Rubber Sheet Research Articles

Analysis of Maintenance Methods and Process Improvement of Vacuum Laser Collimation System for Dams

The method and process of vacuum laser collimation system maintenance is one of the key technologies directly related to the accuracy of dam vacuum laser collimation system measurement value. Taking the maintenance methods and processes of vacuum laser collimation system in Lianlu and Xiacheng as the background, a new set of dam vacuum laser collimation system maintenance methods and processes are proposed, aiming to make up for the gaps in the maintenance of vacuum laser collimation system. It was found that the vacuum pipeline operates at vacuum values between 400 Pa and 900 Pa. The influence of light on the vacuum laser is avoided by correcting the system and shading the transmitting end as well as the connecting part of the receiving end and the vacuum pipeline with a rubber sheet. This new maintenance method and process also provides a useful reference for the safety monitoring of similar projects.

Effects of molecular interactions on the release of small molecules from silicone rubber

AbstractSilicone rubber is a good candidate as a carrier of small molecules in such applications as drug, fragrance and semiochemical delivery. When one matrix is loaded, the molecular interactions between the molecules and the matrix may affect their release rates. For this reason, it is important to investigate the effects of molecular interactions on release to better develop delivery systems with desirable release rates. In this study, the mass transfer and diffusion coefficients of three model molecules (i.e., octanol, octyl acetate, and octyl butyrate) were determined by monitoring their release from silicone rubber sheets loaded using headspace gas chromatography–mass spectrometry. Differential scanning calorimetry was used to characterize the plasticizing effects and Fourier transform infrared spectroscopy was used to characterize the molecular interactions. It was found that the release of octanol conformed to the Fickian diffusion pattern at 1 wt% initial concentration but deviated as the concentration increased due to hydrogen bonding between octanol and the silanol group of the silica filler. When two small molecules were released simultaneously, the effects of one molecule on the diffusion coefficient of the other differed, a result explained by the competing effects of plasticizing and hydrogen bonding.

Remanufactured waste tire by-product valorization: Quantitative–qualitative sustainability-based assessment

Automotive tires are a major waste stream and there are currently numerous options for reusing, recycling, and remanufacturing the waste tire rubber (WTR) and other components. Some competing technologies (retreading, product repurposing, energy recovery, pyrolysis oil, waste-tire crumbing, and devulcanized rubber) are discussed here to demonstrate the broad scope of possible applications and identify the advantages/disadvantages of the processes. Based on the industrial maturity of the processes, this study performed a qualitative–quantitative fuzzy analysis of twelve alternative by-products of WTR, including 1) devulcanized or desulfurized rubber; 2) tiles, mats, and rod barriers; 3) composite materials; 4) bitumen; 5) asphalt; 6) heat energy; 7) crude oil; 8) diesel; 9) char and carbon black; 10) gasification gas; 11) activated adsorption carbon; and 12) lightweight concrete. Quantitative sustainability considerations were applied to weight the technical, economic, environmental, and social sustainability factors according to their importance, while qualitative factors were applied to weight the sustainability criteria of productivity, reliability, efficiency, waste tire size range, remanufacturing time, remanufacturing cost, ergonomics, human development, and employment potential based on insights from the published literature. Comparative literature-based statistical analysis of potential tire resources and conventional waste-tire recycling was performed. The results identified remanufacturing of WTR into devulcanized rubber sheets as the best sustainable business option with the highest sustainability index of 0.628, while lightweight concrete was the worst by-product option with a low sustainability index of 0.012. Other very-high-potential options include producing value-added rubber products and composite materials from the devulcanized rubber. These findings provide valuable insights for stakeholders in the field of waste-tire management and small-to-medium businesses looking to add further value to their WTR products. Furthermore, these findings could guide international research to help focus on the most sustainable use of WTR.

Energy and exergy analysis for fast drying of ribbed smoked sheets in a novel forced-convection rubber smoking room

Rubber sheet smoking rooms are widely used by small farmers in rubber growing regions: sheets of raw rubber latex are ‘smoked’ in them to remove moisture, preserve and prepare the rubber for transport. Energy and exergy for a novel forced-convection rubber sheet smoking room were analyzed. Inlet hot air velocity varied between 12 and 14 m/s and the fuel-wood moisture content was between 24–55 % dry basis. Thermal efficiency for drying ribbed smoked sheet (RSS) rubber was 13.4–16.7 %. The specific energy consumption (SEC) was between 13.5–16.9 MJ/kg of water evaporated. The highest thermal efficiency or lowest specific energy consumption was achieved when using the dry fuel-wood (inlet velocity 14 m/s, 53 % db fuel-wood), while the RSS quality was maximum (100 %). The overall second law (exergy) efficiency was from 2.2-5.8 %. The highest exergy efficiency was obtained for air at 12 m/s and 24 % db fuel-wood. However, in this condition, only 55 % of sheets showed good quality. The exergy efficiency for the most suitable condition (100 % high quality sheets) was 2.6 %. Compared to an earlier forced-convection smoking room, the new room reduced the drying time from 48 h to 36 h, while thermal efficiency increased from 14.3 % to 16.5 %. When compared to the original smoking room, 65 % fuel-wood and 50 % drying time were saved and the rubber sheet quality increased from ∼90 % to 100 %. Overall, our forced-convection room was more efficient, dried faster and produced better quality than all previous types.

Exploring the impact of polyvinylidenefluoride membrane physical properties on the enrichment efficacy of microfluidic electro-membrane extraction of acidic drugs

Membrane technology has revolutionized various fields with its energy efficiency, versatility, user-friendliness, and adaptability. This study introduces a microfluidic chip, comprised of silicone rubber and polymethylmethacrylate (PMMA) sheets to explore the impacts of polymeric support morphology on electro-membrane extraction efficiency, representing a pioneering exploration in this field. In this research, three polyvinylidenefluoride (PVDF) membranes with distinct pore sizes were fabricated and their characteristics were assessed through field-emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM). This investigation centers on the extraction of three widely prescribed non-steroidal anti-inflammatory drugs: aspirin (ASA), naproxen (NAP), and ibuprofen (IBU). Quantitative parameters in the extraction process including voltage, donor phase flow rate, and acceptor phase composition were optimized, considering the type of membrane as a qualitative factor. To assess the performance of the fabricated PVDF membranes, a comparative analysis with a commercially available Polypropylene (PP) membrane was conducted. Efficient enrichment factors of 30.86, 23.15, and 21.06 were attained for ASA, NAP, and IBU, respectively, from urine samples under optimal conditions using the optimum PVDF membrane. Significantly, the choice of the ideal membrane amplified the purification levels of ASA, NAP, and IBU by factors of 1.6, 7.5, and 40, respectively.

Growth and Challenges of Rubber Plantation in North-Eastern States of India

The paper discussed the growth and challenges of rubber plantation in north-eastern states of India. It has been found that there are bright prospects of rubber plantation in the region. Rubber plants were first planted in 1950 in Assam. It helps in changing livelihoods of the tribal communities. Karimkhanj, Karbi Anglong, Kamrup and Goalpara districts are leading in rubber plantation. Rubber plantation is popular among the tribes in the East, West, North and South Garo Hills in Meghalaya. Peren, Mokokchung, Wokha, and Dimapur districts are popular for rubber plantation in Nagaland. Tuensang, Zunheboto, Mon, and Longleng are other districts have more potentiality for such plantation. Rubber board was introduced rubber plantation in Arunachal Pradesh in 1980s. The first rubber tree was planted in Tripura by Forest Department of Tripura in 1963. Tripura and Assam are far ahead then the other states of the region. This region is considered as non-traditional rubber plantation. Rubber plantation have positive impact on the financial status of the cultivators. Lack of skill workers, low price of rubber sheet, low quality of the rubber sheet, shortage of government subsidies, lack of support from the government agencies, and shortage of modern technologies are the basic challenges before the rubber cultivators.

Non-Fourier Heat Flux Model for the Magnetohydrodynamic Casson Nanofluid Flow Past a Porous Stretching Sheet using the Akbari-Gangi Method

The Casson fluid flow with porous material in magnetohydrodynamics is examined in this work. Additional semi-analytical results are investigated using the Silver-Water nanofluid. The Akbari-Ganji Method (AGM) is used to solve the semi-analytical Cattaneo-Christov heat flux model after taking thermal radiation into account. With the use of appropriate parameters, such as the relaxation time parameter, Prandtl number, radiation parameter, magnetic parameter, and so on, the normalized shear stress at the wall, temperature profile, and rate of heat flux may be examined. This issue has numerous industrial applications and technical procedures, such as the extrusion of rubber sheets and the manufacture of glass fiber. The main physical application is the discovery that a rise in the thermal relaxation parameter and Prandtl number maintains a constant fluid temperature.

Quantitative sustainability assessment of plant layouts for mechano-chemical remanufacturing of waste tires into rubber sheets with integrated pyrolysis-distillation

Waste tires are a major contributor to the solid waste stream globally. However, waste tires can be recovered and remanufactured into valuable products, such as rubber sheet, steel, and nylon. This study proposes a novel strategy of incorporating pyrolysis–distillation (P–R) lines into remanufacturing plant layouts for the mechano-chemical remanufacturing of waste tires into sheet rubber to add energy products as an additional output to diversify the profitable product range. A quantitative sustainability assessment was performed to evaluate batch, semi-continuous, and fully continuous P–R reactors with capacities of 5–50 t/day for pyrolysis and 5–20 t/day for distillation, which are integrated to develop 99 pre-design options to remanufacture 15–50 t/day of waste tires into energy products. The pre-designs were optimized quantitatively and reduced into eight alternatives for introduction at specific positions in the plant layouts to increase the capacity of the plant by approximately 40% (to process an extra 180 t/day of waste tires) based on European Union experience in producing energy products from waste tires. Accordingly, yields of energy products of 84,768 L/day of diesel, 63 t/day of charcoal, 27 t/day of waste steel, and 8.1 t/day of raw asphalt.can be obtained, thereby yielding 13.734–34.219 million USD/year profit. Furthermore, a high technical feasibility index of 0.82, very high economic sustainability satisfaction factor of 0.98, very high environmental sustainability satisfaction factor of 0.97, and very high social sustainability satisfaction factor of 0.91 indicate that the proposed remanufacturing process is viable as a quadilateral-bottom-line sustainability strategy.

Direct, model-free acoustic evaluation of stresses and strains in loaded nonlinear soft solids

We show analytically and experimentally that the states of stress and strain existing in a mechanically loaded elastic material can be accessed directly from elastic wave speed measurements, without having to determine, or even know, its material linear and nonlinear elastic parameters. These techniques are expected to have important applications in the health monitoring of loaded structures. Examples include stressed hydrogels, muscles, and thin membranes, such as a stretched rubber sheet, a piece of cling film (∼10 μm thick), and the animal skin of a bodhrán, a traditional Irish drum.

Modelling gravitational-wave emission and detection on spandex using a high-speed camera

This paper demonstrates a variation of the rubber sheet experiment (Gravitational Waves Work Like This Drill on Spandex) for measuring the properties of modelled gravitational waves. Mechanically induced waves on the rubber sheet are observed by a high-speed camera and the slow-motion videos are analysed with the Tracker program. We describe the theoretical background and the execution of the measurement process. The measured displacements are suitable for modelling real gravitational-wave signals and determinating properties of the sources.

Piezoelectric rubber sheet sensor: a promising tool for home sleep apnea testing

PurposeThis study aimed to develop an unobtrusive method for home sleep apnea testing (HSAT) utilizing micromotion signals obtained by a piezoelectric rubber sheet sensor.MethodsAlgorithms were designated to extract respiratory and ballistocardiogram components from micromotion signals and to detect respiratory events as the characteristic separation of the fast envelope of the respiration component from the slow envelope. In 78 adults with diagnosed or suspected sleep apnea, micromotion signal was recorded with a piezoelectric rubber sheet sensor placed beneath the bedsheet during polysomnography. In a half of the subjects, the algorithms were optimized to calculate respiratory event index (REI), estimating apnea–hypopnea index (AHI). In the other half of subjects, the performance of REI in classifying sleep apnea severity was evaluated. Additionally, the predictive value of the frequency of cyclic variation in heart rate (Fcv) obtained from the ballistocardiogram was assessed.ResultsIn the training group, the optimized REI showed a strong correlation with the AHI (r = 0.93). Using the optimal cutoff of REI ≥ 14/h, subjects with an AHI ≥ 15 were identified with 77.8% sensitivity and 90.5% specificity. When applying this REI to the test group, it correlated closely with the AHI (r = 0.92) and identified subjects with an AHI ≥ 15 with 87.5% sensitivity and 91.3% specificity. While Fcv showed a modest correlation with AHI (r = 0.46 and 0.66 in the training and test groups), it lacked independent predictive power for AHI.ConclusionThe analysis of respiratory component of micromotion using piezoelectric rubber sheet sensors presents a promising approach for HSAT, providing a practical and effective means of estimating sleep apnea severity.

Rubber Compounds from Devulcanized Ground Tire Rubber: Recipe Formulation and Characterization.

In this study, our focus was on developing and investigating rubber recipes that are suitable for devulcanized ground tire rubber (dGTR). Devulcanized rubber has a powdery or sticky uncured rubber-like appearance depending on the extent of main-chain degradation that occurs with selective crosslinking scission. Still, it has a significantly shorter scorch time than a new rubber compound. Therefore, our primary goal was to slow down the vulcanization process of dGTR and improve its mechanical properties via recipe development. We formulated several recipes (sulfur-, peroxide-, and phenolic resin-based) and studied the vulcanization process and the main properties of the revulcanized rubber sheets. We observed that the vulcanization process could be altered with different vulcanization methods: using peroxide and vulcanizing resin extended the process significantly. Peroxide vulcanization also provided enhanced elongation compared to sulfuric systems. With a balance of properties in mind, we selected a semi-efficient sulfur-based recipe and studied the characteristics of natural rubber/dGTR mixtures with the help of plasticizer oils. We successfully replaced a notable portion of natural rubber with dGTR, maintaining its properties without much compromise.

Mechanically Durable Superhydrophobic Strain Sensors with High Biocompatibility and Sensing Performance for Underwater Motion Monitoring.

Much progress has been made toward the development of wearable flexible strain sensors with high sensing performance to monitor human motion, but continuous function in harsh aqueous environments remains a significant challenge. A promising strategy has been the design of sensors with highly durable superhydrophobicity and maintenance of unique sensing properties. Herein, an extremely durable superhydrophobic strain sensor with an ultrawide sensing range was simply fabricated by directly brushing conductive carbon black nanoparticles (CBNPs) onto an elastic silicone rubber sheet (SS) with poly(dimethylsiloxane) (PDMS) coatings (i.e., SS/PDMS-CBNPs sensors). First, this method avoided the use of toxic solvents and a conventional prestretching treatment. Second, considering the easily destroyed rough structures and surface chemistry for conventional superhydrophobic sensors during practical applications, the prepared SS/PDMS-CBNP sensors showed excellent mechanical durability of both superhydrophobicity and sensing as examined by harsh abrasion (300 cycles), stretching (up to 200%), and ultrasonication (40 min) treatments. Third, the prepared superhydrophobic strain sensor exhibited high sensitivity (gauge factor of 101.75), high stretchability (0.015-460%), low hysteresis (83 ms), and long-term stability (10000 cycles). Fourth, the high biocompatibility of the SS/PDMS-CBNP sensor was demonstrated by rabbit skin irritation tests. Finally, the remarkable water-repellent and sensing properties of the SS/PDMS-CBNP sensor allowed its application to monitor a swimmer's real-time situation and send distress signals when needed.

Towards Topological Geospatial Conflation: An Optimized Node-Arc Conflation Model for Road Networks

Geospatial data conflation is the process of identifying and merging the corresponding features in two datasets that represent the same objects in reality. Conflation is needed in a wide range of geospatial analyses, yet it is a difficult task, often considered too unreliable and costly due to various discrepancies between GIS data sources. This study addresses the reliability issue of computerized conflation by developing stronger optimization-based conflation models for matching two network datasets with minimum discrepancy. Conventional models match roads on a feature-by-feature basis. By comparison, we propose a new node-arc conflation model that simultaneously matches road-center lines and junctions in a topologically consistent manner. Enforcing this topological consistency increases the reliability of conflation and reduces false matches. Similar to the well-known rubber-sheeting method, our model allows for the use of network junctions as “control” points for matching network edges. Unlike rubber sheeting, the new model is automatic and matches all junctions (and edges) in one pass. To the best of our knowledge, this is the first optimized conflation model that can match nodes and edges in one model. Computational experiments using six road networks in Santa Barbara, CA, showed that the new model is selective and reduces false matches more than existing optimized conflation models. On average, it achieves a precision of 94.7% with over 81% recall and achieves a 99.4% precision when enhanced with string distances.

Rubber Sheet Geometry in Design Process

Rubber Sheet Geometry in Design Process

A lightweight and transparent acoustic metamaterial sheet with designed structures for sound insulation applications

Normal sound insulation materials such as metal plates and rubber sheets follow the mass law. According to the mass law, a weight increase of sound insulators leads to high sound insulation. Therefore, novel lightweight and high-performance materials have been required in various fields such as mobility and electronics. We developed lightweight and transparent acoustic metamaterial sheets having blocklike weights with rodlike or cylindrical shapes periodically arranged on thin films. Upon sound incidence at a target frequency, the heavier weights and the lighter film cooperatively vibrate in opposite phase and with the same amplitude. The transmitted sound waves through those parts cancel each other out owing to the wave interference. As a result, the acoustic metamaterial sheets show high sound insulation performance beyond the mass law limit at the target frequencies. In this study, we report the structural design, sound insulation properties and mechanisms, and application of acoustic metamaterial sheets.

Expansion of a mechano-chemical plant for remanufacturing waste tires into rubber sheet and profitable wire steel by-products: A quantitative sustainability assessment

Existing mechano-chemical plants remanufacture waste tires into rubber sheet and recover nylon fibers and metal wires. As a novel expansion of this process to improve its profitability and sustainability, this study proposes the integration of a pyrolysis–distillation system to produce energy products and machinery to produce by-products from the waste steel, such as galvanized wire, nails, and crimped mesh. A quantitative analysis was performed to evaluate the amount of steel wire, energy, and CO2 emissions saved by the proposed process. Furthermore, the potential profit was calculated at low and high potential scales, representing sustainable national and international development, respectively, with the aim of establishing a circular economy. Twenty-four alternatives based on technical variations were developed and their technical feasibility and potential profit were evaluated and ranked, providing valuable information for decision makers selecting plant layout options. The economic, environmental, and technical feasibility indexes were calculated and used to specify the social feasibility index. Finally, a quadrilateral-bottom-line sustainability development approach was used to calculate the final sustainability index, showing that the proposed integration is indeed a sustainable business approach. The findings of this study prove that there are significant benefits in expanding existing remanufacturing plants to extract value from the many different materials in waste tires.

PSIV-26 Development of a Controlled Exposure Particulate and Oxidative Radical Mask for Causality Experiments Investigating Smoke Exposure on Livestock Animals

Abstract Understanding and mapping the specific effects of smoke inhalation on cattle performance provides strategic insights for producers and policy makers to better prepare or adjust when faced with sporadic or even seasonal reductions in air quality. As of now, no current studies have attempted to investigate the effects of seasonal fires on performance and health adequately in livestock while addressing obvious confounding effects, controlling exposure, and examining fuel for differential oxidative radicals and particulate smoke. Herein, we propose the design of the first cost-effective controlled system for investigating smoke, particulate matter, and varied oxidative radicals through a pre-mixing chamber. The mask main body is constructed from 8” nominal diameter schedule 40 PVC pipe. The endcap was designed in an online CAD software to provide an interface for standard 2 ⅞” bulkhead fittings and was produced via additive manufacturing (3D printing). A silicone SCUBA neck seal was used to line the face orifice and is the component that directly contacts the animal’s nose and mouth. A neoprene rubber sheet and an insulation hose were used as padding under the silicone seal to help maintain an airtight connection and animal comfort when the mask is worn. Bulkhead fittings used provide 1 ½” female national pipe thread connection to allow for modular connection of inlet and outlet hoses, check valves for airflow isolation, filters, or any number of connections can be made via these gasket sealed fittings, making this platform extremely adaptable. In its shown configuration, 3D printed adapters were made to attach 4” suction hose to 2” socket union joints for quick connect/disconnect functionality. An inlet and outlet gas/smoke flow regulator are attached to a mixing chamber where particulate and chemical composition sensors are utilized to deliver the desired composition of smoke delivered to the animals. Negative pressure fans and pumps regulate the flow to the animals and are utilized for exposure of smoke in time-specific intervals. An additional fully 3D printed version enables the mask design to be lower in weight through regulation of the density of the internal matrix, and after an initial investment in the equipment also represents a cost-efficient approach to generating multiple masks. Understanding the effects of particulate and reactive oxidative molecules on livestock health and performance requires the study of a controlled exposure, the system presented herein represents a viable and cheap alternative for bettering a mechanistic model and understanding of the effects of smoke on animal health and performance. Ultimately, the proposed mask paired with currently available sensors permit for the controlled exposure of smoke particulate with different chemical compositions for accurate evaluation of prolonged exposure effects on livestock.

Effects of uniaxial tensile strain on the release of small molecules from silicone rubber

AbstractSilicone rubber materials may be subject to mechanical strains which can affect the transport properties of small molecules loaded in the materials such as plasticizers and active molecules, hence deteriorating their intended mechanical properties or affecting their performance as carriers of active molecules. Therefore, it is important to understand the effects of mechanical strains on transport of small molecules in the silicone rubber matrix. In this work, silicone rubber sheets loaded with 2 wt% triacetin were stretched and held at four different lengths up to 125% engineering strain. The mass transfer coefficients and diffusion coefficients of triacetin in the strained silicone rubber were determined by monitoring the release of triacetin using headspace gas chromatography–mass spectrometry. It was found that there was no significant change of diffusion coefficient as the applied strain increased, which might result from two microstructure changes that had conflicting effects on diffusion: chain orientation and free volume deformation.

Innovative design: Flexible conductive natural rubber electrode sheets with triboelectric generator activated by wheel rotation

Efficient consumption and clean energy management play a vital role in green energy. To be a part of this effort. Among the materials explored, flexible conductive electrodes utilizing triboelectric phenomena and unique properties of natural rubber composites have demonstrated a great potential for mechanical-to-electrical energy conversion. Fabrication process involves modifying natural rubber latex by incorporating conductive fillers such as carbon black, Ketjen black, and multiwall carbon nanotubes. The modified flexible conductive natural rubber sheets (CNRs) are then characterized for their structural and electrical properties. This structural arrangement significantly reduces the electrical resistance of the NR sheets. The incorporation of the MWCNT fillers leads to an increase in dielectric constant of CNRs. These properties are optimized via a proper design of the conductive natural rubber sheet triboelectric nanogenerator (CNRS-TENG). To enhance charge accumulation, polytetrafluoroethylene (PTFE) film is applied to the bottom surface of the CNRs. The CNRS-TENG are integrated into a wheel rotation generator setup. The output performance of the wheel rotation generator is influenced by the rotational speed as well as the arrangement of phases and segments. This work demonstrates that CNRs can be integrated with flexible electronic and other energy harvesting devices, opening possibilities for multifunctional clean energy solutions.