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• Studying the thermal and electrical characteristics of individual crystalline silicon cells under different shading levels shows the impact on the module performance. • Advancing the understanding of the impact of partial shading and mismatch on thermal and electrical characteristics of cells, substrings, and modules. • This study improves the interpretation and understanding of thermal images of PV modules operating under varying shading conditions. Variable partial shading was used to analyse the electrical and thermal behaviour of 60 individual cells in an operational crystalline silicon (c-Si) Photovoltaic (PV) module by recording Thermal Infrared (TIR) images concurrently with electrical measurements of individual cells when shading levels between 0 and 100% were applied on one cell. This study investigated the relative changes in each of the individual cells' operational cell voltage and the current of the substring containing the shaded cell. These changes are significant and can give additional insights into the loss of energy production of a module containing a shaded cell. The role of bypass diodes in mitigating these energy losses was also highlighted in this study. The bypass diode gets activated at 40% cell shading level and when the shading level increased from 40- to 100%, the operational voltage and current of the module remain unchanged while that of the shaded cell and substring containing the shaded cell is reduced. The operational temperature of the shaded cell increases to a maximum with an increase in shading level and drops when the substring's bypass diode is activated. As expected, the substring containing the shaded cell tends to operate closer to open-circuit voltage (V OC) as the cells contribute less current than cells in unshaded substrings. The study gives insight into the performance of a c-Si module down to cell level under partial shading on real field conditions and can add value into the operation and TIR imaging of crystalline modules. [ABSTRACT FROM AUTHOR]

The accurate and efficient prediction of the flow and temperature fields on water surface modulated by internal waves induced by underwater vehicles in a density-stratified ocean can serve as the basis for indirect detection. The disturbance of an underwater object on density-stratified water can be considered as the mixing of two incompressible fluids: freshwater and saltwater. Furthermore, the modulation effect of internal waves on the convergence and divergence of flow field and thermal skin layer is captured at the air–water interface. Therefore, in this study, a CFD solver called "interMixing_skin_Foam" based on OpenFOAM is proposed. It can manage three incompressible fluids, two of which disperse, and the interface between the immiscible fluids (air–water) is captured using the VOF technique. In addition, the energy equation is implemented to investigate the thermal signature variations at the air–water interface. Comparison analysis of experimental results and those obtained from the CFD solver "twoLiquidMixing_skin_Foam" developed in a previous study, wherein only two incompressible fluids were considered, is performed for standard cases in literature. Subsequently, the influence of the air–water interface on the flow and temperature fields is studied for a submerged sphere travelling horizontally in linearly and strongly density-stratified water. • The thermal signature variations of internal waves by underwater target at the air–water interface were investigated. • A solver based on OpenFOAM platform for flow and temperature fields of three incompressible fluids was developed. • The viscosity drag effect, surface tension, and movable free surface have significant influence on thermal signatures. • In strongly density-stratified water, the upper fresh-water layer could suppress the thermal signatures. [ABSTRACT FROM AUTHOR]

[Display omitted] • An in-situ monitoring method and similarity analysis algorithm has been developed as a potential tool for part qualification based on thermal signature comparison in additive manufacturing. • The similarity analysis algorithm combines shape and magnitude similarity in a manner unique to additive manufacturing. • Using similarity analysis, variations in thermal signatures associated with change in part geometry have been demonstrated. • Comparison with microstructure characterized using ex-situ microscopy indicated that similarity analysis correlates well with grain size and microstructure variation within a part. • A proof of concept is also presented to demonstrate similarity analysis to identify anomalous regions corresponding to potential defects in the part. Metal additive manufacturing differs from traditional manufacturing processes primarily due to repeated heating and cooling cycles that are inherent to the process. Such cycling leads to different thermal signatures and associated heterogeneities in solidification, solid-state transformation, microstructure, and properties of the printed part. There is, therefore, a need to develop methods to compare thermal signatures in a part with reference to part qualification criteria. In this work, we have developed and demonstrated a similarity analysis procedure to meet this need. Thermal signatures are extracted from in-situ infrared (IR) thermography during a part built using a laser powder bed fusion (l -PBF) machine. Layer-wise variations in thermal signature as a function of part geometry were revealed. Ex-situ microstructure characterization was used to validate the results from similarity analysis. Results and analysis confirmed that our similarity analysis is indeed a useful tool for rapid comparison of thermal signatures, i.e., heterogeneity within the part. Similarity analysis was also useful in identification of anomalous thermal signatures. The analysis method paves the way for deploying in-situ monitoring of AM parts for qualification of AM components. [ABSTRACT FROM AUTHOR]

Summary Submarine groundwater discharge (SGD) to the Bay of Bengal is an important groundwater discharge process to southern Asia as well as to the global oceans. Water-fluxes in these regions are not very well understood. The present study demonstrates the use of sea-bed porewater temperature as a tracer for delineating seasonal SGD from a shallow coastal aquifer to the Bay of Bengal. Porewater temperature mapping along with chemical profile of porewater column were used to delineate groundwater discharge zones for different seasons in a hydrologic year. While, the temperature profiles were used to evaluate total groundwater discharge (both terrestrial and marine), the salinity and total dissolved solids profiles were used to evaluate the component due to terrestrial (freshwater) discharge. Several springs and seeps were mapped to finger-print the freshwater discharge zones and identify the terrestrial sourced-SGD temperature windows. These zones are also identified to be enriched with algal mats, and hence may indicate the pathways of nutrient–solute discharge that enhance the primary productivity in the marine ecosystem. Assuming vertical flow in the seabed, simulated rates of discharged groundwater provided a good match with measured discharge rates. The porewater fluxes were estimated by applying analytical solutions of the heat conduction–advection equations to the observed vertical temperature profiles. High resolution thermal profiles to identify T-SGD signatures and chemical profiles along mapped transects reveal the nuances of 3-D seasonal hydrodynamics of groundwater–seawater interactions. The calculated vertical porewater fluxes through the seabed ranged from negligible to 2.45 × 10 −2 m 3 /m 2 /d 1 within a zone extending from high tide line to 40 m offshore, and represent the vertical porewater velocity and the average vertical porewater velocity is found as 8.2 × 10 −3 m 3 /m 2 /d 1 . Approximations suggest that in present-day condition, total average annual SGD to Bay of Bengal is about 1.16 × 10 7 m 3 /y. Seasonal estimates suggest that the averages SGD during pre-monsoon and post-monsoon seasons are ranges 0.6–0.8 × 10 7 m 3 /y for pre-monsoon and 0.8–1.5 × 10 7 m 3 /y for post-monsoon, respectively. The findings suggest that monsoonal activity result in a significant porewater displacement from tidal flat sediments by increased groundwater discharge. [ABSTRACT FROM AUTHOR]

In Laser Directed Energy Deposition (DED-L) process, based on the particular thermal cycle followed during the laser processing, a wide range of microstructural and dimensional outcomes are envisaged in the end product on account of the interaction of the material or the alloy with the laser. Various parameters can influence the thermal cycle and a direct correlation between the thermal characteristics with the mechanical/metallurgical properties would be helpful to control the process in a better way. Keeping in view of this, the present study is aimed at analyzing thermal signals received from infrared pyrometer and understanding the correlation between thermal signatures, phase prediction data using CALPHAD simulation, microstructure and deposition characteristics. The thermal signatures captured from infrared pyrometer revealed close interrelationship between the input process parameters and the molten pool characteristics, which have a huge influence on the solidification rate vis-à-vis microstructural properties. Total life of melt-pool showed an increase in magnitude from 137 ms to 264 ms with decrease in cooling rates from 3000 °C/s to 1750 °C/s. The grain size increased from 3.48 μm to 7.74 μm with increase in solidification shelf life from 32 ms to 110 ms. The higher solidification shelf life and lower cooling rates also resulted in the larger and the more prominent metal carbide precipitate and intermetallic formations as evident from XRD analysis. Microhardness of the deposits also increased with decrease in solidification shelf life and increase in cooling rates of molten pool. The dimensions of laser deposited tracks were also found to increase with increment in total molten pool lifetime both at increasing laser power and decreasing laser scan peed conditions. • Inconel 625 tracks were deposited at constant power, scan speed and fluence conditions by DED-L. • Shift in solidification shelf life indicated dilution of Fe from SS 304 L substrate. • Increment of solidification shelf life at constant fluence was detected. • Solidification shelf life and cooling rate influenced microstructure and microhardness. • 244 % increase in shelf life led to 122 % increase in grain size at constant scan speed. • Increase in track cross-sectional dimension at constant fluence condition was observed. [ABSTRACT FROM AUTHOR]

In Laser Directed Energy Deposition (DED-L) process, based on the particular thermal cycle followed during the laser processing, a wide range of microstructural and dimensional outcomes are envisaged in the end product on account of the interaction of the material or the alloy with the laser. Various parameters can influence the thermal cycle and a direct correlation between the thermal characteristics with the mechanical/metallurgical properties would be helpful to control the process in a better way. Keeping in view of this, the present study is aimed at analyzing thermal signals received from infrared pyrometer and understanding the correlation between thermal signatures, phase prediction data using CALPHAD simulation, microstructure and deposition characteristics. The thermal signatures captured from infrared pyrometer revealed close interrelationship between the input process parameters and the molten pool characteristics, which have a huge influence on the solidification rate vis-à-vis microstructural properties. Total life of melt-pool showed an increase in magnitude from 137 ms to 264 ms with decrease in cooling rates from 3000 °C/s to 1750 °C/s. The grain size increased from 3.48 μm to 7.74 μm with increase in solidification shelf life from 32 ms to 110 ms. The higher solidification shelf life and lower cooling rates also resulted in the larger and the more prominent metal carbide precipitate and intermetallic formations as evident from XRD analysis. Microhardness of the deposits also increased with decrease in solidification shelf life and increase in cooling rates of molten pool. The dimensions of laser deposited tracks were also found to increase with increment in total molten pool lifetime both at increasing laser power and decreasing laser scan peed conditions. • Inconel 625 tracks were deposited at constant power, scan speed and fluence conditions by DED-L. • Shift in solidification shelf life indicated dilution of Fe from SS 304 L substrate. • Increment of solidification shelf life at constant fluence was detected. • Solidification shelf life and cooling rate influenced microstructure and microhardness. • 244 % increase in shelf life led to 122 % increase in grain size at constant scan speed. • Increase in track cross-sectional dimension at constant fluence condition was observed. [ABSTRACT FROM AUTHOR]

A model of thermal phenomenon in soil developed to determine its thermal signatures in case of buried land mines in presented in the paper. Thermal signature values of a mine buried in two types of soil having different properties were compared using mathematical–statistical modelling. Results generated by modelling have been verified by laboratory experiment. [Copyright &y& Elsevier]

A submerged body moving in density-stratified water, such as in oceans, disturbs the surrounding water layers. Furthermore, the internal waves generate and modulate the flow field on the water surface. Thereafter, the thin water surface layer and underlying water, which differ in temperatures because of factors such as solar radiation and water vapor exchange, mix. Consequently, thermal signatures could be generated on the water surface and detected by high-resolution infrared equipment; hence, the presence of a submerged moving body could also be deduced. To thoroughly examine this phenomenon, a submerged sphere moving horizontally in linearly density-stratified water with a "hot skin" layer on its surface was numerically studied in this work. A suitable solver, i.e., "twoLiquidMixing_skin_Foam", based on the well-known open-source computational fluid dynamics code, "Open-Source Field Operation and Manipulation", was developed for the aforementioned problem. The internal waves excited by the sphere were validated by experimental results to illustrate the accuracy of the developed solver. Then, the impact of lee waves on the water surface thermal signatures was investigated in detail for the towed submerged sphere moving at various depths in fluid with different internal Froude numbers. • The surface thermal signatures of internal waves excited by underwater target are studied. • A suitable solver "twoLiquidMixing_skin_Foam", based on OpenFOAM, was developed for CFD simulation. • The thermal signatures could be interpreted by wave pattern and far wake pattern regions with a low Froude number. [ABSTRACT FROM AUTHOR]

The shear-phase compound TiNb 2 O 7 has recently emerged as a safe and high-volumetric density replacement for graphite anodes in lithium ion batteries. An appealing feature of TiNb 2 O 7 is that it retains capacity even at high cycling rates. Here, we demonstrate that phase pure and crystalline TiNb 2 O 7 can be rapidly prepared using a high-temperature microwave synthesis method. Studies of the charging and discharging of this material, including through operando calorimetry, permit key thermodynamic parameters to be revealed. The nature of heat generation is dominated by Joule heating, which sensitively changes as the conductivity of the electrode increases with increasing lithiation. The enthalpy of mixing, obtained from operando calorimetry, is found to be small across the different degrees of lithiation, pointing to the high rate of lithium ion diffusion at the origin of rapid rate performance. • Crystalline TiNb 2 O 7 particles are synthesized in 7–8 min using microwave heating. • Entropy measurements suggest intralayer lithium ordering at low lithium composition. • Energy balance shows that electrical energy losses are dissipated in the form of heat. • Joule heating captures changes in TiNb 2 O 7 electrical conductivity during cycling. • Small enthalpy of mixing at high C-rates is a sign of a high cycling rate material. [ABSTRACT FROM AUTHOR]