Smart approaches to food waste final disposal

Food waste, among the organic wastes, is one of the most promising substrates to be used as a renewable resource. Wide availability of food waste and the high greenhouse gas impacts derived from its inappropriate disposal, boost research through food waste valorization. Several innovative technologies are applied nowadays, mainly focused on bioenergy and bioresource recovery, within a circular economy approach. Nevertheless, food waste treatment should be evaluated in terms of sustainability and considering the availability of an optimized separate collection and a suitable treatment facility. Anaerobic codigestion of waste-activated sludge with food waste is a way to fully utilize available anaerobic digestion plants, increasing biogas production, energy, and nutrient recovery and reducing greenhouse gas (GHG) emissions. Codigestion implementation in Europe is explored and discussed in this paper, taking into account different food waste collection approaches in relation to anaerobic digestion treatment and confirming the sustainability of the anaerobic process based on case studies. Household food waste disposal implementation is also analyzed, and the results show that such a waste management system is able to reduce GHG emissions due to transport reduction and increase wastewater treatment performance

First- and second-generation valorisation of wastes and residues occurring in the food supply chain

Despite the high potential to increase sustainability of food systems, wastes and by-products occurring in the food supply chain are currently only partially valorised at different value-added levels. First-generation valorisation strategies that aim at utilisation of complete material streams for production of animal feed, energy, compost and/or specific consumer applications are already widely implemented and experience further dissemination and/or development (e.g. biohydrogen/biohythane production) – either in the form of single processes or as part of cascade utilisations. Second-generation valorisation strategies comprise various forms of fractionised utilisation of material streams. They rely on integration of adapted recovery and conversion procedures for specific components in order to obtain sequentially different classes of products, e.g. fine chemicals, commodity products and biofuels. Such advanced strategies are particularly suitable for wastes and by-products occurring during industrial food processing. Valorisation of food by-products for functional food is an emerging trend

Semi-continuous Chlorella vulgaris Cultivation Using Anaerobic Digestate Liquid Fraction Pre-treated by Ultrasonic Cavitation to Improve Carbon Dioxide Solubilization

Nutrients-enriched effluents such as digestate can represent a suitable and economically appealing substrate for microalgae growth since they combine the effluent treatment with biomass production. Then, microalgae biomass can be exploited to produce several bio-based compounds. However, the use of digestate for microalgae cultivation can be challenging due to its high levels of ammonia nitrogen and its low C/N ratio. For this reason, an ultrasonic cavitation (UC) process combined with carbon dioxide (CO2) insufflation was tested on digestate, in order to obtain a faster solubilization of the CO2 in the medium and thus an increase in the C/N ratio. The test was carried out growing Chlorella vulgaris on both digestate (mixotrophic condition) and BG-11 medium (autotrophic condition) in 1 L photobioreactors. For the first 14 days of the experiment the reactors were maintained in batch conditions to acclimatize microalgae. Then, they were switched to semi-continuous for 32 days. The reactors were fed three times a week, with an HRT (Hydraulic Retention Time) of 10.5 d as weekly average. Regarding the test on digestate, both UC pre-treated and untreated conditions reached the highest biomass production at the end of the batch (4.8 and 4.1 g L-1 respectively) and a complete ammonium (NH4+) removal after 9 days. The switch to semi-continuous caused an increase in NH4+ concentration and a consistent decrease in biomass concentration. Biomass production reached the steady-state, with a concentration of 1.9 and 1.2 g L-1 for the UC pre-treated and untreated digestate, respectively (+55.6 % biomass production obtained with UC pre-treated digestate). Moreover, an NH4+ removal of 93.5 % and 92.3 % was reached for UC pre-treated and untreated conditions, respectively

Anaerobic co-digestion effluent as substrate for chlorella vulgaris and scenedesmus obliquus cultivation

Anaerobic digestate supernatant can be used as a nutrient source for microalgae cultivation, thus integrating phytoremediation processes with high value products storage in microalgae biomass. Microalgae are able to use nitrogen and phosphorous from digestate, but high nutrient concentration can cause growth inhibition. In this study, two microalgae strains (C. vulgaris and S. obliquus) were cultivated on the anaerobic co-digestion supernatant (obtained from the organic fraction of municipal solid waste (OFMSW) and waste activated sludge (WAS)) in a preliminary Petri plate screening at different dilutions (1:10 and 1:5) using a synthetic medium (ISO) and tap water (TW). Direct Nile red screening was applied on colonies to preliminarily identify hydrophobic compound storage and then a batch test was performed (without air insufflation). Results show that C. vulgaris was able to grow on digestate supernatant 1:5 diluted, while Nile red screening allowed the preliminary detection of hydrophobic compound storage in colonies. The analysis carried out at the end of the test on ammonia, phosphate, nitrate and sulphate showed a removal percentage of 47.5 ± 0.8%, 65.0 ± 6.0%, 95.0 ± 3.0% and 99.5 ± 0.1%, respectively

Multivariate statistical process monitoring using classical multidimensional scaling

A new Multivariate Statistical Process Monitoring (MSPM) system, which comprises of three main frameworks, is proposed where the system utilizes Classical Multidimensional Scaling (CMDS) as the main multivariate data compression technique instead of using the linearbased Principal Component Analysis (PCA). The conventional method which usually applies variance-covariance or correlation measure in developing the multivariate scores is found to be inappropriately used especially in modelling nonlinear processes, where a high number of principal components will be typically required. Alternatively, the proposed method utilizes the inter-dissimilarity scales in describing the relationships among the monitored variables instead of variance-covariance measure for the multivariate scores development. However, the scores are plotted in terms of variable structure, thus providing different formulation of statistics for monitoring. Nonetheless, the proposed statistics still correspond to the conceptual objective of Hotelling’s T2 and Squared Prediction Errors (SPE). The first framework corresponds to the original CMDS framework, whereas the second utilizes Procrustes Analysis (PA) functions which is analogous to the concept of loading factors in PCA for score projection. Lastly, the final framework employs dynamic mechanism of PA functions as an alternative for enhancing the procedures of the second approach. A simulated system of Continuous Stirred Tank Reactor with Recycle (CSTRwR) has been chosen for the demonstration and the fault detection results were comparatively analyzed to the outcomes of PCA on the grounds of false alarm rates, total number of detected cases and also total number of fastest detection cases. The last two performance factors are obtained through fault detection time. The overall outcomes show that the three CMDS-based systems give almost comparable performances to the linear PCA based monitoring systemwhen dealing the abrupt fault events, whereas the new systems have demonstrated significant improvement over the conventional method in detecting incipient fault cases. More importantly, this monitoring accomplishment can be efficiently executed based on lower compressed dimensional space compared to the PCA technique, thus providing much simpler solution. All of these evidences verified that the proposed approaches are successfully developed conceptually as well as practically for monitoring while complying fundamentally with the principles and technical steps of the conventional MSPM system.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Bite force evaluation in children following dental treatment

A number of research studies have highlighted the fact that poor dental health impacts on quality of life as a whole due to a number of different elements. Dental caries is usually associated with negative consequences, such as discomfort and pain, which are known to affect growth and weight gain through effects on function, in addition to wellbeing and quality of life (George et al., 1999; Wendy and Sharleen, 1999). It has been suggested that a significant number of children may not be able to verbally complain of pain. This inability may be caused by their immaturity, level of cognition and language development. Children usually show difficulty in eating and loss of function which should be considered an indicator of oral problems (Anderson et al, 2004). Therefore functional impairment is a negative sequel of caries in children. This can be measured by different means and one of those is the evaluation of bite force which is known to be influential on mastication and chewing processes. Bite force can be defined as ―the capacity of the mandibular elevation muscles to perform a maximum force of lower teeth against the upper teeth, under favourable conditions (Calderon et al, 2006). The evaluations of bite force have been proven to be constructive and thus widely utilised in dentistry (Koc et al., 2010), with the measurement of such conducted with the aim of determining muscular activity and jaw movements during the chewing process (Bakke,1992), with measurements also valuable in terms of masticatory efficiency (Toro et al., 2006; Julien et al., 1996). When reviewing the literature on bite force and correlated factors, it becomes apparent that there is a lack in studies concerned with the effects of dental decay on bite force in child population specifically. This is a clinical exploratory study that comprised 32 children (26 with completed measurements) with a mean age of 6.45 years. 43.75 % were boys and 56.25 % were girls. The study sample was taken from children attending the Leeds Dental Hospital/Paediatric Dentistry Department for treatment. The Maximum Voluntary Comfortable bite force was determined for each participant immediately before treatment and 3-5 weeks following completion of the required dental treatment. A single tooth bite force device was used that has been previously verified for intra-oral use in children (Mountain, 2008). The difference in bite force magnitude before and after dental treatment was analysed statistically. In addition, the correlations of key variables including, age, height, weight, BMI, gender and caries severity or dental status with maximum bite force were statistically analysed. The mean maximum bite force for the total sample (n= 32) prior to treatment was found to be 169.32 N (SD= 66.20). The mean bite force in the male subgroup was 174.49 N (SD= 64.69) while for the females the mean bite force was equal to 165.29 N (SD= 68.93). Following comprehensive dental treatment the recorded mean maximum bite force for the children (n= 26) who attended the post treatment review appointment was 180.60 N (SD= 65.85). Paired sample t test revealed a statistically significant increase in mean maximum bite force (p < 0.01) following comprehensive dental treatment that included both restorations and extractions. Correlation coefficients were determined for a number of key variables and maximum voluntary bite force in the pre-treatment stage. Child‘s gender failed to show significant correlation with the bite force. In contrast, child‘s age, body build expressed by height and weight showed a significant positive correlation with bite force (p < 0.01). In addition, poor dental status prior to treatment, expressed by the number of decayed, missing and filled teeth and surfaces, exhibited a statistically significant negative correlation with the bite force (p < 0.05). Presence of an abscess and dental pain showed similar negative impact on bite force. The present study‘s findings can be important in the field of paediatric dentistry. In addition to the previously proved positive effects of treating dental caries in children, this study adds that bite force and subsequently chewing function can be improved by comprehensive dental treatment of decayed teeth. Additionally, this study showed that bite force in children is negatively impacted by a number of essential factors including, severity of dental caries as well as presence of clinical symptoms (i.e. pain and dental abscess). Therefore, the findings can serve as an additional supportive evidence of importance of dental treatment for children as it helps improving the maximum bite force a child can exert.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Coherence and Consciousness: Study of Fronto-Parietal Gamma Synchrony in Patients with Disorders of Consciousness

Evaluation of consciousness needs to be supported by the evidence of brain activation during external stimulation in patients with unresponsive wakefulness syndrome (UWS). Assessment of patients should include techniques that do not depend on overt motor responses and allow an objective investigation of the spontaneous patterns of brain activity. In particular, electroencephalography (EEG) coherence allows to easily measure functional relationships between pairs of neocortical regions and seems to be closely correlated with cognitive or behavioral measures. Here, we show the contribution of higher order associative cortices of patients with disorder of consciousness (N\ua0=\ua026) in response to simple sensory stimuli, such as visual, auditory and noxious stimulation. In all stimulus modalities an increase of short-range parietal and long-range fronto-parietal coherences in gamma frequencies were seen in the controls and minimally conscious patients. By contrast, UWS patients showed no significant modifications in the EEG patterns after stimulation. Our results suggest that UWS patients can not activate associative cortical networks, suggesting a lack of information integration. In fact, fronto-parietal circuits result to be connectively disrupted, conversely to patients that exhibit some form of consciousness. In the light of this, EEG coherence can be considered a powerful tool to quantify the involvement of cognitive processing giving information about the integrity of fronto-parietal network. This measure can represent a new neurophysiological marker of unconsciousness and help in determining an accurate diagnosis and rehabilitative intervention in each patient

Self-consistent simulation of plasma scenarios for ITER using a combination of 1.5D transport codes and free-boundary equilibrium codes

Self-consistent transport simulation of ITER scenarios is a very important tool for the exploration of the operational space and for scenario optimisation. It also provides an assessment of the compatibility of developed scenarios (which include fast transient events) with machine constraints, in particular with the poloidal field (PF) coil system, heating and current drive (H&CD), fuelling and particle and energy exhaust systems. This paper discusses results of predictive modelling of all reference ITER scenarios and variants using two suite of linked transport and equilibrium codes. The first suite consisting of the 1.5D core/2D SOL code JINTRAC [1] and the free boundary equilibrium evolution code CREATE-NL [2,3], was mainly used to simulate the inductive D-T reference Scenario-2 with fusion gain Q=10 and its variants in H, D and He (including ITER scenarios with reduced current and toroidal field). The second suite of codes was used mainly for the modelling of hybrid and steady state ITER scenarios. It combines the 1.5D core transport code CRONOS [4] and the free boundary equilibrium evolution code DINA-CH [5].Comment: 23 pages, 18 figure

Analysis of exchange terms in a projected ERPA Theory applied to the quasi-elastic (e,e') reaction

A systematic study of the influence of exchange terms in the longitudinal and transverse nuclear response to quasi-elastic (e,e') reactions is presented. The study is performed within the framework of the extended random phase approximation (ERPA), which in conjuction with a projection method permits a separation of various contributions tied to different physical processes. The calculations are performed in nuclear matter up to second order in the residual interaction for which we take a (pi+rho)-model with the addition of the Landau-Migdal g'-parameter. Exchange terms are found to be important only for the RPA-type contributions around the quasielastic peak.Comment: 29 pages, 6 figs (3 in postscript, 3 faxed on request), epsf.st