Complex permeability of soft magnetic ferrite polyester resin composites at frequencies above 1 MHz

Composite soft magnetic materials consist of magnetic particles in a non-magnetic matrix. The properties of such materials can be modelled using effective medium theory. Measurements have been made of the complex permeability of composites produced using ferrite powder and polyester resin. The success of various effective medium expressions in predicting the variation of complex permeability with composition has been assessed

Helicopter Anti-Torque System Using Strakes

A helicopter is disclosed with a system for controlling main-rotor torque which reduces the power and size requirements of conventional anti-torque means. The torque countering forces are generated by disrupting the main rotor downwash flowing around the fuselage. The downwash flow is separated from the fuselage surface by a strake positioned at a specified location on the fuselage. This location is determined by the particular helicopter wash pattern and fuselage configuration, generally being located between 20 deg before top dead center (TDC) and 80 deg from TDC on the fuselage side to which the main rotor blade approaches during rotation. The strake extends along the fuselage from the cabin section to the aft end and can be continuous or separated for aerodynamic surfaces such as a horizontal stabilizer

High School Block Scheduling As a Stimulus: A Multiple-site Case Study

The purpose of this study was to identify the processes that have been used for implementing the alternative scheduling plan of block scheduling in high schools. The study attempted to discover what professional development activities were used for the change, if teachers altered instruction, and what additional staff development was needed. The qualitative method of case study research was selected for the study. The investigator chose five public high schools, representing city and county systems and different professional development budgets and types of instructional support. Central office administrators who were responsible for the implementation of block scheduling, principals, and a purposeful sample of teachers were interviewed. Utilizing interview transcripts, field notes, and records, case studies were formulated for each school. A cross-site analysis was also developed. This aspect of the study focused on several themes that emerged from the case studies. These themes included reasons for the scheduling change; implementation procedures; professional development strategies; effects on instruction, students, and schools; and procedural and staff development needs. The conclusions of the study were as follows: a concern for students prompted the change; considerable effort was devoted to implementation; the 4 x 4 semester plan was the most common configuration; a considerable difference existed in the amounts schools spent for professional development; and staff development was integral to implementation. Additional conclusions were that block scheduling had both positive and negative effects on instruction; some teachers altered instruction with the schedule; the majority of students preferred a block schedule instead of a traditional one; the plan had a positive impact on the discipline, course offerings, and learning atmosphere of a school; and changes in implementation and professional growth would enhance the innovation. These conclusions will assist educators in developing and implementing procedural strategies and professional development plans for block scheduling, as well as other reform efforts

Scaredy-Cat

Now you run out and play. You can\u27t mope around the house all day. His mother shooed him out the door..

A research program in determination of heavy metals in sediments and benthic species in relation to nuclear power plant operation

Heavy metals in the estuarine environment can be toxic to fish and shellfish early life history stages and concentrations build up to levels of concern in marketable shellfish. The present survey was begun just before startup in 1974 of the 1900 megawatt Calvert Cliffs Nuclear Power Plant on the Chesapeake Bay in order to assess and understand factors relating to heavy metal accumulation in estuarine biota. Oysters were collected in large numbers at test and reference sites in June 1974 to 77 and individually analyzed for copper and zinc. Oyster copper and zinc concentrations were correlated with salinity read at time of collection. The relationship of oyster age to metal concentration was examined with two sets of oysters of known age and genetic origin (laboratory spawned). Copper sorption by typical mid Bay sediments, and field studies on cadmium concentrations in sediments were examined

Climate Change, the Knowledge Problem and the Good Life

This paper will argue that we must address the challenge of climate change through the prism of what is called the knowledge problem and—no less important—from the perspective of the good life. When discussing our society’s big problems, there is a tendency to assume that we have the knowledge we will require to act on the problems before us. And there is a tendency to presume that the intentions of our actions will translate seamlessly to the desired consequences. Knowledge problems are why both these assumptions can be wrong – and why they can lead to unintended outcomes, some of them disastrous. This paper will briefly outline some of the problems with our knowledge of climate and energy systems, and how these problems can affect planning and policies on climate change, before discussing how these plans and policies come to bear on the conception of the good life. The case of biofuels policies will be used as an illustration of these problems

Laser gas-discharge absorption measurements of the ratio of two transition rates in argon

The ratio of two line strengths at 922.7 nm and 978.7 nm of argon is measured in an argon pulsed discharge with the use of a single-mode Ti:Sapphire laser. The result 3.29(0.13) is in agreement with our theoretical prediction 3.23 and with a less accurate ratio 2.89(0.43) from the NIST database.Comment: 5 pages, 2 figures, 1 tabl