Dynamic Characteristics of Woodframe Buildings

The dynamic properties of wood shearwall buildings were evaluated, such as modal frequencies, damping and mode shapes of the structures. Through analysis of recorded earthquake response and by forced vibration testing, a database of periods and damping ratios of woodframe buildings was developed. Modal identification was performed on strong-motion records obtained from five buildings, and forced vibration tests were performed on a two-story house and a three-story apartment building, among others. A regression analysis is performed on the database to obtain a period formula specific for woodframe buildings. It should be noted that all test results, including the seismic data, are at small drift ratios (less than 0.1%), and the periods would be significantly longer for stronger shaking of these structures. Despite these low amplitudes, the equivalent viscous dampings for the fundamental modes were usually more than 10% of critical during earthquake shaking

Dense Molecular Filaments Feeding a Starburst: ALMA Maps of CO(3-2) in Henize 2-10

We present ALMA CO(3-2) observations at 0.3 arcsec resolution of He2-10, a starburst dwarf galaxy and possible high-z galaxy analogue. The warm dense gas traced by CO(3--2) is found in clumpy filaments that are kinematically and spatially distinct. The filaments have no preferred orientation or direction; this may indicate that the galaxy is not evolving into a disk galaxy. Filaments appear to be feeding the active starburst; the velocity field in one filament suggests acceleration onto an embedded star cluster. The relative strengths of CO(3-2) and radio continuum vary strongly on decaparsec scales in the starburst. There is no CO(3--2) clump coincident with the non-thermal radio source that has been suggested to be an AGN, nor unusual kinematics. The kinematics of the molecular gas show significant activity apparently unrelated to the current starburst. The longest filament, east of the starburst, has a pronounced shear of FWHM $\sim40$~\kms\ across its $\sim$50~pc width over its entire $\approx 0.5$ kpc length. The cause of the shear is not clear. This filament is close in projection to a `dynamically distinct' CO feature previously seen in CO(1--0). The most complex region and the most highly disturbed gas velocities are in a region 200~pc south of the starburst. The CO(3--2) emission there reveals a molecular outflow, of linewidth FWZI $\sim$ 120-140 \kms, requiring an energy $\gtrsim 10^{53} \rm~ erg/s$. There is at present {\it no} candidate for the driving source of this outflow.Comment: This was revised 31 October to correct some typos and to replace Figure

Damage Detection of Structural Systems with Noisy Incomplete Input and Response Measurements

A probabilistic approach for damage detection is presented using noisy incomplete input and response measurements that is an extension of a Bayesian system identification approach developed by the authors. This situation may be encountered, for example, during low-level ambient vibrations when a structure is instrumented with accelerometers that measure the input ground motion and structural response at a few locations but the wind excitation is not measured. A substructuring approach is used for the parameterization of the mass and stiffness distributions. Damage is defined to be a reduction of the substructure stiffness parameters compared with those of the undamaged structure. By using the proposed probabilistic methodology, the probability of various damage levels in each substructure can be calculated based on the available data. A four-story benchmark building subjected to wind and ground shaking is considered in order to demonstrate the proposed approach

Can Long-Range Nuclear Properties Be Influenced By Short Range Interactions? A chiral dynamics estimate

Recent experiments and many-body calculations indicate that approximately 20\% of the nucleons in medium and heavy nuclei ($A\geq12$) are part of short-range correlated (SRC) primarily neutron-proton ($np$) pairs. We find that using chiral dynamics to account for the formation of $np$ pairs due to the effects of iterated and irreducible two-pion exchange leads to values consistent with the 20\% level. We further apply chiral dynamics to study how these correlations influence the calculations of nuclear charge radii, that traditionally truncate their effect, to find that they are capable of introducing non-negligible effects.Comment: 6 pages, 0 figures. This version includes many improvement

Statistics of football dynamics

We investigate the dynamics of football matches. Our goal is to characterize statistically the temporal sequence of ball movements in this collective sport game, searching for traits of complex behavior. Data were collected over a variety of matches in South American, European and World championships throughout 2005 and 2006. We show that the statistics of ball touches presents power-law tails and can be described by $q$-gamma distributions. To explain such behavior we propose a model that provides information on the characteristics of football dynamics. Furthermore, we discuss the statistics of duration of out-of-play intervals, not directly related to the previous scenario.Comment: 7 page

Phase II of the ASCE Benchmark Study on SHM

The task group on structural health monitoring of the Dynamic Committee of ASCE was formed in 1999 at the 12 th Engineering Mechanics Conference. The task group has designed a number of analytical studies on a benchmark structure and there are plans to follow these with an experimental program. The first phase of the analytical studies was completed in 2001. The second phase, initiated in the summer of 2001, was formulated in the light of the experience gained on phase I and focuses on increasing realism in the simulation of the discrepancies between the actual structure and the mathematical model used in the analysis. This paper describes the rational that lead the SHM task group to the definition of phase II and presents the details of the cases that are being considered

Distributed-Pair Programming can work well and is not just Distributed Pair-Programming

Background: Distributed Pair Programming can be performed via screensharing or via a distributed IDE. The latter offers the freedom of concurrent editing (which may be helpful or damaging) and has even more awareness deficits than screen sharing. Objective: Characterize how competent distributed pair programmers may handle this additional freedom and these additional awareness deficits and characterize the impacts on the pair programming process. Method: A revelatory case study, based on direct observation of a single, highly competent distributed pair of industrial software developers during a 3-day collaboration. We use recordings of these sessions and conceptualize the phenomena seen. Results: 1. Skilled pairs may bridge the awareness deficits without visible obstruction of the overall process. 2. Skilled pairs may use the additional editing freedom in a useful limited fashion, resulting in potentially better fluency of the process than local pair programming. Conclusion: When applied skillfully in an appropriate context, distributed-pair programming can (not will!) work at least as well as local pair programming

Status of Nucleon Resonances with Masses M<MN+MπM<M_N+M_{\pi}

We discuss different interpretations of peaks observed a few years ago by Tatischeff et al. in missing mass spectra of the reaction $pp->pi^+pX$, which were declared as new exited nucleon states with small masses. A study of the possible production of such states in the process $\gamma p->pi^+N^*->pi^+ +\gamma\gamma n$ by analyzing the invariant mass spectrum of $\gamma\gamma n$ is proposed. It is shown that the data, obtained recently at MAMI-B, can allow to analyze this process and to get information about an existence of exited nucleon states with small masses.Comment: 4 pages, 2 figures, LaTeX with ws-p8-50x6-00.cls. Talk presented at the NSTAR2001 Workshop, Mainz, Germany, March 7-10, 200

A method to estimate trends in distributions of 1 min rain rates from numerical weather prediction data

It is known that the rain rate exceeded 0.01% of the time in the UK has experienced an increasing trend over the last 20 years. It is very likely that rain fade and outage experience a similar trend. This paper presents a globally applicable method to estimate these trends, based on the widely accepted Salonen-Poiares Baptista model. The input data are parameters easily extracted from numerical weather prediction reanalysis data. The method is verified using rain gauge data from the UK, and the predicted trend slopes of 0.01% exceeded rain rate are presented on a global grid