Design Recipe Research Articles

Machine Learning-Enabled Superior Energy Storage in Ferroelectric Films with a Slush-Like Polar State.

Heterogeneities in structure and polarization have been employed to enhance the energy storage properties of ferroelectric films. The presence of nonpolar phases, however, weakens the net polarization. Here, we achieve a slush-like polar state with fine domains of different ferroelectric polar phases by narrowing the large combinatorial space of likely candidates using machine learning methods. The formation of the slush-like polar state at the nanoscale in cation-doped BaTiO3 films is simulated by phase field simulation and confirmed by aberration-corrected scanning transmission electron microscopy. The large polarization and the delayed polarization saturation lead to greatly enhanced energy density of 80 J/cm3 and transfer efficiency of 85% over a wide temperature range. Such a data-driven design recipe for a slush-like polar state is generally applicable to quickly optimize functionalities of ferroelectric materials.

Concurrent Shape Optimization of the Part and Scanning Path for Powder Bed Fusion Additive Manufacturing

This paper investigates the concurrent path planning optimization and the built part structural optimization for powder bed fusion additive manufacturing processes. The state of the art studies rely on existing patterns for trajectories for a fixed built shape. The shape is often optimized for its mechanical performance but rarely in a combined way with its path planning building process. In this work, a two-dimensional model (in the layer plane) of the process is proposed under a steady state assumption. Then a systematic path optimization approach, free from a priori restrictions and previously developed in [M. Boissier, G. Allaire, and C. Tournier [Struct. Multidiscip. Optim., 61 (2020), pp. 2437–2466], is coupled to a structural optimization tool, both of them based on shape optimization theory. This multiphysics optimization leads to innovative and promising results. First, they confirm that it is essential to take into account the part shape in the scanning path optimization. Second, they also give hints to some design recipes: the material and the source parameters must be related to the thickness of the bars that compose the structure. Indeed, the thickness of a bar is a key ingredient which determines the type of path pattern to scan it: straight line, Omega-pattern, and Wave-pattern.

Topology-optimized thermal metamaterials traversing full-parameter anisotropic space

It is widely adopted in thermal metamaterials that mixing different materials could conveniently result in effective thermal conductivities (ETCs) beyond naturally-occurring materials. When multiple materials are isotropically mixed, the ETC is a direct average governed by their filling fractions and given bulk conductivities. That could lead to an inhomogeneous and anisotropic value within the maximal and minimal thermal conductivities of constituent materials. Usually thermal metadevices rely on anisotropic thermal conductivity tensor, whose tensorial elements are frequently inter-dependent and confined within a limited parametric space. It is thus nontrivial to establish a design recipe for advanced thermal metamaterials whose ETCs could cover full-parameter anisotropic space. We demonstrate topological functional cells (TFCs) with copper and polydimethylsiloxane, and show that the anisotropic ETCs traverse their full-parameter space. Such robust scheme based on topology-optimized TFCs unlocks unexplored opportunities for functional thermal metadevices whose parameters may not be reached in previous mixing approaches. This study also sheds light on the developments in emerging acoustic, mechanical and electromagnetic composite materials.

Relative-phase simulated annealing for time-efficient and large-scale inverse design of achromatic thin lenses.

High-efficiency, broadband, wafer-size, and ultra-thin lenses are highly demanded, due to its great potential in abundant applications such as compact imaging modules. It is usually conceived that this target might be attainable given the advancement in nanofabrication, computation power and emerging algorithms, though challenging. Here, we reveal the inconvenient truth that for ultra-thin lenses, there actually exists intrinsic check-and-balance between size, broadband and performance. Unveiled by our inverse design algorithm, Relative-Phase Simulated Annealing (RPSA), focusing efficiency inevitably drops with refining wavelength intervals for better achromatic broadband features in optimized lens; and drops exponentially with increasing diameter and bandwidth, supported by our empirical formula. Meanwhile, with a slightly compromised goal, the powerfulness of RPSA is unlocked since it could provide a globally optimized design recipe whose time complexity relates to lens scale linearly rather than exponentially. This work, as a fast search engine for optimal solutions, paves the way towards practical large-scale achromatic ultra-thin lenses.

Miniature β-Hairpin Mimetic by Intramolecular Hydrogen Bond and C–H···π Interactions

Canonically, protein β-hairpin motifs are stabilized by intramolecular hydrogen bonds. Here, we attempt to develop a rational design recipe for a miniature hairpin structure stabilized by hydrogen bonding as well as C–H···π interaction and try to understand how such a stabilization effect varies with different functional groups at each terminus. Database analysis shows that the α-amino acids with an aromatic side chain will not favor that kind of C–H···π stabilized hairpin structure. However, hybrid tripeptides with an N-terminal Boc-Trp-Aib corner residue and C-terminal aromatic ω-amino acids fold into the hairpin conformation with a central β-turn/open-turn that is reinforced by a C–H···π interaction. The CCDC database analysis further confirms that this C–H···π stabilized hairpin motif is general for Boc-protected tripeptides containing Aib in the middle and aromatic functionality at the C-terminus. The different α-amino acids like Leu/Ala/Phe/Pro/Ser at the N-terminus have a minor influence on the C–H···π interaction and stabilities of the folded structures in solid-state. However, the hybrid peptides exhibit different degrees of conformational heterogeneity both in the solid and solution phase, which is common for this kind of flexible small molecule. Conformational heterogeneity in the solution phase including the C–H···π stabilized β-hairpin structures are characterized by the molecular dynamics (MD) simulations explaining their plausible origin at an atomistic level.

Temperature-field history dependence of the elastocaloric effect for a strain glass alloy

• The elastocaloric effect appears in a wide temperature range for a strain glass alloy. • An inverse elastocaloric effect is observed in the strain glass alloy with history of zero-field cooling. • The temperature-history dependence of elastocaloric effect can be attributed to the slow dynamics of strain nanodomains in response to the external stress. The singular change of the order parameter at the first order martensitic transformation (MT) temperature restricts the caloric response to a narrow temperature range. Here the MT is tuned into a sluggish strain glass transition by defect doping and a large elastocaloric effect appears in a wide temperature range. Moreover, an inverse elastocaloric effect is observed in the strain glass alloy with history of zero-field cooling and is attributed to the slow dynamics of the nanodomains in response to the external stress. This study offers a design recipe to expand the temperature range for good elastocaloric effect.

Machine Learning‐Based Optimization of Chiral Photonic Nanostructures: Evolution‐ and Neural Network‐Based Designs

Chiral photonics opens new pathways to manipulate light–matter interactions and tailor the optical response of metasurfaces and ‐materials by nanostructuring nontrivial patterns. Chirality of matter, such as that of molecules, and light, which in the simplest case is given by the handedness of circular polarization, have attracted much attention for applications in chemistry, nanophotonics and optical information processing. The design of chiral photonic structures using two machine learning methods, the evolutionary algorithm, and neural network approach, for rapid and efficient optimization of optical properties for dielectric metasurfaces, is reported. The design recipes obtained for visible light in the range of transition‐metal dichalcogenide exciton resonances show a frequency‐dependent modification in the reflected light's degree of circular polarization, that is represented by the difference between left‐ and right‐circularly polarized intensity. Our results suggest the facile fabrication and characterization of optical nanopatterned reflectors for chirality‐sensitive light–matter coupling scenarios employing tungsten disulfide as possible active material with features such as valley Hall effect and optical valley coherence.

Recipes for diffuse correlation spectroscopy instrument design using commonly utilized hardware based on targets for signal-to-noise ratio and precision.

Over the recent years, a typical implementation of diffuse correlation spectroscopy (DCS) instrumentation has been adapted widely. However, there are no detailed and accepted recipes for designing such instrumentation to meet pre-defined signal-to-noise ratio (SNR) and precision targets. These require specific attention due to the subtleties of the DCS signals. Here, DCS experiments have been performed using liquid tissue simulating phantoms to study the effect of the detected photon count-rate, the number of parallel detection channels and the measurement duration on the precision and SNR to suggest scaling relations to be utilized for device design.

Analysis and design procedure of a mm-Wave Class-E power amplifier

This paper presents a Class-E Power Amplifier (PA) design procedure for operation at mm-Wave frequencies, which accounts for the loss of passive components, ON-resistance (Ron) of the transistor, and its breakdown voltage (VBr). The quality factor of inductors is modeled with equivalent resistors and integrated into time-domain equations for the first time. The proposed procedure is examined for the design of a 24 ​GHz Class-E PA in 130 ​nm CMOS technology and compared with former best-known design recipes in the same technology node. Besides, a simplified design technique is introduced based on Ron-Cout (Cout is the transistor output capacitance) curves of the transistor versus its width, obtained by Harmonic Balance (HB) simulation. By the proposed method, the Figure of Merit (FoM) of the designed PA, including a combination of the output power, efficiency, and maximum drain voltage, is improved significantly (52%) compared to the other procedure outcomes in the literature.

Doubly-Resonant Photonic Crystal Cavities for Efficient Second-Harmonic Generation in III-V Semiconductors.

Second-order nonlinear effects, such as second-harmonic generation, can be strongly enhanced in nanofabricated photonic materials when both fundamental and harmonic frequencies are spatially and temporally confined. Practically designing low-volume and doubly-resonant nanoresonators in conventional semiconductor compounds is challenging owing to their intrinsic refractive index dispersion. In this work we review a recently developed strategy to design doubly-resonant nanocavities with low mode volume and large quality factor via localized defects in a photonic crystal structure. We built on this approach by applying an evolutionary optimization algorithm in connection with Maxwell equations solvers; the proposed design recipe can be applied to any material platform. We explicitly calculated the second-harmonic generation efficiency for doubly-resonant photonic crystal cavity designs in typical III–V semiconductor materials, such as GaN and AlGaAs, while targeting a fundamental harmonic at telecom wavelengths and fully accounting for the tensor nature of the respective nonlinear susceptibilities. These results may stimulate the realization of small footprint photonic nanostructures in leading semiconductor material platforms to achieve unprecedented nonlinear efficiencies.

Tailoring thermal expansion coefficient from positive through zero to negative in the compositional crossover alloy Ti50(Pd40Cr10) by uniaxial tensile stress

The precision control of thermal expansion is of fundamental interest and desirable for applications that require materials to retain their shape at different temperatures. In the present study, we propose that the thermal expansion coefficient can be tuned by uniaxial external stress for a single material embedded with nanoclusters, if the formation, growth or alignment of the nanoclusters depends on the external stress. We demonstrate the idea in a prototype alloy (Ti50(Pd40Cr10)) located at the compositional crossover region between martensite and strain glass in the temperature-composition phase diagram of Ti50(Pd50−xCrx). Its thermal expansion coefficient varies linearly from positive, through zero to negative values with increasing uniaxial tensile stress within 200 K ~ 300 K. The phase field simulations show that the volume fraction of nanoscale martensite variant favored by the external stress increases with stress, producing extra strain and compensating for the contraction of the austenite matrix on cooling. The degree of compensation leads to different thermal expansion coefficients. Such a tunable thermal expansion behavior occurs only in the crossover compositions between martensite and strain glass, providing a design recipe for searching new systems with similar behavior.

Design of optimal wine distillation recipes using multi-criteria decision-making techniques

In this work, dynamic multi-objective optimization and multi-criteria decision making (MCDM) techniques were applied to design recipes for optimal alembic wine distillations. The optimization problem considered eight objectives associated with sensorial quality, food safety, productivity, and efficiency. Through correlation analysis of the optimal solutions, it was possible to reduce the original objectives into four conflicting objectives. Seven MCDM methods were tested to select the best recipes considering five scenarios. In the equal priority scenario, each multi-criterion decision-making algorithm selected different solutions. In scenarios with higher priority for a single objective, most multi-criteria decision-making algorithms selected similar or identical solutions. A well balanced performance was achieved when a high priority was assigned to ethanol recovery. This work´s methodology can be easily adapted to define recipes for the optimal operation of any fruit batch distillation process.

Cathode-Electrolyte Interphase in Lithium Batteries Revealed by Cryogenic Electron Microscopy

Summary Cathode electrolyte interphase (CEI), the intimate coating layer formed on the positive electrode, has been thought to be critical. However, many aspects of CEI remain unclear. This originates from the lack of effective tools to characterize structural and chemical properties of these sensitive interphases at nanoscale. Here, we develop a protocol to preserve the native state and directly visualize the interface on the positive electrode using cryogenic electron microscopy. We find that under normal operation conditions, there does not exist an intimate coating layer at the single-particle level in carbonate-based electrolyte. However, upon brief external electrical shorting, a solid-electrolyte interphase, which usually forms on anodes, could form on cathodes and be electrochemically converted into a stable, conformal CEI in situ. The conformal CEI helps improve Coulombic efficiency and overall capacity retention of the battery. This generates a different perspective of CEI in commercial carbonate-based electrolytes than previously understood.

Prebiotic «Lactulose Premium» as a Promising Functional Additive in Minced Fish

The diet balancing includes various approaches, including a way to expand the culinary products range from minced fish raw materials. To a certain extent, the indispensability and specific value of fish and other aquatic organisms, especially in children’s diets, lies in their therapeutic, prophylactic and dietary orientation, which is caused, first of all, by the balance of their chemical composition (complete protein complexes). Today, fish farms of our country grow carp, crucian, grass carp, white and spotted silver carp, garfish, pike perch, European, African and canal catfish and other types of freshwater fish. Many farms obtain modern workshops for the manufacture of semi-finished fish products: fish fillet, minced meat and other products after shock freezing in vacuum packaging. Considering the protein complexes lack in food and excessive consumption of animal lipids, scientists design recipes of frozen fish-growing composition with functional properties based on fish and vegetable raw materials. This product (for example, in the form of minced meat) becomes in demand at present due to the nutritional value, taste, physiological influence and low cost. All of the above leads to the advisability of obtaining minced fish with the addition of functional powder ingredients, for example, the “Lactulose Premium” prebiotic powder mixture, which includes a valuable component that is not present in fish raw materials, which makes fish products a functional ground minced meat product while maintaining consumer properties of this type of product. Thus, the technologies development for the production of functional minced fish semi-finished product with prebiotic properties and fish culinary dishes based on them is a relevant and promising direction of the food industry development.

How to Design While Loops

Beginning students find the syntactic construct known as a while loop difficult to master. The difficulties revolve around guaranteeing loop termination and around learning how to properly sequence mutations to solve a problem. In fact, both of these are intertwined and students need to be taught a model that helps them reason about how to design while loops. For students that have been introduced to how to design programs using structural recursion, generative recursion, accumulative recursion, and mutation, the task of teaching them how to design while loops is made easier. These students are familiar, for example, with state variables, termination arguments, and accumulator invariants. All of these are fundamental in the design of while loops. This articles presents a novel technique used at Seton Hall University to introduce beginners to the design of while loops. It presents a design recipe that students can follow step-by-step to establish such things as the driver of the loop, the loop invariant, and the proper sequencing of mutations. The article also presents an example of designing a while-loop based function using the new design recipe.

Using Video Game Development to Motivate Program Design and Algebra Among Inner-City High School Students

Introducing inner-city high school students to program design presents unique challenges. The typical assumptions of an introductory programming course, like students understand what variables and functions are, may not be safe. Therefore, asking students to define functions as part of the program design process may be an overwhelming task. Many students do not understand that a function is an abstraction over similar expressions and that parameters represent the differences among these expressions. This articles presents a novel approach to teaching program design to high school students while simultaneously reinforcing high school algebra. The approach is based on a design recipe to help students develop the abstractions that lead to functions. Using a bottom-up approach, students are taught how to abstract over similar expressions. They are then taught how to use high school algebra concepts, like compound functions and function composition, to also design functions. In addition, the article also presents empirical data collected from students to measure their reaction to the course. For the students in the course, the empirical data suggests that high school algebra concepts are successfully reinforced and that students feel they become better problem solvers, find programming intellectually stimulating, and walk away with an interest in programming.

Visual Designing and Debugging of Deterministic Finite-State Machines in FSM

This article presents a visualization tool for designing and debugging deterministic finite-state machines in FSM -- a domain specific language for the automata theory classroom. Like other automata visualization tools, users can edit machines and observe their execution, given some input. Unlike other automata visualization tools, the user is not burdened nor distracted with rendering a machine as a graph. Furthermore, emphasis is placed on the design of machines and this article presents a novel design recipe for deterministic finite-state machines. In support of the design process, the visualization tool allows for each state to be associated with an invariant predicate. During machine execution, the visualization tool indicates if the proposed invariant holds or does not hold after each transition. In this manner, students can validate and debug their machines before attempting to prove partial correctness or submitting for grading. In addition, any machine edited with the visualization tool can be rendered as executable code. The interface of the visualization tool along with extended examples of its use are presented.

Effective medium theory for thermal scattering off rotating structures.

Controlling heat transfer with artificial functional materials has been a promising route towards the efficient and smart utilization of thermal energy in modern society. At the macroscopic scale, thermal metamaterials have demonstrated versatile functionalities in manipulating thermal conduction. One major method is the effective medium theory, which provides a reliable approximation for the material parameters of the composite. Although most of thermal metamaterials use static components, recent devices with integrated moving parts are attracting great interest thanks to their high efficiency and flexibility. However, the effective medium theory for thermal scattering off such devices has not been well established, due to the fundamental difference between thermal convection and conduction. Here, we provide a thorough study on heat transfer through mechanically rotating structures. It is shown that the effective thermal conductivity of a rotating structure can be rigorously described in a complex plane. The analytical expressions of the effective thermal conductivity for structures with rotating multiple layers are formulated, which explicitly capture their influences on the surrounding temperature field. We validate the theory and numerically demonstrate the rotated and unrotated temperature distributions generated around a single structure. Our theory is expected to become a design recipe for novel thermal metamaterials and meta-devices.

On the Safety Hierarchy and Hierarchy of Controls

History reveals an ever-increasing caboodle of protective measures for assuring an acceptable level of safety for both new product designs and for the remediation of man-made and natural hazards. Some seventy years ago, safety professionals began to functionally categorize these safety tools and rank the categories according to their perceived effectiveness. At first, the resulting hierarchies were designated Safety Hierarchies; later updated versions are now referred to as Hierarchies of Controls. To characterize Hierarchies, sixty-six references were surveyed that were published after 1952. Each of these design recipes begin with the admonition “Eliminate the hazards.” All of the hierarchies were created using consensus or speculation, not research. We establish that the Safety Hierarchies and the Hierarchies of Controls are merely rules of thumb, not theorems. Generally, different hierarchies give rise to different designs. The principal strength of both Hierarchies is their replacement of the myth of colloquial safety as “freedom from harm” with a realistic technical definition of safety as an “acceptable level of risk” that is systematically achievable however tortuous.

Message Design Recipes Inducing Sharing-Service Customer’s Intention of Performing a Given Role: Using Fuzzy-Set Qualitative Comparative Analysis

Message Design Recipes Inducing Sharing-Service Customer’s Intention of Performing a Given Role: Using Fuzzy-Set Qualitative Comparative Analysis