bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sequentially coupling LBNL-method and Modelica to model and operate adaptive facades with inhomogeneous printing patterns
Authors: Weber Simon Oskar , Fang Yuan , Park Sumee , Leistner Philip 
Published: December 2023

Abstract
In this work, two U- and g-value Modelica models of a three-layer membrane construction with inhomogeneous stripe pattern were set up. Thus, a simple ISO 52022 model is compared with a detailed model with Modelica integration of Klems-Matrices by LBNL method calculation. For the U-value, both models equally predict the heat transmission. For the g-value, the detailed model shows an strong angular behavior depending on the stripe pattern, the layer distances. Compared to a reference glazing, the application of an adaptive operating strategy results in a reduction of the total energy consumption by up to 27%. Depending on the operation strategy the heating energy increases between 33-100% and cooling energy decreases by 50-80%. This is mainly due to the lower g-value with the detailed model. The actuation energy required for this can be neglected. The resulting reductions in heating and cooling energy exceed the actuation energy by several orders of magnitude.
Impact of different thermal zone data simplification for model calibration on monitored-simulated performance gaps
Authors: Chiesa G , Fasano F , Grasso P 
Published: December 2023

Abstract
The paper analyses the impact of different simplification approaches for model verification purposes considering a reference demo case of a municipality school located in Torre Pellice (Italy), which has been monitored with room detail since April 2021. The target variable of the calibration process is the indoor air temperature: firstly, results validity is checked on an unoccupied free-running period; secondly, occupied standard behaviours and adapted to real-use ones are adopted to test the simplification choices impact on indoor thermal comfort indicators (e.g. the Adaptive Comfort Model). Several model simplification actions on both building-level construction and zoning approaches are considered. Results of this demo case demonstrate the usability of simplified models, which can be adopted instead of more detailed and time-consuming full models for performance gap detections and other analyses.
Green roof energy performance in different climate zones: a simulation study
Authors: Kulumkanov Nursat , Nadeem Abid , Tokbolat Serik 
Published: December 2023

Abstract
Green roofs are widely used as a passive building design technique to decrease the cooling demand in buildings. The vegetation uses the energy of the surroundings during the evapotranspiration process, leading to a temperature decrease in air. This paper investigates the effectiveness of green roofs in 45 cities in different climate zones. The simulation of the energy performance of buildings is performed using DesignBuilder software, which integrates the EnergyPlus engine. The results show that green roofs effectively reduce the cooling load but increase heating energy consumption. The highest performance in total energy savings was in the arid zone with savings ranging from 3.2% to 9.1%, despite having a high heating demand. Tropic and temperate zones show relatively lower results, which vary from 1.4% to 4.1% and -0.2% to 4.2%. The cold zone shows the worst result, ranging by around 1%. Thus, green roofs show better performance in cities with high-temperature ranges, direct radiation, and humidity level.
Experimental characterization and modal analysis for woven composite high aspect ratio beam
Authors: Osama M , Ahmed M Y , Khalil M , Saleh S 
Published: December 2023

Abstract
In modern engineering applications such as aerial vehicles, composite structures are widely implemented due to their high structural stiffness and very low weight-to-lift ratio. They also enable designers to control their mechanical properties as well as the manufacturing method and fabrication quality to achieve the required structural performance. However, various manufacturing methods and the fabrication process can be considered production imperfections. In this study, an assessment of the fabrication quality for a typical composite structure is implemented. As considered for airplane wings and helicopter blades, a high aspect ratio structure is implemented as a case study. This structure is composed of laminated woven carbon fiber/epoxy resin fabricated using the vacuum bagging production method. To characterize the mechanical properties of the proposed structure, a mechanical tensile test is carried out. An experimental modal analysis via roving hammer test is implemented to examine the dynamic behavior of the proposed structure. To assess the quality of manufacturing and fabrication quality, the obtained natural frequencies are compared with the ones computed using a numerical technique using the Finite Element Method (FEM). The analytical problem using MATLAB had been established to emphasize the experimental results. Results showed that good manufacturing quality is achieved by using the vacuum bagging production method. Also, the experimental results agree well with both the numerical and theoretical results, Which indicates good manufacturing quality.
Simulation of tilt-rotor UAV flight dynamics in horizontal flight
Authors: Ibrahim Noureldein A , Zakaria Mohamed Y , Kamal Ashraf M 
Published: December 2023

Abstract
Tilt-rotor unmanned aerial vehicles (UAV) have gained significant importance in the aeronautical industry due to their ability to transition between vertical and horizontal flight. One of the important steps in the development of such UAVs is to assess their performance and stability characteristics. Simulation of flight dynamics is an essential tool that enables the designers to test and optimize the flight characteristics of these UAVs. This paper presents a complete procedure for developing a 6-degree-of-freedom flight dynamics model of a tilt-rotor UAV in fixed-wing mode using a physics-based modeling approach. All necessary sub-models are developed and integrated into the Simulink simulation environment to allow for predicting the UAV’s dynamic response. The developed model is verified for correct operation by simulating horizontal steady-level flight and exciting its natural longitudinal modes.
Experimental investigation of the effects of diesel-bioethanol blends on combustion and emission characteristics in industrial burner
Authors: Elkelawy M , Bastawissi H A , Abdel-Rahman A K , Abou-elyazied A , El-malla S 
Published: December 2023

Abstract
The increased rate of industrialization in various countries has increased the demand for fossil fuels, which are found in limited reserves and in specific countries. As a result, countries that lack these energy resources are experiencing an energy crisis. As a result, alternative fuels that are made locally within countries are needed, like alcohol.. Experiments were carried out in this research to examine the combustion and emission characteristics of diesel and bioethanol blends using an industrial 350 KW burner. Three different diesel/bioethanol ratios (DE-10, DE-15, and DE-25) were tested. Flame geometries, temperatures, and emissions for diesel/bioethanol blends were measured experimentally for each type of fuel to obtain a complete characterization of the combustion processes. The findings showed that an increase in the percentage of bioethanol in the fuel blends for DE-10, DE-15, and DE-25 reduced CO, UH, NOx, and soot emissions (by around 20%, 40%, and 45%), (by about 13%, 25%, and 43%), (by about 8%, 14%, and 22%), and (by about 16%, 33%, and 50%), respectively, compared to neat diesel combustion. However, because bioethanol has a lower heating value than diesel, As bioethanol percentages increased in the fuel mixture, exhaust temperature and maximum flame temperature decreased.
Spacecraft fault detection and identification techniques using artificial intelligence
Authors: Abdel Aziz T S , Salama G I , Mohamed M S , Hussein S 
Published: December 2023

Abstract
The complexity of spacecraft systems and their missions is increasing, requiring higher levels of performance and innovative solutions. It is essential to have onboard autonomy with minimal faults to ensure reliability, availability, and safety. Fault Detection and Identification (FDI) is critical in identifying spacecraft faults before they cause major failures. However, FDI design and application are challenging due to the space environment and the reliance on system information. To improve accuracy, speed, and noise robustness, modern FDI methods based on Artificial Intelligence (AI) techniques have been developed. This paper investigates the latest FDI techniques in the spacecraft attitude determination and control subsystem (ADCS) and electrical power subsystem (EPS). The article discusses various FDI methodologies and frameworks, highlighting their advantages, drawbacks, and the significance of AI implementation. Additionally, the paper presents a thorough analysis and comparison of the different methods.
Modeling and analysis for reaction control thruster used for station-keeping maneuvers of a GEO satellite
Authors: Ashraf M K , Hendy H , Sallam A F , Ashry M M , Elhalwagy Y Z 
Published: December 2023

Abstract
This paper introduces a theoretical description, force, and torque analysis of a Reaction Control Thruster (RCT) used as an actuator in Attitude Determination and Control Subsystem (ADCS). Mathematical formalization, realization, and implementation are offered to implement the RCT model using Matlab-Simulink. Furthermore, this paper proposes an accurate RCT Simulink model to control the orientation and stabilizes the Geostationary Earth Orbit (GEO) satellite within its orbit. Finally, a comparative analysis is carried out with an existing satellite platform (Eurostar-3000) based on the Root Mean Square Error (RMSE) for the delta velocity (delta-𝒱) parameter. The outcomes of the model simulation validated the effectiveness of the proposed approach.
Flexible harmonic domain model of solar PV supply system
Authors: Abdo M , Abdel-Rahman M A , Amer M , Helmy S 
Published: December 2023

Abstract
This paper presents a flexible harmonic domain (FHD) model of a grid-connected solar PV system amenable to harmonic analysis. The system consists of a 4.12 kW solar photovoltaic array that provides supply continuity and reliability for unmanned aerial vehicle (UAV) ground control station. The proposed system consists of a solar array, a boost converter, a three-phase inverter, and a three-phase filter. FHD technique is used to model the system, as it accounts only for dominant frequencies which enables obtaining of compact yet precise description of the system’s harmonic interactions. Compared to complexity, extra harmonic extraction routines, and large computational resources of the time domain technique (TD), FHD needs only one matrix inversion to obtain both the voltage/current waveforms and harmonic content of each part of the system. The obtained results prove the feasibility, accuracy, and simplicity of the proposed FHD technique for modeling switched devices while maintaining the computational resources. For each part/state of the proposed system, both the waveform and its harmonic content are visualized.
A new mathematical model to evaluate the effect of load inclination on aircraft shelter’s foundations
Authors: Elhanash M , Elsherif A K , Zaky H N , Nagy N M 
Published: December 2023

Abstract
Aircraft shelter is a structure or a reinforced hanger that has many uses in military aspects. It is used to protect military aircraft from different dangers such as enemy chemical attacks. Also, it provides housing, permitting aircraft maintenance and it can be storage for different weapons. therefore, optimum design of aircraft shelter is of a great importance. It may take several shapes to be suitable for its usage. It can be made from concrete, steel or composite materials. The foundations of an airplane shelter must be designed as best as possible. Design objectives are greatly impacted by the contact pressure between the earth and the foundation surface. Classical method in design assumes maximum uniform linear distribution of pressure under contact surface of footing. So, considering real contact pressure has a great interest for many authors. In this article, a new analytical method is proposed to study the effect of moments and load inclination on the design of rectangular isolated footing. The model proposed takes into consideration the real soil pressure. A parametric study was conducted and data obtained from classical model were larger than those from proposed model. Seven Rectangular isolated footings were designed using traditional method and proposed method. The proposed method is more economic since it provides less concrete dimensions. Results obtained from the new model were compared with FEM and achieved reasonable agreement.
Enhancing airport runways performance using composite systems numerically using unit cell concept.
Authors: Abdelaziz A. M. , Elshesheny Ahmed , Abdelmotaal Nabil , Nagy Nabil M. 
Published: December 2023

Abstract
One of the problems, which would affect airport runways is the settlement of soil. Such settlement would be controlled by enhancing the performance of the soil underneath the airport runway. The composite system consists of graded stone-reinforced soil and reinforcing layers. This system is defined as stone column, which is widely used to improve weak soils as one of the soil stabilization methods due to its simple construction and economic cost. It is used to reduce settlement and enhance soil-bearing capacity. By using such technique, part of the high-compressibility and low-shear strength soil is replaced with coarse filler materials with high-shear strength and extremely low compressibility. In this study, a 3D numerical model of a unit cell is created to examine the impact of changing the controlling parameters in the model, i.e. spacing between columns (S), weak soil cohesion (c), and angle of internal friction for stone column material (φ). It was established that the use of stone columns improves the soil-bearing capacity and reduces settlement, strengthening the stability of airport runways. The efficiency of the system is improved by increasing the column material’s internal friction angle and the cohesion of the surrounding soil. The ultimate bearing capacity of soil without SC and SC-soil systems were 150 kPa, and 460 kPa, respectively, which illustrates that the bearing capacity was increased by 306.7%.
Challenges with onboard strain measurements on a model Francis turbine runner
Authors: Kverno Johannes , Vefring Gaute Elde , Iliev Igor , Solemslie Bjørn Winther , Dahlhaug Ole Gunnar 
Published: December 2023

Abstract
As the world transitions towards more renewable energy sources, as a step to reduce the emissions of CO2, intermittent and non-dispatchable sources like solar and wind will take up a larger proportion of the energy production. With more unregulated power in the energy mix, a higher demand is put on the rest of the energy production system. Hydropower is in a unique position as it is both renewable and a highly flexible energy source. The increased use of flexible operation of Francis turbines especially, puts a higher dynamic load on the runner components which as a consequence leads to a reduced lifetime. In this paper we present the experimental setup and results from a measurement campaign performed on a model of a low specific speed Francis runner. Onboard measurements with strain gauges at the trailing edge of two runner blades were performed. The experiments were conducted as a part of the HydroFlex project with the goal of validating numerical simulations and to gain a better understanding of the reduction of lifetime on Francis turbines due to higher fatigue loading from more flexible operation. The results shows that there were a significant drift of the mean strain over time during the measurement campaign, and a lower measured strain at BEP than expected when compared to numerical simulations. In this paper, the experimental setup, results and challenges encountered are presented.
Numerical Analysis of Francis Turbine being operated in variable speed from sediment erosion perspective
Authors: Ghimire Amul , Kayastha Atmaram , Bijukchhe Pawan Lal , Chitrakar Sailesh , Neopane Hari Prasad 
Published: December 2023

Abstract
Sediment erosion in hydro turbines is one of the most daunting reasons incurring huge losses to power plant owners located in the Hindu Kush Himalayan region. Repetitive repair and maintenance of runners of Francis turbines installed in such power plants have been one of the major contributor to these losses. There is no measure of how much these power plant owners have lost due to reduction in efficiency brought about by the eroded surfaces of runners. Amidst several optimizations performed in changing the runner design, this study has been conducted to study the applicability of the pre-existing designs being operated in variable speed conditions, irrespective of its practical difficulties. Numerical simulations have been performed to determine the sediment erosion of the runners at different operating conditions. In addition to the guide vane angles, and the amount of sediment injected into the system; which is parametrized as a function of the guide vane angles; rotational speed of the runner has also been varied. Complete efficiency hill diagram and sediment erosion hill diagram have been developed to analyse the efficiency and sediment erosion at several operating conditions. Finally a comparison of the variations in efficiency and sediment erosion upon operating the turbine in synchronous speed and variable speed modes have been shown. Basically, the efficiency of the turbine and sediment erosion on blade surface can be increased and decreased respectively, at off design conditions by operating the turbine in variable speed.
Design and Fabrication of Automatic Voltage Stabilizer using Relay-Based Tap Changing of Transformer
Authors: Chaudhary C , Kshetri A , Shrestha A , Bista A , Bista D 
Published: December 2023

Abstract
The growing demand for power, and fluctuations in the load present challenges for maintaining a stable and continuous voltage supply. A voltage stabilizer is an electrical appliance that is designed in such a way that it delivers a constant output voltage regardless of the variation in the input supply voltage. This research explores various measures aimed at stabilizing the voltage supply in the face of increasing power demand and fluctuations in load, to ensure a constant output voltage. To this end, a microcontroller-based Automatic Voltage Stabilizer is presented as a robust solution. A prototype of the device, with a power rating of 1kVA and operating at a frequency of 50 Hz, has been fabricated and includes components such as an autotransformer, relay board, voltage sensors, and an Arduino microcontroller. The autotransformer’s taping is adjusted in response to changes in the input voltage. Experimental results show that the prototype can effectively regulate the voltage output between 190V to 250V under a load of 300W.
Review of Industrial Heating and Potential Low-carbon Fuels in the Context of Nepal.
Authors: Ghimire A , Pandey B , Ghimire R , Thapa B S 
Published: December 2023

Abstract
Process heating is an important step in manufacturing industries such as metal, cement, brick, food, etc., and accounts for a large share of the total energy consumption of those industries. In Nepal, process heating alone accounts for around 64% of the process energy of the manufacturing sector. Around 64% of Nepalese industries’ energy demand for process heating is supplied by high-carbon emitting fossil fuels such as coal, diesel, etc. The industrial sector is responsible for significant global greenhouse gas emissions. Nepalese manufacturing Industries emit around 0.002248 GT of CO2 annually. The movement toward carbon neutrality has prompted many countries around the world to look for clean and sustainable fuel to meet their decarbonization goal. This study overviews Nepalese industries’ different industrial heating processes in terms of energy consumption, emissions, energy efficiency measures and interventions, and renewable options from a literature review and using data from secondary sources. Based on the data collected and the literature review of the industries, the potential low-carbon fuels which can be compatible with heating applications in Nepalese industries are reviewed. This paper concludes with recommendations for the future decarbonization of process heating in Nepalese industries.
Evaluating natural degassing in a river to create a baseline for comparison to technical degassing methods.
Authors: Ludwig Kuhn W. , Solemslie Bjørn Winther , Hihn Jean-Yves , Dahlhaug Ole Gunnar 
Published: December 2023

Abstract
In Norway, a recent project used a risk matrix to identify about 200 hydropower plants ( 11 % of the total number) of being in high risk of producing air-supersaturated water. The combined installed capacity of these hydropower plants amounts to more than 45 % of Norway’s total installed hydropower capacity. Total dissolved gas (TDG) supersaturation in water is, dependent on the actual saturation value and the duration of the occurrence, lethal to certain types of fish and aquatic invertebrates. Natural degassing is highly dependent on the morphology of the downstream water system, but tends to be insufficiently slow with regard to lethality of TDG supersaturation. The Brokke power plant in southern Norway is known to create TDG supersaturation. Since 2012, continuous monitoring of the TDG level happens at the power plant outlet and several positions in the Otra river downstream. Measurement data has been evaluated and a method has been developed to calculate the liquid-gas mass transfer coefficient kLa as an indicator for the natural degassing efficiency within certain stretches of the river using assumptions for the river’s geometry. The results are in agreement with former evaluation of the measurements. At the Waterpower Laboratory at NTNU in Trondheim, Norway, a test rig has been designed and instrumented to prove the effectiveness of degassing methods. An in-house pressure system is used to produce air-supersaturated water, which is then channeled through an open flume. At the flume’s inlet, the degassing mechanism is installed. The TDG levels are monitored both upstream and at downstream the degassing device. The kLa will be used to compare natural degassing in the river downstream Brokke power plant to the experimental degassing methods in the Waterpower Laboratory.