1. The document discusses optimal and suboptimal control strategies for anaerobic digesters. Disturbances like inhibitors or changes in substrate concentration can cause digesters to become imbalanced.
2. Applying optimal control theory, the dilution rate can be adjusted optimally to minimize costs during transient imbalances and restore the digester. However, the optimal solution is usually impractical due to its complexity.
3. A simpler suboptimal control law is preferable, relating the dilution rate to easily measurable quantities. The paper considers disturbances from inhibitors entering the feed and changes in substrate concentration, developing optimal and suboptimal control models for each case.
Phytochemical Studies on Linum Usitatissimum Seeds and the Nanoformulation of...Editor IJCATR
The phytochemical investigation of Linum usitatissimum, family Linaceae, resulted in the separation and
identification of a lignane, 8–5' neolignan 1 (dehydrodiconiferyl alcohol-4-β-D-glucoside), in addition to
identification of many compounds by the GC/MS technique. The antimicrobial activities of hexane, methylene
chloride and butanol fractions were comparable to ampicillin. The activities against E. coli were 29.2%, 37.5%,
and 66.7%, respectively; against S. aureus were 45.4%, 36.4% and 63.6%, respectively, and against C. albicans
were 26.9%, 46.1% and 73.1%, respectively. Antioxidant activity was assessed by ABTS method. It decreased
in the following order: ascorbic acid > butanol fraction > methylene chloride fraction > hexane fraction. The
cytotoxicity against HePG2 was found to be “moderate” for butanol and methylene chloride fractions, and
“weak” for the hexane fraction. The cytotoxicity against MCF-7 was found to be “strong” for butanol fraction,
and “weak” for both hexane and methylene chloride fractions. The lignane-rich subfraction, Lu 3d was
incorporated into pluronic nano-micelles using nanoprecipitation technique through a modified procedure.
The physicochemical characteristics of the developed Lu 3d-loaded nano-micelles such as particle size,
potential and morphology were determined using DLS and HR-TEM. The average diameters of the prepared
plain and Lu 3d-loaded pluronic nano-micelles were found to be 207 ± 12 and 225 ± 18 nm, respectively. The
encapsulation of Lu 3d into nano-sized particles has enhanced their aqueous dissolution and consequently
improved their bioavailability. Nanoformulation of Lu 3d led also to a stable colloidal dispersion with a strong
green color, indicating its homogenous distribution in the aqueous medium at a significantly higher
concentration than that obtained using other solvents.
Kinetic Model Development for Bioremediation of Petroleum Contaminated Soil U...inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Alteration in Protein Metabolic Profiles in Liver Tissue of Rats during Dimet...iosrjce
Dimethoate is the widely used organophosphorous insecticides in agriculture. The irrational use of
Dimethoate in Yemen play a crucial role in the occurrence of many diseases affecting plants, animals and man.
Dimethoate (DM) is used to kill mites and aphids among other insects and is applied on citrus, cotton, fruit,
olives, potatoes, tea, tobacco and vegetables. The aim of the present work was to study biochemical changes
that might occur in the liver of albino rats as a result of DM intoxication. In the present investigation the
animals were treated with 1/10th of LD50 of DM via oral gavage (34.5mg/kg body weight. The first group
animals were considered as control animals. Second group of animals were treated with Dimethoate via oral
gavage (34.5mg/kg body weight which is 1/10th of LD50) for 10 days, third and fourth groups of animals were
administered for 20 and 30 days with an interval of 48h respectively. The DM treated groups are AST and ALT
was selected in the present investigation showed an increment. The present findings indicate that chronic
exposure to DM has clear toxic effect on the liver of albino rats.
Phasins promote bacterial growth and PHA synthesis and affect the number, size, and distribution. Due to their amphiphilic nature, these proteins play an important structural function, forming an interphase between the hydrophobic content of PHA granules and the hydrophilic cytoplasm content. Phasins have been observed to affect both PHA accumulation and utilization. Apart from their role as granule structural proteins, phasins have a remarkable variety of additional functions which might play an active role in PHA-related stress protection and fitness enhancement. Due to their granule binding capacity and structural flexibility, several biotechnological applications have been developed using different phasins, increasing the interest in the study of these remarkable proteins.
Phytochemical Studies on Linum Usitatissimum Seeds and the Nanoformulation of...Editor IJCATR
The phytochemical investigation of Linum usitatissimum, family Linaceae, resulted in the separation and
identification of a lignane, 8–5' neolignan 1 (dehydrodiconiferyl alcohol-4-β-D-glucoside), in addition to
identification of many compounds by the GC/MS technique. The antimicrobial activities of hexane, methylene
chloride and butanol fractions were comparable to ampicillin. The activities against E. coli were 29.2%, 37.5%,
and 66.7%, respectively; against S. aureus were 45.4%, 36.4% and 63.6%, respectively, and against C. albicans
were 26.9%, 46.1% and 73.1%, respectively. Antioxidant activity was assessed by ABTS method. It decreased
in the following order: ascorbic acid > butanol fraction > methylene chloride fraction > hexane fraction. The
cytotoxicity against HePG2 was found to be “moderate” for butanol and methylene chloride fractions, and
“weak” for the hexane fraction. The cytotoxicity against MCF-7 was found to be “strong” for butanol fraction,
and “weak” for both hexane and methylene chloride fractions. The lignane-rich subfraction, Lu 3d was
incorporated into pluronic nano-micelles using nanoprecipitation technique through a modified procedure.
The physicochemical characteristics of the developed Lu 3d-loaded nano-micelles such as particle size,
potential and morphology were determined using DLS and HR-TEM. The average diameters of the prepared
plain and Lu 3d-loaded pluronic nano-micelles were found to be 207 ± 12 and 225 ± 18 nm, respectively. The
encapsulation of Lu 3d into nano-sized particles has enhanced their aqueous dissolution and consequently
improved their bioavailability. Nanoformulation of Lu 3d led also to a stable colloidal dispersion with a strong
green color, indicating its homogenous distribution in the aqueous medium at a significantly higher
concentration than that obtained using other solvents.
Kinetic Model Development for Bioremediation of Petroleum Contaminated Soil U...inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Alteration in Protein Metabolic Profiles in Liver Tissue of Rats during Dimet...iosrjce
Dimethoate is the widely used organophosphorous insecticides in agriculture. The irrational use of
Dimethoate in Yemen play a crucial role in the occurrence of many diseases affecting plants, animals and man.
Dimethoate (DM) is used to kill mites and aphids among other insects and is applied on citrus, cotton, fruit,
olives, potatoes, tea, tobacco and vegetables. The aim of the present work was to study biochemical changes
that might occur in the liver of albino rats as a result of DM intoxication. In the present investigation the
animals were treated with 1/10th of LD50 of DM via oral gavage (34.5mg/kg body weight. The first group
animals were considered as control animals. Second group of animals were treated with Dimethoate via oral
gavage (34.5mg/kg body weight which is 1/10th of LD50) for 10 days, third and fourth groups of animals were
administered for 20 and 30 days with an interval of 48h respectively. The DM treated groups are AST and ALT
was selected in the present investigation showed an increment. The present findings indicate that chronic
exposure to DM has clear toxic effect on the liver of albino rats.
Phasins promote bacterial growth and PHA synthesis and affect the number, size, and distribution. Due to their amphiphilic nature, these proteins play an important structural function, forming an interphase between the hydrophobic content of PHA granules and the hydrophilic cytoplasm content. Phasins have been observed to affect both PHA accumulation and utilization. Apart from their role as granule structural proteins, phasins have a remarkable variety of additional functions which might play an active role in PHA-related stress protection and fitness enhancement. Due to their granule binding capacity and structural flexibility, several biotechnological applications have been developed using different phasins, increasing the interest in the study of these remarkable proteins.
Loperamide (LOP) is an antidiarrheal agent that works by slowing gastrointestinal transit and reducing intestinal secretions. The aim of the study is to evaluate the effect of loperamide consumption for five days on the intestinal oxidative balance, as well as the putative protective effect of mallow leaves extract. Animals were divided into one normal control group and fi ve experimental groups. LOP, LOP + the different doses of the extract (100, 200, and 400 mg/ kg, b.w.), and LOP+ yohimbine (2 mg/ kg, b.w. p.i.), used as reference drug. Loperamide (3 mg/ kg, b.w. p.o) was administered twice a day, for 5 days. Treatment with mallow extract or yohimbine protected against the lipid peroxidation, antioxidant enzymes activity depletion, the fall in the thiol group and reduced glutathione level as well as jejunal free iron and H2O2 overload induced by loperamide intoxication. Thereby, Malva sylvestris aqueous extract (MSAE) attenuates the pathogenicity of loperamide.
Polymeric composite membranes for temperature and pH-responsive delivery of d...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
Nowadays hydrogels are one of the upcoming classes of polymer-based controlled-release drug delivery systems. Temperature and pH-responsive delivery systems have drawn much attention because some diseases reveal themselves by a change in temperature and/or pH. The objective of this work is to prepare and characterize composite membrane using responsive nanoparticles into a polymer matrix.
Materials and Methods:
These nanoparticles were made of the copolymer poly (N-isopropylacrylamide-co-methaçrylic acid) by an aqueous dispersion polymerization process and are responsible for dual sensitivity to temperature and pH. Morphology study with SEM, swelling behavior with Dynamic Light Scattering Technique, in vitro drug release behavior with side-by-side Diffusion Cells were also investigated in this paper. Doxorubicin hydrochloride was used as a model solute.
Results:
The study on the release of doxorubicin hydrochloride showed that the release rate was higher at pH 5 than pH 7.4, increased with the increase of temperature. Nevertheless, ionic strength only poses a minor direct effect at higher pH.
Conclusion:
Such system may be potentially used as a tumor-targeting doxorubicin hydrochloride delivery in the body.
Hepatoprotective and antioxidant effects of Azolla microphylla based gold nan...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
Our present study sought to evaluate hepatoprotective and antioxidant effects of methanol extract of Azolla microphylla phytochemically synthesized gold nanoparticles (GNaP) in acetaminophen (APAP) - induced hepatotoxicity of fresh water common carp fish.
Materials and Methods:
GNaP were prepared by green synthesis method using methanol extract of Azolla microphylla. Twenty four fishes weighing 146 ± 2.5 g were used in this experiment and these were divided into four experimental groups, each comprising 6 fishes. Group 1 served as control. Group 2 fishes were exposed to APAP (500 mg/kg) for 24 h. Groups 3 and 4 fishes were exposed to APAP (500 mg/kg) + GNaP (2.5 mg/kg) and GNaP (2.5 mg/kg) for 24 h, respectively. The hepatoprotective and antioxidant potentials were assessed by measuring liver damage, biochemical parameters, ions status, and histological alterations.
Results:
APAP exposed fish showed significant elevated levels of metabolic enzymes (LDH, G6PDH and MDH), hepatotoxic markers (GPT, GOT and ALP), reduced hepatic glycogen, lipids, protein, albumin, globulin, increased levels of bilirubin, creatinine, and oxidative stress markers (TBRAS, LHP and protein carbonyl), altered the tissue enzymes (SOD, CAT, GSH-Px and GST) non-enzyme (GSH), cellular sulfhydryl (T-SH, P-SH and NP-SH) levels, reduced hepatic ions (Ca2+, Na+ and K+), and abnormal liver histology. It was observe that GNaP has reversal effects on the levels of above mentioned parameters in APAP hepatotoxicity.
Conclusion:
Azolla microphylla phytochemically synthesized GNaP protects liver against oxidative damage and tissue damaging enzyme activities and could be used as an effective protector against acetaminophen-induced hepatic damage in fresh water common carp fish.
APPLICATIONS OF MULTICOMPONENT ASSEMBLY PROCESSES TO THE FACILE SYNTHESES OF ...JamesSahn
Several multicomponent assembly processes have been developed for the synthesis of intermediates that may be elaborated by a variety of cyclizations to generate a diverse array of highly functionalized heterocycles from readily-available starting materials. The overall approach enables the efficient preparation of libraries of small molecules derived from fused, privileged scaffolds. Source: Heterocycles 84:2 2012 pg 1089-1112
Loperamide (LOP) is an antidiarrheal agent that works by slowing gastrointestinal transit and reducing intestinal secretions. The aim of the study is to evaluate the effect of loperamide consumption for five days on the intestinal oxidative balance, as well as the putative protective effect of mallow leaves extract. Animals were divided into one normal control group and fi ve experimental groups. LOP, LOP + the different doses of the extract (100, 200, and 400 mg/ kg, b.w.), and LOP+ yohimbine (2 mg/ kg, b.w. p.i.), used as reference drug. Loperamide (3 mg/ kg, b.w. p.o) was administered twice a day, for 5 days. Treatment with mallow extract or yohimbine protected against the lipid peroxidation, antioxidant enzymes activity depletion, the fall in the thiol group and reduced glutathione level as well as jejunal free iron and H2O2 overload induced by loperamide intoxication. Thereby, Malva sylvestris aqueous extract (MSAE) attenuates the pathogenicity of loperamide.
Polymeric composite membranes for temperature and pH-responsive delivery of d...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
Nowadays hydrogels are one of the upcoming classes of polymer-based controlled-release drug delivery systems. Temperature and pH-responsive delivery systems have drawn much attention because some diseases reveal themselves by a change in temperature and/or pH. The objective of this work is to prepare and characterize composite membrane using responsive nanoparticles into a polymer matrix.
Materials and Methods:
These nanoparticles were made of the copolymer poly (N-isopropylacrylamide-co-methaçrylic acid) by an aqueous dispersion polymerization process and are responsible for dual sensitivity to temperature and pH. Morphology study with SEM, swelling behavior with Dynamic Light Scattering Technique, in vitro drug release behavior with side-by-side Diffusion Cells were also investigated in this paper. Doxorubicin hydrochloride was used as a model solute.
Results:
The study on the release of doxorubicin hydrochloride showed that the release rate was higher at pH 5 than pH 7.4, increased with the increase of temperature. Nevertheless, ionic strength only poses a minor direct effect at higher pH.
Conclusion:
Such system may be potentially used as a tumor-targeting doxorubicin hydrochloride delivery in the body.
Hepatoprotective and antioxidant effects of Azolla microphylla based gold nan...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
Our present study sought to evaluate hepatoprotective and antioxidant effects of methanol extract of Azolla microphylla phytochemically synthesized gold nanoparticles (GNaP) in acetaminophen (APAP) - induced hepatotoxicity of fresh water common carp fish.
Materials and Methods:
GNaP were prepared by green synthesis method using methanol extract of Azolla microphylla. Twenty four fishes weighing 146 ± 2.5 g were used in this experiment and these were divided into four experimental groups, each comprising 6 fishes. Group 1 served as control. Group 2 fishes were exposed to APAP (500 mg/kg) for 24 h. Groups 3 and 4 fishes were exposed to APAP (500 mg/kg) + GNaP (2.5 mg/kg) and GNaP (2.5 mg/kg) for 24 h, respectively. The hepatoprotective and antioxidant potentials were assessed by measuring liver damage, biochemical parameters, ions status, and histological alterations.
Results:
APAP exposed fish showed significant elevated levels of metabolic enzymes (LDH, G6PDH and MDH), hepatotoxic markers (GPT, GOT and ALP), reduced hepatic glycogen, lipids, protein, albumin, globulin, increased levels of bilirubin, creatinine, and oxidative stress markers (TBRAS, LHP and protein carbonyl), altered the tissue enzymes (SOD, CAT, GSH-Px and GST) non-enzyme (GSH), cellular sulfhydryl (T-SH, P-SH and NP-SH) levels, reduced hepatic ions (Ca2+, Na+ and K+), and abnormal liver histology. It was observe that GNaP has reversal effects on the levels of above mentioned parameters in APAP hepatotoxicity.
Conclusion:
Azolla microphylla phytochemically synthesized GNaP protects liver against oxidative damage and tissue damaging enzyme activities and could be used as an effective protector against acetaminophen-induced hepatic damage in fresh water common carp fish.
APPLICATIONS OF MULTICOMPONENT ASSEMBLY PROCESSES TO THE FACILE SYNTHESES OF ...JamesSahn
Several multicomponent assembly processes have been developed for the synthesis of intermediates that may be elaborated by a variety of cyclizations to generate a diverse array of highly functionalized heterocycles from readily-available starting materials. The overall approach enables the efficient preparation of libraries of small molecules derived from fused, privileged scaffolds. Source: Heterocycles 84:2 2012 pg 1089-1112
Application and scope of atom economy green chemistryAhmadUmair14
these are slides are made to explain the scope and applications about green chemistry and atom economy and where they both can be utilized. hope you love it
Science and technology of manipulating and improving microbial strains, in order to enhance their metabolic capacities for biotechnological applications, are referred to as strain improvement.
BIOCATALYST/SAGAR SHARMA/DEPARTMENT OF PHARMACEUTICAL SCIENCES KUKSagarMudgil1
A biocatalyst is a substance that uses enzymes to start chemical reactions that convert organic compounds into other compounds. Biocatalysts are naturally occurring substances that use enzymes from biological sources.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Generating a custom Ruby SDK for your web service or Rails API using Smithyg2nightmarescribd
Have you ever wanted a Ruby client API to communicate with your web service? Smithy is a protocol-agnostic language for defining services and SDKs. Smithy Ruby is an implementation of Smithy that generates a Ruby SDK using a Smithy model. In this talk, we will explore Smithy and Smithy Ruby to learn how to generate custom feature-rich SDKs that can communicate with any web service, such as a Rails JSON API.
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
Kubernetes & AI - Beauty and the Beast !?! @KCD Istanbul 2024Tobias Schneck
As AI technology is pushing into IT I was wondering myself, as an “infrastructure container kubernetes guy”, how get this fancy AI technology get managed from an infrastructure operational view? Is it possible to apply our lovely cloud native principals as well? What benefit’s both technologies could bring to each other?
Let me take this questions and provide you a short journey through existing deployment models and use cases for AI software. On practical examples, we discuss what cloud/on-premise strategy we may need for applying it to our own infrastructure to get it to work from an enterprise perspective. I want to give an overview about infrastructure requirements and technologies, what could be beneficial or limiting your AI use cases in an enterprise environment. An interactive Demo will give you some insides, what approaches I got already working for real.
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
Securing your Kubernetes cluster_ a step-by-step guide to success !KatiaHIMEUR1
Today, after several years of existence, an extremely active community and an ultra-dynamic ecosystem, Kubernetes has established itself as the de facto standard in container orchestration. Thanks to a wide range of managed services, it has never been so easy to set up a ready-to-use Kubernetes cluster.
However, this ease of use means that the subject of security in Kubernetes is often left for later, or even neglected. This exposes companies to significant risks.
In this talk, I'll show you step-by-step how to secure your Kubernetes cluster for greater peace of mind and reliability.
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
But there’s more:
In a second workflow supporting the same use case, you’ll see:
Your campaign sent to target colleagues for approval
If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
Join us to learn more about this new, human-in-the-loop capability, brought to you by Integration Service connectors.
And...
Speakers:
Akshay Agnihotri, Product Manager
Charlie Greenberg, Host
2. 356 K. Stamatelatou et al. / Control strategies for anaerobic digesters
Application of optimal control theory to fermentation • Acetate is the main constituent of the fatty acids.
processes has been an intriguing issue for numerous inves- • Acetate is the key organic compound fed to the digester,
tigators [5–7,13,16,17,19,21–24,29,32]. Many algorithms so that hydrogen utilizing methanogenic bacteria can be
and other methods have also been developed, in order to neglected. This assumption will be exact if acidogene-
overcome the difficulties entailed in applying optimal con- sis and methanogenesis occur separately in a two-stage
trol theory. Most researchers, however, have focused on anaerobic process [1,33]. In this case, the influent of
batch and semi-batch bioreactors. In an attempt to opti- the methanogenic digester can be regulated to consist
mize continuous throughput, as opposed to batch fermenta- mainly of acetate.
tion processes, a different and interesting approach has been • The biomass loss due to bacterial decay is insignificant
followed by D’Ans et al. [5] who applied Green’s theorem compared with the biomass loss due to the operating
to maximize bacterial growth during a transient state. conditions of the reactor (biomass in the effluent), so
A particular issue of importance when it comes to opti- that the endogenous decay term may be neglected [2].
mization of continuous processes, is the fact that the aris-
ing optimal control problem is singular because the control The above assumptions are necessary if we are to be able
variable, i.e., the dilution rate, is linearly included in the to formulate a singular optimal control problem with an el-
state equations [9,10]. Whenever a singular optimal control egant solution being possible. Deviations between real ap-
policy can be explicitly determined, it is rather impractical, plication and the hereby developed theoretical results may
since it usually involves a complicated function of the state be attributed to one or more of the above assumptions not
variables, often not readily measurable on-line. From this being valid.
aspect it is more useful to derive a suboptimal control law We distinguish two cases of disturbances affecting the
expressed in a simpler explicit form, in terms of quantities digester.
which may be measured on-line, and resulting in an imper-
(i) Disturbance caused by inhibitor intrusion to the system
ceptible loss of performance. Pullammanappallil et al. [29]
considered the case of inhibitors entering with the feed in Consider the case where a waste, to be treated anaerobi-
this perspective and presented a suboptimal solution of the cally, contains an inhibitory substance such as chloroform
problem, much simpler in form than the optimal one and or ammonia. Mass balances of biomass, substrate and in-
easy to implement. In this work, we thoroughly examine hibitor constitute the following model equations:
the conventional optimal control problem and its simpli-
dX
fied, suboptimal version when the normal operation of an = −DX + µX, (1)
anaerobic digester is upset by entry of an inhibitor, a feed dt
overload or underload. dS 1
= D(S0 − S) − µX, (2)
dt YX/S
2. Modeling for optimization dI
= D(I0 − I), (3)
dt
Application of optimal control theory requires a mathe- where X, S, I represent the methanogen, volatile fatty acid
matical model for the described process. Detailed modeling and inhibitor concentrations, respectively, D is the dilution
of anaerobic digestion has been the objective of many re- rate, and µ is the specific growth rate. The latter is a com-
searchers for whom their main concern has been a deeper plicated function of the state variables and is assumed to
understanding of the biochemical steps involved in the follow Andrews’ kinetics which predicts inhibition for high
anaerobic processes [3,4,11,20]. Despite the usefulness of substrate concentrations. This is the case for methanogenic
such models, their large dimensionality constitutes a seri- microorganisms since they are strongly inhibited by high
ous disadvantage in handling these models for application concentrations of what they metabolize, i.e., fatty acids:
purposes, especially when development of control schemes µmax
is involved. In such cases, the insight of the control law µ = µ(S) = . (4)
1 + Ks /S + S/Kip
the researcher gets while using a simplified model is more
important than the model itself. In this expression µmax is the maximum specific growth
This is also the case of the present work which necessi- rate, Ks is the saturation constant, and Kip is the substrate
tates the use of a simplified model based on the following inhibition constant.
assumptions: Given that the presence of an inhibitor affects only the
specific growth rate, µ, and the feed substrate concentra-
• All the feed substrate converts into organic acid rapidly, tion (S0 ) does not vary, stoichiometry may be used to
which permits us to neglect the dynamics of all the express volatile fatty acid concentration (S) in terms of
reaction steps except for the rate limiting growth of methanogen concentration, X:
methanogens and the associated production of methane
[27,30]. X = YX/S (S0 − S), (5)
• pH is assumed to be controlled to remain neutral. where YX/S is the yield constant.
3. K. Stamatelatou et al. / Control strategies for anaerobic digesters 357
In view of equation (5), the state variables and, conse- The total methane production over the interval [0, tf ] can
quently, the model equations may be reduced to only two, be expressed as
one for the methanogen concentration, X, or the substrate tf
concentration, S, and one for the inhibitor concentration, I. J D(t) = QCH4 (t) dt, (8)
As a consequence, equations (1) or (2) along with (3) are 0
adequate to describe the process. where QCH4 (t) is the methane production rate, D(t) is
The impact of an inhibitory substance upon anaerobic the dilution rate, and tf is the final time (chosen suffi-
digestion kinetics is expressed by a multiplying factor, i.e., ciently large, so that a new steady state is reached). The
f (I), which generally affects µmax or Ks of the specific methane production rate is assumed to be proportional to
growth rate [2]. The latter is modified as follows: the methanogen growth rate [27,30]
µmax f (I) QCH4 = V YCH4 /X µX, (9)
µ = µ(X, I) = S0 −X/YX/S
, (6)
Ks
1+ S0 −X/YX/S + Kip where V is the volume of the reactor, YCH4 /X is a yield
coefficient, µ is the specific growth rate, and X is the
where it is assumed that inhibition results simply in the methanogen concentration.
reduction of the maximum specific growth rate, i.e., µmax .
A variety of expressions have been suggested for f (I) [14],
among which two are considered in this work: 4. Optimization
f (I) = e−aI (7a) The Hamiltonian function for case (i), i.e., the presence
of an inhibitor in the feed, is
or
H = V YCH4 /X µ(X, I)X + λ1 −DX + µ(X, I)X
1
f (I) = . (7b) + λ2 D(I0 − I), (10)
1 + bI
Relationships (7a) and (7b) are known expressions which while for case (ii), i.e., the feed overload or underload, is
have been reported to account for substrate and/or product
H = V YCH4 /X µ(X, S)X + λ1 −DX + µ(X, S)X
inhibition [14]. Additionally, the latter is already known to
describe the noncompetitive inhibition of enzyme-catalyzed 1
+ λ2 D(S0 − S) − µ(X, S)X , (11)
reaction kinetics [8]. YX/S
where λ1 , λ2 are the co-state variables. The time deriva-
(ii) Disturbance caused by feed overload or feed tive of λi is defined for each case as the negative partial
underload derivative of Hamiltonian with respect to the state variables
(X or S).
In this case, the feed substrate concentration is subjected It is evident that we are dealing with a singular control
to a step change (increase or decrease, respectively), so problem since the Hamiltonian, in both cases, is linear with
that effluent biomass and substrate concentrations are not respect to the manipulated variable, D(t), and therefore for
related stoichiometrically at all times. The model equations all t the optimal D is either on a singular arc or on a bound
are restricted to (1) and (2) with the specific growth rate (either 0 or Dmax , depending on the initial conditions) until
simply given by (4). it reaches a singular arc and remains on that singular arc
until tf .
On the singular arc the following equations are valid:
3. Performance measure
HD = 0, (12)
dHD
The selection of an appropriate performance measure = 0, (13)
for an optimal control problem is the most important fac- dt
tor in an optimization problem definition. It enables us to d2 HD
= 0. (14)
get the most out of a transition state as it arises from the dt2
dynamic conditions prevailing in the digester. In anaero- Equations (12) and (13) are independent of D and may be
bic digestion, if one is primarily interested in the amount of used for expressing the co-state variables in terms of the
generated methane, the total methane production during the state variables, while from equation (14) an expression for
period of transition between two steady states constitutes an D can be derived, which is the optimal (feedback) control
appropriate performance measure to be maximized. In ad- policy on the singular arc (appendix B).
dition, it is an indication of the system robustness, since it In order to solve the optimal control problem, the point
monitors the methanogenic activity throughout the change. where the switching between the bound and the singular
What is more, it is based on the methane production rate arc occurs is of crucial importance. For this reason, we
which can be easily measured on-line. need to have an expression for the state variables which is
4. 358 K. Stamatelatou et al. / Control strategies for anaerobic digesters
valid only on the singular arc, so that while on the bound,
we will be able to check if we have reached the singular
arc. Such an expression can be derived by the following
argument:
Since the Hamiltonian is not an implicit function of time,
its first derivative with respect to time is zero:
˙
H = 0. (15)
As a consequence,
H = constant (16)
throughout the singular arc. It can be easily proved that the
new optimal steady state singular arc is unique, regardless
of tf , upon which the new optimal steady state lies (ap-
pendix C). Clearly, at the final time, tf , when the system
reaches a new optimal steady state corresponding to the
new feed conditions, the Hamiltonian will be equal to H ∗
(from (10) or (11) at the steady state), which is the value
of the constant in (16):
H ∗ = V YCH4 /X µ∗ X ∗ , (17)
Figure 1. Inhibitors entering with the feed: Optimal trajectory.
where the ∗ denotes the value of these quantities at the
new optimal steady state. In this way, equation (16) gives
an expression for the singular arc with respect to the state
variables.
It should be mentioned that the manipulated variable, D,
is constrained between two bounds – zero (equivalent to
batch operation) and Dmax , given by
Fmax
Dmax = , (18)
V
where Fmax is the maximum flowrate the feeding pump may
provide, and V is the volume of the reactor vessel. The
above constraint has an implication for the case in which
the first calculated value of the dilution rate on the singular
arc is higher than Dmax . In such a case, the optimal control
policy is a bang–bang control policy (sequential switching
between the upper and lower bounds) until the calculated
dilution rate on the singular arc lies within the limits.
5. Optimal and easily implementable suboptimal
control laws
An arithmetic example following the procedure de- Figure 2. Step change in the feed substrate concentration: Optimal trajec-
tory.
scribed above for each type of disturbance considered is
presented in this section. The values of the constants and
the other parameters of the problem are given in appen- leads the system optimally to the new optimal steady state,
dix A. The analytical forms of the basic relationships of by changing the dilution rate according to equations (B4)
the problem are presented in appendix B. or (B8).
Figures 1 and 2 present the transition phase plane for the A typical time evolution of the optimal dilution rate and
cases of the intrusion of an inhibitor, the effect of which on the corresponding methane production rate for the cases
the specific growth rate is given by (7a), and a disturbance examined is depicted in figures 3 and 4.
at the feed substrate concentration, respectively. Immedi- It should be mentioned that if instead of (7a) we mod-
ately following an imbalance, the digester operates either eled the effect of the inhibitors on the specific growth rate
as a batch reactor (D = 0) or as a CSTR at its maximum through (7b), we would obtain qualitatively similar results
capacity (D = Dmax ), until it reaches the singular arc that with those presented in figures 1 and 3.
5. K. Stamatelatou et al. / Control strategies for anaerobic digesters 359
Figure 3. Inhibitors entering with the feed: Optimal dilution rate and
methane production rate versus time.
Still practical problems arise when it comes to enforcing
the optimal control law, since it requires the knowledge of
the state variables which cannot easily be measured on-line.
As an alternative, a good suboptimal and easy to imple-
ment control law has been formulated.
Figures 3 and 4 indicate that almost for the entire interval
of optimization, the optimal trajectory lies on the singular
arc excluding a negligibly small initial interval when the
control variable is on a bound. The plot of the generated
methane production rate versus dilution rate while on the
singular arc is almost a straight line which passes through
the origin of the axes as can be seen from figures 5 and 6.
Thus, the suboptimal control policy that results is to sim-
ply change the dilution rate proportionally to the methane
production rate which can be readily measured on-line, i.e.,
D(t) = kQCH4 (t). (19)
Here k is the proportionality constant which can be deter-
mined by estimating the slope of the straight line of fig-
ures 5 and 6. A very good approximation of this optimal
value of k can be easily determined by the ratio of dilution Figure 4. Step change in the feed substrate concentration: (a) Optimal
dilution rate versus time; (b) optimal methane production rate versus time.
rate to methane production rate under optimal operating
conditions at the new steady state.
Equation (19) is not only easy to enforce but is also
Table 1
a very good suboptimal control law as indicated by the Performance measure values indicating the total methane produced while
comparison of the performance estimated for both control implementing the optimal or the suboptimal control law.
policies which have been implemented for each type of dis-
Kind of disturbance Performance measure, J
turbance. This comparison is presented in table 1, where (total methane, l)
the insignificant difference between the optimal and the sub-
optimal solution of the problem establishes the credibility Optimal Suboptimal
and value of the suboptimal control law. Inhibitor intrusion 302.19 302.17
In the examples with a step change in the feed substrate Overload 852.09 852.08
concentration presented here, the optimal dilution rate val- Underload 561.08 561.07
ues of the initial and the final steady state are almost iden-
6. 360 K. Stamatelatou et al. / Control strategies for anaerobic digesters
Figure 7. Feed substrate underload (from 1000 to 100 mg/l): Methane
Figure 5. Inhibitors entering with the feed: Methane production rate production rate versus dilution rate.
versus dilution rate.
here but also in a wide variety of situations. A feature of
the cases considered in this work, involves a permanent ef-
fect (step change) of a selected disturbance on the system
so that its operation has to be established at a new steady
state. Even if this disturbance lasted only for a finite pe-
riod of time (pulse change), implementation of (19) would
lead the digester to its original steady state in an almost
optimal way. The suboptimal control law given by (19)
has been incorporated in an expert system developed by
Pullammanappallil et al. [28] for stabilizing anaerobic di-
gesters. This work, therefore, really comes to justify that
particular choice made.
6. Conclusions
Operation of anaerobic digesters is sensitive to a variety
of disturbances, which may lead the digester to wash out.
An optimal control policy should be addressed to avoid the
impeding digester failure and restore its normal operation or
lead it to a new optimal steady state. This has been accom-
Figure 6. Step change in the feed substrate concentration: Methane pro-
duction rate versus dilution rate.
plished by using a simplified model of anaerobic digestion
to determine the optimal dilution rate as a function of time,
tical due to the fact that the initial and final feed substrate in response to the entry of an inhibitor with the feed or a
concentration values were specifically high. Nevertheless, sudden change in the feed substrate concentration. By ex-
even in the case this almost identity does not occur, the amining the essential features of the digester key operating
relationship between methane production rate and dilution variables, a simpler and easily implementable suboptimal
rate on the singular arc is still almost linear as can be seen control law was derived, according to which the dilution
in figure 7, and consequently the suboptimal control law rate should be changed proportionally to the methane pro-
can be used instead. duction rate, with the gain determined from the new optimal
The concept of this suboptimal control policy is not only steady state values. This suboptimal controller, with a wide
valid in the specific formulation of the problem presented field of enforcement, leads to almost optimal performance.
7. K. Stamatelatou et al. / Control strategies for anaerobic digesters 361
Appendix A Feed overload
Constant and parameter values Step change in the feed substrate concentration from 20
to 30 g/l;
a = 1 l/mg,
b = 1.77 l/mg, S0 = 30 000 mg/l.
Kip = 4 000 mg/l, Initial conditions:
Ks = 20 mg/l,
V = 5 l, S = 254.887 mg/l,
YX/S = 0.035 mg biomass/mg substrate, X = 691.079 mg/l.
YCH4 /X = 0.009 l methane/mg biomass,
µmax = 0.36 day−1 . Feed underload
Inhibitors entering with the feed Step change in the feed substrate concentration from 30
to 20 g/l;
I0 = 1 mg/l,
S0 = 20 000 mg/l.
S0 = 25 000 mg/l.
Initial conditions: Initial conditions:
I = 0 mg/l, S = 263.342 mg/l,
X = 856.905 mg/l. X = 1040.783 mg/l.
Appendix B. Optimal control law on the singular arc
(I) Inhibitors entering with the feed
(i) Costate variables:
µ(X, I)
λ1 = V YCH4 /X −1 , (B1)
∂µ(X,I)
∂I (I0 − I) − ∂µ(X,I)
∂X X
µ(X, I) X
λ2 = V YCH4 /X −1 . (B2)
∂µ(X,I)
∂I (I0 − I) − ∂µ(X,I)
∂X X
I0 − I
(ii) Equation of singular arc:
µ(X, I)2X
V YCH4 /X = constant. (B3)
∂µ(X,I)
∂I (I0 − I) − ∂µ(X,I) X
∂X
(iii) Dilution rate expression:
2
∂ 2 µ(X, I) ∂µ(X, I)
D= µ(X, I)2 − 2 µ(X, I) X 2
∂X 2 ∂X
∂µ(X, I) ∂µ(X, I) ∂ 2 µ(X, I) ∂µ(X, I)
+ 2 µ(X, I) − µ(X, I)2 (I0 − I)X + µ(X, I)2 (I0 − I)
∂X ∂I ∂X∂I ∂I
2
∂ 2 µ(X, I) ∂µ(X, I) ∂µ(X, I) ∂µ(X, I) ∂ 2 µ(X, I)
× µ(X, I) − 2 X2 + 4 −2 µ(X, I) (I0 − I)X
∂X 2 ∂X ∂X ∂I ∂X∂I
2 −1
∂ 2 µ(X, I) ∂µ(X, I)
+ µ(X, I) − 2 (I0 − I) 2
. (B4)
∂I 2 ∂I
8. 362 K. Stamatelatou et al. / Control strategies for anaerobic digesters
(II) Step change in the feed substrate concentration
(i) Costate variables:
µ(S) − ∂µ(S)
∂S (S0 − S)
λ1 = V YCH4 /X , (B5)
∂µ(S)
∂S (S0 − S) − X
YX/S
µ(S) − ∂µ(S)
∂S (S0 − S)
λ2 = V YCH4 /X X. (B6)
∂µ(S)
∂S (S0 − S) (S0 − S) − X
YX/S
(ii) Equation of singular arc:
µ(S)2
V YCH4 /X X = constant. (B7)
∂µ(S)
∂S (S0 − S)
(iii) Dilution rate expression:
2
∂µ(S) ∂ 2 µ(S) ∂µ(S) X ∂µ(S)
D= 2 µ(S)(S0 − S) − µ(S)2 (S0 − S) + µ(S)2 − µ(S)2 (S0 − S)
∂S ∂S 2 ∂S YX/S ∂S
2 −1
∂µ(S) ∂ 2 µ(S)
× 2 − µ(S) (S0 − S)2 . (B8)
∂S ∂S 2
Appendix C. Proof that the new optimal steady state Consequently, the optimal steady state is one for which
lies on the singular arc (C1)–(C3) are satisfied. On substitution of these expres-
sions into equations (12)–(14) it can be observed that they
This is shown for the case where an inhibitor intrudes are all satisfied. Moreover, the optimal steady state also sat-
into the digester. The same applies for the underload or ˙ ˙
isfies X = 0 and I = 0 and thus all optimality conditions
overload case. are met.
The state equations are:
X = −DX + µ(X, I)X,
˙ References
I = D(I0 − I).
˙
[1] A. Aivasidis, Proceedings of Conference on Industrial Wastewater
Treatment and Disposal, University of Patras, Greece (21–22 No-
At steady state, vember 1996) pp. 127–137.
[2] I.M. Alatiqi, A.A. Dadkhah and N.M. Jabr, Chem. Engrg. J. 43
D = µ(X, I), (C1) (1990) B81.
[3] J.F. Andrews and S.F. Graef, in: Anaerobic Biological Treatment
I = I0 . (C2) Processes, Advances in Chemistry Series, Vol. 105 (American
Chemical Society, Washington, 1971) p. 126.
For optimality we have: [4] I. Angelidaki, L. Ellegaard and B.K. Ahring, Biotech. Bioengrg. 42
(1993) 159.
dJSS dµ(X, I)X [5] G.D. Ans, P. Kokotovic and D. Cottlieb, IEEE Trans. Automat. Con-
= V YCH4 /X =0
dD dD trol 16 (1971) 341.
[6] G.D. Ans, P. Kokotovic and D. Cottlieb, Journal of Optimization
∂µ(X, I)X ∂µ(X, I)X dI
⇒ + Theory and Applications 7 (1971) 61.
∂D ∂I dD [7] G.D. Ans, P. Kokotovic and D. Cottlieb, Automatica 8 (1972) 729.
∂µ(X, I)X dX [8] J.E. Bailey and D.F. Ollis, Biochemical Engineering Fundamentals
+ = 0. (McGraw Hill, Singapore, 1986).
∂X dD [9] D.J. Bell and D.H. Jacobson, in: Singular Optimal Control Prob-
In the above equation lems, Mathematics in Science and Engineering, Vol. 117 (Academic
Press, 1975).
∂µ(X, I)X [10] A.E. Bryson and Y.J. Ho, Applied Optimal Control (Halsted Press,
= 0, Willey, 1975).
∂D
[11] D.J. Costello, P.F. Greenfield and P.L. Lee, Water Res. 25 (1991)
and at steady state I is independent of D, i.e., dI/dD = 0. 847.
Since dX/dD = 0, [12] D. Dochain, G. Bastin, A. Rozzi and A. Pauss, in: Adaptive Estima-
tion and Control of Biotechnological Processes, eds. S.L. Dhah and
∂µ(X, I)X G. Dumont, Adaptive Control Strategies for Industrial Use (Springer,
= 0. (C3) Berlin, 1989).
∂X
9. K. Stamatelatou et al. / Control strategies for anaerobic digesters 363
[13] R. Guthke and W.A. Knorre, Biotech. Bioengrg. 23 (1981) 2771. Water Quality Management Library, Vol. 7 (Technomic Publishing
[14] K. Han and O. Levenspiel, Biotech. Bioengrg. 32 (1988) 430. Company, 1992).
[15] J. Harmon, P. Pullammanappallil, G. Lyberatos, S.A. Svoronos and [26] F.M. Podruzny and L. van den Berg, Biotech. Bioengrg. 26 (1984)
D.P. Chynoweth, Proc. Amer. Control Conf. 2 (1990) 2156. 392.
[16] O. Hiromu, E. Nakanishi and T. Takamatsu, Biotech. Bioengrg. 18 [27] M. Polihronakis, L. Petrou and A. Deligiannis, Comp. Chem. Engrg.
(1976) 847. 17 (1993) 1167.
[17] L.Y. Ho and A.E. Humphrey, Biotech. Bioengrg. 12 (1970) 291. [28] P. Pullammanappallil, J. Harmon, D.P. Chynoweth, G. Lyberatos and
[18] I.S. Kim, J.C. Young and H.H. Tabak, Water Environ. Res. 66 (1994) S.A. Svoronos, Appl. Biochem. Biotech. 28/29 (1991) 33.
119. [29] P. Pullammanappallil, S.A. Svoronos and G. Lyberatos, Proc. ACC
[19] L.C. Liu, G.J. Prokopakis and J.A. Asenjo, in: 7th ALCHE Annual (1991) 1341.
Meeting, Florida (1986). [30] P. Renard, D. Dochain, G. Bastin, H. Naveau and E.J. Nyns, Biotech.
[20] P.L. McCarty and F.E. Mosey, Water Sci. Technol. 24 (1991) 17. Bioengrg. 31 (1988) 287.
[21] J.M. Modak and H.C. Lim, Biotech. Bioengrg. 30 (1987) 528. [31] A. Rozzi, A.C. Di Pinto and A. Brunetti, Environ. Technol. Lett. 6
[22] J.M. Modak and H.C. Lim, Biotech. Bioengrg. 33 (1989) 11. (1985) 594.
[23] R. Mutharasan and D.R. Coughanowr, in: Singular Optimal Con- [32] J. Staniˇkis and D. Leviˇauskas, Biotech. Bioengrg. 25 (1983) 985.
s s
trol of Bioreactors, Proc. 194th National Meeting of the American [33] A.M. Viturtia, P.L. Luengo, F. Cecchi and J.M. Alvarez, Environ.
Society Division of Microbial and Biochemical Technology (1987). Technol. 16 (1995) 379.
[24] S.H. Park, S.B. Lee and R.D.Y. Ryu, Biotech. Bioengrg. 23 (1981) [34] T.N. Whitmore and D. Lloyd, Biotech. Lett. 8 (1986) 203.
1237. [35] T.N. Whitmore, D. Lloyd, G. Jones and T.N. Williams, Appl. Mi-
[25] J. Patterson, in: Design of Anaerobic Processes for the Treatment of crob. Bioengrg. 26 (1987) 383.
Industrial and Municipal Wastes, eds. J.F. Malina and F.G. Pohland,