Predetermined Axis Research Articles

Vacuum End Effector Equipped with an Expansion and Contraction Mechanism Using a Wound Thin Metal Plate

We propose a vacuum end effector with an expansion and contraction mechanism to realize a picking task for objects placed in a narrow space, such as a shelf. The proposed expansion and contraction mechanism consists of a tube and exoskeleton structure and is characterized by the use of a thin metal plate wound about itself to form a tubular exoskeleton. Expansion and contraction motions were realized by connecting the tube to a linear motion mechanism. The expansion and contraction mechanism can be easily extended by elastic force. In addition, the shape of the expansion and contraction mechanism is created by winding a thin metal plate around a predetermined axis, which ensures high rigidity even in the extended state. Even when an object to be picked from a shelf is located behind other objects, the end effector can efficiently hold the object because of its elongated shape and ability to freely change the position of the suction pad using a direction-changing linkage and the expansion and contraction mechanism. The developed end effector weighs about 1.46 kg and can carry a load of 0.56 kg when extended to 150 mm. Verification of the mechanism confirmed that the developed end effector is useful because it can perform the expected object-picking operation.

The energy distribution of subjets and the jet shape

We present a framework that describes the energy distribution of subjets of radius r within a jet of radius R. We consider both an inclusive sample of subjets as well as subjets centered around a predetermined axis, from which the jet shape can be obtained. For r ≪ R we factorize the physics at angular scales r and R to resum the logarithms of r/R. For central subjets, we consider both the standard jet axis and the winner-take-all axis, which involve double and single logarithms of r/R, respectively. All relevant one-loop matching coefficients are given, and an inconsistency in some previous results for cone jets is resolved. Our results for the standard jet shape differ from previous calculations at next-to-leading logarithmic order, because we account for the recoil of the standard jet axis due to soft radiation. Numerical results are presented for an inclusive subjet sample for pp → jet + X at next-to-leading order plus leading logarithmic order.

Tissue-Autonomous Promotion of Palisade Cell Development by Phototropin 2 inArabidopsis

Light is an important environmental information source that plants use to modify their growth and development. Palisade parenchyma cells in leaves develop cylindrical shapes in response to blue light; however, the photosensory mechanism for this response has not been elucidated. In this study, we analyzed the palisade cell response in phototropin-deficient mutants. First, we found that two different light-sensing mechanisms contributed to the response in different proportions depending on the light intensity. One response observed under lower intensities of blue light was mediated exclusively by a blue light photoreceptor, phototropin 2 (PHOT2). Another response was elicited under higher intensities of light in a phototropin-independent manner. To determine the tissue in which PHOT2 perceives the light stimulus to regulate the response, green fluorescent protein (GFP)-tagged PHOT2 (P2G) was expressed under the control of tissue-specific promoters in the phot1 phot2 mutant background. The results revealed that the expression of P2G in the mesophyll, but not in the epidermis, promoted palisade cell development. Furthermore, a constitutively active C-terminal kinase fragment of PHOT2 fused to GFP (P2CG) promoted the development of cylindrical palisade cells in the proper direction without the directional cue provided by light. Hence, in response to blue light, PHOT2 promotes the development of cylindrical palisade cells along a predetermined axis in a tissue-autonomous manner.

Three-Dimensional Transesophageal Echocardiography Is a Major Advance for Intraoperative Clinical Management of Patients Undergoing Cardiac Surgery

Echocardiography is a key assessment tool for the evaluation of cardiac structure and function. The ability to image cardiac structures using 3-dimensional (3D) echocardiography is evolving. In this article, we present some of the key features of the emerging 3D technology and review its applications with an emphasis on real-time 3D transesophageal echocardiography.

Accuracy of a predetermined transverse horizontal mandibular axis point

Statement of Problem. The transverse horizontal mandibular axis point may be located most precisely by a kinematic process. However, an anatomical method of locating the axis is also an acceptable technique, and an easily determined point that is consistently close to the kinematic axis would simplify transfer of the arc of rotation from the patient to the articulator. Purpose. This in vivo study compared the location of an anatomically predetermined hinge axis point with the determined kinematic axis. Material and Methods. Forty subjects (27 males, 13 females; 23 to 47 years of age) with functionally acceptable occlusion and no detectable clinical signs of temporomandibular disorders participated in the study. The earpiece alignment flags on a mechanical SAM Axiograph III combination flag/face-bow were used to locate the right and left predetermined hinge axis points, 10 mm anterior to the earpiece. The right and left kinematic center of rotation was located as described by Lauritzen and confirmed with the PC Axiotron electronic Axiograph to within 0.25 mm. All points were transferred to 1 mm2 grid paper on the subject's skin. The distance between each predetermined and kinematic point was measured ±0.25 mm. Wilcoxon and Mann-Whitney tests were used to examine differences between the left and right axis points and potential significant differences between genders at a significance level of P<.05. The number of occurrences and the distance of the predetermined axis points from the kinematic axis also were described. Results. The mean distance between points was 1.1 mm on the right (range 0.0 to 3.0 mm), 1.2 mm on the left (range 0.0 to 3.0 mm), and 1.1 mm for all 80 points (±0.63). More than 96% of the predetermined points were within 2 mm of the kinematic axis, and 67% were within 1 mm. There was no significant difference between the right and left points and no significant differences based on gender. Conclusion. Within the limitations of this study, the results suggest that the predetermined axis point is well within the clinical norm for estimated location of the transverse horizontal mandibular axis. (J Prosthet Dent 2002;87:387-94.)

Practical visualization of rock structure

The conventionally applied method for visualizing the structure of a rock mass is limited to plotting the orientation of individual discontinuities by using the Schmidt stereographic net. Their spacing is not illustrated and other structural features, such as undulation and twisting, cannot be interpreted from such sterographic views. A new mode of visual presentation of rock structural features of one or several different types in rock volumes of any size that makes all this possible is proposed in the present report. The primary purpose is to quantify, for all elements of a rock mass where the structure has been evaluated by borehole investigations or mapping in the course of underground excavation, the orientation and average spacing of defined discontinuities like hydraulically and mechanically active fractures. These local structural patterns, which are plotted on three of the six faces of cubical boxes with defined edge length and with one edge oriented N−S can be combined by applying the mathematical tool for connecting faces with which certain visualization codes like Alias Sketch are equipped. This combines different local rock structures to form regional patterns that can reveal undulation and twisting and important variations in spacing of major discrete discontinuities. Visualization can be given in true perspective or orthographic form and larger discontinuities that have been identified in the field, such as fracture zones, can be introduced in the model for correlation with smaller features. Furthermore, the stress situation at all sites where rock stress measurements have been made can be visualized in the model in the form of principal planes. The proposed models can be visualized from any “camera angle” and also shown in Quick Time VR form, i.e. as being slowly rotated around any predetermined axis. This facilitates definition and selection of the rock structure, local or regional, for numerical calculations.

Vibration test bearing table apparatus affording a single degree of freedom test piece path

First Page

A precision goniometer stage for the electron microscope

A goniometer stage of entirely new design has been built for the electron microscope. It has a number of features not hitherto applied to the construction of goniometer stages which make it particularly valuable in quantitative work. In the Siemens Elmiskop I microscope, the goniometer stage permits a tilt of ±12½° about any predetermined axis, whilst still retaining the full traverse of ±0.8 mm. The axis of tilting and the magnitude of the rotation may be set precisely without recourse to calculation. The stage also allows any number of accurate tilting operations to be employed consecutively without calculation, provided the vector sum of the tilts does not exceed 12½°. It is possible to extend the maximum angle of tilting, but the semi-immersion objective pole piece of the Elmiskop I and the type of translation movement used limit the maximum tilt to about ±20°. The area of the bearing surfaces employed is not restricted by the size of the pole piece. This allows large surfaces to be used giving a robust, precise instrument which will retain its accuracy and smoothness of motion for long periods.