Synthesis and characterization of CuO nanoparticles using strong base electrolyte through electrochemical discharge process

In the present study, cupric oxide (CuO) nanoparticles were synthesized by electrochemical discharge process using strong base electrolytes. The experiments were carried out separately using NaOH and KOH electrolytes. The mass output rate and the crystal size were obtained with variation of the rotation speed of magnetic stirrer for both types of electrolytes. The mass output rate of CuO nanoparticles increased with the increase in the speed of rotation, and, after an optimum speed, it started decreasing. However, the size of the particles reduced with the increase of the rotation speed. The crystal plane of the obtained CuO nanoparticles was similar for both the electrolytes whereas the yield of nanoparticles was higher in KOH as compared with NaOH under the same experiment conditions. In this set of experiments, the maximum output rates obtained were 21.66 mg h^?1 for NaOH and 24.66 mg h^?1 for KOH at 200 rpm for a single discharge arrangement. The average crystal size of CuO particles obtained was in the range of 13–18 nm for KOH electrolyte and 15–20 nm for NaOH electrolyte. Scanning electron microscopy images revealed that flower-like and caddice clew-shaped CuO nanocrystalline particles were synthesized by the electrochemical discharge process. Fourier transform infrared spectrum showed that the CuO nanoparticles have a pure and monolithic phase. UV–vis–NIR spectroscopy was used to monitor oxidation course of Cu → CuO and the band gap energy was measured as 2 and 2.6 eV for CuO nanoparticle synthesized in NaOH and KOH solutions, respectively.     

PRELIMINARY STUDIES ON PHYSICAL AND NUTRITIONAL QUALITIES OF SOME INDIGENOUS AND IMPORTANT RICE CULTIVARS OF NORTH‐EASTERN HILL REGION OF INDIA

ABSTRACT

The northeastern hills of India are endowed with rich source of rice germplasm, which may be safely estimated about 9,000 accessions, excluding the redundancies. Even though much of the germplasm have been collected, studies on nutritional aspects of these local cultivars are still lacking. Fifteen important indigenous rice genotypes collected from different rice growing ecosystem of this region were studied for physical and nutritional qualities. Kernel color of the genotypes varied from white to dark purple. All the genotypes except Manipuri were of bold‐grain type. Most of the genotypes studied have fat contents more than 2.0%. The protein content was found higher in Chahou angouba and Naga special. Five cultivars were identified as high‐protein cultivars of rice, with 10–12.07% protein content. Amylose content varied from 2.27 to 24.5%. Most of long‐grained genotypes recorded lesser amylose than short grained. Chahou varieties were found aromatic and glutinous, which demand higher market prices in local market.

PRACTICAL APPLICATION

The north‐eastern hills of India are endowed with rich source of rice germplasm, and much of the germplasm have been collected, but studies on basic and advanced nutritional aspects of these local cultivars are still lacking. This part of India has valuable rice genotypes of strong aroma, glutinous characters and slender grains with high amount of protein, fat and fiber. Having not known to the rest of the world and even to indigenous end users, some of such cultivars have already been lost, and some more are at the verge of extinction. Quality evaluation done in the present study provided useful information on their commercial exploitation and utilization in breeding programs of nutritional enhancement of rice to fight malnutrition among rice‐consuming population, which is largest in the world.     

Dust acoustic shock waves in magnetized dusty plasma

We have presented a theoretical study of the dust acoustic(DA) shock structures in a magnetized,electron depleted dusty plasma in the presence of two temperature superthermal ions. By deriving a Korteweg–de Vries–Burgers equation and studying its shock solution, we aim to highlight the effects of magnetic field and obliqueness on various properties of the DA shock structures in the presence of kappa-distributed two temperature ion population. The present model is motivated by the observations of Geotail spacecraft in the Earth?s magnetotail and it is seen that the different physical parameters such as superthermality of the cold and hot ions, the cold to hot ion temperature ratio, the magnetic field strength, obliqueness and the dust kinematic viscosity greatly influence the dynamics of the shock structures so formed. The results suggest that the variation of superthermalities of the cold and hot ions have contrasting effects on both positive and negative polarity shock structures.Moreover, it is noted that the presence of the ambient magnetic field affects the dispersive properties of the medium and tends to make the shock structures less wide and more abrupt. The findings of present investigation may be useful in understanding the dynamics of shock waves in dusty plasma environments containing two temperature ions where the electrons are significantly depleted.     

DYNAMIC VISCOELASTIC PROPERTIES OF PASTA AS A FUNCTION OF TEMPERATURE AND WATER CONTENT*

Pasta samples were tested in the linear viscoelasticity range using a dynamic mechanical thermal analyzer over the temperature range of 25 to 95C and the water content range of 12 to 20% (weight of water/weight of solids). To obtain wholesome pasta samples at different moisture levels, the intermittent sorption technique was used. The behavior of G′ and tanδversus temperature curves exhibited a transition, which was determined to be the glass transition by making comparisons to the literature values of glass transition for starch and semolina extrudates. At 12.5% water content, glass transition initiated at 48.7C. With increase in water content values, the initiating glass transition temperature decreased. At 19.7% water content, glass transition was observed in the temperature range of 36.9 to 57.3C. Although pasta contains about 13% protein fraction, it did not seem to affect the major part of glass transition range because the pasta proteins become mobile at temperatures greater than 80C and water content greater than 17%.     

AA5083铝合金的搅拌摩擦焊接工艺参数对搅拌头受力和热输入的影响(英文)

采用系统实验设计方法研究AA5083铝合金搅拌摩擦焊接工艺参数对搅拌头受力和热量输入的影响,得到了用来设计搅拌摩擦焊搅拌头和焊机的经验模型。当采用计算机来控制搅拌摩擦焊接时,这些模型可用来确定AA5083这类铝合金的摩擦焊接工艺参数、编制焊接程序及工艺参数控制。结果表明:影响轴向力和热量输入的重要参数是搅拌头转速、焊接速度和搅拌头轴肩直径,而影响纵向应力的重要参数是焊接速度和探头直径。     

EFFECT OF BAKING INGREDIENTS AND MIXING DURATION ON DOUGH DEVELOPMENT, GAS RELEASE AND BREAD MAKING PROPERTIES

Three trials were carried out to determine the effect of wet gluten, acetic acid, fat, sodium chloride and mixing duration on dough development, gas release and bread characteristics using regression analysis. Maximum dough height was significantly affected by acetic acid, wet gluten, mixing duration and sodium chloride whereas maximum gas formation was significantly affected by acetic acid and sodium chloride levels. The addition of fat had significant effects on bread volume. Sodium chloride affected overall acceptability followed by wet gluten, mixing duration and fat levels. Bread volume and overall acceptability decreased with an increase in mixing duration. Increased levels of sodium chloride increased bread volume and overall acceptability and decreased CO₂ production. Addition of fat at a level of more than 3% caused a decrease in acceptability. Bread volume and acceptability progressively increased with the increase in wet gluten levels.     

Synthesis,structure and low temperature study of electric transport and magnetic properties of GdSr<Subscript>2</Subscript>MnCrO<Subscript>7</Subscript>

The layered perovskite oxide, GdSr₂MnCrO₇, has been prepared by the standard ceramic method. The powder X-ray diffraction studies suggest that the phase crystallizes with tetragonal unit cell in the space group I4/mmm. The electrical transport properties show that the phase is an electrical insulator and the electrical conduction in the phase occurs by a 3D variable range hopping mechanism. The magnetic properties suggest that the ferromagnetic interactions are dominant in the high temperature region.     

Land-use survey of Idukki District

The growing population pressure and limited availability of land necessitates proper utilization of the available land through scientific land-use planning. Realizing this fact, a project using multiband aerial photography was taken up with following objectives: identification and mapping of areas under various land uses, study of geomorphology, identification of potential groundwater areas and identification of areas requiring soil conservation and reclamation measures. The major land-use classes mapped are agriculture, forest, wasteland, water bodies and public use. These are further subclassified. Some of the important observations are the reduction in the area under forest and the existence of a large area under wasteland. Geomorphological maps prepared depict slope, relief, drainage and vegetation. With the help of structural and geomorphological maps, the technique of identifying potential groundwater areas has been demonstrated. The land-use maps have a classification accuracy of 86 per cent whereas the accuracy of slopes in geomorphological maps is 72 per cent. The locational accuracy of the land features is 50-150 m on the ground. Visual interpretation of LANDSAT images led to the identification of nine land-cover classes while digital analysis enabled identification of twelve land-cover classes. Significant changes in land cover over a decade (1973-1982) have been noticed. This information has been used for preparation of a detailed land-use plan for the Idukki District.