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Microstructural Properties (microstructural + property)
Selected AbstractsTEXTURAL AND MICROSTRUCTURAL PROPERTIES OF BURFI MADE WITH VARIOUS SWEETENERSJOURNAL OF TEXTURE STUDIES, Issue 6 2007S. ARORA ABSTRACT High-intensity low-calorie sweeteners saccharin, acesulfame-K, sucralose and aspartame were used as a replacement for sucrose in the manufacture of burfi. Burfi sweetened with low-calorie sweeteners ranked lower (P < 0.05) but was still acceptable in various textural attributes at all periods of storage in comparison to the control with sucrose. The low hardness, adhesiveness, springiness and accordingly, gumminess and chewiness in burfi samples sweetened with low-calorie sweeteners were because of the lack of compactness. It was evident from the scanning electron microscopy that the compactness of the network in burfi decreased with the use of low-calorie sweeteners. The results of the sensory evaluation have shown the successful use of low-calorie sweeteners in the preparation of burfi with a slight difference in its overall acceptability, thus providing an alternate variety to the health-conscious consumers. PRACTICAL APPLICATIONS The consumption of sweets is an integral part of the Indian dietary system. An estimated 54% of India's milk production is converted into products, both traditional and western, with 50% share of traditional products. But in recent years, the manufacturers are diversifying the production to include the specialty items that cater to specific targeted populations. Diabetic-friendly traditional sweet is a new category for such products, the production of which is being contemplated by many enterprising manufacturers. The results have shown the possibility of using low-calorie sweeteners in the preparation of indigenous dairy products, i.e., burfi. The manufacture of indigenous dairy products with low-calorie sweeteners will provide a successful outlet for traditional milk products, and this will provide an alternate variety to the health-conscious consumers. [source] A Study of the Influence of Composition on the Microstructural Properties of ZnO/Al2O3 Mixed Oxides,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 7 2009Shaojun Miao Abstract A series of ZnO/Al2O3 mixed oxide samples with varyingZn/Al ratio is prepared by coprecipitation, ageing, drying, and calcination. Samples are investigated in the state after drying and calcination. The applied methods include X-ray diffraction, solid-state 27Al magic-angle spinning nuclear magnetic resonance spectroscopy, transmission electron microscopy and thermogravimetric experiments coupled with evolved gas analysis. Phases present in the dried precursor samples include hydrozincite, zaccagnaite, and an unknown phase. After calcination zinc oxide and spinel can be found. All results indicate the substitution of Al ions for Zn ions in zinc oxide of zinc-rich samples. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Site-Specific Deterioration of Trabecular Bone Architecture in Men and Women With Advancing AgeJOURNAL OF BONE AND MINERAL RESEARCH, Issue 12 2008Eva-Maria Lochmüller Abstract We tested the hypothesis that the age dependence of trabecular bone microstructure differs between men and women and is specific to skeletal site. Furthermore, we aimed to investigate the microstructural pattern of bone loss in aging. Microstructural properties of trabecular bone were measured in vitro in 75 men and 75 age-matched women (age, 52,99 yr) using ,CT. Trabecular bone samples were scanned at a 26-,m isotropic resolution at seven anatomical sites (i.e., distal radius, T10 and L2 vertebrae, iliac crest, femoral neck and trochanter, and calcaneus). DXA measurements were obtained at the distal radius and proximal femur and QCT was used at T12. No significant decrease in bone density or structure with age was found in men using ,CT, DXA, or QCT at any of the anatomical sites. In women, a significant age-dependent decrease in BV/TV was observed at most sites, which was strongest at the iliac crest and weakest at the distal radius. At most sites, the reduction in BV/TV was associated with an increase in structure model index, decrease in Tb.N, and an increase in Tb.Sp. Only in the calcaneus was it associated with a significant decrease in Tb.Th. In conclusion, a significant, site-specific correlation of trabecular bone microstructure with age was found in women but not in men of advanced age. The microstructural basis by which a loss of BV/TV occurs with age can vary between anatomical sites. [source] An upscaling method and a numerical analysis of swelling/shrinking processes in a compacted bentonite/sand mixtureINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 15 2004M. Xie Abstract This paper presents an upscaling concept of swelling/shrinking processes of a compacted bentonite/sand mixture, which also applies to swelling of porous media in general. A constitutive approach for highly compacted bentonite/sand mixture is developed accordingly. The concept is based on the diffuse double layer theory and connects microstructural properties of the bentonite as well as chemical properties of the pore fluid with swelling potential. Main factors influencing the swelling potential of bentonite, i.e. variation of water content, dry density, chemical composition of pore fluid, as well as the microstructures and the amount of swelling minerals are taken into account. According to the proposed model, porosity is divided into interparticle and interlayer porosity. Swelling is the potential of interlayer porosity increase, which reveals itself as volume change in the case of free expansion, or turns to be swelling pressure in the case of constrained swelling. The constitutive equations for swelling/shrinking are implemented in the software GeoSys/RockFlow as a new chemo-hydro-mechanical model, which is able to simulate isothermal multiphase flow in bentonite. Details of the mathematical and numerical multiphase flow formulations, as well as the code implementation are described. The proposed model is verified using experimental data of tests on a highly compacted bentonite/sand mixture. Comparison of the 1D modelling results with the experimental data evidences the capability of the proposed model to satisfactorily predict free swelling of the material under investigation. Copyright © 2004 John Wiley & Sons, Ltd. [source] Effect of different starches on rheological and microstructural properties of (II) commercial processed cheeseINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 12 2008Darshan Trivedi Summary A range of commercial processed cheese samples containing starch were prepared on a Rapid Visco Analyser (RVA) and on a pilot plant scale. This work clearly demonstrated that it was possible to manufacture processed cheese with part of the protein replaced with potato starch, while maintaining similar rheological attributes (firmness) to those of the control and an acceptable melt index. Sensory evaluation showed that, although the reduced-protein cheese samples had a good, clean, fresh flavour that was comparable with that of the control, at high starch concentrations the starch-containing processed cheese had a pasty texture and tended to stick to the wrapper. [source] Microwave and convective dehydration of ethanol treated and frozen apple , physical properties and drying kineticsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 6 2002Tomas Funebo The objective of this study was to examine how the drying kinetics and physical properties of apples are affected by pre-treatment with 95% ethanol or freezing at ,18 °C before microwave-assisted air dehydration at 50, 60 and 70 °C. Microwave heating was used to obtain these temperatures in the centre of the apple cubes. After dehydration the shrinkage and rehydration capacity were measured. The texture of dehydrated and rehydrated samples was analysed with a puncture test in a texture analyser. Samples were also analysed with confocal laser scanning microscopy to determine the correlation between physical and microstructural properties. Diffusivity in the different dehydration processes was calculated. Ethanol-treated apples showed both high rehydration and high effective rehydration capacity compared with the other samples. Freezing before dehydration increased the diffusivity and reduced the firmness of rehydrated apples compared with no pre-treatment. [source] Anthropological and physicochemical investigation of the burnt remains of Tomb IX in the ,Sa Figu' hypogeal necropolis (Sassari, Italy) , Early Bronze AgeINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 2 2008G. Piga Abstract Excavations carried out in Tomb IX of the hypogeic necropolis of ,Sa Figu', near the village of Ittiri (Sassari, Italy), supplied burnt human bone remains and pottery unambiguously referred to the Early Bronze Age (characterised by the local culture of ,Bonnannaro'). Besides the anthropological study, we have investigated and evaluated the possibility of a funerary cremation practice in Sardinian pre-history, a subject that has previously not been considered from a scientific point of view. Making use of a calibration procedure based on X-ray diffraction (XRD) line-broadening analysis, related to the microstructural properties, it was possible to estimate the combustion temperature to which the fragmented bones were subjected. It was found that the studied bones reached temperatures varying from 400°C up to a maximum of 850°C. This spread of values suggested inhomogeneous combustion of the bones, which seems compatible with funerary cremation practices. Copyright © 2007 John Wiley & Sons, Ltd. [source] Nanofiber organic semiconductors: The effects of nanosize on the electrical charge transport and optical properties of bulk polyanilinesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2009F. Yakuphanoglu Abstract The electrical transport, optical, and microstructural properties of bulk polyaniline (PANI) and nano-PANIs were investigated. A field emission scanning electron microscopy (SEM) image of bulk PANI showed macroscopic and aggregated granular particles. A SEM image of the nanostructured PANI showed the formation of one-dimensional nano/microstructures. The formation of nanofibers was observed from the transmission electron microscopy image. The electrical conductivities of the bulk and nanostructured PANIs increased with increasing temperature, which indicated semiconductor behavior. The electrical conductivities of the bulk and nanostructured PANIs at room temperature were found to be 2.12 × 10,5 and 1.80 × 10,2 S/cm, respectively. The electrical conductivity of the nanostructured PANI was about 850 times higher than that of the bulk PANI. The obtained band gaps of the bulk and nanostructured PANIs were determined from diffuse reflectance measurements and were found to be 3.27 and 2.41 eV, respectively. The refractive index of the PANI samples changed from 1.3 to 1.61. The obtained results indicate that the electrical and optical properties of the PANI were inherently dependent on the nanostructure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Relaxation Time Spectrum of Hydrogels by CONTIN AnalysisJOURNAL OF FOOD SCIENCE, Issue 3 2000R. Mao ABSTRACT: CONTIN is a general-purpose program for inverting noisy linear algebraic and integral equations by means of inverse Laplace transform. This study explored the application of CONTIN analysis to determine the relaxation time distribution spectra for food gels, including gellan, carrageenan, whey protein, and gelatin gels, based on stress-relaxation data. CONTIN results represent the continuous relaxation time spectra when the number of the terms in the discrete Maxwell stress-relaxation model approached infinity. The CONTIN results for gellan gels were correlated to the texture properties of gels from compression tests with respect to the effects of calcium concentrations. CONTIN analysis may be a very effective tool in elucidating the microstructural properties of a hydrogel from mechanical testing. [source] Age, gender, and bone lamellae elastic moduliJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2000C. E. Hoffler To enhance preventative and therapeutic strategies for metabolic bone diseases and bone fragility disorders, we began to explore the physical properties of bone tissue at the cellular level. Proximal femurs were harvested from 27 cadavera (16 male and 11 female) for in vitro measurement of the mechanical properties. We measured the variations in lamellar-level elastic modulus and hardness in human bone as a function of age and gender to identify microstructural properties responsible for age and gender-related reductions in the mechanical integrity. The lateral femoral necks were examined, and age, gender, height, body mass, and body mass index were not found to correlate with lamellar-level elastic modulus or hardness. This result was consistent for osteonal, interstitial, and trabecular tissue. These data suggest that increased bone mass maintenance, known to occur in heavier individuals, is not accompanied by increases in the lamellar-level elastic modulus or hardness. The independence of elastic modulus and hardness from age and gender suggests that age and gender-related decreases in mechanical integrity do not involve alterations in elastic modulus or hard ness of the extracellular matrix. Lamellar-level ultimate, fatigue, and fracture toughness properties should also be investigated. Other factors, such as tissue mass and organization, may also contribute to age and gender-related decreases in the mechanical integrity. [source] RHEOLOGICAL PROPERTIES, WHEY SEPARATION, AND MICROSTRUCTURE IN SET-STYLE YOGURT: EFFECTS OF HEATING TEMPERATURE AND INCUBATION TEMPERATUREJOURNAL OF TEXTURE STUDIES, Issue 5-6 2003WON-JAE LEE The effects of heat treatment and incubation temperature on the rheological and microstructural properties of yogurt were studied. A central composite experimental design and response surface methodology were used for data analysis. The rheological properties were determined by dynamic low amplitude oscillation and the amount of spontaneous whey separation was quantified by the volumetric flask test. Confocal scanning laser microscopy was used to examine the gel structure. The storage moduli of yogurts increased with an increase in heating temperature and a decrease in incubation temperature. The maximum loss tangent value during gelation, permeability, and amount of spontaneous whey separation of yogurts increased with a decrease in heating temperature and with an increase in incubation temperature. These parameters indicated an increased possibility for rearrangements, which was confirmed by presence of large pores in the gel network. Second order polynomial models successfully predicted the effects of heating temperature and incubation temperature on the rheological properties, permeability, and whey separation of yogurts. Whey separation was negatively correlated with storage modulus (r= -0.66), and was positively correlated with the maximum loss tangent (r= 0.63) and permeability (r= 0.78). This study demonstrates that weak yogurt gels, which have high loss tangent values, favor rearrangements in the network and the resulting network has larger pores (high permeability) and exhibits greater whey separation. [source] Diffusion-weighted MRI measurements on stroke patients reveal water-exchange mechanisms in sub-acute ischaemic lesionsNMR IN BIOMEDICINE, Issue 6 2009J. Lätt Abstract The aim of this study was to investigate the diffusion time dependence of signal- versus - b curves obtained from diffusion-weighted magnetic resonance imaging (DW-MRI) of sub-acute ischaemic lesions in stroke patients. In this case series study, 16 patients with sub-acute ischaemic stroke were examined with DW-MRI using two different diffusion times (60 and 260,ms). Nine of these patients showed sufficiently large lesions without artefacts to merit further analysis. The signal- versus - b curves from the lesions were plotted and analysed using a two-compartment model including compartmental exchange. To validate the model and to aid the interpretation of the estimated model parameters, Monte Carlo simulations were performed. In eight cases, the plotted signal- versus - b curves, obtained from the lesions, showed a signal,curve split-up when data for the two diffusion times were compared, revealing effects of compartmental water exchange. For one of the patients, parametric maps were generated based on the extracted model parameters. These novel observations suggest that water exchange between different water pools is measurable and thus potentially useful for clinical assessment. The information can improve the understanding of the relationship between the DW-MRI signal intensity and the microstructural properties of the lesions. Copyright © 2009 John Wiley & Sons, Ltd. [source] Effect of V addition on magnetic, transport, and microstructural properties of La0.7Sr0.3MnO3PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2008T.-S. Zhao Abstract The microstructural, magnetic, and magnetotransport properties of polycrystalline samples with nominal composition of La0.7Sr0.3Mn1,xVx O3 (0 , x , 0.25) sintered in air have been investigated. It is found that V could not substitute for Mn to form La0.7Sr0.3Mn1,xVx O3. The samples contain several phases such as (La, Sr)Mn1,,O3, LaSr3V3O12, Mn3O4 etc. and constitute multi-phase composites. The Sr,V-rich phase form a liquid phase during sintering process and the sintering be long to liquid-phase sintering, which may effectively promote grain growth of (La, Sr)Mn1,,O3 phase. The Curie temperature TC and saturation magnetization of the composites decrease with increasing the V content x. The addition of V may effectively improve the low-field MR response at low temperatures due to the variation in the microstructure of the composites. The MR ratio at a low field of 2 kOe reaches 25% for the x = 0.15 sample at 84 K. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Electrical and microstructural properties of low-resistance Ti/Re/Au ohmic contacts to n-type GaNPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 10 2007V. Rajagopal Reddy Abstract The microstructural and electrical properties of Ti/Re/Au (10 nm/10 nm/50 nm) ohmic contacts to moderately doped n-type GaN (4.0 × 1018 cm,3) have been investigated by current,voltage (I ,V), Auger electron microscopy (AES) and transmission electron microscopy (TEM). The electrical characteristics of as-deposited and annealing at temperatures below 800 °C samples exhibit non-linear behaviour. However, the sample showed ohmic behaviour when the contact is annealed at 900 °C for 1 min in nitrogen ambient. The Ti/Re/Au contacts give specific contact resistance as low as 8.6 × 10,6 , cm2 after annealing at 900 °C. It is shown that the surface of the as-deposited contact is fairly smooth and slightly degraded when the contact is annealed at 900 °C. The Ti/Re/Au ohmic contact showed good edge acuity after annealing at 900 °C for 1 min. Based on the Auger electron microscopy and transmission electron microscopy results, possible ohmic formation mechanisms for the Ti/Re/Au contacts to the n-type GaN are described and discussed. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||