Search results for: X. Neil Dong

Authors: Rui Wang, Shanfa Tang, Yuanwu Dong, Siyao Wang

Abstract:

A carboxylate Gemini surfactant N, N`-bis (3-chloro-2 -hydroxypropane-N-dodecyl secondary amine) p-phenylenediamine diacetate sodium (GD12-P-12) was synthesized by substitution and ring-opening reaction from p-phenylenediamine, sodium chloroacetate, epichlorohydrin, and dodecylamine. The synthesis conditions were optimized by controlling variables. The structure of GD12-P-12 was characterized by FT-IR and 1H NMR, and its foam performance, interfacial tension, viscosity was evaluated. The results show that the molecular structure of the synthesized product is consistent with that of the target product, the GD12-P-12 can reduce the oil-water interfacial tension to 7.49×10⁻³mN/m (ultra-low interfacial tension level) in 20min. GD12-P-12 surfactant has excellent foam performance, ultra-low interfacial tension, good temperature-resistant viscosity-increasing properties, has good application prospect in foam flooding.

Keywords: gemini surfactant, optimization of synthesis conditions, foam performance, low interfacial tension

Procedia PDF Downloads 93

Authors: Han Ik Park, Jeong Hyeon Seong, Dong Seop Han, Su-Chul Shin, Young Chul Park

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A Spudcan is mounted on the lower leg of the jack-up rig, a device for preventing a rollover of a structure and to support the structure in a stable sea floor. At the time of inserting the surface of the spud can to penetrate when the sand layer is stable and smoothly pulled to the clay layer, and at that time of recovery when uploading the spud can is equipped with a water injection device. In this study, it is significant to optimize the shape of pipelines holes for water injection device and it was set in two kinds of shape, the oval and round. Interpretation of the subject into the site of Gulf of Mexico offshore Wind Turbine Installation Vessels (WTIV)was chosen as a target platform. Using the ANSYS Workbench commercial programs, optimal design was conducted. The results of this study can be applied to the hole-shaped design of various marine structures.

Keywords: kriging method, jack-up rig, shape optimization, spudcan

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Authors: Qifei Jing, Vadim V. Silberschmidt, Lin Li, ZhiLi Dong

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Graphene oxide (GO) was chemically functionalized to prepare polyurethane (PU) composites with improved mechanical and thermal properties. In order to achieve a well exfoliated and stable GO suspension in an organic solvent (dimethylformamide, DMF), 4, 4′- methylenebis(phenyl isocyanate) and polycaprolactone diol, which were the two monomers for synthesizing PU, were selectively used to functionalize GO. The obtained functionalized GO (FGO) could form homogeneous dispersions in DMF solvent and the PU matrix, as well as provide a good compatibility with the PU matrix. The most efficient improvement of mechanical properties was achieved when 0.4 wt% FGO was added into the PU matrix, showing increases in the tensile stress, elongation at break and toughness by 34.2%, 27.6% and 64.5%, respectively, compared with those of PU. Regarding the thermal stability, PU filled with 1 wt% FGO showed the largest extent of improvement with T2% and T50% (the temperatures at which 2% and 50% weight-loss happened) 16 °C and 21 °C higher than those of PU, respectively. The significant improvement in both mechanical properties and thermal stability of FGO/PU composites should be attributed to the homogeneous dispersion of FGO in the PU matrix and strong interfacial interaction between them.

Keywords: composite, dispersion, graphene oxide, polyurethane

Procedia PDF Downloads 227

Authors: Min Kyu Kim, Eun Young Lee, Dong Woo Son, Yoon Seok Chang

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In this paper, we introduce a flexible box erecting machine (BEM) that swiftly and automatically transforms cardboard into a three dimensional box. Recently, the parcel service and home-shopping industries have grown rapidly, and there is an increasing need for various box types to ship various products. However, workers cannot fold thousands of boxes manually in a day. As such, automatic BEMs are garnering greater attention. This study takes equipment operation into consideration as well as mechanical improvements in order to design a BEM that is able to outperform its conventional counterparts. We analyzed six dispatching rules – First In First Out (FIFO), Shortest Processing Time (SPT), Earliest Due Date (EDD), Setup Avoidance, EDD + SPT, and EDD + Setup Avoidance – to determine which one was most suitable for BEM operation. Consequently, SPT and Setup Avoidance were found to be the most critical rules, followed by EDD + Setup Avoidance, EDD + SPT, EDD, and FIFO. This hierarchy was valid for both our conventional BEM and our new flexible BEM from the viewpoint of processing time. We believe that this research can contribute to flexible BEM management, which has the potential to increase productivity and convenience.

Keywords: automation, box erecting machine, dispatching rule, setup time

Procedia PDF Downloads 334

Authors: Zhipeng Dong, Jing Guo

Abstract:

Graphene-semiconductor contacts have been extensively studied recently, both as a stand-alone diode device for potential applications in photodetectors and solar cells, and as a building block to vertical transistors. Graphene is a two-dimensional nanomaterial with vanishing density-of-states at the Dirac point, which differs from conventional metal. In this work, image-charge-induced barrier lowering (BL) in graphene-semiconductor contacts is studied and compared to that in metal Schottky contacts. The results show that despite of being a semimetal with vanishing density-of-states at the Dirac point, the image-charge-induced BL is significant. The BL value can be over 50% of that of metal contacts even in an intrinsic graphene contacted to an organic semiconductor, and it increases as the graphene doping increases. The dependences of the BL on the electric field and semiconductor dielectric constant are examined, and an empirical expression for estimating the image-charge-induced BL in graphene-semiconductor contacts is provided.

Keywords: graphene, semiconductor materials, schottky barrier, image charge, contacts

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Authors: Dong Sik Cho, Yong Kweon Suh

Abstract:

Numerical study has been conducted on the electro-hydrodynamic (EHD) pumping method in terms of a recirculating channel. The method relies on the principle of EHD generated by the electric-field dependent electrical conductivity (Onsager effect). Before considering the full three-dimensional simulation, we solved the two-dimensional problem of EHD flow in a circular channel like a doughnut shape. We observed that when dc voltage was applied a fast and regular flow was produced around electrodes, which is then used as a driving force for the fluid pumping. In this parametric study, the diameters of circular electrodes are varied in the range 0.3mm~3mm and the gap between the electrodes pair is varied in the range 0.3mm~2mm. We found that both the volume flow rate and the pumping efficiency are increased as the distance between the electrodes is decreased. Finally, we also performed the numerical simulation for the three-dimensional channel and found that the averaged flow velocity is in the same order of magnitude as the two-dimensional one.

Keywords: electro-hydrodynamic, electric-field, onsager effect, DC voltage

Procedia PDF Downloads 273

Authors: Hoyoung Lee, Dong-Kyu Kim, Seung-Young Kho, R. Eddie Wilson

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This study quantifies a decrement in freeway capacity during rainfall. Traffic and rainfall data were gathered from Highway Agencies and Wunderground weather service. Three inter-urban freeway sections and its nearest weather stations were selected as experimental sites. Capacity analysis found reductions of maximum and mean pre-breakdown flow rates due to rainfall. The Kruskal-Wallis test also provided some evidence to suggest that the variance in the pre-breakdown flow rate is statistically insignificant. Potential application of this study lies in the operation of real time traffic management schemes such as Variable Speed Limits (VSL), Hard Shoulder Running (HSR), and Ramp Metering System (RMS), where speed or flow limits could be set based on a number of factors, including rainfall events and their intensities.

Keywords: capacity randomness, flow breakdown, freeway capacity, rainfall

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Authors: Young S. Bang, Dong H. Yoon, Seung H. Yoo

Abstract:

Emergency Core Coolant Bypass (ECC Bypass) has been regarded as an important phenomenon to peak cladding temperature of large-break loss-of-coolant-accidents (LBLOCA) in nuclear power plants (NPP). A modeling scheme to address the ECC Bypass phenomena and the calculation of LBLOCA using that scheme are discussed in the present paper. A hydraulic form loss coefficient (HFLC) from the reactor vessel downcomer to the broken cold leg is predicted by the computational fluid dynamics (CFD) code with a variation of the void fraction incoming from the downcomer. The maximum, mean, and minimum values of FLC are derived from the CFD results and are incorporated into the LBLOCA calculation using a system thermal-hydraulic code, MARS-KS. As a relevant parameter addressing the ECC Bypass phenomena, the FLC to the break and its range are proposed.

Keywords: CFD analysis, ECC bypass, hydraulic form loss coefficient, system thermal-hydraulic code

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Authors: Jing Yu, Hongyang Liu, Dong Hao

Abstract:

On-Orbit Refueling is of great significance in extending space crafts' lifetime. The problem of minimum-fuel, time-fixed, Peer-to-Peer On-Orbit Refueling mission planning is addressed here with the particular aim of assigning fuel-insufficient satellites to the fuel-sufficient satellites and optimizing each rendezvous trajectory. Constraints including perturbation, communication link, sun illumination, hold points for different rendezvous phases, and sensor switching are considered. A planning model has established as well as a two-level solution method. The upper level deals with target assignment based on fuel equilibrium criterion, while the lower level solves constrained trajectory optimization using special maneuver strategies. Simulations show that the developed method could effectively resolve the Peer-to-Peer On-Orbit Refueling mission planning problem and deal with complex constraints.

Keywords: mission planning, orbital rendezvous, on-orbit refueling, space mission

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Authors: Hui Wei, Zheng Dong

Abstract:

Object recognition has long been a challenging task in computer vision. Yet the human brain, with the ability to rapidly and accurately recognize visual stimuli, manages this task effortlessly. In the past decades, advances in neuroscience have revealed some neural mechanisms underlying visual processing. In this paper, we present a novel model inspired by the visual pathway in primate brains. This multi-layer neural network model imitates the hierarchical convergent processing mechanism in the visual pathway. We show that local image features generated by this model exhibit robust discrimination and even better generalization ability compared with some existing image descriptors. We also demonstrate the application of this model in an object recognition task on image data sets. The result provides strong support for the potential of this model.

Keywords: biological model, feature extraction, multi-layer neural network, object recognition

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Authors: Ruitao Li, Zhili Dong, Nay Win Khun, Khiam Aik Khor

Abstract:

In this study, microstructure and sintering mechanism as well as wear resistance properties of Ti/Al-Cr-Fe metal matrix composites (MMCs) fabricated by spark plasma sintering (SPS) with Ti as matrix and Al-Cr-Fe as reinforcement were investigated. Phases and microstructure of the sintered samples were analyzed using X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). Wear resistance properties were tested by ball-on-disk method. An Al3Ti ring forms around each Al-Cr-Fe particle as the bonding layer between Ti and Al-Cr-Fe particles. The Al content in Al-Cr-Fe particles experiences a decrease from 70 at.% to 60 at.% in the sintering process. And these particles consist of quasicrystalline icosahedral AlCrFe and quasicrystal approximants γ-brass Al8(Cr,Fe)5 and Al9(Cr,Fe)4 in the sintered compact. The addition of Al-Cr-Fe particles into the Ti matrix can improve the microhardness by about 40% and the wear resistance is improved by more than 50% due to the increase in the microhardness and the change of wear mechanism.

Keywords: metal matrix composites, spark plasma sintering, phase transformation, wear

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Authors: Scott A. Ochsner, Christopher M. Watkins, Apollo McOwiti, David L. Steffen Lauren B. Becnel, Neil J. McKenna

Abstract:

Understanding signaling by nuclear receptors (NRs) requires an appreciation of their cognate ligand- and tissue-specific transcriptomes. While target gene regulation data are abundant in this field, they reside in hundreds of discrete publications in formats refractory to routine query and analysis and, accordingly, their full value to the NR signaling community has not been realized. One of the mandates of the Nuclear Receptor Signaling Atlas (NURSA) is to facilitate access of the community to existing public datasets. Pursuant to this mandate we are developing a freely-accessible community web resource, Transcriptomine, to bring together the sum total of available expression array and RNA-Seq data points generated by the field in a single location. Transcriptomine currently contains over 25,000,000 gene fold change datapoints from over 1200 contrasts relevant to over 100 NRs, ligands and coregulators in over 200 tissues and cell lines. Transcriptomine is designed to accommodate a spectrum of end users ranging from the bench researcher to those with advanced bioinformatic training. Visualization tools allow users to build custom charts to compare and contrast patterns of gene regulation across different tissues and in response to different ligands. Our resource affords an entirely new paradigm for leveraging gene expression data in the NR signaling field, empowering users to query gene fold changes across diverse regulatory molecules, tissues and cell lines, target genes, biological functions and disease associations, and that would otherwise be prohibitive in terms of time and effort. Transcriptomine will be regularly updated with gene lists from future genome-wide expression array and expression-sequencing datasets in the NR signaling field.

Keywords: target gene database, informatics, gene expression, transcriptomics

Procedia PDF Downloads 249

Authors: Adam Y. Sulaiman, Donal F. Cotter, Ming J. Huang, Neil J. Hewitt

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Decarbonization of the industrial sector in developed countries has become indispensable for addressing climate change. Industrial processes including drying, distillation, and injection molding require a process heat exceeding 180°C, rendering the subcriticalHigh-Temperature heat pump(HTHP) technique unsuitable. A transcritical HTHP utilizing ecologically friendly working fluids is a highly recommended system that incorporates the features of high-energy efficiency, extended operational range, and decarbonizing the industrial sector. This paper delves into the possibility and feasibility of leveraging the HTTP system to provide up to 200°C of heat using R1233zd(E) as a working fluid. Using a steady-state model, various transcritical HTHP cycle configurations aretheoretically compared,analyzed, and evaluatedin this study. The heat transfer characteristics for the evaporator and gas cooler are investigated, as well as the cycle's energy, exergetic, and environmental performance. Using the LMTD method, the gas cooler's heat transfer coefficient, overall length, and heat transfer area were calculated. The findings indicate that the heat sink pressure level, as well as the waste heat temperature provided to the evaporator, have a significant impact on overall cycle performance. The investigation revealed the potential challenges and barriers, including the length of the gas cooler and the lubrication of the compression process. The basic transcritical HTTP cycle with additional IHX was demonstrated to be the most efficient cycle across a variety of heat source temperatures ranging from 70 to 90 °C based on theoretical energetic and exergetic performance.

Keywords: high-temperature heat pump, transcritical cycle, refrigerants, gas cooler, energy, exergy

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Authors: Sungkyung Kim, Jee-Hyeon Na, Dong-Seung Kwon

Abstract:

Future mobile networks following 5th generation will be characterized by one thousand times higher gains in capacity; connections for at least one hundred billion devices; user experience capable of extremely low latency and response times. To be close to the capacity requirements and higher reliability, advanced technologies have been studied, such as multiple connectivity, small cell enhancement, heterogeneous networking, and advanced interference and mobility management. This paper is focused on the multiple connectivity in heterogeneous cellular networks. We investigate the performance of coverage and user throughput in several deployment scenarios. Using the stochastic geometry approach, the SINR distributions and the coverage probabilities are derived in case of dual connection. Also, to compare the user throughput enhancement among the deployment scenarios, we calculate the spectral efficiency and discuss our results.

Keywords: heterogeneous networks, multiple connectivity, small cell enhancement, stochastic geometry

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Authors: Adam Y. Sulaiman, Donal F. Cotter, Ming J. Huang, Neil J. Hewitt

Abstract:

Suitable low global warming potential (GWP) refrigerants that conform to F-gas regulations are required to extend the operational envelope of high-temperature heat pumps (HTHPs) used for industrial waste heat recovery processes. The thermophysical properties and characteristics of these working fluids need to be assessed to provide a comprehensive understanding of operational effectiveness in HTHP applications. This paper presents the results of a theoretical simulation to investigate a range of low-GWP refrigerants and their suitability to supersede refrigerants HFC-245fa and HFC-365mfc. A steady-state thermodynamic model of a single-stage HTHP with an internal heat exchanger (IHX) was developed to assess system cycle characteristics at temperature ranges between 50 to 80 °C heat source and 90 to 150 °C heat sink. A practical approach to maximize the operational efficiency was examined to determine the effects of regulating minimum superheat within the process and subsequent influence on energetic and exergetic efficiencies. A comprehensive map of minimum superheat across the HTHP operating variables were used to assess specific tipping points in performance at 30 and 70 K temperature lifts. Based on initial results, the refrigerants HCFO-1233zd(E) and HFO-1336mzz(Z) were found to be closely aligned matches for refrigerants HFC-245fa and HFC-365mfc. The overall results show effective performance for HCFO-1233zd(E) occurs between 5-7 K minimum superheat, and HFO-1336mzz(Z) between 18-21 K dependant on temperature lift. This work provides a method to optimize refrigerant selection based on operational indicators to maximize overall HTHPs system performance.

Keywords: high-temperature heat pump, minimum superheat, energy & exergy efficiency, low GWP refrigerants

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Authors: Kyoungwoo Park, Gil Dong Kim, Seong Joon Moon, Ho Kil Lee

Abstract:

The Urea-SCR is one of the most efficient technologies to reduce NOx emissions in diesel engines. In the present work, the computational prediction of internal flow and spray characteristics in the Urea-SCR system was carried out by using 3D-CFD simulation to evaluate NH3 uniformity index (NH3 UI) and its activation time according to the official New European Driving Cycle (NEDC). The number of nozzle and its diameter, two types of injection directions, and penetration length were chosen as the design variables. The optimal solutions were obtained by coupling the CFD analysis with Taguchi method. The L16 orthogonal array and small-the-better characteristics of the Taguchi method were used, and the optimal values were confirmed to be valid with 95% confidence and 5% significance level through analysis of variance (ANOVA). The results show that the optimal solutions for the NH3 UI and activation time (NH3 UI 0.22) are obtained by 0.41 and 0,125 second, respectively, and their values are improved by 85.0% and 10.7%, respectively, compared with those of the base model.

Keywords: computational fluid dynamics, NH3 uniformity index, optimization, Taguchi method, Urea-SCR system, UWS injector

Procedia PDF Downloads 238

Authors: Ji-Suk Kim, Dong-Pil Kim, Kee-Rae Gang, Yoon Ho Choi

Abstract:

This study was conducted to investigate the characteristics of butterfly communities according to the habitat characteristics of Korean veins. The survey sites were 12 mountains located in the vein, and 12~30 quadrats (200 in total) were set. The species richness and biodiversity were different according to land use type. Two types of land use (forest and graveyard) showed lower species diversity index values ​​than other land use types. The species abundance was low in the forest and graveyards, and grasslands, forest tops, cultivated areas and urban areas showed relatively high species richness. The altitude was not statistically significant with the number of species of butterflies and biodiversity index. The degree of canopy closure showed a negative correlation. As a result of interspecific correlation analysis, it was confirmed that there was a very high correlation (R2=0.746) between Lycaena phlaeas and Pseudozizeeria maha argia, Choaspes benjaminii japonica and Argyronome ruslana.

Keywords: land use type, species diversity index, correlation, canopy closure

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Authors: Tae-min Byun, Chang-soo Chon, Dong-hyun Seo, Han-sung Kim, Bum-mo Ahn, Hui-suk Yun, Cheolwoong Ko

Abstract:

In this study, a 3-point bending computational analysis of normal and osteoporosis mouse models was performed based on the Micro-CT image information of the femurs. The finite element analysis (FEA) found 1.68 N (normal group) and 1.39 N (osteoporosis group) in the average maximum force, and 4.32 N/mm (normal group) and 3.56 N/mm (osteoporosis group) in the average stiffness. In the comparison of the 3-point bending test results, the maximum force and the stiffness were different about 9.4 times in the normal group and about 11.2 times in the osteoporosis group. The difference between the analysis and the test was greatly significant and this result demonstrated improvement points of the material properties applied to the computational analysis of this study. For the next study, the material properties of the mouse femur will be supplemented through additional computational analysis and test.

Keywords: 3-point bending test, mouse, osteoporosis, FEA

Procedia PDF Downloads 323

Authors: Ramuel Spirituel Mattathiah A. San Juan, Neil Ambasing

Abstract:

Background: Reversal of vision metamorphopsia is a transient form of metamorphopsia described as an upside-down alteration of the visual field in the coronal plane. Patients would describe objects, such as cups, upside down, but the tea would not spill, and people would walk on their heads. It is extremely rare as a stable finding, lasting days or weeks. We report a case wherein this type of metamorphopsia occurred only in written words and lasted for six months. Objective: To the best of our knowledge, we report the first rare occurrence of reversal of vision metamorphopsia described as inverted words as the sole initial presentation of an underlying stroke. Case Presentation: We report a 59-year-old male with poorly controlled hypertension and diabetes mellitus who presented with a 3-day history of difficulty reading, described as the words were turned upside down as if the words were inverted horizontally then with the progression of deficits such as right homonymous hemianopia and achromatopsia, prosopagnosia. Cranial magnetic resonance imaging (MRI) revealed an acute infarct on the left posterior cerebral artery territory. Follow-up after six months revealed improvement of the visual field cut but with the persistence of the higher cortical function deficits. Conclusion: We report the first rare occurrence of metamorphopsia described as purely inverted words as the sole initial presentation of an underlying stroke. The differential diagnoses of a patient presenting with text reversal metamorphopsia should include stroke in the occipitotemporal areas. It further expands the landscape of metamorphopsias due to its exclusivity to written words and prolonged duration. Knowing these clinical features will help identify the lesion locus and improve subsequent stroke care, especially in time-bound management like intravenous thrombolysis.

Keywords: rare presentation, text reversal metamorphopsia, ischemic stroke, stroke

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Authors: Ramuel Spirituel Mattathiah A. San Juan, Neil Ambasing

Abstract:

Background: In lateral medullary strokes, hemiparesis doesn't typically manifest due to the distinct vascular supply to the corticospinal tract located within the medulla's tegmentum. Hemiparesis resulting from a medullary infarct would likely be attributable to a medial medullary stroke characterized by contralateral hemiparesis since the corticospinal tract fibers at this level have yet to cross over. This paper reports a unique case of a lateral medullary stroke variant that presented with ipsilateral hemiparesis. Objective: There have only been 23 other cases of reported Opalski syndrome, making this only the 24th and 25th case reported worldwide. Case Presentation: A 53-year-old male was admitted with slurring of speech with gait instability, numbness on the right face, Horner’s syndrome, and 4/5 motor strength on the right extremities. Hyperreflexia was noted on the right, together with a Babinski’s sign. Cranial magnetic resonance imaging (MRI) showed an infarct on the right dorsolateral medulla. A 48-year-old male was admitted complaining of dizziness, ataxic gait, veering to the left during ambulation, left facial numbness, left hemiplegia, crossed sensory disturbance, and right limb ataxia. MRI revealed an acute left lateral medullary infarction. Conclusion: A rare type of lateral medullary infarction, the Opalski Syndrome, is a weakness ipsilateral to the lesion of the infarct. The lesion involves the ipsilateral corticospinal tract below the pyramidal decussation. The considerable diversity in the posterior brain circulation serves as a contributing factor to the clinical observation of incomplete textbook syndromes, underscoring the significance of the neurological clinical approach and a solid foundation in neuroanatomy.

Keywords: Opalski syndrome, rare stroke, stroke, Wallenberg's syndrome

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Authors: R. K. Vinnakota, D. A. Genov, Z. Dong, A. F. Briggs, L. Nordin, S. R. Bank, D. Wasserman

Abstract:

We present a semiconductor-based plasmonic electro-optic modulator based on excitation and active control of surface plasmon polaritons (SPPs) at the interface of degenerately doped In₀.₅₃Ga₀.₄₇As pn++ junctions. Set of devices, which we refer to as a surface plasmon polariton diode (SPPD), are fabricated and characterized electrically and optically. Optical characterization predicts far-field voltage-aided reflectivity modulation for mid-IR wavelengths. Numerical device characterizations using a self-consistent electro-optic multiphysics model have been performed to confirm the experimental findings were predicting data rates up to 1Gbits/s and 3dB bandwidth as high as 2GHz. Our findings also show that decreasing the device dimensions can potentially lead to data rates of more than 50Gbits/s, thus potentially providing a pathway toward fast all-semiconductor-based plasmotronic devices.

Keywords: plasmonics, optoelectronics, PN junctions, surface plasmon polaritons

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Authors: Abdulla Rahil, Rupert Gammon, Neil Brown

Abstract:

The rapid growth of renewable energy sources and their integration into the grid have been motivated by the depletion of fossil fuels and environmental issues. Unfortunately, the grid is unable to cope with the predicted growth of renewable energy which would lead to its instability. To solve this problem, energy storage devices could be used. Electrolytic hydrogen production from an electrolyser is considered a promising option since it is a clean energy source (zero emissions). Choosing flexible operation of an electrolyser (producing hydrogen during the off-peak electricity period and stopping at other times) could bring about many benefits like reducing the cost of hydrogen and helping to balance the electric systems. This paper investigates the price of hydrogen during flexible operation compared with continuous operation, while serving the customer (hydrogen filling station) without interruption. The optimization algorithm is applied to investigate the hydrogen station in both cases (flexible and continuous operation). Three different scenarios are tested to see whether the off-peak electricity price could enhance the reduction of the hydrogen cost. These scenarios are: Standard tariff (1 tier system) during the day (assumed 12 p/kWh) while still satisfying the demand for hydrogen; using off-peak electricity at a lower price (assumed 5 p/kWh) and shutting down the electrolyser at other times; using lower price electricity at off-peak times and high price electricity at other times. This study looks at Derna city, which is located on the coast of the Mediterranean Sea (32° 46′ 0 N, 22° 38′ 0 E) with a high potential for wind resource. Hourly wind speed data which were collected over 24½ years from 1990 to 2014 were in addition to data on hourly radiation and hourly electricity demand collected over a one-year period, together with the petrol station data.

Keywords: hydrogen filling station off-peak electricity, renewable energy, off-peak electricity, electrolytic hydrogen

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Authors: Dong-Woo Kang

Abstract:

This paper presents an optimal magnet shape of a spoke-shaped interior permanent magnet synchronous motor by using ferrite magnets. Generally, the permanent magnet motor used the ferrite magnets has lower output power and efficiency than a rare-earth magnet motor, because the ferrite magnet has lower magnetic energy than the rare-earth magnet. Nevertheless, the ferrite magnet motor is used to many industrial products owing to cost effectiveness. In this paper, the authors propose a high power density design of the ferrite permanent magnet synchronous motor. Furthermore, because the motor design has to be taken a manufacturing process into account, the design is simulated by using the finite element method for analyzing the demagnetization, the magnetizing, and the structure stiffness. Especially, the magnet shape and dimensions are decided for satisfying these properties. Finally, the authors design an optimal motor for applying our system. That final design is manufactured and evaluated from experimentations.

Keywords: demagnetization, design optimization, magnetic analysis, permanent magnet motors

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Authors: Chung-Yang Chuang, Hui-Min Wang, Min-Yan Dong, Chang-Jung Chang

Abstract:

PET fiber is the most widely used fiber worldwide. This man-made fiber is prepared from petroleum chemicals, which may cause environmental pollution and resource exhausting issues, such as the use of non-renewable sources, greenhouse gas emission and discharge of wastewater. Therefore, the textile made by recycle-PET is the trend in the future. Recycle-PET fiber, compared with petroleum-made PET, shows lower carbon emissions and resource exhaustion. However, “fabric decoloring” is the key barrier to textile recycling. The dyes existing in the fabrics may cause PET chain degradation and appearance drawbacks during the textile recycling process. In this research, the water-based decoloring agent was used to remove the dispersed dye in the PET fabrics in order to obtain the colorless PET fabrics after the decoloring process. The decoloring rate of PET fabrics after the decoloring process was up to 99.0%. This research provides a better solution to resolve the issues of appearance and physical properties degradation of fabrics-recycle PET materials due to the residual dye. It may be possible to convert waste PET textiles into new high-quality PET fiber and build up the loop of PET textile recycling.

Keywords: PET, decoloring, disperse dye, textile recycle

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Authors: Nguyen Cao Nguyen, Krasimir I. Ivanov, Penka S. Zapryanova

Abstract:

The present study was carried out to investigate the interaction of foliar applied zinc with other elements in Phyllanthus amarus plants. The plant samples for our experiment were collected from Lam Dong province, Vietnam. Seven suspension solutions of nanosized zinc hydroxide nitrate (Zn₅(OH)₈(NO₃)₂·2H₂O) with different Zn concentration were used. Fertilization and irrigation were the same for all variants. The Zn content and the content of selected micro (Cu, Fe, Mn) and macro (Ca, Mg, P and K) nutrients in plant roots, and stems and leaves were determined. It was concluded that the zinc content of plant roots varies narrowly, with no significant impact of ZnHN fertilization. The same trend can be seen in the content of Cu, Mn, and macronutrients. The zinc content of plant stems and leaves varies within wide limits, with the significant impact of ZnHN fertilization. The trends in the content of Cu, Mn, and macronutrients are kept the same as in the root, whereas the iron trends to increase its content at increasing the zinc content.

Keywords: Phyllanthus amarus, Zinc, Micro and macro elements, foliar fertilizer

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Authors: Tahani Amutairi, Paul May, Neil Allan

Abstract:

Many properties of semiconductor materials (mechanical, electronic, magnetic, and optical) can be significantly modified by introducing a point defect. Diamond offers extraordinary properties as a semiconductor, and doping seems to be a viable method of solving the problem associated with the fabrication of diamond-based electronic devices in order to exploit those properties. The dopants are believed to play a significant role in reducing the energy barrier to conduction and controlling the mobility of the carriers and the resistivity of the film. Although it has been proven that the n-type diamond semiconductor can be obtained with phosphorus doping, the resulting ionisation energy and mobility are still inadequate for practical application. Theoretical studies have revealed that this is partly because the effects of the many phosphorus atoms incorporated in the diamond lattice are compensated by acceptor states. Using spin-polarised hybrid density functional theory and a supercell approach, we explored the effects of bonding one N atom to a P in adjacent substitutional sites in diamond. A range of hybrid functional, including HSE06, B3LYP, PBE0, PBEsol0, and PBE0-13, were used to calculate the formation, binding, and ionisation energies, in order to explore the solubility and stability of the point defect. The equilibrium geometry and the magnetic and electronic structures were analysed and presented in detail. The defect introduces a unique reconstruction in a diamond where one of the C atoms coordinated with the N atom involved in the elongated C-N bond and creates a new bond with the P atom. The simulated infrared spectra of phosphorus-nitrogen defects were investigated with different supercell sizes and found to contain two sharp peaks at the edges of the spectrum, one at a high frequency 1,379 cm⁻¹ and the second appearing at the end range, 234 cm⁻¹, as obtained with the largest supercell (216).

Keywords: DFT, HSE06, B3LYP, PBE0, PBEsol0, PBE0-13

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Authors: Poonam Yadav, Dong Bok Lee

Abstract:

Raman spectroscopy was used for characterization of multi-wall carbon nanotube (MWNT) and Polycarbonate/multi-wall carbon nanotube (PC/MWNT) based fibers with 0.55% and 0.75% of MWNT (PC/MWNT55 and PC/MWNT75). PC/MWNT55 and PC/MWNT75 fibers was prepared by melt spinning device using nanocomposites made by two different route, viz., solvent casting and melt extrusion. Fibers prepared from melt extruded nanocomposites showed smooth and uniform morphology as compared to solvent casting based nanocomposites. The Raman mapping confirmed that the melt extruded based nanocomposites had better dispersion of MWNT in Polycarbonate (PC) than solvent casting carbon nanotube.

Keywords: dispersion, melt extrusion, multi-wall carbon nanotube, mapping

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Authors: Young Min Kim, Dong Gil Shin, Assmelash Assefa Negash

Abstract:

This study describes the application of a single loop organic Rankine cycle (ORC) for recovering waste heat from an excavator. In the case of waste heat recovery of the excavator, the heat of hydraulic oil can be used in the ORC system together with the other waste heat sources including the exhaust gas and engine coolant. The performances of four different cases of single loop ORC systems were studied at the main operating condition, and critical design factors are studied to get the maximum power output from the given waste heat sources. The energy and exergy analysis of the cycles are performed concerning the available heat source to determine the best fluid and system configuration. The analysis demonstrates that the ORC in the excavator increases 14% of the net power output at the main operating condition with a simpler system configuration at a lower expander inlet temperature than in a conventional vehicle engine without the heat of the hydraulic oil.

Keywords: engine, excavator, hydraulic oil, organic Rankine cycle (ORC), waste heat recovery

Procedia PDF Downloads 274

Authors: Dong Wook Lee

Abstract:

This paper presents a method to analyze the stiffness of the expansion joint with structural support using a hybrid method combining computational and analytical methods. Many expansion joints found in tubes and ducts of mechanical structures are designed to absorb thermal expansion mismatch between their structural members and deal with misalignments introduced from the assembly/manufacturing processes. One of the important design perspectives is the system’s vibrational characteristics. We calculate the stiffness as a characterization parameter for structural joint systems using a combined Finite Element Analysis (FEA) and an analytical method. We apply the methods to two sample applications: external configurations of aircraft engines and nuclear power plant structures.

Keywords: expansion joint, expansion joint stiffness, finite element analysis, nuclear power plants, aircraft engine external configurations

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Authors: Phanwipa Pangsri, Yawariyah Weahayee

Abstract:

The lactic acid bacteria (LAB) were isolated from 10 samples of fermented foods (Sa-tor-dong and Bodo) in South locality of Thailand. The 23 isolates of lactic acid bacteria were selected, which were exhibited a clear zone and growth on MRS agar supplemented with CaCO3. All of lactic acid bacteria were tested on morphological and biochemical. The result showed that all isolates were Gram’s positive, non-spore forming but only 10 isolates displayed catalase negative. The 10 isolates including BD 1.1, BD 1.2, BD 2.1, BD2.2, BD 2.3, BD 3.1, BD 4.1, BD 5.2, ST4.1, and ST 5.2 were selected for inhibition activity determination. Only 2 strains (ST 4.1 and BD 2.3) showed inhibition zone on agar, when using Escherichia coli sp. as target strain. The ST 4.1 showed highest inhibition zone on agar, which was selected for probiotic property testing. The ST4.1 isolate could grow in MRS broth containing a high concentration of sodium chloride 6%, bile salts 7%, pH 4-10 and vary temperature at 15-45^oC.

Keywords: lactic acid bacteria, probiotic, antimicrobial, probiotic property testing

Procedia PDF Downloads 350