Effects of tie beam length, width and overlap stress on settlement of foundations have been investigated. In this investigation square concrete footings have been used with dimensions (B × B × d) where (d) i...Effects of tie beam length, width and overlap stress on settlement of foundations have been investigated. In this investigation square concrete footings have been used with dimensions (B × B × d) where (d) is footing depth and (B) is footing width (1, 1.5,2 m). Width of tie beam (b) has been taken equal to 0.25, 0.30, 0.40, 0.50 and 0.75 (m). Tie beam length (L) has been taken varying from B till 3B with same footing depth = 0.50 m. Effect of overlap stress on settlement as well as effect of tie beam width and length on settlement has been determined. Also, the efficiency of tie beam length and width has been obtained. An equation is presented to compute the overlap stress zone in case of existing tie beam. It is found that the settlement increases with increasing the length of tie beam which is clear after the effect of the overlap stresses zone. The width of overlap stress zone case of existing tie beam has been found to be equal to (1.6 -1.75) B. The settlement of footings decreases with increasing tie beam width. It is found that the settlement after the effect of the overlap stress zone increases with increasing the length of tie beam.展开更多
This work is aimed at studying the strengthening of reinforced concrete (R. C.) beams using prestressed glass fi- ber-reinforced polymer (PGFRP). Carbon fiber-reinforced polymer (CFRP) has recently become popular for ...This work is aimed at studying the strengthening of reinforced concrete (R. C.) beams using prestressed glass fi- ber-reinforced polymer (PGFRP). Carbon fiber-reinforced polymer (CFRP) has recently become popular for use as repair or rehabilitation material for deteriorated R. C. structures, but because CFRP material is very stiff, the difference in CFRP sheet and concrete material properties is not favorable for transferring the prestress from CFRP sheets to R. C. members. Glass fi- ber-reinforced polymer (GFRP) sheets with Modulus of Elasticity quite close to that of concrete was chosen in this study. The load-carrying capacities (ultimate loads) and the deflections of strengthened R. C. beams using GFRP and PGFRP sheets were tested and compared. T- and ⊥-shaped beams were used as the under-strengthened and over-strengthened beams. The GFRP sheets were prestressed to one-half their tensile capacities before being bonded to the T- and ⊥-shaped R. C. beams. The prestressed tension in the PGFRP sheets caused cambers in the R. C. beams without cracks on the tensile faces. The PGFRP sheets also enhanced the load-carrying capacity. The test results indicated that T-shaped beams with GFRP sheets increased in load-carrying capacity by 55% while the same beams with PGFRP sheets could increase load-carrying capacity by 100%. The ⊥-shaped beams with GFRP sheets could increase load-carrying capacity by 97% while the same beams with PGFRP sheets could increase the loading-carrying capacity by 117%. Under the same external loads, beams with GFRP sheets underwent larger deflections than beams with PGFRP sheets. While GFRP sheets strengthen R. C. beams, PGFRP sheets decrease the beams’ ductility, especially for the over-strengthened beams (⊥-shaped beams).展开更多
A method for strengthening concrete structures by prestressed intraply hybrid C/AFRP sheets(composed of aramid fiber and carbon fiber)is proposed,aiming at overcoming shortages of some current strengthening methods.Th...A method for strengthening concrete structures by prestressed intraply hybrid C/AFRP sheets(composed of aramid fiber and carbon fiber)is proposed,aiming at overcoming shortages of some current strengthening methods.The bending capacity of beams strengthened by prestressed intraply hybrid C/AFRP sheets is analysed.The result shows that the bending resistance,the extending performance and the economical efficiency of intraply hybrid fiber sheets are better than those of interlaminar hybrid fiber sheets and single-fiber sheets.Moreover,prestressed intraply hybrid C/AFRP sheets can improve the performance of the strengthened beam,effectively inhibit the expansion of the cracks,and reduce distortion and risk of early failure.展开更多
Strengthening reinforced concrete (R. C.) beams using prestressed glass fiber-reinforced polymer (PGFRP) was studied experimentally as described in Part I of this paper (Huang et al., 2005). In that paper, R. C. beams...Strengthening reinforced concrete (R. C.) beams using prestressed glass fiber-reinforced polymer (PGFRP) was studied experimentally as described in Part I of this paper (Huang et al., 2005). In that paper, R. C. beams, R. C. beams with GFRP (glass fiber-reinforced polymer) sheets, and R. C. beams with PGFRP sheets were tested in both under-strengthened and over-strengthened cases. The test results showed that the load-carrying capacities (ultimate loads) of the beams with GFRP sheets were greater than those of the beams without polymer sheets. The load-carrying capacities of beams with PGFRP sheets were greater than those of beams with GFRP sheets. The objective of this work is to develop an analytical method to compute all of these load-carrying capacities. This analytical method is independent of the experiments and based only on the traditional R. C. and P. C. (prestressed concrete) theory. The analytical results accorded with the test results. It is suggested that this analytical method be used for analyzing and designing R. C. beams strengthened using GFRP or PGFRP sheets.展开更多
B4C, SiC and C, Cu functionally graded-materials (FGMs) have been developed by plasma spraying and hot pressing. Their high-heat flux properties have been investigated by high energy laser and electron beam for the si...B4C, SiC and C, Cu functionally graded-materials (FGMs) have been developed by plasma spraying and hot pressing. Their high-heat flux properties have been investigated by high energy laser and electron beam for the simulation of plasma disruption process of the future fusion reactors, And a study on eroded products of B4C/Cu FGM under transient thermal load of electron beam was performed. In the experiment, SEM and EDS analysis indicated that B4C and SiC were decomposed, carbon was preferentially evaporated under high thermal load, and a part of Si and Cu were melted, in addition, the splash of melted metal and the particle emission of brittle destruction were also found. Different erosive behaviors of carbon-based materials (CBMs) caused by laser and electron beam were also discussed.展开更多
C ^＋ ion beam-assisted deposition was utilized to prepare deposit diamond-like carbon （ DLC ） film. With the help of a series of experiments such as Raman spectroscopy, FT-IR spectroscopy, AFM and nanoindentation ,...C ^＋ ion beam-assisted deposition was utilized to prepare deposit diamond-like carbon （ DLC ） film. With the help of a series of experiments such as Raman spectroscopy, FT-IR spectroscopy, AFM and nanoindentation , the DLC film has been recognized as hydrogenated DLC film and its tribologicul properties have been evaluated. The bull-on-disc testing results show that the hardness and the tribologicul properties of the DLC film produced by C^ ＋ ion beam- assisted deposition are improved significantly. DLC film produced by C ^＋ ion beam- assisted deposition is positive to have a prosperous tribologicul application in the near future.展开更多
In this study,a high-throughput screening method was established through the 24-square deep-well microliter plate(MTP) fermentation and micro-plate detection for large-scale screening of the mutants.It was suitable fo...In this study,a high-throughput screening method was established through the 24-square deep-well microliter plate(MTP) fermentation and micro-plate detection for large-scale screening of the mutants.It was suitable for screening a large number of mutants and improving the breeding efficiency after heavy-ion beam irradiation.Seventeen strains showed higher cellulase activity compared with the initial strain after the screening of plate and MTP fermentation.The filter paper activity and β-glucosidase activity of Aspergillus niger H11201 had increased 38.74 and 63.23%separately compared with A.niger H11 by shaking flask fermentation,and it was genetically stable after being passaged to nine generations.The results indicate that the high-throughput screening method can be used for the quick breeding of A.niger with high cellulase activity.展开更多
The feedback stabilization problem of a nonuniform Timoshenko beam system with rotor inertia at the tip of the beam is studied. First, as a special kind of linear boundary force feedback and moment control is applied ...The feedback stabilization problem of a nonuniform Timoshenko beam system with rotor inertia at the tip of the beam is studied. First, as a special kind of linear boundary force feedback and moment control is applied to the beam' s tip, the strict mathematical treatment,a suitable state Hilbert space is chosen, and the well-poseness of the corresponding closed loop system is proved by using the semigroup theory of bounded linear operators. Then the energy corresponding to the closed loop system is shown to be exponentially stable. Finally, in the special case of uniform beam,some sufficient and necessary conditions for the corresponding closed loop system to be asymptotically stable are derived.展开更多
-<sup>11</sup>C and <sup>17</sup>F secondary beams have been successfully tuned on the CIAE sec-ondary radioactive beam line at the HI-13 tandem accelerator.The setting parametersof the seconda...-<sup>11</sup>C and <sup>17</sup>F secondary beams have been successfully tuned on the CIAE sec-ondary radioactive beam line at the HI-13 tandem accelerator.The setting parametersof the secondary beam line and the beam quality for <sup>11</sup>C and <sup>17</sup>F are given.A <sup>11</sup>C beamis produced with intensity 1.2×10<sup>5</sup> particles/s and energy 41±1.0 MeV.展开更多
The stabilization of the Timoshenko equation of a nonuniform beam with locally distributed feedbacks is considered.It is proved that the system is exponentially stabilizable.The frequency domain method and the multipl...The stabilization of the Timoshenko equation of a nonuniform beam with locally distributed feedbacks is considered.It is proved that the system is exponentially stabilizable.The frequency domain method and the multiplier technique are applied.展开更多
文摘Effects of tie beam length, width and overlap stress on settlement of foundations have been investigated. In this investigation square concrete footings have been used with dimensions (B × B × d) where (d) is footing depth and (B) is footing width (1, 1.5,2 m). Width of tie beam (b) has been taken equal to 0.25, 0.30, 0.40, 0.50 and 0.75 (m). Tie beam length (L) has been taken varying from B till 3B with same footing depth = 0.50 m. Effect of overlap stress on settlement as well as effect of tie beam width and length on settlement has been determined. Also, the efficiency of tie beam length and width has been obtained. An equation is presented to compute the overlap stress zone in case of existing tie beam. It is found that the settlement increases with increasing the length of tie beam which is clear after the effect of the overlap stresses zone. The width of overlap stress zone case of existing tie beam has been found to be equal to (1.6 -1.75) B. The settlement of footings decreases with increasing tie beam width. It is found that the settlement after the effect of the overlap stress zone increases with increasing the length of tie beam.
文摘This work is aimed at studying the strengthening of reinforced concrete (R. C.) beams using prestressed glass fi- ber-reinforced polymer (PGFRP). Carbon fiber-reinforced polymer (CFRP) has recently become popular for use as repair or rehabilitation material for deteriorated R. C. structures, but because CFRP material is very stiff, the difference in CFRP sheet and concrete material properties is not favorable for transferring the prestress from CFRP sheets to R. C. members. Glass fi- ber-reinforced polymer (GFRP) sheets with Modulus of Elasticity quite close to that of concrete was chosen in this study. The load-carrying capacities (ultimate loads) and the deflections of strengthened R. C. beams using GFRP and PGFRP sheets were tested and compared. T- and ⊥-shaped beams were used as the under-strengthened and over-strengthened beams. The GFRP sheets were prestressed to one-half their tensile capacities before being bonded to the T- and ⊥-shaped R. C. beams. The prestressed tension in the PGFRP sheets caused cambers in the R. C. beams without cracks on the tensile faces. The PGFRP sheets also enhanced the load-carrying capacity. The test results indicated that T-shaped beams with GFRP sheets increased in load-carrying capacity by 55% while the same beams with PGFRP sheets could increase load-carrying capacity by 100%. The ⊥-shaped beams with GFRP sheets could increase load-carrying capacity by 97% while the same beams with PGFRP sheets could increase the loading-carrying capacity by 117%. Under the same external loads, beams with GFRP sheets underwent larger deflections than beams with PGFRP sheets. While GFRP sheets strengthen R. C. beams, PGFRP sheets decrease the beams’ ductility, especially for the over-strengthened beams (⊥-shaped beams).
基金Supported by the National Natural Science Foundation of China(11272147,10772078)the Priority Academic Porgram Development of Jiangsu Higher Education Institutions+2 种基金the Jiangsu Transportation Research Program Funded Projects(2012Y10)the Suqian Transportation Research Project(SQJTKY2012-09)the Open Foundation of State Key Laboratory of Mechanics and Control Mechanical Structures in Nanjing University of Aeronautics and Astronautics(XQA13007)
文摘A method for strengthening concrete structures by prestressed intraply hybrid C/AFRP sheets(composed of aramid fiber and carbon fiber)is proposed,aiming at overcoming shortages of some current strengthening methods.The bending capacity of beams strengthened by prestressed intraply hybrid C/AFRP sheets is analysed.The result shows that the bending resistance,the extending performance and the economical efficiency of intraply hybrid fiber sheets are better than those of interlaminar hybrid fiber sheets and single-fiber sheets.Moreover,prestressed intraply hybrid C/AFRP sheets can improve the performance of the strengthened beam,effectively inhibit the expansion of the cracks,and reduce distortion and risk of early failure.
文摘Strengthening reinforced concrete (R. C.) beams using prestressed glass fiber-reinforced polymer (PGFRP) was studied experimentally as described in Part I of this paper (Huang et al., 2005). In that paper, R. C. beams, R. C. beams with GFRP (glass fiber-reinforced polymer) sheets, and R. C. beams with PGFRP sheets were tested in both under-strengthened and over-strengthened cases. The test results showed that the load-carrying capacities (ultimate loads) of the beams with GFRP sheets were greater than those of the beams without polymer sheets. The load-carrying capacities of beams with PGFRP sheets were greater than those of beams with GFRP sheets. The objective of this work is to develop an analytical method to compute all of these load-carrying capacities. This analytical method is independent of the experiments and based only on the traditional R. C. and P. C. (prestressed concrete) theory. The analytical results accorded with the test results. It is suggested that this analytical method be used for analyzing and designing R. C. beams strengthened using GFRP or PGFRP sheets.
文摘B4C, SiC and C, Cu functionally graded-materials (FGMs) have been developed by plasma spraying and hot pressing. Their high-heat flux properties have been investigated by high energy laser and electron beam for the simulation of plasma disruption process of the future fusion reactors, And a study on eroded products of B4C/Cu FGM under transient thermal load of electron beam was performed. In the experiment, SEM and EDS analysis indicated that B4C and SiC were decomposed, carbon was preferentially evaporated under high thermal load, and a part of Si and Cu were melted, in addition, the splash of melted metal and the particle emission of brittle destruction were also found. Different erosive behaviors of carbon-based materials (CBMs) caused by laser and electron beam were also discussed.
基金Funded by the National Natural Science Foundation of China(No.50175041 ,50275111)
文摘C ^＋ ion beam-assisted deposition was utilized to prepare deposit diamond-like carbon （ DLC ） film. With the help of a series of experiments such as Raman spectroscopy, FT-IR spectroscopy, AFM and nanoindentation , the DLC film has been recognized as hydrogenated DLC film and its tribologicul properties have been evaluated. The bull-on-disc testing results show that the hardness and the tribologicul properties of the DLC film produced by C^ ＋ ion beam- assisted deposition are improved significantly. DLC film produced by C ^＋ ion beam- assisted deposition is positive to have a prosperous tribologicul application in the near future.
基金supported by the National Natural Science Foundation of China(No.11305225)the Science and Technology Service Network Initiative(KFJ-EW-STS-086)
文摘In this study,a high-throughput screening method was established through the 24-square deep-well microliter plate(MTP) fermentation and micro-plate detection for large-scale screening of the mutants.It was suitable for screening a large number of mutants and improving the breeding efficiency after heavy-ion beam irradiation.Seventeen strains showed higher cellulase activity compared with the initial strain after the screening of plate and MTP fermentation.The filter paper activity and β-glucosidase activity of Aspergillus niger H11201 had increased 38.74 and 63.23%separately compared with A.niger H11 by shaking flask fermentation,and it was genetically stable after being passaged to nine generations.The results indicate that the high-throughput screening method can be used for the quick breeding of A.niger with high cellulase activity.
基金This work was supported by the Science Foundation of China Geosciences University (Beijing) the National Natural Science Foundation of China ( No. 60174008).
文摘The feedback stabilization problem of a nonuniform Timoshenko beam system with rotor inertia at the tip of the beam is studied. First, as a special kind of linear boundary force feedback and moment control is applied to the beam' s tip, the strict mathematical treatment,a suitable state Hilbert space is chosen, and the well-poseness of the corresponding closed loop system is proved by using the semigroup theory of bounded linear operators. Then the energy corresponding to the closed loop system is shown to be exponentially stable. Finally, in the special case of uniform beam,some sufficient and necessary conditions for the corresponding closed loop system to be asymptotically stable are derived.
基金The project supported in part by National Natural Science Foundation of ChinaChina Nuclear Industry Science Foundation.
文摘-<sup>11</sup>C and <sup>17</sup>F secondary beams have been successfully tuned on the CIAE sec-ondary radioactive beam line at the HI-13 tandem accelerator.The setting parametersof the secondary beam line and the beam quality for <sup>11</sup>C and <sup>17</sup>F are given.A <sup>11</sup>C beamis produced with intensity 1.2×10<sup>5</sup> particles/s and energy 41±1.0 MeV.
基金Supported partially by the NSFC and the Science Foundation of China State Education Commission.
文摘The stabilization of the Timoshenko equation of a nonuniform beam with locally distributed feedbacks is considered.It is proved that the system is exponentially stabilizable.The frequency domain method and the multiplier technique are applied.
