RESUMO

Una buena higiene requiere de un lugar estructuralmente placentero y la aplicación de las Buenas Practicas de manipulación (BPM). Identificar que ocurre con las BPM en un centro de elaboración de alimentos en La Habana después de una cuantiosa inversión y cuál es la opinión de los manipuladores es el propósito del trabajo. Se aplicó la guía de Evaluación Sanitaria de Hoteles, elaborada por el Ministerio de Salud Pública de Cuba determinándose los aspectos deficientes. Se encuestaron los manipuladores y se evaluó el control de las BPM. Se realizaron 2 inspecciones una inicial anterior a la reparación y una posterior, se comprobó que existió mejoría de las condiciones higiénico sanitario pero las deficiencias entrenamiento/procedimiento se mantenían en el segundo lugar lo que apunta a la falta de sensibilización de los manipuladores y la administración. Los trabajadores plantean varios factores como elementos desfavorables como la no exigencia y control, la inestabilidad de la dirección entre otros. Además realizaron propuestas como poner carteles para enfatizar conductas, reconocimiento al manipulador que cumple con las BPM, apoyo y exigencia administrativa. En este centro cuando se valoró el control de la dirección se comprobó que no era sistemático que existían pocas evidencias y no se había diseñado un plan de mejoras.(AU)

We think that a nice, shining place, which is attractive to us, assures the correct hygiene. It is indisputable that a good hygiene needs of a place structurally pleasant to our senses but that also it agree with the hygiene norms, if this exists an excellent base is created for the application of the good practices of manipulation. To identify what is happen in a center of food elaboration in Havana after a large investment and what the opinion about the manipulators is to increase the employment of the good practices of manipulation. Two examinations were realized an initial previous to the repair and a later one, it was proved that improvement of the conditions increase hygienic sanitarily but the shortcomings training / procedure were supported in the second place what points at the absence of sensitization of the manipulators and the administration. The workers raise several factors as unfavorable elements: as not demand and control, the instability of the direction between others. Also they realized proposals like putting cartels to emphasize conducts, stimulation of the out-standing manipulator, support and administrative demand. In this center when the control of the direction was valued it was proved that it was not systematical that few evidences existed and a progress plan had not been designed.(AU)

Assuntos

RESUMO

Una buena higiene requiere de un lugar estructuralmente placentero y la aplicación de las Buenas Practicas de manipulación (BPM). Identificar que ocurre con las BPM en un centro de elaboración de alimentos en La Habana después de una cuantiosa inversión y cuál es la opinión de los manipuladores es el propósito del trabajo. Se aplicó la guía de Evaluación Sanitaria de Hoteles, elaborada por el Ministerio de Salud Pública de Cuba determinándose los aspectos deficientes. Se encuestaron los manipuladores y se evaluó el control de las BPM. Se realizaron 2 inspecciones una inicial anterior a la reparación y una posterior, se comprobó que existió mejoría de las condiciones higiénico sanitario pero las deficiencias entrenamiento/procedimiento se mantenían en el segundo lugar lo que apunta a la falta de sensibilización de los manipuladores y la administración. Los trabajadores plantean varios factores como elementos desfavorables como la no exigencia y control, la inestabilidad de la dirección entre otros. Además realizaron propuestas como poner carteles para enfatizar conductas, reconocimiento al manipulador que cumple con las BPM, apoyo y exigencia administrativa. En este centro cuando se valoró el control de la dirección se comprobó que no era sistemático que existían pocas evidencias y no se había diseñado un plan de mejoras

We think that a nice, shining place, which is attractive to us, assures the correct hygiene. It is indisputable that a good hygiene needs of a place structurally pleasant to our senses but that also it agree with the hygiene norms, if this exists an excellent base is created for the application of the good practices of manipulation. To identify what is happen in a center of food elaboration in Havana after a large investment and what the opinion about the manipulators is to increase the employment of the good practices of manipulation. Two examinations were realized an initial previous to the repair and a later one, it was proved that improvement of the conditions increase hygienic sanitarily but the shortcomings training / procedure were supported in the second place what points at the absence of sensitization of the manipulators and the administration. The workers raise several factors as unfavorable elements: as not demand and control, the instability of the direction between others. Also they realized proposals like putting cartels to emphasize conducts, stimulation of the out-standing manipulator, support and administrative demand. In this center when the control of the direction was valued it was proved that it was not systematical that few evidences existed and a progress plan had not been designed

RESUMO

Una buena higiene requiere de un lugar estructuralmente placentero y la aplicación de las Buenas Practicas de manipulación (BPM). Identificar que ocurre con las BPM en un centro de elaboración de alimentos en La Habana después de una cuantiosa inversión y cuál es la opinión de los manipuladores es el propósito del trabajo. Se aplicó la guía de Evaluación Sanitaria de Hoteles, elaborada por el Ministerio de Salud Pública de Cuba determinándose los aspectos deficientes. Se encuestaron los manipuladores y se evaluó el control de las BPM. Se realizaron 2 inspecciones una inicial anterior a la reparación y una posterior, se comprobó que existió mejoría de las condiciones higiénico sanitario pero las deficiencias entrenamiento/procedimiento se mantenían en el segundo lugar lo que apunta a la falta de sensibilización de los manipuladores y la administración. Los trabajadores plantean varios factores como elementos desfavorables como la no exigencia y control, la inestabilidad de la dirección entre otros. Además realizaron propuestas como poner carteles para enfatizar conductas, reconocimiento al manipulador que cumple con las BPM, apoyo y exigencia administrativa. En este centro cuando se valoró el control de la dirección se comprobó que no era sistemático que existían pocas evidencias y no se había diseñado un plan de mejoras.

We think that a nice, shining place, which is attractive to us, assures the correct hygiene. It is indisputable that a good hygiene needs of a place structurally pleasant to our senses but that also it agree with the hygiene norms, if this exists an excellent base is created for the application of the good practices of manipulation. To identify what is happen in a center of food elaboration in Havana after a large investment and what the opinion about the manipulators is to increase the employment of the good practices of manipulation. Two examinations were realized an initial previous to the repair and a later one, it was proved that improvement of the conditions increase hygienic sanitarily but the shortcomings training / procedure were supported in the second place what points at the absence of sensitization of the manipulators and the administration. The workers raise several factors as unfavorable elements: as not demand and control, the instability of the direction between others. Also they realized proposals like putting cartels to emphasize conducts, stimulation of the out-standing manipulator, support and administrative demand. In this center when the control of the direction was valued it was proved that it was not systematical that few evidences existed and a progress plan had not been designed.

Assuntos

RESUMO

Europium doped silver tungstates α-Ag2-3xEuxWO4 (x = 0, 0.0025, 0.005, 0.0075 and 0.01 mol) were synthesized by the coprecipitation method at 90 °C for 30 minutes. These crystals were structurally characterized by means of X-ray diffraction (XRD), Rietveld refinement, and micro-Raman (MR) and Fourier transformed infrared (FT-IR) spectroscopies. Field emission scanning electron microscopy (FE-SEM) images were employed to observe the shape of the crystals. The optical properties were investigated by ultraviolet-visible (UV-vis) absorption and photoluminescence (PL) measurements. The XRD pattern indicated structural organization at a long range for all undoped and Eu-doped samples, while MR and FT-IR revealed that the presence of the Eu(3+) ions favors the structural organization at a short range. The Rietveld refinement showed that all the crystals are monophasic with an orthorhombic structure and the Pn2[combining macron]n space group. The refined lattice parameters and atomic positions were employed to model the WO6 and AgOn (n = 2, 4, 6 and 7) polyhedra in the unit cell. FE-SEM analysis revealed nanorod-like microcrystals with growth of metallic silver on the surface. Further, the UV-vis absorption spectra indicated the existence of intermediary energy levels within the band gap. PL spectra showed a broad band related to the [WO6] group and characteristic narrow peaks due to the f-f transitions of Eu(3+) as a result of efficient energy transfer from the matrix. Also, the emission line shape transitions from (5)D0 to (7)FJ (J = 0-4) levels of the Eu(3+) were noticed. Among the samples, the most intense photoluminescence results were observed for the α-Ag2-3xEuxWO4 (x = 0.0075) sample. Lifetime decays support that the Eu(3+) ions occupy at least two crystallographic sites. CIE coordinates confirmed the colors of the emission spectra which classify this material as a potential phosphor in the visible range.

RESUMO

We report on the structural, optical, and magnetic properties of α,ß-NiMoO4 nanorods synthesized by annealing the NiMoO4:nH2O precursor at 600°C for 10 minutes in a domestic microwave. The crystalline structure properties of α,ß-NiMoO4 were investigated using X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Raman (FT-Raman) spectroscopies. The particle morphologies and size distributions were identified by field emission microscopy (FE-SEM). Experimental data were obtained by magnetization measurements for different applied magnetic fields. Optical properties were analyzed by ultraviolet-visible (UV-vis) and photoluminescence (PL) measurements. Our results revealed that the oxygen atoms occupy different positions and are very disturbed in the lattice and exhibit a particular characteristic related to differences in the length of the chemical bonds (Ni-O and Mo-O) of the cluster structure or defect densities in the crystalline α,ß-NiMoO4 nanorods, which are the key to a deeper understanding of the exploitable physical and chemical properties in this study.

RESUMO

In this work, a SiO(2) spherical were prepared by the Stöber Method and then recovered with a single layer of Eu(2)O(3) oxide (SiO(2)@Eu(2)O(3)) obtained by the Polymeric Precursor Method. The SiO(2)@Eu(2)O(3) powder was heated treated at 100, 300, 400, 500 and 800 °C. The samples were characterized by the Scanning Electonic Microscopy (SEM), Thermal Analysis (TGA/DTA), and the luminescent properties of the SiO(2)@Eu(2)O(3) powders were studied by their emission and excitation spectra as well as by the lifetime measurements of the Eu(3+) (5)D(0) → (7)F(2) transition. The SEM analysis shows that the silica prepared by the Stöber Method is spherical with a particle size of 460 nm. The emission spectra of the SiO(2)@Eu(2)O(3) powders presented the Eu(3+) characteristics bands related to the (5)D(0) → (7)F(J) (J = 0, 1, 2, 3, 4) transitions at 577, 591, 616, 649 and 695 nm, respectively. The band related to the (5)D(0) → (7)F(2) transition is the most intense in the spectra, and its intensity decreases with the temperature enhancement. The decay curves of the SiO(2)@Eu(2)O(3) samples presented monoexponential features, and the obtained lifetime values were higher than the Eu(2)O(3) oxide. It was possible to conclude that the (5)D(0) → (7)F(2) hypersensitive transition is strongly dependent on the Eu(3+) surrounding.

RESUMO

BaMoO(4):Eu (BEMO) powders were synthesized by the polymeric precursor method (PPM), heat treated at 800 degrees C for 2 h in a heating rate of 5 degrees C/min and characterized by powder X-ray diffraction patterns (XRD), Fourier Transform Infra-Red (FTIR) and Raman spectroscopy, besides room temperature Photoluminescence (PL) measurements. The emission spectra of BEMO samples under excitation of 394 nm present the characteristic Eu(3+) transitions. The relative intensities of the Eu(3+) emissions increase as the concentration of this ion increases from 0.01 to 0.075 mol, but the luminescence is drastically quenched for the Ba(0.855)Eu(0.145)MoO(4) sample. The one exponential decay curves of the Eu(3+ 5)D(0)-->(7)F(2) transition, lambda (exc) = 394 nm and lambda (em) = 614 nm, provided the decay times of around 0.54 ms for all samples. It was observed a broadening of the Bragg reflections and Raman bands when the Eu(+3) concentration increases as a consequence of a more disordered material. The presence of MoO(3) and Eu(2)Mo(2)O(7) as additional phases in the BEMO samples where observed when the Eu(3+) concentration was 14.5 mol%.

RESUMO

A strong greenish-light photoluminescence (PL) emission was measured at room temperature for disordered and ordered powders of CaMoO4 prepared by the polymeric precursor method. The structural evolution from disordered to ordered powders was accompanied by XRD, Raman spectroscopy, and TEM imagery. High-level quantum mechanical calculations in the density functional framework were used to interpret the formation of the structural defects of disorder powders in terms of band diagram and density of states. Complex cluster vacancies [MoO3 x V(O(z))] and [CaO7 x V(O(z))] (where V(O(z)) = V(O(X)), V(O(*)), V(O(**))) were suggested to be responsible to the appearance of new states shallow and deeply inserted in the band gap. These defects give rise to the PL in disordered powders. The natural PL emission of ordered CaMoO4 was attributed to an intrinsic slight distortion of the [MoO4] tetrahedral in the short range.

RESUMO

Nowadays solid state chemists have the possibility of work with low temperature strategies to obtain solid state materials with appropriate physical and chemical properties for useful technological applications. Photonic core shell materials having a core and shell domains composed by a variety of compounds have been synthesized by different methods. In this work we used silica-germania soot prepared by vapor-phase axial deposition as a core where a nanoshell of Eu(2)O(3) was deposited. A new sol-gel like method was used to obtain the Eu(2)O(3) nanoshell coating the SiO(2)-GeO(2) particles, which was prepared by the polymeric precursor method. The photophysical properties of Eu(3+) were used to obtain information about the rare earth surrounding in the SiO(2)-GeO(2)@Eu(2)O(3) material during the sintering process. The sintering process was followed by the luminescence spectra of Eu(3+) and all the samples present the characteristic emission related to the (5)D(0)-->(7)F( J ) (J = 0, 1, 2, 3 and 4). The ratios of the (5)D(0)-->(7)F(2)/(5)D(0)-->(7)F(1) emission intensity for the SiO(2)-GeO(2)@Eu(2)O(3) systems were calculated and it was observed an increase in its values, indicating a low symmetry around the Eu(3+) as the temperature increases.

RESUMO

The study of the photoluminescent properties affected by order and disorder of the BaMoO(4) powders is the principal objective in this work. BaMoO(4) compounds were prepared using soft chemical process called Complex Polymerization Method. In this work, different deagglomeration types and different heating rates were used to promote different disorder degrees. Scheelite type phase (BaMoO(4)) was determined by X-ray Diffraction (XRD), Fourier Transformed Infra-Red (FTIR) and Raman spectroscopy after heat treating the sample at 400 degrees C. The room temperature luminescence spectra revealed an intense single-emission band in the visible region. Based on XRD and Raman data it was observed that the transition between the completely disordered structure to completely ordered structure is a good condition for photoluminescence (PL) emission. The best PL emission is obtained when the material possesses short range disorder, i.e., is periodically ordered (XRD), but some disorder as measured by Raman spectroscopy. The excellent optical properties observed for disordered BaMoO(4) suggested that this material is a highly promising candidate for optical applications.

RESUMO

Ultrafine PbZr0.20Ti0.80O3 was amorphized through high-energy mechanical milling. The structural evolution through the amorphization process was accompanied by various characterization techniques, such as X-ray diffraction, Fourier-transformed IR spectroscopy (FTIR), high-resolution transmission electron microscopy (HR-TEM), and Raman spectroscopy. A strong photoluminescence was measured at room temperature for amorphized PbZr0.20Ti0.80O3, and interpreted by means of high-level quantum mechanical calculations in the density functional theory framework. Three periodic models were used to represent the crystalline and amorphized PbZr0.20Ti0.80O3, and they allowed the calculation of electronic properties that are consistent with the experimental data and that explain the appearance of photoluminescence.