Magnetism of isolated Mn12 single-molecule magnets detected by magnetic circular dichroism: Observation of spin tunneling with a magneto-optical technique

We report magnetic and magneto-optical measurements of two Mn12 single-molecule magnet derivatives isolated in organic glasses. Field-dependent magnetic circular dichroism (MCD) intensity curves (hysteresis cycles) are found to be essentially identical to superconducting quantum interference device magnetization results and provide experimental evidence for the potential of the optical technique for magnetic characterization. Optical observation of magnetic tunneling has been achieved by studying the decay of the MCD signal at weak applied magnetic field

Identification of Practices, Design, Construction, and Repair Using Trenchless Technology, TR-570, 2010

Trenchless technologies are methods used for the construction and rehabilitation of underground utility pipes. These methods are growing increasingly popular due to their versatility and their potential to lower project costs. However, the use of trenchless technologies in Iowa and their effects on surrounding soil and nearby structures has not been adequately documented. Surveys of and interviews with professionals working in trenchless-related industries in Iowa were conducted, and the results were analyzed and compared to survey results from the United States as a whole. The surveys focused on method familiarity, pavement distress observed, reliability of trenchless methods, and future improvements. Results indicate that the frequency of pavement distress or other trenchless-related issues are an ongoing problem in the industry. Inadequate soil information and quality control/quality assurance (QC/QA) are partially to blame. Fieldwork involving the observation of trenchless construction projects was undertaken with the purpose of documenting current practices and applications of trenchless technology in the United States and Iowa. Field tests were performed in which push-in pressure cells were used to measure the soil stresses induced by trenchless construction methods. A program of laboratory soil testing was carried out in conjunction with the field testing. Soil testing showed that the installations were made in sandy clay or well-graded sand with silt and gravel. Pipes were installed primarily using horizontal directional drilling with pipe diameters from 3 to 12 inches. Pressure cell monitoring was conducted during the following construction phases: pilot bore, pre-reaming, and combined pipe pulling and reaming. The greatest increase in lateral earth pressure was 5.6 psi and was detected 2.1 feet from the centerline of the bore during a pilot hole operation in sandy lean clay. Measurements from 1.0 to 2.5 psi were common. Comparisons were made between field measurements and analytical and finite element calculation methods.

Magnetism of isolated Mn12 single-molecule magnets detected by magnetic circular dichroism: Observation of spin tunneling with a magneto-optical technique

We report magnetic and magneto-optical measurements of two Mn12 single-molecule magnet derivatives isolated in organic glasses. Field-dependent magnetic circular dichroism (MCD) intensity curves (hysteresis cycles) are found to be essentially identical to superconducting quantum interference device magnetization results and provide experimental evidence for the potential of the optical technique for magnetic characterization. Optical observation of magnetic tunneling has been achieved by studying the decay of the MCD signal at weak applied magnetic field

2014 Bowhunter Observation Survey, January 2015

The Iowa Department of Natural Resources (DNR) solicited responses from bow hunters for the annual Bowhunter Observation Survey

Direct Observation of Magnetic Metastability in Individual Iron Nanoparticles

X-ray photoemission electron microscopy combined with x-ray magnetic circular dichroism is used to study the magnetic properties of individual iron nanoparticles with sizes ranging from 20 down to 8 nm. While the magnetocrystalline anisotropy of bulk iron suggests superparamagnetic behavior in this size range, ferromagnetically blocked particles are also found at all sizes. Spontaneous transitions from the blocked state to the superparamagnetic state are observed in single particles and suggest that the enhanced magnetic energy barriers in the ferromagnetic particles are due to metastable, structurally excited states with unexpected life times

Direct Observation of Magnetic Metastability in Individual Iron Nanoparticles

X-ray photoemission electron microscopy combined with x-ray magnetic circular dichroism is used to study the magnetic properties of individual iron nanoparticles with sizes ranging from 20 down to 8 nm. While the magnetocrystalline anisotropy of bulk iron suggests superparamagnetic behavior in this size range, ferromagnetically blocked particles are also found at all sizes. Spontaneous transitions from the blocked state to the superparamagnetic state are observed in single particles and suggest that the enhanced magnetic energy barriers in the ferromagnetic particles are due to metastable, structurally excited states with unexpected life times

Observation touchant le vuide, faite pour la première fois en France , contenue en une lettre écrite à Monsieur Chanut,... Par Monsieur Petit intendant des fortifications, le 10 novembre 1646. Avec le discours qui en a esté imprimé Pologne sur le mesme sujet, en juillet 1647

Comprend : Demonstratio ocularis, Ioci sine locato, corporis successive moti in vacuo...

Forecasting the Earth"s radiation belts and modeling solar energetic particle events: Recent results from SPACECAST

High-energy charged particles in the van Allen radiation belts and in solar energetic particle events can damage satellites on orbit leading to malfunctions and loss of satellite service. Here we describe some recent results from the SPACECAST project on modelling and forecasting the radiation belts, and modelling solar energetic particle events. We describe the SPACECAST forecasting system that uses physical models that include wave-particle interactions to forecast the electron radiation belts up to 3 h ahead. We show that the forecasts were able to reproduce the >2 MeV electron flux at GOES 13 during the moderate storm of 7-8 October 2012, and the period following a fast solar wind stream on 25-26 October 2012 to within a factor of 5 or so. At lower energies of 10- a few 100 keV we show that the electron flux at geostationary orbit depends sensitively on the high-energy tail of the source distribution near 10 RE on the nightside of the Earth, and that the source is best represented by a kappa distribution. We present a new model of whistler mode chorus determined from multiple satellite measurements which shows that the effects of wave-particle interactions beyond geostationary orbit are likely to be very significant. We also present radial diffusion coefficients calculated from satellite data at geostationary orbit which vary with Kp by over four orders of magnitude. We describe a new automated method to determine the position at the shock that is magnetically connected to the Earth for modelling solar energetic particle events and which takes into account entropy, and predict the form of the mean free path in the foreshock, and particle injection efficiency at the shock from analytical theory which can be tested in simulations.

Niobium and rare earth minerals from the Virulundo carbonatite, Namibe, Angola

The Virulundo carbonatite in Angola, one of the biggest in the world, contains pyrochlore as an accessory mineral in all of the carbonatite units (calciocarbonatites, ferrocarbonatites, carbonatite breccias, trachytoids). The composition of the primary pyrochlore crystals is very close to fluornatrocalciopyrochlore in all these units. High-temperature hydrothermal processes caused the pseudomorphic replacement of the above crystals by a second generation of pyrochlore, characterized by lower F and Na contents. Low-temperature hydrothermal replacement of the above pyrochlores, associated with production of quartz-carbonates-fluorite veins, controled the development of a third generation of pyrochlore, characterized by high Sr contents. Finally, supergene processes produced the development of a secondary paragenesis in the carbonatite, consisting in late carbonates, goethite, hollandite and REE minerals (mainly synchysite-(Ce), britholite-(Ce), britholite-(La), cerite-(Ce)). Separation of Ce from the other REE was allowed by oxidizing conditions. Therefore, Ce4+ was also incorporated into a late generation of pyrochlore, which is also strongly enriched in Ba and strongly depleted in Ca and Na

Pregabalin in patients with primary brain tumors and seizures: a preliminary observation.

OBJECTIVES: Patients with brain tumors and seizures should be treated with non-enzyme-inducing antiepileptic drugs (AED). Some of the newer drugs seem particularly suited in these patients. METHODS: Here we describe our experience with pregabalin (PGB); its effectiveness was retrospectively studied in nine consecutive patients with primary brain tumors and seizures. RESULTS: Six subjects had secondarily generalized and three simple partial seizures. Patients mostly suffered from WHO grade IV gliomas. PGB replaced enzyme inducing, inefficacious or bad tolerated AED, as add-on or monotherapy. Median follow-up was 5 (2-19) months; three patients died of their tumor. Daily median dosage was 300 mg. All subjects experienced at least a 50% seizure reduction, six were seizure-free. Side effects were reported in four patients, leading to PGB discontinuation in two. CONCLUSION: PGB appears to have a promising effectiveness in this setting, even as a monotherapy. Based on these results we embarked on a prospective controlled trial.