a fractal dimension can actually represent a single aggregate gradation. This study, which is a part of a grand research to determine aggregate gradation based on known asphalt mixture specifications, is performed to clarify the aforementioned question. To do so, two steps of methodology were proposed in this study, that is, step 1 is to determine the fractal characteristics using 3 aggregate gradations (i.e. gradations near upper and lower bounds, and middle gradation); and step 2 is to back-calculate aggregate gradation based on fractal characteristics obtained using 2 scenarios, one-and multi-fractal dimension scenarios. The results of this study indicate that the multi-fractal dimension scenario provides a better prediction of aggregate gradation due to the ability of this scenario to better represent the shape of the original aggregate gradation. However, careful consideration must be observed when using more than two fractal dimensions in predicting aggregate gradation as it will increase the difficulty in developing the fractal characteristic equations.
Interval Confinement in Compression Zone to Evaluated Beams Performance Subjected Monotonic Loads
Authors: Priastiwi Yulita Arni , Imran Iswandi , Nuroji  , Yuniarto Adi Rudi
Published: March 2018

Confinement is one way that can be used to improve the performance of reinforced concrete structures, mainly related to ductility. The parameter of the distance between the confinement becomes an important thing that must be studied its effect on ductility produced by a structural element. This study aims to study the effect of different distance between the confinement in compression zone in the beam at the plastic hinge area to the displacement and the behavior of the beam when it was given monotonic loading. The specimen model which is a simplified form of the plastic hinge area up front column will be fitted with a confinement in the compression zone which is attached to the shear reinforcement with different distances of 0, 70, 125 mm. Also made a beam with a crossties confinement spaced 125 mm for comparison. The presence of a centralized load in the middle of the span is intended to obtain the largest moment and shear areas in the plastic hinge. The test results showed that the installation of 125 mm intervals for confinement in the compression zone resulted in a higher ductility of 11-18% against the beam without confinement than the 70 mm interval which only increased by 2.78%. The hoops confinement produces higher ductility than crossties confinement for the same confinement interval. The increased confinement interval from 70 to 125 mm not yet significantly affect the moment capacity of the beam and the collapse was still dominant in the bending collapse although the distance between the stirrups and the confinement was slightly widened.
Development of risk-based standardized WBS (Work Breakdown Structure) for quality planning of high rise building architectural works
Authors: Rianty Mirradewi , Latief Yusuf , Riantini Leni Sagita
Published: March 2018

Work Breakdown Structure (WBS) is a breakdown of project work into smaller components so it can be better managed. Although each project is unique, most buildings can be standardized in their activities to enable the provision of a stronger forecast for project management. Quality performance is also important to be controlled and risk consideration approach is now required for overall quality management process in the updated ISO 9001. Therefore, the development of risk-based WBS for quality planning is proposed. The objective of the study was to develop risk-based WBS for high-quality building architectural works. The research consisted of several stages with qualitative risk analysis method. The result indicates that standardized WBS consists of 5 primary levels and 2 complementary levels, with 14 dominant risk variables on quality performance, and recommended risk responses as the development.
Components of Indonesian Traditional Market: Design Tools for Revitalisation
Authors: Hermawan Ferry , Indarto Himawan , Ismiyati
Published: March 2018

The lesson learnt of revitalization of market buildings is still a dilemma for traders as the main actors of traditional Indonesian market life. The root of the revitalization issue has not been properly mapped objectively, due to the complex role of the stakeholders involved in it. This research uses case study method with a qualitative approach by semi-structured interviews and observation of typology of Indonesian traditional market activities in five metropolitan cities of Java. This study uses four samples of traditional markets, one in Jakarta and three revitalized markets in Semarang. The mapping of the component is composing by field observation and Focus Group Discussion (FGD) with a civil engineer and two architects. The results of this study obtained justification that the revitalization of traditional Indonesian market if mapped components are factors that affect the success or failure of a revitalization process when compared to some case studies of market revitalization in Jakarta and Semarang. This research suggests to the local decision makers to avoid the paradigm of budget-based development but, also to adapt socio-engineering aspects by considering the social interaction of traditional market traders in the Indonesian context.
Indonesian Highway Capacity Guidance (IHCG) correction factor for signalized intersection
Authors: Indriastuti Amelia K. , Yulipriyono Eko
Published: March 2018

Indonesian Highway Capacity Guidance or IHCG is a manual developed in 2014 to accommodate traffic characteristics which are no longer appropriate to the preceding manual (Indonesian Highway Capacity Manual or IHCM, established in 1997). From a preliminary study, there are still some differences between theoretical analysis (using IHCG) with the actual conditions. This study aims to obtain IHCG correction factor based on a comparison between predicted performance parameter of a signalized intersection (using IHCG) and measured data, in order to optimize IHCG development. Intersection performance parameters analyzed are the number of queue vehicles (NQ1 and NQ2), and queue length (QL). The model of the correction factor was determined with regression analysis, using DS value as the independent variable, and NQ1, NQ2, or QL differences value as the dependent variables. Implementation of the proposed correction factor of queue length on nearby intersections resulted that the corrected guidance could produce more accurate queue length against measured one by 12% deviation.
Green House Gases (GHG’s) Emission Reduction Measures and Verification Challenge at Transport Sector
Authors: Huboyo Haryono , Wibowo Hari , Retna Sari Winda
Published: March 2018

The Ministry of Transportation Republic of Indonesia adopted several co-benefits activities related to climate change mitigation action through 2010-2014. In order to claim these activities results as climate change mitigation action, Ministry of Environment and Forestry need to verify them. The verification covers data accuracy, consistency, transparency and completeness of data quality and information. The author also verify the other parameters such as the calculation method, managerial system, monitoring system and funding support. In this program, several mitigation actions were implemented such as Area Traffic Control System (ATCS), traffic impact control, parking management, Bus Rapid Transit (BRT) system, smart driving, non-motorized transport, shifting from private vehicles to rail transport, rejuvenating of navigation facilities, aircraft fleet rejuvenation, renewal of the operation and maintenance system of airplane and improvement of flight navigation system during take-off and landing. The absolute difference results between claim and verification for all climate change mitigation actions based on Government Regulation (PP) No. 61/2011 were 13.44% - 43.5%. While for mitigation action beyond PP 61/2011, the absolute difference were 0% - 67.31%. There are no mitigation action satisfying all verification criteria. Based on these verification activities, The Ministry of Transportation should refine the method of mitigation action.
Recovery Practice of Unsorted Solid Waste: from Landfill towards Economic Benefits in Semarang, Indonesia
Authors: Arief Budihardjo Mochamad , Fajarini Sri Wahyuningrum Indah
Published: March 2018

The field study in Jatibarang landfill in Semarang was conducted by quantifying the solid waste that had been collected and transferred to the landfill to obtain the amount of the solid waste generated by the residents of Semarang. The gross weight of the waste was calculated by randomly selecting and weighing the shipments on the scale before the load was dumped by the vehicle. The solid waste received by Jatibarang landfill is about 651.5 tons per day, with a density of 245 kg/m3. The composition of domestic waste in Jatibarang landfill is 77.7% organic waste, 14.19% plastics, 5.31% mixed paper, and 1.36% others. The inorganic wastes in Jatibarang landfill still retain economic value of IDR 141 million per day when fully recovered. The current recovery practices are performed by scavengers who live in the surrounding area of Jatibarang landfill.
Methane enrichment on biogas generated from anaerobic digester using coconut shell-based activated carbon
Authors: Hakim Ridwan , Suwartha Nyoman , Priadi Cindy
Published: March 2018

This study evaluates methane enrichment on biogas generated from Anaerobic Digester (AD) through CO2 adsorption process so that biogas can be used as fuel for vehicle engines, power plants, and natural gas substitutes. The experiment was observed by passing biogas synthesis (45% CH4 + 55% CO2) and biogas from cattle manure ±59.7% CH4, ± 37.1% CO2 and ±3.2% other gases) in spontaneously pressurized adsorption column. In addition, observation of CO2 adsorption capacity at various pressure and fixed temperature (27°C) was performed using pure CO2 (±98%). Methane in biogas has been successfully purified to 92% at 0.5 L/min flowrate and 79.6 seconds retention time. The adsorbent will be saturated after gas flowing for 60 and 80 minutes for synthesis biogas and biogas from AD on the amount of adsorbent of 266 grams. A change of surface area of activated carbon (AC) after thermal regeneration at 160°C for 2 hours was 7.51% and regeneration efficiency was 67%. The adsorption process followed Freundlich isothermal. This process can be feasible alternative technology to meet the need for biogas with high levels of methane in small-scale AD.
The analysis of volcanic activity influences at the lower and middle part of Sentolo Formation, Kulon Progo using petrographic method
Authors: Winarno Tri , Marin Jenian , Hani Pratama Ilham , Kurniasih Anis
Published: March 2018

The research area is a part of South Serayu Mountain zone, specifically Bregada Kulon Progo. The Bregada Kulon Progo is a product of volcanic activity in the past, which can be seen by the volcanic rock called Old Andesite Formation. The end of the volcanic activity is characterized by the deposition of carbonate rocks which were part of Jonggrangan Formation and Sentolo Formation. The lower part of Sentolo Formation is composed by the mix of carbonate and volcanic materials. The research is carried out by two methods. The first is field method, which is implemented by geological mapping and rock sampling. The second is laboratory method, which is implemented by petrographic method. The petrographic method is implemented by making thin section of the rocks, then observing the thin section with polarization microscope to determine the composition of the rocks. The rock samples are mainly from the lower and middle part of Sentolo Formation, which probably still got the influence of volcanic activity. The benefit of the research is knowing the influence of volcanic activity in the carbonate rocks of Sentolo Formation. The presence of volcanic materials in the lower part of Sentolo Formation, can be predicted by two processes. First, the volcanic activity supplied those materials directly, and second, from the rework of the volcanic materials then mixed with carbonat materials of Sentolo Formation.
Housing Satisfaction and Willingness to Move to Low-cost Rental Apartments of Slum Dwellers in Semarang Urban Area
Authors: Manaf Asnawi , Wahyono Hadi , Puspita Sari Ita , Aprilia Dias
Published: March 2018

This article examines one of the approaches commonly taken by the government to reduce the number of slums in urban areas, namely the provision of subsidised/affordable rental apartments. This article focuses on the assessment of to what extent the approach is relevant to the perceived problem (needs) of the target group (low income family) and what are the socio-economic characteristics of those living in slums and what are their preferences for moving to affordable rental apartments or remains to stay in the current slums. Since the problems are complex and dynamic, the case study research methods has been utilised and the low-income families living in slums in surrounding areas of Rusunawa Kaligawe (affordable rental apartment) in Semarang have been used as the unit of analysis.
Simulation and analysis of the aeroelastic-galloping-based piezoelectric energy harvester utilizing FEM and CFD
Authors: Haryanto Ismoyo , Widodo Achmad , Prahasto Toni , Satrijo Djoeli , Pradiptya Iswan , Ouakad Hassen
Published: March 2018

Due to a large oscillation amplitude, galloping can be an admissible scenario to actuate the piezoelectric-based energy harvester. In the case of harvesting energy from galloping vibrations, a prismatic bluff body is attached on the free end of a piezoelectric cantilever beam and the oscillation occurs in a plane normal to the incoming flow. The electrical power then can be extracted from the piezoelectric sheet bonded in the cantilever structure due to the dynamic strain. This study is proposed to develop a theoretical model of a galloping-based piezoelectric energy harvester. A FEM procedure is utilized to determine dynamic characteristics of the structure. Whereas the aerodynamic lift and drag coefficients of the tip bluff body are determined using CDF. The results show that the present method gives precise results of the power generated by harvester. It was found that D-section yields the greatest galloping behavior and hence the maximum power.
Analysis of calcium carbonate polymorphs deposited in water piping system and the effect of tartaric acid additive
Authors: Putranto W. A. , Umardhani Y. , Sulistyo  , Yurianto  , Bayuseno A. P.
Published: March 2018

Calcium carbonate (CaCO3) formed in a water piping system was investigated in the presence of chemical additives tartaric acid (0.00 and 10.00 ppm) and various temperatures ((27 and 50ºC). The flow rate inside pipe (35 ml/min) were selected. Solutions of CaCl2 and Na2CO3 were prepared in water with equimolar to Ca2+ concentration of 3000 ppm. The induction time of scale nucleation varied from 24 min to 44 min. An increasing temperature of the solution resulted in more CaCO3 scale, mass, while the higher tartaric acid made the reduced mass of scales by 90%. SEM/EDS analysis verified CaCO3 with a plate like morphology. Also the XRPD Rietveld method provided the confirmation of a major phase of calcite and vaterite minerals followed by the minor of aragonite in the absence of tartaric acid and at room temperature. However, the presence of 10 ppm tartaric acid yielded the increasing result of calcite, while aragonite precipitation was hampered under the influence of tartaric acid. The presence of tartaric acid at increasing temperature of 50ºC could delay formation of calcite, whereas aragonite could be formed significantly. Thus the study showed the capacity of the tartaric acid in influencing CaCO3 crystallization.
Resistance and Stability Analysis for Catamaran Fishing Vessel with Solar Cell in Calm Water
Authors: Putranto Teguh , Aryawan Wasis Dwi , Kurniawati Hesty Anita , Setyawan Dony , Pribadi Sri Rejeki Wahyu
Published: March 2018

The use of solar cell as the moving force for the ship's tour seems to be an important theme in action to create a sea transportation that is environmentally friendly as contribution of the Energy Efficiency Design Index (EEDI) for the decrease of pollutant levels. The electrical energy produced by solar cell is not as much energy from fuels so that the solar energy powered ship that can only be followed with a limited range and speed. This type of multi hull design like catamaran that has two symmetrical hull which is possible to have an more expansive main deck, small boat boundaries and good stability. The ship deck shape is going to contribute the extension of solar panels that can be used as a generator of power needed at the time of calculation of powering the ship. The analysis of the stability of the ship carried out numerically bu using references from the IMO regulations which require minimum value stability arm at certain angles. Load cases are definitely varied in 2 (two) conditions and compared in full and light load. The goal of this research is catamaran fishing vessel that have battery, solar panel, electric motor and all of supporting solar energy moving with speed 5 knots.
Porosity Control and Mechanical Properties of Porous Ceramic Material from Plered Region
Authors: Sulistyo S. , Rizky
Published: March 2018

Plered region is located in around Purwakarta area, west java, Indonesia. Plered is famous as ceramic product especially ceramic tiles, decorative ceramics, tableware and roof tiles. This paper investigated the manufacturing of porous ceramic from Plered and evaluated the mechanical properties especially bending strength. The investigation include the controlling of porosity using pore former during manufacturing, investigation of chemical composition and evaluated the fracture strength using bending test. Evaluation of porosity ceramic product use an archimedes method and scanning electron microscopy and the bending strength of porous ceramic using three point bending test. The porous ceramic was tailored by using compaction process and sintering process at temperature of 1250 C, the pore former (rice starch) was added on the material ceramic to control of porosity. The bending strength use standard ASTM C1161-13 which sample has cross section of 6x8 mm2 and 90 mm long. The results show that the porosity increases with the number of pore formers in a mixture of clay, the porosity of sinter ceramic was 7 vol%,12 vol%, 17 vol% at using pore former 5 wt%, 15 wt% and 25 wt % respectively. The bending strength of sinter ceramic was declined with increasing porosity. The bending strength of sintered ceramic was 58 MPa, 49.5 MPa and 34.7 MPa at porosity of 7 vol%, 9 vol% and 14 vol% respectively.
Polyurethanization temperature effect to the thermal behaviour of cellulose – fiber based hybrid polyurethane
Authors: Kurnia Adi Herald , Hanum Ikhwan Fauzia , Aidilichsan Muliawan Hasyim , Chalid Mochamad
Published: March 2018

Polyurethanes are one of many types of polymers that are currently being developed worldwide. Some studies reported many substances involved in synthesizing polyurethanes (PU), with mostly originated from a biomass substance. Our laboratory has synthesized natural fiber – based PU to obtain hybrid PUs through varying reaction variables such as temperature. This study used cellulose, a biomass substance as well as polyethylene glycol and 4,4’ – methylenebis cyclohexyl isocyanate (HMDI) in synthesizing the hybrid PU, and investigated their thermal stability such as decomposition temperature by Differential Scanning Calorimetry (DSC) showed various tendency according to the chain extending temperature for the decomposition temperature. Simultaneous Thermal Analysis (STA) showed glass transition tendency of the product is proportional to the chain extending temperature, where the maximum glass transition obtained from the experimental is 59.8ºC at 70ºC of polymerization. Evaluation of functional group in the hybrid PUs was conducted with FT – IR spectroscopy measurement indicating urethane presence as part of the hybrid PUs.
Flame stability and behavior inside meso-scale combustor with different flame holder
Authors: Yuliati Lilis
Published: March 2018

Flame stability and behavior inside meso-scale combustor with different flame holder was investigated experimentally. Three types of flame holder i.e. wire mesh, flat plate with circular holes and flat plate with narrow slits, were used to improve the flame stability inside the meso-scale combustor. Combustor with flat plate - narrow slits flame holder has the best flame stability, i.e. stable flame established inside the combustor at the highest reactant velocity compared to the other combustor with the different flame holder. Furthermore, combustor with wire mesh and flat plate with narrow slits have a relatively uniform flame colour at the combustor cross section, compared to flame visualization inside meso-scale combustor with flame holder of flat plate with circular holes. This phenomena is related to non-uniform reactant distribution on the combustor cross section.
Performance Analysis of Sea Water Solar Still To Produce Fresh Water and Salt Using Flat Plate Collectors
Authors: Mulyanef  , Duskiardi  , Hidayat Rahmad
Published: March 2018

Fresh Water and salt are the most important necessities in human life. The scarcity and the difficulty to get fresh water and salt became main problems that emerge in many places such as for people who live in coastal areas and small islands where their main source of water and salt is the sea water. In order to obtain fresh water, people needs to process seawater into fresh water and salt. The term of fresh water used here means water which is free from dirt, bacteria, and other substances that are harmful for human health. To process the sea water into fresh water and salt has been done by distillation technic. The distillation technic requires heat to evaporate seawater before condensed and produce clean water. Heat for distillation process can be derived from a variety of sources, one of them is solar energy. The purpose of this study is to compare between a flat plate with one slope cover and two slope cover to produce fresh water and salt. The distilled water was tested in laboratory to determine whether the quality of water and salt after distillation meets the consumable requirements. The working principle of the distillator is by filled the basin with sea water and then heated with solar power. The water will be evaporated and due to the different of temperature between inside and out side of cover so that the condensation accurs at inside of cover. The condensed water will flow through surface of glass cover and then the distilled freshwater gathered in storage. The process will continue until water runs out and creates salt crystals in the basin. Solar distillation testing by using one slope cover with a size of 140 cm x 220 cm produce 3,482 ml / day of clean water and 322 grams of salt / 4 days at average intensity of 697 W/m2. While solar distillation by using two-slope cover with size of 80 cm x 50 cm produce 1,551 ml clean water/day and 199.9 grams of salt / 4 days.
The Influence of Guide Vane to the Performance of Cross-Flow Wind Turbine on Waste Energy Harvesting System
Authors: Santoso Budi , Danardono Dwi Prija Tjahjana Dominicus
Published: March 2018

The purpose of this experiment is to know the influence of a single guide vane position and angle to the performance of a cross-flow wind turbine. The cross-flow wind turbine was positioned at the discharge outlet of a cooling tower model to harness the discharged wind for electricity generation. A guide vane was used to enhance the rotational speed of the turbines for power augmentation. Various position and angle of attack of the guide vane were tested in this experiment. To avoid negative impact on the performance of the cooling tower fan and to optimize the wind turbine performance, the turbine position on the discharge wind stream was also studied. The result showed that cross-flow wind turbine with a guide vane attached at the right position had a higher coefficient of power than cross flow turbine without guide vane. A crossflow wind turbine with the guide vane at the position of 150 mm from the center and 30° angles had the highest coefficient of power of 0.49. Comparing to the wind turbine without guide vane, the coefficient of power of the cross-flow wind turbine was increased about 84.3%.
Surface Texture Influences on the Running-in Behavior and Friction Reduction
Authors: Hou Zhouyong , Honda Tomomi
Published: March 2018

For improving automobile fuel efficiency, the internal combustion engines must be required to reduce the friction and wear. Changing viscosity of lubricant and surface pressure could succeed, but the seizure is easy to happen in engines. However, the surface texture can solve those problems. The running-in behavior affects friction and wear on whole combustion engines. If the running-in is not carefully designed, catastrophic accident can happen. This experiment investigates that the running-in behavior is influenced by textured surfaces and the tested materials are the cast iron and the different area ratio of dimple of aluminum alloy combination. The friction coefficient and the number and size of wear particles are measured by the friction sensor and particle counter. After the tests, the worn surfaces are measured through using surface profile measurement systems, and some significant phenomena are observed and analyzed. The textured surface verifies good consequence and tribological advantages.
A study of tea leaves drying using dehumidification process and regeneration of liquid desiccant in a closed-cycle dehumidification-humidification
Authors: Yohana Eflita , Endy Yulianto Mohammad , Bahar Shofwan , Alifa Muhammad Azza , Laura Indrayani Novi
Published: March 2018

Tea plants in Indonesia are derived from Carmelia sinensis var. assamica which contain catechin in quite high amount compared with other countries tea plant. Green tea is made by inactivating the oxidase / phenolase enzyme that presents in the fresh tea leaf buds from tea garden, by using hot steam to prevent the oxidation of the catechins. Drying process to reduce the moisture of tea, one of the method is by utilizing the dry air from dehumidification process. Liquid desiccant made from 50% concentration of CaCl2, the temperature is lowered to 10 °C and sprayed into the air stream which contains water vapor by using a 0.2 mm spraying nozzle so that mass transfer and latent heat occur in the dehumidifier. The result of air dehumidification process used for drying tea leaves. The air is able to dry the tea leaves from the weight of 58 grams to 47 grams. Then the liquid desiccant dehumidification process will be streamed into the humidifier, where the liquid desiccant regeneration process will have change into the initial concentration. The result of air humidification process has an average absolute humidity rise of 0.07 g/kg. The liquid desiccant regeneration process that happened continuously reaching the saturation point at 280 minutes. It can be concluded that the process of dehumidification-humidification is a fairly effective method for drying the tea leaves.
Digital integrated instrument for measuring BMI and comparing to the ideal BMI for age as a guidance for Indonesian military recruitment
Authors: Basuki Wibowo Dwi , Ismoyo  , Suprihanto Agus , Caesarendra Wahyu , Ariyanto Mochammad
Published: March 2018

This study aimed to investigate body mass index (BMI) of 102 subjects to be Indonesian military officer candidates. To test the ideal body weight (IBW) used 2 methods for comparison, first from the calculation of IBW by Brodsky’s and modified Broca's formula and ideal BMI from WPRO criteria and second from IBW of the Indian Navy and TNI/POLRI recruitment. A digital integrated instrument for measuring BMI was manufactured where BW and body height (BH) are measured using loadcell and ultrasonic sensor respectively and the result is processed by Arduino Mega 2560 microcontroller. From the separate measurement results there are BW error 0.96%, BH error 3.22%, and BMI error 2.88% compared to using digitally integrated measurement.
CFD analysis on the aerodynamics characteristics of Jakarta-Bandung high speed train
Authors: Utomo Tony , Fajar Berkah , Arpriyanto Hendry
Published: March 2018

In this study, the aerodynamics characteristics of HST type CRH380A which is planned to be operated on the new railway of Jakarta-Bandung are analysed using Computational Fluid Dynamics. The speed of the train in this simulation was varied from 100 km/h to a maximum designed speed of 350 km/h with the increment of 30 km/h. The train was modelled in 3D computational domain with more than 1.7 million cells. The turbulence model employed in this study was standard k-ω. The simulation results show that the drag coefficient (CD) is slightly decrease by the increase of speed. At the speed of 100 km/h the CD is 0.216 and decrease to 0.188 at the speed of 350 km/h. The high pressure area is located at the nose of the train. The pressure acting on this location is increase with the increase of the train speed.
A Great Achievement of Calculated and Experimental Results of Char Kinetic Rate in Woody Mahogany Pyrolysis
Authors: Wijayanti Widya , Nur Sasongko Mega
Published: March 2018

In the pyrolysis process, it is needed to know the value of k (rate costant) to know the rate of reaction that occurs. It is needed to calculate k caused by T effect due to the reason that it is extremely difficult experimentally to find rate constants. The pyrolysis process was carried out for three hours with the minimum condition of Oxygen using mahogany wood. It was used the pyrolysis temperature variations of 250°C to 800°C. The results showed the increasing temperature and decreasing mass of char as long as the process to obtain, the kinetic rate of char k. We used two calculation approaches method to find the calc ulated k. Fristly, it used the total kinetic rate model equation with the equation kT = 60.3 e-2028.4/T and the second one, it was used the local kinetic rate model. In the local kinetic rate approached, it was divided the 3 temperature ranges; k1 in the range of 28°C - 250°C was k1 = 539.1 e-2907.3/T, k2 in the range of 250°C to 500°C was k2 = 27.11 e-1424/T; and k3 in the range of at range 500°C to 800°C was k3 = 572.4 e-4549.2/T. Then, by using the found k values, it was found the great achievement results that the decreasing mass of char in the calculation was coincide with the experimental results. It was used both kinetic rate methods depending on the required energy was needed in the pyrolysis process; at low pyrolysis temperatures, the appropriate kinetic rate model was a local kinetic rate model, and for pyrolysis at high temperatures of 600°C to 800°C, the accurate kinetic rate model was the total kinetic rate model.
Design of Fractal Features-Based Partial Discharge Pattern Recognition using Multi Support Vector Machine Method
Authors: Rahayu  , Anuraga G.T. , Prasetia H. , Khayam Umar
Published: March 2018

Partial Discharge (PD) is one of the causes of insulation deteriorisation mode and impacts on the reliability of high voltage equipment. Therefore, PD measurement is used for diagnostic technique of high voltage equipment. Diagnostic output of high voltage equipment contain information about PD type, PD cause, PD location and PD severity. after identification, a proper preventive maintenance pattern can be performed. Therefore PD pattern recognition system is very important on PD diagnostic system to recognize the PD pattern and determine the level of hazard that occurs in specimen object or high voltage equipment‥ In this paper, PD pattern recognition system is designed with fractal geometry approach and support vector machine (SVM) algorithm. The coding and programming of graphical user interface of the application is done. Each PD type and hazard level on various insulating materials (solid, liquid and gas) have the dimensions of the fractal and the lacunarity. The type of PD (void, corona) and its danger level (bad, fair and good) can be identified with the support vector machine (SVM)
A review of low-cycle fatigue of Alloy 617 for use in VHTR components: Experimental outlook
Authors: Dewa Rando Tungga , Park Jeong-Hun , Kim Seon-Jin , Kim Woo-Gon , Kim Eung-Seon , Haryadi Gunawan D. , Ekaputra I. M. W.
Published: March 2018

The effect of strain range and temperature on the low-cycle fatigue behaviour and microstructure change during cyclic deformation of Alloy 617 for use in very high temperature gas-cooled reactor components were studied at elevated temperature starting from ambient condition. Increasing the strain range and the temperature was noticed to reduce the fatigue resistance of nickel-based Alloy 617 due to facilitating the transformation behavior of the carbides in the grain interior, precipitates along the grain boundary, and oxidation behavior inducing surface connected precipitates cracking. Initial hardening behavior was observed at room temperature condition during cyclic due to the pile-up dislocation of micro-precipitates. The grain size was also taking a role due to the formation of an obstacle in the matrix. In the high temperature regime, the alloy 617 was found to soften for its entire life due to the fast recovery deformation, proved by its higher plasticity compared with lower temperature. The deformation behavior also showing high environmentally assisted damage. Oxidation behavior was found to become the primary crack initiation, resulting in early intergranular surface cracking.
Impact phenomena assessment: Part II – Buffer container as a measure to reduce cargo leakage in collision
Authors: Rio Prabowo Aditya , Jun Baek Seung , Geon Lee Seung , Myung Bae Dong , Min Sohn Jung , Bahatmaka Aldias , Samuel Samuel
Published: March 2018

The safety of ship under collision has been developed in terms of navigational and structural aspects. These efforts are aimed to provide more safety from the internal part of a ship. However, in a collision, the external dynamics also needs to be considered, for instance velocity and location. In this study, these parameters are applied and observed regarding on a series of ship-container collision scenario. A freight container is used in the first stage and behaviours such as internal energy and effective stress are summarized. An alternative design so called buffer container is presented to offer better protection to a liquid cargo. The second stage is started by applying similar collision scenario as the first stage to the buffer container and comparing structural behaviour of this analysis. It is obtained that leakage possibility can be reduced on the buffer design as the strength has become approximately twice better than the freight container.
Analysis of Effect of Bulbous Bow Shape to Ship Resistance in Catamaran Boat
Authors: Chrismianto Deddy , Kiryanto  , Arswendo Adietya Berlian
Published: March 2018

Ship resistance is one of the main factors affecting the design of a ship. Catamaran boat is a ship with small wet surface area that able to reduce drag and improve ship power. Generally, a bulbous bow is implemented to reduce wave resistance because the bulbous shape is believed to attenuate the bow wave system. Additionally, the bulbous bow also tends to reduce viscous resistance. When the flow around the body is smooth, the total ship resistance can be reduced significantly if the optimum bulbous bow is obtained. In this study, the main purpose is to get the bulbous bow shape in catamaran boat which produces the smallest ship resistance by using computational fluid dynamic (CFD). Generating the variation of the bulbous bow shapes apply the one-to-one correspondence of the cross section parameter (ABT) and lateral parameter (ABL). The result of investigation shows that application of bulbous bow on catamaran boat can reduce about 11-13% of total resistance of ship.
Impact phenomena assessment: Part I – Structural performance of a tanker subjected to ship grounding at the Arctic
Authors: Prabowo Aditya Rio , Byeon Jung Hoon , Cho Hyun Jin , Sohn Jung Min , Bae Dong Myung , Cho Joung Hyung
Published: March 2018

The remarkable influence of the global warming to Arctic environment opens a possibility to conduct a voyage from Asia to Europe through the Northern Sea Route (NSR). This option is considered as a decent solution to reduce fuel consumption and increase time efficiency in delivering cargo to the designated destination. However, this alternative comes with a challenge to keep safety of ship structures against an impact with obstacles which are possibly encountered at the Arctic. Solid ice can be considered as a serious threat to the double bottom of ship structures in impact phenomena, especially ship grounding. In this work, a series of grounding calculations are conducted to produce estimation of structural crashworthiness during interaction between double bottom and conical type ice. Material characteristics based on tensile testing of polar class material are applied to calculation and compared with non-polar steel.