Comments on "Combined turbo codes and interleaver design"

The authors comment that in the paper of Yuan, Vucetic and Feng (see ibid., vol.47, p.484-87, Apr. 1999), the optimum distance spectrum (ODS) code found for memory order v=5, is actually v=3 convolutional code. The ODS code with h/sub 0/=43/sub s/ and h /sub 1/=55/sub s/ is actually v=3 code, because the feedback polynomial h/sub 0/, and feedforward polynomial h/sub 1/ are not relatively prime polynomials.     

Chemical injection to prevent building damage induced by ground water drainage from shallow tunnels

Progressive developments in the application of chemical injection have been acquired through out the centuries, starting from the ancient Romans. The method of silica based injection has been employed for a long time and has replaced the polyurethane injection method since the 1970s as a remedy in difficult ground conditions including fractured rock. Currently, various applications of chemical injections are available in civil and mining engineering, including ground stabilization, support anchoring, strata sealing, reduction and diversion of ground water flow and water ingress and creation of a load-bearing ring in tunneling. Drainage of the ground water in the overburden during tunneling will result in an increase in ground settlement by the evacuation of water and closure of the pores in overburden. In this research, the ground water level was decreased to 3 m from the original level and the ground settlement was recorded to reach 25 mm, while the inner tunnel vertical convergence was 6.5 mm after the drainage of 3.5 l/s ground water from the tunnel. Subsequent field measurements and observations indicated that the ground water drainage in the tunnel was reduced to 0–0.5 l/s and the surface settlements were stopped after the chemical injection.     

Doppler velocimetry of the uterine arteries after hysteroscopic rollerball endometrial ablation

The aim of this study was to document the Doppler indices [pulsatility index (PI) and resistance index (RI)] of the uterine arteries in 30 patients who underwent hysteroscopic rollerball endometrial ablation for dysfunctional uterine bleeding by transvaginal pulsed Doppler sonography, and to reveal whether treatment failures (persistent menometrorrhagia) can be predicted by the blood flow characteristics of the uterine arteries in advance. On the basis of the outcome of patients at the end of the first postoperative year, the Doppler indices of the uterine arteries were meaningful 1 year after the operation when PI (1.32 +/- 0.11; mean +/- SD) and RI (0.71 +/- 0.04) in six menometrorrhagic patients were statistically different from PI (2.19 +/- 0.28; 1.95 +/- 0.36 and 1.82 +/- 0.37) and RI (0.87 +/- 0.06; 0.82 +/- 0.06 and 0.81 +/- 0.04) in normally menstruating, amenorrhoeic and hypomenorrhoeic patients respectively (P < 0.05). On the other hand, the patients who would be menometrorrhagic one year after the operation had a thicker endometrium in the first post-operative month. These findings suggest that the angiogenetic role of the persistent endometrial islands after endometrial ablation needs at some time to be reflected as changes in the Doppler parameters of the uterine arteries.     

Soviet vacuum metallurgy

During a visit to the USSR, an intensive study by the author revealed the broad scope of Soviet research in and development of vacuum metallurgical techniques.     

The influence of gallium on the magnetocaloric properties of Gd5Si2Ge2

Gd₅Si₂Ge₂ was alloyed with varying amounts of Ga to study its influence on the giant magnetocaloric effect. Investigations on Gd₅(Si_2−xGe_2−x)Ga_2x with 2x = 0.03, 0.05 and 0.13 were carried out using X-ray powder diffraction, temperature and magnetic field dependent magnetization measurements, and differential scanning calorimetry. We observe that as the Ga content increases, the temperature stability range of the monoclinic phase narrows, and the orthorhombic structure gains stability. This is expected to be related to the decrease in the (Si/Ge)(Si/Ge) bond distance in the monoclinic phase. The maximum entropy change for the parent compound at 270 K was found to be 9.8 J kg⁻¹ K⁻¹ in an applied field of 5 T. For 2x = 0.03, this value reduces to 8.5 J kg⁻¹ K⁻¹, and the temperature corresponding to the maximum entropy change shifts marginally to 278 K. For other 2x values, the maximum entropy change further decreases.     

Production of structured lipids containing conjugated linolenic acid: optimisation by response surface methodology

Structured lipids containing conjugated linolenic acid (CLNA) were produced separately by enzymatic acidolysis reaction of corn and canola oils (CAO) with bitter gourd (Momordica charantia L) seed oil fatty acids [bitter gourd seed oil fatty acids (BGFA)]. Reactions were conducted using a commercial immobilised sn‐1,3‐specific lipase from Thermomyces lanuginosa (Lipozyme TL IM) in hexane. The effects of reaction time, substrate molar ratio, temperature and enzyme amount on incorporation yield of CLNA were investigated and optimised by response surface methodology with three‐level, two‐factor face‐centred cube design. When reactions were conducted using 10% enzyme for 3 h, the optimum reaction conditions were found for corn oil (CO) as 53.5 °C and 5.9:1 BGFA/CO molar ratio. At these conditions, the incorporation of CLNA into CO was determined as 41.4%. However, CLNA incorporation into CAO was resulted as 37% at optimum conditions which were 54.2 °C and 6.8:1 BGFA/CAO molar ratio.     

Prediction of building energy needs in early stage of design by using ANFIS

Studies performed on the prediction of building energy consumption are increasingly important for selecting the best control strategies against the excessive energy consumptions. This paper presents Adaptive Network Based Inference System (ANFIS) model to forecast building energy consumption in a cold region. The objective of this paper is to examine the feasibility and applicability of ANFIS in building energy load forecasting area. Different combinations of building samples formed by using three different form factors (FF 1/2, FF 1/1 and FF 2/1), nine azimuth angles varied 0^o–80^o, three transparency ratios of 15%, 20%, 25% and five insulation thicknesses of 0, 2.5, 5, 10 and 15 cm. Finally, it is observed that ANFIS can be a strong tool with the 96.5 and 83.8% for heating and cooling energy prediction in pre-design stage of energy efficient buildings for choosing the best combinations.     

Performance of batch solid state fermentation for hydrogen production using ground wheat residue

Ground wheat (21 g) was subjected to batch solid state dark fermentation for bio-hydrogen production. Clostridium acetobutylicum (B-527) was used as the culture of dark fermentation bacteria at mesophilic conditions. Effects of moisture content on the rate and yield of bio-hydrogen formation were investigated. The highest CHF (1222 ml), hydrogen yield (63 ml H₂ g^?1 starch), formation rate (10.64 ml H₂ g^?1 starch h^?1) and specific hydrogen formation rate (0.28 ml H₂ g^?1 biomass h^?1) were obtained with a moisture content of 80%. Nearly complete starch hydrolysis and glucose fermentation were achieved with more than 80% moisture content and the highest substrate conversion rate (21.9 mg L^?1 h^?1) was obtained with 90% moisture content at batch solid state fermentation producing volatile fatty acids (VFA) and H₂.     

Preparation of Novel Sensors Based on Polyimide Membrane for Sensitive and Selective Determination of Dopamine

Polyimides as dopamine selective membrane were prepared from 4,4′-diaminodicyclohexylmethane and different dianhydrides. The chemical structure and thermal properties of these polyimides were examined. For the voltammetric sensor applications, polyimides exhibited suitable glass transition temperature (T_g), high thermal stability, and good adhesive properties. Moreover, polyimides were coated onto Pt electrode surface for the preparation of dopamine selective electrodes. Electrochemically dopamine responses of polyimide-coated electrodes were examined by differential pulse voltammetry. The sensor characteristics such as sensitivity, linearity, selectivity, response time, and stability of the prepared sensors have been determined. Prepared polyimide-coated electrodes can be used for selective and sensitive dopamine detection.