This study seeks to develop and evaluate a program of selfinstructional drill materials for improving the ability of students to detect pitch errors in choral singing. The specific purposes of the study are as follows: (1) To develop and validate a visualaural test for pitch-error detection; (2) to develop a visual-aural, self-instructional program for improving the ability of students to detect pitch errors; and (3) To determine whether the program of self-instructional drill materials modifies the ability to detect pitch errors. In the first phase of this three-phase study, a body of testing materials was assembled, pilot-tested, edited, and judged reliable for use. In Phase II a body of self-instructional, programmed drill materials was assembled, pilot-tested, corrected, and judged ready for evaluation. In Phase III the procedures were as follows: (1) the subjects for whom the program was intended were administered a pretest of their pitch-error detection ability; (2) one group (A) participated in the programmed drill materials developed, while the other group (B) used no programmed materials; (3) both groups were administered a midtest to determine whether there was any change; (4) the latter group (B) participated in the programed drill materials developed, while the first group (A) no longer used the programmed materials; (5) students in both groups were administered a posttest to deterine the effectiveness of the programmed drill materials in developing the ability to detect pitch errors while reading the vocal score.

The title of the thesis is forbidden means and ways of conducting armed conflicts. Obviously, this topic is too broad, so thesis is focused on the issue of chemical and biological weapons. These devices are among the weapons of mass destruction and undoubtedly pose one of the major dangers of the contemporary world. The overall goal of this work is to provide perspective on the issue of chemical and biological weapons from a historical perspective and particularly from a perspective of the international law. International legal documents are viewed in historical and political context. Through this analysis of international treaties, we can "effectively" consider their impacts and responses in a "real world". The first part of the thesis serves as a historical introduction with some interesting chapters from early history of chemical and biological weapons. The second part deals with the birth of these weapons in a new and modern form in the 19th century. Great attention is paid to the period of the World War I. It was in this global conflict in which chemical weapons were used in their modern form and in the most massive form at the same time. In next chapters, this thesis examines how chemical and biological weapons and their international legal regulation evolved during the 20th century,...

Master of Music / Department of Music / Frank Tracz / The following report provides a comprehensive analysis of two works for wind band and one small chamber work for woodwind octet: Night Dances for Wind Ensemble by Bruce Yurko, Octet in E-flat Major, Op. 103 by Ludwig van Beethoven, and Simple Gifts: Four Shaker Songs by Frank Ticheli. This analysis provides information necessary for a conductor’s rehearsal preparation. Included is biographical information about the composer and a historical perspective of the composition itself. Highlighted are the technical difficulties, stylistic concerns, musical elements, and form and structure of each composition. As the researcher, my music education mission statement and perspective on quality literature selection are also included. Suggested listening, seating charts, acoustical justifications, and rehearsal plans with researcher evaluations are provided. The compilation of this information will allow conductors to make more informed musical decisions during their preparation and performances of the works.

Development of synthetic routes toward two general organometallic frameworks was undertaken. The first project involved synthetic attempts of substituted and unsubstituted ferroceno[c]thiophene while the second one was the synthesis of 1,2-dithienylmetallocenes. The long-term goal of this work is to lay the foundations for study of electronic, electrochromic, redox, and optical properties of thiophene-based materials integrated with organometallic systems such as ferrocene, ruthenocene and cymantrene. The synthetic pathway for the target molecule in the first project involved converting 1,2-bis(hydroxymethyl)ferrocene to 1,2-bis(thiouroniummethyl)ferrocene with thiourea under acidic conditions. Refluxing the salt in base followed by acidification resulted in 1,2-bis(mercaptomethyl)ferrocene, which is oxidized to the cyclic ferroceno[d]-1,2-dithiane. Ring contraction of cyclic dithiane gave the thioether, ferroceno[c]-2,5-dihydrothiophene. Periodate oxidation of the thioether gave ferroceno[c]-2,5-dihydrothiophene-S-oxide (1), a potential precursor for ferroceno[c]thiophene via Pummerer dehydration. Attempts to dehydrate 1 and to trap the resulting thiophene in situ indicated instability of the target compound. Synthesis of ferroceno[c]thiophene with electron-donating as well as electron-withdrawing substituents at the 2,5-positions of the thiophene ring was attempted. 1,2–Dithienylethenes and their derivatives have gained increased attention due to their exceptional photochromic property. They tend to be thermally irreversible but photochemically reversible, which is a vital for their potential use in optical memories, switches and other optoelectronic applications. Inspiration of the second project was that incorporation of 1,2-dithienyl systems into metallocenes would enhance the general properties of the molecule, including stability, fatigue resistance, solid-state reactivity and higher sensitivity. 1,2-Dithienylferrocene was successfully synthesized. The synthetic pathway for 1,2-dithienylferrocene involved the reaction of α-bromo-3-acetyl-2,5-dimethylthiophene (1) with ethyl 4-(2,5-dimethylthiophen-3-yl)-3-oxobutanoate (2) to give 2,3-diarylcyclopent-2-en-1-one (3). Compounds 1 and 2 were synthesized following literature methods. Compound 3 was then converted to its cyclopentadienide form by first reducing the ketone to alcohol using LAH, followed by dehydration and then deprotonation of the substituted cyclic diene using butyllithium to give 1,2-bis(2,5-dimethylthiophene)-2,4-cyclopentadien-1-yl)lithium (4). [Fe(fluorenyl)(Cp)] was then used as a transfer reagent and reacted with 4 to yield the target compound.

Neste trabalho, serão apresentados o comportamento eletroquímico e espectro-eletroquímico dos polímeros condutores poli(sulfeto de fenileno fenilenamina) (PPSA) e poli(anilina) (PANI) no líquido iônico bis(trifluorometanosulfonil)imideto de 1-butil-2,3-dimetilimidazólio (BMMITFSI). Os experimentos eletroquímicos em BMMITFSI mostram que o PPSA apresenta dois processos redox reversíveis sem sinais de perda de eletroatividade e mostram também a obtenção da PANI pela polimerização eletroquímica da anilina com os dois processos redox típicos das transformações em leucoesmeraldina ↔ esmeraldina ↔ pernigranilina, sem a necessidade de adição de ácidos e sem nenhum sinal de degradação em potenciais elevados. Os experimentos de UV-Vis e Raman Ressonante evidenciaram a estabilização das estruturas oxidadas formadas em líquido iônico tornando este fato a principal razão para o comportamento reversível dos processos redox de ambos os polímeros. Os experimentos de resistência in situ da PANI, demonstraram que a pernigranilina obtida em potenciais elevados é mantida na forma condutora. Estes fenômenos observados em ambos os polímeros indicam que a alta atmosfera iônica do BMMITFSI, estaria estabilizando as estruturas mais oxidadas (dicátions) em potenciais elevados, o que evita a degradação e perda de eletroatividade do PPSA e permite a condutividade da PANI na forma pernigranilina sal. / In this work, the electrochemical and spectroelectrochemical behavior of Poly(phenylenesulfide phenyleneamine) (PPSA) and polyaniline (PANI) conducting polymers in a room temperature ionic liquids, 1-butyl-2-3-dimethylimidazolium bis(trifluorometanessulfonil)imide (BMMITFSI) is presented. Electrochemical experiments of a PPSA in BMMITFSI show two reversible redox processes without loss of electroactivity. Aniline polymerization to obtain PANI films with typically two redox processes due to leucoemeraldine ↔ esmeraldine ↔ pernigraniline transformations was also carried out in the absence of acids, and even cycling till high positive potentials, no degradation signals were observed. UV-Vis and Resonance Raman studies show the stabilization of dications in BMMITFSI as the main reason to the reversible redox behavior observed on both conducting polymers and the in-situ resistance measurements corroborated the stabilization of pernigraniline salt at high oxidation potentials in the conducting form of PANI. These results obtained in room temperature ionic liquid shows that the high ionic medium given by the BMMITFSI would shield the positive charges, which would stabilize the dication species at high potentials, avoiding the degradation and loss of electroaticity of PPSA and allowing charge transport on pernigraniline salt.

Among the organic electronic conducting organic polymers PEDOT (poly(3,4- ethylenedioxythiophene)) is largely used in the making of electrodes for miniaturized, light and portable devices. The chemical, mechanical, electrochemical and optical properties of the conducting polymers are essential to plan the future research with them, as in, e.g., electrochromic devices (transmissive and reflective), chronoamperometric sensors, voltammetric sensors and controlled drug release systems. Degradability is also an important factor considering the environmental impact of the materials. Nanoparticles (NPs) of Au or Pt (1−100 nm size), when surrounded by a stabilizer, are stable, have reactive and functionalizable surfaces and catalyze many electron transfer reactions. Combinations of noble metal nanoparticles with PEDOTs (PEDOT and its derivatives) have been studied in the last years to obtain singular characteristics of the materials. The goals of this work are to study the synthesis of new inorganic/organic hybrids and their electrochemical behavior. Through 1-step oxidoreduction reaction in aqueous media, hybrids of core-shell Au@PEDOT nanoparticles were synthesized. Through this same strategy, nanoparticles of Pt dispersed in a matrix of PEDOT were synthesized. The Au@PEDOT nanoparticles had their electrochromic behavior studied. With the biodegradable macromonomer EDOTpoly(lactic acid) (EDOT-PLA) were prepared hybrids of NPsAu/(oligomers of EDOTPLA) and also of NPsAu with the new polymer PEDOT-PLA. The produced materials were analyzed. The nanoparticles are very small, with a maximum of distribution in less than 10 nm. Its observed that PEDOT-PLA is conducting, electronically similar to PEDOT and insoluble in water. It is also more stable as a film than PEDOT. NPsAu/PEDOT-PLA demonstrates to have electrocatalytic towards the reduction of hydrogen peroxide. Electrodes of high performance towards the reduction of hydrogen peroxide were thus obtained (sensitivity 8.4x10-3 A cm-2 mol-1 L; linear range (5.1x10-4 − 4.5x10-2) mol L-1; limit of detection 1.7x10-4 mol L-1). Syntheses of acrylic hydrogels and the insertion of nanoparticles/PEDOT in them were also performed, modifying their properties. / Entre os polímeros orgânicos condutores eletrônicos o PEDOT (poli(3,4- etilenodioxitiofeno)) é largamente utilizado na fabricação de eletrodos em dispositivos miniaturizados, leves e portáteis. As propriedades químicas, mecânicas, eletroquímicas e ópticas dos polímeros condutores são essenciais para planejar a pesquisa futura com eles, e.g., em dispositivos eletrocrômicos transmissivos e reflexivos, sensores cronoamperométricos, sensores voltamétricos e sistemas de liberação controlada de drogas. Degradabilidade também é um fator importante ao considerar o impacto ambiental dos materiais. Nanopartículas (NPs) de Au ou Pt (1−100 nm de tamanho), quando revestidas por um estabilizante, são estáveis, possuem superfícies reativas e funcionalizáveis e catalisam muitas reações de transferência de elétrons. As combinações de nanopartículas de metais nobres com PEDOTs (PEDOT e seus derivados) vêm sendo bastante estudadas nos últimos anos de forma a obter características singulares dos materiais. Os objetivos deste trabalho são estudar a síntese de novos híbridos inorgânicos/orgânicos e o seu comportamento eletroquímico. Foram sintetizados, por reação de oxidorredução em uma etapa em meio aquoso, híbridos de nanopartículas core-shell de Au@PEDOT. Por esta mesma estratégia, nanopartículas de Pt dispersas em matrizes de PEDOT foram sintetizadas. As nanopartículas de Au@PEDOT tiveram o seu comportamento eletrocrômico estudado. Com o macromonômero biodegradável EDOT-poli(ácido lático) (EDOT-PLA) foram preparados híbridos de NPsAu/(oligômeros de EDOT-PLA) e também de NPsAu com o novo polímero PEDOT-PLA. Os materiais produzidos foram analisados. As nanopartículas são muito pequenas, com um máximo de distribuição em menos de 10 nm. Observa-se que o PEDOT-PLA é um condutor, de estrutura eletrônica semelhante ao PEDOT e insolúvel em água. Ele também é mais estável em filme do que o PEDOT. NPsAu/PEDOT-PLA demonstra ter atividade eletrocatalítica de redução do peróxido de hidrogênio. Eletrodos de alto desempenho para a redução de peróxido de hidrogênio foram, portanto, obtidos (sensibilidade 8,4x10-3 A cm-2 mol-1 L; faixa linear (5,1x10-4 4,5x10-2) mol L-1; limite de detecção 1,7x10-4 mol L-1). Foram feitas também sínteses de hidrogeis acrílicos e a inserção de nanopartículas/PEDOT neles, modificando as suas propriedades.

Esta tese versa sobre a caracterização espectroscópica de materiais híbridos orgânico-inorgânicos de polianilina (PANI), um polímero condutor, e hexaniobato, um óxido semicondutor. Os materiais híbridos foram preparados por diferentes rotas, empregando-se nanopartículas de hexaniobato esfoliado (nanofolhas ou nanoscrolls), e PANI previamente preparada (rotas ex-situ), ou através da polimerização da anilina na presença do hexaniobato (rotas in-situ). As principais técnicas de caracterização utilizadas foram as espectroscopias Raman ressonante (RR) e de ressonância paramagnética eletrônica (EPR), microscopia eletrônica de varredura (SEM) e análise termogravimétrica acoplada a espectrometria de massas (TGA-MS). No entanto, outras técnicas como espectroscopias eletrônica no UV-VIS-NIR e vibracional no infravermelho, e difratometria de raios X foram muito importantes para complementar a caracterização e suportar os resultados. Observou-se que a PANI pode ser adsorvida sobre os nanoscrolls de hexaniobato através de diferentes rotas de preparação, como por montagem de filmes layer-by-layer, mistura das dispersões dos componentes, ou polimerização in-situ da anilina na presença das nanopartículas de hexaniobato. De acordo com os dados espectroscópicos, estas morfologias favorecem maiores graus de dopagem (protonação) do polímero em relação à polianilina pura (ou prístina), associados a fortes interações entre a polianilina e o hexaniobato, que apresenta alta acidez superficial. Os dados espectroscópicos revelaram que a deslocalização eletrônica dos pólarons e as populações relativas dos pólarons e bipólarons da polianilina são afetadas na presença do hexaniobato, indicando que a interação entre os componentes também pode induzir mudanças conformacionais das cadeias poliméricas. Através da espectroscopia RR empregando diferentes radiações excitantes, foi possível identificar os segmentos cromofóricos formados durante a oligo/polimerização da anilina em meios de diferentes pHs, distintos do empregado na síntese convencional da polianilina (ácido clorídrico 1 mol L-1). O produto majoritário é constituído de unidades 1,4-benzoquinona-monoimina acopladas a unidades aminofenil, compondo estruturas complexas denominadas \"adutos de anilina\". Além destas estruturas, a espectroscopia RR possibilitou a identificação de segmentos tipo-fenazina e segmentos polarônicos da PANI como produtos minoritários. Quando a reação é realizada na presença de hexaniobato, ainda há formação majoritária de adutos de anilina, mas há formação de maiores quantidades de segmentos polarônicos da polianilina. Estes resultados foram associados à alta acidez superficial do hexaniobato, mostrando novamente a importância do componente inorgânico para a estrutura dos materiais híbridos. Os estudos das propriedades eletrocrômicas dos filmes híbridos layer-by-layer apresentaram acentuada variação de coloração em diferentes regiões do espectro visível e eficiência eletrocrômica superior às dos filmes constituídos por hexaniobato ou PANI, indicando a características promissoras para utilização desses filmes híbridos em dispositivos eletrocrômicos. A melhoria das propriedades térmicas dos materiais híbridos foi comprovada pelos dados de TGA-MS e espectroscopia Raman, que mostraram claramente que a PANI na presença do hexaniobato permanece dopada após tratamento térmico (150 °C por 90 min), enquanto que polímero prístino sofre desdopagem. Estas características são consideradas importantes para o desenvolvimento de dispositivos que envolvam processamento térmico dos materiais. / This thesis presents spectroscopic characterization of organic-inorganic hybrid materials of polyaniline (PANI), a conducting polymer, and hexaniobate, a semiconducting metal oxide. The hybrid materials were prepared by different routes, which used nanoparticles of exfoliated hexaniobate (nanosheets or nanoscrolls), and PANI previously prepared (ex-situ routes), or by aniline polymerization in the presence of hexaniobate (in-situ routes). The main characterization techniques were resonance Raman (RR) and electron paramagnetic resonance (EPR) spectroscopies, scanning electron microscopy (SEM) and mass spectrometry coupled-thermogravimetric analysis (TGA-MS). However, other techniques such as electronic UV-VIS-NIR and vibrational infrared spectroscopies, and X-ray diffractometry were also employed to support the characterization and results. Scanning electron microscopy showed that PANI is adsorbed on the hexaniobate nanoscrolls in the hybrid materials prepared by different routes, such as layer-by-layer assembly, mixture of dispersions of the components, or in-situ polymerization of aniline in the presence of the hexaniobate nanoparticles. According to spectroscopic data, such morphologies promote higher doping degrees (protonation) of the polymer comparing with pure PANI (pristine PANI), associated to strong interactions between PANI and hexaniobate, which presents high acidic surfaces. The spectroscopic data also revealed that the electronic delocalization of the polaronic segments, and the relative populations of polarons and bipolarons are affected in the presence of hexaniobate, indicating that the interactions between the components may also induce conformational changes on the polymeric chains. By RR spectroscopy using different exciting radiations, it was possible to identify the chromophoric segments produced during aniline oligo/polymerization in media of different pHs than that used in conventional procedures for preparation of PANI (hydrochloric acid, 1 mol L-1). It was shown that the major product is 1,4-benzoquinone-monoimine moieties coupled to aminophenyl moieties, resulting in complex structures named aniline adducts. Moreover, RR spectroscopy was very useful for the identification of phenazine-type segments and polaron segments as minor reaction products. When aniline-APS reactions are performed in the presence of hexaniobate, \"aniline adducts\" are also the major products, but RR spectra showed that there is higher formation of polaron segments of PANI. Such results were associated to the high acidic surface of hexaniobate, showing once again the important role of the inorganic component to determine the structure of the hybrid materials. The investigation on the electrochromic properties of the layer-by-layer hybrid films showed intense color variation at different regions of the visible spectrum, and higher electrochromic efficiencies comparing with the films composed but only hexaniobate or PANI, indicating the promising features for development of electrochromic devices. The improvement of thermal properties of the hybrid materials was verified by TGA-MS data and Raman spectra, which clearly showed that PANI in the presence of hexaniobate remains in the doped form after thermal treatment (150 °C for 90 min), while the pristine polymer undergoes a dedoping process. These features are considered important for the development of devices which depend on the thermal processing of the materials.

Este trabalho está estruturado a partir de três diferentes e concomitantes frentes de pesquisa (cujos suportes metodológicos são discutidos na Introdução) e traz uma abordagem diversificada acerca da Regência coral infantojuvenil. Parte-se de uma pesquisa social com 52 regentes que, em suas respostas ao questionário apresentado, identificam características, desafios e dificuldades de ordem social e técnica no desenvolvimento de seus grupos e nos oferecem dados sobre o atual contexto em que a atividade coral é realizada. Com a análise desses dados, foram eleitos três focos de pesquisa bibliográfica, referentes às principais questões colocadas pelos regentes: a própria Regência, a Técnica Vocal e a Educação Musical. Assim, foram levantados pontos de vista de variados autores referentes a esses itens,que tradicionalmente fazem parte da formação do regente e compõem o conjunto de saberes, competências e habilidades desse profissional. Segue-se uma discussão sobre elementos estruturais dos coros e sobre os aspectos de um planejamento em canto coral, visando facilitar e organizar as tarefas do regente, especialmente no que concerne aos procedimentos de ensaio e aos processos de criação e recriação na música coral. A pesquisa-ação foi realizada a partir doPCIU! (Projeto Coral Infantojuvenil da Universidade Federal de Mato Grosso do Sul), um grupo coral infantojuvenil criado especificamente para os fins desta pesquisa, que perpassa toda a discussão e sintetiza o todo, na medida em que se observa o desenvolvimento do coro e se analisam as atividades e escolhas técnicaspresentes nos ensaios. As dificuldades relatadas pelos colegas regentes corais participantes da pesquisa servem de pano de fundo permanente ao processo reflexivo e interagem com as práticas do PCIU!, em uma pesquisa coesa que une teoria e prática e se consolida em um trabalho artístico de performance musical. / This work is structured from three different and concomitant research fronts (whose methodological supports are discussed in the Introduction) and brings a diverse approach to the Children\'s and youth\'s choir conducting. It begins from a social survey with 52 conductors; in their responses to the questionnaire presented, they identify features, challenges and difficulties of social and technical order in the development of their groups and provide us data about the current context in which the choral activity is fulfilled. By analyzing these data, we elected three focuses of literature research, about the main issues raised by conductors: the Conducting itself, Vocal Technique and Music Education. Thus there were raised points of view of various authors regarding these items, which traditionally are part of the conductor\'s formation and consist the set of knowledge, skills and abilities of this professional. Then follows a discussion about structural elements and planning in choral singing, aiming to facilitate and organize the conductor\'s tasks, especially what regards to the processes of choral rehearsal and the processes of creation and recreation in choral music. The action research was accomplished from the PCIU! (Children and Youth Choir Project of the Federal University of Mato Grosso do Sul), a children\'s and youth group created specifically for the purposes of this research, which permeates the whole discussion and summarizes the whole, accordingly it observes the development of the choir, and it analyzes the activities and technical choices present in rehearsals. The difficulties reported by fellow conductors participants of the research serve as a permanent backdrop to the reflective process and interact with the PCIU! practices, into a cohesive research that combines theory and practice and is consolidated into an artistic work of musical performance.

To design an efficient solar energy conversion device, theoretical input is extremely important to provide the basic guideline for experimental scientists, to fabricate the most efficient, cheap, and stable device with less efforts. This desire can be made possible if computational scientist use a proper theoretical protocol, design an energy material, then the experimentalist will only invest weeks or months on the synthetic effort. This thesis highlights my recent efforts in this direction. Monoclinic BiVO4 is has been using as a photocatalyst due to its stability, cheap, easily synthesizable, narrow band gap and ideal VB (-6.80 eV vs vacuum) but inappropriate CB (-4.56 eV vs vacuum) edge position, responsible for its low efficiency. We have carried out a comprehensive experimental and periodic density functional theory (DFT) simulations of the pristine, Oxygen defective (Ov), Se doped monoclinic BiVO4 and heterojunction with Selenium (Se-BiVO4), to improve not only its CB edge position but photocatalytic and charge carrier properties. It is found that Ov (1% Oxygen vacancy) and mild doped BiVO4 (1 to 2% Se) are thermodynamically stable, have ideal band edges ~ -4.30 eV), band gaps (~1.96 eV), and small effective masses of electrons and holes. We have also investigated the contribution of Se to higher performance by effecting morphology, light absorption and charge transfer properties in heterojunction. Finally, it is found that Se makes a direct Z-scheme (band alignments) with BiVO4 where the photoexcited electron of BiVO4 recombine with the VB of Se, consequences electron-hole separation at Se and BiVO4, respectively, as a result, enhanced photocurrent is obtained. Theoretical study of β-TaON in the form of primitive unit cell, supercell and its N, Ta, and O terminated surfaces are carried out with the help of periodic DFT. Optical and electronic properties of all these different species are simulated, which predict TaON as the best candidate for photocatalytic water splitting contrast to their Ta2O5 and Ta3N5 counterparts. The calculated bandgap, valence band, and conduction band edge positions predict that β-TaON should be an efficient photoanodic material. The valence band is made up of N 2p orbitals with a minor contribution from O 2p, while the conduction band is made up of Ta 5d. Turning to thin films, the valence band maximum; VBM (−6.4 eV vs. vacuum) and the conduction band minimum; CBM (−3.3 eV vs. vacuum) of (010)-O terminated surface are respectively well below and above the redox potentials of water as required for photocatalysis. Charge carriers have smaller effective masses than in the (001)-N terminated film (VBM −5.8 and CBM −3.7 eV vs. vacuum). However, due to wide band gap (3.0 eV) of (010)-O terminated surface, it cannot absorb visible wavelengths. On the other hand, the (001)-N terminated TaON thin film has a smaller band gap in the visible region (2.1 eV) but the bands are not aligned to the redox potential of water. Possibly a mixed phase material would produce an efficient photoanode for solar water splitting, where one phase performs the oxidation and the other reduction. Computational study of an optically transparent, near-infrared-absorbing low energy gap conjugated polymer, donor−acceptor−donor (D-A-D) with promising attributes for photovoltaic application is reported herein. The D and A moiety on the polymeric backbone have been found to be responsible for tuning the band gap, optical gap, open circuit (Voc) and short-circuit current density (Jsc) in the polymers solar cells (PSC). Reduction in the band gap, high charge transformation, and enhanced visible light absorption in the D-A-D system is because of strong overlapping of molecular orbitals of D and A. In addition, the enhanced planarity and weak steric hindrance between adjacent units of D-A-D, resulted in red-shifting of its onset of absorption. Finally, PSC properties of the designed D-A-D was modeled in the bulk heterojunction solar cell, which gives theoretical Voc of about 1.02 eV. DFT study has been carried out to design a new All-Solid-State dye-sensitized solar cell (SDSC), by applying a donor-acceptor conjugated polymer instead of liquid electrolyte. The typical redox mediator (I1−/I3−) is replaced with a narrow band gap, hole transporting material (HTM). A unique “upstairs” like band energy diagram is created by packing N3 between HTM and TiO2. Our theoretical simulations prove that the proposed configuration will be highly efficient as the HOMO level of HTM is 1.19 eV above the HOMO of sanitizer (dye); providing an efficient pathway for charge transfer. High short-circuit current density and power conversion efficiency is promised from the strong overlapping of molecular orbitals of HTM and sensitizer. A low reorganization energy of 0.21 eV and exciton binding energy of 0.55 eV, confirm the high efficiency of HTM. Theoretical and experimental studies of a series of four porphyrin-furan dyads were designed and synthesized, having anchoring groups, either at meso-phenyl or pyrrole-β position of a zinc porphyrin based on donor–π–acceptor (D–π–A) approach. The porphyrin macrocycle acts as donor, furan hetero cycle acts as π-spacer and either cyanoacetic acid or malonic acid group acts as acceptor. Optical bandgap, natural bonding, and molecular bonding orbital (HOMO–LUMO) analysis confirm the high efficiency pyrrole-β substituted zinc porphyrins contrast to meso-phenyl dyads. DFT study of polypyrrole-TiO2 composites has been carried out to explore their optical, electronic and charge transfer properties for the development of an efficient photocatalyst. Titanium dioxide (Ti16O32) was interacted with a range of pyrrole (Py) oligomers to predict the optimum composition of nPy-TiO2 composite with suitable band structure for efficient photocatalytic properties. The study has revealed that Py-Ti16O32 composites have narrow band gap and better visible light absorption capability compared to individual constituents. A red-shifting in λmax, narrowing band gap, and strong intermolecular interaction energy (-41 to −72 kcal/mol) of nPy-Ti16O32 composites confirm the existence of strong covalent type interactions. Electron−hole transferring phenomena are simulated with natural bonding orbital analysis where Py oligomers found as donor and Ti16O32 as an acceptor in nPy-Ti16O32 composites. Sensitivity and selectivity of polypyrrole (PPy) towards NH3, CO2 and CO have been studied at DFT. PPy oligomers are used both, in the doped (PPy+) and neutral (PPy) form, for their sensing abilities to realize the best state for gas sensing. Interaction energies and amount of charges (NBO and Mulliken charge analysis) are simulated which reveal the sensing ability of PPy towards these gases. PPy, both in doped and neutral state, is more sensitive to NH3 compared to CO2 and CO. More interestingly, NH3 causes doping of PPy and de-doping of PPy+, providing evidence that PPy/PPy+ is an excellent sensor for NH3 gas. UV-vis and UV-vis-near-IR spectra of nPy, nPy+, and nPy/nPy+-X complexes demonstrate strong interaction of PPy/PPy+ with these atmospheric gases. The applications of graphene (GR) and its derivatives in the field of composite materials for solar energy conversion, energy storage, environment purification and biosensor applications have been reviewed. The vast coverage of advancements in environmental applications of GR-based materials for photocatalytic degradation of organic pollutants, gas sensing and removal of heavy metal ions is presented. Additionally, the presences of graphene composites in the bio-sensing field have been also discussed in this review.

Nos últimos anos, vem crescendo o interesse em investigar o fenômeno da magnetorresistência em diversos materiais (inorgânicos ou orgânicos), uma vez que esse fenômeno se encontra diretamente ligado à fabricação de discos rígidos com elevada capacidade de armazenamento de dados. Estudos anteriores mostraram que o polímero PDO14FV apresenta magnetorresistência de intensidade superior as apresentadas por materiais inorgânicos. Sendo assim, o presente trabalho pretendeu desenvolver a síntese e caracterização de dois oligômeros, o dímero (DO14FV-dim) e o trímero (DO14FV-trim), e investigar o fenômeno da magnetorresistência nesses materiais. Surpreendentemente, esses oligômeros apresentaram magnetorresistência superior àquela obtida com o polímero correspondente. Esses resultados poderão contribuir, em trabalhos futuros, na elucidação do mecanismo desse fenômeno em materiais orgânicos. A síntese dos oligômeros foi feita por reação de Wittig, obtendo-se moléculas de estrutura bem definida e com configuração trans, sendo caracterizadas por métodos espectroscópicos. Visando outras aplicações, os oligômeros e o polímero foram estudados em sensores de gases, na diferenciação entre tipos e marcas de chá. Foi observado que quanto maior é a molécula, maior é seletividade, e, portanto, o polímero foi quem apresentou os melhores resultados. / There is a growing interest in investigating the phenomenon of magnetoresistance in various materials (both organic and inorganic), since it is directly linked to the manufacture of high capacity hard disk drives. Previous studies showed that the polymer PDO14FV presents magnetoresistance with higher intensity than inorganic materials. Therefore, this work consisted in the synthesis and characterization of two oligomers, the dimer (DO14FV-dim) and trimer (DO14FV-trim), of this polymer and the investigation of magnetoresistance in these materials. Surprisingly, these oligomers presented higher magnetoresistance than that exhibited by the polymer. These results may contribute in future works aiming the elucidation of the mechanism of this phenomenon in organic materials. The synthesis of the oligomers was performed by Wittig reaction. Molecules of well defined structure and trans configuration were obtained and characterized by spectroscopic methods. Aiming other applications, the oligomers and polymer were tested in gas sensors, for the discrimination between different types and brands of tea. It was observed that the greater the molecule, the greater the selectivity, and therefore, the polymer gave the best results.