A pressure-swing adsorption process, which uses zeolite 13X as an adsorbent to recover and sequester carbon dioxide from mixture gas (nitrogen and carbon dioxide), is investigated through dynamic simulation and optimization. The purpose of this paper is to improve the purity of each component by finding optimal values of decision variables with a given power constraint. Langmuir isotherm parameters are calculated from experimental data of zeolite 13X and a general mathematical model consisting of a set of partial differential and algebraic equations and solved in gPROMS. The method of centered finite differences is adopted for the discretization of the spatial domains, and a reduced space SQP method is used for the optimization. As a result, the optimal conditions at cyclic steady state are obtained.

This work focuses on the optimization of cyclic adsorption processes to improve the performance of CO 2 capture from flue gas, consisting of nitrogen and carbon dioxide. The adopted processes are the PSA (pressure swing adsorption) process and the FVPSA (fractionated vacuum pressure swing adsorption) process, modified from the FVSA (fractionated vacuum swing adsorption) process developed by Air Products and Chemicals, Inc. The system models are currently bench scale and adopt zeolite13X as an adsorbent. The high-temperature PSA is better for high purity of product (CO 2 ), and the high-temperature FVPSA is much better than the normal-temperature PSA processes. The main goal of this study is to improve the purity and recovery of carbon dioxide. The Langmuir isotherm parameters were calculated from experimental data taken at National Energy Technology Laboratory (Siriwardane, R.; NETL, DOE, 2004). Moreover, efficient optimization strategies are essential to compare these processes. To perform optimization work more efficiently, we modified the previous optimization method by Ko et al. (Ind. Eng. Chem. Res. 2003, 42, 339-348) in a manner similar to that by Jiang et al. (AIChE J. 2003, 49, 1140-1157. This allows us to obtain optimization results with more accurate cyclic steady states (CSSs), better convergence, and faster computation. As a result, optimal conditions at CSS are found for these systems.

Background/Aim With the recent increased share of stand‐up electric scooters (e‐scooters), it is common to see people riding e‐scooters on the roads in Korea. The aim of this study was to investigate traumatic injuries to the craniofacial region related to e‐scooter accidents and to determine the role of dentists (especially oral and maxillofacial surgeons) in the evaluation of patients with trauma at the emergency department due to an e‐scooter accident. Materials and Methods This retrospective study investigated the medical records of patients who visited the Gangnam Severance Hospital Emergency Care Center for trauma related to e‐scooter use from January 1, 2017 to March 31, 2020. Medical records were reviewed to determine the injuries sustained to the craniofacial region related to e‐scooter use, including location of the injury (eg, cranium, craniofacial bone, teeth, soft tissue) and the type of trauma (eg, fracture, laceration, abrasion, contusion, concussion). Result A total of 256 patients' medical records were evaluated. Among them, 125 patients (48.8% of all patients) had sustained craniofacial trauma. Laceration (n = 56, 44.8%) was the most common type of craniofacial injury, followed by cerebral concussion (n = 49, 39.2%), dental injury (n = 27, 21.6%), and craniofacial bone fracture (n = 16, 12.8%). Conclusion Dentists should always consider the possibility of brain trauma and perform a complete craniofacial and oral examination when assessing patients after e‐scooter accidents as outlined by the International Association of Dental Traumatology guidelines. Additionally, it is necessary to educate e‐scooter riders about the importance of wearing protective devices, such as helmets, to reduce the risk of injuries to the craniofacial region.