Rapid and high-capacity MgO composites by salt-controllable precipitation for pre- combustion CO2 capture

Pre-combustion CO2 capture at intermediate temperatures can allow for more flexibility to control over CO2 emission in various industrial processes. For example, the pre-combustion capture can be applied for an Integrated Gasification Combined Cycle (IGCC) due to the use of relatively mild operating temperatures and accessible heat sources. Efficient materials for CO2 capture and H2 production in water gas shift reactor can contribute to improving the overall reliability and efficiency in IGCC process. As a first step, we presented triple salt-promoted MgO composites (NaNaLi salts) by a precipitation method to enhance sorption capacity, rate, and stability. In the conventional precipitation method, a filtration step makes control and reproductivity of the salt composition difficult owing to the unknown residual salts. In this study, we developed a synthesis procedure of precipitation method to control the composition of salts as well as improve physical properties. As-prepared MgO exhibited excellent sorption capacities of 73.0 wt.% at 325 °C in pure CO2 and high sorption rate within 10 min. Stability of composites were evaluated under various gas and time condition and were superior to those of the other MgO-based sorbents reported. With a wet gas mixture (29% CO2, 3% H2O, and balance N2) for sorption and CO2 regeneration, the working capacity stabilized after 20 cycles at 23 and 4.6 wt% for 60/15 min and 10/5 min cycles, respectively. The enhancement and reduction of working capacity along cycles were explained based on liquid phase sintering, i.e., rearrangement, solid-reprecipitation, and densification. However, too long sorption time in the capacity evaluation is not practical because a fixed bed or fluidized bed has a difficulty of temperature control and a large bed size to control high volumes of gases. Therefore, further development is required for an advanced sorbent with high sorption rate and capacity in practical utilization. Therefore, as a second step, a facile method for sorbent with rapid and high-capacity CO2 capture was developed by incorporating additional metal ioninto salt-promoted MgO sorbents using a coprecipitation. At the same fast cycle (10min/5min), the cyclic sorption capacity of 12 wt.% was observed from the developed MgO composite by using wet mixture sorption (29 vol.% CO2, vol.% H2O and N2 balance) and CO2 regeneration. Please click Additional Files below to see the full abstract

Cutaneous Schwannoma Presented as a Pedunculated Protruding Mass

Schwannoma is a benign neoplasm of the nerve sheath origin. It arises from the nerve sheath of large peripheral or cranial nerves and occurs at the level of the subcutaneous fat layer or deeper layer. Cutaneous schwannoma occurs more superficially and usually presents as a solitary dermal or subcutaneous nodule. We describe a case of cutaneous schwannoma that presented as an erythematous pedunculated protruding mass on the left flank of a 19-year-old female. It was clinically diagnosed as a granuloma pyogenicum. Shaving biopsy was conducted and histological examination revealed an encapsulated tumor mass containing dense, spindle-shaped cells whose nuclei are arranged back to back representing Verocay body, and a diagnosis of schwannoma was made. This is an unusual case of cutaneous schwannoma that presented as a pedunculated protruding mass

Development and evaluation of a plant-based air filter system for bacterial growth control

We investigated a novel plant-based air filter system for bacterial growth control. The volatile components released from the experimental plant (Cupressus macrocarpa) were used as the basis of the bacterial growth control and inhibition. We monitored the effect of light on the gas exhausted from the system, and we found that the presence of light induced an increase in the O2 concentration and a decrease in the CO2 concentration in the exhaust gas. A variety of Gram-positive and -negative bacteria was used to elucidate the effect of the exhaust gas on bacterial growth. In the Bacillus subtilis cultivation aerated with the exhaust gas (batch mode), we observed a decrease in the specific growth rate (μ = 0.227 h-1) compared with the control experiments (0.257 h-1). The same result was observed for the Staphylococcus aureus cultivation aerated with the exhaust gas. In the case of Gram-negative bacterial cultivation aerated with the gas, no significant inhibitory effect of the exhaust gas on the bacterial growth was observed. When the number of bacteria (B. subtilis) in a continuous culture was varied at different aeration rates (between 50 to 200 mL/min) using the exhaust gas, a prominent inhibitory effect was observed. Preliminary gas analysis showed that the major inhibitory factors in the exhaust gas are α- and β-pinene and linalool. The results show that the air filter system used in this study could be applied not only as a methodological aspect for estimating antibacterial activity but also for bacteria control in a given system.Keywords: Plant-based biofilter, Cupressus macrocarpa, Bacillus subtilis, Staphylococcus aureus, α-pinene, β-pineneAfrican Journal of Biotechnology Vol. 12(16), pp. 2027-203

Pak2 regulates hematopoietic progenitor cell proliferation, survival and differentiation

p21-Activated kinase 2 (Pak2), a serine/threonine kinase, has been previously shown to be essential for hematopoietic stem cell (HSC) engraftment. However, Pak2 modulation of long-term hematopoiesis and lineage commitment remain unreported. Using a conditional Pak2 knockout mouse model, we found that disruption of Pak2 in HSCs induced profound leukopenia and a mild macrocytic anemia. Although loss of Pak2 in HSCs leads to less efficient short- and long-term competitive hematopoiesis than wild-type cells, it does not affect HSC self-renewal per se. Pak2 disruption decreased the survival and proliferation of multicytokine stimulated immature progenitors. Loss of Pak2 skewed lineage differentiation toward granulocytopoiesis and monocytopoiesis in mice as evidenced by (a) a three- to sixfold increase in the percentage of peripheral blood granulocytes and a significant increase in the percentage of granulocyte-monocyte progenitors in mice transplanted with Pak2-disrupted bone marrow (BM); (b)Pak2-disrupted BM and c-kit(+) cells yielded higher numbers of more mature subsets of granulocyte-monocyte colonies and polymorphonuclear neutrophils, respectively, when cultured in the presence of granulocyte-macrophage colony-stimulating factor. Pak2 disruption resulted, respectively, in decreased and increased gene expression of transcription factors JunB and c-Myc, which may suggest underlying mechanisms by which Pak2 regulates granulocyte-monocyte lineage commitment. Furthermore, Pak2 disruption led to (a) higher percentage of CD4(+) CD8(+) double positive T cells and lower percentages of CD4(+) CD8(-) or CD4(-) CD8(+) single positive T cells in thymus and (b) decreased numbers of mature B cells and increased numbers of Pre-Pro B cells in BM, suggesting defects in lymphopoiesis

LiNLNet: Gauging required nonlinearity in deep neural networks

Feedforward deep neural networks (DNNs) commonly involve layer-wise linear operations and subsequent nonlinear operations, which are repeated through all layers. The nonlinear operations by nonlinear activations in each layer remarkably enhance the expressiveness of DNNs, resulting in the great success in a variety of application domains. Although the necessity of layer-wise nonlinear operations is agreed, the optimal nonlinearity for each layer in a given DNN is not clear. In this regard, we propose an easy-to-use method to layer-wise measure the optimal nonlinearity for a given DNN using its replica termed a linear-nonlinear network (LiNLNet). The key to the LiNLNet is the use of linear-nonlinear units (LiNLUs) whose degree of nonlinearity is parameterized by a trainable parameter p. The parameter p is shared among all LiNLUs in a given layer, thus indicating the layer-wise optimal nonlinearity. This method allows layer-level pruning such that the layers that do not require nonlinearity are merged into the subsequent layers, reducing computational complexity. For proofs of concept, we applied the proposed method to a MLP, AlexNet, VGG16, and ResNet18 on CIFAR-10 and ImageNet. The results commonly indicate the last hidden layer as a linear layer that may be merged into the output layer, reducing memory usage by 27% while maintaining the accuracy for LiNL-AlexNet on ImageNet

Multi-UAV Coverage Path Planning Based on Hexagonal Grid Decomposition in Maritime Search and Rescue

In the event of a maritime accident, surveying the maximum area efficiently in the least amount of time is crucial for rescuing survivors. Increasingly, unmanned aerial vehicles (UAVs) are being used in search and rescue operations. This study proposes a method to generate a search path that covers all generated nodes in the shortest amount of time with multiple heterogeneous UAVs. The proposed model, which is a mixed-integer linear programming (MILP) model based on a hexagonal grid-based decomposition method, was verified through a simulation analysis based on the performance of an actual UAV. This study presents both the optimization technique’s calculation time as a function of the search area size and the various UAV routes derived as the search area grows. The results of this study can have wide-ranging applications for emergency search and rescue operations

Continuous pressure measurement and serial micro-computed tomography analysis during injection laryngoplasty: A preliminary canine cadaveric study.

Injection laryngoplasty (IL) has been used to treat various types of glottal insufficiency. The precise volume and location of the injected materials impact the outcomes. However, exactly how increasing volumes of material are distributed is unknown. In fact, the amount of IL material required to medialize a vocal cord tends to be determined empirically. Thus, the goal of this study was to investigate the pattern of IL material distribution by checking serial micro-computed tomography (MCT) and pressure changes during ILs. This experimental study used 10 excised canine larynges. Experimental devices included the IL syringe, pressure sensor, infusion pump, fixed frame, and monitoring system. We injected calcium hydroxyapatite in the thyroarytenoid muscle; whenever 0.1 mL of material was injected, we obtained an MCT scan while simultaneously measuring the pressure. After the experiments, we performed histologic analyses. MCT analyses showed that materials initially expanded centrifugally and then expanded in all directions within the muscle. The pressure initially increased rapidly but then remained relatively constant until the point at which the materials expanded in multiple directions. Histologic analyses showed that the IL material tended to expand within the epimysium of the thyroarytenoid muscle. However, in some cases, the MCT revealed that there were leakages to the surrounding space with a corresponding pressure drop. If the IL material passes through the epimysium, leakage can occur in the surrounding space, which can account for the reduction in resistance during ILs

A Supercritical CO2 Waste Heat Recovery System Design for a Diesel Generator for Nuclear Power Plant Application

After the Fukushima accident, the importance of an emergency power supply for a nuclear power plant has been emphasized more. In order to maximize the performance of the existing emergency power source in operating nuclear power plants, adding a waste heat recovery system for the emergency power source is suggested for the first time in this study. In order to explore the possibility of the idea, a comparison of six supercritical carbon dioxide (S-CO2) power cycle layouts recovering waste heat from a 7.2 MW alternate alternating current diesel generator (AAC DG) is first presented. The diesel engine can supply two heat sources to the waste heat recovery system: one from exhaust gas and the other from scavenged air. Moreover, a sensitivity study of the cycles for different design parameters is performed, and the thermodynamic performances of the various cycles were evaluated. The main components, including turbomachinery and heat exchangers, are designed with in-house codes which have been validated with experiment data. Based on the designed cycle and components, the bottoming S-CO2 cycle performance under part load operating condition of AAC DG is analyzed by using a quasi-steady state cycle analysis method. It was found that a partial heating cycle has relatively higher net produced work while enjoying the benefit of a simple layout and smaller number of components. This study also revealed that further waste heat can be recovered by adjusting the flow split merging point of the partial heating cycle

Mg-incorporated sorbent for efficient removal of trace CO from H2 gas

Abstract Removal of trace CO impurities is an essential step in the utilization of Hydrogen as a clean energy source. While various solutions are currently employed to address this challenge, there is an urgent need to improve their efficiency. Here, we show that a bead-structured Mg, Cu, and Ce-based sorbent, Mg13CuCeO x , demonstrates superior removal capacity of trace CO from H2 with high stability. The incorporation of Mg boosts sorption performance by enhancing the porous structure and Cu+ surface area. Remarkably, compared to existing pelletized sorbents, Mg13CuCeO x exhibits 15.5 to 50 times greater equilibrium capacity under pressures below 10 Pa CO and 31 times longer breakthrough time in removing 50 ppm CO in H2. Energy-efficient oxidative regeneration using air at 120 °C allows its stable sorption performance over 20 cycles. Through in-situ DRIFTS analysis, we elucidate the reaction mechanism that Mg augments the surface OH groups, promoting the formation of bicarbonate and formate species. This study highlights the potential of MgCuCeO x sorbents in advancing the hydrogen economy by effectively removing trace CO from H2