1,165 research outputs found

    Transport and biodegradation of volatile organic compounds : influence on vapor intrusion into buildings

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    Vapor intrusion occurs when volatile subsurface contaminants, migrating from the saturated zone through the unsaturated zone, accumulate in buildings. It is often the most relevant pathway for human health risks at contaminated sites, especially in urban areas; yet its assessment is controversial. Field assessment of vapor intrusion risk is complicated by two interrelated main factors that are controlled by the contaminant’s properties: transport processes in the unsaturated zone and biodegradation in the unsaturated zone. Commonly available vapor intrusion models either overlook significant properties at the field scale or, conversely, are too complex to be applicable at this scale. Specifically, moisture variation, liquid diffusion, dynamic processes such as water table variations, and biodegradation are not adequately accounted for. As a result, the soil gas and indoor air concentrations predicted by existing models frequently overestimate measured concentrations by several orders of magnitude. This thesis addressed transport and biodegradation processes of volatile organic compounds, focusing on aerobic unsaturated zones. The main aims were to i) characterize significant transport processes influencing vapor intrusion and ii) quantify and mechanistically describe biodegradation in unsaturated soils. Field experience, numerical modeling and laboratory experiments with toluene and vinyl chloride as reference compounds were combined to separate out the relevant processes influencing vapor intrusion. The main conclusions from this thesis indicate that soil moisture variations and aerobic biodegradation are crucial aspects to be jointly considered for the assessment of vapor intrusion. These may contribute to a significant reduction in the risk associated with dissolved volatile organic contaminants. Specific and relevant implications for modeling and monitoring vapor intrusion can be derived. With respect to vapor intrusion modeling, when including unsaturated zone biodegradation, the use of liquid phase biodegradation rates as derived from liquid mixed batches may underestimate by several orders of magnitude the liquid degradation rates in the unsaturated system. Therefore, biodegradation rates derived from unsaturated system appear more appropriate. With respect to monitoring, vertical soil moisture variations and contaminant/oxygen concentration profiles need to be measured in the field, in order to account for the above processes. </p

    Low molecular weight ϵ-caprolactone-pcoumaric acid copolymers as potential biomaterials for skin regeneration applications

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    ϵ-caprolactone-p-coumaric acid copolymers at different mole ratios (ϵ-caprolactone:p-coumaric acid 1:0, 10:1, 8:1, 6:1, 4:1, and 2:1) were synthesized by melt-polycondensation and using 4-dodecylbenzene sulfonic acid as catalyst. Chemical analysis by NMR and GPC showed that copolyesters were formed with decreasing molecular weight as p-coumaric acid content was increased. Physical characteristics, such as thermal and mechanical properties, as well as water uptake and water permeability, depended on the mole fraction of pcoumaric acid. The p-coumarate repetitive units increased the antioxidant capacity of the copolymers, showing antibacterial activity against the common pathogen Escherichia coli. In addition, all the synthesized copolyesters, except the one with the highest concentration of the phenolic acid, were cytocompatible and hemocompatible, thus becoming potentially useful for skin regeneration applications

    Has the European Union Achieved a Single Pharmaceutical Market?

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    This paper explores price differences in the European Union (EU) pharmaceutical market, the EU's fifth largest industry. With the aim of enhancing quality of life along with industry competitiveness and R&D capability, many EU directives have been adopted to achieve a single EU-wide pharmaceutical market. Using annual 1994–2003 data on prices of molecules that treat cardiovascular disease, we examine whether drug price dispersion has indeed decreased across five EU countries. Hedonic regressions show that over time, cross-country price differences between Germany and three of the four other EU sample countries, France, Italy and Spain, have declined, with relative prices in all three as well as the fourth country, UK, rising during the period. We interpret this as evidence that the EU has come closer to achieving a single pharmaceutical market in response to increasing European Commission coordination efforts.

    The 20 GHz solid state transmitter design, impatt diode development and reliability assessment

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    A single drift gallium arsenide (GaAs) Schottky barrier IMPATT diode and related components were developed. The IMPATT diode reliability was assessed. A proof of concept solid state transmitter design and a technology assessment study were performed. The transmitter design utilizes technology which, upon implementation, will demonstrate readiness for development of a POC model within the 1982 time frame and will provide an information base for flight hardware capable of deployment in a 1985 to 1990 demonstrational 30/20 GHz satellite communication system. Life test data for Schottky barrier GaAs diodes and grown junction GaAs diodes are described. The results demonstrate the viability of GaAs IMPATTs as high performance, reliable RF power sources which, based on the recommendation made herein, will surpass device reliability requirements consistent with a ten year spaceborne solid state power amplifier mission

    All That is Possible Can Be Imagined: Leibniz's "Von der Allmacht"

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    Leibniz's 'Von der Allmacht and Allwissenheit Gottes and der Freiheit des Mensched is obscure and misunderstood. First I do a close reading of the work. Then I will discuss some scholarly interpretations, as well as VdA's place in Leibniz's thought. I challenge two scholarly assumptions--the first being that Leibniz rejected then accepted privation theory. I argue that there are two types of privation theories, using illustrative historical examples, and that Leibniz objected to one and adopted the other. Secondly, many scholars opine that the Confessio is a juvenile Theodicy. I take VdA to be an important predecessor to the Theodicy due to similarities in style, content and method. Finally, I link Leibniz's definition of possibility in VdA with an important connection between truth and existence. In this respect, Leibniz's ideas of possibility and conceivability are the forerunners of a current topic in philosophy

    A sidecar object for the optimized communication between edge and cloud in internet of things applications

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    The internet of things (IoT) is one of the most disrupting revolutions that is characterizing the technology ecosystem. In the near future, the IoT will have a significant impact on people's lives and on the design and developments of new paradigms and architectures coping with a completely new set of challenges and service categories. The IoT can be described as an ecosystem where a massive number of constrained devices (denoted as smart objects) will be deployed and connected to cooperate for multiple purposes, such a data collection, actuation, and interaction with people. In order to meet the specific requirements, IoT services may be deployed leveraging a hybrid architecture that will involve services deployed on the edge and the cloud. In this context, one of the challenges is to create an infrastructure of objects and microservices operating between both the edge and in the cloud that can be easily updated and extended with new features and functionalities without the need of updating or re-deploying smart objects. This work introduces a new concept for extending smart objects' support for cloud services, denoted as a sidecar object. A sidecar object serves the purpose of being deployed as additional component of a preexisting object without interfering with the mechanisms and behaviors that have already been implemented. In particular, the sidecar object implementation developed in this work focuses on the communication with existing IoT cloud services (namely, AWS IoT and Google Cloud IoT) to provide a transparent and seamless synchronization of data, states, and commands between the object on the edge and the cloud. The proposed sidecar object implementation has been extensively evaluated through a detailed set of tests, in order to analyze the performances and behaviors in real- world scenarios

    ZWT: A new cross-platform graphical interface framework for Java applications

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    The Java Programming Language revolutionized the world of software development in the last decades. Thanks to its portability, Java makes it possible to develop software that can run everywhere, in a truly cross-platform computing environment. Although running the same Java code anywhere works smoothly on major desktop and server platforms, this becomes much more complicated when different devices and platforms, such as smartphones or embedded systems, are taken into account. Furthermore, even if we consider devices that natively support the Java programming language, the same application may not run without re-writing part or the entire source code. This is mainly due to the existence of platform specific libraries for accessing input/output peripherals or system-specific features. In particular, the main limitation is usually associated to the different APIs that must be used for programming the Graphical User Interface (GUIs). In this paper, we present a novel framework that can be used by developers to write Java applications with portable GUIs that are truly platform-independent and thus can run on different systems such as PCs, Workstations, Android devices or mobile phones and embedded systems with Java MicroEdition (Java ME)

    Hyaline fibromatosis syndrome (juvenile hyaline fibromatosis): whole-body MR findings in two siblings with different subcutaneous nodules distribution

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    Abstract: Hyaline fibromatosis syndrome (juvenile hyaline fibromatosis) is a rare, progressive, autosomal recessive disorder whose main hallmark is the deposition of amorphous hyaline material in soft tissues, with an evolutionary course and health impairment. It may present involvement of subcutaneous or periskeletal soft tissue, or may develop as a visceral infiltration entity with poor prognosis. Very few radiological data about this inherited condition have been reported, due to the extreme rarity of disease. We herein present a case of two siblings, affected by different severity of the disease, with different clinical features. They were examined by whole-body MR (WBMR) in order to assess different lesions localization, to rule out any visceral involvement and any other associated anomalies and to define patients\ue2\u80\u99 management

    The role of initial conditions in the ageing of the long-range spherical model

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    The kinetics of the long-range spherical model evolving from various initial states is studied. In particular, the large-time auto-correlation and -response functions are obtained, for classes of long-range correlated initial states, and for magnetized initial states. The ageing exponents can depend on certain qualitative features of initial states. We explicitly find the conditions for the system to cross over from ageing classes that depend on initial conditions to those that do not.Comment: 15 pages; corrected some typo

    MR Imaging of Perianal Crohn Disease: The Role of Contrast-enhanced Sequences

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    The MR imaging protocol described by the authors includes contrast-enhanced T1-weighted imaging with fat saturation in all patients except those with poor renal function. Horsthuis et al demonstrated in 2009 the usefulness of contrast-enhanced MR imaging for determining disease activity. Contrast agent administration is also required in case of suspicion of neoplastic tissue complicating fistulas. The joint European Crohn\u2019s and Colitis Organisation\u2013European Society of Gastointestinal and Abdominal Radiology guidelines report that T2-weighted images and contrast-enhanced T1-weighted images are included in the MR imaging protocol for the evaluation of perianal CD. However, as we have demonstrated, an axial T2-weighted fast spinecho sequence with fat saturation, in particular the short inversion time inversion-recovery (STIR) sequence, is a valid alternative to postcontrast T1- weighted fat-saturated imaging, allowing the identification of the primary fistula and any secondary ramification
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