Síntesis del ácido iso-13-metil-tetradecanoico y sus triglicéridos

A new and more convenient synthesis of the isofatty acid 13-methyl-tetradecanoic acid and its triglyceride is described here. This isofatty acid is prepared through elongation of the undecanoic acid chain with isobutyraldehyde according to Wittig by the reaction between bromo-undecanoic acid ethyl ester-triphenylphosphonium salt and sodium methoxide followed by the addition of isobutyraldehyde. Its triglyceride is formed by the esterification of the free isofatty acid with glycerin without catalyst. Its purity was over 99% after high refining over activated silica gel. Total yield was estimated to be 22,8%.Una nueva y práctica síntesis del ácido graso iso-13-metil- tetradecanoico y sus triglicéridos se describe aquí. Este iso- ácido graso se prepara a través de la elongación de la cadena del ácido undecanoico con isobutiraldehido según Wittig por reacción entre la sal de bromuro de undecanoico etil-éster trifenilfosfonio y metilato sódio seguido de la adición de isobutiraldehido. Su triglicérido está formado por la esterificación del iso ácido graso libre con glicerina sin catalizador. Su pureza es superior al 99%, después de una alta refinación sobre gel de sílice activado. El rendimiento total se estimó en el 22,8%

AESTHETIC CHARACTERISTICS OF GREEK ORNAMENTAL STONES ASSOCIATED WITH MINERAL, GEOCHEMICAL AND STRUCTURAL PROPERTIES

Τα εμπορικά μάρμαρα αποτελούν υλικά που δεν απαιτούν ιδιαίτερη επεξεργασία με υψηλή οικονομική αξία για την κατασκευαστική βιομηχανία. Τα πιο σημαντικάδιακοσμητικά πετρώματα στην Ελλάδα περιλαμβάνουν ασβεστόλιθους και μάρμαρα με ιδιαίτερα ποιοτικά χαρακτηριστικά και θεωρούνται προϊόντα ιδιαίτερης εμπορικής αξίας. Σε αυτή την εργασία μελετήθηκαν εβδομήντα τρία ανθρακικά δείγματα (ασβεστόλιθοι, δολομίτες και μάρμαρα) από όλη την Ελλάδα με σκοπό να καθοριστούν τα μακροσκοπικά και πετρογραφικά χαρακτηριστικά τους και να διερευνηθεί η ορυκτοχημική τους σύσταση και η γεωχημεία τους. Τα χρώματά τους ποικίλουν από λευκό έως τεφρό, εξαιτίας του περιεχομένου τους σε ασβεστίτη και δολομίτη, μαύρο σε βιτουμενιούχους ασβεστόλιθους, κίτρινο εξαιτίας της παρουσίας οξειδίων σιδήρου και αργιλικών ορυκτών, κόκκινο εξαιτίας των οξειδίων σιδήρου και μεικτών φάσεων ασβεστίτη και σιδηρίτη, καστανοπράσινο εξαιτίας της εμφάνισης οξειδίων σιδήρου μαζί με χλωρίτη και μοσχοβίτη, προσδίδοντας σχιστότητα στο πέτρωμα. Διάσπαρτες ασβεστιτικές και δολομιτικές φλέβες, όπως επίσης και εμφάνιση άλλων ορυκτών φάσεων όπως βαρύτης, επίδοτο και μαγνητίτης συμβάλλουν στη δημιουργία ιδιαίτερωνχαρακτηριστικών που προσδίδουν μοναδική εμφάνιση. Τα χαρακτηριστικά γνωρίσματα κάθε πετρώματος εξαρτώνται σημαντικά από το είδος των ορυκτών, τη σύσταση, κοκκομετρία και κατανομή τους, τη γεωχημεία και δομή τους.Commercial marble are almost ready-to-use materials with a high economic value for the building-construction industry. The most important ornamental stones in Greece include limestone and marble with notable qualitative features and are considered products of high commercial value. In this research, seventy-three carbonate samples (limestones, dolomites and marbles) from all over Greece have been studied to determine their macroscopic and petrographic features and to investigate their mineral chemistry and geochemistry. Their colors vary from whitish to gray due to their content of calcite and dolomite, black due to bitumens, yellow due to the presence of iron oxides and clay, red due to iron oxides and mixed phases of calcite- siderite, green-brownish due to the presence of iron oxides or muscovite and chlorite, giving schistosity to the rock. Scattered calcite and dolomite veins, as well as the occurrence of other minerals such as barite, epidote and magnetite, contribute to specific features, thus making their appearance unique. The particular characteristics of each stone depend highly upon the type of minerals present, their composition, grain size and extent of aggregation, their geochemistry and structure

HAPI: Hardware-Aware Progressive Inference

Convolutional neural networks (CNNs) have recently become the state-of-the-art in a diversity of AI tasks. Despite their popularity, CNN inference still comes at a high computational cost. A growing body of work aims to alleviate this by exploiting the difference in the classification difficulty among samples and early-exiting at different stages of the network. Nevertheless, existing studies on early exiting have primarily focused on the training scheme, without considering the use-case requirements or the deployment platform. This work presents HAPI, a novel methodology for generating high-performance early-exit networks by co-optimising the placement of intermediate exits together with the early-exit strategy at inference time. Furthermore, we propose an efficient design space exploration algorithm which enables the faster traversal of a large number of alternative architectures and generates the highest-performing design, tailored to the use-case requirements and target hardware. Quantitative evaluation shows that our system consistently outperforms alternative search mechanisms and state-of-the-art early-exit schemes across various latency budgets. Moreover, it pushes further the performance of highly optimised hand-crafted early-exit CNNs, delivering up to 5.11x speedup over lightweight models on imposed latency-driven SLAs for embedded devices.Comment: Accepted at the 39th International Conference on Computer-Aided Design (ICCAD), 202

SPINN: Synergistic Progressive Inference of Neural Networks over Device and Cloud

Despite the soaring use of convolutional neural networks (CNNs) in mobile applications, uniformly sustaining high-performance inference on mobile has been elusive due to the excessive computational demands of modern CNNs and the increasing diversity of deployed devices. A popular alternative comprises offloading CNN processing to powerful cloud-based servers. Nevertheless, by relying on the cloud to produce outputs, emerging mission-critical and high-mobility applications, such as drone obstacle avoidance or interactive applications, can suffer from the dynamic connectivity conditions and the uncertain availability of the cloud. In this paper, we propose SPINN, a distributed inference system that employs synergistic device-cloud computation together with a progressive inference method to deliver fast and robust CNN inference across diverse settings. The proposed system introduces a novel scheduler that co-optimises the early-exit policy and the CNN splitting at run time, in order to adapt to dynamic conditions and meet user-defined service-level requirements. Quantitative evaluation illustrates that SPINN outperforms its state-of-the-art collaborative inference counterparts by up to 2x in achieved throughput under varying network conditions, reduces the server cost by up to 6.8x and improves accuracy by 20.7% under latency constraints, while providing robust operation under uncertain connectivity conditions and significant energy savings compared to cloud-centric execution.Comment: Accepted at the 26th Annual International Conference on Mobile Computing and Networking (MobiCom), 202

Characterisation and targets

The State of the Art Edition on Ornamental and Dimensional Stones Characterisation points out and synthesises, for the first time in a unique presentation, all aspects concerning general and fundamental problems of the stone product qualification. The Edition focuses on the three main aspects of characterisation, as the several and different "objects" of interest to be characterised, the modern technology available and the environmental standards. A complete list of references supports each of those three main topic

Characterisation and targets

The State of the Art Edition on Ornamental and Dimensional Stones Characterisation points out and synthesises, for the first time in a unique presentation, all aspects concerning general and fundamental problems of the stone product qualification. The Edition focuses on the three main aspects of characterisation, as the several and different “objects” of interest to be characterised, the modern technology available and the environmental standards. A complete list of references supports each of those three main topics

Petrological and geochemical properties of greek carbonate stones, associated with their physico-mechanical and aesthetic characteristics

Greece is considered amongst the world’s top marble producers in the global carbonate ornamental stone market. Selected Greek carbonate ornamental stones considered in our study suite are characterized by their distinctive and in some cases unique appearance, having a significant impact on their commercial value. Their wide range of colour varieties and their physico-mechanical properties are closely related to their mineral assemblage, chemical constitution, petrographic properties, structural defects, which in turn depend highly upon their metamorphic/diagenetic grade and in some cases hydrothermal processes that affected them. This study endeavors to feature the petrographic, mineralogical and geochemical properties of the main Greek carbonate ornamental stones from selected localities and their by-product waste material used as aggregates. The documented data aims to serve a better understanding of the dynamic Greek marble industry by relating their mineral and chemical properties with their physico-mechanical and aesthetic characteristics. © 2020 by the authors. Licensee MDPI, Basel, Switzerland