4,079 research outputs found
Micro-abrasion-corrosion interactions of Ni-Cr/WC based coatings : approaches to construction of tribo-corrosion maps for the abrasion-corrosion synergism
The process of micro-abrasion-corrosion has been the subject of much research in recent years due to the fact that the action of micron sized particles, typically less than 10 um in diameter, can cause significant degradation of materials in many diverse environments involving aqueous corrosion. Cermet based coatings are often used to combat micro-abrasion-corrosion, but has been little work carried out to characterize the performance of such coatings exposed to micro-abrasion-corrosion or to provide a basis for coating optimisation. In addition, a basis for defining the various micro-abrasion-corrosion interactions has not been suggested to date. In this study the micro-abrasion-corrosion performance of a Ni-Cr/WC coating was assessed and compared to the performance of the steel substrate. The results were used to identify regimes of micro-abrasion as a function of applied load and pH of the solution. In addition, micro-abrasion-corrosion maps were constructed based on the results, showing the variation between micro-abrasion-corrosion regimes, as a function of applied load and pH of the solution
GEMPAK: An arbitrary aircraft geometry generator
A computer program, GEMPAK, has been developed to aid in the generation of detailed configuration geometry. The program was written to allow the user as much flexibility as possible in his choices of configurations and the detail of description desired and at the same time keep input requirements and program turnaround and cost to a minimum. The program consists of routines that generate fuselage and planar-surface (winglike) geometry and a routine that will determine the true intersection of all components with the fuselage. This paper describes the methods by which the various geometries are generated and provides input description with sample input and output. Also included are descriptions of the primary program variables and functions performed by the various routines. The FORTRAN program GEMPAK has been used extensively in conjunction with interfaces to several aerodynamic and plotting computer programs and has proven to be an effective aid in the preliminary design phase of aircraft configurations
The Oyster River Culvert Analysis Project
Studies have already detected intensification of precipitation events consistent with climate change projections. Communities may have a window of opportunity to prepare, but information sufficiently quantified and localized to support adaptation programs is sparse: published literature is typically characterized by general resilience building or regional vulnerability studies. The Fourth Assessment Report of the IPCC observed that adaptation can no longer be postponed pending the effective elimination of uncertainty. Methods must be developed that manage residual uncertainty, providing community leaders with decision-support information sufficient for implementing infrastructure adaptation programs. This study developed a local-scale and actionable protocol for maintaining historical risk levels for communities facing significant impacts from climate change and population growth. For a coastal watershed, the study assessed the capacity of the present stormwater infrastructure capacity for conveying expected peak flow resulting from climate change and population growth. The project transferred coupled-climate model projections to the culvert system, in a form understandable to planners, resource managers and decision-makers; applied standard civil engineering methods to reverse-engineer culverts to determine existing and required capacities; modeled the potential for LID methods to manage peak flow in lieu of, or combination with, drainage system upsizing; and estimated replacement costs using local and national construction cost data. The mid-21st century, most likely 25-year, 24-hour precipitation is estimated to be 35% greater than the TP-40 precipitation for the SRES A1b trajectory, and 64% greater than the TP-40 value for the SRES A1fi trajectory. 5% of culverts are already undersized for the TP-40 event to which they should have been designed. Under the most likely A1b trajectory, an additional 12% of culverts likely will be undersized, while under the most likely A1fi scenario, an additional 19% likely will be undersized. These conditions place people and property at greater risk than that historically acceptable from the TP-4025-year design storm. This risk level may be maintained by a long-term upgrade program, utilizing existing strategies to manage uncertainty and costs. At the upper-95% confidence limit for the A1fi 25-year event, 65% of culverts are adequately sized, and building the remaining 35%, and planned, culverts to thrice the cross-sectional area specified from TP-40 should provide adequate capacity through this event. Realizable LID methods can mitigate significant impacts from climate change and population growth, however effectiveness is limited for the more pessimistic climate change projections. Results indicate that uncertainty in coupled-climate model projections is not an impediment to adaptation. This study makes a significant contribution toward the generation of reliable and specific estimates of impacts from climate change, in support of programs to adapt civil infrastructures. This study promotes a solution to today\u27s arguably most significant challenge in civil infrastructure adaptation: translating the extensive corpus of adaptation theory and regional-scale impacts analyses into localscale action
Design and experimental evaluation of a swept supercritical Laminar Flow Control (LFC) airfoil
A large chord swept supercritical laminar flow control (LFC) airfoil was designed, constructed, and tested in the NASA Langley 8-ft Transonic Pressure Tunnel (TPT). The LFC airfoil experiment was established to provide basic information concerning the design and compatibility of high-performance supercritical airfoils with suction boundary layer control achieved through discrete fine slots or porous surface concepts. It was aimed at validating prediction techniques and establishing a technology base for future transport designs and drag reduction. Good agreement was obtained between measured and theoretically designed shockless pressure distributions. Suction laminarization was maintained over an extensive supercritical zone up to high Reynolds numbers before transition gradually moved forward. Full-chord laminar flow was maintained on the upper and lower surfaces at M sub infinity = 0.82 up to R sub c is less than or equal to 12 x 10 to the 6th power. When accounting for both the suction and wake drag, the total drag could be reducted by at least one-half of that for an equivalent turbulent airfoil. Specific objectives for the LFC experiment are given
A feasibility study of signed consent for the collection of patient identifiable information for a national paediatric clinical audit database
Objectives: To investigate the feasibility of obtaining signed consent
for submission of patient identifiable data to a national clinical
audit database and to identify factors influencing the consent process
and its success.
Design: Feasibility study.
Setting: Seven paediatric intensive care units in England.
Participants: Parents/guardians of patients, or patients aged 12-16
years old, approached consecutively over three months for signed
consent for submission of patient identifiable data to the national
clinical audit database the Paediatric Intensive Care Audit Network
(PICANet).
Main outcome measures: The numbers and proportions of admissions for
which signed consent was given, refused, or not obtained (form not
returned or form partially completed but not signed), by age, sex,
level of deprivation, ethnicity (South Asian or not), paediatric index
of mortality score, length of hospital stay (days in paediatric
intensive care).
Results: One unit did not start and one did not fully implement the
protocol, so analysis excluded these two units. Consent was obtained
for 182 of 422 admissions (43%) (range by unit 9% to 84%). Most
(101/182; 55%) consents were taken by staff nurses. One refusal (0.2%)
was received. Consent rates were significantly better for children who
were more severely ill on admission and for hospital stays of six days
or more, and significantly poorer for children aged 10-14 years. Long
hospital stays and children aged 10-14 years remained significant in a
stepwise regression model of the factors that were significant in the
univariate model.
Conclusion: Systematically obtaining individual signed consent for
sharing patient identifiable information with an externally located
clinical audit database is difficult. Obtaining such consent is
unlikely to be successful unless additional resources are specifically
allocated to training, staff time, and administrative support
Wall-temperature effects on the aerodynamics of a hydrogen-fueled transport concept in Mach 8 blowdown and shock tunnels
Results are presented from two separate tests on the same blended wing-body hydrogen fueled transport model at a Mach number of about 8 and a range of Reynolds numbers (based on theoretical body length) of 0.597 x 10 to the 6th power to about 156.22 x 10 to the 6th power. Tests were made in conventional hypersonic blowdown tunnel and a hypersonic shock tunnel at angles of attack of -2 deg to about 8 deg, with an extensive study made at a constant angle of attack of 3 deg. The model boundary-layer flow varied from laminar at the lower Reynolds numbers to predominantly turbulent at the higher Reynolds numbers. Model wall temperatures and stream static temperatures varied widely between the two tests, particularly at the lower Reynolds numbers. These temperature differences resulted in marked variations of the axial-force coefficients between the two tests, due in part to the effects of induced pressure and viscous interaction variations. The normal-force coefficient was essentially independent of Reynolds number. Analysis of results utilized current theoretical computer programs and basic boundary-layer theory
UK-South Asian patients' experiences of and satisfaction toward receiving information about biologics in rheumatoid arthritis
Background: Rheumatoid arthritis (RA) causes painful joint inflammation and is incurable, but treatments control RA. Drug regimens are complex, and patients often do not take their medication as expected. Poor medication adherence can lead to poorly controlled disease and worse patient outcomes. Biologics treatments are expensive and require full engagement from patients. We have previously shown that patients from Black ethnic minority backgrounds do not fully engage into treatment plan. This study explored the patients’ experiences in and satisfaction toward receiving information about biologics and future support preferences in South Asian patients with RA.
Methods: Twenty South Asian patients with RA from Royal Wolverhampton Hospitals NHS Trust and Central Manchester University Hospitals NHS Foundation Trust participated in individual semi-structured interviews. Interviews were transcribed and data were analyzed by using thematic analysis approach.
Results: Four overarching themes describe the patients’ experience in and satisfaction toward receiving information on biologics: 1) current provision of information regarding the “biologics journey” and understanding of RA: in this theme, non-English-speaking patients expressed heightened anxiety about stepping up to biologics; 2) experience and perceptions of biologics: many patients were positive about the biologic experience; however, there were patient-perceived delays in getting on to the biologics; 3) factors influencing willingness to try biologics: in this theme, a number of factors were identified including seeking advice from doctors abroad; and 4) recommendations on the desired information to fully understand the use of biologics: some patients valued group discussions, while others suggested receiving RA and biologic information through a video interaction.
Conclusion: This novel study provides insight into South Asian RA patients’ experiences in and satisfaction toward receiving information about biologics. South Asian patients with RA reported a range of perceptions about biologics and support preferences, many of which may not be shared with the non-South Asian population
Vaccinia virus protein A46R targets multiple Toll-like-interleukin-1 receptor adaptors and contributes to virulence
Viral immune evasion strategies target key aspects of the host antiviral response. Recently, it has been recognized that Toll-like receptors (TLRs) have a role in innate defense against viruses. Here, we define the function of the vaccinia virus (VV) protein A46R and show it inhibits intracellular signalling by a range of TLRs. TLR signalling is triggered by homotypic interactions between the Toll-like-interleukin-1 resistance (TIR) domains of the receptors and adaptor molecules. A46R contains a TIR domain and is the only viral TIR domain-containing protein identified to date. We demonstrate that A46R targets the host TIR adaptors myeloid differentiation factor 88 (MyD88), MyD88 adaptor-like, TIR domain-containing adaptor inducing IFN-beta (TRIF), and the TRIF-related adaptor molecule and thereby interferes with downstream activation of mitogen-activated protein kinases and nuclear factor kappaB. TRIF mediates activation of interferon (IFN) regulatory factor 3 (IRF3) and induction of IFN-beta by TLR3 and TLR4 and suppresses VV replication in macrophages. Here, A46R disrupted TRIF-induced IRF3 activation and induction of the TRIF-dependent gene regulated on activation, normal T cell expressed and secreted. Furthermore, we show that A46R is functionally distinct from another described VV TLR inhibitor, A52R. Importantly, VV lacking the A46R gene was attenuated in a murine intranasal model, demonstrating the importance of A46R for VV virulence
Electromagnetically Induced Transparency (EIT) and Autler-Townes (AT) splitting in the Presence of Band-Limited White Gaussian Noise
We investigate the effect of band-limited white Gaussian noise (BLWGN) on
electromagnetically induced transparency (EIT) and Autler-Townes (AT)
splitting, when performing atom-based continuous-wave (CW) radio-frequency (RF)
electric (E) field strength measurements with Rydberg atoms in an atomic vapor.
This EIT/AT-based E-field measurement approach is currently being investigated
by several groups around the world as a means to develop a new SI traceable RF
E-field measurement technique. For this to be a useful technique, it is
important to understand the influence of BLWGN. We perform EIT/AT based E-field
experiments with BLWGN centered on the RF transition frequency and for the
BLWGN blue-shifted and red-shifted relative to the RF transition frequency. The
EIT signal can be severely distorted for certain noise conditions (band-width,
center-frequency, and noise power), hence altering the ability to accurately
measure a CW RF E-field strength. We present a model to predict the changes in
the EIT signal in the presence of noise. This model includes AC Stark shifts
and on resonance transitions associated with the noise source. The results of
this model are compared to the experimental data and we find very good
agreement between the two.Comment: 14 page, 15 figures, 1 tabl
- …
