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New series of ball screws
Chalupa, Josef ; Ostrý, Lubomír (referee) ; Marek, Jiří (advisor)
This thesis deals with construction of rotary-nut ball screw. In the first chapter technical research at the current state of linear positioning systems and matters associated with them is listed. The next chapter treats of basic concepts and designs referring to ball screws. Further on the boundary between rotary ball screw and rotary- nut ball screw is described. On basis of restrictions and selected criterions solution of one size of rotary – nut ball screw with all the calculations.
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The effect of castration method of pigs on growth, carcass value and pork quality
Chalupa, Josef ; Okrouhlá, Monika (advisor) ; Urbanová, Daniela (referee)
This thesis describes the issue related to the influence of pigs castration methods on their growth, slaughter value and meat quality. Nowadays, it is legal the surgical castration within anaesthesia in young boards, younger than 7 days. This method is the most used by pig breeders for several reasons, but especially it is neither financially or time demanding. Even though this surgical invention should be performed by veterinarian, but due to it simplicity it is performed by educated farm workers in practice.
The problem will occur in 2018. In this year the surgical castration without anaesthesia will be prohibited because of animal pain and the effort to improve animal welfare.
The main reason of piglet castration is the boar taint, which is connected to sexual maturation and hormone activity. The main substances, which caused the boar taint, are androstenone, skatole and indole. Androstenone is a steroid hormone produced in the testis with the typical urine like odor. Skatole is the substance with fecal odor and it is produced in the hind gut. Another reason for piglet castration is higher activity, even aggression in
non-castrated pigs. The aggression is a negative effect causes injuries between animals. The next negative effect is the aggression against breeders.
Based on these facts, there are numerous studies focused on possible solutions of this problem. There are describes surgical castration with local or total analgesia. The most practical, seems to be the local analgesia. Another method is the immune castration, where it is based on the hormone castration. There are applied 2 injections with the time lag. The first is applied in 13 to 16 weeks old pigs, the second in 21 to 22 weeks old pigs.
The alternative method for relieving the pain is the boar fattening, where is important to decreased the aggression and level of boar taint by different methods. One of the methods is fattening pigs to lower slaughter weight (between 80 to 90 kg), or the breed choice. An interesting method is also sperm sexing, where is an effort for the highest female production. However, this method is not relevant for everyday practice, due to its difficulty.
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New series of ball screws
Chalupa, Josef ; Ostrý, Lubomír (referee) ; Marek, Jiří (advisor)
This thesis deals with construction of rotary-nut ball screw. In the first chapter technical research at the current state of linear positioning systems and matters associated with them is listed. The next chapter treats of basic concepts and designs referring to ball screws. Further on the boundary between rotary ball screw and rotary- nut ball screw is described. On basis of restrictions and selected criterions solution of one size of rotary – nut ball screw with all the calculations.
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