Alphanumeric LCD infrared control via computer’s parallel port

The present work will explain a method to achieve a remote controlled (via IR LED) alphanumeric Liquid Crystal Display. In modern times, the remote access of different devices has become quite popular, therefore, the aim of this project is to provide a useful tool that will integrate common and easy to access devices. The system includes a C language based user interface, an assembly language code for the AT89C51ED2 microcontroller instructions and some digital electronic circuits needed for the driving and control of both the LCD and the infrared communication, as well as the PC with a parallel port. The interaction of all the devices provides a whole system that can be helpful in different applications, or it can be separated into each one of its different stages to take the best advantage as possible.

Influência do uso de combustíveis alternativos na síntese por combustão via microondas para a produção de materiais cerâmicos com estrutura espinélio

The development and study of detectors sensitive to flammable combustible and toxic gases at low cost is a crucial technology challenge to enable marketable versions to the market in general. Solid state sensors are attractive for commercial purposes by the strength and lifetime, because it isn t consumed in the reaction with the gas. In parallel, the use of synthesis techniques more viable for the applicability on an industrial scale are more attractive to produce commercial products. In this context ceramics with spinel structure were obtained by microwave-assisted combustion for application to flammable fuel gas detectors. Additionally, alternatives organic-reducers were employed to study the influence of those in the synthesis process and the differences in performance and properties of the powders obtained. The organic- reducers were characterized by Thermogravimetry (TG) and Derivative Thermogravimetry (DTG). After synthesis, the samples were heat treated and characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), analysis by specific area by BET Method and Scanning Electron Microscopy (SEM). Quantification of phases and structural parameters were carried through Rietveld method. The methodology was effective to obtain Ni-Mn mixed oxides. The fuels influenced in obtaining spinel phase and morphology of the samples, however samples calcined at 950 °C there is just the spinel phase in the material regardless of the organic-reducer. Therefore, differences in performance are expected in technological applications when sample equal in phase but with different morphologies are tested

Use of near-infrared Raman spectroscopy to detect IgG and IgM antibodies against Toxoplasma gondii in serum samples of domestic cats

Near-infrared Raman spectroscopy (NIRS) is a particularly promising technique that is being used in recent years for many biomedical applications. Optical spectroscopy has gained increasing prominence as a tool for quantitative analysis of biological samples, clinical diagnostic, concentration measurements of blood metabolites and therapeutic drugs, and analysis of the chemical composition of human tissues. Toxoplasmosis is an important zoonosis in public health, and domestic cats are the most important transmitters of the disease. This disease can be detected by several serological tests, which usually have a high cost and require a long time. The goal of this work was to investigate a new method to diagnosis Toxoplasma gondii infections using NIRS. In order to confirm antibody detection, 24 cat blood scrum samples were analyzed by the Raman spectra, from which 23 presented positive serology to toxoplasmosis and one was a reference negative serum. Characteristic Raman peaks allowed differentiation between negative and positive sera, confirming the possibility of antibody detection by Raman spectroscopy. These results give the first evidence that this technique can be useful to quantify antibodies in cat sera.

Deriving the magnitude of niobium off-center displacement in ferroelectric niobates from infrared spectroscopy

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influência de fotoperíodo artificial no comportamento de um primata neotropical diurno (Callithrix jacchus)

One of the main environmental cues for the adjustment of temporal organization of the animals is the light-dark cycle (LD), which undergoes changes in phase duration throughout the seasons. Photoperiod signaling by melatonin in mammals allows behavioral changes along the year, as in the activity-rest cycle, in mood states and in cognitive performance. The aim of this study was to investigate if common marmoset (Callithrix jacchus) exhibits behavioral changes under short and long photoperiods in a 24h cycle, assessing their individual behaviors, vocal repertoire, exploratory activity (EA), recognition memory (RM) and the circadian rhythm of locomotor activity (CRA). Eight adult marmosets were exposed to a light-dark cycle of 12:12; LD 08:16; LD 12:12 and LD 16:08, sequentially, for four weeks in each condition. Locomotor activity was recorded 24h/day by passive infrared motion detectors above the individual cages. A video camera system was programmed to record each animal, twice a week, on the first two light hours. From the videos, frequency of behaviors was registered as anxiety-like, grooming, alert, hanging position, staying in nest box and feeding using continuous focal animal sampling method. Simultaneously, the calls emitted in the experimental room were recorded by a single microphone centrally located and categorized as affiliative (whirr, chirp), contact (phee), long distance (loud shrill), agonistic (twitter) and alarm (tsik, seep, see). EA was assessed on the third hour after lights onset on the last week of each condition. In a first session, marmosets were exposed to one unfamiliar object during 15 min and 24h later, on the second session, a novel object was added to evaluate RM. Results showed that long days caused a decreased of amplitude and period variance of the CRA, but not short days. Short days decreased the total daily activity and active phase duration. On long days, active phase duration increased due to an advance of activity onset in relation to symmetric days. However, not all subjects started the activity earlier on long days. The activity offset was similar to symmetric days for the majority of marmosets. Results of EA showed that RM was not affected by short or long days, and that the marmosets exhibited a decreased in duration of EA on long days. Frequency and type of calls and frequency of anxiety-like behaviors, staying in nest box and grooming were lower on the first two light hours on long days. Considering the whole active phase of marmosets as we elucidate the results of vocalizations and behaviors, it is possible that these changes in the first two light hours are due to the shifting of temporal distribution of marmoset activities, since some animals did not advance the activity onset on long days. Consequently, the marmosets mean decreased because the sampling was not possible. In conclusion, marmosets synchronized the CRA to the tested photoperiods and as the phase angle varied a lot among marmosets it is suggested that they can use different strategies. Also, long days had an effect on activity-rest cycle and exploratory behaviors

Structural phase transitions of PbZr0.52Ti0.48O3 ceramic: An infrared spectroscopy study

The recent discovery of a ferroelectric monoclinic phase in the PbZr1-xTixO3 (PZT) system attained the attention of several researchers due to the possibility of understanding the relationships between structural features and piezoelectric properties. The nature of the monoclinic phase in some PZT compositions remains controversial and unclear. In this work, structural phase transitions of PbZr0.52Ti0.48O3 ceramic were investigated by infrared spectroscopy as a function of temperature. Studies were centered on nu(1)-stretching modes and corresponding half width Wi as a function of temperature. The occurrence of the anomalies in the infrared spectra as a function of temperature suggests the following monoclinic ( LT) -> monoclinic ( HT) -> tetragonal phase transition were observed at 183 K and at 263 K.

Analysis of natural cis- and trans-polyisoprene mixtures by near-infrared spectrophotometry

Natural trans- and cis-polyisoprenes and mixtures of these polymers were analysed by near-infrared spectrophotometry. The relative absorptivity data versus the amount of isomers in synthetic mixtures showed a non-linear behaviour. The results are compared with literature data from polyisoprenes extracted from other vegetal species. (C) 2000 Elsevier B.V. Ltd. All rights reserved.

Monoclinic-tetragonal phase transition in Pb(Zr1-xTix)O-3 studied by infrared spectroscopy

The discovery of a new monoclinic phase in the PbZr1-xTixO3 (PZT) system in the vicinity of the morphotropic phase boundary (MPB), previously considered as a region where the rhombohedral and tetragonal phases of PZT coexist, was recently reported. Investigations of this new phase were reported using different techniques such as high-resolution synchrotron x-ray powder diffraction and Raman spectroscopy. The main objective has been to define a new phase diagram of PZT. In this context, infrared spectroscopic studies were performed in the vicinity of the MPB and studies were initially centred on a PZT sample with x = 0.49 mol% Ti content. Results suggested that the monoclinic --> tetragonal phase transition occurs at 237 K, confirming the use of IR as a useful technique to investigate this phase transition.

Infrared studies of the monoclinic-tetragonal phase transition in Pb(Zr, Ti)O-3 ceramics

Recently, the observation of a new monoclinic phase in the PbZr1-xTixO3 (PZT) system in the vicinity of the morphotropic phase boundary was reported. Investigations of this new phase were reported using different techniques such as high-resolution synchrotron x-ray powder diffraction and Raman spectroscopy. In this work, the monoclinic --> tetragonal phase transition in PbZr0.50Ti0.50O3 ceramics was studied using infrared spectroscopy between 1000 and 400 cm(-1). The four possible nu(1)-stretching modes (Ti-O and Zr-O stretch) in the BO6 octahedron in the ABO(3) structure of PZT in this region were monitored as a function of temperature. The lower-frequency mode nu(1)-(Zr-O) remains practically unaltered, while both intermediate nu(1)-(Ti-O) modes decrease linearly as temperature increases from 89 to 263 K. In contrast, the higher-frequency nu(1)-(Ti-O) and nu(1)-(Zr-O) modes present anomalous behaviour around 178 K. The singularity observed at this mode was associated with the monoclinic --> tetragonal phase transition in PbZr0.50Ti0.50O3 ceramics.

New far-infrared laser lines from CH3OD methanol deuterated isotope

We report on a study of the CH3OD molecule in a search for new far-infrared (FIR) laser lines. For optical pumping of large offset vibrational absorption transitions, a continuous-wave waveguide CO2 laser with 300 MHz tunability around each line was used for the first time. As a consequence, 17. new far-infrared laser emissions were observed. For these lines, we also present data on wavelength, intensity, offset, relative polarization, and optimum operation pressure.

The vinyl bromide optically pumped far infrared laser: New large offset emissions

We present the results of a study on vinyl bromide for the search for new far infrared (FIR) laser lines. As the pump source, we use a CW waveguide CO2 laser with a tunability of 290 MHz around each line in order to pump large offset vibrational transitions. As a consequence, we obtained 28 new FIR laser emissions; 24 of them have wavelengths greater than 500 mum and are, therefore, suitable to be used in high-field EPR spectroscopy, For each of the new lines, we give the wavelength, the offset of the pumping transition with respect to the center Frequency of the CO2 emission, the polarization relative to that of the pumping laser line, the operating pressure, and the relative intensity. We also present a catalog including data of all of the FIR laser lines observed from this molecule up to now.

Structural Phase Transition Studies on PMN-0.35PT using Infrared Spectroscopy

The purpose of the present work is to report studies on structural phase transition for PMN-xPT ferroelectric, with melt PbTiO3 composition around the MPB (x = 0.35 mol %), using infrared spectroscopy technique. The study was centered on monitoring the behavior of the 1-(NbO), 1-(TiO) and 1-(MgO) stretching modes as a function of temperature. The increasing as a function of temperature for 1-(TiO) and 1-(MgO) modes, observed between 230 and 300 K, can be related to the monoclinic (MC) + tetragonal (T) phase coexistence in the PMN-PT.

Infrared spectroscopy: a tool for determination of the degree of conversion in dental composites

Infrared spectroscopy is one of the most widely used techniques for measurement of conversion degree in dental composites. However, to obtain good quality spectra and quantitative analysis from spectral data, appropriate expertise and knowledge of the technique are mandatory. This paper presents important details to use infrared spectroscopy for determination of the conversion degree.