Extraordinary Material Research Articles

Symmetry breaking and effects of nutrient walkway in time-dependent bone remodeling incorporating poroelasticity

Bone is an extraordinary biological material that continuously adapts its hierarchical microstructure to respond to static and dynamic loads for offering optimal mechanical features, in terms of stiffness and toughness, across different scales, from the sub-microscopic constituents within osteons—where the cyclic activity of osteoblasts, osteoclasts, and osteocytes redesigns shape and percentage of mineral crystals and collagen fibers—up to the macroscopic level, with growth and remodeling processes that modify the architecture of both compact and porous bone districts. Despite the intrinsic complexity of the bone mechanobiology, involving coupling phenomena of micro-damage, nutrients supply driven by fluid flowing throughout hierarchical networks, and cells turnover, successful models and numerical algorithms have been presented in the literature to predict, at the macroscale, how bone remodels under mechanical stimuli, a fundamental issue in many medical applications such as optimization of femur prostheses and diagnosis of the risk fracture. Within this framework, one of the most classical strategies employed in the studies is the so-called Stanford’s law, which allows uploading the effect of the time-dependent load-induced stress stimulus into a biomechanical model to guess the bone structure evolution. In the present work, we generalize this approach by introducing the bone poroelasticity, thus incorporating in the model the role of the fluid content that, by driving nutrients and contributing to the removal of wastes of bone tissue cells, synergistically interacts with the classical stress fields to change homeostasis states, local saturation conditions, and reorients the bone density rate, in this way affecting growth and remodeling. Through two paradigmatic example applications, i.e. a cylindrical slice with internal prescribed displacements idealizing a tract of femoral diaphysis pushed out by the pressure exerted by a femur prosthesis and a bone element in a form of a bent beam, it is highlighted that the present model is capable to catch more realistically both the transition between spongy and cortical regions and the expected non-symmetrical evolution of bone tissue density in the medium–long term, unpredictable with the standard approach. A real study case of a femur is also considered at the end in order to show the effectiveness of the proposed remodeling algorithm.

RETRACTED: A Review on Structural Performance of Bamboo Reinforced Concrete

Retracted article: The technique of using small diameter whole-culm and split bamboo has been often suggested as an alternative method for concrete strengthening. Bamboo is widely available in tropical and sub-tropical locations, while the quest for a new sustainable alternative is a new and recent trend in the construction industry. Using bamboo in reinforced concrete is discussed in this paper and it is analysed as a structural and environmental alternative to steel reinforced concrete. Reinforced concrete is widely used in many countries where bamboo reinforced concrete might be used as a design alternative to determine the life cycle of reinforced concrete. However, bamboo was extraordinary material. Therefore, it is used in reinforced concrete due to significant durability and reduced stiffness problem, which positively impacts the environment. Hence, this paper discusses a review on the structural performance of bamboo reinforced concrete based on previous research.

Stimulated Brillouin scattering in a sub-wavelength anisotropic waveguide with slightly-misaligned material and structural axes: misalignment-sensitive behaviors and underlying physics

The stimulated Brillouin scatterings (SBSs) in sub-wavelength rutile waveguides with slightly misaligned material and structural axes are numerically studied. The misalignment is introduced between the extraordinary material axis and longitudinal axis of the waveguide only. Four nanowire waveguides with different cross-sectional geometries are considered. They consist of a circular waveguide, two elliptical waveguides with different cross-sectional orientation angles, and a trapezoidal waveguide with a completely unsymmetrical cross-sectional shape. As previously reported, the resonant peaks emerge rapidly in response to the introduced small misalignment angle and can also be observed in the calculated Brillouin gain spectra of the considered waveguides. But these misalignment-sensitive resonant peaks further exhibit some extraordinary behaviors, which may not be intuitively understandable. For instance, despite a plausible absence of symmetry breaking, many misalignment-sensitive resonant peaks can still be observed in the forward SBS gain spectrum of the trapezoidal waveguide. Based on the symmetry properties of the considered waveguides, the physics underlying the observed extraordinary phenomena are revealed. The obtained results highlight the effectiveness of introducing symmetry breakings for activating/harnessing opto-mechanical couplings in photonic-phononic micro structures, which would enable us to gain some deeper insights into the sub-wavelength opto-mechanics in anisotropic media.

Flowering Plums and Curio Cabinets: The Culture of Objects in Late Chosŏn Korean Art by Sunglim Kim, and: A New Middle Kingdom: Painting and Cultural Politics in Late Chosŏn Korea (1700–1850) by J. P. Park

Reviewed by: Flowering Plums and Curio Cabinets: The Culture of Objects in Late Chosŏn Korean Art by Sunglim Kim, and: A New Middle Kingdom: Painting and Cultural Politics in Late Chosŏn Korea (1700–1850) by J. P. Park Yoonjung Seo Sunglim Kim, Flowering Plums and Curio Cabinets: The Culture of Objects in Late Chosŏn Korean Art (Seattle: Univ. of Seattle Press, 2018). Pp. 304; 80 color illus., 18 b/w illus., 1 map. $65.00 cloth. J. P. Park, A New Middle Kingdom: Painting and Cultural Politics in Late Chosŏn Korea (1700–1850) (Seattle: Univ. of Washington Press, 2018). Pp. 296; 93 color illus. $65.00 cloth. As a field of research, Korean art history is relatively young. It has grown rapidly over the last five decades: ritual, social, and political contexts have been investigated, period styles have been defined, canonical works have been identified, and important subjects and iconography have been discerned. Among scholars of Korean art, however, the nationalistic ideology that Korean art uniquely represents “Korean-ness” remains deeply entrenched, causing aesthetic value and style to be seen as expressions of national spirit and suggesting that the cultural essence of Korean art remains unchanged throughout history. This tendency has left little room for modernist or postmodernist theory, argumentation, questioning of social contexts, or consideration of a more nuanced role for Korea in East Asia. Sunglim Kim’s Flowering Plums and Curio Cabinets and J.P. Park’s A New Middle Kingdom are timely and valuable contributions to our understanding of the complex problems that Korean art historians have faced for decades. The authors tackle the issues of social class, the art market, nationalism, and cultural identity in the visual and material culture of the eighteenth-century Chosŏn dynasty, an era marked by economic and cultural efflorescence. Drawing on a wide range of theoretical perspectives, both authors offer insightful analyses of paintings along with examination of literary sources such as contemporaneous poems, diaries, letters, correspondence, and travel accounts. Sunglim Kim’s Flowering Plums and Curio Cabinets investigates the roles of the chungin, an upper-middle-class group of lesser bureaucrats and well-educated technical specialists, in the development of the art market and material culture of the late Chosŏn period (1700–1910). Kim calls into question “the traditional binary system” that categorizes Korean artists as either amateur literati or professional court painters and overlooks the existence of the chungin (7). Underscoring the role of the chungin as creators and consumers of artwork and as connoisseurs and tastemakers, Kim explores two related subjects—ch’aekkŏri screens and flowering plum paintings. Kim’s stylistic analysis and iconographical research shed light on chungin artists’ innovation of new subjects and styles as well as their commercial stimulation of late Chosŏn art. The first chapter opens with the chungins’ attempts to form a collective identity through cultural activities, including creating poetry societies, collecting art, pursuing painting and calligraphy, and acting as connoisseurs, dealers, and patrons, activities pursued with the goal of creating new genres as self-expression and a new group identity. Countering long-standing assumptions of a rigid unilateral relationship between the ruling yangban aristocrats and the secondary chungin class, Kim offers a complex reading of these groups’ relationships as exemplified by the careers of Kim Chŏnghŭi (1768–1856), the eminent yangban scholar artist, and Yi Sangjŏk (1804–1865), a Chinese-Korean chungin interpreter. According to Kim, [End Page 395] their relationship was not simply that of “yangban-teacher and chungin-follower” but rather “a fluid association, mutually dependent and beneficial with reciprocal exchanges of material, services, and artistic and monetary rewards” (41). Chapter 2 turns to ch’aekkŏri screens, opening with description of their role as a reflection of their owner’s social status, knowledge, wealth, and cultural sophistication. Ch’aekkŏri screens’ representation of still lives with books made them a genre newly invented by chungin painters, one that in Kim’s view bespeaks their owners’ attachment to “material culture and self-expression through peculiar obsessions” (29). The extraordinary material culture, avid cultural and artistic expression, and innovative artistic experimentation with European painting techniques that are reflected in ch...

Optical thermometry based on europium doped self-activated dual-emitting LiCa3ZnV3O12 phosphor

In this study, rare-earth-doped self-activated LiCa3ZnV3O12 (LCZV) vanadate phosphors were preparation by a high-temperature solid-state reaction. Their crystal structure, non-contact temperature sensing, and luminescence properties were studied deeply. Excited by ultraviolet light at 340 nm, the emission of [VO4]3− group and the Eu3+ ions were monitored. The highest strength emission peaks at 470 nm and 610 nm for [VO4]3− and Eu3+, respectively, provide favorable signal identification for estimating temperature. Due to thermal quenching behavior and energy transfer, the FIR (Fluorescence Intensity Ratio) from Eu3+ to [VO4]3− exhibits excellent sensitivity performance at 303 K − 523 K. In the meantime, the maximum absolute and relative sensitivities of the obtained phosphors are 0.0068 K−1 and 1.18 % K−1, which are overtopped to those reported previously. Furthermore, for the luminescent color of the CIE diagram with a strong temperature effect, the color coordinate could be verified from (0.2871, 0.3416) to (0.4121, 0.3420), which was matched well with the linear equation. Consequently, the Eu3+ doped LCZV phosphor not only can be used for high-temperature environmental safety signals but also is an extraordinary viable material in the field of optical sensing.

Ion Microprobe Study of the Polarization Quenching Techniques in Single Crystal Diamond Radiation Detectors.

Synthetic single crystal diamond grown using the chemical vapor deposition technique constitutes an extraordinary candidate material for monitoring radiation in extreme environments. However, under certain conditions, a progressive creation of space charge regions within the crystal can lead to the deterioration of charge collection efficiency. This phenomenon is called polarization and represents one of the major drawbacks associated with using this type of device. In this study, we explore different techniques to mitigate the degradation of signal due to polarization. For this purpose, two different diamond detectors are characterized by the ion beam-induced charge technique using a nuclear microprobe, which utilizes MeV energy ions of different penetration depths to probe charge transport in the detectors. The effect of polarization is analyzed by turning off the bias applied to the detector during continuous or discontinuous irradiation, and also by alternating bias polarity. In addition, the beneficial influence of temperature for reducing the effect of polarization is also observed. Finally, the effect of illuminating the detector with light is also measured. Our experimental results indicate that heating a detector or turning off the bias, and then applying it during continuous irradiation can be used as satisfactory methods for recovering the CCE value close to that of a prepolarized state. In damaged regions, illumination with white light can be used as a standard method to suppress the strength of polarization induced by holes.

Żelazo meteorytowe w starożytnym Egipcie przed okresem późnym

The aim of the article is to present an unusual raw material, which is the meteorite iron and its specific status in the culture of ancient Egypt. The presentation of this extraordinary material, highlighting the features allowing to recognize it, the interpretation of the artifacts made of it (taking into account the physicochemical analyzes), and the development of the results of experimental works recreating the methods of its processing allow us to obtain the necessary information about the delineation of meteorite iron metallurgy in ancient Egypt up to the beginning of the Late Period. An important source for achieving the article’s goal are also texts. Text analysis highlights the ambiguity of the terminology used to describe meteorite iron. By reviewing the contexts of its use, they allow us to enrich knowledge about its metallurgy and help to characterize the status of this metal in the consciousness of the Egyptians.

Dual-Phase Nanocomposite TiB2/MoS1.7B0.3: An Excellent Ultralow Friction and Ultralow Wear Self-Lubricating Material.

Proper lubrication is essential to the reliable and efficient operation of mechanical systems ranging from the industrial to the nanoscale. Self-lubricating materials that can self-generate and sustain concurrent ultralow friction and ultralow wear in harsh environments open up a unique realm that is unattainable by traditional external lubrication mechanisms, but developing such extraordinary materials has been a long-standing grand challenge. Here, we devise an unconventional strategy to construct a dual-phase nanocomposite (DPNC) that comprises a wear-resistant phase (TiB2) and an internal lubricant source (MoS1.7B0.3). Tribological tests demonstrate simultaneous ultralow friction coefficient (∼0.03) and ultralow wear rate (∼10-10 mm3·N-1·m-1) of the synthesized DPNC specimen in ambient environments; these superb properties remain intact after the specimen has been annealed at 400 °C in air. First-principles energetic and stress-strain calculations elucidate atomistic mechanisms underpinning DPNC TiB2/MoS1.7B0.3 as an ultimate self-lubricating material. This accomplishment solves the classic lubricity-durability tradeoff dilemma, enabling advances to meet the most challenging lubrication needs.

Effect of Pristine Graphene on Methylammonium Lead Iodide Films and Implications on Solar Cell Performance

The relatively low stability of solar cells based on hybrid halide perovskites is the main issue to be solved for the implementation in real life of these extraordinary materials. Degradation is accelerated by temperature, moisture, oxygen, and light and mediated by halide easy hopping. The approach here is to incorporate pristine graphene, which is hydrophobic and impermeable to gases and likely limits ionic diffusion while maintaining adequate electronic conductivity. Low concentrations of few-layer graphene platelets (up to 24 × 10–3 wt %) were incorporated to MAPbI3 films for a detailed structural, optical, and transport study whose results are then used to fabricate solar cells with graphene-doped active layers. The lowest graphene content delays the degradation of films with time and light irradiation and leads to enhanced photovoltaic performance and stability of the solar cells, with relative improvement over devices without graphene of 15% in the power conversion efficiency, PCE. A higher graphene content further stabilizes the perovskite films but is detrimental for in-operation devices. A trade-off between the possible sealing effect of the perovskite grains by graphene, that limits ionic diffusion, and the reduction of the crystalline domain size that reduces electronic transport, and, especially, the detected increase of film porosity, that facilitates the access to atmospheric gases, is proposed to be at the origin of the observed trends. This work demonstrated how the synergy between these materials can help to develop cost-effective routes to overcome the stability barrier of metal halide perovskites, introducing active layer design strategies that allow commercialization to take off.

A modest method of synthesis Cu- based metal-organic frameworks using benzene dicarbocxylate as a ligan for promising candidate of flue gas CO2 adsorption

Metal organic framework (MOF) is one of extraordinary materials in many technical field applications. One of them is as CO2 gas adsorbent. We studied, synthesized, and characterized Copper-based material, known as Metal organic frameworks (MOFs), using a solvothermal-based modification method. Copper salt (Cu (NO3)2. 3H2O) and benzene dicarboxylic acid (H2BDC) were mixed and then heated in an oven at 120°C, to produce low impurities, small pore and uniform particle size of materials called CuBDC. Infrared spectroscopy and XRD data confirmed the formation of CuBDC. Furthermore, the result showed that CuBDC frameworks have good thermal stability up to 330°C. Thereafter SEM picture showed random, layered, and asymmetrical corners structure which is typical of triclinic crystal system. Lastly, specific surface areas and the porosity were analyzed using The Brunauer-Emmett-Teller (BET) method. It recorded 485 m2.g-1 of surface area while average pore volume and average pore size are 0.16 cm3.g-1 and 5.9 Å respectively. @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-536869121 1107305727 33554432 0 415 0;}p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin:0cm; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman",serif; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-US;}.MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-size:10.0pt; mso-ansi-font-size:10.0pt; mso-bidi-font-size:10.0pt; mso-ansi-language:IN; mso-fareast-language:IN;}div.WordSection1 {page:WordSection1;}

Designing Artificial Vibration Modes of Piezoelectric Devices Using Programmable, 3D Ordered Structure with Piezoceramic Strain Units

Piezoelectric ceramic devices, which utilize multifarious vibration modes to realize electromechanical coupling and energy conversions, are extensively used in high-technological fields. However, the excitation of basic modes is mainly subjected to natural eigenfrequency of ceramic devices, which is related to the structure and material parameters. Herein, inspired by metamaterial theory, a programmable, 3D ordered structure with piezoceramic strain units (3D OSPSU) is developed to artificially generate basic modes in a broad frequency band other than only in narrow eigenfrequency. A (2 × 2 × 2) arrayed, co-fired, multilayer 3D OSPSU is painstakingly designed and fabricated for generating basic modes, such as flexural, extension, shear, torsion, and even coupled modes at nonresonance. To validate the 3D OSPSU method, a five-degree-of-freedom micro-nano actuating platform based on only one co-fired multilayer ceramic is constructed. The proposed methodology provides a new paradigm for creating extraordinary material properties of piezoelectric ceramics and will inspire brand-new piezoelectric device designs.

Precise Regulation of Ga-Based Liquid Metal Oxidation

ConspectusLiquid metals, defined as metals or alloys with melting points below or near room temperature, can be regarded as an amorphous solid without any crystallinity in the molten state, exhibiting fundamentally different fluidities and metallicities from solid metals and other liquids. In the past decade, gallium as a typical representative liquid metal with a melting point of ∼29.8 °C, virtually nonexistent vapor pressure, and negligible toxicity has been proposed as a base material for the construction of gallium (Ga)-based liquid metals (LMs). This class of extraordinary materials with unique physicochemical properties, such as superb thermal and electrical conductivity, fluidity, shape transformability, self-healing capability and biocompatibility, biodegradability, catalytic properties, plasmonic effect, and facile functionalization accessibility, has attracted considerable attention in widespread applications. Generally, under the action of ambient oxygen and water, the ultrathin oxide layers will be formed at the LM–ambient environment interface, which may provide a physical, chemical, and electrical barrier to prevent the LMs from further oxidation. The introduction of excitations, such as electrical, chemical, electrochemical, mechanical, and ultrasonic, and the alteration of reaction conditions including ingredients, temperature, and time will promote oxide formation. However, the existence of oxides is a double-edged sword, sometimes considered as a nuisance because of the deterioration of performance and stability; for example, the oxides will adhere to the system, which brings problems for fluidic applications (such as heat-transfer media, pump media, and microfluidity). Conversely, in some cases, oxides are considered essential to improve functionality, such as shape transformation, substrate adhesion, intracellular uptake, etc. For this reason, the main aim of oxidation regulation is to alter the fundamental physicochemical properties or even endow distinct and fascinating properties for the LMs, thereby expanding the scope of applications. Although technological advances have shown dramatic progress and great potential of the LMs, their oxidation regulation remains in its infancy, thus deserving further attention. In this Account, we present a relatively elaborate summary of the oxidation regulation of LMs. First, the fundamental properties of LM oxides and their performance impact on LMs are reviewed. Then, the visions expanding to precise oxidation regulation in terms of vital structural statuses of LMs. After that, representative applications focusing on our own contributions to this field in recent years are described. Finally, brief perspectives and challenges are also presented here. Overall, this Account not only sheds light on the valuable balance between pristine LMs and oxides but also proposes prospective principles for the design and synthesis of advanced LM materials with tunable or even unprecedented properties.

Effects of gallium and arsenic substitution on the electronic and magnetic properties of monolayer SnS

Monolayer tin sulphide (SnS) is an extraordinary two-dimensional material with semiconductor nature. We have explored the doping effects of Gallium (Ga) and Arsenic (As) atoms on the electronic and magnetic properties of monolayer SnS using first-principles calculations. We find that the doped system are energetically stable due to high binding energies. Both the dopants retain the semiconductor nature of monolayer SnS with a tuneable band gap. Interestingly, spin-polarization with magnetic moment of 1.00 μ B has been induced in both Ga- and As-doped monolayer SnS. Moreover, the realization of magnetic anisotropy energy (MAE) could pave a way to utilize Ga- and As-doped monolayer SnS for applications in magnetic semiconductor devices.

Constructing anatase TiO2/Amorphous Nb2O5 heterostructures to enhance photocatalytic degradation of acetaminophen and nitrogen oxide

TiO2 nanostructures have been one of the most explored metal oxides photocatalysts to apply for environmental remediation. However, its wide band gap results in the underutilization of sunlight for degradation of pollutants. In order to overcome this handicap, the synthesis of TiO2-based composite has brought extraordinary materials. In this study, we design and prepare TiO2/Nb2O5 heterostructures with different molar ratios by using peroxotitanium and peroxoniobium complex as precursors in aqueous solution. The TiO2 exists in the form of anatase while Nb2O5 is amorphous in the composite, leading to a special crystalline TiO2/amorphous Nb2O5 heterostructures. In particular, Nb element is also doped and Ti3+ ions are formed in the TiO2 lattice, leading to a reduced band gap. The unique TiO2/0.25Nb2O5 (Ti:Nb = 2:1) heterostructures can effectively suppress the recombination of photogenerated electrons and holes, and facilitate the charge transfer, resulting in the optimum photocatalytic performance. The nitrogen oxide removal efficiency by TiO2/0.25Nb2O5 is 77.23% in visible light, which is 3.8-folds and 7.0-folds higher than pure TiO2 and Nb2O5. Photocatalytic degradation of acetaminophen by TiO2/0.25Nb2O5 is 90.6% in visible light, which is approximately 2.5-folds higher than pure TiO2 and Nb2O5.

C36 and C35E (E=N and B) Fullerenes as Potential Nanovehicles for Neuroprotective Drugs: A Comparative DFT Study

AbstractDoped fullerenes are extraordinary materials with unique electronic and optical properties, which also show potential for diverse biomedical applications. Employing density functional theory (DFT) and time‐dependent density functional theory (TD‐DFT) calculations; we studied the propensity of C36 and C35E (E=N and B) fullerenes as potential nanovehicles for certain neuroprotective drugs that are efficacious for Parkinson's disease. Baclofen, modafinil, rasagiline and rivastigmine were systematically studied to analyze whether they could be carried by small fullerenes. C36 and C35N fullerenes represent promising nanostructure candidates, due to their adsorption energy (physisorption) and favorable electrostatic interaction for the molecular transport of baclofen and rivastigmine drugs. Furthermore, in order to evaluate the effect of temperature on these interactions, ab initio molecular dynamics (AIMD) were also performed. The results from this work are expected to motivate additional investigations concerning these systems, using both theoretical and experimental approaches, in order to demonstrate their versatility as novel carbon‐based nanovehicles.

Silica aerogels; a review of synthesis, applications and fabrication of hybrid composites

Silica aerogels are gaining significant importance and have attracted considerable interest due to their extraordinary properties and numerous applications. Silica aerogels are highly porous with high surface area and very low density and thermal conductivity. Usually they are prepared and synthesized via sol-gel technique, which involves making a sol containing a precursor, a solvent and a catalyst. The properties possessed by the final product depend upon numerous factors such as ratio of precursor to solvent and the drying method employed. Due to the flexibility of synthesis methods and the production of aerogels with tailored properties, silica aerogels have found numerous commercial applications and are being investigated of their suitability in several areas, such biomedical and aerospace engineering. Despite having exceptional properties, silica aerogels come with drawbacks such as brittleness and low mechanical strength, which can be resolved by fabricating composites extending the potential applications. This paper reviews the synthesis of silica aerogels via sol-gel technique, and the applications where this extraordinary material has shown promising results. The different materials used for the fabrication of composites to improve and enhance the physical and chemical properties of silica aerogels are also presented.

Modified screen-printed electrode using graphene ink for electrochemical sensor application

In lab-on-chip development, screen printed electrode (SPE) method is usually utilized as an electrochemical sensor. As a basic conductive material, carbon has several advantages compared to other conductive materials. SPE performance can be enhanced by using a nanomaterial due to its unique properties, such as its small size particle and large surface area that can accelerate the electron transfer on the surface of the electrode. Graphene as a carbon-based nanomaterial is an extraordinary material to work with because of its good electrical conductivity and large specific surface area. In this work, we developed a graphene paste from the water-based graphene ink with the addition of polyurethane binder material to realize a nanocarbon conductive paste, which insoluble in water and other electrolytes. Our graphene paste was deposited on the working electrode area of SPE and the performance was tested using cyclic voltammetry method. The result showed that the optimal ratio for the graphene carbon paste, polyurethane to graphene ink, was 1:15 %vol. With this ratio, the performance of the modified SPE could successfully be increased and it also showed a stable sensing performance by having a low error value, below 3%, for 7 times of repeated measurements.

Comparative analysis of chatter in micro end milling operations

The advancement in microfabrication in pursuit of miniaturization is cutting a dynamic role for micro-milling. Micro-milling is a fast and cost-efficient threedimensional fabrication method with the ability to achieve good accuracy, low surface roughness and extraordinary material removal rate (MRR) compared to some other micro manufacturing processes. Given the need for components with high dimensional integrity, identification of appropriate machining conditions is very vital to getting good surface finish. It is also required to couple different complex dynamics which are associated with this machining technique. Chatter during milling and micro-milling process bring adverse effects in surface quality, dimensional accuracy and in tool life. There is need for versatile modelling of micro end-milling dynamics in order to understand how chatter affects the micro end milling operation and to advance the synthetic application of several chatter stability parameters to overcome the limitation imposed by the single chatter stability criterion. This study performs a linear and non-linear analysis of chatter in micro end milling based on the major influential parameters. In addition, a detailed time domain simulation for micro end milling was performed to predict the force a displacement resulting from variable cutter geometries. This dynamic simulation results have significant impact on the actual micro milling process towards the manufacturing of miniaturized parts.

Two-dimensional intrinsic ferrovalley GdI2 with large valley polarization

Manipulation of the valley degree of freedom provides a novel paradigm in quantum information technology. In this work, through first principles calculations, we demonstrate that monolayer $\mathrm{Gd}{\mathrm{I}}_{2}$ is a promising candidate material for valleytronic applications. Monolayer $\mathrm{Gd}{\mathrm{I}}_{2}$ can be easily exfoliated from bulk, and it is spontaneously valley polarized with a giant splitting of 149 meV due to its intrinsic ferromagnetism and large spin orbital coupling. The anomalous valley Hall effect could be realized in monolayer $\mathrm{Gd}{\mathrm{I}}_{2}$ by an appropriate external electric field. Furthermore, the valley polarization feature is stable against the biaxial in-plane strain. Our findings provide an extraordinary and potential material platform for experimental studies and practical applications in the emergent field of valleytronics.

Structure Prototype Outperforming MXenes in Stability and Performance in Metal‐Ion Batteries: A High Throughput Study

AbstractWhile the MXene Ti3C2 is well known for its extraordinary material properties with wide applications, it is demonstrated here that it is not the most stable 2D titanium carbide. Evolutionary search and first‐principles calculations are employed to predict for Ti3C3 a novel structure prototype with P4/mmm symmetry and tetragonal sandwich structure. The cohesive energy, phonon dispersion, and melting point demonstrate high stability of Ti3C3. The mechanical properties are found to be even better than those of graphene in terms of Young's modulus and fracture strength. The metallicity of Ti3C3 indicates potential in metal‐ion batteries. The diffusion barriers for Li, Na, K, and Ca atoms are found to be as low as 0.15, 0.04, 0.002 (record among the known 2D materials), and 0.14 eV, respectively, suggesting the possibility to realize fast charge and discharge. Importantly, the discovered structure prototype gives rise to a whole family of 2D materials. For example, six thermally and dynamically stable materials with metallic properties, Ti3X3 (X = B, Si, Ge, N, P, and As) are identified. The family is promising not only in the fields of nano‐mechanics and metal‐ion batteries but also can guide the search for further 2D structure prototypes.