Validation of results of two different reductions for precision seamless cold drawn tubes

This paper deals with the comparison of the seamless pulling process of precision seamless tubes using two different reductions from the viewpoint of geometrical stability using computerized tomography, from the point of view of mechanical properties, from the point of view of the surface temperature in the arrangement of the tribological tube-tool pair. Validation of the pipe drawing process also took place based on the finite element method in the simulation program DEFORM 3D. From the point of view of production rationalization, it is necessary to analyze stress and deformation states at different input dimensions for a particular final dimension for a given drawing method, in this case, a drawing whiteout plug method was used

Involving users in OPAC interface design: Perspective from a UK study

This is the post-print versoin of the Article. The official published version can be accessed from the link below - Copyright @ 2007 SpringerThe purpose of this study was to determine user suggestions for a typical OPAC (Online Public Library Catalogue) application’s functionality and features. An experiment was undertaken to find out the type of interactions features that users prefer to have in an OPAC. The study revealed that regardless of users’ Information Technology (IT) backgrounds, their functionality expectations of OPACs are the same. However, based on users’ previous experiences with OPACs, their requirements with respect to specific features may change. Users should be involved early in the OPAC development cycle process in order to ensure usable and functional interface

Multi-graviton theory, a latticized dimension, and the cosmological constant

Beginning with the Pauli-Fierz theory, we construct a model for multi-graviton theory. Couplings between gravitons belonging to nearest-neighbor ``theory spaces'' lead to a discrete mass spectrum. Our model coincides with the Kaluza-Klein theory whose fifth dimension is latticized. We evaluate one-loop vacuum energy in models with a circular latticized extra dimension as well as with compact continuous dimensions. We find that the vacuum energy can take a positive value, if the dimension of the continuous space time is $6, 10,...$. Moreover, since the amount of the vacuum energy can be an arbitrary small value according to the choice of parameters in the model, our models is useful to explain the small positive dark energy in the present universe.Comment: 10 pages, No figure. Needs REVTeX4. citations are corrected and minor correction

Influence of hepatitis G virus infection on liver disease

The influence of hepatitis G virus (HGV) infection on disease activity in hepatitis C related and unrelated liver disease was investigated in 254 individuals using an EIA polymerase chain reaction assay for HGV. One hundred patients had chronic hepatitis C, 26 primary biliary cirrhosis, and 30 alcoholic liver cirrhosis. In addition, 51 hepatitis B surface antigen (HBsAg)-positive and 47 anti-hepatitis C virus (HCV)-positive blood donors were screened. Hepatitis G virus was detected in 18% of patients with chronic hepatitis C, 13% of patients with alcoholic liver cirrhosis, 11 % of patients with primary biliary cirrhosis, 10% of anti-HCV-positive blood donors, and 2% of HBsAg-positive blood donors. Virus load and alanine aminotransferase (ALT) levels did not differ significantly in patients with HCV alone versus patients coinfected with HCV and HGV. However, mild liver fibrosis correlated with HGV coinfection. Hepatitis G virus did not influence ALT levels or liver damage in liver disease unrelated to viral infectio

Simultaneous Continuation of Infinitely Many Sinks Near a Quadratic Homoclinic Tangency

We prove that the $C^3$ diffeomorphisms on surfaces, exhibiting infinitely many sinksnear the generic unfolding of a quadratic homoclinic tangency of a dissipative saddle, can be perturbed along an infinite dimensional manifold of $C^3$ diffeomorphisms such that infinitely many sinks persist simultaneously. On the other hand, if they are perturbed along one-parameter families that unfold generically the quadratic tangencies, then at most a finite number of those sinks have continuation

Key Parameters Requirements for Non‐Fullerene‐Based Organic Solar Cells with Power Conversion Efficiency >20%

The reported power conversion efficiencies (PCEs) of nonfullerene acceptor (NFA) based organic photovoltaics (OPVs) now exceed 14% and 17% for single‐junction and two‐terminal tandem cells, respectively. However, increasing the PCE further requires an improved understanding of the factors limiting the device efficiency. Here, the efficiency limits of single‐junction and two‐terminal tandem NFA‐based OPV cells are examined with the aid of a numerical device simulator that takes into account the optical properties of the active material(s), charge recombination effects, and the hole and electron mobilities in the active layer of the device. The simulations reveal that single‐junction NFA OPVs can potentially reach PCE values in excess of 18% with mobility values readily achievable in existing material systems. Furthermore, it is found that balanced electron and hole mobilities of >10−3 cm2 V−1 s−1 in combination with low nongeminate recombination rate constants of 10−12 cm3 s−1 could lead to PCE values in excess of 20% and 25% for single‐junction and two‐terminal tandem OPV cells, respectively. This analysis provides the first tangible description of the practical performance targets and useful design rules for single‐junction and tandem OPVs based on NFA materials, emphasizing the need for developing new material systems that combine these desired characteristics

Optics-less smart sensors and a possible mechanism of cutaneous vision in nature

Optics-less cutaneous (skin) vision is not rare among living organisms, though its mechanisms and capabilities have not been thoroughly investigated. This paper demonstrates, using methods from statistical parameter estimation theory and numerical simulations, that an array of bare sensors with a natural cosine-law angular sensitivity arranged on a flat or curved surface has the ability to perform imaging tasks without any optics at all. The working principle of this type of optics-less sensor and the model developed here for determining sensor performance may be used to shed light upon possible mechanisms and capabilities of cutaneous vision in nature