scholarly journals Root age influences failure location in grass species during mechanical testing

2021 ◽  
Author(s):  
David Boldrin ◽  
Anthony Glyn Bengough ◽  
Zijian Lin ◽  
Kenneth Wilhelmus Loades
Keyword(s):  
Festuca Arundinacea ◽  
Lolium Multiflorum ◽  
Testing Machine ◽  
Test Validity ◽  
Tensile Tests ◽  
Grass Species ◽  
Group 2 ◽  
Failure Location ◽  
Fibrous Roots ◽  
Root Axis

Abstract Aims Root tensile tests are often rejected if failure location is outside the middle section of samples. This study aims to identify where and why failure occurs along a root axis, and hence to revisit current approaches to test-validity. Methods Roots from Festuca arundinacea; Lolium multiflorum; Lolium perenne were sampled from field-grown plants. Roots were tensile tested using a universal testing machine. Root samples were randomly allocated into two groups for testing. Group 1 roots were orientated with the older tissue closest to the top clamp, group 2 roots were orientated oppositely. Tensile strength, Young’s modulus and failure location were recorded for each sample. Results Lolium multiflorum roots were thinner and stronger than roots of Festuca arundinacea. Failure location in tensile tests depended significantly on tissue age with 75% of samples failing in the younger third of root tissue regardless of the root orientation in the testing frame. Only 7% of roots failed in the middle third of the sample. Conclusions Fibrous roots tested in tension were observed to consistently fail in the younger tissue along the root axis. Exclusion of samples which fail outside the middle region of the root axis needs re-evaluation for a range of species.

scholarly journals Branching of tillers in some grasses

2013 ◽  
Vol 34 (1) ◽  
pp. 53-67
Author(s):  
Leontyna Olszewska ◽  
Maria Wielicka
Keyword(s):  
Cross Section ◽  
Festuca Arundinacea ◽  
Lolium Multiflorum ◽  
Phleum Pratense ◽  
Grass Species ◽  
Holcus Lanatus ◽  
Starting Point ◽  
Formation Conditions ◽  
Arrhenatherum Elatius

In investigations on the grass regeneration biology a special attention was paid to the formation of aerial tillers and branching pseudostolons in <i>Dactylis glomerata</i> L., <i>Festuca arundinacea</i> Schreb., <i>Festuca pratensis</i> Huds., <i>Festuca rubra</i> L., <i>Phleum pratense</i> L., <i>Lolium multiflorum</i> Lam., <i>Lolium perenne</i> L., <i>Phalaris arundinacea</i> L., <i>Arrhenatherum elatius</i> (L.) P. B., <i>Holcus lanatus</i> L., <i>Agropyron repens</i> (L.) P. B., <i>Avenastrum pubescens</i> (Huds) Opiz and <i>Agrostis alba</i> L. Aerial tillers, vegetative short ones and with partly elongated internodes as well as generative tillers formed in tufted and rhizomatous grasses. Parental raised tillers, on which aerial tillers developed, had the anatomical structure specific for grass stems. In tufted grasses, moreover, parental branching pseudostolons developed; in their cross section the arrangement of tissues specific for stolons was observed. They constituted the starting point for agglomerations of new plants rooting in soil, contrary to raised tillers. In some grass species, beside pendant roots, shorter roots grew at the base of aerial tillers; they surrounded with a ring the parent shoot in the node, thus reinforcing the connection of aerial tillers with the stem. An attention was paid to the favourable role of branching pseudostolons in the sward thickness formation. Conditions of the arrangement of tissues in the stem cross section, owing to which the rhizomatous form is developed, are discussed. The fertilization with compost or the covering with sand results in the formation of tillers resembling pseudorhizomes.

Herbage production and tiller density in five related grasses, their hybrids and mixtures

1996 ◽  
Vol 127 (1) ◽  
pp. 57-65 ◽  
Author(s):  
D. Wilman ◽  
Y. Gao
Keyword(s):  
Perennial Ryegrass ◽  
Tall Fescue ◽  
Festuca Arundinacea ◽  
Lolium Multiflorum ◽  
Italian Ryegrass ◽  
Grass Species ◽  
Meadow Fescue ◽  
The Mean ◽  
Tiller Density ◽  
Better Than

SUMMARYFour grass species, three hybrids and three mixtures were grown in field swards near Aberystwyth. All swards were amply supplied with nutrients and were cut at 5-week intervals during the year of sowing (1989) and during the following 4 years. The order of the grasses in rate of establishment was: Westerwolds ryegrass > Italian ryegrass (Lolium multiflorum) > Italian ryegrass × perennial ryegrass, Italian ryegrass × meadow fescue, perennial ryegrass (Lolium perenne) > perennial ryegrass × meadow fescue, meadow fescue (Festuca pratensis) > tall fescue (Festuca arundinacea). During the sowing year as a whole, Italian ryegrass was the highest yielding grass, followed by Westerwolds ryegrass. During the remaining period (1990–93), as a whole, the highest yields were obtained from perennial ryegrass sown alone or in a mixture with tall fescue. Tall fescue sown alone was one of the lowest yielding grasses in the year of sowing, but developed to be the highest yielding in 1992 and 1993. Westerwolds ryegrass persisted least well, although some plants did survive until 1992. Italian ryegrass persisted better than Westerwolds and Italian ryegrass × meadow fescue persisted better than Italian ryegrass. Hybrid ryegrass and perennial ryegrass × meadow fescue persisted satisfactorily but with fewer tillers/m2 than perennial ryegrass or tall fescue. The yield of tall fescue in March was as high as that of Italian ryegrass in 1990 and 1991 and higher than that of any of the other grasses in 1992 and 1993; the tiller density of tall fescue was particularly high in March. The yield of mixtures (Italian ryegrass with perennial ryegrass, Italian ryegrass with tall fescue and perennial ryegrass with tall fescue) was, on average, 2·5% more than the mean of the component species when sown alone. When grown with ryegrass, tall fescue was not prominent initially but its proportion in the sward gradually increased.

CHLORIDE UPTAKE BY VARIOUS TURFGRASS SPECIES AND CULTIVARS

1971 ◽  
Vol 51 (6) ◽  
pp. 485-490 ◽  
Author(s):  
W. E. CORDUKES ◽  
E. V. PARUPS
Keyword(s):  
Festuca Arundinacea ◽  
Poa Pratensis ◽  
Lolium Multiflorum ◽  
Chloride Content ◽  
Kentucky Bluegrass ◽  
Phleum Pratense ◽  
Italian Ryegrass ◽  
Grass Species ◽  
Red Fescue ◽  
Chloride Uptake

Twelve cultivars representing eight grass species were each grown in a sand/vermiculite medium in the greenhouse, fed six solutions varying in chloride content for 140 days, and cut at lawn height. Six harvests were obtained and analyzed for chloride uptake. Visual ratings and yields indicated that the grasses tolerate relatively high chloride levels for a considerable time. Chloride uptake increased with time and increasing chloride content of the solutions. Uptake was less from alkaline than from acid solutions. Highland bentgrass (Agrostis tenuis Sibth.), Italian ryegrass (Lolium multiflorum Lam.) and timothy (Phleum pratense L.) were the least tolerant, while Norlea perennial ryegrass (Lolium perenne L.) and Kentucky 31 tall fescue (Festuca arundinacea Schreb.) were the most tolerant to chlorides. Kentucky bluegrass (Poa pratensis L.) and creeping red fescue (Festuca rubra L.) were intermediate in this respect.

scholarly journals Determination of indigestible neutral detergent fibre contents of grasses and its prediction from chemical composition

2008 ◽  
Vol 53 (No. 3) ◽  
pp. 128-135 ◽  
Author(s):  
F. Jančík ◽  
P. Homolka ◽  
B. Čermák ◽  
F. Lád
Keyword(s):  
Festuca Arundinacea ◽  
Lolium Multiflorum ◽  
Phleum Pratense ◽  
Grass Species ◽  
Neutral Detergent Fibre ◽  
Rumen Degradation ◽  
Lactating Cows ◽  
Acid Detergent Lignin ◽  
Acid Detergent Fibre ◽  
Highly Correlated

Five grass species (<I>Dactylis glomerata</I> L., <I>Phleum pratense</I> L.,<I> Lolium perenne</I> L., <I>Festuca arundinacea</I> L.) and the hybrid Felina (<I>Lolium multiflorum</I> L. × <I> Festuca arundinacea</I> L.), commonly used in roughages for ruminants, were harvested at different maturities of primary growth (<I>n</I> = 60) and evaluated for contents of dry matter (DM), crude protein (CP), ash, crude fat, neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL), indigestible neutral detergent fibre (INDF) and digestible neutral detergent fibre (DNDF). INDF and DNDF contents were determined by <I>in sacco</I> rumen degradation of grasses for 12 days in non-lactating cows. ADL content was found to be highly correlated (<I>P</I> < 0.05) with DNDF (<I>r</I> = –0.87) and presented a reliable (<I>R</I><sup>2</sup> = 0.78; residual mean square error of 17.65 g/kg DM; <I>P</I> < 0.0001) parameter to predict INDF contents. Over a six-week period of maturation INDF contents increased (<I>P</I> < 0.0001) in all studied grasses. It was confirmed by this study that the INDF contents of grasses, which markedly increased during maturation, could be effectively predicted from ADL contents.

Formation of botanical composition of clover cereal and alfalfa cereal crops agrophytocenoses depending on sowing method

2020 ◽  
pp. 160-168
Author(s):  
I. Senyk
Keyword(s):  
Festuca Arundinacea ◽  
Global Climate ◽  
Phleum Pratense ◽  
Grass Species ◽  
Cereal Crops ◽  
Forest Steppe ◽  
Botanical Composition ◽  
Cross Sectional ◽  
Row Crops ◽  
Adverse Weather

Botanical composition of grasses is one of the most important indicators the biological value and quality of the obtained hay and pasture forage, the longevity of hayfi elds and pastures depend on. The issue of changing the botanical composition of agrophytocenoses is especially important in the context of global climate change, which in recent decades is also manifested in the territory of Ukraine, as it is possible to establish the most adapted species of legumes and cereals to adverse weather conditions and to identify eff ective technological methods of managing these processes for maximum conservation economically valuable species in the herbage. The purpose of the research is to establish the infl uence of diff erent ways of sowing of clover and alfalfa cereal crops agrophytocenoses on the formation of their botanical composition. Field studies have established diff erent eff ects of conventional in-line, cross-section and cross-sectional methods of sowing on the formation of botanical composition of grass mixtures of clover meadow (Trifolium pratense) varieties Sparta and Pavlyna with timothy meadow (Phleum pratense) and fenugreek multifl oral (Lolium multifl orum) and of agrophytocenoses of alfalfa of Sinyukha and Seraphima sowing varieties with reed fire (Festuca arundinacea Schreb) and middle wheatgrass (Elytrigia intermedia). For the average of four years of life of clover and alfalfa cereal crops agrophytocenoses, the highest proportion of legume component was observed with split-cross sowing – 51.6 % for Sparta, 53.1 % for Pavlyna, 60.3 % for Seraphima and 61.6 % for the Sinyukha variety. In the fourth year of life (the third year of use) of sowed leguminous-cereals agrophytocenoses, the preservation of the legume component was 14.6–15.5 % in clover-cereals grass mixtures with the Sparta variety and 16.0–16.8 % with the Pavlyna variety. In alfalfa grasslands, these indicators were 54.0–55.1 % with Seraphim and 55.0–56.2 % with Sinyukha. Among the studied varieties of clover meadow and alfalfa sowing proved better in the conditions of the Forest Steppe of western Pavlyna and Sinyukha. Cross-sectional and divided cross-sectional sowing of legumes and cereals mixtures proved to be better compared to conventional row crops in terms of conservation of economically valuable grass species. Key words: agrophytocenosis, botanical composition, clover meadow, alfalfa sowing, sowing methods.

scholarly journals Resistance to Fracture of Dental Roots Obturated with Different Materials

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Berkan Celikten ◽  
Ceren Feriha Uzuntas ◽  
Kamran Gulsahi
Keyword(s):  
Fracture Resistance ◽  
Testing Machine ◽  
Negative Control Group ◽  
Positive Control ◽  
Negative Control ◽  
Positive Control Group ◽  
Control Group ◽  
Root Canal Filling ◽  
Filling Materials ◽  
Group 2

The aim of this study was to compare the vertical fracture resistance of roots obturated with different root canal filling materials and sealers. Crowns of 55 extracted mandibular premolar teeth were removed to provide root lengths of 13 mm. Five roots were saved as negative control group (canals unprepared and unfilled). Fifty root canals were instrumented and then five roots were saved as positive control group (canals prepared but unfilled). The remaining 45 roots were randomly divided into three experimental groups (n=15root/group) and obturated with the following procedures: in group 1, glass ionomer-based sealer and cone (ActiV GP obturation system); in group 2, bioceramic sealer and cone (EndoSequence BC obturation system); and in group 3, roots were filled with bioceramic sealer and cone (Smartpaste bio obturation system). All specimens were tested in a universal testing machine for measuring fracture resistance. For each root, the force at the time of fracture was recorded in Newtons. The statistical analysis was performed by using Kruskal-Wallis and post hoc test. There were no significant differences between the three experimental groups. The fracture values of three experimental and negative control groups were significantly higher than the positive control group. Within the limitations of this study, all materials increased the fracture resistance of instrumented roots.

scholarly journals Fracture Load of Metal, Zirconia and Polyetheretherketone Posterior CAD-CAM Milled Fixed Partial Denture Frameworks

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 959
Author(s):  
Verónica Rodríguez ◽  
Celia Tobar ◽  
Carlos López-Suárez ◽  
Jesús Peláez ◽  
María J. Suárez
Keyword(s):  
Computer Aided Design ◽  
Testing Machine ◽  
Fracture Load ◽  
Fracture Pattern ◽  
Bending Test ◽  
Weibull Statistics ◽  
Promising Alternative ◽  
Computer Aided ◽  
Cad Cam ◽  
Group 2

The aim of this study was to investigate the load to fracture and fracture pattern of prosthetic frameworks for tooth-supported fixed partial dentures (FPDs) fabricated with different subtractive computer-aided design and computer-aided manufacturing (CAD-CAM) materials. Materials and Methods: Thirty standardized specimens with two abutments were fabricated to receive three-unit posterior FDP frameworks with an intermediate pontic. Specimens were randomly divided into three groups (n = 10 each) according to the material: group 1 (MM)—milled metal; group 2 (L)—zirconia; and group 3 (P)—Polyetheretherketone (PEEK). The specimens were thermo-cycled and subjected to a three-point bending test until fracture using a universal testing machine (cross-head speed: 1 mm/min). Axial compressive loads were applied at the central fossa of the pontics. Data analysis was made using one-way analysis of variance, Tamhane post hoc test, and Weibull statistics (α = 0.05). Results: Significant differences were observed among the groups for the fracture load (p < 0.0001). MM frameworks showed the highest fracture load values. The PEEK group registered higher fracture load values than zirconia samples. The Weibull statistics corroborated these results. The fracture pattern was different among the groups. Conclusions: Milled metal provided the highest fracture load values, followed by PEEK, and zirconia. However, all tested groups demonstrated clinically acceptable fracture load values higher than 1000 N. PEEK might be considered a promising alternative for posterior FPDs.

scholarly journals The Performance of CR180IF and DP600 Laser Welded Steel Sheets under Different Strain Rates

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1553
Author(s):  
Mária Mihaliková ◽  
Kristína Zgodavová ◽  
Peter Bober ◽  
Anna Špegárová
Keyword(s):  
Sheet Steel ◽  
Testing Machine ◽  
Dynamic Test ◽  
Tensile Tests ◽  
Joint Surface ◽  
Strain Rates ◽  
Interstitial Free ◽  
Welded Steel ◽  
Steel Sheets ◽  
Static Tensile

The presented research background is a car body manufacturer’s request to test the car body’s components welded from dissimilar steel sheets. In view of the vehicle crew’s protection, it is necessary to study the static and dynamic behavior of welded steels. Therefore, the influence of laser welding on the mechanical and dynamical properties, microstructure, microhardness, and welded joint surface roughness of interstitial free CR180IF and dual-phase DP600 steels were investigated. Static tensile tests were carried out by using testing machine Zwick 1387, and dynamic test used rotary hammer machine RSO. Sheet steel was tested at different strain rates ranging from 10−3 to 103 s−1. The laser welds’ microstructure and microhardness were evaluated in the base metal, heat-affected zone, and fusion zone. The comprehensive analysis also included chemical analysis, fracture surface analysis, and roughness measurement. The research results showed that the strain rate had an influence on the mechanical properties of base materials and welded joints. The dynamic loading increases the yield stress more than the ultimate tensile strength for the monitored steels, while the most significant increase was recorded for the welded material.

Using Embossing to Create a Fiber Reinforced Honeycomb Composite

2005 ◽  
Vol 127 (2) ◽  
pp. 257-262 ◽  
Author(s):  
William Jordan
Keyword(s):  
Tensile Strength ◽  
Composite Material ◽  
Carbon Fibers ◽  
Flexural Modulus ◽  
Testing Machine ◽  
Charpy Impact ◽  
Tensile Tests ◽  
Hydraulic Testing ◽  
Charpy Impact Toughness ◽  
Bend Tests

This research project used hot embossing to create a strong and tough polymeric based composite structure. A honeycomb type structure was created by pressing small grooves into thin polycarbonate sheets. A trapezoidal die was used to create hexagonal shaped channels in the polymeric sheet. A number of these sheets were then bonded together to form a composite material. Carbon fibers were embedded into the channels in some of the laminates. The embossing process was carried out at an elevated temperature in an environmental chamber attached to an MTS servo hydraulic testing machine. The grooved structure had a 31% to 45% decrease in the apparent density compared to the ungrooved specimens. Bend tests, tensile tests, and Charpy impact tests were performed on laminates made from this material. The specific values of tensile strength, flexural modulus, and Charpy impact toughness were increased. A small percentage of fibers significantly increased both the stiffness and strength of the laminate.

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