Method and means for generation of tunable laser sidebands in the far-infrared region

A method for generating tunable far-infrared radiation is described. The apparatus includes a Schottky-barrier diode which has one side coupled through a conductor to a waveguide that carries a tunable microwave frequency; the diode has an opposite side which is coupled through a radiating whisker to a bias source. Infrared light is directed at the diode, and infrared light with tunable sidebands is radiated by the whisker through an open space to a reflector. The original infrared is separated from a tunable infrared sideband by a polarizing Michelson interferometer

Performance of multiplexed Ge:Ga detector arrays in the far infrared

The performance of two multi-element, multiplexed Ge:Ga linear arrays under low-background conditions was investigated. The on-focal switching is accomplished by MOSFET switches, and the integrated charge is made available through MOSFET source followers. The tests were conducted at 106 microns, and the radiation on the detectors was confined to a spectral window 1.25 microns wide using a stack of cold filters. At 4.2 K, the highest responsivity was 584 A/W, the noise equivalent power was 1.0 x 10(exp -16) W/square root of Hz, and the read noise was 6100 electrons/sample. A detailed description of the test setup and procedure is presented

Pineapples internal quality inspection approaches and its potential effects in Malaysia

Pineapple (Ananas Comosus L. Metil) is a tropical plant under Bromeliaceous family that is grown in American tropics, subtropics, and warmer regions (U. Nations 2012). Pineapple is the second harvest tropical fruit after banana in the world (S. Ndungu 2014). Pineapple has spiny skin that will turn into yellowish brown from green when ripe. Pineapple is a non-climatic fruit that will stop ripping once it is harvested. Pineapple is famous not only because its taste but also its nutrients for health (M. Farid Hossain 2015, p.84). It contains nutriet that can supply suffiecient requirement of calcium, sodium, potassium, fibre, vitamin C, and so on. Those nutrients can help to build up healthy and growth of bone, enhance body immune system, and decrease high blood pressure for body system

Genetic Studies of Stevioside Content and Other Agronomic Characters and Their Responses to Cloning in Stevia Rebaudiana Bert.

Stevia rebaudiana Bert. produce s the sweetener stevioside, which is 300 times sweeter than cane sugar. However, the Mean stevioside content of commercial cultivars was gene rally low and among the better cultivars the average stevioside content was in the region of seven percent. Studies were set up to investigate the genetic system temofstevio side content and other traits, the effects of cloning and the relationship of stevioside content to the other traits. Three segregating population, where up on 18 lines were selected for studying the effects of cloning

La universidad en los debates sobre departamentalización : ¿reformistas anti y pro departamentalistas? Distinciones, divergencias y particularidades del reformismo durante la politización en el campo universitario

Fil: Lázzaro Jam, Susana Jorgelina. Consejo Nacional de Investigaciones Científicas y Técnica

Market integration of wheat in Pakistan

Understanding market integration in developing countries is an important issue in current research. This study is an attempt to analyze wheat market integration in Pakistan. Previous research on the subject has attempted at analyzing market integration in Pakistan's south and north Punjab regions, mainly relying on co-integration only and not considering advanced dynamic models and transaction costs to analyze the degree of integration. Therefore, this study is a first attempt to analyze the extent of market integration in the whole country using a dynamic model. Monthly wholesale price data of five regional markets from January 1988 to April 2011 are used for this study. Price series were tested for stationarity with the Augmented Dickey Fuller (ADF) test and it was found that all prices are integrated of order one, commonly written as I(1). Co-integration was also identified in all price series pairs using Johansen's co-integration test. The Vector Error Correction Model (VECM) was then applied to the data to analyze the extent of market integration. As a result, it was found that the adjustment to shocks or disequilibrium was higher for the Lahore and Rawalpindi markets as compared to the Hyderabad and Peshawar markets. It might be because of the high consumption, low production and developed infrastructure in these regions. Adjustment coefficients were significant for most of the market pairs. The Threshold Vector Error Correction Model (TVECM) with a band of non-adjustment was applied to incorporate transaction costs, without relying on observations for these costs, which were not available for the study. It was found that linear ECMs or VECMs provide misleading results as compared to TVECMs. Short-run adjustments in the TVECM model provide mixed results depending on regimes as well as markets. Strong adjustments were found in the upper regime, which shows that when price differences are above the second threshold markets tend to adjust significantly

Radiation-Induced Graft Copolymerization of Methyl Acrylate and Acrylic Acid onto Rubber Wood Fiber

Graft copolymerization of methyl acrylate and acrylic acid monomers onto rubber wood fiber (RWF) was carried out by simultaneous radiation-induced technique. The parameters affecting the grafting reaction were investigated and the optimum conditions for both monomers obtained are as follows: impregnation time, 16 hours; total dose, 30 kGy; methanol:water ratio, 3: 1 ; monomers concentration, 40 v/v% and sulphuric acid concentration, 0.1 mol/L. Fourier Transform Infrared (FTIR), Thermogravimetry Analysis (TGA), and Scanning Electron Microscope (SEM) analyses were performed to characterize graft copolymers. The structural investigation by X-ray diffraction (XRD) shows the degree of crystallinity of rubber wood fiber decreased with the incorporation of poly(methyl acrylate) and poly(acrylic acid) grafts which causes partial destruction of the inherent crystallinity in fiber. The sorption behavior of poly(acrylic acid)- grafted RWF resin toward some metal ions was investigated using a batch technique. The binding capacities ofeu, Fe, Zn, Cd and Pb ions were 0.379, 0.795, 0.189, 0.921 and 1.218 mmol/g, respectively. The sorption capacities of poly(acrylic acid)-grafted RWF resin were selectivity toward these metal ions is in the following order: Pb > Cd> Fe > Cu > Zn. Irradiated PP/poly(methyl acrylate)-grafted RWF composite has higher mechanical properties than PP/poly(methyl acrylate)-grafted RWF composite because of EB treatment of PP is a highly efficient technique of creating chemically active sites on PP matrix, which created a better coupling, and can be proved by SEM studies and TGA analysis. Generally, the addition of poly(methyl acrylate)-grafted RWF as coupling agent into the composites reduces the flexural and tensile properties, which, causes poor and incompatible dispersion, which leads to poor filler-matrix interfacial bonding. But, the addition of 1.0 wt % of P(MA)-g-RWF into the blend give an optimum value of flexural and tensile properties

Interactions of Cyclic Hydrocarbons with Biological Membranes

Many cyclic hydrocarbons, e.g. aromatics, cycloalkanes, and terpenes, are toxic to microorganisms. The primary site of the toxic action is probably the cytoplasmic membrane, but the mechanism of the toxicity is still poorly understood. The effects of cyclic hydrocarbons were studied in liposomes prepared from Escherichia coli phospholipids. The membrane-buffer partition coefficients of the cyclic hydrocarbons revealed that these lipophilic compounds preferentially reside in the membrane. The partition coefficients closely correlated with the partition coefficients of these compounds in a standard octanol-water system. The accumulation of hydro carbon molecules resulted in swelling of the membrane bilayer, as assessed by the release of fluorescence self-quenching of fluorescent fatty acid and phospholipid analogs. Parallel to the expansion of the membrane, an increase in membrane fluidity was observed. These effects on the integrity of the membrane caused an increased passive flux of protons and carboxyfluorescein. In cytochrome c oxidase containing proteoliposomes, both components of the proton motive force, the pH gradient and the electrical potential, were dissipated with increasing concentrations of cyclic hydrocarbons. The dissipating effect was primarily the result of an increased permeability of the membrane for protons (ions). At higher concentrations, cytochrome c oxidase was also inactivated. The effective concentrations of the different cyclic hydrocarbons correlated with their partition coefficients between the membrane and aqueous phase. The impairment of microbial activity by the cyclic hydrocarbons most likely results from hydrophobic interaction with the membrane, which affects the functioning of the membrane and membrane-embedded proteins