Interpopulation variation in germination responses of Scotch thistle, Onopordum acanthium L., to various concentrations of GA3, KNO3, and NaHCO3

2000 ◽  
Vol 78 (9) ◽  
pp. 1156-1163
Author(s):  
Mirwais M Qaderi ◽  
Paul B Cavers
Keyword(s):  
Room Temperature ◽  
Germination Percentage ◽  
The Other ◽  
Germination Inhibitors ◽  
Low Concentration ◽  
Local Populations ◽  
Onopordum Acanthium ◽  
Interpopulation Variation ◽  
Two Populations

The effects of GA3, KNO3, and NaHCO3 on germination percentages and rates were determined for cypselas (seeds) of four local populations of Scotch thistle, Onopordum acanthium L., collected during a 2-year period. Three (1996, stored cypselas) and four (1997, fresh cypselas) concentrations (0.025, 0.05, and 0.1% for both years, plus 0.0125% for 1997) of the three compounds were used. Both freshly collected cypselas and those stored for 67 days at room temperature exhibited a range of germination responses from readily germinable to strongly dormant. GA3, even at a very low concentration, caused most viable cypselas to germinate, but 5-6% of viable cypselas in two populations did not respond to any GA3 treatment. In general, dry-stored cypselas germinated faster than fresh ones. Populations with more germinability (= proportion of cypselas capable of germinating) responded faster to GA3 than those with less germinability. KNO3 usually increased germination percentages but reduced the rate of germination. When treated with KNO3, stored cypselas from the two populations with less germinability germinated more slowly than those of the other two. In general, germination percentage decreased with an increase in NaHCO3 concentration. Overall, stored cypselas that were treated with NaHCO3 germinated more slowly than those in the control. The large differences among four local populations in response to these chemicals suggest that the effects of germination stimulators and other chemicals should be observed on several populations per species.Key words: cypsela, germination promoters, germination inhibitors, local populations, Onopordum acanthium, Scotch thistle.

Effects of dry heat on the germinability and viability of Scotch thistle (Onopordum acanthium) cypselas: interpopulation and interposition variation

2003 ◽  
Vol 81 (7) ◽  
pp. 684-697 ◽  
Author(s):  
Mirwais M Qaderi ◽  
Paul B Cavers
Keyword(s):  
Room Temperature ◽  
Germination Rate ◽  
Surface Cracks ◽  
Fire Event ◽  
Direct Heating ◽  
Dry Heat ◽  
Local Populations ◽  
Onopordum Acanthium

Cypselas (fruits) of four local populations of Scotch thistle, Onopordum acanthium L., were stored for 3 months, heated gradually from room temperature to 50, 75, or 100°C and then gradually cooled to determine effects on germination. Populations responded similarly to this treatment. The lowest germination percentages and slowest rates followed the 100°C treatment, while the fastest germination rates followed 75°C. In a direct-heating experiment, cypselas (from central and peripheral positions in the capitulum) of one population were stored for 41/2 months and then exposed directly to 50, 75, or 100°C for 0.5, 1, or 2 min. This treatment at 75 and 100°C increased germination percentages, with higher percentages for the central cypselas. The 2 min treatment at 100°C yielded the highest percentage and fastest germination rate. Central cypselas were heavier but were similar to peripheral ones in imbibition and in the ratio between cypsela coat and embryo weights. In subsidiary experiments, wax-removed cypselas had smoother surfaces, heated cypselas had visible surface cracks, and germinated cypselas had thinner pericarps. Increases in the percentage and rate of germination in response to dry heat suggest that seedlings of O. acanthium may emerge sooner and in greater numbers following a fire event on disturbed or agricultural lands.Key words: cypsela, dry heat, germination, Onopordum acanthium, Scotch thistle, viability.

Electron microscope studies of the plastic deformation of ternary alloys based on GaAs

1990 ◽  
Vol 48 (4) ◽  
pp. 1120-1120
Author(s):  
R. Haswell ◽  
U. Bangert ◽  
P. Charsley
Keyword(s):  
Plastic Deformation ◽  
Electron Microscope ◽  
Room Temperature ◽  
Stacking Faults ◽  
The Other ◽  
Ternary Alloys ◽  
Dislocation Mobility ◽  
Semiconducting Materials ◽  
Micro Indentation

A knowledge of the behaviour of dislocations in semiconducting materials is essential to the understanding of devices which use them . This work is concerned with dislocations in alloys related to the semiconductor GaAs . Previous work on GaAs has shown that microtwinning occurs on one of the <110> rosette arms after indentation in preference to the other . We have shown that the effect of replacing some of the Ga atoms by Al results in microtwinning in both of the rosette arms.In the work to be reported dislocations in specimens of different compositions of Gax Al(1-x) As and Gax In(1-x) As have been studied by using micro indentation on a (001) face at room temperature . A range of electron microscope techniques have been used to investigate the type of dislocations and stacking faults/microtwins in the rosette arms , which are parallel to the [110] and [10] , as a function of composition for both alloys . Under certain conditions microtwinning occurs in both directions . This will be discussed in terms of the dislocation mobility.

Assessment of micro and macro nutrients in poultry feeds available in Dhaka city, Bangladesh.

2017 ◽  
Vol 1 ◽  
pp. 264
Author(s):  
Md Didarul Islam ◽  
Ashiqur Rahaman ◽  
Fahmida Jannat
Keyword(s):  
Heavy Metals ◽  
Adverse Effect ◽  
The Other ◽  
Nutrient Level ◽  
Dhaka City ◽  
Toxic Heavy Metals ◽  
High Concentration ◽  
Low Concentration ◽  
Feed Formulation ◽  
Macro Nutrients

This study was based on to determine the concentration of macro and micro nutrients as well as toxic and nontoxic heavy metals present in the chicken feed available in Dhaka city of Bangladesh. All macro nutrients, if present in the feed at high concentration have some adverse effect, at the same time if this nutrient present in the feed at low concentration this have some adverse effect too. So that this nutrient level should be maintained at a marginal level. On the other side toxic heavy metals if present in the feed at very low concentration those can contaminate the total environment of the ecosystem. In this study six brand samples (starter, grower, finisher and layer) which was collected from different renowned chicken feed formulation industry in Bangladesh. Those samples were prepared for analysis by wet ashing and then metals were determined by Atomic Absorption Spectroscopy. It was found that 27.7 to 68.4, 57.3 to 121.9, 0.21 to 4.1, 0.32 to 2.1, 0.11 to 1.58, 0.28 to 2.11 and 0.28 to 1.78 for zinc, iron, copper, mercury, cadmium, nickel and cobalt respectively. It was found that essential macro and micro nutrients were present in the feed in low concentration on the other side mercury was present in high concentration in the feed samples.

HAYNES STELLITE ALLOY No. 98M2

Alloy Digest ◽  
1960 ◽  
Vol 9 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Physical Properties ◽  
Room Temperature ◽  
Base Alloy ◽  
Heat Treating ◽  
The Other ◽  
Stellite Alloy ◽  
Cobalt Base Alloy ◽  
Cobalt Base

Abstract HAYNES STELLITE 98M2 Alloy is a cobalt-base alloy having higher compressive strength and higher hardness than all the other cobalt-base alloys at room temperature and in the red heat range. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness. It also includes information on heat treating, machining, and joining. Filing Code: Co-22. Producer or source: Haynes Stellite Company.

The Reactivity of Different Active Forms of Sodium Carbonate with Respect to Sulfur Dioxide

1992 ◽  
Vol 57 (11) ◽  
pp. 2302-2308
Author(s):  
Karel Mocek ◽  
Erich Lippert ◽  
Emerich Erdös
Keyword(s):  
Thermal Decomposition ◽  
Liquid Phase ◽  
Sulfur Dioxide ◽  
Specific Surface ◽  
Surface Area ◽  
Sodium Carbonate ◽  
Room Temperature ◽  
Active Form ◽  
The Other ◽  
Kinetics Of

The kinetics of the reaction of solid sodium carbonate with sulfur dioxide depends on the microstructure of the solid, which in turn is affected by the way and conditions of its preparation. The active form, analogous to that obtained by thermal decomposition of NaHCO3, emerges from the dehydration of Na2CO3 . 10 H2O in a vacuum or its weathering in air at room temperature. The two active forms are porous and have approximately the same specific surface area. Partial hydration of the active Na2CO3 in air at room temperature followed by thermal dehydration does not bring about a significant decrease in reactivity. On the other hand, if the preparation of anhydrous Na2CO3 involves, partly or completely, the liquid phase, the reactivity of the product is substantially lower.

Fe-Ti Bimetal Oxide Adsorbent for Removing Low Concentration H2S at Room Temperature

2021 ◽  
pp. 1-21
Author(s):  
Zhuangzhuang Guo ◽  
Zhihong Zhang ◽  
Xiaoyan Cao ◽  
Dongfang Feng
Keyword(s):  
Room Temperature ◽  
Low Concentration

scholarly journals Synthesis of spiro[dihydropyridine-oxindoles] via three-component reaction of arylamine, isatin and cyclopentane-1,3-dione

2013 ◽  
Vol 9 ◽  
pp. 8-14 ◽  
Author(s):  
Yan Sun ◽  
Jing Sun ◽  
Chao-Guo Yan
Keyword(s):  
Acetic Acid ◽  
Reaction Mechanism ◽  
Room Temperature ◽  
The Other ◽  
Other Hand ◽  
Three Component Reaction ◽  
High Yields

A fast and convenient protocol for the synthesis of novel spiro[dihydropyridine-oxindole] derivatives in satisfactory yields was developed by the three-component reactions of arylamine, isatin and cyclopentane-1,3-dione in acetic acid at room temperature. On the other hand the condensation of isatin with two equivalents of cyclopentane-1,3-dione gave 3,3-bis(2-hydroxy-5-oxo-cyclopent-1-enyl)oxindole in high yields. The reaction mechanism and substrate scope of this novel reaction is briefly discussed.

On the Chemistry of Tetrabenzyl Thiuram Disulfide and Tetramethyl Thiuram Disulfide with Bis (Triethoxysilylpropyl) Tetrasulfide in Silica Compounds

2003 ◽  
Vol 76 (4) ◽  
pp. 876-891 ◽  
Author(s):  
R. N. Datta ◽  
A. G. Talma ◽  
S. Datta ◽  
P. G. J. Nieuwenhuis ◽  
W. J. Nijenhuis ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Succinic Anhydride ◽  
Dynamic Properties ◽  
The Other ◽  
Resonance Spectroscopy ◽  
Reaction Products ◽  
Negative Effect ◽  
Higher Temperature ◽  
Analytical Tools

Abstract The use of thiurams such as Tetramethyl thiuram disulfide (TMTD) or Tetrabenzyl thiuram disulfide (TBzTD) has been explored to achieve higher cure efficiency. The studies suggest that a clear difference exists between the effect of TMTD versus TBzTD. TMTD reacts with Bis (triethoxysilylpropyl) tetrasulfide (TESPT) and this reaction can take place even at room temperature. On the other hand, the reaction of TBzTD with TESPT is slow and takes place only at higher temperature. High Performance Liquid Chromatography (HPLC) with mass (MS) detection, Nuclear Magnetic Resonance Spectroscopy (NMR) and other analytical tools have been used to understand the differences between the reaction of TMTD and TESPT versus TBzTD and TESPT. The reaction products originating from these reactions are also identified. These studies indicate that unlike TMTD, TBzTD improves the cure efficiency allowing faster cure without significant effect on processing characteristics as well as dynamic properties. The loading of TESPT is reduced in a typical Green tire compound and the negative effect on viscosity is repaired by addition of anhydrides, such as succinic anhydride, maleic anhydride, etc.

scholarly journals Recent Observations on the Mechanical Properties of Polymer Networks

1971 ◽  
Vol 44 (5) ◽  
pp. 1256-1272 ◽  
Author(s):  
P. Thirion ◽  
R. Chasset
Keyword(s):  
Crosslink Density ◽  
Room Temperature ◽  
Dynamic Properties ◽  
Polymer Networks ◽  
The Other ◽  
Dilution Ratio ◽  
Chain Entanglement ◽  
Influence Of Temperature ◽  
Terminal Zone ◽  
Crosslinking Agents

Abstract The influence of temperature, elongation, swelling or dilution ratio, crosslink density, nature of the polymers, and crosslinking agents on the dynamic properties, creep and relaxation of polymer networks is surveyed in the terminal region of the spectrum. Whereas the deformation does not change the relaxation kinetics in large ranges of extension, the crosslink density acts as a reduced variable apparently accelerating uniformly the viscoelastic processes beyond the glass transition. The other possible reductions ‘time-temperature’ and ‘time—swelling’ do not necessarily seem related to the variations of free volume. From the viewpoint of the explanation of the relaxation mechanisms in the terminal zone, the fact that the equilibrium of loosely crosslinked elastomers would only virtually be reached after several years at room temperature seem in better agreement with chain entanglement effects, either trapped or not by the permanent network, than with the dissociation of secondary linkages.

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