Monitoring odour emisssions from an oil & gas plant: Electronic nose performance testing in the field

This paper focuses on performance testing of electronic noses for environmental odour monitoring in terms of their capability of correctly classifying odours at low odour concentrations. The studied case concerns the realization of an electronic nose network for the continuous monitoring of odour emissions from a crude oil extraction and separation plant. The novelty of the work consists in the fact that performance testing, which is typically carried out in laboratory before installation in the field for environmental odour monitoring outside the plant boundaries, in this case was carried out after installation with the aim of testing the instruments performances in the effective working conditions. This involved the necessity to develop a specific and repeatable procedure to obtain samples at known quality and concentration in the field. Electronic nose performance was evaluated in terms of classification accuracy, which produced satisfactory results towards the considered olfactory classes

Non-carcinogenic occupational exposure risk related to foundry emissions: focus on the workers involved in olfactometric assessments.

The scope of this work is the evaluation of the non-carcinogenic occupational risk related to foundry emissions, focusing on the category of workers involved in olfactometric assessments. Odor pollution from industrial activities such as foundries is a serious environmental concern. Sensorial techniques (e.g. dynamic olfactometry, EN13725:2003) currently represent the preferred method for odor emission characterization. During olfactometric analyses, human assessors are directly exposed to the odor at increasing concentrations, thus requiring the assessment of the associated exposure risk to guarantee workers' safety. This paper presents an investigation aiming to produce an inventory of compounds emitted from foundries together with their odor thresholds and toxicological limits (TLVs), with the final objective to propose a procedure for ensuring workers' safety during olfactometric analyses. Looking at the database resulting from this study, among the >100 compounds emitted by foundries, 8 have a maximum concentration above their TLV. Among those, ammonia, H2S, phenol, toluene and trimethylamine, produce an odor stimulus before they reach a toxic concentration, thus not representing a risk for olfactometric workers. Benzene, formaldehyde and SO2 are identified as the most critical compounds because they may reach toxic concentrations in foundry emissions, and they start being perceived by humans above their TLV. The proposed procedure entails a minimum dilution factor of 27'000 to be applied to odor samples analyzed by olfactometry, which however might result inapplicable in practical cases, thus pointing out the necessity to adopt chemical measurements to investigate specifically the concentration of the most critical compounds identified in this study

A prevalence survey and risk analysis of filariosis in dogs from the Mt. Vesuvius area of southern Italy

A dog microfilariae prevalence and risk factor survey was conducted in 51 contiguous municipalities of the Mt. Vesuvius area (Campania region, southern Italy) in order to add data to the limited epidemiological information available regarding filarial worms in this zone. Between May 1999 and June 2000, blood samples were collected from 351 asymptomatic dogs. Blood samples were examined using a modified Knott's technique and histochemical staining in order to count and identify microfilariae. The results were subjected to statistical analysis and choroplethic municipal maps (MMs) were drawn by a geographical information system (GIS) software. Microfilariae were detected in 63 of the 351 dogs surveyed, constituting a total filarial prevalence of 17.9%. In particular, 56 dogs (15.9%) showed only microfilariae of Dipetalonema reconditum; three dogs (0.8%) only microfilariae of Dirofilaria repens; two dogs (0.6%) microfilariae of both D. reconditum and D. repens and two dogs (0.6%) microfilariae of both Dirofilaria immitis and D. repens. High D. reconditum prevalence was associated with hunting practice, masculine gender and older dogs. There was also a tendency to find high prevalence in dogs sampled in the afternoon. In conclusion, the presence of microfilariae of D. reconditum in 92% of microfilaraemic dogs indicates that this filarial worm was the predominant filarial species in dogs in the Mt. Vesuvius area. In addition, the general trends of the MMs showed that D. immitis and D. repens were present only in a few municipalities, whereas D. reconditum was widely and homogeneously spread throughout the entire study area

Cysticercosis by Taenia pisiformis in Brown Hare (Lepus europaeus) in\ua0Northern Italy: Epidemiologic and pathologic features

In Northern Italy, a hastening of hare population decline was noticeable from 2008. In the same year hunters reported a sudden increase of hares infected by Taenia sp. larvae, whose morphology was consistent with T. pisiformis cysticerci. The aim of the survey was: i)to identify the parasites through morphological features and molecular techniques; ii)to quantify the prevalence and abundance of cysticerci in hunted hares; iii)to describe pathological aspects of parasite-induced lesions; iv)to evaluate the short-term trend of the infection comparing two different hunting seasons; v)to highlight possible relationship between T. pisiformis infection and hare-related variables. In 2013, 2015 the viscera of 54 and 61 hares legally hunted in agro-ecosystems of the Po Plain were collected. Peritoneum, liver and lungs were examined for cysticercosis; abundance was estimated counting superficial parasites in liver; parasites were microscopically identified by shape and measure of both large and small hooks. One cysticercus from each hare was analized by a PCR targeting Taeniid species and then sequenced. Frozen liver, lungs and gastrointestinal peritoneum were macroscopically observed and, after thawing, representative samples from the available organs were collected for histologic examination to verify parasitic cysts and the subsequent damage of the involved organs. Sex, weight and age class of the animals were recorded. Generalized linear models were used for statistical analysis. T. pisiformis was isolated in 8 hares in 2013 (prevalence 14.8%; abundance range: 0-400; mean abundance 17.8) and in 2 hares in 2015 (prevalence 3.28%; abundance range: 0-180; mean abundance 3.22). Identification was confirmed morphologically and by PCR. The DNA sequencing confirmed T. pisiformis in all samples. The sequences were all identical each-other. Infection was significantly related with adult age class, sampling year and low full-weight. Epidemiological and pathological pattern suggest both a possible role on host population health and a tendency toward host-parasite equilibrium

Electronic noses for environmental monitoring applications

Electronic nose applications in environmental monitoring are nowadays of great interest, because of the instruments’ proven capability of recognizing and discriminating between a variety of different gases and odors using just a small number of sensors. Such applications in the environmental field include analysis of parameters relating to environmental quality, process control, and verification of efficiency of odor control systems. This article reviews the findings of recent scientific studies in this field, with particular focus on the abovementioned applications. In general, these studies prove that electronic noses are mostly suitable for the different applications reported, especially if the instruments are specifically developed and fine-tuned. As a general rule, literature studies also discuss the critical aspects connected with the different possible uses, as well as research regarding the development of effective solutions. However, currently the main limit to the diffusion of electronic noses as environmental monitoring tools is their complexity and the lack of specific regulation for their standardization, as their use entails a large number of degrees of freedom, regarding for instance the training and the data processing procedures

A Dual-phase Xenon TPC for Scintillation and Ionisation Yield Measurements in Liquid Xenon

A small-scale, two-phase (liquid/gas) xenon time projection chamber (Xurich II) was designed, constructed and is under operation at the University of Zurich. Its main purpose is to investigate the microphysics of particle interactions in liquid xenon at energies below 50 keV, which are relevant for rare event searches using xenon as target material. Here we describe in detail the detector, its associated infrastructure, and the signal identification algorithm developed for processing and analysing the data. We present the first characterisation of the new instrument with calibration data from an internal 83m-Kr source. The zero-field light yield is 15.0 and 14.0 photoelectrons/keV at 9.4 keV and 32.1 keV, respectively, and the corresponding values at an electron drift field of 1 kV/cm are 10.8 and 7.9 photoelectrons/keV. The charge yields at these energies are 28 and 31 electrons/keV, with the proportional scintillation yield of 24 photoelectrons per one electron extracted into the gas phase, and an electron lifetime of 200 $\mu$s. The relative energy resolution, $\sigma/E$, is 11.9 % and 5.8 % at 9.4 keV and 32.1 keV, respectively using a linear combination of the scintillation and ionisation signals. We conclude with measurements of the electron drift velocity at various electric fields, and compare these to literature values.Comment: 11 pages, 14 figure