Investigation and prediction of urban-sprawl and land-use changes for Chennai city using geo-spatial technologies

1443-1451Monitoring urban sprawl is a vital component to assess landscape changes as it directly affects the quality of life. Multi date land-use and land-cover thematic layers were generated using multi-date high resolution remote-sensing data and Survey of India topo-sheet and spatial changes in urban land-use and urban-sprawl were studied using GIS. The residential and commercial urban area of city increased from 14,865.8 and 2,121.27 hectares in 1991 to 35,564 and 3,527.34 hectares in 2014. This study revealed that 51% of agricultural land and 2% of water bodies have been transformed as other urban land use features, in the form of built-ups. Based on current landscape trends, a 29-year forward simulation for the years 1991 to 2020 was performed using GIS land use change modeller analysis tool. The results show that by 2020 the residential and commercial urban of Chennai would increase to 51,059 and 4,246.7 hectares, respectively

Constructing Local Sea Level Rise Scenarios for Assessing Possible Impacts and Adaptation Needs: Insights from Coasts of India

Rising seas are one of the crucial impacts of global warming. Rise in the mean sea level may impact coastal communities under an increasingly warming climate. The coastal zones are highly resourceful and dynamic. The coastal zones are facing many natural hazards such as erosion, storm surge, tsunami, coastal flooding and sea level rise. It is projected to have a three-time expansion of density of population in the coastal areas, and 50% of the world’s population will be occupied within the vicinity of 100 km of coastal areas. India has a very long coastline of 7500 km and covers 16.7% of the world’s population and has a very high population growth rate which itself make India highly sensitive to these environmental challenge. Projections of mean global sea level rise (GSLR) provide insufficient information to plan adaptive responses; local decisions require local projections that accommodate different risk tolerances and time frames and that can be linked to storm surge projections. Therefore, in this chapter, the main endeavor is to identify and compare coastal vulnerability to projected future sea level rise. In order to project the sea level rise at local level, a climate- and sea level rise simulator model output based on IPCC AR5 (Special Report on Emission Scenarios) has been employed under different scenarios. The results reveal that sea level for Visakhapatnam, Chennai, Cochin and Mumbai may increase by 1.16, 1.19, 1.34, 1.24 m, respectively, by 2100 under the high-emission business as usual carbon pollution scenario under IPCC AR5 Representative Concentration Pathway. The sea level of west coast tends to rise slightly more than the east coastal areas of India. These estimates have great potential for the coastal regulatory authority and other decision-makers to take precautions with regard to inundations of low-lying areas and to conserve India’s eco-sensitive coastal resources

Experimental Investigations of the Stress Path Dependence of Weakly Cemented Sand

Cohesion between grains in a geological system is perhaps the simplest and ideal representation of a range of material systems including soft rocks, structured soils, mudstones, cemented sands, powder compacts, and carbonate sands. This presence of inter granular cohesion is known to alter the ensemble mechanical response when subjected to varied boundary conditions. In this study, a hollow cylinder apparatus is used to investigate the mechanical behavior of weakly cemented sand ensembles by mapping the state boundary surfaces including the failure surface (locus of peak stress state) and the state of plastic flow (locus of final stress state). When these materials are sheared, the plastic deformation accumulates due to breakdown of cohesion between the grains, which introduces a lag in occurrence of peak stress ratio and maximum dilatancy, unlike a typical frictional granular material. This breakdown of cementation is affected by changes in the initial mean effective stress, initial reconstitution density, and intermediate principal stress ratio (stress path on the octahedral plane). The final state locus, emergent at large strains, was found to depend on the initial reconstitution density. Further, the parameters are extracted for calibration and prediction exercise using an elastic plastic constitutive model. In this and several other models, the effect of cementation is considered as an additional confinement to the ensemble. Such an approach predicts the stress state precisely but does not predict the volumetric response accurately, especially at large strains

Experimental Studies on The Mechanical Behaviour of Cohesive Frictional Granular Materials

Thss thesis presents the results of an experimental programme on the static mono-tonic response of cohesive-frictional granular materials. The purpose of this experimental programme was to gain insight into the mechanical behaviour of uncemented sands, and sands with small percentages of cementation. With this objective in sight, the research involved understanding and delineating the e ects of four variables: the intermediate principal stress, stress inclination, cohesion (or cementation), and particle morphology. The hollow cylinder torsion (HCT) apparatus, which allows control over both the magnitude and direction of principal stresses, was used in this study to carry out a series of elemental tests on the model materials. The test results were analysed in a plasticity theory based framework of critical state soil mechanics. Drained and undrained HCT tests were conducted on a model angular sand to understand the combined influence of intermediate principal stress ratio (b) and principal stress inclination ( ). Sand specimens were reconstituted to a given density and confining pressure, and were sheared to large strains towards a critical state. The stresses at the critical state with varying `b' were mapped on an octahedral plane to obtain a critical state locus. The shape of this locus closely resembles a curved triangle. Also these specimens showed increased non-coaxiality between the stress and strain increment directions at lower strains. This non-coaxiality decreased significantly, and the response at the critical state was by and large coaxial. The effect of `b' and ` ' on the flow potential, phase transformation, and critical state was also investigated. At phase transformation, ` ' plays a more dominant role in determining the flow potential than `b'. The shape and size of the critical state locus remained the same immaterial of the drainage conditions. Next, small amounts of cohesion (using ordinary Portland cement) was added to this sand ensemble to study the mechanical behaviour of weakly cemented sands. The peak in the stress strain curve was used to signal the breakdown of cohesion further leading to a complete destructuring of the sand at the critical state. The response of the cemented sand changes from brittle to ductile with increase in confining pressure, while reverses with increase in density and `b'. Stress-dilatancy response for the weakly cemented materials shows the non coincidence of peak stress ratio and maximum value of dilation unlike purely frictional materials. This mismatch in peak stress ratio and maximum dilation diminishes with increase in confining pressure. The peak stress (cemented structured sand) locus and the critical state (destructured) locus were constructed on the octahedral plane from these HCT tests. The critical state locus of the cemented sand when it is completely destructured almost coincides with the critical state locus of the clean sand. Using this experimental data set, some important stress-dilatancy relationships (like Zhang and Salgado) and failure criteria (Lade's isotropic single hardening failure criteria and SMP failure criteria) were benchmarked and their prediction capabilities of such models were discussed in detail. The effect of particle morphology was also investigated in this testing programme. Rounded glass ballotini and angular quartzitic sand which occupy two extreme shapes were selected, and a series of HCT tests at different `b' values were con-ducted. A larger sized CS locus was obtained for angular particles and it encompassed the critical state locus of the spherical glass ballotini. Spherical particles exhibit a predominantly dilative behaviour, however present a lower strength at the critical state. The mobilization of strength as a result of rearrangement of angular particles and the consequent interlocking is higher. Even with contractive behaviour which is reflected in the higher values of critical state friction angle and the larger size of the yield locus for sand. Finally, a series of unconfined compression tests were performed to understand if there exists a scale separation in cohesive frictional materials. Specimens were reconstituted to a range of sizes while maintaining a constant aspect ratio and density. As the specimen size increased, the peak strength also increases, counter to an idea of a generalized continuum for all model systems. The observed secondary length scale (in addition to the continuum length scale) is obverse to the one observed in quasi-brittle materials such as concrete, rock. In order to ascertain the reason behind this phenomenon, a series of tomography studies were carried out on these contact-bound ensembles. The presence of cohesion between the grains brings about an \entanglement" between the grains, which contributes to increase in strength, with increase in the size of the sample. This in e ect bringing forth a second length scale that controls the behaviour of these cohesive frictional granular materials. This experimental data set provides quantification of various aspects of the me-chanical response of both cemented and uncemented granular materials under myriad stress conditions. This data set is also extremely useful in developing and bench-marking constitutive models and simulations

Institutionalizing quality within national health systems: Key ingredients for success

Quality improvement initiatives can be fragmented and short-term, leading to missed opportunities to improve quality in a systemic and sustainable manner. An overarching national policy or strategy on quality, informed by frontline implementation, can provide direction for quality initiatives across all levels of the health system. This can strengthen service delivery along with strong leadership, resources, and infrastructure as essential building blocks for the health system. This article draws on the proceedings of an ISQua conference exploring factors for institutionalizing quality of care within national systems. Active learning, inclusive of peer-to-peer learning and exchange, mentoring and coaching, emerged as a critical success factor to creating a culture of quality. When coupled by reinforcing elements like strong partnerships and coordination across multiple levels, engagement at all health system levels and strong political commitment, this culture can be cascaded to all levels requiring policy, leadership, and the capabilities for delivering quality healthcare.Fil: Kandasami, Stephanie. No especifíca;Fil: Babar Syed, Shamsuzzoha. No especifíca;Fil: Edward, Anbrasi. No especifíca;Fil: Sodzi Tettey, Sodzi. Institute for Healthcare Improvement; Estados UnidosFil: Garcia Elorrio, Ezequiel. Instituto de Efectividad Clínica y Sanitaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mensah Abrampah, Nana. No especifíca;Fil: Hansen, Peter M.. No especifíca

COMPARISON OF TOP HEIGHT AND DOMINANT HEIGHT WITH TREE VARIABLES AT THE EVEN AGED Pinus caribaea (MORELET) PLANTATION AT YAGIRALA

Top height and dominant heights are 'Confusedlyinterpret in many countries. The mainaim of this study was find the similarity of above two terms and to build some models topredict them.The study was carried out in Yagirala 25 year old even aged Pinus caribaea plantation.Top height and dominant heights were compared with other tree variables. Stratifiedrandom sampling without replacement was used to select the sampling unit. Circular plotsof 0,05 hectare with slope correction and boundary adjustment were used to obtain therequired tree measurementsDiameter at breast height, total height, lower and upper crownheight were measured andbasal area and crown depth were calculated. Top height and dominant height were alsoestimated.Results indicated that there is a significant difference between top and dominant heights.Also two separate equations to predict these two heights were developed. According to theresults initially ten equations were selected. Five equations described the relationshipbetween top and total height while the other five described the relationship betweendominant height and total height. Finally the best two equations were selected usingcoefficient of variation values and the distributions of standard residuals.

Numerical study on the hydrate rich sediment behaviour during depressurization

Exploratory studies have been carried out to identify the potential natural gas hydrate reserves for commercially producing gas. While extracting the gas from the hydrate-bearing sediments using various dissociation techniques, there will be a significant loss of strength in these sediments. It is well known that the behavior of gas hydrate sediments is governed by Thermo Hydro Mechanical Chemical ­ THMC coupled process during the gas extraction. Thus, in this study, in order to understand the influence of depressurization at the well-bore and the permeability of the hydrate reservoir on the sediment deformation characteristics, a 2D (plane strain condition) hydrate reservoir is simulated (using a multiphase numerical schema). From the study, it is observed that the flow response, i.e., the rate of change of gas pressure near the well-bore, decreases with the increase in the duration of the extraction. The maximum settlement occurs for reservoirs having low well-bore pressure (higher amount of depressurization) and high intrinsic permeability. Additionally, these same reservoir conditions also lead to maximum cumulative gas production. Thus, the continuous gas extraction results in a highly porous medium that is stabilized primarily due to the geomechanical changes

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication