Properties of fatty-acid esters of starch

This work examines the properties of starch esters for their possible application as environmentally degradable thermoplastics. The rheological, thermal, and mechanical properties of a series of fatty-acid esters of high-amylose starch (as well as the effects of adding plasticizer on some selected properties) were evaluated. The ester group acts like an internal plasticizer, with an increase in the size of the fatty-acid chain, resulting in greater internal plasticization. This is reflected in the rheological and thermal measurements as well as in the mechanical properties. Overall, larger ester groups and the addition of external plasticizer make these starch-based materials more processable and more ductile. However, comparing their properties and cost to commodity thermoplastics leads us to believe that their commercial applications are likely to be limited, at least in the near future. © 1995 John Wiley & Sons, Inc.     

A new image binarization method using iterative partitioning

This paper proposes a new method for image binarization that uses an iterative partitioning approach. The proposed method has been tested towards binarization of both document and graphic images. The quantitative comparisons with other standard methods reveal that the proposed approach outperforms existing widely used binarization techniques in terms of accuracy of binarization. The experimental results further establish the superiority of the proposed method, especially for degraded documents and graphic images. The proposed algorithm is suitable for a multi-core processing environment as it can be split into multiple parallel units of executions after the initial partitioning.     

Granulometric analyses of basin‐wise DEMs: a comparative study

Digital elevation models (DEMs) are very useful for terrain characterization. We apply a morphological approach to characterize 14 sub‐basins decomposed from interferometrically generated DEMs of Cameron Highlands and Petaling regions of Peninsular Malaysia. Physiographically, these two regions possess a distinct geomorphologic set‐up as they belong to region with higher and lower altitudes, respectively. Fourteen sub‐basins are extracted from the DEMs, and pattern spectra by opening and closing of these sub‐basins relative to flat discrete binary patterns (square, octagon and rhombus) are computed. Pattern spectra are used to compute probability size distribution functions of both protrusions and intrusions that are conspicuous in topography, based on which shape‐size complexity measures of these sub‐basins are estimated by means of average roughness and size. Furthermore, fractal dimensions of channel networks derived from these 14 basins are computed by applying the box‐counting method. Comparisons between shape‐size complexity measures and fractal dimension are carried out.     

Estimation of number-area-frequency dimensions of surface water bodies

This paper proposes a technique that includes a set of mathematical morphological transformations to estimate the frequency dimension. The dimension computed through a power law relationship is tallied with the dimension computed through a correlational plot. This technique is demonstrated on a two-dimensional section embodying a large number of surface water bodies, extracted from remotely sensed data, situated randomly, and the frequency dimension (D) for surface water bodies yields straight-line dependence of lnC(r) (correlational integral) on ln(r) (radius of structuring template). The correlational integral is computed for two aspects by considering the number of water bodies and their corresponding occupied areas. The number-frequency dimension and the area frequency dimension computed through correlational plots yield straight-line dependencies with slopes that are greater than unity but less than 2.0 (1.3 and 1.7, respectively).     

Neural networks and their applications in component design data retrieval

Neural networks have gained increased importance in the past few years. One of the basic characteristics of neural networks is the property of associative memory. In this paper we study the possibility of using the ideas of neural networks and associative memory in the manufacturing domain, with specific reference to design data retrieval in group technology. A two-layer feed-forward perceptron with backpropagation is simulated on a Vax-8550 to train example parts. The complete scheme along with the simulation results are explained and future directions indicated.     

Dielectric properties of EVA/LDPE TPE system: Effect of nanosilica and controlled irradiation

The pristine nanosilica particles were melt‐blended with a model low‐density polyethylene–ethylene vinyl acetate thermoplastic elastomers (TPE) system by varying the sequence of addition and nanosilica contents. Bis‐[3‐(triethoxysilyl)propyl] tetrasulfide (Si‐69) was used to improve the state of dispersion of nanosilica particles in one of the compositions. The dielectric properties of the TPE systems are influenced remarkably by loadings of silica, variation of sequence of addition of ingredients during mixing, addition of Si‐69, and controlled electron beam irradiation. The effects of interfacial and orientation polarization on the permittivity and the loss tangent were studied by dielectric analyses. These were correlated with the structures of various nanocomposites. An attempt has also been made to support the dielectric results by volume resistivity measurements, measurements of breakdown voltage, and swelling–deswelling kinetic results. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

Optimization of fused filament fabrication process parameters for mechanical responses of weather-resistant polymer (acrylonitrile styrene acrylate)

Additively manufactured polymeric products for automotive, aerospace, and biomedical applications are usually intended for service in an outdoor environment with high mechanical loading conditions. The strength and sustainability of the products can be significantly degraded due to the outdoor environmental conditions such as UV light, moisture, heat, and so forth. In this research work, a novel weather-resistant polymer (WRP) material, that is, acrylonitrile styrene acrylate (ASA), has been studied. Furthermore, this work aims to study the effect of process parameters and enhance the strength of WRP (ASA) specimens using the FFF process. The optimized process parameters, that is, build orientation (BO), extrusion temperature (ET), layer thickness (LT), and printing speed (PS), were identified based on the tensile and flexural strength using the Taguchi technique and statistical analysis. The best tensile and flexural strengths for the specimen were achieved at both orientations (XYZ and ZXY) TS: 255°C ET, 0.14 mm LT, 50 mm/s PS; and FS: 245°C ET, 0.28 mm LT, 50 mm/s PS, respectively. Regression model was developed to investigate the correlation between the process parameters with tensile and flexural strength. A validation test confirmed the findings, and the error between the actual and predicted values is less than ±10%.     

Non-destructive evaluation of mechanical properties of poly (vinyl) alcohol-hydroxyapatite nanocomposites

Hydroxyapatite-poly (vinyl) alcohol nanocomposite powder was synthesized using varying poly (vinyl) alcohol concentrations. The dried powder was compacted into micro-porous disks at a load of 4 tons. The disks were sintered at 1200°C to evolve porous nanocomposites. Size and shape of the pores observed in the scanning electron micrographs were quantified by using image processing software. Ultrasound velocity measurements were done to evaluate mechanical properties non-destructively.