Improved controller design for two-input-two-output (TITO) unstable processes

Controller design for unstable processes is relatively difficult when compared to stable processes. The complexity increases further for multivariable unstable processes. In this work, simplified tuning rules are proposed to design PID controller for unstable multivariable processes. Decouplers are applied to make the loops independent and diagonal elements of equivalent transfer function are used to design controllers. For this, the decoupler design procedure proposed by Hazarika and Chidambaram [10] is used. Two theoretical examples of TITO unstable processes with time delays are considered for simulation. Comparative analysis has been carried out with the recently reported methods in the literature and observed that the proposed method provides improved closed loop performances. Robustness studies are also carried out with various perturbations in the processes

Studies on the Effects of Bioprocess Parameters and Kinetics of Rhamnolipid Production by P. aeruginosa NITT 6L

Biosurfactants are gaining popularity in recent times due to lower toxicity, biodegradability, environmental compatibility and activity in extreme conditions. An air isolate was isolated previously for biosurfactant production in our laboratory, and characterized and named as P. aeruginosa NITT 6L. The biosurfactant thus produced was characterized to be surface-active rhamnolipid. This paper presents the study of the influence of various bioprocess parameters such as agitation, aeration and inoculum volume on rhamnolipid production by the isolate. Kinetics of rhamnolipid production in optimized media and process conditions were investigated. The rhamnolipid production was found to be increased after nitrogen depletion during stationary phase. The maximum rhamnolipid concentration of about 7.65 g L–1 was achieved after 96 h. Logistic model was found to be satisfactory in fitting the microbial growth. Emulsification activity of the crude rhamnolipid extract with different hydrocarbons was studied. The crude extract of rhamnolipid reduced the surface tension of water from 71.4 to 27.5 mN m–1, and CMC was about 11 mg L–1. Also, the usefulness of the extracted rhamnolipid produced under optimal conditions was investigated for remediation of crude oil contaminated soil. Soil washing with 0.3 % rhamnolipid removed about 71 % of crude oil present in sand samples within 24 h

Effect of Tris and Biociphos-Plus Extenders on the Extracellular Enzyme Release of Phosphatases and Transferases in Punganur Bull Semen

The present investigation was carried out to study phosphatase and transferase enzymes leakage in the neat and extended Punganur bull semen before and after freezing with Tris and Biociphos-plus extenders. Among the bulls studied, the Alkaline Phosphatase (AKP) concentration in fresh semen was significantly different but Acid Phosphatase (ACP) was not significantly different and a positive correlation between the concentration of AKP and semen volume, individual motility, sperm concentration and total abnormalities were observed. Aspartate aminotransferase (AST) and Alanine aminotransferase (ALT) concentrations were not significantly different and positively correlated with individual motility, sperm concentration, percentage of live sperms and acrosomal damage. Leakage of AKP, ACP, AST and ALT enzymes before freezing the semen of Punganur bulls was observed to be significantly higher in the semen extended with Biociphos-plus extender

Bacillus cereus KLUVAA Mediated Biocement Production Using Hard Water and Urea

In the present study, a potential bacterial strain with maximum urease activity was isolated from urea-rich paddy field soil for biocement production. The bacterial isolate was screened using Christensen selective agar media and named as KLUVAA. This isolate was found to be tolerant up to 10 % urea. 16S rRNA sequencing analysis identified the isolate KLUVAA as Bacillus cereus. Biocement production was carried out using tap water with 431.7 mg L–1 of hardness as a natural source of calcium. Functional groups present in biocement were analysed using FT-IR spectrum. The morphology and elemental composition of the biocement was studied using SEM with EDS mapping and XRD analyses. Thermogravimetric analysis was used to study the thermal stability of the microbial biocement. Further, process parameters were optimized for enhancing the yield of biocement. This work is licensed under a Creative Commons Attribution 4.0 International License

A comparative study of fractional order PIλ /PIλ Dμ tuning rules for stable first order plus time delay processes

Conventional PID tuning methods may not be sufficient to deal with complex processes of modern industry. For better control, fractional order PIλDµ controller was introduced as the generalization of classical PID controller with the help of non-integer order (fractional order) calculus. The fractional calculus uses integration and differentiation with a fractional order or complex order. The major advantage of fractional derivative is the ability to inherit the nature of the processes. In general, the control loop includes both fractional order process model and fractional order controller. However, the processes to be controlled are usually modeled as integer order models and controlled using fractional order controllers. But if the plant model is obtained as fractional model, it is converted into integer order model by approximating the fractional terms using different approximations proposed in the literature. With all the above mentioned advantages, several fractional order PIλ/PIλDµ tuning rules are proposed in the literature for integer order systems and researchers are still proposing the new rules. The main aim of this paper is to compare fractional order PI/PID tuning methods based on Integral of Absolute Error (IAE), Total Variation (TV) and Maximum Sensitivity (Ms). The main reason for choosing fractional order PIλ/PIλDµ controllers is their additional degrees of freedom that result in better control performance. These tuning rules were applied on several first order plus time delay processes subjected to step change in setpoint and disturbance

A VOS analysis of LSTM Learners Classification for Recommendation System

In response to the growing popularity of social web apps, much research has gone into analyzing and developing an AI-based responsive suggestion system. Machine learning and neural networks come in many forms that help online students choose the best texts for their studies. However, when training recommendation models to deal with massive amounts of data, traditional machine learning approaches require additional training models. As a result, they are deemed inappropriate for the personalized recommender generation of learning systems. In this paper, we examine LSTM-based strategies in order to make useful recommendations for future research

Major and minor fisheries harbours of India. 7. The fisheries harbours and fishery along the north Tamilnadu and south Andhra Pradesh coasts

There are four functional fisheries harbours in the north Tamil Nadu-south Andhra Pradesh coast, viz., Chennai (major), Nizampatnam, Cuddalore and Pazhayar (minor). A medium harbour in Pondicherry is under construction. There is a temporary jetty in Krishnapatnam and a fish landing platform in Pulicat

The fishery, biology and stock assessment of jew fish resources of India

Sciaenids are one of the major component of the demersal trawl The total catch of this resource during 1990-94 period was 1.50,142 t contributing 8.86% to the demersal catch of India. A number of species are found in different states of India. Of which biological and stock assessment studies were made on eleven important species. Crustaceans and fish appear to be the chief food in Juvenile and adult stage respectively. Most of the species have a protracted spawning season. Among all the species studied the largest asymptotic length was estimated for O.ruber from Tuticorin and the smallest for J. sina from Cochin. The highest Z of 7.59 was recorded for K. axillaris from Chennai and the lowest was for O. cuvierifrom Mumbai. The average exploitation rate (E) and the Lc/ Lao was 0.62 and 0.53 respectively. The present yield is 91.222 t and the MSY is 1.42,613 t for all the species taken together. The exploitation rate for almost all the stocks in the states appears to be more than the optimum leve

Dual substrate fermentation using palm oil and glucose for production of eco-friendly biosurfactants using <em>P. aeruginosa</em> NITT 6L

101-105Studies have been conducted to improve biosurfactant (rhamnolipid) production from Pseudomonas aeruginosa NITT 6L in liquid state fermentation utilizing palm oil and glucose as substrates. The pH and minimal salt media (MSM) compositions such as KH2PO4, K2HPO4, NaNO3, MgSO4, NaCl and FeSO4 are optimized using design of experiments. One-factor-at-a-time optimization is employed to evaluate the effects of palm oil and its co-substrate glucose on biosurfactant production. The optimal levels of the aforementioned variables are (g/L) glucose 30.0, KH2PO4 2.0, K2HPO4 5.0, NaNO3 3.5, FeSO4 0.003, MgSO4 0.2, with palm oil concentration of 1.5% (v/v). The fermentation conditions viz. period of fermentation, agitation rate, aeration and concentration of inoculum are optimized by carrying out separate experimentations. The optimum period of fermentation, agitation rate, aeration and concentration of inoculum in the fermentation medium  are found to be 7 days, 150 rpm, 60% and 2% (v/v), respectively, for  maximum rhamnolipid production of about 3.73 g/RE l