New Strategies For Control Research Articles

INTELLIGENT CONTROL SOLUTIONS FOR STEAM POWER PLANTS TO BALANCE THE FLUCTUATION OF WIND ENERGY

A stable and quality-oriented energy supply in Germany is a pre-requisite for a sustainable national economy. Therefore, also for political reasons, the wind energy as a renewable energy source in onshore and off-shore wind power plants plays a more and more important role in this context. But this increase in wind power productions generates new and up to now unknown problems in the German energy system concerning energy transportation, the reduced availability of this energy for meteorological reasons and the thereby caused need for so called “Hour Reserve from conventional power plants”. Also the fluctuation in wind power production in addition to the fluctuations of the consumer power demand and the not measured production from decentralized sources are resulting in substantially high positive and negative reserve power in the conventional power plants which are up to now not well designed for these new requirements. The analysis of these new burdens for the power plants, the development of new energy services and new strategies of control and the design of new conventional power plants in respect with an optimal operation regime are the main goals of this investigation on behalf of VGB PowerTech.

Observation of Hamiltonian chaos and its control in wave–particle interaction

Wave–particle interactions are central in plasma physics. They can be studied in a traveling wave tube (TWT) to avoid intrinsic plasma noise. This led to detailed experimental analysis of the self-consistent interaction between unstable waves and an either cold or warm beam. More recently a test cold electron beam has been used to observe its non-self-consistent interaction with externally excited wave(s). The velocity distribution function of the electron beam is recorded with a trochoidal energy analyzer at the output of the TWT. An arbitrary waveform generator is used to launch a prescribed spectrum of waves along the slow wave structure (a 4 m long helix) of the TWT. The nonlinear synchronization of particles by a single wave responsible for Landau damping is observed. The resonant velocity domain associated with a single wave is also observed, as well as the transition to large scale chaos when the resonant domains of two waves and their secondary resonances overlap. This transition exhibits a ‘devil's staircase’ behavior when increasing the excitation amplitude in agreement with numerical simulation. A new strategy for control of chaos by building barriers of transport which prevent electrons from escaping from a given velocity region as well as its robustness are successfully tested. The underlying concepts extend far beyond the field of electron devices and plasma physics.

Targeting the Tick/Pathogen Interface for Developing New Anaplasmosis Vaccine Strategies

Bovine anaplasmosis is a tick-borne hemolytic disease of cattle that occurs worldwide caused by the intraerythrocytic rickettsiae Anaplasma marginale. Control measures, including use of acaricides, administration of antibiotics and vaccines, have varied with geographic location. Our research is focused on the tick-pathogen interface for development of new vaccine strategies with the goal of reducing anaplasmosis, tick infestations and the vectorial capacity of ticks. Toward this approach, we have targeted (1) development of an A. marginale cell culture system to provide a non-bovine antigen source, (2) characterization of an A. marginale adhesion protein, and (3) identification of key tick protective antigens for reduction of tick infestations. A cell culture system for propagation of A. marginale was developed and provided a non-bovine source of A. marginale vaccine antigen. The A. marginale adhesion protein, MSP1a, was characterized and use of recombinant MSP1a in vaccine formulations reduced clinical anaplasmosis and infection levels in ticks that acquired infection on immunized cattle. Most recently, we identified a tick-protective antigen, subolesin, that reduced tick infestations, as well as the vectorial capacity of ticks for acquisition and transmission of A marginale. This integrated approach to vaccine development shows promise for developing new strategies for control of bovine anaplasmosis.

Antibiotics which Target the Wolbachia Endosymbionts of Filarial Parasites: A New Strategy for Control of Filariasis and Amelioration of Pathology

Wolbachia endosymbionts of filariae are targets for the development of new antifilarial chemotherapy. Doxycycline to deplete Wolbachia from the worm has demonstrated the feasibility of this strategy and has provided a new chemotherapeutic tool. Recent research shows that depleting Wolbachia will also lessen pathology, and lessen adverse reactions to traditional antifilarial drugs.

FRACTIONAL ROBUST CONTROL TO DELAY CHANGES IN MAIN IRRIGATION CANALS

This paper proposes a new strategy for control of open irrigation canals based on fractional order controllers. A methodology is developed to design PI fractional controllers combined with Smith predictors which are robust to changes in the time delay. This method is applied to solve the effective control problem of an open irrigation canal. Simulated results of a standard PI controller, PI plus Smith predictor controller, and the controller developed in this paper are compared when applied to the dynamical model of a real irrigation canal pool.

05/00196 Co-combustion of olive cake with lignite coal in a circulating fluidized bed: Atimtay, A. T. et al. Fuel, 2004, 83, (7–8), 859–867

A stable and quality-oriented energy supply in Germany is a pre-requisite for a sustainable national economy. Therefore, also for political reasons, the wind energy as a renewable energy source in onshore and off-shore wind power plants plays a more and more important role in this context. But this increase in wind power productions generates new and up to now unknown problems in the German energy system concerning energy transportation, the reduced availability of this energy for meteorological reasons and the thereby caused need for so called “Hour Reserve from conventional power plants”. Also the fluctuation in wind power production in addition to the fluctuations of the consumer power demand and the not measured production from decentralized sources are resulting in substantially high positive and negative reserve power in the conventional power plants which are up to now not well designed for these new requirements. The analysis of these new burdens for the power plants, the development of new energy services and new strategies of control and the design of new conventional power plants in respect with an optimal operation regime are the main goals of this investigation on behalf of VGB PowerTech.

Control of the Copolymer Composition in Suspension Copolymerization Reactions

A new strategy for control of the copolymer composition is proposed for suspension copolymerizations. The control strategy assumes that one of the monomers is soluble in the continuous (aqueous) phase, as in the case of vinyl acetate (VAc)/acrylic acid (AA) copolymerizations. First, a hypothetical suspension copolymerization reaction is studied through simulation in order to illustrate the main features of the proposed control scheme. Then, the control strategy is implemented experimentally for actual control of the copolymer composition during VAc/AA suspension copolymerizations. The strategy is based on a detailed model developed to describe the process behavior and the AA partitioning between the organic phase and the aqueous phase, which is a fundamental point for the successful description of both conversion and copolymer composition. The proposed model was used to design monomer feed rate profiles in order to keep the copolymer composition constant throughout the batch. It is shown that the proposed control procedure is indeed able to keep the copolymer composition constant throughout the batch, despite the huge differences of reactivity between the monomer species.

Genetic basis of neonatal methicillin-resistant Staphylococcus aureus in Japan.

Methicillin-resistant Staphylococcus aureus (MRSA) is still one of major problems of drug-resistant microorganisms and healthcare-acquired infections. Methicillin-resistant Staphylococcus aureus is highly prevalent in patients in neonatal intensive care units (NICU) in Japan. The most predominant MRSA in NICU is multidrug resistant and produces superantigenic exotoxin, toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxin C (SEC). These predominant MRSA strains belong to coagulase type II, SCCmec type II, mecA-Tn554 polymorph type I-A and show closely related pulse field gel electrophoresis types. The dissemination of MRSA is wide, and there is a pandemic distribution of a single MRSA clone in the NICU of Japan. Since 1992, the nationwide spread of this clone has also led to the development of a new neonatal disease known as neonatal toxic shock-like exanthematous disease (NTED), which is caused by overactivation of vbeta2+ T cells induced by TSST-1. The spread of MRSA in NICU in Japan has been attributed to overcrowding, high rates of extremely low birthweight babies, understaffing, low control measures of infection and overuse of antibiotics. The environment of NICU and infection control intervention should be improved and a new strategy for control like vaccination or probiotics is required.

China's Changing of the Guard: Threats to Party Supremacy

����� �� With the Chinese Communist Party (CCP) having emerged from its Sixteenth Party Congress in November 2002 with a new leadership and an updated program, what is the outlook for the political system that it controls? The ease with which the recent turnover of power was handled bespeaks an unprecedented degree of institutional stability within China’s political elite. And yet the CCP has for some time now been watching its grassroots organizational strength ebb away, the victim of a number of stresses that have been generated by the Party’s progressive integration with a rapidly changing society. The CCP’s policies of “reform and opening” have meanwhile had unintended consequences that have further weakened the prospects for its continued political monopoly: Due to an expanding private sector, the Party no longer controls where people live and work; due to the spread of internet access, satellite television, and alternative media, it no longer controls what information people have or how it is disseminated; and due to a combination of larger disposable incomes and political liberalization, it no longer controls what people do with their spare time. To manage these consequences, the Party has adopted a new strategy of control. As necessary as this strategy has been, it has effectively reoriented the Party relative to Chinese society, and in a way that raises a question of long-term survival common to many a liberalizing authoritarian regime dominated by a single party: Will adapting to a new economic and social environment strengthen or actually weaken the Party’s hold on power? Bruce J. Dickson is associate professor of political science and international affairs at George Washington University. He is the author of Red Capitalists in China: The Party, Private Entrepreneurs, and Prospects for Political Change (2003) and Democratization in China and Taiwan: The Adaptability of Leninist Parties (1997), and is associate editor of the journal Problems of Post-Communism.

Bancroftian filariasis: the spatial representation of social inequality

Lymphatic filariasis is considered as a major health problem in the world. There are 1.2 billion people that live in endemic areas. At least 120 million of these people are infected. In Brazil, the cities of Recife, Maceio, and Belem, with 49 thousand infected. New strategies of control made lymphatic filariasis a disease that could be eliminated. The environment risk indicator is one of the most important planning tools in the fight against its diffusion. The aim of this dissertation is to study the occurrence of the microfilaremia in the district of Cavaleiro in Jaboatao dos Guararapes – estate of Pernambuco – and its relation with socio economic indicators. The study will be also useful in identifying risk areas in that district, by the way of building a Synthetic Environmental Indicator. The district was subdivided in 22 sub-areas and 9,520 people were examined, 213 were microfilaremic (2.2% prevalence). There were positive cases in 17 of the 22 sub-areas. Circa 73% of the cases were found in the areas that show the larger risk indicator. This demonstrates the importance of the Synthetic Indicator as a planning tool to cope with the problem of lymphatic filariasis in a spatial perspective.

Research on highly reliable solid-state lithium batteries in NIRIM

A stable and quality-oriented energy supply in Germany is a pre-requisite for a sustainable national economy. Therefore, also for political reasons, the wind energy as a renewable energy source in onshore and off-shore wind power plants plays a more and more important role in this context. But this increase in wind power productions generates new and up to now unknown problems in the German energy system concerning energy transportation, the reduced availability of this energy for meteorological reasons and the thereby caused need for so called “Hour Reserve from conventional power plants”. Also the fluctuation in wind power production in addition to the fluctuations of the consumer power demand and the not measured production from decentralized sources are resulting in substantially high positive and negative reserve power in the conventional power plants which are up to now not well designed for these new requirements. The analysis of these new burdens for the power plants, the development of new energy services and new strategies of control and the design of new conventional power plants in respect with an optimal operation regime are the main goals of this investigation on behalf of VGB PowerTech.

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In order to develop a new strategy for control of B. paupera, a serious pest insect in production of mushroom, Agaricus bisporus the mating behavior and related regulatory factors were elucidated in laboratory experiments. Mating behavior was analyzed by observation of 75 pairs of cultured flies. The typical mating sequence was: 1) beginning of male intermittent wing fanning (WF), 2) walking in a zigzag approach (ZA) while continuing WF, 3) abdominal curling (AC) forward beneath the thorax while opening claspers to grab female abdomen when near the female, 4) pivoting 180 degrees around body axis (P180), 5) mating occurrence (MO). This sequence was very stereotypical whereas the females exhibited no characteristic synchronous actions. Mated females refused copulation with subsequent male copulation attempts by kicking the male off with the hind legs or escaping the males mating attempts. Bioassay results demonstrated that a female produced volatile sex pheromone evokes typical male copulating behavior. The threshold activity of the crude female extract eliciting WF and ZA in males was shown to be 2×10−3 female equivalents (FE) in the tube assay. Attractive activity of female extract was corroborated in wind tunnel assays. Male flies showed WF, ZA, and AC responses to all parts of the female body. Effects of female age on male responsiveness to pheromones seemed non-critical, because males demonstrated all responses (WF, ZA, AC) whenever exposed to females from the teneral period to 3 days after emergence. Males responded to melanized pupae with WF and ZA. In male flies, sexual responses began 30 min after adult eclosion, and increased to a maximum 2 h after emergence.

Lactoferrin Peptide Increases the Survival of Candida albicans - Inoculated Mice by Upregulating Neutrophil and Macrophage Functions, Especially in Combination with Amphotericin B and Granulocyte-Macrophage Colony-Stimulating Factor

To develop a new strategy to control candidiasis, we examined in vivo the anticandidal effects of a synthetic lactoferrin peptide, FKCRRWQWRM (peptide 2) and the peptide that mimics it, FKARRWQWRM (peptide 2'). Although all mice that underwent intraperitoneal injection of 5 x 10(8) Candida cells with or without peptide 2' died within 8 or 7 days, respectively, the survival times of mice treated with 5 to 100 microg of intravenous peptide 2 per day for 5 days after the candidal inoculation were prolonged between 8.4 +/- 2.9 and 22.4 +/- 3.6 days, depending on the dose of peptide 2. The prolongation of survival by peptide 2 was also observed in mice that were infected with 1.0 x 10(9) Candida albicans cells (3.2 +/- 1.3 days in control mice versus 8.2 +/- 2.4 days in the mice injected with 10 microg of peptide 2 per day). In the high-dose inoculation, a combination of peptide 2 (10 microg/day) with amphotericin B (0.1 microg/day) and granulocyte-macrophage colony-stimulating factor (GM-CSF) (0.1 microg/day) brought prolonged survival. With a combination of these agents, 60% of the mice were alive for more than 22 days. Correspondingly, peptide 2 activated phagocytes inducing inducible NO synthase and the expression of p47(phox) and p67(phox), and peptide 2 increased phagocyte Candida-killing activities up to 1.5-fold of the control levels upregulating the generation of superoxide, lactoferrin, and defensin from neutrophils and macrophages. These findings indicated that the anticandidal effects of peptide 2 depend not only on the direct Candida cell growth-inhibitory activity, but also on the phagocytes' upregulatory activity, and that combinations of peptide 2 with GM-CSF and antifungal drugs will help in the development of new strategies for control of candidiasis.

Transmission blocking vaccine studies in leishmaniasis: I. Lipophosphoglycan is a promising transmission blocking vaccine molecule against cutaneous leishmaniasis.

New strategies for control of leishmaniasis is needed as chemotherapy using antimonial drugs is prolonged, expensive, associated with side effects and relapses. Vector control has limitations and a vaccine which may be the best approach is not available. To assess the level of inhibition of promastigote development and gut morphology in infected Phlebotomus duboscqi sandflies fed on different groups of BALB/c mice immunised with rgp63, lipophosglycan (LPG) or their cocktail and whole parasite antigens prepared from L. major culture-derived promastigotes. BALB/c mice were immunised adequately with Leishmania major-derived antigens namely, crude whole parasite (WPA), recombinant 63 kilodalton glycoprotein (rgp63), LPG and a cocktail composed of rgp63 plus LPG antigens. Laboratory reared Phlebotomus duboscqi sandflies, the natural vector for L. major were later allowed to feed on immunised animals, interrupted and allowed to continue feeding on infected animals for an equal amount of time until they became fully engorged. The sandflies were maintained on apples as a carbohydrate source in an insectary maintained at a temperature of 25 degrees C and 80% relative humidity. Some of the sandflies were dissected on days 2, 4 and 6 after feeding and observed using the light and the transmission electron microscopy for any changes in their gut morphology. The remaining sandflies were all dissected on the sixth day post-feeding and examined for procyclics, nectomonads, haptomonads and metacyclic promastigote forms of Leishmania. Sandflies which had previously fed on WPA, LPG plus rgp63 cocktail and LPG-immunised mice showed the lowest infection rates compared to control sandflies fed on saline immunised mice (p < 0.05). A significant number of procyclic promastigotes, the first developmental form of the parasite in culture as well as in the sandfly was observed in sandflies which fed on LPG-immunised mice (p < 0.05). The dominant parasite form in sandflies which fed on rgp63 or LPG-immunised mice was the nectomonad form but very few of the infective metacyclic forms (p < 0.05). Control sandflies fed on saline immunised or infected mice alone displayed a normal pattern of parasite development up to the metacyclic stage. Studies showed that two possible mechanisms through which immune sera from immunised mice may cause inhibition of parasite development is by exflagellation of nectomonad forms and degeneration of the sandfly midgut epithelium as revealed by light and electron microscopy studies respectively. This study has shown that immune-mediated transmission blocking may be applied to Leishmania infections. Based on observation of the procyclic promastigotes, the dominance of the nectomonad forms, low infectivity rates in sandflies fed on LPG-immunised mice, we concluded that LPG stands out to be a promising transmission blocking vaccine candidate in leishmaniasis.

The microbiology of periodontal disease.

Periodontal disease result from mixed bacterial infections, in which both host resistance barriers and bacterial interactions are important. Approximately ten bacterial species are strongly implicated with various forms of periodontal disease, although species that cannot yet be cultivated are likely also to be relevant. New technologies have shown that pathogenic bacterial species are present in defined complexes within subgingival plaque, thus identifying specific targets for therapeutic intervention. In light of increasing antibiotic resistance amongst oral bacteria, new strategies for control of periodontal bacterial complexes must be developed that inhibit the bacterial factors necessary for colonization and destruction of host tissues.

Strategies to interrupt the development of Anaplasma marginale in its tick vector. The effect of bovine-derived antibodies.

Anaplasma marginale is a rickettsia transmitted by ticks that invades and multiplies in bovine erythrocytes causing the disease anaplasmosis. A complex developmental cycle occurs within ticks that begins in midgut cells, with subsequent infection in gut muscle cells. Final development occurs in salivary glands from where the rickettsia is transmitted to the vertebrate host. At each site of development, A. marginale multiplies within membrane-bound inclusions. Attempts to control anaplasmosis have focused on cattle and have included immunization and prophylactic treatment with tetracyclines. New strategies for control of anaplasmosis are being focused on the tick vector. Development of vaccines against hemoparasites in ticks may be feasible because vertebrate host immunoglobulins appear to cross the midgut epithelium of invertebrates and enter the hemolymph without breakdown. We tested the effect of A. marginale antibodies ingested by ticks with the bloodmeal on infections in ticks. Cattle were immunized with purified outer membrane proteins of erythrocytic-derived parasites. Infections in ticks exposed to the immunized cattle were determined using an Anaplasma-specific DNA probe, light and electron microscopy, and tick transmission studies. Vaccine-derived antibodies did not appear to affect the development and transmission of A. marginale in ticks. Further studies are needed to determine if bovine antibodies remain intact within ticks and whether the tick stage of A. marginale has unique surface antigens from the erythrocytic stage.

Barrier spraying to control the malaria vector Anopheles albimanus: laboratory and field evaluation in the Dominican Republic

To develop a new strategy for control of exophilic/exophagic malaria vectors which rest on peridomestic foliage, Anopheles albimanus was used for laboratory bioassays of mosquito adulticides applied to various vegetation types. Of the three classes of insecticide tested, the pyrethroid (permethrin at 112 g/ha) showed greater foliar persistence than either the carbamate (bendiocarb at 340 g/ha) or the organophosphorus compound (malathion at 277 g/ha). Field evaluation of barrier spraying against An.albimanus was evaluated in rural villages of southwest Dominican Republic during 1989. The pyrethroid deltamethrin was sprayed aerially for ultra-low volume application at treatment rates of 17-19 g a.i./ha in a radius of 500 m around two villages. An.albimanus were monitored by light-traps and human bait collections at both treated villages, compared with two similar untreated villages, up to 9 nights posttreatment. Densities of female An.albimanus were significantly reduced in the sprayed villages for at least 8 or 9 nights. Further evaluation of barrier spraying is recommended to determine optimal pyrethroid formulations and applications rates, their impact on non-target fauna and efficacy against malaria transmission.

Recent advances in detection and control of infectious hematopoietic necrosis virus in aquaculture

Infectious hematopoietic necrosis (IHN) is one of the most important viral diseases of salmon and trout reared in culture. The disease remains untreatable with avoidance being the only control measure. Much has been learned about the chemical, physical, and serological characteristics of the rhabdovirus causing IHN, but critical gaps exist in our understanding of the biology of the virus in nature. The tools of molecular biology have provided improved methods for detection of pathogens and new strategies for control of viral diseases. This paper reviews several recent improvements in methods for detecting infectious hematopoietic necrosis virus including the application of enzyme-linked immunosorbent assays, development of monoclonal antibodies and DNA probes, and use of the polymerase chain reaction. New strategies for control of IHN through the use of better water treatment, more resistant fish, antiviral drugs or chemicals, and new generation vaccines are discussed.

Nontypeable bacteriophage patterns of methicillin-resistant Staphylococcus aureus involved in a hospital outbreak

Of 93 strains of Staphylococcus aureus isolated from inpatient wards of Ismailia General Hospital, 48 (51%) were proven to be methicillin resistant (MR). Of these MR S. aureus strains, 44 were isolated from patients and 4 were isolated from healthy carriers, who were newly arrived interns working in the same wards. Bacteriophage patterns of MR S. aureus were identified by using routine test dilution (RTD) and 100-fold dilutions (100 RTD) of phages. Of these 48 strains, 37 (75%) (33 from patients and 4 from interns) were nontypeable when using RTD and 100 RTD of phages. Of the other 11 strains, 8 were nontypeable by RTD of phages, but 5 of them had the phage pattern D11/1136 when tested by 100 RTD. Three strains had the phage pattern 3A/3C/55/71, and three strains had different phage patterns, 29/81, 96, and 95/D11. The finding of colonization with virulent MR S. aureus strains in interns working on the wards in which these patients were located suggested that new strategies for control of MR S. aureus nosocomial infections must be considered and evaluated.

Transformation ofAspergillus flavus to study aflatoxin biosynthesis

Aflatoxin contamination of agricultural commodities continues to be a serious problem in the United States. Breeding for resistant genotypes has been unsuccessful and detoxification of food sources is not economically feasible. New strategies for control may become apparent once more is known about the biosynthesis and regulation of aflatoxin. Although the biosynthetic pathway of aflatoxin has been extensively studied, little is known about the regulation of the individual steps in the pathway. We have developed a genetic transformation system for Aspergillus flavus that provides a new and expedient approach to studying the biosynthesis of aflatoxin and its regulation. Through the use of this genetic transformation system, genes for aflatoxin biosynthesis can be identified and isolated by the complementation of aflatoxin negative mutants. In this paper we discuss molecular strategies for studying the regulation and biosynthesis of aflatoxin.