Palaeoenvironmental Conditions of the Mavropigi Lignites,Ptolemais Basin,Greece: A Petrological Study

The aim of this study is to interpret the palaeoenvironmental conditions established during the formation of several lignite seams at the Mavropigi deposit, Ptolemais, Greece (corehole MAK-48). In nine representative lignite samples, ash contents, as well as the contents of the elements C, H, N, O, and S were determined. Polished block sections from the same samples were examined under the microscope. The ash contents (750°C) of the studied lignite seams range between 10–29% (on dry basis). The contents of C, H, N, and O display values between 36–55%, 2.4–4.6%, 0.7–2%, and 21–37.5%, respectively, while S contents do not exceed 1.4%. Huminite is the prevailing maceral group (87–95%). All the samples, except No. 35, display a distinct prevalence in detrohuminite maceral subgroup (up to 69 vol%, mmf). Liptinite and inertinite maceral groups show low contents, which do not exceed 9% and 7%, respectively. The Mavropigi lignites are medium to low grade coals and can be regarded as peat to lignite in terms of thermal maturity. The studied lignite seams formed in fens, possibly from herbaceous plants under limnotelmatic regime. During peat deposition, conditions were very moist and intense reducing with increased bacterial activity. The ratio of plant growth and peat accumulation versus rise of water table due to the subsidence rate was not well balanced. As a result, the petrographical composition of the Mavropigi lignites is related either to a long residence time of the organic matter in the acrotelm or to a herbaceous vegetation origin.     

Specifying and verifying usage control models and policies in TLA $$^+$$ +

International Journal on Software Tools for Technology Transfer - Novel computing paradigms, e.g., the Cloud, introduce new requirements with regard to access control such as utilization of...     

Formal methods and tools for industrial critical systems

International Journal on Software Tools for Technology Transfer - Formal methods and tools have become well established and widely applied to ensure the correctness of fundamental components of...     

Petrographic Characteristics of the Kardia Lignites (Core KT6A-3), Ptolemais Basin (Greece)

The aim of this study is to provide useful coal-petrographic data, which will further help the characterization, exploitation, and utilization of the Kardia lignite deposit and also initially to access the depositional conditions mainly in terms of water table level and subsidence rate of the fen substrate. Ash contents, as well as the C, H, N, O, and S were determined in nine lignite samples from core KT6A-3. The ash contents (750°C) of the studied lignite seams range among 14–37% (on dry basis). Contents of C, H, N, and O have values between 34–52%, 2.5–4.2%, 0.8–2%, and 21–30.6%, respectively. Sulfur does not exceed 1.2%. Huminite group dominates with values between 84–99 vol%, mmf. All samples display a distinct prevalence in detrohuminite (up to 82 vol%) with attrinite being most abundant. Liptinite and inertinite macerals have low contents, which do not exceed 8% and 12%, respectively. The Kardia lignites are medium to very low-grade coals. They formed in fens under limnotelmatic regime and originated from herbaceous vegetation. During peat deposition, conditions were well moist, intense reducing, and favored increased bacterial activity. The ratio of plant growth and peat accumulation versus rise of water table due to the subsidence rate was not well balanced. The petrographical composition of the Kardia lignites is related either to a long residence time of the organic matter in the acrotelm or to an herbaceous vegetation origin.     

Comparative design study of a diesel exhaust gas heat exchanger for truck applications with conventional and state of the art heat transfer enhancements

The exhaust gas of heavy duty diesel engines can provide an important heat source that may be used in a number of ways to provide additional power and improve overall engine efficiency. The sizing of a heat exchanger that can manage the heat load and still be of reasonable size and weight without excessive pressure drop is of significant importance especially for truck applications. This is the subject of the present work. To approach the problem, a total of five different configurations are investigated and a comparison of conventional and state of the art heat transfer enhancement technologies is included. Two groups of configurations are examined: (a) a classical shell and tube heat exchanger using staggered cross-flow tube bundles with smooth circular tubes, finned tubes and tubes with dimpled surfaces and (b) a cross-flow plate heat exchanger, initially with finned surfaces on the exhaust gas side and then with 10 ppi and 40 ppi metal foam material substituting for the fins. Calculations were performed, using established heat exchanger design methodologies and recently published data from the literature to size the aforementioned configurations. The solutions provided reduce the overall heat exchanger size, with the plate and fin type consisting of plain fins presenting the minimum pressure drop (up to 98% reduction compared to the other configurations), and the 40 ppi metal foam being the most compact in terms of size and weight. Durability of the solutions is another issue which will be examined in a future investigation. However, coupling of the exhaust heat exchanger after a particulate trap appears to be the most promising solution to avoid clogging from soot accumulation.     

Improvement of chloride ion penetration resistance in cement mortars modified with rubber from worn automobile tires

Disposal of worn tires poses a major problem worldwide. In Greece more than 50,000 tons of worn automobile tires are stockpiled annually. This paper presents the results of laboratory research that examines the incorporation of tire rubber granules as a partial replacement for the sand in cement mortars. Physical and mechanical properties of these rubber mixtures are studied while, for the first time, resistance to chloride ion penetration is measured.Results showed a decrease in mechanical properties, whereas an increase in chloride ion penetration resistance has been observed. This implies that cement-based mortar and concrete products, modified with tire rubber granules as a partial replacement for the sand, can be used in applications where mechanical properties are not of prime importance but where high resistance to chloride ion penetration is demanded.     

Mining affective needs of automotive industry customers for building a mass-customization recommender system

Mass customization systems aim to receive customer preferences in order to facilitate personalization of products and services. Current online configuration systems are unable to efficiently identify real customer affective needs because they offer an excess variety of products that usually confuse customers. On the other hand, mining affective customer needs may result in recommender systems, which can enhance existing configuration systems by recommending initial configurations according to customer affective needs. This paper introduces a mass customization recommender system that exploits data mining techniques on automotive industry customer data aiming at revealing associations between user affective needs and the design parameters of automotive products. One key novelty of the presented approach is that it deploys the Citarasa engineering, a methodology that focuses on the provision of the appropriate characterizations on customer data in order to associate them with customer affective needs. Based on the application of classification techniques we build a recommendation engine, which is evaluated in terms of user satisfaction, tool’s effectiveness, usefulness and reliability among other parameters.     

Exogenous coordination of concurrent software components with JavaBIP

A strong separation of concerns is necessary in order to make the design of domain‐specific functional components independent from cross‐cutting concerns, such as concurrent access to the shared resources of the execution platform. Native coordination mechanisms, such as locks and monitors, allow developers to address these issues. However, such solutions are not modular; they are complex to design, debug, and maintain. We present the JavaBIP framework that allows developers to think on a higher level of abstraction and clearly separate the functional and coordination aspects of the system behavior. It implements the principles of the Behavior, Interaction, and Priority (BIP) component framework rooted in rigorous operational semantics. It allows the coordination of existing concurrent software components in an exogenous manner, relying exclusively on annotations, component APIs, and external specification files. We introduce the annotation and specification syntax of JavaBIP and illustrate its use on realistic examples, present the architecture of our implementation, which is modular and easily extensible, and provide and discuss performance evaluation results. Copyright © 2017 John Wiley & Sons, Ltd.     

Numerical evaluation of a heat exchanger with inline tubes of different size for reduced fouling rates

This paper describes the numerical evaluation of a novel cross flow tube bundle heat exchanger that combines tubes of different diameter in an inline arrangement for the purpose of reducing gas side particulate fouling rates while preserving acceptable levels of heat transfer and pressure drop performance. Three arrangements are compared: a common inline tube bundle heat exchanger with cylinders of equal diameter and two other arrangements that consist of alternately placed cylinders with a diameter ratio of d/D = 0.5, at two different transverse spacings. Numerical calculations are performed in order to study heat transfer, pressure drop and fouling rates from flue gases with suspended ash particles. The alternating tube sizes achieve a suppression of the vortex shedding mechanism that has previously been shown to enhance downstream particle deposition. Results show that, compared to the standard arrangement, the tube bundle with unequal cylinders placed at the largest transverse spacing achieves a significant (～30%) reduction in particle deposition rate without sacrificing acceptable values of heat transfer per unit volume and low pressure drop.     

A Single Cysteine Residue in the Translocation Pathway of the Mitosomal ADP/ATP Carrier from Cryptosporidium parvum Confers a Broad Nucleotide Specificity

Cryptosporidiumparvum is a clinically important eukaryotic parasite that causes the disease cryptosporidiosis, which manifests with gastroenteritis-like symptoms. The protist has mitosomes, which are organelles of mitochondrial origin that have only been partially characterized. The genome encodes a highly reduced set of transport proteins of the SLC25 mitochondrial carrier family of unknown function. Here, we have studied the transport properties of one member of the C. parvum carrier family, demonstrating that it resembles the mitochondrial ADP/ATP carrier of eukaryotes. However, this carrier has a broader substrate specificity for nucleotides, transporting adenosine, thymidine, and uridine di- and triphosphates in contrast to its mitochondrial orthologues, which have a strict substrate specificity for ADP and ATP. Inspection of the putative translocation pathway highlights a cysteine residue, which is a serine in mitochondrial ADP/ATP carriers. When the serine residue is replaced by cysteine or larger hydrophobic residues in the yeast mitochondrial ADP/ATP carrier, the substrate specificity becomes broad, showing that this residue is important for nucleotide base selectivity in ADP/ATP carriers.