Oxidação do borneol à cânfora com água sanitária - um experimento simples, de baixo custo e limpo

Regulatory pressure is increasingly focusing on the use and disposal of substances hazardous to human health and environment. In the last years efforts have also been made to introduce green chemistry concepts in undergraduate courses. In this paper we present an experiment on the oxidation reaction of borneol to camphor with bleach in acetone. This experiment is important to show undergraduate students that a cheap and non hazardous commercial product can be a useful oxidation agent of alcohols.

Desenvolvimento e avaliação de um porta-amostra de baixo custo para caracterização elétrica de materiais cerâmicos

Conventional sample holder cells used to the electric characterization of ceramics at high temperature consists of an alumina tube and platinum wires and plates using a complex design. The high cost materials used in the conventional sampler holder cell were replaced by stainless steel and conventional ceramics. The sample holder was validated by characterizing yttria-stabilized-zirconia in a temperature range of 25 to 700 ºC. The results do not present variations, discontinuity or unusual noise in the electric signals. Several samples were characterized without maintenance, which demonstrates that the sample holder is electric and mechanic adequate to be used to electrical characterization of ceramics up to 700 ºC.

Hidróxido de níquel suportado em carbono: um catalisador de baixo custo para a eletro-oxidação de alcoóis em meio alcalino

The present manuscript shows the synthesis of nickel hydroxide supported in carbon (Ni(OH)2/C) as a alternative material for catalytic alcohol oxidation in alkaline medium. The Ni(OH)2/C was synthesized in different percentage using a sonic bath. No current densities variation during successive cyclic voltammetry experiments was observed. The Ni(OH)2/C electrodes exhibit a potent and persistent electrocatalytic activity towards the oxidation of different alcohols. In addition, alcohols electooxidation occurs in less positive potential compared with noble metal catalyst.

Construção de uma célula de gás de baixo custo para análise no infravermelho

Infrared spectroscopy is a versatile technique used for qualitative and quantitative determination of all types of molecular species. As far as analysis of confined or flowing gases is concerned, different types of cell can be found in the market, but they are often very expensive. This study describes the construction of a very efficient gas cell with good reproducibility for qualitative infrared analysis of confined or flowing gases, using easily available and low-cost materials.

Construção e aplicação de um minissensor de filme de bismuto utilizando materiais de baixo custo para determinações voltamétricas in loco

The construction of a low cost mini sensor containing a bismuth-film electrode (BiFE), as work electrode, a silver electrode as pseudo reference electrode, and copper as counter electrode is proposed. The application of this mini sensor using a low cost electrochemical cell for in loco voltammetric determinations of inorganic and organic analytes is also described.

Equipamento de baixo custo para extração em fase sólida em amostras aquosas de grande volume utilizando pressão positiva de N

Extraction/concentration is a crucial step for the analysis of organic compounds at trace level concentrations and dispersed in complex matrices. Solid-phase extraction (SPE) is one of the techniques used for this purpose. In this work, a low cost apparatus for SPE was developed that uses nitrogen under positive pressure and ensures the maintenance of the sample flow, while also allows the simultaneous extraction of different samples without cross-contamination and sample contact with plastic materials. For the system set up, easily accessible materials were used such as hypodermic needles, stainless steel tubes, rubber stoppers, and 3-way valves from serum delivery apparatus.

Aplicação da radiação ultravioleta como forma de contribuição para a química verde e construção de um reator fotoquímico alternativo e de baixo custo, para pré-tratamento de amostras

Ultraviolet radiation corresponds to a fraction of electromagnetic radiation, covering wavelengths between 1 and 400 nm. Methods based on UV irradiation have become popular because it is possible to treat samples simply by applying energy, avoiding procedures that require the use of toxic substances, thus contributing to the development of Green Chemistry. This study aimed to assess the main applications of UV radiation reported in the literature and thoroughly described the construction of an alternative and low-cost photochemical reactor to be used for the pretreatment of samples in the laboratory. The use of this new photochemical reactor in the clean-up of milk samples for spectrofluorimetric measurements was also reported.

Desenvolvimento de um sistema de análise por injeção em fluxo utilizando materiais alternativos de baixo custo para fins didáticos

This work describes a simple and inexpensive flow injection analysis system in which gravity force provides fluid propulsion while needles for insulin administration or metallic wires act as electrodes for amperometric detection. The proposed system was able to demonstrate the influence of several operational parameters on the transient signals. Moreover, this system was successfully used to evaluate both the stoichiometry of Cu2+-EDTA complex and the effect of pH on the kinetics of the reaction between ferricyanide and ascorbic acid. Therefore, the proposed system can be regarded as an efficient and accessible didactic tool for the teaching of FIA principles.

DESENVOLVIMENTO DE EXPERIMENTO DIDÁTICO DE ELETROGRAVIMETRIA DE BAIXO CUSTO UTILIZANDO PRINCÍPIOS DA QUÍMICA VERDE

In this paper, we describe the development of low-cost teaching experiments of electrogravimetry for undergraduate students using principles of green chemistry. Copper was electrochemically deposited on brass under an electrical current density of 50 mA cm−2 from acidic solutions containing nitrate anions. Color changes at the brass electrode and of the solution were observed, indicating that the reduction of copper ions had occurred. The deposition efficiency values were between 92.8% and 93.8%, and the electrochemical efficiency values were between 85.6% and 86.5%. There was no significant contribution from parallel reactions. These experimental conditions facilitated the didactic exploration of gravimetric and electrochemical concepts. Following the principles of green chemistry, the experiments produced no toxic substances, all the materials could be recycled, and the energy consumption was the lowest. For this reason, this experiment was considered to be very interesting for didactical purposes.

Venture capital investment on SME

The thesis investigates if venture capital investments affect the development of SMEs positively. The thesis will also view the presence of venture capitalists affect on the capital structure of SMEs and other company determinants in the financial crisis. The theories effecting to SME investment has been presented to provide background information. The data consist of the financial statement data and the results a corporate questionnaire. The questionnaire consists of 63 questions and 860 corporate answered the questionnaire. The result shows that venture capitalist seems to have a negative effect on SMEs productivity. Also SMEs with a venture capitalist have more negative outlook for future in the financial crisis.

Russian Venture Capital Markets

Tämän työn tarkoituksena on arvioida riskipääomasijoittamisen kehitystä ja kasvua Venäjällä, sekä antaa kuva siihen vaikuttavista tekijöistä. Se myös arvioi Venäjän valtion toimintaa niin säätelijänä, kuin myös itsenäisenä sijoittajana. Saavutetut tulokset perustuvat haastatteluihin ja olemassa olevien tilastojen analysointiin. Vuoden 1998 rupla kriisin jälkeen riskipääomasijoittaminen lähti kasvuun joka on jatkunut tasaisella rauhallisella tahdilla. Alueellisista riskipääomarahastoista on siirrytty myös yksityisrahoitteisiin ja yksityishallinnoituihin rahastoihin omine kohde aloineen ja portfolioineen. Silti markkinat ovat säilyneet kyllästymättöminä. Kuluttajavetoiset toimialat ovat keränneet eniten investointeja talouden ja ostovoiman kasvusta johtuen. Alueellisesti Moskova erottuu sijoituskohteena, muiden suurempien kasvukeskusten seuratessa perässä. Venäjällä on vielä paljon heikkouksia jotka vaikuttavat sen houkuttelevuuteen sijoittajan näkökulmasta. Heikot instituutiot ja lainsäädäntö yhdistettynä riskipääomasijoittamisen luonteeseen tekevät Venäjästä arvaamattoman markkina-alueen. Se kuitenkin tarjoaa menestyville sijoittajille korkeat tuotot. Nähtäväksi jää kuinka valtion toiminta vaikuttaa markkinoiden kehitykseen lyhyellä ja pitkällä tähtäimellä, ja kuinka se onnistuu kehittämään Venäjän yleistä kilpailukykyä globaaleilla markkinoilla.

Construção de um calorímetro de baixo custo para a determinação de entalpia de neutralização

Neste artigo descreve-se a construção de um calorímetro simples, utilizando materiais de fácil aquisição, para a determinação de entalpia de neutralização (pressão constante) de reações ácido-base. Foram utilizadas para o desenvolvimento do experimento soluções de ácidos e bases fortes e fracos, além de termômetro e recipiente de poliestireno expandido (isopor) para a medida e manutenção da temperatura, respectivamente. Com este experimento, foi então possível determinar a entalpia de neutralização (ΔH) de algumas reações de neutralização e compará-las com o valor mais aceito de - 55,84 kJ mol -1, a 25 ºC [1].

Venture capital investment on SME

This thesis studies venture capital investment on small and medium-sized enterprises (SMEs). The specific objective of the study is to test whether venture capitalists have a positive effect on SMEs. In addition effect of several other factors is studied in financial crisis. Used determinants are formulated based on three capital structure theories. The pecking order theory concerns favoring on financing source over another. The agency theory and the tradeoff theory concentrate on the search of optimal capital structure. The data of this study consist of financial statement data and results of corporate questionnaire. Regression analysis was used to find out the effects of several determinants. Regression models were formed based on the presented theories. SMEs with and without venture capitalists were considered separately. It was found that venture capitalists have a positive effect on SMEs. Although some results between SMEs with and without venture capitalists were mixed.

Characteristics of credit risk assessment methods of major Nordic banks in allocating capital when extending credits to large corporations

Credit risk assessment is an integral part of banking. Credit risk means that the return will not materialise in case the customer fails to fulfil its obligations. Thus a key component of banking is setting acceptance criteria for granting loans. Theoretical part of the study focuses on key components of credit assessment methods of Banks in the literature when extending credits to large corporations. Main component is Basel II Accord, which sets regulatory requirement for credit risk assessment methods of banks. Empirical part comprises, as primary source, analysis of major Nordic banks’ annual reports and risk management reports. As secondary source complimentary interviews were carried out with senior credit risk assessment personnel. The findings indicate that all major Nordic banks are using combination of quantitative and qualitative information in credit risk assessment model when extending credits to large corporations. The relative input of qualitative information depends on the selected approach to the credit rating, i.e. point-in-time or through-the-cycle.