188,481 research outputs found
Sweet Corn Topping Evaluation
No full textSweet corn “topping” is the removal of plant parts above the ear after pollination has occurred. This practice has been reported to hasten maturity, improve picking ease, reduce bird damage, improve pesticide application to ears, and reduce lodging problems. Disadvantages of topping have included a reduction in earsize, poor kernel fill,sunburn of exposed ears, and additional production costs. The objective was to determine what effect topping would have on ear maturity, yield, and ear quality under Iowa growing conditions.</p
Buckling analysis of aluminium alloy structures accounting for friction stir welding effects
No full textThe joining of aluminium alloy parts using welding techniques can be responsible for changes in the final structures such as geometrical distortions, variation of material properties and residual stresses. These effects can influence the strength of structures and must be taken into account at the design stage. The main objective of the work, described in this paper, is to assess the influence of friction stir welding processes on the load capacity of a stiffened panel subjected to longitudinal compressive loads. A numerical model, based on a finite element approach and simulating the friction stir welding process, is developed in order to evaluate these induced effects on a stiffened panel structure. Afterwards, a compressive load is applied on the structure until the collapse load is reached. The results are compared with those coming from a model not including welding simulation. It is inferred that welding effects (namely, residual stresses and material properties changes) can strongly reduce the collapse load level of the studied structure
Ultra Thin White Topping
No full textPaper consists of subsistence of highway road and improvement in low cost and increasing the strength and vitality of the pavement. Ultra-Thin White Topping may be defined as a concrete cover with closely spaced joints and bonded to an existing bituminous pavement. It consists of a fine layer of high durability, fibre-reinforced concrete laid over a clean, milled surface of distressed bituminous concrete pavement, to achieve full or partial bonding. From the degradation summary it is identified that even after 10 years, the riding quality of Ultra-Thin White Topping is the most admirable and the most desirable one without any mediation. Structural collapse emerges from the action that contrarily affects the traffic volume carrying capacity of the pavement. This structural collapse can be overcome by using Ultra-Thin White Topping pavement over bituminous pavement. Ultra-Thin White Topping achieves very low End User Cost values thus resulting in the maximization of Gross Economic Benefits than that of ordinary bitumen overlay
Multiple Crack Propagation in Friction Stir Welded Aluminium Joints
No full textThis paper is concerned with the simulation of crack propagation in friction stir welded butt joints, in order to assess the influence of process induced
microstructural alterations and residual stresses on the fatigue behaviour of the assembly. The approach employed is based on the coupled use of the finite element method and the dual boundary element method in order to take advantage of the main capabilities of the two methods. The distribution of the process induced residual stresses has been mapped by means of the contour method. Then, the computed residual stresses field has been superimposed, in a dual boundary element environment, to the stress field as a result of a remote fatigue traction load and the crack growth is simulated. A two-parameter crack growth law, based on the evaluation of two thresholds, for the material being analysed, is used for the crack propagation rate assessment. The stress intensity factors are evaluated using the Jintegral technique. Computational results have been compared with experimental data, provided from constant amplitude crack propagation tests on welded samples, showing the subdivision of the overall fatigue life in the two periods of crack initiation and crack propagation
Effects of plant topping on rhizome yield and components of <i>P</i>. <i>cyrtonema</i>.
No full textEffects of plant topping on rhizome yield and components of P. cyrtonema.</p
Chemical topping of burley tobacco
No full textTopping tobacco (Nicotiana tabacum L.) is a procedure that requires the removal of the terminal bud or inflorescence of the plant. Topping tobacco has been a common practice almost since tobacco has been domestically cultivated, due to the desirable effect it has on yield and quality of the tobacco leaf. The objective of this study was to determine if burley tobacco can be chemically topped using common sucker control materials. The burley tobacco variety TN 86 and the non-flowering burley tobacco breeding line BM 16 were used in the research study. Four chemical topping treatments were applied to both burley tobacco lines. These included: KMH; KMH tank mixed with flumetralin (KMH/P+); FST7 tank mixed with flumetralin (FST7/P+); and FST7, followed one week later with a treatment of flumetralin (FST7-P+). These treatments were applied at three different plant growth stages. Chemical treatments were applied at either the 25, 50, or 75 percent button stage for TN 86 and either the 25, 30, or 35 leaf stage of maturity for BM 16. The most effective chemical topping for TN 86 occurred when chemical treatments were applied at the 25 percent button growth stage. Applications at later maturity stages resulted in less effective chemical topping. Compared to the hand topped check, all the chemical topping treatments resulted in reduced yields. Although the most effective topping was achieved at the 25 percent button maturity stage, application of chemicals at this stage resulted in the largest yield reduction. This yield reduction was due to reduced leaf size, which lowered cured leaf weight in the upper portion of the plant. For BM 16, excellent topping was obtained with all of the chemical treatments, regardless of the growth stage at which they were applied. In comparison to the hand topped check, yields of BM 16 were reduced by all chemical treatments when applied at the 25 leaf stage of maturity; however all treatments applied at the 35 leaf stage resulted in increased yields. Although the size of at least the top three leaves of the plant were reduced, regardless of chemical treatment or time of application, yields of BM 16 increased due to the higher number of harvestable leaves
Response of a buried tunnel to surface blast using different numerical techniques
No full textThis paper presents a comparative study on the response of a buried tunnel to surface blast using the arbitrary Lagrangian-Eulerian (ALE) and smooth particle hydrodynamics (SPH) techniques. Since explosive tests with real physical models are extremely risky and expensive, the results of a centrifuge test were used to validate the numerical techniques. The numerical study shows that the ALE predictions were faster and closer to the experimental results than those from the SPH simulations which over predicted the strains. The findings of this research demonstrate the superiority of the ALE modelling techniques for the present study. They also provide a comprehensive understanding of the preferred ALE modelling techniques which can be used to investigate the surface blast response of underground tunnels
The canonical shrinking soliton associated to a Ricci flow
No full textTo every Ricci flow on a manifold over a time interval , we associate a shrinking Ricci soliton on the space-time . We relate properties of the original Ricci flow to properties of the new higher-dimensional Ricci flow equipped with its own time-parameter. This geometric construction was discovered by consideration of the theory of optimal transportation, and in particular the results of the second author Topping (J Reine Angew Math 636:93-122, 2009), and McCann and the second author (Am J Math 132:711-730, 2010); we briefly survey the link between these subjects
Indeks glikemik donat dengan beberapa jenis topping
No full textIndeks glikemik adalah metode kuantitatif untuk menggambarkan kemampuan karbohidrat suatu makanan dalam menaikkan glukosa darah, diperoleh dengan membandingkan luas area di bawah kurva respon glukosa darah makanan uji dengan makanan standar. Tujuan dari penelitian ini adalah mengetahui indeks glikemik donat dengan beberapa jenis topping. Responden dalam penelitian ini berjumlah sepuluh orang sehat dengan indeks massa tubuh (IMT) normal dan tidak memiliki gangguan metabolisme glukosa. Pemeriksaan glukosa darah dilakukan sebelum diberikan makanan uji dan selama dua jam sesudahnya. Setelah pengolahan dan penghitungan data didapatkan rerata indeks glikemik. Urutan donat dengan indeks glikemik dari yang tertinggi adalah donat topping gula tepung (98,12%), topping sereal (97,22%), dan topping coklat (89,28%). Ketiga donat dengan tiga toping yang diuji termasuk dalam makanan IG tinggi. Hasil penelitian ini menyimpulkan terdapat perbedaan bermakna antara indeks glikemik makanan standar dengan donat toping gula tepung, dan antara donat toping gula tepung dengan toping coklat, berdasarkan uji statistik dengan Repeated Anova (p val.u
Image_1_Effects of topping and non-topping on growth-regulating hormones of flue-cured tobacco (Nicotiana tabacum L.)—a proteomic analysis.jpeg
No full textIntroductionUntil now, the mechanism underlying the impact of topping on hormone regulation in tobacco plants remains unclear, and most studies investigating the hormone signaling pathways in plants rely on genes or transcriptional pathways.MethodsThis study examines the regulatory mechanisms of hormones in the roots and leaves of tobacco plants with and without topping at the protein level.ResultsThe results demonstrate that, compared with non-topped plants, topping leads to a decrease in the levels of IAA (auxin), ABA (abscisic acid), and GA (gibberellin) hormones in the leaves, whereas the content of the JA (jasmonic acid) hormone increases. Furthermore, in the roots, topping results in an increase in the levels of IAA, ABA, and JA hormones, along with a decrease in GA content. In the leaves, a total of 258 significantly different proteins were identified before and after topping, with 128 proteins upregulated and 130 proteins downregulated. In the roots, there were 439 proteins with significantly different quantities before and after topping, consisting of 211 upregulated proteins and 228 downregulated proteins. Notably, these proteins were closely associated with the metabolic and biosynthetic pathways of secondary metabolites, as indicated by functional categorization.ConclusionsWhen integrating the hormone changes and the proteomics results, it is evident that topping leads to increased metabolic activity and enhanced hormone synthesis in the root system. This research provides a theoretical foundation for further investigations into the regulation and signaling mechanisms of hormones at the protein level before and after topping in plants.</p
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