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Field pennycress (Thlaspi arvense) is a new biofuel winter annual crop with extreme cold hardiness and a short life cycle, enabling off-season integration into corn and soybean rotations across the U.S. Midwest. Pennycress fields are susceptible to winter snow melt and spring rainfall, leading to waterlogged soils. The objective of this research was to determine the extent to which waterlogging during the reproductive stage affected gene expression, morphology, physiology, recovery, and yield between two pennycress lines (SP32-10 and MN106). In a controlled environment, total pod number, shoot/root dry weight, and total seed count/weight were significantly reduced in SP32-10 in response to waterlogging, whereas primary branch number, shoot dry weight, and single seed weight were significantly reduced in MN106. This indicated waterlogging had a greater negative impact on seed yield in SP32-10 than MN106. We compared the transcriptomic response of SP32-10 and MN106 to determine the gene expression patterns underlying these different responses to seven days of waterlogging. The number of differentially expressed genes (DEGs) between waterlogged and control roots were doubled in MN106 (3,424) compared to SP32-10 (1,767). Functional enrichment analysis of upregulated DEGs revealed Gene Ontology (GO) terms associated with hypoxia and decreased oxygen, with genes in these categories encoding proteins involved in alcoholic fermentation and glycolysis. Additionally, downregulated DEGs revealed GO terms associated with cell wall biogenesis and suberin biosynthesis, indicating suppressed growth and energy conservation. Interestingly, MN106 waterlogged roots exhibited significant stronger regulation of these genes than SP32-10, displaying a more robust transcriptomic response overall. Together, these results reveal the reconfiguration of cellular and metabolic processes in response to the severe energy crisis invoked by waterlogging in pennycress. [ABSTRACT FROM AUTHOR]

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In spur gears, the maximum bending stress concentration is known to occur in the gear tooth fillet region. This study focuses on the geometric optimization of symmetric involute gears to alleviate stress concentrations near the fillet. Stress relief is achieved by incorporating strategically placed holes and semi-circular cuts in the area between adjacent teeth. The size and location of these features are varied to reduce bending stresses, leading to increased load capacity, extended gear lifetime, reduced manufacturing costs, and minimized noise and vibration. Finite element methods are employed to formulate and model spur gears, followed by a geometric optimization process to achieve the desired stress distribution. Two-dimensional modeling is utilized based on gear engagement theories, taking advantage of ANSYS Mechanical APDL 2020 R1 and optimization tools. The gear geometry is modified to redistribute stress in high-stress regions, optimizing the power transmission capacity and reducing costs. The current finite element formulation is validated through numerical examples and by comparing the results with those obtained from ANSYS. The optimization process results in a 25% reduction in stress concentration, enhancing the gear's load-carrying capacity. [ABSTRACT FROM AUTHOR]

In this paper, root stress, manufacturing possibilities and limitations of standard and nonstandard tooth root fillet of spur gears are examined. Nowadays, standard trochoidal root fillet is used the most as an economical trade-off between tooth strength and manufacturing complexity. A disadvantage of the trochoidal root fillet, especially in spur gears with less than 17 teeth, is undercutting which minimises strength of tooth root, introduces stress concentration, and deteriorates meshing conditions. This study focuses on different root designs, namely elliptical and novel cycloidal root fillets. Root stress in gears with different root designs is analysed by FEM and compared with analytical equations according to ISO. The possibility of producing nonstandard root fillet gears by hobbing and limitations of surface finishing are considered as well. Analysis reveals stress differences between each of the root fillet shapes and their relative advantages and disadvantages. [ABSTRACT FROM AUTHOR]

Field pennycress ( Thlaspi arvense ) is a new biofuel winter annual crop with extreme cold hardiness and a short life cycle, enabling off-season integration into corn and soybean rotations across the U.S. Midwest. Pennycress fields are susceptible to winter snow melt and spring rainfall, leading to waterlogged soils. The objective of this research was to determine the extent to which waterlogging during the reproductive stage affected gene expression, morphology, physiology, recovery, and yield between two pennycress lines (SP32-10 and MN106). In a controlled environment, total pod number, shoot/root dry weight, and total seed count/weight were significantly reduced in SP32-10 in response to waterlogging, whereas primary branch number, shoot dry weight, and single seed weight were significantly reduced in MN106. This indicated waterlogging had a greater negative impact on seed yield in SP32-10 than MN106. We compared the transcriptomic response of SP32-10 and MN106 to determine the gene expression patterns underlying these different responses to seven days of waterlogging. The number of differentially expressed genes (DEGs) between waterlogged and control roots were doubled in MN106 (3,424) compared to SP32-10 (1,767). Functional enrichment analysis of upregulated DEGs revealed Gene Ontology (GO) terms associated with hypoxia and decreased oxygen, with genes in these categories encoding proteins involved in alcoholic fermentation and glycolysis. Additionally, downregulated DEGs revealed GO terms associated with cell wall biogenesis and suberin biosynthesis, indicating suppressed growth and energy conservation. Interestingly, MN106 waterlogged roots exhibited significant stronger regulation of these genes than SP32-10, displaying a more robust transcriptomic response overall. Together, these results reveal the reconfiguration of cellular and metabolic processes in response to the severe energy crisis invoked by waterlogging in pennycress., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Combs-Giroir, Shah, Chhetri, Morgan, Prates, Townsend, Phippen, Phippen, Jacobson and Gschwend.)

Gear roll forming process is an innovative near-net-shape gear manufacturing technology for efficient manufacturing, high material utilization rate, high products strength, and outstanding surface quality. The profile of the Tooth of the Rolling Tool (TRT) has a direct impact on its strength/stiffness which further affects its life duration and the accuracy of the formed products. Research has been carried out to design the involute curve of TRT, however, the transaction curve of TRT which also has a significant impact on tooth strength and service durability remains to be designed and optimized in order to further improve the rolling performance. In this paper, an elliptical gear tooth root transaction curve is proposed to replace the traditional fillet curve for the enhancement of tooth bending performance. The maximum root stress and stiffness of the gear tooth with elliptical transaction curve are calculated and compared to the standard profile with different parameters (modulus, pressure angle, and coefficient of bottom clearance). The results show that proposed elliptical tooth reduces the maximum root stress and increase the strength and stiffness of TRT especially significant for rolling tools with small number of teeth and coefficient of bottom clearance. [ABSTRACT FROM AUTHOR]

As lined, higher transmission ratio drives system will have uneven stresses in the root region of the pinion and wheel. To enrich this agility of uneven stresses in normal-contact ratio (NCR) gearing system, an enhanced system is desirable to be industrialized. To attain this objective, it is proposed to put on the idea of modifying the correction factor in such a manner that the bending strength of the gearing system is improved. In this work, the correction factor is modified in such a way that the stress in the root region is equalized between the pinion and wheel. This equalization of stresses is carried out by providing a correction factor in three circumstances: in pinion; wheel and both the pinion and the wheel. Henceforth performances of this S+, S0 and S- drives are evaluated in finite element analysis (FEA) and compared for balanced root stresses in parallel shaft spur gearing systems. It is seen that the outcomes gained from the modified drive have enhanced performance than the standard drive.

The design of gears and gear drives are becoming challenging in automobile applications in which low contact ratio gears are required to transmit higher loads and be lighter in weight. There are various methods available for optimizing the design. Some researches have been taken place in the areas of gear tooth profile modifications for providing internal stress relief and weight reduction. In most cases, the maximum loads are assumed to be acting on the tip of the tooth. In this study, investigations are carried out on the effect of circular discontinuity on the weight reduction without affecting the root stress. The maximum tangential load is applied on the highest point of single tooth contact. The results show that with the modified gear tooth having a combination of two circular discontinuities of size 0.4 times the module not only provides weight reduction but also gives stress relief at the root. [ABSTRACT FROM AUTHOR]

Straipsnyje aptariami Lietuvos TSR upių ir ežerų vardyne (1963) ir A. Vanago veikaluose Lietuvos TSR hidronimų daryba (1970), Lietuvių hidronimų etimologinis žodynas (1981) fiksuoti šakninio (1 akcentinė paradigma) ir kilnojamojo (3a ar 3b akcentinė paradigma) kirčiavimo variantus turintys hidronimai. Analizuojamos 18-iolikos vandenvardžių su priesagomis -ainys/-ainis, -elis/-elys, -enys/-enis, -ija, -ikė/-ikis/-ikys, -inis/-inys, -mena, -ula/-ulė (ir -ala/-alas), -ulis/-ulys, -(i)uva, -uvis/-uvys, -užis/-užys galimos dvejopo kirčiavimo priežastys: senovinio kirčiavimo reliktai, akcentinės pamatinių žodžių savybės, tarminis kirčiavimas, kitų priesaginių vedinių kirčiavimo analogija ir kt.

Splined joints are commonly used to transmit rotary motion from a shaft to machine elements such as gears. While computationally efficient spline load distribution models have recently been proposed, there is no validated load distribution model of a splined joint due to lack of high-fidelity experimental data. Accordingly, this study aims to establish an extensive experimental database on load distributions of splined joints subject to both spur and helical gear loading conditions. A quasi-static, spline-specific test setup is developed and instrumented. A test matrix covering various loading conditions is executed in order to form a spline load distribution database. The experimental data illustrates the cyclic nature of loads and resultant stresses on spline teeth caused by rotation of the spline teeth in relation to the gear mesh that loads the splined joint. A nonlinear relationship between torque applied and resultant stress is revealed, as well as the relationship between the location of maximum stress along the face width and the amount of lead crown modification applied. Lastly, simulation results from the model of Hong et al. (2014b) are compared to the experimental data under spur and helical gear loading conditions to assess the premise of such models.

This paper carries out the experimental and numerical investigations on the root stress of a light-load spur gear drive. An improved gear test rig is developed to enable the dynamic root stress of a light-load spur gear drive to be wirelessly measured, and the signals of root strain, rotational speeds and torques of input/output gear shafts are sent or received wirelessly. After the random electrical noise is eliminated by multi-point average method, the key parameters of dynamic contact analysis on the root stress (rotational speeds and torque) are obtained, and the root strain signal is converted into root stress. Based on the curve of the measured root stress, the impact of meshing teeth and the alternative variation in the single and double pair gear meshing can be attained quantitatively. The geometric model of gear is developed by the generative machining principle and the coordinate transformation method. Then, the dynamic contact analysis is performed by the display centre difference method to obtain the maximum tensile stress of the tooth root, which is compared with the results in literature as well as the wireless measurement data. It shows that the wireless measurement approach and the developed method of dynamic contact analysis are effective and efficient. [ABSTRACT FROM PUBLISHER]

Gear rattle is a major noise problem in certain powertrains systems, especially those that are driven by internal combustion engines such as timing gear drives, engine balancers or manual transmissions. Teeth lose contact intermittently to commit impacts along the drive and coast sides of the gear pairs having backlash. Most of the studies on this topic focused exclusively on the noise and vibration consequences of rattle with a very little attention given to its influence on system durability. This study presents an experimental investigation of tooth root stresses of a spur gear pair during periodic and chaotic rattling motions caused by a harmonically time-varying input torque. Root stresses of certain teeth of one of the gears are measured in the instances when these teeth are in gear mesh zone when impacts occur. Changes to root stress time histories due to drive and coast-side impacts are documented to show that root stress amplitudes are increased significantly by impacts. Measurements also indicate that most impacts generate families of fully-released strain peaks that contribute the fatigue damage along the drive and coast sides root fillets. A deformable-body model was shown to simulate the experiments accurately, so that it can be used to predict statistical distributions for root stress duty cycles for estimation of fatigue lives of rattling gears. [ABSTRACT FROM AUTHOR]

Background and Aims: Root anchorage function is crucial for tree survival as most trees are exposed to recurrent wind throughout their lifespan. Trees exhibit a large variability of root system architecture (RSA) due genetic and environmental factors. This study aims to understand the links between RSA and tree stability. Methods: A 3D biomechanical model was used to simulate tree overturning. To capture the variability of sinker RSA, fourteen virtual root patterns were created from an ensemble average of measured Pinus pinaster root systems. Root virtual patterns and tree-pulling simulations were verified against experimental data. Results: The model predicts realistic tree anchorage strength, root stress, and failure patterns. Only a few root components contribute significantly to anchorage strength. The taproot contributes the most to anchorage rigidity, representing 61 % of the anchorage strength. The windward roots failure drives ultimate anchorage failure, representing 25 % of the anchorage strength. Simulations show that root secondary thickening induces higher anchorage rigidity and increases anchorage strength by 58 %. Conclusions: This innovative approach appears promising for describing tree stability and its acclimation to external constraints. [ABSTRACT FROM AUTHOR]

Alleviation of Al rhizotoxicity by Ca and Mg can differ among species and genotypes. Root elongation of soybean [Glycine max (L.) Merr.] line N93-S-179 and cvs. Young and Ransom exposed to varying concentrations of Al, Ca and Mg were compared in two experiments using a vertically split root system. Roots extending from a surface compartment with limed soil grew for 12 days into a subsurface compartment with nutrient solution treatments maintained at pH 4.6 with either 0 or 15 µmol L-1 Al. Calcium and Mg concentrations in treatments ranging from 0 to 20 mmol L-1. Although an adequate supply of Mg was provided in the surface soil compartment for soybean top growth, an inclusion of Mg was necessary in the subsurface solutions to promote root elongation in both the presence and absence of Al. In the absence of Al in the subsurface solution, tap root length increased by 74 % and lateral root length tripled when Mg in the solutions was increased from 0 to either 2 or 10 mmol L-1. In the presence of 15 µmol L-1 Al, additions of 2 or 10 mmol L-1 Mg increased tap root length fourfold and lateral root length by a factor of 65. This high efficacy of Mg may have masked differences in Al tolerance between genotypes N93 and Young. Magnesium was more effective than Ca in alleviating Al rhizotoxicity, and its ameliorative properties could not be accounted for by estimated electrostatic changes in root membrane potential and Al3+ activity at the root surface. The physiological mechanisms of Mg alleviation of Al injury in roots, however, are not known.A redução na rizotoxidez de Al por Ca e Mg difere entre espécies e genótipos. A elongação radicular da linhagem N93-S-179 e cvs. Young e Ransom de soja [Glycine max (L.) Merr.] exposta a concentrações variáveis de Al, Ca e Mg foi comparada em dois experimentos, usando um sistema de raízes subdivididas verticalmente. As raízes cresceram por 12 dias a partir de um compartimento superficial com solo corrigido para um compartimento subsuperficial com soluções nutritivas que continha os tratamentos e mantidas a pH 4,6. As concentrações de Ca e Mg nos tratamentos variaram de 0 a 20 mmol L-1. Embora tenha sido providenciado um suprimento adequado de Mg para o crescimento da parte aérea da soja no compartimento superficial com solo, a adição de Mg nas soluções subsuperficiais foi necessária para promover a elongação radicular tanto na presença como na ausência de Al. Na ausência de Al na solução em subsuperfície, o comprimento de raízes aumentou 74 % e o comprimento das raízes laterais triplicou quando Mg da solução foi aumentado de 0 para 2 ou 10 mmol L-1. Na presença de 15 µmol L-1 de Al, adições de 2 ou 10 mmol L-1 de Mg aumentaram o crescimento da raiz principal em quatro vezes e das raízes laterais por uma fator de 65. Esta elevada eficiência do Mg pode ter mascarado as diferenças na tolerância ao Al entre os genótipos N93 e Young. O Mg foi mais eficiente que o Ca para reduzir a rizotoxidez do Al, e sua propriedade protetora não pode ser explicada pelas mudanças eletrostáticas estimadas para o potencial da membrana e atividade do Al3+ na superfície da raiz. No entanto, os mecanismos fisiológicos envolvidos no efeito protetor do Mg contra a toxidez do Al às raízes ainda não são conhecidos.

A simplified analysis is presented in order to evaluate the influence of the profile modifications minimising transmission error time-variations on some other key design criteria such as mesh forces, stresses and tooth friction losses. A unique equation for the set of profile modification rendering transmission error nearly constant is presented and a number of original stress and loss factor closed-form formulae are derived whose results compare very well with those obtained by numerical simulations. Some general results are then deduced about the evolutions of the design criteria with regard to optimum relief parameters which are believed to be useful at the early stage of profile modification design. [ABSTRACT FROM AUTHOR]

Abstract: For increasing the load carrying capacity of geared power transmissions several tooth designs alternative to the standard involute have been proposed. The use of non-involute teeth has a number of disadvantages and for this reason asymmetric involute-type teeth have been studied as a promising alternative. In this paper the idea of one-sided involute asymmetric spur gear teeth is introduced to increase load carrying capacity and combine the good meshing properties of the driving involute and the increased strength of non-involute curves. These novel teeth are intended for constant direction of rotation although they can be used in a limited way for reverse rotation. Both flanks are fully generated by a hob, the design of which is also investigated. The increase in load carrying capacity can reach up to 28% compared to the standard 20° involute teeth. [Copyright &y& Elsevier]

For increasing the load carrying capacity of geared power transmissions several tooth designs alternative to the standard involute have been proposed. The use of non-involute teeth has a number of disadvantages and for this reason asymmetric involute-type teeth have been studied as a promising alternative. In this article the idea of one-sided involute asymmetric spur gear teeth is introduced to increase load carrying capacity and combine the good meshing properties of the driving involute and the increased strength of non-involute curves. These novel teeth are intended for constant direction of rotation, although they can be used in a limited way for reverse rotation. Both profiles are fully generated by a hob, the design of which is also investigated. The increase in load carrying capacity can reach up to 28{%} compared to the standard 20° involute teeth. [ABSTRACT FROM AUTHOR]

Abstract: This paper investigates effect of addendum on tooth contact strength, bending strength and basic performance parameters of spur gears. Face-contact model of teeth, mathematical programming method (MPM) and three-dimensional (3D), finite element method (FEM) are used together to conduct loaded tooth contact analyses (LTCA), deformation and stress calculations of spur gears with different addendums and contact ratios. Tooth load, load-sharing rate, contact stress, root bending stress, transmission error and mesh stiffness of the spur gears are analyzed. Effects of addendum and contact ratio on gear strength and basic performance parameters are also discussed. It is found that contact stress distributed on tooth surface along the profile is asymmetrical around the geometrical contact point of the gears when the geometrical contact point is far away from the pitch point, especially at the tip or root contacts. The maximum contact stress is also not exactly at the geometrical contact point. Hertz formula can only calculate the tooth contact stress approximately. FEM can be used to conduct precise analysis of the tooth contact stress. It is also found that increment of addendum can increase number of contact teeth, then this increment can reduce tooth contact stress and root bending stress, generally speaking. But this increment also makes the tooth depth long and lets the tooth be deformed easily. So, this increment can reduce tooth contact stress, but there is no guarantee that this increment can certainly reduce tooth root bending stress. Also, increment of the addendum makes the values of “T” and “V” in the so-called value of “PVT” great. So, scoring strength calculations of the tooth tip and root becomes more important when to use high contact ratio gears (HCRG) with long addendum. Finally, strength calculations of HCRG with misalignment error, lead crowning and thin-walled thickness are discussed simply in this paper. [Copyright &y& Elsevier]

Aim To examine the effect of specific tapers on root stresses and thus vertical root fracture. Methodology The effect of taper on root stresses was calculated during simulated warm vertical compaction of gutta-percha in a straight rooted premolar for three tapers (0.04, 0.06 and 0.12 mm mm-1) using finite element analysis. Stresses in the dentine were observed whilst the root was filled with three subsequent gutta-percha increments. Each increment was compacted at 10 or 15 N and the gutta-percha cooled down to 37 °C. After filling, composite was polymerized in the access space. A functional occlusal load of 50 N was then applied on the buccal cusp incline. The stress distribution in the root during the occlusal loading was compared with the stresses during filling. Results During filling, the highest stresses were found: (a) at the canal surface; (b) using the smallest taper; (c) in the apical third; and (d) during the first gutta-percha increment. The root stress distribution changed when the functional post-filling load was applied. It generated the highest stresses at the external root surface, with a tensile stress concentration at the lingual surface of the cervical third. Since the stresses during simulated masticatory loading concentrated on the external surface, an increased taper size caused only slightly higher root stress levels. Conclusions With increasing taper, root stresses decreased during root filling but tended to increase for masticatory loading. Root fracture originating at the apical third is likely initiated during filling, whilst fracture originating in the cervical portion is likely caused by occlusal loads. [ABSTRACT FROM AUTHOR]

• The tip contour of a protuberance hob is defined in detail by a Bezier curve with six parameters. • Hob tip contour is optimized for increasing the bending capacity of gear tooth root. • A best set of Bezier curve parameters for usually standard hobs is found out for reducing the tooth root stress. • A best set of Bezier curve parameters for protuberance hobs is found out for reducing the tooth root stress. • These two sets of parameters are widely applicable to all common gear cases. Optimising the hob used to manufacture gears is an attractive approach for minimizing the gear tooth root stress. However, currently available approaches often require modifying the hob for every gear case, which limits their practical application and increases design and manufacturing costs. In this study, two sets of Bezier curve parameters for gear hobs were developed to minimize the tooth root stress: one for standard hobs and the other for protuberance hobs. The two parameter sets can be used to modify any hob and effectively reduce the gear bending stress, and they are widely applicable to all common gear cases. Calculation with the finite element method indicated that the first-best parameter set for standard hobs reduced the stress of most gear cases by 6%–10%. The second-best parameter set for protuberance hobs reduced the stress of almost all gear cases by 7%–15%. The average optimisation potential was 10.73%. Meanwhile, the manufacturing cost is very low because an optimised hob can be applied to producing other gears. These two parameter sets are a significant contribution to the optimisation and manufacture of gears. [ABSTRACT FROM AUTHOR]