Browse Topic: Gases
Imagine a robot that can walk, without electronics, and only with the addition of a cartridge of compressed gas, right off the 3D printer. It can also be printed in one go, from one material.
A long-lasting, 3D-printed, adhesive-free wearable provides a more comprehensive picture of a user’s physiological state. The device, which measures water vapor and skin emissions of gases, continuously tracks and logs physiological data associated with dehydration, metabolic shifts, and stress levels.
The race is on for leadership in cislunar space, considered a gateway to the future of space exploration. Yet operating in this domain introduces unique challenges for propulsion systems. In contrast to low-Earth orbit (LEO), the cislunar environment requires higher precision propulsion solutions; these are necessary to enable rapid and accurate maneuvering of spacecraft and long-term sustainability. Propellants like hydrazine and nitrogen tetroxide offer the high energy density required for cislunar missions, but they must be handled very differently from the inert, non-reactive gases at play in LEO systems.
Plasma is a state of matter, like a solid, liquid, or gas. When sufficient energy is applied to a gas, it becomes ionized, transitioning into the plasma state. With precise application and control, plasma can alter surface properties of a metal or plastic part without compromising the underlying material.
NASA's Cryogenic Flux Capacitor (CFC) capitalizes on the energy storage capacity of liquefied gases. By exploiting a unique attribute of nano-porous materials, aerogel in this case, fluid commodities such as oxygen, hydrogen, methane, etc. can be stored in a molecular surface-adsorbed state. This cryogenic fluid can be stored at low to moderate pressure densities, on par with liquid, and then quickly converted to a gas, when the need arises. This solution reduces both safety-related logistics issues and the limitations of complex storage systems.
LIDAR-based autonomous mobile robots (AMRs) are gradually being used for gas detection in industries. They detect tiny changes in the composition of the environment in indoor areas that is too risky for humans, making it ideal for the detection of gases. This current work focusses on the basic aspect of gas detection and avoiding unwanted accidents in industrial sectors by using an AMR with LIDAR sensor capable of autonomous navigation and MQ2 a gas detection sensor for identifying the leakages including toxic and explosive gases, and can alert the necessary personnel in real-time by using simultaneous localization and mapping (SLAM) algorithm and gas distribution mapping (GDM). GDM in accordance with SLAM algorithm directs the robot towards the leakage point immediately thereby avoiding accidents. Raspberry Pi 4 is used for efficient data processing and hardware part accomplished with PGM45775 DC motor for movements with 2D LIDAR allowing 360° mapping. The adoption of LIDAR-based AMRs
R-1234yf is used in almost every new car sold in the U.S., but the EU is discussing a ban and the industry is investigating alternatives like CO2 and propane. According to its manufacturer, Chemours, use of R-1234yf has grown so much since the refrigerant replaced the long-established R-134a that it's now used in 95% of new cars sold in the U.S. An estimated 220 million cars on global roads are also using it. The problem with R-134a, which came in cars and trucks in the 1990s, is that it's a gas with “a global warming potential (GWP) that is 1,430 times that of CO2,” according to the EPA. Since 2017, EU legislation has banned the use of any refrigerant in new vehicles with a GWP higher than 150. That rule doomed R-134a but opened the door for R-1234yf, which has a GWP of only four. The EU is currently revisiting R-1234yf emissions rules and may ban the substance in a few years. In the U.S., the EPA stands by its use.
Details of combustion — the chemical reactions that take place when, for example, a flame is lit — are fleeting and therefore, difficult to study. But scientists would like to better understand the complex processes that occur in those billionths of seconds, not only to make engines more efficient but also to shed light on how candle flames, cars, and airplanes produce gases and particles that are harmful to humans and the environment.
Ultrasound imaging and ultrasound-mediated gene and drug delivery are rapidly advancing diagnostic and therapeutic methods; however, their use is often limited by the need for microbubbles, which cannot transverse many biological barriers due to their large size. A team of researchers from Rice University have introduced 50-nm gas-filled protein nanostructures derived from genetically engineered gas vesicles(GVs) that are referred to as 50 nmGVs.
American drivers have long been accustomed to quickly filling up at a gas station with plenty of fuel available, and electric vehicle drivers want their pit stops to mimic this experience. Driver uncertainty about access to charging during long trips remains a barrier to broader EV adoption, even as the U.S. strives to combat climate change by converting more drivers.
To understand effect of thermal hazards of LIBs during TR event, it is important to study flame propagation behaviour of LIBs during storage and transport applications. The process of flame propagation involves complex phenomena of gas phase behavior of LIBs. Present paper attempts a numerical investigation to portray this complex phenomenon. This paper investigates 18650 lithium cell considering two different chemistries NMC and LFP. A 3D numerical CFD model has been constructed to predict the gas phase behavior, threshold internal pressure, and cell gas venting of an 18650-lithium cell under thermal runaway conditions. The gas phase processes are modelled using the 4-equation thermal abuse model, while the cell's venting mechanism is modelled using Darcy's equation. Present work is divided into two parts: 1) Venting gas Internal pressure prediction 2) modeling thermal runaway event. Both procedures are implemented on two different cell chemistries to understand and evaluate following
If an external force with changing amplitude acts on an elastic medium such as a gas, a liquid or a solid, an undulating propagation of pressure and density fluctuation occurs in space and time, starting from the point where the force is applied. This is known as sound. The frequency of sound waves ranges from a few hertz (Hz) up to several gigahertz (see Figure 1). Infrasound, the sound humans cannot hear, lies at frequencies below 16 Hz. It is followed by the hearing range, which reaches up to 20 kHz. Ultrasonic waves, which cannot be heard, lie in the frequency range from 20 kHz to 1.6 GHz, which equals 16 billion cycles per second. A prominent application example in medical technology is the use of ultrasound for diagnostic imaging techniques. In industry and research, ultrasound is mainly used in measurement technology, where sound waves with low power are used. The intensity of the sound describes the power that hits a certain surface. If it exceeds 10 W/cm2, we speak of power
The study demonstrates the possibility and in particular the method to derive the efficiency of the entire fuel cell power system by measuring specific data of the recirculation path of the anode circuit of a fuel cell system. The results demonstrate the capabilities of the existing test rig and enable investigations on the suitability of auxiliary components. This study focuses on the hydrogen recirculation path equipped with multiple sensors and a needle valve to enable the required operating conditions of the fuel cell. Running a startup load profile without reaching the equilibrium state at all steps, the dynamic of the system and the requirements to the sensor parameters, such as sampling rate and precision, was seen. Additionally, it became obvious that the recirculation pump used is oversized, but a load point shift compensated this artifact. In detail, the stoichiometry and the efficiency of the entire system was evaluated. It was seen that the hydrogen concentration is
Water removal from Proton Exchange Membrane (PEM) Fuel Cell (FC) mainly involves two phenomena: some of the emerging droplets will roll on the Gas Diffusion Layer (GDL), others may impact channel walls and start sliding along the airflow direction. This different behaviour is linked to the hydrophobic/hydrophilic nature of the surface the water is moving on. In this paper, the walls of the channel of a FC were characterized by applying optical techniques. The deposition of droplets on the channel wall led to an evaluation of the proper range for Contact Angle Hysteresis (CAH = 55° - 45°), and due to the high wettability of the surface, droplets dimension was defined with a dimensionless parameter B/H. Under high crossflow condition (15 m/s) a sliding behaviour was observed. The channel features determined through image processing were used as boundary conditions for a 2D CFD two phase simulation employing the Volume of Fluid (VOF) model to keep track of the fluids interface. A droplet
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