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The article presents the results of numerical analyses and experimental research concerning the neural evaluation of the mass moisture content U_(mc) of brick walls in historic buildings. For the purpose of training, testing and v...
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The article presents the results of numerical analyses and experimental research concerning the neural evaluation of the mass moisture content U_(mc) of brick walls in historic buildings. For the purpose of training, testing and validating artificial neural networks, a representative data set was built on the basis of tests of the moisture content and salinity of brick walls in ten historic buildings. The article presents two structures of artificial neural networks that are most useful for the neural evaluation of the mass moisture content, which were selected on the basis of the conducted analyzes. The results of comparative applications of all analysed algorithms were also included in the paper. High R~2 values for learning, testing and validation using artificial neural networks prove the credibility of the results. This means that the proposed method can be used in construction practice to assess, after practical verification, the moisture content of brick walls.
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The article proposes a method of neural identification of the moisture content in saline brick walls in historic buildings, which is based on non-destructive testing. The method involves the use of artificial neural networks (ANNs...
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The article proposes a method of neural identification of the moisture content in saline brick walls in historic buildings, which is based on non-destructive testing. The method involves the use of artificial neural networks (ANNs), which are trained, tested and experimentally verified on a set of data constructed for this purpose. The set consists of the results of tests that were obtained using non-destructive methods on a selected representative group of masonry historic buildings. Based on numerical analyses, an appropriate type and structure of ANN, as well as a learning algorithm, were selected. Positive results were obtained, indicating the possibility of using the proposed method in practice. According to the authors, a wider use of the proposed method requires verification on other historic buildings. In order for other researchers to be able to verify the presented approach, a full set of data used for training and testing the ANN was provided.
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Estimating the load-bearing capacity of brick masonry walls is a fundamental aspect of the design or retrofitting of this type of structures. This paper presents a new ANN-based proposal as an alternative to the different existing...
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Estimating the load-bearing capacity of brick masonry walls is a fundamental aspect of the design or retrofitting of this type of structures. This paper presents a new ANN-based proposal as an alternative to the different existing methods. The proposal takes into account load eccentricity, wall slenderness ratio and stiffness and masonry tensile strength, and is validated by a comparison with the Eurocode 6 and other formulations as well as three other experimental studies. The proposal closely agrees with the experimental results and is less conservative than Eurocode 6 and therefore more likely to provide the optimum design for masonry walls.
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The cyclic silver (I) dimer [Ag(m-bitmb)]_2 (PF_6)_2 centre dot 2MeCN of 1,3-bis(imidazolylmethyl)-2,4,6-trimethylbenzene (m-bitmb) was prepared and its structure characterized by X-ray crystallography. An PF_6~- anion is encapsul...
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The cyclic silver (I) dimer [Ag(m-bitmb)]_2 (PF_6)_2 centre dot 2MeCN of 1,3-bis(imidazolylmethyl)-2,4,6-trimethylbenzene (m-bitmb) was prepared and its structure characterized by X-ray crystallography. An PF_6~- anion is encapsulated within the macrocyclic cation [Ag(m-bitmb)]_2~(2+) with weak Ag… F and CH…F interactions. Two types of intermolecular #pi#-#pi# interactions lead to a brick wall network.
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Crystallization of 1,3,5-tris(4-cyanobenzoyl)benzene (1) from EtOAc, MeNO2, and 3-pentanone results in formation of isostructural inclusion complexes mediated by weak hydrogen bonding interactions involving aryl C-H donors and het...
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Crystallization of 1,3,5-tris(4-cyanobenzoyl)benzene (1) from EtOAc, MeNO2, and 3-pentanone results in formation of isostructural inclusion complexes mediated by weak hydrogen bonding interactions involving aryl C-H donors and heteroatom acceptors from nitrile, carbonyl, and nitro groups. The solvent guests occupy interlayer channels within a porous triaroylbenzene host network.
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The article presents the results of experimental research and numerical analyses, and also shows the usefulness of the random forest algorithm and the support vector machine for the non-destructive identification of the moisture c...
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The article presents the results of experimental research and numerical analyses, and also shows the usefulness of the random forest algorithm and the support vector machine for the non-destructive identification of the moisture content of brick walls in historic buildings. To train and test the models, a representative dataset, including 290 sample sets and 7 predictor variables, was used. These variables are: Y - describing the year of construction of the building; X_D, X_M, U_m - describing the wall's moisture; X_C, X_S, X_A - describing the concentration of salts in the wall. The analyses showed that the random forest algorithm is the most predisposed model for the non-destructive assessment of the U_(mc) mass moisture content of brick walls in historic buildings. This is proved by the highest value of the R~2, amounting to 0.968, and the lowest values of RMSE, MAE and MAPE, amounting to 1.080%, 0.791 and 14.28%, respectively.
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The reactions of Cu(II) with the mixed nitrilotriacetic acid (H(3)NTA) and 4,4'-bipyridyl (4,4'-bpy) ligands in different metal-to-ligand ratios in the presence of NaOH and NaClO4 afforded two complexes, Na-3[Cu-2(NTA)(2)(4,4'-bpy...
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The reactions of Cu(II) with the mixed nitrilotriacetic acid (H(3)NTA) and 4,4'-bipyridyl (4,4'-bpy) ligands in different metal-to-ligand ratios in the presence of NaOH and NaClO4 afforded two complexes, Na-3[Cu-2(NTA)(2)(4,4'-bpy)]-ClO(4)center dot 5H(2)O (1) and [Cu-2(NTA) (4,4'-bpy)(2)]ClO(4)center dot 4H(2)O (2). The two complexes have been characterized by elemental analysis, IR, XRD, and single-crystal X-ray diffraction. 1 contains a basic doubly negatively charged [Cu-2(NTA)(2)-(4,4'-bpy)](2-) dinuclear unit which was further assembled via multiple Na-O and O-(HO)-O-... interactions into a three-dimensional (3D) pillared-layer structure. 2 features a two-dimensional (2D) undulated brick-wall architecture containing a basic doubly positively charged [Cu-4(NTA)(2)(4,4'-bpy)(2)](2+) tetranuclear unit. The 2D network possesses large cavities hosting guest molecules and was further assembled via O-(HO)-O-... hydrogen bonds into a 3D structure with several channels running in different directions.
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The modal transmission-line (MTL) method is used to analyze the shielding effectiveness of buildings, which is an important parameter for the accurate planning of microcellular communication networks. For that, the buildings are m...
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The modal transmission-line (MTL) method is used to analyze the shielding effectiveness of buildings, which is an important parameter for the accurate planning of microcellular communication networks. For that, the buildings are modeled as multilayer lossy periodic structures. After a description of the extended MTL-theory, the newly developed MTL model is applied to brick walls, reinforced-concrete walls and concrete block walls. From a comparison of the MTL-results with previously published theoretical or experimental results it is concluded that the MTL method is very well suited, because it is accurate as well as computational time-efficient.
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Novel cadmium coordination polymers [CdL1.5(NO3)(2)] (1), [CdL2(NO3)2]center dot(C6H6) (2), and [CdL2(NO3)(2)]center dot 2(C4H8O) (3), which contain a common long 3,3'-bipyridyl-type ligand, were prepared from Cd(NO3)(2)center dot...
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Novel cadmium coordination polymers [CdL1.5(NO3)(2)] (1), [CdL2(NO3)2]center dot(C6H6) (2), and [CdL2(NO3)(2)]center dot 2(C4H8O) (3), which contain a common long 3,3'-bipyridyl-type ligand, were prepared from Cd(NO3)(2)center dot 4H(2)O and ligand L (3-py-CH=N-(CH3)C6H3-C6H3(CH3)-N=CH-3-py). Whereas polymer 1 was prepared by solvothermal reactions, polymers 2 and 3 were prepared by layer diffusion. All have a repeating 84-membered ring unit. Polymer 1 has a non-interpenetrated 1-D ladder structure, and polymers 2 and 3 have a 2-D brick-wall structure. In particular, polymers 2 and 3 contain guest molecules (benzene (2) or THF (3)) in their frameworks, and the desorption-resorption behavior of the guest molecules is rather reversible. (C) 2007 Published by Elsevier B.V.
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Time-domain free-field measurements comprised the dielectric properties of several common building materials using dual-ridged guide antennas and 1 mtimes1 m samples placed on an optical table covered with an absorber. The samples...
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Time-domain free-field measurements comprised the dielectric properties of several common building materials using dual-ridged guide antennas and 1 mtimes1 m samples placed on an optical table covered with an absorber. The samples are polycarbonate, gypsum, plywood, a brick wall, and a concrete wall. Time gating and deconvolution are used to isolate a sample's front and back surfaces to obtain the measured reflection coefficients (RCs) and transmission coefficients. Theoretical reflection and transmission equations were generated from a plane-wave model. Relative permittivity is obtained by varying the parameters in the Kirkwood-Fuoss equation until a best fit between the theoretical and measured reflection and transmission coefficients is obtained.
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