827 research outputs found
Regional Wastewater Facility Systems Design
The San José-Santa Clara Regional Wastewater Facility (RWF) was constructed in 1956 as a primary water treatment plant. Secondary treatment facilities were constructed in 1964 in response to a growing population and economy along with state regulations. The RWF expanded to tertiary treatment in 1979 to meet Clean Water Act regulations. A wet weather headworks facility was commissioned in 2008, and in 2011 the gaseous chlorine/sulfur dioxide system for disinfection was converted to a sodium hypochlorite/sodium bisulfate system in 2011 (RWF 2015). The RWF launched a Capital Improvement Program (CIP) in 2014, identifying 33 capital projects. The Facility Wide Water Systems package (package PF-06) in the CIP served as the inspiration of the Regional Wastewater Facility Systems Design project.
Package PF-06 states that the RWF has four water systems in need of rehabilitation and upgrade: 1W (potable water), 2W (groundwater), 3W (process water) and 4W (fire protection water). Due to age, condition, and change in water demands over time, the RWF requested an updated hydraulic model and assessment of current and future water demands for a proper redesign of each system. The Hydraulic Engineering and Design (HEAD) team has decided to redesign the RWF’s 1W and 2W systems for this capstone project
Remnants of semiclassical bistability in the few-photon regime of cavity QED
Broadband homodyne detection of the light transmitted by a Fabry-Perot cavity
containing a strongly-coupled Cs atom is used to probe the dynamic
optical response in a regime where semiclassical theory predicts bistability
but strong quantum corrections should apply. While quantum fluctuations
destabilize true equilibrium bistability, our observations confirm the
existence of metastable states with finite lifetimes and a hysteretic response
is apparent when the optical drive is modulated on comparable timescales. Our
experiment elucidates remnant semiclassical behavior in the attojoule (
photon) regime of single-atom cavity QED, of potential significance for
ultra-low power photonic signal processing.Comment: 14 pages, 7 figure
Surface Instability in Windblown Sand
We investigate the formation of ripples on the surface of windblown sand
based on the one-dimensional model of Nishimori and Ouchi [Phys. Rev. Lett. 71,
197 (1993)], which contains the processes of saltation and grain relaxation. We
carry out a nonlinear analysis to determine the propagation speed of the
restabilized ripple patterns, and the amplitudes and phases of their first,
second, and third harmonics. The agreement between the theory and our numerical
simulations is excellent near the onset of instability. We also determine the
Eckhaus boundary, outside which the steady ripple patterns are unstable.Comment: 23 pages, 8 figure
Circumstellar Structure around Evolved Stars in the Cygnus-X Star Formation Region
We present observations of newly discovered 24 micron circumstellar
structures detected with the Multiband Imaging Photometer for Spitzer (MIPS)
around three evolved stars in the Cygnus-X star forming region. One of the
objects, BD+43 3710, has a bipolar nebula, possibly due to an outflow or a
torus of material. A second, HBHA 4202-22, a Wolf-Rayet candidate, shows a
circular shell of 24 micron emission suggestive of either a limb-brightened
shell or disk seen face-on. No diffuse emission was detected around either of
these two objects in the Spitzer 3.6-8 micron Infrared Array Camera (IRAC)
bands. The third object is the luminous blue variable candidate G79.29+0.46. We
resolved the previously known inner ring in all four IRAC bands. The 24 micron
emission from the inner ring extends ~1.2 arcmin beyond the shorter wavelength
emission, well beyond what can be attributed to the difference in resolutions
between MIPS and IRAC. Additionally, we have discovered an outer ring of 24
micron emission, possibly due to an earlier episode of mass loss. For the two
shell stars, we present the results of radiative transfer models, constraining
the stellar and dust shell parameters. The shells are composed of amorphous
carbon grains, plus polycyclic aromatic hydrocarbons in the case of
G79.29+0.46. Both G79.29+0.46 and HBHA 4202-22 lie behind the main Cygnus-X
cloud. Although G79.29+0.46 may simply be on the far side of the cloud, HBHA
4202-22 is unrelated to the Cygnus-X star formation region.Comment: Accepted by A
Defective microtubule-dependent podosome organization in osteoclasts leads to increased bone density in Pyk2−/− mice
The protein tyrosine kinase Pyk2 is highly expressed in osteoclasts, where it is primarily localized in podosomes. Deletion of Pyk2 in mice leads to mild osteopetrosis due to impairment in osteoclast function. Pyk2-null osteoclasts were unable to transform podosome clusters into a podosome belt at the cell periphery; instead of a sealing zone only small actin rings were formed, resulting in impaired bone resorption. Furthermore, in Pyk2-null osteoclasts, Rho activity was enhanced while microtubule acetylation and stability were significantly reduced. Rescue experiments by ectopic expression of wild-type or a variety of Pyk2 mutants in osteoclasts from Pyk2−/− mice have shown that the FAT domain of Pyk2 is essential for podosome belt and sealing zone formation as well as for bone resorption. These experiments underscore an important role of Pyk2 in microtubule-dependent podosome organization, bone resorption, and other osteoclast functions
Overlapping IgG4 Responses to Self- and Environmental Antigens in Endemic Pemphigus Foliaceus
The etiology of human autoimmune diseases in general remains largely unknown, although the genetic and environmental interplay may be relevant. This applies to the autoimmune diseases of the skin such as the pemphigus phenotypes and others. In this group, there is an endemic form of pemphigus foliaceus [also known as Fogo Selvagem (FS)] where the pathogenic IgG4 autoantibody response to the self-antigen, Desmoglein 1 (Dsg1) cross-react with the LJM11 sand fly salivary gland antigen. In this investigation we dissected the IgG4 autoantibody repertoires utilized by FS patients in response to endogenous self Dsg1 and exogenous LJM11 sand fly antigen. Based on analyses of the genetic clonal signatures of these antibodies, our results indicate that there is a significant overlap between these two responses as all identified IgG4 monoclonal antibodies cross-react to both Dsg1 and LJM11 antigens. Germline H and L chain V gene antibodies generated according to mutated cross-reactive monoclonal antibodies preserved their reactivity to both antigens. Our findings suggest that both Dsg1 autoantigen and LJM11 environmental antigen could be the initial antigenic stimulants for the IgG4 autoimmune responses in FS. These results support our hypothesis that LJM11 antigen plays a substantial role in triggering the IgG4 autoantibody development in FS, and provide new insights on how non-infectious environmental antigen(s) may drive the generation of autoantibodies in IgG4-related autoimmune diseases
Higher D or Li: Probes of Physics beyond the Standard Model
Standard Big Bang Nucleosynthesis at the baryon density determined by the
microwave anisotropy spectrum predicts an excess of \li7 compared to
observations by a factor of 4-5. In contrast, BBN predictions for D/H are
somewhat below (but within ~2 \sigma) of the weighted mean of observationally
determined values from quasar absorption systems. Solutions to the \li7 problem
which alter the nuclear processes during or subsequent to BBN, often lead to a
significant increase in the deuterium abundance consistent with the highest
values of D/H seen in absorption systems. Furthermore, the observed D/H
abundances show considerable dispersion. Here, we argue that those systems with
D/H \simeq 4 \times 10^{-5} may be more representative of the primordial
abundance and as a consequence, those systems with lower D/H would necessarily
have been subject to local processes of deuterium destruction. This can be
accounted for by models of cosmic chemical evolution able to destroy in situ
Deuterium due to the fragility of this isotope.Comment: 22 pages, 8 figure
Microscopic Origins of Electron and Hole Stability in ZnO
A novel and direct method is proposed to assess the doping limits of
semiconducting materials. Applied to the case of ZnO, our first-principles
calculations demonstrate that p-type ZnO is thermodynamically unstable.Comment: Accepted to Chemical Communications (2011
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