3GPP LTE‐Assisted Wi‐Fi‐Direct: Trial Implementation of Live D2D Technology

This paper is a first‐hand summary on our comprehensive live trial of cellular‐assisted device‐to‐device (D2D) communications currently being ratified by the standards community for next‐generation mobile broadband networks. In our test implementation, we employ a full‐featured 3GPP LTE network deployment and augment it with all necessary support to provide real‐time D2D connectivity over emerging Wi‐Fi‐Direct (WFD) technology. As a result, our LTE‐assisted WFD D2D system enjoys the required flexibility while meeting the existing standards in every feasible detail. Further, this paper provides an account on the extensive measurement campaign conducted with our implementation. The resulting real‐world measurements from this campaign quantify the numerical effects of D2D functionality on the resultant system performance. Consequently, they shed light on the general applicability of LTE‐assisted WFD solutions and associated operational ranges.     

Bestimmung des Grenzumformgrades mit dem Torsionsversuch

Die Bestimmung des Grenzumformgrades eines Stahles, der während der plastischen Verformung nicht überschritten werden kann, ist von großer Bedeutung. Die vorliegende Arbeit berichtet über Ergebnisse von Warmtorsionsversuchen, aus denen der Grenzumformgrad als Funktion von Temperatur und Umformgeschwindigkeit ermittelt wurde. Die Versuche wurden an den Stählen X 10 CrNiTi 18 9, 10 CrMo 9 10, X 10 CrNiMoTi 18 12, X 20 CrMoV 12 1 und X 2 NiCrNb 25 18 durchgeführt.     

Case Study: Refinement of Hydraulic Operation of a Complex CSO Storage/Treatment Facility by Numerical and Physical Modeling

The performance of a combined sewer overflow (CSO) storage/treatment facility in North Toronto, Ont., Canada, was investigated by conjunctive numerical and physical (hydraulic) modeling. The main objectives of the study were to (1) assess the feasibility of increasing the hydraulic loading of the CSO facility without bypassing; and (2) establish a verified numerical model of the facility for future work. The numerical model [a commercial computational fluid dynamics (CFD), PHOENICS] was validated and verified using results from a hydraulic scale model (1:11.6). The results obtained show that the CFD model can simulate hydraulic conditions in the facility well, as demonstrated by accurate reproduction of the filling rate, water levels at various locations, flow velocities in feed pipes, and overflows from the inflow channel. Numerical simulations identified excessive local head losses and helped select structural changes to reduce such losses. The analysis of the facility showed that with respect to hydraulic operation, the facility is a complex, highly nonlinear hydraulic system. Within the existing constraints, a few structural changes examined by numerical simulation could increase the maximum treatment flow rate in the CSO storage/treatment facility by up to 31%.     

Oil:Oil Correlation for Some Oil Fields in the North Western Part of the Western Desert, Egypt

Physical and specific geochemical analyses are used in detail for the petroleum geochemical studies to permit the correlation of six crude oil samples from Western Desert Egypt. Different analytical techniques, including liquid chromatographic separation, gas chromatography, and gas chromatography-mass spectrometry (GC-MS), were used to characterize the oil samples. The oils were identified using oil characterization parameters including specific gravity (°API), sulfur content, distribution of n-alkanes, carbon preference index (CPI), pristane/phytane ratio, isoprenoid/n-alkane ratios, and detailed biological marker analysis. All these parameters showed that the studied oil samples are correlated with each other, where they are similar in their oil type maturation and source depositional environments.     

Throughput bounds for closed queueing networks

Analytical lower and upper bounds for the throughput of closed queueing networks with single and delay (infinite) servers are studied in this paper. The numerical evaluation of these bounds requires a small number of significant operations which is independent of the population N. This is in contrast to the exact computation of the throughput which requires at least O(N) operations as N tends to infinity. The bounds are given by simple closed-form analytical expressions and may be more suitable for various performance studies than the algorithmical form of the exact solution.In this paper, the previously known balanced-job bounds are generalized to networks containing delay servers (terminals) and a hierarchy of bounds is obtained for single and multiple class networks. For the single class network, further new bounds are derived: lower and upper bounds that require the evaluation of one square root and an upper bound that requires a constant number of exponentiations. This upper bound does not employ the balancing of server loadings and is especially useful for asymptotic analysis in the case of a large number of customers N.     

Transmission parameters of a class of coupled distributed networks

It is shown how the equations of a class of coupled distributed networks can be decoupled, and their transmission parameters expressed in terms of those of an equivalent scalar system.     

Dietary sitostanol and campestanol: Accumulation in the blood of humans with sitosterolemia and xanthomatosis and in rat tissues

Dietary sitostanol has a hypocholesterolemic effect because it decreases the absorption of cholesterol. However, its effects on the sitostanol concentrations in the blood and tissues are relatively unknown, especially in patients with sitosterolemia and xanthomatosis. These patients hyperabsorb all sterols and fail to excrete ingested sitosterol and other plant sterols as normal people do. The goal of the present study was to examine the absorbability of dietary sitostanol in humans and animals and its potential long-term effect. Two patients with sitosterolemia were fed the margarine Benecol (McNeill Nutritionals, Ft. Washington, PA), which is enriched in sitostanol and campestanol, for 7–18 wk. Their plasma cholesterol levels decreased from 180 to 167 mg/dL and 153 to 113 mg/dL, respectively. Campesterol and sitosterol also decreased. However, their plasma sitostanol levels increased from 1.6 to 10.1 mg/dL and from 2.8 to 7.9 mg/dL, respectively. Plasma campestanol also increased. After Benecol withdrawal, the decline in plasma of both sitostanol and campestanol was very sluggish. In an animal study, two groups of rats were fed high-cholesterol diets with and without sitostanol for 4 wk. As expected, plasma and liver cholesterol levels decreased 18 and 53%, respectively. The sitostanol in plasma increased fourfold, and sitostanol increased threefold in skeletal muscle and twofold in heart muscle. Campestanol also increased significantly in both plasma and tissues. Our data indicate that dietary sitostanol and campestanol are absorbed by patients with sitosterolemia and xanthomatosis and also by rats. The absorbed plant stanols were deposited in rat tissues. Once absorbed by sitosterolemic patients, the prolonged retention of sitostanol and campestanol in plasma might increase their atherogenic potential.     

Oxidized cellulose: An application in the form of sorption filter materials

Oxidized cellulose (oxycellulose) was very effectively used in the form of filter sheets to remove some metal ions from water and from aqueous solutions. Furthermore, oxycellulose was applied in an ion‐exchange column and in a batch process. The mechanisms of the sorption process inside oxycellulose as well as the kinetics of sorption were studied. A comparison of oxycellulose and other adsorption components such as zeolites and ion‐exchange resins was made. The affinity of oxycellulose to metal ions was determined to be in the following order: Cd²⁺, Zn²⁺ > Ni²⁺ ? Ca²⁺ > Mg²⁺ ? Na⁺. The use of oxycellulose was very effective, especially in the form of sorption filters, because this allowed us to use a simple filtration process. Moreover, the specific loading amount of the filter cake was higher for filtration than for the column process under comparable conditions. Oxycellulose in a glass column behaved similarly to an ion‐exchange resin. It showed approximately constant efficiency until the sorption capacity of the adsorbent was exhausted, and then it suddenly dropped. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The use of silver solid amalgam electrode for voltammetric and amperometric determination of nitroquinolines

Solid amalgam electrodes represent a suitable alternative to mercury electrodes due to their similar electrochemical properties and non-toxicity of the amalgam material. Nitro derivatives of quinoline have been proven to be genotoxic, thus their presence in environmental samples is a legitimate cause for concern.In this contribution, meniscus modified silver solid amalgam electrode (m-AgSAE) was employed for the batch voltammetric determination and amperometric determination in connection with flow injection analysis of 5-nitroquinoline and 6-nitroquinoline (5-NQ, 6-NQ). Their electrochemical behavior was characterized by cyclic voltammetry, for their determination direct current voltammetry and differential pulse voltammetry were used. Linear calibration curves in the concentration range of 2 × 10⁻⁷ to 1 × 10⁻⁴ mol L⁻¹ were obtained. These results are comparable with results obtained for polarographic determination of the same substances using mercury electrodes. Further, the meniscus modified silver solid amalgam electrode was employed in amperometric detection cell in “wall jet” arrangement for determination of 5-NQ in flow injection analysis. Under optimized conditions (run buffer 0.05 mol L⁻¹ borate buffer, pH 9.0; flow rate 4 mL min⁻¹; detection potential −1.6 V; injection volume 0.1 mL), the limit of quantitation of ∼4 × 10⁻⁶ mol L⁻¹ was achieved. The repeatability of the detector response is satisfactory (relative standard deviation ∼2.15% for c(5-NQ) = 1 × 10⁻⁴ mol L⁻¹). Practical applicability of the method was verified for the determination of micromolar concentrations of 5-NQ in drinking and river water model samples.