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The aim of this study was to determine the influence of boom height above a crop stand and the spacing between nozzles and diffusers in an over-row sprayer on the uniformity of the horizontal spray distribution and the uniformity of the air velocity distribution. The experimental setup involved a prototype over-row sprayer equipped with a boom with a working width of 8 m and ten air diffusers with spray nozzles. Air diffusers were connected to one or two nozzles each, and they were installed on the boom at intervals of 60, 80, and 90 cm. Terminal airflow velocity at a canopy is determined by the height of a sprayer boom and the diffuser spacing, ranging from around 2 m s–1 to around 27 m s–1. The sprayer boom should be positioned at a height of 50 cm above a crop stand due to the difference between the minimum and maximum airflow velocities. The horizontal spray distribution was more uniform when the sprayer was equipped with hollow-cone nozzles instead of flat-fan nozzles; hollow-cone nozzles should be applied if the distance between nozzles needs to be adjusted to the row width and row spacing. The analyzed coefficients did not exceed 10% when the boom was positioned 50 cm above the crop stand and when the nozzles were spaced 80 cm apart, which suggests that, in this configuration, sprayers equipped with hollow-cone nozzles can also be applied to close-grown crops. [ABSTRACT FROM AUTHOR]

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Mint is one of the most valuable herbs, and has multiple benefits and uses. The effect of cultivation methods on the biometric parameters of mint plants was determined by comparing a hydroponic system involving moveable flood tables with plastic covers and a raised-bed growing system in an open field. The morphometric parameters of mint plants may vary depending on species and cultivation method. An interaction between both factors was observed for plant height, leaf length, leaf width, and the number of leaves. Spearmint and apple mint grown under field conditions were characterized by higher average values of plant height and width and a higher number of branches than hydroponically grown plants. In the hydroponic system, the number of branched stems decreased by up to 80% with increased plant height. Leaf width was correlated with the total number of leaves. An increase in the number of leaves per plant induced a decrease in leaf width (up to 61%). Field-grown mint is usually characterized by higher marketable and total yields than hydroponically grown mint. However, the marketable yield of apple mint was approximately 50% higher in the hydroponic system than in the field. [ABSTRACT FROM AUTHOR]

The aim of this study was to measure the physical attributes of seeds of selected lilac species and to describe the correlations between these properties and seed mass for seed processing and treatment. Basic physical parameters were measured in the seeds of five lilac species and the results were used to calculate aspect ratios describing seed shape and size. The average values of the measured properties ranged from 3.57 to 5.98 m s−1 for terminal velocity, from 6.20 to 9.61 mm for seed length, from 2.19 to 3.94 mm for seed width, from 0.85 to 1.21 mm for seed thickness, from 5.9 to 19.2 mg for seed mass, and from 32° to 44° for the angle of external friction. Seed mass was bound by the strongest correlations with terminal velocity (Amur lilac, Hungarian lilac, and Pekin lilac), thickness (broadleaf lilac), and width (Japanese tree lilac). Seed thickness followed by terminal velocity were the primary distinguishing features of lilac seeds. Therefore, lilac seeds should be sorted with the use of sieve separators with longitudinal openings or pneumatic separators. These devices effectively sort lilac seeds into fractions with uniform seed mass, which can facilitate the propagation of lilacs in nurseries and the production of high-quality seedlings, thus promoting the sustainable use of natural resources and production materials. In medium-sized and large seed fractions, the coefficient of variation of seed mass can be decreased by up to 50% relative to unsorted seeds. [ABSTRACT FROM AUTHOR]

An analysis of the risk of failure in the safety valve – tank with propane-butane (LPG) system has been conducted. An uncontrolled outflow of liquid LPG, caused by a failure of the above mentioned system has been considered as a threat. The main research goal of the study is the hazardous analysis of propane-butane gas outflow for the safety valve – LPG tank system. The additional goal is the development of an useful method to fast identify the hazard of a mismatched safety valve. The results of the research analysis have confirmed that safety valves are basic protection of the installation (tank) against failures that can lead to loss of life, material damage and further undesired costs of their unreliability. That is why a new, professional computer program has been created that allows for the selection of safety valves or for the verification of a safety valve selection in installations where any technical or technological changes have been made.

Florets are the main edible parts of cauliflowers and broccoli, but stalks and leaves are also used in the production of vegetable soup mixes. In industrial processing lines, large cauliflower and broccoli inflorescences have to be separated into smaller florets with a diameter of 2 to 6 cm. Simple and inexpensive machines for floretting cauliflowers and broccoli, including devices that can be used in small-scale production, are in short supply on the market. Therefore, the aim of this study was to design a floretting machine composed of a load-bearing frame, a processing table, a crushing chamber and a horizontal conveyor. In the first stage of the process, one of the two conical knives is used to separate florets and leaves from stalks. The stalks fall into a container under the processing table, and the leaves are picked manually from the material on the table and are placed in a separate container. In the second stage, the separated florets are manually fed into the crushing chamber where larger florets are separated into smaller parts. The crushing.chamber is composed of a rotating crushing roller and a fixed screen at the bottom. Florets that have been cut into the appropriate size pass through the screen and fall onto a conveyor belt under the crushing chamber. The quality of the floretting process can be inspected visually by the operator, and impurities or excessively damaged florets can be removed from the conveyor belt. In the final stage, the separated florets are transported to a container. The designed machine can be operated directly on the farm; therefore, the resulting produce is fresher than products that are transported and separated in a food processing plant. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of this study was to evaluate the effects of the friction plate hardness and surface orientation of a friction plate on the angle and coefficient of static friction of cereal kernels. The angle of static friction of kernels representing four major cereal species was measured on six friction plates with different hardness. The friction plates were placed in position where their surface orientation was perpendicular or parallel relative to their inclination tilt. The experimental material comprised the so-called flat seed units, where each unit consisted of three spaced kernels. The angle of static friction of every flat seed unit was measured with a dedicated device in three replications, and average values of that angle were calculated. The kernels' angle of static friction varied considerably from 13° to 33° within the analyzed range of changes in the surface characteristics of friction plates. The average angle of static friction was influenced mainly by the surface orientation of the friction plate that came into contact with cereal kernels. The angle of static friction was 17.5% to 56.5% higher when the friction plate had perpendicular rather than parallel surface orientation. The frictional properties of kernels were less influenced by plate hardness, and clear relationships were not observed in this respect. The kernels' coefficient of static friction remained fairly constant within the analyzed range of plate hardness values, and it was estimated at 0.4 on plates with a perpendicular surface orientation and at 0.3 on plates with a parallel surface orientation. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the correlations between the external friction angle of wheat kernels vs. the roughness of the friction plate and the basic physical properties of kernels. The average external friction angle ranged from 17° to 24°, and its value increased with an increase in surface roughness. The analyzed relationship was well described by a logarithmic function. The dimensions, mass, geometric mean diameter, aspect ratio, sphericity index and density of wheat kernels had practically no influence on the angle of external friction, which indicates that wheat kernels cannot be reliably sorted based on their frictional properties. [ABSTRACT FROM AUTHOR]