Influence of Lubricant on the Nucleate Boiling Heat Transfer Performance of Refrigerant—A Review

This review provides an overview of the lubricant on the heat transfer performance pertaining to nucleate boiling. It appears that the effect of individual parameter on the heat transfer coefficient may be different from study to study. This is associated with the complex nature of lubricant and some compound effects accompanying the heat transport process. Some important effects such as oil concentration, heat flux, geometric configuration, saturation temperature, thermodynamic and transport properties, miscibility, foaming, and additional surface active agent are reported and discussed. In general, the heat transfer coefficient is impaired provided the oil concentration is sufficient high (e.g., >7%), and this is applicable to smooth and structured tubes. But normally structured tubes tend to suffer more from lubricant, yet this is especially conspicuous when the size of the reentrant channel is small. On the other hand, foaming and partial miscibility seem to benefit the heat transfer coefficient.     

Production of glass–ceramics from incinerator ash using lab-scale and pilot-scale thermal plasma systems

This research employed two thermal plasma melting systems and vitrification technology to treat incinerator ash. The melted slag was used for the production of glass–ceramics via powder sintering and heat treatment. When using the pilot-scale plasma molten system, the melt was rapidly quenched in water to yield glassy slag. The properties of quenched slag glass–ceramics were superior to that glass–ceramics produced by slowly cooling the slag with air. The glass–ceramics with the best physical/mechanical properties and chemical resistance was produced by heat treatment at 1150 °C for 2 h. Diopside and gehlenite were formed as the major crystalline phases. Glass–ceramics produced from incinerator ash demonstrate great potential for reutilization as non-porous or water permeable materials.     

Adaptive blind receivers for MC‐CDMA communication systems

In this paper, we propose three adaptive blind algorithms for multiuser multicarrier code division multiple‐access systems in multipath fading channels. The proposed adaptive blind receivers are based on the property of the discreteness of the input data symbol and are updated in every symbol interval. We also use the concept that the variance of the output signal approaches to the variance of the desired signal to get the cost function. The three proposed receiver structures are the traditional finite impulse response (FIR) structure, the despreading (DES) filter structure and the generalized sidelobe canceller (GSC) structure. The advantage of the FIR filter is that the length of the filter weights does not have to be the same length as the spreading code. For the DES filter, the combination of the adaptive weight and the despreading code has the simplest structure than the other two proposed receiver structures. The constrained GSC filter is superior to the other two proposed receiver structures in the environments dominated by multiple‐access interference. By this constraint, the blind GSC filter can guarantee to converge to the desired solution. Simulation results are given to show the effectiveness and comparison of the proposed adaptive blind receivers. Copyright © 2012 John Wiley & Sons, Ltd.     

Interblock memory for turbo coding

We investigate a binary code, which is implemented by serially concatenating a multiplexer, a multilevel delay processor, and a signal mapper to a binary turbo encoder. To achieve improved convergence behavior, we modify the binary code by passing only a fraction of the bits in the turbo code through the multilevel delay processor and the signal mapper. Two decoding methods are discussed and their performances are evaluated.     

G2 Continuity for Multiple Surfaces Fitting

Fitting 3D known data into sculptured surfaces has received extensive attention. However, most algorithms available are suitable only for an isolated surface. A part typically contains multiple surface regions that must be blended to a degree of continuity. The conventional approach based on blending, lofting, stitching, etc. cannot guarantee the quality of the surface near the jointed area. The purpose of this work is to present a surface-fitting algorithm for multiple sets of data, concentrating on G 2 continuity across the boundary of the fitted surfaces. The proposed surface-fitting algorithm essentially fits several sets of data simultaneously, and yields a B-spline surface for each set of data. The G 0 ,G 1 , and G 2 continuity conditions between B-spline surface patches were addressed. Based on these results, additional constraints were specified to achieve G 2 continuity across the surface boundary. A successful demonstration of the proposed strategy is provided also.     

Adaptive DS-CDMA Receiver with Code Tracking in Phase Unknown Environments

In this paper, we propose and analyze a new noncoherent receiver with PN code tracking for direct sequence code division multiple access (DS-CDMA) communication systems in multipath channels. We employ the decision-feedback differential detection method to detect MDPSK signals. An ";error signal"; is used to update the tap weights and the estimated code delay. Increasing the number of feedback symbols can improve the performance of the proposed noncoherent receiver. For an infinite number of feedback symbols, the optimum weight can be derived analytically, and the performance of the proposed noncoherent receiver approaches to that of the conventional coherent receiver. Simulations show good agreement with the theoretical derivation.     

Complex time series from a modulated semiconductor laser: itsdeterminism exploration

A singular value decomposition (SVD) eigenvalue spectrum is employed to explore the deterministic nature of the complex time series from a modulated semiconductor laser. With this method, the signature of chaos can be quickly identified and the noise contamination ratio can also be estimated. Relations between the supplied modulation of laser diode and the noise level are illustrated. The connection between relative intensity noise and the noise floor in the SVD spectrum has also been clarified     

Proximate composition, total phenolic content, and antioxidant activity of seagrape (Caulerpa lentillifera)

The proximate composition of seagrape (Caulerpa lentillifera) from culture ponds in Penghu, Taiwan was analyzed. The phenolic content and the antioxidant activities including the 1,1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging activity, ferric ion-reducing activity, hydrogen peroxide scavenging activity, and ferrous ion chelating (FIC) activity of the ethanolic extracts of dry seagrape samples using 2 drying methods of freeze drying and thermal drying were compared with the ethanolic extract of Oolong tea as a reference. The contents (dry weight basis) of carbohydrate, crude protein, crude lipid, crude fiber, and ash of seagrape obtained from culture ponds in Taiwan were 64.00%, 9.26%, 1.57%, 2.97%, and 22.20%, respectively. The total phenolic content (1.30 mg gallic acid equivalent [GAE]/g dry weight) of the ethanolic extract of thermally dried seagrape was significantly lower (P < 0.05) than that (2.04 mg GAE/g dry weight) of freeze-dried seagrape, and both were significantly lower than that (13.58 mg GAE/g dry weight) of Oolong tea. At the same phenolic content, the antioxidant activities of freeze-dried seagrape were significantly higher (P < 0.05) than those of thermally dried seagrape. Compared with Oolong tea, seagrape, irrespective of drying method used, generally had strong hydrogen peroxide scavenging activity; but it was weak in DPPH radical scavenging activity, ferric ion-reducing activity, and FIC activity. The antioxidant activity of seagrape and Oolong tea was significantly influenced by their phenolic contents. PRACTICAL APPLICATION: The proximate composition, total phenolic content, and antioxidant activity of seagrape (Caulerpa lentillifera) in Taiwan were determined in this research to indicate nutritionally of this edible seaweed to human health, and compared these results to previous studies.     

A ship motion simulation system

In this article, efficient computational models for ship motions are presented. These models are used to simulate ship movements in real time. Compared with traditional approaches, our method possesses the ability to cope with different ship shapes, engines, and sea conditions without the loss of efficiency. Based on our models, we create a ship motion simulation system for both entertainment and educational applications. Our system assists users to learn the motions of a ship encountering waves, currents, and winds. Users can adjust engine powers, rudders, and other ship facilities via a graphical user interface to create their own ship models. They can also change the environment by altering wave frequencies, wave amplitudes, wave directions, currents, and winds. Therefore, numerous combinations of ships and the environment are generated and the learning becomes more amusing. In our system, a ship is treated as a rigid body floating on the sea surface. Its motions compose of 6 degrees of freedom: pitch, heave, roll, surge, sway, and yaw. These motions are divided into two categories. The first three movements are induced by sea waves, and the last three ones are caused by propellers, rudders, currents, and winds. Based on Newton’s laws and other basic physics motion models, we deduce algorithms to compute the magnitudes of the motions. Our methods can be carried out in real time and possess high fidelity. According to ship theory, the net effects of external forces on the ship hull depend on the ship shape. Therefore, the behaviors of the ship are influenced by its shape. To enhance our physics models, we classify ships into three basic types. They are flat ships, thin ships, and slender ships. Each type of ship is associated with some predefined parameters to specify their characteristics. Users can tune ship behaviors by varying the parameters even though they have only a little knowledge of ship theory.