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排序方式: 共有151条查询结果,搜索用时 15 毫秒
31.
Marcela Monroy‐Licht Ciro Alberto Amaya André Langevin Louis‐Martin Rousseau 《International Transactions in Operational Research》2017,24(6):1325-1346
In this paper, the rescheduling arc routing problem is introduced. This is a dynamic routing and scheduling problem that considers adjustments to an initial routing itinerary when one or more vehicle failures occur during the execution stage and the original plan must be modified. We minimize the operational and schedule disruption costs. Formulations based on mixed‐integer programming are presented to compare different policies in the rerouting phase. A solution strategy is developed when both costs are evaluated and it is necessary to find a solution quickly. Computational tests on a large set of instances compare the different decision‐maker policies. 相似文献
32.
Paola Sini Thi Bang Chau Dang Milena Fais Manuela Galioto Bachisio Mario Padedda Antonella Lugli Ciro Iaccarino Claudia Crosio 《International journal of molecular sciences》2021,22(16)
The prevalence of neurodegenerative disease (ND) is increasing, partly owing to extensions in lifespan, with a larger percentage of members living to an older age, but the ND aetiology and pathogenesis are not fully understood, and effective treatments are still lacking. Neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis are generally thought to progress as a consequence of genetic susceptibility and environmental influences. Up to now, several environmental triggers have been associated with NDs, and recent studies suggest that some cyanotoxins, produced by cyanobacteria and acting through a variety of molecular mechanisms, are highly neurotoxic, although their roles in neuropathy and particularly in NDs are still controversial. In this review, we summarize the most relevant and recent evidence that points at cyanotoxins as environmental triggers in NDs development. 相似文献
33.
Considerable research has been carried out into open roads to establish relationships between crashes and traffic flow, geometry of infrastructure and environmental factors, whereas crash-prediction models for road tunnels, have rarely been investigated. In addition different results have been sometimes obtained regarding the effects of traffic and geometry on crashes in road tunnels. However, most research has focused on tunnels where traffic and geometric conditions, as well as driving behaviour, differ from those in Italy. Thus, in this paper crash prediction-models that had not yet been proposed for Italian road tunnels have been developed. For the purpose, a 4-year monitoring period extending from 2006 to 2009 was considered. The tunnels investigated are single-tube ones with unidirectional traffic. The Bivariate Negative Binomial regression model, jointly applied to non-severe crashes (accidents involving material-damage only) and severe crashes (fatal and injury accidents only), was used to model the frequency of accident occurrence. The year effect on severe crashes was also analyzed by the Random Effects Binomial regression model and the Negative Multinomial regression model. Regression parameters were estimated by the Maximum Likelihood Method. The Cumulative Residual Method was used to test the adequacy of the regression model through the range of annual average daily traffic per lane. The candidate set of variables was: tunnel length (L), annual average daily traffic per lane (AADTL), percentage of trucks (%Tr), number of lanes (NL), and the presence of a sidewalk. Both for non-severe crashes and severe crashes, prediction-models showed that significant variables are: L, AADTL, %Tr, and NL. A significant year effect consisting in a systematic reduction of severe crashes over time was also detected. The analysis developed in this paper appears to be useful for many applications such as the estimation of accident reductions due to improvement in existing tunnels and/or to modifications of traffic control systems, as well as for the prediction of accidents when different tunnel design options are compared. 相似文献
34.
Ciro Aprea Adriana Greco Angelo Maiorino 《International Journal of Refrigeration》2013,36(8):2148-2159
This paper deals with the problem of R314a substitution with a natural refrigerant fluid. A comparison is performed between R134a and R744 (CO2). R134a is a hydrofluorocarbon with a large direct warming impact (GWP), whereas the R744 contribution is negligible. A comparative exergetic analysis, carried out with experimental tests, has been presented. This paper compares a commercial R134a refrigeration plant and a prototype R744 system working in a trans-critical cycle. Based on the experimental data an exergetic analysis has been carried out on the overall plant and on each device. The overall exergetic performances of the classical vapour compression plant working with R134a are consistently better than that of R744 (from a minimum of 20 to a maximum of 44%). The performance of the individual components of the plant has been analyzed, in order to pinpoint those contributing most to the decrease in the exergetic performance of R744. 相似文献
35.
Dongmei Fan Enrica De Rosa Matthew B. Murphy Yang Peng Christine A. Smid Ciro Chiappini Xuewu Liu Paul Simmons Bradley K. Weiner Mauro Ferrari Ennio Tasciotti 《Advanced functional materials》2012,22(2):282-293
In this study, poly(dl ‐lactide‐co‐glycolide)/porous silicon (PLGA/pSi) composite microspheres, synthesized by a solid‐in‐oil‐in‐water (S/O/W) emulsion method, are developed for the long‐term controlled delivery of biomolecules for orthopedic tissue engineering applications. Confocal and fluorescent microscopy, together with material analysis, show that each composite microsphere contained multiple pSi particles embedded within the PLGA matrix. The release profiles of fluorescein isothiocyanate (FITC)‐labeled bovine serum albumin (FITC‐BSA), loaded inside the pSi within the PLGA matrix, indicate that both PLGA and pSi contribute to the control of the release rate of the payload. Protein stability studies show that PLGA/pSi composite can protect BSA from degradation during the long term release. We find that during the degradation of the composite material, the presence of the pSi particles neutralizes the acidic pH due to the PLGA degradation by‐products, thus minimizing the risk of inducing inflammatory responses in the exposed cells while stimulating the mineralization in osteogenic growth media. Confocal studies show that the cellular uptake of the composite microspheres is avoided, while the fluorescent payload is detectable intracellularly after 7 days of co‐incubation. In conclusion, the PLGA/pSi composite microspheres offer an additional level of controlled release and could be ideal candidates as drug delivery vehicles for orthopedic tissue engineering applications. 相似文献
36.
37.
Daniel Teixidor Francisco Orozco Thanongsak Thepsonthi Joaquim Ciurana Ciro A. Rodríguez Tuğrul Özel 《The International Journal of Advanced Manufacturing Technology》2013,67(5-8):1651-1664
This paper presents investigations on the effects of nanosecond laser processing parameters on depth and width of microchannels fabricated from polymethylmethacrylate (PMMA) polymer. A neodymium-doped yttrium aluminium garnet pulsed laser with a fundamental wavelength of 1,064 nm and a third harmonic wavelength of 355 nm with pulse duration of 5 ns is utilized. Hence, experiments are conducted at near-infrared (NIR) and ultraviolet (UV) wavelengths. The laser processing parameters of pulse energy (402–415 mJ at NIR and 35–73 mJ at UV wavelengths), pulse frequency (8–11 Hz), focal spot size (140–190 μm at NIR and 75 μm at UV wavelengths) and scanning rate (400–800 pulse/mm at NIR and 101–263 pulse/mm at UV wavelengths) are varied to obtain a wide range of fluence and processing rate. Microchannel width and depth profile are measured, and main effects plots are obtained to identify the effects of process parameters on channel geometry (width and depth) and material removal rate. The relationship between process variables (width and depth of laser-ablated microchannels) and process parameters is investigated. It is observed that channel width (140–430 μm at NIR and 100–150 μm at UV wavelengths) and depth (30–120 μm at NIR and 35–75 μm at UV wavelengths) decreased linearly with increasing fluence and increased non-linearly with increasing scanning rate. It is also observed that laser processing at UV wavelength provided more consistent channel profiles at lower fluences due to higher laser absorption of PMMA at this wavelength. Mathematical modeling for predicting microchannel profile was developed and validated with experimental results obtained with pulsed laser micromachining at NIR and UV wavelengths. 相似文献
38.
Marolo C. Alfaro German A. Ciro Kendall J. Thiessen Tony Ng 《Canadian Metallurgical Quarterly》2009,23(3):93-111
This paper reports on a case study of degrading permafrost beneath a road embankment in Northern Manitoba, Canada. Field measurements of ground temperatures for a three-year monitoring period have been used in calibrating the geothermal model developed to reproduce the conditions and trends in the subsurface thermal regime beneath the embankment. The numerical model was used to investigate the future ground thermal regime of the foundation and evaluate the potential impacts of embankment construction and climate change. Particular interest was paid to the foundation soil near the toe of embankment where relatively rapid permafrost degradation was occurring. 相似文献
39.
40.
Cristiano Maria Verrelli Salvatore Pirozzi Patrizio Tomei Ciro Natale Stefano Bifaretti Alessandro Lidozzi 《International journal of control》2018,91(10):2147-2158
A master–slave synchronisation control problem is addressed for current-fed DC and permanent magnet synchronous motors with all uncertain parameters. A measurable exogenous rotor position reference signal, which belongs to the class of biased sinusoidal signals with uncertain bias, amplitude, angular frequency, phase, is to be tracked without assuming its a priori knowledge. An innovative modification of disturbance cancellation techniques allows to prove that an output feedback adaptive nonlinear control scheme, which simply generalises the classical internal-model-based input law, solves the aforementioned problem, with an overall stability proof concerning the entire closed-loop system. The practical effectiveness of the proposed approach is illustrated by experimental results. 相似文献