Experimental Study on Pedestrians' Perception of Human-Induced Vibrations of Footbridges

2018 ◽  
Vol 18 (10) ◽  
pp. 1850116 ◽  
Author(s):  
Rujin Ma ◽  
Lu Ke ◽  
Dalei Wang ◽  
Airong Chen ◽  
Zichao Pan
Keyword(s):  
Experimental Studies ◽  
Shaking Table ◽  
Key Factors ◽  
Crucial Issue ◽  
Lateral Vibrations ◽  
Acceleration Amplitude ◽  
Vibration Serviceability ◽  
People’S Perception ◽  
Two Factors ◽  
Comfort Criteria

Owing to the slenderness and lightness of most modern footbridges, vibration serviceability assessment becomes a crucial issue in the design process. As one of the key factors, the vibration comfort criterion has an important influence on the assessment of the final result. However, there is an obvious lack of experimental studies in this field, especially regarding the pedestrians' perception of the induced vibrations. In this study, an experiment was conducted to investigate the pedestrians' perception of human-induced vibrations of footbridges. During the experiment, the subjects walked on a pathway that was mounted on top of a shaking table. By imposing sinusoidal excitations with different amplitudes and frequencies, the experiment aimed to determine the influence of the two factors on the walking people's perception. Based on the data collected, perception scales were proposed for both the vertical and lateral vibrations of the footbridge. The established scales comprise five levels that depend on the acceleration amplitude and the frequency. Finally, a comparison between the proposed scales, existing comfort criteria in the literature and international codes was carried out.

Experimental Studies on a Mineral Containing Titanium in Baoding Area

2013 ◽  
Vol 826 ◽  
pp. 34-37 ◽  
Author(s):  
Guo Zhen Liu ◽  
Shu Juan Dai ◽  
Li Mei Bai ◽  
Yu Xin Ma ◽  
Yong Zhang
Keyword(s):  
Magnetic Separation ◽  
High Intensity ◽  
Ph Value ◽  
Experimental Studies ◽  
Mineral Processing ◽  
Shaking Table ◽  
Gravity Concentration

The main elements can be recovered for mineral processing in a mineral containing titanium of Baoding area were Ti, Fe and V, and the elements in the main gangue minerals were Si and Al. Gravity concentration, gravity concentration-high intensity magnetic separation and gravity concentration-flotation tests were performed on the ore sample respectively. The results showed that, in the test of shaking table, when the grinding fineness was -0.074mm 93%, the productivity of concentrate can reach 32.24%; when grinding fineness was -0.074mm 93%, after gravity concentration-magnetic separation, 30.25% of concentrate productivity can be attained; when the grinding fineness was -0.074mm 85%, after gravity concentration-flotation, the productivity of concentrate was 3.31%. Maybe it's the condition of the tests wasn't controlled well, especially adjusting pH value in the flotation stage, it's hard to control, so the results were not very good.

scholarly journals Using a Novel Grey DANP Model to Identify Interactions between Manufacturing and Logistics Industries in China

2018 ◽  
Vol 10 (10) ◽  
pp. 3456 ◽  
Author(s):  
Peng Jiang ◽  
Yi-Chung Hu ◽  
Ghi-Feng Yen ◽  
Hang Jiang ◽  
Yu-Jing Chiu
Keyword(s):  
Manufacturing Industry ◽  
Multiple Criteria Decision Making ◽  
Value Added ◽  
Manufacturing Industries ◽  
Direct Influence ◽  
Key Factors ◽  
Logistics Industry ◽  
Influence Matrix ◽  
Factors Affecting ◽  
Two Factors

As a crucial part of producer services, the logistics industry is highly dependent on the manufacturing industry. In general, the interactive development of the logistics and manufacturing industries is essential. Due to the existence of a certain degree of interdependence between any two factors, interaction between the two industries has produced a basis for measurement; identifying the key factors affecting the interaction between the manufacturing and logistics industries is a kind of decision problem in the field of multiple criteria decision making (MCDM). A hybrid MCDM method, DEMATEL-based ANP (DANP) is appropriate to solve this problem. However, DANP uses a direct influence matrix, which involves pairwise comparisons that may be more or less influenced by the respondents. Therefore, we propose a decision model, Grey DANP, which can automatically generate the direct influence matrix. Statistical data for the logistics and manufacturing industries in the China Statistical Yearbook (2006–2015) were used to identify the key factors for interaction between these two industries. The results showed that the key logistics criteria for interaction development are the total number of employees in the transport business, the volume of goods, and the total length of routes. The key manufacturing criteria for interaction development are the gross domestic product and the value added. Therefore, stakeholders should increase the number of employees in the transport industry and freight volumes. Also, the investment in infrastructure should be increased.

Airborne Infection Isolation Rooms – A Review of Experimental Studies

2011 ◽  
Vol 20 (6) ◽  
pp. 584-594 ◽  
Author(s):  
Marko Hyttinen ◽  
Anna Rautio ◽  
Pertti Pasanen ◽  
Tiina Reponen ◽  
G. Scott Earnest ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Experimental Studies ◽  
Air Leakage ◽  
Crucial Issue ◽  
Actual Knowledge ◽  
Airborne Infection ◽  
The Us ◽  
Air Cleaners ◽  
Long Time ◽  
Save Energy

Ventilation guidelines for airborne infection isolation rooms (AIIRs) are highly variable in different countries indicating lack of actual knowledge about the guidance needed. However, US guidelines for AIIRs are extensive and have been widely adopted outside the US. AIIR performance has also been evaluated in numerous studies. For a long time, the aim has mainly been to evaluate how well the existing AIIRs meet US guidelines. For historical reasons, mixing-type ventilation has been emphasised and attention has been paid to air exchange rates, although the use of auxiliary devices, such as portable room-air cleaners and ultraviolet germicidal irradiation systems, has also been examined. Recently, the scope of the investigations has been widened. The most crucial issue is to minimise the potential for disease transmission and prevent the escape of contaminated air from the AIIR. Airflow direction inside the AIIR is also important and AIIRs minimise air leakage to save energy. On the other hand, it has been observed that efficient containment can be achieved even by using simple and inexpensive construction by considering pressure differential and air flow patterns. Nevertheless, additional research is needed to assist hospitals with improving their preparedness to cope with the threat of pandemics by building and using effective AIIRs.

Uncertainty Is Inherent in Science

Uncertainty ◽  
2019 ◽  
pp. 149-165
Author(s):  
Kostas Kampourakis ◽  
Kevin McCain
Keyword(s):  
Nature Of Science ◽  
Climate Science ◽  
Natural Phenomena ◽  
Key Factors ◽  
Scientific Methods ◽  
Absolute Certainty ◽  
Two Factors

At times people seem to have a mythical view of science as an infallible source of absolute certainty. Despite the prevalence of such a view, it is deeply misguided. All science is inherently uncertain. Two key factors that contribute to science’s inherent uncertainty are the complexity of natural phenomena and human limitations. Although the challenges posed by these two factors can be somewhat mitigated by way of scientific methods of investigation and the use of precise mathematical formulations, neither can be fully done away with. As a result, all science, no matter how precise or careful the methods it employs, is inherently uncertain. This is important to realize not only for truly understanding the nature of science, but also for appreciating that pointing out uncertainties that exist in domains like climate science, evolution, and vaccination in no way undercuts their claims to being legitimate, trustworthy science.

scholarly journals Surface-Related Features Responsible for Cytotoxic Behavior of MXenes Layered Materials Predicted with Machine Learning Approach

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3083
Author(s):  
Maciej E. Marchwiany ◽  
Magdalena Birowska ◽  
Mariusz Popielski ◽  
Jacek A. Majewski ◽  
Agnieszka M. Jastrzębska
Keyword(s):  
Machine Learning ◽  
Transition Metal Oxides ◽  
2D Materials ◽  
Experimental Studies ◽  
Biological Data ◽  
Data Sets ◽  
Toxicological Studies ◽  
Two Factors ◽  
Health Need

To speed up the implementation of the two-dimensional materials in the development of potential biomedical applications, the toxicological aspects toward human health need to be addressed. Due to time-consuming and expensive analysis, only part of the continuously expanding family of 2D materials can be tested in vitro. The machine learning methods can be used—by extracting new insights from available biological data sets, and provide further guidance for experimental studies. This study identifies the most relevant highly surface-specific features that might be responsible for cytotoxic behavior of 2D materials, especially MXenes. In particular, two factors, namely, the presence of transition metal oxides and lithium atoms on the surface, are identified as cytotoxicity-generating features. The developed machine learning model succeeds in predicting toxicity for other 2D MXenes, previously not tested in vitro, and hence, is able to complement the existing knowledge coming from in vitro studies. Thus, we claim that it might be one of the solutions for reducing the number of toxicological studies needed, and allows for minimizing failures in future biological applications.

scholarly journals Flow structure around an actual willow patch under different depth conditions

2018 ◽  
Vol 40 ◽  
pp. 02049
Author(s):  
Chanjoo Lee ◽  
Donggu Kim ◽  
Sungjung Kim ◽  
Un Ji ◽  
Jihyun Kim ◽  
...  
Keyword(s):  
Flow Measurement ◽  
Flash Flood ◽  
Experimental Studies ◽  
Hydrodynamic Modelling ◽  
Snow Melt ◽  
Key Factors ◽  
Environmental Aspects ◽  
Real Scale ◽  
Natural Channel ◽  
Made In

Vegetation is one of the key factors in river management where environmental aspects as well as flood protection should be taken into consideration. Because of this, numerous studies have been done including experiments and hydrodynamic modelling. Because most of experimental studies were made in indoor laboratory flumes with artificial trees, there are still limitations in transfer of their result to actual channels. REC (River Experiment Center) of Korea has been operating three real-scale, nature-like outdoor experimental channels. In a straight channel, several 4x2 m actual willow patches were planted and have been grown last three years for studies on flow vegetation interaction. A set of intensive flow measurement was made around the first upstream willow patch using ADVs together with measurement of vegetation properties. The experiments were made under several different depth conditions simulating snow-melt and flash-flood. Distribution of flow around and through the patch was characterized along with vertical profiles. The results of the experiment enhance understanding on interaction of flow and actual vegetation in a natural channel and may also provide information on flow resistance used for hydrodynamic modelling and validation.

Experimental studies of a typical sprinkler piping system in hospitals

2016 ◽  
Vol 49 (1) ◽  
pp. 1-12
Author(s):  
Zhen-Yu Lin ◽  
Fan-Ru Lin ◽  
Juin-Fu Chai ◽  
Kuo-Chun Chang
Keyword(s):  
Failure Modes ◽  
Experimental Studies ◽  
Hysteresis Loops ◽  
Research Programme ◽  
Shaking Table ◽  
Piping System ◽  
Improvement Strategy ◽  
Flexible Pipes ◽  
Piping Systems ◽  
Cyclic Loading Tests

Based on the issue of life safety and immediate needs of emergency medical services provided by hospitals after strong earthquakes, this paper aims to introduce a research programme on assessment and improvement strategies for a typical configuration of sprinkler piping systems in hospitals. The study involved component tests and subsystem tests. Cyclic loading tests were conducted to investigate the inelastic behaviour of components including concrete anchorages, screwed fittings of small-bore pipes and couplings. Parts of a horizontal piping system of a seismic damaged sprinkler piping system were tested using shaking table tests. Furthermore, horizontal piping subsystems with seismic resistant devices such as braces, flexible pipes and couplings were also tested. The test results showed that the main cause of damage was the poor capacity of a screwed fitting of the small-bore tee branch. The optimum improvement strategy to achieve a higher nonstructural performance level for the horizontal piping subsystem is to strengthen the main pipe with braces and decrease moment demands on the tee branch by the use of flexible pipes. The hysteresis loops and failure modes of components were further discussed and will be used to conduct numerical analysis of sprinkler piping systems in future studies.

Characteristics of UV Irradiated Waste Biopolymer from Renewable Resources (Part 1)

2014 ◽  
Vol 974 ◽  
pp. 252-256 ◽  
Author(s):  
Shaiqah Mohd Rus ◽  
Najibah Abd. Latif ◽  
Mohd Imran Ghazali ◽  
Anika Zafiah M. Rus
Keyword(s):  
Developed Countries ◽  
Waste Cooking Oil ◽  
Shaking Table ◽  
Cooking Oil ◽  
Testing Frequency ◽  
Acceleration Amplitude ◽  
Before And After ◽  
Vibration Transmissibility ◽  
The Developed Countries ◽  
Photo Stability

Waste cooking oil has proven to be a problematic material in the developed countries since people usually pour waste cooking oil into the kitchen drainage because they unaware that this waste can be recycled. Thus, in this study, the converted waste cooking oil into polymer was fabricated by using hot compression machine and named as waste biopolymer (WB). Vibration transmissibility test was conducted to determine the WB characteristics before and after UV-irradiated. It is revealed the similar vibration transmissibility responses curves were obtained at 1mm, 0.1g and 0.15g base excitation levels for the entire testing frequency except for the displacement transmissibility from base to moveable top plate at 1.5 mm. There was only one resonance peak occurred over the testing frequency which was 15 - 23 Hz for the displacement transmissibility and 15 – 25 Hz for the acceleration transmissibility test on shaking table. No other variation used on the displacement and acceleration amplitude to control the transmissibility test of UV-irradiated WB system based on shaking table. Evidently, small changes on the frequency of the vibration transmissibility were shifted to higher value of UV-irradiated WB with overall percentages of changes are below 5% except for displacement transmissibility at 1.5 mm. This shows the photo-stability of WB after UV-irradiation is high and could be used for further study.

Investigation on Seismic Behavior of Recycled Aggregate Concrete Structures under Dynamic Loadings

2013 ◽  
Vol 772 ◽  
pp. 149-155
Author(s):  
Chang Qing Wang
Keyword(s):  
Seismic Behavior ◽  
Fatigue Behavior ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Recycled Aggregate Concrete ◽  
Shaking Table ◽  
Frame Structure ◽  
Recycled Aggregate ◽  
Scale Model ◽  
Aggregate Concrete

Based on the ever finished investigations of physical and mechanical properties of recycled aggregate concrete (RAC), and a series of experimental studies on the durability, the fatigue behavior, mechanical behavior and the seismic behavior of RAC components. A full scale model of a one-storey block masonry structure with tie column + ring beam + cast-in-place slab system and a one fourth scaled model of a 6-storey frame structure, which are made of reinforced recycled aggregate concrete, are tested on a shaking table by subjecting it to a series of simulated seismic ground motions, and the seismic behaviors of the RAC structures were experimentally investigated. The dynamic characteristics and the seismic response were analyzed and discussed. The overall seismic performance of RCA structures are evaluated, the analysis results show that the recycled aggregate concrete structures with proper design exhibits good seismic behavior and can resist the earthquake attacks under different earthquake levels in this study. It is feasible to apply and popularize the RAC block masonry buildings less than 2 stories and the RAC frame buildings less than 6 stories in the region where the seismic fortification intensity is 8.

Theoretical and Experimental Studies on Reduction for Multi-Modal Seismic Responses of High-Rise Structures by Tuned Liquid Dampers

2004 ◽  
Vol 10 (7) ◽  
pp. 1041-1056 ◽  
Author(s):  
Hong-Nan Li ◽  
Ying Jia ◽  
Su-Yan Wang
Keyword(s):  
Passive Control ◽  
Equations Of Motion ◽  
Experimental Studies ◽  
Tall Buildings ◽  
Shaking Table ◽  
Earthquake Ground Motion ◽  
Seismic Responses ◽  
High Rise ◽  
Tuned Liquid Dampers ◽  
Liquid Dampers

This paper focuses on the use of multiple tuned liquid dampers (TLDs) as passive control devices to reduce the multi-modal responses of tall buildings and high-rise structures to earthquake ground motion excitation. A model of a three-story building with one and two TLDs was installed on a shaking-table. The system was subjected to three earthquake time histories. Then, the mechanical models and the equations of motion for the systems of tall buildings and high-rise structures with TLDs are established. Here, the solution of the dynamic liquid pressure is based on the method of the volume of fluid and the seismic responses are obtained by use of the state equation. The comparisons show that theoretical results are generally in good agreement with experiments. It is observed that the approach presented in this paper has proved to be quite effective both in the numerical example and in the seismic simulating tests.

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