Optimal procedures for stochastically failing equipment

Optimal procedures for stochastically failing equipmen

Relationship Between Size of Farm Business and Labor Income on Utah Farms

Since the turn of the century there has been a trend within the State of Utah toward more and smaller farms. The original farm units taken up by the early settlers of this state have been divided and subdivided until Utah today has hundreds of uneconomical-sized farms too small to be operated profitably under their present organization. To make room for the new agricultural generation, the old homesteads have been divided among the sons of the families until a farm that was once supporting one family is now unsatisfactorily contributing to the support of several families. This condition has resulted in serious economic and social problems

Mounting of Large Optics for Space Instruments

The light collection capability of an interferometer is dependent on the aperture size of the instrument. Increasing the aperture size can reduce the noise level of the instrument. Instruments that collect light at wavelengths longer than about 15μm often use Potassium Bromide (KBr) beamsplitters. KBr has a high coefficient of thermal expansion (CTE) and low strength, which make it difficult to mount in a robust manner. As a result, many engineers have been hesitant to design their instruments using the full aperture size required for optimal performance. The overall objective of this effort was to examine novel methods of mounting KBr beamsplitters to improve their vibrational, optical, and thermal characteristics. A new thermally engineered composite material (TECMat) was developed that appears to match the CTE of KBr over a wide temperature range. TECMat’s material properties and possible methods of implementing it in beamsplitter mounts are described

Polarity control of carrier injection at ferroelectric/metal interfaces for electrically switchable diode and photovoltaic effects

We investigated a switchable ferroelectric diode effect and its physical mechanism in Pt/BiFeO3/SrRuO3 thin-film capacitors. Our results of electrical measurements support that, near the Pt/BiFeO3 interface of as-grown samples, a defective layer (possibly, an oxygen-vacancy-rich layer) becomes formed and disturbs carrier injection. We therefore used an electrical training process to obtain ferroelectric control of the diode polarity where, by changing the polarization direction using an external bias, we could switch the transport characteristics between forward and reverse diodes. Our system is characterized with a rectangular polarization hysteresis loop, with which we confirmed that the diode polarity switching occurred at the ferroelectric coercive voltage. Moreover, we observed a simultaneous switching of the diode polarity and the associated photovoltaic response dependent on the ferroelectric domain configurations. Our detailed study suggests that the polarization charge can affect the Schottky barrier at the ferroelectric/metal interfaces, resulting in a modulation of the interfacial carrier injection. The amount of polarization-modulated carrier injection can affect the transition voltage value at which a space-charge-limited bulk current-voltage (J-V) behavior is changed from Ohmic (i.e., J ~ V) to nonlinear (i.e., J ~ V^n with n \geq 2). This combination of bulk conduction and polarization-modulated carrier injection explains the detailed physical mechanism underlying the switchable diode effect in ferroelectric capacitors.Comment: Accepted for publication in Phys. Rev.

Niche inheritance: a cooperative pathway to enhance cancer cell fitness though ecosystem engineering

Cancer cells can be described as an invasive species that is able to establish itself in a new environment. The concept of niche construction can be utilized to describe the process by which cancer cells terraform their environment, thereby engineering an ecosystem that promotes the genetic fitness of the species. Ecological dispersion theory can then be utilized to describe and model the steps and barriers involved in a successful diaspora as the cancer cells leave the original host organ and migrate to new host organs to successfully establish a new metastatic community. These ecological concepts can be further utilized to define new diagnostic and therapeutic areas for lethal cancers.Comment: 8 pages, 1 Table, 4 Figure

Alveolar soft-part sarcoma responding to interferon alpha-2b

A 23-year-old woman with an alveolar soft-part sarcoma of her calf with pulmonary metastases unresponsive to chemotherapy is described. Interferon (IFN) alpha-2b induced an impressive tumour response still ongoing after IFN treatment had to be stopped because of a psychosis. An explanation of this effect is still speculativ