A Numerical Study on the Performance of the H2 Shaft Furnace with Dual-Row Top Gas Recycling

Given the urgent pursuit of carbon neutrality and stringent climate policies, the H2 shaft furnace (H2-SF) is starting to gain widespread attention in the steel industry. In this study, the performance of the H2-SF under operation with a dual-row injection top gas recycling system was investigated by a one-dimensional mathematical model. The potential of microwave heating as a means to supply thermal energy in regions of energy deficit was also assessed briefly. The results showed that for scenarios without microwave heating, increasing the upper-row injection rate can improve the furnace performance, and increasing the distance of the upper-row injection level from the furnace top also has a positive effect. A high microwave heating efficiency is expected in regions above the upper-row injection level. For scenarios with microwave heating, a higher microwave power leads to a better furnace performance. Thus, a higher furnace productivity can be achieved by increasing either the upper-row injection rate or the microwave power. However, the latter seems more promising as it decreases the total energy demand due to a better utilization of thermal energy. Based on the comparison of two representative examples, the decrease in the total energy demand is about 0.2 GJ/t-Fe.

Мощность насыщения оптического усилителя на основе самоорганизующихся квантовых точек

Gain saturation in a semiconductor optical amplifier with an array of quantum dots was studied analytically and by numerical simulation on the basis of an analysis of the rate equations. It is shown that, at a moderate injection level, the saturation power increases in proportion to the current density, and then reaches its maximum value, limited by the rate of capture of charge carriers to the ground state and by the number of quantum dots interacting with photons. Expressions are proposed that allow an explicit description of the dependence of the saturation power on the current and its relationship with the internal parameters of the active region.

Recombination Parameters of the Diffusion Region and Depletion Region for Crystalline Silicon Solar Cells under Different Injection Levels

In order to maximize performance in all conditions of use, and to model exactly the performance of solar cells, it is very important to study the recombination parameters under different injection levels. In this paper, the recombination parameters and their effect on the output performance of solar cells are investigated under different injection levels for the full-area aluminum back surface field (Al-BSF) solar cell and passivated emitter and rear cell (PERC) solar cell for the first time. It is found that the recombination parameter J01 of the diffusion region and the recombination parameter J02 of the depletion region for the PERC solar cell are smaller than those of the Al-BSF solar cell under the same injection level. A new finding is that the recombination parameter J01 of Al-BSF solar cells increases quickly with the decreasing injection level compared with PERC solar cells. Finally, the J01/J02 of Al-BSF and PERC solar cells is investigated, and the effects of J01/J02 on the electrical parameters are also analyzed for Al-BSF and PERC solar cells under different injection levels. The obtained conclusions not only clarify the relationship between the recombination parameters and injection levels, but also help to improve cell processes and accurately model daily energy production.

DEPTH ASSESSMENT USING CONTRALATERAL OBLIQUE VIEW DURING CERVICAL INTERLAMINAR EPIDURAL STEROID INJECTIONS

Background: Recent literature has demonstrated that the contralateral oblique (CLO) view provides a more reliable angle in determining needle depth when compared to the lateral view during cervical interlaminar injections. Despite the utilization of CLO safety views, contrast patterns, and loss-of-resistance techniques, inherent risk of injury still remains. Additional safety measures must be assessed to provide clinicians with further safeguards to prevent procedural complications. Objective: The purpose of our study is to provide a reliable method of gauging needle depth insertion during cervical interlaminar injections by comparing the distance from the skin to the epidural space when measured on magnetic resonance imaging (MRI) and when measured intraoperatively. Methods: The study sample included 45 patients with cervical radiculopathy or cervical spinal stenosis. The distance from the skin to the epidural space was measured on cervical spine MRI and with the spinal needle intraoperatively. Primary analysis included the correlation between these distances, and whether differences in depth were influenced by injection level, needle tip location, or body mass index (BMI). Results: A significant correlation (r = .975, P < .001) with an average difference of .03 mm (standard deviation, 2.99 mm) was found between MRI and procedural measurements. Neither injection level nor BMI had a significant influence on the difference in depth. Conclusion: When combined with traditional safety techniques, obtaining preprocedural MRI depth measurements can provide a reliable method in predicting the true needle depth to safely enter the epidural space. Because the majority of patients undergoing interlaminar cervical epidural steroid injections will have already obtained MRI, measuring the distance preprocedurally is a simple and practical method for physicians to implement. Key words: Cervical, fluoroscopy, radiculopathy, injection, contra-lateral oblique, contrast, safety, complications, spinal stenosis, radiation, interlaminar

Comparative Study of 4-Compartmental PK-PD Model with Effective Site Compartment for Different Parameter Set

Target-controlled infusion pumps are for patients to control pain or to infuse sedations and anesthesia, typically those who underwent surgery. The pump has a programmable syringe device used to control the injection level of drugs. These pumps are even used in the ICU or operating theaters to manage patient's pain after surgery or sedation. PK-PD Models are used to obtain the drug concentrations levels of the patient. The model depends on the drug flow rates in different parts of the body. There are many parameter sets available to measure the amount of drugs in the patients. This article presents a three compartmental patient model through Simulink to obtain concentrations levels from different parts of the body. The model is checked for a seven parameter set and suggests the set with the best results.