THE USE AND ABUSE OF HISTORIC PRECEDENT Research Paper

THE USE AND ABUSE OF HISTORIC PRECEDENT - Research Paper Example Some of the stylistic architectural designs applied mostly in Los Angeles include but not limited to the Ancient Egypt and Japanese architecture. These styles were rampant in the olden days but as time went by, different architectures resolved into reinterpreting them into the modern ways of constructing buildings. This paper will seek to explore how stylistic period in architectural history namely Ancient Egypt and Japanese architecture has been reinterpreted in the buildings found in contemporary Los Angeles. In presenting the reinterpretation, MarYella Hotel, Roman Gardens, Church of Christ Scientist and The Getty Center buildings will be used as as a clear illustration of transformation to modern buildings in Los Angeles. The history of the period and structure of Ancient Egypt The Ancient Egypt was an architectural style used by architects to design buildings, which came to be very influential sites during and after civilization. Studies show that the Ancient Egypt style of cons truction started and ended in the years between 3050 BC and 900 BC (Nicholson and Ian 45). During this time, architects managed to develop a large and vast array of monuments that ended up being very great, famous, and influential to an extent that the following generations carried the knowledge with them. This style of architecture had a number of characteristics among those who involved themselves with it. First, the architects used two predominant materials during the construction of almost every building, which were stone and sun-baked mud bricks respectively (Roseman 51). Prospects have come to put across that, architects applied the Ancient Egypt construction style mainly because there was advent scarcity of wood. During and after the so-called Old Kingdom, architects had an obligation to reserve stone for building temples and tombs whereas use bricks in building fortresses, royal palaces, and walls of towns as well as temple precincts. In some instances, ancient Egyptians pre ferred using the Ancient Egypt style of constructions in erecting buildings due to the presence of hot and dry climate that preserved brick structures for a long time. Thus, one could point out that some of the reasons why the Egyptians resolved to build buildings using bricks, which was a major component of construction materials during the Ancient Egypt, include the prevailing climatic conditions. This is clearly illustrated in MarYella Hotel Architecture. Additionally, Roseman argues that the Ancient Egypt stylistic method of construction served as a way of aligning events astronomically (58). For example, the ancient architects who applied this style in building temples ended up recording certain events such as the equinoxes and solstices, which later provided people with the measurement and time when such an event took place. To some extent, this style had some religious significance, which appears to have been presided over by the Pharaoh himself with reference to ceremonials that signified their opening. The Japanese architecture The Japanese architecture is indeed very complex and according to architectural analysts, it had many characteristics. Traditionally, the Japanese architectural style of construction was typified by structures made of wood, slightly elevated off the ground, and thatched with roofs or tiles. Further, Roseman evidences that structures made using the

The Role of Religion in the United States and Egypt Essay

The Role of Religion in the United States and Egypt - Essay Example US Puritan ancestors believed that men were born evil but had the potential to be good, through self-control and self-motivation. The Protestant religion teaches that self-discipline and hard work contribute to the "godliness† of individuals (Chapter 9), which is reflected in the beliefs about human nature, and in the attitude towards work. Similarly, the Islamic belief proclaims hard work as a cherished virtue (Chapter 10). Muslims believe that people are born good and develop into positive directions (Chapter 10). The Americans view time as a key resource (Chapter 9). Their present efforts and resources are oriented to the future. Unlike the US, the time has different dimensions in Egypt; it is not a linear adherence to schedules and deadlines, but rather an abstract mixture of people and transactions (Chapter 10). The equality in the United States is proclaimed by Constitution, while the Islamic guiding document proclaiming equality is the Koran (MS Encarta, 2003). Still, st atus and financial power in both cultures are the sources of social inequality. The United States places a strong emphasis on status-defining factors like money, and power (Chapter 9). Similarly, the Egyptian society comprises of the ruling minority of Afrangi, high government officials, and academicians, and the ruling majority of natives, Baladi (Tehuti Research Foundation, 2003).The individualistic American society is much different from the group-oriented Islam, where family traditions are highly cherished (Chapter 10).

Information sources in marketing Term Paper Example | Topics and Well Written Essays - 1250 words

Information sources in marketing - Term Paper Example They also contain accurate information on past financial activities and thus act as reliable historical sources of information on financial management (Mort, 2003). Information sources in financial management also dwell on financial accounting, its principles and its assumptions. These sources analyze the international accounting standards that are upheld in terms of analysis and presentation of financial information. Some of them give a good analysis on currencies in Financial Management. The world has many currencies; as many as the number of countries available. These currencies vary in their market strength, and studying them is essential in establishing their relationship. It also enables one to compare the imports and exports of countries in terms of foreign exchange and international trade. To add to this, one gets to understand the various Fiscal policies and their implications in the modern financial markets. The information sources in this field of business are easily available. They exist in both soft and hard copy, with some being exclusively digital sources. Audit and government institutions provide this information through the cri tical analysis of the economy. There are various communication structures in Financial Management. These include associations, societies and journals. Some of the major associations include the Financial Management Association. This association supports scholars in various financial grounds and activities. It assists in the professional, academic and day-to-day life development of college students who are interested in banking, real estate, investment management and financial management. It gives them a firm background and foundation in their business studies, enabling them to be among the best in the financial industry. The European Financial Management Association is another association that is used as a communication

The Constitution and the U.S. Government branches Assignment

The Constitution and the U.S. Government branches - Assignment Example To gain efficiency in subsequence, the US Constitution has significantly divided the federal government into three branches i.e. Legislative Branch, Executive Branch and Judiciary Branch (Trethan, 2013). Article 1 of the US constitution describes its Legislative Branch, which includes two main bodies – namely ‘House of Representatives’ and ‘Senate’, collectively known as Congress. These bodies are vested with the authority to frame laws for the nation. Article 2, correspondingly describes the Executive Branch, which is governed by the US President. The President of the nation executes the federal laws as well as makes necessary recommendation regarding new laws (Minnesota House of Representatives Public Information Services, 2014). Additionally, in accordance to this branch, the President directs the national defense as well as formulates foreign policies and endures the various ceremonial duties. The third constitutional branch, as mentioned under the US Constitution is the Judicial Branch. Article 3 of the constitution herewith covers the Judicial Branch, which is headed by the US Supreme Court. In this regard, the key power of this branch is to un derstand and evaluate the entire Constitution, appraise laws and make decisions relevant to various cases that are engaged with the rights of the states (Mount,

Golden Ratio Essay Example for Free

Golden Ratio Essay The Golden Ratio which is also referred to as golden mean, golden section or divine proportion is a number frequently encountered when calculating ratios of distances particularly in simple geometric figures like pentagram, dodecahedron, pentagon and pentagram. It is an irrational constant in mathematics which is given an approximate value of 1. 6180339887 and is symbolized by the Greek letter phi or in other words , or sometimes . Most of the greatest mathematicians in the ancient Greece, Euclid and Pythagoras along with Leonard of Pisa who was medieval Italian Mathematician together with Johannes Kepler, Renaissance astronomer and the present day scientific individuals like Roger Penrose, Oxford Physicist have spent a lot time in studying this ratio along with its properties (Weisstein, 2010). The Ancient Greek mathematicians initially studied the Golden Ratio simply because it frequently appeared in geometry. The Greeks have always attributed the discovery of this ratio to Pythagoras along with his followers. The Golden Ratio was first used by Martin Ohm in his 2nd edition book Die Reine Elementar-Mathematik in 1835. The fascination of this concept is not confined to mathematicians but also artists, musicians, biologists, mystics, architects, historians and psychologist have debated and pondered the basis of its appeal and ubiquity. Prof. Michael Maestlin wrote the first approximation of the Golden Ratio in 1597 and stated it to be about 0. 6180340. It is fair to declare that the Golden Ratio have brought inspiration to most thinkers of various disciplines than any other number has done in the history of mathematics (Weisstein, 2010). The Golden Ratio in Art Just as the Golden Ratio is used in the beauty and design of nature, it can also be applied in achieving balance and beauty in the design of art. This is just a tool for composition although it is not a rule. Leonardo Da Vinci, used the Golden Ratio intensively in designing and in many of his paintings, he featured the Golden Ratio which he called the â€Å"divine proportion†. This he did after his exploration of the human body by engaging in the ratios of the lengths of different body parts. His illustration of the polyhedra on the divine proportion, and his perspective concerning the body proportions portraying the Golden Ratio has led to the speculation by some scholars that he used Golden Ratio in painting. This speculation has been seen in his Mona Lisa painting where it employs Golden Ratio proportion. The Sacrament of the Last Supper, which is a painting by Salvador Dali explicitly, illustrates the application of the Golden Ratio. The canvas’ dimension is that of the golden rectangle and what dominates the composition is the large dodecahedron which has its edges in Golden Ratio and swings above and behind Jesus. Other paintings speculated to symbolize the Golden Ratio are Holy Family by Micahelangelo, Crucifixion by Raphael, Self-portrait by Rembrandt, Golden Section Plate by Fletcher Cox and Bathers by Seurat (Obara 2010). The Golden Ratio in Architecture The Ancient Egyptians became the first individuals to apply mathematics in art. It is obvious that they did this by ascribing magical properties of the Golden Ratio and henceforth using that in designing their great pyramids. Some studies regarding the Parthenon and Acropolis offer a conclusion that most of its proportions give an estimated value of Golden Ratio. The facade of the Parthenon along with the elements of its facade are suspected to be circumscribed in terms of golden rectangles. The fact that the proportions of the classical buildings or rather their elements are according to the Golden Ratio clearly explain that the architects who designed them were conscious of the Golden Ratio and applied it in their designs. On the other hand, it is possible that the architects applied their special sense of good proportion and as a result their proportions gave approximate of the Golden Ratio (Obara 2010). According to a geometrical analysis carried out by Boussora and Mazouz concerning to the Great Mosque of Kairoua, it is evident that there was consistent utilization of the Golden Ratio in its design. The Golden Ratio is applied in the overall proportion of the plan along with the dimensioning of the court, the prayer space and the minaret. Mazouz and Boussora further scrutinized earlier archaeological theories concerning the mosque and demonstrated the Golden Ratio in the geometric constructions through the application of the constructions on the plan so as to test their hypothesis(The Golden Number). Le Coubusier explicitly applied the Golden Ratio specifically in his Moduaor system which he saw as a continuation of the traditions of the work of Battista Alberti, Leonardo da Vinci’s â€Å"Vitruvian Man† and others who applied the human body proportions to improve the function and appearance of architecture. Mario Botta, a Swiss architect based most of his designs on figures of geometry. Some of the private houses which he designed in Switzerland consist of cylinders, squares, cubes and circles. In Origlio, Mario has designed a house with the proportion of the Golden Ratio between the side sections and the central section of the house. In a recent book by Jason Elliot, it has been contemplated that the Golden Ratio was utilized in designing the Lotfollah mosque and Naqsh-e Jahan Square. The Golden Ratio was also used in designing the Notre Dame in Paris in 1250 (The Golden Number). Conclusion The idea of translating beauty into a simple number, the Golden Ratio is quite disturbing. It is true that beauty is not something that is so substantial in something like a lifeless number but rather something we all have to make personal choices regarding it. Basing on the rule of thirds that is used in photography, for a photo to emerge appealing and balanced, the image must be made to abide by the grid that is divided into thirds. The number of comments that a person receives directly correlates with the beauty found in his/her image. Though, there are other factors that affect how people view a person or something, good comments are given depending on how the image appeals the eyes. For attractive people like Angelina Jolie and Brad Pitt, the skeleton of Golden Ratio almost fit perfectly on them. However, when the skeleton was put on a picture of an individual who looked a bit unattractive, the skeleton did not fit. I am not suggesting that beauty should be translated into being lifeless and cold because of it being defined inform of numbers. However, I think that the paintings and houses that used the proportions of the Golden Ratio look appealing and beautiful. In my opinion therefore, physical beauty can be measured by Golden Ratio.

Reverse Osmosis for Wastewater Recycling Essay Example for Free

Reverse Osmosis for Wastewater Recycling Essay Reusing treated wastewater for beneficial purposes, such as agricultural and landscape irrigation, industrial processes, toilet flushing, or groundwater basin replenishment, is growing in response to environmental and economic concerns. One of the key factors involved in recycling wastewater treatment plant (WWTP) effluent for another use is the need to reduce total dissolved solids (TDS). This is often done by using a reverse osmosis (RO) system, which relies on pressure differential to force a solution (in this case, water) through a membrane that retains the solute on one side and allows the pure solvent to pass to the other side. While extremely effective on biologically treated wastewater, RO systems need to be coupled with an effective pretreatment system to avoid common issues that can result in system failure, including plugging, fouling, and scaling. One of the most effective pretreatment options for wastewater applications is membrane bioreactor (MBR) technology, in which a membrane process like ultrafiltration (UF) or microfiltration is combined with a suspended growth bioreactor. MBR provides high quality feed water to the RO, minimizes footprint and the cost of civil works, and reduces treatment plant downtime, thereby reducing operating costs. Koch Membrane Systems’ PURON ® submerged MBR technology has successfully been used as the pretreatment option for challenging industrial and municipal water reuse RO systems, and can help make water recycling technologies more cost-effective. Reverse Osmosis Systems Present Challenges for Water Reuse Pretreatment methods are critical when designing RO systems. For example, RO membranes used for most water reuse applications contain a brine spacer, typically made of low density polyethylene mesh netting. If there is a high level of suspended solids in the feed water, this brine spacer can become plugged. Another issue is the high levels of organics contained in many biologically treated wastewaters, which are rejected by the RO membrane and progressively concentrated as the water flows across the membranes. This concentration of organics can foul the membrane, especially towards the RO system outlet. Biofouling can also occur, because the organics in wastewater make an excellent food source for microorganisms. Also, some treated wastewaters contain high levels of bacteria, so biogrowth may occur quickly even if RO feed water is disinfected. Finally, calcium phosphate scaling can cause problems with RO systems operating on some wastewaters. The scaling can be mitigated by operating at lower water recovery, using acid or other antiscalant to minimize scaling, or modifying the operating conditions of the WWTP to reduce the amount of phosphate in the RO feed. These plugging, fouling, and scaling issues mean that the RO system needs to be operated at higher pressures, leading to increased power consumption, increased chemical costs for cleaning, and a shorter membrane life. How can these challenges be minimized and overall water reuse system lifecycle costs reduced? Effective pretreatment of the feedwater before it flows through the RO system is the answer, provided that the pretreatment steps are chosen carefully to ensure that the RO system can work as intended. Reverse Osmosis Pretreatment Options There are many different pretreatment options, and the best for a particular process depends on power, chemical, labor and land costs, wastewater source, and the existing wastewater treatment system. Conventional Pretreatment The conventional effluent pretreatment scheme might be primary treatment, biological treatment and, the most crucial part of the process, solids-liquid separation using secondary clarification. The conventional sedimentation process often doesn’t remove enough bacteria and suspended solids, so sand filtration may be added to improve the solids-liquid separation and provide higher quality water to feed the RO system. Using ferric chloride along with the sand filtration may enhance solids and organics removal. However, upsets in the secondary clarifier can lead to effluent with higher levels of TSS and BOD, causing plugging of the brine spacer with suspended solids and organic fouling. Also, power consumption for RO systems with this type of pretreatment tends to be high, and membrane life is often quite short. Lime-softening has been somewhat more successful in protecting the RO membranes, but this increases operating costs and does not totally prevent fouling of RO membranes. Ultrafiltration Improves Suspended Solids Removal As RO Pretreatment Many of today’s water reuse systems use an ultrafiltration (UF) pretreatment step to emove suspended solids. These systems typically use hollow fiber UF membranes, which do an excellent job of providing water with low suspended solids to feed the RO system. However, the UF system is an extra treatment step, requiring additional footprint, and adding to operating costs. The UF system may also be susceptible to upsets from a conventional WWTP, which can further increase its operating costs. Membrane Bioreactor As RO Pretreatment With an MBR, the UF membranes are submerged in the activated sludge to combine the biological step and the solid-liquid separation into a single process. The membrane acts as a barrier, which improves the effluent quality. The MBR eliminates the secondary clarifier and does not rely on gravity for liquid-solids separation and so allows the activated sludge to operate with a higher mixed liquor suspended solids (MLSS) concentration. The increased MLSS concentration reduces bioreactor tank volume, saving footprint and capital construction costs. Overall, the MBR process reduces footprint significantly compared to the combination of conventional activated sludge followed by sand filtration or ultrafiltration. The footprint savings due to the wastewater treatment plant alone can be as much as 50 percent, along with additional footprint savings from eliminating other filtration steps. Using MBR technology also simplifies the overall treatment train, minimizing the number of unit operations. Benefits Of Koch Membrane Systems’ PURON MBR Technology Koch Membrane Systems’ PURON submerged hollow fiber UF module offers robust, cost effective solutions for RO pretreatment. The patented membrane module contains hollow fibers, the lower ends of which are fixed in a header. The upper ends are individually sealed and are free to move laterally, as shown in Figure 1. The PURON module is submerged in the mixed liquor. All solids and particulates remain on the outside of the fibers while permeate flows in an outside-in pattern by means of a vacuum that evacuates permeate through the inside of the hollow fiber. | The free moving fibers, combined with central air scour aeration, ensure stable filtration during plant operation, long membrane life, and lower operating costs due to reduced need for energy, cleaning and maintenance. PURON MBR has been used successfully as the pretreatment step for a number of challenging industrial wastewater systems. For example, a Belgian firm that manufactures chemicals for film processing and printing uses large amounts of fresh water for cleaning and production. The firm began reusing its wastewater to reduce its fresh water costs, and selected an RO system to produce water with the low salt and nitrogen content required for its process. The firm installed a PURON submerged hollow fiber MBR as the pretreatment step prior to the RO, and the system has been operating successfully since 2005. Another example is an Australian malt-producing company that sought to reduce its use of fresh water by recycling its wastewater. PURON MBR technology was selected as the pretreatment step for the RO system, since it provided the best quality water to feed the RO while minimizing overall operating costs. The MegaMagnum ® RO system recovers the MBR effluent as product water for reuse. The system has been running since 2006. In fact, the RO permeate quality is equal to or better than the local potable water supply. Space Cost Considerations Treatment operation footprint is a primary consideration in developing the best treatment system. Since the PURON MBR system reduces the volume of the bioreactor tanks and eliminates the secondary clarifier, the footprint for an MBR process is much smaller than tertiary filtration steps with sand filtration or UF. If space is limited, MBR may be the only pretreatment choice that fits in the available space. Other considerations include costs of land, civil works, equipment, power, chemicals and labor, and the payback period used. High land and civil costs tend to favor MBR use. For large municipal treatment facilities requiring RO as a final treatment step, an MBR should compare favorably to conventional wastewater treatment as a pretreatment step prior to RO. In a 20-year analysis the municipality should realize savings in RO membrane replacement and power as a result of the MBR pretreatment step. For an industrial company looking at a short payback, the preference for conventional or MBR technology will depend on the relative cost of civil works and land versus the equipment cost. Conclusions Using RO systems to reclaim and recycle wastewater effluent is growing rapidly, and Koch Membrane System’s PURON MBR technology is now being considered as the pretreatment option for an increasing number of industrial and municipal reuse applications. The PURON submerged membrane modules provide high quality feed water to the RO, minimize footprint and the cost of civil works, and reduce the susceptibility of the RO treatment train to upsets. PURON is a trademark of Koch Membrane Systems GmbH and is registered in Austria, Benelux, Canada, China, France, Germany, Italy, Oman, Saudi Arabia, Spain, Taiwan and the United Kingdom. MegaMagnum is a registered trademark of Koch Membrane Systems, Inc. in the United States and other countries. Wastewater Recycling for the Stone Fabrication Industry As a stone fabricator you’re looking for a wastewater treatment system that keeps you in compliance, but wouldn’t it be nice to save some money too? That’s where our wastewater recycling and treatment systems come in. These zero discharge, closed loop systems collect the water you use for polishing, cutting, and other processes; cleans it thoroughly, and recycles it so you can use it again. Your wastewater is never discharged into the public system during this process, so you have no chance of being out of compliance. Between the money you’ll save on non-compliance fees and the reduced cost of your water bill, the return on your investment will be substantial. And because we use the most durable, well-designed components on the market in each wastewater recycling system, you can be sure this system will run efficiently for as long as you need it to. We even design and manufacture some of those components in house, including: * Filter presses * Clarifier systems * Chlorine dioxide generators * Control panels * More The solid, smart construction of our zero discharge wastewater recycling systems results in a wide variety of beneficial features, including automation options, expandable filter presses that can accommodate your business as it grows, the ability to accommodate flow rates for 10 GPM – 200 GPM, the ability to filter solids water down to below 1 micron, and more.

A Review of Literature of Erosion of Soils

A Review of Literature of Erosion of Soils Introduction Numerous work and research have been undertaken on erosion of soils for many decades. The following literature review is focusing on the relevant topics in terms of soil erosion process as well as the parameters and factors of soil erosion .Moreover, the literature reviews is primarily focusing on the management and control the soil erosion. 1 Soil Erosion by Water To perform this study, it was necessary to understand how soil erosion occurs. Usually it occurs at a low level but can become a problem when the ecological balance disturbed by humans activities or severe weather .The risk of erosion by water when soils with a high sand or silt content that exposed to heavy rainfall. (Defray 2005). It is crucial that considering rainfall and runoff factors when assessing a water erosion problem (BC.S.Baldwin 2003) .Although the soil erosion caused by long-lasting or less-intense rainfall is not as spectacular .But soil movement by rainfall is most noticeable during the short-time, high-intensity thunderstorms and the amount of soil loss can be considerably, especially when compounded over time. While the excess water on a slope that cannot be absorbed into the soil or trapped on the surface, the runoff will occur. The amount of runoff can be increased if infiltration is reduced due to soil compaction. (BC.S.Baldwin 2003) Two stages process involved in the soil erosion, which depend on water detaching and transporting soil. Rainsplash is a key determinant of detachment of soil particles in the first stage of erosion. However, if a growing crop covers the soil surface, the erosive power of rain will dramatically reduced. Once it detached, surface water run off plays a key role in the process of soil particles being transported. Surface run-off can be easily happening during the heavy storms or prolonged rainfall. (BC.S.Baldwin 2003) Tess Wynn investigated the streambank retreat. Normally it is called streambank erosion, the occurrences involved the combination of three processes, subaerial process, fluvial entrainment and mass wasting. Specifically. The term â€Å"subaerial process† is used to describe the climate- related phenomena that reduce the strength of soil .It mainly controlled by climatic conditions, and overly independent of flow. Subaerial processed are often called â€Å"preparatory processes† due to they increase the susceptibility of soil to erosion at high flows (Wolman, 1959;Lawler, 1993) Apparently. Fluvial entrainment means the direct removal of soil particles or aggregates from the streambed or banks by flowing water. (Tess Wynn 2006), but the fluvial erosion of cohesive soils is extremely complex and related to soil properties and test conditions (Grissinger, 1982). The susceptibility of a cohesive soil to erosion influenced by numerous of the parameters of soil, including grain size distribution, soil density, pore water content and chemistry (Grissinger, 1982) Mass wasting also known as bank failure, it occurs when the weight of the bank exceeds the shear strength of soil. The mass wasting can be attributed to increasing the bank height or bank angel due to fluvial erosion or the presence of tension cracks (ASCE, 1998).Research has proved that bank geometry, properties of bank materials and the density and the type of bank vegetation play the key role the occurrence of mass wasting. Hu Liu, Theodore G. Cleveland, and Keh Han Wang conducted the laboratory tests of dependence on properties of soils and. In their study, rainfall was generated by the rainfall simulator; along with flume .The rainfall simulator consist of a wooden frame and a group of PVC pipes with small holes. The soil sample was placed at one end of the flume .In the experiment, the simulator activated by the adjustment of the slope. In addition, six type of soil with different texture and classifications used in this laboratory experiments. The results show more soil erosion produced by the higher rainfall intensity. Besides, the unit soil volume loss affected by shear strength, compressive strength and rainfall intensities but less influenced by the bed slope. (Hu Liu, Theodore G. Cleveland, and Keh Han Wang, 1999) Jill Fernqvist and Ida Florberger conducted their research in South Africa .Their study indicated the fires are one the important factor that changes the soil properties .their study has been taken in the Western Cape,. The fieldwork focused on water repellency has detrimental influence upon the post-fire erosion Jill Fernqvist and Ida Florberger(2003) 2 Soil Erodibility Soil erodibility is an estimate of the ability of soils to resist erosion in term of the physical characteristics of soil. Generally, the faster infiltration rates of soil, the higher levels of organic matter and improved soil structure have a greater resistance to erosion silt, very fine sand, and certain clay textured soils tend to be more erodible than Sand, sandy loam and loam textured soils cropping practices which lower soil organic matter levels, cause poor soil structure, and result of compacted contribute to increases in soil erodibility. Compacted subsurface soil layers result in decreased infiltration and increased runoff. A formation of a soil crust, can create the decreased of infiltration, however, normally the growth of runoff water is attended by the greater soil erosion problems. (BC.S.Baldwin 2003) There is a definite link between Past erosion and soils. The original soils tend to be less erodible than the exposed subsurface soils on eroded sites were, owing to their lower organic matter or poorer structure .The lower nutrient levels usually related with subsoils contribute to lower crop yields and generally poorer crop cover, which in turn provides less crop protection for the soil. (BC.S.Baldwin 2003) Gregory J. Hanson provided the complex problem about how to predict the erodibilty of soil material by flowing water. Base on the knowledge of hydraulic characteristics and the characteristics of cohesive soils .Laboratory Jet tests were carried out on soil samples compacted at different moisture content dynamic. Jet detection apparatus and method description of the excess stress parameters determined kd and tc. An example of this is used to test the soil in the laboratory to determine the appropriate placement in the field. The flume tests and field trials were carried out to verify the plane corrosion. (Gregory J.2002) 3 Slope Gradients and Length Basically. The steeper slope areas, the greater amount of soil erosion by water.Soil erosion of water also increased with slope length due to the greater accumulation of runoff. The consolidation of small fields into larger results is often no longer the slope length of the potential for erosion, because water with an increase rate that allows a greater degree of scouring (carrying capacity of the sediment) (BC.S.Baldwin 2003) 4 Soil Deposition Soil particles of all sizes may be moved during run-off. When flow stopped, these start to settle. According to the US Environmental Protection Agency (USEPA), sediment is a root cause of water quality impairment (USEPA, 2002).excess Suspended sediments to reduce diversity and rich of aquatic organisms, reduce reservoir capacity, improve drinking water treatment costs, and serve as a carrier of pollutants.(Tess Wynn,2006) The erosion process of cohesive sediment was studied in Masato Sekine and Nobuaki Iizuka study .To full understand the process, they also conduct an experiment .Clay mixed with different compositions were used to test samples of the form of erosion of water pipes in a closed experimental apparatus. Specifically .Experiments carried out a square circle closed pipeline system cross-section 400 centimeters in length and 10 centimeters wide, 10 centimeters deep. 5 Vegetation The potential of soil erosion is increased, if the soil with little or no vegetation, plants and crop residues. Residue cover to protect plants and soil from rain splash, tends to slow down surface runoff flows, and ensures excess surface water infiltration. Erosion soils reducing the efficiency of the plant or residue cover depends on the category, degree and quantity of cover. Combination of vegetation and residue completely covered the soil, and to intercept all falling raindrops, and near the surface and the most effective control of soil (such as forests, permanent grassland). Part into the residue and the root is also very important because they provide the channel that allows surface water into the soil. The effectiveness of any crop, management system or protective cover also depends on how much protection can be at different times during the year, the relative amount of erosive rainfall during these periods belong to. In this aspect , the crops with food, protective cover a major part of the year (for example, alfalfa or winter cover crops) can reduce soil erosion can be far more than crops leave the soil bare for a longer period of time (such as row crops) , especially during the high erosive rainfall (spring and summer).( C.S.Baldwin 2003) I.J. Shelton also investigated tillage operations influence upon the soil erosion, which depending on the depth, direction and timing of the plowing, the types of farming equipment and a number of passes. Generally speaking, the less interference or residual vegetation cover at or near the surface, the more efficient farming practices, and reduce soil erosion (I.J. Shelton 2003) Soil erosion potential is affected by tillage operations, depending on the depth, direction and timing of plowing, the type of tillage equipment and the number of passes. Generally, the less the disturbance of vegetation or residue cover at or near the surface, the more effective the tillage practice in reducing erosion. Regarding the effects of vegetation on streambank stability , Tess Wynn examined the vegetation influences the chemical and properties of steambanks and the local micro climate .The multiple effects on subaerial process produced by riparian vegetation including the dense cover of vegetation absorbs the energy of rainfall ,reducing soil detachment by raindrop . But it should be noted that the effects of vegetation on stream hydraulic varies with the stream stage, width and season. Additionally. Distribution of energy and sediment in a stream influenced by the vegetation. (Tess Wynn 2006) Tess Wynn 2006 addressed the vegetation cover problem. Extensive erosion by wind may result from the lack of permanent vegetation cover in certain locations. Loose, dry, bare soil is the most susceptible; however, crops that produce low levels of residue also may not provide enough resistance. Besides, crops that produce a lot of residue which not protect the soil in severe conditions. Therefore, an adequate network of living windbreaks along with good tillage, residue management, and crop selection are considered to be the most effective vegetative cover for protection. (Tess Wynn 2006) South Africa is a country which lack of the water, but the Jill Fernqvist and Ida Florberger have described the theory of fire -induced water repellency and the following soil erosion in their study. Generally, In South Africa, alien species require more water than the indigenous one. Therefore, alien vegetation provides a poor ground cover compared to the indigenous vegetation, which could result in surface run off and soil erosion (.Jill Fernqvist and Ida Florberger 1996). Jill Fernqvist and Ida Florberger observed the Alien vegetation apparently has been considered as a key issue in the ecosystem of Western Cape. Water yield was decreased in the long term due to the alien vegetation consume a large amount of water, as a result, the biodiversity is threatened. In addition, fire in the alien vegetation for the results of erosion-prone slopes. (Jill Fernqvist and Ida Florberger, 2003) Defra (2005) summarized the Management Practices using Vegetables and Salad Crops in soil erosion Control. And offered some solutions to prevent the soil erosion when undertaking the cultivations, irrigation and harvest. (Defra 2005) 6 Soil Erosion by Wind Soil is also erosion by wind, although the effect is not noticeable like the erosion by water. C.S.Baldwin studied the rate and magnitude of soil erosion by wind is decided by many factors: Erodibility of Soil The wind suspends very fine particles and then transported great distances. Fine and medium size particles can be lifted and deposited by wind. While coarse particles can be blown along the surface (commonly known as the saltation effect). Soil Surface Roughness Soil surfaces only provide little resistance to the wind. However, ridges can be filled in and the roughness broken down by abrasion to produce a smoother surface susceptible to the wind in a long time. Excess tillage is a threat to soil, because it breakdown the soil structure and increased erosion. Climate There is a define link between the speed and duration of the wind and extent of soil erosion. The levels of Soil moisture can be very slightly low at the surface of excessively drained soils or during periods of dro ught, and releasing the particles for transport by wind. It occurs in freeze drying of the surface in winter. Adverse operating conditions maybe created by wind erosion in the field. Crops can be completely ruined so that costly delay and reseeding is necessary (C.S.Baldwin 2003) 7 Effects of Soil Erosion The negative changes from bank erosion including farmland productivity losses, damage to building structures such as bridges, roads etc. I.J. Shelton defined the on-site effects and off-site effects. On-site effects mean extension of the elimination of the impact of soil erosion of valuable topsoil. Crop emergence, growth and yield a direct impact on the loss of, natural and applied fertilizer and soil nutrients. Seeds and plants may interfere with or completely abolish the erosion site. Organic matter in soil, residues and any applicable fertilizer, a relatively light weight, can be transported off-site, especially in the spring thaw conditions. While the off-site effect is not always obvious as on-site effects, but Eroded soil, deposited down slope can inhibit or delay the emergence of the seed, bury small seedling, need to replant in the affected areas. Soil quality, structure, stability and texture can be affected by the loss of soil. The breakdown of aggregates and the removal o f smaller particles or entire layers of soil or organic matter can weaken the structure and even change the texture. Textural changes can in turn affect the water-holding capacity of the soil, making it more susceptible to extreme condition such a drought. (I.J. Shelton 2003) According to the C.S.Baldwin (2003), Sediment can contribute to road damage, accelerate bank erosion, and reduce downstream water quality. What is worse, Pesticides, and fertilizers, which contained in the soils. They frequently transported with eroded soil pollution or contamination of water downstream and entertainment district. 8 Conservation Measures While, based upon research, various conservation measures can be taken to reduce soil erosion by both water and wind. Tillage, cropping practices, and land management practices, have a direct impact on the overall soil erosion problem and solutions to a farm. When crop rotations or changing tillage practices are not enough areas where erosion control method or a combination of more extreme measures may be necessary. For example, contour plowing, strip cropping, or terracing may be considered. (C.S.Baldwin 2003) The defra (2005) advised measures about how to control the soil erosion. In their study, four categories of solution were presented. It is crucial to understand that erosion control on susceptible soil types can be successfully achieved to reduce the impact of rainfall erosion and maintain soil infiltration rate, so that the surface flow are avoided. It can be achieved by 1 To protect the soil from rainfall impact, whether it is permanent vegetation cover or land rotation, timely crop establishment and retention of surface crop residues. 2 Avoiding smooth, flat finishes to exposed field surfaces, so that good water seepage rates remain unchanged. 3 Avoiding tramlines, wheeling or cultivation features that can channel surface flow. 4 Seeking to increase the organic matter content in the means of improving the stability of the soil in the longer term. Steep slope and erosion because of increased risk, the efficiency of these measures is becoming increasingly important. When deciding on the combination of measures to apply in any particular situation, consideration should always be the serious erosion that may occur, if the case happened. In some cases, a measure aimed at controlling erosion may increase. For example, work along the contour is sometimes used to reduce runoff, but if the profile is not strictly followed, the accumulation of water at low points which might break over the cultivation features. (Defra 2005) Meanwhile, good management practices play a pivotal role in the control of soil erosion. Some examples and considerations were presented in defra (2005) study. In order to minimize the soil erosion when soil in the most vulnerable condition, the different type and timing of cultivations should be planned. Obviously, the overall aim should be the soil maintain in a less vulnerable condition as long as possible .Therefore, defra (2005) provided the good management of the farm to reduce erosion risks in terms of seedbed preparation, directions of cultivations and irrigation. 9 Conclusion Soil erosion is a natural and slow process. It has the detrimental effect on the environmental. Normally the agents of soil erosion are water and wind, the soil erosion is affected by many factors .But soil erosion could be effectively controlled and minimized by taken appropriate measures. References Abernethy, B. and I. D. Rutherfurd. 1998. Where along a rivers length will vegetation most effectively stabilize stream banks? Geomorphology. 23(1):55-75 ASCE. 1998. River width adjustment. I: Processes and mechanisms. Journal of Hydraulic Engineering. 124(9):881-902. Coppin, N. J. and I. G. Richards. 1990. Use of Vegetation in Civil Engineering. Butterworths.London Department for environment food and rural affairs .2005 .Controlling soil erosion, Defra Publications, London. G.J.de Boer .2002.on the consolidation and erosion of cohesive sediments.Deflt University of Technology .Civil Engineering and Geosciences G. Wall, C.S. Baldwin and I.J. Shelton. 2003. Soil Erosion Causes and Effects .Face Sheet.Queen`s print for Ontario Jill Fernqvist, Ida Florberger 2003. 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