Surface Characterization Of Materials Research Articles

Thermodynamic and experimental study on carbothermal reduction of JSC-1A lunar regolith simulant for metal and metalloid production

The carbothermal reduction of JSC-1A lunar simulant with activated carbon was investigated for producing metals and metalloids. Chemical equilibrium compositions were examined using Gibb’s free energy minimization to identify favorable operating temperatures at 0.1, 10-8, and 3 × 10-15 bar for Fe and Si production. Complete conversion of Fe2O3 to Fe(g) was predicted at temperatures above 850 °C and about 90 % conversion of SiO2 to Si(g) was predicted at temperatures above 1000 °C for lunar surface pressure of 3 × 10-15 bar. Thermogravimetry was used to examine the reactions with mixtures of JSC-1A and stoichiometric activated carbon in 100 % Ar up to 1500 °C, and comparisons between temporal mass losses and CO evolution were used to estimate volatile production. The results were compared to ultra-high vacuum experiments at ∼ 10-12 bar with temporal CO measured. Solid-state surface material characterization was performed using scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffractometry, and transmission electron microscopy to identify elemental distributions and particle morphology of sample surface before and after experiment as well as chemical compositions present after experiment. Changes in elemental distributions and morphologies of Si-, Fe-, and Ti- in the sample before and after the experiment provided strong evidence of reactions of Si-, Fe-, and Ti- compounds in JSC-1A. Characterization of the loose sample after TGA confirmed the presence of crystalline SiC, Si, and Fe. Deposits collected on Cu foils mounted above the sample in the ultra-high vacuum experiments were found to contain Fe-, Al-, Mg-, and Si- volatiles.

Dynamics of lithium plasma in laser-induced breakdown spectroscopy

Laser induced background spectroscopy (LIBS) is a very useful instrument for material surface characterization. Its usage for plasma facing tokamak components is envisaged in future machines. The calibration-free LIBS is also actively tested on existing tokamaks including Li covered surfaces. However, application of the most frequently used calibration-free Saha-Boltzmann technique for interpretation of LIBS results assumes local thermodynamic equilibrium (LTE) and plasma transparency for observed spectral lines. To investigate validity of this approach for Li plasma, we developed a hybrid model using 3DLINE, FEOS and THERMOS codes describing Li plasma formation, expansion, and radiation from the plasma plume. Using the model we reproduced quite well experimental measurements of Li lines radiation dynamics. Calculations show that transparency conditions can be very easily violated for Li LIBS plasmas, which absorbs up to 97% of 671 nm (Li I) line radiation. Other two easily observed in experiments lines, 548 nm (Li II) and 610 nm (Li I), remain relatively less affected by radiation absorption. We also notice that sharper focusing of the laser beam onto the surface makes the plasma more transparent. We believe that these conclusions are important to take into account while using LIBS for characterization of Li coated surfaces.

Surface characterization of cerium oxide catalysts using deep learning with infrared spectroscopy of CO

Characterization of material surfaces is crucial for understanding their properties and behavior. In this work, we utilized a deep learning technique, along with infrared (IR) spectrum of CO as a probe molecule, to explore the surface properties of cerium oxide (CeO2) catalysts. Through systematic density functional theory (DFT) investigation of CO-derived adspecies on various CeO2 facets, we obtained an extensive dataset containing vibrational frequencies, intensities, and adsorption energies of CO on CeO2. This dataset was used to synthesize large quantities of complex IR spectra to train deep learning models for predicting surface structures, including the distribution of CeO2 facets, CO-derived adspecies, and binding energies. These models were successful in analyzing experimental IR spectra of CO adsorbed on different types of CeO2, and their predictions were consistent with experimental observations in most cases. This work provides a machine learning approach in understanding the morphology, local environmental arrangement, interaction behavior of probe molecules, and catalytic characteristics of diverse CeO2 materials.

Constructing and evaluating the effect of micron-scale structures on von Willebrand factor damage

The incidence of clinical complication gastrointestinal bleeding has been proved as consequence of von Willebrand factor (VWF) damage after mechanical circulatory support in clinic. Many studies have been conducted to evaluate VWF damage, of which the most studied influencing factors are mechanical factors such as shear stress. However, in addition to mechanical factors, VWF damage may also be affected by interface factors. To address this issue, a roller pump circulation platform was established to investigate the effect of material surface micron-scale structures distribution on VWF damage in flow state. A composite micro-structure combining microngrating and micronpost was designed and constructed on the surface of Si wafer by lithography and reactive ion etching, and detailed characterization of material surfaces was also performed. Then the changes of VWF antigen, VWF ristocetin cofactor activity, and the degradation of high molecular weight VWF on these surfaces were investigated and compared. The results showed that, with the encryption of surface micro-structures arrangement, the material surface tends to be more hydrophobic, which is beneficial to reduce VWF damage. Therefore, in the design of material surface inside the mechanical circulatory support devices, it can be considered to add some surface micro-structures with a certain distribution density to change the hydrophilicity and hydrophobicity, so as to minimize the VWF damage. These results can provide important references for the evaluation of VWF damage caused by interface factors, and aid in designing material surface inside the mechanical circulatory support devices.

Synthesis of vinyl trimethyl silane and acrylic acid modified silica nanoparticles as corrosion inhibition protocols in saline medium

Metal corrosion is one of the detrimental processes in many areas which can lead to induce tremendous economic losses and reduce industrial production. Therefore, metal protection is becoming a technical, economical, and environmentally important approach for delaying the corrosion process. Nanomaterials functionalization is gaining high interest due to its outstanding engineering performance of material for anti-corrosion. In an aggressive medium such as seawater and 3.5 wt% NaCl (stimulated seawater) environments, stainless steels are widely utilized where the polymeric inhibitor could easily be incorporated on the metal surface. In this report, the biodegradable polymeric inhibitor has been newly grafted on mesoporous silica nanoparticles (MSN). The silane agent was grafted with polyacrylic acid vinyltrimethoxysilane (Si-PAA-VTMS) by reacting MSN with polyacrylic acid (PAA) and vinyltrimethoxysilane (VTMS). Furthermore, FTIR, SEM/EDX, AFM, and WCA measurements were applied for material surface characterization, adsorbed polymeric film, and corrosion properties of the prepared inhibitor. FTIR spectra displayed the presence of the carboxylic groups on the prepared Si-PAA-VTMS inhibitor indicating the successful synthesis. From SEM/EDX and AFM results, low porosity and dense double-layer coating of the polymer inhibitor were found on the surface morphologies which could effectively delay the rust formation. Hydrophobicity behavior was also examined after inhibitor adsorption onto the steel surface producing a higher water contact angle that repels the aggressive water content. Additionally, by utilizing optimum inhibitor concentration at 100 ppm, low corrosion rate (∼4.0–9.0 × 10−3 mm/year) and high inhibition efficiency (>80 %) were achieved at higher temperatures up to 60 °C.

Angle-Resolved Spectrophotometry for the Optical Characterization of Material Surfaces

Surface reflectance is a practical metric of the optical performance of a material. Applications, such as glass manufacturing, light sensing, satellite reflectors, and photovoltaics, depend on their reflectance properties and generalized optical performance. Reflectance measurements are rarely reported comprehensively, with only a single angle of incidence common in most datasets. Here, we present a new spectrophotometry system capable of performing angle-, wavelength-, and polarization-resolved reflectance measurements on various surfaces. Data from such a system yields significant information regarding the everyday, real-world performance of said materials. We perform exemplar studies by characterizing several standard thin-film antireflectance coatings and comparing the results to their known theoretical optical response. We also present results from measurements on an optical insulating material as well as a selection of wall paints to showcase the versatility of the technique. We highlight the parallels between measurement and theory, while analyzing the realistic implications of the measurements on their respective material’s practical performance under real-world conditions.

Analysis of the directivity of Longitudinal Critically Refracted (LCR) waves

The use of ultrasonic longitudinal critically refracted (LCR) waves is one approach used for near surface material characterization. It has been shown to be sensitive to stress and, in general, less sensitive to the effects of the texture of the material. Although the LCR wave is increasingly widely applied, in experiments the factors that influence the formation of the LCR beam are seldom discussed. This paper reports a new numerical model used to investigate the transducers’ parameters that can contribute to the directionality of the LCR wave and hence enable performance optimization when used for industrial applications. An orthogonal experimental method is used to study the sensitivity to the transducer parameters which influence the LCR wave beam characteristics. This method provides a design tool used to study and optimize multiple parameter experiments and it can identify which parameter or parameters are of most significance. The effects of incident angle, the aperture and the center frequency of the transducer were all studied. It is shown that the aperture of the transducer, the center frequency and the incident angle are the most important factors in controlling the directivity of the resulting LCR wave fields. The model was validated by comparision of data to those obtained with a finite element model. Experiments were also performed to confirm the numerical results. The model and experimental data provided improve understanding of the transducer selection and positioning in the optimization of LCR wave fields in experiments, which can be used to give signals which exhibit higher sensitivity for near-surface stress characterization.

Characterization of surface materials on African sculptures: new insights from a multi-analytical study including proteomics.

Multiple analytical techniques were used to characterize materials from the surfaces of two African sculptures in the collection of the Art Institute of Chicago: a Bamana power object (boli), and a Yoruba wooden sculpture of a female figure. Surface accretions on objects such as these have received relatively little scientific attention to elucidate their composition and function, in part because they are made with complex mixtures of natural materials, which are often unfamiliar and poorly represented in the scientific literature on artists' materials. For this reason, a complement of techniques including Fourier transform infrared spectroscopy and pyrolysis gas chromatography mass spectrometry were applied, along with shotgun proteomics to better understand the nature and biological origin, down to the species level, of the proteinaceous materials. The results highlighted the presence of diverse materials including plant resins, oils, polysaccharides, and inorganic (clay or earth) compounds. In particular, mass spectrometry-based proteomics provided new insights on proteinaceous components, allowing us to identify the presence of sacrificial blood, and more specifically, blood from chicken, goat, sheep and dog. This new scientific evidence supports and supplements knowledge derived from curatorial and field work studies, and opens new doors to understanding the objects' significance and history of use.

Hyperspectral and multispectral data fusion using fast discrete curvelet transform for urban surface material characterization

The objective of the present study is to analyze the quality of hyperspectral data fusion using low spatial hyperspectral (LSH) Airborne Visible InfraRed Imaging Spectrometer-Next Generation (AVIRIS-NG) 8 m data and high spatial multispectral (HSM) WorldView-3 image at 1.24 m remote sensing images with spectral unmixing technique. The resultant HSH data shows new prospects for urban surface material characterization with spectrally distinct classes. The spatial resolution of LSH is enhanced by injecting the high-frequency details from the corresponding HSM bands in fast discrete curvelet transform domain. The image fusion-based products’ quality has been analyzed by endmembers extraction and fractional maps generated using Piecewise Convex Multiple-Model Endmember Detection (PCOMMEND) method. Experimental results showed that the fusion has improved the spatial as well as spectral separability to extract the endmembers, particularly for the urban surface materials like the combination of water and asphalt, and bare soil and roof tiles.

Experimental investigations of threads surface integrity manufactured by cutting insert and with internal thread rolling head

The objective of this study was to provide insights for a deeply understanding of the threads surface integrity manufactured by cutting tap, rolling tap, cutting insert and with internal thread rolling head, using the multiscale surface texture and fractal analysis in order to show the performance of the internal rolling head by mechanical tests and also to highlight the advantages of rolling internal threads. A series of eight internal thread samples M80×1.5 manufactured by cutting insert and internal thread rolling head were analyzed on their surface texture characteristics and material properties. Surface characteristics of low carbon steel Ç1020 (equivalent to AISI 1020) were quantified by measuring four locations on regions of each sample. The threads made by cutting inserts and internal thread rolling head were subjected to tensile test and it was found that the average tensile load of threads made by internal rolling head is higher with 20% than the threads made by cutting insert. Furthermore, the internal thread sections of samples were analyzed using an optical projector by comparing the appearance of failed threads at low magnification to known failure modes, as well as scanning electron microscopy (SEM) for surface material characterization. It was found that it can be discriminate between the thread surface regions of samples manufactured by cutting insert and with internal thread rolling head, using area-scale analysis and surface texture characteristics. The surface micro-morphology results can be applied in studies about improving the lifetime of similar rolled threads and for mathematical modelling of lubrication processes between tool and workpiece.

Validation of a ground-based telescope-assisted hyperspectral remote sensor for soil measurements

The utility of the ground-based soil observation laser absorption spectrometer (SOLAS) was demonstrated through spectral reflectance measurements of five soil types during laboratory- and field-based collection. The SOLAS telescope-assisted measurements were compared with proximal measurements. The spectra that were acquired at an intermediate range of 40 meters compared well with the spectra that were acquired proximally. Specimen type, range-dependent spatial resolution, and environmental conditions are discussed. The signal-to-noise ratio (SNR) was assessed and is presented as a function of wavelength for the spectral range of the receiver for each measurement condition. The proximal measurements performed outdoors under solar illumination had the greatest SNR, while the remote measurements performed indoors under artificial illumination had the lowest SNR. For the outdoor measurements, loss of signal was observed around the 1400- and 1900-nm bands due to long-path atmospheric water vapor absorption. The discussed future improvements to the SOLAS remote sensor will enable measurements of reflectance over longer ranges. Envisioned applications include remote characterization of surface materials for large construction projects (e.g., surface mines and tailings) for geohazard investigations, or for ground truthing of current and future multispectral and hyperspectral satellite data.

Multiscale surface texture and fractal analysis of straight bevel gears finished by PECH and PECF process

ABSTRACTThe present work was conducted to provide insights for an in-depth understanding of the straight bevel gears finished by pulsed-electrochemical-honing (PECH) and pulsed-electrochemical-finishing (PECF), using multi-scale surface texture and fractal analysis in order to give manufacturers a competitive edge when improving their tools. Unfinished bevel gears and bevel gears finished by PECF and PECH were analyzed on their surface texture characteristics and material properties. Surface characteristics of 20MnCr5 alloy steel gears were evaluated by computing four locations on regions of each sample. Field emission scanning electron microscopy (FESEM) was applied for surface material characterization. It was found that it can be discriminated between the PECF and PECH-finished bevel gears surface regions of samples and unfinished samples, using area-scale analysis and surface texture characteristics. The surface micro-morphology results can be applied in studies about improving the lifetime of tools and for mathematical modeling of lubrication processes between tool and workpiece.

VALIDATION OF EXTRACTED ENDMEMBERS FROM HYPERSPECTRAL IMAGES

Abstract. An essential step in the characterization of surface materials using hyperspectral image analysis is image classification using endmembers. Spectral unmixing is the best method for hyperspectral image classification. This method assumes that the pixel-topixel variability in scene results from varying proportions of spectral endmembers. Spectral endmembers can be derived from the imagery or measurements in the laboratory or field. The primary objective of this paper was to assess the ability of extracted endmembers against some different solutions for extraction of endmembers for hyperspectral image classification. In this paper, we compared the Pixel Purity Index (PPI) and the Sequential Maximum Angle Convex Cone (SMACC) as two popular methods of endmember extraction with library and field spectral. We used spectral information divergence for detection desirable endmembers from field spectral. For accuracy assessment of spectral mixture analysis and production of endmember abundance images for each of methods, the linear spectral unmixing algorithm is used. After a comparison between the results of these methods, it has been verified that field spectral have a better classification result in comparing with other endmember extraction methods. Also, the PPI has reliable results as an automatic endmember extraction method in comparing.

Integrating Remotely Sensed and GIS Data for the Detailed Geological Mapping in Semi-Arid Regions: Case of Youks les Bains Area, Tebessa Province, NE Algeria

Detailed geologic mapping provides valuable informations about the spatial distribution of lithological outcrops and lineaments; required to carry out the necessary investigations of the geologic, geotechnical and hydrogeological data investigation. The unavailability of geologic coverage at meduim scale in the Nementcha mountains has severely hampered geoscientist to develop and test their hypotheses. In order to exploit multispectral datasets for the characterization of surface materials; Sentinel-2A data was used in the discrimination of geological classes along Youks les Bain area, extreme NE of Algeria. Resampling, orthorectification, atmospheric correction, and radiometric normalization have been applied to the Sentinel-2A radiance data, identified as the first and most important step in processing. The 12/4, 11/3 and 8/4 band ratios combination was adopted to discriminate the different lithologies. Then, to reduce redundant information in highly correlated bands, the principal component analysis has been implemented. The directional filters were applied to undertaken the lineamentary mapping. At last the project was exported and processed in GIS spatial database. The result allows the discrimination of the lithological boundaries and help to a better understanding of the local geology of the study area. The project digital databases represents a key tool to support research activities in the West of Tebessa region.

Prediction of perceived quality through the development of a robot-supported multisensory measuring system

Knowing how customers perceive the quality of a product before it is on the market – this is a dream of every company. Thus, this paper shows an approach to realize the prediction of perceived quality through the development of a robot-supported multisensory measuring system.Today’s products are highly sophisticated and almost interchangeable in terms of their technical properties and functional quality aspects. Therefore, the perceived quality is becoming increasingly important to product designers. It is no longer sufficed to develop a product that addresses the functional requirements of the customer, a product must at the same time correspond to the sensory perception. The sensory design of products plays an important role in the customer’s overall assessment of quality. Sensory design so far considers visual, acoustic and haptic aspects of a product mostly separately, however the human perception is inherently multisensory as well as multimodal by nature thus the combined evaluation is inevitable.The aim of this paper is the development of a robot-supported multisensory measurement system to predict the perceived quality of surface materials by means of machine learning.Literature provides approaches, which are mostly based on human studies, to record customer’s subjective perception in order to derive design specifications for the product development process. This paper pursues, in addition to the subjective studies, the approach to make the multisensory perception tangible and objective by alternative metrological solutions. The multisensory measuring system for surface material characterization fuses haptic, optical and acoustic sensors according to the human stimulus processing chain. Subsequently, the objective measurement data is linked with the subjective data via machine learning algorithms in order to predict the perceived quality. This approach can be utilized in the product development process to forecast which materials create a value for the customer.

Immobilization of type I collagen/hyaluronic acid multilayer coating on enoxacin loaded titania nanotubes for improved osteogenesis and osseointegration in ovariectomized rats.

Titania nanotubes (Ti-NTs) have been proven to be good drug carriers and can release drugs efficiently around implants. Enoxacin (EN) is a broad-spectrum antibiotic that has the ability of anti-osteoclastogenesis. Immobilization of extracellular matrix components on the surface of the material can greatly enhance the biological activity of the implant and slow down the release rate of the drug in Ti-NTs. In the present study, a material system that provided uniform drug release, promoted osteogenesis, and inhibited osteoclast was designed and developed. Scanning electron microscopy, X-ray photoelectron spectroscopy, and water contact angle measurements were used for material surface characterization. Enoxacin release was detected by high performance liquid chromatography. Alkaline phosphatase and Alizarin Red staining were used to evaluate the osteogenic differentiation of rat bone marrow mesenchymal stem cells. Tartrate-resistant acid phosphatase staining and bone absorption assay were applied to osteoclastogenesis experiments. A drug delivery system based on Ti-NTs and type I collagen /hyaluronic acid multilayer coating (Ti-NT+EN+Col/HyA) with predominant biocompatibility, osteogenic property, and anti-osteoclastogenesis ability was successfully constructed. These excellent biological properties were further validated in an ovariectomized rat model. The results of the study indicate that Ti-NT+EN+Col/HyA is a potential material for future orthopedic implants.

Nitrogen-doped graphene supported Cu-Ag2.9 nanoparticles as efficient methanol tolerant cathode for oxygen reduction

Highly dispersed nanoparticles (NPs) of Cu, Ag and their composites are obtained on nitrogen-doped graphene nanosheets (N-GNS) using a microwave-assisted polyol reduction method. Structural, electrochemical and electrocatalytic surface characterization of materials have been carried out by TEM, XRD, XPS, cyclic (CV) and linear sweep (LSV) voltammetries. The study shows that the crystallites of the Cu-Ag composite follow the face-centered cubic (fcc) crystal structure. Further, the catalytic activities of Cu/N-GNS and Ag/N-GNS towards oxygen reduction reaction (ORR) are greatly enhanced when Cu and Ag are dispersed on the N-GNS surface in 1:2.9 M ratio. The active composite material does not oxidize methanol practically and has outstanding stability under ORR condition.

Hybrid AFM for Nanoscale Physicochemical Characterization: Recent Development and Emerging Applications.

Atomic force microscopy (AFM) has evolved to be one of the most powerful tools for the characterization of material surfaces especially at the nanoscale. Recent development of AFM has incorporated a suite of analytical techniques including surface-enhanced Raman scattering (SERS) technique and infrared (IR) spectroscopy to further reveal chemical composition and map the chemical distribution. This incorporation not only elevates the functionality of AFM but also increases the resolution limitation of conventional IR and Raman spectroscopy. Despite the rapid development of such hybrid AFM techniques, many unique features, principles, applications, potential pitfalls or artifacts are not well known to the community. This review systematically summarizes the recent relevant literature on hybrid AFM principles and applications. It focuses specially on AFM-IR and AFM-Raman techniques. Various applications in different research fields are critically reviewed and discussed, highlighting the potentials of these hybrid AFM techniques. Here, the major drawbacks and limitations of these two hybrid AFM techniques are presented. The intentions of this article are to shed new light on the future research and achieve improvements in stability and reliability of the measurements.

Geometrical roughness analysis of cement paste surfaces using coherence scanning interferometry and confocal microscopy

In this paper, geometrical roughness numbers named RNx, RNy and RNS are formulated as a possible analytical tool for cement-based material surface characterization using coherence scanning interferometry (CSI) and STIL confocal microscopy technique (SCM). Recently, cement paste surface maps have been used to establish a link between surface statistical roughness parameters and the measuring scale (Apedo et al., 2015). The objectives of the present paper are to study how geometrical roughness numbers can be used as a tool to analyze the colonization of cement-based material surfaces by microorganisms as well as to perform other subsequent studies. Observations from a series of images acquired using both techniques (CSI and SCM) on both polished and unpolished samples are described. Using a new method named “window resizing”, the results from CSI are compared with those from SCM. It appears that the surface available for colonization (convolution) is smaller than the surface developed by the measuring tool (sampling). The new method also allows the identification of the fractal regions and the associated fractal dimensions of both polished and unpolished cement pastes.

Surface fractal dimension, water adsorption efficiency, and cloud nucleation activity of insoluble aerosol.

Surface porosity affects the ability of a substance to adsorb gases. The surface fractal dimension D is a measure that indicates the amount that a surface fills a space, and can thereby be used to characterize the surface porosity. Here we propose a new method for determining D, based on measuring both the water vapour adsorption isotherm of a given substance, and its ability to act as a cloud condensation nucleus when introduced to humidified air in aerosol form. We show that our method agrees well with previous methods based on measurement of nitrogen adsorption. Besides proving the usefulness of the new method for general surface characterization of materials, our results show that the surface fractal dimension is an important determinant in cloud drop formation on water insoluble particles. We suggest that a closure can be obtained between experimental critical supersaturation for cloud drop activation and that calculated based on water adsorption data, if the latter is corrected using the surface fractal dimension of the insoluble cloud nucleus.