Horizontal Collector Research Articles

The Influence of Operator-Controlled Variables on Spray Drift from Field Crop Sprayers

Spray drift can be defined as the quantity of plant protection product that is carried out of the sprayed area by the action of air currents during the application process. This continues to be a major problem in applying agricultural pesticides. The purpose of this research is to measure the amount of sedimenting drift from a horizontal boom sprayer for different (drift reducing) spray application techniques under field conditions and to compare the results with the results from a reference spray, taking into account variations in meteorological conditions during the field drift experiments. Field drift measurements were performed for several combinations of nozzle type (standard flat-fan, low-drift, air inclusion) and size (ISO 02, 03, 04, and 06), spray pressure (2.0, 3.0, and 4.0 bar), driving speed (4, 6, 8, and 10 km h-1), and spray boom height (0.3, 0.5, and 0.75 m ) according to ISO 22866 by sampling in a defined downwind area at 24 different positions using horizontal drift collectors. The reference spray was defined as a standard horizontal spray boom without air support, a spray boom height of 0.50 m, a nozzle distance of 0.50 m, ISO 110 03 standard flat-fan nozzles at 3.0 bar (1.2 L min-1), and a driving speed of 8 km h-1, resulting in an application rate of approximately 180 L ha-1. Nozzle type as well as spray pressure, driving speed, and spray boom height, have an important effect on the amount of spray drift. Larger nozzle sizes, lower spray pressures and driving speeds, and lower spray boom heights generally reduce spray drift. Concerning nozzle types, air inclusion nozzles have the highest drift reduction potential, followed by the low-drift nozzles and the standard flat-fan nozzles. Drift results are closely linked with droplet size characteristics of the sprays.

Comparisons of Drift Reducing/Deposition Aid Tank Mixes for Fixed Wing Aerial Applications

Abstract A field study was conducted to determine the influence of adding spray drift control/deposition aid products to tank mix solutions for fixed wign aerial applications. Downwind horizontal drift, vertical drift, and droplet spectra characteristics in a canopy top were collected on water sensitive paper (WSP) for measurement and analysis. Spread factors for each spray mix sample were determined and were used as part of the analysis procedure with the canopy measurements. DropletScan™ was used to analyze the WSP. Percent area coverage for the horizontal and vertical drift profiles was used as a means to separate differences in treatments. DropletScan™ with adjusted spread factor coefficients was used to calculate Dv.1, Dv.5, and Dv.9 at the canopy top for each treatment. Differences in products at all horizontal and vertical collector positions were measured. When compared to water, results show that some of the products did not provide any benefits for drift reduction and, in fact, may have increased the drift potential. A few of the products exhibited the potential to reduce the amount of drift. Droplet sizes for Dv.1, Dv.5, and Dv.9 increased with the addition of the drift control/deposition aid products into the tank mix. The increases were variable across products and aircraft.

Solar chimney power plants for high latitudes

A solar chimney system for power production at high latitudes has been designed and its performance has been evaluated. A mathematical model and a code on MATLAB platform have been developed based on monthly average meteorological data and thermodynamic cycle. The thermal performance of a 5 MW nominal power production plant at three locations in Canada, namely Ottawa, Winnipeg and Edmonton, is studied. The sloped collector field is built at suitable mountain hills, which also functions as a chimney. Then a short vertical chimney is added to install the vertical axis air turbine. The results showed that solar chimney power plants at high latitudes may have satisfactory thermal performance and produce as much as 85% of the same plants in southern locations with horizontal collector field. The overall thermal performance of these plants is a little less than 0.5%.

Direct steam generation in parabolic troughs: Final results and conclusions of the DISS project

This paper presents a summary of the main results and conclusions achieved in the DISS (Direct Solar Steam) project. The test facility implemented at the Plataforma Solar de Almería (PSA) in 1997–8, the so-called PSA DISS test facility, was operated for more than 3000 h in 1999–2000 and 2001 to investigate the Direct Steam Generation (DSG) process under real solar conditions. The feasibility of the DSG process in horizontal parabolic trough collectors has been proven and an important know how has been acquired by the project partners regarding the thermo-hydraulic parameters of the water/steam flow in DSG solar fields.

Testing a New Anti-Zebra Mussel Coating with a Multi-plate Sampler: Confounding Factors and other Fuzzy Features

In situ experiments were conducted to assess the use of multi-plate samplers for antifouling experiments and to test the antifouling effectiveness of a chitin-based coating against zebra mussels (Dreissena polymorpha). A series of multi-plate samplers consisting of three parallel plates coated with chitin, and untreated control samplers, were submerged horizontally or vertically in a marina of the St Lawrence River for 3 1/2 months (July-October) in 1998 and 1999. Mussels attached to the chitin-treated substrates were on average 2.75 times more abundant than on the control samplers, indicating that chitin is not effective as an antifouling agent against zebra mussels. The abundance, size distribution and spatial dispersion of mussels on the plates varied both between plates and between top vs bottom sides of plates in horizontal collectors, but not in vertical samplers. The three plates composing each multi-plate horizontal sampler do not represent true replicates for statistical analysis. The bottom side of plates exhibited the least variability and might therefore serve as the experimental unit. Substrate heterogeneity and plate orientation were identified as confounding factors to be controlled for in future experiments. Sunlight exposure and colonization by sponges strongly influenced zebra mussel abundance and should be considered when performing in situ experiments. Because of the influence of uncontrolled factors, it is recommended that in situ pilot studies be conducted to statistically test the effectiveness of antifouling products once the threshold level of the desired effectiveness is defined.

SIMULATION OF A THERMAL SOLAR POWER PLANT OPERATING ON MARS UNDER CLEAR SKY AND DUST STORM CONDITIONS

The power plant analyzed in this work consists of a selective solar collector–thermal engine combination. The paper focuses on solar power plant operation under various weather conditions during all seasons on Mars. Meteorological data measured at Viking Landers (VL) sites were used in computations. Two strategies to collect solar radiation were analyzed: a solar horizontal (H) collector and a solar collector whose tilt and orientation are continuously adjusted to keep the receiving surface perpendicular to Sun rays (P). Both a low and a high efficiency thermal engine were considered. All the computations were performed for a selective solar flat-plate collector similar in size to the Mars Pathfinder's Sojourner. Results show that generally the influence of latitude on performance is important. In some situations, the meteorological effects compensate the latitudinal effects and the output power is quite similar at both VL1 and VL2 sites. In case a low-efficiency engine is coupled to a horizontal collector, the solar efficiency does not exceed 0.13 at VL2 site. It is lower during summer and higher during winter dust storms. In case the low-efficiency engine is coupled to a P collector, the solar efficiency increases during summer. The solar efficiency is as high as 0.18 in case of a horizontal collector attached to a high-efficiency engine. If the high-efficiency thermal engine is connected to a P collector the solar efficiency increases significantly during summer and spring but does not exceed 0.18. The power provided by a system consisting of a horizontal collector and a low-efficiency engine does not exceed 7 W . Using a high engine coupled to a horizontal collector leads to a power output up to 13 W during spring, autumn and winter. The P collector is recommended mainly during summer and spring in combination with high-efficiency engines. In this case the solar efficiency could be as high as 25 W . The performance of PV cell power systems and properly designed dynamic solar power plants operating on Mars is comparable.

Design and optimisation of a combination solar collector–thermal engine operating on Mars

A “dynamic” solar power plant (which consists of a solar collector–thermal engine combination) is proposed as an alternative for the more usual photovoltaic cells. A model for heat losses in a selective flat-plate solar collector operating on Mars is developed. An endoreversible Carnot cycle is used to describe heat engine operation. This provides upper limits for real performances. The output power is maximized. Meteorological and actinometric data provided by Viking Landers are used as inputs. Two strategies of collecting solar energy were considered: (i) horizontal collector; (ii) collector tilt and orientation are continuously adjusted to keep the receiving surface perpendicular on the Sun’s rays. The influences of climate and of various design parameters on solar collector heat losses, on engine output power and on the optimum sun-to-user efficiency are discussed.

98/03936 A low cost solar water heater suitable for rural, as well as urban, areas of Vietnam

The built-in-storage type of solar water heater will be suitable for rural as well as urban areas of Vietnam, in general, and the Hanoi region, in particular (mainly for domestic purposes). In this paper, a thermal model for optimisation of the design parameters and estimation of the effect of various parameters on the thermal performance of this solar water heater is presented. The paper also presents the numerical computations with the climatic conditions of the Hanoi region for three cases: (i) using a horizontal collector; (ii) using a sloped collector without reflector: and (iii) using a sloped collector with reflectors. On the basis of the numerical computations, conclusions for the application of this solar water heater in Vietnam have been made.

Fluxes of methane between landfills and the atmosphere: natural and engineered controls

Abstract. Field measurement of landfill methane (CH4) emissions indicates natural variability spanning more than seven orders of magnitude, from less than 0.0004 to more than 4000 g/m2 per day. This wide range reflects net emissions resulting from production (methanogenesis), consumption (methanotrophic oxidation), and gaseous transport processes. The determination of an ‘average’ emission rate for a given field site requires sampling designs and statistical techniques which consider spatial and temporal variability. Moreover, particularly at sites with pumped gas recovery systems, it is possible for methanotrophic microorganisms in aerated cover soils to oxidize all of the CH4 from landfill sources below and, additionally, to oxidize CH4 diffusing into cover soils from atmospheric sources above. In such cases, a reversed soil gas concentration gradient is observed in shallow cover soils, indicating bidirectional diffusional transport to the depth of optimum CH4 oxidation. Rates of landfill CH4 oxidation from field and laboratory incubation studies range up to 166 g/m2 per day, among the highest for any natural setting, providing an effective natural control on net emissions. It has been shown that methanotrophs in landfill soils can adapt rapidly to elevated CH4 concentrations with increased rates of CH4 oxidation related to depth of oxygen penetration, soil moisture, and the nutrient status of the soil.Estimates of worldwide landfill CH4 emissions to the atmosphere have ranged from 9 to 70 Tg/y, differing mainly in assumed CH4 yields from estimated quantities of landfilled refuse. At highly controlled landfill sites in developed countries, landfill CH4 is often collected via vertical wells or horizontal collectors. Recovery of landfill CH4 through engineered systems can provide both environmental and energy benefits by mitigating subsurface migration, reducing surface emissions, and providing an alternative energy resource for industrial boiler use, on‐site electrical generation, or upgrading to a substitute natural gas. Manipulation of landfill cover soils to maximize their oxidation potential could provide a complementary strategy for controlling CH4 emissions, particularly at older sites where the CH4 concentration in landfill gas is too low for energy recovery or flaring. For the future, it is necessary to better quantify net emissions relative to rates of CH4 production, oxidation, and transport. Field measurements, manipulative studies, and model development are currently underway at various spatial scales in several countries

Experimental verification of aeolian saltation and lee side deposition models

ABSTRACTWe report results of experiments intended to test the validity of a model for aeolian saltation and the resulting pattern of deposition on the lee side of aeolian dunes. In steady sea‐breeze conditions on a 3‐m‐tall dune at Point Año Nuevo, California, we measured simultaneously the near‐brink wind speed and the deposition on both horizontal and lee face collector platforms. We then used the details of the deposition patterns to constrain approximate values of parameters in a numerical model of the deposition rate that incorporates the essence of the saltation process. Best fits to the data constrain a parameter that controls the probability distribution of liftoff speeds. In addition, the total vertical number flux of grains is constrained to roughly 107−108 grains m−2 s−1 at shear velocities of 0.33–0.40 m s−1. The lee side deposition pattern, which shows the expected maximum in deposition rate at a distance of several decimetres from the brink, is also well fit by the model. In addition, simultaneous collection of horizontal and lee deposition patterns, along with the numerical simulation of these patterns, strongly implies that the windfield in the lee of this particular dune is best described as a non‐recirculating wake. Grainflows on the lee face are caused by failure of grainfall depositional bumps. Our results suggest that the principal effect of increased wind speed is to increase the frequency of grainflows. rather than to increase their size, implying that very large, thick grainflows require a different mechanism.

Significance of copepod emergence to benthic, pelagic, and phytal linkages in a subtidal seagrass bed

The role of meiobenthic copepod emergence in linkages among benthic, pelagic, and phytal habitats was examined in a subtidal seagrass (Tl~alassia testudjnurn) bed at the mouth of Tampa Bay, Florida. USA. On 4 dates the ability of emerging copepods to affect the density and composition of benthic and phytal assemblages was tested during 2 h periods of minimum and maximum emergence. Copepod exchanges between benthic and phytal habitats and the duration of pelagic excursions also were examined throughout a night by measuring settlement into 2 types of sediment traps and onto natural and defaunated seagrass blades. The ability of emerging fauna to disperse through the water column was determined from horizontal collectors. Changes In copepod densities and composition during periods of active emergence did not indicate an unequivocal exchange between sediment and seagrass blade assemblages. Copepod resettlement onto the sediments was greater during periods of increased emergence and suggested that emerging copepods typically did not remain in the water column for a prolonged (> 2 h) time. The dispersal of copepods through the water column was haphazard and unaffected by prevailing currents. Species and habitat affiliation influenced both the dispersal and settlement behaviors of emerging copepods. Although appreciable numbers of sediment-associated copepods can enter and disperse through the water column, our results suggest that the effects of emergence on linkages between benthic, pelagic, and phytal habitats are minimal or limited in duration.

Estimating direct, diffuse, and global solar radiation for various cities in Iran by two methods and their comparison with the measured data

Two computational methods for calculating hourly, daily, and monthly average values of direct, diffuse, and global solar radiation on horizontal collectors have been presented in this article for location with different latitude, altitude, and atmospheric conditions in Iran. These methods were developed using two different independent sets of measured data from the Iranian Meteorological Organization (IMO) for two cities in Iran (Tehran and Isfahan) during 14 years of measurement for Tehran and 4 years of measurement for Isfahan. Comparison of calculated monthly average global solar radiation, using the two models for Tehran and Isfahan with measured data from the IMO, has indicated a good agreement between them. Then these developed methods were extended to another location (city of Bandar-Abbas), where measured data are not available. But the work of Daneshyar [1] predicts its monthly global radiation. The maximum discrepancy of 7% between the developed models and the work of Daneshyar [1] was observed.

LETTERS

A representative of the makers of Ranney wells, a type of horizontal radial collector well, clarifies the US Environmental Protection Agency's position on Ranney wells in relation to groundwater under the influence of surface water as defined regulated by the Surface Water Treatment Rule.

Performance of a simple flat plate solar collector at an equatorial location

Abstract The performance of a solar flat-plate collector installed at an equatorial location, Port Harcourt (latitude 4°51′N, longitude 7°01′E), Nigeria, has been investigate. It is found that the variation of fluid stagnation temperature wit local time is similar for a tracking collector as for a horizontal one whose longer axis is oriented in a north-south direction. It is observed that a tracking collector gives a higher ratio of fluid stagnation temperature to ambient temperature than either a horizontal or tilted collector. In the case of a tilted collector, it is found that the stagnation fluid temperature for an east-facing collector reaches a peak value earlier for larger angles of tilt (with respect to the horizontal) while for a west-facing collector, peak temperature is reached later for larger angles of tilt. Finally, the working efficiency of the collector is found to be highest (about 62%) when the collector is placed horizontally with its longer axis oriented in the east-west direction as against a north-south orientation or when the collector tracks the sun's daily east-west movement.

DESIGN FOR LUMBER DRY KILN USING SOLAR/WOOD ENERGY IN TROPICAL LATITUDES

ABSTRACT Developing countries with a timber resource that can be manufactured into finished products either for local use or export often lack the capital to build high-cost dry kilns. Many of these countries are in the tropics where solar radiation and ambient temperatures are high. The low-cost solar/wood energy lumber dry kiln described in this report was designed and tested for such countries where solar dry kilns can be built and operated at low cost. The design is for a 14-m6,000-fbm capacity kiln having an insulated drying compartment, an external horizontal solar collector, and a furnace room containing a wood burner. Capacities larger or smaller than 6,000 fbm are also possible. This design allows collector and wood burner sizing to match the energy demands of the dryer. The design also incorporates low-cost controls that allow unattended drying when operated as a solar-only dryer. Manual firing is necessary when the wood-burning system is supplying the energy.

Criteria for Determining Buoyancy Effects on Turbulent Forced Convection in an Asymmetrically Heated Horizontal Channel

ABSTRACT EFFECTS of buoyancy on fully developed turbulent forced convection in an asymmetrically heated horizontal channel were investigated. This study provides criteria to determine the onset and ceasing of buoyancy effects in turbulent forced heat transfer within a horizontal air flat plate solar collector. Nusselt numbers were calculated for both the lower and upper surfaces in the fully developed region. The modified buoyancy parameter Gri*/Re^2 ^^s varied from 0.04 to 10.87 for the lower surface (i=l) and from 0.01 to 5.42 for the upper surface (i=2). For the lower surface with Grj*/Re^2 {Q^^ than 1.6 or greater than 5.8, the Nusselt number could be calculated to within 10% using empirical equations for either turbulent forced or natural convection, respectively. For 1.7 < GY^'^/RQ^^ < 5.8, turbulent mixed convection occurred. For the upper surface with Gr2*/Rej^2 j^^s than 0.17, the Nusselt number could be predicted to within 10% by a turbulent forced convection equation.

横須賀市走水の地下水湧出機構

The Hashirimizu spring had been utilized for the city water supply of Yokosuka City, since one hundred years ago.“ Where the spring water come from ?” was a mysterious question for a long time.From 1976 to 1978, we could chtllenge to elucidate the semieternal puzzle by means of thermal-infrared imagery method (on air), measurement of temperature of sea-water (by sea), gammaray survey (carborn), geological test boring, pumping water well test and others.It was presumed that the origin of the spring water would be came up from plural brecciated rock zones in Neogene formation.The brecciated zones are extending from the western coast to the eastern coast of Miura peninsula and accordingly the spring has distinct characteristics in constant flowing quantity and water quality all the year round, in spite of its too-small catchment-area compared with yielding amounts from the spring.Next, we could understand that, the yield of the spring had only 300 cubic meters a day or a little more as a surplus, beyond the daily yield of 2,700 cubic meters a day. This matters was actually certified by installation of a horizontal water collector with radially installed strainers at a suitable site to get superfluous ground-water.

Deposition of particles on a cylindrical collector

We have studied the deposition of latex particles of diameter 0.8, 2.8, 5.7, 9.5, and 25.7 μm on a cylindrical collector of diameter 250 μm. Experiments were performed with a horizontal and a vertical cylinder. The position of the particles deposited on the horizontal collector shows the contributions of the various transport mechanisms in a qualitative way. From the deposition rate on the vertical collector the collector efficiency is calculated. The results are compared with existing theories. The data deviate considerably from predictions of the classical interception theory, but agree well with the theory of particle capture including London-van der Waals and viscous forces.

Kinetically caused saturation in the deposition of particles or cells

Particle deposition from a stagnant suspension onto a flat horizontal collector is theoretically analyzed, using two different approximations, emphasizing the effect of already deposited particles on subsequent deposition. Situations are identified in which the deposition is highly self-retarding, reaching an apparent saturation. This saturation has a kinetic origin and offers a qualitative explanation of experimental evidence on the deposition of colloidal particles, tumor cells, and platelets. It also leads to a physicochemical mechanism of the events responsible for the primary arrest of bleeding, following an injury.

Sioux Falls Restores Four Wells With Collector Pipe

This article was presented as a paper at the 41st Annual Meeting of the South Dakota Water and Wastewater Association, September 1975. The Sioux Falls Water Department was faced with a problem: how to rejuvenate four Raney horizontal collector wells constructed in 1957 that had declined in production to as little as 60 percent of their original capacity of 1400gpm. An informal proposal from a well‐cleaning contractor revealed that it would cost approximately $17,000 to mechanically clean one 50‐ft deep well with 480 ft of 8‐in. slotted horizontal collector pipe. Needless to say the price was hardly attractive especially since the water department owned six such wells. (Two more were under construction.) This article discusses the alternative restoration method that they chose, including the outcome of the project.