2,344 research outputs found

    Analytical and computational estimation of patellofemoral forces in the knee under squatting and isometric motion

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    This study presents an intermediate step in prosthesis design, by introducing a newly developed two-dimensional mathematical, and a three-dimensional computational knee model. The analytical model is derived from Newton’s law with respect to the equilibrium equations, thus based on theoretical assumptions, and experimentally obtained parameter. The numeric model is built from an existing prosthesis, involving three parts as patella, femur and tibia, and currently it is under development. The models are capable to predict – with their standard deviation – the patellofemoral (numerically tibiofemoral as well) forces in the knee joint during squatting motion. The reason why the squatting is investigated is due to its relative simplicity and the fact, that during the movement the forces reach extremity in the knee joint. The obtained forces – as a function of flexion angle – are used firstly as fundaments to the knee design method, and secondly to extend the results related to the existing isometric kinetics, where one of the newly obtained functions appears as an essential – and so far missing – input function. Most results are compared and validated to the ones found in the relevant literature and put into a dimensionless form in order to have more general meaning

    VULNERABLE HOUSEHOLDS IN FLOOD-PRONE COMMUNITIES IN IBADAN: MEASURES TO IMPROVE THEIR STATUS WITHIN THE INCLUSIVE IBADAN CITY FRAMEWORK

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    The study assesses the impact of the last major flood disaster in Ibadan on the vulnerable groups (the poor, elderly, children and physically challenged). It investigates how vulnerable HHs have responded to post-disaster events. The study finds that HHs from 56% of the affected buildings suffered temporary displacement and 207 (7.4%) of the affected buildings were abandoned with Ibadan South-West LGA recording the highest cases of abandonment (23%).There exists a positive correlation between income and period of displacement (r=0.26) and a significant difference in the period of displacement across income groups. The study reveals disparities in access to relief/recovery items among the flood-affected populations. Urban dwellers had better access to relief packages than rural dwellers

    Consistency of the Two Higgs Doublet Model and CP violation in top production at the LHC

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    It is important to provide guidance on whether CP violation may be measurable in top-quark production at the Large Hadron Collider. The present work extends an earlier analysis of the non-supersymmetric Two-Higgs-Doublet Model in this respect, by allowing a more general potential. Also, a more comprehensive study of theoretical and experimental constraints on the model is presented. Vacuum stability, unitarity, direct searches and electroweak precision measurements severely constrain the model. We explore, at low \tan\beta, the allowed regions in the multidimensional parameter space that give a viable physical model. This exploration is focused on the parameter space of the neutral sector rotation matrix, which is closely related to the Yukawa couplings of interest. In most of the remaining allowed regions, the model violates CP. We present a quantitative discussion of a particular CP-violating observable. This would be measurable in semileptonically decaying top and antitop quarks produced at the LHC, provided the number of available events is of the order of a million.Comment: 45 pages, 10 figures, some in (essential) colour. Figures 2, 6 and 7 are bitmapped, better quality available on request. Version to appear in Nucl. Phys.

    Observations of Multiple Surges Associated with Magnetic Activities in AR10484 on 25 October 2003

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    We present a multiwavelength study of recurrent surges observed in H{\alpha}, UV (SOHO/EIT) and Radio (Learmonth, Australia) from the super-active region NOAA 10484 on 25 October, 2003. Several bright structures visible in H{\alpha} and UV corresponding to subflares are also observed at the base of each surge. Type III bursts are triggered and RHESSI X-ray sources are evident with surge activity. The major surge consists of the bunches of ejective paths forming a fan-shape region with an angular size of (\approx 65\degree) during its maximum phase. The ejection speed reaches upto \sim200 km/s. The SOHO/MDI magnetograms reveal that a large dipole emerges east side of the active region on 18-20 October 2003, a few days before the surges. On October 25, 2003, the major sunspots were surrounded by "moat regions" with moving magnetic features (MMFs). Parasitic fragmented positive polarities were pushed by the ambient dispersion motion of the MMFs and annihilated with negative polarities at the borders of the moat region of the following spot to produce flares and surges. A topology analysis of the global Sun using PFSS shows that the fan structures visible in the EIT 171 A images follow magnetic field lines connecting the present AR to a preceding AR in the South East. Radio observations of type III bursts indicate that they are coincident with the surges, suggesting that magnetic reconnection is the driver mechanism. The magnetic energy released by reconnection is transformed into plasma heating and provides the kinetic energy for the ejections. A lack of a radio signature in the high corona suggests that the surges are confined to follow the closed field lines in the fans. We conclude that these cool surges may have some local heating effects in the closed loops, but probably play a minor role in global coronal heating and the surge material does not escape to the solar wind.Comment: Accepted for the Publication in ApJ; 25 pages, 10 Figures, and 1 Tabl

    Analysis Of Relationship Between Preliminary Estimate, Tender Sum And Final Accounts (A Case Study Of Selected Building Projects In Edo State, Nigeria).

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    This research provides an analysis of the relationship between preliminary estimate, tender sum and final account of building projects with a view to predicting final account accurately from tender sum and preliminary estimate. To achieve the objectives, the study carried out extensive review of literature and collected data  interviews and administration of structured questionnaires. The data collected were analysed using multiple regression, correlation matrix and frequency distribution. The research reveals that there is a significant relationship between preliminary estimate, tender sum and final account of building projects. This research work has contributed to the existing body of knowledge in that it would help to provide reliable estimate for budgeting purposes. Key Words: Final account, Tender sum and Preliminary estimat

    Glass-formation region of ternary Sn-Sb-Se-based chalcogenide glasses

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    Tin-antimony-selenium (TAS)-based system belongs to the ternary chalcogenide compounds of IV-V-VI group owing to their heavy elemental masses, their glass formation region was assumed to be small comparing to their counterpart elements in the same group. However, there were rare published reports on their glass structure, while their glass boundary formation region was not yet reported. It was the aim of this paper to map their glass-forming region experimentally using XRD and validate it theoretically using the average co-ordination number, μ, and the fraction of the bond distributions, f, from chemical order model. Theoretically, it was validated that the glass formation was arrested between μ ≤ 2.4 and the fraction of Sn-Se bonds, f sn-se < 44.5%. XRD analyses of 66-as-prepared samples revealed that the glass formation region was located within the predicted area that mapped in structural triangle

    Static and Dynamic Strength Properties of a Fiber-Reinforced Compacted Cohesive Soil

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    Soil reinforcement with randomly oriented, individual synthetic fibers has been applied to laboratory specimens of a compacted cohesive soil. Fiber contents of up to 1.0% by soil dry weight were mixed with the soil. Data from unconfined compression (static) testing and resilient modulus (dynamic) testing have been presented. Experimental work showed that the fibers increased the soil unconfined compressive strength, ductility, toughness, static and dynamic energy absorption capacities, the resilient strain and the number of cycles to failure. The soil resilient modulus and the permanent strain both decreased with the increase in fiber content

    Performance of locally developed sunflower (Helianthus annuus L.) hybrids under irrigation

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    &nbsp;&nbsp;&nbsp; A field experiment was carried out at two locations, New Halfa and Rahad, for two cropping seasons, summer (2003/04) and winter (2004/05) at each location in a randomized complete block design with four replicates, to estimate the phenotypic and genotypic variability, heritability in broad sense and genetic advance for yield, yield components and other agronomic characters among 20 locally developed sunflower (Helianthus annuus L.) hybrids. Highly significant differences found between the evaluated hybrids for almost all characters at the four environments, except plant height at New Halfa, in summer, 1000- seed weight and seed yield at both locations in winter. Most of the variation for the morphological traits was due to genetic factors, whereas, the variation in yield and its components was due to environmental factors. High heritability estimate (&gt;60 %) coupled with low genetic advance for the morphological characters indicate epistatic and dominance nature of inheritance, while, the low heritability (&lt;60 %) coupled with high genetic advance for yield and its components, would indicate additive nature of inheritance. Therefore, direct selection for the morpholo-gical traits, based on the phenotype, among the hybrids may be effective, while selection for yield and yield components may not be effective. Thus, there is a need for a mechanism, other than simple selection, to improve yield in sunflower
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