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Abstract: A wide range of mathematical models for multiple effect evaporators in process industry including paper industry are well reported in the literature but not so extensive work on the dynamic behavior of MEE system is available in the literature. In the present study dynamic behavior of multi-effect evaporator system of a paper industry is obtained by disturbing the feed flow rate, feed concentration, live steam temperature and feed temperature. For this purpose an unsteady-state model for the multi-effect evaporator system is developed. Each effect in the process is represented by a number of variables which are related by the energy and material balance equations for the feed, product and vapor flow. A generalized mathematical model which could be applied to any number of effects and all kinds of feeding arrangements like forward feed, backward feed, mixed feed and spilt feed in the MEE system with simple modifications was finally obtained. Finally model for mixed feed sextuple effect falling film evaporators system was solved using MATLAB. For the steady state and dynamic simulation the ‘fsolve’ and ‘ode45’ solvers in MATLAB source code is used respectively. [Copyright &y& Elsevier]

Abstract: Zanotti et al. recently reported on the thermal diffusivity of NiTi shape memory alloys. In the experimental part of their work, they measured the temperature in the cylindrical sample, and they found that this temperature is significantly influenced by the latent heat. The mathematical model used for the determination of the thermal diffusivity was based on the 1D unsteady heat diffusion equation. They found a drastic decrease and then increase of the thermal diffusivity in the transformation temperature range. This negative peak, however, has no physical meaning because the general heat conduction equation was derived and solved with boundary conditions that require that no phase transformations occur in the material. The latent heat changes the temperature distribution in the sample, so selected model cannot be applied in the transient temperature range. [Copyright &y& Elsevier]

Abstract: A multivariate data analysis of cavitation indicators and parameters was carried out to improve the quantitative characterization of cavitation processes used in manufacturing and medical applications. The indicators were obtained from four model measurement methods applied to a 45kHz cleaning vessel. Together with experimental data such as temperature and electrical input power they form the data basis of a factor analysis. The loadings of three factors were calculated and the indicators, the parameters, and finally the data were depicted in factor space. The factors show relations between the variables and several overlapping indicators and parameters were identified. The coordinates of the data (data scores) indicate tendencies within the data and the assessment of the factors allows the finding of hidden relations. Using the factor analysis three representing indicators or parameters specific to the application case are identified which can be used for a complete description of the process. This characterization method can favourably be applied in quality management systems. [Copyright &y& Elsevier]

Abstract: In this paper, four sensor types are presented for quantitative measurements in an ultrasonic cleaning vessel: (1) a hydrophone to measure spectral components of the sound field; (2) an aluminium foil technique as a model process for erosion; (3) a test tube filled with a solution of luminol to measure the emission of light; and (4) a test tube filled with potassium iodide solution to measure the oxidation of iodide. Thus a broad range of diverse cavitation effects is covered. The quantities were measured in dependence on three parameters: the electrical input power of the transducers, the temperature and the O2 concentration of the water. To ensure constant environmental conditions, a flow system was built up which continuously exchanges the water in the vessel. The comparability of the data measured in subsequent measurement cycles is discussed and the influence of the different sensor types on the cavitation field is considered. Dependences on the three parameters are shown. A quantitative analysis of correlations between the data is carried out in the second part of the study (Koch and Jüschke, 2012 ). [Copyright &y& Elsevier]

The upstream offshore multi-phase well-pipeline-riser installations are facing huge challenges related to slugging flow: An unstable flow regime where the flow rates, pressures and temperatures oscillate in the multi-phase pipelines. One typical severe slug is induced by vertical wells or risers causing the pressure to build up and hence originates the oscillating pressure and flow. There exist many negative consequences related to the severe slugging flow and thus lots of investments and effort have been put into reducing or completely eliminating the severe slug. This paper reviews in details the state-of-the-art related to analysis, detection, dynamical modeling and elimination of the slug within the offshore oil & gas Exploration and Production (E&P) processes. Modeling of slugging flow has been used to investigate the slug characteristics and for design of anti-slug control as well, however most models require specific facility and operating data which, unfortunately, often is not available from most offshore installations. Anti-slug control have been investigated for several decades in oil & gas industry, but many of these existing methods suffer the consequent risk of simultaneously reducing the oil & gas production. This paper concludes that slug is a well defined phenomenon, but even though it has been investigated for several decades the current anti-slug control methods still have problems related to robustness. It is predicted that slug-induced challenges will be even more severe as a consequence of the longer vertical risers caused by deep-water E&P in the future. [ABSTRACT FROM AUTHOR]

Cave radon concentration measurements reflect the outcome of a perpetual competition which pitches flux against ventilation and radioactive decay. The mass balance equations used to model changes in radon concentration through time routinely treat flux as a constant. This mathematical simplification is acceptable as a first order approximation despite the fact that it sidesteps an intrinsic geological problem: the majority of radon entering a cavity is exhaled as a result of advection along crustal discontinuities whose motions are inhomogeneous in both time and space. In this paper the dynamic nature of flux is investigated and the results are used to predict cave radon concentration for successive iterations. The first part of our numerical modelling procedure focuses on calculating cave air flow velocity while the second part isolates flux in a mass balance equation to simulate real time dependence among the variables. It is then possible to use this information to deliver an expression for computing cave radon concentration for successive iterations. The dynamic variables in the numerical model are represented by the outer temperature, the inner temperature, and the radon concentration while the static variables are represented by the radioactive decay constant and a range of parameters related to geometry of the cavity. Input data were recorded at Driny Cave in the Little Carpathians Mountains of western Slovakia. Here the cave passages have developed along splays of the NE–SW striking Smolenice Fault and a series of transverse faults striking NW–SE. Independent experimental observations of fault slip are provided by three permanently installed mechanical extensometers. Our numerical modelling has revealed four important flux anomalies between January 2010 and August 2011. Each of these flux anomalies was preceded by conspicuous fault slip anomalies. The mathematical procedure outlined in this paper will help to improve our understanding of radon migration along crustal discontinuities and its subsequent exhalation into the atmosphere. Furthermore, as it is possible to supply the model with continuous data, future research will focus on establishing a series of underground monitoring sites with the aim of generating the first real time global radon flux maps. [ABSTRACT FROM AUTHOR]

Mathematical modelling and the dynamic simulation of battery storage systems can be challenging and demanding due to the nonlinear nature of the battery chemistry. This paper introduces a new dynamic battery model, with application to state of charge estimation, considering all possible aspects of environmental conditions and variables. The aim of this paper is to present a suitable convenient, generic dynamic representation of rechargeable battery dynamics that can be used to model any Lithium-ion rechargeable battery. The proposed representation is used to develop a dynamic model considering the thermal balance of heat generation mechanism of the battery cell and the ambient temperature effect including other variables such as storage effects, cyclic charging, battery internal resistance, state of charge etc. The results of the simulations have been used to study the characteristics of a Lithium-ion battery and the proposed battery model is shown to produce responses within 98% of known experimental measurements. [ABSTRACT FROM AUTHOR]

The weather options were created to enable companies to hedge against climate risks. However, the valuation of weather options is complex, since the underlying temperature process has no negotiable price. This paper presents a new weather option pricing model, which is governed by a stochastic underlying temperature following a mean-reverting Browning motion with jump–diffusion under the assumption of mean-self-financing. Consequently, a two-dimensional partial integro-differential equation (PIDE) is derived to value the weather-based options. The numerical techniques applied in this paper are based on a Semi-Lagrangian method (SLM), in which at each time-step a set of one dimensional partial integro-differential equations are solved and the solution of each PIDE is updated using Semi-Lagrangian time-stepping. In addition, monotonicity, stability, and the convergence results of the discrete schemes are also derived in this paper. Lastly, this paper values a series of European HDD-based weather put options using SLM, and highlights the key details of the numerical implementation. [ABSTRACT FROM AUTHOR]

The aim of the study is to develop a new method for numerical modeling of tubular cross-flow heat exchangers. Using the method proposed in the paper, a numerical model of a car radiator was developed and implemented in a digital control system of the radiator. To evaluate the accuracy of the numerical method proposed in the paper, the numerical model of the car radiator was compared with an analytic model. The proposed method based on a finite volume method and integral averaging of gas temperature across a tube row is appropriate for modeling of plate fin and tube heat exchangers, especially for exchangers in which substantial gas temperature differences in one tube row occur. The target of control is to regulate the number of fan revolutions per minute so that the water temperature at the heat exchanger outlet is equal to a set value. Two control techniques were developed. The first is based on the numerical model of the heat exchanger developed in the paper while the second is a digital proportional–integral–derivative control. The first control method is very stable. The digital proportional–integral–derivative controller becomes unstable when the water volume flow rate varies considerably. The developed techniques were implemented in digital control system of the water exit temperature in a plate fin and tube heat exchanger. The measured exit temperature of the water was very close to the set value of the temperature if the first method was used. The experiments show that the proportional–integral–derivative controller works also well but becomes frequently unstable if the water flow rate varies. [ABSTRACT FROM AUTHOR]

This paper discusses the effect of temperature polarization in Vacuum Membrane Distillation (VMD). The main motivation for using VMD in this work is that this module configuration is much simpler and more suitable for this kind of investigation than the other MD configurations such as Direct Contact Membrane Distillation (DCMD). The coupling between heat and mass transfer mechanisms at the feed-membrane interface is presented from a theoretical point of view. In addition, a new simple graphical method and a mathematical model for determining VMD flux are presented. The two methods used in evaluating the extent of temperature polarization effect on water vapor flux (flux sensitivity factors and temperature polarization coefficient (TPC)) are also analyzed and compared. The effect of integrating a heat recovery system in a large scale module on the TPC coefficient has also been studied and presented in this paper. [ABSTRACT FROM AUTHOR]

Power consumption in the field of evaporation and crystallization has attracted extensive attentions all over the world. In this paper, humidification and cooling crystallization methods are involved simultaneously to constitute a novel evaporation and crystallization configuration. In light of the thermal processes included, mathematical models based on the mass and energy equilibrium are established. The characteristics of the adopted evaporation and crystallization system (ECS) at the designed parameters are first simulated and analyzed, and the corresponding influence laws from the appointed key parameters are analyzed. Furthermore, a scale and economic analysis is also achieved to explore the application prospect of the evaporation crystallization system. The practicability of the novel evaporation and crystallization system at ambient temperature is verified, with a descent amplitude of 52.88% for the energy consumption of evaporated water within the prescribed range of the air mass flow rate. The simulation results indicate variation of the inlet air parameters, including the relative humidity and temperature, is not effective to improve the thermal efficiency of the evaporation and crystallization system, while an evident reduction for the energy consumption of evaporated water (ECEW) as 45.08 kWht −1 is achieved in response to the volume growth of the packings from 15 m 3 to 30 m 3 . Finally, it is also found that the cost of heat and mass transfer areas will rise significantly with the increase of the volume although the energy conversion is improved. [ABSTRACT FROM AUTHOR]

Crop modelling has become an effective means to assess climate change impact on crop yield and to assist in development of adaptation strategies. Previous studies found large uncertainty in simulated crop yields, especially beyond optimal temperature range. In this paper, we combined the data reported in literature and our controlled-temperature experiment to derive the temperature response functions of phenological development and biomass growth of maize crop based on the Wang-Engel function (Agricultural systems, 58(1): 1–24), and compared them with those adopted in two mostly used maize growth models APSIM-Maize and CERES-Maize. Our results support the previous findings that leaf elongation, leaf appearance and the rate of development towards flowering have the same temperature response. Our results indicate that a curvilinear response with cardinal temperatures of 5 °C (base), 30 °C (optimum), and 41 °C (maximum) best describes the maize developmental response to temperature. For radiation use efficiency (RUE-biomass growth per unit intercepted radiation) of maize, the corresponding cardinal temperatures are likely to be 2 °C, 24 °C, and 38 °C respectively. All the cardinal temperatures are lower than what are used in current APSIM model. Replacing the default temperature responses with the newly derived ones led to contrasting differences in simulated flowering and maturity time across China’s Maize Belt, while the differences in simulated maize yield were relatively smaller. This implies the importance to use the correct temperature response in maize growth modelling so that the genotype by environment interactions in response to rising temperature can be correctly captured. [ABSTRACT FROM AUTHOR]

The heterogeneous nucleation process is important for the study of the nucleate boiling of the mixed refrigerants. In this paper, the onset of heterogeneous bubble nucleation of non-azeotropic mixtures was analysed based on the change in the Gibbs free energy. From the calculated results, the critical radius, change in availability, onset of boiling (ONB) superheat and heat flux were determined. The results showed that the critical radius and the maximum change in the availability of the mixtures was higher than that of the corresponding pure fluids. The ONB superheat first increased and then decreased when the mole fraction of the high boiling point component was increased. In addition, experimental tests were conducted to measure the ONB temperature and heat flux of R124, R22 and R124/R22 mixtures on a copper surface at the pressure of 0.7–0.85 MPa. The ONB superheat and heat flux first increased and then decreased when the concentration of R124 was increased. Additionally, the experimental ONB superheat and heat flux were used to validate the correlations of other models as well as the model presented here. Our model shows much better agreement with the experimental data. Most of the experimental results had an error of +20% to −40%. [ABSTRACT FROM AUTHOR]

Abstract: This paper proposes a new frequency domain method to model the heat transfer between the injected/extracted heat and the temperature of the fluid exiting a borehole heat exchanger. The method is based on in situ measurements and focuses particularly on the short-term borehole heat transfer. It uses a rational function of the Warburg variable in the Laplace domain to model the borehole heat transfer. The rational model is transformed to a time domain model using inverse Laplace transformation. This time domain model makes it possible to calculate the temperature response on a random heat variation signal. The paper also demonstrates a new way to perform the classical thermal response test. Instead of injecting a constant amount of heat, the experiments have been performed using multiple short-duration heat injections. In this way, the obtained rational heat transfer model contains information about both the short- and the long-term heat transfer. The results obtained using the proposed modeling method are compared with those obtained from a state-of-the-art analytical method. The time domain model can be used to design a controller to optimize the performance of a Ground Source Heat Pump system, the efficiency of which depends strongly on the temperature of the fluid exiting the borehole. [Copyright &y& Elsevier]

Abstract: In this paper, a transient numerical model for a liquid-to-air membrane energy exchanger (LAMEE) is developed and the results are compared to the experimental data. The data for the sensible, latent and total effectiveness are compared with transient and steady-state simulations for various values of NTU and operating parameters (Cr∗, inlet temperature and humidity) while the exchanger undergoes a step change in inlet conditions and reaches a new steady-state. The transient and steady-state performances are shown to be a function of the design and operating parameters. The paper also shows that buoyancy forces become important and affect the LAMEE performance under certain operating conditions. The verified numerical model is used to investigate the impact of outdoor air conditions on the LAMEE performance. [Copyright &y& Elsevier]

Abstract: With the aim of dynamic simulation and control, a new non-linear state-space dynamic non-isothermal polymer electrolyte membrane fuel cell (PEMFC) model is developed in this paper. This mathematical model is developed based on mass and energy equation. The present model takes in account subsequent factors as the effects of charge double layer capacitance, the geometrical capacity and the effect of temperature gradient. In this paper, the authors propose a combination of several dynamic equations to study the effect of suddenly variation of some operating parameters like load resistance, gas pressure and gas temperature input. The results are compared to those of an isothermal model. This model will be extremely functional for the best possible design and real-time control of PEMFC systems. The present model is executed in MATHCAD software and the fuel cell is symbolized by an equivalent circuit which incorporates gas diffusion layer, membrane and electrodes. The analysis results show that the main elements that influence the performance of the cell are load resistance and functioning temperature. [Copyright &y& Elsevier]

In this paper, a novel model is presented for predicting thermophysical properties of superheated steam (SHS) in offshore superheated steam injection wells (OSSIW). Firstly, a mathematical model comprised of mass, energy and momentum balance equations is proposed for OSSIW. Secondly, the distribution of temperature, pressure and superheat degree along the wellbores are obtained by finite difference method on space and solved by using the iteration technique. Then, model validation and sensitivity analysis are conducted. The results show that (1). The superheat degree increases at first but then turns to decrease with the increase of injection rate. (3). The superheat degree increases with the increase of injection temperature. (4). The superheat degree at well bottom increases at first but then turns to decrease with the increase of injection pressure. (5). The superheat degree in the wellbore has a drop when seawater starts to flow. [ABSTRACT FROM AUTHOR]

In this paper, heat conduction and thermo-elasticity models of repetitive pulse laser irradiation are established, and analytical solutions for temperature and thermal-stress of solid material induced by repetitive pulse laser irradiation are obtained using integral transform method. Temperature and thermal-stress distributions of solid silicon material for different parameters are given. Results show that, when the silicon irradiated by a repetitive pulse laser, temperature and thermal-stress accumulation effects will occur on the surface and inside the material. Temperature and thermal-stress rise in the laser irradiating cycle time and decrease in the cooling cycle time. In the thin layer of silicon surface vicinity, temperature and thermal-stress rise due to absorption of irradiated energy dominates over the conduction energy transport from surface to vicinity. As the depth increases, the absorption decreases, whereas the conduction enhances. The results of this study can give some theoretical basis for revealing the mechanism of repetitive pulse laser irradiation and provide some guidance for experiments of repetitive pulse laser irradiation in the next work. [ABSTRACT FROM AUTHOR]

Moderate or Intense Low-oxygen Dilution (MILD) combustion which known as a combustion under highly preheated and diluted condition is a relatively new combustion regime including many differences in comparison with the traditional one. Among many distinguished disparities between combustion modeling of conventional and MILD ones, turbulent-chemistry interaction modeling is an open field of study. Current knowledge on modeling this combustion regime shows that the eddy dissipation concept (EDC) model could be successfully used for modeling of this combustion regime. In this paper, it has been tried to propose some guidelines to modify the semi-empirical constants of the original EDC model for MILD combustion. In this way a parametric study of the EDC model constants for a nonpremixed MILD burner is done in terms of accuracy of prediction while the responses of the model to its constants are focused on the basis of physical arguments. Burner of Dally et al. (JHC) is modeled using the RANS approach in a 2D axisymmetric computational domain for different oxygen levels and fuel jet Reynolds numbers when a reduced detail chemical mechanism of DRM-22 is used to represent the chemical mechanism. Moreover using a well-stirred–reactor analysis and extracting the chemical reactions pathways, discussions are completed. Results show that reducing the C D2 constant which leads to a decrease in time scale and volume fraction constants of the model would improve the performance of the model for MILD condition. Prediction of flame lift-off and minor OH species has been improved by changing default model constants of C τ and C γ to around 0.0893 and 1.0, respectively, especially for lower oxygen levels. Indeed reaction pathway analysis and dimension of reaction zone showed that reducing scales of the defined reactor in the EDC model (i.e. fine structure) to the Kolmogrov or smaller scales might push the reactions inside each structure toward the non-equilibrium condition and enlargement of overall reaction zone and make the EDC model more compatible with MILD combustion characteristics. Reduction in the length and time scales of the fine structure led to improvement in Temperature, OH, and CO profiles inside of MILD region of the JHC burner, although for CO, disagreement is still considerable. Considering error analysis of five checked parameters (i.e. H 2 O, CO 2 , OH, CO, and temperature) at both MILD and conventional regions of the JHC burner may conduct us toward that the defaults setting of the model still works reasonably on the whole when it is used at both regions. [ABSTRACT FROM AUTHOR]

In this paper, a mathematical model has been developed to calculate solar cell temperature and module efficiency in opaque mono crystalline silicon (sc-Si) PV module on the basis of degradation rate. The calculated results have been validated by experimental investigations for the opaque PV module. Module efficiency and solar cell temperature of the opaque PV module decrease with increase in degradation rate. In this context, energy matrices are developed and enviroeconomic analysis has been done on the basis of annual energy output of PV modules for different degradation rate. Efficiency and temperature of PV module have been decreasing with an increase in the degradation rate. The energy payback time is found to be 8.80 years and 9.29 years for degradation rate 0.3%/year and 0.9%/year, respectively and unit cost (Rs./kWh) increase with an increase in the degradation rate of PV module. Similarly, the environmental cost reduction is higher for 0.3%/year degradation rate and lower for 0.9%/year degradation rate. [ABSTRACT FROM AUTHOR]

Abstract: Modified Atmosphere Packaging (MAP) of fresh produce is a dynamic system and relies on the modification of the atmosphere inside the package, achieved by the natural interplay between two processes, the respiration of the product and the transfer of gases through the packaging film, which leads to an atmosphere richer in CO2 and poorer in O2. The challenge is how to integrate the mathematical modelling depicting product respiration rate and package permeability to simplify the packaging design process. The aim of this paper is to show the application of integrative mathematical modelling for MAP design of fresh produce. Mathematical models on product respiration rate and package permeability have been compiled into a comprehensive database and by using engineering principles were integrated on a web-based software platform (Pack-in-MAP®) which can be used to design and simulate the packaging needs for fresh produce. The aim of this paper was to illustrate the use of Pack-in-MAP® software and additionally simulate and validate the MAP design for fresh whole strawberry. The experimental and predicted gas compositions during storage were closely matching thereby showing the ability of Pack-in-MAP® software to determine the ideal packaging solution and predict the gas composition inside the package during storage period. Further, it can also evaluate the impact of temperature variation, and variability of product/package on gas composition providing a system which allows selection of suitable packaging materials for fresh produce. The Pack-in-MAP® software can be used to test several solutions on a value-for-money basis in order to achieve results while minimising costs and avoiding costly trial-and-error approaches. [Copyright &y& Elsevier]

Abstract: This paper discusses results of simulations conducted for non-contacting face seals showing the influence of the operational parameters on the distributions of temperature in the structural elements and the fluid film separating the sealing rings. The mathematical model developed for noncontacting face seals consists of cross-coupled differential equations with partial derivatives. We solved it analytically, taking into account various boundary conditions. The heat equations were solved using the method of separation of variables. The derived relationships were based on Bessel functions of the first and second kinds. By defining the relationships describing the distributions of temperature in the sealing rings and the fluid film separating them, we could determine the effect of the operational parameters on the variability of temperature fields. Confirmation of the simulation results with experimental data is essential to better recognize the phenomena taking place in the sealing assembly and improve the design of non-contacting seals so that they can be used in various industrial applications. In this paper, we also describe a specially designed test stand for compensation of the misalignment of the flexibly mounted ring and automatic control of the radial clearance height. The test stand can also be used to verify the results of analytical studies. [Copyright &y& Elsevier]

The gravimetric moisture content of peat is the main factor limiting the ignition and spread propagation of smouldering fires. Our aim is to use controlled laboratory experiments to better understand how the spread of smouldering fires is influenced in natural landscape conditions where the moisture content of the top peat layer is not homogeneous. In this paper, we study for the first time the spread of peat fires across a spatial matrix of two moisture contents (dry/wet) in the laboratory. The experiments were undertaken using an open-top insulated box (22 × 18 × 6 cm) filled with milled peat. The peat was ignited at one side of the box initiating smouldering and horizontal spread. Measurements of the peak temperature inside the peat, fire duration and longwave thermal radiation from the burning samples revealed important local changes of the smouldering behaviour in response to sharp gradients in moisture content. Both, peak temperatures and radiation in wetter peat (after the moisture gradient) were sensitive to the drier moisture condition (preceding the moisture gradient). Drier peat conditions before the moisture gradient led to higher temperatures and higher radiation flux from the fire during the first 6 cm of horizontal spread into a wet peat patch. The total spread distance into a wet peat patch was affected by the moisture content gradient. We predicted that in most peat moisture gradients of relevance to natural ecosystems the fire self-extinguishes within the first 10 cm of horizontal spread into a wet peat patch. Spread distances of more than 10 cm are limited to wet peat patches below 160% moisture content (mass of water per mass of dry peat). We found that spatial gradients of moisture content have important local effects on the horizontal spread and should be considered in field and modelling studies. [ABSTRACT FROM AUTHOR]

In this paper we present the methodology for assessing the ionic liquids’ viscosity at six temperature points (25, 35, 45, 50, 60 and 70 [°C]), which utilizes only the in silico approach. The main idea of such assessment is based on the “correction equation” describing the correlation between experimentally measured viscosity and theoretically derived density (calculated with use of molecular mechanics), given at 6 different temperature points. The equation allows for recalculating the viscosity of ILs at 25 °C to determine the viscosity of ILs at other, higher temperature. Since the equation needs the basic viscosity value (at 25 °C) we additionally developed QSPR model that allows predicting it. According to our model, the viscosity of ILs is dependent to the size and branching of the cation and size, shape, symmetry and the vertical electron binding energy of IL’s anion. With those novel tools, it is possible to predict the viscosity of new ionic liquids at different temperatures without the need of experimental measurements. [ABSTRACT FROM AUTHOR]

Abstract: Municipal solid waste landfill barrier systems often comprise a combination of geosynthetics and mineral layers. Throughout the last twenty years there has been extensive research on the interactions between the materials and on performance of the geosynthetics including aspects of durability. This research has resulted in significant advances in the design and specification of landfill lining systems. However, to date there has been limited research carried out on in situ landfill lining system behaviour. Measured behaviour from field scale trials and of in service operation can provide valuable information on landfill lining system performance and allow a better understanding of composite material behaviour. Although many numerical modelling programs are applied to evaluate lining system stability and integrity, data to validate these models is currently limited. This paper highlights the data required to validate numerical models and instrumentation techniques that may be used to acquire this information. The paper focuses on geotechnical instrumentation deployed on the side slope lining system at the Milegate Extension Landfill, UK. The instrumented lining system comprises 1.0 m of compacted clay, a 2 mm double textured high density polyethylene geomembrane, a nonwoven geotextile and a sand cover soil layer. Instrument selection and problems associated with acquiring consistent, reliable and valuable data in a field environment are discussed, as are the challenges and problems that occur when preparing a full scale experiment. Sources of uncertainties within readings are highlighted. Additionally, initial results collected during sand veneer layer placement on the slope are presented. These demonstrate acceptable instrument performance over a 2 year period. Measured behaviour highlights the significance of geomembrane strains driven by temperature changes, generation of post peak strengths at interfaces during fill placement on the side slope due to relative displacement at interfaces between components, and mechanisms of stress redistribution in the geomembrane that result in time dependent changes in strain under constant load and temperature conditions. [Copyright &y& Elsevier]

Abstract: Steam circulation in SAGD start-up processes has significant impacts on the whole SAGD process. The start-up aims to heat the fluid sufficiently to improve oil mobility to establish communication between the injector and the producer. An efficient and economic approach is needed by the industry to identify the communication between the well-pair and to minimize the steam-circulation period. Knowing the hot-zone size and shape distribution formed by steam circulation along the horizontal wellbore can also help better understand the start-up process and obtain a long-term SAGD performance. This paper proposes a new technique called Transient Temperature Analysis (TTA) to estimate the hot-zone size and shape by interpreting the temperature falloff data in the injector and the producer obtained from fiber optics after the wells are shut in. Both forward and inverse mathematical models are presented to facilitate the application of this technique. Three forward mathematic models, two-system model with a hot-zone and a cold-zone, three-system model with an additional transition zone, and superposition of multiple two-systems model for irregular hot-zone shape were developed to model the temperature falloff. An inverse model is proposed to automatically interpret the hot-zone size through matching the temperature falloff. Sensitivity analysis shows that the hot-zone size and shape and observing location strongly affect the temperature falloff behaviors. Synthetic case studies suggest that the proposed models can be used to identify the hot-zone size and shape around the producer and the injector, and then to identify whether those hot-zones have established communication. Because of the ready-to-use temperature data and the semi-analytic solutions presented in this paper, the TTA technology can provide fast and economical estimation of the hot-zone size. [Copyright &y& Elsevier]

Abstract: Research on shape–memory polymers (SMPs) has been actively conducted for more than three decades. Recently, interest in this area has intensified. Even though there have been a number of related review papers published in the past 3 years, a generalized view on the important aspects of SMPs that would give a holistic picture of this promising area of research is still lacking. This paper will provide a comprehensive review that integrates the achievements in studying SMPs and their derivatives, such as composites and compound structures, as well as their current applications. Concepts, principles/modelings, structures and related synthesis methods, applications and future trends will be examined. [Copyright &y& Elsevier]

Abstract: The paper presents the assumptions and theoretical background of analytical method of estimation the coordinate measurement uncertainty. The uncertainty for each characteristic is estimated separately. Mathematical model for each characteristic uses the minimal number of so-called “characteristic points” of the measured workpiece. Each characteristic is defined by a formula presented in a form where it is a function of coordinates’ differences’ of characteristic points. The uncertainty budget for the coordinates’ differences includes influences of particular geometrical errors of CMM, probing system errors, as well as temperature errors. The applied algorithms of uncertainty estimation use the type B method according to the rules of GUM. The paper presents also the operational rules of software for the estimation of coordinate measurements uncertainty. The software covers 48 measurement models. The software is oriented on the ease of use. All necessary information concerning the accuracy of the used CMM are implemented by software provider. The basic version of the software includes the minimal database of the styli, but on demand the styli of particular customer can be implemented. [Copyright &y& Elsevier]

Abstract: This paper presents an implantable biomedical device for the localized killing of cancer cells through hyperthermia. Heating, accomplished via resistive heating, is modeled using numerical heat transfer techniques, which are tested under experimental conditions. The effect of temperature in the therapeutic domain of 37 to 45°C as studied on breast cancer cell line MDA-MB-231 is also reported. The results show the predicted temperature variations are consistent with temperature measurements obtained from the experimental set-ups. The paper also examines the effects of isothermal heating on the cell morphology. Isothermal heating is shown to cause significant physical changes in the cell cytoskeleton. Finally, the paper explores the effects of hyperthermia on cell growth and cell death under isothermal and cyclic conditions. The underlying effects of heat shock protein expression are elucidated before discussing the implications of the results for cancer treatment via localized hyperthermia. [Copyright &y& Elsevier]

Abstract: Oxy-fuel combustion is considered as a promising solution to reduce greenhouse-gases and pollutant emissions. The main advantage of oxy-fuel combustion over other technologies for pollution reduction from pulverized coal combustion is that it can be applied to the existing coal-fired power plants. However, switching from conventional to oxy-fired coal combustion brings significant challenges. One of the most important is change of pulverized coal ignition characteristics. This paper presents the results of experimental and numerical analysis of ignition phenomena under oxy-fuel conditions. The main focus of the presented paper is to evaluate the effectiveness of the mathematical devolatilisation sub-model, in predicting the ignition point of pulverized coal flames under oxy-firing conditions. Regarding this, the performance of several devolatilisation models, from simple to more complex ones, in predicting ignition point position have been investigated. Numerically determined values of the ignition point position, and ignition temperature for various O2–N2 and O2–CO2 conditions were compared with experimental data from the laboratory ignition test facility. Obtained results pointed out that network devolatilisation models (CPD and FG) give more accurate results in comparison with standard devolatilisation models (single rate and two competing rates). The best performance is achieved using FG devolatilisation model. Thus, newly implemented FG model will be used for future numerical simulations of oxy-fuel pulverized coal combustion on 0.5MW pilot plant facility. [Copyright &y& Elsevier]

Abstract: Many drilling muds and crude oils are known to be thixotropic. Under a wide range of pressures, temperatures and flow regimes, they display unusual complex flow properties when flowing through wells (crude oils and drilling muds) and during storage and pipeline transportation (crude oils). Understanding and modeling the deviation from Newtonian behavior of drilling muds and crude oils are essential in accurately and optimally designing the flow systems associated with these fluids. Despite an impressive amount of experimental and rheological modeling studies concerning the non-Newtonian drilling mud and crude oil behavior, mathematical modeling studies taking into account their thixotropic properties are rare. In addition, there was no literature review of the knowledge gained to date. Thus, a review paper on studies addressing the mathematical modeling of thixotropic drilling mud and crude oil flow in wells and pipelines will pinpoint the challenges and limitations encountered in such studies. This will hopefully trigger further development and new research topics. This review paper focuses mainly on mathematical modeling studies concerning the well and pipeline flow of thixotropic drilling muds and crude oils. After describing how thixotropy is understood today inside and outside of the petroleum industry community, several mathematical models available in the literature are examined. Finally, challenges, limitations, and potential areas for the development of these models are presented. [Copyright &y& Elsevier]

Abstract: Infrared (IR) imaging represents an innovative sensing modality to study the interior structure of metallic glasses such that hidden defects causing fracture can be identified and handled in a controlled way. In this paper, the compression-compression-fatigue study is performed on a bulk-metallic glass (BMG), and the fatigue-damage evolution is recorded by an IR camera. Since IR images can only capture the surface temperature on the material, how to obtain the temperature-evolution information of internal defects through the interpretation of the surface temperature remains a challenging problem. In this paper, we consider the surface-temperature readings as a result of multiple heat sources (e.g., defects) emitting energy simultaneously from inside the BMG with each heat source having its own unique temperature-evolution pattern. This concept is a key enabler to go beyond what is immediately measureable on the surface of the material. We interpret the surface-temperature evolution over time across the spatial domain using a linear-mixing model and presents a robust unsupervised unmixing algorithm such that joint effects of hidden events (i.e., heat sources) can be identified, providing the prevailing support to the understanding of the IR images of BMGs during cyclic loading. In addition, we tackle the challenging issue of the structural characterization of defects through functional imaging techniques using a thermal-electric analog. Thus, the fatigue deformation and fracture behavior can be further studied. Moreover, the fatigue mechanisms of BMGs will be suggested. [Copyright &y& Elsevier]

Abstract: This paper presents a novel approach to model the transient behavior of solid-oxide fuel cell (SOFC) stacks in two and three dimensions. A hierarchical model is developed by decoupling the temperature of the solid phase from the fluid phase. The solution of the temperature field is considered as an elliptic problem, while each channel within the stack is modeled as a marching problem. This paper presents the numerical model and cluster algorithm for coupling between the solid phase and fluid phase. For demonstration purposes, results are presented for a stack operated on pre-reformed hydrocarbon fuel. Transient response to load changes is studied by introducing step changes in cell potential and current. Furthermore, the effect of boundary conditions and stack materials on response time and internal temperature distribution is investigated. [Copyright &y& Elsevier]

Abstract: This paper presents the calculation of the power of solar rays that pass through the window of an observed room and their impact on warming up and lighting of the room. The calculations were performed using a mathematical model that takes into account the geographical position of the object, time zone, orientation of windows, day of the year, and current time. This paper also includes the calculation of geometry of the solar radiation and its intensity, artificial light and cooling/heating demands. Based on data from above, the optimization of blind tilt angle was performed to achieve the best possible brightness of the room and energy savings when heating or cooling, depending on ambient temperature. Optimization was performed using a genetic algorithm and fuzzy logic. After an analysis of the results obtained from optimization of the blind tilt angle, an algorithm for blinds control was developed in order to achieve energy savings and comfort in the observed room. Based on the derived conclusions, an UML diagram was made that describes the algorithm for determining optimal blind tilt angle. [Copyright &y& Elsevier]

Abstract: This paper concerns the mathematical and numerical modeling of solidification process of pure metals. Such process takes place without development of “mushy zone”, which very often occurs during solidification of alloys. The model is based on the finite element method (FEM) and takes into account the existence of a sharp solidification front which moves according to time. The paper discusses how to include the conditions of continuity on the moving interface as well as the technique of front tracking based on the level set method (LSM). The paper also presents the results of computer simulations of the solidification process of pure copper. Two in-home solvers for one- and two-dimensional problems were built. Both of them are based on FEM. The correctness of the front tracking technique was checked by comparing the results obtained from 2D simulation to 1D simulation. Furthermore, the final calculation process was done for the two-dimensional area at different temperatures on the boundaries to demonstrate the effectiveness of the solver for a complex shape of the solidification front. [Copyright &y& Elsevier]

Abstract: This paper describes a simple energy balance model based on static parameters to calculate the COP of an adsorption chiller. The model leads to an analytical equation using basic information about the working pair, the chiller design and the operation temperatures. A set of dimensionless key figures is derived for better understanding of the influence of physical parameters on the COP. These key figures are investigated in this paper. In contrast to absorption chillers, desorption is not an isobaric process in adsorption chillers. The influence of the path is discussed in the limits of isobaric and isothermal desorption. Furthermore, the model is applied to a set of new material data, focussingfocussing on methanol/activated carbon as the working pair. This working pair makes refrigeration below 0 °C feasible. This paper is the second of two articles about the measurement and evaluation of methanol/activated carbon for cooling purposes in adsorption chillers. The first part contains the experimental description and the thermophysical properties of methanol/activated carbon [Copyright &y& Elsevier]

Abstract: In this paper the kinetic description of a viscous reacting flow of CO2/CO/O2/C/O mixture is proposed on the basis of the kinetic theory methods. Vibrational excitation of CO2, CO and O2 molecules as well as non-equilibrium dissociation, recombination and exchange reactions are taken into account. A five-temperature model for a non-equilibrium flow is derived from the kinetic theory and used for evaluation of transport properties of the considered mixture at different temperatures and mixture composition. The paper presents the closed set of equations for macroscopic parameters, expressions for transport and source terms suitable for numerical simulations and results of calculations. The influence of non-equilibrium kinetics and mixture composition on transport properties in a flow is discussed. [Copyright &y& Elsevier]

Abstract: This paper presents the performance evaluation of a novel sensor designed to measure the in situ viscosity of a fluid flowing at downhole conditions. The device provides a mechanism to allow the passage of solid particles (i.e. sand) and has a self-cleaning ability should any build-up of these particles restrict the flowing area. The sensor was assembled in a closed flow loop to prevent measurement error due to partial vaporization of the samples at higher temperatures, and it was tested and calibrated with mixtures of glycerin and water. Differential pressures, flow rates and temperatures were acquired and used to determine the viscosity of two crude oils (and mixtures of those) with viscosities ranging from 0.001 to 0.03 Pa.s (1 to 30 cp ) and temperatures from 37.8 to 71.1 °C (100 to 160 °F). Flow rates were controlled to maintain linearity in the differential pressure response to ensure a laminar flow regime. Viscosity measurements were validated with independent measurements using a Brookfield viscometer and the agreement was within 2%. Using data from this sensor, new viscosity mixing rules were developed to allow determination of mixture compositions from viscosity measurements or mixture viscosities for given compositions. This paper also presents a generalized mathematical model to describe the performance of the sensor with Newtonian and non-Newtonian fluids. The model characterizes the response of the sensor as a function of the parameters from a power-law model rheological description and the geometry of the device. The experimental data suggest the validity of this model for predicting the sensor response under realistic operating conditions. The model can be used to calculate optimum dimensions to fabricate a device for customized applications. Potential applications include the estimation of diluent to be added to a more viscous fluid to achieve a target viscosity reduction, fluid identification from wireline formation testers, smart well fluid monitoring, enhanced mud logging, and fracture fluid characterization. [Copyright &y& Elsevier]

Abstract: This paper aims at developing an analytical model for the coupled heat and mass transfer processes in a counterflow Reversibly Used Cooling Tower (RUCT) based on operating conditions, which is more realistic than most conventionally adopted Merkel approximations. Temperature and moisture content differences are chosen as the driving forces of heat and mass transfer correspondingly and a system of specific difference equations is developed to solve the model more efficiently. The model is investigated by using an iterative algorithm, which is validated with the experimental data reported. The analytical model also accommodates the direct and quick calculation of air and water temperature profiles, moisture content of air and the water mass flow rate change along the vertical length of the RUCT. With the aid of the developed model, the thermal behavior of the counterflow RUCT under various operating and environmental conditions is also studied in this paper. The results reveal that the proposed model can provide a theoretical foundation for practical design and performance evaluation of counterflow RUCT. [Copyright &y& Elsevier]

Abstract: This paper presents the approximate analytical models of temperature and thermal stress in a two-dimensional axis-symmetry object. The models can be used to deal with some non-linear factors caused by temperature-dependent properties using multiple parameter perturbation method. Two cases have been used to test the models proposed in this paper. The first case study is the comparison of analysis of the rotor with our models and FEM (finite element method) and it is shown that our models have a satisfactory accuracy. The second case is the application of our models to sensitivity studies. The models proposed reduce computational time significantly compared with FEM method and hence can be used for online analyzing of thermal state of a two-dimensional axis-symmetry object and inverse heat conduction problems. [Copyright &y& Elsevier]

Abstract: Gas from coal gasification contains less hydrogen than from other syngas production methods. An attractive option is its further hydrogen enrichment for pure hydrogen production in a membrane reactor (MR) by water gas shift (WGS). The goal of the present study was to analyse MR fed with coal derived gas. Simulations for feasible membrane permeation parameters revealed that to get high conversion above 90% a relatively high S/C should be applied. Moreover, hydrogen recovery is in this case low (below 30%) so for hydrogen production an additional H2 separation after the MR should have been applied. The paper also shows that a clear advantage of counter- over co-current flow configuration in MR appears only for low pressure in the reaction zone. The realistic feasible Pd–Cu–Ni membrane parameters result in a rather large membrane area, thus possible heat exchange between the reaction and permeation zone can have important influences on temperature profiles in the MR. This cooling effect could lessen excessive temperature increase in the reaction zone. Results for other than single step MR configurations are also presented in the paper. It is stated in conclusion that future successful application of MRs for coal-derived gas depends on development of not only new catalysts with adequately wide operational temperature range, but also membranes with a high enough permeability. [Copyright &y& Elsevier]

Abstract: Thermal fatigue in Pressurized Water Reactor plants has been found to be very acute in some hot/cold Tee junction mixing zones. Large Eddy Simulation (LES) can be used to capture the unsteadiness which is responsible for the large mechanical stresses associated with thermal fatigue. Here one LES subgrid model is studied, namely the Dynamic Smagorinsky model. This paper has two goals. The first is to demonstrate some results obtained using the EDF R&D Code Saturne applied to the Vattenfall Tee junction benchmark (version 2006) and the second is to look at the effect of including synthetic turbulence at the Tee junction pipe inlets. The last goal is the main topic of this paper. The Synthetic Eddy Method is used to create the turbulent inlet conditions and is applied to two kinds of grids. One contains six million cells and the other ten million. The addition of turbulence at the inlet does not seem to have much effect on the bulk flow and all computations are in good agreement with the experimental data. However, the inlet turbulence does have an effect on the near wall flow. All cases show that the wall temperature fluctuation and the wall temperature/velocity correlation are not the same when a turbulent inlet condition is used. Inclusion of the turbulent inlet condition moves the downstream location of the maximum temperature/velocity correlation by 1cm and reduces its magnitude by 10%. This result is very important because the temperature/velocity correlation is closely related to the turbulent heat transfer in the flow, which is in turn responsible for the mechanical stresses on the structure. Finally we have studied in detail the influence of the turbulent inlet condition just downstream of the mixing zone. We show the influence of including turbulent inlet condition on the structure of the flow . [Copyright &y& Elsevier]

Abstract: The temperature dependency of ocean–atmosphere gas transfer velocities is commonly estimated in terms of Schmidt numbers, i.e. the ratio of kinematic viscosity to diffusivity. In numerical models least square regressions are used to fit the limited number of experimentally derived Schmidt numbers to a function of temperature. For CO2 a well established fit can be found in the literature. This fit constitutes an integral part in standardized carbon cycle simulation projects (e.g. C4MIP, OC4MIP, ). However, the fit is valid only in the range where diffusivity measurements exist, i.e., from 0 to about 30°C. In many climate warming simulations like e.g. the MPI contribution to the fourth Intergovernmental Panel on Climate Change Assessment Report (IPCC AR 4), sea surface temperatures largely exceed the validated range and approach or even reach the range, where the standard fits leave the physically meaningful range. Thus, this paper underlines the demand for new measurements of seawater diffusivities for CO2 and other trace gases especially for the temperature range >30°C. In this paper we provide improved fits for the temperature dependence of the Schmidt number. For carbon dioxide our fit is compared to the established fit under identical climate change simulations carried out with the 3D-carbon cycle model HAMOCC. We find that in many tropical and subtropical high temperature regions the established fit leads to unrealistically short adaption times of the surface water pCO2 to altered atmospheric pCO2. In regions where the local oceanic pCO2 is not primarily controlled by the atmospheric boundary pCO2 but by other processes such as biological activity, the atmosphere ocean pCO2 gradient is clearly underestimated when using the established fit. The effect on global oceanic carbon uptake in a greenhouse world is rather small and the potential climate feedback introduced by this bias seems to be negligible. However, the bias will clearly gain in significance the more regions warm up to over 30°C. On a regional scale, especially in coastal regions at low latitudes, the effect is not negligible and a different steady state is approached. [Copyright &y& Elsevier]

Abstract: In this paper, a low-temperature high-pressure triaxial test system including pressure crystal device (sample preparation system) was developed, in which the conditions of hydrate stabilized can be maintained. To determine the stress strain behavior of methane hydrate, the triaxial shear tests were performed under the condition of strain rates of 1.5%/min, temperatures θ =−5, −10, and −20°C and confining pressures P =2.5, 5 and 10MPa. The preliminary results show that the stress strain curves can be divided into two stages: the rapid structural damage stage and the complete structural damage stage (or the yield stage). Based on the experimental and analysis results of stress strain behavior of triaxial tests, this paper proposes a modified nonlinear elastic Duncan–Chang constitutive model suitable for artificial methane hydrate. The modified model takes into account the effect of temperature and confining pressure as well as hydrate structure on the stress strain behavior. By comparing experimental with simulation results, the validity of model had been evaluated. [Copyright &y& Elsevier]

Abstract: The rising popularity of incineration of municipal solid waste (MSW) calls for detailed mathematical modeling and accurate prediction of pollutant emissions. In this paper, mathematical modeling methods for both solid and gaseous phases were employed to simulate the operation of a 450t/d MSW-burning incinerator to obtain detailed information on the flow and combustion characteristics in the furnace and to predict the amount of pollutant emissions. The predicted data were compared to on-site measurements of gas temperature, gas composition and SNCR de-NO X system. The major operating conditions considered in this paper were grate speed and oxygen concentration. A suitable grate speed ensures complete waste combustion. The predictions are as follows: volatile release increases with increasing grate speed, and the maximal value is within the range of 700–800kg/m2 h; slow grate speeds result in incomplete combustion of fixed carbon; the gas temperature at slow grate speeds is higher due to adequate oxygenation for fixed carbon combustion, and the deviation reaches 200K; NO X emission decreases, but CO emission and O2 concentrations increase, and the deviation is 63%, 34% and 35%, respectively. Oxygen-enriched atmospheres promote the destruction of most pollutants due to the high oxygen partial pressure and temperature. The furnace temperature, NO production and CO emission increase as the oxygen concentration increases, and the deviation of furnace exit temperature, NO and CO concentration is 38.26%, 58.43% and 86.67%, respectively. Finally, oxygen concentration is limited to below 35% to prevent excessive CO and NO X emission without compromising plant performance. The current work greatly helps to understand the operating characteristics of large-scale MSW-burning plants. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, four 3-D finite element models are developed to simulate the whole rod rolling process of GCr15 steel. The distribution and evolution of different field-variables, such as effective strain, effective strain rate and temperature, are obtained. Based on the simulated results and the microstructure evolution models of the steel, the paper designs a FORTRAN program to predict the evolution of recrystallization behavior and austenite grain size in rolled piece during the rolling. The surface temperatures of rolled piece calculated by FEM agree well with measured values. Comparison between calculated values and measured ones of grain size shows the validity of the program. [Copyright &y& Elsevier]

Abstract: A number of publications have characterized low-alloy steel welds by specifying the power per unit length. This paper uses a 3D numerical model to compute the transient temperature and evolution of the microstructure in six welds with the same weld power per unit length of weld but with different weld powers. The results show that the welds have large differences in their transient temperature field and the fields for phase fractions of gamma, martensite, bainite and ferrite–pearlite phases. Also the gamma phase grain size and hardness profiles are quite different. The reason for the differences is that with high welding speeds, the heat flows primarily in the two-dimensions that are normal to the weld path and cools more slowly near the weld pool than in welds made with low welding speeds where the heat flows in three-dimensions and cools more quickly. However, there is a region in the heat-affected zone farther from the weld pool where the time to cool is higher at lower powers and lower welding speeds. The longer times at higher temperatures causes more growth of gamma grain size. The larger gamma grain size reduces the density of nuclei for the austenite to ferrite transformation and thus more gamma can be present when the martensite start transformation is reached. At low weld powers, the hardened zone is wider, deeper and shorter but the maximum hardness is attained in the highest power welds in the coarse grained heat-affected zone that is primarily a martensite and bainite microstructure. This paper studies the extent to which the ratio of power per unit length of weld is not a unique descriptor of a weld. [Copyright &y& Elsevier]

Abstract: The hot water temperature that maximizes the overall instantaneous efficiency of a solar cooling facility is determined. A modified characteristic equation model is used and applied to single-effect lithium bromide–water absorption chillers. This model is based on the characteristic temperature difference and serves to empirically calculate the performance of real chillers. This paper provides an explicit equation for the optimum temperature of vapor generation, in terms of only the external temperatures of the chiller. The additional data required are the four performance parameters of the chiller and essentially a modified stagnation temperature from the detailed model of the thermal collector operation. This paper presents and discusses the results for small capacity machines for air conditioning of homes and small buildings. The discussion highlights the influence of the relevant parameters. [Copyright &y& Elsevier]

Abstract: This paper presents a numerical study on laminar forced convection of water in offset strip-fin microchannels network heat sinks for microelectronic cooling. A 3-dimensional mathematical model, consisting of N–S equations and energy conservation equation, with the conjugate heat transfer between the heat sink base and liquid coolant taken into consideration is solved numerically. The heat transfer and fluid flow characteristics in offset strip-fin microchannels heat sinks are analyzed and the heat transfer enhancement mechanism is discussed. Effects of geometric size of strip-fin on the heat sink performance are investigated. It is found that there is an optimal strip-fin size to minimize the pressure drop or pumping power on the constraint condition of maximum wall temperature, and this optimal size depends on the input heat flux and the maximum wall temperature. The results of this paper are helpful to the design and optimization of offset strip-fin microchannel heat sinks for microelectronic cooling. [Copyright &y& Elsevier]

Abstract: In this paper, infrared thermal testing and mathematical models for studying the temperature distributions of the high-speed waterjet in air are presented. The waterjet temperature distributions are investigated under different pressures. We describe the experiments in which we apply the infrared thermal imager to obtain the infrared thermal images of the high-speed waterjet. By denoising these infrared thermal images and fitting data, we obtain the isotherms and the temperature variation curves as a function of the distances form the nozzle outlet. In order to calculate the shear stress within the water air boundary layers, multi-phase models are developed. Due to the sophisticated patterns of the multi-component model, the numerical computation is used to obtain the velocity and temperature distribution of the waterjet. The results indicate that the temperature distributions were similar when the pressure is greater than the threshold pressure. This fact is proved by further theoretical computation and experiments data. The paper revealed that the velocity profiles were similar to the temperature profiles in the radial direction at the same cross-sections. [Copyright &y& Elsevier]