Accurate measurements of ammonia, nitric acid and formic acid are important for achieving a complete understanding of their atmospheric role. Models and measurements of formic acid in the atmosphere continue to show disagreements. Also, the contributions of NMHCs and reactive nitrogen (HNO3 and NH3) to organic and inorganic aerosol formation are important to quantify as gaps in the knowledge of atmospheric aerosols are a source of uncertainty in climate science. In this thesis, concentrations of ammonia were measured in the atmosphere and the production of formic acid from the ozonolysis of isoprene was measured in the EXTRA (EXTreme RAnge) chamber. Both gases were studied using chemical ionisation mass spectrometry (CIMS). The kinetics of the reactions of sesquiterpenes and terminal alkenes with ozone were studied in theEXTRA chamber using the relative rates technique and GC-FID. The ozonolysis rate coefficients of a homologous series of terminal alkenes were measured at elevated temperatures and found to be invariant with the carbon number. This led to the conclusion that previous measurements of these rate coefficients were subject to experimental artefacts. The elevated temperature protocol was employed to study the ozonolysis of sesquiterpenes, leading to revisions in ko3 for β-caryophyllene and α-humulene of 3 orders of magnitude. It was thus concluded that ozonolysis only accounts for 9-15% of sesquiterpeneoxidation in the atmosphere. A field intercomparison of CIMS for measuring ammonia was conducted wherein CIMS was found to perform well alongside instruments of comparable time response and limits of detection. This thesis also characterised inlet materials used in atmospheric measurements in the first systematic study on the uptake onto inlet walls in a flow tube system coupled to CIMS. It was found that PFA is the preferable material for atmospheric measurements, both for its kinetic qualities and its ready availability and ease of use. Finally, CIMS was used to measure the yield of formic acid from isoprene ozonolysis as a function of relative humidity. Formic acid yield was found to increase between 0-40% RH to a maximum of 0.18. Using the measured formic acid yields in a global chemistry model leads to an estimate that formic acid production from isoprene ozonolysis is ~9.5 Tg yr-1.

In recent years, nanostructured materials incorporated with inorganic particles and polymers have attracted attention for simultaneous multifunctional biomedical applications. This thesis summarized three works, which are preparation of mesoporous silica coated superparamagnetic iron oxide (Fe3O4@mSiO2) nanoparticles (NPs) as magnetic resonance imaging T2 contrast agents, polymer grafted Fe3O4@mSiO2 NPs response to temperature change, synthesis and biocompatibility evaluation of high aspect ratio (AR) gold nanorods. Monodisperse Fe3O4@mSiO2 NPs have been prepared through a sol-gel process. The coating thickness and particle sizes can be precisely controlled by varying the synthesis parameters. Impact of surface coatings on magnetometric and relaxometric properties of Fe3O4 NPs is studied. The efficiency of these contrast agents, evaluated by MR relaxivities ratio (r2/r1), is much higher than that of the commercial ones. This coating-thickness dependent relaxation behavior is explained due to the effects of mSiO2 coatings on water exclusion. Multifunctional core-shell composite NPs have been developed by growing thermo-sensitive poly(N-isopropylacrylamide-co-acrylamide) (P(NIPAAm-co-AAm)) on Fe3O4@mSiO2 NPs through free radical polymerization. Their phase transition behavior is studied, and their lower critical solution temperature (LCST) can be subtly tuned from ca. 34 to ca. 42 °C, suitable for further in vivo applications. A seedless surfactant-mediated protocol has been applied for synthesis of high AR gold nanorods with the additive of HNO3. A growth mechanism based on the effect of nitrate ions on surfactant micelle elongation and Ostwald ripening process is proposed. The biocompatibility of high AR nanorods was evaluated on primary human monocyte derived dendritic cells (MDDCs). Their minor effects on viability and immune regulatory markers support further development for medical applications. / QC 20110701

<p dir="ltr">Since before the Apollo era, the rocket propulsion sector has been a key player in developing standards of cleanliness and compatibility when designing, building, and operating systems with toxic propellants. The advent of hypergols and the widespread use of propellants like N₂O₄, Mixed Oxides of Nitrogen (MON), and hydrazine have forced new standards to be developed to meet the ever-growing need for safety when working with dangerous substances. These systems have only continued to grow more complex and many propellant combinations remain toxic and corrosive to most substances as the industry seeks the optimal methods for deriving the most efficient, highest performing, and generally more capable. ASTM International and other standards organizations carry on documenting standards for cleaning and passivation to ensure safe use today to meet the needs of the ever-expanding propulsion industry.</p><p dir="ltr">This thesis aims to determine the feasibility of using Raman spectroscopy as a method of characterizing interactions between metals and propellants. First, a background of knowledge regarding the spectroscopic method, propellants, and industry practices was researched and current areas of possible application were identified. The passivation and propellant storage phases of system lifecycles were determined to be the scope and target for experimentation. A multilevel passivation study consisting of exposing three metal types to different concentrations of nitric acid for various durations was conducted to begin developing a greater understanding of the applicability of and the techniques required to make Raman spectroscopy work as a complement to the ASTM passivation verification tests. Lessons learned from this and a short-duration compatibility study with MON and similar metal samples were documented and will be used for a larger scale and longer duration compatibility study in conjunction with NASA White Sands Test Facility (WSTF). The buildup of safe and adequate facilities for such a study was undertaken, completed, and documented in this work.</p><p dir="ltr">The results of testing in this thesis suggest the promising and desirable non-destructive and minimally invasive features of Raman spectroscopy have the potential to be used extensively in the propulsion sector. Suggestions for developing key techniques and methods for this application are developed and outlined as they were learned throughout the study's conduction.</p>

No description available.

Objective: Twenty-two million Americans or roughly 8% of the population are hearing impaired. This affects more than just the ability for one to hear. In the last three decades, younger Americans have shown a sharp increase in hearing impairment. Hearing loss affects social and emotional well being and thus has the ability to decrease one's quality of life. This study was designed to examine the association between smoking, workplace chemical exposure, and hearing loss.Methods: This cross-sectional population-based study was conducted in an occupational health clinic setting in Virginia. The study population consisted of employees from local businesses who visited the clinic during the period of 1/1/03 to 1/1/05 for pure tone audiometry. Chart reviews supplemented by telephone interviews were conducted to extract data for analysis. All study subjects were eligible to participate except for those who were unable to communicate due to a language barrier. Prevalence and crude prevalence ratios were calculated. Adjusted prevalence ratios and prevalence odds ratios were calculated using Cox and logistic regression models. Data entry and statistical analysis were accomplished with the SPSS Data Builder and the SPSS 13.0 statistical software. SAS statistical software was also used for a portion of the statistical analysis.Results: In a Cox regression model controlling for many potential confounding factors (age, race, smoking, chemical exposure, military service, as well as others) cigarette smoking was not associated with hearing loss PR(95% CI), 1.0 (0.7, 1.3). Similarly, exposure to chemicals was not associated with hearing loss 1.1 (0.7, 1.6).Conclusion: This study did not find an association between cigarette smoking and hearing loss and exposure to industrial chemicals and hearing loss in persons who worked in a noisy occupational environment.

O processo Humifert é uma alternativa para produção de compostos fertilizantes fosfatados, com solubilização mais lenta do que os fertilizantes tradicionais, resultando em um tempo de nutrição da planta maior. No processo, utilizam-se rochas fosfáticas com algum tipo de limitação para o aproveitamento normal, seja pelos teores menores, seja por dificuldades de tratamento industrial dos minérios, além de materiais orgânicos. O objetivo deste trabalho foi melhorar o equipamento existente no Instituto de Geociências, para tornar possível condições de produção de NOx, no Processo Humifert, capaz de produzir um teor de fósforo disponibilizado em condições controladas de processo. Empregando-se planejamento estatístico de experimentos foi possível selecionar as variáveis de entrada mais importantes ao processo (agitação da mistura de rocha fosfática, matéria orgânica e umidade, A codificada; temperatura de oxidação da amônia, B codificada; umidade da mistura, C codificada; porosidade da placa difusora, D codificada; vazão do ar auxiliar, E codificada). A análise estatística, também, permitiu construir modelos de regressão nos quais as influências das variáveis de processo foram sentidas na solubilidade do fósforo nos extratores: ácido cítrico, solução 2% (Pácido cítrico); água, (Págua); citrato neutro de amônio mais água, (PCNA+água). Estas últimas variáveis aqui denominadas de variáveis de saída ou de resposta. A manipulação dos referidos modelos permite obter o fertilizante de acordo com as necessidades da cultura e do solo. O estudo, também, permitiu concluir que a maior quantidade de fósforo disponível nos compostos organofosfatados foi o solúvel em ácido cítrico, portanto, a maior quantidade de compostos gerados encontra-se na melhor condição de disponibilidade pela planta. / Humiphert process is an alternative used for producing phosphated compound fertilizers with a slower solubilization when compared to other traditional fertilizers, resulting in a longer period of plant nutrition. During the process, phosphatic rocks are used along with some sort of limitation according to the normal development, both by their lower content percentage and by treatment of difficulties of industrial ores, besides organic materials. This work aim to improve an equipment existing at the Instituto de Geociências in order to find out the best process condition to produce NOX in Humifert process. This way, the process is able to produce an available phosphorus content under process conditions controlled. The process variables were select by using of experimental design. These variables were: agitation of phosphatic rock mixture (rock, organic material and humidity), A coded; ammonia oxidation temperature, B coded; humidity of mixture, C coded; porosity of the diffusing board, D coded; auxiliary air, E coded. Statistical analysis also allowed to build regression models in which the influences of process variables were felt in the solubility of phosphorus in the extractors: 2% solution of citric acid (Pacid Citric), water (Pwater); ammonium neutral citrate plus water (PCNA + water). These last variables here called output variable or response. The manipulation of these models allows to obtain the fertilizer according to the needs of the crop and soil. The study still conclude that the greater amount of available phosphorus in compound was soluble in citric acid, therefore, a greater amount of compounds generated is in the best condition of availability for the plant. The study still conclude that the greater amount of available phosphorus in the organophosphated compounds were soluble in citric acid. Therefore, the greater amount of compounds generated is in the best condition of availability for the plant.

Bio-refining of renewable resources such as waste biomass into value added products has increased rapidly over the last decades. The aim is to find new environmentally friendly yet economically feasible ways of replacing current utilization of non renewable resources. It can be expected that a commercially viable next generation bio-ethanol will be produced from lignocellulosic feedstock in the near future.This master thesis set out to look at a specific Canadian company in depth (Pure Lignin Environmental Technology Ltd), known as PLET henceforth. PLET has a new approach in pre-treatment of biomass, with a recently patented environmentally friendly technology, which could be extremely lucrative if applied in the right context. It is desirable to look at the possibility of using the master thesis as a take-off platform to launch a consulting bio-tech company directly after completion.There are several different ways to process biomass into higher value added products. In this master thesis focus is laid upon biomass waste, but the same principles could be applied on biomass processing in general. That is the separation and purification of products. In order to put the technology of PLET into a context, other company approaches are used as a comparison, such as SEKAB E-Technology, Lignoboost and Borregaard Lignotech.It is however hard to find suitable examples equivalent to the PLET approach since the technology of PLET considers all the three constituents of wood as raw material for production of three stand alone commercial products; pure lignin, pure cellulose and hemi-cellulose. These three products are separated and purified in the pre-treatment process at high yield and practically no formation of by-products. Process parameters are only moderately adjusted depending on what raw material is used.The catalytic reactor process (=CRP), is performed by PLET as a pre-treatment in a continuous and batch system, in which lignocellulosic material (= wood chips, saw dust or other waste biomass) undergo acid catalyzed hydrolysis by dilute nitric acid. The impregnated wood chips are partially depolymerised from the lignin matrix when heated in the low pressure catalytic reactor. After that, follows distillation, condensation and almost complete recovery of dilute nitric acid. After CRP, the cellulose pulp is separated from the black liquor by an alkaline solution (=NaOH). The obtained black liquor is pumped to a separation tank to precipitate lignin and sweet liquor through filtration. The final step is to dry the lignin, while the sweet liquor is utilized by Torula yeast (=Candida utilis) in order to produce unicellular protein.It would be interesting to see if the pre-treatment that PLET provides, could be exploited in a context of production of next generation of cellulosic ethanol from the cellulosic part of waste biomass. In this master thesis, an evaluation of producing next generation ethanol from dilute-nitric acid pre-treated cellulose rich softwood was performed and dilute sulphuric acid pre-treated hemi-cellulose rich hardwood birch pulp was used as a comparison.The technical part of this master thesis was conducted on a laboratory scale, using samples from two companies, referred to as PLET and SEKAB E-technology (Sweden). The strategy of PLET is currently to find a commercial platform to produce value added products from waste biomass generated by saw mills and pulping industries, while SEKAB E-Technology mainly works with Swedish softwood as a raw material.ivExperiments of this master thesis includes a series of fermentation trials using either SSF (= Simultaneous Saccharification and Fermentation) or SHF (= Separate Hydrolysis and Fermentation). Yields of the enzymatic hydrolysis and subsequent fermentations were estimated with HPLC measurements complemented with dry weight measurements.Obtained experimental data support the potential to make lignocellulosic ethanol out of either softwood or hardwood. Ethanol yield from dry material from SEKAB E-Technology hardwood birch slurry was 0.43 (g ethanol / g dry raw material), whereas samples supplied by PLET achieved the following results. The ethanol yield from dry material from softwood pine washed cellulose was 0.33 g (ethanol / g cellulose). The ethanol yield from dry material obtained for softwood pine unwashed cellulose in the three SHF was 0.47; 0.34 and 0.19 (g ethanol / g cellulose) respectively, while the yield in the two SSF was 0.45 and 0.46 (g ethanol / g glucose).The economical part of this master thesis includes the use of Business Model Canvas and the NABC- model (= Need, Approach, Benefit and Competition) to define the basic topics and tasks that need to be addressed in the start up phase of a small consulting bio-tech company.At least 6 million US dollars is needed as a minimum starting capital to be able to construct a small commercially viable pilot plant, according to PLET. This investment would cover the basic requirements and is scalable. The construction could preferably be done in Sweden in the vicinity of an existing saw mill or paper pulp industry or elsewhere, where a steady supply of cheap raw material could be assured. The size of the operation envisioned, depends greatly on location and adjacent businesses. Large pulp mills in the range of 400-500 MWh would be preferred, the largest pulp mills in Canada process 5000 ton per day which is equivalent to a capacity of 1 GW wood per day (GW = giga watt), but the concept of the technology of PLET must first prove its value on a smaller scale.According to PLET, a future full scale production plant could be designed for processing 56 tons of wood chips per day of wood chips would generate annual revenues of ≈ 7500000 US dollars. The annual profit would be ≈ 2500000 US dollars, and capital cost (equipments) ≈ 5000000 US dollars, while the payback time on investment would be 2-3 years. According to PLET, the products are estimated to have the following values; 25 tons/day of pure cellulose with a market value of 400-500 US dollars/ton, 10 tons/day of pure lignin with a market value of 1000-1200 US dollars/ton and finally 21 tons/day of sweet liquor with a market value of 50-100 US dollars/ton. / Program: Masterutbildning i Energi- och materialåtervinning - industriell bioteknik

O processo Humifert é uma alternativa para produção de compostos fertilizantes fosfatados, com solubilização mais lenta do que os fertilizantes tradicionais, resultando em um tempo de nutrição da planta maior. No processo, utilizam-se rochas fosfáticas com algum tipo de limitação para o aproveitamento normal, seja pelos teores menores, seja por dificuldades de tratamento industrial dos minérios, além de materiais orgânicos. O objetivo deste trabalho foi melhorar o equipamento existente no Instituto de Geociências, para tornar possível condições de produção de NOx, no Processo Humifert, capaz de produzir um teor de fósforo disponibilizado em condições controladas de processo. Empregando-se planejamento estatístico de experimentos foi possível selecionar as variáveis de entrada mais importantes ao processo (agitação da mistura de rocha fosfática, matéria orgânica e umidade, A codificada; temperatura de oxidação da amônia, B codificada; umidade da mistura, C codificada; porosidade da placa difusora, D codificada; vazão do ar auxiliar, E codificada). A análise estatística, também, permitiu construir modelos de regressão nos quais as influências das variáveis de processo foram sentidas na solubilidade do fósforo nos extratores: ácido cítrico, solução 2% (Pácido cítrico); água, (Págua); citrato neutro de amônio mais água, (PCNA+água). Estas últimas variáveis aqui denominadas de variáveis de saída ou de resposta. A manipulação dos referidos modelos permite obter o fertilizante de acordo com as necessidades da cultura e do solo. O estudo, também, permitiu concluir que a maior quantidade de fósforo disponível nos compostos organofosfatados foi o solúvel em ácido cítrico, portanto, a maior quantidade de compostos gerados encontra-se na melhor condição de disponibilidade pela planta. / Humiphert process is an alternative used for producing phosphated compound fertilizers with a slower solubilization when compared to other traditional fertilizers, resulting in a longer period of plant nutrition. During the process, phosphatic rocks are used along with some sort of limitation according to the normal development, both by their lower content percentage and by treatment of difficulties of industrial ores, besides organic materials. This work aim to improve an equipment existing at the Instituto de Geociências in order to find out the best process condition to produce NOX in Humifert process. This way, the process is able to produce an available phosphorus content under process conditions controlled. The process variables were select by using of experimental design. These variables were: agitation of phosphatic rock mixture (rock, organic material and humidity), A coded; ammonia oxidation temperature, B coded; humidity of mixture, C coded; porosity of the diffusing board, D coded; auxiliary air, E coded. Statistical analysis also allowed to build regression models in which the influences of process variables were felt in the solubility of phosphorus in the extractors: 2% solution of citric acid (Pacid Citric), water (Pwater); ammonium neutral citrate plus water (PCNA + water). These last variables here called output variable or response. The manipulation of these models allows to obtain the fertilizer according to the needs of the crop and soil. The study still conclude that the greater amount of available phosphorus in compound was soluble in citric acid, therefore, a greater amount of compounds generated is in the best condition of availability for the plant. The study still conclude that the greater amount of available phosphorus in the organophosphated compounds were soluble in citric acid. Therefore, the greater amount of compounds generated is in the best condition of availability for the plant.

Neptunium, with its rich redox chemistry, has a special position in the chemistry of actinides. With a decades-long history of development of aqueous separation methods for used nuclear fuel (UNF), management of neptunium remains an unresolved issue because of its not clearly defined redox speciation. Neptunium is present in two, pentavalent (V) and hexavalent (VI) oxidation states, both in their dioxocation O=Np=O neptunyl form, which differ greatly in their solvent extraction behavior. While the neptunium(VI) dioxocation is being very well extracted, the dioxocation of pentavalent neptunium is practically non-extractable by an organic solvent. As a result, neptunium is not well separated and remains distributed in both organic and aqueous extraction phases. The aim of this study was to develop or enhance the understanding of several key topics governing the redox behavior of neptunium in nitric acid medium, which are of vital importance for the engineering design of industrial-scale liquid-liquid separation systems. In this work, reactions of neptunium(V) and (VI) with vanadium(V) and acetohydroxamic acid - two redox agents envisioned for adjusting the neptunium oxidation state in aqueous separations ��� were studied in order to determine their kinetic characteristics, rate laws and rate constants, as a function of temperature and nitric acid concentration. Further were analyzed the interactions of neptunium(V) and (VI) with nitrous acid, which is formed as a product of radiolytic degradation of nitric acid caused by high levels of radioactivity present in such systems. Once HNO��� is distributed between both the aqueous solutions and organic solvent, nitrous acid is also formed in both phases and has a key influence on redox speciation of neptunium; therefore, the effects of gamma-radiation on the redox speciation of neptunium were investigated. The work also includes the results of examination of scavenging of nitrous acid by hydrogen peroxide, which is generated along with nitrous acid during radiolysis of aqueous solutions of nitric acid, and also by chemical reactions with added scavenging agents (methylurea, acetohydroxamic acid). / Graduation date: 2013

SILVA, Katiane Pereira da. Propriedades estruturais e eletrônicas do cristal L-fenilalanina ácido nítrico e estudo vibracional sob condições extremas de pressão e temperatura. 2014. 119 f. Tese (Doutorado em Física) - Programa de Pós-Graduação em Física, Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2014. / Submitted by Edvander Pires (edvanderpires@gmail.com) on 2015-04-10T21:12:54Z No. of bitstreams: 1 2014_tese_kpsilva.pdf: 5357878 bytes, checksum: 251018043a6c9107f6c8d1df9df190fd (MD5) / Approved for entry into archive by Edvander Pires(edvanderpires@gmail.com) on 2015-04-10T21:13:24Z (GMT) No. of bitstreams: 1 2014_tese_kpsilva.pdf: 5357878 bytes, checksum: 251018043a6c9107f6c8d1df9df190fd (MD5) / Made available in DSpace on 2015-04-10T21:13:24Z (GMT). No. of bitstreams: 1 2014_tese_kpsilva.pdf: 5357878 bytes, checksum: 251018043a6c9107f6c8d1df9df190fd (MD5) Previous issue date: 2014 / The L-phenylalanine is an essential amino acid that takes part of several bio chemicals processes related to the production of some human proteins and enzymes. This essential amino acid is converted into the L-tyrosine amino acid by means of the L-phenylalanine hydroxilase. Amino acids are interesting materials for non linear optics (NLO) applications as they contain a proton donor carboxylic acid (COOH) group and a proton acceptor amine (NH2) group. In the present work, a systematic investigation has been carried out on L-phenylalanine nitric acid [C9H11NO2.C9H11NO2+.NO3-] (LPN) single crystal obtained by slow evaporation at room temperature. This work shows studies performed in a pure atomistic way by computation simulation, on the electronic and optical properties, using method of density functional theory. The crystal was characterized by single crystal X-ray diffraction, Fourier Transform infrared (FT-IR) and Fourier Transform Raman (FT-Raman) analysis. The results of the X-ray diffraction data were analyzed by the Rietveld method. Single crystal data refinement of the LPN crystal shows that this compound grows with a monoclinic structure belonging to the P21 space group with two molecules per unit cell. The calculated lattice parameter is in good agreement with the experimental results. The Mulliken and Hirschfield charges show the zwiterrionic state of the LPN crystal in the DFT converged crystals. The band gap of LPN crystal is indirect and its energy is ~3.55 eV. The 2p orbitals are the largest contributors to the density of states, suggesting that the crystal behaves like an n-type wide gap insulator. We have characterized the LPN crystal at room temperature by means of the FT-IR in the spectral range between 400 cm-1 to 4000 cm-1 and by means of FT-Raman in the spectral range between 50 cm-1 to 3500 cm-1. There was no Raman band observed in the spectral interval between 1700 cm-1 to 2700 cm-1. For wavenumber greater than 3100 cm-1, there was no Raman band. In the range between 2850 cm-1and 3100 cm-1, it observed stretching modes associated with C-H and C-H2 units. Finally, single-crystal samples of LPN were studied by Raman spectroscopy in a diamond-anvil cell up to pressures of ~ 8.0 GPa. From the analysis of the results we observed that the crystal undergoes a phase transition at about 0.6 GPa. The transition is accompanied by the disappearance of a phonon in the external mode region of the spectrum and by changes of both the wavenumber of NH3+ rocking and CH2 rocking vibrations. / A L-fenilalanina é um aminoácido essencial que participa de diversos processos bioquímicos relacionados à constituição de diversas proteínas e enzimas do corpo humano. Este aminoácido essencial através da enzima L-fenilalanina hidroxilase, é convertido no aminoácido L-tirosina. Os aminoácidos são materiais interessantes para aplicações ópticas não lineares (ONL) uma vez que contêm um próton doador do grupo carboxílico (COOH) e um próton receptor do grupo amina (NH2). No presente trabalho, uma investigação sistemática foi realizada para o cristal de L-fenilalanina ácido nítrico [C9H11NO2.C9H11NO2+.NO3-] (LFN) obtido pelo método de evaporação lenta à temperatura ambiente. Neste trabalho, estudamos de forma inteiramente atomística através de simulação computacional as propriedades eletrônicas e ópticas utilizando o método da teoria do funcional da densidade. O cristal foi caracterizado por difração de raios-X, pelas técnicas vibracionais de Transformada de Fourier no infravermelho (FT-IR) e no Raman (FT-Raman). Os resultados de difração de raios-X foram analisados pelo método de Rietveld. Os resultados do refinamento para o cristal LFN mostram que este composto cristaliza-se na estrutura monoclínica pertecente ao grupo especial P21 com duas moléculas por célula unitária. Os parâmetros de rede calculados apresentaram boa concordância com os resultados experimentais. As cargas Mulliken e Hirschfield mostram que o estado zwitteriônico do cristal LFN estão bem convergidas. A energia do gap do cristal LFN (indireto) é aproximadamente 3,55 eV. Os orbitais 2p são os maiores contribuintes para a densidade de estados, o que sugere que o cristal se comporta como um isolante. Apresentamos resultados de caracterização do cristal de LFN à temperatura ambiente, através das técnicas utilizadas de espectroscopia de absorção por transformada de Fourier na região do infravermelho (FT-IR) no intervalo espectral entre 400 cm-1 e 4000 cm-1 e espectroscopia Raman por transformada de Fourier (FT-Raman) no intervalo espectral entre 50 cm-1 e 3500 cm-1. Nenhuma banda Raman foi observada no intervalo espectral entre 1700 cm-1 e 2700 cm-1. Para o intervalo acima de 3100 cm-1 nenhuma banda Raman foi observada, o que garante que o cristal tratado está na forma anidra. Destaca-se, por exemplo, a região entre 2850 cm-1 e 3100 cm-1, onde é esperado serem observados modos vibracionais do tipo estiramento das ligações C-H e do CH2. Finalmente, para o cristal de LFN foram investigados por espectroscopia Raman em uma célula do tipo bigorna de diamantes desde a pressão ambiente até ~ 8,0 GPa. Nas análises dos resultados de altas pressões observamos que o cristal sofre uma transição de fase em torno 0,6 GPa. A transição é acompanhada pelo desaparecimento de um fônon na região dos modos externos do espectro Raman e por alterações das bandas eferentes a vibrações do tipo rocking do NH3+ e CH2.