Large Folds Research Articles

Rapid multi-physics simulation for electro-thermal origami systems

Electro-thermally actuated origami provides a novel method for creating 3-D systems with advanced morphing and functional capabilities. However, it is currently difficult to simulate the multi-physical behavior of such systems because the electro-thermal actuation and large folding deformations are highly interdependent. In this work, we introduce a rapid multi-physics simulation framework for electro-thermally actuated origami systems that can simultaneously capture: thermo-mechancially coupled actuation, inter panel contact, heat transfer, large deformation folding, and other complex loading applied onto the origami. Comparisons with finite element models validate the proposed framework for simulating origami heat transfer with different system geometries, materials, and surrounding environments. Verification of the simulated folding behaviors against physical electro-thermal micro-origami further demonstrates the validity of the proposed model. Simulations of more complex origami patterns and a case study for origami optimization are provided as application examples to show the capability and efficiency of the model. The framework provides a novel simulation tool for analysis, design, control, and optimization of active origami systems, pushing the boundary for feasible shape morphing and functional capability.

Late Oligocene\u2014Early Miocene shortening in the Thrace Basin, northern Aegean

Late Cenozoic was a period of large-scale extension in the Aegean. The extension is mainly recorded in the metamorphic core complexes with little data from the sedimentary sequences. The exception is the Thrace Basin in the northern Aegean, which has a continuous record of Middle Eocene to Oligocene marine sedimentation. In the Thrace Basin, the Late Oligocene–Early Miocene was characterized by north-northwest (N25°W) shortening leading to the termination of sedimentation and formation of large-scale folds. We studied the stratigraphy and structure of one of these folds, the Korudağ anticline. The Korudağ anticline has formed in the uppermost Eocene–Lower Oligocene siliciclastic turbidites with Early Oligocene (31.6 Ma zircon U–Pb age) acidic tuff beds. The turbidites are underlain by a thin sequence of Upper Eocene pelagic limestone. The Korudağ anticline is an east-northeast (N65°E) trending fault-propagation fold, 9 km wide and 22 km long and with a subhorizontal fold axis. It is asymmetric with shallowly-dipping northern and steeply-dipping southern limbs. Its geometry indicates about 1 km of shortening in a N25°W direction. The folded strata are unconformably overlain by Middle Miocene continental sandstones, which constrain the age of folding. The Korudağ anticline and other large folds in the Thrace Basin predate the inception of the North Anatolian Fault (NAF) by at least 12 myr. The Late Oligocene–Early Miocene (28–17 Ma) shortening in the Thrace Basin and elsewhere in the Balkans forms an interlude between two extensional periods, and is probably linked to changes in the subduction dynamics along the Hellenic trench.

Development of a Software Tool for Identifying Protein Sequence Interdependencies from Multiple Sequence Alignments

Introduction Computational methods for evaluating protein structure have led to a deepened understanding of how aligned sequences of amino acid chains may be used to infer structural relationships. We developed a pattern discovery program for predicting and visualizing higher order group relationships and their correspondences from large scale multiple sequence alignments across multiple species that can enhance the understanding of submolecular protein structure, even for proteins that do not have a solved structure. Methods We developed PSICalc (Protein Sequence Interdependency Calculator) software, using a novel algorithm based originally on the k-modes algorithm that clusters substructural components using normalized mutual information as a measure of intra-site interdependency [Durston, K.K., Chiu, D.K.Y., Wong, A.K.C., Li, G.C.L., Statistical discovery of site inter-dependencies in sub-molecular hierarchical protein structuring, EURASIP J Bioinform Syst Biol. (2012) Jul 13;2012(1):8. doi: 10.1186/1687-4153-2012-8]. To aid in visualizing interactions across multiple subdomains, we developed PSICalc Viewer, a complete graphical user interface that allows researchers to provide a multiple sequence alignment and a set of available input parameters to visualize predicted protein structure as a polytree graph. Results The structure of ubiquitin is well-known and served as a base case for validating the amino acid pairs and groupings identified by the algorithm. The algorithm was able to correctly group amino acids into pairs and clusters representing features of the three dimensional structure of ubiquitin. As one example, the algorithm clustered amino acids 27, 41, and 52, which represent adjacent positions in the three dimensional structure of ubiquitin (1UBQ). Additionally, the algorithm identified pairs and clusters of amino acids around the ATP binding pocket of the ATPase domain of topoisomerase II using a dataset of HATPase domains from the Pfam database. Conclusions The software tool employs the PSICalc algorithm, which allows the researcher to predict features of submolecular protein structure. The pairs and clusters of amino acids identified by the algorithm appear to have structural relevance either through close interactions or mutual participation in larger folds or domains. Additional studies are currently being pursued to apply the software tool to other proteins of interest. It is expected that this tool will aid in the examination of proteins of unknown structure through identification of submolecular interdependencies in protein sequences.

Anatomical and morphometric evaluation of the orbit, eye tunics, eyelids and orbital glands of the captive females of the South African painted dog (Lycaon pictus pictus Temminck, 1820) (Caniformia: Canidae).

In this study, we present the first data concerning the anatomical, morphometrical, histological and histochemical study of the orbit, eye tunics, eyelids and orbital glands in South African Painted Dogs (Lycaon pictus pictus). The study was performed using eyeball morphometry, analysis of the bony orbit including its morphometry, macroscopic study, morphometry, histological examination of the eye tunics and chosen accessory organs of the eye and histochemical analysis. The orbit was funnel shaped and was open-type. There was a single ethmoid opening for the ethmoid nerve on the orbital lamina. The pupil was round, while the ciliary body occupied a relatively wide zone. The iris was brown and retina had a pigmented area. The cellular tapetum lucidum was semi-circular and milky and was composed of 14–17 layers of tapetal cells arranged in a bricklike structure. In the lower eyelid, there was a single conjunctival lymph nodule aggregate. One or two additional large conjunctval folds were observed within the posterior surface of the upper eyelids. The superficial gland of the third eyelid had a serous nature. The third eyelid was T-shaped and was composed of hyaline tissue. Two to three conjunctival lymph nodul aggregates were present within the bulbar conjunctiva of the third eyelid. The lacrimal gland produced a sero-mucous secretion. A detailed anatomic analysis of the eye area in the captive South African Painted Dogs females showed the similarities (especially in the histological examination of the eyetunics and orbital glands) as well as the differences between the Painted dog and the other representatives of Canidae. The differences included the shape and size od the orbita with comparison to the domestic dog. Such differences in the orbit measurements are most likely associated with the skull type, which are defined in relation to domestic dogs. The presented results significantly expand the existing knowledge on comparative anatomy in the orbit, eye and chosen accessory organs in wild Canidae.

High-permeability zones in folded and faulted silicified carbonate rocks – Implications for karstified carbonate reservoirs

Ascending hydrothermal fluid flow and subsequent hypogene karstification can control the formation of high-permeability zones in folded or faulted carbonate rocks. This study presents a multidisciplinary and multiscale approach to investigate the relationships between regional deformation and subseismic karst conduits along fracture corridors. We investigate the Cristal Cave Karst System, which is 6.7 km long and occurs in Mesoproterozoic carbonate-siliciclastic units affected by hydrothermal silicification in the São Francisco Craton, Brazil. Based on integrated techniques of ALOS PALSAR imagery, structural field surveys, stratigraphic and laboratory analyses in the caves and the surrounding surface outcrops, we highlight the following points: (1) the cave system occurs in a regional folded sector; (2) the internal architecture of the large regional folds is composed of subseismic folds; (3) fracture corridors occur along the subseismic fold hinges, forming high-permeability zones; and (4) the principal cave passages, which are oriented NNE-SSW, are concentrated along these fold hinges. We discuss the results in terms of a spatiotemporal conceptual model and unravel the deformation and karstification stages, which are characterized by the development of (i) precontractional and (ii) contractional structural networks followed by (iii) hydrothermal silicification and karstification processes. This cave system can be used as an analog for deformed, silicified, and karstified carbonate reservoirs, allowing for the in situ characterization of subseismic structural features. This study provides the key for first-order prediction and characterization of high-permeability zone internal structures, where both deformation and karstification processes occur.

Simulation of Folding Kinetics for Aligned RNAs.

Studying the folding kinetics of an RNA can provide insight into its function and is thus a valuable method for RNA analyses. Computational approaches to the simulation of folding kinetics suffer from the exponentially large folding space that needs to be evaluated. Here, we present a new approach that combines structure abstraction with evolutionary conservation to restrict the analysis to common parts of folding spaces of related RNAs. The resulting algorithm can recapitulate the folding kinetics known for single RNAs and is able to analyse even long RNAs in reasonable time. Our program RNAliHiKinetics is the first algorithm for the simulation of consensus folding kinetics and addresses a long-standing problem in a new and unique way.

Botulinum toxin injections as an effective treatment for patients with intertriginous Hailey-Hailey or Darier disease: an open-label 6-month pilot interventional study

BackgroundPatients with Hailey-Hailey and Darier diseases present with disabling inflammatory lesions located in large skin folds, which are often exacerbated or induced by sweating. Quality of life is highly impaired because of pain and recurrent skin infections. An improvement in skin lesions after botulinum toxin A injections has previously been reported in some patients but no prospective interventional studies are available. The aim of this open-label, 6-month, interventional pilot study (NCT02782702) was to evaluate the effectiveness and safety of botulinum toxin A for patients with moderate to very severe skin lesions located in folds.ResultsThirty patients (26 Hailey-Hailey/4 Darier) were included. Botulinum toxin A proved effective within the first month in two-thirds of patients, taking all study parameters (itchiness, cutaneous pain, sweating and odour, infections, psychosocial impairment and quality of life) into account and persisted during the 6-month follow-up period. No patient was classed as a BtxA non-responder, but 11 (37%) Hailey-Hailey patients (the most severe ones), experienced a relapse during the study. No serious side effects were reported. Mild transient clear fluid discharge at the site of the injections was reported for 27% of patients.ConclusionsBotulinic toxin seems to be an effective and safe treatment for Hailey-Hailey and Darier diseases. Nevertheless, it may prove insufficient for the severest of Hailey-Hailey cases and could be considered as supplementary to other conventional treatments. Further studies are required to confirm our results on larger Darier cohorts.

Tectonic Fabric, Geochemistry, and Zircon-Monazite Geochronology as Proxies to Date an Orogeny: Example of South Delhi Orogeny, NW India, and Implications for East Gondwana Tectonics

We have dated the South Delhi orogeny, Aravalli-Delhi Mobile Belt (ADMB), NW India, using the tectonic fabric, geochemistry, and zircon-monazite geochronology as the proxies. The South Delhi Terrane (SDT), a passive margin domain in the ADMB, consists of multiply deformed (D1–D4) greenschist facies rocks and several granite plutons. The D1deformation is characterized by pervasive isoclinal recumbent F1fold and axial planar tectonometamorphic fabric, S1, developed in all rock types. The S1minerals belong to peak greenschist facies metamorphism, M1, suggesting syntectonic nature of M1with D1. The age of the D1-M1is constrained by the syncollisional peralkaline S type Sewariya granite which is characterized by magmatic/submagmatic fabric (Sm) coplanar with the S1. The margin of the pluton is turned into quartzofeldspathic gneiss carrying the evidence of high temperature deformation. The age of Sewariya granite is estimated at ca. 878 Ma by zircon geochronology. The D1-M1is further constrained by monazite geochronology of the mica schist at ca. 865–846 Ma. The other granite plutons and metarhyolite are pre-D1and emplaced at ca. 992–946 Ma. The D2deformation produced NE-SW trending open upright F2folds coaxial with the F1, and northwesterly vergent F2–axial planar thrusts. Monazite geochronology constrains the D2at ca. 811–680 Ma. The D3is characterized by small to large scale NW-SE folds, and the D4by faults and fractures marking the brittle deformation in the rocks. The D4is constrained by monazite geochronology at ca. 588–564 Ma. There are upper amphibolitic tectonic slivers along the D2-Phulad thrust, belonging to the pre-Delhi rocks, which show ca. 1,638 Ma metamorphism age. From the above study, it is suggested that the South Delhi orogeny belongs to ca. 878–680 Ma marking the final amalgamation of Marwar Craton with the rest of India. This overlaps the early phase of the Pan-African orogeny (900–630 Ma). The brittle deformation, D4, coincides with Kuunga orogeny (650–500 Ma). Our study implies that India, like other continents in the East Gondwana, underwent amalgamation of internal blocks until the late part of the Neoproterozoic.

Review of Deployable Mechanism Test Technologies Oriented Towards Deep Space Exploration

Space deployable mechanisms refer to the mechanisms that can be folded into a compact configuration and be deployed into a large predetermined shape. With the development of deep-space exploration, deployable mechanisms become one of the best choices for the deep- space probes. Large-scale, large folding ratio, high stiffness and lightweight have become the development trend of deployable mechanisms, leading to the high demands for validation of the field test. During the design and production stage, many special tests for the mission goals and the space environment need to be carried out besides the traditional spacecraft tests. In this paper, some typical tests of deployable mechanism for deep space exploration are analysed, the scheme and the performance of the special test program are summarized, such as the low gravity simulation and the vibration test. In addition, some suggestion is also made for future test methods and technology development.

Nature and origin of large-scale and intrasalt deformation within the Wieliczka salt mine, Poland

The Wieliczka salt mine, near Kraków in southern Poland, is a world-famous historical and modern destination for both geoscientists and tourists. Despite numerous publications, there is still a lack of consensus on the nature and origin of the large-scale folds as well as whether the small-scale structures represent tectonic or soft-sediment deformation. In this preliminary work, we offer new ideas on both aspects. At the large scale, we emphasize the mechanical stratigraphy of the layered evaporite sequence, which comprises a thin basal weak layer, a thin strong unit, a thicker weak layer, and a thicker strong unit. We suggest that the inclined to recumbent folds and thrusts formed tectonically due to overthrust shear between the basal detachment and the overriding Carpathian frontal thrust, with different structural styles decoupled by the thick weak layer. At the small scale, we suggest that there was early extension directed toward the east to north-east, followed by contraction vergent toward the north. We infer that there was early, syndepositional gravity gliding down a topographic slope dipping into the coeval Gdów depocenter to the east, and that subsequent north-directed Carpathian shortening generated the small-scale contractional structures as the larger folds were developing

Validation of DBFOLD: An efficient algorithm for computing folding pathways of complex proteins.

Atomistic simulations can provide valuable, experimentally-verifiable insights into protein folding mechanisms, but existing ab initio simulation methods are restricted to only the smallest proteins due to severe computational speed limits. The folding of larger proteins has been studied using native-centric potential functions, but such models omit the potentially crucial role of non-native interactions. Here, we present an algorithm, entitled DBFOLD, which can predict folding pathways for a wide range of proteins while accounting for the effects of non-native contacts. In addition, DBFOLD can predict the relative rates of different transitions within a protein's folding pathway. To accomplish this, rather than directly simulating folding, our method combines equilibrium Monte-Carlo simulations, which deploy enhanced sampling, with unfolding simulations at high temperatures. We show that under certain conditions, trajectories from these two types of simulations can be jointly analyzed to compute unknown folding rates from detailed balance. This requires inferring free energies from the equilibrium simulations, and extrapolating transition rates from the unfolding simulations to lower, physiologically-reasonable temperatures at which the native state is marginally stable. As a proof of principle, we show that our method can accurately predict folding pathways and Monte-Carlo rates for the well-characterized Streptococcal protein G. We then show that our method significantly reduces the amount of computation time required to compute the folding pathways of large, misfolding-prone proteins that lie beyond the reach of existing direct simulation. Our algorithm, which is available online, can generate detailed atomistic models of protein folding mechanisms while shedding light on the role of non-native intermediates which may crucially affect organismal fitness and are frequently implicated in disease.

Large Curvature Folding Strategies of Butterfly Proboscis

Due to its real-time control, high folding ratio, and structure self-locking, flexible large curvature self-folding devices have broad application prospects, such as foldable human implants, flexible electronics, and flexible robots. Driven by this background, flexible large curvature folding butterfly (Polyura eudamippus) proboscises were studied in this work. The folding ratio of the proboscises was about 15. The curvature of coiled proboscises ranged from about 150 m−1 to 880 m−1. The external and internal structures of the proboscises were studied by different methods. Three main strategies for large-curvature folding of proboscises were identified: a gradual decrease in thickness, a lower elastic modulus, and (most importantly) large numbers of regular corrugated cracks arranged on the surface. These corrugated cracks can effectively accommodate the coiled strain and provide space for the large curvature folding of proboscises. Finally, a 4D printed coiled sample with corrugated cracks was fabricated to mimic the proboscises stretching process. Large-curvature folding strategies, based on these proboscises, provide insights for the biomimetic design of artificial highly folded components.

Deformation Structures in a Large Slump Horizon, Paleoproterozoic Vempalle Formation, Cuddapah Basin, Southern India

Occurrence of slump folds and associated faults generated by soft-sediment deformation from the Paleoproterozoic Vempalle Formation, southwestern Cuddapah basin, India, is being reported here for the first time. The slump horizon is preserved within a more or less undeformed shallow to deep-water carbonate unit in the Cuddapah basin exposed near Parnapalle village, Andhra Pradesh, India. The stratigraphic framework includes the Gulcheru Quartzite, lowermost unit of the Cuddapah basin succession, deposited in an alluvial to shallow marine shelf environment, and the overlying Vempalle Formation, representing a ramp-type stromatolitic carbonate platform. The synsedimentary sliding along a steepened ramp is evidenced by northeast-verging kink-like folds with wavelength up to 400 m and an overprinting set of thrusts with ramp-flat geometry, fault-cored folds or small break-thrusts showing top-to-southwest displacement, and smaller congruent folds. From the isolated occurrence within a generally undeformed succession, association of structures, and the stratigraphic context, we suggest soft-sediment deformation at the toe of a large (kilometer-scale) slump, with the prevalent bedding-parallel anisotropy exploited for common flexural slip and ramp-flat geometry. In addition, the bedding-parallel slickensides in the Gulcheru Quartzite immediately below the Vempalle Formation indicate a top-to-east-northeast, normal sense of slip representing extensional slip at the slump head. Northeast-verging large folds in the Parnapalle slump horizon possibly represent structures formed during the translation phase of slumping. As the large northeast propagating slump was halted, the backthrust-like structures and associated folds developed at the slump toe.

Solution NMR readily reveals distinct structural folds and interactions in doubly 13C- and 19F-labeled RNAs.

RNAs form critical components of biological processes implicated in human diseases, making them attractive for small-molecule therapeutics. Expanding the sites accessible to nuclear magnetic resonance (NMR) spectroscopy will provide atomic-level insights into RNA interactions. Here, we present an efficient strategy to introduce 19F-13C spin pairs into RNA by using a 5-fluorouridine-5'-triphosphate and T7 RNA polymerase-based in vitro transcription. Incorporating the 19F-13C label in two model RNAs produces linewidths that are twice as sharp as the commonly used 1H-13C spin pair. Furthermore, the high sensitivity of the 19F nucleus allows for clear delineation of helical and nonhelical regions as well as GU wobble and Watson-Crick base pairs. Last, the 19F-13C label enables rapid identification of a small-molecule binding pocket within human hepatitis B virus encapsidation signal epsilon (hHBV ε) RNA. We anticipate that the methods described herein will expand the size limitations of RNA NMR and aid with RNA-drug discovery efforts.

S3588 Chronic Lymphocytic Gastritis

INTRODUCTION: Lymphocytic gastritis (LG) is an uncommon cause of chronic gastritis, accounting for only 5% of cases. The pathology has no clear etiology, however, it is frequently associated with Celiac disease, found in approximately 40% of the patients. H. pylori infection, Crohn’s disease, HIV infection and lymphoma have also been associated in patients with LG. CASE DESCRIPTION/METHODS: A 37-year-old woman with no relevant past medical history who presented to the GI clinic for evaluation of iron deficiency anemia, change in bowel habits, chronic tenesmus and dyspepsia. Menstrual history was unremarkable and anemia did not improved with oral iron supplementation. Laboratory studies showed microcytic normochromic anemia, with an RDW of 15%. Iron profile was consistent with iron deficiency (serum iron of 25 µg/dL and ferritin of 14 ng/mL). Further work up included thyroid studies, vitamin B12 level and testing for celiac disease, which all resulted negative. Subsequent endoscopy and colonoscopy evaluation were unremarkable for macroscopic abnormalities, however, gastric biopsies revealed increased intraepithelial lymphocytosis suggesting a diagnosis of lymphocytic gastritis confirmed via CD3 stain. Colonic biopsies revealed chronic inflammation of lamina propia with intraepithelial lymphocytosis and positive CD3 stain. The patient was started on esomeprazole for lymphocytic gastritis and budesonide for lymphocytic colitis with improvement of symptoms. DISCUSSION: LG is commonly present in middle aged adults, affecting both male and females equally. Initial symptoms are usually non-specific and vary from dyspepsia, nausea, vomiting, diarrhea, anorexia and weight loss. Up to 20% of the cases are labeled as idiopathic, but commonly associated conditions thought to contribute to LG development include autoimmune diseases, infection or environmental influences. Upper endoscopy findings can show nodules, erosions, large gastric folds, or no abnormalities. Diagnosis is achieved by means of histopathological findings, with >25 lymphocytes per 100 epithelial cells. The treatment consists of symptomatic relief, with PPIs or with H. pylori eradication; however, some patients exhibit spontaneous remission. We present this case of refractory iron deficit anemia due LG in a rare location outside the colon resulting in malabsorption.Figure A.: H&E stain of biopsy from nodular gastric mucosa demonstrating increased intraepithelial lymphocytes and expanded lamina propria. Figure B: CD3 stain demonstrated predominant CD3 positive T cells with CD8 co-expression.

Forced folding in the Kora Volcanic Complex, New Zealand: A case study with relevance to the production of hydrocarbons and geothermal energy

The intrusion of magma into relatively shallow strata often results in structural deformation. Forced folds are typically formed above intrusions so as to accommodate the addition of new volumes of magma into the sedimentary pile. This work uses a high-resolution 3D seismic volume from the offshore Taranaki Basin, New Zealand to investigate large forced folds formed in Upper Cretaceous-Paleocene sequences due to the intrusion of magmatic dikes and sills. These magmatic intrusions are related to the plumbing system of the Kora volcano. We apply a novel filtering technique to enhance the contrast between the dip-azimuth of seismic reflectors and that of any overprinting noise, preserving the lateral continuity of seismic events. Forced folds were generated by the intrusion of flat-laying saucer-shaped sills into shallow strata. These folds (Fold A and Fold B) have a domal geometry and a structural relief of 250−350 m, for a total area of 45 km2 and 35 km2, respectively. Out of the 18 interpreted sills, two sills (S1 and S4) contributed the most to the generation of the forced folds in the study area. The sill-fold relationships observed in this work suggest that sills with greater length-to-intrusion ratios deform the strata more effectively. However, it is also clear that forced folds are, in parts of the study area, larger than the intruded sills below. This hints at the presence of a larger volume of intruded magma than that imaged on seismic data where forced folds are significantly larger than the volume of the sills below. Such a character makes the establishment of fold-sill relationships crucial to the identification of magmatic bodies below forced folds - if one identifies a large forced fold on seismic profiles, but only a few small sills are imaged, then the mass of igneous rock below the fold is potentially larger than that imaged on seismic data. More importantly, forced folding in the Taranaki Basin is shown to have led to the development of four-way closures to form prolific traps for hydrocarbon and geothermal energy resources.

Structural interpretation of thrust fault-related landforms on Mercury using Earth analogue fault models

The Yakima Fold Province has often been referenced as an Earth analogue to thrust fault-related landforms on many solar system bodies including Mars, the Moon, and Mercury. The asymmetric ridges of deformed flood basalts in this region evoke the morphology and topographic expression of the landforms observed in the Smooth Plains units of Mercury. Observed similarities have supported the interpretation that thrust faults and folds comprise both sets of landforms; however, this is an incomplete analogy. Recent modeling efforts have revealed that the terrestrial landforms developed over millions of years with vertical uplift associated with each landform accumulating on multiple faults and accommodated by large folds. These studies highlight the important role that folding plays in accommodating crustal shortening. Work presented here uses the structural geometries and folding styles from the Yakima Fold Province as a framework for constructing ten three-dimensional models of thrust fault-related landforms in Smooth Plains units near Suisei Planitia on Mercury, which traditionally would have been classified as “wrinkle ridges” based on appearance and some aspects of morphology. Forward modeling of topography revealed that multiple faults and folds are necessary to reproduce complex topographic features. Folding was found to account for >50% of vertical uplift associated with the landforms and without considering folding, shortening accommodated by the landforms was underestimated by 61 to 88%. Studies which use thrust fault-related landforms as proxies for stress and strain must therefore consider the effect of folding on these estimates and their associated effect on tectonic and thermal histories.

Four-dimensional printed self-deploying circular structures with large folding ratio inspired by origami

Inspired by the origami, a series of smart circular structures with large folding ratio was designed and fabricated by four-dimensional printing in this article. The structure consists of the crease and plate parts by embedding the Miura-ori into a folding fan, and has the characteristics of bi-stable states and self-deployment by introducing soft and hard shape memory polymers. The shape memory polymer material parameters were obtained by the dynamic-mechanical analyzer, and then the constitutive equation can be determined. To demonstrate the folding and deployment performance of the smart structures, the experiment and finite element simulation was carried out. It is shown that the structures can repeatedly be folded and deployed by temperature-controlled shape memory effect of shape memory polymer. This design can be applied to the large-scale and multiple level smart structures such as antennas and deployable solar sails.

Structural design and dynamic analysis of new ultra-large planar deployable antennas in space with locking systems

The ultra-large microwave-transmitting antenna has attracted great research interest in Space Solar Power Station (SSPS). This study aims to explore the design of a new type of ultra-large planar deployable structures for SSPS. This structure has the merits of a large folding ratio and reliable new driving/locking systems with high stiffness. The primary novelty is the new planar deployable structure, of which the basic module is composed of three square units. On the opposite sides of the square unit, torsion springs in the driving/locking systems provide the driving force for deployment. There are three types of driving/locking systems and two types of member bars in each planar deployable structure, which can deploy in both horizontal and vertical directions from the initial folded state. In the thickness direction, there exists an option between deployable (with driving/locking systems) and undeployable (without driving/locking systems) scheme. We describe the design details and working principle of driving/locking systems. The deployment of the basic module is then simulated. Considering the carrying capacity of the future heavy launchers, a large deployable subarray, which consists of the repeating modules, with a full length of 50 m and a width of 7 m is designed and analyzed. Moreover, the initial folded size of the subarray is only 4.8 m × 4.8 m. Finally, we propose a SSPS model with one 200 m-caliber antenna composed of multiple subarrays and two 600 m-length solar cell arrays. Dynamic analysis for this SSPS model shows that the stiffness of this basic deployable structure satisfies the requirements of ultra-large SSPS's performance.

Seismic attributes and analogs to characterize a large fold in the Taranaki Basin

The Taranaki Basin lies in the western portion of New Zealand, onshore and offshore. It is a Cretaceous rift basin that is filled with up to approximately 10 km thick deposits from marine to deepwater depositional environments from the Cretaceous (approximately 93 ma) to the Neogene (approximately 15 ma). This basin underwent important tectonic events that resulted in large-scale features such as faults and folds and the deposition of turbidites such as channels and channel belts. These features easily are recognizable in seismic data. When analyzing the offshore 3D Pipeline data set, we recognized a peculiar fault-like feature with large-scale dimensions (approximately 15 km long and approximately 1 km wide) within the sequence. The alignment was perpendicular to the direction of deposition in the basin (southeast–northwest) as identified by previous studies and subparallel to the main structures in the area (southwest–northeast). We interpreted the seismic character of the funny-looking thing (FLT) likely as (1) a fault, (2) a fold, or (3) a large channel belt within the basin. We use seismic attributes such as coherence (Sobel filter), dip, cosine of phase, and curvature to characterize this feature geomorphologically. The geologic background of the area and analog settings aided in understanding and distinguishing the nature of this large structure. Monocline examples in seismic data are rare to find, and we want to show how to avoid misinterpretations. Geological feature: Fault-bend fold or large-amplitude fold (possibly monocline) Seismic appearance: Large, discontinuous, high-variance feature Alternative interpretations: Fault, fold Features with a similar appearance: Fault, fold, wide straight channel belt (time or horizon slice) Formation: Rift sequence of the Taranaki Basin Age: Eocene Location: Taranaki Basin, Western offshore New Zealand Seismic data: Provided by New Zealand Petroleum and Minerals Contributors: Karelia La Marca, Heather Bedle, Jerson Tellez; School of Geosciences; University of Oklahoma, Norman, OK, USA Analysis tool: 3D reflection seismic, geometric seismic attributes