Advanced Materials Corporation (United States)

Alternating current poling (ACP) has been investigated showing dramatic enhancement of the piezoelectric and dielectric properties of PMN-PT and PIN-PMN-PT single crystals. However, reported studies have been mainly focused on material or simulation study. In this work, we investigated ultrasound transducers with alternating current poling (ACP) Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT) single crystals and compared the key specifications of ACP single crystal transducers with those of conventional direct current poling (DCP) single crystal prototypes. Based on the measured material properties, single layer ultrasound transducers were first designed with a center frequency of 10 MHz with the KLM (Krimholtz, Leedom and Matthae) model. Then, the prototypes were fabricated using ACP and DCP single crystals. After that, the performances of two different kinds of transducers were characterized by comparison of sensitivity, pressure output, bandwidth and imaging quality. At last, the ACP transducer durability was tested with long working hours, which showed a low and recoverable decrease with the transducer’s performance. With an aperture size of 2×2 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>, ACP transducers showed a better electrical impedance, 14% improvement in loop sensitivity and 66% improvement in pressure output compared with DCP transducers . For the imaging test, although the ACP transducers showed comparable resolution with the DCP transducers for the in-vitro wire phantom imaging, the ACP transducers showed 3 dB signal to noise ratio improvement under the same input. These findings suggest that ACP single crystal transducers are promising for diagnostic and therapeutic applications.

Forest ecosystems play a critical role in maintaining key ecosystem services and functions. However, the impacts of climate change have become apparent in recent years. Long-term forest observation data suggest that deciduous forests are being replaced by evergreen tree species, potentially as a result of climate change. Detecting such ecosystem changes at an early stage is crucial for assessing the impacts of climate change and implementing effective management. In this study, we aim to develop a method for identifying evergreen trees in deciduous broadleaf forests where the effects of climate change are becoming apparent. Specifically, we employed cost-effective and efficient UAV-LiDAR technology. By focusing on the deciduous season, we effectively enhanced the detection of evergreen trees, as their presence becomes more distinguishable during this period.The study was conducted in a 6-hectare plot within the deciduous broadleaf forests of the Ogawa Forest Reserve in Japan, a site where long-term forest monitoring has been conducted. This site harbors Pieris japonica subsp. japonica (hereafter, PJ), an evergreen shrub that has shown an increase in recent years. Other species that retain green leaves during the deciduous season, such as dwarf bamboo (Sasa) and epiphytic plants, are also present. To ensure effective detection of PJ, we first stratified the acquired LiDAR data into different canopy layers (upper canopy trees and multiple understory layers). We then determined the required point density for rational segmentation of PJ. Using RGB data, we extracted "green" points for each canopy layer. This method effectively excluded dwarf bamboo and epiphytic plants, enabling the accurate extraction of PJ. The study demonstrated that combining UAV-LiDAR with RGB data is highly effective for identifying understory evergreen trees. This approach facilitates the extraction of "green" objects by canopy layer in deciduous forests during the deciduous season. This method would be not only efficient for detecting forest changes but also applicable to identifying invasive species and enhancing forest management practices.

ISO Standard 23519:2010 defines the surface roughness of sintered metal parts: Rk and Rpk, and it intends to provide relevant surface roughness data regardless of porosity,- however the data reliability tends to be insufficient in practice. The following parameters might influence the surface roughness data in accordance with the standard such as; measuring probe, instruments, filters, and others. The effect of such parameters was investigated and compared with an optical method using white light interferometry. 3 different measuring instruments were used. The measured surfaces of specimens having density of 6.4, 6.8 and 7.2 are punch facing side. In this study, details of the results are presented.

High strength low alloy (HSLA) steels are known for their superior mechanical properties, which are achieved through alloying elements and controlled hot rolling. In this work, the effect of cooling rate and alloying elements on the final microstructure and mechanical properties of Ti-V HSLA microalloyed steels were investigated. The Gleeble 1500TM TM was used to simulate the plate rolling process. The samples were cooled to room temperature using two different cooling rates to simulate the 16 and 30mm thick plate cooling patterns in the alloy. Increasing the cooling rate and amount of carbon equivalent promoted acicular ferrite and bainite transformation, and also led to the decrease in grain size. Consequently, both the yield strength and UTS increased with increasing cooling rate with a slight drop in uniform elongations.

Inorganic 2D materials offer a new approach to controlling mass diffusion at the nanoscale. Controlling ion transport in nanofluidics is key to energy conversion, energy storage, water purification, and numerous other applications wherein persistent challenges for efficient separation must be addressed. The recent development of 2D membranes in the emerging field of energy harvesting, water desalination, and proton/Li-ion production in the context of green energy and environmental technology is herein discussed. The fundamental mechanisms, 2D membrane fabrication, and challenges toward practical applications are highlighted. Finally, the fundamental issues of thermodynamics and kinetics are outlined along with potential membrane designs that must be resolved to bridge the gap between lab-scale experiments and production levels.

Novel temporary bonding/debonding system including high heat resistant temporary bonding adhesive and debonding methods with newly developed photonic release by Xe flash light irradiation will be introduced. New temporary bonding adhesive is endurable up to 300 °C and can be easily removed by peeling off after debonding from the support carrier. By adopting the dual layer structure with adhesive layer and metal layer on glass carrier, one-shot Xe flash light irradiation within 5 ms enables debonding cleanly, indicating the increased throughput at debonding step. Process demonstration results of wafer thinning down to 50 μm, fan-out wafer level packaging (FOWLP) will also be shown.

Abstract BackgroundChi and colleagues have argued that some of the most challenging engineering concepts exhibit properties of emergent systems. However, students often lack a mental framework, or schema, for understanding emergence. Slotta and Chi posited that helping students develop a schema for emergent systems, referred to as schema training, would increase the understanding of challenging concepts exhibiting emergent properties.PurposeWe tested the effectiveness of schema training and explored the nature of challenging concepts from thermodynamics and heat transfer. We investigated if schema training could (a) repair misconceptions in advanced engineering students and (b) prevent them in beginning engineering students.MethodWe adapted Slotta and Chi's schema training modules and tested their impact in two studies that employed an experimental design. Items from the Thermal and Transport Concept Inventory and expert‐developed multiple‐choice questions were used to evaluate conceptual understanding of the participants. The language used by students in their open‐ended explanations of multiple‐choice questions was also coded.ResultsIn both studies, students in the experimental groups showed larger gains in their understanding of some concepts—specifically in dye diffusion and microfluidics in Study One, and in the final test for thermodynamics in Study Two. But in neither study did students exhibit any gain in conceptual questions about heat transfer.ConclusionOur studies suggest the importance of examining the nature of the phenomena underlying the concepts being taught because the language used in instruction has implications for how students understand them. Therefore, we suggest that instructors reflect on their own understanding of the concepts.

High fatigue strength is one of the major requirements for dental implant materials. It was previously shown that the fatigue strength under conventional stress‐control tension–compression testing can be doubled for commercially pure (CP) titanium processed by equal channel angular pressing. However, the fatigue endurance of an implant exposed to cyclic loading in corrosive media (bodily fluids) may potentially be compromised. In this work, non‐conventional bending fatigue testing in air and in simulated body fluid (SBF) has been carried out for coarse‐grained and ultrafine‐grained CP titanium.

We develop a loosely coupled fluid‐structure interaction finite element solver based on the Lie operator splitting scheme. The scheme is applied to the interaction between an incompressible, viscous, Newtonian fluid, and a multilayered structure, which consists of a thin elastic layer and a thick poroelastic material. The thin layer is modeled using the linearly elastic Koiter membrane model, while the thick poroelastic layer is modeled as a Biot system. We prove a conditional stability of the scheme and derive error estimates. Theoretical results are supported with numerical examples. © 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 31: 1054–1100, 2015