scholarly journals Thermodynamic and Energy Efficiency Analysis of a Domestic Refrigerator Using Al2O3 Nano-Refrigerant

2021 ◽  
Vol 13 (10) ◽  
pp. 5659
Author(s):  
Farhood Sarrafzadeh Javadi ◽  
Rahman Saidur
Keyword(s):  
Temperature Gradient ◽  
Technological Changes ◽  
Nanoparticle Concentration ◽  
Evaporator Temperature ◽  
Domestic Refrigerator ◽  
The Past ◽  
Nano Lubricant ◽  
The Stability ◽  
Energy Efficiency Analysis ◽  
Al2o3 Nanofluid

Refrigeration systems have experienced massive technological changes in the past 50 years. Nanotechnology can lead to a promising technological leap in the refrigeration industry. Nano-refrigerant still remains unknown because of the complexity of the phase change process of the mixture including refrigerant, lubricant, and nanoparticle. In this study, the stability of Al2O3 nanofluid and the performance of a nano-refrigerant-based domestic refrigerator have been experimentally investigated, with the focus on the thermodynamic and energy approaches. It was found that by increasing the nanoparticle concentration, the stability of nano-lubricant was decreased and evaporator temperature gradient was increased. The average of the temperature gradient increment in the evaporator was 20.2% in case of using 0.1%-Al2O3. The results showed that the energy consumption of the refrigerator reduced around 2.69% when 0.1%-Al2O3 nanoparticle was added to the system.

Impact of Area Contact Between Sensor Bulb and Evaporator Return Line on Modular Refrigeration Unit: Computational and Experimental

2005 ◽  
Vol 127 (1) ◽  
pp. 95-100 ◽  
Author(s):  
Saket Karajgikar ◽  
Nikhil Lakhkar ◽  
Dereje Agonafer ◽  
Roger Schmidt
Keyword(s):  
Mechanical Analysis ◽  
Evaporator Temperature ◽  
Thermally Induced ◽  
The Past ◽  
Refrigeration Unit ◽  
Expansion Valve ◽  
Flow Through ◽  
The Stability ◽  
Experimental Bench ◽  
Server System

In the past, virtually all commercial computers were designed to operate at temperatures above the ambient and were primarily air-cooled. However, researchers have always known the advantages of operating electronics at low temperatures. This facilitates faster switching time of semiconductor devices, increased circuit speeds due to lower electrical resistance of interconnecting materials, and reduction in thermally induced failures of devices and components. Depending on the doping characteristics of the chip, performance improvement ranges from 1% to 3% for every 10°C lower transistor temperature can be realized. The IBM S/390 high-end server system is the first IBM design which uses a conventional refrigeration system to maintain the chip temperatures below that of comparable air-cooled systems, but well above cryogenic temperature. In previous work, the focus was to study the effect of variation of evaporator outlet superheat on the flow through thermostatic expansion valve at varying evaporator temperature. The effect of change in bulb location and effect of bulb time constant on the hunting at the evaporator has been reported. The effect of area contact on the stability of the system is been predicted theoretically. Mechanical analysis is performed in order to check the stresses induced. The evaporator return line and the sensor bulb are simply attached. The effect of area contact is further studied experimentally on an experimental bench.

Stability and Folding of the Unusually Stable Hemoglobin from Synechocystis is Subtly Optimized and Dependent on the Key Heme Pocket Residues.

2020 ◽  
Vol 27 ◽  
Author(s):  
Sheetal Uppal ◽  
Mohd. Asim Khan ◽  
Suman Kundu
Keyword(s):  
Molten Globule ◽  
Life Forms ◽  
Model System ◽  
Heme Pocket ◽  
The Past ◽  
Specific Manner ◽  
Delivery Vehicles ◽  
The Stability ◽  
Key Residues ◽  
Synechocystis Sp

Aims: The aim of our study is to understand the biophysical traits that govern the stability and folding of Synechocystis hemoglobin, a unique cyanobacterial globin that displays unusual traits not observed in any of the other globins discovered so far. Background: For the past few decades, classical hemoglobins such as vertebrate hemoglobin and myoglobin have been extensively studied to unravel the stability and folding mechanisms of hemoglobins. However, the expanding wealth of hemoglobins identified in all life forms with novel properties, like heme coordination chemistry and globin fold, have added complexity and challenges to the understanding of hemoglobin stability, which has not been adequately addressed. Here, we explored the unique truncated and hexacoordinate hemoglobin from the freshwater cyanobacterium Synechocystis sp. PCC 6803 known as “Synechocystis hemoglobin (SynHb)”. The “three histidines” linkages to heme are novel to this cyanobacterial hemoglobin. Objective: Mutational studies were employed to decipher the residues within the heme pocket that dictate the stability and folding of SynHb. Methods: Site-directed mutants of SynHb were generated and analyzed using a repertoire of spectroscopic and calorimetric tools. Result: The results revealed that the heme was stably associated to the protein under all denaturing conditions with His117 playing the anchoring role. The studies also highlighted the possibility of existence of a “molten globule” like intermediate at acidic pH in this exceptionally thermostable globin. His117 and other key residues in the heme pocket play an indispensable role in imparting significant polypeptide stability. Conclusion: Synechocystis hemoglobin presents an important model system for investigations of protein folding and stability in general. The heme pocket residues influenced the folding and stability of SynHb in a very subtle and specific manner and may have been optimized to make this Hb the most stable known as of date. Other: The knowledge gained hereby about the influence of heme pocket amino acid side chains on stability and expression is currently being utilized to improve the stability of recombinant human Hbs for efficient use as oxygen delivery vehicles.

scholarly journals Copper Phyllosilicates-Derived Catalysts in the Production of Alcohols from Hydrogenation of Carboxylates, Carboxylic Acids, Carbonates, Formyls, and CO2: A Review

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 255
Author(s):  
Dien-Thien To ◽  
Yu-Chuan Lin
Keyword(s):  
Carboxylic Acids ◽  
Catalytic Performance ◽  
Spatial Effect ◽  
Synthesis Methods ◽  
The Past ◽  
Surface Areas ◽  
Preparation Conditions ◽  
Remedial Actions ◽  
The Stability ◽  
Size Interaction

Copper phyllosilicates-derived catalysts (CuPS-cats) have been intensively explored in the past two decades due to their promising activity in carbonyls hydrogenation. However, CuPS-cats have not been completely reviewed. This paper focuses on the aspects concerning CuPS-cats from synthesis methods, effects of preparation conditions, and dopant to catalytic applications of CuPS-cats. The applications of CuPS-cats include the hydrogenation of carboxylates, carboxylic acids, carbonates, formyls, and CO2 to their respective alcohols. Besides, important factors such as the Cu dispersion, Cu+ and Cu0 surface areas, particles size, interaction between Cu and supports and dopants, morphologies, and spatial effect on catalytic performance of CuPS-cats are discussed. The deactivation and remedial actions to improve the stability of CuPS-cats are summarized. It ends up with the challenges and prospective by using this type of catalyst.

scholarly journals Water confined in solutions of biological relevance

2020 ◽  
Vol 92 (10) ◽  
pp. 1563-1574
Author(s):  
Marie-Claire Bellissent-Funel
Keyword(s):  
Aqueous Solutions ◽  
Bulk Water ◽  
Biological Macromolecules ◽  
Organic Solutes ◽  
Confined Water ◽  
The Past ◽  
Structure And Dynamics ◽  
Biological Relevance ◽  
The Stability

AbstractIn many relevant situations, water is not in its bulk form but instead attached to some substrates or filling some cavities. We shall call water in the latter environment confined water as opposed to bulk water. It is known that the confined water is essential for the stability and the function of biological macromolecules. In this paper, we provide a review of the experimental and computational advances over the past decades concerning the understanding of the structure and dynamics of water confined in aqueous solutions of biological relevance. Examples involving water in solution of organic solutes (cryoprotectants such as dimethylsulfoxide (DMSO), sugars such as trehalose) are provided.

Future Directions in Surface Electromyography

Biofeedback ◽  
2010 ◽  
Vol 38 (2) ◽  
pp. 78-82 ◽  
Author(s):  
John G. Arena
Keyword(s):  
Surface Electromyography ◽  
Ambulatory Monitoring ◽  
Future Directions ◽  
The Past ◽  
Psychophysiological Assessment ◽  
The Future ◽  
The Stability

Abstract The use of surface electromyography (SEMG) has increased exponentially in the past four decades. SEMG is one of the most widespread measures employed today in psychophysiological assessment and one of three primary biofeedback modalities. This article briefly outlines three areas that the author believes are important for SEMG to address if it is to continue to flourish in the future: applications in telehealth, the use of telemetry and ambulatory monitoring, and studies on the stability or reliability of surface electromyography.

scholarly journals Spatial aspect of modern warfare: from traditional warfare to cyberwar

2021 ◽  
pp. 136-149
Author(s):  
Natalia Aleksandrovna Balakleets
Keyword(s):  
Military Leaders ◽  
The Past ◽  
The Earth ◽  
Total Destruction ◽  
Spatial Aspect ◽  
Pessimistic Scenario ◽  
The Stability ◽  
Military Activity ◽  
Modern Warfare ◽  
The Military

This author substantiates the thesis on the importance of spatial factors for conducting warfare. The article traces the evolution of warfare associated with the involvement of new territories and new types of spaces in the orbit of military activity. If the warfare of the past demonstrated a direct dependence on the geographical territory and the related “tensions” (C. von Clausewitz), the modern warfare are emancipated from the geographical shell of the Earth. The article explicates the factors that justify the need for arranging the new warfare spaces. Special attention is given to cyberspace, its structure, and conflicts unfolding therein. The scientific novelty of consists in the interpretation of cyberspace as an expected result of the spatial evolution of warfare. The conclusion is drawn that the emergence of cyberspace contributes to solution of the problem of information vagueness and creation of the stability zones for the military leaders, but at the same is a source of problems not less dangerous for the humanity. The cyberwar winner faces a tempting challenge of establishing global control over the territory of the plane using cyberweapon, or in most pessimistic scenario, its total destruction.

Photo-Journalism: An Annotated Bibliography

1947 ◽  
Vol 24 (3) ◽  
pp. 243-249
Author(s):  
Roland E. Wolseley
Keyword(s):  
Assistant Professor ◽  
Annotated Bibliography ◽  
State University ◽  
Technological Changes ◽  
Graphic Arts ◽  
Kent State University ◽  
The Past ◽  
The Subject ◽  
Syracuse University ◽  
Radio News

The brevity of this bibliography can be blamed, not on its compiler's unwillingness to search the photography and journalism publications or the book shelves of numerous libraries and supply shops, but upon the editor's explicit instructions and the scarcity of material. Professor Arpan's specific orders were: “The bibliography should contain references to photo-journalism only and should skip photography in general.” Precisely that was done, although “photo-journalism” was interpreted broadly. It meant that a few general books of special help should be included; it meant, also, a little attention to television and the news reel. Having prepared a bibliography in the field of general journalism, the compiler knew that little had been written on photo-journalism. He was not prepared, however, for the realization that most writing on the subject is either badly out-of-date or superficial. Articles in such journals as Camera, American Photographer, Editor and Publisher, and Popular Photography usually are topical and timely but therefore highly perishable. So many technological changes have occurred in the past few years that whole books have become mere curiosities. Popular taste has affected photo-journalism also, stimulated by the growth of the picture magazine. Photo-journalism, like newspaper circulation, radio news writing, and country journalism, is wide open for up-to-date and thorough treatment by textbook authors. At this writing there is no single book, dated later than 1939, which is intended as a basic text in a photo-journalism course or at least suitable for such use. The compiler wishes to thank James Fosdick, assistant professor of photography, Kent State University, and C. Wesley Brewster, instructor in graphic arts, Syracuse University, for their suggestions.

A Variable Viscosity Approach for the Analysis of Steady State and Dynamic Characteristics of Two-Lobe Journal Bearing With TiO2 Based Nanolubricant

2017 ◽  
Author(s):  
Ashutosh Kumar ◽  
Sashindra Kumar Kakoty
Keyword(s):  
Steady State ◽  
Dynamic Characteristics ◽  
Journal Bearing ◽  
Volume Fraction ◽  
Variable Viscosity ◽  
Flow Coefficient ◽  
Viscosity Model ◽  
Nano Lubricant ◽  
The Stability ◽  
Stiffness And Damping

Steady-state and dynamic characteristics of two-lobe journal bearing, operating on TiO2 based Nano-lubricant has been obtained. The effective viscosity is obtained by using Krieger-Dougherty viscosity model for a given volume fraction of nanoparticle in the base fluid. Various bearing performance characteristics are then obtained by solving modified Reynolds equation for variable viscosity model and couple stress model. The stiffness and damping coefficients are also determined for various values of the volume fraction of the nanoparticle in the nanofluid. Results reveal that load carrying capacity and flow coefficient increase whereas friction variable decreases without affecting the stability condition of two-lobe journal bearing operating on TiO2 based nanolubricant. On the other hand attitude angle and dynamic coefficients remains constant for all the values of volume fraction of nanoparticle.

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