Inactivation of Listeria monocytogenes and Escherichia coli by Ultrasonic Waves Under Pressure at Nonlethal (Manosonication) and Lethal Temperatures (Manothermosonication) in Acidic Fruit Juices

The inactivation of Listeria monocytogenes and Escherichia coli suspended in apple and orange juices by ultrasound under pressure at nonlethal (manosonication, MS) and lethal temperatures (manothermosonication, MTS) was evaluated. Significant differences were found in the MS resistance (35 °C, 110 μm, 200 kPa) of three strains of L. monocytogenes and three of E. coli in pH 3.5 buffer, L. monocytogenes STCC 5672 and E. coli O157:H7 being the most resistant strains. Regarding the interspecific differences, L. monocytogenes showed higher MS resistance than E. coli. Although the pH and treatment medium composition did not significantly change the bacterial MS resistance, the effectiveness of ultrasound increased by both raising the amplitude of ultrasonic waves and the pressure. The energy transmitted to the fruit juices by ultrasonic waves at different combinations of amplitudes (46.5, 90, 110, and 130.5 μm) and pressures (0, 100, and 200 kPa) was also studied, obtaining an exponential relationship between the D _MS values and power input: an increase of 116 W increased the inactivation rate approximately 10-fold in both juices. The MS resistance of both species decreased when heat was applied jointly with ultrasound (MTS), which was more effective in inactivating L. monocytogenes and E. coli than the sum of MS and heat acting simultaneously but independently. Therefore, MTS showed a synergistic lethal effect in acidic juices, whose magnitude was dependent on the treatment conditions.     

吐哈盆地北部山前带巴喀三维叠前地震成像处理解释技术研究及应用

吐哈盆地北部山前带巴喀地区地表条件复杂多样,地下构造复杂,导致该区原始地震资料品质较差,尤其是构造主体部位地层高陡,断裂非常发育,地震偏移成像难度极大,从而使得该区地下构造难以准确落实;同时巴喀地区储层为低孔低渗储层,地球物理响应特征不明显,缺乏有效的储层预测识别方法,以上因素制约了巴喀地区油气勘探的进程。通过研究,形成了针对巴喀地区的地震成像、构造解释及储层预测技术系列,其中的关键创新技术主要包括:起伏地表模型约束综合静校正技术、复杂地区"六分法"叠前噪声压制技术、浮动面逆时叠前深度偏移技术等。攻关与生产紧密结合,新研究成果能够更加准确地刻画巴喀地区的断裂位置及地下构造形态,整体成像效果得到改善,利用新研究成果重新梳理了构造样式,进一步认识了该区断裂特征及地层展布规律,新发现和落实了一批圈闭,在此基础上综合储层预测成果,优选了多个有利钻探目标。     

Uncertainty of shape memory alloy micro-actuator using generalized polynomial chaos method

Microsystem Technologies - In last decades, there has been an increasing interest in the use of micromachining technology. Intelligent materials such as shape memory alloy are considered for the...     

Deep channel operating characteristics of a single screw extruder: Finite element predictions and experimental results for isothermal non-Newtonian flow

Finite element solutions are presented for developed, isothermal, power-law flow in an extruder channel, based on a variational formulation in helical co-ordinates. The success of the method in handling non-Newtonian flow in a deep, highly-curved channel is tested by comparison with experimental results. Operating characteristics were determired under virtually isothermal conditions for a screw with depth to diameter ratio 0.25 pumping an aqueous glucose solution containing high molecular weight hydroxyethyl cellulose. Shear stress and first normal stress differences of this solution were determined in a rheogoniometer. It was both highly shear-thinning and elastic. Computed and experimental screw operating characteristics agree well, except near closed discharge, where effects due to viscous heating and elasticity are tentatively suggested.     

Effect of High Hydrostatic Pressure (HHP) Treatment on Physicochemical Properties of Horse Mackerel (Trachurus trachurus)

The basic objective of this study was to determine the effect of high hydrostatic pressure (HHP; 220, 250 and 330 MPa), holding time (5 and 10 min) and temperature (7, 15 and 25 °C) on some quality parameters of horse mackerel such as colour changes, thiobarbituric acid (TBA-i) and trimethylamine nitrogen (TMA-N), free amino acid content. HHP increased L ^* values of horse mackerel. The a ^* and b ^* of treated horse mackerel did not change significantly after HHP applications. After, HHP, TBA-i and TMA values of all HHP-treated horse mackerel samples remained unchanged than those of untreated samples. The results obtained from this study showed that the quality of high pressure treated horse mackerel is best preserved at 250 MPa, 7–15 °C for 5 min, 220 MPa, 15–25 °C for 5 min, 250 MPa, 15 °C for 10 min and 330 MPa, 25 °C for 10 min.     

聚合醇钻井液体系在吐哈油田的应用

吐哈油田储层孔隙度和渗透率低，极易受到污染；而大段泥页岩地层，极易发生水化分散膨胀，坍塌掉块，卡钻、井满等复杂事故，对储层造成严重损害。经室内试验，优选出了适合吐哈油田地层特性的聚合醇钻井液配方。聚合醇钻井液体系具有良好的润滑性、抑制性和防塌性以及保护油气层的能力。经神北4、红台10等探井和米48C、雁6—14C套管开窗侧钻水平井以及陵6—3C套管开窗侧钻定向井应用表明．聚合醇水基钻井液流交性好、性能稳定，有效地解决了井壁失稳问题．大大地降低了井下复杂事故发生率，提高了机械钻速，井眼规则，有效地保护了储层；聚合醇钻井液处理剂配伍性好，现场转化、维护和处理简便。满足了吐哈油田探井、大斜度定向井、水平井及开窗侧钻小眼井等特殊工艺井钻井施工的要求。     

Multiobjective backtracking search algorithm: application to FSI

Fluid-structure interaction (FSI) problems play an important role in many technical applications, for instance, wind turbines, aircraft, injection systems, or pumps. Thus, the optimization of such kind of problems is of high practical importance. Optimization algorithms aim to find the best values for a system’s parameters under various conditions. In this paper, we present a new Backtracking Search Optimization Algorithm for multiobjective optimization, named BSAMO, a new evolutionary algorithm (EA) for solving real-valued numerical optimization problems. EAs are popular stochastic search algorithms that are widely used to solve nonlinear, nondifferentiable and complex numerical optimization problems. In order to test the performance of this algorithm, a well known benchmark multiobjective problem has been chosen from the literature, and for FSI optimization, using a partitioned coupling procedure. The method has been tested through a 2D plate and a 3D wing subjected to aerodynamic loads. The obtained Pareto solutions are then presented and compared to those of the Non-dominated Sorting Genetic Algorithm-II (NSGA-II). The numerical results demonstrate the efficiency of BSAMO and also its best performance in tackling real-world multiphysics problems.

     

Effect of high pressure (HP) on the quality and shelf life of red mullet (Mullus surmelutus)

The effect of different temperature/time/pressure high hydrostatic pressure (HP) treatment on the quality and shelf life of red mullet were studied. Different high pressure treatments (at 3, 7, 15 and 25 °C, 5 to 10 min and 220, 250 and 330 MPa) were tested to establish the best processing conditions for the quality of red mullet. The effect of the process on the quality of the sample was examined by colour, Trimethylamine nitrogen (TMA-N) and Thiobarbituric acid number (TBA) analysis. Based on the results of the parameters, the best combinations of HP treatments were determined as 220 MPa/5 min/25 °C and 330 MPa/5 min/3 °C for red mullet. The effects of this combination treatment on sensory, chemical and microbiological properties of red mullet stored at 4 °C were studied. The results obtained from this study showed that the shelf life of untreated and HP treated stored at 4 °C, as determined by overall acceptability of sensory and microbiological data, are 12 days for untreated red mullet and 14 days for treated red mullet at 220 MPa for 5 min at 25 °C and 15 days for treated red mullet at 330 MPa for 5 min at 3 °C.Industrial relevanceFresh fish have short shelf life. HP treatment has shown to be an effective method to control pathogen and spoilage microorganisms in fish and fish products. However, high pressure treatment can promote colour and oxidation changes that could modify their sensory characteristics. The main objective of the first part of this study was to detect the best combination among the applied pressure (220, 250 and 330 MPa), temperature (3, 7, 15 and 25 °C) and time (5 and 10 min) combinations. The treatment ranges were chosen according to the unchanging colour, lower TBA value and TMA stability by HP and considering the economical aspects of HP processing. In the second part of the study, HP was applied on the selected samples and a shelf-life study was performed by measuring the changes in the quality parameters, of the samples throughout their storage. The storage conditions were set so as to achieve refrigeration handling (4 °C). Shelf-life estimation was performed according to the data obtained. HP (at 220 MPa for 5 min at 25 °C and at 330 MPa for 5 min at 3 °C) treatment is the most effective treatment for shelf-life extension as compared to non-treated red mullet.