Constant net-time headway as key mechanism behind pedestrian flow dynamics

We show that keeping a constant lower limit on the net-time headway is the key mechanism behind the dynamics of pedestrian streams. There is a large variety in flow and speed as functions of density for empirical data of pedestrian streams, obtained from studies in different countries. The net-time headway however, stays approximately constant over all these different data sets. By using this fact, we demonstrate how the underlying dynamics of pedestrian crowds, naturally follows from local interactions. This means that there is no need to come up with an arbitrary fit function (with arbitrary fit parameters) as has traditionally been done. Further, by using not only the average density values, but the variance as well, we show how the recently reported stop-and-go waves [Helbing et al., Physical Review E, 75, 046109] emerge when local density variations take values exceeding a certain maximum global (average) density, which makes pedestrians stop.Comment: 7 pages, 7 figure

A precision sidereal telescope drive based on a solar time crystal clock

A requirement arose for a sidereal drive for a small microwave radiometer on an equatorial mount, the equipment to run unattended to a precision of about 2 minutes in hour angle over a 7-day period. The installation already included a solar-time crystal clock based on a IO MHz oscillator (type HCD 25), which through decade scalers could easily be arranged to operate a standard 50 Hz synchronous motor which would drive the mounting at one revolution per solar day. However, no suitable gearing was available to generate the required sidereal rate

Minnesota Agripower Project, Task IV research report

Economic analysis is being conducted by the Department of Applied Economics in support of Minnesota Alfalfa Producer`s development of alfalfa as a dedicated biomass feedstock for energy production. University Researchers have assisted in the development and implementation of inventory control systems and procedures. This report lists the tasks for which researchers are currently finalizing economic analysis. The tasks encompass three main areas: (1) optimization of feedstock transportation system, (2) analysis of market potential for new alfalfa products, and (3) total systems analysis

Generalized Centrifugal Force Model for Pedestrian Dynamics

A spatially continuous force-based model for simulating pedestrian dynamics is introduced which includes an elliptical volume exclusion of pedestrians. We discuss the phenomena of oscillations and overlapping which occur for certain choices of the forces. The main intention of this work is the quantitative description of pedestrian movement in several geometries. Measurements of the fundamental diagram in narrow and wide corridors are performed. The results of the proposed model show good agreement with empirical data obtained in controlled experiments.Comment: 10 pages, 14 figures, accepted for publication as a Regular Article in Physical Review E. This version contains minor change

Minnesota wheat movements 1979

20 pages; includes maps. This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu

Minnesota grain movements in the seventies: changing trends

61 pages. This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu.Alley, J. Mike; Fruin, Jerry; Eldridge, Chuck. (1982). Minnesota grain movements in the seventies: changing trends. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/169077

Minnesota barley, oats, sunflower, flax, and rye movements 1979

30 pages; includes maps. This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu

Minnesota soybean movements 1979

19 pages; includes maps. This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu

Unit trains and Minnesota grain shipments

19 pages; includes maps. This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu.Eldridge, Chuck; Fruin, Jerry; Alley, J. Mike. (1982). Unit trains and Minnesota grain shipments. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/169078

Minnesota corn movements 1979

23 pages; includes maps. This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu