Short fibre elastomer composites: effect of fibre length,orientation, loading and bonding agent

A series of short fibre reinforced styrene butadiene rubber (SBR) composites were prepared by incorporating sisal fibres of different lengths and different concentrations. The vulcanization behaviour and the properties of the vulcanizates were measured by the relevant ASTM procedures. The processing characteristics such as green strength and mill shrinkage were improved by the addition of fibres. The properties like tensile strength, tear strength, moduli at 10% and 20% elongations were found to be maximum for composites containing longitudinally oriented fibres of length 6 mm. Mixes containing 35 phr loading of fibres and bonding agent showed better mechanical performance than others. The failure behaviour of tensile and tear specimens have been analysed by scanning electron microscopy techniques. Paper presented at the poster session of MRSI AGM VI, Kharagpur, 1995     

A study on the moisture sorption characteristics in woven sisal fabric reinforced natural rubber biocomposites

Textile biocomposites were prepared by reinforcing natural rubber with woven sisal fabric. Sisal fabric was subjected to various chemical modifications like mercerization, silanization, and thermal treatment. The moisture uptake of the textile composites was found to depend upon fiber content as well as architecture. The mechanism of diffusion in the composites was found to be fickian in nature. The effect of chemical modification of sisal fabric on moisture uptake was also analyzed. Mercerization was seen to increase the water uptake in the composites while thermally treated fabric reinforced composites exhibited lower water uptake. The influence of temperature on water sorption of the biocomposites is also analyzed. The thermodynamic parameters of the sorption process were also evaluated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 416–423, 2006     

Ageing studies of pineapple leaf fiber–reinforced polyester composites

This experimental study evaluated the water absorption characteristics of pineapple leaf fiber (PALF)–polyester composites of different fiber content. The degree of water absorption was found to increase with fiber loading. The mechanism of diffusion was analyzed and the effect of fiber loading on the sorption kinetics was studied. The diffusion coefficient was calculated and found to increase with fiber content. Studies were also made to correlate water absorption with the cross‐sectional areas of the specimens. The effects of ageing on the tensile properties and dimensional stability of PALF polyester composites were studied under two different ageing conditions. Ageing studies showed a decrease in tensile strength of the composites. The composite specimens subjected to thermal ageing showed only a slight deterioration in strength. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 503–510, 2004     

Moving people tracking with detection by latent semantic analysis for visual surveillance applications

The latent semantic analysis (LSA) has been widely used in the fields of computer vision and pattern recognition. Most of the existing works based on LSA focus on behavior recognition and motion classification. In the applications of visual surveillance, accurate tracking of the moving people in surveillance scenes, is regarded as one of the preliminary requirement for other tasks such as object recognition or segmentation. However, accurate tracking is extremely hard under challenging surveillance scenes where similarity among multiple objects or occlusion among multiple objects occurs. Usual temporal Markov chain based tracking algorithms suffer from the ‘tracking error accumulation problem’. The accumulated errors can finally make the tracking to drift from the target. To handle the problem of tracking drift, some authors have proposed the idea of using detection along with tracking as an effective solution. However, many of the critical issues still remain unsettled in these detection based tracking algorithms. In this paper, we propose a novel moving people tracking with detection based on (probabilistic) LSA. By employing a novel ‘twin-pipeline’ training framework to find the latent semantic topics of ‘moving people’, the proposed detection can effectively detect the interest points on moving people in different indoor and outdoor environments with camera motion. Since the detected interest points on different body parts can be used to locate the position of moving people more accurately, by combining the detection with incremental subspace learning based tracking, the proposed algorithms resolves the problem of tracking drift during each target appearance update process. In addition, due to the time independent processing mechanism of detection, the proposed method is also able to handle the error accumulation problem. The detection can calibrate the tracking errors during updating of each state of the tracking algorithm. Extensive, experiments on various surveillance environments using different benchmark datasets have proved the accuracy and robustness of the proposed tracking algorithm. Further, the experimental comparison results clearly show that the proposed tracking algorithm outperforms the well known tracking algorithms such as ISL, AMS and WSL algorithms. Furthermore, the speed performance of the proposed method is also satisfactory for realistic surveillance applications.     

Natural rubber composites reinforced with sisal/oil palm hybrid fibers: Tensile and cure characteristics

Natural rubber was reinforced with untreated sisal and oil palm fibers chopped to different fiber lengths. The influence of fiber length on the mechanical properties of the hybrid composites was determined. Increasing the fiber length resulted in a decrease in the properties. The effects of concentration on the rubber composites reinforced with sisal/oil palm hybrid fibers were studied. Increasing the concentration of fibers resulted in a reduction in the tensile strength properties and tear strength but an increase in the modulus of the composites. Fiber breakage analysis was evaluated. The vulcanization parameters, processability characteristics, and stress–strain properties of these composites were analyzed. The extent of fiber alignment and the strength of the fiber–rubber interface adhesion were analyzed from the anisotropic swelling measurements. Scanning electron microscopy studies were performed to analyze the fiber/matrix interactions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2305–2312, 2004     

Miscibility studies of polymer blends by viscometry methods

The intrinsic viscosities of blends of poly(vinyl chloride)/poly(ethylene-co-vinyl acetate) (PVC/EVA), poly(vinyl chloride)/poly(styrene-co-acrylonitrile) (PVC/SAN), and poly(ethylene-co-vinyl acetate)/poly(styrene-co-acrylonitrile) (EVA/SAN) have been studied in cyclohexanone as a function of blend composition. In order to predict the compatibility of polymer pairs in solution, the interaction parameter term, Δb, obtained from the modified Krigbaum and Wall theory, and the difference in the intrinsic viscosities of the polymer mixtures and the weight average intrinsic viscosities of the two polymer solutions taken separately are used. © 1994 John Wiley & Sons, Inc.     

Dynamic mechanical behavior of high‐density polyethylene/ethylene vinyl acetate copolymer blends: The effects of the blend ratio,reactive compatibilization,and dynamic vulcanization

The effects of the blend ratio, reactive compatibilization, and dynamic vulcanization on the dynamic mechanical properties of high‐density polyethylene (HDPE)/ethylene vinyl acetate (EVA) blends have been analyzed at different temperatures. The storage modulus of the blend decreases with an increase in the EVA content. The loss factor curve shows two peaks, corresponding to the transitions of HDPE and EVA, indicating the incompatibility of the blend system. Attempts have been made to correlate the observed viscoelastic properties of the blends with the blend morphology. Various composite models have been used to predict the dynamic mechanical data. The experimental values are close to those of the Halpin–Tsai model above 50 wt % EVA and close to those of the Coran model up to 50 wt % EVA in the blend. For the Takayanagi model, the theoretical value is in good agreement with the experimental value for a 70/30 HDPE/EVA blend. The area under the loss modulus/temperature curve (LA) has been analyzed with the integration method from the experimental curve and has been compared with that obtained from group contribution analysis. The LA values calculated with group contribution analysis are lower than those calculated with the integration method. The addition of a maleic‐modified polyethylene compatibilizer increases the storage modulus, loss modulus, and loss factor values of the system, and this is due to the finer dispersion of the EVA domains in the HDPE matrix upon compatibilization. For 70/30 and 50/50 blends, the addition of a maleic‐modified polyethylene compatibilizer shifts the relaxation temperature of both HDPE and EVA to a lower temperature, and this indicates increased interdiffusion of the two phases at the interface upon compatibilization. However, for a 30/70 HDPE/EVA blend, the addition of a compatibilizer does not change the relaxation temperature, and this may be due to the cocontinuous morphology of the blends. The dynamic vulcanization of the EVA phase with dicumyl peroxide results in an increase in both the storage and loss moduli of the blends. A significant increase in the relaxation temperature of EVA and a broadening of the relaxation peaks occur during dynamic vulcanization, and this indicates the increased interaction between the two phases. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2083–2099, 2003     

Effect of layering pattern on dynamic mechanical properties of randomly oriented short banana/sisal hybrid fiber–reinforced polyester composites

Dynamic mechanical test methods have been widely employed for investigating the structures and viscoelastic behavior of polymeric materials to determine their relevant stiffness and damping characteristics for various applications. Randomly oriented short banana/sisal hybrid fiber–reinforced polyester composites were prepared by keeping the volume ratio of banana and sisal 1 : 1 and the total fiber loading 0.40 volume fraction. Bilayer (banana/sisal), trilayer (banana/sisal/banana and sisal/banana/sisal), and intimate mix composites were prepared. The effect of layering pattern on storage modulus (E′), damping behavior (tan δ), and loss modulus (E″) was studied as a function of temperature and frequency. Bilayer composite showed high damping property while intimately mixed and banana/sisal/banana composites showed increased stiffness compared to the other pattern. The Arrhenius relationship has been used to calculate the activation energy of the glass transition of the composites. The activation energy of the intimately mixed composite was found to be the highest. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2168–2174, 2005     

Water quality prediction capabilities of WASP model for a tropical lake system

Water quality modelling facilitates our better understanding of the processes taking place in a lake system, and conservation plans to address them. The water quality analysis simulation programme (WASP) was used in this study to predict daily variations in water quality parameters, namely dissolved oxygen, nitrate, phosphate and chlorophyll‐a and biochemical oxygen demand concentrations in a tropical lake system. The lake was divided into eight segments with the respective morphological, environmental and flow details being model inputs. The monthly concentration of each water quality parameter also comprised model input. The model output was daily spatiotemporal variation in these parameters over a period of 476 days. This study also indicated that the occurrence of precipitation plays a major role in defining the water quality of a tropical lake. The heavy precipitation after a long gap, especially during the summer season, results in a large quantity of organic matter entering the lake through drains, thereby increasing the organic matter and phosphate in the water body, and subsequently resulting in high chlorophyll‐a concentrations in the lake. A reduced chlorophyll‐a concentration was observed during the heavy rains. The water quality fluctuations are more pronounced with precipitation, especially where polluted drains enter the lake. An improved water quality can be observed downstream, including increased dissolved oxygen and nitrate concentrations. Improved water quality was observed during the postmonsoon period, with increased salinity and dissolved oxygen concentrations, a finding that confirms generalized and specific conclusions can be achieved with the use of the WASP model.     

Moving People Segmentation from Zoomed Dynamic Scenes Containing a Door

The challenge of segmenting the moving object is harder when the background is dynamic and the camera used can change its zoom dynamically. Here, in this paper, we propose a method to detect and segment moving object from a dynamic background, which contains moving multiple-leaf doors. In addition, the proposed algorithm also takes care of dynamic zoom changes that can occur while shooting a scene. The proposed method uses background-rebuilding with discrete door’s position to tackle moving multiple-leaf door backgrounds and image feature comparison to tackle changes in zoom. The experiment results show satisfying segmentation results with high processing speed.