Simple agrocontroller

Jednoduchý agropočítač je realizace řídícího počítače postřikového stroje v zemědělské technice. Úvod popisuje typy jednotlivých postřikovačů a jejich hlavní rozdíly. Hydraulické schéma zobrazuje rozložení regulátorů, ventilů, hadic apod. Kapitola Požadavky definuje potřebné funkce a proměnné. Další kapitola vysvětluje strukturu rozložení jednotlivých částí agropočítače. Následně definuje požadované funkce a vlastnosti těchto částí pomocí reálných obvodů a součástek a metody získávání potřebných hodnot. Praktická ukazuje, jak vypadají desky plošných spojů a jsou popsány funkce a vlastnosti agropočítače.Simple agrocontroller is a realization of control computer of spray machine in agriculture technique. Introduction describes the types of individual sprayers and their main differences. Hydraulic scheme displays the layout of regulators, ventils, hosepipes etc. Chapter Requirements defines needed functions and variables. Next chapter explains the structure of the layout of agrocontroller´s individual parts. Also defines required functions and features of these parts with real circuits and components and methods of gaining required values. Practical part show how printed circuits boards look like and what are features and properities of agrocontroller.

A Physical Calibrator for Partial Discharge Meters

This article offers an alternative method of calibrating partial discharge meters for research and teaching purposes. Most current modern calibrators are implemented as precise voltage pulse sources with a coupling capacitor. However, our calibrator is based on the physical principles of dielectric materials distributed in a plane or space. Calibrator design is unique and there is an attempt to get closer to the behavior of the measured real objects. The calibration impulses are created by energy from a high voltage power supply at the specific or nominal value of the applied voltage. At the same time, it is possible to simulate the value and quantity of the discharges and their position in the object relative to the input electrodes. The calibrator creates conditions as a real measured object with adjustable parameters. This paper describes a design of this type of calibrator, its implementation, numerical simulation of discharge values and laboratory measurements with functional verification using the Tettex 9520 calibrator and galvanic measured system DDX 7000/8003 and DDX 9121b. All measurements are carried out using the CVVOZEPowerLab Research Infrastructure equipment

Experimental investigation of suitable cutting conditions of dry drilling into high-strength structural steel

Dry machining is one of the main ways to reduce the environmental burden of the machining process and reduce the negative effect of the cutting fluid and aerosols on operators. In addition, dry machining can reduce overall machining costs and, in the case of large workpieces, reduce the extra work associated with removing residual cutting fluid from the workpiece and adjacent area. For high-strength structural steel products, it is typical to drill holes with larger diameters of around 20 mm. Therefore, this work is devoted to the investigation of the dry drilling process carried out on a workpiece made of S960QL steel with a helical drill with a diameter of 21 mm. The aim was to find suitable cutting conditions for dry drilling with regard to process stability and workpiece quality. An experiment performed with a coolant served as a comparison base. A dry drilling experiment was performed with cutting speeds from 30 to 70 m center dot min(-1) and feeds from 0.1 to 0.3 mm center dot rev(-1), and with the results of this experiment, the same experiment with flood cooling was performed. During the drilling process, spindle torque values were recorded using the indirect spindle current recording method. The macroscopic chip morphology was studied to understand the cutting process. The chip thickness ratio was measured, as well as the maximum diameter of spiral chips. On the final workpiece, the qualitative and dimensional parameters of the holes were evaluated, such as the diameter, cylindricity and surface roughness, depending on the change in the cutting conditions and cutting environment. Evaluation of the obtained data led to the following conclusions. When drilling the S960QL material, there is only a very small increase in the drilling torque during dry drilling compared to drilling with cutting fluid. The increase in friction demonstrated by the chip thickness coefficient is significant. The influence of the environment on the dimensional accuracy showed a tendency for a slight increase in the holes' diameters during dry machining. In comparison, the cylindricity of the dry-drilled holes shows a lower deviation than the holes drilled with cutting fluid. The surface roughness of the holes after dry drilling is affected by the increased friction of the outgoing chips, despite the resulting parameters being very good due to the drilling technology standards. This work provides a comprehensive view of the dry drilling process under defined conditions, and the results represent suitable cutting conditions to achieve a stable cutting process and a suitable quality of drilled holes.Web of Science1416art. no. 438

Novel drill geometries for dry drilling of stainless steel

One completely new geometry and two modified chip breaker geometries were designed to increase the stability and reliability of the stainless steel dry drilling process. Experiments were performed and the results of individual tools were compared with a conventional solid carbide twist drill Gühring Ratio with a diameter of 5 mm. A matrix of three feed rates (0,03–0,07 mm/rev) and three cutting speeds (20–30 m/min) was designed for the cutting conditions. Precipitation-hardenable stainless steel 17-4 PH was chosen as a workpiece. During the experiment, the values of thrust force, spindle torque, temperature of the tool, surface roughness, chips morphology and chips division were recorded and compared with the reference tool. The results showed that compared to the reference tool A, the tool C - a multipoint drill with grooves through the cutting edge achieve approximately 4 % lower values of thrust force and 10–15 % lower values of spindle torque. Tool D with a step drill geometry achieve approximately 17 % lower values of thrust force and 10–15 % lower values of spindle torque and there is no chip clogging in the flute with C and D geometries. This effect is confirmed by the fact the spindle torque basically does not increase with the increasing depth of drilling. Tool B – new designed geometry achieve approximately 15 % lower values of thrust force and similar spindle torque values as the reference drill A. Tool temperature is a very important factor when dry drilling. Compared to the reference drill A, it was possible to achieve the tool temperature reduction of 20 % with the new geometry B, as well as with the multipoint drill C reduction by 26 % and with the step drill D reduction approximately by 30 %. All the modified drills also achieved a reduction in the surface roughness of the drilled holes. By 17 %, 35 % and 48 % lower surface roughness Ra was achieved with drills B, C and D. Chip morphology was significantly different for the tested drills. Conventional twist drills A and B generated helical short chips. While C and D twist drills with divided cutting edges generated ribbon snarled chips. Thanks to the reduction of cutting forces and temperature, it is possible to stably operate the drilling process with a higher cutting speed and feed rate, which leads to an increase in the efficiency and reliability of the machining process.Web of Science9252050

Comparison of vision function and coordination of upper limbs of Erasm students in the Belgium and Czech republic

Bakalářská práce se zabývá srovnávací analýzou zrakové stereopse a koordinací horních končetin u studentů v Belgii a České republice. Pro účely zjištění zrakové stereopse (prostorového vidění) byl použit test "Titmus Fly Stereotest" a pro zjištění kvality koordinace horních končetin test "Vyhazování a chytání míčku v leže" (Měkota, Blahuš, 1983). Testování se zúčastnilo 68 studentů Erasmu z Belgie a 59 studentů vysoké školy z České republiky. Na základě vyhodnocení získaných dat jsme dospěli k následujícím závěrům. Získaná data byla vyhodnocena s cílem posoudit kvalitu stereopse a koordinaci horních končetin.ObhájenoThe bachelor thesis deals with comparative analysis of visual stereoscopy and coordination of upper limbs in students in Belgium and the Czech Republic. The "Titmus Fly Stereotest" test was used to determine the visual stereotype and to test the quality of upper limb coordination in the "Ejecting and Catching the Lying Ball" test (Měkota, Blahuš, 1983). In this research is 68 Erasmus students from Belgium and 59 university students from the Czech Republic. The obtained data were evaluated to assess the quality of stereopsis and the coordination of the upper limb

Textile waveguide

Diplomová práce se zaměřuje na výrobu vlnovodového filtru. Práce je rozdělena do 8 kapitol. V práci je shrnuta teorie možných provedené vlnovodového filtru, použité materiály, jejich vliv a rizika při výrobě. Následně jsou, pospány možné postupy realizace a vztahy nezbytné k návrhu filtru, jejich simulace i provedení v praxi. Na závěr jsou shrnuty, porovnány a popsány dosažené výsledky.Diploma thesis is focused on manufacturing process of waveguide filter. Thesis is divided to 8 chapters. There is summarized theory of possible execution of waveguide filter, used materials, their influence and risks during production. Then are described possible steps of realization and necessary relations for its design, simulation and also practical realization. At conclusion are summarized, compared and described reached results.

Proposal for Financing a Development Project

The bachelor thesis deals with the financing of development projects. The main goal is financing proposals using external and internal sources, their risks and areas of development. The content of the work is also the presentation of a specific development project and subsequent analysis of financing. The bachelor's thesis takes into account current events in the real estate market and two variants of development are proposed. The first variant is based on the prices of demand and supply on the current market, the second variant predicts a decrease in housing unit prices by 10 %

Transfer of delictual liability in competition law

Transfer of delictual liability in competition law The issue of delictual liability for anti-competitive practices and subsequent identification of party which is to be penalized for them is, with regard to effective protection of competition, a crucial one. However, it is also a topic which is, with a few notable exceptions, often addressed only superficially. This work therefore aims to perform thorough analysis of rules applicable to transfer of delictual liability both on European and Czech national level. For this purpose, it is divided into two major and comparatively separate parts. First of them is devoted to a detailed analysis of the European court of justice case-law related to the possibility of transfer of liability from the original infringer to a different legal entity. The aim is not only to identify particular criteria, which may affect such transfer of liability, but also to illustrate the direction in which the case-law of the European court of justice evolved and in which it is probable to continue heading in the future. The second part of this work deals with regulation of the transfer of liability within the Czech legal framework, commencing with adoption of Act no. 63/1991 Coll., on the Protection of Competition, up to the present. Considering the decisive influence of the..

A note on imperfect hedging: a method for testing stability of the hedge ratio

Companies producing, processing and consuming commodities in the production process often hedge their commodity expositions using derivative strategies based on different, highly correlated underlying commodities. Once the open position in a commodity is hedged using a derivative position with another underlying commodity, the appropriate hedge ratio must be determined in order the hedge relationship be as effective as possible. However, it is questionable whether the hedge ratio determined at the inception of the risk management strategy remains stable over the whole period for which the hedging strategy exists. Usually it is assumed that in the short run, the relationship (say, correlation) between the two commodities remains stable, while in the long run it may vary. We propose a method, based on statistical theory of stability, for on-line detection whether market movements of prices of the commodities involved in the hedge relationship indicate that the hedge ratio may have been subject to a recent change. The change in the hedge ratio decreases the effectiveness of the original hedge relationship and creates a new open position. The method proposed should inform the risk manager that it could be reasonable to adjust the derivative strategy in a way reflecting the market conditions after the change in the hedge ratio