The polymerization mechanism of methylol-functional benzoxazine monomers is reported using a series of monofunctional benzoxazine monomers synthesized via a condensation reaction of ortho-, meta-, or para-methylol–phenol, aniline, and paraformaldehyde following the traditional route of benzoxazine synthesis. A phenol/aniline-type monofunctional benzoxazine monomer has been synthesized as a control. The structures of the synthesized monomers have been confirmed by ¹H NMR and FT-IR. The polymerization behavior of methylol monomers is studied by DSC and shows an exothermic peak associated with condensation reaction of methylol groups and ring-opening polymerization of benzoxazine at a lower temperature range than the control monomer. The presence of methylol group accelerates the ring-opening polymerization to give the ascending order of para-, meta-, and ortho-positions in …

Fuzzy decision forests aim to improve the predictive power of single fuzzy decision trees by allowing multiple views of the same domain to be modelled. Such forests have been successfully created for classification problems where the outcome field is discrete; however predicting a continuous output value is more challenging in combining the output from multiple fuzzy decision trees. This paper presents a new approach to creating fuzzy regression tree forests based upon the induction of multiple fuzzy regression decision trees from one training sample, where each tree will represent a different view of the data domain. The singular fuzzy regression trees are induced using a proven algorithm known as Elgasir which fuzzifies crisp CHAID decision trees using trapezoidal membership functions for fuzzification and applies Takagi-Sugeno inference to obtain the final predicted values. A modified version of Artificial Immune System Network model (opt-aiNet) is then used for the simultaneous optimization of the membership functions across all trees within the forest. A strength of the proposed method is that data does not require fuzzification before forest induction this reducing pre-processing time and the need for subjective human experts. Five problem sets from the UCI repository and KEEL repository are used to evaluate the approach. The experimental results have shown that fuzzy regression tree forests reduce the error rate compared with single fuzzy regression trees. 

Numerical simulations have been carried out for highly under-expanded jet from an accidental release of high-pressure hydrogen–oxygen mixture into the atmospheric pressure by using KIVA-3V software. The original KIVA-3V [1] solves 3-D unsteady transport equations of a turbulent, and the chemically reactive mixture of gases. The gas phase solution procedure is based on a finite volume method called ALE (Arbitrary Lagrangian-Eulerian) method. A shock structure from the under-expansion is numerically resolved in a small computational domain above the jet exit. In this paper the investigate of a high pressure jet (30 MPa) of hydrogen-oxygen mixture by using a directed numerical simulation have been conducted. A small hole of 2 mm is assumed to be opened on the wall of a tank and a chocked mixture is injected to air. The autoigniton of pressurized hydrogen-oxygen mixture was predicted to first take place downstream of the Mach dick as the mixture heated to self-ignition temperature. Such knowledge is valuable for studying the ignition characteristics of high-pressure hydrogen jets in the safety context.

In this paper we study the use of the Brill tagger [5,6,7] for tagging Modern Standard Arabic (henceforth MSA) text. The Brill tagger is a famous public domain part of speech tagger, originally designed for tagging English text by implementing machine learning approach through the method of transformation rules. IT had been adopted for other languages by many researchers [17,19,22]. Some modifications are needed on the learner and tagger that are written partly in perl and partly in C programming languages, and are run under the unix/linux operating system. The main change is done on the initial state tagger, which is used by both learner and tagger. A program is written using the lexical analyzer Lex to capture Arabic morphological structures, and then interfaced with both learner and tagger. The tagset used in this work is a revised version of that introduced by Khoja [11]. The revision included changing some of the tags for linguistic considerations and introducing some new tags to make the set more powerful, or to make up for limitations in the original tagset that hinder tagging some words. The corpus is obtained from two Jordanian magazines, and has to go through a series of editing steps. A collection of lexical rules and contextual rules are obtained and applied to Arabic text. The tagging accuracy of the resulting tagged text is measured now to be an average of up to about 84% for both known and unknown words, A rate, which is very promising for such a complex language and rich tagset. We still hope for better performance.

Abstract

The paper presents studies on numerical modelling of beam-to-column joint behaviour in typical service and exceptional design situations. The complexity of such investigations arises from highly nonlinear effects associated with the prediction of joint performance, such as structural imperfections, large displacements and rotations, inelastic properties of steel and concrete, bonding effects between steel and concrete, and slip between concrete and structural steel, among others. The paper addresses these problems and provides validation of numerical modelling techniques trough comparison with experimental data for joints under hogging and sagging moments. © (2012) Trans Tech Publications.

Increasing concern for environment has made building owners and designers to incorporate green design into their building projects. Buildings take about 40 per cent of energy consumption globally and have significant impact on the productivity and wellbeing of the occupants. However, the quality of design team attributes the quality of clients and the characteristics of the building projects have been argued to be the main factors that determine the green design performance of buildings. Therefore, the main objectives of this study are to measure the green design building performance, the quality of client and the attributes of the design team. This study also measures the extent to which the quality of design team attributes, the quality of clients and the characteristics of the building projects affect the green design performance of buildings.The study adopted a triangulation technique that combined both quantitative and qualitative methods of data collection.