41.
Anomalous Asymmetries in Flows Generated by Algorithms that Fail to Conserve Symmetry
- Y. Levy; L. Hesselink; D. Degani; Yuval Levy; Lambertus Hesselink Y; David Degani Z
Numerical simulations of high-angle-of-attack flows around slender bodies of revolution are carried out using four different numerical algorithms, a partially flux-split algorithm, the Beam and Warming algorithm in its original and diagonal forms and an algorithm combining block and diagonal forms. Comparisons of laminar flows at # # 20 # and # # 40 # reveal that the diagonal algorithm fails to conserve symmetry at high angles of attack and a spurious asymmetry is developed. The source of the spurious asymmetry has been traced, and found to be inherent to the diagonalization process.
42.
Minimize Waiting Time and Conserve Energy by Scheduling Transmissions in IEEE 802.11-based Ad Hoc Networks
- Chih-Shun Hsu; Jang-Ping Sheu; Yu-Chee Tseng
The mobile ad hoc network (MANET) has attracted lots of attention recently. Most of the researches assume that every mobile host in the MANET uses a fixed data rate and follows a distributed coordination function (DCF) to transmit messages. As we know that none of the research has combined multiple data rates and transmission scheduling to minimize waiting time and conserve energy for a MANET with powersaving (PS) mode hosts. IEEE 802.11 has already supported multiple data transmission rate. However, how to decide the transmission rate is still an open question. Here, we propose a data rate selection protocol to...
43.
GERMINAÇÃO DE SEMENTES, EMERGÊNCIA E RECRUTAMENTO DEPLÂNTULAS DE DEZ ESPÉCIES ARBÓREAS DAS VÁRZEAS DASRESERVAS DE DESENVOLVIMENTO SUSTENTÁVEL AMANÃ EMAMIRAUÁ, AMAZÔNIA CENTRAL
- Auristela dos Santos Conserva
A grande variação na dinâmica dos rios da Amazônia e de seus afluentes tem como conseqüência à formação de um mosaico, composto por sítios de idades diferentes. Tais locais estão sujeitos a variações no período de inundação, fazendo com que os organismos destas florestas necessitem desenvolver adaptações e estratégias para utilizar eficientemente as fases aquáticas e terrestres. Existe uma variedade de condições deestresse ambiental em que as espécies vegetais estão submetidas e de respostas dadas por estas. No entanto, se é possível identificar a natureza e a duração do período deestresse ambiental predominante no ambiente (e.g. período de inundação) é...
44.
Modelagem e simulação do processo de esterilização térmica em batelada de vegetais em conserva
- Fanny Ferreira Melo Fávero de Fravet
A esterilização térmica de alimentos baseia-se na aplicação de condições de temperatura porperíodos de tempo que levem à inativação de microorganismos, esporos e enzimas econseqüentemente a obtenção de produtos seguros por períodos ampliados de tempo. Nestetrabalho é proposto um modelo matemático capaz de representar a transferência de calordurante o tratamento térmico de vegetais em conserva em autoclave a vapor, horizontal, commúltiplos estágios e operação em batelada. A partir de uma metodologia teóricocomputacional,desenvolveram-se modelos parciais representativos da troca térmica no grão,lata e autoclave, com posterior acoplamento desses em um modelo global. O modelodinâmico proposto possui vários níveis de detalhamento, sendo que...
45.
Efeito da acidificação com diferentes ácidos sobre as características sensoriais e inibição do Clostridium botulinum no Palmito de Pupunha em conserva
- Maria Ruth Vieira de Lemos Vasconcelos
A porção comestível do tronco de algumas palmeiras, utilizadas para aprodução de palmito é um produto de importância para o Brasil como principalprodutor e exportador na forma em coonserva, detendo 85% da produção mundial. Aregião Nordeste tem se destacado como produtora da variedade pupunha (Bactrisgasipaes), nativa da Amazônia, que apresenta vantagens ecológicas por se tratar depalmeira cultivada, com características de perfilhamento, precocidade de produção equalidade satisfatória. A ocorrência de toxinfecções por Clostridium botulinumprovocadas pelo consumo de palmito industrializado levou o Ministério da Saúde aestabelecer a obrigatoriedade do uso de ácido associado à salmoura para produçãode palmito com o objetivo de...
46.
Minimização de afluentes e avaliação de sistema biológico de tratamento de águas residuárias em uma indústria de conservas vegetais
- Charles Soares Huber
Avaliou-se a adição de um surfactante químico à solução de hidróxido de sódio,utilizada no processo de descasque químico do pêssego. Os resultados obtidosforam comparados com o do processo tradicional, sem a adição desta substância.Observou-se reduções de 57,14% no consumo de hidróxido de sódio, 49,18% nageração de efluente líquido, no processo de lavagem da fruta e 42,81%, 16,02 %,45,45%, 24,16% e 31,82%, nas cargas da demanda química de oxigênio (DQO),demanda bioquímica de oxigênio (DBO), nitrogênio total Kjeldahl (NTK), sólidossuspensos totais (SST) e dos sólidos sedimentáveis (SS), respectivamente. Aságuas residuárias originadas no processo de industrialização da fruta devem sertratadas em uma estação...
47.
Modelagem e simulação do processo de esterilização térmica em batelada de vegetais em conserva
- Fanny Ferreira Melo Fávero de Fravet
A esterilização térmica de alimentos baseia-se na aplicação de condições de temperatura porperíodos de tempo que levem à inativação de microorganismos, esporos e enzimas econseqüentemente a obtenção de produtos seguros por períodos ampliados de tempo. Nestetrabalho é proposto um modelo matemático capaz de representar a transferência de calordurante o tratamento térmico de vegetais em conserva em autoclave a vapor, horizontal, commúltiplos estágios e operação em batelada. A partir de uma metodologia teóricocomputacional,desenvolveram-se modelos parciais representativos da troca térmica no grão,lata e autoclave, com posterior acoplamento desses em um modelo global. O modelodinâmico proposto possui vários níveis de detalhamento, sendo que...
48.
Topology control protocols to conserve energy in wireless ad hoc networks
- Ya Xu; Yutaka Mori; Deborah Estrin; John Heidemann
In wireless ad hoc networks and sensor networks, energy use is in many cases the most im-portant constraint since it corresponds directly to operational lifetime. This paper presents two topology control protocols that extend the lifetime of dense ad hoc networks while preserving con-nectivity, the ability for nodes to reach each other. Our protocols conserve energy by identifying redundant nodes and turning their radios off. Geographic Adaptive Fidelity (GAF) identifies re-dundant nodes by their physical location and a conservative estimate of radio range. Cluster-based Energy Conservation (CEC) directly observes radio connectivity to determine redundancy and so can be more aggressive...
49.
Topology control protocols to conserve energy in wireless ad hoc networks
- Ya Xu; Solomon Bien; Yutaka Mori; John Heidemann; Deborah Estrin
In wireless ad hoc networks and sensor networks, energy use is in many cases the most important constraint since it corresponds directly to operational lifetime. This paper presents two topology control protocols that extend the lifetime of dense ad hoc networks while preserving connectivity, the ability for nodes to reach each other. Our protocols conserve energy by identifying redundant nodes and turning their radios off. Geographic Adaptive Fidelity (GAF) identifies redundant nodes by their physical location and a conservative estimate of radio range. Cluster-based Energy Conservation (CEC) directly observes radio connectivity to determine redundancy and so can be more aggressive...
50.
Topology Control Protocols to Conserve Energy in Wireless Ad Hoc Networks
- Ya Xu; Solomon Bien; Yutaka Mori; John Heidemann; Deborah Estrin
In wireless ad hoc networks and sensor networks, energy use is in many cases the most important constraint since it corresponds directly to operational lifetime. This paper presents two topology control protocols that extend the lifetime of dense ad hoc networks while preserving connectivity, the ability for nodes to reach each other. Our protocols conserve energy by identifying redundant nodes and turning their radios off. Geographic Adaptive Fidelity (GAF) identifies redundant nodes by their physical location and a conservative estimate of radio range. Cluster-based Energy Conservation (CEC) directly observes radio connectivity to determine redundancy and so can be more aggressive...
51.
Multi-Symplectic Integrators: numerical schemes for Hamiltonian PDEs that conserve symplecticity
- Thomas J. Bridges; Sebastian Reich
The symplectic numerical integration of finite-dimensional Hamiltonian systems is a well established subject and has led to a deeper understanding of exisiting methods as well as to the development of new very efficient and accurate schemes, e.g., for rigid body, constrained, and molecular dynamics. The numerical integration of infinite-dimensional Hamiltonian systems or Hamiltonian PDEs is much less explored. In this paper, we suggest a new theoretical framework for generalizing symplectic numerical integrators for ODEs to Hamiltonian PDEs in R 2 : time plus one space dimension. The central idea is that symplecticity for Hamiltonian PDEs is directional: the symplectic structure...
52.
Abstract Topology Control Protocols to Conserve Energy in Wireless Ad Hoc Networks ¢¡
- Ya Xu; Yutaka Mori; Deborah Estrin; John Heidemann
In wireless ad hoc networks and sensor networks, energy use is in many cases the most important constraint since it corresponds directly to operational lifetime. This paper presents two topology control protocols that extend the lifetime of dense ad hoc networks while preserving connectivity, the ability for nodes to reach each other. Our protocols conserve energy by identifying redundant nodes and turning their radios off. Geographic Adaptive Fidelity (GAF) identifies redundant nodes by their physical location and a conservative estimate of radio range. Cluster-based Energy Conservation (CEC) directly observes radio connectivity to determine redundancy and so can be more aggressive...
53.
R&D and private investment: How to conserve indigenous fruit biodiversity of Southern Africa
- Waibel, Hermann; Wesseler, Justus; Mithöfer, Dagmar
Indigenous fruits contribute widely to rural incomes in Southern Africa but their availability is declining. A domestication program aims to increase farm-household income and conserve biodiversity through farmer-led tree planting. Planting domesticated indigenous fruit trees is an uncertain, irreversible but flexible investment. Our analysis applies the real option approach using contingent claims analysis, which allows solving the discounting problem. The article analyses (1) to what level fruit collection cost and/or (2) the necessary technical change, i.e. breeding progress, have to rise in order to render tree planting economical, using data from income portfolios of rural households in Zimbabwe. Results currently...
54.
Abstract Topology Control Protocols to Conserve Energy in Wireless Ad Hoc Networks ¢¡
- Ya Xu; Yutaka Mori; Deborah Estrin; John Heidemann
In wireless ad hoc networks and sensor networks, energy use is in many cases the most important constraint since it corresponds directly to operational lifetime. This paper presents two topology control protocols that extend the lifetime of dense ad hoc networks while preserving connectivity, the ability for nodes to reach each other. Our protocols conserve energy by identifying redundant nodes and turning their radios off. Geographic Adaptive Fidelity (GAF) identifies redundant nodes by their physical location and a conservative estimate of radio range. Cluster-based Energy Conservation (CEC) directly observes radio connectivity to determine redundancy and so can be more aggressive...
55.
Produtividade e qualidade de frutos de cultivares de pepino para conserva tipo "cornichon" no Vale do São Francisco
- Resende,Geraldo M. de; Costa,Nivaldo Duarte; Flori,José Egidio
Identificou-se as cultivares mais produtivas de pepino para conserva em um experimento, de setembro a novembro de 1996, no Campo Experimental de Bebedouro/Petrolina (PE). O delineamento experimental utilizado foi de casualizados completos, com 22 cultivares (Calypso, Eureka, Flurry, Francipak, Ginga AG-77, HE-601, HE-657, HE-671, HE-713, Imperial, Nautillus, Navigator, Panorama, Pioneiro, Premier, Prêmio, Primepak, SMR 18 Wisconsin, Supremo, Vlaspik, Vlasset e Vlasstar) e três repetições. A parcela experimental foi composta de quatro linhas de 3,0 m de comprimento, com espaçamento de 1,0 x 0,30 m. As cultivares Vlaspik (11,5 t/ha), Eureka (11,2 t/ha), Calypso (11,1 t/ha), Ginga AG-77 (10,7 t/ha), Imperial...
56.
Acúmulo e repartição da matéria seca da planta de pepino tipo conserva sob três doses de nutrientes minerais
- Espínola,Hugo Nicasio Rodríguez; Andriolo,Jerônimo Luiz; Bartz,Hardi René
Determinou-se o efeito de três doses de nutrientes minerais sobre o acúmulo e distribuição da matéria seca da planta de pepino tipo conserva, híbrido Crispina. As plantas foram cultivadas em sacolas plásticas com 4,6kg de substrato composto por uma mistura de 40% de casca de arroz e 60% de solo, no interior de uma estufa de polietileno, na primavera de 1998 e no verão de 1999. Foi empregado um delineamento experimental de blocos casualizados, com três repetições e 15 plantas por parcela. Os tratamentos foram constituídos por três níveis múltiplos de uma dose padrão de nutrientes aplicada para cada planta,...
57.
Increased Virulence and Competitive Advantage of a/? Over a/a or ?/? Offspring Conserves the Mating System of Candida albicans
- Lockhart, Shawn R.; Wu, Wei; Radke, Joshua B.; Zhao, Rui; Soll, David R.
The majority of Candida albicans strains in nature are a/? and must undergo homozygosis to a/a or ?/? to mate. Here we have used a mouse model for systemic infection to test the hypothesis that a/? strains predominate in nature because they have a competitive advantage over a/a and ?/? offspring in colonizing hosts. Single-strain injection experiments revealed that a/? strains were far more virulent than either their a/a or ?/? offspring. When equal numbers of parent a/? and offspring a/a or ?/? cells were co-injected, a/? always exhibited a competitive advantage at the time of extreme host morbidity or...
58.
Increased Virulence and Competitive Advantage of a/? Over a/a or ?/? Offspring Conserves the Mating System of Candida albicans
- Lockhart, Shawn R.; Wu, Wei; Radke, Joshua B.; Zhao, Rui; Soll, David R.
The majority of Candida albicans strains in nature are a/? and must undergo homozygosis to a/a or ?/? to mate. Here we have used a mouse model for systemic infection to test the hypothesis that a/? strains predominate in nature because they have a competitive advantage over a/a and ?/? offspring in colonizing hosts. Single-strain injection experiments revealed that a/? strains were far more virulent than either their a/a or ?/? offspring. When equal numbers of parent a/? and offspring a/a or ?/? cells were co-injected, a/? always exhibited a competitive advantage at the time of extreme host morbidity or...
59.
Economic Incentives to Conserve Wildlife on Private Lands: Analysis and Policy
- Tisdell, Clement A.
Some believe that provision of private property rights in wildlife on private land provides a powerful economic incentive for nature conservation because it enables property owners to market such wildlife or its attributes. If such marketing is profitable, private landholders will conserve the wildlife concerned and its required habitat. But land is not always most profitably used for exploitation of wildlife, and many economic values of wildlife (such as non-use economic values) cannot be marketed. The mobility of some wildlife adds to the limitations of the private-property approach. While some species may be conserved by this approach, it is suboptimal...
60.
Willingness of Sri Lankan Farmers to Pay for a Scheme to Conserve Elephants: An Empirical Analysis
- Bandara, Ranjith; Tisdell, Clem
This paper explores the feasibility of adopting an integrated economic approach to raise farmers’ tolerance of the presence of elephants on their farming lands. Responses to this approach were sought from a sample of farmers in the areas affected by human elephant conflict in the northwestern province of Sri Lanka. Results from a contingent valuation survey of their willingness to pay for a scheme to conserve elephants are also reported. Two separate logit regression analyses were undertaken to examine the factors that influence the farmers’ responses for the payment principle question and their opinions on the integrated economic approach. Although...
