Mesh Box Research Articles

Electrochemically fast preparation of superhydrophobic copper mesh for high-efficiency oil spill adsorption and oil-water separation

Oily wastewater and marine oil spills are a massive environmental and human threat. Conventional oil spill treatment methods include adsorption by absorbent materials, dispersants or adsorbents, and in situ burning. Superhydrophobic materials, as a material that can achieve oil-water separation, have great potential for application in oil spill treatment. Research on superhydrophobic oil spill treatment mainly focuses on materials such as sponges and fabrics. Although these materials can effectively perform oil-water separation or oil spill adsorption, they also have the disadvantages of complicated preparation methods and high costs. Here, we present a miniature device for oil-water separation and oil spill collection and recovery. The superhydrophobic copper mesh box can be used on its own as an oil-water separation device or in combination with a commercial polyurethane sponge as a miniature oil-absorbing device. The robust copper mesh is prepared in two steps: anodizing and impregnation. The superhydrophobic copper mesh had a high oil separation flux (32,330 L m−2 h−1) and efficiency (97%), which remained high (28,560 L m−2 h−1) and efficient (95%) after 20 cycles of separation. The combined micro oil adsorption device can adsorb different oils and fats on the water surface, and it has good reusability with oil adsorption capacity and efficiency up to 15.28 g/g and 98% and still has good oil adsorption capacity (11.54 g/g) and efficiency (94.6%) after 20 cycles of adsorption. Therefore, the prepared micro oil-absorbing device has promising application prospects in oil-water separation, oil spill cleanup, etc. Environmental ImplicationThis study demonstrates a facile electrochemical approach to prepare a miniature device for high-efficiency oil-water separation and oil spill collection and recovery. The modified copper mesh's separation flux could reach 32,330 L m−2 h−1, showing great promise in oil-water separation and oil spill cleanup.

Study on Aeolian Sand-Box Backfill Geomechanical Characteristics and Overlying Strata Control Effects

The aeolian sand-box backfilling method proves effective for environmentally friendly coal extraction in northwestern regions, including Xinjiang. This study investigated the geomechanical characteristics of aeolian sand-box backfill material and its control effects on overlying strata through indoor experiments, mechanical analysis, and numerical simulations. Uniaxial compression tests on models with varying mesh sizes, wire diameters, and dimensions revealed that larger mesh sizes and wire diameters increased the bearing capacity of the aeolian sand-box backfill material, while increasing dimensions had the opposite effect. A mechanical analysis of the metal mesh box deformation produced equations describing its restraining force. Subsequent experiments and simulations on models of different dimensions consistently demonstrated the material’s mechanical properties, with stress-displacement curves closely aligned. 3DEC5.2 software simulations highlighted the effectiveness of aeolian sand-box backfill material in controlling displacement and stress variations in goaf areas. Notably, smaller-sized backfill material exhibited a more pronounced impact on controlling overlying strata displacement and stress development.

Deflection prediction of assembly integral steel-concrete floor voided with steel mesh boxes

Steel-concrete assembled hollow core slabs have witnessed widespread adoption in recent years owing to their inherent advantages of reduced self-weight, enhanced rigidity, and superior integrity. Nonetheless, to achieve extended spans and expedite on-site construction, further optimization of the connections and fillers in these assembled slabs is imperative, along with fortifying the overall structural performance. Therefore, this study introduces a novel variant of assembly integral steel-concrete composite floor, incorporating voids filled with steel mesh boxes, which utilizes four prefabricated slabs featuring hidden transverse and longitudinal girders and a steel frame system. Concurrently, a large-scale experiment was conducted to explore its mechanical and deformation recovery performance. The detections indicate that this innovative structure exhibits excellent integrity, as the four prefabricated components transform from individual one-way slabs into a continuous floor, facilitating the efficient transmission of forces in multiple directions. A finite element model was established to provide ideas for the research of scholars in allied domains and a fundamental framework for the subsequent parametric analysis of the structure. Building upon the analog cross-beam method, the deflection of the novel structure is calculated. The resulting discrepancy between the calculated and experimental results is merely 1.87%, attesting to the practical applicability of this method. These findings provide a solid foundation, both experimentally and theoretically, for the future design and engineering application of composite slabs, fostering the advancement of sustainable construction practices.

Local Inverse Mapping Implicit Hole-Cutting Method for Structured Cartesian Overset Grid Assembly

An automatic hole-cutting method is proposed to search donor cells between a structured Cartesian mesh and an overlapping body-fitted mesh. The main flow is simulated on the structured Cartesian mesh and the viscous flow near the solid boundary is simulated on the body-fitted mesh. Through the spatial interpolation of flux, the surface boundary information on the body-fitted mesh is transferred to the Cartesian mesh nodes near the surface. Cartesian mesh box near a body-fitted mesh cell is selected as a local inverse map. The Cartesian nodes located inside the donor cells are marked by the relative coordinate transformation, so that all Cartesian nodes can be classified and the hole boundaries are implicitly cut. This hole-cutting process for overset grid assembly is called Local Inverse Mapping (LIM) method. In the LIM method, spatial interpolation of flux is carried out synchronously with the marking of Cartesian nodes. The LIM method is combined with the in-house finite-difference solver to simulate the unsteady flow field of moving bodies. The numerical results show that the LIM method can accurately mark the Cartesian hole boundary nodes, the search efficiency of donor cells is high, and the result of spatial interpolation is accurate. The calculation time of overset grid assembly (OGA) can be less than 3% of the total simulation time.

Flexural performance of assembly integral floor structure voided with steel mesh boxes

Enhancing the ease of construction of fillers and large-span floors and their overall mechanical performance is critical for prefabricated hollow slabs in modular building structures. Therefore, we propose a novel assembly integral two-way hollow floor structure (8.4 × 8.4 m) consisting of permanent fillers (BDF ribbed steel mesh box) and three precast one-way hollow-core slabs with I-shaped flexural sections to address the above problem. This report evaluates the overarching flexural mechanism of a large-span full-scale model of the proposed system under uniform vertical loads. The experiment supports that the structure possesses a high bi-directional vertical bearing capacity and achieves the purpose of turning three one-way precast slabs into a two-way integral floor. The deflection value of the cast-in-site concrete frame beam, as the junction between the precast and cast-in-situ sections, is 88% below the damage limit value in GB/T 50152–2012. The strain of the bottom rebars in the ribbed girder of the precast hollow slab is identical to in the hidden girder. The strain profile in the mid-span of the frame beam reveals a noticeable membrane effect, strengthening the bending resistance of the system. Additionally, the original structure was modeled using ABAQUS to study the damage mechanism further. The analysis of the plastic development history and stress-strain distribution of the specimen reveals that upgrading the concrete strength has a slight improvement on the stiffness but could lessen its damage. While rationalizing the steel configuration is a more cost-effective option. Based on the pseudo-plate method and simulation results, the deflection and internal force equations were also recommended for preliminary design.

Escarabeídeos (Coleoptera: Scarabaeidae) de importância forense ocorrentes em carcaça suína nos municípios de Caxias do Sul e Bento Gonçalves, Rio Grande do Sul - Brasil

The Scarabaeidae group has great forensic relevance mainly because some of its representatives have necrophagous habits. In this way, these insects offer the potential to provide important criminal information related to cadavers in advanced stages of decomposition. The objective of this work was to identify and quantify the species of scarabids that occur in swine carcasses in the cities of Caxias do Sul and Bento Gonçalves, Rio Grande do Sul - Brazil. The collections were carried out in three stages: in a private property located in the Ana Rech district in Caxias do Sul and two in Bento Gonçalves in the University district. The carcasses (Sus scrofa) were placed in lateral decubitus under a metal mesh box surrounded by ten soil traps. A total of 75 individuals belonging to the Scarabaeidae family were collected (14 species), and the species are distributed in the subfamilies: Aphodiinae, Dynastinae, and Scarabaeinae. The taxa found were included in the tribes: Eupariini, Cyclocephalini, Coprini, Deltochilini, Oniticellini, Onthophagini, and Phanaeini. Differences were found between the occurrence of taxa in the two cities evaluated, Stenocrates Burmeister, 1847 was found exclusively in Bento Gonçalves, while the Onthophagus Latreille, 1802 exclusively in Caxias do Sul. The results demonstrate the importance of specimen collection in several places to allow an adequate practice of Forensic Entomology. It should be noted that the southern region of Brazil has great potential for forensic studies.

Scheme Design of Returnable Transportation Packaging System between Shandong Province and South Korea

The main trade product categories and logistic packaging standard systems were firstly investigated between Shandong province and South Korea. Based on the results, the auto parts were chosen as the target product to design the returnable transportation packaging system. Therefore, the system composed of standardized plastic pallet, nested plastic returnable box and top cover were designed for the light auto parts, while the folding visualized metal mesh box was designed for the heavy auto parts. By simulating the adaptability among different specifications of packaging equipment and the shipping containers, the recycling plastic pallet with size of 1140 mm×980 mm, plastic packaging boxes with size of 480 mm×380 mm were preferred to match 40 ft containers, the plane and space loading efficiencies of which are 94.89% and 87.35%, respectively. While, the metal mesh boxes with 1000 mm×800 mm×760 mm were preferred to match with 20 ft containers, with the plane and space loading efficiencies of 94.89% and 87.35%, respectively.

N-Gram Language Model to Predict the Word Sequence in a Degraded Braille Document

This paper presents a feature extraction method for optical Braille recognition (OBR) system to locate, extract and convert the Braille cells in one sided Indian language Braille documents. The Braille cells are located by implementing a grid-box designed using physical properties of a Braille cell. A Braille document image is a compilation of group of six dots. The physical position of each dot and its relevance with other neighboring dots in a single cell gives various Braille characters. After the grid-box is mapped with the Braille cells in the document, the mesh characters are extracted and are then mapped with existing database to translate them in required text. Mapping of Braille cells with mesh box and separation of characters and words from a Braille document was a challenging task. The unwanted dots or degraded dots way result in incorrect mapping of characters. In this paper we have used N-gram Language Models to Predict the word Sequence in case of wrong mapping of characters in extraction and conversion of the Braille cells.

Experimental investigations on spontaneous combustion of pulverized coal in the oxyfuel combustion system

CCS (Carbon Dioxide Capture and Storage) is one of the technologies able to adequately displace CO2 from fossil fuel fired power plants and the only technology capable of reducing large-scale emissions. In particular, coal emits a lot of CO2, although it is an important energy resource in terms of energy security. To address this situation, IHI had developed oxyfuel combustion technology to capture CO2 from coal-fired power plants, and the demonstration using a 30MWe unit in Australia was successfully carried out. In order to commercialize the technology widely, how to configure the primary gas system is one of the important examination items. When adding oxygen into the primary gas system, depending on the type of mill, pulverized coal deposited in the mill may ignite spontaneously. To investigate the spontaneous combustion characteristics of the deposited pulverized coal under oxyfuel conditions, therefore, laboratory-scale experiments were carried out. The pulverized coal was deposited in a 100mm square mesh box, and it was installed in a thermostatic chamber. Then the mixed gas of N2/O2 or CO2/O2 was introduced into the chamber, and the temperature in the coal sample was measured. From the results, there was little temperature difference at which spontaneous combustion occurred between N2/O2 and CO2/O2 atmosphere, while there was a tendency that it might be relatively hard to occur under CO2/O2 atmosphere. The results also showed a tendency that the influence of temperature was stronger than the oxygen concentration.

Failures of Gabion Walls

Retaining wall is an important structure of any infrastructure. Due to research and advancement in Civil Engineering use of new types of retaining walls are very much common in recent construction scenario. Gabion retaining wall is one of the new types of retaining wall. Gabion wall consists of stone filled metallic mesh boxes which are tied together to form a shape of retaining wall. Gabion wall is very much common nowadays due to its simplicity, speedy construction, and flexibility. In spite of massive structure of Gabion wall there are possibilities of Gabion wall failures. Literature review shows that very less information is reported on failures of Gabion wall. This paper focused on defects/ failures observed in existing Gabion walls. Total 11 sites of existing Gabion walls around Pune district (India) are considered for the study. Investigations of these sites are made to identify various defects/failures with possible reasons. Remedial measures to overcome these deflect/failures are also suggested. Such a study will be helpful not only to avoid failures but also to provide a basis for possible research and modifications in the Gabion wall.

Construction of superhydrophobic copper film on stainless steel mesh by a simple liquid phase chemical reduction for efficient oil/water separation

Herein, we present a simple, easily operated, and inexpensive approach to fabricate superhydrophobic and superoleophilic stainless steel mesh via in-situ growth of copper (Cu) nanoparticles and the hydrophobic modification. The obtained meshes exhibit favorable resistance to mechanical abrasion, corrosive aqueous solutions, and hot water (90 °C). More importantly, the fabricated meshes can be used to separate a series of oil/water mixtures under harsh (hot or corrosive water) conditions with a separation efficiency of over 98%. Besides, the mesh can be designed into an oil collector via loading unmodified polyurethane (PU) sponge in the folded mesh box, which can quickly and selectively remove oil pollutants floating on water surface. Therefore, it can be expected that the as-prepared mesh with good superhydrophobicity and easy operated fabrication process may provide a candidate not only for gravity driven oil/water separation but also for designing many other oil collector.

Temperature-controlled 3-phase oil-water-oil continuous separation by PNIPAM-modified stainless steel mesh

In recent years, the frequent occurrence of oil spills has been a serious threat to marine and aquatic ecosystems. The environmental and economic demands also emphasize the need for materials which can effectively separate oil and water. In order to handle these environmental issues caused by oil spills, all kinds of oil-water separation methods have been developed. In this work, we have fabricated a thermosensitive device with a simple and versatile method: we sprayed the spray adhesive onto a stainless steel mesh box, then amino-P25 nanoparticles were sprayed onto the device directly. Finally, PNIPAM was synthesized on the surface of device. The wettability of PNIPAM modified separation device can be controlled by temperature and finally a 3-phase oil-water-oil continuous separation was realized.

Water flow buffers shifts in bacterial community structure in heat-stressed Acropora muricata

Deterioration of coral health and associated change in the coral holobiont’s bacterial community are often a result of different environmental stressors acting synergistically. There is evidence that water flow is important for a coral’s resistance to elevated seawater temperature, but there is no information on how water flow affects the coral-associated bacterial community under these conditions. In a laboratory cross-design experiment, Acropora muricata nubbins were subjected to interactive effects of seawater temperature (27 °C to 31 °C) and water flow (0.20 m s−1 and 0.03 m s−1). In an in situ experiment, water flow manipulation was conducted with three colonies of A. muricata during the winter and summer, by partially enclosing each colony in a clear plastic mesh box. 16S rRNA amplicon pyrosequencing showed an increase in the relative abundance of Flavobacteriales and Rhodobacterales in the laboratory experiment, and Vibrio spp. in the in situ experiment when corals were exposed to elevated temperature and slow water flow. In contrast, corals that were exposed to faster water flow under laboratory and in situ conditions had a stable bacterial community. These findings indicate that water flow plays an important role in the maintenance of specific coral-bacteria associations during times of elevated thermal stress.

Dehydration of Kiwifruit (Actinidia deliciosa) Slices Using Heat Pipe Combined with Impingement Technology

Abstract This study is designed to investigate drying kinetics, heating characteristics and energy consumption of heat pipe-impingement drying (HID) kiwifruit slices. Subsequently, color and rehydration characteristics of dried kiwifruit slices were also studied. The results showed that Modified Page model and trinomial regression equation provided appropriate fit for drying and heating curves of kiwifruit slices, respectively. In addition, the treatment for increasing drying temperatures and air velocities, and decreasing the distance between jet nozzles and material steel wire mesh box (DJM) was shown to enhance drying productivity. It was also found that low temperature, high air velocity and low DJM contributed to the processing of high-quality dried kiwifruit and the reduction of energy consumption. These results suggest that kiwifruit slices can be dried effectively with HID, and the predictive equations of heat and mass transfer could be applied to industrial design and operational guide for the HID of kiwifruit.

Green Approach to the Fabrication of Superhydrophobic Mesh Surface for Oil/Water Separation

We report a simple and environment friendly method to fabricate superhydrophobic metallic mesh surfaces for oil/water separation. The obtained mesh surface exhibits superhydrophobicity and superoleophilicity after it was dried in an oven at 200 °C for 10 min. A rough silver layer is formed on the mesh surface after immersion, and the spontaneous adsorption of airborne carbon contaminants on the silver surface lower the surface free energy of the mesh. No low-surface-energy reagents and/or volatile organic solvents are used. In addition, we demonstrate that by using the mesh box, oils can be separated and collected from the surface of water repeatedly, and that high separation efficiencies of larger than 92 % are retained for various oils. Moreover, the superhydrophobic mesh also possesses excellent corrosion resistance and thermal stability. Hence, these superhydrophobic meshes might be good candidates for the practical separation of oil from the surface of water.

A superhydrophobic and superoleophilic miniature mesh box for oil spill clean up

In this paper, we have fabricated a miniature mesh box (SS-MB) with surface superhydrophobicity and superoleophilicity for possible application in the field of oil spill clean up. The superhydrophobic SS-MB was fabricated by boiling a sheet of copper mesh in CuSO4 aqueous solution for an hour. The as-prepared SS-MB rapidly and selectively contained various industrial oils, with a high separation capacity, but did not adsorb any water due to its porosity, superoleophilicity and superhydrophobicity. Additionally, the oil contained by the SS-MB could be easily sucked out using a dropper, for reuse. After washing with toluene, the SS-MB could be used in the next oil–water separation cycle without losing its high separating ability even after 20 separation cycles. Furthermore, the SS-MB is stable under ambient conditions and also shows desirable corrosion resistance under conditions that mimic marine water. Therefore, the SS-MB has the advantages of easy fabrication, excellent oil–water separation and collection properties from the surface of the water, reusability, and reasonable stability under ambient and corrosive conditions, which make it suitable for the fast cleanup of oil spills.

Flexibility in food extraction techniques in urban free-ranging bonnet macaques, Macaca radiata.

Non-human primate populations, other than responding appropriately to naturally occurring challenges, also need to cope with anthropogenic factors such as environmental pollution, resource depletion, and habitat destruction. Populations and individuals are likely to show considerable variations in food extraction abilities, with some populations and individuals more efficient than others at exploiting a set of resources. In this study, we examined among urban free-ranging bonnet macaques, Macaca radiata (a) local differences in food extraction abilities, (b) between-individual variation and within-individual consistency in problem-solving success and the underlying problem-solving characteristics, and (c) behavioral patterns associated with higher efficiency in food extraction. When presented with novel food extraction tasks, the urban macaques having more frequent exposure to novel physical objects in their surroundings, extracted food material from PET bottles and also solved another food extraction task (i.e., extracting an orange from a wire mesh box), more often than those living under more natural conditions. Adults solved the tasks more frequently than juveniles, and females more frequently than males. Both solution-technique and problem-solving characteristics varied across individuals but remained consistent within each individual across the successive presentations of PET bottles. The macaques that solved the tasks showed lesser within-individual variation in their food extraction behavior as compared to those that failed to solve the tasks. A few macaques appropriately modified their problem-solving behavior in accordance with the task requirements and solved the modified versions of the tasks without trial-and-error learning. These observations are ecologically relevant – they demonstrate considerable local differences in food extraction abilities, between-individual variation and within-individual consistency in food extraction techniques among free-ranging bonnet macaques, possibly affecting the species’ local adaptability and resilience to environmental changes.

Effect of habitat structural complexity on collembolan communities

AbstractWe investigated soil microarthropod communities in two physically dissimilar inorganic soil materials and in a mixture of these two materials to examine the effect of the structural complexity of a habitat on microarthropod abundance and communities, teasing it out from that of nutritional factors. Mesh boxes were filled with perlite (a highly porous material), similar size of granite gravels (no pores inside), or their mixture, and placed on a forest floor. The boxes were collected after 8 or 20 months, and the microarthropods were extracted and identified to the species level, with a focus on Collembola. We also evaluated fine‐root biomass and the amount of organic matter in the boxes. It was found that the mixture of perlite and granite enhanced microarthropod abundance and root development. A partial redundancy analysis revealed that collembolan communities developed differently among the substrate materials. We also found that variation in the collembolan communities was related to fine‐root development and the abundance of other microarthropods, implying that habitat structural complexity affects collembolan communities indirectly by affecting soil food webs.

The virtual node polygonal element method for nonlinear thermal analysis with application to hybrid laser welding

The nonlinear heat transfer process occurring during hybrid laser welding was simulated using the Virtual-node Polygonal Element (VPE) method within the framework of the Finite Element Method (FEM). To achieve robustness in large-scale welding simulations, a dynamic mesh refinement with quadtree and octree data structures was used in the welding region. Accuracy, convergence and efficiency were verified by solving two and three dimensional problems. It is found that the present VPE can successfully simulate the hybrid laser welding process with good accuracy and convergence. The adaptive refined mesh box can synchronously move with the welding heat source, which dramatically reduces the number of field nodes. Compared with the standard FEM,the VPEM requires only approximately 42% of the total degrees of freedom used in standard FEM for the same accuracy. Furthermore, we compare the computational cost and accuracy of the method to that of the finite element method, the edge based virtual node polygonal element/virtual node method, the edge-based Smoothed Point Interpolation Meshless Method (ES-PIM), the edge-based Element (ES-PIM) the Element Free Galerkin (EFG) method and the Meshless Local Petrove-Galerkin Petrov–Galerkin (MLPG) method. Compared to all those methods, the proposed scheme is found competitive in terms of computational cost versus accuracy, and benefit from a simple implementation.

The experimental hut: hosting vectors

In southeast Tanzania, ten canvas huts raised on wooden foundations occupy a plot of cleared rice field. Designed to simulate malaria transmission on the domestic scale, the experimental hut is constructed in the fashion of indigenous homes (complete with villagers, paid to spend the night), but is structurally modified to render mosquito behaviours visible. The experiment's domestic camouflage provides the setting for multiple, and reciprocal, hostings: between parasite, mosquito, and human, and between villagers, volunteers, and scientists. This paper explores the valences of hospitality when the ‘home’ becomes a site of experimentation, and the cosmopolitan encounters these experiments entail.RésuméDans le sud‐est de la Tanzanie, dix cases en toile dressées sur des fondations en bois occupent une parcelle de rizière dégagée. Conçue pour simuler la transmission du paludisme à l'échelle domestique, la case expérimentale est construite à la manière des maisons indigènes (avec même des villageois, payés pour y passer la nuit), mais sa structure est modifiée de façon à rendre le comportement des moustiques visible. Le camouflage domestique de l'expérience crée le cadre de multiples hébergements réciproques : entre le parasite, le moustique et l'homme, entre villageois, bénévoles et scientifiques. Le présent article explore les valences de l'hospitalité quand « la maison » devient un lieu d'expérimentation, ainsi que les rencontres cosmopolites qu'impliquent ces expériences.