Andreas Ries

Prof. Dr. Andreas Ries

Universidad Nacional de Asunción, CEMIT, San Lorenzo, Central, Paraguay
orcid

Research Focus & Metrics

Academic Career Length

26Years (2001-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 February 2018 in Materials Research
Verified
Journal Article
Open access
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ESEduardo Braga Costa Santos
Eduardo Braga Costa Santos
CMCamila Gomes Moreno
Camila Gomes Moreno
JBJanetty Jany Pereira Barros
Janetty Jany Pereira Barros
DMDanusa Araújo de Moura
Danusa Araújo de Moura
FFFabiana de Carvalho Fim
Fabiana de Carvalho Fim
LSLucineide Balbino Silva
Lucineide Balbino Silva
The effect of alcaline and hot water surface treatments of piassava Attalea funifera fibers was investigated. The efficiency of each treatment was evaluated by Fourier transform infrared spectroscopy, X-ray diffractometry, optical microscopy, scanning electron microscopy and atomic force microscopy. The alkaline treatments were effective in removing the superficial lignin layer from the fiber, while the hot water treatment was not. Treatment with hot water and NaOH caused fiber defibrillation. NaOH was most effective in promoting both, a decrease in fiber diameter and an increase in fiber surface area. Treatment with Ca(OH)2 led to the formation of a CaCO3 layer deposited on the fiber, preventing defibrillation. The crystalline structure of the fiber was not altered by any of the treatments, maintaining type I cellulose.

1 September 2007 in Ceramics International
Verified
Journal Article
Closed access
VMV.P.B. Marques
V.P.B. Marques
ARAndreas Ries
Andreas Ries
ASA.Z. Simões
A.Z. Simões
MRMiguel Angel Ramirez
Miguel Angel Ramirez
JVJ.A. Varela
J.A. Varela
Elson LongoElson Longo
Elson Longo

1 March 2003 in Materials Characterization
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Journal Article
Closed access
ARAndreas Ries
Andreas Ries
ASA.Z. Simões
A.Z. Simões
MCM. Cilense
M. Cilense
MZM.A. Zaghete
M.A. Zaghete
JVJ.A. Varela
J.A. Varela

1 August 2006 in Materials Chemistry and Physics
Verified
Journal Article
Closed access
ASA.Z. Simões
A.Z. Simões
CQC. Quinelato
C. Quinelato
ARAndreas Ries
Andreas Ries
BSB.D. Stojanovic
B.D. Stojanovic
Elson LongoElson Longo
Elson Longo
JVJ.A. Varela
J.A. Varela

1 April 2003 in Materials Letters
Verified
Journal Article
Closed access
ASA.Z. Simões
A.Z. Simões
MZM.A. Zaghete
M.A. Zaghete
BSB.D. Stojanovic
B.D. Stojanovic
CRC. S. Riccardi
C. S. Riccardi
ARAndreas Ries
Andreas Ries
JVJ.A. Varela
J.A. Varela

13 February 2006 in Applied Physics Letters
Verified
Journal Article
Closed access
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ASA. Z. Simões
A. Z. Simões
MRMiguel Angel Ramirez
Miguel Angel Ramirez
ARAndreas Ries
Andreas Ries
JVJ. A. Varela
J. A. Varela
Elson LongoElson Longo
Elson Longo
RRR. Ramesh
R. Ramesh
CaBi4Ti4O15 (CBTi144) thin films were evaluated for use as lead-free thin-film piezoelectrics in microelectromechanical systems. The films were grown by the polymeric precursor method on (100)Pt∕Ti∕SiO2∕Si substrates. The a∕b -axis orientation of the ferroelectric film is considered to be associated with the preferred orientation of the Pt bottom electrode. The Pr and Ec were 14μC∕cm2 and 64kV∕cm , respectively, for a maximum applied field of 400kV∕cm . The domain structure was investigated by piezoresponse force microscopy. The film has a piezoelectric coefficient, d33 , equal to 60pm∕V and a current density of 0.7mA∕cm2 .