A FRAMEWORK FOR SHARING ONLINE LABORATORY RESOURCES

ABSTRACT Numerous online laboratory resources have been and continue to be developed by many educational institutions around the world. These resources include both remote laboratories, which are based on actual experimental devices accessed remotely, as well as virtual laboratories, which represent software simulations of experiments. In the vast majority of the cases, the remotely accessible online laboratories reported on in the literature represent stand-alone systems, which are typically difficult to share by large numbers of learners dispersed at various educational institutions. This has led to the existence of many functionally similar, but independently operating systems developed in many places. This paper will identify the common features of such online laboratory resources. Then, the framework for a network of interconnected resource managers, which facilitate the efficient implementation and deployment of as well as the subsequent search for and shared usage of online laboratory resources (e.g. remote experiments, virtual experiments, game-based environments, etc.), will be presented. A centralized resource repository is presented that enables the publishing of information on the existence and availability of specific resources through the network. Finally, an example is given that illustrates the issues relating to joining, publishing, searching for and accessing online laboratory resources in that framework

Evaluation of low-rank coals as raw material for Fe and Ca organomineral fertilizer using a new EDXRF method

A rapid and reliable method for analyzing Fe and Ca in low-rank Greek coals was developed. The presence of Fe and Ca is of importance regarding the potential use of these coals as raw material for organomineral fertilizers. Samples were collected from the main Greek lignite deposits and standards were prepared using Atomic Absorption Spectroscopy (AAS), which were also employed in the Energy Dispersive X-ray Fluorescence (EDXRF) method. The new method offers the advantages of being timesaving, non-destructive and can be easily incorporated in a fertilizer production line. Analysis of low-rank Greek coals demonstrated a significant Fe and Ca content ranging from 0.15 to 1.97 wt.% for Fe and from 0.04 to 2.51 wt.% for Ca. When both EDXRF and AAS techniques were applied, the Fe and Ca concentration values differed less than 5%, demonstrating that both techniques are reliable for low-rank coals in the above concentration range. These EDXRF results may be used as a preliminary test regarding the application of Greek coals in organomineral fertilizer production, given that in these coals iron and calcium are the most abundant metals. © 2008 Elsevier B.V. All rights reserved

Chemistry of metal-humic complexes contained in Megalopolis lignite and potential application in modern organomineral fertilization

Lignite samples from two deposits located in the Megalopolis Basin, Southern Greece, were evaluated for their potential applicability as raw materials for the production of organomineral fertilizers. Fundamental chemical analyses were carried out to demonstrate high humic substances and metal contents. To determine their relative distribution in the Megalopolis lignite extract, eight elements, namely Na, K, Cd, Mn, Mg, Pb, Zn, and Cu, were studied both in H2O and in Na4P2O7/NaOH solutions. The behavior of these metals showed significant variations; Zn, Pb, Cd, and Cu associate mostly to the humic substances and proved scarce in the water extract. Contrarily, K and Mg gave a significantly low total yield in the Na4P2O7/NaOH solution, while Mn was classified among the least extracted elements. Further enrichment of Megalopolis humic substances in these metals was achieved; Pb and Mg proved the most and least retained metal, respectively. Decomplexation titration curves of humic matter saturated with these metal ions demonstrated that novel organomineral fertilizing materials may develop based on optimized metal ion and humate contents, which can retain metals in a soluble form within a wide pH range. Formation of complexes between humic substances and Zn, Cd, and Mg was clearly indicated. © 2009 Elsevier B.V. All rights reserved

Multidisciplinary Parametric Design Optimization for Enhancing the Affordability of Molded Composites

The role of design optimization in assisting design decision-making and enhancing the affordability of composite products is studied in this paper. The design of composite products that meet performance, manufacturability, and cost requirements is a multidisciplinary problem. Solutions to appropriately formulated design optimization problems can assist in quickly examining several design alternatives at early conceptual design and parametric design stages. However, the candidate designs require manufacturing process, structural and material performance, and product cost evaluations. These evaluations are often conducted by several domain experts using sophisticated and diverse numerical analysis tools. The formulation of constraint and objective functions in multiple domains, the use of numerical model-based evaluation of the functions, and the solution of multidisciplinary optimization problems during the design of injection molded plastics are addressed in this paper. Numerical examples are presented illustrating the application of optimization techniques in process and exploring material alternatives as well as in parametric design of geometry with affordable cost objectives. A brief description of a software system developed to systematically integrate optimization with the domain-dependent knowledge and geometric design is also presented. </jats:p

On Infrastructures for Educational Online Laboratories

This book chapter focuses on online laboratories for educational use, with special emphasis on experiments suitable for engineering and science curricula at the undergraduate level. It starts with a brief review of the early history and current state of the art of online experiments and a discussion of the benefits of existing online laboratory systems. Then, their shortcomings and limitations are critically examined, followed by some thoughts on a possible framework for better leveraging the world-wide development efforts by creating a virtual organization for online laboratories. Finally, some issues related to the efficient management and global sharing of online laboratory resources are raised and a series of cybersecurity problems arising in the context of commercial transactions between educational institutions are described.</jats:p

Studies of the low-rank Greek coals. 1. Classification

Physical and chemical measurements of Greek coals lead to a classification by rank into five categories, ranging from subbituminous C to peat. This classification is further documented by ESR spectroscopy and powder X-ray diffraction. In order to accommodate all the deposits, a new category is introduced between lignite B and peat, designated as lignitized peat, which is clearly and operationally distinguished from peat and higher-rank lignites. © 1989

Fe(III)-humate complexes from Megalopolis peaty lignite: A novel eco-friendly fertilizer

Fe(III)-humate complexes were synthesized from Greek peaty lignite of the Megalopolis Basin. The preparation was carried out under mild and low-energy conditions producing a biodegradable, eco-friendly and effective material to substitute the synthetic chelates Fe-EDDHA, Fe-EDTA and Fe-DTPA. Due to both the existing expanded configuration of the humic substances (that make binding sites accessible to the metal ions) and the ionization of functional groups, alkaline environment facilitates the association between Fe(III) ions and the lignite-derived humic substances. UV-vis and IR spectra revealed coordination of the metal ions with the carboxylic and phenolic groups of the oxygen-rich humic substances. Fe(III)-humate complexes were proved stable in a wide pH range similar to Fe-EDDHA synthetic chelates. Furthermore, the presence of K+ and humic matter increases the agronomic value of this material establishing alternative applications for Megalopolis peaty lignite. © 2009 Elsevier Ltd. All rights reserved

Innovative biocatalytic production of soil substrate from green waste compost as a sustainable peat substitute

In the present work, a new simple and quick eco-friendly method is discussed to handle effectively the green wastes and produce a sustainable peat substitute of high quality on the large scale. Principal physicochemical parameters, i.e., temperature, moisture, specific weight, pH, electrical conductivity and, also, microorganisms, organic matter, humic substances, total Kjeldahl nitrogen and total organic carbon, C/N ratio, ash, metal content and phytotoxicity, were monitored systematically. Humic substances content values were interrelated to both C/N ratio and pH values and, similarly, bulk density, TOC, TKN, C/N, GI, ash and organic matter were found interconnected to each other. A novel biocatalyst, extremely rich in soil microorganisms, prepared from compost extracts and peaty lignite, accelerated the biotransformation. Zeolite was also employed. The compost does not demonstrate any phytotoxicity throughout the entire biotransformation process and has increased humic substances content. Both humic substances content and germination index can be employed as maturation indices of the compost. Addition of compost, processed for 60 days only, in cultivations of grass plants led to a significant increase in the stem mass and root size, annotating the significant contribution of the compost to both growth and germination. The product obtained is comparable to peat humus, useful as peat substitute and can be classified as a first class soil conditioner suitable for organic farming. © 2016 Elsevier Lt