Effects of peroxide crosslinking on the mechanical and morphological properties of poly(ethylene‐co‐vinyl acetate)/zeolite composites

Uncrosslinked and chemically crosslinked ethylene‐vinyl acetate copolymers (EVAs) with 5–25 volume percentages of zeolite were prepared in a melt‐mixing process and then compression‐molded on a hot‐press machine according to standard test specifications. The mechanical properties measured by tensile test showed a reduction in tensile strength and elongation at break with increasing zeolite content. However, an increasing trend was observed for tensile modulus with addition of zeolite. Experimental results for ultimate stress were compared with those from Pukanszky equation. The experimental data showed a good fit to the Pukanszky model. The improvement in the interfacial interaction for crosslinked composites was also confirmed by this model. Morphological changes of EVA/zeolite composites were analyzed by scanning electron microscopy (SEM). The fractured surface of the composites indicated more complex morphology at higher zeolite loading. The influence of crosslinking induced by 2 wt% of dicumyl peroxide on the properties of EVA/zeolite composites was also investigated. The crosslinked composites showed better tensile properties than the uncrosslinked ones, a result which might be an indication of enhanced interaction between the EVA and zeolite. Density measurements, gel content determinations, and Fourier transform infrared analyses were also performed to evaluate the crosslink content of the composites. The changes in the properties of chemically crosslinked EVA/zeolite composites were observed. Meanwhile, SEM micrographs of the crosslinked EVA/zeolite composites showed better interfacial strength between zeolite and the EVA matrix as compared to that of the uncrosslinked composites. J. VINYL ADDIT. TECHNOL., 2012. © 2012 Society of Plastics Engineers     

Phase Transformations of α-Alumina Made from Waste Aluminum via a Precipitation Technique

We report on a recycling project in which α-Al₂O₃ was produced from aluminum cans because no such work has been reported in literature. Heated aluminum cans were mixed with 8.0 M of H₂SO₄ solution to form an Al₂(SO₄)₃ solution. The Al₂(SO₄)₃ salt was contained in a white semi-liquid solution with excess H₂SO₄; some unreacted aluminum pieces were also present. The solution was filtered and mixed with ethanol in a ratio of 2:3, to form a white solid of Al₂(SO₄)₃·18H₂O. The Al₂(SO₄)₃·18H₂O was calcined in an electrical furnace for 3 h at temperatures of 400–1400 °C. The heating and cooling rates were 10 °C/min. XRD was used to investigate the phase changes at different temperatures and XRF was used to determine the elemental composition in the alumina produced. A series of different alumina compositions, made by repeated dehydration and desulfonation of the Al₂(SO₄)₃·18H₂O, is reported. All transitional alumina phases produced at low temperatures were converted to α-Al₂O₃ at high temperatures. The X-ray diffraction results indicated that the α-Al₂O₃ phase was realized when the calcination temperature was at 1200 °C or higher.     

Experiments on Surface Reconstruction for Partially Submerged Marine Structures

Over the past 10 years, significant scientific effort has been dedicated to the problem of three‐dimensional (3‐D) surface reconstruction for structural systems. However, the critical area of marine structures remains insufficiently studied. The research presented here focuses on the problem of 3‐D surface reconstruction in the marine environment. This paper summarizes our hardware, software, and experimental contributions on surface reconstruction over the past few years (2008–2011). We propose the use of off‐the‐shelf sensors and a robotic platform to scan marine structures both above and below the waterline, and we develop a method and software system that uses the Ball Pivoting Algorithm (BPA) and the Poisson reconstruction algorithm to reconstruct 3‐D surface models of marine structures from the scanned data. We have tested our hardware and software systems extensively in Singapore waters, including operating in rough waters, where water currents are around 1–2 m/s. We present results on construction of various 3‐D models of marine structures, including slowly moving structures such as floating platforms, moving boats, and stationary jetties. Furthermore, the proposed surface reconstruction algorithm makes no use of any navigation sensor such as GPS, a Doppler velocity log, or an inertial navigation system.     

Consumer shopping behaviour on the Internet: insights from Malaysia

Shopping on the Internet enables consumers to search for information on products or services and make purchases through direct interaction with online retailers. This study investigates consumer shopping behaviour on the Internet based on four aspects, i.e. the Internet marketing environment, product characteristics, familiarity, and promotional offers. The impact of influencing factors was checked by questionnaire survey, which was then processed and evaluated. Two hundred randomly selected respondents (students and employees in a public higher learning institution in the Federal Territory of Labuan, Malaysia) participated in the survey. Multiple regression analysis was used as a statistical measure to determine the most influential relationship aspect among a series of independent variables of consumer shopping on the Internet. The results revealed that familiarity has a great influence on consumer shopping on the Internet, followed by promotional offers. The assimilation of these aspects, and the empirical examination of the factors that influence consumer shopping on the Internet, advanced understanding of these constructs and their link to dynamic technology deployment for shopping. The paper suggests managerially actionable implications, and future research directions.     

Preparation and characterizations of activated carbon from kenaf fiber for equilibrium adsorption studies of copper from wastewater

The potential of activated carbon prepared from kenaf fiber (KF) to remove copper (II) from aqueous effluents was investigated. The fibers were first semi-carbonized, then impregnated with potassium hydroxide (KOH) and finally activated by using carbon dioxide (CO₂) gas to produce activated carbon. Pore structure and physical characteristics of the prepared kenaf fiber activated carbon (KFAC) were determined. Adsorption studies for divalent copper (Cu) ions were carried out to delineate the effect of contact time, temperature, pH and initial metal ion concentration on equilibrium adsorption capacity. The experimental data followed pseudo-second-order kinetics and Elovich Model than pseudo-first-order. Langmuir, Freundlich and Temkin models were implemented to analyze the parameters for adsorption at 30 °C, 50 °C and 70 °C. Thermodynamic parameters such as ??G ^o , ??H ^o and ??S ^o which represent Gibbs free energy, enthalpy and entropy, respectively, were evaluated. It was concluded that activated carbon from kenaf fiber (KFAC) can be used as an efficient adsorbent for removal of Cu (II) from synthetic wastewater.     

Effect of Synthesis Technique and Carbonate Content on the Crystallinity and Morphology of Carbonated Hydroxyapatite

The syntheses of nanosized carbonated hydroxyapatite（CHA） were performed by comparing dropwise and direct pouring of acetone solution of Ca（N0₃）₂-4H₂0 into mixture of（NH₄）₂HP0₄ and NH₄HCO₃ at room temperature controlled at pH 11.Direct pouring method was later applied to study the increment of carbonate content in syntheses.The as-synthesized powders were characterized by various characterization techniques.The crystallographic results of the produced powders were obtained from X-ray diffraction analysis,whilst the carbonate content in the produced powders was determined by the CHNS/O elemental analyzer.Fourier transform infrared analysis confirmed that the CHA powders formed were B-type.Field emission scanning electron microscopy revealed that the powders were highly agglomerated in nanosized range and hence energy filtered transmission electron microscopy was employed to show elongated particles which decreased with increasing carbonate content.     

Robust hierarchical multiple hypothesis tracker for multiple-object tracking

Multiple object tracking is a fundamental subsystem of many higher level applications such as traffic monitoring, people counting, robotic vision and many more. This paper explains in details the methodology of building a robust hierarchical multiple hypothesis tracker for tracking multiple objects in the videos. The main novelties of our approach are anchor-based track initialization, prediction assistance for unconfirmed track and two virtual measurements for confirmed track. The system is built mainly to deal with the problems of merge, split, fragments and occlusion. The system is divided into two levels where the first level obtains the measurement input from foreground segmentation and clustered optical flow. Only K-best hypothesis and one-to-one association are considered. Two more virtual measurements are constructed to help track retention rate for the second level, which are based on predicted state and division of occluded foreground segments. Track based K-best hypothesis with multiple associations are considered for more comprehensive observation assignment. Histogram intersection testing is performed to limit the tracker bounding box expansion. Simulation results show that all our algorithms perform well in the surroundings mentioned above. Two performance metrics are used; multiple-object tracking accuracy (MOTA) and multiple-object tracking precision (MOTP). Our tracker have performed the best compared to the benchmark trackers in both performance evaluation metrics. The main weakness of our algorithms is the heavy processing requirement.     

Oil palm bunch ripeness classification using fluorescence technique

Oil palm is Malaysia’s major agriculture product and it covers approximately 5 million hectares of Malaysia’s land. Limited land resources have been an important factor that motivated the need to increase oil extraction rate (OER). OER of oil palm fresh fruit bunches (FFB) depends highly on their maturity stage. The ripe oil palm FFB will produce high OER while the under ripe and over ripe oil palm FFB will produce less oil. Thus, this paper presents a method of classification between oil palm FFB into ripe, under-ripe and over-ripe categories. This research was done at an oil palm plantation in peninsular Malaysia. A total of two-hundred and ten oil palm FFB that consist of seventy bunches for each category of under-ripe, ripe and over-ripe had been used. Each bunch was scanned ten times randomly with a hand-held multi-parameter fluorescence sensor called Multiplex®3. The parameter measured was the Blue-to-Red Fluorescence Ratio (BRR_FRF) obtained from blue-green (447 nm) and far-red (685 nm) emission signal by using ultraviolet (UV) light emitting diode as excitation light source. The novel contribution of this research is to prove that the oil palm FFB maturity can be determined using the Blue-to-Red Fluorescence ratio index. This is based to our finding of a significant difference among the three categories of ripeness based on the parameter. Classification and Regression Tree (C&RT) method was proposed in this paper. Hundred-fifty samples were used to develop the model by trained it using C&RT method and the remaining sixty samples for the test component. By using the C&RT method, the results show the best accuracy of overall testing classification is 90%. This research will be useful for future development of non-destructive, automatic and real time oil palm FFB grading system.     

On the Refinement Mechanism of Silicon in Al-Si-Cu-Zn Alloy with Addition of Bismuth

Obtained results of micro and nano studies reveal that bismuth refines the silicon in which the flake silicon changed to lamellar structure with reduction in twin spacing from 160 to 75 nm. Bismuth segregates towards the inter-dendritic regions and decreases the Al-Si contact angle resulting in suppression of the silicon growth causing refinement of the eutectic structure. Increased recalescence temperature and time confirmed that the refinement effect is attributed to the growth stage.     

Do personality problems improve during psychodynamic supportive–expressive psychotherapy? Secondary outcome results from a randomized controlled trial for psychiatric outpatients with personality disorders.

Studies involving patients with personality disorders (PDs) have not focused on improvement of core aspects of the PD. The authors examined changes in quality of object relations, interpersonal problems, psychological mindedness, and personality traits in a sample of 156 patients with Diagnostic and Statistical Manual of Mental Disorders (4th ed.) PD diagnoses being randomized to either manualized or nonmanualized dynamic psychotherapy. Effect sizes adjusted for symptomatic change and reliable change indices were calculated. The authors found that both treatments were equally effective at reducing personality pathology. Only in neuroticism did the nonmanualized group do better during the follow-up period. The largest improvement was found in quality of object relations. For the remaining variables, only small and clinically insignificant magnitudes of change were found. (PsycINFO Database Record (c) 2010 APA, all rights reserved)