ZnO nanotetrapods have recently been exploited for the realization of high-sensitivity gas sensors, but they are affected by the typical drawbacks of metal-oxides, i.e., poor selectivity and a relatively high working temperature. On the other hand, it has been also demonstrated that the combined use of nanostructured metal oxides and organic molecules can improve the gas sensing performance sen...

A new sensor for methane and carbon dioxide concentration measurements in biogas plants is presented. LEDs in the mid infrared spectral region are implemented as low cost light source. The combination of quartz-enhanced photoacoustic spectroscopy with an absorption path leads to a sensor setup suitable for the harsh application environment. The sensor system contains an electronics unit and the...

In the present study, UV light induced desorption of nitrogen dioxide (NO2) on pristine graphene based gas sensor is used to improve the sensing performance. Compared to the sample without UV light exposure, the response is 12%, 18% and 21% for NO2 concentrations of 1, 3 and 5 ppm. In addition, the recovery could be speeded up by UV irradiation. The sensor shows good behavior of repeatability w...

A trace gas sensor based on quartz-enhanced photoacoustic spectroscopy with a quantum cascade laser operating at 4.55 μm as an excitation source was developed. The sensor performance was evaluated for the detection of N2O and CO. A noise-equivalent (1σ) sensitivity of 4 ppbv N2O with 3 s response time to (1−1/e) of the steady-state level was demonstrated. The influence of the relevant energy tr...

Linear membrane-based gas sensors that can be advantageously applied for the measurement of a single gas component in large heterogeneous systems, e.g., for representative determination of CO₂ in the subsurface, can be designed depending on the properties of the observation object. A resulting disadvantage is that the permeation-based sensor response depends on operating conditions, the individ...

Exhaled nitric oxide (NO) is an important biomarker in asthma and other respiratory disorders. The optical performance of a NOCO(2) sensor employing integrated cavity output spectroscopy (ICOS) with a quantum cascade laser operating at 5.22 microm capable of real-time NO and CO(2) measurements in a single breath cycle is reported. A NO noise-equivalent concentration of 0.4 ppb within a 1-sec in...

Fluorine-containing polymers have a number of valuable physical and chemical properties, such as high chemical and heat resistance, high mechanical strength and highly selective gas separation characteristics. One of the ways to produce fluoropolymer membranes is through surface fluorination. The modifcation of commercial polymers with membrane properties, poly(4-methyl-1...

Physical properties are crucial to gelatin utilization and the physical properties are determined by structure. Therefore, it is important to investigate the nanostructure and physical properties of gelatin over the full range of concentrations which are widely applied in research and industry. Nanostructure of gelatin can be investigated by atomic force microscopy (AFM). However, it is hard to...

Unpublished AIChE shall not be responsible for statements or opinions contained in papers or printed in its publications. Abstract This paper describes a novel calorimeter applicable for the simultaneous measurement of adsorption isotherms and the corresponding heats of adsorption. The calorimeter is based on a new metrological principle as a gas surrounding the adsorption vessel containing the...