Search results for "Step"
showing 10 items of 509 documents
Dynamics of the caring family
2003
When several individuals simultaneously provide for offspring, as in families, the effort of any one individual will depend on the efforts of the other family members. This conflict of interest among family members is made more complicated by their relatedness because relatives share genetic interest to some degree. The conflict resolution will also be influenced by the differences in reproductive value between breeders and helpers. Here, we calculate evolutionarily stable provisioning efforts in families with up to two helpers. We explicitly consider that the behavioral choices are made in a life-history context, and we also consider how group sizes change dynamically; this affects, for ex…
A nonlinear algorithm for monotone piecewise bicubic interpolation
2016
We present an algorithm for monotone interpolation on a rectangular mesh.We use the sufficient conditions for monotonicity of Carlton and Fritsch.We use nonlinear techniques to approximate the partial derivatives at the grid points.We develop piecewise bicubic Hermite interpolants with these approximations.We present some numerical examples where we compare different results. In this paper we present an algorithm for monotone interpolation of monotone data on a rectangular mesh by piecewise bicubic functions. Carlton and Fritsch (1985) develop conditions on the Hermite derivatives that are sufficient for such a function to be monotone. Here we extend our results of Arandiga (2013) to obtain…
Sub-critical filtration conditions of commercial hollow-fibre membranes in a submerged anaerobic MBR (HF-SAnMBR) system: The effect of gas sparging i…
2012
A submerged anaerobic MBR demonstration plant with two commercial hollow-fibre ultrafiltration systems (PURON®, Koch Membrane Systems, PUR-PSH31) was operated using municipal wastewater at high levels of mixed liquor total solids (MLTS) (above 22gL -1). A modified flux-step method was applied to assess the critical flux (J C) at different gas sparging intensities. The results showed a linear dependency between J C and the specific gas demand per unit of membrane area (SGD m). J C ranged from 12 to 19LMH at SGD m values of between 0.17 and 0.5Nm 3h -1m -2, which are quite low in comparison to aerobic MBR. Long-term trials showed that the membranes operated steadily at fluxes close to the est…
Variable Step Size P&O Algorithms for Coalescing Pump/Deoiling Hydrocyclone Produced Water Treatment System
2020
This paper presents three variable step size P&O algorithms for optimizing the separation efficiency of a coalescing pump/deoiling hydrocyclone produced water treatment system. By continuously adjusting the pumping pressure, and subsequently the coalescing effect, the algorithms are used to minimize the oil concentration downstream the hydrocyclone. Due to the variable step size, the algorithms react rapidly to changes in the upstream produced water characteristics, at the same time as they reduce (or eliminate) steady-state oscillations. Based on both simulation and experimental testing, the study discusses advantages and disadvantages of the algorithms.
Analysis of rill step–pool morphology and its comparison with stream case
2021
In this paper, the morphology of step–pool features is analysed using rill measurements and literature data for streams. Close-range photogrammetry was used to carry out ground measurements on rills with step–pool units, shaped on a plot having slope equal to 14, 15, 22, 24 and 26%. Data were used to compare the relationships between H/L, in which H is the step height and L is the step length, and the mean gradient of the step–pool sequence, Sm, for streams or the slope of the step–pool unit, S, for rills. The relationship of H/L against Sm is widely used to test the occurrence of the maximum flow resistance condition in streams, which is associated with the range 1 ≤ (H/L)/Sm ≤ 2. Further …
I RODITORI DI CAVA MONTICINO (BRISIGHELLA, RA)
2021
Rodents are the most abundant group of small mammals occurring in Brisighella deposits. They are represented by 12 species in total, among which 2 hamsters (Apocricetus cf. barrierei and Ruscinomys cf. lasallei), 2 dormice (Muscardinus sp. and Myomimus sp.), 1 porcupine (Hystrix (Hystrix) depereti), 2 sciurids (Atlantoxerus cf. rhodius and Hylopetes sp.) and 5 species of muridae (Apodemus cf. gudrunae, Centralomys benericettii, Occitanomys sp, Paraethomys meini and Stephanomys debruijni). This association suggests a relatively dry open environment, interrupted by forest environment with more or less dense underground.
Generation of defects in amorphous SiO(2) assisted by two-step absorption on impurity sites.
2011
Generation of the Si dangling bond defect in amorphous SiO(2) (E' centre) induced by tunable pulsed UV laser radiation was investigated by in situ optical absorption measurements. The defect generation efficiency peaks when the photon energy equals ∼5.1 eV, it depends quadratically on laser intensity and is correlated with the native linear absorption due to Ge impurities. We propose a model in which the generation of E' is assisted by a two-step absorption process occurring on Ge impurity sites.
Affinity scale between a carrier and a drug in DPI studied by atomic force microscopy.
2002
The dry powder inhalers (DPIs) consist, in the most cases, of ordered mixture where the particles adhesion results of interactions between the drug and the carrier. Generally, one step of production process is the micronization of the drug particles in order to reduce the size for ordered mixing optimization. But this operation is known to partially create an amorphous surface. In this case, surrounding storage conditions, like relative humidity (RH), are able to modify the percentage of amorphous drug surface. The aim of this study was to investigate surface reactivity, surface energy and direct force measurements by atomic force microscopy (AFM) between lactose (carrier) and zanamivir (dr…
Designing solid optical sensors for in situ passive discrimination of volatile amines based on a new one-step hydrophilic PDMS preparation
2016
Abstract We reported an optimal material for embedding chemoresponsive dyes based on modified commercial PDMS. A new approach to impart hydrophilicity to H-PDMS in an unique step was developed by addition of tetraethyl orthosilicate (TEOS) and in absence of basic or acid aqueous mixtures or hydroxyl-compounds during the PDMS coating process. This incorporation significantly enhances the performance of PDMS-based devices for sensing applications. New colorimetric sensors for passive detection and in situ discrimination of volatile amines have been obtained. The limit of detection achieved was 1.5 mg m −3 for both, dimethylamine and methylamine, suitable to control real working atmospheres. T…
Integrazione di celle solari di terza generazione nel vetromattone per la realizzazione di pannelli traslucidi fotovoltaici. Analisi prestazione e st…
2013
L’articolo illustra i primi risultati ottenuti nell’ambito dell’analisi prestazionale del vetromattone fotovoltaico, un prodotto edilizio innovativo derivato dall’integrazione di celle fotovoltaiche di terza generazione (DSSC) nel vetromattone, ideato per la realizzazione di involucri traslucidi energeticamente effi cienti ed “attivi”, in grado di ridurre i consumi energetici degli edifi ci e di produrre, al contempo, energia verde. L’analisi è stata condotta su quattro differenti ipotesi di integrazione. Attraverso simulazioni numeriche si è effettuata una valutazione dell’energia assorbita dagli strati attivi oltre che delle prestazioni ottiche complessive del dispositivo. Lo studio anali…