Measurement of release rates of gossyplure from controlled release formulations by mini-airflow method

The use of the mini-airflow apparatus for the measurement of gossyplure release rates is described. The method involves the passage of air over controlled-release dispensers containing radiolabeled pheromone, through a coarse frit, and entrapment of the gossyplure on glass beads. Desorption of the beads with solvent is followed by quantification by liquid scintillation counting. The results of release rate measurements from hollow fibers, red rubber septa, and red rubber wicks are discussed.     

The importance of real-fluid behavior and nonisentropic effects in modeling decompression characteristics of pipeline fluids for application in ductile fracture propagation analysis

The importance of real-fluid behavior during the rapid decompression of dense natural gas mixtures has been investigated using existing one-dimensional models for real-fluid isentropic decompression (RID) and perfect-gas isentropic decompression (PID). The results show that the assumption of perfect-gas behavior may result in significant errors. In the case of ductile fracture propagation (DFP) analyses, the fracture-tip pressure level may be underestimated by more than 20 percent. A real-fluid nonisentropic decompression (RND) model has been developed in order to investigate the importance of nonisentropic effects in DFP problems. The results indicate that nonisentropic effects may be neglected for pipe sizes above approximately 508 mm O.D.     

A temperature-dependent model for predicting release rates of pheromone from a polyethylene tubing dispenser

A model was developed to describe release of two formulations of tetradecenyl acetates in Shin Etsu polyethylene tubing pheromone dispensers. Change in pheromone column length in the polyethylene tubing was modeled bydl/dt=l ... (a+bT)/dt (wherel is column length,t is time interval, andT is average temperature for that time interval). Regression of the natural log of relative change in liquid length against time interval and accumulated day degrees in orchards produced the coefficientsa andb. The model was validated by comparing predicted and actual liquid length remaining in field-aged dispensers, as well as measuring release rates by using gas chromatography. Mean daily orchard temperatures and measurement of column length of dispensers on a single date were used to accurately predict column length within 15%, after six months. Predictions of instantaneous release rate were also made from this model, and other possible model uses and limitations are discussed.     

Commercial hollow-fiber pheromone formulations: The degrading effect of sunlight on celcon fibers causing increased release rates of the active ingredient

The effect of weathering on the release of pheromone analogs from Celcon fibers has been studied. Results from fibers exposed in Quebec indicate that UV radiation in sunlight degrades the Celcon, causing an increase in the release of the active materials. The results are discussed in the light of large interfiber release rate variation experienced with commercial fiber formulations, and the fact that the major use areas, to date, have been Arizona and California where the effect is likely to be much more pronounced. Stability of the release device to weathering is shown to be one of the many parameters to be considered in formulation design.Contribution No. 412, Department of Biology, Laval University.     

A vapor collection and thermal desorption method to measure semiochemical release rates from controlled release formulations

Chemicals (bp 270–490 °C/1 atm) evaporated from a controlled-release formulation dispenser were carried by an airflow to a collector packed with a polymeric adsorbent. After a set time, the chemicals were recovered by thermally desorbing them onto a gas-liquid chromatograpic column. They were then separated and quantified. The apparatus is described, and the requirements for its successful use are discussed. The soundness of the thermal desorption technique was confirmed by comparison with another technique: solvent elution from the collector. The advantages of the former technique are discussed.Mention of a commercial or proprietary product in this paper does not constitute an endorsement of that product by the USDA.     

工业规模CO2管道泄放过程中的压力响应及相态变化

基于CO₂相态分别进行了气相、气液两相和超临界状态的3组工业规模CO₂管道(长256 m,内径233 mm)泄放实验,分析了CO₂管道泄放过程中的压力响应和相态转变过程。研究表明:在管道内,气相CO₂泄放开始时压力发生突降,而后压降停滞或减慢;管内相态主要为气态,但管道末端温度大幅下降使该处形成气液均相CO₂。泄放口位于气液界面之上的气液两相CO₂泄放中,减压波多次反射并导致多次压力突降和反弹;管内相态由气液分层向气液均相转变,管道顶部和底部气液均相CO₂先后向气相CO₂转变。超临界CO₂泄放中的压力突降和反弹发生在临界区域附近,且压力穿过临界压力时,压变速率会停滞或减慢;管内相态经历了超临界、气液均相和气相泄放3个过程。     

Apparatus and procedure for measuring release rates from formulations of lepidopteran semiochemicals

An apparatus was developed wherein a vacuum source was used to pull air across a controlled-release-formulation dispenser or a planchet containing a known quantity of a semiochemical and into a collector filled with a polymeric adsorbent. After a set time, the semiochemical was eluted with solvent and was quantified by gas-liquid chromatography (GLC). High percentages of known quantities of the lepidopteran semiochemicals (Z)-7-dodecen-l -ol acetate (Z7DDA), boiling point (bp) 275 ° C/1 atm, (Z)-9-tetradecen-1-ol formate (Z9TDF), bp 289 °C/1 atm, and (Z,Z)-3,13-octadecadien-1-ol acetate (ZZODDA), bp 490 °C/1 atm, were recovered. The semiochemicals did not oxidize and were recovered quantitatively from the adsorbent. The release rates of Z9TDF from a controlled-release dispenser were found to be directly proportional to the airflow rates. Release rate measurements on the Z9TDF dispensers were made for the purpose of estimating the method's precision. The method was shown to give internally consistent results by measurements on another Z9TDF formulation. The accuracy of the method is discussed.Mention of a commercial or proprietary product in this paper does not constitute an endorsement by the USDA.     

Effect of fluorinated hydrophobic monomer on the drug release behavior for the thermosensitive hydrogels

Three series of copolymeric gels based on N‐isopropylacrylamide (NIPAAm) and perfluoroalkyl methacrylate such as 2,2,3,3,4,4,5,5‐octafluoropentyl methacrylate (OFPMA), 4,4,5,5,6,7,7,7‐octafluoro‐2‐hydroxy‐6‐(trifluoromethyl)heptyl methacrylate (OFHHMA), and 3,3,4,4,5,6,6,6‐octafluoro‐5‐(trifluoromethyl)hexyl methacrylate (OFHMA), were prepared by emulsion polymerization. The effect of perfluoroalkyl methacrylate and sodium lauryl sulfate (SLS), which can act as a surfactant and a pore‐forming agent, on the equilibrium swelling ratio and mechanical properties of the present hydrogels was investigated. Results show that hydrophobic monomers made the swelling ratio of the gel decrease and the mechanical property of the gel increase; however, SLS exhibits a contrary result. In addition, the effect of perfluoroalkyl methacrylate on the drug release behavior was also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4661–4667, 2006     

Patterns of sex pheromone release from adult females,and effects of air velocity and pheromone release rates on theoretical communication distances inTrogoderma glabrutm

By means of olfactory communication models, theoretical maximum communication distances for dispensers releasing synthetic (E)-14-methyl-8-hexadecenal (trogodermal) were confirmed in windtunnel tests withTrogoderma glabrum males. Pheromone release rates ofT. glabrum females are at least 10⁴ greater during than before calling, and are gradually reduced after calling. The models predict that, even under ideal conditions, females may attract males from only several meters. The models are used to estimate active space lengths for female and synthetic pheromone sources, as a function of realistic release rates and wind velocities.Coleoptera: Dermestidae.     

Onion fly trap catch as affected by release rates ofn-dipropyl disulfide from polyethylene enclosures

n-Dipropyl disulfide loadings of at least 1 l and 10 l in polyethylene enclosures were required to effect significant trap catches of onion fly,Hylemya antiqua (Meigen), females and males, respectively. Corresponding release rates for this threshold for trap catch were ca. 100 g/hr. Catches increased with loadings up to 100 l/capsule but then plateaued. As determined gravimetrically, the release rate from enclosures containing a reservoir of chemical remained constant under isothermal conditions but increased exponentially as a function of temperature.Diptera: AnthomyiidaePaper No. 9422 of the Michigan State University Agricultural Experiment Station. Received for publication April 29, 1980.     

阿司匹林微胶囊的制备及其体外释放行为的研究

近年来,微胶囊技术在生物医药、化工、食品等行业得到了广泛应用和发展.以液中干燥法制备阿司匹林微胶囊,研究了微胶囊的形成过程、表观形貌、粒度及其体外释放行为.研究结果表明,阿司匹林微胶囊形成过程中,乙基纤维素分散成球,继而在各微球表面析出,微球越来越细密,表面空洞减小,最终形成完整的微胶囊.微胶囊表面致密、光滑,有少量细小的孔洞,多数呈球形,但粒度不均匀,有不规则杂片存在.粒度基本呈正态分布,平均粒径为1 445 nm.随着制备微胶囊过程中阿司匹林原料药加入量的增加,微胶囊成品的实际载药量增加,但其包覆率却随之减小.在体外释放初始阶段,微胶囊中阿司匹林的释放较快,继而释放速率减慢呈缓慢上升趋势.加入少量药品制备的微胶囊中阿司匹林释放速度较大.     

铁基载氧体对煤中汞释放行为的影响

采用Ontario-Hydro方法,在管式炉中考察了煤化学链燃烧/气化过程中Fe₄Al₆载氧体对煤中汞释放率、气态汞形态分布及汞在两反应器内释放行为的影响。结果表明,载氧体对煤中汞释放率具有显著的影响,在500~700℃,与无载氧体相比,化学链燃烧过程煤中汞释放率减少,化学链气化过程煤中汞释放率增大,而在900℃时,无论化学链燃烧过程还是化学链气化过程,煤中汞释放率均减小。Fe₄Al₆载氧体能够显著增加燃料反应器出口气态Hg²⁺的相对含量,其含量随温度的升高而逐渐升高。燃料反应器的温度也是影响煤中汞在两反应器中的分布以及空气反应器中不同价态汞百分含量的重要因素。此外,相同条件下不同煤种的汞释放率不同,主要与煤的组成不同有关。该研究对揭示载氧体对煤中汞迁移的影响机理以及煤化学链转化过程汞的控制提供了实验依据。     

Stress-strain behavior of a polyurea and a polyurethane from low to high strain rates

The large deformation stress-strain behavior of thermoplastic-elastomeric polyurethanes and elastomeric-thermoset polyureas is strongly dependent on strain rate. Their mechanical behavior at very high strain rates is of particular interest due to their role as a protective coating on structures to enhance structural survivability during high rate loading events. Here we report on the uniaxial compression stress-strain behavior of a representative polyurea and a representative polyurethane over a wide range in strain rates, from 0.001 s⁻¹ to 10,000 s⁻¹, successively marching through each order of magnitude in strain rate using equipment relevant for testing at each particular rate. These results are further analyzed in association with recently reported compressive data on the same materials by Yi et al. [Polymer 2006;47(1):319-29] and intermediate rate tensile data on the same polyurea by Roland et al. [Polymer 2007;48(2):574-8]. The polyurea tested is seen to undergo transition from a rubbery-regime behavior at low rates to a leathery-regime behavior at the highest rates, consistent with the earlier compression study as well as the recent tension study; the polyurethane tested is observed to undergo transition from a rubbery-regime behavior at the low rates to a glassy behavior at the highest rates. The uniaxial compression data for the polyurea are found to be fully consistent with the recently reported uniaxial tension data over the range of rates studied, demonstrating the consistency and complementary aspects of testing at high rates in both compression and tension.     

机坪输油管道冲刷腐蚀研究

研究了冲刷腐蚀过程的发生机理,分析了流体的流速、管道的结构、流体中的第二相、流体的流动状态等因素对冲刷腐蚀过程的影响。就机坪输油管道系统中常见的易腐蚀管件90°弯管和T形管的冲刷腐蚀问题展开讨论,采用ANSYS 3.0软件中Fluent模块进行数值模拟,计算在不同工况下管道冲蚀减薄规律和特点,从而解释腐蚀的破坏程度。最后考虑到管材冲刷腐蚀的减薄程度和机坪输油系统的设计使用年限,得出冲刷腐蚀对于机坪输油管道使用寿命的影响。     

在役埋地聚乙烯给水管道自然老化行为研究

研究了埋地聚乙烯(PE)给水管道在我国台州地区实际服役7～12年过程中的自然老化行为,采用红外光谱仪(FTIR)、差示扫描量热仪(DSC)、扫描电子显微镜(SEM)等分析了管材在服役过程中不饱和基团含量、断链和支化程度、羰基指数、羟基指数等微观结构的变化趋势,考察了不同服役时间管材热稳定性、分子量、氧化诱导时间(OIT...     

Heat release rates of modern residential furnishings during combustion in a room calorimeter

Results are presented from a number of fire experiments that were conducted in a room environment to study the fire characteristics of typical residential furnishings and assist in the design of a subsequent phase of a project involving fully furnished room fire experiments. The experiments were conducted in a 16‐m² test room (with dimensions 3.8 m wide × 4.2 m long × 2.4 m high), which had a 1.5 × 1.5‐m window opening. The furnishings tested included mattresses, bed clothes, bed assemblies, upholstered seating furniture, clothing arrangements, books, plastic audio/video media and storage cases, toys, shoes, and a computer workstation setup. The smoke (gaseous products of combustion) from the room was collected using a hood system in order to measure the heat release rate (HRR) and optical density of the smoke. The test room was instrumented with load cells, heat flux gauges, thermocouples and velocity probes in order to take the following measurements: mass loss, total heat flux on gauge‐installed flush with the internal surfaces (floor, walls, and ceiling), temperatures at numerous locations, and gas velocities in the window opening. Twin‐size mattresses produced peak HRRs of approximately 3800 kW, and the maximum room temperature was approximately 980°C. The HRRs of bed assemblies of various sizes and configurations ranged from 1800 kW for a twin‐size bed to 6250 kW for a bunk bed. The maximum temperature and heat flux recorded in the experiments were 1071°C and 221 kW/m², respectively. Upholstered chairs and sofas had HRRs ranging from 630 kW for an ottoman to 3360 kW for a two‐seat sofa. In tests with clothing, toys, shoes, books, a computer workstation, and CD/DVD media, the peak HRRs ranged from 440 kW for a bookcase to 2045 kW for toys. Furnishings containing a large proportion of rigid thermoplastic plastics, such as shoes and media cases, produced very dense smoke even at low HRRs. The effect of parameters such as bed clothes, mattress type, foundation type, bed assembly and chair size, material composition, and fuel package arrangement was evident in the results. Because the room dimensions and wall lining materials remained constant, temperatures were linearly proportional to the peak HRR (and exposure time) until the ventilation limit (approximately 4100 kW) was reached. Copyright © 2014 John Wiley & Sons, Ltd.     

工业规模CO2管道大孔泄漏过程中的射流膨胀及扩散规律

通过气相和超临界状态的两组工业规模CO₂管道（长258 m、内径233 mm、泄放孔径100 mm）泄放实验,分析了近场动压、可见云以及扩散区域温度和浓度变化。研究表明：在大口径气相和超临界CO₂泄放中,泄漏口处会形成高度欠膨胀射流,在射流结构中会生成大量干冰颗粒;后者形成的欠膨胀射流结构范围较大,但马赫盘的位置都在0.4 m内。可见云在快速膨胀后,在一定时间内维持在亚稳定状态,随后缓慢衰减。可见云携带干冰颗粒和水雾快速扩散,干冰颗粒在降至地面前已全部升华,未形成干冰床。气相与超临界泄放中的扩散区域温度在迅速下降后缓慢上升,且超临界泄放中温降更大;CO₂浓度均升高后缓慢下降,预测二者5%浓度在泄漏方向上的危险距离至少为30和50 m。     

Effect of microencapsulation and spray drying on oxidative stability of flaxseed oil and its release behavior under simulated gastrointestinal conditions

Flaxseed oil is one of the richest sources of omega-3 fatty acid (α-linolenic acid, ALA). It contains high amounts of polyunsaturated fatty acids, making it extremely susceptible to oxidation. In the present study, flaxseed oil was stabilized using microencapsulation followed by spray drying and studied for its oxidative stability in terms of peroxide value (PV), thiobarbituric acid, and p-anisidine value at room temperature (35 ± 1°C) and low temperature (4–7°C) storage for 6 months. Results revealed that the developed flaxseed oil powder was stable throughout the storage period and PV remained below to the maximum permissible limit (≤5 mEq/kg oil) prescribed by the Codex Alimentarius Commission. The fatty acids profile measured by gas–liquid chromatography indicated a 14.28–15.13% decrease in ALA content in flaxseed oil as a result of microencapsulation and storage at room temperature. In vitro digestion behavior of microcapsules showed 4.39 ± 0.53 to 19.87 ± 0.47% release of flaxseed oil under simulated gastric continued, whereas under gastrointestinal conditions it was 20.00 ± 3.66 to 59.99 ± 9.29%.     

Temporal patterns of sex pheromone titers and release rates inHolomelina lamae (Lepidoptera: Arctiidae)

Six hydrocarbon components (2-methylhexadecane,n-heptadecane, 2-methylheptadecane, 2-methyloctadecane,n-nonadecane, and 2-methylnonadecane) were identified in sex-pheromone gland extracts and in airborne collections ofHolomelina lamae. Low variability in the ratio of components among individuals indicates tight regulation of blend composition. Minor changes were evident in the quantity and ratio of the blend as a function of time of day. Based on gland extracts, the total quantity of the six components increased from day 1 (X = 6299 ng) to day 4 (X = 7498 ng) and subsequently decreased. No significant correlations were found between total gland contents and wet or dry weights of moths. Emission rates ofH. lamae females were determined from pheromone adsorbed onto Porapak Q. Quantities released peaked shortly after the onset of calling and decreased rapidly as calling continued. Peak release rates ranged from 13 to 350 ng/10 min, and from 37 to 835 ng/60 min. Noncalling females did not emit detectable quantities of pheromone. Based on release rates and the rate of pulsation of the abdominal tip, the average amount released per pulse is not constant. The mean ratio of components released (0.787.45 84.802.842.591.53) was not very different from the ratio of components in gland extracts of 2-day-old females (0.704.1990.12 1.651.911.42). We propose that the blend is atomized rather than volatilized from the gland, thus retaining nearly the same ratios in the female's effluvium as in her gland.     

火电厂灰水管道清洗技术的现状

分析了火电厂灰水管道结垢的原因,介绍了目前采用和研究的几种清洗技术,并对几种清洗技术进行了比较.