Copper(II)-oxaloyldihydrazone complexes: Physico-chemical studies: Energy band gap and inhibition evaluation of free oxaloyldihydrazones toward the corrosion of copper metal in acidic medium

AbstractA series of oxaloyldihydrazone ligands were prepared essentially by the conventional condensation reaction between oxaloyldihydrazide and different aldehydes e.g., salicylaldehyde, 2-hydroxy-1-naphthaldehyde, 2-hydroxyacetophenone and 2-methoxybenzaldehyde in 1:2M ratio. The synthesized compounds were purified to give bis(salicylaldehyde)oxaloyldihydrazone (L1), bis(2-hydroxy-1-naphthaldehyde)oxaloyldihydrazone (L2), bis(2-hydroxyacetophenone)oxaloyldihydrazone (L3) and bis(2-methoxybenzaldehyde)oxaloyldihydrazone (L4). All the oxaloyldihydrazones (L1–L4) and their relevant solid copper(II) complexes have been isolated and characterized by various physicochemical techniques. The identity of the synthesized compounds has been ascertained on the basis of elemental analyses, spectral (UV–Vis, IR, ESR, mass, 1H NMR), magnetism and thermal (TG) measurements. The dihydrazones coordinate to the metal center forming binuclear complexes. Upon chelation, the metal center can form a trigonal distorted octahedral structure with L1 and pseudo tetrahedral configuration with L2 & L3 & L4. The optical band gap energy for all compounds underlies the range of semiconductor materials. The investigated ligands were assayed for their corrosion inhibitive and adsorptive properties on copper surface in 1M HCl solution using weight loss technique. The results pointed out that, the ligands have a plausible inhibition toward the corrosion of copper specimen. The adsorption reaction on copper surface was found to be spontaneous first order and agreed with physical adsorption mechanism. The adsorption data fitted well to Freundlich, Langmuir and Frumkin adsorption isotherms

Damage detection of flexural structural systems using damage index method – Experimental

In the framework of structural health monitoring, continuous dynamic records are essential for good judgment of structures. Overall degradation of structures can be obtained with reasonable accuracy using various system identification techniques. It is however, challenging to obtain precisely the position and size of local damages. The current research focuses on Damage Index Method (DIM) as a tool for determining local damages occurred in flexural structural elements. The DIM technique depends on comparing modal strain energies of structures at different degradation stages. Self-made computer module was developed to encounter DIM for damage detection. First, the method was verified experimentally. Simply supported steel beam of 1500 mm (length), 50 mm (width) and 6 mm (thickness), in addition to steel plate of area 930 × 910 mm and 3 mm (thickness) was implemented in the experimental program. Both the beam and plate were subjected to different damage configurations. Collected acceleration time history was processed and used to verify the adequacy of DIM in identifying damages in the used physical models. Numerical parametric study was also conducted on a variety of beams and plates with various damage degrees and locations. It was noticed that both the experimental and numerical results showed good agreement in identifying damages in flexural structural elements

Damage detection of plate-like structures based on residual force vector

AbstractStructural health monitoring is essential to maintain the structural integrity by predicting problems in an early time. This consequently could be reflected on extending the life time of structures. Nondestructive tests based on dynamic measures are usually fast and economic in detecting damages of structures. Various numerical techniques together with recording time histories are used for this purpose. This paper presents a numerical method for damage detection in plate-like structures. The modeling of damage was conducted commercially using the module of MatLab. Comparison of different mode shapes was used in the analysis to detect the location of local damage based on residual force vector. The technique utilized the node residual force vector to locate and evaluate the degree of the suspected damaged elements. In the current study, three configurations for plates were used. The study also concentrated on the efficiency of the new method in identifying damages of different degradation levels. The plates were subjected to different combinations of artificial damages applied at various positions on each plate. The study was not only able to identify the location but also the degree of damage in plates. It has been noted that identification of severe degradation was more precisely identified. As a result, the residual force method is the simplest damage quantification technique which approved to be accurate enough to be used in practical applications

Physicochemical studies on some selected oxaloyldihydrazones and their novel palladium(II) complexes along with using oxaloyldihydrazones as corrosion resistants

<p>New palladium (II) oxaloyldihydrazone complexes are reported and characterized. The mode of bonding as well as the structure of the isolated compounds have been ascertained on the basis of data obtained from elemental analyses (CHNM), spectral (UV-Vis., IR, mass and ¹H NMR) and thermal (TG and DTA) measurements. Some optical parameters such as indirect optical band gap and refractive index were estimated for the isolated compounds. The inhibitive properties of all synthesized hydrazones toward the corrosion of carbon-steel in 1 M HCl solutions were tested. The adsorption of hydrazone inhibitors on steel surface proceeded as a spontaneous first order reaction.</p

The Association of XRCC1 Gene Polymorphisms and Chronic Hepatitis C Induced Insulin Resistance in Egyptian Patients

Chronic hepatitis C is implicated in insulin resistance (IR) susceptibility. An X-ray repair cross-complementing group 1 gene (XRCC1) is proposed to be a candidate gene for a study of IR susceptibility. So, this study aims to investigate the possible association of the XRCC1 gene polymorphisms with the risk of IR related to chronic hepatitis C virus (HCV) infection in Egyptian patients. In a case-control study, a total of 210 subjects, including 140 chronic HCV patients (87 patients with IR and 53 without IR) and 70 healthy controls, were included. Two genetic polymorphisms (c.1254C &gt; T and c.1517G &gt; C) of the XRCC1 gene were genotyped via the PCR-restriction fragment length polymorphism (PCR-RFLP) technique. The result of the current study revealed that these two single nucleotide polymorphisms (SNPs) have statistically significant influences on susceptibility to IR in chronic HCV infected Egyptian patients. It could be concluded that c.1254C &gt; T, the TT genotype, CT/CC carriers as well as c.1517G &gt; C, the CC genotype and GC/GG carriers might be associated with increased IR susceptibility. Moreover, T-allele of c.1254C &gt; T and the C-allele of c.1517G &gt; C genetic variants might influence the susceptibility

Computer simulation for the seismic behaviour of bridge expansion joints enhanced with SMA: Case study

This paper concerns the study of the expansion joints of Benha Bridge under seismic loads. The seismic behaviour of its bridge expansion joints has been enhanced by shape memory alloy (SMA) dampers as a form of energy-dissipation device. SMA can dissipate a part of the input energy from the earthquake by generating a counterforce for the induced seismic force, allowing the opportunity to control the joint width and overcome pounding and unseating problems. In this research, MATLAB programs are developed to calculate the joint width responses in the two cases of without SMA and with SMA control devices embedded between adjacent bridge frames, which are modeled as a single degree of freedom system for each frame. Benha Bridge is the subject of this case study, which aims to check and validate the SMA parameter values that their charts have introduced from earlier research and to improve the seismic behaviour of bridge expansion joints by eliminating unseating and pounding problems. The results show that SMA dampers are able to control the joint width and absorb the excess forces caused by nearby expansion joint overlap. Furthermore, SMA design charts are applicable for bridges of multiple frames when they are homogenous in time periods

Remote Sensing, Petrological and Geochemical Data for Lithological Mapping in Wadi Kid, Southeast Sinai, Egypt

The Wadi Samra–Wadi Kid district in southeastern Sinai, Egypt, has undergone extensive investigation involving remote sensing analysis, field geology studies, petrography, and geochemistry. The main aim of this study is the integration between remote sensing applications, fieldwork, and laboratory studies for accurate lithological mapping for future mineral exploration in the study region. The field relationships between these coincident rocks were studied in the study area. Landsat-8 (OLI) data that cover the investigated area were used in this paper. The different rock units in the study area were studied petrographically using a polarizing microscope, in addition to major and trace analysis using ICP-OES tools. The Operational Land Imager (OLI) images were used with several processing methods, such as false color composite (FCC), band ratio (BR), principal component analysis (PCA), and minimum noise fraction (MNF) techniques for detecting the different types of rock units in the Wadi Kid district. This district mainly consists of a volcano-sedimentary sequence as well as diorite, gabbro, granite, and albitite. Geochemically, the metasediments are classified as pelitic graywackes derived from sedimentary origin (i.e., shales). The Al2O3 and CaO contents are medium–high, while the Fe2O3 and TiO2 contents are very low. Alkaline minerals are relatively low–medium in content. All of the metasediment samples are characterized by high MgO contents and low SiO2, Fe2O3, and CaO contents. The granitic rocks appear to have alkaline and subalkaline affinity, while the subalkaline granites are high-K calc-alkaline to shoshonite series. The alkaline rocks are classified as albitite, while the calc-alkaline series samples vary from monzodiorites to granites. The outcomes of this study can be used for prospecting metallic and industrial mineral exploration in the Wadi Kid district