Search results for "Stability"
showing 10 items of 3085 documents
M11_Microfluidics_for_CNT
2018
The subtle solubility of water in n-decane causes leaking of the droplet content. If the n-decane flows by static droplets, it carries the water slowly away up to the total disappearance of the droplets.
Effect of air-absorbed oxygen and moisture on the chemical stability of photoexcitedMg,ZnandEuphthalocyanines in dimethylformamide
2006
Absorption of oxygen and moisture from air by MPc-DMF systems was studied and related to the molecular stability demonstrated by phthalocyanine complexes (unsubstituted MPc's : MgPc , ZnPc and EuPc2; Pc = phthalocyanine ligand, C32H16N8) subjected to UV irradiation. A lower stability of air-exposed dimethylformamide solutions is observed and is due to a specific affinity for molecular oxygen revealed by the Pc macrocycle. SEM results proved oxygen molecules fixed to the phthalocyanine solids by forces strong enough to sustain desorption under vacuum. Absorption curves determined for MPc-DMF systems also indicate oxygen accommodated by the phthalocyanine moiety. This explains the predominant…
Structural analysis, phase stability and electrochemical characterization of Nb doped BaCe0.9Y0.1O3−x electrolyte for IT-SOFCs
2012
Abstract To improve the chemical stability of high temperature proton conductors based on barium cerate, electrolyte powders doped with different amounts of niobium were synthesized by the citrate–nitrate auto-combustion method. Pure single phases of BaCe 0.9− x Nb x Y 0.1 O 3− x (BCYN, 0.03 ≤ x ≤ 0.12) were obtained by thermal treatment at 1000 °C. Sintering at 1450 °C for 10 h produced dense pellets. X-ray absorption spectroscopy allowed to define the dopant ion insertion site and the co-dopant valency. Treatments in pure CO 2 atmosphere at 700 °C for 3 h and subsequent XRD analysis were carried out to probe the chemical stability of the produced electrolytes. The influence of the prese…
Positive L1 observer design for positive Switched systems
2014
Published version of an article in the journal: Circuits, Systems, and Signal Processing. Also available from the publisher at: http://dx.doi.org/10.1007/s00034-013-9737-6 This paper investigates the problem of L1 observer design for positive switched systems. Firstly, a new kind of positive L1 observer is proposed for positive switched linear delay-free systems with observable and unobservable subsystems. Based on the average dwell time approach, a sufficient condition is proposed to ensure the existence of the positive L1 observer. Under the condition obtained, the estimated error converges to zero exponentially, and the L1 -gain from the disturbance input to the estimated error is less t…
Stability of Embankments Resting on Foundation Soils with A Weak Layer
2021
The presence of weak layers in geotechnical systems, including soil or rock masses, both natural and man-made, is more frequent than is normally believed. Weak layers can affect both failure mechanisms, in drained and in undrained conditions, as well as in static and seismic conditions, and the safety factor. In the present study, conducted numerically using the finite-element method (FEM) Plaxis 2D code, the influence of a horizontal thin weak layer on stress and strain distribution, on failure mechanisms and on the overall stability of an embankment was evaluated. The results obtained prove that when the weak layer is located at a significant depth from the foundation plane, the failure m…
Efficient finance regulator as supporter for financial stability of inhabitants
2020
Recent developments in banking sector in Latvia especially related with PNB Bank where bank accounts of many retired people were located leads to requirements for proficiency of Finance Regulator which has to be efficiently financed, stable and professional. In different countries Finance Regulators have different models of their financing. Aim of the study is to investigate different approaches for Finance Regulator financing and analyse expert views on possible development of Finance Regulator financing model in Latvia. Research methods applied: scientific publications and previous conducted research results analysis and expert survey for possible financing model changes in Latvia. In exp…
STUDY OF SAGITTAL SPINAL ROM IN ELDERLY WOMEN AFTER A SPECIFIC FLEXIBILITY-TRAINING PROGRAM
2013
The reduction of spinal mobility is one luckless consequence of the aging process. In particular, scarcity of exercise appears to be the principal reason of aging-related spinal dysfunction syndrome, which is characterized by adaptive shortening of soft tissue and a partial loss of range of spinal motion (1). Several recommendations promoting the spinal flexibility in elderly people are based on stretching programs that include static and ballistic exercises and PNF techniques (2). Several studies showed that specific training programs could improve body balance (3), bodyweight distribution on feet (4), muscle strength and flexibility (5) in elders. In particular, Imagama et al. (2011) show…
Equilibrium fluid-crystal interfacial free energy of bcc-crystallizing aqueous suspensions of polydisperse charged spheres
2015
The interfacial free energy is a central quantity in crystallization from the meta-stable melt. In suspensions of charged colloidal spheres, nucleation and growth kinetics can be accurately measured from optical experiments. In previous work, from this data effective non-equilibrium values for the interfacial free energy between the emerging bcc-nuclei and the adjacent melt in dependence on the chemical potential difference between melt phase and crystal phase were derived using classical nucleation theory. A strictly linear increase of the interfacial free energy was observed as a function of increased meta-stability. Here, we further analyze this data for five aqueous suspensions of charg…
Mechanics of invagination and folding: Hybridized instabilities when one soft tissue grows on another
2015
We address the folding induced by differential growth in soft layered solids via an elementary model that consists of a soft growing neo-Hookean elastic layer adhered to a deep elastic substrate. As the layer/substrate modulus ratio is varied from above unity towards zero we find a first transition from supercritical smooth folding followed by cusping of the valleys to direct subcritical cusped folding, then another to supercritical cusped folding. Beyond threshold the high amplitude fold spacing converges to about four layer thicknesses for many modulus ratios. In three dimensions the instability gives rise to a wide variety of morphologies, including almost degenerate zigzag and triple-ju…
3PC-030 Physical, chemical and microbiological stability of sirolimus 0.4% in topical formulations
2019
Background Facial angiofibromas in tuberous sclerosis are an aesthetic problem within the clinical context of the disease. There are currently few stability studies that allow selecting the best topical sirolimus therapy. Purpose To improve the formulation of sirolimus 0.4% for the treatment of facial angiofibromas in tuberous sclerosis and to determine the period of validity (physical, chemical and microbiological stability) of the proposed formulations. Material and methods Three formulations of sirolimus 0.4% were prepared (each in duplicate, A and B). Facilities and equipment: biological safety cabinet with individual protection equipment for the manipulator. Conditions: aluminum tubes,…