Low-surface-energy materials based on polybenzoxazines for surface modification of textiles

The benzoxazine monomers, 3-tert-butyl-3,4-dihydro-8-allyl-2H-1,3-benzoxazine (Benz-m) and 2,2-bis(3-methyl-3,4-dihydro-2H-1,3-benzoxazinyl) propane (Benz-b) were synthesized successfully using Mannich reaction. The formation of the monomer was confirmed by ¹H NMR and FTIR spectroscopy. Both the monomers were coated onto cotton fabric and the fabric samples were then dried at 60°C and cured at 120°C for varying time period. During the curing process, monomer was converted to polybenzoxazine by ring-opening polymerization of oxazine ring. In the Raman spectra, presence of the characteristic absorption bands due to benzoxazine structure at 952, at 1037 and at 1348?cm^?1 even after curing at 120°C for 2?h, suggested incomplete ring opening of benzoxazine to form polybenzoxazine. Also, the lack of durability of the finish to washing appears be due to the mild conditions of curing. Therefore, the application of Benz-b monomer was investigated on polyester (PET) fabric, which could be subjected to higher temperature however for shorter duration. The water and oil (ethylene glycol) repellency was measured to determine the hydrophobicity and oleophobicity of the finish on PET fabric. It was found that there was a marked improvement in the durability to laundry when compared with the treated cotton samples. This study provides a unique and easy method to prepare a low-surface-energy material through a simple thermal treatment procedure without using fluoro polymers or silicones.     

Effect of processing on nutraceutical properties of foxtail millet (<Emphasis Type="Italic">Setaria italica</Emphasis>) varieties grown in India

Six foxtail varieties grown in India were studied for their nutraceutical properties such as phenolics, tannins and antioxidant activity in whole, dehulled (10 and 17 %) and hulls (10 and 17 %) of the grain. Total antioxidant activity was estimated by three different assays viz., Ferric reducing antioxidant power (FRAP), 1,1-diphenyl-2-picryl-hydrazil radical scavenging activity (DRSA), and thiobarbituric acid reactive substances (TBARS). Among the six varieties, SiA-2593 had highest mean total phenolics (TP) (143.56 ± 55 μg PE/g), tannins (413.80 ± 58 mg/100 g), FRAP (1477.83 ± 26 μmol/g), DRSA (81.53 ± 6.9 %) and lowest TBARS (688.04 ± 39 %) followed by SiA-2644. Dehulling of the grain reduced TP by 24.64 and 43.11 %, tannins by 16.13 and 29.61 %, FRAP by 12.09 and 18.81 %, DRSA by 4.07 and 14.76 % and increase of TBARS by 45.29 and 58.21 % at 10 and 17 % dehulling. The hulls obtained after dehulling had higher percentage of TP, tannins, antioxidant activity (higher FRAP and DRSA and lower TBARS value), a positive correlation was observed between FRAP and Tannin (r = 0.90, P < 0.01) and TP (r = 0.86, P < 0.01) values and a negative correlation with TBARS (r = 0.85, P < 0.01). The results of the present study are useful in selecting the foxtail millet variety and processing conditions for development of functional and nutraceutical foods for various health benefits, however the functional properties of these varieties need to be studied.     

Utilization of industrial wastes and unprocessed micro-fillers for making cost effective mortars

The use of fly ash, slag, silica fume and marble dust as replacement of cement on the compressive strength and cost effectiveness of low w/c ratio superplasticized portland cement mortars was investigated. The blending of industrial wastes in mortars was also studied. Cement mortars (1:3 and 1:6) incorporating various proportions of industrial wastes were designed to have a flow of 110 ± 5%. The compressive strength of mortars with and without superplasticizer was determined at 1, 3, 7, 28 and 180 days and their cost effectiveness was analyzed.     

Synthesis of ZnO nanoparticles and study of their antibacterial and antifungal properties

In this paper, ZnO nanoparticles have been synthesized with and without the use of surfactants under different reaction conditions. The size of the ZnO nanoparticles varied in diameter (2 nm-28 nm) according to the reaction conditions employed. Promising particle size dependent antibacterial and antifungal activities of the ZnO nanoparticles have been observed. Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Infrared spectroscopy (FTIR) techniques were used to characterize the particle size and morphology.     

Structure and Function of Benzoylurea‐Derived α‐Helix Mimetics Targeting the Bcl‐xL/Bak Binding Interface

Targeting Bcl‐x _L /Bak : A family of rationally designed α‐helix mimetics with improved solubility and synthetic feasibility based on a benzoylurea scaffold is presented. These benzoylurea derivatives favor a linear conformation stabilized by an intramolecular hydrogen bond, and are able to mimic the spatial projection of the i, i+4, and i+7 residues of an α‐helix. Binding affinities of the benzoylurea derivatives to Bcl‐x_L have been assessed using fluorescence polarization competition assays and isothermal titration calorimetry.

     

Structural and spectroscopic analysis of thermally stable Dy3+ activated Na4Ca4Si6O18 phosphor for optoelectronic device applications

A series of yellow light-emitting Dy^3+-doped sodium calcium metasilicate (NCMS: Na₄Ca₄Si₆O₁₈) phosphors have been synthesized by adopting the conventional solid-state reaction route. Phase identification has been carried out through X-ray diffraction technique. The diffraction peaks of Na₄Ca₄Si₆O₁₈ sample are well-matched with the standard JCPDS (card no. 75-1687) pattern. Diffuse reflectance spectra have been used to determine the optical band gap of as-synthesized NCMS material. Morphological studies and particle size estimation have been done through scanning electron microscope. Under near UV excitation, photoluminescence (PL) spectra exhibit two characteristic bands with blue and yellow colour-emitting light. The concentration quenching was achieved beyond the 5.0 mol% of Dy³⁺ ion in NCMS host lattice. The temperature dependent PL studies display that the as-synthesized phosphor has high thermal stability. All investigations listed above demonstrate the tremendous potentiality of NCMS phosphor for optoelectronic device applications.

     

Effect of atmospheric pressure helium plasma on felting and low temperature dyeing of wool

Wool fabrics were treated with atmospheric pressure helium glow discharge plasma in an attempt to improve felting and dyeing behavior with cold brand reactive dyes using cold pad‐batch method at neutral pH. On glow plasma treatment, the hydrophilicity of wool surface and its resistance toward felting was greatly improved without any significant damage to the cuticle layer. The color strength of the plasma treated dyed wool on the surface (in terms of K/S) was found to be nearly double of the color strength of dyed untreated wool fabric. However, the corresponding total dye uptake of the treated wool increased by a much lower value of 40%–50%. The reason behind this altered dyeing behavior was investigated by studying the dye kinetics using infinite bath and surface characteristics using SEM and SIMS. It was found that the glow plasma treatment greatly transformed the chemical surface of the wool fibers. It resulted in uniform removal of hydrophobic cuticular layer, which resulted in better diffusion of the dye molecules into the fiber, and formation of hydrophilic ? NH₂ groups near the surface, which helped in anchoring the dye molecules close to the surface giving higher color strength than expected. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

废弃物回收系列专稿之一全球电子废物的研究(上)

本文第一部分综述了电子废物的基本情况,包括电子废物的定义、组成和估算电子废物产生量的方法。本文第二部分围绕电子废物管理的立法和相关提案进行论述。对部分国家存在的电子废物管理问题进行了识别。并以印度废印刷线路板提取铜的工艺为例,表明电子废物回收存在的风险。     

Energy and exergy analysis of a hybrid photovoltaic thermal double pass air collector

In this paper an attempt has been made to analyze the performance of semi transparent hybrid PVT double pass air collector. Based on the first law of thermodynamics, energy balance equations are for-mulated to derive the analytical expression for air temperature at the outlet, as a function of the design and climatic parameters for investigating the performance of semi transparent hybrid PVT air collector. The analysis is based on quasi-steady state condition. This paper shows the detailed analysis of energy and exergy of a semi transparent hybrid PVT double pass air collector and its comparison with single pass air collector for four weather conditions (a, b, c and d type) for five different cities (New Delhi, Bangalore, Mumbai, Srinagar, and Jodhpur) of India. It has been analyzed that if such systems are installed only at 10% of the total residential houses in Delhi, then the total carbon credits earned by the system is found to be Rs. 1767 millions in terms of thermal energy and Rs. 493 millions in terms of exergy for double pass air collector whereas Rs. 1528 millions in terms of thermal energy and Rs. 446 millions in terms of exergy for single pass air collector. The results clearly shows that hybrid PVT double pass air collector have better performance as compared to single pass air collector.     

Empirical Assessment of Bacillus Calmette-Guérin Vaccine to Combat COVID-19

COVID-19 has become one of the critical health issues globally, which surfaced first in latter part of the year 2019. It is the topmost concern for many nations’ governments as the contagious virus started mushrooming over adjacent regions of infected areas. In 1980, a vaccine called Bacillus Calmette-Guérin (BCG) was introduced for preventing tuberculosis and lung cancer. Countries that have made the BCG vaccine mandatory have witnessed a lesser COVID-19 fatality rate than the countries that have not made it compulsory. This paper’s initial research shows that the countries with a long-term compulsory BCG vaccination system are less affected by COVID-19 than those without a BCG vaccination system. This paper discusses analytical data patterns for medical applications regarding COVID-19 impact on countries with mandatory BCG status on fatality rates. The paper has tackled numerous analytical challenges to realize the full potential of heterogeneous data. An analogy is drawn to demonstrate how other factors can affect fatality and infection rates other than BCG vaccination only, such as age groups affected, other diseases, and stringency index. The data of Spain, Portugal, and Germany have been taken for a case study of BCG impact analysis.