Around the third week after gestation in embryonic development, the human heart consists only of a valvless tube, unlike a fully developed adult heart, which is multi-chambered. At this stage in development, the heart valves have not formed and so net flow of blood through the heart must be driven by a different mechanism. It is hypothesized that there are two possible mechanisms that drive blo...

VACUUM PUMPING STUDY OF TITANIUM-ZIRCONIUM-VANADIUM THIN FILMS* Yulin Li and Simon Ho, LEPP, Cornell University, Ithaca, NY 14853, USA Abstract Vacuum pumping via non-evaporable getter (NEG) thin film deposited directly onto the interior of a vacuum chamber is a novel way to achieve extreme high vacuum. As part of R&D efforts for the proposed Energy Recovery Linac at Cornell, the pumping perfor...

In 1950, French physicist Alfred Kastler introduced the concept of modern optical pumping, for which he was awarded the Nobel Prize in 1966. The process of optical pumping involves using photons of a desired wavelength and polarization to change the distribution of a gas of atoms from thermal equilibrium. Today, optical pumping is a critical tool in modern Physics experiments, and is the basis ...

In C. elegans, pharyngeal pumping is regulated by the presence of bacteria. In response to food deprivation, the pumping rate rapidly declines by about 50-60%, but then recovers gradually to baseline levels on food after 24 hr. We used this system to study the role of insulin/IGF-1 signaling (IIS) in the recovery of pharyngeal pumping during starvation. Mutant strains with reduced function in t...

Dial balances are preferred for speed in today's crowded school laboratory. Dial-O-Gram 310 is preferred for speed, accuracy, and the ruggedness which withstands student handling and makes expensive service contracts unnecessary. The unique accuracy of Dial-O-Gram 310 is the result of extensive research by Ohaus on the cause and correction of errors in spiral spring mechanisms. Only Ohaus uses ...

We consider optical pumping with a quasi monochromatic tunable light beam, in the low intensity limit where a rate equation regime is obtained The velocity selective optical pumping (V.S.O.P.) introduces a correlation between atomic velocity and internal variables in the ground (or metastable) state. The aim of this article is to evaluate these atomic observables (orientation, alignment, popula...

PV array is increasingly employed for water pumping system. In this paper, the developed boost converter steps up the voltage produced by the PV array to a value which is suitable to run a single-phase induction motor. The inverter converts DC to AC is controlled by using sinusoidal pulse width modulation (SPWM) technique. By using a LCfilter the harmonics are eliminated and pure sine wave is o...

Froth is the basis to the extraction of bitumen from oil sand. Its components include sand, bitumen, water, and air. The technology of extraction and processing is evolving toward lower temperature of operation where the volumetric content of air and viscosity of bitumen challenge pumping. To improve the efficiency of froth handling pumps it is important to adapt the technology from other indus...

In mechanical studies of pumping a playground swing, two methods of energy insertion have been identified: parametric pumping and driven oscillation. While parametric pumping involves the systematic raising and lowering of the swinger's center of mass (CM) along the swing's radial axis (rope), driven oscillation may be conceived as rotation of the CM around a pivot point at a fixed distance to ...

Rhythmic movements are ubiquitous in animal locomotion, feeding, and circulatory systems. In some systems, the muscle itself generates rhythmic contractions. In others, rhythms are generated by the nervous system or by interactions between the nervous system and muscles. In the nematode Caenorhabditis elegans, feeding occurs via rhythmic contractions (pumping) of the pharynx, a neuromuscular fe...