A power-adaptable A/D converter with integrated data compression

A novel adaptable analog/digital converter (ADC) that combines analog/digital conversion and entropy-coding for integrated data compression and low-power operation is reported. The converter has high flexibility of operation in terms of adaptable resolution, conversion rate and input signal statistics. This feature allows to adaptively react to changes of the situation and to put the device in each case into the optimum configuration. The ADC has been realized in a 0.6 μm CMOS technology with a peak resolution of 12 bit and 200 kS/s maximum sampling rate. A comprehensive power model of the converter is presented that reflects precisely the power consumption determined from experiments. The model is very useful for optimizing the converter configuration in the node of a wireless sensor network for specific situations. A feasible real-life application is demonstrated.     

Sulfidogenic fluidized-bed treatment of metal-containing wastewater at 8 and 65 degrees C temperatures is limited by acetate oxidation

Acetate utilization in sulfidogenic fluidized-bed reactors (FBRs) was investigated for the treatment of iron containing wastewater at low (8 degrees C) and high (65 degrees C) temperatures. The FBRs operated at low and high temperatures were inoculated with cultures of sulfate-reducing bacteria (SRB) originally enriched from arctic and hot mining environments, respectively. Acetate was not utilized as a carbon and electron source for SRB at 8 degrees C. With ethanol, hydrogen sulfide was produced from ethanol to acetate oxidation, which precipitated the iron. Then, several attempts were made to obtain acetate oxidation at 8 degrees C. Inoculation of two different low temperature enrichments and operating the FBR for a long period of time (321 days) did not result in enrichment of acetate oxidizing SRB. Due to the absence of acetate oxidation at 8 degrees C, external alkalinity addition was required to keep the pH neutral. At 65 degrees C, average acetate and sulfate removals were 52+/-12% and 24+/-8% at 670 mg/Ld acetate and 1500 mg/Ld sulfate loadings, respectively. The produced alkalinity from acetate oxidation increased the pH from 6.4 to around 7.5 and electron flow to sulfate reduction averaged 65%. Denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA genes showed quite stable SRB community at 8 degrees C, whereas, at 65 degrees C SRB community was dynamic. In the FBRs, Desulfomicrobium apsheronum and Desulfosporosinus sp. at 8 degrees C and Desulfotomaculum sp. at 65 degrees C were detected.     

The microencapsulation of terbinafine via in situ polymerization of melamine‐formaldehyde and their application to cotton fabric

In this study an antifungal pharmaceutical agent, terbinafine, was microencapsulated by using in situ polymerization. The polymerization was carried out at four mole ratio level and preparations were applied to the 100% cotton fabric. X‐ray diffractometry, DSC, FTIR, BET, contact angle measurements, particle size distribution and imaging techniques were performed. Best results were obtained in the case of 8 : 1 mole ratio. Strength of microcapsule applied fabrics to washing and fungus were also determined. After 25 washing cycle, microcapsules were still in the fabric and had antifungal properties against A. niger. Antifungal strength against T. rubrum was observed up to 15 washing cycles. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Numerical Analysis of a Tunnel Support Design in Conjunction with Empirical Methods

In this paper, preliminary support design of a tunnel was analyzed by numerical and empirical approaches. The case study for this analysis is a tunnel to be constructed on the Bilecik-Istanbul roadway in Turkey. The rock mass properties of the tunnel route and design support recommendations were obtained by using an empirical approach. The rock mass properties obtained from the empirical method were used as input parameters for the numerical analysis. The empirical and numerical results, in terms of support design, were evaluated. It was seen that the numerical analysis results supported by empirical values were logical and reliable.     

Electricity demand analysis using cointegration and ARIMA modelling: A case study of Turkey

In the early 2000s, the Republic of Turkey has initiated an ambitious reform program in her electricity market, which requires privatization, liberalization as well as a radical restructuring. The most controversial reason behind, or justification for, recent reforms has been the rapid electricity demand growth; that is to say, the whole reform process has been a part of the endeavors to avoid the so-called “energy crisis”. Using cointegration analysis and autoregressive integrated moving average (ARIMA) modelling, the present article focuses on this issue by both providing an electricity demand estimation and forecast, and comparing the results with official projections. The study concludes, first, that consumers’ respond to price and income changes is quite limited and therefore there is a need for economic regulation in Turkish electricity market; and second, that the current official electricity demand projections highly overestimate the electricity demand, which may endanger the development of both a coherent energy policy in general and a healthy electricity market in particular.     

CCII-based PID controllers employing grounded passive components

In this paper, both of current-mode and voltage-mode proportional plus integral plus derivative (PID) controllers employing the second-generation current conveyors (CCIIs) as active elements are developed. The presented novel PID controllers have grounded passive elements that do not need passive element matching, and realize independently adjustable PID parameters. Thus, it is easy to implement these PID controllers in integrated circuits. Several computer simulations are presented to demonstrate the behavior of these proposed PID controllers.     

An exposé of bioenergy and its potential and utilization in Turkey

Turkey is heavily dependent on expensive imported energy resources (oil, gas and coal) that place a big burden on the economy. Air pollution is also becoming a great environmental concern in the country. In this regard, renewable energy resources appear to be one of the most efficient and effective solutions for clean and sustainable energy development in Turkey. Turkey's renewable sources are the second largest source for energy production after coal. About two-thirds of the renewable energy produced is obtained from bioenergy, which is used to meet a variety of energy needs, including generating electricity, heating homes, fueling vehicles and providing process heat for industrial facilities. The amount of usable bioenergy potential of Turkey is approximately 17 Mtoe. This article not only presents a review of the potential and utilization of the bioenergy in Turkey but also provides some guidelines for policy makers.     

Material Flow Control in High Pressure Sheet Metal Forming of Large Area Parts with Complex Geometry Details

Working media based forming processes show advantages compared to the conventional deep drawing in the range of sheet metal parts with complex geometry details. By High Pressure Sheet Metal Forming (HBU), complex parts can be formed with reduced tool costs, fewer process steps, and improved part properties, particularly by the use of high strength steels. In order to use these advantages to full capacity, the material flow into the area of the geometry details needs to be optimised. The key element for the material flow control is a multi‐point blank holder. In combination with flange draw‐in sensors, a closed loop flange draw‐in control can be built up which guarantees a reproducible material flow and, consequently, defined part properties. Furthermore, a favourable pre‐distribution of sheet metal material can be reached which leads to a widening of the process limits. Considering a large area sheet metal part with a complex door handle element as example, strategies for the material flow control will be discussed in this paper. The conclusions are based on FE‐simulations as well as experimental findings.     

Stability problems in universal current-mode filters

Analog circuit designers have usually focused on the design of circuits employing a minimum number of components, occupying less area and dissipating less power. However, some important issues such as signal limitations and especially stability problems of the analog circuits have not received considerable attention in the literature. Hence, the work described in this paper deals with the stability problems of two new current-mode analog filters employing multiple output current controlled conveyors (MOCCCIIs). Toward that end, a single pole model is replaced for each non-ideal current gain of the MOCCCIIs. Both of the novel universal current-mode active-C filters can simultaneously realize low-pass, band-pass and high-pass/notch filter responses. SPICE and MATLAB simulation results are given to verify the theoretical analysis.