Cover Material Research Articles

Evolution of solidified municipal sludge used as landfill cover material under wet–dry cycles: mechanical characteristics, microstructural, and seepage properties

Evolution of solidified municipal sludge used as landfill cover material under wet–dry cycles: mechanical characteristics, microstructural, and seepage properties

Potential Effects of Soccer Ball Characteristics on Ball-to-Head Contact: A Systematic Review

Background: The aim of this study was to systematically review research on the effect of soccer ball characteristics on ball-to-head contact. Methods: This systematic review was conducted using electronic databases, which included PubMed, Cochrane, and Web of Science. The search strategy combined keywords related to soccer, the ball and its characteristics, heading, and kinematics variables. Studies analyzing the impact of soccer ball characteristics on heading biomechanics were included. The review included studies using mathematical models, simulations, and human subjects. Results: A total of nine studies were included, highlighting the lack of evidence on this topic. The following ball characteristics were investigated: inflation pressure (n = 7), mass (n = 4), structure/material properties (n = 3), size/diameter (n = 3), and stiffness (n = 3). Most studies used non-human subjects, such as mathematical, simulated, or head-form models. Key findings were as follows: (a) reducing inflation pressure may decrease impact magnitude; (b) ball size may not directly relate to impact magnitude, but one study found that a smaller size resulted in a shorter impact time; (c) lower impact observed with decreasing ball mass; (d) lowering stiffness showed a tendency to lower impact; (e) two studies on water absorption found that wet balls were heavier and had greater impact forces than dry balls; and (f) ball structure and cover material directly influenced impulsive forces. Conclusions: Modifying soccer ball characteristics may reduce heading forces, but the available research has limitations. More controlled studies are needed to determine optimal ball properties for mitigating injury risk during soccer heading. Standardized testing methods can further clarify the biomechanics of heading, supporting ongoing innovations to enhance player experience.

Optimizing damage resistance and structural evolution in CaO-modified Li2O-Al2O3-B2O3-TiO2-P2O5 glass-ceramics

Aluminoborate glass, recognized for its remarkable crack resistance, presents significant potential as a cover material for portable electronic devices. Nevertheless, its relatively low hardness has been a limiting factor. This study synthesized a series of 11 Li2O-30 Al2O3-(55-x) B2O3-2 TiO2-2 P2O5-xCaO (wt%), with x varying from 0 to 10, employing the melt-cast method. The resultant glass-ceramics were produced via heat treatment at 590 °C for 2 h, followed by a systematic examination of their structural and mechanical properties. The investigation demonstrated that an increase in CaO content diminishes crystallization and induces a morphological transition in the crystalline phases from granular and short rod-like structures to lath-like formations, which subsequently impacts the coordination environment of Al and B atoms. With a CaO content of 2 %, the GC2 sample precipitated Li(Al7B4O17) and Li2AlB5O10 phases, achieving a compressive strength (CR) value of 15.0 N, a hardness of 7.51 GPa, and a fracture toughness of 1.50 MPa m0.5. This glass-ceramic exhibited optimal scratch resistance and visible light transmittance exceeding 85 %, underscoring its considerable promise for application as smartphone cover glass due to its impressive overall damage resistance.

Experimental study on condensation-free radiant cooling panel with low-temperature for local cooling in vehicles - Part 1: Design process and feasibility evaluation with performance test

Although radiant cooling has significant advantages (high efficiency and thermal comfort), insufficient cooling capacity and condensation risk limit the practical application. In this study, a novel condensation-free radiant cooling panel (RCP) with high cooling capacity is proposed. The performance of proposed RCP was experimentally evaluated at different operating conditions. The transparent cover and surface-painting spray materials of the RCP were examined using Fourier-transform infrared spectroscopy to analyze their transmittance and absorptivity. The total cooling heat flux of the proposed RCP ranged between 2019.5 and 3824.5 W m–2, which are significantly higher than those of previous studies (70–1457 W m–2), owing to low surface temperatures. The radiant heat flux decreased by 13.5% when the distance between the cooling surface and the heater increased from 10 cm to 20 cm, and decreased by 52% when evaporating temperature increased from –40 °C to –20 °C. However, the heater and ambient temperatures showed insignificant effect. The results of this study report feasibility of the proposed RCP and parameters that influence performance. The target application of the proposed RCP is local cooling systems in vehicles to enhance thermal comfort, which is given in succeeding research, Part 2: Demonstration with passengers for thermal comfort analysis.

Evaluation of the impact of land use ratios and cover materials in settlement design on stormwater runoff

Due to higher levels of urbanization and increasing impermeable hard land covers, green spaces are decreasing, resulting in stormwater loss as surface runoff instead of being absorbed by soil and reintroduced into the water cycle. This study investigates the effect of land use ratios and land cover materials resulting from settlement design on surface runoff volume. The study was conducted using various scenarios in 9 settlements with different land use ratios, including roofs, sidewalks, parking areas, roadways, and green areas in Istanbul, a city with a high urbanization rate. Thus, surface runoff volume in settlements depending on the land use ratios was evaluated. A total of 336 material combinations were developed using various material alternatives in addition to different land use ratios. Therefore, the effect of different land cover materials used in the settlements on surface runoff volume was also evaluated. Study requirements were taken into consideration when choosing the calculation method, and the Rational Method, often preferred for calculating surface runoff volumes in small urban basins, was chosen. According to the calculation results obtained from the settlements developed for this study, surface runoff volume can be reduced by 37.10 % by increasing only the green space ratio and by 67.65 % by using different material alternatives in the same settlement. Additionally, it was observed that each improvement made to reduce surface runoff in settlements resulted in a positive change.

Building Roof Covering Materials for Residential and Commercial: Comparison and Best Choices

Choosing the right roofing material is an important aspect of building design and construction. Both residential and commercial buildings have roof-related needs. But basically, the selection of roofing materials is not only for protection from but also based on energy efficiency, aesthetics, and longevity of the building. In addition, the design of roof shape selection must be done carefully because the wrong selection can cause rainwater seepage or leakage on the roof and high repair costs. This research aims to explore by comparing the characteristics of roof covering materials and provide the best choice based on needs. The research method used is a qualitative research method with the stages carried out, namely data collection techniques, sample determination, data analysis and research conclusions. Based on the analysis, it is concluded that for residential houses, tile roofs and concrete deck roofs are the best choice because they offer an optimal combination of aesthetics, durability, energy efficiency, and cost that is suitable for the Indonesian climate. While for commercial buildings, metal tile roof is an excellent choice due to its durability, energy efficiency, and modern aesthetics that suit the needs of commercial buildings.

Mechanical and degradation properties of degradable cover materials for sugarcane leaves

Mulch was prepared using composted sugarcane leaves, with polyvinyl alcohol and cationic starch as adhesives, through compression molding. The study aimed to investigate the effects of different adhesives on the mechanical properties, thermal oxidative degradation performance, and biodegradability of the covering materials. The results indicated that, when the adhesive dosage was consistent, cover material A, which utilized polyvinyl alcohol as the adhesive, exhibited higher tensile strength and elongation at break compared to cover material B, which employed a blend of polyvinyl alcohol and cationic starch. Specifically, at an adhesive dosage of 20%, cover material A achieved a tensile strength of 0.46 MPa and an elongation at break of 7.72%, representing the highest values among all experimental groups. There was minimal disparity in the thermal oxidative degradation performance between materials prepared with either adhesive; however, a higher quantity of adhesive led to decreased biodegradability performance. After being buried in soil for 120 days, the degradation exceeded 40% for both materials, resulting in loss of their original shape and strength properties. In conclusion, while sugarcane leaves-based biodegradable materials demonstrate favorable degradation performance, further enhancements are necessary to improve their mechanical properties. These materials have potential applications as substitutes for plastic mulch.

The effect of boron anomaly on the dielectric properties and thermal expansion of barium borosilicate glasses for 3D packaging systems

Barium borosilicate (BBS) glass is a potential three-dimensional system packaging and sensor cover material. In this study, we prepared glass samples with different SiO2/B2O3 ratios based on the revised model of Dell and Bray and discussed the effect of boron anomaly on dielectric and thermal properties through Raman spectroscopy. The results indicate that the [BO4] tetrahedrons are beneficial in reducing the dielectric constant and dielectric loss to a certain extent, while the improvement in the coefficient of thermal expansion (CTE) is attributed to the depolymerization of the glass network by the [BO3] triangles. After the disappearance of the boron anomaly, a certain amount of dielectric performance is sacrificed in exchange for an increase in the CTE. When the substitution rate of B2O3 for SiO2 reaches 15.12 mol%, the CTE of the sample increases to 8.43 × 10−6/°C, in addition, the dielectric constant and dielectric loss decrease to 4.90 and 0.0071 (@1 GHz), respectively. In summary, this work provides a suitable method for preparing glass with a high coefficient of expansion and low dielectric loss to address the thermal mismatch effect of different materials in electronic packaging systems.

Enhanced microbial remediation of uranium tailings through red soil utilization

Seepage of uranium tailings has become a focus of attention in the uranium mining and metallurgy industry, and in-situ microbial remediation is considered an effective way to treat uranium pollution. However, this method has the drawbacks of easy biomass loss and unstable remediation effect. To overcome these issues, spare red soil around the uranium mine was used to enhance the efficiency and stability of bioremediation. Furthermore, the bioremediation mechanism was revealed by employing XRD, FTIR, XPS, and 16S rRNA. The results showed that red soil, as a barrier material, had the adsorption potential of 8.21–148.00 mg U/kg soil, but the adsorption is accompanied by the release of certain acidic and oxidative substances. During the dynamic microbial remediation, red soil was used as a cover material to neutralize acidity, provide a higher reduction potential (<-200 mV), and increase the retention rate of microbial agent (19.06 mL/d) compared to the remediation group without red soil. In the presence of red soil, the anaerobic system could maintain the uranium concentration in the solution below 0.3 mg/L for more than 70 days. Moreover, the generation of new clay minerals driven by microorganisms was more conducive to the stability of uranium tailings. Through alcohol and amino acid metabolism of microorganisms, a reducing environment with reduced valence states of multiple elements (such as S2−, Fe2+, and U4+) was formed. At the same time, the relative abundance of functional microbial communities in uranium tailings improved in presence of red soil and Desulfovirobo, Desulfocapsa, Desulfosporosinus, and other active microbial communities reconstructed the anaerobic environment. The study provides a new two-in-one solution for treatment of uranium tailings and resource utilization of red soil through in-situ microbial remediation.

What controls river widening? Comparing large and extreme flood events

AbstractExtreme (i.e., centennial‐scale) floods are by definition rare and can therefore be difficult to study. As a result, case studies of response to extreme floods can provide unique insights. On 15 November 2021, the Nicola River in British Columbia, Canada, experienced a 200‐year flood that increased the average width of the Nicola River by more than 50% (35 m), leaving the only highway in the region impassable for nearly 12 months. This research assesses the spatial variability of erosion along a 71‐km‐long segment of the Nicola River during a period with a large flood (2015–2018) and a second period containing the extreme flood in 2021 (2018–2021). We use a random forest statistical analysis to explore the most important valley and channel characteristics affecting relative widening during both periods. Unit stream power, gradient and valley confinement were the primary determinants of erosion during the extreme flood, whereas vegetation cover, channel pattern and surficial material were less important. Erosion during the large flood event was not related to these variables, with channel pattern providing a better indication of widening potential. As the Nicola River is flanked by erodible glacial deposits, this work provides important insight into river response in the paraglacial environments that are common throughout much of Canada and the northern United States, as well as Europe and Asia, but less intensely studied. In these settings, the geomorphic response to large floods may not be representative of the potential erosion (and infrastructure impacts) that can occur during extreme events, which destabilize glacial terraces in confined reaches. Historical observations should therefore be used with caution in paraglacial settings as extreme events may not be captured in available data, creating a perception of stability in confined reaches that may have the potential to erode dramatically during extreme events.

Case study: reducing heating energy consumption in a high tunnel greenhouse with renewable energy and microclimate control by bench-top root-zone heating, bench covers, and under-bench insulation

Appalachian State University's Nexus project designed an efficient greenhouse heating system that integrated renewable energy and root zone heating technology to reduce the greenhouse heating energy burden on local farmers and installed it at local cooperative farms. This study analyzed 5 years of data from 2018 to 2022 to investigate the energy savings and microclimate control effectiveness of the Nexus heating system installed at Springhouse Farm in North Carolina, USA. By varying bench cover materials, bottom insulation, and the number of loops of root zone tubing, the different soil temperatures required for plant types and growth stages were achieved with a single temperature controller. A root zone heating fluid of 32.2 ℃ satisfactorily maintained the germination soil between 20 and 25 ℃ in March 2019 with an average outside temperature of 4.8 ℃ and an average low temperature of − 0.4 ℃. Growing soil maintained an average temperature of 15 ℃ with bottom insulation and an average of 11–12 ℃ without bottom insulation. Compared to the conventional heating system (a forced-air propane unit heater alone), weather-adjusted propane consumption (propane usage divided by heating degree days) was reduced by 65% with the Nexus system alone and 45% with the Nexus system and unit heater together. It shows that the Nexus system has significantly reduced greenhouse heating energy consumption and maintained productive conditions. The renewable energy fraction ranged only 9–13% of the total thermal energy used due to the high inlet temperature entering the solar thermal collector. This can be improved by separating the heat storage and backup heat source.

Experimental investigation of bond behavior with lap splice for CFRP-steel composite bars in coral sea-sand aggregate seawater concrete

The pull-out tests on a total of 81 lap-spliced specimens in 27 groups were conducted to investigate the lap-spliced behavior and the appropriate splice length for CFRP-steel composite bars (C-FSCB) in coral sea-sand aggregate seawater concrete (CSSC). The test variables included the C-FSCB diameter (dc), splice length, concrete cover thickness, concrete strength, lap spacing, stirrup ratio, and materials type. Then, the influence of various test variables on the lap-spliced behavior of C-FSCB in CSSC was analyzed. The results showed that when the splice length was less than 17dc, the specimens exhibited pull-out and concrete splitting failure, while C-FSCB fracture failure occurred when the splice length exceeded 17dc. Severe shear damage was observed on the C-FSCB surface in the case of pull-out and concrete splitting failure. When the splice length was less than 14dc, the bond strength of the specimens was approximately 7.2 MPa. As the splice length increased beyond 14dc, the bond strength gradually decreased. After the cover thickness was greater than 4dc or the compressive strength of CSSC was greater than 30 MPa, the variation in bond strength of the specimens can be negligible. Increasing the stirrup ratio led to an increase in bond strength and a significant reduction in crack width. Compared to specimens with steel bars, the bond strength reduction for specimens with C-FSCB exceeded 25%. Based on the test results, calculation formulas for the bond strength and splice length of C-FSCB in CSSC were established. Furthermore, referring to the approach in the Chinese code GB 50010–2010, a simplified calculation formula for splice length was proposed.

A Study on the Post-treatments of Citrus Pomace-based Soil Covering Materials for Improving Functional Properties

A Study on the Post-treatments of Citrus Pomace-based Soil Covering Materials for Improving Functional Properties

Acclimatization and Foraging of Native Brazilian Stingless Bees in Arenas with Covering Materials of Different Spectral Properties.

The use of Meliponini for crop pollination in protected environments is practically non-existent. One of the reasons is the difficulty of acclimatizing Meliponini to the temperature and light conditions inside greenhouses. We investigated how covering materials used in greenhouses, which filter different intensities of ultraviolet (UV) light, affect the foraging behaviors, flight orientation, attraction to walls and ceilings, and mortality of Scaptotrigona cf. postica (Letreille), Frieseomelitta varia (Lepeletier), and Melipona quadrifasciata (Lepeletier). The experiments were conducted in 5.3 m3 arenas covered with four types of plastic films that do not polarize sunlight, with UV transmittance levels ranging from 0.1 to 54%, compared to a transparent glass control. The temperature inside the arenas varied between treatments, from 27 ± 3°C to 31 ± 2°C. All three species collected resources and returned to the colony, regardless of the covering material. However, the proportion of this behavior, the number of bees attracted to the ceiling and wall, and mortality varied among treatments and/or throughout the confinement days for each species. Melipona quadrifasciata and F. varia acclimatized better to the confined environments than S. cf. postica and showed consistent resource collection behavior throughout the confinement days in all tested materials, except for the one that filtered around 90% of UV. In all three species, the mortality gradually decreased throughout the confinement days. The results indicate that the choice of covering material, considering its optical characteristics, can be crucial to ensure greater effectiveness of the pollination services provided by stingless bees in protected systems.

Use of polymer dispersed liquid crystal (PDLC) film as a greenhouse cover material

Use of polymer dispersed liquid crystal (PDLC) film as a greenhouse cover material

Considerations on the Failure Mechanisms at Fatigue Loading of 1018 Steel Samples Coated with Wip-C1 by Cold Spray.

There are some important advantages presented by metal specimens coated with WIP-C1 (Ni/CrC)-type materials. However, given the coating methods and the stress under dynamic loads, there are issues that need to be taken into account, particularly in terms of the behavior at the interface between the two materials. Using standardized cylindrical 1018 steel specimens uniformly coated with WIP-C1 (Ni/CrC) by cold spraying, this study investigated the fatigue behavior of the specimen as a whole, focusing on the interface areas of the two materials. The fatigue life diagram is given, to a large extent, by the behavior of the base material. As a result, in this work, we have focused not so much on the fatigue behavior of the assembly as on the integrity of the coating material and the defects, failures, etc., that may occur at the interface after a certain number of cycles. The applied load was cyclic fatigue through alternating-symmetric cycles. Scanning optical microscopy was used to observe plastic deformations and crack propagation during the breakage process. It was found that both the base material zone and the cover material zone presented good performance when the maximum stresses were at low values. A fatigue durability curve was also plotted, showing a conventional appearance for a metallic material, slightly influenced by the destruction of the base material interface. At higher maximum stress and, consequently, to large strains, a series of destructions at the interface of the two materials, of different types, were observed and will be highlighted in the paper.

Pemanfaatan Limbah Cangkang Kerang sebagai Bahan Campuran dalam Pembuatan Paving Block (Literature Review)

Various innovations in making paving blocks are made to meet development needs. Where the advantages of paving blocks include easy maintenance, faster implementation time, and easy installation. Paving block is a composition of building materials made from a mixture of Portland cement, fine aggregate, and water. Paving block is one of the building materials that is in great demand by the public as a ground cover material, in addition to cement, asphalt, and concrete which is usually applied to parking lots, parks, school yards, and so on according to the needs of its users. The writing of this article, has the aim of reviewing the results of previous research in the form of compressive test results on the utilization of shell waste in the manufacture of innovative materials in the form of paving blocks, therefore the research method in this article is literature review, literature review does not only mean reading literature, but more towards an in-depth and critical evaluation of previous research on a topic.

Investigation of Two New Grafting Techniques for Dorsal Augmentation Rhinoplasty: An Experimental Study with New Zealand White Rabbits.

Cartilage is an important source in supporting the structure of the nose for dorsal augmentation rhinoplasty. However, it is known that its viability is not always on the ideal level. Various wrapping materials are used to increase the strength of cartilage. Donor site morbidity, which develops following the harvesting of both cartilage and fascia as one such cover material, has attracted interest in recent years. In this study, we aimed to investigate the potential of dermis and tendon autografts as alternatives to fascia and cartilage. The sample of the study included 16 New Zealand white rabbits. The right auricular cartilage of all rabbits was amputated, and it was transformed into diced cartilage autografts. The dermis autografts from the right gluteal areas of the rabbits were deepithelialized, and lumbosacral fascia autografts were harvested from the same incision. Additionally, the Achilles tendon of each rabbit was harvested and transformed into diced tendon autografts. Four different autografts were embedded under the skin of each rabbit from 4 different pouches opened in the back of the rabbit. These autografts included diced cartilage alone (Intervention 1), fascia-wrapped cartilage (Intervention 2), dermis-wrapped cartilage (Intervention 3) and fascia-wrapped tendon (Intervention 4) autografts. Intervention 1 had the most irregular appearance, the outcomes in Intervention 4 were volumetrically smaller and softer. Connective tissue formed between the diced pieces in all interventions, and it was observed that the dermis and fascia had a capsule-like appearance, and their viability was preserved. The differences between the initial and final measurements of the volumes of interventions 1, 2 and 3 were statistically significant (p<0.05). There was no significant difference between the initial and final volumetric measurements of intervention 4 (p>0.05). More peripheral proliferation was observed in the interventions of fascia-wrapped and dermis-wrapped diced cartilage compared to the other interventions. The intervention including fascia-wrapped diced tendon grafts had displayed more fibrosis, fragmentation and collagen fibers, while it showed a lower amount of elastic fiber. There were no significant differences among the intervention in terms of other histological parameters. Tendon autografts may be a good option for dorsal augmentation rhinoplasty as they are easily harvested and have minimal donor site morbidity. Dermis autograft usage is more advantageous than fascia usage in terms of accessibility and convenience. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A New Classification Rule-Set for Mapping Surface Water in Complex Topographical Regions Using Sentinel-2 Imagery

Surface water is a critical natural resource, but its mapping accuracy is vulnerable to cloud cover, snow, shadows, and diverse roofing materials. Recognizing the limitations of a single threshold segmentation method that fails to achieve high-precision extraction of surface water in complex terrain areas, this study introduces a multiple threshold water detection rule (MTWDR) method to improve water extraction results. This method uses the multi-band reflectance characteristics of ground features to construct a water index and combines brightness features with the Otsu algorithm to eliminate interference from highly reflective ground features like ice, snow, bright material buildings, and clouds. The Yunan–Guizhou Plateau was selected as the study area due to its complex terrain and multiple types of surface water, and experiments were conducted using Sentinel-2 data on the Google Earth Engine (GEE). The results demonstrate that: (1) The proposed method achieves an overall accuracy of 94.08% and a kappa coefficient of 0.8831 in mountainous areas. In urban areas, the overall accuracy reaches 95.15%, accompanied by a kappa coefficient of 0.8945. (2) Compared to five widely used water indexes and rules, the MTWDR method improves accuracy by more than 3%. (3) It effectively overcomes interference from highly reflective ground features while maintaining the integrity and accuracy of water boundary extraction. In conclusion, the proposed method enhances extraction accuracy across different types of surface water within complex terrain areas, and can provide significant theoretical implications and practical value for researching and applying surface water resources.

Recovery of aluminum oxide and iron oxide from aluminum electrolysis iron-rich cover material and preparation of aluminum fluoride.

In aluminum electrolysis, the iron-rich cover material is formed on the cover material and the steel rod connecting the carbon anode. Due to the high iron content in the iron-rich cover material, it differs from traditional cover material and thus requires harmless recycling and treatment. A process was proposed and used in this study to recovery F, Al, and Fe elements from the iron-rich cover material. This process involved aluminum sulfate solution leaching for fluorine recovery and alkali-acid synergistic leaching for α-Al2O3 and Fe2O3 recovery were obtained. The optimal leaching rates for F, Na, Ca, Fe, and Si were 93.92, 96.25, 94.53, 4.48, and 28.87%, respectively. The leaching solution and leaching residue were obtained. The leaching solution was neutralized to obtain the aluminum hydroxide fluoride hydrate (AHFH, AlF1.5(OH)1.5·(H2O)0.375). AHFH was calcined to form a mixture of AlF3 and Al2O3 with a purity of 96.14%. The overall recovery rate of F in the entire process was 92.36%. Additionally, the leaching residue was sequentially leached with alkali and acid to obtain the acid leach residue α-Al2O3. The pH of the acid-leached solution was adjusted to produce a black-brown precipitate, which was converted to Fe2O3 under a high-temperature calcination, and the recovery rate of Fe in the whole process was 94.54%. Therefore, this study provides a new method for recovering F, Al, and Fe in iron-rich cover material, enabling the utilization of aluminum hazardous waste sources.