444 research outputs found
Investigation on the Influence of Basalt Fiber on Thermal properties of Al7075/ Basalt Fiber Metal Matrix Composites.
This paper reports a study of the Coefficient of Thermal Expansion (CTE) of Al7075/basalt short fiber Metal Matrix Composites (MMCs) as a function of temperature and reinforcement. The percentage of reinforcement was varied from 2.5 to 10 wt. % in steps of 2.5% and the composites were prepared by the liquid metallurgy technique. Using Thermal Mechanical Analyzer (TMA) model DuPont 943 equipment, the changes in the linear dimension as a function of temperature is recorded as Percent Linear Change (PLC). The temperature of the tests ranged from 50 °C to 300 °C in the steps of 5 °C both in the heating and cooling cycles. The results show that the CTE significantly increased with increasing temperature but decreased with increasing basalt fiber. These phenomena are explained
Analisis Kinerja Kualitas Jasa Pelayanan dan Kepuasan Pelanggan pada PT. Pln (Persero) Cabang Manokwari (Studi Kasus Pelanggan Rumah Tangga pada Area Manokwari Kota)
This study aims to investigate the performance of service quality and customer satisfaction household PT. PLN ( Persero ) Branch Manokwari Manokwari City area , as well as to know what are the things that need to be repaired and maintained in order to improve customer satisfaction PT . PLN ( Persero ) Branch Manokwari . The population used in this study is household’s customers in the city of Manokwari amounts to 21,899 customers. While the sample used in this research were 100 respondents, with a sample calculation using the formula Slovin and sampling techniques using Convenience Sampling. This type of research is descriptive quantitative data analysis. Data analysis tool in this study used SPSS (Statistical Package for the Social Science) to test validity and reliability test of the questionnaires, and the use of Cartesian diagram. The results showed that the average value of customer perceived performance ie PLN 3.40 less than the average value of the customers' expectations of 4.24, meaning that the databases must address satisfying customer satisfaction PLN is still perceived to be at lower levels are still below standard or customer expectations . In addition , as for the things that need to be fixed by the PLN ( located in quadrant A), is dominated by a factor of dimension responsiveness and things that need to be maintained by the PLN (located in quadrant B), namely : a factor of dimensions of empathy ( the payment deadline notification electricity ) and tangible dimensions ( appeals to the public ( customers ) related to the use of electricity ) . While on the other quadrant (quadrant C and D quadrant) is proposed as a form of recommendation of the author to the PT. PLN (Persero)
Measuring the proton spectrum in neutron decay - latest results with aSPECT
The retardation spectrometer aSPECT was built to measure the shape of the
proton spectrum in free neutron decay with high precision. This allows us to
determine the antineutrino electron angular correlation coefficient a. We aim
for a precision more than one order of magnitude better than the present best
value, which is Delta_a /a = 5%.
In a recent beam time performed at the Institut Laue-Langevin during April /
May 2008 we reached a statistical accuracy of about 2% per 24 hours measurement
time. Several systematic effects were investigated experimentally. We expect
the total relative uncertainty to be well below 5%.Comment: Accepted for publication in the Conference Proceedings of the
International Workshop on Particle Physics with Slow Neutrons 2008 held at
the ILL, France. To be published in Nuclear Instruments and Methods in
Physics Research, Section
A homological interpretation of the transverse quiver Grassmannians
In recent articles, the investigation of atomic bases in cluster algebras
associated to affine quivers led the second-named author to introduce a variety
called transverse quiver Grassmannian and the first-named and third-named
authors to consider the smooth loci of quiver Grassmannians. In this paper, we
prove that, for any affine quiver Q, the transverse quiver Grassmannian of an
indecomposable representation M is the set of points N in the quiver
Grassmannian of M such that Ext^1(N,M/N)=0. As a corollary we prove that the
transverse quiver Grassmannian coincides with the smooth locus of the
irreducible components of minimal dimension in the quiver Grassmannian.Comment: final version, 7 pages, corollary 1.2 has been modifie
Rupture of multiple parallel molecular bonds under dynamic loading
Biological adhesion often involves several pairs of specific receptor-ligand
molecules. Using rate equations, we study theoretically the rupture of such
multiple parallel bonds under dynamic loading assisted by thermal activation.
For a simple generic type of cooperativity, both the rupture time and force
exhibit several different scaling regimes. The dependence of the rupture force
on the number of bonds is predicted to be either linear, like a square root or
logarithmic.Comment: 8 pages, 2 figure
Categorical Tinkertoys for N=2 Gauge Theories
In view of classification of the quiver 4d N=2 supersymmetric gauge theories,
we discuss the characterization of the quivers with superpotential (Q,W)
associated to a N=2 QFT which, in some corner of its parameter space, looks
like a gauge theory with gauge group G. The basic idea is that the Abelian
category rep(Q,W) of (finite-dimensional) representations of the Jacobian
algebra should enjoy what we call the Ringel
property of type G; in particular, rep(Q,W) should contain a universal
`generic' subcategory, which depends only on the gauge group G, capturing the
universality of the gauge sector. There is a family of 'light' subcategories
, indexed by points , where
is a projective variety whose irreducible components are copies of
in one--to--one correspondence with the simple factors of G.
In particular, for a Gaiotto theory there is one such family of
subcategories, , for each maximal degeneration of
the corresponding surface , and the index variety may be identified
with the degenerate Gaiotto surface itself: generic light subcategories
correspond to cylinders, while closed-point subcategories to `fixtures'
(spheres with three punctures of various kinds) and higher-order
generalizations. The rules for `gluing' categories are more general that the
geometric gluing of surfaces, allowing for a few additional exceptional N=2
theories which are not of the Gaiotto class.Comment: 142 pages, 8 figures, 5 table
On Arnold's 14 `exceptional' N=2 superconformal gauge theories
We study the four-dimensional superconformal N=2 gauge theories engineered by
the Type IIB superstring on Arnold's 14 exceptional unimodal singularities
(a.k.a. Arnold's strange duality list), thus extending the methods of 1006.3435
to singularities which are not the direct sum of minimal ones. In particular,
we compute their BPS spectra in several `strongly coupled' chambers.
From the TBA side, we construct ten new periodic Y-systems, providing
additional evidence for the existence of a periodic Y-system for each isolated
quasi-homogeneous singularity with (more generally, for each N=2
superconformal theory with a finite BPS chamber whose chiral primaries have
dimensions of the form N/l).Comment: 73 pages, 7 figure
Elastic deformation of a fluid membrane upon colloid binding
When a colloidal particle adheres to a fluid membrane, it induces elastic
deformations in the membrane which oppose its own binding. The structural and
energetic aspects of this balance are theoretically studied within the
framework of a Helfrich Hamiltonian. Based on the full nonlinear shape
equations for the membrane profile, a line of continuous binding transitions
and a second line of discontinuous envelopment transitions are found, which
meet at an unusual triple point. The regime of low tension is studied
analytically using a small gradient expansion, while in the limit of large
tension scaling arguments are derived which quantify the asymptotic behavior of
phase boundary, degree of wrapping, and energy barrier. The maturation of
animal viruses by budding is discussed as a biological example of such
colloid-membrane interaction events.Comment: 14 pages, 9 figures, REVTeX style, follow-up on cond-mat/021242
'The nourishing soil of the soul': The role of horticultural therapy in promoting well-being in community-dwelling people with dementia.
Two-thirds of people with dementia reside in their own homes; however, support for community-dwelling people with dementia to continue to participate in everyday activities is often lacking, resulting in feelings of depression and isolation among people living with the condition. Engagement in outdoor activities such as gardening can potentially counteract these negative experiences by enabling people with dementia to interact with nature, helping to improve their physical and psychological well-being. Additionally, the collaborative nature of community gardening may encourage the development of a sense of community, thereby enhancing social integration. Despite increasing evidence supporting its therapeutic value for people with dementia in residential care, the benefits of horticultural therapy have yet to be transposed into a community setting. This paper will examine the theoretical support for the application of horticultural therapy in dementia care, before exploring the potential of horticultural therapy as a means of facilitating improved physical and psychological well-being and social integration for people living with dementia within the community
Gorenstein homological algebra and universal coefficient theorems
We study criteria for a ring—or more generally, for a small category—to be Gorenstein and for a module over it to be of finite projective dimension. The goal is to unify the universal coefficient theorems found in the literature and to develop machinery for proving new ones. Among the universal coefficient theorems covered by our methods we find, besides all the classic examples, several exotic examples arising from the KK-theory of C*-algebras and also Neeman’s Brown–Adams representability theorem for compactly generated categories
- …