Effects of external reflector and glass cover cooling on thermo-enviro-economic performance of a stepped solar still

In the current research work, performance enhancement of stepped solar still (SSS) having an external reflector (ER) and glass cover cooling (GCC) arrangements is presented. The individual and combined effects of ER and GCC on the performance of SSS have been evaluated and compared with simple SSS. The GCC reduces the glazing temperature significantly and results in increased distillate. The ER reflected the solar radiation inside the basin that increases the water temperature, consequently increasing distillate. The SSS having ER and GCC (SSS-ER-GCC) gave a maximum distillate of 4.340 kg/m² which was observed, respectively, 12.43%, 3.21%, and 1.36% higher than that of simple SSS, SSS with ER (SSS-ER) and SSS with GCC (SSS-GCC). The average energy efficiency of SSS-ER-GCC was evaluated as 40.78%, which was found to be 14.36%, 7.84%, and 10.64%, respectively, higher than that of simple SSS, SSS-ER, and SSS-GCC. The carbon credits earned and CO₂ mitigation were found the maximum for SSS-ER-GCC having values $65.96 and 4.40 tons, respectively. The economic payback period was found the minimum (490 days) for SSS-ER-GCC.     

0.9-V DSP blocks: a 15-ns 4-k SRAM and a 45-ns 16-bmultiply/accumulator

4-k SRAM and 16-b multiply/accumulate DSP blocks have been designed and fabricated in complementary heterostructure GaAs. Both circuits operate from 1.5 V to below 0.9 V. The SRAM uses 28,272 transistors in an area of 2.44 mm². Cell size is 278 μm ² at 1.0-μm gate length. Measured results show an access delay of 5.3 ns at 1.5 V and 15.0 ns at 0.9 V. At 0.9 V, the power dissipated is 0.36 mW. The CGaAs multiplier uses a 16-b modified Booth architecture with a 3-way 40-b accumulator. The multiplier uses 11,200 transistors in an area of 1.23 mm². Measured delay is 19.0 ns at 1.5 V and 44.7 ns at 0.9 V. At 0.9 V, current is less than 0.4 mA     

Personal and social proximity empowering collaborations: the glue of knowledge networks

The proximity framework serves to analyse and understand how collaborations form and develop over time, and how these affect innovation and learning. The framework has inspired and informed empirical studies in several contexts, contributing to our understanding of the dynamics of dyadic collaborations, industrial clusters and districts, and regional innovation systems, to name but a few. Recent conceptual and empirical advances have called attention to the role of personal proximity and social proximity in such collaborations. In addition to other forms of proximity, these two dimensions could make up the glue that holds knowledge networks together. In the introduction to this special issue, we elaborate upon this proposition, setting out a point-of-departure for the three empirical studies collected in this issue. We summarize the findings of these papers, and develop a research agenda from those findings that may guide proximity researchers to novel research problems and useful research designs.     

Gamma dosimetry using red 4034 Harwell dosimeters in mixed fission neutrons and gamma environments

The radiation tolerance testing of materials or opto-electronic components in a nuclear reactor requires a careful determination of the different components of the mixed gamma-neutron field. While the characterization of the neutron field can be performed using, for example, activation foils and validated by Monte-Carlo computation codes, the experimental measurement of the in-reactor gamma dose rate requires the use of costly ionization chambers. In this paper, we evaluate the possibility of using Red Perspex from Harwell Technologies for routine gamma dosimetry in mixed gamma neutron field. Self-powered gamma detectors and ionization chambers were used as reference dosimeters. We show that the accuracy of the Red 4034 dosimeters is better than 10% in mixed gamma-neutron fields.     

Factors affecting the radical scavenging activity of polyaniline

Polyaniline was chemically synthesized by oxidizing aniline with ammonium persulfate with and without hydrochloric acid (G-PANI and NR-PANI, respectively). NR-PANI and G-PANI were dedoped with ammonium hydroxide to yield NR-PANIdd and G-PANIdd. SEM images revealed a typical granular morphology for G-PANI and G-PANIdd, while NR-PANI, formed using a ‘falling pH method’, and NR-PANIdd, consisted of micro/nanorods and flakes. The samples were characterized using FTIR and the level of oxidation was determined by X-ray photoelectron spectroscopy (XPS). The surface area of the samples was measured by the BET method. The free radical scavenging activity, using the DPPH assay, showed the following ranking: NR-PANI > G-PANI ≈ NR-PANIdd > G-PANIdd. The radical scavenging activity of the polyanilines did not correlate with conductivity or surface area measurements, but was critically dependent upon the level of oxidation, and higher activity was obtained with the more reduced polyaniline samples.     

Review on impact analysis of FRP composites validated by LS‐DYNA

In recent decades fiber‐reinforced polymer (FRP) materials have revolutionized the world of engineering material. It has emerged as a substitute to traditional engineering material because of its aspect ratio. The increase in demand of FRP in various areas such as automotive and aerospace increases the need to do deep and diversified impact analysis of FRP composites. This article is an attempt to review literatures on the impact analysis of FRP composite validated by LS‐DYNA. The effect of projectile characterization, fiber orientation, and cores on the impact behavior of FRP composite has been discussed. An attempt is done to view literature from 1990s to present days. Because of insufficiency of relevant paper (using LS‐DYNA) in 1990s, this review article includes work done from 2000s to present days. Temperature dependency, energy absorbed, contact time, and damage pattern of the FRP laminates, along with future trend of research work in the area of composite are also discussed. POLYM. COMPOS., 36:1786–1798, 2015. © 2014 Society of Plastics Engineers     

Catalytic hydrotreatment of coal-derived residua

An investigation was conducted to determine the activities of various coal-liquefaction residua during catalytic hydrotreatment. Residua produced at low- and high-severity coal-liquefaction conditions were employed, as well as a nondeashed residuum produced at low-severity conditions. All experimental runs were performed in a continuous-flow hydrotreating unit using Shell 324M catalyst. Except for hydrogenation activity, catalyst activity declined with a typical S-shaped deactivation curve. The properties of the spent catalysts do not depend significantly upon prior processing of the feedstock; however, the prior processing history of the feedstocks affected their reactivity and the rate of catalyst deactivation. The results indicate beneficial effects of conducting coal liquefaction at low-severity conditions and of product deashing prior to catalytic hydrotreatment.     

Determination of trace metal content in corn oil by atomic absorption spectroscopy

Atomic absorption spectrophotometry is used for the determination of Cu, Fe, K, Na, Ni and Zn in industrial refined corn oil. The results of five different analytical techniques are compared. Fair agreement is obtained between the char-ashing method and the dilution proce-dure. Char ashing is a sensitive and useful technique, if handled correctly. Dilution, coupled to carbon-rod atomization, is a reliable method. To eliminate errors, due to sample loss, a proper injection technique is required. Extraction methods suffer from incomplete recoveries, owing to deficient break up of the organometallic com-pounds in oil