Classroom Observation Essay Example | Topics and Well Written Essays - 1000 words

Classroom Observation - Essay Example According to Vygotsky and Cole (1978), teachers can use both levels of Vygotsky’s proximal development zone information to organize classroom activities in involving instructions, cooperative learning activities and scaffolding. Instructions can be planned in order to provide adequate practice in the proximal development zone for groups of children or to individual children. Cooperative learning activities can be organized with children’s groups at levels that are different so that they can help one another learn. Scaffolding is a tactic for assisting the child in her or his proximal development zone whereby the adult gives prompts and hints at various levels. Here, the task is not simplified by the adult rather; the learner’s role is effectively simplified through graduated teacher intervention. According to Vygotsky & Cole (1978), the Vygotsky theory suggests that children learn best whenever the material is new in the Zone of Proximal Development (ZPD). This m eans that the material is not too easy but, a bit challenging which ultimately with a little assistance from an individual who is more learned, the material can be mastered and then shift the zone upwards. In the Math connect program class; the teacher tried to ensure that the class understood the various basic tests that they were required to perform. The teacher effectively used three methods, which are instructions, cooperative learning and scaffolding to teach the Math lesson. The teacher started by doing examples with the class as a whole and gradually advanced to higher levels in the Zone of Proximal Development. This was done by the teacher in various ways. The teacher did a number of tests and then individual tasks were assigned to the class on individual levels. The teacher used various symbols to do the examples which is an example of TPE 1A. The teacher asked the children to write the test, and he would go round the class checking on the answers individually. This was an example of TPE4. Some of the math addition examples that the teacher gave the students include: 1. Round both 22 and 39 to the nearest ten. 22 rounds to ___ 39 rounds to ____ Then, add the rounded numbers to estimate the sum, therefore the sum of the rounded numbers is ___ 2. 700 – 500 = ____ The teacher was able to assist the children individual by explaining how the questions were supposed to be done in order to arrive at the right answer. Here the teacher was using TPE 6B. Those children, who were not able to get the answer correctly, got the opportunity to be taught on an individual level. This assistance was particularly much helpful to each child since they got the chance to be explained individually where they did not understand. After going around the class, the teacher divided the class into groups of three’s and questions were given to the groups to tackle. The children here were able to discuss in groups in answering the questions. The teacher then went round in the various groups checking on their progress and answering any

Happening Truth Essay Example for Free

Happening Truth Essay I was wearing white, sparkly Skechers and those pants that swoosh together every time you take a step. Fourth grade was a tough year as my class moved to Proctor Elementary school and hit my awkward stage. I was taller than all my friends and my chubby cheeks overwhelmed my face. My self confidence was very low being fairly heavy for my age, I felt as if I had not excelled at anything so far. Gym class was my least favorite class because I was slower than most of the class and the year started with a dreaded test. Sit-ups, push-ups, pull-ups, and the timed mile were in my very near future. After I made it through that week we played games and I most significantly remember playing soccer hockey. After Mrs. Magner chose the teams it was up to us 10 year-olds to choose positions. I had my back turned to him when he said it. Rachel should be goalie because she is so fat! he yelled to the class. I felt my face overcome with hotness and my heart seemed to fall into my stomach. I turned to the rest of the class and looked down at the floor but still felt their eyes on my growing body. My eyes began to water but I still took my position in the net. On the bus ride home I saw people whispering about the days events and when I got off the bus I broke down. My mom tried to comfort me with compliments but I knew those were just things she had to say. School the next day was terrifying for me and when I opened my lunch the Yodels were replaced with carrots and dip. It is hard to believe that I was so affected by this event that seems ridiculous to some. I dont hold a grudge against the boy who humiliated me that day but I am actually grateful for the experience. Today I am confident in class and I enjoy going to school with my peers. I am comfortable with my body and dont feel self conscious because I know there are more important things than a simple body type. From that day I learned that others opinions should not affect your personal outlook on life. My sister is in fifth grade and is going through the same stage I experienced so I do my best to relay what I have learned so she never needs to fear school or classmates. As a high school junior, I believe I have grasped this concept by becoming involved and improving the outlook I have on myself. Self confidence is so important coming into high school and throughout life so not one person, or minute comment like the one I heard, should interfere with that.

Air pollution control residues

Air pollution control residues INTRODUCTION Description of Overall Problem Air Pollution Control (APC) residues are the solid output of the flue gas treatment equipment installed on incinerators (this report refers specifically to APC Residues from incinerators handling Municipal Solid Waste MSW). They comprise the fly ash from incineration (middle and fine grades) together with the reagents (mainly lime and activated carbon) used in the flue gas treatment. Thus, they contain: Volatile contaminants from the original waste (inc chlorides, metals), Compounds created in the incineration process (inc dioxins), Further materials from the flue-gas treatment process (sulphates, together with high alkalinity). Therefore they are classified as hazardous waste. Approximately 170,000t/y (Technology Strategy Board 2009) of such residues are produced in the UK 3-4% of the total waste mass incinerated (Environment Agency, 2002). This tonnage is growing as more waste is incinerated to generate electricity and heat, and to reduce landfill. While increased energy recovery and reduced landfill are worthwhile in themselves, achieving them has created the problem of the hazardous APC residues. In the UK the prevalent destination for these residues has been landfill, but this option is under threat from tightening landfill Waste Acceptance Criteria, and rising landfill taxes, so new solutions are required. There are various treatment/recovery options available for APC residues. However these raise other concerns, primarily: Financial and energy cost of treatment Generation of further effluent Environmental impact of the treated waste Quality control of the recovered materials. Objectives and Scope The overall goal is to identify cost-effective management options for APC residues, within Waste Acceptance Criteria. The ultimate objectives of implementing such options are shown in Requirements (Appendix 1). For this study, the specific the objectives are: Briefly analyse the shortcomings of the existing methods of treatment and disposal of APC residue in landfills, along with the barriers in the UK for re-use of APC residues in various industries, such as cement aggregate, asphalt and ceramics. Propose energy- and cost-effective methods for the treatment of APC residue which reduce the leachability and amount of heavy metal/dioxins present. Also suggest a supplier of technology for each treatment method proposed. Compare the cost per tonne for each option, including treatment and disposal costs (including current and future landfill taxes), based on the hazardous classification of any remaining waste. Suggest potential re-use opportunities for materials recovered from the treatment process, indicating potential markets and revenues. The scope is focused on APC residues from municipal waste incineration. It is assumed that current incineration technology and operating conditions apply, with waste of current composition, resulting in residues of current composition. The objectives have been pursued in the context of current UK and EU regulation. This is explained in terms of the waste management hierarchy in table 1. Notes of Figure 1: Further processing leading to recovery may be in or outside the system boundary depending on whether the process is likely to be dedicated to this application. In either case the resulting wastestreams are inside the system boundary Landfill operations are outside the system boundary, but the long term leaching behaviour of all landfill waste will be considered, even if it meets WAC. Report structure This report has been structured to give an overall review of the management options for the Air Pollution Control residue, intended to provide a details of the findings related with work aiming to give recommendations on its treatment. Chapter 1. Background and scope. Chapter 2. Introduction to the residues, overview of major management strategies, legislative aspects, and environmental issues Chapter 3. Details on the residue treatment techniques, operation principles, and development status Chapter 4. Appraisal on the recovery and utilization techniques, operation principles, and development status. Chapter 5. Overview of status for available solutions, documentation level, assessment approach for environmental impacts, outline of important aspects for consideration, qualitative and quantitative comparison of each treatment processes. Chapter 6. Recommendations System Engineering Management Plan (SEMP) is listed in Appendix 2. This is an outline of system requirements and mechanisms for verifying whether the requirements are met. It will provide an overview to integrate different technical elements of the project. The plan will also describe the activities, processes and tools used to ensure an achievement of the project outcomes to the client and other stakeholders. Press Release is placed in Appendix 3 and this would form a basis of a publicity campaign for the project. MANAGEMENT AND REGULATORY FRAMEWORK FOR APC RESIDUE APC residues generation and characteristics APC residues come from the cleaning process of the gaseous emissions, which are produced during the incineration. Dry and semi-dry scrubber systems are used in the cleaning process and involve the injection of an alkaline material to remove acid gases, particulates and flue gas condensation (Sabbas et al. 2003). Finally, fabric filters in baghouses are used, where the fine particulates, i.e. the APC residues are focalized and removed from the gaseous emissions (Sabbas et al. 2003). It is estimated that APC residues represent 2-5% of the original waste on a wet basis and their production in the UK is approximately 128,000 tonnes per annum (Amutha Rani et al., 2008). In general, APC residues from municipal solid waste incineration (MSWI) consist of fly ash, carbon and lime and contain dioxins and furans (Amutha Rani et al., 2008). They are highly alkaline materials (pH 12.0-12.6) and they comprise significant concentration of heavy metals, salts and micro-pollutants (Sabbas et al. 2003 ). Depending on the initial waste composition, the incinerator and the air pollution control system, their composition may vary significantly (Amutha Rani et al., 2008). The typical range of APC residues composition is shown in table 2. The APC residues are characterized as hazardous wastes (190107*, according to the EWC) due to their chemical content and their impact on the environment, primarily by leaching. Regulatory Framework Introduction Regulations and legislation on waste management in the UK have evolved considerably over the years as a result of identification of new pollutants, public health and environmental concerns, economics and technological advancement (Pocklington, 1997 and McDougall et al, 2001). This assertion suggests that legislation and regulations play a major role in ensuring sustainable waste management. In addition, the establishment of legislation on waste management shows the radically changing perception of humans and communities towards the environmental impact of human activities (Pocklington, 1997). Today, regulations and legislation provide a framework for efficient handling of hazardous wastes such as APC residue. Amutha Rani et al (2008) observed that sustainable management of APC residues depend on the implementation of UK and EU waste management legislation. The Existing regulatory and legislative framework for managing APC residues in the UK About 80% of the environmental legislation in the UK have their origins in the European Commission laws (Pocklington, 1997). The existing legislative and regulatory framework for APC waste management in the UK and EU include: Waste Incineration Directive Integrated Pollution Control Directive Landfill Directive and ensuing waste acceptance criteria/procedure EA guidance on the classification of hazardous waste Water Framework Directive However, the discussion on the regulatory and legislative framework for this project focuses mainly on the UK Landfill directive and EA guidance on classification of hazardous wastes. These subjects are pertinent within the boundary of this project more so as Landfill disposal is common in the UK. Also IPPC directive is discussed briefly to highlight the roles public participation and deployment of best available techniques in meeting our objectives. The key objectives of these legislation and regulation are to: Reduce the amount of APC residue generated and improving the quality of exhaust gas (McDougall et al, 2001) Reduce the amount of APC going to Landfill (EA Guidance on landfill, 2006) Prevent environmental impact (ESA 2004) Reduce the risk of human harm (US National Research Council 2000, ESA 2004) This diagram illustrates the relationships between the established regulatory framework and stages in the APC management process. There is no specific legislation covering recovery or reclassification of APC residue in the UK (ESA 2004). Quina et al (2008) also points out that legislation for recycling APC has not yet been established in the UK. The Integrated Pollution Control Directive: Directive 2008/1/EC concerning integrated pollution prevention and control This Directive aims at establishing means to prevent or reduce emissions into air, water and land (IPPC, 2008). Hence this directive is crucial as it suggests various methods of incineration and treatment that could reduce the impact of APC residues on the environment during incineration, treatment or landfill. The IPPC Directive is based on four principles namely: Best Available Technique (BAT) Integrated waste management Flexibility Public participation The BAT refers to the most effective methods of operation that would reduce environmental impact and enhance results such as making residues from incineration less hazardous. In the BAT, optimizing resources and harnessing or saving energy are prioritized (Gargulas N. and Mentzis A, 2007). Also, the BAT is flexible and no terms are imposed since it recognizes that different conditions apply in different cases. The Best Available Techniques Reference (BREF) is a reference document on technical input needed to determine the BAT to be adopted. This BREF contains technical information on available means of treating APC residues such as sintering, vitrification, stabilization and solidification. This project has considered the BATs to APC treatment and these methods are discussed in chapter 3. However, there are no BATs available for landfills. Notwithstanding, Landfill operators and APC treatment plants require permits issued by the Environment Agency with public support to ensure that t here are no health or environmental impacts as a result of their activities (Macleod C. et al 2006 and IPPC 2008). The role of the public is crucial in this directive. Article 15 of the Directive, gives the public full privileges to participate in decision making processes leading to the issuance of permits for installation of plants, and for carrying out technical and administrative changes. This aspect is very important especially in the proper project planning and execution (see SEMP). Therefore the installations of APC treatment facilities and the method involved are tailored to meet public requirements as well as legislative requirements. All hazards inherent in operating APC treatment facilities shall be made known to the public in accordance to this directive. Also the outcome of compliance tests on treatment facilities with regard to environmental impact shall be made public (IPPC 2008). Thus, it can be argued that since the public are key stakeholders in this project, good public perception is needed in accordance with the IPPC directive to ensure sustainable management of APC residues. Environment Agency guidance on classification of hazardous waste The essence of this guidance is to distinguish different kinds of wastes based on their physical and chemical properties which include their toxicity or hazardous nature. The Hazardous Waste Directive (HWD), council directive 91/689/EC and the Revised European Waste Catalogue (EWC) form the regulatory framework for this guidance. The HWD aims at defining hazardous wastes to ensure the correct management and regulation of such waste (EA Hazardous Waste 2008, pg 5). This directive identifies 14 hazardous properties of wastes, thus hazardous wastes are classified H1 H14 according to their hazardous properties (EA, Hazardous waste 2008). The EWC code is derived from the industry and process producing the waste, and the type of waste (EA hazardous waste 2008). APC residues are categorized as hazardous wastes with absolute entry (Rani et al 2008 and ESA 2004). Under the European Waste Catalogue (EWC), APC residues fall under the category of wastes from incinerators (waste management facilities) that have a generic code 19. The specific code for solid wastes generated from gas treatment such as APC residues is 19 01 07. Wastes resulting from the treatment of the APC residues such as the partially stabilized APC residue, the vitrified material etc are also categorized as hazardous with absolute entry (EA hazardous waste 2008). However, when tests confirm that the constituents of treated waste have become less or non hazardous, they can be reclassified as hazardous wastes with mirror entry or non-hazardous as the case may be(EA Hazardous waste 2008). Solidified and partly stabilized wastes are coded 19 03 06 and 19 06 04 respectively with absolute entries, while vitrified wastes from flue gas treatment are assigned the code 19 04 02. The Landfill Directive 1999/31/EC of 26 April 1999 on the landfill of waste The primary objectives of the landfill directive are: To reduce waste going to landfill the prevent or minimize environmental impact as a result of waste disposal Stringent measures and standards have been set to reduce the burden and reliance on landfill (EA guidance on landfill, 2006). Landfills are classified into three categories: non-hazardous, inert and hazardous landfills (Landfill (England and Wales) Regulations, 2002) For APC residues, a key requirement in the Directive prior to landfill is to perform tests to determine its long term and short term leaching behaviour and to carry out treatment to reduce its toxicity (EA guidance on landfill, 2006). This project suggests that the need for treatment of APC residues augments the case for exploring potentials for recovery or reclassification of the residues. Article 6 c (iii) of the Directive reflects our aim to make APC residues at least stable non-reactive hazardous wastes (SNRHW) or completely non-hazardous through efficient treatment techniques such as vitrification, washing, stabilization and plasma technology. SNRHW are known to have low leaching potentials (EA guidance on landfill, 2006). Treated APC residues with leaching behaviour equivalent to those of non-hazardous waste can be disposed at designated non-hazardous landfill subject to meeting the relevant waste acceptance criteria (EA guidance on landfill, 2006 and Landfill (England and Wales) Regulation, 2002). APC residues must meet the waste acceptance criteria (WAC) for a designated landfill after treatment. Schedule 1 of the Landfill (England and Wales) (Amendment) Regulation 2004, stipulates the procedure and criteria for disposing or accepting waste at landfills. Waste Acceptance Criteria and Procedure The WAC is elaborately designed to deal with the technical requirement of wastes such as APC residues designated for landfills in the UK (England and Wales). It also aims at controlling the disposal of wastes into landfill which is a common practice in the UK. Technically, the WAC ensures that the numerical leaching characteristics of APC residue are determined prior to disposal at landfill (EA Guidance on Landfill 2006). Thus, after their mandatory treatment, APC residues must meet the relevant waste acceptance criteria before they are accepted into landfill. The leaching characteristics include: the elements and compounds in APC residue and their leaching properties (in mg/kg or L/S) and the hazardous nature of the APC residue (EA Guidance on Landfill, 2006). The Environment agency is responsible towards ensuring that the criteria for particular landfills are met. Preceding the WAC is the Waste acceptance procedure. The Waste acceptance procedure for APC requires basic characterization, compliance testing and on-site verification (EA Guidance on Landfill 2006). The basic characterization is done to determine the physical and chemical characteristics of the waste (EA Guidance on Landfill 2006). Incineration plants are responsible for carrying out the basic characterization of the APC residues since they produce the APC while the landfill operator ensures that compliance testing and on-site verification are done (EA Guidance 2006). Approved tests are defined in schedule1 part 2 of the landfill regulation 2004 and they include tests for determining treated APC composition and leaching behaviour. The compliance tests are carried out to verify if leaching limit levels predicted in the basic characterization are credible. Besides exploring opportunities for reuse of APC residues and recovery of valuable materials from the residues, this project also aims to treat APC residues to meet at least the waste acceptance criteria for SNRHW to enable disposal at a non-hazardous landfill. Amendment 14 of the Landfill (England and Wales) regulation 2004 states the criteria for disposing SNRHW in the non-hazardous landfill. Discussions There is no specific legislation on the reuse of wastes such as the APC residues in the UK. Notwithstanding, the UK without incineration network (www.ukwin.org.uk) tagged the use of fly ash and APC residues for construction works as irresponsible. Thus it can be suggested that re-use is implied in this clause as well. However, if it is well proven that APC residues can be managed sustainably without any long or short term environmental repercussions, it will pave way for debates to strengthen the existing regulatory frame and also re-focus the views of environmental activists toward the prospects in the residues. ESA report (2004) argues the provision of regulatory certainty by the government is necessary in enhancing investment towards sustainable management of APC residues. The report also suggests that investments will focus on reliable APC treatment technologies. There are several scientific developments for managing APC residues pioneered by waste management companies such as Techtronic in the UK. Environmental problems and management strategies Most of the APC residues (around 88%) (Environmental Agency, 2002) produced in the UK, are disposed of into landfills. During their disposal or any kind of utilization or handling, a number of environmental impacts can be caused. Dust and Gas emissions Dust emissions are represented as a potential risk, due to the size of the APC residues particles (0.001-1 mm) (Sabbas et al., 2003). Despite the easily dispersion of these fine particles, a survey by the Environmental Agency at a number of landfill sites in the UK testifies that their concentrations are within the recommended air quality objectives (Environmental Agency, 2002). Gas production is another potential environmental impact related to the disposal of APC residues. Gas is produced by metallic aluminum hydration (Sabbas et al., 2003) and because of that, some explosions have been reported (Sabbas et al., 2003). However, the production of gas is significantly lower compared to the production of the municipal solid waste landfills, due to their low biodegradable content of the APC residues. Leaching production The major environmental impact is the leaching production of APC residues The leaching behaviour of the elements present in APC residues is the main source of environmental concern. Leachates can cause pollution of soil, groundwater and surface water bodies. The leaching behavior of the APC residues is very complex and depends on a lot of parameters. The pH and the liquid to solid (L/S) ratio of the residues that will occur in the landfill site are important factors which affect determine their leaching behaviorbehaviour as well as the availability of the elements which are contained in the APC residues. The pH depends on the characteristics of the leaching fluid and the waste, i.e. APC residues, and is the key factor of many elements leachability. Leaching of most major elements (e.g. Al, Ca, S, Mg) and heavy metals (e.g. Cd, Pb, Zn) are strongly pH-dependent (Astrup et al., 2006). This dependency of the pH causes a significant difficulty on the prediction of the leaching behaviorbehaviour. Generally, APC residues carry on their pH in alkaline values for a long time (many thousands of years) (Astrup et al., 2006). However, their pH decreases as the time passes and the APC residues are washed by the infiltrating water (the neutralize capacity decreases) (Astrup et al., 2006). Thus, the prediction of the landfills pH and thereby the leaching behaviorbehaviour of the residues in over a long term period is complex. The L/S ratio represents the amount of the leachate that comes in contact with a given amount of APC residues (Sabbas et al. 2003 pp what page?) and depends on the characteristics of the APC residues and the climatic conditions, the hydrology and the hydrogeology of the area (Sabbas et al. 2003). Usually, as the time of disposal passes the value of the L/S ratio becomes higher for a particular application site. Due to this contact the properties of the waste as well as the leaching behaviorbehaviour of the waste change. Thus, the value of this ratio is a very important parameter for the leachate content. The availability for leaching is a parameter, which characterizes the particular waste and represents a fraction of the total content of contaminants in the waste itself (Sabbas et al. 2003). The typical values of the availability for the APC residues are shown in table 2 and they can provide a theoretical estimation of the maximum release of a contaminant in a period of 1000 to 10000 years (Sabbas et al. 2003). The prediction of the leaching behaviour and the evaluation of the environmental impact of APC residues are based on leaching tests. Leaching values for the APC residues arising from leaching test are summarized in table 4. The first leachate from APC residues is usually characterized from soluble salts (e.g. chlorides, hydroxides of calcium, sodium and potassium) and trace element such as Pb and Mo (Sabbas et al., 2003). Contrary to the high solubility of this elements, the solubility of toxic organic compounds is believed to be not high due to their hydrophobic nature and their low concentration in APC residues (from properly operated MSWI plants) (Sabbas et al., 2003). Long term leachate concentrations are usually lower than the initial or they may remain atto the same level. The only exceptions are the elements Al and Zn, which concentrations in the leachate are increase d inover a long term period (Astrup et al., 2006). As it is explained above the leaching behaviour of the APC residues depends on the environmental conditions and changes during the time of the disposal. Thus, an analytical prediction of the long term leaching behaviour is very difficult and it should be based on a combination of information on leaching principles, leaching tests, field measurements, simulation of mineral changes and speciation (Sabbas et al., 2003 page number pls). Due to the complexity of the long term leaching behaviour, the data available in literature are limited. Management of APC residues In the UK the disposal of any waste to landfill is regulated (see regulations section). Generally, the landfills are classified as suitable for hazardous, non-hazardous or inter wastes and, for each of these types of landfill, particular leaching limit values (Waste acceptance criteria, WAC) are defined and should be achieved for any waste are to be landfilled. Table 5 shows the leaching limit values (WAC) for the three types of landfill sites and if they are compared with the values in table 4, it becomes obvious that APC residues cannot be landfilled without a prior treatment. And non-hazardous waste deposited in the same cell. Either TOC or LOI must be used for hazardous wastes. UK PAH limit values are under development. Following the recent consultation exercise the UK Govt may review the limit values in tow years time (2006). If an inert waste does not meet the SO4 at L/S 10 limit, alternative limit values of 1500 mg/l SO4 at C2 (initial eluate from the percolation test) prEN 14,405 and 6000 mg/kg SO4 at L/S10 (either from percolation test or bach test BS EN 12457-3), can be used to demonstrate compliance with the acceptance criteria for inert wastes. The values for TDS can be used instead of the values for Cl and SO4. Or DOC at pH 7.5-8.0 and L/S 10 can be determined on pr EN 14429 (pH dependent test) eluates. Disposal to landfill (Amutha Rani et al., 2008) APC residues are mixed with wastewater to form a solidified product. During this treatment the residues react with the CO2 from the atmosphere reducing the pH to values between 8 and 9. This mixing also eliminates the dispersion of the APC residues particles. After this treatment, the APC residues reach the WAC and they are landfilled into monofill cells at a hazardous waste landfill. This process is used by a treatment plant in GloucesstershireGloucestershire, from which most of the APC residues treated by this method in the UK are coming. Storage in salt mines In this disposal method the APC residues are loaded in sealed capsules and pitted 170m below the surface (Amutha Rani et al., 2008). The disposal in salt mines can take place for a long term. They are characterized as well isolated, very dry, with stable atmosphere and natural gas-impermeable salt layers (Clement, 2000). Salt mine for this purpose is located in Cheshire, England, where a major percentage of the APC residues, produced in the UK, are stored (Amutha Rani et al., 2008). Use in waste acid treatment (Amutha Rani et al., 2008) Due to the mixing of waste acid (usually HCl) and APC residues, the lime content of the APC residues is convertedsed into less hazardous components (CaCl2) and the concentrations of Zn and Pb are reduced. Furthermore, the pH is at high levels, preventing the salts release. Thus, the final mixture from this process is non-hazardous and it is described as sludge from a physico/chemical treatment; it is classified as EWC code 190206 and can be disposed of in non-hazardous landfills. TREATMENT TECHNIQUES Ash Washing Process Description: The objective of Ash washing process is to extract a number of minerals from the APC residue obtained after Municipal Solid Waste incineration and thereby diminish the leachability of various compounds remaining in the residue. The process also aims to improve the quality of the residue obtained for further re-use applications or to reduce the overall content of waste going to the landfill. According to Quina et al (2001), ash washing, acid leaching, electro-chemical process and thermal treatment are some of the most widely used methods for extracting metal values from the APC residues. The separation techniques studied in this section are ash washing with MgSO4, bioleaching using Asphergillus niger fungi and leaching using extracting agents. Each process has different prerequisites, operation time and cost, objectives and risks associated with them. Ash Washing With MgSO4: Chimenos et al (2005) The process aims to apply the optimum parameters for washing APC residue by utilising minimum energy and water. This process uses multi-stage washing process to diminish the leaching of chloride and sulphate salts present in APC residue and thereby ensuring that the amount of harmful substance present in wastewater is reduced. The wastewater produced is recycled and re-used in the process using employing a rapid spray evaporation technique which runs on the waste heat produced from pumps, turbines and incineration furnace. Figure 3a showsrepresent the overall process diagram of operation. The research conducted by Zhang et al (2008) shows that the leachability of the heavy metals and chlorides present in APC residue depends on its pH level. The pH of the solution, when MgSO4 is added during the washing process, may be controlled by the formation of gypsum as shown in Eq(1). Ca(OH)2 + MgSO4 CaSO4 + Mg(OH)2..(1) Bioleaching Q.Wang et al (2009) This process is considered to be a biohydrometallurgical approach to extract heavy metals from APC residue. It is considered to be a green technology because of it makes use of the natural ability of microorganisms to break down solid compounds into soluble and extractable form by enzymatic oxidation or reduction. The process uses the acids secreted by Aspergillus niger fungi such as oxalic acid, citric acid and gluconic acids to extract the heavy metals present. Water-washing was is used as a pre-treatment before the bioleaching process to reduce the bio-leaching period from 30 to 20 days and to extract the maximum amount of chloride and sulphate salts. Figure 4 shows an overall process diagram for the bioleaching process. Bioleaching is a low cost and low energy consumption approach. Leaching Using Extracting Agents Fedje et al (2010) This process uses leaching agents other than water for extracting heavy metals like Zn and Pb. The efficiency of the extraction agent depends on heavy metals of interest, the concentration of the extracting solution, the pH and the liquid/Solid ratio used. The goal of the process is obtain a solution in which the concentrations are high enough to enable further separation or recovery. The leaching media used for this process are 3M HNO3 L/S = 5 0.1 M EDTA with pH adjustment L/S = 5 3M NH4NO3 L/S = 5 The choice of these leaching media was based on their ability to form a complex with metal ions. Table 6 compares the efficiency of the aforementioned leaching agent in extracting the heavy metals from APC residue. Figure 5 represents the overall process diagram. The most widespread leaching method used for APC residues is acidic leaching using strong mineral acids such as HCl and H2SO4. However, due to the high alkalinity of APC residues, large amounts of acids are needed which results in trouble with storage and handling. Moreover, the reaction of APC resid

To Kill A Mockingbird by Harper Lee - Answers :: To Kill a Mockingbird Essays

To Kill A Mockingbird by Harper Lee Question : On giving Jem and Scout air rifles, Atticus tells them that to kill a mockingbird is a sin. Miss Maudie explains that mockingbirds only do one thing, and that is to sing their hearts out for us. Who are the mockingbirds in the story, and how have they been ‘killed’ by the society around them? Ideas : The two main mockingbirds are Boo Radley and Tom Robinson, but there are others within the storyline. Boo Radley has been shut away from the world by his father and then later his brother through an incident which occurred fifteen years earlier when he stabbed his father with a pair of scissors. The suggestion is that he had gone mad and should have been committed to an asylum. His influence in our story is all-good in that he gives gifts to the children, repairs Jem’s pants when they are caught on the fence and, of course, saves the children’s lives when Bob Ewell attacks them. Sheriff Tate recognizes the vulnerability of Boo and that any publicity would destroy him, so he says that the death was an accident. Tom Robinson is actually killed and his death is a sin committed by the whole white community of Maycomb. All he tried to do was to abide by the rules of the society in which he lived and when a black person is asked to do a chore he obeys. The main enemies of birds are cats and Lee describes Mayella as being like ‘a steady-eyed cat with a twitchy tale’ and the bird she is focusing on is of course, Tom Robinson. Lee’s description is that of a cat stalking its prey. Jem to some degree was also a mockingbird. He went with Scout to the black church in order to please Calpurnia, and the Rev. Sykes. Jem suffers in that his youthful idealism is shattered by the verdict given by the all-white jury at the trial. The pet-dog of Maycomb is called Tim Johnson, a bird-dog, who one day acts strangely because he has caught rabies. He gave pleasure to the townsfolk, but suddenly he now causes fear. So much so that even the mockingbirds are silent. Atticus shoots the dog for the good of the whole town. Question : Discrimination rears its ugly head in many forms within this story. Give examples of this. Ideas : The obvious discrimination is that of the dominant white community over the subservient black community. They are not given the same opportunities regarding education, illustrated by the visit to the Negro church where only a few can read.

Agriculture and the Nitrogen Cycle Essay

Agriculture is an important industry that provides food for human consumption. The decrease of land available for agriculture coupled with the increase of human population has required that agricultural lands increase their output. This was achieved through the use of improved crop varieties, more productive livestock, better weed and pest control and the increased use of fertilizers, specifically nitrogen fertilizers which has linearly increased to 1. 2 Mt in the 1980s. However, farming also affects the environment. Increases in phosphorus and nitrate contents of water lead to increased biological activity and large concentrations of nitrate in drinking water create health hazards. J. K. R. Gasser studied the nitrogen cycles in agriculture and reported the results in his article â€Å"Agricultural Productivity and the Nitrogen Cycle. † Gasser (1982) explained that nitrogen is emitted from the soil or from animal effluents as ammonia, nitrous oxide or N2. Considerable amounts of nitrogen are also recycled directly as animal urine and feces. The preceding crops in agricultural lands also affect the amount of nitrogen released for the current crops. However, Gasser (1982) explained that no arable system provides enough nitrogen for the maximum production of crops such that additional nitrogen must be added in the form of fertilizers. Gasser (1982) reported that there is no evidence supporting that the increased use of nitrogen fertilizer also increases the total amount of nitrogen in soil-plant system. He stated that little of the nitrogen in circulation â€Å"will appear directly in the atmosphere or groundwaters, most will leave the agricultural system after one or more changes or subsidiary cycles† (Gasser, 1982, 313). Gasser (1982) concluded that the losses from the system must be at least as large as the known inputs. He persuaded to quantify the movement of nitrogen, the understanding of which would allow the losses from agricultural system to be minimized improving the utilization of nitrogen in farming and reducing its effects on the atmosphere and water. Reference Gasser, J. K. R. (1982). Agricultural productivity and the nitrogen cycle. Philosophical Transactions of the Royal Society B (Biological Science) vol. 296, no. 1082, 303-314.

Cultural Differences in Business Essay

I have read a lot about the cultural differences between Asia and the United States. I have talked to some of my Asian acquaintances here in Okinawa. There are quite a few cultural differences in the business worlds in Hong Kong and the States. In the states, employees have stronger feelings about and opinions of the intrinsic contracts of a business. The employees’ inner images come into play with these feelings because they feel that if they have a good and strong inner image then the outer image will automatically be a good one. They feel that extrinsic contracts are not as important, but still an issue when it comes to business. Employees in the United States are not as respectful to management and will even argue if they feel they have a strong point. In some cases this may be a good thing. In the United States we tend to be more aggressive and have strong opinions rather than suggestions. In Hong Kong, they believe that extrinsic contracts are everything. They believe as long as they have a strong front and image then there business will succeed. This is a good thing when it comes to public images because if you look like you have a strong business then the public will not know any different. Intrinsic contracts are not a main concern in Hong Kong. They are pushed to the side until they have a strong front and then it may be worked on.

Essay Sample on Criminal Law and Procedure

Essay Sample on Criminal Law and Procedure Criminal law and procedure essay: In recent years, criminal procedure place the weight of evidence for the prosecution, meaning it is the work of the prosecution side to attest that the defendant is accountable over any rational uncertainty. This is in contrast to having the defendant attest that he/she is blameless, and all uncertainties determined in support of the defendant. The law also permits the defendant the freedom to legal advocate and any defendant who cannot afford a lawyer provided with one by the government. The common rule in law commands that crucial prove is acceptable unless the law recommends otherwise. Hearsay and rumors not considered as evidence unless the defendant admits of uttering the words claimed against him. Any information attained unlawfully to be used as evident was dismissed to be termed as valid evidence in a court of law. The authority to prohibit unlawful evidence in Australia is entirely under the common law and on statutory requirements. Its trite law that in criminal proceeding of all jurisdiction that a person is innocent till proven guilty. The burden of proof of all criminal cases lies on the prosecution. The proposed amendments to the Uniform Evidence Act of 1995 are to the effect that, in cases where a person is accused of offences against the person or property, and such person had a number of three previous convictions of similar offences, such evidence of conviction may be adduced in court against the person. In my opinion if such an amendment is allowed, it would automatically result to a miscarriage of justice in the courts of Australia. Such an amendment also seriously undermines the principle of presumption of innocence and creates suspicion as to the innocence of the accused, as noted in the case of Perry v R 1982 44 ALR. In 1982 the defendant was tried and convicted of attempting to murder her husband by poison. The prosecution evidence against the defendant was that; not only did her husband suffer arsenic and lead poisoning while living with her, and that she was a beneficiary of an insurance policy on her late husband, there were three other people had also died over the past eighteen years, residing together with Ms. Perry, from a result ingesting harmful substances. The defendant was convicted and upon Appeal the Australian High Court squashed the conviction on the grounds that the deaths of the three other people should not have been allowed in court. Evidence of previous convictions is among the types of evidence that are not admissible in a criminal trial in Australia. These kinds of evidence are not admissible, not because there is proof that the evidence being adduced is faulty or amounts it to a falsehood; but for different reasons depending on the situation. A good example is hearsay and rumors not considered as evidence unless the defendant admits of uttering the words claimed against him. Illegally obtained evidence is also another example of evidence not admissible in a court in South Whales and it’s environs The authority to prohibit unlawful evidence in Australia is entirely under the common law and on statutory requirements.3 Opinions of persons not deemed to be experts in a particular field are not admissible as evidence in any Australian court. Further, there is privileged evidence, for example information shared between a lawyer and his client, or that between a priest and a penitent during confession, which is not admissible in a court of law on account of it being privileged. Confessions that are made under duress are also not admissible in a court of law. There is also a category of evidence that the court finds admissible without much qualification. This includes direct evidence, which is mainly based on the witness’ personal observation which if it is true, proves a certain fact given by either team. Circumstantial evidence is evidence that gives an inference that a particular fact exist. Corroborating evidence is also another class of evidence readily admissible. Its main purpose is to strengthen initial evidence submitted. Demonstrative evidence is any physical exhibit that can be examined by the jury, while forensic evidence is evidence gathered and studied with the help of science and other specialized methods. The proposed amendment to the evidence act, amounts to what the law terms as prejudicial evidence. These are the kind whose prejudicial effect would over lap its probative value, which by the rule in the case of R v Christie (1904) AC 545 is not admissible. A criminal trial entails serious offences against the state, and when the accused is facing the court of law, the trial is majorly characterized by the presence of a jury. The defendant is presented with the circumstance of the case in hand and is asked to take a plea to the extent that he agree or disagrees with the charges as read to him. If he agrees to the claims the judge immediately gives a verdict in accordance with the law but if the accused denies he is guilty a case trial then begins. The prosecutor begins by addressing the jury stating clearly the case in hand against the defendant. Witnesses are then cross-examined by both the prosecutor and the defendant’s representative. When all proof has been represented in the court room the prosecutor and the defendant side presents their final arguments to the court room and precisely to the jury, the judge then offers clearance of how the law applies to the evidence and the case as a whole. The jury is then provided with some privacy, to discuss at length the matter in hand so that substantial verdict can be made. If the jury finds the accused not guilty, the person left free, however if found guilty then the judge with a task of giving sentence to the accused who then becomes a prisoner. It is clear that the work of the jury is to examine the factual points of the case and their correctness, while the judge focuses on the points of law. Statutory law provides for rules of collecting of evidence in criminal trial and the procedure to be taken. In case of points that are in contention in a criminal trial, a lawful procedure must be followed by both parties where one party provides evidence to influence the court in his/her favor. The law establishes strategies used to ensure that the evidence offered in court can be termed as truthful. Statutory law controls the use of proof whether written or oral and demonstrations in court proceedings as evidence to the case presented. The common law provides for judicial diplomacy in cases where the evidence provided is not valid enough or is irrelevant section 137 of the common law was expected to give a realistic means of not including expert outlook evidence of indefinite dependability, nevertheless this has not been so, because section 137 of the uniform evidence law states that; â€Å"In a criminal proceeding, the court must refuse to admit evidence adduced by the prosecutor if its probative value is outweighed by the danger of unfair prejudice to the defendant† The suggested amendments being allowed on the onset of trial shift the mindset of the jury, as they assume the guilt and not the innocence of the accused person. Therefore the whole process is then geared towards proving that the accused person is innocent of the alleged crimes, putting the burden on the defence. This would totally distort whatever pillars of ensuring absolute deliverance of justice our fore-fathers put in place and consequently amounting to the accused person being denied the right to a fair trial, a right entrenched in our constitution. The other reason that for not allowing previous conviction as evidence is that, the jury may be tempted to assume that the way a person behaves in the past, creates a pattern of his behaviour and that they are more likely to act in the same manner. Also, the jury may use this evidence to proof mens rea of the accused person. Clearly, this by inference would mean that bad character evidence is now admissible in the court of law. In the case of Perry v R 1982 44 ALR Murphy J states that, â€Å"common conjecture about improbability of series of events are often wrong†. He goes further to state that if the accused is associated with a sequence of deaths, injuries or losses, a jury may too readily infer that the association is unlikely to be innocent; an assumption that could be wrong under a particular circumstances. Another rationale for excluding evidence of previous conviction is that, as fate would have it, the facts of the other instances of misconduct may cause a jury to be biased against the accused person. The case of R v Bond (1906) 2 KB 389 Kennedy J noted that once the evidence of previous convictions was admitted it would require herculean efforts by the jury of the time to regard the accused person as other than a person of depraved character whose uncorroborated evidence, whether or not he was guilty, could not be acted upon except where supported the prosecution case. However, in law, there are exceptions to every rule. The evidence act provides that it is Legitimate for the crown to there is legitimate for the Crown to adduce similar fact evidence against the accused and if that accused chooses to testify, then it is also legitimate for the Crown to cross examine that accused about that similar fact evidence. The types of questions are required leave of court. Conclusion In accordance to the proposed reforms, to be made in criminal law and procedure the propositions presented are in agreement with what has been in existence for years. In presenting evidence in a court of law, various rules have to be considered, and the law has to be followed to the core. Both parties have to be conversant with the requirements of the law concerning the matter in hand. For instance, evidence provided must be relevant and non-offensive to the defendant. Maintenance of the evidence must also be followed to the core in case a trial case is expected to take longer. The evidence must not be tampered with, and high security has to be provided to the evidence presented. Expert evidence must conform to the common law requirements to ensure the jury presented with the necessary evident and not being confused by the expert, to alter with their judgment. Trial judges are sometimes victims of a specialist who try to confuse the judges’ assessment and the judge is therefore required by the law not to confuse the jury when analyzing the expert analysis of the case in hand. Secondary authority also plays a significant part in ensuring the criminal law and procedure process of presenting evidence conforms to the rule of law. Therefore, the amendments to be made on criminal law and procedure about the evidence subject should be carried out as the law tries to protect the defendant until proven guilty beyond reasonable doubt. If special care is not taken, and the amendments approved, it would lead to the erosion of the principle of presumption of inno cence and thus harming innocent citizens which is more dangerous that failing to punish particular criminals. It would lead to conviction of innocent accused persons who did not commit the alleged crimes, which counters the measure of criminal justice system, one which whose aim is to secure convictions of the guilty in order to facilitate their rehabilitation process.. These results to a pervasion of justice, one in which in this case would have been allowed by a commission for reforms whose main purpose are to be custodians of justice. One way to ensure the above scenario is avoided would be to not allow for the proposed reforms to go through. Perhaps the agenda should be to tight the noose of justice to ensure that rules of evidence and the letter of the law is adhered to in order to avoid situations where intentions of a certain law are not fulfilled.