The use of a latent heat storage system using phase change materials (PCMs) is an effective way of storing thermal energy and has the advantages of high-energy storage density and the isothermal nature of the storage process. PCMs have been widely used in latent heat thermal-storage systems for heat pumps, solar engineering, and spacecraft thermal control applications. The uses of PCMs for heating and cooling applications for buildings have been investigated within the past decade. There are large numbers of PCMs that melt and solidify at a wide range of temperatures, making them attractive in a number of applications. This paper also summarizes the investigation and analysis of the available thermal energy storage systems incorporating PCMs for use in different applications.

Review on thermal energy storage with phase change materials and applications

A comprehensive review of various possible methods for heating and cooling in buildings are discussed in this paper. The thermal performance of various types of systems like PCM trombe wall, PCM wallboards, PCM shutters, PCM building blocks, air-based heating systems, floor heating, ceiling boards, etc., is presented in this paper. All systems have good potential for heating and cooling in building through phase change materials and also very beneficial to reduce the energy demand of the buildings.

http://amet-me.mnsu.edu/UserFilesShared/SolarWall/Solar%20Passive%20%28Trombe%29%20Wall%20Documents/Technical%20Publications/PCM%20thermal%20storage%20in%20buildings%20-%20A%20state%20of%20art.pdf

PCM thermal storage in buildings: A state of art

The present paper is the first comprehensive review of the integration of phase change materials in building walls. Many considerations are discussed in this paper including physical considerations about building envelope and phase change material, phase change material integration and thermophysical property measurements and various experimental and numerical studies concerning the integration. Even if the integrated phase change material have a good potential for reducing energy demand, further investigations are needed to really assess their use.

/pdf/a-review-on-phase-change-materials-integrated-in-building-2uggcbgrkr.pdf

A review on phase change materials integrated in building walls

Review of passive PCM latent heat thermal energy storage systems towards buildings’ energy efficiency

The sea-ice cover around Antarctica has experienced a slight expansion in area over the past decades1, 2. This small overall increase is the sum of much larger opposing trends in different sectors that have been proposed to result from changes in atmospheric temperature or wind stress3, 4, 5, precipitation6, 7, ocean temperature8, and atmosphere or ocean feedbacks9, 10. However, climate models have failed to reproduce the overall increase in sea ice11. Here we present a data set of satellite-tracked sea-ice motion for the period of 1992–2010 that reveals large and statistically significant trends in Antarctic ice drift, which, in most sectors, can be linked to local winds. We quantify dynamic and thermodynamic processes in the internal ice pack and show that wind-driven changes in ice advection are the dominant driver of ice-concentration trends around much of West Antarctica, whereas wind-driven thermodynamic changes dominate elsewhere. The ice-drift trends also imply large changes in the surface stress that drives the Antarctic ocean gyres, and in the fluxes of heat and salt responsible for the production of Antarctic bottom and intermediate waters.

Wind-driven trends in Antarctic sea ice drift

We report the synthesis of nanostructured austenitic AISI 304L stainless steel (SS) through cryorolling (CR) and reversion annealing in the temperature range of 700–800 °C. Severe CR at sub-zero temperature promotes twinning in γ-austenite, which transform into α׳-martensite with lath thickness of 50–100 nm. Whereas, 50–300 nm size γ-grains recrystallize in nano-twinned α׳ through reversion annealing as confirmed by transmission electron microscopy (TEM) and electron back scattered diffraction (EBSD) imaging. The evolution of highly processable bulk nano-austenitic SS with bimodal grain size distribution on achieving high strength (~1295 MPa), large tensile ductility (~0.47), and true necking strain of 0.59, have been discussed.

Effect of cryorolling on the microstructure and tensile properties of bulk nano-austenitic stainless steel

Understanding the seasonal cycle of Antarctic sea ice extent in the context of longer‐term variability

Tribological performance of sulfur, phosphorous and metal-free Schiff bases of 4-aminoantipyrine with benzaldehyde (AAPB), salicylaldehyde (AAPS), p-chlorobenzaldehyde (AAPC) and p-methoxybenzaldehyde (AAPM) and their synergistic formulations with borate ester (BE) in paraffin oil has been evaluated using a four-ball tester at optimized concentrations of Schiff bases (1% w/v) and their synergistic formulations with BE (0.5% w/v for each) by varying loads for 30 min duration and varying test durations at 392 N load. Synergistic formulations effectively enhance antiwear properties of oil and possess high load carrying capacity in comparison to the conventional zinc dibutyldithiophosphate (ZDDP)/BE/Schiff bases alone. The best efficiency is shown by AAPM, followed by AAPC, AAPS and then AAPB. The same order is observed in their corresponding synergistic formulations. AFM and SEM micrographs of the wear scar lubricated with synergistic formulations show a drastic decrease in surface roughness in comparison to borate ester/ZDDP alone. EDX analysis of the worn surface in the presence of AAPM + BE exhibits nitrogen, boron and oxygen indicating adsorption of the additive on the surface. XPS of the tribofilm shows B2O3, BN, Fe2O3, Fe3O4 and adsorbed carbon in the form of –C–C– and –C(O)O– moieties. Quantum chemical calculations (DFT) for interactions of Schiff bases with surfaces show good agreement with experimental results.

Tribological studies of some SAPS-free Schiff bases derived from 4-aminoantipyrine and aromatic aldehydes and their synergistic interaction with borate ester

The paper employs Artificial Neural Network (ANN) to forecast foreign exchange rate in India during 1992-2009. We used two types of data set (daily and monthly) for US dollar, British pound, euro and Japanese yen. The performance of forecasting is quantified by using various loss functions namely root mean square error (RMSE), mean absolute error (MAE), mean absolute deviation (MAD) and mean absolute percentage error (MAPE). Empirical results confirm that ANN is an effective tool to forecast the exchange rate. The technique gives the evidence that there is possibility of extracting information hidden in the foreign exchange rate and predicting it into the future. The evaluation of the proposed model is based on the estimation of the average behaviour of the above loss functions.Keywords- Exchange Rate;  Neural Network

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Forecasting Exchange Rate in India: An Application of Artificial Neural Network Model

Stearic acid modified ceramic nanoparticles SCCZTO-6 h, SCCZTO-8 h and SCCZTO-12 h of average sizes 60, 80 and 90 nm were prepared from CCZTO-6 h, CCZTO-8 h and CCZTO-12 h respectively (where CCZTO represents CaCu2.9Zn0.1Ti4O12; 6 h, 8 h and 12 h are the sintering times). The SCCZTO nanoparticles have been characterized by Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). Tribological behavior of these nanoparticles in liquid paraffin oil has been evaluated using a four-ball lubricant tester and compared with conventional high SAPS containing zinc dialkyldithiophosphates (ZDDP). All antiwear tests have been performed using an optimized concentration of the SCCZTO nanoparticles (1% w/v) by varying the load for a 30 min test duration and by varying the test durations at 392 N load. Various tribological parameters such as mean wear scar diameter (MWD), friction coefficient (μ), mean wear volume (MWV), running-in, steady-state and overall wear rates show that all the SCCZTO nanoparticles act as efficient antiwear additives and possess a high load carrying capacity. The best tribological behavior is shown by SCCZTO-6 h, followed by SCCZTO-8 h and then SCCZTO-12 h. The surface morphology and roughness of the wear scar have been studied by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) respectively. AFM and SEM micrographs of the wear scar in the presence of SCCZTO-6 h and SCCZTO-8 h at 392 N applied load for a 90 min test duration show a drastic decrease in surface roughness. Energy-Dispersive X-ray (EDX) analysis of the worn surface under similar experimental conditions in the presence of SCCZTO-6 h nanoparticles exhibits the presence of calcium, copper, zinc, titanium and oxygen on the worn steel surface indicating tribosinterization and/or adsorption of the additive on the rubbing surface resulting in the formation of a strong tribofilm. X-ray Photoelectron Spectroscopy (XPS) of the tribofilm shows the presence of CaO, CuO, Cu2O, TiO2, Fe2O3 and adsorbed carbon in the form of –C–C– and –C(O)O– moieties.

Rajesh Kumar

Papers

Effect of cryorolling on the microstructure and tensile properties of bulk nano-austenitic stainless steel

Understanding the seasonal cycle of Antarctic sea ice extent in the context of longer‐term variability

Tribological studies of some SAPS-free Schiff bases derived from 4-aminoantipyrine and aromatic aldehydes and their synergistic interaction with borate ester

Forecasting Exchange Rate in India: An Application of Artificial Neural Network Model

Tribological studies of stearic acid-modified CaCu2.9Zn0.1Ti4O12nanoparticles as effective zero SAPS antiwear lubricant additives in paraffin oil