Economical treatment of reverse osmosis reject of textile industry effluent by electrodialysis–evaporation integrated process

Membrane separation methods such as electrodialysis (ED) can reduce the volume load on evaporators by facilitating further concentration of rejects from reverse osmosis (RO) plants. ED studies were carried out on a bench-scale system using five membrane cell pairs to obtain a textile effluent concentrate containing approximately 6 times the quantity of salts present in the RO reject. The limiting current densities were determined to be in the range 2.15–3.35 amp/m² for feed flow rates varying from 18 to 108 L/h. Apart from feed rate, the influence of volume of concentrate and current on membrane performance was evaluated to optimize current utilization. An estimation of energy requirement of an integrated process constituting ED and evaporation for concentration of inorganics present in textile effluent from 4.35% to 24% was made and found to be approximately one eighth of the operating cost incurred by evaporation alone. Detailed design of a commercial ED system revealed that a membrane area of 13.1 m² was required to treat a feed rate of 1500 L/h. The payback period to recover capital investment was found to be 110 days.     

External stimulus-responsive biomaterials designed for the culture and differentiation of ES,iPS, and adult stem cells

The physical and chemical characteristics of biomaterial surface and hydrogels can be altered by external stimuli, such as light irradiation, temperature changes, pH shifts, shear stress forces, electrical forces, and the addition of small chemical molecules. Such external stimulus-responsive biomaterials represent promising candidates that have been developed for the culture and differentiation of embryonic stem (ES) cells, induced pluripotent stem (iPS) cells, and adult stem cells. Biomaterials that are designed to respond in a reversible manner to specific external signals can be formed on micropatterned or non-micropatterned surface, in hydrogels, or on microcarriers. Stem cells and the cells differentiated from them into specific tissue lineages can be cultured and/or differentiated on dishes with immobilized external stimulus-responsive polymers. Cells can be detached from these dishes without using an enzymatic digestion method or a mechanical method when the appropriate external stimulus is generated on the surface. This review discusses the polymers and polymeric designs employed to produce surface and hydrogels for stem cell culture, differentiation, and/or cell detachment using various external stimuli.     

Nanocomposites based on transition metal oxides in polyvinyl alcohol for EMI shielding application

In the present work, the nanocomposites based on different transition metal oxides like iron oxide (Fe₂O₃), zinc oxide (ZnO), silicon dioxide (SiO₂), zirconium dioxide (ZrO₂), and titanium dioxide (TiO₂) in PVA matrix have been studied for their suitability as electromagnetic interference (EMI) shielding materials in the frequency range of 4–8 GHz (C-band) and 8–12 GHz (X-band). The nanocomposites containing 0.1, 0.5, 1.0, 5.0, and 10.0 wt% of oxides in the matrix were synthesised by solvent casting method. The EMI attenuation studies in 4–12 GHz frequency range were carried out using the Vector Network Analyzer R & S: ZVA40 method by measuring the loss due to reflection. The minimum reflectivity values for the composites containing Fe₂O₃, ZnO, SiO_2, ZrO₂, and TiO₂ in PVA matrix at 10 wt% concentration level in the matrix were found to be ?38.85 dB (10.4 GHz), ?33.65 dB (10.4 GHz), ?41.90 dB (10.4 GHz), ?24.90 dB (11.0 GHz), and ?32.90 dB (9.76 GHz), respectively. Based on these results, the SiO₂- and Fe₂O₃-based composites, which also exhibit high thermal stability and mechanical strength, are found to be low-cost and efficient EMI shielding materials.     

Metazoans and Intrinsic Apoptosis: An Evolutionary Analysis of the Bcl-2 Family

The B-cell lymphoma-2 (Bcl-2) family is a group of genes regulating intrinsic apoptosis, a process controlling events such as development, homeostasis and the innate and adaptive immune responses in metazoans. In higher organisms, Bcl-2 proteins coordinate intrinsic apoptosis through their regulation of the integrity of the mitochondrial outer membrane; this function appears to have originated in the basal metazoans. Bcl-2 genes predate the cnidarian-bilaterian split and have been identified in porifera, placozoans and cnidarians but not ctenophores and some nematodes. The Bcl-2 family is composed of two groups of proteins, one with an α-helical Bcl-2 fold that has been identified in porifera, placozoans, cnidarians, and almost all higher bilaterians. The second group of proteins, the BH3-only group, has little sequence conservation and less well-defined structures and is found in cnidarians and most bilaterians, but not porifera or placozoans. Here we examine the evolutionary relationships between Bcl-2 proteins. We show that the structures of the Bcl-2-fold proteins are highly conserved over evolutionary time. Some metazoans such as the urochordate Oikopleura dioica have lost all Bcl-2 family members. This gene loss indicates that Bcl-2 regulated apoptosis is not an absolute requirement in metazoans, a finding mirrored in recent gene deletion studies in mice. Sequence analysis suggests that at least some Bcl-2 proteins lack the ability to bind BH3-only antagonists and therefore potentially have other non-apoptotic functions. By examining the foundations of the Bcl-2 regulated apoptosis, functional relationships may be clarified that allow us to understand the role of specific Bcl-2 proteins in evolution and disease.     

Composition and Recyclability Analysis of Poly(Vinyl Chloride) Recovered from Computer Power Cables and Commercial Wires

The product‐based recycling of the electrical and electronic devices and their by‐products are limited due to their complex characteristics and dissimilar material characteristics. However, such recycling procedures give clear ideas about the composition and possible recycling options of the materials present in them. Consequently, the present study deals with isolation and recycling of the major polymeric fraction present in the waste computer power supply cables (CPS) and electrical power supply (EPS) wires isolated from the household items. The composition analysis of CPS and EPS indicates that the poly(vinyl chloride) (PVC) is the major polymeric fraction along with minor content of polyethylene (PE) and polycarbonate (PC). Further, this research compares the mechanical recyclability of the PVC recovered from the CPS and EPS. Among the PVC's analyzed, PVC isolated from the EPS has been indicated superior mechanical properties. Similarly, thermal degradation analysis (TGA) indicated higher thermal stability for the PVC isolated from EPS. Besides, the flammability of the PVC specimens was studied and concluded with the possible mechanism occurring during combustion. Moreover, this study points out that PVC recovered from EPS and CPS can be mechanically recycled for the elimination of the waste. J. VINYL ADDIT. TECHNOL., 26:213–223, 2020. © 2019 Society of Plastics Engineers     

Permeability characterization. Part 1: A proposed standard reference fabric for permeability

A three-dimensionally woven fabric is proposed as a standard reference material for permeability characterization. The 3-D woven fabric requires care in cutting and handling, although it is more robust than 2-D woven or braided fabrics. If prepared carefully, the permeability of the 3-D woven fabric can be measured reproducibly within 15% in either radial flow or saturated 1-D flow geometries. The material was characterized for permeability in radial, unsaturated and saturated 1-D, and through-thickness flow geometries. The transient results demonstrated the importance of structural heterogeneity on the unsaturated flow behavior, and agree qualitatively with a simplistic model of flow in heterogeneous unsaturated porous media. The effects of heterogeneity were manifested in the proposed SRM by an increasing trend in the “unsaturated permeability.” Experiments were also conducted with a random mat that displayed transient flows dominated by wicking. The effects of wicking on the macroscopic flow behavior were manifested by transients in the “unsaturated permeability” in which a decreasing trend was observed.     

Preparation,Characterization, and Dielectric Properties of PP/CaTiO3 Composites for Microwave Substrate Applications

Calcium titanate (CaTiO₃) filled polypropylene (PP) composites have been fabricated through compression molding method. The phase purity of the PP/CaTiO₃ composites was studied using X‐ray diffraction studies. Scanning electron microscopy technique has been employed to study the dispersion of the particulate filler in the PP matrix. The dielectric constant and loss tangent of the composites were measured at X‐band frequency region using waveguide cavity perturbation technique. PP/CaTiO₃ composite has an effective dielectric constant of 11.74 and loss tangent 0.007 at optimum filler loading. The experimental dielectric constant of filled composites was compared with theoretically predicted dielectric constant values obtained using different modeling approaches. The linear coefficient of thermal expansion of PP/CaTiO₃ composites was studied using thermomechanical analyzer.     

Suppression of fuel and air stream diluted methane–air partially premixed flames in normal and microgravity

The effects of fuel and air stream dilution (ASD) with carbon dioxide on the suppression of normal and microgravity laminar methane–air partially premixed coflow jet flames were experimentally and numerically investigated. Experiments were conducted both in our normal-gravity laboratory and at the NASA Glenn Research Center 2.2 s drop tower. Measurements included flame topology and liftoff heights of diluted flames, critical diluent mole fractions for flame blowout, and the radiant heat loss from flames. The flames were also simulated using an axisymmetric unsteady numerical code that utilizes detailed chemistry and transport models. In addition, counterflow flame simulation results were used to examine similitude between the counterflow and coflow flame suppression, and further characterize the effectiveness of fuel stream versus ASD on flame extinction. A smaller relative fuel stream dilution (FSD) extinguishes partially premixed flames (PPFs) with increasing premixing as compared to dilution of the air stream. Conversely, smaller ASD is required to extinguish PPFs as they become less premixed and approach nonpremixed (NP) behavior. Fuel stream diluted PPFs and air stream diluted NP flames extinguish primarily through a reactant dilution effect while fuel stream diluted NP flames and air stream diluted PPF are extinguished primarily by a thermal cooling effect. Normal gravity flames lift off and blow out with a smaller diluent mole fraction than microgravity flames. The difference between the fuel and ASD effectiveness increases as the gravitational acceleration is reduced. Radiation heat losses are observed to increase with increasing diluent mole fraction and decreasing gravity.     

Recursive Technique For Computing System Reliability

This paper presents a simple recursive formula for calculating source-to-sink congestion, and hence reliability, in a network. This congestion is derived from individual blocking probabilities of each link. The method has an advantage of not requiring cut-sets. Such a knowledge is a prerequisite in most other methods of reliability analysis. We have programmed the algorithm using Pascal as it allows recursive procedure calls. An example illustrates the method.