Influence Of Essential Parameters Research Articles

Lactic acid production from cashew apple bagasse, an agro-industrial waste, and its application in the enzymatic synthesis of polylactic acid

The use of cashew apple bagasse hemicellulose hydrolysate (CABH) to produce lactic acid by two strains of lactic acid bacteria, Lactobacillus plantarum FJ05311 and L. plantarum FJ05315, was evaluated. The application of cashew apple bagasse (CAB) would enhance the establishment of a biorefinery from this agro-industrial residue since its main compounds, cellulose, hemicellulose, and lignin, can be used to obtain several bioproducts. The influence of essential parameters was studied for the production of LA. The CABH contained mainly glucose and xylose at concentrations of approximately 40 g/L and 20 g/L, respectively. The process conducted at 30 °C, 100 rpm, and using the culture in the final of the growth phase (inoculum time of 24 h for LAB07 and 20 h for LAB14) and urea as nitrogen source enhanced the LA production for both strains, LAB07 and LAB14, reaching 24.3 g/L. The produced LA was used to synthesize polylactic acid (PLA) for the enzymatic route using lipase B from Candida antarctica (CALB). Then, the production of PLA from cashew apple bagasse hydrolysate is a sustainable alternative to produce a biodegradable polymer with many industrial applications and obtaining personal protective equipment to use in the current and future pandemics.

Numerical investigations of activation energy on the peristaltic transport of Carreau nanofluid through a curved asymmetric channel

Nanometric particles with base liquids cause the production of nanofluids, which are distinguished by their outstanding thermally conductive fluid properties and the expansion of electrical and mechanical devices. Based on these considerations, we devised a study to investigate the effect of activation energy on the peristaltic motion of Carreau nanofluid inside a curved asymmetric channel under the influence of a magnetic field. The governing equations for the curved channel of non-Newtonian fluid flow are formulated. The nonlinear partial differential equations system has been reduced to ordinary differential equations by the assumptions of low Reynolds number and long wavelength approximations. The resulting nonlinear coupled differential equations are numerically solved directly using NDSolve (numerical differential equation solver) coding of computational mathematical software Mathematica, and velocity, temperature, concentration, and streamlines are plotted. With graphical demonstrations, the influence of essential parameters on velocity, temperature, concentration, and streamlines is explained in detail. The dimensionless temperature distribution grows as the activation energy parameter grows. In reality, the number of energetic particles (with energies equal to or greater than activation energy) increases, resulting in improved temperature distribution.

Continuous microflow visible-light photocatalytic N-formylation of piperidine and its kinetic study

N-formylation of amines, a class of synthetically important reactions, is typically conducted using metal catalysts that are relatively expensive or not readily available and usually needs harsh conditions to increase the reaction efficiency. Here, an efficient continuous microflow strategy was developed for the gas-liquid visible-light photocatalytic N-formylation of piperidine, which achieved a reaction yield of 82.97% and a selectivity of >99% at 12 min using cheap organic dye photocatalyst under mild reaction conditions. The influence of essential parameters, including light intensity, temperature and equivalents of the gas, additive and photocatalyst, on the reaction yield was systematically studied. Furthermore, kinetic investigations were conducted, exhibiting the dependence of reaction rate and equilibrium yield of N-formylpiperidine on light intensity, temperature and photocatalyst equivalent. The microflow photocatalytic approach established in this work, which realized a markedly higher space-time yield than the conventional batch method (37.9 vs. 0.212 mmol·h−1·L−1), paves the way for the continuous, green and efficient synthesis of N-formamides.

Self-centring damper with multi-energy-dissipation mechanisms: Insights and structural seismic demand perspective

An innovative self-centring damper equipped with shape memory alloy elements and wedge-shaped friction plates (i.e. SMA-VFSD) characterised by multiple energy-dissipation mechanisms was developed. First, the notion and rationale of the damper was illustrated. Then, an analytical model enabling quantification of the hysteretic behaviour of the proposed SMA-VFSD was derived. A numerical parametric study using validated modelling techniques was subsequently conducted. The good agreement between the hysteretic responses of numerical models and analytical predictions confirmed the promise of the proposition and the adequacy of the analytical design model. Resorting to the analytical model, sensitivity analyses covering a wider spectrum of design parameters were performed, and the influence of essential parameters on the hysteretic behaviour of the damper was examined. Finally, the constant-ductility-based non-linear spectral analyses of an equivalent single-degree-of-freedom (SDOF) system representing steel frames equipped with SMA-VFSDs were performed to quantify the structural seismic demand and examine the effectiveness of the damper in improving the structural seismic performance. Two conventional self-centring systems characterised by flag-shaped hysteretic features were also studied for comparison. The analysis results showed that the multiple energy-dissipation mechanisms of the SMA-VFSDs are beneficial in reducing the structural inelastic seismic demand, highlighting the potential of the damper towards performance advances in self-centring structures.

Hybrid steel staggered truss frame (SSTF): A probabilistic spectral energy modification coefficient surface model for damage-control evaluation and performance insights

This paper attempted to quantify the inelastic seismic demand of hybrid steel staggered truss frame (SSTF) showing damage-control behaviour by using a probabilistic seismic demand spectral surface model. The study was commenced by developing the idea of hybrid SSTF composed of high strength steel members and low yield point steel dampers. In order to evaluate the structural damage-control behaviour, inelastic spectral energy modification coefficient surfaces were developed based on the single-degree-of-freedom (SDOF) analogy with bilinear kinematic hysteretic law. According to the statistical characteristics of the analysis data pool, it was found that the spectral energy modification coefficient followed a positively skewed probabilistic distribution. The energy modification coefficient surfaces were appreciably affected by structural parameters and statistical features of earthquake motions. Then, empirical expressions of the energy modification coefficient surfaces considering the influence of essential parameters were established. Based on previous experimental data, the finite element modelling techniques for developing a hybrid SSTF were verified. Cyclic pushover analysis and nonlinear response history analysis (NLRHA) of a prototype structure revealed that the hybrid SSTF showed favourable damage-control behaviour by concentrating inelastic actions in low yield point steel dampers. The insignificant post-earthquake residual deformations were also characterised. The adequacy of the proposed spectral energy modification coefficient surface model for evaluating the damage-control behaviour of hybrid SSTF was confirmed by NLRHA of the prototype structure.

Thiol–ended polycaprolactone: Synthesis, preparation and use in Pb(II) and Cd(II) removal from water samples

In the present study, thiol–ended polycaprolactone (TPCL) was successfully prepared by “ring opening polymerization” using 2-3 dimercaptopropanol and caprolactone. The synthesized material was employed as a possible adsorbent for removal of Cd(II) and Pb(II) ions from water samples and the influence of essential parameters (pH of 5.0, adsorbent dosage of 10.0 mg and contact time of 30.0 min) on the adsorption process was studied. Different techniques (BET NMR, FTIR, zeta potential, TGA/DTG) were used to characterize physical and chemical properties of the polymer. Various isotherm and kinetic models were employed to understand plausible mechanisms involved in the adsorption. It is revealed that adsorption process fitted very well with the Langmuir isotherm and pseudo-second-order kinetic models for both of the ions. The adsorption capacity decreased slightly (< 10%), demonstrating the thiol–ended polycaprolactone performance even after four consecutive adsorption–desorption cycles. The spike recovery studies with real water samples yielded recoveries of over 90% which indicated the applicability of the method. As a result, thiol–ended polycaprolactone has been demonstrated to be effective sorbent for the removal of Cd(II) and Pb(II) ions from aqueous solution, indicating its potential relevance in water remediation.

Size reduction by means of low-speed rotary shears

Low-speed comminution machines (circumferential velocity <5 m/s) with shearing, cutting and tearing stresses have proven to be suitable for the comminution of scrap metal and waste of non-brittle behaviour. Although this type of equipment has found a widespread application, the processes taking place during the comminution are known only to a limited extent. Their clarification was the objective of systematic basic research. Thereby, it was necessary to indicate the influence of essential parameters (position and shape of the stator, axial clearance) regarding the comminution process.

Ammonolysis of waste 1,2,3-trichloropropane by liquid ammonia

The preparation of 2-chloroallyamine by ammonolysis of 1,2,3-trichloropropane using liquid ammonia, has been examined. The influence of essential parameters on the selectivity of this transformation to 2-chloroallylamine in relation to the 1,2,3-trichloropropane consumed, and to the conversion of 1,2,3-trichloropropane, have been described by regression equations in the form of a polynomial of the second order. Optimum values of temperature, reaction time and molar ratio NH3 to 1,2,3-trichloropropane have been determined. © 2000 Society of Chemical Industry