394 research outputs found

    Development of a microprocessor-based biochemical sampler

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    Modern medicine requires patients to be treated on the basis of precise data, which are often obtained from electronic equipment. An inexpensive and portable microprocessor-based sampler developed by the authors is described. It is comprised of the following units: sample plate assembly, probe-drive linkage system, wash fluid receptacle, timing system and 8085A microprocessor

    Development of a heating reactor for a continuous flow-through application in urea measurement

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    In most biochemical analyses, a flow-through heating arrangement is needed to reduce the reaction time or maintain a constant temperature. A rectangular reactor is described that is constructed of aluminium, is hollow inside and is filled with silicone oil. The glass coil through which the solution flows is immersed in the silicone oil. The heater, a Peltier-effect heat pump, on one side and the temperature sensor on the other side of the reactor body are embedded for heating and temperature control. The brief performance evaluation of the reactor is discussed by measuring the absorbance of urea concentration at different temperatures

    Identifying salt marsh shorelines from remotely sensed elevation data and imagery

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    © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Farris, A. S., Defne, Z., & Ganju, N. K. Identifying salt marsh shorelines from remotely sensed elevation data and imagery. Remote Sensing, 11(15), (2019): 1795, doi: 10.3390/rs11151795.Salt marshes are valuable ecosystems that are vulnerable to lateral erosion, submergence, and internal disintegration due to sea level rise, storms, and sediment deficits. Because many salt marshes are losing area in response to these factors, it is important to monitor their lateral extent at high resolution over multiple timescales. In this study we describe two methods to calculate the location of the salt marsh shoreline. The marsh edge from elevation data (MEED) method uses remotely sensed elevation data to calculate an objective proxy for the shoreline of a salt marsh. This proxy is the abrupt change in elevation that usually characterizes the seaward edge of a salt marsh, designated the “marsh scarp.” It is detected as the maximum slope along a cross-shore transect between mean high water and mean tide level. The method was tested using lidar topobathymetric and photogrammetric elevation data from Massachusetts, USA. The other method to calculate the salt marsh shoreline is the marsh edge by image processing (MEIP) method which finds the unvegetated/vegetated line. This method applies image classification techniques to multispectral imagery and elevation datasets for edge detection. The method was tested using aerial imagery and coastal elevation data from the Plum Island Estuary in Massachusetts, USA. Both methods calculate a line that closely follows the edge of vegetation seen in imagery. The two methods were compared to each other using high resolution unmanned aircraft systems (UAS) data, and to a heads-up digitized shoreline. The root-mean-square deviation was 0.6 meters between the two methods, and less than 0.43 meters from the digitized shoreline. The MEIP method was also applied to a lower resolution dataset to investigate the effect of horizontal resolution on the results. Both methods provide an accurate, efficient, and objective way to track salt marsh shorelines with spatially intensive data over large spatial scales, which is necessary to evaluate geomorphic change and wetland vulnerability.This project was supported by the U.S. Geological Survey (USGS) Coastal/Marine Natural Hazards and Resources Program as well as the Massachusetts O ce of Coastal Zone Management under interagency agreement 16ENMALQ006000

    Resolving the predicament of android custom permissions

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    Android leverages a set of system permissions to protect platform resources. At the same time, it allows untrusted third-party applications to declare their own custom permissions to regulate access to app components. However, Android treats custom permissions the same way as system permissions even though they are declared by entities of different trust levels. In this work, we describe two new classes of vulnerabilities that arise from the ‘predicament’ created by mixing system and custom permissions in Android. These have been acknowledged as serious security flaws by Google and we demonstrate how they can be exploited in practice to gain unauthorized access to platform resources and to compromise popular Android apps. To address the shortcomings of the system, we propose a new modular design called Cusper for the Android permission model. Cusper separates the management of system and custom permissions and introduces a backward-compatible naming convention for custom permissions to prevent custom permission spoofing. We validate the correctness of Cusper by 1) introducing the first formal model of Android runtime permissions, 2) extending it to describe Cusper, and 3) formally showing that key security properties that can be violated in the current permission model are always satisfied in Cusper. To demonstrate Cusper’s practicality, we implemented it in the Android platform and showed that it is both effective and efficient

    Development of a submerged aquatic vegetation growth model in the coupled ocean-atmosphere-wave-sediment transport (COAWST v3.4) model

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    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Kalra, T. S., Ganju, N. K., & Testa, J. M. Development of a submerged aquatic vegetation growth model in the coupled ocean-atmosphere-wave-sediment transport (COAWST v3.4) model. Geoscientific Model Development, 13(11), (2020): 5211-5228, doi:10.5194/gmd-13-5211-2020.The coupled biophysical interactions between submerged aquatic vegetation (SAV), hydrodynamics (currents and waves), sediment dynamics, and nutrient cycling have long been of interest in estuarine environments. Recent observational studies have addressed feedbacks between SAV meadows and their role in modifying current velocity, sedimentation, and nutrient cycling. To represent these dynamic processes in a numerical model, the presence of SAV and its effect on hydrodynamics (currents and waves) and sediment dynamics was incorporated into the open-source Coupled Ocean–Atmosphere–Wave–Sediment Transport (COAWST) model. In this study, we extend the COAWST modeling framework to account for dynamic changes of SAV and associated epiphyte biomass. Modeled SAV biomass is represented as a function of temperature, light, and nutrient availability. The modeled SAV community exchanges nutrients, detritus, dissolved inorganic carbon, and dissolved oxygen with the water-column biogeochemistry model. The dynamic simulation of SAV biomass allows the plants to both respond to and cause changes in the water column and sediment bed properties, hydrodynamics, and sediment transport (i.e., a two-way feedback). We demonstrate the behavior of these modeled processes through application to an idealized domain and then apply the model to a eutrophic harbor where SAV dieback is a result of anthropogenic nitrate loading and eutrophication. These cases demonstrate an advance in the deterministic modeling of coupled biophysical processes and will further our understanding of future ecosystem change.This is University of Maryland Center for Environmental Contribution no. 5909

    Development of a coupled wave-flow-vegetation interaction model

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    © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Computers & Geosciences 100 (2017): 76–86, doi:10.1016/j.cageo.2016.12.010.Emergent and submerged vegetation can significantly affect coastal hydrodynamics. However, most deterministic numerical models do not take into account their influence on currents, waves, and turbulence. In this paper, we describe the implementation of a wave-flow-vegetation module into a Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modeling system that includes a flow model (ROMS) and a wave model (SWAN), and illustrate various interacting processes using an idealized shallow basin application. The flow model has been modified to include plant posture-dependent three-dimensional drag, in-canopy wave-induced streaming, and production of turbulent kinetic energy and enstrophy to parameterize vertical mixing. The coupling framework has been updated to exchange vegetation-related variables between the flow model and the wave model to account for wave energy dissipation due to vegetation. This study i) demonstrates the validity of the plant posture-dependent drag parameterization against field measurements, ii) shows that the model is capable of reproducing the mean and turbulent flow field in the presence of vegetation as compared to various laboratory experiments, iii) provides insight into the flow-vegetation interaction through an analysis of the terms in the momentum balance, iv) describes the influence of a submerged vegetation patch on tidal currents and waves separately and combined, and v) proposes future directions for research and development.This study was part of the Estuarine Physical Response to Storms project (GS2-2D), supported by the Department of Interior Hurricane Sandy Recovery program

    Development of a photometric system for continuous flow analysis

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    Most chemical analyses carried out in a clinical laboratory are colorimetric. An improved photometric system is described where a tungsten lamp is the light source, a photo-diode is the detector and a microcontroller 8051 is used for processing and displaying absorbances. The performance characteristics of the instrument are reported. The parameters investigated are photometric linearity, precision and instrumental drift

    Wildlife Collisions to Aircraft in India

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    Wildlife strikes (mainly birds, but also includes bats and other mammals on the ground) with aircraft isa serious economic and safety concern in the aviation industry. The solution to the problem can be evolved byidentifying the species involved in the incidents/ accidents. In the Indian context, such an attempt was started in1980. In the recent past, the Indian Air Force adopted the DNA Bar-coding technology to identify the species involved. The extent of the problems faced by the country and involvement of different species in various time blocks has been compared with the objective of analyzing changes over different periods to gauge the changes and assess the future requirements. The data indicates that over the years, the number of strikes has increased manifold in the civil aviation sector. The number of species involved in strikes has almost doubled. The serious strikes due to Vultures have nearly disappeared and their place has been mainly taken over by Black Kites. In the recent past, Black Kites are the cause of the highest damages and also have the highest probability of causing damages (61.17%) when struck. Adoption of DNA Barcoding technology has helped to identify the species in incidents where minimal bird remnants were found. Although the number of accidents has decreased, the economical losses continue to rise due to the high cost of modern aircraft

    Forced Sexual Relations Among Young Women in Developing Countries

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    Recent research in developing countries suggests that a considerable number of young women may experience forced sex within marriage, but most women may be inhibited from reporting these experiences due to shame, fear of reprisal or deep-rooted unequal gender norms.The consequences of domestic violence can be severe, and in fact, intimate partner violence is one of the leading causes of death among women 15-44 years of age.(1) Papers highlighting the nature and prevalence of coercion among married young women were presented at a global consultative meeting in New Delhi.Evidence comes from small-scale studies and large population-based surveys, such as Demographic and Health Surveys (DHS), from some developing countries. Many women may under report coercion by a partner within marriage, and there are variations in the framing of questions posed, methods of data collection and the reference period, making findings of small-scale studies difficult to compare. However, available data give an idea of the extent and nature of coercion that married young women experience. Studies reveal that sexual coercion within marriage includes deception, verbal threats or psychological intimidation to obtain sex, attempted rape and forced penetrative sex.(2)Forced marital sex can be accompanied by physical or emotional violence. Sexual coercion is observed in marital partnerships in diverse settings such as South Asia, Latin America, Africa and the Middle East. Although cultural settings and contexts condition the nature of coercion among married young women, there are striking similarities across different settings

    Evolution of Mid-Atlantic coastal and back-barrier estuary environments in response to a hurricane : implications for barrier-estuary connectivity

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    This paper is not subject to U.S. copyright. The definitive version was published in Estuaries and Coasts 39 (2016): 916-934, doi:10.1007/s12237-015-0057-x.Assessments of coupled barrier island-estuary storm response are rare. Hurricane Sandy made landfall during an investigation in Barnegat Bay-Little Egg Harbor estuary that included water quality monitoring, geomorphologic characterization, and numerical modeling; this provided an opportunity to characterize the storm response of the barrier island-estuary system. Barrier island morphologic response was characterized by significant changes in shoreline position, dune elevation, and beach volume; morphologic changes within the estuary were less dramatic with a net gain of only 200,000 m3 of sediment. When observed, estuarine deposition was adjacent to the back-barrier shoreline or collocated with maximum estuary depths. Estuarine sedimentologic changes correlated well with bed shear stresses derived from numerically simulated storm conditions, suggesting that change is linked to winnowing from elevated storm-related wave-current interactions rather than deposition. Rapid storm-related changes in estuarine water level, turbidity, and salinity were coincident with minima in island and estuarine widths, which may have influenced the location of two barrier island breaches. Barrier-estuary connectivity, or the transport of sediment from barrier island to estuary, was influenced by barrier island land use and width. Coupled assessments like this one provide critical information about storm-related coastal and estuarine sediment transport that may not be evident from investigations that consider only one component of the coastal system.Funding for this project was provided by the New Jersey Department of Environmental Protection and the US Geological Survey (USGS) Coastal and Marine Geology Program
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