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EN
The aim of the study was to present an experimental investigation of the influence of the RMF on mixing time. The obtained results suggest that the homogenization time for the tested experimental set-up depending on the frequency of the RMF can be worked out by means of the relationship between the dimensionless mixing time number and the Reynolds number. It was shown that the magnetic field can be applied successfully to mixing liquids.
2
Content available remote Method of evolutionary designing of FPGA-based controllers
EN
Controller design is a difficult and time consuming process. Moreover, high implementation accuracy of theoretically developed control algorithm causes high computational complexity and may result in inability of control system to work with selected time step. Short time step is often a necessary condition of correctness of control algorithm and finally of control system. These requirements may be fulfilled by use of the field programmable gate array (FPGA) as a implementation platform. However, in many cases designed controller is sensitive to inaccuracy due to limited resolution of input and output signals as well as of digital word used in implementation. All of these limitations should be taken into consideration in design stage. In this paper is proposed a method based on an evolutionary algorithm which takes into account mentioned limitations. As a result the process of controller design is performed easier and faster.
PL
Projektowanie regulatora jest trudnym i czasochłonnym procesem. Ponadto implementacja opracowanego teoretycznie algorytmu sterowania niejednokrotnie skutkuje wysoką złożonością obliczeniową. Może to skutkować brakiem możliwości pracy systemu sterowania z zadanym krokiem czasowym. Oprócz wspomnianych zjawisk występują problemy związane z rozdzielczością sygnałów wejściowych i wyjściowych jak i słowa cyfrowego użytego w implementacji realizowanej w na przykład układach programowalnych FPGA. Aby powstający system działał prawidłowo wszystkie te ograniczenia powinny być uwzględnione już na etapie projektowania. W artykule przedstawiona została metoda projektowania systemu regulacji bazująca na algorytmie ewolucyjnym. Metoda ta uwzględnia wspomniane ograniczenia oraz czyni trudny i czasochłonny proces projektowania regulatora łatwiejszym i szybszym.
EN
For many practical weakly nonlinear systems we have their approximated linear model. Its parameters are known or can be determined by one of typical identification procedures. The model obtained using these methods well describes the main features of the system’s dynamics. However, usually it has a low accuracy, which can be a result of the omission of many secondary phenomena in its description. In this paper we propose a new approach to the modelling of weakly nonlinear dynamic systems. In this approach we assume that the model of the weakly nonlinear system is composed of two parts: a linear term and a separate nonlinear correction term. The elements of the correction term are described by fuzzy rules which are designed in such a way as to minimize the inaccuracy resulting from the use of an approximate linear model. This gives us very rich possibilities for exploring and interpreting the operation of the modelled system. An important advantage of the proposed approach is a set of new interpretability criteria of the knowledge represented by fuzzy rules. Taking them into account in the process of automatic model selection allows us to reach a compromise between the accuracy of modelling and the readability of fuzzy rules.
PL
W pracy rozpatrzono hydrolizę białek serwatkowych z wykorzystaniem komercyjnych proteaz. Określono szybkość hydrolizy, przeanalizowano mechanizm reakcji oraz określono skład końcowy produktów. Uzyskano wysoki stopień hydrolizy białek serwatkowych. Wśród powstałych oligopeptydów są peptydy o właściwościach biologicznie czynnych. Najkorzystniejszy pod względem zastosowania rozkład frakcji uzyskano dla trypsyny (ponad 40% stanowią peptydy <1 kDa).
EN
Hydrolysis of whey proteins using commercial proteases is presented in the paper. The rate of hydrolysis and reaction mechanism are analyzed. The composition of final product was determined. A high degree of hydrolysis of whey proteins was obtained. Among the final products there are peptides which present the biologically active properties. The most preferred fraction distribution (more than 40% of peptides <1 kDa) was received for trypsin.
PL
mieszalniku wstęgowym. W badaniach użyto cząstek węgla aktywnego, a proces mielenia przeprowadzono dla wybranych prędkości obrotów mieszadła: 2; 50 oraz 100 obr min -1. Określono wpływ wybranych parametrów operacyjnych (prędkość obrotowa mieszadła, czas mielenia) na uzyskany skład ziarnowy produktu. Otrzymane wyniki umożliwiły ocenę efektywności prowadzonych prób mielenia.
EN
Experimental results dealing with the grinding process of granular material in a ribbon mixer are presented. Activated carbon particles were used in the research. Milling process was performed for the selected stirrer rotational frequencies: 2, 50 and 100 rpm min-1. An influence of selected operational parameters (stirrer rotational frequency, grinding time) on the size distribution of granular material is presented. The results enabled the assessment of grinding test efficiency.
EN
Purpose: The paper presents the results of the microstructural and magnetic examinations of Nd-Fe-B type magnets produced by the mechanical powder milling method and doped with tungsten. Design/methodology/approach: The effect of the grain size and addition of tungsten on the microstructure and magnetic properties of nanocrystalline alloys of the basic composition of Nd10Fe84B6, as produced by the method of mechanical alloying in the process of prolonged milling, was investigated in the study. Powders were subjected to milling for a duration ranging from 10 to 120 hours in an Ar protective atmosphere. Moreover tungsten was added to the base alloy that exhibited the best magnetic parameters. The tungsten content of alloys varied in a broad range from 0 to 33 at%. Findings: The examinations have shown that the grinding duration, for which the best magnetic properties are obtained, is 90 hours. Prolonged grinding has a significant effect on the grain size and microstructure refinement. The alloy addition in the form of tungsten, similarly as in the case of prolonged grinding, leads to a structure refinement. In the case of W addition, an increase in the coercive field, with a simultaneous decrease in the value of remanence and magnetic energy density (BH)max, is observed. Practical implications: Development of relatively cheap Nd10Fe84B6 magnets of good service properties. Originality/value: Determination of the effect of grain size and tungsten content on the magnetic properties and microstructure of the Nd-Fe-B magnets.
PL
Badania ichtiologiczne przeprowadzono w czterech ciekach: Jordance, Lubni, Krzemiennej i Rudziance, leżących na Pojezierzu Lubuskim, wchodzącym w skład Pojezierza Poznańskiego. Próby ryb pozyskiwano metodą elektropołowów na wyznaczonych stanowiskach. Ogółem na wszystkich rzekach odłowiono i oznaczono 175 osobników, reprezentujących 9 gatunków. Liczebność odłowionych ryb wyraźnie dzieliła badane cieki na: bardzo ubogie - Rudzianka (jeden gatunek), nieco zasobniejsze - Jordanka i Krzemienna, w których odnotowano po trzy gatunki ryb, osiągających niewielkie rozmiary ciała oraz najzasobniejszy - Lubnia, w której złowiono sześć gatunków ryb. Dominantami w biomasie ichtiofauny Lubni i Krzemiennej były szczupak (Esox lucius L.) i płoć (Rutilus rutilus L.), natomiast największy udział w biomasie ryb rzeki Jordanka miał śliz (Barbatula barbatula L.). Ichtiofauna badanych rzek była zdominowana przez gatunki fitofilne i psammofine, w warunkach jednoczesnego braku litofili. We wcześniejszych badaniach, przeprowadzonych przez SZABLIKOWSKIEGO i ZAPOLNIKA [1980], w ichtiofaunie Rudzianki oznaczono siedem gatunków ryb (w tym śliza i kozę - Cobitis taenia L.), w Krzemiennej pięć gatunków (w tym śliza), a w Jordance trzy gatunki: cierniczka (Pungitius pungitius L.), kozę i pstrąga potokowego (Salmo trutta m. fario L.). W Lubni skład ichtiofauny również uległ niekorzystnym zmianom: wśród odłowionych ryb nie występowały oznaczone we wcześniejszych badaniach koza czy kleń (Leuciscus cephalus L.) - gatunki typowo rzeczne. Zaobserwowane w ciągu ponad 20 lat niekorzystne zmiany w składzie i strukturze ichtiofauny badanych rzek wskazują na zubożenie siedlisk.
EN
Ichthyobiological studies were carried out in four rivers: Jordanka, Lubnia, Krzemienna and Rudzianka in Lubuskie Lakeland - a part of Poznańskie Lakeland. Fish samples were obtained by the electrofishing method in selected sites. In total, 175 fish individuals representing 9 species were caught and identified in all water courses. The number of caught fish distinctly differentiated the studied water courses into the very poor river - Rudzianka (only one species caught), and the richest rivers like the Jordanka and Krzemienna where three fish species were found in each. In the Lubnia, river, six fish species were caught. In the Lubnia and Krzemienna, the dominants in fish biomass were pike (Esox lucius L.) and roach (Rutilus rutilus L.), while the greatest fish biomass in the Jordanka river was produced by the stone loach (Barbatula barbatula L.). In the earlier study carried out by SZABLIKOWSKI and ZAPOLNIK [1980] in the Rudzianka River, seven fish species were caught (including the stone loach and the spined loach Cobitis taenia L.); in the Krzemienna River five species (including the stone loach), and in the Jordanka River - only three species: the ten-spined stickleback (Pungitius pungitius L.), the spined loach and the brown trout (Salmo trutta m. fario L.). The ichthyofauna composition in the Lubnia River had also changed unfavourably: none of the rheopilic species, like the spined loach or chub (Leuciscus cephalus L.), caught earlier was found in the present study. The fish fauna of the studied rivers was dominated by phytophilous and psammophilous species with a complete absence of lithophilous species. This fact confirms the impoverishment and contamination of the studied habitats.
PL
W artykule omówiono architekturę rozproszonego systemu sterowania obrabiarką numeryczną bazującego na sieci Ethernet Czasu Rzeczywistego. Zaproponowano innowacyjne rozwiązanie zapewniające maksymalne wykorzystanie pasma przepustowości standardu Fast Ethernet w trybie full duplex, przy zachowaniu rygorów czasu rzeczywistego. W takim rozwiązaniu, zaimplementowanym w układzie FPGA, możliwe jest uzyskanie wysokiej jakości pracy złożonego systemu napędowego przy zachowaniu niskich kosztów produkcji i serwisu maszyny.
EN
In this work a Real Time Ethernet based distributed control system for CNC machine tool was presented. A new method to maximize utilization of Ethernet throughput with full duplex mode was proposed. Such a system guarantee a hard real time performance and can be used to build a high quality and low cost complex CNC system.
9
Content available remote Habitat variability and fish species structure in the Kończak stream
EN
In the year 2008, studies on ichthyofauna were carried out in the Kończak stream. The stream was divided into four sections representing the variability of the water course. In each section, a research segment (100–150 meters long) was defined. In the ichthyofauna structure analysis, the indices of quantitative biocenotic domination and biomass were used. Furthermore, on the basis of the obtained data, the Shannon-Wiener indices of species diversity (H), as well as the abundance and the biomass (ABC index) were calculated. Altogether, in all research localities, 667 fish specimens were collected, with a total weight of 8,760 g and classified into 19 species. The caught fish were classified into 8 reproductive groups. Significant differences in the species composition and the number of fish were recorded between the particular sections. The number of species occurring in the studied sections oscillated between 2 and 17. The richest ichthyocenoses were recorded in the transitional and forest sections characterized by a comparatively small transformation of the habitats and good environmental conditions. In the remaining two sections, located in the middle and in the upper stream course, there was a distinct impoverishment of ichthyocenoses caused by the decreased attractiveness of the habitats.
10
Content available remote The evolution of microstructure in annealed LaFeSi-type alloys
EN
The evolution of microstructure and the phase constitution of the LaFe11.0Co0.8(Si0.4Al0.6)1.2 alloy in as-cast state and after subsequent annealing at 1323 K for 10, 20, 49 days was studied. In the LaFe11.0Co0.8(Si0.4 Al0.6)1.2 alloy after arc-melting, the dominant dendritic ?-Fe phase crystallizes, which is confirmed by X-ray diffraction. Annealing of the samples resulted in evolution of microstructure and the phase constitution. Prolonged annealing of the samples causes almost full homogenization of the alloy with the single-phase structure identified as La(Fe0.85Co0.06Si0.04Al0.05)13 phase of the NaZn13-type structure.
PL
W pracy określono gęstość energii ścian domenowych w kilku grupach jednoosiowych ferromagnetyków: UFe10-xNixSi2 (x=0, 2, 4); UFe12-xAlxSi2 (x=1, 6); R2Fe14B (R=Pr, Nd, Gd, Dy); RMn2Ge2 (R=La, Ce, Pr, Nd) oraz Sm2Fe17N3, stosując stereologiczną metodę Bodenbergera-Huberta. Magnetyczną strukturę domenową obserwowano wykorzystując metodę figur proszkowych (ferrofluid). Ujawniona struktura domenowa jest typowa dla magnesów o jednym kierunku łatwego namagnesowania i dużej wartości anizotropii magnetokrystalicznej. Wyznaczone wartości gestości energii ścian domenowych porównano z wynikami literaturowymi otrzymanymi innymi metodami i stwierdzono dobrą zgodność.
EN
In the paper domain wall energy density for some groups of uniaxial magnetic materials: UFe10-xNixSi2 (x=0, 2, 4), UFe12-xAlxSi2 (x=1, 6), R2Fe14B (R=Pr, Nd, Gd, Dy), RMn2Ge2 (R=La, Ce, Pr, Nd) and Sm2Fe17N3, was determined applying stereologic method of Bodenberger and Hubert. Magnetic domain structure was observed using the powder pattern method (ferrofluid). The domain structure observed is typical for materials with one easy direction of magnetization. The values of domain wall energy density were compared with literature data determined using other methods and a good agreement was stated.
EN
The effect of the contents of the magnetically hard and magnetically soft phases on the magnetic properties of Nd2Fe14B + alfa-Fe nanocrystalline magnets, as produced by the method of mechanical alloying, has been established. The phase composition of specimens was determined using X-ray diffractometry and Mössbauer spectroscopy. The Mössbauer examination showed that as the powder milling times increased, the content of the Nd2Fe14B phase increased from 42.8% (after the milling time of 10 h, with a grain size of 44.8 nm) to 66.3% (after the milling time of 48 h, with a grain size of 37.3 nm) and then decreased to 40.3% after 120 h of milling. On the other hand, the content of the magnetically soft phase alfa-Fe initially decreased (from 27.7%), reaching a minimum after the milling time of 48 h (17.4%) and then increasing to 36.9% after 120 h of milling.
13
Content available remote Structure and magnetic properties of powder soft magnetic materials
EN
Purpose: The paper presents influence of high-energy mechanical milling process, isothermal annealing and to a combination of these two technologies of cobalt base metallic glasses Co77Si11.5B11.5 on magnetic properties and their structure. Design/methodology/approach: The powder test piece obtained from the input amorphous ribbon in high-energy ball milling. The diffraction examinations and examinations of thin foils were made on the JEOL JEM 200CX transmission electron microscope. Observations of the structure of powders were made on the Opton DSM-940 scanning electron microscope. The X-ray tests were realized with the use of the XRD 7 SEIFERT-FPM diffractometer. Findings: analysis of the magnetic properties test results of the Co77Si11.5B11.5 powders obtained in the high-energy ball of milling process proved that the process causes significant decrease in the magnetic properties. The structure and magnetic properties of this material may be improved by means of a proper choice of parameters of this process as well as the final thermal treatment. Research limitations/implications: For the powders, further magnetical, structure and composition examinations are planed. Practical implications: The amorphous and nanocrystalline metal powders obtained by high-energy ball milling of metallic glasses feature an alternative to solid alloys and make it possible to obtain the ferromagnetic nanocomposites, whose shape and dimensions can be freely formed. Originality/value: The paper presents influence of parameters of the high-energy ball milling process on structure and magnetic properties of soft magnetic powder materials obtained in this technique. Results and a discussion of the influence of high energy mechanical milling process on particle size and their distribution as well as structure and magnetic properties of investigated samples is presented.
PL
Przedstawiono wyniki badań własności magnetycznych nanokrystalicznego materiału kompozytowego typu SILAMEŽ. Materiał kompozytowy uzyskano z zestalenia nanokrystalicznego proszku otrzymanego w procesie wysokoenergetycznego mielenia wstępnie skrystalizowanej taśmy amorficznej Co68Fe4Mo1Si13,5B13,5 (rys. 1) z polimerem silikonowym. Proszek metaliczny zmieszano z silikonowym polimerem w różnym stosunku objętościowym, a następnie zbadano wpływ udziału objętościowego proszku Co68Fe4Mo1Si13,5B13,5 na własności magnetyczne kompozytu. Przy większej zawartości metalicznego proszku cząstki Co68Fe4Mo1Si13,5B13,5 rozmieszczone są równomiernie w całej osnowie polimerowej. Lokalnie skupiska cząstek proszku (rys. 2) pojawiają się w kompozycie wraz ze zmniejszeniem objętości proszku. Własności magnetyczne nanokrystalicznego materiału kompozytowego, a przede wszystkim indukcja nasycenia Bs i koercja HC uzależnione są od udziału proszku metalicznego Co68Fe4Mo1Si13,5B13,5 w kompozycie i podwyższają się ze wzrostem udziału proszku. W publikacji przedstawiono wyniki badań struktury nanokrystalicznego proszku Co68Fe4Mo1Si13,5B13,5 oraz materiału kompozytowego SILAMEŽ, a także przebiegi pętli histerezy (rys. 3), podatności magnetycznej (rys. 5) oraz przenikalności i stratności magnetycznej kompozytu (tab. 1).
EN
Magnetic properties investigation results are presented in the paper of the SILAMEŽ type nanocrystalline composite material. The composite material was fabricated by solidification of the nanocrystalline powder obtained in the high energy milling of the preliminarily crystallised Co68Fe4Mo1Si13,5B13,5 (Fig. 1) amorphous ribbon with the silicone polymer. The metallic powder was mixed with the silicone polymer in various volume contents and next the effect was studied of the yolurne contents of the Co68Fe4Mo1Si13.5B13.5 powder on the magnetic properties of the composites. Particles of the Co68Fe4Mo1Si13,5B13,5 powder are distributed evenly in the composite in the entire polymer matrix with the higher fraction of the reinforcement material in the composite; whereas, with the reduction of the powder fraction, local clusters of the metallic powder occur (Fig. 2). Composites with the silicone polymer matrix are characteristic of the increase of saturation induction Bs and coercion field HC along with the increase of the volume contents of the Co68Fe4Mo1Si13,5B13,5 powder in the composite. The publication presents investigation results of the Co68Fe4Mo1Si13,5B13.5 nanocrystalline powder structure and of the SILAMEŽ composite material, runs of the hysteresis loop (Fig. 3), magnetic susceptibility (Fig. 5), as well as of the permeability and lossiness of the composite (Table 1).
EN
The investigation was carried out on nanocomposite Nd10Fe84-xWxB6 magnets with different tungsten content (from 0 to 33 at.%) produced by the mechanical alloying method. The alloys have a fine grained and highly porous structure. As tungsten is added the powder particles become progressively smaller and are distributed uniformly throughout the whole specimen volume. From the phase structure determination using X-ray diffraction, Moessbauer spectroscopy and transmission electron microscopy it has been found that with the increase of tungsten content in the magnets the amount of the magnetically hard Nd2Fe14B and the soft alpha-Fe phases decrease. Instead, paramagnetic phases appear. Moreover, the addition of tungsten to the basic composition results in a significant increase in coercivity jHc (from 260 to 1350 kA/m) and a reduction in both the remanence Br (from 0.95 to 0.24 T) and the maximum magnetic energy product (BH)max (from 80 to 13 kJ/cubic m).
PL
Celem badań było określenie wpływu, dodatku do pasz prebiotyku Fermato lub probiotyku Biosaf, na wzrost narybku karpia oraz wykorzystanie składników pokarmowych pasz. Pasze doświadczalne, z dodatkiem prebiotyku lub probiotyku, zostały wykonane jako diety izobiałkowe i izoenergetyczne. Przeprowadzono 50-dniowy test wzrokowy z udziałem narybku karpia. Ryby, otrzymujące pasze prebiotyczne lub probiotyczne, cechowały się istotnie wyższą, średnią jednostkową masą ciała w porównaniu do ryb z grupy kontrolnej (p<= 0,05). Najkorzystniejsze wartości współczynników pokarmowych pasz oraz wskaźnika wykorzystania białka paszowego odnotowano dla pasz z dodatkiem prebiotyku lub probiotyku, a różnice były statystycznie istotne w porównaniu z paszą kontrolną. Żywienie narybku karpia paszami, zawierającymi dodatek prebiotyku Fermato lub probiotyku Biosaf, skutkowało polepszeniem wskaźników chowu: optymalny dodatek prebiotyku wyniósł 3 g na jeden kilogram paszy, a optymalny dodatek prebiotyku ustalono na 1 g w kilogramie paszy (8.10/9 jtk drożdży w kg paszy).
EN
The studies have determined the effect of carp fry feeds with an addition of prebiotic Fermacto or probiotic Biosaf, on the growth and food conversion ratio in carp fry. Experimental feeds with the prebiotic or probiotic preparations were made as isonitric and isocaloric diets. A 50-day growth test with carp fry were carried out. The fish receiving the prebiotic or probiotic feeds showed significantly higher mean individual body weight ( p<=0,05) in comparison with the control group. The most favourable values of food conversion and protein efficiency ratio were recorder for feeds with prebiotic or probiotic addition and the differences were statistically different in comparison with the control feed. Feeding of carp fry with feeds containing an addition of Fermacto prebiotic or Biosaf probiotic improves the rearing results; the optimal addition of the prebiotic is 3 g of the preparation per one kilogram of feed, and the optimal addition of the probiotic is1 g of the preparation per one kilogram of feed (8x10/9 CFU kg/-1 of feed).
PL
W artykule porównano własności magnetyczne oraz mechaniczne toroidalnych rdzeni magnetycznie miękkich o osnowie polimerowej wzmacnianych nanokrystalicznymi proszkami stopów kobaltu. Proszki otrzymano w procesie wysokoenergetycznego mielenia amorficznej taśmy na osnowie kobaltu Co68Fe4Mo1Si13,5B13,5 wyżarzonej izotermicznie w atmosferze argonu przed mieleniem. Uzyskane wyniki porównano z własnościami magnetycznymi toroidalnych rdzeni wytworzonych z litych taśm. Ponadto przedstawiono wpływ warunków procesu wysokoenergetycznego mielenia na własności magnetycznie miękkie materiału proszkowego oraz wpływ udziału silikonowej osnowy na własności magnetyczne i mechaniczne rdzeni kompozytowych
EN
Magnetic and mechanical properties are compared in the paper of the toroidal magnetically soft cores with the polymer matrix reinforced with the nanocrystalline powders from cobalt alloys. The powders were obtained in the high energy milling of the Co68Fe4Mo1Si13,5B13,5 amorphous ribbon with the cobalt matrix isothermally annealed in the argon atmosphere before milling. The results obtained were compared with the magnetic properties of the toroidal cores fabricated from the solid ribbons. Moreover, the high energy milling process conditions effect on the soft magnetic properties of the powder material is presented, as well as the influence of the silicon matrix fraction on magnetic and mechanical properties of the composite cores. The compressed Co77Si11,5B11,5 powder compared to the loosely poured powder is characteristic of the higher saturation induction BS = 0.94 T. The lowest value of the saturation induction is demonstrated by the compressed powder annealed at the temperature of 560 degrees Celsius. It is also characteristic of the highest value of the coercion field Hc = 31497. Particles of the Co68Fe4Mo1Si13,5B13,5 powder are distributed evenly in the composite in the entire polymer matrix with the higher fraction of the reinforcement material in the composite; whereas, with the reduction of the powder fraction, local clusters of the metallic powder occur. Composites with the silicone polymer matrix are characteristic of the increase of saturation induction Bs and coercion field Hc along with the increase of the mass portion of the Co68Fe4Mo1Si13,5B13,5 powder in the composite. Tensile strength MPa and elongation E decrease with the mass portion increase of the metallic powder; whereas, the Young 's modulus and average modulus Eavg grow with the mass portion of the powder. The static compression test results confirm that along with the growing Co68Fe4Mo1Si13,5B13,5 powder portion, the ultimate tensile strength UTS increases and elongation decreases.
EN
The nanocomposite Nd2Fe14B/alpha-Fe magnets with different grain size produced by mechanical alloying were studied. The phase composition of the magnets was determined on the basis of X-ray diffraction and Moessbauer spectroscopy. It was stated that the alloy is composed of three phases (with different volume fraction depending on the milling time): the magnetically hard phase Nd2Fe14B and the magnetically soft phases alpha-Fe and Nd2Fe17. In metallographic examinations, the techniques of optical, scanning and transmission electron microscopy were employed. Moreover, magnetic properties were determined depending on milling time (grain size). Maximum magnetic properties were achieved in the magnet produced from powders obtained after 90 hours' milling, which were as follows: Jr=0,914 T; jHc=251.1 kA/m; Js=2.12 T and (BH)max=67.7 kJ/cubic m.
EN
The nanocomposite Nd2Fe14B/alpha-Fe magnets with different tungsten content (from 0 to 33 at. %) produced by mechanical alloying were examined. It was found that the magnetization process changes with increase of tungsten content in the material. In the alloy without tungsten coercivity mechanism is connected with the nucleation and growth of domains with opposite magnetization. With increase tungsten content in the alloy, pinning of the domain walls plays a more important role in the magnetization processes. Moreover, the changes in magnetic properties, such as coercive force jHc, remanence Br and energy product (BH)max depending on tungsten content in Nd2Fe14B/alpha-Fe magnets are reported.
PL
Wykonano badania dotyczące optymalizacji składu mieszanek paszowych dla karpi. Przetestowano cztery ekstrudowane mieszanki paszowe dla narybku i kroczka karpia, zawierające różne ziarna zbóż: jęczmień, pszenicę, pszenżyto, żyto. Przeprowadzono testy wzrostowe z udziałem narybku i kroczka karpia. Mieszanki paszowe przygotowane jako diety izoazotowe i izokaloryczne upostaciowano metodą bazotermiczną Pasze doświadczalne oceniano na podstawie cech fizycznych i chemicznych. Do oceny końcowych wyników testu wzrostowego wykorzystano następujące wskaźniki: przyrost masy ryb (WG), dobowy przyrost masy jednostkowej ryb (SGR), przeżywalność ryb (SR), współczynnik pokarmowy pasz (FCR), współczynnik wydajności wzrostowej białka (PER) oraz wskaźnik retencji białka paszowego (PR). Analizę statystyczną wyników doświadczenia przeprowadzono przy użyciu programu Statistica 5 PL. Najwyższy przyrost masy i tempo wzrostu uzyskano żywiąc karpie mieszanką paszową zawierającą pszenżyto, natomiast najkorzystniejsze wskaźniki wykorzystania składników pokarmowych paszy osiągnięto stosując mieszankę zawierającą pszenicę. Skarmianie pasz z udziałem innych gatunków zbóż (jęczmień lub żyto) powodowało niższe przyrosty masy ciała i gorsze wykorzystanie składników pokarmowych diet.
EN
The studies on common carp feeds optimization were conducted. Four extruded feeds for fry and two-year old carp are presented. They contain grains of different cereals (barley, wheat, triticale, rye). Growth tests with fry and two-year old carp were carried out. Feeds were prepared as isonitric and isocaloric diets formed into pellets by barothermal method. The experimental feeds were evaluated on the basis of physical and chemical characteristics. For the evaluation of the final results of the growth tests, the following indices were used: Fish Weight Gain (WG), Specific Growth Rate (SGR), Survival Rate (SR), Food Conversion Ratio (FCR), Protein Efficiency Ratio (PER) and Protein Retention (PR). Statistic analyses of the experimental results were carried out using Statistica 5 PL Program. The highest growth increment and growth rate were obtained in carps fed on feed containing triticale, while the best food conversion ratio was found in carps fed on feed containing wheat. Feed mixes containing other cereals (barley and rye) gave lower body mass increment and worse food conversion ratios.
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