Design and Behavior of Steel Delta Girders

In steel structures, I-sections are commonly used for beams and columns. These cross-sections usually lack lateral rigidity and torsional stiffness. An effective method to improve their lateral rigidity and overall flexural resistance is to weld two inclined rectangular plates to the compression flange and the compression portion of the web of hot-rolled or welded I-section to form what is known as a Delta girder. This mixed cross-section, i.e., cross-section composed of an open profile attached to a closed profile, can provide enhanced torsional stiffness and hence noticeably higher lateral-torsional buckling (LTB) capacity for the beam. While Delta girders can be used for any beams, their main applications are the design of crane runway and bridge beams and strengthening of existing beams. The main objectives of this dissertation are to study the static behavior of these girders and to provide a set of design equations for their nominal flexural and shear capacities. The research includes deriving closed-form equations for the cross-section properties of Delta girders. These equations are then verified against solutions obtained numerically. Using these cross-section properties, the theoretical lateral-torsional buckling capacity of Delta girders are determined and compared against results obtained from a finite element (FE) analysis. The results show that the theoretical LTB equation derived for general monosymmetric sections can be applied to these Delta girders. Additionally, it is shown that a simplified expression for the coefficient of monosymmetry βx derived for I-sections can be used in the computation of the elastic LTB capacity of Delta girders. A parametric study is then performed based on elastic LTB capacity to demonstrate the effectiveness of Delta girders in achieving a favorable capacity-to-weight ratio when compared to standard I-section members. A refined three-dimensional (3D) nonlinear inelastic FE models are then developed to examine the capacity of simply-supported Delta girders under uniform bending and pure shear. The models take into considerations the effects of initial geometrical imperfections and residual stresses on the behavior of Delta girders. The FE model and the modeling techniques used are verified against the experimental result of a test beam that failed by inelastic LTB. The analysis covers a comprehensive range of Delta girder dimensions based on the dimensions of standard hot-rolled European H- and I-sections. A sensitivity study on the effects of using reduced imperfections magnitudes shows up to 18.2% increase in the LTB capacity of the girder. Based on the FE LTB simulation results, it is shown that the buckling curve in the AISC (2016a) specifications overestimates the buckling capacity of Delta girders by an average of 9% and a maximum value of 21%. On the other hand, buckling curves “a” and “b” for rolled sections or equivalent welded sections case in the EuroCode 3 (2005) for Delta girders with d⁄bc ≤2 and d⁄bc \u3e2, respectively, provide an average difference of only 2% and a maximum difference of 7% in comparison to the FE results. Hence, these two curves are recommended for the LTB design of Class 1 (compact) Delta girders. Additionally, design recommendations are provided for selecting the proper delta stiffeners dimensions based on the cross-section geometries of the corresponding I-sections. Shear capacity equations for Class 1 (compact) Delta girders are proposed based on FE simulation results. The equations provide the option of selecting a conservative value that ignores strain hardening in the cross-section or a value that allows for some strain hardening to occur. In comparison to I-sections, the Delta girders analyzed in this study show an increase in shear capacity in the range of 41% to 89%. Furthermore, it is shown that in contrast to I-sections, yielding is a gradual process in Delta girders due to the presence of a non-uniform elastic shear stress distribution in the cross-section

Choledocholithiasis – diagnostic and treatment opportunities

Nicolae Testemitanu State University of Medicine and Pharmacy of the Republic of MoldovaBackground. Choledocolithiasis is a late complication in the evolution of biliary lithiasis. More frequently, the main bile duct approach is performed by new miniinvasive methods

Culture and Guarantees for Non-Repetition

II discussed the history and cultural significance of the political murals in Belfast and how the post-Good Friday Agreement and public policy on mural imagery have been to move away from direct conflict-related depictions in Northern Ireland. The presentation for the Transitional Justice Institute's 'Foundations of Transitional Justice' module explored the cultural approach to GNR and debated whether GNR is a state attempt of 'papering over the cracks.’ The presentation examined the rebranding of political murals in Northern Ireland as an example of culturally-focused GNR, including considering what is lost (specific identity) as well as what may be gained

Inclusivity and Place: Where a University and Neighbours Draw Together

For this participatory action research project Dr. Omar El Masri, a sociologist from the School of Natural, Social and Sports Sciences; Kimberly Ellen Hall, a senior lecturer in Illustration in the School of Arts; the University of Gloucestershire neighbours in Cheltenham; and our students are co-creating a mural in the neighbourhood around our campus. We are examining the relationship between the University community and the local population, which are often separate groups. We’re investigating if, by engaging in participatory action research through drawing to create a mural, we can contribute to the development of an inclusive social space. Drawing as a method of learning, communication, and community-building is the strand we will explore in this paper. The project is constructed of moderated-knowledge exchange workshops where we build collaboration through experimental drawing practices. Where we really see the outcome of our question is in the drawing we do as a group; stories are explored and the participants share in unexpected ways. As we learn from the sociological tradition of observational research, so we share the possibilities of collecting data through embodied image-making. Working collaboratively across both illustration and sociology brings a cross-disciplinary approach that informs both our research methodology and our teaching practice. Working outside of our campus offers us the opportunity to break down the walls between inside & outside. Co-creating a mural allows all involved to explore the visual communication of local stories through drawing practice. The outcomes of the mural include a sharable toolkit for community engagement with public art, which we will provide to local agencies like the Cheltenham Paint Festival in order to improve community empowerment for public art

THE CLINICAL BENEFIT OF SERUM PROCALCITONIN LEVELAS COMPARED TO BISAP SCORING SYSTEM FOR PREDICTINGTHE SEVERITY AND PROGNOSIS OF ACUTE PANCREATITIS

Background: Early accurate severity assessment of patients with acute pancreatitis (AP) is cruicial to decide on the acute management and predict outcomes and prognosis.This is done through multiple scoring systems of which serum procalcitonin (PCT) and BISAP has shown promising results. However,data comparing these methods is still conflicting. Objectives: we aim to assess the role of PCT as a sole indicator and compare it to BISAP in determining severity and prognosis of AP. Methods: Retrospective chart review of all AP cases between June 2012 and February 2017 at Makassed General Hospital, with at least one reading of PCT documented in records. Data regarding patients’ demographics and outcomes were collected. Procalcitonin levels and trends were compared to severity classes and BISAP scores regarding various outcomes of AP. Results: Forty-four patients met our inclusion criteria. Based on the revised Atlanta classification, 26 patients had mild, four moderate and 14 severe AP. Mean serum PCT levels were found to correlate with severity classes (1.28 with mild versus 4.81 with moderate-severe AP; P \u3c 0 .0001). This was even more prominent on follow-up testing after 48hours (1.67 vs 12.89 respectively; P=0.01). This proportional relation was again noted with BISAP scores of 0,1 and 2 where the mean PCT was 0.1,5.0 and 19.1 respectively. A trend of decrease in serial PCT was also noted with mild as compared to a trend of rising PCT in moderate-severe AP. Conclusion: Initial and serial PCT levels directly correlated with disease severity and might offer significant additional prognostic value in AP

The usage of recycled glass in hot mix asphalt: A review

Waste material has been defined as any type of material by-product of human or industrial activity that has no residual value. The elimination of waste glass in landfills become a serious challenging task which several countries look out on it on all sides of the world. Reusing of glass waste for road construction is a sustainable solution to environmental and ecological problems. Reusing of glass waste will reduce the construction cost of pavement, reduce the landfill cost. This study has done to review the overall performance of asphalt concrete blend, in which several exceptional combinations of aggregate is replaced with various proportions of crashed glass. This review is discussed some main properties of asphalt mixture, such as stability and flow. The results shown that the stability was higher than that of the glass waste samples and decreasing as the glass waste increasing. In general, the research displays that using glass waste in asphalt mixture is acceptable

Kurashha.co : Shaw Bottle Crusher / Aizat Fathullah Azman ...[et al.]

KURASHHA Co. is a small company that produce and sell pet bottles crusher at an affordable price. The company is established to encounter the problem faced by the public which is to ease people to recycle pet bottles and keep surrounding place clean

Mechanical properties of stone mastic asphalt incorporating glass fiber

Aims: To study the mechanical properties of stone mastic asphalt incorporating glass fiber. Background: Asphalt may become cracked, degraded, or otherwise flawed because of the combination of SMA surfaces and general degradation. SMA, when combined with glass fibre, has the potential to bring about advancements in the road industry. Objective: The use of glass fibres to enhance the mechanical characteristics of Stone Mastic Asphalt. Methods: Marshall stability test, Resilient modulus test, Dynamic creep test, and Abrasion test. Results: The presence of fibre may increase the performance of the apparent Stone Mastic Asphalt, and a composition including 3 percent glass fibre results in improved stability and stiffness. Conclusion: A quantity of glass fibre equal to three percent is the optimal proportion to be used in the process of increasing the mechanical characteristics of SMA. The performance of glass fibres with a lower volume per unit is better than those with the largest volume per unit

Improved reference genome of the arboviral vector Aedes albopictus

Background: The Asian tiger mosquito Aedes albopictus is globally expanding and has become the main vector for human arboviruses in Europe. With limited antiviral drugs and vaccines available, vector control is the primary approach to prevent mosquito-borne diseases. A reliable and accurate DNA sequence of the Ae. albopictus genome is essential to develop new approaches that involve genetic manipulation of mosquitoes. Results: We use long-read sequencing methods and modern scaffolding techniques (PacBio, 10X, and Hi-C) to produce AalbF2, a dramatically improved assembly of the Ae. albopictus genome. AalbF2 reveals widespread viral insertions, novel microRNAs and piRNA clusters, the sex-determining locus, and new immunity genes, and enables genome-wide studies of geographically diverse Ae. albopictus populations and analyses of the developmental and stage-dependent network of expression data. Additionally, we build the first physical map for this species with 75% of the assembled genome anchored to the chromosomes. Conclusion: The AalbF2 genome assembly represents the most up-to-date collective knowledge of the Ae. albopictus genome. These resources represent a foundation to improve understanding of the adaptation potential and the epidemiological relevance of this species and foster the development of innovative control measures