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Tytuł:
Estimation of Asymmetry in Head Related Transfer Functions
Autorzy:
Jasiński, Maciej
Żera, Jan
Powiązania:
https://bibliotekanauki.pl/articles/2055229.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
acoustics
sound processing
virtual reality
spatial sound
Head Related Transfer Functions
Opis:
The individual Head-Related Transfer Functions (HRTFs) typically show large left-right ear differences. This work evaluates HRTF left-right differences by means of the rms measure called the Root Mean Square Difference (RMSD). The RMSD was calculated for HRTFs measured with the participation of a group of 15 subjects in our laboratory, for the HRTFs taken from the LISTEN database and for the acoustic manikin. The results showed that the RMSD varies in relation to the frequency and as expected is small for more symmetrical HRTFs at low frequencies (0.3÷1 kHz). For higher frequency bands (1÷5 kHz and above 5 kHz), the left-right differences are higher as an effect of the complex filtering caused by anatomical shape of the head and the pinnae. Results obtained for the subjects and for data taken from the LISTEN database were similar, whereas different for the acoustic manikin. This means that measurements with the use of the manikin cannot be considered as perfect average representation of the results obtained or people. The method and results of this study may be useful in assessing the symmetry of the HRTFs, and further analysis and improvement of how to considered the HRTFs individualization and personalization algorithms.
Źródło:
International Journal of Electronics and Telecommunications; 2022, 68, 2; 193--200
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Head-Related Transfer Function Selection Using Neural Networks
Autorzy:
Yao, S.-N.
Collins, T.
Liang, C.
Powiązania:
https://bibliotekanauki.pl/articles/176307.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
head-related transfer function
neural networks
localisation
music
audio
anthropometry
pinna
Opis:
In binaural audio systems, for an optimal virtual acoustic space a set of head-related transfer functions (HRTFs) should be used that closely matches the listener’s ones. This study aims to select the most appropriate HRTF dataset from a large database for users without the need for extensive listening tests. Currently, there is no way to reliably reduce the number of datasets to a smaller, more manageable number without risking discarding potentially good matches. A neural network that estimates the appropriateness of HRTF datasets based on input vectors of anthropometric measurements is proposed. The shapes and sizes of listeners’ heads and pinnas were measured using digital photography; the measured anthropometric parameters form the feature vectors used by the neural network. A graphical user interface (GUI) was developed for participants to listen to music transformed using different HRTFs and to evaluate the fitness of each HRTF dataset. The listening scores recorded were the target outputs used to train the neural networks. The aim was to learn a mapping between anthropometric parameters and listener’s perception scores. Experimental validations were performed on 30 subjects. It is demonstrated that the proposed system produces a much more reliable HRTF selection than previously used methods.
Źródło:
Archives of Acoustics; 2017, 42, 3; 365-373
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of radial flow impeller balance holes on the net positive suction head for rotodynamic pumps
Autorzy:
Karaśkiewicz, K.
Złoty, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/175487.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
balance holes
net positive suction head (NPSH)
centrifugal pumps
cavitation
Opis:
The influence of balance holes of rotodynamic pumps on the net positive suction head is not fully clear. The lack of available information on the subject leads to the situations when deterioration in suction properties of the pump due to the presence of balance holes is recognized during pump test phase. Usually some holes are arbitrarily plugged. The paper analyses the influence of balance holes on net positive suction head characteristics. The measurement data are presented.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2017, 136; 47-54
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Engineering design of low-head Kaplan hydraulic turbine blades using the inverse problem method
Autorzy:
Krzemianowski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/200629.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
inverse method
hydraulic turbine blade design
low-head Kaplan turbine
curvilinear coordinate system
Christoffel symbols
Opis:
The paper concerns the engineering design of guide vane and runner blades of hydraulic turbines using the inverse problem on the basis of the definition of a velocity hodograph, which is based on Wu’s theory [1, 2]. The design concerns the low-head double-regulated axial Kaplan turbine model characterized by a very high specific speed. The three-dimensional surfaces of turbine blades are based on meridional geometry that is determined in advance and, additionally, the distribution of streamlines must also be defined. The principles of the method applied for the hydraulic turbine and related to its conservation equations are also presented. The conservation equations are written in a curvilinear coordinate system, which adjusts to streamlines by means of the Christoffel symbols. This leads to significant simplification of the computations and generates fast results of three-dimensional blade surfaces. Then, the solution can be found using the method of characteristics. To assess usefulness of the design and robustness of the method, numerical and experimental investigations in a wide range of operations were carried out. Afterwards, the so-called shell characteristics were determined by means of experiments, which allowed to evaluate the method for application to the low-head (1.5 m) Kaplan hydraulic turbine model with the kinematic specific speed (»260). The numerical and experimental results show the successful usage of the method and it can be concluded that it will be useful in designing other types of Kaplan and Francis turbine blades with different specific speeds.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 6; 1133-1147
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Components of quantitative resistance in barley plants to Fusarium head blight infection determined using three in vitro assays
Autorzy:
Sakr, N.
Powiązania:
https://bibliotekanauki.pl/articles/66494.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
quantitative resistance
barley plant
Fusarium
head blight
plant infection
determination
detached leaf
Opis:
Quantitative resistance in barley to four Fusarium head blight (FHB) species was investigated in vitro. Nine components involved in three assays (detached leaf, modified Petridish and seedling tests) were compared on two widely grown Syrian barley cultivars: Arabi Aswad (AS) and Arabi Abiad (AB). On AB, inoculation with FHB species resulted in a significantly shorter latent period and larger lesion length of detached leaf inoculation, more standardized area under disease progress curve (AUDPCstandard) of modified Petridish inoculation and a higher percentage of infected seedlings of pin-point inoculation than on AS. The latent period of AB was 14.89% less than AS, lesion length of AS was 6.01% less than AB, AUDPCstandard of AS was 17.07% less than AB and the percentage of infected seedlings of AS was 4.87% less than AB. Inoculation with FHB species resulted in no significant differences in the other five components measured: incubation period of detached leaf inoculation, germination rate reduction and coleoptile length reduction of modified Petridish inoculation, percentage of infected seedlings of foliar-spraying inoculation and lesion length of clip-dipping inoculation. AS was more resistant to in vitro FHB infection than AB. The latent period and AUDPCstandard recorded the highest values compared with the lowest values for lesion length and percentage of infected seedlings. It seems that measurement of the latent period and AUDPCstandard may be useful in identifying barley cultivars which are highly susceptible or resistant to FHB at early stages.
Źródło:
Journal of Plant Protection Research; 2018, 58, 2
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of a Head Movement Navigation System for Mobile Telepresence Robot Using Open source Electronics Software and Hardware
Autorzy:
Wee, Tan Jia
Wahid, Herman
Powiązania:
https://bibliotekanauki.pl/articles/1844566.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
telepresence
head movement control
real-time
video streaming
Bluetooth communication
Opis:
Head movement is frequently associated with human motion navigation, and an indispensable aspect of how humans interact with the surrounding environment. In spite of that, the incorporation of head motion and navigation is more often used in the VR (Virtual Reality) environment than the physical environment. This study aims to develop a robot car capable of simple teleoperation, incorporated with telepresence and head movement control for an on-robot real-time head motion mimicking mechanism and directional control, in attempt to provide users the experience of an avatar-like third person’s point of view amid the physical environment. The design consists of three processes running in parallel; Motion JPEG (MJPEG) live streaming to html-Site via local server, Bluetooth communication, and the corresponding movements for the head motion mimicking mechanism and motors which acts in accordance to head motion as captured by the Attitude Sensor and apparent command issued by the user. The design serves its purpose of demonstration with the usage of basic components and is not aimed to provide nor research with regards to user experience.
Źródło:
International Journal of Electronics and Telecommunications; 2021, 67, 3; 379-384
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exploitation research of trams head lighting - low beam lights
Badania eksploatacyjne oświetlenia głównego tramwaju - świateł mijania
Autorzy:
Tomczuk, P.
Powiązania:
https://bibliotekanauki.pl/articles/224335.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
oświetlenie tramwaju
światła mijania
badania eksploatacyjne
tram's head lighting
low beam lights
CCD camera
luminance
Opis:
Appropriately shaped light beam conditions correct visibility from a tram driver's seat and makes it easier to assess properly road situations connected with behaviour of other road traffic participants. The article presents the current state of tram's front lighting. Projectors and reflectors have been tested together with the sources of light currently exploited in tram vehicles. The present photometric requirements as well as the legal state concerning exploitation of lighting in trams have been described. Qualitative analysis has been conducted of currently used light beams of low beam lights with the use of image analyzer of CCD camera for luminance measurement. A method of luminance measurement on photometric screen has been described. Comparative results have been presented of luminance measurement in measurement points and zones on the borderline of light and shade, and on the glare line of a tram driver coming from the opposite direction.
Odpowiednio ukształtowana wiązka świetlna warunkuje właściwą widzialność z miejsca motorniczego i ułatwia właściwą ocenę sytuacji drogowych związanych z zachowaniem się innych uczestników ruchu drogowego. W artykule zaprezentowany został obecny stan oświetlenia przedniego tramwajów. Przebadano projektory i reflektory wraz ze źródłami światła eksploatowanymi obecnie w pojazdach tramwajowych. Opisano aktualne wymagania fotometryczne oraz stan prawny dotyczący eksploatacji oświetlenia w tramwajach. Dokonana została jakościowa analiza wykorzystywanych obecnie wiązek świetlnych świateł mijania z zastosowaniem analizatora obrazu kamery CCD do pomiaru luminancji. Opisano metodę pomiaru luminancji na ekranie fotometrycznym. Zaprezentowano wyniki porównawcze pomiarów luminancji w punktach i strefach pomiarowych, na granicy światła i cienia oraz na linii blasku dochodzącego do motorniczego z naprzeciwka.
Źródło:
Archives of Transport; 2010, 22, 4; 477-494
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pathogenicity and quantitative resistance in Mediterranean durum and bread wheat cultivars of Syrian origin towards Fusarium head blight agents under controlled conditions
Autorzy:
Sakr, N.
Powiązania:
https://bibliotekanauki.pl/articles/2084875.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Fusarium head blight (FHB)
pathogenic variation
Triticum aestivum
wheat resistance
Triticum durum
Opis:
Although Syrian high-yielding wheat cultivars grown under Mediterranean conditions include acceptable levels of resistance to biotic constraints, little is known about their susceptibility to Fusarium head blight (FHB), a harmful disease of wheat cultivation worldwide. The capacity of 16 fungal isolates of four FHB species to confer the disease on spikes and spikelets of six widely grown old and modern Syrian durum and bread wheat cultivars with known in vitro quantitative resistance to FHB was evaluated. Quantitative traits were visually assessed using spray and point inoculations for determining disease development rates, disease incidence (DI) and disease severity (DS) under controlled conditions. Differences in pathogenicity and susceptibility among wheat cultivars were observed, emphasizing the need for breeders to include aggressive isolates or a mixture of isolates representative of the FHB diversity in their screenings for selection of disease resistant cultivars. Bread wheat cultivars showed lower levels of spike and spikelet damage than durum cultivars regardless of the date of cultivar release. Overall, the six wheat cultivars expressed acceptable resistance levels to initial fungal infection and fungal spread. Quantitative traits showed significant correlation with previous standardized area under disease progress curve (AUDPCstandard) data generated in vitro. Thus, the predictive ability of AUDPCstandard appears to be crucial in assessing pathogenicity and resistance in adult wheat plants under controlled conditions. While in the Mediterranean countries the risk of disease is progressively increasing, the preliminary data in this report adds to our knowledge about four FHB species pathogenicity on a Syrian scale, where the environment is quite similar to some Mediterranean wheat growing areas, and show that Syrian cultivars could be new resistant donors with favorable agronomical characteristics in FHB-wheat breeding programs.
Źródło:
Journal of Plant Protection Research; 2019, 59, 4; 451-464
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Subjective Evaluation of Three Headphone-Based Virtual Sound Source Positioning Methods Including Differential Head-Related Transfer Function
Autorzy:
Storek, D.
Rund, F.
Marsalek, P.
Powiązania:
https://bibliotekanauki.pl/articles/176959.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
virtual positioning
virtual reality
positioning method
positioning algorithm
head-related transfer function
amplitude panning
Opis:
This paper analyses the performance of Differential Head-Related Transfer Function (DHRTF), an alternative transfer function for headphone-based virtual sound source positioning within a horizontal plane. This experimental one-channel function is used to reduce processing and avoid timbre affection while preserving signal features important for sound localisation. The use of positioning algorithm employing the DHRTF is compared to two other common positioning methods: amplitude panning and HRTF processing. Results of theoretical comparison and quality assessment of the methods by subjective listening tests are presented. The tests focus on distinctive aspects of the positioning methods: spatial impression, timbre affection, and loudness fluctuations. The results show that the DHRTF positioning method is applicable with very promising performance; it avoids perceptible channel coloration that occurs within the HRTF method, and it delivers spatial impression more successfully than the simple amplitude panning method.
Źródło:
Archives of Acoustics; 2016, 41, 3; 437-447
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stability of an ellipsoidal head with a central nozzle under axial load
Stateczność dna elipsoidalnego z króćcem środkowym pod obciążeniem osiowym
Autorzy:
Jasion, P.
Magnucki, K.
Powiązania:
https://bibliotekanauki.pl/articles/231424.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
zbiornik ciśnieniowy
dno elipsoidalne
stateczność
wyboczenie
pressure vessel
ellipsoidal head
stability
buckling
Opis:
The subject of the numerical investigation is an ellipsoidal head with a central (axis-symmetrical) nozzle. The nozzle is loaded by axial load force. The ellipsoidal head is under axial-symmetrical compression load. The numerical FEM model is elaborated. The calculation will provide the critical loads and equilibrium paths for the sample head. The investigation will measure the influence of the diameter of the nozzle on the critical state of the ellipsoidal head.
Praca poświęcona jest analizie stateczności dna elipsoidalnego będącego typowym elementem zbiorników ciśnieniowych. Dno zakończone jest króćcem obciążonym siłą osiową ściskającą lub rozciągającą. Przeanalizowano wpływ średnicy króćca na wartość obciążenia krytycznego, postać wyboczenia oraz na przebieg ścieżki równowagi dna.
Źródło:
Archives of Civil Engineering; 2015, 61, 2; 89-98
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fusarium head blight (FHB) and Fusarium spp. on grain of spring wheat cultivars grown in Poland
Autorzy:
Lenc, L.
Czecholinski, G.
Wyczling, D.
Turow, T.
Kazmierczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/65227.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Fusarium head blight
Fusarium
grain
wheat
spring wheat
susceptibility
plant cultivar
Polska
Opis:
Eighteen spring wheat cultivars, recommended for commercial production in northern Poland, were assessed for Fusarium head blight (FHB) in natural non-epidemic conditions, from 2011 to 2013. Assessment was based on FHB incidence (proportion of heads with symptoms), disease severity (DS; proportion of bleached spikelets per head), proportion of Fusarium damaged kernels (FDK), and spectrum of Fusarium spp. colonising the kernels. Fusarium head blight incidence and DS often differed significantly among cultivars and years. There was a strong positive correlation between FHB incidence and DS. Fusarium head blight incidence and DS were not correlated with the June–July temperatures, and were only occasionally correlated with the total June–July rainfall. There was a weak positive correlation between FHB incidence and proportion of FDK. There was a strong positive correlation between DS and proportion of FDK. The cultivar affected colonisation of kernels by Fusarium spp. Fusarium poae was the FHB pathogen isolated most often. Fusarium poae colonised 6.0% of the kernels, on average, but up to 12.0% on individual cultivars. Other Fusarium species were less frequent: F. avenaceum in 5.6% of kernels, F. culmorum in 5.3%, F. tricinctum in 2.8%, F. graminearum in 1.5%, and F. sporotrichioides in 1.2%. Fusarium equiseti occurred sporadically. The importance of F. poae in the FHB complex is emphasised. All cultivars expressed ‘moderate FHB resistance’ if evaluated according to FHB incidence. Cultivars Arabella, Izera, Kandela, Monsun, Ostka Smolicka, and Struna expressed ‘moderate susceptibility’, and Bombona, Hewilla, Katoda, KWS Torridon, Łagwa, Nawra, Parabola, Radocha, SMH 87, Trappe, Tybalt, and Waluta expressed ‘susceptibility’ if evaluated by the proportion of FDK. Cultivars differed within the ‘moderately resistant’, ‘moderately susceptible’, and ‘susceptible’ categories. Cultivars Arabella, Izera, Kandela, Monsun, Ostka Smolicka, and Struna were the most promising and their resistance traits may be useful in FHB management.
Źródło:
Journal of Plant Protection Research; 2015, 55, 3
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of large-scale streamlined head cars of high-speed trains and aerodynamic drag calculation
Autorzy:
Wu, Z.
Yang, E.
Ding, W.
Powiązania:
https://bibliotekanauki.pl/articles/224065.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high speed train
NURBS
aerodynamic drag
streamlined head car
numerical simulation
pociąg ekspresowy
opór aerodynamiczny
symulacja numeryczna
Opis:
Aerodynamic drag plays an important role in high-speed trains, and how to reduce the aerodynamic drag is one of the most important research subjects related to modern railway systems. This paper investigates a design method for large-scale streamlined head cars of high-speed trains by adopting NURBS theory according to the outer surface characteristics of trains. This method first created the main control lines of the driver cab by inputting control point coordinates; then, auxiliary control lines were added to the main ones. Finally, the reticular region formed by the main control lines and auxiliary ones were filled. The head car was assembled with the driver cab and sightseeing car in a virtual environment. The numerical simulation of train flow field was completed through definition of geometric models, boundary conditions, and space discretization. The calculation results show that the aerodynamic drag of the high-speed train with large-scale streamlined head car decreases by approximately 49.3% within the 50-300 km/h speed range compared with that of the quasi-streamlined high-speed train. This study reveals that the high-speed train with large-scale streamlined head car could achieve the purpose of reducing running aerodynamic drag and saving energy, and aims to provide technical support for the subsequent process design and production control of high-speed train head cars.
Źródło:
Archives of Transport; 2017, 44, 4; 89-97
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of resistance and the role of some defense responses in wheat cultivars to Fusarium head blight
Autorzy:
Khaledi, N.
Taheri, P.
Falahati-Rastegar, M.
Powiązania:
https://bibliotekanauki.pl/articles/66757.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
resistance
defense response
wheat
Triticum aestivum
plant cultivar
Fusarium head blight
Fusarium culmorum
Fusarium graminearum
plant disease
Opis:
Fusarium graminearum and F. culmorum are the causal agents of Fusarium head blight (FHB) in cereal crops worldwide. Application of resistant cultivars is the most effective and economic method for management of FHB and reducing mycotoxin production in wheat. Understanding the physiological and biochemical mechanisms involved in basal resistance of wheat to FHB disease is limited. In this research, after screening resistance levels of eighteen wheat cultivars planted in Iran, Gaskozhen and Falat were identified as partially resistant and susceptible wheat cultivars against Fusarium spp., respectively. Also, we investigated the role of hydroxyl radical (OH−), nitric oxide (NO), callose deposition, lipid peroxidation and protein content in basal resistance of wheat to the hemi-biotrophic and necrotrophic Fusarium species causing FHB. Nitric oxide as a signaling molecule may be involved in physiological and defensive processes in plants. Our results showed that NO generation increased in seedlings and spikes of wheat cultivars after inoculation with Fusarium species. We observed earlier and stronger callose deposition at early time points after infection by Fusarium spp. isolates than in non-infected plants, which was positively related to the resistance levels in wheat cultivars. Higher levels of OH− and malondialdehyde (MDA) accumulation (as a marker of lipid peroxidation) were observed in the Falat than in the Gaskozhen cultivar, under non-infected and infected conditions. So, estimation of lipid peroxidation could be useful to evaluate cultivars’ susceptibility. These findings can provide novel insights for better recognition of physiological and biochemical markers of FHB resistance, which could be used for rapid screening of resistance levels in wheat cultivars against this destructive fungal disease.
Źródło:
Journal of Plant Protection Research; 2017, 57, 4
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new generation mining head with disc tool of complex trajectory
Głowica urabiająca nowej generacji z narzędziami dyskowymi o złożonej trajektorii
Autorzy:
Gospodarczyk, P.
Kotwica, K.
Stopka, G.
Powiązania:
https://bibliotekanauki.pl/articles/219820.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
kombajn chodnikowy
urabianie
skała zwięzła
głowica urabiająca
roadheader
mining
hard rock
cutting head
Opis:
In Polish underground mining plenty of dog headings are drilled with mechanical methods with the use of arm roadheaders equipped with milling units. Cutting tools applied on the units – rotary tangent bits in unfavourable mining and geological conditions or improper work conditions are affected by an accelerated wear process. It influences the speed and costs of drilling such excavations. The article presents a new and innovative solution of a mining head with asymmetric disc tools of complex trajectory elaborated at the Department of Mining, Dressing and Transport Machines, AGH University of Science and Technology, Krakow as an alternative for standard milling units. Advantages of the applied mining method using so called back incision were described as well as principles of construction and work of the suggested solution of the head. In order to work out a construction of the head prototype it was necessary to determine principles and guidelines based on laboratory tests. A construction of a specially prepared laboratory stand for examination of disc tools of complex trajectory, planned research methodology, course of tests and obtained results were presented. An analysis of the results allowed determining the above listed principles and guidelines for a construction of a prototype head. They were the base to work out, with cooperation of the REMAG Ltd Company in Katowice, a technical project of a new head solution, adapted for mounting on the arm of a medium arm roadheader KR 150. A constructed head underwent tests on a research stand on the REMAG testing area and received positive preliminary tests results.
W polskim górnictwie podziemnym bardzo duża liczba wyrobisk korytarzowych drążona jest metodami mechanicznymi z wykorzystaniem ramionowych kombajnów chodnikowych, wyposażonych w organy frezujące. Stosowane na tych organach narzędzia skrawające – noże styczno-obrotowe, w niekorzystnych warunkach górniczo-geologicznych lub przy nieprawidłowych warunkach pracy, ulegają przyspieszonemu zużyciu. Wpływa to na prędkość i koszty drążenia tych wyrobisk. W artykule przedstawiono opracowane w Katedrze MGPiT AGH Kraków nowe i innowacyjne rozwiązanie głowicy urabiającej, z narzędziami dyskowymi niesymetrycznymi o złożonej trajektorii, jako alternatywę dla standardowych organów frezujących. Opisano zalety zastosowanej metody urabiania z wykorzystaniem tzw. tylnego podcinania oraz zasadę budowy i pracy zaproponowanego rozwiązania przedmiotowej głowicy. Dla opracowania konstrukcji prototypowego egzemplarza tej głowicy koniecznym było określenie, na podstawie badań laboratoryjnych, założeń i wytycznych. Przedstawiono konstrukcję opracowanego specjalnego stanowiska laboratoryjnego do badania narzędzi dyskowych o złożonej trajektorii, założoną metodykę badawczą, przebieg badań oraz uzyskane wyniki. Analiza tych wyników umożliwiła określenie wyżej wymienionych założeń i wytycznych dla konstrukcji głowicy prototypowej. Na ich podstawie opracowano, we współpracy z Zakładami REMAG S.A. w Katowicach, projekt techniczny nowego rozwiązania głowicy, dostosowanej do zabudowy na ramieniu średniego kombajnu chodnikowego KR 150. Wykonany egzemplarz głowicy został poddany próbom na stanowisku badawczym na poligonie Zakładów REMAG i uzyskał pozytywne wyniki badań wstępnych.
Źródło:
Archives of Mining Sciences; 2013, 58, 4; 985-1006
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An evaluation of some morphological traits in doubled haploid lines and their F1 hybrids of head cabbage Kamienna Glowa in the vegetative phase
Autorzy:
Kaminski, P
Powiązania:
https://bibliotekanauki.pl/articles/2042023.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
vegetative phase
cabbage
F1 hybrid
doubled haploid
heterosis
Brassica oleracea var.capitata
Kamienna Glowa cultivar
head cabbage
Źródło:
Journal of Applied Genetics; 2000, 41, 4; 247-252
1234-1983
Pojawia się w:
Journal of Applied Genetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 46

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