NDM-541: THE HEAT LOADS OF A TUNED MASS DAMPER

Modern tall buildings are often susceptible to excessive wind-induced motions. Tuned mass dampers (TMDs) are used to improve occupant comfort by reducing structural accelerations during common winds, and also to reduce building drift during stronger winds. A TMD is an auxiliary mass that is connected near the top of the structure through elements that produce restoring and damping forces. If the TMD is designed to have the appropriate natural frequency and damping ratio, vibrational energy from the structure is transferred to the TMD where it is dissipated through the TMD damping. This additional source of energy dissipation increases the effective damping of the building, reducing its dynamic motion. The energy dissipating elements of the TMD, whether linear or nonlinear, will convert some of the TMD’s kinetic energy into heat. It is critical that the heat generated by the TMD motion is accurately predicted, and the damping device is demonstrated to be capable of ejecting this heat. If the device cannot eject the heat it generates during operation, the device may overheat, altering its damping properties or potentially leading to device failure. This paper studies the rate of heat generation (power) of a TMD with two common forms of damping. Simple techniques are employed to calculate the mean TMD power. Nonlinear simulations are used to evaluate this simple model, and predict the peak TMD power that is expected over a short period of time. For a given structural acceleration reduction, the TMD power is independent of the form of damping

Dynamics of Perfectly Wetting Drops under Gravity

We study the dynamics of small droplets of polydimethylsiloxane (PDMS) silicone oil on a vertical, perfectly-wetting, silicon wafer. Interference videomicroscopy allows us to capture the dynamics of these droplets. We use droplets with a volumes typically ranging from 100 to 500 nanolitres (viscosities from 10 to 1000 centistokes) to understand long time derivations from classical solutions. Past researchers used one dimensional theory to understand the typical $t^{1/3}$ scaling for the position of the tip of the droplet in time $t$. We observe this regime in experiment for intermediate times and discover a two-dimensional, similarity solution of the shape of the droplet. However, at long times our droplets start to move more slowly down the plane than the $t^{1/3}$ scaling suggests and we observe deviations in droplet shape from the similarity solution. We match experimental data with simulations to show these deviations are consistent with retarded van der Waals forcing which should become significant at the small heights observed

STR-926: FOOTFALL-INDUCED VIBRATION: PREDICTION AND CONTROL STRATEGIES

Footfalls can produce vibrations that are irritating to occupants, or disruptive to vibration-sensitive spaces in hospitals and research laboratories. This paper describes, using case studies, techniques that can be used to predict vibrations, and mitigation strategies to control them. Firstly, pedestrian loading on footbridges is described. Stochastic simulations are conducted in which a number of pedestrians with random weights, walking speeds, and walking paths cross a bridge with random spacing. The resulting vibration response of the bridge is determined to estimate the peak acceleration of the bridge. For the case considered, tuned mass dampers (TMDs) were subsequently installed on the bridge to increase the effective damping of two modes. Next, crowd loading on stadia and ballroom structures is considered. For these structures, the crowd-structure interaction must be considered since the mass of the crowd is a significant fraction of the mass of the structure, which alters the dynamic response of the system. In the case presented, TMDs are considered to reduce the vibrations associated with crowd excitation. Lastly, the vibrations associated with a pedestrian walking in a corridor adjacent to a vibration-sensitive room in a hospital or research facility are described. Maintaining low vibrations in these hospitals and laboratories is critical as the operation of equipment may be adversely affected by vibrations that are well below the threshold of human perception. Typical mitigation strategies for these vibrations include positioning sensitive equipment near columns or increasing the stiffness or mass of the floor

Complete Genome Sequence of Mesorhizobium ciceri Strain CC1192, an Efficient Nitrogen-Fixing Microsymbiont of Cicer arietinum.

We report the complete genome sequence of Mesorhizobium ciceri strain CC1192, an efficient nitrogen-fixing microsymbiont of Cicer arietinum (chickpea). The genome consists of 6.94 Mb distributed between a single chromosome (6.29 Mb) and a plasmid (0.65 Mb)

Complete Genome Sequence of Mesorhizobium ciceri bv. biserrulae Strain WSM1284, an Efficient Nitrogen-Fixing Microsymbiont of the Pasture Legume Biserrula pelecinus.

We report the complete genome sequence of Mesorhizobium ciceri bv. biserrulae strain WSM1284, a nitrogen-fixing microsymbiont of the pasture legume Biserrula pelecinus The genome consists of 6.88 Mb distributed between a single chromosome (6.33 Mb) and a single plasmid (0.55 Mb)

Creating a Language Archive of Insular South East Asia and West New Guinea

The geographical region of Insular South East Asia and New Guinea is well-known as an area of mega-biodiversity. Less well-known is the extreme linguistic diversity in this area: over a quarter of the world’s 6,000 languages are spoken here. As small minority languages, most of them will cease to be spoken in the coming few generations. The project described here ensures the preservation of unique records of languages and the cultures encapsulated by them in the region. The language resources were gathered by twenty linguists at, or in collaboration with, Dutch universities over the last 40 years, and were compiled and archived in collaboration with The Language Archive (TLA) at the Max Planck Institute in Nijmegen. The resulting archive constitutes a collection ofmultimediamaterials and written documents from 48 languages in Insular South East Asia and West New Guinea. At TLA, the data was archived according to state-of-the-art standards (TLA holds the Data Seal of Approval): the component metadata infrastructure CMDI was used; all metadata categories as well as relevant units of annotation were linked to the ISO data category registry ISOcat. This guaranteed proper integration of the language resources into the CLARIN framework. Through the archive, future speaker communities and researchers will be able to extensively search thematerials for answers to their own questions, even if they do not themselves know the language, and even if the language dies

Severity of depression and hypothalamic-pituitary-adrenal axis dysregulation: identification of contributing factors

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65507/1/j.1600-0447.1990.tb05465.x.pd

A psychoendocrine study of premenstrual tension syndrome : A model for endogenous depression?

We studied 42 women with severe Premenstrual Tension Syndrome (PMTS) and compared their clinical features and adrenocortical function with those seen in major depressive disorders. Self-report scales demonstrated that PMTS was very distressing, but the disturbance did not meet the RDC for Major Depressive Disorder -- endogenous subtype. Twenty-four hour urinary free cortisol estimation did not indicate cortisol hypersecretion and abnormal Dexamethasone Suppression Test results occured much less frequently than is usual in endogenous depression. Adrenocortical function did not differ significantly between follicular and premenstrual phases. PMTS does not appear to be a psychoendocrine model for endogenous depression.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24853/1/0000280.pd

Serial dexamethasone suppression tests in simultaneous panic and depressive disorders

Recent work suggests that the simultaneous occurrence of major depressive disorder (MDD) and panic disorder (PD) may be of relevance for clinical findings, therapeutic outcome, and prognosis. It is of interest to know whether or not this relevance extends to biological findings. We addressed this question through comparison of serial Dexamethasone Suppression Test (DST) results in patients who had either MDD alone or simultaneous MDD and PD. We were unable to describe differences between the groups.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26790/1/0000346.pd