Domestic heating: Can hemp-hurd derived pellet be an alternative?

Among the renewable sources, residual woody biomass from agricultural crops is becoming of great interest due to its lower environmental impact and one of the most growing agricultural sector, of the last decade, is the hemp industry which generates several kind of byproducts. In this paper, a blend of 50% of hemp-hurd and 50% of fir sawdust was pulverized and pelletized. The pellets were burned into a domestic pellet stove (9 kWth maximum nominal thermal power output) at different biomass flowrates. To compare results with a commercial-grade pellet, the tests were repeated by fueling the same stove with A2-grade pellets. Results shown that the pellet mixture 50/50 of fir sawdust and hemp-hurd is suitable for the commercial pellet stove used and that the slightly higher amount of ashes (2.7%), compared to pellet A2 (<1.2%), can be handled by the self-cleaning fire chamber. Comparable results were also obtained in regards with the stove global efficiency which ranged from 90.8-92.3% for the hemp pellets and 91-94% for the A2. A significant difference was noted in the biomass flowrate where, during the tests with hemp-hurd pellets a lower value was obtained (-20%) compared to A2. This resulted into lower power input in the stove and lower performances at the same nominal power output

Density Functional Theory: Methods and Problems

The application of density functional theory to nuclear structure is discussed, highlighting the current status of the effective action approach using effective field theory, and outlining future challenges.Comment: 10 pages, 14 figures, invited talk at INT workshop on Nuclear Forces and the Quantum Many-Body Problem, Seattle, October 200

Inorganic phosphate is a trigger factor for Microbispora sp. ATCC-PTA-5024 growth and NAI-107 production

BACKGROUND: NAI-107, produced by the actinomycete Microbispora sp. ATCC-PTA-5024, is a promising lantibiotic active against Gram-positive bacteria and currently in late preclinical-phase. Lantibiotics (lanthionine-containing antibiotics) are ribosomally synthesized and post-translationally modified peptides (RiPPs), encoded by structural genes as precursor peptides. The biosynthesis of biologically active compounds is developmentally controlled and it depends upon a variety of environmental stimuli and conditions. Inorganic phosphate (Pi) usually negatively regulates biologically-active molecule production in Actinomycetes, while it has been reported to have a positive control on lantibiotic production in Firmicutes strains. So far, no information is available concerning the Pi effect on lantibiotic biosynthesis in Actinomycetes. RESULTS: After having developed a suitable defined medium, Pi-limiting conditions were established and confirmed by quantitative analysis of polyphosphate accumulation and of expression of selected Pho regulon genes, involved in the Pi-limitation stress response. Then, the effect of Pi on Microbispora growth and NAI-107 biosynthesis was investigated in a defined medium containing increasing Pi amounts. Altogether, our analyses revealed that phosphate is necessary for growth and positively influences both growth and NAI-107 production up to a concentration of 5 mM. Higher Pi concentrations were not found to further stimulate Microbispora growth and NAI-107 production. CONCLUSION: These results, on one hand, enlarge the knowledge on Microbispora physiology, and, on the other one, could be helpful to develop a robust and economically feasible production process of NAI-107 as a drug for human use. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12934-014-0133-0) contains supplementary material, which is available to authorized users

Time-Dependent Density-Functional Theory for Trapped Strongly-Interacting Fermionic Atoms

The dynamics of strongly interacting trapped dilute Fermi gases (dilute in the sense that the range of interatomic potential is small compared with inter-particle spacing) is investigated in a single-equation approach to the time-dependent density-functional theory. Our results are in good agreement with recent experimental data in the BCS-BEC crossover regime. It is also shown that the calculated corrections to the hydrodynamic approximation may be important even for systems with a rather large number of atoms.Comment: Resubmitted to PRA in response to referee's comments. Abstract is changed. Added new figure

Pan-European ground-motion prediction equations for the average horizontal component of PGA, PGV, and 5 %-damped PSA at spectral periods up to 3.0 s using the RESORCE dataset

This article presents a set of Ground-Motion Prediction Equations (GMPEs) for Europe and the Middle East, derived from the RESORCE strong motion data bank, following a standard regression approach. The parametric GMPEs are derived for the peak ground acceleration, peak ground velocity, and 5 %-damped pseudo-absolute acceleration response spectra computed over 23 periods between 0.02 and 3 s, considering the average horizontal-component ground-motions. The GMPEs are valid for distances less than 300 km, hypocentral depth up to 35 km and over the magnitude range 4–7.6. Two metrics for the source-to-station distance (i.e. Joyner-Boore and hypocentral) are considered. The selected dataset is composed by 2,126 recordings (at a period of 0.1 s) related to 365 earthquakes, that includes strong-motion data from 697 stations.The EC8 soil classification (four classes from A to D) discriminates recording sites and four classes (normal, reverse, strike-slip, and unspecified) describe the style of faulting. A subset which contains only stations with measured Vs30 and earthquakes with specified focal mechanism (1,224 records from 345 stations and 255 earthquakes) is used to test of the accuracy of the median prediction and the variability associated to the broader data set. A random effect regression scheme is applied and bootstrap analyses are performed to estimate the 95 % confidence levels for the parameters. The total standard deviation sigma is decomposed into between-events and within-event components, and the site-to-site component is evaluated as well. The results show that the largest contribution to the total sigma is coming from the within-event component. When analyzing the residual distributions, no significant trends are observed that can be ascribed to the earthquake type (mainshock-aftershock classification) or to the non-linear site effects. The proposed GMPEs have lower median values than global models at short periods and large distances, while are consistent with global models at long periods (T>1) s. Consistency is found with two regional models developed for Turkey and Italy, as the considered dataset is dominated by waveforms recorded in these regions

Bacterial community structure and removal performances in IFAS-MBRs: A pilot plant case study

The paper reports the results of an experimental campaign carried out on a University of Cape Town (UCT) integrated fixed-film activated sludge (IFAS) membrane bioreactor (MBR) pilot plant. The pilot plant was analysed in terms of chemical oxygen demand (COD) and nutrients removal, kinetic/stoichiometric parameters, membrane fouling and sludge dewaterability. Moreover, the cultivable bacterial community structure was also analysed. The pilot plant showed excellent COD removal efficiency throughout experiments, with average value higher than 98%, despite the slight variations of the influent wastewater. The achieved nitrification efficiency was close to 98% for most of the experiments, suggesting that the biofilm in the aerobic compartment might have sustained the complete nitrification of the influent ammonia, even for concentrations higher than 100\ua0mg\ua0L-1. The irreversible resistance due to superficial cake deposition was the mechanism that mostly affected the membrane fouling. Moreover, it was noticed an increase of the resistance due pore blocking likely due to the increase of the EPSBound fraction that could derive by biofilm detachment. The bacterial strains isolated from aerobic tank are wastewater bacteria known for exhibiting efficient heterotrophic nitrification\ue2\u80\u93aerobic denitrification and producing biofilm

Mechanical and thermal properties of crab chitin reinforced carboxylated SBR composites

The addition of small amounts (up to 9 wt%) of chitin microsized particles, originating from shellfish waste, to carboxylated styrene-butadiene rubber (XSBR) matrix (as received and annealed to 100°C) has been studied. In particular, this study concentrated on their mechanical (creep investigation by nanoindentation and dynamical-mechanical analysis), thermal (differential scanning calorimetry and thermogravimetry) and swelling behaviour (toluene absorption) and was completed by morphological characterisation by scanning electron microscopy and atomic force microscopy. The results show that annealing has a limited effect on materials properties, effects which are further reduced by the addition of growing amounts of crab chitin. It should be noted that the limited filler content used in the study does not substantially modify the linear creep behaviour of XSBR for sufficiently long loading times. The thermal stability of the system does also appear to be preserved even with the maximum chitin content added, while it serves sufficiently as an effective barrier against aromatic solvent absorption

What can we learn from the January 2012 Northern Italy earthquakes?

This note focuses on the ground motion recorded during the recent moderate earthquakes occurred in the central part of Northern Italy (panel 1), a region characterized by low seismicity. For this area the Italian seismic hazard map (Stucchi et al., 2011) assigns a maximum horizontal acceleration (rock site) up to 0.2 g (10% probability of exceedance in 50 yrs). In the last 4 years, the region was struck by 9 earthquakes in the magnitude range 4≤Mw≤5.0, with the three largest located in the Northern Apennines (Mw 4.9 and 5.0 Parma events, December 2008 and January 2012) and in the Po plain (Mw 4.9 Reggio Emila event of January 2012). We analyze the strongmotion data (distance < 300 km) from these events recorded by stations belonging to the INGV (RAIS, http://rais.mi.ingv.it; RSNC http://iside.rm.ingv.it) and DPC (RAN, www.protezionecivile.it; http://itaca.mi.ingv.it). The 2008 and 2012 Parma events, both characterized by reverse focal mechanisms (http://cnt.rm.ingv.it/), have depths of 27 and 60 km respectively. The deep event produced a maximum peak ground acceleration (PGA) of 97 cm/s2 at Novellara (NVL, EC8 C class) station (70 km from the epicenter). The 25th January 2012 event (depth of 34 km) produced a maximum PGA of 114 cm/s2 at Sorbolo (SRP) station (7 km from the epicenter). Preliminary analyses show: 1) a peculiar ground-motion attenuation of the deep Parma event with respect to the shallow one. In panel 2, the PGAs for the two Parma events are plotted as a function of hypocentral distance and compared to the global ground motion prediction equation (GMPE) calibrated by Cauzzi and Faccioli (2008) using events with depth < 30 km. The different distance-decay of PGA for the deep event (blue for A class of EC8 and red for B and C classes, CEN 2003) is evident, in particular for distance up to 100 km. On the other hand, the PGAs of the 2008 Parma crustal event (grey) are well explained by this GMPE. In panel 3, the PGAs for the deep 2012 event, grouped for EC8 classes, are compared to the national GMPE calibrated by Bindi et al. (2011) using crustal events and epicentral distance. Also in this case, the GMPE underestimates the PGAs up to 200 km. Although most of the class C sites (red) show the largest PGAs, the underestimation cannot be completely ascribed to site effects. The large PGAs from the Parma deep event, with respect to the shallow one, could be explained in terms of source effects (e.g. large stress drop values enhancing the high-frequency radiation). In addition, as explained by Castro et al. (2008), the different attenuation in the lower and upper crust could explain the large PGAs recorded for the 2012 deep event. 2) seismic amplification at Po Plain sites: In panel 4, the PGAs of the January 25th, Mw 4.9, Reggio Emilia event are plotted as a function of the epicentral distance, together with the Bindi et al. (2011) GMPE. In general, the largest amplitudes occur at the Po plain sites (red), suggesting possible peculiar site response. An overall increase of the PGAs is observed around 100km, in agreement with the results of Bragato et al. (2011) that studied the regional influence of Moho S-wave reflections in the area. An example of site response is shown in panel 5, considering TREG (class C) and ZEN8 (class A) stations (panel 5a), located at 88 km from the Reggio Emila epicentre. The rotational standard spectral ratio (panel 5b) for 10 s of S wave shows polarized amplifications around 2 Hz, detected also at others Po plain sites (not reported), as well as amplification on the vertical component. The points discussed above should to be interpreted as a warning for future applications dealing with ground motion estimation in the aftermath of an earthquake in this area (e.g. ShakeMap calculation): currently used GMPEs, based on different events and sites characteristics could lead to significant bias in the final results