Effects Of Chemical Inhibition Research Articles

Inhibition of Atm and Atr kinases affects embryo development and the DNA damage response in sterlet (Acipenser ruthenus)

Embryo development is regulated by numerous interconnected pathways that direct cell fate, differentiation, and genetic stability. During development, these pathways can be altered by exogenous factors, such as pollutants, or endogenous factors, such as replication stress. Ataxia telangiectasia mutated (Atm) and ataxia telangiectasia and Rad3-related (Atr) kinases play critical roles in regulating the cell cycle, the DNA damage response (DDR), DNA repair, checkpoint activation, and apoptosis. In cells with damaged DNA, these kinases can slow the cell cycle to provide the necessary time and ability for DNA repair. In this study, we investigated the roles of Atm and Atr in embryo development and DDR in the sterlet (Acipenser ruthenus). Sterlets belong to the Acipenseridae family, one of the most threatened groups of species. Thus, understanding their genetics, biology, embryogenesis, and conservation is crucial. Furthermore, the sterlet is a significant aquaculture species that represents an intriguing model for studying polyploidy and genome plasticity. In our research, we examined the effects of chemical inhibition of Atm and Atr on sterlet embryo development in the absence and presence of the genotoxicant camptothecin (CPT). Our findings indicated that in the absence of genotoxic challenge, Atr autophosphorylation increases between 1 and 3 days post-fertilization (dpf) and decreases by 5 dpf, illustrating the involvement of Atr in the response to replication stress in rapidly differentiating tissues during the early stages of embryo development. Conversely, Atm inhibition was associated with a dose-dependent reduction in embryo viability, highlighting its importance in normal embryo development. When sterlet embryos were exposed to CPT, both Atm and Atr were involved in DDR and the activation of apoptosis. Notably, when both kinases were inhibited simultaneously, the embryos lost their ability to induce apoptosis and mitigate DNA damage, resulting in 100% embryonic mortality. These results suggest that Atm and Atr have distinct functions during normal embryo development, but they can partially complement each other in DDR.

MXene‐CeO2@PDA Synergistically Enhanced Anticorrosion of Waterborne Epoxy Coating

AbstractDeveloping ecofriendly anticorrosion coating has great demand for marine protection. Incorporation of nontoxic inorganic fillers into waterborne epoxy (WEP) coating shows tremendous potential for enhancing corrosion resistance. However, the application of MXene/WEP coating is limited by the poor dispersion of MXene in WEP and insufficient corrosion resistance. Herein, a polydopamine (PDA) modified MXene‐CeO2@PDA (MCP) filler is constructed by a combination of CeO2 with MXene and embedded into WEP to form ecofriendly anticorrosion MCP/WEP coating. Dispersion of MXene in WEP is improved by the introduction of CeO2 and PDA modification. Benefiting from the synergy of the physical labyrinth effect of MXene and the chemical inhibition effect of CeO2, MCP/WEP coating exhibits remarkable anticorrosion behavior in 3.5 wt% NaCl solution with a low corrosion rate (CR) of 4.48 × 10−6 mpy, which is three orders of magnitude lower than that of blank WEP (4.78 × 10−3 mpy). Moreover, MCP/WEP presents long‐term and stable corrosion protection for over 30 days. The results reveal the incorporation of MCP significantly promotes the anticorrosion performance of WEP.

The preparation and fire extinguishing mechanism research of a novel high-efficiency KHCO3 @HM dry powder

Hydromagnesite (HM) is a widely distributed primary natural carbonate mineral. To expand the application range of hydromagnesite and tap its fire-extinguishing potential, a new type of high-efficiency KHCO3 @HM dry powder was prepared by coating potassium bicarbonate on the surface of hydromagnesite with a dip coating method. KHCO3 @HM dry powder obtained a chemical inhibition effect through this method, and the fire extinguishing efficiency has been further improved. A series of tests were carried out to confirm the excellent physical and chemical inhibition effect of KHCO3 @HM dry powder. Specific surface area tests showed that the specific surface area of KHCO3 @HM dry powder (31.405 m2/g) was higher than NH4H2PO4 dry powder (12.766 m2/g). Flowability tests showed that KHCO3 @HM dry powder (0.04 g/s) achieved the same flowability as NH4H2PO4 dry powder (0.04 g/s). Local oil basin fire experiments showed that the average fire extinguishing time of KHCO3 @HM dry powder was shorter with less powder consumption. Under 0.2 MPa driving pressure, the fire extinguishing time of KHCO3 @HM dry powder was 2.2 s faster than NH4H2PO4 dry powder, and the dry powder consumption was 3.71 g less than NH4H2PO4 dry powder. The cooling effect of KHCO3 @HM dry powder (208 ℃) in 10 s was better than NH4H2PO4 dry powder (157 ℃), and KHCO3 @HM dry powder (399 ppm) showed a better smoke suppression effect than NH4H2PO4 dry powder (545 ppm). The pyrolysis of KHCO3 @HM dry powder reduced the fire temperature, diluted the oxygen concentration, and captured free radicals. The final pyrolysis products formed a thick oxide film to provide good heat insulation and asphyxiation effects. The excellent cooling, dilution, asphyxiation, and chemical inhibition mechanisms of KHCO3 @HM dry powder were demonstrated, and finally achieved a comprehensive performance comparable to NH4H2PO4 dry powder.

Lipid-nanoparticles-based co-delivery of black phosphorus quantum dots and melphalan by photothermal therapy combined with chemotherapy for retinoblastoma

Melphalan is an efficient chemotherapeutic agent for retinoblastoma (RB) in clinical practice. However, the problems of drug resistance and poor prognosis caused by long-term treatment of melphalan should not be ignored. At present, it is urgent to find a therapeutic strategy to enhance the curative effect to solve the need for clinical treatment of RB to protect eyesight. Herein, we propose an effective strategy to encapsulate melphalan and black phosphorus quantum dots (BPQDs) with high-biocompatibility liposomes for photothermal therapy (PTT) to enhance cell killing. BPQDs and melphalan were encapsulated using liposomes with a similar structure to the cell membrane, and a lipid nanoparticle with both photothermal and chemical inhibition effects was prepared. The obtained nanoparticle has a spherical shape (particle size range of 82–180 nm) and good stability (encapsulation efficiencies of melphalan of 40 % and BPQDs of 43.7 %). Its temperature increased to 65 °C within 10 min under a 2 W/cm2 laser at 808 nm, exerting photothermal and synergistic effects with melphalan to induce apoptosis of tumor cells. As expected, the prepared nanoparticle effectively inhibits tumor proliferation, upregulates the ki67 expression level, and has an excellent PTT effect on the orthotopic xenograft of WERI-RB-1 cells.

Experimental study on exploration of optimum extinguishing agent for 243 Ah lithium iron phosphate battery fires

Nowadays, an effective and clean extinguishing agent or technology is highly desirable for lithium-ion battery (LIB) fires. Herein, the physicochemical properties and extinguishing effects of various extinguishing agents on 243 Ah lithium iron phosphate (LFP) battery fires are investigated systematically. The extinguishing mechanisms are deeply analyzed and the performance is comprehensively evaluated from the aspects of thermal runaway (TR) and toxicity suppression, cooling and extinguishing efficiency. Compared with HFC-227ea, C6F12O can absorb more heat through vaporization, thereby improving extinguishing and cooling efficiency. The lack of chemical inhibition effect and the tiny droplet size make water mist unable to suppress the high-temperature jet fire, but it has the lowest toxicity and highest cooling efficiency of 54.6%. F-500 and FireIce can improve the extinguishing performance of the water mist by encapsulating and taking hydrocarbon fuel away from the fire zone and inhibiting free radicals in the flame, respectively. 3% F-500 has the extinguishing efficiency of 78.4% and TR efficiency of 64.1%, while maintaining the cooling performance well. In the future, a novel type of fire-extinguishing agent with high heat capacity and latent heat, excellent extinguishing performance, high wettability, low toxicity and insulating properties is expected to be developed for LIB fires.

Effects of chemical inhibition of histone deacetylase proteins in the growth and virulence of Macrophomina phaseolina (Tassi) Goid.

Chromatin remodeling enzymes are important “writers”, “readers” and “erasers” of the epigenetic code. These proteins are responsible for the placement, recognition, and removal of molecular marks in histone tails that trigger structural and functional changes in chromatin. This is also the case for histone deacetylases (HDACs), i.e., enzymes that remove acetyl groups from histone tails, signaling heterochromatin formation. Chromatin remodeling is necessary for cell differentiation processes in eukaryotes, and fungal pathogenesis in plants includes many adaptations to cause disease. Macrophomina phaseolina (Tassi) Goid. is a nonspecific, necrotrophic ascomycete phytopathogen that causes charcoal root disease. M. phaseolina is a frequent and highly destructive pathogen in crops such as common beans (Phaseolus vulgaris L.), particularly under both water and high temperature stresses. Here, we evaluated the effects of the classical HDAC inhibitor trichostatin A (TSA) on M. phaseolinain vitro growth and virulence. During inhibition assays, the growth of M. phaseolina in solid media, as well as the size of the microsclerotia, were reduced (p<0.05), and the colony morphology was remarkably affected. Under greenhouse experiments, treatment with TSA reduced (p<0.05) fungal virulence in common bean cv. BAT 477. Tests of LIPK, MAC1 and PMK1 gene expression during the interaction of fungi with BAT 477 revealed noticeable deregulation. Our results provide additional evidence about the role of HATs and HDACs in important biological processes of M. phaseolina.

Montmorillonite Powder and Its Hydroxyl Modified Powder Experimental Study on the Inhibition of Lycopodium Powder Explosion

ABSTRACT In order to seek a better inhibitor to suppress the explosion of lycopodium powder, this paper used Hartmann experimental system and 20 L spherical explosion experimental system to conduct the flame propagation and explosion pressure suppression experiments of lycopodium powder explosion, respectively, to study the suppression effect of lycopodium powder explosion under the conditions of adding different proportions of montmorillonite powder and hydroxy modified montmorillonite powder, combined with the FTIR curves before and after the explosion of lycopodium powder as well as the reaction involving it and inhibitors, the inhibition mechanism of montmorillonite powder and hydroxy- montmorillonite powder on the explosion of lycopodium powder was analyzed. The experimental results show that: with the increase of the addition ratio of the two inhibitor powder, the flame brightness becomes darker, the flame propagation speed gradually decreases, and the maximum explosion pressure and the maximum explosion pressure change rate gradually decreases. By the analysis of inhibition mechanism: montmorillonite powder blocks and absorbs thermal radiation and has basically no chemical inhibition effect whose inhibition effect is relatively weak; hydroxy-montmorillonite powder in addition to the basic physical inhibition with montmorillonite powder, but also decomposition at high temperatures to generate a large number of hydroxyl radicals, the radicals generated can make the reaction of the explosion in the reverse direction, and nearly can block the explosion chain reaction continues, playing a key role in chemical inhibition. Research results show that: montmorillonite powder and hydroxyl modified montmorillonite powder on lycopodium powder explosion have a certain inhibition effect, and modified hydroxyl montmorillonite powder than montmorillonite powder on the lycopodium powder explosion inhibition effect is better.

Abstract 3554: Targeting chromatin remodeling complex in pediatric cancers

Abstract Chromatin accessibility plays critical roles in maintaining normal gene regulatory programs in healthy tissue. Aberrant chromatin accessibility triggered by abnormal activity of a variety of chromatin remodeling complexes is known to activate and maintain tumor proliferation. The most widely known of these complexes is the SWI/SNF (also called BAF) complex. Studies have shown that BAF regulates chromatin accessibility in a more global manner and its long-term inhibition or functional loss may lead to non-specific downstream effects in both tumor and normal tissue. Thus, there is a need to further probe understudied complexes, such as the Imitation Switch (ISWI) family of chromatin remodelers, to find more cancer specific functions that can provide mechanistic insights that pave the way for novel therapeutic discoveries. We have examined the functions of these chromatin complex in different type of pediatric cancers to estsablish the pre-clinical rationale for potential novel pediatric cancer therapy. We discovered that fusion protein positive rhabdomyosarcoma (FP-RMS), an aggressive sub-type of RMS characterized by chromosomal translocations resulting in gene fusions between PAX3/7 and FOXO1 is highly dependent on chromatin accessibility. This aggressive subtype exhibits a significant vulnerability in its dependence on the oncogenic transcription factor PAX3-FOXO1, yet like many other TFs, PAX3-FOXO1 is currently not considered a viable therapeutic candidate. We have then carefully examined the effect of chemical inhibition and chemical degradation of BAF complex function in FP-RMS and discovered that BAF complex globally regulates chromatin accessibility, is not specifically regulating FP function. We next examined the function of other chromatin remodeling complexes that might regulate FP function specifically in FP-RMS. We identified that some of other chromatin remodeling complex, such as Nuclear Remodeling Factor (NURF) complex, a member of the ISWI chromatin remodeling complex family, interacts with a critical fusion protein, PAX3/7-FOXO1, in FP-RMS. There is limited understanding surrounding the functions of NURF complex, particularly in pediatric cancer. Here, we then studied the key functions of FP regulated by variety of chromatin remodeling complex utilizing combined chemistry and biology method to elaborate the essential functions of PAX3/7-FOXO1 fusion protein. We have developed variety of chemical strategies to target these complexes, and utilize these tool compounds to delineate the chromatin remodeling complex regulated FP functions. This study showcased our approach to advance cancer research by combining the power of chemistry, chemical biology, structural biology, computational biology and cellular biology to identify novel mechanistic understanding as well as novel therapeutic approach for pediatric cancers. Citation Format: Jun Qi. Targeting chromatin remodeling complex in pediatric cancers. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3554.

Effects of fire extinguishing agents on pyrolysis and explosion characteristics of optical brightener dust

As a widely used optical additive, optical brightener has a potential risk of dust explosion during production and utilization, which limits its further application. In this paper, the pyrolysis process and explosion characteristics of universal optical brightener OBA-184 dust were studied, and the inhibition effects of NH4H2PO4, NaHCO3, and aerosil (nano-silica) were compared using the Hartmann tube and the 20-L spherical explosion system. The results illustrate that OBA-184 dust is a substance with huge heat of decomposition. All three extinguishing agents can effectively moderate the ignition sensitivity and explosion severity. Among them, NH4H2PO4 has the best efficiency in suppressing explosion severity due to its excellent chemical inhibition effect. The complete inert ratio of NH4H2PO4 was about 60% lower than that of NaHCO3, while aerosil can not completely inert the OBA-184 dust at the inert ratio in the range studied. NaHCO3 can significantly reduce the ignition sensitivity of OBA-184 dust, and adding 60% NaHCO3 can reduce the dust to a low sensitivity level. Inerting is accomplished due to its low decomposition temperature and violent heat absorption rate; Aerosil is less effective than NH4H2PO4 and NaHCO3, which attributes to its poor physical heat absorption and weak chemical inhibition ability. The results of this paper provide a theoretical and practical basis for dust explosion prevention and control in the optical brightener industry.

Flame propagation inhibition study on methane/air explosion using CO2 twin-fluid water mist containing potassium salt additives

In order to improve the explosion suppression efficiency, experiments were conducted on a self-built visual half-open explosion pipe to study the synergistic explosion inhibition effect of CO2 twin-fluid water mist containing potassium salt additives. Results showed that: the inhibition effect of CO2 twin-fluid water mist with potassium salt additive increased with the spraying time, the peak overpressure and flame speed declined obviously, and the brightness of the flame was lower or even disappeared, indicating the flame propagation was better blocked. Comparing to 5s CO2 twin-fluid water mist, after the addition of 6% K2CO3, the maximum overpressure and flame speed reduced by 28.87% and 15.07% respectively, and the arrival time of the flame to the end of the pipe prolonged by 21.57%. The inhibition order of CO2 twin-fluid water mist containing four potassium salt additives from high to low is K2CO3> K2C2O4> KCl > KH2PO4. The number of flame free radicals O, H, OH in the whole explosion system decreased significantly under the inhibition of CO2 twin-fluid water mist containing potassium salt additive, indicating potassium salt additive and CO2 twin-fluid water mist have a synergistic effect on inhibiting gas explosion, which can enhance the physical and chemical inhibition effect on flame propagation.

Topoisomerase 1 inhibition modulates pyroptosis to improve recovery after spinal cord injury.

Excessive neuroinflammation and neuronal loss contribute to mechanisms of spinal cord injury (SCI). Accumulating evidence has suggested that topoisomerase 1 (Top1) inhibition can suppress exacerbated immune responses and protect against lethal inflammation. Pyroptosis is a recently identified pro-inflammatory programmed mode of cell death. However, the effects and underlying mechanisms of Top1 inhibition in SCI remains unclear. Locomotor functional recovery in mice was evaluated through Basso Mouse Scale (BMS). Neuronal loss was evaluated by immunochemistry staining of NeuN. Pyroptosis was determined by immunofluorescence staining, western blot, flow cytometry, cell viability, and cytotoxicity assays. In the present study, we estimated the effects of chemical inhibition of Top1 in an SCI model. Administration of Top1 inhibitor camptothecin (CPT) to mice significantly improved locomotor functional recovery after SCI. Moreover, CPT reduced Top1level, inhibited nucleotide-binding oligomerization domain-like receptor 3 (NLRP3) inflammasome activation and pyroptosis, attenuated proinflammatory cytokines levels, diminished the number of neutrophil and neuronal loss in mice. Furthermore, CPT in oxygen-glucose deprivation neurons down-regulated Top1level, attenuated NLRP3 inflammasome activation, and suppressed pyroptosis and inflammatory response. Together, our findings indicate that inhibition of Top1 with CPT can inhibit pyroptosis, control neuroinflammation, and improve functional recovery after SCI.

Synthesis and application of temperature‐sensitive polymer as a novel plugging agent for water‐based drilling fluids

AbstractIn the process of drilling with water‐based drilling fluid, polymer plugging agent is very important to solve the problem of wellbore instability in the formation with micropores and microfractures. In this study, N‐isopropyl acrylamide and 2‐acrylamide‐2‐methylpropanesulfonic acid were grafted onto the surface of SiO2 modified by vinyl trimethoxysilane by reverse suspension polymerization reaction, and a heat‐sensitive polymer plugging agent was synthesized. The structure analysis showed that the synthetic material was the target product, with a particle size of 49.665 μm, high‐temperature resistance and sensitive temperature response behavior. According to laboratory evaluation experiments, it can be seen that the addition of the polymer increased the electrostatic stability of bentonite particles and had a chemical inhibition effect. Under the action of temperature and pressure, the synthesized temperature sensitive plugging agent formed a dense hydrophobic membrane on the surface of mud cake, which physically sealed the microcracks and pores, and reduced the filtration loss, so as to greatly improve the stability of shale. The experimental results showed that the synthesized temperature sensitive plugging agent has excellent high‐temperature resistance and plugging performance.

Inhibition of Four Inert Powders on the Minimum Ignition Energy of Sucrose Dust

In order to evaluate the effect of inert powder on the ignition sensitivity of sucrose dust, this study investigated the effects of NaHCO3, NaCl, NH4H2PO4 and Al(OH)3 on the minimum ignition energy (MIE) of sucrose dust. The results showed that all four different inert powders inhibited the MIE of sucrose dust, and all of them showed a trend that the smaller the particle size of the inert powders, the better the inhibition effect. The inhibition effect was ranked as NaHCO3 &gt; NH4H2PO4 &gt; NaCl &gt; Al(OH)3. NaHCO3 and NH4H2PO4 had both physical and chemical inhibition effects, which were better compared to NaCl and Al(OH)3, which had only physical inhibition effects. Analysis of the flame images showed that the inert powder slowed down the combustion of the sucrose dust flame and reduced the flame height. No flame appeared in the region of higher inert powder concentration.

Research on the qualitative and quantitative analysis of the physical and chemical inhibition effect of coal seam inhibitors

The present paper proposes a method for quantitatively identifying the chemical inhibition effect of the inhibitor and aims to reveal the influence of raising the pre-inhibition temperature on chemical inhibition. To be specific, first, the coal samples inhibited with the halogen salt inhibitor and the water-soaked coal samples prepared at different pre-inhibition temperatures were repeated washed with the aid of an ultrasonic cleaner to obtain the inhibited washed coal samples and the reference washed coal samples. Furthermore, the variations of indicator gases, cross-point temperatures and inhibition rates of different coal samples with the rise of pre-inhibition temperature were explored by performing temperature-programmed experiments. Besides, the variations of active groups on the surfaces of the raw and inhibited coal samples were quantitatively analyzed through Fourier transform infrared spectroscopy tests. Based on the above experimental and analysis results, chemical inhibition of the halogen salt inhibitor was preliminarily verified both macroscopically and microscopically, and the respective contribution proportions of physical inhibition and chemical inhibition of the halogen salt inhibitor to the coal seam at different pre-inhibition temperatures were determined. Meanwhile, the influence of pre-inhibition temperature on the inhibitory effect was disclosed. It is concluded that raising the pre-inhibition temperature can promote the contribution proportion of chemical inhibition of the halogen salt inhibitor and significantly reduce the risk of coal self-heating.

Chemical Inhibition of Apurinic-Apyrimidinic Endonuclease 1 Redox and DNA Repair Functions Affects the Inflammatory Response via Different but Overlapping Mechanisms.

The presence of oxidized DNA lesions, such as 7,8-dihydro-8-oxoguanine (8-oxoG) and apurinic/apyrimidinic sites (AP sites), has been described as epigenetic signals that are involved in gene expression control. In mammals, Apurinic-apyrimidinic endonuclease 1/Redox factor-1 (APE1/Ref-1) is the main AP endonuclease of the base excision repair (BER) pathway and is involved in active demethylation processes. In addition, APE1/Ref-1, through its redox function, regulates several transcriptional factors. However, the transcriptional control targets of each APE1 function are not completely known. In this study, a transcriptomic approach was used to investigate the effects of chemical inhibition of APE1/Ref-1 redox or DNA repair functions by E3330 or methoxyamine (MX) in an inflammatory cellular model. Under lipopolysaccharide (LPS) stimulation, both E3330 and MX reduced the expression of some cytokines and chemokines. Interestingly, E3330 treatment reduced cell viability after 48 h of the treatment. Genes related to inflammatory response and mitochondrial processes were downregulated in both treatments. In the E3330 treatment, RNA processing and ribosome biogenesis genes were downregulated, while they were upregulated in the MX treatment. Furthermore, in the E3330 treatment, the cellular stress response was the main upregulated process, while the cellular macromolecule metabolic process was observed in MX-upregulated genes. Nuclear respiratory factor 1 (NRF1) was predicted to be a master regulator of the downregulated genes in both treatments, while the ETS transcription factor ELK1 (ELK1) was predicted to be a master regulator only for E3330 treatment. Decreased expression of ELK1 and its target genes and a reduced 28S/18S ratio were observed, suggesting impaired rRNA processing. In addition, both redox and repair functions can affect the expression of NRF1 and GABPA target genes. The master regulators predicted for upregulated genes were YY1 and FLI1 for the E3330 and MX treatments, respectively. In summary, the chemical inhibition of APE1/Ref-1 affects gene expression regulated mainly by transcriptional factors of the ETS family, showing partial overlap of APE1 redox and DNA repair functions, suggesting that these activities are not entirely independent. This work provides a new perspective on the interaction between APE1 redox and DNA repair activity in inflammatory response modulation and transcription.

Dimethyl Methylphosphonate for the Suppression of Coal Spontaneous Combustion

ABSTRACT The inhibitory effect of dimethyl methylphosphonate (DMMP) on coal spontaneous combustion was investigated. The influence of DMMP on the thermal mass loss and thermal properties in the coal oxidation process was analyzed by synchronous thermal analysis. A DMMP inhibitor concentration of 10% provided the best inhibitory effect on coal oxidation. Addition of DMMP increased the coal ignition temperature by approximately 33°C, the burnout temperature by approximately 63°C, and the initial exothermal temperature by approximately 12°C. It also reduced the total heat release of the coal oxidation process by approximately 1200 J/g. Kinetic analysis of raw coal and DMMP-treated coal showed that DMMP exerted physical inhibition by blocking contact between coal and oxygen in the low-temperature oxidation stage. In the high-temperature oxidation stage, the chemical inhibition effect of DMMP was enhanced and the activation energy increased significantly (approximately 54.79 kJ/mol). Gas phase analysis indicated that DMMP could reduce oxygen consumption and CO emission during the coal oxidation process. On the basis of the above results and quantum chemical analysis, a mechanism for DMMP suppression of coal spontaneous combustion was proposed. This study provides reference data for prevention of coal spontaneous combustion and development of new inhibitors.

Study on the inhibitory property and mechanism of inert powder on dust explosion flame of oil shale

In order to study the inhibitory property and mechanism of inert powder on dust explosion flame in oil shale, five common inert powder and two types of oil shale were selected for the explosion flame inhibition experiment by using the dust explosion flame propagation test system. First, a high-speed camera was used to record the flame image during the inhibition of oil shale dust explosion by inert powder, and the differences in explosion flame length, minimum inerting ratio and flame morphology and structure were analyzed in detail. Then, the thermal decomposition and endothermic characteristics of the inert powder were tested by Thermogravimetric-Differential Scanning Calorimetry (TG-DSC), and the TG-DTG-DSC thermal characteristic curve of the inert powder was analyzed. Combined with the analysis of the inhibition effect of the inert powder in the preheating zone and the combustion flame zone, the inhibitory property and the mechanism of the inert powder on the oil shale dust explosion flame were systematically studied. The research results show that the inhibitory performance of inert powder to the explosion flame of two kinds of oil shale dust is ranked as: ABC dry powder ＞Al(OH)3＞Mg(OH)2＞NaHCO3＞rock powder, and their explosion inhibition performance against Huadian oil shale (HDOS) is better than that of Longkou oil shale (LKOS). In this paper, the physical model of the inhibition mechanism of inert powder on the explosion flame of oil shale dust is established and the inhibition mechanism is analyzed. Through the mechanism analysis, it is shown that the high-efficiency explosive inhibition powder should have good thermal stability (decomposition temperature around 200−400 ℃), high heat absorption, and the decomposition of intermediate products can combine with the combustion reactive radical to play a chemical inhibition effect. The research results can provide theoretical basis and basis for the design of explosion inhibition of oil shale dust and the development of explosive inhibition powder.

The efficiency and toxicity of dodecafluoro-2-methylpentan-3-one in suppressing lithium-ion battery fire

Currently, the effective and clean suppression of lithium-ion battery (LIB) fires remains a challenge. The present work investigates the use of various inhibitor doses (Xin) of dodecafluoro-2-methylpentan-3-one (C6F12O) in 300 Ah LIBs, and systematically examines the thermal and toxic hazards of the extinguished batteries via real scale combustion and gas analysis. The inhibitor is shown to be completely effective. The inhibition mechanism involves a combination of chemical inhibition and physical cooling. While the chemical inhibition effect tends to saturate with increasing Xin, the physical cooling remains effective at higher inhibitor doses. However, extinguishing the battery fire with a high Xin of C6F12O is found to incur serious toxicity problems. These results are expected to provide a guideline for the design of inhibitor doses for the suppression of LIB fires.

Synergistic inhibition of aluminum dust explosion by gas–solid inhibitors

The inhibition mechanism of gas-solid inhibitors on Al dust explosion was investigated experimentally in a closed cuboid chamber. The variation of parameters concerning flame propagation characteristic and explosion severity used to reflect the synergistic inhibition effect of gas-solid inhibitors on Al dust explosion were elucidated. The results showed that flame propagation velocity and explosion overpressure were inhibited with the increase of gas-solid inhibitors. The inhibition curves of gas-solid inhibitors within the experimental range were further obtained. The reason concerning the SEEP phenomenon was revealed through the GC-MS analysis. The combustion of ammonia enhanced the explosion overpressure when solid inhibitors performed at low concentration. The gas-phase product could be regarded as the inert gas as long as enough amount of inhibitors were added. To comprehend the inhibition mechanism of gas-solid inhibitors, X-ray diffraction was applied to figure out the crystal structure of explosion residue. The results indicated that both physical and chemical inhibition effects were imposed on Al dust explosion by gas-solid inhibitors, including endothermic decomposition, dilution of oxidizer, coverage of Al dust, and scavenger of free radicals. The results of this study will provide a scientific basis for the design of inhibition technology for the dust explosion.

Functionalized graphene oxide: Carrier for corrosion inhibitor and barrier in waterborne epoxy coatings

The physical barrier network in polymer matrix composites can be formed by well-dispersed graphene layers, which efficiently inhibited the diffusion of corrosive molecules and improved the corrosion protection properties of the composite coatings. In this work, hydroxyethylidene-1, 1-diphosphonic acid (HEDP) was carried by graphene oxide (GO) layers through covalent bonding and dispersed in waterborne epoxy matrix, aiming for the combined effects of chemical inhibition and physical barrier. Epoxy monomer, ethylene glycol diglycidyl ether (EGDE), was grafted on GO surfaces before the reaction between GO and HEDP in order to prevent the multiple-linkage of graphene layers by HEDP, while improving the compatibility between graphene fillers and the epoxy matrix. The interlayer spacing between GO layers was enlarged from 0.79 nm to 1.03 nm by the reaction with EGDE. The impedance modulus of the composite coatings was kept above 1.5 × 109 Ω cm2 for five months by adding 0.5 wt% graphene derivatives.