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  • 1
    Electronic Resource
    Electronic Resource
    Insulating, metallic, or semimetallic electronic nature of XSi2 compounds: Application to WSi2 (1987)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 62 (1987), S. 890-895 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present a model which gives a simple interpretation of already published band-structure calculations in transition-metal disilicides (i.e., XSi2, where X stands for Co, Ni, Cr, or W). This approach, based on wave function symmetries, gives physical insight on the insulating, metallic, or semimetallic electronic nature of these silicides. In this theoretical frame, WSi2 is predicted to be a strictly compensated semimetal. Extensive electrical measurements performed on various WSi2 thin films are consistent with this prediction and indicate that the free-carrier density is less than 3×1021 cm−3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.339695
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  • 2
    Electronic Resource
    Electronic Resource
    Phosphorus redistribution in a WSi2/polycrystalline-silicon gate structure during furnace annealing (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 63 (1988), S. 732-742 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The phosphorus redistribution in a WSi2/polycrystalline-silicon structure after furnace annealing between 600 and 1000 °C was studied. When P is initially introduced into the polycrystalline-silicon, a secondary ion mass spectroscopy analysis shows a nearly equidistribution of the dopant within the sandwich. When the silicide layer is phosphorus implanted, it has been clearly shown that with the refractory metal the dopant forms a tungsten phosphide compound more stable than WSi2 up to a critical temperature Tc. The stability of the phosphide increases with the implanted dose. A complete characterization of the additional phase was obtained by thermal annealing of W-Si-P powders. Several other interesting features on the redistribution of the dopant in the polycrystalline-silicon/silicide structure have been established and discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.340065
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  • 3
    Electronic Resource
    Electronic Resource
    Thermal evolution of molybdenum disilicide grown on (100) silicon under ultrahigh vacuum conditions (1986)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 59 (1986), S. 2760-2764 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Under ultrahigh vacuum conditions, molybdenum disilicide has been obtained by electron gun evaporation of molybdenum on heated monocrystalline silicon substrate. Depending on the deposition temperature, the resulting thin film is composed of tetragonal disilicide or of a mixture of hexagonal and tetragonal disilicide. Preferential orientations of MoSi2 have been observed for both phases grown on (100) silicon substrate heated at 550, 650, and 750 °C. Further annealing does not improve the crystallographic orientation of the materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.337048
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  • 4
    Electronic Resource
    Electronic Resource
    SORBIC ACID STABILITY DURING PROCESSING and STORAGE OF AN INTERMEDIATE MOISTURE CHEESE ANALOG (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food processing and preservation 13 (1989), S. 0 
    Details
    ISSN: 1745-4549
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The chemical stability of sorbic acid during processing and storage of intermediate moisture foods was determined using a soybean based cheese analog. Samples prepared with 0.57 to 4.24% homogeneously distributed K-sorbate showed losses of less than 25% after 40 days storage at 35°C, 88% RH air and in the dark. Heating (2 h in an 85°C water bath) resulted in no significant sorbic acid losses. Samples with surface applications of 1 mg sorbic acid/cm2 showed no detectable losses after 10 days storage under the same conditions. Furthermore, the stability of the preservative was not affected by growth of Staphylococcus aureus S-6.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1745-4549.1989.tb00115.x
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  • 5
    Electronic Resource
    Electronic Resource
    MICROBIAL STABILIZATION OF INTERMEDIATE MOISTURE FOOD SURFACES I. CONTROL OF SURFACE PRESERVATIVE CONCENTRATION (1985)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food processing and preservation 9 (1985), S. 0 
    Details
    ISSN: 1745-4549
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Changing environmental conditions to which intermediate moisture foods (IMF's) are exposed during production, storage, distribution and use, are important microbial stability factors. Temperature changes result in local surface condensations leading to microbial outgrowth on the surface. An approach to improved surface stability using a high preservative surface concentration maintained by an impermeable edible food coating was developed. Permeability tests predicted that zein was an acceptable coating. Sorbic acid distribution experiments confirmed its barrier properties. Apparent diffusion coefficient was estimated between 3 and 7 × 10−9 cm2/s. These values were 150–300 times smaller than the value measured in the bulk of the IMF model food system used in this study, 10−6 cm2/s.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1745-4549.1985.tb00711.x
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  • 6
    Electronic Resource
    Electronic Resource
    MICROBIAL STABILIZATION OF INTERMEDIATE MOISTURE FOOD SURFACES II. CONTROL OF SURFACE pH (1985)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food processing and preservation 9 (1985), S. 0 
    Details
    ISSN: 1745-4549
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper explores the possibility of reducing surface pH to solve intermediate moisture foods microbial stability problems associated with localized surface condensations caused by temperature fluctuations. Surface pH reduction increases surface availability of the most active form of sorbic acid and other lipophilic acids used as preservatives.A negatively charged macromolecule was immobilized in the form of a food surface coating component while other molecules, particularly electrolytes, move freely. The effect on surface pH was described using a Donnan equilibrium model that predicted a permanent pH difference between surface and food bulk. The key parameters were electrolyte concentration and the concentration of charged groups on the macromolecule. An IMF model with low total electrolyte concentration was coated with a deionized mixture of λ-carrageenan and agarose. Measured pH differential was 0.3 to 0.5 pH units. Such a pH reduction resulted in a calculated 2.5 fold increase in the surface availability of the active form of sorbic acid as compared to food bulk conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1745-4549.1985.tb00712.x
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  • 7
    Electronic Resource
    Electronic Resource
    MICROBIAL STABILIZATION OF INTERMEDIATE MOISTURE FOOD SURFACES III. EFFECTS OF SURFACE PRESERVATIVE CONCENTRATION AND SURFACE pH CONTROL ON MICROBIAL STABILITY OF AN INTERMEDIATE MOISTURE CHEESE ANALOG (1985)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food processing and preservation 9 (1985), S. 0 
    Details
    ISSN: 1745-4549
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Localized surface condensations affect microbial stability of intermediate moisture foods (IMF). Two surface modifications previously reported were tested for their ability to improve microbial surface stability; control of surface preservative concentration and reduced surface pH.The effectiveness of a high surface sorbic acid concentration controlled by a zein coating was confirmed in Staphylococcus aureus S-6 surface challenge experiments under extreme testing conditions. Samples with bulk water activity (aw) of 0.88, stored at 30°C under constant 88% relative humidity (RH) remained stable for over 16 days. Uncoated controls were stable for only 2 days. Samples with bulk aw = 0.85, exposed to cycles of 12 h at85% RH and 12h at 88% RH, remained stable for more than 28 days. Uncoated controls were stable for only 3 days.The reduced surface pH approach to microbial stability required the formulation of an IMF model with low total electrolyte concentration which was coated with a deionized mixture of λ-carrageenan and agarose. The effectiveness of the resulting 2.5 fold increase in the surface availability of the active form of sorbic acid as compared to food bulk was confirmed in a challenge test with S. aureus S-6. In a test with samples at aw = 0.88, stored at RH = 88% and 30°C, we found a stability period of about 20 days and it seems possible to increase it.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1745-4549.1985.tb00713.x
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  • 8
    Electronic Resource
    Electronic Resource
    POTASSIUM SORBATE PERMEABILITY of METHYLCELLULOSE and HYDROXYPROPYL METHYLCELLULOSE MULTI-LAYER FILMS (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food processing and preservation 13 (1989), S. 0 
    Details
    ISSN: 1745-4549
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Spoilage by microorganisms growing on food surfaces is the shelf-life limiting factor for many food products. Previous publications have shown that this shelf-life limitation can be overcome by edible coatings lowering the diffusion rate into the food of antimicrobial agents applied on food surfaces. A permeability cell has been used to evaluate the potassium sorbate barrier properties of polysaccharide based films. In this paper we examine the effect of film formation technique and film formulation on the permeability rate of methyl- and hydroxy-propyl methyl cellulose based films. Permeability constant determinations ranging from 10−9 to 1011 (mg/s cm2)(cm)/(mg/cm3) indicate that surface resistance to microbial growth could be enhanced significantly. Scanning electron microscopy examinations showed that films were of uniform thickness. Morphological differences between films were consistent with permeability measurements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1745-4549.1989.tb00116.x
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  • 9
    Electronic Resource
    Electronic Resource
    Sterilization of Conduction-Heated Foods in Oval-Shaped Containers (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 54 (1989), S. 0 
    Details
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A finite difference approximation of the differential equation for transient heat conduction in three dimensions was used to evaluate thermal processes for foods in oval-shaped containers. A sensitivity analysis on the basis of thiamin retention was used to select the time increment and the size of the volume elements required by the numerical method. Estimations of the temperature for the center of the oval container were in close agreement with an analytical solution valid for sufficiently long times, constant boundary conditions, and uniform initial temperature. To validate the model, published experimental data for the retention of thiamin, chlorophyll and betanin were compared with values predicted by the numerical method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1989.tb05984.x
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  • 10
    Electronic Resource
    Electronic Resource
    Propulsion efficiency and cost of transport for copepods: a hydromechanical model of crustacean swimming (1985)
    Springer
    Marine biology 86 (1985), S. 283-295 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the absence of direct measurement, costs of locomotion to small swimming Crustacea (〈10 mm) have been derived exclusively through application of the fluid dynamic theory. Results indicate very low swimming costs, and contradict experimental data on larger Crustacea (15 to 100 mm) that suggest a three-fold increase in metabolic rate with increasing swimming speed. This paper introduces a swimming model that analyzes the hydrodynamic forces acting on a crustacean swimming at non-steady velocity. The model treats separately the hydrodynamic forces acting on the body and the swimming appendages, approximating the simultaneous solution of equations quantifying the drag and added-mass forces on each by stepwise integration. Input to the model is a time-series of instantaneous swimming-appendage velocities. The model output predicts a corresponding time-series of body velocities as well as the mechanical energy required to move the swimming appendages, dissipated kinetic energy, and metabolic cost of swimming. Swimming of the calanoid copepod Pleuromamma xiphias (Calanoida) was analyzed by extrapolating model parameters from data available in the literature. The model predictions agree well with empirical observations reported for larger crustaceans, in that swimming for copepods is relatively costly. The ratio of active to standard metabolism for P. xiphias was 〉3. Net cost of transport was intermediate to the values found experimentally for fish and larger crustaceans. This was a consequence of the predicted mechanical efficiency (34%) of the copepod's paddle propulsion, and of increased parasitic resistance resulting from non-steady velocity swimming.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397515
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