IJIRST : CALL FOR PAPER : 2019

#IJIRST - #International #Journal for #Innovative #Research in #Scienceand #Technology

Call for Papers | Vol. 5 Issue 11 - April #2k19

Last date of Paper submission 25th March '19 

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A Review on Thermal Insulation and Its Optimum Thickness to Reduce Heat Loss

Title:- A Review on Thermal Insulation and Its Optimum Thickness to Reduce Heat Loss

Author Name: Dinesh Kumar Sahu, Prakash Kumar Sen, Gopal Sahu, Ritesh Sharma, Shailendra Bohidar

Department of Mechanical Engineering

Kirodimal Institute of Technology, Raigarh (C.G.)

Abstract:- An understanding of the mechanisms of heat transfer is becoming increasingly important in today’s world. Conduction and convection heat transfer phenomena are found throughout virtually all of the physical world and the industrial domain. A thermal insulator is a poor conductor of heat and has a low thermal conductivity. In this paper we studied that Insulation is used in buildings and in manufacturing processes to prevent heat loss or heat gain. Although its primary purpose is an economic one, it also provides more accurate control of process temperatures and protection of personnel. It prevents condensation on cold surfaces and the resulting corrosion. We also studied that critical radius of insulation is a radius at which the heat loss is maximum and above this radius the heat loss reduces with increase in radius. We also gave the concept of selection of economical insulation material and optimum thickness of insulation that give minimum total cost.       

Keywords: Heat, Conduction, Convection, Heat Loss, Insulation

I.    Introduction

Heat flow is an inevitable consequence of contact between objects of differing temperature. Thermal insulation provides a region for insulation in which thermal conduction is reduced or thermal radiation is reflected rather than absorbed by the lower temperature body. To change the temperature of an object, energy is required in the form of heat generation to increase the temperature, or heat extraction to reduce the temperature. Once the heat generation or heat extraction is terminated a reverse flow of heat occurs to reverse the temperature back to ambient. To maintain a given temperature considerable continuous energy is required. Insulation will reduce this energy loss.

     Heat may be transferred in three mechanisms: conduction, convection and radiation. Thermal conduction is the molecular transport of heat under the effect of temperature gradient. Convection mechanism of heat occurs in liquids and gases, whereby the flow processes transfer heat. Free convection is flow caused by the differences in density as a result of temperature differences. Forced convection is flow caused by external influences (wind, ventilators, etc.). Thermal radiation mechanism occurs when thermal energy is emitted similar to light radiation.

      Heat transfers through insulation material occur by means of conduction, while heat loss to or heat gain from atmosphere occurs by means of convection and radiation. Materials, which have a low thermal conductivity, are those, which have a high proportion of small voids containing air or gases. These voids are not big enough to transmit heat by convection or radiation, and therefore reduce the flow of heat. Thermal insulation materials come into the latter category. Thermal insulation materials may be natural substances or man-made.

II.   The Need for Insulation

A thermal insulator is a poor conductor of heat and has a low thermal conductivity. Insulationis used in buildings and in manufacturing processes to prevent heat loss or heat gain. Although its primary purpose is an economic one, it also provides more accurate control of process temperatures and protection of personnel. It prevents condensation on cold surfaces and the resulting corrosion. Such materials are porous, containing large number of dormant air cells. Thermal insulation delivers the following benefits: [1][2]

A.      Energy Conservation

Conserving energy by reducing the rate of heat flow (fig 1) is the primary reason for insulating surfaces. Insulation materials that will perform satisfactorily in the temperature range of -268°C to 1000°C are widely available.

Fig. 1: Thermal insulation retards heat transfer by acting as a barrier in the path of heat flow

B.      Personnel Protection and Comfort

A surface that is too hot poses a danger to people who are working in that area of accidentally touching the hot surface and burning themselves. To prevent this danger and to comply with the OSHA (Occupational Safety and Health Administration) standards, the temperatures of hot surfaces should be reduced to below 60°C (140°F) by insulating them. 

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A Novel High Resolution Adaptive Beam Forming Algorithm for High Convergence

Abstract: This paper introduces a new robust four way LMS and variable step size NLMS beam forming algorithm to reduce interference in a smart antenna system. This algorithm is able to resolve signals arriving from narrowband sources propagating plane waves close to the array end fire. The results of previously used adaptive algorithm have the fixed step size NLMS will result in a trade-off issue between convergence rate and steady-state MSE of NLMS algorithm. This issue is solved by using four way LMS and VSSNLMS which will improve the efficiency of the convergence point. The proposed algorithm implemented reduces the mean square error (MSE) and shows faster convergence rate when compared to the conventional NLMS.

Keywords: Adaptive Antenna, Beamforming, Means Square Error (MSE), Convergence

I.   Introduction

A.      Introduction

In today’s world numbers of mobile users are increasing day by day, hence it is necessary to serve such a huge market of mobile users with high QOS even though the spectrum is limited. This becomes a major challenging problem for the service providers to solve. A major limitation in capacity and performance is co-channel interference caused by the increasing number of users and the multipath fading and delay spread. Research efforts investigating effective technologies to mitigate such effects have been going on and among these methods Adaptive antenna employment is the most promising technology. This project works on Adaptive Antenna which ensures high capacity providing with the same Quality of Service(QOS).In a normal scenario currently the mobile towers employ parabolic dish or a horn antenna but this suffers if the SNR is low the signals have to be repeatedly retransmitted from mobile station to base station. The use of Adaptive Antenna considers an array of antennas in which the antenna will receive the delayed versions of the electromagnetic wave and adds them to achieve high SNR.

B.      Problem Statement

In the earlier antenna radiation was directed based on frequency or time, Therefore spectrum was not utilized efficiently because as the number of users increases the quality of service decreases. Hence, in this work a solution to use the Adaptive antenna frameworks have been proposed and used as an efficient means to meet the quickly expanding the  traffic volume. This issue of Technology has discusses the importance of various advanced antenna schemes for improving the same amount of spectrum and provides service to the large amount of mobile users is deduced. This is done by separating the users with respect to direction.

II.                Adaptive antenna

Adaptive antenna is the one which adapts itself to pick the user signal in any direction without user intervention , basically it undergoes through a two phase process:

-         Direction detection Estimation (DDE) using a suitable algorithm and sensor data.

-         Beam forming which forms a beam in the desired direction and nulls in the interference direction.

Direction Detection Estimation (DDE) methods are used to detect the incoming wave and the other signals which arrive from different parts of the space can be processed to extract different type of data including direction desired incoming signal falling on the antenna array.

Beam forming is a process of forming the Main beam in the desired direction and nulls in the direction of jammers direction. The block diagram is shown in  Figure1 shows an adaptive antenna structure with N antenna elements, DDE blocks, Adaptive signal processor algorithms to make adaptive antenna system smart, where incoming signal is processed by beam forming algorithms the figure also shows main beam formed in the direction of desired signal and nulls in the jammers direction.

Fig. 1: Adaptive Antenna

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New Camera Sensor Eliminates Need for Flash #IJIRST

#IJIRST - Impact factor 1.638

No flash? No problem. A new imaging sensor could soon make it possible for photographers to take clear, sharp photos, even in dim lighting.

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Created by a team of researchers at Nanyang Technological University (NTU) in Singapore, the new sensor is highly sensitive to both visible and infrared light, which means it could be used in everything from the family Nikon to surveillance and satellite cameras.

IJIRST - IMPACT FACTOR 1.638

The sensor, which is 1,000 times more sensitive to light than the imaging sensors of most of today's cameras, gets this high photoresponse from its innovative structure.

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#IJIRST - Impact Factor

International Journal for Innovative Research in Science and Technology (IJIRST) is a one of the popular international multidisciplinary, open access, peer-reviewed, fully refereed journal. It is an international journal that aims to contribute to the constant innovative research and training, so as to promote research in the field of science and technology.

 IMPACT FACTOR – 1.638

360-Degree Infrared Vision : #IJIRST

Thermal Radar

Photograph by Ralph Smith

Michael Dortch was building video surveillance trailers for industrial parks in Colorado when his clients started asking for near-omniscient views of their properties. They wanted to see intruders in the dark from all angles, but such coverage required up to seven thermal infrared cameras and cost more than $100,000. So Dortch and a colleague spent four years developing a cheaper, more capable alternative. Their Thermal Radar system provides 360-degree infrared coverage that can spot people, fires, vehicles, and more.

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The heart of the invention is a single, spinning thermal sensor. Onboard processors constantly stitch images together for a refreshing panoramic video feed, and intelligent software finds threats.

A finished unit will cost about $16,000—many times cheaper than any system that comes close—and should be ready for its debut later this year. The first and biggest market will be corporate security. But the forest service, the Utah Department of Transportation, and even the Pentagon, Dortch says, also have his invention on their radar. how it works

Innovation Redefined... #IJIRST

Evolution of extreme parasites explained by scientists

Extreme adaptations of species often cause such significant changes that their evolutionary history is difficult to reconstruct. Zoologists at the University of Basel in Switzerland have now discovered a new parasite species that represents the missing link between fungi and an extreme group of parasites. Researches are now able to understand for the first time the evolution of these parasites, causing disease in humans and animals. The study has been published in the latest issue of the scientific journal Proceedings of the National Academy of Sciences (PNAS).

Parasites use their hosts to simplify their own lives. In order to do so, they evolved features that are so extreme that it is often impossible to compare them to other species. The evolution of these extreme adaptations is often impossible to reconstruct. The research group lead by Prof. Dieter Ebert from the Department of Environmental Science at the University of Basel has now discovered the missing link that explains how this large group of extreme parasites, the microsporidia, has evolved. The team was supported in their efforts by scientists from Sweden and the U.S.

Innovation Redefined. . . @IJIRST

Between fungi and parasite

The team of zoologists lead by Prof. Dieter Ebert has been studying the evolution of microsporidia for years. When they discovered a new parasite in water fleas a couple of years ago, they classified this undescribed species as a microsporidium, mostly because it possessed the unique harpoon-like infection apparatus (the polar-tube), one of the hallmarks of microsporidia. The analysis of the entire genome had several surprises in store for them: The genome resembles more that of a fungi than a microsporidium and, in addition, also has a mitochondrial genome. The new species, now named Mitosporidium daphniae, thus represents the missing link between fungi and microsporidia.

Source:

The above story is based on materials provided by Universität Basel. Note: Materials may be edited for content and length.

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