bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal perception and satisfaction of Italian students in distance (home) learning vs face-to-face learning environments during the heating season
Authors: Pittana Ilaria , Morandi Federica , Cappelletti Francesca , Gasparella Andrea , Tzempelikos Athanasios 
Published: December 2023

Abstract
During the 2020-2021 COVID-19 pandemic situation, millions of high school students in Italy had to adapt a room in their home for partial distance learning. This paper investigates the thermal perception and satisfaction with the thermal conditions expressed by 45 teenage students alternating between Distance Learning (DL) and Face-to-face learning (FL) during that period. Students completed questionnaires about their perception and satisfaction with the thermal environment while air temperature and humidity were monitored for 14 weeks. The thermal conditions in the classrooms, where students attended classes every other day, were also monitored during this time. The results show that students at home experienced a high percentage of time with conditions outside recommended comfort limits. Nevertheless, most of the students expressed a TSV equal to 0. In addition, the proposed long-term thermal discomfort indicators, such as running mean of the indoor air temperature, correlated rather poorly with subjective votes. This may indicate that different indices should be considered when analyzing mid-term subjective thermal comfort evaluations.
Energy performance of ventilated façades; the influence of the colour and the air channel dimension
Authors: Roig O , Pardal C , Isalgue A , Paricio I 
Published: December 2023

Abstract
Due to the current climate crisis, there is an urgent need to reduce greenhouse gas emissions. Improving façades’ energy performance can significantly reduce the cooling and heating demand of a building. More and more, in warm and mild climates, ventilated façade are given the function of avoiding overheating due to solar radiation and thus reducing the cooling demand of the building. However, this system’s energy performance is not easy to estimate. This study aims to assess the influence of some defining parameters of the ventilated façade on its energy performance. These parameters are not considered in the usual evaluation systems and can be relevant to the envelope’s energy performance. A calculation system has been developed so that architects can use it during the design process to know how their design decisions influence energy performance. Once validated with comparisons with measured values, the calculation system is applied to analyse the influence of some defining parameters of the façade during a warm day in Barcelona: the outer surface’s colour and the dimensions of the ventilation channel. For the studied cases, the change of these parameters implies an important variation in the daily average energy flow traversing the façade. In some cases, it even reverses the direction of the flow, changing from heat gains to heat losses. This concludes that these parameters are relevant to the energy performance of the ventilated façade and that the developed calculation system is a suitable tool to compute it.
Development of a composite model for predicting urban surface temperature distribution in the context of GIS
Authors: Cui Ziang , Leduc Thomas , Rodler Auline , Musy Marjorie 
Published: December 2023

Abstract
In this paper, we present a new model for simulating radiation heat transfer and surface temperatures in urban environments, which is a prerequisite for simulating outdoor mean radiant temperature for pedestrians. We propose a new model whose novelty lies in a new algorithm for simulating diffuse radiation by combining the Nusselt unit sphere method and Monte Carlo ray tracing algorithm. This combined use of different methods is automatically activated depending on the complexity of the scene and, in particular, the arrangement of the facets facing each other. The model is implemented in a Python-based tool, t4gpd, which combines the capabilities of geographic information science and related technologies (GIS &T) with efficient ray-casting solutions. The model is tested on a theoretical mock-up of nine virtual buildings in Nantes under summer and winter weather conditions and compared with SOLENE-Microclimat results. The view factor and solar radiation flux simulation results agree well with the reference solution, with a significant reduction in simulation computation time. However, the model has limitations due to the exclusion of vegetation evapotranspiration characteristics, wind profile model, and soil with complete stratigraphy. Overall, this new model provides an efficient tool for simulating outdoor pedestrian thermal comfort in urban environments and has potential for further development and validation.
Occupant-centric metadata paradigms for comfort optimization in buildings
Authors: Bradford Kipp , Coleman James , Meggers Forrest 
Published: December 2023

Abstract
Three decades of building performance standards have resulted in a meaningful reduction in energy consumption in commercial buildings, but limited improvement in thermal comfort has been observed. ASHRAE Standard 55, the primary reference used to design and operate “comfortable” buildings, specifies six thermodynamic factors that must be addressed to provide comfort in a space. In practice, survey data reports only a small percentage of buildings are considered satisfactory by occupants. We perform a literature review to demonstrate that the range of each of the six thermodynamic dimensions of comfort can be observed well outside of the applicability of ASHRAE 55 in real buildings. The typical practice of modulating air temperature (Ta
) is shown to result in frequent occupant dissatisfaction. We posit that to be able to more consistently operate within a given “comfort zone” in a wider range of thermodynamic environments, we must embed within building systems higher-dimensional, occupant-centric parameters. To understand if two popular metadata schemas, Project Haystack and Brick Schema, are equipped to support higher-dimensional control paradigms, we (1) define a model, measure, manipulate (M3) evaluation criteria, which we (2) apply to each of the above schemas to determine if they can be used to codify closed-loop control for a given set of thermodynamic dimensions of comfort. We conclude that recent extensions to the Brick Schema provide much of the background necessary to codify closed control loops in six dimensions, and that Project Haystack requires a greater expansion.
Binder jetting additive manufacturing comparative study
Authors: Abdelkhalek S 
Published: December 2023

Abstract
This comparative study aims to analyze the most relevant literature regarding Binder Jetting Additive Manufacturing (BJAM) process. The paper starts with section one to briefly introduce the process. Section two of the paper presents an overview of the technology; the main advantages and shortcomings are also addressed. Then, the materials that are mostly employed in BJ are introduced. In section four, the most important design considerations that must be taken into account in this process are presented. Section five of the paper compares the BJ systems available nowadays. Some relevant examples of components and geometries that can be created with this technology are presented next with special emphasis on applications for high-tech industries. Then, the main challenges and limitations along with the prospects of the BJ process are discussed. Finally, the main conclusions extracted from the literature review conducted are listed.
Numerical study of airfoil used for helicopter rotor tip to investigate the enhancement in the aerodynamic characteristics using active flow control at forward flight conditions
Authors: Tawfik T M , Abdelrahman M M 
Published: December 2023

Abstract
Helicopter forward flight is the most important state of flight due to time spent in this mode during the complete helicopter trip. In this study, a main rotor blade tip airfoil was simulated to obtain the effect of applying active flow control on the tip part of the rotor blade. A blowing excitation jet is applied to the leading edge of the airfoil just before the separation point with small momentum and high frequency to enhance the near wall boundary layer characteristic. This jet is used with different amplitude, frequency and excitation location from a leading edge to study the effect of this parameter. A numerical model is used to solve two different angles of attack and all results are compared with NACA report that used the same helicopter hub and airfoil. Results show good agreement with the experimental results and the chosen excitation parameter gives good enhancement to the performance of the airfoil used in the tip part of the helicopter blade in this mode of flight. Performance represented in lift and drag and lift to drag ratio shows improvement, reaching about 10% increase in lift and 30% decrease in drag, which means more than 50% change in lift to drag ratio. Furthermore, this study gives a good estimation of the best excitation location that is required for real application on the helicopter blade to improve of forward flight performance.
Multidisciplinary conceptual investigation for integrating stores, not in the original configuration of a subsonic airplane
Authors: Morad Alaa M 
Published: December 2023

Abstract
Subsonic airplanes are widely used around the world in applications such as pilot training, transportation, sports activities, insect fighting, and field monitoring. This research deals with airplanes that already own the capability of carrying suspended loads. Increasing the airplane’s capabilities and configurations by integrating different suspended loads like smaller or larger external fuel tanks or insecticide tanks that are not in the original configuration of the airplane is a great advantage. This modification can be done without dramatic changes to the airplane and with minimum cost. In this research, a multidisciplinary methodology is used to integrate a commercially-available premade external fuel tank into the Embraer E312 Tucano airplane which is not in the original configuration of the airplane. First, a geometrical analysis is performed to ensure the availability of proper installation. This study leads to the design of an adaptor between the tank and the airplane pylon, then, a computational fluid dynamics (CFD) modeling using ANSYS-CFX is performed to evaluate aerodynamic forces and moments applied on the new fuel tank. Furthermore, finite element modeling using ANSYS-Static structure is performed by applying the aerodynamic and inertial loads to calculate the adaptor’s stresses and structure safety factor. Finally, vibration fatigue analysis-based power spectral densities are developed using ANSYS-Random vibration to calculate the adaptor’s estimated lifetime to ensure the store system’s safety by applying airplane vibration acceleration spectral density pattern selected from applicable standard. In this typical example, the above-mentioned methodology is applied and the results are acceptable.
Improving performance of pump-controlled hydraulic circuits for single-rod actuators: conceptual study
Authors: Imam A , Tolba M S , Sepehri N 
Published: December 2023

Abstract
Pump-controlled hydraulic circuits are more efficient than conventional valve-controlled ones. Pump-controlled hydraulic circuits for double rod cylinders are well developed and, presently, implemented in many applications including aviation. Nevertheless, current pump-controlled hydraulic circuits for single-rod cylinders encounter performance issues during specific operating conditions. Pressure and actuator velocity oscillations are encountered when operating in this critical zone. Different concepts, techniques and designs are proposed by researchers to overcome such vibration issues. In this research, three different concepts to overcome the reported oscillation problem in these circuits are presented; namely: (1) shifting of critical zone into lower loading ranges, (2) applying selective leakage, and (3) applying selective throttling. Simulation studies indicated that the new concepts alleviated the oscillation issue of the common pump-controlled circuits, and improved their performances. The second and third concepts, in particular, were capable of eliminating the whole critical zone. The first concept reduced the area of the critical zone in the load-velocity plane and lessened undesirable effect of oscillations. Simulation studies further proved the enhanced performance of circuits that applies these concepts as compared to previously-designed circuits.
Adaptive dynamic kalman filter for high-performance tilt-angles estimation
Authors: Badawy A A , Abozied M A H , Hassaballa A H , Elhalwagy Y Z 
Published: December 2023

Abstract
Estimation of attitude is a potential task for autonomous vehicles as it directly affects the velocity and position estimates as well as the overall system autonomy. The estimation of attitude angles utilizing gyro measurements always suffers from increasing drift with time. Although accelerometer measurements can provide an absolute estimate of pitch and roll angles for static and low dynamics conditions, they have two drawbacks the effect of additional external acceleration and the inability to capture the high dynamics motion. In this paper, an adaptive Kalman filter (AKF) is utilized for integrating the gyros and accelerometer measurements for enhancing the roll and pitch angles estimates by compensating for the effect of linear acceleration as well as adaptively adapting the Kalman filter measurement covariance matrix. The proposed algorithm is evaluated using real offline measurements for a flying vehicle. Further, a comparative analysis is carried out with the original Kalman filter (KF) algorithm and with the imufilter from Sensor Fusion and Tracking Toolbox from Matlab. The results presented satisfactory performance and enhancement for roll and pitch angles estimate.
Design, modeling, manufacturing, and control of dual axis stabilized system
Authors: Elsepee M M , Roshdy A A , Ali A A , Fayed M A 
Published: December 2023

Abstract
Recently, Inertial Stabilized Systems (ISS) are widely spread either in military or civilian applications. It’s used to stabilize and point the onboard sensors. Therefore, the accurate modeling and control is a crucial factor to design a suitable control system. In this work, two axes gimbal system is designed, modeled, manufactured, and controlled. Firstly, the stabilized system is built using solid work software. Secondly, the system mathematical model is derived for the physical system with its actuators and encoders. Thirdly, the designed model is manufactured and integrated with the suitable motors; the overall open loop system model is implemented in MATLAB (Simulink). Finally, a modified PI-D structure is designed to stabilize the ISS in an efficient manner, the simulation results show the superiority of the designed controller’s performance and robustness compared to the classical PID in transient and steady state responses.
Unified performance parameters for IM/DD techniques over gamma-gamma fading channel with pointing errors
Authors: Roshdy M M , Hassan K M , Elghandour A H 
Published: December 2023

Abstract
In this paper, we discuss the performance of different intensity modulation direct detection techniques (IM-DD) used in free space optical systems (FSO) under different channel impairments such as path loss, atmospheric turbulence, and pointing errors. We derived unified formulas for each of the average symbol error rate (SER) bounds and outage probability for different modulation techniques: OOK, MPPM, and LMPPM. The accuracy of the obtained formulas is validated through comparison with MC-simulation results. Finally, we investigate the effect of system parameters on FSO link performance.
Strength design optimization of sandwich composite structures under heavy dynamic loads
Authors: Osman A , El-Hefni M , Galal K 
Published: December 2023

Abstract
Recent researches have witnessed an increased interest in the Rapid Runway Repair (RRR) methods to rehabilitate damages that may be caused by different incidents, such as: natural disasters of earthquakes, floods or man-made vandalism in civil wars. RRR is a strategic process for airport operations for civil and peace-making missions. The current RRR techniques like precast concrete slabs, metal mats, and fiberglass mats have different pros and cons. The current study numerically investigates CFRP sandwich composite structure for RRR usage, where its strength is maximized by design optimization to reach the possible carrying aircraft wheel capacity and safety factors. The proposed composite structure is advantageous of no corrosion, low erection time, high capacity-to-weight ratio, same finish of runway surface and repaired area, and can be applied over spots of unlevelled or inadequate bearing capacity of 60 cm diameter. The strength of the basic design of composite sandwich structure is first assessed to its maximum allowed carrying aircraft wheel capacity by FE modelling. Secondly, The Genetic Algorithm (GA) optimization technique is applied for maximizing the strength of the composite structure webs satisfying the minimum safety factor of five failure criteria of Tsai-Wu, Tsai-hill, Hoffman, Hashin and maximum stress. Finally, the achieved results promoted the usage of the composite structure to operate at the taxiways, runways, and theoretically, landing and take-off areas.
Using remote sensing technology in estimating flood discharge
Authors: Abdullah A S , Moussa O M , Hassan A A , Tarek M 
Published: December 2023

Abstract
Floods are the most natural disasters occurring on earth. Recently, Egypt has been subjected to more frequent floods due to climate change. The main objective of this paper is creating hydrological analysis and estimating water discharge due to a flood hitting a hazardous zone near Safaga city. The research is divided into four main stages; 1) Morphological study, 2) Meteorological study, 3) Losses estimation, and 4) Flood discharge estimation. First, morphological study in which watershed boundaries, main streams and morphological data are delineated using geographic information system (GIS) with the aid of Landsat-8 satellite images and 30-m resolution digital elevation model (DEM). Second, meteorological study in which conventional rainfall frequency analysis is generated to estimate rainfall depth at different return periods using 15-years rainfall historical data from weather stations. Third, losses estimation is determined by using soil conservation service-curve number method (SCS-CN). Fourth, water discharge volume is carried out through hydrological modelling using a hydrologic engineering centre model. The estimated water volume is an appropriate information for decision makers to propose the adequate protection works to mitigate flood impacts.
Propulsion theoretical and experimental analysis of composite propellants motors
Authors: Said A , Maraden A , Elhedery T M , abd Elall A M , Elbasuney S 
Published: December 2023

Abstract
Rockets have revolutionized space technology and human space exploration. Most rockets and missiles are both propelled by rocket motors that use composite solid propellants. The ICT code and the NSAS CEA code are two programs that can be used to forecast theoretical propulsion parameters for composite solid rocket propellant. Rocket propellant performance is governed by a specific impulse factor, which is calculated theoretical and experiment. In this paper, the theoretical specific impulse for different composite solid propellant formulations at 70 bar combustion pressure and an adapted nozzle (optimum expansion) were calculated by the NASA-CEA code and the ICT code. Meanwhile, a static firing test was performed on a small scale test motor to experimentally determine the actual specific impulse. The objective is to verify theoretical calculations from two codes with experimental data, via the determination of the specific impulse deviation co-efficient.
Governing of a Francis Turbine Model Subjected to Load Variations
Authors: Haugum Jørgen 
Published: December 2023

Abstract
In this work, the problem of mechanical backlash in the governor system for the Francis test rig at the Waterpower Laboratory, NTNU Trondheim, is investigated. Through numerical simulations on a digital model of the test rig, done in the software SIMSEN, the maximum allowable backlash which still enables stable governing was detected. This was done by further developing the model used in the work by A. Ingranata [1], to perform load variation tests presented by Statnett [2]. From these frequency control tests it was concluded that the maximum mechanical backlash which still enables stable governing, is 1% of maximum stroke length of the servomotor present in the governor system. To design a system which can achieve the requirements of 1% backlash, a more conventional layout which utilizes links instead of the slots present in the existing governor ring, is suggested.
A Review on Machine Learning approaches for Himalayan Rock Mass Classification
Authors: Dumaru Jenisha , Karki Sujan , Shrestha Ranjit , Khadka Shyam Sundar 
Published: December 2023

Abstract
Among all of the subsystems and components of hydropower, the tunnel is one of the crucial structures that face most of the pre-operation, real-time and post-operation challenges. Tunnels used as a water conveyance system in the majority of the projects lead to significant importance in the hydropower sector. The engineering rock mass classification is a crucial step in the accomplishment of underground constructions, particularly tunnels and caverns within the rock mass. The quality of rock mass parameters must be assessed and predicted with greater accuracy. However, the difficulties lie in the proper assessment of these parameters to define their quality. Studies have shown that despite the use of numerical and empirical methods in construction practices, numerous problems are reported when it comes to dealing with such structures. Over the years, various approaches based on machine learning (ML) techniques have been used for the minimization of these difficulties. As in recent trends, the development of machine learning technologies is currently bringing new methodologies in assessing rock mass classification. Although, because a sufficiently large database is required for such initiatives, there are a number of difficulties in their practical execution. Thus, a review of studies on the use of machine learning techniques in rock mass classification is presented in this paper. To determine the future directions of ML in RMC, it presents a comprehensive assessment to examine how ML models are being used. This study offers recommendations for creating an industry-specific model focusing on the strengths and weaknesses of ML techniques