The first xiphydriid wood wasp in Cretaceous amber (Hymenoptera: Xiphydriidae) and a potential association with Cycadales

A new genus and species of fossil wood wasp is described and figured from mid-Cretaceous Kachin amber, representing the first occurrence of the family Xiphydriidae in the fossil record. Paraxiphydria resinata gen. et sp. nov. exhibits typical apomorphies of the family including a generally cylindrical body, elongate neck and dome-shaped head. Nonetheless, owing to a unique combination of traits including features hitherto unknown among species of the family, the genus is classified within a separate subfamily, Paraxiphydriinae subfam. nov. A key is presented to the suprageneric groups of Xiphydriidae. The newly described species is the first fossil xiphydriid wood wasp, extends the occurrence of Xiphydriidae into the mid-Cretaceous and adds to the known diversity of features in the family. Lastly, the simplification of wing venation and hypotheses of host-plant affiliations of early xiphydriids are discussed. We evaluate pollen associated with the wasp, assign it to the genus Cycadopites and conclude that an affiliation to the Cycadales is most likely. Article and nomenclatural acts are registered in ZooBank (http://zoobank.org/, last access: 15 December 2021), with the following life science identifier (LSID) (reference): urn:lsid:zoobank.org:pub:DA80920E-E94B-4A8E-A817-077FA7BD7D69.

Improving the efficiency of carousel wind turbine using aerodynamic shield

The problem of increasing the efficiency of using the oncoming air flow for a wind wheel with a vertical axis of rotation, which is a mechanical drive of the wind heat generator, is considered. It is proposed to increase the efficiency of the device by installing an aerodynamic shield for the air flow oncoming the wind wheel. Such a shield is a cylindrical body in which a heat generator is placed. The shield creates an effect of confuser, leading to an increase in the speed and, consequently, in the kinetic energy of the air flow acting on the rotor blades. It is shown experimentally that the presence of an aerodynamic shield under the conditions of the experiments carried out at an incoming air flow velocity of ~ 1 m/s leads to a practical doubling of the wind wheel torque.

Theoretical Study and Analysis of a Device for Pickling and Moving Bulk Materials

Theoretical studies of the operation of a device for pickling and moving bulk materials are discussed. A particular analysis of the Lagrange equation for the motion of a particle in a spiral-helical device is described. The images are presented with all forces and velocity vectors acting on a particle from the side of the spiral screw and the inner surface of the device body during its movement. The expression for the angle θ, which characterizes the geometric parameters of the spiral and cylindrical body, as well as the size of the material particles in the device, has been investigated and transformed.

Use of the Symmetries in the Study of Vibration Response of a Hollow Cylinder

The paper studies the vibration response of an elastic solid that has geometric symmetries. These determine special properties of the equations of motion of such a system, presented in the case of a cylindrical body (hollow cylinder). The properties of the eigenvalues and eigenmodes of these systems are theoretically established. A validation of these results is made using the finite element method. The use of the obtained results can lead to an easing of the vibration analysis of such a system and, consequently, to the decrease of the cost related to the design and manufacture of such a structure. The properties presented and demonstrated in the paper can simplify the numerical calculation and experimental verifications of such a structure. Serving these symmetries, the computation cost decrease substantially and will depend not in the number of the identical parts.

IDENTIFIKASI DAN PREVALENSI ENDOPARASIT (Gnathostoma sp.) PADA BELUT SAWAH (Monopterus albus) DENGAN UKURAN BERBEDA YANG DIKIRIM KELUAR PROVINSI KALIMANTAN SELATAN

This study aims to determine the type of endoparasitic worm Gnathostoma sp and the prevalence that infects rice field eel (Monopterus albus) with different grades. the method used is the descriptive method. Samples were taken from 3 different farm locations (Nor Aini, Banjar Regency, CV. Karya Bersama, Banjarbaru City, and Saberiannor Banjarbaru City), as many as 120 individuals with each grade (A, B, C, and D) totaling 30 individuals. Samples were examined using the microscopic method with 3 replications on each target organ, namely liver, meat, intestines, and kidneys. The results of the examination showed that Gnathostoma sp worm cysts were found, namely only in the liver, while in the intestines, flesh, and kidneys were not found. Based on the identification of Gnathostoma sp endoparasites seen from morphological characteristics, third-stage larvae (L3) in the phylum Nematoda, cylindrical body shape, transparent body color, and blackish brown, head shape resembling a light bulb, mouth, and has anus at the end of its body. Prevalence value in grade A = 40%; B= 30%; C= 40%, and D= 30%, this includes the category commonly or ordinary which describes that the parasite usually infects fish with a prevalence value range of 30-49%. It is still possible to send rice field eels outside of South Kalimantan Province, although the results of the examination of the test samples indicated the presence of the parasite infection Gnathostoma sp..

Theoretical Hydrodynamic Analysis of a Surface-Piercing Porous Cylindrical Body

In the present study, the diffraction and the radiation problems of water waves by a surface-piercing porous cylindrical body are considered. The idea conceived is based on the capability of porous structures to dissipate the wave energy and to minimize the environmental impact, developing wave attenuation and protection. In the context of linear wave theory, a three-dimensional solution based on the eigenfunction expansion method is developed for the determination of the velocity potential of the flow field around the cylindrical body. Numerical results are presented and discussed concerning the wave elevation and the hydrodynamic forces on the examined body for various values of porosity coefficients. The results revealed that porosity plays a key role in reducing/controlling the wave loads on the structure and the wave run-up, hence porous barriers can be set up to protect a marine structure against wave attack.

Evaluation of the Bonding Strength between Various Dental Zirconia Models and Human Teeth for Dental Posts through In Vitro Aging Tests

In dentistry, root canal treatment reduces support of the tooth, making it necessary to insert a cylindrical body into the treated tooth to strengthen the crown. In the past, metal or fiberglass was often used. However, metal is too different in color from teeth, so the esthetics are poor, and fiberglass is not as strong as metal. Therefore, an alternative is zirconia, which has the characteristics of high light transmittance, esthetics, good biocompatibility, and high breaking strength. The surface morphology and composition of zirconia ceramics are the key to their bond strength with teeth. Therefore, in this study, the surface characteristics of different brands of zirconia commonly used in clinical practice were evaluated in terms of their surface morphology and surface elements. The surface was modified by sandblasting, and its effect on the bonding strength was discussed. Finally, the stability of the material was evaluated through artificial aging. The results showed that the surface roughness of the zirconia specimens increased after sandblasting, whereas the surface microhardness decreased. The shear test results showed that the 3D shape of the zirconia surface could help improve the bonding strength. The bonding strength of DeguDent increased the most after sandblasting. After 20,000 cycles of aging treatment, the shear strength of each specimen decreased. Field emission scanning electron microscopy results showed that the adhesive remained intact on the surface of zirconia, indicating that adhesion failure occurred between the adhesive and the teeth. This confirms that sandblasting can improve the bonding strength of zirconia. Based on the results obtained, it was concluded that the surface roughness of zirconia is the main factor affecting the bond strength.

Interaction of Viscoelastic Tube with Inner Nonuniform Coating of Variable Thickness and Rigid Cylindrical Insert

This work is devoted to the formulation and search of an analytical solution for the problem of the interaction of a rigid cylindrical body and a pipe with an inner coating in the case when the cylinder is placed inside such a pipe. It is assumed that the pipe coating can have a strong nonuniformity, and its thickness depends on the longitudinal coordinate. A special approach used in this work allows obtaining analytical solutions in which functions related to the properties and profile of the coating are separated by separate terms and factors. This allows us to provide efficient calculations even in cases where coating characteristics are described by complex functions. Other known methods lead to significant calculation errors.