895 research outputs found
The Design and Qualification of a Hydraulic Hardware-in-the-Loop Simulator
The goal of this work was to design and evaluate a hydraulic Hardware-in-the-Loop (HIL) simulation system based around electric and hydraulic motors. The idea behind HIL simulation is to install real hardware within a physically emulated environment, so that genuine performance can be assessed without the expense of final assembly testing. In this case, coupled electric and hydraulic motors were used to create the physical environment emulation by imparting flows and pressures on test hardware. Typically, servo-valves are used for this type of hydraulic emulation, and one of the main purposes of this work was to compare the effectiveness of using motors instead of the somewhat standard servo-valve. Towards this end, a case study involving a Sauer Danfoss proportional valve and emulation of a John Deere backhoe cylinder was undertaken. The design of speed and pressure controllers used in this emulation is presented, and results are compared to data from a real John Deere backhoe and proportional valve. While motors have a substantially lower bandwidth than servo-valves due to their inertia, they have the ability to control pressure at zero and near-zero flows, which is fundamentally impossible for valves. The limitations and unique capabilities of motors are discussed with respect to characteristics of real hydraulic systems.M.S.Committee Chair: Wayne Book; Committee Member: [email protected]; Committee Member: [email protected]
p38 MAPK and the C2C12 cell cycle : in vitro and in silico investigations.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.The mammalian cell cycle and its points-of-entry are well characterized pathways.
These points-of-entry are normally regulated via mitogens and include, amongst others,
the ERK, JNK and p38 mitogen-activated protein kinase (MAPK) pathways. However,
while the restriction point(R-point), the temporal switch-point at which a cell becomes
irrevocably committed to division irrespective of mitogenic stimulus, is known among other
cell types, its position within the murine myoblast line C2C12 is currently unknown.
Similarly, while MAPK pathways, such as JNK and ERK, have been modeled
computationally, no model yet exists of p38 MAPK as stimulated by mitogens. The aims of
this dissertation, then, were to determine the R-point within the C2C12 cell cycle and
construct a computational mitogen-stimulated p38 MAPK model.
It was found that a synchronous C2C12 population, when stimulated to divide, took 7 to
9 hours to reach S-phase from G0, consistent with data from the literature. The R-point
was determined to lie between 6 and 7 hours post G1-re-entry stimulation,which was
consistent with studies in other cell types. Core modeling of the p38 MAPK pathway
revealed that ultrasensitivitywas inherent within the pathway structure. Further, a
branching/re-converging structure within the pathway imparted greater responsiveness to
signal upon the pathway. A realistic p38 MAPK model demonstrated good responsiveness
to signal, its output matched that of several other MAPK models, and it was capable of
replicating previous in vitro data. This model can be used as a tool for further investigation
of the mammalian cell cycle by linking it to other cell cycle models. The predictions by an
expanded model may be better suited for understanding the effects of mitogen stimulus on
the cell cycle in situ
Influence of Ionizing Radiation on the Mechanical Properties of a Wood-Plastic Composite
AbstractThe focus of this study was to examine the potential benefits of irradiating polyethylene (PE)-based wood-plastic composites (WPCs) in order to enhance the mechanical properties of the WPC. The PE-based WPCs were irradiated, post extrusion, at dose levels of 0, 50, 100, 150, 200, and 250 kGy with an electron beam (EB). The irradiated WPCs were then evaluated using a third point bending test (ASTM D4761) along with scanning electron microscopy (SEM). It was found that ultimate strength and modulus of elasticity (MOE) increased with increasing dose level. Examination of the fracture surfaces of polyethylene revealed a distinct difference in failure between irradiated and non-irradiated surfaces
Hypersonic Vehicle Flight Dynamics with Coupled Aerodynamic and Reduced-Order Propulsive Models
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83644/1/AIAA-2010-7930-291.pd
Design Limit Loads and Verification Approach for the TESS Observatory
The Transiting Exoplanet Survey Satellite (TESS) is a NASA Explorer mission. The TESS Observatory is scheduled to launch on Falcon 9 in April 2018. This presentation covers the process used to define and update design limit loads for the observatory, instrument, and components throughout the life of the program. The limit loads that drove the need for a SoftRide isolation system are highlighted. The testing performed to qualify the observatory for launch loads at the instrument and observatory level is also detailed. In addition, exchanges with the launch vehicle provider in terms of loads predictions and hardware for test are discussed along with the associated issues encountered and lessons learned. The loads development and verification success on TESS was a team effort. Orbital ATK is the spacecraft provider, NASA GSFC provides project management and technical oversight, the instrument is managed by MIT Kavli Institute and the instrument cameras are built and tested by MIT Lincoln Laboratory. Since the instrument was designed in parallel with the spacecraft, the instrument design limit loads were developed in partnership with NASA and the instrument team. The three teams collaborated on a regular basis starting in the early design phase and continuing through observatory level testing
Anatomy and growth of a Holocene clinothem in the Gulf of Papua
High-resolution seismic profiles and sedimentological data from grab samples and long cores provide an unprecedented picture of the structure, sedimentology, and late Quaternary development of two Gulf of Papua ( GoP) clinothems, one probably Stage 3 and 4 in age and one Holocene in age. The older was partially eroded during Stage 2 and partially covered by the younger clinothem during Stage 1. The younger clinothem consists of three stratigraphic units separated by two surfaces of erosion, bypass, or correlative surfaces of lap. The surfaces were formed by changes in accommodation and sediment supply. The underlying physiography of the older clinothem also appears to play an important role in governing the shape of the younger clinothem. In the northern gulf, oblique clinoforms of the younger clinothem suggest that the rate of sediment supply from the northern rivers outstripped the formation of new accommodation, whereas in the south, sigmoidal clinoforms indicate that accommodation increased faster than sediment supply. The origin of the new accommodation remains uncertain because of limited age constraints. On the basis of sediment thickness, stratal geometry, and acoustic character, off-shelf transport appears to be the dominant sediment transport direction, with preferential accumulation on the promontories and bypass in the valleys. Presently, observed and computed modern flows and complex gyres in shallow water coupled with wave- and current-supported gravity flows or river floods can explain the form, internal clinoform shapes, and mineralogy of the younger Gulf of Papua clinothem
Creating a Legal Framework for Copyright Management of Open Access within the Australian Academic and Research Sector
There is an increasing recognition, in Australia and internationally, that access to knowledge is a key driver of social, cultural and economic development. The argument for greater access to, and reuse of, research outputs is reinforced by the fact that much research in Australia is funded by public money and, consequently, that there is a public benefit to be served by allowing citizens to access the outputs they have funded.2 This recognition poses both legal and policy challenges, in terms of existing legal frameworks such as copyright law and traditional business models. With the rise of networked digital technologies our knowledge landscape and innovation system is becoming more and more reliant on best practice copyright management strategies and there is a need to accommodate both the demands for open sharing of knowledge and traditional commercialisation models. As a result, new business models that support and promote open innovation are rapidly emerging. This chapter analyses the copyright law framework needed to ensure open access to outputs of the Australian academic and research sector such as journal articles and theses. It overviews the new knowledge landscape, the principles of copyright law, the concept of open access to knowledge, the recently developed open content models of copyright licensing and the challenges faced in providing greater access to knowledge and research outputs
Measuring ‘self’: preliminary validation of a short form of the self experiences questionnaire in people with chronic pain
Background: People with chronic pain often struggle with their sense of self and this can adversely impact their functioning and wellbeing. Acceptance and Commitment Therapy particularly includes a process related to this struggle with self. A measure for this process, the Self Experiences Questionnaire, was previously developed in people with chronic pain.
Purpose: The aim of the current study was to validate a shorter version of the Self Experiences Questionnaire in people with chronic pain to reduce respondent burden and facilitate further research.
Methods: Data from 477 participants attending an interdisciplinary pain management programme were included. Participants completed measures of treatment processes (self-as-context, pain acceptance, cognitive fusion, and committed action) and outcomes (pain, pain interference, work and social adjustment, and depression) at baseline and post-treatment. Confirmatory factor analysis was used for item reduction. Correlations between scores from the shorter Self Experiences Questionnaire and other process and outcome variables were calculated to examine validity. Change scores of the shorter Self Experiences Questionnaire and their correlations with changes in outcome variables were examined for responsiveness.
Results: An eight-item SEQ (SEQ-8) scale including two factors, namely Self-as-Distinction and Self-as-Observer, emerged, demonstrating good reliability (Cronbach’s α=.87-.90) and validity (|r|=.14-.52). Scores from SEQ-8 significantly improved after the treatment (d=.15-21), and these improvements correlated with improvements in most outcomes.
Conclusions: The SEQ-8 appears to be a reliable and valid measure of self. This shorter format may facilitate intensive longitudinal investigation into sense of self and functioning and wellbeing
Specimen collection for the diagnosis of pediatric pneumonia.
Diagnosing the etiologic agent of pneumonia has an essential role in ensuring the most appropriate and effective therapy for individual patients and is critical to guiding the development of treatment and prevention strategies. However, establishing the etiology of pneumonia remains challenging because of the relative inaccessibility of the infected tissue and the difficulty in obtaining samples without contamination by upper respiratory tract secretions. Here, we review the published and unpublished literature on various specimens available for the diagnosis of pediatric pneumonia. We discuss the advantages and limitations of each specimen, and discuss the rationale for the specimens to be collected for the Pneumonia Etiology Research for Child Health study
Petrogenesis of diachronous mixed siliciclastic-carbonate megafacies in the cool-water Oligocene Tikorangi Formation, Taranaki Basin, New Zealand
The Oligocene (Whaingaroan-Waitakian) Tikorangi Formation is a totally subsurface, lithostratigraphically complex, mixed siliciclastic-limestone-rich sequence forming an important fracture reservoir within Taranaki Basin, New Zealand. Petrographically the formation comprises a spectrum of interbedded rock types ranging from calcareous mudstone to wackestone to packstone to clean sparry grainstone. Skeletal and textural varieties within these rock types have aided in the identification of three environmentally distinctive megafacies for the Tikorangi Formation rocks-shelfal, foredeep, and basinal. Data from these megafacies have been used to detail previous conclusions on the petrogenesis and to further refine depositional paleoenvironmental models for the Tikorangi Formation in the central eastern Taranaki Basin margin.Shelfal Megafacies 1 rocks (reference well Hu Road-1A) are latest Oligocene (early Waitakian) in age and formed on or proximal to the Patea-Tongaporutu-Herangi basement high. They are characterised by coarse, skeletal-rich, pure sparry grainstone comprising shallow water, high energy taxa (bryozoans, barnacles, red algae) and admixtures of coarse well-rounded lithic sand derived from Mesozoic basement greywacke. This facies type has previously gone unrecorded in the Tikorangi Formation. Megafacies 2 is a latest Oligocene (early Waitakian) foredeep megafacies (formerly named shelfal facies) formed immediately basinward and west of the shelfal basement platform. It accumulated relatively rapidly (>20 cm/ka) from redeposition of shelfal megafacies biota that became intermixed with bathyal taxa to produce a spectrum of typically mudstone through to sparry grainstone. The resulting skeletal mix (bivalve, echinoderm, planktic and benthic foraminiferal, red algal, bryozoan, nannofossil) is unlike that in any of the age-equivalent limestone units in neighbouring onland King Country Basin. Megafacies 3 is an Oligocene (Whaingaroan-Waitakian) offshore basinal megafacies (formerly termed bathyal facies) of planktic foraminiferal-nannofossil-siliciclastic wackestone and mudstone formed away from redepositional influences. The siliciclastic input in this distal basinal setting (sedimentation rates <7 mm/ka) was probably sourced mainly from oceanic currents carrying suspended sediment from South Island provenances exposed at this time.Tikorangi Formation rocks record the Taranaki Basin’s only period of carbonate-dominated sedimentation across a full range of shelfal, foredeep, and basinal settings. Depositional controls on the three contrasting megafacies were fundamentally the interplay of an evolving and complex plate tectonic setting, including development of a carbonate foredeep, changes in relative sea level within an overall transgressive regime, and changing availability, sources, and modes of deposition of both bioclastic and siliciclastic sediments. The mixed siliciclastic-carbonate nature of the formation, and its skeletal assemblages, low-Mg calcite mineralogy, and delayed deep burial diagenetic history, are features consistent with formation in temperate-latitude cool waters
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