Exhaust Tube Research Articles

Reductive Thermal ALD of Pd and Pd2Ge From a Novel Recyclable Palladium Chloride Adduct

AbstractIn this work, a new ALD process for palladium metal thin films using dichlorobis(triethylphosphine)palladium(II) (PdCl2(PEt3)2) and 1,4‐bis(trimethylsilyl)‐1,4‐dihydropyrazine ((Me3Si)2DHP) as reactants, is developed. The metal precursor is chosen based on the known reactivity of metal halides with the DHP‐type reducing agents. Metallic Pd films are deposited at temperatures of 140–180 °C with a growth rate of 0.3–0.4 Å cycle−1. Furthermore using 1,4‐bis(trimethylgermyl)‐1,4‐dihydropyrazine ((Me3Ge)2DHP) as the co‐reactant yielded Pd2Ge thin films. Finally, full recyclability of the PdCl2(PEt3)2 is observed: unused molecules condensed in the exhaust tube can be collected by dissolving them into acetone, purified by recrystallization, and reused.

Utilization and Experimental Use of Stainless Steel Metal Scrap Machinery Waste, St-40 Iron, Copper and Aluminum to Reduce Co, Hc, Co2 Elements in Vehicle Exhaust

Air pollution due to motor vehicle exhaust emissions is increased. Polluted air harms human health dan the environment. Consequently, it is essential to make a sustained effort to reduce air pollution. The purpose of this research is to investigate the effect of adding aluminum scrap to the exhaust system of a motor vehicle on gas emissions composition. The motor vehicle exhaust system was modified to accommodate aluminum scrap placement. A gas analyzer was utilized to observe exhaust gas composition, such as carbon dioxide, hydrocarbon, and carbon monoxide. Aluminum scrap with different masses was wrapped around the exhaust's inner tube in 50 gr, 70 gr and 90 gr. The engine speed was maintained at 500 rpm throughout the testing process. It was found that the temperature of the outer exhaust tube is in a range of 40 degrees Celsius to 50 degrees Celsius. The results revealed that the most appropriate amount of aluminum scrap was 90 gr n to reduce carbon monoxide, hydrocarbon, and carbon dioxide in an exhausts gas. The surprising outcome was 76.78 % of carbon monoxide content declined, and furthermore hydrocarbon, and carbon dioxide content were deteriorated by 61.63% and 78.37%, respectively.

Performance of Spouted bed on drying of Foliar fertilizer: Analysis of yield and powder retention

Foliar fertilization is one of the most important management techniques used to improve crop productivity and quality. To increase the efficiency of fertilization, the fertilizer must be highly soluble. The drying of paste and solutions in spouted bed can change the powder structure, making it more soluble. However, depending on the operational conditions, the powder yield produced in this operation may be low. As such, the goal of this research was to investigate the impact of operational conditions on powder yield and powder losses caused by adhesion on the walls of the bed and cyclone, on the particle surface, on the exhaust tube, filter, and filter overflow. To accomplish this, a 23 factorial design was used. The results of powder yield (between 2.3 and 26.6%.) were like those obtained in other spouted bed applications, but lower when compared to spray-dryer. The higher powder retention occurred on the surface of the inert particles and at the bed wall. A high level of instability was observed during spouting, which may have increased the powder adherence at the equipment's walls. The powder obtained after drying was solubilized about 5.9 times fast than the original fertilizer, demonstrating that the technique is promising if the bed stability is maintained.

Minimally invasive surgery versus laparotomy of nonmetastatic pT4a colorectal cancer: a propensity score analysis.

The aim was to compare short-term and long-term oncological outcomes between minimally invasive surgery (MIS group) and laparotomy (lap group) in nonmetastatic pT4a colorectal cancer (CRC). The study retrospectively analyzed the outcomes of 634 patients treated with radical operation from January 2015 to December 2021 for nonmetastatic pT4a CRC, with propensity score matching. The conversion rate from the MIS group to laparotomy is 3.5%. Intraoperative blood loss, time to first anal exhaust, defecation and drainage tube removal, and complication rate were significantly less in the MIS group. After 5 years, the outcomes of the MIS group were no inferior to laparotomy outcomes [overall survival (OS): 72.7 vs. 77.8%, P =0.285; disease-free survival (DFS): 72.2 vs. 75.0%, P =0.599]. And multivariate analysis showed that age greater than or equal to 60 years old, lymph node metastasis and the carcinoembryonic antigen levels were independent variables for OS, while lymph node metastasis and CA125 levels were independent variables for DFS. The results of the graph show the relationship between the sum of scores of sex, age, complications, BMI, carcinoembryonic antigen, age, CA125, tumor site, N stage and tumor length diameter and 1-year, 3-year, and 5-year mortality and DFS of patients. Among them, tumor length diameter and N stage are significantly correlated with long-term survival and disease-free of patients. MIS is safe and feasible for nonmetastatic pT4a CRC, with the added benefit of accelerated postoperative recovery. In oncology, MIS did not affect OS and DFS.

In Situ Measurement of NO, NO2, and H2O in Combustion Gases Based on Near/Mid-Infrared Laser Absorption Spectroscopy.

In this study, a strategy was developed for in situ, non-intrusive, and quantitative measurement of the oxides of nitrogen (NO and NO2) to describe emission characteristics in gas turbines. The linear calibration-free wavelength modulation spectroscopy (LCF-WMS) approach combined with the temperature profile-fitting strategy was utilized for trace NO and NO2 concentration detection with broad spectral interference from gaseous water (H2O). Transition lines near 1308 nm, 5238 nm, and 6250 nm were selected to investigate the H2O, NO, and NO2 generated from combustion. Experiments were performed under different equivalence ratios in a combustion exhaust tube, which was heated at 450–700 K, with an effective optical length of 1.57 m. Ultra-low NOx emissions were captured by optical measurements under different equivalence ratios. The mole fractions of H2O were in agreement with the theoretical values calculated using Chemkin. Herein, the uncertainty of the TDLAS measurements and the limitation of improving the relative precision are discussed in detail. The proposed strategy proved to be a promising combustion diagnostic technique for the quantitative measurement of low-absorbance trace NO and NO2 with strong H2O interference in real combustion gases.

Effects of exhaust tube vortex on the in-furnace phenomena in a swirl-stabilized pulverized coal flame

This paper presents an experimental investigation of the effects of the exhaust tube vortex (ETV) on pollutant emissions and carbon burnout performance. The novelty in this study is to improve understanding of combustion behavior with the ETV structure via detailed in-furnace measurements (temperature, gas-phase species concentration, carbon burnout, emissions, and etc.) in a 16-kWth coal-fired furnace. The experiment considered two different swirling flames (co- and counter-swirl) with four air staging positions. A hollow tubular structure such as the ETV structure has been created under the co-swirl condition. The values of NOx emissions are about 430 ppm, but the CO emission is lower and carbon burnout is approximately 2% higher than that of the counter-swirl unstaging condition at the furnace outlet. For the air staging conditions, the air staging position 3 (SL3) maintained the generated ETV structure stronger in the primary combustion zone. The SL3 condition produced the lowest CO emission at about 275 ppm, and a relatively low emission of NOx showed with the highest carbon burnout performance of approximately 94.5% or more. The SL3 condition is the most favorable condition for the synergistic effect of air staging technology on the ETV structure with a low-NOx swirl-stabilized burner.

Vibration prediction and experimental validation of a rotary compressor based on multi-body dynamics

In this study, an equivalent multi-body dynamics model of a rotary compressor for a household air-conditioner is established to predict its vibration responses when eccentric masses on the crankshaft, cyclic gas loads, torque ripple of the motor, connections with rubber washers, and the intake tube and exhaust tube are considered. Practical experiments for measuring the vibration acceleration of the compressor are conducted to validate the reliability and equivalence of the established model. The design of experiments method is employed to determine the optimal counterweights. This study determines the gas loads required to be considered in the counterweight design to attenuate the compressor vibration effectively. In addition, an optimal assembly angle for two counterweights is attained to reduce the compressor vibration.

The experimental study on the performances of the thermoelectric generator unit affected by heat rate of exhaust system

This study examines the effect of heat rate transferring from the exhaust system of motorcycle to the environment on the performance of the Thermoelectric Generator Unit (TGU). This heat rate is changed by attaching thermal insulation material on the outside of the exhaust system and changing the heat absorbing area of the TGU. The TGU consists of 8 thermoelectric generator modules and collects heat energy from the exhaust to produce electricity. It is attached on the custom muffler of the Suzuki Sapphire 125 and tested in the speed range from 20km/h to 50km/h. The results show that this heat rate affects both the temperature and output power generated by the TGU. The reduction of this heat rate reduces the cool side temperature by limiting the warming effect of cooling air and raise the hot side temperature of the TGU by decreasing heat loss. These two effects lead to the increase of the temperature difference between both sides of the TGU and therefore the output power increases. The difference in output power between test cases can reach up to 54%. Moreover, the heat loss at exhaust tube affects both temperature and output power of TGU from low to mid vehicle speed. However, at high speed, this heat loss at the exhaust tube does not considerably affect the output power of the TGU. To summarize, by reducing the heat rate between exhaust system and environment, the TGU can reach its stable working condition faster and produces more output power. Nonetheless, reducing this heat rate too much may lead to the excess of the hot side temperature of TGU, therefore damaging the thermoelectric generator modules and reducing the conversion efficiency of the TGU.

ВТОРИЧНАЯ ПЕРЕРАБОТКА ЛИТЫХ ТРУБНЫХ КАТОДОВ ПРИ ПОЛУЧЕНИИ МЕТАЛЛОПОРОШКОВОЙ КОМПОЗИЦИИ ДЛЯ ГАЗОТЕРМИЧЕСКОГО НАПЫЛЕНИЯ ПОКРЫТИЙ

The paper presents the results of structural studies of metal-powder compositions (MPC) from the VSDP-3 alloy, as well as heat-resistant atmospheric-plasma powder coatings, developed at the FSUE «VIAM». As blanks for sputtering the MPC, standard charge blanks and exhausted resource cast tube cathodes for ion-plasma deposition were used. It was found that MPC obtained by sputtering cathodes and coatings deposited by sputtering these MPC are not inferior in properties to standard MPC and coatings. At the same time, the cost of such MPC and coatings can be 20–40% lower.

Two Poems

Two Poems by Shira Stav [Untitled] We lived on the edge of a poisonous swamp black alligators bathed in it every morning the exhaust tubes clamored and at noon we saw the thick vapor, opaque almost, rising and its molten smell reaching our noses, we could do nothing but breathe. And we clad our skins in long fabrics and we smeared our faces with powder and we stretched our lips into a smile and we called our names as if they weren’t foreign to us too and we delivered our faces in round lines and we traded words as if they were ours and over the luminous tablecloth we squashed bull testicles on our tongue without any wonder and the screenshot of the flickering heart rhythmically ticking, by itself, to itself, was screened in front of us on bright walls dazzling in its black halo, lingering, and only the insulting body kept getting wet when it wasn’t well covered, trembling when it was cold, dripping when hot, stinking when it wasn’t washed, getting fat, crumpling. On the Road And I have already stopped searching turning my head after every bearded man and son so that they take me with them and make me soup I pushed afar every mother, every father I fended off friends and distant brothers, I folded their attentive ears, skipped the expectant benches, asking for no substitutes, I have a home. It wobbles everywhere on poles behind me with a hungry voice implores me to enter it and fold my legs, take off my shoes, and sit down. Translations from the Hebrew By Maayan Eitan POETRY Shira Stav is a scholar of Hebrew literature and a poet, translator, and literary critic. She is a senior lecturer in the Department of Hebrew Literature at Ben-Gurion University of the Negev. She has published two collections of poetry. Stav won the 2009 Bernstein Prize for literary criticism, the 2007 Teva Award for young Hebrew poets, and the 2013 Bernstein Prize for poetry. To read a bio of Maayan Eitan, turn to page 64. PHOTO BY SAMUEL SCRIMSHAW / UNSPLASH, SHIRA STAV / PHOTO BY ELYA LANDAU 74 WLT WINTER 2021 ...

Thermal Activation of Getters in Magnetron Production Technology

In order to develop a scientifically grounded technology for production of porous getters, there appears the necessity to apply highly sensitive methods for determining the activation temperature, which are compatible with the standard magnetron pumping technology. In this study, a complex technique for determining the activation temperature for porous getters is proposed using the experimental scheme simulating the conditions of porous getter activation in accordance with the standard exhaust tube pumping technology. Under the conditions of the simulation of physicochemical processes in the volume of the heated magnetron housing under pumping, the model of the formation of a gas load on the interior pumping equipment is considered. It is shown that, according to the theory of composite chemical reactions, thermal desorption flows are generated by either the theory of consecutive reactions or the theory of parallel-consecutive reactions. The sorption capacity of porous getters is determined from a plot as the time–temperature dependence of the mass yield of composite chemical reactions of interaction between the gas load and the surface and bulk of a getter tablet. A getter tablet’s change in mass is recorded using the microbalance of a vacuum thermogravimetric unit uninterruptedly at the frequency of one measurement a second throughout the entire period of measurements. The sensitivity threshold of the microbalance is 10–5 g and the maximum mass is 5 g. Using the theory of parallel-consecutive reactions, for the first time, the minimum temperature of thermal activation of a porous getter of a Ti–V (30 at %) alloy is determined, which is the main technological parameter when interior pumping equipment is employed. For the nonisothermal part of the standard heat treatment plot, at the heating rate of 10°C/min and the specified vacuum conditions, the minimum activation temperature is 393°C. For estimating the changes in the roughness of the free surface of a getter washer subjected to interior saturation in a hydrogen medium, scanning electron microscopy is used. Cracks and microsized tetragonal single crystals are found, which might be titanium hydrides TiН2. It is established that crack formation has a positive effect on the getter’s sorption activity due to the appearance of new atomically clean surfaces. However, cracking can contribute to the crumbling of the getter tablet. Therefore, the hydrogen gas load is the factor that limits the durability of the getter.

Numerical evaluation of pulverized coal swirling flames and NOx emissions in a coal-fired boiler: Effects of co- and counter-swirling flames and coal injection modes

A numerical evaluation was performed to investigate the effects of swirl arrangement (co-swirling and counter-swirling flows) and coal injection mode (non-, fully-, and partially-premixed with swirling flow) on the flame structure, coal particle uniformity, burnout performance, and nitrogen oxide (NOx) emissions in a 16-kWth coal-fired boiler. The co-swirling flame exhibits a tulip-shaped inner recirculation zone (IRZ), which increases the coal particle residence time: 1.61 s and 1.45 s for co-swirling and counter-swirling flames, respectively. In addition, the high uniformity of coal particles is maintained in all horizontal cross-sections. The total amount of NOx emissions at the boiler outlet are 205.0 and 551.2 ppm (@6% O2) for the co-swirling and counter-swirling flames, respectively; the deNOx efficiency is 62.8%. An exhaust tube vortex (ETV) structure with a tulip-shaped IRZ is observed in the non-premixed swirling flame injection mode; however, the ETV structure is not observed in the other injection modes. The ETV structure enhanced the coal particle uniformity and expanded the reaction zone, consequently reducing the area of the local high-temperature region. Although the non-premixed injection mode has a slightly lower burnout performance than other injection modes, it is determined to be more effective in reducing the total amount of NOx emissions.

Numerical simulation of accidental released hazardous gas dispersion at a methanation plant using GASFLOW-MPI

Power-to-Gas technologies could play an important role in future energy systems, since they make it possible to store surplus electric energy from fluctuating renewable energy sources such as solar and wind. In Power-to-Gas concepts, the first step towards storage is the production of H2 by electrolysis, a possible further step is methanation. The Engler-Bunte-Institute, Fuel Technology at Karlsruhe Institute of Technology is conducting research on catalytic methanation in slurry bubble column reactors, which represent a highly load flexible reactor technology. To obtain experimental data at a semi-industrial scale a methanation pilot plant was built and commissioned. The plant is equipped with various safety valves, which may release the hazardous gases H2, CO and CH4 in the chemical reactor into the environment in the unintended case of overpressure, which may lead to a flammable and/or toxic cloud, threatening the safety of the workers and other humans near the plant. In this work, the safety evaluation of the accidental release in the methanation plant is performed using the numerical tool GASFLOW-MPI. Both toxicity and flammability of the hazardous gas cloud are analyzed and discussed. A local-global two-step simulation strategy, including a local computational model and a global computational model, is employed to calculate the hazardous gas dispersion efficiently and accurately. In the first step, a local detailed computational model with fine mesh is used to calculate the release mass flow through the exhaust tube and the complicated shock waves directly without any further assumption model such as the notional nozzle model. In the second step, a large-scale model with the relatively coarse mesh is chosen to efficiently predict the hazardous gas dispersion around the entire methanation plant. Moreover, the performances of two different types of exhaust pipes are compared and discussed, and the recommended exhaust pipe design is provided. The simulation results show that version B of the exhaust tubes is more recommendable from the viewpoint of safety.

Chemical Behavior of Byproduct Layer in Exhaust Tube Formed by Silicon Carbide Epitaxial Growth in a System Using Chlorides

This study evaluated the chemical behavior of an oily byproduct which was formed in the exhaust tube during the silicon carbide epitaxial growth process using various precursors, such as silanes, chlorosilanes, propane, hydrogen chloride and hydrogen. Most of the precursors were spontaneously emitted from the oily byproduct, when the oily byproduct was kept under a nitrogen gas flow at atmospheric pressure and at room temperature. When the oily byproduct was exposed to 2-5 % chlorine trifluoride gas in ambient nitrogen at room temperature, various gaseous fluorides were produced, accompanying a slight temperature increase.

High-Speed Schlieren and Particle Image Velocimetry of the Exhaust Flow of a Pulse Detonation Combustor

The exhaust flow of a pulse detonation combustor (PDC) is investigated for different operating conditions. The PDC consists of two units: the deflagration to detonation transition section, and the exhaust tube with a straight nozzle. High-speed high-resolution schlieren images visualize the shock dynamics downstream of the nozzle. The flow dynamics during one full PDC cycle is examined via high-speed particle image velocimetry. A well-suited solid tracer particle for supersonic reactive flow is determined in a preliminary study to minimize the PIV measurement error. The investigated operating conditions of the PDC differ in fill fraction, which is the percentage of the tube filled with a reactive mixture. With increasing fill fraction, the flow features grow in size and strength as the propagation velocity of the leading shock increases. The blowdown process of the PDC is characterized by several exhaust and suction phases. An increase in the fill fraction results in a stronger first exhaust phase, whereas the subsequent suction and exhaust phases remain almost unaffected.

Advanced Opacified Fiber-Reinforced Silica-Based Aerogel Composites for Superinsulation of Exhaust Tubing Systems in Semi-Stationary Motors.

Within this study, monolithic three-dimensional silica aerogel (SA) composite parts with super insulating properties are presented. A generic part based on fiber-reinforced (FR) silica aerogel for thermal insulation of the exhaust tubing system—to keep the exhaust gases as hot as possible to improve the efficiency of the catalyst system—was produced via a sol-gel-based molding process in combination with a supercritical drying using scCO2. A thermal conductivity of 16 mW m−1 K−1 was measured via a heat flow meter technique. In this manuscript, we present a full cycle of the material compound design, starting with fundamental material evaluation including aerogel optimization, opacifier influence, and casting process. The obtained generic part in shape of a half-shell for pipe insulation is characterized under real conditions.

Analysis of the combustion of pellets made with three Cameroonian biomass in a domestic pellet stove

In Sub-Saharan houses, the growing demand of fuels calls for the identification of new renewable and local resources such as biomass, suitable for energy production in small-scale stoves. In these countries, the three-stone-fire type is the most common stove and its use usually leads to high gaseous and particulate emissions. In the present study, combustion experiments of pellets made with three Cameroonian biomass in three different proportions were performed in a domestic pellet stove. The gaseous and particulate emissions were measured in derivations of the exhaust tube through appropriate gas analyzers or collecting filter. The CO concentration was measured between 476 and 675 mg/Nm3, depending on the pellets. The Total Suspended Particles (TSP) were measured in the range 130–240 mg/Nm3, depending on the pellets. These gaseous and TSP emissions were much higher than that obtained when burning normalized EN+ pellets in the same pellet stove. The combustion efficiency was evaluated between 68.5 and 80.2%, depending on the pellets, through standard computations. These values were found in the same range as that (78.2%) obtained when burning normalized EN+ pellets in the same domestic pellet stove.

Strategic combustion technology with exhaust tube vortex flame: Combined effect of biomass co-firing and air-staged combustion on combustion characteristics and ash deposition

A 16-kWth coal-fired furnace with a dual swirl burner was constructed to investigate the combustion characteristics with/without an exhaust tube vortex (ETV) flame, the combined effect of ETV flame and air staging on pollutant emissions, and the carbon burnout performance. The without ETV flame was more favorable than those of with ETV flames in terms of NO emission. However, its CO emission was primarily higher than those of with ETV flames. Through the correlation between pollutant emissions and carbon burnout, it was confirmed that the case with ETV flame exhibited higher stability than that without ETV flame. Consequently, the ETV flames have a positive effect on carbon burnout performance at every air staging level. In addition, the effects of woody biomass co-firing ratios with ETV flame were evaluated according to pollutant emissions and combustion characteristics, as well as ash deposition using scanning electron microscopy-energy dispersive spectroscopy. The increase in woody biomass co-firing ratio exhibited a positive effect on the NO and unburned carbon reduction. The air-staged combustion was more favorable than the unstaged combustion in terms of NO reduction and ash deposition. Air-staged combustion technology should be applied to reduce ash deposition at the co-firing ratio of 20% or more.

Engineering of motorcycle exhaust gases to reduce air pollution

Air pollution from motor vehicle exhaust emissions is increasing, so it is necessary to attempt to control its exhaust emissions. Given the dangers of exhaust emissions, efforts need to be made to control and reduce air pollution so that negative impacts on people and the environment can be reduced. One engineering technology as a manifestation of vehicle emission control is engineering and modification of the exhaust gas channel. Engineering and modification are expected to be able to make a tool that will be able and function to reduce the danger of exhaust gases. The researcher will conduct experiments and manufacture of tools and initial testing on one motorized vehicle to see and observe the composition of the exhaust gas produced from the exhaust. The elements to be observed are CO values, HC values, and CO2 values as comparative data. The tool that will be used to observe and see these elements is the Gas Analyzer tool. This tool is one instrument that is useful for measuring the portion and composition of a combined gas. From the results of testing and analysis obtained data on the exhaust emission test with an average engine speed of 500 rpm, and with the temperature of the exhaust tube 40 °C to 45 °C. After testing the standard exhaust model, then testing the engineering exhaust model which added 50 gr, 70 gr, and 90 gr scrap of stainless steel obtained the best conclusion to reduce and reduce the danger of exhaust emissions is engineered exhaust which added 70 g scrap of stainless steel and when compared to a standard exhaust, CO elements dropped to 71.09% and HC elements dropped to 48.26% and CO2 elements dropped to 66.35%.

Development of a simulation model for the automatic optimization of tools for multi‐dimensional tube forming

AbstractThe increasing number of vehicle components and the advancing lightweight construction in manufacturing processes increasingly require a more flexible design of the exhaust tube geometry. The use of process supplementary simulations is necessary, in order to meet these increasing requirements in the future.The aim of this study is the development of a software tool for the simulation of multi‐dimensional tube forming processes by tube bending and tube embossing. Therefore, a graphical user interface was developed to build‐up and simulate the tube forming processes. The required material parameters for the numerical modeling were determined by means of tensile tests. The simulation models were successfully validated by comparing the numerical results with the experimental results. The influence of the workpiece and the forming tools were numerically investigated on the basis of the validated simulation models. Batch‐related tolerances could be identified as a serious source of deviations. Furthermore, experimental forming errors could be numerically reproduced and corrected by modifying the parameter settings. The tool variation increased the process knowledge and provided the basis for a subsequent optimization. The embossing structure could be optimized satisfactorily by specifying user‐defined requirements.