Wavenumber Range Research Articles

A self-adaptive model for sensing total phosphorus in natural water bodies using Fourier transform mid-infrared attenuated total reflectance spectroscopy

As the most economically developed area in China, the environmental water quality of Guangdong-Hong Kong-Macao Greater Bay Area has received extensive attention, and the spatial variations of total phosphorus (TP) in the Greater Bay were significant, conventional laboratory analysis is difficult to meet the requirements of TP monitoring due to time and cost consuming, and Fourier transform infrared attenuated total reflectance spectroscopy (FTIR-ATR) technology, combined with the self-adaptive partial least squares (SA-PLS) model, was used to determine the TP concentration. The results showed that P-O vibrations were observed in the wavenumber range of 1200–900 cm−1, and prediction models were established by using this range. For the conventional partial least squares (PLS) model, the R2, RMSE and RPD were 0.817, 0.022 mg L−1 and 2.335, respectively, while for the SA-PLS model the prediction was improved with the values of 0.965, 0.010 mg L−1, 5.296, respectively, and the SA-PLS mode prediction was satisfied when the TP content in water was more than 0.05 mg L−1. It was found that the TP determination was interfered by sulfate, when the sulfate content was < 100 mg L−1, both SA-PLS and the conventional PLS model could be used for quantitative analysis of TP; when sulfate content was > 100 mg L−1, PLS model could not be used while the SA-PLS model still achieved an excellent prediction. Therefore, FTIR-ATR combined with SA-PLS model can rapidly determine TP in water, providing an alternative strategy for monitoring TP in natural water bodies.

Variation Analysis of Starch Properties in Tartary Buckwheat and Construction of Near-Infrared Models for Rapid Non-Destructive Detection.

Due to the requirements for quality testing and breeding Tartary buckwheat (Fagopyrum tartaricum Gaerth), it is necessary to find a method for the rapid detection of starch content in Tartary buckwheat. To obtain samples with a continuously distributed chemical value, stable Tartary buckwheat recombinant inbred lines were used. After scanning the near-infrared spectra of whole grains, we employed conventional methods to analyze the contents of Tartary buckwheat. The results showed that the contents of total starch, amylose, amylopectin, and resistant starch were 532.1-741.5 mg/g, 176.8-280.2 mg/g, 318.8-497.0 mg/g, and 45.1-105.2 mg/g, respectively. The prediction model for the different starch contents in Tartary buckwheat was established using near-infrared spectroscopy (NIRS) in combination with chemometrics. The Kennard-Stone algorithm was used to split the training set and the test set. Six different methods were used to preprocess the spectra in the wavenumber range of 4000-12,000 cm-1. The Competitive Adaptive Reweighted Sampling algorithm was then used to extract the characteristic spectra, and the prediction model was built using the partial least squares method. Through a comprehensive analysis of each parameter of the model, the best model for the prediction of each nutrient was determined. The correlation coefficient of calibration (Rc) and the correlation coefficient of prediction (Rp) of the best models for total starch and amylose were greater than 0.95, and the Rc and Rp of the best models for amylopectin and resistant starch were also greater than 0.93. The results showed that the NIRS-based prediction model fulfilled the requirement for the rapid determination of Tartary buckwheat starch, thus providing an effective technical approach for the rapid and non-destructive testing of starch content in the food science and agricultural industry.

Facile synthesis of ZnO nanoparticles using Nigella Sativa extract and its role as catalyst in production of bio-oil and degradation of methylene blue dye

Zinc Oxide (ZnO) nanoparticles (NPs) were synthesized using an environmentally benign biogenic approach employing an extract of kernels of Nigella Sativa (kalonji). The presence of primary and secondary metabolites in Nigella Sativa extract acted as the capping and reducing agent. The as-synthesized ZnO NPs were characterized using various advanced techniques i.e., UV, SEM, XRD, EDS, TGA, DSC, and FTIR spectra. UV characterization of ZnO NPs revealed a peak within the 350-400 cm−1 range, confirming their successful formation. XRD spectra revealed that the particles possess a nano-rods and platelets structure, with an average size of 65 nm. XRD analysis revealed that the particles possess a size of 65 nm with a nano-rods and platelets structure. FTIR spectra of the ZnO NPs exhibited a peak at a wavenumber range of 500–600 cm−1. The newly fabricated ZnO NPs were utilized in a pyrolysis reaction for the production of high-yield bio-oil, resulting in a maximum yield of 65.6 % at 350 °C. The spectra of the bio-oil display distinct peaks at 1340 cm−1, 2923.6 cm−1, and 1617 cm−1, which suggest the existence of phenolic and carbonyl chemicals. After incubating for 24 h under UV light, they also demonstrated significant catalytic degradation of methylene blue dye. The highest degradation was recorded to be an average of 71 % in 60 min of UV exposure. Taken together, ZnO NPs developed by eco-benign methods have the potential to be implemented as a novel catalytic system in the production of bio-oil as well as the remediation of dye-harboring industrial wastewater.

Dynamics of discrete solitons in the fractional discrete nonlinear Schrödinger equationwith the quasi-Riesz derivative.

We elaborate a fractional discrete nonlinear Schrödinger (FDNLS) equationbased on an appropriately modified definition of the Riesz fractional derivative, which is characterized by its Lévy index (LI). This FDNLS equationrepresents a novel discrete system, in which the nearest-neighbor coupling is combined with long-range interactions, that decay as the inverse square of the separation between lattice sites. The system may be realized as an array of parallel quasi-one-dimensional Bose-Einstein condensates composed of atoms or small molecules carrying, respectively, a permanent magnetic or electric dipole moment. The dispersion relation (DR) for lattice waves and the corresponding propagation band in the system's linear spectrum are found in an exact form for all values of LI. The DR is consistent with the continuum limit, differing in the range of wave numbers. Formation of single-site and two-site discrete solitons is explored, starting from the anticontinuum limit and continuing the analysis in the numerical form up to the existence boundary of the discrete solitons. Stability of the solitons is identified in terms of eigenvalues for small perturbations, and verified in direct simulations. Mobility of the discrete solitons is considered too, by means of an estimate of the system's Peierls-Nabarro potential barrier, and with the help of direct simulations. Collisions between persistently moving discrete solitons are also studied.

Raman microscopy allows to follow internalization, subcellular accumulation and fate of iron oxide nanoparticles in cells

An important issue in the context of both potenial toxicity of iron oxide nanoparticles (IONP) and their medical applications is tracking of the internalization process of these nanomaterials into living cells, as well as their localization and fate within them. The typical methods used for this purpose are transmission electron microscopy, confocal fluorescence microscopy as well as light-scattering techniques including dark-field microscopy and flow cytometry. All the techniques mentioned have their advantages and disadvantages. Among the problems it is necessary to mention complicated sample preparation, difficult interpretation of experimental data requiring qualified and experienced personnel, different behavior of fluorescently labeled IONP comparing to those label-free or finally the lack of possibility of chemical composition characteristics of nanomaterials.The purpose of the present investigation was the assessment of the usefulness of Raman microscopy for the tracking of the internalization of IONP into cells, as well as the optimization of this process. Moreover, the study focused on identification of the potential differences in the cellular fate of superparamagnetic nanoparticles having magnetite and maghemite core.The Raman spectra of U87MG cells which internalized IONP presented additional bands which position depended on the used laser wavelength. They occurred at the wavenumber range 1700–2400 cm−1 for laser 488 nm and below the wavenumber of 800 cm−1 in case of laser 532 nm. The intensity of the mentioned Raman bands was higher for the green laser (532 nm) and their position, was independent and not characteristic on the primary core material of IONP (magnetite, maghemite).The obtained results showed that Raman microscopy is an excellent, non-destructive and objective technique that allows monitoring the process of internalization of IONP into cells and visualizing such nanoparticles and/or their metabolism products within them at low exposure levels. What is more, the process of tracking IONP using the technique may be further improved by using appropriate wavelength and power of the laser source.

Authentication of Mentha arvensis essential oil using attenuated total reflectance-Fourier transform infrared spectrophotometry coupled with chemometrics

Mentha arvensis essential oil is considered a product of high economic value that finds application in the food, pharmaceutical, and cosmetic industries. They are subjected to adulteration with synthetic chemicals and low-cost vegetable oils with higher boiling points. A rapid, non-destructive method using infrared spectroscopy has been investigated to authenticate Mentha arvensis Essential oils, helping to maintain their quality and trustworthiness for users who rely on them for their beneficial properties. Authentic samples of Mentha arvensis essential oil were obtained and analyzed using Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy in the wavenumber range of 500–4000 cm−1. The resulting spectra were pre-processed with Multiplicative Scatter Correction. The initial investigation involved exploratory analysis using Principal Component Analysis, followed by discriminant analysis using Principal Component Analysis-Linear Discriminant Analysis, Partial Least Squares-Discriminant Analysis, and Soft Independent Modelling for Class Analogy. The classification models developed have a high accuracy of 100 % thus demonstrating higher efficiency in distinguishing different adulterants in Mentha arvensis essential oil with both high specificity and sensitivity. To assess the extent of adulteration in Mentha arvensis essential oil, Partial Least Squares Regression and Principal Component Regression were employed. The regression models were capable of identifying adulteration levels as low as 5 % in the essential oil thus enabling FTIR spectroscopy coupled with chemometrics to serve as a non-destructive method for identifying commonly used adulterants, potentially replacing traditionally used Chromatographic and Thermo-Gravimetric Analysis methods.

Background-free mid-infrared absorption spectroscopy using sub-cycle pulses

We have demonstrated highly sensitive single-shot based background-free mid-infrared (MIR) absorption spectroscopy using sub-cycle MIR pulses generated through filamentation. The MIR pulse transmitted through a sample was upconverted with a fast rising and long tailing gate pulse through four-wave difference frequency generation in a silicon membrane. By recording the upconverted spectrum of the free induction decay alone, we successfully measured the absorption spectrum as a positive signal in the wavenumber range from 500 to 4500 cm−1, which covers both the fingerprint and functional group regions. We obtained an absorption spectrum of ∼50 mM of aqueous glucose, which is not detectable with a standard Fourier transform infrared spectrometer.

MARVEL analysis of high-resolution rovibrational spectra of 16O12C18O.

Empirical rovibrational energy levels are presented for the third most abundant, asymmetric carbon dioxide isotopologue, 16O12C18O, based on a compiled dataset of experimental rovibrational transitions collected from the literature. The 52 literature sources utilized provide 19,438 measured lines with unique assignments in the wavenumber range of 2-12,676 cm-1. The MARVEL (Measured Active Rotational-Vibrational Energy Levels) protocol, which is built upon the theory of spectroscopic networks, validates the great majority of these transitions and outputs 8786 empirical rovibrational energy levels with an uncertainty estimation based on the experimental uncertainties of the transitions. Issues found in the literature data, such as misassignment of quantum numbers, typographical errors, and misidentifications, are fixed before including them in the final MARVEL dataset and analysis. Comparison of the empirical energy-level data of this study with those in the line lists CDSD-2019 and Ames-2021 shows good overall agreement, significantly better for CDSD-2019; some issues raised by these comparisons are discussed.

High-Temperature Line List of Phosphaethyne (HCP).

Phosphaethyne (HCP) has been detected in circumstellar envelopes; its spectroscopic line list is helpful for modeling the relevant atmospheric opacity. We present the first comprehensive line list for HCP(X1Σ+) using robust first-principles methods. The analytical potential energy surface and dipole moment surface were constructed based on 26478 ab initio points from coupled-cluster calculations, along with the considerations of core-valence electron correlation and scalar relativistic effects. The variational nuclear motion program TROVE was used to obtain the ro-vibrational energy levels, Einstein A coefficients, and so on. The J-dependent Coriolis-decoupled Hamiltonian was adopted in the variational calculations with k ≤ 20, and the linear molecule treatment was applied to consider the l-type doubling of the bending vibration. The line list contains almost 0.45 billion transitions between 1.21 million levels with rotational excitation up to J = 200. It covers the wavenumber range of 0-9000 cm-1 (wavelengths above 1.11 μm) and is suitable for temperatures up to 3000 K. The millimeter wave spectra agree well with the experiments, and the Fermi resonance between 2v2 and v3 bands has been reproduced.

Coherent structures formed by small particles in traveling-wave flows.

We experimentally verify the "phase locking model," which describes the formation of one-dimensional coherent structures by low-Stokes-number particles as proposed by Pushkin etal. [Phys. Rev. Lett. 106, 234501 (2011)0031-900710.1103/PhysRevLett.106.234501] in thermocapillary liquid bridges: When the particles form the coherent structures in time-periodic flows, the synchronous coupling of the toroidal vortex and the azimuthally traveling wave is achieved for a range of azimuthal wave number m. We further propose coherent structures of rational wave numbers in the azimuthal direction and unveil those experimentally.

Raman characterization of layer of graphene-like structures in 3d-transition metal-loaded charcoal by comparison with X-ray diffraction data

To evaluate the formation and changes in graphitic structures in transition-metal loaded charcoal, charcoal samples synthesized from Japanese cedar wood impregnated with 3d-transition metal (Cr, Mn, Fe, Co, Ni, Cu, Zn) ions were analyzed using microscopic Raman spectroscopy and powder X-ray diffractometry. The metal-loaded charcoal samples were carbonized at 650, 700, 750, 800, and 850 °C in downstream N2 gas. The Raman Gˊ-band, which shows the structural ordering of carbon atoms, was observed in the Raman spectra of Fe-, Co-, and Ni-loaded charcoal. The Gˊ-bands occurred at ≤ 2670 cm− 1 and shifted to 2700–2690 cm− 1 with increasing carbonization temperature. The Gˊ-band observed in the higher wavenumbers (2700–2690 cm− 1) range corresponded to an X-ray diffraction (XRD) peak at ∼ 26.3 ° assigned to the (002) plane of graphite-like structures. The high-wavenumber Gˊ-band also corresponded to the XRD detection of the carbide of the three metals. However, the XRD peak was not found for Co- and Ni-loaded charcoal samples exhibiting Gˊ-bands at ≤ 2670 cm− 1.

An implementation of nDGP gravity in Pinocchio

In this paper we investigate dark matter structure formation in the normal branch of the Dvali-Gabadadze-Porrati (nDGP) model using the PINOCCHIO algorithm. We first present 2nd order Lagrangian perturbation theory for the nDGP model, which shows that the 1st- and 2nd-order growth functions in nDGP are larger than those in ΛCDM. We then examine the dynamics of ellipsoidal collapse in nDGP, which is accelerated compared to ΛCDM due to enhanced gravitational interactions. Running the nDGP-PINOCCHIO code with a box size of 512 Mpc h -1 and 10243 particles, we analyze the statistical properties of the output halo catalogs, including the halo power spectrum and halo mass function. The calibrated PINOCCHIO halo power spectrum agrees with N-body simulations within 5% in the comoving wavenumber range k<0.3 (h Mpc-1) at redshift z=0. The agreement is extended to smaller scales for higher redshifts. For the cumulative halo mass function, the agreement between N-body and PINOCCHIO is also within the simulation scatter.

Breakdown mechanisms induced by stationary crossflow vortices in hypersonic three-dimensional boundary layers

This study investigates the crossflow breakdown of a Mach 6 flow over a swept flat plate by direct numerical simulation (DNS) considering three cases with different spanwise wavenumbers of stationary vortices. Transition in these cases is initiated by the linear and nonlinear evolution of these vortices, followed by secondary instabilities and breakdown due to type-I, type-II modes, and wall blowing/suction perturbations, respectively. The results showed that amplified secondary instabilities significantly distort the mean flow, causing a steep rise in the wall friction coefficient. Fourier analysis shows that, in this fast-varying flow region, the low-frequency disturbances undergo significantly greater amplifications than high-frequency disturbances. Moreover, the stability characteristics of the time- and spanwise-averaged mean flow were examined to elucidate the breakdown mechanisms. It was found that the unstable region initially contracts to a lower frequency band and then expands significantly in the spanwise wavenumber range at low frequencies. This suggests the significant amplifications of low-frequency disturbances, consistent with the observations from DNS. These amplified low-frequency disturbances, in turn, modify the mean flow, leading to the final breakdown. The presented mechanisms, highlighting the critical role of low-frequency disturbances in the breakdown process, are likely to be universally relevant across various parameter regimes.

DETECTION OF WHITE RICE ADULTERANTS IN LAMPUNG ROBUSTA COFFEE EXTRACT USING FT-IR METHOD BY FINGERPRINT ANALYSIS AND PRINCIPAL COMPONENT ANALYSIS

Lampung Province has 3 areas that produce coffee: West Lampung, Tanggamus, and Waykanan, which can produce 51,484 tons of coffee annually. The high demand for coffee and limited harvest are some factors that cause the addition of adulterants to coffee products such as corn, soybeans, rye, coffee beans, and rice. This study aims to detect rice adulterants in Lampung robusta coffee using the FTIR spectrophotometric method combined with chemometric analysis using the PCA (Principal Component Analysis) method. FTIR spectrophotometric method combined with chemometric analysis using PCA (Principal Component Analysis) method. The PCA method was validated using the cross-validation method. Samples were taken from 3 Lampung coffees on the market. The extraction process was carried out on Lampung coffee and Lampung rice from 3 regions using 96% ethanol. After concentrating, the coffee and rice extracts were measured using FTIR and read in the 4000-650 cm-1 wave number range. Different wave number curves were obtained between coffee and rice. A pre-processing chemometric analysis was performed, which resulted in the classification of Robusta coffee and rice using PC1 and PC2 (50% and 24%). The results of PCA analysis showed that PC1 and PC2 in the three Lampung coffee samples, samples A and C, did not contain adulterants, while sample B was suspected of containing white rice. Keywords: Alduteran, FTIR, Chemometrics, PCA, Lampung Robusta Coffee.

Parameters of a robotic loading device for selection seeder

In cassette-type selection seeders, a cassette loading device sequentially conveys cassettes filled with seed material to the planting mechanism of the seeder. (Research purpose) The research aims to calculate the geometric parameters and identify the cassette material in the development of a robotic cassette loading device for the selection seeder. (Materials and methods) The geometric parameters of the cassettes are determined based on the existing cassette loading device of the model SSS-2-6 selection seeder and the selection sowing specifi cations. Fourier transform infrared spectroscopy with the wavenumber range of 400-4000 cm–1 is used to identify a polymer material suitable for manufacturing cassettes and a guide plate for a selection seeder. (Results and discussion) The geometric parameters of cassettes, cells, cassette blocks, and guide plates are determined by using various design solutions employed in previous cassettes for the loading device. The objectives of the study also encompass the selection of polymer material for the manufacture of the cassette using 3D modeling techniques. To accomplish this, it was necessary to identify the specific polymer material of the plastic cassette and guide plate samples currently used in the loading device of the SSSe-6 selection seeder. The qualitative composition of these samples is determined by infrared spectroscopy using a Simex FT-801 Infrared Fourier spectrometer. (Conclusions) The geometric parameters essential for modeling, manufacturing and further development of a robotic cassette loading device are calculated. It has been established that the device is made of a copolymer consisting of acrylonitrile, polybutadiene and styrene (known as ABS plastic), which has a sliding friction coefficient approximately 0.47-0.54. In order to decrease the coefficient of cassette friction when driving along the guide plates, additives like ceramide can be introduced into ABS during their production enhancing its sliding properties.

Evaluation of subgrid-scale models in decaying rotating stratified turbulence

The results of large eddy simulation (LES) using four sub-grid scale (SGS) models, namely: constant coefficient Smagorinsky (CS), dynamic Smagorinsky (DS), a dynamic Clark (DC) model, and dynamic Lund-Novikov II-term model (DLN2M) for rotating stratified turbulence in the absence of forcing using large-scale isotropic initial conditions, are reported here. Three cases with varying ratios of Brunt-Väisälä frequency to the inertial wave frequency, N / f , have been chosen to evaluate the performance of SGS models. The Reynolds number and N / f are chosen as (a) Case 1: Re=3704, N / f = 5 , (b) Case 2: Re=6667, N / f = 40 and (c) Case 3: Re=6667, N / f = 138 . Various quantities including turbulent kinetic energy (tke), turbulent potential energy (tpe), total dissipation, potential and total energy spectra, and their fluxes, are analyzed. It is observed that the increase in the value of N / f leads to increased oscillations in the evolution of kinetic and potential energy. Our results suggest that the inclusion of the rotation rate tensor in SGS modeling leads to overall improvements in energy evolution predictions. The CS model produces the largest errors, while the DS and the DC models are more comparable to each other. Spectral analysis of total energy and their fluxes shows that the CS, DS and DC models can reasonably predict the large-scale motion ( κ < 10 ), while the DLN2M model improves the energy prediction in the wavenumber range ( 10 < κ < 64 ) in comparison to other SGS models.

Unlocking the potential of multicomponent mesoporous bioactive glass nanoparticles: An approach to enhanced ion therapy

This work presents the synthesis and characterization of a multicomponent mesoporous bioactive glass (MMBG) derived from the composition of 58S glass modified with copper, zinc, and boron. Morphological data revealed the presence of spherical particles with an average size of 616 nm and a specific surface area of 295 m2·g−1. X-ray diffractogram analysis confirmed the lack of long-range order in the MMBG, indicating the presence of a disordered vitreous structure characteristic of glass. The structural scenario of the bioactive glass MMBG reveals a characteristic configuration of borosilicate glasses, where the [BO4] polyhedra, along with SiO4 tetrahedra, constitute the backbone of the glassy matrix. Concerning zinc and copper ions, they function similarly to calcium in compensating for the remaining negative charges within the borosilicate network, behaving as typical network-modifying ions. The presence of these heavy ions, coupled with the formation of the borosilicate network in MMBG, led to a 20 % increase in density compared to 58S glass. Additionally, alterations in the chemical composition and structure of MMBG resulted in a reduction in molar volume compared to 58S, indicating a decrease in the volume occupied by one mole of oxygen in the glass matrix, thereby increasing the oxygen packing density. The pH studies reveal that changes in the chemical composition of MMBG did not compromise its chemical reactivity in aqueous environments. The capability of MMBG glass to act as a bioactive agent for ion therapy is evidenced by its ability to deliver Zn and Cu ions, as substantiated by the gradual disappearance of absorption in wavenumber range of 690–470 cm−1, attributed to the vibration of Zn-O and Cu-O bonds. Preliminary in vitro assay for bioactivity in SBF revealed that the formation of apatite layer on the surface of MMBG glass was notably thicker and denser compared to 58S glass. This result highlights the superior bioactive response of the MMBG bioactive glass, indicating its potential as an exceptionally favorable material for various biomedical applications.

High resolution optimized high-order schemes for discretization of non-linear straight and mixed second derivative terms

In this paper, we propose a new set of midpoint-based high-order discretization schemes for computing straight and mixed nonlinear second derivative terms that appear in the compressible Navier-Stokes equations. Firstly, we detail a set of conventional fourth and sixth-order baseline schemes that utilize central midpoint derivatives for the calculation of second derivatives terms. To enhance the spectral properties of the baseline schemes, an optimization procedure is proposed that adjusts the order and truncation error of the midpoint derivative approximation while still constraining the same overall stencil width and scheme order. A new filter penalty term is introduced into the midpoint derivative calculation to help achieve high wavenumber accuracy and high-frequency damping in the mixed derivative discretization. Fourier analysis performed on the both straight and mixed second derivative terms show high spectral efficiency and minimal numerical viscosity with no odd-even decoupling effect. Numerical validation of the resulting optimized schemes is performed through various benchmark test cases assessing their theoretical order of accuracy and solution resolution. The results highlight that the present optimized schemes efficiently utilize the inherent viscosity of the governing equations to achieve improved simulation stability - a feature attributed to their superior spectral resolution in the high wavenumber range. The method is also tested and applied to non-uniform structured meshes in curvilinear coordinates, employing a supersonic impinging jet test case.

Unsteady Aerodynamic Forcing Due to Distortion in a Boundary Layer Ingesting Fan

Abstract Boundary Layer Ingestion (BLI) is a concept with the potential to reduce energy consumption needed for aircraft propulsion. For the fan this results in a need to work well in an environment of increased continuous distortion. The objective of this study is to increase the understanding of unsteady aerodynamic forces due to total pressure distortion in a BLI fan. This is done by using computational fluid dynamics to analyze a fan design intended for a BLI installation. Results include low subsonic to transonic operating speeds and distortion in a wide range of wave numbers. The forcing exhibits a significant dependency on the aeroacoustic cut-on/cut-off condition. This is in particular true at part speed where the normalized unsteady force rises sharply before dropping suddenly as the corrected speed or engine order increases. Unsteady pressure in the blade passage is observed to exhibit the same increase in level followed by a sudden drop once the cut-on limit is passed and undamped pressure waves propagating out from the blade row appear. The unsteady forces on the first three modes exhibit different sensitivities to the distortion wavelength but all are affected by the acoustic condition. By comparing results for the reference fan to a similar fan design with a higher blade count the cascade properties of the blade row are found to dominate the interaction. A result of this is that a higher blade count fan may be less affected by the distortion, and be less prone to propagate noise due to low engine order distortion.

Classification of healthy and cancerous colon cells by Fourier transform infrared spectroscopy

Colorectal cancer is one of the most diagnosed types of cancer in developed countries. Current diagnostic methods are partly dependent on pathologist experience and laboratories instrumentation. In this study, we used Fourier Transform Infrared (FTIR) spectroscopy in transflection mode, combined with Principal Components Analysis followed by Linear Discriminant Analysis (PCA-LDA) and Partial Least Squares – Discriminant Analysis (PLS-DA), to build a classification algorithm to diagnose colon cancer in cell samples, based on absorption spectra measured in two spectral ranges of the mid-infrared spectrum. In particular, PCA technique highlights small biochemical differences between healthy and cancerous cells: these are related to the larger lipid content in the former compared with the latter and to the larger relative amount of protein and nucleic acid components in the cancerous cells compared with the healthy ones. Comparison of the classification accuracy of PCA-LDA and PLS-DA methods applied to FTIR spectra measured in the 1000–1800 cm−1 (low wavenumber range, LWR) and 2700–3700 cm−1 (high wavenumber range, HWR) remarks that both algorithms are able to classify hidden class FTIR spectra with excellent accuracy (100 %) in both spectral regions. This is a hopeful result for clinical translation of infrared spectroscopy: in fact, it makes reliable the predictions obtained using FTIR measurements carried out only in the HWR, in which the glass slides used in clinical laboratories are transparent to IR radiation.