Is the phase of plane waves an invariant?

Based on the invariance of the phase of waves, plane waves was shown to propagate with negative frequencies in a medium which moves at superluminal speeds opposite to the propagation direction of plane waves. The validity of the invariance of the phase of plane waves was then called into question. A radical change of the conventional concept of plane waves is recently proposed to solve the problem of negative frequency of waves. Here, we point out flaws in that proposal. Thus, the validity of the invariance of the phase of plane waves remains questionable

Sea level rise adaptation: emerging lessons for local policy development

Many coastal communities across the United States are beginning to plan for climate-related sea level rise. While impacts and solutions will vary with local conditions, jurisdictions which have begun this process seem to pass through three common stages when developing policy for local sea level rise adaptation: l) building awareness about local sea level rise threats, 2) undertaking analyses of local vulnerabilities, and 3) developing plans and policies to deal with these vulnerabilities. The purpose of this paper is to help advance community dialogue and further inform local decision-makers about key elements and steps for addressing climate-related sea level rise. It summarizes the results of a project the Marine Policy Institute (MPI) undertook during 2011-12 to review experiences from fourteen U.S. coastal jurisdictions representing a variety of city, county, and state efforts with sea level adaptation. There are many more initiatives underway than those reflected in this sample, but the “focus jurisdictions” were selected because of the extensive information publically available on their experiences and lessons being learned that could provide insights for coastal communities, especially in Southwest Florida

Junction range finder

Electronic system locates interferences in radar reception. System utilizes well known frequency-modulated continuous-wave technique to locate objects with nonlinear impedances. FM transmitter generates signal through bandpass filter which eliminates higher order harmonics around carrier frequency