INFLUENCE OF LOCALLY PRODUCED WOOD BIOCHAR ON SOIL NITROGEN AND PHOSPHORUS DYNAMICS IN THE NORTHWESTERN US

Wildfire cause a rapid and sometimes dramatic loss of carbon and nitrogen from forest ecosystems, but it also leaves behind ash and charcoal on the soil surface, both of which affect soil properties, processes, and function. Some of these effects may be induced by applying charcoal or biochar to surface soils. Biochar is the term given to the carbon rich product of thermochemical decomposition of organic material in an oxygen limited environment that is explicitly intended for soil application. Producing biochar from wood residues from timber harvest and applying it to nearby soils may represent a means of reducing carbon emissions associated with wood residue management while providing an innovative approach to potentially improve soil fertility and plant productivity. To date, few biochar studies have been conducted as a part of a holistic closed loop system across ecosystems. The purpose of this dissertation was therefore to improve our understanding of how locally produced wood biochar influences soil nitrogen (N) and phosphorus (P) dynamics in organic agriculture, temperate forest, and semi-natural rangeland ecosystems in the Northwestern US. Several key findings from the experiments conducted at sites in WA and MT include: (1) Applying wood biochar alone on a relatively fertile agricultural soil generally had a neutral effect on soil N turnover, but by contrast, biochar increased soil nitrification and N mobility in a natural, organic rich rangeland ecosystem; (2) Combining wood biochar with an organic fertilizer created positive synergistic effects on soil N cycling rates and availability while reducing N leaching potential; (3) Soil P bioavailability was generally increased by wood biochar application regardless of ecosystem type or the combined use of fertilizer. This result appeared to be primarily a function of biochar characteristics and potentially associated with abiotic P mobilization processes rather than biotic mechanisms; (4) Slight acidic soils benefit from wood biochar the most at their multi-functionality in N or P cycling compared to pH neutral or alkaline soils; (5) Wood biochar immediately accelerated solution N flux rates in the charosphere of temperate mixed-forest soil that features a sandy loam texture and neutral pH, a result highlighting the uncertainty in, and the dynamism of, the responses of nutrient pools and fluxes to biochar additions across different scales; and (6) Wood biochar did not impart any negative impacts on soil processes examined in these studies. Overall, this work provides an important contribution to our collective knowledge of the value and function of locally produced wood biochar as a bio-enhancing soil amendment for ecosystem nutrient management in the Northwestern US

g-B3N3C: a novel two-dimensional graphite-like material

A novel crystalline structure of hybrid monolayer hexagonal boron nitride (BN) and graphene is predicted by means of the first-principles calculations. This material can be derived via boron or nitrogen atoms substituted by carbon atoms evenly in the graphitic BN with vacancies. The corresponding structure is constructed from a BN hexagonal ring linking an additional carbon atom. The unit cell is composed of 7 atoms, 3 of which are boron atoms, 3 are nitrogen atoms, and one is carbon atom. It behaves a similar space structure as graphene, which is thus coined as g-B3N3C. Two stable topological types associated with the carbon bonds formation, i.e., C-N or C-B bonds, are identified. Interestingly, distinct ground states of each type, depending on C-N or C-B bonds, and electronic band gap as well as magnetic properties within this material have been studied systematically. Our work demonstrates practical and efficient access to electronic properties of two-dimensional nanostructures providing an approach to tackling open fundamental questions in bandgap-engineered devices and spintronics.Comment: 15 pages, 6 figure

Locating the Gribov horizon

We explore whether a tree-level expression for the gluon two-point function, supposed to express effects of an horizon term introduced to eliminate the Gribov ambiguity, is consistent with the propagator obtained in simulations of lattice-regularised quantum chromodynamics (QCD). In doing so, we insist that the gluon two-point function obey constraints that ensure a minimal level of consistency with parton-like behaviour at ultraviolet momenta. In consequence, we are led to a position which supports a conjecture that the gluon mass and horizon scale are equivalent emergent mass-scales, each with a value of roughly $0.5\,$GeV; and wherefrom it appears plausible that the dynamical generation of a running gluon mass may alone be sufficient to remove the Gribov ambiguity.Comment: 7 pages, 2 figures, 2 table

Graphics processing unit accelerating compressed sensing photoacoustic computed tomography with total variation

Photoacoustic computed tomography with compressed sensing (CS-PACT) is a commonly used imaging strategy for sparse-sampling PACT. However, it is very time-consuming because of the iterative process involved in the image reconstruction. In this paper, we present a graphics processing unit (GPU)-based parallel computation framework for total-variation-based CS-PACT and adapted into a custom-made PACT system. Specifically, five compute-intensive operators are extracted from the iteration algorithm and are redesigned for parallel performance on a GPU. We achieved an image reconstruction speed 24–31 times faster than the CPU performance. We performed in vivo experiments on human hands to verify the feasibility of our developed method

Zero mode in a strongly coupled quark gluon plasma

In connection with massless two-flavour QCD, we analyse the chiral symmetry restoring phase transition using three distinct gluon-quark vertices and two different assumptions about the long-range part of the quark-quark interaction. In each case, we solve the gap equation, locate the transition temperature T_c, and use the maximum entropy method to extract the dressed-quark spectral function at T>T_c. Our best estimate for the chiral transition temperature is T_c=(147 +/- 8)MeV; and the deconfinement transition is coincident. For temperatures markedly above T_c, we find a spectral density that is consistent with those produced using a hard thermal loop expansion, exhibiting both a normal and plasmino mode. On a domain T\in[T_c,T_s], with T_s approximately 1.5T_c, however, with each of the six kernels we considered, the spectral function contains a significant additional feature. Namely, it displays a third peak, associated with a zero mode, which is essentially nonperturbative in origin and dominates the spectral function at T=T_c. We suggest that the existence of this mode is a signal for the formation of a strongly-coupled quark-gluon plasma and that this strongly-interacting state of matter is likely a distinctive feature of the QCD phase transition.Comment: 11 pages, 5 figures, 1 tabl

Understanding the viscera-related theory that the lung and large intestine are exterior-interiorly related

AbstractPairing of the viscera and bowels is an important theory, which provides guidance to traditional Chinese medicine (TCM) clinical practice. Investigating this theory has been the focus of research on the basic theory of TCM. Recently, researchers have performed many studies on the theory that the lung and large intestine are exterior-interiorly related, which is a different point of view to that of previous literature, recent clinical studies and experimental studies, and these recent studies have enforced the theoretical connotation of the statement. However, there are problems in some of these studies including recent clinical studies and experimental studies. In the current article, literature on the viscera-related theory of the lung and large intestine are exterior-interiorly related is reviewed from physiological, pathological, and clinical views, and some opinions on the current research status are discussed

Phase diagram and thermal properties of strong-interaction matter

We introduce a novel procedure for computing the (mu,T)-dependent pressure in continuum QCD; and therefrom obtain a complex phase diagram and predictions for thermal properties of the system, providing the in-medium behaviour of the trace anomaly, speed of sound, latent heat and heat capacity.Comment: 6 pages, 4 figures. Minor amendments in the version accepted for publicatio

SU(3) Quantum Interferometry with single-photon input pulses

We develop a framework for solving the action of a three-channel passive optical interferometer on single-photon pulse inputs to each channel using SU(3) group-theoretic methods, which can be readily generalized to higher-order photon-coincidence experiments. We show that features of the coincidence plots vs relative time delays of photons yield information about permanents, immanants, and determinants of the interferometer SU(3) matrix