34 research outputs found
Flood control measures in the Loučka Catchment
Bakalářská práce se zabývá protipovodňovou ochranou povodí říčky Loučky. Cílem je posouzení nutnosti doplnění protipovodňových opatřená v daném povodí. První polovina práce se zabývá průzkumem povodí a získáním podkladů k danému tématu. Druhá část práce se zabývá sestavením a aplikací srážkoodtokového modelu na řešení uvedeného problému. Pro schematizaci povodí byl použit program ArcGIS. Simulací srážkoodtokového procesu byly vypočteny kritické doby trvání náhradních intenzit deště a stanoveny N-leté průtoky. Byla vytipována kritická místa a posouzena na možný rozliv.This thesis deals with the river basin flood protection Loučka. The aim to assess the need tu supplement flood control measures in the watershed. The first half deals with exploration of river basin, providing geographic factors and obtaining information on the topic. The second part deals with the establishment and application of rainfall model to solve the problem. For schematisation basin was used ArcGIS program. Rainfall simulation process were calculated critical duration of rainfall intensity and spare set of N-year flows. It was by searching for critical points and assessed for possible overflow.
Effect of minimal disease in a herd on reproductive parameters of sows
The aim of this study was evaluation of reproductive performance in sows from herds with minimal disease. Total number of 40 sows were included in the observation and evaluated from the 1st to the 4th parity. The highest reproductive performance was recorded at the 3rd parity. Statistically significant difference (P < 0.05) was found between the 1st and the 3rd parity and highly statistically significant difference (P < 0.01) was recorded between the 2nd and the 3rd parity in number of live-born piglets. Comparison of numbers of stillborn piglets showed statistically significant difference (P < 0.05) between the mean values of the 1st and the 4th parity. The results also showed highly statistically significant difference (P < 0.01) in number of reared piglets between the 3rd and the 4th parity. The conclusions of this study indicate that creation and maintenance of herds of sows with high health status lead to excellent results in the area of pig reproduction.O
Retention Reservoir Design in the Police Cadastr
Diplomová práce se zabývá protipovodňovou ochranou povodí říčky Loučky. Cílem je posouzení nutnosti doplnění protipovodňových opatření v daném povodí. První část práce se zabývá průzkumem povodí, získáním podkladů k danému tématu, sestavením a aplikací srážkoodtokového modelu na řešení uvedeného problému. Druhá část práce se zabývá zlepšením protipovodňové ochrany ve vytipovaných kritických místech navržením soustavy nádrží s retenčním účinkem a zvýšením kapacity koryta. Pro schematizaci povodí byl použit program ArcGIS, simulace srážkoodtokového procesu byla provedena v programu Hydrog.This thesis deals with the river basin flood protection Loučka. The goal of the thesis is to assess the need of flood control measures supplement in the watershed. The first part deals with exploration of river basin, acquiring geographic factors and obtaining information about the topic, establishment and application of rainfall model used for solving the problem. The second part deals with improving of flood protection at critical selected places by using design of reservoir system with retention effect and by increasing river basin capacity. For basin schematisation was used ArcGIS program and the simulation of rainfall-runoff process was made by Hydrog program.
Vliv zkrmování konjugované kyseliny linolové na produkční užitkovost prasniček
The aim of this study was to evaluate whether the supplementation of conjugated linoleic acid (CLA) in feed mixtures influences the parameters of production performance in gilts. The experimental work was realized in operating conditions of a production pig farm. Total number of 40 gilts (20 gilts in control group and 20 gilts in experimental group) of hybrid combination Czech Large White x Czech Landrace (CLW x CL) were included in the observation. During the experiment the gilts kept for rearing were fed with a control compound feed and an experimental compound feed suplemented with 2% of CLA for the time of 65 days. At the beginning and the end of the experiment, performance tests were conducted in accordance with the methodology of ČSN 466164 on Performance and progeny testing in pigs. The gilts in the experimental group reached higher weight 148.05 ± 15.80 kg versus 135.75 ± 17.60 kg (P < 0.05) at the end of the test. The evaluation of mean achieved daily gain for the time from birth to the end of the test confirmed higher values for the gilts in the experimental group 586.05 ± 66.64 g*day-1 against 539.00 ± 62.19 g*day-1 for the gilts in the control group (P < 0.05). Within other parameters of efficiency in gilts, i.e. lean meat content, backfat thickness and depth of MLLT muscle, no significant influence of CLA on their phenotypic manifestation was found. The results of study indicate, that the supplementation of feed mixture for rearing gilts with conjugated linoleic acid can influence the growth ability of gilts.Cílem práce bylo vyhodnotit, zda přídavek konjugované kyseliny linolové (CLA) do krmné směsi ovlivní parametry produkční užitkovosti prasniček. Pokus byl realizován v provozních podmínkách užitkového chovu prasat. Do sledování bylo zařazeno celkem 40 prasniček hybridní kombinace České bílé ušlechtilé x Česká Landrase, přičemž 20 prasniček bylo v kontrolní a 20 prasniček v pokusné skupině. Během sledování byly prasničky ustájeny v odchovně a krmeny kontrolní krmnou směsí a pokusnou směsí s přídavkem 2% CLA, a to po dobu 65 dnů. Na začátku a na konci pokusu byla provedena kontrola užitkovosti prasat dle metodiky České státní normy 466164. Prasničky pokusné skupiny dosáhly na konci testu vyšší hmotnosti 148,05 ± 15,80 kg oproti 135,75 ± 17,60 kg u skupiny kontrolní (P < 0,05). Vyhodnocení průměrného denní přírůstku od narození do konce testu prokázalo vyšší hodnotu u prasniček pokusné skupiny 586,05 ± 66,64 g*den-1 oproti 539,00 ± 6219 g*den-1 u skupiny kontrolní (P < 0,05). V rámci ostatních parametrů produkční užitkovosti prasniček, tj. u podílu libového masa, výšky hřbetního tuku a hloubky MLLT, nebyl zjištěn vliv CLA na jejich fenotypový projev. Získané výsledky ukazují, že přídavek konjugované kyseliny linolové do krmné směsi prasniček během odchovu může ovlivnit jejich růstovou schopnost
The effect of duroc and pietrain boars on growth ability of piglets
The aim of the experiment was to evaluate the effect of Duroc, Pietrain and Duroc x Pietrain terminal boars on individual live weight of piglets and average daily gain of piglets from birth to weaning. The effect of sex was also taken into account in the observation. A total of 306 piglets were evaluated. The experiment proved, that terminal boar significantly affects (p < 0.001) birth weight of piglets, their live weight at the age of 14 days and at weaning. Statistically significant effect of terminal boar was also proved for average daily gain from birth to the age of 14 days and average daily gain from birth to weaning. As demonstrated, the piglets of Duroc and Pietrain boars reached higher live weights in all the observed intervals than the piglets of Duroc x Pietrain hybrid combination boar. The same trend was observed for the values of average daily gain in piglets.O
Experimental evaluation of Tusi couple based energy harvester for scavenging power from human motion
This paper deals with the experimental performance evaluation of the prototype of a novel inertial energy harvester based on Tusi couple mechanism. The harvester was developed as an autonomous power source for environments with very low frequency and magnitude of mechanical vibrations available. The experiments were conducted using human body during different activities as a source of mechanical excitation, with the prospect of using the harvester for powering up future wearable electronic devices. Four different locations on a single measurement specimen were picked for the harvester placement-back of the head, belt, wrist and ankle. Measurements in each location comprised of walking on a straight and level path at natural speed, walking up and down the stairs, jumping, running, and location-specific activities that were expected to provide significant output power. The measured average output power of the device with dimensions 50x50x20 mm on empirically selected 2 k electrical load reached up to 6.5 mW, obtained with the device attached to the ankle while shaking the leg
Prediction of position-dependent stability lobes based on reduced virtual model
The stability of a machining process is directly affected by the dynamic response between the tool and the workpiece. However, as the tool moves along the path, the dynamic stiffness of the machine tool changes. To determine the position-dependent dynamic stiffness accurately, a computationally efficient methodology based on a complex virtual model is presented. The virtual model is assembled using Finite Element Method and is effectively reduced via Component Mode Synthesis and transformation to a State-Space Multi-Input-Multi-Output system. Combination of these techniques allows time-efficient response simulations with significantly less computational effort than the conventional full Finite Element models. Furthermore, they describe the behaviour of the complex structure more accurately opposed to the commonly used models based on a simple 1 Degree-of-Freedom systems. The reduced model is used to simulate dynamic response of the structure to a cutting force during operation. A response is measured on an existing machine to modify the virtual model by incorporating fuzzy parameters, such as damping. The stability regions are calculated for variable positions, resulting in position-dependent lobe diagrams. The presented approach can be used to create a map of stable zones to predict and prevent unstable behaviour during operation
Experimentally Verified Analytical Models of Piezoelectric Cantilevers in Different Design Configurations
This paper deals with analytical modelling of piezoelectric energy harvesting systems for generating useful electricity from ambient vibrations and comparing the usefulness of materials commonly used in designing such harvesters for energy harvesting applications. The kinetic energy harvesters have the potential to be used as an autonomous source of energy for wireless applications. Here in this paper, the considered energy harvesting device is designed as a piezoelectric cantilever beam with different piezoelectric materials in both bimorph and unimorph configurations. For both these configurations a single degree-of-freedom model of a kinematically excited cantilever with a full and partial electrode length respecting the dimensions of added tip mass is derived. The analytical model is based on Euler-Bernoulli beam theory and its output is successfully verified with available experimental results of piezoelectric energy harvesters in three different configurations. The electrical output of the derived model for the three different materials (PZT-5A, PZZN-PLZT and PVDF) and design configurations is in accordance with lab measurements which are presented in the paper. Therefore, this model can be used for predicting the amount of harvested power in a particular vibratory environment. Finally, the derived analytical model was used to compare the energy harvesting effectiveness of the three considered materials for both simple harmonic excitation and random vibrations of the corresponding harvesters. The comparison revealed that both PZT-5A and PZZN-PLZT are an excellent choice for energy harvesting purposes thanks to high electrical power output, whereas PVDF should be used only for sensing applications due to low harvested electrical power output
Energy harvesting from passing train as source of energy for autonomous trackside objects
This paper deals with an energy harvesting review and analysis of an ambient mechanical energy on a trackside during a passing of a train. Trains provide very high level of vibration and deformation which could be converted into useful electricity. Due to maintenance and safety reasons a rail trackside includes sensing systems and number of sensor nodes is increased for modern transportation. Recent development of modern communication and ultra-low power electronics allows to use energy harvesting systems as autonomous source of electrical energy for these trackside objects. Main aim of this paper is model-based design of proposed vibration energy harvesting systems inside sleeper and predict harvested power during the train passing. Measurements of passing train is used as input for simulation models and harvested power is calculated. This simulation of proposed energy harvesting device is very useful for future design
Electro-mechanical analysis of a multilayer piezoelectric cantilever energy harvester upon harmonic vibrations
This paper addresses an important issue of the individual layer thickness influence in a multilayer piezo composite on electro-mechanical energy conversion. The use of energy harvesting systems seems to be very promising for applications such as ultra-low power electronics, sensors and wireless communication. The energy converters are often disabled due to a failure of the piezo layer caused by an excessive deformation/stresses occurring upon the operation. It is thus desirable to increase both reliability and efficiency of the electromechanical conversion as compared to standard concepts. The proposed model of the piezoelectric vibration energy harvester is based on a multilayer beam design with active piezo and protective ceramic layers. This paper presents results of a comparative study of an analytical and numerical approach used for the electro-mechanical simulations of the multilayer energy harvesting systems. Development of the functional analytical model is crucial for the further optimization of new (smart material based) energy harvesting systems, since it provides much faster response than the numerical model