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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.
1

A METHOD FOR ASSESSING THE TRIBOLOGICAL PERFORMANCE OF TOOL AND WORKPIECE INTERACTIONS

Aliakbari Khoei, Ali January 2019 (has links)
Friction in machining is a complex phenomenon that can directly affect cutting productivity and product quality. Currently, different coatings are developed for machining applications which can increase tool life in the machining processes. Since performing a real machining test to quantify the friction is expensive and time-consuming, developing a bench scale testing method to simulate the friction in machining can reduce the cost and help researchers and industries select a suitable coating for their specific applications. The goal of this work was to study the adhesion between the tool and workpiece material under machining conditions by simulating them using a heavy-load high-temperature tribometer. A high normal load was applied to plastically deform the workpiece material. The contact zone was then heated up using a resistance heating method. The normal load should be in the range that can generate a plastic flow on the surface of the workpiece material prior to seizure. Three groups of in-house coatings were tested to study the effects of coating deposition parameters on the coefficient of friction. The results of these tests showed that the coating with the lowest bias voltage and highest Nitrogen pressure had the best tribological performance. As a next step, three different commercial coatings were selected. Super duplex stainless steel was chosen as the workpiece material and the tribometer tests were performed. To validate the tribometer results real machining tests and tool wear analysis were performed. AlTiNOS+ WC/C was observed to be a lubricious coating which reduced the cutting force and coefficient of friction during the running-in stage. However, the low hardness of the coating provided little abrasion resistance and was removed after the first pass. AlTiNOS+ TiB2 demonstrated a good combination of hardness and lubricity associated with improved coating tribological performance as well as wear resistance. / Thesis / Master of Applied Science (MASc)
2

Proyecto Cargo Fast

Benavides Castro, Jose Antonio, Huayaney Gilio, Elizabeth, Ortecho Paredes, Gustavo, Zamudio Castillo, Lincoln, Rodríguez Morales, Pedro José 02 March 2022 (has links)
El presente proyecto de diseño e implementación de un aplicativo móvil para el transporte de carga pesada, de alto volumen y con requerimientos específicos muestra la viabilidad de ejecución, en base a las investigaciones realizadas en Lima Metropolitana para los NSE “A” y “B”, las cuales permitieron identificar la necesidad tanto por personas naturales como jurídicas por localizar y contratar servicios de transporte para muebles, enseres, indumentaria, insumos y productos de manera rápida y segura, frente a un mercado principalmente informal de ofertantes, con plazos de espera altos y de difícil contacto donde, actualmente, predomina la publicidad del tipo “boca a boca”, con tarifas poco estandarizadas. Así mismo, se identificó la necesidad por parte de transportistas de mantener un flujo constante en las actividades de sus flotas terrestres, existiendo un amplio tiempo de inmovilización de sus vehículos ocasionando altos costos de oportunidad. Adicionalmente, se observó que, en su mayoría, las unidades de transporte en circulación pertenecientes al rubro de carga pertenecen a terceros, los cuales gestionan su uso a través de arrendamientos o a través de la contratación de conductores, existiendo incertidumbre respecto a la integridad del vehículo y su uso, con escasas opciones en el monitoreo de conducción. Finalmente, se encontró un crecimiento significativo en la adquisición de teléfonos inteligentes y la descarga y uso de aplicativos del tipo on-demand, orientados al contacto entre clientes y proveedores de servicios de recepción y entrega de artículos, así como movilización, no existiendo un aplicativo orientado a la carga y transporte de artículos de alto volumen o peso, o con necesidades específicas como refrigeración o carga delicada. Con el fin de atender dichas demandas de mercado, se puso en marcha el proyecto Cargo Fast, aplicación que facilita el contacto entre usuarios y proveedores de servicios de carga diversa, mediante un aplicativo on-demand el cual ofrece el servicio de seguimiento de transportes en tiempo real, ubicación de ofertantes cercanos, calificación de conductores, aseguramiento de artículos y pago mediante medios digitales bancarizados. En adición, el aplicativo facilita al proveedor en la gestión de servicios, brindando de manera adicional reportes orientados al perfil del usuario y su conducción, de principal interés para los dueños de vehículos y administrativos pertenecientes a las empresas proveedoras de transportes. Para poner en marcha la implementación de este proyecto se realizó un análisis de la industria: consumidor, proveedores, competidores y otros factores externos. Además, se desarrollaron los siguientes planes: Plan Estratégico, Plan de Operaciones, Plan de Marketing y Plan Financiero, los cuales contienen las estrategias necesarias para la viabilidad de este proyecto. Como resultado, luego de una inversión inicial de S/125,000, en el primer año de operaciones se obtendrá una pérdida neta de S/86,344 y una utilidad neta de S/134,806 para el segundo año, S/269,053 para el tercer año, S/458,726 para el cuarto año y S/544,849 para el quinto año. / The present project of design and implementation of a mobile app for the delivery of heavy cargo, high volume and cargo with specific requirements shows the feasibility of execution, based on the investigations carried out in Lima Metropolitana for the economic social level "A" and "B" , which allowed us identify the need for both natural and legal persons to locate and hire transport services for furniture, fixtures, clothing, supplies and products quickly and safely, compared to a mainly informal market of bidders, with long waiting times and difficult contact where, currently, “word of mouth” advertising predominates, with little standardized rates. Likewise, the need for carriers to maintain a constant flow in the activities of their land fleets was identified, since there is a long period of immobilization of their vehicles, causing high opportunity costs. Additionally, it was observed that most of the transport units in circulation belonging to the cargo category are owned by third parties, which manage their use through leases or through the hiring of drivers, with uncertainty regarding the integrity of the vehicle and its use, with few options in driving monitoring. Finally, a significant growth was found in the acquisition of smartphones and the download and use of on-demand applications, aimed to contact customers and service providers for receiving and delivering items, as well as mobilization, with no application oriented to the loading and transport of high-volume or heavy items, or with specific needs such as refrigeration or delicate cargo. To meet these market demands, the Cargo Fast project was launched, an application that facilitates contact between users and providers of diverse cargo services, through an on-demand application which offers transport tracking service in real time, location of nearby bidders, driver rating, item insurance and payment through banked digital means. In addition, the application facilitates the provider in the management of services, additionally providing reports oriented to the user's profile and their driving skills, of main interest to vehicle owners and administrators belonging to transport provider companies. To start the implementation of this project, an analysis of the industry was carried out: consumer, suppliers, competitors, and other external factors. In addition, the following plans were developed: Strategic Plan, Operations Plan, Marketing Plan and Financial Plan, which contain the necessary strategies for the viability of this project. As a result, after an initial investment of S/125,000, in the first year of operations a net loss of S/86,344 will be obtained and a net profit of S/134,806 for the second year, S/269,053 for the third year, S/458,726 for the fourth year and S/544,849 for the fifth year. / Trabajo de investigación

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