TEDE Coleção:
https://tedebc.ufma.br/jspui/handle/tede/tede/881
2024-03-29T08:19:26ZDesenvolvimento de filmes biopoliméricos reforçados com material híbrido a base de haloysita e pontos poliméricos de carbono
https://tedebc.ufma.br/jspui/handle/tede/tede/5205
Título: Desenvolvimento de filmes biopoliméricos reforçados com material híbrido a base de haloysita e pontos poliméricos de carbono
Autor: ARAUJO, Rebecca Jemima Pereira
Primeiro orientador: ALCÂNTARA, Ana Clécia Santos de
Abstract: Carbon polymer dots (CPDs) are a novel type of carbon-based fluorescent (0D) nanomaterial with a
size smaller than 20 nm. Due to their unique properties, CPDs hold potential applications in various
fields of interest, such as optics, electronics, sensors and biomedicine. On the other hand, inorganic
solids, such as clay minerals have the potential for integration with various species and form
composites with low toxicity, increased biocompatibility and enhance mechanical stability. Within this
perspective, clay minerals can be combined with polymers, being processed into films. In this study, a
mixture of alginate and carboxymethylcellulose polysaccharides was incorporated with different
concentrations of a hybrid material developed from the union of the clay mineral halloysite and CPD
(HC) obtained by dry and wet processes (HC-VS and HC-VU), to form reinforced biodegradable films
(ACHC-VS and ACHC-VU). The materials were characterized by various physicochemical techniques
(FTIR, UV-Vis, XRD, DSC, BET, SEM, EDS, PL), and their barrier, optical, textural and mechanical
properties were investigated. Through UV-Vis spectroscopy, XRD, FTIR, and BET analyses, it was
observed that the HC-VS material exhibited a higher CPD content in its final composition compared
to the HC-VU material. Thus, the structural and morphological properties of ACHC-VS and ACHC-
VU films showed significant differences. The FTIR spectra of the ACHC-VS films indicated strong
hydrogen bonds between the material components, while the introduction of the HC-VS hybrids into
the biopolymeric matrix significantly blocked a substantial part of the ultraviolet radiation due to the
ability of the CPDs to absorb ultraviolet radiation and blue photons. In addition to the good mechanical
properties, the water vapor transmission rate of the resulting films showed an almost 2-fold decrease
in the composite films compared to the pure polymer film, indicating that the addition of the HC-VS
hybrid improved the barrier properties against water vapor. These results were corroborated when the
0.06 ACHC-VS film demonstrated excellent perfomance when applied as a UV blocker on bananas
and as packaging for strawberries.
Instituição: Universidade Federal do Maranhão
Tipo do documento: Dissertação2024-02-28T00:00:00ZSensor eletroquímico à base de carbon black super-P e ftalocianina de cobalto para detecção de L-cisteína
https://tedebc.ufma.br/jspui/handle/tede/tede/5153
Título: Sensor eletroquímico à base de carbon black super-P e ftalocianina de cobalto para detecção de L-cisteína
Autor: MOUCHREK, Charbel Nagib
Primeiro orientador: SILVA, Iranaldo Santos da
Abstract: In this work, was produced a novel composite material using carbon black and cobalt
phthalocyanine (CoPc/CBSP). Characterizations by spectroscopic techniques (Raman
and infrared), scanning electron microscopy, and X-ray diffraction confirmed the
formation of the composite material. This material was anchored on the glassy carbon
electrode surface, and its electrochemical sensing properties was checked using cysteine
(CYS), an important amino widely used in medicine, food additives, and cosmetics, as a
model molecule. Preliminary studies by cyclic voltammetry revealed that the modified
electrode caused considerable electrocatalytic effects (detection at potential close to 0 V)
and an increase in peak current (12-fold) compared to the unmodified electrode. When
coupled to the BIA analysis system with amperometric detection, a wide linear range (1
‒ 150 μmol L−1
) and adequate detectability (LOD = 0.133 μmol L−1
) were achieved.
Repeatability tests (n = 20) at two concentration levels (20 and 40 μmol L−1
) confirmed
the precision of the method (RSD < 11%). To evaluate the reproducibility of sensor
preparation, four different electrodes were tested against a 40 μmol L−1 concentration
solution and produced an error of 13.5%. The proposed method was applied for the
determination of CYS in pharmaceutical samples, where addition/recovery studies
(values between 89 and 110%), as well as results statistically similar to those achieved by
capillary electrophoresis, indicated the accuracy and reliability of the electrochemical
analyses.
Instituição: Universidade Federal do Maranhão
Tipo do documento: Dissertação2023-09-15T00:00:00ZNanohíbridos de manganês e enxofre: melhora de propriedades redox para aumento da capacidade de armazenamento de energia
https://tedebc.ufma.br/jspui/handle/tede/tede/5000
Título: Nanohíbridos de manganês e enxofre: melhora de propriedades redox para aumento da capacidade de armazenamento de energia
Autor: FERREIRA , Raissa Soares Penha
Primeiro orientador: GARCIA, Marco Aurélio Suller
Abstract: This work aims to develop a simple and effective methodology for synthesizing 1D
nanomaterials (nanowires) of manganese oxides that will serve as a template for forming
nanohybrids with sulfur. The central idea is to produce cheap and stable materials for applications
in pseudo-supercapacitors. As these devices aim to store a large number of electrical charges,
accumulating an internal imbalance of charges, materials with controlled size, shape, and
composition can be used to modulate the efficiency of the devices. The results obtained so far
show, through microscopy, that the nanowires were successfully obtained and that although
structural modifications occurred after sulfur insertion, the longitudinal aspect, important for
charge-discharge applications, was maintained. In addition, some indications show that the
materials incorporated sulfur in their structure. The best electrode was the 70% MnO2-S due to
the high electrochemical activity and capacitance values, which were 807.5, 655, 560, 495, 440,
and 425 F g-1
at current densities of 1, 2, 4, 6, 8, and 10 A g-1
. Still, the electrode retained 52.63%
of the initial capacitance, which is a promising result for the area
Instituição: Universidade Federal do Maranhão
Tipo do documento: Dissertação2023-09-15T00:00:00ZA ideologia da humanização e o projeto ético-político do serviço sociaL: tendências e perspectivas no trabalho do assistente social no Hospital Universitário da Universidade Federal do Maranhão (HUUFMA)
https://tedebc.ufma.br/jspui/handle/tede/tede/4998
Título: A ideologia da humanização e o projeto ético-político do serviço sociaL: tendências e perspectivas no trabalho do assistente social no Hospital Universitário da Universidade Federal do Maranhão (HUUFMA)
Autor: RODRIGUES, Suene da Silva
Primeiro orientador: LIMA, Cristiana Costa
Abstract: The National Humanization Policy (PNH) was approved in the first government of Luís
Inácio Lula da Silva, in 2003, after a review of the former National Program for
Humanization and Hospital Care (PNHAH) and has as one of its objectives the change
of culture of care in health services. The implementation of the PNH, a cross-cutting
policy to the Unified Health System (SUS), would aim to bring greater quality in health
and improvement in care that would become more humanized. By analyzing the
humanization policy beyond its appearance, it can be identified that an ideology of
humanization is present in it, highlighting characteristics such as a-historicism,
emphasis on subjective issues, focus on communication and superficiality when
dealing with the problems faced by public health. Its documents lack articulation with
the political, economic and social aspects of the country. There is the presence of an
"ingrained romanticism" with the proposal of humanizing the relationships established
in the capitalist system, which at its core carries dehumanization. The PNH is aligned
with the proposals of the Neoliberal Project for Health of privatization, outsourcing,
underfunding of the sector in addition to proposing the de-responsibility of the State.
There is also its articulation with the institutionalization of new management models in
the SUS. The Social Service, a profession that makes up the technical health team, is
also part of the professional staff that works directly with the humanization proposals
both through the Humanization Working Group (GTH) and in their daily care. The
Ethical-Political Project (PEP) of Social Work is based on Marxist thought and has
among its principles freedom and human emancipation in addition to overcoming the
current societal project. In addition, the Ethical-Political Project also aligns with the
proposals of the Health Reform Project in affirming health as a right and duty of the
State. The conception of humanization present in Marxism has work as a central
category in the process of transformation of the human being into a social being.
However, capitalism changes the nature of work making it an element of
dehumanization through alienation. Using the method of dialectical historical
materialism, we sought to understand through the articulation between field,
documentary and bibliographic research how social workers apprehend the PNH. The
theoretical-ideological bases on which the PNH (aligned with the neoliberal project and
postmodern thought) and the PEP (aligned with Marxism) were built are differentiated,
which reflects the definition of humanization present in both. It was noticed that the
issues that permeate humanization end up being dissolved amid the alienating daily
life and the immediate care of the professionals. Although there are criticisms of the
PNH, they do not point to the essence of relevant issues and problematize its
intentions. There is a departure from the perspective of humanization as proposed by
Marxism, the basis of the PEP. Although the need for appropriation of the Ethical Political Project is recognized, there is no internalization of its principles, which leaves
gaps for other conceptions to have space and to be reproduced, such as the ideology
of humanization.
Instituição: Universidade Federal do Maranhão
Tipo do documento: Dissertação2023-09-06T00:00:00Z