Breakdown of biomass for energy applications using microwave pyrolysis: A technological review

The agricultural industry faces a permanent increase in waste generation, which is associated with the fast-growing population. Due to the environmental hazards, there is a paramount demand for generating electricity and value-added products from renewable sources. The selection of the conversion method is crucial to develop an eco-friendly, efficient and economically viable energy application. This manuscript investigates the influencing factors that affect the quality and yield of the biochar, bio-oil and biogas during the microwave pyrolysis process, evaluating the biomass nature and diverse combinations of operating conditions. The by-product yield depends on the intrinsic physicochemical properties of biomass. Feedstock with high lignin content is favourable for biochar production, and the breakdown of cellulose and hemicellulose leads to higher syngas formation. Biomass with high volatile matter concentration promotes the generation of bio-oil and biogas. The pyrolysis system's conditions of input power, microwave heating suspector, vacuum, reaction temperature, and the processing chamber geometry were influence factors for optimising the energy recovery. Increased input power and microwave susceptor addition lead to high heating rates, which were beneficial for biogas production, but the excess pyrolysis temperature induce a reduction of bio-oil yield

Nitrite sensor using activated biochar synthesised by microwave-assisted pyrolysis

Developing applications for the by-products obtained from waste processing is vital for resource recovery. The synthesis of ZnCl2-activated biochar with high electrocatalytic activity was carried out by the microwave-assisted pyrolysis of pineapple peel and subsequent chemical activation process. Activated biochar is employed in the electrochemical sensing of nitrite by drop casting in a glassy carbon electrode (GCE). The activated biochar exhibited a stacked carbon sheet, 254 m2 g−1 Brunauer, Emmett and Teller (BET) surface area, 0.076 cm3 g−1 pore volume, 189.53 m2 g−1 micropore area and oxygen-containing functional groups. The electrochemical impedance spectroscopy of the modified GCE showed a reduced charge transfer resistance of 61%. This is crucial to determine the electrochemical properties of biochar. The sensor showed a significant current response and an excellent limit of detection of 0.97 µmol L−1. The modified-activated biochar electrochemical sensor demonstrated high selectivity, reproducibility (RSD=2.4%), and stability (RSD=2.6%). Graphical abstract: [Figure not available: see fulltext.

Electrochemical sensing of oxalic acid using silver nanoparticles loaded nitrogen-doped graphene oxide

The adverse effects of oxalic acid (OA) on human health linked with its excessive consumption necessitates an improved sensor. Here, we demonstrate an electrochemical sensor for oxalic acid detection based on silver nanoparticles (Ag-Nps) and nitrogen-doped graphene oxide (N-GO) nanocomposite. N-GO, which was synthesized using atmospheric pressure microwave plasma has been first time employed for electrochemical application. The nanocomposite formation was confirmed through scanning electron microscopy and EDS elemental analysis. The nanocomposite-based sensor showed a higher current response, good selectivity and stability which can be attributed to the synergistic-effect of Ag-Nps and N-GO. Amperometric responses were proportional to the concentration of OA between 10 and 300 μM, and the detection limit was 2 μM

Predictor variables of the perception of success: Differential aspects in route runners

Se pretendía conocer qué relaciones predictivas presentaban la motivación, el compromiso a correr, la adicción negativa a correr y la ansiedad precompetitiva, sobre la percepción del éxito en una amplia muestra de 1795 corredores de fondo en ruta (1105 españoles, 690 mexicanos). De ellos el 85.65% fueron hombres con una edad de M=38.98 (DT=10.45), y 14.35% mujeres, con una edad M=37.88 (DT=9.80). La recogida de datos se llevó a cabo mediante las adaptaciones al castellano del Perception of Success Questionnaire (POSQ), Motivations of Marathoners Scales-34 (MOMS-34), Commitment to Running Scale-11 (CR-11) y Revised Competitive State Anxiety Inventory-2 (CSAI-2R). Se obtuvo que los valores en las orientaciones de meta de los corredores son medios y similares, aunque significativamente mayores en la muestra mexicana, debido a su mayor compromiso y motivaciones, así como a las diferencias culturales entre ambas nacionalidades. Los modelos predictores de la percepción del éxito obtenidos resultaron muy similares por nacionalidades, pero diferenciados por sexos, obteniendo altas varianzas explicativasWe pretended to find out which predictive relationships would be introduced by motivation, commitment to run, negative addiction to run and pre-competition anxiety, concerning the winning perception of a broad sample of 1795 track long-distance runners (1105 Spanish, 690 Mexicans). Of them, 85.65% were men, ages M=37.88 (SD=10.45) and 14.35% were women, ages M=37.88 (SD=9.80). The data was obtained by adapting to Spanish the following: “Perception of Success Questionnaire” (POSQ), “Motivations of Marathoners Scales-34 (MOMS-34), Commitment to Running Scale-11 (CR-11) and Revised Competitive State Anxiety Inventory-2 (CSAI-2R). The values obtained on the winning orientations of the runners were average and similar, although significantly higher in the Mexican sample, due to their higher commitment and motivation, as well as the cultural differences between these nationalities. The predicting models of the success perception obtained were very similar by nationality, but differentiated by sex, obtaining high explicatory variance

Chemical Abundances in Field Red Giants from High-Resolution H-Band Spectra using the APOGEE Spectral Linelist

High-resolution H-band spectra of five bright field K, M, and MS giants, obtained from the archives of the Kitt Peak National Observatory (KPNO) Fourier Transform Spectrometer (FTS), are analyzed to determine chemical abundances of 16 elements. The abundances were derived via spectrum synthesis using the detailed linelist prepared for the SDSS III Apache Point Galactic Evolution Experiment (APOGEE), which is a high-resolution near-infrared spectroscopic survey to derive detailed chemical abundance distributions and precise radial velocities for 100,000 red giants sampling all Galactic stellar populations. Measured chemical abundances include the cosmochemically important isotopes 12C, 13C, 14N, and 16O, along with Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu. A comparison of the abundances derived here with published values for these stars reveals consistent results to ~0.1 dex. The APOGEE spectral region and linelist is, thus, well-suited for probing both Galactic chemical evolution, as well as internal nucleosynthesis and mixing in populations of red giants using high-resolution spectroscopy.Comment: Accepted for publication in The Astrophysical Journal. 42 pages, 12 figure

The Observed Trend of Boron and Oxygen in Field Stars of the Disk

Oxygen abundances are derived in a sample of 13 field F and G dwarfs and subgiants with metallicities in the range of -0.75 < [Fe/H] < +0.15. This is the same sample of stars for which boron abundances have been derived earlier from archived spectra obtained with the Hubble Space Telescope. In a log-log comparison of the B versus the O abundances, a slope of m(BO)=1.39 is found, indicating that in the disk, the abundance of B relative to O is intermediate between primary and secondary production (hybrid behavior). This relation of B versus O for disk stars is compared to the same relation for halo stars.Comment: 14 pages, 3 figures, 1 table. In press to The Astronomical Journal (July 2001

The Space Interferometry Mission Astrometric Grid Giant-Star Survey. III. Basic Stellar Parameters for an Extended Sample

We present results of high resolution (~ 55000) spectral observations of 830 photometrically pre-selected candidate red giants in the magnitude range of V = 9-12. We develop a pipeline for automated determination of the stellar atmospheric parameters from these spectra and estimate T_eff, logg, [Fe/H], microturbulence velocity, and projected rotational velocities, vsini, for the stars. The analysis confirms that the candidate selection procedure yielded red giants with very high success rate. We show that most of these stars are G and K giants with slightly subsolar metallicity ([Fe/H] ~ -0.3 dex) An analysis of Mg abundances in the sample results in consistency of the [Mg/Fe] vs [Fe/H] trend with published results.Comment: Accepted by A

Beef cattle and sheep systems management: Computer tools to design and evaluate productive scenarios

The increase in the human population and its consumption of animal protein have led to greater complexity in defining integrative practices to develop efficient production systems. The biological and economic sustainability of livestock systems can be focused on two lines: the increase in the efficiency of resource use with an internal sufficiency of the system and the structuring of functional integral systems. Market liberalization, changing customer expectations, technological discontinuities, and global competition cause the sources of competitive advantage to shift, forcing companies to continually respond to the demands of a dynamic environment. The adoption of a quality-oriented management model is one of the alternatives that has been most successful in facing the challenges of this global and competitive environment. However, the orientation towards quality generally requires innovations that must be evaluated to verify if they create value in the company. Value creation assessment is a concept that has not been applied in-depth in the bovine and sheep production sector and is probably what explains the reluctance of producers to adopt innovative technological alternatives. Value creation is related to the approach with which the objectives of the company are approached, which have evolved from a single objective, which is the maximization of profit, to the most recent one in which the coexistence of a plurality of objectives is recognized. This diversity of objectives can be integrated into one, which is the maximization of the company's value in the market

12C/13C isotopic ratios in red-giant stars of the open cluster NGC 6791

Carbon isotope ratios, along with carbon and nitrogen abundances, are derived in a sample of 11 red-giant members of one of the most metal-rich clusters in the Milky Way, NGC 6791. The selected red-giants have a mean metallicity and standard deviation of [Fe/H]=+0.39+-0.06 (Cunha et al. 2015). We used high resolution H-band spectra obtained by the SDSS-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE). The advantage of using high-resolution spectra in the H-band is that lines of CO are well represented and their line profiles are sensitive to the variation of 12C/13C. Values of the 12C/13C ratio were obtained from a spectrum synthesis analysis. The derived 12C/13C ratios varied between 6.3 and 10.6 in NGC 6791, in agreement with the final isotopic ratios from thermohaline-induced mixing models. The ratios derived here are combined with those obtained for more metal poor red-giants from the literature to examine the correlation between 12C/13C, mass, metallicity and evolutionary status.Comment: Accepted for publication in MNRAS, 9 pages, 4 figures, 2 table