The Experts below are selected from a list of 263838 Experts worldwide ranked by ideXlab platform
T. Noren - One of the best experts on this subject based on the ideXlab platform.
-
Modeling and control of a novel heat exchange reactor, the Open Plate Reactor
Control Engineering Practice, 2007Co-Authors: Staffan Haugwitz, Per Hagander, T. NorenAbstract:A new chemical reactor, the Open Plate Reactor, is being developed by Alfa Laval AB. It combines good mixing with high heat transfer capacity into one operation. With the new concept, highly exothermic reactions can be produced using more concentrated reactants. A nonlinear model of the reactor is derived and a control system is developed. For temperature control a cooling system is designed and experimentally verified, which uses a mid-ranging control structure to increase the operating range of the hydraulic equipment. A Model Predictive Controller is proposed to maximize the conversion under hard input and state constraints. An extended Kalman filter is designed to estimate unmeasured concentrations and parameters. Simulations show that the designed control system gives high conversion and ensures that the temperature inside the reactor does not exceed a pre-defined safety limit.
Murray B. Isman - One of the best experts on this subject based on the ideXlab platform.
-
Influence of foliar glucosinolates in oilseed rape and mustard on feeding and growth of the bertha armyworm,Mamestra configurata Walker
Journal of Chemical Ecology, 1993Co-Authors: Catherine Mccloskey, Murray B. IsmanAbstract:The relationship between host plant glucosinolate profile and feeding and growth of the Bertha armyworm, Mamestra configurata Walker was investigated using eight cultivated rape and mustard varieties. Mean larval weights of neonates reared on intact rosette-stage plants were significantly different on the different species in the order Brassica juncea < Sinapis alba < B. napus < B. campestris . While B. juncea was least preferred, S. alba was significantly more attractive to neonate larvae in choice tests. Relative consumption and growth rates of fourth-instar larvae were also reduced on B. juncea foliage. Other differences were dependent on the plant growth stage. Neonate preference was not correlated to total glucosinolate levels, but rather to the concentrations of isothiocyanate-releasing glucosinolates. However, the relationship between consumption and glucosinolate levels was inconsistent. Relative growth rate was negatively correlated to total glucosinolate content for stage 3 and 4 foliage—mainly due to the concentration of isothiocyanatereleasing glucosinolates. The relative importance of isothiocyanate-releasing glucosinolates was verified by rearing neonates on meridic diets containing equimolar concentrations of sinigrin, its metabolite, allyl isothiocyanate, and indole-3-carbinol, metabolite of 3-indolylmethyl glucosinolate. Sinigrin and allyl isothiocyanate in the diet produced virtually identical negative weight vs. concentration regression lines. No such dose-response effect was observed with indole-3-carbinol. The data suggest that foliar isothiocyanate-releasing glucosinolates may provide some degree of plant protection from polyphagous insects.
Staffan Haugwitz - One of the best experts on this subject based on the ideXlab platform.
-
Modeling and control of a novel heat exchange reactor, the Open Plate Reactor
Control Engineering Practice, 2007Co-Authors: Staffan Haugwitz, Per Hagander, T. NorenAbstract:A new chemical reactor, the Open Plate Reactor, is being developed by Alfa Laval AB. It combines good mixing with high heat transfer capacity into one operation. With the new concept, highly exothermic reactions can be produced using more concentrated reactants. A nonlinear model of the reactor is derived and a control system is developed. For temperature control a cooling system is designed and experimentally verified, which uses a mid-ranging control structure to increase the operating range of the hydraulic equipment. A Model Predictive Controller is proposed to maximize the conversion under hard input and state constraints. An extended Kalman filter is designed to estimate unmeasured concentrations and parameters. Simulations show that the designed control system gives high conversion and ensures that the temperature inside the reactor does not exceed a pre-defined safety limit.
Catherine Mccloskey - One of the best experts on this subject based on the ideXlab platform.
-
Influence of foliar glucosinolates in oilseed rape and mustard on feeding and growth of the bertha armyworm,Mamestra configurata Walker
Journal of Chemical Ecology, 1993Co-Authors: Catherine Mccloskey, Murray B. IsmanAbstract:The relationship between host plant glucosinolate profile and feeding and growth of the Bertha armyworm, Mamestra configurata Walker was investigated using eight cultivated rape and mustard varieties. Mean larval weights of neonates reared on intact rosette-stage plants were significantly different on the different species in the order Brassica juncea < Sinapis alba < B. napus < B. campestris . While B. juncea was least preferred, S. alba was significantly more attractive to neonate larvae in choice tests. Relative consumption and growth rates of fourth-instar larvae were also reduced on B. juncea foliage. Other differences were dependent on the plant growth stage. Neonate preference was not correlated to total glucosinolate levels, but rather to the concentrations of isothiocyanate-releasing glucosinolates. However, the relationship between consumption and glucosinolate levels was inconsistent. Relative growth rate was negatively correlated to total glucosinolate content for stage 3 and 4 foliage—mainly due to the concentration of isothiocyanatereleasing glucosinolates. The relative importance of isothiocyanate-releasing glucosinolates was verified by rearing neonates on meridic diets containing equimolar concentrations of sinigrin, its metabolite, allyl isothiocyanate, and indole-3-carbinol, metabolite of 3-indolylmethyl glucosinolate. Sinigrin and allyl isothiocyanate in the diet produced virtually identical negative weight vs. concentration regression lines. No such dose-response effect was observed with indole-3-carbinol. The data suggest that foliar isothiocyanate-releasing glucosinolates may provide some degree of plant protection from polyphagous insects.
Caroline Müller - One of the best experts on this subject based on the ideXlab platform.
-
larval performance of the mustard leaf beetle phaedon cochleariae coleoptera chrysomelidae on white mustard sinapis alba and watercress nasturtium officinale leaves in dependence of plant exposure to ultraviolet radiation
Environmental Pollution, 2009Co-Authors: Kerstin Reifenrath, Caroline MüllerAbstract:Short-term exposure to ambient or attenuated ultraviolet (UV) radiation resulted in shifts in plant metabolite concentrations of the Brassicaceae Sinapis alba and Nasturtium officinale. Leaf quality also varied between plant species and within species due to age. Larvae of the oligophagous leaf beetle Phaedon cochleariae were raised on these different host leaves, in order to investigate the effects of variable plant chemistry on this herbivore. The performance of P. cochleariae was influenced by chemical differences between and within plant species but it responded with high plasticity to plants stressed by ultraviolet radiation. Body mass increase and developmental times of larvae were exclusively affected by plant species and leaf-age. However, developmental differences were fully compensated in the pupal stage. We suggest that the plasticity of herbivores may depend on the degree of specialisation, and insect performance may not necessarily be altered by stress-induced host plants.
-
lack of sequestration of host plant glucosinolates in pieris rapae and p grarricae
Chemoecology, 2003Co-Authors: Caroline Müller, Niels Agerbirk, Carl Erik OlsenAbstract:Sequestration of plant toxins in herbivores is often correlated with aposematic coloration and gregarious behaviour. Larvae of Pieris brassicae show these conspicuous morphological and behavioural characteristics and were thus suggested to sequester glucosinolates that are characteristic secondary metabolites of their host plants. P. rapaeare camouflaged and solitary, and are thus not expected to sequester. To test this hypothesis and to check the repeatabi-lity of a study that did report the presence of the glucosinolate sinigrin in P. brassicae, larvae were reared on three species of Brassicaceae (Sinapis alba, Brassica nigra and Barbarea stricta), and different leaf and insect samples were taken for glucosinolate analysis. The major host plant glucosinolates could only be found in traces or not at all in larval haemolymph, bled or starved larvae, faeces or pupae of both species or P. brassicae regurgitant. Haemolymph of both Pieris spp. was not rejected by the ant Myrmica rubra in dual-choice assays; the regurgitant of P. brassicae was rejected. This suggests the presence of compounds other than glucosinolates that might be sequestered in or produced by P. brassicae only. In faeces of both Pieris spp. a compound which yielded 4-hydroxybenzylcyanide (HBC) upon incubation with sulfatase was detected in high concentrations when larvae had been reared on S. alba. This compound may be derived from hydrolysis of sinalbin, the main glucosinolate of that plant. The unidentified HBC progenitor was apparently not sequestered in the two Pieris spp., and was not detected in faeces of larvae reared on B. nigra or B. stricta.
-
sequestration of host plant glucosinolates in the defensive hemolymph of the sawfly athalia rosae
Journal of Chemical Ecology, 2001Co-Authors: Caroline Müller, Carl Erik Olsen, Niels Agerbirk, Jeanluc Boeve, Urs Schaffner, Paul M BrakefieldAbstract:Interactions between insects and glucosinolate-containing plant species have been investigated for a long time. Although the glucosinolate–myrosinase system is believed to act as a defense mechanism against generalist herbivores and fungi, several specialist insects use these secondary metabolites for host plant finding and acceptance and can handle them physiologically. However, sequestration of glucosinolates in specialist herbivores has been less well studied. Larvae of the turnip sawfly Athalia rosae feed on several glucosinolate-containing plant species. When larvae are disturbed by antagonists, they release one or more small droplets of hemolymph from their integument. This “reflex bleeding” is used as a defense mechanism. Specific glucosinolate analysis, by conversion to desulfoglucosinolates and analysis of these by high-performance liquid chromatography coupled to diode array UV spectroscopy and mass spectrometry, revealed that larvae incorporate and concentrate the plant's characteristic glucosinolates from their hosts. Extracts of larvae that were reared on Sinapis alba contained sinalbin, even when the larvae were first starved for 22 hr and, thus, had empty guts. Hemolymph was analyzed from larvae that were reared on either S. alba, Brassica nigra, or Barbarea stricta. Leaves were analyzed from the same plants the larvae had fed on. Sinalbin (from S. alba), sinigrin (B. nigra), or glucobarbarin and glucobrassicin (B. stricta) were present in leaves in concentrations less than 1 μmol/g fresh weight, while the same glucosinolates could be detected in the larvae's hemolymph in concentrations between 10 and 31 μmol/g fresh weight, except that glucobrassicin was present only as a trace. In larval feces, only trace amounts of glucosinolates (sinalbin and sinigrin) could be detected. The glucosinolates were likewise found in freshly emerged adults, showing that the sequestered phytochemicals were transferred through the pupal stage.