Safe design and operation of fluidized-bed reactors: Choice between reactor models

For three different catalytic fluidized bed reactor models, two models presented by Werther and a model presented by van Deemter, the region of safe and unique operation for a chosen reaction system was investigated. Three reaction systems were used: the oxidation of benzene to maleic anhydride, the oxidation of naphthalene to phthalic anhydride, and the oxidation of ethylene to ethylene oxide. Predictions of the optimal yield, the operating temperature and the conversion were also subjects of our study. It appeared that for reactions carried out in a fluidized bed operating under conditions of good fluidization all models predicted the same region of safe and unique operation. For a well-designed fluidized bed only the constraint of uniqueness is affected by the reactor model chosen. Predictions of the yield, conversion and operating temperature appeared to fit slightly less well. But still a good indication can be obtained from any of the models since the deviation in the results was less then a few percent for all three reaction systems. The strongest deviations between the models occurs in the region of gas loads only slightly higher than the minimum fluidization velocity. As the heat transfer characteristics are bad at low gas loads this region is unsuitable for highly exothermic reactions where large amounts of heat have to be removed by the coolant. In the region of good heat transfer with gas loads at least several times higher than the minimum the three models predict the same results. For this reason we finally recommed the use of simple models

Safe design of cooled tubular reactors for exothermic multiple reactions: Multiple-reaction networks

The model of the pseudo-homogeneous, one-dimensional cooled tubular reactor is applied to a multiple-reaction network. It is demonstrated for a network which consists of two parallel and two consecutive reactions. Three criteria are developed to obtain an integral yield which does not deviate more than a chosen fraction from the maximum yield that can be obtained in an isothermal reactor. The criteria enable us to choose relevant design and operating conditions for the safe execution of a reaction network in a tubular reactor. The method is illustrated for the production of maleic anhydride by air oxidation of benzene

Safe design and operation of tank reactors for multiple-reaction networks: uniqueness and multiplicity

A method is developed to design a tank reactor in which a network of reactions is carried out. The network is a combination of parallel and consecutive reactions. The method ensures unique operation. Dimensionless groups are used which are either representative of properties of the reaction system or exclusively of the design and operating variables. In a plot of the optimal yield vs the dimensionless operating temperature the region is indicated where operation under conditions of uniqueness is feasible. The method is illustrated with an example: the air oxidation of benzene of maleic anhydride

Biofeedback systems for stress reduction: Towards a Bright Future for a Revitalized Field

Stress has recently been baptized as the black death of the 21st century, which illustrates its threat to current health standards. This article proposes biofeedback systems as a means to reduce stress. A concise state-ofthe-art introduction on biofeedback systems is given. The field of mental health informatics is introduced. A compact state-of-the-art introduction on stress (reduction) is provided. A pragmatic solution for the pressing societal problem of illness due to chronic stress is provided in terms of closed loop biofeedback systems. A concise set of such biofeedback systems for stress reduction is presented. We end with the identification of several development phases and ethical concerns

European lessons for Green and Blue Services in The Netherlands

Green and Blue Services were developed in The Netherlands to reward farmers for the environmental services they provide to society. Especially the first initiatives were area specific, developed together with farmers and different from the national Agri-environmental scheme. In the PLUREL case study region Haaglanden, Green and Blue Services are seen as a strategy to strengthen agriculture in the urban fringe

The Subject of Desire and the Hermeneutics of Thoughts: Foucault’s Reading of Augustine and Cassian in Confessions of the Flesh

Although Foucault presented History of Sexuality Vol. 4: Confessions of the Flesh as a crucial part in the study of the genealogy of the subject of desire, Foucault’s analyses of early Christian doctrine and pastoral technologies do not support the claim that an analytic of the subject of desire was established in early Christianity. This can be shown through a reconstruction of his readings of Augustine and Cassian. Augustine’s doctrinal views of the human condition and the association of libido and disobedience to law are not accompanied by the production of technologies for the hermeneutics of desire. Cassian’s pastoral technologies of obedience and subjection to the will of the spiritual director are organized around the hermeneutics of thoughts, and they aim at establishing an inner detachment from misleading thoughts through examination of conscience. This reconstruction opens new trajectories for a genealogy of the subject of desire and for a genealogy of pastoral power and governmentality

The development of improved and new in vitro assays for detecting the genotoxic and non-genotoxic carcinogenic potential of chemicals in the discovery phase of drug development

In drug development, toxicity is an important factor for attrition, resulting in a failure rate of 30%-40%. Hepatotoxicity, nephrotoxicity, cardiovascular safety, reproduction toxicity, developmental toxicity (teratogenicity), genotoxicity and carcinogenicity are the main causes for attrition in safety assessment. Screening on these aspects in the early discovery phase of drug development and using these data for compound optimization and deselection might result in drug development candidates with an improved success rate. The present thesis focused on early screening for genotoxicity and carcinogenicity. In recent years some progress has been made with assays to assess genotoxicity and non-genotoxic carcinogenicity at the end of the discovery phase. However, the time point at which these genotoxicity and carcinogenicity assays are performed is still relatively late, only a few assays for such a strategy are available, the throughput of these assays is in general still low and most of them have not yet been validated extensively. An additional drawback is that the currently used in vitro assays for the detection of genotoxicity give a high rate of false positive results, which makes application in the early discovery phase of drug development cumbersome. The goal of the present thesis was therefore to develop improved and new in vitro assays for detecting the genotoxic and non-genotoxic carcinogenic potential of chemicals, validate these assays with proper reference compounds, and to develop a strategy for application of these assays in the early discovery phase of drug development. High throughput assays based on bacteria, yeast and human/rodent cell lines were developed. In the case of human cell lines, the focus was on the HepG2 cell line as the properties of HepG2 cells are expected to give a good prediction for in vivo genotoxicity. The results in this thesis show that an early prediction can be made for bacterial mutagenicity (gene mutations), mammalian genotoxicity (chromosome damage), and non-genotoxic carcinogenic potential by aryl hydrocarbon receptor (AhR) activation. To develop a strategy for application of the HTS genotoxicity assays in the early discovery phase several combinations of assays were evaluated. The combination VitotoxTM + HepG2 p53 reporter assay was based on the presented results in this thesis the most useful for screening compounds for their genotoxic potential in the early drug discovery phase without the risk on high numbers of false positives. CYP1A induction assays in human HepG2 and rat H4IIE cells may be performed in parallel with these assays to be able to detect non-genotoxic carcinogenic potential by AhR activators. Further application of these assays may prove useful in future drug development strategies. <br/

Come, see and experience affective interactive art

The progress in the field of affective computing enables the realization of affective consumer products, affective games, and affective art. This paper describes the affective interactive art system Mood Swings, which interprets and visualizes affect expressed by a person. Mood Swings is founded on the integration of a framework for affective movements and a color model. This enables Mood Swings to recognize affective movement characteristics as expressed by a person and display a color that matches the expressed emotion. With that, a unique interactive system is introduced, which can be considered as art, a game, or a combination of both