457 research outputs found
Visualizing Interior And Exterior Jet Aircraft Noise
In today\u27s competitive aerospace industry, the quest for quiet has drawn significant attention to both the interior and exterior design of an airplane. Understanding the noise generation mechanisms of a jet aircraft is a crucial first step toward developing the most cost-effective noise and vibrations abatement methods. In this investigation, the Helmholtz Equation Least Squares (HELS) based nearfield acoustic holography will be used to understand noise transmission caused by jet engine and turbulence into the fuselage of a jet aircraft cruising at 30,000 ft.
Modern propulsive jet engines produce exterior noise sources with a high amplitude noise field and complicated characteristics, which makes them very difficult to characterize. In particular, there are turbulent eddies that are moving through the jet at high speeds along the jet boundary. These turbulent eddies in the shear layer produce a directional and frequency dependent noise. The original HELS approach assumes a spherical source at the origin and computes the acoustic field based on spherical emission from this source. This assumption of one source at the origin is not sufficient to characterize a complex source like a jet. As such, a modified HELS approach is introduced that will help improve the source characterization as it is not dependent on a single source at the origin but a number of virtual sources throughout the space. Custom microphones are created to take acoustic pressure measurements around the jet engine. These measured acoustic pressures are then taken as input to the modified HELS algorithm to visualize the noise pattern of a subsonic jet engine
Betul Districts Primary School Performance Prediction Model Using Data Mining
As this academic performance is influenced by many factors, it is essential to develop predictive data mining model for studentsā performance so as to identify the slow learners and study the influence of the dominant factors on their academic performance. In the present investigation, a survey cum experimental methodology was adopted to generate a database and it was constructed from a primary. While the primary data was collected from the regular students and irregular student the secondary data was gathered from the school in class 3, 4 and 5 a total of 1000 datasets of the 2014 year from five different schools in three different districts of BETUL state Madhya Pradesh were collected. The raw data was preprocessed in terms of filling up missing values, transforming values in one form into another and relevant attribute/ variable selection. As a result, we had 700 student records, which were used for primary school prediction model construction. A set of prediction rules were extracted from primary school prediction model and the efficiency of the generated student prediction model was found. The accuracy of the present model was compared with other model and it has been found to be satisfactory
Thermoelectric generators
As the world is changing and developing with every passing day, the requirements of power are also increasing. There is a shift in utilizing the electrical energy as much as possible and for this reason, many countries have already made policies for completely ruling out the machines which donāt run on electricity. Apart from electricity, there are other forms of energy that can be used to convert that form into a more desirable form. For example, in a plant where the smoke comes out of the chimneys or in a car, the smoke carries a large amount of thermal energy with it. This energy is nothing but a waste and reduction in the efficiency of the systems. If somehow, this energy could be recovered, the efficiency can be increased. Thermoelectric generators serve for this purpose. Thermos electric generators get the heat and using the principle of heat conduction and p and n type materials, the heat can be directly converted into the electricity. There are many materials available in the market for p and n type but in our case, we chose silicon germanium which is also one of the most commonly used. First of all, a single module of thermoelectric generator will be made using p and n type material, as well as using conductive material and some ceramic substance. Then, the entire assembly will be made and this assembly will be exported to Ansys where custom materials will be added and applied on to the geometry. After performing analysis on full model, a comparative study will be presented in which the effect of material of conductive plate on to the voltage difference will be studie
Efficient K-Mean Algorithm for Large Dataset
The term data mining is used to discover knowledge from large amount of data. For knowledge discovery many software haven developed, that is known as data mining tools these are statistical, machine learning, And neural networks. K-means and K-medoids are widely used simplest partition based unsupervised learning algorithms that solve the well known clustering problem. The procedure follows a simple and easy way to classify a given data set through a certain number of clusters; technically, data mining is the process of finding correlations or patterns among dozens of fields in large relational databases. Stored data is used to locate data in predetermined groups called class. Data items are grouped according to logical relationships or consumer preferences called cluster. Data can be mined to identify association. Data is mined to anticipate behavior patterns and trends called sequential patterns
Fuzzy Controlled SVC for Reactive Power Control of Long Transmission Lines
Flexible AC transmission system (FACTS) devices are used to improve the existing transmission capabilities of the transmission system by making it more flexible and independent operating. The technology is used to achieve complete deregulation of power systems i.e generation, transmission and distribution. The loading capability of transmission system can also be enhanced nearer to the thermal limits without affecting the stability. The closed loop smooth control of reactive power can be achieved by using shunt connected FACTS devices. Static VAR Compensator (SVC) is one of the shunt connected FACTS device which is to be utilized here for the purpose of reactive power compensation. This paper attempts to design and simulate the Fuzzy logic control which is used to regulate the firing angle of SVC. With this scheme, it is seen that a better, smooth and adaptive control of reactive power has been achieved. The modelling and simulations are carried out for 750km long Transmission line and the compensation is placed at the receiving end (load end). Keywords: Flexible AC transmission system (FACTS); Static VAR Compensator (SVC); Fuzzy Logic Controller (FLC)
Spleen rates and infant parasite rates as surveillance tool for malaria control in remote hard to reach areas of central India
<p>Abstract</p> <p>Background</p> <p>Malaria due to both <it>Plasmodium falciparum </it>and <it>Plasmodium vivax </it>is a major public health problem in India. The quantification of malaria transmission for the classification of malaria risk has long been a concern for epidemiologists. Results are presented from 30 cross-sectional surveys which measured spleen rates (SR) and infant parasite rates (IPR) in the forested districts of Madhya Pradesh during malaria outbreaks to assess whether both IPR and SR can still be used as indicators of malaria endemicity as spleen examination has lost much of its value as an epidemiological indicator in areas where anti-malarials drugs are widely used.</p> <p>Methods</p> <p>Rapid fever surveys were carried out from door to door and all suspected malaria cases in the entire population of a village were screened for malaria parasites on the basis of clinical symptoms such as fever, chill, rigor, headache and body ache etc. Children between 2 and 9 years were examined for enlarged spleen according to Hacketts method. Finger prick blood smears were collected from all children with enlarged spleen with or without fever after obtaining written informed consent following institutional ethical guidelines. Infants less than 1 year were also screened for malaria with or without fever.</p> <p>Results</p> <p>Since malaria is local and focal, in some areas the outbreak waned quickly in few months and in some areas continued for 3 to 4 years. The analysis of trend revealed that when IPR decline over the years as a result of malaria intervention measures, SR also decline. In case splenomegaly continues without diminution in size, it is probably due to recrudescence or relapse, although it is not possible to separate malaria parasite species on the basis of SR.</p> <p>Conclusion</p> <p>Both the tools are of immense value in evaluating and assessing the malaria situation especially in remote areas where sophisticated molecular and serological techniques are difficult to establish. Therefore, in forested areas malaria surveillance system will require adoption of multiple approaches that have proven effective now or in the past.</p
Comparison of safety of loteprednol 0.5%/difluprednate 0.05%/prednisolone 1% eye drops in the post cataract surgery patients
Background: Post surgical ocular inflammation is a common happening after the cataract surgery. Topical steroids are the main stay of the treatment. Although it is quite effective in controlling it but it produces severe adverse drug reactions i.e. rise in intraocular pressure and dryness in the eyes. In present study we have compared the two newer topical steroids i.e. loteprednol and difluprednate with prednisolone for the safety issue.Methods: Total n=150 patients of cataract were enrolled in the study. Institutional ethics committee approval was taken. After randomization, patients were allocated into three groups of 50 each. Baseline reading of intraocular pressure and tear film breakup time was recorded. Post operatively examination was done on day 7, 15 and 30 day. The results were compared as prednisolone versus loteprednol, prednisolone versus difluprednate.Results: A. On intraocular pressure 1.prednisolone versus difluprednate statistically significant effect at day 7 (p=0.043), day15 (p=0.010) and at day 30(p=0.036) were there. 2. Prednisolone versus loteprednol- The difference was statistically highly significant at day 7 (0.00), day 15 (p=0.009) and at day 30th (p=0.00). Ā B. On tear film breakup time-No significant effect on tear film breakup time is observed.Conclusions: Both the newer drugs are much safer as compared to prednisolone for intraocular pressure. As they are equiefficacious to prednisolone their use in post cataract surgery inflammation is recommended
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