Showing papers by "M. S. Alam published in 2022"

Polar and nonpolar iron (II) complexes of isatin hydrazone derivatives as effective catalysts in oxidation reactions and their antimicrobial and anticancer activities

Abstract: Two iron (II) complexes of various derivatives (polar with 5-sodium sulfoante group and nonpolar with di-tert butyl groups, HLSO3Na and HLDBu, respectively) of isatin hydrazones were synthesized within 1:2 molar ratios of Fe2+ ion to the isatin hydrazone ligand giving Fe (LSO3Na)2 and Fe (LDBu)2, respectively. The polar and nonpolar isatin hydrazone derivatives behaved as O,N,O-tridentate pincer chelating agents with Fe2+ ions. The variation in polarity of the two Fe2+-complexes controlled their catalytic action in the oxidation of alcohols using tBuOOH (tert-butyl hydroperoxide). The polar catalyst showed more enhanced catalytic behavior than that of the nonpolar one. The optimized conditions for Fe (LDBu)2 was found to be better at 70°C after 4 h with 86% of benzaldehyde than that with Fe (LSO3Na)2 (at 90°C after 2 h with 84% of benzaldehyde). Their kinetic studies were used to derive the thermodynamic parameters of Ea and ΔG# for the catalytic processes. Biologically, based on their high reactivity toward some bacterial and fungal strains and some human cancer cell lines, the calf thymus-DNA (ctDNA) interaction of the current compounds were studied. The nonpolar Fe2+-complex (Fe (LDBu)2) assigned more reactivity with ctDNA more than that of the polar reagent (Fe (LSO3Na)2) and also more than that of their uncoordinated ligands depending on their lipophilicity. Their reactivities toward ctDNA was established spectrophotometrically and within the changes in the DNA solution viscosity. The binding strength was evaluated with the magnitudes of the binding constant (Kb = 3.03, 3.21, 9.79, and 11.51 × 108 mol−1 dm3 for HLDBu, HLSO3Na, Fe (LDBu)2, and Fe (LSO3Na)2, respectively), which supported by the Gibbs' free energy values −3.12, −31.42, −34.18, and −34.58 kJ mol−1, respectively.

Comparable catalytic and biological behavior of alternative polar dioxo-molybdenum (VI) Schiff base hydrazone chelates

Abstract: According to the appreciable catalytic and biological reactivity of Mo-chelates with various based arylhydrazone organic framework, two dioxide-molybdenum (VI) chelates are produced with distinct polarity (MoL1, with high polar character and MoL2, with low polar feature). Both Mo-pincer chelates are synthesized in equimolar ratios to their corresponded coordinated ligands (Schiff base hydrazone derivatives), resulting octahedral structures, which identified by alternative spectral techniques. The novelty here is the first attempt to study the catalytic action of both Mo-chelates in the brominative decarboxylation of α,β-cinnamic acid to the selective bromo-styrene product using hydrogen peroxide and potassium bromide at room temperature under homogeneous aerobic atmosphere (i.e. water). Comparable biological studies are based on the antimicrobial and anticancer assays, as well as, the ctDNA (calf thymus DNA) interaction, which investigated using various spectroscopic tools. According to the various polarity of the Mo-chelate catalysts, the high polar Mo-chelate (MoL1) has a better catalytic behavior for the yield of the selective product of 2-bromo-styrene derivative more than that of the less-polar Mo-chelate (MoL2), when water is used as the solvent. MoL1 and MoL2 optimize the catalytic system with 94 and 91% of the 2-bromo-product with 30 and 60 min, respectively. A mechanistic pathway is proposed to distinguish the role of Mo6+ ion for enhancing such catalytic processes spectroscopically. Based on the Tweedy's chelation theory, the effect of Mo6+ ion in their chelates is attributed by high antimicrobial and anticancer action, The interaction ctDNA is estimated with determination of the binding constants, Kb, and the negative values of Gibbs’ free energy, ΔGb≠, for both Mo-chelates depending on the spectroscopic shifts and changes.

Seismic evaluation of friction spring‐based self‐centering braced frames based on life‐cycle cost

Abstract: In recent decades, a variety of self‐centering braces (SCBs) have been developed to address the limitations of conventional frames by decreasing residual drift due to earthquakes. However, the initial construction cost of self‐centering (SC) structures is expected to be higher and the study about its cost‐effectiveness over the life‐cycle span is limited. This paper presents a seismic life‐cycle cost evaluation of emerging friction spring‐based self‐centering braced frames (SCB‐Fs) compared with traditional buckling restrained braced frames (BRB‐Fs) when an existing structure is upgraded. Particular focus is on the effect of residual deformation, initial construction cost, and high fatigue performance of the SCB. Following the performance‐based design of the SCB‐F and BRB‐F, system‐level analyses are conducted. Numerical results of case‐study buildings indicate that the total expected annual loss (EAL) of the BRB‐F increases by approximately three times when the effect of residual deformation is considered, while its effect on the total EAL of the SCB‐F is negligible. Besides, the superior performance of the SCB‐F compared to BRB‐F is highlighted by a substantial reduction in EAL induced by earthquakes. In addition, the acceleration‐related seismic losses of SCB‐F constitute approximately 44% of the total EAL. Its contribution is significantly larger in the case of the SCB‐F compared to the BRB‐F. From the perspective of economic benefit, increasing the structural life‐cycle span is beneficial to the SCB‐F compared to the BRB‐F. The high fatigue performance of the SCB is favorable to increase the economic benefit of the SCB‐F, especially when the reduction of repair time is considered. The economic benefit of the SCB‐F compared to the BRB‐F is highly related to the initial construction cost. Taking the 100 years as an expected life‐cycle span, the high initial construction cost of the SCB‐F would not be paid off when the unit cost of the SCB is about 2.1 times that of the BRB.

Simplified Predictive Expressions of Drift Limit States for Reinforced Concrete Circular Bridge Columns

Abstract: A critical component of performance-based design (PBD) is the quantification of damage states in terms of engineering demand parameters (EDPs). One of the most widely used EDPs to define damage states of reinforced concrete bridge columns is the drift ratio. Here, a fiber-based numerical model was validated by comparing its damage predictions against experimental results for large-scale tests of reinforced concrete columns subjected to reversed cyclic loading. The Monte Carlo sampling technique was adopted to generate 1,000 well-confined and flexure-dominated concrete columns, each having a unique combination of aspect ratio, axial-load ratio, longitudinal and spiral reinforcement ratios, and concrete and reinforcing steel yield strengths. The columns were analyzed numerically under static pushover loading, and the drift ratios corresponding to various strain limits were recorded. The resulting data were fit to mathematical expressions through machine learning–based symbolic regression. The proposed simplified expressions well predicted the drift ratios obtained from the numerical analysis with a minimum square of the correlation coefficient of 0.88. Also, the predicted drift ratios from the proposed expressions were comparable to those measured experimentally at key damage states, such as concrete cover spalling, concrete core crushing, and bar buckling. In particular, the predictions of the proposed expression at rebar buckling, which was based on a reinforcing steel tensile strain of 0.05, were more accurate than two widely used expressions found in the literature. Finally, the application of the proposed expressions within the context of PBD was demonstrated by a numerical example. The proposed simplified expressions are not intended to replace pushover or nonlinear time history analyses as part of the PBD, but rather provide approximate predictions of the limit states, which would significantly facilitate the development of appropriate preliminary designs, especially at early design stages. In addition, since the predictions of the proposed expressions were validated using previous experimental data, they can serve as a benchmark for the bridge engineering community when determining the limit states of reinforced concrete columns through numerical analyses.

Seismic performance upgrade of substandard RC buildings with different structural systems using advanced retrofit techniques

Abstract: There has been ongoing deliberation to arrive at promising retrofit strategies for pre-seismic code reinforced concrete (RC) structures. Against this backdrop, the research reported in this study puts forth solutions by focusing on advanced retrofit approaches for improving the seismic performance of substandard RC buildings with structural systems common to medium seismicity regions. High-performance reinforced concrete (HPRC) jacket application and self-centering energy dissipative (SCED) braces are the contemporary retrofit alternatives prioritized in this study to upgrade RC structural systems deficient in stiffness, strength and/or ductility. While these retrofit techniques were previously investigated at the member level, this study focuses on implementing thin-HPRC jacket applications, innovative outrigger-belt truss SCED bracing systems , and hybrid approaches on three-dimensional (3D) fiber-based numerical models representing substandard RC structures with different heights. Inelastic pushover analyses and multi-record dynamic response simulations are conducted to assess the retrofit alternatives by monitoring several local damage indices (LDIs) and the related global damage measure (GDM). The study confirms the effectiveness of retrofit measures for a moment-resisting frame building (MRF) deficient in lateral capacity and a high-rise shear wall (SW) building with insufficient global ductility. The presented systematic methodology accounts for the redistribution of seismic demands after retrofitting critical elements and enables selecting effective seismic retrofit solutions, namely SCED bracing system for MRF structure and hybrid retrofit for the high-rise SW building, using probabilistic seismic performance assessment along with cost and practical considerations. • Systematic seismic assessment and retrofit methodology. • HPRC jacket and SCED brace retrofit techniques applied on substandard RC buildings. • Innovative outrigger-belt truss system and hybrid retrofit configurations. • 3D fiber-based models with retrofit techniques verified against test results. • Prioritization of retrofit selection based on performance enhancement and cost.

Promoted catalytic potential in sulfides oxidation and biological screening of green Pd (II) and Co (II) complexes of salicylidene isatin hydrazone ligand

Abstract: Mononucleating complexes of isatin hydrazone sodium sulfonate ligand (HLn) with palladium (II) and cobalt (II) ions: The complexes were synthesized within 1:1 and 2:1 molar ratio of HLn with Pd2+and Co2+ion in PdLn and Co (Ln)2, respectively. The catalytic reactivity of both complexes was examined in the oxidation of sulfides (diphenyl sulfide, dps, and methylphenyl sulfide, mps) using hydrogen peroxide under aerobic conditions. Oxoproducts, dipheylsufoxide, dpo, and methyl phenyl sulfoxide, mpo, are the chemoselective products with detection of large amounts of the unselective further oxidation products of dioxoproducts (dipheylsufone, dpn, and methylphenyl sulfone, mpn). The homogenous catalyst of Co (Ln)2revealed more efficient action compared to that of PdLn depending on the high electrochemical reversible potential of the central metal ion in the catalytic reaction within the electron and/or oxygen transfer system. Exploring the importance of the M2+ion in the coordinated ligand, the bio-reactivity of HLn, PdLn, and Co (Ln)2was illustrated within some commonly well-known bacteria and fungi strains. Additionally, they were involved as anticancer reagents against some human cancer cell lines in vitro. Both metal complexes presented high inhibited action versus the growth of the studied microorganism and cancer. The interaction effect of Pd2+and Co2+ions in their pincer complexes was tested with calf thymus DNA spectroscopically and via the viscosity changes.

Compression tests of thin-walled cold-formed steel columns with Σ-shaped sections and patterned perforations distributed along the length

Abstract: The North American design specification of AISI S100 (2016) incorporates the Direct Strength Method (DSM) to design cold-formed steel members with perforations under compression. However, the literature review showed that (i) the DSM has been used for nearly a decade, but the accuracy of the method is still not fully understood and (ii) although numerous studies concerning compression tests of cold-formed steel members with perforations have been conducted, only limited experimental data is accessible to the readers due to confidentiality issues. This study aimed at making efforts towards resolving the two issues. First, thin-walled roll-formed steel columns (count = 46) with three different Σ-shaped sections and six different lengths were tested under compression, where the columns were perforated and mostly tested with pinned ends. The column axial strengths and stiffnesses, failure modes, and structural responses under compression are reported in this paper. Then, the parameters required by the DSM for estimating the axial strengths of these columns were determined, and the results are also reported in this paper. Finally, the accuracy of the DSM was assessed with the tested axial strengths of the columns. It was found that the DSM could not accurately estimate the axial strengths of the columns rather these estimates were unconservative.

Finite-Element Simulation of the Lateral Response of Posttensioned Base Rocking Steel Bridge Piers

Abstract: This paper presents the results of a finite-element (FE) study on posttensioned (PT) rocking steel bridge piers, each composed of a circular tubular column, welded end plates, PT strands, and axially yielding steel energy dissipators (EDs), and corresponding chairs. The pier is configured so that it rocks at its base. Previously conducted experiments on five scaled rocking steel columns are summarized. Three-dimensional (3D) continuum FE models of the tested specimens are generated with the objective of verifying the capability of the modeling approach in the simulation of the local and global responses. Strain-controlled cyclic coupon tests were performed to quantify the kinematic and isotropic hardening material parameters. A simplified method is proposed to model the cyclic loss of prestressing because of wedge seating in a typical industry monostrand anchorage system. The FE procedure is then calibrated against the experimental data at the material, component, and global pier levels. A parametric study is conducted to examine the effects of key factors such as material model, P-Delta, base plate dimensions, column diameter-to-thickness and initial axial force ratios, ED chairs, and ED location on the lateral cyclic response. It is demonstrated that, for a given target drift, local buckling and the resulting residual lateral deformations of a rocking steel pier are a function of the diameter-to-thickness and initial axial force ratios of the column and the ED chairs. By the proper selection of these variables, a stable and robust self-centering response can be obtained with minimal damage to the bridge pier.

Life Cycle Thinking–Based Decision Making for Bridges under Seismic Conditions. II: A Case Study on Bridges with Superelastic SMA RC Piers

Abstract: Bridges reinforced with superelastic shape memory alloys (SMAs) demonstrate improved performance under earthquake excitations. In general, the capital investment for a bridge reinforced with SMAs is higher due to their high cost and special workmanship requirement. However, when accounting for postearthquake repair and maintenance costs and environmental impacts, SMA-reinforced bridges can deliver significant economic and environmental advantages over conventional structures in the long run. Based on a life cycle thinking–based decision support framework developed in a companion paper, this study thoroughly evaluated the life cycle seismic performance of a bridge reinforced with an SMA considering three different reinforcement configurations. Fragility analyses were conducted for each reinforcement configuration of the SMA-reinforced concrete (RC) bridge to assess its seismic vulnerability. A life cycle cost (LCC) assessment was performed to determine the economic impacts during their service life. Additionally, cradle-to-grave life cycle assessment (LCA) was done using SimaPro to assess the environmental impacts. Using the outcomes of the these assessments, the overall life cycle performance of the novel bridges was compared with a similar bridge reinforced with conventional steel. The results showed that the SMA-reinforced bridges presented a better seismic life cycle performance compared with a conventional RC bridge from a seismic performance and economic perspective. However, the conventional bridge showed a better overall score from an eco-friendly approach.

Forced Convective Heat Transfer Coefficient Measurement of Low Concentration Nanorods ZnO–Ethylene Glycol Nanofluids in Laminar Flow

Abstract: This paper presents the experimental forced convective heat transfer coefficient (HTC) of nanorods (NRs) zinc oxide–ethylene glycol nanofluids (ZnO–EG NFs) in laminar flow. First, ZnO NRs were synthesized using a hydrothermal method that uses zinc acetate dihydrate [Zn(CH3COO)2·2H2O] as a precursor, sodium hydroxide as a reducing agent, and polyvinylpyrrolidone (PVP) as a surfactant. The hydrothermal reaction was performed at 170 °C for 6 h in a Teflon-lined stainless-steel tube autoclave. The sample’s X-ray diffraction (XRD) pattern confirmed the formation of the hexagonal wurtzite phase of ZnO, and transmission electron microscopy (TEM) analysis revealed the NRs of the products with an average aspect ratio (length/diameter) of 2.25. Then, 0.1, 0.2, and 0.3 vol% of ZnO–EG NFs were prepared by adding the required ZnO NRs to 100 mL of EG. After that, time-lapse sedimentation observation, zeta potential (ζ), and ultraviolet-visible (UV–vis) spectroscopy was used to assess the stability of the NFs. Furthermore, the viscosity (μ) and density (ρ) of NFs were measured experimentally as a function of vol% from ambient temperature to 60 °C. Finally, the HTC of NFs was evaluated utilizing a vertical shell and tube heat transfer apparatus and a computer-based data recorder to quantify the forced convective HTC of NFs in laminar flow at Reynolds numbers (Re) of 400, 500, and 600. The obtained results indicate that adding only small amounts of ZnO NRs to EG can significantly increase the HTC, encouraging industrial and other heat management applications.

Square-Wave and Cyclic Voltammetry of Native Proanthocyanidins Extracted from Grapevine (Vitis vinifera) on the Glassy Carbon Electrode

Abstract: Condensed tannins are short polymers of flavan-3-ols found in grapes (also known as proanthocyanidins). An investigation on the electrochemical oxidation of grapevine proanthocyanidins (PAs) on glassy carbon electrodes under various conditions was conducted for the first time. To study how the proanthocyanidins were oxidized, square-wave and cyclic voltammetry were used. There is a predominant oxidation peak associated with the extract of proanthocyanidins, and this can be attributed to the oxidation of catechol 3′,4′-dihydroxyl groups, which can form their oxidation peak. There are two electrons and two protons involved in the oxidation of the catechol group, which must be kept in mind when considering the oxidation of the catechol group. On the glassy carbon electrode (GCE), the PAs extracted from grapevine are oxidized by an adsorption-dependent mechanism as they interact with the GCE surface. As a result, it was found that the anodic peak current varied linearly with PAs’ concentrations in the range of 4 to 50 ppm, with a detection limit of 3.07 ppm (S/N = 3). There was a development in the surface concentration of the oxidation products at the GC electrode; as the scans progressed, the surface concentration of oxidation products at the electrode remained at 4.83 × 10−11 mol cm−2, indicating that they were immobilized on the GCE as oxidation products adsorbed on the electrode.

How Do Immigrant Family Businesses Achieve Global Expansion? An Embeddedness Perspective

Abstract: Extant literature on immigrant family businesses (IFBs) refers to the vital role of embeddedness in their success. Yet, little is known about how embeddedness evolves from family to global and how it helps IFBs to establish themselves in a host country, survive the related challenges, and thrive in the international market. By drawing on the lived experience of 25 highly successful family business entrepreneurs in Australia, we develop an integrated process model and discover a four-phase chronology of IFBs’ success toward global expansion: arriving, establishing, expanding, and thriving. Further, this model links these transitory phases to the IFBs’ embeddedness that evolves from family to local, host-country, and global. Our findings suggest that while the strength of family embeddedness is critical over time, its scope is limited as the IFBs form new, more extensive networks toward the global market. IFBs act as boundary spanners, blending local and international resources to create value. The theoretical and practical implications of our findings are shared in the concluding section. Keywords: Immigrant family business; embeddedness; process model; global strategy

Drift Ratio Limit States for Circular Concrete Columns Reinforced with Different Types of High-Strength Steel Reinforcing Bars

Abstract: A prime reason for the restricted use of high-strength steel (HSS) rebar as the main reinforcement in concrete columns in seismic regions is the lack of appropriate seismic design guidelines. Within the context of performance-based seismic design of concrete bridge columns, it is critical to identify drift ratios corresponding to the initiation of different types of damage states. Such drift ratios, which are often referred to as drift ratio limit states, do not seem to exist for concrete columns reinforced with HSS. In this study, a comprehensive analytical program with an overarching objective of proposing simplified expressions to predict drift ratio limit states for circular concrete columns reinforced with HSS was carried out. Factorial analysis was initially performed to quantify the effects of geometry-, section-, and material-related parameters on the drift ratio limit states, and then identify the parameters with significant contributions. To generate a sufficient amount of data for the development of the drift ratio limit states expressions, the Monte Carlo sampling technique was adopted. Three samples each consisting of 1,000 unique columns, were generated for three types of HSS. The columns were analyzed under displacement-controlled quasi-static cyclic loading, and the drift ratios at the onset of the damage states were recorded. The resulting data were first used to establish the drift ratio limit states on a probabilistic basis. Machine learning-based symbolic regression was then employed to establish relationships between the variable parameters and the drift ratio limit states. To maintain simplicity, the proposed expressions contained only parameters deemed significant following the factorial analysis. The proposed simplified expressions for concrete columns reinforced with ASTM A706 Grade 550 had the highest square of correlation coefficients. The proposed simplified expression provided adequate predictions of the drift ratio limit states obtained from the numerical analysis as well as those measured in previous experimental programs.

Two ionic oxo‐vanadate and dioxo‐molybdate complexes of dinitro‐aroylhydazone derivative: effective catalysts towards epoxidation reactions, biological activity, ct DNA binding, DFT and silico investigations

Abstract: To meet the ecological demand for synthesis of ecofriendly metalated organic compounds, two new green dinitro-aroylhydrazone derivatives (HLZNa) were used for the synthesis of vanadate(IV) and cis-molybdate(VI) complexes (VOLZNa and MoO2LZNa). The N,O-bidentate ligand and its M-pincer chelates were characterized using various spectroscopic tools. Infrared spectra exhibited a high shift of the CH=N band with the disappearance of the O–H band of HLZNa after its coordination with V4+ and Mo6+ in VOLZNa and MoO2LZNa, respectively. 1H NMR spectra supported this observation for HLZNa compared with that of MoO2LZNa for the spectral signal of CH=N and O–H groups. In the UV–Vis. spectra, VOLZNa showed an additional spectral band at 741 nm for the d → d transition, which accomplished such complexation. Catalytically, VOLZNa exhibited slightly more catalytic action, with 92% yield after 2 h, compared with the MoO2LZNa catalyst (4 h with 92% yield) in the oxygenation of 1,2-cyclooctene, that is, the epoxidation, at 90 °C. A strong reversible electrochemical behavior of VOLZNa (V4+/V5+redox couple) enhanced the catalytic action of VOLZNa over MoO2LZNa, which is supported by spectroscopic analysis. The biological behavior of HLZNa, VOLZNa, and MoO2LZNa was examined through their binding ability to ctDNA via UV–Vis. spectroscopy and hydrodynamic measurements. Spectroscopically, the derived binding constant of VOLZNa and MoO2LZNa (Kb = 4.45 and 5.01 × 108 mol−1 dm3, respectively) was higher than that of the free ligand (HLZNa, 2.88 × 108 mol−1 dm3), which is attributed to their reactivity toward ctDNA. Also, the Gibbs free energy values ( ∆ G b ≠ ) for such an interaction illustrated their high potential against ctDNA over their ligand (−31.14, −32.22, and −32.52 kJ/mol for HLZNa, VOLZNa, and MoO2LZNa, respectively). The metal ions (V4+ and Mo6+) in VOLZNa and MoO2LZNa, respectively, improved their antioxidant, antimicrobial, and antitumor activities over the free ligand. The structures of the current compounds were further elucidated using the DFT/B3LYP method, which confirmed the mode of bonding depending on the distribution of the coordinating functional groups. Some physical parameters were estimated to evaluate the probability of these compounds' reactivity biologically and catalytically. The catalytic role of the MoO2LZNa complex was confirmed computationally. The in vitro obtains regarding the antimicrobial activity of the M-chelates were tested using in silico approaches. The outcomes reflected the high conformity of VOLZNa as an effective antimicrobial reagent.

Measurement report: Interpretation of wide-range particulate matter size distributions in Delhi

Abstract: Abstract. Delhi is one of the world's most polluted cities, with very high concentrations of airborne particulate matter. However, little is known about the factors controlling the characteristics of wide-range particle number size distributions. Here, new measurements are reported from three field campaigns conducted in winter and pre-monsoon and post-monsoon seasons at the Indian Institute of Technology campus in the south of the city. Particle number size distributions were measured simultaneously, using a scanning mobility particle sizer and a GRIMM optical particle monitor, covering 15 nm to >10 µm diameter. The merged, wide-range size distributions were categorized into the following five size ranges: nucleation (15–20 nm), Aitken (20–100 nm), accumulation (100 nm–1 µm), large fine (1–2.5 µm), and coarse (2.5–10 µm) particles. The ultrafine fraction (15–100 nm) accounts for about 52 % of all particles by number (PN10 is the total particle number from 15 nm to 10 µm) but just 1 % by PM10 volume (PV10 is the total particle volume from 15 nm to 10 µm). The measured size distributions are markedly coarser than most from other parts of the world but are consistent with earlier cascade impactor data from Delhi. Our results suggest substantial aerosol processing by coagulation, condensation, and water uptake in the heavily polluted atmosphere, which takes place mostly at nighttime and in the morning hours. Total number concentrations are highest in winter, but the mode of the distribution is largest in the post-monsoon (autumn) season. The accumulation mode particles dominate the particle volume in autumn and winter, while the coarse mode dominates in summer. Polar plots show a huge variation between both size fractions in the same season and between seasons for the same size fraction. The diurnal pattern of particle numbers is strongly reflective of a road traffic influence upon concentrations, especially in autumn and winter, although other sources, such as cooking and domestic heating, may influence the evening peak. There is a clear influence of diesel traffic at nighttime, when it is permitted to enter the city, and also indications in the size distribution data of a mode < 15 nm, which is probably attributable to CNG/LPG vehicles. New particle formation appears to be infrequent and is, in this dataset, limited to 1 d in the summer campaign. Our results reveal that the very high emissions of airborne particles in Delhi, particularly from traffic, determine the variation in particle number size distributions.

Design, Characterization, and Immune Augmentation of Docosahexaenoic Acid Nanovesicles as a Potential Delivery System for Recombinant HBsAg Protein

Abstract: Recombinant HBsAg-loaded docosahexaenoic acid nanovesicles were successfully developed, lyophilized (LRPDNV) and characterized for their physico-chemical properties. The zetapotential (ZP) of LRPDNV was −60.4 ± 10.4 mV, and its polydispersity (PDI) was 0.201, with a % PDI of 74.8. The particle sizes of LRPDNV were 361.4 ± 48.24 z. d.nm and 298.8 ± 13.4 r.nm. The % mass (r.nm) of LRPDNV in a colloidal injectable system was 50, its mobility value was −3.417 µm cm/Vs, while the conductivity of the particles was 0.728 (mS/cm). Transmission electron microscopic (TEM) analysis showed smooth morphological characteristics of discrete spherical LRPDNV. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) of LRPDNV revealed that LRPDNV is thermostable. The X-ray diffraction (XRD) studies showed a discrete crystalline structure of LRPDNV at 2θ. Nuclear magnet resonance (NMR) studies (1H-NMR and 13C-NMR spectrum showed the discrete structure of LRPDNV. The immunogenicity study was performed by antibody induction technique. The anti-HBs IgG levels were elevated in Wistar rats; the antibody induction was observed more in the product (LRPDNV) treatment group when compared to the standard vaccine group. The level of antibodies on the 14th and 30th day was 6.3 ± 0.78 U/mL and 9.24 ± 1.76 U/mL in the treatment and standard vaccine groups, respectively. Furthermore, the antibody level on the 30th day in the treatment group was 26.66 ± 0.77 U/mL, and in the standard vaccine group, the antibody level was 23.94 ± 1.62 U/mL. The LRPDNV vaccine delivery method released HBsAg sustainably from the 14th to the 30th day. The results of this study indicate the successful formulation of DHA nanovesicles which have great potential as an adjuvant system for the delivery of recombinant HBsAg protein.

Seismic response sensitivity and optimal design of an isolated multi-span continuous highway bridge with self-centering SMA RC bridge piers and superelastic SMA restrainers

Abstract: The use of superelastic shape memory alloy (SMA) in reinforced concrete (RC) pier and restrainers between girder and pier/abutment has been proposed in an earlier study to improve the seismic performance of highway bridges. This paper aims at identifying the significant factors that affect the seismic response of such a novel bridge system. A sequential fractional factorial design method is performed to statistically evaluate the effects of six design factors (three geometry-related and three material-related) as well as their interactions. Additionally, a multi-criteria optimization technique is implemented to determine the most efficient combination of the design parameters for SMA RC piers and SMA restrainers. Results demonstrate that the geometry-related factors and their interactions have large effects (with a contribution greater than 91%) on the relative displacement between the girder and pier. The target residual drift of the pier, design target displacement of the restrainer, and their interaction are the three most significant factors (with contributions approximately 30%–68%) affecting the base shear of the pier. The residual drift of the pier is sensitive to the design target displacement of the restrainer, its interaction with the forward transformation stress of SMA, and material-related factors with regard to the energy dissipation of SMA.

Deep Framework for Predicting COVID-19 and Related Lung diseases using CXR Images

Abstract: Along with a health crisis, COVID-19 has also led the world towards an economical barrier. So far the virus has effected approximately 400 Millions causing 5 Million deaths and is expanding everyday. There is an urge to stop the exponential growth of the contagious disease, only possible through an early diagnosis of the disease. Currently, several testing techniques are being used to diagnose COVID-19, among them Polymerase Chain Reaction (PCR) is a gold standard globally. However, due to it’s processing time, cost and less sensitivity towards COVID-19, physicians suggest to correlate the results with radiological tests preferably Chest X-Ray (CXR) imaging since it consumes less time and is more sensitive towards COVID-19. To overcome the pandemic many research groups have been working on the solution. Several Computer Aided Diagnostic (CAD) systems have been proposed by the researchers however, they lack robustness and stability towards blind datasets. Moreover, majority of the CAD systems provide binary classification between healthy and COVID-19, various lung abnormalities resembles COVID-19 in terms of their structural appearance and can be falsely classified as COVID-19. In this paper, we have proposed a deep model using EfficinetNet-B0 as a baseline model. Our proposed model has been trained on the largest available CXR dataset of COVID-19 comprising CXR images of normal, Viral Pneumonia, Lung Opacity and COVID-19 effected lungs and yielded an accuracy of 99.46%. Proposed model has been blind tested on four publicly available datasets achieving highest accuracy of 99.96%. Furthermore, the model is transfer learned and fine tuned on another publicly available CXR dataset and evaluated to be 85.26% accurate for 20 epochs.

Performance Optimization of Solar Powered Pump for Irrigation in Tanjung Raja, Indonesia

Abstract: Agriculture is one of the industries that can benefit greatly from solar energy. Most Indonesians still rely on agriculture for a living, including farmers in Muara Enim Regency, South Sumatra Province, who harvest their rainfed rice fields only 1–2 times per year. More water for irrigation, not just during the rainy season, can be used to extend harvest time, and this condition is possible if a solar-powered irrigation pump is used. This study attempts to develop a solar light tracking system to increase irradiance and produce more electricity in order to improve the performance of a solar power plant. This paper looks into the possibility of improving the Tanjung Raja Solar Power Plant. The experimental results show that the maximum power produced by a dynamic PV panel is 24.78% greater than that of a static PV panel with a water debit pump, which is 10.24% greater. Dynamic solar panels have a higher efficiency than static solar panels. However, a more in-depth economic analysis is required to validate that the dynamic PV system is more economically effective when considering how much paddy is harvested using both methods.