Ultrasonic‐assisted dyeing: I. Nylon dyeability with reactive dyes

The use of ultrasonic power (38.5 KHz, 350 W) to assist the dyeability of nylon‐6 fibre with reactive dyes is reported. The effects of the different factors that may affect the dyeability of nylon‐6 fibre with Reactive Red 55 were simultaneously carried out under both ultrasonic power and conventional heating conditions. The colour strength values obtained for the dyed samples using ultrasonic power were higher than those obtained using conventional heating. Also, the effect of alkaline soaping treatment on dye fixation for the dyed fabrics with different reactive dyes, at both acidic and neutral pHs, is generally better with ultrasonic than with conventional heating. The overall results indicate that the enhancing effect is mainly attributed to the de‐aggregation of dye molecules, which leads to better dye diffusion and possible assistance for dye‐fibre covalent‐bond fixation. The results of wet fastness properties of the dyed fabrics reveal improvement using ultrasonic power dyeing relative to the conventional heating method. © 2003 Society of Chemical Industry     

Surface voltages and resistance of grounding systems of grid androds in two-layer earth by the rapid Galerkin's moment method

The point matching moment method has been the prime candidate for grounding system analysis. The regular method yields accurate results as long as the segmentation is very fine. This means a large number of basis functions and frequently requires a super computer. In the present paper, we propose an alternate moment method in the Galerkin's form. This form is variational (i.e. with error reduction property) which allows for very few basis functions, resulting in a very fast convergence but still gives less than 2% error in the grounding resistance. Each basis function in this form can be a whole rod with uniform current distribution, representing a vertical driven rod or a horizontal rod across a whole grid. Such basis functions give good results in the grounding resistance, it is obvious that they need not give good results in the voltages (ground potential rise, touch, and step) on the earth surface near the grid intersections. To correct this, a second type of basis functions namely spheres is added at the intersections. Since the intersections are few, the total number of basis functions is still small. With such basis functions added, however, the resulting voltages now have errors generally less than 4%. With such high accuracy and small matrix size (≈10×10 to 50×50) in the moment method it is easy to do parametric studies, even for an extensive grounding system     

Hybrid Schottky injection MOS-gated power transistor

A modified Schottky injection field effect transistor (SINFET) which offers lower on-resistance and a switching speed comparable to conventional n-channel LDMOSTs is described. The fabrication process is similar to that of an LDMOS transistor but with the high-low (n+n-) `ohmic? contact at the drain replaced by a parallel combination of a Schottky barrier and a pn junction diode. This hybrid anode injects minority carriers into the n- drift region, which in turn provides conductivity modulation. A current handling capability 3.5 times larger than that of the LDMOST is achieved. With the minority carrier injection level limited by the Schottky barrier, the total amount of minority carriers injected by the hybrid anode is much lower than that injected by the pn junction diode alone. Thus, the device speed is comparable to the conventional n-channel LDMOST. By minimising the shunting resistance in the p-channel region, devices with a latch-up current density of 400 A/cm2 are obtained.     

Resistance formulas of grounding systems in two-layer earth

This paper lists, under one umbrella, the resistance formulae of power network grounding systems, namely: the buried grid; the driven rodbed; and the combination of the buried grid and rodbed. The formulae are synthesized from rigorous asymptotes; as a result, they are accurate (averaged error ≈5%) and do not require empirical tables or graphs. The validity of these formulae is verified in this paper, not by their derivations, since they are too lengthy, but by checking numerically, against the results of detailed-numerical methods and analytically, against asymptotes. The formulae are suitable for calculation with a handheld calculator, and therefore they are useful tools for an engineer in the field     

Design of a 1.5 V full-swing bootstrapped BiCMOS logic circuit

A low voltage full-swing BiCMOS bootstrapping technique that allows the design of BiCMOS logic circuits at supply voltages down to 1.5 V is presented. This is the first 1.5-V design technique that does not require complementary bipolar devices. The technique is shown to have significant advantages over existing low voltage BiCMOS logic designs in sub-3 V operation. Inverter gates fabricated using a 0.8-μm technology were operated at 150 MHz with a supply voltage of 1.5 V. Implementation of this technique on dynamic logic is also demonstrated and experimental results match closely with simulation     

Effect of wheel speed on the tracking time in a rotatingwheel-spray tracking test

A low speed rotating wheel spray test procedure for insulation is described and typical results are presented on a number of low tracking resistance polymers. It is found that the time to tracking is a monotonically increasing function of the wheel speed at low speeds of up to 2.0 RPM. This reverse behavior of what normally occurs at high wheel speeds is explained in terms of residence times of the specimen in the water spray and in the air as a function of the speed     

Decay of HIV-1 DNA in patients receiving suppressive antiretroviral therapy

HLA-B27 is associated with the etiology of ankylosing spondylitis (AS) and acute anterior uveitis (AAU). Transporter associated with antigen processing (TAP) 1 and TAP2 polymorphism influences the range of peptide presented by HLA class I molecules. In this report, contribution of TAP polymorphism to the susceptibility to AS and AAU was studied in HLA-B27-positive Japanese individuals. Patients were classified into three groups: 16 AS patients, 14 AAU patients and 22 patients with both AS and AAU. Twelve HLA-B27-positive healthy individuals were included as a control. TAP polymorphism was detected by PCR-RFLP methods. Significant differences in frequencies of TAP1 alleles were not found between patient groups. None of the TAP2 frequencies showed increased or decreased frequencies compared with HLA-B27-positive healthy controls. In comparison with a random Japanese control, TAP2D allele frequency was significantly increased in the AAU group, but failed to reach a significant level in a group consisting of the AAU-only patients and the patients with both AS and AAU. All of the patient groups were noted to have a significantly increased prevalence of the TAP2H allele as compared to random controls; however, the higher frequency of this allele was detected in HLA-B27 healthy controls as well. These observations suggest a linkage disequilibrium between TAP2D, TAP2H and HLA-B27 in Japanese.     

Design of earthen vegetated open channels

Modified formulas for Manning's equation are developed for use in the design of earthen open channels with submerged aquatic weeds. The proposed relations have their basis in field and experimental data. A multiple regression analysis was used to develop a relationship between the mean velocity, hydraulic radius, and water surface slope. The new formulas are dependent on the distribution of weeds along the channel's wetted perimeter and the percentage of vegetation density with respect to the cross-section area of the waterway.Notation A cross-section area - A _w area of weeds - B ₁ top width of channel flow - g acceleration of gravity - h height of roughness element - n Manning's coefficient - Q discharge of flow - R hydraulic radius - S water surface slope - S ₀ bed surface slope - V mean flow velocity     

High-resolution, current-mode A/D convertors using active currentmirrors

An improved current-mode algorithmic A/D convertor (ADC), using active current mirrors, is described. These mirrors eliminate current mismatches due to the transistor's finite output resistance, allowing the construction of higher-resolution ADCs than is possible using simple current mirrors