bluuebunny/crossref_metadata_2025_split huggingface dataset:
Urban Building Energy Modeling: an hourly energy balance model of residential buildings at a district scale
Authors: Mutani G , Todeschi V 
Published: September 2020

Abstract
The energy consumption of buildings is related to several factors, such as the construction and geometric characteristics, occupancy, climate and microclimate conditions, solar exposure, and urban morphology. However, the interaction between buildings and the surrounding urban context should also be taken into consideration in energy consumption models. The aim of this work has been to create a bottom-up model in order to evaluate the energy balance of residential buildings at an urban scale, starting from the hourly energy consumption data. This modeling approach considers the building characteristics together with urban variables to describe the energy balance of the built environment; it can therefore be used to manage heterogeneous types of data at different scales and it can offer accurate spatial-temporal information on the energy performance of buildings. Detailed heat balance methods can be used at a building scale to estimate heating loads, but this urban-scale simplified model can also be used as a decision tool to support urban design explorations and for policy purposes. This urban energy consumption model was verified for a case study of a district in Turin, Italy, with the support of a GIS tool, considering hourly energy consumption data of about 50 residential users for two or three consecutive heating seasons. The results show that a simplified model, based on low quality and quantity data, which are typical of an urban scale, can be a powerful tool for the evaluation and spatial representation of the energy needs of buildings at an urban scale.
Load-shifting strategies in district heating networks with constant supply temperature: the case study of Verona
Authors: Vivian J , Quaggiotto D , Ploner E , D’Isep F , Zarrella A 
Published: September 2020

Abstract
District heating and cooling networks are a key infrastructure to decarbonise the heating and cooling sector. Besides the design of new networks according to the principles of the 4th and 5th generation district heating, operational aspects may significantly contribute to improve the efficiency of existing networks from both economic and environmental standpoints. In the present work, computer simulations using a district heating network model (NeMo) were carried out to investigate the load shifting potential offered by the thermal capacitance of the water volume enclosed in the network pipelines. The average return temperature is increased before the occurrence of the peak load by adjusting the flow rate according to the forecasted heat demand for the upcoming hours. The effectiveness of this control strategy was demonstrated for the district heating network of Verona, proving that the peak load can be significantly reduced, especially during middle season. Finally, the load shifting strategy was used to allow a change in the heat production mix, thereby reducing the primary energy consumption of the main heat supply station during the considered period.
A multiscale fluid structure interaction model derived from Koiter shell equations
Authors: Chierici A , Chirco L , Giovacchini V , Manservisi S , Santesarti G 
Published: September 2020

Abstract
In this work we propose the numerical simulation of fluid structure interaction (FSI) problem by using a membrane model, derived from the Koiter shell equations. With this approach the thickness of the solid wall can be neglected, with a meaningful reduction of the computational cost of the numerical problem. The fluid structure problem is then reduced to the fluid equations on a moving mesh together with a particular Robin boundary condition imposed on the surface corresponding to the solid moving wall. Furthermore an artificial absorbing outflow boundary condition has been implemented in order to reduce the damping and reflections of the pressure waves at the domain’s outlet. This model is implemented and solved with an in-house finite elements code, and tested through axisymmetric cases that show the robustness of the developed algorithm. Finally, we report a comparison of the implemented model with results of a FSI monolithic model, based on non-linear incompressible structure.
An adjoint-based temperature boundary optimal control approach for turbulent buoyancy-driven flows
Authors: Chirco L , Giovacchini V , Manservisi S 
Published: September 2020

Abstract
This paper deals with the adjoint optimal control for turbulent buoyancy-driven flows. The aim of this optimal control problem is to obtain a desired velocity profile and enhance the turbulence intensity in a well defined region by controlling the fluid temperature on domain boundaries and consequently the buoyancy forces. The fluid is assumed to be incompressible within the Boussinesq approximation, while turbulence is considered by coupling the Wilcox k-ω model with the Reynolds Averaged energy and Navier Stokes equations. The state, adjoint and control equations are derived by employing the Lagrangian multipliers method. The optimality system is solved with a finite elements code where a steepest descent algorithm has been implemented in order to find the optimal boundary control parameter. Numerical results are reported to show the robustness of the method in solving strongly-coupled optimality systems with a large number of unknowns.
Development and calibration of a 1D thermo-fluid dynamic model of ventilation in tunnels
Authors: Cingi Pietro , Angeli Diego , Cavazzuti Marco , Levoni Paolo , Cipollone Maurizio 
Published: September 2020

Abstract
In complex, large civil infrastructures where ventilation has a crucial role for the safety of users in both normal operation and hazardous scenarios, the correct prediction of flow and heat transfer parameters is of fundamental importance. While full 3D simulation is applicable only to a limited extent, and the resort to 1D modeling is a common practice in both design and evaluation phases, the limitation of such models lies in the choice of transfer parameters, such as friction loss coefficients and heat transfer coefficients. In this work, an original approach based on the Finite Volume integration of the 1D flow and energy equations is presented. Such equations are to be solved on a network of ducts, representing the ventilation system in the 11.6 km long Mont Blanc Tunnel with a spatial resolution of 10 m. A preliminary calibration of a set of friction loss coefficients against a rich experimental dataset collected throughout a dedicated set of in situ tests is of particular concern here, as it is carried out by means of genetic optimization algorithms. Predictions of the flow field are in remarkable agreement with the experimental data, with an overall RMS error of ± 0.42 m/s. Further refinements and possible parameter choices are also discussed.
A simple test method for measurement of the interface thermal resistance of coated and uncoated metal surfaces
Authors: Pedrazzi S , Vergnano A , Allesina G , Veronesi P , Leali F , Tartarini P , Muscio A 
Published: September 2020

Abstract
Molds for metal casting are often internally coated in order to minimize the interaction between the steel surface of the mold and the melted metal during its pouring and solidification. However, the added coating increases the thermal interface resistance during the cooling process and it can thus affect the process itself. For example, numerical predictions and experimental results are matched only if the interface resistance is even quintupled in the presence of the usual interface coating, compared to the uncoated mold. In order to have a reasonable estimate of the interface thermal resistance, an easy to use measurement approach has been tested. This consists of contacting a cold and a hot samples of metals with known thermal properties, one at ambient temperature and the other one much hotter. The temperatures of the two samples, assumed to be uniform in each sample, are measured by thermocouples placed inside the samples through a hole, and the interface resistance is calculated from the time evolution pattern of those temperatures during the thermal transient that follows the instant in which the samples have been contacted.
Condensation and vaporization heat transfer of low-GWP mixtures
Authors: Bortolin S , Azzolin M , Berto A , Guzzardi C , Del Col D 
Published: September 2020

Abstract
The present work investigates the heat transfer performance of non-azeotropic ternary low-GWP (Global Warming Potential) mixtures during condensation and vaporization inside a 8.0 mm inner diameter channel. The tested mixtures are R455A, which is a ternary blend of R32, R1234yf and R744 (21.5/75.5/3.0% by mass composition), and R452B, which is a ternary blend of R32, R1234yf and R125 (67.0/26.0/7.0% by mass composition). R455A presents a GWP100-years value equal to 146 and a temperature glide of 10 K at pressure p=17.6 bar, while R452B is characterized by higher GWP, equal to 676, but lower temperature glide, about 1 K at p=22.9 bar. Condensation tests have been run with the two mixtures R455A and R452B at a mean saturation temperature (average value between dew point and bubble point temperatures at constant pressure and given composition) equal to 40 °C and mass velocity ranging between 100 and 600 kg m−2 s−1. Flow boiling tests have been performed at around 18 °C mean saturation temperature and mass velocity ranging between 200 and 400 kg m−2 s−1. The effects of vapor quality, mass velocity and heat flux on the heat transfer coefficient are investigated. Moreover, the adoption of zeotropic mixtures poses the problem of how to extend the correlations developed for pure fluids. In the present paper, the contribution of the mass transfer resistance is assessed and the corrections needed in the models are discussed.
Effect of Refrigerant Properties Estimation on the Prediction Capabilities of Well-Established Two-Phase Heat Transfer and Pressure Drop Models for New Refrigerants
Authors: Righetti G , Akasaka R , Bobbo S , Brown J S , Fedele L , Higashi Y , Longo G A , Mancin S , Zilio C 
Published: September 2020

Abstract
R1233zd(E) and R1224yd(Z) are two HCFO (Hydro Chloro Fluoro Olefin) low-GWP refrigerants recently proposed as substitutes of the HFC (Hydro Fluoro Carbon) fluids commonly used in air conditioning, high temperature heat pumps and ORC applications. A few experimental works regarding the two phase heat transfer in small diameter smooth and microfin tubes have already been published in the open literature. The estimations of thermophysical properties may have a remarkable impact on the prediction of the heat transfer coefficients and pressure drops, especially during two-phase heat transfer. The thermophysical properties databases and predictive tools for these refrigerants are continuously being updated and improved as additional, accurate measurements are published in the open literature. The present paper aims to highlight the impacts of thermophysical properties prediction models on the consistency of estimations of heat transfer coefficient and pressure drop using correlations published in the open literature. As a benchmark, some experimental heat transfer and pressure drop data collected for two new HCFOs, R1233zd(E) and R1224yd(Z) are used. The experimental database has been collected at the Department of Management and Engineering of the University of Padova. For the thermophysical properties estimations, different Equations of States contained in REFPROP as well as a more “simplified” approach based on group contribution methods coupled with a Peng-Robinson Equation of State, are considered.
An integrated CO2 unit for heating, cooling and DHW installed in a hotel. Data from the field.
Authors: Tosato Giacomo , Girotto Sergio , Minetto Silvia , Rossetti Antonio , Marinetti Sergio 
Published: September 2020

Abstract
This paper presents a new heat pump unit intended to provide heating, cooling and hot water to a hotel and using CO2 as the working fluid. The heat pump was installed in mid-2018 in a hotel located in a touristic area in North Italy and open nearly all over the year. The unit can benefit from ground water as heat source or heat sink. The heat pump features a two-phase multi-ejector as expansion device. An original two-evaporator lay-out is implemented, where the first one is gravity driven and the second one is ejector driven. It is fully equipped with measurement instruments, data acquisition system and cloud data storage, developed and tailored for the unit. The unit was developed, instrumented, installed and monitored within the H2020 MultiPACK project, which aims at building confidence in integrated heating, ventilation, air conditioning and refrigeration packages based on CO2 technology in high energy-demanding buildings. In this paper, operational parameters and performance data will be presented, related to winter season, thus to heating and domestic hot water service.
Experimental analysis of a CO2 heat pump for instantaneous domestic hot water production
Authors: Trinchieri R , Pieve M , Boccardi G , Calabrese N , Rovella P , Saraceno L 
Published: September 2020

Abstract
The performance of a CO2 (R744) heat pump (HP) depends strongly on the application and on the environmental operating conditions. In particular, the CO2 HP becomes competitive compared to traditional heat pumps using halogenated refrigerants in applications characterized by a high hot water demand (hospitals, sport centres, etc.). This paper deals with the experimental analysis of an air-to-water commercial R744 HP tested in ENEA laboratories for instantaneous production of domestic hot water (DHW). The results show that HP efficiency is strongly affected by the inlet water temperature at the gas cooler. A test equipment capable of maintaining the ambient temperature at a desired value (between -10 °C and +20 °C), and managing water flow and water temperature (between 15 °C and 45 °C) is used to evaluate the machine COP as a function of the boundary conditions (inlet gas cooler water temperature, water flow rate, external ambient temperature). The analysis shows the considerable potential of R744 heat pumps for the instantaneous production of DHW, combining a high performance and relevant energy saving. As well, it points out that, to maximize the COP it is necessary to combine the HP with a high stratification storage system, which ensures a suited inlet water temperature, and with a correct value of water flow.
Buckling Dynamics in Crystalline Membranes
Authors: Pezzutti Aldo D. , Hernández Hugo 
Published: September 2020

Abstract
We study the dynamics of a flexible crystalline membrane with hexagonal pattern. The relaxational dynamics towards equilibrium is described through a Brazovskii-Helfrich-Canham Hamiltonian model. The coupled dynamics between the hexagonal structure and the deformation modifies the elastic properties of the membrane. In this paper, we explore the properties of this coupling by analyzing the structure factor of the deformation out of the plane of the considered membrane system.
Divergence and Flutter of Multilayered Laminated Structures
Authors: Flis J , Augustyn M , Muc A 
Published: September 2020

Abstract
The aim of the present paper is to describe and discuss on possible methods used in the divergence and flutter analysis of composite multilayered laminated structures. Dynamic instability is a very dangerous phenomenon and aeroelastic optimization has become an important element of the composite flight vehicle design process. A special attention is focused on the analysis of cylindrical panels and flat plates using numerical (finite element) methods. The structures with different flow angles, fibre orientations, stacking sequences and boundary condition are considered.
Damage detection in composite structures by multipoint measuring system using guided wave propagation method.
Authors: Stawiarski A , Muc A 
Published: September 2020

Abstract
In this paper, the elastic wave propagation method was used in damage detection in composite cylindrical panels. The multipoint measuring system based on surface-mounted piezoelectric transducers was applied in the multistage measurement of the elastic wave propagation. The damage index definition based on the correlation coefficient was used to determine the state of the structure including localization and estimation of the damage size. Application of the PZT elements as actuators and sensors allows building a low-cost damage detection system that can be used in structural health monitoring (SHM) of composite parts. The resolution of the damage detection results depends on the number and localization of the sensors. However, the application of the multistage wave propagation analysis makes possible to improve the damage detection accuracy without raising the SHM system costs.
Identification of the oculo-motor system based on the Volterra model using eye tracking technology
Authors: Pavlenko Vitaliy D. , Milosz Marek , Dzienkowski Mariusz 
Published: September 2020

Abstract
Instrumental algorithmic and software tools for constructing a nonparametric dynamic model of the human oculo-motor system (OMS) based on its inertial and nonlinear properties are developed in the paper on the basis of the experimental studies data of «input-output» in the form of the Volterra model. Taking into account the specificity of the object investigated, test multistage signals (visual stimulus) were used for identification. Based on the experimental data obtained using the developed computational algorithms and data processing software, a nonparametric dynamic model of OMS in the form of a transition function and transition functions of the 2nd and 3rd orders is constructed. Verification of the constructed model showed its adequacy to the object investigated – a practical coincidence (within the acceptable error) of the object and model feedback for the same test effect.
Piezoelectric Glove Design and Test for Future Wearable Devices
Authors: Ulisse I. , Colaiuda D. , Ricci S. , Ferri G. 
Published: September 2020

Abstract
We present the first results of experimental measurements performed to estimate the available energy derived from the movement of the fingers of one hand. The proposed system consists of a mechanical hand made with a 3D printer, on which 5 piezoelectric strips are applied, electrically connected in series or in parallel. Measurements have shown that the series configuration produces the best result. In this configuration, in fact, the open circuit peak-to-peak voltage reaches 39.6V.
A review of simplified servovalve models for digital twins of electrohydraulic actuators
Authors: Berri P C , Dalla Vedova M D L 
Published: September 2020

Abstract
The development and detail design of complex electrohydraulic actuators for aircraft flight controls require the use of accurate, high fidelity fluid-dynamic simulations in order to predict the behaviour of the system within its whole operating envelope. However, those simulations are usually computationally expensive, and simplified models are useful for the preliminary design phases and real-time health monitoring. Within this context, this work presents a review of low fidelity models for the fluid-dynamic behaviour of an electrohydraulic servovalve. Those are intended to run in real time as digital twins of the physical system, in order to enable the execution of diagnostic and prognostic algorithms. The accuracy of the simulations is assessed by comparing their results against a detailed, physics-based high fidelity model, which computes the response of the equipment accounting for the pressure-flow characteristics across all the internal passageways of the valve.
A first-order lumped parameters model of electrohydraulic actuators for low-inertia rotating systems with dry friction
Authors: Dalla Vedova M D L , Maggiore P , Berri P C , Acquaviva F 
Published: September 2020

Abstract
In aerospace engineering, there are several control systems affected by dry friction, which are characterized by low inertia and high working frequencies. For these systems, it is possible to use a downgraded, first-order dynamic model to represent their behaviour properly without run into numerical problems that would be harmful for the solution itself and would require high computational power to be solved, which means more weight, costs, and complexity. Yet, the effect of dry friction is still possible to be accounted for accurately using a new algorithm based on the Coulomb friction model applied to the downgraded, first-order dynamic model. In this paper, the degraded first-order model is applied to an electrohydraulic servomechanism with its PID control unit, hydraulic motor, electrohydraulic servo-valve, and applied load. These components represent a classic airplane actuator system. The downgraded model will be compared to the second-order one focusing on the pros and cons of the reduction process with a focus on the effect of dry friction for reversible and irreversible actuators.
A Soft Target Risk Application and Threat Analysis Methodology at the Faculty of Applied Informatics in Zlín
Authors: Cajkova Nikola 
Published: September 2020

Abstract
This article is focused on Soft Target Risk and Threat Analysis methodology - and especially on its application at the Faculty of Applied Informatics in Zlín (as a Soft Target). The modern world faces many security problems - and terrorism is one of the biggest. Terrorism became an issue known to the general public due to an attack in the United States on September 11, 2001, also referred to as 9/11. And since then many things have changed. In order to avoid, anticipate and analyse terrorist attacks, several methodologies have been developed, like the Soft Target Risk and Threat Analysis methodology. Each methodology is different, and the advantage of the methodology presented in this article is the consideration of time and space.
Formal verification of Cloud Sisal programs
Authors: Kasyanov Victor N. , Kasyanova Elena V. , Kondratyev Dmitry A. 
Published: September 2020

Abstract
A cloud parallel programming system CPPS which is under development at the A.P. Ershov Institute of Informatics Systems is aimed to support the development, verification and debugging of Cloud Sisal programs and their correct conversion into the efficient code of parallel computing systems for its execution in clouds. In this paper, the methods and subsystems of CPPS intended for formal verification of Cloud Sisal programs are described.
Intelligent Constructing Optimal Airline Seat Protection Levels for Multiple Nested Fare Classes of Single-Leg Flights
Authors: Nechval N. A. , Berzins G. , Nechval K. N. , Danovics V. 
Published: September 2020

Abstract
Airlines sell the same seat at different prices according to the time at which the reservation is made and other conditions. Thus the same seat can be sold at different prices. The problem is to find an optimal policy that maximizes total expected revenue. In this paper, a new intelligent technique of constructing optimal airline seat protection levels for multiple nested fare classes of single-leg flights is proposed. A number of results useful for practical applications are obtained. An illustrative example is given.