Letter to a future student Assignment Example | Topics and Well Written Essays - 250 words

Letter to a future student - Assignment Example This was an exciting time to take this course because many of our discussions were about the state of the economy today. The global economic crisis is a very relevant study in macroeconomics. My experience in working on the integrated project was challenging. I had a difficult time communicating exactly what I wanted to say at times. I studied a major international corporation (McDonalds) for my project. I learned how macroeconomic conditions influence the decisions a big corporation has to make. I also clearly could see that large, multinational corporations are major players in a macroeconomic sense once they are firmly established in some nations. If you want to succeed in this class, the best thing you can do is to learn the vocabulary and keep good notes on the different macroeconomic theories. Learn all you can about Keynes and use this as a reference point for comparing the other theories. If you can keep the theories and vocabulary words sorted out, you are going to be successful in this

Computer supported collaborative learning Literature review

Computer supported collaborative learning - Literature review Example The emergence of new technologies in the 21st century is forcing educational institutes to work out new patterns of learning where computers can play vital roles. In order to cope with the modern world requirements Computer Supported Collaborative Learning (CSCL) systems concentrate on refining, facilitating and incorporating the learning process with the support of collaborative partners (Kobbe et al, 2007). CSCL has now become an essential component of the learning environment. CSCL could be defined as a system promising innovations and tools for restructuring teaching-learning processes to prepare students for the emerging knowledge society (Stahl et al, 2006, p409). CSCL has aim to improving the process of teaching and learning through the use of modern communication technology. CSCL is an instructional technology that encourages students to learn together and jointly solve problems. It is the opposite of the traditional concept of learning where learners are solitary receivers of knowledge. CSCL ensures that students are learning in a vigorous, stimulating and socially enriched framework (Nelson and Ketelhut, 2008). CSCL technology focuses on collaborative learning support, to enhance peer interaction and working in groups; to facilitate sharing and distributing knowledge and expertise among community members. CSCL address the issues of concept learning, problem solving and designing (Ioannidou et al., 2010). The system not only functions to communicate ideas and information but also works to impart feedback on problem solving activities. The technology is based on the belief that computer supported systems can effectively work to achieve objectives which may not be possible in face-to-face communication. CSCL concentrates on refining and incorporating the learning process of collaborative partners in a technology-based environment. It allows students to

Evaluating biological methods for treating wastewater

Evaluating biological methods for treating wastewater There are many biological methods for treating wastewater. Among them the most popular processes are suspended growth processes and the boifilm also known as attached growth . Both the above mentioned processes are used to treat wastewater by different mechanisms and variations in their principle of operation for removal of carbonaceous organic matter, nutrients (i.e. nitrogen and phosphorous) and production of biorenewable methane. Attached growth or fixed-film methods are biological treatment based. In these the microorganisms convert the organic substance in wastewater to air and cell tissues are attached to some inert medium. The inert media used in attached growth process is crushed trap rock, limestone granite, wood slats clinkers, , plastic tubes, hard coal materials and corrugated plastic section over which wastewater is distributed. Biological slime layer (i.e., zoogleal slime) develops on contact media as wastewater flows over it. Because of the concentration gradient, all the organic pollutants those are dissolved in wastewater are carried into the slime layer, results in organic oxidation. Removing organic pollutants is done by microorganisms which are present in biological slime film. Rotating biological contactors, Trickling filters, packed bed reactors are the examples for aerobic attached growth process. The examples of anaerobic attached growth are anaerobic packed and fluidized bed reactors. Suspended growth processes are the biological treatment processes in which the microorganisms convert the organic matter, nutrients in wastewater to gases and rotating devices in the liquid will keep the cell tissues in suspension cells tissues. Examples for aerobic suspended growth process treatment are municipal and industrial wastewater. Anaerobic suspended growth processes are used when there is a need to treat high organic concentration industrial wastewaters and organic sludges. Activated sludge process, aerated lagoons, aerobic digestion are the examples for aerobic suspended growth processes and anaerobic digestion and anaerobic contact are the examples for anaerobic suspended growth processes. The schematics of both the attached growth and suspended growth processes for biological treatment of wastewater are shown in Figure 1. The objective of this essay is to compare and contrast both the attached, suspended growth processes for biological treatment of wastewater in terms o f their microbial ecology and review their comparative advantages and disadvantages. In addition, the essay also elaborates and discusses how these processes can be adapted to (a) remove nutrients and (b) produce biorenewable methane from wastewater by emphasising the microbiological principles involved. 2. Comparison and Contrast of Microbial Ecology of Biological Wastewater Treatment The attached growth / Suspended Growth Processes The first basic difference between attached growth and fixed film systems is the relative motion of contact. In attached growth system media is at rest and the sewage flows over it where as in suspended system, sewage and contact media are in relative motion. In attached growth processes, a conservative microbial slime arrangement is considered. The waste water stream is applied on the air-renewable surface. This water stream has minerals and organic substrate. This substance is then metabolized by the Micro organisms in wastewater. This is done in order to increase their population by releasing some energy. In fact, it cannot be considered as an aerobic system, but a device to do aerobic treatment. facultative micro organisms are present in it so it can be considered facultative. They are Pseudomonas, Alcaligenes, Flavobacterium, and Micrococcus. This kind of Aerobic bacteria, like Bacillus, is mostly seen in the upper, aerobic slime surfaces (McKinney 1962). In case when an anaerob ic zone or anoxic is created in thick slime layer, force anaerobe Desulfovibrio and sulfur-reducing bacteria are being removed from slime-medium interface (Rogovskaya M. F. Lazareva 1962). At this case the microbial slime system is know how to grow odours and possibly sloughing takes places because of the production of gases in these interior slimes. Fungi are nothing but aerobic microorganisms existing in the aerobic zone of the slime. These too fester the untreated substrate in wastewater. The effectiveness of fungus is important under relatively low pH situation or with unusual industrial effluents because fungus is useless to bacteria for their food under usual environmental conditions. Algae increasing on the surface of attached microbial slime are usually an unimportant element of the microorganisms population, incomplete to illuminated exteriors and they are clearly liberal to organic substances and high levels of carbon dioxide. Although algae add oxygen to the wastewater, they have been stimulated with responsibility for bed blockage and are considered to be difficult from an operational position (Hawkes 1963). The protozoa are the principally small animals with all shape from the Phytomastigophora to Suctoria are the controlling agents of bacterails population and they cant stable the waste. The free-swimming ciliates present at the slime surface, while the followed ciliates attendance is main in the lower regions of slime. Advanced animals like worms, snails and insect larvae nourish on the lower forms of microorganisms in slime system. They also exist in the higher aerobic areas; can help to keep the bacterial population in a state of high growth or swift food use. Early learning on attached growth populations was intended at the control of the nuisance organisms (filter flies) in dribbling filters by flooding, chlorination and the use of various pesticides. A complete description of the organisms found in close growth system has been presented by Cooke (1959) and the list of a range of organisms can be found from Wang et al. (2009). Attached enlargement processes microbial slime are short term preservation plans that should not act as effective reduction devices for S. typhosa, S. paratyphi, and Mycobacteria tuberculosis and for pathogenic protozoa, such as Entamoeba histolytica (Pierce 1978). For low organic loading, attached growth system does some nitrification since of the presence of Nitrosomonas and Nitrobacter. However, for high organic loading, nitrification in a trickling filter or similar system may be absent or nominal (Shammas Wang 2009). In contrast to the attached growth process, the suspended growth process maintains the microorganisms responsible for treatment within the suspension in flocs. In this process, there are several microorganisms involved to treat wastewater. The suspended growth flocs contain bacterial cells, other microorganisms, inorganic and organic particles. The floc size is 1-1000 mm. Figure 2 illustrates the main microorganisms in the suspended growth microbial community. For the ATP analysis and dehydrogenase activity, the viable cells would account for 5-20% of the total cells. Some authors said that active fraction of bacteria in suspended growth flocs is only 1-3% of total bacteria (Hanel 1988). Suspended growth floc contains prokaryotic and eukaryotic microorganisms, which can be observed with regular phase-contrast microscopy. The major genera in the flocs are Zooglea, Pseudomonas, Flavobacterium, Alcaligenes, Achromobacter, Corynebacterium, Comomonas, Brevibacterium, Acinetobacter, Bacillus spp., as well as filamentous microorganisms. The population of bacteria decrease as the floc size increase results in less oxygen level in the flocs (Hanel, 1988). Anoxic zones can happen within flocs, depending on the accessibility of oxygen attention in the tank and these zones will vanish when the oxygen concentration exceeds 4 mg/L. The internal regions in large flocs favor the growth of anaerobic bacteria such as methanogens or sulfate-reducing bacteria (SRB). Thus, pendant growth system could be a suitable and fitting seed material for starting anaerobic reactors. Gram negative bacteria are main in suspended growth flocs. Hundreds of bacterial damage flourish in suspended growth but only small portion can be spoted by culture-based techniques. Bacteria oxidize the organic substance and change nutrient alteration and produce polymeric materials which aid in the flocculation of microbial biomass. In aerobic pendant enlargement process, the total bacterial counts in order of 108 CFU/mg of sludge. Suspended growth flocs also shelter autotrophic bacteria such as nitrifiers (Nitrosomonas, Nitrobacter), which convert ammonium to nitrate. Phototrophic bacteria such as the purple nonsulfur bacteria (Rhodospirillaceae), green sulfur bacteria are found at much lower levels and they play a minor role in carbonaceous organ ic matter removal in suspended growth processes. The suspended growth system does not usually favour the growth of fungi, although some fungal filaments are observed in suspended growth flocs. The predominant genera found in suspended growth system are Geotrichum, Penicillium, Cephalosporium, Cladosporium, and Alternaria, which grow under specific conditions of low pH, toxicity, and nitrogen-deficient wastes. Protozoa helps in reducing carbonaceous matter, suspended solids, and numbers of bacteria, including pathogens (Curds Hawkes 1983). There is an inverse relationship between the number of protozoa in mixed liquor and the carbonaceous matter and suspended solids concentration in suspended growth effluents. Changes in the protozoan community reflect the food-to-microorganisms (F/M) ratio, nitrification, sludge age, or dissolved oxygen level in the aeration tank. The protozoan species composition of activated sludge indicates the carbonaceous matter removal efficiency of the proce ss. For example, the presence of large numbers of stalked ciliates and rotifers indicate a low carbonaceous matter. The ecological succession of microorganisms in suspended growth treatment system is illustrated in Figure 3. The ciliates (free, creeping, and stalked ciliates) are used for locomotion and for pushing food particles into the mouth, which are most abundant protozoa in suspended growth systems. Stalked, Creeping ciliates ciliates are attached to the flocs. These protozoa move via one or several flagella and take up food via the mouth or via absorption through their cell wall. The role of rotifers in suspended growth system is : They help to remove suspended bacteria, other small particles and contribute to the clarification of wastewater. They are also capable of ingesting Cryptosporidium oocysts in wastewater and thus serve as vectors for the transmission of this parasite. They contribute to floc formation by producing fecal pellets surrounded by mucus. The presence of rotifers at later stages of suspended growth system is because of the fact that these animals display a strong ciliary action that helps in feeding on reduced numbers of suspended bacteria. 3. Advantages and Disadvantages of Attached Growth and Suspended Growth Processes of Biological Wastewater Treatment The advantages of attached growth processes are low maintenance, low energy requirements, and, overall, less technology involved. These assets making them fit for wastewater treatment for small communities, as well as individual homes. In comparison with suspended growth process the main advantages of attached growth processes is simpler operation, no bulking problems, and better recovery from shock loads (Metcalf Eddy 2003). An attached growth process is very effective for biochemical oxygen demand (BOD) removal, nitrification, and denitrification. A disadvantage of attached growth processes are larger area, ineffective in cold weather, and create odor problems. An unprotected attached growth plant is vulnerable to below freezing weather and its recirculation restricted during cold weather. It is less effective in the treatment of higher organic waste. Raw wastewater must be provided to primary treatment to remove the larger solids and floating debris, because these solids can clog the treatment system. The comparative advantages and disadvantages of attached growth and suspended growth processes of wastewater treatment are illustrated in Table 1 and 2, respectively. 4. Nutrient Removal by Attached Growth and Suspended Growth Processes of Biological Wastewater Treatment Nutrients (nitrogen and phosphorous) can be removed from incoming wastewater by biological means in both the attached growth and suspended growth processes. To remove the nitrogen from, we must have to do nitrification followed by de-nitrification. Phosphorous can be removed from wastewater through assimilation of phosphorous in microbial cell. Using nitrifying reactors nitrogen removal can be done in wastewater treatment using attached growth process based trickling. Experiments on nitrifying filters reveal that adsorption, desorption as well as de-nitrification can occur in attached growth bio-film to convert ammonium. At low organic loading the attached growth system does some nitrification because of the presence of bacteria like Nitrosomonas and Nitrobacter but at higher organic loading nitrification in a trickling filter is absent or nominal. The three-stage attached growth process can be used for carbonaceous oxidation, nitrification, and de-nitrification. In case of suspended growth process, the flocs shelter autotrophic bacteria (Nitrosomonas, Nitrobacter), which change ammonium to nitrate. These species occur in clusters and they are in close contact in pending growth flocs and in biofilms. Fungi are also able to do nitrification and denitrification in suspended growth process. Compensation of a fungi-based dealing system are their capability to carry out nitrification in a single step, and they show great confrontation to inhibitory compounds. Molecular methods like aggressive PCR method showed that Nitrosomonas is (an ammonia oxidizing bacterium or AOB) 0.0033% of the total bacterial population and Nitrospira is (a nitrite oxidizing bacterium or NOB) 0.39% for NOB are present in suspended growth system. Features like ammonia/nitrite concentration, oxygen concentration, pH, temperature, BOD5/TKN ratio, and the attendance of toxic chemicals control nitrification kinetics in suspended growth system (Metcalf and Eddy 2003). The growth of a nitrifying population in suspended growth system depends on the surplus rate of the sludge and, consequently, on the BOD load, MLSS, and mean cell preservation time. The growth rate of nitrifiers is inferior in sewage and consequently a long sludge age is essential for the change of ammonia to nitrate. If the age of sludge is more than 4 days, then we be expecting nitrification. There are two processes by which nitrification can be attained in suspended growth reactors: (i) Combined carbon oxidation-nitrification (single-stage nitrification system): this process wokrs at high BOD5/TKN ratio and has a low population of nitrifiers. The oxygen requirement is exerted by heterotrophs (Figure 4). Nitrification must be followed by denitrification to remove nitrogen from wastewater. The rate of denitrification is independent of nitrate concentration but depends on the concentration of biomass and electron donor (e.g., methanol) in wastewater. The schematic of single sludge denitrification system is shown in Figure 6. Some more efficient methods based on suspended growth system to remove nitrogen in wastewater are Bardenpho Process (Figure 7), Sharon-Anammox Process and Completely autotrophic nitrogen removal over nitrite process. Biological phosphorous removal can be done with the basic steps of an anaerobic zone followed by an aerobic zone. During the aerobic stage phosphorus uptake takes and in anaerobic stage it is released subsequently (Manning and Irvine 1985; Meganck and Faup 1988; USEPA 1987). The phosphorus removal processes can be divided into mainstream and side stream processes. The alternating exposure to anaerobic conditions can be accomplished in the main biological treatment process. The most popular phosphorous removal systems based on suspended growth process like A/O Process, Bardenpho Process, and UCT Process are shown in Figure 8-10, respectively. 5. Production of Biorenewable Methane by Attached Growth and Suspended Growth Processes of Biological Wastewater Treatment Several attached growth and suspended growth processes like anaerobic digestion and microbial fuel cell are generally employed to produce biorenewable methane (CH4). A series of microbiological processes will takes place in anaerobic digestion tank to convert organic compounds to methane, carbon dioxide, and reduce the volatile solids by 35 to 60%. Bacteria and methanogens are the responsible species in stabilization of wastewater sludges and for the treatment of industrial and urban wastewaters. Anaerobic digestion produces less amounts of sludge (3-20 times less than aerobic processes). Most of the energy derived from substrate breakdown is found in the final product, CH4. Only 5% is converted into biomass under anaerobic conditions and 50% of organic carbon is converted to biomass under aerobic conditions, whereas. This biogas (mainly CH4) produced from anaerobic digestion contains about 90% of the energy of calorific value of 9000 kcal/m3, and is burned on site to provide heat fo r digesters. Furthermore, synergistic interactions between the various groups of microorganisms are implicated in anaerobic digestion of wastes. The overall reaction can be written as Although some fungi and protozoa (anaerobic protozoa) found in anaerobic digesters, bacteria and methanogens are undoubtedly the dominant microorganisms. Large numbers of facultative anaerobic bacteria (e.g., Bacteroides, Bifidobacterium, Clostridium, Lactobacillus, Streptococcus) are used in the hydrolysis and fermentation of organic compounds. Four types of microorganisms are involved in the transformation of complex materials into simple molecules such as methane and carbon dioxide. The process for methane production through anaerobic digestion is shown in Figure 11. 6. Conclusions The attached growth and suspended growth processes are most widely used for biological treatment of urban wastewater with respective and comparative advantages and disadvantages. The successful design and operation of attached growth and suspended growth processes for biological wastewater treatment require an understanding of microbial ecology of each process, types of microorganisms involved, the specific reactions that they perform, the environmental factors that affect their performance, their nutritional needs, and their reaction kinetics. In contrast to the microbial ecology of the suspended growth processes where the microorganisms responsible for treatment grow in suspension, the active bacteria in attached growth processes cling to some solid surface, natural or manmade, to perform the treatment. It can be inferred that the suspended growth processes are more preferable and advantageous for carbonaceous organic matter removal along with nutrient removal and production of bio renewable methane from urban wastewater in comparison to the attached growth processes.

The Battle At Wounded Knee :: essays papers

The Battle At Wounded Knee On December 15, 1890 authorities feared that the Sioux's new Ghost Dance ³ religion might inspire an uprising. Sitting Bull permitted Grand River people to join the antiwhite Ghost Dance cult and was therefore arrested by troops. In the fracas that followed, he was shot twice in the head. Sitting Bull' followers were apprehended and brought to the U.S Army Camp at Wounded Knee Creek in southwestern South Dakota. Moving among the tipis, soldiers lifted women's dresses and touched their private parts, ripping from them essential cooking and sewing utensils. The men sitting in the council heard the angry shrieks of their wives, mothers, and daughters. Several Lakota, offended by the abusive actions of the cavalry, stubbornly waited to have their weapons taken from them. It was a show of honor in front of their elders, for few of them were old enough to have fought in the "Indian Wars" fifteen years before. That night, everyone was tired out by the hard trip. James Asay, a Pine Ridge trader and whiskey runner, brought a ten-gallon keg of whiskey to the Seventh Cavalry officers. Many of the Indian men were kept up all night by the drunken Cavalry where the soldiers kept asking them how old they were. The soldiers were hoping to discover which of the men had been at the Battle of Little Bighorn where Custer was killed. On the bitterly cold morning of December 29, 1890, Alice Ghost Horse, a thirteen- year old Lakota girl rode her horse through the U.S Army camp looking for her father, one of the Indian men who had been rounded up earlier that day. Less than fifty yards away she could see her father sitting on the ground with other disarmed men from Chief Big Foot's band, surrounded by more than 500 heavily armed soldiers of the Seventh Cavalry. She looked North up the hill where four "guns on wheels" were mounted. Troopers watched silently on each side of the Hotchkiss battery. To one side Alice noticed a familiar figure standing with hands raised above his head, his arms turned upward in prayer. It was the medicine man by the name of Yellow Bird. He stood facing the east, right by the fire pit which was now covered with dirt. He was praying and crying. He was saying to the spotted eagles that he wanted to die instead of his people. He must have sense that something was going to happen. He picked up some dirt from the fire place and threw it up in the air and said, "This is the way I want to go, back to dust. The Battle At Wounded Knee :: essays papers The Battle At Wounded Knee On December 15, 1890 authorities feared that the Sioux's new Ghost Dance ³ religion might inspire an uprising. Sitting Bull permitted Grand River people to join the antiwhite Ghost Dance cult and was therefore arrested by troops. In the fracas that followed, he was shot twice in the head. Sitting Bull' followers were apprehended and brought to the U.S Army Camp at Wounded Knee Creek in southwestern South Dakota. Moving among the tipis, soldiers lifted women's dresses and touched their private parts, ripping from them essential cooking and sewing utensils. The men sitting in the council heard the angry shrieks of their wives, mothers, and daughters. Several Lakota, offended by the abusive actions of the cavalry, stubbornly waited to have their weapons taken from them. It was a show of honor in front of their elders, for few of them were old enough to have fought in the "Indian Wars" fifteen years before. That night, everyone was tired out by the hard trip. James Asay, a Pine Ridge trader and whiskey runner, brought a ten-gallon keg of whiskey to the Seventh Cavalry officers. Many of the Indian men were kept up all night by the drunken Cavalry where the soldiers kept asking them how old they were. The soldiers were hoping to discover which of the men had been at the Battle of Little Bighorn where Custer was killed. On the bitterly cold morning of December 29, 1890, Alice Ghost Horse, a thirteen- year old Lakota girl rode her horse through the U.S Army camp looking for her father, one of the Indian men who had been rounded up earlier that day. Less than fifty yards away she could see her father sitting on the ground with other disarmed men from Chief Big Foot's band, surrounded by more than 500 heavily armed soldiers of the Seventh Cavalry. She looked North up the hill where four "guns on wheels" were mounted. Troopers watched silently on each side of the Hotchkiss battery. To one side Alice noticed a familiar figure standing with hands raised above his head, his arms turned upward in prayer. It was the medicine man by the name of Yellow Bird. He stood facing the east, right by the fire pit which was now covered with dirt. He was praying and crying. He was saying to the spotted eagles that he wanted to die instead of his people. He must have sense that something was going to happen. He picked up some dirt from the fire place and threw it up in the air and said, "This is the way I want to go, back to dust.

Bernini

The Baroque period is emphasized by drama and theatricality. The sculptor Bernie exemplifies this in his works. How does the Coronary chapel exemplify drama and theatricality? Bernie designed every aspect down to the last detail. What do you think of this style? Panoramic view (make it full screen): http:// www. Phantasmagoria. Com/502/Rome/Santa_Maria_Della_Aviators Some details: http:// www. Removable. It/Capped. HTML I really like Bering's style and I appreciate his attention to detail. The Coronary Chapel is very bright on the inside from the virtual tour I took. I like that and I think this is on repose.He wanted an open themed chapel that allows light in because the light signals that this is an open place and that you are welcome to come in. The floor to me is also beautiful and I appreciate the designs he displayed. The focal point is right in the middle and the patterns on the floor are concentric and move out from this point. Also every wall you look at has some sort of pat tern or color. It is a bit clustered but I like it. It is complex and works very well for him. You can spend all day looking at something new and that is the detail I like. Not many places built today have this same detail.Once again with the bright colors it is very welcoming. He draws your attention and wants you to come in and explore. The walls look to be stone and this gives it an earthy feel as well as an elegant flow. It looks to be rich and expensive and the artist did not cut any corners when they made this chapel. I like this and once again the attention for detail is amazing to me. The ceiling is even covered to display their creativity and skill. People come in Just to see the beautiful stone walls and they know that this building was built with the very best materials of this time as well as for today.

Oration piece †Life and works of Rizal Essay

When I was young and innocent, I used to dream of great and wonderful things for the Philippines. I dreamed to see the Philippine flag raised in each and every household, and at the same time singing our national anthem in a blaring voice and a smile on their faces. When I’m old enough to see the real state of our country, these dreams were shattered. I don’t see flags in people’s households but I see households broken. I don’t hear songs but I hear gunshots, cries and remorse. I don’t see smiles but marks of poverty. This was not the Philippines I was dreaming of. This is not what our national hero wished and died for. We need someone who can bring the change in our country. As Filipinos we need not a leader with wealthy family, or rooms of medals and diplomas. Rizal didn’t show off his achievements because people already know him as someone great. He doesn’t need to play a movie of all His works or achievement because his works spoke for themselves. I do say that we must win our freedom by deserving it, by improving the mind and enhancing the dignity of the individual. Loving what is just, what is good, what is great, even to the point of dying for it. Just like Rizal. Rizal is generous in all his endeavors in various fields science, mathematics, literature and the arts, giving it his all, therefore always emerging in excellence. The very person who should lead our country must be someone who has a heart for excellence. Rizal has great dreams for the Filipinos, and he never, not even once underestimated them. With unwavering trust and conviction, Rizal believes in the abilities of the Filipino people and banks on them for the progress of the Philippines. My fellow young men and women, if we want to establish a better Philippines, we need a real president who embodies the characteristics of Dr. Jose Rizal. Let us always remember that authority without love and sacrifice is definitely self serving . Rizal studied in different schools, some of these are Ateneo Municipal de Manila where he was declared one of the sobresaliente or outstanding, University of Santo Tomas where he switched from law to medicine.