Frontally polymerizable shape memory polymer for 3D printing of free-standing structures

Four-dimensional (4D) printing is used to describe three-dimensional (3D)-printed objects with properties that change over time. Shape memory polymers (SMPs) are representative materials for 4D printing technologies. The ability to print geometrically complex, free-standing forms with SMPs is crucial for successful 4D printing. In this study, an SMP capable of frontal polymerization featuring exothermic self-propagation was synthesized by adding cyclooctene to a poly(dicyclopentadiene) network, resulting in switching segments. The rheological properties of this SMP were controlled by adjusting incubation time. A nozzle system was designed such that the SMP could be printed with simultaneous polymerization to yield a free-standing structure. The printing speed was set to 3 cm/min according to the frontal polymerization speed. A free-standing, hexagonal spiral was successfully printed and printed spiral structure showed excellent shape memory performance with a fixity ratio of about 98% and a recovery ratio of 100%, thereby demonstrating the 3D printability and shape memory performance of frontally polymerizable SMPs.

Designing Mid-Infrared Gold-Based Plasmonic Slot Waveguides for CO2-Sensing Applications

Plasmonic slot waveguides have attracted much attention due to the possibility of high light confinement, although they suffer from relatively high propagation loss originating from the presence of a metal. Although the tightly confined light in a small gap leads to a high confinement factor, which is crucial for sensing applications, the use of plasmonic guiding at the same time results in a low propagation length. Therefore, the consideration of a trade-off between the confinement factor and the propagation length is essential to optimize the waveguide geometries. Using silicon nitride as a platform as one of the most common material systems, we have investigated free-standing and asymmetric gold-based plasmonic slot waveguides designed for sensing applications. A new figure of merit (FOM) is introduced to optimize the waveguide geometries for a wavelength of 4.26 µm corresponding to the absorption peak of CO2, aiming at the enhancement of the confinement factor and propagation length simultaneously. For the free-standing structure, the achieved FOM is 274.6 corresponding to approximately 42% and 868 µm for confinement factor and propagation length, respectively. The FOM for the asymmetric structure shows a value of 70.1 which corresponds to 36% and 264 µm for confinement factor and propagation length, respectively.

APPLICATION OF MAHAYANA AND VAJRAYANA CONCEPT, AND MANASARA BOOK ON MATARAM SAILENDRA BUDDHIST TEMPLE IN TERMS OF FIGURE, ORNAMENT, MASS AND SPATIAL ORDER

Abstract- Classical Indian architectural principles and traditions has been collected and preserved in a vast body of literature collectively known as the Vāstuśāstra. This branch of classical Indian knowledge is a realization of Hindu ideals in terms of architectural edifice, which significantly influence the religious architecture of the Indian cultural sphere which extends to the medieval Island of Java. Indian influence can be seen in Hindu temples of Java during the Śailendra’s dynasty even though some of it’s architectural elements can’t be found in vāstuśāstra. However, in contrast of Hindu’s vāstuśāstra, Buddhism has no architecture guideline and free standing structure as of sources that are used as it’s guide are questioned, especially Buddhist Temples in Central Java during ancient Mataram’s Dynasty of Śailendra. Although Buddha’s teachings and some parts of vāstuśāstra are known to play a role in the construction of Buddhist Temples in Indonesia, how far they are applied is difficult to observe, giving the absence of special studies and free standing temple references to build Buddhist Temple, and it’s interviewees are gone. By finding information about architecture’s theory of Buddha’s teachings that entered Indonesia and identify as well as compare the relevant parts of vāstuśāstra, then the architectural elements that are part of the concept of Buddha’s teachings and vāstuśāstra can be seen.In this research, descriptive method and qualitative approach are used by the author. The author focused in terms of figure and ornament as well as mass and spatial order. This research collects and compares parts of vāstuśāstra that are relevant as well as Buddha’s teachings concept to compare them with datas from the twelve samples of Buddhist Temples in Central Java during ancient Mataram’s Dynasty of Śailendra. Comparison by the author shows a number of results. Firstly, the concept of mahāyāna, vajrayāna, and mānasāra book applied in terms of figure, ornament, mass, and spatial order are seen in Central Java’s Buddhist Temples. However, various architectural details of these elements have marked differences from what is instructed in the Vāstuśāstra. The distinctive Javanese Kala-Makara for example, does not conform the mānasāra book. Secondly, the application of mānasāra book concepts in Central Java’s Buddhist Temples prove the influence of Hinduism which was affected by the harmonious relationship between Buddhism and Hinduism during that time. Lastly, the first free-standing Buddhist Temples is 5th Batujaya Temple/Blandongan Temple (2-3 CE and 7-10 CE) because the Mahabodhi Temple in India was built as we see today during the 6th restoration phase (8 CE).

Near-field cavity optomechanical coupling in a compound semiconductor nanowire

A III-V compound semiconductor nanowire is an attractive material for a novel hybrid quantum interface that interconnects photons, electrons, and phonons through a wavelength-tunable quantum structure embedded in its free-standing structure. In such a nanomechanical element, however, a challenge is how to detect and manipulate a small number of phonons via its tiny mechanical motion. A solution would be to couple an optical cavity to a nanowire by introducing the ‘cavity optomechanics' framework, but the typical size difference between them becomes a barrier to achieving this. Here, we demonstrate near-field coupling of a silica microsphere cavity and an epitaxially grown InP/InAs free-standing nanowire. The evanescent optomechanical coupling enables not only fine probing of the nanowire’s mechanical motion by balanced homodyne interferometry but also tuning of the resonance frequency, linewidth, Duffing nonlinearity, and vibration axis in it. Combining this cavity optomechanics with epitaxial nanowire engineering opens the way to novel quantum metrology and information processing.

Discovery of Alfven waves planetward of the Rings of Saturn

<p>Between April and September 2017 in the final stages of the Cassini Saturn Orbiter mission the spacecraft executed 22 orbits passing planetward of the innermost ring, the D-ring.  During periapsis passes on all these orbits oscillations were detected in the azimuthal magnetic field components on typical time scales from a few minutes to 10 minutes. We argue that the time-varying signals detected on the spacecraft are also primarily time-varying in the plasma frame.  Nonetheless, we show that nearly all signals exhibit a distinct spatial effect, namely a magnetic node near the effective field line equator.  The oscillations thus have a standing structure along the background magnetic field and it follows that they are field line resonances associated with Alfvén waves.  The form of the signals suggests that the local field line resonances are most likely pumped from global sources.  This is the first detection in a giant planet magnetosphere of a phenomenon known to be important at Earth.</p>

Near-field cavity optomechanical coupling in a compound semiconductor nanowire

A III-V compound semiconductor nanowire is an attractive material for a novel hybrid quantum interface that interconnects photons, electrons, and phonons through a wavelength-tunable quantum structure embedded in its free-standing structure. In such a nanomechanical element, however, a challenge is how to detect and manipulate a small number of phonons via its tiny mechanical motion. A solution would be to couple an optical cavity to a nanowire by introducing the "cavity optomechanics" framework, but the typical size difference between them becomes a barrier to achieving this. Here, we demonstrate near-field coupling of a silica microsphere cavity and an epitaxially grown InP/InAs free-standing nanowire. The evanescent optomechanical coupling enables not only fine probing of the mechanical motion by balanced homodyne interferometry but also tuning of the resonance frequency, linewidth, Duffing nonlinearity, and vibration axis in the nanowire. Combining this cavity optomechanics with epitaxial nanowire engineering opens the way to novel quantum metrology and information processing.

Defining Rome’s Pantheum

Writing in the early third century AD, Julius Africanus claimed to have built a library “in the Pantheon” in Rome, the exact location of which remains elusive. In considering the competing possibilities for the site of the library, this paper argues that the building we commonly refer to as the Pantheon does not correspond to the ancient understanding of what the Pantheum was. The case is made that it was not a single building, but instead comprised a larger complex, of which the still-standing structure was only one part. This interpretation allows for a number of details associated with the Pantheon to be rethought within a wider context and alternative proposals advanced regarding the forecourt in front of porch, the “arch” in the centre of this space, the location of the now lost caryatids and bronze columns, the little understood Severan restoration, and the meanings of the much-discussed inscriptions on the façade.

Mitigation of Rocking and Sliding Motion of a Free-Standing Structure Subjected to Base Excitation Using Coaxial Circular Cylinders Containing Highly Viscous Liquid in Annular Spaces

In this study, the effectiveness of coaxial circular cylinders containing a highly viscous liquid in annular spaces for reduction of rocking motion of a free-standing structure is investigated both analytically and experimentally. First, an analytical model of coupled rocking and sliding motions of a free-standing structure, including the coaxial circular cylinders, subjected to seismic input was derived. The free-standing structure was modeled as a free-standing rigid body. The cylinders were attached to the bottom of the rigid body as a damping device. We then experimentally derived the friction coefficients, inertia moments, and a damping coefficient in the rotating direction. Furthermore, using these parameters, the effectiveness of this system in suppressing the rocking motion is investigated analytically. The proposed method was determined to be very effective in suppressing the rocking motion of a rigid body subjected to a seismic input by the experiment.