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Open Access
Research article
Recent Fire Safety Design of High-Rise Buildings
lizhuo song ,
jing zhu ,
shaotong liu ,
zijian qu
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Available online: 10-31-2022

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As urbanization picks up speed, row upon row of high-rise buildings spring up, and their structure is increasingly complex. In the meantime, fire poses a more and more serious problem to these buildings. This paper summarizes the recent development of high-rise buildings, and analyzes the main features of high-rise building fire from the angles of material design, structural design, etc. The technical development of heat preservation material greatly improves the security of exterior fire prevention system. Starting from the structure of the building itself, architects have carried out systematic and reasonable planning for smoke exhaust design, automatic alarm design, stair design, and so on. The fire safety of high-rise buildings could be improved in an all-round way, drawing on advanced technologies like fighting drones, robots and the Internet of things.

Open Access
Research article
Empowering Regional Development with Quadruple Helix Creative Industry Model
mohammad yusri ,
abdul r. cemda ,
sasmita siregar
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Available online: 10-31-2022

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This study examines how to support regional development with the quadruple helix creative industry model through descriptive qualitative analysis. The primary data were collected through observation, interviews, and FGDs (Focus Group Discussions) with academics, creative economy actors, community leaders, and government officials. The markets in Medan, North Sumatra, Indonesia were studied between October 2020 and October 2021. Purposive sampling technique was used to select informants, and snowball sampling approach was utilized to conduct the interviews. The findings revealed that the lack of roles in research and knowledge production by academic actors in Medan has increased the need for a network of academic actors to fill the gap; the government has not been able to play a role in providing funding support and incentives for business actors in creative industries, especially in creating innovations. The synergy between actors in the quadruple helix implementation has not been properly utilized, even in the case of the Medan City Government, which ought to be the main source of information in social media for the city's creative sector. Following up on these findings, the quadruple helix creative industry model was implemented as an innovation model to support the regional economy of the city of Medan.

Open Access
Research article
Vertical Market Integration and Behavioral Variations of Medium-Quality Rice Prices Before and During Covid-19
tomycho olviana ,
doppy roy nendissa ,
marthen robinson pellokila ,
mariana dinah charlota lerik ,
nikmatul khoiriyah
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Available online: 10-31-2022

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The Covid-19 pandemic has put pressure on the prices of food, particularly rice, a strategic commodity for trade across Indonesia. The traditional market and wholesalers face intense price competition for rice, which renders the market ineffective. This study proves the form of rice market integration in wholesalers and traditional markets, as well as the behavior of pricing both before and after the pandemic. The research data are the weekly and monthly prices from the Indonesian National Strategic Food Price Information Center Institute for the years 2018 to 2021. Vector autoregression (VAR) and error correction model (ECM) were adopted for the integration analysis. The results suggest that prices in traditional markets and wholesalers cointegrate, but this does not persist over time. Equilibrium prices in both markets were reached after 4 months. The price trend demonstrates that price changes in both markets before and during the epidemic are not symmetric. Price changes during the Covid-19 epidemic were erratic and dramatic. Government involvement through suitable policies is required in a market environment under intense pressure to stabilize prices. Market participants must accept this policy in order to prevent any party from gaining an undue advantage.

Open Access
Research article
A Data Driven Approach to Measure Evolution Trends of City Information Modeling
guangdong wu ,
handong tang ,
yichuan deng ,
hengqin wu ,
chaoran lin
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Available online: 10-31-2022

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This work aims to reveal the current status of the city information modeling (CIM) from massive patent data, using the latent Dirichlet allocation (LDA) model, and quantify the evolution trends of future topics by the Hidden Markov Model (HMM). The results show that the CIM technologies can be divided into 17 topics. At the present stage, the technologies related to the Internet of things (IOT), big data and data management are the focus of the research and development (R&D) of CIM patents. Compared with the software technology, further development is needed for the hardware technology supporting CIM, particularly in terms of information acquisition (cameras and sensors), storage, and information transmitters. This study deepens the understanding of the CIM-related technical categories, and clarifies the direction of the development and evolution of CIM technology, providing a strong support to decision-makers in urban management.

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This paper assesses the potential of multiplicity in the housing environment for achieving social sustainability compared to singularity. For this purpose, a neighborhood assessment framework was developed to cover three values of social sustainability, namely, stability, continuity, and fairness, as well as several factors related to each value. Two cases were chosen from the neighborhoods in the city of Nablus: Type (1) as an example of multiplicity, and type (2) as an example of singularity. The research data were collected through an architectural survey on the features of both types of neighborhoods, and analyzed in details. On this basis, the two types of neighborhoods were compared based on the said values. The results show that the values of sustainability increase in type (2) at the level of the single building, while growing in type (1) at the level of the residential neighborhood. Multiplicity is a high-potential approach for achieving social sustainability, if the design of the residential buildings caters to people’s needs and wants. In addition, several suggestions were made for improving the neighborhood design in Palestine based on multiplicity.

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Although many fluidized systems are not vertically oriented, little research has been done on fluidization within inclined channels. The fluidization of the gravitational force and the tensile force may be substantially opposing in the vertical system. The theory of gravitational field fluidization, which is related to industrial fluidization processes like coal gasification, iron ore reduction, and catalytic cracking and calls for the use of standing tubes or angled risers, has to be developed in order to encompass various orientations. Without underlying theories, engineers must rely on vertical fluidization equations to build these sloping systems. A significant barrier to improving the design and optimization of new solid circulation systems is the tendency of fluidization. Based on historical developments and theoretical progress, the study presents an overview of recent advancements of liquid-solid fluidized beds in inclined columns. The fluidized bed is investigated as a whole by looking at the governing factors.

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This paper intends to improve the hydrogen production efficiency of the electrolysis cells, fully utilize wind energy, and ensure the reliability of power supply. For this purpose, the authors put forward a capacity optimization configuration for non-grid-connected wind-hydrogen hybrid energy storage system, in view of the features of hydrogen production efficiency. The working interval of the electrolytic cell was optimized by analyzing the said features. Considering the features of battery charge/discharge, equipment capacity and power, the authors formulated the energy management strategy applicable to six working conditions, established the quantitative multi-objective function of system cost and reliability, and solved the optimization model by the fast non-dominant sorting genetic algorithm (NSGA)-II. In this way, the optimal combination of energy storage capacity was determined. Next, the wind velocity data of a pastoral area in Inner Mongolia was measured, and analyzed in details. The analysis results show that the electrolytic cell always operates in the optimal working area, and the optimized wind-hydrogen system is economic and reliable in power supply. The research provides a reference for practical engineering applications.

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During the operation of the ground source heat pump (GSHP) system, the operations of the chiller system should be controlled by adjusting the difference between water temperature and wet bulb temperature. Therefore, it is important to consider the control strategy for the switch time (ST) and wet bulb temperature difference (WBTD) of the chiller system. This paper sets up two control strategies, namely, the strategy to control the ST of system operations, and the strategy to control the WBTD. Then, theoretical modeling was carried out to compare the system energy consumption and borehole wall temperature under different strategies. The modeling results were referred to optimize the control strategy for composite GSHP systems. It was found that, under the ST control strategy, the best wet bulb temperature is 2℃, and the best chiller operation hours are 3h; under the WBTD control strategy, the best wet bulb temperature is 3.5℃, and the best WBTD is 1.5℃. In addition, the ST control strategy is superior to the WBTD control strategy, in terms of system energy consumption, borehole wall temperature and initial investment.

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This study aims to realize continuous, high efficiency defrosting of air-to-air heat pumps using the effect of outdoor warm air recycling, trying to improve the coefficient of performance (COP) and total heat capacity of traditional defrosting methods like hot bypass and Joule heating. The proposed patented method recovers heat from the air change system by mixing the warm discarded air with the incoming air of the external heat exchanger. The fan of the external unit sucks the indoor air with the depression obtained by a Venturi. The warm air is ducted to the Venturi through a hole in the wall. The amount of warm air mixed to the outside air is regulated by a butterfly valve installed on the pipe from the hole to the Venturi. In this way, the air entering the external coil is warm enough to avoid frost. The energy efficiency of the system is assured, for the warm indoor air is heated with the high COP of the heat pump. Our system can achieve defrosting with a limited amount of warm air, and realize a higher overall COP than the best traditional defrosting systems. Finally, the defrosting device can be added as an option to any existing split systems.

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Bilinear and bicubic interpolations were often used in digital elevation models (DEMs), image scaling, and image restoration, with the aid of spatial transform techniques. This paper resorts to bilinear and bicubic interpolations, along with the spatial transform of images, to present the temperature distribution on a plate with a circular hole. The Dirichlet boundary conditions were applied, a rectangular grid was created, and the nodal values were calculated using the finite difference method (FDM). These methods were also employed to represent the mechanical stress distribution on a plate with a circular hole, under the presence of uniaxial stress. In this case, the nodal values were calculated using the analytical method. Experimental results show that bicubic interpolation generated continuous contours, while bilinear interpolation had a discontinuity in some cases. The results were comparative to images for similar cases when solved through ANSYS.

Open Access
Research article
Measuring Temperatures Generated by Air Plasma Technology
cristiano fragassa ,
marco arru ,
filippo capelli ,
ana pavlovic ,
matteo gherardi
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Available online: 10-30-2022

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The atmospheric pressure air plasma technology is based on the general principle of transforming the air into an ideal conductor of plasma energy thanks to the application of an electric potential difference able to ionize the molecules. Applying the principle to the human surgery, it comes to be possible to assure an energy transfer from plasma-generator devices to the human tissue in a relatively simple way: passing through the air, with exceptionally limited effects in terms of tissue heating. Such a condition is very useful to assure effective treatments in surgery: less thermal damage, fewer side effects on the patient. This is also what emerged during the use of innovative devices embedding the Airplasma® technology (by Otech Industry S.r.l.), where temperatures on human tissues were measured stably below 50°C. However, the profiles assumed by the temperature along the different electrodes during the operating conditions are rather unclear. This knowledge is essential to improve the efficiency of the electrodes (through their redesign in shapes and materials) as well as to reduce the invasiveness of surgical interventions. The present work had the purpose of characterizing the most common electrodes thanks to temperature measurements carried out by infrared sensors respect to different operating conditions. A simplified finite element model was also developed to support the optimal redesign of electrodes.

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Given the geometric nonlinearity of the piezoelectric cantilever beam, this study establishes a distributed parameter model of the nonlinear bi-stable cantilever piezoelectric energy harvester, following the generalized Hamilton variational principle. The analytical expressions of the dynamic response were obtained for the energy harvesting system using Galerkin modal decomposition and the multi-scale method. The investigation focuses on how the performance of the energy harvesting system is influenced by the gap distance between magnets, external excited amplitude, mechanical damping ratio and external load resistance. The calculation results were compared with those obtained neglecting the geometric nonlinearity of the beam. The results show that the system responses contain jump and multiple solutions. The consideration of the geometrical nonlinearity significantly amplified the peak displacement and peak output power of the intra-well and inter-well motions. There is an evident hardening effect of the inter-well motion frequency response curve. By reasonable adjusting the parameters, it is possible to improve the output power of the piezoelectric energy harvesting system and broaden the operating frequency of the system.

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The overhead crane is a typical underactuated system with complicated dynamics and strong couplings. It is widely employed to transport heavy cargoes in many industrial fields. Due to the complexity of working environments, however, cranes often encounter various unfavorable factors, which may degrade the transportation efficiency. To enhance control performance and anti-disturbance ability, this paper proposes an active disturbance rejection control approach based on differential flatness for double pendulum cranes with variable rope lengths. The proposed approach can position the trolley accurately, regulate rope length, and suppress the swing angles of the payload and the hook simultaneously. During the controller design, flat outputs were constructed based on differential flatness technique to deal with system couplings, and the results prove that double pendulum crane system is differentially flat. After that, model uncertainties and external disturbances were estimated by the designed extended state observer. On this basis, a controller was developed based on the feedback control technique. Finally, a series of simulations were carried out to show that the control scheme is effective and robust.

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Hydrogen production by wind and solar hybrid power generation is an important means to solve the strong randomness and high volatility of wind and solar power generation. In this paper, the permanent magnet direct-drive wind turbine, photovoltaic power generation unit, battery pack, and electrolyzer are assembled in the AC bus, and the mathematical model of the wind-solar hydrogen storage coupled power generation system and the simulation model in PSCAD/EMTDC are established. An energy coordination control strategy is designed. After simulation, the proposed control strategy can effectively reduce the rate of curtailment of wind and solar power, and stabilize the fluctuation of wind and solar power generation. It verifies that the established model is correct and the control strategy is effective and feasible.

Open Access
Research article
Continuation Power Flow Analysis of Power System Voltage Stability with Unified Power Flow Controller
youcef islam djilani kobibi ,
mohamed abdeldjalil djehaf ,
mohamed khatir ,
mohamed ouadafraksou
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Available online: 10-29-2022

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The rising power demand has forced power systems all over the world to operate very close to their stability limits. When power systems are overloaded, faulty, or in lack of reactive power, voltage collapses would ensue. The capacity of a power system to keep the voltage of every bus constant under disturbances is called voltage stability. This dynamic phenomenon hinges on the load features. It is commonly known that flexible AC transmission systems (FACTS) can improve voltage stability. This paper puts forward a load flow model with the unified power flow controller (UPFC), and relies on the model to investigate the voltage stability of a power system through continuation power flow (CPF) method. The validity of the model was verified through a simulation, using the power system analysis toolbox (PSAT) in MATLAB/Simulink environment.

Open Access
Research article
An Efficient Reconfigurable Cryptographic Model for Dynamic and Secure Unstructured Data Sharing in Multi-Cloud Storage Server
parashiva murthy basavanapura muddumadappa ,
sumithra devi kengeri anjanappa ,
mallikarjunaswamy srikantaswamy
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Available online: 10-29-2022

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This study designs a reconfigurable multi-cloud storage server architecture for dynamic and secure data sharing has been designed, improves the security of unstructured data using cryptographic index-based data slicing (CIBDS), and reduces the malicious insider through data encryption using a third data encryption algorithm (3DEA). Focusing on multi-cloud storage server (MCSS) and data life cycle which includes three stages (i.e., data input, transition and utilization), the authors determined the efficiency of reconfigurable data file slicing, standard format, privacy and trustworthiness of the customers, in contrast to existing methods. Every part of a data file was encrypted using 3DEA, and Rivest Shamir Adleman (RSA) was employed to produce the private key to secure the unstructured data. The results show that the proposed framework effectively searches the data files in MCSS based on tags, such as input file names and private keys. The performance of the framework was measured by the security level, uploading/downloading latency time between our method and conventional methods, under different data sizes in (MB). Overall, our method reduces the malicious insider to 0.23% using 3DEA and RSA, during data encryption in the existing USDS-MC, shortens the uploading/downloading latency time (s) by 10% and 12%, compared to USDS-MC, and enhances the unstructured data security by 12% in comparison with that method. In this way, the authors managed to improve the self-protection of reconfigurable and secure unstructured data files in huge cloud infrastructure. This research optimizes the data security and privacy of encryption, decryption and cryptography technologies, and helps with the online process and its security maintenance during cloud storage.

Open Access
Research article
Hybrid Approach Control of Micro-Positioning Stage with a Piezoelectric Actuator
ounissi amor ,
azeddine kaddouri ,
rachid abdessemed
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Available online: 10-29-2022

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For a class of system with nonlinear hysteresis, this paper presents an adaptive hybrid controller based on the hybrid backstepping-sliding mode, and describes the controller analytically by the LuGre model. Both backstepping and the sliding mode techniques are based on the Lyapunov theory. Drawing on this common point, the authors developed a new controller combining the two control techniques with a recursive design. The design aims to achieve two effects: assuring the stability of the closed loop system, and improving the continuous performance of the tracking position trajectory. The performance of the proposed hybrid controller was verified by implementing the identified Piezo model. The results show that our controller can track the system output desirably with the reference trajectory.

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Creating a fair replenishment strategy is one of the most significant instruments in the inventory management for automotive spare parts. It is also crucial to controlling the enterprise's inventory level. This study considers the significance of retailers' demand forecasting at the conclusion of the sales period to build a lateral transfer inventory optimization scheme with high scientific rigor, aiming to ensure the correctness and logic of the replenishment strategy. To provide a more scientific direction for the inventory management of an automotive spare parts company, this research constructs an upgraded particle swarm optimization (PSO)-backpropagation (BP) neural network prediction model, and a lateral transfer inventory optimization method based on demand forecasting. Finally, 26 retailers of Company B in Central China's Hunan Province were taken as examples to confirm the model's efficacy. The outcomes demonstrate an improvement in the lateral transfer's applicability in Company B.

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