SELF-OSCILLATING INDUCTION HEATER

This report develops a control system to keep an induction heater in resonance. When a metallic workpiece is inserted in the air core of the workcoil, the resonant frequency changes. Different workpiece materials affect the resonant frequency and power. This presents a problem since changing the resonant frequency of the circuit while keeping the frequency constant reduces the maximum power of the circuit. Finite element analysis is used to find the circuit parameters of the workcoil and workpiece interaction. A non-linear controller which oscillates based on the resonant frequency of an LC tank is created. Nyquist and describing function analysis is used to find sustained oscillation points of the circuit. A hardware induction heater with a non-linear controller is created to prove the design

Cytomegalovirus (CMV) in pregnancy

This issue of eMedRef provides information to clinicians on the pathophysiology, diagnosis, and therapeutics of cytomegalovirus in pregnancy

Analysis of permanent magnets as elasmobranch bycatch reduction devices in hook-and-line and longline trials

Previous studies indicate that elasmobranch fishes (sharks, skates and rays) detect the Earth’s geomagnetic field by indirect magnetoreception through electromagnetic induction, using their ampullae of Lorenzini. Applying this concept, we evaluated the capture of elasmobranchs in the presence of permanent magnets in hook-and-line and inshore longline fishing experiments. Hooks with neodymium-iron-boron magnets significantly reduced the capture of elasmobranchs overall in comparison with control and procedural control hooks in the hook-and-line experiment. Catches of Atlantic sharpnose shark (Rhizoprionodon terraenovae) and smooth dogfish (Mustelus canis) were signif icantly reduced with magnetic hook-and-line treatments, whereas catches of spiny dogfish (Squalus acanthias) and clearnose skate (Raja eglanteria) were not. Longline hooks with barium-ferrite magnets significantly reduced total elasmobranch capture when compared with control hooks. In the longline study, capture of blacktip sharks (Carcharhinus limbatus) and southern stingrays (Dasyatis americana) was reduced on magnetic hooks, whereas capture of sandbar shark (Carcharhinus plumbeus) was not affected. Teleosts, such as red drum (Sciaenops ocellatus), Atlantic croaker (Micropogonias undulatus), oyster toadfish (Opsanus tau), black sea bass (Centropristis striata), and the bluefish (Pomatomas saltatrix), showed no hook preference in either hook-and-line or longline studies. These results indicate that permanent magnets, although eliciting species-specific capture trends, warrant further investigation in commercial longline and recreational fisheries, where bycatch mortality is a leading contributor to declines in elasmobranch populations

Visions of Quality Assurance in Online MBA Programs

Online MBA programs have undergone significant growth in recent years. However, quality assurance measures have not kept pace with this growth. The purpose of this study was to identify and prioritize aspects of quality assurance specific to Association to Advance College Schools of Business (AACSB)-accredited online MBA programs. The Delphi methodology was used to facilitate a group conversation among administrators, faculty members, and instructional designers around the topic of quality assurance for online Master of Business Administration (MBA) programs over the next 3-5 years. This paper reports the results of this study and how the results will help to direct the efforts of those involved in the delivery of a quality online MBA program

A Survey of Dairy Farm Treatment Practices on Midwest Dairy Farms

Judicious antimicrobial use and antimicrobial stewardship have become buzzwords in production animal agriculture over the last few years. While these words are becoming expectations in the industry, very little is understood about their true meaning and the level of implementation of judicious use practices on dairy farms. We conducted an investigation on 85 dairy farms in the Midwest to document drug use practices on these farms. Our results indicate that most farms are doing an adequate job of implementing judicious practices, but there is room for improvement to meet expectations of regulatory officials and consumers

The Effect of Confinement on Fe2O3 Nanoparticles in Free Diffusion and with a Horizontal Magnetic Field

We investigated the magnitude of the confinement effect\u27s influence on the free diffusion of Iron Oxide Fe2O3 in pure water contained in cells of different volumes and also that of an applied magnetic field. A shadowgraph apparatus consisting of a super luminous diode (SLD) source, a CCD camera, and achromatic lenses was used to record and analyze the changing indices of refraction due to the presence of concentration-driven fluctuations as the solution diffuses. Extracted frames from this recording were processed through a Differential Dynamic Algorithm (DDA) that determined the dynamics of the process, such as the structure function. The results generated by the DDA was further analyzed to determine how the amplitude of concentration fluctuations change over time and how long those fluctuations are present, revealing a dependency of the dynamics on the size of the cell containing the solution

Can Circle Hook Use Benefit Billfishes?

We performed a quantitative review to evaluate circle hook use in recreational and commercial hook-and-line fisheries that interact with billfishes (Family: Istiophoridae). Specifically, we scrutinized the findings of 11 recent empirical studies that reported, on a species-specific basis, side-by-side measures of circle vs. J-hook fishing performance: catch, mortality, deep-hooking and bleeding rates. Of the 30 total comparisons extracted from the literature that satisfied our inclusion criteria, 13 indicated significant differences between hook types for the specific metric compared. No study reported significant billfish catch rate differences between hook types. However, when significant differences between hook types were found, higher mortality rates and higher rates of deep-hooking and bleeding were associated with J-hooks relative to circle hooks. We conclude that empirical evidence is sufficient to promote circle hook use in almost all hook-and-line fishery sectors that typically interact with istiophorids. However, billfish conservation benefits will only be realized if fishers use unmodified circle hooks, commit to releasing live fish and take other appropriate measures which maximize post-release survival. While there may be fishing modes where circle hook effects are negative, for billfish conservation, we recommend managers grant exceptions to circle hook use only when experimental results support such a practice