Continued Heating Research Articles

Color formation during the fibrillization of whey protein isolate: Maillard reaction and protein oxidation

Although the connection between color formation and protein deterioration reactions such as oxidation and Maillard reaction is well known there is no information on such effects during the fibrillization of whey protein isolate fibrils (WPIF). This study identifies pH, temperature, and protein concentration that affect the deterioration reactions of WPIF during incubation and provides information on how these reactions affect the color formation of WPIF. Dye analysis and far-UV CD spectroscopy illustrated the formation of Cross-β. With continued heating, the unbranching semiflexible fibrils were formed, and the color of the samples deepened. With the rise of pH values, the final Maillard product content tended to be lower after 24 h. The Maillard reaction during fibrillization is temperature dependent (Ea = 133 kJ/mol). Increasing pH, temperature, or protein concentration could intensify protein oxidation during incubation. The carbonyls, N-formylkynurenine, and apparent Dityrosine oxidation increased continuously during 24 h. The principal component analysis and correlation analysis indicated that the color formation during the fibrillization of WPIF was caused by protein oxidation and the Maillard reaction. This study will give insights into protein fibrils prepared by commercial protein.

Extreme redox variations in a superdeep diamond from a subducted slab.

The introduction of volatile-rich subducting slabs to the mantle may locally generate large redox gradients, affecting phase stability, element partitioning and volatile speciation1. Here we investigate the redox conditions of the deep mantle recorded in inclusions in a diamond from Kankan, Guinea. Enstatite (former bridgmanite), ferropericlase and a uniquely Mg-rich olivine (Mg# 99.9) inclusion indicate formation in highly variable redox conditions near the 660 km seismic discontinuity. We propose a model involving dehydration, rehydration and dehydration in the underside of a warming slab at the transition zone-lower mantle boundary. Fluid liberated by dehydration in a crumpled slab, driven by heating from the lower mantle, ascends into the cooler interior of the slab, where the H2O is sequestered in new hydrous minerals. Consequent fractionation of the remaining fluid produces extremely reducing conditions, forming Mg-end-member ringwoodite. This fractionating fluid also precipitates the host diamond. With continued heating, ringwoodite in the slab surrounding the diamond forms bridgmanite and ferropericlase, which is trapped as the diamond grows in hydrous fluids produced by dehydration of the warming slab.

Failure modes and mechanisms of layered h-BN under local energy injection

Layered h-BN may serve as an important dielectric and thermal management material in the next-generation nanoelectronics, in which its interactions with electron beam play an important role in device performance and reliability. Previous studies report variations in the failure strength and mode. In this study, using molecular dynamics simulations, we study the effect of local heat injection due to the electron beam and h-BN interaction on the failure start time and failure mode. It is found that at the same heat injection rate, the failure start time decreases with the increase in the layer number. With the introduction of point defects in the heating zone, the failure always starts from the defect site, and the start time can be significantly shortened. For monolayer h-BN, failure always starts within the layer, and once failure starts, its propagation is through melting or vaporization of the h-BN atoms, and no swelling occurs. For multiple layers, once failure starts within the h-BN film, swelling occurs first. With continued heating, the large pressure induced by melting and vaporization can cause the burst of the layers above, leading to the formation of a pit. In the presence of multiple defects within the heating zone, these defects can interact, causing a further reduction in the failure start time. We also reveal the relation of beam power with layer-by-layer failure mode and swelling/pit formation mode. The present work not only reproduces many interesting experimental observations, but also reveal several interesting mechanisms responsible for the failure processes and modes. It is expected that the findings revealed here may provide useful references for the design and engineering of h-BN for device applications.

Incorporating vascular-stasis based blood perfusion to evaluate the thermal signatures of cell-death using modified Arrhenius equation with regeneration of living tissues during nanoparticle-assisted thermal therapy

Cellular and biological tissue heating may result in reversible (or repairable injury) and irreversible (or lethal) thermal cell-death in living biological tissues. Continuous regeneration of living human tissues due to the continuous supply of oxygen through arterial blood must be taken into account to counter balance the thermal degradation at quasi-static thermal conditions. This study incorporates vascular-stasis based non-linear blood perfusion for magnetic nanoparticle assisted thermal therapy to model the thermal by-stander effect - a hyperthermia-induced deep infiltration of nanoparticles in the targeted tissue domain. Pennes bioheat model based on Fourier heat conduction theory is four-way coupled with Arrhenius and non-Arrhenius kinetic models of cell-death with healthy cells regeneration. In determination of treatment endpoint, the kinetic model must be coupled with quantitative and qualitative pathological biomarkers of thermal damage. Nanoparticle distribution volume increases by 39.62% after possible rupturing of cell membrane during heating. The release of intracellular solution by dead cells during heating promotes nanoparticle migration from the region of higher concentration to the regions of lower concentration thereby 80% enhancement in interstitial space and five-fold increase in diffusion coefficient. For such redistribution phenomenon, the heating time is sufficient to reduce the oxygen in erythrocytes (red blood cells) and maximize the necrosis zone inside tumour. However, at the interface, the regeneration of healthy cells triggers an immune response of biological tissue towards continued heating to suppress, prevent and restrict further accumulation of thermal damage within damage bounds of Ω ≤ 1. While modelling the kinetics of thermal damage of tumour, one must include and should not ignore the partial self-regeneration of connecting normal human tissues at the tumour periphery due to continuous matching of oxygen demands in the healthy tissue by the arterial blood.

Determination and optimisation of Resonant Acoustic Mixing (RAM) efficiency in Polymer Bonded eXplosive (PBX) processing

An investigation into how the efficiency (time and energy required for homogeneity) of Resonant Acoustic Mixing (RAM) can be determined and optimised was undertaken. An idealised Polymer Bonded eXplosive (PBX) simulant based on glass microbeads (28.3 μm D50, 62% v/v in binder and plasticiser) was used for mixing. Mixing evolution was monitored using machine output data, whereby the mixer ‘intensity’ (related to power draw) was plotted against time. Experiments were undertaken with three acceleration settings, three mixer units, and three vessel materials of low, medium, and high surface free energy. Different stages of the mixer ‘intensity’ profiles were found to correspond to discrete stages of mixing, as well as further rheological changes due to continued frictional heating, thus viscosity reduction, beyond homogeneity being achieved. Time to mixing completion was found to be repeatable within a standard deviation of ±10%, strongly dependent on acceleration setting, and additionally dependent on vessel material, though additional data is required to confirm this. A significant difference in mixing time was observed between different LabRAM units. Partial vacuum application without degassing was beneficial for mixing. Finally, a paradigm linking the ‘movement modes’ of mixing was constructed, based on literature observations and the experimental results.

Barrovian and Buchan metamorphic series in the Chinese Altai: P–T–t–D evolution and tectonic implications

AbstractThe relations between Barrovian‐ and Buchan‐type metamorphic series in the Chinese Altai remain obscure, and hence a representative region of the central part of the Chinese Altai was investigated to address this issue, using combined microstructural, petrological and geochronological methods. In the region, Barrovian‐type garnet, staurolite, kyanite and sillimanite zones are locally overprinted by Buchan‐type andalusite‐ and cordierite‐bearing domains. Microstructural analysis shows that Barrovian garnet, staurolite and kyanite grew synchronously with the earliest regional metamorphic foliation S1B. A sillimanite‐bearing assemblage locally overprinted the assemblage of the staurolite zone in a foliation parallel with S1B, assigned as S1M. The originally subhorizontal S1B‐M foliation, metamorphic zones and mineral isograds were folded by F2 upright folds, leading to their inclination and juxtaposition to upper crustal levels. Subsequent D3 deformation affected heterogeneously all previous structures producing vertical high‐strain zones around low‐strain domains. The D3 high‐strain zones in the vicinity of Permian pegmatites are associated with Buchan‐type metamorphism and are characterized by syn‐D3 growth of andalusite and cordierite. Phase equilibria modelling of the staurolite/kyanite‐bearing assemblages suggests a prograde P–T path with an apparent thermal gradient of ~23°C/km associated with the S1B fabric. The partial re‐equilibration occurred in the sillimanite stability at ~670°C, corresponding to an apparent thermal gradient of ~34°C/km in the S1M fabric. Garnet to sillimanite metamorphic zones were subsequently exhumed without apparent re‐equilibration during the D2 event. The interpreted pressure–temperature (P–T) evolution of the Buchan‐type metamorphism on the basis of thermobarometry and phase equilibria modelling suggests significant heating processes, corresponding to apparent thermal gradient of 41°C/km or more. In situ U–Pb dating of monazite inclusions in staurolite revealed predominantly 280–260 Ma ages and minor older ages scattering between 350 and 290 Ma, interpreted as important monazite recrystallization during the D3 event. Monazite in andalusite and cordierite yielded only ages of 280–260 Ma, interpreted as dating the growth of these minerals. Lu–Hf garnet–whole rock isochron of a garnet–cordierite–chlorite schist gave an age of ca. 262 Ma, overlapping in time with the age of monazite in the cordierite. Combined with available regional data, the results suggest that the Barrovian‐type metamorphic cycle reflects a continued burial heating followed by decompression, probably connected with the Devonian suprasubduction tectonic switching between shortening and extension events. In contrast, the Permian Buchan‐type metamorphism documents an important heat input associated with regional NE–SW shortening, probably related to the Early Permian collision between the Chinese Altai and the southerly Junggar arc system.

The Role of Pre‐existing Crustal Weaknesses in the Uplift of the Eastern Tibetan Plateau: 2D Thermo‐Mechanical Modeling

AbstractThe crust of the eastern Tibetan Plateau is cut through by several ancient fracture zones, which existed prior to the Cenozoic uplift of eastern Tibet. However, the role of these pre‐existing crustal weak zones (CWZs) in the Cenozoic evolution of eastern Tibet is still poorly understood. Here, we conduct a series of 2D thermo‐mechanical simulations to investigate the role of CWZs in the uplift of eastern Tibet. Our results show that CWZs embedded in the continental lithosphere facilitate crustal thickening via folding and thrusting deformation and uplift of a rugged surface at the early stage of convergence. As crustal thickening continues, the lowermost crust begins to partially melt due to strain and radioactive heating. With continued thickening and heating, melt volume gradually increases, leading to the lower crust melt preferentially accumulating where the CWZs are situated. At a later stage, the partially molten layer becomes thick enough and starts to flow in a channel with respect to its upper and lower solid layers. CWZs behave as windows to steer the ascension of the partial melts, leading to melt doming through the CWZs. The melt doming contributes to a second local surface uplift. Parameter tests demonstrate that increasing the number of CWZs can accelerate such geodynamical processes, and that the CWZ orientation controls the polarity of lithospheric underthrusting. We suggest that the Cenozoic episodic uplift of the eastern Tibetan Plateau, revealed by thermochronological studies, was likely caused by a combination of pure shear crustal thickening and melt doming along the pre‐existing CWZs.

Kajian Tekno-Ekonomi Produksi Reaktor Pirolisis dalam Menghasilkan Bioarang dan Asap Cair

The techno-economy of pyrolysis products is very important because it is related to the profit and loss of production business. On the other hand, this product is very potential and good prospect, due to it can generate energy from wasted and problematic environmental waste. In addition, the equipment is very simple and very easy to make, maintain and operate, it does not require a large cost or capital. The research objective is to determine the economic value and BEP (Break Even Point) of pyrolysis combustion in producing liquid smoke and bio charcoal with biomass raw materials. Figure the characteristics of liquid smoke and bio-charcoal obtained such as heat value, pH, acid, specific gravity, viscosity, and color. The method used is initiated by testing the pyrolysis reactor, at this stage bio-charcoal products and liquid smoke are obtained, influenced by such as pyrolysis temperature, processing time and equipment. Followed by making bio charcoal briquette, this stage is mashed charcoal, making dough or packing, drying, then printing briquettes. And finally the process of re-liquidation of liquid smoke, by means of redestilation or continued heating so that it will produce liquid smoke grade 3, grade 2, and grade 1. The results obtained are known to have an economic cost of Rp. 244.720.000, and for equipment depreciation costs Rp. 144.839.000. For the cost of production per year, that is Rp. 100.925.000 and for the variable cost per kg, which is Rp. 4.888/kg. The initial capital required is Rp. 129.839.000. For the production cost of Rp. 7.476/kg. For the total price of sales is Rp. 100.939.306 and for BEP (Rp) which is Rp. 100.939.306 and BEP (kg) which is Rp. 13.495/kg. Keywords: BEP, economy, pyrolysis, bio charcoal, liquid smoke.

Why are cooktop fires so hazardous?

A series of experiments was conducted characterizing the flammability properties of small-scale corn oil fires. The oil was placed in a pan located on the center of an electric coil heating element associated with an electric cooktop. Ignition was accomplished with a torch with the heating element off or by auto-ignition when the heating element was on. The mass loss, heat release rate, pan bottom temperature, heat flux to the surroundings, and flame height were measured. The radiative fraction and combustion efficiency were estimated from the measurements. Heating the oil on a typical electric cooktop leads to auto-ignition of the oil. Continued heating of the oil on the cooktop enhances the vaporization of the oil and leads to rapidly growing fires with relatively large peak heat release rates. Under some conditions, heated corn oil can boil-over, a phenomenon in which the oil bulk density decreases until it flows over the pan sides. For a given pan volume, the occurrence of boil-over depends on the initial fuel volume. Compared to traditional gasoline pool fires, the corn oil undergoing auto-ignition and continued heating had larger peak values of heat release rate and peak flame height by factors of 3.1 and 1.6, respectively.

Heating and Eruption of a Solar Circular-ribbon Flare

Abstract We studied a circular-ribbon flare, SOL2014-12-17T04:51, with emphasis on its thermal evolution as determined by the differential emission measure (DEM) inversion analysis of the extreme ultraviolet (EUV) images of the Atmospheric Imaging Assembly instrument on board the Solar Dynamics Observatory. Both temperature and emission measure start to rise much earlier than the flare, along with an eruption and formation of a hot halo over the fan structure. In the main flare phase, another set of ribbons forms inside the circular ribbon, and expands as expected for ribbons at the footpoints of a postflare arcade. An additional heating event further extends the decay phase, which is also characteristic of some eruptive flares. The basic magnetic configuration appears to be a fan–spine topology, rooted in a minority-polarity patch surrounded by majority-polarity flux. We suggest that reconnection at the null point begins well before the impulsive phase, when the null is distorted into a breakout current sheet, and that both flare and breakout reconnection are necessary in order to explain the subsequent local thermal evolution and the eruptive activities in this confined magnetic structure. Using local DEMs, we found a postflare temperature increase inside the fan surface, indicating that the so-called EUV late phase is due to continued heating in the flare loops.

Graphene oxide nanoflakes from various agrowastes

AbstractNowadays, the synthesis of graphene/ graphene oxide from graphite precursor using oxidizing agents is the most common procedure, but the direct synthesis of graphene or graphene oxide from a non‐graphitic carbonaceous material without using inert atmosphere is really a great challenge. Besides, the chemistry behind the development of graphitic structure from a non‐graphitic material during the thermal heating is still not clearly understood. In this research work, three agrowaste materials viz. rice husk, sugarcane bagasse and newspaper were selected and subjected to pyrolysis in presence of trace amount of air. The continued heating at the optimum temperature has resulted in aromatization and condensation along with the oxidation within the cellulosic structure of the agrowaste, which finally resulted in the formation of graphene oxide nanoflakes directly. The mechanism of formation of graphene oxide from these agrowaste materials was studied, which suggested that any carbonaceous waste materials can be converted to graphene oxide by optimizing the thermal heating conditions.

Rheological Controls on Asperity Weakening During Earthquake Slip

AbstractEvolution of fault strength during the initial stages of seismic slip plays an important role in the onset of velocity‐induced weakening, which in turn, leads to larger earthquake events. A key dynamic weakening mechanism during the early stages of slip is flash heating, where stress concentrations at contacts on the interface lead to the rapid generation of heat. Although potential weakening from flash heating has been extensively modeled, there is little recorded microstructural evidence of its physical manifestations. We present results of a series of triaxial experiments on synthetic faults in quartz sandstone. Samples were subjected to a variety of normal stresses and ambient temperatures, to induce a range of slip event sizes and sliding velocities. We show the microstructural evolution of asperity interactions from the onset of flash heating through to the formation of grain‐scale areas of sheared melt. Using microstructural observations and mechanical data from the experiments, we model temperature and the viscoelastic behavior of the glass. Results suggest that, in the earliest stages of slip asperity contacts melt, but temperatures remain too low for viscous shear to occur within the melt layer. Instead melted asperities behave as glassy solids, facilitating continued frictional heating. With further slip, increased asperity temperatures allow the transition to viscous shear within the melt layer, facilitating weakening. These results highlight the dynamic evolution of the viscoelastic properties of the melt and resulting effects on asperity strength. Such complexity has, to‐date, not been fully addressed in modeling of flash heating.

Increasing the diagnostic signifcance of the laser Doppler flowmetry in assessing skin microcirculation in hypertension

Background.Hypertension (HTN) is associated with impaired skin microcirculation. Laser Doppler flowmetry is an objective, quantitative, instrumental method that allows evaluating skin microcirculation. However, the method was not widely used clinically due to high variability of perfusion and small difference between healthy people and HTN patients and, as a consequence, low diagnostic signifcance.Objective.To provide the grounds for the approaches increasing the informative value of skin microcirculation measurement by laser Doppler flowmetry in HTN patients.Design and methods.The study involved HTN patients (n = 13, the median age was 60 (49; 63) years) and young otherwise healthy volunteers without HTN (n = 12, the median age 26 (25; 27) years). Microcirculation measurement was performed by laser Doppler flowmetry using LAKK-02 device. Registration of microcirculation on the forearm skin was carried out during the occlusionheating test. The Mann-Whitney test was used to compare the parameters in two groups. The diagnostic accuracy of the method for the inverse classifcation of the subjects was evaluated using ROC analysis.Results.In HTN patients, the median baseline perfusion was 3,1 (1,84; 4,31) perfusion units (PU), in healthy volunteers — 4,29 (3,66; 8,14) PU (p = 0,04). The median area under the microcirculation curve for the frst 2 minutes of heating in HTN patients was 1206,7 (813; 1449) PU × s, in healthy volunteers — 1552,3 (1310; 1624) PU × s (p = 0,035). In healthy volunteers, the heating increased the perfusion by 596 % (386%; 878%), and in HTN patients perfusion increased only by 265% (180 %; 318%) (p = 0,01). The relative increase in perfusion during postocclusion hyperemia with continued heating compared with the baseline in healthy volunteers was 651% (493 %; 999%), and in HTN patients — 302 % (182 %; 436%) (p = 0,005). Thus, when comparing the average parameters for each period in the occlusion-heating test, only basic perfusion showed signifcant differences. However, when changed from absolute to relative parameters (the increase in microcirculation in relation to the vasodilating effects), the difference was signifcant. Moreover, sensitivity achieved was 75 % and specifcity — 84,6% (the inverse classifcation of groups).Conclusions.The physiological (the local heating of the forearm skin at a rate of 2 degrees Celsius per second, a combination of vasodilating effects) and mathematical (the transition from absolute to relative values) approaches provided an increase of the informative value of the laser Doppler flowmetry, as well as its sensitivity and specifcity.

Experimental study of the time period of continued heating rate on the pool boiling characteristics of saturated water

Pool boiling heat transfer and critical heat flux (CHF) in saturated water were experimentally studied under transient power conditions. A chrome-aluminum-iron alloy wire supported horizontally in a pool of water was used as the heating element. The heating rate in the test section was increased linearly depending on time by applying voltage control for 1 s to 5000 s. The heat flux was obtained by a second-order function of time. In this study, the increase in heat flux starts from the free convection regime to the film boiling regime. The transient boiling heat transfer coefficient (TBHTC), transient wire superheat temperature, transient heat flux and transient CHF were also obtained. The results showed that with increasing the time period, the TBHTC in the nucleate boiling increased, decreased in transition from the nucleate boiling to the film boiling, and again increased in the film boiling and the incipient boiling point decreased which may be due to a decreased number of nucleation sites and the explosive nature of the initial stage of nucleate boiling. The TBHTC decreased in the second part of the film boiling as both the heat flux and the vapor film thickness around the wire had increased. In addition, increasing the time period decreased the CHF and superheating temperatures in the CHF by up to a period of 100 s. After that, its trend approached the steady state boiling. The transient CHF reduction in the time period of 100 s is 40.5% relative to steady state condition which is the minimum transient CHF. The maximum increase in the transient CHF is in the time period of 1 s and equals to 46.7%. A high-speed camera was used to show bubble and vapor film behavior around the heating wire.

In situ imaging of the soldering reactions in nanoscale Cu/Sn/Cu and Sn/Cu/Sn diffusion couples

The soldering reactions of three-segmented Sn/Cu/Sn and Cu/Sn/Cu diffusion couples are monitored by in-situ transmission electron microscopy to reveal the metallurgical reaction mechanism and the associated phase transformation pathway. For Sn/Cu/Sn diffusion couples, there is no ε-Cu3Sn formation due to the relatively insufficient Cu as compared to Sn. Kirkendall voids form initially in the Cu segment and then disappear due to the volume expansion associated with the continued intermetallic compound (IMC) formation as the reaction progresses. The incoming Sn atoms react with Cu to form η-Cu6Sn5, and the continuous reaction then transforms the entire nanowire to η-Cu6Sn5 grains with remaining Sn. With continued heating slightly above the melting point of Sn, an Sn-rich liquid phase forms between η-Cu6Sn5 grains. By contrast, the reaction in the Cu/Sn/Cu diffusion couples results in the intermetallic phases of both Cu3Sn and Cu6Sn5 and the development of Cu6Sn5 bulges on Cu3Sn grains. Kirkendall voids form in the two Cu segments, which grow and eventually break the nanowire into multiple segments.

An assessment of barium and strontium carbonates as temperature and enthalpy standards

A study of the thermal behavior of both barium and strontium carbonates was performed in dynamic argon atmosphere over a wide range of temperatures. Both barium and strontium carbonates are white crystalline powders at room temperature. These compounds undergo reversible polymorphic transitions from the orthorhombic to hexagonal crystal forms when heated to temperatures above 800 °C. On further heating, the barium carbonate undergoes an additional polymorphic transition where the hexagonal form transforms to a face-centered cubic form near 976 °C. On continued heating, this cubic form of barium carbonate decomposes to barium oxide liberating carbon dioxide gas. Strontium carbonate, on the other hand, tends to be thermally less stable than barium carbonate. It is reported to lose mass over a broad range of temperatures beginning below the observed polymorphic transition (Charsley et al. in J Therm Anal Calorim 40:1415–1422, 1993). Our studies, using both differential thermal analysis (DTA) and thermogravimetric analysis techniques, attempt to answer questions of uncertainty of the reported temperatures of transition, as well as heats of transition, for these industrially important compounds. As a result of these findings, recommendations are given for the use of these compounds as reference standards for calibration of DTA instruments.

Acoustical and thermo physical properties of metal-ceramics composites in dependence on few volume concentration of metal

Metal-ceramics composites (cermets) are modern construction material used in different industry branches. Their strength and heat resistance depend on elastic and thermos physical properties. In this work cermets based on corundum and stainless steel (sintered in high vacuum at temperatures 1500 - 1600°C) are investigated. The volume steel concentration in the samples varies up 2 to 20 vol %. The elastic modules were measured by ultrasonic method at room temperature, measuring of thermo conductivity coefficient were carried out at temperatures 100, 200°C by method of continued heating in adiabatic calorimeter. We founded appearance of two extremes on dependences of elastic modules (E, G) on stainless steel concentrations, nature of which is unknown, modules values change in range: E = 110 - 310, G = 60 - 130GPa (for different temperatures of sintering). Similar dependence is observed for thermo conductivity coefficient which values varies up 10 to 40 W/(m.K). There is presented also discussion of results based on structure cermet model as multiphase micro heterogeneous media with isotropic physical properties in the work.

Frictional melting processes and the generation of shock veins in terrestrial impact structures: Evidence from the Steen River impact structure, Alberta, Canada

Shock-produced melt within crystalline basement rocks of the Steen River impact structure (SRIS) are observed as thin (1–510μm wide), interlocking networks of dark veins which cut across and displace host rock minerals. Solid-state phase transformations, such as ferro-pargasite to an almandine–andradite–majorite garnet and amorphization of quartz and feldspar, are observed in zones adjacent to comparatively wider (50–500μm) sections of the shock veins. Shock pressure estimates based on the coupled substitution of Na+, Ti4+ and Si4+ for divalent cations, Al3+ and Cr3+ in garnet (14–19GPa) and the pressure required for plagioclase (Ab62–83) amorphization at elevated temperature (14–20GPa) are not appreciably different from those recorded by deformation effects observed in non-veined regions of the bulk rock (14–20GPa). This spatial distribution is the result of an elevated temperature gradient experienced by host rock minerals in contact with larger volumes of impact-generated melt and large deviatoric stresses experienced by minerals along vein margins.Micrometer-size equant crystals of almandine–pyrope–majorite garnet define the shock vein matrix, consistent with rapid quench (100–200ms) at 7.5–10GPa. Crystallization of the vein occurred during a 0.1–0.15s shock pressure pulse. Majoritic garnet, formed during shock compression by solid state transformation of pargasite along shock vein margins, is observed in TEM bright field images as nanometer-size gouge particles produced at strain rates in the supersonic field (106–108). These crystals are embedded in vesiculated glass, and this texture is interpreted as continued movement and heating along slip planes during pressure release. The deformation of high-pressure minerals formed during shock compression may be the first evidence of oscillatory slip in natural shock veins, which accounts for the production of friction melt via shear when little or no appreciable displacement is observed. Our observations of the mineralogy, chemistry and microtextures of shock veins within crystalline rocks of the SRIS allow us to propose a model for shock vein formation by shear-induced friction melting during shock compression.

Possibilities of acoustic thermometry for controlling targeted drug delivery

Model acoustic thermometry experiments were conducted during heating of an aqueous liposome suspension. Heating was done to achieve the liposome phase transition temperature. At the moment of the phase transition, the thermal acoustic signal achieved a maximum and decreased, despite continued heating. During subsequent cooling of the suspension, when lipids again passed through the phase transition point, the thermal acoustic signal again increased, despite a reduction in temperature. This effect is related to an increase in ultrasound absorption by the liposome suspension at the moment of the lipid phase transition. The result shows that acoustic thermography can be used to control targeted delivery of drugs mixed in thermally sensitive liposomes, the integrity of which is violated during heating to the phase transition temperature.

On buoyancy driven mixing by volumetric microwave energy deposition

Investigation of buoyancy driven mixing by volumetric energy deposition is of particular interest to inertial confinement fusion research. This contribution describes a new microwave facility and an experiment to study buoyancy driven mixing of miscible fluids by volumetric energy deposition. A light weakly-polar fluid initially rested on top of a heavier and higher polarity fluid. As the fluid system was subjected to microwave radiation, less microwave energy was deposited into the weakly-polar fluid than the higher polarity fluid; thus, the bottom fluid was preferentially heated, and its density decreased due to thermal expansion. With continued microwave heating, the density of the bottom fluid dropped below the density of the upper fluid, creating a Rayleigh–Taylor unstable configuration, and, subsequently, buoyancy driven mixing. The miscible pair of toluene and tetrahydrofuran was chosen for the volumetric energy deposition experiments presented. Initially, single fluid microwave heating experiments, for which the source term in the heat equation was varied by variations in the fluid volume, were performed to provide calibration of a mathematical model. The model provided a prediction of the neutral stability point of the system, which facilitated experimental design and understanding. Measurements of the mixing layer width from this two-fluid mixing experiment are compared with results from a self-similar analysis of the governing equations.