39 research outputs found
City Branding Practices in Hunan Province and Hubei Province Based on Ecological Modernization
This thesis aims to analyze the city branding practices related to Ecological Modernization of cities in Hunan province and Hubei province, which are both located in the Central Region of China.Engineering and Policy Analysi
Occupational Health and Safety in China: A Systematic Analysis of Research Trends and Future Perspectives
The frequent occurrence of various occupational accidents has resulted in significant casualties and occupational disease issues, which hinder economic and social development seriously. The promotion and enhancement of occupational health and safety (OHS) require greater efforts to be made to achieve sustainable economic development, particularly in developing countries. With remarkable progress and achievements that have been made in terms of OHS in China, a systematic and thorough review is needed to gain insight into the development process, current status, and research trends regarding OHS in China. Additionally, pathways for future work need to be discussed to boost the OHS development in China in the new era. Therefore, a systematic literature review is performed in this study to investigate the development of OHS in China with the help of a bibliometric analysis. Firstly, a total of 5675 publications related to OHS in China between 1979 and 2022 were collected from the Web of Science Core Collection (WoSCC) and the Chinese Science Citation Database (CSCD) before being refined manually. Then, the temporal distribution and journal sources of the collected publications were analyzed before the collaboration networks of the “productive institutions” and “productive authors” were discussed. Furthermore, the key research topics (e.g., disease prevention, psychological safety, occupational exposure) and dominant research methods (e.g., epidemiological methods, risk modeling) associated with OHS during different periods were identified and discussed based on the keywords and bibliographic analysis. Finally, the current needs and promising pathways for future work were discussed. It is suggested that the prevention and control of conventional and new occupational diseases, the protection of workers’ occupational health rights and interests, the development and implementation of advanced technologies for OHS, and the development of more sophisticated and efficient health and safety risk assessment models may be focused on to accelerate the development of OHS in China. This study systematically reviews the development processes, current status, and future prospects regarding OHS in China. The results of this study provide valuable insights for researchers and practitioners who are involved in the Chinese OHS development, and the promising pathways for future works are suggested to boost the OHS development in China.Safety and Security Scienc
Comparing the stretching technique and the wavelet cross-spectrum technique for measuring stress-induced wave-velocity changes in concrete
Coda wave interferometry (CWI) holds promise as a technique for concrete stress monitoring. This is because the coda, which consists of multiply scattered arrivals, is the result of propagation through the medium over large distances. As such, it is sensitive to both minute structural changes and small velocity changes in that medium. Previous studies focusing on concrete have predominantly utilized the time-domain-based stretching technique to measure travel-time changes. There is, however, a lack of consensus on how to quantify these changes effectively. In this study, we conduct a systematic comparison between two techniques, namely the stretching technique and the wavelet cross-spectrum (WCS) technique, for measuring stress-induced velocity changes in a cylindrical concrete sample. Our comparison focuses on two key aspects: (i) stability against cycle skipping and (ii) consistency in retrieving velocity changes. Experimental results reveal that both the WCS technique and the stretching technique yield consistent velocity changes. In terms of stability, it is challenging to determine which technique performs better, due to differences in the mechanisms triggering cycle skipping. However, when considering waves with frequencies ranging from 50 kHz to 80 kHz, both techniques exhibit comparable performance. Based on our findings, we offer the following recommendations for utilizing these CWI techniques in concrete stress monitoring: For the stretching technique, selecting the time window length based on the wave frequency and the expected magnitude of velocity change. For the WCS technique, operating it in the frequency band where spectral decomposition shows sufficiently high energy in the signal and can accommodate the expected magnitude of velocity change.Concrete StructuresApplied Geophysics and Petrophysic
[[alternative]]The Study of Spectators’ Identification of the sponsors in Taiwan High School Games of 2002
[[abstract]]The purpose of the study was to assess the spectators’ identification of the sponsors in Taiwan High School Games of 2002. Subjects, 1230 volunteer spectators, were asked to respond to a self-made questionnaire, The data was analyzed by descriptive Statistics, t-test , ANOVA and Pearson Correlation. The study found:
1.Among the sponsors, Far East Department Store was ecognized by the Spectators the most, while Cheng Loong corp the least.
2.There was no correlation between spectators’ sex and marriage status with their identification of the sponsors.
3.The spectators’ age correlated with their impression of a corporate image, their willingness to buy a product and their liking for a brand.
4.The spectators’ occupation, educational background and monthly income had a positive correlation with their identification of the sponsors.
5.Spectators’ experiences of different activities correlated with their impression of a corporate image , their willingness to buy a product and their liking for a brand.
Key words:sponsorship of corporations,the spectators’ identification of the sponsors,sponsors.
[[alternative]]Studies on anisotropic wet etching characteristics of single crystal silicon under high pressure and high temperature conditions
[[abstract]]Anisotropic wet etching is one of the key technologys for the microstructure fabrication in Micro Electro Mechanical Systems(MEMS). In the study, for improving the roughness quality and etching rate of etched surface, high pressure and high temperature enhanced fast anisotropic etching of mono-crystalline silicon, the methods will be used to evaluate the etching properties of (100) silicon plane in KOH or TMAH solutions. The anisotropic etching parameters will be optimized adequately and employed to fabricate the high precise silicon microstructures.
For the study of batch production, the silicon structures will be formed the metallic mold insert by the electroforming process, and then the molding process, including hot embossing or injection molding, will be applied to produce mass plastic microstructure, and then the low-cost MEMS applications will be realized. Four key techniques will be focused as followed: (1) To setup the apparatus of high pressure and high temperature suitable to anisotropic fast wet etching of single silicon; (2) To build up the optimized fast etching process parameters, (3) To fabricatie the silicon-microstructure and Silicon nitride membrane microstructure.
The results of carrying out project will be predicted to promote the domestic silicon etching technique in MEMS , and also facilitate the international competitive power of the related companies in the market of micro-systems, which have been demonstrated as the highest valued industry in the future.
The C1 wedge connection in towers for wind turbine structures, tensile behaviour of a segment test
This paper shows a part of the analysis of the development of the second generation of the C1 wedge connections for use in offshore wind turbine supporting towers. The novelty of this connection is that bolt failure is avoided under static and fatigue loads. This study aims to investigate the tensile behaviour of the connection by combining the findings of experiments and finite element (FE) analysis. Two specimens subjected to uniaxial and cyclic tensile loading tested until failure are used for illustration. Advanced quasi-static FE analysis results, considering the most detailed geometry and using an explicit dynamic solver, are compared to the experimental results. The FE analysis results agree well with the experimental results. Based on the FE model, a parametric study is carried out to analyse the influence of the bolt grade, friction coefficient between contact surfaces, and preloading force level on mechanical behaviour. Failure modes, bolt force development, and the evolution of gap opening between contacted segments are analysed. Results demonstrate that the tensile fracture of the C1 wedge connection mainly appears in the lower segment. All the investigated parameters have a negligible effect on the connection's ultimate resistance and failure mode. However, the friction coefficient between contact surfaces and bolt preload level significantly affects the connection's local deformation capacity and the response of the bolt stress range. The FE simulation provides practical guidance for designing this connection without bolt failure.Steel & Composite Structure
Improved Wordpcfg for Passwords with Maximum Probability Segmentation
Modeling password distributions is a fundamental problem in password security, benefiting the research and applications on password guessing, password strength meters, honey password vaults, etc. As one of the best segment-based password models, WordPCFG has been proposed to capture individual semantic segments (called words) in passwords. However, we find WordPCFG does not address well the ambiguity of password segmentation by maximum matching, leading to the unreasonable segmentation of many password and further the inaccuracy of modeling password distributions. To address the ambiguity, we improve WordPCFG by maximum probability segmentation with A*-like pruning algorithm. The experimental results show that the improved WordPCFG cracks 99.26%–99.95% passwords, with nearly 5.67%–18.01% improvement.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Cyber Securit
Analysis and Visualization of Research on Resilient Cities and Communities Based on VOSviewer
To objectively grasp the current situation and development trend of resilient cities or communities (RC) research. The articles in Web of Science (WOS) Core Collection databases from 1995 to 2022 were used as a sample, and bibliometrics was used to statistically analyze the year of publication and number of articles, highly cited documents and keyword hotness in this field. VOSviewer was used to explore the knowledge graph of RC research documents. The results show that: the development process is roughly divided into 3 periods: no attention (1995–2004), starting (2005–2014), and rapid growth (2015–2021). The journal “Sustainability” and “International journal of disaster risk reduction” are the key journals publishing RC research. Serre and Shaw are the most productive authors. The USA is still the leading country in this field of RC. Colorado State Univ, Texas a&m Univ, and Delft Univ Technol are the main research institutions. The keyword analysis indicates the hot topics in different periods. Moreover, several limitations and some recommendations for future research on RC are also given based on this.Safety and Security Scienc
Analysis of Injury Severity of Drivers Involved Different Types of Two-Vehicle Crashes Using Random-Parameters Logit Models with Heterogeneity in Means and Variances
This study proposes random-parameters multinomial logit models, with heterogeneity in means and variances, to explore the differences in the factors influencing injury severities of drivers involved in different types of two-vehicle crashes. The models are verified using crash data from the United Kingdom (UK) over three years (2016–2018). Three types of crashes are separately identified (car-car, car-truck, and truck-truck crashes). In this study, a wide variety of potential variables, including the driver, vehicle, road, and environmental characteristics, are considered, with two possible injury-severity outcomes: severe and slight injury. The results show that unobserved heterogeneity existed for young drivers in both car-car and truck-truck crash models and the 30 mph speed limit in the three separate models. Remarkably variations are observed in crashes involving different types of vehicles. The driver’s age and gender, speeding, sideswipes, presence of junctions, weekdays, unlit, and weather conditions significantly impact driver-injury severities in various types of vehicle crashes. These findings are expected to help policymakers seek to improve highway safety and implement proper safety countermeasures.Transport and Plannin
Evaluation of the fatigue properties for the long-term service asphalt pavement using the semi-circular bending tests and stereo digital image correlation technique
Reliable assessment of the fatigue resistance of asphalt pavement with a long-term service is critically crucial for the rational formulation of original pavement utilization strategies in reconstruction and expansion projects. Currently, the pavement performance evaluation indicators are mainly used to guide pavement preventive maintenance, and its applicability in reconstruction and expansion projects of the freeway is limited. This paper aims to propose an evaluation method of fatigue resistance of asphalt concrete utilizing semi-circular bending (SCB) tests and stereo digital image correlation (stereo-DIC) techniques. A total of 27 asphalt concrete cores were drilled from the three freeways (K84, K124, and K165) with a service life of more than 20 years, and the SCB specimens were produced to conduct the SCB fracture and fatigue tests. During the SCB test, the stereo-DIC technique was employed to monitor the evolution process of the strain distribution and crack length for the specimens. K-dimension tree neighbor-searching algorithm (K-d tree algorithm) was used to effectively measure the change of crack length corresponding to each fatigue load cycle. Meanwhile, the strain threshold of asphalt concrete crack initiation was determined by the bilinear softening cohesive zone model (CZM) to ensure the accuracy of the crack length calculated by the K-d tree algorithm. Furthermore, the relationship between crack growth rate and stress intensity, which was used to fit the Paris law parameters, was determined. The CZM and DIC results indicated that the strain threshold of asphalt concrete crack should be set as 2000 με when using the K-d tree algorithm to determine the crack length. With the stress ratio increase, the Paris law parameter A increased wavily, and the parameter n decreased steadily, while the threshold of the stress intensity factor increased steadily. The Paris law master curves could characterize the fatigue performance of various road sections at a wide load range. The residual fatigue life of K84, K124, K165 the road sections were 2.13E + 08, 3.57E + 08, and 1.02E + 07, respectively.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Pavement Engineerin