Strictly nonblocking directional-coupler-based switching networksunder crosstalk constraint

Directional-coupler (DC)-based switching systems can switch signals at the rate of several terabits per second. Such switches can also transmit signals with multiple wavelengths simultaneously. Despite these advantages, DCs suffer from an intrinsic crosstalk problem that must be overcome in building a robust switching system. In this paper, the principles of constructing strictly nonblocking DC-based photonic switching systems under various crosstalk constraints are explored. We demonstrate how crosstalk adds a new dimension to the theory of switching systems. We find the sufficient nonblocking condition for photonic networks under crosstalk constraints and demonstrate that some well-known nonblocking networks can tolerate a stricter crosstalk constraint while retaining their hardware complexity. The theory developed in the paper can guide us in making the design tradeoff between the level of crosstalk and the amount of hardware     

A/I Net: a network that integrates ATM and IP

Future networks need both connectionless and connection-oriented services. IP and ATM are major examples of the two types. Connectionless IP is more efficient for browsing, e-mail, and other non-real-time services; but for services demanding quality and real-time delivery, connection-oriented ATM is a much better candidate. Given the popularity of the Internet and the established status of ATM as the broadband transport standard, it is unlikely that one can replace the other. Therefore, the challenge we face lies in finding an efficient way to integrate the two. This article describes a research project reflecting this trend. The project aims at efficient integration of the two to eliminate the deficiencies of a standalone ATM or IP network     

A modified Hull cell with forced electrolyte flow: simulation of industrial electroplating conditions

Hull cells are often used to determine the optimum current density range for industrial electroplating. However, these cells do not reproduce correctly the hydrodynamic conditions. The design and the use of a modified Hull cell able to reproduce constant hydrodynamic conditions at the cathode for a large range of circulation speeds are described. Mass transfer and current distribution at the cathode have been evaluated in this cell for copper and zinc deposition.     

Structural and dimensional stabilities of tin-bismuth fusible cores

Eutectic tin-bismuth alloys, used as fusible cores for high polymer injection moulding, were studied in order to identify structural and dimensional modifications during ageing at temperatures ranging from 4 to 110°C. Optical and scanning electron microscopies together with X-ray diffraction were used to observe the coarsening of the eutectic structure and to plot an isothermal transformation diagram. Thermal cycles around the eutectic temperature promoted the dissociation of the eutectic structure into light tin dendrites at the top of the ingots and heavy bismuth crystals at the bottom. Differential scanning calorimetry and thermomechanical analysis were performed to observe possible phase transformations.     

Physiological, volatile, and SEM surface effects resulting from cutting and dipping treatments in cantaloupe

Previous research examined sanitation treatments on cut cantaloupe tissue to deliver germicidal and food safety effects. However, an apparent compromise between volatile loss and treatment/sampling efficacy appeared. Subsequently, a physiological and volatile reassessment of thinly sliced tissue against cubes was performed in cantaloupe tissue. Thin sliced cantaloupe L* decreased 27.5%, 40.5%, and 52.9% in 3, 2, and 1 mm thickness, respectively, compared with cut cubes after 3 d. Overall color (C) decreased in freshly prepared cubes (2.4%) and slices (14.4%) that were washed in cold water. Surface area per unit volume (SA: vol) in slices was 4.1 times greater than typical cubes, as reflected by substantial water loss (20.4%, 9.5%, and 6.7% in 1, 2 and 3-mm slices, respectively) after 1 d at 5 °C. Rinsing cubes and thin-slices with 5 °C deionized water resulted in roughly 15% soluble solids loss. SEM indicated 65.4% reduced cell size in 1-d old thin slices, evidenced by excessive cell damage and desiccation compared with stored fresh-cut cubes. In thin-sliced tissue exposed 15 min to an open atmosphere (mimic sanitation treatments), total esters decreased 92.8% and 95.8%, respectively, after 1 and 3 d storage at 5 °C. Washing tissue provided a boundary layer that reduced short-term ester losses in slices and cubes. Excessive cutting, sanitation treatment regimes, and storage can radically alter the desirable volatile profile of cut cantaloupe. Reduction of tissue size to maximize food-safety sanitation efficacy or delivering items to a niche market will need substantial work to engineer equipment and develop protocols to insure that product quality and volatiles are not compromised. PRACTICAL APPLICATION: We have demonstrated that cutting method and sampling protocol are critically important when using volatiles as a means by which to assess or interpret stress response and ascribe fresh-cut quality. Reduction of tissue size to maximize food-safety sanitation efficacy (for example, thin slices) will need substantial work to engineer equipment and design protocols to insure product quality and volatile profiles are not compromised.     

Routing and time-slot assignment in optical TDM networks

Optical time-division multiplexing (O-TDM) networks can provide a finer bandwidth granularity than wavelength-division multiplexing networks, and will play an important role in future all-optical networks. Since optical buffers are expensive, a small buffer size will be the characteristic of O-TDM systems. This paper analyzes the problem of routing and time-slot assignment in O-TDM networks. The results lead to the proposal of a Dijkstra-like shortest-path routing scheme that intends to maximize the performance of an optical network with a small number of optical buffers. Performance evaluation of the proposed scheme is also presented.     

Solubilities,densities and electrical conductivities of aqueous copper(I) and copper(II) chlorides in solutions containing other chlorides such as iron,zinc, sodium and hydrogen chlorides

With a view to industrial applications, solubilities, densities and electrical conductivities of aqueous copper(I) and copper(II) chlorides were measured in solutions containing other chlorides like those of iron, zinc, sodium and hydrogen.In these solutions copper(I) chloride shows a behaviour similar to that observed in pure CuClNaClHCl solutions. Increasing the FeCl₂ concentration decreases the solubility of CuCl less than increasing the ZnCl₂ concentrations does. Moreover, increasing total Cl^? concentration increases CuCl solubility if Cl^? is added as FeCl₂ and decreases CuCl solubility if Cl^? is added as ZnCl₂. NaCl solubility remains unchanged by FeCl₂ additions and is increased by ZnCl₂ additions.Copper(II) chloride also shows in these solutions a behaviour similar to that observed in pure CuCl₂NaClHCl solutions. FeCl₃ additions decrease CuCl₂ · 2 H₂O solubility in a more drastic manner than ZnCl₂ additions. However, NaCl additions have a much higher effect.These results can be qualitatively interpreted when taking into account the relative Cl^? donor or acceptor character of the constituent chloride salts of the solution.FeCl₂ additions slightly decrease the electrical conductivity of Cu(I) solutions. However, this can easily be compensated by a slight increase in temperature or in acidity.     

Effect of instructions and modeling on trainees low in interpersonal-communication skills.

Examined the effects of instructions and modeling in the reflection-of-feeling training of individuals low in interpersonal-communication skills. Participants with low scores on R. Carkhuff's Communication Index (25 males and 25 females) were randomly assigned by sex to 1 of the 5 training groups so that there were 5 males and 5 females in each group. After viewing videotaped training material, each participant conducted a 15-min interview with a volunteer "client" and completed the Communication Index a second time. Interviews were scored for frequency of reflection-of-feeling responses and level of empathic communication displayed. Analysis of the reflection-of-feeling data indicated that instructions and instructions-plus-modeling were facilitative procedures. Ratings of written and verbal empathy demonstrated the effectiveness of the 2 combined conditions: instructions-plus-modeling and modeling-plus-instructions. Calculation of correlations among scores on criterion measures revealed a positive correlation between reflection-of-feeling scores and ratings of empathic communication. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Design for a high-speed m.o.s. associative memory

An experimental 64-bit m.o.s. associative memory has been developed from a limit-case design study. Speeds in excess of 50 MHz are reported at a cost per bit that could approach eight times that for a conventional m.o.s. dynamic r.a.m. The design of the basic associative memory cell is described.