On Parametric Study of Liquid Leaves from Spoked Wheel Inlet

Danish Spoked Wheels In recent years, attention has on several occasions been drawn to disc wheels found in Denmark. New dating and the work of the Dutch archaeologist D. van der Waals have given rise to new interpretations. The present article is concerned with another group of wheels -mainly in the collections of the National Museum of Denmark- namely wheels with 8 or more spokes. The author has based his treatment of these excavated wheels on ethnological studies of the dying trades of the wheelwright and coach-builder.The main characteristic of the modem spoked wheel is its conical form or camber, arising from the spokes being set obliquely in the hub away from the vehicle. The way certain components are assembled is also characteristic. The spokes are thus fixed in holes in the hub and in holes in the felloes. The identical felloes are shaped to follow the circumference of the wheel and are held together by dowels.The wheel is shown to be subject not so much to compressive strains as to ultimate strains, since the strongest and most frequent forces are transmitted laterally. In contrast to the disc wheel, the spoked wheel is in principle equally strong, whichever part of the rim is in contact with the ground. With its better use of the natural directional strength of the wood, the spoked wheel also permits a considerable saving in weight. The camber of the modem wheel serves to reduce the constructional weakness of the spoked wheel. The breaking strength at the junction of hub and spokes is low, and when a wheel receives its greatest lateral strain running on a sloping sw-face, the lower wheel will also have to bear the largest part of the weight of the vehicle. Figs. 2 and 5 show how the cambered wheel absorbs this lateral strain.The oldest known spoked wheels from c. 2000 B.C. were found in Mesopotamia, in connection with two-wheeled carriages. The spoked wheel apparently spread through Europe with the two-wheeled chariot and reached Scandinavia in the course of about five hundred years. Only very few of these early spoked wheels, which are mainly known from pictures, have been preserved. It does not seem to be possible to establish a connection with the later tradition. The many waggon graves of the Hallstatt period in Central Europe point, however, in the sporadic cases where details of construction can be ascertained, to a more recent tradition, at least to the finds of the La Tene period where, for instance, the Danish Dejbjerg waggons are extremely well preserved. In the Dejbjerg waggons a relatively high number of spokes, 12-14, appears for the first time, 800-900 years after a high spoke-number was usual in China. Apparently, the chariot spread quite rapidly in Asia also, and finds from China from c. 1300 B.C. show these vehicles with high wheels, turned spokes, and a spoke number up to 26. A cultural connection between eastern Asia and Europe in the Hallstatt period has been demonstrated, and the author sees the waggon finds of the La Tene period in the light of this connection.The 4-wheeled waggon later becomes the favoured means of agricultural transport in continental Europe and the first intimations of more humble wheels of this type are found among the Østfold petroglyphs, in groups assigned to 650-400 B.C., or in the find from Rappendam in northern Zealand where large numbers of disc wheels were found amongst several presumed long-waggons. At about the beginning of our era, however, the disc wheel seems to have been replaced by spoked wheels, also for heavy transport. A new, very simple type of many-spoked wheel now turns up in the north European finds.The excavated wheels in the prehistoric collection of the National Museum are unrepresentative and undated and any conclusions must necessarily be treated with reservation. It is possible to divide these wheels into 3 groups, the first two of which are clearly defined, whilst the third, which largely comprises the remaining wheels, shows certain common features. Group I is characterized by hub shape 1 (fig. 12), 8 or 12 spokes, but always 4 felloes. The spoke-tenons in the hub are flat and rectangular but without a shoulder at the transition to the round shaft of the spoke. Group II comprises wheels with hub form 2, and 12 spokes and 6 felloes, which in contrast to those of group I are decorated with concentric mouldings on one or both sides. The wheels of group III have 10 or 12 spokes (always 2 in each felloe). The felloes are undecorated and have wear pins let into the tread. Diagram p applies this classification to the wheels in question.The wheel parts of group I stem mainly from an Iron Age deposition in Tranbær bog, with a few parallels, one of which is from the Vimose find. The individual finds in the other groups are very difficult to date, but the sum of available information, supported by analogies in the other Scandinavian countries and in northern Europe, seems to suggest that the grouping employed also has chronological validity.All the wheels in the prehistoric collection of the National Museum lack the characteristic camber of the modern wheel. The oldest Danish wheel exhibiting this feature is in the medieval collection and was found in the excavation of Boringholm castle. The remains of several cambered wheels were found there and are presumed to belong to the period of the castle, which is believed to have been built around 1300 and relinquished no more than a century later.Examination of technical details in construction seems to support the view that the classification employed has chronological validity, and it can be demonstrated that the mode of assembly in those wheels which are thought to be the oldest is not the same as in the later wheels where components are assembled in the same order as in modem wheelwrighting.In conclusion, it may be pointed out that several important details and innovations in the form and manufacture of the wheel can be dated earlier in China than in Europe. This is true of the modem method of assembly, which was known in China in 1300 B.C. and of the camber, which was mentioned in China in 200 B.C., together with the entire iron rim around the wheel, which although known in Europe in the Hallstatt period, was forgotten, to appear again around 1800.Torben Witt

A theoretical study of the stress in a spoked wheel produced by horizontal load was made in the second report by one of the writers. In succesion to this study, they made the following studies. (a) Experimental studies of the stress, by making use of a set of axle and spoked wheels which has suitable dimensions for the comparison of calculated and experimental values of stress. (b) The comparison between the calculated and experimental results of stress in the spoked wheel caused by a horizontal load. In this study, the calculation of the stress is made applying the theoretical equations and numerical results in the second report. (c) Experimental and theoretical studies of the axle deflection and the change of back-gauge when the horizontal load acts on the spoked wheel axle. As the results of these studies the following conclusions can be reached. (1) Experimental values of stresses in spokes under the horizontal load accord with the calculated values. With this fact, it is clear that previously made theoretical study of this problem is correct. (2) Experimental values of the axle deflection and the change of back-gauge accord with the calculated values approximately. But we have no objection to using the calculated values, that is, we can find the horizontal load by means of measuring the change of back-gauge.

In waterlogged soil, deficiency of oxygen triggers development of aerenchyma in roots which facilitates gas diffusion between roots and the aerial environment. However, in contrast to other monocots, roots of rice (Oryza sativa L.) constitutively form aerenchyma even in aerobic conditions. The formation of cortical aerenchyma in roots is thought to occur by either lysigeny or schizogeny. Schizogenous aerenchyma is developed without cortical cell death. However, lysigenous gas-spaces are formed as a consequence of senescence of specific cells in primary cortex followed by their death due to autolysis. In the last stage of aerenchyma formation, a 'spoked wheel' arrangement is observed in the cortical region of root. Ultrastructural studies show that cell death is constitutive and no characteristic cell structural differentiation takes place in the dying cells with respect to surrounding cells. Cell collapse initiation occurs in the center of the cortical tissues which are characterized by shorter with radically enlarged diameter. Then, cell death proceeds by acidification of cytoplasm followed by rupturing of plasma membrane, loss of cellular contents and cell wall degradation, while cells nuclei remain intact. Dying cells releases a signal through symplast which initiates cell death in neighboring cells. During early stages, middle lamella-degenerating enzymes are synthesized in the rough endoplasmic reticulum which are transported through dictyosome and discharged through plasmalemma beneath the cell wall. In rice several features of root aerenchyma formation are analogous to a gene regulated developmental process called programmed cell death (PCD), for instance, specific cortical cell death, obligate production of aerenchyma under environmental stresses and early changes in nuclear structure which includes clumping of chromatin, fragmentation, disruption of nuclear membrane and apparent engulfment by the vacuole. These processes are followed by crenulation of plasma membrane, formation of electron-lucent regions in the cytoplasm, tonoplast disintegration, organellar swelling and disruption, loss of cytoplasmic contents, and collapse of cell. Many processes in lysing cells are structural features of apoptosis, but certain characteristics of apoptosis i.e., pycnosis of the nucleus, plasma membrane blebbing, and apoptotic bodies formation are still lacking and thus classified as non-apoptotic PCD. This review article, describes most recent observations alike to PCD involved in aerenchyma formation and their systematic distributions in rice roots.

A theoretical study of the stress in a spoked wheel produced by horizontal load was made in the second report by one of the writers. In succesion to this study, they made the following studies. (a) Experimental studies of the stress, by making use of a set of axle and spoked wheels which has suitable dimensions for the comparison of calculated and experimental values of stress. (b) The comparison between the calculated and experimental results of stress in the spoked wheel caused by a horizontal load. In this study, the calculation of the stress is made applying the theoretical equations and numerical results in the second report. (c) Experimental and theoretical studies of the axle deflection and the change of back-gauge when the horizontal load acts on the spoked wheel axle. As the results of these studies the following conclusions can be reached. (1) Experimental values of stresses in spokes under the horizontal load accord with the calculated values. With this fact, it is clear that previously made theoretical study of this problem is correct. (2) Experimental values of the axle deflection and the change of back-gauge accord with the calculated values approximately. But we have no objection to using the calculated values, that is, we can find the horizontal load by means of measuring the change of back-gauge.

The wheelbarrow as a simple means for transporting goods has been used across much of Eurasia. The vehicle usually consists of a relatively small wheel that is mounted beneath a frame for the load. The wheel is usually placed in front or under the front part of the frame, which extends into two handles by which the barrow is lifted up and pushed. On the basis of pictorial evidence from medieval Europe, it is assumed that the wheelbarrow was developed as a labor-saving device in which one of two men needed for carrying a carrying load was replaced by a wheel (Matties, 1991). Due to the fact that the workman had to lift part of the weight of the load, the wheelbarrow was typically restricted to short distances. In China, the wheelbarrow is documented in pictorial sources from the first century BCE. The wheelbarrow of the Han period (206 BCE–221 CE) appears in short-distance urban transport. The vehicle has a small solid or spoked wheel that is mounted under the front third of the frame, which raises over the wheel. With the center of gravity set low, little above the wheel’s axle, the tilt angle of the barrow was relatively high, reducing the weight that the barrowman had to lift while pushing. Wheelbarrows of this construction remained in use throughout the plains and lowlands of Shaanxi in the northwest across Sichuan and Hunan into Southern China (Figs. 1, 2, and 3). From the eleventh century, a one-wheeled vehicle of a different construction appears in written and pictorial sources of Eastern China. This wheelbarrow had a large spoked wheel of the size of a cartwheel, probably not much less than 1m in diameter. Awooden frame was built over the top half of the wheel with platforms for the load on both sides. The outside beams of these frames extend into two handlebars for the barrowman to work the vehicle and for attaching a sling that ran over his shoulders to take the weight off his arms. The load was usually divided into two and evenly distributed on the two platforms, though bulky goods could be strapped over the top of the housing (Fig. 4). The constructional difference from the ordinary wheelbarrow is the position of the wheel under the load. The barrowman had to balance and push the vehicle, but he no longer needed to lift part of the weight of the barrow and the load. The housed wheelbarrow constituted a gain in efficiency in carrying capacity and range. The large wheel brought reduced friction and better stability compared to the ordinary wheelbarrow, and the balanced load enabled barrowmen to work full days, making the vehicle widely employed in long-distance transport (Fig. 5). The technical difficulty with wheelbarrows is the wheel. In two-wheeled vehicles the wheels are subjected to torque, mainly in turns and to a lesser degree on uneven ground. In a wheelbarrow, by contrast, the wheel has to withstand considerable torque almost permanently, the impact being reduced only when the barrow runs smoothly and with good balance. The technical challenge was met by using either small and simple wheels, usually a solid disk, or alternatively by particularly strong spoked wheels. Andre Wegener Sleeswyk argued that the early development of highly stable yet light spoked wheels in China, which was certainly in place by the Han period, was instrumental in the development of the housed wheelbarrow (Wegener Sleeswyk, 1982). For this reason, a transition from the ordinary to the housed wheelbarrow appears unlikely, as it would involve

CFD simulations of spoked wheel aerodynamics in cycling: Impact of computational parameters

Aerodynamic drag is the main resistive force in cycling at high speeds and on flat terrain. In wind tunnel tests or computational fluid dynamics simulations, the aerodynamic drag of cycling wheels is often investigated isolated from the rest of the bicycle, and sometimes in static rather than rotating conditions. It is not yet clear how these testing and simulating conditions influence the wheel aerodynamic performance and how the inclusion of wheel rotation influences the overall measured or computed cyclist drag. This study presents computational fluid dynamics simulations, validated with wind tunnel tests, that indicate that an isolated static spoked front wheel has a 2.2% larger drag area than the same wheel when rotating, and that a non-isolated static spoked front wheel has a 7.1% larger drag area than its rotating counterpart. However, rotating wheels are also subjected to the rotational moment, which increases the total power required to rotate and translate the wheel compared to static conditions where only translation is considered. The interaction with the bicycle frame and forks lowers the drag area of the front wheel by 8.8% for static and by 12.9% for the rotating condition, compared to the drag area of the isolated wheels. A different flow behavior is also found for static versus rotating wheels: large low-pressure regions develop from the hub for rotating wheels, together with a lower streamwise velocity region inside the circumference of the wheel compared to static wheels. The results are intended to help in the selection of testing/simulating methodologies for cycling spoked wheels.

In a convergent modular synthesis, a very efficient pathway to shape-persistent molecular spoked wheels has been developed and applied according to the covalent-template concept. The structurally defined two-dimensional (2D) oligo(phenylene-ethynylene-butadiynylene)s (OPEBs) presented here are about 8 nm sized hydrocarbons of high symmetry. 48 alkyl chains attached to the molecular plane (hexyl and hexadecyl, respectively) guarantee a high solubility of the compounds. The structure and uniformity of these defined, stable, D(6h) symmetrical compounds is verified by MALDI-MS, GPC analysis, and high-temperature (HT) (1)H and (13)C NMR. Detailed photophysical measurements of nonaggregated molecules in solution (as confirmed by dynamic light scattering (DLS)) focus on the identification of chromophores by comparison with suitable model compounds. Moreover, time-resolved measurements including fluorescence lifetime and depolarization support the chromophore assignment and reveal the occurrence of intramolecular energy transfer. Scanning tunneling microscope (STM) characterization at the solid/liquid interface demonstrates the efficient self-assembly of the OPEBs into hexagonal 2D crystalline layers with a periodicity determined by both the size of the OPEB backbone and the length of peripheral side chains. Atomic force microscope (AFM) studies show a very different assembly behavior of the two spoked wheel molecules, on both graphite and mica. While the hexyl-substituted wheel can form stacked superstructures, hexadecyl groups prevent any ordering in the film aside from the monolayer directly in contact with the surface.

A shape-persistent polyphenylene with a "spoked wheel" structure was synthesized as a subunit of an unprecedented two-dimensional polyphenylene that we name graphenylene. The synthesis was carried out through a sixfold intramolecular Yamamoto coupling of a dodecabromo-substituted dendritic polyphenylene precursor, which had a central hexaphenylbenzene unit as a template. Characterizations by NMR spectroscopy and matrix-assisted laser ionization time-of-flight mass spectrometry provided an unambiguous structural proof for the wheel-like molecule with a molar mass of 3815.4 g/mol. Remarkably, scanning tunneling microscopy visualization clearly revealed the defined spoked wheel structure of the molecule with six internal pores.

Theoretical and experimental studies on the stress in a spoked wheel produced by a horizontal load have been made in the second and third reports. In succesion to these studies, the writers made a theoretical study on the stress produced by a vertical load in a spoked wheel. Pippard-Baker and Kreissig studied this problem already, but their reports are not complete and we cannot find how much load acts on the each spoke, that is, the strength of spoked wheels under veritical load has never been made clear yet. From this point of view, in this report they introduced theoretical equations for the stresses produced by vertical load in each part of the spoked wheels, In these equations, the tire and the rim are treated as rings. That is to say that the tire is a ring on which a load acts from outside and the rim is also a ring on which the reaction force acts through the spokes from inside. and the spokes are treated as the beams on which the tensile force, the bending moment and the shearing force act at the boss and their rim-side roots. Numerical examples for the wheels of railway rolling-stock under vertical load will be shown also in this report.

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. Grayscale ultrasound (US) is the main method used to diagnose benign and malignant thyroid nodules, While color doppler blood flow imaging(CDFI) is not widely recognized when diagnosing thyroid cancer. This study used a retrospective analysis. The study included 36 spoked wheel blood flow nodules detected by CDFI in 37,372 patients in five hospitals from January 2020 to June 2021. All thyroid nodules were examined histologically after ultrasound-guided fine needle biopsy or following surgical resection. The value of color doppler in diagnosing papillary thyroid carcinoma was evaluated based on pathological results. Among 36 thyroid nodules, only 6 were highly suspected of being malignant on grayscale ultrasound (classified as 5, according to ACR TI-RADS). However, these 36 thyroid nodules showed spoke wheel blood flow signal distribution on CDFI. If the spoke wheel blood flow signal is used to diagnose papillary thyroid cancer, then the diagnostic accuracy of this group of papillary thyroid cancers can reach 100%, which is significantly higher than the accuracy of grayscale ultrasound diagnosis, and the difference is statistically significant (p<0.05). The results of this study found that spoke wheel blood flow sign on CDFI can be used to diagnose PTC. PTC with spoke wheel blood flow have benign characteristics on gray-scale ultrasound, which is easy to be misdiagnosed.

The physiological, subjective and biomechanical effects of altering flywheel weight and pedalling rate on a Quinton Model 870 bicycle ergometer were studied. Steel plates were added to the flywheel to increase its weight to 35·9 kg with a moment of inertia of 1·65 kg m2. A 1·5 kg spoked wheel with a moment of inertia of 0·1 kg m2 was used as the light flywheel. Eight subjects pedalled on two separate occasions for 6 min at 40, 50, 60, 70, 80 and 90 r.p.m. with workload levels representing 30 and 60% of their [Vdot]O2max with each flywheel. Force plate pedals were used to measure the total resultant force on the pedals (FR ) and the component perpendicular to the crank arm (FT). A force effectiveness index (FEI) was denned as the average of FT/FR over a crank cycle. The result showed no statistically significant change (p<0·05) in [Vdot]O2, heart rate and rating of perceived exertion of the FEI as a function of flywheel weight except for the [Vdot]O2 at 50 r.p.m. for the light workload. As the r.p.m. incre...

CFD simulations of an isolated cycling spoked wheel: The impact of wheel/ground contact modeling in crosswind conditions

An approach to multicomponent coordination-driven self-assembly of the first terpyridine-based, shape-persistent, giant two-dimensional D(6h) supramacromolecular spoked wheel is reported. Mixing core T6, rim T3, and Zn(II) or Cd(II) ions in a stoichiometric ratio (1:6:12) permitted the selective generation of a highly symmetric spoked wheel in 94% isolated yield via geometric and thermodynamic control. The products were characterized by a combination of traveling-wave ion mobility mass spectrometry and NMR techniques together with TEM imaging, which agreed with computational simulations.

The double‐ or triple‐decker 3D metallo‐hexagons were obtained by self‐assembly of multitopic tris‐terpyridines with Cd2+ ions in near‐quantitative yield. Comprising up to 72 ionic pairs, the multiple spoked wheels display characteristic reversible gelation properties under thermodynamic conditions. The supramolecular metallo‐nanoarchitectures were characterized by 1H NMR, 2D NMR (COSY and NOESY), and diffusion‐ordered spectroscopy (DOSY) and HR‐ESI‐MS, traveling‐wave ion mobility mass spectrometry (TWIM‐MS), TEM, and AFM. For the first time, the self‐assembly of 45 units at once was demonstrated to yield exceptional giant triple‐decker hexagons of up to circa 42 000 Da.