Design and dynamics calculations of shallot seed feeding mechanism

Research on shallot planting feeding technology is an integral part of the shallot planter associations in which determines the suitable drop of shallot seeds to the planting mechanism. The shape of shallot seed will affect the process of selecting the feeding mechanism and feeding funnel shape. The dynamics study of shallot seeds in the feeding funnel and their movement (that is dependent on the profile and mass property of seeds) is important for manufacturing and running a good mechanism. The shallots will then be transferred by the feeding mechanism to the planting mechanism with a suitable falling trajectory. In this research, design and calculation of dynamics of the feeding mechanism of the shallot seeds is investigated using dynamics equations and also Autodesk Inventor Professional and Matlab Simulink codes. The suitable ranges of feeding mechanism parameters are obtained for the analyzed shallot seeds in terms of the specific shape, weight and mass center coordinates of the seeds.

Effect of joint stiffness and flexibility on the design of reinforced cement concrete structure

Relevance. A beam-column joint is a crucial zone in any frame structure that transmits the forces at the end of the members in the panel zone. The connection between the joints may be assumed as rigid or flexible one and it is not an ideal one to predict the actual behavior of the joint section. Methods. The displacement along the joint section is the most critical one that has to be taken care while designing the structure. In this paper, the flexibility of the reinforced concrete joints was studied under two different cases: in first phase, building having 3 storey including ground floor was taken and is analysed using SAP 2000 and secondly third floor shear wall with l hollow concrete mesh of column section was analyzed in same software and the flexibility of the joints was tested in terms of its stress and displacement parameters using different approaches such as link mass property, end length offset zone, panel zone rotational spring stiffness property. The results obtained from the two cases were analyzed with consideration of parametric study and variation of the stresses with displacement and are shown with comparative graphic.

The Eu:CROPIS Mass Property Campaign: Trimming a Spin-Stabilized Compact Satellite for a Long-Term Artificial Gravity Experiment

Eu:CROPIS (Euglena Combined Regenerative Organic Food Production in Space) is the first mission of DLR’s compact satellite program. The launch of Eu:CROPIS took place on December 3rd in 2018 on-board the Falcon 9 SSO-A mission. The satellite’s primary payload Eu:CROPIS features a biological experiment in the context of closed loop coupled life support systems. The Eu:CROPIS satellite mission uses spin stabilization along its Z -axis to provide defined acceleration levels for the primary and secondary payloads to simulate either a Moon or Mars gravity environment. For the payload performance, it is vital to achieve a minimum deviation between spacecraft Z -axis and the major moment of inertia (MoI) axis to minimize the offset of the envisaged acceleration levels. Specific moment of inertia ratios between the spin- and minor axes had to be maintained to allow the attitude control system to keep the satellite at a stable rotation despite environmental disturbances. This paper presents the adaptive and flexible trimming strategy applied during the flight model production, as well as the mass property measurement acceptance campaign and the respective results.

Examination of the effects of non-measurable explanatory variables on the value of real estate in the process of mass valuation of land

The paper proposes a solution to the problem of how to introduce non- -measurable features (attributes) of a property that significantly affect its value to the process of its valuation. The authors adopt two measures enabling them to study the influence of order features on the value of property, the Spearman rank coefficients and standardized ßk coefficients, and proceed to check their efficiency, applying an algorithm of mass property valuation (SAMWN) to the sample of 567 plots of land in Szczecin designated for housing purposes. The results thus obtained are then compared with the valuations of these plots of land performed by property appraisers. The study demonstrates that lower valuation errors are obtained when using standardized ßk coefficients than the Spearman rank coefficients.

Lower rotational inertia and larger leg muscles indicate more rapid turns in tyrannosaurids than in other large theropods

Synopsis Tyrannosaurid dinosaurs had large preserved leg muscle attachments and low rotational inertia relative to their body mass, indicating that they could turn more quickly than other large theropods. Methods To compare turning capability in theropods, we regressed agility estimates against body mass, incorporating superellipse-based modeled mass, centers of mass, and rotational inertia (mass moment of inertia). Muscle force relative to body mass is a direct correlate of agility in humans, and torque gives potential angular acceleration. Agility scores therefore include rotational inertia values divided by proxies for (1) muscle force (ilium area and estimates of m. caudofemoralis longus cross-section), and (2) musculoskeletal torque. Phylogenetic ANCOVA (phylANCOVA) allow assessment of differences in agility between tyrannosaurids and non-tyrannosaurid theropods (accounting for both ontogeny and phylogeny). We applied conditional error probabilities a(p) to stringently test the null hypothesis of equal agility. Results Tyrannosaurids consistently have agility index magnitudes twice those of allosauroids and some other theropods of equivalent mass, turning the body with both legs planted or pivoting over a stance leg. PhylANCOVA demonstrates definitively greater agilities in tyrannosaurids, and phylogeny explains nearly all covariance. Mass property results are consistent with those of other studies based on skeletal mounts, and between different figure-based methods (our main mathematical slicing procedures, lofted 3D computer models, and simplified graphical double integration). Implications The capacity for relatively rapid turns in tyrannosaurids is ecologically intriguing in light of their monopolization of large (>400 kg), toothed dinosaurian predator niches in their habitats.

Novel robust controller design for load sway reduction in double-pendulum overhead cranes

It is seen that when the hook mass is larger than the load mass or the load has distributed mass property, the load sway of the crane system presents as double-pendulum effect. In this situation, crane system has two different natural frequencies so that the sway characteristic becomes more complex and greatly increases the difficulty of the dynamic performance analysis and controller design. Moreover, the rope length changes significantly affect the stability and control performance of the crane system. In order to solve the aforementioned problems, the linear dynamics of a two-dimensional overhead crane with double-pendulum effect is derived based on a disturbance observer, and is decoupled for controller design by modal analysis. Next, a state feedback controller is presented to achieve robust control performance for a given range of rope length changes. The controller gains are obtained via linear matrix inequality optimization method. Finally, numerical simulations and experimental results validate that the proposed method has superior control performance.