The thesis had a deep research about the fiberglass filter paper's influence on the PM2.5 assaying. It has chosen XRF to make a quantitative analysis. Based on multiple regression theory it regard fiberglass filter p...The thesis had a deep research about the fiberglass filter paper's influence on the PM2.5 assaying. It has chosen XRF to make a quantitative analysis. Based on multiple regression theory it regard fiberglass filter paper's quality, element content and the quality of the loaded sample as independent variable, while the element's quality that the sample has collected as dependent variable. Furthermore, it has established four multiple quadric response surface models which concerning Ca by using of Mathematica and Matlab: Y = 0.8649-2.094x1-2.08x2 -1.375x3-10.58x1x2+8.53x1x3+1.549x2x3-3.443x1^2+6.555x2^2+6. 547x3^2; Y = 0.8649-2.094x1-2.08x2-1.375x3; Y = 0.8649 -2.094x2-2.08x2-1.375x3-3.443x1^2+6.525x2^2+6.547x3^2 ; Y =0.8649-2.094x1-2.08x2-1.375x3-10.58x1x2+8.53x1x3+1.549x2x3. After comparison it has finally found the best model. In combining with the sample it present a multiple data fitting analysis method which could adjust the fiberglass filter paper model accordingly.展开更多
The feasibility of photocatalytic degradation of organochlorine compounds using TiO 2 supported on fiberglass cloth as a photocatalyst was studied. The results showed that 2 0×10 -4 mol/dm 3 of dichloroeth...The feasibility of photocatalytic degradation of organochlorine compounds using TiO 2 supported on fiberglass cloth as a photocatalyst was studied. The results showed that 2 0×10 -4 mol/dm 3 of dichloroethylene, trichloroethylene and tetrachloroethylene can be completely photocatalytically degraded within a short time under illumination with a 375W medium pressure mercury lamp. The effects of parameters such as illumination time, initial concentration of organochlorine compounds, amount of air flow and concentration of H 2O 2 on the photocatalytic degradation were investigated. The TiO 2 supported on the fiberglass was not easily detached and after 500h illumination there was no significant loss of photocatalytic activity of TiO 2. The passible mechanisms of photocatalytic degradation were discussed.展开更多
The coated fiberglass fabric was prepared to protect personnel and equipment from sparks, heat, and molten metals during hot work projects. Ferric oxide powder 2%,mica powder6%,wollastonite powder 4%,and white carbon ...The coated fiberglass fabric was prepared to protect personnel and equipment from sparks, heat, and molten metals during hot work projects. Ferric oxide powder 2%,mica powder6%,wollastonite powder 4%,and white carbon black 8% were added in the phenyl methyl silicone to prepare the composite silicone solution. The french chalk and coupling agent can effectively solve the deposition of fillers in the coating solution. Compared with the original fiberglass fabric,heat resistance of the coated fabric under high temperature was greatly improved, and the temperature limitation in short period was higher than 900℃. Horizontal flammability tests showed that the coated fabric was non-combustible with no melting and no fragments. The temperature for long period usage of coated fabric was lower than 500 ℃. Welding drop test showed that the coating could prevent the molten metals,sparks and heat from transferring in the fabric. Test for toxic gas release showed that the toxic gases such as HCN,SO_2,HCl,and HF were not detected,only CO( 100 mg / m^3) and NO( 12 mg /m^3) were detected,and their concentrations were far lower than the limitation values CO( 4 375 mg / m^3) and NO( 134 mg /m^3). The breaking strength of coated fabric was almost twice the strength of the original fabric,and the coated surface had good water and oil repellency.展开更多
CNPC implements the call of energy conservation and emission reduction, and promotes the application of new energy conservation and emission reduction technologies and new products to achieve production and reduce pol...CNPC implements the call of energy conservation and emission reduction, and promotes the application of new energy conservation and emission reduction technologies and new products to achieve production and reduce pollution. As China’s oilfields enter the period of high water cut development, corrosion problem and scale formation ordinary steel tubing are becoming more and more serious in oilfield application, which influence and restrict the production and development and bring about energy waste. FRP tubing has been widely used in oil and gas fields because of its excellent corrosion resistance, small friction coefficient and less wear. With the gradual popularization of FRP tubing in oilfields, failure cases also show a growing trend as threaded release, leakage, fracture and so on, which affect the normal production of oilfields. In this paper, a series of key performance properties affecting service performance of high-pressure FRP tubing are tested which took from common failure cases. The key properties of FRP tubing, such as unloading, anti-collapse, short-term failure pressure at high ambient temperature and high ambient temperature axial tension, are tested in the research. The article provides a scientific basis for applicability evaluation of FRP tubing. This research has important significance for energy saving, decreasing pollution and safe operation of tubing pipes. Several suggestions are put forward on material selection and design of FRP tubing.展开更多
In order to delay or eliminate the occurrence and expansion of the reflective cracking in the asphalt concrete overlay on old cement concrete pavement, an epoxy asphalt geogrid stress-absorbing layer( EAGSAL) was de...In order to delay or eliminate the occurrence and expansion of the reflective cracking in the asphalt concrete overlay on old cement concrete pavement, an epoxy asphalt geogrid stress-absorbing layer( EAGSAL) was designed. The EAGSAL consists of epoxy asphalt and fiberglass geogrid. The pull-out test, skewshearing test, bending beam test and fatigue test were conducted to evaluate the performance of the EAGSAL and a traditional stress-absorbing layer( TSAL). The results showthat the adhesive performance, shear performance, bending strength and fatigue performance of the EAGSAL with an optimal spraying volume of epoxy asphalt are better than those of optimally designed TSAL, and the maximum bending strain of the EAGSAL is very close to that of the TSAL. The EAGSAL has superior performance in reflective cracking resistance.Moreover, the EAGSAL with the optimal spraying volume of approximately 2. 0 L m^2 is thinner and lighter than the TSAL,which can decrease the thickness and improve the bearing ability of the whole pavement structure.展开更多
Based on the harmonic vibration equation, the relationship between IR characteristic peak of fiberglass and Si-O-Si bond angle was deduced, and 1 100 cm^-1 characteristic peak was specifically studied. It is found tha...Based on the harmonic vibration equation, the relationship between IR characteristic peak of fiberglass and Si-O-Si bond angle was deduced, and 1 100 cm^-1 characteristic peak was specifically studied. It is found that 1 100 cm^-1 characteristic peak shifts to higher wave number when Si-O-Si bond angle increases. Taking fused biconical taper (FBT) coupler as an example, the microstructures of the fiber coupler manufactured at different draw- ing speeds were tested with micro infrared spectrum. According to the test results, it is found that the bond angle at the taper region is the largest, the one at the fused region is the second largest, and the one of bare fiber is the smal- lest. The characteristic peaks of fused-taper region shift to higher wave number when drawing speed increases.展开更多
In this paper, we investigate the properties of an alternative material for use in marine engineering, namely a rigid and light sandwich-structured composite made of expanded polystyrene and fiberglass. Not only does ...In this paper, we investigate the properties of an alternative material for use in marine engineering, namely a rigid and light sandwich-structured composite made of expanded polystyrene and fiberglass. Not only does this material have an improved section modulus, but it is also inexpensive, light, easy to manipulate, and commercially available in various sizes. Using a computer program based on the finite element method, we calculated the hogging and sagging stresses and strains acting on a prismatic boat model composed of this material, and determined the minimum sizes and maximum permissible stresses to avoid deformation. Finally, we calculated the structural weight of the resulting vessel for comparison with another structure of comparable dimensions constructed from the commonly used core material Divinycell.展开更多
AIM To determine if complete, split casts and backslabs [plaster of Paris(POP) and fiberglass] generate different intracast pressures and pain. METHODS Increased swelling within casts was modeled by a closed water sys...AIM To determine if complete, split casts and backslabs [plaster of Paris(POP) and fiberglass] generate different intracast pressures and pain. METHODS Increased swelling within casts was modeled by a closed water system attached to an expandable bag placed directly under different types of casts applied to a healthy lower limb. Complete fiberglass and POP casts, split casts and backslabs were applied. Twenty-five milliliter aliquots of saline were injected into the system and the generated intracast pressures were measured using a sphygmomanometer. The subject was blinded to the pressure scores to avoid bias. All casts were applied to the same right limb on the same subject to avoid the effects of variations in anatomy or physiology on intracast pressures. Pain levels were evaluated using the Visual Analogue Score after each sequential saline injection. Each type of cast was reapplied four times and the measurements were repeated on four separate occasions. Sample sizes were determined by a pre-study 90% power calculation to detect a 20% difference in intracast pressures between cast groups. RESULTS A significant difference between the various types of casts was noted when the saline volume was greater than 100 mL(P = 0.009). The greatest intracast pressure was generated by complete fiberglass casts, which were significantly higher than complete POP casts or backslabs(P = 0.018 and P = 0.008 respectively) at intracast saline volumes of 100 mL and higher. Backslabs produced a significantly lower intracast pressure compared to complete POP only once the saline volume within casts exceeded 225 mL(P = 0.009). Intracast pressures were significantly lower in split casts(P = 0.003). Split POP and fiberglass casts produced the lowest intracast pressures, even compared to backslabs(P = 0.009). Complete fiberglass casts generated the highest pain levels at manometer pressures of 75 mm Hg and greater(P = 0.001). Split fiberglass casts had significantly reduced pain levels(P = 0.001). In contrast, a split complete POP cast did not produce significantly reduced pain levels at pressures between 25-150 mmH g. There was no difference in pain generated by complete POP and backslabs at manometer pressures of 200 mm Hg and lower. CONCLUSION Fibreglass casts generate significantly higher intracast pressures and pain than POP casts. Split casts cause lower intracast pressures regardless of material, than complete casts and backslabs.展开更多
The emission of fine particulates from the burning of coal can pose a number of problems for human health and the environment.The bag filter is an equipment capable of preventing these particles from reaching the atmo...The emission of fine particulates from the burning of coal can pose a number of problems for human health and the environment.The bag filter is an equipment capable of preventing these particles from reaching the atmosphere.The present work evaluated and proposed improvements based on information received from a process of a company producing vegetable bran and oils,which acts with high emission of particulates.The filter sleeves used were fiberglass fabric with expanded polytetrafluoroethylene membrane.Physical,mechanical and granulometric laboratory analyzes were performed,as well as scanning electron microscopy and dispersive energy spectroscopy for the characterization of the tissue and particulate matter.Based on the results,a new specification of stainless steel cage was proposed for the filter in order to improve the efficiency of retention,as well as to increase the useful life of the filter elements.展开更多
A new strategy to prevent the biofouling of water-submerged surfaces is presented here. In particular, the authors showthat carbonic anydrase from Methanosarcina thermophila can be entrapped into polyacrylic paints, p...A new strategy to prevent the biofouling of water-submerged surfaces is presented here. In particular, the authors showthat carbonic anydrase from Methanosarcina thermophila can be entrapped into polyacrylic paints, preserving enzyme activity. In addition, the authors also show that enzyme-containing paints inhibit the growth of marine microorganims, preventing biofouling.展开更多
The effect of modifying the surface of multiwall carbon nanotubes (CNT’s) by oxygen and nitrogen on the strength characteristics of the fiberglass filled with them was investigated by testing for tension and bending....The effect of modifying the surface of multiwall carbon nanotubes (CNT’s) by oxygen and nitrogen on the strength characteristics of the fiberglass filled with them was investigated by testing for tension and bending. The method of obtaining nitrogen-containing nanostructures is developed. It was shown that in the epoxide system LR285-LH286 hydrophobic CNT’s (outgoing) at introducing into the catalyst polymerization of LH286, increase the strength with respect to unreinforced CNT’s by 48% - 54%. Oxidized CNT’s (200 A?h/kg) introduced into the resin LR285 increase the strength by 59%. The distribution of the filler particles in size, both in the epoxy resin and in the catalyst, depends on their concentration nonlinear, and correlates with the strength characteristics of the composite.展开更多
In this article,theoretical calculations on the bending performance(bending strength and bending modulus)of fiberglass reinforced plastic(FRP)honeycomb sandwich structures were conducted initially,and then the bending...In this article,theoretical calculations on the bending performance(bending strength and bending modulus)of fiberglass reinforced plastic(FRP)honeycomb sandwich structures were conducted initially,and then the bending performance of two FRP honeycomb sandwich structures with different thicknesses were measured by the Aerospace Materials Failure Analysis Center.By comparing and analyzing the theoretical calculations and experimental results,it was found that the theoretical calculated bending strength and bending modulus were in good agreement with those of the experimental tested within 26.5%.When designers and technicians conduct theoretical calculations on the performance of FRP honeycomb sandwich structures,they can use the formulas derived in this article,which will more accurately predict the mechanical properties of components made of composite materials.展开更多
The energy efficiency of a building depends on building envelope performance.The results presented in this paper are the first of a long-term building envelope research project at the Alternative Village at the Univer...The energy efficiency of a building depends on building envelope performance.The results presented in this paper are the first of a long-term building envelope research project at the Alternative Village at the University of Manitoba in Winnipeg,Manitoba,Canada.Five test buildings were constructed using the following systems:two wood frames with fiberglass batt insulation and dense pack cellulose,one polyurethane structural insulated panels(PUR SIP),and two with the Stay in place PVC concrete form building system using 102mm and 204mm of concrete externally insulated with 102mm of expanded polystyrene foam.All of the buildings had a common foundation and roof system with a footprint of 23.8 m2.Blower door tests were conducted to determine air tightness.Each structure was heated with an electrical resistance heater and maintained at a constant internal temperature.The thermal gradient through the wall and power consumption were monitored.The study period discussed in this report represents the main heating season from October 2011 to April 2012 consisting of 209 days.Based on the power consumption,the PUR SIP consumed the least at 2498 kWh,while the 204 mm Stay in place PVC concrete form building used the most at 2898 kWh for the same time period.The thermal gradient through the cross section of the wood frame structures was compared through the cavity insulation and at the stud.It was found that the cellulose building provided better thermal resistance along the stud when compared to the fiberglass batt insulation.展开更多
Intensification of pollution loading worldwide has promoted an escalation of different types of disease-causing microorganisms, such as harmful algal blooms(HABs), instigating detrimental impacts on the quality of rec...Intensification of pollution loading worldwide has promoted an escalation of different types of disease-causing microorganisms, such as harmful algal blooms(HABs), instigating detrimental impacts on the quality of receiving surface waters. Formation of unwanted disinfection by-products(DBPs) resulting from conventional disinfection technologies reveals the need for the development of new sustainable alternatives. Quaternary Ammonium Compounds(QACs) are cationic surfactants widely known for their effective biocidal properties at the ppm level. In this study, a novel silica-based antimicrobial nanofilm was developed using a composite of silica-modified QAC(Fixed-Quat) and applied to a fiberglass mesh as an active surface via sol–gel technique. The synthesized Fixed-Quat nanocoating was found to be effective against E. coli with an inactivation rate of 1.3 × 10^(-3) log reduction/cm min. The Fixed-Quat coated fiberglass mesh also demonstrated successful control of Microcystis aeruginosa with more than 99% inactivation after 10 hr of exposure.The developed antimicrobial mesh was also evaluated with wild-type microalgal species collected in a water body experiencing HABs, obtaining a 97% removal efficiency. Overall,the silica-functionalized Fixed-Quat nanocoating showed promising antimicrobial properties for water disinfection and HABs control, while decreasing concerns related to DBPs formation and the possible release of toxic nanomaterials into the environment.展开更多
Biological structural fixed joints exhibit unique attributes, including highly optimized fiber paths which minimize stress concentrations. In addition, since the joints consist of continuous, uncut fiber architectures...Biological structural fixed joints exhibit unique attributes, including highly optimized fiber paths which minimize stress concentrations. In addition, since the joints consist of continuous, uncut fiber architectures, the joints enable the organism to transport information and chemicals from one part of the body to the other. To the contrary, sections of man-made composite material structures are often joined using bolted or bonded joints, which involve low strength and high stress concentrations. These methods are also expensive to achieve. Additional functions such as fluid transport, electrical signal delivery, and thermal conductivity across the joints typically require parasitic tubes, wires, and attachment clips. By using the biomimetic methods, we seek to overcome the limitations which are present in the conventional methods. In the present work, biomimetic co-cured composite sandwich T-joints were constructed using unidirectional glass fiber, epoxy resin, and structural foam. The joints were fabricated using the wet lay-up vacuum bag resin infusion method. Foam sandwich T-joints with multiple continuous fiber architectures and sandwich foam thickness were prepared. The designs were tested in quasi-static bending using a mechanical load frame. The significant weight savings using the biomimetic approaches is discussed, as well as a comparison of failure modes versus architecture is described.展开更多
Blanking is one of the high speed processes to produce fiat products from sheets economically. In order to expand this process to new materials, the blanking of polyvinyl chloride (PVC)/fiberglass thermoplastic com-...Blanking is one of the high speed processes to produce fiat products from sheets economically. In order to expand this process to new materials, the blanking of polyvinyl chloride (PVC)/fiberglass thermoplastic com- posite laminates and composite/aluminum hybrid laminates was investigated. The laminates were produced by the film stacking procedure and then blanked by circular die and punches. The blanking process was done in two levels of clearance including 4% and 8% of the laminates thickness, two levels of punch speed including 40 mm/min and 200 mm/min and at two levels of temperature (room tem- perature and 80 ℃) for both composite and hybrid laminates. The effects of the parameters on the maximum blanking force, cutting energy, and quality and precision of sheared edges were studied. Cutting mechanism for blanking in different conditions was explained. It was concluded that at room temperature, blanked composite and hybrid laminates had a high quality of sheared edges but at elevated temperature, although the maximum blanking force was reduced, the quality of sheared edge was reduced significantly.展开更多
文摘The thesis had a deep research about the fiberglass filter paper's influence on the PM2.5 assaying. It has chosen XRF to make a quantitative analysis. Based on multiple regression theory it regard fiberglass filter paper's quality, element content and the quality of the loaded sample as independent variable, while the element's quality that the sample has collected as dependent variable. Furthermore, it has established four multiple quadric response surface models which concerning Ca by using of Mathematica and Matlab: Y = 0.8649-2.094x1-2.08x2 -1.375x3-10.58x1x2+8.53x1x3+1.549x2x3-3.443x1^2+6.555x2^2+6. 547x3^2; Y = 0.8649-2.094x1-2.08x2-1.375x3; Y = 0.8649 -2.094x2-2.08x2-1.375x3-3.443x1^2+6.525x2^2+6.547x3^2 ; Y =0.8649-2.094x1-2.08x2-1.375x3-10.58x1x2+8.53x1x3+1.549x2x3. After comparison it has finally found the best model. In combining with the sample it present a multiple data fitting analysis method which could adjust the fiberglass filter paper model accordingly.
文摘The feasibility of photocatalytic degradation of organochlorine compounds using TiO 2 supported on fiberglass cloth as a photocatalyst was studied. The results showed that 2 0×10 -4 mol/dm 3 of dichloroethylene, trichloroethylene and tetrachloroethylene can be completely photocatalytically degraded within a short time under illumination with a 375W medium pressure mercury lamp. The effects of parameters such as illumination time, initial concentration of organochlorine compounds, amount of air flow and concentration of H 2O 2 on the photocatalytic degradation were investigated. The TiO 2 supported on the fiberglass was not easily detached and after 500h illumination there was no significant loss of photocatalytic activity of TiO 2. The passible mechanisms of photocatalytic degradation were discussed.
基金National Natural Science Foundation of China(No.51206122)Natural Science Foundation of Tianjin,China(No.13JCQNJC03000)
文摘The coated fiberglass fabric was prepared to protect personnel and equipment from sparks, heat, and molten metals during hot work projects. Ferric oxide powder 2%,mica powder6%,wollastonite powder 4%,and white carbon black 8% were added in the phenyl methyl silicone to prepare the composite silicone solution. The french chalk and coupling agent can effectively solve the deposition of fillers in the coating solution. Compared with the original fiberglass fabric,heat resistance of the coated fabric under high temperature was greatly improved, and the temperature limitation in short period was higher than 900℃. Horizontal flammability tests showed that the coated fabric was non-combustible with no melting and no fragments. The temperature for long period usage of coated fabric was lower than 500 ℃. Welding drop test showed that the coating could prevent the molten metals,sparks and heat from transferring in the fabric. Test for toxic gas release showed that the toxic gases such as HCN,SO_2,HCl,and HF were not detected,only CO( 100 mg / m^3) and NO( 12 mg /m^3) were detected,and their concentrations were far lower than the limitation values CO( 4 375 mg / m^3) and NO( 134 mg /m^3). The breaking strength of coated fabric was almost twice the strength of the original fabric,and the coated surface had good water and oil repellency.
文摘CNPC implements the call of energy conservation and emission reduction, and promotes the application of new energy conservation and emission reduction technologies and new products to achieve production and reduce pollution. As China’s oilfields enter the period of high water cut development, corrosion problem and scale formation ordinary steel tubing are becoming more and more serious in oilfield application, which influence and restrict the production and development and bring about energy waste. FRP tubing has been widely used in oil and gas fields because of its excellent corrosion resistance, small friction coefficient and less wear. With the gradual popularization of FRP tubing in oilfields, failure cases also show a growing trend as threaded release, leakage, fracture and so on, which affect the normal production of oilfields. In this paper, a series of key performance properties affecting service performance of high-pressure FRP tubing are tested which took from common failure cases. The key properties of FRP tubing, such as unloading, anti-collapse, short-term failure pressure at high ambient temperature and high ambient temperature axial tension, are tested in the research. The article provides a scientific basis for applicability evaluation of FRP tubing. This research has important significance for energy saving, decreasing pollution and safe operation of tubing pipes. Several suggestions are put forward on material selection and design of FRP tubing.
基金The National Natural Science Foundation of China(No.51178114,51378122)
文摘In order to delay or eliminate the occurrence and expansion of the reflective cracking in the asphalt concrete overlay on old cement concrete pavement, an epoxy asphalt geogrid stress-absorbing layer( EAGSAL) was designed. The EAGSAL consists of epoxy asphalt and fiberglass geogrid. The pull-out test, skewshearing test, bending beam test and fatigue test were conducted to evaluate the performance of the EAGSAL and a traditional stress-absorbing layer( TSAL). The results showthat the adhesive performance, shear performance, bending strength and fatigue performance of the EAGSAL with an optimal spraying volume of epoxy asphalt are better than those of optimally designed TSAL, and the maximum bending strain of the EAGSAL is very close to that of the TSAL. The EAGSAL has superior performance in reflective cracking resistance.Moreover, the EAGSAL with the optimal spraying volume of approximately 2. 0 L m^2 is thinner and lighter than the TSAL,which can decrease the thickness and improve the bearing ability of the whole pavement structure.
基金Project(50235040) supported bythe National Natural Science Foundation of China project(NCET-040753) supported bythe New Century Excellent Talents in University project(20050533037) supported by the research fund for the Doctoral Program ofHigher Education
文摘Based on the harmonic vibration equation, the relationship between IR characteristic peak of fiberglass and Si-O-Si bond angle was deduced, and 1 100 cm^-1 characteristic peak was specifically studied. It is found that 1 100 cm^-1 characteristic peak shifts to higher wave number when Si-O-Si bond angle increases. Taking fused biconical taper (FBT) coupler as an example, the microstructures of the fiber coupler manufactured at different draw- ing speeds were tested with micro infrared spectrum. According to the test results, it is found that the bond angle at the taper region is the largest, the one at the fused region is the second largest, and the one of bare fiber is the smal- lest. The characteristic peaks of fused-taper region shift to higher wave number when drawing speed increases.
文摘In this paper, we investigate the properties of an alternative material for use in marine engineering, namely a rigid and light sandwich-structured composite made of expanded polystyrene and fiberglass. Not only does this material have an improved section modulus, but it is also inexpensive, light, easy to manipulate, and commercially available in various sizes. Using a computer program based on the finite element method, we calculated the hogging and sagging stresses and strains acting on a prismatic boat model composed of this material, and determined the minimum sizes and maximum permissible stresses to avoid deformation. Finally, we calculated the structural weight of the resulting vessel for comparison with another structure of comparable dimensions constructed from the commonly used core material Divinycell.
文摘AIM To determine if complete, split casts and backslabs [plaster of Paris(POP) and fiberglass] generate different intracast pressures and pain. METHODS Increased swelling within casts was modeled by a closed water system attached to an expandable bag placed directly under different types of casts applied to a healthy lower limb. Complete fiberglass and POP casts, split casts and backslabs were applied. Twenty-five milliliter aliquots of saline were injected into the system and the generated intracast pressures were measured using a sphygmomanometer. The subject was blinded to the pressure scores to avoid bias. All casts were applied to the same right limb on the same subject to avoid the effects of variations in anatomy or physiology on intracast pressures. Pain levels were evaluated using the Visual Analogue Score after each sequential saline injection. Each type of cast was reapplied four times and the measurements were repeated on four separate occasions. Sample sizes were determined by a pre-study 90% power calculation to detect a 20% difference in intracast pressures between cast groups. RESULTS A significant difference between the various types of casts was noted when the saline volume was greater than 100 mL(P = 0.009). The greatest intracast pressure was generated by complete fiberglass casts, which were significantly higher than complete POP casts or backslabs(P = 0.018 and P = 0.008 respectively) at intracast saline volumes of 100 mL and higher. Backslabs produced a significantly lower intracast pressure compared to complete POP only once the saline volume within casts exceeded 225 mL(P = 0.009). Intracast pressures were significantly lower in split casts(P = 0.003). Split POP and fiberglass casts produced the lowest intracast pressures, even compared to backslabs(P = 0.009). Complete fiberglass casts generated the highest pain levels at manometer pressures of 75 mm Hg and greater(P = 0.001). Split fiberglass casts had significantly reduced pain levels(P = 0.001). In contrast, a split complete POP cast did not produce significantly reduced pain levels at pressures between 25-150 mmH g. There was no difference in pain generated by complete POP and backslabs at manometer pressures of 200 mm Hg and lower. CONCLUSION Fibreglass casts generate significantly higher intracast pressures and pain than POP casts. Split casts cause lower intracast pressures regardless of material, than complete casts and backslabs.
文摘The emission of fine particulates from the burning of coal can pose a number of problems for human health and the environment.The bag filter is an equipment capable of preventing these particles from reaching the atmosphere.The present work evaluated and proposed improvements based on information received from a process of a company producing vegetable bran and oils,which acts with high emission of particulates.The filter sleeves used were fiberglass fabric with expanded polytetrafluoroethylene membrane.Physical,mechanical and granulometric laboratory analyzes were performed,as well as scanning electron microscopy and dispersive energy spectroscopy for the characterization of the tissue and particulate matter.Based on the results,a new specification of stainless steel cage was proposed for the filter in order to improve the efficiency of retention,as well as to increase the useful life of the filter elements.
文摘A new strategy to prevent the biofouling of water-submerged surfaces is presented here. In particular, the authors showthat carbonic anydrase from Methanosarcina thermophila can be entrapped into polyacrylic paints, preserving enzyme activity. In addition, the authors also show that enzyme-containing paints inhibit the growth of marine microorganims, preventing biofouling.
文摘The effect of modifying the surface of multiwall carbon nanotubes (CNT’s) by oxygen and nitrogen on the strength characteristics of the fiberglass filled with them was investigated by testing for tension and bending. The method of obtaining nitrogen-containing nanostructures is developed. It was shown that in the epoxide system LR285-LH286 hydrophobic CNT’s (outgoing) at introducing into the catalyst polymerization of LH286, increase the strength with respect to unreinforced CNT’s by 48% - 54%. Oxidized CNT’s (200 A?h/kg) introduced into the resin LR285 increase the strength by 59%. The distribution of the filler particles in size, both in the epoxy resin and in the catalyst, depends on their concentration nonlinear, and correlates with the strength characteristics of the composite.
文摘In this article,theoretical calculations on the bending performance(bending strength and bending modulus)of fiberglass reinforced plastic(FRP)honeycomb sandwich structures were conducted initially,and then the bending performance of two FRP honeycomb sandwich structures with different thicknesses were measured by the Aerospace Materials Failure Analysis Center.By comparing and analyzing the theoretical calculations and experimental results,it was found that the theoretical calculated bending strength and bending modulus were in good agreement with those of the experimental tested within 26.5%.When designers and technicians conduct theoretical calculations on the performance of FRP honeycomb sandwich structures,they can use the formulas derived in this article,which will more accurately predict the mechanical properties of components made of composite materials.
文摘The energy efficiency of a building depends on building envelope performance.The results presented in this paper are the first of a long-term building envelope research project at the Alternative Village at the University of Manitoba in Winnipeg,Manitoba,Canada.Five test buildings were constructed using the following systems:two wood frames with fiberglass batt insulation and dense pack cellulose,one polyurethane structural insulated panels(PUR SIP),and two with the Stay in place PVC concrete form building system using 102mm and 204mm of concrete externally insulated with 102mm of expanded polystyrene foam.All of the buildings had a common foundation and roof system with a footprint of 23.8 m2.Blower door tests were conducted to determine air tightness.Each structure was heated with an electrical resistance heater and maintained at a constant internal temperature.The thermal gradient through the wall and power consumption were monitored.The study period discussed in this report represents the main heating season from October 2011 to April 2012 consisting of 209 days.Based on the power consumption,the PUR SIP consumed the least at 2498 kWh,while the 204 mm Stay in place PVC concrete form building used the most at 2898 kWh for the same time period.The thermal gradient through the cross section of the wood frame structures was compared through the cavity insulation and at the stud.It was found that the cellulose building provided better thermal resistance along the stud when compared to the fiberglass batt insulation.
基金supported by Citrus Disease Research and Extension(CDRE)(grant no.2016-70016-24828/project accusation no.1008984)from the USDA National Institute of Food and Agriculture
文摘Intensification of pollution loading worldwide has promoted an escalation of different types of disease-causing microorganisms, such as harmful algal blooms(HABs), instigating detrimental impacts on the quality of receiving surface waters. Formation of unwanted disinfection by-products(DBPs) resulting from conventional disinfection technologies reveals the need for the development of new sustainable alternatives. Quaternary Ammonium Compounds(QACs) are cationic surfactants widely known for their effective biocidal properties at the ppm level. In this study, a novel silica-based antimicrobial nanofilm was developed using a composite of silica-modified QAC(Fixed-Quat) and applied to a fiberglass mesh as an active surface via sol–gel technique. The synthesized Fixed-Quat nanocoating was found to be effective against E. coli with an inactivation rate of 1.3 × 10^(-3) log reduction/cm min. The Fixed-Quat coated fiberglass mesh also demonstrated successful control of Microcystis aeruginosa with more than 99% inactivation after 10 hr of exposure.The developed antimicrobial mesh was also evaluated with wild-type microalgal species collected in a water body experiencing HABs, obtaining a 97% removal efficiency. Overall,the silica-functionalized Fixed-Quat nanocoating showed promising antimicrobial properties for water disinfection and HABs control, while decreasing concerns related to DBPs formation and the possible release of toxic nanomaterials into the environment.
文摘Biological structural fixed joints exhibit unique attributes, including highly optimized fiber paths which minimize stress concentrations. In addition, since the joints consist of continuous, uncut fiber architectures, the joints enable the organism to transport information and chemicals from one part of the body to the other. To the contrary, sections of man-made composite material structures are often joined using bolted or bonded joints, which involve low strength and high stress concentrations. These methods are also expensive to achieve. Additional functions such as fluid transport, electrical signal delivery, and thermal conductivity across the joints typically require parasitic tubes, wires, and attachment clips. By using the biomimetic methods, we seek to overcome the limitations which are present in the conventional methods. In the present work, biomimetic co-cured composite sandwich T-joints were constructed using unidirectional glass fiber, epoxy resin, and structural foam. The joints were fabricated using the wet lay-up vacuum bag resin infusion method. Foam sandwich T-joints with multiple continuous fiber architectures and sandwich foam thickness were prepared. The designs were tested in quasi-static bending using a mechanical load frame. The significant weight savings using the biomimetic approaches is discussed, as well as a comparison of failure modes versus architecture is described.
文摘Blanking is one of the high speed processes to produce fiat products from sheets economically. In order to expand this process to new materials, the blanking of polyvinyl chloride (PVC)/fiberglass thermoplastic com- posite laminates and composite/aluminum hybrid laminates was investigated. The laminates were produced by the film stacking procedure and then blanked by circular die and punches. The blanking process was done in two levels of clearance including 4% and 8% of the laminates thickness, two levels of punch speed including 40 mm/min and 200 mm/min and at two levels of temperature (room tem- perature and 80 ℃) for both composite and hybrid laminates. The effects of the parameters on the maximum blanking force, cutting energy, and quality and precision of sheared edges were studied. Cutting mechanism for blanking in different conditions was explained. It was concluded that at room temperature, blanked composite and hybrid laminates had a high quality of sheared edges but at elevated temperature, although the maximum blanking force was reduced, the quality of sheared edge was reduced significantly.