IR spectroscopic study on the thermal degradation of plastic security cover sheets of some documents

The change in IR spectra of plastic security cover sheets of ethylene vinylacetate copolymer during thermal treatment was investigated. The results obtained revealed that the temperature reduced the concentration of the ester group; moreover, the carbonyl band disappeared at high temperatures from 200 to 220°C, as well as broading of the absorption aliphatic–CH band. The change in the mechanical properties, degree of swelling in water, and refractive index of the samples during thermal treatment were also investigated. © 1993 John Wiley & Sons, Inc.     

The Dynamic Lot-Sizing Problem for Multiple Items Under Limited Capacity

This paper addresses the problem of scheduling the timing and quantities of production of n different products over m periods for a single production facility with a prespecified capacity. We assume that the demand is deterministic and can vary from one period to another and from one product to another. The objective is to minimize the sum of production setup and inventory holding costs. For medium-size problems, optimal solution algorithms do not yet exist and therefore heuristic solution algorithms are of interest. Most of the existing heuristics make use of the “forward-pass” concept in one way or the other. Forward pass means we begin by determining the lot sizes for earlier periods before moving to study the later periods. In this paper we study the forward-pass approach as well as a different solution approach which we call the four-step algorithm. We develop the feasibility conditions for pure forward-pass algorithms. Finally, we perform a comparative evaluation study.     

Using Semantics for Policy-Based Web Service Composition

Proliferation of Web technologies and the ubiquitous Internet has resulted in a tremendous increase in the need to deliver one-stop Web services, which are often composed of multiple component services that cross organizational boundaries. It is essential that these Web services, referred to in this paper as service flows, be carefully composed in a dynamic and customized manner to suit to the changing needs of the customers. This composition should be conducted in such a manner that (i) the composed service flow adheres to the policies imposed by the organizations offering the component services, (ii) the selected component services are compatible with one another so that the entire composition would result in a successful service flow, and (iii) the selected component services most closely meet the customer requirements. In this paper, we propose a policy-based Web service composition that utilizes the semantics associated with the component services.We consider policies imposed by different entities while composing service flows, which include service policies (imposed by the organizations offering component services), service flow policies (associated with the entire service flow), and user policies (the user requirements expressed as policies). In addition to these policies, one may consider rules at the syntactic and semantic levels that can be used to select relevant component services in order to compose customized service flows, by considering the notions of syntactic, semantic and policy compatibility. We model the different policies and the service topic ontology using OWL, DAML-S, RuleML and RDF standards.Recommended by: Athman Bouguettaya and Boualem BenatallahThe work is supported by and a grant from the Meadowlands Environmental Research Institute, New Jersey Meadowlands Commission.     

Solid–liquid expression from denaturated plant tissue: Filtration–consolidation behaviour

The objective of this study is to investigate the filtration–consolidation behaviour of biological tissue (sugar beet specimens), denaturated by pulsed electric field (PEF) and freezing–thawing pretreatments. The degree of cell membrane damage was evaluated by the tissue electrical conductivity measurement (determination of the cell disintegration index Z). The PEF-treated and freeze–thawed tissues show different structure response on the applied compressive pressure and different filtration–consolidation behaviour. The value of fracture pressure (P_f ≈ 58.5 bar) is the lowest and the value of tissue deformation under fracture (ε_f ≈ 0.46) is the highest for sugar beet tissue treated by freezing/thawing. PEF treatment leads to more rigid and more fragile tissue structure (P_f ≈ 63.8 bar, ε_f ≈ 0.28) than freeze–thawed tissue. Untreated tissue seems to be stronger and less fragile than the PEF-treated tissue (P_f ≈ 84.1 bar, ε_f ≈ 0.37). Different tissue reactions on the loading pressure evidently reflect the difference between microstructures of treated and untreated tissues. The filtration/consolidation behaviour during liquid expression from a sugar beet tissue also depends on the type and degree of structure denaturation. Tissues treated by PEF and freezing/thawing demonstrate two consolidation stages of expression (primary and secondary). However, the freeze–thawed tissue tends to modify the expression mechanism under the higher loading pressure (60 bar) with approach to the primary consolidation behaviour. The simplified semi-empirical consolidation model permits a reasonably good prediction of expression behaviour from the denaturated sugar beet tissue and estimation of consolidation coefficient b under different pressures. The extrapolation of curves b(P) shows the value of hypothetical pressure, P_max ≈ 90 bar at which the consolidation behaviour would be similar to both PEF-treated and freeze–thawed tissues.     

Performance of olive waste ash concrete exposed to elevated temperatures

This study explores the influence of olive waste ash (OWA) on the performance of concrete exposed to elevated temperatures in the range from 400 to 600 °C. The performance of concrete to elevated temperature was evaluated using compressive strength and electrical charge of concrete. Three OWA levels were used in the study: 7%, 15%, and 22% by weight of cement. The other experimental parameters investigated in the study were elevated temperature (400 and 600 °C), aggregate type (crushed basalt and volcanic tuff), w/c ratio (0.5 and 0.7), and air content (non-air and air entrained). After the initial moist curing period of 90 days, concrete specimens were exposed to elevated temperatures for a period of 2 h using an electric furnace.     

IoTScal‐H : Hybrid monitoring solution based on cloud computing for autonomic middleware‐level scalability management within IoT systems and different SLA traffic requirements

Wireless sensor network (WSN) technologies have enabled ubiquitous sensing to intersect many areas of modern day living. The creation of these devices offers the ability to get, gather, exchange, and consume environmental measurement from the physical world in a communicating‐actuating network, called the Internet of Things (IoT). As the number of physical world objects from heterogeneous network environments grows, the data produced by these objects raise uncontrollably, bringing a delicate challenge into scalability management in the IoT networks. Cloud computing is a much more mature technology, offering unlimited virtual capabilities in terms of storage capacity and processing power. Ostensibly, it seems that cloud computing and IoT are evolving independently on their own paths, but in reality, the integration of clouds with IoT will lead to deal with the inability to scale automatically depending on the overload caused by the drastic growth of the number of connected devices and/or by the huge amount of exchanged data in the IoT networks. In this paper, our objective is to promote the scalability management, using hybrid mechanism that will combine traffic‐oriented mechanism and resources‐oriented mechanism, with adaption actions. By the use of autonomic middleware within IoT systems, we seek to improve the monitoring components's architectural design, based on cloud computing‐oriented scalability solution. The intention is to maximize the number of satisfied requests, while maintaining at an acceptable QoS level of the system performances (RTT of the system, RAM, and CPU of the middleware). In order to evaluate our solution performance, we have performed different scenarios testbed experiments. Generally, our proposed results are better than those mentioned as reference.     

Enhanced structural and optical properties of ZnO nanopowder with tailored visible luminescence as a function of sodium hydroxide to zinc sulfate mass ratio

ZnO nanopowders of tailored particle sizes were synthesized using a simple wet chemical method, by controlling the mass ratio of the precursors. The physical properties were investigated as a function of OH^?/Zn²⁺ mass ratio (x). The structural properties of the synthesized nanoparticles (NPs) are studied using X-ray diffraction (XRD). XRD patterns show pure wurtzite structure. Microstructural parameters dependence on x ratio was studied based on Williamson-Hall model. We notice an increase in crystallite size (17–24?nm) and a decrease in strain values when the x ratio increases (0.5–1.4). The best crystallinity corresponds to the higher mass ratio. Indeed, for x?=?1.4 we obtain the largest crystallite size, the lowest strain and stacking faults. The TEM images support the XRD results. Raman spectra confirm the purity of the synthesized ZnO powder. Furthermore, the optical properties were examined by UV–vis and Photoluminescence as a function of precursor’s ratio. Absorption data show a band gap red-shift of the ZnO-NPs with increase in particle’s size. Moreover, we found that the ZnO-NPs luminescence in the visible range can be engineered by changes of x ratio. This constitutes an advantage for the use of ZnO-NPs in different wavelength areas in optoelectronic applications covering UV-Blue-Green domain for the LED design, sensors…     

Scalable Substitutional Re-Doping and its Impact on the Optical and Electronic Properties of Tungsten Diselenide

Reliable, controlled doping of 2D transition metal dichalcogenides will enable the realization of next-generation electronic, logic-memory, and magnetic devices based on these materials. However, to date, accurate control over dopant concentration and scalability of the process remains a challenge. Here, a systematic study of scalable in situ doping of fully coalesced 2D WSe₂ films with Re atoms via metal–organic chemical vapor deposition is reported. Dopant concentrations are uniformly distributed over the substrate surface, with precisely controlled concentrations down to <0.001% Re achieved by tuning the precursor partial pressure. Moreover, the impact of doping on morphological, chemical, optical, and electronic properties of WSe₂ is elucidated with detailed experimental and theoretical examinations, confirming that the substitutional doping of Re at the W site leads to n-type behavior of WSe₂. Transport characteristics of fabricated back-gated field-effect-transistors are directly correlated to the dopant concentration, with degrading device performances for doping concentrations exceeding 1% of Re. The study demonstrates a viable approach to introducing true dopant-level impurities with high precision, which can be scaled up to batch production for applications beyond digital electronics.     

Effects of Nanosized PbO and MgO,Rolling, and Sintering Time on Crack and Current Density of Bi1.6Pb0.4Sr2Ca2Cu3O10/Ag Superconductor Tapes

Journal of Superconductivity and Novel Magnetism - The effects of nanoparticle additions, rolling, and sintering time on the transport critical current density, Jc, of Ag-sheathed...