Model Based Controller and Linear Cascade Controller Applied to Fed Batch pH Process

Abstract

The present study aims at bringing out the best features of model‐based control, linear cascade control when applied to highly non‐linear systems like pH‐controlled fed‐batch processes. For these processes, control of pH by conventional Proportional‐Integral‐Derivative controller fails to provide satisfactory performance, because of the extreme non‐linearity in the pH dynamics. In the present study, for a fed‐batch neutralization process, a non‐linear control law has been derived for the model‐based Proportional Integral controller. Typical problems in process control like sampling, delay and perturbations in model parameters are addressed in this study using model‐based control. The simulation results show the superior performance and robustness of the model‐based controller and linear cascade controller over that of the conventional Proportional Integral controller.     

Experimental investigations on the SiO<Subscript>2</Subscript> flux-assisted GTA welding of super-austenitic stainless steels

Analyzed in this paper are barrier properties of wood specimens treated by ball burnishing. For the purpose of experimental investigation, special device was designed which allows continuous monitoring of the volume of water absorbed by specimen within particular time intervals. The device allows water pressurized at 3 bar to efficiently penetrate specimen internal structure over its burnished/non-burnished surface interface. The experimental investigation encompassed six types of wood—beech, acacia, walnut, oak, linden, and ash tree. Comparative analysis was performed to establish relative resistance to water penetration in burnished and non-burnished specimens, as well as the quantities of water volume absorbed over time. The results indicate that ball burnishing is capable of enhancing barrier properties in all of the examined types of wood.     

A Proxy Signature Based Efficient and Robust Handover AKA Protocol for LTE/LTE-A Networks

Wireless Personal Communications - An efficient and robust handover is one of the essential requirements of several applications in LTE/LTE-A network. These applications are reliable only after a...     

Potential of biohydrogen generation using the delignified lignocellulosic biomass by a newly identified thermostable laccase from Trichoderma asperellum strain BPLMBT1

Delignification of plant-based biomass is one of the most important steps to determine the commercial success of bioavailability, and enzymatic delignification mediated via laccases could significantly improve the yield in an eco-friendly and precise manner. In this study, an extracellular laccase is newly identified and characterized from Trichoderma asperellum strain BPLMBT1. The purified laccase with specific activity of 51.0 U/mg, possesses a molecular mass of 65.0 kDa with absorbance peaks of 610–630 and 330 nm in the UV–Vis spectrum indicating the presence of the inclusive types I and III copper catalytic centers. The wide thermal and pH stability of this laccase, with optimal temperature of 80 °C and 3.0, are demonstrated by biochemical characterization and kinetics determination. In addition, the delignification of sweet sorghum stover biomass by the purified laccase resulting in an optimal lignin removal of 76.93% reveals its potential of utilizing delignified biomass for biohydrogen production 402.01 mL of biohydrogen was achieved after 84 h of anaerobic fermentation, which is 3.26-fold higher than the control without enzymatic pretreatment. The overall outcomes demonstrate an efficient way to utilize the thermostable laccase for biofuels conversion from lignocellulosic biomass.     

Power and area-optimised Carry-Select Adder architecture for standard cell-based design

A Carry-Select Adder (CSA) is one of the most suitable adders for high-speed applications, but the power and area penalties are greater, because it requires a double Ripple-Carry Adder (RCA) structure corresponding to carry inputs 0 and 1. Current low-power and low-area techniques are not suitable for a standard cell-based design which is one of the widely adopted design methodologies. Our work proposes two simple optimised architectures suitable for standard cell-based designs. A simple decision logic that replaces the RCA for Carry input 1 in a conventional CSA is proposed. One of the proposed architectures reduces power and area significantly with a small delay penalty compared to the existing techniques. Another proposed architecture improves the speed of operation and reduces the power and area considerably. The first one is more suitable for high-speed arithmetic in battery-operated applications where there is a trade-off between speed and power, while the other one is suitable for high-performance applications which also require area and power optimisation. The proposed architectures were implemented in TSMC 0.18um CMOS technology, and compared with conventional Square Root Carry-Select Adders and an existing standard cell-based design.     

Investigation on the nucleation kinetics of antiferroelectric ADP admixtured ferroelectric TGS crystals

Induction period and interfacial energy have been determined for the aqueous solution growth of ammonium dihydrogen orthophosphate admixtured triglycine sulphate. It is observed that the induction period decreases exponentially with supersaturation and hence the nucleation rate increases with the increase of supersaturation. The solubility of synthesized ADPTGS has been estimated at different temperatures. ADPTGS has a positive temperature coefficient of solubility. Nucleation parameters such as radius of the critical nucleus, number of molecules in the critical nucleus and critical free energy change have also been investigated.     

Tunable shapes in supported metal nanoparticles: From nanoflowers to nanocubes

The facile preparation of a range of supported nanoparticles on porous materials was successfully accomplished through the use of a range of environmentally friendly protocols including a modified impregnation/reduction methodology, ultrasounds and microwave irradiation. Materials were characterised by transmission electron microscopy (TEM) and XPS. Different morphologies including conventional nanospheres, nanoflower aggregates, nanorod-like structures and nanocubes were achieved under different conditions. The reported supported nanoparticles are envisaged to have interesting applications in various areas including catalysis, optics and sensors.     

Sintered Fe08%C10%Si04%Cu P/M Steel Preform Behaviour During Cold Upsetting

Cold upsetting experiments were carried out on sintered Fe 0.8%C1.0%Si-0. 4%Cu steel preforms in order to evaluate their deformation characteristics. Powder preforms of 86 % of theoretical density, with two different ratios of height to diameter, were prepared using a suitable die set assembly on a 1.0 MN capacity hydraulic testing machine. Sintering was carried out in an electric muffle furnace for 1.5 h at 1 150 ℃. Each sintered compact was subjected to incremental loading of 0.04 MN under dry friction condition till a crack appeared at the free surfaces. The experimental results were critically analysed, the stress as a function of strain and densification was obtained, then the work hardening behaviour was analyzed. It has been found that in the process of enhancing densification, strength and strain hardening is also induced during upsetting, but the work hardening behaviour is not homogenously enhanced against strain and densification.     

An optical tool for quantitative assessment of phycocyanin pigment concentration in cyanobacterial blooms within inland and marine environments

Quantitative assessment of the pigment phycocyanin (PC) in cyanobacterial blooms is essential to assess their abundance and distribution and consequently aid their management in many recreational waters within inland and coastal environments. In contrast to the open-ocean waters, these water bodies are very complex with a pronounced heterogeneity of their optical properties, and hence accurate retrieval of the water-leaving radiances and PC concentration from satellite observations is notoriously difficult with existing algorithms. In the present study, a new inversion algorithm is developed as a rapid cyanobacteria bloom assessment method and its retrievals of PC are compared with in-situ and satellite observations and those from a previously reported inversion algorithm. The new algorithm estimates PC concentration on the basis of the unique absorption feature of phycocyanin at 620 nm which is isolated from the total pigment absorption by taking advantage of the well-recognized absorption and reflectance features in the red and near-infrared (NIR) wavelengths (less impacted by the influences of the overlapping absorption signatures of the mixture constituents and pigment packaging). The by-products of this work include chl-a concentration and predictions from reflectance data to monitor the cyanobacterial component and non-cyanobacterial component of the phytoplankton assemblage and to evaluate PC:Chl-a pigment weight ratios for specific water types. Initial validation of the algorithm was performed using in-situ field data in turbid productive waters dominated by phycocyanin and other pigments, yielding coefficients of determination and slope close to unity and mean errors less than a few percent. These results suggest that the algorithm could be used as a rapid assessment tool for the remote-sensing assessment of the spatial distribution and relative abundance of cyanobacterial blooms in many regional water bodies.