The suspension of copper droplets in the slag is considered. The copper/slug suspension is delivered as the product from the direct-toblister
process which is applied in the KGHM – Polska Miedź (Polish Copper) S.A. factory. The droplets / slag suspension was treated by
a special set of reagents (patented by the authors) to improve the coagulation process. On the other hand, the observations are made to
estimate if the melting / reduction process in the furnace is sufficiently effective to avoid a remaining of carbon in the copper droplets.
The coagulation process was carried out in the crucible (laboratory scale). However, conditions imposed to the coagulation / solidification
process in the laboratory scale were to some extent similar to those applied usually in the industry when the suspension is subjected to the
analogous treatment in the electric arc-furnace. Some suggestions are formulated how to improve the industrial direct-to-blister process.
The suspension of the copper droplets in the post-processing slag taken directly from the KGHM-Polska Miedź S.A. Factory (from the
direct-to-blister technology as performed in the flash furnace) was subjected to the special treatment with the use of the one of the typical
industrial reagent and with the complex reagent newly patented by the authors. This treatment was performed in the BOLMET S.A.
Company in the semi-industrial conditions. The result of the CaCO3, and Na2CO3 chemicals influence on the coagulation and subsequent
sedimentation of copper droplets on the crucible bottom were subjected to comparison with the sedimentation forced by the mentioned
complex reagent. The industrial chemicals promoted the agglomeration of copper droplets but the coagulation was arrested / blocked by
the formation of the lead envelope. Therefore, buoyancy force forced the motion of the partially coagulated copper droplets towards the
liquid slag surface rather than sedimentation on the crucible bottom. On the other hand, the complex reagent was able to influence the
mechanical equilibrium between copper droplets and some particles of the liquid slag as well as improve the slag viscosity. Finally, the
copper droplets coagulated successfully and generally, were subjected to a settlement on the crucible bottom as desired / requested.
The work presents investigation on the water droplet impingement at a substrate with three different surface coating. The experiments are carried out for two temperatures of the surface: 23ºC (room temperature) and -10ºC. The water droplet contact is recorded via ultra-fast camera and simultaneously via fast thermographic camera. The wetting properties are changing for subzero temperatures of substrates.
With widespread use of pesticides in modern agriculture, the impacts of spray drift have become a topic of considerable interest. The drifting of sprays is a highly complex process influenced by many factors. The paper presents results of experimental research on a drifting cloud of droplets dispersing from aircraft. Experiments were conducted to quantify spray drift from aerial applications of pesticide. Parallel to the blowing wind, the measurement line 800 m long was disposed. The relationships between the relative dose and the distance of drift as well as spray density and its structure on the measuring length have been established.
The study was conducted at the University of Nebraska Pesticide Application and Technology Laboratory in North Platte, Nebraska in July 2015. Two application volume rates (100 and 200 l · ha−1) and three nozzle types (XR, AIXR, TTI) were selected at two flow rates (0.8 and 1.6 l · min−1) and at a single application speed of 7.7 km · h−1. Each collector type [Mylar washed (MW), Mylar image analysis (MIA), water-sensitive paper (WSP), and Kromekote (KK)] was arranged in a randomized complete block design. Each nozzle treatment was replicated twice, providing six cards of each collector type for each nozzle treatment. A water + 0.4% v/v Rhodamine WT spray solution was applied, given the fluorescent and visible qualities of Rhodamine, which allows it to be applied over all the collector types. MW had the highest coverage at 18.3% across nozzle type, followed by WSP at 18%, KK at 12% and lastly by MIA at 4%. MW resulted in a 58% increase in coverage, WSP in a 56% increase, and KK only an increase of 39% when the volume rate was doubled from 100 l · ha−1 to 200 l · ha−1 across nozzle type. MW coverage was similar to KK for half of the nozzles (XR 11002, XR 11004, AIXR 11002). Droplet number density fixed effects were all significant for nozzle type and collector type (p < 0.001) as was the interaction of nozzle type and collector type (p < 0.001). Results from this study suggest a strong correlation to data produced with WSP and MW collectors, as there was full agreement between both types except for the TTI 11004. Using both collector types in the same study would allow for a visual understanding of the distribution of the spray, while also giving an idea of the concentration of that distribution.
Three methods of estimating radii of spray droplets are discussed and results of their practical application in the case of explosively produced water spray are reported. Parameters of model radii distributions are fitted using the least squares method. Finally, the data obtained for a number of tests are used for estimating fraction of explosion energy used for pulverization of water in the process of explosive production of water-spray.
This mini-review reports the recent advances in the hydrodynamic techniques for formation of bubbles of gas in liquid in microfluidic systems. Systems comprising ducts that have widths of the order of 100 micrometers produce suspensions of bubbles with narrow size distributions. Certain of these systems have the ability to tune the volume fraction of the gaseous phase – over the whole range from zero to one. The rate of flow of the liquids through the devices determines the mechanism of formation of the bubbles – from break-up controlled by the rate of flow of the liquid (at low capillary numbers, and in the presence of strong confinement by the walls of the microchannels), to dynamics dominated by inertial effects (at high Weber numbers). The region of transition between these two regimes exhibits nonlinear behaviours, with period doubling cascades and irregular bubbling as prominent examples. Microfluidic systems provide new and uniquely controlled methods for generation of bubbles, and offer potential applications in micro-flow chemical processing, synthesis of materials, and fluidic optics.
In agriculture, the mixing of pesticides in tanks is a common practice. However, it is necessary to previse possible physical-chemical implications of this practice, which may affect the efficiency of the treatments performed. Therefore, the objective of this study was to evaluate the effects of the addition of acaricide to insecticidal spray mixtures on the formation of spray droplets and the interaction with citrus leaves. The experimental design was totally randomized, in a (2 × 3 + 1) factorial scheme for seven treatments. Factor A corresponded to the spray mixture used (isolate or in the mixture). Factor B corresponded to the insecticides tested (lambda-cyhalothrin + thiamethoxam, phosmet, and imidacloprid) and the control consisted of a spray mixture with spirodiclofen only. Nine replications were performed for characterization of the spray droplet size spectrum and four replications for the analysis of the surface tension and the contact angle. The mixture of pesticides showed positive results in terms of application safety. The addition of acaricide to insecticide spray mixtures reduced the surface tension and contact angle of droplets on the adaxial surface of orange leaves. There was an increment in volume median diameter (VMD), a significant reduction in the volume of droplets with drift-sensitive size and improvement in the uniformity of droplet size. Therefore, the addition of acaricide to an insecticide spray mixture positively influenced spray droplet formation and the interaction with citrus leaves providing better coverage and droplet size fractions with an appropriate size for safe and efficient application.
It is challenging to obtain proper leaf wetting. An angled spray could overcome this impediment, but which spray angle is best suited to droplet size is still unknown. In an outdoor pot experiment, seven doses of cycloxydim and sethoxydim were sprayed with single-orifice standard, anti-drift, and air induction (having a fine, medium, and extremely coarse spray quality, respectively) flat fan nozzles, using spray angles of 10°, 20° backward, 0° (vertical), 10°, 20°, 30°, 40°, 50°, and 60° forward relative to the direction of nozzle trajectory on wild barley at the three-leaf stage. Generally, the forward angled spray was better than the backward angled spray. With a standard flat fan nozzle, the forward angling of spray from 0° to 20° reduced the ED50 from 60.24 to 39.85 g a.i. ⋅ ha−1 for cycloxydim and from 150.51 to 81.13 g a.i. ⋅ ha−1 for sethoxydim. With an anti-drift flat fan nozzle, the forward angling of spray from 0° to 30° reduced the ED50 from 72.57 to 50.20 g a.i. ⋅ ha−1 for cycloxydim and from 181.94 to 104.51 g a.i. ⋅ ha−1 for sethoxydim. With an air induction flat fan nozzle, the forward angling of spray from 0° to 40° reduced the ED50 from 102.96 to 45.52 g a.i. ⋅ ha−1 for cycloxydim and from 209.91 to 92.80 g a.i. ⋅ ha−1 for sethoxydim. More angling did not improve the efficacy of these herbicides. Our results revealed that larger spray droplets needed more spray angle than smaller spray droplets to achieve an equal control.
Coagulation and solidification of the copper droplets suspend in the liquid slag are usually accompanied by the appearance of the Cu-Cu2O eutectic. Locally, this eutectic is created in the stationary state. Therefore, frequently it has a directional morphology. Since the E = (Zn) + Zn16Ti – eutectic is similar in the asymmetry of the phase diagram to the Cu-Cu2O – eutectic, the (Zn) single crystal strengthened by the E = (Zn) + Zn16Ti precipitate is subjected to directional growth by the Bridgman’s system and current analysis. Experimentally, the strengthening layers (stripes) are generated periodically in the (Zn) – single crystal as a result of the cyclical course of precipitation which accompanies the directional solidification. These layers evince diversified eutectic morphologies like irregular rods, regular lamellae, and regular rods. The L – shape rods of the Zn16Ti – intermetallic compound appear within the first range of the growth rates when the irregular eutectic structure is formed. Next, the branched rods transform into regular rods and subsequently the regular rods into regular lamellae transitions can be recorded. The regular lamellae exist only within a certain range of growth rates. Finally, the regular rods re-appear at some elevated growth rates. The entropy production per unit time and unit volume is calculated for the regular eutectic growth. It will allow to formulate the entropy production per unit time for both eutectic structure: rod-like and lamellar one.