Emerging science for nuclear test monitoring

Engineering Sciences and Technology Journal (ESTJ), Volume 2, Jan 2017

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Abstract
Ongoing research and development efforts enable future capabilities to better counter threats posed by weapons of mass destruction. Cooperative research with global partners improves international collaboration to detect and characterize weapons of mass destruction, and enhances a host nations sustainment of scientific programs. Recent topics that are relevant to the CTBTO identify science focus areas to address challenges of an on-site inspection. Recent topics have included research for a number of basic science areas. For example radiation sensitive materials that change their optical properties and novel sensing materials used as indicators of container or seal integrity between inspections will be explored. These novel sensing materials can help provide unique assurance against tampering to assist verification. In addition integration of multiple sensor technologies and techniques using advanced mathematical methods to improve seismic location algorithms and modeling of explosions. More general topics that are planned for the future and that are relevant to the International Monitoring System and International Data Center include: alternative remote sensing materials and methods; new methods and modeling for radiochemical analysis, sample collection, concentration and selectivity; and novel long-range methods for example environmental changes.

Author(s): Joanna Ingraham, Justin McIntyre

New tiltmeter developed in Institute of Physics of the Earth of the Russian Academy of Sciences

Engineering Sciences and Technology Journal (ESTJ), Volume 2, Jan 2017

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A tiltmeter has been developed at the Institute of Physics of the Earth of the Russian Academy of Sciences as the regular equipment for geophysical observatories and other observation posts. The tiltmeter is intended for relative measurement of tilts of a terrestrial surface in two mutually perpendicular directions for the purpose of studying tidal deformations, research of modern earth movements, research of harbingers of earthquakes in the form of abnormal inclinations, and also deformations of the bases and parts of large engineering constructions. The tiltmeter which has been developed possesses record-breaking high precision 0.0001 arc sec. in a range of measurement +/-2 arc sec.; thus it has extremely high long-term tool stability (tool drift of "zero" no more +/-1 arc sec. per year). The combination of these major technical characteristics makes this tiltmeter an outstanding achievement in the field of geophysical instrument making. Sensor action is based on the principle of a vertical pendulum. In the sensor design a metal pendulum (length about 100 mm) is suspended on an elastic suspension over the ceramic part fixed on the case. The pendulum has a natural period of 0.6 seconds and air damping. It is isolated from the case and together with a ceramic part forms the differential two coordinate measuring condenser. On a ceramic casing four metal plates serving as facings of the measuring condenser are fixed. At an inclination of the sensor case the pendulum moves with respect to the condenser facings proportionally, making an inclination from these axes. As a result the measuring condenser records signals proportional to the angle of slope of the sensor on its sensitivity axes ?N-S? and ?E-W?.

Author(s): Sergey Matcievsky, Igor Vasilev, Valentin Gravirov

EVALUATION OF TRACK GEOMETRY STANDARDS BY NUMERICAL SIMULATIONS PROPOSAL FOR EVOLUTIONS

Engineering Sciences and Technology Journal (ESTJ), Volume 2, Jan 2017

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Abstract
Track geometry standards have been enforced for more than ten years in the French Railway Network. Limit values were derived from experience, and up to now they remain a good guarantee of train running safety. The very high speed intensive commercial circulation (V > 300kph) on long distance on high-speed lines as well as the advent of new types of vehicle could require determining limit values adapted to these new conditions. The study consists of using vehicle simulation software for evaluating the consistency between the current track geometry standards and the safety criteria for vehicle acceptance. The possibility of using such software for determining track geometry standards has also been investigated. The influence of track defects on the behaviour of a TGV, running at different speeds and in various conditions, has been analysed for different criteria of defects such as amplitude, wavelength and shape. The study shows that current track geometry standards appropriately cover the studied cases in spite of results close to the limit for very-short-length defects. Moreover, defect wavelength and shape both seem to be important factors in vehicle dynamics. This study has also helped to define a new method to update track geometry standards (V > 22 0kph) and to explore needs for a new very high-speed standard (V > 300kph).

Author(s): V Bourgoin, F Coudert

ANALYSIS OF CHARACTERISTICS OF POWER SPECTRAL DENSITY (PSD) OF TRACK IRREGULARITY ON THE EXISTING RAILWAY LINES

Engineering Sciences and Technology Journal (ESTJ), Volume 2, Jan 2017

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To improve the calculation accuracy of PSD of track irregularities, an elimination method of outliers and a zero mean normalization method of track irregularities are given and used in the data preprocessing of track irregularities on the existing railway lines. The elimination method of outliers is based on the change rate of track irregularities and the method of linear interpolation, and the method of wavelet analysis is used for the zero mean normalization method of track irregularities. After the preprocessing of track irregularities, the PSD of track irregularities of the existing railway lines is calculated by using the FFT method. The statistic and analysis result indicates that the PSD of track irregularities of the existing railway lines obeys a chi-square contribution with 2 degrees of freedom and can be described by using the median of PSD. The PSD of track irregularities of three different speed classes of the existing railway lines is calculated and compared. The PSD of track irregularities can characterize the track status, The PSD of track irregularities of the 2 50km/h speed lines is lower than The PSD of track irregularities of the 2 00km/h and 1 60km/h speed lines.

Author(s): XB Liu, DS Chen, WD Wang

Proxy-based sea ice reconstructions for two Arctic locations with similar latitudes yet highly contrasting oceanographic and environmental settings

Engineering Sciences and Technology Journal (ESTJ), Volume 2, Sep 2017

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The presence of the sea ice diatom biomarker IP25 in Arctic marine sediments has been used in previous studies as a proxy for past spring sea ice occurrence and as an indicator of wider palaeoenvironmental conditions for different regions of the Arctic over various timescales. The current study will (1) briefly describe the sea ice conditions of northern Norway for the interval ca 13.8 - 7.2 cal ka BP and (2) mainly focus on a different study around the East Greenland-North Iceland area (Denmark Strait), during the ca last 140 yr. The Denmark Strait area is a critical region due to the interaction between the polar and subpolar climate systems. On the Greenland side of the strait the conditions are severe with a 8 ? 10 month sea ice cover, with numerous tidewater glacier margins injecting icebergs into the fjords and adjacent shelf. Unexpectedly, abundances of marine biomarkers such as IP25 were remarkably low compared to other Arctic regions (e.g. Canadian Arctic, Fram Strait) that also experience severe sea ice conditions. A possible theory for explaining such a scenario will be presented, together with mineralogical data (e.g. ice rafted debris (IRD), quartz/feldspar hematite stained grains (HSG)) as well as observational data (e.g. storis) acquired during this period.

Author(s): Patricia Cabedo-Sanz, Simon Belt, J. Knies, K. Husum, J. Andrews,M. Alonso-Garcia, D. Darby and J. Jaeger

Recent Geological Understanding of the Chicontepec Erosional ?Paleocanyon,? Tampico-Misantla Basin, Mexico

Engineering Sciences and Technology Journal (ESTJ), Volume 2, Aug 2017

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The Chicontepec Formation in eastern central Mexico has long been explored for its oil accumulations and contains several large unconformities, which in the past seem to have been miscorrelated across the Tampico-Misantla Basin. The formation is of current interest because it may help us to understand the mechanisms of delivery of the Wilcox sands in the deep Gulf of Mexico. In the northern part of the Chicontepec play, outcrop data indicate that a major unconformity occurs at about 55 Ma (i.e., the Paleocene/Eocene boundary). Outcrops overlying this unconformity show a ?classic? section about 150 meters thick; mass transport complexes on top of the unconformity are in turn overlain by sheet sandstones, channels, and channel levee complexes. In the central part of the play, there is a major unconformity in the Eocene, between 47 and 53 Ma (probably late early Eocene). In the southern part of the play (in the Agua Fria Field area) the first major erosional unconformity is between 43.6 and 50.4 Ma. In the extreme southern part of the play, in the Presidente Aleman area, the oldest unconformity is at approximately 40 Ma. The unconformities all have been generated in submarine environments. Without the benefit of seismic and high-resolution biostratigraphic data, earlier workers miscorrelated these unconformities and assumed that they were one large unconformity, forming the Chicontepec ?paleocanyon.? All the unconformities are regional events and occur throughout the basin. The 43.6 to 50.4 Ma erosional event (unconformity A) is a correlatable seismic event across a large proportion of the Tampico-Misantla Basin. This event has been cored in at least two wells. In the closest well to the canyon, a 110 meter thick mass transport deposit immediately overlies the unconformity. The mass transport deposit consists of a basal 30-meter pebbly mudstone debrite, overlain by an 80 meter thick slump. Recent interpretation in the Agua Fria, Tajin and Coapechaca (ATC) fields, west of Poza Rica, Veracruz, has allowed more detailed mapping of the erosional unconformities and a better estimate of the volume of material removed at unconformity A. In this area, the feature is up to 6 km wide and, in some places more than 600 meters of consolidated Paleocene and Cretaceous strata have been removed. Production from the ATC fields west of Poza Rica, is from the infill of the ?paleocanyon? (canyon-fill trap) and the pre-erosion strata (canyon truncation trap), and the trapping mechanism is both stratigraphic and diagenetic in nature.

Author(s): Cossey, Stephen P.J.

THE U-SHAPED VIADUCT AND ITS APPLICATION TO THE DUBAI METRO

Engineering Sciences and Technology Journal (ESTJ), Volume 2, Feb 2017

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There are 62km of viaducts along the 74km of red and green lines that make up the Metro of Dubai. This project is a major undertaking which incorporates a viaduct design - the U-shaped viaduct - developed specially by SYSTRA for this type of project. We are therefore going firstly to describe this concept, chronicle its development and see how it has been applied in Dubai.

Author(s): Daniel Dutoit, Serge Montens

DAMAGE OF THE MAIN CITY SEWER AFTER HALF CENTURY OF SERVICE LIFE AND REPAIR POSSIBILITIES

Engineering Sciences and Technology Journal (ESTJ), Volume 2, Aug 2017

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After few decades of exploitation and exposition to the aggressive influence of waste water, on the inner surfaces of main RC sewer in Novi Sad severe damages appeared. Assessment procedure of reinforced concrete sewer which was built in sixties of the past century is shown in the paper. It is concluded that characteristic damages of walls and upper slab from the inner side are: concrete corrosion, erosion of the surface concrete layer, reinforcement corrosion and disturbed bond between reinforcement and concrete. On the basis of performed analyze of registered damages and results of testing of reinforcement and concrete samples, it was concluded that functionality of the sewer is reduced and the durability is decreased. The bearing capacity is reduced and stability of the structure is jeopardized due to the strong corrosion of the reinforcement in the upper slab, also. Due to lack of project documentation control calculation was done, whereby the sewer structure was treated as a frame system directly relied on the ground. Static influences were calculated for vertical and horizontal load of soil, ground water pressure at maximum level and traffic load of heavy vehicles V-600. Two possible scenarios were considered: rehabilitation of the existing sewer with dimensions of 2 00/140 cm and demolition of the existing and construction of new collector with a larger size 3 00/170 cm. Rehabilitation solution included the repair and strengthening of the walls and a complete replacement of the upper slab. Due to the limited space to perform repair work techno-economic analysis was done. Repair cost and cost of the new sewer construction, including durability and their capacity, were compared.

Author(s): MMalesev, V Radonjanin

Government initiatives and international cooperation in seismology providing knowledge and

Engineering Sciences and Technology Journal (ESTJ), Volume 2, Feb 2017

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Abstract
The Geological Survey of Namibia established a National Seismological Network in 2000 which has expanded to seven seismological stations to date, with a view to improve seismological records and ultimately generate a Seismic Hazard Map of the country. As a signatory of the Comprehensive Nuclear-Test- Ban Treaty (CTBT), the government in cooperation with CTBTO established an International Monitoring Station (IMS) in Tsumeb which monitors nuclear explosions worldwide. Collaborative projects include researches in Geosciences and weather studies with AfricaArray, with the main objective of studying the crustal studies. Walvis Bay Ridge Passive Source and Active Seismic Experiments with German Research Centre for Geoscience (GFZ) wwith a view of understanding the roll of the plume-lithosphere interaction during break-up of the Southern Atlantic Ocean and lithospheric structure of the passive volcanic margin of Namibia. More recently, seismology in schools project in collaboration with the British Geological Survey has been started, with a primary object of encouraging learners to take science as career.

Author(s): Bufelo Lushetile, Dave Hutchins

RETROFITTING OF SHORTTO- MEDIUM-SPAN CONCRETE BRIDGES AFTER STRONG INTENSITY EARTHQUAKES

Engineering Sciences and Technology Journal (ESTJ), Volume 2, Feb 2017

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Bridges which were built before 1 970s, either in the US or Japan or Europe, had been designed with little or no consideration for seismic demand. Majority of these bridges are supported by reinforced concrete bents and pier walls that lack the ductility and strength to resist earthquakes. Meanwhile strong motion earthquakes have revealed all vulnerable places on each of those bridges if built in seismically active region. After the 1 971 San Fernando earthquake the US started several seismic retrofit programs. Retrofit programs in the 1 980s included the first use of isolators on bridges and a program to retrofit single-column bents. These programs were greatly accelerated after the 1 989 Santa Cruz (Loma Prieta) and 1 994 Northridge earthquakes. After the 1 994 Northridge earthquake it was observed that no serious damage would have occurred if the previous retrofit program had already been implemented. Japan also started similar programs, especially after the 1 995 Kobe earthquake. Europe may not be out of this global problem and must have own retrofit program not only for buildings (Eurocode 8, Part 3 : Assessment and retrofitting of buildings, EN 1 998-3:2005) but for bridges as well. Some solutions for retrofitting the abutment, bent and column of concrete bridges recommended in these programs as well as some recommendations and comments made by the author will be presented in this paper.

Author(s): M Causevic