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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Identifying Factors and Quantifying their Impact on Transportation Costs of Pre-Processes Biomass

Gonzales, Daniela Sofia 11 August 2012 (has links)
This research presents a rail transportation cost analysis of bulk agricultural commodities (such as grain and wood chips) with similar characteristics as pre-processed biomass. This study analyzes the cost factors that affect rail pricing for shipments of bulk-commodities (such as grain) from the Midwest to various regions in the US using regression analysis theories. The rail cost equations developed from the regression analysis were used to compare the trade-offs that exist between truck, rail and barge transportation of pre-processed biomass.
112

Selective Diesel Oxidation Catalysts for Hydrocarbons

Erwe, Karolin January 2012 (has links)
No description available.
113

The Food Hub as a Social Infrastructure Framework: Restitching Communities in Boston After the Pandemic

Tiches, Connor J 09 August 2023 (has links) (PDF)
Food culture has long been a fundamental part of the city; as a culturally cohesive urban infrastructure, food culture creates integral shared experiences and is a generator of socioeconomic opportunity. During the COVID-19 pandemic, existing systemic issues of racial segregation and isolation have exacerbated growing concerns of food insecurity within prominent minority neighborhoods of Boston, Massachusetts. The instability created by the lockdown and consequential work-life culture shift reinforces the importance of establishing and maintaining equitable and sustainable pathways of access to food resources and the socioeconomic opportunities food culture can create. To promote resilience in the post-COVID-19 lockdown city, urban environments will need to be reimagined to incorporate social and economic infrastructures that promote flexibility and maximize entrepreneurial equity, diversity, and opportunity. As a driving force of this equitable change in Jamaica Plain and the surrounding neighborhoods, this thesis proposes a new sustainable food system that is in tune with the regions storied ecological landscapes as well as the current need for mobility in post-COVID-19 urban life. To bridge the gap between historically fragmented regions of the urban fabric, this thesis will propose an infrastructural landmark designed to support the proliferation of food cultures, enhance housing, industrial, and ecological infrastructures, as well as bike and pedestrian mobility to restitch the greater urban fabric of the city of Boston. This thesis explores the reorganization of a range of modalities of urban food culture into a comprehensive food hub. The Food Hub and associated program will serve as an incubator of socioeconomic opportunity as well as operate as a system of sustainable production and distribution aimed at creating food sovereignty amongst members of the community. The resolution of these analyses will culminate in an architectonic framework for food culture programs that are primed to support the sustainable and equitable flow of resources, users, and ideas between disparate communities.
114

Truck Modeling Along Grade Sections

Lucic, Ivana 29 May 2001 (has links)
This research effort first characterizes the trucks traveling along US highways by analyzing data from Interstate 81. It is hypothesized that I-81 is typical of US highways and thus can provide some insight into typical truck characteristics. These truck characteristics are important for the development of an exhaustive vehicle performance procedure. Analysis was done based on data collected at the Troutville weigh station. The characterization involves an analysis of vehicle class distribution, GVW (Gross Vehicle Weight) distribution, vehicle volume distribution, Average Weight on Tractive Axle (AWTA), and typical weight-to-power ratios. The thesis then assembles a database of systematic field data that can be utilized for the validation of vehicle performance models. This database is unique because it was conducted in a controlled field environment where the vehicle is only constrained by its dynamics. Using the assembled field database, a simple constant power vehicle dynamics model for estimating maximum vehicle acceleration levels based on a vehicle's tractive effort and aerodynamic, rolling, and grade resistance forces was tested and validated. In addition, typical model input parameters for different vehicle, pavement, and tire characteristics are included in the thesis. The model was found to predict vehicle speeds at the conclusion of the travel along the section to within 5 km/h (3.1 mi/h) of field measurements, thus demonstrating the validity and applicability of the model. Finally, the research effort introduces the concept of variable power in order to enhance current state-of-the-art vehicle dynamics models and capture the build-up of power as a vehicle engages in gearshifts at low travel speeds. The proposed enhancement to the current state-of-practice vehicle dynamics model allows the model to reflect typical vehicle acceleration behavior more accurately. Subsequently, the model parameters are calibrated using field measurements along a test roadway facility. / Master of Science
115

Gourmet Food Trucks: An Ethnographic Examination Of Orlando's Food Truck Scene

Hawk, Zachary 01 January 2013 (has links)
Gourmet food trucks have emerged as increasingly popular dining alternatives for consumers in today’s urban landscape. Existing literature, as well as my own ethnographic research within Orlando, Florida’s mobile food vending scene, reveals that food truck owner/operators utilize various strategies to establish a viable niche for themselves in this diversified and burgeoning market. Among other things, these strategies include online social networking, creating and maintaining a recognizable brand identity, collaborating with local retailers and bar owners, and incorporating organic and locally produced ingredients in their dishes whenever possible. As in other parts of the country, there appears to be a growing concern in greater Orlando about local diets and the profound and subtle messages it conveys about contemporary eating habits. I contend that dining at gourmet food trucks represents a legitimate declaration of consumer identity about individual beliefs and values. In my thesis, I examine how Orlando’s gourmet food trucks offer consumers a greater selection of food options and allow locals to participate in a viable social network and community.
116

THE ROLE OF PLATOONING IN FREIGHT TRANSIT EFFICIENCY

Alshiddi, Reem 01 May 2023 (has links) (PDF)
With the progress and expansion of civilization, companies are interested in distributing their products and goods in distributed areas on a daily basis. These daily tasks are considered to ensure that the products reach the largest possible number of people to keep pace with accommodating the expansion and population. However, these daily duties demand a lot of effort and are financially burdened on both drivers and companies as well. Besides that, daily transportation might cause traffic congestion as well as being negative on the environment with harmful emissions coming from heavy-duty trucks. With overcrowding, companies may face delays in the arrival of their products to their customers, which is a point that may reflect negatively on the company's reputation in the business. One of the proposed solutions for companies to deal with these problems is to create a platoon of trucks during their transportation between the pickup stations and the drop-off stations. The literature review demonstrates that there are written benefits for the truck platoons, however, there is a lack of showing these benefits in the reality. The platoon simulation was built in this thesis to present the results numerically so that they could be contrasted with scenarios where the platoon was not used for freight transportation. This thesis focused on the benefits of a platoon from three aspects: the aspect of saving time, reducing cost by reducing fuel usage, and finally increasing safety in public driving on highways. The results of using the simulations showed that the time was using to deliver the goods by using truck platoons was shorter than the time by using individual trucks. Additionally, traffic congestion was less when the trucks were driven on single-lane on highways, which causes reduced the number of accidents especially, those that occurred with small cars. They compiled accident data between 2007 and 2017, coming to the conclusion that 98,790 crashes involving large trucks were among the 243,017 total crashes. In the same survey, the authors found that 9.4% of truck accidents occurred when changing lanes with small cars on highways. This thesis demonstrated numerically that there was less fuel usage while the trucks were driven in a platoon compared with the fuel usage of the trucks that were driven individually. In a word, transportation companies will gain benefits from using truck platoons to deliver their goods to their customers.
117

Investigation of the potential of e-axles for trucks / Undersökning av potentialen för e-axlar för lastbilar

Fernandez Carnota, Marina January 2020 (has links)
As a step to reduce emissions of trucks, Scania investigates different solutions related to electrification to contribute with more environmental friendly vehicles. The aim of this project is to investigate the potential of electrified axles, e-axles, to use in Scania trucks. Not only from a performance point of view but also from a business and industrialisation point of view. The e-axle is a compact unit which integrates an electric motor, power electronics and transmission. It is used as a power source for the vehicle and it is a more efficient solution for the electric vehicles, eliminating losses and saving space. Through a market analysis, gathering of information and knowledge about electrified solutions for trucks, interviews with Scania staff and product specification five different concept are identified, evaluated and compared. These concepts are the following:   Concept 1- Electric motor within a mechanically driven axle   Concept 2- Electric motors in a non-driven axle   Concept 3- In-wheel motors   Concept 4- Electric motors in a rear support axle   Concept 5- Electric motor in a diesel truck with a generator A concept selection matrix was set-up to find the best solution. In the evaluation of the concepts different CAD models are developed, based on mainly existing models at Scania. The difference between the concepts is based on the different axle possibilities to locate the electric motors. The best two concepts were identified as concept 2 and concept 4. For future work, the two best concepts should be used for a deeper study, obtaining a final design layout and realising an structure analysis of them to verify the designs. The market analysis shows that there will be a market for the product, but it will require an extensive design and development phase. This thesis sets the ground for the development of a new product towards the electrification of trucks. / Som ett steg för att minska utsläppen från lastbilar undersöker Scania olika lösningarrelaterade till elektrifiering för att bidra med mer miljövänliga fordon. Syftet med dettaprojekt är att undersöka potentialen hos elektrifierade axlar, e-axlar, att använda i Scaniaslastbilar, inte bara ur prestandasynpunkt utan även ur affärs- och industrialiseringssynpunkt.E-axeln är en kompakt enhet som integrerar en elmotor, kraftelektronik ochtransmission. Den används som en kraftkälla för fordonet och är en mer effektiv lösningför elfordonen, vilket eliminerar förluster och sparar utrymme.Genom en marknadsanalys, insamling av information och kunskap om elektrifierade lösningarför lastbilar, intervjuer med Scanias personal och produktspecifikation har fem olikakoncept identifieras, utvärderas och jämförts. Dessa koncept är följande:  Koncept 1- Elektrisk motor i en mekaniskt driven axel  Koncept 2- Elektriska motorer i en icke-driven axel  Koncept 3- Hjulmotorer  Koncept 4- Elektriska motorer i en bakre stödaxel  Koncept 5- Elmotor i en diesel lastbil med en generator En konceptvalsmatris sattes upp för att hitta den bästa lösningen. Vid utvärderingen avkoncepten utvecklas olika CAD-modeller baserade på huvudsakligen befintliga modellerpå Scania. Skillnaden mellan koncepten baseras på de olika axelmöjligheterna för attplacera elmotorerna. Det bästa konceptet identifierades som koncept 2 och koncept 4.För framtida arbete bör de två bästa koncepten användas för en djupare studie, för att fåen slut lig design layout och genomföra en strukturanalys av dem för att verifiera designen.Marknadsanalysen visar att det kommer att finnas en marknad för produkten, men detkommer att kräva en omfattande design- och utvecklingsfas. Detta examensarbete läggergrunden för utvecklingen av en ny produkt mot elektrifiering av lastbilar.
118

Modeling Truck Motion along Grade Sections

Yu, Bin 22 March 2005 (has links)
Roadway grades have a diverse effect on vehicle speeds, depending on vehicle and roadway characteristics. For example, passenger cars can generally negotiate grades of 5 percent or less without considerable reductions in vehicle speeds, while heavy-duty trucks are affected significantly by grades because of their inferior operating capability. Consequently, due to the potential significant speed differential between automobiles and heavy-duty trucks, these trucks can have a significant impact on the quality of flow, throughput, and safety of a traffic stream. Truck climbing lanes are typically constructed in an attempt to lessen this negative impact. Currently, the American Association of State Highway and Transportation Officials (AASHTO) and Highway Capacity Manual (HCM) represent the state-of-art and state-of-practice procedures for the design of truck climbing lanes. These procedures only consider the tangent vertical profile grades in the design of climbing lanes and do not capture the impact of vertical curvature on truck performance. The dissertation describes the TruckSIM framework for modeling vehicle motion along roadway sections by considering both the longitudinal and lateral forces acting on a vehicle. In doing so, the tool reflects the impact of horizontal and vertical alignment on a vehicle's longitudinal motion. The model is capable of reading Global Positioning System (GPS) (longitude, latitude, and altitude), roadway, and vehicle data. The dissertation demonstrates the validity of the software modeling procedures against field data and the HCM procedures. It is anticipated that by automating the design procedures and considering different vehicle and roadway characteristics on truck motion, the TruckSIM software will be of considerable assistance to traffic engineers in the design of roadways. The Global Positioning System (GPS) was originally built by the U.S. Department of Defense to provide the military with a super-precise form of worldwide positioning. With time, GPS units were introduced into the civilian domain and provided transportation professionals with an opportunity to capitalize on this unique instrumentation. With this GPS capability, this research investigates the feasibility of using inexpensive WAAS-capable units to estimate roadway vertical and horizontal profiles. The profiles that are generated by these inexpensive units (less than $500) are compared to the profiles generated by expensive carrier-phase DGPS units ($30,000 per unit including the base station). The results of this study demonstrate that the use of data smoothing and stacking techniques with the WAAS data provides grade estimates that are accurate within 10% of those generated by the carrier-phase DGPS units and thus offer a cost effective tool for providing input data to the TruckSIM software. Using the TruckSIM software, this research effort investigates truck performance reflective of various truck and road characteristics. These characteristics include vehicle engine power, weight-to-power ratio, pavement type, pavement condition, aerodynamic aid features, engine efficiency, tire type, and percentage mass on tractive axle. The study demonstrates that the vehicle weight-to-power ratio, vehicle engine power, pavement surface condition, tire type, aerodynamic aids, and engine efficiency are critical factors in the design of truck climbing lanes. / Ph. D.
119

Semiactive Cab Suspension Control for Semitruck Applications

Marcu, Florin M. 29 April 2009 (has links)
Truck drivers are exposed to vibrations all day as a part of their work. In addition to repetitive motion injuries the constant vibrations add to the fatigue of the driver which in turn can have safety implications. The goal of this research is to lower the vibrations an occupant of a class 8 semitruck cab sleeper is exposed to by improving the ride quality. Unlike prior research in the area of ride comfort that target the chassis or seat suspension, this work focuses on the cab suspension. The current standard in cab suspensions is comprised of some type of spring and passive damper mechanism. Ride improvements can most easily be accomplished by replacing the stock passive dampers with some type of controllable damper; in this case Magneto-Rheological (MR) dampers. MR dampers can change damping characteristics in real time, while behaving like a passive damper in their OFF state. This means that in case of a failure to the power supply, the dampers still retain their functionality and can provide some level of damping. Additionally, MR dampers can be packaged such that they do not require any redesign of mounting bracketry on the cab or the frame, their use as a retrofitable device. The damper controller is based on the skyhook control policy pioneered by Karnopp et al. in the 1970s. A variation on skyhook control is chosen called no-jerk skyhook control. A controller called Hierarchical SemiActive Control (HSAC) is designed and implemented to allow the no-jerk skyhook controller to adapt to the road conditions. It also incorporates an endstop controller to better handle the limited rattle space of the cab suspension. The development and initial testing of the controller prototype is done in simulation using a model of the cab and its suspension. The model is derived from first principles using bond graph modeling. The controller is implemented in Simulink to ease the transition to hardware testing. The realtime prototype controller is tested on a class 8 semitruck in a lab environment using dSPACE and road input at the rear axles. The laboratory results are veried on the road in a series of road tests on a test truck. The road tests showed a need for HSAC controller. The HSAC is implemented on the test truck in a final prototype system. The test results with this system show signfiicant improvements over the stock passive suspension, especially when dealing with transient excitations. The overall research results presented show that significant ride improvements can be achieved from a semiactive cab suspension. / Ph. D.
120

Evaluating the Effectiveness of Electronic Stability Systems in Reducing Truck Rollovers

Donoughe, Kelly Marie 19 January 2011 (has links)
The objective of this research is to develop a customized hardware-in-the-loop system that is used to test Electronic Stability Program (ESP) systems to prevent heavy truck rollovers when navigating horizontal roadway curves. While most of the published literature on electronic stability control focuses on the effectiveness of stability systems in passenger cars, very few researchers have considered its application as it pertains to commercial vehicles. Detailed crash data that have been extracted from the crashes that are represented in the Large Truck Crash Causation Study database have been used to draw conclusions regarding the main cause of the crashes and the geometry of the road upon which the crashes occurred. Those crash scenarios were run through a hardware-in-the-loop system that communicates between the TruckSim software, a vehicle dynamics based simulation program, and a real-time tractor-trailer braking rig. The simulations were first run without the ESP enabled to determine the critical speed which will cause the truck to roll, then the same simulation runs were executed with the Bendix stability system enabled to determine the difference in speeds in which a rollover is inevitable with and without the technology. A third speed that represents the lowest speed in which the stability system activates was also determined. As requested by the National Highway Traffic Safety Administration (NHTSA), this study also serves as a comparison between the Bendix system and the Meritor WABCO system which has already been tested by the University of Michigan Transportation Research Institute. / Master of Science

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