scholarly journals A new method for the measurement of the natural periods of buildings

1964 ◽  
Vol 54 (1) ◽  
pp. 233-241
Author(s):  
D. E. Hudson ◽  
W. O. Keightley ◽  
N. N. Nielsen
Keyword(s):  
Fundamental Mode ◽  
New Method ◽  
Inertia Force ◽  
Large Structure ◽  
Structural Vibrations ◽  
Natural Period ◽  
The Past ◽  
Modes Of Vibration ◽  
Set Up

abstract It is shown that the inertia force obtained by a man moving his body back and forth in synchronism with the natural period of vibration of a large structure is sufficient to build up a measurable amplitude of motion. By recording such structural vibrations versus time, the natural period and damping of several of the lower modes of vibration can be determined. The amplitudes of motion set up in this way are for many structures significantly larger than can be obtained from wind excitation, which has been used in the past for the measurement of the period of the fundamental mode.

Children’s Lives and Deaths in Merovingian Gaul

2020 ◽  
pp. 185-213
Author(s):  
Émilie Perez
Keyword(s):  
Social Identity ◽  
Age Groups ◽  
New Method ◽  
Recent Analysis ◽  
Age And Gender ◽  
The Past ◽  
And Gender ◽  
Grave Goods

The role of children in Merovingian society has long been downplayed, and the study of their graves and bones has long been neglected. However, during the past fifteen years, archaeologists have shown growing interest in the place of children in Merovingian society. Nonetheless, this research has not been without challenges linked to the nature of the biological and material remains. Recent analysis of 315 children’s graves from four Merovingian cemeteries in northern Gaul (sixth to seventh centuries) allows us to understand the modalities of burial ritual for children. A new method for classifying children into social age groups shows that the type, quality, quantity, and diversity of grave goods were directly correlated with the age of the deceased. They increased from the age of eight and particularly around the time of puberty. This study discusses the role of age and gender in the construction and expression of social identity during childhood in the Merovingian period.

scholarly journals On Kaufmann's theory of the impact of the pianoforte hammer

1920 ◽  
Vol 97 (682) ◽  
pp. 99-110 ◽  
Keyword(s):  
Initial Conditions ◽  
Practical Importance ◽  
Prima Facie ◽  
Point Of View ◽  
Infinite Length ◽  
Modes Of Vibration ◽  
Rigorous Treatment ◽  
The Subject ◽  
Set Up ◽  
The Impact

The theory of the vibrations of the pianoforte string put forward by Kaufmann in a well-known paper has figured prominently in recent discussions on the acoustics of this instrument. It proceeds on lines radically different from those adopted by Helmholtz in his classical treatment of the subject. While recognising that the elasticity of the pianoforte hammer is not a negligible factor, Kaufmann set out to simplify the mathematical analysis by ignoring its effect altogether, and treating the hammer as a particle possessing only inertia without spring. The motion of the string following the impact of the hammer is found from the initial conditions and from the functional solutions of the equation of wave-propagation on the string. On this basis he gave a rigorous treatment of two cases: (1) a particle impinging on a stretched string of infinite length, and (2) a particle impinging on the centre of a finite string, neither of which cases is of much interest from an acoustical point of view. The case of practical importance treated by him is that in which a particle impinges on the string near one end. For this case, he gave only an approximate theory from which the duration of contact, the motion of the point struck, and the form of the vibration-curves for various points of the string could be found. There can be no doubt of the importance of Kaufmann’s work, and it naturally becomes necessary to extend and revise his theory in various directions. In several respects, the theory awaits fuller development, especially as regards the harmonic analysis of the modes of vibration set up by impact, and the detailed discussion of the influence of the elasticity of the hammer and of varying velocities of impact. Apart from these points, the question arises whether the approximate method used by Kaufmann is sufficiently accurate for practical purposes, and whether it may be regarded as applicable when, as in the pianoforte, the point struck is distant one-eighth or one-ninth of the length of the string from one end. Kaufmann’s treatment is practically based on the assumption that the part of the string between the end and the point struck remains straight as long as the hammer and string remain in contact. Primâ facie , it is clear that this assumption would introduce error when the part of the string under reference is an appreciable fraction of the whole. For the effect of the impact would obviously be to excite the vibrations of this portion of the string, which continue so long as the hammer is in contact, and would also influence the mode of vibration of the string as a whole when the hammer loses contact. A mathematical theory which is not subject to this error, and which is applicable for any position of the striking point, thus seems called for.

scholarly journals Personal Carbon Trading—Lost in the Policy Primeval Soup?

2021 ◽  
Vol 13 (8) ◽  
pp. 4592
Author(s):  
Fabio Bothner
Keyword(s):  
Ghg Emissions ◽  
Emission Trading ◽  
Political Agenda ◽  
Carbon Trading ◽  
Multiple Streams ◽  
Policy Proposal ◽  
The Past ◽  
Multiple Streams Approach ◽  
Carbon Taxation ◽  
Set Up

The number of emission trading and carbon taxation schemes implemented has grown rapidly over the past decade. Together, they cover approximately 16% of global greenhouse gas (GHG) emissions. Although more than two-thirds of global GHG emissions are related to household consumption, approaches that directly target households, such as personal carbon trading (PCT), do not play a role in the fight against climate change. This is especially puzzling as measures taken so far are not sufficient to reach the 2 °C target. One clue to solving this puzzle comes from political science in the form of the multiple streams approach, which defines criteria that a policy proposal must meet to become part of the political agenda. Based on these criteria, this article conducts a systematic review on PCT to clarify why PCT does not play a role in the reduction of GHG emissions. The results show that there are three main problems with the PCT proposal. First, scholars often criticize the set-up costs as well as the running costs of such a system. Second, there is no clear consensus within the research community on public acceptance of PCT. Third, it is still unclear whether politicians are receptive to PCT or not.

scholarly journals Maudsley International: improving mental health and well-being around the world

2018 ◽  
Vol 15 (3) ◽  
pp. 49-51 ◽  
Author(s):  
Nick Bouras ◽  
Silvia Davey ◽  
Tracey Power ◽  
Jonathan Rolfe ◽  
Tom Craig ◽  
...  
Keyword(s):  
Mental Health ◽  
Social Care ◽  
Well Being ◽  
Building Capacity ◽  
The Past ◽  
Health And Social Care ◽  
The World ◽  
Set Up ◽  
Health And Well Being ◽  
And Training

Maudsley International was set up to help improve people's mental health and well-being around the world. A variety of programmes have been developed by Maudsley International over the past 10 years, for planning and implementing services; building capacity; and training and evaluation to support organisations and individuals, professionals and managers to train and develop health and social care provisions. Maudsley International's model is based on collaboration, sharing expertise and cultural understanding with international partners.

Military Power and Constitutional Development in China

1921 ◽  
Vol 15 (2) ◽  
pp. 233-252
Author(s):  
Harold M. Vinacké
Keyword(s):  
Political Institutions ◽  
Military Government ◽  
Representative Government ◽  
Constitutional Development ◽  
Revolutionary Movement ◽  
Chinese Revolution ◽  
Parliamentary Government ◽  
The Past ◽  
Popular Government ◽  
Set Up

It is now nine years since the outbreak of the Chinese revolution. It is fifteen years since the Manchus attempted to maintain their control by introducing representative institutions into China. The development toward constitutional and representative government under the Manchus was checked in 1911 by the revolutionary movement. When the Chinese Republic was established as the successor to the alien Manchu Empire it was felt that the problem of modernizing China bade fair to be solved, and that in an orderly way her political institutions would be brought into harmony with western standards. Unfortunately that orderly progress has not come. Parliamentary government under the Nanking (provisional) Constitution was replaced by the dictatorship of Yuan Shih-kai under the arrangements of the so-called constitutional compact, which in turn was followed by the attempt to reëstablish the monarchy. The failure of the monarchy movement brought back parliamentary government, but before a permanent constitution could be adopted Parliament was again dissolved, and a government controlled by a military clique set up in its place. Since this military government was unacceptable to the southern provinces, the country became divided. So far it has not been possible for the country to reconcile its differences. Instead of an ordered constitutional progress, has come apparent failure in the effort to establish representative government. The name of a republic has been maintained, it is true, and the forms of constitutional government have been retained, but a permanent national government has not been set up, nor has popular government replaced the paternal despotism of the past.

Development and Verification of Modeling Practice for CFD Decay Calculations to Obtain Roll Damping of FPSO

2021 ◽  
Author(s):  
Arjen Koop ◽  
Pierre Crepier ◽  
Sebastien Loubeyre ◽  
Corentin Dobral ◽  
Kai Yu ◽  
...  
Keyword(s):  
Model Test ◽  
Test Results ◽  
Cfd Modelling ◽  
Roll Damping ◽  
Natural Period ◽  
Computational Mesh ◽  
Safety Studies ◽  
Offshore Industry ◽  
Decay Tests ◽  
Set Up

Abstract Estimates for roll damping are important input parameters for simulation studies on vessels operating at sea, e.g. FPSO mooring in waves, wind and current, workability and operability investigations, Dynamic Position studies, ship-to-ship operations and safety studies of vessels. To accurately predict the motions of vessels this quantity should be determined with confidence in the values. Traditionally, model experiments in water basins using so-called decay tests are carried out to determine the roll damping. With recent advancements in CFD modelling, the offshore industry has started using CFD as an alternative tool to compute the roll damping of FPSO’s. In order to help adopt CFD as a widely accepted tool, there is a need to develop confidence in CFD predictions. Therefore, a practical CFD modelling practice is developed within the Reproducible CFD JIP for roll decay CFD simulations. The Modelling Practice describes the geometry modelling, computational mesh, model set-up and post-processing for these type of CFD calculations. This modelling practice is verified and validated by three independent verifiers against available model test data. This paper provides an overview of the developed modelling practice and the calculated CFD results from the verifiers. The CFD modelling practice is benchmarked against available model test results for a tanker-shaped FPSO. By following this modelling practice, the CFD predictions for the equivalent linear damping coefficient and natural period of the roll motions are within 10% for all verifiers and within 10% from the model test results. Therefore, we conclude that when following the developed modelling practice for roll decay simulations, reliable, accurate and reproducible results can be obtained for the roll damping of tanker-shaped FPSOs.

Vibration of Rectangular Plates by the Ritz Method

1950 ◽  
Vol 17 (4) ◽  
pp. 448-453 ◽  
Author(s):  
Dana Young
Keyword(s):  
Ritz Method ◽  
Normal Modes ◽  
Approximate Solutions ◽  
The Other ◽  
Rectangular Plates ◽  
Elastic Plates ◽  
Modes Of Vibration ◽  
Ritz’S Method ◽  
Square Plate ◽  
Set Up

Abstract Ritz’s method is one of several possible procedures for obtaining approximate solutions for the frequencies and modes of vibration of thin elastic plates. The accuracy of the results and the practicability of the computations depend to a great extent upon the set of functions that is chosen to represent the plate deflection. In this investigation, use is made of the functions which define the normal modes of vibration of a uniform beam. Tables of values of these functions have been computed as well as values of different integrals of the functions and their derivatives. With the aid of these data, the necessary equations can be set up and solved with reasonable effort. Solutions are obtained for three specific plate problems, namely, (a) square plate clamped at all four edges, (b) square plate clamped along two adjacent edges and free along the other two edges, and (c) square plate clamped along one edge and free along the other three edges.

A Ballast System for Automated Deep-Sea Ascents

2016 ◽  
Author(s):  
Matthias Golz ◽  
Florin Boeck ◽  
Sebastian Ritz ◽  
Gerd Holbach
Keyword(s):  
Environmental Impact ◽  
Environmental Contamination ◽  
Pressure Vessel ◽  
Deep Sea ◽  
Underwater Vehicles ◽  
Compressed Air ◽  
Hydraulic Pump ◽  
Unmanned Underwater Vehicles ◽  
The Past ◽  
Set Up

The efforts to discover the world’s oceans — even in extremely deep-sea environments — have grown more and more in the past years. In this context, unmanned underwater vehicles play a central role. Underwater systems that are not tethered need to provide an apparatus to ensure a safe return to the surface. Therefore, positive buoyancy is required and can be achieved by either losing weight or expanding volume. A conservative method is the dropping of ballast weight. However, nowadays this method is not appropriate due to the environmental impact. This paper presents a ballast system for an automated ascent of a deep-sea seabed station in up to 6000 m depth. The ballast system uses a DC motor driven modified hydraulic pump and a compressed air auxiliary system inside a pressure vessel. With regard to the environmental contamination in case of a leakage, only water is used as ballast fluid. The modification of an ordinary oil-hydraulic radial piston pump and the set-up of the ballast system is introduced. Results from sea trials in the Atlantic Ocean are presented to verify the functionality of the ballast system.

scholarly journals The Reversing Paging Process of Callee in Heterogeneous Networks

2011 ◽  
Vol 1 ◽  
pp. 3-8
Author(s):  
Cong Zhao ◽  
Wei Guo
Keyword(s):  
Heterogeneous Networks ◽  
Mobility Management ◽  
Heterogeneous Network ◽  
Vertical Handoff ◽  
The Past ◽  
The Future ◽  
Wireless Signal ◽  
Set Up

To achieve the goal that anybody could communicate with anyone at anytime in anyplace and in anyway, many technologies, such as GSM、CDMA、WCDMA、CDMA2000、TD-SCDMA、802.11a/b/g and so on, come true in the past years. And now, many B3G or 4G technologies are being studied. It is well-known that the future network would be heterogeneous networks. It is studied in this paper the mobility management of wireless heterogeneous network and a reversing paging process of callee is proposed which integrates paging and handoff. In the process when the caller pages the callee choosing its best suited network on one end, the callee chooses its own best network to begin a reversing paging process to set up the communication. The simulation tells that the proposed process has better performances in the call delay, the call succeeding rate and the wireless signal cost than that of the existing process in which it sets up the call first and then does vertical handoff independently.

scholarly journals The Integration of Radiocarbon Dating in Archaeology

Radiocarbon ◽  
1983 ◽  
Vol 25 (2) ◽  
pp. 639-644 ◽  
Author(s):  
H T Waterbolk
Keyword(s):  
Radiocarbon Dating ◽  
The Other ◽  
New Method ◽  
Time Range ◽  
Traditional Methods ◽  
Radiocarbon Dates ◽  
Fully Integrated ◽  
Expected Time ◽  
The Past

In the past 30 years many hundreds of archaeologic samples have been dated by radiocarbon laboratories. Yet, one cannot say that 14C dating is fully integrated into archaeology. For many archaeologists, a 14C date is an outside expertise, for which they are grateful, when it provides the answer to an otherwise insoluble chronologic problem and when it falls within the expected time range. But if a 14C date contradicts other chronologic evidence, they often find the ‘solution’ inexplicable. Some archaeologists are so impressed by the new method, that they neglect the other evidence; others simply reject problematic 14C dates as archaeologically unacceptable. Frequently, excavation reports are provided with an appendix listing the relevant 14C dates with little or no discussion of their implication. It is rare, indeed, to see in archaeologic reports a careful weighing of the various types of chronologic evidence. Yet, this is precisely what the archaeologist is accustomed to do with the evidence from his traditional methods for building up a chronology: typology and stratigraphy. Why should he not be able to include radiocarbon dates in the same way in his considerations?

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