Vaporization Characteristics Research Articles

Volatolomics for Anticipated Diagnosis of Cancers with Chemoresistive Vapour Sensors: A Review

The anticipated diagnosis of cancers and other fatal diseases from the simple analysis of the volatiles emitted by the body (volatolome) is getting closer and closer from becoming reality. The promises of vapour sensor arrays are to provide a rapid, reliable, non-invasive and ready-to-use method for clinical applications by making an olfactive fingerprint characteristic of people’s health state, to increase their chance of early recovery. However, the different steps of this complex and ambitious process are still paved with difficulties needing innovative answers. The purpose of this review is to provide a statement of the blocs composing the diagnostic chain to identify the improvements still needed. Nanocomposite chemo-resistive transducers have unique prospects to enhance both the selectivity and sensitivity to volatile biomarkers. The variety of their formulations offers multiple possibilities to chemical functionalization and conductive architectures that should provide solutions to discriminations and stability issues. A focus will be made on the protocols for the collection of organic volatile compounds (VOC) from the body, the choice of vapour sensors assembled into an array (e-nose), in particular, chemo-resistive vapour sensors, their principle, fabrication and characteristics, and the way to extract pertinent features and analyse them with suitable algorithms that are able to find and produce a health diagnosis.

Establishment and Evaluation of Atmospheric Water Vapor Inversion Model Without Meteorological Parameters Based on Machine Learning.

Precipitable water vapor (PWV) is an important indicator to characterize the spatial and temporal variability of water vapor. A high spatial and temporal resolution of atmospheric precipitable water can be obtained using ground-based GNSS, but its inversion accuracy is usually limited by the weighted mean temperature, Tm. For this reason, based on the data of 17 ground-based GNSS stations and water vapor reanalysis products over 2 years in the Hong Kong region, a new model for water vapor inversion without the Tm parameter is established by deep learning in this paper, the research results showed that, compared with the PWV information calculated by the traditional model using Tm parameter, the accuracy of the PWV retrieved by the new model proposed in this paper is higher, and its accuracy index parameters BIAS, MAE, and RMSE are improved by 38% on average. At the same time, the PWV was inverted by radiosonde data in the study area as a reference to verify the water vapor inversion results of the new model, and it was found that the BIAS of the new model is only 0.8 mm, which has high accuracy. Further, compared with the LSTM model, the new model is more universal when the accuracy is comparable. In addition, in order to evaluate the spatial and temporal variation characteristics of the atmospheric water vapor retrieved by the new model, based on the rainstorm event caused by typhoon in Hong Kong of September 2023, the ERA5 GSMaP rainfall products and inverted PWV information were comprehensively used for analysis. The results show that the PWV increased sharply with the arrival of the typhoon and the occurrence of a rainstorm event. After the rain stopped, the PWV gradually decreased and tended to be stable. The spatial and temporal variation in the PWV have a strong correlation with the occurrence of extreme rainstorm events. This shows that the PWV inverted by the new model can respond well to extreme rainstorm events, which proves the feasibility and reliability of the new model and provides a reference method for meteorological monitoring and weather forecasting.

Evolution characteristics of ammonia and water vapor in the drying process of sewage sludge: Combined effect of drying temperature and cooling water

ABSTRACT The emission of hazardous and odorous gases from sewage sludge (SS) treatment is an issue of public concern. The evolution characteristics of ammonia and water vapor during the drying process of municipal SS were studied in this work. The removal tests of ammonia and water vapor were also carried out in the 15°C and 25°C cooling water. The results indicated that the drying process of SS can be categorized into three stages: raising rate stage, constant rate stage, and falling rate stage. The total drying time gradually reduced as drying temperature increased. The ammonia or water vapor emission concentration continuously increased with drying time, then remained constant for a period of time, and finally decreased when SS was completely dried. The cumulative yield of ammonia at a high drying temperature was greater than that at low temperature. The removal performance of ammonia/water vapor in the 15°C cooling water was superior to that in 25°C. Deep cooling method has a certain removal effect on the ammonia and water vapor emission, which is related to drying temperature and cooling water temperature. The obtained results are important references for SS managers to choose an appropriate removal technology to reduce the emissions of ammonia and water vapor from SS drying treatment.

Reconciliation of the vapor pressure temperature dependences of poorly studied substances. Part I: Individual compounds

Reconciliation of the vapor pressure temperature dependences of poorly studied substances. Part I: Individual compounds

Experimental Study on the Influences of the Fines Contents and Initial Moisture on the Water and Salt Migration of Coarse-Grained Saline Soil Subgrades

The construction of roads in saline soil areas usually involves using coarse-grained soil as roadbed fill material; studying the water–vapor–salt migration mechanism in coarse-grained saline soil subgrades is crucial for ensuring the stability of highway infrastructure. In order to clarify the influence of fines content and initial moisture on the water–salt migration and to clarify the water–vapor–salt migration patterns in coarse-grained saline soil, a model test of coarse-grained saline soil was conducted to study the response patterns of external water replenishment, final moisture content, final salt content, and liquid level height of coarse-grained saline soil. The results indicated that the water vapor migration amount only causes a change in the final moisture content, albeit not enough to cause salt redistribution. With increasing initial moisture content in coarse-grained saline soil, the migration characteristics of water vapor are weakened, and it imposes a significant inhibitory effect on liquid water migration at the same time. Increasing fines content in coarse-grained soil significantly inhibits water vapor migration, whereas liquid water migration is promoted. Water and salt accumulate in the liquid and vapor coupling migration mode at different heights. Based on the mechanisms of water vapor and salt transport characteristics, this study proposes a novel roadbed structure, which is vital for ensuring the long-term service performance of coarse-grained saline soil roadbeds in saline soil areas.

Water vapor and soot spatial characteristics retrieve of axisymmetric optically-thin laminar diffusion flame based on visible and near-infrared multi-spectral light field imaging

Water vapor and soot spatial characteristics retrieve of axisymmetric optically-thin laminar diffusion flame based on visible and near-infrared multi-spectral light field imaging

Onboard measurements of organic vapor emissions from river vessels under various operational conditions

The emission factors and characteristics of pollutants from river vessels are critical for understanding the environmental impact of ship emissions, particularly in inland waterways. However, research gaps remain regarding emissions of volatile organic compounds (VOCs) and intermediate-volatility organic compounds (IVOCs) from river vessels. In this study, we collected and analyzed organic vapor emissions, including non-methane hydrocarbon (NMHCs), oxygenated volatile organic compounds (OVOCs) and IVOCs, from three river vessels under different operating conditions. The results show that the average emission factors of NMHCs, and IVOCs from river vessels are significantly higher than those from ocean-going vessels. Inland waterways' proximity to residential areas increases the risk of pollutant transport to urban environments, heightening the importance of managing river vessel emissions. Notably, older auxiliary engines displayed higher organic vapor emissions compared to main engines, underscoring the need for better control measures for aging engines. By analyzing the emission characteristics of organic vapors from river vessels, it was found that, unlike other pollution sources where C12 n-alkanes are the major contributors of IVOCs, the contributions of C12-C15 n-alkanes in river vessel exhaust are similar, with C14 n-alkane having the highest contribution. OVOCs constituted more than 50% to ozone formation potentials of organic vapors, while IVOCs were responsible for over 90% of the secondary organic aerosol (SOA) formation. Given these findings, targeted efforts to reduce OVOCs and IVOCs emissions from river vessels should prioritized to mitigate their environmental impact.

Enhanced VOCs adsorption with UIO-66–porous carbon nanohybrid from mesquite grain: A combined experimental and computational study

In this study, adsorption of volatile organic compounds (VOCs) (here just gasoline vapor) by activated carbon- modified UIO-66 was investigated. First, activated carbon prepared from mesquite grain (ACPMG) and then UIO/ACPMG nanohybrid was synthesized by the solvothermal method. In following, the effect of main key parameters which effect on the surface and adsorption capacity such as the ratio of ACPMG to UIO-66 was studied. Physiochemical changes of as- synthesized samples were investigated by TGA, HR-TEM, PSD, SEM, EDX/MAP, BET, FT-IR, XRD, and XPS. It was found the UIO/ACPMG20% nanohybrid had the highest adsorption capacity (391.304 mg/g) for VOCs compared with the other samples, while the adsorption capacity of UIO-66, UIO/ACPMG10% nanohybrid, and UIO/ACPMG30% nanohybrid was 298.871, 309.523, and 320 mg/g respectively. UIO/ACPMG20% nanohybrid desorbed 285.71 mg/g of the adsorbed gasoline, which is an excellent result in desorption. So, the sample of UIO/ACPMG20% nanohybrid was selected as the optimum nano-adsorbent. In other hand, all the nano-adsorbent showed a rapid kinetic behavior for gasoline vapor adsorption and the maximum time for reaching a high adsorption capacity approximately was obtained in 20 min. Density functional theory calculations also performed to understand the adsorption characteristics of gasoline vapor on activated carbon-modified UIO-66.

Investigation on metal vapor characteristics and keyhole/melt pool dynamics in high-power laser welding with side gas flow

High-power laser welding processes involve intense interactions between the laser beam and the base material, resulting in severe welding defects such as humping, spattering, and undercutting. Utilizing side gas flow may provide an effective approach for minimizing these defects. However, the effects of side gas flow on the dynamic behavior and weld formation necessitate further investigation. In this study, an innovative analysis of metal vapor characteristics and keyhole/melt pool dynamics in high-power laser welding with side gas flow is presented, combining experimental and simulation results. A three-dimensional transient fluid flow model was developed, uniquely integrating an adaptive heat source, evaporation-condensation processes, and metal vapor energy attenuation to provide a novel perspective on the effects of side gas flow in high-power laser welding. The results display that side gas flow could suppress plasma, increase thermal input to the melt pool, and intensify the flow of liquid metal toward the pool bottom during high power laser welding, thereby enhancing weld seam penetration. The numerical results indicate that variations in flow rate significantly impact metal vapor morphology, with higher flow rates reducing both the average area and height of the metal vapor and effectively suppressing the size of metal vapor/plasma. When the side gas flow rate is 20 l/min, with the gas flow impact point located at the keyhole opening and the nozzle height set to 3 mm, the side gas flow significantly enhances the depth-to-width ratio of the weld seam in 316L stainless steel laser welding. This work can provide guidance for suppression of weld defects in high-power laser welding of medium-thick steel components, which has important theoretical significance and application value.

The Heat Transfer Characteristics of Vapor Condensation in a Plate Heat Exchanger

Abstract The model of a single flow channel of a plate heat exchanger (PHE) has been established, and the condensation characteristics of vapor with different saturation temperatures and vapor superheating levels have been investigated. The results show that with a higher vapor saturation temperature, the average surface heat transfer coefficient (HTC) increases. The HTC of saturated steam at a saturation temperature of 348.15 K is about 104.1% higher than that at a saturation temperature of 323.15 K. The influence of vapor superheating is weaker compared to that of the saturation temperature. With the increase of vapor superheat, the surface average HTC first increased and then decreased. The HTC of superheated vapor with a vapor superheating of 10 °C is about 0.72% higher than that of saturated vapor. In industrial applications, it is appropriate to control the vapor inlet superheating to be between 5-10°C.

Visualization of Injected Fuel Vaporization Using Background-Oriented Schlieren Method

In this experimental study, ethanol, an eco-friendly fuel used to reduce harmful exhaust emissions from internal combustion engines, was blended with gasoline. To optimize the combustion and the shape of the combustion chamber, the spray development and spray behavior of ethanol and gasoline were visualized and compared. Droplets of injected fuel were visualized using a high-speed camera. Because it is difficult to experimentally observe fuel vaporization using only high-speed cameras, the vaporization characteristics of the spray were compared and analyzed by using the background-oriented schlieren (BOS) method with density variation and image displacement in the spray flow field to visualize the vaporized fuel. The experimental results indicate that the fuel vaporization phenomenon could be observed during the spray development and that more fuel vaporization occurred at higher ambient temperatures and lower ambient pressures. Additionally, the dependence of the differences in the vaporization characteristics of the fuel and the wall-wetting phenomenon caused by the vaporized fuel was analyzed.

Influence of Water Concentration on the Water/Vapor/ Oil Separation Process in a Vacuum Oil Filter: Modelling and Simulation

The vacuum oil filter (VOF) is widely applied in the oil-water emulsion demulsification separation due to the phase separation by using vacuum evaporation; however, the micro-dynamic characteristics of oil, water and vapor three phases and the influencing factors of separation efficiency are rarely studied. Therefore, the fluid flow and phase separation characteristics of water-in-oil emulsions were numerically analysed by ANSYS software. The demulsification conditions of water/oil emulsion were simulated by using the two-fluid model and the water evaporation model, and the turbulence effect was considered by using the Reynolds stress model. The results show that the established model could provide a convenient way to study the effects of the different water concentrations in oil; the turbulence intensity in VOF increases with the increase of water concentration in oil; The separation efficiency has been influenced by the inlet water concentration reaching values between 20.65-22.62% in the center axis, while 33.18-42.24% in the plate column; the vapor concentration ranged from 0 - 23.64% in the center axis, while 0 - 41.02% in the plate column. The relative volume fraction of water concentration decay tending with the water concentration increases, and the water concentration has a great influence on the separation efficiency.

Theoretical analysis of the initial nucleation characteristics of trace water vapor frosting on a cryogenic surface

Theoretical analysis of the initial nucleation characteristics of trace water vapor frosting on a cryogenic surface

Numerical Study on the Influence of Various Design Variables on the Behavior Characteristics of Oil and Gas in Internal Floating Roof Tanks

With the development of the petrochemical industry, the number of storage tanks has continuously increased, exacerbating the issue of oil evaporation losses. Therefore, it is urgent to find efficient and economical measures to reduce oil evaporation losses. This paper establishes a diffusion model for internal floating roof tanks (IFRTs) and uses numerical simulation methods to study the mass fraction distribution, pressure distribution, and the variation patterns of oil vapor inside the tanks at different floating roof heights. The results show that the closer to the top of the tank, the lower the oil vapor mass fraction, and the mass fraction distribution is almost symmetrical. As the floating roof height decreases, the vapor mass fraction in the mixed gas region inside the tank gradually decreases, showing a distribution below the lower explosive limit (LEL), indicating improved safety. Furthermore, the study found that in the benchmark model, the behavior characteristics of gasoline vapor are reflected in the changes in mass fraction, velocity, and pressure distribution, where the oil vapor concentration in the upper part is lower but evenly distributed. By comparing the behavior characteristics of oil vapor inside the tank at different floating roof heights, it was found that the floating roof height significantly affects the diffusion and accumulation of oil vapor. The presence of vents effectively reduces the accumulation of oil vapor concentration, improving the stability and safety inside the tank. For different floating roof height scenarios (such as CASE 1, CASE 2, and CASE 4), the oil vapor behavior characteristics are similar. The study results provide important theoretical support for the future development of oil vapor recovery technologies and the design of enclosed energy-saving recovery devices inside tanks, indicating that optimizing the floating roof height and vent system design can significantly reduce oil evaporation losses.

Investigation on saturated vapor and two-phase refrigerant injection in the rotary compressor for the extreme hot and cold conditions

Investigation on saturated vapor and two-phase refrigerant injection in the rotary compressor for the extreme hot and cold conditions

Vaporization thermodynamics of normal alkyl azides

Vaporization thermodynamics of normal alkyl azides

Modelling of the conductor vaporization process for single-turn coil

Single-turn coil (STC) is a destructive pulsed magnet aiming at 100–300 T ultra high magnetic field. A conductor vaporization model is proposed for STCs. Using this model, the vaporization characteristics at different inner diameters and discharge currents are investigated. The results show that vaporization always starts from the inner surface of the conductor, but only from the interior of the conductor at higher current and smaller inner diameter. Moreover, the vaporization causes the electrical conductivity to decrease, leading the area with the highest current density to advance to the interior of the conductor. By comparison, the vaporization start time decreases as the current increases and the inner diameter decreases, and the vaporization start time at different diameters tends to coincide as current increases. The model in this study is validated by checking the consistency of the magnetic flux density at the central axis of STCs of the simulation results and the experimental data.

Rapid and simultaneous detection of cadmium and mercury in foods based on solid sampling integrated electrothermal vaporization technique

This work presents an innovative solid sampling (SS) integrated electrothermal vaporization (ETV) approach for simultaneous determination of Cd and Hg based on differentiated elemental vaporization and transportation behavior characteristics. A miniature N2/H2 generator, only consuming electricity and H2O, was utilized to yield reducing atmosphere for Cd vaporization; MgO filler was modified to absorb matrix interferent and keep Hg and Cd transportation via 1st catalytic pyrolysis furnace (CPF); and a gearing was employed to move 2nd CPF to receive and trap (amalgamation) the vaporized Hg from ETV and then thermo-release them for simultaneous detection. Under optimized conditions, the limits of detection of Cd and Hg reached 0.02-0.04ng/g using 0.4g sample size. The linearities (R2) exceeded 0.998 and recoveries were 85.0-111.9%, indicating favorable analysis precision and accuracy within ∼3min without sample digestion process. The proposed HgCd analyzer is suitable for rapid monitoring food with simplicity, green and safety.

Performance of Motorcycle Fueled with Pertalite‒LDPE Pyrolytic Oil Blendings

Plastic use has expanded substantially, and its waste is primarily disposed of in landfills, which further harm ecosystems owing to inadequate waste management. Pyrolysis, which converts plastic waste into liquid fuel, is one of the potential chemical recycling alternatives for plastic. The purpose of this study is to determine the viability of using pyrolytic oil from an LDPE grocery bag as an alternative fuel for a four-stroke spark ignition motorcycle engine. The LDPE grocery bag was pyrolyzed at 500 oC at a heating rate of 3 oC/min, and the condensed pyrolytic vapor's characteristics were determined. Torque, power, and fuel consumption were investigated using a four-stroke spark ignition motorbike powered by pertalite‒LDPE pyrolytic oil blends. The results reveal that the properties of LDPE pyrolytic oil and pertalite were considerably different; hence, when the blending fuel was applied to the motorcycle, the engine torque and power decreased at low engine speed (2000‒3500 rpm), about equal at medium speed (3500‒5500 rpm), and increased at high engine speed (5500‒8500 rpm). Furthermore, the greater blending fuel greatly reduced fuel usage due to the high viscosity of the LDPE pyrolytic oil.

Aberrant variations in land, oceanic, and atmospheric parameters precedent to earthquakes

The study of multi-sensor parameters before eleven earthquake (M ≥ 6.0) is reported in the current study. These earthquakes are: (1) Chile (28⁰44′ S, 71⁰28′ W) on 04 July 2021 (M = 6.0), (2) Panama (7⁰23′ N, 82⁰46′ W) on 21 July 2021 (M = 6.7) (3) Philippines (13⁰42′ N, 120⁰43′ E) on 23 July 2021 (M = 6.7) (4) Russia (48⁰51′ N, 154⁰54′ E) on 24 August 2021 (M = 6.0), (5) Taiwan (24⁰30′ N, 121⁰49′ E) on 24 October 2021 (M = 6.2), (6) Nicaragua (11⁰13′ N, 86⁰31′ W) on 09 November 2021 (M = 6.3), (7) Guatemala (14⁰08′ N, 91⁰23′ W) on 16 February 2022 (M = 6.2), (8) Philippines (14⁰05′ N, 119⁰22′ E) on 13 March 2022 (M = 6.4), (9) Japan (37⁰42′ N, 141⁰34′ E) on 16 March 2022 (M = 7.3), (10) Taiwan (23⁰23′ N, 121⁰36′ E) on 22 March 2022 (M = 6.7), (11) Philippines (19⁰01′ N, 121⁰21′ E) on 30 June 2022 (M = 6.0). We examined the SLHF, SST, CLW, and Water Vapor characteristics before the earthquakes to look for a precursory indication. The seasonal plot of every location for each parameter have plotted in the present paper (Fig. 2(a-d) to 12(a-d)). The SLHF, SST, CLW, and Water Vapor data show unusual behaviour in earthquakes between June 2021 to June 2022. The important aim of this study was to investigate and show that SLHF, SST, CLW, and water vapor could change during, before, or after earthquakes that occurred near or beneath an ocean. Our study could help us understand how the land, ocean, and atmosphere respond to earthquake activity.