New data from FRB’s have provided an exciting new window on the cosmos. For the first time we have both Dispersion Measure (DM) from distant sources and their red-shift. This gives us the opportunity to determine the...New data from FRB’s have provided an exciting new window on the cosmos. For the first time we have both Dispersion Measure (DM) from distant sources and their red-shift. This gives us the opportunity to determine the average electron number density in intergalactic space and thus test New Tired Light predictions. Here, in an alternative cosmology, the universe is static and redshifts are produced by an interaction between photons and the electrons in the intergalactic medium. In a paper published in summer 2006 New Tired Light (NTL) predicted an average electron number density of n = 0.5 m<sup>-3</sup>. In 2016 a paper was published reporting that for the first time the DM of a FRB and the redshift of the host galaxy had been found. Using standard physics this confirmed the electron number density as n = 0.5 m<sup>-3</sup>. The prediction NTL made ten years earlier was proved to be correct. Using this measured electron number density enabled a definitive value of the Hubble constant to be made by New Tired Light and the value is 63 km/s per Mpc which compares well with currently accepted values. Importantly, since in NTL the redshift and dispersion are both due to the electrons in IG space, a relationship between DM’s and redshift can be predicted. NTL predicts that DM and LN(1 + z) will be directly proportional and related by the formula DM = mec/2hr<sub>e</sub>(3.086 × 1022) where me, re are the rest mass and classical radius of the electron, c is the speed of light in a vacuum and h is the plank constant. The numerical term is to change units from pccm<sup>-3</sup> to m<sup>-2</sup>. This reduces to DM = 2380LN(1 + z). Using data from five FRB’s this is tested and a linear relation is seen of the form DM = 1830LN(1 + z). The gradient of the plot from the observed data is within 23% of that predicted by NTL. Recently the Tolman Surface Brightness test has been applied to the HUDF and the results support a static universe whilst the possibility of two differing types of SN Ia whose distribution changes with distances means that tired light models can no longer be ruled out. Using SDF we know the distance to the Atlia galaxy cluster as 1.26 × 10<sup>24</sup> m. With the average electron number density of n = 0.5 m<sup>-3</sup> found from the Dispersion Measures of the FRB’s, from first principles, New Tired Light gives a calculated predicted redshift of 0.0086. This compares well with the value found spectroscopically of 0.0087—a difference of approximately 1%. It is shown that if the energy transferred to a recoiling electron when a UV photon of wavelength λ = 5 × 10<sup>-8</sup> m interacts with it is emitted as a secondary photon that photon will have a wavelength of 2.2 mm— the wavelength at which the CMB curve peaks.展开更多
Objective:To determine if infants aged 6 to 15 months with frequent parent-reported nighttime awakenings require reduced parental aid during a week of diphenhydramine hydrochloride treatment and 2 and 4 weeks after it...Objective:To determine if infants aged 6 to 15 months with frequent parent-reported nighttime awakenings require reduced parental aid during a week of diphenhydramine hydrochloride treatment and 2 and 4 weeks after its discontinuation. Design:Double-blind,randomized,controlled clinical trial. Setting:The study was conducted from May 1,2004,through May 1,2005; patients were recruited nationally. Participants:Forty four participants aged 6 to 15months. Interventions:Placebo or diphenhydraminewas administered in infants 30 minutes before anticipated bedtime. Main Outcome Measures:The primary outcome was dichotomous:a parental report of improvement in the number of night awakenings requiring parental assistance during the intervention week,which ended on day 14.Secondary outcomes were improved sleep during the 2 weeks before days 29 and 43,parental overall happiness with sleep,and improved sleep latency. Results:On June 6,2005,the data safety monitoring board voted unanimously to stop the trial early because of lack of effectiveness of diphenhydramine over placebo. Only 1 of 22 children receiving diphenhydramine showed improvement compared with 3 of 22 receiving placebo.To reach the a priori determined sample size and have a positive outcome (ie,rejecting the null hypothesis),the trial would have needed to enroll 16 more participants in each arm,with 15 of the 16 in the diphenhydramine group and 0 of 16 in the placebo group improving. Conclusion:During 1 week of therapy and at follow-up 2 and 4 weeks later,diphenhydramine was no more effective than placebo in reducing nighttime awakening or improving overall parental happiness with sleep for infants.展开更多
Airless tires are essential for enhancing the safety,reliability,and convenience of maintenance of electric bicycles.Polyurethane(PU)is considered a promising candidate for such applications owing to its versatile pro...Airless tires are essential for enhancing the safety,reliability,and convenience of maintenance of electric bicycles.Polyurethane(PU)is considered a promising candidate for such applications owing to its versatile properties.However,their use is limited by insufficient heat resistance and excessive dynamic heat generation under cyclic loading.In this study,star-shaped trifunctional polypropylene glycerol(PPG3)was incorporated into conventional poly(tetramethylene glycol)(PTMG)and 4,4'-methylenediphenyl diisocyanate(MDI)-based systems to construct microporous star-shaped casting polyurethanes(SCPU),with water serving as a green foaming agent.Unlike conventional small-molecule trifunctional crosslinkers that create junctions within hard segment domains,PPG3 introduces long flexible arms between the hard segments,anchoring the crosslinking points at its molecular core.The large steric hindrance of PPG3 effectively suppresses soft segment crystallization and lowers the degree of microphase separation,whereas the crosslinked network restricts chain mobility,thereby reducing dynamic heat generation.These structural features also enhance the heat resistance,yielding a softening temperature of 183℃,which is 30.9%higher than that of polyurethane without PPG3.When applied to airless tires by casting SCPU into rubber treads,the fabricated hybrid airless tires achieved a rolling distance of over 3000 km under a load of 65 kg at 25km/h without structural failure,satisfying practical performance requirements.This strategy offers a simple,solvent-free,and environmentally friendly process,underscoring the potential of SCPU for scalable production of high-performance airless tires.展开更多
Retirement no longer equates with being old as many of the world’s younger generations expect to spend a prolonged period in that phase of their lives.What they aim to pursue is a more avant-garde lifestyle-"FIR...Retirement no longer equates with being old as many of the world’s younger generations expect to spend a prolonged period in that phase of their lives.What they aim to pursue is a more avant-garde lifestyle-"FIRE:"Financial Independence,Retire Early.展开更多
China has a long tradition of highlighting reading for children, but many of today's youngsters seem not to have developed a love of books Shoved into Cheng Qidi's room is a bulky bookcase, all three of its sh...China has a long tradition of highlighting reading for children, but many of today's youngsters seem not to have developed a love of books Shoved into Cheng Qidi's room is a bulky bookcase, all three of its shelves full of books sorted by their subjects. Dozens of books occupy most of the desk that's beside the bookcase, while on the wall is a poster of U.S. basketball star Allen Iverson.展开更多
本文让我们知道:当今之美国有1/3左右的人睡眠欠佳;1/10左右的人长期失眠。此文观点辩证,它认为:iron-deficiency anemia(缺铁性贫血)是造成疲劳的原因,而fatigue also can be caused by iron overload;hypothyroidism(甲状腺机能减退)...本文让我们知道:当今之美国有1/3左右的人睡眠欠佳;1/10左右的人长期失眠。此文观点辩证,它认为:iron-deficiency anemia(缺铁性贫血)是造成疲劳的原因,而fatigue also can be caused by iron overload;hypothyroidism(甲状腺机能减退)与hyperthyroidism(甲状腺机能亢进)均可能引起疲劳。最值得提及的是,在学习语言的同时,您是否感到本文的苦干观点颇具新意,对我们的健康与养身不乏可参考性。如:1.Go to bed only when you’re tired;if you’restill awake after 20 minutes or so,get up and read or watch TV until you feellike nodding off.2.在 Grief Reaction一节中,文章写道:it helps simply toknow that time is a healer.(此语借自英谚——Time is a great healer.时间是治愈创伤的良药)3.(情绪抑郁引起的疲劳的特征)Depression-fatigued people typ-ically lack motivation to do things they normally enjoy.4.Prematurely jumpingback into the swing of things can bring on a relapse.(译文可参见第 85,86注)此句不失为病(即使是感冒)后养身之良言。 文章罗列了“Why Am I So Tired”的 8个原因,其中第 4个原因是 SleepApnea(睡眠中呼吸暂停),而且该病患者may wake up hundreds of展开更多
ON October 25, 1995, 91-year-old Zhang Yun, lay quietly in the Beijing Hospital. She closed her eyes and ended a life that began in the early years of this century. Her death made her friends, colleagues and subordina...ON October 25, 1995, 91-year-old Zhang Yun, lay quietly in the Beijing Hospital. She closed her eyes and ended a life that began in the early years of this century. Her death made her friends, colleagues and subordinates shed tears.展开更多
GARMENT design may soundlike a sidetrack for someonewho majored in Russianlanguage and whose work experienceincludes more than ten years as ateacher.But it was a natural choice forWei Wenqiao,born into a family
Dispersion measure in an FRB’s signal is produced by the photons of the radio waves interacting with the free electrons in the IGM. In New Tired Light (NTL), redshifts are produced by the photons of light interacting...Dispersion measure in an FRB’s signal is produced by the photons of the radio waves interacting with the free electrons in the IGM. In New Tired Light (NTL), redshifts are produced by the photons of light interacting with these self-same electrons and so, one would expect a direct relationship between the DM of an FRB and the redshift of the host galaxy. However, workers in this field assume expansion and weight the DM by dividing it by the scale factor (1 + z) to allow for expansion. Once this weighting is removed, it was predicted back in 2016 (when the first FRB was localized) and later presented at a conference and published in the proceedings that, as more FRB’s were localized, a graph of DM versus ln(1 + z) would be a straight line of gradient (mec/2hre) or 7.32 × 1025 m−2 in SI units. The original paper had twenty-four data points but this has risen significantly to sixty-four useable FRB’s and so this corrigendum updates that paper so that all sixty-four are used. The data give a straight-line graph of gradient 7.12 × 1025 m−2, a difference of 3% from (mec/2hre) predicted nine years earlier.展开更多
Operating under the philosophy that play is a child's right,Anthill Creations,a non‑profit run by Pooja Rai,has so far built 283 different play spaces using almost entirely painted tires,featuring large tire sculp...Operating under the philosophy that play is a child's right,Anthill Creations,a non‑profit run by Pooja Rai,has so far built 283 different play spaces using almost entirely painted tires,featuring large tire sculptures of cars,buildings or animals,paired with more classic elements of swings,see‑saws and jungle gyms.展开更多
Multi-axle Swerve-drive Autonomous Mobile Robots(MS-AMRs)equipped with independently steerable wheels are commonly used for high-payload transportation.In this work,we present a novel Model Predictive Control(MPC)meth...Multi-axle Swerve-drive Autonomous Mobile Robots(MS-AMRs)equipped with independently steerable wheels are commonly used for high-payload transportation.In this work,we present a novel Model Predictive Control(MPC)method for MS-AGV trajectory tracking that takes tire wear minimization consideration in the objective function.To speed up the problem-solving process,we propose a hierarchical controller design and simplify the dynamic model by integrating the magic formula tire model and simplified tire wear model.In the experiment,the proposed method can be solved by simulated annealing in real-time on a normal personal computer and by incorporating tire wear into the objective function,tire wear is reduced by 19.19%while maintaining the tracking accuracy in curve-tracking experiments.In the more challenging scene:the desired trajectory is offset by 60 degrees from the vehicle's heading,the reduction in tire wear increased to 65.20%compared to the kinematic model without considering the tire wear optimization.展开更多
Title:Seismic fragility of unreinforced masonry buildings with bonded scrap tire rubber isolators under far-field and near-field earthquakes Authors:WANG Mingyang;GAO Wenjun;LU Xilin;SHI Weixing A bstract:To improve t...Title:Seismic fragility of unreinforced masonry buildings with bonded scrap tire rubber isolators under far-field and near-field earthquakes Authors:WANG Mingyang;GAO Wenjun;LU Xilin;SHI Weixing A bstract:To improve the seismic performance of unreinforced masonry(URM)buildings in the Himalayan regions,including Western China,India,Nepal,and Pakistan,a low-cost bonded scrap tire rubber isolator(BSTRI)is proposed,and a series of vertical compression and horizontal shear tests are conducted.Incremental dynamic analyses are conducted for five types of BSTRI-supported URM buildings subjected to 22 far-field and 28 near-field earthquake ground motions.The resulting fragility curves and probability of damage curves are presented and utilized to evaluate the damage states of these buildings.The results show that in the base-isolated(BI)URM buildings under seismic ground motion at a peak ground acceleration(PGA)of 1.102 g,the probability of exceeding the collapse prevention threshold is less than 25%under far-field earthquake ground motions and 31%under near-field earthquake ground motions.Furthermore,the maximum average vulnerability index for the BI-URM buildings,which are designed to withstand rare earthquakes with 9°(PGA=0.632 g),is 40.87%for far-field earthquake ground motions and 41.83%for near-field earthquake ground motions.Therefore,the adoption of BSTRIs can significantly reduce the collapse probability of URM buildings.展开更多
Non-metallic inclusions are a significant factor causing fractures during the manufacturing process of tire cord steel,and dissolution in the steel profoundly affects them.How the basicity and Al_(2)O_(3) content in S...Non-metallic inclusions are a significant factor causing fractures during the manufacturing process of tire cord steel,and dissolution in the steel profoundly affects them.How the basicity and Al_(2)O_(3) content in SiO_(2)-CaO-Al_(2)O_(3)-MgO refining slag affect non-metallic inclusions in tire cord steel at 1873 K was investigated.A quantitative relationship has been established between the slag basicity and the dissolved oxygen content in steel.The results demonstrate that non-metallic inclusions in steel transform along SiO_(2)-MnO-Al_(2)O_(3)→SiO_(2)-MnO system of inclusions.When the basicity is controlled within the range of 0.8-1.0,the corresponding dissolved oxygen content should be between 4×10^(−6) and 10×10^(−6).When Al_(2)O_(3) content in the refining slag is maintained at 5%,and the slag basicity is controlled between 0.8 and 1.0,or if the slag basicity is precisely 1.0 with Al_(2)O_(3) content kept below 11%,control over the plasticization of SiO_(2)-MnO-Al_(2)O_(3) system within the inclusions can be effectively achieved.Combined with thermodynamic calculation and measurement of the dissolved oxygen([O])activity in the steel,controlling SiO_(2)-MnO-Al_(2)O_(3)-like inclusions in the plastic region range can be achieved by adjusting the refining slag composition.展开更多
In this paper,the pyrolysis characteristics of waste tire rubber with catalyst addition were experimentally studied.Pyrolysis experimentations of waste tire rubber with either base,acid or Zeolite catalysts were perfo...In this paper,the pyrolysis characteristics of waste tire rubber with catalyst addition were experimentally studied.Pyrolysis experimentations of waste tire rubber with either base,acid or Zeolite catalysts were performed in a Thermal Gravimetric Analyzer,a one-stage test rig and a two-stage test rig respectively.This is followed by analysis into the rates of pyrolysis reactions and the yields and distribution of the three-phase products using thermogravimetric infrared spectroscopy(TG-IR)and gas chromatographymass spectrometry(GC-MS).Results indicated that the transition metal chloride catalysts improved the reaction rate and were overall effective than the solid acid-base catalysts.Benzene and toluene yields were improved by all three catalysts in the primary pyrolysis,and the best performance was achieved at 550℃ and 600℃ with 30%NaOH.With ZSM-5 in the secondary pyrolysis,proportion of high calorific gases components as H2 and CH4 were increased,and the arylation and isomerization reactions were also promoted.The optimum aromatics yield was achieved at 600℃ and 50%ZSM condition.This study would provide a reference for resourceful utilization of waste tires.展开更多
To thoroughly examine the complex relationships between tire and pavement vibrations,a sophisticated vehicle-pavement coupled system is proposed,incorporating a non-uniform dynamic friction force between the tire and ...To thoroughly examine the complex relationships between tire and pavement vibrations,a sophisticated vehicle-pavement coupled system is proposed,incorporating a non-uniform dynamic friction force between the tire and the pavement.According to the Timoshenko beam theory,a dynamic model of pavement structure with a finite length beam was formulated on a nonlinear Pasternak foundation.To more accurately describe the coupling relationship between the tire and the pavement,and to take into account the vibration state under vehicle-pavement interaction,the load distribution between the tire and the pavement is modeled as a dynamic non-uniform contact.Combined with the classic LuGre tire model,the adhesion between the tire and the pavement is calculated.The Galerkin truncation method is employed to transform the pavement vibration partial differential equation into a finite ordinary differential equation,and the integral expression of the nonlinear foundation beam term is derived using the product to sum formula.By using the Runge-Kutta method,the tire-road coupled system can be numerically calculated,thus determining tire adhesion.This research demonstrates that compared with tire force under the traditional static load distribution,load distribution has a significant influence on adhesion.This study offers valuable insights for pavement structure design and vehicle performance control.展开更多
This study presents a fragility curve to assess explosively induced damage to military vehicle tires based on shock tube experiments.To replicate lateral damage scenarios that may occur in real battlefield environment...This study presents a fragility curve to assess explosively induced damage to military vehicle tires based on shock tube experiments.To replicate lateral damage scenarios that may occur in real battlefield environments involving missile or bomb detonations,extreme overpressure conditions were generated using a shock tube.The influence of explosive charge mass on tire damage was quantitatively evaluated.Experimental results identified two critical failure thresholds:for loss of pressure,the threshold was 354 kPa peak overpressure and 3052 kPa·ms impulse;for rupture,the values were 485 kPa and 4237 kPa-ms,respectively.The same damage profile was reproduced through finite element analysis(FEA),verifying the reliability of the simulation.A Single Degree of Freedom(SDOF)model and Kingery-Bulmash(K-B)chart were employed to generate pressure-impulse data as a function of standoff distance.These data were applied to a finite element tire model using the BLAST ENHANCED keyword in LS-DYNA.The applied peak overpressures were identical to the experimental values with a 24%-27%difference in impulse.The simulation also captured recurring bead rim separation phenomenon,leading to internal pressure loss consistent with high-speed camera observations from the experiments.The resulting fragility curve clearly defines the threshold conditions for tire damage and provides a standardized damage assessment model applicable to various explosive charge masses and stand-off distances.The proposed model offers a quantitative basis for evaluating tire vulnerability,providing foundational reference data for defense applications.Specifically,the findings are expected to serve as a reliable source for weapon effects analysis and target vulnerability assessments involving wheeled military vehicles.展开更多
The spoke as a key component has a significant impact on the performance of the non-pneumatic tire(NPT).The current research has focused on adjusting spoke structures to improve the single performance of NPT.Few studi...The spoke as a key component has a significant impact on the performance of the non-pneumatic tire(NPT).The current research has focused on adjusting spoke structures to improve the single performance of NPT.Few studies have been conducted to synergistically improve multi-performance by optimizing the spoke structure.Inspired by the concept of functionally gradient structures,this paper introduces a functionally gradient honeycomb NPT and its optimization method.Firstly,this paper completes the parameterization of the honeycomb spoke structure and establishes the numerical models of honeycomb NPTs with seven different gradients.Subsequently,the accuracy of the numerical models is verified using experimental methods.Then,the static and dynamic characteristics of these gradient honeycomb NPTs are thoroughly examined by using the finite element method.The findings highlight that the gradient structure of NPT-3 has superior performance.Building upon this,the study investigates the effects of key parameters,such as honeycomb spoke thickness and length,on load-carrying capacity,honeycomb spoke stress and mass.Finally,a multi-objective optimization method is proposed that uses a response surface model(RSM)and the Nondominated Sorting Genetic Algorithm-II(NSGA-II)to further optimize the functional gradient honeycomb NPTs.The optimized NPT-OP shows a 23.48%reduction in radial stiffness,8.95%reduction in maximum spoke stress and 16.86%reduction in spoke mass compared to the initial NPT-1.The damping characteristics of the NPT-OP have also been improved.The results offer a theoretical foundation and technical methodology for the structural design and optimization of gradient honeycomb NPTs.展开更多
文摘New data from FRB’s have provided an exciting new window on the cosmos. For the first time we have both Dispersion Measure (DM) from distant sources and their red-shift. This gives us the opportunity to determine the average electron number density in intergalactic space and thus test New Tired Light predictions. Here, in an alternative cosmology, the universe is static and redshifts are produced by an interaction between photons and the electrons in the intergalactic medium. In a paper published in summer 2006 New Tired Light (NTL) predicted an average electron number density of n = 0.5 m<sup>-3</sup>. In 2016 a paper was published reporting that for the first time the DM of a FRB and the redshift of the host galaxy had been found. Using standard physics this confirmed the electron number density as n = 0.5 m<sup>-3</sup>. The prediction NTL made ten years earlier was proved to be correct. Using this measured electron number density enabled a definitive value of the Hubble constant to be made by New Tired Light and the value is 63 km/s per Mpc which compares well with currently accepted values. Importantly, since in NTL the redshift and dispersion are both due to the electrons in IG space, a relationship between DM’s and redshift can be predicted. NTL predicts that DM and LN(1 + z) will be directly proportional and related by the formula DM = mec/2hr<sub>e</sub>(3.086 × 1022) where me, re are the rest mass and classical radius of the electron, c is the speed of light in a vacuum and h is the plank constant. The numerical term is to change units from pccm<sup>-3</sup> to m<sup>-2</sup>. This reduces to DM = 2380LN(1 + z). Using data from five FRB’s this is tested and a linear relation is seen of the form DM = 1830LN(1 + z). The gradient of the plot from the observed data is within 23% of that predicted by NTL. Recently the Tolman Surface Brightness test has been applied to the HUDF and the results support a static universe whilst the possibility of two differing types of SN Ia whose distribution changes with distances means that tired light models can no longer be ruled out. Using SDF we know the distance to the Atlia galaxy cluster as 1.26 × 10<sup>24</sup> m. With the average electron number density of n = 0.5 m<sup>-3</sup> found from the Dispersion Measures of the FRB’s, from first principles, New Tired Light gives a calculated predicted redshift of 0.0086. This compares well with the value found spectroscopically of 0.0087—a difference of approximately 1%. It is shown that if the energy transferred to a recoiling electron when a UV photon of wavelength λ = 5 × 10<sup>-8</sup> m interacts with it is emitted as a secondary photon that photon will have a wavelength of 2.2 mm— the wavelength at which the CMB curve peaks.
文摘Objective:To determine if infants aged 6 to 15 months with frequent parent-reported nighttime awakenings require reduced parental aid during a week of diphenhydramine hydrochloride treatment and 2 and 4 weeks after its discontinuation. Design:Double-blind,randomized,controlled clinical trial. Setting:The study was conducted from May 1,2004,through May 1,2005; patients were recruited nationally. Participants:Forty four participants aged 6 to 15months. Interventions:Placebo or diphenhydraminewas administered in infants 30 minutes before anticipated bedtime. Main Outcome Measures:The primary outcome was dichotomous:a parental report of improvement in the number of night awakenings requiring parental assistance during the intervention week,which ended on day 14.Secondary outcomes were improved sleep during the 2 weeks before days 29 and 43,parental overall happiness with sleep,and improved sleep latency. Results:On June 6,2005,the data safety monitoring board voted unanimously to stop the trial early because of lack of effectiveness of diphenhydramine over placebo. Only 1 of 22 children receiving diphenhydramine showed improvement compared with 3 of 22 receiving placebo.To reach the a priori determined sample size and have a positive outcome (ie,rejecting the null hypothesis),the trial would have needed to enroll 16 more participants in each arm,with 15 of the 16 in the diphenhydramine group and 0 of 16 in the placebo group improving. Conclusion:During 1 week of therapy and at follow-up 2 and 4 weeks later,diphenhydramine was no more effective than placebo in reducing nighttime awakening or improving overall parental happiness with sleep for infants.
基金financially supported by the National Natural Science Foundation of China(No.52303063)Hubei Provincial Department of Education Guided Scientific Research Project(No.B2024056)。
文摘Airless tires are essential for enhancing the safety,reliability,and convenience of maintenance of electric bicycles.Polyurethane(PU)is considered a promising candidate for such applications owing to its versatile properties.However,their use is limited by insufficient heat resistance and excessive dynamic heat generation under cyclic loading.In this study,star-shaped trifunctional polypropylene glycerol(PPG3)was incorporated into conventional poly(tetramethylene glycol)(PTMG)and 4,4'-methylenediphenyl diisocyanate(MDI)-based systems to construct microporous star-shaped casting polyurethanes(SCPU),with water serving as a green foaming agent.Unlike conventional small-molecule trifunctional crosslinkers that create junctions within hard segment domains,PPG3 introduces long flexible arms between the hard segments,anchoring the crosslinking points at its molecular core.The large steric hindrance of PPG3 effectively suppresses soft segment crystallization and lowers the degree of microphase separation,whereas the crosslinked network restricts chain mobility,thereby reducing dynamic heat generation.These structural features also enhance the heat resistance,yielding a softening temperature of 183℃,which is 30.9%higher than that of polyurethane without PPG3.When applied to airless tires by casting SCPU into rubber treads,the fabricated hybrid airless tires achieved a rolling distance of over 3000 km under a load of 65 kg at 25km/h without structural failure,satisfying practical performance requirements.This strategy offers a simple,solvent-free,and environmentally friendly process,underscoring the potential of SCPU for scalable production of high-performance airless tires.
文摘Retirement no longer equates with being old as many of the world’s younger generations expect to spend a prolonged period in that phase of their lives.What they aim to pursue is a more avant-garde lifestyle-"FIRE:"Financial Independence,Retire Early.
文摘China has a long tradition of highlighting reading for children, but many of today's youngsters seem not to have developed a love of books Shoved into Cheng Qidi's room is a bulky bookcase, all three of its shelves full of books sorted by their subjects. Dozens of books occupy most of the desk that's beside the bookcase, while on the wall is a poster of U.S. basketball star Allen Iverson.
文摘本文让我们知道:当今之美国有1/3左右的人睡眠欠佳;1/10左右的人长期失眠。此文观点辩证,它认为:iron-deficiency anemia(缺铁性贫血)是造成疲劳的原因,而fatigue also can be caused by iron overload;hypothyroidism(甲状腺机能减退)与hyperthyroidism(甲状腺机能亢进)均可能引起疲劳。最值得提及的是,在学习语言的同时,您是否感到本文的苦干观点颇具新意,对我们的健康与养身不乏可参考性。如:1.Go to bed only when you’re tired;if you’restill awake after 20 minutes or so,get up and read or watch TV until you feellike nodding off.2.在 Grief Reaction一节中,文章写道:it helps simply toknow that time is a healer.(此语借自英谚——Time is a great healer.时间是治愈创伤的良药)3.(情绪抑郁引起的疲劳的特征)Depression-fatigued people typ-ically lack motivation to do things they normally enjoy.4.Prematurely jumpingback into the swing of things can bring on a relapse.(译文可参见第 85,86注)此句不失为病(即使是感冒)后养身之良言。 文章罗列了“Why Am I So Tired”的 8个原因,其中第 4个原因是 SleepApnea(睡眠中呼吸暂停),而且该病患者may wake up hundreds of
文摘ON October 25, 1995, 91-year-old Zhang Yun, lay quietly in the Beijing Hospital. She closed her eyes and ended a life that began in the early years of this century. Her death made her friends, colleagues and subordinates shed tears.
文摘GARMENT design may soundlike a sidetrack for someonewho majored in Russianlanguage and whose work experienceincludes more than ten years as ateacher.But it was a natural choice forWei Wenqiao,born into a family
文摘Dispersion measure in an FRB’s signal is produced by the photons of the radio waves interacting with the free electrons in the IGM. In New Tired Light (NTL), redshifts are produced by the photons of light interacting with these self-same electrons and so, one would expect a direct relationship between the DM of an FRB and the redshift of the host galaxy. However, workers in this field assume expansion and weight the DM by dividing it by the scale factor (1 + z) to allow for expansion. Once this weighting is removed, it was predicted back in 2016 (when the first FRB was localized) and later presented at a conference and published in the proceedings that, as more FRB’s were localized, a graph of DM versus ln(1 + z) would be a straight line of gradient (mec/2hre) or 7.32 × 1025 m−2 in SI units. The original paper had twenty-four data points but this has risen significantly to sixty-four useable FRB’s and so this corrigendum updates that paper so that all sixty-four are used. The data give a straight-line graph of gradient 7.12 × 1025 m−2, a difference of 3% from (mec/2hre) predicted nine years earlier.
文摘Operating under the philosophy that play is a child's right,Anthill Creations,a non‑profit run by Pooja Rai,has so far built 283 different play spaces using almost entirely painted tires,featuring large tire sculptures of cars,buildings or animals,paired with more classic elements of swings,see‑saws and jungle gyms.
基金supported by the National Research Foundation,Singapore,under its Medium-Sized Center for Advanced Robotics Technology Innovation(CARTIN)。
文摘Multi-axle Swerve-drive Autonomous Mobile Robots(MS-AMRs)equipped with independently steerable wheels are commonly used for high-payload transportation.In this work,we present a novel Model Predictive Control(MPC)method for MS-AGV trajectory tracking that takes tire wear minimization consideration in the objective function.To speed up the problem-solving process,we propose a hierarchical controller design and simplify the dynamic model by integrating the magic formula tire model and simplified tire wear model.In the experiment,the proposed method can be solved by simulated annealing in real-time on a normal personal computer and by incorporating tire wear into the objective function,tire wear is reduced by 19.19%while maintaining the tracking accuracy in curve-tracking experiments.In the more challenging scene:the desired trajectory is offset by 60 degrees from the vehicle's heading,the reduction in tire wear increased to 65.20%compared to the kinematic model without considering the tire wear optimization.
文摘Title:Seismic fragility of unreinforced masonry buildings with bonded scrap tire rubber isolators under far-field and near-field earthquakes Authors:WANG Mingyang;GAO Wenjun;LU Xilin;SHI Weixing A bstract:To improve the seismic performance of unreinforced masonry(URM)buildings in the Himalayan regions,including Western China,India,Nepal,and Pakistan,a low-cost bonded scrap tire rubber isolator(BSTRI)is proposed,and a series of vertical compression and horizontal shear tests are conducted.Incremental dynamic analyses are conducted for five types of BSTRI-supported URM buildings subjected to 22 far-field and 28 near-field earthquake ground motions.The resulting fragility curves and probability of damage curves are presented and utilized to evaluate the damage states of these buildings.The results show that in the base-isolated(BI)URM buildings under seismic ground motion at a peak ground acceleration(PGA)of 1.102 g,the probability of exceeding the collapse prevention threshold is less than 25%under far-field earthquake ground motions and 31%under near-field earthquake ground motions.Furthermore,the maximum average vulnerability index for the BI-URM buildings,which are designed to withstand rare earthquakes with 9°(PGA=0.632 g),is 40.87%for far-field earthquake ground motions and 41.83%for near-field earthquake ground motions.Therefore,the adoption of BSTRIs can significantly reduce the collapse probability of URM buildings.
基金supported by the National Natural Science Foundation of China(Nos.52274337,52174317 and U1960203)2023 Liaoning Province Department of Education Fundamental Research Project Achievements(No.JYTMS20230928).
文摘Non-metallic inclusions are a significant factor causing fractures during the manufacturing process of tire cord steel,and dissolution in the steel profoundly affects them.How the basicity and Al_(2)O_(3) content in SiO_(2)-CaO-Al_(2)O_(3)-MgO refining slag affect non-metallic inclusions in tire cord steel at 1873 K was investigated.A quantitative relationship has been established between the slag basicity and the dissolved oxygen content in steel.The results demonstrate that non-metallic inclusions in steel transform along SiO_(2)-MnO-Al_(2)O_(3)→SiO_(2)-MnO system of inclusions.When the basicity is controlled within the range of 0.8-1.0,the corresponding dissolved oxygen content should be between 4×10^(−6) and 10×10^(−6).When Al_(2)O_(3) content in the refining slag is maintained at 5%,and the slag basicity is controlled between 0.8 and 1.0,or if the slag basicity is precisely 1.0 with Al_(2)O_(3) content kept below 11%,control over the plasticization of SiO_(2)-MnO-Al_(2)O_(3) system within the inclusions can be effectively achieved.Combined with thermodynamic calculation and measurement of the dissolved oxygen([O])activity in the steel,controlling SiO_(2)-MnO-Al_(2)O_(3)-like inclusions in the plastic region range can be achieved by adjusting the refining slag composition.
基金the Chongqing Municipal Education Commission Research Project(KJZD-K202401502)Chongqing Municipal Science&Technology Commission Research Project(CSTB2022NSCQ-LZX0071)to the research work.
文摘In this paper,the pyrolysis characteristics of waste tire rubber with catalyst addition were experimentally studied.Pyrolysis experimentations of waste tire rubber with either base,acid or Zeolite catalysts were performed in a Thermal Gravimetric Analyzer,a one-stage test rig and a two-stage test rig respectively.This is followed by analysis into the rates of pyrolysis reactions and the yields and distribution of the three-phase products using thermogravimetric infrared spectroscopy(TG-IR)and gas chromatographymass spectrometry(GC-MS).Results indicated that the transition metal chloride catalysts improved the reaction rate and were overall effective than the solid acid-base catalysts.Benzene and toluene yields were improved by all three catalysts in the primary pyrolysis,and the best performance was achieved at 550℃ and 600℃ with 30%NaOH.With ZSM-5 in the secondary pyrolysis,proportion of high calorific gases components as H2 and CH4 were increased,and the arylation and isomerization reactions were also promoted.The optimum aromatics yield was achieved at 600℃ and 50%ZSM condition.This study would provide a reference for resourceful utilization of waste tires.
基金financially supported by the National Natural Science Foundation of China(Grant No.12072204).
文摘To thoroughly examine the complex relationships between tire and pavement vibrations,a sophisticated vehicle-pavement coupled system is proposed,incorporating a non-uniform dynamic friction force between the tire and the pavement.According to the Timoshenko beam theory,a dynamic model of pavement structure with a finite length beam was formulated on a nonlinear Pasternak foundation.To more accurately describe the coupling relationship between the tire and the pavement,and to take into account the vibration state under vehicle-pavement interaction,the load distribution between the tire and the pavement is modeled as a dynamic non-uniform contact.Combined with the classic LuGre tire model,the adhesion between the tire and the pavement is calculated.The Galerkin truncation method is employed to transform the pavement vibration partial differential equation into a finite ordinary differential equation,and the integral expression of the nonlinear foundation beam term is derived using the product to sum formula.By using the Runge-Kutta method,the tire-road coupled system can be numerically calculated,thus determining tire adhesion.This research demonstrates that compared with tire force under the traditional static load distribution,load distribution has a significant influence on adhesion.This study offers valuable insights for pavement structure design and vehicle performance control.
基金part of the Agency for Defense Development(ADD)research project on Weapon lethality/effectiveness analysis technology for material targets and grant funded by the korean goverment(511225-912A03301)。
文摘This study presents a fragility curve to assess explosively induced damage to military vehicle tires based on shock tube experiments.To replicate lateral damage scenarios that may occur in real battlefield environments involving missile or bomb detonations,extreme overpressure conditions were generated using a shock tube.The influence of explosive charge mass on tire damage was quantitatively evaluated.Experimental results identified two critical failure thresholds:for loss of pressure,the threshold was 354 kPa peak overpressure and 3052 kPa·ms impulse;for rupture,the values were 485 kPa and 4237 kPa-ms,respectively.The same damage profile was reproduced through finite element analysis(FEA),verifying the reliability of the simulation.A Single Degree of Freedom(SDOF)model and Kingery-Bulmash(K-B)chart were employed to generate pressure-impulse data as a function of standoff distance.These data were applied to a finite element tire model using the BLAST ENHANCED keyword in LS-DYNA.The applied peak overpressures were identical to the experimental values with a 24%-27%difference in impulse.The simulation also captured recurring bead rim separation phenomenon,leading to internal pressure loss consistent with high-speed camera observations from the experiments.The resulting fragility curve clearly defines the threshold conditions for tire damage and provides a standardized damage assessment model applicable to various explosive charge masses and stand-off distances.The proposed model offers a quantitative basis for evaluating tire vulnerability,providing foundational reference data for defense applications.Specifically,the findings are expected to serve as a reliable source for weapon effects analysis and target vulnerability assessments involving wheeled military vehicles.
基金Supported by National Natural Science Foundation of China(Grant Nos.52072156,52272366)Postdoctoral Foundation of China(Grant No.2020M682269).
文摘The spoke as a key component has a significant impact on the performance of the non-pneumatic tire(NPT).The current research has focused on adjusting spoke structures to improve the single performance of NPT.Few studies have been conducted to synergistically improve multi-performance by optimizing the spoke structure.Inspired by the concept of functionally gradient structures,this paper introduces a functionally gradient honeycomb NPT and its optimization method.Firstly,this paper completes the parameterization of the honeycomb spoke structure and establishes the numerical models of honeycomb NPTs with seven different gradients.Subsequently,the accuracy of the numerical models is verified using experimental methods.Then,the static and dynamic characteristics of these gradient honeycomb NPTs are thoroughly examined by using the finite element method.The findings highlight that the gradient structure of NPT-3 has superior performance.Building upon this,the study investigates the effects of key parameters,such as honeycomb spoke thickness and length,on load-carrying capacity,honeycomb spoke stress and mass.Finally,a multi-objective optimization method is proposed that uses a response surface model(RSM)and the Nondominated Sorting Genetic Algorithm-II(NSGA-II)to further optimize the functional gradient honeycomb NPTs.The optimized NPT-OP shows a 23.48%reduction in radial stiffness,8.95%reduction in maximum spoke stress and 16.86%reduction in spoke mass compared to the initial NPT-1.The damping characteristics of the NPT-OP have also been improved.The results offer a theoretical foundation and technical methodology for the structural design and optimization of gradient honeycomb NPTs.
