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Title:

Recovery of tin and copper by recycling of printed circuit boards from obsolete computers

Description:

This paper presents the experimental results for the leaching of printed circuit boards (PCB) from obsolete computers for extracting and recovering tin and copper by means of leaching followed by precipitation. Printed circuit boards were dismantled, cut into small pieces, and fed into a cylinder mill. The powder obtained was leached by using th...

This paper presents the experimental results for the leaching of printed circuit boards (PCB) from obsolete computers for extracting and recovering tin and copper by means of leaching followed by precipitation. Printed circuit boards were dismantled, cut into small pieces, and fed into a cylinder mill. The powder obtained was leached by using the aqueous solutions 2.18N H2SO4, 2.18N H2SO4 + 3.0N HCl, 3.0N HCl, and 3.0N HCl + 1.0N HNO3. The lowest values for the percentage of metal extraction were obtained with 2.18N H2SO4 (2.7% for Sn and lower than 0.01% for Cu), while the 3.0N HCl + 1.0N HNO3 leach system exhibited an extraction of 98% for Sn and 93% for Cu. Precipitates were obtained at different pH values by neutralizing the leach liquors using NaOH. The 3.0N HCl + 1.0N HNO3 leach system presented the highest recovery values from the powder feed (84.1% for Sn and 31.9% for Cu), as well as from the leach liquor (85.8% for Sn and 34.3% for Cu). Minimize

Publisher:

Brazilian Society of Chemical Engineering

Year of Publication:

2009-12-01T00:00:00Z

Document Type:

article

Language:

English

Subjects:

Tin ; Copper ; Recycling ; Electronic scrap ; Hydrometallurgy ; LCC:Chemical engineering ; LCC:TP155-156 ; LCC:Chemical technology ; LCC:TP1-1185 ; LCC:Technology ; LCC:T ; DOAJ:Chemical Engineering ; DOAJ:Chemistry

Tin ; Copper ; Recycling ; Electronic scrap ; Hydrometallurgy ; LCC:Chemical engineering ; LCC:TP155-156 ; LCC:Chemical technology ; LCC:TP1-1185 ; LCC:Technology ; LCC:T ; DOAJ:Chemical Engineering ; DOAJ:Chemistry Minimize

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CC by-nc

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Title:

Unsuitable use of spin and pseudospin symmetries with a pseudoscalar Cornell potential

Description:

The concepts of spin and pseudospin symmetries has been used as mere rhetorics to decorate the pseudoscalar potential [Chin. Phys. B 22 090301 (2013)]. It is also pointed out that a more complete analysis of the bound states of fermions in a a pseudoscalar Cornell potential has already been published elsewhere. ; Comment: 6 pages, to appear in C...

The concepts of spin and pseudospin symmetries has been used as mere rhetorics to decorate the pseudoscalar potential [Chin. Phys. B 22 090301 (2013)]. It is also pointed out that a more complete analysis of the bound states of fermions in a a pseudoscalar Cornell potential has already been published elsewhere. ; Comment: 6 pages, to appear in Chi. Phys. B Minimize

Year of Publication:

2014-08-05

Document Type:

text

Subjects:

Quantum Physics ; High Energy Physics - Phenomenology

Quantum Physics ; High Energy Physics - Phenomenology Minimize

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Title:

Comment on "Wave functions for a Duffin-Kemmer-Petiau particle in a time-dependent potential"

Description:

It is shown that the paper "Wave functions for a Duffin-Kemmer-Petiau particle in a time-dependent potential", by Merad and Bensaid [J. Math. Phys. 48, 073515 (2007)] is not correct in using inadvertently a non-Hermitian Hamiltonian in a formalism that does require Hermitian Hamiltonians. ; Comment: 2 pages

It is shown that the paper "Wave functions for a Duffin-Kemmer-Petiau particle in a time-dependent potential", by Merad and Bensaid [J. Math. Phys. 48, 073515 (2007)] is not correct in using inadvertently a non-Hermitian Hamiltonian in a formalism that does require Hermitian Hamiltonians. ; Comment: 2 pages Minimize

Year of Publication:

2010-03-09

Document Type:

text

Subjects:

Mathematical Physics ; Quantum Physics

Mathematical Physics ; Quantum Physics Minimize

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Title:

Missing solution in a Cornell potential

Description:

Missing bound-state solutions for fermions in the background of a Cornell potential consisting of a mixed scalar-vector-pseudoscalar coupling is examined. Charge-conjugation operation, degeneracy and localization are discussed.

Missing bound-state solutions for fermions in the background of a Cornell potential consisting of a mixed scalar-vector-pseudoscalar coupling is examined. Charge-conjugation operation, degeneracy and localization are discussed. Minimize

Year of Publication:

2013-09-30

Document Type:

text

Subjects:

High Energy Physics - Theory ; Quantum Physics

High Energy Physics - Theory ; Quantum Physics Minimize

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Title:

Spinless bosons embedded in a vector Duffin-Kemmer-Petiau oscillator

Description:

Some properties of minimal and nonminimal vector interactions in the Duffin-Kemmer-Petiau (DKP) formalism are discussed. The conservation of the total angular momentum for spherically symmetric nonminimal potentials is derived from its commutation properties with each term of the DKP equation and the proper boundary conditions on the spinors are...

Some properties of minimal and nonminimal vector interactions in the Duffin-Kemmer-Petiau (DKP) formalism are discussed. The conservation of the total angular momentum for spherically symmetric nonminimal potentials is derived from its commutation properties with each term of the DKP equation and the proper boundary conditions on the spinors are imposed. It is shown that the space component of the nonminimal vector potential plays a crucial role for the confinement of bosons. The exact solutions for the vector DKP oscillator (nonminimal vector coupling with a linear potential which exhibits an equally spaced energy spectrum in the weak-coupling limit) for spin-0 bosons are presented in a closed form and it is shown that the spectrum exhibits an accidental degeneracy. Minimize

Year of Publication:

2011-06-01

Document Type:

text

Subjects:

High Energy Physics - Theory ; Quantum Physics

High Energy Physics - Theory ; Quantum Physics Minimize

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Title:

On the bound-state spectrum of a nonrelativistic particle in the background of a short-ranged linear potential

Description:

The nonrelativistic problem of a particle immersed in a triangular potential well, set forth by N.A. Rao and B.A. Kagali, is revised. It is shown that these researchers misunderstood the full meaning of the potential and obtained a wrong quantization condition. By exploring the space inversion symmetry, this work presents the correct solution to...

The nonrelativistic problem of a particle immersed in a triangular potential well, set forth by N.A. Rao and B.A. Kagali, is revised. It is shown that these researchers misunderstood the full meaning of the potential and obtained a wrong quantization condition. By exploring the space inversion symmetry, this work presents the correct solution to this problem with potential applications in electronics in a simple and transparent way. Minimize

Year of Publication:

2010-03-15

Document Type:

text

Subjects:

Quantum Physics

Quantum Physics Minimize

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Corroborating the equivalence between the Duffin-Kemmer-Petiau and the Klein-Gordon and Proca equations

Description:

It is shown that the Hamiltonian version of the Duffin-Kemmer-Petiau theory with electromagnetic coupling brings about a source term at the current. It is also shown that such a source term disappears from the scenario if one uses the correct physical form for the Duffin-Kemmer-Petiau field, regardless the choice for representing the Duffin-Kemm...

It is shown that the Hamiltonian version of the Duffin-Kemmer-Petiau theory with electromagnetic coupling brings about a source term at the current. It is also shown that such a source term disappears from the scenario if one uses the correct physical form for the Duffin-Kemmer-Petiau field, regardless the choice for representing the Duffin-Kemmer-Petiau matrices. This result is used to fix the ambiguity in the electromagnetic coupling in the Duffin-Kemmer-Petiau theory. Moreover, some widespread misconceptions about the Hermiticity in the Duffin-Kemmer-Petiau theory are discussed. ; Comment: 13 pages, to appears in Phys. Rev. A Minimize

Year of Publication:

2014-07-16

Document Type:

text

Subjects:

High Energy Physics - Theory ; Mathematical Physics ; Quantum Physics

High Energy Physics - Theory ; Mathematical Physics ; Quantum Physics Minimize

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Title:

Trapping of a particle in a short-range harmonic potential well

Description:

Eigenstates of a particle in a localized and unconfined harmonic potential well are investigated. Effects due to the variation of the potential parameters as well as certain results from asymptotic expansions are discussed.

Eigenstates of a particle in a localized and unconfined harmonic potential well are investigated. Effects due to the variation of the potential parameters as well as certain results from asymptotic expansions are discussed. Minimize

Year of Publication:

2012-08-31

Document Type:

text

Subjects:

Quantum Physics ; Mathematical Physics ; Physics - Chemical Physics

Quantum Physics ; Mathematical Physics ; Physics - Chemical Physics Minimize

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Title:

Non-singlet Q-deformed N=(1,0) and N=(1,1/2) U(1) actions

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Description:

In this paper we construct N=(1,0) and N=(1,1/2) non-singlet Q-deformed supersymmetric U(1) actions in components. We obtain an exact expression for the enhanced supersymmetry action by turning off particular degrees of freedom of the deformation tensor. We analyze the behavior of the action upon restoring weekly some of the deformation paramete...

In this paper we construct N=(1,0) and N=(1,1/2) non-singlet Q-deformed supersymmetric U(1) actions in components. We obtain an exact expression for the enhanced supersymmetry action by turning off particular degrees of freedom of the deformation tensor. We analyze the behavior of the action upon restoring weekly some of the deformation parameters, obtaining a non trivial interaction term between a scalar and the gauge field, breaking the supersymmetry down to N=(1,0). Additionally, we present the corresponding set of unbroken supersymmetry transformations. We work in harmonic superspace in four Euclidean dimensions. ; Comment: 14 pages, typos corrected, equation (2.8) replaced by a more illustrative one, version to appear in PLB Minimize

Year of Publication:

2006-05-18

Document Type:

text

Subjects:

High Energy Physics - Theory

High Energy Physics - Theory Minimize

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Title:

Transformaciones bioquímicas durante la fermentación de productos vegetales

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Description:

Different topics dealing with vegetable products fermentation, from manufacturing to microorganisms, and their growth factors, are reviewed. The main pathways for sugar metabolism and degradation reactions of organic and amino acids are described, as well as their influence on sensorial characteristics of the final product. A thorough research o...

Different topics dealing with vegetable products fermentation, from manufacturing to microorganisms, and their growth factors, are reviewed. The main pathways for sugar metabolism and degradation reactions of organic and amino acids are described, as well as their influence on sensorial characteristics of the final product. A thorough research on several areas is considered mandatory, in order to increase the value of fermented vegetable foods. Se revisan los diferentes aspectos relacionados con la fermentación de productos vegetales, desde los procesos de elaboración a los microorganismos responsables y los factores que afectan a su desarrollo. Se presentan, asimismo, las principales reacciones metabólicas de degradación de azúcares y ácidos orgánicos que tienen lugar en los medios de fermentación, así como la influencia de éstas y otras reacciones sobre las características sensoriales del producto elaborado. Finalmente, se citan algunas de las áreas de investigación en las que se considera habría que profundizar para una mayor valoración de los alimentos vegetales fermentados. Minimize

Publisher:

Consejo Superior de Investigaciones Científicas - Consejo Superior de Investigaciones Científicas

Year of Publication:

1992-12-01T00:00:00Z

Document Type:

article

Language:

Spanish ; English

Subjects:

Fermentation ; Information (paper) ; Lactic acid bacteria ; Vegetable ; Bacteria acidoláctica ; Fermentación ; Información (artículo) ; Vegetal ; LCC:Nutrition. Foods and food supply ; LCC:TX341-641 ; LCC:Home economics ; LCC:TX1-1110 ; LCC:Technology ; LCC:T ; DOAJ:Nutrition and Food Sciences ; DOAJ:Agriculture and Food Sciences

Fermentation ; Information (paper) ; Lactic acid bacteria ; Vegetable ; Bacteria acidoláctica ; Fermentación ; Información (artículo) ; Vegetal ; LCC:Nutrition. Foods and food supply ; LCC:TX341-641 ; LCC:Home economics ; LCC:TX1-1110 ; LCC:Technology ; LCC:T ; DOAJ:Nutrition and Food Sciences ; DOAJ:Agriculture and Food Sciences Minimize

Rights:

CC by-nc

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Relations:

http://grasasyaceites.revistas.csic.es/index.php/grasasyaceites/article/view/1132/1139

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