Indentation and reciprocating wear tests are carried out to study dent and wear resistance of superelastic Ti-Ni alloys. The effect of loading rate on the superelastic behavior of TiNi under indentation loading is inv...Indentation and reciprocating wear tests are carried out to study dent and wear resistance of superelastic Ti-Ni alloys. The effect of loading rate on the superelastic behavior of TiNi under indentation loading is investigated and compared to a new generation of shape memory alloys, i.e., 60NiTi. Only limited amount of work has been done to investigate the dependency of superelasticity on loading rate of TiNi under localized compressive loads, but much work is directed towards understanding the effect of strain rate on tensile properties. Understanding the superelastic behavior helps to employ superelastic alloys in applications where high impact loading is expected as in bearings and gears. In the present study, it is found that dent resistance of Ti-Ni alloy is not significantly affected by loading rate (within the employed loading conditions). It has also been found that new-generation 60NiTi alloy exhibits superior wear and dent resistance, as well as higher hardness compared to equiatomic TiNi.展开更多
Due to their light weight, high corrosion resistance and good heat conductivity, aluminium alloys are used in many industries today. They are suitable for manufacturing many automotive components such as clutch housin...Due to their light weight, high corrosion resistance and good heat conductivity, aluminium alloys are used in many industries today. They are suitable for manufacturing many automotive components such as clutch housings. These alloys can be fabricated by powder metallurgy and casting methods, in which porosity is a common feature. The presence of pores is responsible for reducing their strength, ductility and wear resistance. The present study aims to establish an understanding of the tribological behavior of high pressure die cast Al A380M and powder metallurgy synthesized Al 6061. In this study, dry sliding wear behavior of Al A380M and Al 6061 alloys was investigated under low loads (1.5 N – 5 N) against AISI 52100 bearing steel ball using a reciprocating ball-on-flat configuration and frequency of 10 Hz. Wear mechanisms were studied through microscopic examination of the wear tracks. This study revealed that due to combined effect of real area of contact and subsurface cracking, wear rate increased with increasing porosity content. The difference in friction and wear behavior between received Al A380M and Al 6061 is attributed to their hardness differences.展开更多
Phage Display technology provides a mechanism for us to make bio-recognition elements on biosensors for detection of Salmonella enterica serovars. In the procedure, the filamentous M13 bacteriophage is used for acquir...Phage Display technology provides a mechanism for us to make bio-recognition elements on biosensors for detection of Salmonella enterica serovars. In the procedure, the filamentous M13 bacteriophage is used for acquiring peptides that have a high affinity for the target recognition. Our approach in this study was to develop peptide structures in the pIII region of this thread-shaped virus. A phage pIII library was used to perform biopanning for the phage clones to bind the target Salmonella serovars. The clones were bound, washed, eluted and amplified four times. Then, the phage peptides were sequenced tested for specificity using ELISA procedures. In this project to make a biosensor for all relevant Salmonella enterica serovars, we used common LPS salmonellae antigens as targets in the biopanning procedure. This enabled us to have a phage probe specific for all serovars of Salmonella enterica excluding the typhoid organisms. The final phage was then immobilized onto an electromagnetic platform to complete the biosensor, which gives us the real-time ability to measure resonance changes that indicate mass loading. The mass loading is an indication of binding to the target cells. Our current data with an ELISA procedure show the phage probe’s high affinity for salmonellae, very low cross-reactivity with Escherichia coli, Shigella, and no cross-reactivity to Staphylococcus aureus and Listeria monocytogenes. The biosensor with the phage showed that the capture ability for Salmonella serovars is thirty times higher than the control sensor. This biosensor is a candidate for detection of Salmonella in food and other settings.展开更多
Due to light weight, high specific strength, high corrosion resistance and good heat transfer ability, aluminium alloys are becoming attractive for critical structural applications. These alloys can be manufactured us...Due to light weight, high specific strength, high corrosion resistance and good heat transfer ability, aluminium alloys are becoming attractive for critical structural applications. These alloys can be manufactured using powder metallurgy techniques in which porosity is a common characteristic. The presence of pores is responsible for decreasing effective load bearing cross sectional area and inducing stress concentration sites for strain localization and damage, decreasing both strength and ductility. The present study aims to establish a better understanding of the relationship between surface porosity and corresponding wear behavior. In this study, porous specimens were produced using powder metallurgy technique and the extent of wear damage and the type of wear was investigated under low load range of 1.5 - 5 N against AISI 52100 bearing steel ball using a reciprocating ball-on-flat configuration and frequency of 10 Hz. Scanning electron microscopy of the wear tracks and wear debris was carried out to understand wear mechanisms. This study revealed that due to combined effect of high stress intensity and subsurface cracking, wear rate increases with increasing porosity content. The friction and wear behavior of pure Al and Al 6061 as a function of porosity content can be attributed to their hardness and corresponding wear mechanism.展开更多
Subwavelength manipulation of light waves with high precision can enable new and exciting applications in spectroscopy,sensing,and medical imaging.For these applications,miniaturized spectrometers are desirable to ena...Subwavelength manipulation of light waves with high precision can enable new and exciting applications in spectroscopy,sensing,and medical imaging.For these applications,miniaturized spectrometers are desirable to enable the on-chip analysis of spectral information.In particular,for imaging-based spectroscopic sensing mechanisms,the key challenge is to determine the spatial-shift information accurately(i.e.,the spatial displacement introduced by wavelength shift or biological or chemical surface binding),which is similar to the challenge presented by super-resolution imaging.Here,we report a unique"rainbow"trapping metasurface for on-chip spectrometers and sensors.Combined with super-resolution image processing,the low-setting 4×optical microscope system resolves a displacement of the resonant position within 35 nm on the plasmonic rainbow trapping metasurface with a tiny area as small as0.002 mm2.This unique feature of the spatial manipulation of efficiently coupled rainbow plasmonic resonances reveals a new platform for miniaturized on-chip spectroscopic analysis with a spectral resolution of 0.032 nm in wavelength shift.Using this low-setting 4×microscope imaging system,we demonstrate a biosensing resolution of 1.92×109exosomes per milliliter for A549-derived exosomes and distinguish between patient samples and healthy controls using exosomal epidermal growth factor receptor(EGFR)expression values,thereby demonstrating a new on-chip sensing system for personalized accurate bio/chemical sensing applications.展开更多
This work explores the methodology for micron-scale water droplet contact angle derivation for the warty surface of octocoral sclerites. The calcite-made sclerites of the Red Sea octocoral Dendronephthya hemprichi hav...This work explores the methodology for micron-scale water droplet contact angle derivation for the warty surface of octocoral sclerites. The calcite-made sclerites of the Red Sea octocoral Dendronephthya hemprichi have been chosen as a model for this study. Water droplet condensation on the sclerites has been in-situ investigated using Quanta 200 FEG （field emission gun） ESEM （environmental scanning electron microscope） under wet environmental conditions. Two different analysis methods of droplet top and side views have been applied to determine the contact angle based on the secondary electron images. The ESEM image analysis for the sclerites indicates that their surface is hydrophilic. The microscopic contact angle is measured to be 45.3°±6.3°. The macroscopic contact angle has been calculated by using the Wenzel model for the surface texturing of the sclerites.展开更多
Imaging through scattering medium is challenging but important for different applications.Most advances rely on computational image reconstruction from scattering signals.In these conventional investigations,speckles ...Imaging through scattering medium is challenging but important for different applications.Most advances rely on computational image reconstruction from scattering signals.In these conventional investigations,speckles were always treated as scrambled grainy patterns.Directly seeing through scattering diffusers has never been realized.Here,we report a new strategy to see through random diffusers directly using self-imaging of speckles.By analyzing the physics,a direct observation strategy through scattering media is reported with improved image quality.Using this method,we experimentally demonstrated reconstruction-free real-time imaging of static and moving objects with their actual orientation information under single-wavelength and white light illumination.We also proposed a modified speckle autocorrelation imaging(SAI)method inspired by the self-imaging results.Importantly,our strategy requires no pre-calibration or acquisition of point-spread-function,no active control of wavefronts or complicated equipment,nor iterations or carefully adjusted parameters,paving the way towards rapid and high-quality imaging through scattering diffusers.展开更多
This paper explores the evolution of geoscientific inquiry,tracing the progression from traditional physics-based models to modern data-driven approaches facilitated by significant advancements in artificial intellige...This paper explores the evolution of geoscientific inquiry,tracing the progression from traditional physics-based models to modern data-driven approaches facilitated by significant advancements in artificial intelligence(AI)and data collection techniques.Traditional models,which are grounded in physical and numerical frameworks,provide robust explanations by explicitly reconstructing underlying physical processes.However,their limitations in comprehensively capturing Earth’s complexities and uncertainties pose challenges in optimization and real-world applicability.In contrast,contemporary data-driven models,particularly those utilizing machine learning(ML)and deep learning(DL),leverage extensive geoscience data to glean insights without requiring exhaustive theoretical knowledge.ML techniques have shown promise in addressing Earth science-related questions.Nevertheless,challenges such as data scarcity,computational demands,data privacy concerns,and the“black-box”nature of AI models hinder their seamless integration into geoscience.The integration of physics-based and data-driven methodologies into hybrid models presents an alternative paradigm.These models,which incorporate domain knowledge to guide AI methodologies,demonstrate enhanced efficiency and performance with reduced training data requirements.This review provides a comprehensive overview of geoscientific research paradigms,emphasizing untapped opportunities at the intersection of advanced AI techniques and geoscience.It examines major methodologies,showcases advances in large-scale models,and discusses the challenges and prospects that will shape the future landscape of AI in geoscience.The paper outlines a dynamic field ripe with possibilities,poised to unlock new understandings of Earth’s complexities and further advance geoscience exploration.展开更多
文摘Indentation and reciprocating wear tests are carried out to study dent and wear resistance of superelastic Ti-Ni alloys. The effect of loading rate on the superelastic behavior of TiNi under indentation loading is investigated and compared to a new generation of shape memory alloys, i.e., 60NiTi. Only limited amount of work has been done to investigate the dependency of superelasticity on loading rate of TiNi under localized compressive loads, but much work is directed towards understanding the effect of strain rate on tensile properties. Understanding the superelastic behavior helps to employ superelastic alloys in applications where high impact loading is expected as in bearings and gears. In the present study, it is found that dent resistance of Ti-Ni alloy is not significantly affected by loading rate (within the employed loading conditions). It has also been found that new-generation 60NiTi alloy exhibits superior wear and dent resistance, as well as higher hardness compared to equiatomic TiNi.
文摘Due to their light weight, high corrosion resistance and good heat conductivity, aluminium alloys are used in many industries today. They are suitable for manufacturing many automotive components such as clutch housings. These alloys can be fabricated by powder metallurgy and casting methods, in which porosity is a common feature. The presence of pores is responsible for reducing their strength, ductility and wear resistance. The present study aims to establish an understanding of the tribological behavior of high pressure die cast Al A380M and powder metallurgy synthesized Al 6061. In this study, dry sliding wear behavior of Al A380M and Al 6061 alloys was investigated under low loads (1.5 N – 5 N) against AISI 52100 bearing steel ball using a reciprocating ball-on-flat configuration and frequency of 10 Hz. Wear mechanisms were studied through microscopic examination of the wear tracks. This study revealed that due to combined effect of real area of contact and subsurface cracking, wear rate increased with increasing porosity content. The difference in friction and wear behavior between received Al A380M and Al 6061 is attributed to their hardness differences.
文摘Phage Display technology provides a mechanism for us to make bio-recognition elements on biosensors for detection of Salmonella enterica serovars. In the procedure, the filamentous M13 bacteriophage is used for acquiring peptides that have a high affinity for the target recognition. Our approach in this study was to develop peptide structures in the pIII region of this thread-shaped virus. A phage pIII library was used to perform biopanning for the phage clones to bind the target Salmonella serovars. The clones were bound, washed, eluted and amplified four times. Then, the phage peptides were sequenced tested for specificity using ELISA procedures. In this project to make a biosensor for all relevant Salmonella enterica serovars, we used common LPS salmonellae antigens as targets in the biopanning procedure. This enabled us to have a phage probe specific for all serovars of Salmonella enterica excluding the typhoid organisms. The final phage was then immobilized onto an electromagnetic platform to complete the biosensor, which gives us the real-time ability to measure resonance changes that indicate mass loading. The mass loading is an indication of binding to the target cells. Our current data with an ELISA procedure show the phage probe’s high affinity for salmonellae, very low cross-reactivity with Escherichia coli, Shigella, and no cross-reactivity to Staphylococcus aureus and Listeria monocytogenes. The biosensor with the phage showed that the capture ability for Salmonella serovars is thirty times higher than the control sensor. This biosensor is a candidate for detection of Salmonella in food and other settings.
文摘Due to light weight, high specific strength, high corrosion resistance and good heat transfer ability, aluminium alloys are becoming attractive for critical structural applications. These alloys can be manufactured using powder metallurgy techniques in which porosity is a common characteristic. The presence of pores is responsible for decreasing effective load bearing cross sectional area and inducing stress concentration sites for strain localization and damage, decreasing both strength and ductility. The present study aims to establish a better understanding of the relationship between surface porosity and corresponding wear behavior. In this study, porous specimens were produced using powder metallurgy technique and the extent of wear damage and the type of wear was investigated under low load range of 1.5 - 5 N against AISI 52100 bearing steel ball using a reciprocating ball-on-flat configuration and frequency of 10 Hz. Scanning electron microscopy of the wear tracks and wear debris was carried out to understand wear mechanisms. This study revealed that due to combined effect of high stress intensity and subsurface cracking, wear rate increases with increasing porosity content. The friction and wear behavior of pure Al and Al 6061 as a function of porosity content can be attributed to their hardness and corresponding wear mechanism.
基金supported by the National Science Foundation(ECCS-1807463 and PFI-1718177)UB Blue Sky program+2 种基金funding support from National Cancer Institute(NCI)of the National Institutes of Health(NIH)(R21CA235305)funded by NCI(P30CA16056)the support from National Science Foundation(CBET-1337860),which funds the nanoparticle tracking analysis system(Nano Sight,LM10,Malvern Instruments,Ltd.)。
文摘Subwavelength manipulation of light waves with high precision can enable new and exciting applications in spectroscopy,sensing,and medical imaging.For these applications,miniaturized spectrometers are desirable to enable the on-chip analysis of spectral information.In particular,for imaging-based spectroscopic sensing mechanisms,the key challenge is to determine the spatial-shift information accurately(i.e.,the spatial displacement introduced by wavelength shift or biological or chemical surface binding),which is similar to the challenge presented by super-resolution imaging.Here,we report a unique"rainbow"trapping metasurface for on-chip spectrometers and sensors.Combined with super-resolution image processing,the low-setting 4×optical microscope system resolves a displacement of the resonant position within 35 nm on the plasmonic rainbow trapping metasurface with a tiny area as small as0.002 mm2.This unique feature of the spatial manipulation of efficiently coupled rainbow plasmonic resonances reveals a new platform for miniaturized on-chip spectroscopic analysis with a spectral resolution of 0.032 nm in wavelength shift.Using this low-setting 4×microscope imaging system,we demonstrate a biosensing resolution of 1.92×109exosomes per milliliter for A549-derived exosomes and distinguish between patient samples and healthy controls using exosomal epidermal growth factor receptor(EGFR)expression values,thereby demonstrating a new on-chip sensing system for personalized accurate bio/chemical sensing applications.
文摘This work explores the methodology for micron-scale water droplet contact angle derivation for the warty surface of octocoral sclerites. The calcite-made sclerites of the Red Sea octocoral Dendronephthya hemprichi have been chosen as a model for this study. Water droplet condensation on the sclerites has been in-situ investigated using Quanta 200 FEG （field emission gun） ESEM （environmental scanning electron microscope） under wet environmental conditions. Two different analysis methods of droplet top and side views have been applied to determine the contact angle based on the secondary electron images. The ESEM image analysis for the sclerites indicates that their surface is hydrophilic. The microscopic contact angle is measured to be 45.3°±6.3°. The macroscopic contact angle has been calculated by using the Wenzel model for the surface texturing of the sclerites.
文摘Imaging through scattering medium is challenging but important for different applications.Most advances rely on computational image reconstruction from scattering signals.In these conventional investigations,speckles were always treated as scrambled grainy patterns.Directly seeing through scattering diffusers has never been realized.Here,we report a new strategy to see through random diffusers directly using self-imaging of speckles.By analyzing the physics,a direct observation strategy through scattering media is reported with improved image quality.Using this method,we experimentally demonstrated reconstruction-free real-time imaging of static and moving objects with their actual orientation information under single-wavelength and white light illumination.We also proposed a modified speckle autocorrelation imaging(SAI)method inspired by the self-imaging results.Importantly,our strategy requires no pre-calibration or acquisition of point-spread-function,no active control of wavefronts or complicated equipment,nor iterations or carefully adjusted parameters,paving the way towards rapid and high-quality imaging through scattering diffusers.
基金supported by National Natural Science Foundation of China(T2225019,41925007,62372470,U21A2013,42201415,42022054,42241109,42077156,52121006,42090014,and 42325107)the National Key R&D Programme of China(2022YFF0500)+2 种基金the Youth Innovation Promotion Association CAS(2023112)the Strategic Priority Research Program of CAS(XDA23090303)the RECLAIM Network Plus(EP/W034034/1).
文摘This paper explores the evolution of geoscientific inquiry,tracing the progression from traditional physics-based models to modern data-driven approaches facilitated by significant advancements in artificial intelligence(AI)and data collection techniques.Traditional models,which are grounded in physical and numerical frameworks,provide robust explanations by explicitly reconstructing underlying physical processes.However,their limitations in comprehensively capturing Earth’s complexities and uncertainties pose challenges in optimization and real-world applicability.In contrast,contemporary data-driven models,particularly those utilizing machine learning(ML)and deep learning(DL),leverage extensive geoscience data to glean insights without requiring exhaustive theoretical knowledge.ML techniques have shown promise in addressing Earth science-related questions.Nevertheless,challenges such as data scarcity,computational demands,data privacy concerns,and the“black-box”nature of AI models hinder their seamless integration into geoscience.The integration of physics-based and data-driven methodologies into hybrid models presents an alternative paradigm.These models,which incorporate domain knowledge to guide AI methodologies,demonstrate enhanced efficiency and performance with reduced training data requirements.This review provides a comprehensive overview of geoscientific research paradigms,emphasizing untapped opportunities at the intersection of advanced AI techniques and geoscience.It examines major methodologies,showcases advances in large-scale models,and discusses the challenges and prospects that will shape the future landscape of AI in geoscience.The paper outlines a dynamic field ripe with possibilities,poised to unlock new understandings of Earth’s complexities and further advance geoscience exploration.
