Candle Combustion Research Articles

Candle soot colloids enhance tomato (Solanum lycopersicum) seed germination and seedling quality

The effect of candle soot colloids, a novel nanomaterial from candle combustion that we developed previously, on tomato (Solanum lycopersicum) seed germination and seedling vigor was investigated. Candle soot colloids were applied at different concentrations and hydrophobicities to tomato seeds and germination parameters and seedling vigor characteristics, such as length, fresh weight, dry weight, chlorophyll, and carotenoids, were measured. It was found that candle soot colloids significantly improved germination speed, seedling length, and seedling fresh weight compared to the control. The adherence of soot particles to the trichomes on the seed surface, which may help seeds retain moisture and stay hydrated, was observed. The chemical composition of the soot samples was analyzed using gas chromatography-time of flight mass spectrometry and two different chemical constituents in hydrophilic and hydrophobic soot samples that may affect seed germination were identified. A new potential use of candle soot colloids as plant growth-promoting agents and insights into the effects of nanomaterials on plant physiology and biochemistry were revealed by this study.

Heterogeneous interface engineering of N–doped carbon onion nanotube chains toward prominent microwave absorption

Synthesizing lightweight, thin–profile, and high–performance microwave absorbers has emerged as an urgent research topic. A promising strategy for carbon–based materials to achieve these attributes is to rationally construct heterostructures. Herein, 0.89–1.54 at.% nitrogen(N)–doped carbon onion nanotube chains (NCONCs) were produced by blending CONCs harvested from candle combustion with HH4Cl and subjecting them to heating at 300–400 °C for 3 h. The hinge–like NCONCs revealed numerous electron transport paths, facilitating the formation of multi–tiered conduction networks. The N–doping introduced C–N groups and interfaces into the CONCs, which yielded extensive dipole and interfacial polarization. Simultaneously, the 1.14 at.% N–doping endowed NCONC–400 with suitable conductivity, thereby ensuring excellent impedance matching. The resulting synergistic effect of impedance matching and electromagnetic wave attenuation was clearly observed. Specifically, NCONC–400 exhibited exceptional performance with a maximum effective absorption bandwidth of 4.71 GHz and a peak reflection loss of –35.47 dB at 1.4 mm. The radar cross–section reduction demonstrated by NCONC–400 composites reached 21.43 dB cm2. These impressive results prove the distinctive advantages of CONCs in tailoring performance and optimizing impedance matching, which are appealing for lightweight and efficient microwave absorbers.

Preparation of Superhydrophilic/Underwater Superoleophobic and Superhydrophobic Stainless Steel Meshes Used for Oil/Water Separation.

Robust membrane materials with high efficiency have attracted extensive attention in oil/water separation. In this work, carbon particles via candle combustion were firstly adsorbed on the surface of stainless steel meshes (SSMs), which formed a thin hydrophobic coating, and a rough structure was then constructed through chemical vapor deposition and high temperature calcination, with the resultant SSM surface wrapped with uniform silica coating possessing the characteristic of superoleophobicity underwater. Scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray powder diffraction (XRD) were used to characterize the modified SSMs. The prepared SSMs were superhydrophilic in air, and they had superoleophobicity underwater (157.4°). The separation efficiency of five oil/water mixtures was above 98.8%, and the separation flux was 46,300 L·m-2·h-1. After it was immersed in 1 mol/L NaOH, 1 mol/L HCl and 3.5 wt% NaCl for 24 h, respectively, the efficiency was still above 97.3%. Further immersion in the solution of dopamine and octadecylamine resulted in the transformation of superhydrophililc/superoleophobicity-underwater SSMs to superhydrophobic SSMs, and the resultant SSMs with reverse surface wettability was also used for the oil/water separation with good separation efficiency and separation flux.

Transparent and durable PDMS(O)/HDTMS anti-icing surfaces derived from candle soot

Preventing icing on exposed surfaces is important in our daily life. However, the transparent and durable anti-icing coating is still a challenge. In this work, we demonstrated a transparent oxidized polydimethylsiloxane/hexadecyltrimethoxysilane (PDMS(O)/HDTMS) coating on slide by using the candle soot (CS) as a sacrificial template. The CS as a product of incomplete combustion of candles with a porous network chain structure was firstly deposited on the PDMS coated slide. After a calcination treatment, the CS was removed while the PDMS layer was oxidized and inherited the unique structure of the CS and became transparent and superhydrophilic. With the help of the HDTMS modification, the final PDMS(O)/HDTMS coating exhibited surperhydrophobic property (WCA = 163°, SA < 1°). The coating can preserve its surperhydrophobic state after different mechanical abrasion, acid/base, UV light exposure and icing/thawing cycles. Beneficial from its surperhydrophobic feature, the coating not only postponed the freezing time of the water droplet from 229 to 1022 s, but also enabled the ice slide away by gravity. In addition, the PDMS(O)/HDTMS was successfully used on the glass insulator to delay the ice accumulation. This work provides a facile and environmentally-friendly method to obtain transparent and durable anti-icing coating.

Flame synchronization and flow field analysis of double candles

Flame instability is an interesting topic in combustion science, and it is also of great practical significance for designing high-performance burners. In recent years, the synchronization phenomenon caused by a pair of coupled candles has aroused widespread attention, among which in-phase and anti-phase are two notable examples. In order to understand the flow structure of the flashing flame and the reasons for the synchronization of the flame oscillator, COMSOL flow field analysis technology and MATLAB grey analysis technology were used to analyze the flow field of candles in three combustion states and the change of candle combustion state respectively. By analyzing the flow structure of flashing flame, the reasons of different burning states of candles are explained. Moreover, the experimental and numerical simulation results show that the in-phase mode is characterized by the symmetrical formation of vortex concerning the centerline of two groups of flames, and the flames are vertically stretched under the vortex action. The characteristic of the anti-phase mode is that the vortex alternately forms asymmetrically concerning the centerline of two groups of flames, and the non-uniformity and asymmetry of the vortex lead to the instability of the flame surface. The characteristic of the incoherent mode is that the vortices generated by the two candle groups no longer act on each other, and the airflow field between the two candle groups remains approximately unchanged.

Research on the Synchronization Problem in the Combustion of Candles

In 2020, IYPT question 5 “synchronized candles” describes an interesting common phenomenon in life. The so-called synchronous candle refers to the flame that can be observed to oscillate when several adjacent candles are burning. Two such oscillations can be coupled with each other, leading to in-phase or reverse phase. In this paper, the control variable method is used to study the reason of the oscillation of a single oscillator and the phenomenon of inphase or anti phase oscillation of candles with different separation distance. It is found that the phenomenon of the oscillation coupling of regular candles is related to the distance between candles. Considering that the gas diffusion coefficient of the air is too low and the isotherm of the candle is relatively stable, the most likely cause of synchronization or inverse synchronization is thermal radiation. Finally, FDS software is used to simulate the combustion of the flame, and the results of in-phase and inverse vibration are also obtained.

Anaerobic culture on growth efficient bi-layered culture plate in a modified candle jar using a rapid and slow combustion system

Success for maximum isolation of anaerobes depends on maintaining critically low oxygen levels throughout and growth in a reduced medium with exclusion of inhibitory substances. Hence a dual system was used equipped with candle combustion for instant exhaustion of major part of oxygen from a sealed jar, along with acidified steel wool for residual oxygen purging. For inhibitory substances removal, test anaerobes were grown on anaerobic medium layered on buffer charcoal agar bed. After 48 hours incubation average colony sizes were compared with that of growths in conventional Gas-Pak system. Better growths were noted in the innovative system.

Detachment of Submicron Particles from Substrates Using the Suspension-Assisted Ultrasonic Method

A protocol for the detachment of solid samples deposited on flat substrates and their collection in aqueous samples is proposed based on a suspension-assisted ultrasonic method. As samples, combustion-synthesized magnesium oxide aggregates in the submicron size range were deposited in the gas phase onto three kinds of substrates: a silicon wafer and coarse and fine alumina-coated resin sheets. To enhance the sample particle detachment, a solid–liquid suspension made of candle combustion soot particles was selected as an ultrasound propagation medium, which is different from the usual liquid medium, such as water, a surfactant solution, or a solvent. Preliminary detachment experiments were performed using low-power (42 kHz and 35 W) ultrasonication, and the substrates and suspensions were analyzed using scanning electron microscopy (SEM) images and particle size distributions based on dynamic light scattering, respectively. The detachment efficiency, defined as the fraction of cleaned area on a substrate, was determined from the SEM images and indicates that the detachment using the medium with soot had a higher efficiency compared to that without soot, and there was an optimum soot concentration for particle detachment for all three substrates. The suspension particle size distribution after ultrasonication showed good dispersion of the sample particles in the soot suspension.

Theoretical and experimental substantiation of the system of local removal of harmful substances during the combustion of candles in the worship hall of Orthodox churches and cathedrals

The analysis of the features of Orthodox churches, temples and cathedrals, elements of the design of the halls of worship, and their preservation. The types of hazards generated during the burning of candles and the parishioners and staff present are systematized. Thermal imaging surveys of convective flows formed during candle combustion were carried out. A technique for conducting experiments and a diagram of an experimental setup for measuring the temperature and air velocity in a convective jet have been developed. The diagram of the convective flow structure is presented, which consists of individual jets from each candle. The results of the study have been obtained, which make it possible to determine the area of stable convective flow and the place of installation of the exhaust hood above the candlestick, as well as the distance between the burning candles and the edge of the bottom of the umbrella. A local mechanical exhaust ventilation system with umbrellas has been developed to trap and remove harmful substances from the worship hall and provide comfortable conditions for parishioners and preserve the decoration elements of the halls. The characteristics and conditions for the efficient operation of the hoods in the local exhaust ventilation system and the factors influencing their operation are given.

Behind the Candelabra: A Facile Flame Vapor Deposition Method for Interfacial Engineering of Garnet Electrolyte To Enable Ultralong Cycling Solid-State Li-FeF3 Conversion Batteries.

The frustrating interfacial issue between Li metal anode and solid electrolyte is the main obstacle that restricts the commercial promotion of solid-state batteries. The garnet-type ceramic electrolyte with high stability against metallic Li has drawn much attention, but it also suffers from huge interfacial resistance and Li dendrite penetration due to the unavoidable formation of the carbonate passivation layer and limited interface contact. Herein, we propose a facile and effective method of flame vapor deposition to spray candle soot (CS) coating on the garnet surface. It enables the reduction of the carbonate layer and the conversion to a highly lithiophilic interlayer especially when in contact with molten Li. The lithiophilicity is rooted in the enrichment of graphitic polycrystalline domains in CS, which can be chemically or electrochemically lithiated to form the ionic/electronic dual-conductive network containing LiC6 moieties. The CS interlayer binds the Li metal with the garnet electrolyte tightly with gradual transition of Li-ion conductivity, leading to a significant reduction of the area-specific resistance to 50 Ω cm2 at 60 °C with high cycling and current endurance. Garnet-based symmetric cells and solid-state full cells conducting this strategy exhibit impressive electrochemical reversibility and durability under the preservation of the compact interface and smooth Li plating/stripping. The modified Li/garnet/FeF3 batteries exhibit a discharge capacity as high as 500 mA h g-1 and long-term cyclability for at least 1500 cycles (with capacity preserved at 281.7 and 201 mA h g-1 at 100 and 200 μA cm-2, respectively). This candle combustion strategy can be extended to more ceramic electrolytes compatible with high-temperature pretreatment.

Effect of non-collimated light path on flow field's temperature reconstruction by moiré tomography

In this paper, the effect of non-collimated light path on flow field's parameter diagnosis by moiré tomography is discussed, and a candle combustion flow field is chosen for experiment. To obtain the non-collimated light path, a little lens which is used for beam expanding and collimation is equidistantly moved twice to the left (near the light source) and right (away from the light source) on the basis of the collimated position. Therefore, for a certain cross section, five sets of moiré fringes can be obtained from experiment for further analysis and discussion. And, three cross sections of the measured candle combustion are chosen for practical discussion. The results manifest that the moiré fringes are tilt to the right when the little lens moves to the left, and the temperature is larger than that of obtained by the collimated light path. Meanwhile, it is found that the moiré fringes are tilt to the left when the little lens moves to the right, and the temperature is smaller than that of obtained by the collimated light path. Finally, the possible factors which could affect the measurement accuracy of OCT methods for diagnosing flow fields are discussed.

Phase information extraction for moiré fringes based on multiresolution analysis.

In this paper, the multiresolution analysis (MRA) method is used to preprocess moiré fringes, which can reduce the number of data points and increase computation speeds. To discuss the applicability of the method, a candle combustion flow field is chosen as an example for experiment by moiré deflectometry. First, moiré fringes are preprocessed by the MRA method. Then, phase information extraction and refractive index reconstruction are performed on the three-level low-frequency approximation components. Finally, the involved results prove that the calculation time required for phase information extraction and refractive index reconstruction is greatly reduced based on the moiré fringes preprocessed by MRA method. The relative error could be accepted if the suitable approximation level is applied.

Frequency and Phase Characteristics of Candle Flame Oscillation

The combustion of candles exhibits a variety of dynamical behaviors. Binding several candles together will result in flickering of candle flames, which is generally described as a nonlinear oscillator. The impact on the frequency of the flame by several factors, such as the arrangement, the number and the asymmetry of the oscillators, is discussed. Experimental results show that the frequency gradually decreases as the number of candles increases in the case of an isolated oscillator, while alternation between the in-phase and the anti-phase synchronization appears in a coupled system of two oscillators. Moreover, envelopes in the amplitude of the oscillatory luminance are displayed when candles are coupled asymmetrically. Since the coupling between oscillators is dominated by thermal radiation, a “overlapped peaks model” is proposed to phenomenologically explain the relationship between temperature distribution, coupling strength and the collective behavior in coupled system of candle oscillators in both symmetric and asymmetric cases.

Telomere shortening and aortic plaque progression in Apoliprotein E knockout mice after pulmonary exposure to candle light combustion particles.

Particles from burning candles contribute to the overall indoor exposure to particulate matter (PM). However, little is known about the effects of indoor sources of particles on cardiovascular disease endpoints. This study investigated the effect of pulmonary exposure to particles from combustion of candles and progression of atherosclerosis. Telomere shortening was assessed in tissues due to its relationship to risk of cardiovascular diseases. The particles were collected from burning candles and used for toxicological studies in cultured endothelial cells and apolipoprotein E (ApoE) knockout mice. Three hours exposure to particles increased the production of reactive oxygen species in endothelial cells, whereas there was no effect on cytotoxicity. Intratracheal instillation of particles (0.5 or 5 mg/kg) once a week for 5 weeks in ApoE-/- mice was associated with an accelerated progression of atherosclerosis in aorta and telomere shortening in the lung and spleen, whereas there was no effect on inflammation in the lungs (i.e. cell numbers), cell damage (i.e. lactate dehydrogenase) and lung barrier damage (i.e. protein concentration) as measured in bronchoalveolar lavage fluid. The results indicate that particles from burning candles are hazardous and this indoor emission source is an important contribution to the health risk of exposure to PM.

Carbonaceous Nanoparticle Layers Prepared using Candle Soot by Direct- and Spray-based Depositions

To investigate the properties and structures of soot particles derived from candle combustion, two deposition routes were performed. In Route-1,” the aerosol (soot) particles were collected by direct exposure of a substrate in a chamber with controlled airflows. In Route-2,” deposited soot nanoparticles was transferred into suspension and subsequently, the deposition of particles on to the substrate was achieved by an electrospray. Raman spectral analysis has shown the difference of G-band intensity relative to D-band between hydrophobic and hydrophilic particle layers obtained from different collection regions of the candle flame. It also reveals the effect of airflows during the collection to the ratio of the D to G peak. Meanwhile, the Raman spectra of the particles seem invariant to the preparation methods of suspension and electrospray deposition process. From the curve gradient of spectroscopy (190–2500 nm) results, the electrospray-deposited particle layers (Route-2) show higher absorbance in the near-infrared region compared to direct-deposited particle layers (Route-1). This change in the spectrum may due to the change in morphology of nanoparticle layers formed by each route.

Facile design of superhydrophobic and superoleophilic copper mesh assisted by candle soot for oil water separation

Oil water separation techniques have attracted more and more attention due to the increasing accidents of oil spills in marine transportation, food, and other industry fields. Oily waste water and water-cut oil are harmful to the ecological environment and human health. However, traditional separation methods posed low efficiency and high cost. So low cost, simple process and high efficiency separation materials are urgently needed. In this work, a low cost carbon nanoparticles acted as hydrophobic materials were used to modify rough copper mesh during the candle combustion. Surface morphology was observed by scanning electron microscope (SEM), and surface wettability was tested by contact angle (CA) meter.Experimental results showed that water CA of the mesh after modification were above 150°, and oil CA is less than 5°, which showed good super-hydrophobicity and superoleophilicity. Additionally, the modified mesh also exhibited pronounced chemical stability, thermal stability, corrosion resistance, and oil/water separation properties with high oil flux (4378Lm−2h−1) and oil–water separation efficiency (>90%). Moreover, the modified mesh posed high separation efficiency and oil flux after 30 reused cycles. The modification process is short time consuming and low cost without any organic reagent and complicated chemical reaction. Therefore, it is believed that the facile fabrication proposed in this work may provide a novel strategy for oil water separation membrane and make the modified mesh a promising tool for application in oil-water separation.

Isolation of bacteria from diabetic foot ulcers with special reference to anaerobe isolation by simple two-step combustion technique in candle jar.

Background & objectives:Although polymicrobial infections involving both aerobic and anaerobic bacteria are very common in diabetic foot ulcers, in many centres of developing countries, anaerobes are rarely isolated due to technical difficulties. This can be overcome by using a new simple, innovative technique of a combination of candle combustion and use of acidified copper-coated steel wool, as reported here.Methods:In-house developed method was used in a prospective clinico-microbiological study for anaerobes from randomly selected 43 patients with diabetic foot ulcers along with conventional method of anaerobic culture in GasPak system and aerobic culture by standard laboratory procedures. For primary isolation of anaerobes, Brucella blood agar supplemented with hemin (5 μg/ml) and menadione (1 μg/ml) was used. Antibiotic sensitivity tests were performed by the standard disc diffusion method for aerobes and E-test method for anaerobes.Results:All the 43 samples were culture positive, of which aerobic Gram-negative bacteria (GNB) predominated, followed by Staphylococcus aureus, Enterococcus and diphtheroids. Anaerobes isolated from 21 samples were Peptostreptococcus, Bacteroides, Porphyromonas, Veillonella spp. and Clostridium perfringens by both GasPak and in-house developed and modified candle jar techniques. Imipenem and metronidazole were most sensitive while clindamycin, penicillin and cefoxitin were least sensitive drugs for anaerobes. Aerobic GNB were found to be multidrug resistant, especially to penicillin and cephalosporins. The most sensitive drug was piperacillin-tazobactam.Interpretation & conclusions:For isolation of anaerobes from clinical specimens such as diabetic foot ulcers, modified candle jar technique was found to be as reliable as GasPak system. This modified technique needs to be tested for many other clinical materials which are not yet evaluated.

Preparation of superhydrophobic and superoleophilic nanostructured layer on steel mesh for oil-water separation

Abstract Recently, fabrication of hydrophobic materials with application in oil spill cleanup becomes a new research focus. Herein, we report the preparation of superhydrophobic and superoleophilic steel mesh covered with nanostructured organic film for oil and organic solvents collection from water surface. The superhydrophobic mesh was fabricated by a simple deposition of carbon soot (CS) nanospheres on the steel mesh using candle combustion flam, followed by vapour phase deposition of polypyrrole (ppy). Finally the surface was modified with stearic acid (SA). The topological structure and surface wettability of the prepared mesh were characterized by SEM, FT-IR, Raman spectra and contact angle measurements. The prepared hydrophobic mesh was shaped as a miniature boat which can float on water surface and absorbs various oils from water surface very fast. Additionally, the miniature boat could be reused for many times in the oil-water separating process without decreases of its separation ability. The results illustrate that the prepared hydrophobic mesh is, low cost and can be used for facile and rapid collection of oil and other organic solvent from water surface.

Introduction to Problems of Candle Combustion in Buildings

From the earliest times of human history are used portable light sources. First advanced devices were torches and candles, and then human population started using kerosene lamps and other more sophisticated portable light sources based on biology or electricity. Light source based on a chemical reaction has one common denominator and that is the release of fumes while fuel combustion. In these cases, it is the source of its own, which is referred to such bodies or substances in which structure is formed light. Nowadays, historically valuable buildings more often server different purpose than they were originally built. This change in use can lead to a significant influence on historical building and its life span. One of the many factors negatively affecting the life of monuments are fumes from candle combustion. Massive use of candles releases toxic substances into the environment, which in high concentrations can affect human health and can also damage due to chemical reactions historically valuable monuments

Exposure of scented candle combustion aerosol on stress-induced cadiopulmonary injury

Background: Social stress may induce cardiopulmonary injury by disrupting the body’s homeostasis. Scented candles have been used to relieve stress. However, numerous air pollutants produced from burning scented candles may cause poor health outcomes. Aims: To investigate effects of scented candle combustion products exposure on social stress-induced cardiopulmonary injury in mice. Methods: Mice with social disruption stress (SDR) were exposed to combustion products of 3% lavender scented candles (4.5 h/d, 5 d/wk) in an exposure chamber for different time course (4 or 8 wk). Results: Exposure to combustion products of scented candle failed to reduce serum corticosterone level in SDR-treated mice in 4 and 8 weeks. Exposure to combustion products of scented candle time-dependently enhanced SDR-induced pulmonary edema, tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, interleukin (IL)-1beta levels, and nuclear factor (NF)-kB activity in lung. Further, combustion products of scented candle time-dependently increased lactic dehydrogenase, creatine phosphokinase, and heart type creatine kinase isoenzyme levels in serum, hypoxia-inducible factor (HIF)-1alpha, and B-type natriuretic peptide levels in SDR-treated mice. Conclusions: Exposure to combustion products of 3% lavender scented candle may time-dependently exacerbated social stress-induced cardiopulmonary injury.