IR Microscopy Research Articles

Diffusion of chromium in zinc chalcogenides during hot isostatic pressing

The diffusion of chromium impurities in zinc chalcogenides (ZnS, ZnSe) during hot isostatic pressing (HIP) in the temperature range T = 1000–1330 °C and pressures P = 100–190 MPa has been investigated. The chromium concentration and its distribution over the sample volume with a step from 5 to 50 μm was determined by FTIR spectroscopy in combination with an IR microscope. The diffusion coefficients of Cr in ZnS and ZnSe at various temperatures and pressures were determined. The diffusion coefficients of Cr at 1300 °C were (7.0 ± 0.3) × 10−8 cm2/s in ZnSe and (3.4 ± 0.4) × 10−8 cm2/s in ZnS. It is shown that the temperature dependences are described by the Arrhenius equation, and the isostatic pressure does not affect the value of the diffusion coefficients.

Mineral Physicochemistry Underlying Feature-Based Extraction of Mineral Abundance and Composition from Shortwave, Mid and Thermal Infrared Reflectance Spectra

Reflectance spectroscopy allows cost-effective and rapid mineral characterisation, addressing mineral exploration and mining challenges. Shortwave (SWIR), mid (MIR) and thermal (TIR) infrared reflectance spectra are collected in a wide range of environments and scales, with instrumentation ranging from spaceborne, airborne, field and drill core sensors to IR microscopy. However, interpretation of reflectance spectra is, due to the abundance of potential vibrational modes in mineral assemblages, non-trivial and requires a thorough understanding of the potential factors contributing to the reflectance spectra. In order to close the gap between understanding mineral-diagnostic absorption features and efficient interpretation of reflectance spectra, an up-to-date overview of major vibrational modes of rock-forming minerals in the SWIR, MIR and TIR is provided. A series of scripts are proposed that allow the extraction of the relative intensity or wavelength position of single absorption and other mineral-diagnostic features. Binary discrimination diagrams can assist in rapidly evaluating mineral assemblages, and relative abundance and chemical composition of key vector minerals, in hydrothermal ore deposits. The aim of this contribution is to make geologically relevant information more easily extractable from reflectance spectra, enabling the mineral resources and geoscience communities to realise the full potential of hyperspectral sensing technologies.

Silica-Supported PdGa Nanoparticles: Metal Synergy for Highly Active and Selective CO2-to-CH3OH Hydrogenation.

The direct conversion of CO2 to CH3OH represents an appealing strategy for the mitigation of anthropogenic CO2 emissions. Here, we report that small, narrowly distributed alloyed PdGa nanoparticles, prepared via surface organometallic chemistry from silica-supported GaIII isolated sites, selectively catalyze the hydrogenation of CO2 to CH3OH. At 230 °C and 25 bar, high activity (22.3 molMeOH molPd–1 h–1) and selectivity for CH3OH/DME (81%) are observed, while the corresponding silica-supported Pd nanoparticles show low activity and selectivity. X-ray absorption spectroscopy (XAS), IR, NMR, and scanning transmission electron microscopy–energy-dispersive X-ray provide evidence for alloying in the as-synthesized material. In situ XAS reveals that there is a dynamic dealloying/realloying process, through Ga redox, while operando diffuse reflectance infrared Fourier transform spectroscopy demonstrates that, while both methoxy and formate species are observed in reaction conditions, the relative concentrations are inversely proportional, as the chemical potential of the gas phase is modulated. High CH3OH selectivities, across a broad range of conversions, are observed, showing that CO formation is suppressed for this catalyst, in contrast to reported Pd catalysts.

Advanced Formulation Design for Topical Creams Assisted with Vibrational Spectroscopic Imaging.

Vibrational spectroscopic imaging has become useful analytical tools for quality control of drug products. In this study, we applied microscopic attenuated total reflection (ATR)-IR and confocal Raman microscopy to elucidate microscopic structure of creams and for the formulation design in the development of semi-solid drug products. The model creams were prepared with prednisolone (PRD) and fluconazole (FLC) as active pharmaceutical ingredients and oily solvents such as mineral oil (MO), isopropyl myristate (IPM), benzyl alcohol (BA) and diethyl sebacate (DES). As a result of microscopic ATR-IR imaging, several domains indicating oily internal phase were observed, which had absorption around 1732 and 1734 cm-1 derived from MO, IPM and DES. In addition, domains of BA around 1009 cm-1 were observed at the complemental or similar position in the formulation with MO or DES, respectively. These results suggested that the creams were oil-in-water type and the distribution of domains would reflect the compatibility of the solvents. The contents of PRD and BA were determined quantitatively in each layer after the intentional separation of the creams and the results agreed well with the imaging analysis. Whereas, confocal Raman imaging allowed to visualize the distribution of the components in depth direction as well as two-dimensional plane. In particular, the Raman imaging would ensure the coexistence of FLC and BA as oily phase in the cream. From these results, the feasibility of spectroscopic imaging techniques was successfully demonstrated for the formulation design of semi-solid dosage forms.

Image fusion of IR and optical microscopy for mapping of biomolecules in tissue.

It is shown that a pixel-level image fusion technique can produce images that combine the spatial resolution of optical microscopy images of haematoxylin and eosin (H&E) stained tissue with the chemical information in Fourier transform infrared (FTIR) images. The fused images show minimal distortion and the higher spatial resolution of the H&E images overcomes the diffraction limit on the spatial resolution of the FTIR images. A consideration of the FTIR spectra of nucleic acids and collagen can explain the changes in contrast between non-cancerous oral epithelium and underlying stroma within fused images formed by combining an H&E stain of oral tissue with FTIR images of the tissue obtained at a number of wavenumbers.

Phase equilibria in Cd0.80Mn0.20Te solid solutions

The thermal properties of Cd0.80Mn0.20Te solid solutions were investigated in this article. Two methods of heat treatment were used for thermography of alloys, which allowed investigating their thermal properties. One of the methods of thermography of samples was to heat them to the maximum temperature at which they were kept for a certain time, followed by cooling of the sample. The data obtained by this type of thermography allow obtaining graphs which characterized the crystallization parameters of the melt Cd0.80Mn0.20Te. It is shown that the crystallization of the Cd0.80Mn0.20Te melt occurs without supercooling at its overheating less than 14 °С in comparison with the beginning of melting temperature, which indicates the two-phase melt. It is also shown that the crystallization rate of the Cd0.80Mn0.20Te melt increases with decreasing crystallization temperature. Thermography of alloys by the second method of heat treatment is to conduct a series of isothermal holding during heating of the samples to the maximum temperature (1150 °C). Thus, the parameters of alloy melting were investigated. It was determined that the volume fraction of solid phase in the Cd0.80Mn0.20Te melt decreases from 100% to 0% in the temperature range 1078-1095 °С. Based on the obtained data of differential thermal analyses the Cd0.80Mn0.20Te ingot was grown under controlled conditions. After cutting this crystal we can see several monocrystalline areas of different sizes. IR microscope showed that the minimum number of inclusions <7 mm in diameter distributed in different parts of the sample The value of the band gap in all samples ranges from 1.78 to 1.80 eV. The value of the resistivity of the crystal Cd0.80Mn0.20Te is 2•107 Ohm • cm at the beginning of the ingot and decreases by 2 orders of magnitude by the end of the ingot.

Application of microimaging to diffusion studies in nanoporous materials

Microimaging on the basis of, respectively, interference microscopy and IR microscopy permit the observation of the distribution of guest molecules in nanoporous solids and their variation with time. Thus attainable knowledge of both concentration gradients and diffusion fluxes provides direct access to the underlying diffusion phenomena. This includes, in particular, the measurement of transport diffusion under transient, i. e. under non-equilibrium conditions, and of self- or tracer diffusion on considering the rate of tracer exchange. Correlating the difference in guest concentration close to the external surface to its equilibrium value with the influx into the nanoporous solid, microimaging does as well allow the direct determination of surface resistances. Examples illustrating the variety of information thus attainable include the comparison of mass transfer under equilibrium and non-equilibrium conditions, single- and multicomponent diffusion and chemical reactions. They, finally, introduce into the potentials of microimaging for an in-depth study of mass transfer in mixed-matrix membranes. This tutorial review may serve as first introduction into the topic. Further references are linked for the interested reader.

Comparative antibacterial potential of silver nanoparticles prepared via chemical and biological synthesis

New and improved approaches are urgently needed to fight the increasing number of multi-drug resistant bacteria. The antibacterial effect of silver nanoparticles (AgNPs) prepared by standardized chemical and biological syntheses is compered here. Biological systems included extracts of Opuntia ficus-indica mucilage and extracellular growth broth of Aspergillus niger and Bacillus megaterium. The nanoparticles were characterized by infrared spectroscopy, IR, and transmission electron microscopy. All of the AgNPs shared characteristic IR peaks and had an average size of 20–60 nm. The AgNPs were mainly spherical regardless of synthetic path. The synthesis based on the extracellular broth of the fungus, due to the highest biomass and active compounds concentration, resulted in a high yield of nanoparticle formation. These AgNPs also exhibited the highest inhibition zone against Salmonella typhimurium and Staphylococcus aureus. The syntheses reported here have no significant influence on AgNPs physical characteristics, as compared to literature, but represent processes with shorter reaction time. Additionally, the fungal based nanoparticles have superior antibacterial characteristics.

IR super-resolution imaging of avian feather keratins detected by using vibrational sum-frequency generation

IR super-resolution imaging of the cross section of the rachis of an avian feather was carried out by using a vibrational sum-frequency generation (VSFG) detected IR microscope with a sub-micrometer spatial resolution. In the YYX polarization combination, we clearly observed strong signals in the entire region of the rachis at the amide I vibration of β-keratin. On the other hand, the signal disappears from most of the cross section in the XXY polarization combination. Because the VSFG imaging detects the signal only from the interface, we conclude that the interfacial deflection inside of a rachis was detected.

Atomic Force Microscopy Combined with Infrared Spectroscopy as a Tool to Probe Single Bacterium Chemistry.

Atomic Force Microscopy-Infrared Spectroscopy (AFM-IR) is a novel combinatory technique, enabling simultaneous characterization of physical properties and chemical composition of sample with nanoscale resolution. By combining AFM with IR, the spatial resolution limitation of conventional IR is overcome, enabling a resolution of 20-100 nm to be achieved. This opens the door for a broad array of new applications of IR toward probing samples smaller than several micrometers, previously unachievable by means of conventional IR microscopy. AFM-IR is eminently suited for bacterial research, providing both spectral and spatial information at the single cell and intracellular level. The increasing global health concerns and unfavorable future prediction regarding bacterial infections, and especially, rapid development of antimicrobial resistance, has created an urgent need for a research tool capable of phenotypic probing at the single cell and subcellular level. AFM-IR offers the potential to address this need, by enabling detail characterization of chemical composition of a single bacterium. Here, we provide a complete protocol for sample preparation and data acquisition of single spectra and mapping modality, for the application of AFM-IR toward bacterial studies.

Hydrothermal synthesized Nd-doped TiO2 with Anatase and Brookite phases as highly improved photoanode for dye-sensitized solar cell

In this study, the effects of Nd doping on the performance of TiO2 photoanode based dye-sensitized solar cells (DSSC) are reported. Nd-doped TiO2 (Nd-TiO2) was synthesized using hydrothermal method. Un-doped TiO2 (TiO2) was also synthesized for reference. XRD, IR, Raman and electron microscopy characterisation of the obtained material were performed and the subsequent electrochemical tests, CV and EIS studies were made to explore their application. The XRD and Raman analysis’s results indicated that the Nd-TiO2 and TiO2 have both the Anatase and Brookite phases. TEM, EDX and EIS studies were used to obtain particle size, morphology, the presence of the element, electron lifetime and recombination characteristics respectively. The Nd-TiO2 nanoparticles have uniform particle size, a strong red shift of their absorption into the visible region and greater dye-loading as compared with TiO2 nanoparticles. It is proved that higher efficiency was achieved when the TiO2 Anatase and Brookite structure were mixed. Further, Nd had a positive effect on the performance of photoelectrode and DSSC fabricated with Nd-TiO2 photoanode revealed an appreciable current conversion efficiency of 5.23% with a short-circuit current (Jsc) of 12.8 mA/cm2, open-circuit voltage (Voc) of 0.62 V and fill factor (FF) of 0.66. The increased current conversion efficiency was attributed to the greater dye loading, reduced charge recombination and facile charge transport with Nd-doped TiO2.

Detection of High-Explosive Materials within Fingerprints by Means of Optical-Photothermal Infrared Spectromicroscopy.

As we live under a constant threat of global terrorism, the effective detection of highly energetic materials is one of the critical procedures needed at a variety of locations, including airports, border checkpoints, and entrances to high-security buildings. In this work, the application of optical-photothermal infrared (O-PTIR) spectromicroscopy for the detection of highly explosive materials within fingerprints is described. High-explosive (HE) materials (e.g., PETN, RDX, C-4, or TNT) were used to prepare contaminated fingerprints. These were subsequently deposited on various objects, including microscopic glass slides, a table, a mug, etc. Samples deposited on glass slides were directly sent for analyses; for other samples, adhesive tapes were used to lift off fingermarks. In cases of difficulty in locating fingerprints, additional powders were used to enhance their visibility. Experiments were performed with a mIRage IR microscope working in a noncontact, far-field reflection mode, offering submicron IR spectroscopy and imaging. Fast imaging (several characteristic absorbances were selected for every substance of interest) was used to locate "suspicious" particles among various residues present in fingerprints. Subsequently, spectra were collected for those particles. Reflection mode O-PTIR spectra taken from powdered and nonenhanced fingerprints were of comparable quality to transmission mode FTIR spectra collected for pure HEs. On the basis of the performed experiments, we consider O-PTIR spectromicroscopy to open a new avenue for the nondestructive, efficient, and reliable analysis of exogenous substances deposited within fingerprints. The real significance of O-PTIR is in its ability to deliver high-quality, spatially resolved FTIR transmission-like spectra below the diffraction limit of infrared wavelengths, doing so in an easy-to-use reflection (far-field) mode. Collected spectra are also searchable and interpretable in both commercial and institutional IR databases without mathematical modeling.

Competition between N–H bending vibration and α-helix polarization under 50 Hz magnetic field in SH-SY5Y neuronal-like cells

The aim of this study is to investigate the causes of the different response of Amide I and Amide II bands in neuronal-like cells under an applied magnetic field at extremely low frequency and intensity. A Lumos IR microscope of Bruker Optics coupled with a FTIR spectrometer equipped with a wide-band liquid nitrogen cooled mercury–cadmium–telluride detector were used to acquire images and FTIR spectra of SH-SY5Y neuronal-like cells under exposure to 50 Hz magnetic fields at the intensity of 1.4 mT, generated by two Helmholtz coils driven by an AC voltage and placed into an incubator in a 5% CO2/95% air humidified at 37 °C. Using this experimental setup resulted that the Amide II vibration band in neuronal-like cells increased significantly more than Amide I band after 6 h exposure to 50 Hz magnetic fields. This result can be explained assuming that the following mechanisms occurred simultaneously after exposure to 50 Hz magnetic fields: the alignment of proteins α-helices in cellular membrane toward the direction of applied magnetic field and a significant increasing of N-H bending vibration in proteins structure.

Design, fabrication and optical characterizations of pyrimidine fused quinolone carboxylate moiety for photodiode applications

A novel ethyl 3-amino-2-cyano-6-hydroxy-7, 12-dioxo-2, 7, 12, 12a-tetrahydro-1H-benzo[g]pyrimido[1, 2-a]quinoline-5-carboxylate(3ABPQC)was synthesized by treating ethyl 2-amino-4-hydroxy-5, 10-dioxo-1, 5, 10, 10a-tetrahydrobenzo [g]quinoline-3-carboxylate 1 with methylidene malononitrile(2). Thin films of ABPQC were prepared to utilize thermal evaporation technique at room temperature under a certain condition for obtaining a high-quality film. The molecular, structural, and morphological characterizations were employed using Fourier transform IR, X-ray diffraction, and scanning electron microscopy. The analysis proved two available band gaps of 1.51 and 3.55 eV for the onset and optical gaps, respectively. The experimental optical gap was compared with those obtained using density functional theory (DFT). The spectral dependence of refractive index was explained based on single oscillator model and the main important parameters were extracted using the formula of Wemple and DiDomenico and found to be 2.91, 4.97, 0.34 and 0.21 for the oscillator energy, E0, dispersion energy, Ed, and the rth moments, M-1 and M-3, respectively. The remarkable optical behavior with the unique optical response representations of ABPQC allows designing and manufacturing organic- photodiodes based on ABPQC nanostructured films.

Electrochemical polymerization of para-chloroaniline as highly redox-active poly(para-chloroaniline) on graphitized mesoporous carbon surface

Owing to the high demand of conducting molecular systems for various electronics and technological applications, development of new polyaniline (PANI)/carbon nanomaterial is a continued research interest in cross-disciplinary area of material chemistry. In the literature, for the preparation of PANI/carbon nanomaterial composite electrode systems ex-situ preparation method, in which, chemical oxidation of aniline in presence of carbon nanomaterial, followed by modification on solid substrate has been widely adopted. In this work, a systematic study has been carried out for in-situ electrochemical polymerization of 4-chloroaniline and other substituted aniline monomers to respective PANI on graphitized mesoporous carbon (GMC), that show porous structure and enormous sp2 sites to aniline and PANI for π-π interaction, unusually in neutral pH condition. The new GMC@PANI modified electrode showed a highly redox active peak at Eo’ = 0.12 V vs Ag/AgCl in pH 7 phosphate buffer solution. No such behaviour was noticed when an unmodified glassy carbon was used as working electrode for the polymerization in the above mentioned condition. The redox peak is found to be stable, surface-confined and Nernstian type of proton-coupled electron-transfer in nature. Based on the physicochemical characterization techniques using Raman, IR, X-Ray photoelectron-spectroscopy, scanning electron-microscope and scanning electrochemical microscope (SECM) instruments and electrochemical studies with several ortho, para and meta substituted aniline monomers, mechanism for the in-situ polymerization has been revealed that 4-chloroaniline monomer has undergone a surface-confined electrochemical oxidation reaction with involvement of aniline(4-Cl)-cation radical species, anti-orientation of the monomer (that exist in solution phase), head-to-tail collision (C-N bonding), ejection of the para-substituents as Cl- and Cl•, partial chlorination and PANI(4-Cl) formation mechanism. Such a PANI(4-Cl) film showed a wave-like 2D molecular film structure with enhanced redox and electrical property over the conventional PANI system.

IR Microscopy as a Method for Studying the Influence of An External Electric Field on the Spin Crossover Exemplified by the Fe(II) Complex with 2,6-Bis(pyrazol-1-yl)pyridine

The influence of the electric field on the spin state of the single crystal of [Fe(1-Bpp)2][BF4]2 demonstrating the spin crossover phenomenon is studied. The spin state of the complex is determined by the indirect method: FT-IR microscopy. The experimental results show that the application of the external electrostatic field with an intensity of 13 kV/cm exerts no effect on the temperature of the magnetostructural transition of the compound within 0.2 K.

Cu(II) Ion Adsorption by Aniline Grafted Chitosan and Its Responsive Fluorescence Properties.

The detection and removal of heavy metal species in aquatic environments is of continued interest to address ongoing efforts in water security. This study was focused on the preparation and characterization of aniline grafted chitosan (CS-Ac-An), and evaluation of its adsorption properties with Cu(II) under variable conditions. Materials characterization provides support for the grafting of aniline onto chitosan, where the kinetic and thermodynamic adsorption properties reveal a notably greater uptake (>20-fold) of Cu(II) relative to chitosan, where the adsorption capacity (Qm) of CS-Ac-An was 106.6 mg/g. Adsorbent regeneration was demonstrated over multiple adsorption-desorption cycles with good uptake efficiency. CS-Ac-An has a strong fluorescence emission that undergoes prominent quenching at part per billion levels in aqueous solution. The quenching process displays a linear response over variable Cu(II) concentration (0.05–5 mM) that affords reliable detection of low level Cu(II) levels by an in situ “turn-off” process. The tweezer-like chelation properties of CS-Ac-An with Cu(II) was characterized by complementary spectroscopic methods: IR, NMR, X-ray photoelectron (XPS), and scanning electron microscopy (SEM). The role of synergistic effects are inferred among two types of active adsorption sites: electron rich arene rings and amine groups of chitosan with Cu(II) species to afford a tweezer-like binding modality.

All-digital histopathology by infrared-optical hybrid microscopy

Optical microscopy for biomedical samples requires expertise in staining to visualize structure and composition. Midinfrared (mid-IR) spectroscopic imaging offers label-free molecular recording and virtual staining by probing fundamental vibrational modes of molecular components. This quantitative signal can be combined with machine learning to enable microscopy in diverse fields from cancer diagnoses to forensics. However, absorption of IR light by common optical imaging components makes mid-IR light incompatible with modern optical microscopy and almost all biomedical research and clinical workflows. Here we conceptualize an IR-optical hybrid (IR-OH) approach that sensitively measures molecular composition based on an optical microscope with wide-field interferometric detection of absorption-induced sample expansion. We demonstrate that IR-OH exceeds state-of-the-art IR microscopy in coverage (10-fold), spatial resolution (fourfold), and spectral consistency (by mitigating the effects of scattering). The combined impact of these advances allows full slide infrared absorption images of unstained breast tissue sections on a visible microscope platform. We further show that automated histopathologic segmentation and generation of computationally stained (stainless) images is possible, resolving morphological features in both color and spatial detail comparable to current pathology protocols but without stains or human interpretation. IR-OH is compatible with clinical and research pathology practice and could make for a cost-effective alternative to conventional stain-based protocols for stainless, all-digital pathology.

Использование биомассы микроводорослей Chlorella sorokiniana в качестве энтеросорбента

This article presents an assessment of the biosorption capacity of Chlorella sorokiniana microalgae in relation to heavy metal ions (Zn2+, Cd2+, Pb2+, Cu2+) at various pH values. With the development of industry, several environmental threats have emerged, including heavy metal pollution. This form of pollution has negative effects in the short and long term on the health of animals and humans. To prevent the accumulation of harmful substances in the human body, it is advised to use oral sorbents in prophylactic and therapeutic purposes. Oral sorbents have the ability to adsorb and neutralize certain toxins in the stomach and the intestines and remove them from the human body. The present article investigated the possibility of using microalgae Chlorella sorokiniana as an oral sorbent. The sorption capacity of Chlorella sorokiniana microalgal biomass was determined by voltammetry of standard solutions with an initial concentration of heavy metal ions of 10 mg/L. The removal efficiency ranged from 88 to 99%. The studies were carried out at pH values from 2 to 6. The sorption capacity was high at all considered acidity values. Sorption properties were confirmed by the study of the IR spectrum and microscopy of the freeze-dried biomass samples. The surface of the sorption material was studied by electron microscopy depicting the presence of multiple pores and depressions. It could be assumed that the sorption properties of microalgae are partly due to physical processes. Freeze drying can significantly increase the active surface area of the sample. The presence of hydroxyl groups in the biomass was confirmed by IR-spectroscopy indicating the chemical nature of the sorption process.

Influence of Cotton Fiber Properties on the Microstructural Characteristics of Mercerized Fibers by Regression Analysis

This study is conducted on a raw material imported from several countries for the purpose of promoting the development of the world’s cotton spinning industry. If the time for selecting the raw material as well as the quality of the cotton spinning is improved, then time and money will be saved and the spinning industry will be improved. For this study, different cotton fibers were selected from different ecological regions. The cotton fibers were processed using the mercerization process, and then they were examined using X-ray diffraction (XRD), Fourier transform IR (FTIR) and scanning electronic microscope (SEM). High-volume instrument study was conducted to evaluate the physical properties of cotton fibers, including short fiber content, tensile strength, elongation at break, Micronaire value, and upper half mean length. In addition a change in fiber strength, the degree of crystallinity, and degree of orientation of cotton fibers before and after mercerization was also examined. SEM results show that the surface of cotton fibers became smooth and shiny after the treatment. FTIR and XRD revealed that the chemical composition did not change, but the degree of crystallinity decreased and the degree of orientation of alkalized cotton fibers increased after mercerization. In the second phase of this study, a correlation analysis was made between the physical properties of cotton fibers and the microstructural properties of alkalized cotton samples. This analysis revealed that the breaking strength of cotton fibers is strongly negatively correlated with the crystallinity of cotton fibers. The higher the tensile strength, the lower the crystallinity of cotton fibers, which leads to better mechanical properties of the end product. The degree of the orientation of cotton fibers is highly correlated with a tensile strength of cotton fibers. Xinjiang-Cn, BG-Au, and BG-Tu samples exhibited relatively better physical properties. BG-Au, BG-Tu, and Pakistan samples have higher values of tensile strength and lower values of yellowness; moreover, the raw material from these samples can be preferred according to correlation analysis. Correlation analysis between physical properties reveals that the tensile strength of cotton fibers is positively correlated with the Micronaire value; however, the correlation is not strong because of the lower value of the correlation coefficient as 0.4809.