bluuebunny/crossref_metadata_2025_split huggingface dataset:
The utilization of mushroom growing media waste as raw material for biogas production: energy productivity ratio (EPR) study
Authors: Irvan  , Trisakti B , Nabilah Y 
Published: April 2021

Abstract
Indonesia is one of the countries with the largest crude palm oil (CPO) production. Besides CPO production the mills also produce various type of wastes in large quantity. Oil palm empty fruit bunches (OPEFB) are the largest solid waste produced during the process. One of the OPEFB utilizations that has been done by the community around the mills area is to make mushroom as growing media. However, the rest OPEFB from mushroom media which cannot be degraded becomes a new problem for the community. The technology that can be used to overcome this waste is the anaerobic composting process. This paper describes the utilizing OPEFB waste from the rest of the mushroom growth media into energy through the anaerobic composting process. The energy productivity ratio (EPR) was also calculated and reviewed during the process and utilizing by products in the output. The result revealed that the design of OPEFB waste treatment into biogas and its purification are expected to be applied to the concept of clean production (zero waste) and the productivity ratio of energy values obtained from calculations was > 1. This shows that the needs of energy output in the pilot plant are greater than the input.
Antioxidant activity of liverworts Marchantia paleacea Bertol. from North Sumatra Indonesia
Authors: Siregar E S , Pasaribu N , Sofyan M Z 
Published: April 2021

Abstract
Research on antioxidant activity of Marchantia in Indonesia is still limited. The objective of the study is to investigate the antioxidant activity of Marchantia paleacea from North Sumatera, Indonesia. The method of extraction in this study using maceration with methanol. The antioxidant activity of extracts were evaluated by 1,1diphenyl-2-picrylhydrazyl (DPPH). Vitamin C was used as positive control. The results showed that the extract of M. paleacea has antioxidant content with LC50 value of 25.25 μg/mL. The antioxidant activity of M. paleacea is classified as a strong category. The results obtained in the recent study indicate that M. paleacea is a potential source of natural antioxidant.
Damage Identification of Semi-Rigid Connection in Structures Based on Nonlinear Vibration Characteristics
Authors: Zhuo Debing , Cao Hui , Zhang Xiaobing 
Published: April 2021

Abstract
A damage-detection methodology based on nonlinear vibration characteristics was presented in this paper to identify damage of semi-rigid connections due to looseness of high strength bolts. In various damage cases caused by different loose severity of bolts in different positions, a specimen with semi-rigid connections was test and acceleration signals of free vibration were recorded by sensors placed at its both ends. The recorded signals were then dealt with by wavelet de-noising and blind source separation to get the first vibrational components. By Hilbert transform of these components, the amplitude-frequency curve of each case was obtained. The results showed that vibration of the specimen with semi-rigid connections presented typical nonlinear characteristics. With the increase of connection damage, the nonlinear degree increased accordingly. When one end had larger connection damage than the other one, it exhibited greater nonlinear extent. The results prove that it is valuable to apply the suggested nonlinear vibration characteristics based procedure to identification of semi-rigid connection damage.
Attenuation Zones of Combined Periodic Foundations with Different Combination Patterns
Authors: Liu Xinnan , Ren Yiqiang , Song Xiaoruan , Ji Yingbo 
Published: April 2021

Abstract
One-dimensional periodic foundations with single-size unit cells are difficult to possess attenuation zones with both low frequencies and wide bandwidths. Combined one-dimensional periodic foundations are proposed by combing unit cells with different sizes in tandem in this paper. Attenuation zones of combined one-dimensional periodic foundations with different combination patterns are compared. The present study is useful for the design of one-dimensional periodic foundations to isolate low frequency seismic waves.
Research on Contact Explosion Response of Reinforced Concrete Slab
Authors: Wei Demin , Hu Chenxi 
Published: April 2021

Abstract
In order to compare the contact explosion response of reinforced concrete in the air to that under the water, a FEM model based on multi-material fluid-structure coupling method is constructed to simulate the responses and failure process of two-way reinforced concrete slabs under contact explosion. The model is verified by fellow tests, then used to calculate dynamic responses and damage conditions of two-way reinforced concrete slabs subjected to underwater contact explosion and air contact explosion. It is found that the local destruction area of the slab subjected to underwater contact explosion roughly turned into a circle, while it turned into a rhombus for air contact explosion. Nonetheless, the damage of the reinforced concrete slab subjected to underwater explosion is more serious.
Analysis of Economic Thickness and the Suitable Insulation Thickness of External Wall Insulation Layer
Authors: Shen Tianqing , Shen Xingwei 
Published: April 2021

Abstract
From the view of appropriate technology, this paper compares and analyzes the calculated thickness, feasible thickness, economic thickness, and appropriate thickness of the external wall insulation material with the highest contribution rate from the economic point of view, and obtains the relationship, curve, and model between the economic thickness and the appropriate thickness of the thermal insulation material. The purpose is to provide a reference basis and model for the optimal design of building energy-saving external walls. It inspires the architectural designers to consider the energy conservation of buildings from the economy’s perspectives and environment to get the optimal and environment-friendly energy-saving design method. The purpose is to provide a robust theoretical basis for guiding energy-saving housing investment and reducing the blindness of investment.
Simulation Study on the Influence of Indoor and Outdoor Ventilation on Thermal Comfort in Zero Energy Buildings
Authors: Gao Chunxue , Xiang Jintong , Wu Songlin , Liu Qiuxin 
Published: April 2021

Abstract
Based on the rational utilization of natural wind, it is particularly critical to study the role of natural ventilation convection in zero energy buildings, so as to reduce building energy consumption and lay a good foundation for realizing the goal of zero energy consumption in buildings. The commercial software PHOENICS is used to numerically simulate the outdoor wind environment of the building complex layout and the indoor ventilation of the building itself. After a comparison analysis of simulation models, this paper first points out the main factors that affect the wind environment and indoor natural ventilation of the building complex. Reasonable suggestions were given to the architectural planning and design as well as the living habits of the residents which can save energy to the greatest extent. With these suggestions, the unnecessary energy consumption of air conditioning can be reduced on the premise of ensuring the indoor temperature and humidity environment which is very beneficial to the realization of zero energy consumption of buildings.
Research on BIM Reconstruction Method Using Semantic Segmentation Point Cloud Data Based on PointNet
Authors: Xiong Zhaoyang , Wang Ting 
Published: April 2021

Abstract
As the construction industry is shifting from the construction of new buildings to the maintenance and use of existing buildings in recent years, the demand for automated building information models (BIM) creation is increasing. This paper uses the deep learning network PointNet to perform semantic segmentation on the public S3DIS point cloud data set, which means to assign the same type of point cloud building components in the data set to the same label, and the bounding box algorithm is been used to obtain the outer contour parameters of the segmented point cloud building components. Finally, the Dynamo, which is one of the Revit plug-in, is used to perform parametric modeling according to the obtained parameters, and generates the BIM corresponding to the point cloud data set. The experimental results show that the method proposed in this paper can complete the parametric creation of BIM with high completeness based on the efficient segmentation of point clouds.
Research on the Durability of Composite Pile Made of Ultra-High-Performance and Common Concrete: Finite Element Analysis
Authors: Li Wei , Li Yiping , Shang Jianguo , Chen Yuhong , Zu Jinlong 
Published: April 2021

Abstract
The paper is to study the durability of transmission tower foundation using a combination of ultra-high performance concrete (UHPC) and common concrete (NC) in salinealkali region. The composite pile is made of outer UHPC sleeve and core ordinary concrete. Due to the excellent durability of UHPC, the outer UHPC sleeve can prevent chloride ion and sulfate ion corrosion as well as save cost. Computer research technology was used to construct a corresponding natural environment for artificial simulation, hence accelerate the experimental test of the natural environment. It can more directly and effectively reflect the durability problems of the actual projects. This paper follows the application of classical similarity theorem of UHPC-NC foundation under saline-alkali erosive environment in Gansu, concrete test beams with the same material composition and structural characteristics were poured, an accelerated artificial simulation was designed. Results on the finite element simulation revealed that the outer wrapped ring of UHPC can effectively block the transmission of chloride ions from the external environment to the center of the cross-section. Under the same environment and operation time, the penetration depth of chloride ion in UHPC-NC combined cross-section is much smaller than that in pure normal concrete cross-sections. Therefore, it can be seen that the UHPC-NC combined cross-section can prevent the penetration of chloride ions in a saline-alkali environment, thereby effectively improving the durability of the transmission structure foundation, and hence ensuring the safety and applicability of electricity transmission structure during operation phase.
Experimental Study on the Influence of Vibration Mixing Technology on Engineering Characteristics of Steel Fiber Reinforced Concrete
Authors: Zhang Genhe , Hu Min , Jia Wenyuan , Liu Zhonghua , Li Taotao , Yao Yunshi , Liu Huanjian 
Published: April 2021

Abstract
In order to improve the problems of uneven dispersion, easy agglomeration and insufficient mechanical properties of steel fiber reinforced concrete, vibration mixing and conventional mixing were used to prepare two kinds of test samples. The effects of vibration mixing and conventional mixing on the compressive strength, splitting tensile strength and flexural strength of steel fiber reinforced concrete were compared and analyzed. The results show that, compared with the conventional mixing, vibration mixing compression test can better maintain the integrity of the specimen, only a small number of cracks and small gap, no integral extension cracks appear. Compared with conventional mixing, the average compressive strength of steel fiber concrete for 3d, 7d and 28d under vibration mixing increased by 12.9%, and the splitting strength increased by 12.3%, and the flexural strength increased by 16.8%, and the mechanical properties were strengthened. It provides a reference for the effective application of vibration mixing steel fiber concrete in engineering structure.
Study on Spatial Configuration of Operating Pipe String in Wellbore
Authors: Wang Wenchang , Feng Dajun , Rui Zixiang , Di Qinfeng , Chen Feng 
Published: April 2021

Abstract
The buckling of operation pipe string may occur under complex load in deep well. The serious buckling of the string will lead to partial wear, break or even self-locking, which is detrimental to the downhole operation. At present, most of the studies have focused on the string buckling stability and characteristics of single buckling pattern, and the spatial configuration of entire operation pipe string was seldom studied. In fact, the entire operation pipe string of deep well under complex loads may present a complex configuration consisted of non-buckling, sinusoidal buckling and helical buckling. In this study, the smooth connection condition of different deformation states of pipe string is proposed, and combining the buckling stability analysis and boundary influence characteristics, the spatial configuration of the entire operation pipe string in the borehole could be solved. A field example was given, and the variation of the spatial configuration of the entire operating string with injection pressure is analyzed in detail. The results showed that the calculation method proposed is very useful and important to determine the operation parameters in-situ, to know the working state of the downhole operation string. This works is helpful to avoid the complex situation or accidents in completion practices.
Optimization for Connected Steel Plates of Single-Layer Shaft Wall under Blasting Excavation by Numerical Simulation Method
Authors: Xie Lidong , Gao Xingyuan , Yang Yu , Zhi Youhai , Dong Zhaoxing 
Published: April 2021

Abstract
In order to increase the cross-section utilization rate of the deep shaft, a new type single-layer wall with connected steel plates has been invented. The numerical simulation method is used to analyze the coupling interaction between the steel plate and the concrete. The results show that: there are four vibration strengthening regions in each formwork wall. The order from strength to weakness for the regions is as follows: the concrete outside of vertical steel plate > the concrete at the interface between shaft wall and rock wall > the concrete on the upper side of each formwork > the concrete on the lower side of each formwork. There are two potential leakage channels in the vicinity of the connected steel plate, and the channel under the inclined steel plate is a controlled channel. The thickness of steel plate has an important influence on the damage degree and range of concrete. The concrete damage is affected by vertical steel plate, inclined steel plate and thickness combination of themselves. When the project takes the inclined steel plate 10 mm and the vertical steel plate 6 mm, the phenomenon of crack and leakage of the concrete wall is greatly reduced, and the quality of the project is good.
Application of WBS in Pricing Management of Prefabricated Concrete Construction Project
Authors: Su Jinli , Zheng Xiaolu 
Published: April 2021

Abstract
The standard of measurement and valuation is the main basis for making the bill of quantities and compiling the bidding control price and bidding quotation. In recent years, prefabricated concrete building, as a typical structural form of prefabricated building, has developed rapidly. However, in the actual operation of measuring and pricing of prefabricated concrete construction projects, the existing list system has many shortcomings. Based on this, it is necessary to optimize the measurement specifications of prefabricated concrete buildings in China. At first, this paper USES the principle of the work breakdown structure (WBS) specifications for the measurement of the current prefabricated concrete building structure is analyzed, secondly in jinan city project as an example, to find out its branch, the branch of engineering and engineering subdivisional work on decomposition structure of the preliminary optimization, using WBS to metrological specification for the perfection of prefabricated concrete construction measurement valuation in China to provide the basis.
Research on the Construction Technology for the Reconstruction of Existing Retaining Piles under the Condition of the New and Old Foundation Pits in Close Proximity
Authors: Xie Junkai , Gao Bo , Chen Guanghua 
Published: April 2021

Abstract
In view of the development of the city and the development and utilization of underground space, the new building foundation pit is close to the existing foundation pit. In view of this problem, a common reconstruction technology of existing retaining piles under the condition that the new and old foundation pits are adjacent to each other is proposed. The main construction process includes: primary selection of common pile section, design change, bored pile inspection, construction of steel pipe pile with pilot hole, depth judgment of new and old foundation pit, construction of locking anchor rod, foundation pit construction, monitoring and acceptance, etc. The reconstruction and reuse technology of the existing foundation pit supporting pile has been applied in a foundation pit in Zhuhai, which proves that it is safe and reliable, saves the construction period, reduces the construction difficulty, and improves the construction efficiency, which can provide reference for similar projects.
Study on Mechanical Behavior of Fabricated PC Floor Structure in Construction Engineering
Authors: Lu Qunfu , Zhang Zhengen , Zhou Bingyang 
Published: April 2021

Abstract
In order to obtain the best fabricated floor structure for construction projects, based on the non-linear finite element software ABAQUS, the PC floor and cast-in-place floor slabs of the C30 floor slab scheme of the Jiangyin Jinyi Project were fully simulated. Through the comparison of the two simulation results, it is found that the stress concentration at the center of the cast-in-place floor structure under the full static load is significantly greater than that of the PC floor structure; unlike the uniform force of the PC board, the most vulnerable position of the cast-in-place floor structure is The longer side is not the uniform force of the overall floor structure; after checking the ultimate bearing capacity, strength and deflection of the PC floor structure, it is found that the ultimate bearing capacity of the PC floor structure is 9.187 kN/m and the deflection is 0.049 mm, which are far less than The theoretical value of the design of the floor structure shows that it is feasible to select the PC floor structure in the assembly type of construction engineering, and it is recommended to popularize and apply it in engineering practice.
Strength and Deformation Characteristics of Fiber Reinforced Longdong Loess and Experimental Study of Modified Duncan -Chang Model
Authors: Chu Feng , Luo Jingbo , Yang Wenpeng , Shao Shengjun , Yu Yongtang , Xu Chuanzhao 
Published: April 2021

Abstract
Fiber yarn reinforced loess is prepared through mixing plain loess with a certain proportion of polyester fiber yarn, which is formed by loosening, carding and cutting waste synthetic textile polyester fabric and has rough surface properties and good acid-alkali corrosion resistance. The strength and deformation characteristics of Longdong Loess reinforced by fiber yarn were studied. The test results show that the uniaxial compressive strength of fiber yarn reinforced loess increases with the increase of fiber yarn proportion and fiber yarn length, and decreases with the increase of fiber yarn fineness. Combined with the uniaxial compressive strength data of fiber yarn reinforced loess under the optimal water content and liquid limit water content, an index which can comprehensively reflect the reinforcement performance of fiber yarn reinforced loess is proposed-- Fiber reinforced index. The shear stress-strain relationship of triaxial consolidation drainage of fiber-reinforced loess with different proportion of fiber yarn is strain hardening type. The hypothesis of hyperbolic form is in accordance with Duncan Chang model. By discussing the relationship between the parameters of fiber yarn reinforced loess and plain loess model, the empirical expression of model parameters considering the influence of fiber yarn reinforced loess is obtained. A modified Duncan-Chang E-B model reflecting the influence of different fiber yarn blending ratio was constructed. The rationality of the model is verified by comparing the test curve with the model prediction curve.
Study on Preparation of Saturated Unstructured Loess and Its Strength and Deformation Characteristics
Authors: Chu Feng , Yang Wenpeng , Shao Shengjun 
Published: April 2021

Abstract
In the study of geotechnical damage mechanics, the weighted average of the mechanical deformation states of structurally undamaged and structurally completely damaged soils is used to describe the actual mechanical deformation properties of soils. In the past, when the saturated remolded loess was used to simulate the mechanical deformation of loess, the loess still had some initial structural strength. A method for the preparation of saturated unstructured loess is presented. The strength deformation characteristics of saturated remolded loess were compared by lateral compression test and triaxial shear test. The method of preparing saturated unstructured loess is proved to be reasonable.
Analysis of Low-Temperature Damage of Reinforced Concrete Beams Using Acoustic Emission Parameters
Authors: Li Jianfeng , Ye Zhoujing , Zhao Kang , Yang Zhihao , Gao Zhifei , Wang Linbing 
Published: April 2021

AbstractReinforced concrete (RC) beams will be affected by various external environmental in the service process, of which low-temperature is a representative factor. This paper presents a study on using the low-temperature damage test on damage and fracture of RC beams, and an acoustic emission (AE) system is used to monitor the whole process of testing. In the low-temperature damage test, AE hits are used to characterize the damage of each cooling step, and the low-temperature damage of the beam is divided into three processes: initial damage, extended damage and attenuated damage. A damage parameter (DTEM) based on the accumulated energy of AE is used to analyze the whole process of low-temperature damage of the beam, and the percentage of low-temperature damage in each cooling step is obtained. The environment chamber is used to simulate the extreme low-temperature environment, and the damage of RC beam after the sudden temperature drop (process I) and the end of cooling (process II) is obtained. These two processes have important reference value for the damage degree analysis and damage warning of RC beams in the actual extreme low-temperature environment.
Numerical Simulation Analysis of Surrounding Rock Deformation of Expansive Rock Roadway under Humidity Field
Authors: Diao Shichen , Hong Peng , Fu Yu , Mao Xiaobo 
Published: April 2021

Abstract
Based on the measured distribution law of humidity field, according to the humidity stress field theory, the coupling of the humidity field and the ground stress field is realized, and the humidity field is systematically analyzed. Under the conditions, the influence of the expansion of surrounding rock, lining, buried depth, height-span ratio and horizontal pressure coefficient on the deformation of the surrounding rock of the roadway, the general law of the surrounding rock deformation of the swelling rock roadway is obtained. The results show that the five factors have a certain impact on the approaching amount of the two sides of the surrounding rock and the approaching amount of the roof and floor of the swelling rock roadway, but the degree of influence is different. The order of factors affecting the approach of two sides is lining > expansibility > buried depth > horizontal pressure coefficient > height-span ratio; The order of factors affecting the approach of roof and floor is lining > expansibility > height-span ratio > horizontal pressure coefficient > buried depth. The research results provide valuable suggestions and references for the selection of reasonable support schemes and related design and construction of swelling rock roadways.