Heat treatment improves dimensional stability of wood, reduces its decay, and darkens its color. However, mechanical properties of wood can deteriorate during the heat treatment. The effect of ...heat-treatment conditions (maximum treatment temperature, heating rate, exposure time at the maximum heat-treatment temperature, and the gas humidity) on the mechanical properties of North American jack pine (
Pinus banksiana
) was studied using thermogravimetric analyzer. This type of study permits the identification of the best treatment conditions which will minimize reduction of mechanical properties of jack pine. The results showed that the degree of change in bending strength, hardness, screw withdrawal strength, and dimensional stability of jack pine during heat treatment depends strongly on the treatment conditions used. Therefore, great care should be taken to select the treatment conditions. Thermogravimetric analysis can be used as a first step for selection.
Semi-dry desulfurization is an efficient means of SO
removal from the effluent gases from electrolysis cells in aluminum smelters. These gases are at low temperature and contain low concentrations of ...SO
, as opposed to thermal power plants. The removal is carried out by injecting powdered alkaline sorbent, hydrated lime (solid particles), into the SO
-containing gas (gas phase) in the presence of humidity. The reaction is controlled by the adsorption of SO
onto the surface of lime. This study involves the mathematical modelling of a lab-scale scrubber using a Lagrangian-Eulerian approach in order to analyze the desulfurization efficiency. The model was validated based on experimental data. A parametric study was carried out to investigate the effects of particle size, sorbent amount, and relative humidity (RH) on the desulfurization efficiency. The results show that the particle size is the most important parameter; as the particle size decreases, the desulfurization efficiency increases. However, using finer particles may increase the process cost. The loss in SO
capture efficiency due to the use of coarser particle size could be compensated by increasing the relative humidity (RH) of the gas, another key parameter of the process.
Undercalcined coke gained interest as raw material for anodes used in aluminum production since it is reported in the literature that anodes produced with this coke might have lower CO2 reactivity in ...the electrolytic cell. For any anode-grade coke, it is important to identify a suitable pitch which will bond well with that coke during baking and yield dense anodes. The wettability of petroleum coke by molten pitch indicates the quality of bonding between them and influences the final anode properties. In this study, the effect of coke crystallinity on its wettability by pitch has been studied using the sessile-drop test. Also, the chemical and physical properties of coke and pitch have been studied using Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM). It was found that the coke physical and chemical properties depend on its calcination temperature and, thereby, greatly affect the wetting properties. The study showed that the wettability of coke by pitch increases with decreasing crystalline length. The presence of porosity, CC bonds, CO, COO, and heteroatoms (O and N) are important factors which control the wetting of coke by pitch.
Carbon anode is one of the key components for the electrolytic production of aluminum. It is mainly composed of calcined petroleum coke, coal tar pitch, and recycled carbon materials. The impurities ...in the raw materials, which are mainly by-products of different industries, influence significantly the quality of anodes. Usually, no well-known mathematical relationship exists between the various physical and chemical properties of raw materials and the final anode properties. In such situations, the artificial neural network (ANN) methods can serve as a useful tool to predict anode properties. In this study, published data have been used to show the proficiency of different artificial neural networks using the MATLAB software. The average error between the predicted and experimental values is around 6 %. The artificial neural network was also used to identify the effect of impurities such as, vanadium, iron, sodium, and sulfur on the CO
2
reactivity of anodes. ANN also showed the effect of pitch percentage and coke porosity on the CO
2
reactivity of anodes. The effect of CO
2
and air reactivities of coke on the CO
2
reactivity of anode was also studied. The predictions were found to be in good agreement with the results of other studies in the literature.
Metallic nanomaterials, especially gold nanoparticles, which have low toxicity and high photothermal conversion efficiency, exhibit promising theranostic applications in biomedical fields. However, ...detailed preclinical studies of these nanomaterials, such as pharmacokinetics, metabolism, long-term stability and toxicity potential should still be performed. Photoacoustic imaging as a novel non-invasive imaging technique provides convenience for studying real-time semiquantitative pharmacokinetic and biodistribution profiles of drugs or probes to determine whether they can reach the target areas and their metabolic pathways. In this article, we prepared chitosan-capped star shaped gold nanoparticles (AuNSs) and used multispectral optoacoustic tomography (MSOT) to visualize AuNSs in the blood vessels, liver, spleen and kidneys in real time. We also compared these results with chitosan-capped rod shaped gold nanoparticles (AuNRs). The results show that both AuNSs and AuNRs experience rapid blood clearance and have fast and long-term accumulation in the liver and spleen (reaching the peak value within 10 min). The pharmacokinetic data of the two gold nanoparticles fitted to the two-compartment model. The important pharmacokinetic parameters were calculated. The results from MSOT were qualitatively validated by inductively coupled plasma mass spectrometery (ICP-MS). Our results demonstrate that MSOT can serve as an effective tool to monitor gold nanoparticles' pharmacokinetics and biodistribution in specific organs.
Multispectral optoacoustic tomography (MSOT) provides a real-time monitoring method to evaluate gold nanoparticles' pharmacokinetics and biodistribution.
The properties of coal tar pitch, which is used as the binder material for carbon anode production, strongly affect the anode properties. Pitches have significant differences in their chemical ...compositions depending on their origin. In this study, four different coal tar pitches and their blends were studied with the aim of understanding the wettability of a calcined petroleum coke by pitch using the sessile-drop test. In this test, contact angle, which is an indication of wettability, is measured. Contact angles decrease with increasing time, and smaller contact angle means better wettability. The chemical properties of pitches and coke were studied using XPS to investigate their interactions and, consequently, the wetting mechanism. The results showed that blending different pitches influences the wettability. The presence of acidic, basic, and heteroatom containing functional groups in pitch might cause acid–base/condensation reactions when they are blended and, thus, influence the wetting behavior of the pitch blend.
The quality of carbon anodes plays an essential role in the production of primary aluminum. The vibro-compaction is one of the most important steps of the anode fabrication process, which affects the ...anode quality. Over and under-compacting results in anodes with high electrical resistivity, poor mechanical and physical properties. Therefore, the compaction conditions should be chosen carefully. A method and a sound analysis software were developed to determine the optimum vibration time using the sound generated by the vibro-compactor during anode compaction. This method was tested with a bench-scale system both in the laboratory and in the plant. It is simple, fast and inexpensive. The effect of anode raw materials (types of coke and pitch) and top-former bellow pressure of the vibro-compactor on the optimum compaction time as well as the effect of compaction time on anode properties were investigated. The results showed that there are three stages of anode formation during vibro-compaction, good quality anodes can be produced by using compaction time around the optimal value, and the utilization of sound analysis reduces the compaction time.
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•Raw materials as well as the mixing and compaction parameters affect the anode quality.•Anodes go through three stages during vibro-compaction.•Utilization of optimum compaction-time will improve the anode properties.•The sound of the vibro-compactor can be used to determine the optimum compaction-time.•The method developed can assure that each anode is compacted using its specific compaction-time.
Prebaked carbon anodes are used in the electrolytic production of aluminum. They are made of petroleum coke, butts, recycled anodes, and coal tar pitch. The anode quality, which depends on the raw ...material quality and the production conditions, has an important impact on the cell performance. Metallic impurities (V, Ni, and Fe) found in cokes and anodes increase the carbon consumption by catalyzing the air and CO2 reactivities. In turn, this increases the production cost, energy consumption, and the emission of greenhouse gases. The current methods for detecting the metallic impurities in carbon are time consuming and require intensive sample preparation, skilled personnel, and costly reagents. In this work, simple, rapid, and effective tools were developed using colorimetric methods.
High concentrations of transition metal impurities (Fe, V, Ni) in coke increase the carbon anode reactivity, thus increasing carbon consumption, cost, and greenhouse gas emissions. Simple and easy‐to‐use tools to measure the concentration of impurities in coke and anodes were developed, enabling the industry to preselect anode raw materials or to blend cokes in order to reach their targets.
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