Shape Transformation Research Articles

Physical Environment Analysis of Low-rise Resident Area at the Local Level : The Case of Cheongju-City

The city’s low-rise residence not only displays the characteristics of Korea’s modern and contemporary urban planning but also contributes to the preservation of a distinctive urban landscape. Low-rise residences are urban dwellings comprising small plots and blocks, and they have variable characteristics in contrast to apartment complexes. They are also affected by local environmental and physical factors depending on where they are located in a city. Understanding the construction of low-rise residences and the planning process for each area of living space and physical shape transformation is the first step in the research approach. Second, the study examines the characteristics of the street environment via the lens of the urban landscape. Third, physical aspects such as layouts, building arrangements, and external spatial shapes in low-rise residential area block units are evaluated. By combining the results of block-scale analysis of residential areas, it is reasonable to conclude that low-rise residences form a distinguished urban residential landscape based on a sustainable environment and characteristics that have been preserved by accommodating commercial or residential functions based on the respective circumstances of each city.

Thermadapt Shape Memory Polymers Enabling Spatially Regulated Plasticity.

Converting planar polymer films into sophisticated 3D structures with a facile and effective method is highly challenging yet desirable for device applications in the real world. Dynamic covalent polymer networks enable permanent shape transformations from 2D sheets to 3D structures, but either sophisticated molecular design or a complex fabrication method is required. Here, we report a shape memory polymer cross-linked by ester bonds, which can be activated upon heating after photoexposure to release the catalyst for the transesterification. The region that is activated via the bond exchange can be patterned due to the spatial-temporal selectivity of the photoexposure. Accordingly, the material presents a localized heterogeneity in stress relaxation upon stretching. The exposed and the unexposed regions show respectively plastic deformation and elastic recovery after removal of the external force, which finally make the 2D sheet transform into a 3D structure. The decoupling of the activated region (photoexposure) and activated condition (heating) enables facile chemical design and fabrication for 2D-to-3D shape morphing.

Understanding the mechanism of Nb-MXene bioremediation with green microalgae

Rapidly developing nanotechnologies and their integration in daily applications may threaten the natural environment. While green methods of decomposing organic pollutants have reached maturity, remediation of inorganic crystalline contaminants is major problem due to their low biotransformation susceptibility and the lack of understanding of material surface-organism interactions. Herein, we have used model inorganic 2D Nb-based MXenes coupled with a facile shape parameters analysis approach to track the mechanism of bioremediating 2D ceramic nanomaterials with green microalgae Raphidocelis subcapitata. We have found that microalgae decomposed the Nb-based MXenes due to surface-related physicochemical interactions. Initially, single and few-layered MXene nanoflakes attached to microalgae surfaces, which slightly reduced algal growth. But with prolonged surface interaction, the microalgae oxidized MXene nanoflakes and further decomposed them into NbO and Nb2O5. Since these oxides were nontoxic to microalgal cells, they consumed Nb-oxide nanoparticles by an uptake mechanism thus enabling further microalgae recovery after 72 h of water treatment. The uptake-associated nutritional effects were also reflected by cells’ increased size, smoothed shape and changed growth rates. Based on these findings, we conclude that short- and long-term presence of Nb-based MXenes in freshwater ecosystems might cause only negligible environmental effects. Notably, by using 2D nanomaterials as a model system, we show evidence of the possibility of tracking even fine material shape transformations. In general, this study answers an important fundamental question about the surface interaction-associated processes that drive the mechanism of 2D nanomaterials’ bioremediation as well as provides the fundamental basis for further short- and long-term investigations on the environmental effects of inorganic crystalline nanomaterials.

Nanobowls from Amphiphilic Core–Shell Cyclic Bottlebrush Polymers

Cyclic bottlebrush polymers are macrocycles that contain pendent side-chain polymers on nearly every repeat unit. We leveraged a method to generate cyclic bottlebrush polymers utilizing ring-expansion polymerization (REP) followed by subsequent grafting-from via atom-transfer radical polymerization (ATRP) to produce core–shell cyclic bottlebrush polymers and investigated their self-assembly behavior in water. The bottlebrush polymers were comprised of a cyclic backbone with side chains composed of a hydrophobic polystyrene block and a hydrophilic poly(acrylic acid) block. A two-step morphological transformation from spheres to porous spheres to nanobowls (spheres with a single large pore) was observed with solvent exchange from tetrahydrofuran to water. In contrast, under identical experimental conditions, an analogous linear bottlebrush polymer with a similar backbone and side chain degrees of polymerizations did not aggregate into nanobowls but rather exhibited a porous sphere morphology. These unusual morphologies and their propensities to transform can be attributed to changes in the internal viscosity of the aggregates during the solvent exchange process. Additionally, the rate of solvent exchange was found to influence the propensity for shape transformation to occur.

Surface-Enforced Alignment of Reprogrammable Liquid Crystalline Elastomers.

Liquid crystalline elastomers (LCEs) are stimuli‐responsive materials capable of undergoing large deformations. The thermomechanical response of LCEs is attributable to the coupling of polymer network properties and disruption of order between liquid crystalline mesogens. Complex deformations have been realized in LCEs by either programming the nematic director via surface‐enforced alignment or localized mechanical deformation in materials incorporating dynamic covalent chemistries. Here, the preparation of LCEs via thiol‐Michael addition reaction is reported that are amenable to surface‐enforced alignment. Afforded by the thiol‐Michael addition reaction, dynamic covalent bonds are uniquely incorporated in chemistries subject to surface‐enforce alignment. Accordingly, LCEs prepared with complex director profiles are able to be programmed and reprogrammed by (re)activating the dynamic covalent chemistry to realize distinctive shape transformations.

Mosaic adaptive peak shifts underlie body shape diversification in pelagiarian fishes (Acanthomorpha: Percomorpha)

Abstract Extreme body elongation in fishes is a major evolutionary transformation that extends the boundaries of morphological diversity and alters aspects of function, behaviour and ecology. Prior studies have identified features of the cranial and axial skeleton that characterize elongate fishes, but a lack of detailed reconstructions of anatomical evolution has limited inferences about factors that underlie major shifts in body shape. In this study, we fitted multi-peak adaptive (Ornstein–Uhlenbeck) evolutionary models to species body shape and anatomical dimensions in Pelagiaria, a radiation of open-ocean fishes whose species span a continuum from deep bodied to highly elongate. We inferred an ancestral fusiform adaptive peak that is retained by several major pelagiarian lineages (e.g. Scombridae) and found robust support for multiple transitions to deep-bodied optima (in the families Stromateidae, Bramidae and Caristiidae) and elongate-bodied optima (within Trichiuroidei), including two instances of sequential shifts towards increasingly elongate optima that followed distinct paths of anatomical evolution. Within Trichiuridae, initial increases in head length and the number of vertebrae were followed by changes in head and vertebral shape. Within an elongate-bodied subclade of taxa traditionally identified as ‘gempylids’, changes in head and vertebral shape and in the number of precaudal vertebrae preceded an increase in the number of caudal vertebrae. Altogether, this mosaic of anatomical peak shifts suggests that body shape transformations were associated with differing selective demands and developmental changes.

Facet-selective etching trajectories of individual semiconductor nanocrystals.

The size and shape of semiconductor nanocrystals govern their optical and electronic properties. Liquid cell transmission electron microscopy (LCTEM) is an emerging tool that can directly visualize nanoscale chemical transformations and therefore inform the precise synthesis of nanostructures with desired functions. However, it remains difficult to controllably investigate the reactions of semiconductor nanocrystals with LCTEM, because of the highly reactive environment formed by radiolysis of liquid. Here, we harness the radiolysis processes and report the single-particle etching trajectories of prototypical semiconductor nanomaterials with well-defined crystalline facets. Lead selenide nanocubes represent an isotropic structure that retains the cubic shape during etching via a layer-by-layer mechanism. The anisotropic arrow-shaped cadmium selenide nanorods have polar facets terminated by either cadmium or selenium atoms, and the transformation trajectory is driven by etching the selenium-terminated facets. LCTEM trajectories reveal how nanoscale shape transformations of semiconductors are governed by the reactivity of specific facets in liquid environments.

TRANSFORMASI SPASIAL PADA KORIDOR RUANG JALAN CENDRAWASIH – DEMANGAN BARU YOGYAKARTA

Spatial transformation in corridors road space is a shape transformation of the road space structure and shape from the previous condition to the current condition, including physical and non-physical spaces, namely roads and the scope of road space as a form of a spatial structure. The Cendrawasih – Demangan Baru corridor road space has a strategic location, which is in Depok District as the center of education and economy in Sleman Regency and it is directly next to the Yogyakarta city. It has a direct impact on the Cendrawasih – Demangan Baru corridor road space so it be through a spatial transformation due to the increase of commercial activity in this area. This study used a qualitative rationalistic method with comparative descriptive analysis. This study examined the spatial transformation of the Cendrawasih – Demangan Baru corridor road space from 2006 to 2021 by combining field observations, interviews, and literature studies. Based on the analysis and theoretical study results, there was a significant transformation in the scope of the road space which included a partial transformation to a total transformation, while the roads and pedestrian paths had not changed in their dimensions, but both of them could not fulfill the needs of road space users due to the transformation in the road space scope. The factors causing the transformation were function transformation, ownership transformation and building transformation.

An efficient maximum bound principle preserving p-adaptive operator-splitting method for three-dimensional phase field shape transformation model

In this paper, a novel numerical algorithm for efficient modeling of three-dimensional shape transformation governed by the modified Allen-Cahn (A-C) equation is developed, which has important significance for computer science and graphics technology. The new idea of the proposed method is as follows. Firstly, the operator splitting method is used to decompose the three-dimensional problem into a series of one-dimensional subproblems that can be solved in parallel in the same direction. Secondly, a temporal p-adaptive strategy, which is based on the extrapolation technique, is proposed to improve the convergence order in time and preserve the computational efficiency simultaneously. Finally, a parallel least distance modification technique is developed to force the discrete maximum bound principle. The proposed method achieves high precision and high efficiency at the same time. Numerical examples include the effectiveness of the p-adaptive method and the bound preserving least distance modification, and a series of complex three-dimensional shape transformation modelings. • The operator splitting method is used to solve 3D shape transformation PDE. • A temporal p-adaptive strategy is developed to improve computational efficiency. • A least-distance modification is developed to force the discrete maximum bound.

Neurotransmitter uptake of synaptic vesicles studied by X-ray diffraction

The size, polydispersity, and electron density profile of synaptic vesicles (SVs) can be studied by small-angle X-ray scattering (SAXS), i.e. by X-ray diffraction from purified SV suspensions in solution. Here we show that size and shape transformations, as they appear in the functional context of these important synaptic organelles, can also be monitored by SAXS. In particular, we have investigated the active uptake of neurotransmitters, and find a mean vesicle radius increase of about 12% after the uptake of glutamate, which indicates an unusually large extensibility of the vesicle surface, likely to be accompanied by conformational changes of membrane proteins and rearrangements of the bilayer. Changes in the electron density profile (EDP) give first indications for such a rearrangement. Details of the protein structure are screened, however, by SVs polydispersity. To overcome the limitations of large ensemble averages and heterogeneous structures, we therefore propose serial X-ray diffraction by single free electron laser pulses. Using simulated data for realistic parameters, we show that this is in principle feasible, and that even spatial distances between vesicle proteins could be assessed by this approach.

Digital Light 3D Printed Bioresorbable and NIR-Responsive Devices with Photothermal and Shape-Memory Functions.

Digital light processing (DLP) 3D printing is a promising technique for the rapid manufacturing of customized medical devices with high precision. To be successfully translated to a clinical setting, challenges in the development of suitable photopolymerizable materials have yet to be overcome. Besides biocompatibility, it is often desirable for the printed devices to be biodegradable, elastic, and with a therapeutic function. Here, a multifunctional DLP printed material system based on the composite of gold nanorods and polyester copolymer is reported. The material demonstrates robust near‐infrared (NIR) responsiveness, allowing rapid and stable photothermal effect leading to the time‐dependent cell death. NIR light‐triggerable shape transformation is demonstrated, resulting in a facilitated insertion and expansion of DLP printed stent ex vivo. The proposed strategy opens a promising avenue for the design of multifunctional therapeutic devices based on nanoparticle–polymer composites.

In Situ Direct Monitoring of the Morphological Transformation of Single Au Nanostars Induced by Iodide through Dual-Laser Dark-Field Microscopy: Unexpected Mechanism and Sensing Applications.

Single nanoparticle imaging is a significant technique to help reveal the reaction mechanism and provides insight into the nanoparticle transformation. Here, we monitor the in situ morphological transformation of Au nanostars (GNSs) induced by iodide (I−) in real time using dark-field microscopy (DFM) with 638 nm red (R) and 534 nm green (G) laser coillumination. The two lasers are selected because the longitudinal localized surface plasmon resonance of GNSs is located at 638 nm and that for GNSs after transformation is at 534 nm. Interestingly, I− can interact with GNSs directly without the engagement of other reagents, and upon increasing I− concentrations, GNSs undergo color changes from red to orange, yellow, and green under DFM. Accordingly, green/red channel intensities (G/R ratios) are extracted by obtaining red and green channel intensities of single nanoparticles to weigh the morphological changes and quantify I−. A single nanoparticle sensor is constructed for I− detection with a detection limit of 6.9 nM. Finally, a novel mechanism is proposed to elucidate this shape transformation. I− absorbed onto the surface of GNSs binds with Au atoms to form AuI−, lowering the energy of its bond with other Au atoms, which facilitates the diffusion of this atom across the nanoparticle surface to low-energy sites at the concaves, thus deforming to spherical Au nanoparticles.

Programmable Shape Change in Semicrystalline Liquid Crystal Elastomers.

Liquid crystal elastomers (LCEs) are stimuli-responsive materials capable of reversible and programmable shape change in response to an environmental stimulus. Despite the highly responsive nature of these materials, the modest elastic modulus and blocking stress exhibited by these actuating materials can be limiting in some engineering applications. Here, we engineer a semicrystalline LCE, where the incorporation of semicrystallinity in a lightly cross-linked liquid crystalline network yields tough and highly responsive materials. Directed self-assembly can be employed to program director profiles through the thickness of the semicrystalline LCE. In short, we use the alignment of a liquid crystal monomer phase to pattern the anisotropy of a semicrystalline polymer network. Both the semicrystalline-liquid crystalline and liquid crystalline-isotropic phase transition temperatures provide controllable shape transformations. A planarly aligned sample's normalized dimension parallel to the nematic director decreases from 1 at room temperature to 0.42 at 250 °C. The introduction of the semicrystalline nature also enhances the mechanical properties exhibited by the semicrystalline LCE. Semicrystalline LCEs have a storage modulus of 390 MPa at room temperature, and monodomain samples are capable of generating a contractile stress of 2.7 MPa on heating from 25 to 50 °C, far below the nematic to isotropic transition temperature. The robust mechanical properties of this material combined with the high actuation strain can be leveraged for applications such as soft robotics and actuators capable of doing significant work.

A Highly Multi-Stable Meta-Structure via Anisotropy for Large and Reversible Shape Transformation.

Shape transformation offers the possibility of realizing devices whose 3D shape can be altered to adapt to different environments. Many applications would profit from reversible and actively controllable shape transformation together with a self‐locking capability. Solutions that combine such properties are rare. Here, a novel class of meta‐structures that can tackle this challenge is presented thanks to multi‐stability. Results demonstrate that the multi‐stability of the meta‐structure is strictly tied to the use of highly anisotropic materials. The design rules that enable large‐shape transformation, programmability, and self‐locking are derived, and it is proven that the shapes can be actively controlled and harnessed to realize inchworm‐inspired locomotion by strategically actuating the meta‐structure. This study provides routes toward novel shape adaptive lightweight structures where a metamaterial‐inspired assembly of anisotropic components leads to an unforeseen combination of properties, with potential applications in reconfigurable space structures, building facades, antennas, lenses, and soft robots.

Electrodeposition of alloy PtPd nanocrystals with shape transforming from low–index facet to high–index facet

High–efficient Pt–based electrocatalyst played important role in fuel cell reaction. Shape–controlled synthesis and alloying are two widely used method to optimize electro–catalytic performance of nanoparticles. In this work, we have successfully synthesized shaped PtPd alloy nanocrystals with high–index facet as well as low–index facet via square wave potential (SWP) procedure. The shape transformation from low–index facet to high–index facet could be easily achieved by simply adjusting the parameter of SWP procedure. The periodic adsorption and desorption of hydrogenated or oxygenated species played a key role in the shape–controlled synthesis of PtPd alloy nanocrystals during the process of synthesis. Compared with commercial Pt/C, the prepared PtPd nanocrystals showed great electrocatalytic performance for ethylene glycol oxidation reaction (EGOR). The peak current densities of PtPd convex tetrahexahedral (THH) nanocrystals and PtPd concave nanocubes (NCs) were 21.5 mA ∙ cm−2 and 16.5 mA ∙ cm−2, which were 11.9 and 9.2 times higher than that of commercial Pt/C, respectively. The PtPd alloy nanocrystals also showed much better stability compared with commercial Pt/C. The excellent electro–catalytic performance could attribute to the surface structure and effect of alloying.

Shape Transformations and Self-Assembly of Hairy Particles under Confinement.

Molecular dynamics simulations are used to investigate the behavior of polymer-tethered nanoparticles between two inert or attractive walls. The confinement in pores creates new possibilities for controlling the shape transformation of individual hairy particles and their self-organization. We introduce a minimalistic model of the system; only chain-wall interactions are assumed to be attractive, while the others are softly repulsive. We show how the shape of isolated particles can be controlled by changing the wall separation and the strength of the interaction with the surfaces. For attractive walls, we found two types of structures, “bridges” and “mounds”. The first structures are similar to flanged spools in which the chains are connected with both walls and form bridges between them. We observed various bridges, symmetrical and asymmetrical spools, hourglasses, and pillars. The bridge-like structures can be “nano-oscillators” in which the cores jump from one wall to the other. We also study the self-assembly of a dense fluid of hairy particles in slit-like pores and analyze how the system morphology depends on interactions with the surfaces and the wall separation. The hairy particles form layers parallel to the walls. Different ordered structures, resembling two-dimensional crystalline lattices, are reported. We demonstrate that hairy particles are a versatile soft component forming a variety of structures in the slits.

Noun Structures in the Persian-Dari Dialect of the People of Farah Province in Afghanistan

This study explores the noun groups’ structures in the Persian-Dari dialect of the people of Farah Province in Afghanistan. It aims to bring out the variations between the Standard Persian and the one which is spoken in Farah, in the west of Afghanistan, to analyze if there are any differences in the Farahi Persian dialects. To reveal the various structures of the Persian dialect of Farah residents in the west of Afghanistan, a qualitative approach was adopted. The data for the study was collected both from a spontaneous conversation of the native residents in public places and from the selected conversation among 30 Farah University students. The results of the study revealed some remarkable variations in the daily conversation of the Farahi natives. The changes included reduction, increase, and transformation in shape and of the nouns used in the Persian dialect of the residents of Farah compared to Standard Persian. It is the fact that Farah is neighboring Iran, which has effects on the language dialects. These effects are not only seen in the noun phrases. They are also widely visible in other linguistic units of the people living in Farah.

Effect of alternating magnetic field on microstructure and performance for dissimilar welding-brazing of galvanized steel to 6061 aluminum alloy in an overlapping configuration

In this work, we presented laser welding-brazing of Al/steel dissimilar alloys with alternating magnetic field augmentation. Interfacial microstructures, element distribution and mechanical properties of the joints welded at different magnetic field frequencies were carefully investigated. Formation mechanism of HAZ cracking was also discussed. The results showed that Zn element in the filler metal promoted the occurrence of Fe2 (Al, Zn)5 phase instead of Fe-Al intermetallic compounds at the steel interface, which greatly improved interfacial performance. Columnar crystals at the Al interface were broken into fine dendrites with the aid of the electromagnetic force in the molten metal. Zn-rich products at grain boundaries weakened the cohesions between grains and increased the crack susceptibility. It has been also found that formation of HAZ cracking mainly goes through four stages involving crack inoculation, crack nucleation stage, crack initiation and crack growth. The tensile force and elongation of welded joints subjected to an alternating magnetic field can be increased by 126% and 144%, respectively, compared to that of joints laser welded in the shortage of a magnetic field. Significant improvement in joint performance is attributed to the precipitation of Fe2 (Al, Zn)5 phase and transformation of interface shape.

The Platform Approach

In 2019, the German federal parliament issued a report on a nationwide exit strategy for coal-fired power stations. With this, the Rhenish lignite mining area – a region populated by 2.1 million people and located between Cologne, Aachen, Monchengladbach, and Dusseldorf – was confronted with unprecedented change. The fundamental political decision provoked a multitude of actions on all federal levels of government. Other institutions with historical partnerships in the region, such as the RWTH Aachen University, became embroiled, too. The ongoing transformation process has become an opportunity to rethink and further develop the role of the university as an intermediary in the region. In 2019, a group of researchers from different disciplines set up REVIERa as a transformation platform to strengthen interdisciplinary and transdisciplinary exchange, networking, and coordination. The platform has become an exploratory space both for researchers and regional partners; it has been set up with the hypothesis that knowledge is a key resource to shaping transformation processes. More importantly, it is based on the premise that existing knowledge becomes transformative when new linkages are stimulated. In transformation processes, system, goal, and transformation knowledge are highly related and fluid in the face of highly complex situations and uncertain outcomes. Analogous to the human brain, REVIERa aims to create new synapses that dissolve deadlocked patterns and hence open paths into the future. In this vein, the platform develops innovative methods that follow the principles of reflexivity, resonance, and open learning. This paper addresses the evolution of this platform and evaluates its activities and transformative moments, as well as its inherent contradictions and limitations.

Comparative Study to Analyze MEMS Based Microrobot Using Fuzzy TOPSIS Approach

With the emergence in the field of developing small-scale systems, microrobots are gaining enormous attention due to their small size, wide number of application, and negligible effects on the surrounding. MEMS and microrobots both have electrical and mechanical parts which are situated on a single device and chip. This makes MEMS based microrobots and an excellent device due to its ease of fabrication and small size. MEMS-based microrobots have a wide number of applications in the field of bio-medical special drug delivery and invasive surgery. These tiny robots can be sent into the human body to send any medicine inside the human body. Various types of MEMS based microrobot can be used in drug delivery applications including magnetic nanoparticles based microrobots, magnetized spirulina microrobot, and electro-magnetic microrobots. However, the suitability of all these robots for drug delivery applications depends on the locomotion, navigation controlling, shape transformation, actuation requirement, and amount of drug wasted before moving to the destination. In this work, fuzzy rules based system is performed to confirm the dependence of the parameters including the locomotion, navigation controlling, shape transformation, actuation requirement, and amount of drug wasted on the working of microrobots in drug delivery applications. Similarly, fuzzy TOPSIS based study is performed to compare and analyze the most suitable microrobot for drug delivery application. Piezo-electric and electro-magnetic microrobots are considered the most suitable option with relative closeness to the ideal solution of 0.71 and 0.66, respectively, owing to their better shape transformation and movement.