Measurement and prediction of the concentration of 1‐methylcyclopropene in treatment chambers containing different packaging materials

BACKGROUND: 1‐methylcyclopropene (1‐MCP) has been shown to suppress ethylene response and extend the post‐harvest shelf life and quality of several fruits and vegetables. In the US and Canada, the label treatment dosage for apples is 1.0 and 0.6 µL L^?1, respectively. It has been demonstrated that wood and corrugated fiberboard materials, commonly found in apple storage facilities, absorb 1‐MCP. Losses of 1‐MCP during the exposure period might compromise the effectiveness of the product. The effects of type of material (corrugated fiberboard and high density polyethylene), relative humidity (50%, 80%, and > 95%), ratios of mass of packaging material (kg) per unit volume (m³) of airspace in a treatment chamber, and initial concentration of 1‐MCP (10 and 20 µL L^?1) on the available concentration of gaseous 1‐methylcyclopropene (1‐MCP) in an enclosed chamber were studied. RESULTS: The concentration of 1‐MCP declined in the presence of the materials tested, but the rate at which 1‐MCP gas was removed from the chamber headspace differed markedly. The average percentage loss for HDPE was between 10 and 12% at all conditions tested, while for corrugated fiberboard it ranged from 12 to 94%. CONCLUSIONS: The concentration of 1‐MCP at any time, t, follows an exponential decay behavior. For corrugated boxes, the rate at which 1‐MCP is removed increased up to 10‐fold as the relative humidity increased from 50 to 80%. The 1‐MCP depletion rate doubled as the ratio of material was increased from 4 to 8 kg of corrugated fiberboard m^?3 air. An increase of initial concentration from 10 to 20 µL L^?1 reduced the rate by half. This trend was also observed for HDPE boxes. Copyright © 2009 Society of Chemical Industry     

东南亚和印度卫生用品市场增长与创新

目前,亚太地区是一次性卫生用品最大的零售市场,而东南亚和印度占其中的1/5.2019年,东南亚一次性卫生用品零售额50亿美元,印度为20亿美元.在未来5年中,东南亚和印度的卫生用品零售业务有望继续健康增长,复合年均增长率分别为8％和16％. 在东南亚,印尼和越南等市场的零售业务稳步增长,是该地区的增长引擎.同时,印度越...     

Using visualisation as a tool for model-based recognition

The aim of the work reported here is to build a useful toolset for 3D model-based vision on an SIMD parallel machine, the AMT DAP. Included in the toolset are facilities for model specification, manipulation and rendering using a ray-tracing approach as well as model recognition and validation using a geometrical-matching approach. In particular, an SIMD parallel version of a ray tracer and an SIMD parallel version of a bottom-up geometrical matcher are described. The ray tracer can render constructive solid geometry models and incorporates spatial subdivision of the scene. The matcher uses edge primitives recovered from scenes to match to model edges using local constraints and deals with spurious data using bin assignments. The overall toolset is illustrated by its use in closed-form testing and refinement, where the models, camera geometry and frame-to-frame motion in an image sequence generated by the ray tracer are known, but are checked and validated using geometrical matching, recognition and localisation.     

Verification of Contaminant Sorption by Soil–Bentonite Barrier Materials Using Scanning Electron Microscopy/Energy Dispersive X-Ray Spectrometry

The performance of a soil–bentonite barrier material as a sorbent for heavy metals was investigated in the laboratory using an influent containing 20 mg/L of Pb2+ at a pH of 5. The target parameters were the hydraulic conductivity of the soil–bentonite mix and the difference between Pb+2 concentrations in the influent and effluent. A hydraulic conductivity of 1.0×10?8?cm/s was achieved, the mixture was found to meet common regulatory specifications for hazardous waste containment. After four pore volumes of flow through specimens placed in a column, no Pb2+ was detected in the effluent. Sorption was verified through acid extraction and identification of Pb+2 on barrier sample cross sections using microanalysis of specimen slices with a scanning electron microscope and the associated energy dispersive x-ray spectrometry. Energy dispersive x-ray spectrometry spectra indicated that the Pb2+ partitioned selectively to the bentonite fraction of the mix. The results confirm the ability of this mixture of soil–bentonite to function as an effective barrier for aqueous Pb2+ solution. This method of microanalysis appears to have promise as an effective tool for assessing relative affinity of contaminants for specific mineralogical constituents of a barrier mixture and may have applications in sorption performance assessments of other multicomponent barrier systems. If each barrier material is tested separately, the effects of the texture of the mix on sorption and hydraulic characteristics of the mix cannot be effectively assessed.     

Full disclosure data on clinical psychology doctorate programs.

The purposes of this article was to examine the rates at which Council of University Directors of Clinical Psychology (CUDCP) doctoral programs provided full disclosure information on their respective Web sites. Additionally, consistency of full disclosure data was examined using internship match rates, and summary statistics are provided for a normative basis. Of 153 programs, at least some data were located for 111 programs. Large discrepancies were found when comparing internship match statistics reported by programs with match statistics listed by Association of Psychology Postdoctoral and Internship Centers (APPIC). The mean profile of a CUDCP program includes about 160 applicants per year, of which the program admits eight new graduate students. These eight new graduate students have a GRE verbal score of 590, a quantitative GRE score of 650, an undergraduate GPA of 3.63, and take 6.5 years to complete their doctoral degree (including internship). These programs reported an average match rate of 93%. Given the Committee on Accreditation's (CoA's) new mandate for reporting program disclosure variables, the article concludes with recommendations for how best to report these data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissociation between syntactic and semantic processing during idiom comprehension.

Syntactic and semantic processing of literal and idiomatic phrases were investigated with a priming procedure. In 3 experiments, participants named targets that were syntactically appropriate or inappropriate completions for semantically unrelated sentence contexts. Sentences ended with incomplete idioms (kick the…) and were biased for either a literal (ball) or an idiomatic (bucket) completion. Syntactically appropriate targets were named more quickly than inappropriate ones for both contextual biases, suggesting that syntactic analysis occurs for idioms. In a final experiment, targets were either concrete (expected) or abstract (unexpected) nouns. For literal sentences, the abstract targets were named more slowly than the concrete targets. In contrast, there was no concreteness effect for idiomatic sentences, suggesting that the literal meaning of the idiom is not processed. Overall, the results provide evidence for dissociation between syntactic and semantic processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The flammability limits of lean fuel-air mixtures: thermochemical and kinetic criteria for explosion hazards.

The present state of knowledge is reviewed concisely in terms of the experimental methods used, the effect of apparatus size, accuracy of data, methods of data presentation, and the sensitivity of the limits to initial temperature and pressure. The heat of combustion per mole of gas mixture at the lean limit is a reliable thermochemical criterion for the flammability of organic fuels with comparable reactivities. The limit calorific value for the heavy paraffins is 11.5 +/- 0.1 kcal mole -1. However, kinetic effects strongly influence this value. Highly reactive fuels (hydrogen, acetylene) require lower energy contents, whereas less reactive fuels (ammonia) require higher values. Hydrogen-starved fuels (carbon monoxide, cyanogen) show marked anomalies and are sensitive to impurities that can provide H-atom chain carriers. These kinetic effects are reflected in the experimentally measurable burning velocity of the fuel. This parameter is a key ingredient in the theory of flammable limits, which is briefly sketched. Five competing processes dissipate power from the combustion wave and quench it at some characteristic limit velocity. The prevalent consensus that the limits are controlled by natural convection is clearly demonstrated, and the complex interplay of kinetics and thermochemistry follows logically therefrom.     

Electrochemical nucleic acid-based sensors for detection of Escherichia coli and Shiga toxin-producing E. coli—Review of the recent developments

Escherichia coli are a group of bacteria that are a natural part of the intestinal flora of warm-blooded animals, including humans. Most E. coli are nonpathogenic and essential for the normal function of a healthy intestine. However, certain types, such as Shiga toxin-producing E. coli (STEC), which is a foodborne pathogen, can cause a life-threatening illness. The development of point-of-care devices for the rapid detection of E. coli is of significant interest with regard to ensuring food safety. The most suitable way to distinguish between generic E. coli and STEC is by using nucleic acid-based detection, focusing on the virulence factors. Electrochemical sensors based on nucleic acid recognition have attracted much attention in recent years for use in pathogenic bacteria detection. This review has summarized nucleic acid-based sensors for the detection of generic E. coli and STEC since 2015. First, the sequences of the genes used as recognition probes are discussed and compared to the most recent research regarding the specific detection of general E. coli and STEC. Subsequently, the collected literature regarding nucleic acid-based sensors is described and discussed. The traditional sensors were divided into four categories such as gold, indium tin oxide, carbon-based electrodes, and those using magnetic particles. Finally, we summarized the future trends in nucleic acid-based sensor development for E. coli and STEC including some examples of fully integrated devices.     

Modelling of adsorption of nickel (II) by blend hydrogels (cellulose nanocrystals and corn starch) from aqueous solution using adaptive neuro-fuzzy inference systems (ANFIS) and artificial neural networks (ANN)

The current study looks at the effectiveness of the removal of nickel (II) from aqueous solution using an adsorption method in a laboratory-size reactor. An artificial neural network (ANN) and an adaptive neuro-fuzzy inference system (ANFIS) were used in this study to predict blend hydrogels adsorption potential in the removal of nickel (II) from aqueous solution. Four operational variables, including initial Ni (II) concentration (mg/L), pH, contact duration (min), and adsorbent dose (mg/L), were used as an input with removal percentage (%) as the only output; they were studied to assess their impact on the adsorption study in the ANFIS model. In contrast, 70% of the data was used for training, while 15% of the data was used in testing and validation to build the ANN model. Feedforward propagation with the Levenberg–Marquardt algorithm was employed to train the network. The use of ANN and ANFIS models for experiments was used to optimize, construct, and develop prediction models for Ni (II) adsorption using blend hydrogels. The adsorption isotherm and kinetic models were also used to describe the process. The results show that ANN and ANFIS models are promising prediction approaches that can be applied to successfully predict metal ions adsorption. According to this finding, the root mean square errors (RMSE), absolute average relative errors (AARE), average relative errors (ARE), mean squared deviation (MSE), and R² for Ni (II) in the training dataset were 0.061, 0.078, 0.017, 0.019, and 0.986, respectively, for ANN. In the ANFIS model, the RMSE, AARE, ARE, MSE, and R² were 0.0129, 0.0119, 0.028, 0.030, and 0.995, respectively. The adsorption process was spontaneous and well explained by the Langmuir model, and chemisorption was the primary control. The morphology, functional groups, thermal characteristics, and crystallinity of blend hydrogels were all assessed.     

Selective removal of Cr (VI) from hydrometallurgical effluent using modified cellulose nanocrystals (CNCs) with succinic anhydride and ethylenediaminetetraacetic acid: Isotherm,kinetics, and thermodynamic studies

Biological sources are renewable basic resources that may be used for several purposes, including the development of green materials for the removal of heavy metal ions. Cellulose nanocrystals (CNCs) extracted from waste papers via acid hydrolysis were modified and utilized as adsorbents to remove Cr (VI) ions from metallurgical effluent in this work. X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis, and zeta potentiometer were used to characterize the CNCs. The CNCs treated with succinic anhydride and ethylenediaminetetraacetic acid tetrasodium salt have thin particle sizes and are porous. The carboxylate functional group is primarily engaged in the coordination and selective removal of metal ions (–COO²⁻) and thermal degradation of 85%, observed at temperatures between 250–380°C. On the surface of the modified CNCs, the zeta potential data showed a decrease in negative value. The results revealed that the modified CNCs had a maximum adsorption capacity of 387.25 ± 0.88 mg L⁻¹ at pH 5, at CNCs doses of 25 and 400 mg L⁻¹ as starting concentrations. The adsorption equilibrium period was 300 min and the temperature was 313 K. The equilibrium results fit the Langmuir isotherm model with an R² of 0.993 and a qmax of 340 ± 0.97. The Chi-square (X²) and Marquardt's percent standard deviation tests confirmed that the adsorption process was pseudo-second-order with an R² of 0.998, and the Elovich model revealed that Cr (VI) complexed with the adsorbent's functional groups. The reaction was endothermic due to positive ΔH and spontaneous due to negative ΔG. The positive ΔS indicates that the adsorption process enhances the unpredictability of the solid/liquid interface, according to thermodynamic analysis. After acid treatment, the CNCs may be effectively reused for six cycles with an adsorption capacity of 220 ± 0.78 mg g⁻¹.