IGNITION AND COMBUSTION OF SINGLE SOLID PARTICLES AS NON-ISOTHERMAL METHODS OF CHEMICAL KINETICS

The ignition and combustion of single particles of crystalline boron continue to produce major scientific interest due to the particularities of the process and diversity of potential applications of boron compounds. The full valorization of boron energetic potential is a very current scientific challenge. The objective of the paper is to systematize the methodology for evaluating the kinetic parameters of boron ignition and combustion reactions in various oxidizing gaseous environments. Experimental dependencies between the ignition temperature and the particle size, as well as the combustion time as a function of oxidizing temperature are used for the calculation of the kinetic constants. As a main result, the kinetic parameters of the ignition and combustion reactions of boron in oxygen and water vapor are calculated.

Friedel-Crafts alkylation modification and hydrophilic soft finishing of meta aramid

Based on the Friedel-Crafts alkylation reaction, epichlorohydrin is applied to decorate the meta aramid to enhance the comfort of the fabrics. It is obviously more perfect that the samples are treated with the hydrophilic soft finishing agent. In this paper, the effects of modification and finishing time on the structure and properties of meta aramid are studied. The results indicate that the surface roughness, polarity, active point, and wetting property of the modified fabrics are increased, and the loading rate and fastness of the finishing agent on the meta aramid are enhanced. After finishing, the wetting time and the time of water transfer from the surface to the bottom become shorter in the fabrics, and the water absorption rate becomes faster, the core absorption height rises by 60%, the bending stiffness lowers by 39%, the moisture permeability increases by 5.9%, the permeability decreases by 3.6%, and the friction electric voltage reduces by 78%, The longitudinal and weft secondary combustion time increase by 0.3 s and 0.2 s, the smoldering time increase by 0.3 s, and the improving rate of damage length are 5.4% and 7.6%, respectively.

Experimental Investigation of Effects of Graphene Nano Particles (GNP) on the Combustion Behaviors of Renewable Jet Fuel Droplets

Due to the impact of fossil fuel use on the environment, renewable jet fuel has been pursued as an alternative fuel for aircraft engines. Several renewable jet fuels are developed with minimal carbon footprint and pollutants emission to replace petroleum jet fuels. To modify certain combustion behaviors such as combustion rate, ignition delay and total combustion time, colloidal suspension of carbon-based nanoparticles to liquid fuels has proven to be an effective mechanism. But the influence of carbon-based nanoparticles on the combustion behaviors of renewable jet fuels at different concentrations has not yet been investigated. Researchers have been exploring ways to modify the combustion performances of renewable jet fuel, and in this work, the addition of carbon-based nanoparticles (Graphene Nano Particles) is examined as a potential performance enhancing additive for fuel transport safety. The effects of Graphene Nano Particles (GNP) on the ignition and combustion characteristics of soy oil and canola oil based renewable jet fuel at different mass concentrations (1%, 2% & 3%) loading are investigated in this manuscript. The impact of different mass concentrations loading of GNP on the combustion behavior is analyzed by post-processing the high-speed images. It is observed that the ignition delay decreased by 8.52% and combustion rate decreased by 7.26% for renewable jet fuel at 3% GNP loading. GNP also caused a maximum decrease of total combustion time by 13.61% at 3% loading. It is expected that this study will drive further interest in fuel characteristics improvement of renewable jet fuel and will provide experimental data for future computational modeling.

Modern Regulatory Requirements for Gas Fire Extinguishing to Improve the Safety of Facilities

To implement the technical regulations of the Eurasian Economic Union «On the requirements for fire safety and fire extinguishing equipment» (TR EAEU 043/2017), modern regulatory requirements were developed based on the advanced domestic and foreign research in order to increase the efficiency of using automatic gas fire extinguishing installations. The domestic methodology of experimental determination of the gas extinguishing concentration in the fire chamber has a number of advantages in comparison with the foreign analogues. It is established that it is necessary to take into account the conditions of fire experience for the selection of equipment for a fire extinguishing installation with FK-5-1-12 in the process of its design, in order to ensure more complete evaporation of the liquid phase of FK-5-1-12 after leaving the nozzles. An assumption was substantiated that allows setting the normative concentration of fire extinguishing gases at the level of heptane without conducting a fire experiment to extinguish fires of flammable liquids with a flash point of more than 61 оC. In this case, the concentration value can be taken 15 % less than according to the requirements of ISO 12854: 2009. Experimental studies on extinguishing smoldering materials with gases were conducted. It was established that nitrogen, CO2, freons 114B2 and 227ea at a concentration for extinguishing heptane eliminate not only flame combustion, but also smoldering if the free combustion time does not exceed 3 min. With free combustion for more than 6 minutes, reliable suppression of smoldering is achieved when the oxygen content in the volume of the fire chamber is up to 2.5 % vol. The results of the experiments were taken into account in the draft norms for the design of fire extinguishing installations. Additional requirements were developed for gas fire extinguishing containers and selector valves, which will make it possible to exclude the use of low-quality or obsolete products as part of gas fire extinguishing installations in the territory of the Eurasian Economic Union. The developed modern requirements are included in the drafts of new regulatory documents, which were publicly discussed, and are at the approval stage.

Pengaruh Tekanan Udara Terhadap Temperatur Pembakaran Oli Bekas pada Kompor

Used oil is a waste, and optimization is needed to use it as a fuel properly. In the combustion of used oil, air pressure is very influential in achieving optimal temperature. The air pressure affects the pressure of the incoming air. Other than temperature, air pressure affects and determines the inflow air density. The research uses an experimental method. This study concludes that air pressure affects the temperature of used oil combustion. The higher the air pressure, the more optimum the combustion temperature. A pressure of 2.5 bar yields in maximum temperature of 994.5 ℃ and a combustion time of 151 seconds. Conversely, air pressure of 0.5 bar yields in maximum temperature of 662.0 ℃ and longer combustion time, which is 843 seconds.Oli bekas merupakan limbah, dimana belum terlalu optimal untuk di jadikan bahan bakar. Pada pembakaran oli bekas tekanan udara sangat berpengaruh untuk mencapai temperatur yang optimal. Hal ini berpengaruh pada tekanan udara yang masuk.. Di mana tekanan udara merupakan salah satu faktor yang mempengaruhi dan menentukan kerapatan udara selain daripada suhu. Metode Penelitian yang berkaitan dengan pengaruh tekanan udara terhadap temperatur pembakaran oli bekas pada kompor gas ini menggunakan metode eksperimen. Penelitian ini dapat di simpulkan bahwa tekanan udara berpengaruh pada temperatur pembakaran oli bekas. Pengaruh tekanan udara terhadap temperatur pembakaran yaitu apabila tekanan udara semakin tinggi maka temperatur pembakaran yang di hasilkan lebih maksimal dengan tekanan 2,5 bar mendapatkan 994,5 dan pembakaran semakin cepat yaitu mencatatkan waktu 151 detik, sebaliknya tekanan semakin rendah maka temperatur pembakaran minimal dengan 0,5 bar mendapatkan temperatur 662,0 dan memperoleh waktu pembakaran yang lebih lama yaitu sebesar 843 detik.

Analysis of Combustion Time Based on Atmospheric Temperature Variations of a Gas Turbine Engine

In this study, the combustion instability of a gas turbine engine and the associated combustion delay time were analyzed on the basis of atmospheric temperature variations. A power generating device for combat equipment, which is currently being used in the military, was employed as the gas turbine engine. One of the primary functions of combat equipment is to fully demonstrate maneuverability, and the role and importance of power generating devices for ensuring such maneuverability has always been emphasized on. Additionally, to secure the reliability of the power generation device’s starting performance, it is necessary to stabilize various parameters such as the initial starting stability of the engine, the operation rate, and the output power. Owing to the combustion instability caused by seasonal temperature variations, the gas turbine engine employed in this study is one of the important problematic factors affecting engine performance, durability, and operation. Consequently, in several cases, normal operation and usage of the engine were restricted owing to repeated cases. Hence, in this study, the maneuverability and reliability of the equipment were improved by analyzing the changes in combustion time based on atmospheric temperature variations. Furthermore, the operational environment of the equipment is also summarized in this study.

Warm Needling Treatment in Korea: A Literature Review

Although there have been studies investigating the clinical effects of warm needling (WN) for specific diseases, a comprehensive review of WN is needed. Four Korean internet databases were used in the review of WN treatment performed in Korea. The search terms used to retrieve articles were “warm needling (in Korean; 온침),” “warm acupuncture,” and “warm needle.” A total of 29 articles were reviewed. The following aspects of WN were investigated: language and terminology, study design, use of Standards for Reporting Interventions in Clinical Trials of Acupuncture, research ethics, moxibustion types, number of moxa used, moxa combustion time, needle retention time, treatment time and frequency, acupoints, meridians, acupuncture size and depth, disease classification, pattern identification, outcome measures, and adverse effect. More sophisticated and precise studies on WN are required.

Treatment of medical solid waste using an Air Flow controlled incinerator

In this study, air flow controlled incinerator (AFCI) was used to treat medical solid waste in Vietnam. The experiment was conducted with solid waste samples that was weighed approximately 2.1–3.3 kg/h and had moisture content of 2.8–11.7%. The results showed that an increase in the airflow rate during the drying process accelerated the combustion time by 10–20%, and the optimal airflow rate was 1.1 m/s. The combustion time varied from 0–45 min. The highest temperatures recorded in the drying chamber, carbonisation chamber and combustion chamber after 25–35 min of operation were varied from 195°C, 775°C and 1275°C, respectively. The temperature of the stack was from 33–68°C after the treatment by the wet scrubber using 20% NaOH solution. The combustion capacity was 77.3–87.5%. The experimental results revealed the AFCI process advantages including low operation cost and suitability for treating hazardous waste on a small scale.