Diffusion-Linked Microbial Metabolism in the Vadose Zone

1999 ◽  
Author(s):  
J. E. Watson ◽  
R. F. Harris
Keyword(s):  
Vadose Zone ◽  
Plant Biomass ◽  
Higher Plants ◽  
High Energy ◽  
Essential Elements ◽  
Biofilm Reactor ◽  
Plant Residues ◽  
Soil Organisms ◽  
Transport And Transformation ◽  
Low Energy Electrons

Figure 7.1 is a schematic of nutrient and contaminant transformations and cycling in the vadose zone. As detailed in Harris and Arnold (1995), higher plants take up C, N, P, and S in their most oxidized forms and use, via photosynthesis, the Sun’s energy and low-energy electrons from the oxygen in water to convert the oxidized forms of these essential elements into the relatively high energy reduced forms comprising plant biomass. Following plant death, the biomass residues enter the soil and are attacked by soil organisms as a source of food. The plant residues are depolymerized and the reduced, high-energy monomers are assimilated in part into soil organism biomass, and in part are used as electron donors to combine with the most thermodynamically efficient electron acceptors for dissimilatory energy generation to drive growth and maintenance reactions. In aerobic zones, oxygen is the preferred electron acceptor as long as it is nonlimiting. Death of soil organisms produces dead biomass which re-enters the biological reactor. Ultimately, via respiration in aerobic soils, all the reduced C, N, P, and S materials are released as their oxidized forms, and oxygen is reduced to water to complete the cycle. Ideally, the cycle is conservative, particularly from the standpoint of nonleakage of nutrients, such as nitrate, into the groundwater. Similarly, contaminants entering the vadose zone, either as a function of agronomic use or by accident, should ideally be integrated into the natural nutrient cycles and converted to harmless by-products for assimilation and dissimilation by soil organisms and higher plants (Liu, 1994). Management of nutrient and contaminant transformations by the soil organisms requires a thorough understanding of the ecophysiological and solute transport ground rules that control the nature and rates of transformation options available to the soil organisms. In models of chemical transport and transformation through the vadose zone, colonies of microorganisms are frequently treated as a homogeneous biofilm reactor (Grant and Rochette, 1994). Often, modeling efforts are focused on environmental conditions external to the microbial colony. This consideration of the colony as a biofilm with relatively constant nutrient uptake rates ignores the growth differentiation that occurs as the colony develops

scholarly journals Proof of concept of wastewater treatment via passive aeration SND using a novel zeolite amended biofilm reactor

2018 ◽  
Vol 78 (10) ◽  
pp. 2204-2213 ◽  
Author(s):  
Liang Cheng ◽  
Raphael Marie-Guillaume Flavigny ◽  
Md Iqbal Hossain ◽  
Wipa Charles ◽  
Ralf Cord-Ruwisch
Keyword(s):  
Oxygen Supply ◽  
Energy Requirement ◽  
Operation Mode ◽  
High Energy ◽  
Biofilm Reactor ◽  
Low Energy ◽  
Treated Wastewater ◽  
Synthetic Wastewater ◽  
Bulk Solution ◽  
Nutrient Removal Efficiency

Abstract The current paper describes a novel passive aeration simultaneous nitrification and denitrification (PASND) zeolite amended biofilm reactor that removes organic carbon and nitrogen from wastewater with low-energy consumption. Next to the ammonium oxidizing bacteria (AOB), this reactor contained naturally enriched glycogen accumulating organisms (GAOs) and zeolite powder to initially adsorb BOD (acetate) and ammonium (NH4+-N) from synthetic wastewater under anaerobic conditions. Draining of the treated wastewater exposed the biofilm directly to air enabling low-energy oxygen supply by passive aeration. This allowed the adsorbed ammonium to be oxidized by the AOB and the produced nitrite and nitrate to be reduced simultaneously by the GAOs using the adsorbed BOD (stored as PHAs) as carbon source. Overall, with an operation mode of 1 h anaerobic and 4 h aerobic phase, the nutrient removal efficiency after single treatment was about 94.3% for BOD and 72.2% for nitrogen (NH4+-N). As high-energy aeration of the bulk solution for oxygen supply is completely avoided, the energy requirement of the proposed PASND biofilm reactor can be theoretically cut down to more than 50% compared to the traditional activated sludge process.

Sucrose synthesis in higher plants and high energy phosphate

1952 ◽  
Vol 8 ◽  
pp. 478-479
Author(s):  
B.J.D. Meeuse ◽  
Atie Van Der Eijk ◽  
H.E. Latuasan
Keyword(s):  
Higher Plants ◽  
High Energy ◽  
Sucrose Synthesis ◽  
High Energy Phosphate

scholarly journals Producción de Hidrógeno mediante digestión anaerobia de residuos de planta de jitomate

2019 ◽  
pp. 1-12
Author(s):  
Sarai Camarena-Martínez ◽  
Juan Humberto Martínez-Martínez ◽  
Adriana Saldaña-Robles ◽  
Graciela M.L Ruiz-Aguilar
Keyword(s):  
Hydrogen Production ◽  
Tomato Plant ◽  
Biological Process ◽  
Clean Energy ◽  
High Energy ◽  
Anaerobic Sludge ◽  
Plant Residues ◽  
Lignocellulosic Waste ◽  
Initial Ph ◽  
Native Microflora

Hydrogen (H2) is recognized as a promising energy carrier among the alternatives for obtaining clean energy, since it has a high energy efficiency (122 kJ / g) and can be obtained from lignocellulosic waste through a biological process. In the state of Guanajuato, high amounts of plant waste derived from tomato cultivation are generated because this is the crop mostly produced through protected agriculture. So, the objective of the present study was to consider tomato plant residues for the generation of hydrogen through the anaerobic digestion process. Two sources of inoculum, native microflora of the tomato plant and anaerobic sludge pretreated at 100 ° C for 24 h; and four mineral media at an initial pH of 6.5 ± 0.2 in batch experiments, were evaluated. The highest yield was 37.4 mLH2 / g SV using native microflora and mineral media with yeast extract. Hydrogen production was found like those reported in the literature for other type of waste, highlighting the no-need to pretreat the substrate or inoculum. Therefore, the methodology propose is efficient to the hydrogen production from tomato plant residues.

scholarly journals Carbohydrate and Amino Acid Profiles of Cotton Plant Biomass Products

Agriculture ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 2 ◽  
Author(s):  
Zhongqi He ◽  
Dan C. Olk ◽  
Haile Tewolde ◽  
Hailin Zhang ◽  
Mark Shankle
Keyword(s):  
Amino Acids ◽  
Cotton Plant ◽  
Management Practices ◽  
Plant Biomass ◽  
Plant Residues ◽  
Cotton Leaf ◽  
Essential Information ◽  
Plant Parts ◽  
Processing Strategies ◽  
Biomass Materials

To achieve the optimal and diverse utilization of cotton (Gossypium hirsutum) plant residues in various agricultural, industrial, and environmental applications, the chemical composition of cotton biomass tissues across different plant parts (e.g., seed, boll, bur, leaves, stalk, stem, and root) is of essential information. Thus, in this work, we collected field-grown whole mature cotton plants and separated them into distinct biomass fractions including main stems, leaf blades, branches, petioles, roots, and reproductive parts (mid-season growth stage) or bur, peduncles/bract, and seed cotton (pre-defoliation stage). The contents of selected carbohydrates and amino acids in these cotton biomass materials were determined. Both essential and nonessential amino acids were enriched in cotton leaf blades and reproductive parts. The distribution pattern of the selected carbohydrates differed from that of amino acids—higher contents of carbohydrate were found in roots, main stems, and branches. Although glucose was the most abundant non-structural carbohydrate in cotton plant parts at mid-season, xylose was the most abundant in most plant parts at the pre-defoliation stage. Nutritional carbohydrates and amino acids were further accumulated in seeds at pre-defoliation. The information reported in this work would be helpful in exploring and optimizing management practices and processing strategies for utilizing cotton crop biomass materials as valuable and renewable natural resources.

A Black Box Design Approach to Avian-Inspired SMA Coil Actuated Wearable Morphing Angel Wings

2017 ◽  
Author(s):  
Sean Dalton ◽  
Henry Koon ◽  
Jennifer O’Malley ◽  
Julianna Abel
Keyword(s):  
High Energy ◽  
Essential Elements ◽  
Black Box ◽  
Design Approach ◽  
High Energy Density ◽  
Parameter Study ◽  
University Of Minnesota ◽  
Theatre Arts ◽  
Closed Span ◽  
Actuator System

Black box design is a constraint driven design approach that distills essential elements of a physical process into inputs and outputs. This paper details the black box design implementation and validation of shape memory alloy (SMA) coil actuators as active members in a Watt I six bar avian-inspired wearable morphing angel wing mechanism. SMA coil actuators leverage the unique characteristics of high energy density SMA wire by providing a compact structural platform for large actuation displacement applications. The moderate force and displacement performance of low spring index coil actuators paired with their virtually silent actuation performance made them an attractive actuator solution to an avian-inspired wearable morphing wing mechanism for the University of Minnesota Department of Theatre Arts and Dance production of ‘Marisol’. The wing design constraints (extended span of 7.5 ft, a closed span of 3 ft) required a tailorable actuator system with capacity to perform at particular target force and strain metrics cyclically. A low spring index parameter study was conducted to facilitate an accelerated phase of design prototyping. The parameter study featured six SMA coil actuator prototypes made with 0.012” diameter Dynalloy Flexinol® wire of varying spring indexes (C = 2.5–4.9). The coil actuators were manufactured through a CNC winding process, shape set in a furnace at 450 °C for 10 minutes, and water quenched for hardening. A series of thermomechanical actuation tests were conducted to experimentally characterize the low spring index actuation performances. The coil actuation characterizations demonstrated increased force and decreased actuator displacement corresponding to decreased spring indexes. Scaling these results aided an accelerated design of an actuator system. The actuator system consisted of four C = 3.05 coil actuators wound with 0.02” diameter SMA that were integrated into each Watt I mechanism. The characterization of the force-displacement profiles for low index SMA coil actuators provides an effective empirical design strategy for scaling actuator performance to mechanical systems requiring moderate force, moderate displacement actuators.

scholarly journals The β-ray spectrum of Ra E

1939 ◽  
Vol 170 (941) ◽  
pp. 190-205 ◽  
Keyword(s):  
Distribution Curve ◽  
High Energy ◽  
Energy Limit ◽  
Total Change ◽  
High Energy Limit ◽  
Nuclear Collisions ◽  
The Past ◽  
Low Energy Electrons ◽  
Energy Distribution Curve ◽  
Chamber Measurements

Interest in the continuous β-ray spectrum has been revived during the past few years by the discovery of induced β-ray activity and the difficulty which has been experienced in incorporating an account of the phenomenon in the theory of the nucleus. Attention has been focused on two features of the spectrum: the high-energy limit, the accurate measurement of which yields the total change in nuclear energy associated with the β disintegration, and the form of the energy distribution curve, which is discriminative in theories of the β-ray emission process. Owing to the convenience of R aE as a source, the β-ray spectrum of this element has received considerable attention, and a comprehensive table of previous work published in a recent paper by O’Conor (1937) shows that recent values of the high-energy limit obtained with magnetic spectrometers are in fair agreement. The form of the R aE spectrum, however, is still not known with any certainty. This can be made clear with the help of Table I, which sets out the results and significant experimental details of the work carried out since 1935 with magnetic spectrometers. Some recent work with cloud expansion chambers is not included because the results are rather discordant. With the relatively low energy electrons of R aE and the high probability of nuclear collisions in the chamber, measurements of the energies of the β-particles are extremely difficult, and the results are probably not as reliable as those obtained with magnetic spectrometers.

scholarly journals Symmetric and triangle-shaped variability of blazars

2014 ◽  
Vol 10 (S313) ◽  
pp. 97-98
Author(s):  
Kenji Yoshida
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Low Energy ◽  
Light Curves ◽  
X Ray ◽  
High Energy Electrons ◽  
Flux Variability ◽  
Low Energy Electrons ◽  
Flux Increase ◽  
Rise Phase

AbstractSymmetric and triangle-shaped flux variability in X-ray and gamma-ray light curves is observed from many blazars. We derived the X-ray spectrum changing in time by using a kinetic equation of high energy electrons. Giving linearly changing the injection of low energy electrons into accelerating and emitting region, we obtained the preliminary results that represent the characteristic X-ray variability of the linear flux increase with hardening in the rise phase and the linear decrease with softening in the decay phase.

Deformation of cube-textured aluminum studied using laser-induced photoelectron emission

2007 ◽  
Vol 22 (9) ◽  
pp. 2582-2589 ◽  
Author(s):  
M. Cai ◽  
S.C. Langford ◽  
J.T. Dickinson ◽  
L.E. Levine
Keyword(s):  
Kinetic Energy ◽  
Energy Distribution ◽  
Tensile Deformation ◽  
High Energy ◽  
Field Energy ◽  
Electron Backscattered Diffraction ◽  
Grain Rotation ◽  
High Energy Electrons ◽  
Low Energy Electrons ◽  
Major Surface

The evolution of the kinetic energy distribution of photoelectrons from a cube-oriented aluminum sample during tensile deformation was probed with a retarding field energy analyzer. Because of the anisotropy of the aluminum work function, the electron-energy distribution is altered as the area fractions of the major surface planes change during deformation. In cube-textured aluminum, deformation reduces the {100} area fraction and the relatively low energy electrons from these surfaces. Conversely, the {110} and {111} area fractions and the relatively high energy electrons from these surfaces both increase. These changes are quantitatively consistent with texture analysis by electron backscattered diffraction (EBSD). They reflect deformation-induced production of {111} surfaces by slip and the exposure of {110} surfaces by grain rotation. Photoelectron kinetic energy measurements supplement EBSD measurements and are readily acquired in real-time.

Sign in / Sign up

Export Citation Format

Share Document