Experimental investigation of drying of garlic clove in solar dryer using phase change material as energy storage

This investigation deals with thermodynamic analysis, which offers an alternative approach to evaluate the performance of solar dryers and thin-layer drying characteristics of garlic cloves in a developed system. The garlic cloves were dried from a moisture content of 55.5 % (w.b.) to 6.5 % (w.b.) for 8 h. The drying data obtained were fitted to five different drying kinetics models. Of these, the model suggested by Midilli et al. [28] had the best fit with the drying behavior of garlic cloves. The energy efficiency without and with recirculation of the air exiting the drying chamber during the study varied from 43.06 to 83.73 %, and 3.98 to 14.95 %, respectively, while the exergy efficiency corresponding to the energy efficiency of the drying process ranged from 5.01 to 55.30 % and 67.06 to 88.24 %, respectively.     

Kinetics and thermoluminescence glow curve study of Ba2MgSi2O7:Eu3+, Dy3+

This paper reports thermoluminescence glow curves of Eu³⁺, Dy³⁺-doped Ba₂MgSi₂O₇ phosphor for different UV exposure times. Kinetic data were evaluated by the peak-shape method. The glow curves shift toward higher intensity with increasing exposure time to UV at 365 nm. When the heating rate was 5 °C s^?1, peaks were observed at 101.76, 109.69, 102.67, and 104.05 °C, respectively, after UV exposure for 5, 10, 15, and 20 min. The glow peaks are indicative of second-order kinetics. Different kinetic data, i.e. trap depth, order of kinetics, activation energy, and frequency factor were also calculated. To evaluate the persistence characteristics of the luminescence of the phosphor, the lifetime of the charge in the trap was calculated; it was 348, 660, 368, and 428 s for UV exposure of 5, 10, 15, and 20 min, which indicates the luminescence of the phosphor is persistent.     

N-donor stabilized complexes of nickel(II) diphenyldithiophosphates: single-crystal X-ray,HSA and computational analysis

Transition Metal Chemistry - Nickel(II) complexes with octahedral coordination stabilized by N-donor ligands corresponds to [{(ArO)2PS2}2Ni·L2] [Ar = 4-(C2H5)C6H4 (3), and...     

Resilient and agile engineering solutions to address societal challenges such as coronavirus pandemic

The world is witnessing tumultuous times as major economic powers including the US, UK, Russia, India, and most of Europe continue to be in a state of lockdown. The worst-hit sectors due to this lockdown are sales, production (manufacturing), transport (aerospace and automotive) and tourism. Lockdowns became necessary as a preventive measure to avoid the spread of the contagious and infectious “Coronavirus Disease 2019” (COVID-19). This newly identified disease is caused by a new strain of the virus being referred to as Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS CoV-2; formerly called 2019-nCoV). We review the current medical and manufacturing response to COVID-19, including advances in instrumentation, sensing, use of lasers, fumigation chambers and development of novel tools such as lab-on-the-chip using combinatorial additive and subtractive manufacturing techniques and use of molecular modelling and molecular docking in drug and vaccine discovery. We also offer perspectives on future considerations on climate change, outsourced versus indigenous manufacturing, automation, and antimicrobial resistance. Overall, this paper attempts to identify key areas where manufacturing can be employed to address societal challenges such as COVID-19.     

Lossy mode resonance-based uniform core tapered fiber optic sensor for sensitivity enhancement

A lossy mode resonance (LMR)-supported fiber optic sensor in which a uniform fiber core is placed among two identical tapered regions, is investigated numerically. Indium tin oxide (ITO) and aluminum-doped zinc oxide (AZO) are considered as LMR active materials used to excite several lossy modes and gold and silver are used as surface plasmon resonance (SPR) active materials. In this probe design, a central uniform core coated with ITO/AZO is the active sensing region, whereas tapered regions are meant for bringing the incident angle close to the critical angle. The sensitivity of the present fiber optic bio-sensor is evaluated for first two LMRs utilizing both ITO and AZO separately, along with its variation with the taper ratio (TR). For ITO, the maximum sensitivity values are observed to be 18.425 μm RIU⁻¹ (refractive index unit) and 0.825 μm RIU⁻¹, corresponding to the first and second LMRs, respectively, at a TR of 1.6 and for AZO, equivalent values are 0.79 μm RIU⁻¹ and 0.35 μm RIU⁻¹, respectively, at a TR of 2.0. The results illustrate that the first LMR is more sensitive than the second LMR and the ITO-coated probe possesses greater sensitivity than the AZO-coated probe for both LMRs. Similarly, for the fiber optic SPR sensor, the maximum value of sensitivity is 5.6425 μm RIU⁻¹, in the case of gold and 5.0615 μm RIU⁻¹ in the case of silver, at a TR of 1.6. Hence, the result shows that the sensor with the present fiber optic probe design has around a 3-fold enhancement in sensitivity compared with conventional SPR sensors. This study will have applications in many sensing schemes where the requirement of large sensitivity is vital.     

Selenadiazolopyridine: a synthon for supramolecular assembly and complexes with metallophilic interactions

The synthesis and characterization of the complexes of Cu(I), Ag(I), Cu(II), and Co(II) ions with 1,2,5-selenadiazolopyridine (psd) is reported. The following complexes have been prepared: [Cu(2)(psd)(3)(CH(3)CN)(2)](2+)2(PF(6)(-)); [(CuCl)(2)(psd)(3)]; [Cu(2)(psd)(6)](2+)2(ClO(4))(-); [Ag(2)(psd)(2)](2+)2(NO(3))(-); [Ag(2)(psd)(2)](2+)2(CF(3)COO)(-); [Cu(psd)(2)(H(2)O)(3)](2+)2(ClO(4))(-)·(psd)(2); [Cu(psd)(4)(H(2)O)](2+)2(ClO(4))(-)·(CHCl(3)); [Cu(psd)(2)(H(2)O)(3)](2+)2(NO(3))(-)·(H(2)O)·(psd)(2), and [Co(psd)(2)(H(2)O)(4)](2+)2(ClO(4))(-)·(psd)(2). The electronic structure of ligand psd, in particular the bond order of Se-N bonds, has been probed by X-ray diffraction, (77)Se NMR, and computational studies. A detailed analysis of the crystal structures of the ligand and the complexes revealed interesting supramolecular assembly. The assembly was further facilitated by the presence of neutral ligands for some complexes (Cu(II) and Co(II)). The molecular structure of the ligand showed that it was present as a dimer in the solid state where the monomers were linked by strong secondary bonding Se···N interactions. The crystal structures of Cu(I) and Ag(I) complexes revealed the dinuclear nature with characteristic metallophilic interactions [M···M] (M = Cu, Ag), while the Cu(II) and Co(II) complexes were mononuclear. The presence of M···M interactions has been further probed by Atoms in Molecules (AIM) calculations. The paramagnetic Cu(II) and Co(II) complexes have been characterized by UV-vis, ESI spectroscopy, and room temperature magnetic measurements.     

Miceller-Mediated Phosphomolybdic Acid: Highly Effective Reusable Catalyst for Synthesis of Quinoline and Its Derivatives

A simple, efficient, and ecofriendly procedure has been developed for the synthesis of quinoline and its derivatives in a one-pot reaction of aniline with crotonaldehyde or methyl vinyl ketone using phosphomolybdic acid as solid acid catalyst in miceller media. The catalyst was easily recycled and reused.     

A novel method for bromodecarboxylation of α,β-unsaturated carboxylic acids using catalytic sodium nitrite

A first novel synthetic utility of catalytic sodium nitrite in combination with aqueous HBr, for bromo decarboxylation of α,β-unsaturated carboxylic acid is described. α,β-Unsaturated carboxylic acid compounds successfully converted into corresponding bromo compounds. The advantages of this protocol are shorter reaction time and moderate to good yields.     

Formation of diaryl(allyl)phosphine in π -allyl palladium(II) induced cleavage of triarylphosphines

A reverse migration of allylic group from palladium to phosphorus and the formation of diaryl(allyl)phosphine in the π -allyl palladium(II) induced cleavage of triarylphosphines has been demonstrated.