bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of BP neural network models in predicting the desulfurization rate of petroleum coke calcination flue gas
Authors: Lv Y W , Zhu Y , Jiang Y X , Xue L , Zuo L
Published: December 2020

Sulfur-containing prebaked anodes, mainly made from petroleum coke, can give rise to SO2 emission in the production of electrolytic aluminum. In order to study the correlation between the emission volume and desulfurization rate of the flue gas discharged from the calcination of petroleum coke, a traditional double hidden layer BP neural network model was established on the basis of BP neural network by taking the emission data of the petroleum coke calcination flue gas desulfurization system as input parameters. This model was used to predict the desulfurization rate of the petroleum coke calcination flue gas desulfurization system, with an aim to control the SO2 removal rate of flue gas through controlling the flue gas parameters of the desulfurization system, so as to reduce SO2 emission from the flue gas of the electrolytic aluminum industry. The study will be of practical significance for the SO2 removal of the petroleum coke calcination flue gas.
Classification and applicability analysis of ecological revetment in different types of river
Authors: Liu L L , Wang Y C
Published: December 2020

In this paper, we classified and summarized 25 kinds of ecological revetment commonly used at home and abroad in recent years according to river hydraulic characteristics and special functions. This paper focuses on the characteristics, materials and technical methods of these ecological revetments, and analyzes the advantages and disadvantages of ecological revetments from the aspects of ecology, landscape, construction, structure, economy and application. Combined with the ecological effects of these ecological revetment, the application scope and promotion significance of these ecological revetment are given, which plays a positive role in the promotion and application of ecological revetment.
The simulation of water quality control of Fengping section in Mangshi River
Authors: Li D T , Liu G , Wu S
Published: December 2020

The assessment of water quality is mainly based on Environmental Quality Standards for Surface Water (GB3838-2002), which divided surface water into five classes (Class I to Class V) according to its purpose for use and protection target. In April 2015, the State Council issued an Action Plan for the Prevention and Control of Water Pollution, which is a law formulated to effectively increase the prevention and control of water pollution and ensure national water safety. In 2016, the Yunnan Provincial People’s Government and the Dehong Prefecture People’s Government successively proposed work plans for the prevention and control of water pollution, requiring the Fengping Section (State Control) in Mangshi River to reach Class III of surface water by 2020. But the current water quality fluctuates between Class III and V. Based on the current status of water quality and pollution sources, the paper uses HD (hydrodynamic model) and AD (hydrodynamics advection diffusion model) in MIKE 21 FM model to establish the two-dimensional water quality model to simulate the distribution characteristic of different water quality parameters, which are Biochemical Oxygen Demand (BOD5), Total Phosphorus (TP), Ammonium Nitrogen (NH3-N). The conclusion is that reduction targets of BOD5, TP and NH3-N are namely 40%, 30% and 10% to ensure water quality, which guides the formulation of pollutant emission reduction plans more scientifically.
Analysis of the vitality measurement and correlation factors of urban waterfront space
Authors: Wang F , Zhao M X , Meng Q L
Published: December 2020

The long-term development of the city benefits from the creation of space vitality, and the vitality of waterfront space is an important factor that constitutes the city’s characteristic landscape. This paper uses mobile phone signaling data to measure the development trend of waterfront space from the perspective of crowd vitality through nuclear density analysis, paired sample test, and OD matrix analysis. In addition, the influencing factors of waterfront space development differences are measured by Geographic Weighted Analysis (GWR), so as to provide scientific theoretical basis for the layout of waterfront space construction in new cities. The study found that the construction of the waterfront space of the Qijiang River shows the trend of waterback development. The vitality of the waterfront space at different moments shows that the waterback trend of the waterfront space is more obvious during the day. And the main influence mechanism of the vitality of the waterfront space shows that the vitality of the waterfront space has a great correlation with the public service and commercial land, green space, residential land, the diversity of public facilities, the number of residents and the density of the road. Therefore, it is necessary to put forward the development strategy of waterfront space to optimize the regional development.
Water quality assessment of the river network in Wenzhou city using PCA-BP neural network model
Authors: Zhou F , Tian C C , Xu J L , Wei J
Published: December 2020

The water quality assessment is often challenged by how to determine the index weight and simplify the evaluation model. This paper proposed an integrated model called PCA-BP neural network model to solve the problem, which combines the dimensionality reduction capability of the improved principal component analysis (PCA) method with the self-learning ability of back propagation (BP) artificial neural networks. And its application for the plain river network in the main districts of Wenzhou city indicated that the evaluation result of PCA-BP was consistent with the single-factor method and PCA method in overall trend. It was demonstrated that PCA-BP model could evaluate the water quality of the study area more reasonably and accurately, as it avoided the disadvantage of a certain factor completely covering the information of the other ones in the single-factor method and the risk of over-optimism in PCA method as well.
Effect of hydrological regime on the sediment bacterial diversity and community structure in Sultanpur Lake, Gurugram, Haryana
Authors: Bhat Sandhya , Pamposh
Published: December 2020

The present study focuses on the changes in sediment bacterial community structure and diversity of Sultanpur Lake due to changes in its hydrological regime. The assessment of the bacterial community structure was done by using the Next Generation Sequencing of 16S rRNA amplicon, a bacterial phylogenetic marker. Sultanpur Lake is located in Sultanpur National Park Gurugram, in the state of Haryana, India. This place harbors great plant and animal biodiversity and serves as an important feeding, roosting and breeding ground for both resident and migratory avian fauna. Increasing pollution level and scarcity of water during summer months impose a great threat to the lake. Sediment bacteria are considered as reliable recorders of nutrient cycling and active mediums of biogeochemical processes and thus were assessed in this study. Wet and dry sediment samples were taken and analyzed for their bacterial community structure and diversity. The amplicon sequencing generated 881,118 reads which corresponded to 93 known species in case of dry sediments and 8,71,102 reads corresponding to 44 species in case of wet sediments. In dry sediments the top ten phyla were Firmicutes (26%), Bacteroidetes (14%), Proteobacteria (15%), Cyanobacteria (12%), Parcubacteria (7%), Euryarcheota (6%), Actinobacteria (5%), Armatimonadetes (5%), Chloroflexi (2%) and Planctomycetes (2%). In case of wet sediments, the top ten phyla were Firmicutes (35%), Bacteroidetes (22%), Proteobacteria (22%), Actinobacteria (7%), Chloroflexi (5%) Parcubacteria (3%), Verrucomimicrobia (3%) and, Deinococcus-Thermus (3%). There was change in the community structure at species level too with Clostridium species as the most dominant species in case of wet sediments and Lactobacillus species as the predominant one in dry sediments. This study provides an insight into the changes in the bacterial communities due to changes in hydrology and how this change will affect the health of this wetland as irregular water supply is a major stressor of this wetland.
Evolution characteristics research on summer-autumn consistent drought of Poyang Lake based on the copula in the changing environment
Authors: Xu B , Yuan Z , Sun K K , Lin Y R
Published: December 2020

The precipitation series is the main data to calculate the parameters and the frequency of drought, aim to the less considering with the inconsistency of precipitation series in study of drought research under the changing environment, and the less reasearch on the drought evolution characteristics within the basin before and after the hydrological alteration, the hydrological alteration diagnosis system was used to diagnose the summer and fall precipitation series of Yichun, Nanchang etc. and 9 meteorological station in total within the basin of Poyang lake. Based on the hydrological alteration results and considering the Copula function, the percentage of precipitation anomaly (Pa) was taken as the drought index to calculate the percentage of summer-fall consistent drought of meteorological stations. The results show that, the alteration of precipitation series in summer was obvious at Poyang lake, comparing with the period before the alteraion, the percentage of summer-fall consistent drought of Poyang Lake is decreasing, that means the recurrence period of summer-fall consistent drought becomes longer, the main reason that induce the much more serious drought in the Poyang Lake is the factor of water expenditure.
Multi-objective ecological operation of cascade reservoirs based on MGCL-PSO algorithm
Authors: Wang T , Mo L , Shen Q , Zou Y B , Yi M
Published: December 2020

The reasonable utilization of river water resources requires the joint operation of cascade reservoirs. Aiming at power generation and ecological environment protection, taking the Qingjiang cascade reservoir group as the research object, a multi-objective optimization model for maximum power generation considering ecological base flow and minimum ecological flow changed is established. The results of the multi group cooperation operation particle swarm optimization (MGCL-PSO) model based on population cooperation show that the multi-objective of power generation and ecology can achieve a better balance by slightly reducing the power generation. Several schemes with good convergence are obtained from the calculation results, which provide a reference for the operation of cascade reservoirs.
Study on the relationship between inorganic nitrogen or phosphorus and dissolved oxygen in seawater
Authors: Lin Z G , Du J L , Feng L Q , Li G , Xu R , Yang Y
Published: December 2020

We analyze the linear correlation between dissolved inorganic nitrogen (DIN), phosphate (PO4-P) and dissolved oxygen (DO) based on on-site monitoring data at Zhoushan in May 2016, and construct the DIN, PO4-P and DO related model using neural networks in this paper. Based on the model, we predict the concentration of DIN and PO4-P in seawater by DO data. From the data analysis, the root-mean-square error of prediction (RMSEP) is less than 0.2, and the predicted values of DIN (including NH3-N, NO2-N, and NO3-N) and PO4-P are basically consistent with the changes in measured values. The correlation coefficient between NO2-N and DO is the largest at 0.6247, and the RMSEP is the smallest at 0.1119.
Draw on artificial neural networks to assess and predict water quality
Authors: Fernandes A , Chaves H , Lima R , Neves J , Vicente H
Published: December 2020

Water is one of the important vehicles for diseases of an infectious nature, which makes it essential to assess its quality. However, the assessment of water quality in reservoirs is a complex problem due to geographic limitations, sample collection and respective transport, the number of parameters to be studied and the financial resources spent to obtain analytical results. In addition, the period between sampling and analysis results must be added. This work describes the development of an Artificial Neural Network (ANN) to predict the biochemical and chemical oxygen demand based on the water pH value, the dissolved oxygen, the conductivity and its temperature. The models were trained and tested using experimental data (N=605) obtained from superficial water samples used to irrigate and produce water for public use, collected between September 2005 and December 2017. To evaluate the performance of the ANN models, the determination coefficient, the mean absolute error, the mean square error and the bias were calculated. It was determined that an ANN with topology 4-6-5-2 could be used successfully to predict the variables’ output. Indeed, good agreement was observed between the observed and predicted values, with the values of the coefficient of determination ranging from 0.813 to 0.979.
Prediction of octanol-water partition coefficients for alkyl-PAHs based on the solvation free energy
Authors: Li W R , Song G B , Ding G H , Gao H
Published: December 2020

Octanol-water partition coefficients (KOW
) are of great importance in assessing the environmental fate and risk of hydrophobic organic pollutants including alkyl-polycyclic aromatic hydrocarbons (alkyl-PAHs). Due to the time-consuming and laborious of experimental determination of KOW
, it is desirable to develop a rapid and accurate prediction model for the KOW
of alkyl-PAHs. In this study, a prediction model for log KOW
of alkyl-PAHs was developed according to the thermodynamic relationship between KOW
and the solvation free energy from n-octanol phase to aqueous phase (ΔGOW
). ΔGOW
values of alkyl-PAHs were calculated by the SMD model. The effect of dimer formation on the partition behaviour and partition coefficient was explored. After taking the effect of dimer formation into account, the goodness-of-fit, predictive ability, and robustness of the prediction model was significantly improved. The developed model in this study had the superiorities of universal application domain, low dependence on the experimental values and clear model mechanism.
Runoff simulation of Tangnaihai hydrological station in source area of Yellow River based on SWAT model
Authors: Li K , Wang Y Q , Xu J J , Hong X F , Feng Y
Published: December 2020

Studying the applicability of the SWAT model in the source area of the Yellow River is helpful for the comprehensive management of water resources and hydrological cycles in the source area of the Yellow River. The SWAT monthly runoff simulation model was constructed using DEM data, land use data, soil data and meteorological station data in the source area of the Yellow River, and the parameters were calibrated using the SUIF-2 algorithm in SWAT-CUP2012, with determation coefficients R2 and Nash-Sutcliffe efficiency coefficients (NSE). The results show that the fit between the monthly runoff simulation process and the measured runoff process in the source area of the Yellow River is close. The R2 and NSE were 0.77, 0.76, 0.90, and 0.89 in the model calibration period 2000∼2009 and verification period 2010∼2013, respectively. This shows that the SWAT model simulates the monthly runoff process of the source area of the Yellow River satisfactoriy, that is, the SWAT model e has good applicability in the Yellow River source area.
Comparison of the modified Monod and Droop function combined with Logistic function for describing algae growth
Authors: Kong W W , Huang S L , Shi F F , Yang Z J , Feng Y B , Khatoon Z
Published: December 2020

Microcystis aeruginosa (M. aeruginosa) are algae found in common freshwater blooms in China, and Dunaliella tertiolecta (D. tertiolecta) are economically important marine algae. Understanding of the microbial growth kinetics plays a significant role in the management of M. aeruginosa’s blooms and biodiesel production by D. tertiolecta. This study has shown that the combination of mechanistic models (Logistic and Monod) proved to be efficient in describing relationship between M. aeruginosa growth rates and specific concentrations of total dissolved phosphorus (TDP), orthophosphate (PO4
3--P), total dissolved nitrogen (TDN) and ammonia (NH4
+-N) reasonably with R2=0.28-0.93. Meanwhile, results also show that both PO43--P and NH4
+-N are important forms of TDP and TDN in influencing M. aeruginosa growth. It was also noted that the combination of modified Monod and Logistic functions is suitable for describing specific growth rates of D. tertiolecta versus extracellular nitrate concentrations (R2=0.24-0.72). In terms of the combination of Droop and Logistic functions, it was analysed to better explain the relationships between M. aeruginosa specific growth rates and cellular P and N concentrations (R2=0.41-0.86) as compared to the application of Droop function alone. It is also observed that the relationship between D. tertiolecta specific growth rates and intracellular nitrate concentrations also can be well described by the combination of Logistic and Droop functions. In addition, M. aeruginosa growth was affected by less intracellular P concentrations than intracellular N concentrations. In sum, the combination of modified Monod and Logistic functions and the combination of Droop and Logistic functions all can predict algae growth reasonably well, while the combination of Droop and Logistic functions is slightly better. Meanwhile, it is through these two combinations that two sets of better parameters in modified Monod and Droop functions can be respectively obtained to characterize algal population kinetics with changing nutrient concentrations.
High-resolution hydrometeorological forecast in Southwest China based on a multi-layer nested WRF model
Authors: Chen Z N , Li J , Zhu Y , Hu L C , Wen X , Lei X H
Published: December 2020

In this study, a high-resolution (5km:1km) regional hydrometeorological simulation (Weather Research and Forecasting, WRF) in Southwest China was evaluated by comparisons with the multiple General Circulation Model (multi-GCM) ensemble mean from Coupled Model Intercomparison Project phase 5 (CMIP5) and in-situ observation data, to prove its advantage to precisely delineate the regional complex topographical and climatic conditions. The temperature and precipitation were selected to evaluate the model performance skills. Simulations of the spatiotemporal rainfall and near-surface air temperature distribution across the entire research area and at four specific sites (Ganzi, Daofu, Jiulong Huili) were analyzed based on observational data from 2007–2010. Overall, both the WRF and multi-GCM demonstrated satisfactory capabilities in representing seasonal variation, but systematic biases remained. The regional average near-surface air temperature of WRF outputs had cold biases of −4.91, −1.96, −3.92 and −8.17°C in spring, summer, autumn and winter, respectively, and wet biases of 40.5 – 428.5 mm in cumulative precipitation over the four seasons. Overall, the multi-GCM means had consistent bias, but were closer to regional averages derived from in-situ data. At the four validation stations, the WRF outputs consistently performed better for temperature and precipitation according to the correlation coefficient, root-mean-square error, and index of agreement. The simulation capabilities identified herein can serve as a foundation for addressing WRF model biases and improving projection accuracy in the future.
Analysis of the influence of stratum on karst development features: Taking Longtan river basin in Youyang County as an example
Authors: Chu X F , Yu S , Wei K X
Published: December 2020

As the carrier of karst water, the stratum is capable of impacting the water yield property and karst development features, so this paper aims to find out how the stratum characteristics affect the karst water. The study site was Longtan river basin, a typical area of karst topography, located in Youyang County, Chongqing, China. Throng the statistics and analysis of the characteristics of karst water and strata, it was obvious that the thickness of strata has a significant impact on the karst water. In epi-karst, it was demonstrated that as the rock layer thickened, the flow of karst water decreased, but the number of karst springs tended to increase. The influence law was similar in deep layers, that is the relation between the stratum thickness and the average flow could be fitted by a power function, and the stratum thickness and the length of underground river, an exponential one. In addition, the flow-rate of water yielded was likely to drop fairly rapidly while the strata get deeper. Therefore, this paper successfully put forward a method, which can estimate the water resources quantity of karst water as long as the stratum thickness was available and provide a reference for the subsequent evaluation of water-abundance.
Research on the Evaluation of Tourist Satisfaction in Wuhan City Tourism Destinations Based on the Quadrant Graph Model
Authors: Li Q , Zhang Y
Published: December 2020

Based on the research review of urban tourism and tourist satisfaction, this paper builds a tourist satisfaction evaluation model for urban tourism destinations to obtain tourist satisfaction and importance values of different evaluation indicators, and uses the quadrant graph model to evaluate the urban tourism status of Wuhan Conducted empirical research, analyzed various factors influencing tourist satisfaction and included them in the advantage zone, maintenance zone, opportunity zone and repair zone respectively, and put forward corresponding suggestions for improvement.
Study on the sensitive ecological flow of mountainous river under the action of the weir group
Authors: You A J , Hua L , Xu K P
Published: December 2020

Mountainous rivers are the key area of weir-building for water and hydroenergy storage with abundant energy resources. In view of the intensive construction of river weirs in the mountainous areas of Zhejiang Province, with the aim of meeting fish migration demand and maintaining the longitudinal continuous flow of rivers, this paper put forward the idea and method of determining sensitive ecological flow. Taking the typical section of Majinxi, a tributary of the Qiantang River as an example, the sensitive ecological flow based on the suitable flow rate of fish and the submerged flow of the weirs were calculated by hydrodynamic method. On the basis of the analysis of the hydrologic characteristics of the studied river reach, the criteria for determining effective flood pulses was put forward, and the assessment of ecological flow satisfaction was carried out. The research showed that in order to eliminate the barrier effect brought by the weir group, the short-term flood peak flow was large and low satisfied. It was proposed that fish paths or ladders should be added to the dam, or the form and density of the dam could be optimized to reduce the demand for sensitive flow.
Land use optimization by integrating GLP and CLUE-S model to control land degradation risk in mountainous area of Southwest China
Authors: Zhao X Q , Pu J W , Yang H H , Xia J S , Tan S C
Published: December 2020

Large-scale artificial plantations in mountainous areas of Southwest China have changed land use status and aggravated land degradation risk (LDR). This study taking Menglian County as an example, optimizes land use in 2025 to reduce the regional LDR, by integrating Grey Linear Programming (GLP) and CLUE-S model. Results showed that: The high-risk and medium-risk levels are main LDR types in Menglian County, accounting for 56.36% of total area. The regions with high LDR consistent with the distribution of concentrated garden land and cultivated land. The regions with low LDR consistent with the forestland. While the distribution of medium-risk regions relates to small plots garden land and cultivated land. In the optimization results, the LDR reduced 461.80, 168.95 and 34.23 in three schemes respectively, comparing to 2015. Thereinto, the strict-demand scheme has good applicability and guidance for study area relatively, in which the LDR is reduced while ensuring sustainable development. After spatial allocation, garden land, cultivated land, forestland and construction land tend to be centralized. It is effective for solving the optimal problem of mountainous land resource by integrating GLP and CLUE-S. The methods and results can provide a scientific reference for controlling LDR in mountainous area in Southwest China.
New Railway Routes, Cross Section and Water Evacuation System Problems at Tunnels in Romania
Authors: Flaviu Nica Ioan
Published: December 2020

Adoption of the maximum circulation speed of passenger trains of 160 km/h and 120 km/h for freight trains conducted to rectification of 300 Railway Magistral. In the railway rehabilitation project between Brasov and Simeria, component part of IVth Pan European Railway Corridor along Romania were provided a series of art works like tunnels and bridges. The paper presents the new constructive routes adopted in the railway rehabilitation project for three zones, corresponding to the new three tunnels: Sighisoara, Danes and Turdas and the new rail curves adopted in order to ensure the designed speed. In the second part of the paper it is made a research regarding the technical solution of tunnels cross section and the implication of the works connected. A brief comparison between the Sighisoara, Danes and Turdas tunnels cross section and the problems encountered during construction is made. In the third part of the paper are presented the deficiencies of the water evacuation canal, central canal, drainage pipes and deficiencies in conception of water drainage system of tunnels.
Developing Railway Link in Central Region of Romania
Authors: Flaviu Nica Ioan
Published: December 2020

An intersection of European Railway Corridors is present in our country by geographical meanings, conducting to a need of developing infrastructure and connecting it to the European Corridors. The railway link between the Romanian Regions is developing and has just a few sections that need to be made in order to have the entire IVth Pan European Railway Corridor from Romania rehabilitated. The Central Developing Region from Romania contains the railway section between Brasov and Sighisoara cities that is rehabilitated for the maxim design speed for passenger trains of 160 km/h and 120km/h for freight trains. The maximum design speed imposes new curves with bigger radius resulting in new routes along the section. The actual and proposed route of double track railway section between Brasov and Sighisoara is analysed and the rehabilitation works along with it. The tunnels cross section and possible difficulties in realising and execution of them are presented and analysed. Conclusions regarding the proposed art works and future problems that can be solved in this stage – preparation stage that can assure better and safe construction and exploitation of the railway are made in final.
Requalification of Housing Suburbs: Urban Project for Covilhã
Authors: Virtudes Ana , Nadai Yasmin De , Silveira Caroline , Goulart Luan , Garbini Luana
Published: December 2020

This article has a graphic and illustrative sketch of the urban requalification project for the suburban neighbourhood of Covelo, in the surroundings of Covilhã, in the interior of Portugal near to the border with Spain. It was carried out for a subject of Urban Planning of the University of Beira Interior during the mobility program with Brazilian universities. It is a low-density residential suburb of single-houses typology. The methodology applied in a first phase includes an analytical research of the area features, supported by field visits, sketch maps and municipal documents that regulate the processes of edification, urbanization and urban requalification. The second phase included the preparation of visual maps that allowed the construction of a set of conditions, weaknesses and potentialities of the area, considering its characteristics and morphological elements. In the third phase, an urban diagnosis was elaborated showing the failures of integration of this suburban neighbourhood at the urban network of Covilhã, with a massive presence of urban voids, low quality and scarcity of public spaces, undersized streets structure and lack of commercial attractiveness. In the fourth phase, the urban design solution aimed to create democratic spaces for meeting and leisure, based on concepts such as permeability, accessibility, readability, diversity, flexibility, identity and ownership of the local community, residents and visitors. The requalification project aims to clarify the public and private realms of the spaces and the creation of an environment where everyone can experience the individual and the collective within the same neighbourhood. The propose is a long-term development and should be considered in phases as the community grow. It aims to allow the neighbourhood expansion, restructuring the street network and, after that, the following steps like implantation of a small business centre. It is believed that the result is an attractive proposal for the local and that, through the urban design project, citizens will be invited to take ownership of the new public area while creating a more healthy community, with a sense of collective responsibility for its maintenance.
Systems Approach to Analysis of Destruction of Cement Composites
Authors: Selyaev Vladimir , Selyaev Pavel , Garkina Irina , Danilov Alexander
Published: December 2020

A new approach to the creation of composite materials using system analysis methods is proposed. A composite is considered as a set of elements connected by relations generating an integrative quality. When studying the properties of materials, synergetic, informational and homeostatic approaches are implemented. It is noted that when the integrative parameters of the system approach the maximum permissible, a systemic crisis occurs: the system enters the bifurcation zone. The system attributes and methods for selecting elements and subsystems are determined taking into account the paradoxes of integrity and hierarchy; their implementation is indicated in the development of radiation-protective composite materials. Issues of paradigm shift in the development of composite materials are touched upon. The new paradigm does not include the old one. It is stressed that in a paradigm shift there is no continuity of theories; Involves the formation of another system of views based on fundamentally new basic models and the change of the principle of management of initial structure formation. On identification, the principle of simulating a complex system is used (it was represented by a finite set of models that reflect a certain facet of its essence) and purposefulness (matching a complex system with many private criteria and specially developed global criteria that describe its existence as a whole). An example of the synthesis of composites based on the identification of kinetic processes of formation of their physical and mechanical characteristics is indicated. Some aspects of evaluating the durability of materials are considered; the destruction of the system is interpreted as a catastrophe associated with a violation of homeostasis. It is assumed that structural elements are formed from elementary particles, which, under the influence of external factors, are combined into molecules, clusters, globules and fibrils; associative clusters and more complex ordered packing of structural elements appear. The approaches of Benoit Mandelbrot are used, a quantum-mechanical description of the process of destruction of a solid body: a solid body is represented as a set of elementary oscillators; energy is released and absorbed by elementary portions - quanta; destruction of one structural element does not lead to destruction of the entire system; destruction is considered as a process proceeding at scale levels. An illustration is given of a systematic approach to modeling a cement composite as a complex scale-invariant system with the indication of particular models.
3D Nonlinear Analysis of Precast Prestressed Hollow Core Slab
Authors: Hollý Ivan , Abrahoim Iyad , Fillo Ľudovít
Published: December 2020

In the last decades, precast prestressed hollow core slabs have gradually increased their market presence in many countries due to their excellent structural performance at room temperature. Longitudinal voids through the one way prestressed (or reinforced) concrete slabs are very important for reducing the self-weight of the structure. Although the hollow core precast concrete is larger than on-site placement concrete, when viewing the entire construction of the building as a whole, the use of hollow core precast concrete contributes more to the reduction of energy consumption than half-precast concrete or on-site placement concrete. Precast prestressed hollow core slabs are among to the more advanced structural floor systems for all kinds of buildings. This paper presents results from nonlinear numerical analysis of precast prestressed concrete hollow core slabs with dimensions 13,9m length, 1,19m width and 300mm thickness. Material properties obtained from testing of concrete (concrete cube strength) and 7 wire pre-stressing strands (yield strength) were used as input data for nonlinear simulation. The ATENA 3D FEM software was used for nonlinear numerical modelling. The results from numerical are compared with data from experimental investigation of a total 7 hollow core slabs.
Gradačac Old Town Complex - Current State Evaluation
Authors: Čaušević Amir , Rustempašić Nerman , Akšamija Lemja , Avdić Dženis
Published: December 2020

In the protection of historical heritage evaluating the current state of a facility is a very important phase since it provides for the project framework and the decision-making guidelines, which is all crucial for the final goal – protection of Gradačac Old Town complex. There are several historical layers encompassed by Gradačac Old Town - starting from the medieval fortification system, expanding to the Ottomans’ period where main buildings (a residential tower, a clock tower, and a mosque) were added by the Ottomans, extending and continuing the works on adding a library and a gymnasium in the Austro-Hungarian period. The overall Complex flows with the natural morphology of the terrain; nowadays these green areas are used as the main city park. Complex of Gradačac has two separate fortification zones, the main area of around 33 000 m2, and the accentuated part with the tower, of around 3 000 m2. The fortification (The Old Town) ground plan is approximately a square one, with sides from 180 to 200 m, consisting of the two main parts: The Lower and the Upper City. In the north-west area, there’s the Upper City (fortification inside the fortification, namely Husein-Captain Gradaščević’s Tower). The Old Town is accessed through three gates: The North (the main gate), the South, and the West gate. Upper City with Husein-Captain Gradaščević’s tower is positioned on the topmost point in the north side of the fortification complex. It rests on a terrace which encloses it from the south and the east side. On the north side of the Upper City, there are outer perimeter walls constituent to the whole of the Complex. Architectural heritage preservation and valorisation are increasingly important social and economic issue in many countries. The issues encountered in these undertakings range from defining and choosing required level of safety, via the question of electing methodologies relevant for contracting reliable structural analyses and safety check-ups, up to choosing the design and installation of suitable materials, and the intervention.
The Synergistic Effect of Secondary Raw Materials and Nano Additive on the Properties of Cement Matrix
Authors: Banevičienė Vilma , Malaiškienė Jurgita
Published: December 2020

The purpose of the research presented in this paper was to analyse the synergistic effect of nano SiO2 (NS), fluidized catalytic cracking catalyst waste (FCCCw) and calcinated at 700°C temperature paper sludge waste (PSw) on the properties the cement matrix. Nano materials are known to reduce voids between cement particles, accelerate cement hydration, and increase the strength of cement matrix. A certain amount of FCCCw and PSw in the cement mix also accelerates cement hydration and increase the compressive strength of the system, but it is important to analyse the synergistic effect of these materials on the properties of cement matrix. The results showed that both waste materials are active pozzolanic additives. The optimal quantities in terms of positive effect on the cement matrix are 10% of FCCCw and 2.5% of PSw. The paper presents the results of XRD analysis, density, ultrasonic pulse velocity and compressive strength tests with hardened cement paste. A 22% increase in compressive strength compared to the control specimen was observed in specimens where 10% of cement was replaced by FCCCw and where NS was additionally added. The replacement of cement by 2.5% of PSw increases the compressive strength about 7%. Moreover, the compressive strength of specimens containing 10% of FCCCw, 2.5% of PSw and NS increases even though the content of cement is reduced. Hardened cement paste specimens containing FCCCw, PSw, and NS have better density and ultrasonic pulse velocity values. XRD analysis showed that a combination of FCCCw, PSw, and NS added to the cement mix increases the amount of calcium hydrosilicates formed, reduces the amount of free portlandite and unreacted cement minerals (allite and belite).
Public Green Areas and their Devaluation in a Dense City Fabric of Sarajevo: Case Study of Hastahana Park
Authors: Krivošić Leila , Kljuno Alma Hudović
Published: December 2020

In a country that is still considered to be in the transitional period, even though the last war was more than two decades ago, the laws and legislations of the urban development with the focus on green areas, are loosely interpreted into reality in today’s Bosnia. The laws on urban planning and development stipulated in the time of former Yugoslav republic were precise in defining parameters in planning. In the former system, these laws were implemented resulting in string of great urban developments. Such big urban projects were executed all over former Yugoslavia in the late 1950s and1960s when industry grew and cities expanded and modernized. These urban projects included residential buildings, public buildings such as schools, kindergartens, municipality buildings, commercial areas as well as healthcare and recreational facilities including sports terrains and public green areas. The ratio between built and un- built was greatly respected leaving enough green spaces for leisure activities. Nowadays, the laws and regulations inherited from the former system are loosely interpreted or are being changed in favour of private investors at the cost of quality of life of cities’ inhabitants. This paper aims to explore the importance of green areas, or lack of the same, in urban developments within dense city fabric in the period of post war Bosnia focusing on current developments in Hastahana Park. The Park is located in popular and largely discussed area of Sarajevo’s Marijin Dvor, were recent urban developments characterized it as new business district of the city. Today, the remaining of Hastahana, the only public park on Marijin Dvor is endangered. Its future is uncertain because the site has been proclaimed, by the municipality authorities, as construction site. Despite attempts by citizens to stop sales and construction in the park area, city authorities ruled in their own favour (or in favour of fast money gain) versus welfare of citizens. The example of Hastahana Park shows that due to strong political pressures the norms and regulations can be changed, the need for big investments is stronger than the care for the need of citizens. While European cities stream to improve the amount of public green areas in cities contributing to healthier environment, at the same time, Sarajevo decreases valuable green areas in favour of giving advantage to construction, increasing already heavy traffic and air pollution in the city. Such reckless and irresponsible decisions have long-term impacts on city development and quality of life of its citizens.
Influence of Superficial Strengthening with FRCM System on Compressive Strength of Cracked AAC Masonry
Authors: Drobiec Lukasz , Mazur Wojciech , Jokiel Remigiusz
Published: December 2020

This paper describes results from studies on effects of superficial strengthening with FRCM system on compressive strength of autoclaved aerated concrete (AAC) masonry. Tests were carried out on models with one vertical crack and without crack. The research program included walls without any strengthening, strengthened at two or four sides. In addition, models with additional anchorage of superficial strengthening by steel plates were tested. Strengthened masonry did not demonstrate an increase of compressive strength and deformability. Increased deformability was observed for circumferentially strengthened masonry.
Application of the Virtual Reality Technology in Structural Safety Monitoring of Shield Tunnels
Authors: Ma Xinteng , Liu Yingchun , Wang Junwei , Wang Dan , Liu Yang
Published: December 2020

Many structural health monitoring (SHM) systems of actual tunnels are underused, with abstract data, chaotic information and the diagnostic results beyond comprehension. It is necessary to establish the visual connection between the visualization of monitoring network and massive structural information of tunnels. To address this issue, this study proposed a structural visualization method based on the panoramic virtual reality technology, combining the panoramic spherical image and the real-time monitoring data of tunnel obtained from SHM system. First, a software system for structural safety monitoring of an actual shield tunnel was developed on the basis of the combination of the panoramic visual technology and B/S (Browser/Server) architecture system. Second, the panoramic modelling method for specific tunnel structure environment was discussed in detail, and then the mechanism of data transmission and information access in panoramic virtual reality environment was investigated deeply. Finally, in view of the demands of practical application, the function modules of the abovementioned software system were described. Some key issues of how to develop each software module using the panoramic virtual reality technique were analysed e.g., online geographic information and cloud platform management. The results show that the panoramic virtual reality technology completely meets the needs of real-time processing, information management, virtual roaming and maintenance management in tunnel structural safety monitoring.
Determination of deformation characteristics of natural rock using methods of close-range photogrammetry
Authors: Brček Martin , Fraštia Marek , Ondrášik Martin , Kopecký Miloslav
Published: December 2020

In the field of civil engineering, traditional deformation sensors are used (measurements of changes of length and widths in the stressed material), such as an electrical resistance strain gauge, deviation meters (mechanical dial gauge, electronic digital indicator, LVDT). These sensors work quite well, but the sample surface preparation and fixing the sensors on the sample surface can be timely and work skill demanding. On the other hand, conventional non-destructive testing methods, such as rebound hammers or ultrasonic pulse propagation have a disadvantage in large data scatterness and low reliability. This paper focuses on a practical, more reliable and cost-effective method for determining deformation characteristics, calculated from digital images using the principle of close-range photogrammetry. To verify the effectiveness of this method, a test was performed on a sample of natural stone from the tunnel Višňové. The data were obtained by these methods and correlated with the used load. After plotting the stress-strain curve, the static modulus of elasticity and the modulus of deformation were determined. These modules were compared with those determined from resistance strain gauge measurements.
Reflections on Decanted Waste Water Application in the Timis County (Romania)
Authors: Grozav Adia , Rogobete Gheorghe
Published: December 2020

Livestock rearing in an enormous number on zootechnical piggery complexes is accompanied by a great quantity production of waste water, which needs a good management in order to turn to account and pollution control. At Timiş, county, level worked at the 1st January 2018 – 32 zootechnical piggery complexes, located in the plain zone, with a daily effective of 530,882 pigs. At an medium discharge of 30 l/head/day, results a daily volume of 15,926 m3 waste water which needs to be transported and stocked in a decanting pond. The positive aspect of this problem is the content of nutrients – about 2.3 g/l Ntotal, 0.07 g/l Ptotal and 0.7 g/l Ktotal, what means for all quantities of waste water a total quantity of nutrients of 36.6 tones N, 1.11 tones P and 11.15 tones K. Because to waste water contains also 62-72% C (relate to dry substance) through the biochemical decomposition at the soil surface, will be release 6370 m3 of carbon dioxide in the atmosphere, emission which contributes to the climate change. For this reason, there is absolutely necessary to application the decantated waste water by placement. Owing to the great diversity of the soils cover and the present the ground water layer at 1.0-1.5 m depth on a large area, it is necessary a permanent monitoring so as to avoid water and soil pollution with Na+, heavy metals or pathogens. The analytical data have been made for the Parţa territory from Timiş county, in the years 2015 -2016 -2017 and were compared with a soil survey achieved in the year 2010.