Search results for: Hong Zhang

Authors: Jovian Cheung, Thomas Kwok, Victor Wong

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Buildings are entwined with smart city developments. Building performance relies heavily on electrical and mechanical (E&M) systems and services accounting for about 40 percent of global energy use. By cohering the advancement of technology as well as energy and operation-efficient initiatives into the buildings, people are enabled to raise building performance and enhance the sustainability of the built environment in their daily lives. Digital transformation in the buildings is the profound development of the city to leverage the changes and opportunities of digital technologies To optimize the building performance, intelligent power quality and energy management system is developed for transforming data into actions. The system is formed by interfacing and integrating legacy metering and internet of things technologies in the building and applying big data techniques. It provides operation and energy profile and actionable insights of a building, which enables to optimize the building performance through raising people awareness on E&M services and energy consumption, predicting the operation of E&M systems, benchmarking the building performance, and prioritizing assets and energy management opportunities. The intelligent power quality and energy management system comprises four elements, namely the Integrated Building Performance Map, Building Performance Dashboard, Power Quality Analysis, and Energy Performance Analysis. It provides predictive operation sequence of E&M systems response to the built environment and building activities. The system collects the live operating conditions of E&M systems over time to identify abnormal system performance, predict failure trends and alert users before anticipating system failure. The actionable insights collected can also be used for system design enhancement in future. This paper will illustrate how intelligent power quality and energy management system provides operation and energy profile to optimize the building performance and actionable insights to revitalize an existing building into a smart building. The system is driving building performance optimization and supporting in developing Hong Kong into a suitable smart city to be admired.

Keywords: intelligent buildings, internet of things technologies, big data analytics, predictive operation and maintenance, building performance

Procedia PDF Downloads 127

Authors: Fang Liu, JunShuai Xue, JiaJia Yao, XueYan Yang, ZuMao Li, GuanLin Wu, HePeng Zhang, ZhiPeng Sun

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III-Nitride resonant tunneling diode (RTD) is one of the most promising candidates for multiple-valued logic (MVL) elements. Here, we report a monolithic integration of GaN resonant tunneling diodes to realize multiple negative differential resistance (NDR) regions for MVL application. GaN RTDs, composed of a 2 nm quantum well embedded in two 1 nm quantum barriers, are grown by plasma-assisted molecular beam epitaxy on free-standing c-plane GaN substrates. Negative differential resistance characteristic with a peak current density of 178 kA/cm² in conjunction with a peak-to-valley current ratio (PVCR) of 2.07 is observed. Statistical properties exhibit high consistency showing a peak current density standard deviation of almost 1%, laying the foundation for the monolithic integration. After complete electrical isolation, two diodes of the designed same area are connected in series. By solving the Poisson equation and Schrodinger equation in one dimension, the energy band structure is calculated to explain the transport mechanism of the differential negative resistance phenomenon. Resonant tunneling events in a sequence of the series-connected RTD pair (SCRTD) form multiple NDR regions with nearly equal peak current, obtaining three stable operating states corresponding to ternary logic. A frequency multiplier circuit achieved using this integration is demonstrated, attesting to the robustness of this multiple peaks feature. This article presents a monolithic integration of SCRTD with multiple NDR regions driven by the resonant tunneling mechanism, which can be applied to a multiple-valued logic field, promising a fast operation speed and a great reduction of circuit complexity and demonstrating a new solution for nitride devices to break through the limitations of binary logic.

Keywords: GaN resonant tunneling diode, multiple-valued logic system, frequency multiplier, negative differential resistance, peak-to-valley current ratio

Procedia PDF Downloads 51

Authors: Yaw Opoku-Damoah, Run Zhang, Hang Thu Ta, Zhi Ping Xu

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Gas therapy is still at an early stage of research and development. Even though most gasotransmitters have proven their therapeutic potential, their handling, delivery, and controlled release have been extremely challenging. This research work employs a versatile nanosystem that is capable of delivering a gasotransmitter in the form of a photo-responsive carbon monoxide-releasing molecule (CORM) for targeted cancer therapy. The therapeutic action was mediated by upconversion nanoparticles (UCNPs) designed to transfer bio-friendly low energy near-infrared (NIR) light to ultraviolet (UV) light capable of triggering carbon monoxide (CO) from a water-soluble amphiphilic manganese carbonyl complex CORM incorporated into a carefully designed lipid drug delivery system. Herein, gaseous CO that plays a role as a gasotransmitter with cytotoxic and homeostatic properties was investigated to instigate cellular apoptosis. After successfully synthesizing the drug delivery system, the ability of the system to encapsulate and mediate the sustained release of CO after light excitation was demonstrated. CO fluorescence probe (COFP) was successfully employed to determine the in vitro drug release profile upon NIR light irradiation. The uptake of nanoparticles enhanced by folates and its receptor interaction was also studied for cellular uptake purposes. The anticancer potential of the final lipid nanoparticle Lipid/UCNPs/CORM/FA (LUCF) was also determined by cell viability assay. Intracellular CO release and a subsequent therapeutic action involving ROS production, mitochondrial damage, and CO production was also evaluated. In all, this current project aims to use in vitro studies to determine the potency and efficiency of a NIR-mediated CORM prodrug delivery system.

Keywords: carbon monoxide-releasing molecule, upconversion nanoparticles, site-specific delivery, amphiphilic manganese carbonyl complex, prodrug delivery system.

Procedia PDF Downloads 90

Authors: Manpreet Kaur, Cheol-Hong Min

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The increasing advancement in the robotics equipped with machine vision sensors applied to precision agriculture is a demanding solution for various problems in the agricultural farms. An important issue related with the machine vision system concerns crop row and weed detection. This paper proposes an automatic furrow detection system based on real-time processing for identifying crop rows in maize fields in the presence of weed. This vision system is designed to be installed on the farming vehicles, that is, submitted to gyros, vibration and other undesired movements. The images are captured under image perspective, being affected by above undesired effects. The goal is to identify crop rows for vehicle navigation which includes weed removal, where weeds are identified as plants outside the crop rows. The images quality is affected by different lighting conditions and gaps along the crop rows due to lack of germination and wrong plantation. The proposed image processing method consists of four different processes. First, image segmentation based on HSV (Hue, Saturation, Value) decision tree. The proposed algorithm used HSV color space to discriminate crops, weeds and soil. The region of interest is defined by filtering each of the HSV channels between maximum and minimum threshold values. Then the noises in the images were eliminated by the means of hybrid median filter. Further, mathematical morphological processes, i.e., erosion to remove smaller objects followed by dilation to gradually enlarge the boundaries of regions of foreground pixels was applied. It enhances the image contrast. To accurately detect the position of crop rows, the region of interest is defined by creating a binary mask. The edge detection and Hough transform were applied to detect lines represented in polar coordinates and furrow directions as accumulations on the angle axis in the Hough space. The experimental results show that the method is effective.

Keywords: furrow detection, morphological, HSV, Hough transform

Procedia PDF Downloads 202

Authors: Zhang Qingzhong

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Though there exists an increasing number of research studies on the headquarters-subsidiary relationship, and within this context, there is a focus on subsidiaries' contributory role to multinational corporations (MNC), subsidiary autonomy, and the conditions under which autonomy exerts an effect on subsidiary performance still constitute a subject of debate in the literature. The objective of this research is to study the MNC subsidiary autonomy and performance relationship and the effect of subsidiary entrepreneurial orientation and trust on subsidiary autonomy in the China environment, a phenomenon that has not yet been studied. The research addresses the following three questions: (i) Is subsidiary autonomy associated with MNC subsidiary performance in the China environment? (ii) How do subsidiary entrepreneurship and its trust in headquarters affect the level of subsidiary autonomy and its relationship with subsidiary performance? (iii) Does subsidiary autonomy have a mediating effect on subsidiary performance with subsidiary’s entrepreneurship and trust in headquarters? In the present study, we have reviewed literature and conducted semi-structured interviews with multinational corporation (MNC) subsidiary senior executives in China. Building on our insights from the interviews and taking perspectives from four theories, namely the resource-based view (RBV), resource dependency theory, integration-responsiveness framework, and social exchange theory, as well as the extant articles on subsidiary autonomy, entrepreneurial orientation, trust, and subsidiary performance, we have developed a model and have explored the direct and mediating effects of subsidiary autonomy on subsidiary performance within the framework of the MNC. To test the model, we collected and analyzed data based on cross-industry two waves of an online survey from 102 subsidiaries of MNCs in China. We used structural equation modeling to test measurement, direct effect model, and conceptual framework with hypotheses. Our findings confirm that (a) subsidiary autonomy is positively related to subsidiary performance; (b) subsidiary entrepreneurial orientation is positively related to subsidiary autonomy; (c) subsidiary’s trust in headquarters has a positive effect on subsidiary autonomy; (d) subsidiary autonomy mediates the relationship between entrepreneurial orientation and subsidiary performance; (e) subsidiary autonomy mediates the relationship between trust and subsidiary performance. Our study highlights the important role of subsidiary autonomy in leveraging the resource of subsidiary entrepreneurial orientation and its trust relationship with headquarters to achieve high performance. We discuss the theoretical and managerial implications of the findings and propose directions for future research.

Keywords: subsidiary entrepreneurial orientation, trust, subsidiary autonomy, subsidiary performance

Procedia PDF Downloads 159

Authors: Jin-Hyeong Park, Hong-Seok Kim, Jin-Hyeok Yim, Young-Ji Kim, Dong-Hyeon Kim, Jung-Whan Chon, Kun-Ho Seo

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Salmonella contamination in chicken samples can cause major health problems in humans. However, not only the effects of antibiotic treatment during growth but also the impacts of poultry slaughter line on the prevalence of Salmonella in final chicken meat sold to consumers are unknown. In this study, we compared the isolation rates and antimicrobial resistance of Salmonella between antibiotic-free, conventional, conventional Korean native retail chicken meat samples and clonal divergence of Salmonella isolates by multilocus sequence typing. In addition, the distribution of extended-spectrum β-lactamase (ESBL) genes in ESBL-producing Salmonella isolates was analyzed. A total of 72 retail chicken meat samples (n = 24 antibiotic-free broiler [AFB] chickens, n = 24 conventional broiler [CB] chickens, and n = 24 conventional Korean native [CK] chickens) were collected from local retail markets in Seoul, South Korea. The isolation rates of Salmonella were 66.6% in AFB chickens, 45.8% in CB chickens, and 25% in CK chickens. By analyzing the minimum inhibitory concentrations of β -lactam antibiotics with the disc-diffusion test, we found that 81.2% of Salmonella isolates from AFB chickens, 63.6% of isolates from CB chickens, and 50% of isolates from CK chickens were ESBL producers; all ESBL-positive isolates had the CTX-M-15 genotype. Interestingly, all ESBL-producing Salmonella were revealed as ST16 by multilocus sequence typing. In addition, all CTX-M-15-positive isolates had the genetic platform of blaCTX-M gene (IS26-ISEcp1-blaCTX-M-15-IS903), to the best of our knowledge, this is the first report in Salmonella around the world. The Salmonella ST33 strain (S. Hadar) isolated in this study has never been reported in South Korea. In conclusion, our findings showed that antibiotic-free retail chicken meat products were also largely contaminated with ESBL-producing Salmonella and that their ESBL genes and genetic platforms were the same as those isolated from conventional retail chicken meat products.

Keywords: antibiotic-free poultry, conventional poultry, multilocus sequence typing, extended-spectrum β-lactamase, antimicrobial resistance

Procedia PDF Downloads 246

Authors: Na Zhou, Chun-Lai Zhang, Qing Li, Bingqi Zhu, Xun-Ming Wang

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The understanding of the dynamics of aeolian sand in the Yarlung Zangbo River Valley (YLZBV), southern Qinghai-Tibetan Plateau, including its origins, transportation,and deposition, remains preliminary. In this study, we investigated the extensive origin of aeolian sediments in the YLZBV by analyzing the distribution and composition of sediment’s grain size and geochemical composition in dune sediments collected from the wide river terraces. The major purpose is to characterize the sedimentological and geochemical compositions of these aeolian sediments, trace back to their sources, and understand their influencing factors. As a result, the grain size and geochemistry variations, which showed a significant correlation between grain sizes distribution and element abundances, give a strong evidence that the important part of the aeolian sediments in the downstream areas was firstly derived from the upper reaches by intense fluvial processes. However, the sediments experienced significant mixing process with local inputs and reconstructed by regional wind transportation. The diverse compositions and tight associations in the major and trace element geochemistry between the up- and down-stream aeolian sediments and the local detrital rocks, which were collected from the surrounding mountains, suggest that the upstream aeolian sediments had originated from the various close-range rock types, and experienced intensive mixing processes via aeolian- fluvial dynamics. Sand mass transported by water and wind was roughly estimated to qualify the interplay between the aeolian and fluvial processes controlling the sediment transport, yield, and ultimately shaping the aeolian landforms in the mainstream of the YLZBV.

Keywords: grain size distribution, geochemistry, wind and water load, sand source, Yarlung Zangbo River Valley

Procedia PDF Downloads 58

Authors: Yan Zhang, Felix Kin Peng Hui, Colin Duffield, Caroline X. Gao

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In post-pandemic Australia, it is unclear how building occupant have changed their behaviour in their interaction with buildings and other occupants. This research provides information on occupant behaviour change compared to before the pandemic and examines the predictors for those behaviour changes. This paper analyses survey responses from 2298 building occupants in Melbourne to investigate occupant behaviour change and determinants for those changes one year after the pandemic in Australia. The behaviour changes were grouped into three categories based on respiratory infection routes: (1) fomite: hand-shaking and hand hygiene behaviours; (2) airborne: individual interventions to indoor air quality such as face masking, window openings for occupants working in naturally ventilated space; (3) droplets: social distancing, reducing working hours in the workplace. The survey shows that the pandemic has significantly changed occupants' behaviour in all three categories compared to before the pandemic. The changes are significantly associated with occupants' perceived indoor air quality, indoor environmental cleanliness, and occupant density, demonstrating their growing awareness of respiratory infection risk that influences their health behaviours. The two most significant factors identified from multivariate regressions to drive the behaviour change include occupant risk perception of respiratory infections at the workplace and their observed co-worker's behaviour change. Based on the survey results, the paper provides adjusted estimates for related occupant behaviour parameters. The study also discusses alternatives for managing window operations in naturally ventilated buildings to improve occupant satisfaction. This paper could help Building Managers, and Building Designers understand occupant behaviour change to improve building operations and new building design to enhance occupant experience. Also, building energy modellers and risk assessors may use the findings to adjust occupant behaviour-related parameters to improve the models. The findings contribute to the knowledge of Human-Building Interaction.

Keywords: human-building interaction, risk perception, occupant behaviour, IAQ, COVID-19

Procedia PDF Downloads 39

Authors: Hong Wu, Naiji Lu

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Improvement of health behavior among people with chronic diseases is vital for increasing longevity and enhancing quality of life. This paper researched the causal effects of informal care on the compliance with doctor’s health advices – smoking control, dietetic regulation, weight control and keep exercising – among older people with chronic diseases in China, which is facing the challenge of aging. We addressed the selection bias by using propensity score matching in the estimation process. We used the 2011-2012 national baseline data of the China Health and Retirement Longitudinal Study. Our results showed informal care can help improve health behavior of older people. First, informal care improved the compliance of smoking controls: whether smoke, frequency of smoking, and the time lag between wake up and the first cigarette was all lower for these older people with informal care; Second, for dietetic regulation, older people with informal care had more meals every day than older people without informal care; Third, three variables: BMI, whether gain weight and whether lose weight were used to measure the outcome of weight control. There were no significant difference between group with informal care and that without for BMI and the possibility of losing weight. Older people with informal care had lower possibility of gain weight than that without; Last, for the advice of keeping exercising, informal care increased the probability of walking exercise, however, the difference between groups for moderate and vigorous exercise were not significant. Our results indicate policy makers who aim to decrease accidents should take informal care to elders into account and provide an appropriate policy to meet the demand of informal care. Our birth policy and postponed retirement policy may decrease the informal caregiving hours, so adjustments of these policies are important and urgent to meet the current situation of aged tendency of population. In addition, government could give more support to develop organizations to provide formal care, such as nursing home. We infer that formal care is also useful for health behavior improvements.

Keywords: chronic diseases, compliance, CHARLS, health advice, informal care, older people, propensity score matching

Procedia PDF Downloads 376

Authors: Xiaobin Liang, Wei Liang, Laibin Zhang, Xiaoyan Guo

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Pipelines pass through coal mined gobs inevitably in the mining area, the stability of which has great influence on the safety of pipelines. After extensive literature study and field research, it was found that there are a few risk assessment methods for coal mined gob pipelines, and there is a lack of data on the gob sites. Therefore, the fuzzy comprehensive evaluation method is widely used based on expert opinions. However, the subjective opinions or lack of experience of individual experts may lead to inaccurate evaluation results. Hence the accuracy of the results needs to be further improved. This paper presents a comprehensive approach to achieve this purpose by combining bow-tie model and cloud inference. The specific evaluation process is as follows: First, a bow-tie model composed of a fault tree and an event tree is established to graphically illustrate the probability and consequence indicators of pipeline failure. Second, the interval estimation method can be scored in the form of intervals to improve the accuracy of the results, and the censored mean algorithm is used to remove the maximum and minimum values of the score to improve the stability of the results. The golden section method is used to determine the weight of the indicators and reduce the subjectivity of index weights. Third, the failure probability and failure consequence scores of the pipeline are converted into three numerical features by using cloud inference. The cloud inference can better describe the ambiguity and volatility of the results which can better describe the volatility of the risk level. Finally, the cloud drop graphs of failure probability and failure consequences can be expressed, which intuitively and accurately illustrate the ambiguity and randomness of the results. A case study of a coal mine gob pipeline carrying natural gas has been investigated to validate the utility of the proposed method. The evaluation results of this case show that the probability of failure of the pipeline is very low, the consequences of failure are more serious, which is consistent with the reality.

Keywords: bow-tie model, natural gas pipeline, coal mine gob, cloud inference

Procedia PDF Downloads 221

Authors: Yuanda Ma, Zhiyong Zhang, Zailin Yang, Guanxixi Jiang

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Anisotropy is very common in underground media, such as rock, sand, and soil. Hence, the dynamic response of anisotropy medium under elastic waves is significantly different from the isotropic one. Moreover, underground heterogeneities and structures, such as pipelines, cylinders, or tunnels, are usually made by composite materials, leading to the anisotropy of these heterogeneities and structures. Both the anisotropy of the underground medium and the heterogeneities have an effect on the surface motion of the ground. Aiming at providing theoretical references for earthquake engineering and seismology, the surface motion of anisotropic half-space with a cylindrical anisotropic inclusion embedded under the SH wave is investigated in this work. Considering the anisotropy of the underground medium, the governing equation with three elastic parameters of SH wave propagation is introduced. Then, based on the complex function method and multipolar coordinates system, the governing equation in the complex plane is obtained. With the help of a pair of transformation, the governing equation is transformed into a standard form. By means of the same methods, the governing equation of SH wave propagation in the cylindrical inclusion with another three elastic parameters is normalized as well. Subsequently, the scattering wave in the half-space and the standing wave in the inclusion is deduced. Different incident wave angle and anisotropy are considered to obtain the reflected wave. Then the unknown coefficients in scattering wave and standing wave are solved by utilizing the continuous condition at the boundary of the inclusion. Through truncating finite terms of the scattering wave and standing wave, the equation of boundary conditions can be calculated by programs. After verifying the convergence and the precision of the calculation, the validity of the calculation is verified by degrading the model of the problem as well. Some parameters which influence the surface displacement of the half-space is considered: dimensionless wave number, dimensionless depth of the inclusion, anisotropic parameters, wave number ratio, shear modulus ratio. Finally, surface displacement amplitude of the half space with different parameters is calculated and discussed.

Keywords: anisotropy, complex function method, sh wave, surface displacement amplitude

Procedia PDF Downloads 95

Authors: He Zhang, Jianxin Yi

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As a clean energy, hydrogen shows many advantages such as renewability, high heat value, and extensive sources and may play an important role in the future society. However, hydrogen is a combustible gas because of its low ignition energy (0.02mJ) and wide explosive limit (4% ~ 74% in air). It is very likely to cause fire hazard or explosion once leakage is happened and not detected in time. Mixed-potential type sensor has attracted much attention in monitoring and detecting hydrogen due to its high response, simple support electronics and long-term stability. Typically, this kind of sensor is consisted of a sensing electrode (SE), a reference electrode (RE) and a solid electrolyte. The SE and RE materials usually display different electrocatalytic abilities to hydrogen. So hydrogen could be detected by measuring the EMF change between the two electrodes. Previous reports indicate that a high-performance sensing electrode is important for improving the sensing characteristics of the sensor. In this report, a planar type mixed-potential hydrogen sensor using La₀.₈Sr₀.₂Cr₀.₅Mn₀.₅O₃₋δ (LSCM) as SE, Pt as RE and yttria-stabilized zirconia (YSZ) as solid electrolyte was developed. The reason for selecting LSCM as sensing electrode is that it shows the high electrocatalytic ability to hydrogen in solid oxide fuel cells. The sensing performance of the fabricated LSCM/YSZ/Pt sensor was tested systemically. The experimental results show that the sensor displays high response to hydrogen. The response values for 100ppm and 1000ppm hydrogen at 450 ºC are -70 mV and -118 mV, respectively. The response time is an important parameter to evaluate a sensor. In this report, the sensor response time decreases with increasing hydrogen concentration and get saturated above 500ppm. The steady response time at 450 ºC is as short as 4s, indicating the sensor shows great potential in practical application to monitor hydrogen. An excellent response repeatability to 100ppm hydrogen at 450 ˚C and a good sensor reproducibility among three sensors were also observed. Meanwhile, the sensor exhibits excellent selectivity to hydrogen compared with several interfering gases such as NO₂, CH₄, CO, C₃H₈ and NH₃. Polarization curves were tested to investigate the sensing mechanism and the results indicated the sensor abide by the mixed-potential mechanism.

Keywords: fire hazard, H₂ sensor, mixed-potential, perovskite

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Authors: Niaz Gharavi, Hexin Zhang

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In the structural timber design, the shear modulus of the timber beam is an important factor that needs to be determined accurately. According to BS EN 408, shear modulus can be determined using torsion test or shear field test method. Although torsion test creates pure shear status in the beam, it does not represent the real-life situation when the beam is in the service. On the other hand, shear field test method creates similar loading situation as in reality. The latter method is based on shear distortion measurement of the beam at the zone with the constant transverse load in the standardized four-point bending test as indicated in BS EN 408. Current testing practice code advised using two metallic arms act as an instrument to measure the diagonal displacement of the constructing square. Timber is not a homogenous material, but a heterogeneous and this characteristic makes timber to undergo a non-uniform deformation. Therefore, the dimensions and the location of the constructing square in the area with the constant transverse force might alter the shear modulus determination. This study aimed to investigate the impact of the shape, size, and location of the square in the shear field test method. A binocular stereo vision system was developed to capture the 3D displacement of a grid of target points. This approach is an accurate and non-contact method to extract the 3D coordination of targeted object using two cameras. Two group of three glue laminated beams were produced and tested by the mean of four-point bending test according to BS EN 408. Group one constructed using two materials, laminated bamboo lumber and structurally graded C24 timber and group two consisted only structurally graded C24 timber. Analysis of Variance (ANOVA) was performed on the acquired data to evaluate the significance of size and location of the square in the determination of shear modulus of the beam. The results have shown that the size of the square is an affecting factor in shear modulus determination. However, the location of the square in the area with the constant shear force does not affect the shear modulus.

Keywords: shear field test method, BS EN 408, timber shear modulus, photogrammetry approach

Procedia PDF Downloads 184

Authors: Fengxia Li, Lufeng Zhang, Haibo Wang

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The tight sandstone gas reservoir in the Xujiahe Formation of the Sichuan Basin has huge reserves, but its utilization rate is low. Fracturing and stimulation are indispensable technologies to unlock their potential and achieve commercial exploitation. Slickwater is the most widely used fracturing fluid system in the fracturing and renovation of tight reservoirs. However, its viscosity is low, its sand-carrying performance is poor, and the risk of sand blockage is high. Increasing the sand carrying capacity by increasing the displacement will increase the frictional resistance of the pipe string, affecting the resistance reduction performance. The variable viscosity slickwater can flexibly switch between different viscosities in real-time online, effectively overcoming problems such as sand carrying and resistance reduction. Based on a self-developed indoor loop friction testing system, a visualization device for proppant transport, and a HAAKE MARS III rheometer, a comprehensive evaluation was conducted on the performance of variable viscosity slickwater, including resistance reduction, rheology, and sand carrying. The indoor experimental results show that: 1. by changing the concentration of drag-reducing agents, the viscosity of the slippery water can be changed between 2~30mPa. s; 2. the drag reduction rate of the variable viscosity slickwater is above 80%, and the shear rate will not reduce the drag reduction rate of the liquid; under indoor experimental conditions, 15mPa. s of variable viscosity and slickwater can basically achieve effective carrying and uniform placement of proppant. The layered fracturing effect of the JiangX well in the dense sandstone of the Xujiahe Formation shows that the drag reduction rate of the variable viscosity slickwater is 80.42%, and the daily production of the single layer after fracturing is over 50000 cubic meters. This study provides theoretical support and on-site experience for promoting the application of variable viscosity slickwater in tight sandstone gas reservoirs.

Keywords: slickwater, hydraulic fracturing, dynamic sand laying, drag reduction rate, rheological properties

Procedia PDF Downloads 46

Authors: Yiqi Sun, Zhiyuan Zhang, Chenkun Ma

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Regeneration of outmoded urban forms and restorative environments are now recognized as major assets towards achieving sustainable development. Shanghai, like many Chinese cities, is now shifting from an agitated industrial past to more livable development schemes. Therefore, a sustainable approach to Shanghai development consists in turning industrial heritage into places with high potential for improving citizen’s daily life as regard to the three pillars of sustainability, namely: environment, economy, and society. As such, this study focuses on the Corniche in Xuhui West Bund district; a former industrial area converted into recreational public spaces in Xuhui West Bund. This area was the birthplace of the aviation industry of China, and many of the industrial features were preserved. Unused areas have been transformed into exhibition halls and green spaces, integrating some of the original industrial, architectural forms. Our case study investigates the effects of this approach associating urban regeneration with restorative design, as well as its impact on the surrounding neighborhood. Information extracted from visitors’ answers to a questionnaire survey; on-site systematic observation, counts, and measurements allowed us to assess the sustainability of this intervention in terms of accessibility, functionality, cultural and restorative qualities. In general, we found that cycling is not highly encouraged by the current design and level of connectivity, while visitors widely acknowledge the enhancement of cultural heritage resulting from the intervention. Moreover, recreational and restorative areas were found to have a very positive effect on local communities. Indeed, such an approach can provide valuable insights on how future interventions in Chinese major cities could take full advantage of existing assets in creating a more environmental, more livable, and culturally richer city.

Keywords: architectural heritage conservation, cultural urban identity, sustainability assessment, restorative environment, urban regeneration

Procedia PDF Downloads 160

Authors: Mhenga Agneta, Li Zhaomin, Zhang Chao

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When velocity is high enough, gas can entrain fluid and carry to the surface, but as time passes by, velocity drops to a critical point where fluids will start to hold up in the tubing and cause liquid loading which prevents gas production and may lead to the death of the well. Foam injection is widely used as one of the methods to unload liquid. Since wells have different characteristics, it is not guaranteed that foam can be applied in all of them and bring successful results. This research presents a technology to optimize the efficiency of foam to unload liquid by air compression. Two methods are used to explain optimization; (i) mathematical formulas are used to solve and explain the myth of how density and critical velocity could be minimized when air is compressed into foaming agents, then the relationship between flow rates and pressure increase which would boost up the bottom hole pressure and increase the velocity to lift liquid to the surface. (ii) Experiments to test foam carryover capacity and stability as a function of time and surfactant concentration whereby three surfactants anionic sodium dodecyl sulfate (SDS), nonionic Triton 100 and cationic hexadecyltrimethylammonium bromide (HDTAB) were probed. The best foaming agents were injected to lift liquid loaded in a created vertical well model of 2.5 cm diameter and 390 cm high steel tubing covered by a transparent glass casing of 5 cm diameter and 450 cm high. The results show that, after injecting foaming agents, liquid unloading was successful by 75%; however, the efficiency of foaming agents to unload liquid increased by 10% with an addition of compressed air at a ratio of 1:1. Measured values and calculated values were compared and brought about ± 3% difference which is a good number. The successful application of the technology indicates that engineers and stakeholders could bring water flooded gas wells back to production with optimized results by firstly paying attention to the type of surfactants (foaming agents) used, concentration of surfactants, flow rates of the injected surfactants then compressing air to the foaming agents at a proper ratio.

Keywords: air compression, foaming agents, gas well, liquid loading

Procedia PDF Downloads 109

Authors: Mohamed Abdalla, Ruixue Cheng, Jianyong Zhang

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In pneumatic conveying, the solids are mixed with air or gas. In industries such as coal fired power stations, blast furnaces for iron making, cement and flour processing, the mass flow rate of solids needs to be monitored or controlled. However the current gas-solids two-phase flow measurement techniques are not as accurate as the flow meters available for the single phase flow. One of the problems that the multi-phase flow meters to face is that the flow profiles vary with measurement locations and conditions of pipe routing, bends, elbows and other restriction devices in conveying system as well as conveying velocity and concentration. To measure solids flow rate or concentration with non-even distribution of solids in gas, a uniform spatial sensitivity is required for a multi-phase flow meter. However, there are not many meters inherently have such property. The circular electrostatic meter is a popular choice for gas-solids flow measurement with its high sensitivity to flow, robust construction, low cost for installation and non-intrusive nature. However such meters have the inherent non-uniform spatial sensitivity. This paper first analyses the spatial sensitivity of circular electrostatic meter in general and then by combining the effect of the sensitivity to a single particle and the sensing volume for a given electrode geometry, the paper reveals first time how a circular electrostatic meter responds to a roping flow stream, which is much more complex than what is believed at present. The paper will provide the recent research findings on spatial sensitivity investigation at the University of Tees side based on Finite element analysis using Ansys Fluent software, including time and frequency domain characteristics and the effect of electrode geometry. The simulation results will be compared tothe experimental results obtained on a large scale (14” diameter) rig. The purpose of this research is paving a way to achieve a uniform spatial sensitivity for the circular electrostatic sensor by mean of compensation so as to improve overall accuracy of gas-solids flow measurement.

Keywords: spatial sensitivity, electrostatic sensor, pneumatic conveying, Ansys Fluent software

Procedia PDF Downloads 328

Authors: Yulin Zhang, Kaixi Dong, Guozhen Zhao

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Background: Different levels of life satisfaction are associated with some individual differences. Understanding the mechanism between them will help to enhance an individual’s well-being. On the one hand, traditional personality such as extraversion has been considered as the most stable and effective factor in predicting life satisfaction to the author’s best knowledge. On the other, individual emotional difference, such as alexithymia (difficulties identifying and describing one’s own feelings), is also closely related to life satisfaction. With the development of positive psychology, positive personalities such as virtues attract wide attention. And according to the broaden-and-build theory, social connectivity may mediate between emotion and life satisfaction. Therefore, the current study aims to explore the mediating role of social connectivity in the effect of positive personality and alexithymia on life satisfaction. Method: This study was conducted with 318 healthy Chinese college students whose age range from 18 to 30. Positive personality (including interpersonal, vitality, and cautiousness) was measured by the Chinese version of Values in Action Inventory of Strengths (VIA-IS). Alexithymia was measured by the Toronto Alexithymia Scale (TAS), and life satisfaction was measured by Satisfaction With Life Scale (SWLS). And social connectivity was measured by six items which have been used in previous studies. Each scale showed high reliability and validity. The mediating model was examined in Mplus 7.2 within a structural equation modeling (SEM) framework. Findings: The model fitted well and results revealed that both positive personality (95% confidence interval of indirect effect was [0.023, 0.097]) and alexithymia (95% confidence interval of indirect effect was [-0.270, -0.089]) predicted life satisfaction level significantly through social connectivity. Also, only positive personality significantly and directly predicted life satisfaction compared to alexithymia (95% confidence interval of direct effect was [0.109, 0.260]). Conclusion: Alexithymia predicts life satisfaction only through social connectivity, which emphasizes the importance of social bonding in enhancing the well-being of Chinese college students with alexithymia. And the positive personality can predict life satisfaction directly or through social connectivity, which provides implications for enhancing the well-being of Chinese college students by cultivating their virtue and positive psychological quality.

Keywords: alexithymia, life satisfaction, positive personality, social connectivity

Procedia PDF Downloads 142

Authors: Nguyen Quynh Trang, Nguyễn Thị Hông Nhung

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The study aimed to identify the effectiveness of using the mind map technique to enhance students’ medical vocabulary retention among a group of students at a higher education institution - Thai Nguyen University of Medicine and Pharmacy during the first semester of the school year 2022-2023. The research employed a quasi-experimental method, exploring primary sources such as questionnaires and the analyzed results of pre-and-post tests. Almost teachers and students showed high preferences for the implementation of the mind map technique in language teaching and learning. Furthermore, results from the pre-and-post tests between the experimental group and control one pointed out that this technique brought back positive academic performance in teaching and learning English. The research findings revealed that there should be more supportive policies to evoke the use of the mind map technique in a pedagogical context. Aim of the Study: The purpose of this research was to investigate whether using mind mapping can help students to enhance nursing students’ medical vocabulary retention and to assess the students’ attitudes toward using mind mapping as a tool to improve their vocabulary. The methodology of the study: The research employed a quasi-experimental method, exploring primary sources such as questionnaires and the analyzed results of pre-and-post tests. The contribution of the study: The research contributed to the innovation of teaching vocabulary methods for English teachers at a higher education institution. Moreover, the research helped the English teachers and the administrators at a university evoke and maintain the motivation of students not only in English classes but also in other subjects. The findings of this research were beneficial to teachers, students, and researchers interested in using mind mapping to teach and learn English vocabulary. The research explored and proved the effectiveness of applying mind mapping in teaching and learning English vocabulary. Therefore, teaching and learning activities were conducted more and more effectively and helped students overcome challenges in remembering vocabulary and creating motivation to learn English vocabulary.

Keywords: medical vocabulary retention, mind map technique, nursing students, medical vocabulary

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Authors: Ju-Hong Lee, Ching-Wei Liao

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Adaptive beamforming using antenna array of sensors is useful in the process of adaptively detecting and preserving the presence of the desired signal while suppressing the interference and the background noise. For conventional adaptive array beamforming, we require a prior information of either the impinging direction or the waveform of the desired signal to adapt the weights. The adaptive weights of an antenna array beamformer under a steered-beam constraint are calculated by minimizing the output power of the beamformer subject to the constraint that forces the beamformer to make a constant response in the steering direction. Hence, the performance of the beamformer is very sensitive to the accuracy of the steering operation. In the literature, it is well known that the performance of an adaptive beamformer will be deteriorated by any steering angle error encountered in many practical applications, e.g., the wireless communication systems with massive antennas deployed at the base station and user equipment. Hence, developing effective signal processing techniques to deal with the problem due to steering angle error for array beamforming systems has become an important research work. In this paper, we present an effective signal processing technique for constructing an adaptive beamformer against the steering angle error. The proposed array beamformer adaptively estimates the actual direction of the desired signal by using the presumed steering vector and the received array data snapshots. Based on the presumed steering vector and a preset angle range for steering mismatch tolerance, we first create a matrix related to the direction vector of signal sources. Two projection matrices are generated from the matrix. The projection matrix associated with the desired signal information and the received array data are utilized to iteratively estimate the actual direction vector of the desired signal. The estimated direction vector of the desired signal is then used for appropriately finding the quiescent weight vector. The other projection matrix is set to be the signal blocking matrix required for performing adaptive beamforming. Accordingly, the proposed beamformer consists of adaptive quiescent weights and partially adaptive weights. Several computer simulation examples are provided for evaluating and comparing the proposed technique with the existing robust techniques.

Keywords: adaptive beamforming, robustness, signal blocking, steering angle error

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Authors: Yan Lu, Song Hong, Janakiraman Udaiyappan, Aarti Nagayach, Quoc-Viet A. Duong, Masao Morita, Shun Saito, Yuichi Kobayashi, Yuhai, Zhao, Hongying Peng, Nicholas B. Pham, Walter J Lukiw, Christopher A. Vuong, Nicolas G. Bazan

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Aims: Neurodegeneration and behavior dysfunction occurs in patients with Alzheimer's Disease (AD), and as the disease progresses many patients develop cognitive impairment. 5XFAD mouse model of AD is widely used to study AD pathogenesis and treatment. This study aimed to investigate the effect of maresin like 1 (MaR-L1) treatment in AD pathology using 5XFAD mice. Methods: We tested 12-month-old male 5XFAD mice and wild type control mice treated with MaR-L1 in a battery of behavioral tasks. We performed open field test, beam walking test, clasping test, inverted grid test, acetone test, marble burring test, elevated plus maze test, cross maze test and novel object recognition test. We also studied neuronal loss, amyloid β burden, and inflammation in the brains of 5XFAD mice using immunohistology and Western blotting. Results: MaR-L1 treatment to the 5XFAD mice showed improved cognitive function of 5XFAD mice. MaR-L1 showed decreased anxiety behavior in open field test and marble burring test, increased muscular strength in the beam walking test, clasping test and inverted grid test. Cognitive function was improved in MaR-L1 treated 5XFAD mice in the novel object recognition test. MaR-L1 prevented neuronal loss and aberrant inflammation. Conclusion: Our finding suggests that behavioral abnormalities were normalized by the administration of MaR-L1 and the neuroprotective role of MaR-L1 in the AD. It also indicates that MaR-L1 treatment is able to prevent and or ameliorate neuronal loss and aberrant inflammation. Further experiments to validate the results are warranted using other AD models in the future.

Keywords: Alzheimer's disease, motor and cognitive behavior, 5XFAD mice, Maresin Like 1, microglial cell, astrocyte, neurodegeneration, inflammation, resolution of inflammation

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Authors: Kan Yu, Khui Hung Lee, Eben Afrifa-Yamoah, Jing Guo, Katrina Harrison, Jack Goldblatt, Nicholas Pachter, Jitian Xiao, Guicheng Brad Zhang

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Background and Significance of the Study: Congenital Heart Defects (CHDs) are the most common malformation at birth and one of the leading causes of infant death. Although the exact etiology remains a significant challenge, epigenetic modifications, such as DNA methylation, are thought to contribute to the pathogenesis of congenital heart defects. At present, no existing DNA methylation biomarkers are used for early detection of CHDs. The existing CHD diagnostic techniques are time-consuming and costly and can only be used to diagnose CHDs after an infant was born. The present study employed a machine learning technique to analyse genome-wide methylation data in children with and without CHDs with the aim to find methylation biomarkers for CHDs. Methods: The Illumina Human Methylation EPIC BeadChip was used to screen the genome‐wide DNA methylation profiles of 24 infants diagnosed with congenital heart defects and 24 healthy infants without congenital heart defects. Primary pre-processing was conducted by using RnBeads and limma packages. The methylation levels of top 600 genes with the lowest p-value were selected and further investigated by using a random forest approach. ROC curves were used to analyse the sensitivity and specificity of each biomarker in both training and test sample sets. The functionalities of selected genes with high sensitivity and specificity were then assessed in molecular processes. Major Findings of the Study: Three genes (MIR663, FGF3, and FAM64A) were identified from both training and validating data by random forests with an average sensitivity and specificity of 85% and 95%. GO analyses for the top 600 genes showed that these putative differentially methylated genes were primarily associated with regulation of lipid metabolic process, protein-containing complex localization, and Notch signalling pathway. The present findings highlight that aberrant DNA methylation may play a significant role in the pathogenesis of congenital heart defects.

Keywords: biomarker, congenital heart defects, DNA methylation, random forest

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Authors: Aqsa Kanwal, Min Zhang, Faisal Sharaf, Li Chengtao

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The globe is facing increasing challenges of plastic pollution due to single-use of plastic-based packaging material. The plastic material is continuously being dumped into the natural environment, which causes serious harm to the entire ecosystem. Polymer degradation in nature is very difficult, so the use of biodegradable polymers instead of conventional polymers can mitigate this issue. Due to the good mechanical properties and biodegradability, aliphatic-aromatic polymers are being widely commercialized. Due to the advancement in molecular biology, many studies have reported specific microbes that can effectively degrade PBAT. Aliphatic polyesters undergo hydrolytic cleavage of ester groups, so they can be easily degraded by microorganisms. In this study, we investigated the enzymatic degradation of poly (butylene adipate terephthalate) (PBAT) copolymer using lipase B from Candida Antarctica (CALB). Results of the study displayed approximately 5.16 % loss in PBAT mass after 2 days which significantly increased to approximately 15.7 % at the end of the experiment (12 days) as compared to blank. The pH of the degradation solution also displayed significant reduction and reached the minimum value of 6.85 at the end of the experiment. The structure and morphology of PBAT after degradation were characterized by FTIR, XRD, SEM, and TGA. FTIR analysis showed that after degradation many peaks become weaker and the peak at 2950 cm-1 almost disappeared after 12 days. The XRD results indicated that as the degradation time increases the intensity of diffraction peaks slightly increases as compared to the blank PBAT. TGA analysis also confirmed the successful degradation of PBAT with time. SEM micrographs further confirmed that degradation has occurred. Hence, biodegradable polymers can widely be used. The effect of PBAT biodegradation on plant growth was also studied and it was found that PBAT has no toxic effect on the growth of plants. Hence PBAT can be employed in a wide range of applications.

Keywords: aliphatic-aromatic co-polyesters, polybutylene adipate terephthalate, lipase (CALB), biodegradation, plant growth

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Authors: Wenjie Wu, Peng Cheng, Zehua Zhang, Fei Luo, Feng Wu, Min Zhong, Jianzhong Xu

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Background: There has been limited research into the therapeutic efficacy of rapid diagnosis of spinal tuberculosis complicated with pulmonary tuberculosis. We attempted to discover whether the utilization of a DNA microarray assay to detect multidrug-resistant spinal tuberculosis complicated with pulmonary tuberculosis can improve clinical outcomes. Methods: A prospective study was conducted from February 2006 to September 2015. One hundred and forty-three consecutive culture–confirmed, clinically and imaging diagnosed MDR-TB patients with spinal tuberculosis complicated by pulmonary tuberculosis were enrolled into the study. The initial time to treatment for MDR-TB, the method of infection control, radiological indicators of spinal tubercular infectious foci, culture conversion, and adverse drug reactions were compared with the standard culture methods. Results: Of the total of 143 MDR-TB patients, 68 (47.6%) were diagnosed by conventional culture methods and 75 (52.4%) following the implementation of detection using the DNA microarray. Patients in the microarray group began rational use of the second-line drugs schedule more speedily than sufferers in the culture group (17.3 vs. 74.1 days). Among patients were admitted to a general tuberculosis ward, those from the microarray group spent less time in the ward than those from the culture group (7.8 vs. 49.2 days). In those patients with six months follow-up (n=134), patients in the microarray group had a higher rate of sputum negativity conversion at six months (89% vs. 73%). In the microarray group, the rate of drug adverse reactions was significantly lower (22.2% vs. 67.7%). At the same time, they had a more obvious reduction of the area with spinal tuberculous lesions in radiological examinations (77% vs. 108%). Conclusions: The application of the CapitalBio™ DNA Microarray assay caused noteworthy clinical advances including an earlier time to begin MDR-TB treatment, increased sputum culture conversion, improved infection control measures and better radiographical results

Keywords: tuberculosis, multidrug-resistant, tuberculous spondylitis, DNA microarray, clinical outcomes

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Authors: Seunghwan Seo, Woo-Seok Lee, Ji-Sun Shin, Young Kyoung Rhee, Chang-Won Cho, Hee-Do Hong, Kyung-Tae Lee

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Doenjang, known as traditional Korean food, is product of a natural mixed fermentation process carried out by lactic acid bacteria (LAB). Lactobacillus sakei K040706 (K040706) has been accepted as the most populous LAB in over ripened doenjang. Recently, we reported the immunostimulatory effects of K040706 in RAW 264.7 macrophages and in a cyclophosphamide-induced mouse model. In this study, we investigated the ameliorative effects of K040706 in a dextran sulfate sodium (DSS)-induced colitis mouse model. We induced colitis using DSS in 5-week-ICR mice over 14 days with or without 0.1, 1 g/kg/day K040706 orally. The body weight, stool consistency, and gross bleeding were recorded for determination of the disease activity index (DAI). At the end of treatment, animals were sacrificed and colonic tissues were collected and subjected to histological experiments and myeloperoxidase (MPO) accumulation, cytokine determination, qRT-PCR and Western blot analysis. Results showed that K040706 significantly attenuated DSS-induced DAI score, shortening of colon length, enlargement of spleen and immune cell infiltrations into colonic tissues. Histological examinations indicated that K040706 suppressed edema, mucosal damage, and the loss of crypts induced by DSS. These results were correlated with the restoration of tight junction protein expression, such as, ZO-1 and occludin in K040706-treated mice. Moreover, K040706 reduced the abnormal secretions and mRNA expressions of pro-inflammatory mediators, such as nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6). DSS-induced mRNA expression of intercellular adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM) in colonic tissues was also downregulated by K040706 treatment. Furthermore, K040706 suppressed the protein and mRNA expression of toll-like receptor 4 (TLR4) and phosphorylation of NF-κB and signal transducer and activator of transcription 3 (STAT3). These results suggest that K040706 has an anti-colitic effect by inhibition of intestinal inflammatory responses in DSS-induced colitic mice.

Keywords: Lactobacillus sakei, NF-κB, STAT3, ulcerative colitis

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Authors: Mohammad Nasb, Muhammad Rehan, Chen Hong

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Background Meniscus defects critically alter knee function and lead to degenerative changes. Regenerative medicine applications including stem cell transplantation have showed a promising efficacy in finding alternatives to overcome traditional treatment limitations. However, stem cell therapy remains limited due to the substantially reduced viability and inhibitory microenvironment. Since tissue growth and repair are under the control of biochemical and mechanical signals, several approaches have recently been investigated (e.g., low intensity pulsed ultrasound [LIPUS]) to promote the regeneration process. This study employed LIPUS to improve growth and osteogenic differentiation of mesenchymal stem cells derived from human embryonic stem cells to improve the regeneration of meniscus tissue. Methodology: The Mesenchymal stromal cells (MSCs) were transplanted into the epicenter of the injured meniscus in rabbits, which were randomized into two main groups: a treatment group (n=32 New Zealand rabbits) including 4 subgroups of 8 rabbits in each subgroup (LIPUS treatment, MSC treatment, LIPUS with MSC and control), and a second group (n=9) to track implanted cells and their progeny using green fluorescence protein (GFP). GFP consists of the MSC and LIPUS-MSC combination subgroups. Rabbits were then subjected to histological, immunohistochemistry, and MRI assessment. Results: The quantity of the newly regenerated tissue in the combination treatment group that had Ultrasound irradiation after mesenchymal stem cells were better at all end points. Likewise, Tissue quality scores were also greater in knees treated with both approaches compared with controls and single treatment at all end points, achieving significance at twelve and twenty-four weeks [p < 0.05], and [p = 0.008] at twelve weeks. Differentiation into type-I and II collagen-expressing cells were higher in the combination group at up to twenty-four weeks. Conclusions: the combination of mesenchymal stem cells and LIPUS showed greater adhering to the sites of meniscus injury, differentiate into cells resembling meniscal fibrochondrocytes, and improve both quality and quantity of meniscal regeneration.

Keywords: stem cells, regenerative medicine, osteoarthritis, knee

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Authors: Fang Liu, JunShuai Xue, JiaJia Yao, GuanLin Wu, ZuMaoLi, XueYan Yang, HePeng Zhang, ZhiPeng Sun

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Terahertz spectra is in great demand since last two decades for many photonic and electronic applications. III-Nitride resonant tunneling diode is one of the promising candidates for portable and compact THz sources. Room temperature microwave oscillator based on GaN/AlN resonant tunneling diode was reported in this work. The devices, grown by plasma-assisted molecular-beam epitaxy on free-standing c-plane GaN substrates, exhibit highly repeatable and robust negative differential resistance (NDR) characteristics at room temperature. To improve the interface quality at the active region in RTD, indium surfactant assisted growth is adopted to enhance the surface mobility of metal atoms on growing film front. Thanks to the lowered valley current associated with the suppression of threading dislocation scattering on low dislocation GaN substrate, a positive peak current density of record-high 2.1 MA/cm2 in conjunction with a peak-to-valley current ratio (PVCR) of 1.2 are obtained, which is the best results reported in nitride-based RTDs up to now considering the peak current density and PVCR values simultaneously. When biased within the NDR region, microwave oscillations are measured with a fundamental frequency of 0.31 GHz, yielding an output power of 5.37 µW. Impedance mismatch results in the limited output power and oscillation frequency described above. The actual measured intrinsic capacitance is only 30fF. Using a small-signal equivalent circuit model, the maximum intrinsic frequency of oscillation for these diodes is estimated to be ~260GHz. This work demonstrates a microwave oscillator based on resonant tunneling effect, which can meet the demands of terahertz spectral devices, more importantly providing guidance for the fabrication of the complex nitride terahertz and quantum effect devices.

Keywords: GaN resonant tunneling diode, peak current density, microwave oscillation, intrinsic capacitance

Procedia PDF Downloads 103

Authors: Leijun Zhang

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Reading literacy has become a powerful tool for academic success and an essential goal of education. The ability to read is not only fundamental for pupils’ academic success but also a prerequisite for successful participation in today’s vastly expanding multi-literate textual environment. It is also important to recognize that, in many educational settings, students are expected to learn a foreign/second language for successful participation in the increasingly globalized world. Therefore, it is crucial to help learners become skilled foreign-language readers. Research indicates that students’ reading comprehension can be significantly improved through explicit instruction of multiple reading strategies. Despite the wealth of research on how to enhance learners’ reading comprehension achievement by identifying an enormous range of reading strategies and techniques for assisting students in comprehending specific texts, relatively scattered studies have centered on whether these reading comprehension strategies and techniques are used in classrooms, especially in Chinese academic settings. Given the central role of ‘the teacher’ in reading instruction, the study investigates the degree of importance that EFL teachers attach to reading comprehension strategies and their classroom employment of those strategies in secondary schools in China. It also explores the efficiency of reading strategy instruction on pupils’ reading comprehension performance. As a mix-method study, the analysis drew on data from a quantitative survey and interviews with seven teachers. The study revealed that the EFL teachers had positive attitudes toward the use of cognitive strategies despite their insufficient knowledge about and limited attention to the metacognitive strategies and supporting strategies. Regarding the selection of reading strategies for instruction, the mandated curriculum and high-stakes examinations, text features and demands, teaching preparation programs and their own EFL reading experiences were the major criteria in their responses, while few teachers took into account the learner needs in their choice of reading strategies. Although many teachers agreed upon the efficiency of reading strategy instruction in developing students’ reading comprehension competence, three challenges were identified in their implementation of the strategy instruction. The study provides some insights into reading strategy instruction in EFL contexts and proposes implications for curriculum innovation, teacher professional development, and reading instruction research.

Keywords: reading comprehension strategies, EFL reading instruction, language teacher cognition, teacher education

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Authors: Andrew Fox, Tao Zhang, Yuanhong Zhao, Qingping Yang

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The furniture manufacturing industry has been slow in general to adopt the latest manufacturing technologies, historically relying heavily upon specialised conventional machinery. This approach not only requires high levels of specialist process knowledge, training, and capital investment but also suffers from significant subtractive manufacturing waste and high logistics costs due to the requirement for centralised manufacturing, with high levels of furniture product not re-cycled or re-used. This paper aims to address the problems by introducing suitable digital manufacturing technologies to create step changes in furniture manufacturing design, as the traditional design practices have been reported as building in 80% of environmental impact. In this paper, a 3D printing robot for furniture manufacturing is reported. The 3D printing robot mainly comprises a KUKA industrial robot, an Arduino microprocessor, and a self-assembled screw fed extruder. Compared to traditional 3D printer, the 3D printing robot has larger motion range and can be easily upgraded to enlarge the maximum size of the printed object. Generative design is also investigated in this paper, aiming to establish a combined design methodology that allows assessment of goals, constraints, materials, and manufacturing processes simultaneously. ‘Matrixing’ for part amalgamation and product performance optimisation is enabled. The generative design goals of integrated waste reduction increased manufacturing efficiency, optimised product performance, and reduced environmental impact institute a truly lean and innovative future design methodology. In addition, there is massive future potential to leverage Single Minute Exchange of Die (SMED) theory through generative design post-processing of geometry for robot manufacture, resulting in ‘mass customised’ furniture with virtually no setup requirements. These generatively designed products can be manufactured using the robot based additive manufacturing. Essentially, the 3D printing robot is already functional; some initial goals have been achieved and are also presented in this paper.

Keywords: additive manufacturing, generative design, robot, sustainability

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Authors: Wenjun Zhang, Thao Thi Le, Dongyup Shin, Jong Min Kim

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Electrochemical hydrogen peroxide (H₂O₂) synthesis holds significant promise for decentralized environmental remediation through the electro-Fenton process. However, challenges persist, such as the absence of robust electrocatalysts for the selective two-electron oxygen reduction reaction (2e⁻ ORR) and the high cost and sluggish kinetics of conventional electro-Fenton systems in treating highly concentrated wastewater. This study introduces an efficient water treatment system for removing substantial quantities of organic pollutants using an advanced electro-Fenton system coupled with a high-valent NiO catalyst. By employing a precipitation method involving crystal facet and cation vacancy engineering, a trivalent Ni (Ni³⁺)-rich NiO catalyst with a (111)-domain-exposed crystal facet, named {111}-NivO, was synthesized. This catalyst exhibited a remarkable 96% selectivity and a high mass activity of 59 A g⁻¹ for H₂O₂ production, outperforming all previously reported Ni-based catalysts. Furthermore, an advanced electro-Fenton system, integrated with a flow cell for electrochemical H₂O₂ production, was utilized to achieve 100% removal of 50 ppm bisphenol A (BPA) in 200 mL of wastewater under heavy-duty conditions, reaching a superior rapid degradation rate (4 min, k = 1.125 min⁻¹), approximately 102 times faster than the conventional electro-Fenton system. The hyper-efficiency is attributed to the continuous and appropriate supply of H₂O₂, the provision of O₂, and the timely recycling of the electrolyte under high current density operation. This catalyst also demonstrated a 93% removal of total organic carbon after 2 hours of operation and can be applied for efficient removal of highly concentrated phenol pollutants from aqueous systems, which opens new avenues for wastewater treatment.

Keywords: hydrogen peroxide production, nickel oxides, crystal facet and cation vacancy engineering, wastewater treatment, flow cell, electro-Fenton

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