Analysis for temperature and pressure fields in process of hydrate dissociation by depressurization

An improved axisymmetric mathematic modeling is proposed for the process of hydrate dissociation by depressurization around vertical well. To reckon in the effect of latent heat of gas hydrate at the decomposition front, the energy balance equation is employed. The semi-analytic solutions for temperature and pressure fields are obtained by using Boltzmann-transformation. The location of decomposition front is determined by solving initial value problem for system of ordinary differential equations. The distributions of pressure and temperature along horizontal radiate in the reservoir are calculated. The numeric results indicate that the moving speed of decomposition front is sensitively dependent on the well pressure and the sediment permeability. Copyright (C) 2010 John Wiley & Sons, Ltd.

process trustworthiness as a capability indicator for measuring and improving software trustworthiness

Chinese Acad Sci, ISCAS Lab Internet Software Technologies

Polyelectrolyte-functionalized ionic liquid for electrochemistry in supporting electrolyte-free aqueous solutions and application in amperometric flow injection analysis

As a green process, electrochemistry in aqueous solution without a supporting electrolyte has been described based on a simple polyelectrolyte-functionalized ionic liquid (PFIL)-modified electrode. The studied PFIL material combines features of ionic liquids and traditional polyelectrolytes. The ionic liquid part provides a high ionic conductivity and affinity to many different compounds. The polyelectrolyte part has a good stability in aqueous solution and a capability of being immobilized on different substrates. The electrochemical properties of such a PFIL-modified electrode assembly in a supporting electrolyte-free solution have been investigated by using an electrically neutral electroactive species, hydroquinone ( HQ) as the model compound. The partition coefficient and diffusion coefficient of HQ in the PFIL film were calculated to be 0.346 and 4.74 X 10(-6) cm(2) s(-1), respectively. Electrochemistry in PFIL is similar to electrochemistry in a solution of traditional supporting electrolytes, except that the electrochemical reaction takes place in a thin film on the surface of the electrode. PFILs are easily immobilized on solid substrates, are inexpensive and electrochemically stable. A PFIL-modified electrode assembly is successfully used in the flow analysis of HQ by amperometric detection in solution without a supporting electrolyte.

Electrode characteristics and microstructure of AB(2)-AB(5) composite hydrogen storage alloy formed by ball-milling process

For improving the electrode characteristics of the Zr-based AB(2)-type alloy, a new kind of composite hydrogen Zr0.9Ti0.1(Ni0.50Mn0.35V0.15)(2)(represented as AB(2)) with a rare storage alloy was successfully prepared by ball-milling I earth-based AB(5)-type alloy (represented as AB(5)) which worked as a surface modifier. Effects of ball-milling on the electrode characteristics and microstructure of Zr0.9Ti0.1(Ni0.50Mn0.35V0.15)(2) alloy and mixtures of AB(2) with AB(5) alloy were investigated. After milling the mixed AB(2) and AB(5) powders (9: 1 in mass ratio) for 10min, XRD and SEM analysis showed that AB(2) and AB(5) maintained their original crystalline states, respectively, some AB(5) particles were adhered onto the surface of AB(2), and some fresh surfaces were formed. It was found that the activation cycles of AB(2)-AB(5) composite alloy was shortened from 14 to 7 and the maximum discharge capacity was increased from 330mAh . g(-1) to 347mAh . g(-1) as compared with AB(2) alloy. The discharge rate capability of AB(2) alloy was also improved by ball milling AB(2) with AB(5) alloy process. The combined effect of ball-milling and mixing with AB(5) alloy is superior to that of sole treatment. It was believed that AB(5) alloy works not only as a regular hydrogen storage alloy, but also as a surface modifier to catalyze the hydriding/ dehydriding process of AB(2) alloy.

Application of digital image analysis to the study of banded spherulite during growing and melting process

A digital image analysis(DIA) technique can be applied directly to the image obtained by polarizing microscope. The time-resolved DIA apparatus including image collecting, showing and data analysis has been home-made. As an example, it has been used to study the banded spherulite in the blends of poly(epsilon-caprolactone) (PCL) and poly(styrene-ran-acrylonitrile) (SAN).

Use of computer-assisted sperm analysis (CASA) to evaluate the quality of cryopreserved sperm in red seabream (Pagrus major)

In the present study, the quality of post-thaw sperm of red seabream Pagrus major frozen with 6-24% DMSO was investigated. The motility, average path velocity and fertilizing capacity of fresh and their corresponding post-thaw sperm were examined for evaluation of the post-thaw sperm motion characteristics and its association with fertilizing capacity. An analysis of sperm motility before and after cryopreservation has been performed using computer-assisted sperm analysis (CASA). For post-thaw sperm frozen with 12-21% DMSO, the percentages of motile sperm were not significantly (P > 0.05) changed 10 s after activation. Moreover, the main motility pattern and swimming velocity of the motile post-thaw sperm were not significantly (P > 0.05) changed and the progressive linear motion was still the dominant pattern. However, the total motility of post-thaw sperm (72.3 +/- 6.3%) 30 s after activation was (P < 0.05) lower than the corresponding fresh sperm (82.7 +/- 7.2%). Additionally, the fertilizing capacity of post-thaw sperm was investigated with a standardized sperm to egg ratio 500:1. There is a linear regression relationship between the percentage of motile post-thaw sperm and fertilizing capability. These data demonstrate that 12-21% DMSO can provide good protection to the sperm during the freezing-thawing process. (c) 2006 Elsevier B.V. All rights reserved.

Microfluidic devices for the analysis of apoptosis

Apoptosis is the outcome of a metabolic cascade that results in cell death in a controlled manner. Due to its important role in maintaining balance in organisms, in mechanisms of diseases, and tissue homeostasis, apoptosis is of great interest in the emerging fields of systems biology. Research into cell death regulation and efforts to model apoptosis processes have become powerful drivers for new technologies to acquire ever more comprehensive information from cells and cell populations. The microfluidic technology promises to integrate and miniaturize many bioanalytical processes, which offers an alternative platform for the analysis of apoptosis. This review aims to highlight the recent developments of microfluidic devices in measuring the hallmarks as well as the dynamic process of cellular apoptosis. The potential capability and an outlook of microfluidic devices for the study of apoptosis are addressed.

The effect of market and learning orientation on strategy dynamics : The contributing effect of organisational change capability

McGuinness, T. and Morgan, R. (2005). The effect of market and learning orientation on strategy dynamics: The contributing effect of organisational change capability. European Journal of Marketing. 39(11-12), pp.1306-1326 RAE2008

Hazard and early warning analysis based on domain specific modeling technologies

An aim of proactive risk management strategies is the timely identification of safety related risks. One way to achieve this is by deploying early warning systems. Early warning systems aim to provide useful information on the presence of potential threats to the system, the level of vulnerability of a system, or both of these, in a timely manner. This information can then be used to take proactive safety measures. The United Nation’s has recommended that any early warning system need to have four essential elements, which are the risk knowledge element, a monitoring and warning service, dissemination and communication and a response capability. This research deals with the risk knowledge element of an early warning system. The risk knowledge element of an early warning system contains models of possible accident scenarios. These accident scenarios are created by using hazard analysis techniques, which are categorised as traditional and contemporary. The assumption in traditional hazard analysis techniques is that accidents are occurred due to a sequence of events, whereas, the assumption of contemporary hazard analysis techniques is that safety is an emergent property of complex systems. The problem is that there is no availability of a software editor which can be used by analysts to create models of accident scenarios based on contemporary hazard analysis techniques and generate computer code that represent the models at the same time. This research aims to enhance the process of generating computer code based on graphical models that associate early warning signs and causal factors to a hazard, based on contemporary hazard analyses techniques. For this purpose, the thesis investigates the use of Domain Specific Modeling (DSM) technologies. The contributions of this thesis is the design and development of a set of three graphical Domain Specific Modeling languages (DSML)s, that when combined together, provide all of the necessary constructs that will enable safety experts and practitioners to conduct hazard and early warning analysis based on a contemporary hazard analysis approach. The languages represent those elements and relations necessary to define accident scenarios and their associated early warning signs. The three DSMLs were incorporated in to a prototype software editor that enables safety scientists and practitioners to create and edit hazard and early warning analysis models in a usable manner and as a result to generate executable code automatically. This research proves that the DSM technologies can be used to develop a set of three DSMLs which can allow user to conduct hazard and early warning analysis in more usable manner. Furthermore, the three DSMLs and their dedicated editor, which are presented in this thesis, may provide a significant enhancement to the process of creating the risk knowledge element of computer based early warning systems.

A modelling and experimental analysis of the no-flow underfill process for flip-chip assembly

In the flip-chip assembly process, no-flow underfill materials have a particular advantage over traditional underfills as the application and curing of this type of underfill can be undertaken before and during the reflow process - adding high volume throughput. Adopting a no-flow underfill process may result in underfill entrapment between solder and fluid, voiding in the underfill, a possible delamination between underfill and surrounding surfaces. The magnitude of these phenomena may adversely affect the reliability of the assembly in terms of solder joint thermal fatigue. This paper presents both an experimental and mdeling analysis investigating the reliabity of a flip-chip component and how the magnitude of underfill entrapment may affect thermal-mechanical fatigue life.

Application of simulation technologies in the analysis of granular material behaviour during transport and storage

Problems in the preservation of the quality of granular material products are complex and arise from a series of sources during transport and storage. In either designing a new plant or, more likely, analysing problems that give rise to product quality degradation in existing operations, practical measurement and simulation tools and technologies are required to support the process engineer. These technologies are required to help in both identifying the source of such problems and then designing them out. As part of a major research programme on quality in particulate manufacturing computational models have been developed for segregation in silos, degradation in pneumatic conveyors, and the development of caking during storage, which use where possible, micro-mechanical relationships to characterize the behaviour of granular materials. The objective of the work presented here is to demonstrate the use of these computational models of unit processes involved in the analysis of large-scale processes involving the handling of granular materials. This paper presents a set of simulations of a complete large-scale granular materials handling operation, involving the discharge of the materials from a silo, its transport through a dilute-phase pneumatic conveyor, and the material storage in a big bag under varying environmental temperature and humidity conditions. Conclusions are drawn on the capability of the computational models to represent key granular processes, including particle size segregation, degradation, and moisture migration caking.

Thermo-mechanical analysis of the packaging process for micro-electronic displays

Micro-electronic displays are sensitive devices and its performance is easily affected by external environmental factors. To enable the display to perform in extreme conditions, the device must be structurally strengthened, the effects of this packaging process was investigated. A thermo-mechanical finite element analysis was used to discover potential problems in the packaging process and to improve the overall design of the device. The main concern from the analysis predicted that displacement of the borosilicate glass and the Y stress of the adhesive are important. Using this information a design which reduced the variation of displacement and kept the stress to a minimum was suggested