Specific Surface

Surface area largely determines many physical and chemical properties of materials. Physical adsorption of molecules, heat loss or gain resulting from that adsorption, swelling and shrinking, and many other physical and chemical processes are closely related to surface area. Surface or exposed area is also closely related to and often the controlling factor in many biological processes. Soils vary widely in their reactive surface because of differences in mineralogical and organic composition and in their particle-size distribution. Water retention and movement, cation exchange capacity, and pesticide adsorption are closely related to the specific surface (defined as the surface area per unit mass of soil). Specific surface is usually expressed in square meters per gram (m2/g)

Yield and Quality as Affected by Early and Late Fall and Spring Harvest of Sugarbeets

Sugarbeets (Beta vulgaris L.) in the intermountain areas of the western United States are normally planted in early spring and harvested during October with the advent of cool temperatures. The beet roots during this harvesting period are near their maximum yield and sucrose concentration. Temperatures are cool and suitable for storing excess roots in piles for later processing. The factory processing of beet roots is presently limited to the period between harvest and mid-February after which stored roots in piles deteriorate rapidly in quality with increased temperatures (2, 10, 16, 17). The closing of some sugar factories, and low prices currently received for other crops, has intensified demand by farm managers for increased acreage allotment for sugarbeets. Present low world sugar prices and the uncertainty of continued sugar legislation discourages the expansion of the cutting and processing facilities in factories. Methods and procedures are needed to increase the tonnage of beet roots that can be processed using existing equipment and facilities. The objective of this study was to evaluate methods and procedures where factories can increase the amount of beet roots processed with existing equipment by methods such as early and late fall and spring harvest of sugarbeets

Crop Residue Management for Soil Conservation on Irrigated Lands of the Northwest

Leaving crop residue on the soil surface during cropping has a number of clear advantages over tillage that leaves the soil surface bare. Most obvious is the greatly reduced erosion from wind and water. This advantage alone makes the change worthwhile. Mandated conservation compliance by 1995 is a further incentive to adopt surface crop residue management. Other advantages include increased yield due to water conserved by surface residue, lower soil temperatures, higher quality soil over time due to increased soil organic matter levels, and, in many cases, reduced input of time, labor, and fuel. The feasibility of farming while leaving residues on the surface is indicated by the rapid rate at which farmers are adopting these management practices. Success is due in large part to greater effectiveness and reduced cost of herbicides and the improvement of planting equipment available on the market

Modified Gravity on the Brane and Dark Energy

We analyze the dynamics of an AdS5 braneworld with matter fields when gravity is allowed to deviate from the Einstein form on the brane. We consider exact 5-dimensional warped solutions which are associated with conformal bulk fields of weight -4 and describe on the brane the following three dynamics: those of inhomogeneous dust, of generalized dark radiation, and of homogeneous polytropic dark energy. We show that, with modified gravity on the brane, the existence of such dynamical geometries requires the presence of non-conformal matter fields confined to the brane.Comment: Revised version published in Gen. Rel. Grav. Typos corrected, updated reference and some remarks added for clarity. 11 pages, latex, no figure

Brane World Dynamics and Conformal Bulk Fields

In the Randall-Sundrum scenario we investigate the dynamics of a spherically symmetric 3-brane world when matter fields are present in the bulk. To analyze the 5-dimensional Einstein equations we employ a global conformal transformation whose factor characterizes the $Z_2$ symmetric warp. We find a new set of exact dynamical collapse solutions which localize gravity in the vicinity of the brane for a stress-energy tensor of conformal weight -4 and a warp factor that depends only on the coordinate of the fifth dimension. Geometries which describe the dynamics of inhomogeneous dust and generalized dark radiation on the brane are shown to belong to this set. The conditions for singular or globally regular behavior and the static marginally bound limits are discussed for these examples. Also explicitly demonstrated is complete consistency with the effective point of view of a 4-dimensional observer who is confined to the brane and makes the same assumptions about the bulk degrees of freedom.Comment: 26 pages, latex, no figures. Minor revisions. Some references added. Revised version to appear in Phys. Rev.

Black Holes in Higher-Dimensional Gravity

These lectures review some of the recent progress in uncovering the phase structure of black hole solutions in higher-dimensional vacuum Einstein gravity. The two classes on which we focus are Kaluza-Klein black holes, i.e. static solutions with an event horizon in asymptotically flat spaces with compact directions, and stationary solutions with an event horizon in asymptotically flat space. Highlights include the recently constructed multi-black hole configurations on the cylinder and thin rotating black rings in dimensions higher than five. The phase diagram that is emerging for each of the two classes will be discussed, including an intriguing connection that relates the phase structure of Kaluza-Klein black holes with that of asymptotically flat rotating black holes.Comment: latex, 49 pages, 5 figures. Lectures to appear in the proceedings of the Fourth Aegean Summer School, Mytiline, Lesvos, Greece, September 17-22, 200

Kepler-22b: A 2.4 Earth-radius Planet in the Habitable Zone of a Sun-like Star

A search of the time-series photometry from NASA's Kepler spacecraft reveals a transiting planet candidate orbiting the 11th magnitude G5 dwarf KIC 10593626 with a period of 290 days. The characteristics of the host star are well constrained by high-resolution spectroscopy combined with an asteroseismic analysis of the Kepler photometry, leading to an estimated mass and radius of 0.970 +/- 0.060 MSun and 0.979 +/- 0.020 RSun. The depth of 492 +/- 10ppm for the three observed transits yields a radius of 2.38 +/- 0.13 REarth for the planet. The system passes a battery of tests for false positives, including reconnaissance spectroscopy, high-resolution imaging, and centroid motion. A full BLENDER analysis provides further validation of the planet interpretation by showing that contamination of the target by an eclipsing system would rarely mimic the observed shape of the transits. The final validation of the planet is provided by 16 radial velocities obtained with HIRES on Keck 1 over a one year span. Although the velocities do not lead to a reliable orbit and mass determination, they are able to constrain the mass to a 3{\sigma} upper limit of 124 MEarth, safely in the regime of planetary masses, thus earning the designation Kepler-22b. The radiative equilibrium temperature is 262K for a planet in Kepler-22b's orbit. Although there is no evidence that Kepler-22b is a rocky planet, it is the first confirmed planet with a measured radius to orbit in the Habitable Zone of any star other than the Sun.Comment: Accepted to Ap

Observation of a Coherence Length Effect in Exclusive Rho^0 Electroproduction

Exclusive incoherent electroproduction of the rho^0(770) meson from 1H, 2H, 3He, and 14N targets has been studied by the HERMES experiment at squared four-momentum transfer Q**2>0.4 GeV**2 and positron energy loss nu from 9 to 20 GeV. The ratio of the 14N to 1H cross sections per nucleon, known as the nuclear transparency, was found to decrease with increasing coherence length of quark-antiquark fluctuations of the virtual photon. The data provide clear evidence of the interaction of the quark- antiquark fluctuations with the nuclear medium.Comment: RevTeX, 5 pages, 3 figure

Determination of the Deep Inelastic Contribution to the Generalised Gerasimov-Drell-Hearn Integral for the Proton and Neutron

The virtual photon absorption cross section differences [sigma_1/2-sigma_3/2] for the proton and neutron have been determined from measurements of polarised cross section asymmetries in deep inelastic scattering of 27.5 GeV longitudinally polarised positrons from polarised 1H and 3He internal gas targets. The data were collected in the region above the nucleon resonances in the kinematic range nu < 23.5 GeV and 0.8 GeV**2 < Q**2 < 12 GeV**2. For the proton the contribution to the generalised Gerasimov-Drell-Hearn integral was found to be substantial and must be included for an accurate determination of the full integral. Furthermore the data are consistent with a QCD next-to-leading order fit based on previous deep inelastic scattering data. Therefore higher twist effects do not appear significant.Comment: 6 pages, 3 figures, 1 table, revte

Discharge Estimation From Dense Arrays of Pressure Transducers

In situ river discharge estimation is a critical component of studying rivers. A dominant method for establishing discharge monitoring in situ is a temporary gauge, which uses a rating curve to relate stage to discharge. However, this approach is constrained by cost and the time to develop the stage-discharge rating curve, as rating curves rely on numerous flow measurements at high and low stages. Here, we offer a novel alternative approach to traditional temporary gauges: estimating Discharge via Arrays of Pressure Transducers (DAPT). DAPT uses a Bayesian discharge algorithm developed for the upcoming Surface Water Ocean Topography satellite (SWOT) to estimate in situ discharge from automated water surface elevation measurements. We conducted sensitivity tests over 4,954 model runs on five gauged rivers and conclude that the DAPT method can robustly reproduce discharge with an average Nash-Sutcliffe Efficiency (NSE) of 0.79 and Kling-Gupta Efficiency of 0.78. Further, we find that the DAPT method estimates discharge similarly to an idealized temporary gauge created from the same input data (NSE differences of less than 0.1), and that results improve significantly with accurate priors. Finally, we test the DAPT method in nine poorly gauged rivers in a realistic and complex field setting in the Peace-Athabasca Delta, and show that the DAPT method largely outperforms a temporary gauge in this time and budget constrained setting. We therefore recommend DAPT as an effective tool for in situ discharge estimation in cases where there is not enough time or resources to develop a temporary gauge