bluuebunny/crossref_metadata_2025 huggingface dataset:
The VLA-COSMOS 3 GHz Large Project: Star formation properties and radio luminosity functions of AGN with moderate-to-high radiative luminosities out to z∼ 6
Authors: Ceraj L. , Smolčić V. , Delvecchio I. , Novak M. , Zamorani G. , Delhaize J. , Schinnerer E. , Vardoulaki E. , Herrera Ruiz N.
Published: November 2018

We have studied a sample of 1604 moderate-to-high radiative luminosity active galactic nuclei (HLAGN) selected at 3 GHz within the VLA-COSMOS 3 GHz Large Project. These were classified by combining multiple AGN diagnostics: X-ray data, mid-infrared data and broadband spectral energy distribution fitting. We decomposed the total radio 1.4 GHz luminosity (L1.4 GHz, TOT) into the emission originating from star formation and AGN activity by measuring the excess in L1.4 GHz, TOT relative to the infrared-radio correlation of star-forming galaxies. To quantify the excess, for each source we calculated the AGN fraction (fAGN) defined as the fractional contribution of AGN activity to L1.4 GHz, TOT. The majority of the HLAGN, (68.0 ± 1.5)%, are dominated by star-forming processes (fAGN ≤ 0.5), while (32.0 ± 1.5)% are dominated by AGN-related radio emission (0.5 <  fAGN ≤ 1). We used the AGN-related 1.4 GHz emission to derive the 1.4 GHz AGN luminosity functions of HLAGN. By assuming pure density and pure luminosity evolution models we constrained their cosmic evolution out to z ∼ 6, finding Φ*(z)∝(1 + z)(2.64 ± 0.10)+(−0.61 ± 0.04)z and L*(z)∝(1 + z)(3.97 ± 0.15)+(−0.92 ± 0.06)z. These evolutionary laws show that the number and luminosity density of HLAGN increased from higher redshifts (z ∼ 6) up to a maximum in the redshift range 1 <  z <  2.5, followed by a decline toward local values. By scaling the 1.4 GHz AGN luminosity to kinetic luminosity using the standard conversion, we estimate the kinetic luminosity density as a function of redshift. We compare our result to the semi-analytic models of radio mode feedback, and find that this feedback could have played an important role in the context of AGN-host co-evolution in HLAGN which shows evidence of AGN-related radio emission (fAGN >  0).
Stiffness Modulus of Asphaltic Concrete Incorporating Coir Fibre and Subjected to Aging
Authors: Mohammed Abdullahi Ali , Putra Jaya Ramadhansyah , Marie Delbrel Étienne Joseph , Wee Kang Choong , Ti Kok Sien , Yaacob Haryati , Abdul Hassan Norhidayah , Abdul Hamid Nor Hayati , Ramli Noram Irwan
Published: November 2018

The aim of this paper is to investigate the performance response of a set of coir fibre modified asphalt samples subjected different ageing conditions and containing three different fibre contents. The laboratory experimental programs are indirect tensile test at 25°C and repeated load axial test at 40°C. The results showed that the fibres improved the mixture’s performance. The main findings obtained at 25°C for short and long-term ageing reveal that low fibre content at around 0.3% per aggregate weight display a stiffness modulus up to 14% higher than that of unmodified mixtures, hence showing that fibres may improve the bearing capacity and rut-resistance of asphalt mixtures. Conversely, as the amount of fibre increases to 0.5% and 0.7%, the stiffness decreases to the point of becoming unacceptably low, almost 80% lower than unmodified mixes stiffness. However the data also reveal that high fibre contents at 0.5% and above completely neutralize the impact of ageing on the mixture, indicating that fibre-modified mixtures would yield longer lives.
Reinforced Concrete Buildings with Plane Frame, Shear Wall with and without Openings
Authors: Nizamani Zafarullah , Luk Wong Che , Haider Syed Muhammad Bilal
Published: November 2018

Malaysia is situated at Sunda plate which has geographic advantage in seismic zone. However, an earthquake occurred in Sabah, east of Malaysia without a warning in 2015. This scenario raised the question regarding the structural performance of high-rise buildings in Malaysia in response to seismic activity. This study is to analyze the effects of the shear wall on seven RC buildings by using pushover analysis. This pushover analysis is a simple approach where a building is subjected to increasing horizontal lateral loads until the building fails. SCIA Engineer software is used to model three different designs of seven storeys buildings are model in accordance with the Eurocode 8. The pushover analyses are carried out on three models, pushover curves (base shear vs. roof displacement) are plotted, and they are compared to explore both elastic and inelastic properties of the building response to the seismic action. The frame model without shear wall can resist less base shear. The plane frame model also approaches maximum allowable displacement of 60 mm earlier as compared to the other two models. Therefore, the high-rise buildings with shear wall design are highly recommended for the lifelong seismic resistance of reinforced concrete buildings.
A Review of Minimizing Delay in Construction Industries
Authors: Khoiry Muhamad Azry , Kalaisilven Suhaniya , Abdullah Azlina
Published: November 2018

Construction is an important industry to determine the development of a country. However, this industry faced delay issues caused by various factors that affect proper construction project. Hence, minimizing delay in construction should be focused on overcoming the delay issue. Thus, the objective of this study is to critically review the main criteria of minimizing delay based on the most significant items that suggested in the previous journals. This paper reviewed 47 journals that studied the issues of delays in construction projects. Through this study, the authors have classified four main criteria for minimizing delays, which are; management, interpersonal, technical and technology. Management ensures the proper manage of time, financial and control system in construction to minimize delay. While, interpersonal promote a good relationship between construction parties, hire of competent and skilled labour and responsibility of the owner to avoiding delay. Besides, technical ensure the quality of project and technology could improve the productivity of construction based on fourth industrial revolution development in the construction field. Thus, this study contributes to construction parties able to focus on elements to overcome the delay issue in they faced and applied the ideas based on the element to minimize delay in the construction project.
Factors Influencing Engineers’ Attitude towards Environmental Sustainability
Authors: Fauzi Siti Nur Fazillah Mohd , Yusof Nor’Aini , Awang Hanizam , Nah Mohd Nurfadzli Mat
Published: November 2018

Engineers have a vital role in addressing environmental degradation in construction projects. Therefore, engineers’ positive attitude towards the environment is important to ensure that construction projects are carried out responsibly. The objective of this paper is to investigate the factors that influence engineers’ attitude towards green practice. Six factors; Knowledge, Self-initiative, Firm Support, Government Support, Board of Engineers Support and Client Attributes were assumed to influence the engineers’ attitude towards green practice. A self-administered survey with 37 items was distributed to engineering firms in Peninsular Malaysia and 128 usable responses were received. The results show a moderate relationship with 32 percent of the variances in the relationship between the six factors and engineers’ attitude. The results reveal that self-initiative and government support have a significant and positive impact on the engineers’ attitude towards green practice with the higher effect coming from the support from the government (f2 = 0.210) as compared to self-initiative (f2 = 0.058). In contrast, the results provide insufficient evidence about the relationship between Knowledge, Firm Support, Board of engineers Support and Client Attributes and engineers’ attitude towards green practice. The results serve as a guide to the policy makers and engineers to ensure responsible attitude can be adopted towards the environment.
Effect of H2O2Oxidation/Alkaline Hydrolysis on Waste Activated Sludge Disintegration and Dewaterability
Authors: Heng Gan Chin , Isa Mohamed Hasnain , Lim Ming Han
Published: November 2018

In the present study, the effect of hydrogen peroxide oxidation/alkaline hydrolysis was investigated on waste activated sludge (WAS), to enhance its disintegration and dewaterability. The effects of three operating parameters viz., pH, H2O2dose and reaction time, on the degree of WAS disintegration and dewaterability were assessed using response surface methodology. The optimum operating variables to achieve VSS removal 20%, CST reduction 20%, sCOD 6100 mg/L and EPS 455 mg/L were: pH 10.5, 1300 g H2O2/kg TS and 40 min reaction time. Results showed that WAS can be efficiently disintegrated and dewatered by H2O2 oxidation/alkaline hydrolysis for subsequent biological digestion.
Opportunity of Biogas Production from Solid Organic Wastes through Anaerobic Digestion
Authors: Pramanik Sagor Kumar , Suja Fatihah Binti , Pramanik Biplob Kumar , Zain Shahrom Bindi Md
Published: November 2018

Solid organic wastes create potential risks to environmental pollution and human health due to the uncontrolled discharge of huge quantities of hazardous wastes from numerous sources. Now-a-days, anaerobic digestion (AD) is considered as a verified and effective alternative compared to other techniques for treating solid organic waste. The paper reviewed the biological process and parameters involved in the AD along with the factors could enhance the AD process. Hydrolysis is considered as a rate-limiting phase in the complex AD process. The performance and stability of AD process is highly influenced by various operating parameters like temperature, pH, carbon and nitrogen ratio, retention time, and organic loading rate. Different pre-treatment (e.g. mechanical, chemical and biological) could enhance the AD process and the biogas yield. Co-digestion can also be used to provide suitable nutrient balance inside the digester. Challenges of the anaerobic digestion for biogas production are also discussed.
Removal Process of Nutrients and Heavy Metals in Tropical Biofilters
Authors: Hermawan Andreas Aditya , Jung Da Yoon , Talei Amin
Published: November 2018

Biofilters are relatively new pollution control technology used to treat urban stormwater runoffs. Biofilters generally consist of vegetated top soil layer for nutrient uptake and sand-based filter media for heavy metals filtration. While the complex process of pollutant removal is studied for a temperate environment, only a few studies have been conducted under tropical climate conditions. This study aims to study the removal process of total nitrogen, total phosphorus and 6 heavy metals including copper, iron, manganese, nickel, lead, and zinc in a tropical biofiltration system. In this study, using the curve fitting analysis, the parabolic function was found to be the most fitted function to explain the relationship between pollutant concentration in the effluent and the infiltration rate of the system when the first flush phenomenon is simulated. Results demonstrated that the natural variation of infiltration rate during the saturation process of soil influences the performance of the system in removing some pollutants such as phosphorus, iron, and zinc.
Estimation of Ground Structure at USM using Microtremor Observation Technique
Authors: Tan Kang Chin , Cheah Yi Ben , Lau Tze Liang
Published: November 2018

Determination of ground structure is important for seismic hazard analysis and earthquake design of structures. Different types of ground structure at site, depending on its profile of shear-wave velocity, will amplify seismic wave at different extents. Therefore, structures should be designed accordingly to withstand the expected surface ground motion considering seismic site amplification. Microtremor observations were conducted in this study due to its simplicity, less field effort and economy. Field measurement was carried out at two sites at Universiti Sains Malaysia Engineering Campus where the actual soil profiles were known from the existing borelog data. Two sizes of circular array formed by three three-component velocity sensors along the circumference of circle and a three-component velocity sensor at the center for each array were performed. The recorded data were analysed using Spatial Autocorrelation (SPAC) method. Shear wave velocity profile for the site was then estimated through inversion of phase velocity. To produce convincing estimation of ground structure, the horizontal to vertical (H/V) spectra at the center of the circular array was compared with the computed ellipticity of the fundamental mode of Rayleigh wave. The obtained results were also compared with the borelog data. The accuracy for the estimation of ground structure based on various microtremor array sizes and analysis techniques was assessed.
Exploratory Research of New Curve Number System
Authors: Tan Wen Jia , Khor Jen Feng , Ling Lloyd , Huang Yuk Feng
Published: November 2018

In the past, theCNwas determined through SCS handbook. In order to determine runoff prediction using SCS-CN model, selection ofCNis important. However, the conventionalCNmethodology with inappropriateCNselection often produces inconsistent runoff estimation. Thus, the new direct curve number derivation technique based on rainfall-runoff datasets with supervised numerical optimization technique under the guide of inferential statistics was developed to improve the accuracy of surface runoff prediction. Furthermore, the two decimal pointCNsystem was proposed in this study. The optimumCNof Melana site is 90.45 at alpha 0.01 with BCa 99 % confidence interval range from 90.45 to 95.12. The regional specific calibrated SCS-CN model with two decimal pointCNderivation technique is out-performed the runoff prediction of conventional SCS-CN model and the asymptotic curve number fitting method.
Linear discontinuous deformations in the light of investigations performed with ERT method
Authors: Strzałkowski Piotr , Ścigała Roman , Szafulera Katarzyna , Kruczkowski Marek
Published: November 2018

The article presents an example of using the electrical resistivity tomography method to assess the condition of shallow rock mass layers in the area of linear discontinuous deformations created in the past due to underground mining activity. The research concerned the mining area of one of the Upper Silesian Coal Basin mines, where intensive mining operations have been conducted for several decades. In the considered area, linear discontinuous deformations were created in the form of ground steps. Their location is related to characteristic layout of deposit accessing roadways and extraction fronts in several coal seams. The article analyzes the geological structure of the deposit and the state of deformation of the rock mass caused by mining operations. In order to evaluate the hitherto impacts, appropriate calculations of the extraction influence were performed, assuming different views on the summation of horizontal strain in long time intervals. The calculations were carried out using the theory of W.Budryk - S. Knothe. Theoretical considerations were supplemented with geophysical surveys performed with using electrical resistivity tomography. Obtained results of the near-surface layers ERT imaging in the form of resistivity profiles confirm the existence of rock loosening zones in the areas of discontinuous deformations occurrence.
ERT method in the study of chemical pollution of the hydrogeological environment - numerical analysis of 2D and 3D models
Authors: Bania Grzegorz
Published: November 2018

Electrical resistivity tomography (ERT) method is often used to solve problems related to chemical pollution of the hydrogeological environment. The source of such contamination can be, e.g. industrial heaps, tailings ponds and municipal landfills. The contaminants spreading often takes the form of a (3D) pollution tongue. In this case, the standard interpretation of 2D ERT surveys may be difficult. Numerical modeling was carried out in order to show the specificity of pollutants propagation. Both 2D and 3D models were analysed. Those refer to the real geological situation - vicinity of Nowa Huta (Krakow, Poland) - where heaps and tailings ponds of the metallurgical plant are present. An appropriate geoelectrical model referring to the above situation was prepared. It was assumed that highly mineralized waters in the form of a contamination tongue are spreading within the aquifer. Resulting interpreted resistivity distributions for 2D and 3D variant of ERT method were analysed. It has been shown that the method is promising in terms of the ability to detect and assess the nature of the transitional zone between clean and contaminated waters. Additionally, it has been shown that 3D modeling can be a useful, complementary element in interpreting the results of DC-resistivity methods.
Stability analysis of the Kosciuszko Mound using terrestrial laser scanner and numerical modelling
Authors: Pilecka Elżbieta , Tomaszkiewicz Karolina
Published: November 2018

Landslides which form in anthropogenic soils are complicated from a geological engineering and geotechnical point of view. Each case requires a detailed investigation and the selection of effective reinforcements is a difficult project issue. The study presents the problem of the stability analysis of landslides occurring in the anthropogenic soils of the Kosciuszko Mound in Cracow. The previously performed protections are discussed to highlight their ineffectiveness and the current technical condition of the mound is also presented. By overlapping the results of displacement measurements made with a terrestrial laser scanner, a differential model of the terrain was created which made it possible to determine the size and direction of the deformation of the slopes of the mound and the tendencies for the development of landslide movements in this area. A cross-section, selected on the basis of the model, was numerically analysed using the finite element method (FEM) in the Midas GTS NX program. As a result of the analysis, the values of the displacements and strains occurring in the Mound were calculated. On the basis of the value of the safety factor obtained, it was also possible to assess the risk of landslide movements.
Remote sensing of Carpathian flysch landslides with the use of terrestrial laser scanner
Authors: Kogut Janusz P. , Tymoshenko Ievgen
Published: November 2018

Terrestrial laser scanning helps us to detect unstable subsurface behaviour, assessing the slope stability and potential landslide failure modes. If the slopes are regularly observed, the risk of slope movement and subsequent consequences may be considerably reduced. This allows for optimum land use conditions that are economically justified. Landslides in the Carpathian flysch have a peculiar susceptibility to activation due to the region’s geological structure. This work addresses the problem of monitoring and analysing the effects of landslides associated with the operation of routes (roads and railway lines) running through the slopes of the Carpathian flysch. The terrestrial laser scanner enables site remote sensing in a simple and automated manner. Regular measurements with multiple scanner positions may be used for long term slope monitoring. A detailed geological structural model allows for risk assessment with regards to failure modes, and it allows for a slope stability assessment. The model, along with the substrate parameters, introduced into the Finite Element Analysis package enables an analysis of the effects of landslide susceptibility and the displacements of the terrain surface in time, as well as due to different loading cases.
Long-term study of the impact of temperature changes, material aging and service load on the strains of a reinforced concrete structure
Authors: Kanciruk Adam
Published: November 2018

The article discusses five year long measurements of strains of a concrete floor of a hangar. That hangar, originally meant for servicing light military aircraft, was rebuilt with a view to making it fit for servicing larger and heavier passenger planes. As part of that redevelopment, a new floor - reinforced concrete slab, capable of withstanding the weight of the planes - was constructed. In the areas of the floor where the greatest loads occur, ie. in the areas of the concrete slab on which the wheels of the three undercarriage legs rest, three strain rosettes were installed so that the slab strains could be measured. The rosettes were connected to two meters - dataloggers. The latter were programmed in such a way as to register the measured strains and additionally temperatures many times during every 24 hours. The monitoring process, conducted in such an automatic way, demonstrated the occurrence of strains resulting from service load, aging of the reinforced concrete, as well as changes in its temperature.
Interpretation of rock mass thermal conductivity at the design stage of heat pump installation and its impact on system efficiency (COP)
Authors: Kaczmarczyk Michał , Kaczmarczyk Magda , Thürmer Konrad , Klich Magdalena
Published: November 2018

The recognition of geological and thermal conditions of the rock mass in the case of designing a vertical borehole heat exchanger as the ground source for heat pump installations is a key issue affecting the efficiency of the heating/cooling system operation. This is especially important for large-sized buildings with a high demand for thermal power, which affects into the size of the ground source installation. The aim of the article is to indicate the difference in the obtained results concerning thermal calculations at the design stage of the brine/water heat pump installation with the vertical heat exchanger, in relation to the theoretical values of the rock mass thermal conductivity and the real (measured) values obtained during the thermal response test (TRT). For this purpose, calculations of thermal efficiency from one meter of the current rock mass were made, with particular emphasis on the change in the value of the thermal conductivity coefficient in the tested drilling profiles. Correspondingly, heat pump coefficients of performance (COP) were calculated, which allowed to analyze the influence of the over/undersizing phenomenon of the ground source on the technical parameters of the heat pump's operation and the economic effect of the investment.
Experimental study of water cooling effect on heat transfer to increase output power of 180 watt peak photovoltaic module
Authors: Safitra Arrad Ghani , Sholihah Fifi Hesty , Tridianto Erik , Baihaqi Ikhsan , Indah T. Ni Nyoman Ayu
Published: November 2018

Photovoltaic (PV) modules require solar radiation to generate electricity. This study aims to determine the effect of water cooling PV modules on heat transfer, output power, and electrical efficiency of PV modules. The experiments carried out in this study were to vary the heights of flooded water (with and without cooling water replacement control) and cooling water flow. Variations in the height of flooded water are 0,5 cm, 1 cm, 2 cm, and 4 cm. While the flow rate variations are 2 L/min, 4 L/min, and 8 L/min. The flooded water replacement control will be active when the PV surface temperature reached 45°C. When the temperature dropped to 35°C, the cooler is disabled to let more photon to reach PV surface. The results showed that the lowest heat transfer occurred in the variation of 4 cm flooded water height without water replacement control, i.e. 28.53 Watt, with an average PV surface temperature of 32.92°C. The highest average electric efficiency occurred in the variation of 0,5 cm flooded water height with water replacement control, i.e. 13.12%. The use of cooling water replacement control is better due to being able to skip more photons reach PV surface with low PV temperature.
Development of simple solar charge controller using 8-bit microcontroller attiny85
Authors: Wing Wira A.R. , Rezky Ananta , Bastian Andrew , Devara Kresna , Udhiarto Arief , Abuzairi Tomy
Published: November 2018

This paper present simple and inexpensive solar charge controller (SCC) using 8-bit microcontroller ATtiny85. The SCC using a pulse width modulation (PWM) signal to transistor and MOSFET to control current that generated by the microcontroller. The battery voltage state also monitored using a series resistor paralleled to the battery and the voltage drop connected to the microcontroller. The design of SCC consists of 3 major part i.e. microcontroller, current driver, voltage sensing. The purpose of measurement is to know the characteristics of 2 charging modes, mode 1 (one) and mode 2 (two), that occur in the system created. The measured data is the battery voltage as independent variable, and the solar panel’s voltage, the current that flow towards battery and the power provided for charging. Measurements are conducted from the battery voltage state of 7.84 V to 8.4 V. The results show that the solar charge controller using 8-bit microcontroller ATtiny85 was successfully managed to provide current and voltage according to expected design with 400 mA, 8.9 V for the first charging case and 150 mA, 12 V for the second charging case.
Retuning PI controller to improve the control performance in CO2 removal process, subang field
Authors: Wahid Abdul , Mahdi
Published: November 2018

A proportional - integral controller retuning is performed on CO2 removal process, Subang field. Retuning is carried out to improve the control performance on the process. The method used is to evaluate the controllers that are retuned the controller parameters, identify the system using the first-order plus dead time model (FOPDT), tune the controller parameters using the Ziegler-Nichols, Wahid-Rudi-Victor (WRV), Cohen-Coon, autotuning, and fine tuning, and the last, the control performance tests using set point (SP) tracking and disturbance rejection with performance indicator is integral of square error (ISE). The result is that there are three controllers that are retuning the control parameters, i.e., the feed gas pressure control (PIC - 1101), the makeup water flow control (FIC - 1102), and the amine circulation flow control (FIC - 1103). Only a fine tuning method produces the best control performance compared to previous settings in the field, with performance improvements of 77,42% (PIC - 1101), 90,59% (FIC - 1102), and 13,06% (FIC - 1103) for -5% set point (SP) tracking. While for disturbance rejection, fine tuning gives performance improvements of 86,04% (PIC - 1101), 90,8% (FIC - 1102), and 24,8% (FIC - 1103). Thus, retuning PI controllers work well.
Experimental investigations of ice slurry flow based on monoethylene glycol at high ice fractions
Authors: Yanuar  , Utomo Gilang G , Rayhan Fajri A , Akbar M , Pamitran Agus S
Published: November 2018

Ice slurry has so many advantages as phase-change slurries due to the high latent heat of its particles. Ice slurry is one of a competitive alternative to conventional secondary refrigeration systems that have been successfully employed in many applications. In this research, ice slurry flow with monoethylene glycol (MEG) at high ice fractions was investigated. The experiment was carried out by measuring shear stress and flow rate as variable to calculate power law index. The experiment was performed in 14 mm, 21 mm, and 24 mm circular tubes, respectively. The Initial concentration of 5 wt%, 7 wt%, and 10 wt% of MEG was investigated. Ice fraction was maintained above 30% in a storage tank. Experimental results of the Darcy friction factor were compared to Poiseuille and Blasius model. The ice slurry flows exhibited a shear-thickening flow (n>1) for all initial concentration in the range 1.07 - 1.58. The Greater initial concentration of MEG tends to give smaller friction compared with another ice slurry flow with smaller initial concentration.
Performance of novel dielectric barrier discharge reactor for biodiesel production from palm oil and ethanol
Authors: Ramadhani Sari Dafinah , Fakhri Saphira Nurina , Bismo Setijo
Published: November 2018

The disadvantages of conventional biodiesel synthesis trigger the birth of new biodiesel synthesis methods using the DBD plasma reactor. The conventional methods with homogeneous and heterogeneous catalysts have significant constraints that the formation of glycerol compounds in large enough quantities that require considerable energy. The aim of present experiment is to design DBD non-thermal plasma reactor coaxial pipe type and to do its performance test in converting biodiesel The feed stock used are palm oil, ethanol, and argon gas as plasma carrier. Such a chemical reactor, this plasma reactor is also influenced by reaction kinetics and hydrodynamic factors. From this research, it can be seen that the optimum feed and gas flowrate being operated is 1.64 and 41.67 mL/s. The plasma reactor is used in the form of a quartz glass tube surrounded by a SS-314 spiral coil as an outer electrode. The applied operating conditions are 1 : 1 molar ratio of methanol/oil, ambient temperature of 28 - 30 °C, and pressure 1 bar. From this performance test, it is found that this plasma reactor can be used to synthesize biodiesel from palm oil and methanol without catalyst, no formation of soap, and minimal byproducts.
Evaluation of Waste Energy Conversion Technology using Analitycal Hierarchy Process in Bantargebang Landfill, Indonesia
Authors: Siregar Sri R H , Saragih Budiman R , Surjosatyo Adi
Published: November 2018

In Indonesia, the waste to energy conversion technology has been installed and operate in some landfill, such as Bantargebang landfill where applied landfill gas recovery methods. Evaluate the running process is important to optimize the installed facilities and the other potential technology. This paper aims to evaluate the running process technology in Bantargebang landfill compare with the other waste to energy technology so it can be used as a reference for upgrading technology. Evaluation using Multi Criteria Decision Making techninque with observe method Analitycal Hierarcy Process adopt energy (energy content and net electrical output), environment (MSW reduction and GHG emission), and economic (initial cost and operation maintenance cost) as criterions. The results shows that the anaerobic digestion as alternative technology is the best technology with total point 2.71, followed by inceneration pelletization at second rank with total point 2.70, and running process landfill gas recovery at third rank with total point 2.56.
Effect of hydrotreating in biodiesel on the growth of deposits in the combustion chamber as a solution for the deposits reduction in the usage of biodiesel
Authors: Mulyono Ary Budi , Sugiarto Bambang , Suryantoro Muchammad Taufiq , Setiapraja Hari , Yubaidah Siti , Attharik Mochammad Ilham , Ariestiawan Muhamad Raihan , Cohen Andro
Published: November 2018

The usage of biodiesel has been encouraged by government based on the issuance of The Regulation of Minister of Energy and Mineral Resources No. 12/2015 on the supply, utilization, and administration of biofuels as other alternative fuels. This regulation sets mandatory biodiesel mixture by 30 percent for national energy consumption by 2025. But the usage of biodiesel with a larger percentage in diesel engines still leaves some problems with the decline of biodiesel fuel quality and the formation of deposits in combustion chamber and injectors. The purpose of this study is to compare biodiesel fuel (B20) with Hydrotreated Biodiesel (HBD) in an experiment by using fuel droplet method on a plate to observe the characteristics and mechanism of deposit formation. Plates are heated in few temperature variations in a sealed test rig so that the conditions are similar to the engine real conditions. Deposit growth of Hydrotreated Biodiesel as known as Hydrotreated Vegetable Oil (HVO) less better than Fatty Acid Methyl Ester (FAME). It may occurred because the lubricity of HVO is very low due to the absence of sulfur and oxygen compounds in the fuel, that causes oxidation that can lead to deposits in the combustion chamber.
Biodiesel deposit characterization on hot chamber test rig with biodiesel fuels (B20) and bioaditif essential oil (atsiri)
Authors: Suryantoro Muchammad Taufiq , Sugiarto Bambang , Setiapraja Hari , Yubaidah Siti , Mulyono Ary Budi , Attharik Mochammad Ilham , Ariestiawan Muhamad Raihan , Cohen Andro
Published: November 2018

In this study, the deposit formation of B20-NA biodiesel with the addition of bioadditive Essential Oil with different variations, B20 + Essential Oil 1:2000, B20 + Essential Oil 1:3000, B20 + Essential Oil 1: 4000 and B20 + Essential Oil 1:5000 method of hot plate drops to know the characteristics and mechanisms of deposit formation on each variation of fuel. The research is carried out by the deposition process and evaporation of Diesel fuels carried out repeatedly on a hot plate. The plate is heated with temperature variations inside the enclosed space so that the conditions are close to the real conditions of the engine. This test uses a hot chamber test rig. The use of bioadditive essential oils (atsiri) which have turpentine contents bind water content and residues in biodiesel fuel is expected to accelerate the process of excessive deposit release in the combustion chamber. This study aims to find the optimum fuel and temperature variations so that the deposit release process can be accelerated.
Feasibility Study for Production of Zeolite A based on Kaolin
Authors: Simanjuntak Agustina A.Y. , Kusrini E.
Published: November 2018

In industry, kaolin is widely employed as an additive to paper, rubber and ceramics, among other uses, and can be synthesized into zeolite. Zeolites have been hydrothermally synthesized using alumina and silica based on deposits (kaolin) sampled from region in Bangka- Belitung. The synthesis of Zeolite A based on kaolin through several process stages such as drying, grinding and sieving prior to the hydrothermal process. It is then calcined into metakaolin, followed by the addition of NaOH solution, heating, filtration and washing to obtain the synthesis. This study examines how assessment models can be built and used for financial, technical, and marketing feasibility analysis of synthesized Zeolite A from kaolin. A new optimization method used to estimate financing requirements of investment products is presented, as well as a new method to predict the optimal year to sell the product. The conclusion is that Net Present Value with a positive value, Pay Back Period, Internal Rate of Return 30.78% higher than the interest rate set at 12%, and marketing aspects show that the process is feasible.
Effect of NiMo/Zeolite Catalyst Preparation Method for Bio Jet Fuel Synthesis
Authors: Habibie Thareq Kemal , Susanto Bambang Heru , Carli Michaelle Flavin
Published: November 2018

Bio jet fuel is an alternative fuel derived from vegetable oil substitutes for conventional aviation fuel. Bio jet fuel can be synthesize through hydrodeoxygenation and catalytic cracking process pathways that influence by the catalyst. The success rates of bio jet synthesis with catalysts influence by the characteristic and activity of the catalysts. One factor that influence the catalyst characteristic and activity is the preparation method. This study focuses on the preparation method of a catalyst by comparing the conventional method of impregnation and the latest microwave polyol method. The impregnation method utilizes stirring up to 24 hours while microwave polyol utilizes a microwave for rapid heating which serves to expand the active core, but the catalyst is not yet known its character and its activity in bio jet fuel synthesis process. In this study, NiMo/Zeolite was synthesized by impregnation method had 232.18 m2/gram surface area and had average crystal size of 49.35 nm. Further, the catalyst was used to synthesized bio jet fuel through a catalytic cracking process, with green diesel from the hydrodeoxygenation process of oleic acid conversion as feed. The result, obtained high enough of conversion by 84.30%, but low yield and selectivity of bio-jet fuel range by 34.77% and 36.43% respectively.
The combined process of pyrolysis and catalytic conversion from rice straw toward light olefin hydrocarbon with supported metal catalyst
Authors: Setiadi  , Sentosa Jayusandi Mulya , Karubaba Joshua Jesse
Published: November 2018

Light olefins are one of the most common petrochemical raw materials produced using non-renewable natural resources. Nowadays, lignocellulosic biomass is a promising source of feedstock ingredients for the production of olefins by pyrolysis. This study, the process is developed by a combination of pyrolysis and catalytic cracking processes with operating temperature around 500°C and N2 flow rate around 150 ml/min. The supported metal catalyst namely La/Al2O3 and Zn/Al2O3 made with the impregnation method are used as catalysts. The catalytic pyrolysis process was carried out in a fixed bed turbular reactor with electric furnace as the heat source. To comprehend the catalytic cracking with catalyst, the experiment was also performed in condition without catalyst so that it could be compared to pyrolysis process itself. The The output of pyrolysis is condensed by using cold absorption trap with aceton. FT-IR (Fourier Transform - Infrared) and GC-TCD (Gas Chromatography-Thermal Conductivity Detector) serve as analytical instrument in order to identify the presence and the quantity of light olefins group in bio-oil and bio-gas. In this method, there are several variations to be determine, there are type of catalyst and catalyst composition (1%, 5%, and 10%).
Modelling and simulation of a slurry bubble column reactor for green fuel production via hydrocracking of vegetable oil
Authors: Muharam Yuswan , Adevia Rizka Thalita
Published: November 2018

A slurry bubble column reactor to produce green fuel through hydrocracking of vegetable oil with Ni-W/SiO2-Al2O3 catalyst was simulated in this research with the objectives being to obtain a mathematical model of the reactor and an optimum operation condition. The steady state two-dimensional axisymmetric model of the slurry bubble column reactor with the diameter of 2.68 m and height of 7.14 m was modelled by considering mass and heat transfers. The very small liquid superficial velocity reflects that the liquid phase is in batch-like operation. The gas of 0.01 m/s in superficial velocity flows upward to suspend and agitate the spherical catalyst particles of 100 μm in diameter inside the reactor. The reactor operated at 80 bar and 420°C. Triglyceride of 5% w/w in dodecane and hydrogen of 105.5 mol hydrogen/triglyceride enter the reactor from the bottom. The research also considered pressure drop and loading catalyst distribution inside the reactor. Simulation results show that the triglyceride conversion is 99.26%, the product yield is 40.68% w/w, and the product purity is 45.55% w/w.
The Effect of Gasoline-Bioethanol Blends to The Value of Fuel’s Octane Number
Authors: Wibowo Cahyo Setyo , Sugiarto Bambang , Zikra Ardi , Budi Alva , Mulya Try , Maymuchar
Published: November 2018

A fuel gasoline engine classified based is octane number, test for octane number using CFR engine with RON (Research Octane Number) ASTM D 2699 and MON (Motor Octane Number) ASTM D 2700. Bioethanol can booster octane number if blended to gasoline. A fuel to a higher octane can be run at a higher compression ratio without causing detonation or knocking engine. Compression is directly related to thermodynamic efficiency but to blended bioethanol can decrease the heating value of the fuel. The design engine on the market had compression ratio specified and needed octane number minimum specified. The experimental using CFR engine and using fuel gasoline in the market with blended bioethanol start from 5% -20% and analysis the relationship octane number after blended bioethanol with value compression ratio gasoline engine at the market. The objective of this research was the effect of blended bioethanol of varying gasoline forward octane number. The effect of blended bioethanol of gasoline between 5%-20% could increase to 11% of gasoline octane 88, 2% of gasoline octane 98.
Determining the Optimum Total Solid Yield of Hydrothermal Waste Processing Products Through Mechanical Drying
Authors: Kristanto Gabriel Andari , Prajna Crysnarendra A.
Published: November 2018

In the application of hydrothermal technology, it is necessary to optimize mechanical water drying to increase the calorific value of hydrothermal waste products. This study was conducted to find the total optimum solids, optimum drying time, and characteristics of hydrothermal waste processing products that occur after optimal mechanical drying. The mechanical drying design was carried out 4, 6, and 8 bars of pressure. At pressure bars 4, 6, and 8, the total optimum solid yields were 50.11%, 51.56%, and 54.56%, with 6.56, 6.82, and 5.11 minutes of drying time, respectively. Optimum mechanical drying yielded a calorific value of 5154 kcal/kg, which is the equivalent of sub-bituminous coal. An increase of the C/N (Carbon to Nitrogen) ratio to 32.185 resulted in hydrothermal waste processing products that did not comply with the Indonesia compost quality standard.
Evaluation of Waste Potential in TPST Bantargebang Through Modified Triangular Method
Authors: Saragih Budiman R , Siregar Sri R H , Surjosatyo Adi
Published: November 2018

The landfill gas technology has been implemented in some landfill in urban area of Indonesia. Bantargebang integrated waste treatment (TPST Bantargebang) is the first landfill completed with energy recovery facility, landfill gas technology. TPST Bantargebang power plant established in 2010 and supplied electricity to grid. The electrical energy supplied tend to decrease and only reaches 2.4 GWh in 2017. Energy potential is important to evaluated for knowing the performance of TPST Bantargebang power plant. By using Modified Triangular Method, obtained the results that the electricity energy potential equal to 4.5 GWh. The calculation also estimate the emission reduction potential about 4325.88 tCO2/year, and economic potential from sales of electricity about 3.7 billion rupiah.
Palmemptyfruitbunch gasificationsimulationin circulating fluidized bed gasifier
Authors: Heryadi Rudy , Uyun Aep Saepul , Yandri Erkata , Nur Syukri M , Abdullah Kamaruddin
Published: November 2018

Biomass from EFB is considered as potential renewable energy sources to be developed in Indonesia. EFB can be efficiently converted into valuable and useful gaseous products through gasification. Research about EFB gasification in various gasifier has been done, though little research about EFB simulation on CFB bed gasifier. The aim of this research is to simulate gasification of EFB on CFB gasifier by assuming that the gasification reaction isunder equilibrium condition. Method encompasses biomass feedstock, simulation basis manager, process description, simulation description, model validation, and sensitivity analysis. The model predicts H2 and CO fraction on syngas product in agreement with published real CFB gasification operation. The result shows that CFB gasifier performance is improving at high temperature above 800°C., and syngas conversion is higher under high temperature.The highest H2 yield achieved at 800°C.Impact of S/B has been investigated, and it is found that when value of S/B is increasing, the more H2 produced. The value of ER below 1 is desired since the focus is to get CO together with H2. The lower ER value the higher syngas yield obtained. The model will be used as a basis for further chemical production simulation from EFB gasification.
Analysis of the use of thermoelectric generator and heat pipe for waste heat utilization
Authors: Hakim Imansyah Ibnu , Putra Nandy , Usman Mohammad
Published: November 2018

Waste heat recovery is one way to reduce the use of fossil fuels, one of them is by using thermoelectric generator to convert waste heat into Thermoelectric Generator (TEGs) is a module that can convert heat into electrical power directly, using Seebeck effect and Peltier effect as its working principle, so it can increase efficiency of energy consumption by utilizing waste heat from an instrument that generate waste heat. The focus of this research is to find the output voltage of TEG by utilizing the temperature difference on the cold side and the heat side of the TEGs. The heat side of the module will be given heat from the heater as a simulation of the heat from hot water, and on the cold side heat pipes will be used to remove the heat on the cold side of TEGs. The result, output voltage that generated by using 4 module TEGs that arranged to Thermal Series - Series Circuit and using 2 heat pipes is 2.1-volt, and then it is possible to use for phone charger.
Synthesis of composite Li4Ti5O12 nanorods/Sn-AC as anode material for lithium-ion battery
Authors: Zulfia Anne , Betalia Aisha , Priyono Bambang , Subhan Achmad
Published: November 2018

LTO or Li4Ti5O12 (lithium titanate) is a compound that is used as an anode component in a lithium-ion battery. LTO anode is used because it has zero-strain properties and doesn't produce SEI (solid electrolyte interphase) which cause low battery performance. However, LTO also has a problem, which is its low capacity. To overcome this problem, the LTO needs to be combined with other materials that have high capacity, which, in this case, are active carbon (AC) and Sn. Making the LTO to be nano-sized can also improve the performance of the battery, thus we tried to synthesize LTO in nanorods form. LTO nanorods are synthesized by hydrothermal in NaOH 4 M solution. The LTO nanorods are mixed with various Sn (5wt%, 10wt%, and 15wt%) and 5wt% activated carbon. LTO nanorods/Sn-AC composite was characterized using XRD, SEM-EDS, and BET and the battery performance was analyzed by EIS, CV, and CD. The results showed that the highest capacity was obtained at LTO nanorods-AC/15wt% Sn with 127.24 mAh/g. This result shows that LTO nanorods-AC/15wt% Sn could be used as an alternative for anode component.
Simulation of Methanol Synthesis in Packed Bed Reactor for Utilization of CO2 from Acid Gas Removal Unit
Authors: Adji Bayu Sari , Muharam Yuswan , Kartohardjono Sutrasno
Published: November 2018

There are many oil and gas fields in Indonesia which contain high CO2 that need to be treated. The Acid Gas Removal Unit (AGRU) is installed to remove the CO2. The AGRU will release the CO2 gas from the regeneration column. It still contains a high concentration of CO2 (higher than 80%). The accumulation of CO2 emission to the atmosphere will impact the environment. To promote environment-friendly technology, the process can be improved with conversion of CO2 into methanol. It will provide a relatively closed loop of the carbon cycle and as a renewable energy alternative. This study aims to provide packed bed reactor design which can be implemented in the small-scale methanol production plant utilizing high CO2 feed gas. The reactor temperature was varied from 200°C to 250°C and pressure were operated in the range of 40 Bar up to 75 Bar. These variations were used to analyze the effects of methanol production. The simulation results showed that peak methanol production rate was achieved at the temperature around 230°C. As the conclusion, the reactor showed better performance at the higher pressure and higher temperature although the reaction is exothermic including the recycling process can reduce the cost of hydrogen.