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Singh R.B.,Independent Consultants
Long Span Bridges and Roofs - Development, Design and Implementation | Year: 2013

The Planning and Design of Bridges is part art and part compromise which is most significant of aspect of Structural Engineering. It demonstrates the creative capability, imagination, innovation and exploration of the Designer .Bridge design is a Complex Engineering problem. For planning of Bridge at a particular site, it is essential to consider many factors, such as the need for a bridge, the present and future traffic, stream characteristics, subsoil condition, alternative sites, aesthetics and cost. It may not be possible always to have a wide choice of sites for a bridge. It may not be possible to have a wide choice of sites for a Bridge particularly in case of Bridges in Urban Areas & Flyovers. In India, past two decades have seen unprecedented growth of knowledge in the field concrete bridges, development of new structural forms, new methods of computer-based analysis and design and development of high strength materials. A new code IRC:112-2011 based on Limit State Method has been issued which will be very useful for design of long span bridges. Continuous Long Span Bridges spanning more than 60 m are provided over valleys, rivers .streams, marshaling yards & locations where the soil conditions, water currents, pier heights, traffic conditions etc may warrant. The design of long span Bridges is a Challenge to the ingenuity and perseverance of the Designer .Every long span Bridge poses new problems in design concepts & new construction details Long span concrete bridges are usually post tensioned pre stressed concrete and are constructed either as a continuous beam types or free cantilever structures. Many methods have been developed for continuous deck construction. If the clearance between the ground and bottom of deck is small and the soil is firm, the superstructure can be built on staging. But this method is becoming obsolete. Currently free cantilever and movable scaffold system are being used to save time and to improve safety. Arch Bridges have been built since Ancient times. There are known examples of Babylonian Masonry Arch Bridges and Chinese /Roman stone Arches. Some of them are still in use. The arch form is best suited to deep gorges with steel rocky banks which furnish natural abutments to receive the heavy thrust from the arch .The arch form is aesthetically the most pleasing and have been used in steel bridges with span range of 100-250 m Any body seeing a Bridge will have clear idea whether he or she likes it or not. The impression is independent of the Technical knowledge. It is directly inspired by the lines & proportions of the Bridge. Old Howrah bridge at Kolkata is a steel truss. Such a mighty river like Ganga could have been bridged by better looking structure. If compared with Golden Gate Bridge in Sanfransico, USA which has become a landmark of the environment. Many foreign tourist to USA with certainly go to just see and enjoy the beauty of the Bridge. Source

Ringrose S.,Independent Consultants | Ringrose S.,University of Botswana | Cassidy L.,Ecosurv Environmental Consultants | Cassidy L.,University of Botswana | And 6 more authors.
Earth Surface Processes and Landforms | Year: 2014

The Boteti palaeo-estuary in northern Botswana is located where the endoreic Boteti river, an overflow from the regional Okavango river system, enters the Makgadikgadi pans. The present work considers diagenetic silica and calcium carbonate dominated transformations. The aims are to help identify precursor conditions for the origin of microcrystalline silcrete-calcrete intergrade deposits while developing insight into pene-contemporaneous silica and calcite matrix formation. General precursor conditions require the presence of cyclical endoreic freshwater inflow into a saline pan. The pan should be deep enough to sustain a permanent watertable under climatic conditions sufficient to cause carbonate fractionation within the groundwater. Freshwater inflow into a saline pan drives the geochemistry of the system (from freshwater to saline, from neutral to high pH). The geochemistry is controlled by the periodicity of inflow relative to salinity levels of phreatic groundwater in the receptor saline pan. The source of most silica and localized CaCO3 is derived from the dissolution and precipitation of micro-fossils, while more general CaCO3 enrichment stems from saline pan based carbonate fractionation. Diagenetic change leads to colloidal then more consolidated bSiO2/CaO aggregate formation (amorphous silica) followed by transformations into opaline silica over time. Irregular zones of siliceous sediment forming in otherwise calcareous deposits may relate to the irregular occurrence of biogenic silica in the source sediments, inferring a source for local silica mobilization in intergrade deposits. The distribution of calcareous micro-fossils may have a similar converse effect. Diagenetic evidence from an intergrade deposit with a low SiO2/CaO ratio suggests that transformation occurred more into the pan, while an intergrade deposit with a high SiO2/CaO ratio more likely formed closer to a land margin and was frequently inundated by freshwater. Pene-contemporaneous silcrete-calcrete intergrade formation under the above conditions may take place where dissolved silica crystallizes out in the vicinity of calcite crystals due to local decreases in pH. The continuing consolidation of bSiO2/CaO aggregates may be facilitated by the presence of increasing amounts of calcite. It appears that CaCO3 may act as a catalyst leading to pene-contemporaneous bSiO2/CaO aggregate formation. However the processes involved require further work. © 2013 John Wiley & Sons, Ltd. Source

Tileva M.,Independent Consultants | Biermann E.,Independent Consultants
Social Science and Medicine | Year: 2011

The Iraq conflict resulted in the largest displacement in the Middle East in recent history, and provision of health services to the displaced population presents a critical challenge. With an increase in the number of people affected by complex emergencies and the number of people displaced in urban settings, the international community must adapt intervention strategies to meet the specific demands and contexts of this population. The study aimed to provide information on food security and livelihoods for Iraqi refugees in Syria and Jordan to inform humanitarian assistance planning. National cross-sectional cluster sample surveys of displaced Iraqi populations displaced were conducted in Jordan (October 2008) and Syria (March 2009). Clusters of ten households were randomly selected using probability-based sampling; a total of 1200 and 813 Iraqi households in Jordan and Syria, respectively, were interviewed about food security and receipt of humanitarian assistance. In Syria, 60% of households reported the household food situation had declined since the arrival period as compared to 46% in Jordan. Food aid receipt was reported by 18.0% of households in Jordan and 90.3% of households in Syria. In Jordan, 10.2% of households received cash assistance and in Syria 25.3% of households received cash assistance. In Jordan, cash assistance was associated with low socioeconomic status, large household size, and UNHCR registration. In Syria, female headed households, Damascus residents, families with children, and those registered with UNHCR were more likely to receive cash assistance. Food insecurity remains a concern among displaced Iraqi households in both Jordan and Syria. Improved targeting of both food and cash assistance and the expansion of cash-based programs could lead to a more effective use of funds and facilitate the implementation of assistance programs that are sustainable in the context of declining funding availability. © 2010 Elsevier Ltd. Source

Javier B.-P.,University of Veracruz | Obregon-Noriega V.,Independent Consultants | Grageola-Nunez J.C.,Independent Consultants | Cruz-Nieto M.A.,Pronatura Noroeste A.C | Carmona-Islas C.,University of Veracruz
Ocean and Coastal Management | Year: 2013

In this paper we describe the development of the software TreeDSS, a user-friendly decision support system, developed as a central component of the project "The wetlands corridor of the Gulf of California (WCGC)". It aims to provide a support tool to partners of the project for structuring and solving frequent multicriteria evaluation problems, such as suitability and vulnerability assessment, resource allocation and zoning. TreeDSS basically allows users to build decision trees by coding expert knowledge using a friendly graphical interface and couples automatically with the geographic information software ArcMap 9.3 to present results both, as tables and maps, making it possible for evaluators reviewing criteria, ranges and decisions reached in real time. To illustrate how the software can be used in a real management situation, we present, as case study the development of a suitability assessment model to identify potential feeding grounds for migratory birds along the WCGC. © 2013 Elsevier Ltd. Source

Mehio A.K.,Boston University | Lerner J.H.,DePuy | Engelhart L.M.,DePuy | Kozma C.M.,Independent Consultants | And 3 more authors.
American Journal of Neuroradiology | Year: 2011

BACKGROUND AND PURPOSE: Previous studies evaluating vertebral augmentation procedure costs have not made detailed comparisons between vertebroplasty and kyphoplasty. Our study contrasts hospital costs for vertebroplasty versus kyphoplasty for the treatment of vertebral compression fractures in routine clinical practice in the United States. MATERIALS AND METHODS: This retrospective cohort study analyzed 2007-2008 hospital discharge and billing records from the Premier Perspective data base. The primary outcome variable, differences in total hospital cost between vertebroplasty and kyphoplasty, was assessed by using analysis of covariance. RESULTS: Three thousand six hundred seventeen patients received vertebroplasty (64% inpatient, 36% outpatient), and 8118 received kyphoplasty (54% inpatient, 46% outpatient). Approximately 75% were women, and most were white. Mean total unadjusted inpatient costs were $9837 for vertebroplasty versus $13 187 for kyphoplasty (P < .0001). Outpatient vertebroplasty costs were $3319 versus $8100 for kyphoplasty (P < .0001). Lower vertebroplasty costs were largely due to differences in hospital supply and OR. Mean vertebroplasty OR costs were $73.60 (anesthesia), $112.06 (recovery room), and $990.12 (surgery) versus $172.16 (anesthesia), $257.47 (recovery room), and $1,471.49 (surgery) with kyphoplasty. Adjustments for age, sex, admission status, and disease severity accentuated the differences. Mean adjusted inpatient costs were $11 386 for vertebroplasty versus $16 182 for kyphoplasty (P < .0001), and outpatient costs were $2997 for vertebroplasty versus $7010 for kyphoplasty (P < .0001). After adjustments for the same covariates, length-of-stay differences were no longer evident (P = .4945). CONCLUSIONS: Performing vertebroplasty versus kyphoplasty reduces hospital costs by nearly $5000 for inpatient procedures and by more than $4000 for outpatient procedures. Source

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