372 research outputs found
RELIABILITY ASSESSMENT OF FREE SPANNING OFFSHORE PIPELINE
Pipeline from offshore petroleum fields must have frequently prone to many threats such as corrosion, free spanning, extreme weathers and etc. This study will be only concentrated on free spanning of offshore pipeline. The presence of free span along the length of pipeline may result in excessive displacement and bending or vibration of the pipeline section. The research will begin with data gathering of pipeline from Malaysian Water Operation. All data related to the pipelines are gathered. This study is divided into three major parts which are the study of the length of pipeline span, bending moment capacity of pipeline and also the stress analysis in the pipeline. These are the three elements which can cause failure to the pipelines. Thus, an assessment analysis of free spanning pipeline is crucial in order to ensure the reliability of these pipelines. All equations are developed by using the data obtained f. Then, Limit State Function is developed for this research. From the limit state function, probability of failure of pipelines according to each category can be obtained. Softwareâs were used to conduct the study. Softwareâs that were used are BestFit, to get the distribution of the data and VaP to get the probability of the pipeline to fail. At the end of the research, all three failure modes is compared to get the best reliable mode according to the probability of failure for each mode
A similar phylogeographical structure among sympatric North American birches (Betula) is better explained by introgression than by shared biogeographical history
AimA comparative analysis of the chloroplast (cp) DNA structure of eastern North American birches (Betula) was undertaken to infer the impacts of Quaternary climate change on the phylogeographical structure of these species.LocationEastern North America.MethodsGenetic variation in chloroplast microsatellites (cpSSRs) and the psbAâtrnH intergenic spacer in Betula papyrifera, Betula alleghaniensis and Betula lenta was analysed in samples from 65, 80 and 12 populations, respectively. Coâoccurring Betula uber, Betula populifolia and Betula cordifolia were also sampled to examine haplotype relationships and account for potential introgression. Haplotype networks, Bayesian analysis and comparisons of RST and GST values were used to evaluate the phylogeographical structure. Genetic diversity within and among species was compared using rarefaction analysis.ResultsThe two most widespread species, B. papyrifera and B. alleghaniensis, showed high levels of haplotype diversity, while the Appalachian endemic B. lenta possessed a single haplotype. Bayesian analysis revealed three main phylogeographical groups for B. papyrifera and four groups for B. alleghaniensis, and these two species showed extensive regional haplotype sharing and a high introgression ratio.Main conclusionsWe postulate that at least three separate refugia contributed to the recolonization of B. papyrifera and B. alleghaniensis within eastern North America, while B. lenta appears to have recolonized from a single refugium. A high haplotype diversity of B. papyrifera and B. alleghaniensis in the Great Lakes region may reflect biogeographical contact between eastern and western lineages, with the potential influence of periglacial refugia. Similar phylogeographical patterns in the distantly related B. papyrifera and B. alleghaniensis represent a geographical turnover of the same locally shared haplotypes, pointing to introgression rather than shared biogeographical history as the mechanism. Although similar phylogeographical patterns are often interpreted as evidence for common biogeographical histories, our study demonstrates that such patterns can also arise through introgression.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110577/1/jbi12394.pd
AC electrokinetic phenomena over semiconductive surfaces: effective electric boundary conditions and their applications
Electrokinetic boundary conditions are derived for AC electrokinetic (ACEK)
phenomena over leaky dielectric (i.e., semiconducting) surfaces. Such boundary
conditions correlate the electric potentials across the
semiconductor-electrolyte interface (consisting of the electric double layer
(EDL) inside the electrolyte solutions and the space charge layer (SCL) inside
the semiconductors) under AC electric fields with arbitrary wave forms. The
present electrokinetic boundary conditions allow for evaluation of induced zeta
potential contributed by both bond charges (due to electric polarization) and
free charges (due to electric conduction) from the leaky dielectric materials.
Subsequently, we demonstrate the applications of these boundary conditions in
analyzing the ACEK phenomena around a semiconducting cylinder. It is concluded
that the flow circulations exist around the semiconducting cylinder and are
shown to be stronger under an AC field with lower frequency and around a
cylinder with higher conductivity.Comment: 29 pages, 4 figure
On the incompatibility of strains and its application to mesoscopic studies of plasticity
Structural transitions are invariably affected by lattice distortions. If the
body is to remain crack-free, the strain field cannot be arbitrary but has to
satisfy the Saint-Venant compatibility constraint. Equivalently, an
incompatibility constraint consistent with the actual dislocation network has
to be satisfied in media with dislocations. This constraint can be incorporated
into strain-based free energy functionals to study the influence of
dislocations on phase stability. We provide a systematic analysis of this
constraint in three dimensions and show how three incompatibility equations
accommodate an arbitrary dislocation density. This approach allows the internal
stress field to be calculated for an anisotropic material with spatially
inhomogeneous microstructure and distribution of dislocations by minimizing the
free energy. This is illustrated by calculating the stress field of an edge
dislocation and comparing it with that of an edge dislocation in an infinite
isotropic medium. We outline how this procedure can be utilized to study the
interaction of plasticity with polarization and magnetization.Comment: 6 pages, 2 figures; will appear in Phys. Rev.
Genetic structure and diversity of indigenous rice (Oryza sativa) varieties in the Eastern Himalayan region of Northeast India
The Eastern Himalayan region of Northeast (NE) India is home to a large number of indigenous rice varieties, which may serve as a valuable genetic resource for future crop improvement to meet the ever-increasing demand for food production. However, these varieties are rapidly being lost due to changes in land-use and agricultural practices, which favor agronomically improved varieties. A detailed understanding of the genetic structure and diversity of indigenous rice varieties is crucial for efficient utilization of rice genetic resources and for developing suitable conservation strategies. To explore the genetic structure and diversity of rice varieties in NE India, we genotyped 300 individuals of 24 indigenous rice varieties representing sali, boro, jum and glutinous types, 5 agronomically improved varieties, and one wild rice species (O. rufipogon) using seven SSR markers. A total of 85 alleles and a very high level of gene diversity (0.776) were detected among the indigenous rice varieties of the region. Considerable level of genetic variation was found within indigenous varieties whereas improved varieties were monoporphic across all loci. The comparison of genetic diversity among different types of rice revealed that sali type possessed the highest gene diversity (0.747) followed by jum (0.627), glutinous (0.602) and boro (0.596) types of indigenous rice varieties, while the lowest diversity was detected in agronomically improved varieties (0.459). The AMOVA results showed that 66% of the variation was distributed among varieties indicating a very high level of genetic differentiation in rice varieties in the region. Two major genetically defined clusters corresponding to indica and japonica groups were detected in rice varieties of the region. Overall, traditionally cultivated indigenous rice varieties in NE India showed high levels of genetic diversity comparable to levels of genetic diversity reported from wild rice populations in various parts of the world. The efforts for conservation of rice germplasm in NE India should consider saving rice varieties representing different types with specific emphasis given to sali and jum types. The protection against the loss of vast genetic diversity found in indigenous rice varieties in NE India is crucial for maintaining future food security in the changing world
Relocation consequences on an ophthalmology consultation service from an inpatient to outpatient facility
Importance This study shows that relocation of an academic ophthalmology residency program from an inpatient to an outpatient setting in western New York does not affect the consult volume but affects management patterns and follow-up rates. Objective To investigate the effects on the ophthalmology consultation service of an academic program with relocation from a Regional Level-1 Trauma center to an outpatient facility. Design Consultation notes from 3 years before and 3 years after the University at Buffaloâs (UB) Department of Ophthalmology relocation from a Regional Level-1 Trauma center (Erie County Medical Center) to an outpatient facility (Ross Eye Institute) were obtained from hospital electronic medical records and analyzed. Setting Hospitalized care and institutional practice. Participants All inpatient or Emergency Room Ophthalmology consultation patients from the Department of Ophthalmology at UB from 2004 to 2010 (1,379 patients). Exposures None, this was a retrospective chart review. Main outcome measures Patient demographics, reason for consult, diagnoses, and ophthalmic procedures performed by the UB Department of Ophthalmology before and after its relocation. Results Relocation to the outpatient facility did not affect consult volume (P=0.15). The number of consults focusing on ophthalmic conditions, as a percentage of the yearly total, rose 460% (P=0.0001), while systemic condition consults with ocular manifestations fell 83% (P=0.0001). Consults for ocular trauma decreased 65% (P=0.0034). Consults ending with a diagnosis of ânormal examâ fell, as a percentage of the yearly total (56%, P=0.0023), while diagnoses of new ocular conditions rose 17% (P=0.00065). The percentage of consults for Medicaid patients fell 12% (P=0.0001), while those for privately insured patients rose 15% (P=0.0001). The number of ophthalmic procedures did not change, but postconsult patient follow-up fell from 23% at the Erie County Medical Center clinic to 2% after the move to Ross Eye Institute, a â„97% decrease. Conclusion and relevance Relocation of UBâs academic Ophthalmology program from an inpatient department to an outpatient facility had no effect on its consultation patient or procedure volume, but it significantly affected the nature of consult diagnoses and decreased outpatient follow-up by \u3e90% at the latter location. Many hospitals are creating separate outpatient facilities that may experience similar obstacles
Evaluation of pulse-oximetry oxygen saturation taken through skin protective covering
BACKGROUND: The hard edges of adult finger clip probes of the pulse oximetry oxygen saturation (POOS) monitor can cause skin damage if used for prolonged periods in a neonate. Covering the skin under the probe with Micropore surgical tape or a gauze piece might prevent such injury. The study was done to see if the protective covering would affect the accuracy of the readings. METHODS: POOS was studied in 50 full-term neonates in the first week of life. After obtaining consent from their parents the neonates had POOS readings taken directly (standard technique) and through the protective covering. Bland-Altman plots were used to compare the new method with the standard technique. A test of repeatability for each method was also performed. RESULTS: The Bland-Altman plots suggest that there is no significant loss of accuracy when readings are taken through the protective covering. The mean difference was 0.06 (SD of 1.39) and 0.04 (SD 1.3) with Micropore and gauze respectively compared to the standard method. The mean difference was 0.22 (SD 0.23) on testing repeatability with the standard method. CONCLUSION: Interposing Micropore or gauze does not significantly affect the accuracy of the POOS reading. The difference between the standard method and the new method was less than the difference seen on testing repeatability of the standard method
An interdisciplinary approach towards improved understanding of soil deformation during compaction
International audienceSoil compaction not only reduces available pore volume in which fluids are stored, but it alters the arrangement of soil constituents and pore geometry, thereby adversely impacting fluid transport and a range of soil ecological functions. Quantitative understanding of stress transmission and deformation processes in arable soils remains limited. Yet such knowledge is essential for better predictions of effects of soil management practices such as agricultural field traffic on soil functioning. Concepts and theory used in agricultural soil mechanics (soil compaction and soil tillage) are often adopted from conventional soil mechanics (e.g. foundation engineering). However, in contrast with standard geotechnical applications, undesired stresses applied by agricultural tyres/tracks are highly dynamic and last for very short times. Moreover, arable soils are typically unsaturated and contain important secondary structures (e.g. aggregates), factors important for affecting their soil mechanical behaviour. Mechanical processes in porous media are not only of concern in soil mechanics, but also in other fields including geophysics and granular material science. Despite similarity of basic mechanical processes, theoretical frameworks often differ and reflect disciplinary focus. We review concepts from different but complementary fields concerned with porous media mechanics and highlight opportunities for synergistic advances in understanding deformation and compaction of arable soils. We highlight the important role of technological advances in non-destructive measurement methods at pore (X-ray tomography) and soil profile (seismic) scales that not only offer new insights into soil architecture and enable visualization of soil deformation, but are becoming instrumental in the development and validation of new soil compaction models. The integration of concepts underlying dynamic processes that modify soil pore spaces and bulk properties will improve the understanding of how soil management affect vital soil mechanical, hydraulic and ecological functions supporting plant growth
Makna penyertaan dalam program pembangunan komuniti: satu tinjauan dari sudut pandangan dunia komuniti Bidayuh luar bandar
Kajian ini adalah tentang perbezaan antara makna penyertaan yang dikonseptualisasikan oleh agen pentadbir (tahap
makro) dengan persepsi penyertaan dan keperkasaan yang dikonstruk berdasarkan pandangan dunia komuniti
Bidayuh itu sendiri (tahap mikro). Jurang teoritikal adalah isu yang hendak diterokai dan dibincangkan dalam
makalah ini. Bagi tujuan itu, kajian ini menggunakan pendekatan tafsiran logik abduktif berasaskan ontologi idealis
dan epistemologi konstruksionis. Kajian ini dijalankan di Daerah Serian, Sarawak. Menggunakan teknik
persampelan bertujuan, sejumlah 50 orang informan telah ditemu bual secara mendalam diikuti dengan
perbincangan kumpulan secara tak formal. Hasil kajian mendapati penyertaan yang difahami oleh komuniti Bidayuh
tidak terhad di peringkat pelaksanaan sahaja tetapi turut melibatkan peringkat yang lain seperti perancangan,
penilaian dan pemantauan. Selain itu, ia turut melibatkan kemampuan mereka dalam memahami, menginterpretasi
masalah yang dihadapi dan kemudiannya mentakrifkan keperluan serta menterjemahkannya kepada proses tindakan
melalui penyertaan dalam organisasi itu sendiri
Referrals to a facial pain service
AIM: To assess the quality of referral letters to a facial pain service and highlight the key requirements of such letters.
METHOD: The source of all referral letters to the service for five years was established. For one year the information provided in 94 referrals was assessed. Using a predetermined checklist of essential information the referral letters were compared to these set criteria.
RESULTS: The service received 7,001 referrals and, on average, general dental practitioners (GDPs) referred 303 more patients per year than general medical practitioners (GMPs). Seventy-one percent of all referrals were from primary care practitioners, the rest were from specialists. Over 70% of GMP and 52% of GDP letters included a past medical history, with GMPs more likely to suggest a possible diagnosis and include previous secondary care referrals. The mean score for GMP referrals compared to the standard proforma (maximum of 12) was 5.6 and for GDP referrals 5.0. A relevant drug history was included by 75.6% GMP compared to 38.7% of GDPs. GMPs were more likely to include any relevant mental health history.
CONCLUSIONS: The overall quality of referral letters is low which makes it difficult for the specialists to provide robust treatment plans
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