Fiberglass: Lateral Loads from Climatic and Temporary Factors

2021 ◽  
Vol 1031 ◽  
pp. 88-96
Author(s):  
Irina V. Zlobina
Keyword(s):  
Electromagnetic Field ◽  
Environmental Factors ◽  
Bending Strength ◽  
Lateral Loads ◽  
Functional Dependencies ◽  
Initial State ◽  
Term Operation ◽  
The Stability ◽  
Control Samples

The influence of modification of fiberglass in the cured state in the microwave electromagnetic field on the value of the limit stresses is significantly manifested when testing samples in the initial state. The increase in limit voltages is on average 7%. Tests of modified samples after exposure in full-scale conditions showed a decrease in the effect with an increase in the exposure time from 6% for exposure of 3 months to 3% for exposure of 8 months. This significantly increases the uniformity of the bending strength values in the batch, which is manifested in a decrease in the coefficient of variation of limit stresses relative to the control samples by 33%. Functional dependencies in the form of 2nd-order polynomials are obtained, which allow predicting the stability of products made of modified fiberglass for long-term operation under the influence of environmental factors with a confidence of up to 98%.

ASSESSMENT OF THE STABILITY OF CARBON FIBER TO THE ACTION OF TRANSVERSE LOADS TAKING INTO ACCOUNT TIME AND CLIMATE FACTORS

2021 ◽  
pp. 3-11
Author(s):  
I. V. Zlobina
Keyword(s):  
Electromagnetic Field ◽  
Carbon Fiber ◽  
Environmental Factors ◽  
Bending Strength ◽  
Negative Influence ◽  
Strengthening Effect ◽  
Functional Dependencies ◽  
Experimental Conditions ◽  
Term Operation ◽  
The Stability

The relevance of research in the development of physical methods for increasing the stability of products made of polymer composite materials (PCM) to the influence of environmental factors, taking into account its duration, is shown. The influence of exposure of carbon fiber samples on an epoxy matrix in the natural conditions of the climate zone of Saratov on the change in the limit stresses of three-point bending was studied. Comparative tests of samples premodified in a microwave electromagnetic field with a frequency of 2.45 GHz with an energy flux density (17…18)×104 µw/cm2 were performed. It is shown that the influence of environmental factors leads to a decrease in the limit stresses by (3,7…10,4) % depending on the exposure. Modification of carbon fiber in the cured state in the microwave electromagnetic field reduces the negative influence of the external environment by reducing the strength by (44.3…73) %. It was found that the strengthening effect of microwave modification increases with increasing exposure from 6 % to 11.5 % under the accepted experimental conditions, while the uniformity of the bending strength values in the batch increases significantly, which is manifested in a decrease in the coefficient of variation of limit stresses by (70.2…77.8) %. Functional dependencies in the form of 2nd-order polynomials are obtained, allowing with confidence (98…99) % predict the stability of products made of modified carbon fiber during long-term operation under the influence of environmental factors.

CORRELATION DEPENDENCES OF THE BENDING STRENGTH OF POLYMER COMPOSITE MATERIALS MODIFIED IN A MICROWAVE ELECTROMAGNETIC FIELD ON THE MOISTURE CONTENT DURING EXPOSURE IN FULL-SCALE CONDITIONS

2021 ◽  
pp. 3-9
Author(s):  
I. V. Zlobina ◽  
I. S. Katsuba
Keyword(s):  
Electromagnetic Field ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Moisture Content ◽  
Bending Strength ◽  
Climatic Factors ◽  
Experimental Studies ◽  
Three Point Bending ◽  
Treated Carbon ◽  
Control Samples

Experimental studies of the influence of external climatic factors, taking into account exposure, on the change in the bending strength of control and microwave – treated carbon and fiberglass samples in the cured state were performed. An increase in the limit stresses of three – point bending of experimental carbon fiber samples compared to the control ones was found by 7…12 %, and fiberglassby 4…7 %. It is shown that with an increase in exposure to 14 months, the strength of control samples of carbon and fiberglass decreases by an average of 10 %. At the same time, the strength of the prototypes is reduced only by 4.4 %. With an increase in the moisture content of both control and experimental samples, a decrease in their strength is observed. In this case, the linear correlation is average (from– 0.44 to – 0.615). It is established that for experimental samples, the influence of the amount of absorbed moisture on the strength is manifested to a much lesser extent. For carbon fiber, the reduction is 16.6 %, for fiberglass – 12 %.

Detection method for stability of microcontroller accessories based on biosensor

2021 ◽  
pp. 1-14
Author(s):  
Yan Ren ◽  
Jiayong Liu
Keyword(s):  
Process Design ◽  
Detection Method ◽  
Detection Accuracy ◽  
Stability Testing ◽  
Term Operation ◽  
Existing Problems ◽  
Testing Method ◽  
And Performance ◽  
The Stability

In order to solve the problem of poor accuracy of traditional microcontroller attachment stability testing method, a microcontroller attachment stability testing method based on biosensor was designed to solve the existing problems. The reliability test index of the microcontroller is established, then the interference of the microcontroller accessory is detected and responded, and the interference detection signal of the microcontroller accessory is selected. The process design of stability detection of microcontroller accessories based on biosensor is completed. The experimental results show that the stability detection method based on biosensor designed in this paper can ensure the stability detection accuracy of microcontroller accessories above 80%, which is more accurate than traditional methods. It can be used to evaluate the stability, reliability and performance of microcontroller accessories in long-term operation.

Analysis of the fracture surface of steel 10 in the initial state and after long-term operation

1987 ◽  
Vol 29 (10) ◽  
pp. 788-791
Author(s):  
B. S. Ermakov ◽  
G. G. Kolchin ◽  
A. Z. Kevesh
Keyword(s):  
Fracture Surface ◽  
Initial State ◽  
Term Operation

Performance Stability of Recycle Amine-Free Water-Soluble Coolant in Long Term Operation

2014 ◽  
Vol 625 ◽  
pp. 530-535
Author(s):  
Kenji Yamaguchi ◽  
Yasuo Kondo ◽  
Satoshi Sakamoto ◽  
Mitsugu Yamaguchi ◽  
Ryoichi Nakazawa
Keyword(s):  
Environmental Effect ◽  
Free Water ◽  
Water Soluble ◽  
Water Recovery ◽  
Machining Processes ◽  
Cooling Performance ◽  
Recycling System ◽  
Term Operation ◽  
The Stability

Recently, the concern for the environment has been increasing rapidly. In machining processes, the treatment of water-soluble coolants waste has caused environmental problems. Water-soluble coolants contain surfactants, preservatives, and corrosion inhibitors for maintaining the stability and performance of the coolants. To reduce the management cost and environmental effect of water-soluble coolants, the authors have been studying a recycling system for water-soluble coolants. In the recycling system, oil-free recycle water is isolated from the coolant waste and reused as a diluent of the new coolant. The authors have been developing different types of water recovery methods for the recycling system, and the recovered water from the coolant waste has potential as a diluent for a new coolant. In this report, we focused on the amine (alkanolamine) -free water-soluble coolant. Some amine-free water-soluble coolants have been developed and are commercially available. A reduction in the environmental effect in the waste treatment of coolants is expected with amine-free coolants. We have demonstrated that the amine-free water-soluble coolant has equal or better cooling and lubricating performance compared with the conventional amine-containing coolant. In addition, the amine-free coolant shows good recyclability for the recycling system. The processing time of the recycling treatment of the amine-free coolant has been decreased by half with our recycling process compared with the conventional amine-containing coolant. In this report, we examined the stability, cooling performance and lubricating performance of the recycle amine-free water-soluble coolant in long term operation. The recycle amine-free water-soluble coolant is operated in a 3-axis machining center for several months. We observed concentration, pH, corrosion inhibition performance, cooling performance, and lubricating performance of the coolant. The results from these experiments show the amine-free water-soluble coolant has the advantage to use in the recycling system for water-soluble coolant.

scholarly journals Rail Track with Rail Compression

2021 ◽  
Vol 20 (3) ◽  
pp. 234-242
Author(s):  
V. N. Sukhodoev
Keyword(s):  
Effective Property ◽  
Operating Conditions ◽  
Design Parameters ◽  
Labor Costs ◽  
Term Operation ◽  
Rail Track ◽  
Loading And Unloading ◽  
The Stability ◽  
The Cost

The problem of damping the noise on the track, arising from the movement of the train, is solved sufficiently but it is simple, if the rail with spacers is laid inside the longitudinally located band sleeper-mechanism. The result is a layered rail thread, consisting of belts: a rail tape with elastic spacers on three sides, a tie-mechanism tape and a ballast layer. The unity of the layers is carried out due to their own mass. This is the static track without external load. Rail compression is an effective property of rail tracks. It is formed in the sleeper mechanism under the influence of vertical forces with displacements and their horizontal derivatives. When loading the track, the compression is carried out repeatedly with subsequent unloading.n this case, each previous changes in the conditions in work of the track are taken into account in the subsequent cycle of loading and unloading. A rail track with a rail compression is a kind of self-adapting linear system, which is necessary with frequent changes in load and operating conditions for silent performance of a functional purpose. The specificity of this path is that the movement of the wheel creates rail vibration and noise, which are immediately damped by compression with damping. The balance between the occurrence of noise and its suppression is achieved by the ratio of the lengths of half-sleeper shoulders as a lever. The condition for the appearance of a shift of the compression forces in the direction from vertical shoulder of the half-sleepers is the unequal settlements of the horizontal shoulder of the L-shaped half-sleepers and its eccentric loading. As a result of the research, the advantages of a rail track with rail compression have been revealed, which is a guarantor of the stability of the design parameters during long-term operation of the track. The cost of a rail track with rail reduction is halved as a result of steel savings, lower labor costs and operational needs.

Targeted filling of silica in Nafion by a modified in situ sol–gel method for enhanced fuel cell performance at elevated temperatures and low humidity

2019 ◽  
Vol 55 (38) ◽  
pp. 5499-5502 ◽  
Author(s):  
Guoxiao Xu ◽  
Shuai Li ◽  
Jing Li ◽  
Zhao Liu ◽  
Ying Li ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Sol Gel ◽  
Silica Network ◽  
Fuel Cell Performance ◽  
Term Operation ◽  
Ionic Cluster ◽  
Low Humidity ◽  
The Stability

By facilely utilizing an ionic cluster as a nano-reactor, a silica network can be targeted filled in Nafion to increase the PEMFC performance at elevated temperatures and low humidity. Moreover, the stability of Nafion can be improved for the long-term operation of PEMFC under harsh conditions.

scholarly journals Functionality of Beech Bark in Adhesive Mixtures Used in Plywood and Its Effect on the Stability Associated with Material Systems

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1298 ◽  
Author(s):  
Roman Réh ◽  
Rastislav Igaz ◽  
Ľuboš Krišťák ◽  
Ivan Ružiak ◽  
Milada Gajtanska ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Urea Formaldehyde ◽  
Wood Processing ◽  
Material Systems ◽  
Adhesive Mixtures ◽  
The Common ◽  
The Stability ◽  
Heating Up

The results of research into utilizing grinded beech bark in order to substitute commonly used fillers in urea formaldehyde (UF) adhesive mixtures to bond plywood are presented in the present study. Four test groups of plywood with various adhesive mixtures were manufactured under laboratory conditions and used for experimentation. Plywood made using the same technology, with the common filler (technical flour), was used as a reference material. Three different concentrations of grinded beech bark were used. The thermal conductivity of the fillers used, viscosity and its time dependence, homogeneity and the dispersion performance of fillers were evaluated in the analysis of adhesive mixture. The time necessary for heating up the material during the pressing process was a further tested parameter. The produced plywood was analyzed in terms of its modulus of elasticity, bending strength, perpendicular tensile strength and free formaldehyde emissions. Following the research results, beech bark can be characterized as an ecologically friendly alternative to technical flour, shortening the time of pressing by up to 27%. At the same time, in terms of the statistics, the mechanical properties and stability of the material changed insignificantly, and the formaldehyde emissions reduced significantly, by up to 74%. The utilization of bark was in compliance with long-term sustainability, resulting in a decrease in the environmental impact of waste generated during the wood processing.

scholarly journals Effect of Additives Ag and Rare‐Earth Elements Y and Sc on the Properties of Hydrogen Sensors Based on Thin SnO2 Films during Long‐Term Testing

Coatings ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 423 ◽  
Author(s):  
Maksimova ◽  
Almaev ◽  
Sevastyanov ◽  
Potekaev ◽  
Chernikov ◽  
...  
Keyword(s):  
Tin Dioxide ◽  
Oxygen Adsorption ◽  
Hydrogen Sensors ◽  
Band Bending ◽  
Term Operation ◽  
Adsorption Sites ◽  
Effect Of Additives ◽  
Clean Air ◽  
The Stability

The paper presents the results of an investigation of the nanostructure, elements, and phase composition of thin (100–140 nm) tin dioxide films obtained via magnetron sputtering and containing Ag, Y, Sc, Ag + Y, and Ag + Sc additives in the volume. Electrical and gas‐sensitive characteristics of hydrogen sensors based on these films with dispersed Pt/Pd layers deposited on the surface were studied. The additives had a significant effect on the nanostructure of the films, the density of oxygen adsorption sites on the surface of tin dioxide, the band bending at the grain boundaries of tin dioxide, the resistance values in pure air, and the responses to hydrogen in the concentration range of 50–2000 ppm. During the long‐term tests of most of the samples studied, there was an increase in the resistance of the sensors in clean air and in the response to hydrogen. It has been established that the joint introduction of Ag + Y into the volume of films prevents the increase in the resistance and response. For these sensors based on thin films of Pt/Pd/SnO2:Sb, Ag, Y the responses to 100 and 1000 ppm of H2 are 25 and 575, correspondingly, the response time at exposure to 100 and 1000 ppm of H2 are 10 and 90 s, the recovery time at exposure to 100 and 1000 ppm of H2 17 and 125 s. Possible mechanisms of the effect of additives on the properties of sensors and the stability of their parameters during long‐term operation were considered.

scholarly journals Stability Analysis on the Long-Term Operation of the Horizontal Salt Rock Underground Storage

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Chengzhong Zhang ◽  
Qiang Zhang ◽  
Weiwei Li ◽  
Zhanping Song ◽  
Junbao Wang
Keyword(s):  
Underground Storage ◽  
Salt Rock ◽  
Height Ratio ◽  
Design Capacity ◽  
Term Operation ◽  
Operation Process ◽  
The Stability ◽  
Rock Deposit ◽  
Optimal Diameter

The construction of the vertical cavern in the salt dome deposit can meet the requirements of both storage capacity and tightness. However, if the vertical cavern is still used as the design shape of the salt rock underground storage in the layered salt rock deposit, the high design capacity cannot be guaranteed while the tightness is satisfied. In this case, the use of a large-span horizontal cavern as the design shape of the salt rock storage can not only effectively increase the design capacity of the storage, but also solve the problems such as the stability and tightness of the storage during the operation period by improving the structural form and working mode. Based on this, the ellipsoid-shaped horizontal salt rock underground storage is taken as an example, and a single-cavern horizontal salt rock underground storage model with different diameter-to-height ratios is established by using FLAC3D software. The change law of vertical and horizontal displacements, volume loss rate, and plastic zone distribution of salt rock storage changing with the diameter-to-height ratio are studied, and the optimal diameter-to-height ratio is determined. And then the long-term operation process of the double-cavern horizontal salt rock underground storage under the optimal diameter-to-height ratio is simulated, and the optimal pillar width is obtained.

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