EXPERIMENTS DURING FLOW BOILING OF A R22 DROP-IN: R422D ADIABATIC PRESSURE GRADIENTS

R22, the HCFC most widely used in refrigeration and air-conditioning systems in the last years, is phasing-out. R422D, a zero ozone-depleting mixture of R125, R134a and R600a (65.1%/31.5%/3.4% by weight, respectively), has been recently proposed as a drop-in substitute. For energy consumption calculations and temperature control, it is of primary importance to estimate operating conditions after substitution. To determine pressure drop in the evaporator and piping line to the compressor, in this paper the experimental adiabatic pressure gradients during flow boiling of R422D are reported for a circular smooth horizontal tube (3.00 mm inner radius) in a range of operating conditions of interest for dry-expansion evaporators. The data are used to establish the best predictive method for calculations and its accuracy: the Moreno-Quibèn and Thome method provided the best predictions for the whole database and also for the segregated data in the annular flow regime. Finally, the experimental data have been compared with the adiabatic pressure gradients of both R22 and its much used alternative R407C available in the literature

Carbon Dioxide Heat Transfer Coefficients And Pressure Drops During Flow Boiling: Assessment Of Predictive Methods

Among the alternatives to the HCFCs and HFCs, carbon dioxide emerged as one of the most promising environmentally friendly refrigerants. In past years many works were carried out about CO2 flow boiling and very different two-phase flow characteristics from conventional fluids were found. In order to assess the best predictive methods for the evaluation of CO2 heat transfer coefficients and pressure gradients in macro-channels, in the current article a literature survey of works and a collection of the results of statistical comparisons available in literature are furnished. In addition the experimental data from University of Naples are used to run a deeper analysis. Both a statistical and a direct comparison against some of the most quoted predictive methods are carried out. Methods implemented both for low–medium pressure refrigerants and specifically developed for R744 are used in the comparison. Some general indications about the choice of the predictive methods dependently on the operating conditions are given

Optimal Trajectory Planning for Cinematography with Multiple Unmanned Aerial Vehicles

This paper presents a method for planning optimal trajectories with a team of Unmanned Aerial Vehicles (UAVs) performing autonomous cinematography. The method is able to plan trajectories online and in a distributed manner, providing coordination between the UAVs. We propose a novel non-linear formulation for this challenging problem of computing multi-UAV optimal trajectories for cinematography; integrating UAVs dynamics and collision avoidance constraints, together with cinematographic aspects like smoothness, gimbal mechanical limits and mutual camera visibility. We integrate our method within a hardware and software architecture for UAV cinematography that was previously developed within the framework of the MultiDrone project; and demonstrate its use with different types of shots filming a moving target outdoors. We provide extensive experimental results both in simulation and field experiments. We analyze the performance of the method and prove that it is able to compute online smooth trajectories, reducing jerky movements and complying with cinematography constraints.Comment: This paper has been published as: Optimal trajectory planning for cinematography with multiple Unmanned Aerial Vehicles. Alfonso Alcantara and Jesus Capitan and Rita Cunha and Anibal Ollero. Robotics and Autonomous Systems. 103778 (2021) 10.1016/j.robot.2021.10377

Monitoring and conservation of archaeological wooden elements from ship wrecks using 3D digital imaging

In marine archaeology, many artifacts made of metallic or organic material are found in different state of conservation depending of the environment in which they are discovered. Once brought to the surface for study or display purposes, the artifacts need to be treated properly otherwise they deteriorate in a short lapse of time. The fragility of organic artifacts and the volumetric variation caused by the marine life on or surrounding them and water lead to the need for measuring the physical dimensions soon after an artifact is extracted from the sea. In an ideal context, it would be appropriate to preserve and restore the archaeological elements rapidly and with the latest methods but due to the large number of artifacts, the cost of complete restoration activities becomes prohibitive for the funding available in public institutions. For this reason, many public laboratories are resorting to digital technologies for documentation, restoration, display and conservation. In this paper, we illustrate the experience of the University of Salento in this area of archaeology using 3D imaging technology. The interest sprang from the need to develop a protocol for documentation and digital restoration of archaeological finds discovered along the coast of Torre S. Sabina (BR) Italy

New Archaeological Evidences of Relative Sea-level Changes along the Coastlines of Apulia (Southern Italy)

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Autonomous Execution of Cinematographic Shots with Multiple Drones

This paper presents a system for the execution of autonomous cinematography missions with a team of drones. The system allows media directors to design missions involving different types of shots with one or multiple cameras, running sequentially or concurrently. We introduce the complete architecture, which includes components for mission design, planning and execution. Then, we focus on the components related to autonomous mission execution. First, we propose a novel parametric description for shots, considering different types of camera motion and tracked targets; and we use it to implement a set of canonical shots. Second, for multi-drone shot execution, we propose distributed schedulers that activate different shot controllers on board the drones. Moreover, an event-based mechanism is used to synchronize shot execution among the drones and to account for inaccuracies during shot planning. Finally, we showcase the system with field experiments filming sport activities, including a real regatta event. We report on system integration and lessons learnt during our experimental campaigns

Recovering actives in multi-antitarget and target design of analogs of the myosin II inhibitor blebbistatin

In multitarget drug design, it is critical to identify active and inactive compounds against a variety of targets and antitargets. Multitarget strategies thus test the limits of available technology, be that in screening large databases of compounds vs a large number of targets, or in using in silica methods for understanding and reliably predicting these pharmacological outcomes In this paper, we have evaluated the potential of several in silica approaches to predict the target, antitarget and physicochemical profile of (S)-blebbistatin, the best-known myosin II ATPase inhibitor, and a series of analogs thereof Standard and augmented structure-based design techniques could not recover the observed activity profiles A ligand-based method using molecular fingerprints was, however, able to select actives for myosin II inhibition Using further ligand- and structure-based methods, we also evaluated toxicity through androgen receptor binding, affinity for an array of antitargets and the ADME profile (including assay-interfering compounds) of the series In conclusion, in the search for (S)-blebbistatin analogs, the dissimilarity distance of molecular fingerprints to known actives and the computed antitarget and physicochemical profile of the molecules can be used for compound design for molecules with potential as tools for modulating myosin II and motility-related diseases

FDEM and ERT measurements for archaeological prospections at Nuraghe S'Urachi (West‐Central Sardinia)

Nuraghe S’Urachi is a monumental architectural complex in West Central Sardinia that was probably first built in the Bronze Age and remained occupied continuously into the early Roman Imperial period. It has been the object of systematic and largescale archaeological investigations in three different phases since 1948 when the first excavations revealed a complex building within a massive defensive wall and multiple towers. Intermittent fieldwork between the 1980s and 2005 subsequently showed that the central nuraghe might comprise up to five principal towers. In 2013, a new collaborative research project, sponsored by Brown University and the Municipality of San Vero Milis, brought together a multidisciplinary research project to investigate this important archaeological site. In this framework, multi-frequency and multi-coil electromagnetic measurements (FDEM) and Electrical resistivity tomography (ERT) were carried out in 2018, 2019, and 2020, over and close to the nuraghe towers, to gain a better understanding of the inner part of the main structure and to investigate the surrounding area that was intensively settled in Phoenician and Punic times. The preliminary results of the geophysical measurements provide new and interesting evidence that supports new hypotheses and suggests possible future archaeological and geophysical strategies to investigate the unexcavated part of the archaeological site of S’Urachi

Encrucijadas sociales de innovación y desarrollo sostenible en Río de Janeiro

Pobreza, desigualdad, falta de acceso a derechos son realidad en las chabolas y periferias brasileñas e impactan directamente a la calidad de vida de estos territorios en los que se desarrollan también pequeñas iniciativas que vislumbran un futuro más sostenible. Este trabajo de investigación discute lo que se conoce como encrucijadas sociales de innovación (Rufino 2019), que son intervenciones hechas en las roturas del sistema y que funcionan como una forma de transgresión/impugnación de las instituciones ya establecidas. Son desarrolladas por un emprendedor social “a la brasileña” —o virador (Souza Neto 2003)— cuya impugnación puede ser vista a partir de sus nuevas formas de hacer, conocer, encuadrar y organizar (Haxeltine et al. 2016), presentadas en 3 casos: Barkus, negocio social de educación financiera para jóvenes y adultos; G10, red de las 10 chabolas de mayor poder de compra en el Brasil, y Olabi, espacio de democratización de tecnologías para transformación social. A partir de ahí, se identifican 7 lecciones sobre las características clave de este tipo de innovación social. En conclusión, se determina que las encrucijadas sociales de innovación de Brasil son motores para la transformación social, las que abren camino a modelos alternativos de futuro con enfoque en el desarrollo local sostenible y en la mejoría de la calidad de vida de las poblaciones vulnerables

Negócios de impacto socioambiental no Brasil: como empreender, financiar e apoiar

Negócios de impacto socioambiental no Brasil: como empreender, financiar e apoiar Edgard Barki, Graziella Maria Comini y Haroldo da Gama Torres Rio de Janeiro: Fundação Getúlio Vargas / Instituto de Cidadania Empresarial, 201