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Articles 841 - 870 of 1105

Full-Text Articles in Civil Engineering

Linking Water Resource Network Models To An Open Data Management Platform, Phillipp Meier, Stephen Knox, Julien Harou Jun 2014

Linking Water Resource Network Models To An Open Data Management Platform, Phillipp Meier, Stephen Knox, Julien Harou

International Congress on Environmental Modelling and Software

The development of models for complex water resources systems frequently involves cus- tomising model formulations to fit unique institutional or physical problems. Linking existing model components is part of this process. As an alternative to pre-packaged models or building models based on components that comply to the same standard interface we present a model platform where network resource models (water, energy, transport, etc.) are linked to a data manager in a generic way. A modular architecture is achieved using a server for data storage. Clients connecting to the server, called Apps, provide import and export functions from and to various …


Multiscale Spatial Sensitivity Analysis For Agent-Based Modelling Of Coupled Landscape And Aquatic Systems, Arika Ligmann-Zielinska, Wei Liu, Daniel B. Kramer, Kendra Spence Cheruvelil, Patricia A. Soranno, Piotr Jankowski, Seda Salap Jun 2014

Multiscale Spatial Sensitivity Analysis For Agent-Based Modelling Of Coupled Landscape And Aquatic Systems, Arika Ligmann-Zielinska, Wei Liu, Daniel B. Kramer, Kendra Spence Cheruvelil, Patricia A. Soranno, Piotr Jankowski, Seda Salap

International Congress on Environmental Modelling and Software

Models of coupled landscape and aquatic systems (CLAS) are prone to input uncertainties that vary over space. To address this challenge, we employ a comprehensive model evaluation that: [1] quantifies the variability of model results (uncertainty analysis), and [2] decomposes this variability based on the relative contribution of inputs to identify major drivers in the model (sensitivity analysis). Our study simulates how agricultural land conversion from active to fallow lands reduces nutrient loading to lakes. We employ an agent-based model of farmer decision making coupled with a spatially-explicit biophysical lake model. A number of model inputs are uncertain including: variables …


Defining The Spatiotemporal Surveillance Space For Alien Species' Invasions Using Approximate Bayesian Computation, Grant Hamilton, Rune Rasmussen, Jana Mullerova, Jan Pergl, Petr Pysek Jun 2014

Defining The Spatiotemporal Surveillance Space For Alien Species' Invasions Using Approximate Bayesian Computation, Grant Hamilton, Rune Rasmussen, Jana Mullerova, Jan Pergl, Petr Pysek

International Congress on Environmental Modelling and Software

The spatiotemporal dynamics of an alien species invasion across a real landscape are typically complex. While surveillance is an essential part of a management response, planning surveillance in space and time present a difficult challenge due to this complexity. We show here a method for determining the highest probability sites for occupancy across a landscape at an arbitrary point in the future, based on occupancy data from a single slice in time. We apply to the method to the invasion of Giant Hogweed, a serious weed in the Czech republic and throughout Europe.


The Effect Of Recovery On Modeling Inactivation Of Bacillus Spores On Hvac Filters, Bharathi Murali, Jade Mitchell Jun 2014

The Effect Of Recovery On Modeling Inactivation Of Bacillus Spores On Hvac Filters, Bharathi Murali, Jade Mitchell

International Congress on Environmental Modelling and Software

The ability of microorganisms to persist on fomite surfaces is an important component in modeling their spread in physical environment. For example, Bacillus anthracis (Ba) spores have been found to be extremely resistant to inactivation, environmental stresses, and stable over decades. Modeling the inactivation of spores could form an integral element for estimating the exposure and the subsequent health risks posed by them. However, there is a knowledge gap in the quantification of recovery of Bacillus spores on porous surfaces, which may have a significant effect on the quantification of their persistence in the environment. Our work investigates the recovery …


A K-Means Clustering Approach To Assess Wheat Yield Prediction Uncertainty With A Hydrus-1d Coupled Crop Model, Derek Groenendyk, Kelly Thorp, Ty Ferré, Wade Crow, Doug Hunsaker Jun 2014

A K-Means Clustering Approach To Assess Wheat Yield Prediction Uncertainty With A Hydrus-1d Coupled Crop Model, Derek Groenendyk, Kelly Thorp, Ty Ferré, Wade Crow, Doug Hunsaker

International Congress on Environmental Modelling and Software

Soil moisture, especially under drought conditions, is a factor that is known to impact crop yield predictions. Crop growth models used to make these predictions rely on soil texture estimates, which influence simulated soil moisture and ultimately crop growth. The purpose of this research was to implement a k-means clustering approach to address the uncertainty of the soil texture estimates. By grouping similar soil textures based on their simulated responses, clustering reveals how soil texture uncertainty may impact yield estimates. Wheat growth simulations were conducted using a HYDRUS 1D and coupled crop model for soils defined on the USDA soil …


Gis-Based Environmental Modeling With Tangible Interaction And Dynamic Visualization, Anna Petrasova, Brendan Harmon, Vaclav Petras, Helena Mitasova Jun 2014

Gis-Based Environmental Modeling With Tangible Interaction And Dynamic Visualization, Anna Petrasova, Brendan Harmon, Vaclav Petras, Helena Mitasova

International Congress on Environmental Modelling and Software

We present a new, affordable version of TanGeoMS, a tangible geospatial modeling and visualization system designed for collaboratively exploring how terrain change impacts landscape pro­ cesses. It couples a physical, three-dimensional model of a landscape with geospatial modeling and analysis through a cycle of scanning and projection. Multiple users can modify the physical model by hand while it is being scanned; by sculpting the model they generate input for modeling of geophysical processes. The modeling results are then visualized by projecting images or animations back on the physical model. This feedback loop is an intuitive way to evaluate the impacts …


Calibration Of Simulation Platforms Including Highly Interweaved Processes: The Maelia Multi-Agent Platform, Romain Lardy, Pierre Mazzega, Christophe Sibertin-Blanc, Yves Auda, José-Miguel Sanchez-Perez, Sabine Sauvage, Olivier Therond Jun 2014

Calibration Of Simulation Platforms Including Highly Interweaved Processes: The Maelia Multi-Agent Platform, Romain Lardy, Pierre Mazzega, Christophe Sibertin-Blanc, Yves Auda, José-Miguel Sanchez-Perez, Sabine Sauvage, Olivier Therond

International Congress on Environmental Modelling and Software

The MAELIA project develops an agent-based modeling and simulation platform to study the environmental, economic and social impacts of various regulations regarding water use and water management in combination with climate change. An integrated modelling approach has been used to model the investigated social-ecological system. MAELIA combines spatiotemporal models of ecologic (e.g. water flow and plant growth) and human decision-making processes (e.g. cropping plan), socio-economic dynamics (e.g. land cover changes). Due to the diversity and the interweaving of the processes considered, the calibration and evaluation of such a multi-agent platform is a scientific challenge. Indeed, many parameters can reveal to …


An Environmental Modeling Language For Agents And Fields, Kor De Jong, Merijn De Bakker, Derek Karssenberg Jun 2014

An Environmental Modeling Language For Agents And Fields, Kor De Jong, Merijn De Bakker, Derek Karssenberg

International Congress on Environmental Modelling and Software

Environmental modeling involves manipulating environmental attributes represented in soft­ware by agents, fields or both, but most modeling environments are designed to be especially useful for either agent-based or field-based modeling. Agent-based and field-based modeling environments have different properties with respect to their ease of use and how well both agents and fields can be represented and manipulated. Most agent-based modeling environments require the modeler to use a general purpose object oriented programming language like Java to express models, while field-based modeling environments often implement a high level, domain specific imperative language based on map algebra, or extent a general purpose …


An Integrated Approach For Including Social Capacities, And Economic Valuation In Risk Assessment Of Water Related Hazards In Uncertain Scenarios, Carlo Giupponi, Vahid Mojtahed, Animesh K. Gain, Stefano Balbi, Claudio Biscaro Jun 2014

An Integrated Approach For Including Social Capacities, And Economic Valuation In Risk Assessment Of Water Related Hazards In Uncertain Scenarios, Carlo Giupponi, Vahid Mojtahed, Animesh K. Gain, Stefano Balbi, Claudio Biscaro

International Congress on Environmental Modelling and Software

We propose a conceptual framework, KR-FWK (i.e. KULTURisk Framework from the name of the European project within which it originated) and its implementation methods SERRA (Socio-Economic Regional Risk Assessment) for integrated (physical and economical) risk assessment, and economic valuation of risk prevention benefits on multiple receptors. The KR-FWK and the SERRA approach are characterised by: (i) integration of physical-environmental dimensions and the socio-economic ones in risk assessment; (ii) consideration of the role of social capacities (adaptive and coping capacity) in reducing risk and related costs, (iii) quantitative (even monetary) assessment of risks and of the benefits of risk reduction measures, …


Agile Workflows For Climate Impact Risk Assessment Based On The Ci:Grasp Platform And The Jabc Modeling Framework, Samih Al-Areqi, Anna-Lena Lamprecht, Tiziana Margaria, Steffen Kriewald, Dominik Reusser, Markus Wrobel Jun 2014

Agile Workflows For Climate Impact Risk Assessment Based On The Ci:Grasp Platform And The Jabc Modeling Framework, Samih Al-Areqi, Anna-Lena Lamprecht, Tiziana Margaria, Steffen Kriewald, Dominik Reusser, Markus Wrobel

International Congress on Environmental Modelling and Software

Analyzing and assessing potential impacts of climate change are critical and challenging tasks that require the processing of large and heterogeneous datasets. These analyses are particularly demanding because of the multi-scale and multi-objective nature of environmental modeling for climate change impact assessment. The Climate Impacts: Global and Regional Adaptation Support Platform (ci:grasp) is a web-based climate information service for exploring climate change related information in its geographical context. In this paper, we show how the agile workflow development style supported by the jABC process modeling and execution framework permits us to leverage the processes implemented in the ci:grasp platform to …


The Data Processing Inequality And Environmental Model Prediction, Steven V. Weijs Jun 2014

The Data Processing Inequality And Environmental Model Prediction, Steven V. Weijs

International Congress on Environmental Modelling and Software

Prediction in environmental systems, such as hydrological streamflow prediction, is a challenging task. Although on a small scale, many of the physical processes are well described, accurate predictions of macroscopical (e.g. catchment scale) behavior with a bottom-up mechanistic approach often remains elusive. On the other hand, conceptual or purely statistical models fitted to data often perform surprisingly well for prediction. The data processing inequality, from the field of information theory, says that processing data with statistical procedures can only decrease, and not increase the information content of the data. This seems to contradict the intuition that our knowledge of physical …


Managing Agricultural Landscapes For Favouring Ecosystem Services Provided By Biodiversity: A Spatially Explicit Model Of Crop Rotations In The Gama Simulation Platform, Hugo Thierry, Aude Vialatte, Jean-Philippe Choisis, Benoit Gaudou, Claude Monteil Jun 2014

Managing Agricultural Landscapes For Favouring Ecosystem Services Provided By Biodiversity: A Spatially Explicit Model Of Crop Rotations In The Gama Simulation Platform, Hugo Thierry, Aude Vialatte, Jean-Philippe Choisis, Benoit Gaudou, Claude Monteil

International Congress on Environmental Modelling and Software

The need to reduce the use of pesticides in agricultural ecosystems requires studying and developing new pest regulation methods. Individual-based models are useful to better understand how dynamics of insects interact with agricultural landscapes and to study the potential effects of alternative regulation methods, taking into account the spatial and temporal stochasticity of agricultural ecosystems caused by human management. Crop rotations and crop phenology have an important impact on the life cycles of populations of insects. We developed an individual-based model simulating the dynamics of an agricultural landscape from GIS data. The spatiotemporal stochasticity is simulated using typical landcover rotations …


Dynamic Characteristic Identification Of Seismic-Excited Multi-Story Buildings Through Response-Only Technique, Agung Budipriyanto, Priyo Suprobo Apr 2014

Dynamic Characteristic Identification Of Seismic-Excited Multi-Story Buildings Through Response-Only Technique, Agung Budipriyanto, Priyo Suprobo

Makara Journal of Technology

Identifying dynamic characteristics of civil engineering structures is still a challenging task. It intends to assess behavior of the structures under time-dependent loads. This paper discusses a methodology suitable for identifying the characteristics of multi-story buildings using only their measured response under earthquake ground excitations. Appropriateness of technique used for structural identification was corroborated through coherence of the structure’s responses. The methodology was applied for identifying the characteristics of 14-story and 20-story office buildings located in a high seismic region. Responses of these two buildings recorded during three different seismic ground motions were investigated. The buildings’ response spectral densities and …


Synthesis And Characterization Of Soy-Based Polyurethane Foam With Utilization Of Ethylene Glycol In Polyol, Flora Elvistia Firdaus Apr 2014

Synthesis And Characterization Of Soy-Based Polyurethane Foam With Utilization Of Ethylene Glycol In Polyol, Flora Elvistia Firdaus

Makara Journal of Technology

The use of vegetable oils on replacing petroleum has attracted attention of many researchers. The chemical structure of vegetable oils are different from petrochemicals, so the structure of soybean oil has to be chemically modified through its unsaturated fatty acid chain in triglyceride. A two step process was conducted for the preparation of soy-polyol in designated temperatures; 50 °C, 60 °C, and 70 °C. Ethylene glycol (EG) as co-reagent was taking part in soy-polyol synthesis, and the soy-polyol was used as a sole polyol for polyurethane synthesis. Referred to the previous study, the existence of EG in polyurethane synthesis can …


Performances Of Free-Space Optical Communication System Over Strong Turbulence, Ucuk Darusalam, Purnomo Sidi Priambodo, Harry Sudibyo, Eko Tjipto Rahardjo Apr 2014

Performances Of Free-Space Optical Communication System Over Strong Turbulence, Ucuk Darusalam, Purnomo Sidi Priambodo, Harry Sudibyo, Eko Tjipto Rahardjo

Makara Journal of Technology

We report an experimental of free-space optical communication (FSOC) system that use tube propagation simulator (TPS) as the turbulence medium. The FSOC system use wavelength of 1550 nm at the rate transmission of 1000 Mbps and amplified with EDFA at the output of +23 dBm. Index structure of 10-15–10-13 as the representation of atmosphere index turbulences are used for simulation of intensity distribution model or scintillation. The simulation use gammagamma and K model as well. The beam wave propagation models used in simulation are plane wave, spherical wave and Gaussian wave. Spherical wave achieves highest performance via gamma-gamma in strong …


Preparations Of Nanostructured Silicide Bundles And Oxide Arrays, Hirokazu Tatsuoka, Wen Li, Erchao Meng, Daisuke Ishikwa, Kaito Nakane, Shingo Oda, Tomoji Matsushita, Natsuki Kurebayashi Apr 2014

Preparations Of Nanostructured Silicide Bundles And Oxide Arrays, Hirokazu Tatsuoka, Wen Li, Erchao Meng, Daisuke Ishikwa, Kaito Nakane, Shingo Oda, Tomoji Matsushita, Natsuki Kurebayashi

Makara Journal of Technology

A variety of nanostructured silicide bundles and oxide nanowire arrays with abundant, non-toxic materials we are prepared. The CrSi2 nanowire and Mg2Si/MgO composite nanowire bundles were synthesized using a Si substrate and a SiOx nanofiber bundle, respectively. The hexagonal MoSi2 nanosheet bundles were also synthesized using a MoS2 layered material as a template. In addition, ZnO, CuO/Cu2O and a-Fe2O3 nanowire arrays were prepared on semiconductor or metallic substrates. The growth phenomena and the structural properties of the nanostructured materials awere investigated. In addition, the preparations of axial and radial nanowire structures weare examined.


Bioethanol Production From Iles-Iles And Sorghum Starch As Raw Materials (Effect Of Cacl 2 Addition And Saccharification Time), Kusmiyati Kusmiyati, Ali Mahmudi Apr 2014

Bioethanol Production From Iles-Iles And Sorghum Starch As Raw Materials (Effect Of Cacl 2 Addition And Saccharification Time), Kusmiyati Kusmiyati, Ali Mahmudi

Makara Journal of Technology

Bioethanol produced from agricultural sources is one alternative energy that has been developed to substitute for petroleum. However, the use of food sources such as corn and cassava to produce bioethanol still face obstacles that lead to the scarcity of food and an increase in food prices. The aim of this study was to produce bioethanol from sorghum and iles-iles, which are not used by humans as food, especially in Indonesia. For both materials, the variables studied were saccharification time (4, 8, 24, and 48 h) and concentration of CaCl2 added to the liquefaction slurry (0, 100, 200, 300, and …


The Effect Of Zephyr Layer Orientation On Zephyrboard Made From Oil Palm Petiole, Lusita Wardani, Muhamad Yusram Massijaya, Yusuf Sudo Hadi, I Wayan Darmawan Apr 2014

The Effect Of Zephyr Layer Orientation On Zephyrboard Made From Oil Palm Petiole, Lusita Wardani, Muhamad Yusram Massijaya, Yusuf Sudo Hadi, I Wayan Darmawan

Makara Journal of Technology

It is very important to utilize oil palm petiole for the production of zephyr boards. This study aimed to analyze the effect of layer orientation on zephyr board quality. Zephyr boards were made with three coating patterns (A = cross perpendicular, B= combine A and C, and C= paralell) and five zephyr layers using urea formaldehyde adhesive. They were pressed for 20 min at a pressure of 25 kgf/cm² and a temperature 120 ºC, to a target density of 0.80 g/cm³ and a size of 300 mm X 300 mm X 12 mm. Our results showed that the physical and …


Performance Evaluation Of An Optimized Floating Breakwater In Oblique Waves With A Higher-Order Boundary Element Method, Faisal Mahmuddin, Masashi Kashiwagi Apr 2014

Performance Evaluation Of An Optimized Floating Breakwater In Oblique Waves With A Higher-Order Boundary Element Method, Faisal Mahmuddin, Masashi Kashiwagi

Makara Journal of Technology

In the previous study, the optimal performance of a two-dimensional (2D) floating breakwater shape was obtained. The performance of this shape was also confirmed with a model experiment in a towing tank. Moreover, the shape’s performance in three dimensions (3D) was investigated in a subsequent study. However, to predict the shape’s performance in a real application more accurately, the shape’s characteristics in oblique waves must also be evaluated. In this study, the performance and characteristics of the model (hydrodynamic forces, body motions, wave elevations, and drift forces) are computed using a higher-order boundary element method (HOBEM). The HOBEM, which is …


Microgrid Development Using A Grid Tie Inverter, Hartono Budi Santoso, Budiyanto Budiyanto Dec 2013

Microgrid Development Using A Grid Tie Inverter, Hartono Budi Santoso, Budiyanto Budiyanto

Makara Journal of Technology

The use of renewable energy sources (RES), especially photovoltaic (PV), to meet the demand of electrical energy has been getting a great deal of attention as an alternative solution to electrical energy deficit problems. RES are being applied in power systems in a variety of configurations including microgrid systems. One of the characteristics of a microgrid is capability to supplying power to grid when there is an excess power to supply local load. This research examines the chances of saving power consumption from grid using power converters grid tie inverter (GTI) in a microgrid configuration. The test is done by …


Surface Treatment Of Fly Ash For Improving The Tensile Strength Of Fly Ash/Unsaturated Polyester Composites, Sugiman Sugiman, Paryanto Dwi Setyawan Dec 2013

Surface Treatment Of Fly Ash For Improving The Tensile Strength Of Fly Ash/Unsaturated Polyester Composites, Sugiman Sugiman, Paryanto Dwi Setyawan

Makara Journal of Technology

The paper presents the surface treatment of fly ashes using acid and alkali solution on the tensile strength of the fly ash/unsaturated polyester (UP) composites. Sulfuric acid (H2SO4), hydrofluoric acid (HF) and sodium hydroxide (NaOH) solution with concentration of 0%, 5%, 10%, 15%, and 20% (by weight) were used for surface treatment of fly ashes. Generally, the tensile strength of the treated fly-ash/UP composites shows a significant increase compared to the untreated fly ash. Of all surface treatments studied, the optimum tensile strength was obtained at a concentration of 10%. At this concentration, at a fly ash content of 30% …


Recycling Roof Tile Waste Material For Wall Cover Tiles, Ambar Mulyono, Silfia Mona Aryani, Joko Lulut Dec 2013

Recycling Roof Tile Waste Material For Wall Cover Tiles, Ambar Mulyono, Silfia Mona Aryani, Joko Lulut

Makara Journal of Technology

Prior research on roof tile waste treatment has attempted to find the appropriate technology to reuse old roof tile waste by create wall cladding materials from it. Through exploration and experimentation, a treatment method has been discovered to transform the tile fragments into artificial stone that resembles the shape of coral. This baked clay artificial stone material is then processed as a decorative element for vertical surfaces that are not load-bearing, such as on the interior and exterior walls of a building. Before applying the fragments as wall tiles, several steps must be taken: 1) Blunting, which changes the look …


Synthesis Of Tungsten Oxide Nanowires Onto Ito Glass Using T-Cvd, Tomy Abuzairi, Bohr-Ran Huang, Tzu-Ching Lin Dec 2013

Synthesis Of Tungsten Oxide Nanowires Onto Ito Glass Using T-Cvd, Tomy Abuzairi, Bohr-Ran Huang, Tzu-Ching Lin

Makara Journal of Technology

Tungsten oxide is an n-type semiconductor with interesting physical and chemical properties that make it suitable for various technological applications. Tungsten oxide nanowires were synthesized not only at low temperature but also without the use of any catalysts. The tungsten oxide nanowires were synthesized at 550 °C with tungsten layers onto the ITO glass using thermal chemical vapor deposition (T-CVD). The SEM image shows that the tungsten oxide nanowires are effectively grown with the 200 nm tungsten film. The Raman spectra shoulder at ~690 cm-1 proves the synthesized of tungsten oxide nanowires.


Semiconductor Thermal Neutron Detector, Toru Aoki, Aki Miyake, Takayuki Nakano, Akifumi Koike, Hisashi Morii, Hidenori Mimura Dec 2013

Semiconductor Thermal Neutron Detector, Toru Aoki, Aki Miyake, Takayuki Nakano, Akifumi Koike, Hisashi Morii, Hidenori Mimura

Makara Journal of Technology

The CdTe and GaN detector with a Gd converter have been developed and investigated as a neutron detector for neutron imaging. The fabricated Gd/CdTe detector with the 25 mm thick Gd was designed on the basis of simulation results of thermal neutron detection efficiency and spatial resolution. The Gd/CdTe detector shows the detection of neutron capture gamma ray emission in the 155Gd(n, g)156Gd, 157Gd(n, g)158Gd and 113Cd(n, g)114Cd reactions and characteristic X-ray emissions due to conversion-electrons generated inside the Gd film. The observed efficient thermal neutron detection with the Gd/CdTe detector shows its promise in neutron radiography application. Moreover, a …


Radiation Characteristics Of A Planar Strip Dipole Antenna And A Slot Dipole Antenna For Thz Applications, Catur Apriono, Eko Tjipto Rahardjo Dec 2013

Radiation Characteristics Of A Planar Strip Dipole Antenna And A Slot Dipole Antenna For Thz Applications, Catur Apriono, Eko Tjipto Rahardjo

Makara Journal of Technology

The development of a THz system often requires a device that is used to radiate or detect THz waves. One way to fulfill this requirement is to use an antenna. Therefore, we need to consider the radiation characteristics of an antenna working in the THz region. In this paper, we present simulation study of two dipole antennas, i.e. a planar strip dipole antenna and a slot dipole antenna. The simulation results show that a planar strip dipole antenna has a better radiation efficiency (more than 95%) compared to the slot dipole. It also shows that an efficiency of more than …


The Effect Of Pressing Temperature And Time On The Quality Of Particle Board Made From Jatropha Fruit Hulls Treated In Acidic Condition, Apri Heri Iswanto, Fauzi Febrianto, Yusuf Sudo Hadi, Surdiding Ruhendi, Dede Hermawan Dec 2013

The Effect Of Pressing Temperature And Time On The Quality Of Particle Board Made From Jatropha Fruit Hulls Treated In Acidic Condition, Apri Heri Iswanto, Fauzi Febrianto, Yusuf Sudo Hadi, Surdiding Ruhendi, Dede Hermawan

Makara Journal of Technology

The high of pH of jatropha fruit hulls causes the negative properties of particleboard made from this material. Adjusting the particle acidity and pressing conditions (temperature and time) is among the technical modifications available to improve this particleboard’s properties. Particle acidity has been adjusted in a previous research project, and immersing the particles in acetic acid was found to be the best treatment in this preliminary research. In order to improve the particleboard’s properties, an experiment was conducted to determine the best pressing temperature and time. The objective of the research was to evaluate the influence of pressing temperature and …


Multi-Segment Multi-Criteria Approach For Selection Of Trenchless Construction Methods, Ashikul Islam Oct 2013

Multi-Segment Multi-Criteria Approach For Selection Of Trenchless Construction Methods, Ashikul Islam

Doctoral Dissertations

The research work presented in this thesis has two broad objectives as well as five individual goals. The first objective is to search and determine the minimum cost and corresponding goodness-of-fit by using a different combination of methods that are capable of resolving the problem that exists in multiple segments. This approach can account for variations in unit price and the cost of the design and the inspection associated with multiple methods. The second objective is to calculate the minimum risk for the preferred solution set. The five individual goals are 1) reduction in total cost, 2) application of Genetic …


The Effect Zeolite Addition In Natural Rubber Polypropylene Composite On Mechanical, Structure, And Thermal Characteristics, Nurdin Bukit, Erna Frida Aug 2013

The Effect Zeolite Addition In Natural Rubber Polypropylene Composite On Mechanical, Structure, And Thermal Characteristics, Nurdin Bukit, Erna Frida

Makara Journal of Technology

This study was conducted to determine the effect of zeolite as filler on mechanical properties, and thermal structure blends of natural rubber and polypropylene (NR/PP). In this study, NR/PP/PP-g-MA blends was filled uncalcined zeolite and calcined zeolite at different weight percent of the 2, 4, and 6%. Samples were characterized to determine the tensile strength, fracture elongation and Young's modulus. Structure of the samples was investigated using XRD method and thermal characteristics were analyzed using DTA/TGA technique. The results obtained for tensile strength showed a significant influence with the addition zeolite of the NR/PP blends at 2% by weight of …


Characteristics Of Vacuum Freeze Drying With Utilization Of Internal Cooling And Condenser Waste Heat For Sublimation, Muhammad Idrus Alhamid, Nasruddin Yusuf, Indra Teuku Meurah Mahlia, Engkos Ahmad Kosasih, Muhamad Yulianto, Rio Ricardi Aug 2013

Characteristics Of Vacuum Freeze Drying With Utilization Of Internal Cooling And Condenser Waste Heat For Sublimation, Muhammad Idrus Alhamid, Nasruddin Yusuf, Indra Teuku Meurah Mahlia, Engkos Ahmad Kosasih, Muhamad Yulianto, Rio Ricardi

Makara Journal of Technology

Vacuum freeze drying is an excellent drying method, but it is very energy-intensive because a relatively long drying time is required. This research investigates the utilization of condenser waste heat for sublimation as a way of accelerating the drying rate. In addition, it also investigates the effect of internal cooling combined with vacuum cooling in the pressure reduction process. Jelly fish tentacles were used as the specimen, with different configurations for condenser heat waste and internal cooling valve opening. The results show that heating with condenser heat waste can accelerate the drying rate up to 0.0035 kg/m2.s. In addition, pre-freezing …


A New Experimental Approach To Evaluate Plasma-Induced Damage In Microcantilever, Yuki Nishimori, Shinji Ueki, Masakazu Sugiyama, Seiji Samukawa, Gen Hashiguchi Aug 2013

A New Experimental Approach To Evaluate Plasma-Induced Damage In Microcantilever, Yuki Nishimori, Shinji Ueki, Masakazu Sugiyama, Seiji Samukawa, Gen Hashiguchi

Makara Journal of Technology

Plasma etching, during micro-fabrication processing is indispensable for fabricating MEMS structures. During the plasma processes, two major matters, charged ions and vacuum–ultraviolet (VUV) irradiation damage, take charge of reliability degradation. The charged ions induce unwanted sidewall etching, generally called as “notching”, which causes degradation in brittle strength. Furthermore, the VUV irradiation gives rise to crystal defects on the etching surface. To overcome the problem, neutral beam etching (NBE), which use neutral particles without the VUV irradiation, has been developed. In order to evaluate the effect of the NBE quantitatively, we measured the resonance property of a micro-cantilever before and after …