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SFSU Features and Structures of Linker vs Loader Comparative Essay

SFSU Features and Structures of Linker vs Loader Comparative Essay.

This is a WRITTEN ESSAY based assignment.Background:When you compile a program it produces an OBJECT file. A number of these object files (along with library files) are combined into an EXECUTABLE file by the LINKER. It is the linker’s responsibility to combine the objects and resolve as many references as possible and produce an executable format file. The LOADER Is responsible for converting the executable image on disk to a runnable process in memory. This involves the relocation of the program to its starting point in memory as well as any dynamic linking and loading. Task:Compare and contrast the linker versus the loader and detail the features and structures of each. Show the actual specification of the embedded data structures and how they are transformed in the linking and loading processes.Requirements:The paper must include an abstract, detailed explanations, diagrams, references and were necessary a glossary of terms. The paper must also include a detailed bibliography of all cited and referenced materials. It is expected that this paper be at least 4 pages in length not including diagrams, abstract and bibliography. Grading:This paper will be graded based upon its completeness, accuracy, and clarity. Failure to site references will result in that aspect of the paper being ignored and not counted in the grading.
SFSU Features and Structures of Linker vs Loader Comparative Essay

Chapter 2- Literature Review 2.0 INTRODUCTION After the abolishment of the rail system in 1964 for economic reasons, road has been the only means of mobility for people and good inside Mauritius. With the economic growth of the country there has been progressively development on the road infrastructure. However, the development has brought about an increase in traffic on the Mauritian Road network and various researches have been done to show its impact on the economy. Hence, we will try to understand how public investment in road infrastructure affects the economic performance of Mauritius while at the same time shedding some light on how these investments are, and could be, financed. 2.1 Economic Benefits of Transport Infrastructure: 2.1.1 Demand Side Policy Road infrastructure in Mauritius is the most important factor which has enabled economic activities to take place. In 2011, there was approximately 2112 Km of main roads in Mauritius. Investment in road infrastructure is very important for an economy as it allows goods and services to be transported more quickly and at a lower cost. As a result, it lowers the prices for consumers and increases the level of productivity for firms. Evidently, we witness the number of Lorries and trucks full of goods on our main roads, for instance, the sugar cane production have to make use of the roads to deliver the raw cane to the factories. The tourism industry, the manufacturing sector, the agricultural sector, the financial services industry, the ICT as well as the seafood hub industry needs the transport infrastructure to operate. Eventually, the improvement in the road infrastructure has been able to reduce the delivery time to transport goods. That is, firms are able to receive their raw materials at the right time without having to delay their production process and deliver their finished goods to the supplier without having to make their customers to wait. Hence, reduction in delivery implies lower labor costs and more efficient use delivery vehicles, which results in a reduction of the firms’ expenses. Also, a reduction in delivery time is very profitable for firms specializing in perishable goods as this increase the chance that the good reach the customer in a good state. Transportation investment reduces inventory costs, as firms do not have to stock their raw materials for a long period for time. Thus, their storage costs are minimized and they can take advantage of just-in-time system. Hence, these results in a reduction of the cost of production and an increase in productivity which makes it easier to reduce the price of the good. Additionally, development in road infrastructure, also allows employees to reach their place of work in time. That is, this increase efficiency in productivity and less complaints about congestions. Also, the employees become more efficient as they have not spent mostly of their energy in travelling and this increase their willingness to work. As seen before, improvement in transportations have brought an improvement in logistics. That’s it refers to the improvement in transportation and about more efficient management of inventory. Consequently, this enhance the business reorganization effect, that is, when the productivity has increased, the national economic welfare is enhanced; firms are able to produce more or better goods and services than before. Table 1.1: own illustration 2.1.2 Supply side policy The Supply- side Economics developed during the 1970’s in response to the Keynesian economic policy after the failure of the demand management during the stagflation of the 1970 to stabilize the Western Economy. Therefore, as in classical economy, supply- side economists put a primacy on the production of goods and services, rather than on demand for those goods and services. Hence, investing in the infrastructural development can be seen as an opportunity to make use of the available underutilized resources (especially labour). Road infrastructural development has been creating many jobs in Mauritius, starting from road contractors, site managers, and accountants, engineers to those workers involving raw inputs like cements, gravel, and asphalt and drivers. According to 2011 statistics, there were 46100 persons unemployed in Mauritius, thus this means that there is large pool of unemployed workers who can be used to improve our infrastructure. Therefore, infrastructure investment would provide an opportunity for construction workers to productively apply their skills and experience [1] . Additionally, according to the multiplier theory, an initial injection will make the national income increase eventually by a figure which is higher than the injection itself. That is, by injecting in the road investment, this will cause several round of expenditure to occur that is, more labour will be employed, more raw materials will be demanded, causing the raw material industry to produce more and hiring more factor of production (labour). The increase in workers will eventually cause an increase in demand of goods and services and consumption. Consequently, there are multiple expenditures that follow and gradually spread all over the economy to all sectors; primary, secondary and tertiary. 2.1.3 The Costs of Not Investing in Infrastructure Investing in infrastructure is expensive, but not investing in infrastructure also is expensive. There is opportunity costs of not investing in infrastructure include: increased congestion, no forward linkages [2] , absence of competitive edge in moving good, foregone productivity and jobs. Mauritians waste a lot of time stuck in traffic and it is said that the traffic congestion costs the Mauritian economy around Rs 2 billion per year (Mauritius Road Development Authority). Thus, this Rs 2 million could have been use for other purposes instead of being wasted. Also, congestion does not only affect the economy but also the environment. The major cause of traffic congestion is the significant increase in the number of vehicles on the road, which was not accompanied by adequate road infrastructure. For instance the total vehicles on the road was 291,605 in 2004 and 400,919 vehicles registered in 2011 at the National Transport Authority while the road network only increased from 2,020 km in 2004 to 2112 km in 2011 (Digest of Road Transport and Road Act) 2.2 Understanding the Links between Transportation and the Economy There have been several debates on the linkages between transportation and the economics performances. However, three methods that helped once to determine the link between transport infrastructure and economic growth were the macroeconomics, microeconomic research and the General Equilibrium Approaches. 2.2.1Empirical Road infrastructural development and its impact on economic performance has not been a common area of research in Mauritius. The rare literature available for our country is available in Khadaroo and Seetanah (2008) and Zainah (2009), with the former using a dataset of 50 years up to the year 2000 and showed that the long run effect of transport capital to output(0.263) is posiive and also higher than the short run effect(0.145). However, on a global perspective, this area has had a vast number of researches, with the most important starting in the U.S in the late 1980’s. Public Infrastructure, which comprises of road investment as well, is used in many notable studies. Among the main type of methodology used, we have got work done at both Microeconomics and Macroeconomic level. Microeconomics analysis is done by estimating all the costs and benefits if road infrastructure projects. Knaap and Oostervahen (2003) worked at micro level and found than mature economies have little effect of improved infrastructure. A theoretical work of the importance of transport is found in the SACTRA report (1999). A 20% total time to be saved from road improvement in certain regions is presented in this report. However, Cost Benefit Analysis does not take into account the broader effects of public infrastructure on the general economy, as often required by policy makers (Lakshmanan, 2011). The present study is based on the macroeconomic impact of road infrastructural development. The basic method for incorporating public infrastructure in the literature is by the Production function approach in a static econometric model. An extended Cobb- Douglas function is used as proposed by Aschauer (1989): ; Where Y is the level of output, A is the level of productivity, K is the private capital stock, L is labour employed, and S is the government funding. The pioneer work of Aschauer (1989) measured the impact of public infrastructure on productivity and Gross Domestic Product (GDP) of the US during the period of 1949 to 1985 revealed the importance of public capital to productivity. Moreover, he estimated an output elasticity ranging from 0.39 to 056 with respect to public capital and a significant 0.24 in the case of core infrastructure (including transport). A similar work was carried out by Munnell (1990) with modification being made by adding Marginal Factor Productivity with transport capital stock. Her model was a Log-linear production function with data used for the period of 1948-1987. Her result showed a significant impact, more precisely, for a 1% increase in public capital, productivity would be raised by 0.34%. Based on the criticisms of the Production function approach and insignificant results (see Tatom, 1991), many studies then triggered off by using the Cost Function Approach. Lynde and Richmond (1992) used data form 1958-1989 found an output elasticity of 0.20% of public capital stock to productivity while Nadiri and Mamuneas (1993) obtained a negative effect of -0.05% to -0.21%. Other studies include that of Morrison and Shwartz (1996) and Gillen(1996). It should be highlighted that, despite many work being carried out in this field, there is a wide discussion on whether transport really has a significant impact on a nation wealth. Button (1998) questioned ”about whether infrastructure provision actually foster economic development or whether it is provided as a product of the economic development process. Banister and Berechman (2001) goes further by saying that economic growth happens modestly from infrastructure improvement and instead it is capital, labour and others that triggers growth (Looney, 1997). Following debate over the causality of Public Infrastructure and economic growth, in the last decade many studies have been using the Causality Approach (Herranz-Loncan, 2007) and others using dynamic econometrics framework (see Khadaroo and Seetanah, 2008; lakshmanan, 2011; Pradhan and Bagchi, 2012) . Herranz-Loncan (2007) carried out a study using the VAR model for the period of 1850-1935 for the Spanish economy found that only for individual state level infrastructural improvements had an impact on growth as compared to national level development had insignificant impact on growth rates. Pradhan and Bagchi(2012) recently found bidirectional causality between road transportation and economic growth. They used data for the period of 1970-2010 applied to the Vector Error Correcting Model (VECM). Same findings were made for road transportation, capital formation, Gross Domestic Capital Formation and economic growth. They suggest that expansion of transport infrastructure (mainly road and rail) along with gross domestic capital formation will lead to substantial growth of the Indian economy. Sturm, Kuper and De Haan (1995) found that Basic Infrastructure such as roads, railroad, harbor, etc.. had Long Run benefit on the Netherland economy whilst Complementary Infrastructure in the likes of electricity, water supply, gas had only short term effects. They found an output elasticity of around 0.3% with respect to public capital. A pioneer work on road infrastructure and economic development was carried out by Queiroz and Gautam (1992) where they empirically showed a significant correlation between kilometers of paved roads and GDP in a cross section analysis of data from 98 countries. Averaged density of paved roads (km/million inhabitants) and road conditions were found to be associated with economic development. Last but not the least, developing countries has also attracted interest in the empirical analysis, albeit it is very few. This is due mainly due to unavailability of data, specially for African countries. One of the most referred paper for developing countries is that of Looney (1997). The former studied public capital to explain a significant effect on Pakistan’s economic growth over the period of 1973-1990. Table 1.2: Summary of some major studies Study Dataset Results/ Output Elasticities Aschauer(1989) 1949-1985 0.39-0.56 Munnell(1990) 1948-1987 0.34-0.37 Garcia-Milla and Mc Guire(1992) 1969-1983 0.04( but significant for highways and education) Lynde and Richmond(1993) 1959-1989 0.20 Canning(1998) 1950-1995 significant Fernald(1999) 1953-1989 0.35 Khadaroo and Seetanah(2008) 1950-2000 0.263(Long Run result) Pradhan and Bagchi(2012) 1970-2010 significant Nadiri and Mamuneas(1993) 1947-1989 -0.05 to -0.21 Tatom(1991) 1949-1985 not significant 2.3 Financing of Road Infrastructure Studies about road infrastructure in Mauritius have mainly focused on the link about growth and road infrastructure. Hence, we wish to analyze how those investments have been financed and what are the future financing projects and its impact on the Economy. Facing morning and afternoon traffic congestion which is estimated to cost the Mauritian economy around Rs 2 billion annually, the Road Development Authority is implementing a Road Decongestion program projects via PPP that will include the operations and maintenance of the entire Road decongestion program as Mauritius’s first user pay toll road. 2.3.1 What is Public private partnership? The U.S. Federal Highway Administration states that “Public Private Partnerships (PPPs) are contractual agreements formed between a public agency and private sector entity that allow for greater private sector participation in the delivery and financing of transportation projects”. That is, the private entity performs part of a government organization’s service delivery functions, and assumes the associated risks for a significant period of time. Hence, in return the private entity receives as benefit a financial remuneration from either the governmental budget or the user charges or from both. PPPs have been used in many countries to deliver infrastructural projects including Australia, Italy, Greece, UK, France, Portugal, Spain or Germany. Several literatures have analyzed the cost and benefit of PPP scheme in transport. For instance, De Palma (2007) elaborated on the reasons about increasingly involvement of the private sector in the construction and operation of roads globally. He explained that normally public funding is insufficient to meet the increasing demand for road infrastructure and that nowadays the principle of the user should pays is widely acceptable. Moreover, he also stated that commercial pressures can encourage private operators in terms of lower maintenance costs, toll collection and other operating costs than the public sector. In addition, he supported his views with economic theories, which suggest that private firms have the incentive to take the responsibility of congestion and user costs borne by the customers. Furthermore, Debande (2001) who studied the consequences of the private sector involvement in the transport infrastructural projects concentrated about the benefits of the PPP scheme. Firstly, Debande (2001) stated that, “recourse to the private sector to finance and operate infrastructure projects will improve the ex ante screening and monitoring of a project and increase its productive and managerial efficiency”. Additionally, he elaborated that the private sector who will take the responsibility for designing, constructing, financing and operating the infrastructure will consider it as his obligation to take full account of the risk associated. For instance, he will be able to have a better evaluation of the financial risk being responsible of the capital cost of the project and account for several other risks like managerial risk to improve service quality. Nevertheless, the main disadvantage of the private financing could be when it imposes its monopolist power. That is, road being an important factor in an economy, the private firm might use it for its own benefit by imposing strict rules on the Government or even stop its functioning if they are not satisfied, which would be at the cost of the economy. 2.3.2 What is Toll road? A toll road is one for which the driver is required to pay a fee or change to be able to use it.In a period of crisis and at the same time increasing public debt, toll road is considered as a measure to lower the burden of the government by financing the road development project to some extent. That is, toll can offer access to outside financing for countries facing budget problems and limited debt capacity. For the case of Mauritius, till now the fee amount has not yet been decided by the government. However, the Minister of Public Infrastructure and Transport, Anil Baichoo has announced that public transport and utility vehicles will be exempted from the charge. The toll will be introduced in places where alternate roads exist. Thus, drivers will be able to opt for the other way if they want to avoid the toll payment. Those who pass through the toll roads will benefit from a grant from the government. The experience of toll roads started many decades ago and gained momentum recently with the privatization of the road infrastructural projects. Initially, it started in developed countries, mainly in Europe and the United States of America, and widespread in developing countries in Asia, Africa and Latin America with the Public Private Initiative of the World Bank. Italy was the first European country to apply the use of motorway toll near Milan in 1924. Also the first major toll road in the U.S is the Lancaster Turnpike, between Philadelphia and Lancaster which was built in the 1790’s. Additionally, the first toll motorway in U.K, the M6 toll is said to save motorists approximately 45 minutes on average journey time. It is operated under the private sector company Midland Expressway Limited which was granted a 53 year concession to operate and maintain the M6 Toll. 2.3.2.1 Advantages of toll roads Toll roads have been a subject of research for many decades because toll roads are expected to alleviate many existing issues due to traffic and transport. For instance, the main use of toll road is for reducing congestion. For instance, in Mauritius it is said that traffic congestion cost the Mauritian economy around Rs 2 billion which is indeed a huge sum. A major economic theory suggested toll road as a solution for market failure. Market failure occurs because of the presence of externalities. Hence, the term externalities can be defined as a situation in which the production and consumption of a good has an impact on a third party. For example, in case of roads, the decision of a driver to use a road can cause an externality on other drivers if his presence on the road network reduces the speed of all other users and increases their journey times. Thus, toll roads provide a solution for market failure as drivers pay a fee for traveling on some roads and the fee for traveling on a road reflects the size of the negative external effect imposed by each driver on other drivers. Evidently, the road users should consider the external costs occurred in the transport system such as the environmental costs, by internalizing the external cost (Tillema et al. 2003). That is, the one doing pollution is going to pay and his marginal willingness to pay be equal to total marginal social costs. 2.3.2.2 Empirical It is also said that collecting of tolls provides a mechanism for financing construction and maintenance for new road projects. Furthermore, the two main economic benefits of toll roads are time saving as well as energy saving. Evidently, a study (Munroe 2006) has shown that toll users do benefit a lot from the travel time saved. That is, based on his analysis he concluded that the estimated economic benefit of time saving from TCA’s toll road is at least $182 million per year. Additionally, Duff and Irvine (2005) elaborated that road user charges can promote economic efficiency and fairness. That is, the drivers who choose to use the road will value their use of the road system at an amount equal or greater than its cost. And on the other hand those who value the road system at an amount less than its cost will prefer not to drive. Hence, this is going to prevent wasteful allocation of scarce resources to a use for which people are unwilling to pay and it reflects the idea that who shall pay will use. Taking into account, the evidences of the success of Road pricing system in various countries, Baichoo and Baichoo (1999) summerised the advantages of an Automatic Road Pricing System as congestion reduction, a measure to generate revenue and under the environmental aspect as air pollution reduction. In order to know the public opinion about toll roads, several surveys were conducted. For instance, Kockelman and Kalmanje studied the Credit Based Congestion Pricing and the public opinion in several journals. Hence, Kockelman and Kalmanje (2005) conducted a survey to assess public opinion about a new policy called Credit Based Congestion Pricing (CBCP). CBCP is revenue neutral policy where generated tolls are returned to drivers in a uniform way, consequently, average divers happens to pay nothing and long distant drivers do pay. Their survey was based on a sample of 500 individuals where, 25 percent supported the policy. Oswald et al (1995 cited Podgorski and Kockelman 2005) tried to study the Tolling finance and application through a mail out mail back survey. Hence, they found that the use of toll revenues to improve non tolled facilities was acceptable. In addition, Podgorski and Kockelman (2005) elaborated in his journal that Wilbur Smith (FHWA 2002) as well as Pacific Rim Resources’ (2001) conducted telephone survey to know about the respondents who were willing to use toll roads and they were keen to support toll roads as a means to save time. There has been a lot of literature on pricing policies which were basically based on economics aspects. However, Tillema et al. (2003) stated that that the literature really done much research on the spatial consequences and they explained the importance of accessibility between the transport system and the land use system. 2.3.2.3 Critics of toll road Several studies were done to elaborate on the different risks facing toll roads. Sihombing et al. (2011) based his study in literature; he divided toll road infrastructure risks in Indonesia into nine parts: private equity risks, financial risks, economic credit risks, planning risks, design risks, procurement risk, construction risks, operational risks and concession risks. . Evidently, Fisher and Babbar (1996) studied the challenges related to private toll roads through the experience of eight privately financed toll road projects and found that the public sector was generally responsible for the political and revenue risks whereas the private was responsible for the project risk. Baichoo and Baichoo (1999) tried to explain the major issues related with Road Pricing System and elaborated that it can become a serious problem for low income earners as it would result in an increase of their expenditure; also this is not going to cure congestion but only shift the congestion problem from motorway to side roads. Hence, in his paper he proposed a pilot project in Mauritius so as to minimize the financial risks. Taking into account limited budgetary resources, Jamaica used the deferred financing facility as solution to finance road infrastructure (Spencer, 2007). Deferred financing refer to a financing facility where contractors are paid when the projects are completed. However, Spenser (2007) criticize that deferred financing has caused the Debt level to increase in Jamaica, resulting in a worst government deficit. The transport infrastructure sector has not been spared by the current crisis period (Tanaka, et al., 2005). The worsening Economics condition has caused many road projects to fail resulting in an increase in the level of risks. Consequently, the private financing of road projects has decreased in developing countries, so Tanaka, et al. (2005) used the Value-for-Money (VTM) methodology to assess and evaluate the risk in private finance projects. However, the VTM methodology was criticized as it lacks transparency. Government intervention is very important in private toll roads to be able to mitigate the level of risks during the project lifecycle (A.El-Amm, 2003). He summarized the risk mitigation strategies as a four “s” strategies namely; shape the risk, share the risk, shed the risk and sustain the residual risk, where he mentioned making use of hedging tools. http://ops.fhwa.dot.gov/freight/freight_analysis/improve_econ/appa.htm#s13 http://www.whitehouse.gov/sites/default/files/infrastructure_investment_report.pdf http://motors.mega.mu/news/2011/07/09/views-infrastructure-development/

HCS 472 University of Phoenix Week 1 Healthcare Marketing Reflection Paper

HCS 472 University of Phoenix Week 1 Healthcare Marketing Reflection Paper.

Assignment ContentHealth care marketing requires a different approach than other industries. In this assignment you will review current health care marketing and how it has evolved in the past 50 years, Think about what impact competitive, regulatory, technological, and environmental changes have on health care marketing.Research the following:Identify different events or shifts in our health care system within the past 50 years that have led to a change in health care marketing.Identify marketing ads for one health care-based company Select 1 marketing ad for a health care-based company from the past 50 years.Write a 350-word reflection that details the changes in health care marketing that have occurred in the past 50 years and why these changes occurred. Your reflection should:Describe how health care marketing has changed since the 1970s.Describe current health care marketing.Identify advantages of health care marketing for an organization and its consumers.Discuss whether you consider marketing an appropriate practice in health care.Consider readings related to the 4Ps of marketing.Identify how you think health care marketing will change in the next decade. Cite 2 peer-reviewed, scholarly, or similar references.Format your assignment according to APA guidelines.Submit your assignment.
HCS 472 University of Phoenix Week 1 Healthcare Marketing Reflection Paper

UOP Success of Caterpillars Global Approach to Change Management Case Study

assignment writer UOP Success of Caterpillars Global Approach to Change Management Case Study.

Hi there 🙂 Here’s the part 4 of what we’ve been working on for the last 3 weeks. 1.Review the Strategic Management Project Background document.Review the following terms and concepts discussed this week to prepare for this assignment:vertical integrationtaper integrationbackward vertical integrationforward vertical integrationstrategic alliancesglobal strategyinternational strategyinnovationCreate a Word doc and title it Strategic Management Research Journal Part 4.Write a 525- to 700-word response to the following prompts in your journal entry:Identify Caterpillar Inc.’s short-term and long-term goals.Evaluate how mergers and acquisitions in the last 3-5 years have contributed to Caterpillar Inc.’s performance and affected its organizational goals. Determine the most critical merger or acquisition that has contributed to Caterpillar’s performance and success in achieving organizational goals. Defend your choice.Evaluate the effectiveness of Caterpillar’s operational plan for global strategies (international, multi-domestic, global-standardization, or transnational). Include supporting research or data.Note: You will use information from this entry in your presentation due in Week 5.References: List a minimum of 2 references researched for this Journal assignment.Thank you!
UOP Success of Caterpillars Global Approach to Change Management Case Study

Ottawa University Winmark Corporation and Data Analytics Discussion

Ottawa University Winmark Corporation and Data Analytics Discussion.

Many companies and placement agencies require candidates to have knowledge about Excel as part of their recruitment process. Knowledge of Excel is useful in several fields in various industries, especially data analysis. Read the assigned chapter for the week. Come up with a use case for the concepts covered using real-world data for a business or organization.In the discussion forum, post a brief explanation of your data, the business or organization, and the use case in the appropriate forum of the message board. You cannot use the same business or dataset as one of your peers. If you are uncertain of the data or organization to use for this assignment, use the discussion forum to brainstorm with your peers.Once you have chosen a data set and organization, create an Excel file in which you apply functions to demonstrate the use case. On a separate sheet in the Excel file, write a brief overview and summary in which you:Provide an overview of your data, business/organization, and use caseAnalyze the data and give reasoning of why you think it is useful to the business or organization.Articulate what Excel functions you have used and apply it to the dataset to demonstrate it.Using this function Charting Tricks
Ottawa University Winmark Corporation and Data Analytics Discussion

Rammed Earth As A Low Impact Building Environmental Sciences Essay

Rammed earth is widely used as a construction material from past many years. It is a monolithic type of construction which is built by compacting successive layers of soil. Rammed Earth as a material has a wide range of advantages and utilizations. So, an approach to explore the rammed earth construction in temperate climate of India by understanding the techniques and methods of construction, the properties of the material and the use of rammed earth in from past till present as well as in future in described. The essay is a brief study of the material, its history, technology, climatic response, feasibility and stand in today’s construction era. Experimental data have been included. 1. INTRODUCTION SUSTAINABLE BUILDING The sustainable building technology has seen a recent jump in interest in recent times. The rise in Global Warming has led Governments, to take speedy measures, to execute more environmental friendly practices. The government of UK has set up plans to reduce impact on earth by 60% by the year 2050 (DTI, 2007). Currently, the buildings in Europe contribute to 25-40% of the energy used by the society (UNEP, 2007). The energy used in a building can be summarised by, the embodied energy of material, the energy spent in transportation, that used in construction, the energy consumed in the use of building and lastly, the energy used in disposal of the building at the end of its life. This energy consumption can be reduced by using low impact material, which carries low embodied energy. The embodied energy contributes to 10% of the total energy consumed by the building (UNEP, 2007). The use of locally available material can reduce the transportation energy. Different environmental building technologies, such as passive design for buildings can be used to reduce the energy in use of the buildings. Thus the use and study of low impact building material has gained importance. SUSTAINABLE MATERIALS Sustainable materials have been used through centuries, but the environmental building technology, which has come out of the current environmental restraints, has set the revival of the old environment friendly materials. The locally available materials, which can be used without spending energy on transportation, manufacture of materials and even processing of raw materials, prove more economic, for energy consumption. Industrialised construction causes a lot of pollution. Thus the alternate methods of construction, viz, abode, rammed earth, stone, straw bale, hemp-lime, bamboo, cob, wood, earth-bag, wattle and daub among others. The traditional building methods have employed use of the natural materials in the past. Now, these materials and technologies, through study and experiment, are being reinvented, for efficient sustainable low impact use. Rammed Earth is one such material which is being revived as a low impact building material. The significance of this material in the history of architecture is worthless. Michael Crichton, an author describes, “If you don’t know history, then you don’t know anything. You are a leaf that doesn’t know it is part of a tree. ” This essay is an opportunity, to learn about the vernacular and modern use of Rammed earth. As rammed earth construction is found in different climatic zones, it also brings the necessity of considering the material’s relation with various climate types. It is important to study the properties, techniques (both vernacular and modern) of building in load bearing and framed construction and also their response to climate and geographical context.” This essay explores Rammed Earth, as a low impact building material. The study of its historic social context and its appropriateness in today’s building scenario is also carried out. An analysis is made on the appropriateness of Rammed Earth, for contemporary architecture. RAMMED EARTH One of the oldest building methods, Rammed Earth is a (adjective) form of construction. Through centuries, this method has been used to build superior quality walls, which encompass the qualities a building should possess, viz. Strength, beauty and utility. Buildings made of rammed earth have stood strong for hundreds of years. In the past decade, the importance of rammed earth has considerably increased. In view of, the need of a more sustainable environment; as a material consuming less energy, yet providing a greater life span, ‘Rammed Earth’ is being re invented as another low impact, energy efficient building material. The Rammed Earth walls are made using materials of earth, namely, lime, mud, gravel, chalk, etc. These constituents are easily available on any land, and hence, the Rammed Earth construction has been found on all continents, except, the Antarctica. Its favourability to any climate and measure of strength are proved by the many ancient earth buildings which still exist, eg. The Great Wall of China, China. Many earth structures sit in the foot of the Himalayas. Earth heritage can also be found in the countries of China, India, France, Morocco, Spain, South America, and Europe. 1.2 RAMMED EARTH CONSTRUCTION Rammed earth walls are constructed by compacting soil in the formwork. Usually damp soil from the site is used directly, or sieved, to remove the larger gravels in the soil. This soil is then added with suitable proportions of stabilizers. Initially animal blood was used as a stabilizer, as opposed to the cement, asphalt or lime stabilizers of today. Straw is used as reinforcement, and mixed in the soil batches. A layer of soil of thickness 150mm is placed in the formwork and then compacted with rammers. Once this layer gets settled, other layers of same thickness follow. The required height can be achieved by moving the formwork upward as the layers settle. The wall hardens almost as soon as the form work is removed. Rammed earth takes 2 years to cure. It gains compressive strength as it cures. Thus the construction is best done in warm weather, so the walls can dry and harden. 1.3 PROPERTIES Dry density Strength (compressive, tensile, shear) Durability Shrinkage Surface finish Thermal insulation Advantages Distinct appearance Natural and readily available Low embodied energy (a level similar to brick veneer construction) Unstablised earth is reusable post-demolition High moisture mass, hygroscopic – helps regulate humidity Use of local soils supports sustainability practices. High thermal mass (though work is still underway to quantify its extent) Airtight construction achievable Traditional form of construction Modern methods are widely tried and tested overseas eg Australia Disadvantages Concerns over durability – requires careful detailing Poor thermal resistance – external walls require additional insulation Not all soil types are appropriate High levels of construction quality control are required Longer than average construction period Few modern examples exist in the UK – relatively untested in UK climate. High clay content can cause moisture movement. Structures may need to accommodate this. No UK codes of practice Adding cement stabilisation can compromise environmental credentials 1.4 STABILISED EARTH CONSTRUCTION Though rammed earth is considered a strongly sustainable material, it has some shortcomings in relation with durability. Some of the factors in natural earth which need improvement are, water resistance, shrinkage, external surface protection and strength. For overcoming this problem, stabilisers are used. In olden times, lime or animal blood were used to stabilise the material, while modern construction uses lime, cement or asphalt emulsions. Some modern builders also use bottles, tires, or pieces of timber. Though stabilisers add to the carbon emission and thus the negative impact to some extent, they reduce uncertainty and risk. Hence, they are used. The most common stabiliser used is cement. It generally makes 6 to 7% of the total mixture. Characteristics of Stabilised Rammed Earth STRENGTH Strength of unstabilised Rammed Earth is 1MPa and that of stabilised Rammed Earth is 10MPa. Stabilised Rammed Earth is suitable for both load bearing and framed structure. FIRE SAFETY Earth is a non-combustible material. Rammed Earth walls can sustain fire for 9 hours. RESISTANCE TO MOISTURE Earth walls can control humidity. Unclad internal walls can hold humidity 40% – 60% which is suitable for asthma patients, and storage of books. SOUND INSULATION Rammed Earth is effective for insulation. The design should accommodate provision of cavity walls for better sound separation. CONSERVATION OF FUEL AND POWER U-value of 300mm earth wall is ‘H 1.5 – 3 W/m2K, therefore insulation needs adding in external wall applications. MATERIALS AND WORKMANSHIP Material adequacy can be found out by sampling, lab testing or precedence. The quality of workmanship can only be derived against specification, test panels, etc. 1.5 DESIGN ISSUES STABILISED RAMMED EARTH walls need added protection. Hence additional measures are required to be taken while designing rammed earth construction. 1.51 INSULATION As discussed earlier, rammed earth has some shortcomings. Rammed earth has poor thermal performance, in some areas. Here, extra insulation is required. Earth walls breathe. They absorb moisture and then let it evaporate. Rammed earth is hygroscopic. Wherever walls have external cladding, the cladding systems should be vapour permeable. It is wise to consider vapour permeable walls for both unstabilised and stabilised walls, to reduce condensation build up on the inside face of insulation. When moisture is allowed to escape from the external face, the permeability is of less concern while specifying internally applied insulation. External Insulation Wall needs to be protected from weathering. Thermal mass should be exposed internally. Some types of insulation renders are described below. Insulating render rammed earth with insulating render Figure: showing insulation Source: http://www.greenspec.co.uk/rammed-earth.php. Insulation Board and Render rammed earth and insulation board and render Figure: showing insulation Source: http://www.greenspec.co.uk/rammed-earth.php. Insulation materials: breathing insulation: cellulose slab, composite wood wool board (not cement-based), wood fibre board, cork, hemp, and hemp-lime. Render: limecrete, mineral render, plaster, proprietary permeable renders. Rain screen Cladding rammed earth and rainscreen cladding Figure: showing rain screen cladding Source: http://www.greenspec.co.uk/rammed-earth.php Insulation materials: breathing insulation: cellulose slab, composite wood wool board (not cement-based), wood fibre board, cork, sheep’s wool, hemp, and hemp-lime.Cladding: wood, tiles, slate, board and polymer-based render, proprietary cladding systems. B) INTERNAL INSULATION In case of internal insulation, the natural look of the exterior is maintained, but the available thermal mass on the inside is lost. rammed earth internal insulation Figure: Free standing studwork with infill insulation. Source: http://www.greenspec.co.uk/rammed-earth.php. Insulation materials: Cellular glass, Mineral wool slab, expanded polystyrene, Phenolic foam, Polyisocyanurate (PIR), Polyurethane (PUR). 1.52 WEATHER PROTECTION Protection Given By the Roof rammed earth overhanging eaves Figure: The eaves provide protection from rain. Source: http://www.greenspec.co.uk/rammed-earth.php. Footings and Base rammed earth footing and base Figure: The DPC should be finished flush with the wall surface to avoid splash. Source:http://www.greenspec.co.uk/rammed-earth.php 2.0 HISTORICAL USE “Archaeological evidence can date entire cities constructed of earth back over 10,000 years. All of the great civilisations of the Middle East were constructed with mud brick and rammed earth – Assyria, Babylon, Persia, and Sumeria. Rammed earth construction was used to construct countless monuments, temples, ziggurats, churches, and mosques. Many of these structures (the Great Wall of China being one) have stood the test of time and are still standing today.” Rammed earth construction originated in China, in the Neolithic age. Rammed Earth remains have been found in the archaeological sites of Yangzhou and Langham cultures of the yellow river valley, dating back to 5000 BC. By 2000 BC, the use of this material spread across china. Rammed Earth was commonly used for building walls and foundations. The 4000 year old, Great Wall of China has also been originally constructed in Rammed Earth, known there as ‘Taipa’. Its outer covering of stones and bricks, made later, gives it an appearance of stone wall. Foundations dating 5000BC have been discovered in Assyria. The core of the sun pyramid in Teotihuacan, Mexico, built between 300 and 900 AD, consists of approximately 2 million tons of Rammed Earth. Rammed Earth developed as a construction technique in various parts of the world independently. It had great influence in the Middle East Countries, China and Europe. It also became popular in Africa and America. The Romans built many earth structures throughout Europe. 2.1 GLOBAL DISTRIBUTION The early human shelters were caves. So, the use of earth construction is believed to have started as extensions to caves, such as mounds of earth at cave entrances, or cut earth, etc. The Rammed Earth building technique developed in several places independently. Man spread its use to different locations with his travelling for hunting. Rammed Earth structures are made from soil removed from the ground. The soil which has appropriate proportions of clay soil and sandy silt, is suitable for construction. The regions with abundance of such soil make use of earth construction. This soil with silt, sand and clay together is found in various locations, but is usually found in hilly areas, edges of large river valleys, mountainous regions with glacial tilt. The Himalayan ranges have many still existing examples of Rammed Earth structures. Ladakh, Bhutan, Nepal are regions where Rammed Earth practices were popular. Rammed Earth continues to be promoted in the country of Bhutan. Traditional Rammed Earth was prepared by ramming natural soil in small batches in a vertical formwork. The regions, which cannot provide soil favourable for preparing sun dried clay bricks, or timber; made use of rammed earth as a construction material. The desert sections of the Great Wall of China, Potala Palace in Lhasa, are made of Rammed Earth. Rammed Earth was also used to build fortification in North Africa and Spain. In Europe, rammed earth technology was used in vernacular style in the late middle ages, and continues to be used in Africa today. 2.2 METHOD OF CONSTRUCTION http://www.historicrammedearth.co.uk/indian_rammed_earth.png Soil was removed from the ground and used for construction. It was sieved if found necessary. Straw and lime, mixed into the soil, were used as additives to increase the strength of structure. The soil was then dropped into a formwork in layers of 150mm high. The layer is compacted using heavy rammers. On compaction of one layer another layer is laid and the same procedure is carried out, till the formwork is full. The formwork is then moved vertically to accommodate more earth. Once the formwork is moved vertically, the horizontal timbers are removed from the wall, leaving characteristic holes. Figure: Urdu manuscript showing Rammed Earth Construction. Historic Formworkrammed earth formwork Formwork is made up of timber sides. These are held together by vertical timbers connected to horizontal timbers which go through the wall. This formwork design is found in Nepal and Morocco. In some places, stones are placed over horizontal timbers to allow their removal. The traditional rammed earth wall can thus be constructed with little labour and without recourse to temporary works. Figure: Rammed Earth Formwork 2.3 MODES OF FAILURE AND REPAIR TECHNIQUES The strength present in unstabilised earth construction, also owes to a less understood phenomenon of suction. The pressure difference between air and water components of soil creates the interface of water and air to curve. This curve accommodates pressure difference, bringing about surface tension. The combination of surface tension and pressure difference creates a strong attractive force in the pores, thus strengthening the soil wall structure. (Jaquin P.A.) A study on failures has been made extensively by Paul Jaquin of Durham University. Considering failure mechanism of historic structures can be utilised in taking measures for rectification and prevention for future. Cracking is the main mode of failure in Rammed earth structures. A study of presence of water, for strength is also important. Water A small amount of water can add strength to the structure. Excess of this water can also lead to failure. In the later case, structure becomes saturated, loses strength, then integration and finally leads to complete destruction of the building. When a structure is not maintained, Water enters a building. It can enter the wall when the roof is open. Slurry is formed on the top of the wall and the material moves downward, leading in complete erosion of the wall. The water flows through the walls and evaporates through the surface, leaving precipitated version of salt in the pores. This salt expands and cracks the pores and leads to removal of fine grained surface. Use of permeable cement covering on the surface is not recommended, as water gets trapped and movement might occur. Use of less permeable material like brick wall also poses danger, if the water level increases leading to loss of structural integrity. The use of masonry to protect earth walls had been used in China and Spain to protect walls from the threat posed by artillery. Cracking: Cracks are formed in walls due to unsaturation of soil. The tensile stress in soil is less, which leads to this unsaturation. Crack Stitching: As a treatment to the cracks formed in buildings, crack stitching is applied. This method is applied with utmost care, so as to not induce any more stresses in the cracks. Hence ‘Soft Stitching’ is practiced. This involves application of similar material across the crack. This provides similar stiffness to the material, and thus works well in repair of large cracks in earthen structures Crack stitching was carried out for a monument in Ladakh, India, by Jogn Hurd in 2004. The technique he used is as follows. A buttress is placed at the base of the slope. Soft ties are introduced across the crack to create structural integrity. A mud brick staple is constructed across the crack, to half the thickness of wall. Part of the staple is cut and hemp matting placed inside the cut. Mortared sundried bricks are then placed within the cut, forming a solid staple wall. Seismic Protection: Rammed Earth is constructed in horizontal layers. Once one layer is complete, the formwork is raised upward for another layer. Every layer is known as a lift. Historical evidence shows that materials such as, straw, lime, stones, brick are placed between lifts. These materials act as tie beams across the walls, tying them together and thus help in seismic protection (Hurd,2006). In some sites of Spain built in 1504, lengths of timber were placed in the wall while ramming. Their appropriate placement, proves an understanding of seismic design. These timers were first made circular, then covered in a lime and straw mortar, which was then rammed within the wall. These timbers were placed at 1.6m intervals, in a ring, throughout the building. 2.4 EXAMPLE C:UsersVarunDesktopbasgo1.jpg Figure: showing castle made of rammed earth at basgo, India. Source: http://www.historicrammedearth.co.uk/india.htm “The site at Basgo consists of four distinct structures, three temples and a fort. The fort (Basgo Rabtan Lhartsekhar Castle) was built first and is the only structure made from rammed earth. The rammed earth section stands in the centre of the site, and consists of a mainly ruined set of walls, with no roof structure. A large crack is visible in the face of one of the walls which were repaired by in 2000. The castle withstood a three year siege in 1684, but may have been destroyed by invading Sikhs in around 1819 and definitely by 1843”. 3.0 CONTEMPORARY USE The Rammed Earth construction received worldwide interest, owing to its non dependency on materials such as cement, ease of availability, and potential for recycling. The most important factor for its resurgence is its sustainable longevity. Rammed Earth is now being treated as a structural material and rules for designing have developed accordingly. In the 15th century, rammed earth was brought to Europe. The 19th century, America saw resurgence of Rammed Earth as a construction Technology. The book ‘Rural Economy, by S.W. Johnson popularised it in the states. The famous historic landmark, ‘Burough House Plantation’ in 1821, is the largest complex of built Earth in the US. After 1920, for almost 30 years government spent a lot of money on research of Earth structure construction. It even built low cost houses which became very successful. But, after WW2, the use of earth as a building material declined as modern building materials and technology were available at economic rates. Contractors and engineers found modern construction easier. Thus, use of rammed earth declined. 3.1 GLOBAL DISTRIBUTION The modern era of Rammed Earth can be seen particularly in California, Western Australia and UK. Australia has rich granite deposits and lateritic soils, suitable for construction of Rammed Earth. The property owners find all suitable material on their site itself, or nearby. This type of construction proves to be economical and long lasting. Thus the popularity grew in Australia. The technique has observed growth in the southwest, around Tucson, Arizona and Las Cruces and Albuquerque, New Mexico, California, Colorado. 3.2 METHOD OF CONSTRUCTION The method is similar to historic construction at large. All the old practices employed unstabilised earth, rammed on a raised masonry stem, protected by roof hangings. Today, concrete is used in the structure. A concrete stem must project 6inches above grade. Foundations are in the shape of an inverted T. In some places, rubble filled trenches are packed with reinforced concrete beam 10 inches thick and wider than the wall, to hold the ledges. Earth material is stabilised using Portland Cement in the weight of 5%. Softer earth plaster, stabilised with asphaltic emulsions, is used to clad unstabilised earth walls. The formwork, now famous as concrete forming panel, is made of sturdy steel frame and special plywood inset, suited for rammed earth. Pneumatic ramming is used instead of the ancient hand ramming. The strength obtained by both is same. 3.4 EXAMPLE C:UsersVarunDesktopCAMR2FM1.jpg Fig: Rammed earth house in Bangalore, India. Source :http://rammedearth.blogspot.co.uk/2007/09/rammed-earth-in-india.html “This is home was designed by Chitra Vishwanath Architects for Nishwath Hassan and Prakash Iyer, a Bangalore-based couple in their mid-30s. The walls are 9″ thick. They have sufficient self-weight to not need any other attachment or reinforcement. There is a nice rich mud mortar between the plinth beam (there’s a beam above the stone foundation) on which the bricks rest and then the rammed earth. The bricks or mud blocks can be optionally done away with. The self-weight of the wall structure is sufficient to hold it in place. In India we always have built in brick, stone and cement and reinforced cement concrete. Except for the roofs, beams and concrete columns (if there are any) steel is not used to reinforce walls. Our structural engineers say it’s not necessary. The load bearing capacity of the RE walls or any wall is dependent on their own strength and by self-weight they hold well in placeThe soil that was excavated from the basement was used to build the house. It was mixed by hand with sand and 5% cement then transported without the use of machinery. Its important that the design makes way for hot air (vertically up) and brings light into the right parts without using humungous openings. Helps in controlling cost of structure too. These Ecological homes that we make are cheaper than the conventional designer homes in the same city” 4.0 APPROPRIATENESS OF RAMMED EARTH IN DIFFERENT CLIMATE TYPES The behaviour and function of rammed earth structures depend upon the climate they are exposed to. Rammed earth is an ideal choice for climates with distinct variation in day and night temperatures. Rammed earth is generally found in dry climates eg. Mediterranean rim, through central Asia and in parts of China and Himalayan regions. Whereas in tropical climates where the difference between day and night time temperatures is not much, Rammed earth does not work well. Although Rammed earth does not work well in excessively humid climates, evidence show that rammed earth structures can withstand severe rainstorm and snow fall for a short duration. A brief overview of different climates is given below. Temperate Climates Rammed Earth is placed in parts exposed to sunlight. The special properties of rammed earth alloy it to store the heat from the day, and release it at night, thus providing warmth. In these regions, walls are insulated to prevent heat loss. Hot, Arid Climates Buildings of high thermal mass work potentially here, in the deserts. The wall retards the passage of heat from the external face to the internal face. It even radiates the heat gained in the day time, back at night. Hot Humid Climates Night temperatures remain elevated in this environment, thus challenging the strength of rammed earth. rammed earth is placed away from direct sunlight so that it does not gain extra heat, as it will get overheated. 5.0 Tropical climate 5.1 Impact of climate 5.2 Local Availability of RE 5.3 Other uses of RE 5.4 Other factors deemed of interest. Use http://www2.cemr.wvu.edu/~rliang/ihta/papers/11 FINAL Paul Jaquin_paper_workshop.pdf 5.5 Vernacular style in temperate climate. 5.6 Whether it has been low impact Page 12 lax 5.7 Whether it is suitable for the climate 5.8 Which other materials are suitable for temperate climate. 6.0 Conclusion Appropriateness in Contemporary architecture. The likely future for the application of rammed earth is as: – Thermal mass. – Internal load-bearing unstabilised walls. – External load-bearing stabilised walls. (ref. Jaquin P.A. http://www.historicrammedearth.co.uk/Rammed_earth_structural_engineer.pdf) ( http://www.historicrammedearth.co.uk/india.htm) ( REF: http://www.greenhomebuilding.com/pdf/buildingstandards_sepoct98_ramearth.pdf) (Ref: http://www.rammedearthliving.com.au/index.php?option=com_content