Slender Shaft Research Articles

The Reserch on PID Control Modle of the Components Working Accuracy for Slender Shaft on the NC Lathe

In this article, a PID control modle of working accuracy is constructed to control the processing process，regarding the closed loop manufacture system as a black box and the processing error as system deviation. A slender shaft with a surface is turned,the control points of the error compensation can be abtained by a probe.Based on the CAM technology，an automatic programming system is developmented to control the processing process.Through a set of comparative experiments,the detaction and the analysis of datas confirmed the validity of the PID control modle,validated the accuracy of the slender shaft can be improved by the PID control modle.

The Research on Turning Operation of Varied Diameter Slender Shaft

By analysing the processing characteristics of varied diameter slender shaft parts, and according to the basic vibration theory of slender shaft, a production machine is designed,moreover, a solution with flexible hydraulic follower rest and elastic tailstock is adopted creatively. Experimental results show that this machine tools can effectively improve radial dimensional accuracy,surface quality and production efficiency of the varied diameter slender shaft parts and it has a wide range of engineering significance.

Research on Accuracy of Abrasive Belt Grinding

The experiment on slender shaft open-cycle belt grinding process is conducted in this paper. The research objects are dimensional accuracy and deviation from roundness error, the changes of which are emphasized after the belt grinding. And the factors affecting the working accuracy of the belt grinding are analyzed. Some measures for improving working accuracy of the belt grinding are put forward. Research result shows that by installing a belt grinding device on a lathe to grind the slender shafts can improve the accuracy with high efficiency.

Mechanical Analysis of Machining Error in Turning Slender Shafts by Reversible Turning Technique

Mechanical analysis is carried out to the deformation of workpiece when turning slender shafts in the normal and reversed direction under two different conditions of clamping. Mathematical models are set up for the calculation of bending deformation resulting from cutting force in condition of normal and reversed turning. An example is given to show that bending deformation and the resulting machining error in conditions of reversed turning is much less than that in normal turning. The result has been verified by experiments. The mechanical model and numerical analysis can be used in the processing design of slender shaft turning.

Surface Roughness Estimation in Grinding by Using Multi-Sensor Data Fusion

Due to the difficulty of real-time directly measuring the surface roughness of workpiece, on-line control of grinding quality remains a challenging problem. In this paper, surface roughness of slender shaft during grinding is predicted by using multi-sensor data fusion. Location of the grinding point along the workpiece axis is measured by a grating ruler while an eddy sensor mounted on the machined body provides the workpiece vibration information. The data from these sensors fuse to give an estimation of the workpiece surface roughness. Grinding experiments were carried out to validate this method and the results indicate that the prediction error of Ra is not over 0.1 um for the given setup.

A new leafhopper genus and four new species from the Grassland Biome of South Africa (Hemiptera, Cicadellidae)

A new endemic deltocephaline leafhopper, Tetramelasma gen.n. is described from the Grassland Biome of South Africa, comprising four new species: T. litopyx sp. n., T. nodosatha sp. n., T. scolosatha sp. n. and T. tanyphysis sp. n. Two paired dark markings on the vertex of the head are striking features of this genus and it is found in association with a number of grass species usually at high altitudes in the Grassland Biome. Species of this genus are characterized in the male by a short, truncated plate with a dorsal sclerotized process, the aedeagus with a long, slender shaft that is fused with the connective. Tribal placement in Deltocephalini is based on the fusion between the aedeagus and connective. The style has the posterior apophysis short and hollow or elongate and somewhat serrated. Females are characterized by the sternite 7 that is deeply invaginated along the posterior margin or only with a shallow notch, semicircular and sclerotized laterally.

Dynamic Analysis of Slender Shaft in Twin-Spindle Turning

Machining slender workpiece is still a technical difficulty. This paper investigates the dynamic behavior of a slender shaft subject to constant feedrate moving cutting forces in twin-spindle turning process. The Euler-Bernoulli theory is used to model the rotating shaft. A dynamic cutting force model is formulated considering the flexibility of workpiece and rigid machine tool. The modal analysis method is employed to solve the dynamic response of the shaft. The parametric influence to the response and natural frequencies of shaft is discussed. Finally, the results are presented and compared between constant cutting forces and deflection-dependent force model introduced in this paper. It is found that there exists a stiffening effect due to the cutting process.

Laparoscopy-Assisted Distal Gastrectomy with Jejunal Pouch Interposition

The incidence of early gastric cancer (EGC) has been increasing in Asian countries as a result of the development of diagnostic modalities such as endoscopic examination and barium meal examination. Currently in Japan, patients with EGC account for more than half of all patients with gastric cancer. More than 90% of patients with EGC can be cured only by curative gastrectomy. Therefore, in the treatment of EGC, not only complete removal of cancer cells but also minimal invasiveness and improvement of patient quality of life (QOL) after surgery are essential. Distal gastrectomy (DG) with Billroth-I (B–I) reconstruction is the most popular surgical treatment for distal EGC in Japan. Recently, this operation has begun to be performed minimally invasively with laparoscopy-assisted techniques. However, many patients who have undergone open DG or laparoscopy-assisted DG (LADG) have experienced postgastrectomy syndrome, which involves efflux esophagitis, dumping syndrome, and loss of appetite. To prevent postgastrectomy syndrome after DG or LADG, several modified gastrectomy techniques have been developed: pylorus-preserving gastrectomy (PPG), vagal nerve-conserving gastrectomy, and gastrectomy with jejunal pouch interposition (JPI), among others. In this issue of the Annals, Junhyun et al. report the technical safety of LADG with JPI and the better long-term QOL experienced by patients undergoing this operation. The techniques of LADG with JPI, and especially the procedure for forming the jejunal pouch, are more complex than LADG with B–I reconstruction. In this procedure, creation of the jejunal pouch is performed under minilaparotomy in a manner similar to that under open surgery. Although autosuturing machines are used to simplify the techniques of jejunal pouch creation, there are several technical risks including ischemic change of the pouch, bleeding from the sutured edge, and ischemic change at the site of the pouch-duodenal anastomosis. To overcome these problems, several improved techniques have been devised: jejunal J-shaped pouch, short-length jejunal pouch, and use of a surgical stapler with a long slender shaft and three rows of staples (white cartridge). The study by Junhyun et al. evaluated the outcomes of LADG with a 10-cm Ushaped pouch made with a linear stapler with two rows of staples. Although the incidence of postoperative complications was not high, 2 of 25 patients had intra-abdominal bleeding. Thus, it is necessary to establish safe techniques for the performance of LADG with JPI. LADG with JPI was developed to provide patients with EGC advantages such as early recovery after surgery and improvement in postoperative QOL. In their article, Junhyun et al. report good QOL in patients who underwent LADG with JPI compared with those who underwent Billroth-II (B-II) reconstruction. Few reports address postoperative QOL after DG with JPI because of several problems related to research on patient QOL after gastrectomy. First, most important is determining what kind of postDG reconstruction method should be used as a control in the study of patient QOL. Patient QOL after gastrectomy primarily depends on the reconstruction method. Theoretically, dietary volume, systems to prevent efflux, and speed of digestion and movement of food into the duodenum may affect patient QOL. The aims of JPI are to increase dietary volume and decrease the symptoms of efflux. Junhyun et al. compared postoperative QOL after JPI reconstruction with that after B-II reconstruction. Although B-II reconstruction is the most popular method used in China and Korea, a comparison study between LADG with and without JPI should be performed to clarify the effect of JIP on postoperative QOL. A number of reconstruction Society of Surgical Oncology 2010

Error Compensation in Turning Operation of Slender Shaft Using a Fuzzy PID Controller

Turning operation of slender shaft poses a great challenge in machining field. It is due to the fact that the accuracy of machined workpiece depends almost completely on the operator’s skill by using conventional methods. To improve the accuracy of slender shaft with less operation skill, this paper presents an error compensation system, which includes a fuzzy PID controller. As a part of the controller, the traditional PID controller is used to control a follower rest for improving the dimensional accuracy. And the fuzzy controller incorporates skilled operators’ knowledge into an automatic machining system. At the end, turning experiments are carried out to verify the efficacy of the error compensation system. The experimental results indicate that the dimensional accuracy of slender shaft using the system is higher and more stable than that by using conventional methods.

The computation of torsional, dynamic stresses

The torsional dynamics of spatially dispersed, mechanical, power transmission system models are considered. Distributed—lumped parameter modelling methods are employed in the analysis of configurations comprising rotors, bearings, and relatively slender shaft arrangements. Analysis procedures enabling the computation of the torsional shear stress and velocity response of these drive systems are outlined and block diagram representations are formulated. The transient characteristics for shaft—rotor arrangements following deterministic input changes are computed. Typical rotor—shaft assemblies are investigated, illustrating thereby the procedures involved. Graphical results and comparative studies are presented and the generality of the techniques detailed is commented upon.

THE SKELETAL ANATOMY AND RELATIONSHIPS OF A NEW DISCOSAURISCID SEYMOURIAMORPH FROM THE LOWER PERMIAN OF MORAVIA (CZECH REPUBLIC)

A new genus and species of seymouriamorph tetrapod from the Lower Permian deposits of the Boskovice Furrow in Moravia (Czech Republic), Spinarerpeton brevicephalum, new genus, new species, is described in detail, and its cranial reconstruction and phylogenetic position within seymouriamorphs is presented. The skeletal anatomy of Spinarerpeton allows this new taxon to be assigned to the family Discosauriscidae (together with Discosauriscus Kuhn, 1933, Makowskia Klembara, 2005, and Ariekanerpeton Ivakhnenko, 1981). It is distinguished from other ?Uppermost Carboniferous-Lower Permian seymouriamorphs, Utegenia Kuznetsov and Ivachnenko, 1981, Ariekanerpeton, Discosauriscus, Makowskia, and Seymouria Broili, 1904, by the following characters: postorbital portion of skull short; postparietal and tabular abbreviated anteroposteriorly; posterior process of jugal long; squamosal high (posterior portion of cheek deep); basioccipital wide and with anteroposteriorly long bilateral processes; exoccipital high and with slender shaft; anterior margin of iliac blade running obliquely anteroventrally to posterodorsally. A phylogenetic analysis places Spinarerpeton as the sister taxon to the Lower Permian Makowskia within the Discosauriscidae.

Crack detection in a shaft by combination of wavelet-based elements and genetic algorithm

A new crack detection method is proposed for detecting crack location and depth in a shaft. Rotating Rayleigh-Euler and Rayleigh-Timoshenko beam elements of B-spline wavelet on the interval (BSWI) are constructed to discretize slender shaft and stiffness disc, respectively. According to linear fracture mechanics theory, the localized additional flexibility in crack vicinity can be represented by a lumped parameter element. The cracked shaft is modeled by wavelet-based elements to gain precise frequencies. The first three measured frequencies are used in crack detection process and the normalized crack location and depth are detected by means of genetic algorithm. To investigate the robustness and accuracy of the proposed method, some numerical examples and experimental cases of cracked shaft are conducted. It is found that the method is capable of detecting crack in a shaft.

Structure of the C-terminal head domain of the fowl adenovirus type 1 long fiber

Avian adenovirus CELO (chicken embryo lethal orphan virus, fowl adenovirus type 1) incorporates two different homotrimeric fiber proteins extending from the same penton base: a long fiber (designated fiber 1) and a short fiber (designated fiber 2). The short fibers extend straight outwards from the viral vertices, whilst the long fibers emerge at an angle. In contrast to the short fiber, which binds an unknown avian receptor and has been shown to be essential to the invasiveness of this virus, the long fiber appears to be unnecessary for infection in birds. Both fibers contain a short N-terminal virus-binding peptide, a slender shaft domain and a globular C-terminal head domain; the head domain, by analogy with human adenoviruses, is likely to be involved mainly in receptor binding. This study reports the high-resolution crystal structure of the head domain of the long fiber, solved using single isomorphous replacement (using anomalous signal) and refined against data at 1.6 A (0.16 nm) resolution. The C-terminal globular head domain had an anti-parallel beta-sandwich fold formed by two four-stranded beta-sheets with the same overall topology as human adenovirus fiber heads. The presence in the sequence of characteristic repeats N-terminal to the head domain suggests that the shaft domain contains a triple beta-spiral structure. Implications of the structure for the function and stability of the avian adenovirus long fiber protein are discussed; notably, the structure suggests a different mode of binding to the coxsackievirus and adenovirus receptor from that proposed for the human adenovirus fiber heads.

Identification of crack in a rotor system based on wavelet finite element method

The dynamics and diagnosis of cracked rotor have been gaining importance in recent years. In the present study a model-based crack identification method is proposed for estimating crack location and size in shafts. The rotor system has been modeled using finite element method of B-spline wavelet on the interval (FEM BSWI), while the crack is considered through local stiffness change. Based on Rayleigh beam theory, the influences of rotatory inertia on the flexural vibrations of the rotor system are examined to construct BSWI Rayleigh beam element. The slender shaft and stiffness disc are modeled by BSWI Rayleigh–Euler beam element and BSWI Rayleigh–Timoshenko beam element, respectively. Then the crack identification forward and inverse problems are solved by using surface-fitting technique and contour-plotting method. The experimental examples are given to verify the validity of the BSWI beam element for crack identification in a rotor system. From experimental results, the new method can be applied to prognosis and quantitative diagnosis of crack in a rotor system.

A Silurian ‘marrellomorph’ arthropod

Xylokorys chledophilia, a new arthropod with three-dimensionally preserved soft tissues, is described from the Herefordshire (Silurian) Lagerstätte of England. The head and trunk are covered by a relatively featureless ovoid carapace, which comprises a domed central part and a flange-like border. The head bears five pairs of appendages. The first is uniramous, with dorsal and ventral projections distally. Appendages two to four are biramous and each endopod terminates in two projections. Appendage five is possibly biramous. The hypostome is very long and subrectangular in outline. There are approximately 35 pairs of biramous trunk appendages. Each exopod comprises a long slender shaft bearing numerous fine filaments; each endopod comprises a ribbon-like shaft bearing paddle-like endites. Morphological comparisons and cladistic analyses of X. chledophilia indicate affinity with Vachonisia rogeri from the Lower Devonian Hunsrück Slate, within the marrellomorphs, but assignment to Marrellomorpha is provisional pending revision of other members of this clade. Xylokorys is the first 'marrellomorph' to be reported from the Silurian. It is interpreted as a benthic particle filter feeder, which may also have consumed prey items.

The process analysis and improvement of the slender and flat shaft of track recorder

A slender and flat shaft is a key part of the track recorder in marine vessels. However, the axial straightness of the shaft often exceeds standard measurements after it is machined. It has also been found that its precision does not last a long time. After thorough analysis of these problems the main reasons that affect machining quality are identified-and a process modification plan is put forward that meets design requirements of the shaft. The production and practice indicate that the precision of the shaft is stable for a long period and the quality of products improved substantially after new measures were employed, securing the e accuracy of the track recording of the marine vessel.

Simulating the Diameter Error Due to the Dynamic Response of a Spinning Slender Shaft in Turning Operation

Slender bar is widely applied in practice, but its turning operation is much more difficult than that of ordinary workpiece.The major problem lies in the fact that the high transversal deflection of workpiece results in high diameter error in turning slender shaft. In order to investigate the development of diameter error, the turning operation is simulated by using the Rayleigh beam theory. Through this theory, the dynamic response of a rotating workpiece under the cutting force is determined. Then, the diameter error of slender bar is determined based on the geometric correlation between the workpiece deflection and the diameter error. In this simulation, the cutting force is obtained using an empirical model, which is extensively used. Finally, a series of experimental tests are carried out to validate the simulation of diameter error. The experimental results demonstrate that the simulated values are considerably accurate. In addition, in order to eliminate the diameter error through error compensation method, the nominal depth of cut corresponding to a certain actual depth is determined by using the proposed model. The originality of this work is that the rotational motion of workpiece is taken into account in determining the diameter error of slender bar.

Structure of the Carboxy-terminal Receptor-binding Domain of Avian Reovirus Fibre SigmaC

Avian reovirus fibre, a homo-trimer of the sigmaC protein, is responsible for primary host cell attachment. The protein expressed in bacteria forms elongated fibres comprised of a carboxy-terminal globular head domain and a slender shaft, and partial proteolysis yielded a carboxy-terminal protease-stable domain that was amenable to crystallisation. Here, we show that this fragment retains receptor-binding capability and report its structure, solved using two-wavelength anomalous diffraction and refined using data collected from three different crystal forms at 2.1 angstroms, 2.35 angstroms and 3.0 angstroms resolution. The carboxy-terminal globular domain has a beta-barrel fold with the same overall topology as the mammalian reovirus fibre (sigma1). However, the monomers of the sigmaC trimer show a more splayed-out arrangement than in the sigma1 structure. Also resolved are two triple beta-spiral repeats of the shaft or stalk domain. The presence in the sequence of heptad repeats amino-terminal to these triple beta-spiral repeats suggests that the unresolved portion of the shaft domain contains a triple alpha-helical coiled-coil structure. Implications for the function and stability of the sigmaC protein are discussed.

Research and Application on High Efficiency Reversible Cutting Technique

Reversible cutting method is a research thesis proposed to shorten processing route, decrease tool number and handling time, increase machining efficiency. There are three movement ways, i.e. reversible feed motion, reversible primary motion and reversible composite motion. Primary motion is done by workpiece, conventional or reversible feed motion is done by cutting tool in the way of reversible feed motion, e.g. turning. Cutting velocity is passed to cutting tool, clockwise or anti-clockwise cutting movement is done by cutting tool in the way of reversible primary motion, e.g. milling, shaping, drilling (spade drill), reaming. Primary and feed motions are all reversible in composite motion, e.g. turn-milling. Chip deformation and machined surface with reversible finishing is discussed. A mechanical analysis is carried out to the workpiece deformation of slender shaft turning in normal direction and reversible direction. The result has been verified by experiments. Experimental data for the range of cutting parameters tested showed that the reversible fine machining produce the compressive residual stresses at the surface, which are critical in the performance of the machined components. Experimental research indicted that the results of micro-hardness of reversible fine machining technique are smaller than that of general fine machining show that decreased plastic deformation of the surface layer and work-hardening. It can be adopted such planning which rough machining during advance stroke and fine machining during return stroke in machining process.

A relict trematosauroid (Amphibia: Temnospondyli) from the Middle Jurassic of the Junggar Basin (NW China).

A temnospondyl ilium from the uppermost Toutunhe Formation (Middle Jurassic, Callovian) of the southern Junggar Basin is described. Among the known temnospondyls it is very unusual in morphology because of its very long and slender shaft. It compares closely only to the ilium of one of the latest known trematosaurids from the Ladinian of southern Germany. The Toutunhe Formation has also yielded vertebrae and skull fragments of temnospondyls which belong to the brachyopid Gobiops from the Upper Jurassic of Mongolia. Brachyopoid ilia do not, however, display a morphology similar to that of the new specimen. It is therefore concluded that this specimen represents a second taxon of temnospondyl from the Toutunhe Formation, which probably represents the latest surviving trematosauroid. The Trematosauroidea, which was hitherto exclusively known from the Lower to early Upper Triassic, therefore joins the Brachyopoidea--and possibly the Capitosauroidea --as another group of temnospondyls which survived the end--Triassic mass extinction.