Structure and Function of Glucose Binding Protein–Single Walled Carbon Nanotube Complexes

Understanding the structure and function of glucose binding proteins (GBP) complexed with single walled carbon nanotubes (SWNTs) is important for the development of applications including fluorescent sensors and nanostructure particle tracking. Herein, circular dichroism (CD), thermal denaturation, photo‐absorption spectroscopy and atomic force microscopy are used to study these nanostructures. The protein retains its glucose‐binding activity after complexation and is thermally stable below 36 °C. However, the SWNT lowers the midpoint denaturation temperature (T_m) by 5 °C and 4 °C in the absence and presence of 10 mM glucose, respectively. This data highlights that using techniques such as CD and thermal denaturation may be necessary to fully characterize such protein‐nanomaterial nanostructures.     

Parameter-uniform hybrid numerical scheme for time-dependent convection-dominated initial-boundary-value problems

In this paper, we propose a numerical scheme which is almost second-order spatial accurate for a one-dimensional singularly perturbed parabolic convection-diffusion problem exhibiting a regular boundary layer. The proposed numerical scheme consists of classical backward-Euler method for the time discretization and a hybrid finite difference scheme for the spatial discretization. We analyze the scheme on a piecewise-uniform Shishkin mesh for the spatial discretization to establish uniform convergence with respect to the perturbation parameter. Numerical results are presented to validate the theoretical results.     

Corrosion behavior of metals and alloys in marine-industrial environment

This work deals with atmospheric corrosion to assess the degrading effects of air pollutants on ferrous and non-ferrous metals and alloys, which are mostly used as engineering materials. An exposure study was conducted in the Tuticorin port area located on the east coast of South India, in the Gulf of Mannar with Sri Lanka to the southeast. Common engineering materials, namely mild steel, galvanized iron, Zn, Al, Cu and Cu–Zn alloys (Cu–27Zn, Cu–30Zn and Cu–37Zn), were used in the investigation. The site was chosen where the metals are exposed to marine and industrial atmospheres. Seasonal 1 to 12 month corrosion losses of these metals and alloys were determined by a weight loss method. The weight losses showed strong corrosion of mild steel, galvanized iron, Cu and Zn and minor effect on Al and Cu–Zn alloys. Linear regression analysis was conducted to study the mechanism of corrosion. The composition of corrosion products formed on the metal surfaces was identified by x-ray diffraction and Fourier transform infrared spectroscopy.     

Study of variables affecting the synthesis of biodiesel from Madhuca Indica oil

Biodiesel derived from non‐edible Madhuca Indica oil (MIO) seems to be a better alternative to diesel oil in India. In the present work, effects of reaction variables such as mass ratio of methanol to oil, catalyst concentration, reaction time and reaction temperature on biodiesel yield were studied. The acid value of the commercially available MIO is high, and hence a two‐step process was used to produce biodiesel from MIO. In the first step, the acid value of the MIO was reduced to less than 1 mg KOH/g, using acid‐catalyzed transesterification. In the second step, the pretreated MIO was converted to biodiesel using alkaline‐catalyzed transesterification. From the experimental results, it is observed that the optimized conditions for biodiesel production are a 1 : 4 mass ratio of methanol to oil, 55 °C reaction temperature, 120 min of reaction time, and 1% sodium hydroxide catalyst. The properties of the MIO biodiesel were found to be within the biodiesel limits of the European Union. Hence, the MIO biodiesel can be used as a substitute for diesel for the sustainable development of rural areas and as a renewable fuel.     

Evaluation of precipitates used in strainer head loss testing: Part III. Long-term aluminum hydroxide precipitation tests in borated water

Long-term aluminum (Al) hydroxide precipitation tests were conducted in slightly alkaline solutions containing 2500 ppm boron. The solution temperature was cycled to obtain a temperature history more representative of emergency core cooling system temperatures after a loss-of-coolant accident. The observed Al precipitation boundary was close to predicted results for amorphous precipitates, which are higher than the solubility expected for crystalline forms. Bench-scale and loop head loss test results under various conditions were successfully combined into single map in a temperature - ‘pH + p[Al]_T’ domain, which yielded two bounding lines for Al hydroxide solubility in borated alkaline water that depend on whether or not loop head loss tests with Al alloy coupons are included. Precipitates were observed to form either as fine, cloudy suspensions, which showed very little tendency to settle, or as flocculated precipitates. The flocculation tendency of the precipitates can be qualitatively explained by a colloid stability theory or a phase diagram for protein solutions.     

Influence of sodium environment on the uniaxial tensile behavior of titanium modified type 316 stainless steel

True stress-true strain tensile data have been obtained for titanium modified type 316 stainless steel in the solution annealed condition and after exposure to a flowing sodium environment at temperature of 700, 650, 600 and 550°C. The specimens were exposed to sodium for times between 120 and 5012 h to produce carbon penetration depths in the range 0.05–0.30 mm. The Voce equation was used to describe tensile flow curves for plastic strains above 0.005. The results showed that, when compared with solution annealed specimens, the tensile flow behavior of the sodium exposed specimens is characterized by a higher strain hardening rate, which decreases rapidly as the flow stress increases. The loss in tensile ductility of the material due to carburization in sodium environment was found to be minimal.     

Effect of menthol coated craft paper on corrosion of copper in HCl environment

Natural menthol was coated on craft paper by impregnation and studied as volatile corrosion inhibitor for copper in hydrochloric acid environment. The effect of menthol on copper corrosion was studied by gravimetric and electrochemical methods such as potentiodynamic polarization and electrochemical impedance measurements. The results indicate that menthol adsorbs on the metal surface, which protects copper against further corrosion. The adsorption behaviour of menthol on copper surface was found to obey Temkin’s adsorption isotherm.     

Adsorption of chromium (VI) on functionalized and non-functionalized carbon nanotubes

We did a comparative study on the adsorption capacity of Cr (VI) between functionalized carbon nanotubes (CNTs) and non-functionalized CNTs. The statistical analysis reveals that the optimum conditions for the highest removal of Cr (VI) are at pH 9, with dosage 0.1 gram, agitation speed and time of 120 rpm and 120 minutes, respectively. For the initial concentration of 1.0 mg/l, the removal efficiency of Cr (VI) using functionalized CNTs was 87.6% and 83% of non-functionalized CNTs. The maximum adsorption capacities of functionalized and non-functionalized CNTs were 2.517 and 2.49 mg/g, respectively. Langmuir and Freundlich models were adopted to study the adsorption isotherm, which provided a K _L and K _F value of 1.217 L/mg and 18.14 mg^1?n L ⁿ /g functionalized CNT, while 2.365 L/mg and 2.307 mg^1?n L ⁿ /g for non-functionalized CNTs. This result proves that functionalized CNTs are a better adsorbent with a higher adsorption capacity compared with the non-functionalized CNTs.     

Thermal hydraulic investigations of primary coolant pipe rupture in an LMFBR

High quality for primary coolant pipes in fast reactors is ensured through utmost care taken in the design and manufacture. Demonstration of high structural reliability of them by extensive experimental and theoretical studies renders the double-ended guillotine rupture (DEGR) of a primary pipe a highly improbable event. However, as a defense in depth approach instantaneous DEGR of one of the pipes has been considered in design. Thermal hydraulic analyses of this event in a typical liquid metal cooled fast breeder have been carried out to study its consequences and to establish the availability of safety margins. Various uncertainties relevant to the event have been analysed to evaluate the sensitivity of each parameter. For this purpose, one-dimensional plant dynamics studies using thermal and hydraulic models of core subassemblies and primary sodium circuit have been performed. Validity of the assumptions made in the one-dimensional model like, uniform flow through all subassemblies in core under pipe ruptured condition and non possibility of sodium boiling by flashing have also been investigated through detailed three-dimensional and pressure transient studies. Analyses indicate the availability of good margins against the design safety limits in all the parametric cases analysed.