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131.
Performance Capacity of Concrete containing Fly Ash The conception to take into account the addition of fly ash to structural concrete presented in the German Standard DIN 1045‐2 should guarantee a high resistance of concrete structures against corrosive attack. In this context, criteria such as compressive and flexural strength of concrete, modulus of elasticity, bond strength, shrinkage and creep as well as the pore structure are focused in this paper. The obtained results on concretes containing a maximum of fly ash according to DIN 1045‐2 compared with concretes produced only with ordinary Portland cement show similar strength values at the age of 28 days while the strength development is somewhat lower for the fly ash concretes. However, at the age of one year the strength of fly ash concretes in particular also the flexural strength is considerably higher. Shrinkage and creep of the fly ash concrete is lower resulting in an overall reduced risk of shrinkage and thermal cracking. 相似文献
132.
Micro-slip is a phenomenon that occurs between contacting surfaces when a frictional load, less than that necessary to produce macro-slip, is applied to the contacting surfaces. A model is evaluated for micro-slip between a flat smooth surface and a flat rough surface. The rough surface is covered with uniformly distributed ellipsoidal elastic asperities. The results from simulations of the model show that anisotropy, material combination and number of contacts of the contacting surfaces influence the tangential stiffness at zero displacement, the length of the micro-slip zone and the energy dissipated in the contact. An experimental investigation verifies the results computed by the model. 相似文献
133.
Luis G. Nardin Giulia Andrighetto Rosaria Conte Áron Székely David Anzola Corinna Elsenbroich Ulf Lotzmann Martin Neumann Valentina Punzo Klaus G. Troitzsch 《Autonomous Agents and Multi-Agent Systems》2016,30(6):1117-1147
Protection racketeering groups are powerful, deeply entrenched in multiple societies across the globe, and they harm the societies and economies in which they operate in multiple ways. These reasons make their dynamics important to understand and an objective of both scientific and application-oriented interest. Legal and social norm-based approaches arguably play significant roles in influencing protection racket dynamics. We propose an agent-based simulation model, the Palermo Scenario, to enrich our understanding of these influences and to test the effect of different policies on protection racket dynamics. Our model integrates the legal and the social norm-based approaches and uses a complex normative agent architecture that enables the analysis of both agents’ behaviours and mental normative representations driving behaviour. We demonstrate the usefulness of the model and the benefits of using this complex normative architecture through a case study of the Sicilian Mafia. 相似文献
134.
Pierangelo Dell'Acqua Ulf Nilsson Luís Moniz Pereira 《Electronic Notes in Theoretical Computer Science》2002,70(5)
We present a logic programming based asynchronous multi-agent system in which agents can communicate with one another; update themselves and each other; abduce hypotheses to explain observations, and use them to generate actions. The knowledge base of the agents is comprised of generalized logic programs, integrity constraints, active rules, and of abducibles. We characterize the interaction among agents via an asynchronous transition rule system, and provide a stable models based semantics. An example is developed to illustrate how our approach works. 相似文献
135.
Mathematical modelling has proven to be very useful in process design, operation and optimisation. A recent trend in WWTP modelling is to include the different subunits in so-called plant-wide models rather than focusing on parts of the entire process. One example of a typical plant-wide model is the coupling of an upstream activated sludge plant (including primary settler, and secondary clarifier) to an anaerobic digester for sludge digestion. One of the key challenges when coupling these processes has been the definition of an interface between the well accepted activated sludge model (ASM1) and anaerobic digestion model (ADM1). Current characterisation and interface models have key limitations, the most critical of which is the over-use of Xc (or lumped complex) variable as a main input to the ADM1. Over-use of Xc does not allow for variation of degradability, carbon oxidation state or nitrogen content. In addition, achieving a target influent pH through the proper definition of the ionic system can be difficult. In this paper, we define an interface and characterisation model that maps degradable components directly to carbohydrates, proteins and lipids (and their soluble analogues), as well as organic acids, rather than using Xc. While this interface has been designed for use with the Benchmark Simulation Model No. 2 (BSM2), it is widely applicable to ADM1 input characterisation in general. We have demonstrated the model both hypothetically (BSM2), and practically on a full-scale anaerobic digester treating sewage sludge. 相似文献
136.
Priscila Benar Adilson R. Gonçalves Dalmo Mandelli Márcia M. C. Ferreira Ulf Schuchardt 《木材化学与工艺学杂志》2013,33(1-2):151-165
Abstract The hydroxymethylation of Acetosolv lignin from sugarcane bagasse was studied at 40°C between 0.25 and 8 h by Fourier-transformed infrared spectroscopy (FTIR). Principal Component Analysis (PCA) of the spectra has determined that addition of formaldehyde to the lignin fragments was completed within 4 h. After that time, only condensation of the fragments occurs, leading to a resol-type crosslinked resin. PCA performed in selected regions of the FTIR spectra showed that the same results are also obtained for the stretching region of O-H and C-H within the range from 2800 to 3800 cm?1, which is not usually considered in the spectroscopic evaluations of modified lignins. 相似文献
137.
138.
This paper describes and validates by comparisons with tests a one‐zone model for computing temperature of fully developed compartment fires. Like other similar models, the model is based on an analysis of the energy and mass balance assuming combustion being limited by the availability of oxygen, ie, a ventilation‐controlled compartment fire. However, the mathematical solution techniques in this model have been altered. To this end, a maximum fire temperature has been defined depending on combustion efficiency and opening heights only. This temperature together with well‐defined fire compartment parameters was then used as a fictitious thermal boundary condition of the surrounding structure. The temperature of that structure could then be calculated with various numerical and analytical methods as a matter of choice, and the fire temperature could be identified as a weighted average between the maximum fire temperature and the calculated surface temperature of the surrounding structure as a function of time. It is demonstrated that the model can be used to predict fire temperatures in compartments with boundaries of semi‐infinitely thick structures as well as with boundaries of insulated and noninsulated steel sheets where the entire heat capacity of the surrounding structure is assumed to be concentrated to the steel core. With these assumptions, fire temperatures could be calculated with spreadsheet calculation methods. For more advanced problems, a general finite element solid temperature calculation code was used to calculate the temperature in the boundary structure. With this code, it is possible to analyze surrounding structures of various kinds, for example, structures comprising several materials with properties varying with temperature as well as voids. The validation experiments were accurately defined and surveyed. In all the tests, a propane diffusion burner was used as the only fire source. Temperatures were measured with thermocouples and plate thermometers at several positions. 相似文献
139.
Genome-Wide Investigation of Multifocal and Unifocal Prostate Cancer—Are They Genetically Different?
Chinyere Ibeawuchi Hartmut Schmidt Reinhard Voss Ulf Titze Mahmoud Abbas Joerg Neumann Elke Eltze Agnes Marije Hoogland Guido Jenster Burkhard Brandt Axel Semjonow 《International journal of molecular sciences》2013,14(6):11816-11829
Prostate cancer is widely observed to be biologically heterogeneous. Its heterogeneity is manifested histologically as multifocal prostate cancer, which is observed more frequently than unifocal prostate cancer. The clinical and prognostic significance of either focal cancer type is not fully established. To investigate prostate cancer heterogeneity, the genetic profiles of multifocal and unifocal prostate cancers were compared. Here, we report observations deduced from tumor-tumor comparison of copy number alteration data of both focal categories. Forty-one fresh frozen prostate cancer foci from 14 multifocal prostate cancers and eight unifocal prostate cancers were subjected to copy number variation analysis with the Affymetrix SNP 6.0 microarray tool. With the investigated cases, tumors obtained from a single prostate exhibited different genetic profiles of variable degrees. Further comparison identified no distinct genetic pattern or signatures specific to multifocal or unifocal prostate cancer. Our findings suggest that samples obtained from multiple sites of a single unifocal prostate cancer show as much genetic heterogeneity and variability as separate tumors obtained from a single multifocal prostate cancer. 相似文献
140.