19 research outputs found

    Thermal Stability Analysis of Hydroprocessing Unit

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    Thermal stability is one of the most critical safety issues in the hydroprocessing units. Runaway reactions in the units can lead to catastrophic consequences as the reactors are being operated at high temperature and pressure, and the reactor effluent is a highly explosive mixture which contains hydrogen and hydrocarbons. For example, a fire and explosion due to a runaway reaction in a hydrocracking unit caused one death and forty-six injuries in 1997, in California. While the temperature runaway is the topic which has been studied extensively, most of the studies worked on simple reactions and little focused on the complex reactions such as hydroprocessing reactions. Also, in the studies on the hydroprocessing reactions, a lumping kinetic model was used which is less accurate and requires experiments for each application. In this research, the thermal stability of a naphtha hydrotreater will be analyzed by using a commercial process simulator ProMax where a novel mechanistic kinetic model, Single Event Kinetics has been integrated. Also, a simplified model will be established by using the data provided by ProMax for further analysis. The continuity and energy equations and parametric sensitivity equations will be solved by Matlab based on the methodology presented by Morbidelli and Varma

    NGL-1/LRRC4C Deletion Moderately Suppresses Hippocampal Excitatory Synapse Development and Function in an Input-Independent Manner

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    Netrin-G ligand-1 (NGL-1), also known as LRRC4C, is a postsynaptic densities (PSDs)-95-interacting postsynaptic adhesion molecule that interacts trans-synaptically with presynaptic netrin-G1. NGL-1 and its family member protein NGL-2 are thought to promote excitatory synapse development through largely non-overlapping neuronal pathways. While NGL-2 is critical for excitatory synapse development in specific dendritic segments of neurons in an input-specific manner, whether NGL-1 has similar functions is unclear. Here, we show that Lrrc4c deletion in male mice moderately suppresses excitatory synapse development and function, but surprisingly, does so in an input-independent manner. While NGL-1 is mainly detected in the stratum lacunosum moleculare (SLM) layer of the hippocampus relative to the stratum radiatum (SR) layer, NGL-1 deletion leads to decreases in the number of PSDs in both SLM and SR layers in the ventral hippocampus. In addition, both SLM and SR excitatory synapses display suppressed short-term synaptic plasticity in the ventral hippocampus. These morphological and functional changes are either absent or modest in the dorsal hippocampus. The input-independent synaptic changes induced by Lrrc4c deletion involve abnormal translocation of NGL-2 from the SR to SLM layer. These results suggest that Lrrc4c deletion moderately suppresses hippocampal excitatory synapse development and function in an input-independent manner

    VLSI Implementation of Restricted Coulomb Energy Neural Network with Improved Learning Scheme

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    This paper proposes a restricted coulomb energy neural network (RCE-NN) with an improved learning algorithm and presents the hardware architecture design and VLSI implementation results. The learning algorithm of the existing RCE-NN applies an inefficient radius adjustment, such as learning all neurons at the same radius or reducing the radius excessively in the learning process. Moreover, since the reliability of eliminating unnecessary neurons is estimated without considering the activation region of each neuron, it is inaccurate and leaves unnecessary neurons extant. To overcome this problem, the proposed learning algorithm divides each neuron region in the learning process and measures the reliability with different factors for each region. In addition, it applies a process of gradual radius reduction by a pre-defined reduction rate. In performance evaluations using two datasets, RCE-NN with the proposed learning algorithm showed high recognition accuracy with fewer neurons compared to existing RCE-NNs. The proposed RCE-NN processor was implemented with 197.8K logic gates in 0.535 mm 2 using a 55 nm CMOS process and operated at the clock frequency of 150 MHz

    Moving Object Detection Based on Optical Flow Estimation and a Gaussian Mixture Model for Advanced Driver Assistance Systems

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    Most approaches for moving object detection (MOD) based on computer vision are limited to stationary camera environments. In advanced driver assistance systems (ADAS), however, ego-motion is added to image frames owing to the use of a moving camera. This results in mixed motion in the image frames and makes it difficult to classify target objects and background. In this paper, we propose an efficient MOD algorithm that can cope with moving camera environments. In addition, we present a hardware design and implementation results for the real-time processing of the proposed algorithm. The proposed moving object detector was designed using hardware description language (HDL) and its real-time performance was evaluated using an FPGA based test system. Experimental results demonstrate that our design achieves better detection performance than existing MOD systems. The proposed moving object detector was implemented with 13.2K logic slices, 104 DSP48s, and 163 BRAM and can support real-time processing of 30 fps at an operating frequency of 200 MHz

    Analysis of Water Quality Characteristics in Unit Watersheds in the Hangang Basin with Respect to TMDL Implementation

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    Spatiotemporal water quality tendencies before and after total maximum daily load (TMDL) implementation in the Hangang basin were analyzed to determine the water quality improvement resulting from the TMDL policy. The periodicities of water quality indicators were also analyzed and water quality characteristics corresponding to different unit watershed units were identified in terms of pollution source. Considering five water quality indicators, including biochemical oxygen demand and total phosphorus, it was observed that water quality indicator concentrations were low in the upstream areas of the Bukhangang and Namhangang watersheds. However, they were high between the downstream areas of the Namhangang watershed and the Imjingang watershed and in the Hangang downstream and Jinwicheon watersheds. Additionally, the concentrations of water quality indicators in most of the unit watersheds where TMDL had been implemented decreased after TMDL implementation. However, increasing tendencies in the concentrations of water quality indicators continued to be observed in some of the watershed units in the upstream areas of the Bukhangang and Namhangang watersheds, possibly because these watersheds are affected by nonpoint source pollution owing to rainfall. Therefore, in the future, it would be necessary to implement policies that take these findings into consideration

    NGL-1/LRRC4C Deletion Moderately Suppresses Hippocampal Excitatory Synapse Development and Function in an Input-Independent Manner

    Get PDF
    Netrin-G ligand-1 (NGL-1), also known as LRRC4C, is a postsynaptic densities (PSDs)-95-interacting postsynaptic adhesion molecule that interacts trans-synaptically with presynaptic netrin-G1. NGL-1 and its family member protein NGL-2 are thought to promote excitatory synapse development through largely non-overlapping neuronal pathways. While NGL-2 is critical for excitatory synapse development in specific dendritic segments of neurons in an input-specific manner, whether NGL-1 has similar functions is unclear. Here, we show that Lrrc4c deletion in male mice moderately suppresses excitatory synapse development and function, but surprisingly, does so in an input-independent manner. While NGL-1 is mainly detected in the stratum lacunosum moleculare (SLM) layer of the hippocampus relative to the stratum radiatum (SR) layer, NGL-1 deletion leads to decreases in the number of PSDs in both SLM and SR layers in the ventral hippocampus. In addition, both SLM and SR excitatory synapses display suppressed short-term synaptic plasticity in the ventral hippocampus. These morphological and functional changes are either absent or modest in the dorsal hippocampus. The input-independent synaptic changes induced by Lrrc4c deletion involve abnormal translocation of NGL-2 from the SR to SLM layer. These results suggest that Lrrc4c deletion moderately suppresses hippocampal excitatory synapse development and function in an input-independent manner. Copyright © 2019 Choi, Park, Jung, Kweon, Kim, Lee, Han, Cho, Kim, Sim, Kim, Bae and Kim

    Intracranial Pressure Patterns and Neurological Outcomes in Out-of-Hospital Cardiac Arrest Survivors after Targeted Temperature Management: A Retrospective Observational Study

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    We aimed to investigate intracranial pressure (ICP) changes over time and the neurologic prognosis for out-of-hospital cardiac arrest (OHCA) survivors who received targeted temperature management (TTM). ICP was measured immediately after return of spontaneous circulation (ROSC) (day 1), then at 24 h (day 2), 48 h (day 3), and 72 h (day 4), through connecting a lumbar drain catheter to a manometer or a LiquoGuard machine. Neurological outcomes were determined at 3 months after ROSC, and a poor neurological outcome was defined as Cerebral Performance Category 3–5. Of the 91 patients in this study (males, n = 67, 74%), 51 (56%) had poor neurological outcomes. ICP was significantly higher in the poor outcome group at each time point except day 4. ICP elevation was highest between days 2 and 3 in the good outcome group, and between days 1 and 2 in the poor outcome group. However, there was no difference in total ICP elevation between the poor and good outcome groups (3.0 vs. 3.1; p = 0.476). All OHCA survivors who had received TTM had elevated ICP, regardless of neurologic prognosis. However, the changing pattern of ICP levels differed depending on the neurological outcome

    S. H. Yoon, J. Y. Han, J. Woo, Y. S. Cho, S.-K. Kwon, Y. C. Bae, D. Kim, E. Kim, M.-H. Kim

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    Metabolic diseases affect various organs including the brain. Accumulation or depletion of substrates frequently leads to brain injury and dysfunction. Deficiency of aminopeptidase P1, a cytosolic proline-specific peptidase encoded by the Xpnpep1 gene, causes an inborn error of metabolism (IEM) characterized by peptiduria in humans. We previously reported that knockout of aminopeptidase P1 in mice causes neurodevelopmental disorders and peptiduria. However, little is known about the pathophysiological role of aminopeptidase P1 in the brain. Here, we show that loss of aminopeptidase P1 causes behavioral and neurological deficits in mice. Mice deficient in aminopeptidase P1 (Xpnpep1-/- ) display abnormally enhanced locomotor activities in both the home cage and open-field box. The aminopeptidase P1 deficiency in mice also resulted in severe impairments in novel-object recognition, the Morris water maze task, and contextual, but not cued, fear memory. These behavioral dysfunctions were accompanied by epileptiform electroencephalogram activity and neurodegeneration in the hippocampus. However, mice with a heterozygous mutation for aminopeptidase P1 (Xpnpep1+/- ) exhibited normal behaviors and brain structure. These results suggest that loss of aminopeptidase P1 leads to behavioral, cognitive and neurological deficits. This study may provide insight into new pathogenic mechanisms for brain dysfunction related to IEMs. © 2017 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society11sciescopu
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