A locally computed suboptimal control strategy for a class of interconnected systems

In this paper, a locally computed suboptimal control strategy for a class of interconnected systems is introduced. First, optimal statefeedback control equations are derived for a finite-horizon quadratic cost. Then, the control for each subsystem is separated into two portions. The first portion stabilizes the isolated subsystem, and the second portion corresponds to the interactions. To achieve a locally calculable control, an approximation to the optimal control equations is introduced, and two iterative suboptimal control algorithms are developed. In the first algorithm, the initial conditions of subsystems are assumed to be known; in the second algorithm, this information is replaced by statistical distributions. The orders of errors in the iterations of the algorithm and in the suboptimality are given in terms of interconnections. An example with comparisons is also included to show the performance of the approach.     

The Effect of Selenium Supplementation on the NMR Proton Relaxation Time T1 in Plasma

Selenium has been identified as an essential dietary trace e1ementQ)which is a component of glutathione peroxidase (GSH-Px)(₂)and a cytochrome C-like protein(₃), The enzyme,the four subunits of which each contain one atom of selenium in the form of selenocysteine, the selenium containing active centre being amenable to chemical modification, catalyses the reduction of H,O,and organic hydroperoxides to water.In this way GSH-Px plays an important role in the protection of the cell from oxidative stresses such as the superoxide anion,organic hydroperoxides and H₂O₂     

Regional Differences in Rice Hulls Supply for Bioethanol Production

Agricultural by-products are becoming an attractive substrate for bioethanol production. The aim of this study was to evaluate the effects of regional differences in the rice hulls using Escherichia coli KO11 for bioethanol production. The rice hulls coded Edirne were obtained from Thrace Region, and the rice hulls coded Izmir were obtained from Aegean Region in Turkey. Rice hulls were treated by dilute acid before using them as substrates. The cells were incubated on an orbital shaker at 160 rpm under 30 °C during 96 h of the fermentation period. It was found that the maximum yield of ethanol from sugar (0.44 g ethanol/g reducing sugar) was obtained with the substrate C/N ratio of 29.16 in Izmir medium. The main difference was the dominant carbon source available as a substrate. It was detected that glucose concentration was about 2.5 times higher in Izmir medium, whereas xylose concentration was about two times higher in Edirne medium. The different results obtained with rice hulls from different origins could depend on the type of paddy as well as different cultivation conditions. These findings provide a valuable indicator for identifying suitable agricultural waste materials to be used as substrates for bioethanol production.     

Semi-continuous Cultivation of Haematococcus pluvialis for Commercial Production

The objectives of the present study on the growth of Haematococcus pluvialis were to indicate the effects of a long-term semi-continuous cultivation, sterilization, carbon dioxide, and different culture media by using artesian well water. This investigation was an enterprise in order to commercialize the production economically. When the effect of CO₂ was investigated in basal culture medium, the influence of sterilization was also researched in Rudic’s culture medium in vertical panel-type photobioreactors for 31 days of semi-continuous cultivation. The maximum cell concentration of 10.55?×?10⁵ cells ml^?1, which corresponds to the growth rate of 0.271 day^?1 with the areal productivity of 3.531 g m^?2 day^?1, was found in non-sterilized RM medium on the 24th day of the third run of semi-continuous cultivation at a renewal rate of 50% in a vertical panel-type photobioreactor.     

Two Approaches for State Space Realization of NARMA Models: Bridging the Gap

This paper studies the necessary and sufficient conditions for observable realization of a general class of nonlinear high-order input-output difference equations. In particular, it proves the equivalence of the two seemingly different existing approaches in the literature. The paper also provides a subclass of NARMA input-output models that are guaranteed to have an observable realization. It is shown that this class covers several important subclasses of existing NARMA models.     

Temperature dependency of thermal conductivity of solid phases for fatty acids

Thermal conductivity variations with temperature of solid phases for lauric acid (LA), myristic acid (MA), pivalic acid (PA), and stearic acid (SA) have been measured with radial heat-flow method. Temperature dependencies of the thermal conductivity for same organic materials have been obtained by linear regression analysis. From graphs of thermal conductivity versus temperature, the thermal conductivity of solid phase at their melting temperature and temperature coefficients of thermal conductivity for LA, MA, PA, and SA have been found to be 0.37, 0.39, 0.23, and 0.35 W K^?1 m^?1 and 0.00935, 0.00446, 0.01095, and 0.00295 K^?1, respectively. The ratios of thermal conductivity of liquid phase to thermal conductivity of solid phase for LA, MA, PA, and SA have also been measured to be 0.52, 0.48, 0.25, and 0.59, respectively, with a Bridgman-type directional solidification apparatus.     

Determination of total attenuation cross sections of Ti, Fe, Ni, Zn between 4.551–111.898 keV energy range

The total attenuation cross sections in elements Ti, Fe, Ni and Zn for K and K group of liens of element 22Z92 by using tranmission method. K X-rays of seconder excitor were counted by a Ge(Li) detector with resolution 190 eV at 5.9 keV. The experimentally mesured attentuation cross sections have ben found in a good agreement with the theoretical values of Stom, Israel and Hubbell, Seltzer.     

13C NMR spectroscopy of naturally occurring iridoid glucosides and their acylated derivatives

The ¹³C NMR spectra of twenty one iridoid glucosides and fourteen acyl iridoid glucosides of various cyclopentane oxidation states have been analysed and their carbon shifts assigned. Evidence is presented which demonstrates that ¹³C NMR spectroscopy is a valuable and reliable technique for distinguishing the sites of acylation in iridoid glucosides and confirming the predictions of the configuration at C-6 and C-8. A cis configuration of vicinal substituents is generally associated with a substantial increase in shielding, as compared with the trans analog. The ring size and C-1 configuration in the glucose moiety are also evident from the spectra.     

Association of the XRCC1 gene polymorphisms with cancer risk in Turkish breast cancer patients

The X-ray repair cross-complementing group 1 (XRCC1) gene is believed to play an important role in base excision repair and displays genetic polymorphisms. Data on the role of XRCC1 polymorphisms in cancer susceptibility is inconsistent. In the present study, we investigated the effect of two XRCC1 polymorphisms, Arg194Trp and Arg399Gln, on breast cancer risk in a case- control study involving Turkish breast cancer patients and healthy women. Both alleles exhibited a similar distribution among cases and controls leading to lack of any significant association between the XRCC1 polymorphisms and breast cancer risk, either in homozygotes and heterozygotes or combined. The allele frequency of the codon 194 variant was very low in cases and healthy individuals (5.3 and 3.9%, respectively) compared to that of the variant 399Gln allele (39.7 and 37.4%). Our results do not support evidence for a role of the XRCC1 polymorphism in developing breast cancer.