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Search Results: 1 - 10 of 2893 matches for " Harry Edmar;Lombardi "
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Usable work of macro-scale cavities in liquids
Schulz, Harry Edmar;Lombardi, Geraldo;Nascimento, Francisco Júlio do;Trebi, Hélio José Donizeti;Santos, Jorge Nicolau dos;Sim?es, André Luiz Andrade;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2012, DOI: 10.1590/S1678-58782012000400008
Abstract: it is shown that the generation of cavities in a liquid can produce usable work, which is illustrated by the stretching of a string. this work is done during the expansion of the cavity, and not with its collapse. basic equations are presented for the movement of a device moved by the so called cavity events. a theoretical solution is also proposed, which uses polynomial functions relating the so called "excess of pressure" in the cavity and time. evaluations of the force generated during the expansion of the cavity showed a mean peak value of about 58 n for the moving container, while measurements with the container fixed to a support showed a peak value of 476 n, considered somewhat overestimated, because high frequency oscillations seem to superpose the mean behavior. simultaneous phenomena occurring during the cavity events are also described. series of pictures of the experiments are presented.
Da Silva,Alexandre Marco; Edmar Schulz,Harry;
Interciencia , 2001,
Abstract: in this paper the c factor of the universal soil loss equation was estimated for a mulch of yard debris, disposed on the surface of sandy red yellow latossol (hapludox - oxisol). the experiment was conducted at the city of itirapina, state of s?o paulo, brazil, during the heavy rain period from january 1st to march 31st, 1996. the value of the c factor estimated for that period was 0.075. the material presented satisfactory effectiveness to control soil erosion. further studies are needed to evaluate the combined effect of this mulch as soil erosion controlling material and organic fertilizer.
Transferência de massa gás-líquido em coluna de aera??o
Salla, Marcio Ricardo;Schulz, Harry Edmar;
Engenharia Sanitaria e Ambiental , 2008, DOI: 10.1590/S1413-41522008000200009
Abstract: the present work is a study of the mass transfer gas-liquid from air bubbles into water, generated by a diffuser of air, in a column of aeration, changing the air flow from 400 l/h to 2000 l/h, the level of water from 0.50 m to 1.80 m, whose taxes of superficial application of air had varied of 3.1 l/m2.s to 15.4 l/m2.s. several hydrodynamics characteristics were measured, such as the velocity range of the air bubbles and their diameter, fundamental to check the mass transfer coefficient that are in literature, by using a laser equipment for non-intrusive velocimetry. after of the study of the mass transfer, it was concluded that the air flow between 400 l/h and 800 l/h and the level of water of 1.80 m was the most efficient of mass transfer, guaranteeing for these measure, into of the column in study, most quantity of dissolved oxygen.
Hydrosedimentological dynamic on água Fria Watershed
Silva, Alexandre Marco da;Schulz, Harry Edmar;
Brazilian Archives of Biology and Technology , 2007, DOI: 10.1590/S1516-89132007000500014
Abstract: this study aimed surveying the amount of sediment yielded from the água fria watershed (palmas, tocantins, brazil), from february-1998 to january-1999, and investigating the relations between the sediment yield and some environmental and/or antropic factors. the colby's method was the technique employed for this investigation. the specific sediment yield and sediment delivery ratio were also determined for this period. it was estimated that 138,619 tons of sediment were yielded and the specific sediment yield for the study area was 827 t km-2 y-1, while the sediment delivery ratio was 6.2%. the suspended load was the most dominating fraction in almost all the studied period.
Spatial and temporal characterization of some water quality physical parameters and their relationships with land-use in água Fria watershed (Palmas – TO, Brazil)
Alexandre Marco Silva,Harry Edmar Schulz
Ambiente e água : An Interdisciplinary Journal of Applied Science , 2007,
Abstract: Due to a high population growth that has been occurring in Palmas and due to land use changes that are caused by this population growth and development, the goal of this paper was to study the behavior of four physical parameters of water quality of the água Fria watershed. The parameters were turbidity, total suspended solids, settleable solids and total dissolved solids. Eight gauging stations were established and the water samples were monthly collected from February/1998 to February/1999. The water bodies of the watershed were generally in good condition concerning these four parameters. However, there were some cases of seasonal irregularity of some parameters, as well as no correlation among some of studied parameters. This might be an indicator of some impacts like accelerated erosion due to a misuse of the lands and misuse of local water resources.
Medidas da concentra??o de oxigênio dissolvido na superfície da água
Janzen, Johannes Gerson;Schulz, Harry Edmar;Lamon, Ant?nio Wagner;
Engenharia Sanitaria e Ambiental , 2008, DOI: 10.1590/S1413-41522008000300006
Abstract: gas transfer across the air-water interface is an important process for large-scale climate cycles as well as smaller environmental systems such as rivers, lakes, streams, and wastewater treatment basins. to improve the understanding of the basic principles involved in this phenomenon it is necessary to use suitable apparatus and experimental techniques. in this study, a microprobe has been used for measurements of oxygen concentration in an oscillating-grid tank. the microprobe has tip dimensions of the order of a few microns. the results demonstrate that it is feasible to measure, under controlled turbulence conditions that are representative for environmental situations, the fluctuating oxygen concentrations that take place in a boundary layer below the air-water interface.
Simula??o da intera??o entre águas subterraneas e superficiais no aqüífero barreiras na regi?o da Lagoa do Bonfim por elementos analíticos
Batista, José Anderson do N.;Wendland, Edson;Schulz, Harry Edmar;
Revista Brasileira de Geofísica , 2007, DOI: 10.1590/S0102-261X2007000200001
Abstract: in rio grande do norte state, barreiras aquifer is the most important groundwater reservoir. in local water resources planning it is estimated for year 2020 a rise of 35% in withdraws from that aquifer. in this sense, groundwater flow in bonfim lake area has been hardly studied in order to evaluate how groundwater pumping interacts to surface water. the main objective in this work is to contribute to groundwater flow knowledge in the area and secondly to demonstrate the analytic element method (aem) functionality in strait (or elongated) aquifers by coupling the method of images. the proposed method allows the simulation to be extended infinitely between two straight lines. however, the results nearest regional boundaries become insensitive to the boundary shape. thus, the simulation produced a recharge rate estimate about 0.9 mm/day. the groundwater pumping moves the bonfim lake water level approximately to 5.0 m below.
Moving beds represented by immersed boundaries: numerical experiments using large eddy simulation
Alamy Filho,José Eduardo; Edmar Schulz,Harry; Andrade Sim?es,André Luiz;
Ingeniare. Revista chilena de ingeniería , 2012, DOI: 10.4067/S0718-33052012000300010
Abstract: the immerse boundary method (ibm) was used to evaluate the sediment transport over deformable beds. large eddy simulation (les) procedures were used for the mathematical treatment of turbulence, and the advection-diffusion equation was used to calculate sediment concentration. the finite differences method with staggered grid was applied for the numerical solution of the governing equations (filtered navier-stokes, continuity and advection-diffusion equations). spatial derivatives were discretized using second order centered differences. a second order explicit adams-bashforth scheme was used for the time evolution in the advection-diffusion equation, while a fourth order adams-bashforth scheme was used for the filtered navier-stokes equations. the numerical simulation reproduced flow structures like large eddies after the dune crests and counter-rotative vortices, which are important in sediment transport. resuspension fluxes and sedimentation (dependent on particle concentration) were calculated using equations proposed in this study. the deformations of the bed caused by erosion and deposition may be well followed through the present procedures, showing that this methodology is adequate to evaluate bed modifications and sediment transport in alluvial flows.
Salla,Marcio Ricardo; Vieira Soares,Leonardo; Alamy Filho,José Eduardo; Daniel,Luiz Antonio; Schulz,Harry Edmar;
Ingeniare. Revista chilena de ingeniería , 2008, DOI: 10.4067/S0718-33052008000300008
Abstract: the size of the cross section of an ozonization column influences its hydrodynamic characteristics, which, on its turn, has effects on phenomena that depend on the relative movement between gas bubbles and liquid. to observe the influence of the cross sectional area on gas concentration and bubbles velocity, two columns were used. the first column had a square cross section with side of 0.19m and the second had a circular cross section with diameter of 0.10 m. the ascendant velocities of the bubbles and their concentration were measured in both columns and compared. the transversal spread of the plumes of bubbles was also quantified. the results show that the increase of the cross section of the column, in the proportion studied here, does not result in a similar increase of the cross section of the ascending plume of bubbles. furthermore, the results of average velocities and concentrations obtained for the smallest cross section resulted independent of the liquid level in the column, while the results for the largest cross section showed to be dependent of this level. the ratio between the cross sectional areas of the larger and the smaller plumes of bubbles decreases for higher distances to the bottom of the columns.
Lix?es inativos na regi?o carbonífera de Santa Catarina: análise dos riscos à saúde pública e ao meio ambiente
Possamai,Fernando Pagani; Viana,Ednilson; Schulz,Harry Edmar; Costa,Marcel Madeira de; Casagrande,Everson;
Ciência & Saúde Coletiva , 2007, DOI: 10.1590/S1413-81232007000100020
Abstract: the existence of inactive dumps considerably increases the so-called "environmental liability"; so much so that the final destination of urban solid residues takes a prominent place on the list of environmental issues of societies1. in the state of santa catarina, it can be said that, currently, the real conditions of the "final destination deposits", or simply the inactive dumps, is officially unknown. this is maybe most evident in the carboniferous area of the state that already suffers from the environmental impact of coal mining. this study attempts to make a survey of the inactive dumps in the carboniferous area of santa catarina, analysing the risks they represent to public health and to the environment. the results gathered show that, of the eleven municipal districts in the carboniferous area, nine have inactive dumps. in these nine districts, there are eleven inactive dumps that, according to the this evaluation, represent a large risk to public health and the environment when the parameters analysed are taken into acount.
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