Square wave voltammetric determination of methiocarb insecticide based on multiwall carbon nanotube paste electrode

Cyclic voltammogram of methiocarb in 0.1 M H₂SO₄ exhibited an irreversible anodic peak at about +1285 mV versus Ag/AgCl. Electro-oxidation and determination of methiocarb in spiked soil, river water and agrochemical formulation were realized on a newly prepared carbon-nanotube paste electrode by applying square wave voltammetry (SWV). The dE _p /dpH value indicated that the oxidation mechanism involved the coupling of H⁺ with the oxidation process. The peak signals were linearly related to methiocarb concentration in the range of 1.5–59.1 mgL^?1 with a detection limit of 0.45 mgL^?1. The accuracy and selectivity of the proposed method were shown by calculating the recoveries of methiocarb from soil, river water and pesticide formulation Mesurol^®. The calculated percent recoveries for soil and river water samples spiked with 30.0 μg g^?1 and 40.0 μg mL^?1 levels were 99.3 ± 1.2 and 98.5 ± 0.3 at 95 % confidence limit, respectively.     

Preparation and characterization of polypyrrole/selenium composites

This article reports synthesis of polypyrrole (PPy) and its composites having various amounts of selenium (Se) in the presence of nitric acid in aqueous medium via chemical oxidative polymerization. Samples were spectroscopically characterized using Fourier transform infrared spectroscopy, ultraviolet‐visible spectroscopy, and atomic absorption spectroscopy. Although morphology of the samples was examined by using scanning electron microscopy (SEM), their thermal properties were studied via differential scanning calorimetry (DSC). The alternating current (ac) conductivity and dielectric properties were investigated as a function of temperature. Variation of adsorption free energy obtained from Langmuir adsorption isotherm showed that metal cations were physically adsorbed onto the polymer surface. SEM images showed that filling process significantly changes the morphology of PPy. DSC results indicated that cold crystallization temperature (T_cc) of unfilled PPy decreases with increasing filling level. Dielectric measurements showed that relaxation times for PPy and its composites have decreased linearly with increasing temperature. The conductivity of the PPy, when filled with 1 g of Se, increased ～ four times at room temperature for 1 kHz. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Separation of squalene from olive oil deodorizer distillate using short-path molecular distillation

Squalene was recovered from an olive oil deodorizer distillate (OODD) containing 40% of squalene by a two-step process. The first step was to esterify the free fatty acids (FFAs) to make them less volatile. The second step was to separate the squalene by molecular distillation. The best esterification conditions were found to be 190°C and 360 min, where FFA content of the reaction mixture was reduced from 49.3% to 7.9%, however, an inevitable squalene loss (30%) was also observed due to a discontinuous operation. The remaining squalene (28%) in the esterified mixture was then distilled using a molecular distillation unit at elevated temperatures (190–230°C) and pressures (0.05–5 mmHg). When the temperature and vacuum during distillation increased, FFA content in the distillate reduced while distillate yield and squalene purity increased. The highest distillate yield (27.7%) and squalene purity (98.1%) were obtained at the highest applied temperature (230°C) under the lowest absolute pressure (0.05 mmHg), where FFA content of distillate was measured as 1.8%. High percentage of squalene (95%–98%) could be distilled at 230°C between 0.05 and 0.5 mmHg absolute pressures. The overall squalene recovery after all treatments was calculated as 68%.     

Definitions of terms for practical superconductors 3. fabrication,stabilization and transient losses

The definitions of terms used in describing the phenomenology and measurement practices of practical superconductive materials are proposed. The definitions cover the subject categories of: 1, fundamental states and flux phenomena; 2, critical parameters; 3, fabrication, stabilization, and transient losses; and 4, Josephson phenomena. It is intended that these terms will become the basis for the development of standard measurement practices and responses are invited.     

Understanding the potential for adoption of high-iron varieties of pearl millet in Maharashtra,India: what explains their popularity?

Pearl millet is one of the most important food staples of poorer populations in the drylands of India. To better understand the potential market for high-iron, pearl millet hybrids, we explored factors associated with growing pearl millet, and those that influence whether farmers grow major (popular) hybrids, as compared with minor cultivars in the State of Maharashtra. We tested the relationships among cultivar choice, seed source, and information sources. The data confirm that pearl millet is more likely to be grown by poorer households in drier, drought-prone areas. Scheduled castes are more likely to grow popular hybrids, and less likely to grow minor cultivars, but are no less likely to acquire seed from commercial vendors than less privileged people. Farmers who ascribe more importance to consumption attributes are more likely to grow minor than popular hybrids. De facto, popular pearl millet varieties are likely to reach less privileged farmers. To attain adoption potential, popular hybrids could be targeted for iron enrichment, and commercial marketing strategies should be pursued with diversified public and private sector partnerships.     

Numerical Evaluation by Models of Load and Spark Timing Effects on the In-Cylinder Heat Transfer of a SI Engine

The aim of this study is to examine numerically the effects of spark timing and load parameters on the in-cylinder heat transfer of a SI engine by using experimental engine test data. For the investigation, a four-stroke, air-cooled, single-cylinder SI engine was tested at different spark timings and loads at a single engine speed of 2000 rpm. Woschni, Hohenberg, and Han models were employed to estimate the in-cylinder heat transfer coefficient in the case of different test conditions because of being favorable models on the SI engine operations. The evaluations show that the in-cylinder heat transfer characteristics of the air-cooled SI engine strongly depend on the load while they slightly depend on the spark timing.     

Reducing cold-start emission from internal combustion engines by means of thermal energy storage system

Increasing environmental pollutions is an important problem appearing at cold start of internal combustion engines. Developments of new devices that solve this problem are an extremely urgent need especially for cold regions. In this study, a developed experimental sample of thermal energy storage system (TESS) for pre-heating of internal combustion engines has been designed and tested. The development thermal energy storage device (TESD) works on the effect of absorption and rejection of heat during the solid–liquid phase change of heat storage material (Na₂SO₄ · 10H₂O). The TESS has been applied to a gasoline engine at 2 °C temperature and 1 atm pressure. Charging and discharging time of the TESD are about 500 and 600 s, respectively and temperature of engine is increased 17.4 °C averagely with pre-heating. Maximum thermal efficiency of the TESS system is 57.5 % after 12 h waiting duration. CO and HC emissions decrease about 64% and 15%, respectively, with effect of pre-heating engine at cold start and warming-up period.     

Physical and surface properties of polyurethane hydrogels in relation with their chemical structure

Polyethylene glycol (PEG)/castor oil (CO)‐based polyurethanes were prepared by one‐shot bulk polymerization method with the potential for biomedical applications. Hexamethylene diisocyanate and 1,4‐buthane diol were used as diisocyanate component and chain extender, respectively. Polyurethanes were prepared (1) with crosslinker and catalyst, (2) with crosslinker and without catalyst, and (3) without crosslinker and catalyst. The effects of the ratio of CO to PEG, and presence/absence of the crosslinker and catalyst on some physical and surface properties of the polyurethanes were investigated. The glass transition temperatures of prepared polyurethanes are below room temperature. The swelling ratio increased and the water contact angle decreased with increasing amount of PEG in polymer structure. The samples prepared with crosslinker and without catalyst showed the highest swelling ratio. Gas permeability of the samples was measured in a gas permeability system and surface roughness was determined by scanning electron microscope and atomic force microscope. Protein adsorption studies were performed for the samples synthesized without crosslinker and catalyst by using bovine serum albumin and bovine serum fibrinogen. Unexpected results were obtained for the samples which have low contact angles. They exhibited relatively high protein adsorption. POLYM. ENG. SCI., 54:1182–1191, 2014. © 2013 Society of Plastics Engineers     

Acceptor formation in Mg-doped,indium-rich GaxIn1?xN: evidence for p-type conductivity

We report on the Mg-doped, indium-rich Ga_xIn_1−xN (x < 30). In the undoped material, the intrinsic electron density is very high and as a result there is no detectable photoconductivity (PC) signal within the range of temperatures of 30 <T < 300 K. In the Mg-doped material however, where the conductivity is reduced, there is a strong PC spectrum with two prominent low-energy peaks at 0.65 and 1.0 eV and one broad high-energy peak at around 1.35 eV. The temperature dependence of the spectral photoconductivity under constant illumination intensity, at T > 150 K, is determined by the longitudinal-optical phonon scattering together with the thermal regeneration of non-equilibrium minority carriers from traps with an average depth of 103 ± 15 meV. This value is close to the Mg binding energy in GaInN. The complementary measurements of transient photoluminescence at liquid He temperatures give the e-A⁰ binding energy of approximately 100 meV. Furthermore, Hall measurements in the Mg-doped material also indicate an activated behaviour with an acceptor binding energy of 108 ± 20 meV.     

Investigating the effects of feeding properties on rock breakage by jaw crusher using response surface method and gene expression programming

The present study investigates the effects of feeding properties on rock comminution by a laboratory-scale jaw crusher. For this purpose, detailed crushability tests were carried out on four different rock types to assess their degree of rock crushability (DRC). Various feeding sizes (9.5 – 19 mm) and quantities (500 – 1500 g) were adopted to reveal the choke feeding intensity during crushing actions. The efficiency of feeding properties was investigated through the response surface methodology (RSM). The RSM results demonstrated that the characterized feeding size (F₈₀, mm) dominates the general size reduction, whereas the feeding quantity (m_f, g) is associated with the crushing energy consumption and product flakiness. Therefore, the choke feeding intensity has a direct relation to the m_f and F₈₀. In addition, novel gene expression programming (GEP) models were employed to generate empirical formulations to predict the DRC parameters. The established GEP models have a satisfactory estimation capability. Therefore, the DRC of the investigated rocks can be optimized through the proposed GEP models based on the coupling variables of m_f and F₈₀.