Engineering Commons^™

Revisiting The Merseburg Process: Economic Opportunity And Environmental Benefit?, Gary Albarelli

Beneficiation of Phosphates VIII

The process for manufacture of ammonium sulfate from gypsum, known as the Merseburg Process, named for the town in Germany where it was developed, has been commercially produced in plants in Austria, India, Pakistan and the United Kingdom in the past. It is based on reacting ammonia and carbon dioxide to produce ammonium carbonate, which is then reacted with gypsum to produce ammonium sulfate and calcium carbonate. Ammonium sulfate is mainly used as direct fertilizer or in producing compound fertilizers. The global ammonium sulfate market is projected to grow 4% annually through 2025, from $4.6 billion to $6.8 billion. As …

Influence Of The Impeller Speed On Phosphate Rock Flotation, André Carlos Silva, Elenice Maria Schons Silva, Fernanda Santos Andrade

Beneficiation of Phosphates VIII

Flotation represents, at present, the technology capable of efficiently concentrate the minerals of interest, separating them from other gangue minerals. The flotation process is based on interactions between minerals (solid phase), water (liquid phase), and air (gas phase). However, it depends on physical forces driving the system. If mineral particles do not have enough momentum during the collision with the air bubble no attachment between them occurs, and consequently no flotation. Impeller rotation speed is undoubtedly a factor that changes the hydrodynamic conditions of the flotation system playing a vital role on it. It supplies the flotation system with air …

Latest Trend For Fluorine In The Phosphoric Industry: Absorption Efficiency Improvement, Conversion Into Raw Material, Tibaut Theys

Beneficiation of Phosphates VIII

Almost all the phosphate apatite used in the world to produce phosphoric acid trough the wet process contains fluorine. When not properly controlled, this element creates process, health and environmental issues that can have dramatic impact. In recent year several technologies have been established or improved to tackle these challenges.

F absorption has been improved by simple changes that ensure a high efficiency while minimizing the CAPEX.

F usage has also been largely investigated to produce valuable product as AlF3 or HF but also easy to transport raw material as CaF2. This paper will describe some recent development related to …

Alternative Depressor For Apatite Flotation, André Carlos Silva, Débora Nascimento Sousa, Diego Valentim Crescente Cara, Alex Malue Machado, Elenice Maria Schons Silva

Beneficiation of Phosphates VIII

The reality of the phosphate mines in the world has been changing. The reserves content has reduced over the years. As a consequence of this reduction, contaminants such as iron, silica and magnesium contained in phosphate rock concentrate are affecting the stability of the chemical plants, which compromises the rate of phosphate utilization and the quality of the products produced. In order to obtain a concentrate of phosphatic rocks of market acceptable quality (35% P₂O₅), the flotation process is the most suitable method for processing this. The present study aims to evaluate the potential of replacing …

The Surface Chemistry And Microflotation Of Xenotime And Depression Of Gangue Minerals, Corby Anderson, Yicheng Zhang

Beneficiation of Phosphates VIII

A pre-concentrated xenotime sample and four selected gangue minerals, ilmenite, zircon, schorl and staurolite were used in this project. Using Octano-hydroxamic acid as a collector, the surface chemistry was investigated through surface area measurements, zeta potential tests and adsorption density determinations. The results of adsorption studies were then correlated with microflotation tests conducted at room temperature in a Partridge-Smith cell. In this paper, the surface chemistry and microflotation behaviors are then discussed based on both lab observations and a literature review.

Further, because of their selective depressing power, sodium silicate and lignosulfonate have been widely used as depressants in rare-earth …

Using Two Alternative Vegetable Oil’S As Collector In Apatite Froth Flotation, André Carlos Silva, Elenice Maria Schons Silva, Alex Malue Machado, Diego Valentim Crescente Cara, Débora Nascimento Sousa

Beneficiation of Phosphates VIII

The Brazilian phosphate deposits are of igneous origin exhibiting a complex mineralogy where fluorapatite is the predominant mineralogical variety fron the apatite group, this deposits still contain carbonateapatite and hydroxyapatite associated with secondary phosphates, iron oxides (magnetite, goethite and limonite), micas and minerals bearing niobium, titanium and barium. The flotation process as a separation and enrichment of the acceptable levels by the P₂O₅ market (35%) is the most efficient. Brazilian mineral industries use synthetic collectors from international companies. Many of these oils were initially produced to sort out the demand for biodiesel production, with their market being …

Nitrogen And Weed Management In Transplanted Tomato In The Nigerian Forest-Savanna Transition Zone, J. A. Adigun, O. S. Daramola, O. R. Adeyemi, P. M. Olorunmaiye, O. A. Osipitan

Haskell Agricultural Laboratory (Northeast Research and Extension Center)

Weed infestation and inherent low soil fertility are among primary reasons for low yields of tomato in Nigeria. Field trials were carried out during the wet season of 2015 and 2016 to evaluate yield response of tomato to nitrogen (N) application and weed control methods in the forest-savanna transition zone of Abeokuta, Nigeria. Positive relationship exists between growth of weed species and increase in N application. Across the years of study, increase in N up to 90 kg/ha increased weed density by 11–25%, however, the increased N gave the transplanted tomato competitive advantage and thus enhanced weed smothering. Pre-transplant application …

Effect Of Calcium Concentration On Calcite Flotation From Apatite Using Carbonic Gas, Amanda Soares, Suzanne Ferreira De Mello, Rafael Teixeira Rodrigues

Beneficiation of Phosphates VIII

The most widely industrial flotation process for the treatment of phosphate ores containing carbonate as gangue minerals, especially in China, Saudi Arabia, Morocco, use strong acids, such as H₃PO₄ and H₂SO₄ as apatite depressants, and the carbonate minerals (especially calcite and dolomite) are selectively floated with the use of fatty acids as collectors at pH between 5.5 - 6.0. The flotation process currently considered for apatite concentration for the Santa Quitéria ore (Brazil) was developed in the middle of the 1980´s at the Center for Development of Nuclear Technology and involves bulk flotation of …

History And Future Of Phosphate Mining And Beneficiation In South Africa, Marius Porteus

Beneficiation of Phosphates VIII

The major igneous phosphate deposit in Phalaborwa was discovered in 1904. The establishment of the Phosphate Development Corporation (Foskor) in 1951 catalyzed the development and growth of phosphate mining and phosphate fertilizer manufacturing in South Africa as well as associated businesses. This keynote address covers four major topics: 1) chemical and mineralogical properties of major phosphate deposits in South Africa, 2) mining and beneficiation practices, 3) technical challenges and evolution of processing technologies, and 4) future trends.

Experimental Investigation Of Fischer-Tropsch Synthesis With A Modified Catalyst Support, Pawarat Bootpakdeetam

Mechanical and Aerospace Engineering Dissertations - Archive

Energy demand has been rapidly increasing in the last 30 years due to the population growth and high demand by industries. However, as natural energy sources are limited, they cannot meet this increased energy demand. Therefore, alternative energies have become an option to sustain current and future energy demands. One promising and reliable alternative energy is the Fischer-Tropsch synthesis (FTS), which is a gas-to-liquid (GTL) technology that converts syngas from a low-value feedstock, for example, from coal, biomass, or natural gas, into a high-value liquid hydrocarbon. In addition, FTS is a highly exothermic catalytic reaction that requires careful thermal management …

Impacts Of Geotechnical Aspects In Tunneling Design And Construction, Mohammad Haadi Sadaghiani

Civil Engineering Theses - Archive

In tunneling project, different type of methods is conducted to do the project. Knowing geotechnical aspects of tunnel project is unavoidable and crucial in early stage of project especially before contract to have efficient and more accurate design and prevent cost overruns, reduce bid price and reduce project risks. However, all that geotechnical information should be based on standard guidelines such as Geotechnical Baseline Report (GBR) to help owner how to provide those geotechnical data in bid contract and use it as a guideline in contract to prevent future claim or disputes. The main objective of this thesis is about …

Lithium And The Foreseeable Future, Paolo Vargas

Mechanical Engineering Undergraduate Honors Theses

This paper aims to clarify the uncertainties regarding worldwide lithium resource availability in the years to come. Previous studies made on the subject are presented with some ambiguity and this work intends to fill the gaps. The information and data presented throughout this script with respect to global lithium resources and reserves are mostly based on data released by the United States Geological Survey (USGS). Lithium resource availability in the future is a point of paramount significance primarily for the automotive, portable electronics, and the power generation industry. Since, a change of supply would ultimately affect the price of lithium, …

Sustainable Waste Management Through Operating Landfill As Biocell, Naima Rahman

Civil Engineering Dissertations - Archive

Solid waste is being generated at a record pace, and disposal of it requires advanced waste management services at a reasonable cost. Landfilling is the most suitable waste disposal and management technique currently available, and it is being used throughout the world. It is, however, the largest anthropogenic source of atmospheric methane, and it requires a lot of space. The primary objective of this study was to investigate an alternative sustainable solution to waste management by operating landfills as biocells. Biocells are cost effective, produce methane more rapidly, and accelerate space recovery. A laboratory scale study was conducted to investigate …

Mine Arnaud Project: Flotation Circuit Adjustment And Collector Reduction, Christine Croteau, Patrick Laflamme, Michel Lafontaine

Beneficiation of Phosphates VIII

The Mine Arnaud open deposit is located in Sept-Iles in the province of Quebec, Canada. The project, which is currently under development, consists of igneous apatite ore grading around 5% P₂O₅.The target metallurgical performances are set to a concentrate of P₂O₅ grade of at least 39% with an overall P₂O₅ recovery above 90%.The beneficiation of the ore is achieved by grinding to the liberation size, magnetic separation to remove the titaniferous magnetite and phosphate flotation. Most of Mine Arnaud’s apatite beneficiation flowsheet development testwork was realized by COREM. The most …

Effective Resource Utilization In Arkansas Public Schools, Ryan Sanders

Industrial Engineering Undergraduate Honors Theses

Teacher pay in Arkansas public schools varies widely from district to district across the state. This pay discrepancy is driven by both the funds available to a district and by how these funds are allocated. There is a standard per student budget given to districts across the state, but this budget can be supplemented by additional property taxes collected on property within a district. This leaves districts with more highly valued property at an advantage. Districts are free to allocate their budget for teacher pay as they see fit, with constraints on number of students per teacher and minimum teacher …

Identification Of Phase-Based Key Performance Factors And Their Best Practices In Construction Projects, Mohammadreza Habibi

Civil Engineering Theses - Archive

Delay and cost overrun in construction projects are two widespread problems arousing practitioners’ and scholars’ concerns as poor time and cost performance lead construction projects to failure. It is estimated that more than half of the construction industry’s projects encounter significant cost overruns and major delays, resulting in the industry having a tarnished reputation. Despite the attempts of numerous researchers to identify key performance factors, their results have been inconsistent. Most of the literature has focused solely on the construction phase budget and time overruns; the engineering/design and procurement phase costs and schedule performances have been rarely studied. Therefore, the …

An Alternative Method Of Identification Of A Failed Engine In Twin-Engine Propeller Aircraft, Andrey Babin

Doctoral Dissertations and Master's Theses

Previous research has revealed that wrong identification of a failed engine during flight is not an uncommon event in an aircraft cockpit. A number of fatal accidents in the past, including the recent TransAsia Flight 235 accident, resulted from engine misidentification. Most accidents of this type happened on takeoff when pilot workload was at its highest level. This thesis consists of two research studies. For Research Study 1, a survey was created to gather opinions of airline pilots who operate twin-engine turboprop aircraft. Twenty-nine percent of respondents to the survey agreed with the statement that there could be a better …

Low-Fare Flights Across The Atlantic: Impact Of Low-Cost, Long-Haul, Trans-Atlantic Flights On Passenger Choice Of Carrier, Jennifer Nicole Hunt

Doctoral Dissertations and Master's Theses

Full-service carriers (FSCs) have long ruled the trans-Atlantic market, due to the absence of low fare competition, which has kept airfares high. However, renewed interest in low-cost, long-haul (LCLH) flights was prompted by efficient aircraft, low fuel prices, liberalization of air markets, and low-cost carriers’ growth opportunities. Since 2013, multiple LCLH carriers have commenced trans-Atlantic operations, and their market share has grown to 8%. In response, FSCs are establishing their own LCLH subsidiaries and/or introducing basic economy airfares to more effectively compete in the trans-Atlantic market. The purpose of this dissertation was to further the understanding of LCLH and FSC …

Journeyman International – Kalisher Multi-Purpose Center, Chelsea Trumbull

Construction Management

The Kalisher Multi-Purpose Center in Rwanda was completed through a non-profit organization, Journeyman International. Dan and Frances Klinck created a vision for a master plan in the Sunzu Yacu Village in Rwanda and teamed up with Journeyman International to accomplish it. The Kalisher Multi-Purpose Center is the next step in completing their master plan. This center will serve as a place of gathering and community for the locals. It will house various events including, but not limited to: community meetings, private ceremonies, performances, church gatherings, learning opportunities and a space for growth. This project was interdisciplinary and combined efforts from …

Ph Effects On The Sorption Of Fluoxetine And Sulfamethoxazole By Three Powdered Activated Carbons, James D. Schneider

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Pharmaceuticals and personal care products (PPCPs) are widely used throughout the world. PPCPs are emerging as pollutants of concern and may pose a risk in the future to drinking water supplies. Two such compounds are sulfamethoxazole (SMXL) and fluoxetine (FLX). These ionizable compounds are not readily removed from water by conventional water treatment technologies. Powdered activated carbon (PAC) is a useful material for removing contaminants from water and is currently used in many water treatment applications. PACs may carry either a net positive or negative surface charge depending on the pH of solution. This study examined the hypothesis that the …

Evaluating Water Filtration And Disinfection For Household, Using Slow Sand Filters Plus Solar Disinfection, Mariana Demitry

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In this research, a household water treatment system was built and evaluated as a trial for improving the drinking water quality of the Nile River for the low-income communities. The system consisted of household-scale slow sand filters, and transparent polyethylene terephthalate-bottles for solar disinfection. The evaluation of the system depended on the removal/inactivation of some surrogates for the reference pathogens, and turbidity. The reference pathogens are pathogens specified by the World Health Organization to evaluate the efficiency of the household water treatment options. They were chosen to represent the classes of pathogens in water (bacteria, viruses, protozoa). The surrogates used …

Advancing The Implementation Of Hydrologic Models As Web-Based Applications, Prasanna Dahal

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Deeper understanding of relationships between flow in river sand various hydrologic elements such as rainfall, land use, and soil type is imperative to solve water related problems like droughts and floods. Advanced computer models are becoming essential in helping us understand such relationships. However, preparing such models requires huge investment of time and resources, much of which are concentrated on acquisition and curation of data. This work introduces agree and open source web Application (web App) that provides researchers with simplified access to hydrological data and modeling functionality. The web App helps in the creation of both hydrologic models, and …

Journeyman International: Asyv Women's Co-Op & Community Center, Dustin Sullivan

Construction Management

The purpose of this project is to provide a space for the woman of the Agahozo-Shalom Youth Village in Rwanda; to not only learn how to create a self-sufficient community, but also economic and financial independence. The new buildings will provide crucial opportunities for the village on their path of recovery from the Rwandan genocide that occurred in 1994. There will be a total of four new buildings; a storefront, community center, work space, and a building for pineapple and mango prep. The project is headed by the non-profit organization of Empowering Villages, in conjunction with Journeyman International. The project …

Journeyman International: Karambo River Master Plan, Nick Somera

Construction Management

My senior project consisted of an interdisciplinary partnership with students in the College of Architecture & Environmental Design and the non-profit, Journeyman International. My project team has been given the Karambo River Master Plan located in Rwanda, Africa. Empowering Villages, the sponsor for the project, has bought land to make way for new buildings in a fairly remote area with no existing utilities. The site, near the Mahoko village, will foster community, learning, and growing together. There will be a library, classroom, and multi-purpose building constructed for the surround villages in the area. Empowering Villages has also partnered with Afritech …

Journeyman International: Virunga Coffee Co-Op In Rwanda, Africa, Tanner Frikovich

Construction Management

This project-based senior project is an interdisciplinary collaboration between students from the College of Architecture and Environmental Design at Cal Poly San Luis Obispo and a non-profit organization, Journeyman International. The goal of this collaborative effort is to build a coffee cooperative per the request of Empowering Villages, an organization with the mission of empowering rural parts of eastern Africa with socio-economic development solutions. The project will include a community center, restroom, warehouse, and welcome center. The students from the Architecture, Architectural Engineering, and Construction Management programs designed the project and created its associated preconstruction package. The preconstruction package includes …

Journeyman International: Malawi City Cottage, Stefan Denny

Construction Management

This report details the partnership between Journeyman International and City Cottage, to design and construct an educational facility near Lilongwe, Malawi. Journeyman International is a non-profit humanitarian design and construction organization with the mission of connecting top tier CAED students from around the nation to collaborate on philanthropic efforts in the form of senior projects. The proposed project is a 5,800 sqft educational facility built on an institutional land grant; designed to house an auditorium and additional classroom space. The project utilized rammed earth construction methods with steel reinforcement. This report’s focus is on the construction management process of this …

Single-Stage, Venturi-Driven Desalination System, Brandon Proetto

Mechanical & Aerospace Engineering Theses & Dissertations

Water demand is increasing at a rapid pace due to population increase, industrial expansion, and agricultural development. The use of desalination technology to meet the high water demands has increased global online desalination capacity from 47 million m^3/d in 2007 to 92.5 million m^3/d as of June 2017 [49]. Membrane and thermal processes are the two mainstream desalination categories used worldwide for desalination plants. Reverse Osmosis (RO) is the most widely used membrane process and it has become the dominant technology for building desalination plants over recent decades. Thermal distillation, however, has become less and less competitive due to its …

Mitochondrial Mrna Translation Is Required For Maintenance Of Oxidative Capacity, David Lee

Graduate Theses and Dissertations

Oxidative metabolism is required to produce adequate energy to sustain human life. A primary example of deteriorating oxidative capacity is seen in the cardiac musculature during chronic heart failure. This suggests that by improving oxidative potential, chronic heart disease could be mitigated and one approach to accomplish this may be through targeting the mt-mRNA translation system. Purpose: This investigation’s purpose was to characterize disruptions in mt-mRNA translation machinery in multiple forms of cardiomyopathy and to determine if mitochondrial mRNA translation initiation factor (mtIF2) is necessary to maintain oxidative capacity in cardiomyocytes. Methods Using a combination of animal and cell culture …

Development Of A Digital Rain-Sensing Irrigation Pump Controller And An Android Enabled Bluetooth Paddlewheel Flowmeter, Jayendra Mishra

Graduate Theses and Dissertations

For better irrigation efficiency, it is recommended that farmers track their water consumption to avoid over-irrigating. However, it is difficult to implement this as it is labor intensive to supervise pumps manually and available technologies require high investment. Therefore, a rain sensing pump controller for 3-phase electric irrigation pumps and a stand-alone portable Android enabled paddlewheel flowmeter has been developed to test their feasibility.

The pump timer is a retrofit device for irrigation pump panels. The controller allows an irrigator to start and stop the pump with less supervision. An infrared rain sensor is integrated with the controller to measure …

Designing Synthetic Environments To Control Valvular Interstital Cells In Vitro, Kent E. Coombs

Biomedical Sciences ETDs

Aortic valve disease (AVD) is a large contributor to health costs in the United States affecting 2.8% of the population greater than 75 years old. With a growing elderly population due to medical advances, AVD will continue to rise in prevalence over time. Current treatments for AVD are insufficient due to a lack of preventative therapies and the bioprosthetic valves used for surgical replacement have major limitations. Tissue engineered heart valves (TEHVs) present an ideal solution to current AVD needs because of their biocompatibility, capability to integrate with the host’s tissue, and ability to utilize the natural repair mechanisms of …