Modeling breakage and motion of black pepper seeds in cryogenic mill

The present investigation aims to represent three-dimensional motion and breakage phenomena of black pepper seeds in the cryogenic mill (hammer mill) using discrete element method (DEM). In DEM modeling, bonded particle model was coupled with Hertz-Mindlin contact model. Calibration method was used to select appropriate model (bond) parameters. The calibrated set of bond parameters includes 3.12?×?10¹¹?Pa?m^?1 normal stiffness; 1.56?×?10¹¹?Pa?m^?1 shear stiffness; 3.88?×?10⁸?Pa critical normal stiffness; 1.94?×?10⁸?Pa critical shear stiffness. Besides, the validity of calibrated parameters was tested in the hammer mill. The observed qualitative and quantitative results (breakage and flow pattern) of numerical and experimental approaches were in good agreement. Based on these results, a few prefatory suggestions were provided to improve the design aspects of the mill. Overall, DEM modeling offered a better understanding of particle breakage and flow pattern in the mill.     

Laser-Induced Graphene for Electrothermally Controlled,Mechanically Guided, 3D Assembly and Human–Soft Actuators Interaction

Mechanically guided, 3D assembly has attracted broad interests, owing to its compatibility with planar fabrication techniques and applicability to a diversity of geometries and length scales. Its further development requires the capability of on-demand reversible shape reconfigurations, desirable for many emerging applications (e.g., responsive metamaterials, soft robotics). Here, the design, fabrication, and modeling of soft electrothermal actuators based on laser-induced graphene (LIG) are reported and their applications in mechanically guided 3D assembly and human–soft actuators interaction are explored. Over 20 complex 3D architectures are fabricated, including reconfigurable structures that can reshape among three distinct geometries. Also, the structures capable of maintaining 3D shapes at room temperature without the need for any actuation are realized by fabricating LIG actuators at an elevated temperature. Finite element analysis can quantitatively capture key aspects that govern electrothermally controlled shape transformations, thereby providing a reliable tool for rapid design optimization. Furthermore, their applications are explored in human–soft actuators interaction, including elastic metamaterials with human gesture-controlled bandgap behaviors and soft robotic fingers which can measure electrocardiogram from humans in an on-demand fashion. Other demonstrations include artificial muscles, which can lift masses that are about 110 times of their weights and biomimetic frog tongues which can prey insects.     

Polaronic Trions at the MoS2/SrTiO3 Interface

The reduced electrical screening in 2D materials provides an ideal platform for realization of exotic quasiparticles, that are robust and whose functionalities can be exploited for future electronic, optoelectronic, and valleytronic applications. Recent examples include an interlayer exciton, where an electron from one layer binds with a hole from another, and a Holstein polaron, formed by an electron dressed by a sea of phonons. Here, a new quasiparticle is reported, “polaronic trion” in a heterostructure of MoS₂/SrTiO₃ (STO). This emerges as the Fröhlich bound state of the trion in the atomically thin monolayer of MoS₂ and the very unique low energy soft phonon mode (≤7 meV, which is temperature and field tunable) in the quantum paraelectric substrate STO, arising below its structural antiferrodistortive (AFD) phase transition temperature. This dressing of the trion with soft phonons manifests in an anomalous temperature dependence of photoluminescence emission leading to a huge enhancement of the trion binding energy (≈70 meV). The soft phonons in STO are sensitive to electric field, which enables field control of the interfacial trion–phonon coupling and resultant polaronic trion binding energy. Polaronic trions could provide a platform to realize quasiparticle‐based tunable optoelectronic applications driven by many body effects.     

Engineering Metal Nanoclusters for Targeted Therapeutics: From Targeting Strategies to Therapeutic Applications

Metal nanoclusters (NCs) have recently attracted great interest in biomedical applications due to their ultrasmall size, good biocompatibility, and unique molecule-like physical and chemical properties. Metal NCs can be rationally designed and integrated with various targeting moieties to achieve unique physicochemical properties and functions. For therapeutic applications, these multifunctional surface-modified NCs can provide distinctive advantages over native metal NCs, such as improved therapeutic effects and reduced side effects. In this review, the design principles of targeting strategies for metal NCs and their composites, including passive and active targeting, and physical and chemical targeting are first discussed. The authors then focus on the recent achievements in the application of metal NCs in targeted therapeutics, including chemotherapy, phototherapy, and radiotherapy. Finally, the authors’ perspectives on the challenges and opportunities of developing metal NCs in targeted therapeutics, further paving their way for potential clinical applications are provided.     

Reverse atom transfer radical polymerization of stearyl methacrylate using 2,2′‐azobisisobutyronitrile as the initiator

The living/controlled radical polymerization of stearyl methacrylate was carried out with a conventional radical initiator (2,2′‐azobisisobutyronitrile) in N,N‐dimethylformamide in the presence of a 2,2′‐bipyridine complex of hexakis(N,N‐dimethylformamide)iron(III) perchlorate. The polymerization mechanism was thought to proceed through a reverse atom transfer radical polymerization. The molecular weights of resulting poly(stearyl methacrylate) increased with conversion, and the resulting molecular weight distributions were quite narrow. The rates of polymerization exhibited first‐order kinetics with respect to the monomer. A probable reaction mechanism for the polymerization system is postulated to explain the observed results. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1236–1245, 2002     

Nanoscale Ⅲ-V on Si-based junctionless tunnel transistor for EHF band applications

A single gate Ⅲ-V junctionless tunnel field effect transistor (SG-JLTFET) has been reported which shows excellent dc characteristics at low power supply operation. This device has a thin uniformly n-type doped channel of GaSb i.e. gallium antimonide which is grown epitaxially over silicon substrate. The DC performance parameters such as I_ON, I_ON/I_OFF, average and point subthreshold slope as well as device parameters for analog applications viz. transconductance g_m, transconductance generation efficiency g_m/I_D, various capacitances and the unity gain frequency f_T are studied using a device simulator. Along with examining its endurance to short channel effects, the performances are also compared with a Silicon Dual Gate Junctionless Tunnel FET (DG-JLTFET). The DC and small signal analog performance reflects that GaSb SG-JLTFET has immense purview for extreme high-frequency and low-power applications.     

Attractor selection in a modulated laser and in the Lorenz circuit

By tuning a control parameter, a chaotic system can either display two or more attractors (generalized multistability) or exhibit an interior crisis, whereby a chaotic attractor suddenly expands to include the region of an unstable orbit (bursting regime).Recently, control of multistability and bursting have been experimentally proved in a modulated class B laser by means of a feedback method. In a bistable regime, the method relies on the knowledge of the frequency components of the two attractors. Near an interior crisis, the method requires retrieval of the unstable orbit colliding with the chaotic attractor.We also show that a suitable parameter modulation is able to control bistability in the Lorenz system. We observe that, for every given modulation frequency, the chaotic attractor is destroyed under a boundary crisis. The threshold control amplitude depends on the control frequency and the location of the operating point in the bistable regime. Beyond the boundary crisis, the system remains in the steady state even if the control is switched off, demonstrating control of bistability.     

A feasibility study of steam-jet refrigeration

In this paper a feasibility study of steam-jet refrigeration is conducted. First and second law analyses as well as the economics of a steam-jet refrigeration system are presented. Thermodynamic parameters investigated include the coefficient of performance (COP), refrigerating effect, condenser heat rejection, motive steam requirements, second law efficiency, and system irreversibility. Economic parameters investigated include equipment costs, space needs, power requirements, and installed and operational costs. © 1998 John Wiley & Sons, Ltd.     

Polymerization of methyl methacrylate by charge-transfer mechanism with 2,2′-bipyridine and iron (III) complex

Polymerization of methyl methacrylate (MMA) by the charge-transfer complex formed by the interaction of 2,2′-bipyridine (bpy), MMA, and carbon tetrachloride (CCl₄) was studied in dimethylsulfoxide (DMSO) at 60°C. The rate of polymerization (R_p) is sensitive to the [CCl₄] at low concentration of CCl₄, but at a higher concentration it is practically independent of [CCl₄]. R_p is proportional to [MMA]^1.45±0.04 and [bpy]^0.52±0.04 when [CCl₄] > [bpy], and the average rate constant, k, at 60°C for the polymerization of MMA was 7.14 ± 0.40 × 10⁻⁶ L mol⁻¹s⁻¹. Kinetic studies showed that the polymerization proceeds through free radical intermediates. This article also reports the polymerization of MMA initiated by bpy and CCl₄ and accelerated by Lewis acid, hexakis (dimethylsulfoxide)iron(III) perchlorate [Fe(DMSO)₆](ClO₄)₃ at 60°C. The glass transition temperature and molecular weights of the samples were investigated by using differential scanning calorimetry and gel permeation chromatography techniques, respectively. Probable reaction mechanisms are proposed to explain the observed results. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2097–2103, 1997