Analysis of the the Canadian International Development Agency Research Paper

Analysis of the the Canadian International Development Agency - Research Paper Example The International Cooperation Ministry of the Federal government, which is currently headquartered in Gatineau, Quebec, oversees the activities of CIDA. Its major objectives are social development including child protection and basic education, economic health of developing countries, sustainability of the environment, and striving for good governance, democracy, and respect of human rights by governments in developing countries. The Agency concentrates most of its bilateral aid in a select group of countries including Haiti and Indonesia. However, this concentration is not inclusive of programs offered by such multilateral bodies like UNDP and UNICEF. It does not also include assistance in fast intervention measures for natural disasters, conflict, and crisis, which are offered all over the world by the Agency’s strong hand of help (Bruneau, 2008). CIDA has made real progress in obtaining results in the arena of international development via collaboration with international, Canadian, and local partners. These results are inclusive of a drop in poverty levels from 1.3 billion in 1990 to 980 million in 2004 (Bruneau, 2008). Other accomplishments are the enrollment of more children in developing countries to primary schools, decline in child mortality, and achievement of Millennium Development Goal by developing countries like Ghana. 2. Organizational Design According to the information systems at the agency, CIDA has 2336 positions, which are, classified (Irwin, 2008). The branch in Africa is the biggest of all the branches with three hundred and eighty five positions in total. It is followed by the Asian branch, which has two hundred and twenty eight positions. After which the branch in the Americas follows with its one hundred and ninety three positions, and finally the branches in the Maghreb, Middle East, and Europe with its one hundred and fifty two positions. The policy branch, which consists of two hundred and thirteen positions, is the Agencyâ₠¬â„¢s largest corporate branch. Two hundred and three positions strong branch then follows it for Canadian Partnership, and then the branch for multilateral programs, which is one hundred and nineteen strong and finally the thirty-eight strong Canada corps. With regard to the branches dealing with a corporate service, the branch of HR and corporate services is the most staffed with three hundred and thirty nine positions. It is then followed in a distant second by the information technology and management branch with one hundred and ninety six positions, then by the branch dealing with communication with one hundred and forty four positions and finally by the Knowledge management and performance branch with its forty one positions. The remainders of the positions, which come up to eighty-five, are inclusive of the offices of the Senior Vice President, Executive Vice President, and President (Irwin, 2008). The distribution of the4 Agency’s positions is as follows. Of the two t housand three hundred and thirty six agencies classified positions, eight hundred and twenty three job positions are clumped against one of twenty-three generic descriptions of work at the agency. Administrative and Program services 1563 Social and economic science services 171 Purchasing, commerce, and audit 113 Executive group 108

Create Your Own School Essay Example for Free

Create Your Own School Essay A public schools’ job is to create a standardized environment for students of the general population; however, public schools don’t always meet the needs of the students. Charter schools exist to meet the needs of the students and are more open to parental involvement and local control over state and bureaucracies’ control. However, â€Å"charter schools may deter some minority, poor, and working families from seeking enrollment by requiring them to complete volunteer hours and failing to provide transportation and free lunches to eligible students† (Schnaiberg 2000). My school I create will take the benefits of public schools and the benefits of charter schools to create an emphasis on individual learning and respect for cultural diversity. My school offers students in preschool through twelfth grade, an extended school day and longer school year, because most of December is off. My secular school is founded on respecting and encouraging other religions thus the school works around religious holidays, creating all secular and religious holidays off days. School is in session September 3rd through June 20th. Students in early childhood education program and kindergarten are in class Monday-Friday 7:30am-12:30 pm. Students in first through fifth are in class Monday-Friday 7:00am-4:45 pm. Students in sixth through eighth are in class Monday-Friday 6:45am-4:45 pm. Students in ninth through twelfth are in class Monday-Friday 6am-12:30 pm. Students in ninth through twelfth grade are required to have a Monday-Friday work experience internship; students under sixteen have an on-campus internship (1-4pm), while students over sixteen have an off-campus internship (1:30-4:30pm). My school’s goals are to have students by the end of twelfth grade be able to understand and comprehend at or near college level. In addition, students will learn three languages (English, Spanish, and another), read music sheets, be able to play a musical instrument or sing, have life skills, and have a knowledge of the diverse world we live in. All students pre school through twelfth grade will learn English composition, math, science, grammar, social sciences, geography, reading, literature, foreign languages, visual/performing arts (music, art, theatre, and dance), cultural diversity, U.S. government/economy, and physical education. Middle school students will learn speech: interpersonal communication, small group communication, argumentation, intercultural communication, public speaking, and forensics/debate. Middle school and high school students will learn required electives: basic life skills, introduction to computers, cultures of the world, nutrition/health/safety/careers, life skills, philosophy/religions/cultural anthropology, and human sexuality/anatomy/physiology. My school’s goals are to have students prepared for college and/or having a job as well as serving in the community. In addition to a work experience internship, high school students are required to take personal electives, which are any additional high school electives taken through the local community college or 30 units of college units though AP, CLEP, Dantes, etc. Middle school students are required to take personal electives, which are any additional middle school electives that are high school level. All students sixth through twelfth are required to complete community service to graduate and achieve units (10 units=20 hrs). Middle school students are required to complete at least sixty hours of community service and high school students are required to complete at least eighty hours of community service to graduate. Middle school students are required 360 units to graduate including personal electives and community service; high school students are required 520 units to graduate including personal electives, work internship, and community service. Summer school is required for middle school and high school students. Students are required at least twenty units. Repertory and accelerated classes available. My school holds a high sta ndard for the teachers as well for the students. Students are expected to behave, strive for excellence, respect others, have a good character, and be willing to learn, while the faculty is expected to do the same. â€Å"Most charter schools do not require their teachers to be certified† (Borsa 1999). However, my school requires all teachers K-5th to hold a Teaching Credential and a Masters Degree and teachers 6th-12th are required to hold a Masters or Doctoral Degree in the area they teach. My school promotes a healthy life style, school uniforms, and parent involvement. Parents are required to pay one fee that covers all school material, lunches, schools uniforms, field trips, and other necessary items. The food at my school, which is free, and healthy, that means no soft drinks, cookies, candy, chips, or any other junk food; all birthdays at school will be celebrated without unhealthy food. Parents are encouraged to eat healthy and show students healthy life styles. Students are required to wear a school uniform, a short-sleeved tee shirt with school logo and black pants/shorts/dress/skirt or for formal attire is long-sleeved shirt and black pants/shorts /dress/skirt. The shirt will have a color to represent a grade: Pre-K: Pink, K: Purple 1st: Blue, 2nd: Turquoise, 3rd: Green, 4th: Light Green, 5th: Yellow, 6th: Orange, 7th: Red, 8th: Maroon, 9th: Brown, 10th: Black, 11th: Gray, and 12th: White. Like the school uniform, backpacks will be in the color of the school uniform and have the students name on it. My school has no state standardized tests, but the use of state standards. Instead students are required to test into each grade through a test that measures their cognitive and behavioral level. The complete cognitive test has twenty-seven essays and 2030 multiple choice/true-false questions, which is two essays and 140 or 150 questions per grade. The cognitive test measures what the student should know by the end of each grade. Students can challenge an exam if they feel the grade or class they are in doesn’t reflect their abilities. In addition, students are required to take a test out exam in each subject. It serves as a measure for student learning, and an evaluation for teachers and parents. This exam is compared to the â€Å"test in exam† and options for tutoring/after school help for struggling students. If student doesn’t score higher than 80 percent on an exam, they won’t be promoted to the next class or grade unless they successfully retake the exam. The exam can be retaken twice before the student must repeat a grade of class. My school doesn’t use the Standard Letter Grade, but gives students the option for it . Instead of standard letter grades, students in K-5 will have a grade of Pass (B- or higher in Standard Letter Grade) or No Pass (C+ or lower in Standard Letter Grade). Then 6-12th grade students will have the option of keeping their grades in Pass/No Pass or having standard letter grades. (Students will be put on Academic Probation if their GPA reaches 2.99 or below.) Behavior, class participation, in-class work for students K-12 will be graded in O=Outstanding, E=Exceeds Expectations, A=Acceptable, P=Passing, N=Needs Improvement. Each week behavior and participation reports are sent home so parents can see how their student’s behavior and participation improves or becomes a problem. Teachers and parents go over the childs portfolio, which includes tests, papers, art, quizzes, and other in-class material each quarter. At the end of the year students evaluate their own work and other’s work in the portfolio. The student, the teacher, other students, and the parent grade the portfolio like pieces of art are evaluated at an art gallery. My school gives students the option of independent study or regular classroom learning in middle school and high school. All preschool through twelfth grade students are put in their cognitive level and in small classrooms of twenty students of less; however, middle school and high school students have the option of regular class or packets. In regular class students participate in in-class assignments, quizzes, and tests; students must earn homework and extra credit. Students must have at least 240 points out of 300 to pass each quarter; otherwise the quarter will be repeated in packets. In a packets class or independent study students come to class participate and take in-class quizzes and tests; however, class work is done in packets. Students must have an A- or higher to move on to the next packet. Packets are allowed to be taken home and are equivalent to one week of regular class in-class work; only Physical Education, Speech, Science Lab, and Visual/Performing Arts are not allowed to be taken in packets. The packets are recommended for students who are ill, on religious holidays, etc., which prevent them from attending class. In addition, all students on holiday (December) have the option of completing packets for credit and completing quizzes and tests online with a proctor; the packet requires an A- or better to move on. Overall, my school focuses on creating an emphasis on individual learning and respect for cultural diversity; however, there are intuitional and individual barriers. Intuitional barriers will arise when parents who aren’t secular will try to implement their beliefs into the curriculum, but this school offers a well-rounded approach to learning not faith-based learning. In addition, problems may arise when parents try to control what the child learns and what they become; parents are encouraged to let their children be good at what they are good at. Small class sizes and indivualized learning can cause problems for students and parents who want a more mainstreamed education. Students may feel it is too hard for them, but this school is meant to be challenging in academics, but not in socializing. Since there will be intuitional and individual barriers, parents and teachers are encouraged to be open and discuss any problems and look for what is in the best interest of the child. My belief is that education should offer students prepare students for life outside of education. I provided a school that offers students an extended school day and longer school year and summer school to keep kids out of trouble and respect religious beliefs. My school has educated students prepared for college and/or having a job as well as serving in the community. In addition, I provided a school that promotes a healthy life style, school uniforms, individual learning, good behavior, options in learning, and parent involvement. The goal of my school is to prepare and educate students to learn and be the best they can be in whatever they are good at. This charter school will create an emphasis on individual learning and respect for cultural diversity and more. Although this charter school will have intuitional and individual barriers, the school will provide more positive learning than a negative one. References Borsa, J., Ahmed, M., Perry, K. (August 1999). Charter School Goverence. Paper presented at the annual meeting of the National Council of Professors of Educational Administration, Jackson Hole, WY. ED 436 856. Schnaiberg, L. (2000). Charter schools: Choice, diversity may be at odds. Education Week, 19(35), 1, 18-20.

Agitation Leaching Theory And Practice Biology Essay

Agitation Leaching Theory And Practice Biology Essay Agitation leaching is a chemical process where in the soil that is to be mixed or slurried is kept in contact for a certain period of time with fluid to be extracted. The metal solubility rate is reduces quite noticeably, and the extraction gets completed on the approach of equilibrium between the metal present in the solution and the metal contained on the surface of the soil is approached Excess metal will not be extracted from the surface of the soil unless the soil is accessed by fresh extraction solution and the contact time increases when the system is at equilibrium. On reaching equilibrium, the soil is separated from the extraction fluid using sedimentation, thickening, or clarification. An agitation vat coupled with a solid-liquid separation vessel (typical processes like clarification or sedimentation) is considered to be a single stage The process of extraction is then generally continued in a separate extraction vat and the clear solution obtained from the extraction process is used to speed up the rate of extraction [1]. Agitation leaching-Practice Cyanide and the Gold Industry Introduction One of the most widely used industrial practices is the cyanidation process in the gold industry. Amount of gold present in ores typically occurs at very low concentrations in ores which generally range from less than 10 gm/tonne. At the low level of the gold concentrations the most predominant method used extensively and one that is cost effective is the aqueous hydrometallurgical extraction processes to extract the gold from its ore. Typical hydrometallurgical gold recovery involves an agitation leaching step where the gold is dissolved in an aqueous medium, followed by the separation of the gold bearing solution from the residues, or adsorption of the gold onto activated carbon. After elution from the activated carbon the gold is further concentrated by electrodeposition or precipitation. Gold is one of the noble metals and is not very much soluble in water. Complexes, like cyanide, is known for stabilizing the gold species in solution, along with an oxidant preferably oxygen thereby dissolving the required amount of gold. The amount of cyanide in solution required for complete dissolution may be typically of very low concentrations such as 350 mg/l which accounts for around 0.035% of 100% sodium cyanide Alternative complexing agents for gold, such as chloride, bromide, thiourea, and thiosulfate form less stable complexes and thus require more aggressive conditions and oxidants to dissolve the gold. These reagents present risks to health and the environment, and are more expensive. This justifies the dominance of cyanide as the primary reagent for the leaching of gold from ores since its introduction in the latter half of the 19th century. Manufacture, Transport and Storage of Cyanide Approximately 1.1 million metric tons of hydrogen cyanide is produced annually worldwide, with approximately 6% used to produce cyanide reagents for the processing of gold. The remaining 94% is used in industrial applications including production of plastics, fire retardants, cosmetics, adhesives pharmaceuticals, food processing and as an anti-caking additive for table and road salts. Cyanide is manufactured and distributed for use in gold mining industries in a variety of physical and chemical forms, including solid briquettes, flake cyanide and liquid cyanide. Sodium cyanide is supplied as either briquettes or liquid, while calcium cyanide is supplied in flake form and also in liquid form. The strength of bulk cyanide reagents vary from 98% for sodium cyanide briquettes, 44-50% for flake calcium cyanide, 28-33% for liquid sodium cyanide and 15-18% for liquid calcium cyanide. The product strength is quoted on a molar basis as either sodium or calcium cyanide. The form of cyanide reagent chosen for use typically depends on availability, distance from the source and cost. Where liquid cyanide is used, it is transported to the mine by tanker truck or rail car and is off-loaded into a storage tank. The truck or rail car may have a single or double walled tank, and the location and design of the discharge equipment varies by vehicle. Solid briquette or flake cyanide is transported to the mine in drums, plastic bags, boxes, returnable bins and ISO-containers. The mine generally designs and constructs the necessary equipment to safely dissolve the solid cyanide in a high-pH solution considering the packaging of the reagent. The pH value of cyanide solutions during dissolution must be maintained above pH 12 to avoid the volatilization of the hazardous hydrogen cyanide (HCN) gas. The resulting cyanide solution is then pumped to a storage tank prior to introduction into the process. The cyanide solution is fed from the storage tank into the metallurgical process stream in proportion to the dry mass of solids in the process stream. The feed rate of cyanide is controlled to maintain an optimum cyanide level as demanded by the metallurgy of the ore being treated. Ore Preparation Preparation of the ore is necessary so that it can be presented to the aqueous cyanide solution in a form that will ensure the optimal economic recovery of the gold. The first step in ore preparation is crushing and grinding, which reduces the particle size of the ore and liberates the gold for recovery. Ore that contains free gold may not yield a sufficiently high recovery by sole use of cyanide leaching, due to a very long dissolution time for large gold particles. Such ore may first be subject to a gravity recovery process to recover the free gold before being subjected to cyanide leaching. Gold bearing ores that contain gold associated with sulphide or carbonaceous minerals require additional treatment, other than size reduction, prior to gold recovery. Gold recovery from sulphide ore is poor because the cyanide preferentially leaches the sulphide minerals rather than the gold, and cyanide is consumed by the formation of thiocyanate. These ores are subject to a concentration processes such as flotation, followed by a secondary process to oxidize the sulphides, thereby limiting their interaction with the cyanide during the gold leach. Carbonaceous minerals adsorb gold once solubilised; oxidizing the ore prior to leaching prevents this. To counter this affect, the leaching process may also be modified by the addition of activated carbon to preferentially adsorb the gold. Leaching with Aqueous Cyanide Solutions When gold is leached in an aqueous cyanide solution it forms a gold-cyanide complex by oxidizing with an oxidant such as dissolved oxygen and cyanide complexation. This complex is very stable and the cyanide required is only slightly in excess of the stoichiometric requirement. However, in practice the amount of cyanide used in leach solutions is dictated by the presence of other cyanide consumers, and the need to increase the rate of leaching to acceptable levels. Typical cyanide concentrations used in practice range from 300 to 500 mg/l (0.03 to 0.05% as NaCN) depending on the mineralogy of the ore. The gold is recovered by means of either heap leaching or agitated pulp leaching. In heap or dump leaching the ore or agglomerated fine ore is stacked in heaps on a pad lined with an impermeable membrane. Cyanide solution is introduced to the heap by sprinklers or a drip irrigation system. The solution percolates through the heap leaching the gold from the ore, and the resultant gold bearing solution is collected on the impermeable membrane and channelled to storage facilities for further processing. Heap leaching is attractive due to the low capital cost involved, but is a slow process and the gold extraction efficiency is a relatively low 50-75%. In a conventional milling and agitated leaching circuit, the ore is milled in semi-autogenously ball or rod mills until it is the consistency of powder. The slurry is conveyed to a series of leach tanks. The slurry is agitated in the leach tanks, either mechanically or by means of air injection, to increase the contact of cyanide and oxygen with the gold and enhance the efficiency of the leach process. The cyanide then dissolves gold from the ore and forms a stable gold-cyanide complex. The use of oxygen or peroxy compounds instead of air as an oxidant increases the leach rate and decreases cyanide consumption, due to the inactivation of some of the cyanide consuming species present in the slurry. The pH of the slurry is raised to pH 10-11 using lime, at the head of the leach circuit to ensure that when cyanide is added, toxic hydrogen cyanide gas is not generated and the cyanide is kept in solution to dissolve the gold. The slurry may also be subject to other preconditioning such as pre-oxidation at the head of the circuit before cyanide is added. Highly activated carbon is used in the dissolved gold recovery process, either by introducing it directly into the CIL (carbon-in-leach) tanks or into separate CIP (carbon-in-pulp) tanks after leaching. The activated carbon adsorbs the dissolved gold from the leach slurry thereby concentrating it onto a smaller mass of solids. The carbon is then separated from the slurry by screening and subjected to further treatment to recover the adsorbed gold. When carbon is not used to adsorb the dissolved gold in the above-mentioned leach slurry, the gold bearing solution must be separated from the solids components utilizing filtration or thickening units. The resultant solution, referred to as pregnant solution, is subjected to further treatment (other than by carbon absorption) to recover the dissolved gold. The waste from which the gold was removed by any means is referred to as residue or tailings material. The residue is either dewatered to recover the solution, treated to neutralize or recover cyanide, or is sent directly to the tailing storage facility. Recovery of Dissolved Gold Gold is recovered from the solution first using either cementation on zinc powder or concentrating the gold using adsorption on activated carbon, followed by elution and concluding with either cementation with zinc or electro winning. For efficient cementation, a clear solution prepared by filtration or counter current decantation is required. The most cost-effective process is to create adsorption of the dissolved gold onto activated carbon, resulting in an easier solid-solid separation based on size. To achieve this; the ore particles must typically be smaller than 100 ÂÂ µm while the carbon particles must be larger than 500 ÂÂ µm. Adsorption is achieved by contacting the activated carbon with the agitated pulp. This can be done while the gold is still being leached with the CIL-process, or following leaching with the CIP-process. The CIL-process offers the advantage of countering the adsorption of gold on carbonaceous or shale ore particles, but is more expensive due to less efficient adsorption, increased gold inventory and increased fouling and abrasion of the carbon. Activated carbon in contact with a pulp containing gold can typically recover more than 99.5% of the gold in the solution in 8 to 24 hours, depending on the reactivity of the carbon, the amount of carbon used and the mixers efficiency. The loaded carbon is then separated from the pulp by screens that are air or hydro dynamically swept, thus preventing blinding by the near sized carbon particles. The pulp residue is then either thickened to separate the cyanide containing solution for recovery/destruction of the cyanide, or sent directly to the tailings storage facility from which the cyanide containing solution is recycled to the leach plant. The gold adsorbed on the activated carbon is recovered from the carbon by elution, typically with a hot caustic aqueous cyanide solution. The carbon is then regenerated and returned to the adsorption circuit while the gold is recovered from the eluate using either zinc cementation or electro winning. If it contains significant amounts of base metals, the gold concentrate is then either calcined or directly smelted and refined to gold bullion that typically contains about 70 90% gold. The bullion is then further refined to 99.99% fineness using smelting, chlorination, and electro-refining. High purity gold is taken directly from activated carbon eluates, using recently developed processes that utilize solvent extraction techniques to produce intensive leaching of gravity concentrates [2]. Agitation leaching-Applications Commonly applied to a wide range of ore types, agitation leaching has been in use for well over 200 years. Leaching is typically performed in steel tanks, and the solids are kept in suspension by air or mechanical agitation. Air agitation in carried out in conical-bottomed leach tanks (Browns or Pachuca tanks) was widely practiced in the early years of cyanidation but has been overtaken in recent times by more efficient mechanical agitation with reduced energy requirements and improved mixing efficiency. Well-designed systems can approach perfectly mixed flow conditions in a single reactor, which help to optimize reaction kinetics and make the most of available leaching equipment. Particle size. The material to be leached is ground to a size that optimizes gold recovery and communition costs. In a few cases, whole ore is being ground to very less particle sizes for optimal processing, either by oxidative pre-treatment and/or leaching. Agitation leaching is rarely applied to material at greater coarse sizes because it becomes increasingly difficult to keep coarse solids in suspension, and abrasion rates increase. Increasingly, agitation leaching is being considered to treat very finely ground materials and, with the advances in ultrafine milling equipment have been ground to lesser particle sizes to liberate gold contained in refractory along with the sulphide mineral matrices prior to processing by agitation leaching and/or oxidative pre-treatment. Slurry density. Leaching is usually performed at slurry densities of between 35%and 50% solids, depending on the solids specific gravity, particle size, and the presence of minerals that affect slurry viscosity (e.g., clays). Mass transport phenomena are maximized at low slurry densities; however, solids retention time in a fixed volume of leaching equipment increases as the density increases. In addition, reagent consumptions are minimized by maximizing slurry density, since optimal concentrations can be achieved at lower dosages, because of the smaller volume of solution per unit mass of material. Modification of pH Alkali, required for slurry pH modification and control, must always be added before cyanide addition to provide protective alkalinity, which prevents excessive loss of cyanide by hydrolysis. Most leaching systems operate between pH 10 and 11. Staged addition of alkali may be required throughout the leaching circuit to maintain the desired operating pH, particularly when treating ores containing alkali-consuming materials. pH control is achieved by manual or automatic (on-line) measurement at various stages in the process. Calcium hydroxide (slaked lime, Ca (OH),), or sodium hydroxide can be used for pH modification. Calcium hydroxide (slaked lime) is the cheaper of the two but is less soluble and produces solutions that are much more susceptible to salt precipitation and scale formation. Unslaked lime (CaO) is used occasionally because it is less costly than slaked lime, but it is less effective for pH modification. For nonacidic- or non-alkali-consuming ores, calcium hydroxide concentrations of 0.15 to 0.25 g/L are typically required to achieve the desired pH range for leaching (i.e., pH 10 to 11). This represents typical lime consumptions of 0.15 to 0.5 kg/tonne for non-acidic ores. Sodium hydroxide is known to be more effective than calcium hydroxide at dissolving a variety of minerals, particularly at high alkalinities, and it is a highly effective dispersant. This may result in the dissolution of ore constituents, such as silicates, to produce various solution species, which can subsequently precipitate in a number of undesirable forms, potentially affecting downstream processes, including filtration, gold precipitation, or carbon adsorption. Consequently, calcium hydroxide is generally the preferred method of pH control in agitated leaching systems. Cyanide Cyanide may be added to agitated leaching systems either prior to the leaching circuit, that is, during grinding, or in the first stage of leaching. Subsequent reagent additions can be made into later stages of leaching to maintain or boost cyanide concentrations to maximize gold dissolution. In the absence of cyanide-consuming minerals in the ore or concentrate to be leached, cyanide concentrations used in practice range from 0.05 to 0.5 g/L NaCN, and typically between 0.15 to 0.30 g/L NaCN. Typical cyanide consumptions observed in agitated leaching systems for free-milling ores vary from about 0.25 to 0.75 kg/t. In cases where the feed material contains significant amounts of cyanide consumers and/or high silver content (i.e., >20 g/tonne), higher cyanide concentrations may be applied, that is, 2 to 10 g/L NaCN. In such cases, cyanide consumptions may vary from 1 to 2 kg/t, and in some cases much higher, depending on the nature and amount of cyanide-consuming minerals. Cyanide conc entrations are usually monitored by manual titration techniques or less commonly by on-line cyanide analyzers, based on titrimetric, colorimetric, potentiometric, and ion-specific electrode techniques. Oxygen Content Oxygen is typically introduced into leaching systems as air, either sparged into tanks as the primary method of agitation, or supplied purely for aeration. In either case, crude sparging systems are usually sufficient to provide satisfactory bubble dispersion and to ensure that adequate dissolved oxygen concentrations are maintained. Typically, the amount of dissolved oxygen concentrations can be maintained at, or even slightly above, calculated saturation levels with air sparging. The optimum sparging system depends on the geometry of the leach tanks. For example, conical-bottomed Pachuca tanks with single sparging points (common South African practice prior to about 1980) and flat-bottomed leach tanks with multiple sparging points, or simple down-the-agitator-shaft addition, have all been used. In a few cases, particularly when treating ores that contain oxygen-consuming minerals, pure oxygen [5] or hydrogen peroxide [4] have been added to increase dissolved oxygen concentrations a bove those attainable with simple air sparging systems. Residence time. Residence time requirements vary depending on the leaching characteristics of the material treated and must be determined by test work. Leaching times applied in practice vary from a few hours to several days. Leaching is usually performed in 4 to 10 stages, with the individual stage volume and number of stages dependent on the slurry flow rate, required residence time, and efficiency of mixing equipment used. Counter-current leaching. Leaching efficiency can be enhanced by the application of Le Chateliers principle. In summary, the lower the concentration of gold in solution, the greater the driving force for gold dissolution to occur, although in a mass transport controlled reaction it is debatable what role this plays in gold leaching. An alternative explanation for this phenomenon is the reversible adsorption of gold cyanide onto the ore constituents. The gold adsorption is reversed when the solution is exchanged for a lower grade solution or when a material (such as activated carbon or suitable ion exchange resin) is introduced into the slurry, which actively competes for the Aurum cyanide species. This effect can be exploited in practice by performing intermediate solid-liquid separation steps during leaching to remove high-grade gold solutions, and rediluting the solids in the remaining slurry with lower-grade leach solution and/or with freshwater plus reagents. Successful applications of this principle have been used at the Pinson and Chimney Creek, Nevada (United States), and East Driefontein (South Africa) plants, and at other operations [6, 7]. At many operating gold plants, an increase in gold extraction is observed when a leach slurry can be transferred from one type of process equipment to another (i.e., between leach tanks, thickeners, filters, pumps, and pipelines).This can be explained by the different mixing mechanisms in the different equipment, coupled with other factors, such as changes in slurry percent solids, changes in solution composition, and the effects of pumping transfer (i.e., plug flow mixing).Likewise, the benefits of the carbon-in-leach (CIL) process compared with leaching and carbon-in-pulp (CIP) have been clearly demonstrated both experimentally and in practice, even without the presence of interfering constituents in the ore[8]. The CIL process results in improved conditions for gold dissolution[3].

Punks :: essays research papers

Punks Did you know that the first commercially successful punk band was the Sex Pistols? Then came groups like Black Flag, Husker Du, and Bad Brains. Punk was invented in Britain in the mid Seventies. The first American punk started in a New York club called CBGB's. CBGB's would attract a crowd of about 500 with its Sunday-afternoon hard-core matinees. The concerts would be over by a reasonable time so kids could get home to eat dinner with their parents. In this paper we will take a look at some history and aspects of punk rock over the years. Slam dancing has been popular through the history of punk. You may have heard of called "mashing" or "stage diving." Mashing is just a big game of bumper cars like you played when you were a kid. I think Natalie Jacobson who is dating the lead singer of "Murphy's Law" describes stage diving best when says, "It's like diving into a human carpet. Something like the old kids' trust game. Just my way of getting into it. Gospel people got their thing, I got mine."1 Some punks consider themselves Nazis', or are concerned with issues like peace, racism, and nuclear war. Most punk is against parental, musical, and political authorities. On the other hand some isn't. Bob Mould of Husker Du talks about politics quite frequently in his songs. Most punks that live in small towns have trouble making friends. They find it hard to relate to most people. Sixteen- year-old Becca Levine finds it hard to make friends in her small town. She comes from a family of divorced parents that never have understood her. Her mother thinks it's just a phase she's going through. As Becca Quotes, "Parents around here treat me like I'm kind of weird."3 She has met someone from New York City that understands her. She meets with him at concerts at clubs like the Ritz or CBGB's. She met someone else also.

Latin America colonial times Essay

?4. How does colonialism engage with notions of spirituality, witchcraft, and/or (ritual) intoxication? You may analyze how the distinctions between orthodox and unorthodox practices were distinguished (and oftentimes blurred). You may look at Staden, the readings on witchcraft and â€Å"superstition,† etc. Beginning in 1492 when the Spanish under the crown of Castile invaded the Americas, where their first settlement was in Santo Domingo, their main motivations were trade and the spread of the Catholic faith through indigenous conversions and economic gain. Due to these objectives they intervened and attempted to change every facet of the indigenous way of life including their ‘notions of spirituality, witchcraft, and intoxication’. The indigenous population had formally been removed from the jurisdiction of the inquisition by order of King Phillip the second in 1571, however the native people of Mexico and other invaded lands of the Americas were still prosecuted on accounts of witchcraft or being Nauatil (witches). Colonialism engaged with notions of spirituality and witchcraft by asserting their dominance in attempts to completely annihilate these practices. They attempted to make sense of what they did not understand by attributing these happenings to witchcraft and condemning those prosecuted as witches. Further, as previously mentioned, they attempted to spread the Catholic religion by deeming the religious practices previously ‘inherited’ (treatise on Heathen superstition) by the indigenous population as acts of witchcraft. In his letter to Reverend Don Francisco Manso de Zunga, Hernando Ruiz de Alarcon a Spanish navigator of the sixteenth centaury wrote that the reasons behind attempting to completely eradicate the superstitious ways of the people he regarded as Indians was that some of their practices such as â€Å"drunkenness was not permitted to them even in their heathen state† and was punishable by death. (39) His reasons behind â€Å"scraping of drunkenness from the memory of humanity† (39) is that even to those who are believed to be Pagans or non believers (heathens) (39) it was prohibited, therefore once baptised and accepted as Christians it is was a sin to indulge in these acts. To increase the spread and conversion to Catholicism within the Indians, Alarcon, validates the eradication of their customs. Further in his letter Hernando Ruiz de Alarcon explains how by indulging in these superstition practices the Indians are harming themselves. He states â€Å"This (their drunkenness) is the cause of the total destruction of the health of their bodies, and consequently the sufficient and principal barrier to their preservation and increase† (39). Alarcon explains that the deepness with which these practices have fastened into the native American culture leads him to believe that â€Å"the ministers have entered late into their parishioners’ language. † (40). Here we get an indication that despite their conversion to Christianity, Alarcon believes there is no hope to change the Indians’ superstitious ways. In light of the Spaniards determination to spread the Christian faith they attempted to eradicate all other religious practices within the Americas. In his letter Alarcon states in his letter â€Å"others (superstitions) have a weak foundation, because a traditions of their false gods is hardly found among their stories† (39). He explains their previous religion had no concrete roots, they worshiped ‘false gods’ and it was illegitimate; therefore, all rituals and practices for this cause were superstitious. It is important for us to note that the work of finding and documenting the acts of superstition in Mexico was bestowed on Alarcon and therefore it was in his best interest to exaggerate the evidence he supposedly finds. Further, he admits that he is not fully capable to undertake this task because of his â€Å"defective intellect and small experience with writing† (40). In his Treatise on the Heathen Superstition Alarcon explores many aspects of the Mexican native population’s way of idolizing their god’s or goddesses, he attributes this act to an act of worshiping the devil. This is another example of how the Spanish used the notion of witchcraft to propel the spread of Christianity. In his treatise Alarcon states â€Å"and by this means they usually communicate with the devil, because he usually communicates with them when they are deprived of judgement with the said drink and deceives them with different appearances† (48). In this example we can see how Alarcon uses Christianity and the threat of the devil to abolish drunkenness. Alarcon also uses the Devil to explain phenomenons that were beyond the scope of the Spanish understanding. He states in his treatise, â€Å"they (the sages in Mexico) are always deceitful and ceremoniatic and seek to persuade people that they are consummate in knowledge, since they profess to know what is absent and to foresee what is in the future, which, it may be, is revealed to them by the Devil, who can, through knowledge and conjecture, foresee many future events. † (45). Due to the fact that Alarcon and other Spaniards at that time could not make sense of why the prophecies or futuristic readings of the native Mexican sages were holding true, they declared it an act of the Devil and therefore a form of witchcraft. Another example of the Spaniards condemning the unexplainable acts in the Americas is in the document â€Å"On her Deathbed, Maria de la Candelaria Accuses Michaela de Molina of Casting Spells† produced in Guatemala in 1696. In this text different testimonies of various people that witnessed the sickness of Maria de la Candelaria a girl servant. In the testimony of Dona Juana Gonzalez a Spanish woman and mistress of Maria, she states, â€Å"the reason that she presumes this (that Michaela de Molina had casted spells on Maria) is because her servant, Maria had some fights with [Michaela] and not with anyone else. † (170) The Spaniards and even the natives of Guatemala could not fathom why or how Maria was dispelling such large amounts of blood and various objects like stones, rags and hair from her mouth and nose therefore attempted to reason it by condemning Michaela in the act of witchcraft. It is important to understand why the Spanish were interested in Maria’s sickness. In Spain and other parts of Europe the acts of witchcraft were highly condemned. People were afraid of loosing their power and therefore they feared the unknown. They condemned it by illegalizing all forms of witchcraft. Further, the act of ‘drunkenness’ and other practices not coherent with the beliefs of Christianity were also attributed to witchcraft therefore abolishing witchcraft became a means to spread the Christian faith specially since the indigenous population had formally been removed from the jurisdiction of the inquisition by order of King Phillip the second in 1571.

Abraham Darby and the Iron Revolution

Abraham Darby and the Iron Revolution Englishmen Abraham Darby  (1678 - 1717) invented coke smelting in 1709 and, advanced the mass production of brass and iron goods. Coke smelting replaced charcoal with coal in metal foundries during the process of refining metals; this was important to Britains future since charcoal at that time was becoming scarce and was more expensive. Sand Casting Abraham Darby scientifically studied brass production and was able to make advances in that industry that turned Great Britain into an important brass goods exporter. Darby founded the worlds first metallurgy laboratory at his Baptist Mills Brass Works factory, where he refined brass making. He developed the process of sand molding that allowed iron and brass goods to be mass produced at a lower cost per unit. Before Abraham Darby, brass and iron goods had to be individually cast. His process made the production of cast iron and brass goods a continuous process. Darby received a patent for his sand casting in 1708. Greater Detail Darby combined the existing technologies of casting iron with casting brass that produced goods of a greater intricacy, thinness, smoothness, and detail. This proved important to the steam engine industry that came later, Darbys casting methods made the production of the iron and brass steam engines possible. The Darby Lineage Decedents of Abraham Darby also made contributions to the iron industry. Darbys son Abraham Darby II (1711- 1763) improved the quality of coke smelted pig iron for forging into wrought iron. Darbys grandson Abraham Darby III (1750 - 1791) constructed the worlds first iron bridge, over the Severn river at Coalbrookdale, Shropshire in 1779.