High gravity batch and continuous processes for beer production: Evaluation of fermentation performance and beer quality

This study deals with two innovative brewing processes, high gravity batch and complete continuous beer fermentation systems. The results show a significant influence of the variables such as concentration and temperature on the yield factor of the substrate into ethanol and consequently on the productivity of the high gravity batch process. The technological feasibility of continuous production of beer based on yeast immobilization on cheap alternative carriers was also demonstrated. The influence of process parameters on fermentation performance and quality of the obtained beers was studied by sensorial analysis. No significant difference in the degree of acceptance between the obtained products and some traditional market brands was found. (c) 2008 Institute of Chemistry, Slovak Academy of Sciences.

Self-dual continuous processes

The important application of semi-static hedging in financial markets naturally leads to the notion of conditionally quasi self-dual processes which is, for continuous semimartingales, related to conditional symmetry properties of both their ordinary as well as their stochastic logarithms. We provide a structure result for continuous conditionally quasi self-dual processes. Our main result is to give a characterization of continuous Ocone martingales via a strong version of self-duality.

A property of stongly continuous processes.

Mode of access: Internet.

Synthesis of galacto-oligosaccharide from lactose using beta-galactosidase from Kluyveromyces lactis: studies on batch and continuous UF membrane-fitted bioreactors

A study of galacto-oligosaccharides (GOS) synthesis from lactose with beta-galactosidase from Kluyveromyces lactis (Maxilact(R) L2000) was carried out. The synthesis was performed using various initial lactose concentrations ranging from 220 to 400 mg/mL and enzyme concentrations ranging from 3 to 9 U/mL, and was investigated at 40degreesC and pH 7, in a stirred-tank reactor. In the experimental range examined, the results showed the amount of GOS formed depended on lactose concentration but not on enzyme concentration. Galactose was a competitive inhibitor, while glucose was a non-competitive inhibitor. In a further study, a laboratory-scale reactor system, fitted with a 10-kDa NMWCO composite regenerated cellulose membrane, was used in a continuous process. The reactor was operated in cross-flow mode. The effect of operating pressures on flux and productivity was investigated by applying different transmembrane pressures to the system. The continuous process showed better production performance compared to the batch synthesis with the same lactose and enzyme concentrations at 40degreesC, pH 7. Comparison of product structures from batch and continuous processes, analyzed by HPAEPAD and methylation analysis, showed similarities but differed from the structures found in a commercial GOS product (Vivinal(R)GOS). (C) 2004 Wiley Periodicals, Inc.

Optimal control and operation of drum granulation processes

Process optimisation and optimal control of batch and continuous drum granulation processes are studied in this paper. The main focus of the current research has been: (i) construction of optimisation and control relevant, population balance models through the incorporation of moisture content, drum rotation rate and bed depth into the coalescence kernels; (ii) investigation of optimal operational conditions using constrained optimisation techniques; (iii) development of optimal control algorithms based on discretized population balance equations; and (iv) comprehensive simulation studies on optimal control of both batch and continuous granulation processes. The objective of steady state optimisation is to minimise the recycle rate with minimum cost for continuous processes. It has been identified that the drum rotation-rate, bed depth (material charge), and moisture content of solids are practical decision (design) parameters for system optimisation. The objective for the optimal control of batch granulation processes is to maximize the mass of product-sized particles with minimum time and binder consumption. The objective for the optimal control of the continuous process is to drive the process from one steady state to another in a minimum time with minimum binder consumption, which is also known as the state-driving problem. It has been known for some time that the binder spray-rate is the most effective control (manipulative) variable. Although other possible manipulative variables, such as feed flow-rate and additional powder flow-rate have been investigated in the complete research project, only the single input problem with the binder spray rate as the manipulative variable is addressed in the paper to demonstrate the methodology. It can be shown from simulation results that the proposed models are suitable for control and optimisation studies, and the optimisation algorithms connected with either steady state or dynamic models are successful for the determination of optimal operational conditions and dynamic trajectories with good convergence properties. (c) 2005 Elsevier Ltd. All rights reserved.

Mathematical Modeling for Studying Microbial Processes – Some Examples

Mathematical modeling may have different purposes in chemical and biochemical engineering sciences. One of them is to confirm or to reject kinetic models for certain processes, or to evaluate the importance of some transport phenomena on the net chemical or biochemical reaction rate. In the present paper different microbial processes are considered and modeled for evaluation of kinetic constants for batch and continuous processes accomplished by free and immobilized microbial cells. The practical examples are from the field of wastewater treatment and biosynthesis of products, like enzymes, lactic acid, gluconic acid, etc. By the aid of mathematical modeling the kinetics and the type of inhibition are specified for microbial wastewater denitrification and biodegradation of halogenated hydrocarbons. The importance of free and immobilized cells and their separate contribution to the overall microbial process is also evaluated for some fermentation processes: gluconic acid production, dichloroethane biodegradation, lactic acid fermentation and monochloroacetic acid biodegradation.

Modular continuous crystallizer: operation, experimental arrangement and identification of process parameters

Crystallization is employed in different industrial processes. The method and operation can differ depending on the nature of the substances involved. The aim of this study is to examine the effect of various operating conditions on the crystal properties in a chemical engineering design window with a focus on ultrasound assisted cooling crystallization. Batch to batch variations, minimal manufacturing steps and faster production times are factors which continuous crystallization seeks to resolve. Continuous processes scale-up is considered straightforward compared to batch processes owing to increase of processing time in the specific reactor. In cooling crystallization process, ultrasound can be used to control the crystal properties. Different model compounds were used to define the suitable process parameters for the modular crystallizer using equal operating conditions in each module. A final temperature of 20oC was employed in all experiments while the operating conditions differed. The studied process parameters and configuration of the crystallizer were manipulated to achieve a continuous operation without crystal clogging along the crystallization path. The results from the continuous experiment were compared with the batch crystallization results and analysed using the Malvern Morphologi G3 instrument to determine the crystal morphology and CSD. The modular crystallizer was operated successfully with three different residence times. At optimal process conditions, a longer residence time gives smaller crystals and narrower CSD. Based on the findings, at a constant initial solution concentration, the residence time had clear influence on crystal properties. The equal supersaturation criterion in each module offered better results compared to other cooling profiles. The combination of continuous crystallization and ultrasound has large potential to overcome clogging, obtain reproducible and narrow CSD, specific crystal morphologies and uniform particle sizes, and exclusion of milling stages in comparison to batch processes.

Improved nitrogen removal by application of new nitrogen-cycle bacteria

In order to meet increasingly stringent European discharge standards, new applications and control strategies for the sustainable removal of ammonia from wastewater have to beimplemented. In this paper we discuss anitrogen removal system based on the processesof partial nitrification and anoxic ammoniaoxidation (anammox). The anammox process offers great opportunities to remove ammonia in fully autotrophic systems with biomass retention. No organic carbon is needed in such nitrogenremoval system, since ammonia is used a selectron donor for nitrite reduction. The nitrite can be produced from ammonia in oxygen-limited biofilm systems or in continuous processes without biomass retention. For successful implementation of the combined processes, accurate biosensors for measuring ammonia and nitrite concentrations, insight inthe complex microbial communities involved, and new control strategies have to be developed and evaluated.

Inova????o no governo e no setor p??blico: desafios e implica????es para a lideran??a

Pol??ticas de inova????o no governo e no setor p??blico s??o necess??rias por muitas raz??es. As institui????es de governan??a, incluindo-se a?? as organiza????es de servi??o p??blico, v??m enfrentando atualmente in??meros desafios e devem exercer suas atribui????es a partir desse contexto. S??o desafios que requerem abordagens novas e inovadoras para dar conta de sua complexidade. ?? preciso, portanto, que governos e servi??os p??blicos se envolvam em processos cont??nuos de inova????o: solu????es convencionais e conhecidas parecem simplesmente n??o mais atender e somente se conseguir?? fazer frente aos novos desafios com sucesso por meio de respostas criativas. Surge, ent??o, uma quest??o: quais as abordagens e as estrat??gias de lideran??a mais indicadas em um contexto de necess??ria inova????o? Este artigo trata dos desafios que surgem a partir desse contexto e dos aspectos de inova????o necess??rios para enfrent??-los. Apresenta ainda algumas abordagens de lideran??a e poss??veis estrat??gias para aumentar a capacidade de lideran??a p??blica e a habilidade dos l??deres, para que enfrentem os desafios de inovar e de implementar pol??ticas e processos inovadores.

Improving downstream processing for viral vectors and viral vaccines

Viral vectors are playing an increasingly important role in the vaccine and gene therapy elds. The broad spectrum of potential applications, together with expanding medical markets, drives the e orts to improve the production processes for viral vaccines and viral vectors. Developing countries, in particular, are becoming the main vaccine market. It is thus critical to decrease the cost per dose, which is only achievable by improving the production process. In particular advances in the upstream processing have substantially increased bioreactor yields, shifting the bioprocess bottlenecks towards the downstream processing. The work presented in this thesis aimed to develop new processes for adenoviruses puri cation. The use of state-of-the-art technology combined with innovative continuous processes contributed to build robust and cost-e ective strategies for puri cation of complex biopharmaceuticals.(...)

Application of multivariate statistical process control to fuel cell manufacturing

Univariate statistical control charts, such as the Shewhart chart, do not satisfy the requirements for process monitoring on a high volume automated fuel cell manufacturing line. This is because of the number of variables that require monitoring. The risk of elevated false alarms, due to the nature of the process being high volume, can present problems if univariate methods are used. Multivariate statistical methods are discussed as an alternative for process monitoring and control. The research presented is conducted on a manufacturing line which evaluates the performance of a fuel cell. It has three stages of production assembly that contribute to the final end product performance. The product performance is assessed by power and energy measurements, taken at various time points throughout the discharge testing of the fuel cell. The literature review performed on these multivariate techniques are evaluated using individual and batch observations. Modern techniques using multivariate control charts on Hotellings T2 are compared to other multivariate methods, such as Principal Components Analysis (PCA). The latter, PCA, was identified as the most suitable method. Control charts such as, scores, T2 and DModX charts, are constructed from the PCA model. Diagnostic procedures, using Contribution plots, for out of control points that are detected using these control charts, are also discussed. These plots enable the investigator to perform root cause analysis. Multivariate batch techniques are compared to individual observations typically seen on continuous processes. Recommendations, for the introduction of multivariate techniques that would be appropriate for most high volume processes, are also covered.

Suolan pesu ja liuottimen strippaus selluloosaeetteristä

Työssä tutkittiin suolan pesua ja liuottimen strippausta selluloosaeetteristä. Työn tavoitteena oli tutkia erään selluloosaeetterin ominaisuuksien vaikutusta pesuun ja strippaukseen. Strippauksesta selvitettiin pääasiallisesti alipaineen ja lämpötilan vaikutusta tarvittavaan höyrymäärään. Työn kirjallisuusosassa tarkasteltiin selluloosaeetterin valmistuksen teoriaa, pesu- ja strippausprosesseihin vaikuttavia muuttujia sekä erilaisia pesu- ja strippausprosesseihin soveltuvia laitteita. Kokeet suoritettiin pilotlaitoksellaja kahdella tuotantolinjalla. Pilotlaitos oli panosprosessi ja tuotantolinjat olivat jatkuvatoimisia prosesseja. Kokeiden analyysitulokset käsiteltiin lineaarisella regressioanalyysillä. Analyysitulosten perusteella todettiin strippausalipaineen kasvun ja -lämpötilan noston lisäävän tarvittavaa höyrymäärää strippauksessa. Myös stripattavan selluloosaeetterin kosteuspitoisuuden kasvun havaittiin lisäävän tarvittavaa höyrymäärää strippauksessa.

Organisaatiokulttuurin muutoksista viestiminen 1970- luvulta nykypäivään. Case UPM- Kymmene Oyj/ Kaukas

Tässä tutkielmassa on tarkasteltu organisaatiokulttuurin muuttumista ja siitä viestimistä case- yrityksessä. Tutkielman tavoitteena on ollut hahmottaa kuva yrityksen virallisesta tavasta viestiä muutoksista henkilöstölle ja ulkopuolisille intresseille. Tutkimusmenetelmänä on käytetty henkilöstölehtien sisältöanalyysia. Henkilöstölehtiä on tarkasteltu vuosilta 1974- 98 Organisaatiokulttuurin muuttuminen on monivaiheinen ja alati jatkuva prosessi. Jokainen organisaatiokulttuuri muuttaa muotoaan tarkoituksellisesti tai ilman, toiset nopeammin, toiset hitaammin. Yritysten tavoitteena muutoksissa on luoda ja ylläpitää vahvaa organisaatiokulttuuria, jonka voimin yritys selviää paremmin suuristakin muutoksista. Organisaatiokulttuuri on jatkuvasti muuttuva ja muutettava kokonaisuus, joka vaikuttaa kaikkeen organisaatiossa ja jota muovaavat niin yrityksen sisäiset kuin ulkoisetkin asiat. Johdon velvollisuutena on välittää informaatiota muutoksista henkilöstölle ja muille sidosryhmille oikeaan aikaan ja oikealla tavalla.

Mechanistic population Models in Biology: Model Derivation and Application

In general, models of ecological systems can be broadly categorized as ’top-down’ or ’bottom-up’ models, based on the hierarchical level that the model processes are formulated on. The structure of a top-down, also known as phenomenological, population model can be interpreted in terms of population characteristics, but it typically lacks an interpretation on a more basic level. In contrast, bottom-up, also known as mechanistic, population models are derived from assumptions and processes on a more basic level, which allows interpretation of the model parameters in terms of individual behavior. Both approaches, phenomenological and mechanistic modelling, can have their advantages and disadvantages in different situations. However, mechanistically derived models might be better at capturing the properties of the system at hand, and thus give more accurate predictions. In particular, when models are used for evolutionary studies, mechanistic models are more appropriate, since natural selection takes place on the individual level, and in mechanistic models the direct connection between model parameters and individual properties has already been established. The purpose of this thesis is twofold. Firstly, a systematical way to derive mechanistic discrete-time population models is presented. The derivation is based on combining explicitly modelled, continuous processes on the individual level within a reproductive period with a discrete-time maturation process between reproductive periods. Secondly, as an example of how evolutionary studies can be carried out in mechanistic models, the evolution of the timing of reproduction is investigated. Thus, these two lines of research, derivation of mechanistic population models and evolutionary studies, are complementary to each other.

Selvitys erilaisten mäntyöljynkeittoprosessien toiminnasta

Työn tavoitteena oli tutustua eri mäntyöljyprosessien toimintaan. Sulfaattisellun valmistuksessa syntyy sivutuotteena mäntyöljyä. Se tuo lisätuottoa sellutehtaalle. Nykypäivänä mäntyöljyn valmistukseen on kiinnitetty yhä enemmän huomiota uusien jalostusmahdollisuuksien vuoksi. Mäntyöljyä syntyy, kun mustalipeän pinnalta kuorittu suopa palstoitetaan sopivalla hapolla. Suopa koostuu puun uuteaineista eli hartsi- ja rasvahapoista sekä saippuattomista aineista. Suopa pitää erottaa mustalipeästä mahdollisimman hyvin, jotta se ei aiheuttaisi ongelmia sellutehtaan eri prosessin vaiheissa. Suopaa voidaan erottaa mustalipeästä säiliöerotuksena, sentrifugeilla tai hydrosykloneilla. Suovan palstoitusprosessi voi olla erä- tai jatkuvatoiminen prosessi. Jatkuvatoimisia prosesseja ovat: sentrifugi-, säiliödekantointi- ja HDS-prosessi. Mäntyöljyä voidaan käyttää kemianteollisuuden raaka-aineena tai siitä voidaan jalostaa biodieseliä. Tämä biodiesel on niin sanottua toisen polven biopolttoainetta eli se ei sisällä ravinnoksi kelpaavaa raaka-ainetta. Nykypäivänä markkinoilla on sekä eräkeitto- sekä jatkuvatoimisia prosesseja. Suovan erotussäiliöiden rinnalle on tullut uusi sentrifugeilla tapahtuva suovan erotussysteemi.