1,016 research outputs found
Molecular-dynamics simulations of stacking-fault-induced dislocation annihilation in pre-strained ultrathin single-crystalline copper films
We report results of large-scale molecular-dynamics (MD) simulations of
dynamic deformation under biaxial tensile strain of pre-strained
single-crystalline nanometer-scale-thick face-centered cubic (fcc) copper
films. Our results show that stacking faults, which are abundantly present in
fcc metals, may play a significant role in the dissociation, cross-slip, and
eventual annihilation of dislocations in small-volume structures of fcc metals.
The underlying mechanisms are mediated by interactions within and between
extended dislocations that lead to annihilation of Shockley partial
dislocations or formation of perfect dislocations. Our findings demonstrate
dislocation starvation in small-volume structures with ultra-thin film
geometry, governed by a mechanism other than dislocation escape to free
surfaces, and underline the significant role of geometry in determining the
mechanical response of metallic small-volume structures.Comment: 28 pages, 3 figure
Transition from a Tomonaga-Luttinger liquid to a Fermi liquid in potassium intercalated bundles of single wall carbon nanotubes
We report on the first direct observation of a transition from a
Tomonaga-Luttinger liquid to a Fermi liquid behavior in potassium intercalated
mats of single wall carbon nanotubes (SWCNT). Using high resolution
photoemission spectroscopy an analysis of the spectral shape near the Fermi
level reveals a Tomonaga-Luttinger liquid power law scaling in the density of
states for the pristine sample and for low dopant concentration. As soon as the
doping is high enough to fill bands of the semiconducting tubes a distinct
transition to a bundle of only metallic SWCNT with a scaling behavior of a
normal Fermi liquid occurs. This can be explained by a strong screening of the
Coulomb interaction between charge carriers and/or an increased hopping matrix
element between the tubes.Comment: 5 pages, 4 figure
A Simple, Rapid and Efficient One-pot Protocol for the Synthesis of 2-substituted Benzothiazole Derivatives and their Antimicrobial Screening
A rapid and efficient condensation reaction of 2-aminothiophenol with various fatty acids in solvent-free conditions with or without microwave irradiation was carried out to afford the corresponding 2-substituted benzothiazole derivatives in good to excellent yields. The structures of the new products were established by elemental analyses, IR, 1H NMR, 13C NMR and mass spectral data. All the title compounds were screened for their antibacterial and antifungal activity. Most of the compounds exhibited good antimicrobial activity.Keywords: Fatty acids, 2-substituted benzothiazole, 2-aminothiophenol, antimicrobial activity, microwave irradiatio
Electroadhesive Auxetics as Programmable Layer Jamming Skins for Formable Crust Shape Displays
Shape displays are a class of haptic devices that enable whole-hand haptic
exploration of 3D surfaces. However, their scalability is limited by the
mechanical complexity and high cost of traditional actuator arrays. In this
paper, we propose using electroadhesive auxetic skins as a strain-limiting
layer to create programmable shape change in a continuous ("formable crust")
shape display. Auxetic skins are manufactured as flexible printed circuit
boards with dielectric-laminated electrodes on each auxetic unit cell (AUC),
using monolithic fabrication to lower cost and assembly time. By layering
multiple sheets and applying a voltage between electrodes on subsequent layers,
electroadhesion locks individual AUCs, achieving a maximum in-plane stiffness
variation of 7.6x with a power consumption of 50 uW/AUC. We first characterize
an individual AUC and compare results to a kinematic model. We then validate
the ability of a 5x5 AUC array to actively modify its own axial and transverse
stiffness. Finally, we demonstrate this array in a continuous shape display as
a strain-limiting skin to programmatically modulate the shape output of an
inflatable LDPE pouch. Integrating electroadhesion with auxetics enables new
capabilities for scalable, low-profile, and low-power control of flexible
robotic systems.Comment: Accepted to IEEE International Conference on Robotics and Automation
(ICRA 2023
The Effect of Fish Size and Condition on the Contents of Twelve Essential and Non Essential Elements in Aristichthys nobilis
The correlation coefficients between fish size (body weight and total length) and metal contents (Na, K, Ca, Mg, Mn, Fe, Cu, Zn, Cr, Co, Cd and Pb) in whole fish (Aristichthys nobilis) were determined. A total of 71 fish samples were collected from hatcheries and fish reservoirs located in Islamabad and Fatehjung. Highly significant (P<0.001) relationship between metal concentrations and fish size was found. Most of the metals (Na, K, Ca, Mg, Cu, Zn, Cr, Cd and Pb) showed an isometric increase, while Mn, Fe and Co showed an allometric increase in with increasing body weight. All metals showed isometric increase, while, Na, Mn, Fe, Cu, and Co showed positive allometric growth in relation to total length. The correlation coefficient (r) between different variables and wet body weight, condition factor was found highly significant (P<0.001) in examined fish except for Na, Ca, Cu, Zn, Cd and Pb while for total length the same results found except Ca, Cd, Zn and Pb. Variance inflation factor values of regression coefficients in multiple regression analysis for each variable were lesser than 10. The metal levels of the examined fish were lower than the recommended values in fish and fishery products set by FAO
Recreation Center Di Manado (Culture and Art Edutainment)
Kota Manado merupakan ibu kota dari provinsi Sulawesi Utara pada saat ini memiiiki visi menjadi kota pariwisata dunia dengan mengandalkan potensi sumber daya alamnya. Dengan adanya program ini maka pemerintah melakukan peningkatan pembangunan di bidang pariwisata sehingga bidang pariwisata menjadi salah satu andalan perekonomian kota Manado. Tentunya hal ini membuat pembangunan di kota Manado meningkat dengan pesat, khususnya rekreasi. Apalagi dengan budaya yang berkembang pada masyarakat Manado yaitu bersenang-senang dan suka mencari rekreasi dan hiburan. Tempat rekreasi yang ada sekarang masih kurang memfasilitasi seluruh kegiatan rekreasi, karena lokasinya yang masih terpencar-pencar. Mengingat tempat-tempat bisnis rekreasi atau recreation yang ada diprediksi akan meningkat sangat tinggi, sehingga upaya pemberadaan tempat rekreasi menjadi perhatian utama. Peluang bisnis dalam bidang recreation ini perlu diantisipasi dengan menghadirkan wadah yang khusus bergerak dalam bidang pelayanan jasa rekreasi atau recreation yang terlokalisasi dalam satu kawasan dengan fasilitas-fasilitas pelayanan dan penunjang yang cukup lengkap sehingga dapat memudahkan konsumen untuk mendapatkan yang mereka butuhkan dalam satu tempat saja.Hal ini mendasari munculnya sebuah gagasan untuk merancang suatu recreation center (pusat rekreasi) di Manado yang dapat menjadi sarana rekreasi, tempat bersenang-senang sekaligus tempat bersosialisasi bagi masyarakat Manado
Functional outcomes of conservatively treated clavicle fractures
OBJECTIVE: The main aim of the study was to analyze the outcomes of clavicle fractures in adults treated non-surgically and to evaluate the clinical effects of displacement, fracture patterns, fracture location, fracture comminution, shortening and fracture union on shoulder function. METHODS: Seventy clavicle fractures were non-surgically treated in the Orthopedics Department at the Tuanku Ja'afar General Hospital, a tertiary care hospital in Seremban, Malaysia, an average of six months after injury. The clavicle fractures were treated conservatively with an arm sling and a figure-eight splint for three weeks. No attempt was made to reduce displaced fractures, and the patients were allowed immediate free-shoulder mobilization, as tolerated. They were prospectively evaluated clinically and radiographically. Shoulder function was evaluated using the Constant scoring technique. RESULTS: There were statistically significant functional outcome impairments in non-surgically treated clavicle fractures that correlated with the fracture type (comminution), the fracture displacement (21 mm or more), shortening (15 mm or more) and the fracture union (malunion). CONCLUSION: This article reveals the need for surgical intervention to treat clavicle fractures and improve shoulder functional outcomes
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