Black Core Research Articles

Bloating zone of artificial lightweight aggregates in triaxial whiteware compositions using ME-DOE

This study examines the characteristics of manufactured aggregates by designing an experiment using Mixture Experiments Design of Experiments (ME-DOE) for triaxial whiteware compositions and proposes the optimal mixture for manufacturing artificial lightweight aggregates. The optimal mixture designed using ME-DOE was manufactured in a pilot-scale rotary kiln. The density and water absorption rate of the manufactured aggregates were measured, and the cross-section was observed. Additionally, Mercury Intrusion Porosimetry (MIP) and 3D-CT observation were conducted to observe the pores. The samples designed using the ME-DOE were classified into five types based on the internal microstructure, which had a high correlation with the physical properties of the aggregates. The matrix composition, excluding Fe2O3 and carbon in the area where the black core was created and bloated, was formed in the area of a typical triaxial whiteware mixture. Lightweight aggregates were manufactured at the Pilot Rotary Kiln using a 50:50 mixture of feldspar and ball clay, and the manufactured lightweight aggregates met ASTM C330 standards.

High-resolution integrated stratigraphy of Upper Ordovician to lower Silurian strata: applications to black shale drill cores in South China

High-resolution integrated stratigraphy of Upper Ordovician to lower Silurian strata: applications to black shale drill cores in South China

Evolution mechanism of Ti(C,N)-based cermet microstructure under microwave sintering

Experimental studies of microwave-sintered cermets were carried out at different sintering temperatures and holding times to investigate their microstructure evolution mechanism. Results of the study show that: (1) As sintering temperature increases, main microstructure evolution mechanisms of cermets are as follows: metal-phase melting, hard-phase skeleton filling of large pores in hard-phase skeletons, secondary rearrangement of the liquid phase (the liquid phase gradually fills the space between grains), and cooling down (precipitation–crystallization–reattachment); (2) As holding time increases, main microstructure evolution mechanisms of cermets are as follows: complete filling of large pores in the hard-phase skeleton, secondary rearrangement of the liquid phase, intense dissolution precipitation enhancing the formation of core-rim phase, and secondary homogeneous arrangement of the liquid phase. The special electromagnetic effects of microwave-sintered cermets and their influence on the sintering process were analyzed. It was found that both tip-discharge effect and hot-spot effect occurring during the microwave sintering process are conducive to the sintering process. The formation process of core-rim phase of cermets was also studied. Results show that: (1) Cermets form black core–white rim–grey rim structure via dissolution–precipitation and precipitation–crystallization phenomena; (2) Cermets form white core–grey rim structure through agglomeration of small particles, dissolution–precipitation, and precipitation–crystallization phenomena.

Photovoltaic modules fault detection, power output, and parameter estimation: A deep learning approach based on electroluminescence images

Accurately detecting faults in photovoltaic modules/cells and estimating their effective power output and parameters of the equivalent circuit representation of photovoltaic modules is becoming increasingly critical for both the reliability of associated systems and the efficiency of electricity production from renewable energy sources. Existing studies often work with datasets containing photovoltaic cells that exhibit one fault at a time, leading to the classification of photovoltaic cells with multiple faults as “mixed” faults. Moreover, factors such as cell alignment and specific fault types, collectively called “cell level features”, are not considered in current studies estimating the power output of a photovoltaic module. Therefore, this paper focuses on a comprehensive deep-learning pipeline to separately detect three types of faults in photovoltaic modules/cells using electroluminescence images. Furthermore, it addresses the estimation of the output power of photovoltaic modules and the series resistance of their equivalent circuit, considering the cell-level characteristics extracted from the electroluminescence images. The proposed model demonstrates its ability to detect “black core”, “crack”, and “edge” faults with global accuracies of 0.93, 0.868, and 0.95, respectively. Furthermore, the proposed model estimates the power output of photovoltaic modules with a normalized mean absolute error of 0.03547 and a normalized root mean squared error of 0.04892. This outperforms the base model that relies solely on non-pre-processed detected faults and significantly larger models adept at extracting features from the electroluminescence images. Moreover, the VGG16-based model estimates the series resistance in the equivalent circuit representation of photovoltaic modules with a normalized mean absolute error of 0.04472 and a normalized root mean squared error of 0.0622.

Effect of Si content on microstructure and properties of Ti(C, N)-based cermet

The effects of Si additions (0, 0.5 wt%, 1 wt%, 1.5 wt%) on the microstructure, mechanical properties and oxidation resistance of Ti(C, N)-based cermets were investigated. The results showed that Si additions would combine with Mo, which leaded to the formation of MoSi2. Even though the ceramic black core phase was refined, the increase in Si content decreased the wettability between the binder and hard phases. The bending strength of the cermet grew and subsequently declined as the Si content increased, while the hardness did not change much. The most optimized comprehensive properties of the cermets were achieved with Si addition of 1 wt%, The bending strength, hardness and fracture toughness was 2133.7 MPa, 89.6 HRA and 12.21 MPa m1/2 respectively. In another side, cermets with 1 wt% Si addition had lower oxidized weight increase and a thinner oxide film than that without Si. A denser oxidation film composed of SiO2 and NiTiO3 was generated during the oxidation process on the surface of the cermets with Si addition, and this would prevent O elements from diffusion into the cermets, thus the oxidation resistance was enhanced.

Evolution of refractory black carbon mixing state in an urban environment

The size distribution and hygroscopicity of the refractory black carbon (rBC) aerosol are critical properties for understanding its impact on human health, the extent to which the particles disperse through the atmosphere, and the effect that the particles have on clouds and the climate system. The hygroscopicity of black carbon is primarily controlled by the degree to which the black carbon cores are coated with other compounds. Here we show new measurements of rBC obtained from a single particle soot photometer at an urban location in Houston, TX, USA during the Department of Energy TRacking Aerosol Convection Interactions ExpeRiment (TRACER) campaign. We classified rBC particles into uncoated, thinly coated and thickly coated, where the latter is defined as the optical coating thickness exceeding 10 nm. To understand how aerosol aging and the prevailing winds interact to affect rBC coatings, a slice of the size distribution with rBC core diameter 143–166 nm is considered. For this slice, the average coating thickness of thickly coated particles was 29 ± 8 nm. The rBC number concentration, the fraction of thinly and thickly coated particles, and the average coating thickness strongly vary with the wind direction. We found that onshore flows are associated with lower number concentrations, more thinly coated particles, and thinner coatings when compared to offshore flows. Diurnal profiles show that the fraction of coated particles increases during daytime, likely due to photochemical aging. The estimated fraction of rBC particles that may activate into cloud droplets at 0.1% and 1% water supersaturation was generally ∼0.6% and ∼9%, respectively. This suggests that substantial further aging is needed to precondition the majority of rBC particles for incorporation into cloud droplets.

Tourmaline as a petrogenetic indicator highlighted in a multicoloured crystal from the gem deposit of Mavuco, Alto Ligoña pegmatite district, NE Mozambique

Abstract A rounded fragment of a multicoloured tourmaline crystal (2.5 cm diameter), collected from the secondary gem deposit of Mavuco, Alto Ligoña pegmatite district, Mozambique, has been investigated using a multi-analytical approach, with the objective of reconstructing its growth history. The sample represents a core-to-rim section, perpendicular to the c axis, of a crystal characterised by a variety of colours. These change from a black core to an intermediate zone with a series of colours, yellow, blue–green and purple, to a final dark-green prismatic overgrowth. These changes are the result of a wide variation in Fe, Mn, Ti and Cu concentrations and their redox state. The black core is characterised by enrichment in Fe and Mn, with iron present in its divalent state. The yellow zone shows a progressive depletion in Fe and its colouration is caused by Mn2+ and Mn2+-Ti4+ IVCT interactions. The progressive decrease in Mn coupled with the absence of Ti, and the lack of Fe, implies that Cu2+ acts as the only chromophore in the pale blue–green zone. The dominant colour-causing agent of the purplish zone is Mn3+, denoting a change in redox environment; however, even though the amount of Cu remains significant, its chromophore effect is obscured by Mn3+. The dark-green prismatic overgrowth, characterised by a sharp increase in Fe, Mn and also Ca, is interpreted as a late-stage partial re-opening of the geochemical system. This occurrence could potentially be related to mechanical instability of the cavity in which the crystal grew.

Exploring the feasibility of utilizing high plastic clays as an alternative material to bentonite clay in the production of ceramic tile: Advancing towards efficient life cycle cost

The environmental challenges and high cost of raw materials (i.e., bentonite clays) for the production of ceramic tiles raise concerns for the ceramic industry to look for alternative materials. Therefore, the current research aimed at exploring the possibility of using high plastic clays as a replacement for Bentonite clay in the manufacturing of ceramic tiles. Two different types of high plastic clay in different proportions (i.e. 0–5 %) were used in the preparation of ceramic tiles. A comprehensive material characterization, shrinkage, visual index, flexural strength, water absorption, and microstructural investigation was carried out. The results revealed that the incorporation of plastic clays RC1 from 1 % to 5 % showed a decrease in the flexural strength of ceramic tiles as compared to that of ceramic tiles with bentonite clay. The water absorption of ceramic tiles using RC1 increased with the incorporation of high plastic clays for high plastic clays. However, specimens with all replacements of bentonite clay with high plastic clays showed flexural strength greater than the minimum specified limit of ISO 10545-4. Moreover, it was observed that the replacement of bentonite clay with high plastic clays exhibited higher shrinkage. Further, the visual index of all the specimens did not show any sign of the presence of black core in the ceramic tiles incorporating high plastic clays. The life cycle assessment (LCA) was carried out for the possible utilization of high plastic clays in place of bentonite clay to produce ceramic tiles. The results showed that less than 5 % high plastic clay can effectively be used for manufacturing ceramic tiles leading to economical and sustainable construction products. Hence, it can be concluded that the high plastic clays can be utilized as an alternative to bentonite clay material for manufacturing sustainable ceramic tile leading to sustainable finishes in construction.

Minimalisasi Defect Produk Granite Tile Pada Proses Sorting & Polishing Dengan Pendekatan Root Cause Analysis (RCA) (Studi Kasus di PT. Niro Ceramic Nasional Indonesia, Bogor–Jawa Barat )

Competition in the industry makes manufacturing companies do continuous improvement of production in order to achieve good quality. PT. XYZ is a company engaged in the manufacturing industries that produce granite tile. The problems that often arise on the production floor, especially in the process of sorting and polishing that is, the high defect products produced in the process. The purpose of this study is to minimize damage to the product on the S & P, Useful and finished product quality improvement plans. To support solving this problem, researchers used a method approach Root Cause Analysis (RCA). In the histogram obtained from the check sheets, Pareto diagrams visible damage in the S & P damage type of disability the most dominant is the Crack (57%), followed Thick (18%), Glaze Drop (11%), Black Coring (8%), and the last is the Scraper Defect (6%). From the research, a result that most of the damage is Crack. Factors causing these defects are the factors that cause deviations quality raw materials such factors, factors working methods irregularities in the implementation of the work, a factor that is less engine preventive maintenance, factor of fewer operators do not obey the standard factory operations. From the productivity results in the S & P, generate some suggestion in terms of minimizing the product is defective is implementing kaizen. Keywords: Root Cause Analysis (RCA), Application of Process Improvement, Kaizen, 5S, Granite Tile.

Emergence of species scale black hole horizons

The scale at which quantum gravity becomes manifest, the species scale Λs, has recently been argued to take values parametrically lower than the Planck scale. We use black holes of vanishing horizon area (small black holes) in effective field theories coupled to quantum gravity to shed light on how the three different physical manifestations of the species scale Λs relate to each other. (i) Near the small black hole core, a scalar field runs to infinite distance in moduli space, a regime in which the Swampland Distance Conjecture predicts a tower of exponentially light states, which lower Λs. (ii) We integrate out modes in the tower and generate via Emergence a set of higher derivative corrections, showing that Λs is the scale at which such terms become relevant. (iii) Finally, higher derivative terms modify the black hole solution and grant it a non-zero, species scale sized stretched horizon of radius Λs−1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\Lambda}_s^{-1} $$\\end{document}, showcasing the species scale as the size of the smallest possible black hole describable in the effective theory.We present explicit 4d examples of small black holes in 4d N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{N} $$\\end{document} = 2 supergravity, and the 10d example of type IIA D0-branes. The emergence of the species scale horizon for D0-branes requires a non-trivial interplay of different 8-derivative terms in type IIA and M-theory, providing a highly non-trivial check of our unified description of the different phenomena associated to the species scale.

Ceramic Firing Temperature Trajectory Monitoring System on IoT-Based Gas Furnace

This study introduces a novel system where a conventional ceramic furnace is upgraded with IoT capabilities, specifically utilizing NodeMCU and a thermocouple sensor. The integrated system enables real-time temperature monitoring, facilitating the correction of firing trajectory errors in the ceramic firing process. The sensors reading minimizes errors by detecting temperature changes with a maximum deviation of -2.5 °C and a minimum deviation of -1 °C. The average error ranges from 1.81% to 3.79%. The collected data is seamlessly transmitted to Google Spreadsheet for online monitoring. This comprehensive solution not only minimizes recording errors but also ensures the quality of final ceramic products by preventing issues such as cracks, breaks, black cores, and non-uniform sizes. The incorporation of NodeMCU, thermocouple sensors, and online monitoring represents a significant technological leap in optimizing ceramic firing processes for heightened precision and efficiency.

ANALYSIS AND RESTORATION OF GRECO-ROMAN POTTERY IN EGYPT

The research aims to identify features of the industry and assess the pottery damage through various examinations and analyses, such as examination by polarised microscope (PLM), examination by Scanning Electron Microscope with Energy Dispersive X-ray unit "SEM-EDX", analysis by X-ray diffraction powder XRD, and thermal analysis TGA. Archaeometric features of archaeological pottery were identified. The used clay is Nile Clay; the additives are sand, limestone powder, pottery powder (grog), and straw. The moulding technique is the hand and potter wheel technique. The surface treatment is a red wash and slip layer. The burning atmosphere is oxidising for the first and second pottery pieces and reducing for the third and fourth pottery pieces. The burning temperature is about 816°C for the first sample, 887°C for the second sample, 706°C for the third sample, and 651°C for the fourth sample. The texture is medium to coarse fabric for the first sample; the second sample fabric is fine; and the third and fourth samples have a coarse texture. The research proved that the pottery objects suffer from some different damage aspects such as fracture, loss of some parts, lack of strength, weakness, cracking, soil sediments, soot spots and black core, and salt crystallisation (chloride, sulphate, carbonate, and phosphate salts). The research proved the use of a mixture of distilled water, acetone, and ethyl alcohol at a ratio of 1:1:1, respectively, for removing clay soil deposits. EDTA is used to remove lime deposits. Nano-silica at a concentration of 0.5% is used to strengthen archaeological pottery by spraying. Paralloid B 82 dissolved in trichloroethylene at a concentration of 50% in assembling the pottery sherds; it is preferable to display it in the museum at a temperature of 20°C and a relative humidity of 55:60%.

Influence of WC addition on mechanical properties of (HfNbTaZrTiMo)C‐Co cermet

Abstract(HfNbTaZrTiMo)C‐Co high entropy carbide cermet was fabricated by conventional vacuum sintering. The effect of WC addition on the mechanical properties of cermets was also investigated. For cermets without WC addition, with the extension of sintering time, the hardness of cermets first rose and then fell, while the fracture toughness showed a decreasing trend. The increase in sintering temperature led to a decline in hardness and an enhancement of fracture toughness. The (HfNbTaZrTiMo)C‐15 wt. % Co cermet sintered at 1450°C for 2 h had the best comprehensive properties, with the hardness and fracture toughness of 16.36 ± 0.17 GPa and 7.19 MPa·m1/2, respectively. After adding WC, there was a typical black core (undissolved (HfNbTaZrTiMo)C phase)‐gray rim (seven‐component (HfNbTaZrTiMoW)C solid solutions) structure in the cermets. Meanwhile, Mo diffused into WC to form (Mo, W)C solid solutions. The formations of (HfTaZrNbMoTiW)C and (Mo, W)C solid solutions resulted in an improvement in hardness. In addition, since the addition of WC enhanced the wettability between carbides phase and Co phase, the comprehensive properties of cermets were improved. The hardness and fracture toughness of the (HfNbTaZrTiMo)C‐42.5 wt. % WC‐15 wt.% Co cermet sintered at 1450°C for 2 h were 17.42 ± 0.06 GPa and 8.22 MPa·m1/2, respectively.

Black hole entropy contributions from Euclidean cores

The entropy of a Schwarzschild black hole, as computed via the semiclassical Euclidean path integral in a stationary phase approximation, is determined not by the on-shell value of the action (which vanishes), but by the Gibbons–Hawking–York boundary term evaluated on a suitable hypersurface, which can be chosen arbitrarily far away from the horizon. For this reason, the black hole singularity seemingly has no influence on the Bekenstein–Hawking area law. In this paper, we estimate how a regular black hole core, deep inside a Euclidean black hole of mass [Formula: see text] and generated via a UV regulator length scale [Formula: see text], affects the black hole entropy. The contributions are suppressed by factors of [Formula: see text]; demanding exact agreement with the area law as well as a self-consistent first law of black hole thermodynamics at all orders, however, demands that these contributions vanish identically via uniformly bounded curvature. This links the limiting curvature hypothesis to black hole thermodynamics.

Spark plasma sintering of Ti(C, N)-based cermet tool material doped with refractory rare metal carbides (TaC/NbC/VC): Core-rim structure, grains and mechanical properties

The secondary carbides have great impacts on microstructure and mechanical properties of Ti(C, N)-based cermets. In the study, Ti(C, N)-based cermets doped with different refractory rare metal carbides TaC/NbC/VC which was used for cutting tools were prepared by spark plasma sintering. The effects of TaC, NbC and VC on core-rim structure, grain size and mechanical properties of the cermets were studied. TaC/NbC/VC promotes the growth of solid solution phase, reduces the size of black core, increases the intergranular fracture and decreases the cleavage fracture. The solid solution effect and grain refinement effect of VC are stronger than that of NbC, while NbC is superior to TaC. Adding appropriate TaC/NbC/VC can improve the mechanical properties. The best comprehensive mechanical properties of Ti(C, N)-based cermets are achieved with the addition of 3 wt% VC, with a relative density of 99.5%, Vickers hardness of 18.4 ± 0.3GPa, fracture toughness of 10.7 ± 1.3 MPa·m1/2, and flexural strength of 947.4 ± 12.6 MPa.

Waste toner–derived carbon dots for bioimaging and photodynamic therapy

Printer toner, which accounts for a large fraction of electrical and electronic wastes, poses serious environmental and health risks but cannot be efficiently recycled because of its high chemical durability and complexity. Specifically, only 20–30% of waste toner is recycled, while much of the remainder ends up in landfills and thus contributes to air/soil pollution and respiratory disease development. Herein, we report the one-pot hydrothermal processing of waste toner into well-dispersed and uniform-sized carbon dots featuring abundant surface defects (e.g., radicals and dangling bonds), strongly interacting with UV (200–400 nm) light, and exhibiting intense photoluminescence in both UV (300 nm) and visible (400–500 nm) ranges. In particular, ethanolamine is used to chemically disintegrate the carbon black cores of toner particles into nanoparticles and simultaneously passivate the nanoparticle surface. According to the results of time-correlated single photon counting spectroscopy measurements, UV- and visible-region photoluminescence originates from amorphous carbon structures in the core and oxygen/nitrogen-containing functional groups on the surface, respectively. Finally, in view of their excellent visible-region optical properties and the ability to generate reactive oxygen species under laser irradiation, the waste toner–derived carbon dots are demonstrated to be promising agents for bioimaging and photodynamic therapy, respectively.

Effect of La2O3 addition on microstructure and mechanical properties of TiC-based cermets

Rare earth (RE) oxides are typically used as dopants to improve the toughness of cermet materials. However, their effect on the cermet microstructure remains to be clarified. Towards this end, we used a vacuum sintering method to prepare the TiC-based cermets with different La2O3 contents (0.3 wt.% and 0.5 wt.%) and studied the cermet microstructures evolution by coupling experimental approaches and thermodynamic calculations. With the addition of La2O3, the ceramic phase in TiC-based cermets formed the black core-grey rim structure, where the undissolved La2O3 appeared at the edges of grey rims. In addition, an unanticipated solid-solution of La in the ceramic phase was observed, which helped to refine the particle size of the black cores and reduce the porosity of cermets. Correspondingly, the toughness and density were increased as a result of the well-developed grey rims around the black cores and the improved wettability between the ceramic and metallic phases. Thermodynamic calculations further unveiled that the solid-solution of La was inclined to occur in the ceramic phase rather than the metallic phase, while the incorporation of a trace amount of La could enlarge the temperature range of liquid-phase sintering, facilitating the formation of grey rims following an iterative dissolution and precipitation process. Thus, the current work has described the effect of La on the microstructure and mechanical properties of TiC-based cermets, which may help guide the future developments of RE-containing cermets.

Avoidance of Singularity during the Gravitational Collapse with String T-Duality Effects

In this paper, we explore the gravitational collapse of matter (dust) under the effect of zero-point length l0. During the gravitational collapse, we neglect the backreaction effect of pre-Hawking radiation (in the sense that it is a small effect and cannot prevent the formation of an apparent horizon), then we recast the internal metric of a collapsing star as a closed FRW universe for any spherically symmetric case and, finally, we obtain the minimal value for the scale factor, meaning that the particles never hit the singularity. We argue that the object emerging at the end of the gravitational collapse can be interpreted as Planck stars (black hole core) hidden inside the event horizon of the black hole, with a radius proportional to (GMl02/c2)1/3. Quite interestingly, we found the same result for the radius of the Planck star using a free-falling observer point of view. In addition, we point out a correspondence between the modified Friedmann’s equations in loop quantum gravity and the modified Friedmann’s equation in string T-duality. In the end, we discuss two possibilities regarding the final stage of the black hole. The first possibility is that we end up with Planck-size black hole remnants. The second possibility is that the inner core can be unstable and, due to the quantum tunneling effect, the spacetime can undergo a black-hole-to-white-hole transition (a bouncing Planck star).

Cutaneous Anthrax After a Cat Scratch: A Case Report

Despite a global decline, Central Asia and Africa remain vulnerable to anthrax. Anthrax is usually caused by bacteria that enter the body through a wound from slaughtering sick animals. 95% of anthrax cases are skin-related. After 1 to 7 days, the spores in skin abrasion become vegetative. We present a 42-year-old woman with a cat scratch history who had small itchy blisters and swelling around a painless skin ulcer with a black core, low-grade fever, and hypotension. She had anemia, hypotension, and bilateral lower limb ulcers. Wound culture showed gram-positive bacilli compatible with B. anthracis. Blood transfusion, Ciprofloxacin 200mg/100ml twice daily, Meropenem 1g three times daily, and Clindamycin 600mg three times daily was given. Her amputated gangrene-infected finger helped her recover. Early diagnosis, antibiotic therapy, and preventive measures like immunization help control epidemics. This sporadic case of cutaneous anthrax alerts physicians.

Fly ash-based frit as a sintering aid for ceramic body

Coal fly ash is characterized by high silica and alumina contents, making it suitable as a raw material for alumosilicate ceramics. However, direct use of fly ash reveals obstacles such as high porosity, black core, cracking, and swelling. This work synthesized frit by melting a mixture of fly ash, quartz, limestone, and soda. TG-DSC analysis showed that the glass transition point of the frit occurs at approximately 600 degrees Celsius. Ceramic bodies from raw mixes containing various frit amounts were prepared and characterized. The results showed that with 4% being frit, the firing temperature could be reduced by 30 degrees Celsius, along with decreased water absorption and increased flexural strength. Besides, no swelling, cracks, or black cores occur. These observations indicate that fly ash-based frit is viable a sintering aid in ceramic production.