163 research outputs found
Optimization of the wavesax device: numerical modelling and ocean wave basin tests
The Wavesax device has been conceived to be installed in ports and harbours, in
the Mediterranean sea. Therefore, two aspects are quite important: flexibility of the device to
fit in different structural configurations and replication in a large number of units.
Preliminary numerical modelling of the fixed component of the device has been performed using
Computational Fluid Dynamics analysis (RANS-CFD model) and considering four regular wave
conditions typical of the Mediterranean sea.
Main issues to be considered in the first stage scale modelling analysis are the effective
functionality of the device conception (scale 1:20), the optimization of the design and position of
the device in terms of generated velocity gradients in the working section where the turbine blades
are installed. The main parameters to be investigated, both with numerical modelling and ocean wave
basin tests, are the pressure field in different sections of the device, water levels for
different wave conditions and device sinking.
Following the scale model test, the numerical model was calibrated and validated. The
paper presents the results of the numerical simulations related to different configurations of
the device, under typical Mediterranean wave climates
How to manage and minimize food waste in the hotel industry? An exploratory research
Purpose – The hospitality industry is responsible for significant amounts of waste, more than one-third
of which is food waste. Through the comparison between an Italian and a Romanian hotel, this paper
aims to provide a better understanding of food waste management trends in the hotel industry as well
as to highlight hotel kitchens and hotel food services weaknesses and opportunities to minimize food
waste.
Design/methodology/approach – In-depth interviews, personal communication and observations were
conducted to investigate food service planning, food procurement and food waste management, as well
as to better comprehend current individuals’ understanding and attitudes, infrastructures, legislative
culture and opportunities either from the managerial and the employees’ perspective. Data were
analyzed according to a content analysis approach.
Findings – Three critical hot spots emerged from the analysis: prediction and check of guests’
attendance, communication and transparency with local suppliers and among departments within the
unit and purchasing frequency and perishable food provisioning. The accurate forecasting of the number
of guests and their nationality is fundamental in avoiding food waste at food service, as well as
implementing transparency and communication with local suppliers.
Originality/value – Although academia and authorities have recognized the crucial importance of food
waste management, food waste research in the hotel industry remains under-researched. The present
exploratory research contributes to the scarce empirical studies about hotels’ food waste, giving
theoretical and managerial recommendations for supporting further studies, highlighting the need for
formal deals between hotels and local suppliers (food procurement), as well as the importance of foodnetworks
that holds together companies, retailers and charities (food donation)
Enhancing the Sustainability of the Aviation Industry: Airlines’ Commitment to “Green” Practices
The aviation industry represents an important polluter, being responsible for increasing
environmental impacts on global scale. Aiming to approach the adoption of suitable policies
in the aviation industry towards the achievement of the national and international
sustainability goals, the present research tackles airlines’ commitment to aviation-related
environmental issues, as well as their willingness to adopt sustainable aviation fuel (i.e., bio
jet fuel) and sustainable development strategies, focusing on those companies operating
flights in the Karol Wojtyła Airport (Bari, Italy). The paper adopts the χ2 test and the logistic
regression to investigate three different hypotheses related to airlines’ headquarters, carriers’
typology (i.e., low-cost or not, flag carriers or not) and years of service. Results outline that
traditional airlines, either flag carriers or not, as well as South and North American
companies, are more likely to be aware of aviation environmental consequences, publishing
environmental reports and offering to passengers the chance to participate to climate change
reduction (e.g., through online carbon offset programs or more expensive ticket to produce
bio jet fuels). In addition, airlines transiting in Karol Wojtyła Airport show a small
willingness to share information through environmental reports and are scarcely intentioned
to make use of bio jet fuels, confirming that low-cost companies are still less attentive
towards aviation environmental issues. The present research contributes to the empirical
studies on sustainable aviation and carriers’ commitment to environmental strategies,
highlighting the need to enhance carbon offsets programs and digital technologies as the
online compensation of CO2 emissions
SPH modeling of water-related natural hazards
This paper collects some recent smoothed particle hydrodynamic (SPH) applications in the field of natural hazards connected to rapidly varied flows of both water and dense granular mixtures including sediment erosion and bed load transport. The paper gathers together and outlines the basic aspects of some relevant works dealing with flooding on complex topography, sediment scouring, fast landslide dynamics, and induced surge wave. Additionally, the preliminary results of a new study regarding the post-failure dynamics of rainfall-induced shallow landslide are presented. The paper also shows the latest advances in the use of high performance computing (HPC) techniques to accelerate computational fluid dynamic (CFD) codes through the efficient use of current computational resources. This aspect is extremely important when simulating complex three-dimensional problems that require a high computational cost and are generally involved in the modeling of water-related natural hazards of practical interest. The paper provides an overview of some widespread SPH free open source software (FOSS) codes applied to multiphase problems of theoretical and practical interest in the field of hydraulic engineering. The paper aims to provide insight into the SPH modeling of some relevant physical aspects involved in water-related natural hazards (e.g., sediment erosion and non-Newtonian rheology). The future perspectives of SPH in this application field are finally pointed out
CONTROL BASED ON NUMERICAL METHODS AND RECURSIVE BAYESIAN ESTIMATION IN A CONTINUOUS ALCOHOLIC FERMENTATION PROCESS
Biotechnological processes represent a challenge in the control field, due to their high nonlinearity. In particular, continuous alcoholic fermentation from Zymomonas mobilis (Z.m) presents a significant challenge. This bioprocess has high ethanol performance, but it exhibits an oscillatory behavior in process variables due to the influence of inhibition dynamics (rate of ethanol concentration) over biomass, substrate, and product concentrations. In this work a new solution for control of biotechnological variables in the fermentation process is proposed, based on numerical methods and linear algebra. In addition, an improvement to a previously reported state estimator, based on particle filtering techniques, is used in the control loop. The feasibility estimator and its performance are demonstrated in the proposed control loop. This methodology makes it possible to develop a controller design through the use of dynamic analysis with a tested biomass estimator in Z.m and without the use of complex calculations
Altered inflammasome machinery as a key player in the perpetuation of Rett syndrome oxinflammation
Rett syndrome (RTT) is a progressive neurodevelopmental disorder mainly caused by mutations in the X-linked MECP2 gene. RTT patients show multisystem disturbances associated with an oxinflammatory status. Inflammasomes are multi-protein complexes, responsible for host immune responses against pathogen infections and redox-related cellular stress. Assembly of NLRP3/ASC inflammasome triggers pro-caspase-1 activation, thus, resulting in IL-1β and IL-18 maturation. However, an aberrant activation of inflammasome system has been implicated in several human diseases. Our aim was to investigate the possible role of inflammasome in the chronic subclinical inflammatory condition typical of RTT, by analyzing this complex in basal and lipopolysaccharide (LPS)+ATP-stimulated primary fibroblasts, as well as in serum from RTT patients and healthy volunteers. RTT cells showed increased levels of nuclear p65 and ASC proteins, pro-IL-1β mRNA, and NLRP3/ASC interaction in basal condition, without any further response upon the LPS + ATP stimuli. Moreover, augmented levels of circulating ASC and IL-18 proteins were found in serum of RTT patients, which are likely able to amplify the inflammatory response. Taken together, our findings suggest that RTT patients exhibited a challenged inflammasome machinery at cellular and systemic level, which may contribute to the subclinical inflammatory state feedback observed in this pathology
Mense e personale addetto alle cucine: valutazione dei rischi occupazionali
The aim of the study is to evaluate the occupational risks among food service workers and cooks. During the occupational risks assessment the following risk factors must be evaluated: musculoskeletal disorders, chemical risk (cleaning kitchen work surface, dishes, utensils ecc.) biological risk (contact with foods or biological agents) cancerogenic risk (by baking smoke inhalation), and psycho-social stress. In this study the preventive measures and protective equipment to prevent health hazards for these workers have been evaluated (i.e. aspiration hood, adapted ventilation, chosen of less harmful methods of baking, ecc.). In particular the performance of rigid behavioural norms and hygienic procedures is very important for cooks and food service workers to reduce the risk of occupational infections
PULEX: Influence of environment radiation background on biochemistry and biology of cultured cells and on their response to genotoxic agents
Some years ago we performed two experiments aimed at studying the influence of the background radiation on living matter by exploiting the low radiation background environment in the underground Gran Sasso Laboratory of the INFN. Their results were consistent with the hypothesis that the “normal” background radiation determines an adaptive response, although they cannot be considered conclusive. PULEX-3 (the third experiment of the series) is aimed at comparing the effects of different background radiation environments on metabolism of cultured mammalian cells, with substantial improvements with respect to the preceding ones. The experiment was designed to minimize variabilities, by maintaining two cultures of Chinese hamster V79 cells in exponential growth for up to ten months
in the underground Gran Sasso Laboratory (LNGS), while two other cultures were maintained in parallel in a biological laboratory installed at the LNGS outside the tunnel. Exposure due to γ-rays was reduced by a factor of about 10 in the underground laboratory while the Rn concentration was small in both cases. After ten months the cells grown in the underground laboratory, compared to those grown in the external one, exhibited: i) a significantly lower capacity to scavenge reactive oxygen species (ROS), and ii) an increased sensitivity to the mutagenic effect of rays. Since the probability that this finding is due to casual induction of radiosensitive mutants is extremely low, it corroborates the hypothesis that cells grown in a “normal” background radiation environment exhibit an adaptive response when challenged with genotoxic agents, which is lost after many generations in a low background radiation environment
Endothelial cells from umbilical cord of women affected by gestational diabetes: A suitable in vitro model to study mechanisms of early vascular senescence in diabetes
Human umbilical cord endothelial cells (HUVECs) obtained from women affected by gestational diabetes (GD-HUVECs) display durable pro-atherogenic modifications and might be considered a valid in vitro model for studying chronic hyperglycemia effects on early endothelial senescence. Here, we demonstrated that GD- compared to C-HUVECs (controls) exhibited oxidative stress, altered both mitochondrial membrane potential and antioxidant response, significant increase of senescent cells characterized by a reduced NAD-dependent deacetylase sirtuin-1 (SIRT1) activity together with an increase in cyclin-dependent kinase inhibitor-2A (P16), cyclin-dependent kinase inhibitor-1 (P21), and tumor protein p53 (P53) acetylation. This was associated with the p300 activation, and its silencing significantly reduced the GD-HUVECs increased protein levels of P300 and Ac-P53 thus indicating a persistent endothelial senescence via SIRT1/P300/P53/P21 pathway. Overall, our data suggest that GD-HUVECs can represent an “endothelial hyperglycemic memory” model to investigate in vitro the early endothelium senescence in cells chronically exposed to hyperglycemia in vivo
- …