Controlling bridge vibrations using a viscoelastic waveguide absorber

The study aims to mitigate the impact of structure-borne noise from existing elevated railway bridges on residents living along the line. In the study, a viscoelastic waveguide absorber mounted on a track slab was proposed based on waveguide vibration absorption techniques by proceeding from the vibration transmitting path and using the track slab as the carrier. First, a dynamic model for the slab-mounted viscoelastic waveguide absorber was constructed, in which a vibration equation was derived and an energy consumption mechanism was obtained. Then, a Chinese railway track style II (CRTS II) ballastless track slab most widely used in Chinese elevated railways was modelled as the primary vibration system, on which an experimental modal analysis was performed. Additionally, a parameterized analysis was performed on the dynamic performance of the slab-mounted viscoelastic waveguide absorber based on the vibration absorption and energy consumption mechanism of the absorber to determine the optimum parameter configuration for the dissipater. Furthermore, the most suitable installation positions for the energy waveguide links were defined using a response surface method. Finally, a bridge vibration response control effectiveness under train loads was also investigated, and it indicated that the waveguide absorbers had a favourable effect in reducing the vibration and structure-borne noise from the elevated railway bridge.

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Experimental Evaluation of the Packet Reception Performance of LoRa

Sensors ◽

10.3390/s21041071 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1071

Author(s):

Qingjie Guo ◽

Fengxu Yang ◽

Jianming Wei

Keyword(s):

Energy Consumption ◽

Optimal Parameter ◽

Signal To Noise Ratio ◽

Physical Layer ◽

Transmission Scheme ◽

Communication Time ◽

Parameter Configuration ◽

Packet Length ◽

The Impact ◽

The Relationship

LoRa technology is currently one of the most popular Internet of Things (IoT) technologies. A substantial number of LoRa devices have been applied in a wide variety of real-world scenarios, and developers can adjust the packet reception performance of LoRa through physical layer parameter configuration to meet the requirements. However, since the important details of the relationship between the physical layer parameters and the packet reception performance of LoRa remain unknown, it is a challenge to choose the appropriate parameter configuration to meet the requirements of the scenarios. Moreover, with the increase in application scenarios, the requirements for energy consumption become increasingly high. Therefore, it is also a challenge to know how to configure the parameters to maximize the energy efficiency while maintaining a high data rate. In this work, a complex evaluation experiment on the communication capability under a negative Signal to Noise Ratio is presented, and the specific details of the relationship between physical layer parameters and the packet reception performance of LoRa are clarified. Furthermore, we study the impact of the packet length on the packet reception performance of LoRa, and the experimental results show that when there is a large amount of data to be transmitted, it is better to choose long packets instead of short packets. Finally, considering the influence of physical layer parameters and the packet length on the packet reception performance of LoRa, the optimal parameter combination is explored, so as to propose a transmission scheme with a balanced reliability, delay, and energy consumption. This scheme is the first to consider the physical layer parameters and packet length together to study the communication transmission scheme, which reduces the communication time by 50% compared with the traditional transmission scheme and greatly reduces the energy consumption.

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Influence of bridge-based designed TMD on running trains

Journal of Vibration and Control ◽

10.1177/1077546318773022 ◽

2018 ◽

Vol 25 (1) ◽

pp. 182-193 ◽

Cited By ~ 11

Author(s):

Zhaowei Chen ◽

Hui Fang ◽

Zhaoling Han ◽

Shizheng Sun

Keyword(s):

Design Methodology ◽

Dynamic Performance ◽

Engineering Problem ◽

Bridge Engineering ◽

Bridge Structure ◽

Railway Bridges ◽

Earthquake Loads ◽

Practical Engineering ◽

Track Bridge ◽

Bridge Vibrations

A tuned mass damper (TMD) is a widely used vibration reduction measure in bridge engineering, whose design is based on the modal property of bridge structure. As a consequence, bridge vibrations in certain frequencies are reduced, while vibrations in some other frequencies may be amplified according to the design methodology of the TMD. This paper systematically investigates the influence of these amplified frequencies on the dynamic performance of running trains subject to earthquake loads. Primarily, the design methodology of bridge-based designed TMD (BBD-TMD) is introduced. On this basis, a detailed train–track–bridge coupled dynamic model with attached BBD-TMD is established based on the multi-body dynamics theory and the finite element method. Finally, aiming at a practical engineering problem in China, the influence of BBD-TMD on running trains subject to earthquake loads is investigated. The results indicate that, for the bridge structure adopted in this study, the amplified frequency bands are similar to the natural frequencies of the car body in the train system. To design TMDs for railway bridges, the dynamic performance of running trains caused by these external installations should be seriously considered.

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Impact of roof shading on building energy performance in warm & humid climatic places of India

iCRBE Procedia ◽

10.32438/icrbe.202037 ◽

2020 ◽

pp. 50-64

Author(s):

Kuladeep Kumar Sadevi ◽

Avlokita Agrawal

Keyword(s):

Energy Consumption ◽

Energy Conservation ◽

Energy Performance ◽

General Assumption ◽

Climatic Conditions ◽

Building Envelope ◽

Passive Cooling ◽

Base Case ◽

U Value ◽

The Impact

With the rise in awareness of energy efficient buildings and adoption of mandatory energy conservation codes across the globe, significant change is being observed in the way the buildings are designed. With the launch of Energy Conservation Building Code (ECBC) in India, climate responsive designs and passive cooling techniques are being explored increasingly in building designs. Of all the building envelope components, roof surface has been identified as the most significant with respect to the heat gain due to the incident solar radiation on buildings, especially in tropical climatic conditions. Since ECBC specifies stringent U-Values for roof assembly, use of insulating materials is becoming popular. Along with insulation, the shading of the roof is also observed to be an important strategy for improving thermal performance of the building, especially in Warm and humid climatic conditions. This study intends to assess the impact of roof shading on building’s energy performance in comparison to that of exposed roof with insulation. A typical office building with specific geometry and schedules has been identified as base case model for this study. This building is simulated using energy modelling software ‘Design Builder’ with base case parameters as prescribed in ECBC. Further, the same building has been simulated parametrically adjusting the amount of roof insulation and roof shading simultaneously. The overall energy consumption and the envelope performance of the top floor are extracted for analysis. The results indicate that the roof shading is an effective passive cooling strategy for both naturally ventilated and air conditioned buildings in Warm and humid climates of India. It is also observed that a fully shaded roof outperforms the insulated roof as per ECBC prescription. Provision of shading over roof reduces the annual energy consumption of building in case of both insulated and uninsulated roofs. However, the impact is higher for uninsulated roofs (U-Value of 3.933 W/m2K), being 4.18% as compared to 0.59% for insulated roofs (U-Value of 0.33 W/m2K).While the general assumption is that roof insulation helps in reducing the energy consumption in tropical buildings, it is observed to be the other way when insulation is provided with roof shading. It is due to restricted heat loss during night.

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ANALISIS DETERMINAN KUALITAS LINGKUNGAN PERIODE 1999-2013

Jurnal Ekonomi dan Bisnis ◽

10.24123/jeb.v21i1.1632 ◽

2016 ◽

Vol 21 (1) ◽

pp. 9-20

Author(s):

Ersalina Tang

Keyword(s):

Foreign Direct Investment ◽

Energy Consumption ◽

Gross Domestic Product ◽

Co2 Emissions ◽

Direct Investment ◽

Meat Consumption ◽

Domestic Product ◽

World Data ◽

The World ◽

The Impact

The purpose of this study is to analyze the impact of Foreign Direct Investment, Gross Domestic Product, Energy Consumption, Electric Consumption, and Meat Consumption on CO2 emissions of 41 countries in the world using panel data from 1999 to 2013. After analyzing 41 countries in the world data, furthermore 17 countries in Asia was analyzed with the same period. This study utilized quantitative approach with Ordinary Least Square (OLS) regression method. The results of 41 countries in the world data indicates that Foreign Direct Investment, Gross Domestic Product, Energy Consumption, and Meat Consumption significantlyaffect Environmental Qualities which measured by CO2 emissions. Whilst the results of 17 countries in Asia data implies that Foreign Direct Investment, Energy Consumption, and Electric Consumption significantlyaffect Environmental Qualities. However, Gross Domestic Product and Meat Consumption does not affect Environmental Qualities.

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The Nexus between Financial Development, Economic Growth and Energy Consumption in India: A VECM Technique

Indian Journal of Economics and Development ◽

10.35716/ijed/20131 ◽

2020 ◽

pp. 602-612

Keyword(s):

Economic Growth ◽

Energy Consumption ◽

Financial Development ◽

Consumer Price Index ◽

Development Economic ◽

Energy Prices ◽

Vector Error Correction ◽

Percent Increase ◽

Growth Energy ◽

The Impact

The demand for energy consumption requires efficient financial development in terms of bank credit. Therefore, this study examines the nexus between Financial Development, Economic Growth, Energy Prices and Energy Consumption in India, utilizing Vector Error Correction Model (VECM) technique to determine the nature of short and long term relationships from 2010 to 2019. The estimation of results indicates that a one percent increase in bank credits to private sector results in 0.10 percent increase in energy consumption and 0.28 percent increase in energy consumption responses to 1 percent increase in economic growth. It is also observed that the impact of energy price proxied by consumer price index is statistically significant with a negative sign indicating the consistency with the theory.

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Empirical evidence on the impact of urban overheating on building cooling and heating energy consumption

iScience ◽

10.1016/j.isci.2021.102495 ◽

2021 ◽

pp. 102495

Author(s):

Mi Aye Su ◽

Jack Ngarambe ◽

Mat Santamouris ◽

Geun Young Yun

Keyword(s):

Energy Consumption ◽

Empirical Evidence ◽

Heating Energy Consumption ◽

Building Cooling ◽

The Impact

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Graphene-based 3D XNOR-VRRAM with ternary precision for neuromorphic computing

npj 2D Materials and Applications ◽

10.1038/s41699-021-00236-x ◽

2021 ◽

Vol 5 (1) ◽

Author(s):

Batyrbek Alimkhanuly ◽

Joon Sohn ◽

Ik-Joon Chang ◽

Seunghyun Lee

Keyword(s):

Neural Network ◽

Energy Consumption ◽

Recognition Accuracy ◽

Material Selection ◽

Weighted Sum ◽

Device Design ◽

Key Factors ◽

Neuromorphic Computing ◽

Device Scaling ◽

The Impact

AbstractRecent studies on neural network quantization have demonstrated a beneficial compromise between accuracy, computation rate, and architecture size. Implementing a 3D Vertical RRAM (VRRAM) array accompanied by device scaling may further improve such networks’ density and energy consumption. Individual device design, optimized interconnects, and careful material selection are key factors determining the overall computation performance. In this work, the impact of replacing conventional devices with microfabricated, graphene-based VRRAM is investigated for circuit and algorithmic levels. By exploiting a sub-nm thin 2D material, the VRRAM array demonstrates an improved read/write margins and read inaccuracy level for the weighted-sum procedure. Moreover, energy consumption is significantly reduced in array programming operations. Finally, an XNOR logic-inspired architecture designed to integrate 1-bit ternary precision synaptic weights into graphene-based VRRAM is introduced. Simulations on VRRAM with metal and graphene word-planes demonstrate 83.5 and 94.1% recognition accuracy, respectively, denoting the importance of material innovation in neuromorphic computing.

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Review on Urban Heat Island in China: Methods, Its Impact on Buildings Energy Demand and Mitigation Strategies

Sustainability ◽

10.3390/su13020762 ◽

2021 ◽

Vol 13 (2) ◽

pp. 762

Author(s):

Liu Tian ◽

Yongcai Li ◽

Jun Lu ◽

Jue Wang

Keyword(s):

Energy Consumption ◽

Urban Heat Island ◽

Building Energy ◽

Design Stage ◽

Heat Island ◽

Building Energy Consumption ◽

Rapid Urbanization ◽

Substantial Impact ◽

Urban Heat ◽

The Impact

High population density, dense high-rise buildings, and impervious pavements increase the vulnerability of cities, which aggravate the urban climate environment characterized by the urban heat island (UHI) effect. Cities in China provide unique information on the UHI phenomenon because they have experienced rapid urbanization and dramatic economic development, which have had a great influence on the climate in recent decades. This paper provides a review of recent research on the methods and impacts of UHI on building energy consumption, and the practical techniques that can be used to mitigate the adverse effects of UHI in China. The impact of UHI on building energy consumption depends largely on the local microclimate, the urban area features where the building is located, and the type and characteristics of the building. In the urban areas dominated by air conditioning, UHI could result in an approximately 10–16% increase in cooling energy consumption. Besides, the potential negative effects of UHI can be prevented from China in many ways, such as urban greening, cool material, water bodies, urban ventilation, etc. These strategies could have a substantial impact on the overall urban thermal environment if they can be used in the project design stage of urban planning and implemented on a large scale. Therefore, this study is useful to deepen the understanding of the physical mechanisms of UHI and provide practical approaches to fight the UHI for the urban planners, public health officials, and city decision-makers in China.

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Economic Development, CO2 Emissions and Energy Use Nexus-Evidence from the Danube Region Countries

Energies ◽

10.3390/en14113165 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3165

Author(s):

Eva Litavcová ◽

Jana Chovancová

Keyword(s):

Economic Growth ◽

Energy Consumption ◽

Co2 Emissions ◽

Carbon Emissions ◽

Bounds Testing ◽

Mutual Cooperation ◽

Long Run ◽

Short Run ◽

Danube Region ◽

The Impact

The aim of this study is to examine the empirical cointegration, long-run and short-run dynamics and causal relationships between carbon emissions, energy consumption and economic growth in 14 Danube region countries over the period of 1990–2019. The autoregressive distributed lag (ARDL) bounds testing methodology was applied for each of the examined variables as a dependent variable. Limited by the length of the time series, we excluded two countries from the analysis and obtained valid results for the others for 26 of 36 ARDL models. The ARDL bounds reliably confirmed long-run cointegration between carbon emissions, energy consumption and economic growth in Austria, Czechia, Slovakia, and Slovenia. Economic growth and energy consumption have a significant impact on carbon emissions in the long-run in all of these four countries; in the short-run, the impact of economic growth is significant in Austria. Likewise, when examining cointegration between energy consumption, carbon emissions, and economic growth in the short-run, a significant contribution of CO2 emissions on energy consumptions for seven countries was found as a result of nine valid models. The results contribute to the information base essential for making responsible and informed decisions by policymakers and other stakeholders in individual countries. Moreover, they can serve as a platform for mutual cooperation and cohesion among countries in this region.

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