Bio-hythane production from food waste by dark fermentation coupled with anaerobic digestion process: A long-term pilot scale experience

In this paper are presented the results of the investigation on optimal process operational conditions of thermophilic dark fermentation and anaerobic digestion of food waste, testing a long term run, applying an organic loading rate of 16.3 kgTVS/m3d in the first phase and 4.8 kgTVS/m3d in the second phase. The hydraulic retention times were maintained at 3.3 days and 12.6 days, respectively, for the first and second phase. Recirculation of anaerobic digested sludge, after a mild solid separation, was applied to the dark fermentation reactor in order to control the pH in the optimal hydrogen production range of 5-6. It was confirmed the possibility to obtain a stable hydrogen production, without using external chemicals for pH control, in a long term test, with a specific hydrogen production of 66.7 l per kg of total volatile solid (TVS) fed and a specific biogas production in the second phase of 0.72 m3 per kgTVS fed; the produced biogas presented a typical composition with a stable presence of hydrogen and methane in the biogas mixture around 6 and 58%, respectively, carbon dioxide being the rest

OMA analysis of a launcher under operational conditions with time-varying properties

The objective of the paper is the investigation of the capability of Operational Modal Analysis approaches to deal with time-varying system in the low-frequency domain. Specifically, the problem of the identification of the dynamic properties of a launch-vehicle, working under actual operative conditions, is studied. Two OMA methods are considered: the Frequency Domain Decomposition and the Hilbert Transform Method. It is demonstrated that both OMA approaches allow the time-tracking of modal parameters, namely, natural frequencies, damping ratios and mode shapes, from the response accelerations only recorded during actual flight tests of a launcher characterized by a large mass variation due to fuel burning typical of the first phase of the flight

Simulation of the 2009, Mw = 4 Tehran earthquake using a hybrid method of modal summation and finite difference

The Greater Tehran Area is the most important city of Iran and hosts about 20% of the country?s population. Despite the presence of major faults and the occurrence of historical earthquakes, the seismicity is relatively low at present. Thus, it is important to estimate the ground motion for preventive, reliable seismic hazard assessment. An earthquake with magnitude Mw = 4, which occurred close to Tehran, 17 October 2009, is the first local earthquake that has been recorded by the local strong ground motion network in Tehran. To simulate the ground motion caused by the earthquake a hybrid technique is used. It combines two methods: the analytical modal summation and the numerical finite difference, taking advantage of the merits of both. The modal summation is applied to simulate wave propagation from the source to the sedimentary basin and finite difference to propagate the incoming wavefield in the laterally heterogeneous part of the structural model that contains the sedimentary basin. Synthetic signals are simulated along two East?West and Southeast?Northwest profiles. Frequency, response spectra, and time domain, waveforms and peak values, parameters are computed synthetically and compared with observed records. Results show agreement between observed and simulated signals. The simulation shows local site amplification as high as 6 in the southern part of Tehran

L'elettrolisi: un'occasione per riflettere sulla Chimica, ma anche sulla storia, l'economia, l'ambiente

Pensiamo che partire da esempi tratti dal mondo che ci circonda, in cui le procedure della Chimica, sia teoriche che sperimentali, appaiano in tutto il loro intreccio con le attività umane, possa costituire un metodo efficace per fornire a vari livelli un’immagine della disciplina corretta. Ciò può aiutare ad approcciarsi ad essa senza paure e senza trionfalismi. Nell’articolo in particolare si tratteranno alcuni significativi processi di elettrolisi, evidenziando il loro sviluppo storico e le loro implicazioni dal punto di vista produttivo e del rapporto con uomo e ambiente.We believe that an effective way to provide, at various levels, a correct image of Chemistry could be based on examples from the world around us, in which the procedures of the discipline, both theoretical and experimental, appear in all their interweaving with human activities. This may help to approach it without fear and without triumphalism. In the article in particular we discuss some significant electrolysis processes, highlighting their his- torical development and their implications from the point of view of production and the rela- tionship with man and environment

Evolutionary appearance of von Economo's neurons in the mammalian cerebral cortex.

von Economo’s neurons (VENs) are large, spindle-shaped projection neurons in layer V of the frontoinsular (FI) cortex, and the anterior cingulate cortex. During human ontogenesis, the VENs can first be differentiated at late stages of gestation, and increase in number during the first eight postnatal months. VENs have been identified in humans, chimpanzee, bonobos, gorillas, orangutan and, more recently, in the macaque. Their distribution in great apes seems to correlate with human-like social cognitive abilities and self-awareness. VENs are also found in whales, in a number of different cetaceans, and in the elephant. This phylogenetic distribution may suggest a correlation among the VENs, brain size and the “social brain.” VENs may be involved in the pathogenesis of specific neurological and psychiatric diseases, such as autism, callosal agenesis and schizophrenia. VENs are selectively affected in a behavioral variant of frontotemporal dementia in which empathy, social awareness and self-control are seriously compromised, thus associating VENs with the social brain. However, the presence of VENs has also been related to special functions such as mirror self-recognition. Areas containing VENs have been related to motor awareness or sense-of-knowing, discrimination between self and other, and between self and the external environment. Along this line, VENs have been related to the “global Workspace” architecture: in accordance the VENs have been correlated to emotional and interoceptive signals by providing fast connections (large axons = fast communication) between salience-related insular and cingulate and other widely separated brain areas. Nevertheless, the lack of a characterization of their physiology and anatomical connectivity allowed only to infer their functional role based on their location and on the functional magnetic resonance imaging data. The recent finding of VENs in the anterior insula of the macaque opens the way to new insights and experimental investigations

Experimental Validation of Neural-Network-Based Nonlinear Reduced-Order Model for Vertical Sloshing

In this paper, a nonlinear reduced order model based on neural networks is introduced in order to model vertical sloshing for use in fluid-structure interaction simulations. A box partially filled with water, representative of a wing tank, is first tested to identify a neural network model and then attached to a cantilever beam to test the effectiveness of the neural network in predicting the sloshing forces when coupled with the structure. The experimental set-up is equipped with accelerometers and load cells at the interface between the tank and an electrodynamic shaker, which provides vertical acceleration to the tank. Accelerations and interface forces measured during the experimental tests are employed to identify a recurrent network able to return the vertical sloshing forces when the tank is set on vertical motion. The identified model is then experimentally tested and assessed by its integration on the tip of a cantilever beam. The free response of the experimental setup are compared with those obtained by simulating an equivalent virtual model in which the identified reduced-order model is integrated to account for the effects of vertical sloshing

A Contribution to New Material Standards for Ductile Irons and Austempered Ductile Irons

Some results of materials characterization activities, dedicated to classical and notch mechanics fatigue and elastoplastic properties, have already been published for some Ferritic–Pearlitic Ductile Iron, including the patented heat treated Isothermed (IDI) and Austempered Ductile Iron (ADI) grades. Others have not yet been published. The possible use of all of these results in new standards is discussed in this paper. It is proposed that new standards should provide a criterion that is able to measure the process quality that represents more accurately the actual market needs and manufacturing capabilities. Classification of grades, considered by existing standards, is based on minimum properties for strength and ductility parameters that are separately evaluated. A different approach that is based on a quality index, which considers strength and ductility all in one, is proposed. However, this new proposed approach may not be sufficient to provide a satisfactory classification for the ADIs. This is because their fracture mechanical behavior and machinability can be correlated with their austenite stability. It could also be insufficient for the classification of the recent High Silicon Solid Solution Strengthened Ductile Irons that exhibit a decreasing ultimate tensile strength/proof stress ratio with increasing Si. For construction steels, fracture mechanics properties are sometimes believed to be related to the Charpy impact energy. This paper introduces an innovative practical and inexpensive data analysis, performed on the tensile test curve, which appears to be a potential estimator of fracture mechanical properties, at least for ADIs, where said properties could be correlated with the austenite stability