THE DISPERSION AND SELECTIVE FLOCCULATION OF HEMATITE ORE

Iron ore is one of the most important ores in the world. Over the past century, most mining of iron ore has been focused on magnetite (Fe3O4). As the name suggests, magnetite is magnetic in nature and is easily separated from gangue (unwanted) minerals through magnetic separation processes. Unfortunately, the magnetite ore bodies are diminishing. Because of this, there has been a recent drive to pursue technology that can economically separate hematite (Fe2O3) from its gangue minerals as hematite is a much more abundant source of iron. Most hematite ore has a very small liberation size that is frequently less than 25μm. Beneficiation of any ore with this fine of a liberation size requires advanced processing methods and is seldom pursued. A single process, known as selective flocculation and dispersion, has been successfully implemented at a plant scale for the beneficiation of fine liberation size hematite ore. Very little is known about this process as it was discovered by the U.S. Bureau of Mines by accident. The process is driven by water chemistry and surface chemistry modifications that enhance the separation of the hematite from its gangue minerals. This dissertation focuses on the role of water chemistry and process reagents in this hematite beneficiation process. It has been shown that certain ions, including calcium and magnesium, play a significant role in the process. These ions have a significant effect on the surface chemistry as reported by zeta potential studies. It was shown that magnesium ions within the process water have a more significant impact on surface chemistry than calcium ions due to steric hindrance effects at the hematite surface. It has also been shown that polyacrylic acid dispersants, if used in the process, can increase product quality (increase iron content, decrease phosphorus content, decrease silica content) substantially. Water, surface and reagent chemistry experiments were performed at a laboratory, pilot, and full plant scale during the course of this work. Many of the conclusions developed in the laboratory and pilot scale were found to be true at the full plant scale as well. These studies are the first published in history to develop theories of water chemistry and surface chemistry interactions at a full plant scale

Design for Low-Cost Gas Metal Arc Weld-Based Aluminum 3-D Printing

Additive manufacturing, commonly known as 3-D printing, has the potential to change the state of manufacturing across the globe. Parts are made, or printed, layer by layer using only the materials required to form the part, resulting in much less waste than traditional manufacturing methods. Additive manufacturing has been implemented in a wide variety of industries including aerospace, medical, consumer products, and fashion, using metals, ceramics, polymers, composites, and even organic tissues. However, traditional 3-D printing technologies, particularly those used to print metals, can be prohibitively expensive for small enterprises and the average consumer. A low-cost open-source metal 3-D printer has been developed based upon gas metal arc weld (GMAW) technology. Using this technology, substrate release mechanisms have been developed, allowing the user to remove a printed metal part from a metal substrate by hand. The mechanical and microstructural properties of commercially available weld alloys were characterized and used to guide alloy development in 4000 series aluminum-silicon alloys. Wedge casting experiments were performed to screen magnesium, strontium, and titanium boride alloying additions in hypoeutectic aluminum-silicon alloys for their properties and the ease with which they could be printed. Finally, the top performing alloys, which were approximately 11.6% Si modified with strontium and titanium boride were cast, extruded, and drawn into wire. These wires were printed and the mechanical and microstructural properties were compared with those of commercially available alloys. This work resulted in an easier-to-print aluminum-silicon-strontium alloy that exhibited lower porosity, equivalent yield and tensile strengths, yet nearly twice the ductility compared to commercial alloys

Relationships of student gender, personal epistemological beliefs, science self-efficacy, attitude, and subjective norms to intended science class enrollment

Few students of either gender enroll in high school physics courses, but young women are especially underrepresented. A total of 698 freshmen from five Iowa high schools participated in a study in which Fishbein and Ajzen\u27s Theory of Reasoned Action was applied to the study of the attitudes and social support that influence decisions to enroll in high school physics, chemistry, and biology classes. Attitude toward enrollment and social support for enrollment predicted enrollment intent, with gender, academic ability, and self-efficacy explaining a small but significant portion of additional variance. Examination of beliefs underlying attitudes and subjective norms suggests that for physics enrollments to increase, students need to feel that they would be successful if they took a physics class, class activities must be enjoyable for male and female students, and parents and students must be aware of the advantages of taking high school physics

A Case for Weakening Patent Rights

(Excerpt) In Part I, this Article introduces the new and emerging technologies, including the Internet, cloud computing, three-dimensional (“3D”) printing, and synthetic biology, which will bring this radical change. Part II provides an overview of the innovation cycle, including the stages of basic research, inventing and prototyping, product development, marketing, and distribution. It also describes, in detail, how these new technologies are dramatically lowering the costs and risks of all stages in the innovation cycle. Part III considers how lawmakers might adapt patent law to account for the new age of innovation and its lower costs of innovation. This Article explores both the magnitude of the change and the method by which that change should be accomplished; specifically, it analyzes various factors that might affect the magnitude of the change to patent strength, such as nonmonetary incentives to innovate, decreased costs of copying innovations, and concerns about U.S. companies’ competitiveness in a global marketplace. After considering these factors, this Article recommends that lawmakers weaken patents by at least twenty-five to fifty percent. Such a change would not only account for decreased costs of innovation, but also would be large enough for the change to be unequivocally felt and studied. To accomplish this reduction in patent strength this Article explores shortening the patent term, but with the understanding that to do so would be politically difficult. Thus, it recommends dramatically raising patent maintenance and renewal fees for the end portion of patents’ lives. Finally, this Article also briefly explores doctrinal changes that could weaken patents in specific technology sectors and explain why we consider them a second-best option

A Case for Weakening Patent Rights

(Excerpt) In Part I, this Article introduces the new and emerging technologies, including the Internet, cloud computing, three-dimensional (“3D”) printing, and synthetic biology, which will bring this radical change. Part II provides an overview of the innovation cycle, including the stages of basic research, inventing and prototyping, product development, marketing, and distribution. It also describes, in detail, how these new technologies are dramatically lowering the costs and risks of all stages in the innovation cycle. Part III considers how lawmakers might adapt patent law to account for the new age of innovation and its lower costs of innovation. This Article explores both the magnitude of the change and the method by which that change should be accomplished; specifically, it analyzes various factors that might affect the magnitude of the change to patent strength, such as nonmonetary incentives to innovate, decreased costs of copying innovations, and concerns about U.S. companies’ competitiveness in a global marketplace. After considering these factors, this Article recommends that lawmakers weaken patents by at least twenty-five to fifty percent. Such a change would not only account for decreased costs of innovation, but also would be large enough for the change to be unequivocally felt and studied. To accomplish this reduction in patent strength this Article explores shortening the patent term, but with the understanding that to do so would be politically difficult. Thus, it recommends dramatically raising patent maintenance and renewal fees for the end portion of patents’ lives. Finally, this Article also briefly explores doctrinal changes that could weaken patents in specific technology sectors and explain why we consider them a second-best option

Technical solar photovoltaic potential of scaled parking lot canopies: A case study of walmart U.S.A.

Solar photovoltaic (PV) technology can provide sustainable power for the growing global population in cities, but it demands considerable land area. This is a challenge for densely populated cities. However, the stranded assets of non-productive parking lots areas can be converted to solar farms with PV canopies, enabling sustainable electricity generation while preserving their function to park automobiles. This study provides a method for determining the technical and economic potential for converting a national scale retail company’s parking lot area to a solar farm. First, the parking lot area for the company is determined and divided into zones based upon solar flux using virtual maps. Then the potential PV yield in each zone is calculated. A sensitivity analysis is performed on the price per unit power installed, solar energy production as a proxy for conversion efficiency, electricity rates and revenue earned per unit area. To demonstrate this method, analysis of Walmart Supercenters, USA is presented as a case study. The results show solar canopies for parking lot areas are a profitable as well a responsible step in most locations and there is significant potential for sustainable energy deployment in cities by other similar retailers using solar PV canopies

A Case for Weakening Patent Rights

This Article contributes to the patent debate by observing that new and emerging technologies are radically altering the relative costs and benefits of the patent system. Although analysts cannot measure the patent system\u27s numerous absolute costs and benefits, this Article demonstrates that new and emerging technologies are significantly reducing the research, development, and commercialization costs ( innovation costs ) that are used by adherents to the incentive and prospect theories to justify the patent system\u27s existence. All things being equal, if significantly, the relative need for the patent system has decreased and will continue to decrease. Thus, this Article argues that patents should be weakened significantly-by at least twenty-five to fifty percent. To support this claim, this Article takes an interdisciplinary approach out of appreciation for the fact that innovation spans many disciplines: Two of the authors are scientists with extensive expertise in three-dimensional printing, and the remaining author is a law professor who is an expert on patent law. Altogether, this Article offers a thorough catalog of new and emerging technologies and their effects, both general and specific, on innovation costs and the patent system

How Implicit Beliefs Influence Trust Recovery

After a trust violation, some people are quick to forgive, whereas others never trust again. In this report, we identify a key characteristic that moderates trust recovery: implicit beliefs of moral character. Individuals who believe that moral character can change over time (incremental beliefs) are more likely to trust their counterpart following an apology and trustworthy behavior than are individuals who believe that moral character cannot change (entity beliefs). We demonstrate that a simple but powerful message can induce either entity or incremental beliefs about moral character

Free and Open-source Control Software for 3-D Motion and Processing

International audienceRepRap 3-D printers and their derivatives using conventional firmware are limited by: 1) requiring technical knowledge, 2) poor resilience with unreliable hardware, and 3) poor integration in complicated systems. In this paper, a new control system called Franklin, for CNC machines in general and 3-D printers specifically, is presented that enables web-based three dimensional control of additive, subtractive and analytical tools from any Internet connected device. Franklin can be set up and controlled entirely from a web interface; it uses a custom protocol which allows it to continue printing when the connection is temporarily lost, and allows communication with scripts

The Impact of Personal Experience on Behavior: Evidence From Video-Rental Fines

Personal experience matters. In a field setting with longitudinal data, we disentangle the effects of learning new information from the effects of personal experience. We demonstrate that experience with a fine, controlling for the effect of learning new information, significantly boosts future compliance. We also show that experience with a large fine boosts compliance more than experience with a small fine, but that the influence of experience with both large and small fines decays sharply over time