Growth and Solvent Effects of a Promising Nonlinear Optical Sodium Paranitrophenolate Dihydrate (NO_2-C_H_4-ONa·2H_2O) Single Crystal

Sodium paranitrophenolate dihydrate (NPNa·2H2O) is an excellent semiorganic nonlinear optical (NLO) material, crystallizes both in water and methanol with high degree of transparency. Good optical quality single crystals of dimension upto 18 mm×6 mm×3 mm are obtained by isothermal solvent evaporation technique. The solubility of the crystal in different solvents was measured gravimetrically. The single crystals of NPNa·2H2O show variation in physical properties and growth rate in different solvents. Methanol or ethanol solution yields crystals of bipyramidal shape with clear morphology. However, methanol grown crystal is exhibiting improved hardness parameters and possesses excellent thermal stability as compared to water grown crystals. The effects of solvent on hardness parameter along with thermal and optical properties of NPNa·2H2O was revealed in this paper.     

A general simulation model of batch chemical reactors for thermal control investigations

This paper describes the development of a dynamic simulation model for stirred tank batch or semi-batch chemical reactors fitted with an alternative heating-cooling system. Heat and mass balances are established for the reactor and its jacket. Since the general purpose of our research is the thermal control of these reactors, special attention is devoted to the behaviour of the heating-cooling system. In this article, we are particularly concerned with an alternative system, i.e. different fluids at a constant temperature can be alternatively delivered to the jacket. The computer simulation programme is flexible, enabling simulation of a batch or semi-batch reaction vessel, ranging from a laboratory pilot plant to a full-scale production plant. A control algorithm is included which allows reactor operation with open or closed-loop temperature control. To demonstrate the good performance of the simulation model, experimental results are presented for both a pilot plant and an industrial reactor.     

Technical note: Accelerometer-based recording of heavy breathing in lactating and dry cows as an automated measure of heat load

Monitoring thermal status using a reliable, practical method is essential for proper cattle management during periods of high heat load. Our objective was to determine whether accelerometer-based tags, which measure heavy breathing and other behaviors on a minute-by-minute basis, accurately reflect thermal status. We hypothesized that the tags would mirror core body temperature as recorded by continuous intravaginal loggers, and that response to a cooling intervention would also be captured. Data were collected during a 3-d period from 10 late dry and 20 high-producing cows at peak lactation, each fitted with an intravaginal temperature logger and tag attached to a collar. The relationship between vaginal temperature and proportion of cows recorded as breathing heavily averaged over the three 24-h periods was described separately for each group, and during a 1-h block capturing 2 intensive cooling sessions in lactating cows. Finally, the log of the odds of a cow breathing heavily in each minute relative to vaginal temperature in cows before cooling was analyzed using a linear mixed model. The proportion of cows breathing heavily in a group mirrors changes in vaginal temperature in both dry and lactating cows. In contrast to the dry cows, lactating cows suffered from excessive heat load to a much greater degree. Cooling intensively with showers and fans effectively mitigates the effects of excessive heat load, as reflected by response in vaginal temperature and proportion of cows breathing heavily. The probability of heavy breathing increases by approximately 10% for each 0.5°C rise in vaginal temperature above 39.0°C. In conclusion, accelerometer-based technology that automatically records heavy breathing provides a practical means of continuously assessing heat load status of dairy cows, whether lactating or dry, and their response to cooling intervention. This has the potential to optimize both cow and resource management during periods of high heat load.     

Synthesis, growth, structural, optical, photoconductivity and dielectric studies on potassium p-nitrophenolate dihydrate: A new semiorganic nonlinear optical material

Potassium p-nitrophenolate dihydrate, a potential semiorganic nonlinear optical material, has been synthesized and grown by slow evaporation technique at room temperature. Single crystal X-ray analysis presents an unprecedented bonding between ions in the crystal with acentric structure. In the new structural investigation, p-nitrophenolate instead of producing bond between phenolic O⁻ and K⁺, it seems to put nitro group in bonding with the metal ion. Optical absorption shows excellent transmission in the entire visible and near-infrared region. Room temperature photocurrent, transport properties are carried out in order to enhance the application for second harmonic generation and opto-electronic devices. Dielectric constant is found to be independent at higher frequencies. The crystal possesses prominent positive photoconduction in the presence of photoactive centers formed with trap energy level. The nonlinear optical activity is confirmed by Kurtz powder test.     

Perceptual organization of two-dimensional patterns.

The perceptual organization of image patterns is considered from 2 standpoints. First, a theoretical framework is presented from which computational models of perceptual organization can be constructed and tested. Second, a specific computational model for perceptual organization of line images is described. In this model, input images are first processed by a dense array of neurons that have properties consistent with recent analyses of single-neuron responses in primary visual cortex. Then, complex image structure is discovered by interleaved pattern-matching and grouping processes constrained by a generalized uniqueness principle. A series of 3-pattern grouping experiments was performed to test a restricted version of the model and to estimate critical parameters. Using the estimated parameters, an extended version of the model was tested by generating predictions for a series of "textbook" perceptual organization demonstrations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

FE Analysis of Nitinol Leaf Springs Used in a Compression Anastomosis Device

Reconstruction of the digestive system lumen patency (anastomosis creation) after its partial surgical removal is a common and crucial procedure. The conventional anastomosis methods use devices for mechanical suturing which are associated with high failure risk and can lead to major complications. The compression anastomosis as a sutureless method seems to be a promising alternative. However, attempts during the last two centuries have not been completely successful due to the complex character of the tissue-healing process. The specific mechanical behavior of Nitinol alloys was applied to the force element of the compression devices. These devices are becoming more widely adopted in surgery practice. The compression anastomosis device enables the anastomosis of colonic and intestinal tissue based on compression forces exerted by Nitinol leaf springs. By means of changing the strain distribution in the stressed leaves with varying moments of inertia, one can gain full control of the different stages in the force-deflection profile (i.e., linear elastic stage and the force plateau stage). The target of this study is the comparison of different Nitinol leaf geometries and evaluation of the finite elements analysis as a tool for preliminary design of such geometries. The results of this analysis allow us to establish regulation of the spring??s mechanical behavior, thus controlling the anastomosis creation in the compression anastomosis device.     

Reversible cation response with a protein-modified nanopipette

The calcium ion response of a quartz nanopipette was enhanced by immobilization of calmodulin to the nanopore surface. Binding to the analyte is rapidly reversible in neutral buffer and requires no change in media or conditions to regenerate the receptor. The signal remained reproducible over numerous measurements. The modified nanopipette was used to measure binding affinity to calcium ions, with a K(d) of 6.3 ± 0.8 × 10(-5) M. This affinity is in good agreement with reported values of the solution-state protein. The behavior of such reversible nanopore-based sensors can be used to study proteins in a confined environment and may lead to new devices for continuous monitoring.     

Growth and Solvent Effects of a Promising Nonlinear Optical Sodium Paranitrophenolate Dihydrate (NO2-C6H4-ONa∙2H2O) Single Crystal

Sodium paranitrophenolate dihydrate (NPNa∙2H2O) is an excellent semiorganic nonlinear optical (NLO) material, crystallizes both in water and methanol with high degree of transparency. Good optical quality single crystals of dimension upto 18 mm×6 mm×3 mm are obtained by sothermal solvent evaporation technique. The solubility of the crystal in different solvents was measured gravimetrically. The single crystals of NPNa∙2H2O show variation in physical properties and growth rate in different solvents. Methanol or ethanol solution yields crystals of bipyramidal shape with clear morphology. However, methanol grown crystal is exhibiting improved hardness parameters and possesses excellent thermal stability as compared to water grown crystals. The effects of solvent on hardness parameter along with thermal and optical properties of NPNa∙2H2O was revealed in this paper.