Prediction of struvite formation potential in Ebpr digested sludge using mass balances, batch precipitation tests, and chemical equilibrium modeling

Digested sludge liquors from wastewater treatment plants that include enhanced biological phosphorus removal (EBPR) in their treatment process have the potential to form struvite (MgNH4PO4·6H 2O). The potential can be determined by the concentrations of struvite constituents including phosphorus, ammonium, and magnesium. Phosphorus concentration of digested sludge liquors is expected to increase when EBPR is introduced to wastewater treatment plants because phosphorus accumulating organisms (PAOs) can accumulate phosphorus beyond their metabolic needs and phosphosphorus can be relased when they are digested anaerobically. The work presented in this thesis focuses on determining the potential for struvite formation at the City of Las Vegas Water Pollutant Control Facility (WPCF) due to the introduction of EBPR. Specifically, the struvite formation potential of digested sludge centrate is investigated using mass balances, batch tests, and chemical equilibrium modeling with the software MINEQL+

Philosophical Analysis of the Name of the Discipline ‘Physical Education’ and Proposal of Alternative Terminology

OBJECTIVES The primary objective of this study is to clarify the concepts of physical education and sport from a philosophical perspective and propose the potential of kinesiology as a promising alternative. METHODS The method of philosophical argumentation was employed to carefully examine the logical consistency of physical education, sport, and kinesiology. The conceptual tools of connotation and denotation were used to analyze these definitions, and their compatibility was thoroughly assessed. RESULTS Through deductive analysis, it was discovered that both physical education and sport face inherent challenges of limited externalization and excessive externalization. These challenges hinder the accurate representation of reality or weaken the distinct identity of the disciplines. Conversely, it was argued that kinesiology possesses the conceptual capacity to encompass both physical education and sport as a discipline. CONCLUSIONS Considering the apparent conceptual constraints of physical education, it becomes reasonable to reassess the nomenclature of our field. This paper has demonstrated the philosophical significance of kinesiology and its potential as a viable alternative. However, since philosophical arguments may not always perfectly align with practical reality, further exploration and evaluation from diverse perspectives are necessary to determine the suitability of adopting the term ‘kinesiology’ as an alternative

Use of impact fees to incentivize low-impact development and promote compact growth

Low-impact development (LID) is an innovative stormwater management strategy that restores the predevelopment hydrology to prevent increased stormwater runoff from land development. Integrating LID into residential subdivisions and increasing population density by building more compact living spaces (e.g., apartment homes) can result in a more sustainable city by reducing stormwater runoff, saving infrastructural cost, increasing the number of affordable homes, and supporting public transportation. We develop an agent-based model (ABM) that describes the interactions between several decision-makers (i.e., local government, a developer, and homebuyers) and fiscal drivers (e.g., property taxes, impact fees). The model simulates the development of nine square miles of greenfield land. A more sustainable development (MSD) scenario introduces an impact fee that developers must pay if they choose not to use LID to build houses or apartment homes. Model simulations show homeowners selecting apartment homes 60% or 35% of the time after 30 years of development in MSD or business as usual (BAU) scenarios, respectively. The increased adoption of apartment homes results from the lower cost of using LID and improved quality of life for apartment homes relative to single-family homes. The MSD scenario generates more tax revenue and water savings than does BAU. A time-dependent global sensitivity analysis quantifies the importance of socioeconomic variables on the adoption rate of apartment homes. The top influential factors are the annual pay rates (or capital recovery factor) for single-family houses and apartment homes. The ABM can be used by city managers and policymakers for scenario exploration in accordance with local conditions to evaluate the effectiveness of impact fees and other policies in promoting LID and compact growth

Carbon nanotube diode fabricated by contact engineering with self-assembled molecules

The authors report the construction of carbon nanotube Schottky diodes by covering a selectively exposed area of the electrode with self-assembling molecules. Two self-assembling molecules with different polarities, 2-aminoethanethiol and 3-mercaptopropionic acid, were used to modify the Fermi level lineup at the selected contact. The devices showed p -type behavior with symmetric I-V showing clear rectifying behavior after treatment of one contact with 2-aminoethanethiol. Their experiment, in conjunction with the results of ab initio electronic structure calculations, suggests that the diode action stems from the asymmetric Fermi level lineup between the bare and engineered contacts.open131

The MHD Kelvin-Helmholtz Instability III: The Role of Sheared Magnetic Field in Planar Flows

We have carried out simulations of the nonlinear evolution of the magnetohydrodynamic (MHD) Kelvin-Helmholtz (KH) instability for compressible fluids in $2\frac{1}{2}$-dimensions, extending our previous work by Frank et al (1996) and Jones \etal (1997). In the present work we have simulated flows in the x-y plane in which a ``sheared'' magnetic field of uniform strength ``smoothly'' rotates across a thin velocity shear layer from the z direction to the x direction, aligned with the flow field. We focus on dynamical evolution of fluid features, kinetic energy dissipation, and mixing of the fluid between the two layers, considering their dependence on magnetic field strength for this geometry. The introduction of magnetic shear can allow a Cat's Eye-like vortex to form, even when the field is stronger than the nominal linear instability limit given above. For strong fields that vortex is asymmetric with respect to the preliminary shear layer, however, so the subsequent dissipation is enhanced over the uniform field cases of comparable field strength. In fact, so long as the magnetic field achieves some level of dynamical importance during an eddy turnover time, the asymmetries introduced through the magnetic shear will increase flow complexity, and, with that, dissipation and mixing. The degree of the fluid mixing between the two layers is strongly influenced by the magnetic field strength. Mixing of the fluid is most effective when the vortex is disrupted by magnetic tension during transient reconnection, through local chaotic behavior that follows.Comment: 14 pages including 9 figures (4 figures in degraded jpg format), full paper with original quality figures available via anonymous ftp at ftp://canopus.chungnam.ac.kr/ryu/mhdkh2d.uu, to appear in The Astrophysical Journa

Precessing Jet and Large Dust Grains in the V380 Ori NE Star-forming Region

The V380 Ori NE bipolar outflow was imaged in the SiO and CO J = 1 - 0 lines, and dense cores in L1641 were observed in the 2.0-0.89 mm continuum. The highly collimated SiO jet shows point-symmetric oscillation patterns in both position and velocity, which suggests that the jet axis is precessing and the driving source may belong to a non-coplanar binary system. By considering the position and velocity variabilities together, accurate jet parameters were derived. The protostellar system is viewed nearly edge-on, and the jet has a flow speed of 35 km/s and a precession period of 1600 years. The CO outflow length gives a dynamical timescale of 6300 years, and the protostar must be extremely young. The inferred binary separation of 6-70 au implies that this protobinary system may have been formed through the disk instability process. The continuum spectra of L1641 dense cores indicate that the emission comes from dust, and the fits with modified blackbody functions give emissivity power indices of beta = 0.3-2.2. The emissivity index shows a positive correlation with the molecular line width, but no strong correlation with bolometric luminosity or temperature. V380 Ori NE has a particularly low value of beta = 0.3, which tentatively suggests the presence of millimeter-sized dust grains. Because the dust growth takes millions of years, much longer than the protostellar age, this core may have produced large grains in the starless core stage. HH 34 MMS and HH 147 MMS also have low emissivity indices.Comment: To appear in the Astrophysical Journal Supplement Serie

Air-stable n-type operation of Gd-contacted carbon nanotube field effect transistors

We report air-stable n -type operations of the single-walled carbon nanotube field effect transistors (SWNT-FETs) fabricated with Gd electrodes. Unlike previously reported n -type SWNT-FETs, our devices maintained their n -type operation characteristics in ambient atmosphere for more than two months. The shallow Gd films with a thickness below 20 nm are corroded by environmental oxygen, whereas the well-contacted Gd-SWNT interfaces underneath the thick Gd layers are protected from contaminations by air molecules. Theoretical studies based on the first-principles electronic structure calculations confirm that Gd layers have an excellent binding affinity to the SWNTs.open8