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Articles 211 - 240 of 317

Full-Text Articles in Operations Research, Systems Engineering and Industrial Engineering

Timetable Management Technique In Railway Capacity Analysis: Development Of The Hybrid Optimization Of Train Schedules (Hots) Model, Hamed Pouryousef Jan 2015

Timetable Management Technique In Railway Capacity Analysis: Development Of The Hybrid Optimization Of Train Schedules (Hots) Model, Hamed Pouryousef

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

There are two general approaches to improve the capacity in a rail corridor, either by applying new capital infrastructure investment or by improving the operation of the rail services. Techniques to evaluate the railway operation include modeling and optimization through the use of commercial timetable management and rail simulation tools. However, only a few of the existing tools include complete features of timetable management techniques (e.g. timetable compression) are equipped with an optimization model for rescheduling and timetable improvement and this is especially true when it comes to the U.S. rail environment that prevalently uses unstructured operation practices.

This dissertation …


Wind Farm Optimization Using Evolutionary Algorithms, Carlos Marco Ituarte-Villarreal Jan 2015

Wind Farm Optimization Using Evolutionary Algorithms, Carlos Marco Ituarte-Villarreal

Open Access Theses & Dissertations

In recent years, the wind power industry has focused its efforts on solving the Wind Farm Layout Optimization (WFLO) problem. Wind resource assessment is a pivotal step in optimizing the wind-farm design and siting and, in determining whether a project is economically feasible or not. In the present work, three (3) different optimization methods are proposed for the solution of the WFLO: (i) A modified Viral System Algorithm applied to the optimization of the proper location of the components in a wind-farm to maximize the energy output given a stated wind environment of the site. The optimization problem is formulated …


Color Removal From Pulp Mill Effluent Using Coal Ash Produced From Georgia Power Coal Combustion Plants, Christopher B. Willett Jan 2015

Color Removal From Pulp Mill Effluent Using Coal Ash Produced From Georgia Power Coal Combustion Plants, Christopher B. Willett

College of Graduate Studies: Theses & Dissertations

Two environmental concerns currently face Georgia: coal fly ash (CFA) waste from coal power plants, and the effluent generated by pulp mills. Pulp mill effluent discolors surface waters into which it is discharged, and has been proven to negatively impact the dissolved oxygen and carbon necessary for aquatic life. The proposed solution is a cost-effective adsorption treatment using an inexpensive but abundantly available waste material: CFA. CFA possesses beneficial properties that allow it to effectively remove contaminants, and is available at significantly reduced cost. The primary research objective was to define treatment parameters that would result in the maximum removal …


The Engagement Of Expert Opinions In The Modeling Of Multi-Attribute Decision Making For The Selection Of Project Delivery Methods In Building Construction, Issam H. Algraiw Jan 2015

The Engagement Of Expert Opinions In The Modeling Of Multi-Attribute Decision Making For The Selection Of Project Delivery Methods In Building Construction, Issam H. Algraiw

Doctoral Dissertations

"Choosing the most appropriate project delivery method (PDM) available is acknowledged as a crucial issue in the construction industry. Both the choice and application of an unsuitable PDM can result in project failure. Likewise, the selection of a suitable PDM can increase the chance for project success. A method of selecting from among the seven PDMs recognized by the Construction Specifications Institute (CSI) was created in an attempt to address this issue.

This research was comprised of three objectives. The first objective was to determine the influential factors needed to select the appropriate PDMs available to the US construction industry. …


Influence Of Spatial Variations Of Railroad Track Stiffness And Material Inclusions On Fatigue Life, Celestin Nkundineza Jan 2015

Influence Of Spatial Variations Of Railroad Track Stiffness And Material Inclusions On Fatigue Life, Celestin Nkundineza

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Railroad transportation is very important for economic growth and effective maintenance is one critical factor for its economic sustainability. The high repetitive forces from a moving railcar induce cyclic stresses that lead to rail bending and potential deterioration due to fatigue crack initiation and propagation. Previous research for prediction of fatigue life has been done under the assumptions of a uniform track bed and a homogeneous rail. However the spatial variation of the track stiffness is expected to increase the maximum stresses in the rail and, therefore, accelerate the fatigue process. The research described in this dissertation is focused on …


Assessment Of Quality Stability Of Composite Flours Produced By Dar Es Salaam Smes, Leonard Rweyemamu Dec 2014

Assessment Of Quality Stability Of Composite Flours Produced By Dar Es Salaam Smes, Leonard Rweyemamu

Tanzania Journal of Engineering and Technology (TJET)

A study was conducted to assess quality stability of cereal flours processed by food processing SMEs in Dar es Salaam. This product is obtained by mixing various cereal grains and is considered as of higher nutritional values in Tanzania. The shelf-life was predicted by determining water activity (aw) and moisture content (MC) levels and plotting the water sorption isotherms (MSI). Ninety per cent of investigated samples (N=78) were found packaged in the materials of various quality conditions. It was found that the packaging materials mostly used is plastic films (63%), paper packets/bags (26%), hard papers (3%), plastic jars (1%) and …


Properties Of Boards Made From Rice Husk And Portland Cement As Binders And Reinforced With Sisal Fibres, Alex Mrema Dec 2014

Properties Of Boards Made From Rice Husk And Portland Cement As Binders And Reinforced With Sisal Fibres, Alex Mrema

Tanzania Journal of Engineering and Technology (TJET)

A research study demonstrated that rice husks can be used to manufacture boards which can be used in low cost housing if bound by Portland limestone cement (CEM II/A-L/ 32.5R) and reinforced with sisal fibers to cater for their brittle behavior and that such boards can provide a substitute for wood panels. Boards made of rice husks and cement in the ratios of 1/3.3, 1/ 3.6 and 1/4 and with sisal fiber reinforcement contents of 0%, 0.4%, 0.5% and 0.8% were prepared and tested for their physical and mechanical properties. The results were compared with standard requirements for boards made …


Modeling Sustainability In Renewable Energy Supply Chain Systems, Fei Xie Dec 2014

Modeling Sustainability In Renewable Energy Supply Chain Systems, Fei Xie

All Dissertations

This dissertation aims at modeling sustainability of renewable fuel supply chain systems against emerging challenges. In particular, the dissertation focuses on the biofuel supply chain system design, and manages to develop advanced modeling framework and corresponding solution methods in tackling challenges in sustaining biofuel supply chain systems. These challenges include: (1) to integrate 'environmental thinking' into the long-term biofuel supply chain planning; (2) to adopt multimodal transportation to mitigate seasonality in biofuel supply chain operations; (3) to provide strategies in hedging against uncertainty from conversion technology; and (4) to develop methodologies in long-term sequential planning of the biofuel supply chain …


A Strategic Approach To Effectively Manage Supplier Quality Within The Construction Industry, Rufaidah Almaian Dec 2014

A Strategic Approach To Effectively Manage Supplier Quality Within The Construction Industry, Rufaidah Almaian

Graduate Theses and Dissertations

The aim of the research is to determine the best practices for supplier quality management (SQM) in the construction industry that ensure that the supplied materials and equipment for construction projects are within the quality requirements. The research is based on three main objectives. The first objective is to describe and assess the process of assuring supplier quality inside and outside the construction industry. The second objective is to develop a framework for the supplier quality process based on the collection of SQM practices from multiple data sources. The third objective is to assess the SQM practices within the developed …


Methane Production By A Packed-Bed Anaerobic Digester Fed Dairy Barn Flush Water, Sean Richard Thomson Dec 2014

Methane Production By A Packed-Bed Anaerobic Digester Fed Dairy Barn Flush Water, Sean Richard Thomson

Master's Theses

Packed-bed digesters are an alternative to covered lagoon digesters for methane production and anaerobic treatment of dilute wastewaters such as dairy barn flush water. The physical media of packed-beds retain biofilms, often allowing increased treatment rates. Previous studies have evaluated several types of media for digestion of dilute wastewaters, but cost and media fouling have setback commercial development. A major operational cost has been effluent recirculation pumping.

In the present effort, a novel approach to anaerobic digestion of flush dairy water was developed at pilot-scale: broken walnut shells were used as a low-cost packed-bed medium and effluent recirculation was replaced …


Quantifying Economic Benefits For Rail Infrastructure Projects, Suzanna Long, Ruwen Qin, John Betak, Akhilesh Ojha, John J. Myers Oct 2014

Quantifying Economic Benefits For Rail Infrastructure Projects, Suzanna Long, Ruwen Qin, John Betak, Akhilesh Ojha, John J. Myers

Engineering Management and Systems Engineering Faculty Research & Creative Works

This project identifies metrics for measuring the benefit of rail infrastructure projects for key stakeholders. It is important that stakeholders with an interest in community economic development play an active role in the development of the rail network. Economic development activities in both rural and urban settings are essential if a nation is to realize growth and prosperity. Many communities have developed goals and visions to establish an economic development program, but they often fail to achieve their goals due to uncertainties during the project selection and planning process. Communities often select a project from a vast pool of ideas …


Analysis Of Different Techniques For Improving Performance Of Flat Plate Solar Collectors For Fruits Drying, Godfrey Mbabaye Jun 2014

Analysis Of Different Techniques For Improving Performance Of Flat Plate Solar Collectors For Fruits Drying, Godfrey Mbabaye

Tanzania Journal of Engineering and Technology (TJET)

Fruits drying had become a broader technology in fruits and vegetables value addition. The technology is reported to be a promising way of drying without incurring higher cost but its adaptation has not been feasible in rural areas. Solar dryers have been developed but its poor performance limits its applicability. In this study, several techniques for modifications of traditional solar collector were addressed. It was observed that, varying collector designs in different techniques, a range of collector performances can be archived. The research shows that, collector efficiency can be improved by 9.6% when employing double duct counter flow compared to …


Noise Pollution In Maize Milling Smes, Erasto Elias Jun 2014

Noise Pollution In Maize Milling Smes, Erasto Elias

Tanzania Journal of Engineering and Technology (TJET)

Maize milling SMEs emit high levels of noise which can have adverse effects on human beings and therefore require controlling. This paper reports on a study that involved assessment and measurement of noise level in maize milling SMEs in DSM and Morogoro urban, gathering opinions of workers and the neighbouring population on noise problems, and suggesting solutions for noise control. Noise measurements in 41 SMEs were recorded from 89-103 dBA in DSM and 92-103 dBA in Morogoro near the milling machines. These values were higher than the safe level of 85 dBA for 8 hours working shift. Measurement also indicated …


Lemongrass And Cinnamon Essential Oils As Vitamin C Preservatives And Flavour Enhancers In Jam, Denice Byarushengo Jun 2014

Lemongrass And Cinnamon Essential Oils As Vitamin C Preservatives And Flavour Enhancers In Jam, Denice Byarushengo

Tanzania Journal of Engineering and Technology (TJET)

Lemongrass and cinnamon essential oils (LEO and CEO) are natural oils with high anti oxidation capacity, pleasant flavour, and various health benefits. Their ability to preserve vitamin C and flavour in jam have not been tested. In this study the performance of two essential oils (EOs) in preserving vitamin C and improving jam flavour were investigated. The EOs were produced by hydro-steam distillation of fresh lemongrasses and cinnamon leaves using a Clevenger apparatus. Jam samples were dosed with various concentrations of either single or mixed EOs and then stored at either room or refrigeration temperature. Samples were analysed for changes …


Multi-Criteria Decision Modeling For Best Value Selections In Target Value Design Integrated Project Delivery, Brent Patrick Griffis Jun 2014

Multi-Criteria Decision Modeling For Best Value Selections In Target Value Design Integrated Project Delivery, Brent Patrick Griffis

Master's Theses

Integrated Project Delivery (IPD) combined with Target Value Design (TVD) is a better way to deliver value for the client than traditional guaranteed maximum price (GMP) methods. With traditional GMP delivery methods, the interests of the parties are often at odds. The goal of IPD is to align all party interests in order to achieve a win-win scenario. Due to the aligning nature of IPD and the fact that each party’s success is dependent on achieving the project objectives as a whole; a non-biased, transparent, decision-making process is necessary in order to deliver the project objectives within the constraints of …


Painted Rumble Stripes: Alternatives To Raised Pavement Markers (Rpms), Thomas M. Brennan Jr, Stuart R. Mikey, Darcy M. Bullock Jan 2014

Painted Rumble Stripes: Alternatives To Raised Pavement Markers (Rpms), Thomas M. Brennan Jr, Stuart R. Mikey, Darcy M. Bullock

JTRP Posters

This poster highlights research completed by the Joint Transportation Research Program (JTRP) led by Darcy Bullock, Lyles School of Civil Engineering, Purdue University, for JTRP Project SPR-3528, "Alternatives to Raised Pavement Markers (RPMs)." The poster includes photos taken at a construction site on State Road 25 located near Shadeland, Indiana. The top photo demonstrates how the center line corrected a driver when snow covered to avoid oncoming traffic. Photo was taken on US 231 near Country Road 800 in Tippecanoe County.


2013-14 Indiana Interstate Mobility Summary, Steve M. Remias, Howell Li, Darcy M. Bullock Jan 2014

2013-14 Indiana Interstate Mobility Summary, Steve M. Remias, Howell Li, Darcy M. Bullock

JTRP Posters

These posters highlight the speed and mobility metrics on four of Indiana’s interstates (I-94, I-65, I-465, and I-70). The posters are part of the effort by the Indiana Department of Transportation to characterize mobility concerns on the statewide interstate system.


Striping Truck Utilization Project, Jon R. Padfield, James Handy Jan 2014

Striping Truck Utilization Project, Jon R. Padfield, James Handy

JTRP Posters

This poster highlights research completed by the Joint Transportation Research Program (JTRP) led by Jon Padfield and James Handy, Purdue University for JTRP project SPR-3722, “Striping Truck Utilization for Crawfordsville and Greenfield District.” This poster highlights the transformation of striping trucks at both districts using Value Stream Mapping (VSM) through the Technical Assistance Program.


Parameterizing Analytical Models To Support An Empirically Based Warehouse Design Methodology, Lisa Thomas Aug 2013

Parameterizing Analytical Models To Support An Empirically Based Warehouse Design Methodology, Lisa Thomas

Graduate Theses and Dissertations

Research in the area of warehouse design is characterized by a myriad of analytical models that address one, typically small and isolated, area of the warehouse. These models, although important in gaining insight into one question of warehouse design, are of limited value when one considers the larger question of overall warehouse design. Thus, research in the area of overall warehouse design typically consists of procedure-driven processes based on qualitative factors and not the quantifiable results of analytical models.

In contrast, practitioners have significant empirical data related to how a design alternative performs in an industry, a company, or a …


Calibration Of Microscopic Traffic Flow Models Considering All Parameters Simultaneously, Victor Hugo Molano Paz Aug 2013

Calibration Of Microscopic Traffic Flow Models Considering All Parameters Simultaneously, Victor Hugo Molano Paz

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study proposes a methodology to calibrate microscopic traffic flow simulation models. The proposed methodology has the capability to calibrate simultaneously all the calibration parameters as well as demand patterns for any network topology. These parameters include global and local parameters as well as driver behavior and vehicle performance parameters; all based on multiple performance measures, such as link counts and speeds. Demand patterns are included in the calibration framework in terms of turning volumes.

A Simultaneous Perturbation Stochastic Approximation (SPSA) algorithm is proposed to search for the vector of the model‟s parameters that minimizes the difference between actual and …


Isolation And Characterisation Of Micro-Organisms With Industrial Importance From Sisal Bole Rots, Consolatha Mhaiki Jun 2013

Isolation And Characterisation Of Micro-Organisms With Industrial Importance From Sisal Bole Rots, Consolatha Mhaiki

Tanzania Journal of Engineering and Technology (TJET)

Investigation of microorganisms naturally acclimatized to Agave hybrid H 11648 (sisal bole rot) was conducted, with the aim of isolating and characterizing Aspergillus niger strains for industrial use. Microorganism were identified morphologically and then confirmation made by polymerase chain reaction (PCR). Results showed the existence of four major groups, listed in order of abundances as follows; Aspergilli (36.0±0.8) %, Penicillin (28.0±0.1) %, Yeast (15.0±1.6) %and Fusarium (10.0±0.12) %. The main groups of Aspergilli strains were A. nidulans, A. tamari and A. niger in ratios (3:2:2), respectively. Several endo-spore forming non-enteric gram (-) rods and coccid bacteria identified by API 20 …


Improvement Of Hydraulic Press For Vegetable Oil Expression In Rural Areas, I. P. Bateebe Jun 2013

Improvement Of Hydraulic Press For Vegetable Oil Expression In Rural Areas, I. P. Bateebe

Tanzania Journal of Engineering and Technology (TJET)

Cultivation of oil producing crops especially Jatropha and croton as source of vegetable oil for biodiesel production is being encouraged in rural areas. To recover oil from seed, manual press is the feasible method in rural areas where there is no electricity. Research was conducted to improve hydraulic oil press machine for rural application. Factors affecting oil recovery were found to be: moisture content of seeds, operating pressure, seed oil content, and the amount of seeds pressed per batch. Percentage oil recovery was improved by reducing diameter of press cylinder, hence increasing expression pressure, and either reducing amount of seed …


College Of Engineering Senior Design Competition Spring 2013, University Of Nevada, Las Vegas May 2013

College Of Engineering Senior Design Competition Spring 2013, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Senior Design Experience

Part of every UNLV engineering student's academic experience, the Senior Design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs and prototypes a product in this required element of the curriculum. Working in teams, the senior design project encourages students to use everything learned in the engineering and computer design programs to create a practical, real world solution to an engineering challenge.

Beyond the classroom ...

Because of the requirement to work in teams, students also build good communication skills, presentation skills and even business writing skills. They also have to …


Assessment Of Solar Photovoltaic Technologies Using Multiple Perspectives And Hierarchical Decision Modeling, Nasir Jamil Sheikh Apr 2013

Assessment Of Solar Photovoltaic Technologies Using Multiple Perspectives And Hierarchical Decision Modeling, Nasir Jamil Sheikh

Dissertations and Theses

The objective of this research is to build a decision model for a comprehensive assessment of solar photovoltaic technologies using multiple perspectives. These perspectives include: social, technological, economic, environmental, and political (STEEP) with each perspective consisting of multiple criteria. Hierarchical decision modeling and expert judgment quantification are used to provide the relative ranking of the perspectives and criteria. Such modeling is effective in addressing technology evaluations with competing and contrasting perspectives and criteria where both quantitative and qualitative measurements are represented. The model is then operationalized by constructing desirability functions for each criterion. The combined results provide an overall numerical …


Simulation Modeling And Analysis Of Complex Port Operations With Multimodal Transportation, Mariam Kotachi, Ghaith Rabadi, Mohammad F. Obeid Jan 2013

Simulation Modeling And Analysis Of Complex Port Operations With Multimodal Transportation, Mariam Kotachi, Ghaith Rabadi, Mohammad F. Obeid

Engineering Management & Systems Engineering Faculty Publications

World trade has been increasing dramatically in the past two decades, and as a result containers exchange has grown significantly. Accordingly, container terminals are expanding to meet this increase and new container ports have opened. Ports with one or more container terminals are considered complex systems in which many resources, entities and transporters interact to achieve the objective of safely moving containers delivered by ships inland as well as loading containers delivered by trucks and rail onto ships. Ports with multimodal transportation systems are in particular complex as they typically operate with ships arriving to one or more terminals, multiple …


Investigation Into The Measure, Correlate And Predict Methodologies Used In Wind Farm Design Software, Brendan O'Sullivan Jan 2013

Investigation Into The Measure, Correlate And Predict Methodologies Used In Wind Farm Design Software, Brendan O'Sullivan

Theses

This paper is focused on the Measure Correlate and Predict (MCP) methodologies used to estimate long term wind resource at a prospective site. The first common step in all MCP methodologies is a successful wind measurement campaign at the prospective site. This campaign involves the erection of a wind measurement mast (ideally to the hub height of the proposed turbine) and careful selection of booms, mountings and anemometers. The wind measurement campaign is a vital part of the process as the correlation and prediction analysis is only as accurate as the measured wind data. Correlation is a measure of the …


College Of Engineering Senior Design Competition Fall 2012, University Of Nevada, Las Vegas Dec 2012

College Of Engineering Senior Design Competition Fall 2012, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Senior Design Experience

Part of every UNLV engineering student's academic experience, the Senior Design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs and prototypes a product in this required element of the curriculum. Working in teams, the senior design project encourages students to use everything learned in the engineering and computer design programs to create a practical, real world solution to an engineering challenge.

Beyond the classroom ...

Because of the requirement to work in teams, students also build good communication skills, presentation skills and even business writing skills. They also have to …


Applications Of Cobb-Douglas Production Function In Construction Time-Cost Analysis, Ashkan Hassani Dec 2012

Applications Of Cobb-Douglas Production Function In Construction Time-Cost Analysis, Ashkan Hassani

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

Cobb-Douglas Production Function was widely used in economics and productivity studies across many sectors. The function’s quantitative modeling of resource inputs and production outputs is appealing to the research domain of construction management. In this thesis we explored this function’s application in construction schedule crashing and project risk analysis related to duration of construction projects. Existing research on construction time-cost tradeoff issues rarely explore the origin of the crashing cost which is defined as the cost needed to shorten the project to the desired duration. In the existing literature crashing cost function was either assumed without much justification, or came …


Optimization Models And Algorithms For Truckload Relay Network Design, Hector Andres Vergara Arteaga Aug 2012

Optimization Models And Algorithms For Truckload Relay Network Design, Hector Andres Vergara Arteaga

Graduate Theses and Dissertations

Driver turnover is a significant problem for full truckload (TL) carriers that operate using point-to-point (PtP) dispatching. The low quality of life of drivers due to the long periods of time they spend away from home is usually identified as one of the main reasons for the high turnover. In contrast, driver turnover is not as significant for less-than-truckload (LTL) carriers that use hub-and-spoke transportation networks which allow drivers to return home more frequently. Based on the differences between TL and LTL, the use of a relay network (RN) has been proposed as an alternative dispatching method for TL transportation …


Probabilistic Resilience Quantification And Visualization Building Performance To Hurricane Wind Speeds, Berna Eren Tokgoz Jul 2012

Probabilistic Resilience Quantification And Visualization Building Performance To Hurricane Wind Speeds, Berna Eren Tokgoz

Engineering Management & Systems Engineering Theses & Dissertations

Natural and man made disasters are unpredictable and unavoidable in today's world. Their frequency of occurrence and damages keep increasing. Due to the efforts to reduce negative consequences from such disasters, the concept of resilience has gained so much popularity in disaster management area especially after disasters like the September 11 attacks and Hurricane Katrina. Complex systems of today are under operational risks because of increasing threats and their high level of vulnerability. Hence, such systems need to adapt the concept of resilience for continuous operations. Resilience is a proactive concept which should incorporate both pre-event (preparedness and mitigation) and …