scholarly journals Traitement d'effluents de tannerie-mégisserie par microfiltration tangentielle

2005 ◽  
Vol 14 (4) ◽  
pp. 445-464
Author(s):  
R. Ben Amar ◽  
E. Ellouze ◽  
B. B. Gupta ◽  
A. M. Ayad
Keyword(s):  
Concentration Variable

Dans ce travail un procédé de traitement des effluents issus de l'unité de préparation des peaux des animaux au tannage (travail en rivière) en tannerie-mégisserie a été étudié en utilisant la technique de microfiltration tangentielle sur membrane minérale en céramique. Les performances de ce procédé en terme de flux de filtration et de rendement épuratoire dépendent aussi bien des paramètres hydrodynamiques de filtration que de la qualité des effluents (collectés en été et en printemps) issus des différents bains de traitement et de rinçage des peaux dans l'atelier de rivière. Le flux de filtration varie entre 15 l/h.m2 pour l'effluent de printemps et 90 l/h.m2 pour l'effluent d'été. Les paramètres hydrodynamiques optimaux ont également été déterminés: la vitesse de circulation U=3 m/s, la pression transmembranaire Ptm=2 bar et la température T=43°C. L'étude de la microfiltration à concentration variable conduit à des facteurs de concentration volumique (FCV) de 6,5 pour l'effluent de l'été et de 2,4 pour l'effluent de printemps.

scholarly journals The Influence of Corporate Governance on Intellectual Capital Disclosure: Evidence from Bank on Indonesian Stock Exchange 2015-2019

2021 ◽  
pp. 1-10
Author(s):  
Indrayati Dra., Ak., MSA., CA ◽  
Erlin Melani, SE., Ak., MSA., CA ◽  
Slamet Slamet
Keyword(s):  
Corporate Governance ◽  
Intellectual Capital ◽  
Audit Committee ◽  
Annual Report ◽  
Stock Exchange ◽  
Sampling Technique ◽  
Ownership Concentration ◽  
Concentration Variable ◽  
External Auditor ◽  
Positive Effect

The purpose of this study was to examine the effect of Corporate Governance on Intellectual Capital Disclosure. The sample used in this study consisted of 22 banking companies listed on the Indonesia Stock Exchange in 2015-2019. The data used is in the form of an annual report. The sampling technique in this study was to use purposive sampling. This study uses multiple regression analysis. The statistical analysis results show that partially the audit committee and external auditor variables have a significant positive effect on intellectual capital disclosure. Meanwhile, the independent commissioner variable has no significant effect on intellectual capital disclosure. The ownership concentration variable harms intellectual capital disclosure. Simultaneously, the variables of the independent commissioner, ownership concentration, audit committee, and external auditor have a significant effect on intellectual capital disclosure.

scholarly journals Evolución de la atención, concentración y rendimiento académico tras una intervención basada en descansos activos

2021 ◽  
Vol 24 (3) ◽  
Author(s):  
Silvia Arribas-Galarraga ◽  
Julen Maiztegi Kortabarria
Keyword(s):  
Measurement Instrument ◽  
Measured Data ◽  
Spanish Language ◽  
Control Group ◽  
Spelling Performance ◽  
Language And Literature ◽  
Concentration Variable ◽  
The Subject ◽  
Previous Phase ◽  
Experimental Group

El objetivo principal de la investigación ha sido analizar la evolución de la atención y concentración en jóvenes estudiantes, tras la implementación de un programa basado en descansos activos o Activity Breaks en la asignatura de Lengua Castellana y Literatura. La muestra, compuesta por 31 estudiantes, 14 chicas y 17 chicos, del primer curso de la Enseñanza Secundaria Obligatoria (edad media 12.13 años), se dividió en dos grupo clase: grupo control y grupo experimental. La intervención, de 7 semanas, implementada durante las lecciones en el aula, permitió aumentar la cantidad de actividad física diaria. Mediante el instrumento de medida “Test de atención D2”, se midió la atención y la concentración, y a través de un texto dictado el rendimiento ortográfico, los datos se recogieron tanto en la fase previa, como tras la intervención. Los resultados indican un aumento estadísticamente significativo tanto en la variable atención como en la variable concentración en el grupo experimental. En cuanto a los contenidos relativos a Lengua Castellana y Literatura, ortografía, no se observaron diferencias estadísticamente significativas. The main objective of the research has been to study the evolution of attention and concentration after the implementation of a programme based on Activity Breaks in the subject Spanish Language and Literature. The sample, formed by 31 students, 14 girls and 17 boys, from the first course o Compulsory Secondary Education (average age 12.13 years), was divided into two class groups, control group and experimental group. The intervention, of 7 weeks, implemented during the lessons in the classroom, allowed the amount of daily physical activity to be increased. By the measurement instrument “Attention Test D2” attention and concentration and by the text dictated spelling performance was measured, data was collected in the previous phase and after the intervention. The results indicate a statically significant increase in attention and concentration variable in experiential group. Regarding the Spanish Language and Literature contents, orthography, no statistically significant differences were observed.

A Mixed Natural and Concentration Variable Formulation for Chemical Flood Simulation

2017 ◽  
Author(s):  
Xundan Shi ◽  
Choongyong Han ◽  
Christian Wolfsteiner ◽  
Yih-Bor Chang ◽  
Mark Schrader
Keyword(s):  
Flood Simulation ◽  
Concentration Variable

Dependence of the Ionization Energy of Phosphorous Donor in 4H-SiC on Doping Concentration

2006 ◽  
Vol 527-529 ◽  
pp. 597-600 ◽  
Author(s):  
Sunil Rao ◽  
T. Paul Chow ◽  
I. Bhat
Keyword(s):  
Ionization Energy ◽  
Doping Concentration ◽  
Variable Temperature ◽  
Measured Data ◽  
Least Square ◽  
High Dose ◽  
Ionization Energies ◽  
Concentration Variable ◽  
Hall Effect Measurements ◽  
Lower Sheet Resistance

4H-SiC implanted with high dose of phosphorus has been shown to exhibit lower sheet resistance than 4H-SiC implanted with high dose of nitrogen. In this paper, we have implanted various doses (1x1014cm-2, 2x1014cm-2, 1x1015cm-2 and 4x1015cm-2) of phosphorus into 4H-SiC in order to extract the ionization energy of phosphorus in 4H-SiC as a function of the doping concentration. Variable temperature Hall effect measurements were performed in the temperature range from 60-600K. Least square fits using the charge neutrality equation with two donor levels were used to extract the ionization energies and donor concentrations from the measured data. The ionization energies for both, the hexagonal (53meV, 49meV and 26meV) and the cubic (109meV, 101meV and 74meV) site decreased as the donor concentration (5x1018cm-3, 9.8x1018cm-3 and 3.4x1019cm-3) increased.

scholarly journals Effet Hall dans des solutions électrolytiques de concentration variable

1980 ◽  
Vol 41 (23) ◽  
pp. 575-580 ◽  
Author(s):  
M. Abbes ◽  
R. Gérard ◽  
P. Gérard ◽  
M. Meton ◽  
E.J. Picard
Keyword(s):  
Concentration Variable

scholarly journals The influence of the non-linear diffusion on the mass transfer of a packaging contaminant into foodstuffs

2018 ◽  
Vol 26 (2) ◽  
pp. 135-144 ◽  
Author(s):  
Gheorghe Juncu
Keyword(s):  
Mass Transfer ◽  
Diffusion Coefficient ◽  
Balance Equation ◽  
Mass Balance Equation ◽  
Linear Mass ◽  
Linear Diffusion ◽  
Kirchhoff Transformation ◽  
Mass Transfer Mechanism ◽  
Concentration Variable ◽  
Non Linear

Abstract The unsteady mass transfer of the packaging constituents to a food has been analysed. The diffusion coefficient inside the packaging was considered concentration - variable while the food was considered concentration spatially gradientless. A well-known technique (Kirchhoff transformation) was used to solve the non-linear mass balance equation. The influence of the non-linear diffusion on the mass transfer mechanism and rate was analysed for different values of the partition coefficient and dilution coefficient.

Transport properties and the structure of vanadium phosphate glasses

1977 ◽  
Vol 55 (5) ◽  
pp. 436-441 ◽  
Author(s):  
B. D. Jordan ◽  
C. Calvo
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Composition Range ◽  
Phosphate Glasses ◽  
Vanadium Phosphate ◽  
Jump Frequency ◽  
X Ray ◽  
Concentration Variable ◽  
Hopping Model ◽  
Vanadium Ion

The adiabatic hopping model for the electrical conductivity of the vanadium phosphate glasses, V1+xP1−xO5−c/2, is examined in terms of their structures as derived from recent X-ray studies. These indicate that the relevant concentration variable for rationalizing the Seebeck coefficient data is c, the fraction of non-tetrahedral vanadium ion sites which are polarons. The polarons interlayer coordination number is 3. The average hopping distance varies by only 5% for 0 ≤ x ≤ 1. The experimental conductivities compared with[Formula: see text]suggest that n is near 3 and that the jump frequency v0 varies by nearly a factor of 3 over the composition range.

Hyperchirality: a mathematically convenient and biochemically possible model for the kinetics of morphogenesis

1978 ◽  
Vol 202 (1148) ◽  
pp. 361-397 ◽  
Keyword(s):  
Quaternary Structure ◽  
Specific Model ◽  
Spontaneous Resolution ◽  
Kinetic Properties ◽  
Single Variable ◽  
Concentration Variable ◽  
A Cell ◽  
Parallel Reactions ◽  
Kinetics Of ◽  
Inhibitory Interactions

Two general problems in morphogenesis are discussed: (a) scaling of the repeating unit of a pattern to the overall size of the organism; (b) biochemically realistic mechanisms for highly localized autocatalysis to produce pattern on a wall or membrane of a single cell. These problems are approached by comparing the Mills (1932) model for spontaneous resolution by bimolecular autocatalysis in formation of a pair of enantiomers (D and L) with the Turing (1952) model for morphogenesis by catalytic and inhibitory interactions of two morphogens (X and Y) very unsymmetrically matched in kinetic properties. A model for a morphogen M is proposed in the form of a pair of enantiomers M D and M L , with the out-of-equilibrium morphogen concentration variable in the Turing equations being the optical asymmetry M = M D — M L . Formation of M out of a precursor (pro-morphogen A), with two reactions A → M D and A → M L to control the single variable M , allows the Turing theory to encompass a variety of ways in which pattern unit scales with overall size. To this end, formation of morphogens by parallel reactions exceeding in number the morphogen concentration variables is a general principle independent of the reality of this specific model. More tentatively, the model is put forward as a possible real structure for morphogens on a cell wall or membrane. Both M D and M L must be present. It is suggested that the lowest level of organization at which structures of two chiralities might be found, when their molecules are of one chirality only, is the attachment of an enzyme polymer, with definite quaternary structure, to the cell surface. The enantiomers may then be the same polymeric assembly facing inwards or outwards. The word hyperchirality is suggested for this kind of asymmetry. Some morphogenetic features of the single-celled desmid alga Micrasterias are discussed, to illustrate the geometrical problems of translating morphogen kinetics into development of shape, and to show that the number of active morphogens and the dimensionality of the space in which they act may decrease during development.

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