Polarization spectroscopy of an excited state transition.

We demonstrate polarization spectroscopy of an excited state transition in room-temperature cesium vapor. An anisotropy induced by a circularly polarized pump beam on the D2 transition is observed using a weak probe on the 6P3/2→7S1/2 transition. At high pump power, a subfeature due to Autler-Townes splitting is observed that theoretical modeling shows is enhanced by Doppler averaging. Polarization spectroscopy provides a simple modulation–free signal suitable for laser frequency stabilization to excited state transitions

Modeling the release of CO2 in the deep ocean

The idea of capturing and disposing of carbon dioxide (CO2) from the flue gas of fossil fuel-fired power plants has recently received attention as a possible mitigation strategy to counteract potential global warming due to the "greenhouse effect." One specific scheme is to concentrate the CO2 in the flue gas to over 90 mol %, compress and dehydrate the CO2 to supercritical conditions, and then transport it through a pipeline for deep ocean disposal. In Golomb et al. (1989), this scheme was studied, with emphasis on the CO 2 capture aspects. In this follow-on study, we concentrate on the mechanisms of releasing the CO 2 in the deep ocean.Golomb et al. only considered the release of individual liquid CO 2 droplets in the region below 500 m. In this study, we consider all depths in both the liquid and vapor regions, and we model the entire plume in addition to individual droplets or bubbles. The key design variables in the model that can be controlled are: (1) release depth, (2) number of diffuser ports, N, and (3) initial bubble or droplet radius, ro. The results show that we can lower the height of the plume by increasing the number of diffuser ports and/or decreasing the initial bubble or droplet radius. Figure S-1 summarizes the results for a release depth of 500 m. With reasonable values for N and r. of 10 and 1 cm respectively, we can keep the plume height under 100 m. Since our goal is to dissolve all the CO2 before it reaches the well-mixed surface layer at approximately 100 m, we can release our C02 at depths as shallow as 200 m. However, the residence time of the sequestered CO2 in the ocean is also a function of depth. For releases of CO2 less than 500 m deep, we can estimate a residence time of less than 50 years, and for a release from about 1000 m, a residence time from 200 to 300 years. These residence times may be increased by releasing in areas of downwelling or by forming solid CO 2-hydrates which will sink to the ocean floor. For depths greater than 500 m, CO2-hydrates may form but we have ignored them due to lack of data.We estimate that the local CO2 concentration will increase about 0.2 kg/m 3 . Added to the background concentration of 0.1 kg/m 3 , the resulting total concentration will be about 0.3 kg/m 3 , much less than saturation levels of about 40 kg/m 3 . Similarly, SO2 and NOx concentration increases will be about 1 .10 - 3 kg/m3 and 2 10- 4 kg/m 3 , respectively. Given an ambient current of 10 cm/s, horizontal dispersion will dilute these concentration increases by a factor of two at a distance of about 4 km downstream.In implementing a CO2 capture and sequester scheme based on an air separation/ flue gas recycle power plant, the price of electricity would double. The reasons for this doubling are: (1) 44% due to derating of the power plant because of the parasitic power required to capture C02, mainly for air separation and CO compression, (2) 42% due to capital charges and operation and maintenance costs (excluding fuel) of the power plant modifications, including air separation and CO2 compression, and (3) 14% due to capital charges and operation and maintenance costs of a 160 km pipeline for deep ocean disposal. These numbers assume that no additional control measures are required to mitigate potential environmental problems are associated with deep ocean disposal of CO02.Funded by the Mitsubishi Research Insitute, Society and Technology Dept

The Impact of a Student Advisory Program on School Climate at a Suburban High School

Having a wide variety of students with academic and socially diverse backgrounds could lead to school climate challenges for the students, teachers, and administrators. The purpose of this study was to determine the effect a student advisory program has on the school climate in a suburban high school. This study aimed to answer three research questions. The central research question was: What is the effect of a high school student advisory program on the school climate, students' sense of belonging and connectedness in the school community? The sub-questions related to the central research question are: How does feeling more connected to the school and building relationships influence students' perception of the school climate? How does a student advisory program at a suburban high school enhance the students' sense of belonging? How does networking with other students about the school environment affect the overall school climate? The researcher believes student advisory programs can positively influence a school's climate thus leading to students feeling more connected to their school with an increased sense of belonging. The conceptual framework reviews three themes: student advisory programs, connectedness and building relationships, and school climate.Ed.D., Educational Leadership and Management -- Drexel University, 201

Detrital zircon records of Late Cretaceous syn-rift sedimentary sequences of New Caledonia: an Australian provenance questioned

International audienceThe Late Cretaceous clastic coastal sediments of New Caledonia are contemporaneous with the latest stages of the eastern Australian marginal rifting. As such, they record the erosion of basement terranes located on uplifted and tilted blocks and a contemporaneous volcanic activity. Detrital zircon populations contain two major components, the younger of which is Early Cretaceous, and the older Early Paleozoic and Precambrian. Following recent advances in the knowledge of detrital zircon content of basement terranes, and at variance with previous interpretations, that hypothesised a possible direct Australian provenance for Precambrian zircons, the detrital zircon record of these syn-rift sediments allows a local recycled provenance to be established. In consequence, this new evidence confirms that New Caledonia was already isolated from Australia as early as Coniacian time (ca. 89-85 Ma) a fact consistent with the development of faunal and floral endemism at that period. The prominent abundance of Early Cretaceous detrital zircons also establishes the importance of a previously unrecorded Early Cretaceous magmatism in the area

Magnetostratigraphy and Clockwise Rotation of the Plio-Pleistocene Mojave River Formation, Central Mojave Desert, California

Oriented samples collected for paleomagnetic analysis from sediments of the newly-named Mojave River Formation (Nagy & Murray, 1991, this volume) possess stable characteristic components of Natural Remanent Magnetization (NRM). Progressive demagnetization reveals characteristic components of both normal and reversed polarity which are stratigraphically distinct. The oldest sediments exposed within the field area are reversely magnetized and were probably deposited during the early portion of the Matuyama reversed Chron. Stratigraphically higher units contain what appears to be the Olduvai normal Subchron, as well as a shorter normal zone which probably is either the Cobb Mountain or Jaramillo Event. The location of the Brunhes/Matuyama boundary at one site is within an alluvial fanglomerate which grades upward conformably into the lowest unit of the overlying Manix Formation, possibly accounting for the absence of the Bishop ash in the section. Demagnetization data from 143 samples yielding acceptable least-squares lines suggest a net clockwise rotation of 8 ± 2.7° over the past two million years, perhaps with some of the rotation during deposition. This rate of rotation could account easily for larger rotations reported elsewhere in the Mojave Desert on units of Miocene age

Di-μ-chlorido-bis­[dichlorido(3,3′,5,5′-tetra­methyl-4,4′-bipyrazol-1-ium-κN 2′)copper(II)] dihydrate

The structure of the centrosymmetric title compound, [Cu2Cl6(C10H15N4)2]·2H2O, consists of a dimeric [{(HMe4bpz)CuCl3}2] unit (HMe4bpz is 3,3′,5,5′-tetra­methyl-4,4′-bipyrazol-1-ium) with two solvent water molecules. Each [HMe4bpz]+ cation is bonded to a CuCl3 unit through a Cu—N dative bond, effectively making square-planar geometry at the Cu atom. Two of these units then undergo a face-to-face dimerization so that the Cu atoms have a Jahn–Teller distorted square-pyramidal geometry with three chlorides and an N atom in the basal plane and one chloride weakly bound in the apical position. Several N—H⋯Cl, O—H⋯Cl and N—H⋯O hydrogen bonds form a three-dimensional network