On some sets of difference sequences of fuzzy numbers

In this paper we define the sequence space w_F(f,p,\Updelta){w}_{{\mathcal{F}}}\left(f,p,\Updelta\right) which is called the space of strongly \Updelta p\Updelta p-Cesàro summable sequences with modulus f. Furthermore the fuzzy Δ-statistically pre-Cauchy sequence is defined and the necessary and sufficient conditions are given for a sequence of fuzzy numbers to be fuzzy \Updelta\Updelta-statistically pre-Cauchy and to be fuzzy \Updelta\Updelta-statistically convergent. Also some relations between w_F(f,p,\Updelta)w_{{\mathcal{F}}}(f,p,\Updelta) and S_F(\Updelta){S}_{{\mathcal{F}}}(\Updelta) are given.     

A Current-Mode Logic for Low-Voltage, High-Speed Mixed-Mode VLSI Circuits

A wired-AND current-mode logic (WCML) circuit is designed for high performance mixed analog and digital system designs on a common silicon substrate, using standard CMOS process. Current is used for digital information carrier in order to be able to reduce supply voltage, power consumption, digital switching noise and to increase operating frequency. The WCML circuit uses current-steering technique. It is composed of a simple current mirror with a current injector. Wired-AND connections cause the logic circuit to operate as a NAND logic gate which provides to implement any boolean function. High-speed is achieved by varying the injection current level even at low-voltage supply (<1.5 V) with low-power consumption.     

Diffusion bonding of investment cast γ-TiAl

Intensive alloy development studies on intermetallic gamma () based alloys in recent years has led to the development of several aerospace engine components using advanced -TiAl based alloys by ingot and powder metallurgical routes. These materials are of great interest to the aerospace industry owing to their very low density and good high temperature properties. Further application of this material will require the development of successful joining and cost effective fabrication methods. Joining of this intermetallic alloy by fusion joining processes, however, requires very careful process controlling, i.e. low cooling rates and very high preheat temperatures. On the other hand, solid state joining processes, particularly diffusion bonding, brazing, and friction welding, can readily be used to join this material. In the present work, successful application of solid state diffusion bonding to weld investment cast -TiAl alloys has been demonstrated. A series of diffusion bonds were produced without using an interlayer at temperatures ranging from 950 to 1100°C with different pressure levels and holding times. Bonds have been characterized using optical and scanning electron microscopy. Defect-free bonds were achieved for all the conditions studied. The bond qualities were assessed by shear testing at room temperature. Reasonable shear strength levels were obtained by bonding at 1000 and 1100°C for 3 h at pressures of 20 and 40 MPa, respectively. The bonds were also post bond heat treated at 1430°C for 30 min, which improved the bond quality in all cases.     

Quantitative Measurements of the Influence of Participant Roles during Peer Review Meetings

Peer review meetings (PRMs) are formal meetings during which peers systematically analyze artifacts to improve their quality and report on non-conformities. This paper presents an approach based on protocol analysis for quantifying the influence of participant roles during PRMs. Three views are used to characterize the seven defined participant roles. The project view defines three roles: supervisor, procedure expert and developer. The meeting view defines two roles: author and reviewer, and the task view defines the roles reflecting direct and indirect interest in the artifact under review. The analysis, based on log-linear modeling, shows that review activities have different patterns, depending on their focus: form or content. The influence of each role is analyzed with respect to this focus. Interpretation of the quantitative data leads to the suggestion that PRMs could be improved by creating three different types of reviews, each of which collects together specific roles: form review, cognitive synchronization review and content review.     

Production of hydrogen over bimetallic Pt–Ni/δ-Al2O3: II. Indirect partial oxidation of LPG

Indirect partial oxidation (IPOX) of a 75:25 propane:n-butane mixture, which was used as a model for LPG, was studied over the bimetallic 0.2 wt%Pt–15 wt%Ni/δ-Al₂O₃ catalyst in 623–743 K temperature range. The effects of steam to carbon ratio (S/C), carbon to oxygen ratio(C/O₂) and residence time (W/F (g cat-h/mol LPG)) on the hydrogen production activity, selectivity and product distribution were studied in detail. The results are compared with the results obtained in the IPOX of pure propane. An Increasing Temperature Program (ITP) was applied during all experiments and the results showed that the presence of n-butane in the feed enhances hydrogen production activity and selectivity. Considering the well established distribution network of LPG and the superior performance of the bimetallic Pt–Ni catalyst in the IPOX of LPG, Pt–Ni system seems a very promising catalyst alternative to be used in commercial fuel processors.     

Non-Gaussian elasticity of poly(2-acrylamido-2-methylpropane sulfonic acid) gels

Summary A series of strong polyelectrolyte hydrogels was prepared from the sodium salt of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) as the monomer and N,N-methylene(bis)acrylamide (BAAm) as a crosslinker. The hydrogels prepared between 9 and 50 mol % BAAm appeared homogeneous to eye but exhibited large spatial fluctuations of polymer concentration, as determined by the light scattering measurements. The elasticity tests show that the modulus of elasticity of gels increases with increasing degree of swelling, starting from the gel preparation state. Thus, the mechanical properties of the hydrogels are improved on their swelling in water. It was shown that the hydrogels even at a gel state just after their preparation are in the non-Gaussian regime due to the high degree of spatial gel inhomogeneity.     

Projection display for the generation of two orthogonal polarized images using liquid crystal on silicon panels and light emitting diodes

We present a projection system that is capable of two-dimensional and three-dimensional image display. A novel projection architecture is discussed that can simultaneously generate two linear polarized full-color images with orthogonal states of polarization using only one optical system. Both images are modulated by using two high-resolution liquid crystal on silicon panels that are illuminated with high-power light emitting diodes. The optical core and the illumination system are simulated, characterized, and optimized with nonsequential ray tracing software. A proof-of-concept demonstrator of the entire projection system is built and characterized. Important component specifications are discussed to improve the system performance.     

On estimating Weibull modulus by moments and maximum likelihood methods

The effect of true Weibull modulus and sample size on Weibull modulus estimated by moments and maximum likelihood methods was investigated. Results indicated that the value of true Weibull modulus had no effect on estimated modulus for the maximum likelihood method, and a strong effect for the moments method, especially when sample size was less than 30. In addition, the distribution of Weibull modulus estimated by both methods was investigated using the modified Anderson–Darling statistics for goodness of fit. It was found that the distribution was not normal, lognormal, 3-parameter Weibull, or 3-parameter log-Weibull for the maximum likelihood method, as reported in previous studies. For the moments method however, the distribution of normalized Weibull moduli was found to be lognormal for sample sizes of 40 and above. The other three distributions showed a significant level of lack-of-fit at all sample sizes. An erratum to this article can be found at