Thin Liquid Layer Research Articles

Siphon-based scalable and salt-resistant multistage thermal desalination system

Recent advances in thermal localization-based passive solar desalination provide a great opportunity for the economical generation of freshwater, particularly in regions with insufficient energy and water infrastructure. Yet, the capillary-assisted passive desalination systems with a high-water productivity flux (measured in Lm−2 h−1) suffer from the issue of performance degradation due to salt accumulation and the inability to be scaled up. In this work, we propose siphon-based supply of saline water over the evaporator that enables scale up of the desalination system to a size significantly higher than the capillary rise height of the hydrophilic evaporator while preventing salt accumulation on the evaporator. The composite siphon comprises insulating fabric wick and a metallic grooved surface for localizing heat to evaporate a thin layer of saline liquid over the evaporator. We perform heat and mass transfer analysis to show that the thermal-to-vapor efficiency depends on the inlet mass flow rate and air gap between the evaporator and the condenser. We propose a methodology to passively control the mass flow rate to maximize the thermal to vapor efficiency at different input heat flux and initial concentration of the brine. A grooved condenser avoids mixing of brine and the freshwater, even at air gaps as low as 2 mm. A siphon-assisted 10-stage desalination system with a footprint area 15 cm × 15 cm and an air gap of 2 mm is shown to have a high water productivity flux of ~5.73 Lm−2 h−1 from 3.5 wt% saline water at an applied heat flux 1000 W/m2, which increases to a record high distillate flux of ~6.23 Lm−2 h−1 and thermal to water collection efficiency of ~423 % for a 15-stage system. The ability of the desalination system to maintain a high-water productivity flux even when the evaporator area is increased by 4 times demonstrates its scalability to achieve higher desalinated water productivity rate.

Spreading of rotating liquid annular ring with hysteresis effects

The spreading of a liquid, subjected to centrifugal forces or an air jet, leads to a lowering of the liquid height at the center. If the system is partially wetting, experiments show a break up of the liquid and the appearance of a dry patch at the center. In this article, the spreading of a liquid droplet or a liquid film, featuring a dry patch at the center, is investigated. Via a generalized Tanner’s law, we allow for a contact-angle hysteresis in partially wetting systems. By means of the lubrication approximation, an analytical quasi-steady solution can be derived in the limit of small capillary numbers. We find a power-law regime for the spreading, in which at least one of the contact lines follows a power law in time, almost independent of both static contact angles. The influence of the static contact angles remains restricted to the beginning of the spreading and to transition periods. Four different types of spreading can be identified, namely spreading (i) with a very thin central liquid layer, (ii) as annular ring with central dry patch, (iii) into a static equilibrium, and (iv) with closing of the central dry patch. In a flow map, these types of spreading are mapped as function of both static contact angles. Moreover, the dependency from gravitational and centrifugal forces is investigated and included in the flow map. For a perfectly wetting system, a disjoining-pressure correction in combination with Tanner’s law prohibits negative liquid heights at the center. Hereby, the magnitudes of the Hamaker constants have a negligible influence and arbitrary-small values can be used, since the dynamics of the contact line remains controlled by Tanner’s law.

Dynamic phase change materials with extended surfaces

Phase change materials (PCMs) present opportunities for efficient thermal management due to their high latent heat of melting. However, a fundamental challenge for PCM cooling is the presence of a growing liquid layer of relatively low thermal conductivity melted PCM that limits heat transfer. Dynamic phase change material (dynPCM) uses an applied pressure to pump away the melt layer and achieve a thin liquid layer, ensuring high heat transfer for extended periods. This paper investigates heat transfer during dynPCM cooling when the heated surface has extended features made from high thermal conductivity copper (Cu). Using experiments and finite element simulations, we investigate the heat transfer performance of dynPCM paraffin wax on finned Cu surfaces. A total of 102 transient temperature measurements characterize the performance of dynPCM with extended surfaces and compare the performance with other cooling methods including hybrid PCM and air cooling. The study examines the effects of fin geometry, applied power (20–65 W), and pressure (0.97–12.5 kPa). For dynPCM on a finned surface and a heating power of 65 W, the thermal conductance is 0.45 W/cm2-K, compared to 0.22 W/cm2-K for dynPCM on a flat surface and 0.10 W/cm2-K for hybrid PCM. The heat transfer is highest at the fin tips where the melt layer is thinnest, providing valuable design guidelines for future high performance dynPCM cooling technologies.

Numerical study of cavitation shock wave emission in the thin liquid layer by power ultrasonic vibratory machining

In the field of power ultrasonic vibration processing, the thin liquid layer nestled between the tool head and the material serves as a hotbed for cavitation shock wave emissions that significantly affect the material's surface. The precise manipulation of these emissions presents a formidable challenge, stemming from a historical deficit in the quantitative analysis of both the ultrasonic enhancement effect and the shock wave intensity within this niche environment. Our study addresses this gap by innovatively modifying the Gilmore-Akulichev equation, laying the groundwork for a sophisticated bubble dynamics model and a pioneering shock wave propagation model tailored to the thin liquid layer domain. Firstly, our study investigated the ultrasound enhancement effect under various parameters of thin liquid layers, revealing an amplification of ultrasound pressure in the thin liquid layer area by up to 7.47 times. The mathematical model was solved using the sixth-order Runge–Kutta method to examine shock wave velocity and pressure under different conditions. our study identified that geometric parameters of the tool head, thin liquid layer thickness, ultrasonic frequency, and initial bubble radius all significantly influenced shock wave emission. At an ultrasonic frequency of 60 kHz, the shock wave pressure at the measurement point exhibited a brief decrease from 182.6 to 179.5 MPa during an increase. Furthermore, rapid attenuation of the shock wave was found within the range of R0-3R0 from the bubble wall. This research model aims to enhance power ultrasonic vibration processing technology, and provide theoretical support for applications in related fields.

Simultaneous close-contact melting on two asymmetric surfaces: Demonstration, modeling and application to thermal storage

The present study deals with melting in a geometry suitable for Latent-Heat Thermal Energy Storage (LHTES) systems, which are of importance for future industrial installations utilizing solar energy or waste heat. The intrinsically high thermal resistance of phase-change materials (PCM) can be remedied by taking advantage of close contact melting (CCM), where the solid phase is separated from a hot surface by only a thin liquid layer. The basic CCM takes place on a horizontal flat surface, but during the last decade its application in various finned LHTES units has been demonstrated experimentally and analyzed numerically.Specifically, the configuration studied in the present work is relevant to a horizontal double-pipe concentric storage unit with a longitudinally finned inner tube. While this rather simple geometry has been extensively studied in the past, the present work is completely novel in its demonstration and analysis of simultaneous close-contact melting on two generally asymmetric surfaces created by the longitudinal fins. A unique experimental apparatus is introduced, based on the so-called 'Mercedes' configuration of the fins. It is designed transparent, allowing for real-time observation of melting sequences. Close-contact melting is achieved by supplying heat to the outer shell of the unit: the solid phase is detached from the shell and moves, by translation and rotation, in the liquid phase. The results from these experiments demonstrate the feasibility of CCM on two asymmetric walls within this system, hinting at the potential for optimizing the melting rate by utilizing a larger portion of the extended surface for CCM.A key component of this study is the development of a reliable numerical approach, which goes beyond the limitations of widely-applied enthalpy-porosity method and combines the general enthalpy formulation, convective heat transfer and general rigid body motion that includes rotation. Therefore, a new numerical model has been devised, using an in-house code realized in MATLAB. A full set of the governing conservation equations is solved using a finite-difference framework, integrated with advanced numerical methods for the fluid-solid interaction and an enthalpy formulation for the phase change process. The model is validated carefully, and then numerical studies are conducted to elucidate the melting process.The present paper presents a further proof of the special role that close-contact melting (CCM) can play in properly designed thermal energy storage units and finned systems in general. It is demonstrated that the fins, when properly designed and oriented, can induce CCM in their vicinity, contributing to a very significant increase in the melting rate, which reflects charging of the unit.

Experimental and analytical investigation of intensive cooling of local distributed heat sources by means of forced flow of liquid

In this work a two-phase forced flow in channels of small geometric dimensions is analyzed. The Navier-Stokes equation was used to create a theoretical model describing the phenomenon of a evaporation of a flowing vapor and the Maxwell equation was used to describe the flow of a thin liquid layer. Both equations are coupled and overall create an original theoretical model describing the phenomenon of the evaporation of a liquid layer. This model of a liquid forced convection cooling the flat element with distributed internal heat sources is theoretically and experimentally analyzed. A flow of the cooling and evaporating liquid is forced by a suction of the vacuum pump. The cooling process is investigated theoretically for two specific cases with both, a constant and a cyclic heat emission. The impact of the liquid layer thickness on the cooling intensity is analyzed for both cases.

Effect of shape and thermal conductivity of microstructured capillary-porous coatings on heat transfer during evaporation and boiling in thin horizontal liquid layers

Investigation results on heat transfer during evaporation and boiling in thin horizontal liquid layers on 2D modulated capillary-porous coatings with a sinusoidal profile in a wide range of relative pressures and layer heights are presented in this paper. Coatings were made on a 3D laser printer using the technology of additive selective laser sintering (SLS). One coating was made of bronze with a modulation wavelength equal to the Laplace constant of the working fluid and two coatings were made of stainless steel and bronze with a doubled wavelength. The experimental data obtained on the coatings were compared with each other and with the values obtained by evaporation and boiling of n-dodecane on a smooth surface under the same conditions. It is shown that in the region of low relative pressures in liquid layers with a height less than the Laplace constant, heat transfer intensification achieved on a sample made of a material with low thermal conductivity (stainless steel) was five times higher as compared to a smooth surface. In the range of relative pressures, when nucleate boiling was observed in the layers, the temperature difference reached on the bronze coatings was approximately 3–4 times less than on a smooth surface. The temperature difference for the stainless steel coating changed little with an increase in the heat flux. In pre-crisis conditions, the temperature difference during boiling on the stainless steel coating was less than on the bronze coatings in the entire range of relative pressures and layer heights. The highest critical heat fluxes were obtained on a bronze coating with a modulation wavelength equal to the Laplace constant.

Stagnant liquid layer as “Microreaction System” in submerged plasma Micro-Jet for formation of carbon quantum dots

This study aims to intensify reactivity via bespoke transient hydrodynamics in a plasma-activated three-phase catalyst system. Likewise, three-phase plasma systems in literature are not well designed, understood and commercially available. The synthesised N-doped carbon quantum dots, with application as fertilisers and wastewater treatment was evaluated as a model reaction. A plasma microjet was produced using a commercial plasma system, creating an almost flat, large interface covering a thin stagnant liquid layer with a catalyst bed underneath. In this hydrodynamic regime, plasma can penetrate the catalyst bed via the stagnant thin liquid film and polarise the plasma-liquid interface. The new process regime’s effectiveness is proven by the enhanced reaction rate achieved by raising liquid diffusivity toward the catalyst bed through solvent viscosity reduction. Results indicate that the reaction rate depends on the small surface area interacted with the plasma jet amid an excess of excited species, not the total gas–liquid interface area. The plasma process competes energetically with the best dielectric barrier discharge processes and uses less energy than microfluidic processing in chemical microreactors. High momentum transfer from the plasma jet to the liquid partly evaporates non-water additives, impacting process design and requiring reduction.

Division of Bénard-Marangoni cells in bottom heated thin rectangular liquid layers under high supercritical number

Though the time-dependent behavior of Bénard-Marangoni (BM) cells has been widely investigated in the past decades, most are concerned with the transformation of geometrical shape whereas few consider its division. Unlike the original incipience of the classical BM cell which comes from a static liquid layer with uniform surface temperature, the cell division occurs in a layer occupied by BM cells. The behavior of cell division is more complex than its original incipience, which is not yet understood clearly. The reason and critical conditions of the division are also unclear. The present work is aimed at these issues and a series of experiments are performed in bottom heated thin layers of silicone oil in rectangular pools. The results demonstrate that the cell division needs three conditions, i.e., an enough high supercritical number ε (= (Mav − Mac)/Mac), an enough high ratio k of local horizontal Marangoni number to local vertical Marangoni number of the cell, and five or more edges of the cell. Under enough high ε, a new cell is generated at a corner of the original cell where k is the largest among the cell corners. The percent of cell division increases with increases of ε and Pr. With increasing ε, the previous generated pentagonal cell further divides and the original cell eventually divides into three or even four cells. The threshold of the average ratio of the maximum local horizontal Marangoni number to the maximum local vertical Marangoni number for incipience of cell division is determined. The mechanisms of cell divisions are clarified and the flow field during division is provided by experiment and numerical simulation. This work helps for understanding the behavior of BM instability after generation.

Numerical Simulation of Convective Flows in a Thin Liquid Layer at Large Reynolds Numbers

Numerical Simulation of Convective Flows in a Thin Liquid Layer at Large Reynolds Numbers

Dynamics of a cavitation bubble confined in a thin liquid layer at null Kelvin impulse

In this work, we experimentally and numerically investigate cavitation bubble dynamics in a thin liquid layer surrounded by gas. We focus on configurations featuring strongly confined bubbles at dimensionless bubble-free surface stand-off distances D* below unity. Additionally, we impose the condition of null Kelvin impulse, subjecting a bubble to the oppositely equal influence of two opposing free surfaces, resulting in the formation of two convergent water jets. We observe a diverse spectrum of jetting phenomena, including broad jets, mushroom-capped jets, and cylindrical jets. These jets become progressively thinner and faster with lower D* values, reaching radii as small as 3% of the maximal bubble radius and speeds up to 150 m/s. Numerical results reveal a linear relationship between the jet impact velocity and the local curvature at the bubble region proximal to the free surface. This suggests that the magnitude of bubble deformation during its growth phase is the primary factor influencing the observed fivefold increase in the jet impact velocity in the parameter space considered. Our findings show that bubble collapse intensity is progressively dampened with increased confinement of its environment. As D* decreases beyond a critical value, the liquid layer separating the bubble and ambient air thins, leading to the onset of interfacial shape instabilities, its breakdown, and bubble atomization. Furthermore, we compare bubbles at zero Kelvin impulse to corresponding anisotropic scenarios with a single free surface, revealing that the dynamics of axial jets until the time of impact is primarily influenced by the proximal free surface. The impact of convergent axial jets at null Kelvin impulse results in local pressure transients up to 100 MPa and triggers the formation of a fast and thin annular outflow in the form of a liquid sheet, affected by the Rayleigh–Plateau and flapping shape instability.

Thin-film flow between a rotating sphere and a nearly vertical moving plate

When a sphere rotates near a rigid boundary coated with a thin layer of viscous liquid, ‘tracks’ are generated both behind and over the sphere. This paper describes a theory for the simplest one-track configuration which can occur under particular experimental conditions. The theoretical predictions are in good agreement with experimental observations.

Dispersion of waves propagating in the ice-covered Arctic Ocean

The Arctic Ocean was modeled as an ice–seawater–sediment system, where the ice cover and seawater were assumed to be inhomogeneous solid and liquid, respectively, while the sediment was assumed to be homogeneous liquid. Transfer matrixes relating the displacements and stresses at the lower surface and those at the upper surface for a thin solid layer, and a thin liquid layer were derived. Furthermore, a dispersion equation for waves propagating in the ice-covered Arctic Ocean was derived using the transfer matrix technique. The phase- and group-velocity dispersion curves were obtained by solving the dispersion equation numerically. The results show that the dispersion curves for the Arctic Ocean with ice cover are much more complex than those without ice cover. Except for the new mode, the phase-velocity curve for the n-th (n > 2) mode exhibited a slight distortion, which caused a sharp peak in the group-velocity curve. These peak values, which depend on the order of the mode, may be significantly higher than the speed of sound in seawater. The variation of the ice cover thickness had significant influence on the dispersion curves of the first and second modes. Moreover, the influence of the seawater depth on the dispersion curves were investigated.

Effects of Diffusion Thermo and Thermal Diffusion on an Unsteady MHD Dissipative Squeezing Flow of Casson Fluid Over Horizontal Channel in the Presence of Radiation and Chemical Reaction

This study analyses the impacts of Diffusion thermo and thermal diffusion on the magneto hydrodynamic (MHD) squeezing Casson fluid flow through a porous medium under the slip condition with viscous dissipation the presence of chemical reaction and thermal radiation. The flow is produced when two plates are compressed together in close proximity to one another. Using similarity variables may successfully convert partial differential equations (PDEs) to ordinary differential equations (ODEs). The shooting technique was used to perform the numerical analysis, which entailed solving the competent governing equations with dominating parameters for a thin liquid layer. This was done to determine the results of the study. It is essential to evaluate the numerical results in light of previously conducted research to validate the current answers. According to the results, an increase in the distance between the two plates leads to a rise in the velocity and the wall shear stress. The velocity diminishes due to an increase in the Hartmann and Casson parameters, whereas the reverse behaviour has been observed in the case of temperature and concentration. The opposite behaviour has been observed in temperature with increasing Diffusion thermo and thermal diffusion parameters.

The Concept of Using 2D Self-Assembly of Magnetic Nanoparticles for Bioassays

It can be observed that magnetic iron-oxide nanoparticles are increasingly used in bioassay methods. This is due to their stability in aqueous solutions, ease of functionalization, biocompatibility and very low toxicity. Here, we show that the recent discovery of the ability of magnetic nanoparticles to self-assemble into 2D structures of ordered chains may be exploited for bioassays. This would open up the possibility of controlled immobilization of proteins, enzymes, DNA or RNA and other molecular systems on spatially ordered nanostructures. In this work, fluorescein was used as an example. Also shown is the possibility of using Raman spectroscopy to analyze material accumulated on such structures. The observed formation of regularly spaced chains of magnetic nanoparticles takes place during the drying process of a thin layer of magnetic liquid placed on an appropriately prepared low-density polyethylene (LDPE) film.

FEATURES OF THE FILM FLOW OF A LIQUID OVER A VERTICAL SURFACE IN A TRANSVERSE MAGNETIC FIELD

One of the actual problems of magnetohydrodynamics is the problem of the flow of electrically conductive liquids in thin liquid layers in the presence of a transverse magnetic field. Unfortunately, studies of these problems have not been sufficient so far. The influence of a transverse magnetic field can affect a number of factors: the change in the viscosity of the flow due to the magnetic field on the physico-chemical characteristics of the medium; manifestation of the effect of flow deceleration, which can have a significant effect on the hydrodynamic characteristics of the film flow in the processes of heat and mass transfer. In this regard, in this work was made an attempt to consider the influence of a constant magnetic field on the formation of a thin liquid layer on a vertical surface under the action of ponderomotive forces. As known, ponderomotive forces in the case under consideration can lead to a number of effects associated with a change in viscosity and flow deceleration. To a greater extent, this can manifest itself in thin liquid layers, depending on the ratio of gravitational forces, inertia forces and forces of a magnetic nature. An analysis of the influence of this phenomenon in the considered case of thin liquid layers, as shown in the work, significantly affects the length of the hydrodynamic initial section, the thickness of the liquid layer, and the damping of wave motion in the zone of stabilized flow. Recommendations for calculating these characteristics are presented in this article, in which much attention is paid to the definition of the liquid layer, depending on the ratio between the forces of inertia and the forces of a magnetic nature. An expression was also obtained for determining the distribution of velocities in the zone of a stabilized film flow in a transverse magnetic field. Thus, by comparing the expression for determining the distribution of velocities in a film without the influence of a magnetic field with the expression in the presence of a magnetic field, one can estimate the effect of ponderomotive forces on the flow of a liquid film.

Superspreading-Based Fabrication of Thermostable Nanoporous Polyimide Membranes for High Safety Separators of Lithium-Ion Batteries.

The development of thermally stable separators is a promising approach to address the safety issues of lithium-ion batteries (LIBs) owing to the serious shrinkage of commercial polyolefin separators at elevated temperatures. However, achieving controlled nanopores with a uniform size distribution in thermostable polymeric separators and high electrochemical performance is still a great challenge. In this study, nanoporous polyimide (PI) membranes with excellent thermal stability as high-safety separators is developed for LIBs using a superspreading strategy. The superspreading of polyamic acid solutions enables the generation of thin and uniform liquid layers, facilitating the formation of thin PI membranes with controllable and uniform nanopores with narrow size distribution ranging from 121±5nm to 86±6nm. Such nanoporous PI membranes display excellent structural stability at elevated temperatures up to 300°C for at least 1h. LIBs assembled with nanoporous PI membranes as separators show high specific capacity and Coulombic efficiency and can work normally after transient treatment at a high temperature (150°C for 20min) and high ambient temperature, indicating their promising application as high-safety separators for rechargeable batteries.

Nonlinear flow of couple stress fluid layer over an inclined plate

The issue of stability of a thin couple-stress liquid layer flows on an inclined plane was inspected. The thin-film approximation was employed to obtain a Benney-like differential equation, that described the time record of the interface profile The linear transition state and reduction ratio of maximum classical (Newtonian) growth-rate were discussed. The complete evolution equation was solved numerically using the method of lines in order to support the novelty of the work. The linear stability could be enhanced by increasing the couple-stress coefficient and surface tension as well as reducing the inclination. However, the ordinary viscosity played an irregular role. The linear results predicted conditions (windows) in which the non-Newtonian film was more stable than its Newtonian counterpart. The nonlinear stimulation anticipated the existence of sock waves in certain situations. The appearance of instability through the linear subcritical region as well as irregular influences with respect to surface tension and couple-stress property was revealed. The nonlinear approach was more accurate in describing the stability issue than the linear one. Such results could be employed to attain the optimum statuses with regard to the film stability, and control the shock waves. They would not only enable accurate practical implementation in the design of inertial confinement fusion capsules and supernova explosions and implosions modeling, but also would allow for precise numerical simulation.

Combined Effects of Chemical Reaction and Radiation on MHD Squeezing Flow of Casson Fluid

The impacts of chemical reaction on the magnetohydrodynamic (MHD) squeezing Casson fluid flow through a porous medium under the slip condition with viscous dissipation the presence of radiation parameter have been discussed. The flow is produced when two plates are compressed together in close proximity to one another. Using similarity variables may successfully convert partial differential equations (PDEs) to ordinary differential equations (ODEs). The shooting technique was used to perform the numerical analysis, which entailed solving the competent governing equations with dominating parameters for a thin liquid layer. This was done to determine the results of the study. It is essential to evaluate the numerical results in light of previously conducted research to validate the current answers. According to the results, an increase in the distance between the two plates leads to a rise in the velocity and the wall shear stress. The gas's velocity, temperature, and concentration all drop due to an increase in the Hartmann and Casson parameters. Both the temperature and the rate of heat transfer rise in direct proportion to the amount of viscous dissipation. In addition, it has been shown that the rate of mass transfer rises during destructive chemical interactions, but during constructive chemical reactions, the contrary occurs, which results in adverse effects.

Membraneless Ionic Liquid Droplet Nanoprobe for Vapor Sensing and Gas Phase Scanning Electrochemical Microscopy

Gas phase sensing of volatile chemicals is a critical area of research relevant to biomedical diagnosis and environmental hazard assessment. Among various types of sensors, electrochemical sensors garnered attention as cost-effective and portable methods. Most electrochemical sensors needed the membrane to prevent solvent evaporation for detecting the gaseous species. However, the presence of the membrane induced slow response time due to the penetration of gas molecules through the membrane. To improve the systems, a membraneless ionic liquid droplet nanoprobe was developed. Gaseous species can permeate the thin ionic liquid layer, which was also used as the electrolytes, and react on the electrode in extremely fast response. Furthermore, nano-sized electrode makes available to detect sensitively with low charging capacitance. Using the probe type form factor, application to gas phase scanning electrochemical microscopy (SECM) was attempted with high spatial resolution. Oxygen detection, the most commonly studied, was implemented for the first application of the ionic liquid nanoprobe. The limit of detection of this probe was 13 ppm, which is extremely good for electrochemical oxygen sensors. Also, the fast response (< 0.1 s) made the mapping of oxygen concentration using SECM. The nanoprobe showed more than a hundred times better spatial resolution (several micrometer scale) than the previous gas phase SECM study mapping the oxygen. As the application of this oxygen probe, Li-air battery analysis can be conducted. Oxygen was used in the reaction at the cathode of the Li-air battery. As mapping the oxygen concentration above the cathode, It is expected that structural causes for the irreversibility at the cathode can also be found. As oxygen sensing, other electrochemical active gaseous species can be detected with the electrochemical sensor. Trinitrotoluene is a well-known explosive compound, and it can be detected in electrochemistry. Due to its low vapor pressure, di-nitroaromatic compounds, like dinitrotoluene (DNT), dinitrobenzene (DNB), and dinitrophenol (DNP), were used as explosive footprints, which have higher vapor pressure and have often been identified as marker molecules. Using our ionic liquid nanoprobe, we developed the nitroaromatic compounds (NACs) sensor for real-time detection of trace vapors, without any sample pre-treatment and at room temperature. Furthermore, in a simulated airport carousel, real-time and preemptive NACs detection was demonstrated with fast response time. As oxygen detection, gas phase SECM was conducted and 3D mapping capability of the differential vapor pressure was demonstrated, exercising the potential of the NACs nanoprobe in locating the source of an explosive risk. With the sensitive sensing performance of nanoprobe, it can be used as breath analysis. There are several biomarkers to indicate certain diseases. For example, acetone is a representative biomarker of diabetes. Using this sensing platform, acetone sensing was implemented, and it may be used for the initial detection of diabetes.