Spectra In Wavelength Range Research Articles

Application Research of Infrared Technology in Safety Detection in Ship Field

Abstract. This paper studies infrared technology and its application in the field of ship detection, mainly studying infrared thermal imaging of failure equipment refueling oil spill and ship safety problems because infrared technology is a high precision contact thermal measurement method through infrared camera infrared objects, the infrared spectrum wavelength range of infrared radiation heat, on the receiver into electronic signals, through electronic attenuation and electronic scanning form the corresponding heat map or temperature field image, to intuitively reflect the temperature distribution and heat focus of the object. In addition, the infrared detection device can be reasonably installed in the ship without affecting the work of other equipment, and it has been found that infrared technology has significantly improved the solution to the safety problems of ships.

Performance evaluation of a porous polymer-nickel foam compound cooler combining radiative and evaporative cooling

The radiative cooling technology and evaporative cooling technology have drawn intense attentions due to zero energy consumption and negligible carbon footprint, and the afflatus to combine the above two passive cooling technologies has been strongly inspired. The compound cooling mode combining radiative cooling and evaporative cooling can theoretically break through the application limitations under the harsh environmental conditions, but the specific cooling performance needs to be further investigated in conjunction with actual environmental conditions. Herein, a porous polymer-nickel foam (PP-NF) compound cooler is fabricated. The upper porous polymer radiative coating (PPRC) is the radiative cooling layer, and the emissivity is as high as 97% within the atmospheric window (8–13 μm), while the reflectivity is about 98% and 94% in the visible wavelength range (0.38–0.78 μm) and the solar spectrum wavelength range (0.25–2.5 μm), demonstrating remarkable radiative cooling capability. The bottom nickel foam filled with anhydrous calcium chloride (CaCl2) is the evaporative cooling layer, which can absorb water in nighttime to meet the needs of efficient evaporative cooling in daytime. The comprehensive properties of the PP-NF cooler are very impressive for cooling applications, and the outdoor experimental and theoretical results show that the temperature drop and cooling power of the PP-NF cooler can reach 2.7 °C (12:00–13:00) and 100.30 W/m2 (12:00–16:00), which are increased by 42.1% and 24.7% compared to the PPRC cooler with radiative cooling only. Furthermore, the cooling performance of the PP-NF cooler is better than the evaporative cooler in high humidity environment with the relative ambient humidity exceeding 63% through the quantitative analysis of experimental and related theoretical results. The PP-NF cooler has a bright application prospect, and it is very likely to play an indispensable role in the improvement and optimization of the energy framework in the foreseeable future.

Practical considerations of the visible bremsstrahlung inversion (VBI) method for arbitrary EEDF determination in cold atmospheric-pressure plasma

The arbitrary electron energy distribution function (EEDF) of cold atmospheric-pressure plasma is determined from optical emission spectroscopy measurement. Using the electron-neutral bremsstrahlung-dominated continuum spectrum and relevant cross-section data, a partial arbitrary EEDF can be reconstructed through the reinforcement learning-based visible bremsstrahlung inversion method. From an atmospheric-pressure argon dielectric barrier discharge plasma emission spectrum (440–900 nm), a partial arbitrary EEDF can be determined with a resolution of 0.2 eV. The resemblance between the obtained arbitrary EEDF and a two-temperature Maxwellian was found with = 0.26 and 2.2 eV. The EEDF range is mostly constrained by the spectrum wavelength range.

Spectral optical properties of ceramic nanoporous membranes based on anodic aluminium oxide coated silver in ammonia vapors

Spectral optical properties of synthesized ceramic nanoporous membranes based on anodic aluminum oxide coated silver in saturated ammonia gas flow have been experimentally investigated. Based on the measured transmission spectra and detected interference part of the spectra in wavelength range from 550 to 900 nm, temporal and spectral dependencies of the effective optical thickness and its changes in non-equilibrium conditions were obtained due to adsorption of ammonia molecules on silver film surface. According to detected and measured interference maximum shifts up to 14 nm in transmission spectra of Al2O3 + Ag membranes in ammonia gas flow, the possibility of constructing a selective interferometric optical sensors with 10-15 min response time is shown. Keywords: porous anodic aluminium oxide, membrane, silver film, light interference, ammonia vapors, effective optical thickness, interference maximum shift.

Спектральные оптические свойства керамических нанопористых мембран на основе анодного оксида алюминия и покрытия из серебра в парах аммиака

Spectral optical properties of synthesized ceramic nanoporous membranes based on anodic aluminum oxide coated silver in saturated ammonia gas flow have been experimentally investigated. Based on the measured transmission spectra and detected interference part of the spectra in wavelength range from 550 to 900 nm, temporal and spectral dependencies of the effective optical thickness and its changes in non-equilibrium conditions were obtained due to adsorption of ammonia molecules on silver film surface. According to detected and measured interference maximum shifts up to 14 nm in transmission spectra of Al2O3 + Ag membranes in ammonia gas flow, the possibility of constructing a selective interferometric optical sensors with 10 − 15 min response time is shown.

Postharvest ripeness assessment of ‘Hass’ avocado based on development of a new ripening index and Vis-NIR spectroscopy

A classification model using Vis-NIR spectroscopy (380–2000 nm) coupled with partial least square discriminant analysis (PLS-DA) was developed to segregate avocados in three classes, predefined by a warehouse using destructive FF tests performed on a small number of samples. This classification showed a satisfactory general accuracy of 62 %, with 100 % well-classified samples in Class 1, 20 % in Class 2 and 65 % in Class 3. To improve classification, a ripening index (RI) was developed, which combines FF and DMC. The discrimination ability in the three classes was tested using Wilk’s lambda, calculated as between-class variance to the total variance ratio. Results showed values of 0.648 for RI, 0.516 for FF and 0.038 for DMC. A regression model was subsequently developed using Partial Least Squares (PLS) regression to predict RI using Vis-NIR spectroscopy in an independent dataset. The PLS results were satisfactory with the whole spectrum wavelength range (380–2000 nm), with R2 of 0.62, SEP of 0.69 (), but presented a large bias value of 1.22 (). The same occurs in models developed in the wavelength range from 400 to 1100 nm, with R2 of 0.63, SEP of 0.68 () and bias of 1.03 (). This could be corrected using a bias and slope correction algorithm. Study of the correlation coefficients of the PLS regression models showed that the region 400–1100 nm has a huge influence in the model, which indicates the potential of using cost-effective short Vis-NIR spectrophotometers for RI prediction.

Optical properties of CdS:Pb thin layer deposited on glass substrate

The thermal evaporation technique has been used to deposit a polycrystalline cadmium lead sulphide thin film (Cd1-x PbxS with X=0.20) in a vacuum of about 10-5 Torr at 450 °C. This Cd1-x PbxS thin film has been investigated by X-ray diffraction technique. Optical constant like extinction coefficient (K), dielectric constant (€), and refractive index (n) have been measured from transmission spectrum in wavelength range from 700 nm to 1700 nm by manifacier’s envelope method. Crystallite size estimated from the Scherrer method has been found to be 31.25 nm. Coefficient of absorption (α) as well as film thickness (t) has been estimated by means of transmission spectra. The lattice parameter (a), dislocation density (δ), inter planner spacing (d), and micro strain (ε) have been calculated. X-ray study reveals that film stoichiometry is maintained in deposited film. The optical study confirms that optical band gap of Cd1-x PbxS film can be tuned from visible to near infrared region (2.42-1.20 eV) using relatively low cost technique. The red shift in optical band gap has been observed for Cd1-x PbxS thin film. Pb doping increase absorbance in visible region and near infrared region compared to undoped CdS film. The large decrease in band gap has been observed which makes the film much suitable for absorbing layer in solar cells, IR detector and other photovoltaic and optoelectronic applications. In film band, gap of 1.13 eV has been achieved which shows that doping of Pb in CdS makes it suitable material for solar cell absorber and IR detectors. The film shows high transmittance (about 70 %) in near infrared region. The film is polycrystalline and highly stoichiometric.

Thermal and cost analysis of various air filled double glazed reflective windows for energy efficient buildings

The enormous amount of energy is being consumed by buildings in an attempt to deliver thermal comfort in buildings. This paper aims at reducing/increasing the total solar heat gain through various combinations of double glazed reflective windows of buildings. The spectral characteristics of six reflective glasses namely bronze, green, grey, opal blue, sapphire blue and gold-reflective glasses at a normal angle of incidence by using UV-3600 Shimadzu spectrophotometer according to ASTM E 424 standards were experimentally measured. The solar optical properties of the glasses were deduced by developing a MATLAB code using spectral data which was obtained from experiments in the solar spectrum wavelength range of 300 nm–2500 nm. Thirty air-filled double-glazed reflective windows have been studied for both thermal and cost analysis in the Indian composite climatic zone (New Delhi 28.580 N, 77.200 E). The configuration C13 (Grey reflective glass-Air gap 10 mm-Gold reflective glass) is observed to be the best air-filled double glazed window from the highest annual cost savings ($ 79.29 per annum in SE direction) and lower payback period (1.42 years) point of views among thirty double-glazed reflective glasses studied. The results of this paper are useful in the design of sustainable passive solar buildings.

Study Effect of Annealing on Optical Constants of (As0.5Se0.5 doped with Te at 1%) Thin Films

In this work, thin films of (As0.5Se0.5 doped with Te at 1%) were prepared by thermal vacuum evaporation on glass bases in (R.T) with (100±20)nm thickness deposition rate (1.6nm/s) and study effects of annealing temperature (Ta) (348,398,448)K for time (30min) on optical constants for prepared films. The X-ray diffraction technique showed that all prepared films are amorphous in structure at room temperature and annealing films at (348, 398,448)K. The optical constants (refractive index (n0), extinction coefficient (K0), dielectric constant (∈r)) evaluated from transmission spectra in wavelength range (500-1100)nm and found that it increase with the increasing of (Ta) for the prepared films.

Monitoring the kinetics of reactions between natural organic matter and Al(III) ions using differential absorbance spectra

This study examined the kinetics of the binding of Al(III) ions by natural organic matter (NOM) exemplified by Suwannee River humic acid (SRHA). This processes was studied for a 5–8 pH range and environmentally relevant concentrations of the system components. Al(III)-NOM interactions were quantified using differential absorbance spectra whose intensity and shape depended on pH and reaction time. In all cases the differential spectra had four bands with maxima located at 245, 275, 320, 380 nm. These bands were assigned to the engagement of the carboxylic-like and/or phenolic-like groups, as well as electrostatic gel in NOM. Several parameters of the absorbance spectra (e.g., spectral slopes of log-transformed spectra in wavelength range 260–270 and 350–400 nm, ΔS260-270 and ΔS350-400 respectively) were linearly correlated (R2 = 0.98) with concentrations of carboxylic-like groups and total NOM-bound Al(III) ions predicted based on the NICA-Donnan model. The binding of Al(III) ion by NOM at all pHs was modeled assuming the presence of three kinetically distinct sites. This study demonstrates that differential absorbance spectroscopy can be used to quantify the kinetics and mechanisms of NOM-metal ions interactions and monitor them in practically important system including water treatment operations.

Optical, electrical and photoelectrical properties of nanocrystalline cadmium selenide films for photosensor applications

In this work, CdSe powder was synthesized by using an aqueous route in the presence of polyethylene glycol as a surfactant. The as-prepared powder was used to prepare different film thickness (101–179 nm) using thermal evaporation technique. The structural, optical, electrical and photoelectrical properties of the films have been reported. The structural properties of the films were studied by X-ray diffraction and high-resolution transmission electron microscope techniques. The films were found to have nanostructure nature in which the particle size increases with increasing film thickness. The optical properties of the films were investigated using transmittance and reflectance spectra in wavelength range 200–2500 nm. The optical band gap of the films was determined as a function of film thickness and showed high band gap compared to bulk material due to quantum size effect. The refractive index was also calculated and analyzed in which the dispersion parameters were determined. The electrical resistivity was found to decrease with increasing film thickness due to size effect. Under illumination, the resistance of the films was found to decrease in which the films are promising candidates for photosensor applications.

A bench-top hyperspectral imaging system to classify beef from Nellore cattle based on tenderness

The aim of this study was to evaluate the accuracy of classification of Nellore beef aged for 0, 7, 14, or 21 days and classification based on tenderness and aging period using a bench-top hyperspectral imaging system. A hyperspectral imaging system (λ = 928–2524 nm) was used to collect hyperspectral images of the Longissimus thoracis et lumborum (aging n = 376 and tenderness n = 345) of Nellore cattle. The image processing steps included selection of region of interest, extraction of spectra, and indentification and evalution of selected wavelengths for classification. Six linear discriminant models were developed to classify samples based on tenderness and aging period. The model using the first derivative of partial absorbance spectra (give wavelength range spectra) was able to classify steaks based on the tenderness with an overall accuracy of 89.8%. The model using the first derivative of full absorbance spectra was able to classify steaks based on aging period with an overall accuracy of 84.8%. The results demonstrate that the HIS may be a viable technology for classifying beef based on tenderness and aging period.

Extraction of Spectral Information from Hyperspectral Data and Application of Hyperspectral Imaging for Food and Agricultural Products

Hyperspectral imaging is built with the aggregation of imaging, spectroscopy and radiometric techniques. This technique observes the sample behaviour when it is exposed to light and interprets the properties of the biological samples. As hyperspectral imaging helps in interpreting the sample at the molecular level, it can distinguish very minute changes in the sample composition from its scatter properties. Hyperspectral data collection depends on several parameters such as electromagnetic spectrum wavelength range, imaging mode and imaging system. Spectral data acquired using a hyperspectral imaging system contain variations due to external factors and imaging components. Moreover, food samples are complex matrices with conditions of surface and internal heterogeneities, which may lead to variations in acquired data. Hence, before extracting information, these variations and noises must be reduced from the data using reference-dependent or reference-independent spectral pre-processing techniques. Using of the entire hyperspectral data for information extraction is tedious and time-consuming. In order to overcome this, exploratory data analysis techniques are used to select crucial wavelengths from the excessive hyperspectral data. Using appropriate chemometric techniques (supervised or unsupervised learning techniques) on this pre-processed hyperspectral data, qualitative or quantitative information from sample can be obtained. Qualitative information for analysing of the chemical composition, detecting of the defects and determining the purity of the food product can be extracted using discriminant analysis techniques. Quantitative information including variation in chemical constituents and contamination levels in food and agricultural sample can be extracted using categorical regression techniques. In combination with appropriate spectra pre-processing and chemometric technique, hyperspectral imaging stands out as an advanced quality evaluation system for food and agricultural products.

Incident ion charge state dependence of the visible light emission of Xeq+ ions bombarding aluminum

AbstractIn this work, we studied the photon emission in the visible light range for Xeq+ ions of different charge states (10 ≤ q ≤ 21) bombardment on an aluminum target at 410 keV. During the interactions, the spectra in wavelength range 300–500 nm are recorded, including the photons from Al atoms and neutralized Xe+ ions. The yield of the visible light strongly depends on the projectile charge states. Its variation tendency with the charge states is similar to that of the potential energy variation. In addition, the experimental results also indicate that when the incident charge state is less than the critical charge state, it obeys the staircase classical-over-barrier model.

Deposition and characterisation of spray-deposited nanocrystalline Cd1−XZnXS thin films for photovoltaic device applications

Nanocrystalline Cd1−XZnXS thin films (X = 0.2, 0.4, 0.6, 0.8) have been grown on glass substrate by spray pyrolysis technique using equimolar concentration aqueous solution of cadmium chloride, zinc acetate and thiourea. Prepared thin films have been characterised by UV–vis spectrophotometer, X-ray diffractometer, SEM/EDAX analysis and two-point probe set-up. The optical band gap of the films has been studied by transmission spectra in wavelength range 325–600 nm. It has been observed that optical band gap increases with increasing zinc concentration. The X-ray diffraction pattern of films indicated that the films are polycrystalline with hexagonal grain structure. The lattice parameters of prepared Cd1−XZnXS films decrease with increase in zinc content. SEM/ EDAX analysis consolidates the formation of ternary compound. The DC electrical conductivity and activation energy of the films has been measured in vacuum by a two-point probe set-up. It has been observed that the electrical conductivity decreases with increasing Zn concentration in films.

Wireless InGaN–Si/Pt device for photo-electrochemical water splitting

We demonstrate a wireless device comprising a gallium nitride (GaN)–silicon-based photo-electrode, and a platinum cathode. Compared with conventional two-electrode photo-electrochemical systems, this wireless monolithic device showed potential for a wider range of applications, and reduced the resistance losses resulting from the wiring and aqueous solution. The efficiency was improved when the electrolyte was changed from KHCO3 to NaOH because water oxidation capability of the surface of the GaN was enhanced. A wider solar spectrum wavelength range was exploited by adopting InGaN as a photo-absorption layer; the improved efficiency for hydrogen generation was 0.90%.

Growth and characterization of Cd0.8Zn0.2S thin films by spray pyrolysis method

Sulphides of zinc and cadmium have been utilized effectively in various opto-electronic devices. Cd0.8Zn0.2S thin films have been deposited on glass substrate by the conventional spray pyrolysis method. The structural, optical and electrical properties have been investigated through the X-ray diffractometer; UV–vis spectrophotometer and Keithley two probe set up. The X-ray diffraction pattern of films show that the films are polycrystalline in nature exhibiting hexagonal structure with preferential orientation along the (002) plane. The optical band gap of the films has been studied by using transmission spectra in wavelength range 325–600nm. The DC electrical conductivity of the films has been measured in vacuum by a two probe technique.

Determination of the Carbonyl Values for Frying Rapeseed Oil Using Near-Infrared Spectroscopy

Near-infrared (NIR) spectroscopy was investigated as a method for analysis of the carbonyl value (CV) in frying oils. Two types of rapeseed oil were used to fry potatoes and 156 samples of frying oil were obtained. Transmission spectra of the samples were acquired directly using glass test tubes (13-mm diameter) as sample cells and an NIR spectrometer. Calibration models with very high accuracy based on the second derivative spectra in wavelength range of 1100–2200 nm were developed for predicting the CV using partial least-squares regression with full cross-validation. The coefficients of determination for calibration and standard error of cross-validation were 0.98 and 1.79 μmol g−1, respectively. The accuracy of the NIR calibration models was tested using the validation set, yielding the value for the root mean square of the prediction as 1.74 μmol g−1. The results demonstrate that the CV for frying oils can be accurately determined using NIR spectroscopy.

High Performance ZnO-SnO2:F Nanocomposite Transparent Electrodes for Energy Applications

Enhancing the propagation length of light without sacrificing the electro-optical properties of transparent electrodes is of particular interest to solar cells for reaching higher efficiency. This can typically be achieved by nanostructured electrodes but all too often at the expense of complexity and cost-effectiveness. In this work, we demonstrate the simple and low-cost fabrication of a new type of ZnO-SnO2:F nanocomposite thin film by combining spin-coated ZnO nanoparticles on glass with fluorine-doped SnO2 thin films deposited by atmospheric spray pyrolysis. The resulting nanocomposites exhibit a dual surface morphology featuring rough ZnO-SnO2:F nanostructures along with the original smooth SnO2:F thin film. By readily modulating the surface morphology of ZnO-SnO2:F nanocomposite thin films with the initial ZnO NP surface coverage, the scattering efficiency of the incident light can remarkably be controlled over the 400-1100 nm solar spectrum wavelength range. High quality hazy ZnO-SnO2:F thin layers are therefore formed with an averaged haze factor ranging from 0.4 to 64.2% over the 400-1100 nm solar spectrum range while the sheet resistance is kept smaller than 15 Ω/sq for an average total optical transmittance close to 80%, substrate absorption and reflection included. Eventually, optical simulations using Fourier transform techniques are performed for computing the obtained haze factors and show good agreement with experimental data in the 400-1100 nm solar spectrum wavelength range. This opens up additional opportunities for further design optimization of nanoengineered transparent electrodes.

Optimization of Anti-reflection Coating for Improving the Performance of GaAs Solar Cell

The objective of this work is to reduce the front surface reflectivity of the GaAs solar cell by depositing AR-coating of appropriate thickness and refractive index material. We use MgO and ZnO film and optimize their thickness for minimum reflectivity. Results indicate that the reflectivity is reduced up to 4% for MgO film and 2% for ZnO film at solar spectrum wavelength range from 550 nm to 650 nm. The external efficiency of GaAs solar cell with AR-coating is increased by 31.53% and 33.09% for MgO and ZnO film respectively.