Destruction of percolative network using green synthesized gold nanoparticles: Formation of high dielectric material

Gold nanoparticles (AuNPs) of about 5 nm in diameter were biosynthesized at room temperature (300 K). The PVA/2.5 wt% KH₂PO₄ or KDP composite film and PVA/2.5 wt% KDP/AuNPs nanocomposite films with different concentrations of AuNPs were prepared. Interestingly, addition of 0.05 wt% of AuNPs to the PVA/2.5 wt% KDP percolative composite film destroys percolative behavior of this composite film. Furthermore, the PVA/2.5 wt% KDP/0.05 wt% AuNPs nanocomposite film exhibited high room temperature dielectric permittivity (ε′ ∼ 590 at 1 kHz). The behavior of AC conductivity (σ_ac) of the nanocomposite films indicated correlated barrier hopping type of conduction mechanism. The Cole–Davidson dielectric response becomes evident as the interfacial polarization process acquires a more symmetric form, tending to Debye relaxation. High value of ε′ promises direct application in capacitors. Moreover, the novel feature of destroying the percolative behavior by AuNPs may be applied even in other systems.     

Mechanisms of EGFR Resistance in Glioblastoma

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. Despite numerous efforts to target epidermal growth factor receptor (EGFR), commonly dysregulated in GBM, approaches directed against EGFR have not achieved the same degree of success as seen in other tumor types, particularly as compared to non-small cell lung cancer (NSCLC). EGFR alterations in glioblastoma lie primarily in the extracellular domain, unlike the kinase domain alterations seen in NSCLC. Small molecule inhibitors are difficult to develop for the extracellular domain. Monoclonal antibodies can be developed to target the extracellular domain but must contend with the blood brain barrier (BBB). We review the role of EGFR in GBM, the history of trialed treatments, and the potential paths forward to target the pathway that may have greater success.     

Exploring the Bioactive Potentials of C60-AgNPs Nano-Composites against Malignancies and Microbial Infections

At present, the potential role of the AgNPs/endo-fullerene molecule metal nano-composite has been evaluated over the biosystems in-vitro. The intra-atomic configuration of the fullerene molecule (C₆₀) has been studied in-vitro for the anti-proliferative activity of human breast adenocarcinoma (MDA-MB-231) cell lines and antimicrobial activity against a few human pathogens that have been augmented with the pristine surface plasmonic electrons and antibiotic activity of AgNPs. Furthermore, FTIR revealed the basic vibrational signatures at ~3300 cm⁻¹, 1023 cm⁻¹, 1400 cm⁻¹ for O-H, C-O, and C-H groups, respectively, for the carbon and oxygen atoms of the C₆₀ molecule. NMR studies exhibited the different footprints and magnetic moments at ~7.285 ppm, explaining the unique underlying electrochemical attributes of the fullerene molecule. Such unique electronic and physico-chemical properties of the caged carbon structure raise hope for applications into the drug delivery domain. The in-vitro dose-dependent application of C₆₀ elicits a toxic response against both the breast adenocarcinoma cell lines and pathogenic microbes. That enables the use of AgNPs decorated C₆₀ endo fullerene molecules to design an effective anti-cancerous drug delivery and antimicrobial agent in the future, bringing a revolutionary change in the perspective of a treatment regime.     

Identification of Species Origin of Meat and Meat Products on the DNA Basis: A Review

The adulteration/substitution of meat has always been a concern for various reasons such as public health, religious factors, wholesomeness, and unhealthy competition in meat market. Consumer should be protected from these malicious practices of meat adulterations by quick, precise, and specific identification of meat animal species. Several analytical methodologies have been employed for meat speciation based on anatomical, histological, microscopic, organoleptic, chemical, electrophoretic, chromatographic, or immunological principles. However, by virtue of their inherent limitations, most of these techniques have been replaced by the recent DNA-based molecular techniques. In the last decades, several methods based on polymerase chain reaction have been proposed as useful means for identifying the species origin in meat and meat products, due to their high specificity and sensitivity, as well as rapid processing time and low cost. This review intends to provide an updated and extensive overview on the DNA-based methods for species identification in meat and meat products.     

Effective solar power harnessing using a few novel solar tree designs and their performance assessment

Solar irradiance being considered as one of the most important alternative sources of energy can be harnessed in the form of electrical power using photovoltaic panels erected under the sun. Optimum conversion of power from solar panels can be obtained by using Maximum Power Point Tracking (MPPT), which involves continuously adjusting the angle of panels according to the change in the angle of falling irradiance. These trackers, however, use some amount of power for operation of MPPT equipment. Various techniques for arranging the solar panels in three dimensions have been suggested for optimizing the output power from them. The inspiration behind arranging the panels are often drawn from the natural trees where the branches and the leaves follow a particular pattern called phyllotaxy which is directly analogous to the Fibonacci number and Golden ratio. In this research work, the power output from two solar tree models based on 3/8 and 2/5 phyllotaxy pattern and solar conventional panel compared under similar irradiance conditions. There are so many phyllotaxy patterns like 1/3, 2/5, 3/8, etc. When the solar panels aligned in different phyllotaxies, then the orientation direction of solar panels are distinct. Each solar panel connected in solar trees is in a different direction, so that they received the maximum amount of sunlight throughout the day as compared to conventional panels which is oriented unidirectional.     

Direct simulation of turbulent heat transfer in swept flow over a wire in a channel

We investigate heat transfer characteristics of a turbulent swept flow in a channel with a wire placed over one of its walls using direct numerical simulation. This geometry is a model of the flow through the wire-wrapped fuel pins, the heat exchanger, typical of many civil nuclear reactor designs. The swept flow configuration generates a recirculation bubble with net mean axial flow. A constant inward heat flux from the walls of the channel is applied. A key aspect of this flow is the presence of a high temperature region at the contact line between the wire and the channel wall, due to thermal confinement (stagnation). We analyze the variation of the temperature in the recirculation bubble at Reynolds number based on the bulk velocity along the wire-axis direction and the channel half height of 5400. Four cases are simulated with different flowrates transverse to the wire-axis direction. This configuration is topologically similar to backward-facing steps or slots with swept flow, except that the dominant flow is along the obstacle axis in the present study and the crossflow is smaller than the axial flow, i.e., the sweep angle is large. The temperature field is simulated at three different Prandtl numbers: 10^?2, 10^?1 and 1. The lower value of Prandtl number is characteristic of experimental high-temperature reactors that use a molten salt as coolant while the high value is typical of gas (or water vapor) heat exchangers. In addition, mean temperature, turbulence statistics, instantaneous wall temperature distribution and Nusselt number variation are investigated. The peak Nusselt number occurs close to the reattachment location, on the lee side of the wire, and is about 50–60% higher compared to the case without crossflow. The high temperature region follows the growth of the recirculation bubble which increases by about 65% from the lowest to highest amount of crossflow. Particular attention is devoted to the temperature distribution on the walls of the channel and the surface of the wire. The behavior of the heat-flux across the mean dividing streamline of the recirculation bubble is investigated to quantify the local heat transfer rates occurring in this region.     

Impacts of conservation agriculture on soil aggregation and aggregate-associated N under an irrigated agroecosystem of the Indo-Gangetic Plains

We evaluated impacts of conservation agriculture (zero tillage, bed planting and residue retention) on changes in total soil N (TSN) and aggregate-associated N storage in a sandy loam soil of the Indo-Gangetic Plains. Cotton (Gossypium hirsutum) and wheat (Triticum aestivum) crops were grown during the first 3 years (2008–2011) and in the last year, maize (Zea mays) and wheat were cultivated. Results indicate that after 4 years the plots under zero tillage with bed planting (ZT-B) and zero tillage with flat planting (ZT-F) had 15 % higher TSN concentrations than conventional tillage and bed planting plots (CT-B) (0.63 g kg^?1 soil) in the 0–5 cm soil layer. CT-B plots had lower soil bulk density that ZT plots in that layer. Plots under ZT-B (0.57 Mg ha^?1) contained 20 % higher TSN stock in the 0–5 cm soil layer than CT-B plots (0.48 Mg ha^?1). However, tillage had no impact on TSN concentration or stock in the sub-surface (5–15 and 15–30 cm) soil layers. Thus, in the 0–30 cm soil layer, ZT-B plots contained 6 and 5 % higher (P > 0.05) TSN stock compared with CT-B (2.15 Mg N ha^?1) and CT-F (2.19 Mg N ha^?1) plots respectively after 4 years. Plots that received cotton/maize + wheat residue (C/M + W RES) contained 16 % higher TSN concentration than plots with residues removed (N RES; 0.62 g kg^?1 soil) in the surface (0–5 cm) layer. Plots with only cotton/maize residue (C/M RES) or only wheat residue (W RES) retention/incorporation had similar TSN concentrations and stocks in the subsurface layer. Plots under ZT-B also had more macroaggregates (0.25–8 mm) and greater mean weight diameter with lower silt + clay sized particles than CT-B plots in that layer. A greater proportion of large macroaggregates (2–8 mm) in the plots under C/M + W RES compared with N RES were observed. In the 5–15 cm soil layer ZT-B and C/M + W RES treated plots had more macroaggregates and greater mean weight diameter than CT-B and N RES treated plots, respectively. Because of the greater amount of large aggregates, plots under ZT-B and C/M + W RES had 49 and 35 % higher large macroaggregate-associated N stocks than CT-B (38 kg TSN ha^?1) and N RES (40 kg TSN ha^?1) plots, respectively, in the 0–5 cm soil layer, although aggregates had similar TSN concentrations in all plots. Both tillage and residue retention had greater effects on aggregate-associated N stocks in the 5–15 cm layers. In addition to N content within large macroaggregates, small macroaggregate-associated N contents were also positively affected by ZT-B and C/M + W RES. Tillage and residue retention interaction effects were not significant for all parameters. Thus, the adoption of ZT in permanent beds with crop residue addition is a better management option for improvement of soil N (and thus possibly a reduced dose of fertilizer N can be adopted in the long run), as the management practice has the potential to improve soil aggregation with greater accumulation of TSN within macroaggregates, and this trend would likely have additive effects with advancing years of the same management practices in this region.     

Thermoelastic study of a functionally graded annular fin with variable thermal parameters using semiexact solution

Abstract

In this paper, the thermoelastic behavior of a functionally graded material (FGM) annular fin is investigated. The material properties of the annular fin are assumed to vary radially. The heat transfer coefficient and internal heat generation are considered to be functions of temperature. A closed form solution of nonlinear heat transfer equation for the FGM fin is obtained using the homotopy perturbation method (HPM) which leads to nonuniform temperature distributions within the fin. The temperature field is then coupled with the classical theory of elasticity and the associated thermal stresses are derived analytically. For the correctness of the present closed form solution for the stress field, the results are compared with the ANSYS-based finite element method (FEM) solution. The present HPM-based closed form solution of the stress field exhibits a good agreement with the FEM results. The effect of various thermal parameters such as the thermogeometric parameter, conduction-radiation parameter, internal heat generation parameter, coefficient of variation of thermal conductivity, and the coefficient of thermal expansion on the thermal stresses are discussed. The results are presented in both nondimensional and dimensional form. The dimensional stress analysis discloses the suitability of FGM as the fin material in practical applications.     

Self generating square/triangular wave and pulse width modulator using a single MO-CCCDTA

A self-generating square/triangular wave and pulse width modulator (PWM) using multiple output current controlled current differencing transconductance amplifier (MO-CCCDTA) is presented. To obtain all the three functions simultaneously from the same topology, the MO-CCCDTA is modified a little bit. The characterisation of the modified MO-CCCDTA structure shows that the parasitic resistances at input terminals (n and p) can be varied via bias current. The maximum useful frequency range is found to be 635 MHz, which is higher than the available literature. The waveform generator and PWM circuit use only one MO-CCCDTA, one grounded capacitor and no resistor; hence suitable for IC implementation. The duty cycle of proposed pulse width modulation can be tuned by bias current of MO-CCCDTA over a wide range. The performances of the proposed block and its applications (square/triangular/PWM) are verified by PSPICE simulation using TSMC 0.35 µm technology. The power consumption is about 1.12 mW. To verify experimentally, a prototype of MO-CCCDTA has been made using commercially available ICs (AD844AN and CA3080) on printed circuit board. The simulation and experimental results verify theoretical proposition well. Monte carlo simulation is carried out, which proves satisfactory performance of the proposed circuit against mismatches. The performance of the proposed circuit is also verified through pre-layout and post-layout simulation results. The required chip area is only 22.415 × 14.6 µm².     

A novel electronic micro-viscometer

Microsystem Technologies - This paper reports the development of a novel electronic micro-viscometer capable of measuring viscosity of different Newtonian fluids using less than 100 µl which...