1,800 research outputs found
Current Status And Problems Of The Sawmilling Industry In Thailand A Case Study In Bangkok Metropolitan Area
Sawmilling industry in Thailand lack the technical
information and data for improving the sawmill in goperation . Futhermore , severe log short age results to the
forced shut -down / closure of several sawmills .In an effort
to help solve these problems , this study was conducted to
determine the current status and identify the problems
faced by these sawmills . Based on the survey and field
visits , the major problems included short age of raw
material and flexible government policy.Most of the
sawmills were very primitive and ill- equipped coupled with
limited skilled lab our resulting to high production cost ,
low productivity rate and low recovery rate . There is also
additional research and development that need to be carried
out and advisory services to be provided to the sawmilling
industry .The government must review its policies to wards
promoting modern equipment and technology by giving
supports through financing and training programs . Both
government and private sectors must joint together in helping and upgrading the plight s o f the sawmills
Evanescent Field Coupling Theory of a D-Fibre
This thesis describes theoretically the evanescent coupling of a D-fibre, with the aim of calculating the propagation constants of the transverse modes. Both analytical and numerical methods are considered for the study of coupling situations involving a fibre. The first analytical method, Coupled Mode Theory (CMT), provides an understanding of the coupling phenomenon which occurs between two similar guides. In this situation, for example, for two fibres/guides with a similar range of propagation constants, coupling does not occur between a guided mode of the first guide and a radiation mode of the second. However, plane wave analysis is preferred to CMT for its simplicity and adequacy in prism coupling application. Secondly, the GF method is selected as the appropriate numerical method for the case of a D-fibre coupled to a semi-infinite dielectric medium, in preference to the point matching and finite elements methods. The GF method (a semi-numerical method) leads to an eigenvalue problem, with the propagation constant as the only unknown. The behaviour of the GF is dependent on the refractive index of the medium surrounding the fibre, the distance from the core to the flat surface of the cladding, and the possible effective refractive indices of the guided modes. A program is developed to calculate the GF as a function of these variables. By defining these parameters, it enables the testing of several routines which could be later introduced into a final program calculating the different propagation constants of the guiding structure. Finally, the analytical study has been extended to allow direct application in the final program
La communication avec des patients non francophones: travailler en trialogue lors de prises en charge de personnes étrangères dans les hôpitaux : revue de la littérature
Ce travail s’intéresse à la communication entre soignants et patients non franco- phones dans un milieu hospitalier. Il met en avant l’un des moyens utilisés pour se com-prendre : l’utilisation d’interprètes professionnels (le travail en trialogue). Cette revue de la littérature a pour objectifs de nommer et examiner les moyens de communication utilisés dans les hôpitaux lors de la prise en charge d’un patient non francophone ainsi que rele-ver les avantages et inconvénients de ces différentes techniques (principalement l’utilisation d’interprètes), dans le but d’arriver à une prise en charge optimale de ces pa-tients en milieu hospitalier et d’améliorer la qualité des soins dispensés
Spin-locking effect in the nanoscale ordered perovskite cobaltite LaBaCo2O6
A new nanoscale ordered perovskite cobaltite, which consists of 90 degree
ordered domains of the layered-112 LaBaCo2O6 has been evidenced by high
resolution- transmission electron microscopy. This new form, like the
disordered La0.5Ba0.5CoO3 and ordered LaBaCo2O6, exhibits a ferromagnetic
transition at TC around 179 K. However, it differs from the two previous forms
by its strong magnetic anisotropy, and correlatively by its high value of
coercivity (0.42 Tesla) at low temperature. We suggest that this behaviour
originates from the locking of magnetic spins in the 90 degree oriented
nano-domain. Moreover, one observes a semi-metal/semi-metal transition at TC
with a maximum magnetoresistance of 6.5 % at this temperature.Comment: 16 pages including figure
Electronic Correlations in CoO2, the Parent Compound of Triangular Cobaltates
A 59Co NMR study of CoO2, the x=0 end member of AxCoO2 (A = Na, Li...)
cobaltates, reveals a metallic ground state, though with clear signs of strong
electron correlations: low-energy spin fluctuations develop at wave vectors q
different from 0 and a crossover to a Fermi-liquid regime occurs below a
characteristic temperature T*~7 K. Despite some uncertainty over the exact
cobalt oxidation state n this material, the results show that electronic
correlations are revealed as x is reduced below 0.3. The data are consistent
with NaxCoO2 being close to the Mott transition in the x -> 0 limit.Comment: 4 pages, submitte
Gallium Substituted "114" YBaFe4O7: From a ferrimagnetic cluster glass to a cationic disordered spin glass
The study of the ferrites YBaFe4-xGaxO7 shows that the substitution of Ga for
Fe in YBaFe4O7 stabilizes the hexagonal symmetry for 0.40 < x < 0.70, at the
expense of the cubic one. Using combined measurements of a. c. and d. c.
magnetization, we establish that Ga substitution for Fe in YBaFe4O7 leads to an
evolution from a geometrically frustrated spin glass (for x = 0) to a cationic
disorder induced spin glass (x = 0.70). We also find an intermediate narrow
range of doping where the samples are clearly phase separated having small
ferrimagnetic clusters embedded in a spin glass matrix. The origin of the
ferrimagnetic clusters lies in the change in symmetry of the samples from cubic
to hexagonal (and a consequent lifting of the geometrical frustration) as a
result of Ga doping. We also show the presence of exchange bias and domain wall
pinning in these samples. The cause of both these effects can be traced back to
the inherent phase separation present in the samples.Comment: 25 pages, 10 figure
Anisotropic damage mechanics for viscoelastic ice
We present a formulation of continuum damage in glacier ice that incorporates the induced anisotropy of the damage effects but restricts these formally to orthotropy. Damage is modeled by a symmetric second rank tensor that structurally plays the role of an internal variable. It may be interpreted as a texture measure that quantifies the effective specific areas over which internal stresses can be transmitted. The evolution equation for the damage tensor is motivated in the reference configuration and pushed forward to the present configuration. A spatially objective constitutive form of the evolution equation for the damage tensor is obtained. The rheology of the damaged ice presumes no volume conservation. Its constitutive relations are derived from the free enthalpy and a dissipation potential, and extends the classical isotropic power law by elastic and damage tensor dependent terms. All constitutive relations are in conformity with the second law of thermodynamic
Electron transport and thermoelectric properties of layered perovskite LaBaCo2O5.5
We have investigated the systematic transport properties of the layered
112-type cobaltite LaBaCo2O5.5 by means of electrical resistivity,
magnetoresistance, electroresistance and thermoelectric measurements in various
conditions. In order to understand the complex conduction mechanism of
LaBaCo2O5.5, the transport data have been analyzed using different theoretical
models. The system shows semiconductor-semiconductor like transition (TSC)
around 326K, corresponding to ferromagnetic transition and in the low
temperature region resistivity data follows the Motts variable range hopping
model. Interestingly, near and below the room temperature this compound depicts
significant change in electro- and magnetoresistance behavior, the latter one
is noteworthy near the magnetic phase boundary. The temperature dependence of
thermopower, S(T), exhibits p-type polaronic conductivity in the temperature
range of 60-320K and reaches a maximum value of 303 uV/K (at 120K). In the low
temperature AFM region, the unusual S(T) behavior, generally observed for the
cobaltite series LnBaCo2O5.5 (Ln = Rare Earth), is explained by the electron
magnon scattering mechanism as previously described for perovskite manganites.Comment: 18 pages including fig
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