1,197 research outputs found

    Automatic Generation of Matrix Element Derivatives for Tight Binding Models

    Full text link
    Tight binding (TB) models are one approach to the quantum mechanical many particle problem. An important role in TB models is played by hopping and overlap matrix elements between the orbitals on two atoms, which of course depend on the relative positions of the atoms involved. This dependence can be expressed with the help of Slater-Koster parameters, which are usually taken from tables. Recently, a way to generate these tables automatically was published. If TB approaches are applied to simulations of the dynamics of a system, also derivatives of matrix elements can appear. In this work we give general expressions for first and second derivatives of such matrix elements. Implemented in a computer program they obviate the need to type all the required derivatives of all occuring matrix elements by hand.Comment: 11 pages, 2 figure

    Aplikasi Model Optimasi Untuk Meningkatkan Efisiensi Pengangkutan Sampah Di Kota Cilegon

    Get PDF
    Most cities in developing countries face inefficiency problem of waste collection service run by government. The purpose of this study is to estimate the efficiency of waste collection service and the capital cost requirement in 2019 to cover 100% waste collection service in Cilegon City. The efficiency is calculated by comparing the current costs with the optimization costs by the model of vehicle routing problem. The result shows that the obtained inefficiency reaches 37,48% which largely comes from the labor component. To cover all of resident in Cilegon City, the city needs to increase their budget allocation as much as IDR 33,884 billion in 2019

    Media Penunjang Informasi dan Promosi Berbentuk Katalog Produk pada PT. Ideal Formica Purnatata Tangerang

    Full text link
    Visual communications media plays an important role in the self-introduction a company primarily in supporting information and promotion. One of the visual communication media is very important in supporting the successful sale of the company is a media product catalog. Companies in need of information and promotional media such as print media, because the media is effective compared with other media such as video profile. PT. Ideal Formica Purnatata is a company engaged in the manufacture of products and architectural interiors. The purpose of this study, so that the company can achieve its sales target of each product marketed. To obtain accurate data in the preparation of the study, there is the research methodology used are: problem analysis methods, data collection methods, methods of design analysis and methods of design concepts. The problem that exists is the lack of information and promotional media such as media product catalog. Visual communication media has a method of designing one form of material used is 260 g carton art and art paper 120 gr. The choice of material is in use because of the materials according to the media catalog. Media design through product catalogs, is expected to increase the attractiveness of the consumer to use the services and products of PT. Ideal Formica Purnatata, so that the sales target is reached, the company\u27s turnover increased, and PT. Ideal Formica Purnatata widely known

    Strings on type IIB pp-wave backgrounds with interacting massive theories on the worldsheet

    Full text link
    We consider superstring theories on pp-wave backgrounds which result in an integrable N=(2,2){\cal N}=(2,2) supersymmetric Landau-Ginzburg theory on the worldsheet. We obtain exact eigenvalues of the light-cone gauge superstring hamiltonian in the massive and interacting world-sheet theory with superpotential Z3ZZ^3-Z. We find the modes of the supergravity part of the string spectrum, and their space-time interpretation. Because the system is effectively at strong coupling on the worldsheet, these modes are not in one-to-one correspondence with the usual type IIB supergravity modes in the p0p_{-} \to 0 limit. However, the above correspondence holds in the α0\alpha'\to 0 limit.Comment: 20 pages, 1 figure; minor changes, comments adde

    Summer CO2 evasion from streams and rivers in the Kolyma River basin, north-east Siberia

    Get PDF
    Inland water systems are generally supersaturated in carbon dioxide (CO2) and are increasingly recognized as playing an important role in the global carbon cycle. The Arctic may be particularly important in this respect, given the abundance of inland waters and carbon contained in Arctic soils; however, a lack of trace gas measurements from small streams in the Arctic currently limits this understanding.We investigated the spatial variability of CO2 evasion during the summer low-flow period from streams and rivers in the northern portion of the Kolyma River basin in north-eastern Siberia. To this end, partial pressure of carbon dioxide (pCO2) and gas exchange velocities (k) were measured at a diverse set of streams and rivers to calculate CO2 evasion fluxes. We combined these CO2 evasion estimates with satellite remote sensing and geographic information system techniques to calculate total areal CO2 emissions. Our results show that small streams are substantial sources of atmospheric CO2 owing to high pCO2 and k, despite being a small portion of total inland water surface area. In contrast, large rivers were generally near equilibrium with atmospheric CO2. Extrapolating our findings across the Panteleikha-Ambolikha sub-watersheds demonstrated that small streams play a major role in CO2 evasion, accounting for 86% of the total summer CO2 emissions from inland waters within these two sub-watersheds. Further expansion of these regional CO2 emission estimates across time and space will be critical to accurately quantify and understand the role of Arctic streams and rivers in the global carbon budget

    The u'g'r'i'z' Standard Star Network

    Full text link
    We present the 158 standard stars that define the u'g'r'i'z' photometric system. These stars form the basis for the photometric calibration of the Sloan Digital Sky Survey (SDSS). The defining instrument system and filters, the observing process, the reduction techniques, and the software used to create the stellar network are all described. We briefly discuss the history of the star selection process, the derivation of a set of transformation equations for the UBVRcIc system, and plans for future work.Comment: References to URLs in paper have been updated to reflect moved website. Accepted by AJ. 50 pages, including 20 pages of text, 9 tables, and 15 figures. Plain ASCII text versions of Tables 8 and 9 can be found at http://home.fnal.gov/~dtucker/ugriz/index.html (new URL

    Two-loop world-sheet corrections in AdS_5 x S^5 superstring

    Full text link
    We initiate the computation of the 2-loop quantum AdS_5 x S^5 string corrections on the example of a certain string configuration in S^5 related by an analytic continuation to a folded rotating string in AdS_5 in the ``long string'' limit. The 2-loop term in the energy of the latter should represent the subleading strong-coupling correction to the cusp anomalous dimension and thus provide a further check of recent conjectures about the exact structure of the Bethe ansatz underlying the AdS/CFT duality. We use the conformal gauge and several choices of the \kappa-symmetry gauge. While we are unable to verify the cancellation of 2d UV divergences we compute the bosonic contribution to the effective action and also determine the non-trivial finite part of the fermionic contribution. Both the bosonic and the fermionic contributions to the string energy happen to be proportional to the Catalan's constant. The resulting value for 2-loop superstring prediction for the subleading coefficient a_2 in the scaling function matches the numerical value found in hep-th/0611135 from the BES equation.Comment: 48 pages, 1 Figure. v3: several mistakes corrected, the finite result for the 2-loop coefficient is found to agree with the numerical value found by Benna et al in hep-th/061113
    corecore