Thermal Properties

A series of highly cross-linked polysiloxane was synthesised via hydrosilylation and condensation reaction. Structural identification using Fourier Transform Infrared (FTIR) and 1 H-NMR confirmed their chemical structures. Their thermal and, mechanical properties, and crystallinity, were analysed and related to the level of cross-link density. These systems displayed elevated thermal and hardness properties at an increased cross-link density. Furthermore, the level of crystallinity was reduced as displayed by XRD analysis. Along with this observation, the calculated fractional free volume (FFV) showed a decreasing trend leading to the 'densification' effect. It was envisaged that the linear polysiloxane chain segments aligned parallel to each other in a triclinic crystal system to generate a crystalline domain. The spacing between these stacking chains was found to be about 7.2 Å as measured from simulated XRD pattern.

Protein concentrates prepared by expanded bed adsorption (EBA) chromatography from industrial potato juice (PJ) were analysed for chemical composition, color, enzyme activities, thermal properties and selected functional properties (solubility and emulsifying stability). Two EBA multi-modal resins, MIMO I-45 and MIMO 1300 (UpFront Chromatography), were employed under various pH conditions resulting in four potato protein concentrates, AD. Concentrate B contained an electrophoretically pure protease inhibitor fraction (20-21 kDa), whereas concentrate A, C and D contained both patatin (41 kDa) and protease inhibitors. The potato protein concentrates were explored for the presence of transitions from native to denatured states using differential scanning calorimetry (DSC). Concentrate C had lower heat of transition (DH) and T-onset than the other concentrates. The concentrate containing protease inhibitors exhibited the highest denaturation temperature and enthalpy. All concentrates differed significantly (P < 0.05) in color brightness, with concentrate B and D emerging as the brightest. The solubility of the concentrates was evaluated at pH 6 and pH 4.5. All concentrates had lower solubility at pH 4.5 than at pH 6 (70-80%). The stability of emulsions (1% protein, 20% oil, 0.08% xanthan gum) against creaming was analysed with a new method based on the Single electrode Capacitance Probe (SeCaP) technology. Small differences among concentrates were observed by the new SeCaP method.

N O R M A S E M É T O D O S Introdução Durante o processo de extrusão o polímero experimenta uma complicada história térmica . No trajeto inicial da extrusora, as partículas sólidas do polímero são aquecidas até o ponto de fusão. Na região intermediária, a temperatura do polímero fundido é aumentada até um nível considerável acima do ponto de fusão, enquanto as partículas sólidas remanescentes continuam sendo aquecidas até a sua fusão. Na região final da extrusora, o polímero fundido tem que alcançar um estado termicamente homogêneo. Quando o material deixa a extrusora ele é, então, resfriado normalmente até a temperatura ambiente. Pode-se concluir, portanto, que o conhecimento das propriedades térmicas de polímeros é crucial na descrição e análise do processo de extrusão.

Rheological and thermal properties of agar sol and gel in presence of various cationic, anionic and non-ionic surfactants are reported. The agar used was from the red seaweed Gelidiella acerosa. The gel strength, viscosity, rigidity (G ), gelling temperature and melting temperature were observed to decrease in presence of non-ionic surfactants whereas these were enhanced in presence of ionic surfactants. TGA studies showed that 1.5% agar gels containing non-ionic surfactants lose water at a lower temperature than the control agar gel whereas gels containing ionic surfactants hold on to water more tenaciously. DSC studies, on the other hand, show that the gel to sol transition occurs at lower temperatures in presence of non-ionic surfactants and at higher temperature in presence of ionic surfactants when compared with the control gel. The non-ionic surfactants, Triton X-100 and Brij 35, enabled relatively concentrated agar extractive to be filtered readily, as a result of which water usage in the process could be reduced by 50%. The surfactant was subsequently removed through freeze-thaw operations to restore the gelling capacity of the agar. The finding that 0.3-0.4% (w/v) sodium lauryl sulfate (SLS) lowers the sol-gel transition temperature from 41 to 36 • C without adversely affecting gel strength is another useful outcome of the study that may enable better formulations of bacteriological agar to be prepared.

Bisthiourea Zinc Acetate (BTZA) a semi organic material has been synthesized by slow evaporation method using water as a solvent. The solubility studies have been carried out in aqueous solution in the temperature range 25 ˚C – 45 ˚C. Crystals have been grown from low temperature solution method by slow evaporation of saturated aqueous solution at room temperature. Single Crystal X-ray diffraction study has been carried out to determine the lattice parameter of the grown crystal. The spectral bands have been compared with similar thiourea complexes using FTIR spectrum in the range 400 – 4000 cm-1. Optical transmittance and absorption percentage of the grown crystal have been measured from UV-Vis studies. The thermal behavior has been investigated by thermogravimetric (TGA) and Differential Thermogram analyses (DTA). The mechanical strength and work hardening coefficient of the grown crystal have been analyzed by Vicker’s microhardness method. Keywords: Growth from solutions; X-ray d...

The properties of 20 wt % CeO 2 and 21 wt % Ce 0.5 Zr 0.5 O 2 films, deposited onto a γ-Al 2 O 3 by Atomic Layer Deposition (ALD), were compared to bulk Ce 0.5 Zr 0.5 O 2 and γ-Al 2 O 3-supported samples on which 20 wt % CeO 2 or 21 wt % CeO 2-ZrO 2 were deposited by impregnation. Following calcination to 1073 K, the ALD-prepared catalysts showed much lower XRD peak intensities, implying that these samples existed as thin films, rather than larger crystallites. Following the addition of 1 wt % Pd to each of the supports, the ALD-prepared samples exhibited much higher rates for CO oxidation due to better interfacial contact between the Pd and ceria-containing phases. The redox properties of the ALD samples and bulk Ce 0.5 Zr 0.5 O 2 were measured by determining the oxidation state of the ceria as a function of the H 2 :H 2 O ratio using flow titration and coulometric titration. The 20 wt % CeO 2 ALD film exhibited similar thermodynamics to that measured previously for a sample prepared by impregnation. However, the sample with 21 wt % Ce 0.5 Zr 0.5 O 2 on γ-Al 2 O 3 reduced at a much higher P O 2 and showed evidence for transition between the Ce 0.5 Zr 0.5 O 2 and Ce 0.5 Zr 0.5 O 1.75 phases.

In this work, ␤-SnS 2 thin films have been prepared on glass substrates by the spray pyrolysis technique using an alcohol solution which contains tin chloride (SnCl 4) and thiourea (SC(NH 2) 2) as precursors. The structural study shows that ␤-SnS 2 thin film prepared using optimal experimental conditions: substrate temperature T s = 280 • C and the concentration ratio of sulfur and tin elements in the spray solution x = [S]/[Sn] = 2.5, crystallizes in the hexagonal phase with a strong (0 0 1) X-ray diffraction line. In the same way, microprobe analyses (EPMA) as well as X-ray photoelectron spectroscopy (XPS) show the presence of undiserable phase of SnO 2. From the transmission and reflectance spectra, the band gap energy is 2.65 eV. On the other hand, the photothermal properties of such films have been studied, the thermal conductivity was K c = 0.85 W m −1 K −1 and the thermal diffusivity was D c = 14.5 × 10 −6 m 2 s −1. The analysis of ␤-SnS 2 thin films via the photodeflection spectroscopy including the effect of the inhomogeneity at the surface (roughness) and in the bulk (air inclusion, secondary phase of SnO 2) have been discussed for future investigations.

Glasses were prepared by the melt-quenching method in the ternary system Pb(PO 3 ) 2 -WO 3 -PbF 2 and doped with Er 3+ in order to prepare luminescent transparent glass-ceramics. This work focused on thermal and structural characterization of tungsten lead-phosphate glasses and crystallization study for preparing transparent glass-ceramics. Thermal properties such as thermal stability and crystallization behavior upon heating were investigated by DSC in function of PbF 2 content. For low PbF 2 concentrations, only one crystallization peak due to Pb 3 (PO 4 ) 2 is observed whereas samples containing more than 15% of PbF 2 present another exothermic event at lower temperatures related with precipitation of PbF 2 , Pb 2 P 2 O 7 and Pb 2 OF 2 . Structural investigations by Raman spectroscopy suggest that PbF 2 modifies the tungsten-phosphate network through the formation of P-F and P-O-Pb bonds but the average network connectivity remains almost constant. A crystallization study has been performed by DSC to investigate the dominant crystallization mechanisms in these glasses and it has been established that Pb 3 (PO 4 ) 2 is nucleated on the surface whereas PbF 2 , Pb 2 P 2 O 7 and Pb 2 OF 2 crystallize dominantly from the glassy bulk. Transparent glass-ceramics containing nanosized PbF 2 crystallites were also prepared by suitable heat-treatment on the glass sample containing 20% of PbF 2 and Raman microscopy of these glass-ceramics supports the crystallization mechanisms determined by DSC.

Determination of the lattice dynamics of Sn at high pressure has represented a major experimental challenge and eluded previous attempts. Here we report the first successful measurement of the phonon density of states of Sn at high pressure to 64 GPa using nuclear resonant inelastic x-ray scattering. We also present density functional theory calculations that are in excellent agreement with the measured data. The results of this combined experimental and theoretical study establish reliable phonon density of states of Sn at high pressure. It makes possible an accurate description of its thermodynamic properties that are of great importance and interest in high pressure research.

Stability of drugs and products has a great practical interest, which is facing to strict regulation. Thermal studies, besides the determination of the thermal properties of the investigated product allow the verification of possible interactions between the drug substances and excipients. The objective of this work was to obtain solid pre-formulates of paracetamol (PC) by spray drying (SPDR), as well as to investigate their thermal behavior. Dynamic and isotherm TG, conventional DSC and DSC-photovisual coupled methods were used to characterize the conventional and pre-formulated mixtures obtained by SPDR. The results of both DSC investigations showed slight alterations in melting temperatures, which suggests incompatibilities. The TG decomposition data of the mixtures evidenced that the dry process via SPDR leads to stability enhancement of the pre-formulated mixtures.

Typical montmorillonite clays (Cloisite Ò Na + , Cloisite Ò 30B) were modified by treatment with octadecyl ammonium chloride (ODC) and successive additions of octadecylamine (ODA). XRD analyses of the modified clays indicated an increase of the basal spacing of the (0 0 1) planes depending on the ODC or ODA additions.

We apply a range of techniques (thermal methods, microscopy, X-ray diffraction, IR spectroscopy) to characterize a drug (atenolol), several excipients (PVP=polyvinylpyrrolidone, MGST=magnesium stearate, Avicel © ) and drug-excipients mixtures either as prepared, annealed, and exposed to moisture. We compare the data of the mixtures with those computed from a weighted average of similarly treated pure compounds to find evidence of drug properties modified by the interaction with the excipient. We find that thermal response is by far the most sensitive indicator of interaction while IR is the least sensitive one.

Ca 3 Co 4 O 9 thermoelectric (TE) ceramics have been processed using conventional sintering (CS), hotpressing (HP) and spark plasma sintering (SPS). Microstructure investigations have revealed that HP processing is effective for obtaining highly textured 349 ceramics, with a degree of crystallite orientation showing a texture index of 6 mrd 2 , and that SPS affords strong densified 349 ceramics, typically 98% of the theoretical X-ray density. Investigations of mechanical and thermal properties were undertaken for a reliable integration of these materials in practical devices. In detail, these properties were assessed by microindentation, nanoindentation and three point bending tests. Hardness, elastic modulus, strength and fracture toughness of the HP and SPS samples were drastically improved, compared with the CS specimen. The thermal expansions were measured and shown, for the samples processed by HP and SPS, different between the directions parallel and perpendicular to the stress axis. Thermoelectric properties were investigated from 5 to 850 K and a remarkable power factor value of 550 W m −1 K −2 was obtained at 850 K. Mechanical and TE properties were correlated to the microstructure and texture features.

An experimental study was carried out in order to determine the properties of local materials used as construction materials. Cement stabilized compressed bricks were tested. The thermal properties of lateritic soil based materials were determined. The objectives of work reported in this paper are to determine the effect of addition of pozzolan or sawdust in lateritic soil brick on the thermal properties. It was shown that the effect of incorporation of pozzolan or sawdust is the decreasing of the thermal conductivity and density. The moisture content of these materials can modify their thermal performance. Thus a study of the influence of the water content on the thermal conductivity k and the thermal diffusivity a is presented. The thermal conductivity as a function of water content increases rapidly between 0 and 12% for lateritic soil. The thermal diffusivity curve presents a maximum for values of water content of 15% for lateritic soil and 8% for lateritic soil-pozzolan or lateritic soil-sawdust. However, the composite materials used for building shielding must present sufficient mechanical strength to be suitable for constructions. According to the experimental results the effect of adding cement or pozzolanic stabiliser is expressed in increase of strength of samples studied. ᮊ

The cooling of silicate melts influences the character of volcanic processes, primarily through the effect of temperature on melt viscosity but also through the derivative thermal properties, expansivity and heat capacity. If the cooling rates of volcanic facies can be established then the undoubtedly complex processes of erupting, cooling and degassing magmas can be more readily understood. The frozen structure of every glass, volcanic or synthetic, is influenced by the previous cooling history. Moreover, the relaxation of the glass structure back to equilibrium during reheating across the glass transition is also dependent on the quenched-in structure and thus can be used to determine the cooling rate history.

Increasing the unsaturated fatty acid (UFA) content in milk fat is of primary importance to improve the longterm health of consumers. However, such changes can affect the crystallization properties of milk triacylglycerols (TAG) and their functional properties. The objectives of this study were to investigate the crystallization properties of milk fat as a function of its FA composition and emulsion droplet size upon storage at refrigerated temperature. UFA-enriched TAG were obtained using cow diet supplemented with linseed oil and compared to control TAG. Homogenization was used to vary the size of emulsion droplets, from 1.7 to 0.2 μm. The crystallization properties of TAG were studied using synchrotron X-ray diffraction coupled to differential scanning calorimetry. We characterized the coexistence of several solid fat phases with a liquid phase, the characteristics of which depended on the temperature, FA composition and droplet size. The enrichment in UFA from 29 to 51 wt.% led to a decrease in the enthalpy ratio (ΔH partial /ΔH total ) from 64 ± 4 to 54 ± 4% at 4°C and to the formation of 2 L (41.8 Å) structure with β 1 , β′ 1 , and β′ 2 polymorphic forms while 2 L (39.5 Å) and 3 L (56.6 Å) structures with β 1 , β 2 , β′ 1 and β′ 2 polymorphic forms were formed with control TAG. The size of the emulsion droplets also affected the structural and thermal properties of milk TAG. Such experiments increased the knowledge about the crystallization properties of TAG dispersed in emulsion and will be useful for industrial applications and the development of UFA-enriched dairy products with improved nutritional properties.

The quantum deformation of the Hopf algebra describes the skeleton of quantum field theory, namely its characterizing feature consisting in the existence of infinitely many unitarily inequivalent representations of the canonical commutation relations. From this we derive the thermal properties of quantum field theory, with the entropy playing the role of the generator of the non-unitary time evolution. The entanglement of the quantum vacuum appears to be robust against interaction with the environment: on cannot "unknot the knots" in the infinite volume limit.

A series of thermal conductivity measurements for various materials was performed in a large climate chamber. The size of the chamber allowed the preparation of relatively large samples in a controlled thermal environment. Three types of thermal sensors were used: (1) two needle probes; (2) a grid of temperature sensors, evenly distributed inside the sample; (3) two additional thermal probes, which were simplified versions of an instrument originally developed for measuring thermal properties of the ice/dust mixture expected to exist at the surface of a comet nucleus. They consist of a series of individual temperature sensors integrated into a glass fibre rod. Each of these sensors can be operated in an active (heated) or passive (only temperature sensing) mode. The following sample materials were used: fine-grained reddish sand, coarse-grained moist sand, gravels with various grain size distributions from < 1 cm up to about 6 cm, and for comparison and calibration pure water (with convection suppressed by adding agar-agar), compact ice, and compact granite. Of particular interest are the measurements with composite samples, like stones embedded in an agar-agar matrix. We describe the evaluation methods and present the results of the thermal conductivity measurements.

A new nonlinear optical material tetrakis thiourea nickel chloride (TTNC) was synthesized and single crystals were grown from mixed solvent of water and isopropanol by both slow evaporation and slow cooling methods. The grown crystals were characterized by powder X-ray diffraction analyses to confirm the crystal structure. The presence of functional groups and the coordination of metal ions to thiourea were confirmed by FTIR and Raman spectroscopy analyses. UV-VIS spectrum was recorded to study the optical transparency of the grown crystals. Thermal properties of the crystals have been by investigated using thermo gravimetric (TG) and differential thermal analyses (DTA), which indicate that the material does not decompose before melting. The second order nonlinear optical property of the grown crystal was examined by Kurtz powder technique and mechanical behavior was studied by Vicker's microhardness test.

We present estimates of the basic physical properties (size and albedo) of (90377) Sedna, a prominent member of the detached trans-Neptunian object population and the recently discovered scattered disk object 2010 EK 139 , based on the recent observations acquired with the Herschel Space Observatory, within the "TNOs are Cool!" key programme. Our modeling of the thermal measurements shows that both objects have larger albedos and smaller sizes than the previous expectations, thus their surfaces might be covered by ices in a significantly larger fraction. The derived diameter of Sedna and 2010 EK 139 are 995 ± 80 km and 470 +35 −10 km, while the respective geometric albedos are p V = 0.32 ± 0.06 and 0.25 +0.02 −0.05. These estimates are based on thermophysical model techniques.

Thermal effects produced in a Hoya LSG-91H Nd:glass laser rod pumped uncooled in a close-coupled double circular chamber, at high input powers, were evaluated in the single shot and repetitively pulsed modes by passing a He-Ne laser probe beam through the rod and observing the changes in the beam intensity. When pumped with a 200 ps, 100 J flashlamp pulse, it was observed that the thermal effects lasted for about 2-2.5 s at the center of the rod and 0.2-0.5 s at the rod edges. The minimum induced focal length of the laser rod was-57.3 cm in the single shot mode and-54.9 cm in the repetitively pulsed mode. In the repetitively pulsed mode, in addition to the lens effect, a prism effect was also observed, which increased in strength with increase in input energy. These lens and prism effects were found to be dependent on the energy deposition profile in the laser rod and on its thermal properties. K. Sathianandan was born in Kerala, India, on December 31, 1926. He received the B.Sc. degree (Hons.

The demand to print increasingly smaller microelectronic device features means that the thickness of the polymer films used in the lithographic processes must decrease. The thickness of these films is rapidly approaching the unperturbed dimensions of the polymer, length scales at which confinement deviations and dewetting are a significant concern. We combine specular x-ray reflectivity ͑SXR͒ and incoherent neutron scattering ͑INS͒ to probe the thermal stability and dynamical effects of thin film confinement in poly͑hydroxy styrene͒ ͑PHS͒, a polymer used in a majority of the 248 nm deep UV photoresists. PHS forms stable thin films ͑down to 5 nm͒ that do not dewet over a wide temperature range on Si surfaces ranging from hydrophilic to hydrophobic. The surface energy has a profound influence on the magnitude of the thin film expansion coefficient, especially above the glass transition, in films as thick as 100 nm. Confinement also appears to suppress the mean-square atomic displacements and the level of anharmonicity in the dynamics, primarily above the bulk glass transition.

Ultrasonic spectroscopy is a promising measurement technique for the characterisation of emulsions and suspensions over a wide range of particle size and concentration. It appears highly suitable for on-line applications, in particular for dense nano-sized particle systems, where the system stability may be very sensitive to changes in the concentration. In the case of colloidal dispersions the particle sizes are usually smaller than the sound wavelength. Then dissipative processes rather than scattering govern the acoustic behaviour of such systems. The dissipative processes, however, are affected by several material properties, whose significance for the overall acoustic behaviour depends on the type of the material system, e.g. thermal properties are important in the case of emulsions and non-watery suspensions but not for watery suspensions. Often the information on these parameters is incomplete and not sufficiently accurate. In this paper the stability of ultrasonic particle size measurement against incorrect values of the relevant material properties is investigated. This was done firstly by analytical consideration. From this, the degree of influence of the respective material properties on the analysis of spectrometric measurements was derived for oil-water-emulsions, watery and non-watery suspensions. It could be shown that the single properties affect the analysis very differently. In a second step, the conclusions obtained analytically could be confirmed by analysing experimental attenuation spectra with slightly changed material property data. The paper is intended to give users of ultrasonic spectroscopy a practical guide for deciding which material properties have to be obtained with high accuracy and which can be estimated. : S 0 9 2 7 -7 7 5 7 ( 0 0 ) 0 0 5 7 1 -9

Bone ablation using different pulse parameters and four emission lines of 9.3, 9.6, 10.3, and 10.6 μm of the CO2 laser exhibits effects which are caused by the thermal properties and the absorption spectrum of bone material. The ablation mechanism was investigated with light- and electron-microscopy at short laser-pulse durations of 0.9 and 1.8 μs and a long pulse of 250 μs. It is shown that different processes are responsible for the ablation mechanism either using the short or the long pulse durations. In the case of short pulse durations it is shown that, although the mineral components are the main absorber for CO2 radiation, water is the driving force for the ablation process. The destruction of material is based on explosive evaporation of water with an ablation energy of 1.3 kJ/cm3. Histological examination revealed a minimal zone of 10–15 μm of thermally altered material at the bottom of the laser drilled hole. Within the investigated spectral range we found that the ablation threshold at 9.3 and 9.6 μm is lower than at 10.3 and 10.6 μm. In comparison the ablation with a long pulse duration is determined by two processes. On the one side, the heat lost by heat conduction leads to carbonization of a surface layer, and the absorption of the CO2 radiation in this carbonized layer is the driving force of the ablation process. On the other side, it is shown that up to 60% of the pulse energy is absorbed in the ablation plume. Therefore, a long pulse duration results in an eight-times higher specific ablation energy of 10 kJ/cm3.

This work details the fabrication and performance of a sensor for ammonia gas analysis which has been constructed via the inkjet-printed deposition of polyaniline nanoparticle films. The conducting films were assembled on interdigitated electrode arrays and characterised with respect to their layer thickness and thermal properties. The sensor was further combined with heater foils for operation at a range of temperatures. When operated in a conductimetric mode, the sensor was shown to exhibit temperaturedependent analytical performance to ammonia detection. At room temperature, the sensor responded rapidly to ammonia (t 50 = 15 s). Sensor recovery time, response linearity and sensitivity were all significantly improved by operating the sensor at temperatures up to 80 • C. The sensor was found to have a stable logarithmic response to ammonia in the range of interest (1-100 ppm). The sensor was also insensitive to moisture in the range from 35 to 98% relative humidity. The response of the sensor to a range of common potential interferents was also studied.

Phosphorus-containing wholly aromatic thermotropic liquid crystalline polymer (TLCP) reinforced poly(butylene terephthalate) (PBT) composites were prepared. Dynamic rheological analysis displayed that the addition of TLCP led to the decrease of the complex viscosity of PBT. While the thermal stability and tensile modulus were found to be increased distinctly, the results of dynamic mechanical analysis, isothermal crystallization, and morphological observation indicated that these changes were related to the rigid chains and in situ fibrillation of TLCP phase, and the interfacial adhesion between PBT and TLCP.

Loop heat pipes (LHPs) are heat transfer devices whose operating principle is based on the evaporation/condensation of a working fluid, and which use the capillary pumping forces to ensure the fluid circulation. Their major advantages as compared to heat pipes are an ability to operate against gravity and a greater maximum heat transport capability. In this paper, a literature review is carried out in order to investigate how various parameters affect the LHP operational characteristics. This review is based on the most recent published experimental and theoretical studies. After a reminder of the LHP operating principle and thermodynamic cycle, their operating limits are described. The LHP thermal resistance and maximum heat transfer capability are affected by the choice of the working fluid, the fill charge ratio, the porous wick geometry and thermal properties, the sink and ambient temperature levels, the design of the evaporator and compensation chamber, the elevation and tilt, the presence of non-condensable gases, the pressure drops of the fluid along the loop. The overall objective for this paper is to point the state-of-the-art for the related technology for future design and applications, where the constraints related to the LHPs are detailed and discussed.

Using an electronic apparatus simulating a bird roosting in a nest at night, we examined the insulating qualities of Eurasian Tree Sparrow (Passer montanus) nests built in nest boxes under winter conditions. Nests of different construction were compared with an empty box, and with roosting in open air. Energy savings in an empty box accounted for 18%, in boxes with

The main objective of this work is to present a method for measuring the specific heat of single metallic, carbon, and ceramic fibers at very high temperature. The difficulty of the measurement is due to the microscale of the fiber ͑Ϸ10 m͒ and the important range of temperature ͑700-2700 K͒. An experimental device, a modelization of the thermal behavior, and an analytic model have been developed. A discussion on the measurement accuracy yields a global uncertainty lower than 10%. The characterization of a tungsten filament with thermal properties identical to those of the bulk allows the validation of the device and the thermal estimation method. Finally, measurements on carbon and ceramic fibers have been done at very high temperature.

Ru III complexes of the type [RuX(L) 2 (E)] (X ¼ Cl or Br; L ¼ novel bidentate Schiff base ligand; E ¼ PPh 3 or AsPh 3 ) have been prepared by reacting [RuX 3 (E) 3 ] or [RuBr 3 (PPh 3 ) 2 (MeOH)] with two novel bidentate Schiff base ligands derived from 4-(1-methyl-1-mesitylcyclobutane-3-yl)-2-aminothiazole, in a 1:2 molar ratio in benzene, and characterised by analytical, spectral (i.r., electronic, 1 H-, 13 C-n.m.r., and e.p.r.) and electrochemical data. An octahedral structure has been tentatively proposed for all the new complexes. The thermal properties of the ligands and their complexes have been studied by t.g.a. The new Ru III complexes are effective catalysts for the oxidation of alcohols to carbonyl compounds but are unable to oxidise alkenes in the presence of N-methylmorpholine-N-oxide (NMO) as co-oxidant. The antimicrobial activity of the ligands and complexes have also been tested against six microorganisms.

Two series of organic–inorganic hybrid films were prepared from epoxidised castor oil (ECO) and the inorganic precursor 3-aminopropyltriethoxysilane (APTES), and the combination of APTES with tetraethoxysilane (TEOS) with different organic to inorganic proportions. Films were pre-cured at room temperature under inert atmosphere and subsequently submitted to thermal curing. The macro- and microscopic properties of the films, including adhesion, hardness, microstructure and thermal properties, were determined as a function of the proportion of ECO to inorganic precursors. Morphologic studies showed that the hybrid films were microscopically homogeneous. The hardness and tensile strength of the films increased with increased concentrations of inorganic precursor. All of the films exhibited good adhesion to an aluminium surface and worked as an efficient barrier against corrosion.

In this work the thermal analysis of raw and defatted sisal fiber and its chemical constituents (cellulose, hemicellulose and lignin) was performed by thermogravimetric analysis, and differential scanning calorimetry under air and nitrogen atmospheres. The DSC studies showed that the degradation process depends on the atmosphere involved. In inert atmosphere, the DSC curves exhibited distinct peaks for sisal fiber and its constituents, whereas in air atmosphere the thermal curves presented two exothermic peaks for all the constituents. The degradation of cellulose in inert atmosphere occurred by endothermic processes whereas, in air atmosphere, it occurred by exothermic processes. TGA measurements corroborated the results obtained by DSC. It is shown that cellulose and hemicellulose degraded at lower temperatures than that of the raw sisal fiber, which can be attributed to the removal of lignin. The thermal decomposition of sisal fiber and its constituents was discussed and compared to jute and hemp fibers.

The 3 method has been proven to be very useful for determining the thermal conductivity of thin films and their substrates. Several simplifications are often used in determining the thermal conductivity of the films based on the experimentally measured 3 signal. These simplifications, however, have limited range of applicability. In this work, we present a detailed analysis and mathematical modeling of the 3 method applied for different experimental conditions. Effects considered include the finite substrate thickness, anisotropic nature of the film and substrate thermal conductivity, the film-substrate thermal property contrasts, the effect of heat capacitance of the heater, and the effect of thermal boundary resistance. Several experimental results are analyzed using the models presented. This work shows that the 3 method can be extended to a wide range of sample conditions, with anisotropic conductivities in both the substrate and the film, and with small film-substrate conductivity contrast.

BACKGROUND: Frozen blood components are shipped on dry ice. The lower temperature (-70°C in contrast to usual storage at-30°C) and shipping conditions may cause a rent in the storage bag, breaking sterility and rendering the unit useless. The rate of loss can reach 50 to 80 percent. To identify those bags with lower probability of breaking during shipment, the thermal and physical properties of blood storage bags were examined. STUDY DESIGN AND METHODS: Blood storage bags were obtained from several manufacturers and were of the following compositions: PVC with citrate, di-2-ethylhexylphthalate (DEHP), or tri-2-ethylhexyl-tri-mellitate (TEHTM) plasticizer; polyolefin (PO); poly(ethylene-covinyl acetate) (EVA); or fluorinated polyethylene propylene (FEP). The glass transition temperature (Tg) of each storage bag was determined. Bag thickness and measures of material strength (tensile modulus [M T ] and time to achieve 0.5 percent strain [T 0.5% ]) were evaluated. M T and T 0.5% measurements were made at 25 and-70°C. Response to applied force at-70°C was measured using an impact testing device and a drop test. RESULTS: The Tg of the bags fell into two groups: 70 to 105°C (PO, FEP) and-50 to-17°C (PVC with plasticizer, EVA). Bag thickness ranged from 0.14 to 0.41 mm. Compared to other materials, the ratios of M T and T 0.5% for PVC bags were increased (p Յ 0.001) indicating that structural changes for PVC were more pronounced upon cooling from 25 to −70°C. Bags containing EVA were more shock resistant, resulting in the lowest rate of breakage (10% breakage) when compared with PO (60% breakage, p = 0.0573) or PVC (100% breakage, p = 0.0001). CONCLUSIONS: Blood storage bags made of EVA appear better suited for shipping frozen blood components on dry ice and are cost-effective replacements for PVC bags. For the identification of blood storage bags meeting specific storage requirements, physical and thermal analyses of blood storage bags may be useful and remove empiricism from the process. ABBREVIATIONS: DEHP = di-2-ethylhexylphthalate; EVA = poly(ethylene-covinyl acetate); FEP = fluorinated ethylene propylene; FRBC(s) = frozen RBC(s); PBPC(s) = peripheral blood progenitor cell(s); PO = polyolefin; TEHTM = tri-2-ethylhexyltri-mellitate; Tg = glass transition temperature.

An automatic cloud cover assessment algorithm was developed for the Landsat 7 ground system. A scene dependent approach that employs two passes through ETM+ data was developed. In pass one, the reflective and thermal properties of scene features are used to establish the presence or absence of clouds in a scene. If present, a scene-specific thermal profile for clouds is established. In pass two, a unique thermal signature for clouds is developed and used to identify the remaining clouds in a scene. The algorithm appears to be a good cloud discriminator for most areas of the Earth. Some difficulty has appeared in imagery over Antarctica, and snow at high illumination angles is occasionally mistaken for cloud.

Ultra-thin fibers are obtained from polyacrilonitrile co-polymer (PAN-CP)/N,N-dimethylformamide (DMF) solution by electro-spinning technique. The different wt. content of PAN-CP solution is electrospun with varying processing parameters to get nanofibers. The morphology of nanofibers is studied by scanning electron microscopy (SEM) and thermal properties are primarily investigated by DSC and TGA. The polymer nanofibers are stabilized and carbonized to get carbon nanofibers, after stabilization and carbonization nanofibers are characterized by FTIR, XRD, SEM and SPM. It is found that the diameter of nanofibers varies from 150 to 1300 nm, that increases with increasing polymer concentration and decreases with increasing the tip to collector distance and collector speed. The DSC studies show that the exothermic peak occurs at two different temperatures 275 and 320 °C in case of nanofibers. While in case of micron fiber single exothermic peak occurs at ∼275 °C. This might be due to the alignment of polymeric chain along the fiber direction. This is due to the stretching and whipping that occurs during the electrospinning process. As a consequence, increase in thermal stability and decrease in weight of nanofibers is confirmed by TGA. However, in the nanofibers of diameter >1000 nm, weight loss pattern is found to be similar as that of micron fibers. This could be due to the entrapping of solvent between polymeric chains. On stabilization and carbonization there is a decrease in fiber diameter in all the cases. The extent of decrease is higher in case of 10 wt.% electrospun fibers, from 350–400 nm to 100 nm. The SPM investigations reveal that the surface area and roughness changes due to the transverse shrinkage of nanofibers.

Microencapsulation of Lippia sidoides essential oil was carried out by spray drying. Blends of maltodextrin and gum arabic were used as carrier. Spray dried microparticles were characterized using conventional (thermogravimetry, evolved gas analysis) and combined (thermogravimetry-mass spectrometry analysis) thermal analysis techniques in order to evaluate the abilities of carriers with different compositions in retaining and in releasing the core vs. dynamic heating. Thermal analysis was useful to evaluate the physico-chemical interactions between the core and carriers and to determine the protective effect of the carriers on the evaporation of essential oil.

We review the theory and applications of the photoacoustic and related methods belonging to the general area of photothermal measurement techniques. This essay is intended for researchers especially unfamiliar with the basic ideas and potentialities of this rapidly developing field. The applications of photothermal techniques include spectroscopic applications, such as infrared and microwave spectroscopies, monitoring of non-radiative deexcitation processes, biological applications, and measurements of thermal properties.

Rosin and beeswax are two complex natural materials presenting numerous applications in paints, adhesives, varnishes or inks. Melted, they are particularly interesting for their adhesion properties. This paper establishes the first phase diagram beeswax/rosin blends. A systematic approach using X-ray diffraction (XRD), differential scanning calorimetry (DSC) and polarised optical microscopy (POM) has been performed in order to describe the crystallographic structure and the thermal properties of two materials, beeswax and rosin, and their blends. Indeed, melting, softening and crystallisation temperatures, polymorphic transitions but also crystalline index has been investigated. The resulting phase diagram reveals a complex behaviour in terms of phase transformation and time-dependent phenomenon mainly representative of the complex composition of beeswax.

In this work, typical polybenzoxazine, as new class of phenolic resin, has been used as a matrix for preparing a series of high performance hybrid materials using various amounts of titanium carbide (TiC) ranging between 0-10 wt% as fillers, via a solution blending technique. The thermal properties of bisphenol A-aniline base benzoxazine monomers (BA-a) and TiC mixtures have been studied by differential scanning calorimetry (DSC). The thermal stability of their cured hybrids has been tested by means of thermogravimetric analysis (TGA). The result showed that the glass transition temperature of the prepared composites increased with increasing the amount of TiC to reach a higher value at 194°C. Also, the incorporation of TiC nanoparticles has considerably improved the thermal stability of the hybrids including the char yield which increase by 50 % at 10 wt% TiC content.

The influence of adding waste wax, produced as a by-product of the low density polyethylene manufacturing process, on the thermal and mechanical properties of three types of polyethylene (PE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE), with 10, 20, 30 and 40 wt.% was investigated. Polymerwax mixing was effective with no apparent leakage of the wax during sample preparation, which was evident from the agreement between the theoretical and experimental values of enthalpy for all types of PE.

We present experimental evidence that the room temperature thermal conductivity (κ) of individual multiwall carbon nanotubes and boron-nitride nanotubes does not obey Fourier's law as do ordinary thermal conductors. By varying the length (L) of the nanotube, we find that κ diverges as L 0.6∼0.9 . Our results show that Fourier's law is violated despite the fact that the ballistic phonon condition is not satisfied and large isotopic disorder is present.