Blocky Structures Research Articles

Microstructural evolution and fracture behaviour of dissimilar Al/Steel lap joints by laser beam oscillating welding

ABSTRACT The hybrid metal joining of aluminium alloy and steel has become the most intensively used candidate material for energy conservation and emission reduction in the automotive industry because of the comprehensive properties of low density, high strength and good corrosion resistance. In this work, experimental investigations were conducted on the laser beam oscillation welding of galvanised steel and aluminium alloy arranged in a lap configuration. Well-formed joints were successfully obtained with the aid of beam oscillating. Zigzag structures were observed at the interfacial area of Al–Fe joints instead of blocky structures due to the oscillation-driven effect of the beam. The stirring effect of the oscillating beam can promote the migration of the solute during the laser welding process, thus inhibiting the separation of components and decreasing the vulnerability to cracking. The interface zones of the laser-welded Al–Fe joints were principally made up of the Fe2Al5, FeAl, FeAl2, FeAl3 and Fe2Al5Zn0.4 phases. The joints welded with beam oscillation exhibited a tensile load and elongation amount of 1.07 kN and 0.775 mm, respectively, representing 115.67% of the loading capacity and 119.23% of the elongation compared to laser beam-welded joints without oscillation.

Collapse analysis of masonry arches and domes considering finite friction and uncertainties in compressive strength

Within the context of the lower bound theorem of classical limit analysis, the collapse of stone masonry arches and domes characterized by finite friction and uncertain finite compressive strength is addressed. Self-weight is considered, along with a live point load applied at the crown. A multi-constrained funicular approach based on the concept of force densities is implemented to provide the maximum static load multiplier for any assigned value of the friction coefficient and of the compressive strength. The numerical method, which takes into full account the stereotomy of blocky stone structures, is validated by using a novel version of the semi-analytical Durand-Claye’s stability area method. Two different types of brickwork are considered in the investigation, addressing the compressive strength as a random variable with prescribed log-normal distributions. Due to the limited availability of data to elaborate probabilistic models for the angle of friction, the effect of this mechanical parameter on the probability of failure of the blocky structures is assessed by developing a set of fragility curves. For each discrete value in a representative range of friction coefficients, a Monte Carlo investigation is performed by iteratively applying the funicular method considering samples of the random variable that describes the compressive strength. The retrieved load multipliers are processed to estimate the probability of failure for any given magnitude of live load, which depends on the value of the friction coefficient. An insight into the collapse modes occurring in the masonry arches and domes under examination is provided, as well.

Preparation and characterization of astaxanthin-loaded microcapsules stabilized by lecithin-chitosan-alginate interfaces with layer-by-layer assembly method

Astaxanthin is a kind of keto-carotenes with various health benefits. However, its solubility and chemical stability are poor, which leads to low bio-availability. Microcapsules have been reported to improve the solubility, chemical stability, and bio-availability of lipophilic bioactives. Freeze-dried astaxanthin-loaded microcapsules were prepared by layer-by-layer assembly of tertiary emulsions with maltodextrin as the filling matrix. Tertiary emulsions were fabricated by performing chitosan and sodium alginate electrostatic deposition onto soybean lecithin stabilized emulsions. 0.9 wt% of chitosan solution, 0.3 wt% of sodium alginate solution and 20 wt% of maltodextrin were optimized as the suitable concentrations. The prepared microcapsules were powders with irregular blocky structures. The astaxanthin loading was 0.56 ± 0.05 % and the encapsulation efficiency was >90 %. A slow release of astaxanthin could be observed in microcapsules promoted by the modulating of chitosan, alginate and maltodextrin. In vitro simulated digestion displayed that the microcapsules increased the bio-accessibility of astaxanthin to 69 ± 1 %. Chitosan, alginate and maltodextrin can control the digestion of microcapsules. The coating of chitosan and sodium alginate, and the filling of maltodextrin in microcapsules improved the chemical stability of astaxanthin. The constructed microcapsules were valuable to enrich scientific knowledge about improving the application of functional ingredients.

Study on the effect of graphite-based materials on the reactivity of activated aluminum composites in different forms of water

For further energy enhancement of water-reactive metal fuels, it is crucial to find aluminum composites that can react synchronously and quickly with multiple types of water (ice, steam, and water). In this paper, two graphite-based aluminum composites, aluminum/bismuth/graphite (Al/Bi/GI) and aluminum/bismuth/graphene nanosheets (Al/Bi/GE), were prepared. The morphology and crystal structure of the composites were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The reactivity of Al/Bi/GI and Al/Bi/GE with water from 20 °C to 80 °C and ice at 0 °C and −15 °C was characterized using hydrogen generation properties. Their ignition and combustion properties in high-temperature water steam from 300 °C to 900 °C were also investigated. The results show that Al/Bi/GI and Al/Bi/GE composites prepared by ball milling have blocky and multilayered lamellar structures, respectively. That ball milling does not result in the formation of new alloys. The thickness of graphite material affects the reactivity of activated aluminum composites. The hydrogen generation rates of Al/Bi/GE in water and ice are much higher than that of Al/Bi/GI. The maximum hydrogen generation rates of Al/Bi/GE were 28.8 and 46.6 times higher than those of Al/Bi/GI in water at 20 °C and ice at −15 °C, respectively. In high-temperature water steam, the ignition temperature and ignition delay time of Al/Bi/GE are lower than those of Al/Bi/GI. Al/Bi/GE achieves a rapid reaction that can be synchronized with three forms of water and is expected to be applied to water-reactive metal fuel propellants.

Structure and luminescence properties of Li<sub>2</sub>Gd<sub>4</sub>(MoO<sub>4</sub>)<sub>7</sub>:Sm<sup>3+</sup> orange-red phosphor for solid-state lighting

White LEDs have the broad application prospect and market demand, while the red phosphor can greatly affect the color temperature and color rendering index of the modulated white light. In this work, a series of Li<sub>2</sub>Gd<sub>4–<i>x</i></sub>Sm<sub><i>x</i></sub>(MoO<sub>4</sub>)<sub>7</sub>(<i>x</i> = 0.01—0.13) phosphors is prepared by the high-temperature solid phase method. The successful doping of Sm<sup>3+</sup> into Li<sub>2</sub>Gd<sub>4</sub>(MoO<sub>4</sub>)<sub>7</sub> is confirmed by X-ray diffractometry (XRD) and does not lead to any change in crystal structure. The samples are detected by scanning electron microscope (SEM) to have irregular blocky structures with particle size less than 20μm. The existence of Li, Gd, Mo, O and Sm elements in the phosphor is confirmed by energy dispersive X-ray spectroscopy (EDS). The observation of X-ray photoelectron spectroscopy (XPS) shows that the activators are successfully doped into materials. Under 406 nm excitation, the emission peaks of the samples are located at 563, 598, 645 and 706nm respectively, which are caused by the 4f-4f transition of Sm<sup>3+</sup>, and the strongest emission peak comes from <sup>4</sup>G<sub>5/2</sub>→<sup>6</sup>H<sub>9/2</sub> transition. It is found that optimal concentration of Sm<sup>3+</sup> is 0.07. With the increase of Sm<sup>3+</sup> concentration, the fluorescence lifetime decreases gradually. The temperature-dependent emission of phosphor is also studied. The emission intensity at 473 K is still 79% of that at 298 K, indicating that the sample has excellent heat resistance. The CIE chromaticity diagram shows the luminescence of the prepared phosphor is located in the orange-red region and the color purity is high (99%). Moreover, a white LED is fabricated using the optical doped phosphor, which has CIE coordinates of (0.3788, 0.3134) that are located in the circle of white light. Research shows that the Li<sub>2</sub>Gd<sub>4</sub>(MoO<sub>4</sub>)<sub>7</sub>:Sm<sup>3+</sup> phosphor is a promising orange-red phosphor for white LEDs.

Insight into austenite reversion and mechanical behavior of quenching and partitioning steel inherited hierarchical structure of martensite

In this paper, the start microstructure of full martensite and dual phases comprising ferrite and martensite were introduced into quenching and partitioning (Q&P) steel to tailor the microstructural characteristics and mechanical behaviors, which was achieved by means of a pre-quenching treatment with various temperatures. It is revealed that the conventional Q&P sample possessed bimodal microstructure with predominantly blocky feature, while gradually changed from combination of blocky and lath structures into individually lath feature in pre-quenched Q&P samples. The reversed austenite presented different variants, which predominantly reproduced the orientation of parent austenite and occasionally possessed twin relationship, low angle misorientation or extraneous with parent austenite. The twin-related austenite included annealing twin and reversed twin, whilst the latter showed twin relationship with both neighbored annealing twin and parent austenite. The variant type of reversed austenite significantly influenced the characteristics of its orientation relationship with neighbored pre-quenched martensite. The pre-quenching treatment was favorable to improve the carbon content of meta-stable austenite before Q&P treatment, while the final carbon content in retained austenite was mainly controlled by the synergistic carbon partitioning of martensite and bainite on basis of thermodynamic calculation, accompanied with the partitioning of Mn and Si elements. Moreover, the pre-quenched martensite deformed coordinately in a unit of martensite packet and was beneficial to retard necking to improve ductility. The optimal mechanical properties were obtained with pre-quenching temperature near Ac3, possessing yielding strength of 623 MPa, ultimate tensile strength of 861 MPa and product of strength and elongation exceeding 28 GPa%, attributing to the positive TRIP effect originating from lath-like retained austenite with high carbon content and multi-level hierarchical microstructure inherited from pre-quenched martensite.

Investigation on the Ni60-WC composite coatings deposited by extreme-high-speed laser-induction hybrid cladding technology: Forming characteristics, microstructure and wear behaviors

In this work, Ni60-WC composite coatings with 35 wt% WC (Ni65-WC35), 50 wt% WC (Ni50-WC50) and 65 wt% WC (Ni35-WC65) were deposited by the extreme-high-speed laser-induction hybrid laser cladding technology (EH-LIHC), and the forming characteristics, microstructure, hardness and wear behaviors were investigated systematically. Results indicated that all the EH-LIHCed Ni60-WC coatings displayed low-roughness surfaces and even-distributed WC particles, where the dilution ratio and WC's heat-loss increased with the rise of induction heating temperature (T) and WC's content. Crack-free single-layer Ni60-WC coatings could be obtained at T ≥ 600 °C, whereas some micro-cracks were inevitably induced during the multi-layer depositions. The WC particles mainly presented the decomposition/ dissolution-diffusion, collapse-dissolution and decomposition/dissolution-precipitation heat damages, corresponding to the W-rich dendritic/wing-like/filamentary structures, dendritic facet structures and blocky facet structures on the metal matrix, respectively. Under both loading forces of F = 50 N and 80 N, the wear rates Ni60-WC composite coatings presented the order of Ni35-WC65 < Ni65-WC35 < Ni50-WC50. Spalling of the matrix, cracking and crushing of the WC particles were detected on all worn surfaces. The Ni35-WC65 coating possessed the highest contents of WC particles and facet carbides, making its damage threshold and wear resistance enhanced significantly. Nonetheless, the wear debris in Ni65-WC35 coating had formed a metal layer covering on the worn surface, helping to alleviate the damage of the beneath WC particles significantly, therefore it possessed lower wear rate than that of Ni50-WC50 coating.

Rock Mass Characterizations and Kinematic Analysis for Construction Design Method of Diversion Tunnel of Dolok Dam, Central Java

Investigation of slope stability in the design of the tunnel portal is important to minimize slope failure. This research aims to describe the rock mass characterizations and classifications using Geological Strength Index (GSI) and Rock Mass Rating (RMR), along with the kinematic analysis and Slope Mass Rating (SMR) to define the risk of slope failure and the recommended support at the tunnel portal. Geological mapping and core evaluation were conducted to analyse the slope stability. The results show that the rock masses consist of intercalated rudstone with mudstone, typically have disintegrated, moderately disturbed, and blocky structures with slightly to highly weathered. The discontinuities have 3 – 4 sets consisting of bedding and joint, have medium to high persistence, close spacing, and dominantly have no infillings. These rock masses are classified as poor-fair rock in the upper part of the sequence, and good rock in the bottom part of the sequence. The kinematic analysis predicts the risk of toppling failure both in the inlet and outlet portal. The recommended support in the inlet portal is the combination of shotcrete, beams, and bolts, whilst in the outlet portal is the combination of surface drainage, shotcrete, dental concrete, beams, and bolts.

Evaluation of Physical Characteristics of Soils Derived from Basement Complex Rocks of the Jos Plateau

The physical characteristics of soils to a large extent influences soil productivity. The objective of this study therefore is to evaluate the physical characteristics of soils derived from basement complex rocks of the Jos Plateau. According to the methodology outlined in the Soil Survey manual, the stratification of the study region into three geologic units—granite gneiss, biotite granite, and migmatite—was the first step in the soil research process. Additionally, soil samples were collected from genetic strata and soil profile pits were dug in each of these geologic units. Following standard procedure soils were analyzed for color, particles size distribution, structure, and bulk density. Results indicated that physical soil characteristics over the geologic units studied were in most cases similar. However significant differences were observed in particle size distribution in the A-horizons. Clay content in the A horizon of these soils generally ranged from a minimum of 8% to a maximum of 28%. Clay content in the A-horizons of the magmatic soils were significantly higher (P&lt;0.05) than soils over granite gneiss but statistically similar (P&gt;0.05) to those of biotite granite. Particle size distribution data indicate that the soils have undergone intensive weathering. Soil structures were on the average moderately developed in the soils studied with angular and sub-angular blocky structures. Although there was evidence of soil compaction to suggest plant root development could be affected or inhibited in these soils. .

Nanoindentation on the Transformation of LPSO Phases during Different Solution Heat Treatments in an Mg-Dy-Nd-Zn-Zr Alloy

The objective of this study is the investigation of nanomechanical properties using nanoindentation of extruded and heat-treated Mg-Dy-Nd-Zn-Zr, with an emphasis on the transformation of long-period stacking-ordered (LPSO) phases. Solution heat treatment was performed with different heat treatment for durations on hot extruded Mg-Dy-Nd-Zn-Zr to monitor the transformation of LPSO phases, as well as to keep track of microstructural changes. The initial fine-grained microstructure, with blocky and lamellar LPSO structures within the matrix, first transformed into coarser grains with fewer LPSO lamellae, which then increased in amount again at higher annealing duration. The blocky LPSO phases, which have the highest hardness compared to the matrix grains with and without LPSO lamellae, consistently decrease in quantity, as so does the trend in their hardness value. The Mg matrix grains with LPSO lamellae show a lower hardness compared to the Mg matrix grains without or with a just few lamellar LPSO phases, and increase in quantity at long annealing durations. The overall hardness of the microstructure is essentially determined by the LPSO lamellae-containing grains and reaches a peak at 24 h. There is another peak found for the grain size values; however, this is at later annealing duration, at 72 h. The reduction in grain size towards longer annealing durations goes along with a reactivated formation of LPSO lamellae.

THE EFFECT OF THE SEDIMENTS OF THE HILLA RIVER ON THE CHARACTERISTICS OF THE ADJACENT SOILS (BABYLON GOVERNORATE)

This study was conducted to investigate the effect of the sediments of the Hilla River on the characteristics of some the sedimentary soils adjacent to the Hilla River, the sampling sites were chosen in the study area along the eastern side of the Hilla River, which extends from the beginning of its branching from the Euphrates River at the front of the Hilla dam in the province of Babil and along the river in the south, all the way to the back of the Sadr alDaghara regulator, which is located between the provinces of Babel and Al-Diwaniyah. Fifteen pedons were excavated, distributed in five transects perpendicular to the Hilla River. Each transect contains three pedons and represents a unit of shoulder, basin and depression. The results of soil investigations showed that there is a difference in some soil morphological properties among the studied sites according to the shape of the land, it was noted that there was no difference in the Hue through the wavelength of the studied sites and it was 10YR, with a difference in the Value and Chroma among all the pedons of the study area with depth, and indicates that the same sedimentation source (River Hilla). The predominance of the two types of blocky structures (angular blocky and sub angular blocky) and this shows the effect of the type of sediment. The results of the physical analysis showed a variation in the soil texture for both vertical and horizontal directions with the predominance of silt and sand particles and a decrease in the percentage of clay particles and this depended on the sedimentation speed associated with the proximity or distance of the river. As for the bulk density, its values also have changed as a result of a variation in the volume distribution ratio of soil particles of sand, silt and clay. While the results of the chemical analysis indicated that there is a difference in the chemical properties of soils in all study transects with depth, pH values lie between neutral to moderately basic (6.85-8.19) within the normal range of Iraqi soils, the electrical conductivity ranged between (0.68-36.2 ds m-1) from low salinity soils to very high salinity soils. As for SAR, it was low in sodium in most of the study pedons with depth, reaching 2.35, (medium to very high in some sites), and the values of the CEC ranged between (7.49- 21.45) Cmol Kg-1, As for the soil content of total calcium carbonate (CaCO3), whose values ranged between (6.52-22.17)%, the highest value of the soil content of organic matter reached in most of the surface horizons compared with the subsurface horizons

Horseradish peroxidase catalyzed grafting of chitosan oligosaccharide with different flavonols: structures, antioxidant activity and edible coating application.

Enzymatic catalyzed grafting of oligosaccharides with polyphenols is a safe and environmentally friendly approach to simultaneously enhance the bioactivity of oligosaccharides and the solubility of polyphenols. In this study, chitosan oligosaccharide (COS) was grafted with three different flavonols including myricetin (MYR), quercetin (QUE) and kaempferol (KAE) by horseradish peroxidase (HRP) catalysis. The structures, antioxidant activity and edible coating application of COS-flavonol conjugates were investigated. The total phenol content of COS-MYR, COS-QUE and COS-KAE conjugates was 59.89, 68.37 and 53.77 mg gallic acid equivalents g-1 , respectively. Thin layer chromatography showed the conjugates did not contain ungrafted flavonols. COS-flavonol conjugates showed ultraviolet absorption peak at about 294 nm, corresponding to the A-ring of flavonols. Fourier-transform infrared spectra of conjugates confirmed the formation of Schiff-base and Michael-addition products. The proton-nuclear magnetic resonance spectrum of COS-KAE conjugate exhibited phenyl proton signals of KAE. X-ray diffraction patterns of conjugates showed some diffraction peaks of flavonols. COS-flavonol conjugates presented rough and porous morphologies with sheet-like and/or blocky structures. The conjugates showed higher water solubility, free radical scavenging activity and reducing power than flavonols. Moreover, fish gelatin/COS-flavonol conjugate coatings effectively prolonged the shelf life of refrigerated largemouth bass (Micropterus salmoides) fillets from 5 days to 7-8 days. COS-flavonol conjugates prepared by HRP catalysis have great potentials as novel antioxidant agents. © 2022 Society of Chemical Industry.

EBSD Analysis of Blocky Structures in Hardened and Tempered Microstructures of a 5 wt.% Cr Cold Work Tool Steel

The hardened microstructure of 5 wt.% Cr cold work tool steels is mainly martensitic with significant amount of retained austenite and some undissolved carbides. Whereas the microstructure after tempering shows significant amounts of angular shaped blocky regions, which are interpretated as retained austenite or fresh martensite. The distinction between the phases is difficult due to the morphological similarities. Therefore, the blocky regions are characterized by electron backscatter diffraction to better understand the microstructures. The results showed that the characterisation of blocky structures in the microstructure of a 5 wt.% Cr cold work tool steels varied according to the austenitisation and tempering temperatures as well as the holding time at the tempering temperature. Electron backscatter diffraction of as-quenched microstructures revealed that the blocky structures were either retained austenite, fresh martensite or a combination of large part of fresh martensite with minute amounts of retained austenite. The blocky structures were entirely retained austenite after tempering at 200 °C. Tempering at 525 °C, for holding times of 0.1 or 0.5 h, more blocky regions were retained austenite contrasting to the blocky regions for holding times of 1 or 2 h, which were largely fresh martensite. It was further concluded that electron backscatter diffraction is a suitable technique for characterisation of blocky structures provided that the specimens are prepared by electro-polishing while X-ray diffraction is best suited for a bulk measurement of retained austenite.

An Innovative Digestion Method: Ultrasound-Assisted Electrochemical Oxidation for the Onsite Extraction of Heavy Metal Elements in Dairy Farm Slurry

Dairy farm slurry is an important biomass resource that can be used as a fertilizer and in energy utilization and chemical production. This study aimed to establish an innovative ultrasound-assisted electrochemical oxidation (UAEO) digestion method for the rapid and onsite analysis of the heavy metal (HM) contamination level of dairy slurry. The effects of UAEO operating parameters on digestion efficiency were tested based on Cu and Zn concentrations in a dairy slurry sample. The results showed that Cu and Zn digestion efficiency was (96.8 ± 2.6) and (98.5 ± 2.9)%, respectively, with the optimal UAEO operating parameters (digestion time: 45 min; ultrasonic power: 400 W; NaCl concentration: 10 g/L). The digestion recovery rate experiments were then operated with spiked samples to verify the digestion effect on broad-spectrum HMs. When the digestion time reached 45 min, all digestion recovery rates exceeded 90%. Meanwhile, free chlorine concentration, particle size distribution, and micromorphology were investigated to demonstrate the digestion mechanism. It was found that 414 mg/L free chorine had theoretically enough oxidative ability, and the ultrasound intervention could deal with the blocky undissolved particles attributed to its crushing capacity. The results of particle size distribution showed that the total volume and bulky particle proportion had an obvious decline. The micromorphology demonstrated that the ultrasound intervention fragmented the bulky particles, and electrochemical oxidation made irregular blocky structures form arc edge and cellular structures. The aforementioned results indicated that UAEO was a novel and efficient method. It was fast and convenient. Additionally, it ensured digestion efficiency and thus had a good application prospect.

Black clayey soil (Vertisol) in the Lerma valley, Michoacán, North‐Central Mexico: A hint of the environmental and cultural changes during the Late Classic period?

AbstractCatastrophic events (climatic, tectonic, volcanic, etc.) frequently cause geomorphological instability, which interrupts normal pedogenesis and switches the processes of surface erosion and/or sedimentation. These processes have an effect on the distribution of ancient settlements and can be the cause of the abandonment of cities. In the Lerma Valley, particularly in the Tres Mezquites area, surveys and extensive excavations have been conducted to estimate the nature and density of pre‐Hispanic settlements on the alluvial plain and in the piedmonts. Most of the archaeological structures are covered by dark clayey soils (Vertisols). This includes the PA3_El Pitayo site, where an accumulation of black earth has been detected on the floors and walls of a collapsed building. We have studied in detail the Vertisols and the black earth around the site to establish to what extent this dark earth is an in situ product of the soil‐forming factors, or if its accumulation is due to erosion/sedimentation processes, which could affect the occupation of the site, or the result of anthropic activity for leveling. The Vertisols and the dark earth are characterized by different means (physical, chemical, micromorphology, clay mineralogy, and radiocarbon dating). The results show that both the Vertisols and the black earth are very clayey, with angular blocky structures and slickensides (properties that are typical of vertic soils), and smectite as the main clay mineral. Besides smectite, under the microscope, a high amount of fresh volcanic glass is identified, suggesting that volcanism could be responsible for the abandonment of the study site. However, there are no known volcanic events related to the age of abandonment. As a consequence, we consider that landslides triggered by seismic activity/climatic events impacted the settlement.

Aachen-Heerlen annotated steel microstructure dataset

Studying steel microstructures yields important insights regarding its mechanical characteristics. Within steel, microstructures transform based on a multitude of factors including chemical composition, transformation temperatures, and cooling rates. Martensite-austenite (MA) islands in bainitic steel appear as blocky structures with abstract shapes that are difficult to identify and differentiate from other types of microstructures. In this regard, material science may benefit from machine learning models that are able to automatically and accurately detect these structures. However, the training process of the state-of-the-art machine learning models requires a large amount of high-quality data. In this dataset, we provide 1.705 scanning electron microscopy images along with a set of 8.909 expert-annotated polygons to describe the geometry of the MA islands that appear on the images. We envision that this dataset will be useful for material scientists to explore the relationship between the morphology of bainitic steel and mechanical characteristics. Moreover, computer vision researchers and practitioners may use this data for training state-of-the-art object segmentation models for abstract geometries such as MA islands.

Inversion of electromagnetic induction data using a novel wavelet-based and scale-dependent regularization term

SUMMARY The inversion of electromagnetic induction data to a conductivity profile is an ill-posed problem. Regularization improves the stability of the inversion and a smoothing constraint is typically used. However, the conductivity profiles are not always expected to be smooth. Here, we develop a new inversion scheme in which we transform the model to the wavelet space and impose a sparsity constraint. This sparsity constrained inversion scheme will minimize an objective function with a least-squares data misfit and a sparsity measure of the model in the wavelet domain. A model transform to the wavelet domain allows to investigate the temporal resolution (periodicities at different frequencies) and spatial resolution (location of the peaks) characteristics of the model, and penalizing small-scale coefficients effectively reduces the complexity of the model. The novel scale-dependent regularization term can be used to favour either blocky or smooth structures, as well as high-amplitude models in globally smooth structures in the inversion. Depending on the expected conductivity profile, a suitable wavelet basis function can be chosen. The scheme supports multiple types of regularization with the same algorithm and is thus flexible. Finally, we apply this new scheme on a frequency domain electromagnetic sounding data set, but the scheme could equally apply to any other 1-D geophysical method.

Automated extraction of structural beam lines and connections from point clouds of steel buildings

AbstractThis paper presents an alternative to segmentation of point clouds tailored specifically to large‐scale steel buildings. Typical segmentation approaches process the 3D point data directly and focus on large blocky structures such as concrete; these are not generalizable to smaller, more complex geometries found in steel elements. The method takes advantage of image processing techniques by utilizing 2D “slices” of the point cloud, rather than the original 3D point cloud. Centroids of targeted structural cross sections are extracted from these slices using 2D convolution as a template‐matching operation, and then projected back to 3D. From this, member centroidal axes are extracted using a custom linear region growing algorithm to create a 1D beam line model, including connections. Experimental results from scans of four prefabricated steel buildings indicate that the method is robust to variations in framing systems, clutter (e.g., obstructions, nonstructural elements), and point cloud sparsity.

Soil: Chemical characteristics of Vallanadu series in Tamiraparani river basin of southern Tamil Nadu, India

The soils of Vallanadu were characterized based on morphological, physico-chemical properties for land evaluation and classification. The soils were very shallow to deep, red to yellowish in colour, sandy loam to sandy clay in texture and had sub-angular blocky and angular blocky structures. The sand, silt and clay varied from 46.7 to 82.14%, 2.95 to 33.74% and 8.15 to 44.1% respectively. The soils were moderately acidic to moderately alkaline, non-saline, low to medium in organic carbon. The CEC varied from 4.5 to 16 Cmol(p+)kg-1 and dominated by Ca2+ >Mg2+>K+>Na+. The soils were low, medium, low to medium in available NPK respectively. Among the micronutrients, Fe and Mn were sufficient, Zn & Cu were deficient. The soils were classified as Typic Rhodustalf, Typic Haplustalf and Typic Haplustepts. The soils were evaluated as land capability sub-class of IVs, IVes and land irrigability sub-classes of 2s, 3s and 3st.

Structural evolution of β-iPP with different supermolecular structures during the simultaneous biaxial stretching process

Two different supermolecular structures of β-iPP cast films were used to investigate structural evolution during the simultaneous biaxial stretching process via small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. Based on the mechanical behaviors and porosity variations during the stretching process, it was found that the two samples had different structural evolution modes. During the initial stage of deformation, β-hedrites exhibited violent cavitation behavior in the center region of the hedrites by forming elliptical crazes and expanding, while β-spherulites were more inclined to fragment into blocky crystal structures, which was accompanied by the slippage of these structures. In the later stages of stretching, β-hedrites formed numerous dense regions around the elliptical crazes, which hindered microvoid formation and led to a poor pore size distribution. Conversely, β-spherulites generated abundant microfibrillar structures, and abundant microvoids were formed by directly separating the microfibrils, forming a membrane with a superior pore size distribution. The structural evolution of β-iPP with two different supermolecular structures during the simultaneous biaxial stretching process was studied. The two samples showed different structural evolution modes. β-hedrites exhibited violent cavitation behavior during the initial stage of deformation, but in the late stages of stretching β-hedrites formed numerous dense regions, which hindered microvoid formation and led to a poor pore size distribution. Conversely, β-spherulite generated abundant microfibrillar structures, and abundant microvoids were formed, forming a membrane with a superior pore size distribution.