Frequency dependence of the complex dielectric constant of sodium carboxymethyl cellulose

The dielectric constant, ε′, and dielectric loss, ε″, were determined for three solid carboxymethyl cellulose samples having different levels of substitution and different degrees of polymerization over a frequency range of 0.1 – 10 000 kHz at temperatures from 10–60°C. In contrast to the two relaxation processes, γ and β, previously observed in native cotton cellulose, only one relaxation process within a frequency range of 0.1 – 1 kHz was identified. It was found that the dielectric properties do not only depend on the degree of substitution, but also on the weight-average degree of polymerization and uniformity of distribution.     

Iterative interference cancellation for high spectral efficiencysatellite communications

The problem of efficient utilization of the frequency spectrum for satellite systems is investigated; one which results as a consequence of highly crowding adjacent channels. An analytical characterization of the resulting interference channel is introduced and then exploited for interference cancellation. Two classes of cancelers are investigated. The first approach does not benefit from the forward error control (FEC) coding information which limits the performance gain. This motivates the second approach where a joint implementation of interference cancellation and decoding is developed using soft-input-soft-output (SISO) modules along with the iterative structure. It is shown that iterative interference cancellation techniques can achieve significant gains compared with the single-user matched filter receiver     

Capillarovenous angioma of the maxillary sinus. Apropos of a case with review of the literature

Metabolic side-effects of antihypertensive drugs may increase the risk of coronary heart disease despite an adequate blood pressure reduction. Since combinations of different antihypertensive drugs are often necessary and frequently used, we performed a randomized study comparing the effects of a fixed combination of hydrochlorothiazide and sotalol (group A), or hydrochlorothiazide and captopril (group B) on blood pressure and on lipid and glucose metabolism in 40 men with essential hypertension over 1 year. Significant blood pressure reductions (p < 0.001) were achieved in both treatment groups: from 160/105 to 128/88 mmHg in group A (mean doses: hydrochlorothiazide 33 and sotalol 197 mg) and from 162/106 to 135/89 mmHg in group B (hydrochlorothiazide 33 and captopril 64 mg) after 12 months, respectively. No significant changes in body weight were observed in either treatment group. Triglycerides increased (p < 0.05) in both treatment groups (from 183 to 262 mg/dl in A, and from 160 to 196 mg/dl in B) and HDL cholesterol decreased (p < 0.001 and < 0.05) in both groups (from 45.1 to 35.7 mg/dl in A, and from 49.3 to 46.3 mg/dl in B), whereas LDL cholesterol increased significantly (p < 0.05) only in group A from 153 to 164 mg/dl. No significant changes were observed in total cholesterol nor in lipoprotein(a) concentrations in either treatment group. Fasting plasma glucose and hemoglobin A1 increased significantly (p < 0.05) only in group A after 1 year of treatment (from 91.6 to 98.0 mg/dl, and from 6.3 to 6.9%, respectively). Serum levels of creatinine and potassium decreased, and uric acid increased significantly under either combination. Our data show that the diuretic/beta-blocker combination has adverse effects on lipid and glucose metabolism after long-term therapy. The effects of the diuretic/ACE inhibitor combination on lipid metabolism are less pronounced and there are no adverse effects on glucose metabolism. However, the ACE inhibitor component could not completely counteract the metabolic effects of the diuretic. Both combinations have no effects on Lp(a). We conclude that the combination of hydrochlorothiazide with an ACE inhibitor has a better metabolic profile for the treatment of essential hypertension than the combination with a beta-blocker.     

An efficient algorithm for maxdominance, with applications

Given a planar setS ofn points,maxdominance problems consist of computing, for everyp S, some function of the maxima of the subset ofS that is dominated byp. A number of geometric and graph-theoretic problems can be formulated as maxdominance problems, including the problem of computing a minimum independent dominating set in a permutation graph, the related problem of finding the shortest maximal increasing subsequence, the problem of enumerating restricted empty rectangles, and the related problem of computing the largest empty rectangle. We give an algorithm for optimally solving a class of maxdominance problems. A straightforward application of our algorithm yields improved time bounds for the above-mentioned problems. The techniques used in the algorithm are of independent interest, and include a linear-time tree computation that is likely to arise in other contexts.The research of this author was supported by the Office of Naval Research under Grants N00014-84-K-0502 and N00014-86-K-0689, and the National Science Foundation under Grant DCR-8451393, with matching funds from AT&T.This author's research was supported by the National Science Foundation under Grant DCR-8506361.     

Effect of SiO2 Addition on Chromium Transitions in Borate Glasses

Silicon - Melt-quenching technique was used to prepare borosilicate glasses of composition xSiO2- (75-x) B2O3–24.7Li2O-0.3Cr2O3 (x = 0, 10, 20, 30, 40 and 50&nbsp;mol%). With...     

Physicochemical investigation of the decomposition products of ammonium metal carboxylates: ammonium ferric citrate hydrate

The thermal decomposition up to 400 °C of ammonium ferric citrate hydrate, of unknown structure and formula weight, was studied by thermogravimetry, differential thermal analysis, infrared (IR) spectroscopy and X-ray diffractometry. The possible identities of the formula weight and the intermediate products of calcination are discussed. The results revealed that the parent material is amorphous and contains two moles of water and two moles of ammonia. Decomposition takes place via six weight-loss processes, three endothermic (90–230 °C) and three exothermic (240–298 °C), leading eventually to the formation of Fe₂O₃. The intermediate solid products are mainly unstable amorphous oxycarbonates, as indicated by X-ray and IR spectroscopies. The gas-phase decomposition products identified by IR spectroscopy are NH₃, CO₂, CO, CH₃COCH₃, CH₄ and NH₄OH. Surface area measurement and scanning electron microscopy showed that Fe₂O₃, the final product at 400 °C, hada surface area of 40 m²/g and good crystalline and porous character.     

Modification of sandy soil using water‐borne polymer

A new polymeric system has been applied for structural modification of (noncompactable) sandy soils. The system is based on a water‐borne styrene acrylic polymeric formulation (emulsion) containing varying amounts of solid polymer. The present work deals with system optimization and measurements designed to examine the effects of polymer content on hydraulic conductivity and compressive strength. Samples were prepared from prescribed amounts of polymer, water, and sand by using two different preparations methods (mixing and spraying). Measurements of hydraulic conductivity for both sets of samples were conducted in a flexible membrane test apparatus. For the first set of samples, the permeability coefficient of the sand was noted to be reduced 10‐fold (from 10^?5 to 10^?6 m s^?1) upon the incorporation of about 2% polymer. In the second set (samples prepared with the spraying method), the hydraulic conductivity was further reduced to 7.2 × 10^?7 at a polymer concentration of about 2%. Stress–strain measurements made on dry cylindrical specimens disclosed remarkable enhancement in the mechanical behavior of the system. For both types of preparation methods, the compressive strength and modulus of elasticity increased linearly with the polymer concentration in the sample. Scanning electron microscopic examination revealed that the dramatic reduction in the permeability and the improved mechanical properties are attributed to the polymer coverage of the sand particles and the development of interconnecting ties between them. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2484–2491, 2003     

An efficient IoT based smart farming system using machine learning algorithms

Multimedia Tools and Applications - This paper suggests an IoT based smart farming system along with an efficient prediction method called WPART based on machine learning techniques to predict crop...     

Image Super Resolution and Enhancement Using E-spline

E-splines （Exponential spline） polynomials represent the best smooth transition between continuous and discrete domains. As they are constructed from convolution of exponential segments, there are many degrees of freedom to optimally choose the most convenient E-spline, suitable for a specific application. In this paper, the parameters of these E-splines were optimally chosen, to enhance the performance of image zooming and interpolation schemes. The proposed technique is based on minimizing the total variation function of the detail coefficients of the E-spline based wavelet decomposition. In zooming applications, the quality of interpolated images are further improved and sharpened by applying ICA technique to them, in order to remove any dependency. Illustrative examples are given to verify image enhancement of the proposed E-spline scheme, when compared with the existing approaches.