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Calculation Procedure (calculation + procedure)
Selected AbstractsA simple procedure to approximate slip displacement of freestanding rigid body subjected to earthquake motionsEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 4 2007Tomoyo Taniguchi Abstract A simple calculation procedure for estimating absolute maximum slip displacement of a freestanding rigid body placed on the ground or floor of linear/nonlinear multi-storey building during an earthquake is developed. The proposed procedure uses the displacement induced by the horizontal sinusoidal acceleration to approximate the absolute maximum slip displacement, i.e. the basic slip displacement. The amplitude of this horizontal sinusoidal acceleration is identical to either the peak horizontal ground acceleration or peak horizontal floor response acceleration. Its period meets the predominant period of the horizontal acceleration employed. The effects of vertical acceleration are considered to reduce the friction force monotonously. The root mean square value of the vertical acceleration at the peak horizontal acceleration is used. A mathematical solution of the basic slip displacement is presented. Employing over one hundred accelerograms, the absolute maximum slip displacements are computed and compared with the corresponding basic slip displacements. Their discrepancies are modelled by the logarithmic normal distribution regardless of the analytical conditions. The modification factor to the basic slip displacement is quantified based on the probability of the non-exceedence of a certain threshold. Therefore, the product of the modification factor and the basic slip displacement gives the design slip displacement of the body as the maximum expected value. Since the place of the body and linear/nonlinear state of building make the modification factor slightly vary, ensuring it to suit the problem is essential to secure prediction accuracy. Copyright © 2006 John Wiley & Sons, Ltd. [source] An element-wise, locally conservative Galerkin (LCG) method for solving diffusion and convection,diffusion problemsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 5 2008C. G. Thomas Abstract An element-wise locally conservative Galerkin (LCG) method is employed to solve the conservation equations of diffusion and convection,diffusion. This approach allows the system of simultaneous equations to be solved over each element. Thus, the traditional assembly of elemental contributions into a global matrix system is avoided. This simplifies the calculation procedure over the standard global (continuous) Galerkin method, in addition to explicitly establishing element-wise flux conservation. In the LCG method, elements are treated as sub-domains with weakly imposed Neumann boundary conditions. The LCG method obtains a continuous and unique nodal solution from the surrounding element contributions via averaging. It is also shown in this paper that the proposed LCG method is identical to the standard global Galerkin (GG) method, at both steady and unsteady states, for an inside node. Thus, the method, has all the advantages of the standard GG method while explicitly conserving fluxes over each element. Several problems of diffusion and convection,diffusion are solved on both structured and unstructured grids to demonstrate the accuracy and robustness of the LCG method. Both linear and quadratic elements are used in the calculations. For convection-dominated problems, Petrov,Galerkin weighting and high-order characteristic-based temporal schemes have been implemented into the LCG formulation. Copyright © 2007 John Wiley & Sons, Ltd. [source] Employment of the second-moment turbulence closure on arbitrary unstructured gridsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2004B. BasaraArticle first published online: 12 JAN 200 Abstract The paper presents a finite-volume calculation procedure using a second-moment turbulence closure. The proposed method is based on a collocated variable arrangement and especially adopted for unstructured grids consisting of ,polyhedral' calculation volumes. An inclusion of 23k in the pressure is analysed and the impact of such an approach on the employment of the constant static pressure boundary is addressed. It is shown that this approach allows a removal of a standard but cumbersome velocity,pressure ,Reynolds stress coupling procedure known as an extension of Rhie-Chow method (AIAA J. 1983; 21: 1525,1532) for the Reynolds stresses. A novel wall treatment for the Reynolds-stress equations and ,polyhedral' calculation volumes is presented. Important issues related to treatments of diffusion terms in momentum and Reynolds-stress equations are also discussed and a new approach is proposed. Special interpolation practices implemented in a deferred-correction fashion and related to all equations, are explained in detail. Computational results are compared with available experimental data for four very different applications: the flow in a two-dimensional 180o turned U-bend, the vortex shedding flow around a square cylinder, the flow around Ahmed Body and in-cylinder engine flow. Additionally, the performance of the methodology is assessed by applying it to different computational grids. For all test cases, predictions with the second-moment closure are compared to those of the k,,model. The second-moment turbulence closure always achieves closer agreement with the measurements. A moderate increase in computing time is required for the calculations with the second-moment closure. Copyright © 2004 John Wiley & Sons, Ltd. [source] A general approach for determining the diffraction contrast factor of straight-line dislocationsACTA CRYSTALLOGRAPHICA SECTION A, Issue 2 2009Jorge Martinez-Garcia Dislocations alter perfect crystalline order and produce anisotropic broadening of the X-ray diffraction profiles, which is described by the dislocation contrast factor. Owing to the lack of suitable mathematical tools to deal with dislocations in crystals of any symmetry, contrast factors are so far only known for a few slip systems in high-symmetry phases and little detail is given in the literature on the calculation procedure. In the present paper a general approach is presented for the calculation of contrast factors for any dislocation configuration and any lattice symmetry. The new procedure is illustrated with practical examples of hexagonal metals and some low-symmetry mineral phases. [source] An exergy calculator tool for process simulationASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2007Juan M. Montelongo-Luna Abstract The constant tightening of environmental regulations and the ongoing need to reduce operating costs have posed a challenge for the design of any chemical process. Process engineers use process simulators to help them perform calculations that will, ultimately, result in design parameters or operating conditions for a plant or process. Exergy is a potential indicator that can aid in the design of energy efficient chemical processes and plants. The exergy concept has been increasingly used as a tool to locate the critical energy use in many industrial processes, both chemical and non-chemical. However, currently most process simulators in the market do not offer the capability of calculating the exergy of a process. An open-source exergy calculator has been created by embedding the calculation procedure in an open-source chemical process simulator. This improves process simulation by including a potential tool for design teams to quickly evaluate several process options in detail in order to understand their energy utilisation. A simple exergy analysis for a gas processing facility is used to demonstrate the capabilities of the tool. The analysis shows where the largest quantities of exergy are being consumed within the plant, thus pointing to areas where improvement in energy usage can be made. The use of exergy as a potential design and retrofit tool is also discussed. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Die Ermittlung des Jahresnutzkühlenergiebedarfs in Bürogebäuden mit dem Berechnungsverfahren nach Energieeinsparverordnung 2007 bzw.BAUPHYSIK, Issue 2 2009DIN V 1859 Energieinsparung; Technische Regelwerke Abstract Die seit 2007 gültige Energieeinsparverordnung (EnEV) schreibt für Bürogebäude eine gesamtheitliche Bilanzierung des Energiebedarfs vor, so dass neben dem Heizwärmeverbrauch und dem Energieverbrauch für Lüftungsanlagen erstmals auch der Kühlenergieverbrauch und der Stromverbrauch für Beleuchtung zu berücksichtigen ist. Die vorliegende Studie fokussiert auf den Jahreskühlenergieverbrauch von Büroräumen, welcher neben den Rechenregeln nach EnEV 2007 bzw. DIN V 18599 auch mit Hilfe der Algorithmen in der VDI 2067 oder mittels dynamischer, thermischer Simulationen ermittelt werden kann. Hierzu wird der Jahreskühlenergiebedarf für einen typischen Büroraum mit unterschiedlichen Fassadentypen nach den verschiedenen Verfahren berechnet, um Unterschiede aufzuzeigen. Abschließend wird exemplarisch der Einfluss des dem jeweiligen Verfahren zugrundeliegenden Außenklimas aufgezeigt. Determining the annual cooling energy demand for office buildings using the calculation procedure according to the 2007 Building Energy Conservation Ordinance or the DIN V 18599 standard. The German Building Energy Conservation Ordinance (EnEV), which has been in force since 2007, requires a holistic balance of the energy demand for office buildings, so that for the first time energy used for cooling and electricity used for lighting must be taken into account besides energy used for thermal heat and ventilation systems. This study focuses on the annual energy consumption for cooling offices which can be determined not only according to the calculation rules laid down in the EnEV 2007 or DIN V 18599 standards but also with the aid of algorithms specified in VDI 2067 or by means of dynamic thermal simulations. Here the annual energy demand for cooling a typical office with different types of facade is calculated by means of various calculation procedures in order to highlight the differences and deduce which types of facade react particularly sensitively. An example is used to illustrate the influence of the prevailing outdoor weather conditions for each procedure. [source] Examples for the importance of radiophysical measurements in clinical phototherapyJOURNAL DER DEUTSCHEN DERMATOLOGISCHEN GESELLSCHAFT, Issue 5 2007Lars Alexander Schneider Summary Background: Optimal UV therapy requires regular surveillance of the variables that influence therapeutic success. In daily practice, phototherapy equipment is often operated with an attitude of "autocontrol." This implies that thorough control measurements of the emission spectra and calibration of UV fluences are not routinely performed. For both quality control and patient safety, it is essential to regularly check whether a UV source is providing the right target spectrum with the correct dose to the skin. Methods: We have exemplarily taken three UV sources currently used in clinical practice and performed radiophysical measurements, i. e. determined emission spectra, radiation output and correctness of dose calculation. Results: All three sources revealed either a largely inhomogeneous distribution pattern of radiation intensity, variation of radiation intensity over time or insufficient filtering of the UV lamp emission spectrum. Furthermore the dose calculation procedures had to be revised because of significant differences between the estimated and the administered UV doses. Conclusions: Radiophysical measurement of all UV-equipment in clinical use is a simple and effective way to improve the safety and reliability of phototherapy. Such measurements help to uncover technical flaws in radiation sources and prevent unnecessary side effects and UV exposure risks for the patient. [source] Root cadmium desorption methods and their evaluation with compartmental modelingNEW PHYTOLOGIST, Issue 1 2010Wayne T. Buckley Summary ,Desorption of plant roots is often employed in studies of plant physiology and nutrition; however, there have been few studies on the validity of desorption procedures. ,Branched and in-line kinetic models with five compartments , cadmium (Cd)-chelate, Cd2+, root apoplast, root symplast and vacuole , were developed to evaluate the efficacy of diethylenetriaminepentaacetic acid (DTPA) and CaCl2 methods for the desorption of Cd from roots of durum wheat seedlings. Solution Cd2+ could exchange with apoplast and symplast Cd simultaneously in the branched model and sequentially in the in-line model. ,A 10-min desorption with 1 × 10,6 M DTPA at room temperature or cold (0°C) 5 × 10,3 M CaCl2 was required to achieve 99% recovery of apoplast-bound 109Cd when experimental results were interpreted with the branched model. However, when the same data sets were analysed with the in-line model, only partial desorption was achieved. Arguments are presented that suggest that the branched model is correct. ,It is suggested that compartmental modeling is a suitable tool for the study of plant root uptake and desorption kinetics, and that there are advantages over more commonly used calculation procedures. [source] Die Ermittlung des Jahresnutzkühlenergiebedarfs in Bürogebäuden mit dem Berechnungsverfahren nach Energieeinsparverordnung 2007 bzw.BAUPHYSIK, Issue 2 2009DIN V 1859 Energieinsparung; Technische Regelwerke Abstract Die seit 2007 gültige Energieeinsparverordnung (EnEV) schreibt für Bürogebäude eine gesamtheitliche Bilanzierung des Energiebedarfs vor, so dass neben dem Heizwärmeverbrauch und dem Energieverbrauch für Lüftungsanlagen erstmals auch der Kühlenergieverbrauch und der Stromverbrauch für Beleuchtung zu berücksichtigen ist. Die vorliegende Studie fokussiert auf den Jahreskühlenergieverbrauch von Büroräumen, welcher neben den Rechenregeln nach EnEV 2007 bzw. DIN V 18599 auch mit Hilfe der Algorithmen in der VDI 2067 oder mittels dynamischer, thermischer Simulationen ermittelt werden kann. Hierzu wird der Jahreskühlenergiebedarf für einen typischen Büroraum mit unterschiedlichen Fassadentypen nach den verschiedenen Verfahren berechnet, um Unterschiede aufzuzeigen. Abschließend wird exemplarisch der Einfluss des dem jeweiligen Verfahren zugrundeliegenden Außenklimas aufgezeigt. Determining the annual cooling energy demand for office buildings using the calculation procedure according to the 2007 Building Energy Conservation Ordinance or the DIN V 18599 standard. The German Building Energy Conservation Ordinance (EnEV), which has been in force since 2007, requires a holistic balance of the energy demand for office buildings, so that for the first time energy used for cooling and electricity used for lighting must be taken into account besides energy used for thermal heat and ventilation systems. This study focuses on the annual energy consumption for cooling offices which can be determined not only according to the calculation rules laid down in the EnEV 2007 or DIN V 18599 standards but also with the aid of algorithms specified in VDI 2067 or by means of dynamic thermal simulations. Here the annual energy demand for cooling a typical office with different types of facade is calculated by means of various calculation procedures in order to highlight the differences and deduce which types of facade react particularly sensitively. An example is used to illustrate the influence of the prevailing outdoor weather conditions for each procedure. [source] | |||||||||||||