The Rubiaceae family in the Carrancas Mountain Complex, state of Minas Gerais, southeastern Brazil

Rubiaceae is the fourth largest family of the angiosperms in terms of species diversity worldwide. It is present in all plant physiognomies and occupies various vegetation strata, being one of the most important components of tropical vegetation. It is easily recognized by the opposite leaves, interpetiolar stipules, gamopetalous corolla, and inferior ovary. The main objective of this study was to investigate the diversity of the Rubiaceae in the Carrancas Mountain Complex, Minas Gerais, Brazil. This region encompasses approximately 17,609 km2, extending from the southern border of the state of Minas Gerais, approaching the Itatiaia Plateau, to the Sao Joao del-Rei and Barbacena region, where the Sao Francisco River basin begins. It includes the municipalities of Lavras, Itumirim, Ingaí, Itutinga, Carrancas, and Minduri. Situated in an ecotone between the Atlantic Forest and Cerrado domains, it presents a surface covered by various vegetation types, such as campo rupestre, savannas, open fields, scrublands, seasonal semideciduous forests, riparian or gallery forests, and cloud forests at the higher elevations. A total of 681 herbarium specimens were analysed, most of them deposited at the ESAL herbarium, which holds most of the collections made in the region. In this study, 26 genera and 51 species were recorded. These represent noteworthy 37.7% of the genera and 13.5% of the species of Rubiaceae recorded in Minas Gerais, including 14 endemic species to Brazil. Borreria and Palicourea were the most diverse genera (five species each), followed by Cordiera, Galianthe, and Psychotria (four species each). Therefore, this work enriches the taxonomic knowledge of the Rubiaceae family in the state of Minas Gerais, particularly for the flora of the Carrancas Mountain Complex

Determination of the magnetocaloric entropy change by field sweep using a heat flux setup

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESWe report on a simple setup using a heat flux sensor adapted to a Quantum Design Physical Property Measurement System to determine the magnetocaloric entropy change (Delta S). The major differences for the existing setups are the simplicity of this assembly and the ease to obtain the isothermal entropy change either by a field sweep or a temperature sweep process. We discuss the use of these two processes applied to Gd and Gd5Ge2Si2 samples. The results are compared to the temperature sweep measurements and they show the advantages of this setup and of the field sweep procedure. We found a significant reduction of DS and on the refrigerating cooling power (RCP) at low field changes in a field sweep process when the sample is not driven to the same initial state for each temperature. We show that the field sweep process without any measuring protocol is the only correct way to experimentally determine DS and RCP for a practical regenerative refrigerator.105715FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESSem informaçãoSem informaçãoSem informaçã

Thermal lens spectrometry to study complex fluids

We describe applications of Thermal Lens Spectrometry to study optical and thermal properties of lyotropic liquid crystal. In particular, we refer to methods for measurements of thermal diffusivity anisotropy at different temperatures and as a function of the ferrofluids doping. The theoretical basis for quantitative measurements is discussed together with the advantages and limitations as compared with conventional methods. Finally, future developments of photothermal techniques for these applications are assessed.0000Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Thermal Diffusion of a Two Layer System

In this paper thermal conductivity and thermal diffusivity of a two layer system is examined from the theoretical point of view. We use the one dimensional heat diffusion equation with the appropriate solution in each layer and boundary conditions at the interfaces to calculate the heat transport in this bounded system. We also consider the heat flux at the surface of the samle as boundary condition instead of using a fixed tempertaure. From this, we obtain an expression for the efective thermal diffusivity of the composite sample in terms of the thermal diffusivity of its constituent materials whithout any approximations.Comment: 16 pages, 1 figure, RevTeX v. 3.0 macro packag

Cs2NaAl1-xCrxF6: A family of compounds presenting magnetocaloric effect

FUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFINANCIADORA DE ESTUDOS E PROJETOS - FINEPIn this paper we explore the magnetocaloric effect (MCE) of chromium-doped elpasolite Cs2NaAl1-x,CrxF6 (x = 0.01 and 0.62) single crystals. Magnetization and heat capacity data show the magnetocaloric potentials to be comparable to those of garnets, perovskites, and other fluorides, producing magnetic entropy changes of 0.5 J/kg K (x = 0.01) and 11 J/kg K (x = 0.62), and corresponding adiabatic temperature changes of 4 and 8 K, respectively. These values are for a magnetic field change of 50 kOe at a temperature around 3 K. A clear Schottky anomaly below 10 K, which becomes more apparent when an external magnetic field is applied, was observed and related to the splitting of the Cr3+ energy levels. These results hint at a new family of materials with potential wide use in cryorefrigeration.90616FUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFINANCIADORA DE ESTUDOS E PROJETOS - FINEPSem informaçãoSem informaçãoSem informaçãoSem informaçãoSem informaçãoWe thank Pedro von Ranke (UERJ, Brazil) and Walter Kalceff (UTS, Australia) for fruitful discussions. J.C.G.T.’s participation in this work was financed by the Science without Borders Program. Access to CICECO/Chemistry Department (Aveiro, Portugal), GPMR-UNICAMP (Campinas, Brazil), LMBT- UFF (Niter´oi, Brazil), LBT-UFRJ (Rio de Janeiro, Brazil), BERII facilities, and LaMMB MagLab (Berlin, Germany) are gratefully acknowledged by all authors. Financial support was provided by Proppi/UFF, FAPERJ, FAPESP, CAPES, CNPq, and FINEP

Cs2NaAl1-xCrxF6: A family of compounds presenting magnetocaloric effect

In this paper we explore the magnetocaloric effect (MCE) of chromium-doped elpasolite Cs2NaAl1-x,CrxF6 (x = 0.01 and 0.62) single crystals. Magnetization and heat capacity data show the magnetocaloric potentials to be comparable to those of garnets, perovskites, and other fluorides, producing magnetic entropy changes of 0.5 J/kg K (x = 0.01) and 11 J/kg K (x = 0.62), and corresponding adiabatic temperature changes of 4 and 8 K, respectively. These values are for a magnetic field change of 50 kOe at a temperature around 3 K. A clear Schottky anomaly below 10 K, which becomes more apparent when an external magnetic field is applied, was observed and related to the splitting of the Cr3+ energy levels. These results hint at a new family of materials with potential wide use in cryorefrigeration

On the thermal characterization of solids by photoacoustic calorimetry: thermal diffusivity and linear thermal expansion coefficient

CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOIn this paper, we resume a straightforwardly methodology that can be employed for accurate thermal diffusivity measurement by photoacoustics. The proposed methodology involves measurements in the thermally thick sample regime with normalization using a thermally thin reference sample, as well as consideration of the sample's thermoelastic bending in both the thermally thin and thick regime. The usefulness of the method has been demonstrated with measurements in test samples of different materials. The possibilities of the method to account for linear thermal expansion coefficient have been discussed too. It has been demonstrated that for the determination of this parameter the sample must be in the ideal thermally thick regime, i.e. the range of modulation frequencies used must lie well above the cut-off frequency between the thermally thin and thick regimes. In other words, this cut-off frequency must be very small. Although this condition is very difficult to be achieved in praxis, in order to account for it, a method is proposed here that involves measurements in samples with different thicknesses and uses an extrapolation procedure.In this paper, we resume a straightforwardly methodology that can be employed for accurate thermal diffusivity measurement by photoacoustics. The proposed methodology involves measurements in the thermally thick sample regime with normalization using a thermally thin reference sample, as well as consideration of the sample's thermoelastic bending in both the thermally thin and thick regime. The usefulness of the method has been demonstrated with measurements in test samples of different materials. The possibilities of the method to account for linear thermal expansion coefficient have been discussed too. It has been demonstrated that for the determination of this parameter the sample must be in the ideal thermally thick regime, i.e. the range of modulation frequencies used must lie well above the cut-off frequency between the thermally thin and thick regimes. In other words, this cut-off frequency must be very small. Although this condition is very difficult to be achieved in praxis, in order to account for it, a method is proposed here that involves measurements in samples with different thicknesses and uses an extrapolation procedure.6145258CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOSem informaçãoAgências de fomento estrangeiras apoiaram essa pesquisa, mais informações acesse artig

Temperature Dependence Of The Refractive Index Near The Reentrant-isotropic--calamitic-nematic Phase Transition.

The laser-induced nonlinear optical response of a lyotropic liquid crystal system in the reentrant-isotropic and calamitic-nematic phases is investigated by the use of the thermal lens technique. The occurrence of an inversion in the temperature coefficient of the ordinary refractive index, dn(radially)/dT, near the reentrant-isotropic-calamitic-nematic phase transition, is discussed. This effect is attributed to the behavior of the electronic polarizability due to the change in micelle shape near the isotropic-nematic transition, and correlated with the results obtained near the nematic-isotropic transition, previously reported.6401270

In vitro determination of the sun protection factor of sunscreens through photoacoustic spectroscopy: A new approach

The investigation of the sun protection factor (SPF) and the efficacy of ultraviolet absorber ingredients are extremely important items for the cosmetic industry. The development of new efficient in vitro methodologies for these investigations is an essential condition for the evolution of sunscreens. The most accepted test for assessing the efficacy of sunscreens is the in vivo (in humans) SPF determination, following validated and worldwide adopted methodologies like those regulated by FDA (USA), COLIPA (Europe) and JCIA (Japan). However, due to the high costs and time consumption of in vivo SPF determination, the constant development of in vitro methods able to predict the in vivo SPF is very important. The present study evaluates different experimental methods for in vitro SPF determination – photoacoustic spectroscopy (PAS) and transmission spectroscopy (TS), employing different substrates (PMMA and VitroSkin®) and concentrations (0.8 mg/cm2 and 2 mg/cm2). Results are compared to the labeled SPF. The high correlation between the labeled SPF and the SPF determined by PAS expands the application of this technique in the photobiology field

Large magnetocaloric effect and refrigerant capacity near room temperature in as-cast Gd5Ge2Si2-xSnx compounds

Large values of isothermal entropy change (Delta S-T) and refrigerant capacity have been found in Gd5Ge2Si2-xSnx compounds. Values of the order of 20 J kg(-1) K-1 for -Delta S-T were obtained in as-cast samples when submitted to a magnetic field variation of 2 T. First-order-magneto-structural transition is induced by the substitution of silicon by tin and it is shifted to lower temperatures with the tin content. It means that the magnetocaloric effect on this series can be properly tuned to a specific practical thermodynamic cycle, including near room temperature range. (C) 2013 AIP Publishing LLC.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo UNIFESP, Inst Ciencia & Tecnol, BR-12231280 Sao Jose Dos Campos, SP, BrazilInst Nacl Metrol Qualidade & Tecnol INMETRO, BR-25250020 Duque de Caxias, RJ, BrazilUniv Estadual Campinas, UNICAMP, Inst Fis Gleb Wataghin, BR-13083970 Campinas, SP, BrazilUniv Fed Vales Jequitinhonha & Mucuri, ICT, BR-39100000 Diamantina, MG, BrazilUniv Estadual Norte Fluminense Darcy Ribeiro UENF, Lab Ciencias Fis, BR-28013602 Campos Dos Goytacazes, RJ, BrazilUniversidade Federal de São Paulo UNIFESP, Inst Ciencia & Tecnol, BR-12231280 Sao Jose Dos Campos, SP, BrazilWeb of Scienc