1,122 research outputs found
Oil palm leaf fibre and its suitability for paper-based products
Due to the shortage of wood as origin materials for paper-based production, agro-residue materials have been explored in the quest of finding the best alternative fibre. Oil palm leaf (OPL) is one of agro-residue that has potential due to its comparable characteristics with wood fibre. Studies on chemical compositions, fibre morphology, and mechanical property of OPL have been carried out aiming to evaluate its potential as a substitute raw material for pulp and paper-based production. The chemical compositions were analysed according to the TAPPI standard, Kurscher-Hoffner and chlorite methods accordingly. The mechanical property (tensile, tearing and bursting strengths) were determined as described in TAPPI test methods. Fibre dimensions were determined using Franklin method and analysed under the optical microscope. The content of cellulose in the OPL is determined to be 43.8%. Although, this result is lower than wood fibre (53%), OPL has higher hemicellulose content (36.4%) than the wood fibre (27.5%). In addition, the lignin content (19.7%) of OPL is in the low range of those in wood resources (18 - 25%). These parameters are important components to produce good quality pulp and will provide high mechanical strength of the paper-based products. The measured fibre length of oil palm leaf (1.13 mm) is shorter than the wood fibre (1.90 mm). Meanwhile, the mechanical property of OPL showed lower indexes than wood resources, however, tear (1.80 mN.m2/g) and burst (0.95 kPa.m2/g) indexes of OPL are higher than other published and successful wood resources (Eucalyptus). Based on the analyses, the oil palm leaf is indeed a suitable alternative of raw material for pulp and paper-based industries
A Bestiary of Higher Dimensional Taub-NUT-AdS Spacetimes
We present a menagerie of solutions to the vacuum Einstein equations in six,
eight and ten dimensions. These solutions describe spacetimes which are either
locally asymptotically adS or locally asymptotically flat, and which have
non-trivial topology. We discuss the global structure of these solutions, and
their relevance within the context of M-theory.Comment: 11 pages, LaTex(v4: Comments and references added
Exact Calculation of , \
We present an exact calculation of the Wilson coefficients
associated with the dipole moment operators. We also give an estimate of the
branching ratio for . We find that higher dimensional
effects are under control within for .Comment: 12 pages (plain TeX), 2 postscript figures available upon request.
UM-TH-93-20 , IP-ASTP-29-9
The recent advances in the nanotechnology and its applications in food processing : a review.
The objectives of this paper was to discuss the latest development of nanotechnology, especially in food industries, to give clearer picture about the effect of nanotechnology in food industries and to highlight the latest applications of nanotechnology in food processing industry. However, the risk issues involving the use of nanotechnology in food were also explored. The outcome of this research revealed that the nanotechnology could be useful for controlling and manipulating the matter at the nanoscale level during processing. On the other hand, nanotechnology could also help the consumers to modify the food depending on their own nutritional needs and tastes. However, from health viewpoint, the potential risks of nanoscale materials and the possibility of the accumulation and translocation of nanoparticles in the body should be avoided
Higher Dimensional Taub-NUTs and Taub-Bolts in Einstein-Maxwell Gravity
We present a class of higher dimensional solutions to Einstein-Maxwell
equations in d-dimensions. These solutions are asymptotically locally flat,
de-Sitter, or anti-de Sitter space-times. The solutions we obtained depend on
two extra parameters other than the mass and the nut charge. These two
parameters are the electric charge, q and the electric potential at infinity,
V, which has a non-trivial contribution. We Analyze the conditions one can
impose to obtain Taub-Nut or Taub-Bolt space-times, including the
four-dimensional case. We found that in the nut case these conditions coincide
with that coming from the regularity of the one-form potential at the horizon.
Furthermore, the mass parameter for the higher dimensional solutions depends on
the nut charge and the electric charge or the potential at infinity.Comment: 11 pages, LaTe
Calculation of on the Z
We perform a new, detailed calculation of the hadronic contributions to the
running electromagnetic coupling, , defined on the Z particle (91
GeV). We find for the hadronic contribution, including radiative corrections,
10^5\times \deltav_{\rm had.}\alpha(M_Z^2)= 2740\pm12, or, excluding the
top quark contribution, 10^5\times \deltav_{\rm had.}\alpha^{(5)}(M_Z^2)=
2747\pm12.
Adding the pure QED corrections we get a value for the running
electromagnetic coupling of Comment: Version to appear in Phys. Rev. D. Plain TeX fil
Gauge Theories with Time Dependent Couplings and their Cosmological Duals
We consider the N=4 SYM theory in flat 3+1 dimensional spacetime with a time
dependent coupling constant which vanishes at , like . In an
analogous quantum mechanics toy model we find that the response is singular.
The energy diverges at , for a generic state. In addition, if the
phase of the wave function has a wildly oscillating behavior, which does not
allow it to be continued past . A similar effect would make the gauge
theory singular as well, though nontrivial effects of renormalization could
tame this singularity and allow a smooth continuation beyond . The gravity
dual in some cases is known to be a time dependent cosmology which exhibits a
space-like singularity at . Our results, if applicable in the gauge theory
for the case of the vanishing coupling, imply that the singularity is a genuine
sickness and does not admit a meaningful continuation. When the coupling
remains non-zero and becomes small at , the curvature in the bulk becomes
of order the string scale. The gauge theory now admits a time evolution beyond
this point. In this case, a finite amount of energy is produced which possibly
thermalizes and leads to a black hole in the bulk.Comment: 45 pages, 1 figure; v2. minor modifications; v3: PRD version,
conclusions in the field theory case significantly revised to include
possible renormalization effects, quantum mechanics toy model unchanged,
abstract and introduction revised, additional subsection 4.1 adde
Determination of the HQET Parameters from the Decay
We combine the resummations for radiative corrections and for the heavy quark
expansion to study the inclusive radiative decay . The
infrared renormalon ambiguity is also taken into account. Including both
theoretical and experimental uncertainties, we determine the allowed domain for
the HQET parameters and centered at GeV and GeV.Comment: IR renormalon ambiguity is include
Virtual O(\a_s) corrections to the inclusive decay
We present in detail the calculation of the O(\a_s) virtual corrections to
the matrix element for b \to s \g. Besides the one-loop virtual corrections
of the electromagnetic and color dipole operators and , we include
the important two-loop contribution of the four-Fermi operator . By
applying the Mellin-Barnes representation to certain internal propagators, the
result of the two-loop diagrams is obtained analytically as an expansion in
. These results are then combined with existing O(\a_s)
Bremsstrahlung corrections in order to obtain the inclusive rate for B \to X_s
\g. The new contributions drastically reduce the large renormalization scale
dependence of the leading logarithmic result. Thus a very precise Standard
Model prediction for this inclusive process will become possible once also the
corrections to the Wilson coefficients are available.Comment: 29 pages, uses epsfig.sty, 12 postscript figures include
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