Purification of serine protease from mango (Mangifera Indica Cv. Chokanan) peel using an alcohol/salt aqueous two phase system

An alcohol/salt-based aqueous two-phase (ATPS) system, as a novel method of purification, was employed to purify serine proteases from mango (Mangifera Indica Cv. Chokanan) peel. The effectiveness of different parameters, such as type and concentration of alcohol (1-propanol, 2-propanol, and ethanol), type of salt (sodium citrate, potassium phosphate, and ammonium sulphate), pH, and NaCl, on the purification and selective separation of serine protease was investigated. Desirable conditions of partition coefficient (K), selectivity (S), purification factor (P), and yield (Y%) of serine protease, using ATPS, were determined. The highest partition coefficient (64.5) and selectivity (343.2) for serine protease purification value were achieved in an ATPS of 16% (w/w) 2-propanaol, 19% (w/w) potassium phosphate, and 5% (w/v) NaCl at pH 7.5. It was demonstrated that serine protease could be recovered with a yield of 96.7% and a purification factor of 11.6.     

Biomonitoring of maritime pollution by heavy metals (Pb and Zn) in the coast of Jijel (Algeria)

This paper reports a study of pollution in the coastal waters of Jijel, Algeria, using algae Ulva lactuca and Corallina officinalis as bioindicators. Samples of seawater and algae were collected at four different stations from the coast of Jijel, during the period of April–June 2014. The heavy metal content (Pb and Zn) was determined in seawater and in the algae tissue by the technique of atomic absorption spectrophotometry. In seawater, the contents of heavy metals vary from 0.017 to 0.03 mg/l (Pb) and 0.235 to 0.873 mg/l. In the algae tissues, metals concentrations vary between 1.88 to 6.25 μg g^?1 dry weight (Pb), and from 92 to 178.9 μg g^?1 dry weight (Zn). These levels differ by site and species. The calculation of the bioconcentration factor (BCF) leads us to conclude that algae bioaccumulate significant levels of Pb and Zn metals in their tissues. Our results shows that the species of C. officinalis bioaccumulate the metals Pb and Zn more than U. lactuca, where, high biosorption of Zn was observed with BCF values between 203.21 and 238.40. Zn content in seawater and algae tissues appear higher than standards set by USEPA and guides values of Certified Reference Materials, but Pb levels appear lower than this standard.     

Response surface methodology applied to supercritical carbon dioxide extraction of Piper nigrum L. essential oil

This study was conducted to optimize the supercritical carbon dioxide (SC-CO₂) extraction of Piper nigrum L. essential oil using response surface methodology (RSM). In order to obtain the maximum yield of the essential oil, experiments were carried out using a three-factor central composite design (CCD) under following conditions: pressure of 15–30 MPa, temperature of 40–50 °C and dynamic extraction time of 40–80 min. A second-order polynomial regression model expressing the total extraction yield as a function of main SC-CO₂ variables was significantly (p < 0.05) fitted, with high coefficient of determination value (R² > 0.985). The results showed that the best extraction yield (2.16%) was obtained at 30 MPa, 50 °C and 80 min. Pressure showed the most significant (p < 0.05) effect on the yield variation. The chemical composition of the essential oil was determined using GC-flame ionization detection (FID) and gas chromatography–mass spectrometry (GC–MS) analysis. The main constituents (concentration > 3.0%, calculated as % peak area) in the P. nigrum L. essential oil obtained through SC-CO₂ extraction were determined to be β-caryophyllene (24.34%), limonene (15.84%), sabinene (15.04%), 3-carene (9.44%), β-pinene (9.27%) and copaene (4.52%).     

基于水敏性城市应对的乡土策略与行为研究——以雅加达甘榜为例

历史上,受殖民主义势力的影响,印度尼西亚雅加达当地的居民被迫迁居到不太理想的土地上,那里遍布河岸、洪泛区和沼泽地等各种水敏性环境。城市在聚落的四周扩张,而多变的气候使得这些聚落易受到河流、河道和海岸的威胁。虽然水敏性城市策略已经在一定程度上成功实施,例如印度尼西亚雅加达等城市就曾有过基于社区规划和防灾体系来治理环境的历史,但是想要将水敏性城市的规划原则与设计策略真正结合起来,理解当地社区对日常生活环境的适应和管理至关重要。通过将社会文化要素与城市景观空间结构相联系,试图理解印度尼西亚地方景观中社会空间的形成过程,并将居民参与河流景观改造的日常经验与其他管理行为和过程建立联系。通过将景观作为媒介来理解这些经验和观点,能够为不同群体之间的讨论提供机会,同时也是一种综合各方意见推进雅加达水敏性城市策略实施的手段。此外还揭示了城市滨河景观社会环境治理的在地经验,基于将水敏性城市设计策略与当地社区状况结合的目标,提出了一系列的建议。     

Comparison of foam core sandwich panel and through‐thickness polymer pin–reinforced foam core sandwich panel subject to indentation and flatwise compression loadings

Through‐thickness polymer pin–reinforced foam core sandwich (FCS) panels are new type of composite sandwich structure as the foam core of this structure was reinforced with cylindrical polymer pins, which also rigidly connect the face sheets. These sandwich panels are made of glass fiber–reinforced polyester face sheets and closed‐cell polyurethane foam core with cylindrical polymer pins produced during fabrication process. The indentation and compression behavior of these sandwich panels were compared with common traditional sandwich panel, and it has been found that by reinforcing the foam core with cylindrical polymer pins, the indentation strength, energy absorption, and compression strength of the sandwich panels were improved significantly. The effect of diameter of polymer pins on indentation and compression behavior of both sandwich panels was studied and results showed that the diameter of polymer pins had a large influence on the compression and indentation behavior of through‐thickness polymer pin–reinforced FCS panel, and the effect of adding polymer pins to FCS panel on indentation behavior is similar to the effect of increasing the thickness of face sheet. The effect of strain rate on indentation behavior of FCS panel and through‐thickness polymer pin–reinforced FCS panel were studied, and results showed that both types of composite sandwich panels are strain rate dependent structure as by increasing strain rate, the indentation properties and energy absorption properties of these structures are increased. POLYM. COMPOS., 37:612–619, 2016. © 2014 Society of Plastics Engineers     

A survey of the extended finite element

This article presents an overview and recent progress of the extended finite element method X-FEM in the analysis of crack growth modeling. It summarizes the important milestones achieved by the finite element community in the arena of computational fracture mechanics. The methodology of X-FEM, different from that of the classical finite element method, presents a very particular interest since it does not force the discontinuities to be in conformity with the borders. It makes possible the accurate solution of engineering problems in complex domains, which may be practically impossible to solve using the classical finite element method.     

Purification of carbon dioxide produced during the fermentative production of fodder yeast and ethyl alcohol by Saccharomyces cerevisiae

The impurities present in carbon dioxide produced during the fermentative production of fodder yeast and ethyl alcohol by Saccharomyces cerevisiae were mainly acetaldehyde and butyraldehyde. 2,4-DNP reagent was sensitive to these impurities and they were precipitated as hydrazones. The soluble volatile organic compounds were completely removed in washers (I and II). The other impurities present in carbon dioxide were removed by treating the gas with potassium permanganate and activated charcoal to obtain pure gas. The system used in the purification of carbon dioxide in the factory was efficient when washing water was sufficient (2400 litres of running water/h) and the potassium permanganate solution was changed when it was exhausted.     

Two-level QoS-aware frame-based downlink resources allocation for RT/NRT services fairness in LTE networks

In LTE, bandwidth resources allocation became a huge burden to be handled, as both of RT and NRT traffic should be processed fairly to satisfy their diverse QoS requirements. To tackle this issue in particular, in this work, we propose a fairness-based resources allocation method named Frame-based Game Theory (FGT), which can be flexibly implemented as an upper level in LTE downlink MAC layer; before the PRBs allocation function. Basically, FGT aim is to allow involved classes with different QoS requirements to fairly gain a part of the available channel resources to transmit their flows. Adhere, on every LTE-frame, a cooperative game scenario is designed. Wherein, Shapley formula is used to distribute the available amount of data within RT and NRT traffic classes. Then, conforming to these assigned resources portions to each traffic class, PRBs allocation process is triggered every TTI for the selected flows. In this work, we adopted some of the recent PRBs allocation methods as a lower level scheduler in order to illustrate a complete idea of MAC layer scheduling functions, and also to effectively evaluate FGT performance. Simulation results on various scenarios show that, fairness index for flows from different classes is increased when FGT is considered. The results also conveyed outperforming QoS indices for FGT on RT and NRT service in terms of throughput, PLR, as well as cell spectrum efficiency.     

Color constancy for visual compensation of projector displayed image

The color of a displayed image by a projector can be distorted by features of the device, the ambient light, the projection screen, and also the observer. This has raised the need to correct the image during the display to eliminate these effects and to ensure a constancy of the color appearances. In this paper, we propose models for controlling the appearance of the displayed image. We argue that depending on the target application, the computational color constancy can be specified at different steps of the formation scheme of the sensed image by a human. Based on that observation and the image formation models, we reformulate the problem of the color constancy and we show that the resulting transformations cannot be explained by von Kries theory. Two compensation algorithms are deduced. The first allows preserving the appearance of the original image, and it can be used for the constancy of the acquired image whatever the environment conditions. The second algorithm allows to simulate appearances of a sensed image in a specific conditions. It can be used for the compensation of the screen reflectance or to create special effects or the camouflage. In addition, we propose a complementary operation for the contrast compensation which is derived from the Weber’s law. Experimental results show the merits of the proposed models and algorithms.