Thermal energy reservoir capacities for solar absorption cooling systemsCapacité des accumulateurs d'énergie thermique pour les systèmes frigorifiques à absorption solaires

It is essential to incorporate both hot and cold energy storage for a solar absorption cooling system in order to maximize the saving of conventional electrical power. The paper correlates the thermal energy storage requirements with the daily cooling demand pattern of a building. The other parameters which affect the choice of the two storage volumes are the effective sunshine hours, the chiller cooling capacity, its daily operation period and the two storage temperature differentials. The results have been obtained in a generalized manner and applied to an actual building in Kuwait.     

Novel LOX Variants in Five Families with Aortic/Arterial Aneurysm and Dissection with Variable Connective Tissue Findings

Thoracic aortic aneurysm and dissection (TAAD) is a major cause of cardiovascular morbidity and mortality. Loss-of-function variants in LOX, encoding the extracellular matrix crosslinking enzyme lysyl oxidase, have been reported to cause familial TAAD. Using a next-generation TAAD gene panel, we identified five additional probands carrying LOX variants, including two missense variants affecting highly conserved amino acids in the LOX catalytic domain and three truncating variants. Connective tissue manifestations are apparent in a substantial fraction of the variant carriers. Some LOX variant carriers presented with TAAD early in life, while others had normal aortic diameters at an advanced age. Finally, we identified the first patient with spontaneous coronary artery dissection carrying a LOX variant. In conclusion, our data demonstrate that loss-of-function LOX variants cause a spectrum of aortic and arterial aneurysmal disease, often combined with connective tissue findings.     

Influence of target grit count and sintering temperature on pulsed laser deposition of SiC thin films

A pulsed laser deposition (PLD) technique for depositing SiC on Si(100) substrates using Nd³⁺:YAG laser at 355 nm is studied. The influence of substrate temperature, ambient pressure, and SiC powder grit size on both structure and morphology of SiC thin film is investigated. Further, the influence of the target preparation on the reduction of droplet formation during Nd³⁺:YAG laser-assisted pulsed laser deposition of SiC thin films is investigated. Experimental studies show that multicrystalline SiC film can be obtained with temperature ranging from 600 to 700 °C and at an ambient pressure of about 5.5 × 10^?3 Pa. Further, droplet formation on the deposited film was reduced significantly by selecting the grit count of SiC powder 500 and the pressure of 2 × 10^?2 Pa. SiC target sintered at 1,600 °C showed a reduced wear during the laser ablation. The X-ray diffraction (XRD) and the Raman spectroscopy studies on deposited films clearly show the multicrystalline (combined 3C-SiC and 4H-SiC) nature of SiC films. I-V characteristics of deposited SiC film on n-type c-Si substrate also indicated that SiC thin film possesses P-type semiconductor properties.     

One-pot facile synthesis and electrochemical evaluation of selenium enriched cobalt selenide nanotube for supercapacitor application

The present study emulates a one-pot facile synthesis of selenium-enriched CoSe nanotube using a chemical bath deposition (CBD) procedure. Schematic incorporation of 3D Ni foam current collectors as substrates for the growth of CoSe–Se nanotubes helped us achieve a binder-less thin film coating. The controlled synthesis of CoSe–Se nanotube was carried out by optimizing the temperature and time of the deposition. CoSe–Se nanotubes were grown on a porous Ni foam substrate using lithium chloride as a shape directing agent. The study found that the one dimensional structure of the nanotubes with porous nature results in an uninterrupted network of electroactive sites. Due to the superior conductivity, the as-fabricated material exhibited excellent rate capability and a higher degree of electrolyte ion diffusion across the CoSe–Se crystal structure. The CoSe–Se@Ni foam electrodes exhibited a specific capacitance of 1750.81 F g^?1 at 1 A g^?1. The electrode exhibited excellent cycling stability and showed a capacitance retention of 95% after 4000 charge-discharge cycles. Finally, an asymmetric supercapacitor (ASC) device was fabricated with the as-synthesized CoSe–Se@Ni foam electrode as the cathode, activated carbon@Ni foam electrode as the anode, and a thin filter paper separator soaked in 1 M aqueous KOH electrolyte solution. The ASC device showed a specific capacitance value of 106.73 F g^?1 at 0.5 A g^?1, and achieved an energy density of 37.94 Wh kg^?1 at a power density of 475.30 W kg^?1. The ASC device was utilized in an extended potential window of 1.6 V. The fabricated device displayed exceptional cycling stability with a capacitance retention of 93% after 5000 charge-discharge cycles.     

Impact of shape (nanofiller vs. nanorod) of TiO2 nanoparticle on free-standing solid polymeric separator for energy storage/conversion devices

We report the investigation on examining the impact of nanofiller (NF)- versus nanorod (NR)-shaped titanium oxide (TiO₂) nanoparticle on the structural, electrochemical, transport, thermal, and dielectric properties of the solid polymer electrolyte (SPE). Thin SPE films comprising of poly(ethylene oxide), sodium hexafluorophosphate, and dispersed with TiO₂ NF, TiO₂ NR (synthesized by hydrothermal route) has been prepared via solution cast technique. The shape of nanoparticle influences the morphological and structural properties as observed in field emission scanning electron microscope and X-ray diffraction analysis. The highest ionic conductivity was exhibited by the NR dispersed system and is higher than NF dispersed system for all recorded concentration consistently. It is attributed to the formation of the long-range conductive path with NR when compared with NF. In addition, the electrochemical stability window is much higher (~5 V) than the NF-doped system. Furthermore, the dielectric properties of SPE were investigated and fitted in the complete frequency window (1 Hz–1 MHz; T = 40–100 °C @ 10 °C). It is observed that the NR dispersed system shows higher dielectric strength and low relaxation time with respect to NF dispersed system. The results suggest that the NR dispersed SPE possess enhanced properties and is more appropriate for an application in high energy density solid-state Na ion batteries. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47361.     

Low percolation threshold and high electrical conductivity in melt‐blended polycarbonate/multiwall carbon nanotube nanocomposites in the presence of poly(ε‐caprolactone)

This study focuses on the electrical properties of polycarbonate (PC)/poly(ε‐caprolactone) (PCL)‐multiwall carbon nanotube (MWCNT) nanocomposites. MWCNTs were incorporated into thermoplastic PC matrix by simple melt blending using biodegradable PCL based concentrates with MWCNT loadings (3.5 wt%). Because of the lower interfacial energy between MWCNT and PCL, the nanotubes remain in their excellent dispersion state into matrix polymer. Thus, electrical percolation in PC/PCL‐MWCNT nanocomposites was obtained at lower MWCNT loading rather than direct incorporation of MWCNT into PC matrix. AC and DC electrical conductivity of miscible PC/PCL‐MWCNT nanocomposites were studied in a broad frequency range, 10¹?10⁶ Hz and resulted in low percolation threshold (p_c) of 0.14 wt%, and the critical exponent (t) of 2.09 from the scaling law equation. The plot of logσ_DC versus p^?1/3 showed linear variation and indicated the existence of tunneling conduction among MWCNTs. At low MWCNT loading, the influence of large polymeric gaps between conducting clusters is the reason for the frequency dependent electrical conductivity. Transmission electron microscopy and field emission scanning electron microscopy showed that MWCNTs were homogeneously dispersed and developed a continuous interconnected network path throughout the matrix phase and miscibility behavior of the polymer blend. POLYM. ENG. SCI., 54:646–659, 2014. © 2013 Society of Plastics Engineers     

Lattice Boltzmann modelling of unsteady-state 2D concentration profiles in adsorption bed

This study describes a lattice Boltzmann model (LBM) developed to simulate two-dimensional (2D) unsteady-state concentration profiles, including breakthrough curves, in a tubular column packed with adsorbents. The model using d3q19 (three dimensions and 19 speeds) lattice solves the 3D time-dependent convection-diffusion-adsorption equation for an ideal binary gaseous mixture assuming different velocity profiles in the column, including radially flat (plug flow) and non-uniform across the column's cross-section. The simulation results show significant concentration gradient across the cross-section depending upon the d/d_p ratio. The model results corroborate the experimental measurements made in the adsorption bed that the concentration due to breakthrough may be larger near the wall than at the core of the column due to the relatively larger local velocity in the vicinity of the wall. The LBM results have significance from the perspective of the physical understanding of the concentration profiles prevalent in the adsorption bed as well as effective design of a large-scale column. The model results are validated with the analytical solution to 1D axial dispersion problem, and to a few simple flow problems, such as Poiseuille and Couette flows.     

Passing the Baton: Helping Your Successor to Succeed

When most CIOs transition from one information technology group to that of another company, they seldom think about what happens to their old group once they leave. Instead, the outgoing CIO begins focusing on the challenges of the new situation. A true act of leadership, however, is to consider how to help one's replacement to hit the ground running.