Search results for " Simulation"
showing 10 items of 4034 documents
An efficient framework for the elasto-plastic reliability assessment of uncertain wind excited systems
2016
Abstract In this paper a method to efficiently evaluate the reliability of elastic-perfectly plastic structures is proposed. The method is based on combining dynamic shakedown theory with Subset Simulation. In particular, focus is on describing the shakedown behavior of uncertain elasto-plastic systems driven by stochastic wind loads. The ability of the structure to shakedown is assumed as a limit state separating plastic collapse from a safe, if not elastic, state of the structure. The limit state is therefore evaluated in terms of a probabilistic load multiplier estimated through solving a series of linear programming problems posed in terms of the responses of the underlying linear elast…
Hypoxia-Selective Dissociation Mechanism of a Nitroimidazole Nucleoside in a DNA Environment
2019
Photodynamic therapy is a promising approach to treat a variety of superficial tumors and other diseases. One of its major limitations arises from its dependence on molecular oxygen, which decreases the efficiency of the therapy in hypoxia conditions commonly developed by solid tumors. The present contribution reveals the molecular mechanism of a modified thymine bearing a nitroimidazole substituent, a photosensitizer able to produce highly harmful interstrand cross-links in the DNA double strand after irradiation selectively in absence of oxygen. The mechanism is resolved at a fully atomistic and electronic level relying on quantum mechanics (CASPT2, coupled-cluster, DFT, and TD-DFT method…
A comparative study of carboxy myoglobin in saccharide-water systems by molecular dynamics simulation.
2007
Results from room-temperature molecular dynamics simulation on a system containing carboxy-myoglobin, water, and maltose molecules are reported. Protein atomic fluctuations, protein−solvent and solvent−solvent hydrogen bonding have been analyzed and compared to the ones in trehalose−water and sucrose−water systems (Proteins 2005, 59, 291−302). Results help in rationalizing, at a molecular level, the effects of homologues disaccharides on protein structure/dynamics experimentally observed. Furthermore, the effectiveness of disaccharides in bioprotection in terms of peculiar protein−matrix coupling is also discussed.
Volume change behaviour of a compacted scaly clay during cyclic suction changes
2010
The research presented in this paper focuses on the investigation and modelling of the volume change response of compacted tectonised clay samples subjected to several wetting and drying cycles in controlled-suction oedometers. Oedometer tests were carried out under different values of constant vertical net stress, and wetting and drying cycles were performed varying applied matric suction between 10 and 800 kPa. The investigation was complemented with a study of the material microstructure to support the interpretation of the overall mechanical response. At a microscopic level, the material is characterized by different types of particle assemblages, scales, and clay aggregates. One of th…
Dynamic daylight simulations: Impact of weather file’s choice
2015
Abstract This paper is the second step of a research project aimed at investigating the impact of the use of different weather data files on daylight simulations’ results. Simulations were carried out for a simple standalone office using three weather files (IWEC, Meteonorm and Satel-Light) for two European locations (Copenhagen and Rome); moreover the office’s exposure was changed according to the four main orientations (North, East, South and West). Results were analyzed both in terms of Annual and Monthly Light Exposures, dynamic daylight performance metrics (DA, DAcon, UDI) and sunlight’s incidence. It was demonstrated that differences between the results obtained with the different wea…
ANALYSIS OF SUNSPOT NUMBER FLUCTUATIONS
2004
Monthly averages of the sunspot number visible on the sun, observed from 1749, Zurich Observatory, and from 1848 other observatories, have been analyzed. This time signal presents a frequency power spectra with a clear 1/fα behavior with α≃0.8±0.2. The well-known cycle of approximately 11 years, clearly present in the spectrum, does not produce a sensible distortion of that behavior. The eventual characterization of the sunspot time series as a fractal is analyzed by means of the detrended fluctuation analysis (DFA). The jump-size distribution of the signal is also studied.
A fuel cell-based hybrid power supply for portable electronics devices
2008
A fuel cell - supercapacitor hybrid power supply for portable applications is designed. To ensure system level simulation, each component is accurately modeled and simulation results are reported. A Digital Still Camera is selected as specific load device, although the choice of a specific application does not influence the proposed control technique performances but only dictates the power supply specifications. The fuel cell and the power management system are modeled in PSIM. © 2008 IEEE.
Spectral broadening by spatial effects in X-ray microcalorimeters with superconducting absorber and NTD-Ge thermal sensor
2004
We discuss how the sensitivity to the position of absorption of the photons can affect the spectral resolution of X-ray microcalorimeters with superconducting Sn absorber and NTD-Ge thermal sensor. Data obtained through the computer simulations are reported for microcalorimeters with different geometries and phonon transmission probabilities at the interface between the absorber and thermistor.
Capacity constrained supply chains: a simulation study
2008
This paper explores the relationship between constrained capacity and supply chain performance. Six capacity constraint levels are studied under different inventory policies and information sharing strategies. The results suggest that an increment of production capacity, used in industry as local approach to manage increasing incoming orders, does not necessarily imply an improvement in customer service. In presence of information distortions, the strategy of augmenting production capacity can lead to satisfy at a higher cost an over-estimated market demand. The collaborative practices provide bullwhip effect dampening and inventory stability, and increase the ability of the structure to av…
Up-to-Date Supply Chain Management: The Coordinated (S, R) Order-Up-to
2011
This paper presents the mathematical derivation of a new generation of the most largely used periodic review policy in supply chain: the coordinated (S, R) replenishment rule. We first derive the classical order-up-to model and then we modify it to generate the coordinated decision policy equations. We run a numerical simulation on a serial supply chain model to show differences in the two policies. We conclude on the managerial implications related to coordinated replenishment.