496 research outputs found
Preliminary trial application of biological desulfonation in anaerobic digestors from pig farms
This paper describes preliminary tests carried out in treatment plants serving two different pig farms in Northern Italy, in order to assess the feasibility of implementing biological sulphur removal from biogas produced by anaerobic digestion processes. This normally consists of mixture of CH4, CO2, and other gases; in the presence of sulphur, H2S is also formed, which must be removed prior to the gas use in thermal engines, to avoid corrosion phenomena. Sulphur removal in the plants considered is currently achieved by means of chemical filtration, however this adds costs to the process and generates a waste to be disposed of. As a process alternative, biological sulphur removal by means of Thiobacillus sp. bacteria can also be obtained. The process,
however, requires specific conditions in the gas stream in order to achieve high process efficiency. Biological desulfonation was applied on a trial basis in two biogas production plants, with different layouts, and encouraging results. These confirms the validity of the process, although the maximum foreseen removal efficiencies were not achieved due to structural drawbacks of the tested facilities, that will have to be revamped in order to apply this process with full satisfaction and effectiveness
Environmental and economic benefits from the phase-out of residential oil heating: A study from the Aosta Valley region (Italy)
Although its use is declining, oil heating is still used in areas not covered by the methane grid. Oil heating is becoming more and more expensive, requires frequent tank refill operations, and has high emissions of greenhouse gas (GHG) and air pollutants such as SOx. In addition, spills from oil underground storage tanks (USTs) represent a serious environmental threat to soil and groundwater quality. In this paper, we present a comprehensive analysis on technical alternatives to oil heating with reference to the Aosta Valley (NW Italy), where this fuel is still often used and numerous UST spills have been reported in the last 20 years. We assess operational issues, GHG and pollutant emissions, and unit costs of the heat produced for several techniques: LPG boilers, wood boilers (logs, chips, pellets) and heat pumps (air-source, geothermal closed-loop and open-loop systems). We examine the investment to implement such solutions in two typical cases, a detached house and a block of flats, deriving payback times of about 3â8 years. Wood log boilers turn out to be the most economically convenient solutions; however, heat pumps provide several benefits from the operational and environmental points of view. In addition, including solar thermal panels for domestic hot water or a photovoltaic plant would have payback times of about 6â9 years. The results highlight the economic feasibility and the multiple benefits of a rapid phase-out of oil heating in Italy
Extensive carrier testing and CF birth prevalence: evidence for a negative correlation
Aim of the study was to evaluate if extensive CF carrier testing may be connected
with the progressive decrease of CF birth incidence recorded in North Eastern Italy.
From 1993 to 2007 an average 52,000 newborns per year underwent Neonatal
Screening (NS), and 198 newborns with CF were detected (1/3937). A time related
contraction in birth prevalence was confirmed, with an average annual percent
decrease of 0.15 per 10,000 neonates (Poisson regression analysis p 0.003). In
the NS area two sections were identified: the Western Region (WR), where CF
carrier testing is not offered to couples from the general population, and the
Eastern Region (ER), where CF carrier testing is widely offered to couples from
the general population. In ER from 1995 to 2007 such testing practice has been
steadily expanding, with a total of 87,721 CF carrier tests performed, 3460 carriers
identified, and 238 carrier couples detected (data collection in progress). The
prevalence of CF decreased by time (p<0.001) but the rate of decrease was more
enhanced in ER as suggested by the existence of a statistically significant (p = 0.014)
interaction term between time and region in the Poisson regression model. The
overall negative trend in North Eastern Italy is due to a contraction of CF births
in its Eastern part. In ER a negative correlation was found between CF incidence
and the number of carrier tests (p 0.012). Prenatal diagnosis data collection is in
progress. These data support the hypothesis that carrier screening may modify the
incidence of CF
Hollow-Core Fiber-Based Biosensor: A Platform for Lab-in-Fiber Optical Biosensors for DNA Detection
In this paper, a novel platform for lab-in-fiber-based biosensors is studied. Hollow-core tube lattice fibers (HC-TLFs) are proposed as a label-free biosensor for the detection of DNA molecules. The particular light-guiding mechanism makes them a highly sensitive tool. Their transmission spectrum is featured by alternations of high and low transmittance at wavelength regions whose values depend on the thickness of the microstructured web composing the cladding around the hollow core. In order to achieve DNA detection by using these fibers, an internal chemical functionalization process of the fiber has been performed in five steps in order to link specific peptide nucleic acid (PNA) probes, then the functionalized fiber was used for a three-step assay. When a solution containing a particular DNA sequence is made to flow through the HC of the TLF in an âoptofluidicâ format, a bio-layer is formed on the cladding surfaces causing a red-shift of the fiber transmission spectrum. By comparing the fiber transmission spectra before and after the flowing it is possible to identify the eventual formation of the layer and, therefore, the presence or not of a particular DNA sequence in the solution
Long maximal incremental tests accurately assess aerobic fitness in class II and III obese men.
This study aimed to compare two different maximal incremental tests with different time durations [a maximal incremental ramp test with a short time duration (8-12 min) (STest) and a maximal incremental test with a longer time duration (20-25 min) (LTest)] to investigate whether an LTest accurately assesses aerobic fitness in class II and III obese men. Twenty obese men (BMIâ„35 kg.m-2) without secondary pathologies (mean±SE; 36.7±1.9 yr; 41.8±0.7 kg*m-2) completed an STest (warm-up: 40 W; increment: 20 W*min-1) and an LTest [warm-up: 20% of the peak power output (PPO) reached during the STest; increment: 10% PPO every 5 min until 70% PPO was reached or until the respiratory exchange ratio reached 1.0, followed by 15 W.min-1 until exhaustion] on a cycle-ergometer to assess the peak oxygen uptake [Formula: see text] and peak heart rate (HRpeak) of each test. There were no significant differences in [Formula: see text] (STest: 3.1±0.1 L*min-1; LTest: 3.0±0.1 L*min-1) and HRpeak (STest: 174±4 bpm; LTest: 173±4 bpm) between the two tests. Bland-Altman plot analyses showed good agreement and Pearson product-moment and intra-class correlation coefficients showed a strong correlation between [Formula: see text] (r=0.81 for both; pâ€0.001) and HRpeak (r=0.95 for both; pâ€0.001) during both tests. [Formula: see text] and HRpeak assessments were not compromised by test duration in class II and III obese men. Therefore, we suggest that the LTest is a feasible test that accurately assesses aerobic fitness and may allow for the exercise intensity prescription and individualization that will lead to improved therapeutic approaches in treating obesity and severe obesity
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