Search results for " effects"

Ni(II) and Pd(II) complexes of camphor-derived diazadiene ligands: steric bulk tuning and ethylene polymerization

1998

Abstract Nickel(II) and palladium(II) centers were coordinated to a series of chiral 1,4-diazadiene ligands. The ligand backbones are camphor derivatives and the imine nitrogens are attached to independently varied 2- and 2,6-substituted aryl groups. Upon activation with methyl-aluminoxane, the dibromo nickel complexes polymerize ethylene and 1-hexene. The polymerization properties are dependent on the steric features of the aryl substituents on the imine nitrogens.

Electronic and Steric Effects: How Do They Work in Ionic Liquids? The Case of Benzoic Acid Dissociation

2010

The need to have a measure of the strength of some substituted benzoic acids in ionic liquid solution led us to use the protonation equilibrium of sodium p-nitrophenolate as a probe reaction, which was studied by means of spectrophotometric titration at 298 K. In order to evaluate the importance of electronic effect of the substituents present on the aromatic ring, both electron-withdrawing and -donor substituents were taken into account. Furthermore, to have a measure of the importance of the steric effect of the substituents both para- and ortho-substituted benzoic acids were analyzed. The probe reaction was studied in two ionic liquids differing for the ability of the cation to give hydr…

Feedback Linearizing Control of Induction Motor Considering Magnetic Saturation Effects

2015

This paper presents an input-output feedback linearization (FL) control technique for rotating induction motors, which takes into consideration the magnetic saturation of the iron core. Starting from a new formulation of the dynamic model taking into consideration the magnetic saturation expressed in a space-state form in the rotor-flux-oriented reference frame, the corresponding FL technique has been developed. To this aim, a particular care has been given to the choice of nonlinear functions interpolating the magnetic parameters versus the rotor magnetizing current and the corresponding magnetic characteristic. The proposed FL technique has been tested experimentally on a suitably develop…

Effect of weather conditions on somatic cell score in Sicilian Valle del Belice ewes

2010

Mastitis susceptibility of Valle del Belice ewes from the south of Sicily to temperature, humidity, precipitation, solar radiation, sun hours, air pressure, wind-speed and wind-direction measured by a public weather station was investigated using 65,848 test-day somatic cell score (SCS) records of 5,237 ewes. All weather parameters had an effect on SCS in a regression approach. Extreme values of maximum and minimum temperaturehumidity indices resulted in increased SCS. Higher precipitation, solar radiation and sun hours resulted in increased SCS, whereas higher air pressure and wind speed resulted in reduced SCS.

La resistenza di interfaccia calcestruzzo poroso-terreni a grana fina per il consolidamento di pendii mediante trincee drenanti profonde

2022

Le trincee drenanti profonde rappresentano uno dei metodi più efficaci per la mitigazione del rischio da frana, in pendii con falda idrica. Esse sono realizzate mediante pannelli o pali secanti. Il riempimento è costituito di calcestruzzo poroso o materiale granulare. Se le trincee sono adeguatamente “innestate” nel terreno stabile e il materiale di riempimento ha sufficiente resistenza e rigidezza come il calcestruzzo poroso, si ha ulteriore in-cremento di resistenza a taglio per effetto shear keys, oltre a quello derivante dalla riduzione delle pressioni in-terstiziali. L’incremento di resistenza è dovuto sia alla resistenza all’interfaccia calcestruzzo–terreni sia a quella intrinseca del…

Beyond the Educational Context: Relevance of Intrinsic Reading Motivation During COVID-19 Confinement in Spain

2021

What role could have intrinsic motivation toward reading in an extraordinary situation like the recent confinement? This research examines the relationship between intrinsic reading motivation (IRM) and reading habits in an adult population considering types of reading (for leisure, work/study, social networks, and news), gender, and distress generated by the coronavirus disease 2019 (COVID-19) pandemic. Participants were 3,849 adults from Spain who were surveyed about their reading practices: before, during the first weeks, and after several weeks of confinement. Linear mixed effects models (LMMs) were used to analyze data. Results showed a three-way interaction between reading frequency, …

Can the absence of solvation of neutral reagents by ionic liquids be responsible for the high reactivity in base-assisted intramolecular nucleophilic…

2005

[reaction: see text] The kinetics of the rearrangement of the Z-phenylhydrazone of 3-benzoyl-5-phenyl-1,2,4-oxadiazole (1a) into the relevant 4-benzoylamino-2,5-diphenyl-1,2,3-triazole (2a) induced by amines have been studied in two room-temperature ionic liquids (IL-1, [BMIM][BF4] and IL-2, [BMIM][PF6]). The data collected show that the reaction occurs faster in ionic liquids than in other conventional solvents previously studied (both polar or apolar, protic or aprotic). Presumably, this could depend on their peculiar ability to minimize the strong substrate-solvent, amine-solvent and amine-amine interactions occurring in conventional solvents.

Concentration growth and thermal stability of gamma-ray induced Germanium lone pair center in Ge-doped sol-gel SiO2

2008

Building sustainable contextual ambidexterity through routines: a case study from information technology firms

2020

The purpose of this paper is to explain the role that routines play in achieving sustainable organisational ambidexterity in information technology (IT) firms. Our exploratory analysis of four case studies reveals the key importance of routines in setting the context for sustainable ambidexterity. Companies build up contextual ambidexterity through routines derived from normalization of processes, normalization of skills, and normalization of results. The findings of the study show that routines support IT professionals to decide whether to exploit or explore in each particular case. Firstly, the enabling character of explicit routines as a result of the normalisation of work processes and …

''Dual'' gravity: Using spatial econometrics to control for multilateral resistance.

2007

We propose a quantity-based `dual' version of the gravity equation that yields an estimating equation with both cross-sectional interdependence and spatially lagged error terms. Such an equation can be concisely estimated using spatial econometric techniques. We illustrate this methodology by applying it to the Canada-U.S. data set used previously, among others, by Anderson and van Wincoop (2003) and Feenstra (2002, 2004). Our key result is to show that controlling directly for spatial interdependence across trade flows, as suggested by theory, significantly reduces border effects because it captures `multilateral resistance'. Using a spatial autoregressive moving average specification, we …