CH Bands Research Articles

Rapid evaluation of fat content in curry soup containing coconut milk by using near infrared spectroscopy

The feasibility of a near infrared spectroscopy to evaluate the fat content in instant curry soup containing coconut milk including green curry, red curry, massaman curry and panang curry was investigated. The soup samples were collected from a processing line and as the finished product. There were also fat content-adjusted samples where the curry was made from the same recipe as in the processing line but increasing by 30, 60 and 90% coconut milk and reducing by 30, 60 and 90% coconut milk from normal. A Fourier transform near infrared spectrometer was used to collect scans. A partial least squares regression model for fat content was established using near infrared spectral data in conjunction with reference data, which was validated using a leave-one-out cross-validation and test set validation. The test set validation, using a set of unknown samples, showed better prediction performance. The best model developed using vector normalization spectral pre-treatment on 9404–7498 and 6102–5446 cm−1 provided coefficient of determination, root mean square error of prediction, bias and ratio of performance to interquartile values of 0.90, 0.9%, −0.1% and 1.2, respectively, for the validation samples. However, the model developed using samples without fat content adjusted samples gave a slightly lower coefficient of determination (0.89), but provided a lower root mean square error of prediction (0.5%) and acceptable ratio of standard error of validation to the standard deviation (3.2). In addition, the vibration bands of CH2 which was in the long chain fatty acid moiety highly influenced the prediction of fat content in the curry soup. The near infrared spectroscopy protocol developed for the determination of fat could be applied in the instant curry soup production line.

A simplified approach to simultaneous multi-scalar imaging in turbulent flames

This communication describes and demonstrates an approach to making simultaneous multi-scalar measurements with reduced equipment requirements. Specifically, this letter describes and demonstrates the ability to simultaneously acquire high-quality planar laser-induced fluorescence (PLIF) images of CH2O and either CH, OH, or a combination of CH and OH using a single Nd:YAG-pumped dye-laser system and two intensified cameras. Acquiring these images with common diagnostic equipment was facilitated by exciting strong transitions in the C–X (0,0) band of CH (near 314 nm) and in the A–X (0,0) and (1,1) bands of OH, which are spectrally adjacent. Additionally, Rayleigh scattering images were acquired simultaneously with these PLIF images using a second Nd:YAG laser and an un-intensified camera. However, it would be possible to conduct these measurements with a single, sufficiently energetic Nd:YAG laser.

Raman spectrum of methane in nitrogen, carbon dioxide, hydrogen, ethane, and propane environments

Using binary CH4 - mixtures with varied concentrations of H2, N2, CO2, C2H6 and C3H8 and a fixed ambient pressure of 25bar, the influence of the environment on spectral characteristics (Raman shift, half-width, peak intensity) of Q-branches of the ν1, ν2, ν3, and 2ν4 methane Raman bands are investigated. It is found that depending on the environment these bands demonstrate different changes in their Raman shifts and half-widths. It is shown that the ratios of peak intensities I(ν2)/I(ν1), I(ν3)/I(ν1) and I(2ν4)/I(ν1) are very sensitive to the environment. The Raman shifts and half-widths of CH4 bands are assumed to depend on the absolute concentration of molecules in the analyzed medium. The data obtained would be useful in Raman diagnostics of natural gas.

An in-situ Raman study on pristane at high pressure and ambient temperature

The CH Raman spectroscopic band (2800–3000cm−1) of pristane was measured in a diamond anvil cell at 1.1–1532MPa and ambient temperature. Three models are used for the peak-fitting of this CH Raman band, and the linear correlations between pressure and corresponding peak positions are calculated as well. The results demonstrate that 1) the number of peaks that one chooses to fit the spectrum affects the results, which indicates that the application of the spectroscopic barometry with a function group of organic matters suffers significant limitations; and 2) the linear correlation between pressure and fitted peak positions from one-peak model is more superior than that from multiple-peak model, meanwhile the standard error of the latter is much higher than that of the former. It indicates that the Raman shift of CH band fitted with one-peak model, which could be treated as a spectroscopic barometry, is more realistic in mixture systems than the traditional strategy which uses the Raman characteristic shift of one function group.

Short Wave Upwelling Radiative Flux (SWupRF) within Near Infrared (NIR) Wavelength Bands of O2, H2O, CO2, and CH4 by Argus 1000 Along with GENSPECT Line by Line Radiative Transfer Model

ABSTRACTThis study develops an algorithm for short wave upwelling radiative flux (SWupRF) within near infrared wavelength band based on space orbiting Argus 1000 micro-spectrometer. Argus was hurled on aboard CanX-2 satellite on April 28, 2008 as part of a technology demonstration mission. It is operating within 900 nm to 1700 nm wavelength band with a spectral resolution of 6 nm and spatial resolution of 1.4 km. We calculate the SWupRF due to the absorption of O2, H2O, CO2, and CH4 within the selected wavelength band of each gas. A GENSPECT line by line radiative transfer model is applied to perform radiative transfer simulations to calculate the radiative flux by varying surface albedo and mixing ratios of the selected greenhouse gases. Finally, the SWupRFsyn estimated from GENSPECT was compared with SWupRFobs of Argus 1000 over a period of 4 years (2009 and 2013). The authors determined that the selected satellite data set of weeks 75 pass 43 and week 14 pass 52 showing minimum 0.850 (0.10 to 1.60) W/m2 and maximum 1.450 (0.600 to 2.30) W/m2 respectively. Further analysis will be required by applying the SWupRF model to find the radiative effects of smoky areas and clouds within the Argus wavelength range.

A fundamental study of octanohydroxamic acid adsorption on monazite surfaces

The adsorption mechanism of octanohydroxamic acid (OHA) on monazite was studied using kinetic, isotherm, and thermodynamic adsorption tests as well as FTIR, titration, and micro-flotation experiments. The adsorption mechanism was described as a chemisorption/surface precipitation process. At low OHA concentrations, adsorption occurred by chemisorption as a result of the reaction between surface active sites and OHA molecules. With an increase in concentration and interaction time, surface precipitation occurred. For chemisorption, adsorption was an exothermic and entropy driven process and maximum adsorption was achieved at pH9.0 due to more active sites. In an acidic environment, such as pH3.0, adsorption was achieved via chemisorption and hydrophobic bonding. However, a strong basic and higher temperature environment contributes to surface precipitation of basic rare earth hydroxamate. FTIR tests showed the movement of CH2 band position from 2924cm−1 to 2920cm−1 with increases in pH values from 3.0 to 6.0, 9.0, and 11.0, which corresponds to the status of chemisorbed and surface precipitated OHA, respectively.

Mid-wave infrared liquid crystal shutter for breathalyzer applications

There exists a problem with an in situ diagnostics of contamination of ethyl alcohol in a human being exhaled air. When ethyl alcohol in a mouth blowing (in a gaseous state) exists, the characteristic C H stretch absorption bands in CH 3 and CH 2 functional groups in ethanol (CH 3 CH 2 OH) appear at a wavelength of λ = 3.42 μm. To investigate the presence of ethyl alcohol in exhaled human air, the light beam of λ = 3.42 μm is passing through an air sample. If one alternately measures the intensity of the investigated beam and the reference, a percentage of ethanol in the air sample can be estimated using a sensitive nondispersive infrared (NDIR) system with a stable operating flow mass detector. To eliminate a mechanical chopper and noise generating stepper motors, a photonic chopper as a liquid crystal shutter for λ = 3.42 μm has been designed. For this purpose, an innovative infrared nematic liquid crystal mixture was intentionally prepared. The working mixture was obtained by a selective removal of C H bonds and its exchange by heavier polar substituents, what ensures a lack of absorption band of C H bonds. The paper presents theory, concept and final experimental results of the infrared nematic liquid crystals mixture and the liquid crystal shutter for breathalyzer applications.

Abundances of the light elements from UV (HST) and red (ESO) spectra in the very old star HD 84937

Aims. In order to provide a better basis for the study of mechanisms of nucleosynthesis of the light elements beyond hydrogen and helium in the oldest stars, the abundances of C, O, Mg, Si, P, S, K, and Ca have been derived from UV-HST and visible-ESO high resolution spectra in the old, very metal-poor star HD 84937, at a metallicity that is 1/200 that of the Sun’s. For this halo main-sequence turnoff star, the abundance determination of P and S are the first published determinations. Methods. The LTE profiles of the lines were computed and fitted to the observed spectra. Wherever possible, we compared the abundances derived from the UV spectrum to abundances derived from the visible or near-infrared spectra, and also corrected the derived abundances for non-LTE effects. Three-dimensional (3D) CO5BOLD model atmospheres have been used to determine the abundances of C and O from molecular CH and OH bands. Results. The abundances of these light elements relative to iron in HD 84937 are found to agree well with the abundances of these elements in classical metal-poor stars. Our HD 84937 carbon abundance determination points toward a solar (or mildly enhanced above solar) value of [C/Fe]. The modest overabundance of the α elements of even atomic number Z, typical of halo turnoff stars, is confirmed in this example. The odd-Z element P is found to be somewhat deficient in HD 84937, at [P/Fe] = −0.32, which is again consistent with the handful of existing determinations for turnoff stars of such low metallicity. We show that the abundance of oxygen, deduced from the OH band from 3D computations, is not compatible with the abundance deduced from the red oxygen triplet. This incompatibility is explained by the existence of a chromosphere heating the shallow layers of the atmosphere where the OH band, in 3D computations, is mainly formed. Conclusions. The abundance ratios are compared to the predictions of models of galactic nucleosynthesis and evolution.

Collisional line-shape parameters and their temperature dependence for the ν1+ν3 band of C2H2 perturbed by CO2

CO2-broadened line widths and CO2-pressure induced line shifts have been measured for 42 R- and P-branch transitions in the ν1+ν3 band of acetylene at seven temperatures in the range 216–333K to obtain the temperature dependences of broadening and shift coefficients. The spectra were recorded by a 3-channel tunable diode laser spectrometer, and the traditional Voigt-profile model was employed to retrieve the line parameters with a multispectrum fitting procedure. The line-broadening and line-shifting coefficients as well as their temperature-dependence parameters have been also evaluated theoretically, in the frame of a semi-empirical approach based on analytical Anderson-type expressions and including a few-parameter correction to account for the real curved trajectories. Being validated by comparison with measurements, this approach has been used to compute extensive (0≤J≤70) R- and P-line lists which could be useful for atmospheric/astrophysical applications and spectroscopic databases.

Using high-resolution laboratory and ground-based solar spectra to assess CH4 absorption coefficient calculations

A quadratic-speed-dependent Voigt line shape (qSDV) with line mixing (qSDV+LM), together with spectroscopic line parameters from Devi et al. [1,2] for the 2v3 band of CH4, was used to retrieve total columns of CH4 from atmospheric solar absorption spectra. The qSDV line shape (Tran et al., 2013) [3] with line mixing (Lévy et al., 1992) [4] was implemented into the forward model of GFIT (the retrieval algorithm that is at the heart of the GGG software (Wunch et al., 2015) [5]) to calculate CH4 absorption coefficients. High-resolution laboratory spectra of CH4 were used to assess absorption coefficients calculated using a Voigt line shape and spectroscopic parameters from the atm line list (Toon, 2014) [6]. The same laboratory spectra were used to test absorption coefficients calculated using the qSDV+LM line shape with spectroscopic line parameters from Devi et al. [1,2] for the 2v3 band of CH4 and a Voigt line shape for lines that don’t belong to the 2v3 band. The spectral line list for lines that don’t belong to the 2v3 band is an amalgamation of multiple spectral line lists. We found that for the P, Q, and R branches of the 2v3 band, the qSDV+LM simulated the laboratory spectra better than the Voigt line shape. The qSDV+LM was also used in the spectral fitting of high-resolution solar absorption spectra from four ground-based remote sensing sites and compared to spectra fitted with a Voigt line shape. The average root mean square (RMS) residual for 131,124 solar absorption spectra fitted with absorption coefficients calculated using the qSDV+LM for the 2v3 band of CH4 and the new spectral line list for lines for lines that don’t belong to the 2v3 band, was reduced in the P, Q, and R branches by 5%, 13%, and 3%, respectively when compared with spectra fitted using a Voigt line shape and the atm line list. We found that the average total column of CH4 retrieved from these 131,124 spectra, with the qSDV+LM was 1.1±0.3% higher than the retrievals performed using a Voigt and the atm line list. The airmass dependence of the retrieved total columns was found to change depending on the choice of spectral line shape. With the Voigt line shape, we found a minimum in CH4 total columns at a solar zenith angle (SZA) of about 70°. With the qSDV+LM, the retrieved total column of CH4 decreased monotonically as a function of SZA.

Green Synthesis of Iron Nanoparticles using Aqueous Extract of Musa ornata Flower Sheath against Pathogenic Bacteria

Iron nanoparticles were synthesized using Musa ornata flower sheath extract. The optimum precursor salt concentration, pH of the reaction mixture, ratio between reducing agent and precursor salt and time for the synthesis of iron nanoparticles were found to be 5 mM, 9.0, 3:7 and 0th h respectively. The synthesized iron nanoparticles were characterised by UV/Vis absorption spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, atomic force microscope and particle size analyser. UV/Vis absorption showed a characteristic absorption peak of iron oxide nanoparticles in the range of 250-350 nm. Fourier transform infrared spectroscopy measurement was carried out to identify the possible molecules like carbonyl, CH and OH band. From the X-ray diffraction method, it was found that the average particle size of magnetite nanoparticles was found to be 43.69 nm. The synthesized iron nanoparticles had antibacterial activity against pathogenic bacteria like Staphylococcus aureus, Streptococcus agalactiae, Escherichia coli and Salmonella enterica by well diffusion method. This biosynthesis approach has been found to be cost effective, eco-friendly and promising for applications in various fields.

Spatial investigation of plasma emission from laminar diffusion methanol, ethanol, and n-propanol alcohol flames using LIBS method

Laser-induced breakdown spectroscopy (LIBS) technique is used to record some plasma emissions of different laminar diffusion methanol, ethanol, and n-propanol alcohol flames, to investigate the shapes, structures (i.e., reactants and products zones), kind, and quality of burning in different areas. For this purpose, molecular bands of CH, CH*, C2, CN, and CO as well as atomic and ionic lines of C, H, N, and O are identified, simultaneously. Experimental results indicate that the CN and C2 emissions have highest intensity in LIBS spectrum of n-propanol flame and the lowest in methanol. In addition, lowest content of CO pollution and better quality of burning process in n-propanol fuel flame toward ethanol and methanol are confirmed by comparison between their CO molecular band intensities. Moreover, variation of the signal intensity from these three flames with that from a known area of burner plate is compared. Our findings in this research advance the prior results in time-integrated LIBS combustion application and suggesting that LIBS can be used successfully with the CCD detector as a non-gated analytical tool, given its simple instrumentation needs, real-time capability applications of molecular detection in laminar diffusion flame samples, requirements.

Comparative kinetic analysis of isothermal extraction of caffeine from guarana seed under conventional and microwave heating

The kinetics of the isothermal extraction of caffeine from the guarana seed powder with water under conventional (CH) and microwave heating (MWH) were investigated. By applying the isoconversional method, it was established that the kinetics of the caffeine extraction under CH and also under MWH is an elementary kinetic process. The model fitting method was used to determine the kinetics model of caffeine extraction. It was found that the kinetics of the caffeine extraction for both heating modes can be described by the Jander’s equation. The rate of the extraction of caffeine under MWH is ∼2 times higher than under CH. The values of kinetics parameters (Ea and lnA) of the extraction process under MWH are lower than for CH. The established influence of MWH on the kinetics of caffeine extraction is explained with a specific activation mechanism of water molecules and with an increase in the energy of the ground vibration level of resonant oscillator of N3–CH3 band of caffeine molecule (ν=317cm−1) which is caused by the absorption of microwave energy.

A 3D-psoriatic skin model for dermatological testing: The impact of culture conditions

BackgroundInadequate representation of the human tissue environment during a preclinical screen can result in inaccurate predictions of compound effects. Consequently, pharmaceutical investigators are searching for preclinical models that closely resemble original tissue for predicting clinical outcomes. MethodsThe current research aims to compare the impact of using serum-free medium instead of complete culture medium during the last step of psoriatic skin substitute reconstruction. Skin substitutes were produced according to the self-assembly approach. ResultsSerum-free conditions have no negative impact on the reconstruction of healthy or psoriatic skin substitutes presented in this study regarding their macroscopic or histological appearances. ATR-FTIR results showed no significant differences in the CH2 bands between psoriatic substitutes cultured with or without serum, thus suggesting that serum deprivation did not have a negative impact on the lipid organization of their stratum corneum. Serum deprivation could even lead to a better organization of healthy skin substitute lipids. Percutaneous analyses demonstrated that psoriatic substitutes cultured in serum-free conditions showed a higher permeability to hydrocortisone compared to controls, while no significant differences in benzoic acid and caffeine penetration profiles were observed. ConclusionsResults obtained with this 3D-psoriatic skin substitute demonstrate the potential and versatility of the model. It could offer good prediction of drug related toxicities at preclinical stages performed in order to avoid unexpected and costly findings in the clinic. General significanceTogether, these findings offer a new approach for one of the most important challenges of the 21st century, namely, prediction of drug toxicity.

Evidence for multiple populations in the intermediate-age cluster Lindsay 1 in the SMC

Abstract Lindsay 1 is an intermediate-age (≈8 Gyr) massive cluster in the Small Magellanic Cloud. Using VLT FORS2 spectra of 16 probable cluster members on the lower red giant branch of the cluster, we measure CN and CH band strengths (at ≃ 3883 and 4300 Å, respectively), along with carbon and nitrogen abundances and find that a sub-population of stars has significant nitrogen enrichment. A lack of spread in carbon abundances excludes evolutionary mixing as the source of this enrichment, so we conclude that this is evidence of multiple populations. Therefore, Lindsay 1 is the youngest cluster to show such variations, implying that the process triggering the onset of multiple populations must operate until at least redshift ∼1.

Efficacy of aqueous leaf extracts of negro coffee (<i>Cassia occidentalis</i>) and lemon grass (<i>Cymbopogon citratus</i>) in the management of nematode pests of okra (<i>Abelmoschus esculentus</i> l. Moench)

A two-year rain-fed field trials to evaluate the efficacy of aqueous leaf extracts of Cassia occidentalis and Cymbopogon citratus at different levels in the management of nematode pests of okra was conducted. The levels of treatments used were 25, 50, 75 and 100 %, where 0% served as control. The experimental design was a randomized complete block design (RCBD). Effects of treatments on growth, yield, soil nematode population, root weight and root gall indices were determined. Phytochemical screening and infra-red spectrum to determine the secondary metabolites in the leaf extracts were also carried out. It was observed that the treated plants especially those that received 50% level and above performed significantly better ( p =0.05) than the control with respect to the measured parameters. The phytochemical result revealed the presence of tannin (7.4%), crude alkaloids (2.5%), saponin (0%) and crude oxalates (42.28 mg/g) in cassia while lemon grass contained tannin (4.5%), crude alkaloids (0.52%,), saponin (1.76%) and oxalates (0%). The infra-red spectrum revealed that the two plant extracts contained very strong and broad absorption bands ~3400 -1 cm region, assignable to ~NH stretching mode probably of alkaloid family. The medium absorption bands were due to ~CH bands which are common in natural products. The medium absorption bands are also strong indicators of other compounds in the leaf extracts. The use of botanically derived crude leaf extracts of cassia at 50% and lemon grass at 75% in the management of nematode pests of okra will therefore be of economic benefit, ensuring food security. K ey w o r d s: Nematodes Phytochemical, screening Infra-red spectrum, Secondary metabolites

Observation of Evidence for the π*-σ* Hyperconjugation in the S1 State of o-, m-, and p-Fluorotoluenes by Double-Resonance Infrared Spectroscopy.

Drastic changes of the methyl internal rotation potential energy functions upon the electronic excitation have been reported for o- and m-fluorotolunes [ Okuyama , K. , Mikami , N. , and Ito , M. J. Phys. Chem. 1985 , 89 , 5617 - 5625 ], and their physical origin has been attributed to the π*-σ* hyperconjugation. To observe direct evidence of the π*-σ* hyperconjugation, double-resonance infrared spectroscopy was carried out in the CH stretching vibrational region in both the S0 and S1 states of jet-cooled o-, m-, and p-fluorotoluenes. In the spectra of both o- and m-fluorotoluenes, some of the methyl CH bands were red-shifted upon the electronic excitation while the residual CH bands stayed in the same frequency region. The normal-mode analysis demonstrated that the shift behavior correlates to the relative conformation between the methyl CH bond and the phenyl ring plane. This conformation-dependent methyl CH bond weakening clearly supports the presence of the π*-σ* hyperconjugation in o- and m-fluorotoluenes. The similar red-shift of the methyl CH bands upon the electronic excitation was seen also in p-fluorotoluene though the magnitude of the shift was much smaller. The mechanism of its internal rotation potential energy behavior, however, can be different from those of the o- and m-isomers.

On the Detection of Robust Multidecadal Changes in Earth’s Outgoing Longwave Radiation Spectrum

Abstract Differences between Earth’s global mean all-sky outgoing longwave radiation spectrum as observed in 1970 [Interferometric Infrared Spectrometer (IRIS)], 1997 [Interferometric Monitor for Greenhouse Gases (IMG)], and 2012 [Infrared Atmospheric Sounding Instrument (IASI)] are presented. These differences are evaluated to determine whether these are robust signals of multidecadal radiative forcing and hence whether there is the potential for evaluating feedback-type responses. IASI–IRIS differences range from +2 K in the atmospheric window (800–1000 cm−1) to −5.5 K in the 1304 cm−1 CH4 band center. Corresponding IASI–IMG differences are much smaller, at 0.2 and −0.8 K, respectively. More noticeably, IASI–IRIS differences show a distinct step change across the 1042 cm−1 O3 band that is not seen in IASI–IMG comparisons. This step change is a consequence of a difference in behavior when moving from colder to warmer scenes in the IRIS data compared to IASI and IMG. Matched simulations for the relevant periods using ERA reanalyses mimic the spectral behavior shown by IASI and IMG rather than by IRIS. These findings suggest that uncertainties in the spectral response of IRIS preclude the use of these data for quantitative assessments of forcing and feedback processes.

IHWG-ICL: Methane Sensing with Substrate-Integrated Hollow Waveguides Directly Coupled to Interband Cascade Lasers

The development of a compact iHWG-ICL gas sensor combining innovative substrate-integrated hollow waveguides (iHWG) with mid-infrared emitting type-II interband cascade lasers (ICL) is presented. Hence, tunable laser absorption spectroscopy (TLAS) with iHWGs in direct absorption mode is enabled. Using a room-temperature distributed feedback (DFB) ICL emitting at approximately 3.366 μm, quantitative sensing of methane was demonstrated. Wavelength scanning was obtained via current tuning for monitoring an isolated line in the v3 fundamental band of CH4. The obtained spectra were compared to calculated spectra derived from the HITRAN2012 database. Furthermore, the performance of iHWGs simultaneously serving as miniaturized gas cell and as efficient optical waveguide at various absorption path lengths was tested and optimized. Calibration functions in the concentration range of 50 to 400 ppmv were established enabling limits of detection ranging from 6 to 28 ppmv. Hence, the combination of iHWGs with ICLs fac...

High-speed flamefront imaging in premixed turbulent flames using planar laser-induced fluorescence of the CH C−X band

We describe efforts to develop kHz-rate or high-speed planar laser-induced fluorescence (PLIF) of the CH radical for application to premixed flames. The basic approach used here involves excitation and detection of the CH radial via the C2Σ+−X2Π (v′=0, v″=0) band, which has transitions in the wavelength range λ≈310–320nm. Transitions in this band are generally stronger than those in the A−X and B−X bands of CH and the radiative lifetimes are shorter too. Thus, the C−X band should have advantages with regard to CH detectability in atmospheric flames, and we show that good CH-PLIF signal-to-noise and signal-to-background ratios can be attained at a 10-kHz interrogation rate and that the spatial resolution (of the CH layer) is reasonably good as well. Of course, strong OH lines, from the A2Σ+−X2Π (0,0) and (1,1) bands, lie nearby the CH C−X lines. While this can create some interference in the detection of CH, we demonstrate that OH lines can be avoided, if desired, or excited, if desired. Indeed, easy access to either CH or OH is a substantial benefit of the method outlined herein. Furthermore, we show that simultaneous imaging of CH and OH—using a single laser system and camera—is possible too. We demonstrate the utility of this approach for resolving the flamefront dynamics with 10-kHz measurements in a turbulent, premixed methane–air Bunsen flame: we see intrusion of flame and products into the reactant-zone, which appears to accelerate the consumption of the reactant core, and fingers of flame and reactants that extend into the product-zone and then pinch off and burn out.