The paper presents preliminary results of an experimental study on solar water heater with full width and 75% twisted tapes as heat transfer enhancement device. The study shows that the thermal efficiency due the use of the twisted tape increases by 4.5-8%; higher for the 75% twisted tape. Keyword Solar water heater (collector), tube-in-fin, twisted tape, thermal efficiency, performance enhance...

Adresa za dopisivanje Prof. Dr. Carlos Menezes Aguiar, Rua Aristides Muniz, 70/501, Boa Viagem, Recife PE 51020-150 Brazil. Tel: (+55) 81 3467 6821. [email protected] Sažetak Svrha: Korištenjem konične kompjutorizirane tomografije (CBCT-a) željela se odrediti mogućnost centriranja Twisted Fileom u usporedbi sa strojnim sustavom Revo-S. Materijali i metode: Četrdeset bukomezijalnih kana...

Chen and Ruan [6] defined a very interesting cohomology theory-Chen-Ruan orbifold cohomology. The primary objective of this paper is to compute the Chen-Ruan orbifold cohomology of weighted projective space, one of the most important space used in physics. The classical tools (orbifold cohomology defined by Chen and Ruan,toric varieties, the localization formula) which have been proved to be su...

Let L = 1∪· · ·∪ d+1 be an oriented link in S3, and let L(q) be the d-component link 1 ∪· · ·∪ d regarded in the homology 3-sphere that results from performing 1/q-surgery on d+1. Results about the Alexander polynomial and twisted Alexander polynomials of L(q) corresponding to finite-image representations are obtained. The behavior of the invariants as q increases without bound is described.

By screening all the ligand binding sites in the Protein Data Bank, we have found that while it is geometrically possible that a loop, formed from a protein chain with residues ZYX, would "impersonate" another chain-loop with residues XYZ by a simple twisting of either the loop or the bound ligand, it almost never happens. This fact is rather surprising, and implies a notable asymmetry, since (...

Author Contact: David Giles, Dept. of Economics, University of Victoria, P.O. Box 1700, STN CSC, Victoria, B.C., Canada V8W 2Y2; e-mail: [email protected]; FAX: (250) 721-6214 Abstract We consider the seasonal distribution of turning points in the post-war growth cycles of sixteen economies. Using nonparametric tests for distributions on the circle, we cannot reject the hypothesis of a uniform dis...

Motivated by string theory on the orbifold M/G in presence of a Kalb-Ramond field strength H , we define the operators that lift the group action to the twisted sectors. These operators turn out to generate the quasi-quantum group Dω[G], introduced in the context of conformal field theory by R. Dijkgraaf, V. Pasquier and P. Roche [1], with ω a 3-cocycle determined by a series of cohomological e...

Twisted curves in R' are those which have independent derivatives up to order m . For plane and spatial curves the twisted condition is equivalent to never vanishing curvature and torsion respectively. We give a necessary and sufficient condition for a (q, p)-curve on a torus to be twisted, and use those curves to construct closed twisted curves in R'" for all m .

We study the mutual consistency of twisted boundary conditions in the coset conformal field theory G/H. We calculate the overlap of the twisted boundary states of G/H with the untwisted ones, and show that the twisted boundary states are consistently defined in the diagonal modular invariant. The overlap of the twisted boundary states is expressed by the branching functions of a twisted affine ...

Recently, Cangul et al. [I.N. Cangul, H. Ozden and Y. Simsek, Generating functions of the (h, q) extension of twisted Euler polynomials and numbers, Acta Math. Hungar. 120(3) (2008), 281-299] constructed new generating functions of the twisted (h, q)-Euler numbers and polynomials attached to a Dirichlet character χ. They also constructed the partially twisted (h, q)-zeta function. They suggeste...