Incandescent Source Research Articles

UJI KINERJA OVEN PENGERING SPESIMEN CAT TIPE TERTUTUP DENGAN PENAMBAHAN ISOLATOR ALUMINIUM FOIL

UJI KINERJA OVEN PENGERING SPESIMEN CAT TIPE TERTUTUP DENGAN PENAMBAHAN ISOLATOR ALUMINIUM FOIL

Characterization of the electrical properties of an optical device manufactured with CMOS 0.35 μm technology

<p>Currently, the relevance of optical devices has increased due to the physical limitations of the electrical transmission medium and the proximity of the limit of Moore's Law. Furthermore, the fabrication of optical devices on monolithic silicon substrates has gained importance in recent years thanks to manufacturing technologies in the microelectronics industry. For this reason, this paper aims to carry out the electrical characterization of an optical device manufactured with commercial austria micro syste m technology of complementary metal oxide semiconductors of 0.35 μm. The methodology consists of implementing an optical device, with an incandescent optical source called a microlamp, a waveguide and a photodiode. The microlamp was projected between two m etal layers connected by tungsten vias that act as filaments covered by SiO 2 dielectric to prevent oxidation. The results of the electrical characterization of the optical device show that the microlamp reaches a maximum current of 48 mA and stops working at higher currents. The waveguide was designed with a SiO 2 core and it was discovered that the TiN layers were found to be part of the waveguide causing it to behave as an emitter in the 2.5 - 5 <em>µ</em>m region.</p>

Исследование влияния соотношения реакционных газов при осаждении покрытия системы Ti–Al–C–N на изностойкость режущего инструмента

The paper presents the results of the study of the component composition of the reaction gases mixture when synthesizing carbonitride coatings of the Ti–Al–C–N system influencing the cutting tool durability. The coating was applied using the updated unit NNV-6.6-I1 by spraying from two one-component cathodes assisted by the incandescent cathode plasma source. During applying the coating, the mixture of reaction gases of N2 nitrogen and C2H2 acetylene in the ratio of 1:4, 2:3, 3:2, and 4:1 was delivered to the chamber. The paper presents the results of measuring the microhardness of studied specimens, which show that a sample with the coating deposited at the reaction gases ratio of N2:C2H2=2:3 had the largest microhardness value (4870 HV0.05). The paper presents the results of field tests of carbide-tipped tools with the studied coatings. Durability tests identified that a cutter with the coating deposited at the gas ratio of N2:C2H2=4:1 increases the tool durability ten times compared to a cutting tool without coating. Using the electron microscopy method, the authors investigated the chemical composition of the tool cutting face after tests. The analysis of the chemical composition of the surface after cutting showed that the content of coating elements on the surface of the sample with a coating deposited at the 4:1 ratio of the reaction gases of nitrogen and acetylene was considerably higher than that of other studied coatings, which indicates the less coating wear. However, ferrum is present in some areas of the cutting face, which says about the adhesion of treated material to the tool.

Computational simulation of heat conduction on different surfaces

The heat conduction from the initiation source to the adjacent surfaces, is a physical phenomenon worth considering in the process of analysing the fire. This complex phenomenon describes how the transport, the exchange, and the redistribution of the thermal energy are carried out. It is based on the theoretical knowledge that describes the initiation and fire evolution in time. The flames transfer heat from nearby surfaces through two distinct physical processes, namely convection and radiation. Another way of heat transfer is conduction, in which case the transfer of heat implies the existence of an environment that can be of a gaseous, liquid or solid nature. This paper illustrates a brief presentation of how the heat transfer is carried out, the influence of the three phenomena on the mechanism of initiation and development of the fire, and can be seen as well as a case study aimed at the computerized simulation of a fire, having as a source of initiation the radiative transfer of heat to the surrounding combustible surfaces. The ignition of the different materials in a room, due to radiation exposure emitted by an incandescent source at a certain distance from them, even without having a direct contact to the flames, is a common reality in the case of fires that occur in both residential and industrial environments. This fact justifies the importance of thermal radiation study.

Rapid protocol to evaluate the photoprotective effect of film-forming formulations on mangoes

Abstract Sunburn is responsible for significant losses in post-harvest and has motivated studies to diminish its effect on different types of cultivars. Thus, the present study proposes a rapid protocol to evaluate the photoprotective effect of suppressive formulations. The experiment consisted in placing fruits (mango) covered with different suppressor formulations about 7 centimeters from an incandescent source and measuring the surface temperature variation employing a thermometer and thermal camera. The formulations were based on a filmogenic polysaccharide (galactomannan) and reflective additives (hydroxyapatite, montmorillonite and bentonite clays). The best result was achieved with a coating with bentonite as an additive, which showed a statistical difference in temperature (43.3±2.1 °C) compared with the control (52.1±3.0 °C) and the standard kaolinite coating (39.4±1.7 °C). Thus, it was proven the viability of the protocol as well as of the alternative formulations in to reduce the sunburn effect. This contributes to solution for the establishment of the Tropical Agriculture.

Large-area epitaxial growth of MoSe2 via an incandescent molybdenum source

We have developed an incandescent Mo source to fabricate large-area single-crystalline MoSe2 thin films. The as-grown MoSe2 thin films were characterized using transmission electron microscopy, energy dispersive x-ray spectroscopy, atomic force microscopy, Raman spectroscopy, photoluminescence (PL), reflection high energy electron diffraction (RHEED) and angular resolved photoemission spectroscopy (ARPES). A new Raman characteristic peak at 1591 cm−1 was identified. Results from Raman spectroscopy, PL, RHEED and ARPES studies consistently reveal that large-area single crystalline mono-layer of MoSe2 could be achieved by this technique. This technique enjoys several advantages over conventional approaches and could be extended to the growth of other two-dimensional layered materials containing a low-vapor-pressure element.

The influence of optical properties of paints and coatings on the efficiency of infrared nondestructive testing applied to aluminum aircraft structures

IR NDT (Infrared Nondestructive Testing) is a popular method for detecting defects in composite, ceramic, and metallic structures. The effectiveness of IR NDT depends on various thermal and optical properties of the material being tested. The thermal properties, including thermal conductivity, thermal diffusivity, specific heat and density are important and have been discussed extensively in many treatises on IR NDT. However the optical properties of the surface are equally important and while the thermal properties cannot be changed, sometimes the optical properties can be.Bare metal surfaces have high reflectivities and low emissivities, and as a result, they are generally not good candidates for IR NDT. Painted, coated, anodized, and oxidized metal surfaces can, in some cases, be successfully tested with IR NDT, but the effectiveness depends on the optical properties of the surface. It is well known by IR NDT practitioners that the easy solution to the testing of reflective materials is to paint the surface black. However, this is not always practical and it may not be permitted by the “owner” of the part.This paper demonstrates a process of analyzing the interaction of spectral curves that are relevant to the IR NDT process. This process can be used to evaluate the effectiveness of an IR NDT process for use on real parts with specific coatings and can help select a coating that may improve the effectiveness. This paper shows examples of optical properties for some typical paints and coatings that may be used on aluminum aircraft structures. It shows the spectrum of a generic incandescent radiant heat source and how the energy from this source is absorbed by several of these paints. Further, it shows the interaction between an IR camera detector response curve and the other curves. And finally, it shows how these three can be combined to produce an “IR NDT” efficiency rating for several examples.

Tailoring high-temperature radiation and the resurrection of the incandescent source.

In solar cells, the mismatch between the Sun's emission spectrum and the cells' absorption profile limits the efficiency of such devices, while in incandescent light bulbs, most of the energy is lost as heat. One way to avoid the waste of a large fraction of the radiation emitted from hot objects is to tailor the thermal emission spectrum according to the desired application. This strategy has been successfully applied to photonic-crystal emitters at moderate temperatures, but is exceedingly difficult for hot emitters (>1,000 K). Here, we show that a plain incandescent tungsten filament (3,000 K) surrounded by a cold-side nanophotonic interference system optimized to reflect infrared light and transmit visible light for a wide range of angles could become a light source that reaches luminous efficiencies (∼40%) surpassing existing lighting technologies, and nearing a limit for lighting applications. We experimentally demonstrate a proof-of-principle incandescent emitter with efficiency approaching that of commercial fluorescent or light-emitting diode bulbs, but with exceptional reproduction of colours and scalable power. The ability to tailor the emission spectrum of high-temperature sources may find applications in thermophotovoltaic energy conversion and lighting.

Colour of Stone Slabs under Different Standard Illuminations

Spectral measurements have been carried out on polished stone slabs to show the accuracy of theoretical colorimetric calculations on perceptual differences of color appearance under various standard illuminations. Effects of the different spectral characteristics of the light source on colorization of the samples have been also studied to analyze the changes of color sensation on the samples in connection with the changes on the type of the illuminating source. Solar light (Standard Illuminant D65), basic incandescent source (Standard Illuminant A) and a basic fluorescent source (Standard Illuminant F11) have been tested on Tardos red limestone, Siklos green limestone, Carrara white and gray marbles and diorite samples. Colorizing effects of the examined illuminations are compared to Standard Illuminant E – the theoretically perfect white source.

Can the Efficacy of the Incandescent Source be Improved in How Far? : Microcavity Lamp and Cluster Source(<Special Issue>130Years of History and the Future of the Incandescent Lamp)

Can the Efficacy of the Incandescent Source be Improved in How Far? : Microcavity Lamp and Cluster Source(<Special Issue>130Years of History and the Future of the Incandescent Lamp)

Analysis of spectroscopic diffuse reflectance plots for different skin conditions

Optical means of characterizing tissues have gained importance due to its noninvasive nature. Spectral characteris- tics of the components provide useful information to identify the components, because different chromophores have different spectroscopic responses to electromagnetic waves of a certain energy band. The purpose of this study is to determine whether visible/near-infrared diffuse reflectance spectroscopy can be used to non-invasively characterize skin diseases in vivo. An optical fiber spectrometer is set up for obtaining diffuse reflectance spectra. The method involves exposure of skin surface to white light produced by an incandescent source. The back scattered photons emerging from various layers of tissue are detected by spectrometer resulting in diffuse reflectance spectra. For the present study different skin conditions like - warts, vitiligo, thrombus (due to injury) and angioma are chosen. The spectral data obtained from the scan are plotted and compared. More or less, the shapes of the spectral curves for various skin conditions resemble. In order to characterize and differentiate different diseased state spectral analysis based on Ratio analysis, Student's t-tests and difference plot are carried out. Based on the analysis the relative spectral intensity changes are quantified and the spectral shape changes are enhanced and more easily visualized on the spectral curves, thus assisting in differentiating the normal tissue from the one affected by disease.

Analysis of spectroscopic diffuse reflectance plots for different skin conditions

Optical means of characterizing tissues have gained importance due to its noninvasive nature. Spectral characteristics of the components provide useful information to identify the components, because different chromophores have different spectroscopic responses to electromagnetic waves of a certain energy band. The purpose of this study is to determine whether visible/near-infrared diffuse reflectance spectroscopy can be used to non-invasively characterize skin diseasesin vivo.An optical fiber spectrometer is set up for obtaining diffuse reflectance spectra. The method involves exposure of skin surface to white light produced by an incandescent source. The back scattered photons emerging from various layers of tissue are detected by spectrometer resulting in diffuse reflectance spectra.For the present study different skin conditions like – warts, vitiligo, thrombus (due to injury) and angioma are chosen. The spectral data obtained from the scan are plotted and compared. More or less, the shapes of the spectral curves for various skin conditions resemble. In order to characterize and differentiate different diseased state spectral analysis based on Ratio analysis, Student'st-tests and difference plot are carried out.Based on the analysis the relative spectral intensity changes are quantified and the spectral shape changes are enhanced and more easily visualized on the spectral curves, thus assisting in differentiating the normal tissue from the one affected by disease.

Fourier Transform Spectrometry with a Near-Infrared Supercontinuum Source

Optical fiber based supercontinuum light sources combine the brightness of lasers with the broad bandwidth of incandescent lamps and thus are promising candidates for sources in spectroscopic applications requiring high brightness and broad bandwidth. Herein, near-infrared (IR) Fourier transform (FT) spectrometry with a supercontinuum (SC) light source is investigated. The efficient, collimated propagation of broad bandwidth SC light through an 18 m path length multipass cell is demonstrated. A normalized spectral difference is calculated for the SC spectrum on consecutive FT mirror scans and is found to vary by less than 0.5%, indicating excellent spectral stability. The rms noise on zero absorbance lines is obtained as a function of the number of mirror scans at 0.125, 2, and 16 cm(-1) resolution for both the SC and conventional tungsten lamp source. The SC source has approximately a factor of ten times more noise than the lamp under comparable conditions for each resolution and data acquisition time. This clearly indicates that spectral acquisition with the SC source is not detector noise limited. NIR-FT spectra of methane and methyl salicylate, acquired with both the SC and lamp source, are reported. These spectra illustrate the advantage the SC source has over the incandescent source in that it can efficiently traverse long path lengths, thus providing a sensitivity advantage. The spectra also demonstrate the disadvantage of the SC source with respect to the lamp in the increased level of amplitude noise. Prospects for the future use of SC sources in absorption spectroscopy, including possible noise mitigation strategies, are briefly discussed.

White Light Photorefractive Phase Zone Plates

Incoherent white light from an incandescent source is employed to fabricate volume phase zone plates in LiNbO3: Fe, for the first time to our knowledge, which can guide and modulate the input white light or laser light. The diffractive efficiency of the white light volume phase zone plates fabricated can reach as high as 12%. In addition, we test the volume phase zone plates by a probe beam and find that the volume phase zone plate is present in the direction perpendicular to the c-axis and absent in the direction parallel to the c-axis. This directly proves the existence of photovoltaic photorefractive anisotropy of white light.

Processing of Collagen Gels to Create in Vitro Cell Growth Matrix Without Damage to the Collagen Native Structure

This preliminary work explores a technique for processing collagen gels to provide a structured matrix support for cell growth and other tissue engineering applications without using cyto-toxic photo-initiators. Collagen gels can be structured by techniques similar to those of rapid manufacturing and retain the fibril structure of native collagen. Incorporation of alpha-modified minimal essential medium (MEM) in the collagen solution improved the rate of gelation in a cell-friendly way. Local gelation of a collagen solution formulated with alpha-modified MEM can be achieved by exposure to radiation from a remote incandescent lamp source indicating that it may be possible to prepare structured gels by lithographically based rapid manufacturing processes. Exposure of the alpha-modified MEM collagen solution to the radiation also increased the thickness of the collagen fibrils formed during the gelation process to create a more structured gel. Methyl blue staining, scanning electron microscope (SEM), and differential scanning calorimetry (DSC) experiments confirmed the collagen was not denatured, i.e. the native structure of collagen was retained.

Time Resolved Photoconduction Studies of Uniformly Doped and p-n Junction Si Nanowires

ABSTRACTThe time resolved and DC photoconduction characteristics of Si nanowire devices are described. Si nanowires with diameters ranging from 20-100 nm were grown using the vapor-liquid-solid (VLS) growth mechanism under standard conditions and devices were fabricated in a back-gate field effect transistor (FET) configuration using simple photolithography. It is shown that under certain biasing conditions, illumination with light from light emitting diodes with wavelengths ranging from 480 nm to 625 nm causes changes in current as high as 4%. On the other hand, illumination by a broadband incandescent source causes a ∼4.1% percent change in current. Photoconductive decay curves show bi- and tri-exponential behavior, indicative of multiple potential recombination mechanisms occurring within the Si nanowire devices. p-n doped Si nanowires show similar behavior. Studies under various drain and gate voltages provides insight into the proposed mechanism. It is argued that the Shottky barrier plays a strong role in the observed photoconduction process in these wires, as do transitions involving surface and deep level trap states.

White-light photorefractive phase mask

A volume photorefractive phase mask has been fabricated with incoherent white light from an incandescent source in LiNbO3:Fe self-defocusing photorefractive crystal for the first time, to our knowledge. It can guide and modulate a probe white light or a laser beam and can be used to transmit an incoherent dark image as the guided modes of the waveguides induced by white-light dark spatial solitons. This also proves the existence of photorefractive nonlinearity of white light.

Self-trapping of incoherent white light

Optical pulses—wave-packets—propagating in a linear medium have a natural tendency to broaden in time (dispersion) and space (diffraction). Such broadening can be eliminated in a nonlinear medium that modifies its refractive index in the presence of light in such a way that dispersion or diffraction effects are counteracted by light-induced lensing1,2. This can allow short pulses to propagate without changing their shape2,3, and the ‘self-trapping’ of narrow optical beams1 whereby a beam of light induces a waveguide in the host medium and guides itself in this waveguide, thus propagating without diffraction4. Self-trapped pulses in space and time have been investigated extensively in many physical systems and, as a consequence of their particle-like behaviour, are known as ‘solitons’ (ref. 5). Previous studies of this phenomenon in various nonlinear media6,7,8,9,10,11,12 have involved coherent light, the one exception being our demonstration13 of self-trapping of an optical beam that exhibited partial spatial incoherence. Here we report the observation of self-trapping of a white-light beam from an incandescent source. Self-trapping occurs in both dimensions transverse to the beam when diffraction effects are balanced exactly by self-focusing in the host photorefractive medium. To the best of our knowledge, this is the first observation of self-trapping for any wave-packet that is both temporally and spatially incoherent.

Selective emitters for thermophotovoltaic power systems for use in aerospace applications

Thermophotovoltaics is the term applied to the technique for energy conversion whereby the energy emitted by an incandescent source is converted to electrical energy by a photovoltaic cell. There are three approaches currently being investigated for practical devices. These are 1) selective filtering, 2) multibandgap conversion, and 3) selective emission. This article will concentrate on selective emission. The selective emitters are made from oxides of the rare Earths such as erbia, holmia, ytterbia, and neodemia. Large area emitters are made through a specialized series of processes that begin with nitrates of the rare Earth and end with rare-Earth oxide filaments. A special requirement for these applications is the need for a robust large area emitter that could take the shock and vibration of space launch or those associated with Army applications. Conventional paper-making techniques have been used to combine materials suitable as binders with the radiating material. As a result, this technique allows the fabrication of large area robust emitters that were heretofore unobtainable. These emitters will be described in some detail, both for fabrication and performance. Nomenclature c{ = first radiation constant, 3.742 x 10 8 W /x,m 4/m2 c2 = second radiation constant, 1.439 x 10 4 //,m K P = power density, W/m2 Px = spectral emissive power/m2/m wavelength interval T = temperature, K e = emissivity A = wavelength cr = Stefan-Boltzmann constant

White-light velocimetry

RADIATION reflected from a moving object experiences a Doppler shift in its frequency. This basic phenomenon underlies practical interferometric techniques for remote velocity measurement used widely in meteorology and law enforcement, as well as in medicine1 (using acoustic waves) and other fields of science and engineering2–5. Existing velocimetric techniques use coherent quasi-monochromatic sources of illumination, which, for optical applications, generally limits practical sources to lasers operating in single-frequency mode. Such sources are not, however, sufficiently powerful for applications where simultaneous velocity measurements at many points on a target are desired. Here we describe a technique for remote velocity measurement that uses broadband incoherent illumination. The viability of this technique is demonstrated by measuring the velocity of a target moving at 16 m s−1 using white light from an incandescent source. Powerful, compact and inexpensive radiation sources (such as flash and arc lamps, or lasers operating at several wavelengths) can now be exploited for high-power applications of remote-target velocimetry.