HSOP: A neural network paradigm and its applications

This paper presents a neural network paradigm, case studies on its applications and performance. We called this paradigm the Hybrid Sum-of-Products (HSOP), and it is an improvement on both sum-of-products and backpropagation paradigms. In the HSOP architecture, the lowest layer (input layer) is connected to the layer above in the standard backpropagation manner. Subsequent layers are connected in the sum-of-products manner. The learning rates required for the HSOP are similar to those required for sum-of-products, with slight differences. Since input units do not have defined error, the fact that they are connected differently has no consequences on the calculations of the error and values for the rest of the units. The proposed paradigm was applied to two classification problems: computer user identification and characterisation of ultrasonic transducers. In both cases, the HSOP showed faster learning than backpropagation and sum-of-products without a significant computational penalty, since the number of its weights is comparable to backpropagation. The classification accuracy of HSOP when applied to the two applications is better than the traditional sum-of-products, and is comparable to that of the backpropagation.     

Continuously operating reference station and surveying applications in KSA

Recently, there is an increased interest in surveying applications based on Continuously Operating Reference Station (CORS) technology in the Kingdom of Saudi Arabia (KSA). Jeddah Municipality has started operating the first CORS network in KSA since 2007. This work discusses the new technologies used in Jeddah CORS network, the obtained accuracy and addresses, the different applications covered by CORS network such as cadastral surveying, road surveying, Lidar, among others. Moreover, the work presents the determination of the different transformation parameters between ITRF/WGS84 coordinate system and the local coordinate systems used in KSA. The purpose is to improve the communication abilities in order to operate modern smart cities. With full coverage and high accuracy of locations, Geographic Information System (GIS) and 3D models will be created to operate all aspects of life starting from the inside (the houses) and ending with saving the environment and the energy. Copyright © 2015 John Wiley & Sons, Ltd.     

RC beams strengthened with composite material: a limit analysis approach and experimental study

This paper deals with the flexural strengthening of reinforced concrete beams by means of thin carbon fibre reinforced plastic (CFRP) plates. A simplified laminated plate model is used to describe the behaviour of three-layered plate in cylindrical bending which were subjected to third-point line loads. The upper bound theorem of limit analysis is used to approximate the ultimate load capacity for multi-layered plates and identify different collapse mechanisms. A reinforced concrete beam strengthened by CFRP is designed as a three-layered plate. Experimental results are obtained and a comparison with theoretical predictions made.     

Alumina-zirconia machinable abutments for implant-supported single-tooth anterior crowns

Innovative materials and application techniques are constantly being developed in the ongoing search for improved restorations. This article describes a new material and the fabrication process of aesthetic machinable ceramic anterior implant abutments. The ceramic material utilized is a mixture of alumina (aluminum oxide) and ceria (cerium oxide) with partially stabilized zirconia (zirconium oxide). The initial core material is a cylinder with a 9-mm diameter and a 15-mm height, obtained by ceramic injection and presintering processes. The resultant alumina-zirconia core is porous and readily machinable. It is secured to the analog, and its design is customized by machining the abutment to suit the particular clinical circumstances. The machining is followed by glass infiltration, and the crown is finalized. The learning objective of this article is to gain a basic knowledge of the fabrication and clinical application of the custom machinable abutments.     

A simple multi-wave algorithm for the uncapacitated facility location problem

The multi-wave algorithm (Glover, 2016) integrates tabu search and strategic oscillation utilizing repeated waves (nested iterations) of constructive search or neighborhood search. We propose a simple multi-wave algorithm for solving the Uncapacitated Facility Location Problem (UFLP) to minimize the combined costs of selecting facilities to be opened and of assigning each customer to an opened facility in order to meet the customers’ demands. The objective is to minimize the overall cost including the costs of opening facilities and the costs of allocations. Our experimental tests on a standard set of benchmarks for this widely-studied class of problems show that our algorithm outperforms all previous methods.     

Removal of copper(II) from aqueous phase by Purolite C100-MB cation exchange resin in fixed bed columns: modeling

The dynamic removal of copper by Purolite C100-MB cation exchange resin was studied in packed bed columns. The values of column parameters are predicted as a function of flow rate and bed height. Batch experiments were performed using the Na-form resin to determine equilibrium and kinetics of copper removal. The uptake of Cu(II) by this resin follows first-order kinetics. The effect of stirring speed and temperature on the removal kinetics was studied. The activation energy for the exchange reaction is 13.58kJmol(-1). The equilibrium data obtained in this study have been found to fit both the Langmuir and Freundlich isotherm equations. A series of column tests were performed to determine the breakthrough curves with varying bed heights and flow rates. To predict the breakthrough curves and to determine the characteristic parameters of the column useful for process design, four kinetic models; Bohart-Adams, Bed Depth Service Time (BDST), Clark and Wolborska models are applied to experimental data. All models are found suitable for describing the whole or a definite part of the dynamic behavior of the column with respect to flow rate and bed height. The simulation of the whole breakthrough curve is effective with the Bohart-Adams and the Clark models, but the Bohart-Adams model is better. The breakthrough is best predicted by the Wolborska model. The breakthrough data gave a good fit to the BDST model, resulting in a bed exchange capacity very close to the value determined in the batch process.     

Kinetic study of hindered amine light stabilizer photografting in low density polyethylene films under natural weathering conditions

The photografting kinetic of a hindered amine light stabilizer (HALS) was studied in low density polyethylene (LDPE) films under natural weathering conditions. The HALS (PBH‐3) was added to the polymer at a concentration of 0.3% (w/w). The photografting kinetic of polymer bound HALS (PBH‐3) was determined by direct spectroscopic measurements through the absorption band area of the stabilizer centered at 308 nm in the UV spectra and 1605 cm^?1 in Fourier transform IR (FTIR) spectra, which correspond to benzylidene malonate ester and benzylidene malonic groups, respectively. In parallel, measurements were carried out on the free PBH‐3 content after chloroform extraction of the photostabilizer from the polymer matrix by means of UV and gas chromatography methods. The results showed that in natural weathering the grafting of PBH‐3 occurred in the LDPE film after very short exposure times of 127 and 168 h as determined by UV and FTIR, respectively. Moreover, the curves describing both the photografting and the free HALS kinetics exhibited similar profiles. The mechanism of photografting implies a rapid photoreaction between the methylenic double bond of the stabilizer and the macroalkyl radicals of the polymer, resulting in formation of polymer‐bonded aminyl derivatives of the stabilizer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1524–1532, 2002; DOI 10.1002/app.10492     

Study of the Effects of Gamma Irradiation on the Structure and Physical Properties of Low Density Polyethylene Films Containing Hindered Amine Stabilizers

The effect of gamma‐irradiation on the structure, rheology, and mechanical properties of low density polyethylene (LDPE) films containing some new hindered amine stabilizers (HAS) has been investigated and the results obtained were compared to additive free samples. The HAS used involved various structures such as an alkoxyamine, a polymer bound HAS and a HAS modified with siloxane; these are commercially known as Tinuvin 123, Sanduvor PR 31 and Uvasil 299, respectively. It was found that the carbonyl index values measured by FTIR spectroscopy increased linearly with the radiation dose for all the samples studied, however this increase was less pronounced for the stabilized samples. The formation rates of carbonyls followed the order LDPE > LDPE/Uvasil 299 > LDPE/PR 31 > LDPE/Tinuvin 123. The second order derivative UV analysis showed the formation of vinyl groups in the irradiated samples at higher doses (812 kGy), while vinylidene groups were detected only in the films stabilized with PR 31 and Tinuvin 123. The curves of the melt flow rate (MFR) exhibited a fast increase for the unstabilized sample after 67 kGy, indicating the occurrence of chain scission. The stabilized samples on the other hand showed an evident increase in MFR from almost 300 kGy. The contribution of different HAS for the durability of LDPE films under γ rays was evaluated by determining the half‐value‐dose, which is related to the radiation resistance of the material. The results indicated that the presence of HAS in LDPE films improves the half‐value‐dose of those stabilized with Tinuvin 123 by 2.5 times against 2.4 and 2 for PR 31 and Uvasil 299, respectively. These data correlate well with the results obtained by FTIR and MFR measurements. Finally, the higher efficiency of Tinuvin 123 could be assigned to its appropriate oxidation state to enter the stabilization mechanism directly.

An example of the new HAS.