• Title/Summary/Keyword: Robertson

Search Result 96, Processing Time 0.027 seconds

The effect of small embankments on wind speeds

  • Quinn, A.D.;Robertson, A.P.;Hoxey, R.P.;Short, J.L.;Burgess, L.R.;Smith, B.W.
    • Wind and Structures
    • /
    • v.1 no.4
    • /
    • pp.303-315
    • /
    • 1998
  • Full-scale measurements have been made to determine the increase in wind speed over two exposed embankments, one of $23^{\circ}$ slope and 4.7 m in height, the other of $24^{\circ}$ slope and 7.3 m in height. Measurements were made at heights of 5, 10 and 15 m above the upper edge of each embankment and at the same heights approximately 100 m upwind in the lower-level approach fetch. Despite the modest sizes of the embankments, the maximum recorded increase in mean wind speed was 28% and the minimum was 13%; these increase relate to increases in wind loads on structures erected at the top of the embankments of 64% and 28% respectively. The associated increases in gust speeds are estimated at 33% and 18%, which imply increases in gust loading of 77% and 39% respectively. These experimental results are compared with predictions obtained from a computational fluid dynamics (CFD) analysis, using three high Reynolds number eddy-viscosity models and estimates from the UK wind loading code, BS 6399: Part 2. The CFD results are generally in agreement with the experimental data, although near-ground effects on the embankment crest are poorly reproduced.

Nonlinear analysis and design of concrete-filled dual steel tubular columns under axial loading

  • Wan, Cheng-Yong;Zha, Xiao-Xiong
    • Steel and Composite Structures
    • /
    • v.20 no.3
    • /
    • pp.571-597
    • /
    • 2016
  • A new unified design formula for calculating the composite compressive strength of the axially loaded circular concrete filled double steel tubular (CFDST) short and slender columns is presented in this paper. The formula is obtained from the analytic solution by using the limit equilibrium theory, the cylinder theory and the "Unified theory" under axial compression. Furthermore, the stability factor of CFDST slender columns is derived on the basis of the Perry-Robertson formula. This paper also reports the results of experiments and finite element analysis carried out on concrete filled double steel tubular columns, where the tested specimens include short and slender columns with different steel ratio and yield strength of inner tube; a new constitutive model for the concrete confined by both the outer and inner steel tube is proposed and incorporated in the finite element model developed. The comparisons among the finite element results, experimental results, and theoretical predictions show a good agreement in predicting the behavior and strength of the concrete filled steel tubular (CFST) columns with or without inner steel tubes. An important characteristic of the new formulas is that they provide a unified formulation for both the plain CFST and CFDST columns relating to the compressive strength or the stability bearing capacity and a set of design parameters.

Down the Rabbit Hole-Considerations for Ingested Foreign Bodies

  • Brown, Jerry;Kidder, Molly;Fabbrini, Abigail;deVries, Jonathan;Robertson, Jason;Chandler, Nicole;Wilsey, Michael
    • Pediatric Gastroenterology, Hepatology & Nutrition
    • /
    • v.22 no.6
    • /
    • pp.619-623
    • /
    • 2019
  • We report the case of a seven-year-old boy with an ingested foreign body, which was retained within the appendix for a known duration of ten months, ultimately requiring appendectomy. The ingested foreign body was incidentally discovered by abdominal x-ray at an emergency room visit for constipation. Despite four bowel cleanouts, subsequent x-rays showed persistence of the foreign body in the right lower quadrant. While the patient did not have signs or symptoms of acute appendicitis, laparoscopic appendectomy was performed due to the risk of this foreign body causing appendicitis in the future. A small metallic object was found within the appendix upon removal. This case highlights the unique challenge presented by foreign body ingestions in non-verbal or developmentally challenged children and the importance of further diagnostic workup when concerns arise for potential retained foreign bodies.

Modular reactors: What can we learn from modular industrial plants and off site construction research

  • Paul Wrigley;Paul Wood;Daniel Robertson;Jason Joannou;Sam O'Neill;Richard Hall
    • Nuclear Engineering and Technology
    • /
    • v.56 no.1
    • /
    • pp.222-232
    • /
    • 2024
  • New modular factory-built methodologies implemented in the construction and industrial plant industries may bring down costs for modular reactors. A factory-built environment brings about benefits such as; improved equipment, tools, quality, shift patterns, training, continuous improvement learning, environmental control, standardisation, parallel working, the use of commercial off shelf equipment and much of the commissioning can be completed before leaving the factory. All these benefits combine to reduce build schedules, increase certainty, reduce risk and make financing easier and cheaper.Currently, the construction and industrial chemical plant industries have implemented successful modular design and construction techniques. Therefore, the objectives of this paper are to understand and analyse the state of the art research in these industries through a systematic literature review. The research can then be assessed and applied to modular reactors.The literature review highlighted analysis methods that may prove to be useful. These include; modularisation decision tools, stakeholder analysis, schedule, supply chain, logistics, module design tools and construction site planning. Applicable research was highlighted for further work exploration for designers to assess, develop and efficiently design their modular reactors.

A Clinical Study of The Nasal Bone Fracture According to Stranc Classification (비골골절의 Stranc 분류에 따른 임상적 연구)

  • Park, Won Yong;Kim, Yong Ha
    • Archives of Plastic Surgery
    • /
    • v.35 no.3
    • /
    • pp.289-294
    • /
    • 2008
  • Purpose: The nasal bone fracture is known as the most common facial fracture. Several authors reported the classification of nasal bone fracture. Stranc classified the type of nasal fractures based on a pattern of impaction and level of injuries. Stranc classification proposed here is based on careful clinical observation and relates to both treatment and prognosis. The aim of this study is to determine any predictive value to the preoperative classification of nasal fracture, using the description by Stranc and Robertson. Methods: We reviewed 310 patients with nasal bone fracture treated at our hospital for last two years. Results: Lateral impact type of nasal bone fracture predominated more than frontal impact in the ratio of 2.3:1. The most common type of Stranc classification was lateral impact plane I(48.4%). Male predominated more than female in the ratio of 3:1. The most frequent age group was first decade(27.1%), second decade in frontal impact(30.5%), first decade in lateral impact (30.7%). The most common etiology was violence (31.3%) followed by slip down(21.3%), and traffic accident(18.1 %).The most common associated fracture was orbital(22.9%) followed by zygoma(10%), and maxilla (6.1%). The most common complication was septal deviation(20.0%) in frontal impact, and nasal deformity (26.0%) in lateral impact. The incidence of nasal deformity in lateral impact(26.0%) was more higher than frontal impact(15.8%) Conclusion: By assessing the pathomechanics and resultant degree of injury to the nasal skeleton, a better understanding of the treatment plan and prognosis was obtained. Using this information, satisfactory informed patient consent can be obtained.

An Evaluation of Suckling and Post Weaning Practices in Relation to the Stimulation and Ease of Detection of Oestrus in Nepalese Pakhribas Pigs

  • Shrestha, NP;Edwards, S.A.;English, P.R;Robertson, J.F.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.14 no.6
    • /
    • pp.765-770
    • /
    • 2001
  • Thirty second parity sows of the synthetic Nepalese Pakhribas genotype were used to investigate factors which might improve the occurrence and expression of estrus. The experiment had two sequential elements. In part 1, a change in suckling pattern was applied during lactation, and in part 2, different estrus detection methods were evaluated after weaning. All sows received the same pattern of weaning, which imitated the progressive weaning system used in Nepalese villages. Piglets from each litter were weaned at three ages (6, 7 and 8 weeks of age) in the proportion of 0.5 at 6 weeks followed by 0.25 at each of the subsequent weanings. In the first lactation treatment, the suckling pattern was left undisturbed, similar to the practice used in the villages in which the remaining piglets after first weaning are allowed continuous suckling. In the other treatment, the remaining piglets after first weaning were allowed to suckle their sows only during the night, whilst in the day time (09:00-16:00) they were excluded from the sow but left free to roam around. After weaning, estrus detection procedures were carried out in the absence or presence of two different boar stimuli: a synthetic boar pheromone spray or fresh boar urine. These were applied sequentially in a sequence of testing that alternated for each sow on a daily basis. The weaning to re-mating interval was significantly longer for the unrestricted suckling treatment. All sows were re-mated within 30 days after first weaning in the restricted suckling treatment groups, whereas only 71% of sows were re-mated within 30 days after weaning in the unrestricted suckling treatment groups ($x^2=3.877$, 1df, p<0.05). Both boar pheromone spray and boar urine increased the estrus detection probability, with no significant differences between the two stimuli treatments.

Factors Affecting Reproductive Performance in the Nepalese Pakhribas Pig: Effects of Nutrition and Housing during Lactation

  • Shrestha, N.P.;Edwards, S.A.;English, P.R.;Robertson, J.F.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.16 no.5
    • /
    • pp.644-649
    • /
    • 2003
  • The effects of housing and nutrition on the performance of first lactation sows of the Nepalese Pakhribas breed were investigated. A total of 36 sows, from a previous experiment on nutrition during gilt rearing, were allocated according to a factorial design with 2 levels of nutrition, 60 or 80% of the calculated lactation requirement, and two types of housing, traditional or improved. The mean live weight loss of sows during lactation was reduced to a slightly greater extent by improved housing (p<0.05) than by better nutrition (p<0.10). There was also a significantly lower loss of $P_2$ backfat thickness (p<0.05) and mean body condition score (p<0.05) for sows on the higher plane of nutrition. Piglet weight gain in early and mid lactation was influenced by gestation feeding of the gilt (p<0.10) and by housing (p<0.05). Late lactation gain was influenced only by lactation feeding (p<0.05). In consequence, piglet weight at 42 day weaning was increased to a similar extent by improved housing (p<0.05) and better lactation nutrition (p<0.01). Significantly more sows were remated by day 10 after weaning from a higher level of rearing nutrition ($x^2=13.57$, p=0.001), and from improved housing and improved lactation (both $x^2=4.57$, p=0.033). It is concluded that, under Nepalese village conditions, improvements in housing may be a more cost effective way of improving sow performance than expenditure on additional feed resources.

ON LORENTZIAN QUASI-EINSTEIN MANIFOLDS

  • Shaikh, Absos Ali;Kim, Young-Ho;Hui, Shyamal Kumar
    • Journal of the Korean Mathematical Society
    • /
    • v.48 no.4
    • /
    • pp.669-689
    • /
    • 2011
  • The notion of quasi-Einstein manifolds arose during the study of exact solutions of the Einstein field equations as well as during considerations of quasi-umbilical hypersurfaces. For instance, the Robertson-Walker spacetimes are quasi-Einstein manifolds. The object of the present paper is to study Lorentzian quasi-Einstein manifolds. Some basic geometric properties of such a manifold are obtained. The applications of Lorentzian quasi-Einstein manifolds to the general relativity and cosmology are investigated. Theories of gravitational collapse and models of Supernova explosions [5] are based on a relativistic fluid model for the star. In the theories of galaxy formation, relativistic fluid models have been used in order to describe the evolution of perturbations of the baryon and radiation components of the cosmic medium [32]. Theories of the structure and stability of neutron stars assume that the medium can be treated as a relativistic perfectly conducting magneto fluid. Theories of relativistic stars (which would be models for supermassive stars) are also based on relativistic fluid models. The problem of accretion onto a neutron star or a black hole is usually set in the framework of relativistic fluid models. Among others it is shown that a quasi-Einstein spacetime represents perfect fluid spacetime model in cosmology and consequently such a spacetime determines the final phase in the evolution of the universe. Finally the existence of such manifolds is ensured by several examples constructed from various well known geometric structures.

From Theory to Implementation of a CPT-Based Probabilistic and Fuzzy Soil Classification

  • Tumay, Mehmet T.;Abu-Farsakh, Murad Y.;Zhang, Zhongjie
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2008.03a
    • /
    • pp.1466-1483
    • /
    • 2008
  • This paper discusses the development of an up-to-date computerized CPT (Cone Penetration Test) based soil engineering classification system to provide geotechnical engineers with a handy tool for their daily design activities. Five CPT soil engineering classification systems are incorporated in this effort. They include the probabilistic region estimation and fuzzy classification methods, both developed by Zhang and Tumay, the Schmertmann, the Douglas and Olsen, and the Robertson et al. methods. In the probabilistic region estimation method, a conformal transformation is used to determine the soil classification index, U, from CPT cone tip resistance and friction ratio. A statistical correlation is established between U and the compositional soil type given by the Unified Soil Classification System (USCS). The soil classification index, U, provides a soil profile over depth with the probability of belonging to different soil types, which more realistically and continuously reflects the in-situ soil characterization, which includes the spatial variation of soil types. The CPT fuzzy classification on the other hand emphasizes the certainty of soil behavior. The advantage of combining these two classification methods is realized through implementing them into visual basic software with three other CPT soil classification methods for friendly use by geotechnical engineers. Three sites in Louisiana were selected for this study. For each site, CPT tests and the corresponding soil boring results were correlated. The soil classification results obtained using the probabilistic region estimation and fuzzy classification methods are cross-correlated with conventional soil classification from borings logs and three other established CPT soil classification methods.

  • PDF

Objective Outcomes of Closed Reduction According to the Type of Nasal Bone Fracture

  • Kang, Chang Min;Han, Dong Gil
    • Archives of Craniofacial Surgery
    • /
    • v.18 no.1
    • /
    • pp.30-36
    • /
    • 2017
  • Background: Nasal fractures have a tendency of resulting in structural or functional complications, and the results can vary according to the type of nasal bone fracture. The aim of this study was to evaluate the objective postoperative results according to the type of nasal bone fractures. Methods: We reviewed 313 patients who had a closed reduction of nasal bone fracture. The classification of nasal bone fracture by Stranc and Robertson was used to characterize the fracture type: frontal impact group type I (FI), frontal impact group type II (FII), lateral impact group type I (LI), lateral impact group type II (LII), and comminuted fracture group (C). For each patient, we tried to use the same axial image section of computed tomographic (CT) scans before and immediately after operation. Postoperative outcomes were classified into 4 grades: excellent (E), good (G), fair (F), and poor (P). We also analyzed postoperative complications by fracture type. Results: Regarding the postoperative CT images, 189 subjects showed E results, 99 subjects showed G, 18 subjects showed F, and 7 subjects showed P reduction. The rate of operation results graded as E by each fracture type was 66.67% in FI, 52.0% in FII, 64.21% in LI, 62.79% in LII, and 21.74% in C. Complications of FI (7.14%), LII (13.95%), and C (13.04%) groups occurred more than in the FII (4.00%) and LI (4.21%) groups. Conclusion: It seems that the operation result by fracture type was better in the FI, LI, and LII type than the FII and C type; after one month, however, LII type showed more complications than other types. The septal fracture can be thought to affect early reduction results in nasal bone fractures.