Antiandrogen and Antimicrobial Aspects of Coordination Compounds of Palladium(II), Platinum(II) and Lead(II)

Synthesis, characterization and antimicrobial activities of an interesting class of biologically potent macrocyclic complexes have been carried out. All the complexes have been evaluated for their antimicrobial effects on different species of pathogenic fungi and bacteria. The testicular sperm density, testicular sperm morphology, sperm motility, density of cauda epididymal spermatozoa and fertility in mating trails and biochemical parameters of reproductive organs have been examined and discussed. The resulting biologically active [M(MaL(n))(R(2))]Cl(2) and [Pb(MaL(n))(R(2))X(2)] (where, M = Pd(II) or Pt(II) and X = Cl or NO(3)) type of complexes have been synthesized by the reactions of macrocyclic ligands (MaL(n)) with metal salts and different diamines in 1:1:1 molar ratio in methanol. Initially the complexes were characterized by elemental analyses, molecular weight determinations and conductivity measurements. The mode of bonding was established on the basis of IR, (1)H NMR, (13)C NMR, (195)Pt NMR, (207)Pb NMR, XRD and electronic spectral studies. The macrocyclic ligand coordinates through the four azomethine nitrogen atoms which are bridged by benzil moieties. IR spectra suggest that the pyridine nitrogen is not coordinating. The palladium and platinum complexes exhibit tetracoordinated square-planar geometry, whereas a hexacoordinated octahedral geometry is suggested for lead complexes.     

Arbitrary shaped ice particle melting under the influence of natural convection

This work is devoted to numerical simulations of an arbitrary shaped ice particle melting inside water under the influence of natural convection. Specifically, four different shapes of the ice particle have been studied: sphere, cylinder, cross shaped cylinder, and irregular sphere with radial bumps on its surface. A 2D axisymmetric particle‐resolved numerical model has been employed on a fixed grid to study the detailed melting dynamics of an ice particle. The solid‐liquid interface is treated as a porous medium characterized by the permeability coefficient which is used to damp the velocity values inside the interface. The model results have been compared with an existing experimental results produced by A. Shukla et al. (Metal Mater Trans B. 2011; 42(1):224–235). Very good agreement between our predictions and experimental data have been achieved. Based on the analysis of numerical simulation results, melting process is found to advance through two distinct regimes, namely, establishment of the natural convection and active melting of ice particle exhibiting substantial amount of fluid‐particle interactions. A set of dimensionless parameters have been identified to distinguish between regimes. Finally, we developed a semi‐empirical to predict the melting of any arbitrary shaped ice particle and validated it against the particle‐resolved numerical simulation and experimental results. The comparison showed good agreement. Finally, the presented semi‐empirical model can be used as sub‐grid model in Euler‐Lagrange based numerical models to study the phase change phenomena in particulate flow systems. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3158–3176, 2017     

Rapid Quantification of Low-Viscosity Acetyl-Triacylglycerols Using Electrospray Ionization Mass Spectrometry

Acetyl‐triacylglycerols (acetyl‐TAG) possess an sn‐3 acetate group, which confers useful chemical and physical properties to these unusual triacylglycerols (TAG). Current methods for quantification of acetyl‐TAG are time consuming and do not provide any information on the molecular species profile. Electrospray ionization mass spectrometry (ESI–MS)‐based methods can overcome these drawbacks. However, the ESI–MS signal intensity for TAG depends on the aliphatic chain length and unsaturation index of the molecule. Therefore response factors for different molecular species need to be determined before any quantification. The effects of the chain length and the number of double‐bonds of the sn‐1/2 acyl groups on the signal intensity for the neutral loss of short chain length sn‐3 groups were quantified using a series of synthesized sn‐3 specific structured TAG. The signal intensity for the neutral loss of the sn‐3 acyl group was found to negatively correlated with the aliphatic chain length and unsaturation index of the sn‐1/2 acyl groups. The signal intensity of the neutral loss of the sn‐3 acyl group was also negatively correlated with the size of that chain. Further, the position of the group undergoing neutral loss was also important, with the signal from an sn‐2 acyl group much lower than that from one located at sn‐3. Response factors obtained from these analyses were used to develop a method for the absolute quantification of acetyl‐TAG. The increased sensitivity of this ESI–MS‐based approach allowed successful quantification of acetyl‐TAG in various biological settings, including the products of in vitro enzyme activity assays.     

Performance of plate heat exchangers during calcium sulphate fouling — investigation with an in-line filter

The uncertainty about the fouling behaviour is one of the main reasons why plate and frame heat exchangers are not more widely installed in the chemical process industry and in power generating facilities. In the present investigation, the deposition of calcium sulphate in two different plate heat exchanger geometries was investigated. The deposition process was deliberately focused on crystallisation fouling through the installation of an in-line filter and the mode of preparation of the test solution. The investigated operating parameters were solution concentration, flow velocity, and bulk and surface temperatures. The heat exchangers were opened after each experiment to record the appearance and distribution of the deposits. The key result of this investigation is the strong correlation between the plate design and the tendency for deposit formation.     

Transport of lithium through a supported liquid membrane of LIX54 and TOPO in kerosene

A mathematical transport model is developed for the extraction of lithium from dilute synthetic solution, simulating geothermal water, using a supported liquid membrane (SLM) of LIX54 (major component is -acetyl-m-dodecylacetophenone) and TOPO (tri-n-octylphosphine oxide) in kerosene. The model is based on fundamental mass transfer and kinetics mechanisms that account for all possible transport resistances. The model is solved numerically and is used to investigate the effect of various extraction conditions and membrane support characteristics. Reasonable agreement is found between the predicted and the experimental results reported in literature.     

Predictions for fatigue crack growth life of cracked pipes and pipe welds using RMS SIF approach and experimental validation

The objective of the present study is to understand the fatigue crack growth behavior in austenitic stainless steel pipes and pipe welds by carrying out analysis/predictions and experiments. The Paris law has been used for the prediction of fatigue crack growth life. To carry out the analysis, Paris constants have been determined for pipe (base) and pipe weld materials by using Compact Tension (CT) specimens machined from the actual pipe/pipe weld. Analyses have been carried out to predict the fatigue crack growth life of the austenitic stainless steel pipes/pipes welds having part through cracks on the outer surface. In the analyses, Stress Intensity Factors (K) have been evaluated through two different schemes. The first scheme considers the ‘K’ evaluations at two points of the crack front i.e. maximum crack depth and crack tip at the outer surface. The second scheme accounts for the area averaged root mean square stress intensity factor (K_RMS) at deepest and surface points. Crack growth and the crack shape with loading cycles have been evaluated. In order to validate the analytical procedure/results, experiments have been carried out on full scale pipe and pipe welds with part through circumferential crack. Fatigue crack growth life evaluated using both schemes have been compared with experimental results. Use of stress intensity factor (K_RMS) evaluated using second scheme gives better fatigue crack growth life prediction compared to that of first scheme. Fatigue crack growth in pipe weld (Gas Tungsten Arc Welding) can be predicted well using Paris constants of base material but prediction is non-conservative for pipe weld (Shielded Metal Arc Welding). Further, predictions using fatigue crack growth rate curve of ASME produces conservative results for pipe and GTAW pipe welds and comparable results for SMAW pipe welds.     

Comparison of the periodic solution method with TRNSYS and SUNCODE for thermal building simulation

Based on periodic solutions of the governing heat conduction equations in a single zone building, computer software ADMIT has been developed for thermal simulation of buildings. Standard computer software, namely TRNSYS and SUNCODE, have also been used to simulate the same building under similar conditions. Simulations have been performed for three different climatic zones in India for light and heavy constructions under conditions of glazed/unglazed areas and ventilation rates. The results are presented in terms of the hourly variation of the room temperature. For insulated heavy construction, the results of different models are significantly different. This difference is due to the use of different approaches to solve the heat conduction equations. SUNCODE depends on the RC network approach and underestimates the heat losses. TRNSYS uses the transfer function approach, which is sensitive to the initially assumed value of the room temperature. ADMIT represents a quasi-steady-state periodic variation and is not suitable for transient variations. For insulated light buildings, the heat transfer mechanisms used in the mathematical models are not the governing factors. The models also differ in treating the penetration of solar radiation through a glazed window and the subsequent heat-transfer mechanism. For a south window and air changes in an insulated building, the results obtained by SUNCODE and ADMIT are in good agreement, but the results obtained by TRNSYS are considerably different. The reason for this needs detailed analysis.     

LoCaL: Link-optimized cone-assisted location routing in flying ad hoc networks

Recently, flying ad hoc networks (FANETs) has become a core research area in wireless networks that involves multiple unmanned aerial vehicles (UAVs). It is widely used in modern warfare for surveillance, monitoring and reconnaissance. The routing in FANETs poses a more significant challenge due to limited energy and frequent link disconnection between the UAVs. Consequently, an effective route is always required to ensure data transmission between UAVs. Therefore, this research proposes a link-optimized cone-assisted location (LoCaL) routing protocol for FANETs. The main goal of the proposed LoCaL is to enhance the link duration between the UAVs in which a source selects a forwarding UAV from a given set of neighbours by estimating the residual energy, link duration time and safety degree parameters. Proposed LoCaL provides better stability and less frequent route breaks between source and destination. Further, the mathematical formulation of the proposed approach is presented through the utility function to enhance the route stability by selecting all those relay UAVs in the cone-shaped request zone, which reduces the routing overhead in discovering the route. Finally, the performance of the LoCaL has been presented through key indicators such as energy consumption, routing overhead, message delivery ratio, network lifetime and delay compared to the existing approaches.     

Design of energy-efficient precoders in MIMO cognitive two-way relay network

This paper addresses the energy efficiency (EE) maximization problem for a multi-input multi-output cognitive two-way relay network. The secondary system, comprises of a two-way amplify-and-forward (AF) relay and two transceivers, co-exists with the licensed primary user (PU). The secondary transceivers communicate through the two-way AF relay. We jointly design the precoders for the secondary transceivers and the AF relay with the aim to maximize the EE while satisfying the transmit power constraints at the secondary transceivers and the relay, quality-of-service constraints at the secondary transceivers, and interference constraints at the PU. The resulting maximization problem is a non-convex fractional programming problem with three unknown precoder matrices. This problem is first simplified and converted into a vector valued problem using singular value decomposition. Further, the tools of iterative optimization scheme and the fractional programming theory are employed to solve the simplified problem. The computational complexity and convergence behaviour of the proposed solution are analysed. Numerical results are presented to illustrate the effectiveness of the proposed design in terms of the achievable EE and the probability of feasibility.