Synthesis and crystal structure of a new pyridinium bromide salt: 4-methyl-1-(3-phenoxypropyl)pyridinium bromide

In the cation of the title mol­ecular salt, C15H18NO+·Br−, the pyridinium and phenyl rings are inclined to one another by 11.80 (8)°. In the crystal, the Br− anion is linked to the cation by a C—H...Br hydrogen bond. The cations stack along the b-axis direction and are linked by further C—H...Br inter­actions, and offset π–π interactions [inter­centroid distances = 3.5733 (19) and 3.8457 (19) Å], forming slabs parallel to the ab plane. The effects of the C—H...X− inter­action on the NMR signals of the ortho- and meta-pyridinium protons in a series of related ionic liquids, viz. 4-methyl-1-(4-phen­oxy­but­yl)pyridin-1-ium salts, are reported and discussed

Conventional versus ultrasound and microwave assisted synthesis: Some new environmentally friendly functionalized picolinium-based ionic liquids with potential antibacterial activity

A green chemistry approach has been adopted for the synthesis of thirty-four new picolinium-based ionic liquids by using microwave (MW) and ultrasound (US) irradiation as well as conventional thermal heating. Their structures were confirmed by FT-IR, 1H NMR, 13C NMR, 11B NMR, 19F NMR, 31P NMR, mass spectra and elemental analyses. The antimicrobial profile of these novel ionic liquids was evaluated and the minimum inhibitory concentration (MIC) showed their moderate to low antimicrobial activity against eight types of human pathogens

An Efficient Algorithm for Multimodal Medical Image Fusion based On Feature Selection and PCA Using DTCWT.

Background:   In the two past decades, medical image fusion has become an essential part of modern medicine due to the availability of numerous imaging modalities (MRI, CT, SPECT. etc). This paper presents a new medical image fusion algorithm based on DTCWT and uses different fusion rules in order to obtain a new image which contains more information than any of the input images. Methods: In order to improve the visual quality of the fused image, we propose a new image fusion algorithm based on Dual Tree Complex Wavelet Transform (DTCWT). Using different fusion rules in a single algorithm leads to a perfect reconstruction of the output (fused image).This combination will create a new method which exploits the advantages of each method separately. DTCWT present good directionality since it considers the edge information in six directions and provides approximate shift invariant. The goal of Principal Component Analysis (PCA) is to extract the most significant features (wavelet coefficients in our case) in order to improve the spatial resolution. The proposed algorithm fuses the detailed wavelet coefficients of input images using features selection rule. Results: We have conducted several experiments over different sets of multimodal medical images such as CT/MRI, MRA/T1-MRI; however, only results of two sets have been presented (due to pages-limit). The proposed fusion algorithm is compared to recent fusion methods presented in the literature (eight methods) in terms of visual quality and quantitatively using well known fusion performance metrics (five metrics). Results showed that the proposed algorithm outperforms the existing ones in terms of visual and quantitative evaluations. Conclusion: This paper focuses on image fusion of medical images obtained from different modalities. We have proposed a novel algorithm based on DTCWT in order to merge multimodal medical images. Experiments have been performed over two different sets of multimodal medical images. The results show that the proposed method significantly outperforms other techniques reported in the literature

Analytical models to determine in-plane damage initiation and force capacity of masonry walls with openings

Masonry panels consisting of piers and spandrels in buildings are vulnerable to in-plane actions caused by seismicity and soil subsidence. Tectonic seismicity is a safety hazard for masonry structures, whereas low-magnitude induced seismicity can be detrimental to their durability due to the accumulation of light damage. This is particularly true in the case of unreinforced masonry. Therefore, the development of models for the accurate prediction of both damage initiation and force capacity for masonry elements and structures is necessary. In this study, a method was developed based on analytical modeling for the prediction of the damage initiation mode and capacity of stand-alone masonry piers; the model was then expanded through a modular approach to masonry walls with asymmetric openings. The models account for all potential damage and failure modes for in-plane loaded walls. The stand-alone piers model is applicable to all types of masonry construction. The model for walls with openings can be applied as is to simple buildings but can also be extended to more complex structures with simple modifications. Model results were compared with numerous experimental cases and exhibited very good accuracy.Peer ReviewedPostprint (author's final draft

Experimental characterization of the axial behavior of traditional masonry wall metal tie connections in cavity walls

In recent years, the number of human-induced earthquakes in Groningen, a large gas field in the north of the Netherlands, has increased. The majority of the buildings are built by using unreinforced masonry (URM), most of which consists of cavity (i.e. two-leaf) walls, and were not designed to withstand earthquakes. Efforts to define, test and standardize the metal ties, which do play an important role, are valuable also from the wider construction industry point of view. The presented study exhibits findings on the behavior of the metal tie connections between the masonry leaves often used in Dutch construction practice, but also elsewhere around the world. An experimental campaign has been carried out at Delft University of Technology to provide a complete characterization of the axial behavior of traditional connections in cavity walls. A large number of variations was considered in this research: two embedment lengths, four pre-compression levels, two different tie geometries, and five different testing protocols, including monotonic and cyclic loading. The experimental results showed that the capacity of the connection was strongly influenced by the embedment length and the geometry of the tie, whereas the applied pre-compression and the loading rate did not have a significant influence

Numerical modelling of cavity wall metal ties

The assessment of the out-of-plane response of unreinforced masonry (URM) buildings with cavity walls has been a popular topic in regions such as Central and Northern Europe, Australia, New Zealand, China and several other countries. Cavity walls are particularly vulnerable as the out-of-plane capacity of each individual leaf is significantly smaller than the one of a solid wall. In the Netherlands, cavity walls are characterized by an inner load-bearing leaf of calcium silicate bricks, and by an outer veneer of clay bricks that has only aesthetic and insulation functions. The two leaves are typically connected by means of metallic ties. This paper utilizes the results of an experimental campaign conducted by the authors to calibrate a hysteretic model that represents the axial cyclic response of cavity wall tie connections. The proposed numerical model uses zero-length elements implemented in OpenSees with the Pinching4 constitutive model to account for the compression-tension cyclic behaviour of the ties. The numerical model is able to capture important aspects of the tie response such as the strength degradation, the unloading stiffness degradation and the pinching behaviour. The numerical modelling approach in this paper can be easily adopted by practitioner engineers who aim to model the wall ties more accurately when assessing the structures against earthquakes

An Efficient Algorithm for Multimodal Medical Image Fusion based on Feature Selection and PCA Using DTCWT (FSPCA-DTCWT)

Background: During the two past decades, medical image fusion has become an essential part ofmodern medicine due to the availability of numerous imaging modalities (e.g., MRI, CT, SPECT,etc.). This paper presents a new medical image fusion algorithm based on PCA and DTCWT,which uses different fusion rules to obtain a new image containing more information than any ofthe input images.Methods: A new image fusion algorithm improves the visual quality of the fused image, based onfeature selection and Principal Component Analysis (PCA) in the Dual-Tree Complex WaveletTransform (DTCWT) domain. It is called Feature Selection with Principal Component Analysisand Dual-Tree Complex Wavelet Transform (FSPCA-DTCWT). Using different fusion rules in asingle algorithm result in correctly reconstructed image (fused image), this combination willproduce a new technique, which employs the advantages of each method separately. The DTCWTpresents good directionality since it considers the edge information in six directions and providesapproximate shift invariant. The main goal of PCA is to extract the most significant characteristics(represented by the wavelet coefficients) in order to improve the spatial resolution. The proposedalgorithm fuses the detailed wavelet coefficients of input images using features selection rule.Results: Several experiments have been conducted over different sets of multimodal medicalimages such as CT/MRI, MRA/T1-MRI. However, due to pages-limit on a paper, only results ofthree sets have been presented. The FSPCA-DTCWT algorithm is compared to recent fusionmethods presented in the literature (eight methods) in terms of visual quality and quantitativelyusing well-known fusion performance metrics (five metrics). Results showed that the proposedalgorithm outperforms the existing ones regarding visual and quantitative evaluations.Conclusion: This paper focuses on medical image fusion of different modalities. A novel imagefusion algorithm based on DTCWT to merge multimodal medical images has been proposed.Experiments have been performed using two different sets of multimodal medical images. Theresults show that the proposed fusion method significantly outperforms the recent fusiontechniques reported in the literature