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Cold spray is widely applied for the dimensional recovery of damaged parts and components due to the advantages in avoiding local melting, depressing thermal stress and oxidation, and high bonding strength. In this work, a novel trajectory applicable to cold spray for repairing damaged workpiece was proposed for the purpose of improving productivity and reducing cost in machinery work. The Archimedean spiral was chosen as the basis for building this novel trajectory due to the constant distance between two successive turns. This novel trajectory was composed of two symmetrical Archimedean spirals adapted to the damage contour by scaling method. Nozzle speed at each target point was compensated based on the corresponding crater depth. With this novel trajectory, the experimental validation of an Al5056 coating depositing on a damaged Al2027A substrate was conducted. The results showed that the damaged workpiece was perfectly repaired and the coating had good quality in terms of porosity and bonding strength. Therefore, cold spray with the spiral trajectory and adapted nozzle speed is an effective way to repair damage components. Comparing with the round-trip trajectory, Archimedean spiral trajectory is able to significantly save process duration as well as consumption of powder and spray system energy, which leads to the increase of spray efficiency.

The residual stress and distortion caused by non-uniform temperature distribution has limited the application of cold spray (CS) technique as an effective additive manufacturing and damage repair method for large-scale components. In order to investigate the influence of heat accumulation on coating quality, two types of CS Ni coatings with different building dimensions were deposited onto substrates. The type II Ni coatings with smaller fabrication size possess a fully dense microstructure without cracks, while the type I coatings with larger size show a significantly higher porosity value. The type II coatings show relatively higher microhardness. The tribological tests show that the type II Ni coatings present a better wear resistance with lower coefficient of friction and lower wear rate. The distinct worn morphologies show that the lower microhardness and porous microstructure of type I coatings lead to numerous delamination and exposure of interior coating. According to the temperature history recorded by infrared imaging camera, higher average temperature was found at the type II coatings due to enhanced heat accumulation of coating/substrate system at the short nozzle movement. The increased particle plastic deformation can further promote the coating densification rate and further ameliorate the coating quality. It can be summarized that the nozzle trajectory and deposition strategy can affect the temperature distribution and determine the coating qualities. This work provides a potential guidance for the optimization of coating quality by cold spraying additive manufacturing.

This work aims to measure the thermodynamics of a main cabin ventilation system in a JU-2000E jack-up offshore platform. A three-dimensional (3D) physical model of the ventilation system was established, and the computational fluid dynamics (CFD) software (ANSYS FLUENT) was used to calculate the model thermodynamics. Numerical analysis was performed to investigate the influence mechanisms of the ventilation factors such as ventilation temperature and volume on the ventilation performance. The analysis results demonstrate that (1) top-setting of the exhaust vents is more effective than the side-setting in terms of high temperature reduction, (2) small ventilation temperature and volume can improve the ventilation efficiency, and (3) proper shutdown selection of the backup diesel engine can enhance the ventilation performance. Furthermore, the effect of humidity for the ventilation air was investigated. Lastly, an experimental platform was developed based on the simulation model. Experimental tests were carried out to evaluate the shutdown selection of the backup engine and have shown consistent results to that of the simulation model. The findings of this study provide valuable guidance in designing the ventilation system in the JU-2000E jack-up offshore platform.

In this work, the techniques of cold spray (CS) and high velocity oxygen-fuel (HVOF) were employed to fabricate Ni/FeSiAl soft magnetic composite (SMC) coatings by using Ni-coated FeSiAl composite powder. The microstructural features were characterized in terms of scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses. The tribological and magnetic properties of the Ni/FeSiAl SMC coatings were also comparatively studied. Results showed that the CS coating exhibited higher particle deformation and much higher density, whereas the HVOF coating showed more visible defects and slightly higher oxide content. Both CS coating and HVOF coating resulted some loss of FeSiAl particles during deposition, while a higher content of FeSiAl particles was achieved in the HVOF composite coating, indicated a higher deposition efficiency of FeSiAl particles during HVOF deposition. According to the XRD analysis, both SMC coatings had no obvious oxidation and phase transformation during deposition processes. The EDS analysis proved partially melted particles during HVOF deposition. Tribological tests revealed a better wear performance of the CS coating as a result of the enhanced plastic deformation and microhardness. The HVOF coating showed a better magnetic performance, with a lower coercivity and a higher saturation magnetization compared to those of CS coating. This can be explained by a higher retainability of FeSiAl particles and a smaller strain stress generation during HVOF deposition.

This study demonstrates a two-step laser cladding process for copper substrates in which cold spraying is used as a powder preplacing method to overcome problems associated with the high laser reflectivity of copper as well as the effects of high-temperature oxidation. In the first step of the process, Inconel powders are cold sprayed onto pure copper, producing a layer with a thickness of about 250 μm and a porosity of 0.88%. This is followed by a 3.5 kW laser remelting treatment using a 1030 nm laser with a spot size of 2.5 mm. Examination and testing of the as-sprayed and remelted layers show how the laser treatment improves coating microstructure, hardness, density, and metallurgical bonding.

This paper proposes a study on the hull structure optimization of a semi-submersible medical platform. The hull structure sizes have great important effect on the cost, hydrodynamics, global, and manufacture of the whole semi-submersible platform. In this paper, the economy, lightweight and higher stability should be ensured for the medical platform during the optimization design process. The hull sizing optimization process is modeled as a multivariable minimization problem, which is minimizing the hull structure weight, the heave response, and the roll response. The surrogate model method is introduced to obtain the relationship between the design variables and output variables, which reduced the time-consuming induced by the numerical simulation and improved the optimization efficiency. A multi-objective optimization for the hull structure is developed by using the gray correlation analysis to evaluate the weight of three optimization objects. At last, the optimization solutions are achieved in the form of Pareto set. According to the optimization results, the changing relations between the sizes of the deck, column, pontoon and draft with the total weight, and the heave and roll response can be determined.

In worldwide, to overcome a future shortage of resource, deep-sea mining (DSM) system and technology have been developed for great commercial values. As a core component, deep-sea mining vehicle (DSMV) plays an important role in deep-sea operation. Based on the development in last decades, this paper presents the significance and challenge of DSMV and reviews the existing deep-sea mining system in sea trial. Firstly, the dynamic analysis of DSMV is reviewed, including dynamic modeling method, track characteristics and mining collection systems. The interaction considering deep-sea sediment to the tracked DSMV performance is discussed, which is well to understand the work mechanisms of DSMV. Then, for engineering application in deep-sea environment, key control strategies of DSMV are reviewed in the field of dynamic motion control, path control, navigation, and positioning control, which aims to adapt to deep-sea operation. In the end, some existing issues and future study priorities are proposed. This paper may provide a comprehension of the current research status of deep-sea mining system, which enlightens the future development for balancing technology and deep-sea ecological environment.

Three nickel (Ni) powders, i.e. gas-atomized spherical Ni (GA-Ni), carbonyl irregular Ni (C-Ni), and electrolytic dendritic porous Ni (E-Ni), were sprayed on magnesium alloys by an in-situ micro-forging assisted cold spray method. Although all deposited coatings present extremely low porosity, the C-Ni and E-Ni coatings reveal poorer inter-particle bonding than GA-Ni coating. Electrochemical tests reveal that the inter-particle gaps will act as fast pathways for the corrosive media to penetrate the coatings, thereby the GA-Ni coating with intimate inter-particle boundaries can isolate the corrosive media for 3000 h and the C-Ni and E-Ni coatings fail after

The radiative energy loss accounts for roughly 70% of the energy loss in the polysilicon chemical vapor deposition (CVD) reactors and therefore takes up to about 25% cost in the production of polysilicon used for solar cells. In this work, cold spray (CS) process was used to deposit Ag coating with ultra-high infrared reflectance on inner wall of the CVD reactor to minimize the radiative losses. To solve the bond strength problem of depositing soft coatings on hard substrate by CS, a Ni buffer layer with medium hardness was introduced. Results show that Ag coating can be successfully deposited with a porosity lower than 0.1%. Even the as-sprayed Ag coating has a high near-infrared reflectivity of 92% which was much higher than that of a well-polished substrate surface (65%) suggesting an excellent radiation energy saving capacity. The bond strength of the Ag coating is significantly increased from 3.7 MPa to 35.4 MPa and the thermal shock resistance is improved from 22 ± 3 to over 150 cycles by the Ni buffer layer. The scientific methodology demonstrated here can be a cost effective approach to reduce the radiation energy losses in the polysilicon-CVD industry.

The vortex-induced vibration (VIV) of marine risers with large aspect ratio (length-to-diameter ratio) is a very complicated fluid-structure interaction phenomenon, which is the main cause of fatigue failure of marine risers. In order for the safe and stable operation of the riser systems, it is crucial to investigate the effect of the aspect ratio on the VIV response of the risers. In this study, the cross-flow VIV characteristics of a top tension riser with different aspect ratios are analyzed using a time domain simulation method. First of all, a riser model considering the fluid-structure interaction was established to calculate the natural vibration characteristics and compare with the theoretical result. Then, the cross-flow VIV response of the riser model in uniform and shear flows were respectively calculated and compared with the results of an experimental model. The numerical results were in good agreement with the experimental results. Subsequently, the developed riser model can be used to predict the cross-flow VIV response with different aspect ratios. Finally, the effects of the model scale and aspect ratio on VIV response were analyzed. The analysis results may provide a basis for selecting appropriate model scale and aspect ratio in establishing the riser simulation model.

Industrial robots are widely used in cold spray (CS) as well as thermal spray to produce various coatings by precisely controlling kinematic parameters during the process. However, the robot trajectory and its effect on the characteristics of CS deposits are important, but not fully studied. This article introduces four typical spray trajectories, including zigzag path, cross path, parallel path, and spiral path, to elaborate thick CS Cu deposits, and characterizes the corresponding Cu deposits, respectively. The experimental results revealed that the spray trajectories have a major influence on the associated thermal history and the residual stress distribution. However, no significant differences were found by the comparisons of microstructures and mechanical properties. In addition, due to high-velocity impact and extensive deformation of particles during the CS process, the as-sprayed Cu coating presented anisotropic characteristics that influenced the performances in different directions. The post heat treatment (PSH) cannot eliminate this characteristic but improves the mechanical performances to a certain extent. Therefore, reasonable planning of CS trajectory is an indispensable condition for obtaining a desirable coating.

A new theory was proposed to explain the interfacial bonding mechanism of hard Ni coating onto soft Al substrate. The experimental results indicate that the metal-to-metal contact and the consequent metallurgical bonding at the coating/substrate interface were absent in the single particle depositing but could be achieved in the full coating deposition. Based on this, it is proposed that the particle peening effect breaks the cracked oxides that remained at the coating/substrate interface into nano-pieces and promotes further deformation of materials. Thus, the pores caused by the bridge-like oxides at the interface are filled and the discontinuous metal-to-metal contact is achieved.

Investigation on a single particle deposition onto a polished substrate is an effective way to well understand the coating/substrate bonding mechanism in cold spray. But existing studies on this topic are always limited to the particle surface morphology and cross-section observation. This paper presents a methodology to directly observe the fractured contact surface between the cold sprayed particle and substrate. By this means, the particle/substrate fractured contact surfaces at different spray angles were obtained and analyzed. It was found that in the perpendicular spray dimple-like features as a sign of metallurgical bonding were formed at the surrounding of the central region on the fractured contact surface. However, for the angular spray, such dimple-like features only located at a small area of one side. Further analysis suggested that the high contact pressure is the dominant factor determining the particle/substrate metallurgical bonding quality and thus the formation of dimple-like features.

An analytical method is advantageous in designing and optimizing the humidifier of the humid air turbine cycle. In this paper, the energy effectiveness-NTU model for the countercurrent humidifier is built and verified by the 141 groups of test data obtained from an experimental facility of pressurized packing humidifier. The effect of pressure and inlet conditions including water/air mass flow rate ratio, inlet water temperature and inlet air wet bulb temperature on the heat capacity rate ratio and the energy effectiveness is analyzed. A sensitivity analysis is performed in order to indicate the key inlet parameter to improve the energy effectiveness of countercurrent humidifier. It is shown that the maximum deviation of the energy effectiveness calculated by the analytical method is 22.7% comparing to the experimental data. However, the maximum deviation is not more than 16% when considering the actual operating conditions for the humidifier of heat capacity rate ratio being greater than1.5. Heat capacity rate ratio changes monotonically with pressure and inlet parameters, and the energy effectiveness has an inflection point of minimum value when heat capacity rate ratio is equal to 1. Sensitivity analysis shows that water/air mass flow rate ratio is the most critical factor.

A range of Al/diamond metal matrix composites using advanced core-shell structured diamond powders was fabricated employing solid-state cold spray additive manufacturing technology. Cold spray technique combined with core-shell structured diamond particles has demonstrated excellent capability to produce dense Al/diamond composites with superior tribological properties. The core-shell structured diamond was easier to deposit than pure Al by cold spray, particularly under low particle impact velocity, implying high potentials as preferential feedstock for cold spray. The wear-resistance performance of the Al/diamond composites produced by nitrogen and helium were investigated. Wear test illustrated that the Al/diamond composites had superior wear-resistance properties comparable to the selective laser meting Inconel 625 and 17−4PH alloys. Higher diamond contents in the composites resulted in better wear resistance. Based on the worn track analysis via X-ray computed tomography, the role of the diamond reinforcement in improving the wear-resistance performance was also clarified.

Marine structures, such as ship hulls and offshore platforms, are basic elements in marine engineering. Due to the harsh ocean environment, marine structures are prone to adhesion and corrosion by marine biofouling. The biomimetic antifouling technology has been recognized as the most promising solution to marine biofouling, while there is still a long way to go to take this technology outside of research laboratories. In order to develop practical biomimetic antifouling techniques, this work presents a new water jet-based biomimetic antifouling model for marine structures to prevent the enrichment of biofouling. First, a semi-empirical formula is proposed based on the Schlichting self-similar solution to determine the effective width of the water jet. Then, a numerical simulation model is established to investigate the effects of the jet parameters (such as the jet aperture, jet velocity, and jet hole spacing) on the water jet distribution. Subsequently, visualization experiments are carried out to compare and validate the numerical simulation results. Finally, the simulation data are used to train a genetic neural network to predict the effective jet coverage ratio. The optimal parameters of the antifouling model are obtained corresponding to the largest effective jet coverage ratio. The findings of this study deliver a practical biomimetic antifouling technique for marine structures.

In the complex Ocean environment, wind load is the most important factor that should be addressed in the design of jack-up platforms. Although many efforts have been made to analyze the dynamics of jack-up platforms considering wind load effect, literature review shows that very limited work has been done to address the calculation of the wind load coefficient of each individual key component in a platform. Moreover, the influence of different wind speeds and directions under different working conditions of the platforms is not discussed clearly. To this avail, this paper investigates the wind load effect on the key components in a 400 ft jack-up offshore platform under three design conditions through normative calculation, numerical simulation and wind tunnel test. The wind force and torque of each key component (such as the crane, pile leg, and main hull) were obtained to calculate its wind load coefficient. The change rule of the wind load coefficient with different wind speeds and directions was discussed. The calculation results of the numerical simulation agreed well with these of the wind tunnel test, while the normative calculation results did not. The findings of this study may provide a basis for optimal design of jack-up offshore platforms.

Characteristics of creatures that have been evolved over long time in nature provide numerous inspirations to mankind for solving engineering problems. Inspired by biological principles, the development of bio-inspired surfaces for reducing the frictional resistance in fluid, such as the micro-groove surface of shark skin, the self-cleaning and antifouling surface of lotus leaf has attracted even more attention over the last couple of years. Based on the development of biomimetic drag reduction technology in recent decades, the present paper explains the morphology in brief and reviews the development of mainly three types of biomimetic surfaces, including non-smooth surface, superhydrophobic surface and water jet surface. The drag reduction effect and mechanism are discussed as well to understand the biomimetic drag reduction technology comprehensively. Moreover, the manufacturing methods are briefly summarized. In the end, the existing issues and future research priorities are proposed. This paper may provide a better comprehension of the current research status of bio-inspired drag reduction techniques.

A truncated octahedron structure LiNi0.5Mn1.5O4 is prepared by solid-state method. The result of X-ray diffraction (XRD) indexed to the truncated octahedron structure of LiNi0.5Mn1.5O4 with a cube space group of Fd3m. The results of scanning electron microscope (SEM) tests shows that the sample has a truncated octahedron structure with high crystallinity. Electrochemical tests display that the LiNi0.5Mn1.5O4 sample exhibits great electrochemical performance with a high reversible discharge capacity of 126.1 mAh g-1 at 0.5 C and excellent capacity retention of 92.8 % after 200 cycles. The superior performance of the synthesized sample is attributed to its appropriate proportions of {111} and {100} surfaces. It can achieve both high discharge capacity and good cyclic performance simultaneously.A truncated octahedron structure LiNi0.5Mn1.5O4 is prepared by solid-state method. The result of X-ray diffraction (XRD) indexed to the truncated octahedron structure of LiNi0.5Mn1.5O4 with a cube space group of Fd3m. The results of scanning electron microscope (SEM) tests shows that the sample has a truncated octahedron structure with high crystallinity. Electrochemical tests display that the LiNi0.5Mn1.5O4 sample exhibits great electrochemical performance with a high reversible discharge capacity of 126.1 mAh g-1 at 0.5 C and excellent capacity retention of 92.8 % after 200 cycles. The superior performance of the synthesized sample is attributed to its appropriate proportions of {111} and {100} surfaces. It can achieve both high discharge capacity and good cyclic performance simultaneously.

A citric acid assisted sol−gel method is employed for synthesizing Li1.2Mn0.54Ni0.13Co0.13O2 used as a cathode material in lithium-ion batteries. Powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) characterizations prove that materials have a typical a-NaFeO2 structure with primary nano−sized particles. Electrochemical performances have been investigated by charge-discharge test and results show that the synthesized product exhibits excellent electrochemical performance with a high initial discharge capacity of 253.5 mAh g-1 at 0.1 C and a preferable capacity retention of 84.8% after 50 cycles.

Al2O3 has successfully coated on LiNi0.6Co0.2Mn0.2O2 cathode material by a facile coating method. The results of scanning electron microscopy and transmission electron microscope images show that Al2O3 were successfully attached onto the surface of LiNi0.6Co0.2Mn0.2O2 as expected. Charge–discharge tests show that the Al2O3 coating LiNi0.6Co0.2Mn0.2O2 exhibits excellent electrochemical performance with a high initial discharge capacity of 180.2 mAh g-1 at 0.1 C and a high capacity retention of 95.2% after 100 cycles at room temperature under 1C. The superior performance of surface-modified LiNi0.6Co0.2Mn0.2O2 attributed to the uniform Al2O3 coating layer is expected to directly reduce the contact between the active cathode particles and electrolyte. Simultaneously, the uniform Al2O3 coating layer also improves structure stability and suppresses generation of oxygen.

This paper aims at improving the adhesive strength of SS 316L coating by substrate preheating (400, 600, and 700 °C). The relationships between the adhesive strength of coating/substrate interface and the substrate preheating temperature are discussed. It was found that stronger adhesion is able to occur despite the presence of a thick oxide film on the substrate surface. The preheated substrate surface undergoes a stronger plastic deformation that disrupts the oxide films for obtaining an intimate contact between particle and substrate material. In addition, the oxide films on the substrate surface can prevent the generation of material jet of the substrate. The effects of substrate preheating on the microstructure and hardness were also investigated.

Cold spray as a relatively new surface modification technique has great potential in the industry due to its ‘low working temperature’. The bonding quality between the cold-sprayed coating and the target substrate is one of the most important evaluation index for the coating performance. In this study, the interfacial bonding features between cold-sprayed Ni coatings and Cu are investigated to clarify the role of substrate temperature in the coating–substrate bonding. The finite element analysis model which can simulate the heat conduction through the coating–substrate interface is developed to model the particle deposition process on the substrate. The surface morphology and cross section of the experimentally deposited particles are observed by scanning electron microscope. The substrate surface oxidization behavior and coating–substrate interfacial atomic mixture are evaluated through the energy-dispersive spectroscopy line scans. The results indicate that heat conduction from the high-temperature substrate plays an important role in heating the interfacial region. The increased interfacial temperature significantly enhances the metallurgical bonding by improving the coating–substrate atomic mixture at the interface. Besides, the high-temperature substrate is also found to result in prominent metal jet and strong mechanical interlock due to the enhanced thermal softening effect. As a consequence, coating mass and coating–substrate bonding strength are promoted by using the high-temperature substrate.

The humidification tower is the key unit of a humid air turbine cycle. The compactness problem of a humidification tower is crucial to the flexibility and safe operation of the cycles. This research focuses on the potential application of the novel ceramic foam corrugated packing in humidification. The hydrodynamics and heat and mass transfer performances of this packing (type FSC-1) are investigated and compared with those of the traditional structured packing (type TJH-250). The experimental results show that the specific surface area obviously increases with a competitive voidage of 93% for ceramic foam corrugated packing. In comparison with THJ-250, FSC-1 exhibits about 60% pressure drop per mass transfer unit, 50% flooding gas velocity, and no more than 37% height of gas-phase mass transfer unit. Although the ceramic foam packing has relatively low air flux, it is also promising for the compact humidification tower due to its excellent heat and mass transfer performance and low pressure loss.

The effect of the substrate surface pretreatment on the Ni–Al interfacial bonding features in cold spray was investigated. Oxide-free interfacial area is found to be the essential factor that affects the interfacial atomic diffusion and metallurgical bonding. Voids are formed at the interface between the particle and grit-blasted substrates, significantly reducing the oxide-free interfacial area. However, those voids cannot be found at the interface between the particle and polished and ground substrates. Therefore, the polished and ground substrates can provide higher coating mass and coating-substrate bonding strength than the grit-blasted ones.

This paper considers agreement problems of networks of discrete-time agents with mixed dynamics and arbitrary bounded time delays, and networks consist of first-order agents and second-order agents. By using the properties of nonnegative matrices and model transformations, we derive sufficient conditions for stationary agreement of networks with bounded time delays. It is shown that stationary agreement can be achieved with arbitrary bounded time delays, if and only if fixed topology has a spanning tree and the union of the dynamically changing topologies has a spanning tree. Simulation results are also given to demonstrate the effectiveness of our theoretical results.

It is important to accurately predict the flow mode especially intertube falling-film mode of absorbent for its great impact on the heat and mass transfer in a horizontal tube absorber. In this paper, a test facility used to study falling-film outside horizontal tubes was built, and experiments were conducted to explore the intertube mode transitions with water-calcium chloride (CaCl2/water) solution in quiescent surroundings. The correlations which are more suitable for predicting CaCl2/water solution intertube mode transitions were developed. In general, the transitional Re will decrease with the solution concentration increasing, and its effects increase with the transitions from droplet mode to sheet mode. Hysteresis exists in all the mode transitions, and it is more obvious for low concentration solutions. The results may be an important support for modeling, designing and operating of CaCl2/water falling-film absorber.

This paper presents the hydrodynamic coefficient analysis for jack-up platform. Influencing factors of scale ratio, rack and incident angle are studied to explore the relations between the influencing factors and hydrodynamic coefficients. Wave tank test is introduced to carry out the hydrodynamic experiments. Test platform was set up in the wave flume, where wave and current load in different flow velocity, wave height and period combination can be simulated. Various experimental models are manufactured according to the influencing factors. The data was collected by using strain transducer and six-dimensional force sensor, which could measure the wave and current load. Based on Morison equation, hydrodynamic coefficients under different experimental conditions were obtained by analyzing the experiment data. Furthermore, the relationships between the influencing factors and hydrodynamic coefficient are discussed. Results show that scale ratio, rack and incident angle have great effect on the hydrodynamic characteristic for jack-up platform.

This paper aims to detect the structure damage in KT type jacket offshore platforms using acoustic emission analysis. Experimental investigation has been implemented to analyze the transmission characteristics, attenuation law, and source localization of the acoustic emission signals. The range of energy attenuation coefficient α and the signal amplitude attenuation law were obtained from experimental data. Hence, the layout of acoustic emission sensors was optimized based on the energy attenuation to achieve online damage monitoring for KT-jacket platforms. In order to validate the performance of the optimized sensor layout, another experimental test was conducted on the designed KT-jacket offshore platform to locate the acoustic emission sources. The test results demonstrate that a positioning error of 8 mm or below can be obtained using the optimized sensor layout, and the number of sensors can be reduced by 80% compared with that of the theoretical layout. As a result, the optimized sensor layout enables efficient and effective damage detection for KT-jacket offshore platforms.

The objective of this work is to study the thermodynamic mechanism and performance of an engine exhaust-powered adsorption refrigeration system using CaCl2 as adsorbent and NH3 as refrigerant. A 6 kW nominal refrigerating capacity adsorption refrigerator was developed. The working performance of the refrigerator is presented. It is concluded that the refrigerating capacity at constant evaporating temperatures varies with the input heat into the generator, and the heat transfer affects strongly the mass transfer in the adsorbent, making it work in different mean generation and adsorption temperatures. A conventional test bed was developed for investigating the properties of CaCl2–NH3 adsorption/desorption unit tube. A mathematical model based on non-equilibrium thermodynamics was developed to describe the performances of the adsorption refrigerating system.

The ball milling of Fe-24Mn and Fe-24Mn-6Si mixed powders has been performed by the high energy ball milling technique. By employing X-ray diffraction and Mossbauer measurements, the composition evolution during the milling process has been investigated. The results indicate the formation of paramagnetic Fe-Mn or Fe-Mn-Si alloys with a metastable fee phase as final products, which imply that the Fe and Mn proceed a co-diffusion mechanism through the surface of fragmented powders. The thermal stability and composition evolution of the as-milled alloys were discussed comparing with the bulk alloy. (C) 1999 Published by Elsevier Science S.A. All rights reserved.

Background: Enzymatic decolourization has been recently proposed as a promising and eco-friendly method for treatment of synthetic dye-contaminated wastewaters. However, the processes require large quantities of enzymes, attracting significant attention in developing efficient methods for mass production of multifunctional enzymes. Several methods such as response surface methodology (RSM) and orthogonal experiment have been applied to optimize the parameters in bioprocesses for enzyme production. Results: In the present study, a laccase-like enzyme, phenoxazinone synthase (PHS) originated from Streptomyces antibioticus was recombinantly expressed in Escherichia coli BL21 (DE3). The production of PHS in E. coli BL21 was optimized by response surface methodology based on Box-Behnken design. A full third-order polynomial model was generated by data analysis with Statistica 8.0 in which the optimal conditions for PHS production were calculated to be 1.525 mM CuSO 4 and 16.096 hrs induction at temperature of 29.88oC. The highest PHS production under optimal conditions was calculated to be 4098.51 U/l using the established model. Average PHS production obtained from actual production processes carried out under the calculated optimal conditions was 4052.00 U/l, very close to the value predicted by the model. Crude PHS was subsequently tested in Congo red decolorization which exhibited a low decolourization rate of 27% without mediator. Several mediators were found to improve PHS-catalyzed Congo red decolourization, with the highest rate of 73.89% obtained with 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) as mediator under optimized conditions of 4000 U/l PHS activity, 10 µM ABTS, 100 µM Congo red, and 8 hrs reaction time. Conclusion: Our results indicated that PHS recombinantly produced in E. coli BL21 was a prospective enzyme for decolorizing reactive dye Congo red.

Rubber mixing is an important production process in the tire plant, and the control of discharge point, which is the most important action point, is seriously relevant with the final tire quality. This paper presents a SVM (support vector machine) discharge modeling method based on statistical learning theory (SLT) to treat the limitation of conventional methods. Abnormal modeling samples are first divided into three different types according to the input and output distribution properties, and corresponding approaches are developed to eliminate the outliers, respectively. Then SVM technique is applied to build the discharge model to establish the rubber discharge condition. The obtained model was applied to a pilot plant of the Hangzhou Zhongce Rubber Co. Ltd., China and the result shows that the proposed method suffices the demand of data-driven modeling in finite-sample, complexity control and robustness of actual mixing process, and the discharge modeling method is valid.

Background: Previous studies have reported telaprevir is effective for chronic hepatitis C virus infection, but the safety of a telaprevir-based regimen remains uncertain. Objective: A meta-analysis was performed to assess the safety of the addition of telaprevir to a standard regimen of pegylated interferon (peginterferon) plus ribavirin (combination telaprevir with peginterferon plus ribavirin, the TPR group) compared with the standard regimen group (peginterferon plus ribavirin, the PR group). Methods and Results: Seven randomized controlled trials involving a total of 2808 patients were included in the meta-analysis. The addition of telaprevir to the standard regimen was associated with a significantly increased risk of serious adverse events compared with the standard PR group (relative risk [RR]=1.56; 95% confidence interval [CI] 1.21, 2.03; p = 0.0007; I2 = 0%). Telaprevir was also associated with increased risk of treatment discontinuation (RR = 2.10; 95% CI 1.56, 2.83; p