Internet programs for drawing moth pheromone analogs and searching literature database

An Internet web page is described for organizing and analyzing information about lepidopteran sex pheromone components. Hypertext markup language (HTML) with JavaScript program code is used to draw moth pheromone analogs by combining GIF bitmap images for viewing by web browsers such as Netscape or Microsoft Internet Explorer. Straight-chain hydrocarbons of 5–22 carbons with epoxides or unsaturated positions of E or Z geometrical configuration with several alternative functional groups can be drawn by simply checking menu bars or checkboxes representing chain length, E/Z unsaturation points, epoxide position and chirality, and optional functional groups. The functional group can be an aldehyde, alcohol, or ester of formate, acetate, propionate, or butyrate. The program is capable of drawing several million structures and naming them [e.g., (E,E)-8,10-dodecadien-1-ol and abbreviated as E8E10–12:OH]. A Java applet program run from the same page searches for the presently drawn structure in an internal database compiled from the Pherolist, and if the component is found, provides a textarea display of the families and species using the component. Links are automatically specified for drawn components if found in the Pherolist web site (maintained by H. Arn). Windowed links can also be made to two other JavaScript programs that allow searches of a web site database with over 5900 research citations on lepidopteran semiochemicals and a calculator of vapor pressures of some moth sex pheromone analogs at a specified temperature. Various evolutionary and biosynthetic aspects are discussed in regard to the diversity of moth sex pheromone components.     

Curing of bromobutyl elastomer composition using a xanthogen polysulphide accelerator for medical drug delivery device applications

Bromobutyl elastomer (BIIR) can be used for sealing medical drug delivery devices due to its high resistance to permeability by moisture and gases which are known to deteriorate the performance of pharmaceutical drugs. However, its use is restricted since the traditional accelerators used for crosslinking BIIR leave reaction residues which can leach out and contaminate drugs. An accelerator based on xanthogen polysulphide (DIXP) does not leave reaction residues as it is totally consumed during crosslinking. From these considerations DIXP was used to formulate a BIIR composition for seals in medical devices. The isothermal kinetic reaction curve for BIIR showed that the crosslinking region consists of two parts. The first part had a reaction order (n) = 1 and the second stage had a lower n = 0.6–0.7. The rate constants and the activation energies for the two stages were determined. Increasing the time and temperature variables of crosslinking increased the dynamic elastic shear modulus (G′) in BIIR according to the kinetic theory of vulcanization, however the moisture ingress showed an initial decrease followed by an inflection where increasing the variables caused increased moisture ingress. This increase is believed to be caused by the volatile gaseous byproducts produced in the crosslinking reaction of DIXP which change the microstructure of BIIR. The crosslinking conditions for minimizing moisture ingress in BIIR and achieving a high G′ were identified. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Application of a Portable Handheld Infrared Spectrometer for Quantitation of <Emphasis Type="Italic">trans</Emphasis> Fat in Edible Oils

Trans fat poses serious health risks to consumers. In order to meet the FDA labeling requirements for trans fatty acids, development of fast, accurate, easy-to-use analytical methods for oils, fats and related products is desirable. Fourier transform infrared spectroscopy (FTIR) is a well-established analytical technique for quantifying trans fats, and the development of handheld FTIR units over the past decade presents new application opportunities. Our objective was to evaluate the performance of a handheld FTIR sensor for measuring trans fat content between 0.1 and 20% trans (w/w) in edible saturated and unsaturated oils. Calibration models were built by measuring height of the band at 966 cm⁻¹ and by partial least squares regression (PLSR) using benchtop FTIR as a reference method. Predictive accuracy of the models was validated with an independent test set of commercial edible oils. Calibration models developed using PLSR and linear regression of band heights gave correlation coefficients R ² > 0.98. Multivariate analysis for the handheld unit gave standard error of prediction (SEP) of approximately 1%, comparable to values obtained with benchtop systems. This study demonstrates that handheld FTIR spectroscopy coupled with chemometrics is a suitable method for quantitation of trans fat content.     

One-Dimensional Nanostructures and Devices of II–V Group Semiconductors

The II–V group semiconductors, with narrow band gaps, are important materials with many applications in infrared detectors, lasers, solar cells, ultrasonic multipliers, and Hall generators. Since the first report on trumpet-like Zn₃P₂ nanowires, one-dimensional (1-D) nanostructures of II–V group semiconductors have attracted great research attention recently because these special 1-D nanostructures may find applications in fabricating new electronic and optoelectronic nanoscale devices. This article covers the 1-D II–V semiconducting nanostructures that have been synthesized till now, focusing on nanotubes, nanowires, nanobelts, and special nanostructures like heterostructured nanowires. Novel electronic and optoelectronic devices built on 1-D II–V semiconducting nanostructures will also be discussed, which include metal–insulator-semiconductor field-effect transistors, metal-semiconductor field-effect transistors, and p–n heterojunction photodiode. We intent to provide the readers a brief account of these exciting research activities.     

Growth of c‐Axis‐Oriented BiCuSeO Thin Films Directly on Si Wafers

Single‐phase, c‐axis‐oriented BiCuSeO thin films have been directly grown on the commercial silicon (001) wafers without any surface pretreatment by using pulsed laser deposition. X‐ray diffraction pole figure confirms that the film does not have any ab‐plane texture, whereas cross‐sectional transmission electron microscopy shows good crystallinity of the film even if there exists an amorphous native oxide layer on the wafers surface. At room temperature, the resistivity of the film is about 14 mΩ cm, which is much lower than that reported for corresponding single crystals as well as polycrystalline bulks. This work demonstrates the possibility of using the available state‐of‐the‐art silicon processing techniques to create BiCuSeO‐based thin‐film thermoelectric devices.     

Determination of initiation value of mode I interlaminar fracture toughness of unidirectional polymer composites

The use of interlaminar fracture tests to measure the delamination resistance of unidirectional composite laminates is now widespread. However, because of the frequent occurrence of fiber bridging and multiple cracking during the tests, it leads to artificially high values of delamination resistance, which will not represent the behavior of the laminates. Initiation fracture from the crack starter, on the other hand, does not involve bridging, and should be more representative of the delamination resistance of the composite laminates. Since there is some uncertainty involved in determining the initiation value of delamination resistance in mode I tests in the literature, a power law of the form G_IC= A · Δ a^b (where G_IC is mode I interlaminar fracture toughness and Δ a is delamination growth) is presented in this paper to determine initiation value of mode I interlaminar fracture toughness. It is found that initiation values of the mode I interlaminar fracture toughness. G_ICini, can be defined as the G_IC value at which 1 mm of delamination from the crack starter has occurred. Examples of initiation values determined by this method are given for both carbon fiber reinforced thermoplastic and thermosetting polymers.     

Java Applet在化学热力学教学中的应用

化学热力学是物理化学的开篇内容和难点部分,学生在学习该部分内容的过程中,对热力学的一些基本概念如焓(H)、熵(S)以及它们的使用经常难以理解和想象。教学实践表明:利用Java小程序对热力学的一些概念和过程进行模拟或计算,可以将抽象的事物形象化,通过类似于"实验"的一些操作弥补单纯理论教学的不足,为热力学状态和相应热力学函数之间的关系提供一些实例。本文以理想气体状态变化、卡诺循环、盖斯定律、Gibbs自由能等四个例子来说明Java小程序在化学热力学教学中的应用。课堂教学过程中引入Java小程序,能提高学生的学习兴趣,深化对一些概念的理解,取得良好的教学效果。     

Dose estimation methodology for the UV inactivation of bioaerosols in a Continuous-Flow reactor

Indoor air microbial pollution may be responsible for various human allergies and diseases. To reduce exposure, airborne bacteria can be directly controlled through devices that employ ultraviolet-C (UV-C) radiation. In this study, a continuous annular photo-reactor was used to evaluate the inactivation dose for two species: Gram-negative Escherichia coli and Pseudomonas aeruginosa. In order to provide meaningful results, a comprehensive kinetic modeling was performed, which included the evaluation of optical properties of the microorganisms and the calculation of radiation field inside the reactor. In this way, intrinsic inactivation rates could be obtained. From the reactor modeling and the experimental data sets, the first order inactivation rate or UV susceptibility for E. coli was 0.1055?m² J^?1, while for P. aeruginosa the obtained value was 0.2579?m² J^?1. The approach used allows a straightforward scaling-up of the process for real applications and microorganism species involved.

Copyright © 2018 American Association for Aerosol Research     

Judd's 1951 color-mixture diagram

Vos demonstrated that the Judd 1951 color-mixture diagram is a projective transformation of the CIE 1931 mixture diagram. He has provided transformation formulas for computing values of x′ and y′ from x and y, but he does not explain how the one set of data is derived from the other. Neither does Judd. Judd wanted the CIE to replace the 1931 V(Λ) curve with a new V(Λ) curve and to replace the 1931 XYZ diagram with a new X′Y′Z′ diagram. I have assumed that Judd started with the CIE 1931 RGB diagram. His X′Y′Z′ diagram can be derived from the RGB diagram if we use a different set of luminosity coefficients than those specified by the CIE. This change in luminosity coefficients was no doubt intended to compensate for the use of a new V(Λ) curve, but Judd has ignored the effect that this change in the luminosity coefficients should have on the alychne of the RGB diagram and the locus of spectral colors. This makes Judd's X′Y′Z′ diagram inappropriate for use in colorimetry and for use in building color-vision models. I have proposed a new solution to this problem.     

Application of a Handheld Portable Mid-Infrared Sensor for Monitoring Oil Oxidative Stability

This study evaluated the capabilities of a handheld mid-infrared (MIR) spectrometer combined with multivariate analysis to characterize oils, monitor chemical processes occurring during oxidation, and to determine fatty acid composition. Vegetable oils (corn, peanut, sunflower, safflower, cottonseed, and canola) were stored at 65 °C for 30 days to accelerate oxidation reactions. Aliquots were drawn at 5 day intervals and analyzed by benchtop and portable handheld mid-infrared devices (4,000–700 cm⁻¹) and reference methods (IUPAC 2301 [1], 2302 [1]; AOCS Cd 8-58 [2]; and Shipe 1979 [3]). PLSR and soft independent modeling of class analogy (SIMCA) models were developed for oil classification and estimation of oil stability parameters. Models developed from MIR spectra obtained with a benchtop spectrometer equipped with a 3-bounce ATR device resulted in superior discriminative performances for classifying oils as compared to those obtained from handheld spectra (single-bounce ATR). Models developed from reference tests and handheld spectra showed prediction errors (SECV) of 1 meq/kg for peroxide value, 0.09% for acid value and 2% for determination of unsaturated fatty acids in different oils. Spectral regions ~3,012–2,850 cm⁻¹ (C–H stretching bands/shoulders of fatty acids), ~1,740 cm⁻¹ (C=O stretching of esters), and ~1,114 cm⁻¹ (–C–O stretching) were found to be important for prediction. Handheld-FTIR instruments combined with multivariate-analysis showed promise for determination of oil quality parameters. Portability and ease-of-use makes the handheld device a great alternative to traditional methods.     

GaInNAs-based Hellish-vertical cavity semiconductor optical amplifier for 1.3 μm operation

Hot electron light emission and lasing in semiconductor heterostructure (Hellish) devices are surface emitters the operation of which is based on the longitudinal injection of electrons and holes in the active region. These devices can be designed to be used as vertical cavity surface emitting laser or, as in this study, as a vertical cavity semiconductor optical amplifier (VCSOA). This study investigates the prospects for a Hellish VCSOA based on GaInNAs/GaAs material for operation in the 1.3-μm wavelength range. Hellish VCSOAs have increased functionality, and use undoped distributed Bragg reflectors; and this coupled with direct injection into the active region is expected to yield improvements in the gain and bandwidth. The design of the Hellish VCSOA is based on the transfer matrix method and the optical field distribution within the structure, where the determination of the position of quantum wells is crucial. A full assessment of Hellish VCSOAs has been performed in a device with eleven layers of Ga_0.35In_0.65N_0.02As_0.08/GaAs quantum wells (QWs) in the active region. It was characterised through I-V, L-V and by spectral photoluminescence, electroluminescence and electro-photoluminescence as a function of temperature and applied bias. Cavity resonance and gain peak curves have been calculated at different temperatures. Good agreement between experimental and theoretical results has been obtained.     

Up-conversion phosphor plate for white lighting device using NIR excitation source

Upconversion phosphors have numerous advantages compared to down conversion phosphor materials, such as a weak background interface, low excitation energy, sharp emission lines, and long lifetimes. Conventionally, blue laser diodes are used to obtain strong white light by combining green- and red-emitting phosphors. The blue-excited white-light-emitting devices can be harmful when the blue light penetrates directly into the human body. However, lower energy excited lighting devices does not harm the human body because of their low-energy photons are compatible with the biologically safe window. Hence, we present a prototype device that converts invisible near-infrared light into visible white light. For this, we synthesized orange-emitting Y₂O₃:Er³⁺, Yb³⁺ and blue-emitting Y₂O₃:Tm³⁺, Yb³⁺ upconversion phosphors using a solid-state reaction. Using these, phosphor-in-glass (PiG) samples with sintered glass frit were prepared to investigate their optical behavior under low-excitation energy. The emission color from the stacked PiGs depends on the color balance between the activator ions of Er³⁺, Tm³⁺, and Yb³⁺, and their balance is optimized to obtain a white light. The results might pave the way for designing safe white-light-emitting devices using a low-energy excitation source.     

Combining Upscaling and Downscaling of Methane Emissions from Rice Fields: Methodologies and Preliminary Results

The uncertainty in the methane (CH₄) source strength of rice fields is among the highest of all sources in the global CH₄ budget. Methods to estimate the source strength of rice fields can be divided into two scaling categories: bottom-up (upscaling) and top-down (downscaling). A brief review of upscaling and downscaling methodologies is presented. The combination of upscaling and downscaling methodologies is proposed as a potential method to reduce the uncertainty in the regional CH₄ source strength of rice fields. Some preliminary results based on upscaling and downscaling are presented and the limitations of the approaches are discussed. The first case study focuses on upscaling by using a field-scale model in combination with spatial databases to calculate CH₄ emissions for the island of Java. The reliability of upscaling results is limited by the uncertainty in model input parameters such as soil properties and organic carbon management. Because controlling variables such as harvested rice area may change on relatively short time scales, a land use change model (CLUE) was used to quantify the potential land use changes on Java in the period 1994–2010. The predicted changes were evaluated using the CH₄ emission model. Temporal scaling by coupling land use change models and emission models is necessary to answer policy-related questions on future greenhouse gas emissions. In a downscaling case study, we investigate if inverse modeling can constrain the emissions from rice fields by testing a standard CH₄ from rice scenario and a low CH₄ from rice scenario (80 and 30 Tg CH₄ yr^–1, respectively). The results of this study are not yet conclusive; to obtain fine-resolution CH₄ emission estimates over the Southeast Asian continent, the monitoring network atmospheric mixturing ratios need to be extended and located closer to the continental sources.     

Continuous Dialysis of Protein Solutions on a Large Scale. I. The Influence of Various Factors on the Efficiency of Dialysis

Abstract

Artificial kidneys have been found useful for dialysis of protein solutions in biochemical preparative work. Manufacturer's data for their use in clinics as artificial kidneys could not be adopted directly in the new application. Therefore investigations on the influence of various flow rates on the efficiency of dialysis have been made. In most investigations 1 M salt solutions have been dialyzed against deionized water, and the results are illustrated in three diagrams. A 1 M salt solution with a flow rate of 25 ml/min can be reduced to 0.1 M, which means that this procedure should be of potential value in preparative work for desalting proteins.     

Monitoring Charge Exchange in P3HT-Nanotube Composites Using Optical and Electrical Characterisation

Charge exchange at the bulk heterojunctions of composites made by mixing single wall nanotubes (SWNTs) and polymers show potential for use in optoelectronic devices such as solar cells and optical sensors. The density/total area of these heterojunctions is expected to increase with increasing SWNT concentration but the efficiency of solar cell peaks at low SWNT concentrations. Most researchers use current–voltage measurements to determine the evolution of the SWNT percolation network and optical absorption measurements to monitor the spectral response of the composites. However, these methods do not provide a detailed account of carrier transport at the concentrations of interest; i.e., near or below the percolation threshold. In this article, we show that capacitance–voltage (C–V) response of (metal)-(oxide)-(semiconducting composite) devices can be used to fill this gap in studying bulk heterojunctions. In an approach where we combine optical absorption methods with C–V measurements we can acquire a unified optoelectronic response from P3HT-SWNT composites. This methodology can become an important tool for optoelectronic device optimization.     

Polyelectrolyte‐aided synthesis of gold and platinum nanoparticles: Implications in electrocatalysis and sensing

An electrochemical method for depositing redispersible, lower size gold nanoparticles from a novel polyelectrolyte‐gold complex is described. The size of gold nanoparticles is in the range 6.2–15.4 nm. The gold nanoparticles, first deposited on platinum surface are transferable into water. They can also be directly in situ‐electrodeposited on to materials like carbon, carbon nanotubes or conducting polymers for an end use as electro catalysts. The composites Au‐MWCNT, Pt‐MWCNT, Au‐Carbon, and Pt‐Carbon are synthesized and tested for their electrocatalytic activity. The composites exhibit good catalytic activity in sensing dopamine or electrooxidation of methanol. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Polymeric materials for long‐term durability of photovoltaic systems

Photovoltaic (PV) technology has evolved rapidly in the past few decades and now encompasses a large variety of materials and device structures. A key aspect to be taken into account in any PV technology is the operational durability of the systems in outdoor conditions. Clearly, loss of performance during operation represents a significant drawback and limitation in the commercialization of this technology. In this context, the large compositional flexibility of polymeric materials as well as their proven easy processability may be of great help in imparting improved durability to PV systems. In this review, a summary on the state of the art and most recent developments in the field of polymeric materials for improved long‐term durability of PV devices is presented, with particular emphasis on the use of polymers as encapsulation materials and protective coatings in the field of both PV and light‐concentration systems. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43080.     

Conditioning polytetrafluoroethylene surfaces for use in vascular prostheses

Polytetrafluoroethylene surfaces have been treated to reduce thrombogenicity in order to make them suitable for use in prosthetic devices that come in contact with blood. This was done by first etching the surface with potassium in liquid ammonia to produce double bonds and then using these double bonds as sites for grafting on polyacids or as sites for chemical reactions. Tubes so treated were tested for thrombo-genetic activity by implantation in the thoracic aorta or inferior vena cava of dogs. These tests showed that the thrombogenicity of a polytetrafluoroethylene surface can be reduced by attaching negatively charged groups provided the surface concentration of these groups is not too high (order of 1–2 × 10^?6 equivalent per cm² geometric area) and provided the distribution of these groups is uniform. Sulfonic acid groups obtained by chlorosulfonation and carboxyl groups attached by grafting tert-butyl crotonate and hydrolyzing to crotonic acid were effective. Long chains of poly(acrylic acid), poly-(ethylenesulfonic acid), and poly(vinyl alcohol) sulfate were less effective.     

Biocatalyic synthesis of unusually photoluminescent oligomers and electrically conducting polymers of 4‐(3‐pyrrolyl)butyric acid

Unusually photoluminescent undoped oligomers and doped electrically conducting polymers of 4‐(3‐Pyrrolyl)butyric acid have been enzymatically synthesized using the oxidoreductase soybean peroxidase as a catalyst. This biocatalytic approach provides a direct route to a fluorescent‐undoped oligomer of pyrrole that requires no protection/deprotection chemistry. The synthesis is carried out in aqueous media that requires only monomer, enzyme, and hydrogen peroxide. The undoped oligomer exhibits stable emission properties and is highly sensitive to the presence of environmentally important metal ions, such as Co(II), Hg(II), and Cu(II) in solution. Electrically conducting polymers can also be obtained by adding a dopant to a buffered reaction solution prior to initiating the polymerization. Polymers doped with camphor‐10‐sulfonic acid exhibit conductivity values as high as 10^?2 S/cm. Additionally, polymers synthesized in the presence of a biobased cationic template, N,N,N‐trimethylchitosan chloride, exhibit conductivity values that are an order of magnitude greater than polymers synthesized with the anionic polymeric template, poly(styrene sulfonic acid)‐sodium salt. The biobased synthetic strategy described here is the first report of directly obtaining an undoped, fluorescent conjugated oligomer of a pyrrole in aqueous solution. Unlike conventional chemical catalysts, the enzyme does not dope the oligomer and therefore provides the opportunity to directly obtain fluorescent conjugated species. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41035.