Double Posts Research Articles

Fracture Resistance of Endodontically Treated Maxillary Premolars with a Longer Single Post and Shorter Double Posts of Different Sizes: An In Vitro Study.

ABSTRACTAim:The aim of this study was to determine if there is any difference in fracture resistance between different post sizes and lengths when more than one post is involved.Materials and Methods:Thirty extracted maxillary first premolars were endodontically treated and divided into three groups: In Group 1 (control group), no post space preparation was conducted and access cavities were restored with composite; in Group 2 (single post), post space preparation of 10 mm was carried out only in one of the canals; and in Group 3 (double post), post space preparation of 5 mm was conducted in both the canals. Appropriately sized glass fiber posts were cemented in Groups 2 and 3 followed by core buildup. The fracture resistance of the specimen was measured using a universal testing machine and the data analyzed. The mean fracture resistance values of the three groups were compared applying one-way analysis of variance (ANOVA) followed by post hoc Tukey’s test. The data were analyzed using Statistical Package for the Social Sciences software program, version 15.0. South Asia, Bangalore.Results:The control group had a significantly lower fracture resistance value as compared to Groups 2 and 3. No statistically significant difference was observed in the fracture resistance between Groups 2 and 3.Conclusions:No significant difference was observed between the fracture resistance of endodontically treated maxillary first premolars restored with size 3 single post of longer length and size 1 double posts of shorter lengths.

DSA-Compliant Routing for 2-D Patterns Using Block Copolymer Lithography

2-D directed self-assembly (DSA) is an emerging lithography for the 5-nm process node and beyond that can substantially increase design flexibility in critical routing layers and reduce the number of cuts for better yield. The state-of-the-art 2-D DSA process manipulates the orientation of double posts inside guiding templates to guide block copolymers (BCPs) to form 2-D patterns. However, a key challenge arises on how to correctly assign double post orientations and place cut patterns to make desired net connections for a given routing instance. In this paper, we propose a novel 2-D DSA-compliant routing (2-D-DCR) framework to systematically derive feasible orientation assignments for double posts to maximize routability. Specifically, 2-D-DCR features a complete set of new routing rules which transform the underlying physical BCP growth principles for large-scale routing, adopts a network-flow-based double-post assignment routing algorithm, and leverages a 2-D DSA line-end creation property to maximally reduce line-end cuts. Experimental results show that our 2-D-DCR can effectively generate a 2-D-DCR solution with zero double post conflicts, maximized routability, and minimized the number of cuts.

Algade 9 i Aalborg – Husenes udvikling fra vikingetid til nutid

Algade 9 i Aalborg – Husenes udvikling fra vikingetid til nutid

Reactance of Posts in Circular Waveguide

Experimental and numerical simulation results are presented for the reactance of centered variable-height single and double posts in a circular waveguide. The reactance is a function of the waveguide and post dimensions and frequency, and the results presented are useful in the design of a variety of circular waveguide devices involving these elements.

Koustrup –En middelalderlig torp i Vestjylland

Koustrup –En middelalderlig torp i Vestjylland

Correction of the parameters of the equivalent circuit proposed by Montgomery for a two-terminal-pair junction

A correction to the admittance equation of the equivalent circuit for a symmetrical two-terminal-pair junction as proposed by Montgomery is presented. The circuit used by Montgomery is built with two sections of transmission lines separated by a shunt admittance. The mistake in the equation was detected while using that circuit in cascade to model a microwave bandpass filter. A procedure is established and implemented to identily the mistake in the equation. Next, the correct equation is developed using the n equivalent circuit. Samples of double posts in the P-band (two-terminal-pairs junctions) are built and characterised. The experimental S-parameters are applied in the equation proposed by Montgomery and in a procedure by the authors, showing excellent agreement with the latter and a constant error in Montgomery's.

Small‐sized waveguides with periodically loaded double posts

AbstractThe authors have already proposed small‐sized waveguides with periodically loaded posts along a single line placed inside the cut‐off rectangular waveguides. This paper proposes small‐sized waveguides with periodically loaded double posts which have two lines of posts inside the waveguides aiming at an increase of the transmitted power there. The phase constants, the field distribution and other characteristics were obtained theoretically. They were evaluated numerically and these numerical results were confirmed by experimental measurements. This paper considers the transmitted power. Using the same size of the waveguide with a single line of posts, the maximum transmitted power increased by a factor of 1.7 and the transmission losses were reduced by about 6.38 percent by using double posts for the same numerical results of the waveguide with a single line of posts. As in the case of the waveguide with a single line of posts, either slow waves or fast waves can be transmitted. The transmission characteristics can be controlled easier by the values of the reactive loads by the double post structure.