2,019 research outputs found
Generalization of Linearized Gouy-Chapman-Stern Model of Electric Double Layer for Nanostructured and Porous Electrodes: Deterministic and Stochastic Morphology
We generalize linearized Gouy-Chapman-Stern theory of electric double layer
for nanostructured and morphologically disordered electrodes. Equation for
capacitance is obtained using linear Gouy-Chapman (GC) or
Debye-ckel equation for potential near complex
electrode/electrolyte interface. The effect of surface morphology of an
electrode on electric double layer (EDL) is obtained using "multiple scattering
formalism" in surface curvature. The result for capacitance is expressed in
terms of the ratio of Gouy screening length and the local principal radii of
curvature of surface. We also include a contribution of compact layer, which is
significant in overall prediction of capacitance. Our general results are
analyzed in details for two special morphologies of electrodes, i.e.
"nanoporous membrane" and "forest of nanopillars". Variations of local shapes
and global size variations due to residual randomness in morphology are
accounted as curvature fluctuations over a reference shape element.
Particularly, the theory shows that the presence of geometrical fluctuations in
porous systems causes enhanced dependence of capacitance on mean pore sizes and
suppresses the magnitude of capacitance. Theory emphasizes a strong influence
of overall morphology and its disorder on capacitance. Finally, our predictions
are in reasonable agreement with recent experimental measurements on
supercapacitive mesoporous systems
Effect of Altitude on the Phenology and Fruit Quality Attributes of Apricot (Prunus armeniaca L.) Fruits
Consumer concern about poor taste of fresh apricots is increasing and knowledge about the more suitable production requirement is essential. Genetic component influencing apricots quality is well known. However, there is limited information on environmental effect on fruit quality. This study aims to evaluate influence of altitude on phenological and fruit quality characters of apricot genotypes. Fruits from 162 genotype were collected from nine locations from 3006-3346 m asl in trans-Himalaya. The altitude had a marked influence on date of flowering, fruit weight, moisture and TSS content. For every 100 m increase in altitude, flowering and fruit ripening delayed by 3.3 and 7.1 day, respectively. Inverse relationship between altitude and fruit weight (R2=0.310) was observed. For every 100 m increase in altitude the fruit weight decrease by 0.5 g. Fruit moisture content decreased significantly with increase in elevation (R2=0.585). Decrease in moisture content was 1.9% for every 100 m increase in elevation. Altitude showed linear relationship with fruit TSS content (R2=0.726). For every 100 m increase in altitude, the fruit TSS increased by 1.2ºBrix. Knowledge from the present study on the impact of altitude on fruit quality characters provides a useful guide for selecting orchard location towards improving fruit qualit
Frege on the Generality of Logical Laws
Frege claims that the laws of logic are characterized by their “generality,” but it is hard to see how this could identify a special feature of those laws. I argue that we must understand this talk of generality in normative terms, but that what Frege says provides a normative demarcation of the logical laws only once we connect it with his thinking about truth and science. He means to be identifying the laws of logic as those that appear in every one of the scientific systems whose construction is the ultimate aim of science, and in which all truths have a place. Though an account of logic in terms of scientific systems might seem hopelessly antiquated, I argue that it is not: a basically Fregean account of the nature of logic still looks quite promising
(7-Chloro-2-oxo-2H-chromen-4-yl)methyl piperidine-1-carbodithioate
In the title compound, C16H16ClNO2S2, the piperidine ring is in a chair conformation. In the coumarin ring system, the dihedral angle between the benzene and pyran rings is 3.5 (1)°. In the crystal, a weak C—H⋯O hydrogen bond links molecules into chains along [001]. In addition, π–π stacking interactions are present involving the benzene and pyran rings, with a centroid-to-centroid distance of 3.712 (2) Å. The crystal studied is a nonmerohedral twin with refined components 0.221 (1) and 0.779 (1)
(6-Methoxy-2-oxo-2H-chromen-4-yl)methyl pyrrolidine-1-carbodithioate
In the title compound, C16H17NO3S2, the 2H-chromene ring is close to being planar [maximum deviation = 0.034 (2) Å] and the pyrrolidine ring is twisted about the C—C bond opposite the N atom. The dihedral angle between the ring-system planes is 75.24 (16)° and an intramolecular C—H⋯S interaction occurs. In the crystal, molecules are linked by C—H⋯O hydrogen bonds and the packing also exhibits π–π interactions, with a distance of 3.6106 (13) Å between the centroids of the benzene rings of neighbouring molecules
School tuck shops in South Africa—an ethical appraisal
It can be postulated that schools have an ethical responsibility to protect children from an unhealthy food environment. Against
the backdrop of stunting, overweight and micronutrient deficiencies prevalent in South African children, the aim of this scoping
study is to review information available on foods sold to school children within an ethical framework. While some schools have
a formal tuck shop, at other schools, food vendors sell food either on or outside the school premises. Ten studies, of which two
were national, fit the selection criteria for this study. Available data show that mostly unhealthy food options are sold to South
African school children; with low-nutrient energy-dense foods (e.g. chips, sweets) and sugar sweetened beverages being the
most popular. The Integrated School Health Policy provide a policy framework for achieving healthy school food environments in
South Africa, and several guidelines are available in South African to assist school tuck shops to sell healthier options. Children’s
preference for unhealthy foods, the cost of healthier food options and a lack of proper facilities may however be barriers for
implementing healthy tuck shops. An action stronger than merely providing guidelines may therefore be needed. Cognisance
needs to be taken of conflicting value based arguments within ethical perspectives. Given these conflicts, the authors argue that
an Ethics of Responsibility contributes to the debate of the best and supports the notion that society at large has a responsibility
to protect vulnerable communities of which school children are part. Presently an ethical vacuum exists in terms of rights and
responsibilities which this study hopes to address.DHE
Treating patients as persons : a capabilities approach to support delivery of person-centered care
Peer reviewedPublisher PD
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