3,114 research outputs found

    Parsing and Printing Java 7-15 by Extending an Existing Metamodel

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    Many technologies and frameworks are built upon the open source Eclipse Modelling Framework (EMF) to provide model-based software development or even model-based consistency preservation of software artifacts. In this context, not only EMF-based modeling of the source code but also parsing of the source code and printing the model again into source code files are required. The Java Model Parser and Printer (JaMoPP) provides an EMF-based environment for modeling, parsing and printing Java source code. However, it supports just the syntax of Java 5 and 6. Moreover, JaMoPP is based on some technologies that have technical problems and have not been further maintained. In this work, we extend the metamodel of JaMoPP to support Java versions 7-15. Our extensions expand the metamodel with new features, for instance, the diamond operator, lambda expressions, or modules. Moreover, we implemented our new parser and printer. The parser implementation is based on the Eclipse Java Development Tools (JDT) that is well maintained, which reduces the maintenance effort to extend our JaMoPP for new versions of Java

    Commit-Based Continuous Integration of Performance Models

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    Micro/Mesoporous Zeolitic Composites: Recent Developments in Synthesis and Catalytic Applications

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    Micro/mesoporous zeolitic composites (MZCs) represent an important class of hierarchical zeolitic materials that have attracted increasing attention in recent years. By introducing an additional mesoporous phase interconnected with the microporosity of zeolites, a hierarchical porous system of MZCs is formed which facilitates molecular transport while preserving the intrinsic catalytic properties of zeolites. Thus, these materials offer novel perspectives for catalytic applications. Over the years, numerous synthesis strategies toward the formation of MZCs have been realized and their catalytic applications have been reported. In this review, the three main synthesis routes, namely direct synthesis using zeolite precursors, recrystallization of zeolites, and zeolitization of preformed mesoporous materials are thoroughly discussed, with focus on prior works and the most recent developments along with prominent examples given from the literature. In addition, the significant improvement in the catalytic properties of MZCs in a wide range of industrially relevant reactions is presented through several representative cases. Some perspectives for the future development of MZCs are also given

    Perspective on Co-feeding of Phenolic Compounds into Existing Refinery Units

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    Replacement of fossil materials by renewable feedstocks is forced by depletion and environmental concerns but requires new technologies for energy generation or production of chemicals. Co-processing of petroleum with renewable feedstocks in current refinery infrastructure is an attractive option in the mid-term to increase renewable fuel capacity, as the capital investment and operational costs would be marginal. In this chapter, various strategies for admixing of phenolic compounds as renewable feeds into standard refineries are described. Starting from the role of renewable resources (e.g. biomass, lignin and bio-oil) in the current and future energy and chemical community, an overview on the present energy supply situation and the role of phenolic compounds are discussed. Later, a summary on co-feeding of phenolic model compounds with conventional feeds in refineries are illustrated. The co-processing of upgraded bio-oil in refinery units [e.g. fluid catalytic cracking (FCC), hydrotreating] is summarized, showing the potential utilisation of bio-feeds via such processes. Finally, some concluding remarks address the perspectives for further research and development to overcome future challenges

    Methanation of CO2 on Ni/Al2O3 in a Structured Fixed-Bed Reactor—A Scale-Up Study

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    Due to the ongoing change of energy supply, the availability of a reliable high-capacity storage technology becomes increasingly important. While conventional large-scale facilities are either limited in capacity respective supply time or their extension potential is little (e.g., pumped storage power stations), decentralized units could contribute to energy transition. The concepts of PtX (power-to-X) storage technologies and in particular PtG (power-to-gas) aim at fixation of electric power in chemical compounds. CO2 hydrogenation (methanation) is the foundation of the PtG idea as H2 (via electrolysis) and CO2 are easily accessible. Methane produced in this way, often called substitute natural gas (SNG), is a promising solution since it can be stored in the existing gas grid, tanks or underground cavern storages. Methanation is characterized by a strong exothermic heat of reaction which has to be handled safely. This work aims at getting rid of extreme temperature hot-spots in a tube reactor by configuring the catalyst bed structure. Proof of concept studies began with a small tube reactor (V = 12.5 cm3) with a commercial 18 wt % Ni/Al2O3 catalyst. Later, a double-jacket tube reactor was built (V = 452 cm3), reaching a production rate of 50 L/h SNG. The proposed approach not only improves the heat management and process safety, but also increases the specific productivity and stability of the catalyst remarkably

    THE H3/H4 HISTONE GENE CLUSTER OF LAND SNAILS (GASTROPODA: STYLOMMATOPHORA): TS/TV RATIO, GC3 DRIVE AND SIGNALS IN STYLOMMATOPHORAN PHYLOGENY

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    Histone gene primers were developed for land snails (Stylommatophora). The partial H3/H4 histone gene cluster was cloned and sequenced for 18 species. Transcription of the H3 and H4 genes was divergent (each gene is transcribed in the opposite direction) as has been found for other protostome and diploblast animals, with the exception of Mytilus. In the bivalve Mytilus transcription of both genes occurs in the same direction, i.e. land snails and bivalves seem to differ in their histone gene organization. The non-transcribed H3/H4 spacer varied in length between 279 and 691 basepairs. Nucleotide polymorphisms in this non-transcribed spacer might be of significance to study phylogenetics and systematics of closely related species and genera. As expected, the coding regions exhibited no amino acid substitution among land snail species. However, one amino acid substitution was found in comparison between land snails and Drosophila. The transition/transversion (TS/TV) ratio of H3 and H4 was predominately shaped by the third codon position and ranged in most cases from 1.0 to 2.0, indicating low nucleotide saturation. GC content was calculated for the third codon position (GC3 index at the ‘wobble' base position). The histone GC3 values were far lower in land snails than values currently available for other genomes (i.e. mammals). This indicates that H3/H4 histone wobble bases of land snails evolve without strong GC drive. Phylogenetic trees were reconstructed from the coding regions. We used Succinea putris (Elasmognatha) as outgroup. Trichia villosa (Helicoidea) showed six apomorphic nucleotide signals. Moreover, the nucleotide signals give evidence that the Cochlicopidae, Vertiginidae and Valloniidae are paraphyletic family categories. The paraphyletic status of cochlicopid, vertiginid and valloniid gastropods is also supported by our unpublished ribosomal DNA tree

    Continuous Integration of Architectural Performance Models with Parametric Dependencies – The CIPM Approach

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    Explicitly considering the software architecture supports efficient assessments of quality attributes. In particular, Architecture-based Performance Prediction (AbPP) supports performance assessment for future scenarios (e.g., alternative workload, design, deployment, etc.) without expensive measurements for all such alternatives. However, accurate AbPP requires an up-to-date architectural Performance Model (aPM) that is parameterized over factors impacting performance like input data characteristics. Especially in agile development, keeping such a parametric aPM consistent with software artifacts is challenging due to frequent evolutionary, adaptive and usage-related changes. The shortcoming of existing approaches is the scope of consistency maintenance since they do not address the impact of all aforementioned changes. Besides, extracting aPM by static and/or dynamic analysis after each impacting change would cause unnecessary monitoring overhead and may overwrite previous manual adjustments. In this article, we present our Continuous Integration of architectural Performance Model (CIPM) approach, which automatically updates the parametric aPM after each evolutionary, adaptive or usage change. To reduce the monitoring overhead, CIPM calibrates just the affected performance parameters (e.g., resource demand), using adaptive monitoring. Moreover, CIPM proposes a self-validation process that validates the accuracy, manages the monitoring and recalibrates the inaccurate parts. As a result, CIPM will automatically keep the aPM up-to-date throughout the development time and operation time, which enables AbPP for a proactive identification of upcoming performance problems and evaluating alternatives at low costs. CIPM is evaluated using three case studies, considering (1) the accuracy of the updated aPMs and associated AbPP and (2) the applicability of CIPM in terms of the scalability and the required monitoring overhead

    Understanding the Performance and Stability of Supported Ni-Co-Based Catalysts in Phenol HDO

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    Performances of bimetallic catalysts (Ni-Co) supported on different acidic carriers (HZSM-5, HBeta, HY, ZrO2) and corresponding monometallic Ni catalysts in aqueous phase hydrodeoxygenation of phenol were compared in batch and continuous flow modes. The results revealed that the support acidity plays an important role in deoxygenation as it mainly controls the oxygen-removing steps in the reaction network. At the same time, sufficient hydrothermal stability of a solid catalyst is essential. Batch experiments revealed 10Ni10Co/HZSM-5 to be the best-performing catalyst in terms of conversion and cyclohexane yield. Complementary continuous runs provided more insights into the relationship between catalyst structure, efficiency and stability. After 24 h on-stream, the catalyst still reveals 100% conversion and a slight loss (from 100% to 90%) in liquid hydrocarbon selectivity. The observed alloy of Co with Ni increased dispersion and stability of Ni-active sites, and combination with HZSM-5 resulted in a well-balanced ratio of metal and acid sites which promoted all necessary steps in preferred pathways. This was proved by studies of fresh and spent catalysts using various characterization techniques (N2 physisorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and infrared spectroscopy of adsorbed pyridine (pyr-IR))

    Simulating the soil phosphorus dynamics of four long‐term field experiments with a novel phosphorus model

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    Phosphorus is a nonrenewable resource, which is required for crop growth and to maintain high yields. The soil P cycle is very complex, and new model approaches can lead to a better understanding of those processes and further guide to research gaps. The objective of this study was to present a P-submodel, which has been integrated in the existing Carbon Candy Balance (CCB) model that already comprises a C and N module. The P-module is linked to the C mineralization and the associated C-pools via the C/P ratio of fresh organic material. Besides the organic P cycling, the module implies a plant-available P-pool (Pav), which is in a dynamic equilibrium with the nonavailable P-pool (Pna) that comprises the strongly sorbed and occluded P fraction. The model performance was tested and evaluated on four long-term field experiments with mineral P fertilization, farmyard manure as organic fertilizer and control plots without fertilization. The C dynamics and the Pav dynamics were modelled with overall good results. The relative RMSE for the C was below 10% for all treatments, while the relative RMSE for Pav was below 15% for most treatments. To accommodate for the rather small variety of available P-models, the presented CNP-model is designed for agricultural field sites with a relatively low data input, namely air temperature, precipitation, soil properties, yields and management practices. The CNP-model offers a low entry threshold model approach to predict the C-N and now the P dynamics of agricultural soils.Fachagentur Nachwachsende Rohstoffe http://dx.doi.org/10.13039/501100010812Peer Reviewe
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