Wyniki wyszukiwania

1

Zastosowanie metody statycznego sondowania do oceny stanu zageszczenia budowli ziemnych

100%

Tschuschke W.

Roczniki Akademii Rolniczej w Poznaniu. Melioracje i Inżynieria Środowiska

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1993

|

tom 12

135-142

2

Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik

Określenie zależności współczynnika tarcia wewnętrznego od modułu younga ziarna kukurydzy o różnej wilgotności

86%

Frontczak J., Metzger T.

Zeszyty Problemowe Postępów Nauk Rolniczych

|

1987

|

tom 320

3

Metoda pomiaru sily tarcia wewnetrznego biologicznych materialow sypkich

86%

Fraczek J.

Zeszyty Problemowe Postępów Nauk Rolniczych

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1995

|

tom 423

93-101

W pracy przedstawiono nową metodę pomiaru siły tarcia wewnętrznego, umożliwiającą przeprowadzenie badań wpływu wielu czynników decydujących o przebiegu procesu tarcia wewnętrznego.

4

Precyzja oceny stopnia zageszczenia i kata tarcia wewnetrznego gruntu nasypowego metoda CPT

86%

Tschuschke W.

Roczniki Akademii Rolniczej w Poznaniu. Melioracje i Inżynieria Środowiska

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1993

|

tom 12

127-134

5

Badania niektórych wlaściwości powierzchni nasion na przykładzie modrzewia europejskiego

72%

Czernik Z.

Sylwan

|

1997

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tom 141

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nr 06

71-79

6

Badania nad określeniem współczynników tarcia wewnętrznego ziarna kukurydzy

72%

Metzger T., Mosz J.

Roczniki Nauk Rolniczych. Seria C:Technika Rolnicza

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1986

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tom 76

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nr 4

7

Zastosowanie pylow z elektrofiltrow cementowni do poprawy statecznosci skarp na skladowiskach odpadow komunalnych

58%

Pilch E., Pilch A.

Ochrona Powietrza i Problemy Odpadów

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1999

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tom 33

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nr 3

118-120

8

Kukurydza. Czesc 3. Wlasciwosci fizyczne masy zbozowej

58%

Gasiorowski H.

Przegląd Zbożowo-Młynarski

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2007

|

tom 51

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nr 05

30-32

9

Doskonalenie procedury wyznaczania kata tarcia wewnetrznego ziarna zboz metoda trojosiowego sciskania

58%

Horabik J., Lukaszuk J.

Acta Agrophysica

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2002

|

tom 78

63-74

10

Metody oznaczania fizycznych właściwości surowców i mieszanek paszowych

58%

Grochowicz J., Laskowski J.

Zeszyty Problemowe Postępów Nauk Rolniczych

|

1987

|

tom 321

11

Technologiczne aspekty procesu dozowania sypkich materialow rolno-spozywczych

51%

Opielak M., Komsta H.

Pasze Przemysłowe

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1997

|

tom 06

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nr 10

12-14

12

Wplyw ksztaltu nasion i upakowania zloza na kat tarcia wewnetrznego

44%

Molenda M., Stasiak M.

Acta Agrophysica

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2003

|

tom 82

131-137

13

Wplyw struktury zloza nasion na stan naprezenia

44%

Molenda M.

Acta Agrophysica

|

1998

|

tom 12

129

The spatial arrangement of individual grains forming a bed of granular solids influences the mechanical behaviour of granular material. Several researchers reported reduction of the coordination number and an increase of the void fraction in the region near the wall of containers holding randomly packed beds of uniform spheres. The method of bin filling influences the pressure distribution on the wall as well as the flow pattern which develops at the onset of discharge. Anisotropic behaviour of grain medium was considered to be the reason for damage to silos built in compliance with current codes of practice. It was found that the filling method influences the magnitude of measured values of the stress ratio. The purpose of this study was to examine the influence of particle properties and bedding structure on transmission of stresses in the layer of seeds, A model bin 0.61 m in diameter and 0.62 m high was constructed. Its bottom was divided into five concentric rings. The apparatus allowed for the determination of vertical load on each of the floor rings, vertical wall load and horizontal load exerted by grain on the bin wall. Four methods of bin filling and two types of wall surface (rough and smooth) were tested. The seeds of five species of plants were used as bulk solids filling the bin. The filing method, and individual seed size and shape of the five test materials significantly influenced the radial distribution of vertical pressure on the silo bottom. From a practical point of view, the advantages of circumferential filling as compared to central filling are: lower pressure ratio, maximum of vertical pressure at the bottom centre and lower tangential stress in vertical direction. The characteristics of vertical pressure as the function of the radius was observed to be smooth for the ratio of bin radius to particle dimension higher than one hundred. The change in moisture content of wheat resulted in the change ofradial distribution of vertical pressure. The wall of the bin was loaded gravitationally and allowed to move down. The characteristics of shear stress as the function of the radius was found to be dependent on the seed size. The major part of shear stress change took place in the boundary layer along the wall, which thickness was less than ten seed equivalent diameters. The proposed method measures vertical normal pressure averaged over the cross sectional area and the horizontal normal pressure averaged over the perimeter. Simultaneously, it measures the coefficient of wall friction, thus the pressure ratio is determined in a manner consistent with the Janssen formula. The pressure ratio value was found affected by material type, filling method and load history. Analysis of radial variation of vertical pressure can be useful in the verification of assumptions concerning the location of regions of fully developed yield conditions inside the Janssen's differential slice which are frequently considered in the theoretical prediction of the stress ratio.

14

Wlasciwosci fizyczne sypkich surowcow spozywczych. Zarys katalogu

44%

Horabik J., Molenda M.

Acta Agrophysica

|

2002

|

tom 74

1-90

15

Tarcie ziarna pszenicy

44%

Molenda M., Horabik J., Grochowicz M., Szot B.

Acta Agrophysica

|

1995

|

tom 04

88

All phases of particulate material industry, namely, storage, handling and processing are operations that require precise knowledge of the behaviour of the material to achieve the desired control.External and internal friction of particulate material greatly influence its mechanical behaviour.A lot of work was done on agricultural grain since 1960`s. This work summarizes the methods and results of these studies and presents the results of the autor1s own experiments. It was divided into two parts: 1.Internal friction and 2. External friction. Own studies for the first section were performed using direct shearing box and triaxial compression chamber which dimensions were anlarged to regard the size of cereal grain. Density, moisture content of grain and its spatial orientation were taken into account as the most important factors forinternal friction. All of them were found to influence significantly the angle of internal friction of grain. For the external friction section own method of measurements was applied. Friction coefficient was measured for a part of wheat grains sliding against a steel or glass platesandwiched between them. The true contact area of grain with a flat glass surface was measured with microscope photography in reflected light. The relations between tangential force and normal force on the one hand and the true contact area versus normal force on the other were obtained and examined. Parameters taken into account were: grain moisture content, type of endosperm, cutin cover, variety, location of cultivation, and roughness of sliding surface and that of grain itself. All these factors were found to influence significantly obtained frictional characteristics. The obtained results pointed out to the fact that both internal and external friction of cereal grain depend on a number of factors which caused unexplained scatter of experimental results, and in a greater part of theoretical works were left out of account.

16

Standaryzacja metod pomiaru wlasciwosci fizyczno-mechanicznych roslinnych materialow ziarnistych

37%

Fraczek J., Kaczorowski J., Slipek Z., Horabik J., Molenda M.

Acta Agrophysica. Rozprawy i Monografie

|

2003

|

nr 92

1-160

Ograniczanie wyników

Zastosowanie metody statycznego sondowania do oceny stanu zageszczenia budowli ziemnych

Określenie zależności współczynnika tarcia wewnętrznego od modułu younga ziarna kukurydzy o różnej wilgotności

Metoda pomiaru sily tarcia wewnetrznego biologicznych materialow sypkich

Precyzja oceny stopnia zageszczenia i kata tarcia wewnetrznego gruntu nasypowego metoda CPT

Badania niektórych wlaściwości powierzchni nasion na przykładzie modrzewia europejskiego

Badania nad określeniem współczynników tarcia wewnętrznego ziarna kukurydzy

Zastosowanie pylow z elektrofiltrow cementowni do poprawy statecznosci skarp na skladowiskach odpadow komunalnych

Kukurydza. Czesc 3. Wlasciwosci fizyczne masy zbozowej

Doskonalenie procedury wyznaczania kata tarcia wewnetrznego ziarna zboz metoda trojosiowego sciskania

Metody oznaczania fizycznych właściwości surowców i mieszanek paszowych

Technologiczne aspekty procesu dozowania sypkich materialow rolno-spozywczych

Wplyw ksztaltu nasion i upakowania zloza na kat tarcia wewnetrznego

Wplyw struktury zloza nasion na stan naprezenia

Wlasciwosci fizyczne sypkich surowcow spozywczych. Zarys katalogu

Tarcie ziarna pszenicy

Standaryzacja metod pomiaru wlasciwosci fizyczno-mechanicznych roslinnych materialow ziarnistych