A new decentralized controller for large scale systems

In this paper we develop a new approach to the design of near-optimal decentralized controllers for large-scale linear interconnected dynamical systems. All calculations in the design stage are done on subsystems. This is achieved by using a simple reduced order model for the interactions. The resulting controller is decentralized, independent of initial conditions and capable of accommodating constant unknown disturbances. The approach is illustrated on a 22nd order river pollution control example. In addition, it is shown that by a simple modification it is possible to ensure that the controller is asymptotically stable with a pre-specified degree of stability and we show that the modified controller is also connectively asymptotically stable under structural perturbations.     

Remote-sensing and GIS-based landslide-susceptibility zonation using the landslide index method in Igo River Basin,Eastern Himalaya,India

A remote-sensing and geographical information sysytem (GIS)-based quantitative methodology for landslide-susceptibility zonation is described in a stepwise manner with its application in the Igo River Basin in the West Siang District of Arunachal Pradesh, Eastern Himalaya, India. Parameters such as geology, physiography, slope angle, slope length, slope aspect, slope type, generic landforms, lineament distance, road distance, drainage distance, altitudinal zones and land cover are used for landslide-susceptibility zonation. The quantitative relation between landslides and the selected parameters is established through the landslide index method of the International Institute for Geo-Information Science and Earth Observation (ITC), The Netherlands, by assigning weights. A weight value for a certain parameter class is defined as the natural logarithm of the landslide density in the class divided by the landslide density in the entire map. The final layer containing the composite index is divided into seven landslide-susceptibility categories. The maximum portion of the study area experiences moderately low to moderate landslide susceptibility, and each portion occupies an area of 91 km², representing 30% of the total area. High concentrations of very high and extremely high-susceptibility landslide areas are noticed in the steep slope areas, especially in the Sub-Himalayas. The settlements are found in the safe areas of very low, low and moderately low landslide-susceptibility categories. About 9% and 1.99% of the roads are exposed to high and very high landslide-susceptibility areas, respectively. About 15% of the slash-and-burn cultivation (jhum) is found along the high-susceptibility areas, 3.89% is found in very high-susceptibility areas and 0.19% is prone to extremely high susceptibility. The high-susceptibility zones are also found under dense and moderately dense forests.     

PROCESSING AND STORAGE OF CARBONATED GUAVA BEVERAGE

Guava cv.'Allahabad Safeda'was crushed and treated with pectic enzymes at 0.1% concentration (w/v), incubated for 1 h at 40–50C and the liquefied juice having 10.8 Brix and 0. 65% acidity was used for carbonation. The juice was converted into sugar syrup base having 40% guava juice at 40 Brix and 1% acidity. After dosing 50 ml of it into a glass bottle (200ml capacity) filled with chilled (4-6C) carbonated water at 80 psi pressure of CO₂ gas, the bottle was sealed with crown cork and heat processed at 60C for 30 min. The carbonated guava beverage could be stored for 3 months at room (23-41C) and low (3-5C) temperatures and was found acceptable with respect to color, flavor and overall quality. Heat processing improved the flavor of the carbonated guava beverage, and the beverage contained no detectible microbes.     

An investigation of the L-shell x-ray conversion efficiency for laser-irradiated tin foils

We have used the Shenguang Ⅱ laser in third harmonic(351 nm) to investigate the emission of L-shell radiation in the 3.3–4.4 ke V range generated using thin foils of Sn coated onto a parylene substrate with irradiation of order 10~(15) W cm~(-2) and nanosecond pulse duration. In our experiment, we have concentrated on assessing the emission on the non-laser irradiated side as this allows an experimental geometry relevant to experiments on photo-ionised plasmas where a secondary target must be placed close to the source, to achieve x-ray fluxes appropriate to astrophysical objects. Overall L-shell conversion efficiencies are estimated to be of order 1%,with little dependence on Sn thickness between 400 and 800 nm.     

Zinc electrowinning from acidic sulfate solutions: Part I: Effects of sodium lauryl sulfate

The effects of sodium lauryl sulphate(SLS) in the presence and absence of antimony(iii) on the current efficiency, power consumption and polarization behaviour of zinc were determined. The surface morphologies and deposit crystallographic orientations were also evaluated. The results were compared with glue as the addition agent. The addition of sodium lauryl sulfate to the zinc sulfate solution increased current efficiency, reduced power consumption and improved the surface morphology. Maximum current efficiency and minimum power consumption were achieved on addition of 0.02mgdm–3 Sb with 1mgdm–3 sodium lauryl sulfate.     

Factors Affecting Amine Production by a Selected Strain of Lactobacillus bulgaricus

Lactobacillus bulgaricus-52 showed maximum growth and amine production in MRS broth in 24 hr at 37°C. The optimum pH for the production of histamine, tyramine, and tryptamine by L. bulgaricus-52 was 5.0. Highest yields of the different amines were obtained in the absence of NaCI in the growth medium. A concentration of even 0.5% NaCI had a slight inhibitory affect on the synthesis of amines. A similar trend was observed in terms of amine production by L bulgaricus-52 in milk samples held at 37°C for different time intervals.     

Estimation of thermal expansion behaviour of some refractory carbides and nitrides

Lattice parameters of some refractory carbides and nitrides were estimated up to 2400 K using an empirical approach. The computed lattice parameters are in very close agreement (±0.5%) with the values calculated from experimental thermal expansion data reported in the literature. This empirical approach with modifications may be applicable to the prediction of the thermal expansion behaviour of other classes of high temperature materials. This revised version was published online in November 2006 with corrections to the Cover Date.     

RHEOLOGICAL PROPERTIES OF CHEMICALLY MODIFIED RICE STARCH MODEL SOLUTIONS

Native rice starches have poor resistance to shear, and fair stability to retrogradation with soft texture, which can be altered through chemical modifications. Starch from broken pieces of rice of three rice cultivars (PUSA‐44, PR‐106 and PR‐114) was chemically modified by etherification and esterification reactions by different combinations of modification reagents to investigate the effect of modification on the rheological properties of rice starches. The modification resulted in shear stable gel with apparent pseudoplastic characteristics. The viscosity of starches increased upon acetylation and dual modification as a result of increase in solubility. However, cross‐linking had shown the reverse effect. The flow behavior index (n) and consistency coefficient (k) were significantly (P ≤ 0.05) improved upon modification in acetylated and dual‐modified starches. The effect of modification on the rheological properties was observed in similar pattern in all the three rice cultivars but varied significantly in variety PUSA‐44 may be because of its relatively higher amylose content.