1,040 research outputs found
Piles and pile driving
This thesis on the subject of Piles and Pile Driving has been written to fulfill one of the requirements for the granting of the degree of Civil Engineer by the Newark College of Engineering. The material contained in this thesis has been gleaned from many books, catalogs, magazines and from the author\u27s own experience. Much still needs to be accomplished in the field of research but this can be done only through the cooperation of the companies who are engaged in this work and have the equipment necessary for making many tests under actual field conditions.
The author wishes to acknowledge his indebtedness to the following companies for the information which they have supplied and also for the illustrations, some of which are reproduced in this thesis: - Russell Company, Charles R. Gow Company, Mac Arthur Concrete Pile Corporation, The Raymond Concrete Pile Company, and The Southern Wood Preserving Company. The author is also indebted to Professor William S. La Londe of the Newark College of Engineering for reading the manuscript and making valuable suggestions
Desulfovibrio paquesii sp. nov., a hydrogenotrophic sulfate-reducing bacterium isolated from a synthesis-gas-fed bioreactor treating zinc- and sulfate-rich wastewater
A hydrogenotrophic, sulfate-reducing bacterium, designated strain SB1(T), was isolated from sulfidogenic sludge of a full-scale synthesis-gas-fed bioreactor used to remediate wastewater from a zinc smelter. Strain SB1(T) was found to be an abundant micro-organism in the sludge at the time of isolation. Hydrogen, formate, pyruvate, lactate, malate, fumarate, succinate, ethanol and glycerol served as electron donors for sulfate reduction. Organic substrates were incompletely oxidized to acetate. 16S rRNA gene sequence analysis showed that the closest recognized relative to strain SB1(T) was Desulfovibrio gigas DSM 1382(T) (97.5 % similarity). The G+C content of the genomic DNA of strain SB1(T) was 62.2 mol%, comparable with that of Desulfovibrio gigas DSM 1382(T) (60.2 mol%). However, the level of DNA-DNA relatedness between strain SB1(T) and Desulfovibrio gigas DSM 1382(T) was only 56.0 %, indicating that the two strains are not related at the species level. Strain SB1(T) could also be differentiated from Desulfovibrio gigas based on phenotypic characteristics, such as major cellular fatty acid composition (anteiso-C(15 : 0), iso-C(14 : 0) and C(18 : 1) cis 9) and substrate utilization. Strain SB1(T) is therefore considered to represent a novel species of the genus Desulfovibrio, for which the name Desulfovibrio paquesii sp. nov. is proposed. The type strain is SB1(T) (=DSM 16681(T)=JCM 14635(T)
Extremal transmission at the Dirac point of a photonic band structure
We calculate the effect of a Dirac point (a conical singularity in the band
structure) on the transmission of monochromatic radiation through a photonic
crystal. The transmission as a function of frequency has an extremum at the
Dirac point, depending on the transparencies of the interfaces with free space.
The extremal transmission is inversely proportional to
the longitudinal dimension of the crystal (for larger than the lattice
constant and smaller than the transverse dimension ). The interface
transparencies affect the proportionality constant , and they
determine whether the extremum is a minimum or a maximum, but they do not
affect the ``pseudo-diffusive'' 1/L dependence of .Comment: 6 pages, 4 figures. Fig. 1 revised, Fig. 4 adde
Integer quantum Hall effect on a six valley hydrogen-passivated silicon (111) surface
We report magneto-transport studies of a two-dimensional electron system
formed in an inversion layer at the interface between a hydrogen-passivated
Si(111) surface and vacuum. Measurements in the integer quantum Hall regime
demonstrate the expected sixfold valley degeneracy for these surfaces is
broken, resulting in an unequal occupation of the six valleys and anisotropy in
the resistance. We hypothesize the misorientation of Si surface breaks the
valley states into three unequally spaced pairs, but the observation of odd
filling factors, is difficult to reconcile with non-interacting electron
theory.Comment: 4 pages, 4 figures, to appear in Physical Review Letter
On an inverse problem from magnetic resonance elastic imaging
The imaging problem of elastography is an inverse problem. The nature of an inverse problem is that it is ill-conditioned. We consider properties of the mathematical map which describes how the elastic properties of the tissue being reconstructed vary with the field measured by magnetic resonance imaging (MRI). This map is a nonlinear mapping, and our interest is in proving certain conditioning and regularity results for this operator which occurs implicitly in this problem of imaging in elastography. In this treatment we consider the tissue to be linearly elastic, isotropic, and spatially heterogeneous. We determine the conditioning of this problem of function reconstruction, in particular for the stiffness function. We further examine the conditioning when determining both stiffness and density. We examine the Frechet derivative of the nonlinear mapping, which enables us to describe the properties of how the field affects the individual maps to the stiffness and density functions. We illustrate how use of the implicit function theorem can considerably simplify the analysis of Frechet differentiability and regularity properties of this underlying operator. We present new results which show that the stiffness map is mildly ill-posed, whereas the density map suffers from medium ill-conditioning. Computational work has been done previously to study the sensitivity of these maps, but our work here is analytical. The validity of the Newton-Kantorovich and optimization methods for the computational solution of this inverse problem is directly linked to the Frechet differentiability of the appropriate nonlinear operator, which we justify
Charge transport through weakly open one dimensional quantum wires
We consider resonant transmission through a finite-length quantum wire
connected to leads via finite transparency junctions. The coherent electron
transport is strongly modified by the Coulomb interaction. The low-temperature
current-voltage () curves show step-like dependence on the bias voltage
determined by the distance between the quantum levels inside the conductor, the
pattern being dependent on the ratio between the charging energy and level
spacing. If the system is tuned close to the resonance condition by the gate
voltage, the low-voltage curve is Ohmic. At large Coulomb energy and low
temperatures, the conductance is temperature-independent for any relationship
between temperature, level spacing, and coupling between the wire and the
leads
The Effects of External Motivation and Real-Time Automated Feedback on Speeding Behavior in a Naturalistic Setting
Objective: In this field experiment, the authors tested an alerting system and a monetary incentive system with the objective of reducing speeding more than 5 mph faster than the posted speed limit.
Background: Speeding is a factor in a significant number of traffic fatalities. The systems tested in this project have been evaluated outside but not within the United States. These studies indicated that similar systems led to reductions in speeding.
Method: For this study, eight vehicles were instrumented such that vehicle speed and speed limits were linked in real time. A total of 50 participants drove assigned vehicles for 4 weeks. Week 1 was a baseline period; during Week 2 or Week 3, 40 participants experienced the alerting system that issued auditory and visual advisory signals when drivers exceeded the limit by 5 mph or more. Of these 40 individuals, 20 experienced the monetary incentive system during Weeks 2 and 3; Week 4 was a return-to-baseline period. A control group of 10 drivers experienced neither system during the study.
Results: Results indicated that the incentive system resulted in significant reductions in driving faster than the posted limit, and the feedback system led to modest changes in speeding. In the condition in which drivers experienced the feedback and incentive, reductions in speeding were similar to those found during the incentive-only condition.
Conclusion: The technology tested in this study has potential to benefit traffic safety by reducing the incidence of driving faster than the posted limit, which should lead to a reduction in speed-related crashes.
Application: Insurers provide incentive-based discounts on premiums. Combining this technology with such a discount program may improve traffic safety significantly
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