SLA-aware operational efficiency in AI-enabled service chains: challenges ahead

Information Systems and e-Business Management - Service providers compose services in service chains that require deep integration of core operational information systems across organizations....     

Improving outdoor air quality based on building morphology: Numerical investigation

Due to rapid urbanization around the world, high concentrations of vehicular pollutants have deteriorated the outdoor air quality, which can affect the physical and psychological well-being of humans. Numerous strategies have been proposed to overcome these harmful impacts by improving the dispersion of air pollutants. Consequently, a question arises regarding the potential effects of building morphology on the dispersion of pollutants. Subsequently, transient three-dimensional Computational Fluid Dynamics (CFD) simulations are performed to examine the effect of building morphology on PM₁₀ dispersion. Eleven cases with various prototypes and morphological methods are compared with a simple building form to identify the patterns of PM₁₀ dispersion within a given time sequence under a prevailing inflow condition. The results indicate that the different designs of building morphology with varying Relative compactness (R_C) indicator highlight the importance of considering morphological factors to improve outdoor air quality. In addition, the proposed prototypes can reduce PM₁₀ concentrations by approximately 30%–90% at specific points in the studied time sequence. In particular, the vertical, horizontal, and grid folded prototypes can be considered more effective as an approximate decrease between 70% and 90% in PM₁₀ concentrations is observed, which reflects the influence of building morphology on improving outdoor air quality.     

Geometric Charts with Estimated Control Limits

The geometric control chart has been shown to be more effective than p and np‐charts for monitoring the proportion of nonconforming items, especially for high‐quality Bernoulli processes. When implementing a geometric control chart, the in‐control proportion nonconforming is typically unknown and must be estimated. In this article, we used the standard deviation of the average run length (SDARL) and the standard deviation of the average number of inspected items to signal, SDARL*, to show that much larger phase I sample sizes are needed in practice than implied by previous research. The SDARL (or SDARL*) was used because practitioners would estimate the control limits based on different phase I samples. Thus, there would be practitioner‐to‐practitioner variability in the in‐control ARL (or ARL*). In addition, we recommend a Bayes estimator for the in‐control proportion nonconforming to take advantage of practitioners' knowledge and to avoid estimation problems when no nonconforming items are observed in the phase I sample. If the in‐control proportion nonconforming is low, then the required phase I sample size may be prohibitively large. In this case, we recommend an approach to identify a more informative continuous variable to monitor. Copyright © 2012 John Wiley & Sons, Ltd.     

PREDICTION OF BENDING FATIGUE BEHAVIOUR BY THE REFERENCE STRESS APPROACH

Abstract— A technique is presented for prediction of low-cycle fatigue behaviour under bending conditions from the knowledge of uniaxial fatigue data. The technique utilizes the reference stress approach used in the analysis of creeping components. The results enable determination of nominal elastic bending stress in terms of the observed saturation stress amplitude in an uniaxial fatigue test conducted at a reference value of strain amplitude. The reference parameters are determined for beams with both rectangular and circular cross-sections. The predictions of fatigue bending behaviour are in excellent agreement with closed form solutions reported recently. The merits of this alternative approach lie in its potential applicability to other structural situations once their reference uniaxial parameters are determined. Since the reference parameters are nearly the same for both creep and fatigue, the approach can be a useful experimental tool for relating creep-fatigue interaction effects in structural components with uniaxial creep-fatigue tests conducted under the reference conditions.     

Stability and calibration of platinum/palladium thermocouples following heat treatment

In this paper we describe the changes in the thermo EMF of Pt/Pd thermocouples in the temperature range from 0 to 1100 °C following a series of heat treatment at 960 °C. The magnitudes of the changes in EMF, the short and long term stability of the thermocouple were estimated, experimental results are presented. For the calibration of the thermocouple we have employed a reference polynomial function given in the literature [Metrologia 35 (1998) 761] for Pt/Pd thermocouples based on the International Temperature Scale of 1990 (ITS-90).     

Optical properties of evaporated Ge20Se80−x Tl x thin films

Chalcogenide glasses with composition Ge₂₀Se_80–x Tl _x (x=10, 15, 20, 25, 35%) have been prepared by the usual melt-quenching technique. Thin films of the mentioned compositions have been prepared by the electron beam evaporation. In addition, another set taken from the composition ofX=30 at % with different thicknesses (d=14.7, 30.0, 56.5, 70.0, 101.0, 180.0 nm) have been taken into consideration. The X-ray diffraction (XRD) analysis revealed the amorphous nature of the prepared films. It was found that, in contrast to the optical gap (E _op), both the extent of the band tailing (B), and the band gap (E _e) increase with increasing thallium content. In other side,E _op showed thickness independency. The refractive index (n) showed obvious dependence on both composition and thickness also on the energy of the incident radiation.     

Variations in ascorbic acid content of gramineae during germination and the effect of β- and γ- radiation

The ascorbic acid content of three types of Gramineae, viz., Triticum vulgare, Hordeum vulgare and Zea mays (Nab El-Gamal and Beladi), is given and also the average variations in the seeds during germination are shown. The effects on the seedlings of β-irradiation emitted from small doses of radioactive H₃³²PO₄ as well as by irradiation with 131 I, are investigated.     

A solar-powered LiBr dual cycle

The absorption system is one of the most suitable techniques for utilising solar energy for air-conditioning purposes. Although it uses solar energy directly with minimum conversion, it consumes considerable quantities of water for the cooling tower. This is a serious disadvantage where solar energy is available whilst water is scarce.The main purpose of this paper is to introduce the lithium bromide (LiBr) absorption cycle which avoids the use of a wet cooling tower. The characteristics of this dual cycle will be examined and new selection criteria for such solar-powered dual absorption systems will be introduced.