Reduction In Specific Volume Research Articles

The effects of flour and protein preparations from amaranth and quinoa seeds on the rheological properties of wheat-flour dough and bread crumb

The effects of amaranth and quinoa flours and protein isolates prepared from amaranth and quinoa seeds on the rheological properties of wheat flour dough and bread were studied using new recording instruments, the micro Z-arm mixer (for dough) and the SMS-Texture analyser (for bread crumb). The addition of 10% amaranth or quinoa flours did not cause significant changes in rheological properties. However, higher additions (20% and 30%) resulted in significant changes in stability, the degree of softening and elasticity. Substitution of wheat flour by amaranth or quinoa flours resulted in an increase of water absorption capacity. A significant reduction of specific volume and an increase of resistance to deformation (firmness) of the crumb of breads prepared from flour mixtures containing high percentages of amaranth or quinoa flours was observed. The addition of protein isolates did not significantly influence the main rheological parameters of dough, and bread crumb.

Morphological changes of mucous membrane of maxillary sinus at odontogenic perforative sinusitis

Methods of light, electronic microscopy and immunohystochemistry lead research of structural changes of a mucous membrane maxillary sinus at 43 patients with odontogenic perforative sinusitis. The material is broken into 4 groups depending on a limitation period of punching. Degenerate changes ciliated epithelial cells came to light already on early terms after perforations of sinusitis and were shown by reduction of specific volume of mitochondrias, the GER, increase NCR. In globlet exocrine cells reduction NCR is connected to infringement of evacuation of a secret. In terms more than 3 months occured metaplasia of epithelium in single-row cubic and multilayered flat with keratosis, increased cellular infiltration own plate of a mucous membrane maxillary sinus. The contents of CD4 + cells in a mucous membrane of sine gradually increased, and on late terms of occurrence of perforations decreased. The contents of CD8+ and СD20+ cells in a mucous membrane with perforations of sinusitis were raised.

Behavioral and anatomical abnormalities in Mecp2 mutant mice: A model for Rett syndrome

Over 90% of Rett syndrome (RTT) cases have a mutation in the X-linked gene encoding methyl CpG binding-protein 2 (MeCP2). A mouse model that reprises clinical manifestations of the disease would be valuable for examining disease mechanisms. Here, we characterize physical and behavioral measures, as well as brain region volumes in young adult mice that have mutations in mouse methyl CpG binding-protein 2 gene ( Mecp2) to serve as a baseline for other studies. Hemizygous males, which produce no functional protein, exhibit hypoactivity and abnormalities in locomotion, stereotypies, and anxiety reminiscent of the clinical condition. The mutant males also exhibit cognitive deficits in fear conditioning and object recognition relative to wildtypes. Volumetric analyses of male brains revealed a 25% reduction in whole brain volume in mutants relative to wildtypes; regional differences were also apparent. Mutants had decreased volumes in three specific brain regions: the amygdala (39%), hippocampus (21%), and striatum (29%). Heterozygous females, which produce varying amounts of functional protein, displayed a less severe behavioral phenotype. The mutant females exhibit abnormalities in locomotion, anxiety measures, and cognitive deficits in object recognition in an open field. This study provides the first evidence that the abnormal motor and cognitive behavioral phenotype in Mecp2 mice is consistent with specific volume reductions in brain regions associated with these behaviors, and shows how these data parallel the human condition. The Mecp2 mutant mice provide a very good model in which to examine molecular and behavioral mechanisms, as well as potential therapeutic interventions in RTT.

Structural aspects of annealing and hot deformation of Al-Nb2O5 mechanically alloyed composite

A mechanical alloying and hot extrusion method was used to manufacture an Al based composite reinforced by 10 wt-% addition of Nb2O5. Annealing experiments were performed to test the effect of chemical reaction between components on the material structure. After annealing at 873 K for 12 h the material hardness was found to have increased from HB 121 (as extruded) to HB 186 (annealed). The hardness maximum was followed by material softening at prolonged aging at 873 K. Transmission electron microscopy observations revealed a very well consolidated nanoscale structure for the as extruded composite. Annealing of the material resulted in an increase in porosity that was ascribed to Nb oxide reduction by aluminium. Due to diffusion of the released Nb element into the surrounding Al matrix, formation of new intermetallic grains of Al3Nb was accompanied by very fine needlelike Al oxide particle growth within the aluminium matrix. Chemical reaction between aluminium and Nb oxide at solid state was related to local specific volume reduction being responsible for an increase in the material porosity. Hot compression tests were performed on as extruded and samples annealed at 873 K for 12 h. The good mechanical properties of the composite were ascribed to the highly refined structure of the material. In compression tests, samples were not fractured within the experimental strain range used. In hot deformation tests at lower temperatures and a strain rate of 5 10−3 s−1, some fine microcavities were observed by TEM for samples deformed to ɛt≈0·3.

Structure evolution in annealed and hot deformed Al–V2 O5 composite

Structural observations and hot deformation tests were carried out on mechanically alloyed Al-10 wt-%V2 O5 composite. Initial annealing experiments revealed a hardening of the material during the first stage of annealing. The material hardness increased from 114 HB for as extruded material to 167 HB after annealing at 873 K for 6 h. Differential scanning calorimetry tests conducted on as extruded material confirmed the development of an exothermic reaction during heating of the material within the temperature range 650–870 K. The amount of heat released was reduced with increasing annealing time at 873 K. Transmission electron microscopy (TEM) and X-ray analysis of annealed material revealed new intermetallic grains and very fine aluminium oxide particles, which resulted from the chemical reaction between the aluminium matrix and vanadium oxides. The development of voids in long aged specimens was found to be an undesirable effect of local specific volume reduction during the course of the chemical reaction that was not fully compensated by the local volume increase due to the growth of intermetallic particles. As a result, the material hardness was reduced in long time annealed specimens. The mechanical properties of as extruded and annealed specimens were investigated by means of hot compression testing within the temperature range 623–903 K. These tests revealed that the flow stress of as extruded material was reduced from 180 to 22 MPa when tested at 623 and 903 K, respectively. Annealed specimens exhibited higher flow stresses of 195 and 32 MPa at the same temperatures. The results indicate that the strength of the material can be effectively increased owing to a change of material structure as a result of the chemical reaction taking place during high temperature annealing.

Pressure−Volume−Temperature Dependence of Polypropylene/Organoclay Nanocomposites

The pressure−volume−temperature (PVT) dependencies of commercial polypropylene melt (PP) and its nanocomposites containing X wt % of organoclay (Cloisite-15A, or C15) and 2X wt % of a compatibilizer were determined at T = 450−530 K and P = 0.1−190 MPa. C15 was used at concentrations: X = 0, 2, and 4 wt %. Three functionalized PP's were used as compatibilizers: two maleated and one grafted with glycidyl methacrylate. Incorporation of X = 2 wt % C15 into PP resulted in reduction of specific volume by ΔV ≈ 1%, but that of free volume (hole) fraction by Δh ≈ 5%. The latter quantity was computed from the Simha−Somcynsky lattice−hole equation of state. Furthermore, at constant T and P the hole fraction was found to be linearly related to the bulk-average energetic interaction parameter and to be a sensitive indicator of structural changes. In binary (polymer + organoclay) systems Δh is linearly related to the interlayer spacing, d001. So, where statements from the previous paper are repeated or there are similarities, this is done for purposes of comparison. In three-component systems (with a compatibilizer) the proportionality has been preserved, but large changes of Δh result in relatively small changes of d001. Mechanical properties hardly correlate with either Δh or d001, as polymer/compatibilizer morphology and crystallinity complicate the behavior.

The mechanics of cemented carbonate sands

The behaviour of artificially cemented carbonate sand was investigated in triaxial tests at confining pressures of up to 9 MPa. The results show that an important effect of cementing is a reduction in specific volume resulting from the increase in fines content This influences both the stress-strain behaviour and the peak strength at strains beyond those required to fracture the cement bonding. Comparisons between the behaviour of cemented and uncemented soils should, therefore, be carried out on samples with the same gradings. For cemented samples it is possible to identify a yield curve outside the state boundary surface of the uncemented soil. A framework for the behaviour has been defined which depends on the relative magnitudes of the confining pressure and cement bond strength. The behaviour of a natural cal-carenite agreed well with this framework which is also likely to be applicable to other cemented soils. Le comportement d'un sable carbonate artificiellement cimenté a été étudié à l'aide d'essais tri-axiaux à pression de confinement pouvant atteindre 9 MPa. Les résultats obtenus montrent que la cimentation se traduit par une diminution du volume spécifique due à une augmentation du nombre de particules fines. Ceci modifie le comportement contrainte-déformation ainsi que la résistance ultime pour des déformations supérieures à celles provoquant la rupture des liaisons du ciment. L'étude comparative du comportement de sols cimentés et de sols non-cimentés a donc dû être réalisée sur des échantillons de mâme granulo-métrie. Pour des échantillons cimentés, une courbe de rupture située en dehors de l'enveloppe limite d'un sol non-cimenté a été mise en évidence. Une classification de comportement a été élaborée en fonction des amplitudes relatives de la pression de confinement et de la résistance des liaisons du ciment. Le comportement d'une calcarénite naturelle est tout à fait en accord avec cette classification qui apparaît applicable à d'autres sols cimentés.

Dilatometric errors and an application to volume changes for the solid state of methyl stearate

SummaryThe dilatometric curves representing heating and cooling cycles for methyl stearate between‐38°C. and +35°C. are the same shape as found in the previous study. Cooling cycles which are started from points on the heating curve yield curves which are different from each other and from curves representing the complete heating and cooling cycles. Curves for heating cycles which are started from points on the curve representing the complete cooling cycle will also be different from the curves representing either the heating or cooling cycles in the same temperature region. The specific volumes at any temperature in the solid region depend on the previous history of the sample even though the sample is not melted between determinations. A continual reduction in specific volume was found for successive runs after equilibration at+35°C. This reduction had no apparent effect on the coefficient of expansion of the solid state but did increase the melting dilation. Using the present Vycor dilatometers, the standard error of measurements in the solid state are around ±0.00005 ml. per gram in terms of specific volume. The use of a platinum resistance thermometer and Mueller bridge did not significantly improve the precision of the measurements.

The interaction of clay with water and organic liquids as measured by specific volume changes and its relation to the phenomena of crumb formation in soils

The densities of clay particles determined by the specific gravity bottle method vary somewhat according to the liquid used. Thus water, alcohol, and benzene all give slightly different values. The results show that some condensation of the liquid on the surface of the particles usually, if not invariably, takes place, indicating a certain amount of interaction between the clay and the liquid. The investigation described in this paper shows that this interaction depends partly on the exchangeable bases associated with the clay, and partly on the molecular constitution of the liquid. The relations are as follows : (1) No evidence could be obtained of interaction between clay and non-polar liquids. (2) Interaction took place in all the polar liquids examined. Its amount was measured by the reduction in specific volume of the clay as compared with its volume in tetralin, a very convenient non-polar liquid for specific gravity determinations. This reduction in specific volume is approximately proportional to the number of exchangeable cations present, figs. 10, 11, and to the mean density of their surface charge, Table IV.