Bands Of AlO Research Articles

Functionalization and Deconvolution of Tubular Ceramic Support Membrane Prepare from High Silica Spent Bleaching Earth by Centrifugal Casting

Spent Bleaching Earth (SBE) is a solid waste produced from the palm cooking oil refining industry. The commercial ceramic membranes are quite pricey, therefore SBE solid waste is possible to be an alternative for reduction of membrane material cost due to high silica content. This work demonstrates the fabrication of ceramic tubular support membrane with varied SBE addition and investigates the functionalization group of its membranes. The ceramic support membrane was prepared from regeneration SBE with varied loading composition 15 and 35 wt%. The regeneration SBE using n-Hexane as solvent. Membranes were casted into tubular configuration using centrifugal casting technique at 3000 rpm. The tubular ceramic SBE membranes were dried and followed by calcined at 900°C with heating rate 2°C/min using programable furnace for 2 h. Both of raw SBE material and membranes were analyzed using Fourier transform infrared (FTIR). The SBE material after regenerated exhibits has high Si-OH and Si-O-Si peaks over raw material. Interestingly, the fabrication ceramic support membrane with tubular configuration is successfully preparation by centrifugal casting. Ceramic SBE membrane exhibits functionalization and deconvolution the present of siloxane, Al-OH-Al, Ti-O-Ti, and Al-O bands for both of 15 and 35wt% SBE loading. It concluded this tubular ceramic support membrane from SBE has appropriated chemical functionalize properties to applicates as membrane separation.

Assessment of toxicity of residues of normal/green cracker and their impact on soil

In the present work, laser-induced breakdown spectroscopy (LIBS) is used to examine the hazardous constituents present in the residues of six types of normal and six types of green firecracker samples. The residue of the normal firecracker’s samples contains the spectral lines of toxic chemicals such as Al, Ba, Sr, Mg, and Ti in a similar way as the fresh powder of normal crackers. The residues of the green firecracker’s samples contain toxic elements such as Al and Ba, and the intensities of these toxic elements are so high that these samples also contain the electronic bands of AlO and SrO. The UV-vis spectra of residues of normal and green firecracker samples contain the molecules of KNO3, CaO, Al2O3, and SrO in a similar way as the fresh powder of these firecrackers does. This reflects that the toxicity of the powder of firecracker samples remains similar after the burning of these firecrackers’ samples. Therefore, these toxic residues are mixed in the soil, where they burn and contaminate it. For the assessment of the contamination of the soil, the concentration of micronutrients such as Fe, Cu, Mn, Zn, and P is calculated using atomic absorption spectroscopy (AAS) techniques and found to increase in all the contaminated soil compared to blank soil. This reflects that the soil is contaminated. For the classification of the residues and soil contaminated with residues, the principal component analysis (PCA) and hierarchical clustering analysis (HCA) are applied to the LIBS data set.

Assessment of the terminal velocity of explosively-propelled metal liner using laser-induced breakdown spectroscopy

ABSTRACT Organic energetic compounds containing aluminum (OECAl) are hazardous materials, which have extensive applications in industries. For military and commercial high explosives, Gurney velocity is the terminal velocity of explosively-propelled metal liner on the bases of the ratio of the mass of metal to the mass of explosive. Due to the high cost of experimental determination of Gurney velocity, it is suitable to have a low-cost experimental method for reliable estimation of Gurney velocity of OECAl. A novel approach is introduced to use laser-induced breakdown spectroscopy (LIBS) as a highly energetic laser pulse to atomize and excite samples (a plasma) for assessment of the Gurney velocity of OECAl. Five compositions of 1,3,5-trinitro-1,3,5-triazine (RDX)-based aluminized explosives are studied through the LIBS technique to detect their atomic and molecular emissions in the air atmosphere. Plasma emissions of these compositions are recorded where the atomic line of Al as well as molecular bands of AlO and CN have the highest intensities at some wavelengths. Intensities of Al (λ = 394.38 and 396.16 nm), CN (λ = 388.29 and 422.70 nm), and AlO (λ = 467.19, 484.25, and 464.84 nm) peaks are correlated with their Gurney velocities. The intensity of Al at 396.16 nm gives the best linear relationship (r2 = 0.981) with the Gurney velocity of OECAl samples.

LIBS at high duty-cycles: effect of repetition rate and temporal width on the excitation laser pulses

Laser-induced breakdown spectroscopy (LIBS) is becoming a more mature technology every year with new variants such as laser ablation molecular isotopic spectrometry, reheating by various discharge techniques, and multiple pulse excitation schemes, in which sometimes lasers of different pulse lengths are used. However, lasers with inherent parameters like pulse length and repetition rate are still almost exclusively employed. Recent years have witnessed the advent of novel high-repetition-rate laser concepts for machining processes, like welding, milling, and engraving. Here, a comprehensive study of single-pulse LIBS spectra of a single aluminum target is presented to showcase the applicability of flexible high duty-cycle master oscillator power amplifier (MOPA) lasers. Although traditional flashlamp-pumped Fabry–Pérot lasers only permit a variation in the pulse energy and are operated at very low duty-cycles, MOPA lasers add repetition rate and pulse length as variable parameters. A thorough analysis of the temporal plasma behavior revealed the emission dynamic to closely match the excitation laser pulse pattern. An aluminum sample’s spectral response was shown to be significantly impacted by variations in both rate and length. Although the spectral emission strength of the elemental lines of Al, Sr, and Ca all peaked at slightly different parameter settings, the strongest impact was found on the relative abundance of molecular AlO bands. Unlike in previous laser ablation molecular isotopic spectrometry (LAMIS) publications, the latter could be readily detected with a good intensity and well-resolved spectral features without any temporal gating of the detector. This finding, together with the fact that MOPA lasers are both inexpensive and dependable, makes for a promising combination for future studies including the detection of diatomic band structures.

Effect of atmospheric pressure pulsed discharge spatial inhomogeneity on Ar I and H I lines: Electron number density study

AbstractThe spatial inhomogeneity of pulsed atmospheric pressure discharge in argon is investigated using the electron number density Ne diagnostics procedure applied to asymmetrically broadened Ar I lines. A dedicated fitting procedure is used for describing Ar I 703.0 nm line shape recorded from argon gas discharge and H I (at 486.13 and 656.28 nm) lines recorded from Ar‐H2 gas mixture discharge. The results revealed the change in Ne in both axial and radial directions. The additional Ar I lines at 614.5, 710.7, 731.2, and 731.6 nm, recorded from integral spatial radiation, are analysed as well to confirm the results from the plasma column region. The possibility of using AlO (B2∑+–X2∑+) and CN (B2∑+–X2∑+) molecular bands for gas temperature Tg measurements in this type of gas discharge source is demonstrated and Tg used as an input parameter for the Ne diagnostics procedure. For the proper identification of molecular band spectral lines, the Fortrat parabolas are constructed. The results obtained from Ar I 703.0 nm line indicate three different Ne values, with Ne1 ≈ 0.6 × 1016 cm−3, Ne2 ≈ 3.6 × 1016 cm−3, and Ne3 ≈ 19 × 1016 cm−3 measured from the plasma column. These Ne values increase in the cathode and anode region.

Investigation of Hazardous Materials in Firecrackers using LIBS Coupled with a Chemometric Method and FTIR Spectroscopy

This article reports the detection and quantification of toxic constituents in firecrackers using LIBS coupled with PCA and FTIR. Spectral signatures of lethal elements along with other elements and electronic bands of Cyanide, AlO, BaO, and CaO are seen in their LIBS spectra which confirms the presence of inorganic and organic compound in the fireworks. The concentration of each constituent/element is determined using the CF-LIBS method and results are compared with ICP-OES results. The concentration of Al is in adequate amount except S4 (b). Li and Ba are present in all samples with maximum amount in S4 (b) and S3 respectively. Molecular stretching of SO4-, C4 H8 - , CuCl- , CO3 - , and NO3 - are observed in the FTIR spectra of the samples. The combined results of LIBS and FTIR recommends the presence of BaNO3 , LiCO3 , SrCO3 , Al-chip, and charcoal in the firecrackers. To discriminate various firecrackers, PCA of the LIBS data is performed. The results show that S3 and S4 (b) are more harmful as they contain higher concentration the compounds of Al, Ba, Li, Sr i.e BaNO3 , LiCO3 , SrCO3 , (Cu3 As2 O3 Cu(C2 H3 O2 )2 ).

Optical properties of alumina films by sol gel acrylamide route

A new acrylamide route was applied to prepare alumina films by using aluminum chloride as a starting material and ammonium persulphate solution as the gelling agent. The XRD results show that the films are amorphous for the post anneals temperatures up to 300 °C, beyond this temperature; peaks corresponding to γ-Al2O3 are observed. XPS studies indicated the peaks corresponding to the Al 2p spectra of films after annealing at different temperatures. The FTIR spectra reveal absorption bands of Al-O and to lattice. The absorption co-efficient was 1014 cm- 1.Refractive index was in the range of 1.71 to 1.61 with increase of wavelength from 250-500 nm. Optical band gap value was around 5.40-5.75 eV with increase of annealing temperature.

Rapid Elemental Determination And Discrimination Of Coins Using Laser-Induced Breakdown Spectroscopy

Damaged coins can be identified effectively via spectral analysis based on LIBS, which is of great significance for coin recycling. This paper takes the Renminbi (RMB), the Chinese currency, as the example, including the denominations of YI FEN, ER FEN, WU FEN, YI JIAO, WU JIAO and YI YUAN. Some characteristic lines of Mg, Al, Fe, Cr, Cu, Sn, Ni, Na and Ca were observed in the spectra, as well as the molecular bands of AlO. Principal component analysis (PCA) was used to reduce the dimension of the spectra of the different RMB coins. The samples after dimension reduction are classified by k-Nearest Neighbors (KNN), and 4 categories were obtained with a classification accuracy of 100%. Further, new spectra of different denomination RMB coins were added to the original data for the same analysis. The results are in good agreement which shows the potential of the combination of LIBS, PCA and KNN for the analysis and identification of different coins.

Optical emission study of plasma vortex rings at atmospheric pressure air

The article presents the results of high-speed spectral measurements of the emission spectrum of plasma-vortex formations formed by an atmospheric pulsed plasma torch based on an electrical explosion of a conductor. Spectrum registration is carried out in the stage of autonomous existence of vortex formations. It is shown that the emission spectrum contains the Planck continuum, due to the presence of condensed oxides, and the molecular bands of AlO. Based on the obtained data, the dependence of the temperature dynamics over time was obtainedby the method of spectral pyrometry.

Sensing Enhancement on ZnO Nanorod Gas Sensors with Novel Nanorod/Nanotube Structures

Among various Metal Oxide Semiconductor (MOS) materials for in gas sensor applications, ZnO has been widely used in gas detection due to its wide band gape of 3.37 eV, large exciton binding energy (~60 meV), good electrical conductivity, and high mechanical stability. Moreover, owning to the high surface-to-volume ratio, ZnO gas sensors based on nanorod structure are extensively applied into gas specie detection and gas concentration detection. Therefore, a large number of methods and techniques have been applied to enhance the sensing performance of ZnO nanorod gas sensors. In this work, the ZnO nanorods with coaxial nanotubes gas sensors were fabricated to detect the concentration of ethanol vapor under the different temperatures and concentration conditions. In addition, Al doped ZnO (AZO) thin films were deposited on the surface of ZnO nanorods by Atomic Layer Deposition (ALD). The additional oxygen vacancies deficiency from the Zn-O and Al-O bands in the Zn-Al-O interface could improve the sensing performance of prepared ZnO gas sensors. In this study, ZnO nanorods were synthesized by hydrothermal method with ZnO seed layers deposited on Si wafer by ALD, as shown in Figure 1(a). The solutions used for ZnO nanorods hydrothermal growth were prepared with zinc nitrate hexahydrate (Zn(NO3)6H2O) and hexamethylenetetramine ((CH2)6N4) dissolved in DI water. To synthesize ZnO nanotubes around nanorods, one additional Al2O3 sacrificial layer was deposited on the surface of ZnO nanorods by ALD with TMA (Al2(CH3)6) and DI water as precursors. Then ZnO thin films were deposited on ZnO nanorods with Al2O3 sacrificial layer wrapped around, as shown in Figure 1(b). To eliminate the sacrificial layer, Precision Ion Polishing System (PIPS) was used to remove the top cover of ZnO nanorods. Figure 1(c) and Figure 1(d) show the Al2O3 sacrificial layer was exposed for Sodium hydroxide (NaOH) etching. After the sacrificial layer was removed by NaOH, ZnO nanorod/nanotube gas sensors were synthesized, as shown in Figure 1(e). To further enhance the sensing performance of ZnO nanorod/nanotube to the ethanol, AZO thin films were deposited on the surface by ALD as shown in Figure 1(f). A testing system of gas sensors was developed with a sealed reaction chamber and control system based on CompactRio from National instrument to investigate the sensing performance of ZnO nanorod/nanotube to ethanol vapor. The sensing response of ZnO nanorods to ethanol vapor was recorded and analyzed from the resistance change of ZnO nanorods. The sensing performances of ZnO nanorods, ZnO nanorod/nanotube, and ZnO nanorod/nanotube after coated with AZO thin films were measured and analyzed under various volumes of ethanol vapor at different temperatures. Base on the results, the sensing performance of ZnO nanorod gas sensor was enhanced by increase surface-to-volume ratio and oxygen vacancies. Figure 1. FESEM results of (a) ZnO Nanorods, (b) ZnO Nanorods with Al2O3 Coating and ZnO thin films, (c) and (d) Al2O3 sacrificial layer exposed after PIPS, (e) ZnO Nanorod/Nanotube after NaOH Etching, (f) ZnO Nanorod/Nanotube with AZO Coating. Figure 1

Quantitative analysis for the determination of aluminum percentage and detonation performance of aluminized plastic bonded explosives by laser-induced breakdown spectroscopy

The aluminized plastic-bonded explosive (PBX) is a composite material in which solid explosive particles are dispersed in a polymer matrix, which includes three major components, i.e. polymeric binder, metal fuel (aluminum) and nitramine explosive. This work introduces a new method on the basis of the laser-induced breakdown spectroscopy (LIBS) technique in air and argon atmospheres to investigate the determination of aluminum content and detonation performance of aluminized PBXs. Plasma emissions of aluminized PBXs are recorded where atomic lines of Al, C and H as well as molecular bands of AlO and CN are identified. The experimental results demonstrate that a good discrimination and separation between the aluminized PBXs is possible using LIBS and principle component analysis, although they have similar atomic composition. Relative intensity of the AlO/Al is used to determine aluminum percentage of the aluminized PBXs. The obtained quantitative calibration curve using the relative intensity of the AlO/Al is better than the resulting calibration curve using only the intensity of Al. By using the LIBS method and the measured intensity ratio of CN/C, an Al content of 15% is found to be the optimum value in terms of velocity of detonation of the RDX/Al/HTPB standard samples.

Synergistic behaviors of anthracite and dried sawdust sludge during their co-combustion: Conversion ratio, micromorphology variation and constituents evolutions

This paper studied the synergistic behaviors of anthracite and dried sawmill sludge (DSS) in the conversion ratio (CR) of combustible substances, micromorphology variation and constituents' evolutions. The results showed that the blend CRs were the highest, and CRs increased with O2 and temperature. In ash formation, DSS mainly contributed to the fly ash yield, while anthracite determined the morphology of bottom ash. The carbon proportion of combusted blend decreased to 0, revealing its thorough combustion, thereby proving the synergistic effects between anthracite and DSS. The disappearances of CC, CH2 and OH determined by FT-IR indicated the burning losses of kinds of hydrocarbons, meanwhile the identified enlarged bands of SiO, AlO and FeO suggested the formations of inorganic compounds. The XRD results further demonstrated the formations of SiO2, Al2O3, CaSO4 and Fe2O3, the rising temperature promoted their melting/conglomeration process, thereby lowering the XRD peaks since the mischcrystals generations. The oxygen-enrich atmosphere inhibited the formations of SiO2 and Al2O3 but promoted the generation of Fe2O3, and accelerated the formation of porous-smooth ash. The addition of CaCO3 assisted the pore formation and integrated the metal-oxides crystals. Urea made the particles welly dispersed, and weakened the XRD peaks since it improved the melting process.

The CaO orange system in meteor spectra

The CaO orange band system was simulated in the region 5900–6300 Å and compared with the experimentally observed spectra of Benešov bolide wake. The required vibronic Einstein emission coefficients were estimated by means of the experimental radiative lifetimes under the simplest Franck-Condon approximation. A moderate agreement was achieved, and the largest uncertainties come from modeling shape of FeO orange bands. Using a simple model the CaO column density in the wake of the Benešov bolide at the height of 29 km was estimated as (5 ± 2) × 1014 cm−2 by a comparison of the present CaO spectra with the AlO bands nicely observed at 4600–5200 Å in the same spectrum. The obtained CaO content is in a good agreement with the quenching model developed for the impact-produced cloud, although future theoretical and experimental studies of both CaO and FeO orange systems contribution would be needed to confirm these results.

An inexpensive technique for the time resolved laser induced plasma spectroscopy

We present an efficient and inexpensive method for calculating the time resolved emission spectrum from the time integrated spectrum by monitoring the time evolution of neutral and singly ionized species in the laser produced plasma. To validate our assertion of extracting time resolved information from the time integrated spectrum, the time evolution data of the Cu II line at 481.29 nm and the molecular bands of AlO in the wavelength region (450–550 nm) have been studied. The plasma parameters were also estimated from the time resolved and time integrated spectra. A comparison of the results clearly reveals that the time resolved information about the plasma parameters can be extracted from the spectra registered with a time integrated spectrograph. Our proposed method will make the laser induced plasma spectroscopy robust and a low cost technique which is attractive for industry and environmental monitoring.

Approach for determination of detonation performance and aluminum percentage of aluminized-based explosives by laser-induced breakdown spectroscopy.

Energetic materials containing aluminum powder are hazardous compounds, which have wide applications as propellants, explosives, and pyrotechnics. This work introduces a new method on the basis of the laser-induced breakdown spectroscopy technique in air and argon atmospheres to investigate determination of aluminum content and detonation performance of 1,3,5-trinitro-1,3,5-triazine (RDX)-based aluminized explosives. Plasma emission of aluminized RDX explosives are recorded where atomic lines of Al, C, H, N, and O, as well as molecular bands of AlO and CN are identified. The formation mechanism of AlO and CN molecular bands is affected by the aluminum percentage and oxygen content present in the composition and plasma. Relative intensity of the Al/O is used to determine detonation velocity and pressure of the RDX/Al samples. The released energy in the laser-induced plasma of aluminized RDX composition is related to the heat of explosion and percentage of aluminum.

Unexpected temporal evolution of atomic spectral lines of aluminum in a laser induced breakdown spectroscopy experiment

The temporal evolution of the laser induced breakdown (LIBS) signal of a pure aluminum sample was studied under nitrogen and air atmospheres. In addition to the usual decrease of signal due to plasma cooling, unexpected temporal evolutions were observed for a spectral lines of aluminum, which revealed the existence of collisional energy transfer effects. Furthermore, molecular bands of AlN and AlO were observed in the LIBS spectra, indicating recombination of aluminum with the ambient gas. Within the experimental conditions reported in this study, both collisional energy transfer and recombination processes occurred around 1.5μs after the laser shot. This highlights the possible influence of collisional and chemical effects inside the plasma that can play a role on LIBS signals.

Structural and photoluminescence study of Mn2+‐activated CaYAl3O7 blue phosphors

The structural and photoluminescence properties of CaYAl3 O7 phosphor material doped with varying concentration of Mn(2+) have been studied. The phosphor material was synthesized by the combustion method at 500 °C and was characterized using X-ray diffraction, Fourier transform infrared spectroscopy and photoluminescence spectroscopy (PL). X-ray diffraction showed that the crystallites have average sizes in the range of ~58-70 nm. Corresponding Fourier transform infrared spectroscopy investigations confirm the phase formation and the presence of aluminate group (Al-O bands) in CaYAl3 O7 :Mn(2+) phosphor. Under the excitation at 356 nm wavelength, the PL spectra show the occurrence of two emission peaks obtained in the blue region at 389 nm and 412 nm, which is attributed to the 4 T1(G) → 6A1 transition of Mn(2+) ion. Upon increasing Mn(2+) concentration, the relative PL intensity shows an initial decrement followed by an increase displaying the effect of concentration quenching. Overall the results suggest the possibility of using this material in white lighting devices and plasma display panels.

Aluminium oxide in the optical spectrum of VY Canis Majoris

We report the first identification of the optical bands of the B-X system of AlO in the red supergiant VY CMa. In addition to TiO, VO, ScO, and YO, which were recognized in the optical spectrum of the star long time ago, AlO is another refractory molecule which displays strong emission bands in this peculiar star. Simulating the bands of AlO, we derive a rotational temperature of the circumstellar gas of Trot=700K. By resolving individual rotational components of the bands, we derive the kinematical characteristics of the gas, finding that the emission is centered at the stellar radial velocity and its intrinsic width is 13.5 km/s (full width at half maximum). It is the narrowest emission among all (thermal) features observed in VY CMa so far. The temperature and line widths suggest that the emission arises in gas located within ~20 stellar radii, where the outflow is still being accelerated. This result contradicts equilibrium-chemistry models which predict substantial AlO abundances only to within a few stellar radii. We argue that non-equilibrium models involving propagation of shocks are needed to explain the observations.

THE A-X INFRARED BANDS OF ALUMINUM OXIDE IN STARS: SEARCH AND NEW DETECTIONS

We describe a search for the A-X infrared bands of AlO with a view to better understand the characteristics of this radical. These bands are infrequently encountered in astronomical sources but surprisingly were very prominent in the spectra of two well-known, nova-like variables (V838 Mon and V4332 Sgr) thereby motivating us to explore the physical conditions necessary for their excitation. In this study, we present the detection of A-X bands in the spectra of 13 out of 17 stars, selected on the basis of their J-K colors as potential candidates for detection of these bands. The majority of the AlO detections are in AGB stars viz. 9 OH/IR stars, 2 Mira variables and 2 bright infrared sources. Our study shows that the A-X bands are fairly prevalent in sources with low temperature and O-rich environments. Interesting variation in strength of the AlO bands in one of the sources (IRAS 18530+0817) is reported and the cause for this is examined. Possible applications of the present study are discussed in terms of the role of AlO in alumina dust formation, the scope for estimating the radioactive $^{26}$Al content in AGB stars from the A-X bands, and providing possible targets for further mm/radio studies of AlO which has recently been discovered at millimeter wavelengths.

The effect of a shock wave on the ignition behavior of aluminum particles in a shock tube

The effect of a shock wave on the ignition behavior of 5 μ m aluminum (Al) particles was studied in a series of experiments by means of a horizontal shock tube with an inner diameter of 70 mm. To isolate the shock effect from other effects, the experiments were conducted in an inert argon (Ar) atmosphere in addition to a few control experiments in air. The use of Ar as driven gas also helps to produce strong shocks. Every aluminum particle is initially covered with a layer of amorphous aluminum oxide (Al 2O 3). The Al 2O 3 passivates the particle, thus playing a key role in the ignition and combustion mechanisms of an Al particle. The experiments showed a strong emission of light originating from the particles immediately after the shock wave has passed them. Spectral analysis revealed strong AlO bands even in experiments in which the volatilization temperature of Al 2O 3 was not exceeded. The emission spectrum of the flame permits the determination of a grey-body temperature. The existence of AlO molecules and the analysis of samples taken after an experiment give a strong evidence of the influence of a shock wave on the ignition and reaction mechanism of Al particle combustion.