Analysis of the market structure of long-distance transport vehicles in the context of retrofitting diesel engines with modern dual-fuel systems.

The demands placed on vehicles are constantly increasing. European legislation has forced commercial vehicle manufacturers to develop ever more powerful and dynamic engines with low fuel consumption. With the appearance of exhaust gas standards, truck manufacturers realized that it was necessary to improve the fuel supply system so that the combustion process was more efficient. To achieve this the fuel injected into the cylinders had to be finer in order to mix more easily with air. High-pressure unit injection systems have proved to be a good and reliable solution. They are also relatively cheap to produce and less prone to fuel contamination. Many years and millions of failure-free kilometers traveled on unit injectors effectively distracted some users and producers from the Common Rail system. Exhaust gas standards and increasing consumer expectations forced manufacturers to take another step in their development, i.e. the need for more precise fuel injection control. The injectors had to run faster in order to carry out the initiation dose, the actual injection and the extra injection. All these modifications make diesel engines in commercial vehicles such as tractor units much more powerful. They also allow for cooperation with aftermarket dual-fuel CNG-ON and LPG-ON installations. Dual-fuel solutions are perhaps another step towards reducing emissions, and thanks to reduced tolls, they are becoming a real alternative to conventional fuel-powered tractor units. This work focuses on the structure of the truck tractor market in terms of selecting cars used for the use of a non-factory dual-fuel CNG-ON installation.

A Bio-Fluorometric Acetone Gas Imaging System for the Dynamic Analysis of Lipid Metabolism in Human Breath

We constructed an imaging system to measure the concentration of acetone gas by acetone reduction using secondary alcohol dehydrogenase (S-ADH). Reduced nicotinamide adenine dinucleotide (NADH) was used as an electron donor, and acetone was imaged by fluorescence detection of the decrease in the autofluorescence of NADH. In this system, S-ADH–immobilized membranes wetted with buffer solution containing NADH were placed in a dark box, and UV-LED excitation sheets and a high-sensitivity camera were installed on both sides of the optical axis to enable loading of acetone gas. A hydrophilic polytetrafluoroethylene (H-PTFE) membrane with low autofluorescence was used as a substrate, and honeycomb-like through-hole structures were fabricated using a CO2 laser device. After loading the enzyme membrane with acetone gas standards, a decrease in fluorescence intensity was observed in accordance with the concentration of acetone gas. The degree of decrease in fluorescence intensity was calculated using image analysis software; it was possible to quantify acetone gas at concentrations of 50–2000 ppb, a range that includes the exhaled breath concentration of acetone in healthy subjects. We applied this imaging system to measure the acetone gas in the air exhaled by a healthy individual during fasting.

Long term stability of dynamic reference systems for NO2 atmospheric monitoring

<p>The long-term monitoring of reactive gases, such as NO<sub>2</sub>, provides significant challenges for the development of gas standards that can demonstrate fit-for-purpose stability and accuracy.  Over the last fifteen years the BIPM’s primary gas facility for the dynamic production of mixtures of nitrogen dioxide in nitrogen, operating over the range (1 μmol/mol to 15 μmol/mol) has been shown to operate with a relative standards uncertainty of 0.4%. The system is based on continuous weighing of a permeation tube and on the accurate impurity quantification and correction of the gas mixtures using FT-IR.</p><p>The operation of the system has been demonstrated in two international comparisons organized by the CCQM Working Group on Gas Analysis (CCQM-GAWG), in 2009 and 2018, with the former demonstrating the requirement to correct for HNO<sub>3</sub> impurities in gas standards produced in cylinders, and the more recent, the potential for non-linear decay in NO<sub>2</sub> concentration in gas cylinder standards in the first 100 to 150 days following their production.</p><p>The CCQM-K74 (2009/2010) was organized, with all cylinders prepared by the one NMI (VSL) with the same surface treatment and characterized for stability and with reference values provided by the BIPM dynamic reference facility. The initial comparison identified small decay rates in the circulated standards, accounted for by the addition of an uncertainty to the reference value, and calculated to have been no more than 0.1 nmol/mol per day loss of NO<sub>2</sub>. However, the 2009 comparison did not examine standards maintained by individual participating institutes directly. The protocol of the CCQM-K74.2018 comparison, was modified so that the standards prepared by participating institutes (two per participant), were all directly measured at the BIPM against its dynamic reference facility. The modified protocol, although technically more challenging, has allowed the different decay rates in different cylinder preparations from different institutes to be identified, as well as the time dependence of these days rates.</p><p>The work has highlighted the challenges in NO<sub>2</sub> standard development, and that fit-for-purpose standards can be obtained following appropriate protocols. Further development of these protocols is the focus of a number of research programmes, for example  METNO2 and MetroPEMS projects within the EMPIR programmes. Further activities at the BIPM facility are focused on validating the performance of NO<sub>2</sub> dynamic reference systems below 1 μmol/mol and into the nmol/mol range, with the comparison of different dynamic reference systems, in support of future international comparisons and knowledge transfer activities.</p>

Casing failure identification of long-abandoned geothermal wells in Field Dieng, Indonesia

Integrity issues create challenges for maintaining the production of mature geothermal wells. Such problems are likely to occur in wells designed according to oil and gas standards, without considering the extreme geothermal environment. PT Geo Dipa Energi as the operator of the Dieng geothermal field, one of the longest operated in Indonesia, has experienced this difficulty since acquiring the field. Almost half of the production wells have been abandoned because of casing issues. To increase production, the operator plans to reactivate wells that have been previously abandoned. An initial study was performed to assess the technical feasibility of reactivating wells at Dieng; it included the development of a well assessment methodology including casing design, comprising historical data analysis, identification of well problems, and investigation of well integrity. The study focused on the identification and characterization of two abandoned wells, HCE9B and HCE28B, current casing conditions, limitations, and challenges to perform a well intervention and workover which is realistic, measurable, economic, and technically feasible. The result of this study will be applicable for casing design for future wells.

Stability of gaseous volatile organic compounds contained in gas cylinders with different internal wall treatments

Measurements of volatile organic compounds (VOCs) have been ongoing for decades to track growth rates and assist in curbing emissions of these compounds into the atmosphere. To accurately establish mole fraction trends and assess the role of these gas-phase compounds in atmospheric chemistry it is essential to have good calibration standards. A necessity and precursor to accurate VOC gas standards are the gas cylinders and the internal wall treatments that aid in maintaining the stability of the mixtures over long periods of time, measured in years. This paper will discuss the stability of VOC gas mixtures in different types of gas cylinders and internal wall treatments. Stability data will be given for 85 VOCs studied in gas mixtures by National Metrology Institutes and other agency laboratories. This evaluation of cylinder treatment materials is the outcome of an activity of the VOC Expert Group within the framework of the World Meteorological Organization (WMO) Global Atmospheric Watch (GAW) program.

Use of FTIR spectroscopy for the measurement of CO2 carbon stable isotope ratios

Carbon dioxide (CO2) is one of the most important long-lived anthropogenic greenhouse gases. Ocean, land and biosphere contribute to take up CO2 emissions, but approximately half of fossil fuel CO2 accumulates in the atmosphere. The study of isotopic composition of CO2 can give useful information for assessing and quantifying the uptake of CO2 in the environmental compartments, as well as for distinguishing natural from anthropogenic carbon in the atmosphere. In this work, an activity for the development of a Fourier Transform Infrared spectroscopy (FTIR) based method for δ13C-CO2 determination in CO2 in air mixtures is presented. The FTIR can be calibrated by a classical approach based on primary calibration gas standards, but an alternative calibration can be based on the generation of synthetic spectra, by means of radiative transfer calculation codes such as the Multiple Atmospheric Layer Transmission (MALT University of Wollongong, Australia). Another software (B-FOS) developed at the Bureau International des Poids et Mesures (BIPM) allows to interface MALT and the FTIR management software. This calibration approach is fast and reliable and can be used when the classical calibration based on reference gas mixtures might be demanding. The uncertainty obtained for δ13C-CO2 measurements is around 0.1 ‰, at a nominal CO2 mole fraction of 400 μmol mol-1 in air.