A tandem approach to selection of machinability data

One drawback of current machinability data systems is the inability to accommodate technological changes. Existing schemes to optimise machinability data are too specific and rigid. This paper describes the development of a methodology for a more effective selection of machinability data. The methodology incorporates various techniques, such as expert systems and mathematical programming. The unique feature of this system is the way machinability data are handled to arrive at the most suitable solution. The system accepts a wide range of data, from the very complete and specific to the very general. The more detailed and specific the data set is, the more credible the results will be. The machinability data in the data banks are easily updated and improved using feedback data from current shop floor production. The process of obtaining solutions from these banks is regarded as flexible optimisation. This paper reports on the optimisation methodology for multipass turning operations. Longitudinal turning, facing, taper turning and contour turning have been considered.     

Parental handedness and relative hand skill: A test of the developmental instability hypothesis.

In previous studies (e.g, R. A. Yeo et al; see record 1993-40422-001), both left-handers and extreme right-handers showed evidence of increased developmental instability, as indexed by minor physical anomalies and by specific fluctuating anatomic asymmetries. Thus, developmental instability may be an important factor affecting handedness. In the present study, a specific prediction of the developmental instability model of handedness, one that distinguishes it from the single-gene models of M. Annett (1985) and I. C. McManus (see record 1986-21280-001), was tested among 225 undergraduates. The model suggests that the degree of deviation from modal handedness, rather than direction of handedness, is heritable. Thus, it was hypothesized that extreme right-handers as well as left-handers have an elevated proportion of left-handed parents. Results supported this hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A minimal avian retroviral packaging sequence has a complex structure

We have defined a 160-nucleotide region, Mpsi, from the 5' leader region of the Rous sarcoma virus genome that is sufficient to direct the packaging of a heterologous RNA. Mpsi contains the putative O3 stem structure that has previously been shown, and that has been confirmed in this study, to be important for the efficient packaging of avian leukosis-sarcoma virus RNA. Analyses of several O3 stem mutants revealed that other regions within Mpsi can interfere with the proper folding of altered sequences which are predicted to form a wild-type O3 stem.     

Design and Optimization of the Extended True Single-Phase Clock-Based Prescaler

The power consumption and operating frequency of the extended true single-phase clock (E-TSPC)-based frequency divider is investigated. The short-circuit power and the switching power in the E-TSPC-based divider are calculated and simulated. A low-power divide-by-2/3 unit of a prescaler is proposed and implemented using a CMOS technology. Compared with the existing design, a 25% reduction of power consumption is achieved. A divide-by-8/9 dual-modulus prescaler implemented with this divide-by-2/3 unit using a 0.18-mum CMOS process is capable of operating up to 4 GHz with a low-power consumption. The prescaler is implemented in low-power high-resolution frequency dividers for wireless local area network applications     

E-mode cutoff wave number of circular waveguide loaded with dielectric sector

The E-mode cutoff wave numbers of circular waveguide loaded with dielectric sectors were evaluated theoretically using the null-field formulation. These values are found to agree closely with cutoff wave numbers measured by using the transverse resonance technique.<>     

Chromatographic analysis of ceramide III ofSaccharomyces cerevisiae

Ceramide was prepared by the cultivation ofSaccharomyces cerevisiae from cell extracts by solvent exfraction and analyzed by NP-HPLC using a UV detector. The mobile phase was composed of hexane, methanol, and IPA. From the experimental conditions, the composition of mobile phase was 72/5/23 (hexane/IPA/methanol, vol%). Quantitative analysis of ceramide was performed. Based on the analytical conditions, the effect of cultivation temperature for the production of ceramide was investigated and the optimum cultivation temperature was found to be 35°C. This paper is dedicated to Dr. Youn Yong Lee on the occasion of his retirement from Korea Institute of Science and Technology.     

Rubber elasticity of poly(n-butyl acrylate) networks formed with multifunctional crosslinkers

The rubber elasticity characteristics of poly(n-butyl acrylate) networks crosslinked with tetrafunctional (EGDM and TEGDM), hexafunctional (TMPTM), and octafunctional (PETMA) vinyl crosslinkers were investigated. Both gel—sol analyses and crosslinking efficiency theories were used to evaluate the chemical crosslink contribution v_c and the entanglement contribution v_p to the elastically effective network chains v_e, and the effect of the crosslink junction functionality f on the front factor g. The front factors obtained were in the range of 0.50–0.92, depending upon the network system and the counting method for v_c. The relationship of g = [(f ? 2)/f]/〈r²〉/〈r²〉_o seems reasonable in the case of the tetrafunctional and hexafunctional networks, but deviates in the case of the octafunctional network. It is also evident that the functionality scheme for the front factor could only be valid under the postulate of a high v_p, which increases with increasing v_c, especially in the high v_c region near the Gaussian limit. The average energetic contribution to the retractive force of the present systems, expressed as F_e/F, is ?0.30 ± 0.1.     

10 Gb/s Linear Full-Rate CMOS Phase Detector for Clock Data Recovery Circuit

An improved linear full-rate CMOS 10 Gb/s phase detector is proposed. The improved phase detector overcomes the difficulties in realizing the full-rate operation by adding an I/Q splitter for the input data. Such a topology enlarges the pulse width of output signals to ease the full clock rate operation and the problem of the half period skew in the whole clock data recovery system. The proposed topology is able to provide a good linearity over a wider operating range of input phase offset compared to that of existing designs. The phase detector using the Chartered 0.18 μ m CMOS process is capable of operating up to a 10 GHz clock rate and 10 Gb/s input data for a 1.8 V supply voltage with 31 mW power consumption.