Application of biochar as an additive to enhance biomethane potential in anaerobic digestion

Energy and useful materials can be produced by applying biological and thermal conversion processes such as anaerobic digestion and pyrolysis. Agricultural and industrial wastes seem to be the most attractive substrates since they are essentially unlimited resources. Pyrolysis has been used mostly for the conversion of biomass to bio-crude and biochar, a stable form of nearly pure carbon that has application in many agricultural and environmental applications. There is a widespread literature describing use of biochar as an additive to stabilize the anaerobic digestion process. We studied the effects that biochar has on the biomethane potential (BMP) during anaerobic digestion of a model food waste under mesophilic conditions (37ºC). Mixed food waste (FW) and dry manure (DM) were first converted into biochar at 500 and 800ºC using a laboratory pyrolysis furnace. Biochar loadings of 0, 0.5, 1, and 2 %g/gVS were added into 500 mL digester vessels. It was found that biochar provides enhanced stability when added to AD because biochar acts as a buffer in the system. Food waste biochar produced at 500ºC with a loading of 1% resulted in an increase of 11.7% in BMP when compared to the control. It was determined that biochar produced at lower temperature has lower pH and a greater effect in the upgrading of biomethane. Based on the experimental results, a techno-economic analysis (TEA) model was developed to understand the value that adding biochar would have to an operating digester, assuming a 10% enhancement in methane production with 1% biochar addition, based on the total mass of waste processed. The model included a sensitivity analysis in which an increase in food waste loading of 1, 5, 10 and 20% to the AD system was studied. The TEA revealed that food waste tipping fees drive the economics of working AD systems and that the addition of biochar has the possibility of boosting the economics for scenarios where biochar is purchased at low to mid-range prices, or when a pyrolysis system is installed on-site to produce biochar

Improved Bounds on Information Dissemination by Manhattan Random Waypoint Model

With the popularity of portable wireless devices it is important to model and predict how information or contagions spread by natural human mobility -- for understanding the spreading of deadly infectious diseases and for improving delay tolerant communication schemes. Formally, we model this problem by considering $M$ moving agents, where each agent initially carries a \emph{distinct} bit of information. When two agents are at the same location or in close proximity to one another, they share all their information with each other. We would like to know the time it takes until all bits of information reach all agents, called the \textit{flood time}, and how it depends on the way agents move, the size and shape of the network and the number of agents moving in the network. We provide rigorous analysis for the \MRWP model (which takes paths with minimum number of turns), a convenient model used previously to analyze mobile agents, and find that with high probability the flood time is bounded by $O\big(N\log M\lceil(N/M) \log(NM)\rceil\big)$, where $M$ agents move on an $N\times N$ grid. In addition to extensive simulations, we use a data set of taxi trajectories to show that our method can successfully predict flood times in both experimental settings and the real world.Comment: 10 pages, ACM SIGSPATIAL 2018, Seattle, U

Motion Textures: Modeling, Classification, and Segmentation Using Mixed-State Markov Random Fields

published_or_final_versio

Generation of Nanomaterials by Reactive Laser Synthesis in Liquid

Nanomaterials with tailored structures and surface chemistry are in high demand, as these materials play increasingly important roles in biology, catalysis, energy storage, and manu- facturing. Their heightened demand has attracted attention towards the development of syn- thesis routes, particularly, laser-synthesis techniques. These efforts drove the refinement of laser ablation in liquid (LAL) and related methods over the past two decades, and have led to the emergence of reactive laser-synthesis techniques that exploit these methods’ character- istic, non-equilibrium conditions. Reactive laser-synthesis approaches foster unique chemical reactions that enable the formation of composite products like multimetallic nanoparticles, supported nanostructures, and complex minerals. This review will examine emerging reac- tive laser-synthesis methods in the context of established methods like LAL. The focus will be on the chemical reactions initiated within the laser plasma, with the goal of understanding how these reactions lead to the formation of unique nanomaterials. We will provide the first systematic review of laser reaction in liquid (LRL) in the literature, and bring a focus to the chemical reaction mechanisms in LAL and reactive-LAL techniques that have not yet been em- phasized in reviews. Discussion of the current challenges and future investigative opportunities into reactive laser-synthesis will impart guidance for researchers interested in designing reactive laser-synthesis approaches to novel nanomaterial production

Génération d'intervalles discrets avec distribution quasi de Poisson

On présente une méthode pour obtenir des intervalles discrets, aléatoires, selon une distribution proche de la loi de Poisson de paramètre 1 . On opère en discrétisant des intervalles tirés suivant une loi de Poisson de paramètre k . Le processus obtenu a les mêmes deux premiers moments que la loi de Poisson que l'on veut approcher . Outre le paramètre k il dépend d'un « coefficient d'approximation » E lié à la discrétisation des intervalles . Cette méthode est utilisable sous la condition A . T < 2, T étant le pas de quantification des intervalles . Elle a été mise au point pour permettre la simulation numérique des instants qui, sur un électroencéphalogramme, correspondent à l'apparition de petits mouvements musculaires .A method for generating random discrete intervals with a pseudo-Poisson distribution, is described . The resulting process has the saure first and second order statistics as the continuous one before quantization. This is accomplished by using a roundoff coefficient E and changing the mean value X of the original process. The method is valid for values of X T < 2, where T is the quantization interval . The experimental purpose of this method is the simulation of the instants of occurrence of muscle artifacts in an EEG

Food Insecurity in Portugal Among Middle- and Older-Aged Adults at a Time of Economic Crisis Recovery: Prevalence and Determinants

Background: To characterize the scenario of food insecurity in Portugal at a time of economic crisis recovery is of the utmost relevance. Objective: This study aimed to estimate the prevalence and to identify the determinants of food insecurity during economic crisis recovery in a population-based urban sample of middle- and older-aged Portuguese adults. Methods: A cross-sectional study including 604 participants of the EPIPorto cohort was conducted. Data on sociodemographic characteristics and on food security status were collected. Food security status was assessed using the US Household Food Security Survey Module: Six-Item Short Form. Logistic regression models, crude and adjusted for sex, age, education, and household income perception, were performed. Results: The prevalence of food insecurity was 16.6%. Women (odds ratio [OR] = 1.96; 95% confidence interval [CI]: 1.09-3.54), those less educated (OR = 5.46; 95% CI: 2.84-10.46), and those who had the perception of an insufficient household income (OR = 10.39; 95% CI: 5.00-21.56) were more likely to belong to a food insecure household. Unmarried individuals (OR = 1.79; 95% CI: 1.05-3.06) and lower white-collar workers (OR = 2.22; 95% CI: 1.03-4.77) were also more prone to live within a food insecure household, regardless of sex, age, education, and household income perception. Conclusions: The obtained information is valuable for the development of intervention strategies to reduce food insecurity in middle- and older-aged adults, suggesting that women, unmarried, less educated individuals, less skilled workers, and lower income families should be targeted.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by contributions from Iceland, Liechtenstein, and Norway through the European Economic Area Grants, under the Public Health Initiatives Programme (PT 06, grant number 118SI2). This study was also funded by the Unidade de Investigação em Epidemiologia - Instituto de Saúde Pública da Universidade do Porto (EPIUnit) (POCI-01-0145-FEDER-006862; Ref.UID/DTP/04750/2013), the PhD Grant SFRH/BD/117371/2016 (IM), PhD Grant SFRH/BD/92370/2013 (TM), and the Postdoc Grant SFRH/BPD/88729/2012 (RL)), co-funded by the FCT and the POCH/FSE Program; and the FCT Investigator contract IF/01060/2015 (ACS). This study is also a result of the project DOCnet (NORTE-01- 0145-FEDER- 000003) supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF)

Discriminatory ability of next-generation tau PET tracers for Alzheimer's disease

A next generation of tau PET tracers for imaging of Alzheimer’s disease and other dementias has recently been developed. Whilst the new compounds have now entered clinical studies, there is limited information available to assess their suitability for clinical applications. Head-to-head comparisons are urgently needed to understand differences in the radiotracer binding profiles. We characterised the binding of the tau tracers PI2620, RO948, MK6240 and JNJ067 in human post-mortem brain tissue from a cohort of 25 dementia cases and age-matched controls, using quantitative phosphorimaging with tritium labelled radiotracers in conjunction with phospho-tau specific immunohistochemistry. The four tau radiotracers depicted tau inclusions composed of paired helical filaments with high specificity, both in cases with Alzheimer’s disease and in primary tauopathy cases with concomitant Alzheimer’s disease pathology. In contrast, cortical binding to primary tauopathy cases without paired helical filament tau was found to be within the range of age-matched controls. Off-target binding to monoamine oxidase B has been overcome, as demonstrated by heterologous blocking studies in basal ganglia tissue. The high variability of cortical tracer binding within the Alzheimer’s disease group followed the same pattern with each tracer, suggesting that all compounds are suited to differentiate Alzheimer’s disease from other dementias

Investigation Into the Humaneness of Slaughter Methods for Guinea Pigs (Cavia porcelus) in the Andean Region

Guinea pigs (Cavia porcelus) are an important source of nonhuman animal protein in the Andean region of South America. Specific guidelines regarding the welfare of guinea pigs before and during slaughter have yet to be developed. This study critically assessed the humaneness of 4 different stunning/slaughter methods for guinea pigs: cervical neck dislocation (n = 60), electrical head-only stunning (n = 83), carbon dioxide (CO(2)) stunning (n = 21), and penetrating captive bolt (n = 10). Following cervical neck dislocation, 97% of guinea pigs had at least 1 behavioral or cranial/spinal response. Six percent of guinea pigs were classified as mis-stunned after electrical stunning, and 1% were classified as mis-stunned after captive bolt. Increased respiratory effort was observed during CO(2) stunning. Apart from this finding, there were no other obvious behavioral responses that could be associated with suffering. Of the methods assessed, captive bolt was deemed the most humane, effective, and practical method of stunning guinea pigs. Cervical neck dislocation should not be recommended as a slaughter method for guinea pigs