Open Access. Powered by Scholars. Published by Universities.®

Civil Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Materials Science and Engineering

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 481 - 510 of 735

Full-Text Articles in Civil Engineering

Coastal Physical Vulnerability Of Surabaya And Its Surrounding Area To Sea Level Rise, Sayidah Sulma, Eko Kusratmoko, Ratna Saraswati Nov 2012

Coastal Physical Vulnerability Of Surabaya And Its Surrounding Area To Sea Level Rise, Sayidah Sulma, Eko Kusratmoko, Ratna Saraswati

Makara Journal of Technology

The study for coastal vulnerability to sea level rise was carried out in Surabaya and its surrounding area, it has focused on calculations of the physical vulnerability index were used coastal vulnerability index (CVI) methods. It was standardized by the multi criteria analysis (MCA) approach according to the study area. The score of each physical variable derived from remote sensing satellite data and the results of studies that have been done, such as modeling results and thematic maps, and then integrated into geographic information systems (GIS). Result of this study shows that the coastal areas of Gresik, Surabaya, and Sidoarjo …


The Effect Of Size And Crumb Rubber Composition As A Filler With Compatibilizer Pp-G-Ma In Polypropylene Blends And Sir-20 Compound On Mechanical And Thermal Properties, Erna Frida Nov 2012

The Effect Of Size And Crumb Rubber Composition As A Filler With Compatibilizer Pp-G-Ma In Polypropylene Blends And Sir-20 Compound On Mechanical And Thermal Properties, Erna Frida

Makara Journal of Technology

Having been researched the development of thermoplastic elastomer material of polypropylene and natural rubber SIR- 20 compound with Crumb Rubber as the filler. Reinforced polypropylene with size 60 mesh with 1 mm, and the composition of the Crumb rubber (30, 40, and 50) wt%. Observed mechanical properties are tensile strength, fracture elongation, Young's modulus, tear strength and impact strength. Thermal properties are analyzed by DSC and DTA/TGA. It is acquired that for the size of 60 mesh crumb rubber tensile strength, fracture elongation, Young’s modulus, tear strength and impact strength are bigger than 1mm size. The addition of 60 mesh …


Development Of Local-Economic-Development Small And Medium Industries (Led-Sme) In East Java, Rachmad Hidayat, Sabarudin Akhmad Nov 2012

Development Of Local-Economic-Development Small And Medium Industries (Led-Sme) In East Java, Rachmad Hidayat, Sabarudin Akhmad

Makara Journal of Technology

This paper presents the effects of Indonesian government’s developmental efforts of assistance and training performed on the growth of LED-SME business units and business performance. Both parameters of the government’s assistance and training were used to analyze the impact to the growth and performance of business unit. To achieve a comprehensive result, samples acquired in this research were about 190 entrepreneurs and managers of LED-SME from East Java. Based on the parameters above, there are five hypotheses made to prove the relationship of the assistance and training to the growth and performance of business units. The structural equation modeling (SEM) …


Cdm Potential In Palm Solid Waste Cogeneration As An Alternative Energy In Aceh Province, Mahidin Mahidin, Izarul Machdar, Muhammad Faisal, Muhammad Nizar Nov 2012

Cdm Potential In Palm Solid Waste Cogeneration As An Alternative Energy In Aceh Province, Mahidin Mahidin, Izarul Machdar, Muhammad Faisal, Muhammad Nizar

Makara Journal of Technology

Empty Fruit Bunch (EFB) as a solid waste in Crude Palm Oil (CPO) industry does not utilized yet as an alternative energy source to generate electricity. It is well known that use of solid wate (biomass) as an energy source is part of the Clean Development Mechanism (CDM) scheme due to direct reduction of Green House Gases (GHGs) emission and provide a direct contribution to sustainable development. Utilization of EFB as a source of energy is very potential to be implemented in Aceh since this province has 25 CPO Mills at the moment which actively produce about 870,000 ton EFB …


Small Scale Experiment: Thermal Performance Comparison Between Fiber-Cement Roof And Photovoltaic Roof In Malang, Indonesia, Nurhamdoko Bonifacius, Sri Nastiti Nugrahani Ekasiwi Nov 2012

Small Scale Experiment: Thermal Performance Comparison Between Fiber-Cement Roof And Photovoltaic Roof In Malang, Indonesia, Nurhamdoko Bonifacius, Sri Nastiti Nugrahani Ekasiwi

Makara Journal of Technology

Irradiation on the surface of photovoltaic module heats up the photovoltaic module itself and the room underneath the roof of integrated photovoltaic building in the tropics area. Room heating reduces thermal condition and photovoltaic module surface heating reduces its performance in generating electricity. This paper discusses an experiment of measuring the surface temperature of photovoltaic modules and fiber-cement roof surface as a comparison. This experiment also measures the impact of rising temperatures in each space underneath. It used small-scale mock-ups exposed to direct sunlight. The result of the experiment shows that photovoltaic roof surface temperature is lower than fiber-cement roof …


Improved Optical Probe For Measuring Phytoplankton Suspension Concentrations Based On Optical Fluoresensce And Absorption, Retno Wigajatri Purnamaningsih, Nining Betawati Prihantini Nov 2012

Improved Optical Probe For Measuring Phytoplankton Suspension Concentrations Based On Optical Fluoresensce And Absorption, Retno Wigajatri Purnamaningsih, Nining Betawati Prihantini

Makara Journal of Technology

This paper discusses the results of improved optical probe that works according to optical fluorescence and absorption phenomena for measuring the phytoplankton suspension concentrations. Measurements are made on the Scenedesmus sp. culture. The laboratory test has shown that range of concentration from 104 up to around 1 x 106 cells/mL; fluorescence intensity at λ = 685 nm; and logarithmic of transmission intensity at λ = 405 nm are proportional to the cell concentration linear with proportional constant γ = 4 × 10-5 and β = –2 × 10-7 mL/cell respectively.


Mechanical And Thermal Properties Of Polypropylene Reinforced By Calcined And Uncalcined Zeolite, Nurdin Bukit Nov 2012

Mechanical And Thermal Properties Of Polypropylene Reinforced By Calcined And Uncalcined Zeolite, Nurdin Bukit

Makara Journal of Technology

This study was carried out to compare mechanical and thermal properties of polypropylene (PP) reinforced with uncalcined and calcined zeolites. The PP samples were reinforced with zeolites at various quantities of 2, 4, and 6 (wt %). The comparison of the two types of zeolite was based on mechanical properties, including tensile strength, elongation at break, and Young’s modulus, and thermal characteristics analyzed using DSC, and DTA/TGA technique. The results obtained clearly revealed that both zeolites were able to significantly increase tensile strength and Young’s modulus of the samples, with calcined zeolite was found to work better. Addition of calcined …


Benchmark For Country-Level Earthquake Strong-Motion Instrumentation Program, Widjojo Adi Prakoso, I Nyoman Sukanta Nov 2012

Benchmark For Country-Level Earthquake Strong-Motion Instrumentation Program, Widjojo Adi Prakoso, I Nyoman Sukanta

Makara Journal of Technology

An empirical study to develop benchmark models at country-level to assess the suggested number of earthquake strongmotion stations based on a framework encompassing geographic, demographic, and socio-economic parameters is reported. The models are to provide a working estimate of the required number of stations for improving the strongmotion instrumentation program of Indonesia. National earthquake strong-motion networks of New Zealand, Japan, Taiwan, Iran, Turkey, and Italy were used as the references. The parameter proposed is the number of stations in land area of 1,000 km2, and three models based on the exponential regression analysis are presented as functions of population density, …


Worst Case Of Relative Disturbance Gain Array For Uncertain Distillation System, Rudy Agustriyanto, Jie Zhang Nov 2012

Worst Case Of Relative Disturbance Gain Array For Uncertain Distillation System, Rudy Agustriyanto, Jie Zhang

Makara Journal of Technology

This article discusses the constrained nonlinear optimization formulation for calculating the worst case of lower and upper bounds of relative disturbance gain array (RDGA) for uncertain process models. The proposed approach seeks the minimum and maximum values of the relative disturbance gains subject to the constraints in which the process and disturbance gains are within their uncertainty ranges. RDGA ranges are useful for control structure determination and the related robustness, as they provide information regarding the sensitivity to gain uncertainties. The proposed method is demonstrated by ternary distillation column case study. Closed loop simulation results support the analysis based on …


Biodiesel Production From Waste Cooking Oil Using Hydrodinamic Cavitation, Muhammad Dani Supardan, Satriana Satriana, Mahlinda Mahlinda Nov 2012

Biodiesel Production From Waste Cooking Oil Using Hydrodinamic Cavitation, Muhammad Dani Supardan, Satriana Satriana, Mahlinda Mahlinda

Makara Journal of Technology

The aim of this research was to study biodiesel production from low cost feedstock of waste cooking oil (WCO) using hydrodynamic cavitation apparatus. A two-step processes esterification process and transesterification process using hydrodynamic cavitation for the production of biodiesel from WCO is presented. The first step is acid-catalyzed esterification process for reducing free fatty acid (FFA) content of WCO and followed by base-catalyzed transesterification process for converting WCO to biodiesel as the second step. The result of esterification process with methanol to oil molar ratio of 5 and temperature of 60 oC showed that the initial acid value of WCO …


Knowledge Dictionary For Information Extraction On The Arabic Text Data, Wahyu Syaifullah Jauharis Saputra, Agus Zainal Arifin, Anny Yuniarti Nov 2012

Knowledge Dictionary For Information Extraction On The Arabic Text Data, Wahyu Syaifullah Jauharis Saputra, Agus Zainal Arifin, Anny Yuniarti

Makara Journal of Technology

Information extraction is an early stage of a process of textual data analysis. Information extraction is required to get information from textual data that can be used for process analysis, such as classification and categorization. A textual data is strongly influenced by the language. Arabic is gaining a significant attention in many studies because Arabic language is very different from others, and in contrast to other languages, tools and research on the Arabic language is still lacking. The information extracted using the knowledge dictionary is a concept of expression. A knowledge dictionary is usually constructed manually by an expert and …


Biaxial Bending And Lateral-Torsional Instability Of Imperfect Frp I-Beams Including Effects Of Retrofitting, Jodi Marie Knorowski Oct 2012

Biaxial Bending And Lateral-Torsional Instability Of Imperfect Frp I-Beams Including Effects Of Retrofitting, Jodi Marie Knorowski

Civil & Environmental Engineering Theses & Dissertations

This thesis presents the outcome of a theoretical and experimental study of the behavior of Fiber Reinforced Polymer (FRP) I-beams susceptible to lateral-torsional instability or when subjected to biaxial bending. Laboratory experiments involved application of vertical and horizontal static loads to a 4 x 4 x ¼ in. I-beam with various lengths, and the resulting displacement, twist, and strain were recorded. In the vertical direction, the beam was loaded from different reference load heights with respect to the shear center of the beam. The governing biaxial flexure and torsion differential equations were modified to account for the presence of initial …


Effects Of Alternate Cementitious Materials On Compressive Strength And Environmental Impacts Of Cement Mix Designs., Mitchell R. Bush Jun 2012

Effects Of Alternate Cementitious Materials On Compressive Strength And Environmental Impacts Of Cement Mix Designs., Mitchell R. Bush

Materials Engineering

Specific proportions of Portland cement, fly ash, and blast furnace slag cement mixtures where chosen by a ternary phase diagram to be investigated. By experimental testing and company data history fly ash was limited to not exceed 30% and contribution of Portland cement must be over 50%. Ten chosen mix designs were batched by following ASTM C305-94 and cured for twenty-eight and forty-two days, the extended cure length allows the reaction of pozzolanic material with calcium hydroxide to complete. Compressive strength testing at forty-two days yielded low strength for mix designs with 20% or less Portland cement compared to our …


Investigating The Use Of Pozzolans In Portland Cement Concrete And Inorganic Polymer Mortar, Omar Abdelmalek Saleh May 2012

Investigating The Use Of Pozzolans In Portland Cement Concrete And Inorganic Polymer Mortar, Omar Abdelmalek Saleh

UNLV Theses, Dissertations, Professional Papers, and Capstones

The use of pozzolans offers promising signs for a change in the cement industry. Pozzolan in its natural and artificial forms can be used to improve cement properties or to synthesize new cement. This study investigates the use of pozzolans in portland cement concrete and inorganic polymer mortar (geopolymer mortar).

This thesis is divided into two phases. Phase 1 investigates the use of natural pozzolan as a partial replacement of portland cement in concrete. In this phase two types of class N pozzolan are used separately to develop concrete mixtures contain different percentages of class N pozzolan. Fresh concrete properties …


Corrosion Rate Of Carbon Steel For Flowline And Pipeline As Transmission Pipe In Natural Gas Production With Co2 Content, Andi Rustandi, Muhammad Adyutatama, Enriko Fadly, Norman Subekti Apr 2012

Corrosion Rate Of Carbon Steel For Flowline And Pipeline As Transmission Pipe In Natural Gas Production With Co2 Content, Andi Rustandi, Muhammad Adyutatama, Enriko Fadly, Norman Subekti

Makara Journal of Technology

The purpose of this research is to investigate the corrosion rate of carbon steel as flowline and pipeline in natural gas production with CO2 content. The influence of variety of conditions that represent the actual conditions in practice such as CO2 partial pressure and solution composition, particularly NaCl percentage were performed. Research conducted by polarization test and simulation methods using PREDICTTM software. The result of this research is used to illustrate the level of corrosion rate of typical carbon steel i.e. API 5L X-52 occurred in natural gas pipelines due to the effect of dissolved CO2. From the experiments obtained …


Concurrent Engineering Of Tolerance Synthesis And Process Selection For Products With Multiple Quality Characteristcs Considering Process Capability, Mohamad Imron Mustajib Apr 2012

Concurrent Engineering Of Tolerance Synthesis And Process Selection For Products With Multiple Quality Characteristcs Considering Process Capability, Mohamad Imron Mustajib

Makara Journal of Technology

The existences of variances that are very difficult to be removed from manufacturing processes provide significance of tolerance to the product quality characteristics target of customer functional requirement. Furthermore, quality loss incurred due to deviation of quality characteristics of the target with a specified tolerance. This article discusses the development of concurrent engineering optimization model of tolerance design and manufacturing process selection on product with multiple quality characteristics by minimizing total costs in the system, namely total manufacturing cost and quality loss cost as functions of tolerance, also rework and scrap costs. The considered multiple quality characteristics have interrelated tolerance …


Modification Of Flow Structure Over A Van Model By Suction Flow Control To Reduce Aerodynamics Drag, Harinaldi Harinaldi, Budiarso Budiarso, Warjito Warjito, Engkos Achmad Kosasih, Rustan Tarakka, Sabar Pangihutan Simanungkalit, I Gusti Made Fredy Lay Teryanto Apr 2012

Modification Of Flow Structure Over A Van Model By Suction Flow Control To Reduce Aerodynamics Drag, Harinaldi Harinaldi, Budiarso Budiarso, Warjito Warjito, Engkos Achmad Kosasih, Rustan Tarakka, Sabar Pangihutan Simanungkalit, I Gusti Made Fredy Lay Teryanto

Makara Journal of Technology

Automobile aerodynamic studies are typically undertaken to improve safety and increase fuel efficiency as well as to find new innovation in automobile technology to deal with the problem of energy crisis and global warming. Some car companies have the objective to develop control solutions that enable to reduce the aerodynamic drag of vehicle and significant modification progress is still possible by reducing the mass, rolling friction or aerodynamic drag. Some flow control method provides the possibility to modify the flow separation to reduce the development of the swirling structures around the vehicle. In this study, a family van is modeled …


Optimizing Fermentation Medium To Produce Cyclosporin A Using Response Surface Methodology, Rofiq Sunaryanto Apr 2012

Optimizing Fermentation Medium To Produce Cyclosporin A Using Response Surface Methodology, Rofiq Sunaryanto

Makara Journal of Technology

Response surface methodology (RSM) is a three factorial model which illustrates the relationship between one or more independent variables. RSM can be used to optimize the fermentation medium for the production of Cyclosporin A from the isolate Tolypocladium inflatum. The optimal point of the response surface area is predicted by using a seconddegree polynomial model and applying the statistic model obtained from the central composite design (CCD). The results of optimizing the fermentation medium for Cyclopsorin using the three independent variables of glucose, casein, and KH2PO4 show that all three of the independent variables affect the production of Cyclosporin A. …


Age, Gender, And Muscle Strength: A Study Based On Indonesian Samples, Henny Henny, Hardianto Iridiastadi, Iftikar Zahedi Sutalaksana Apr 2012

Age, Gender, And Muscle Strength: A Study Based On Indonesian Samples, Henny Henny, Hardianto Iridiastadi, Iftikar Zahedi Sutalaksana

Makara Journal of Technology

Age and gender have been commonly used as a main criterion in accepting a job aplicant, but it is usually not clear how these affect job performance. While a number of recent studies have been done that describe the relationships between age, gender, and participants capacity (e.g., muscle strength), the results have been inconclusive. In Indonesia, in particular, such issues have been rarely investigated, and it is still important to study the issue since the relationships between these factors are population-specific. This study aimed at describing the relationships between age and muscle strength among workers for both genders. Ninety-six male …


Circularly Polarized Microstrip Array Antenna For Ground Segment In Quasi-Zenith Satellite System, Fitri Yuli Zulkifli, Eko Tjipto Rahardjo Apr 2012

Circularly Polarized Microstrip Array Antenna For Ground Segment In Quasi-Zenith Satellite System, Fitri Yuli Zulkifli, Eko Tjipto Rahardjo

Makara Journal of Technology

In satellite communication system, antenna plays an important role. Therefore, the antenna must meet some requirements, such as high gain, circular polarization, and good directivity. In this paper, a four element linear array triangular patch microstrip antenna with cross slot is designed to be used for Quasi-Zenith satellite system. A simulation study as well as experimental study was carried out. The simulation showed that the 3 dB axial ratio bandwidth of 87 MHz (2.569-2.656 GHz) is achieved while the measured results showed 96 MHz (2.556-2.652 GHz). The linear array of 4 element antenna has a gain of 13.73 dB and …


Tolerance Limit For Trucks With Excess Load In Transport Regulation In Indonesia, Sigit Pranowo Hadiwardoyo, Raden Jachrizal Sumabrata, Mohammed Ali Berawi Apr 2012

Tolerance Limit For Trucks With Excess Load In Transport Regulation In Indonesia, Sigit Pranowo Hadiwardoyo, Raden Jachrizal Sumabrata, Mohammed Ali Berawi

Makara Journal of Technology

Reliability of a road is mandatory since damaged will impede the traffic. Destruction is caused by various factors; one of the most important factors is excess load. Overload may give the load of each axle of a vehicle exceeds the determined standard. This condition occurs in trucks exceeding the load limit. In designing the structure of a road based on the method of Directorate General of Highways Ministry of Public Works of the Republic of Indonesia, axle load calculated in equivalent-number, or known as equivalent axle load (EAL), of 8.16 tons of standard axle. Total equivalent-number over the service life …


Earthquake Damage Intensity Relationship For Residential Houses In West Sumatra, Febrin Anas Ismail, Abdul Hakam, Fauzan Fauzan Apr 2012

Earthquake Damage Intensity Relationship For Residential Houses In West Sumatra, Febrin Anas Ismail, Abdul Hakam, Fauzan Fauzan

Makara Journal of Technology

The Sumatra 30 September 2009 earthquake has damaged hundred thousand buildings in West Sumatra Province. The earthquake is located in 100 km offshore of Padang City, the Capital City of the province. Survey has been conducted to assess the damage of the building in few days after the earthquake. In this survey, the damage of buildings are categorised into 3 level that are heavily, moderate and slightly damages. This paper explores the level damage of building and then the intensity of the shaking in the affected area. Then based on the coordinate of every building location, the buildings are scattered …


Evaluation Of Universitas Indonesia’S Recharge Pond Performance And Potential Utilization For Raw Water Source, Nyoman Suwartha, Resky Agaslian Pramadin Apr 2012

Evaluation Of Universitas Indonesia’S Recharge Pond Performance And Potential Utilization For Raw Water Source, Nyoman Suwartha, Resky Agaslian Pramadin

Makara Journal of Technology

Evaluasi Kinerja Waduk Resapan UI dan Potensi Pemanfaatannya sebagai Sumber Air Baku. Waduk resapan Universitas Indonesia (UI) telah dibangun sejak 5 tahun yang lalu. Namun kegiatan monitoring dan evaluasinya sangat minim dilakukan. Tujuan dari studi ini adalah untuk mengetahui laju resapan, dan untuk mengevaluasi kondisi kuantitas dan kualitas air waduk resapan selama musim kemarau dan penghujan. Pengukuran kedalaman muka air, intensitas curah hujan dan penguapan dilakukan untuk menentukan ketersediaan air, laju resapan, dan imbangan air waduk. Sejumlah air permukaan diambil dari waduk resapan dan sungai di tiga titik sampling untuk mengetahui kondisi kualitas air eksisting. Hasil studi menunjukkan tidak ada …


Effect Of Methanol Induction And Incubation Time On Expression Of Human Erythropoietin In Methylotropic Yeast Pichia Pastoris, Adi Santoso, Neng Herawati, Yana Rubiana Apr 2012

Effect Of Methanol Induction And Incubation Time On Expression Of Human Erythropoietin In Methylotropic Yeast Pichia Pastoris, Adi Santoso, Neng Herawati, Yana Rubiana

Makara Journal of Technology

Erythropoietin (EPO) is a glycoprotein hormone consists of 165 amino acids and has molecular mass of 30,400 Daltons. The large quantities of these hormone required to satisfy clinical demand are currently met by recombinant expression in mammalian cell, namely chinese hamster ovary (CHO). Pichia pastoris has become popular yeast based protein production systems to substitute mammalian expression systems. P. pastoris is capable to use methanol as sole carbon and energy source. In this study, recombinant human EPO (rhEPO) protein obtained by expressing the hEPO gene in methylotropic yeast P. pastoris, strain X33. The present work was carried out to study …


Fuel Saving Strategy In Spark Ignition Engine Using Fuzzy Logic Engine Torque Control, Aris Triwiyatno, Sumardi Sumardi Apr 2012

Fuel Saving Strategy In Spark Ignition Engine Using Fuzzy Logic Engine Torque Control, Aris Triwiyatno, Sumardi Sumardi

Makara Journal of Technology

In the case of injection gasoline engine, or better known as spark ignition engines, an effort to improve engine performance as well as to reduce fuel consumption is a fairly complex problem. Generally, engine performance improvement efforts will lead to increase in fuel consumption. However, this problem can be solved by implementing engine torque control based on intelligent regulation such as the fuzzy logic inference system. In this study, fuzzy logic engine torque regulation is used to control the throttle position entered by the driver to achieve optimal engine torque. An engine torque vs. throttle position and engine speed mapping …


An Agri-Food Supply Chain Model To Enhance The Business Skills Of Small-Scale Farmers Using Corporate Social Responsibility, Wahyudi Sutopo, Muh. Hisjam, Yuniaristanto Yuniaristanto Apr 2012

An Agri-Food Supply Chain Model To Enhance The Business Skills Of Small-Scale Farmers Using Corporate Social Responsibility, Wahyudi Sutopo, Muh. Hisjam, Yuniaristanto Yuniaristanto

Makara Journal of Technology

In general, small-scale vegetable farmers experience problems in improving the safety and quality of vegetables for supplying high-class consumers in modern retailers. Farmer Group and/or Cooperative (FGC) should be able to assist its members to meet the relevant provisions of modern retail on product specifications, delivery terms, and internal business requirements. This study proposed an agri-food supply chain (ASC) model that involves the corporate social responsibility (CSR) activities to enhance the business skills of the FGC as supplier of modern retailer. Multi-objective optimization programming is developed to determine the amount and timing of supply, level of farmers training skills, quality …


Pineapple Liquid Waste As Nata De Pina Raw Material, Agus Sutanto Apr 2012

Pineapple Liquid Waste As Nata De Pina Raw Material, Agus Sutanto

Makara Journal of Technology

This research aims to study the quantity, quality, ecological and economic feasibility of nata de pina production (NP) from pineapple liquid waste (PLW). The design of the study employs complete random design (CRD) with three treatments: PLW without nutrients addition (A), PLW nutrients addition (B), and PLW stored for six months with nutrients addition (C). The nata de pina’s production factors measured were weight, thickness, fiber content, color, brightness, and residual waste. The highest weight was reached in treatment B (899 grams), followed by treatment A (616.4 grams), and C (477.8 grams). The thickness of NP of the height and …


Modeling Of A New Structure Of Precision Air Conditioning System Using Secondary Condenser For Rh Regulation, Aries Subiantoro, Nasruddin Nasruddin, Feri Yusivar, Muhammad Idrus Al-Hamid, Bagio Budiardjo Apr 2012

Modeling Of A New Structure Of Precision Air Conditioning System Using Secondary Condenser For Rh Regulation, Aries Subiantoro, Nasruddin Nasruddin, Feri Yusivar, Muhammad Idrus Al-Hamid, Bagio Budiardjo

Makara Journal of Technology

A dynamic mathematical model for a new structure of precision air conditioning (PAC) has been developed. The proposed PAC uses an additional secondary condenser for relative humidity regulation compared to a basic refrigeration system. The work mechanism for this system and a vapour-compression cycle process of the system are illustrated using psychrometric chart and pressure-enthalpy diagram. A non-linear system model is derived based on the conservation of mass and energy balance principles and then linearized at steady state operating point for developing a 8th-order state space model suited for multivariable controller design. The quality of linearized model is analyzed in …


The Quantification Of The Fly Ash Adsorption Capacity For The Purpose Of Characterization And Use In Concrete, Zeyad Tareq Ahmed Jan 2012

The Quantification Of The Fly Ash Adsorption Capacity For The Purpose Of Characterization And Use In Concrete, Zeyad Tareq Ahmed

Dissertations, Master's Theses and Master's Reports - Open

Fly ash has been shown to be an effective replacement for portland cement in concrete mixtures. However, many fly ash materials contain unburned carbon from the combustion process. Unburned carbon in fly ash adsorbs air entraining admixtures (AEAs) reducing their effectiveness in providing a specified air void system in concrete materials. Measurement tools and methods for characterization of the adsorption properties of fly ash materials are necessary for beneficial use of fly ash materials in concrete. In this research, two methods were developed to measure and quantify the adsorption capacity AEAs on fly ash materials. The first method is the …


Corrosion Evaluation And Durability Estimation Of Aluminized Steel Drainage Pipes, Mersedeh Akhoondan Jan 2012

Corrosion Evaluation And Durability Estimation Of Aluminized Steel Drainage Pipes, Mersedeh Akhoondan

USF Tampa Graduate Theses and Dissertations

Aluminized steel pipes are expected to have a long service life, e.g. 75 years. Spiral ribbed aluminized pipes (SRAP) have been widely specified and used by the Florida Department of Transportation (FDOT) for drainage of runoff water. Confidence in the long term durability of SRAP has been challenged by recent unexpected early corrosion failures in various Florida locations. SRAP premature corrosion incidents have occurred in two modalities. Mode A has taken place in near-neutral soil environments and has often been associated with either gross manufacturing defects (i.e. helical cuts) or corrosion concentration at or near the ribs. Mode B took …