Visible Layer Research Articles

City as palimpsest: Visible and invisible memory of “Students Square” in Belgrade

The New heritage paradigm is changing the way in which the past is valued and affirming the pluralised and user-oriented presentation of visible and invisible urban memory. The assumption of the paper is that reading the city as a palimpsest can be the basis for a democratic heritage presentation and a multivocal and multitemporal understanding of the past by unveiling the visible and invisible layers of urban memory. The question arises to what extent traditional formats of heritage presentation in public spaces can respond to these demands. This paper aims to explain the concept and method of reading the city as a palimpsest and to demonstrate its application in the case of Students Square in Belgrade to discover and unveil invisible urban memory, while critically reviewing the traditional presentation formats and their ability to adequately present it in public spaces. The results of the research confirm the potential of the palimpsest method and point to a selective approach and physical limitations of traditional formats to present the complexity of urban memory in urban public spaces.

Применение вибрационной галтовки при подготовке поверхностей деталей из алюминиево-магниевых сплавов в условиях мелкосерийного и серийного производства

The tumbling process is considered from the point of view of its technology on the basis of the experimental data obtained in the production workshops of JSC "TsNIRTI im. Academician A.I. Berg". The types of finishing equipment are analyzed taking into account the efficiency of the technological operation of finishing, depending on the material used and processing modes. The optimal modes are determined depending on the processing of parts made of aluminum alloys of the Al–Mg system, taking into account the requirements of regulatory documents [2]. The surface roughness of the base metal should be no more than Ra 10 (Rz 40) – for protective coatings and Ra 1.25 (Rz 6.3) – for solid and electrically insulating anodic oxide coatings. The surface of the parts after machining should be free of a visible layer of lubricant or emulsion, metal chips, burrs, dust and corrosion products without the introduction of particles of foreign material [2].

Greenery as an Element of Imageability in Window Views

A window view affects a person’s well-being and comfort. The effect of visual contact with nature on people depends on the quality of the outside scenery, which in turn depends on parameters such as the number of visible layers, the distance to visual elements and environmental information (content) in the window view. Many studies have concluded that views of nature are preferable, while in urban environments a high-quality window view should include greenery. In our study, a survey was conducted among two groups of students at the Faculty of Architecture, University of Ljubljana, to find out how the respondents perceived urban imageability in a window view. Using the example of five neighborhoods in Ljubljana (Slovenia), which have different urban planning and design concepts and greeneries, we investigated whether respondents perceived the presence of greenery as an important element of visual comfort. They ranked the quality of window views using eight indicators. The analysis of the ranking of the answers showed that the responses were similar for the two survey approaches (with single-selection and with multiple-selection techniques), except for the perception of surface texture. This indicates a common understanding of the role of greenery and an ambiguity in the perception of what is meant by the term ‘texture’.

Study of Microstructure and Properties of Aluminum/Steel Inertia Radial Friction Welding

In this paper, 6061-T6 aluminum alloy and 30CrMnSiA steel are bonded by inertia radial friction welding (IRFW). The formation mechanism of the aluminum/steel friction welded joints and the effect of the welding parameters on the mechanical properties are investigated through the microstructure, microzone composition, and mechanical property analysis. The results show that no visible intermetallic compound layers (IMCs) are detected on the aluminum/steel welding interface, which may be due to Si element aggregating in the welding interface and then forming a Al−Fe−Si phase, preventing the formation and growth of an Al−Fe IMCs. Eventually, a micron ultrathin interface reaction layer composed of Al0.7Fe3Si0.3, FeAl, and Fe3Al phases is formed at the aluminum/steel welding interface. The maximum average shear strength of the joint is 176 MPa. The shear fracture is a typical ductile fracture. Properly reducing the friction speed and increasing the upsetting pressure can improve the bonding strength of aluminum/steel joints.

Charge-Discharge Properties of Sputtered Mg Anode in Flexible All-Solid-State Mg-Ion Batteries.

In this study, a sputtered Mg film was fabricated as an anode, a natural magnesium silicate mineral was used as electrolyte, and an all-solid-state Mg battery with a carbon black electrode was assembled; subsequently, the battery's electrochemical characteristics and charge-discharge mechanism were evaluated. Because the abundant interlayer water in the magnesium silicate mineral structure allowed for cations channel to form, the battery exhibited considerable ionic conductivity at room temperature. The magnesium silicate mineral was fabricated as a flexible cloth membrane solid-state electrolyte to improve its adhesion to the electrode surface and, consequently, enhance battery performance. During high-voltage charging, a visible blocking layer structure was formed on the surface of the Mg electrode. The formation of the blocking layer considerably increased the interfacial resistance of the battery, which was detrimental to the insertion and extraction of the Mg ions on the electrode surface and reduced the capacity of the solid-state battery. Thus, the solid-state Mg battery exhibited acceptable capacity and stability and the potential for application in energy storage systems.

송국리형 주거지 내부 흑색토층의 형성과정에 대한 일고찰 -토양 미세형태분석과 규소체분석의 통합적 접근-

The process of spatial utilization and waste disposal practices evident in Songguk-ri type houses is among the most fascinating research topics of the Bronze Age on the Korean peninsula, and in particular, the presence of internal black-coloured deposit layers therein has drawn much scholarly attention. The 24th and 25th excavation surveys of the Songguk-ri site employed methodological approaches embraced in environmental archaeology including phytolith and soil micromorphological analyses. The surveys investigated Houses (Nos. 98, 100 & 107) where internal black-coloured deposit layers were identified. Based upon soil micromorphological analysis, it can be suggested that these inner black-coloured deposit layers appear to be formed by accumulation of carbonized materials, thus insinuating carbonization process occurred within relatively close proximities. It may also be indicative of deposition of burned and collapsed superstructures, including roofs and walls. Meanwhile, the phytolith analysis of House No. 100 suggests that a large amount of phytoliths of rice and foxtail millet were located in the upper sedimentary soil and middle black-coloured deposit layers. Crops, grasses, and lowland soils (e.g., rice paddy) containing sponge spiculates were used as building materials for structures such as walls. In addition, distribution patterns of the houses and storage pits containing visible black-coloured deposit layers, which often neighbor each other, reveal that the combusted materials flowed into the houses and nearby pits. Taken together, some houses following the discard thereof, were likely to have had their remaining structures burned when recycling was difficult after the dismantling and removal of major construction materials such as pillars. Therefore, it is estimated that the black-coloured layer was deposited inside the house after the sedimentary deposits were initially accumulated and burned to some extent in the process. Collaborative research such as this article help to reinforce assumptions and expand the interpretive potential and thus should be further encouraged.

Same source profiling of 3D printed firearms using deposition striae: a discussion

ABSTRACT 3D printer technologies using polymer and polymer/hybrid filament materials are being used to construct illicit firearm components with strength and longevity using low cost fused deposition modelling (FDM) printers. This preliminary discussion poses the question, can deposition x, y, and z-axis layers created by additive manufacturing (AM) technology produce visible layering and surface characteristics upon a 3D FDM manufactured object which have the potential for examination to extract characteristics suitable for forensic comparison? The examination and analysis of deposition layers (striae) based upon the mechanical variation of 3D printers has not been fully investigated and the illegal adaption of 3D print FDM technology for the prolific manufacture of firearm components demands further study. A summation of possible examination techniques and suggested directions for further research may assist in developing a better forensic response for the examination of 3D FDM printed polymer and polymer/hybrid components.

The dating and correlation of an eastern Mediterranean lake sediment sequence: a 46–4 ka tephrostratigraphy for Ioannina (NW Greece)

ABSTRACTTerrestrial archives from the Mediterranean have been crucial to expanding our understanding of past environmental variability on a range of timescales. Dating Quaternary sequences in the Mediterranean is, however, often challenging, and age models often have large chronological uncertainties. Tephra deposits can provide crucial age control for detailed environmental reconstructions on sub‐centennial timescales. Here, tephra analysis is undertaken for the first time on a sediment core (I‐08) from Lake Ioannina, northwest Greece, for the interval spanning 46–4 ka bp. Detailed visible and ‘crypto‐’ tephra analysis identifies deposits associated with explosive volcanism at Italian volcanic sources, including Campi Flegrei, Pantelleria, and the Aeolian Islands. We identify two visible tephra layers, the Campanian Ignimbrite (CI/Y‐5; ca. 39.8 ka bp) and Pantelleria Green Tuff (PGT/Y‐6; ca. 45.7 ka), as well as the Holocene Vallone del Gabellotto cryptotephra marker (VG/E‐1; ca. 8.3 ka bp). Evidence for repeated remobilisation and redeposition of CI tephra material is outlined, and the potential mechanisms and effects of sediment reworking in lake environments are examined. Bayesian modelling, which incorporates the new tephra ages with earlier radiocarbon dates, extends the I‐08 core chronology back to ca. 46 ka bp, facilitating direct correlation of the Ioannina sequence to others in the Mediterranean region.

Whole tomato juice produced by a novel industrial-scale microfluidizer: Effect on physical properties and in vitro lycopene bioaccessibility

Whole tomato juice (WTJ) was prepared using a novel “industrial-scale microfluidizer system” (ISMS). The impacts of ISMS processing pressure (0–120 MPa) on the physicochemical properties and bioaccessibility of tomato juice were investigated. Increasing the processing pressure reduced the mean particle diameter (D[4,3]) of the tomato juice from 151 to 30 μm, which was mainly attributed to degradation of the tomato plant cell structures by the strong disruptive forces generated by microfluidizer. Pulp sedimentation rate, precipitation weight ratio, and turbidity measurements showed that the physical stability of the tomato juice increased with increasing pressure. Indeed, ISMS-treated tomato juice remained stable for 28 days without evidence of visible layering. The lycopene concentration in the tomato juice increased from 25.0 to 28.2 μg/mL and the lycopene bioaccessibility increased from 9.0% to 14.1% after ISMS treatment. These results suggest that ISMS can improve the physical stability and nutritive value of commercial tomato juice products.

The mineralization and early diagenesis of deep-sea coral Madrepora oculata

The skeletons of aragonitic corals carry essential information about oceanic environmental changes in the past. However, coral-based geochemical proxies are sensitive to vital effect and post-depositional diagenetic processes, which have not been well understood for deep-sea corals. In this study, we have investigated the mineralization and early diagenetic process of the dendroid stem of a dead deep-sea scleractinian coral sample (Madrepora oculata) collected by Remote Operated Vehicle (ROV) from a seamount in the Caroline Ridge, western Pacific. Despite being only ~270 years old, as dated by the U-series disequilibrium method, this sample already has extensive diagenesis including a visible chalky layer. The outermost chalky layer and the adjacent pristine skeleton of the sample were characterized by multiple mineralogical (SEM, XRD, EBSD, Raman Spectroscopy) and geochemical (ICP-OES, LA-ICP-MS, IR-MS, MC-ICP-MS) techniques. Skeletal stable C and O isotopes display strong linearity, with a trend pointing toward the theoretical isotopic composition of inorganically-precipitated aragonite from local seawater. This observation suggests that the epithecal mineralization of M. oculata is far from equilibrium with seawater and can be quantitatively explained by bio-mineralization models developed for solitary scleractinian corals. We further show that chalking of the outer layer, a common feature in sub-fossilized deep-sea corals, is caused by microbial-driven boring and μm-scale dissolution voids at an average rate of 3.5 μmol/cm2/y (scaled to the skeleton surface) without notable secondary infillings or mineralogical alternations. The higher average δ13C and δ18O of the chalky part than the pristine part might be due to the preferential dissolution of carbonate relatively depleted in 13C and 18O during alteration, and/or reduced isotope fractionation from seawater during coral mineralization of the outer layer. The chalky layer shows significantly higher Mn/Ca and Th/Ca ratios than the pristine part, characterized by Th/Mn ratios similar to that of the dissolved component of local seawater. Our study suggests that the incorporation of external Th into the coral skeleton is most likely associated with organic binding rather than detrital contamination, secondary carbonate mineral formation, adsorption onto surfaces of chalky aragonite or ferromanganese oxides, with important implications for coral U-series geochronology.

How reliable is µXRF core scanning at detecting tephra layers in sedimentary records? A case study using the Lake Suigetsu archive (central Japan)

AbstractHere, we evaluate the ability of micro X‐ray fluorescence (µXRF) core scanning to identify non‐visible volcanic ash (cryptotephra) layers in sedimentary records. Its suitability is assessed using the annually resolved lacustrine sediments of Lake Suigetsu (Japan) for which there is high‐resolution ITRAX µXRF core scanning data, and a detailed crypto‐tephrostratigraphy (formerly established via density separation techniques). The studied core sections contain 10 visible and 30 cryptotephra markers that span a range of glass concentrations (from 1000 to >20 000 shards per gram of dried sediment) and compositions (basalts, trachy‐andesites, phonolites, trachytes and rhyolites), thus providing an ideal case study. The ITRAX core scanner produced recognisable µXRF elemental responses for the visible ash layers, including those just 1 mm thick. However, just 10% of the cryptotephra layers could be unequivocally identified. Although this study demonstrates that µXRF core scanning should not be used as an independent method within a similar geological setting, we show it can provide a powerful tool alongside traditional techniques. Where detected, µXRF profiles can verify and refine cryptotephra positions (here to a sub‐millimetre resolution), and help establish reworking signatures. These insights create possibilities for ultra‐precise synchronisation of records, improved chronological modelling and help generate more complete eruption histories.

Simulating product-packaging conditions under environmental stresses in a food supply chain cyber-physical twin

Food supply chains (FSCs) enable safe, effective, and sustainable food distribution, linking farm to table. They involve multiple sources and destinations, a broad set of actors and handling modes, variable and unpredictable environmental conditions, potentially decaying food and packaging, affecting quality and consumer satisfaction. New methodologies, approaches, and ready-to-practice solutions to improve the FSC capacity to maintain the food quality and the packaging properties at the final consumer are expected and missing. To address such aspects simultaneously, this paper proposes a novel framework, using simulation, to study food product and packaging conditions under environmental stresses throughout the FSC. The framework includes five layers of study, i.e., the environmental layer, the FSC layer, the visibility layer, the simulation layer, and the functional layer, linking the field, i.e. the operative physical environment, to a simulation environment, based on a fully equipped and closed-loop controlled physical twin made of a climate-controlled chamber. The cyber-physical twin description is improved by reviewing a collection of case studies we used over the years to validate the framework and explore the functionalities of the physical twin. Case studies deal with different food products and packaging alternatives, demonstrating the flexibility of the proposed framework and physical twin to support the analysis and decision-making in FSC improvement.

A novel approach for designing efficient broadband photodetectors expanding from deep ultraviolet to near infrared

Broadband photodetection (PD) covering the deep ultraviolet to near-infrared (200–1000 nm) range is significant and desirable for various optoelectronic designs. Herein, we employ ultraviolet (UV) luminescent concentrators (LC), iodine-based perovskite quantum dots (PQDs), and organic bulk heterojunction (BHJ) as the UV, visible, and near-infrared (NIR) photosensitive layers, respectively, to construct a broadband heterojunction PD. Firstly, experimental and theoretical results reveal that optoelectronic properties and stability of CsPbI3 PQDs are significantly improved through Er3+ doping, owing to the reduced defect density, improved charge mobility, increased formation energy, tolerance factor, etc. The narrow bandgap of CsPbI3:Er3+ PQDs serves as a visible photosensitive layer of PD. Secondly, considering the matchable energy bandgap, the BHJ (BTP-4Cl: PBDB-TF) is selected as to NIR absorption layer to fabricate the hybrid structure with CsPbI3:Er3+ PQDs. Thirdly, UV LC converts the UV light (200–400 nm) to visible light (400–700 nm), which is further absorbed by CsPbI3:Er3+ PQDs. In contrast with other perovskites PDs and commercial Si PDs, our PD presents a relatively wide response range and high detectivity especially in UV and NIR regions (two orders of magnitude increase that of commercial Si PDs). Furthermore, the PD also demonstrates significantly enhanced air- and UV- stability, and the photocurrent of the device maintains 81.5% of the original one after 5000 cycles. This work highlights a new attempt for designing broadband PDs, which has application potential in optoelectronic devices.

Biserial targeted feature projection based radial kernel regressive deep belief neural learning for covid-19 prediction.

Coronavirus disease 2019 (COVID-19) is a highly infectious viral disease caused by the novel SARS-CoV-2 virus. Different prediction techniques have been developed to predict the coronavirus disease’s existence in patients. However, the accurate prediction was not improved and time consumption was not minimized. In order to address these existing problems, a novel technique called Biserial Targeted Feature Projection-based Radial Kernel Regressive Deep Belief Neural Learning (BTFP-RKRDBNL) is introduced to perform accurate disease prediction with lesser time consumption. The BTFP-RKRDBNL techniques perform disease prediction with the help of different layers such as two visible layers namely input and layer and two hidden layers. Initially, the features and data are collected from the dataset and transmitted to the input layer. The Point Biserial Correlative Target feature projection is used to select relevant features and other irrelevant features are removed with minimizing the disease prediction time. Then the relevant features are sent to the hidden layer 2. Next, Radial Kernel Regression is applied to analyze the training features and testing disease features to identify the disease with higher accuracy and a lesser false positive rate. Experimental analysis is planned to measure the prediction accuracy, sensitivity, and specificity, and prediction time for different numbers of patients. The result illustrates that the method increases the prediction accuracy, sensitivity, and specificity by 10, 6, and 21% and reduces the prediction time by 10% as compared to state-of-the-art works.

A visual mass transfer study in the ejector considering phase change for multi-effect distillation with thermal vapour compression (MED-TVC) desalination system

The multi-effect distillation with thermal vapour compression (TVC) seawater desalination system provides an excellent energy-saving scheme by escalating the low-level energy. The internal mass and heat transfer in ejectors is an important element to improve efficiency. In this study, a visual mass transfer simulation model considering real thermodynamic properties is used to observe the inner-mixing process. The assessment is from the perspective of visible mixing layer growth and the effect on entrainment ratio. As shown in the mass percentage distribution graph, there is an inescapable phase change on mixing layer boundary, where the wetness of wet steam can reach to 16.0%. Meanwhile, the mixing layer length predicted by dry model is 25.1% higher than wet model. The condensation weakens the mixing process and leads to shorter length. Under subcritical mode, the cross-sectional area of the entrained flow is deducted and the mixing layer cannot develop completely. The critical pressure range predicted without condensation is 18.5% lower, which causes a misjudgment in entrainment ratio because overvaluing the influence of outlet pressure on entrained flow. Thus, mass transfer during development of the two-phase mixing layer has great impact for MED-TVC system.

Natural Trap Cave tephra correlation to Yellowstone using U-series (230Th/238U) dates and oxygen isotopes of zircon and chemical composition of adherent glass

Zircon crystals from ash layers intercalated with fossil-rich sediment from Natural Trap Cave (NTC) in Wyoming (USA) were investigated to refine the chronostratigraphy of this unique late-Quaternary megafaunal assemblage. Glass compositions of individual glass spicules and glass adherent to zircon along with a characteristic low-δ18O signature of zircon (on average + 2.4‰ relative to Vienna standard mean ocean water) indicate tephra provenance from post-Lava Creek Tuff activity of Yellowstone. Yellowstone glass composition was hence used to anchor the 230Th/238U zircon isochron and to compute model crystallization ages, which translate into maximum depositional ages. For the lowermost visible tephra layer in new excavations in NTC strata, an upper age limit of 138 ± 9 ka (1σ age uncertainty) was thus obtained. A younger tephra with a230Th/238U zircon date of 111 ± 8 ka is tentatively correlated with Tuff of Cold Mountain Creek from the Central Plateau Member of Yellowstone, suggesting a minor lag time between zircon crystallization and eruption. The NTC tephra record thus has high potential for refining the explosive volcanic history and tephra distribution patterns of Yellowstone during the late Pleistocene.

A white dwarf accreting planetary material determined from X-ray observations.

The atmospheres of a large proportion of white dwarf stars are polluted by heavy elements1 that are expected to sink out of visible layers on short timescales2,3. This has been interpreted as a signature of ongoing accretion of debris from asteroids4, comets5 and giant planets6. This scenario is supported by the detection of debris discs7 and transits of planetary fragments8 around some white dwarfs. However, photospheric metals are only indirect evidence for ongoing accretion, and the inferred accretion rates and parent body compositions heavily depend on models of diffusion and mixing processes within the white dwarf atmosphere9-11. Here we report a 4.4σ detection of X-rays from a polluted white dwarf, G29-38. From the measured X-ray luminosity, we derive an instantaneous accretion rate of [Formula: see text], which is independent of stellar atmosphere models. This rate is higher than estimates from past studies of the photospheric abundances of G29-38, suggesting that convective overshoot may be needed to model the spectra of debris-accreting white dwarfs. We measure a low plasma temperature ofkBT = 0.5 ± 0.2 keV, corroborating the predicted bombardment solution for white dwarfs accreting at low accretion rates12,13.

Ultrasound device as a minimally invasive approach for caries dentin removal.

The aim of this study was to evaluate the efficacy of an ultrasound device and the dentin surface morphology after removal of the caries dentin lesions by removal rate and scanning electron microscopy (SEM). The Knoop hardness test on the bovine dentin blocks (n = 20, 4x4x2mm) was performed to standardize the samples and only those with 38 ± 2 KHN were included. The dentin blocks were submitted to induction of artificial caries lesions, using the bacterial model. Strains of Streptococcus mutans and Lactobacillus acidophilus were used for 7 days. The caries dentin lesion was removed for 1 min, according to two methods: G1 - carbide bur under low-speed rotation (control group) and G2 - ultrasound device under refrigeration. For the removal rate, the samples were weighed 3 times: T0 (before induction), T1 (after induction) and T2 (after removal). Morphology evaluation of the residual dentin surface was performed by SEM. Data normality was verified by Shapiro-Wilk test (p ≥ 0.240). T-test for independent samples was applied to evaluate the removal rate. A significance level of 5% was adopted. G2 provided lower removal rate than G1 (G1: 3.68 mg and G2 = 2.26 mg). SEM images showed different morphological characteristics between the groups. G2 showed absent of smear layer, while G1 showed a visible smear layer over the surface. We concluded that ultrasound device provides minimally invasive removal with residual dentin exhibiting open dentin tubules and no smear layer formation and no bacteria, which infer the removal of the infected tissue.

The university students’ viewpoints on e-learning system during COVID-19 pandemic: the case of Iran

The outbreak of COVID-19 closed educational institutions and universities. The aim of this study was to explain the strengths and weaknesses of the e-learning system in Iranian universities of medical sciences in the COVID-19 pandemic. This is a qualitative study that was conducted with students enrolled in Iranian medical universities. Data was collected through an open-ended electronic questionnaire based on the interview guide and was analyzed through content analysis.122 students from 46 medical universities participated in this study. 122 questionnaires from 46 universities of medical sciences were completed. From a total of 54 codes extracted from the results, seven (strengths/positive experiences) and six (weaknesses/challenges) themes were extracted, each of which had several subsets. E-learning has both visible and hidden layers in terms of advantages and disadvantages. The e-learning system is an essential tool to continue education during the COVID-19 pandemic. Most students believe that e-learning was a great complement to prevent academic failure, but it cannot replicate the same efficiency of face-to-face training.

The Design of Adolescents' Physical Health Prediction System Based on Deep Reinforcement Learning.

According to the general recognition in the first half of the last century, hypertension was not considered a kind of disease, but was regarded as a compensatory response commonly seen in the elderly, and it would not occur to younger people. Because of this erroneous cognition, many young patients fail to pay attention to their own hypertension, fail to take correct and standardized treatment, and suffer from a series of complications caused by hypertension. This article summarizes the relevant factors that affect the patient's future blood pressure from three directions: the basic characteristics of adolescent patients, the way they lower blood pressure, and the impact of the external environment. In order to make the model better fit the continuous data in the feature set of adolescents with hypertension, the structure of the internal components of the deep confidence network is optimized. Gaussian noise is introduced into the visible and hidden layers of the internal components of the network so that the stored information of the network changes from discrete to continuous during operation and improves the prediction accuracy of the blood pressure prediction model for adolescents with hypertension.