10,584 research outputs found

    Foundation System for “ Akshardham” to Control Deformations Related to Probable Liquefaction

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    The paper presents a system of foundation for 38.0 m high monumental unique structure “ Akhsardham” on bank of “Yamuna” river at Noida ,New Delhi(India). The design is outcome of interaction of ideological requirements of Architects, Seismologist, Geotechnical and Structural engineers, as well as those empirical rules of Vastu- Shastra for religious places. The structure is typical flexible stone monument. It is located on alluvium of “Yamuna” river in seismic Zone IV of Bureau of Indian standards. The preliminary exploration report indicated liquefaction potential and suggested deep foundations. The engineering priests decided against use of steel for the structure expected to exist for 2-3 countries. The authors reviewed soil report, got quick check tests to for analysis of probability of liquefaction. Based on this studies and deliberations with the above agencies evolved economical massive foundation to fulfill requirements without compromising safety. The construction over foundation is in full swing

    Application of Case Studies to Practice in Foundation Engineering in India

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    India has massive developments, urbanization, housing, communication in last decade. The optimization of cost and saving construction time to complete, are now new aspects which geotechnical engineers are facing. Till today the typical design of shallow foundations of structure-buildings, fly over and dams on non-plastic silty fine sand subsoils found in alluvial deposits of state like Uttar Pradesh, Punjab, Gujarat, Bengal and long coastal belt, were designed by age old practice based on soil mechanics of 1948. Such proven practice became BIS codes for design and construction of structural foundations in 1976-81. The common sense and observational approach of Terzaghi (1959) did not confirm such interpretation of Standard Penetration (SP) test. SP test on non – plastic silty sand at 2 to 3 m below ground surface, being loose (Rd \u3c 15%), had permissible bearing capacity for 25 mm settlement (qa25) less than 100 kPa. This required almost double concrete in footings. Vast country with fast growth had more than million structures built/year, saving of RCC would be around 900 million cubic meter/year. The time reduced will be added advantage. Even up to 10m depth, at number of sites N recorded as 5 to 10 blows/30cm, was considered as “loose” to “medium” by the code indicating prima-facie high liquefaction potential under low seismic activity. This phobia did not spare proposed, under construction over years and existing structures from a long process of reinvestigations, consultants opinions and cost. High rise housing at Chennai, Delhi, Surat, monumental structures at Delhi, Agra, Ahmedabad, Kollkata, Panipat, Rajasthan suffered setback and perpetual suspense due to lack of proper interpretation. Some dams under construction like Ukai, Tenughat, barrages in West Bengal, Delhi, unique projects like Akshardham (Delhi) had to be stopped or delayed by suspected liquefaction. Long chain of opinions and additional tests like evaluation of Rd by alternative methods, rechecking of SPT values, blasting test as well as cross bore holes shear wave velocity tests had to be planned to remove notional interpretation. Study proposes to eliminate such decays & cost escalation by providing alternatives. Typical case studies, showing methodology are also illustrated. Authors with professionals (30 numbers) in geotechnical engineering practicing in India formed a TC-16 technical group (Year 2000-2005) to prepare a report on ground characterization by in-situ testing. The final recommendations for interpretation of SP test (N) and DCP test (NC) for non-plastic alluvial deposit, investigated as per IS code are presented in the form of a chart. It gives for observed N or NC at P0’ (effective overburden pressure) the relative density (Rd), ∅’ (angle of shear resistance), E (deformation modulus) and permissible bearing capacity for 40 mm permissible settlement. The chart also indicate likely liquefaction potential at depth for a = 0.1g for preliminary analysis. Typical case studies have been illustrated. The authors advocated bore holes to be supplemented by uncased DCPT adequate in number, to provide recommendation for an area (not point). If results are not satisfying commonsense, check by in-situ tests for Rd, plate load, even prototype test shall be used before resorting to rejection of site or adopting ground improvement. Any recommendation, for probable liquefaction for existing or under construction project, must be checked by proper reinvestigations and interpretation

    Helios-2 Vela-Ariel-5 gamma-ray burst source position

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    The gamma-ray burst of 28 January 1976, one of 18 events thus far detected in interplanetary space with Helios-2, was also observed with the Vela-5A, -6A and the Ariel-5 satellites. A small source field is obtained from the intersection of the region derived from the observed time delays between Helios-2 and Vela-5A and -6A with the source region independently found with the Ariel-5 X-ray detector. This area contains neither any steady X-ray source as scanned by HEAO-A nor any previously catalogued X-ray, radio or infrared sources, X-ray transients, quasars, seyferts, globular clusters, flare stars, pulsars, white dwarfs or high energy gamma-ray sources. The region is however, within the source field of a gamma-ray transient observed in 1974, which exhibited nuclear gamma-ray line structure

    A Note on Heat Transfer and Film Boiling

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    A Note on Heat Transfer and Film Boiling

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    <p>Descriptive statistics and bivariate correlations (Study 3).</p

    Finite-size behaviour of the microcanonical specific heat

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    For models which exhibit a continuous phase transition in the thermodynamic limit a numerical study of small systems reveals a non-monotonic behaviour of the microcanonical specific heat as a function of the system size. This is in contrast to a treatment in the canonical ensemble where the maximum of the specific heat increases monotonically with the size of the system. A phenomenological theory is developed which permits to describe this peculiar behaviour of the microcanonical specific heat and allows in principle the determination of microcanonical critical exponents.Comment: 15 pages, 7 figures, submitted to J. Phys.

    The effects of load and gradient on hand force responses during dynamic pushing and pulling tasks

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    The limited attention afforded to push/pull activities and the motion phases (initial, sustained and ending) characteristic of these tasks has prompted a research focus in this area. The present study examined biomechanical responses in the form of hand forces during dynamic submaximal trolley pushing and pulling. Participants pushed/pulled loads of 100, 200 and 300 kg on the level (determining impact of load) or pushed 100 kg along a 12° ramp (uphill and downhill- determining impact of gradient). During level exertions significant differences (p<0.05) in hand forces occurred between loads of 100 and 200 kg, and 100 and 300 kg for initial and sustained forces but not ending forces. Values were similar for pushing and pulling at respective loads and motion phases. Strong correlations indicate that initial forces can be used to accurately estimate sustained and ending forces. Importantly, correct technique is essential in force reduction. Forces were highest during uphill initial and sustained phases and the downhill sustained phase. For the initial phase, the forces were highest during uphill pushing (86.5 ± 25.73 N); for the sustained phase, there was no difference between uphill and downhill forces but level forces were significantly lower (18.19 ± 8.09 N) than either of the other two conditions; for the ending phase, the highest forces were produced during downhill pushing (-53.34 ± 13.65N). As sustained forces equaled or exceeded initial forces for uphill and downhill efforts, consideration of sustained forces may be appropriate in determining the inherent potential risk of graded pushing

    Nitrogen incorporation and trace element analysis of nanocrystalline diamond thin films by secondary ion mass spectrometry

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    Nitrogen has been successfully incorporated into nanocrystalline diamond films produced by a CH4/N-2 microwave plasma-enhanced chemical vapor deposition method. High mass resolution secondary ion mass spectrometry (SIMS) characterization shows that the density of the incorporated nitrogen, monitored via CN-, can be as high as 10(21) atoms/cm(3) depending on the ratio of CH4 to N-2 in the reactant gas and on the substrate temperature used for the film preparation. SIMS depth profiles demonstrate that the incorporated nitrogen is uniform within the diamond films (about 1.5 mu m thick) except at the surfaces and at the interface between film and substrate. Furthermore, the SIMS analyses reveal that alkali elements such as Na, K, and Li appear to be contaminants at the surface of nanocrystalline diamond films produced using a CH4/Ar or CH4/H-2 discharge, but are bulk impurities only for the films prepared using a CH4/N-2 plasma. These alkali impurities can play an important role in electronic properties such as electron field emissions of nanocrystalline diamond thin films

    Green Symbiotic Cloud Communications: Virtualized Transport Layer and Cognitive Decision Function

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    The evolution of the concept of cloud communications has posed a growing emphasis on virtual and abstract environments for the flow of information, structuring it in similitude to a natural cloud. The Green Symbiotic Cloud Communications (GSCC) paradigm created on this concept facilitates the use of multiple communication mediums concomitantly creating a first of its kind communication cloud. This paper specifically corroborates a virtualized transport layer and network ports and an abstracted Internet protocol scheme in defining the GSCC architecture. We further address the issue of formulating a cognitive decision function based on utility theory, which allows users with GSCC enabled devices to intelligently distribute its bandwidth requirement amongst the available communication mediums. Considering the multiple criteria associated with different networks we formulate an optimization problem to find the solution for this resource allocation problem for single user. We further address the multi-user scenario and formulate and solve the multi-objective optimization problem using goal attainment technique. Results in single and multiple user scenarios, demonstrate that by utilizing multiple mediums as per GSCC paradigm coupled with our proposed decision function improves the functionality of the communication cloud. The proposed architecture is dynamic and evolving, embedding greenness by efficiently utilizing the available resources as and when required. The multiple virtual links equate a linearly increasing relationship with the throughput achieved. Experimental results for both real time and static data through the proposed schematic are documented. The augmented paradigm enhances the quality of service, linearly increases throughput and increases the overall security in communications
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