Thermodynamic Cycle Analysis Coursework Example | Topics and Well Written Essays - 1500 words

Thermodynamic Cycle Analysis - Coursework Example 2. You should set the initial conditions (green boxes) to reasonable values, explaining your choices. You should also explain the effects that increasing or decreasing these values have on the model. The initial conditions for density of air, ambient pressure, and ambient temperature for the engine have been input in the relevant green boxes in the excel file. The air pressure at sea level is 1.225 kg/m3, rounded off to 1.2 kg/m3 (Ahrens et al. 2012). This is at a temperature of 15Â °C (The Engineering Toolbox 2013). This air density is chosen because it is the density of air present at sea level. The ambient temperature is set at 300 K because this is generally taken as the average room temperature. The ambient pressure is chosen as 1.000 bar because the standard atmospheric pressure is generally indicated as 1 bar, which is equated to 100,000 Pa (Ahrens et al. 2012). Air density affects the pressure in the cylinder, ambient pressure affects the power generation and ambient tempera ture affects the efficiency of the engine. The effect of increasing the given value of air density would be that the pressure in the cylinder will increase for the compression ratio mentioned in the table. There will be more air to mix with fuel if the air density is high and therefore, there will be more power. Increase in the pressure at the same temperature will result in increase in power generation. Increasing the given value of ambient pressure will cause an increase in the maximum pressure in the cylinder. This will in turn increase the power and torque of the engine and vice versa. At low pressure, the air per cubic meter is lesser due to lesser pressure. This will lead to a reduction in performance of the engine. This effect is dependent on the speeds, as shown by Shannak and Alhasan (2002). At a low speed of up to 2500 rpm, volumetric efficiency and fuel consumption of the engine are found to decrease at with decrease in ambient pressure. On the other hand, at a higher spe ed of 3000 rpm, engine performance is found to decrease with increase in atmosphere pressure. Furthermore, while it can be assumed that at higher pressure the power and torque of the engine increases, there are more structural loads on the car and the fuel consumption is also increased (Ayers 1997). If the ambient temperature is reduced, the efficiency of the engine will increase. Increase in the ambient temperature results in a reduction in the engine efficiency as well as output (Energy and Environmental Analysis, Inc. 2008). All engines are known to have a better performance at lower temperatures (Ayers 1997). This will happen because reduction in ambient temperature will cause a higher energy transfer to the crankshaft. Thus, the energy loss will be reduced and the engine will have higher efficiency. 3. You now need to select suitable values for the polytropic index for compression and expansion (pink boxes) explaining your choices with reference to adiabatic, isothermal and pol ytropic processes and the differences between them. The suitable values for the polytropic index for compression and expansion have been input into the relevant pink boxes in the excel file. The values are given as 1.3 and 1.2 respectively for polytropic index of compression and polytropic index of expansion. The polytropic index of compression for petrol engines is generally reported as 1.3 (Huleihil and Mazor 2012). A polytropic index of 1 is considered isothermal while that of 1.4 is considered adiabatic (The Engineering Toolbox 2013). In our engine, the

Strategic Accounting Assignment Example | Topics and Well Written Essays - 2500 words

Strategic Accounting - Assignment Example Quality costing should therefore be understood as the cost of not producing a product, which bears the above components that gauge a quality product or service (Thompson, 2010). The aspect of quality cost arises from the third era of quality where it emerges as a tool of quality assurance with its main goal being to avoid problems, by giving room to coordination of activities. Quality control as a technique of management accounting has been improved over time through the contribution of various scholars, who added in more knowledge and insight to quality control. Crosby initiated the aspect of quality testing through inspection, quality management, quality assurance and improvement (Kilger, 2002). Deming on the other hand shared his contribution by introducing the aspect of companywide quality control, which was later revised by Juran through his total quality management technique (Nokes, 2000). Quality costs are mainly understood in four major groupings which are commonly referred t o as the four types of quality costs. Prevention costs is a type of quality control and is considered as generally the most effective way to manage quality costs and avoid defects of products and services (Sadler, 2003). Prevention costs hold on a projection that it is better to prevent a defect from occurring at the first place than to correct it when it has already occurred, as it tends to be more expensive. Prevention costs make use of control activities such as statistical process control, quality engineering and training, which reduce defects. Prevention cost as a type of quality control also takes in activities relating to quality control, which consists of people who meet to discuss and solve quality problems. Statistical quality control as an activity of quality control is used to detect whether a specific product or service is in or out of quality (Samset, 2010). Prevention costs therefore take in the perspective of all activities that are designed to prevent the initial po or quality of products and services (Commission for local governance, 2000). Appraisal costs are also referred to as inspection costs and are incurred by an organization with the aim of identifying defective products in the production process, to make sure that defective products are not shipped to customers. Appraisal costs have the purpose of inspecting the production process and ensuring defective products are identified and eliminated. Many organizations however look at appraisal costs as expensive and ineffective to customers (Cadez, 2008). Other than employing appraisal costs, many companies encourage customers to be increasingly responsible for their own quality control through designing products that allow simple manufacturing, which gives a chance for quality to be built into the products (Morden, 2012). Internal failure costs on the other hand refer to cots incurred internally when a particular product fails to conform to design specifications that had been identified init ially. Internal failure