The empirical and numerical design approaches are considered very important in the viable and efficient design of support systems, stability analysis for tunnel, and underground excavations. In the ...present research work, the rock mass rating (RMR) and tunneling quality index (Q-system) were used as empirical methods for characterization of rock mass based on real-time geological and site geotechnical data and physical and strength properties of rock samples collected from the alignment of tunnel. The rock mass along the tunnel axis was classified into three geotechnical units (GU-1, GU-2, and GU-3). The support systems for each geotechnical unit were designed. The 2D elastoplastic finite-element method (FEM) was used for the analysis of rock mass behavior, in situ and redistribution stresses, plastic thickness around the tunnel, and performance of the design supports for the selection of optimum support system among RMR and Q supports for each geotechnical unit of tunnel. Based on results, Q support systems were found more effective for GU-1 and GU-2 as compared to RMR support systems and RMR support systems for GU-3 as compared to Q support systems.
Abstract In this study five different complexes of Cu(II) were synthesized for the purpose of environmentally notorious mercury sensing and preliminary biological screening. Pyridine‐2,6‐dicarboxylic ...acid (also known as dipicolinic acid, and abbreviated as H 2 DPA), 3‐phenyl pyrazole (3‐ppz), 4‐iodo‐1 H ‐pyrazole (4‐ipz), 4‐nitropyrazole (4‐npz), 4‐bromopyrazole (4‐bpz), and 4‐chloropyrazole (4‐cpz) were chosen as potential ligands. The synthesized complexes labelled as 1 – 5 , namely Cu(DPA)(3‐ppz), Cu(DPA)(4‐ipz), Cu(DPA)(4‐npz), Cu(DPA)(4‐bpz), Cu(DPA)(4‐cpz), were proposed based on spectroscopic data (FTIR, TGA, and UV‐visible spectroscopy). These complexes feature C=O functionalities that are not involved in coordination and may be used for further applications. The isolated complexes were utilized for detecting Hg(II) ions in water samples. Various concentrations of Hg(II) ions were prepared for detection purposes, and changes in absorption concerning complexes 1 – 5 were determined using UV‐Visible spectroscopy. It was found that complexes 3 and 4 exhibit efficient sensing abilities towards Hg(II) ions. The antibacterial activities of complexes 1 – 5 were assessed against S. typhi and E. coli . The complexes 1 and 3 displayed good antibacterial activities against S. typhi (13.67, and 13.56 mm, respectively) while complexes 1 , 2 and 4 were found to be efficient against E. coli (11.6, 12.66, 11.31 mm, respectively). The absorption maxima of 2,2‐diphenyl‐1‐picryhydrazyl (DPPH) at 517 nm, considerably shifted upon addition of complexes 1 – 5 . The results reveal that the complexes possess potential free radical scavenging abilities.
In this study, the role of a locally available rice husk ash (RHA) in reducing early-age shrinkage of high performance concrete (HPC) after evaluating its pozzolanic reactivity was evaluated. The ...X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analyses were performed after burning rice husk to 700 and 950°C. Presence of relatively high deposits of amorphous siliceous phases in RHA at 700°C indicated its pozzolanic potential. Subsequently, this RHA was ground to desired fineness, followed by sieving through sieve No. 200. Eventually, the fine RHA was used as a substitute of cement in different percentages (10, 15, and 20%) to evaluate its influence in mitigating autogenous shrinkage in concrete. Prismatic concrete beams (100 × 100 × 800 mm) were cast to measure autogenous shrinkage along with cylinders (150 mm dia. x 300 mm height) to test compressive strength of concrete. The results indicated a slight increase in compression strength with addition of 10% RHA, which however, reversed and slightly reduced in concretes containing 15 and 20% RHA. Unlike strength results, the trend of autogenous shrinkage was rather uniform as the rate as well as the amount of early-age autogenous shrinkage continued to decrease with increasing percentage of RHA. Moreover, despite of reduced rate during first 24 h, thereafter, the effect of 20% RHA on further reduction of autogenous shrinkage was insignificant and ended up only slightly lesser than the 15% RHA concrete at 7 days. Finally, the control cement sand mortar and mortar containing 15% RHA were cast to further validate the pozzolanic reactivity of RHA through scanning electron microscopy (SEM), EDX, and thermogravimetric analysis (TGA) tests. An observation of reduced amount of calcium hydroxide (Ca(OH)2) in RHA mortar samples indicating its excellent pozzolanic potential when used as a partial substitute of cement in HPC.
Pounding occurs when the adjacent buildings start vibration out of phase during the seismic activity which causes collision amongst the adjacent buildings. There are many mitigation techniques to ...avoid or minimize the effects of pounding including the provision of minimum separation gap between the adjacent buildings. Although all codes have provided the minimum separation gap requirements for the buildings, still a lot of study is required on this topic. This research aims at finding the minimum gap requirement for midrise buildings in Pakistan. Adjacent Buildings with different geometry and height are modelled in Sap2000 software with varying gap elements. Pushover and In-elastic time history analysis of these buildings are carried out using ground motion of Kashmir earthquake. Buildings are assumed to be resting on stiff soil. Material and sectional properties are also remained same for all cases. In order to reduce the pounding effects of two buildings, they were attached with each other and top displacements of buildings were compared with separate buildings with inadequate gap. Column shear, maximum peak displacements and square root of sum of squares of maximum peak displacements were studied and the results were plotted graphically. It was found out that pounding can occur up to separation gap of six inch. Maximum pounding occurs at the top floor level of smaller building. The requirement for minimum gap in UBC 97 is found out to be conservative.
Signaling mechanisms of NO-mediated host defense are yet to be elucidated. In this study, we report a unique signal pathway for cytoprotection during Salmonella infection that involves heme oxygenase ...1 (HO-1) induced by a nitrated cyclic nucleotide, 8-nitroguanosine 3',5'-cyclic monophosphate (8-nitro-cGMP). Wild-type C57BL/6 mice and C57BL/6 mice lacking inducible NO synthase (iNOS) were infected with Salmonella enterica serovar Typhimurium LT2. HO-1 was markedly up-regulated during the infection, the level being significantly higher in wild-type mice than in iNOS-deficient mice. HO-1 up-regulation was associated with 8-nitro-cGMP formation detected immunohistochemically in Salmonella-infected mouse liver and peritoneal macrophages. 8-Nitro-cGMP either exogenously added or formed endogenously induced HO-1 in cultured macrophages infected with Salmonella. HO-1 inhibition by polyethylene glycol-conjugated zinc-protoporphyrin IX impaired intracellular killing of bacteria in mouse liver and in both RAW 264 cells and peritoneal macrophages. Infection-associated apoptosis was also markedly increased in polyethylene glycol-conjugated zinc-protoporphyrin IX-treated mouse liver cells and cultured macrophages. This effect of HO-1 inhibition was further confirmed by using HO-1 short interfering RNA in peritoneal macrophages. Our results suggest that HO-1 induced by NO-mediated 8-nitro-cGMP formation contributes, via its potent cytoprotective function, to host defense during murine salmonellosis.
•Hydraform Blocks.•Mechanical Properties.•Unconfined Dry Stacked Block Masonry.•Quasi-Static Cyclic Test.•Seismic Performance.
Dry stacked block masonry is getting popularity and has auspicious ...future both in developed and developing countries. In this research work, it was aimed to appraise the seismic performance of unconfined dry stacked block masonry structure built with Hydraform blocks. The experimental work included the construction of a full-scale typical building and testing by using quasi-static reverse cyclic loading. The seismic parameters and behavior studied in this research work, include the force–deformation relationship, ultimate ductility factor, response modification factor, displacement amplification factor, energy dissipation, stiffness degradation, and structural performance levels. The visual assessment and analyses of the test data was scrutinized to construe and elucidate the damage patterns, and local and global behavior of the structure. Based on the results, the unconfined dry stacked block masonry structures can easily withstand against low to moderate seismic actions. The tolerance of self-interlocking blocks, in sliding and rotation in out-of-plane direction, enables it to act as energy dissipating devices and mitigates the chances of brittle shear failure.
Coordination complexes (1–4) of 2-amino-4-methylbenzothiazole and 2-amino-3-methylpyridine with Cu(CH3COO)2 and AgNO3 were prepared and characterized by UV/Vis and FT-IR spectroscopy. The molecular ...structure for single crystals of silver complexes (2 and 4) were determined by X-ray diffraction. The coordination complex (2) is monoclinic with space group P21/c, wherein two ligands are coordinated to a metal ion, affording distorted trigonal geometry around the central Ag metal ion. The efficient nucleophilic center, i.e., the endocyclic nitrogen of the organic ligand, binds to the silver metal. Ligands are coordinated to adopt cis arrangement, predominantly due to steric reasons. The O(2) and O(3) atoms of the NO3− group further play an important role in such type of ligand arrangement by hydrogen bonding with the NH2 group of ligands. Complex (4) is orthorhombic, P212121, comprising two molecules of 2-amino-3-methylpyridine as ligand coordinated with the metal ion, affording a polymeric structure. The coordination behavior of the ligand is identical to that in complex 2, wherein ring nitrogen is coordinated to the metal center and bridged to another metal ion through an NH2 group. The resulting product is polymeric in nature with the Ag metal in the backbone and ligand as the bridge. Compounds (2–4) were found to be luminescent, while 1 did not show such activity. All compounds were screened for their preliminary biological activities such as antibacterial, antioxidant and enzyme inhibition. Compounds exhibited moderate activity in these tests.
This study investigated the characteristics of iron corrosion scales in pipes at tube well, overhead tank, and consumers’ end in older untreated water distribution system in Peshawar city, Pakistan. ...Effect of water quality conditions on corrosion scales and that of scales on drinking water quality in such systems was also assessed by undertaking a comparison with new piped distribution systems. The scales were analyzed for chemical composition and morphology using X-ray diffraction (XRD), inductively coupled plasma (ICP), and a scanning electron microscope (SEM), while water quality was examined for physicochemical and biological characteristics. The main crystalline phases of corrosion scales were goethite, magnetite, siderite, and quartz. From tube well to consumers’ end, goethite increased from 36 up to 48%, quartz declined from 22 to 15%, while magnetite fluctuated and siderite disappeared. Elemental composition of scales showed the deposition of Zn, Al, Mn, Cr, Pb, Cu, As, and Cd with Zn (13.9 g/kg) and Al (3.6 g/kg) in highest proportion. The SEM analysis illustrated the presence of microbial communities indicating the formation of biofilms in the corrosion scales. The significant difference (
P
< 0.05) in levels of dissolved oxygen (DO), Cl
−
, SiO
4
4−
, electrical conductivity (EC), SO
4
2−
, NO
3
−
, alkalinity, hardness, and trace metals between old (DS-O) and new piped systems indicated their role in corrosion scale formation/destabilization and the effect of scale dissolution on water quality. In DS-O, EC, Cu, and Mn were significantly higher (
P
< 0.05), whereas turbidity, EC, DO, and SiO
4
4−
significantly increased from source to consumers’ end implying a higher dissolution of scales and lowered corrosion rates in DS-O to utilize SiO
4
4−
and DO for iron oxidation.
Reaction of the 1,3-diisobutyl thiourea (L) with MX M = Cu, Ag and X = Cl, NO3 provide polynuclear heteroleptic complexes Cu3L3Cl3 (1), Ag2L6(NO3)2 (2) and Ag6L8Cl4 (3). All complexes were ...characterized by single crystal X-ray diffraction. The solid-state crystal of these complexes (1–3) were determined by single crystal XRD. Which shows that complex (1) is tri-nuclear with trigonal planer arrangement, complex (2) is binuclear with four membered metalacyclic ring and complex (3) is hexa-nuclear. Complexes (1–3) are tested for their free radical scavenging activity by using 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH) showing moderate potential.
PDF
