Compact High-Velocity Atmospheric Pressure Dielectric Barrier Plasma Jet in Ambient Air

In this paper,a non-thermal atmospheric pressure plasma jet at high streaming velocity operating with ambient air is highlighted.In the present technological approach,the employment of air poses a significant challenge.The high oxygen concentration in air results in a reduced concentration of reactive species in combination with a short species lifetime.The plasma jet assembly presented here contains a special dielectric barrier with a high secondary emission coefficient.In this way,the electron density and in turn the density of reactive species is increased.In addition,the plasma jet assembly is equipped with a short electrode.This leads to a higher voltage across the discharge gap and in turn to an increased density of reactive plasma species.The plasma jet is formed within and emitted by a small conical nozzle.A high-speed gas flow with gas velocity of 340 m/s was achieved at the end of the nozzle.In the jet the concentration of toxic and unwanted neutral plasma species like O3 or NOx is significantly reduced because of the shorter residence time within the plasma.The range of short-lived active plasma species is in turn considerably enhanced.The jet efficiency and action range measured through the oxidation of a test surface were determined by measuring the increase of surface tension of a polypropylene substrate via contact angle measurements after plasma treatment.Numerical modeling of the plasma plume indicates that oxygen atoms are in fact the main active species in the plasma plume.

Mass Spectrometric Imaging of Gold Nanolayer Coated Latent Fingermarks: Deciphering Overlapping Features by Statistical Analysis

Overlapping latent fingermarks constitute a serious challenge to database related recognition and matching algorithms in biometry, forensic and crime scene investigations. Mass spectrometry imaging (MSI) is a powerful tool for deciphering and analyzing overlapping fingermarks based on the individual chemical information of each deposit. Fingermark MSI in practice still requires a subjective judgment of an MSI expert, such that rapid analysis, automation, standardization, and a quantitative evaluation of the complete detection and separation process of overlapped fingermarks from MSI data sets is the ultimate goal and will be necessary to become an accepted process in criminal investigations and law enforcement. Here we investigated the feasibility and efficiency of different statistical approaches for the separation of overlapped latent fingermarks based on MSI data. Entropy analysis of generated m/z-images was used to evaluate the results obtained from the statistical analysis. Furthermore, we demonstrate and discuss the opportunity to reconstitute and separate overlapping fingermarks by discrete scanning at selected x,y-positions defined from a previous image analysis using a more simple schema based on visible and therefore optical distinguishable overlapped ink-based fingermarks. The overlapped latent fingermarks were developed by rapid gold sputter coating and analyzed by laser based MSI, without (organic) matrix preparation. Latent finger marks can be transferred from the substrate/surface with and conserved on a soft gold sputtered soft membrane at low temperatures.

Removal of endocrine disrupting chemicals from water through urethane functionalization of microfiltration membranes via electron beam irradiation

Polyethersulphone(PES)membranes modified with urethane functional groups were prepared through an interfacial reaction using electron beam irradiation.The removal of eight endocrine disrupting chemicals(EDCs)was studied using both pristine and functionalized PES membranes.The prepared membranes underwent characterization using several techniques,including attenuated total reflectance-Fourier transform infrared(ATR-FTIR)spectroscopy,scanning electron microscopy,contact angle analysis,and measurements of pure water flux.Furthermore,dynamic adsorption experiments were conducted to evaluate the adsorption mechanism of the prepared membrane toward the eight EDCs.The urethane functionalized membranes were hydrophilic(52°contact angle)and maintained a high permeate flux(26000 L/h m^(2) bar)throughout the filtration process.Dynamic adsorption results demonstrated that the introduction of urethane functional groups on the membranes significantly enhanced the removal efficiency of 17β-estradiol,estriol,bisphenol A,estrone,ethinylestradiol,and equilin.The adsorption loading of 17β-estradiol on the functionalized PES membrane was 6.7±0.7 mg/m^(2),exhibiting a 5-fold increase compared to the unmodified PES membrane.The membranes were successfully regenerated and reused for three adsorption cycles without experiencing any loss of adsorption capacity.