Graphene: A Reusable Substrate for Unprecedented Adsorption of Pesticides

Unprecedented adsorption of chlorpyrifos (CP), endosulfan (ES), and malathion (ML) onto graphene oxide (GO) and reduced graphene oxide (RGO) from water is reported. The observed adsorption capacities of CP, ES, and ML are as high as ～1200, 1100, and 800 mg g^?1, respectively. Adsorption is found to be insensitive to pH or background ions. The adsorbent is reusable and can be applied in the field with suitable modifications. A first‐principles pseudopotential‐based density functional analysis of graphene–water–pesticide interactions showed that the adsorption is mediated through water, while direct interactions between graphene and the pesticides is rather weak or unlikely.     

Carbon nanotube-textured sand for controlling bioavailability of contaminated sediments

Sand particles textured with multi-walled carbon nanotubes (MWCNTs) can efficiently control the mobility and bioavailability of contaminants found in aquatic sediments. Adsorption measurements for a wide variety of aquatic contaminants (chlorinated hydrocarbons) on MWCNT-textured sand showed orders of magnitude increase in their sorption coefficients compared to traditional materials (sand) when used for physically separating contaminated sediments from overlying water. Molecular dynamics simulations performed on model experimental systems emphasize that the hydrophobic interactions of the MWCNT surfaces play a crucial role in driving the water molecules away, promoting such enhanced contaminant uptake. The MWCNT-textured sand significantly reduced the migration of contaminants from sediments to overlying water and possesses suitable parameters needed for contaminant sequestration and sediment remediation technologies. The single step and scalable procedure described here for synthesizing robust MWCNT-textured sand surfaces will provide important improvements in the field of remediation/aquatic environment restoration technologies.     

Structural and electrical properties of fritless Ni(1?x)CuxMn2O4 (0?≤?x?≤?1) thick film NTC ceramic

Spinel structured NTC thermistor Ni_(1−x)Cu _x Mn₂O₄ (0 ≤ x ≤ 1) ceramics was prepared by oxalic precursor method and fritless thick films screen printed on alumina. The composition dependent structural and electrical properties are reported in this paper. The results show that with increasing copper ion substitution both Cu²⁺ and Mn⁴⁺ predominantly occupy the octahedral site. The concentration of Cu²⁺ ions in octahedral site increases while that of Ni²⁺ ions decreases linearly. The thick film Ni_(1−x)Cu _x Mn₂O₄ ceramic comply with Arrhenius equation. A thermistor constant of ~1,200 K has been obtained for fritless thick film NTC ceramics using inorganic binders in the RT/90 thermal range.     

Evaluating Authentication Schemes for Real-Time Data in Wireless Sensor Network

There have been discussed many user authentication schemes for wireless sensor networks. This paper intends to review the existing authentication techniques for their pros and cons. The techniques are primarily classified on the basis of factors used therein that include one-factor, two-factor, and three-factor schemes. Twelve architecture models on which various authentication schemes are based. The pros and cons of models are also discussed. The security and functionality feature is also used as criteria for evaluation metrics. In this paper, we have also considered various one-factor, two-factor and three-factor authentication scheme. The communication, computation cost, security feature and the security tool are the most important criteria for comparing the authentication techniques. This whole analysis can be used by other researchers to design their own authentication schemes considering the stated criteria.

     

Topographical changes in polyester after chemical,physical and enzymatic hydrolysis

Polyester was treated with alkali, VUV excimer, and a hydrolytic enzyme. The effect of each treatment on the physicochemical properties of polyester (PET) was studied and compared by qualitative and quantitative methods. Scanning electron microscopy and atomic force microscopy analysis show that alkali treatment causes severe fiber degradation with formation of pits on the fabric surface. In contrast, excimer treatment results in uniform pitting at nanometer level, which is restricted to the surface. In case of enzyme-treated samples, non-uniform roughness was observed due to deposition of residual protein formed due to enzyme hydrolysis. K/S value and moisture regain value of excimer-treated samples were found to be higher than alkali- or enzyme-treated PET. Out of the three methods, excimer treatment appears to be the best method for PET modification with maximum number of polar groups being created on hydrolysis with marginal loss in strength and weight.     

Age-related decline in macrophage and lymphocyte functions in mice and its alleviation by treatment with probiotic Dahi containing Lactobacillus acidophilus and Bifidobacterium bifidum

This study evaluated the effects of probiotic Dahi administration in ageing mice on macrophage and lymphocyte functions. Probiotic Dahi were prepared by co-culturing in buffalo milk (3% fat) Dahi bacteria (Lactococcus lactis ssp. cremoris NCDC-86 and Lc. lactis ssp. lactis biovar diacetylactis NCDC-60) along with Lactobacillus acidophilus LaVK2 (La-Dahi) or combined Lb. acidophilus and Bifidobacterium bifidum BbVK3 (LaBb-Dahi). Four groups of 12 mo old mice were fed for four months, with the supplements (5 g/day) of buffalo milk (3% fat), Dahi, La-Dahi and LaBb-Dahi, respectively, in addition to basal diet, and a fifth group that received no supplements served as control. The immune functions of young mice (4 mo old) were also compared with those of ageing adult mice (16 mo old). The production of nitric oxide and cytokines IL-6 and TNF-α declined and that of immunosuppressive prostaglandin E2 (PGE2) increased by stimulated peritoneal and splenic macrophages in ageing mice, compared with their young counterparts. The proliferation of stimulated splenocytes diminished and the production of IL-2 decreased and that of IL-6 and TNF-α enhanced in ageing compared with young mice. Feeding ageing mice with La-Dahi or LaBb-Dahi improved peritoneal macrophage functions stimulating nitric oxide and IL-6 and diminishing PGE2 production. Feeding La-Dahi or LaBb-Dahi also improved lymphocyte functions stimulating their proliferation and production of IL-2 in ageing mice. To conclude, the probiotic La-Dahi and LaBb-Dahi are effective in reversing age related decline in immune functions in mice.     

High frequency electromagnetism, heat transfer and fluid flow coupling in ANSYS multiphysics.

The goal of this study was to numerically predict the temperature of a liquid product heated in a continuous-flow focused microwave system by coupling high frequency electromagnetism, heat transfer, and fluid flow in ANSYS Multiphysics. The developed model was used to determine the temperature change in water processed in a 915 MHz microwave unit, under steady-state conditions. The influence of the flow rates on the temperature distribution in the liquid was assessed. Results showed that the average temperature of water increased from 25 degrees C to 34 degrees C at 2 l/min, and to 42 degrees C at 1 l/min. The highest temperature regions were found in the liquid near the center of the tube, followed by progressively lower temperature regions as the radial distance from the center increased, and finally followed by a slightly higher temperature region near the tube's wall corresponding to the energy distribution given by the Mathieu function. The energy distribution resulted in a similar temperature pattern, with the highest temperatures close to the center of the tube and lower at the walls. The presented ANSYS Multiphysics model can be easily improved to account for complex boundary conditions, phase change, temperature dependent properties, and non-Newtonian flows, which makes for an objective of future studies.