A5083092404- Advanced Combustion Engine Technologies
- Photoacoustic and Ultrasonic Imaging
- Atmospheric chemistry and aerosols
- Thermography and Photoacoustic Techniques
- Combustion and flame dynamics
- Combustion and Detonation Processes
- Optical Coherence Tomography Applications
- Nanoplatforms for cancer theranostics
- Additive Manufacturing and 3D Printing Technologies
- Additive Manufacturing Materials and Processes
- Air Quality Monitoring and Forecasting
- Catalytic Processes in Materials Science
- Advanced X-ray and CT Imaging
- Gold and Silver Nanoparticles Synthesis and Applications
- Laser Material Processing Techniques
- Laser Applications in Dentistry and Medicine
- Welding Techniques and Residual Stresses
- Optical Imaging and Spectroscopy Techniques
- Spectroscopy and Laser Applications
- Air Quality and Health Impacts
- Gas Sensing Nanomaterials and Sensors
- Water Quality Monitoring and Analysis
- Advanced Photocatalysis Techniques
- Copper-based nanomaterials and applications
- Refrigeration and Air Conditioning Technologies
Universität der Bundeswehr München
2022-2024
Shandong University of Science and Technology
2024
Technical University of Munich
2014-2022
Helmholtz Zentrum München
2013-2016
Stanford University
2008-2015
Temper (United States)
2013
Real‐Time Optoacoustic Monitoring of RF Ablation Introduction Due to lack reliable imaging contrast from catheter radiofrequency ablation (RFA) lesions, the vast majority current procedures rely on indirect indicators activity, resulting in a significant number arrhythmia reoccurrences after RFA and need for repeat surgeries. The objective this work is develop an accurate method on‐the‐fly assessment durability size lesions formed during procedures. Method Results Radiofrequency freshly...
Abstract Rate constants for the overall reactions of OH with n -pentane, -heptane, and -nonane were measured in shock tube experiments behind reflected waves. Narrow-linewidth laser absorption by at 306.7 nm was used pseudo first-order temperatures between 869 to 1364 K. tert -Butyl hydroperoxide (TBHP) as precursor. Experiments also performed study kinetics TBHP decomposition resulting product chemistry, an accurate mechanism describing precursor chemistry effects developed model...
Non-contact optoacoustic imaging employing raster-scanning of a spherically focused air-coupled ultrasound transducer is showcased herein. Optoacoustic excitation with laser fluence within the maximal permissible human exposure limits in visible and near-infrared spectra applied to objects characteristic dimensions smaller than 1 mm absorption properties representative whole blood at wavelengths, these signals are shown be detectable without contact sample using an reasonable signal...
Gold nanoparticles can be used as an exogenous contrast agent for biomedical photoacoustic (PA) imaging. The generation of PA signals in monodispersed gold nanosphere suspensions (diameters 20–150 nm) from pulsed-laser excitation (5 ns pulse width, wavelength 532 was investigated experimentally and compared to measured solutions a homogeneous molecular absorber. signal amplitude found increase linearly with fluence the absorber nanospheres up 80 nm diameter. By contrast, quadratically...
Hot electrons generated by photoinduced plasmon decay from a plasmonic metal surface can reduce 4-nitrothiophenol (4-NTP) to 4-aminothiophenol (4-ATP). Compared the reduction with reducing agent such as sodium borohydride, surface-enhanced Raman scattering (SERS) measurements were performed here elucidate complex molecular mechanism of in presence halide ions and hydrogen ions. The SERS using simply prepared silver film (AgPF), which enables monitoring reaction under different conditions at...
The rate constant for the overall reaction OH + 1-butanol → products was determined in temperature range 900 to 1200 K from measurements of concentration time histories reflected shock wave experiments tert-butyl hydroperoxide (TBHP) as a fast source radicals with excess. Narrow-linewidth laser absorption employed quantitative measurement. A detailed kinetic mechanism constructed that includes updated constants and TBHP kinetics influence near-first-order decay under present experimental...
Silica-coated gold nanoparticles are commonly employed in biomedical photoacoustic (PA) imaging applications. We investigate theoretically and experimentally the PA signal generation by silica-coated nanospheres water. Our theoretical model considers thermoelastic expansion long-pulse illumination regime, signals determined based on a semi-analytical solution to thermal diffusion equations finite-difference time domain (FDTD) equations. Both influence of interfacial (Kapitza) resistance at...
This work presents the first direct experimental study of rate constant for reaction OH with iso-butanol (2-methyl-1-propanol) at temperatures from 907 to 1147 K near-atmospheric pressures. time-histories were measured behind reflected shock waves using a narrow-linewidth laser absorption method during reactions dilute mixtures tert-butylhydroperoxide (as fast source OH) in excess. The title reaction's overall (OH + →(k(overall)) all products) minus β-radical-producing channel →(k(β))...
The overall rate constant for the reaction tert-butanol + OH → products was determined experimentally behind reflected shock waves by using 18O-substituted (tert-butan18ol) and tert-butyl hydroperoxide (TBHP) as a fast source of 16OH. data were acquired from 900 to 1200 K near 1.1 atm are best fit Arrhenius expression 1.24 × 10–10 exp(−2501/T [K]) cm3 molecule–1 s–1. title include tert-C4H8OH radical that is known have two major β-scission decomposition channels, one which produces radicals....
The overall rate constant for the reaction ethanol + OH → products was determined experimentally from 900 to 1270 K behind reflected shock waves. Ethan(18)ol utilized these measurements in order avoid recycling of radicals following H-atom abstraction at β-site ethanol. Similar experiments were also performed with unlabeled ethan(16)ol infer that excludes reactivity β-site. two data sets used directly branching ratio Experimental current study and previous low-temperature studies are best...
Lack of sensory feedback during laser surgery prevents surgeons from discerning the exact location incision, which increases duration and complexity treatment. In this study we demonstrate a new method for monitoring ablation procedures. Real‐time tracking three dimensional (3D) lesion profile is accomplished by detection shock waves emanating spot subsequent reconstruction incision using time‐of‐flight data obtained multiple acoustic detectors. Here, incisions up to 9 mm in depth, created...
Current legislations typically characterize systems of aerosols, such as from vehicle exhaust, primarily by number concentration and size distributions. While potential health threats have a dependence on the particle size, chemical composition particles, including volatile semi-volatile components adsorbed onto nonvolatile cores present at roadside urban settings, is important in understanding impact exhaust particles health. To date, only tools suitable for an online in-depth aerosol...
The overall rate constant for the reaction of OH with sec-butanol [CH(3)CH(OH)CH(2)CH(3)] was determined from measurements near-first-order decay in shock-heated mixtures tert-butylhydroperoxide (as a fast source OH) excess. Three kinetic mechanisms literature describing combustion were used to examine sensitivity determination secondary kinetics. can be described by Arrhenius expression 6.97 × 10(-11) exp(-1550/T[K]) cm(3) molecule(-1) s(-1), valid over temperature range 888-1178 K....
The photoacoustic (PA) signal amplitude measured in gold nanosphere suspensions has been shown to increase nonlinearly with the incident excitation fluence. In this work, effect is exploited recover spatial distribution of nanoparticles tomographic 3D images against background contrast provided by absorbers that exhibit a linear relationship between PA and Serial tissue phantom containing nanospheres tissue-mimicking absorber were acquired. By assessing linearity intensity voxel voxel,...
Abstract Laser‐based powder bed fusion (PBF‐LB) has gained prominence in the realm of additive manufacturing metals. This technique utilizes a laser beam to consolidate layers, which inherently introduces high thermal gradients and rapid cooling rates. results characteristic process effects, including inhomogeneities, surface roughness, anisotropy, residual stress, play pivotal role altering fatigue properties manufactured components. paper presents tests involving samples AlSi10Mg using...
Cold-start emissions of the sustainable alternative diesel fuel OME are predominantly NO x , formaldehyde, formic acid and unburned OME. Electrical heating in combination with dosing is an effective method for after-treatment system heating.
The photoacoustic signal generated from specific gold nanoparticles increases nonlinearly with respect to fluence. We demonstrate experimentally that this nonlinear behavior can be quenched a particle coating, and present theoretical analysis explain behavior. This effect has the potential developed into photoacoustic-based biochemical sensor.
Abstract The maximum size of additively manufactured (AM) components is restricted due to the confined building space manufacturing machines. Component separation and subsequent joining can be an effective way larger using AM processes. For components, adhesive bonding provides great potential for not constraining adherend’s geometry, as long still applied surfaces adherends. This work investigates effectiveness applicability inner channels improve application. A circular single lap joint...
Current radiofrequency cardiac ablation procedures lack real-time lesion monitoring guidance, limiting the reliability and efficacy of treatment. The objective this work is to demonstrate that optoacoustic imaging can be applied develop a diagnostic technique applicable for arrhythmia treatment with capabilities ablated size geometry. We an method using 256-detector probe pulsed-laser illumination in infrared wavelength range during excised porcine myocardial tissue samples. This results...
Joining of metal parts manufactured by laser beam powder bed fusion (PBF-LB/M) eliminates the inherent size restriction this additive manufacturing process and reduces effort. Adhesive bonding presents great potential for joining PBF-LB/M parts, as there are no constraints on shape connecting surfaces, long adhesive can be applied. The freedom design underlying enables construction inner channels in which facilitate application. injected into a single inlet exterior part directed through...
A physical model for the precooler in a SABRE engine was established, and both influencing degrees mechanisms of inlet conditions geometric parameters on flow-heat transfer characteristics unit were explored through parametric analysis sensitivity analysis, respectively. The results demonstrated that air massflow rate exerted greatest influence total pressure loss coefficient due to its significant impact airflow velocity thermal loading. temperature had dominant effect heat rate, owing...
The synthesis of nanomaterials through pulsed-laser ablation a bulk solids can be applied for the generation reference aerosols applications in aerosol science, where no reliable source samples currently exists. To develop generators based on laser that are capable with well-defined properties, more data is needed how properties depend parameters, such as wavelength, power, repetition rate, and surrounding gas. We present an device from nanosecond pulsed Nd:YAG report initial our systematic...