Michigan Technological University

About: Michigan Technological University is a education organization based out in Houghton, Michigan, United States. It is known for research contribution in the topics: Population & Volcano. The organization has 8023 authors who have published 17422 publications receiving 481780 citations. The organization is also known as: MTU & Michigan Tech.

Flood Frequency Analysis in the United States: Time to Update

Abstract: A large portion of the U.S. population, infrastructure, and industry is located in flood-prone areas. As a result, floods cause an average of nearly 140 deaths and cost roughly $6 billion annually excluding flooding caused by Hurricane Katrina, which cost $200 billion alone www.usgs.gov/hazards/floods/; USGS 2006 . The 1993 Midwest flooding along the Mississippi and Missouri Rivers caused $20 billion in damages. Furthermore, these estimates neglect the real costs associated with loss of personal possessions and shattered lives and communities. With Hurricane Katrina August 2005 and recent floods in the Northeast June 2006 , Ohio winter 2007 , Texas–Oklahoma June 2007 , and central England July 2007 , it seems like damaging floods have been in the news daily over the last few years. While engineers cannot stop floods from occurring, they should seek structural and nonstructural strategies to reduce the risk of large economic losses, social vulnerability, environmental damage, and loss of life IFMRC 1994 . Development of economically efficient and rational plans requires good estimates of the risk of flooding. In the United States, that computation is done following guidelines in Bulletin 17, for which the latest update, Bulletin 17B, was published in 1982 IACWD 1982 . That update includes the skew map published 30 years ago in the original Bulletin 17 WRC 1976 , and a list of areas needing additional research. Bulletin 17B has served the nation for over 30 years; it is a remarkable document that has withstood the test of time and use. However, given long-standing problems listed in the document, recent advances that address those problems, and the current national interest in flood risk, the time has arrived to update Bulletin 17B to maintain the statistical credibility of the guidelines and to provide accurate risk and uncertainty assessments.

Battle of the Water Calibration Networks

Abstract: Calibration is a process of comparing model results with field data and making the appropriate adjustments so that both results agree. Calibration methods can involve formal optimization methods or manual methods in which the modeler informally examines alternative model parameters. The development of a calibration framework typically involves the following: (1) definition of the model variables, coefficients, and equations; (2) selection of an objective function to measure the quality of the calibration; (3) selection of the set of data to be used for the calibration process; and (4) selection of an optimization/manual scheme for altering the coefficient values in the direction of reducing the objective function. Hydraulic calibration usually involves the modification of system demands, fine-tuning the roughness values of pipes, altering pump operation characteristics, and adjusting other model attributes that affect simulation results, in particular those that have significant uncertainty assoc...

Signaling Strategies for the Hybrid MIMO Phased-Array Radar

Abstract: The hybrid MIMO phased array radar (HMPAR) is a notional concept for a multisensor radar architecture that combines elements of traditional phased-array radar with the emerging technology of multiple-input multiple output (MIMO) radar. A HMPAR comprises a large number, MP, of T/R elements, organized into M subarrays of P elements each. Within each subarray, passive element-level phase shifting is used to steer transmit and receive beams in some desired fashion. Each of the M subarrays are in turn driven by independently amplified phase-coded signals which could be quasi-orthogonal, phase-coherent, or partially correlated. Such a radar system could be used in an airborne platform for concurrent search, detect, and track missions. This paper considers various signaling strategies which could be employed in the notional HMPAR architecture to achieve various objectives quantified by transmit beampatterns and space-time ambiguity functions. First, we propose a method to generate multiple correlated signals for uniform linear and rectangular arrays that achieve arbitrary rectangular transmit beampatterns in one and two dimensions, while maintaining desirable temporal properties. Examples of the range of transmit beampatterns possible with this technique are illustrated for an array of MP=900 elements, arranged using different values of M and P. Then the space-time, or MIMO, ambiguity function that is appropriate for the HMPAR radar system is derived. Examples of ambiguity functions for our signals using a one-dimensional HMPAR architecture are given, demonstrating that one can achieve phased-array-like resolution on receive, for arbitrary transmit beampatterns.

Consensus Guidance for Banking and Supply of Human Embryonic Stem Cell Lines for Research Purposes

Abstract: The work on human embryonic stem cells is being performed with a variety of cell lines using a variety of culture conditions; a situation that makes standardisation between projects and publications very difficult. Clearly the consequence of using such cells would be wasted time and resources but, more seriously, the generation of erroneous data in the literature which could both confuse and delay scientific progress in this area. This guidance document represents the outcome of the first meeting of the group named The International Stem Cell Banking Initiative held in October 2007. The document has been prepared from the perspective of hESC culture but, in many respects, is broadly applicable to all human stem cell lines including induced pluripotent stem cell lines.

Mechanical deformation of dendrites by fluid flow

Abstract: It is generally accepted that liquid agitation during alloy solidification assists in crystal multiplication, as in dendrite fragmentation and the detachment of side arms in the mushy region of a casting. Even without deliberate stirring by electromagnetic or mechanical means, there is often vigorous interdendritic fluid flow promoted by natural thermosolutal convection. Interdendritic fluid flow rates in metals might be as high as 10 mm s{sup {minus}1}. It is the purpose of this article to examine whether such fluid flow can cause mechanical deformation of dendrites, sufficient to cause side arms to bend or break. Metals are so ductile at their melting points that applied forces could only be expected to cause bending, as opposed to fracture, although there are no reports of which the authors are aware of dendritic arms being mechanically bent in this way. The following estimates demonstrate why even bending is not to be expected. In this analysis, the authors shall estimate the stress at the root of a secondary dendrite arm of aluminum arising from the action of a flow of molten metal past the dendrite arm.