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1
Jara, J. M., B. A. Olmos, M. Jara i W. M. Conejo. "RC jacketing parameters to retrofit highway bridges". Bulletin of Earthquake Engineering 14, nr 10 (15.04.2016): 2859–80. http://dx.doi.org/10.1007/s10518-016-9914-7.
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Cai, Bin, i Xin Hui Liu. "Research on Parameters of RC Structure Reliability". Applied Mechanics and Materials 501-504 (styczeń 2014): 1061–64. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.1061.
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In the analysis of engineering structures are usually adopt the method of fixed value, that is the practical engineering structure under load and the performance of materials used by structure shall be treated as a constant value.But, in fact, the structure of geometry size, bear the load, material parameters,computing model and so on are affected by various factors. In order to more accurately reflect the reliability problems of reinforced concrete structures, this paper, the factors above will be regarded as random variables, combining the basic theory of reliability design, through the probability analysis, in normal uselimit state reliability of reinforced concrete structures for example analysis of the influence of related parameters on the structural reliability.
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Lin, Che-Yu. "Ramp-Creep Ultrasound Viscoelastography for Measuring Viscoelastic Parameters of Materials". Materials 13, nr 16 (14.08.2020): 3593. http://dx.doi.org/10.3390/ma13163593.
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Several ultrasound-based methods have been developed to evaluate the viscoelastic properties of materials. The purpose of this study is to introduce a novel viscoelastography method based on ultrasound acoustic radiation force for measuring the parameters relevant to the viscoelastic properties of materials, named ramp-creep ultrasound viscoelastography (RC viscoelastography). RC viscoelastography uses two different ultrasound excitation modes to cause ramp and creep strain responses in the material. By combining and analyzing the information obtained from these two modes of excitation, the viscoelastic parameters of the material can be quantitatively evaluated. Finite element computer simulation demonstrated that RC viscoelastography can accurately evaluate the viscoelastic parameters of the material, including the relaxation and creep time constants as well as the ratio of viscous fluids to solids in the material, except for the region near the top surface of the material. The novelty of RC viscoelastography is that there is no need to know the magnitude of acoustic radiation force and induced stress in the material in order to evaluate the viscoelastic parameters. In the future, experiments are necessary to test the performance of RC viscoelastography in real biomaterials and biological tissues.
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Wang, Xiao Dong, Xie Dong Zhang i Jin Zhi Wang. "Study on Fire Resistance Design Parameters of RC Structure". Advanced Materials Research 295-297 (lipiec 2011): 183–88. http://dx.doi.org/10.4028/www.scientific.net/amr.295-297.183.
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By analyzing the randomicity and sensitivity of design parameters on fire resistance performance of RC structure, it indicates that the concrete thickness of covering layer is the most sensitive parameter to RC fire resistance performance in all given out parameters. And the stochastic finite element reliability analyzing method is briefly introduced too.
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Radu, Lucretiu, Mara Carsote, Anca Mihaela Predescu, Tiberiu Stefanita Tenea Cojan, Bogdan Socea, Vlad Dumitru Baleanu, Mihaela Popescu, Nina Ionovici i Dana Maria Albulescu. "Biochemical Parameters in Patients Using Teriparatide". Revista de Chimie 69, nr 12 (15.01.2019): 3483–85. http://dx.doi.org/10.37358/rc.18.12.6774.
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Teriparatide (TPT) is the active 1-34 amino acid sequence with osteoanabolic use for severe osteoporosis. Our aim is to analyze the biochemical and clinical profile of patients treated with TPT based on Romanian protocol. The inclusion and exclusion criteria are based on specific country protocol for TPT 20 �g/day, for 2 years, once in life time based on self administration. This is a transversal study including data of a tertiary centre of endocrinology on patients who signed the informed consent. This is a real life study, of observational type (the intervention meaning the TPT recommendation was done by individual decision of each clinician). Normal total and ionic calcium is associated with low 25-hydroxyvitamin D levels and a mean lumbar T-score of -3.1�0.7SD. 50% of patients treated with TPT have digestive conditions, less than 10% are first time users, a high severity profile is based on a median of 4 years regarding prior anti-osteoporotic medication and of 3 previous fragility fractures.
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Han, Sang Whan, Chang Seok Lee, Mary Ann Paz Zambrana i Kihak Lee. "Calibration Factor for ASCE 41-17 Modeling Parameters for Stocky Rectangular RC Columns". Applied Sciences 9, nr 23 (29.11.2019): 5193. http://dx.doi.org/10.3390/app9235193.
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Existing old reinforced concrete (RC) buildings could be vulnerable to large earthquake events. Most columns in such buildings have insufficient reinforcement details, which may experience failure during an early loading stage. The failure of columns may lead to partial or complete collapse of entire building systems. To prepare for an adequate retrofit plan for columns, it is necessary to simulate the cyclic behavior of columns using a numerical model with adequate values of constituent modeling parameters. The nonlinear component modeling parameters are specified in ASCE 41-17. However, the experiments on stocky RC columns suggest that ASCE 41-17 nonlinear component modeling parameters do not reflect the RC column behavior adequately. To accurately simulate the nonlinear load–deformation responses of stocky RC columns with low span-to-depth ratio, this study proposes a calibration factor for ASCE 41-17 RC column modeling parameters. For this purpose, this study collected test data of 47 stocky column specimens. Based on the test data, empirical equations including the calibration factor for modeling parameters “a” and “b” in ASCE 41-17 were proposed. The accuracy of the proposed equation was verified by comparing the measured and calculated envelope curves.
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Verma, Sanjeev Kumar, Sudhir Singh Bhadauria i Saleem Akhtar. "Probabilistic Evaluation of Service Life for Reinforced Concrete Structures". Chinese Journal of Engineering 2014 (18.02.2014): 1–8. http://dx.doi.org/10.1155/2014/648438.
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Degradation of performance and deterioration of different components of reinforced concrete (RC) structures increase with the age of structure. This deterioration of reinforced component depends on several parameters. However, modeling service life of RC structure by considering all the parameters is a difficult job, as most of the parameters are uncertain in nature. Probabilistic models account well for the uncertainties in the parameters responsible for deterioration of RC structures. This paper presents a review of several recent service life models developed using probability based concepts.
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Xiang, Kai, Guo Hui Wang i Bi Zhao. "Finite Element Analysis of Shear Strength of Reinforced Concrete Beams after Fire". Advanced Materials Research 671-674 (marzec 2013): 474–78. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.474.
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Shear strength and stiffness of fire-damaged reinforced concrete (RC) beams were researched. The nonlinear finite element method (FEM) was developed to simulate shear strength of fire-damaged RC beams. Considering mechanical properties deterioration of concrete and steel reinforcing bar, the parameters of fire-damaged RC beams, including fire exposure time, shear span to depth ratios, concrete strength, diameters of stirrups and spacing of stirrups, were analyzed. Based on numerical analysis, the change of shear strength and stiffness of fire-damaged RC beams were identified. The results showed that shear strength and stiffness of fire-damaged RC beams changed under different parameters. With increase of fire exposure time or increase of shear span to depth ratio or decrease of concrete strength, shear strength and stiffness of fire-damaged RC beams descended obviously. With decrease of diameters of stirrups or increase of spacing of stirrups, shear strength of fire-damaged RC beams descended gradually, but stiffness of fire-damaged RC beams had little change.
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Butyrskaia, I. "HYGIENIC EVALUATION OF PRE-CONSCRIPTION AGE YOUNG MEN’ MORPHOPHYSIOLOGICAL PARAMETERS IN THE CRIMEA". Tavricheskiy Mediko-Biologicheskiy Vestnik 23, nr 1 (18.10.2022): 15–19. http://dx.doi.org/10.29039/2070-8092-2020-23-1-15-19.
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The paper is dedicated to age trends among young men of pre-draft age in the Republic of Crimea (RC). To define health condition, we examined 380 young men of 14-16 years old, who studied in board-schools in different areas of RC. They live in different conditions minimizing impact of extra-school medium. Physiometric measurements (height, body mass, chest circumference, muscular power, pulse rate, lung capacity) were taken with standard methods, mean arterial pressure was counted by Hickam formula, output volume – by Starr formula. One showed that in RC they observe common Russian trend of worsening adolescents’ health. As age increased health parameters are stabilized, and by the time of graduation from school approach to standards. The level of acute morbidity still remains high. Among chronic diseases in RC in pre-draft age young men diseases of respiratory, urogenital and nervous systems dominate. They have to find possibilities on youth sanitation from all the sides dealing with it: state administration, draft boards, school, and family.
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Chen, Jing, Yuping Chen, Anmei Shu, Jinfu Lu, Qiu Du, Yuwei Yang, Zhiyang Lv i Huiqin Xu. "Radix Rehmanniae and Corni Fructus against Diabetic Nephropathy via AGE-RAGE Signaling Pathway". Journal of Diabetes Research 2020 (2.12.2020): 1–15. http://dx.doi.org/10.1155/2020/8358102.
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Background and Aims. Radix Rehmanniae and Corni Fructus (RC) have been widely applied to treat diabetic nephropathy (DN) for centuries. But the mechanism of how RC plays the therapeutic role against DN is unclear as yet. Methods. The information about RC was obtained from a public database. The active compounds of RC were screened by oral bioavailability (OB) and drug-likeness (DL). Gene ontology (GO) analysis was performed to realize the key targets of RC, and an active compound-potential target network was created. The therapeutic effects of RC active compounds and their key signal pathways were preliminarily probed via network pharmacology analysis and animal experiments. Results. In this study, 29 active compounds from RC and 64 key targets related to DN were collected using the network pharmacology method. The pathway enrichment analysis showed that RC regulated advanced glycosylation end product (AGE-) RAGE and IL-17 signaling pathways to treat DN. The animal experiments revealed that RC significantly improved metabolic parameters, inflammation renal structure, and function to protect the kidney against DN. Conclusions. The results revealed the relationship between multicomponents and multitargets of RC. The administratiom of RC might remit the DM-induced renal damage through the AGE-RAGE signaling pathway to improve metabolic parameters and protect renal structure and function.
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Cambrea, Simona Claudia, Elena Dumea, Lucian Cristian Petcu, Cristina Maria Mihai, Constantin Ghita, Loredana Pazara, Diana Badiu i in. "Fetal Growth Restriction and Clinical Parameters of Newborns from HIV-Infected Romanian Women". Medicina 59, nr 1 (5.01.2023): 111. http://dx.doi.org/10.3390/medicina59010111.
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Background and Objectives: The present study assessed the fetal growth restriction and clinical parameters of both human immunodeficiency virus (HIV)-negative and HIV-positive newborns from HIV-infected mothers in two HIV-acquired immunodeficiency syndrome regional centers (RCs) in Constanta and Craiova, Romania, in order to evaluate the adverse birth-related outcomes. Materials and Methods: These represent a retrospective study conducted between 2008 and 2019, in which 408 pregnant HIV-positive women, 244 from Constanta RC and 164 from Craiova RC, were eligible to participate in the study. Consecutive singleton pregnancies delivered beyond 24 weeks of pregnancy were included. Growth restriction in newborns was defined as the birth weight (BW) being less than the third percentile, or three out of the following: BW < 10th percentile; head circumference (HC) < 10th percentile; birth length (BL) < 10th percentile; prenatal diagnosis of fetal growth restriction; and maternal pregnancy information. Of the 244 newborns delivered in Constanta, RC, 17 were HIV-positive, while in Craiova, RC, of the 164 newborns, 9 were HIV-positive. All HIV-positive women were on combined antiretroviral therapy (cART) during pregnancy, similar to all HIV-positive newborns who received ARTs for the first six weeks. We search for the influence of anthropometrical parameters (i.e., HC, BL, and BW), as well as clinical parameters (i.e., newborn sex and Apgar score) for both HIV-negative and HIV-positive newborns, along with the survival rate of HIV-positive newborns. Results: There were no differences in the sex of the newborns within either group, with more than 50% being boys. Similarly, the Apgar score did not show any statistically significant values between the two groups (i.e., p = 0.544 for HIV-positive newborns vs. p = 0.108 for HIV-negative newborns). Interestingly, our results showed that in Craiova, RC, there was a chance of 2.16 to find an HIV-negative newborn with an HC < 10th percentile and a 2.54 chance to find an HIV-negative newborn with a BL < 10th percentile compared to Constanta, RC, without any significant differences. On the contrary, Constanta, RC, represented a higher risk of death (i.e., 3.049 times, p = 0.0470) for HIV-positive newborns compared to Craiova, RC. Conclusions: Our results support the idea that follow-up of fetal growth restriction should be part of postnatal care in this high-risk population to improve adverse birth-related outcomes.
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Tamrazyan, Ashot G., i Yehia A. K. Sayed. "Predicting the Strength of Rectangular Reinforced Concrete Columns Confined with FRP Sheets". Key Engineering Materials 906 (11.01.2022): 17–23. http://dx.doi.org/10.4028/www.scientific.net/kem.906.17.
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A complete reorganization about the behavior of rectangular RC columns confined with FRP sheet is very important to predict the axial compressive strength values of the strengthened rectangular RC columns. That is because the process of strengthening RC rectangular column depending on several parameters that role this type of strengthening. These parameters include the characteristics of the used fiber, the grade of concrete and the geometry of the cross section including the rectangularity aspect ratio, corner radius, and size of specimens. Besides that, using a wide scope of experimental data may affect positively to generalize a model that considers the whole parameters affect the value of the axial strength. So, in this paper a review about parameters that affect the axial compressive strength values of rectangular RC columns was conducted. After that, based on the test results regarding FRP-confined rectangular RC columns available in the literature or conducted by the author, some existing confinement models for rectangular RC columns were assessed. Further, a new model is proposed through regression analysis of the database. A new model is proposed through regression analysis of the database. The proposed model was found to be in good agreement with the test results in the database. Finally, based on the results conclusions were drawn.
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Foroughi, Saeid, i S. Bahadir Yuksel. "Effective flexural stiffness for reinforced concrete shear walls having confined boundary elements". Journal of Structural Engineering & Applied Mechanics 4, nr 2 (30.06.2021): 126–39. http://dx.doi.org/10.31462/jseam.2021.04126139.
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In the design of reinforced concrete (RC) shear walls strength, ductility and effective stiffness of the elements must be taken into account and are important parameters in terms of structural safety. Accurate estimation of the ductility and effective stiffnesses of RC members has always been an attractive subject of study as it provides a reliable estimate of the capacity of buildings under seismic loads. In this study, RC shear wall models with different concrete strength, longitudinal and transverse reinforcement ratios were designed to investigate effective section stiffness and coefficients. The effective stiffness of the cracked section in the RC shear walls designed in different parameters were analytically obtained. Analytically investigated parameters were calculated from TBEC (2018), ACI318 (2014), ASCE/SEI41 (2017) and Eurocode8 (2004, 2005) regulations and nonlinear behaviors. The results obtained according to different design parameters were compared and examined. In the relations suggested for the effective section stiffness coefficient, the confining effect is not taken into account as in the regulations. Therefore, it means neglecting the effects of parameters such as concrete strength, confining effect and axial load levels acting on the section. This situation can lead to unrealistic results in the design and evaluation of RC elements. For this reason, determining the moment-curvature relationship in the design and evaluation of RC elements and obtaining effective section stiffness values are of great importance in order to obtain more realistic results.
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Neagu, Anisoara-Arleziana, Alina Soceanu i Semaghiul Birghila. "Analysis of Soils Parameters in Correlation with Vegetation Period". Revista de Chimie 71, nr 9 (5.09.2020): 210–20. http://dx.doi.org/10.37358/rc.20.9.8331.
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Soil is a complex ecosystem whose functionality is related to the links that exist between chemical, physical, biological parameters and microbial communities. Our purpose was to carry out an analysis of variance of chemical properties of the soil in relation to the vegetation period. The analysis of the soil gives us knowledge about the fertility status of the soil, which is closely related to the nutritional status of plants. The analysis involved urban soil, agricultural soil and greenhouse soil from Dobrogea area. Soil samples come from the urban area: Constanta, agricultural area: Ciocarlia de Sus and greenhouse:Cumpana. To estimate the seasonal changes in the soil, three periods were studied: before vegetation (sowing), after the vegetation period (harvesting), relative rest period (winter). The chemical parameters evaluated were: soil reaction pH (acidity degree), conductivity - as an indicator of the nutrients available in the soil (soluble salts), ion exchange capacity (cations and anions), organic matter (humus), nitrogen content (total nitrogen and nitrites), the amount of extractable iron. The pH values were in the range corresponding to the weak acid-neutral soil for all three types of sample soils, with slight variations from one period to another while the recorded conductivity values indicate that the analyzed soils belong to the category of non-saline soils. The analyzed soil samples presented low concentrations of nitrites and the assimilable iron content was in the range 48.81 - 259.12 ppm.
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Uzdil, Oğuz, Barış Sayın i Turgay Coşgun. "Examination of parameters impacting flexural and shear strengthening of RC beams". Journal of Structural Engineering & Applied Mechanics 5, nr 3 (30.09.2022): 117–34. http://dx.doi.org/10.31462/jseam.2022.03117134.
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Structural performance of reinforced concrete (RC) structures should be improved due to new design standards, strength reduction, and/or functional changes throughout their service life. To reach a sufficient level of structural performance, the following two options can be considered: reconstruction or strengthening of structures. Although reconstruction has some advantages in terms of using current technological developments, this option can lead to some negative consequences such as interruption of the building's service life, relatively high cost, and sustainability issues. Therefore, strengthening an existing structure mostly stands out as the first choice. The techniques used in strengthening applications can be grouped into two different methods: traditional (addition of new structural members) and non-conventional (seismic base isolation, local retrofitting, and jacketing). Among innovative methods, the fibre-reinforced polymer strengthening method attracts attention due to several advantages including practical applicability, as well as shear and bending capacity increase. Its application to the outer surface of structural members using resin reduces deterioration. Plus, fibres oriented in various directions spread stresses in different directions, therefore, provide effective force distribution. In this study, the effect of carbon fibre reinforced polymer (CFRP) orientation and RC material properties in the strengthening RC beams were investigated using MATLAB software. Accordingly, all stages of the design process are presented for RC beam strengthening considering both flexural and shear effects based on the American Concrete Institute (ACI) 440.2R standard. Through compiling MATLAB code, calculation time reduces, and material characteristics can be obtained more accurately. Plus, using curves obtained by MATLAB coding, shear and bending capacity increases can be observed. According to our findings, the application of one-layer CFRP plate to an RC beam increases the bending capacity by 50.6% and shear capacity by 33.6%. However, as the number of layers increases, the capacity increase rate reduces.
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Zheng, Shan Suo, Qing Lin Tao, Yi Hu i Zhi Qiang Li. "Damage Sensitivity Analysis for Main Design Parameters of Reinforced Concrete Shear Wall". Advanced Materials Research 374-377 (październik 2011): 2574–77. http://dx.doi.org/10.4028/www.scientific.net/amr.374-377.2574.
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As an indispensable force component to the hybrid structure, the seismic wave energy inputted into integral structure is dissipated by damping force working and plastic hysteresis of reinforced concrete shear wall which is taken as the first seismic fortification line of structure. Considering of the condition that the RC shear wall is mainly used to dissipate the seismic wave energy, this paper takes the ultimate energy dissipation capacity of reinforced concrete shear wall subjected to cyclic loading as the damage characterization. According to the related theoretical analysis and experimental research, the method for calculating ultimate energy dissipation capacity of RC shear wall is proposed and the damage sensitivity of various design parameters which contain the sectional thickness, the strength of concrete and reinforcement ratio are analyzed, then the influence laws of main design parameters impacted on damage evolution of RC shear wall are revealed in this paper. The research shows that sectional thickness is the most sensitive factor in the damage of reinforced concrete shear wall and the concrete strength degree takes the second place, and then the reinforcement ratio is the most insensitive design parameter. The research achievements will provide theoretical support for establishing the storey damage model of SRC frame-RC core wall hybrid structure under seismic excitation.
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Dan, Wenjiao, Xinxin Yue, Min Yu, Tongjie Li i Jian Zhang. "Prediction and Global Sensitivity Analysis of Long-Term Deflections in Reinforced Concrete Flexural Structures Using Surrogate Models". Materials 16, nr 13 (28.06.2023): 4671. http://dx.doi.org/10.3390/ma16134671.
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Reinforced concrete (RC) is the result of a combination of steel reinforcing rods (which have high tensile) and concrete (which has high compressive strength). Additionally, the prediction of long-term deformations of RC flexural structures and the magnitude of the influence of the relevant material and geometric parameters are important for evaluating their serviceability and safety throughout their life cycles. Empirical methods for predicting the long-term deformation of RC structures are limited due to the difficulty of considering all the influencing factors. In this study, four popular surrogate models, i.e., polynomial chaos expansion (PCE), support vector regression (SVR), Kriging, and radial basis function (RBF), are used to predict the long-term deformation of RC structures. The surrogate models were developed and evaluated using RC simply supported beam examples, and experimental datasets were collected for comparison with common machine learning models (back propagation neural network (BP), multilayer perceptron (MLP), decision tree (DT) and linear regression (LR)). The models were tested using the statistical metrics R2, RAAE, RMAE, RMSE, VAF, PI, A10−index and U95. The results show that all four proposed models can effectively predict the deformation of RC structures, with PCE and SVR having the best accuracy, followed by the Kriging model and RBF. Moreover, the prediction accuracy of the surrogate model is much lower than that of the empirical method and the machine learning model in terms of the RMSE. Furthermore, a global sensitivity analysis of the material and geometric parameters affecting structural deflection using PCE is proposed. It was found that the geometric parameters are more influential than the material parameters. Additionally, there is a coupling effect between material and geometric parameters that works together to influence the long-term deflection of RC structures.
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Hu, Jinzhu, Manchao He, Jiong Wang, Zimin Ma, Yajun Wang i Xingyu Zhang. "Key Parameters of Roof Cutting of Gob-Side Entry Retaining in a Deep Inclined Thick Coal Seam with Hard Roof". Energies 12, nr 5 (11.03.2019): 934. http://dx.doi.org/10.3390/en12050934.
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Gob-side entry retaining by roof cutting (GERRC) employed in a deep inclined thick coal seam (DITCS) can not only increase economic benefits and coal recovery, but also optimize surrounding rock structure. In accordance with the principles of GERRC, the technology of GERRC in DITCS is introduced and a roof-cutting mechanical model of GERRC is proposed to determine the key parameters of the depth and angle of RC. The results show that the greater the RC angle, the easier the caving of the goaf roof, but the length of cantilever beam increases. The depth of RC should account for the dip angle of the coal seam when the angle is above 20°. Increasing the coal seam dip angle could reduce the volume of rock falling of the goaf roof, but increase the filling height of the upper gangue to slide down. According to numerical model analysis of the stress and displacement of surrounding rock at different depths and angles of RC, when the depth of RC increased from 9 m to 13 m, the distance between the stress concentration zone and the coal side is increased. When the angle of RC increased from 0° to 20°, the value of roof separation is decreased. GERRC was applied in a DITCS with 11 m depth and 20° RC angle, and the field-measured data verified the conclusions of the numerical model.
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Hasanzadeh, Behzad, Yousef Abbaspour-Gilandeh, Araz Soltani-Nazarloo, Eduardo De La Cruz-Gámez, José Luis Hernández-Hernández i Miriam Martínez-Arroyo. "Non-Destructive Measurement of Quality Parameters of Apple Fruit by Using Visible/Near-Infrared Spectroscopy and Multivariate Regression Analysis". Sustainability 14, nr 22 (11.11.2022): 14918. http://dx.doi.org/10.3390/su142214918.
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The quality assessment and grading of agricultural products is one of the post-harvest activities that has received considerable attention due to the growing demand for healthy and better-quality products. Recently, various non-destructive methods have been used to evaluate the quality of agricultural products, which are very desirable and faster and more economical than destructive methods. Optical methods are one of the most important non-destructive methods that use the high speed of light detection and computer data processing and are able to evaluate the quality and classification of products with high accuracy. Among the optical methods, visible–near-infrared (Vis/NIR) spectroscopy is considered one of the most accurate methods. In this research, Vis/NIR spectroscopy technology was used in the spectral range of 350–1150 nm for non-destructive detection of some quality parameters including pH, TA, SSC, and TP of two varieties of Red Delicious and Golden Delicious apples. Various pre-processing models were developed to predict the parameters, which brought the desired results with high accuracy so that pH prediction results were for yellow apples (RMSEC = 0.009, rc = 0.991, SDR = 2.51) and for red apples (RMSEC = 0.005, rc = 0.998, SDR = 2.56). The results for TA were also (RMSEC = 0.003, rc = 0.996, SDR = 2.51) for red apples and (RMSEC = 0.001, rc = 0.998, SDR = 2.81) for yellow apples. The results regarding SSC were for red apples (RMSEC = 0.209, rc = 0.990 and SDR = 2.82) and for yellow apples (RMSEC = 0.054, SDR = 2.67 and rc = 0.999). In addition, regarding TP, the results were for red apples (RMSEC = 0.2, rc = 0.989, SDR = 2.05) and for yellow apples (RMSEC = 1.457, rc = 0.998, SDR = 1.61). The obtained results indicate the detection of the mentioned parameters with high accuracy by visible/infrared spectroscopic technology.
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Durajski, A. P., i R. Szczȩśniak. "Estimation of the superconducting parameters for silane at high pressure". Modern Physics Letters B 28, nr 07 (13.03.2014): 1450052. http://dx.doi.org/10.1142/s0217984914500523.
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The properties of the superconducting state in the Cmca phase of silane ( SiH4 ) at the pressure of 250 GPa have been considered. In particular, the critical temperature (TC), the free energy difference between the superconducting and normal state (ΔF ≡ FS - FN), the thermodynamic critical field (HC) and the specific heat jump (ΔC ≡ CS - CN) have been determined. It has been shown that the dimensionless ratios: [Formula: see text] and RC ≡ ΔC(TC)/CN(TC) assume the values: RH(μ⋆) ∈ 〈0.147, 0.154〉 and RC(μ⋆) ∈ 〈2.20, 1.79〉, where the symbol μ⋆ denotes the Coulomb pseudopotential and μ⋆∈ 〈0.1, 0.3〉.
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Giuroiu, Cristian Levente, Sorin Andrian, Aurelian Sorin Pasca, Ana Maria Fatu i Mihai Bogdan Vascu. "Assessment of Physical and Chemical Parameters of Four Endodontic Sealants". Revista de Chimie 69, nr 9 (15.10.2018): 2443–47. http://dx.doi.org/10.37358/rc.18.9.6550.
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The endodontic sealants have an essential role in the root canal filling. The aim of this study was to analyse and compare three physio-chemical properties (pH, solubility, viscosity). The most significant decrease of the viscosity was for MTA-Fillapex, followed by Endoflas FS and Acroseal. The best behavior was recorded for Endomethasone N. The total decrease of dry mass (reported to baseline) was 0.0113 for Acroseal. Endoflas FS had a total decrease of dry mass of 0.0377 (from 0,6864 to 0.6487) during the study. The total decrease of dry mass (reported to baseline) was 0.0047 for Endomethasone N. MTA Fillapex had a total decrease of 0.0226 (from 0.4805 to 0.4579) during the study period. MTA Fillapex had the highest pH values (pH 10.16), followed by Acroseal (pH 8.79), Endoflas FS (pH 7.98) and Endomethasone N (pH 7.73).
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Gritco-Todirascu, Antonina, Dorina Emilia Creanga, Liliana Mihaela Ivan, Dana Ortansa Dorohoi i Anamaria Ciubara. "New QSAR and Solvatochromic Estimation of Molecular Parameters of Chlortetracycline". Revista de Chimie 71, nr 2 (3.03.2020): 121–27. http://dx.doi.org/10.37358/rc.20.2.7904.
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The present paper is focused on determination of the main parameters of Chlortetracycline. Chlortetracycline belongs to one of the most used family of antibiotics worldwide, Tetracyclines. Because of the large spectrum of infections which can be treated with this category of antibiotics there are attempts to find new derivatives from this class. The compounds derived from the same basic structure exhibit same chemical properties, that is why knowing in detail the main physico-chemical properties of Chlortetracycline could be a real help in synthesize new efficient derivatives. In order to evaluate the reactivity and biological activity HyperChem was used to establish the optimized structure, the electro-optical, the energetic and QSAR parameters. The solvatochromic methods allowed determining the intermolecular interactions types and their contribution to the spectral shifts of measured electronic absorption bands. Based on computational and solvatochromic results, the excited state dipole moment of Chlortetracycline was established by variation method.
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Crisan, Adrian, Ovidiu Mitu, Irina Iuliana Costache, Radu Miftode, Cristian Mihai Stefan Haba, Ivona Mitu, Daniela-Cristina Dimitriu i Antoniu Octavian Petris. "The Assessment of Biochemical Parameters in Patients with Venous Thromboembolism". Revista de Chimie 71, nr 4 (5.05.2020): 594–600. http://dx.doi.org/10.37358/rc.20.4.8100.
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Assessing the biochemical parameters in patients with pulmonary embolism (PE), deep vein thrombosis (DVT) or both brings complimentary information for the cardiovascular (CV) and death risk stratification. The purpose of the study was to evaluate the association between biochemical parameters and PE, DVT or both. The study was prospective, conducted over a 12-month period and included 151 patients diagnosed with PE, DVT or both pathologies. These patients were extensively analysed taking into account biochemical parameters associated with the above-mentioned pathologies. Mean age was 59.23 � 18.22 years and 55% were women. 38.40% patients had PE, 48.30% had DVT and 13.20% had both pathologies. GFR upon admission was strongly negatively associated with age, r(148)= -0.75, p[0.01, intra-hospital death r(148)= -0.18, p=0.02 and with AST levels r(144)= -0.21, p=0.01 and positively statistically significant with the number of days of hospitalization r(8)= +0.79, p=0.0. Moreover, for one unit decrease in GFR the number of days of hospitalization decreased with 0.231. Moreover, AST correlated with intra-hospital death r(146)= 0.25, p[0.01, creatinine upon admission r(144)= 0.24, p[0.01, urea upon admission r(143)= 0.16, p=0.04 and glucose levels r(139)= 0.19, p=0.02, but negatively associated with GFR upon admission with r(144)= -0.21, p=0.01; for each one unit decrease of GFR there was an increase in AST levels by 0.21. Also there was a significant correlation between the thrombolysis therapy and the number of days of hospitalization r(151)= 0.21, p[0.01 and between positive inotropic support and intra-hospital death with r(151)= 0.27, p[0.01. In patients with PE, DVT or both, renal function, AST levels and the number of days of hospitalization were associated with an increased risk of death, especially in patients with PE � DVT.
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Mihalache, Sanda Florentina, i Madalina Carbureanu. "The Factorial Analysis of the Activated Sludge Treatment Process Parameters". Revista de Chimie 71, nr 5 (29.05.2020): 75–85. http://dx.doi.org/10.37358/rc.20.5.8115.
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The main environmental problems comprise two main directions: air and water. Water treatment plant is a critical infrastructure, especially in large cities. The activated sludge process is a typical example of highly nonlinear system. The associated models found in literature are mainly analytical and complex. In this paper there are proposed data-driven models obtained from plant operation data. A factor reduction procedure, namely principal component analysis is used to find meaningful correlations between process measurements. The selected correlations are obtained via simple and multiple regression algorithm. The resulted models are specific to the studied plant, simpler than the analytical ones, and with sufficient accuracy if used in plant monitoring and operation. The proposed procedure of using data-driven models for inferential measuring decreases the analysis costs (even eliminating the necessity of measuring equipment). If the experience in operating the plant is used to predict parameter trends this procedure can provide a useful tool for developing a decision support system for the plant operator. A real time prediction module associated with a warning system can be applied for every active sludge process, having as condition the availability of plant operating data.
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Gurin, Andrey, Yelena Chakrova, Ilona Matveyeva i Patrick Riss. "Optimization of Reaction Parameters for the Synthesis of 177Lu-DOTAELA". Revista de Chimie 71, nr 8 (31.08.2020): 55–62. http://dx.doi.org/10.37358/rc.20.8.8278.
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The article provides a comparison of the theoretically calculated and experimentally determined yield of the reaction 176Lu (n, �A)177Lu. Also, it provides the results of the studies on lutetium-177 labeling of a non-peptide antagonist of gonadotropin-releasing hormone (GnRH) elagolix (ELA) associated with a chelating DOTA (DOTAELA). The synthesized DOTAELA complex was labeled with the 177Lu isotope.177Lu was produced by the reaction (n, �A) using the enriched LuCl3 target at the reactor WWR�CK. Production of 177Lu by the (n, �A) reaction from the enriched 176Lu target achieved by irradiation for 17 days. All stages of the complex preparation were evaluated by paper chromatography. The optimal technological parameters for the synthesis of the complex 177Lu-DOTAELA are: pH - 4.5, 90-100 �aC and 40 min. The obtained optimal parameters made it possible to produce a labeled complex of 177Lu�CDOTAELA with a radiochemical yield of �Y 95%.
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Buzatu, Roxana, Smaranda Laura Gotia, Anca S. Valceanu, Ioana Scrobota, Doina Onisei i Camelia Szuhanek. "The Dynamics of Salivary Parameters in Patients Undergoing Orthodontic Treatment". Revista de Chimie 68, nr 3 (15.04.2017): 515–17. http://dx.doi.org/10.37358/rc.17.3.5491.
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From assisting in digestion and lubricating soft tissues to neutralizing plaque and promoting tooth remineralization, saliva is crucial to the oral environment. Our objective was to analyze the dynamics of salivary parameters in patients with orthodontic treatment. Subjects were divided into two age-related groups. Results showed an increase in the number of epithelial cells and leukocytes, as well as various changes in glutathione and C-reactive protein levels. Another significant finding was that young people were more prone to developing oral candidiasis after receiving a fixed orthodontic appliance.
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Ma, De Yun, Yong Zhi Zuo, Da Huo i Hai Wen Teng. "Sensitivity Study of RC Columns’ Reliability to Random Parameters". Key Engineering Materials 400-402 (październik 2008): 477–82. http://dx.doi.org/10.4028/www.scientific.net/kem.400-402.477.
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The value of sensitive factors in structural reliability analysis greatly affects reliability calculation results. These factors must be accurately determined and studied to improve the accuracy of calculated results. Based on the analysis of existing sensitivity calculation methods, a new practical sensitive factor analysis method was put forward to analyzing sensitive factors in structural strength reliability calculations. The dimensionless sensitive indexes of structural reliability were defined in the new method to compare the influence degree of random parameters to reliability. And the method was applied to analyze sensitivity under the two conditions of the structural resistance decreasing and not changing with time. Random variables, defined by their probability distribution and corresponding distribution parameters, were used to describe uncertainties in the reliability calculation. Different forced state RC columns were taken as examples to analyze the structural sensitivity, and sensitive factors affecting the columns’ structural reliability were obtained. The results show that the reliability of time-varying structure has descended to some extent compared with that without time-varying structure, and the effect from the random parameters to reliability index. The example and theory demonstrate the feasibility and rationality of the new method. This article has certain reference value to the structural design, construction and detection.
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Pavel, Florin, i Andrei Pricopie. "Prediction of engineering demand parameters for RC wall structures". Structural Engineering and Mechanics 54, nr 4 (25.05.2015): 741–54. http://dx.doi.org/10.12989/sem.2015.54.4.741.
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Bo, Kun, Mao Sen Wang i Zhi Qiang Zhao. "Numerical Simulation on Bottom Hole Flow Fields of Reverse Circulation Bit". Applied Mechanics and Materials 256-259 (grudzień 2012): 2826–30. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.2826.
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Air reverse circulation (RC) drilling is becoming an increasingly popular technique in engineering fields. It can be used in geological exploration, water well drilling and infrastructure construction and so on. RC bit is the key accessory in this technique. Its structural parameters directly influence cutting transportation during reverse circulation drilling. In order to explain the formation mechanism of reverse circulation, established mathematical models and physics model of the RC bit and studied drilling fluids transportation under the bottom hole. Conducded numerical simulation about velocity field and pressure field of bottom hole flow field using software FLUENT with different parameters of the RC bit, including the size and position of nozzles, the angle of inner nozzle and so on. The result of simulation and experiment show that increase of the effective turbulence zone can improve efficiency of RC transportation. Inner nozzles can produce stable negative pressure region in the central channel, and ensure cutting transportation as RC methods. The data and results are helpful to optimize the structure and size of the RC bit. It can shorten the research period, decrease costs and improve the design ability.
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Mohamed, Ghada R., Nevin Ahmed, Rokayya Sami, Ahmed M. A. Mansour, Nibal A. Hassan, Nada Benajiba i Moamen A. Elbath. "Noxiousness Valuation of Two Pharmaceutical Plants on White Garden Snail and Their Side Influences on Biochemical Parameters and Histopathological Changes in Brown Rat". Journal of Biobased Materials and Bioenergy 16, nr 1 (1.02.2022): 127–34. http://dx.doi.org/10.1166/jbmb.2022.2152.
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The current study aimed to evaluated the toxicity of Abrus precatorius (AP) and Ricinus communis (RC) plants on land snail (Theba pisana) and their effects on biochemical and histological changes in brown rat (Rattus norvegicus). Different concentration (1%, 1.5%, 2% and 2.5%) of AP and RC were used in this study to evluate their effects. The findings of this study pertained that the seeds of AP and RC had potential impact to control T. pisana and the LC50 of AP and RC had negative effects on many life cycle stages of T. pisana. The oviposition and new generation of T. pisana decreased by 81.2% and 62.5% and by 100% and 96.7%, while the infertility rate declined by 96.4% and 82.4% after treating T. pisana by AP and RC, respectively. Results also showed that AP and RC had weak influences on the liver, spleen, intestine, kidney and testis tissues of R. norvegicus. Furthermore, the effect was relatively higher for A. precatorius than R. communis on R. norvegicus males.
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Martini, Thomas, Atiqullah Aziz, Florian Roghmann, Michael Rink, Felix K. Chun, Margit Fisch, Lutz Trojan i in. "Prediction of Locally Advanced Urothelial Carcinoma of the Bladder Using Clinical Parameters before Radical Cystectomy - A Prospective Multicenter Study". Urologia Internationalis 96, nr 1 (1.07.2015): 57–64. http://dx.doi.org/10.1159/000433606.
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Introduction: We aimed at developing and validating a pre-cystectomy nomogram for the prediction of locally advanced urothelial carcinoma of the bladder (UCB) using clinicopathological parameters. Materials and Methods: Multicenter data from 337 patients who underwent radical cystectomy (RC) for UCB were prospectively collected and eligible for final analysis. Univariate and multivariate logistic regression models were applied to identify significant predictors of locally advanced tumor stage (pT3/4 and/or pN+) at RC. Internal validation was performed by bootstrapping. The decision curve analysis (DCA) was done to evaluate the clinical value. Results: The distribution of tumor stages pT3/4, pN+ and pT3/4 and/or pN+ at RC was 44.2, 27.6 and 50.4%, respectively. Age (odds ratio (OR) 0.980; p < 0.001), advanced clinical tumor stage (cT3 vs. cTa, cTis, cT1; OR 3.367; p < 0.001), presence of hydronephrosis (OR 1.844; p = 0.043) and advanced tumor stage T3 and/or N+ at CT imaging (OR 4.378; p < 0.001) were independent predictors for pT3/4 and/or pN+ tumor stage. The predictive accuracy of our nomogram for pT3/4 and/or pN+ at RC was 77.5%. DCA for predicting pT3/4 and/or pN+ at RC showed a clinical net benefit across all probability thresholds. Conclusion: We developed a nomogram for the prediction of locally advanced tumor stage pT3/4 and/or pN+ before RC using established clinicopathological parameters.
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Waqas, Muhammad, Syed Zameer Ul Hassan, Saqib Siddique, Ali Asghar, Anila Ali, Ali Raza Shafqat, Zafar Javed, Zohaib Iqbal i Mehwish Hafeez. "Effective reduction clearing parameters involving alternative reducing agent". Journal of the Pakistan Institute of Chemical Engineers 49, nr 1 (31.05.2021): 51–61. http://dx.doi.org/10.54693/piche.04916.
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Dyeing of polyester is done by using disperse dyes. Some of the disperse dyes remain unfixed during dyeing and create problems in shade and colorfastness properties. Reduction clearing (RC) is a process to remove these unfixed dyes and to enhance colorfastness properties. In the Pakistani textile industry, reduction clearing is being done by using sodium dithionite (Na2S2O4), which has the best results in reducing dyestuff. The problem with sodium dithionite is that it is sensitive to air and also creates a lot of environmental issues. Its sensitivity causes inconsistent results of reduction clearing. Different dyers used different processes and recipes of reduction clearing. Thiourea Dioxide (TUD) is a green reducing agent and can be used as a replacement for sodium dithionite. TUD (CH4N2S) is a stable product with a comparable result with sodium dithionite. Interlock knitted fabric is used in this project whose composition has recycled polyester. The fabric was first dyed using black dyestuff and then reduction clearing was done on a lab-scale with different factors (Shade depth, the concentration of TUD, RC temperature). Three colorfastness tests were conducted to evaluate the different levels of each factor i.e. colorfastness to washing, fastness to perspiration, and fastness to water according to standard numbers ISO 105-C06, ISO 105-E04, and ISO 105-E01, respectively. It was observed that shade depth does not affect the results while concentration and RC temperature have a significant effect on the results. Moreover, the effective concentration of TUD was also determined.
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Cai, Deyu, Yigong Yang, Pei Zhou i Nianqiang Li. "Enhanced Prediction Performance of Reservoir Computing Based on Mutually Delay-Coupled Semiconductor Lasers via Parameter Mismatch". Electronics 11, nr 16 (17.08.2022): 2577. http://dx.doi.org/10.3390/electronics11162577.
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As an efficient information processing method, reservoir computing (RC) is essential to artificial neural networks (ANNs). Via the Santa Fe time series prediction task, we numerically investigated the effect of the mismatch of some critical parameters on the prediction performance of the RC based on two mutually delay-coupled semiconductor lasers (SLs) with optical injection. The results show that better prediction performance can be realized by setting appropriate parameter mismatch scenarios. Especially for the situation with large prediction errors encountered in the RC with identical laser parameters, a suitable parameter mismatch setting can achieve computing performance improvement of an order of magnitude. Our research is instructive for the hardware implementation of laser-based RC, where the parameter mismatch is unavoidable.
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Li, Zele, Mohammad Noori, Chunfeng Wan, Bo Yu, Bochen Wang i Wael A. Altabey. "A Deep Learning-Based Approach for the Identification of a Multi-Parameter BWBN Model". Applied Sciences 12, nr 19 (21.09.2022): 9440. http://dx.doi.org/10.3390/app12199440.
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A restoring-force model is a versatile mathematical model that can describe the relationship between the restoring force and the deformation obtained from a large number of experiments. Over the past few decades, a large body of work on the development of restoring-force models has been reported in the literature. Under high intensity cyclic loadings or seismic excitations, reinforced concrete (RC) structures undergo a wide range of hysteretic deteriorations such as strength, stiffness and pinching degradations. These characteristic behaviors can be described by the multi-parameter Bouc-Wen-Baber-Noori (BWBN) model, which offers a wide range of applicability. This model has been applied for the response prediction and modeling restoring-force behavior in structural and mechanical engineering systems, by adjusting the distribution range of this model’s parameters. However, a major difficulty in utilizing the multi-parameter BWBN model is the parameters’ identification. In this paper, a deep neural network model is used to estimate the hysteresis parameters of the BWBN model. This model is one of the most versatile and widely used general hysteresis models that can describe the hysteretic behavior of RC columns. The experimental data of the RC columns used in this paper are collected from the database of the Pacific Earthquake Engineering Research Center (PEER). Firstly, the hysteretic loop obtained from a physical experiment is described by the BWBN model, and the parameters of the BWBN model are identified via a genetic optimization algorithm. Then a neural network is established by a backpropagation (BP) algorithm for associating the identified BWBN model parameters with physical parameters of the RC column. Finally, the regression analysis of the identified parameters is carried out to obtain the regression characteristics of the RC columns. The trained neural network model can directly identify the parameters of BWBN model based on the physical parameters of RC columns, and is effective and computationally efficient for multi-parameter BWBN model identification. The proposed approach overcomes the difficult problem of identifying the parameters of BWBN model and provides a promising approach for a wider application of this multi-parameter hysteresis model.
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Wang, Shu, i Xiaodian Chen. "3D Parameter Maps of Red Clump Stars in the Milky Way: Absolute Magnitudes and Intrinsic Colors". Astrophysical Journal 923, nr 2 (1.12.2021): 145. http://dx.doi.org/10.3847/1538-4357/ac22a7.
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Abstract Red clump stars (RCs) are useful tracers of distances, extinction, chemical abundances, and Galactic structures and kinematics. Accurate estimation of RC parameters—absolute magnitude and intrinsic color—is the basis for obtaining high-precision RC distances. By combining astrometric data from Gaia; spectroscopic data from APOGEE and LAMOST; and multiband photometric data from Gaia, APASS, Pan-STARRS1, 2MASS, and WISE surveys, we use a Gaussian process regression to train machine learners to derive the multiband absolute magnitudes M λ and intrinsic colors ( λ 1 − λ 2 ) 0 for each spectral RC. The dependence of M λ on metallicity decreases from optical to infrared bands, while the dependence of M λ on age is relatively similar in each band. ( λ 1 − λ 2 ) 0 are more affected by metallicity than age. The RC parameters are not suitable to be represented by simple constants but are related to the Galactic stellar population structure. By analyzing the variation of M λ and ( λ 1 − λ 2 ) 0 in the spatial distribution, we construct (R, z) dependent maps of mean absolute magnitudes and mean intrinsic colors of the Galactic RCs. Through external and internal validation, we find that using three-dimensional (3D) parameter maps to determine RC parameters avoids systematic bias and reduces dispersion by about 20% compared to using constant parameters. Based on Gaia's EDR3 parallax, our 3D parameter maps, and extinction–distance profile selection, we obtain a photometric RC sample containing 11 million stars with distance and extinction measurements.
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Iova, Andrei Radu, Cecilia Violeta Neagu i Daniela Cretu. "Case Study Regarding the Variation of the Qualitative Parameters of Wastewater". Revista de Chimie 72, nr 2 (7.05.2021): 1–8. http://dx.doi.org/10.37358/rc.21.2.8414.
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Romania is making efforts in order to enforce the Directive concerning urban waste water treatment and was left behind by other member states. Starting from the premise that the lack of a proper treatment of wastewater can negatively influence the quality of the emissary in which they are discharged., we proposed that in this paper we analyze the main indicators of wastewater quality, identifying also the causes of water pollution. For this purpose, we followed the variation of five representative indicators of wastewater from Calarasi Wastewater Treatment Plan: chemical oxygen consumption, biochemical oxygen consumption, total nitrogen, total phosphorus, suspended solids. The best results in purification were observed regarding the biochemical oxygen consumption (over 95%). The low temperature of wastewater at the entrance to the Wastewater Treatment Plant during winter leads to a difficult exploitation of the biological step and implicitly to the increase of the phosphorus and total nitrogen concentration in the effluent, which means a weak process of eutrophication in the emissary.
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Nita, Lucian, Dorin Tarau, Gheorghe Rogobete, Simona Nita, Radu Bertici, Ioana Tuta Sas, Ioan Sas i Daniel Dicu. "The Role of Ecopedological Parameters in Management Sustainability of Banat Lands". Revista de Chimie 69, nr 3 (15.04.2018): 688–92. http://dx.doi.org/10.37358/rc.18.3.6176.
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The issue addressed relates to an area of 1891694 ha of which 1183343 ha are agricultural land (62, 56) located in the south-west of Romania and refer to the use of soil chemical and physical properties as an acceptor for certain crop systems, with minimal undesirable effects both for plants to be grown, as well as soil characteristics and groundwater surface quality. It is therefore necessary on a case-by-case basis, measure stoc or rect the acidic reaction by periodic or alkaline calculations, the improvement of plant nutrition conditions through ameliorative fertilization and the application of measures to improve the physical state, sufficient justification for the need to develop short and long term strategies for the protection and conservation of edifying factors and the need to respect the frequency of field and laboratory investigations at all 8x8 km grids of the National Soil-Grounds Monitoring System (organized by I.C.P.A.) and completing it with the relevant pedological and agrochemical studies.
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Rusanescu, Marin, Carmen Otilia Rusanescu i Gigel Paraschiv. "Analysis of Atmospheric Pollutants in Bucharest in Correlation with Meteorological Parameters". Revista de Chimie 69, nr 8 (15.09.2018): 2005–11. http://dx.doi.org/10.37358/rc.18.8.6463.
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In this paper we analyze the correlation between meteorological parameters (wind speed and direction, relative humidity, air temperature) and atmospheric pollutants in Bucharest during the cold period 26.02.2018-02.03.2018, which was based on the monitoring of the concentrations of nitrogen oxides, NO2, O3 and SO2 sulfur dioxide within 24 h and the occurrence of exceedances above the prescribed limit. It was found based on the results obtained that the wind direction influences not only the concentrations of pollutants but also the correlation between the pollutants. Traffic pollutants were at the highest concentration when the wind speed was low. We have found that the highest average concentration for NO2, NOx, NO, O3 occurred at 90% indicative humidity for vertical mixing of strong pollutants. Sulfur dioxide did not record exceeding over the limit standard in the analyzed period.
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Solomon, Sorina Mihaela, Marilena Bataiosu, Dora Maria Popescu, Anne Marie Rauten, Dorin Nicolae Gheorghe, Roxana Adina Petrescu, George Alexandru Maftei i Camelia Fiera Maglaviceanu. "Biochemical Assesment of Salivary Parameters in Young Patients with Dental Lesions". Revista de Chimie 70, nr 11 (15.12.2019): 4095–97. http://dx.doi.org/10.37358/rc.19.11.7709.
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Dental injuries, especially those in the frontal area, through the complications they can cause, are an important topic due to the psychosocial impact they have on young patients. Saliva is an important biological resource, useful for conducting diagnostic tests; also, it can be harvested non-invasively, without the need for prior training or special equipment. The biochemical analysis of the concentration of salivary parameters may suggest the susceptibility and resistance to carious lesions. The aim of the present study is to evaluate a causal relationship between the values of salivary parameters, salivary calcium, phosphates and salivary pH, and the incidence of dental caries.
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Matei, Gabi Mirela, Sorin Matei, Maria Pele, Flavia Dumitrescu i Adrian Matei. "Invertase Production by Fungi, Characterization of Enzyme Activity and Kinetic Parameters". Revista de Chimie 68, nr 10 (15.11.2017): 2205–8. http://dx.doi.org/10.37358/rc.17.10.5856.
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The present paper presents the results of research carried out on 14 fungal isolates of various origins aiming to select new efficient sources for invertase production for further biotechnological application. Aspergillus flavus presented the highest protein content and Aspergillus niger, the most intense invertase activity. The relationship between enzyme concentration and enzymatic activity at 0.25 mM mL-1sucrose as substrate assayed for successive decimal dilutions of Aspergillus niger enzyme ranging from 0.1 to 1mlLrevealed a linear correspondence between 0.1 and 0.5mL. The kinetic parameters Michaelis-Menten constant (Km) and maximal velocity (Vmax) for invertase activity of Aspergillus niger, Penicillium aurantiogriseum, Aspergillus wentii and Rhizopus stolonifer were calculated. The determination coefficients R2 calculated from Lineweaver-Burk plots presented values very close or equal to 1.
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Baran*, Halina, Katrin Staniek, Melanie Bertignol-Spörr, Martin Attam, Carina Kronsteiner i Berthold Kepplinger. "Effects of Various Kynurenine Metabolites on Respiratory Parameters of Rat Brain, Liver and Heart Mitochondria". International Journal of Tryptophan Research 9 (styczeń 2016): IJTR.S37973. http://dx.doi.org/10.4137/ijtr.s37973.
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Previously, we demonstrated that the endogenous glutamate receptor antagonist kynurenic acid dose-dependently and significantly affected rat heart mitochondria. Now we have investigated the effects of L-tryptophan, L-kynurenine, 3-hydroxykynurenine and kynurenic, anthranilic, 3-hydroxyanthranilic, xanthurenic and quinolinic acids on respiratory parameters (ie, state 2, state 3), respiratory control index (RC) and ADP/oxygen ratio in brain, liver and heart mitochondria of adult rats. Mitochondria were incubated with glutamate/malate (5 mM) or succinate (10 mM) and in the presence of L-tryptophan metabolites (1 mM) or in the absence, as control. Kynurenic and anthranilic acids significantly reduced RC values of heart mitochondria in the presence of glutamate/malate. Xanthurenic acid significantly reduced RC values of brain mitochondria in the presence of glutamate/malate. Furthermore, 3-hydroxykynurenine and 3-hydroxyanthranilic acid decreased RC values of brain, liver and heart mitochondria using glutamate/malate. In the presence of succinate, 3-hydroxykynurenine and 3-hydroxyanthranilic acid affected RC values of brain mitochondria, whereas in liver and heart mitochondria only 3-hydroxykynurenine lowered RC values significantly. Furthermore, lowered ADP/oxygen ratios were observed in brain mitochondria in the presence of succinate with 3-hydroxykynurenine and 3-hydroxyanthranilic acid, and to a lesser extent with glutamate/malate. In addition, 3-hydroxyanthranilic acid significantly lowered the ADP/oxygen ratio in heart mitochondria exposed to glutamate/malate, while in the liver mitochondria only a mild reduction was found. Tests of the influence of L-tryptophan and its metabolites on complex I in liver mitochondria showed that only 3-hydroxykynurenine, 3-hydroxyanthranilic acid and L-kynurenine led to a significant acceleration of NADH-driven complex I activities. The data indicate that L-tryptophan metabolites had different effects on brain, liver and heart mitochondria. Alterations of L-tryptophan metabolism might have an impact on the bioenergetic activities of brain, liver and/or heart mitochondria and might be involved in the development of clinical symptoms such as cardiomyopathy, hepatopathy and dementia.
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Kopczynska, Maja, Stephanie Smits, Rebecca Hopps, Rajeswari Ramaraj, Neil Warren, Stuart Goddard, Xujiong Ye i Sunil Dolwani. "Assessment of technical parameters and skills training to inform a simulation-based training program for semi-automated robotic colonoscopy". Endoscopy International Open 07, nr 01 (styczeń 2019): E9—E14. http://dx.doi.org/10.1055/a-0774-4554.
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Abstract Background and study aims Video-colonoscopy, despite being the gold-standard for diagnosis of colorectal lesions, has limitations including patient discomfort and risk of complications. This study assessed training characteristics and acceptability in operators of a new robotic colonoscope (RC). Materials and methods Participants (n = 9) with varying degrees of skill and background knowledge in colonoscopy performed colonoscopies with a RC on a simulation-based training model. Quantitative procedure-related and qualitative operator-related parameters were recorded. Results Polyp detection rate was highest in the novice group (91.67 %) followed by experts (86.11 %), then equally, trainees and video gamers (79.17 %). Four participants repeated the procedure at a follow-up session. Each participant improved cecal intubation time and had the same or higher polyp detection rate. The potential role for RC was identified for an out-of-hospital environment and as a novel diagnostic tool. Conclusions Results from this pilot suggest that operators at all skill levels found the RC acceptable and potentially useful as a diagnostic tool. Acquisition of skills with RC seems to improve rapidly to a clinically relevant level with simulation-based training
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Zhang, Wenjiao, Xiangqing Kong, Yandong Qu i Qian Zhao. "Numerical Simulation of Cracked Reinforced Concrete Slabs Subjected to Blast Loading". Civil Engineering Journal 4, nr 2 (6.03.2018): 320. http://dx.doi.org/10.28991/cej-030994.
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Crack is one of the most common defects observed in reinforced concrete (RC) structures. An initial crack will lead to severe changes in the stress state when the structure subjected to blast loadings. Target on acquiring the dynamic data, a finite element method is applied to simulate the response of cracked RC slab subjected to blast loading. The theoretical results of damage distribution and mid-span deflection of normal specimens are first compared with experimental test, which indicates that the dynamic behaviour of RC slab under blast loading can be well predicted by the finite element model. Then blast responses of cracked RC slabs with varied crack parameters (e.g. orientation, width and depth) are systematically studied. Results show that damage of the cracked slab initiates from the initial crack tip of the bottom surface, and then it propagates quickly with cracks found in the support areas on the top surface. In addition, the existence of initial cracks in the RC slab make it subject to more serious damages than the normal RC slab under the same explosive loads, as well as a short reacted failure time. Moreover, variations of crack parameters have slight influences on the distributions of cracked RC slab.
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Abbasi, Amirali, Omar Chaallal i Georges El-Saikaly. "Shear Strengthening of RC Beams with FRP Composites: Database of FE Simulations and Analysis of Studied Parameters". Modelling and Simulation in Engineering 2022 (21.01.2022): 1–27. http://dx.doi.org/10.1155/2022/7725025.
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The use of externally bonded fiber-reinforced polymer (EB-FRP) composites for shear strengthening of reinforced concrete (RC) beams presents many challenges given the complex phenomena that come into play. Premature bond failure, the behavior of the interface layer between FRP composites and the concrete substrate, the complex and brittle nature of shear cracks, and the adverse interaction between internal steel stirrups and EB-FRP are some of these phenomena. Compared to experimental investigations, the finite element (FE) technique provides an accurate, cost-effective, and less time-consuming tool, enabling practicing engineers to perform efficient, accurate nonlinear and dynamic analysis as well as parametric studies on RC beams strengthened with EB-FRP. Since 1996, many numerical studies have been carried out on the response of RC beams strengthened using FRP. However, only a few have been related to RC beams strengthened in shear using EB-FRP composites. In addition, the analytical models that have been reported so far have failed to address and encompass all the factors affecting the contribution of EB-FRP to shear resistance because they have mostly been based on experimental studies with limited scopes. The aim of this paper is to build an extensive database of all the studies using finite element analysis (FEA) carried out on RC beams strengthened in shear with EB-FRP composites and to evaluate their strengths and weaknesses through various studied parameters.
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Manea, Elena, Costel Bumbac, Alina Banciu, Catalina Stoica i Mihai Nita-Lazar. "Kinetical Parameters Evaluation for Microalgae-Bacteria Granules used for Waste Water Treatment". Revista de Chimie 71, nr 1 (7.02.2020): 88–91. http://dx.doi.org/10.37358/rc.20.1.7817.
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A preliminary stage in developing numerical simulations of a biological process for wastewater treatment consists in evaluating the kinetic parameters of the studied process. The study shows results obtained by experimental and numerical evaluation of mixed microalgae-bacteria granules kinetical parameters. The results showed that operational parameters modulated the main kinetic parameters of biological processes involved in removal of organic load and nutrients from wastewater such as biomass production coefficient, endogenous decomposition rate, specific peak rate of growth, semisaturation constant, specific rate of nitrification and the specific denitrification speed. These key parameters were determined over time to evaluate the performance of microbial populations in microalgae-bacteria granules in different operational conditions. Tests have been carried out for various wastewater compositions to determine the versatility and adaptability of the technology.
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Kurniawan, Edi. "On Comparison Between Repetitive Controller and PI Controller Tracking Performance". Jurnal INKOM 8, nr 2 (30.04.2015): 95. http://dx.doi.org/10.14203/j.inkom.417.
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Tracking periodic signals are common task in many control problems. One of the examples is movement control of pick and place robot in industry. The requirement of high tracking accuracy becomes very important in many applications. Therefore, a sophisticated control algorithm that manages to achieve high accuracy tracking of periodic command is required. Repetitive Control (RC) based on internal model principle is one of control schemes that can be employed to achieve perfect tracking of periodic signal. On the other hand, Proportional Integral (PI) controller can also be used for tracking. This paper compares the tracking performance of PI controller, RC, and PI with RC, where PI with RC here is integration between PI controller and RC. Step by step design to obtain the parameters of PI, RC and PI with RC are given. A simulation on servo motor system is carried out to assess the performance of RC, PI, andPI with RC respectively. From the simulation results, the transient response and tracking accuracy are thoroughly discussed.
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Wang, Yukui, Dan Zhang, Jing Liu, Zhangqi Hu i Dou Zhong. "The Seismic Design Process of RC Column Components in SDOF System considering the Earthquake Duration Effect". Shock and Vibration 2023 (7.08.2023): 1–11. http://dx.doi.org/10.1155/2023/5827471.
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In order to study seismic design process of RC (reinforced concrete) column components considering the effect of earthquake duration, the degradation law of capacity under random amplitude hysteresis history was conducted by the research group, and the estimation method for the energy dissipation capacity of RC column components was suggested. Furthermore, the correlation between the stiffness decay index and energy dissipation capacity, hysteresis histories, and structural parameters was proposed, and the performance classification criteria based on the stiffness decay index was established. On this basis, the connection between the stiffness decay index and structural parameters and seismic parameters was established, and the seismic design process of RC column components in SDOF (single degree of freedom) system was proposed. The research indicated that the proposed seismic design process based on stiffness decay index can effectively consider the effect of earthquake duration. The stiffness decay index is more suitable for defining structural damage than deformation index and Park-Ang index. The stiffness decay index establishes quantitative relationships with seismic parameters and structural parameters, facilitating performance-based design in engineering practice. The increase in earthquake duration exacerbates the damage of RC column components, and this effect is more pronounced at the beginning of the earthquake and gradually decreases over time.
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Mahroug, M., H. Azzouzi i I. Linda. "AB0299 ASSOCIATION OF RHEUMATOID CACHEXIA WITH DISEASE PARAMETERS IN MOROCCAN RHEUMATOID ARTHRITIS PATIENTS". Annals of the Rheumatic Diseases 81, Suppl 1 (23.05.2022): 1275.2–1275. http://dx.doi.org/10.1136/annrheumdis-2022-eular.3506.
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BackgroundLow muscle mass occurs in patients with rheumatoid arthritis without weight loss. This condition has been studied lately (1) and was referred to as rheumatoid cachexia (RC).ObjectivesTo study the prevalence of rheumatoid cachexia and its associated factors in rheumatoid arthritis (RA) patients.MethodsWe designed a cross-sectional study on RA patients recruited from December 2021 at our rheumatology department. Exclusion criteria were patients with prior chronic kidney disease, severe heart failure, severe chronic obstructive pulmonary disease, acute liver failure, uncontrolled diabetes, thyroid dysfunction, dysphagia, illicit drug use, and alcohol abuse. Body composition was measured with dual-energy X-ray absorptiometry (DXA), and patients’ data were collected. RC was defined by Engvall et al. (2) as a fat-free mass index (FFMI) below the 10th percentile (under lean) and a fat mass index (FMI) above the 25th percentile (fat excess). Inflammatory activity was measured by C-reactive protein (CRP) and used to assess disease activity score for 28 joints (DAS28CRP). The physical disability was assessed by the Health Assessment Questionnaire (HAQ) and the physical activity by the International Physical Activity Questionnaire (IPAQ). Nutrition was evaluated by the Mini Nutritional Assessment (MNA).ResultsWe included 91 RA patients with a mean age of 52.61 ± 12.99 years. The prevalence of rheumatoid cachexia was 12.1 %. Twenty-six patients (28.6 %) were under lean, and six patients (6.6 %) had excess fat. DAS28CRP (p = 0.004) and fasting glucose (p = 0.03) were significantly lower in RC patients. RC did not show any significant association with HAQ, MNA, physical activity, gender, menopause, seropositivity, lipid levels or BMI. RC was significantly associated with DAS28CRP (p = 0.01, OR = 0.305, 95%IC [0.114, 0.818]) and fasting glucose level (p = 0.02, OR = 0.0002, 95%IC [0.00000001, 0.311]) when adjusting on IPAQ categories and ACPA seropositivity.ConclusionRheumatoid cachexia was frequent in our RA patients. This condition was significantly associated with low fasting blood sugar levels and disease activity.References[1]Santo RC, Silva JM, Lora PS, Moro ALD, Freitas EC, Bartikoski BJ, et al. Cachexia in patients with rheumatoid arthritis: a cohort study. Clin Rheumatol. dec 2020;39(12):3603‑13.[2]Engvall I-L, Elkan A-C, Tengstrand B, Cederholm T, Brismar K, Hafstrom I. Cachexia in rheumatoid arthritis is associated with inflammatory activity, physical disability, and low bioavailable insulin-like growth factor. Scand J Rheumatol. oct 2008;37(5):321‑8.Disclosure of InterestsNone declared
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Zhang, Y. Z., S. G. Wang, S. Jiang, J. H. Wang, X. Z. Wu i T. F. Zhang. "Investigation of performance parameters of building thermal battery". E3S Web of Conferences 356 (2022): 01025. http://dx.doi.org/10.1051/e3sconf/202235601025.
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The concept of a building thermal battery refers to storing the supplied heat and releasing it the another time through radiation and convection. The introduction of building thermal battery performance has created a more convenient solution to the problems of building load estimation, control and optimization, building-grid integration, etc. Some literatures have expanded the original definition of building thermal batteries, including PV RE (photovoltaic renewable energy), HVAC and other units. Starting from the building body, this investigation studies a building energy system. With reference to the performance parameters of traditional rechargeable batteries, the corresponding performance parameters of building thermal batteries are developed. The RC model is further used to model the performance parameters of the building thermal battery respectively. Among them, the corresponding parameter values of the RC model are obtained by parameter identification. Finally, the heat storage and heat release characteristics of the building integrated energy system are obtained. It makes the application of buildings as batteries more flexible in the urban energy network.
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Gheorghe, Catalina Gabriela, Andreea Bondarev i Ion Onutu. "Assessement of Water Quality Parameters in Some Potential Pollutant Areas from Romania". Revista de Chimie 69, nr 8 (15.09.2018): 2045–49. http://dx.doi.org/10.37358/rc.18.8.6470.
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Monitoring of environmental factors allows the achievement of some important objectives regarding water quality, forecasting, warning and intervention. The aim of this paper is to investigate water quality parameters in some potential pollutant sources from northern, southern and east-southern areas of Romania. Surface water quality data for some selected chemical parameters were collected and analyzed at different points from March to May 2017.