Thesis (MTech (Electrical Engineering))--Peninsula Technikon, 2002 / This research outlines the development and design of an infrared radiation heating profile controller. The study includes both the theoretical aspects of the design process as well as giving an overview of the practical facets involved. The controller was subjected to comparative testing with a proportional control model, in order to observe its performance and validate its effectiveness. A need exists for these types of controllers and proved to be the motivation to embark on this investigation. Controllers of this nature that are commercially available either lacks the functionality of this unit or are too expensive to implement for research purposes. This unit was designed with cost effectiveness in mind but still meet the standards required of an industrial style controller. To this end the construction was completed using low cost and affordable electronic components. Heating profiles are necessary and useful tools for the proper processing of a host of materials. The controller developed in this research is able to within a fair degree of accuracy track a heating profile. The results confirm that this programmable control model to be a benefit and a valuable tool in temperature regulation. This means that intensive studies into the effects of infrared radiation on materials are now feasible. Research of this nature could possibly expand the application of infrared as a heating mechanism. Although tests were conducted on this controller, they are not meant to serve as an exhaustive analysis. The conclusions of these examinations do reveal the benefit of such a controller. More rigorous investigation is suggested as a subject for further study.

Made available in DSpace on 2014-10-09T12:26:16Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:10:14Z (GMT). No. of bitstreams: 1 13710.pdf: 4475928 bytes, checksum: 085de71450d1d624d06f238b8ba1835c (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:26:16Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:10:32Z (GMT). No. of bitstreams: 1 13707.pdf: 1360257 bytes, checksum: c3e632331f4dc215d42873a09ef248bb (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo, Sao Paulo

Orientador: Kil Jin Park / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-13T20:46:30Z (GMT). No. of bitstreams: 1 Oliveira_RafaelAugustusde_D.pdf: 10632157 bytes, checksum: 6f94ba79ddf0845152f3eee7a34b2df2 (MD5) Previous issue date: 2009 / Resumo: No processo de secagem, a utilização de equipamentos que promovem um incremento nos coeficientes de transferência é de grande interesse. A secagem vibro-fluidizada se baseia na passagem de um fluxo de ar aquecido através do leito do material colocado sobre uma grade distribuidora de ar, aliado ao efeito mecânico da agitação do leito do secador. É utilizada para materiais termolábeis, que requerem tempos de residência curtos, altas taxas de secagem e baixas temperaturas de secagem, tais como: materiais granulares, pastas e pós; tanto para materiais farmacêuticos, biológicos e alimentares. Neste estudo pretendeu-se então, submeter materiais biológicos a um processo de secagem utilizando diversos dispositivos e avaliar o comportamento da secagem, consumo de energia, propriedades do material e extração de componente. Os secadores utilizados foram: secador vibrofluidizado (patente PI 9302443-6 e auxílio FAPESP n°: 00/05543-2) e secador agitador/misturador (patente PI 0506639-5). O processo de secagem foi avaliado com grãos de milho no secador vibrofluidizado e batata e raízes de yacon no secador agitador/misturador. Realizaram-se o levantamento do tempo de residência com análise de imagens e seleção manual; levantamento da perda de carga e do perfil de velocidade no secador vibrofluidizado com sistemas aberto e fechado. A partir dos testes para levantamento da distribuição do tempo de residência, foi desenvolvida uma metodologia para avaliação da quantidade de traçador na massa de produtos com base somente em imagens digitais das amostras. Com isso é possível encontrar valores de tempo de residência sem o uso de práticas manuais e, consequentemente, trabalhosas. Levantamento do tempo de residência foi também realizado no secador agitador/misturador que pode ser utilizado tanto como secador contínuo como secador a batelada. Esse secador permite a aplicação de vácuo e de energia radiante infravermelha durante a secagem. Foi utilizado, ainda, na secagem de batata e raiz de yacon e na avaliação destes recursos tecnológicos. A extração de inulina proveniente das raízes de yacon foi avaliada. A utilização de temperaturas de secagem mais altas resultou em um maior consumo de energia por quilograma de água retirada do produto, enquanto que a aplicação de energia infravermelha durante a secagem reduziu o tempo de secagem e, consequentemente, a energia elétrica gasta. A influência dos parâmetros operacionais de secagem não se mostrou significativa estatisticamente na extração de inulina a partir de raízes secas de yacon / Abstract: In the drying process, the use of equipments which promote an increment in the transfer coefficients is of great interest. The vibrofluidized drying is based on the passage of a warm air flow through the bed of the material put on an air distributing grille, allied to the mechanical effect of the agitation of the drying bed. It is used for thermo sensible materials, which request short residence times, high drying taxes and low drying temperatures, such as: granular materials, pastes and powders; so much for pharmaceutical, biological and food materials. In this project it was intended then, to submit biological materials to a drying process using several devices and to evaluate the behavior of the drying, energy consumption, material properties and component extraction. The used dryers were: vibrofluidized dryer (patent PI 9302443-6 and FAPESP financial support n°: 00/05543-2) and agitator/mixer dryer (patent PI 0506639-5). The drying process was evaluated with corn grains in the vibrofluidized dryer and potato and yacon roots in the agitator/mixer dryer. The survey of the residence time with analysis of images and manual selection; the survey of pressure drop and air velocity profile in the vibrofluidized dryer in open and closed systems were also carried out. Starting from the survey of the residence time distribution, a methodology was developed for evaluation of the tracer amount in the mass of products based on only digital images of samples. In this way, it is possible to find residence time without using manual procedures and, consequently, laborious. Survey of the residence time was accomplished also in the agitator/mixer dryer which can be used as continuous dryer as well as batch dryer. This dryer allows vacuum and infrared radiant energy application during drying. It was used, even, in potato and yacon root drying and in the evaluation of these technological devices. The extraction of inulin originated from yacon roots was also evaluated. The use of higher drying temperatures resulted in a larger consumption of energy per kilogram of removed water from product, while the infrared energy application during drying reduced the drying time and, consequently, the consumed electric energy. The influence of drying operational parameters was not statistically significant in the extraction of inulin from dried yacon roots / Doutorado / Tecnologia Pós-Colheita / Doutor em Engenharia Agrícola

Goal of this thesis is to study infrared detection by means of thermal. Theoretical part of this work gives an introduction to thermal detectors.

No description available.

Generation and detection of circularly-polarized (CP) radiation in the 8- to 12-μm band of the infrared (IR) spectrum is crucial for polarization sensing and imaging scenarios. There is very little naturally occurring CP radiation in the long-wave IR band, so that useful functionalities may be obtained by exploiting preferential radiation and transmission characteristics of engineered metamaterials. Conventional CP devices in the IR utilize birefringent crystals, which are typically bulky and expensive to manufacture. The operation of these devices is generally optimized at a single wavelength. Imaging in the long-wave IR is most often broadband, so that achromatic CP-device behavior is highly desirable from a fluxtransfer viewpoint. Also, size, weight and cost are significant drivers in the design of practical IR systems. Thus a solution is sought with a convenient thin planar form factor. This dissertation will demonstrate a novel planar periodic subwavelength-microstructured approach derived from classical radiofrequency meanderline designs that are able to generate CP radiation over a broad IR band while maintaining a low fabrication profile. We investigate issues regarding efficiency as a function of the number of layers in the device structure; reflective, transmissive, and emissive behavior; strategies for broadband achromatization; and thermal-isolation requirements between the active blackbody reservoir and the top of the planar device, to achieve a given degree of polarization. Theoretical, numerical, and experimental findings are presented that confirm the feasibility of this class of devices for use in a wide variety of situations, from polarization imaging and spectroscopy to industrial laser processing and machining.

Master of Science / Department of Grain Science and Industry / Bhadriraju Subramanyam / Organic, hard red winter wheat of 11% moisture was tempered with distilled water to moisture levels of 16 and 18% and held for 8, 16, and 24 h. At each moisture and holding time wheat was unexposed (control) or exposed to infrared radiation for 1, 1.5, and 2 min using a bench-top flameless catalytic infrared emitter. The mean external grain temperatures for 16% mc wheat measured with thermocouples during infrared exposure of 1, 1.5, and 2 min ranged from 77.4-83.1, 93.7-101.2, and 91.2-98.3°C, respectively; corresponding mean internal temperatures were 67.3-76.4, 80.0-85.6, and 81.3-93.2°C. Minor differences in kernel moisture, hardness, and weight were observed among treatments. Tempered wheat after infrared exposure among treatments lost 1.5-2% moisture. Infrared exposure of wheat reduced initial bacterial loads (6.7×10[superscript]4 CFU/g) by 98.7% and fungal loads (4.3×10[superscript]3 CFU/g) by 97.8% when compared with those on untreated wheat. Wheat tempered to 18% and exposed for 2 min to infrared radiation lost 2% moisture, and this wheat when milled had a yield of 73.5%. The color of flour from infrared- exposed wheat was slightly dark (color change, ΔE = 0.31) when compared with untreated flour. Differential scanning calorimetry showed that flours from infrared exposed wheat had lower enthalpy (3.0 J/g) than those unexposed to infrared (3.3 J/g). These flours were adversely affected because they had longer mixing times (7-15 min) at all infrared exposures due to the presence of insoluble polymeric proteins (up to 60%). Microbial loads in flour from wheat tempered to 18% and exposed for 1-2 min had 0.6-2.4 log reduction compared to flour from untreated wheat. Wheat tempered to 18% moisture with electrolyzed-oxidizing (EO) water reduced bacterial and fungal loads up to 66%. EO water tempered wheat exposed for 1, 1.5, and 2 min to infrared radiation showed microbial reductions of 99.5% when compared with control wheat. Infrared treatment of tempered wheat cannot be recommended as it adversely affected flour functionality. The use of EO water for tempering as opposed to potable water that is generally used in mills slightly enhances microbial safety of hard red winter wheat.

A 'model-to-radiance' comparison of simulated brightness temperatures and radiances from the Hadley Centre Global Environmental Model 2 (HadGEM2-A) with longwave measurements from the High Resolution Infrared Radiation Sounder/4 (HIRS/4) and the Infrared Atmospheric Sounding Interfermeter (IASI) onboard the MetOp-A satellite is presented for all-sky and clear-sky global means. The fast Radiative Transfer model for TOVS 10 (RTTOV-10) is applied to HadGEM2 output to simulate observational-equivalent data. The results are compared with corresponding broadband analyses. A method is developed to extend hyperspectral IASI radiances to cover the whole outgoing terrestrial spectrum, in order to identify any compensating biases, and explore wavebands in the unobserved Far Infrared (FIR) region. For the all-sky HIRS analysis, the model overestimates brightness temperatures in the atmospheric window region with the greatest biases over areas associated with deep convective cloud. In contrast to many global climate models, much smaller clear-sky biases are found indicating that model clouds are the dominating source of error. Simulated values in upper atmospheric CO2 channels approximate observations better as a result of compensating cold biases at the poles and warm biases at lower latitudes, due to a poor representation of the Brewer Dobson circulation in the 38 level 'low-top' configuration of the model. Simulated all and clear-sky outgoing longwave radiation evaluated against the Clouds and the Earth's Radiant Energy System (CERES) and HIRS OLR products reveal good agreement, in part due to cancellation of positive and negative biases. Through physical arguments relating to the spectral energy balance within a cloud, it is suggested that broadband agreement could be the result of a balance between positive window biases and unseen negative biases originating from the water vapour rotational band in the FIR (not sampled by HIRS). Simple sensitivity tests show that dramatically altering existing cloud properties has little effect on the prominent window biases, however raising clouds a maximum of 5 atmospheric levels minimises the error in cloud contaminated channels, due to the introduction of spatially compensating errors. Sensitivities to the way ice clouds are parameterised in RTTOV-10 display a range of up to 2.5 K in window channels but absolute biases still exceed 3 K for all choices. Because of the lack of satellite based FIR observations due to a technological gap in the spectral region, an algorithm is created to 'fill in' the available data. Correlations between selected IASI channels and simulated unobserved wavelengths in the far infrared are used to estimate radiances between 25.25 - 644.75 cm-1 at 0.5 cm-1 intervals. The same method is used in the 2760 - 3000 cm-1 region. The spectrum is validated by comparing the Integrated Nadir Longwave Radiance (INLR) product (spanning the whole 25.25 - 3000 cm-1 range) with the corresponding broadband measurements from the Clouds and the Earth's Radiant Energy System (CERES) instrument on the Terra and Aqua satellites at simultaneous nadir overpasses, revealing mean differences of 0.3 Wm-2sr-1 (0.5% relative difference) lower for IASI relative to CERES and significantly lower biases in nighttime only scenes. Averaged global data over a single month produces mean differences of about 1 Wm-2sr-1 in both the all and the clear-sky (1.2% relative difference). The new high resolution spectrum is presented for global mean clear and total skies where the far infrared is shown to contribute 44% and 47% to the total OLR respectively, which is consistent with previous estimates. In terms of spectral cloud radiative forcing, the FIR contributes 19% and in some subtropical instances appears to be negative, results that would go un-observed with a traditional broadband analysis. The equivalent complete IASI OLR model product is simulated from GCM data using RTTOV-10. The same process of applying predictors to the satellite measurements is applied to the model simulated radiances, with appropriate modifications, to produce a directly comparable model product. Annual mean all-sky radiances are still greatly overestimated at all wavenumbers with a total radiance bias of 4.52 Wm-2 across the whole range. Compensating negative biases outside of the HIRS coverage that were hypothesised are absent, with the far infrared contributing to the overall bias rather than cancelling it. Equivalent clear-sky biases are much lower overall at 0.39 Wm-2, in part due to spectral and spatial cancellation of errors. A flux-to-flux comparison is enabled by estimating the spatial distribution of anisotropic factors, using collated HIRS OLR fluxes and IASI OLR radiances, which yields global mean model fluxes in excess of 12 Wm-2 higher than observations in the all-sky. The difference between this and the fluxes calculated using the climate model's broadband radiation code (Edward-Slingo) are around 10 Wm-2 which is outside the range of uncertainty in the method used to estimate the flux. However, it is discussed that tuning of the climate model's broadband code to known flux values is a required practice to ensure global energy budgets balance but can produce inaccurate parameterised variables. An equivalent analysis adjusting the ice cloud parametrisation to reflect the radiances that have the biggest differences to the original configuration selected showed a bias reduction of 4.5 Wm-2, which is still not enough to completely explain its size, suggesting the existence of residual cloud problems. Finally, it is suggested that the way forward in separating and constraining cloud errors, in both radiative transfer codes, is a rigorous process of testing them with observation cloud properties and reanalysis data as inputs.

Thesis (MSc)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: The efficient manipulation of various nonlinear optical processes frequently requires the shaping of the laser beams used for these processes. Three beam shaping techniques were investigated in this thesis. The focussing of Gaussian laser beams was investigated analytically, in order to efficiently manipulate the focussed beam characteristics. The beam-shaping characteristics of a diffractive optical element (DOE) was investigated numerically, which illustrates the beamshaping capability of the DOE, and identifies the critical parameters in experimental situations. The use of a waveguide as beam shaping device was investigated analytically and experimentally, and characterized for use with the available tunable laser sources. A Raman laser, or Raman shifter, employs stimulated vibrational Raman scattering to generate laser radiation at shifted frequencies. The waveguide was successfully applied as a beam shaping device in the Raman laser system, for optimisation of the process. The Raman laser system was investigated experimentally and characterized for use with the available tunable laser sources. The successful generation of laser radiation at shifted frequencies illustrates the usefulness of the system for generating tunable red-shifted frequencies. The results of this work allow the simple and efficient application of the Raman laser to generate laser radiation at shifted frequencies, in particular tunable infrared laser radiation which is desirable for molecular spectroscopy. / AFRIKAANSE OPSOMMING: Nie-liniêre optiese prosesse kan meer effektief benut word deur die vervorming van die laserbundels wat gebruik word in die prosesse. In hierdie tesis word drie laserbundel-vervormings tegnieke ondersoek. Die fokussering van Gaussiese laserbundels word analities ondersoek, om die gefokusseerde bundel se eienskappe effektief te manipuleer. Die bundel-vervormings eienskappe van ’n diffraktiewe optiese element word numeries ondersoek, wat die effektiwiteit van die bundelvervorming en die sensitiewe parameters in die sisteem uitwys. Die gebruik van ’n golfgeleier as ’n bundel-vervormings tegniek word ook analities en eksperimenteel ondersoek, en gekarakteriseer vir gebruik met die gegewe golflengte-verstelbare laser sisteme. ’n Raman laser, wat gestimuleerde vibrasionele Raman verstrooiing gebruik om laser lig te genereer by Stokes-verskuifde frekwensies, word ondersoek. Die golfgeleier word effektief gebruik as ’n bundel-vervormings tegniek in die Raman laser, om die bogenoemde nie-liniêre proses te optimeer. Die Raman laser was eksperimenteel ondersoek en gekarakteriseer vir gebruik met die gegewe golflengte-verstelbare lasers. Laser lig by verskuifde golflengtes is suksesvol gegenereer, wat die bruikbaarheid van die sisteem illustreer. Van belang is spesifiek verstelbare infrarooi laser lig, wat gebruik kan word in die laser-spektroskopie van molekules. Die resultate van hierdie werk lei tot die eenvoudige en effektiewe gebruik van die Raman laser, om langer golflengtes in die infrarooi gebied te genereer met ’n gegewe laser in die sigbare gebied.