37 research outputs found
Energy Efficiency and System Performance of R-454C, R-449A, and R-744 in Food Retail Refrigeration Systems: A Comparison
No full textReduced energy use and increased energy efficiency are essential for decarbonization and sustainable development. The food cold chain is a crucial infrastructure with high energy consumption and rising demand. A careful selection of technology used in food retail systems could result in long-term energy savings, functionality, ease of maintenance, and high energy efficiency. In this work, the layout of an existing store has been used to model the commercial refrigeration system for three Low GWP refrigerants: R-454C, R-449A, and R-744. Energy usage and seasonal efficiency have been examined for two locations in Europe, representing mild and hot ambient temperatures. Results show that systems based on R-454C and R-449A perform significantly better than R-744 architectures, improving sCOP of up to +8.5% and +13.6% respectively, with a simpler equipment design. This suggests that a careful assessment is required to select the most appropriate refrigerant for each store size and climatic condition
Correction: Six minute walk distance and reference values in healthy Italian children: A cross-sectional study (PLoS ONE (2018) 13, 10 (e0205792) DOI:10.1371/journal.pone.0205792)
No full textThe affiliation for the fifth author is incorrect. Roberto Codella is not affiliated with #4–8 but with #4 and #8: School of Exercise Sciences, Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy and Metabolism Research Center, IRCCS Policlinico San Donato, San Donato Milanese, Italy
Monitoraggio in campo e modellizzazione di una pompa di calore a compressione di vapore acqua-acqua
No full textLAUREA MAGISTRALENell’ambito di questa tesi viene presentato il lavoro svolto sul progetto RELAB: “Monitoraggio in campo di pompe di calore” e si approfondisce lo studio di un impianto con pompa di calore acqua-acqua presentando un modello di supporto all’analisi del suo funzionamento in condizioni stazionarie.
Il contributo allo sviluppo del sistema di monitoraggio è partito dall’analisi dei dati monitorati per la verifica della corretta installazione dei misuratori e si è concentrato sull’implementazione di filtri di validazione e di elaborazione dei dati raccolti.
Il modello della pompa di calore è stato implementato in MATLAB e simula il comportamento in condizioni stazionarie della macchina in funzionamento ai carichi parziali. Dai dati ottenuti dalle simulazioni è stato possibile interpretare in maniera più accurata i risultati del monitoraggio.This thesis presents the work done on the project RELAB: “Monitoring of heat pumps systems”. A water-to-water heat pump is studied in details and a model is used to simulate its behaviour in steady state and partial load conditions. The results of the simulations are used to support the analysis of the monitored data.
As for the monitoring systems, a careful study of the first available data has been done to verify the correct installation of the measuring devices. Some validation and elaboration filters have been created to prepare data for performance evaluations.
The heat pump model has been implemented in MATLAB and it has been used to simulate the behaviour of the heat pump in partial load conditions. The results of the simulations have been used to study the data obtained in the monitoring process
Investigating the generalizability of Economic Evaluations conducted in Italy: a critical review
No full textbstract: Aim. To assess the methodological quality of Italian HEEs and their generalizability or
transferability to different settings.
Methods. A literature search was performed on Pubmed search engine to identify trial-based, non-
experimental prospective studies or model-based full economic evaluations, carried out in Italy from
1995 to 2013. The studies were randomly assigned to four reviewers who applied a detailed checklist
to assess the generalizability and the quality of reporting. The review process followed a three-step
blinded procedure. The reviewers who carried out the data extraction were blind as to the name of the
author(s) of each study. Second, after the first review, articles were re-assigned through a second blind
randomization to a second reviewer. Finally, any disagreement between the first two reviews was
solved by a senior researcher.
Results. One-hundred fifty-one economic evaluations eventually met the inclusion criteria. Over time,
we observed an increasing transparency of methods and a greater generalizability of results, along
with a wider and more representative sample in trials and a larger adoption of transition-Markov
models. On the other hand, often context-specific economic evaluations are carried out and not enough
effort is done to assure the transferability of their results to other contexts. In recent studies, Cost-
Effectiveness Analyses and the use of the Incremental Cost-Effectiveness Ratio were preferred.
Conclusion. Despite a quite positive temporal trend, generalizability of results still appears as an
unsolved question, even if some indication of improvement within Italian studies has been observe
Antihistamines improve cardiovascular manifestations and other symptoms of long-COVID attributed to mast cell activation
No full textIntroduction: Long-COVID is a broadly defined condition and there are no effective therapies. Cardiovascular manifestations of long-COVID include high heart rate, postural tachycardia, and palpitations. Previous studies have suggested that mast cell activation (MCA) may play a role in the pathophysiology of long-COVID, including in the mechanisms of its cardiovascular manifestations. The present study aimed to evaluate the effectiveness of a treatment with blockers of histamine receptors in patients with long-COVID who did not respond to other therapies.
Methods: In all, 14 patients (F/M = 9/5; 49.5 ± 11.5 years) and 13 controls (F/M = 8/5; 47.3 ± 8.0 years) with long-COVID symptoms attributed to MCA were evaluated. Patients were treated with fexofenadine (180 mg/day) and famotidine (40 mg/day). Fatigue, brain fog, abdominal disorders, and increased heart rate were evaluated in treated and untreated patients at baseline and 20 days later. Results: Long-COVID symptoms disappeared completely in 29% of treated patients. There was a significant improvement in each of the considered symptoms (improved or disappeared) in all treated patients, and the improvement grade was significantly greater in treated patients compared to controls. No significant differences in the outcomes were observed in the controls. Conclusions: Our data confirm that histamine receptors blockade may be an effective target to successfully treat long-COVID. Our finding supports the underlying role of MCA in the pathophysiology of long-COVID
Investigating the Generalizability of Economic Evaluations Conducted in Italy: A Critical Review
No full textObjectives To assess the methodological quality of Italian health economic evaluations and their generalizability or transferability to different settings. Methods A literature search was performed on the PubMed search engine to identify trial-based, nonexperimental prospective studies or model-based full economic evaluations carried out in Italy from 1995 to 2013. The studies were randomly assigned to four reviewers who applied a detailed checklist to assess the generalizability and quality of reporting. The review process followed a three-step blinded procedure. The reviewers who carried out the data extraction were blind as to the name of the author(s) of each study. Second, after the first review, articles were reassigned through a second blind randomization to a second reviewer. Finally, any disagreement between the first two reviewers was solved by a senior researcher. Results One hundred fifty-one economic evaluations eventually met the inclusion criteria. Over time, we observed an increasing transparency in methods and a greater generalizability of results, along with a wider and more representative sample in trials and a larger adoption of transition-Markov models. However, often context-specific economic evaluations are carried out and not enough effort is made to ensure the transferability of their results to other contexts. In recent studies, cost-effectiveness analyses and the use of incremental cost-effectiveness ratio were preferred. Conclusions Despite a quite positive temporal trend, generalizability of results still appears as an unsolved question, even if some indication of improvement within Italian studies has been observed
Performance Assessment of R-454C, R-449A, and R-744 in Food Retail Refrigeration Systems
No full textReduced energy use and increased energy efficiency are essential for decarbonization and sustainable development. The food cold chain is a crucial infrastructure with high energy consumption and rising demand. A careful selection of technology used in food retail systems could result in long-term energy savings, functionality, ease of maintenance, and high energy efficiency. In this work, a comparison between the energy performance of three low-GWP refrigerants, namely, R-454C, R-449A, and R-744, is carried out with reference to an existing refrigerating system that serves a real supermarket. Energy usage and seasonal efficiency have been examined for three locations in Europe, representing mild and hot ambient temperatures. Results show that systems based on R-454C and R-449A perform significantly better than R-744 architectures, improving sCOP of up to +12% and +17%, respectively, with a simpler equipment design. This suggests that careful assessment is required to select the most appropriate refrigerant for each store size and climatic condition
The low-mass YSO
No full textContext. To investigate the earliest phases of star formation and study how newly-born stars interact with the surrounding medium, we performed a line and continuum survey at NIR and mm-wavelengths of a sample of relatively isolated Bok globules.
Aims. We present a follow-up observational program of a star-forming site
in the globule CB23
Hemodynamic effects of creatine phosphate in patients with congestive heart failure: A double‐blind comparison trial versus placebo
No full textA multi-molecular line study of the star-forming globule CB88-230
No full textContext. This paper relates to low-mass star formation in globules, and the interaction of newly-formed stars with their environment. We follow up on the results of our earlier observations of this globule.
Aims. Our aim is to study the gas- and dust environment of the young stellar object (YSO) in globule CB88 230, the large-scale molecular outflow triggered by the jet driven by the YSO, and their interaction.
Methods. We carried out submillimetre continuum and multi-line molecular observations with several single-dish facilities, mapping the core of the globule and the large-scale outflow associated with the YSO.
Results. Dust continuum and molecular line maps (of 12CO, C18O, CS, CH3OH) show a flattened (axes ratio 1.5−1.7), asymmetric core with a full width at half maximum (FWHM)-diameter of 0.16−0.21 pc. Line profiles of 12CO, 13CO(2–1, 3–2), and CS(2–1) show self-absorption near the YSO; the absorption dip is at a slightly (~0.3 km s−1) redder velocity than that of the quiescent gas, possibly indicating infall of cooler envelope gas. The mass of the core, determined from C18O(1–0) observations, is about 8 M⊙, while the virial mass is in the range 5−8M⊙, depending on the assumed density distribution. We detect a slight velocity gradient (~0.98 km s−1 pc−1), though rotational energy is negligible with respect to gravitational and turbulent energy of the core. A fit to the spectral energy distribution of the core gives a dust temperature Td ≈ 18 K and a gas mass of ca. 2 M⊙ (assuming a gas-to-dust ratio of 100). More careful modelling of the sub-mm emission (not dominated by the relatively hot central regions) yields M ≈ 8M⊙. From the molecular line observations we derive gas temperatures of 10−20 K. A Bayesian analysis of the emission of selected molecules observed towards the YSO, yields Tkin ≈ 21.4 K (68% credibility interval 14.5−35.5 K) and volume density n(H2) ≈ 4.6 × 105 cm−3 (8.3 × 104−9.1 × 105 cm−3). We have mapped the well-collimated large-scale outflow in 12CO(3–2). The outflow has a dynamical age of a few 104 yr, and contains little mass (a few 10−2 M⊙). A misalignment between the axis of this large-scale outflow and that of the hot jet close to the YSO indicates that the outflow direction may be changing with time
