bluuebunny/crossref_metadata_2025 huggingface dataset:
FACTORS AFFECTING THE LEACHING OF NITROGEN SPECIES FROM DIATOMACEOUS MUDSTONE
Authors: Igarashi Toshifumi , Ueda Takahiro , Hokora Hideyuki , Jo Mayumi , Kudo Hajime
Published: June 2024

Horonobe Underground Research Center, located in northern Hokkaido, Japan, has been excavating shafts and drifts of an underground research facility to establish general techniques for the assessment of deep geological environment. In this site, the groundwater seepage from the shafts and drifts as well as leachate from the excavated rock storage site contains high concentrations of total nitrogen. Ammonium-nitrogen (NH4-N), the major nitrogen species in the seepage and leachate, has been removed by a nearby treatment facility. However, NH4-N is easily oxidized to nitrite-nitrogen (NO2-N) and nitrate-nitrogen (NO3-N) by nitrification in the excavated rock storage site, which makes the removal process employed on site less effective. Therefore, column experiments that simulated the infiltration of rainwater through the storage site were carried out to understand the leaching and nitrification of nitrogen species and the factors affecting the phenomena. The results showed that the nitrification was inhibited when the rock layer was almost saturated, and that this process was temperature dependent. These indicate that nitrification can be mitigated by controlling hydrological conditions like water saturation.
SEPARATION OF ETHANOL-WATER MIXTURE BY PERVAPORATION WITH ORGANIC COMPOSITE MEMBRANE: MODELLING OF SEPARATION PERFORMANCE USING MODEL PARAMETERS DERIVED FROM EXPERIMENTAL DATA
Authors: Win Nwe Nwe , Bösch Peter , Friedl Anton
Published: June 2024

The permeation behavior of ethanol and water in pervaporation (PV) experiments using organic composite membrane; that is a polyvinyl alcohol (PVA) based active layer and a polyacrylo nitrile (PAN) supported layer was studied by measuring permeation flux and separation factor. The effects of permeate pressure (20-50 mbar), feed water concentration (5-1 wt%), and feed temperature (65-75 °C) were examined in this study. It was found that permeate pressure raised with reducing permeate flux and separation factor. Permeation flux enhanced and separation factor reduced with increasing feed water concentration and feed temperature. The solution-diffusion model that was derived by combination of Henry’s law of sorption and Fick’s law of diffusion was proposed to predict the solution-diffusion-desorption steps with a general driving force term and a permeation term. The activity coefficient of component in the ethanol water mixtures was calculated with UNIQUAC model. The solution-diffusion model was applied to predict the pervaporation flux through the PVA/PAN composite membrane. This model was successfully applied to the correlation of experimental results obtained with an organic composite membrane
UNDERSTANDING ARC-CONTINENT COLLISION AND CRUSTAL GROWTH: GEOCHEMISTRY OF PHILIPPINE SEDIMENTARY ROCK SEQUENCES
Authors: Dimalanta Carla , Yumul Jr. Graciano
Published: June 2024

This work synthesizes the results of studies utilizing whole rock sedimentary geochemistry of samples collected from different tectonic settings. Major, trace and rare earth element diagrams effectively discriminate the nature of the source rocks and tectonic setting of the sedimentary rocks. The continental character of Palawan, Buruanga and Mindoro are affirmed by their geochemical components which point to felsic and quartzose recycled source rocks in a continental setting. The Antique samples, when plotted on the various diagrams, are shown to have contributions from both mafic and felsic sources. This indicates their deposition in an overlap basin which marks province linking resulting from the collision of the two blocks – Palawan Microcontinental Block and Philippine Mobile Belt. In stark contrast, the sedimentary rocks from Baguio (Klondyke, Amlang and Cataguintingan) have geochemical signatures consistent with their derivation from mafic igneous rocks in an oceanic island arc setting. The variety of diagrams used in this study illustrates their effectiveness in characterizing the provenance and tectonic setting of sedimentary rocks. These results underscore the value of using whole rock sedimentary geochemistry in deciphering the evolution of the Philippine island arc system.
PATTERNED GROWTH OF SINGLE-WALLED CARBON NANOTUBES ON SILICON WAFER FOR ELECTRONIC DEVICES BY CHEMICAL VAPOR DEPOSITION PROCESS
Authors: Le Van Thang , ROUVIERE Emmanuelle
Published: June 2024

The ability to controllably obtain ordered carbon nanotube architectures is important for fundamental characterizations and potential applications of electrical devices. Controlling the synthesis process applied chemical vapor deposition (CVD) has been an effective technique to order single-walled nanotubes (SWNTs) on patterned catalyst. In this paper, single-walled carbon nanotubes are synthesized by chemical vapor deposition of methane at positioned locations on a silicon substrate. This synthetic approach has allowed individual SWNT to be grown from appointed surface sites by catalyst patterning and has led to interconnecting SWNT electrical devices. The combined synthesis and microfabrication technique presented here enable the developing of many ohmically contacted nanotube devices that can be controlled the size . Base on TEM results, SWNTs are formed via an open-ended, base-growth mechanism (VLS mechanism).
DIRECT CONVERSION OF BIOMASS TO ELECTRICITY WITH SOLID OXIDE FUEL CELL TECHNOLOGY
Authors: Shiratori Yusuke , Tran Quang-Tuyen , Sasaki Kazunari
Published: June 2024

Fuel cells are electrochemical devices that convert chemical energy of fuels directly into electrical energy without the Carnot limitation. Even in the smallest power range of less than 10 kW, fuel cells exhibit electrical efficiencies of 35-50 %LHV (lower heating value). Therefore, the fuel cell which can be operated with very low environmental emission levels, is regarded as a promising candidate for a distributed power source in the next generation. Although most fuel cells operate with hydrogen as a fuel, solid oxide fuel cells (SOFCs) operated in a high temperature range between 600 and 900oC accept the direct use of hydrocarbon fuels. Recently, the present research have demonstrated the stable operation of a direct internal reforming SOFC (DIRSOFC) operating not only on non-synthetic biogas over one month using an anode-supported button cell but also on practical palm-biodiesel over 800 h. Here, performances of DIRSOFCs operating on biogas are summarized and roadblocks to overcome for the realization of this type of highly-efficient carbonneutral fuel cell are discussed.
SIMULATION AND PIV EXPERIMENT OF THE DUCTED WATER CURRENT TURBINE AND EXTREMELY LOW HEAD HELICAL TURBINE
Authors: Phommachanh Sounthisack , Shinnosuke Obi , Sutikno Priyono , Soewono Aryadi
Published: June 2024

This research introduced for the Ducted Water Current Turbine Triple Helix with very low head less than 2m and water current at river or in the ocean, economical ecological use for small hydro power rating between 100 to 1000 kW still represent an unsolved problem. Unlike conventional hydro installation, water current turbine in open flow and generate power from flowing water with almost zero in environmental impact. Developments in water current turbine design are review and some potential advantages of duct or “diffuser augmented” current turbine and extremely low head turbine will be explored. For the output expected from the project is helical turbine with control flow on duct. The turbine design is based on the vertical turbine with helical blades. The basic idea of this research is optimized the helical turbine model, which is usually used in free stream (directly to the river stream line) can be apply with the situation inside the duct. And this research also tries to optimize the duct design. Therefore, get the better efficiency than the free stream flow turbine. The research aims to apply the helical turbine inside the duct to find the parameter of the power coefficient Cp against tip speed ratio λ. Parameters obtained from simulation in Fluent and through the experimental of the flow analysis by using PIV (Particle Image Velocimetry).
THE EFFECT OF SPECIFIC GRAVITY ON EMBEDDING STRENGTH OF GLUEDLAMINATED(GLULAM) BAMBOO: NUMERICAL ANALYSIS AND EXPERIMENT
Authors: Eratodi I Gusti Lanang Bagus , Triwiyono Andreas , Awaludin Ali , Prayitno Tibertius Agus
Published: June 2024

Glue-laminated (glulam) bamboo potentially used to be a substitute for wood as a building material, because it can be produced within four to five years of planting. Mechanical properties of glulam bamboo should be well understood by support the wider application of this new material in structural components. This study focused on embedding strength evaluation of glulam bamboo, were required to evaluate lateral resistance of dowel-type joints. The evaluation was carried out using experiment according to ASTM D5764 and numerical analysis performed with ADINATM. Material were considered in the experiment consist of bolt 12.2 mm diameter, a range of specific gravity of glulam bamboo from 0.57 to 0.79 and moisture contents varies from 11.14% to 12.45% were considered in the experiment. There were three groups of specimens: group A parallel loading to grain radial; group B parallel loading to grain tangential; and the last was group C perpendicular loading to grain. Glulam bamboo were modeled as an orthotropic nonlinear material whiles the dowel was assumed as perfectly rigid material. Contact condition between dowel and laminated bamboo was considered and the numerical model was solved under the plane stress assumption with deformation control. The experimental result was indicated that embedding strength parallel to grain (group A and B), it was significantly higher than group C. This phenomenon was apparent in the numerical study as well. The embedding strength of laminated bamboo (Fe) could be well predicted as 78.4G for parallel to grain radial, 72.79G for parallel to grain tangential; and 69.96G for perpendicular to grain radial, where G is the specific gravity.
STRENGTHENING OF STEEL AND CONCRETE COMPOSITE TRUSSES BY UNBONDED EXTERNAL PRESTRESSING
Authors: Chanvaivit Kanokpat , Limsuwan Ekasit , Dawe John
Published: June 2024

In this paper, the method of strengthening of steel and concrete composite trusses by using unbonded external prestressing was presented. Based on the experimental results compared with the analytical calculations, the structures are believed to perform better than the conventional composite trusses. The additional unbonded mono-strand external prestressing tendon of 7.9% of the tension bottom chord cross sectional area results in the 20% higher load carrying capacity. Moreover, there is the advantage of the additional prestressing to improve the accuracy of the flexural stiffness determination by using the transformed section method for the truss-like structural system. However, to maintain the ductile failure mode, the amount of the strengthening tendon should be limited for the required rotational capacity. In conclusion, this method can be useful in the upgrading of the existing composite trusses for both the flexural strength and serviceability.
A COMPARATIVE STUDY OF WETTABILITY RESPONSES OF POLYETHYLENE AND POLYMIDE SURFACES AFTER ION SHOWER TREATMENT
Authors: Amorsolo, Jr. Alberto , Flores Jose Cornelio , Miranda Eric
Published: June 2024

Surface modification of polymers can be achieved by their exposure to different plasma systems in order to improve surface properties such as wettability and adhesion in a manner that can preserve desirable bulk properties. The paper presents the results concerning wettability responses after surface modification of low density polyethylene (LDPE) and Kapton polyimide (PI), using a DC ion shower system. Plasma source gases included argon and nitrogen, and wettability of the polymer surface after treatment was quantified in terms of the contact angle exhibited by water droplets on the polymer surface. Plasma treatment parameters investigated were accelerating voltage, exposure time and chamber pressure. The vicinity of the most promising setting from the initial variable screening experiments which used argon and nitrogen was further investigated using single-factor experiments (minimum of three levels per factor) to pinpoint more precisely a setting that would yield a minimum contact angle. Results showed that LDPE appears to be more resistant to surface modification than Kapton polyimide.
STUDY OF ZnO and V2O5 NANOPARTICLES AS HETEROGENEOUS PHOTOCATALYSTS IN DEGRADING ORGANIC POLLUTANTS
Authors: Chan Yim Leng , Pung Swee Yong , Sreekantan Srimala
Published: June 2024

Heterogeneous photocatalysis particularly using semiconductor material to degrade organic compound is intensively studied in recent years. Semiconductors are good photocatalysts attributed to theirs light absorption properties, carrier charge transport characteristics and excited-state lifetimes. In this work, mixture of ZnO (3.23 eV) and V2O5 (2.38 eV) nanoparticles were used to degrade RhB solution under UV and visible light irradiation, respectively. The rod-like ZnO nanoparticles have an average diameter of 244.1 ± 94.5 nm whereas spherical-like V2O5 nanoparticles have an average diameter of 231.9 ±14.0 nm. Under UV light irradiation, pure ZnO nanoparticles have the highest photodegradation efficiency with rate constant of 0.034 ± 0.004 min-1 . This was attributed to its high reducing power of electrons and oxidation power of holes for producing free radicals. On the contrary, pure V2O5 nanoparticles demonstrated the highest photodegradation efficiency with rate constant of 0.013± 0.001 min-1 under visible light irradiation since it has profusion absorption in visible light region. The result provides useful guideline for designing a waste water purifier driven by sunlight for organic pollutants removal based on a mixture of wide bandgap and narrow bandgap semiconductor nanomaterials.
EVALUATION OF TSUNAMI EVACUATION ROUTES AT BENGKULU CITY INDONESIA USING NUMERICAL SIMULATIONS
Authors: Triatmadja Radianta , Nasution Sultan Sidik
Published: June 2024

Tsunami may attack Bengkulu City at any time. Although the City has prepared evacuation shelters and signboards at strategic locations to direct people to the shelters, the roads from the tsunami prone inundation areas that lead to the shelters should be evaluated to assure their reliability. A numerical simulation based on multi agents was used to study the routes’ capacity for evacuation during tsunami hazard. The approximated time available starting from the earthquake was 20 minutes. The first five minutes up to ten minutes were considered as the time for the government to state whether an evacuation was necessary or for the people to get ready for the evacuation. Five scenarios were tested. These were normal condition where the people were assumed to follow the existing evacuation sign boards, normal condition but with alternative direction of evacuation, a condition with obstacle during peak hour at a market, evacuation during night time, and a normal condition with increasing population. The simulation indicated that under normal condition, most of the people reached the shelter in less than 20 minutes. The alternative evacuation direction performs slightly better. The obstacles due to cars that were parked along the roads slightly increased the number of casualties. Evacuation scenario during the night time increased the casualties due to the limited vision especially along the lanes. The evacuation route should be well prepared especially during tsunami event in the future.
A PRACTICAL LIST OF CRITERIA FOR EVALUATING CONSTRUCTION PROJECT SUCCESS IN DEVELOPING COUNTRIES
Authors: Nguyen Thu Anh , Chovichien Visuth
Published: June 2024

Project success is a difficult concept because of the project’s complexity and dynamic. It is discussed a long time by many researchers. Until now, there is no accepted universal definition of project success, but no one can disclaim the importance of evaluating project success, especially in construction. Project success is a foundation to manage and control the current project, plan and orient the future project. In this paper, a practical list of criteria for evaluating project success is discussed. The final proposed framework is the result of both academic and practical point of view, from the solid foundation of literature review to the actual completed project information and document collected. The final indexes and sub-indexes in this list had to satisfy three criteria, which are high capacity to collect information, high level of importance, and high degree of applicability to evaluate project success. To achieve this objective, two surveys were performed. The first survey collected information from twenty-eight completed projects to consider the capacity to collect necessary information to evaluate project success. The second survey gathered opinions from sixty-five respondents about the importance level and applicability level of each index and sub-index. From analysis results, seven sub-indexes were eliminated from the list. The final list of criteria included eleven indexes which were clearly described by forty six sub-indexes.
THAI TRUCK LOADING MONITORING USING BWIM SYSTEM
Authors: Dounsuvanh Douangmixay , Pheinsusom Phoonsak , Sato Yasuhiko
Published: June 2024

Actual truck loads data is vital for bridge rating, and development of bridge design load. In Thailand, bridges have been designed using the HS20-44 design truck according to the AASHTO code; however, the actual truck loads are usually greater than the design truck load from the code. In addition, actual truck load are not available data to develop local truck load model for bridge design. This paper presents truck loads in Thailand that have been monitored using Bridge WeightIn-Motion (BWIM) system which innovated by author. Seven truck types are derived. Nominal analysis for simple span bridges shows that the heaviest Thai trucks induced forces are greater than that of the HS20-44 design truck.
ASSESSMENT OF AQUIFER SUSCEPTIBILITY DUE TO EXCESSIVE GROUNDWATER ABSTRACTION; A CASE STUDY OF YOGYAKARTA-SLEMAN GROUNDWATER BASIN
Authors: Putra Doni Prakasa Eka , Indrawan I Gde Budi
Published: June 2024

Yogyakarta-Sleman groundwater basin is one of productive groundwater basins in Indonesia. The groundwater basin is built by unconfined sand-aquifer system. Since the early 1980’s many schools, universities and hotels have been developed in this area to support education and tourism activities, and since the beginning of 2000’s the number of buildings has increased significantly. The development has resulted in a rapid rate of land use and population changes with the consequence of increasing groundwater pumping. Measurement results show that the rate of groundwater table degradation exceeds 0.5 m/year at some districts underlain by the groundwater basin. Because of this condition, it is necessary to assess the susceptibility of the aquifer to negative impacts due to the excessive groundwater pumping. The assessment was conducted by overlying factors such as aquifer response characteristics, aquifer storage characteristics, thickness of the aquifer, depth to groundwater table and distance from the sea. The assessment results show that the excessive groundwater abstraction to the aquifer has caused moderate to high susceptibility. It means that the groundwater pumping activities on this groundwater basin should be managed and controlled.
PROBABILISTIC SEISMIC HAZARD ASSESSMENT FOR YANGON REGION, MYANMAR
Authors: Thant Myo
Published: June 2024

According to the seismicity and the records of the previous considerably high magnitude earthquakes, Yangon Region can be regarded as the low to medium seismicity region. Moreover, tectonically the region is surrounded by the subduction zone between the Indian Plate and Burma Plate to the west and the right lateral Sagaing fault to the east. The most significant earthquake happened around this region is the Bago earthquake of 5th May, 1930 with the magnitude of 7.3. This earthquake caused 500 casualties and great destruction in Bago. However, considerable damage and 50 deaths were recorded in Yangon. It was originated from the Sagaing fault. The seismic hazard analysis is performed for Yangon Region by applying the probabilistic way. In conducting seismic hazard analysis, firstly the most possible seismic sources are identified and the seismic source parameters are then determined for each sources. Based on the seismicity, focal mechanism study of the previous events, and the geological data, the main seismic sources to cause the earthquake potentials for this region are subduction zone of Indian Plate beneath Burma Plate, Sagaing fault, and Kyaukkyan fault. Including those sources, thirteen areal seismic sources and two fault sources are identified. After that the seismic source parameters such as the seismicity parameters of a- and bvalues, maximum magnitude of earthquake potentials and earthquake recurrence parameters for certain magnitude of each seismic source are estimated. The seismic hazard analysis is carried out for 10% and 2% probabilities of exceedance in 50 years and the seismic hazard maps are represented in terms of peak ground acceleration and spectral acceleration at the periods of 0.2s and 1.0s for those recurrence intervals.
REVIEW OF TYPICAL BIOFUEL FOR AVIATION ALTERNATIVE FUEL PURPOSES
Authors: Reksowadojo Iman Kartolaksono , Duong Long , Pham Duc
Published: June 2024

Currently, along with ground used biofuel such as biodiesel, bioethanol has been utilizing widely over the world, alternative fuel for aviation purpose is increasing the consideration of researchers and governments as well as aviation industries. Several key priorities have been targeted for development aviation biofuel and three most important objectives have been identified which are decreasing fossil fuel reserves so that avoiding fluctuation of petroleum costs and reducing Greenhouse Gas (GHG) emissions. This paper presents a short review of researching activities in the field of aviation alternative fuel. Fatty Acid Esters (biodiesel or FAE), Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK) and Bio-derived Synthetic Paraffinic Kerosene (Bio-SPK) are the typical fuels. Research on physicochemical properties, ground engine test and flight demonstration were done by many authors as the investigation of using these biofuels for aviation. Research and development the biofuel for aviation promises a prospect and interesting work, however it also issues many challenges due to strict requirements of aviation fuel.
PLANNING ON WIND-DIESEL HYBRID MODEL FOR RURAL ELECTRIFICATION IN MYANMAR
Authors: Soe Thi Thi , Zheng Maosheng
Published: June 2024

Case study area, Wetkaik village (16° 54' N, 93° 27' E) is identified for economic feasibility in this paper. HOMER optimization model plan imputed from total daily load demand, 1167kWhr/day for current energy consuming of 850householdsandaverage wind speed, 3.7 m/s according to NASA data, 10m above the ground in this area is designed. This proposed system is storage wind-diesel hybrid system based on the cost and fuel availability, and resulting power quality for not only to optimize the energy cost but also to decrease the air pollution with effects the environment. Simulation results can be performed with HOMER micropower optimization tool. Special focus is put on sizing the optimal system which gives the lowest levelized cost of energy approximately 0.257 $/kWhr according to the village level priority. This project intends to access to a reliable supply of energy as wind-diesel hybrid system application that it is possible to supply of electricity to such remote locations where there is a wind energy source.
CRACKING OF USED VEGETABLE OIL MIXED WITH POLYPROPYLENE WASTE IN THE PRESENCE OF ACTIVATED CARBON
Authors: Sommani Piyanart , Mankong Noppol , Vitidsant Tharapong , Lothongkum Anchaleeporn Waritswat
Published: June 2024

With respect to high energy demand and increasing price of fossil fuels, alternative energy is a concerned issue worldwide. Waste cooking oils and plastic wastes are attractive as starting materials for value creation due to their high existing volumes and cost saving from waste treatment. Therefore, in this work, liquid fuel was synthesized by cracking of used vegetable oil (UVO) mixed with polypropylene waste (PP) in the presence of activated carbon from coconut shell. The reactions were studied at a constant hydrogen pressure of 0.1 MPa in a batch reactor. The weight ratios of used vegetable oil and polypropylene waste were varied at 30 : 70, 50 : 50 and 70 : 30 with activated carbon to raw materials ratios of 2.5 and 5 wt% at the reaction temperature of 390 and 430°C, and reaction time of 30 and 60 mins. The amounts of gas, liquid and solid fractions were analyzed. The highest yield of total liquid hydrocarbon product was attained at a ratio of used vegetable oil to polypropylene waste of 30 : 70 wt% with activated carbon to raw materials ratios of 2.5 wt%, reaction temperature of 430°C and reaction time of 30 mins. Under these conditions, gas, liquid and solid fractions of 19.56, 79.69 and 0.75 wt% were observed. The distribution of oil fractions in liquid product was analyzed by the simulated distillation gas chromatography based on ASTM D2887, which is the standard test method for the boiling-range distribution of petroleum fractions. It was comprised of naphtha, kerosene, light gas oils, heavy gas oils and long residue of 33.20, 14.62, 19.72, 2.49 and 9.66 wt%, respectively.
ACTIVATED CARBON FIBER DERIVED FROM SINGLE STEP CARBONIZATION-ACTIVATION PROCESS
Authors: Ooi Chee-Heong , Lee Ting , Pung Swee-Yong , Yeoh Fei-Yee
Published: June 2024

The properties of activated carbon are influenced by the conditions of carbonization and activation. Activated carbon is normally produced through a conventional two-step process. This two-step process comprises the carbonization of precursor followed by activation of the carbonaceous char at elevated temperatures with the presence of suitable oxidizing gases. However, such process is very time consuming and energy intensive. The present study attempted to synthesize activated carbon fiber (ACF) derived from oil palm empty fruit bunches (EFB) fiber by using single step activation process. The properties of the produced ACF were investigated and analyzed by SEM, EDS, FTIR and XRD. Nitrogen adsorption was carried out to characterize the porosity of the produced ACF. EDS results indicated the carbon content of raw oil palm EFB fiber was 63.33 wt % with oxygen content of 36.67 wt %. After activation, ACF has a higher carbon content of 93.63 wt % and oxygen content of 5.19 wt %. The BET and Langmuir surface area for the produced ACF were 432 m2/g and 670 m2/g, respectively. The results revealed the possibility to prepare ACF from oil palm EFB fiber by using single step activation process.
EVALUATING THERMAL PROPERTIES OF GEOPOLYMER PRODUCED FROM RED MUD, RICE HUSK ASH AND DIATOMACEOUS EARTH
Authors: Nguyen Hoc Thang , Gallardo Susan Manalastas , Bacani Florinda , Hinode Hirofumi , Do Quang Minh , Promentilla Michael Angelo
Published: June 2024

In this paper, thermal properties of geopolymer from the mixture of red mud, rice husk ash, and diatomaceous earth were investigated. Red mud is an industrial waste from bauxite plants which has a negative impact to the environment if not properly managed, especially for countries mining this bauxite ore. On the other hand, rice husk ash is an agricultural waste abundant in Asian countries whereas diatomaceous earth is a natural mineral locally abundant in some parts of Vietnam. In this study, red mud was mixed with rice husk ash and diatomaceous earth at high alkaline condition to synthesize geopolymer, an inorganic polymer materials produced from geopolymerization reactions forming the alumino-silicate network. For thermal specifications of the geopolymer products, thermal conductivity, the thermal expansion and thermal gravimetric (TG) values from room temperature to 950 oC are measured. For example, the coefficient of thermal conductivity at room temperature was measured around 0.5 W/m-K, the coefficient of thermal expansion around 950 oC is in range of 5.71x10-6 K-1 to 12.42x10–6 K–1 and TG at 950 oC is below 10%. Response surface method was also used to determine the thermal properties of geopolymer as a function of mix proportions of raw materials. The study also investigated the changes of microstructure when the geopolymer is subjected to high temperature via X-ray diffraction (XRD) and scanning electron microscopy (SEM).
HYDRODYNAMIC INVESTIGATION OF A SHALLOW TROPICAL LAKE ENVIRONMENT (LAGUNA LAKE, PHILIPPINES) AND ASSOCIATED IMPLICATIONS FOR EUTROPHIC VULNERABILITY
Authors: Herrera Eugene , Nadaoka Kazuo , Blanco Ariel , Hernandez Emiterio
Published: June 2024

In this study, a three-dimensional (3D) hydrodynamic model was developed to investigate the water circulation characteristics of a shallow tropical lake environment (Laguna Lake, Philippines) under varying wind stress, watershed river discharge, and sea interaction (Manila Bay, Philippines) to elucidate hydrodynamic implications to eutrophic vulnerability. The analyses were based on field observations and numerical simulations covering long-term periods (dry and wet season) and intensive field measurements. The results demonstrated different circulation patterns and vertical current regimes in time and space that accentuated a thermally stratified lake environment in spite of a shallow water depth (2.5 meter average). In the wet season, current movement is generally toward Pasig River, the lake’s only outlet, with embayment water mass moving in the clockwise direction. The dry season lake flow pattern was characterized by counter-clockwise gyre circulations, Pasig River backflow, and salinity intrusion. Wind forces showed strong influence on lake hydrodynamics due to the complex surrounding topography, steep land-lake thermal difference, regular passage of tropical storms and typhoons, and shifts in the monsoon wind direction. The resulting mixed layer hydrodynamics revealed important implications to the planktonic movement, nutrient recycling, and primary production of the lake. Long term continuous observations and numerical analyses also demonstrated the intrusion of seawater to Laguna Lake that potentially adds to its eutrophic vulnerability with the associated entry of nutrient and microorganism-rich polluted waters from Metro Manila
IMPROVED REMOVAL OF COPPER IONS FROM AQUEOUS SOLUTION USING NaOH-PRETREATED COCO PEAT
Authors: Diola Ma. Brida Lea , Orozco Christian
Published: June 2024

This study aims to analyze the effect of chemical pretreatment using sodium hydroxide (NaOH) on the capacity of coco peat in removing of copper (II) ions from aqueous solutions. The effects of varying the molarity of NaOH, the solution pH, initial Cu(II) concentration, coco peat dosage and contact time were studied in batch experiment. The result of the preliminary pretreatment study shows that treatment with 0.5M NaOH greatly enhanced the metal sorption capacity of raw coco peat. The uptake capacity for Cu of the raw coco peat was increased from 46% to 83% at pH 4.0 and from 15% to 27% uptake for initial solution pH of 2.4. The results showed that the removal rate is directly proportional to pH, coco peat’s dosage and contact time and inversely proportional to Cu(II) concentration. The adsorption process is best explained by the Langmuir isotherm than the Freundlich isotherm, indicating monolayer adsorption on a homogenous surface. The rate of reaction follows the pseudo-second order kinetic model, signifying that chemisorption is the ratelimiting mechanism. The results of the Fourier Transform Infra-Red (FTIR) analysis indicated that the main functional groups involved in the sorption of copper to NaOH pretreated coco peat are the hydroxyl, carboxyl and phenolic groups. Based on the results of this study, it was found that pretreating coco peat with NaOH significantly improve the overall efficiency of coco peat in removing Cu(II) by adsorption process.
INVESTIGATING LEACHATE CONTAMINATION NEAR THE QUEZON CITY CONTROLLED DUMPING FACILITY (QCCDF) USING CHLORIDE ION AS INDICATOR
Authors: Tanchuling Maria Antonia , Cayabyab Inla Diana , Takemura Jiro
Published: June 2024

The Quezon City Controlled Dumping Facility (QCCDF) has been the main disposal site of Quezon City, the largest city within Metro Manila since the 1970s. With the huge volume of wastes received every day and with no protective liner on the old mound and creeks directly connecting the facility to Marikina River, the main river system in eastern Metro Manila, surface and groundwater contaminations have been a critical concern. The main objective of the study is to determine the effect of the disposal site on the surface water and groundwater quality by evaluating the water quality at different points in and around the landfill. Secondarily, it aims to investigate correlations between the water quality parameters as well as determine any seasonal effects on the water quality. Sampling points from wells on and around the facility were collected for six months covering dry and wet season using Horiba water quality monitoring equipment and CHEMetrics V-2000 Photometer. Leachate quality parameters pH, turbidity, DO, and chloride are not affected by the change in seasons as evidenced by statistical t-tests. Temperature is higher during the wet season, while TDS is lower at this time which may be attributed to dilution due to rainfall. DO and turbidity in leachate is strongly negatively correlated, while temperature and Clin leachate are positively correlated. In groundwater, the change in season affects temperature, TDS and chloride concentrations. This trend is not evidenced in pH and turbidity. TDS and chloride are correlated with each other. Based on the surface water quality measurements, temperature, pH, DO, and TDS are affected by the change in season while turbidity and chloride are not, based on the comparison of samples taken from different locations. Aside from strong correlation of Clˉ and TDS, as seen in groundwater, very strong correlations are also observed between Clˉ and DO, and TDS and DO. Using chloride ion as indicator of leachate, the study reveals that the leachate tends to spread downward towards Marikina River. Based on the comparison of chloride concentrations near the outfall of the leachate creek at Marikina River, it can be seen that the release of leachate at the river impacts the river as evidenced by an increase in chloride concentration downstream of the outfall.
INFLUENCE OF E10, E15 AND E20 FUELS ON PERFORMANCE AND EMISSIONS OF IN-USE GASOLINE PASSENGER CARSOF E10, E15 AND E20 FUELS ON PERFORMANCE AND EMISSIONS OF IN-USE GASOLINE PASSENGER CARS
Authors: Truyen Pham Huu , Tuyen Pham Huu , Tuan Pham Minh , Tuan Le Anh
Published: June 2024

The use of ethanol/gasoline blends on gasoline engines is not only a potential solution for satisfying the fuel demand but also for reducing emissions from vehicles which cause environmental pollution and adverse health effect. In Vietnam, the blend with 5% of ethanol (E5) has been widely used. However, blends with higher than 5% of ethanol should be studied and applied in order to improve the ability to substitute for gasoline. This paper presents the experimental results of in-use carbureted and fuel injected passenger cars fueled by gasoline RON92, E10, E15 and E20. These cars were tested at the steady state as well as following the ECE15+EUDC driving cycle. Results indicated the different influence of these ethanol/gasoline blends on power, fuel consumption and emissions of the cars.
ALTERATION, ORE MINERALOGY, AND FLUID INCLUSION MICROTHERMOMETRY OF THE RORAH KADAL QUARTZ VEIN IN CIBALIUNG GOLDFIELD, WESTERN JAVA, INDONESIA
Authors: Haryanto Agus Didit , Rosana Mega Fatimah , Tindell Thomas , Gabo Jillian Aira Sibal , Yusuf Haris , Yonezu Kotaro
Published: June 2024

The Rorah Kadal vein is located in the Cibaliung goldfield, Western Java, Indonesia. The vein is hosted by the Miocene Honje Igneous Complex and composed of sequences of basalt-andesite lava flows, volcanic breccia, and overlain by tuff. The paper is tending to describe occurrence, alteration, mineralogy, and fluid inclusion microthermometry of the Rorah Kadal gold-bearing quartz vein to understand the process and formation condition of gold mineralization. The Rorah Kadal is a single vein trending NW direction and about 700 meters parallel to main Cibaliung vein. The alteration consists of illite/smectite mixed layer mineral-adularia-quartz, chlorite-chlorite/smectite mixed layer mineral, and illite-illite/smectite mixed layer mineral-calcite-quartz zones. The vein types are colloform-crustiform band, breccia, vug, cockade, and comb, which are mainly composed of quartz and adularia. Based on quartz textures, three stages of mineralization are recognized: Stage-1 colloform-crustiform; Stage-2 hydrothermal breccia; and Stage 3- late stage quartz veinlet textures. The ore mineralogy of the Rorah Kadal quartz vein is mainly pyrite, chalcopyrite, galena, sphalerite, electrum, and aguilarite. Fluid inclusion temperatures from five drill core quartz samples ranges from 180 to 330 °C, with salinities varying from 1.2 to 4.0 wt% NaCl. The Rorah Kadal vein has slightly high fluid temperature and salinity as compared to Cikoneng and Cibitung veins of the Cibaliung goldfield. This data suggests that the hydrothermal fluids appear to have formed from low temperature and low salinity fluids in near neutral pH environment.
EXPERIMENTAL STUDY ON FLOW AND THERMAL CHARACTERS OF CALCIUM CHLORIDE HYDRATE SLURRY
Authors: Suwono Aryadi , Irsyad Moh , Indartono Yuli Setyo , Pasek Ari Darmawan
Published: June 2024

Phase change material has been used as secondary refrigerant mixing ingredients to reduce energy consumption. Salt hydrate from calcium chloride with the composition of 55% calcium chloride dihydrate and 45% water matched with the temperature of chiller evaporator. Flow of slurry has given effect on the flow and heat transfer characteristics. Equipment used to know this is double pipe heat exchanger with flow counter flow. Pipe material is copper. The test results showed that the temperature salt hydrate containing solid particles. Salt hydrate slurry can improve the heat transfer coefficient, but the pressure drop and friction factor was also increased.
PRETREATMENT AND OPTIMIZATION STUDIES ON THE EXTRACTION OF ANTIOXIDANT COMPONENTS FROM PHALERIA MACROCARPA FRUIT
Authors: Yayah Winawaty , Hudaya Tedi , Prasetyo Susiana , Wangsa Julie
Published: June 2024

Phaleria macrocarpa, one of many indigenous Indonesian plants, possesses potent antioxidant activity and hence may serve as natural food preservative, cosmetic ingredients, as well as food supplement. This study is the second stage of a three-year project to isolate antioxidant components in Phaleria macrocarpa for natural preservative application. The objective of this study is to investigate the effect of pretreatment process on the oleoresin and bioactive content, and to optimize three parameters in the extraction process, i.e. ethanol concentration, F/S ratio, and temperature. The selected pretreatment method was solid-liquid extraction using a non-polar solvent (n-hexane) and a semi polar solvent (ethyl acetate). The pretreatment process produced less sticky oleoresin, especially with n-hexane, due to significant removal of tannin, and had only a little effect (less than 4%) on the antioxidant activity and flavonoid content. However, the pretreatment indeed reduced the yield of oleoresin by around 10%. Three important parameters of the extraction process were optimized using Central Composite Experimental Design by varying operation temperature from 27.5 °C to 64.5 °C, F/S ratio from 1 : 11.5 g/mL to 1 : 53.5 g/mL, and ethanol concentration from 14 %-v/v to 93 %-v/v. The response surface analysis showed a maximum point at ethanol concentration of 30 %-v/v, F/S ratio of 1 : 45 g/mL, and temperature at 57 ºC which gave the oleoresin yield of 1.00 g oleoresin/g dry feed and antioxidant activities of 2.99 μmol DPPH/mg oleoresin.
SOIL REINFORCEMENT USING CALCIUM PHOSPHATE COMPOUNDS
Authors: Kawasaki Satoru , Akiyama Masaru
Published: June 2024

For the purpose of using calcium phosphate compounds (CPCs) for ground improvement measures, such as the reinforcement of soils and rocks, a fundamental examination of new grouting materials composed of CPCs (CPC-Chem) is required. Therefore, in this study, we have first analyzed the ideal conditions for CPC precipitation by in vitro examination of the different mixtures of calcium and phosphate stock solutions. Following that, Toyoura sand was cemented with CPCs and the cured specimens were analyzed by using unconfined compressive strength (UCS) tests. Similarly, Toyoura sand was cemented with a mixture of CPC-Chem and tricalcium phosphate (TCP) powder and then cured; these specimens too were then analyzed by using UCS tests. Test results indicate an improvement in UCS of TCP-added specimens when compared to that of no-additive (CPCChem alone) specimens. Besides, the morphology and elemental composition of the specimens were analyzed by using scanning electron microscopy (SEM) and energy dispersive X-ray fluorescence spectroscopy (EDX). The results obtained from the systematic analyses indicate the practical feasibility of using both the combination of CPC-Chem and TCP powder as well as the CPC-Chem alone as chemical grouts for ground improvement measures.
COASTAL COMMUNITY’S RESPONSES TO WATER INFRASTRUCTURE UNDER CLIMATE-RELATED DISASTER IN SEMARANG CITY, INDONESIA
Authors: Wijaya Nurrohman
Published: June 2024

Rapid urbanization in developing countries faces the challenge of increasing demand for urban water services. This challenge can be more significant particularly in urban coastal area under climate-related disaster, which is able to obviously influence the change of socioeconomic and environmental aspects. This study investigates the affected coastal community’s responses to water infrastructure under climate-related disaster in Tanjung Mas, located in the northern part of Semarang City, Central Java Province, Indonesia. Field observation, key informants interview, and structured household survey were conducted. The survey was conducted among 106 residents using random sampling method. The findings reveal that water infrastructure is mostly available in the study area and the residents typically rely on water source from the local water company by using water supply pipeline. However, the location in flood prone area has contributed enormously their vulnerability to water availability. The residents recognize the importance of water for their quality of life, and the impacts of urban development to reduce the availability of water resource, but they had not completely understood the relationship between climate change and water sector. They have perceived that climate change is not significant issue related to water resource, even though they live in prone area. The practice of their current measures is only able to cope with the impacts in the short term period, such as clearing drainage channels, adding sanitation infrastructure, and building simple embankment. Public awareness campaign and advocacy at the community level are necessary to reduce the low perception of potential risks posed by climate change and natural disasters related to water infrastructure. The specific government policy, program and practice oriented solutions on climate change and urban development issues need to be considered in order to increase resilience and sustainable urban development.
FACTORS INFLUENCING O N SAFETY MANAGEMENT STATUS AND EVALUATIONOF SAFETY MANAGEMENT STATUS IN CONSTRUCTION PROJECTS IN CAMBODIA
Authors: Jokkaw Noppadon , Tongthong Tanit
Published: June 2024

The objectives of this paper are to present the factors influencing on safety management (SM) status and the evaluation of safety management status in construction projects in Cambodia. The probability of factors affected to safety management status were explored by interviewing both local and international contractors. The status of safety management in construction sites were evaluated by the probability of the factors used for the safety management that were obtained from construction the site observation and the interviews with evidences presented. The status of safety management was classified into five levels by ranges of the probability. The results of this research show that the probability of the factors influencing the safety management in construction sites of both local and international contractors were divided into two groups, including the high probability and low probability groups. The nine factors in high probability groups were accepted that they can influence on the safety management in construction site such as budget allocated for safety management, safety policy, awareness of project managers, safety training, safety organization, safety regulation, usage of personal protective equipments (PPE), site-accident investigation, and safety committee. The results were accepted based on the reliability of the data set from the respondents that were verified by Cronbach’s Alpha (α ≥0.6). Moreover, the status of safety management in construction sites of the international contractors was better than the local contractors since the probability of all factors used for the safety management in construction sites of the international contractors were in medium level, high level, and very high level. On the other hand, for the local contractors, the probability of all factors used for the safety management in construction sites were in medium level, low level, and very low level that they have been required for improvement.
The finite type of modules of bounded projective dimension and Serre's conditions
Authors: Hrbek Michal , Le Gros Giovanna
Published: June 2024

Let be a commutative Noetherian ring. For a natural number , we prove that the class of modules of projective dimension bounded by is of finite type if and only if satisfies Serre's condition . In particular, this answers positively a question of Bazzoni and Herbera in the specific setting of a Gorenstein ring. Applying similar techniques, we also show that the ‐dimensional version of the Govorov–Lazard theorem holds if and only if satisfies the ‘almost’ Serre condition .