Adsorption isotherms of pigments from alkali-refined vegetable oils with clay minerals

Adsorption isotherms of pigments from alkali-refined oils (rapeseed, soybean, wheatgerm, safflower, corn, cottonseed and sunflower) were measured to investigate the applicability of the Langmuir and Freundlich equations and to elucidate the adsorption characteristics of pigments on sepiolites and standard activated clay. The Freundlich equation was more applicable to the experimental adsorption isotherms. The equilibrium amount adsorbed, acidity, pore size distribution and inflection of the Freundlich isotherms could be explained by assuming that pigments were adsorbed on the stronger acid sites in smaller pores at low concentration, and then in the larger ones when the concentration increased. The amount adsorbed increased with a rise in adsorption temperatures from 70 to 110°C, and the heat of adsorption was below 10 kcal/mol. The results indicate that pigments were physically adsorbed on the acid sites activated at higher adsorption temperatures.     

Colorimetric microdetermination of sulphites in foods by use of the modified rankine apparatus. IV.

Summary Detection and determination of traces of sulphites in foods was attempted by use of the modified Rankine apparatus and pararosaniline colorimetry. Replacement of alkaline titration reported previously by pararosaniline colorimetry lowered the absolute detection limit from 30 g (titration method) to 2 g. In view of clean analysis, in the color developing system, 0.1 N-sodium hydroxide was used in place of mercuric chloride solution commonly used as an absorbant of sulphites. In order to prevent oxidative decomposition of sulphites during operation, nitrogen gas was used as carrier instead of air. Dimedone and sodium azide were used for the elimination of aldehydes and nitrites, respecitvely, in the sample, which will disturb the color development of sulphites with pararosaniline-formaldehyde reagents. With this improved method, it was possible to determine the residual sulphites in frozen peeled shrimps, sugared beans and other foods with low sulphite contents accurately.

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Colorimetrische Mikrobestimmung von Sulfiten in Lebensmitteln bei Anwendung der modifizierten IV. Rankine Apparatur

Zusammenfassung Geringe Sulfitmengen in Lebensmitteln (geschälte Garnelen, gezuckerte Bohnen) können colorimetrisch bestimmt werden. Die neuentwickelte Methode beruht auf einer Kombination von colorimetrischer Bestimmung mittels p-Rosanilin und der Bestimmungsmethode nach Rankine. Auf diese Weise lassen sich Gehalte von 2 g noch genau bestimmen. Bei der Farbentwicklung wurde das giftige Quecksilbertetrachlorid durch 0.1 n-NaOH ersetzt, anstelle von Luft Stickstoff als Trägergas verwendet und somit eine Oxydation des Sulfits während der Bestimmung vermieden. Da Nitrit und Aldehyde die Farbentwicklung stören, wurde ihr Einfluß durch Dimedon und Natriumazid ausgeschaltet.

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Studies on the Analyses of Sulphites in Foods (IV)     

Analysis of accelerated creep under constant sustaining load for austenitic stainless steels

The effect of stress on creep rate of austenitic stainless steels of type 347 and 316 was studied by applying the differential test technique. It was found that the creep rate could be expressed as follows, whereB ₁ is a material constant depending on temperature,a ₁ anda _o are constants, and σ is the real stress. Considering the increase in real stress during creep process due to void formation and to the decrease in cross sectional area of the specimen, integrating the above equation yields the following creep curve, 1 $$ \in = \in _m + \frac{1}{{n_o \left( {c_o + 1} \right)}}ln\frac{1}{{1 - n_o \left( {c_o + 1} \right) \in _m (t - t_{_m } )}}$$ where ∈ is the creep strain at a given time (t), ∈_m is the minimum creep rate, ∈_m andt _m are the strain and time, respectively, at the minimum creep rate,n _o is a constant, andc _o is the material constant relating to the void formation. This equation agrees very well with the experimental creep curve.     

Hot-water treatment of sol–gel derived SiO2–TiO2 microparticles and application to electrophoretic deposition for thick films

SiO₂–TiO₂ spherical microparticles of about 0.7 μm in diameter were prepared by the sol–gel method. Anatase nanocrystals were formed in the microparticles and their specific surface area was increased after a hot-water treatment at 90 °C. From the changes in the concentration of I₂ photocatalytically generated from KI aqueous solution, the activity of the SiO₂–TiO₂ microparticles was found to increase with increasing the hot-water treatment time. Particulate, thick films were electrophoretically deposited on indium tin oxide (ITO)-coated glass substrates using the anatase nanocrystal-precipitated SiO₂–TiO₂ microparticles. The thickness of the electrophoretically deposited particulate film increased to be approximately 10 μm with an increase in applied voltage. The resultant thick film showed a high photocatalytic activity.     

Experimental study of perforation and cracking of water-filled aluminum tubes impacted by steel spheres

Water-filled aluminum tubes were subjected to impact by six steel spherical projectiles of different diameters at impact velocities of 40–200 m/s. The effects of the diameter of the steel projectiles and of the material properties of the tubes on cracking and perforation were discussed. Water decreased the wall strength of the aluminum alloy tubes, and the impact velocity at which a steel projectile first passes through the tube wall decreased with increasing diameter of the steel projectile. Using the velocity at which the steel projectile perforates the tube wall, empirical equations of the energies required to perforate the tube wall were derived. Also, the energy balance in the steel projectile during a collision is discussed referring to the pressure history in the filled water and the velocities of the steel projectile before and after collision.     

Growth and structure of heteroepitaxial thin films of homologous compounds RAO3(MO)m by reactive solid-phase epitaxy: Applicability to a variety of materials and epitaxial template layers

A reactive solid-phase epitaxy (R-SPE) method combines deposition of a thick amorphous or polycrystalline layer with a desired chemical composition and post-deposition solid-phase epitaxial growth. The solid-phase epitaxial growth is invoked by thermal annealing with an assistance of a sacrificial layer working as an epitaxial template. Thereby it enables us to grow high-quality epitaxial films of complex oxides whose epitaxial films are not grown by conventional high-temperature growth techniques. It was reported that 2-nm-thick ZnO layers worked as template for growing InGaO₃(ZnO)_m (m = integer) epitaxial films. The present study extended the R-SPE technique to growth of various complex oxides with chemical compositions of RAO₃(MO)_m and to use of various epitaxial template layers. We found that mono oxide epitaxial layers such as In₂O₃ and Ga₂O₃ work as template layers as well. Alternatively, a ZnO epitaxial layer is also applicable to ZnO-free compounds. The films obtained were grown heteroepitaxially on YSZ(111) and single-crystalline when the fabrication conditions are optimized.     

Satellite-Based Energy Balance to Assess Within-Population Variance of Crop Coefficient Curves

Quantifying evapotranspiration (ET) from agricultural fields is important for field water management, water resources planning, and water regulation. Traditionally, ET from agricultural fields has been estimated by multiplying the weather-based reference ET by crop coefficients (Kc) determined according to the crop type and the crop growth stage. Recent development of satellite remote sensing ET models has enabled us to estimate ET and Kc for large populations of fields. This study evaluated the distribution of Kc over space and time for a large number of individual fields by crop type using ET maps created by a satellite based energy balance (EB) model. Variation of Kc curves was found to be substantially larger than that for the normalized difference vegetation index because of the impacts of random wetting events on Kc, especially during initial and development growth stages. Two traditional Kc curves that are widely used in Idaho for crop management and water rights regulation were compared against the satellite-derived Kc curves. Simple adjustment of the traditional Kc curves by shifting dates for emergence, effective full cover, and termination enabled the traditional curves to better fit Kc curves as determined by the EB model. Applicability of the presented techniques in humid regions having higher chances of cloudy dates was discussed.     

Microgravity performance of micro pulsating heat pipes

A micro pulsating heat pipe made of a thin clear Teflon tube of 1.6 mm ID was used to observe the pulsating flow inside a heat pipe under different gravity levels using parabolic flights. More vigorous pulsating flow was observed under microgravity, compared to the depressed movements under hypergravity. Two metallic micro pulsating heat pipes made of an aluminum plate with small internal channels were also tested to investigate the effect of gravity on their heat transfer characteristics. Reduced gravity experiments were performed aboard Falcon 20 aircraft flying parabolic trajectories. Under normal and hypergravity conditions, both the orientation of the pulsating heat pipe and locations of the heated and cooled sections affected the heat transfer performance. Under reduced gravity, however, the heat pipes showed better operating and heat transfer performance than that under normal and hypergravity. These experiments have for the first time confirmed that pulsating heat pipes are capable of operating under reduced gravity and thus are suitable for deployment in space applications such as satellites.     

ISS experiments for the clarification of boiling and two-phase flow in microgravity and for the development of high-performance space cold plates

Inflow boiling, gravity effects on the distribution of both phases are observed in a heated tube and heat transfer coefficients due to two-phase forced convection is deteriorated in microgravity. In narrow channels between heated and unheated plates, the increase in subcooling enlarges a size of flattened bubble and reduces the frequency of detachment under microgravity conditions resulting the emphasis of heat transfer deterioration. To clarify reasons for the unknown behaviors of interfacial distribution and corresponding characteristics in heat transfer not easily be clarified through the experiments on ground, the opportunity on the experiments utilizing long-term microgravity duration realized in ISS is required. The experiments on microgravity boiling and two-phase flow are proposed by the collaboration of researchers in five countries. A common test loop is designed to conduct multiple experiments by the interchangeable structures of test sections; a transparent heated tube for the visualized flow boiling, a stainless tube for the measurement of CHF data, a copper surface for the heat transfer data of nucleate boiling with superimposed liquid flows in a duct, a glass heated plate with multiple array of small temperature sensors and transparent heaters for the clarification of mechanisms in nucleate boiling heat transfer, and one or two models of cold plates for practical applications. A direction of researches in the present discipline is proposed based on the existing experimental results and on the idea developed by the present authors.     

Control and design problems in material processing—how can process systems engineers contribute to material processing?

‘Process control and systems engineering’ is not just a subject of study for controlling and designing ‘a plant’ and/or ‘a unit operation’. It also deals with any control and design problems related to physical and chemical phenomena occurring in short time-scale and at nano, meso as well as micro-scale levels. In materials processing, controlling the material structure is of primary importance for realizing high material performance and functions. The phenomena determining the material structure often involve phase separation and/or occur on the surface of the materials, at small level and in short time-scale. To control these phenomena, the current feedback design schemes, where controlled variables are measured by ‘externally equipped sensors’ and fed back to a ‘externally designed controller’, are no longer effective due to the shortness of time and smallness of spatial scales of the objects. Making reference to two novel polymer-processing processes, a micro-cellular polymeric foaming process and surface coating injection-molding process, we discuss how process control and process systems engineers can contribute to controlling the structure of materials.