Large Volumes Of Air Research Articles

Emergency physician ultrasound diagnosis of pneumoperitoneum in intraoperative patients with peritoneal insufflation.

To determine the accuracy of emergency physicians (EPs) in diagnosing pneumoperitoneum with POCUS, and if the volume of pneumoperitoneum affects accuracy. POCUS clips were obtained from patients undergoing intraperitoneal insufflation for an elective laparoscopic procedure. Video clips of the right upper quadrant and epigastric regions were obtained prior to insufflation and then after 500ml, 1000ml, and 1500ml of insufflation. These clips were randomized and reviewed by three blinded ultrasound-trained EPs. For each clip they determined whether pneumoperitoneum was present or not. EPs chose correctly 71% of the time. Overall sensitivity for detecting pneumoperitoneum was 66% with a specificity of 85%. Sensitivity for detecting small, medium, and large volumes of air was 53%, 70%, and 73% respectively. The AUC for pneumoperitoneum overall was 0.753. The AUC for detecting small, medium, and large volumes of air was 0.688, 0.773, and 0.789 respectively. There was substantial agreement between EPs with a kappa of 0.658. POCUS for pneumoperitoneum had moderate sensitivity, high specificity and moderate accuracy. The sensitivities increased with increasing volumes of air. This data suggests that POCUS has similar sensitivity to CXR for pneumoperitoneum.

System design of a novel open-air brayton cycle integrating direct air capture

The Direct Air Capture (DAC) technology is essential for achieving carbon neutrality, as it enables processes with net-negative CO2 emissions. However, its widespread commercialization faces significant challenges due to high energy requirements. Numerous attempts have been made to address this issue through thermal integration, yet the fundamental challenge of the high cost associated with extracting large volumes of low-concentration CO2 from ambient air remains unresolved. In this study, the integration of Open-Air Brayton Cycle (OABC) as a solution to enhance overall system utilization by simultaneously utilizing large volumes of ambient air is introduced. Various OABC coupled temperature swing adsorption based DAC system layouts are analyzed while considering different regeneration temperatures, and the results revealed the optimal configurations that significantly reduce energy cost per captured unit of CO2 with high purity and recovery. By combining an equilibrium short-cut model for temperature swing adsorption with process simulation methodologies, this research proposes the concept of “energy cost”—a metric that represents the amount of CO2 captured against the energy penalty incurred by integrating DAC with OABC systems. The findings demonstrate that combining DAC and OABC systems could yield high purity and recovery rates of CO2 through strategic thermal management and advanced adsorbent usage, offering a synergistic approach to carbon capture from an energy consumption perspective.

Feasibility and Effectivity of an Amine-Grafted Alumina Adsorbent for Direct Air Capture.

Direct air capture (DAC) has been identified as a necessary negative emission technology (NET) to solve global warming. DAC methods have been divided into two major types: solvent absorption and sorbent adsorption. Aqueous amine absorption is the major method in postcombustion carbon capture, not in DAC because contactors blow large volumes of air over the solvent, which results in high evaporation of solvents. Solid amine adsorption has been one of the primary methods of DAC due to its low volatility of amine. Therefore, the development of DAC adsorbents is the key to improve CO2 capture efficiency. Nowadays, the research on adsorbents mainly focuses on amine impregnation and grafting. The grafting adsorbents generally have better stability than impregnation adsorbents. Silica is the most common support material for amine-grafted adsorbents. Nonetheless, silica has some defects, such as poor hydrothermal stability, which limits its employment. Alumina is a promising support material with excellent hydrothermal stability, but studies on amine-grafted alumina are still scarce. Herein, a method of 3-[2-(2-aminoethylamino)ethylamino] propyltrimethoxysilane (TRI) grafting onto γ-alumina is presented. The results of this paper suggest that alumina is a potential support material for amine grafting. The CO2 adsorption capacity of the adsorbent is 0.39 mmol g-1 at 400 ppm and 25 °C. The amine-grafted alumina has excellent thermal stability than the amine-impregnation silica adsorbent. Besides, the adsorbent exhibits stable performance during cycles, with the working capacity maintained at 83% of that of the first cycle after 60 cycles. Water adsorption capacity and selectivity indicate that TRI-Al2O3 has good selectivity at high relative humidity. These findings make amine-grafted alumina a promising DAC adsorbent.

Experimental investigation of the influence of drainage condition on change in saturation of sheared sand

This paper investigates the validity of the interpretation of results from testing saturated axisymmetric triaxial compression (ATC) sand specimens utilizing 3D synchrotron micro-computed tomography (SMT) to probe localized events that are completely missed or misinterpreted when analyzing ATC measurements based on global standard measurements. Drained and undrained experiments were conducted at low and high back pressures (BPs) coupled with multiple in situ 3D-SMT to acquire high-resolution scans of the specimens at different axial strains. Specimens tested under low BP exhibited a large pore air volume change, which was not detected by the pump system that represents standard volume measurement. The increase in air volume caused a significant reduction in the degree of saturation leading to a possible transition from saturated to partially saturated constitutive behavior. Undrained experiments exhibited a significant volume change contrary to the assumption of negligible volumetric strain for saturated undrained experiments. Air bubbles within the shear band for drained and undrained low BP specimens showed opposite capillary pressure responses, increased for drained and decreased for undrained cases, due to the variation in the mechanism by which each of the two experiments predominantly counters the volume expansion within the shear band.

Research on the Effect of Deflection Secondary Air on Slagging in Coal Fired Boilers

Abstract In response to the slagging phenomenon in coal-fired boilers, the combustion characteristics of pulverized coal and the effect of deflected secondary air on slagging in a 350MW Corner-tangentially-fired boiler are numerically investigated by the commercial software. The research results indicate that when the deflection secondary air (CFS air) volume increases, the tangential diameter will significantly increase, and the degree of influence is higher than the angle, which has a significant impact on wall temperature and smoke wall brushing. Only adjusting the CFS wind angle or wind volume has a relatively small impact on particle wall brushing; When CFS wind is superimposed with large Angle and high air volume, the temperature and the degree of smoke brushing near the water wall will be significantly increased, and the risk of slag formation on the water wall will be magnified.

Research and design of low-noise cooling fan for fuel cell vehicle

Abstract The main noise source of fuel cell vehicles comes from the cooling vehicle, which has the characteristics of high voltage and large air volume. However, the large air volume makes the fan noise level significantly increase, reaching about 70dB. Even if the car adopts a variety of physical noise reduction methods, the noise level inside the car is still high, seriously affecting the passenger ride experience. In recent years, related research combined with bionic technology to improve the fan blade by designing a new shape structure, so that it has similar characteristics to some organisms to achieve the purpose of noise reduction. In this paper, ANSYS-CFX software is used to simulate the fan efficiency and noise level under different blade numbers, predict its performance, and optimize its structure.

Performance analysis of range hoods with different exhaust air volumes

This study investigated the effect of exhaust air volumes on the performance of range hoods at different angles in residential kitchens in removing grease pollutants, during the pollutant emission stage (whilst cooking) and the pollutant attenuation stage (after cooking). Experiments were conducted, and introduced indexes such as capture efficiency, exposure rate, attenuation rate, power and multi-indicator analysis were used to analyze the performance of the range hood with different exhaust air volumes and angles. The experimental results showed the capture efficiency was increased with an increase in exhaust air volume whilst cooking. Considering the energy consumption of the range hood and noise, the exhaust air volume of the range hood should be set at 600 m3/h to 800 m3/h. In the pollutant attenuation stage, the attenuation rate K of PM2.5 mass concentration was increased with the incremental increase in the exhaust air volume. When cooking was finished, grease pollutants remained in the kitchen. If the range hood continued to be turned on and a large exhaust air volume was set, the concentration of indoor grease pollutants could be quickly reduced to below the standard value. Our findings can provide a reference for the airflow regulation of residential kitchen range hoods.

Density scaling approximation for Monte-Carlo simulations of radioactive plumes

The release of radioactive gas into the atmosphere can diffuse into large volumes of air downwind from the point of release. The extent of radioactivity can cover thousands of cubic meters of air. For such large volumes, the weather models used to predict the down-wind distribution of the plume and the radiation transport models used to predict the radiation reaching ground-level from the plume can take tens of hours of computer time on multi-node institutional High-Performance Computing facilities.In this paper we focus on the radiation transport aspect of plume modeling. We describe a phenomenological method for approximating the amounts of radiation that reach ground level from large volumes of a static radioactive plume that can be calculated on a stand-alone personal computer in much shorter computation times than those usually needed for such large volume evaluations. We refer to this method as the Density Scaling Approximation (DSA). Its ability to approximate ground-level count rates of large plumes comes from using a small-plume volume with a scaled-up value of air density to simulate the same number of scatterings that occur during transport in larger plume volumes at normal air density.We demonstrate the DSA by using a 100 m-diameter air-filled hemispherical dome geometry with a uniform volumetric activity of 135Xe gas throughout the air-filled volume. The DSA for a larger dome diameter is obtained by evaluating the 100 m dome with an air density scaled up by the linear ratio of the larger diameter to the 100 m diameter. We find that this approximation works well for dome diameters up to 1200 m – the largest diameter studied and a size more than sufficient for accounting for all the radiation from 135Xe. Moreover, most of our DSA results can be calculated over 500 times faster than corresponding full-sized geometry with normal air density.To help evaluate the accuracy of the DSA and gain insight into how well it can reproduce different regions of the spectra, we use three, easily understood regions of interest to compare the DSA results to the full-sized geometry at normal air density results. These regions are the full-energy peak, the region of single-Compton scattering, and the region of multiple-Compton scattering. We show how the dominance of the Compton scattering mechanism determines this division and thus provides insight into how Compton scattering is manifested in spectra from photon scattering through air in general, and how well the DSA approximation works.

Reducing Energy Consumption and Greenhouse Gas Emissions of Industrial Drying Processes in Lithium-Ion Battery Cell Production: A Qualitative Technology Benchmark

As the world’s automotive battery cell production capacity expands, so too does the demand for sustainable production. Much of the industry’s efforts are aimed at reducing the high energy consumption in battery cell production. A key driver is electrode drying, which is currently performed in long ovens using large volumes of hot air. Several drying technologies from other industries could reduce energy consumption and greenhouse gas emissions if successfully applied to battery cell production. High process and quality requirements must be met when adapting these technologies for battery cell production. Evaluating the technologies against these requirements is difficult due to the technological novelty of this industry and the associated lack of data. Furthermore, the significant differences in drying technologies render a comparison even more challenging. One objective of this study was to evaluate drying technologies and identify those that could be best adapted to lithium-ion battery cell production. Near-infrared and laser drying were found to be the best in terms of energy efficiency, cost savings and other parameters. Another aim was to analyse, in more detail, the technological challenges and the advantages and disadvantages of the top-ranked drying technologies. Finally, the saving potential for greenhouse gas emissions of near-infrared and laser drying was calculated for a global production scenario of LIB cells in 2030. The saving potential in this scenario would amount to 2.63 million metric tonnes (Mt) CO2eq per year if near-infrared drying was applied in all global LIB cell production facilities within the mentioned scenario and 1.47 million Mt CO2eq per year for laser drying.

Exploring paperless working: A step towards low carbon footprint

Mass production of paper is one of the significant factors that are contributing to increase in carbon outrush in the global ecological system. The paper trade releases large volumes of air, water, and soil pollutants, which pony up to green house gasses. The rotted paper releases methane gas, which is many times more hazardous than carbon dioxide. Paperless business is a vital environmental business practice that is better for the upliftment of the current degrading environment. Global corporations are promoting paperless workplaces to move a step forward towards a sustainable ecological system and achieve the sustainable development goals of the United Nations. The research study after observation opined that although various challenges are being portrayed by employing digitalization of workplaces still working paperless is quite fruitful for the global ecological system. The digital innovations are the only alternatives available in the current times for the paper based job places. In this research study fairly was also studied the critical aspect of paperless workplace. On analyzing the dark data of the global corporeal world it was depicted that digitalization is also enhancing the carbon footprint. It is thus concluded in this research study that sensible and secure use of digital technology could only make paperless working successful.

Iatrogenic air embolism: pathoanatomy, thromboinflammation, endotheliopathy, and therapies.

Iatrogenic vascular air embolism is a relatively infrequent event but is associated with significant morbidity and mortality. These emboli can arise in many clinical settings such as neurosurgery, cardiac surgery, and liver transplantation, but more recently, endoscopy, hemodialysis, thoracentesis, tissue biopsy, angiography, and central and peripheral venous access and removal have overtaken surgery and trauma as significant causes of vascular air embolism. The true incidence may be greater since many of these air emboli are asymptomatic and frequently go undiagnosed or unreported. Due to the rarity of vascular air embolism and because of the many manifestations, diagnoses can be difficult and require immediate therapeutic intervention. An iatrogenic air embolism can result in both venous and arterial emboli whose anatomic locations dictate the clinical course. Most clinically significant iatrogenic air emboli are caused by arterial obstruction of small vessels because the pulmonary gas exchange filters the more frequent, smaller volume bubbles that gain access to the venous circulation. However, there is a subset of patients with venous air emboli caused by larger volumes of air who present with more protean manifestations. There have been significant gains in the understanding of the interactions of fluid dynamics, hemostasis, and inflammation caused by air emboli due to in vitro and in vivo studies on flow dynamics of bubbles in small vessels. Intensive research regarding the thromboinflammatory changes at the level of the endothelium has been described recently. The obstruction of vessels by air emboli causes immediate pathoanatomic and immunologic and thromboinflammatory responses at the level of the endothelium. In this review, we describe those immunologic and thromboinflammatory responses at the level of the endothelium as well as evaluate traditional and novel forms of therapy for this rare and often unrecognized clinical condition.

Cold season dose rate contributions from gamma, radon, thoron or progeny in legacy mines with high natural background radiation.

In areas with high natural background radiation, underground cavities tend to have high levels of airborne radionuclides. Within mines, occupancy may involve significant exposure to airborne radionuclides like radon (222Rn), thoron (220Rn) and progeny. The Fen carbonatite complex in Norway has legacy mines going through bedrock with significantly elevated levels of uranium (238U) and especially thorium (232Th), and significant levels of their progeny 222Rn and 220Rn. There are also significantly elevated levels of gamma radiation in these mines. These mines are naturally chimney ventilated and release large volumes of air to the outdoors giving a large local outdoor impact. We placed alpha track detectors at several localities within these mines to measure airborne radionuclides and measured gamma radiation of bedrock at each locality. The bedrock within the mines shows levels up to 1900Bqkg-1 for 238U, 12000Bqkg-1 for 232Th and gamma dose rates up to 11μSvh-1. Maximum levels of airborne radionuclides were 45000Bqm-3 for 220Rn and 6900Bqm-3 for 222Rn. In addition, we measured levels of thoron progeny (TnP). In order to estimate radiation dose contribution, TnP should be assessed rather than 220Rn, but deposition-based detectors may be biased by the airflow of mine-draft. We present dose rate contributions using UNSCEAR dose conversion factors, and correcting for airflow bias, finding a combined cold season dose rate within these mines of 17-24μSvh-1. Interestingly, fractional dose rate contributions vary from 0.02 to 0.6 for gamma, 0.33 to 0.95 for radon and 0.1 to 0.25 for TnP.

Computational Analysis of Tumor Treating Fields for Non-Small Cell Lung Cancer in Full Thoracic Models

Tumor Treating Fields (TTFields) are alternating electric fields at 150 to 200 kHz that exert their anticancer effect by destroying tumor cells when they undergo mitosis. TTFields are currently being tested in patients with non-small cell lung cancer with advanced disease (NCT02973789) and those with brain metastasis (NCT02831959). However, the distribution of these fields within the thoracic compartment remains poorly understood. Using positron emission tomography-computed tomography image data sets obtained from a series of 4 patients with poorly differentiated adenocarcinoma, the positron emission tomography-positive gross tumor volume (GTV), clinical target volume (CTV), and structures from the chest surface to the intrathoracic compartment were manually segmented, followed by 3-dimensional physics simulation and computational modeling using finite element analysis. Electric field-volume histograms, specific absorption rate-volume histograms, and current density-volume histograms were generated to produce plan quality metrics (95%, 50%, and 5% volumes) for quantitative comparisons between models. Unlike other organs in the body, the lungs have a large volume of air, which has a very low electric conductivity value. Our comprehensive and individualized models demonstrated heterogeneity in electric field penetration to the GTVs with differences upwards of 200% and yielded a diverse range of TTFields distributions. Target contact with the conductive pleura intensified TTFields at the GTV and CTV. Furthermore, in a sensitivity analysis, varying electric conductivity and mass density of the CTV altered TTFields coverage to both the CTV and GTV. Personalized modeling is important to accurately estimate target coverage at the tumor volumes and surrounding normal tissue structures in the thorax.

Experimental study on the thermal characteristics of a 3D thermosyphon heat sink

Phase change heat transfer has received extensive attention in the thermal management of electronic devices. Most studies of heat pipe or vapor chamber were limited to one- or two-dimensional heat transfer mode. Enhancing the phase change heat transfer to three-dimensional mode in heat sinks and exploring the thermal behavior of the heat sinks deserve a dedicated study. In this paper, a three-dimensional thermosyphon (3D-TS) heat sink combining the superiorities of the vapor chamber, thermosyphon and folded fins was experimentally investigated. The experimental reliability was validated and consolidated by the heat loss analysis, and an iteration method was proposed to estimate the saturation temperature to facilitate the in-depth analysis of the results. The coupling characteristics of the air forced convection and phase change heat transfer, and the effects of the heating power and air volume flow rate on the thermal resistance of 3D-TS were involved in the discussion. The main results indicate that the overall thermal resistance exhibits a negative correlation with the heating power and the air volume flow rate. The lowest thermal resistance of 0.14 K·W−1 was achieved with Qtotal = 300 W and 100 CFM air volume flow rate. High temperature on the folded fins indicates that the phase change heat transfer extends from the flat vapor chamber to the vertical thermosyphon tubes. It is also found that for a small heating power, a relatively large air volume flow rate is not able to further reduce the overall thermal resistance due to inadequate phase change intensity. The proposed heat sink is expected to solve the heat dissipation problems for densely packed electronic devices, which can produce favorable performance according to the input heating power and appropriate air volume flow rate.

Effects of Duct Height and Fire Location on Fire Phenomena of Enclosure with Two Horizontal Vents Installed on Ceiling

The effects of duct height (DH) and fire location (FL) in an enclosure on the mass flow rate and flow pattern of horizontal vent (HV) flow and temperature distribution in the enclosure were investigated through numerical simulations under the condition that two HVs were installed on the ceiling of the enclosure. To evaluate the effect of DH, DHs of HV1 were set to 0.19 m (HV1_DH0.19) and 0.05 m (HV1_DH0.05) under the condition that DH of HV2 was 0.05 m (HV2_DH0.05). The effect of FL was evaluated in three cases where the fire sources were located in the center of the floor (F LC), below HV1 (F L1), and below HV2 (F L2). With respect to the DH effect, the total mass flow rate of the vent flow was slightly higher and temperature was slightly lower in the case of HV1_DH0.19 than that in the case of HV1_DH0.05. However, considering the error bars, the effect of DH in this numerical simulation condition was considered to be insignificant. Furthermore, bidirectional flow patterns appeared in HV1 and HV2 in both DH conditions. Meanwhile, with respect to the FL effect, a bidirectional flow dominated by the mass flow rate of outflow occurred in the HV where the fire source was located, and a unidirectional inflow dominated by the mass flow rate of inflow occurred in the HV where the fire source was not located. The total mass flow rates of FL1 and FL2 conditions were similar, which were higher than those of FLC condition. The temperature was higher in FLC than those in FL1 and FL2. This was due to the small mass flow rate through the HV in the FLC. Meanwhile, an increasing trend of the temperature with the rising measurement height from the floor was observed at most of the temperature measurement points. However, when the fire source was located below HV1 and HV2, as the height from the floor increased, the temperature decreased and the overall temperature was low at the temperature measurement points below the vent where the fire source was not located. This trend was attributed to the occurrence of a strong unidirectional inflow wherein a large volume of low-temperature air flowed into the enclosure from the HV where the fire source was not located.

Development of a high-speed bioaerosol elimination system for treatment of indoor air

We developed a high-speed filterless airflow multistage photocatalytic elbow aerosol removal system for the treatment of bioaerosols such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Human-generated bioaerosols that diffuse into indoor spaces are 1–10 μm in size, and their selective and rapid treatment can reduce the risk of SARS-CoV-2 infection. A high-speed airflow is necessary to treat large volumes of indoor air over a short period. The proposed system can be used to eliminate viruses in aerosols by forcibly depositing aerosols in a high-speed airflow onto a photocatalyst placed inside the system through inertial force and turbulent diffusion. Because the main component of the deposited bioaerosol is water, it evaporates after colliding with the photocatalyst, and the nonvolatile virus remains on the photocatalytic channel wall. The residual virus on the photocatalytic channel wall is mineralized via photocatalytic oxidation with UVA-LED irradiation in the channel. When this system was operated in a 4.5 m3 aerosol chamber, over 99.8% aerosols in the size range of 1–10 μm were removed within 15 min. The system continued delivering such performance with the continuous introduction of aerosols. Because this system exhibits excellent aerosol removal ability at a flow velocity of 5 m/s or higher, it is more suitable than other reactive air purification systems for treating large-volume spaces.

Nature-inspired trapped air cushion surfaces for environmentally sustainable antibiofouling

Feathers of seabirds and waterfowl (for example the mallard duck (Anas platyrhynchos)) consist of hierarchical fibrillar structures encapsulated with hydrophobic preen oil. These characteristics afford waterproofing through the entrapment of air pockets, enabling swimming and diving for such bird species. This liquid repellency mechanism for bird feathers is mimicked by surface hydrophobisation of fibrous nonwoven polypropylene textiles to create large volumes of trapped air at the solid–liquid interface (plastron). Higher static water contact angle values correlate to a greater resistance towards water ingress (akin to the behaviour of mallard feathers). In order to extend the trapped gas layer lifetimes, the transportation of air from the water surface to a submerged air bubble by the diving bell spider (Argyroneta aquatica) for respiration is mimicked via short duration (< 1 s) solar-powered air bubble bursts once every 2 h. This combination of ornithological and arachnological inspired approaches yields stable trapped gas layers at the solid–liquid interface which are shown to inhibit biofouling in real-world outdoor wet environments.

Coherent infrasound generation using an air-propane burner

An invaluable tool in characterization of any receiver, propagation path, or detection system, is a source with known and repeatable signal characteristics. This talk will discuss development and evaluation of a coherent (non-explosive, periodic, with controlled duration) infrasound source with frequency capabilities in the sub-hertz to several hertz band. Design of a practical sound source within this band is a difficult engineering challenge. The simple source equation, which will govern any portable human-fabricated infrasound source due to the long wavelengths, shows this fundamental difficulty. As frequency decreases volume displacement must increase by the squared inverse factor of frequency in order to maintain an equal pressure amplitude at equal range. For this reason, the authors investigate utilizing the high energy density available in gas combustion to periodically displace large volumes of air within the open atmosphere. Prototype testing has verified the capability of generating continuous signals at a fundamental frequency of 0.25–1.5 Hz in the farfield—or ranges from the source where pressure and particle velocity are roughly in-phase. Harmonics of this fundamental are also generated throughout the 0.25–4.0 Hz band with reasonable signal-to-noise ratio. Development of the infrasound source prototype as well as experimental testing and results will be discussed.

SOPHISTICATED AIR HEAD: A UNIQUE PRESENTATION OF IATROGENIC AIR EMBOLISM IN SOFT TISSUE OF THE NECK AND CHEEK

SOPHISTICATED AIR HEAD: A UNIQUE PRESENTATION OF IATROGENIC AIR EMBOLISM IN SOFT TISSUE OF THE NECK AND CHEEK

Posttraumatic Tension Pneumocephalus Causing Atropine-Resistant Bradycardia

AbstractPneumocephalus is a serious complication following brain trauma. Tension pneumocephalus (TP) is entrapment of a large volume of air in the cranial vault causing mass effect on the brain parenchyma. It is the intracranial counterpart of tension pneumothorax and if neglected, can be life threatening. TP should be timely differentiated from benign pneumocephalus owing to its various nonspecific and lethal complications. Our patient is a 37-year-old male with a history of road traffic accident who presented to our hospital with headache and nasal discharge for the last two days. Computed tomography showed multiple skull fractures and extensive pneumocephalus. His preoperative heart rate was 38 beats per minute that was resistant to pharmacological interventions and required a temporary pacemaker for surgery. He underwent uneventful craniotomy for dura repair and was discharged home with no neurological deficit.