Microscale Areas Research Articles

Nondestructive Nano-Imaging and Nano-Spectroscopy of Buried Battery Interfaces: Advancing in Situ and Operando Infrared Characterization Schemes for Basic Energy Storage Science

A critical component to the advancement and realization of beyond Li-ion electrical energy storage technologies is the careful study and characterization of the electrochemically active interfaces that govern the function and performance of such devices. Ideally, characterization of interfaces, and the interphases that grow therein, would be done in an inherently non-destructive way, while within its undisturbed native environment, and with nanoscale resolution over microscale areas (to resolve the kinds, and distribution, of the interphase building blocks). The practical realization of this, though, is extremely challenging because these interfaces and interphases are buried, highly reactive, nano-thin, and structurally and chemically heterogenous.In this talk, we’ll discuss a brief history of an emerging and evolving infrared near-field methodology aimed at overcoming as many of these challenges as possible, to study electrochemical energy storage materials and interfaces in their native environment, non-destructively, and with nanoscale resolution. This is accomplished by employing a combination of precisely engineered and electrochemically controlled graphene/electrolyte interfaces, and diffraction-limit-breaking near-field optical probes capable of chemical imaging and vibrational spectroscopy at the nanoscale. We will present works published on graphene/liquid-electrolyte interfaces,1 and anode-free-based Li/polymer-electrolyte interfaces.2 We will show that in the former case, operando potential step voltammetry + nano-FTIR is capable of sensing concentration changes in the electric double layer.1 Furthermore, in the latter case, where we will spend most our time, in situ multimodal nano-FTIR, ATR-FTIR, infrared nano-imaging, and atomic force microscopy reveal nanoscale structural and chemical heterogeneities intrinsic to the solid polymer electrolyte initiate a cascade of additional interfacial nanoscale heterogeneities during Li plating and stripping, including Li-ion conductivity, electrolyte decomposition, and interphase formation.2 1.) Y.-H. Lu,* J.M. Larson,* A. Baskin, X. Zhao, P. Ashby, D. Prendergast, H. Bechtel, R. Kostecki, and M. Salmeron, Nano Lett 19, 5388-5393 (2019). 2.) X. He*, J. M. Larson*, H. A. Bechtel, and R. Kostecki, Nat Commun, 13, 1398 (2022).(*: Denotes Equal Contribution) Figure 1

Precipitation behavior of Al-Zn-Mg-Cu alloys with the coupled soft/hard micro-scale areas and its effect on properties

A novel thermomechanical processing route was developed to prepare Al-Zn-Mg-Cu alloys containing heterostructures with coupled soft/hard micro-scale areas. The heterostructure gives an effect on the subsequent precipitation behavior of alloys. Importantly, the tensile strengths, elongation and corrosion resistance of grain boundaries of the #3 alloy with an appropriate coupled distribution of soft/hard micro-scale areas are all greatly improved compared with the alloy with the homogeneous structure. Based on the detailed microstructure characterization, the corresponding strengthening and corrosion resistance mechanisms of alloys with heterostructure have been established in this paper.

How to rapidly map outdoor mean radiation temperatures with high-spatial-resolution from UAV-derived multimodal images: A case study in Guangzhou

Mean radiation temperatures (MRTs) have gained widespread attention due to its close relationship with human health. Notwithstanding the availability of existing methods for evaluating MRT (such as ground-based measurements and numerical simulations), it remains a challenge to rapidly and accurately acquire MRTs with a high spatial resolution. This study thus proposed an efficient methodology for evaluating spatial MRTs of urban spaces on the microscale through multimodal images derived from unmanned aerial vehicles (UAVs). Based on UAVs and near-ground measurements, point-cloud data characterizing long- and short-wave irradiance from three-dimensional (3D) surfaces were obtained via photogrammetry and retrieval models. Spatial MRTs were then sampled based on a mapped 3D radiation field and ray-tracing. Comparison of the sampled MRTs with measured MRTs (near the ground) through globe temperatures exhibited a high consistency (R2: 0.980, RMSE: 3.080 °C) and a small difference (almost less than 2.5 °C), demonstrating the applicability and accuracy of our proposed method. In conjunction with near-ground meteorological variables, outdoor thermal comfort (OTC) indicators with a high spatial resolution were derived; further comparisons suggested the SET* and UTCI as ideal indicators to evaluate microscale OTC of hot and humid areas through our method. From the perspective of application, this method can further refine the assessment of the urban thermal environment as well as the human thermal comfort of micro-scale spaces based on simulations or remote sensing observations with lower spatial resolution, which will provide specific suggestions for redesign or redevelopment of the micro-scale areas. Additionally, the thermal mapping with high spatial resolution obtained by this method can also be used as a reference to evaluate the accuracy of related numerical models.

Improving the urban wind flow prediction efficiency of target area by considering its surrounding buildings impact

Rapid urbanization has caused various urban environmental challenges, including the emergence of urban heat island and air pollution. Urban wind flow is a crucial factor shaping the urban environment, which needs effective prediction and design. Computational fluid dynamics is commonly used for prediction and design of urban wind environment. However, high-accuracy simulation of wind flow, especially considering the layouts of full-scale and complex buildings, requires intensive computational resources. Typically, simulations simplify the surrounding building layouts (e.g., building layers) of target areas, potentially impacting simulation accuracy. It is imperative to determine appropriate building layers around different-scale target areas for effective wind flow simulation. This work explored the simulated wind flow characteristics of multi-scale (local, micro, and building-scale) target areas with different building layers defined as H, L, H/L, and L/H (H and L representing the vertical and horizontal maximum sizes of target area). The recommended building layers for local-scale, micro-scale, and building-scale target areas were at least 3L, 4H, and 5H, respectively, ensuing the relative errors between simulated and measured wind velocities remained below 20 %. This method largely reduced the calculation time by 73 % compared with full-scale simulation. This work can provide guidelines for fast prediction and design of urban wind environment, further promoting the sustainable development of urban cities.

Local Manipulation of Skyrmion Nucleation in Microscale Areas of a Thin Film with Nitrogen-Ion Implantation.

Precise manipulation of skyrmion nucleation in microscale or nanoscale areas of thin films is a critical issue in developing high-efficient skyrmionic memories and logic devices. Presently, the mainstream controlling strategies focus on the application of external stimuli to tailor the intrinsic attributes of charge, spin, and lattice. This work reports effective skyrmion manipulation by controllably modifying the lattice defect through ion implantation, which is potentially compatible with large-scale integrated circuit technology. By implanting an appropriate dose of nitrogen ions into a Pt/Co/Ta multilayer film, the defect density was effectively enhanced to induce an apparent modulation of magnetic anisotropy, consequently boosting the skyrmion nucleation. Furthermore, the local control of skyrmions in microscale areas of the macroscopic film was realized by combining the ion implantation with micromachining technology, demonstrating a potential application in both binary storage and multistate storage. These findings provide a new approach to advancing the functionalization and application of skyrmionic devices.

Characterisation of gamma-irradiated MCz-silicon detectors with a high-K negative oxide as field insulator

Abstract The high-luminosity operation of the Tracker in the Compact Muon Solenid (CMS) detector at the Large Hadron Collider (LHC) experiment calls for the development of silicon-based sensors. This involves implementation of AC-coupling to micro-scale pixel sensor areas to provide enhanced isolation of radiation-induced leakage currents. The motivation of this study is the development of AC-pixel sensors with negative oxides (such as aluminium oxide — Al2O3 and hafnium oxide — HfO2) as field insulators that possess good dielectric strength and provide radiation hardness. Thin films of Al2O3 and HfO2 grown by atomic layer deposition (ALD) method were used as dielectrics for capacitive coupling. A comparison study based on dielectric material used in MOS capacitors indicate HfO2 as a better candidate since it provides higher sensitivity (where, the term sensitivity is defined as the ratio of the change in flat-band voltage to dose) to negative charge accumulation with gamma irradiation. Further, space charge sign inversion was observed for sensors processed on high resistivity p-type Magnetic Czochralski silicon (MCz-Si) substrates that were irradiated with gamma rays up to a dose of 1 MGy. The inter-pixel resistance values of heavily gamma irradiated AC-coupled pixel sensors suggest that high-K negative oxides as field insulators provide a good electrical isolation between the pixels.

Legitimacy and limitations of valuing the oxygen production of ecosystems

Oxygen production is an ecosystem service essential to life on Earth. However how it should be valued is controversial and depends on several factors. Here, we commented on how valuation might be applicable to the stock or flow of oxygen, whether additional oxygen produced at the micro or macro scale provides additional human wellbeing, and whether double counting may occur if oxygen production and carbon sequestration are both valued independently and added. We concluded that the flow of oxygen produced by ecosystems should be valued when: (1) high levels of atmospheric oxygen at specific micro-scale areas (e.g., a park) provides additional benefits to local human health and additional attraction to tourists; (2) micro-scale aquatic oxygen production (e.g., in a pond or aquafarm) avoids potential loss of aquatic products; and (3) macro-scale aquatic oxygen production (e.g., in global oceans) maintains marine contributions to humans (e.g., fishery resources). However, whether macro-scale atmospheric oxygen production should be valued is uncertian, because the effects of declining global atmospheric oxygen, especially in the short term, remain unclear. This needs further research. We also concluded that the values of oxygen production and carbon sequestration can be aggregated without double counting, given that the values are not duplicated in multiple ecosystem service categories. For example, oxygen production is best considered as contributing to gas regulation while carbon sequestration contributes to climate regulation. But one should not count and add both carbon sequestration and oxygen production as contributing to both gas and climate regulation. Techniques for valuing oxygen production may include the willingness to pay for additional health benefits of breathing extra high levels of atmospheric oxygen, the market price of industrial oxygen, the travel cost to natural ‘oxygen bars’, the avoided cost of losing aquatic resources, and the replacement cost of using artificial techniques to produce oxygen.

Simultaneous Micro- and Nanoscale Silicon Fabrication by Metal-Assisted Chemical Etch

Abstract Simultaneous micro- and nanoscale etching of silicon on a wafer-scale is nowadays performed using plasma etching techniques. These plasma techniques, however, suffer from low throughput due to aspect-ratio dependent etch (ARDE) rate, etch lag from changes in feature size, loading effects from increased etch area, and undesirable surface characteristics such as sidewall taper and scalloping, which are particularly problematic at the nanoscale and can affect the etch uniformity. Additionally, the hardware required for plasma etching can be very expensive. A potential alternative, which addresses the above issues with plasma etching is metal assisted chemical etch (MacEtch). To date, however, an integrated micro- and nanoscale MacEtch process, which has uniform and clean (i.e., without nanowire-like defects in microscale areas) etch front has not been presented in the literature. In this work, we present for the first time a feasible process flow for simultaneous micro-and nanoscale silicon etching without nanowire-like defects, which we call integrated micro- and nanoscale MacEtch (IMN-MacEtch). Successful etching of silicon features ranging from 100 nm to 100 μm was achieved with etch rates of about 1.8 μm/min in a single step to achieve features with an aspect ratio (AR) ∼18:1. We thus conclude that the process represents a feasible alternative to current dry etch methods for patterning feature sizes spanning three orders of magnitude.

A Micro-Scale Study of Flood Risk Assessment in Urban Fluvial Areas Using the Flood Potential Index

Worldwide, increasing various methods are being offered to solve the issue of flood disasters in urban fluvial areas, yet there is a relative lack of micro-scale studies concerning the flood potential index (FPI) to forecast future flood events in DKI Jakarta. With recent advances, the information of flood risk assessment can be monitored and communicated by using FPI embedded with a geographical information system (GIS)-based model. Therefore, the main purpose and concerned issue in this paper is how to relate the micro-scale study of flood risk assessment in the urban fluvial area in DKI Jakarta as the study case using FPI. Specific parameters were selected to develop and analyze FPI, involving three considerations: meteorological, physical-environment, and socio-economic aspects. The classification has also been developed by the analysis of data from rainfall, normalized difference vegetation index (NDVI) obtained from Landsat eight interpretation, and population density to produce a flood potential hazard map for each sub-district in DKI Jakarta during 2021–2024. The results of the completed analysis of classification for each sub-district in DKI Jakarta showed 10 sub-districts with high potential, 219 sub-districts with medium potential, and 32 sub-districts with low potential in 2024. Our findings also confirmed that using a GIS approach in identifying and measuring the FPI in DKI Jakarta for micro-scale areas is very helpful in order to develop better adaptive local flood management practices. For future works, the assessment not only produces a visualization of the flood potential index but also estimates possible damage due to the flood hazard itself.

Characterization of Heavily Irradiated Dielectrics for Pixel Sensors Coupling Insulator Applications

An increase in the radiation levels during the high-luminosity operation of the Large Hadron Collider calls for the development of silicon-based pixel detectors that are used for particle tracking and vertex reconstruction. Unlike the conventionally used conductively coupled (DC-coupled) detectors that are prone to an increment in leakage currents due to radiation, capacitively coupled (AC-coupled) detectors are anticipated to be in operation in future collider experiments suitable for tracking purposes. The implementation of AC-coupling to micro-scale pixel sensor areas enables one to provide an enhanced isolation of radiation-induced leakage currents. The motivation of this study is the development of new generation capacitively coupled (AC-coupled) pixel sensors with coupling insulators having good dielectric strength and radiation hardness simultaneously. The AC-coupling insulator thin films were aluminum oxide (Al2O3) and hafnium oxide (HfO2) grown by the atomic layer deposition (ALD) method. A comparison study was performed based on the dielectric material used in MOS, MOSFET, and AC-coupled pixel prototypes processed on high resistivity p-type Magnetic Czochralski silicon (MCz-Si) substrates. Post-irradiation studies with 10 MeV protons up to a fluence of 1015 protons/cm2 suggest HfO2 to be a better candidate as it provides higher sensitivity with negative charge accumulation on irradiation. Furthermore, even though the nature of the dielectric does not affect the electric field within the AC-coupled pixel sensor, samples with HfO2 are comparatively less susceptible to undergo an early breakdown due to irradiation. Edge-transient current technique (e-TCT) measurements show a prominent double-junction effect as expected in heavily irradiated p-type detectors, in accordance with the simulation studies.

Avian pallial circuits and cognition: A comparison to mammals.

Cognitive functions are similar in birds and mammals. So, are therefore pallial cellular circuits and neuronal computations also alike? In search of answers, we move in from bird's pallial connectomes, to cortex-like sensory canonical circuits and connections, to forebrain micro-circuitries and finally to the avian "prefrontal" area. This voyage from macro- to micro-scale networks and areas reveals that both birds and mammals evolved similar neural and computational properties in either convergent or parallel manner, based upon circuitries inherited from common ancestry. Thus, these two vertebrate classes evolved separately within 315 million years with highly similar pallial architectures that produce comparable cognitive functions.

Mineral Heterogeneity Characterization of the Lacustrine Yanchang Shales, Ordos Basin Using Micro-Fourier Transform Infrared Spectroscopy (Micro-FTIR) Technique

Shale is a typical fine-grained sedimentary rock with small grain sizes of matrix components, significant lithofacies variation of rock texture and structure, and strong heterogeneity of organic matter and mineral compositions. Characterization of mineral compositions and their heterogeneity in micro- to nanoscale are the key parameters to gas shale pore structure and rock physical properties. In order to study the microscale mineralogy heterogeneity of the lacustrine shales in the Triassic Yanchang Formation in the Ordos Basin, the micro-Fourier transform infrared spectroscopy (micro-FTIR) technique was conducted. Based on the specific micro-FTIR spectra peaks, the abundance of mineral compositions can be quantitatively determined in the selected microscale areas. The results show that within the range of 80 μm micro-FTIR test interval, both massive argillaceous shale and silty interlayered shale show obvious heterogeneity; in particular, the relatively homogeneous shale observed by the naked eyes also has strong mineral heterogeneity. The results of micro-FTIR spectra are basically consistent with the bulk X-ray diffraction (XRD) data. The advantage of this micro-FTIR technique includes higher resolution (less than 100 μm) and in situ mineral characterization of shale samples at micro- and nanoscale.

Spontaneous Formation of Ordered Magnetic Domains by Patterning Stress.

The formation of ordered magnetic domains in thin films is important for the magnetic microdevices in spin-electronics, magneto-optics, and magnetic microelectromechanical systems. Although inducing anisotropic stress in magnetostrictive materials can achieve the domain assembly, controlling magnetic anisotropy over microscale areas is challenging. In this work, we realized the microscopic patterning of magnetic domains by engineering stress distribution. Deposition of ferromagnetic thin films on nanotrenched polymeric layers induced tensile stress at the interfaces, giving rise to the directional magnetoelastic coupling to form ordered domains spontaneously. By changing the periodicity and shape of nanotrenches, we spatially tuned the geometric configuration of domains by design. Theoretical analysis and micromagnetic characterization confirmed that the local stress distribution by the topographic confinement dominates the forming mechanism of the directed magnetization.

Forecasting Charging Demand of Electric Vehicles Using Time-Series Models

This study compared the methods used to forecast increases in power consumption caused by the rising popularity of electric vehicles (EVs). An excellent model for each region was proposed using multiple scaled geographical datasets over two years. EV charging volumes are influenced by various factors, including the condition of a vehicle, the battery’s state-of-charge (SOC), and the distance to the destination. However, power suppliers cannot easily access this information due to privacy issues. Despite a lack of individual information, this study compared various modeling techniques, including trigonometric exponential smoothing state space (i.e., Trigonometric, Box–Cox, Auto-Regressive-Moving-Average (ARMA), Trend, and Seasonality (TBATS)), autoregressive integrated moving average (ARIMA), artificial neural networks (ANN), and long short-term memory (LSTM) modeling, based on past values and exogenous variables. The effect of exogenous variables was evaluated in macro- and micro-scale geographical areas, and the importance of historic data was verified. The basic statistics regarding the number of charging stations and the volume of charging in each region are expected to aid the formulation of a method that can be used by power suppliers.

Risk analysis of a cross-regional toxic chemical disaster by using the integrated mesoscale and microscale consequence analysis model

The rapidly growing capacity and scale of the world's petrochemical industries have forced many plants to have an even larger amount of hazardous substances. Once a serious leak occurs, the outcome of the effect zone could be very large or even uncontrollable just like the Bhopal disaster. In order to assess the risk of a cross-regional damage, this study aims to develop a model that can combine the benefits of both CFD model of the microscale simulation and the Gaussian dispersion model of the mesoscale simulation.The developed integrated model is employed on a toxic chemical tank leak accident of a process plant within an industrial park in order to explore the consequences and the risk of the toxic gas dispersion on three different scopes; one is the accident site, the second is the long-distance transmission route of the mesoscale area and the third is a target city. According to the simulation's results, it is obvious that the complexity of the structure surrounding the leaking tank will eventually affect the maximum ground concentration, the cloud shapes and cloud dilution rate, while the released gas is under dispersion. On the other hand, since the simple Gaussian dispersion model doesn't consider the above impacts, its calculation results will have many differences as compared to the realistic situation. This integrated model can be used as a tool for estimating the risk on a microscale or mesoscale areas and it can produce better results when an environmental impact analysis is required for a larger hazardous chemical process.

Evaluation and mapping of building overheating risk and air conditioning use due to the urban heat island effect

Differences in urban context can lead to distinct local microclimates. The data provided by a single weather station are insufficient for evaluating residential thermal conditions and the air conditioning energy consumption of microscale areas throughout cities. The purpose of this study was to quantify the urban heat island (UHI) effect on air conditioning energy consumption and overheating risk in buildings. This study generated localized microclimate files of microscale areas from their urban contexts. A common three-story townhouse in Tainan City, Taiwan, was used as an example. EnergyPlus was used to simulate and analyze the effect of microclimate on residential overheating risk and air conditioning energy consumption citywide. Tainan was divided into 1496 microscale areas, and the analysis results indicated that dwellings in downtown and suburban areas faced an overheating risk for 3–5 months and exhibited a natural ventilation potential of 43%–47% from May to October. Furthermore, the air conditioning energy consumption of 60% of these microscale areas was 14.5–21.5 kWh/m2, with 8% exceeding 21.5 kWh/m2. By contrast, the natural ventilation potential of dwellings in the countryside and peripheral areas was 63%–72%, and air conditioning energy consumption was ≤11.0 kWh/m2. These results highlight the importance of using localized microclimate files for evaluating building energy performance in urban areas.

Dual‐Region Resonant Meander Metamaterial

AbstractMetamaterials are engineered structures designed to interact with electromagnetic radiation, whereby the frequency range in which metamaterials respond depends on their dimensions. In this paper, it is demonstrated that a metamaterial can be functional in more than one frequency region. An advanced metamaterial is demonstrated that can interact with both terahertz (THz) and near‐infrared (NIR) frequencies, concurrently. This work exploits meander line resonators with nanoscale linewidth distributed over microscale areas, and experimentally demonstrates that such a metamaterial can simultaneously interact with NIR and THz waves. The engineered metamaterial acts as a plasmonic grating in the NIR range and simultaneously acts as an array of electric resonators in the THz range. Moreover, the performance of the engineered metamaterial is polarization‐independent in both wavelength regions. Finally, a unique feature of the proposed metamaterial is that it enables resonant frequency tuning in the THz region without affecting the NIR response. All these novel advantages of dual‐band meander metamaterial make it an ideal alternative for cutting‐edge applications such as bi‐functional sensing, imaging, filtering, modulation, and absorption.

1-nm-Wide Hydrated Dipole Arrays Regulate AuNW Assembly on Striped Monolayers in Nonpolar Solvent

Summary We show that striped phases of horizontally oriented phospholipids presenting 1-nm-wide orientable dipole arrays can order and straighten flexible 2-nm-diameter gold nanowires (AuNWs) with lengths (up to 1 μm) that greatly exceed the template pitch (∼7.5 nm). AuNW ordering can extend over areas > 100 μm2. Whereas wires bundle in solution, with contact between ligand shells, wires adsorbing to the template separate to much larger center-to-center distances (e.g., 12–30 nm) near multiples of the template pitch, consistent with repulsive interactions between wires emerging during interactions with dipole arrays in the template. AuNW assembly was carried out in cyclohexane, a nonpolar solvent. Interestingly, we found that wire ordering was contingent on the extent of phospholipid headgroup hydration and the presence of excess oleylamine, which assembled into hemicylindrical micelles around the hydrated headgroups. Together, these components generated a protected polar environment that enabled the phospholipid headgroups to function collectively to regulate AuNW assembly.

Magnetostructural phase transitions and magnetocaloric effect in Mn(As,P) compounds and their composites

The magnetostructural phase transition in Mn(As,P) compounds was studied by a combination of X-ray diffraction on single crystals and by the magnetisation measurements. The mentioned transition is accompanied by anisotropic deformation of the crystal lattice, magnetisation hopping and heat evolving due to a large magnetocaloric effect (MCE). It is shown that this transition is a transformation from the hexagonal ferromagnetic to the orthorhombic paramagnetic phase at heating above the Curie temperature (TC). The values of the magnetic and lattice entropy changes at phase transition are obtained and the adiabatic temperature change is estimated in the frame of Clapeyron-Clausius relations. It is found that the MCE in the magnetic field 140 kOe reaches the value of 13.5 K. It is shown that a superparamagnetic structure (as a conglomerate of microscale areas) is formed above Curie temperature in zero magnetic field. On the other hand at the temperatures above the TC the ferromagnetic state is induced by magnetic fields exceeding the certain critical value Hcr while the above-mentioned superparamagnetic state is destroyed by the same magnetic fields. The magnetic properties of the bulk Mn(As,P) and the polymeric composite based on Mn(As,P) compound are compared.

The influence of low impact development-best management practices implementation on surface runoff reduction: A case study in Universitas Indonesia catchment area

High population growth rate will increase the infrastructure development, so the impervious land cover in a certain area will be greater. In 2016, the percentage of impervious area in UI Depok catchment area has reached 57%. This condition causes the surface runoff volume and probability of flood will increase. LID is a new paradigm for stormwater management in micro-scale areas. LID infrastructure is designed to manage stormwater for light to moderate rainfall spectrum. Previous research has produced an applied proposal of various LID-BMP infrastructure in UI catchment area, Depok, by using BMP Siting Tools. This study aims to compare the volume of surface runoff without and with the LID infrastructures on UI catchment area, Depok, and to calculate the effectiveness of LID infrastructure for various spectrum of rainfall. The LID infrastructures used are bioretention, porous pavement, infiltration trench, infiltration basin, vegetated filter strip, sand filter non-surface, sand filter surface, rain barrel and grassed swales. By applying said infrastructures, the reduction of peak flow on various rain spectrums vary from 3-30%.