Mechanical Engineering Commons^™

The Effect Of Ca Content On Cao-Zeolite On Nitrogen Adsorption Capacity, Mohammad Nasikin, Tania Surya Utami, Agustina Tp Siahaan

Makara Journal of Technology

In industry, Ca zeolite is used as nitrogen selective adsorbent with the use of PSA (Pressure Swing Adsorption)/VSA (Vacuum Swing Adsorption) methods. Natural zeolite modified to be Cao-zeolite by ion exchange process using Ca(OH)2. Adsorption test was done on CaO-zeolite with different Ca concentration to understand how it’s adsorption phenomena on oxygen and nitrogen. Adsorption test has been done for CaO-zeolite with Ca concentration = 0,682%, 0,849% and 1,244% to oxygen and nitrogen with equal concentration seperately. Pressure variation has being done three times (5 minutes long each time) adsorption time to analyze the connection between adsorption time and how …

Cetane Number Booster Additive For Diesel Fuel Synthesized From Coconut Oil, Mohammad Nasikin, Rita Arbianti, Abdul Azis

Makara Journal of Technology

To reduce NOx, SOx, HC, and particulates that produce because of using diesel fuel, can be done by increasing cetane number. One of methods is adding an additive to diesel fuel. 2-Ethyl Hexyl Nitrate (2-EHN) is a commercial additive that an organic nitrate. Making an additive in this research is used palm oil by nitration reaction that used HNO3 and H2SO4. Result of this reaction is methyl ester nitrate that has a structure looks like 2-EHN. IR spectra from research show that methyl ester nitrate is indicated by spectrum NO2 at 1635 cm-1. This result show that methyl ester nitrate …

Analogy Method Development For Cost Estimation Of Software Design, Riyanarto Sarno, Joko Lianto Buliali, Siti Maimunah

Makara Journal of Technology

The important aspect of planning and managing software development project is to estimate the cost of a project. There are several methods for estimating the cost of a software development project, and the Analogy method is a method which gives relatively better estimates. This paper shows that the modified Analogy method selects a closer project reference, estimates more accurate project effort and cost. This study enhances the cost estimate technique by including valid and complete cost parameters, therefore the estimate of a project cost is better than the result of the standard Analogy method.

The Role Of Si3n4 Amorphous Phase In Nc-Tin/A-Si3n4 Nanocomposites In Increases The Hardness And Thermal Stability, Keba Moto

Makara Journal of Technology

The role of Si3N4 amorphous phase in nc-TiN/a-Si3N4 nanocomposites will be shown and compared with polycrystalline ZrN/Ni which has no such amorphous phase (non-composites). The presence of amorphous phase Si3N4 increases the hardness of film as well as the toughness of the bulk nanocomposites under indentation load. It has been observed that nc-TiN/a-Si3N4 nanocomposites films has higher thermal stability than ZrN/Ni polycrystalline films.

Biodiesel's Characteristics Preparation From Palm Oil, Tilani Hamid. S, Rachman Yusuf

Makara Journal of Technology

Biodiesel’s characteristics preparation from palm oil. Using vegetable oils directly as an alternative diesel fuel has presented engine problems. The problems have been attributed to high viscosity of vegetable oil that causes the poor atomization of fuel in the injector system and pruduces uncomplete combustion. Therefore, it is necessary to convert the vegetable oil into ester (metil ester) by tranesterification process to decrease its viscosity. In this research has made biodiesel by reaction of palm oil and methanol using lye (NaOH) as catalyst with operation conditions: constant temperature at 60 oC in atmosferic pressure, palm oil : methanol volume ratio …

Development Of Hardness Measurement Procedure For Nanocomposite Nc-Tin/A-Si3n4, Keba Moto

Makara Journal of Technology

Hardness of nc-TiN/a-Si3N4 nanocomposites which was determined by using two methods of measurements i. e. depth sensing method and remaining plastic indentation area that were magnified by using SEM (Scanning Electron Microscope) lie in the good agreement. The hardness value is not influenced by the biaxial and residual compressive stress. The measurement of the biaxial stress on the substrate shows a very small value of biaxial stress as well as the constant hardness and crystallite size against annealing temperature. Therefore, the reported hardness value here is the intrinsic value that depend on its microstructure properties.

Measured And Simulated Cooling Performance Comparison; Insulated Concrete Form Versus Frame Construction, Florida Solar Energy Center, Dave Chasar

FSEC Energy Research Center®

Four occupied homes near Dallas, Texas were monitored to compare cooling energy use. Two homes were built with typical wood frame construction, the other two with insulated concrete form (ICF) construction. Remote data loggers collected hourly readings of indoor and outdoor temperature, relative humidity, furnace runtime fraction, total building electrical energy and HVAC energy use. Data was recorded from January through August 2000.

Analysis of the measured data shows that insulated concrete form (ICF) construction can reduce seasonal cooling energy use 17 - 19% over frame construction in two-story homes in the North Texas climate. This result includes adjustments to …

Comparative Evaluation Of The Impact Of Roofing Systems On Residential Cooling Energy Demand In Florida, Florida Solar Energy Center, John Sherwin

FSEC Energy Research Center®

Roof and attic thermal performance exert a powerful influence on cooling energy use in Florida homes. The Florida Power and Light Company and the Florida Solar Energy Center instrumented six side-by-side Habitat homes in Ft. Myers, Florida with identical floor plans and orientation, R-19 ceiling insulation, but with different roofing systems designed to reduce attic heat gain. A seventh house had an unvented attic with insulation on the underside of the roof deck rather than the ceiling: (RGS) Standard dark shingles (control home); (RWB) White "Barrel" S-tile roof; (RWS) Light colored shingles; (RWF) White flat tile roof; (RTB) Terra cotta …

Correlation Between The Xps Peak Shapes Of Y1bu2cu3o7-X And Film Quality, Paul N. Barnes, Sharmila M. Mukhopadhyay, Timothy J. Haugan, Swaminathan Krishnaswami, Justin C. Tolliver, Iman Maartense

Mechanical and Materials Engineering Faculty Publications

X-ray photoelectron spectroscopy (XPS) depth profiling was used to investigate the compositional and chemical profile of a typical YBCO coated conductor architecture. Results of the process revealed that the Y(3d) photoelectronic peak shape in these films is very different from bulk YBCO. To investigate this, several samples of Y i Ba2Cu307_„ thin films were intentionally created of varying quality. The films were deposited on LaA10 3 by pulsed laser deposition with ./c. values ranging from poorly conducting up to several MA/cm2. Initial results indicated a potential correlation between the Y(3d) XPS peak shape (full-width-half-maximum) of the YBCO and the film …

A Fundamental Model Of Cyclic Instabilities In Thermal Barrier Systems, Anette M. Karlsson, J. W. Hutchinson, A. G. Evans

Mechanical Engineering Faculty Publications

Cyclic morphological instabilities in the thermally grown oxide (TGO) represent a source of failure in some thermal barrier systems. Observations and simulations have indicated that several factors interact to cause these instabilities to propagate: (i) thermal cycling; (ii) thermal expansion misfit; (iii) oxidation strain; (iv) yielding in the TGO and the bond coat; and (v) initial geometric imperfections. This study explores a fundamental understanding of the propagation phenomenon by devising a spherically symmetric model that can be solved analytically. The applicability of this model is addressed through comparison with simulations conducted for representative geometric imperfections and by analogy with the …

Viewpoint: Experimental Recovery Of Geometrically Necessary Dislocation Density In Polycrystals, Brent L. Adams, Bassem S. El-Dasher, Anthony D. Rollett

Faculty Publications

The authors wish to thank The Alcoa Technical Research Center for supplying the specimens and performing the compression tests. This work was supported primarily by the MRSEC program of the National Science Foundation under DMR-0079996. Application of electron backscattering diffraction methods to recover estimates of the geometrically necessary dislocation density is described. The limitations of the method arising from the opacity of crystalline materials and the spatial and angular resolution limits are discussed.

Experimental Demonstration Of Multiple Robot Cooperative Target Intercept, Timothy W. Mclain, Randal W. Beard, Jed M. Kelsey

Faculty Publications

This paper presents experimental results for the simultaneous intercept of preassigned targets by a team of mobile robots. The robots are programmed to mimic the dynamic behavior of unmanned air vehicles in constant-altitude flight. In proceeding to their targets, robots must avoid both known static threats and pop-up threats. An overview of the cooperative control strategy followed is given, as well as a description of the robot hardware and software used. Experimental results demonstrating simultaneous intercept of targets by the robot team are presented.

Fuel Consumption Modeling Of A Transport Category Aircraft: A Flight Operations Quality Assurance (Foqa) Analysis, Alan J. Stolzer

All-Inclusive List of Electronic Theses and Dissertations

Fuel is a very large operating cost category for major air carriers - second only to labor costs. Many air carriers have implemented extensive programs to monitor fuel usage. One of several emerging quality assurance programs in the aviation industry, Flight Operations Quality Assurance (FOQA) involves the routine collection and analysis of flight performance data recorded on the airplane for the purpose of improving s~fety and operational procedures. FOQA systems are not constrained by the same data limitations as are traditional aircraft performance monitoring programs and, thus, FOQA may serve as a robust new aircraft performance monitoring tool. The purpose …

Correlation And Prediction Of Fatigue Crack Growth Rate For Different R-Ratios, Sudip Dinda

Masters Theses

The prediction of fatigue crack growth rate of a structural material is an important aspect by which we can predict the critical or safe crack length and, therefore, avoid the sudden failure of components and structures.

There are numerous models which claim to predict the fatigue crack growth rate, but with the exception of the highly published "crack closure methodology" no other model lived up to the expectation of correlating the fatigue crack growth data or predicting the fatigue crack growth rate for different R-ratios.

In order to find an effective solution to the above problem a study has been …

Modeling And Simulation Of The Chemical Etching Process In Niobium Cavities, Qin Xue

UNLV Theses, Dissertations, Professional Papers, and Capstones

Niobium Cavities are important parts of the integrated NC/SC high-power linear accelerator (linac) that can accelerate over 100 mA of protons to several GeV. Surface finish of the niobium cavity plays an important role of achieving the best performance of niobium cavity. The chemical etching techniques have been widely used.

Chemical etching of the inner surface of the cavity is achieved by circulating acid through it. The acid interacts with the surface and eliminates imperfections. During the etching process, a pipe with baffles is inserted within the cavity to direct the flow along the surfaces.

A 2-D, axisymmetric, steady state, …

Design And Analysis For Melt Casting Metallic Fuel Pins Incorporating Volatile Actinides, Xiaolong Wu

UNLV Theses, Dissertations, Professional Papers, and Capstones

Fundamental issues related to the selection of a metallic fuel casting furnace design are presented and discussed including heating mechanisms, casting issues, crucible design, and issues related to the mass transport of americium. The process of evaluating all of these different criteria is undertaken to select a concept that would have the greatest chance of success for casting americium in a metallic fuel rod. Based on this evaluation process, a concept for the casting of metallic fuel pins containing high vapor pressure materials is selected and discussed. The important physics of this concept include mass transport of americium from the …

Developing A Sensing System For The Measurement Of Oxygen Concentration In Liquid Pb-Bi Eutectic: Quarterly Progress Report (May 01 – July 31, 2002), Yingtao Jiang, Bingmei Fu, Woosoon Yim

Transmutation Sciences Materials (TRP)

Accurate measurement of the oxygen concentration in liquid Lead-Bismuth Eutectic (LBE) cooling system is critical in the active control of the corrosion at the interface between LBE and the stainless steel of transport tubes. Currently, LANL (Los Alamos National Laboratory) scientists have employed an automobile-style YSZ (Yttria Stabilized Zirconia) oxygen sensor unit to measure oxygen levels in an engineeringscaled LBE test system. Although the theoretical model for calculating oxygen concentration based on voltage measurement of YSZ sensor in static conditions is well understood, there is an urgent and strong need to obtain a complete set of calibration curves for YSZ …

Design And Construction Of Interior Duct Systems, Florida Solar Energy Center, Janet Mcilvaine

FSEC Energy Research Center®

To combat the energy, durability, and indoor air quality penalties of duct leakage, energy experts have recommended putting the duct system and air handler inside the conditioned space. Two paths of accomplishing this have emerged: unvented attics/crawl spaces and interior chases. This study focuses on the design, construction, and performance of the interior chase approach as implemented by five different builders in Texas, North Carolina, and Florida.

Researchers found that, in many cases, breeches of the air barrier were evident from simple visual inspection. Critical points of design and construction were identified and will be presented through photos, design and …

Strength And Modulus Degradation Of Carbon Fiber-Reinforced Polymer Laminates From Fiber Misalignment, Xinbao Yang, Antonio Nanni, Stephen B. Haug, Chung Leung Sun

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Fiber-reinforced polymer (FRP) laminates are being used as external reinforcement for strengthening concrete members. The performance of unidirectional FRP laminates is highly dependent on fiber orientation with respect to applied load direction. In the case of fabrication by manual layup, it is possible to have fiber plies installed with improper orientation. In this project, the degradation of strength and modulus of carbon FRP laminates from fiber misalignment was investigated experimentally using tensile coupons. The specimens consisted of one and two plies of unidirectional carbon FRP impregnated with a two-component epoxy. The misalignment angles varied from 0 to 40° for the …

Investigation Of Port Fuel Injector Spray Mass Distribution By Laser Induced Fluorescence, Tuba Bayraktar

Mechanical & Aerospace Engineering Theses & Dissertations

Modern internal combustion engines have stringent requirements for performance and reduced toxic emissions. The fuel delivery system, and particularly the fuel injectors, have a vital role in reducing unburned hydrocarbons (HC) and carbon monoxide (CO) in exhaust emission.

The main goal of this study is to map the spatial and temporal distribution of the spray from a low-pressure gasoline fuel injector. To attain this goal, three tasks were performed: (1) the experimental investigation of the spray oscillation as functions of operating pressure and injector timing, (2) the determination of the appropriate dye/fuel combinations for one particular experimental technique, and (3) …

A Conceptual Design Tool For Engineers: An Amalgamation Of Theory Of Constraints, Theory Of Inventive Problem Solving And Logic, Stephen R. Luke

Mechanical & Aerospace Engineering Theses & Dissertations

This research creates a design methodology by synthesizing three different design tools, the Theory of Inventive Problem Solving (TRIZ), the Theory of Constraints (TOC) and Logic. The basic approach of this design method is to: (1) Reduce a design problem to a logic diagram, (2) Code the inputs and outputs to determine desirability and degree of control, (3) Identify the best inputs to manipulate in order to obtain the desired outputs and (4) Exploit innovative algorithms developed in TRIZ to find the best ways to manipulate the chosen inputs.

This research integrates and expands the methods of TRIZ and TOC. …

Investigation Of Forces Acting On Plain Discs, S. M. Mpanduji

Tanzania Journal of Engineering and Technology (TJET)

An investigation was carried out to study the mutually perpendicular forces generated by rotating and non-rotating plain discs similar to those used in disc ploughs. Experiments were conducted in a soil bin containing sand loam soil (Ryton sand) where forces were measured while changing disc rake and sweep angles. The results showed that draught forces were higher for non-rotating discs, while vertical and lateral forces were lower compared to rotating discs. Rotating discs were found to be suitable for counteracting high side forces because of less draught and higher lateral forces. The recommended optimum angles are between 8°–12° for disc …

Analysis On Possible Solution To Decreasing The Effect Of Non-Uniform Air-Gaps Due To Rotor Eccentricity In Asynchronous Machines, Dominic Chambega

Tanzania Journal of Engineering and Technology (TJET)

Rotor eccentricity introduces non-uniformity of the airgap which in turn causes additional frictional torques and losses in addition to establishing a uni-directional pulling magnetic force which is disastrous to the machine. This paper analyses the extent of the damage to the machine due to non-uniformity of the air-gap and proposes increasing the number of poles as a possible solution to arrest the effect. It is found through the analysis that as the number of poles increases the effect of eccentricity decreases.

Comparison Of Repair Costs Of Two Wheel Drive Tractors Under Tanzania Conditions, S. M. Mpanduji

Tanzania Journal of Engineering and Technology (TJET)

The repair costs of 2WD tractors were investigated in order to provide important information, which lacks in the scope of agricultural mechanization in Tanzania. Previously repair cost functions established for tractors in developed countries were used for both theoretical and practical purposes. The findings of this study have revealed that repair costs of tractors vary substantially from one make to another. The prediction functions developed in this study indicated that the magnitudes of repair costs in Tanzania are higher than the repair costs established in Europe and North America. The reason for this could be either due to high cost …

Solar Oven Development And Testing Contract Final Report, Florida Solar Energy Center, Philip W. Fairey

FSEC Energy Research Center®

The Florida Solar Energy Center (FSEC) was contracted by the Dorothy Ann Foundation (and its agent and representative, Darwin O. Curtis), to conduct an investigative study into the development of a state-of-the art solar cooker. A major goal of the contract was to investigate the potential means of improving the performance and long-term durability of the existing Cookit solar cooker.

Many of the activities and accomplishments conducted as part of this contract have been provided in the reports and analyses previously sent to the contact representative. The purpose of this final report is to list the various task accomplishments defined …

Solar Thermal Billing Program In Florida, Florida Solar Energy Center, Carlos Colon

FSEC Energy Research Center®

This paper presents the development, implementation, and results of Lakeland Electric's solar thermal billing program in Florida. The three-phase solar program was started in 1997 with funds from the Florida Energy Office (FEO) and the technical assistance of the Florida Solar Energy Center (FSEC). It was designed as a model to expand the concept of distributed energy generation, and to augment the use of solar domestic hot water (SDHW) systems. The solar thermal billing program relies on the proceeds generated from the sale of hot water energy. Twenty-nine SDHW systems, which are owned by Lakeland Electric (LE), gradually began operation …

Autonomous Hierarchical Control Of Multiple Unmanned Combat Air Vehicles (Ucavs), Timothy Mclain, Randal W. Beard, Sai-Ming Li, Jovan D. Boskovic, Sanjeev Seereeram, Ravi Prasanth, Jayesh Amin, Raman K. Mehra

Faculty Publications

In this paper we present a hierarchical control scheme that enables multiple UCAVs to achieve demanding missions in hostile environments autonomously. The objective is to use a swarm of UCAVs for a SEAD type mission: fly the UCAVs in a formation to an enemy territory populated with different kinds of threats, collect enemy information or destroy certain targets, and return to the base, all without human intervention. The scheme is an integration of four distinct components, including: (1) high level Voronoi diagram based path planner to avoid static threats; (2) low level path planner to avoid popup threats; (3) differential …

An Interactive Visual Environment For Scientific Problem Solving, Georg F. Mauer

Mechanical Engineering Faculty Research

Science and engineering students do not typically receive explicit training in scientific problem solving, i.e. applying science principles to specific situations. Students’ problem solving skills often show little improvement throughout their course of studies. This paper describes a structured, graphical, interactive (GUI) learning environment, which presents problems and tools for analysis in systematic and logical order, and encourages the student to develop the solution path in the manner of an experienced expert. The learning environment’s subject area is Engineering Dynamics, which was selected for its systematic structure and its early (usually sophomore) place in the undergraduate curriculum. The software presents …

Alternative Ways To Teaching Hvac And Related Subjects Through Actual Project Involvement-Three Case Studies, Samir F. Moujaes

Mechanical Engineering Faculty Research

No abstract provided.

Development Of A Model For Induction Heating, Randy Clarksean, Yitung Chen

Fuels Campaign (TRP)

There are two coupled equations that must be solved in order to determine the power deposition. The numerical solution of these equations is needed in order to apply a source term within the energy equations. These equations have previously solved in FIDAP. That implementation used modified versions of the momentum and energy equations to provide a mechanism for the solution of two coupled equations. Currently, we want to solve for the induction heating field in addition to the flow field and the energy equation. In order to do this, a mechanism has to be defined within FIDAP to solve these …