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"Cold Experiments."
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Experiments with heat and cold
Presents several experiments with heat and cold and discusses thermodynamics.
BOOK
Wind Speed Measurement by an Inexpensive and Lightweight Thermal Anemometer on a Small UAV
Profiling wind information when using a small unmanned aerial vehicle (sUAV) is vital for atmospheric profiling and monitoring attitude during flight. Wind speed on an sUAV can be measured directly using ultrasonic anemometers or by calculating its attitude control information. The former method requires a relatively large payload for an onboard ultrasonic anemometer, while the latter requires real-time flight log data access, which depends on the UAV manufacturers. This study proposes the feasibility of a small thermal anemometer to measure wind speeds inexpensively using a small commercial quadcopter (DJI Mavic2: M2). A laboratory experiment demonstrated that the horizontal wind speed bias increased linearly with ascending sUAV speed. A smoke experiment during hovering revealed the downward wind bias (1.2 m s−1) at a 12-cm height above the M2 body. Field experiments in the ice-covered ocean demonstrated that the corrected wind speed agreed closely with the shipboard wind data observed by a calibrated ultrasonic anemometer. A dual-mount system comprising thermal anemometers was proposed to measure wind speed and direction.
Journal Article
Cool experiments with heat and cold
Reading about heat and cold is just the tip of the iceberg. This book lets readers create their own icebergs! Hands-on activities make learning about heat and cold both tangible and fun. Simple explanations help readers grasp complex concepts while step-by-step instructions and accompanying photographs ensure they will master each experiment.
Book
ANN-Based Reliability Enhancement of SMPS Aluminum Electrolytic Capacitors in Cold Environments
Due to their substantial energy density and economical pricing, switching-mode power supplies (SMPSs) often utilize electrolytic capacitors. However, their ability to function at low temperatures is essential for dependable operation in several sectors, including telecommunications, automotive, and aerospace. This study includes an experimental evaluation of how well standard SMPS electrolytic capacitors operate at low temperatures. This paper investigates the suitability of standard electrolytic capacitors used in switched-mode power supplies (SMPSs) for low-temperature applications. The experimental evaluation exposed the capacitors to temperatures ranging from −5 °C to −40 °C, assessing capacitance (Cp), impedance (Z), dissipation factor (DF), and equivalent series resistance (ESR) at each temperature. The capacitor’s time-domain electrical signals were analyzed using the Pearson correlation coefficient to extract discriminative features. These features were input into an artificial neural network (ANN) for training and testing. The results indicated a significant impact of low temperatures on capacitor performance. Capacitance decreased with lower temperatures, while the ESR and leakage current increased, affecting stability and efficiency. Impedance was a valuable diagnostic tool for identifying potential capacitor failure, showing a 98.44% accuracy drop at −5 °C and 88.75% at the peak temperature, indicating proximity to the manufacturer’s specified limit. The study suggests further research and development to improve the performance of electrolytic capacitors in SMPS systems under cold conditions, aiming to boost efficiency and reliability.
Journal Article
How hot is hot? : science projects with temperature
Provides instructions for doing experiments involving temperature using items found around the house.
Book
Vertical Section Observation of the Solid Flow in a Blast Furnace with a Cutting Method
The solid flow plays an important role in blast furnace (BF) ironmaking. In the paper, the descending behavior of solid flow in BFs was investigated by a cold experimental BF model and numerical simulation via the discrete element method (DEM). To eliminate the flat wall effect on the structure of solid flow in lab observations, a cutting method was developed to observe the vertical section of the solid flow by inserting a transparent plate into the experimental BF model. Both the experimental and numerical results indicated that plug flow is the main solid flow pattern in the upper and middle zones of BFs during burden descending. Meanwhile, a slight convergence flow and a deadman zone form at the lower part of the bosh. In addition, the boundary between the plug flow and convergence flow in BFs was determined by analyzing the velocity of the burden in vertical directions and the Wilcox–Swailes coefficient (Uws). The results indicated that the Uws can be defined as a critical value to determine the solid flow patterns. When Uws ≥ 0.65, the plug flow is dominant. When Uws < 0.65, the convergence flow is dominant. The findings may have important implications to understand the structure of the solid flow in BFs.
Journal Article
Flow zone distribution and mixing time in a Peirce—Smith copper converter
Peirce—Smith copper converting involves complex multiphase flow and mixing. In this work, the flow zone distribution and mixing time in a Peirce—Smith copper converter were investigated in a 1:5 scaled cold model. Flow field distribution, including dead, splashing, and strong-loop zones, were measured, and a dimensionless equation was established to determine the correlation of the effects of stirring and mixing energy with an error of <5%. Four positions in the bath, namely, injection, splashing, strong-loop, and dead zones, were selected to add a hollow salt powder tracer and measure the mixing time. Injecting a quartz flux through tuyeres or into the backflow point of the splashing wave through a chute was recommended instead of adding it through a crane hopper from the top of the furnace to improve the slag-making reaction.
Journal Article
Urukul – Open-source Frequency Synthesizer Module for Quantum Physics
We describe Urukul, a frequency synthesizer based on direct digital synthesis (DDS), optimized for wave generate control in atomic, molecular and optical (AMO) physics experiments. The Urukul module is a part of the Sinara family of modular, open-source hardware designed for the ARTIQ quantum operating system. The Urukul has 4-channel, sub-Hz frequency resolution, controlled phase steps and accurate output amplitude control. The module is available in two population variants. This paper presents Urukul module construction and obtained characteristics.
Journal Article
Surface Pressure Measurement of Truncated, Linear Aerospike Nozzles Utilising Secondary Injection for Aerodynamic Thrust Vectoring
A cold-gas test campaign has been conducted at the DLR’s P6.2 test bench in Lampoldshausen, with the objective of investigating the linear aerospike nozzle flow in interaction with secondary injection thrust vector control (SITVC). In this campaign, the influence of nozzle truncation, injection position and injection pressure on the nozzle surface and base pressure is analysed using pressure probes and Schlieren flow-visualisation techniques. The effects of injection position and truncation on the nozzle surface pressure development are comparable for all geometric variations, resulting in a locally increased static pressure upstream and a locally decreased static pressure downstream of the injection. The magnitude and dimension of these high- and low-pressure regions are correlated with the injection pressure. However, the influence of injection position and truncation on the base pressure is not entirely predictable by the named parameters, indicating an interdependence between both geometric parameters. Finally, the required pressure ratio of injection to the primary flow to ensure sonic injection has been analysed on TUD’s cold-gas test bench. This allows the respective injection position-dependent threshold to be identified. The analysis reveals that these experiments have been conducted under transsonic injection conditions.
Journal Article