Layering Research Articles

Partitioned inclined enclosure with an air layer and Nano-enhanced-PCM for electronic cooling application

Partitioned inclined enclosure with an air layer and Nano-enhanced-PCM for electronic cooling application

A Study of Color Palettes and Painting Techniques of Prayat Pongdam: Oil on Board Painting “Cats and Birds (1957)” Using Micro-XRF Scanning Technique

This work presents the characterization of the pigments in the painting by Prayat Pongdam, one of the most essential artists in the history of Thai contemporary art. The painting that was studied is named “Cats and Birds (1957),” oil on board, from the collection of a private collector. XRF measurements were carried out utilizing a portable system and mapping scanning. XRF revealed substantial information about the pigments in the painting and the artist’s technique. Lead white (Pb) was presented in or near the ground layer. A mixture of barium (Ba) and titanium (Ti) was applied in almost all areas but less in the blue areas, presumably because these two pigments were used on top of the ground layer. Zinc (Zn) white was mixed with the cerulean blue (Co, Sn) for the blue regions. Chromium-based green (Cr) and red ochre (Fe) were in the palette in green and red areas, respectively. A layer of gold was applied to some areas, assuming the artist wanted to make it a highlight. Metallic pigments containing copper (Cu) were also revealed.

Assembly and Testing of Ground Layer Adaptive Optics (GLAO) for ARIES Telescopes

This project is focused on evaluating the slowly-varying ground layer seeing component at the optical telescopes of ARIES. To achieve this, we assembled the instrument, consisting of a filter wheel, a CCD camera, and a tip-tilt enabled transparent glass plate integrated within an off-the-shelf unit termed as the AO (Adaptive Optics) unit. The instrument developed by us was deployed on the 1.04-m f/13 Sampurnanand telescope at Manora Peak and the 1.3-m f/4 telescope at Devasthal. This instrument measures the average instantaneous slope (tip/tilt) of the incoming wavefront over the telescope aperture via a fast (within the atmospheric coherence time) sampled image and corrects it via a software-controlled oscillating (tipping/tilting) single thin glass plate. The night observations revealed that the slowly-varying seeing component is significant at both observatories and can be effectively controlled to enhance the sharpness of the celestial images at the two sites. The most significant improvement was measured from 5 arcsec of uncorrected FWHM of a star to 3.4 arcsec of corrected FWHM in the 1.04-m telescope in the evening hours.

МОДЕЛЬ ТЕПЛО-ВЕТРОВОГО РЕЖИМА НАРУЖНЫХ СТЕН ЗДАНИЙ С ЖАЛЮЗИЙНЫМ СОЛНЦЕЗАЩИТНЫМ УСТРОЙСТВОМ

The article discusses the energy efficiency of walls with louvered sun shading devices. It has been noted that louvered façade systems with a ventilated layer are an effective means of protection from solar radiation in summer. As a result of the experimental studies carried out on building models, a number of significant thermophysical regularities were noted that determine heat and wind processes in the near-wall layer of facade systems, which can rightfully be applied in the actual design, construction and operation of objects. Prerequisites and conditions have been created for the development of a universal methodology for assessing heat and wind processes, determined by geometric and physical similarity when modeling processes in the near-wall air environment in solving architectural and structural problems of various compositions. It has been established that the effectiveness of ventilation of the wall layer of air and the first unbuilt column floor is achieved by using façade louvered sun-protection devices with an angle of inclination of their lamellas of 45° - 60° to the plane of the facade during their insolation. The energy efficiency of building walls was revealed through the use of sun-protection louver devices. Prerequisites for the architectural and construction design of external walls with louvered sun-protection devices have been determined that contribute to the formation of convective flows in the wall layer of air, which can subsequently be used for heating premises, as well as for extracting exhaust air from premises by determining the location of natural supply and exhaust openings and the operating mode of windows sashes, transoms, vents.

Drag reduction on micro-trench and micro-post superhydrophobic surfaces underneath a motorboat on the sea

Superhydrophobic (SHPo) surfaces can capture a thin layer of air called a plastron under water to reduce skin friction. Although a ~30 % drag reduction has been recently reported with longitudinal micro-trench SHPo surfaces under a boat and in a towing tank, the results lacked the consistency to establish a clear trend. Designed based on Yu et al. (J. Fluid Mech, vol. 962, 2023, A9), this work develops and tests a series of high-performance SHPo surface coupons that can sustain a pinned plastron underneath a passenger motorboat revamped to reach 14 knots. Importantly, plastrons in a pinned state, not just their existence, are confirmed during flow experiments for the first time. All the drag-reduction data measured on different longitudinal micro-trenches are found to collapse if plotted against slip length in wall units. In comparison, aligned posts and transverse trenches show less and little drag reduction, respectively, confirming the adverse effect of the spanwise slip in turbulent flows. This report not only verifies SHPo surfaces can provide a consistent drag reduction at high speeds in open sea but also shows that one may predict the amount of drag reduction in turbulent flows using the physical slip length obtained for Stokes flows.

Study on non-destructive and quantitative detection of air layer thickness in film rolls

Study on non-destructive and quantitative detection of air layer thickness in film rolls

Improving transmission loss performance of aluminum extrusion in railway vehicles using lightweight material

This study developed a method for improving the transmission loss performance of aluminum extrusion by reinforcing the inner space of the extruded material with a lightweight material, such as acrylic plastic. First, the dynamic characteristics of the aluminum extrusion were analyzed, and the characteristics of noise transmission were evaluated through an acoustic mode analysis of the air layer for the inner space of the extruded material. Furthermore, to improve the transmission loss performance of the aluminum extrusion, methods were developed for increasing the vibration stiffness and altering the acoustic mode of the inner space. Additionally, a simulation analysis of the vibration mode and a response analysis based on the excitation of sound were performed to validate the proposed model; the effectiveness of the model for noise and vibration reduction was compared with that of the existing model. This analysis was conducted using models wherein the acrylic plastic was partially and totally inserted into the interior space of aluminum extrusion. The results indicated that the noise performance of the short reinforcement model with the partially inserted acrylic plastic was improved by 3 dB and that of the long reinforcement model with the totally inserted acrylic plastic was degraded by > 4 dB compared with the existing aluminum panel.

Numerical Evaluation of Harmful Consequences after Accidental Explosion at a Hydrogen Filling Station

Abstract This study aims to present computational technology that can be used to evaluate numerically the harmful environmental consequences caused by an accidental hydrogen release from failed high-pressure dispensing cylinders and its explosion at a vehicle hydrogen filling station. A coupled problem of a hydrogen explosion products expansion in the atmospheric ground layer and a harmful explosion pressure wave shock impact on service personnel and infrastructure buildings at an accident site is solved by means of computer experiment simulation series. A spatial time-dependent model of compressible hydrogen-air mixture flow is used to obtain pressure history in calculation area in order to assess maximum overpressure in control points of human possible locations and on building surfaces exposed to hydrogen blast wave impact. A deterministic impact consequences model is based on comparing maximum overpressure values extracted from the mathematical model with threshold ranges corresponding to certain degrees of human damage and infrastructure destruction. The presented computer technology allows safety experts to identify potentially dangerous zones by means of mathematical modelling and recommend effective protection measures to mitigate negative consequences of explosions.

Fractional Mathieu Differential Equations in Dynamic Stability of Piles

Piles are commonly used in Civil and Mechanical Engineering to provide support to superstructures and to transmit loads to deeper ground layers. During earthquakes, pile instability can result in the collapse of the entire structure. In this paper, the pile is modeled as a column surrounded by Winkler soil foundations with fractional damping. Investigation of the axially loaded pile leads to a fractional Mathieu differential equation of motion. The Bolotin method, employing harmonic balance, is proposed to obtain the approximate instability boundaries of the pile in the stability diagrams. A practical example is presented to conduct a parametric study on pile instability concerning the fractional order. The study observes parametric resonance in the first order, representing the principal instability region, which requires special attention to maintain stability. Furthermore, increasing the fractional damping order leads to a higher critical dynamic load and a slight reduction in the critical frequency ratio in each instability region. Higher-order instability regions exhibit greater sensitivity to changes in the fractional order. These results provided insights into the stability of piles under earthquake conditions.

Modelling the Spatial Distribution of Industrial Facilities and Green Areas to Reduce the Ecological Footprint

The work solves conjugated problems of a stationary and non-stationary nature for the processes of transfer and diffusion of harmful substances into the atmosphere emitted by industrial facilities to protect the ecology and environment from man-made factors. When mathematically modelling mass transfer in air, absorption coefficients were considered depending on climatic conditions and external disturbances, as well as adhesion coefficients of aerosol particles with vegetation and other weather and climatic factors. Analytical solutions and dual functionality were obtained, and solutions have been developed to optimize the location of industrial facilities in the region from the perspective of economic development and environmental protection. Numerical calculations have shown that the efficiency of particle capture by vegetation is a key factor depending on the type and size of vegetation and varying throughout the year. Experiments have confirmed that the concentration of harmful substances in the ground layer of the atmosphere decreases with increasing coefficients of absorption and capture of particles by vegetation. Computational experiments carried out on a computer have established that with an increase in the diffusion coefficient, the zone of distribution of pollutants expands.

New insight from MALDI-TOF MS and multivariate data analysis on the botanical origin of polysaccharide-based paint binders in ancient Egypt.

Polysaccharide-based materials of plant origin are known to have been used as binding media in paint and ground layers of artifacts from ancient Egypt, including wall paintings, cartonnages and sarcophagi. The use of gums from Acacia, Astragalus and Prunus genera has been suggested in the literature on the basis of their qualitative or quantitative monosaccharide profile after complete chemical hydrolysis. The introduction of partial enzymatic digestion of the polysaccharide material, followed by analysis of the released oligosaccharides by matrix assisted laser desorption ionization-time-of-flight mass spectrometry, has proved effective in discriminating among gums from different genera, as well as among species within the Acacia genus. In this study, the previously built Acacia database was expanded, principal component analysis (PCA) was used to aid in grouping of the samples, and data interpretation was refined following a modified acacieae taxonomy. Application of the analytical strategy to investigate the paint binders in artworks from ancient Egypt allowed qualitative discrimination of gums at a species level, and provided new insights into the artists' material choices.

Ignition probability and fuel consumption of boreal ground vegetation fuels – an experimental study in Finland

In boreal forests fires often ignite and spread within the dominant moss and lichen cover of the ground layer vegetation, which thus greatly influences fire hazard. We used an experimental set-up in greenhouse conditions to study the differences in how (1) fuel moisture and (2) wind velocity influence the ignition probability and fuel consumption among four common circumboreal ground vegetation fuels, Pleurozium schreberi (Willd. ex Brid.) Mitt., Hylocomium splendens Schimp., Dicranum spp. and Cladonia rangiferina (L.) F. H. Wigg. Our results show that the reindeer lichen C. rangiferina was clearly the most flammable species, with high ignition probability even at high moisture contents and low wind velocities. Of the mosses, Dicranum was the least flammable, with low ignition probability and mass loss at low wind velocities regardless of moisture content. P. schreberi and H. splendens behaved somewhat similarly with wind velocities quickly increasing the initially low ignition probability and mass loss observed in the absence of wind. However, especially for mass loss, among-species differences tended to disappear with stronger winds. The observed differences can be explained by the different structures and growth forms of the studied species and open a potential avenue for improving forest fire risk predictions.

Ambient air quality in the area of open car parks of mixed-up complexes in Murmansk

Recently mixed-up complex and large shopping and entertainment centers have started to appear beyond the Arctic Circle more often, therefore the impact of vehicles located in these areas on the ambient air of the city is of particular interest. The article is considering atmosphere air pollution in the area of open car-parks of such centers in Murmansk, located in the Arctic zone of the Russian Federation. The article describes the characteristics of the two largest shopping and entertainment centers in the city, which have open car parks at their territory. There are pedestrian zones near the car parks, and the main flow of visitors is forced to pass through the territory to get to the shopping and entertainment center, being exposed to the influence of car emissions. Parallel measurements of NO2 and CO content in the ground layer of the atmosphere on the territory of open parking lots were carried out. It was found that the distribution of NO2 and CO on the territory of car parks is uneven and depends on the presence of traffic lights, pedestrian crossings, artificial unevenness, proximity to the road, year season and other factors. The measurements were taken during the coronavirus pandemic, when grocery stores in shopping and entertainment centers became the main places of people and vehicles congestion.

Elevated Mixed Layers during Great Lake Lake-Effect Events: An Investigation and Case Study from OWLeS

Abstract Data from rawinsondes launched during intensive observation periods (IOPs) of the Ontario Winter Lake-Effect Systems (OWLeS) field project reveal that elevated mixed layers (EMLs) in the lower troposphere were relatively common near Lake Ontario during OWLeS lake-effect events. Conservatively, EMLs exist in 193 of the 290 OWLeS IOP soundings. The distribution of EML base pressure derived from the OWLeS IOP soundings reveals two classes of EML, one that has a relatively low-elevation base (900–750 hPa) and one that has a relatively high-elevation base (750–500 hPa). It is hypothesized that the former class of EML, which is the focus of this research, is, at times, the result of mesoscale processes related to individual Great Lakes. WRF reanalysis fields from a case study during the OWLeS field project provide evidence of two means by which low-elevation base EMLs can originate from the lake-effect boundary layer convection and associated mesoscale circulations. First, such EMLs can form within the upper-level outflow branches of mesoscale solenoidal circulations. Evacuated Great Lakes–modified convective boundary layer air aloft then lies above ambient air of a greater static stability, forming EMLs. Second, such EMLs can form in the absence of a mesoscale solenoidal circulation when Great Lake–modified convective boundary layers overrun ambient air of a greater density. The reanalysis fields show that EMLs and layers of reduced static stability tied to Great Lakes–modified convective boundary layers can extend downwind for hundreds of kilometers from their areas of formation. Operational implications and avenues for future research are discussed.

JUSTIFICATION OF THE FEASIBILITY OF NORMALIZING THE LEVEL OF GREENING OF SANITARY AND PROTECTIVE ZONES OF OPERATING QUARRY ROCK DUMPS IN THE CONTEXT OF SUSTAINABLE DEVELOPMENT

To reduce the impact of polluted air on human health it is important to expand the areas of green spaces and create healthier conditions for the local population to live and reproduce biodiversity. Dumps of overburden the surface of which has reached intensive self-overgrowth with grass and tree-shrub vegetation and the industry of the adjacent land should be considered as fabricated objects with a high potential of gas-absorbing capacity of pollutants from the surface layer of atmospheric air. A comparison of the amount of emissions of pollutants which are directly during the dumping of overburden dumps with the ability of vegetation to adsorb them during the growing season revealed the following: rather high indicators of the absorption capacity for sulfur oxide and the ability to self-clean the surface layer of the air as well as an additional balance of regenerated oxygen due to green vegetation. Calculations of emissions of pollutants and greenhouse gases into the atmosphere from vehicles were made taking into account unloading operations from the dumping of mining mass into a dump and taking into account their formation during the combustion of fuel from internal combustion engines of special equipment according to specific indicators. The analysis of the cartographic material showed a sufficient level of greening of the sanitary and protective zone of the dumps in accordance with the territory planning recommendations. The possibility of self-cleaning of the surface air layer should be considered during the preparation of relevant environmental impact assessment reports of the planned economic activity and during the planning of dumping, the volumes of which are related to the gradual advancement of the work front in the quarry. This will make it possible to consider industrial lands with a high level of greening as one of the ways to increase the ESG rating of economic activity in terms of the impact of environmental risks on atmospheric air quality and its minimization due to a sufficient level of industrial lands greening.

Trial for the propagation method in Flemingia spp., a shrub plant and a lac insect host in Thrissur, Kerala

Due to the challenges posed by the poor availability and germination of Flemingia spp. for lac insect cultivation, the Kerala Forest Research Institute in Thrissur experimented with the air layering method and stem cutting (Vegetative Propagation) to enhance the number of seedlings. The layering method was successful for all three treatments, although it is observed variations in the length of the roots. The plant treated with coco peat exhibited longer roots and a greater number of roots, followed by the plants treated with only soil and vermiculite. The stem cutting method (vegetative propagation) was also successful for both plants, suggesting that both techniques can be used as alternatives for cultivating lac insect host plants instead of relying on seed germination.

HYGIENIC ASSESSMENT OF THE IMPACT OF OFF-GRID HEAT SOURCES ON AMBIENT AIR QUALITY AND THE FORMATION OF PUBLIC HEALTH RISKS

Background. The study is relevant due to a significant number (more than 74 thousand) of autonomous heat sources (AHS) in the Russian Federation, especially in its eastern regions. Such sources use solid fuels (coal). AHS, along with other heat and power objects, make a considerable contribution to ambient air pollution in the ground layers and consequently produce harmful effects on public health.
 The aim of this study was to perform hygienic assessment of negative effects produced by autonomous heat sources (AHS) on ambient air quality, health risks and additional associated incidence on the example of a territory included into the Clean Air Federal project.
 Materials and methods. We calculated dispersion of pollutants in ambient air in residential areas due to AHS; performed hygienic assessment of calculated and instrumental data on ambient air quality; assessed public health risks; identified the number of additional associated diseases in accordance with the conventional established methods and algorithms valid at the present moment.
 Results. More than 170 AHS are located on the analyzed territory; they all use soli fuel (coal). Hygienic standards are violated in areas influenced by AHS for four out of sever chemicals emitted by chimneys of private houses. Pollutant levels reach 5.1 single maximum MPC for four pollutants according to dispersion calculation; 4.8 single maximum MPC, 38 average daily MPC and 4.7 average annual MPC for four pollutants according to instrumental data; 29.9 single maximum MPC, 3.5 average daily MPC and 7.0 average annual MPC for three pollutants according to verified data. Identified carcinogenic, acute, and chronic health risks are ranked as ‘alerting’ and ‘high’ in areas under direct influence of AHS; these risks reach 13.4 HQ (acute), 7.0 HQ (chronic), CRT 1.19∙10-7 (carcinogenic). AHS create more than 11 thousand additional respiratory diseases (6,379.9 cases per 100 thousand people); of them, 98% cases are registered in children.
 Conclusion. AHS create high levels of exposure to harmful pollutants and elevated health risks as well as additional incidence associated with ambient air quality. This situation requires immediate attention of the local authorities, control and surveillance organs; it is necessary to develop and implement complex air protection activities as soon as possible.

Simulation and performance assessment of a heat pump coupled to a sub-slab thermal storage system

The paper explores the performance of a sub-slab ground heat exchanger, coupled to a heat pump, and the ability of the system to provide space conditioning and domestic hot water (DHW) for a multi-unit residential building (MURB) located in Ottawa, Ontario. The parametric analysis conducted to optimize the design of the building, as well as the sensitivity analysis performed to optimize the configuration of the sub-slab ground heat exchanger is also presented. According to the simulated results, the ground layer can store some of the rejected energy over medium term, without reducing the long-term performance of the heat pump. The annual energy consumption per dwelling unit (including heat pump, all auxiliary equipment, appliances, and lights) was estimated to be 28.4 GJ, significantly lower than the average annual energy consumption for a low-rise apartment in Canada (46.7 GJ per apartment). To assess the sensitivity of the system to environmental conditions, the simulation was conducted using the weather files for other five locations in Canada.

Impalement-Resistant, Mechanically Stable, and Anti-Static Superamphiphobic Coatings Enabled by Solvent Regulation and Their Application in Anti-Icing.

Superamphiphobic coatings have good application prospects in many fields but are limited by their low impalement resistance, weak mechanical stability, and easy adhesion of tiny droplets. Here, impalement-resistant, mechanically stable, and antistatic superamphiphobic coatings were fabricated by spraying a mixture of conductive carbon black (CB), silicone-modified polyester adhesive/fluorinated SiO2 microspheres onto Al alloy. The microspheres were obtained by adhesive phase separation and the binding of fluorinated SiO2 to them. The morphology, superamphiphobicity, impalement resistance, and mechanical stability of the coatings could be regulated by using solvents with different boiling points. As a result, the coatings simultaneously exhibited outstanding mechanical stability, impalement resistance, and superamphiphobicity. The addition of conductive CB endowed the coatings with good antistatic and tiny droplet repellent properties. In addition, the coatings exhibited good anti-icing properties due to the steady air layer at the solid-liquid interface and the very small contact area between them. We suppose that the coatings are very promising for practical application in various fields, including anti-icing, due to their outstanding comprehensive properties and simple preparation process.

(Invited) Modified SAB Methods for Hybrid and All-Cu Bonding for 3D Integration below 200ºC

Two methods of Surface Activated Bonding (SAB) will be proposed to enable low-temperature hybrid bonding for 3D integration.A modified one involves surface activation processes using Ar fast-atom-beam bombardment with simultaneous co-sputtering of Si nano-adhesion layer, followed by sequential plasma irradiation with N2 radicals. These processes combine hydrophilic treatment and bonding in a low-vacuum chamber. The Si nano-adhesion layer and the sequential plasma treatment appear to enhance hydrophilicity, which enables low-temperature bonding of both Si oxides and Cu pads as hybrid bonding. Bonding in a low-vacuum environment helps to avoid void generation caused by air entrainment.The other one is the standard SAB. But we will connect two device wafers not in a hybrid bonding but in all-Cu bonding. A small insulation layer surrounds the area around the Cu electrode on the wafers, while the rest is covered with Cu solid layers. These solid layers constitute the ground layer, power layer, or their paired layers and may contribute to heat dissipation when connected to thermal vias. The two wafers are connected only by bonding on the Cu electrodes and solid layers. The insulating parts around the Cu electrodes do not necessarily have to be bonded, and the gaps may be kept in a vacuum. Of course, the bonded surfaces need to be flattened, and a new division and layout design of the solid electrode will be required.Cu-Cu direct bonding is possible at room temperature by applying the standard SAB directly. Of course, this requires bonding in an ultra-high vacuum condition, which inevitably reduces the throughput. However, room temperature bonding is overwhelmingly advantageous for bonding different types of devices and wafers. It is expected to become a powerful tool for 3D heterogeneous integration of devices in the future. Figure 1