Search results for "Stability"
showing 10 items of 3085 documents
Interactive roll stabilization comparative analysis for large yacht: gyroscope versus active fins
2020
The problem of the active stabilization of ship motions is particularly important in the case of pleasure boats or in any case of passenger ships, since the commercial value of the ship is directly related to the comfort of the load transported in this case “people”, considered as stresses induced on them by the vessel movements, with particular attention to roll, given the ship geometric characteristics. Naval architects developed trough the years different solutions to reduce the roll of the ship, and consequentially to increase the passengers comfort, and the development of this solutions followed the progress of technology. Active fins have been the most used, but now the gyroscope solu…
Corynosoma acanthocephalans in their paratenic fish hosts in the northern Baltic Sea
2003
En 1996-1997, nous avons etudie les stages cystacanthes de trois especes de Corynosoma (Acanthocephala), C. strumosum et C. semerme, ainsi qu'une nouvelle espece C. magdaleni parasite du chabot a quatre cornes (Myoxocephalus quadricornis) dans le golfe de Bothnie. Les longueurs du tronc et du proboscis permettent de differencier les trois especes de parasites. La stabilite temporelle de l'infection par Corynosoma est etudiee en comparant nos resultats a ceux obtenus dans la meme zone geographique centrale et cotiere) en 1977-1982 (Valtonen, 1983a). Comme C. magdaleni et C. strumosum n'etaient pas differenciees a cette epoque, elles ont ete groupees sous l'appellation "C. strumosum" pour les…
The effect of osseodensification on implant stability and bone density: A prospective observational study.
2019
Background The aims of this study were to evaluate the effect of implant site preparation in low-density bone using osseodensification method in terms of implant stability changes during the osseous healing period and peri-implant bone density using CBCT. Material and Methods This prospective observational clinical study included 24 patients who received 46 dental implants that were installed in low-density bone using the osseodensification method. CBCT was used to measure the bone density pre- and postoperatively and implant stability was measured using Periotest® immediately after implant insertion and then after 6 weeks and 12 weeks postoperatively. The data were analyzed using paired t-…
Measurement of dental implant stability by resonance frequency analysis : a review of the literature
2008
Dental implant treatment is an excellent option for prosthetic restoration that is associated with high success rates. Implant stability is essential for a good outcome. The clinical assessment of osseointegration is based on mechanical stability rather than histological criteria, considering primary stability (absence of mobility in bone bed after implant insertion) and secondary stability (bone formation and remodelling at implant-bone interface). The aim of this study was to review the literature on Resonance Frequency Analysis (RFA) as a method for measuring dental implant stability. An online search of various databases was conducted on experimental and clinical research published betw…
Bank Erosion and Secondary Circulation in a Meandering Laboratory Flume
2014
Abstract This paper reports peculiar results of experimental investigation on the secondary circulation motion of flow along a meander wave. Experiments were conducted in a large amplitude meandering laboratory channel for two values of the width-to-depth ratio. Here attention is focalized on how secondary motion affects the bank shear stress distribution, influencing the stability of the outer bank. The analysis essentially highlights that, especially for small width-to-depth ratio, as the channel curvature increases, besides the classical central-region secondary circulation cell a counter-rotating circulation cell forms in the outer-bank region. Such counter-rotating circulation cell all…
Optional Sampling Theorems
2020
In Chapter 9 we saw that martingales are transformed into martingales if we apply certain admissible gambling strategies. In this chapter, we establish a similar stability property for martingales that are stopped at a random time (optional sampling and optional stopping). In order also to obtain these results for submartingales and supermartingales, in the first section, we start with a decomposition theorem for adapted processes. We show the optional sampling and optional stopping theorems in the second section. The chapter finishes with the investigation of random stopping times with an infinite time horizon.
Marginal contribution, reciprocity and equity in segregated groups: Bounded rationality and selforganization in social networks
2007
We study the formation of social networks that are based on local interaction and simple rule following. Agents evaluate the profitability of link formation on the basis of the Myerson-Shapley principle that payoffs come from the marginal contribution they make to coalitions. The NP-hard problem associated with the Myerson-Shapley value is replaced by a boundedly rational 'spatially' myopic process. Agents consider payoffs from direct links with their neighbours (level 1), which can include indirect payoffs from neighbours' neighbours (level 2) and up to M-levels that are far from global. Agents dynamically break away from the neighbour to whom they make the least marginal contribution. Com…
The dual role of p53: DNA protection and antioxidant.
2011
The classical functions of p53 protein are those related to its role on DNA damage, cell growth arrest, senescence and apoptosis. For this reason it is called 'the guardian of the genome' and is considered one of the most important players in the development of cancer. However, more recently it has been show that p53 is not only involved in cancer, but also in ageing. p53 is stimulated by stress, which in turn results in the activation of a wide range of transcriptional targets. Low-intensity stress will activate p53 in a manner which results in antioxidant response, thus protecting against ageing because of its antioxidant function. On the contrary, high-intensity activation of p53 will re…
Output Feedback Control of Discrete Impulsive Switched Systems with State Delays and Missing Measurements
2013
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2013/283426 Open Access This paper is concerned with the problem of dynamic output feedback (DOF) control for a class of uncertain discrete impulsive switched systems with state delays and missing measurements. The missing measurements are modeled as a binary switch sequence specified by a conditional probability distribution. The problem addressed is to design an output feedback controller such that for all admissible uncertainties, the closed-loop system is exponentially stable in mean square sense. By using the average dwell time approach a…
Sequestering ability of polyaminopolycarboxylic ligands towards dioxouranium(VI) cation
2006
Abstract In the present paper, some results of an investigation (at t = 25 °C by potentiometry, ISE-H+ glass electrode) on the sequestering ability of five different polyaminopolycarboxylic ligands [Nitrilotriacetate (NTA), ethylenediamine-N,N,N′,N′-tetraacetate (EDTA), ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetate (EGTA), diethylenetriamine-N,N,N′,N″,N″-pentaacetate (DTPA), triethylenetetraamine-N,N,N′,N″,N′′′,N′′′-hexaacetate (TTHA)] towards dioxouranium(VI) cation in sodium chloride aqueous solutions, at I = 0.7 mol L−1 are reported. Calculations performed on potentiometric data gave evidence of the formation of the following species (log β in parenthesis): UO2(NTA)H0 (12…