2,130 research outputs found
Petrologic study of the Murrysville sandstone in southwestern Pennsylvania
Pennsylvania\u27s Murrysville sandstone has been a proven gas producer since 1859 and a gas storage field since 1951. Using 49 side-wall cores from a gas well drilled in Westmoreland County, depositional environment and diagenesis are examined. In thin section, 5 microfacies are recognized. The lower two-thirds of the Murrysville is equivalent to the Cussewago of northwestern Pennsylvania and is interpreted as fluvial deltaic. The upper third is equivalent to the Berea of Ohio and is interpreted as being a marine transitional stream deposit.;Compaction was not extensive due to low amounts of ductile grains, rigid grain stability and matrix occupying space between grains. Chlorite cement, most commonly in the form of radiating needles, inhibited other cements and preserved primary porosity. Quartz cement, calcite cement and siderite cement are also present, quartz being the most abundant cement. Secondary porosity is present as moldic and intragranular porosity. Feldspars and rock fragments were most commonly leached. Permeability values ranged from 0.005 to nearly 1000 millidarcies
Proximate Composition of Seed and Biomass from Soybean Plants Grown at Different Carbon Dioxide (CO2) Concentrations
Soybean plants were grown for 90 days at 500, 1000, 2000, and 5000 ubar (ppm) carbon dioxide (CO2) and compared for proximate nutritional value. For both cultivars (MC and PX), seed protein levels were highest at 1000 (39.3 and 41.9 percent for MC and PX) and lowest at 2000 (34.7 and 38.9 percent for MC and PX). Seed fat (oil) levels were highest at 2000 (21.2 and 20.9 percent for MC and PX) and lowest at 5000 (13.6 and 16.6 percent for MC and PX). Seed carbohydrate levels were highest at 500 (31.5 and 28.4 percent for MC and PX) and lowest at 2000 (20.9 and 20.8 percent for MC and PX). When adjusted for total seed yield per unit growing area, the highest production of protein and carbohydrate occurred with MC at 1000, while equally high amounts of fat were produced with MC at 1000 and 2000. Seed set and pod development at 2000 were delayed in comparison to other CO2 treatments; thus the proportionately high fat and low protein at 2000 may have been a result of the delay in plant maturity rather than CO2 concentration. Stem crude fiber and carbohydrate levels for both cultivars increased with increased CO2. Leaf protein and crude fiber levels also tended to rise with increased CO2 but leaf carbohydrate levels decreased as CO2 was increased. The results suggest that CO2 effects on total seed yield out-weighed any potential advantages to changes in seed composition
Effects of elevated atmospheric carbon dioxide concentrations on water and acid requirements of soybeans grown in a recirculating hydroponic system
Establishing mass budgets of various crop needs, i.e. water and nutrients, in different environments is essential for the Controlled Ecological Life Support System (CELSS). The effects of CO2 (500 and 1000 umol mol (exp -1)) on water and acid use (for pH control) by soybeans in a recirculating hydroponic system were examined. Plants of cvs. McCall and Pixie were grown for 90 days using the nutrient film technique (NFT) and a nitrate based nutrient solution. System acid use for both CO2 levels peaked near 4 weeks during a phase of rapid vegetative growth, but acid use decreased more rapidly under 500 compared to 1000 umol mol (exp GR) CO2. Total system water use by 500 and 1000 umol mol (exp -1) plants was similar, leaving off at 5 weeks and declining as plants senesced (ca. 9 weeks). However, single leaf transpiration rates were consistently lower at 1000 umol mol (exp -1). The data suggest that high CO2 concentrations increase system acid (and nutrient) use because of increased vegetative growth, which in turn negates the benefit of reduced water use (lower transpiration rates) per unit leaf area
Self-similar transmission properties of aperiodic Cantor potentials in gapped graphene
We investigate the transmission properties of quasiperiodic or aperiodic
structures based on graphene arranged according to the Cantor sequence. In
particular, we have found self-similar behaviour in the transmission spectra,
and most importantly, we have calculated the scalability of the spectra. To do
this, we implement and propose scaling rules for each one of the fundamental
parameters: generation number, height of the barriers and length of the system.
With this in mind we have been able to reproduce the reference transmission
spectrum, applying the appropriate scaling rule, by means of the scaled
transmission spectrum. These scaling rules are valid for both normal and
oblique incidence, and as far as we can see the basic ingredients to obtain
self-similar characteristics are: relativistic Dirac electrons, a self-similar
structure and the non-conservation of the pseudo-spin. This constitutes a
reduction of the number of conditions needed to observe self-similarity in
graphene-based structures, see D\'iaz-Guerrero et al. [D. S. D\'iaz-Guerrero,
L. M. Gaggero-Sager, I. Rodr\'iguez-Vargas, and G. G. Naumis,
arXiv:1503.03412v1, 2015]
Nutritional Quality of \u3ci\u3eDigitaria eriantha Steudel.\u3c/i\u3e Subsp. \u3ci\u3eEriantha\u3c/i\u3e cv. \u3ci\u3eIrene\u3c/i\u3e
Digitaria eriantha is a South African perennial grass, C4 type, that grows during spring and summer with rainfalls higher than 400mm. The aim of this paper was to evaluate its nutritional quality profile: Crude Protein (%CP), True Protein (%TP), Soluble Protein (%SP), Non-Protein Nitrogen (%NPN), Neutral Detergent Fiber (%NDF) and Acid Detergent Fiber (%ADF) in cumulative production cuttings during a species cycle. In-sacco technique was applied to estimate the degradability of dry matter (DM). A simple regression statistics method was applied to relate different nutritional parameters. Digitaria eriantha presents low percentage of CP from flowering and of NPN during its whole cycle. TP represents more than 40% of CP. The estimated effective degradability is lower than the determined with in-sacco technique and it is related to the increase of NDF and ADF and with decrease of the TP as cycle progresses
Effects of atmospheric CO2 on photosynthetic characteristics of soybean leaves
Soybean (Glycine max. cv. McCall) plants were grown at 500, 1000, and 2000 umol mol (exp -1) CO2 for 35 days with a photosynthetic photon flux of 300 umol m (exp -2) s (-1). Individual leaves were exposed to step changes of photosynthetic photon flux to study CO2 assimilation rates (CAR), i.e., leaf net photosynthesis. In general, CAR increased when CO2 increased from 500 to 1000 umol mol (exp -1), but not from 1000 to 2000 umol mol (exp -1). Regardless of the CO2 level, all leaves showed similar CAR at similar CO2 and PPF. This observation contrasts with reports that plants tend to become 'lazy' at elevated CO2 levels over time. Although leaf stomatal conductance (to water vapor) showed diurnal rhythms entrained to the photoperiod, leaf CAR did not show these rhythms and remained constant across the light period, indicating that stomatal conductance had little effect on CAR. Such measurements suggest that short-term changes in CO2 exchange dynamics for a controlled ecological life support system can be closely predicted for an actively growing soybean crop
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