Stack cracking by hydrogen embrittlement in a welded pipeline steel

Arrays of cracks, parallel to the original plate rolling direction, were produced in a X65 microalloyed steel by hydrogen embrittlement of pipeline sections containing a weldment. A region of the heat-affected zone of the weldment was shown to have a lower yield strength (soft zone) than the surrounding material and cracking was concentrated in this throughthickness zone to produce the effect known as stack cracking. In situ cathodic hydrogen charging of tensile specimens under load led to failure by linking the rolling-plane cracks with transverse cleavage cracks, which were often initiated at inclusions. All cracking was predominantly by cleavage and failure occurred in tension in short times by hydrogen embrittlement when the applied tensile stress was above about half the uncharged yield stress. The influence of microstructure, hydrogen pressure and tensile loading conditions on the location of stack cracks and the mode of fracture is discussed.     

Large-scale channel characterization at 28 GHz on a university campus in the United Arab Emirates

Telecommunication Systems - Millimeter wave (mm-wave) communication is one of the key enabling technologies for meeting the requirements of the fifth generation (5G) wireless communication systems....     

An intrusion detection and alert correlation approach based on revising probabilistic classifiers using expert knowledge

Bayesian networks are important knowledge representation tools for handling uncertain pieces of information. The success of these models is strongly related to their capacity to represent and handle dependence relations. Some forms of Bayesian networks have been successfully applied in many classification tasks. In particular, naive Bayes classifiers have been used for intrusion detection and alerts correlation. This paper analyses the advantage of adding expert knowledge to probabilistic classifiers in the context of intrusion detection and alerts correlation. As examples of probabilistic classifiers, we will consider the well-known Naive Bayes, Tree Augmented Naïve Bayes (TAN), Hidden Naive Bayes (HNB) and decision tree classifiers. Our approach can be applied for any classifier where the outcome is a probability distribution over a set of classes (or decisions). In particular, we study how additional expert knowledge such as “it is expected that 80 % of traffic will be normal” can be integrated in classification tasks. Our aim is to revise probabilistic classifiers’ outputs in order to fit expert knowledge. Experimental results show that our approach improves existing results on different benchmarks from intrusion detection and alert correlation areas.     

Guest editorial: Advances in RFID technology

After over a half century of development, radio-frequency identification (RFID) is beginning to move into mainstream applications for automatic identification. RFID is widely seen today as one of the key enabling technologies of the “Internet of Things”. However, many challenges still need to be addressed before we can fully benefit from this nascent and ubiquitous technology. In this paper, we present the state of the art of RFID technology and discuss the challenges and open issues in developing next generation RFID applications.     

Experimental Measurement and Thermodynamic Modeling of the Solubility of Carbon Dioxide in Aqueous Alkanolamine Solutions in the High Gas Loading Region

The solubility of carbon dioxide in aqueous alkanolamine solutions was investigated in the high gas loading region based on experimental measurements and thermodynamic modeling. An experimental phase equilibrium study was performed to evaluate the absorption of carbon dioxide in aqueous solutions of five representative alkanolamines, including monoethanolamine, diethanolamine, N-methyldiethanolamine, 2-amino-2-methyl-1-propanol and piperazine. The carbon dioxide loadings of these solutions were determined for a wide range of pressures (62.5 kPa to 4150 kPa), temperatures (303.15 K to 343.15 K) and alkanolamine concentrations (2 M to 4 M). The results were found to be largely consistent with those previously reported in the literature. Furthermore, a hybrid Kent–Eisenberg model was developed for the correlation of the experimental data points. This new model incorporated an equation of state/excess Gibbs energy model for determining the solubility of carbon dioxide in the high-pressure–high gas loading region. This approach also used a single correction parameter, which was a function of the alkanolamine concentration. The results of this model were in excellent agreement with our experimental results. Most notably, this model was consistent with other reported values from the literature.     

Effect of 1-naphthaleneacetic acid on the seed,protein, oil,and fatty acids of egyptian cotton

The effects of 1-naphthaleneacetic acid (NAA) applied at various levels and times on yield, seed index, protein and oil content and fatty acid compositions of cotton plants seeds were studied. NAA increased the seed yield/plant and the seed, protein, and oil yields/ha compared to the control. A level of 20 ppm proved best for yield. Most NAA treatments significantly increased the seed index, but only slight increases in seed protein content were recorded. Increases in the amount of seed oil was moderate, with fluctuation that was due to treatment. NAA generally caused decreases in saturated fatty acids that were associated with increases in unsaturated fatty acids. One treatment proved to be more effective than multiple treatments. Palmitic acid and linoleic acid were the most abundant saturated and unsaturated fatty acids, respectively.     

Polycarbonate/silica nanocomposite membranes: Fabrication,characterization, and performance evaluation

Polycarbonate/silica nanocomposite membranes at low silica loading were fabricated by solution blending and solvent evaporation technique. The functionalized silica nanoparticles used were synthesized by co‐condensing hydrolyzed tetraethylorthosilicate with 3‐aminopropyl trimethoxysilane in the sol–gel process. The membranes morphology, composition, surface, structure, thermal and mechanical properties were analyzed by the standard characterization techniques. The gas permeation tests were conducted in four‐channel permeation cells. Field emission scanning electron microscopy results reveal that membranes above 3 wt % silica content formed distinguishable voids and agglomerates. Fair distribution of silica nanoparticles and absence of residual solvents were observed by energy dispersive X‐ray and thermogravimetric analysis. Fourier transform infrared spectroscopy spectra confirmed the presence of new functional groups (N? H) and (O? H) bonds. The X‐ray diffraction pattern revealed the polymer‐particle interactions, the formation of rigidified polymer chain, and nanostructured silicon crystals. Further, the thermogravimetric analysis results revealed thermal stability enhancement while differential scanning calorimetry results of increased glass transition temperatures confirmed the presence of rigidified polymer chain. Furthermore, enhancements in mechanical strength of the membranes were observed. Moreover, at all feed pressures, increased CO₂, N₂, and CH₄ gas permeation was observed. At 6 bar feed pressure, the CO₂/N₂ and CO₂/CH₄ ideal selectivities of PC membranes with 3 wt % silica loading have increased from 19.2 to 38.0 and 29.2, respectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45310.     

An integrated model for assembly line re-balancing problem

In this paper, an integrated approach for assembly line rebalancing problem (IALRP) is proposed to quickly react and find an optimal rebalancing of the line when disruptive event occurs because of product demand changes. This model is motivated by real-life application of an automotive cable manufacturer which provides more realistic constraints. To solve the problem, we propose a genetic algorithm (GA) hybridised with a heuristic priority rule-based procedure. This hybridisation is used to add more rich seeds to the initial population and consequently to improve the convergence capability and performance of the GA. After the disturbance, we aim to find a rebalance with the proposed approach to maximise the line efficiency and distributing the idle time across the workstations as equally as possible. To evaluate the efficiency of the proposed algorithm, set of samples collected from the literature are used. The real case study and the experiment results show the proposed approach is very effective and competitive.     

Development of kenaf fibre reinforced polymer laminate for shear strengthening of reinforced concrete beam

Fabrication of green fibre composite laminate for strengthening of reinforced concrete structure is one of the current interests in the field of construction industry. The aim of this research was to develop kenaf fibre reinforced polymer (KFRP) laminate for shear strengthening of reinforced concrete beam. Comprehensive design and theoretical models were also proposed for KFRP laminate shear strengthened beam. In the experimental programme, KFRP laminate had been fabricated with various fibre content to obtain optimal mix ratio. Physical and mechanical properties of KFRP laminates were experimentally investigated. Three reinforced concrete beam specimens were prepared for structural investigations. Results showed that KFRP laminate with maximum fibre content had the highest tensile strength and the laminate was found to be elastic isotropic in nature. The KFRP laminate strengthened beam had 100 % higher shear crack load and 33 % ultimate failure load as compared to un-strengthened control beam. It reduced the numbers and width of cracks and had shown strain compatibility behavior with shear reinforcement. The failure load, ductility, crack patterns and strain characteristics of KFRP laminate strengthened beam were found to be closely comparable with CFRP laminate strengthened beam. The experimental results satisfactorily verified the proposed design and theoretical models.