Experimental Study and Fragility Analysis of Effective-Length Factors in Column Buckling

The design of columns relies heavily on the basis of Leonhard Euler’s Theory of Elastic Buckling.However,to increase the accuracy in determining the maximum critical load a column can withstand before buckling,a constant was introduced.This dimensionless coefficient is K,also known as the effective-length factor.This constant is often found in building design codes and varies in value depending on the type of column support that is applied.This paper presents experimental and analytical studies on the determination of the effective-length factor in the buckling stability of columns with partially-fixed support conditions.To this end,the accurate K value of the columns tested by the Instron Testing Machine(ITM)at California State University,Northridge’s(CSUN’s)Mechanics Laboratory is determined.The ITM is used in studying the buckling of columns where the supports are neither pinned nor fixed,and the material cross-section rather rests upon the machine while loading is applied axially.Several column specimens were tested and the experimental data were analyzed in order to estimation of the accurate effective-length factor.The calculations from the tested results as well as the conducted probabilistic analysis shed light on how a fragility curve may aid in predicting the effective-length value of future tests.

Minimal length effects on motion of a particle in Rindler space

Various quantum theories of gravity predict the existence of a minimal measurable length.In this paper,we study effects of the minimal length on the motion of a particle in the Rindler space under a harmonic potential.This toy model captures key features of particle dynamics near a black hole horizon and allows us to make three observations.First,we find that chaotic behavior becomes stronger with increases in minimal length effects,leading predominantly to growth in the maximum Lyapunov characteristic exponents,while the KAM curves on Poincarésurfaces of a section tend to disintegrate into chaotic layers.Second,in the presence of the minimal length effects,it can take a finite amount of Rindler time for a particle to cross the Rindler horizon,which implies a shorter scrambling time of black holes.Finally,the model shows that some Lyapunov characteristic exponents can be greater than the surface gravity of the horizon,violating the recently conjectured universal upper bound.In short,our results reveal that quantum gravity effects may make black holes prone to more chaos and faster scrambling.

Evaluation and Analysis of Packet-Length Effect on Networks-on-Chip

The network-on-chip （NoC） design methodology is an important trend for large system-on-chip designs to reduce the bandwidth and power constraints in traditional synchronous bus architectures. In the design of packet-based NoC, the packet-length plays an important role in the NoC throughput, latency, and energy consumption. The appropriate NoC packet-length was selected based on simulation and analysis of the packet-length effect on NoC for variable average data block length （ADBL） configuration parameters. A trade-off curve among throughput, latency, and energy consumption was developed and shows that the optimum packet length increases as the ADBL increases.

On the Determination and Characteristics of Effective Roughness Length for Heterogeneous Terrain

A new method is proposed for the effective roughness length (ERL) in heterogeneous terrain based on the principle of equalisation of momentum or heat fluxes calculated by the drag coefficient parameterization scheme used in the ECMWF numerical model. Compared with the area-weighted logarithmically averaged ERL (drag coefficient), the newly calculated ERL (drag coefficient) is about 40% (16%) larger with a roughness step of 2.3. These differences reach their maximum values when the ratio of smooth to rough surface is 60% to 40%. Since the determination by this method is not sensitive to the atmospheric stratification, it is suitable for use in climate models.

Mapping of QTLs Controlling Panicle Length and Effective Panicle Number of Rice

Panicle length and effective panicle number of rice are closely related to yield. In this experiment, indica V20B as female parent was crossed with javanica CPSLO17 as male parent, recombinant inbred line （RIL） populations were obtained by single seed descent method, and with the RIL populations as mapping populations, QTL mapping and analysis were performed to the two panicle traits, panicle length and effective panicle. A high-density genetic map was constructed with SLAF labels, interval mapping was performed by software Map QTL5 under the threshold of 3.9, and 7 QTLs were detected on 3 chromosomes in total. Among the 7 QTLs, 5 QTLs controlling panicle length （qPLI-1, qPL1-2, qPL6-1, qPI_6-2 and qPL6-3） were located on chromosomes 1 and 6, respectively, and showed the contribution rates of 6.41%, 22.22%, 6.15%, 12.24% and 13.01%, respectively, their effect-increasing loci were mainly from CPSLO17, and qPL1-1 is a new QTL; and 2 QTLs controlling effective panicle number （qPN1 and qPN4） were located on chromosomes 1 and 4, respectively, and exhibited the contribution rates of 13.15% and 8.18%, respectively, and the effect-increasing loci were from parent V2OB. The marking of these loci lays a foundation for further cloning of genes controlling panicle length and effective panicle number and molecular marker-assisted selection.

Maximum Momentum,Minimal Length and Quantum Gravity Effects of Compact Star Cores

Based on the generalized uncertainty principle with maximum momentum arid minimal length, we discuss the equation of state of ideal ultra-relativistic Fermi gases at zero temperature. Maximum momentum avoids the problem that the Fermi degenerate pressure blows up since the increase of the Fermi energy is not limited. Applying this equation of state to the Tolman-Oppenheimer Volkoff （TOV） equation, the quantum gravitational effects on the cores of compact stars are discussed. In the center of compact stars, we obtain the singularity-free solution of the metric component, gtt ～-（1 ＋ 0.2185×r^2）. By numerically solving the TOV equation, we find that quantum gravity plays an important role in the region r～10^4α0（△x）min. Current observed masses of neutron stars indicate that the dimensionless parameter α0 cannot exceed 10^19.

Ion source effect on the bond length of ^4HeH^＋

The bond length of ^4HeH^＋ resulting from collision-induced destruction is measured at 1.4420 MeV using the Coulomb Explosion Technique. The measured bond length of ^4HeH^＋ is 0.094±0.003nm. The bond length of ^4HeH^＋ obtained with our radio frequency （RF） ion source is larger than that obtained with a duoplasmatron ion source at Argonne National Laboratory （ANL）, but the bond lengths of H^＋2 and H^＋3obtained separately by ANL and by us with the two different ion sources are consistent with each other, which implies that there exists an ion source effect on the bond length of ^4HeH^＋. The main reason why the 4^4HeH^＋ bond lengths obtained by the two different ion sources are different is also discussed.

Nonlinear mixed-effects height to crown base and crown length dynamic models using the branch mortality technique for a Korean larch( Larix olgensis ) plantations in northeast China

Korean larch(Larix olgensis)is one of the main tree species for aff orestation and timber production in northeast China.However,its timber quality and growth ability are largely infl uenced by crown size,structure and shape.The majority of crown models are static models based on tree size and stand characteristics from temporary sample plots,but crown dynamic models has seldom been constructed.Therefore,this study aimed to develop height to crown base(HCB)and crown length(CL)dynamic models using the branch mortality technique for a Korean larch plantation.The nonlinear mixed-eff ects model with random eff ects,variance functions and correlation structures,was used to build HCB and CL dynamic models.The data were obtained from 95 sample trees of 19 plots in Meng JiaGang forest farm in Northeast China.The results showed that HCB progressively increases as tree age,tree height growth(HT growth)and diameter at breast height growth(DBH growth).The CL was increased with tree age in 20 years ago,and subsequently stabilized.HT growth,DBH growth stand basal area(BAS)and crown competition factor(CCF)signifi cantly infl uenced HCB and CL.The HCB was positively correlated with BAS,HT growth and DBH growth,but negatively correlated with CCF.The CL was positively correlated with BAS and CCF,but negatively correlated with DBH growth.Model fi tting and validation confi rmed that the mixed-eff ects model considering the stand and tree level random eff ects was accurate and reliable for predicting the HCB and CL dynamics.However,the models involving adding variance functions and time series correlation structure could not completely remove heterogeneity and autocorrelation,and the fi tting precision of the models was reduced.Therefore,from the point of view of application,we should take care to avoid setting up over-complex models.The HCB and CL dynamic models in our study may also be incorporated into stand growth and yield model systems in China.

Effective Channel Length Degradation under Hot-Carrier Stressing

This article describes the effective channel length degradation under hot carrier stressing. The extraction is based on the IDs-Vcs characteristics by maximum transconductance （maximum slope of IDs ＆ VGS） in the linear region. The transconductance characteristics are determine for the several devices of difference drawn channel length. The effective channel length of submicron LDD （Lightly Doped Drain） NMOSFETs （Metal Oxide Semiconductor Field Effect Transistor） under hot carrier stressing was measured at the stress time varying from zero to 10,000 seconds. It is shown that the effective channel length was increased with time. This is caused by charges trapping in the oxide during stress. The increased of effective channel length （△Leff） is seem to be increased sharply as the gate channel length is decrease.

Surface effects on the persistence length of nanowires and nanotubes

Surface effects on the persistence length of quasi-one-dimensional nanomaterials are investigated by using the theory of surface elasticity and the core-shell model of nanobeams. A simple and unified expression is provided to determine the persistence length of nanowires and nanotubes with any regular polygonal cross-sections. It is demonstrated that surface effects have a distinct in- fluence on the persistence length when the characteristic sizes of materials shrink to nanometers. This work is helpful not only for understanding the size-dependent behavior of nanomaterials but also for the design of devices based on nanotubes or nanowires.

Open Partial Nephrectomy: One Night Length of Stay Is Safe and Cost Effective

Objective: To review our open partial nephrectomy (OPN) experience and compare to known robotic partial nephrectomy (RPN) data to determine whether length of stay (LOS) and morbidity are significant drivers in the surgical approach employed for partial nephrectomy. Methods: We reviewed our OPN experience during the last 3 years examining age, tumor size, LOS, pathology, blood loss, complications, recurences, and deaths. Results: Seventy-five patients underwent OPN during this period. Mean age was 59 years, tumor size 2.8 cm, percent malignant 75%, estimated blood loss 350 cc. With a median follow-up of 18 months, there was one urinoma managed by drain-age, one pseudo aneurysm that required embolization and one pulmonary embolism that required anticoagulation. There were no readmissions, no tumor recurences, and no deaths. Our major complication rate was 4% as compared to other trials that re-ported major complication rates between 1% - 9% for RPN and between 3% - 24% for OPN. In the first half of the experience (n = 37), median LOS was 57 hours. Using a pathway encouraging early ambulation and smaller incisions in the second half of the experience (n = 38), median LOS was 35 hours. This is much shorter than reported RPN LOS of 62 - 67 hours and OPN LOS of 108 - 142 hours. Conclusion: OPN can be performed safely and effectively with one night hospital stay. This provides a more cost-effective approach to partial nephrectomy with similar or better complication rates and calls into question the main value drivers of RPN.

The Effective Buckling Length on Numerical Study of Pipe-Sectioned Pier-Pile Integral Steel Structure

Pier-Pile integral structures provide construction works with many environmental and landscape advantages. For example, the space required to construct these structures is smaller than that of other bridges due to the footing being removed, meaning that it is not necessity to greatly change the surroundings of these bridges. While there are environmental and landscape advantages, there are also a few demerits for the overall land-scape designs, including demerits in the design of this proposed structure which consists of relatively slender parts. This proposed structure has already been constructed in areas where possibility of a severe earthquake is low. However, some problems that have yet to be examined are related to the use of this proposed structure in areas where earthquakes are frequent. Lacking detailed studies of its behavior during severe earthquakes, it is currently difficult to construct these structures in Japan. Consequently, it is necessary to investigate in detail limited performance about compression and bending moment, and earthquake- resistant performance of these structures in order to resolve these problems. In this paper, It was clarified the relationship between the rigidity of the ground and the effective buckling length by buckling analysis and elasto- plastic finite deformation analysis. Moreover, it was proposed a simplified formula using a proposed characteristic value β and several factors for analysis accuracy. A simplified formula would support to determine the effective buckling length to design the pier using the load-bearing capacity curve based on the slenderness ratio parameter.

Effect of day length and temperature on the pollen fertility in photo(thermo)-sensitive genic male-sterile rice

The effect of day length and temperature on the pollen fertility of five photoperiod-sensitive genic male-sterile japonica rice lines (PGMSR) and three temperature-sensitive genic malesterile indica rice lines (TGMSR) were investigated in phytotron. The light source used for illumination was xenon lamp, and the light intensity which plant accepted on the leaf surface was 300—350μmol photons ms. The results indicated that pollens of PGMSR 7001S and E47S aborted completely whereas a little part of 31116S pollens appeared normal under long day photoperiod (LD,25℃,15h) (Table 1). High temperature (HT, 30℃, 12h) and lower temperature (LT,

不同冲击气压下煤样动态剪切强度的长径比效应

采用Φ50mm分离式霍普金森压杆(SHPB)试验系统,开展了不同冲击气压下直径75mm,长径比分别为0.20,0.27,0.33,0.40和0.47的5组煤样的动态剪切试验,划分了煤动态剪应力时程曲线的阶段,探讨了冲击气压对煤样动态剪切强度的影响,分析了煤样动态剪切强度和加载率的长径比效应,并建立了长径比效应理论模型。研究结果表明:①煤样动态剪应力时程曲线可分为应力初始上升、应力线性增长、应力缓慢上升和应力下降4个阶段;②煤样动态剪切强度与冲击气压呈正线性相关,但不同长径比下增加幅度存在差异,具体表现为:相同冲击气压增量下,煤样长径比越小,动态剪切强度的增加幅度越大;③煤样动态剪切强度和加载率均与长径比有关,在0.25,0.35 MPa较低冲击气压与0.45,0.55 MPa较高冲击气压下分别呈现出正、负长径比效应,并通过方差分析确定了长径比对其影响最小的冲击气压为0.376MPa;④建立了不同冲击气压下煤样动态剪切强度长径比效应理论模型,通过加载率效应推导出加载率长径比效应理论模型,并验证了模型的合理性和准确性。

平头车变长头车以保护行人头部损伤的方法及效能研究

为提升平头车保护人体头部损伤的能力和法规上的接受水平,通过推导车头伸出长度公式而给出一种使平头车变长头车的方法,随后通过理论和仿真分析研究所提方法的损伤防护效果及摩擦因数、车速和行人身高等因素对防护效果的影响规律。结果显示:所提方法能极显著降低行人头部损伤,且在低速、低摩擦、矮行人身高下防护效果更佳。分析发现伸出可变车头长度优于固定车头长度,而在获得更高精度行人损伤风险曲线后可进一步优化所提方法。该研究将为M类、N类等大型平头车辆保护行人提供新思路,为它们利用长头车智能安全技术以更好地保护行人提供支持。

Effect of Overlap Stress as Well as Tie Beam Length and Width on Settlement of Isolated Footings Using Finite Element

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.

平均住院日影响因素及管理改进研究

目的基于精益管理理念,借助循证医学工具分析某三级甲等医院的平均住院日现状及影响因素,通过实施改进和效果评价,旨在形成可推广复制的医院高效运营策略。方法以某三级甲等医院为研究对象,使用Cite Space进行文献可视化分析、结合医院现状找出影响因素;应用Spearman进行单因素分析和多因素Logistic回归分析,明确平均住院日的关键影响因素;提出实施针对性改进措施并实施效果评价。结果影响平均住院日的主要因素为平均待术日、转诊率和临床路径管理率。改进后平均住院日由6.59天下降至5.94天。结论借助医院信息技术和医疗资源合理配置,优化收治流程、提升医技效率;落实双向转诊政策,引导患者合理流动,共建区域医疗合作圈;优化路径管理和考核,规范诊疗行为等措施,可有效缩短医院平均住院日,提高医院运行效率。

Compressed H3S: Fits to the Empirical Hc2(T) Data and a Discussion of the Meissner Effect

Based on μ-, T- and H-dependent pairing and number equations and the premise that μ(T) is predominantly the cause of the variation of the upper critical field Hc2(T), where μ, T and H denote the chemical potential, temperature and the applied field, respectively, we provide in this paper fits to the empirical Hc2(T) data of H3S reported by Mozaffari, et al. (2019) and deal with the issue of whether or not H3S exhibits the Meissner effect. Employing a variant of the template given by Dogan and Cohen (2021), we examine in detail the results of Hirsch and Marsiglio (2022) who have claimed that H3S does not exhibit the Meissner effect and Minkov, et al. (2023) who have claimed that it does. We are thus led to suggest that monitoring the chemical potential (equivalently, the number density of Cooper pairs Ns at T = Tc) should shed new light on the issue being addressed.

基于TOPSIS方法的油气井射孔参数优化决策模型研究

为了提升油气井的产能和经济效益,对射孔参数进行了深入研究,通过分析射孔过程的物理机理及其影响因素,提出了一套综合考虑套管安全、射孔孔眼参数和射孔通道表皮系数的多属性评价指标体系,全面评估了射孔参数对油气井安全和效益的影响;在此基础上,研究构建了一种基于TOPSIS的多属性决策模型,用于优化射孔参数选择。该模型通过计算各指标的权重和排序,可以有效筛选出最佳射孔参数组合。研究结果表明:①所提出的TOPSIS模型能够有效地优化射孔参数,提高射孔效率;②该模型确保了油气井的安全运行,降低了操作风险;③应用该模型显著提升了油气井的经济效益。这些成果验证了模型的有效性和优越性,与传统的经验法和试井法相比,提供了更为科学的决策支持。结论认为,该研究成果为油气井射孔参数的优化提供了一种新的科学决策方法,有助于指导实际的射孔操作,优化完井工艺,提高生产性能,为油气井经济效益的提升提供了理论支持和实践指导。

考虑杆件尺寸相关性的受电弓运动可靠性分析

为分析杆件尺寸参数的关联特性对机构运动可靠性的影响规律,提出一种基于Cholesky法则的机构运动可靠性分析方法。首先,根据机构运动学原理构建机构运动学方程;其次,结合有效长度理论,建立考虑运动副间隙的杆件有效长度模型,在此基础上,引入Archard磨损模型量化运动周期对杆件有效长度的影响,通过蒙特卡罗法获取不同运动周期下的杆件尺寸样本数据并计算样本相关系数,进而利用Cholesky法则完成不同运动周期下的杆件样本数据重构,并结合可靠性理论对机构运动可靠性进行评估;最后,以受电弓机构为例,验证了所提方法的有效性。计算分析结果表明:杆件样本数据关联性由于运动副间隙的存在而增强,并随运动副间隙的增加愈加显著;与传统分析方法相比,基于Cholesky法则的机构运动可靠性指标存在一定程度降幅,能够为实际机构可靠性评估提供更为安全的参考价值。