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1.
Bioresour Technol ; 329: 124919, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33676353

RESUMEN

Links between synergy and microbial community characteristics in co-digestion of food waste (FW), cattle manure (CM) and corn straw (CS) were investigated. Mono-digestion of FW and CS were inhibited by organic acids. Co-digestion of FW with CM achieved greater synergistic rates (18.5% and 22.3%) than CM with CS (14.8% and 12.3%). Synergy resulted from coupling effects of improving nutrient balance, dilution of toxic compounds, higher buffering capacity, detoxification based on co-metabolism, which ultimately reflected in microbial community functions. Although co-digestion of FW with CS exhibited lowest synergistic rates (7.9% and 4.9%), detoxification based on co-metabolism of syntrophic communities of Syntrophomonadaceae with hydrogenotrophic methanogens accelerated system recovery. Digester with the greatest synergy (65% FW + 35% CM) maintained dominant growth of hydrogenotrophic methanogens (68.9%), highest methanogenic community diversity and relative abundance of Methanosarcina (14.6%), which sustained more diverse and switchable methanogenic pathways therefore ensured powerful methanogenic functions and vigorous methanogenic capability.


Asunto(s)
Microbiota , Eliminación de Residuos , Anaerobiosis , Animales , Biocombustibles , Reactores Biológicos , Bovinos , Digestión , Alimentos , Estiércol , Metano , Zea mays
2.
J Environ Manage ; 279: 111772, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-33310238

RESUMEN

This study investigated responses of anaerobic digestion (AD) of food waste (FW) with different inocula to varying organic loads and to pH control under high load in terms of process performance and microbial characteristics. Without pH control, digester inoculated by thickened sludge obtained high methane yield of 547.8 ± 27.8 mL/g VS under organic load of 7.5 g VS/L but was inhibited by volatile fatty acids (VFAs) under higher loads (15 and 30 g VS/L). However, digesters inoculated by anaerobic sludge obtained high methane yields of 575.9 ± 34.2, 569.3 ± 24.8 and 531.9 ± 26.2 mL/g VS under organic loads of 7.5, 15 and 30 g VS/L and VFAs inhibition only appeared under extremely high load of 45 g VS/L. Digesters under VFA inhibition with high load were significantly enhanced by controlling single ecological factor pH at 6.5, 7.0 and 7.5, as indicated by shorter lag phases, higher peak values of methane production rate, greater methane yields and fast VFAs degradation. Maximum methane recovery was obtained with pH control at 7.5 under high load. VFA inhibition was accompanied by the degeneration of ecological functions of Syntrophomonadaceae and unidentified Bacteroidales and the dominant growth of unidentified Clostridiales. Under high load and pH control, high stability was strongly associated with obvious growth of Methanosarcina, which enriched methanogenic pathways thus improved system robustness and tolerance to VFAs. Moreover, pH control stimulated the growth of syntrophic Bacteria Syntrophomonadaceae while maintaining the high activity of hydrogenotrophic methanogens therefore sustained efficient syntrophic communities of Bacteria and methanogens and avoided over accumulation of VFAs. pH control promoted adaptive selection of methanogens, leading to obvious decline of archaeal community diversity. This study provided practical guidance on digester configurations of high-load AD of FW and expanded the understanding of responses to coupling effects of inoculum origins, organic loads and pH control under high load concerning process performance and microbial community dynamics.


Asunto(s)
Reactores Biológicos , Eliminación de Residuos , Anaerobiosis , Alimentos , Concentración de Iones de Hidrógeno , Metano
3.
Ying Yong Sheng Tai Xue Bao ; 31(11): 3621-3630, 2020 Nov.
Artículo en Chino | MEDLINE | ID: mdl-33300711

RESUMEN

Forests play an important role in terrestrial carbon cycles. The mechanism underlying carbon balance in temperate deciduous broad-leaved forests is not clear. In this study, net ecosystem exchange (NEE) and environmental factors, including air temperature (Ta), soil temperature (Ts), photosynthetically active radiation (PAR), vapor pressure deficit (VPD), soil water content (SWC) and precipitation (P) were continually measured using eddy covariance techniques in 2019 in a deciduous broad-leaved forest in Songshan, Beijing. We analyzed the characteristics of NEE and its response to environmental factors. The results showed that, at diurnal scale, the monthly averaged NEE exhibited a "U" shape curve (i.e., being a carbon sink over daytime while being a carbon source during nighttime) over the growing season. During the non-growing season, NEE was positive (i.e., carbon source) at diurnal scale. At the seasonal scale, NEE exhibited a unimodal curve. The annual cumulative NEE was -111 g C·m-2·a-1. Annual ecosystem respiration was 555 g C·m-2·a-1, while gross ecosystem productivity was 666 g C·m-2·a-1. Carbon sequestration peaked in June, while emission peaked in November. PAR was the dominant factor affecting daytime NEE (NEEd). VPD was the main factor that indirectly affected daytime NEEd, with an optimal VPD value that maximizes daytime NEE around 1-1.5 kPa. Soil temperature was the main factor affecting nighttime NEE (NEEn). SWC was a limiting factor for NEEn. Too high or too low SWC would inhibit NEEn, with an optimal SWC value of 0.28 m3·m-3.

4.
ACS Omega ; 5(38): 24467-24476, 2020 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-33015463

RESUMEN

Recycling the phosphorus in sludge by incineration has received great interest at home and abroad. However, heavy metals (HMs) is a restrictive factor for SS thermal treatment. In this study, a comprehensive evaluation method was adopted to evaluate the comprehensive control efficiency of HM emissions during two-step thermal treatment (incineration-calcination). The effects of temperature, calcination time, and additives (CaO and NaCl) on leaching rates, stabilized rates, and comprehensive control efficiency of HM emissions were investigated. Results showed that comprehensive control efficiency increased significantly with an increase of temperature because of the transformation of chemical speciation from a leachable to a more stable combined form. Additives Cao and NaCl promoted the volatilization of HMs and reduced the comprehensive control efficiency. The highest comprehensive control efficiency of HM emissions was 78% when the incineration temperature reached 950 °C. Furthermore, a comparison was made between leaching rates, stabilized rates, and a comprehensive evaluation method. The results were inconsistent when leaching rates and stabilized rates were adopted. In contrast, when the comprehensive evaluation method was used, the results were coordinated and unique. This work can provide a promising approach for the evaluation of control efficiency of HM emissions during the process of thermal treatment of sludge.

5.
R Soc Open Sci ; 7(8): 200079, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32968505

RESUMEN

Boron nitride, also known as white graphene, has attracted extensive attention in the fields of adsorption, catalysis and hydrogen storage due to its excellent chemical properties. In this study, a phosphorus-doped boron nitride (P-BN) material was successfully prepared using red phosphorus as a dopant for the preparation of porous boron nitride precursors. The phosphorus content in the P-BN was adjusted based on the addition rate of phosphorus. The specific surface area of P-BN first increased and then decreased with increasing addition rate of phosphorus. The maximum specific surface area was 837.8 m2 g-1 when the phosphorus addition rate was 0.50. The P-BN prepared in the experiments was used as an adsorbent, and its adsorption capacity for heavy metals from flue gas was investigated. In particular, P-BN presented a stronger adsorption selectivity for zinc compared with other heavy metals, and its adsorption capacity for zinc was 5-38 times higher than for other heavy metals. The maximum adsorption capacity of P-BN for zinc and copper in a single heavy metal atmosphere was 69.45 and 53.80 mg g-1, respectively.

6.
Bioresour Technol ; 315: 123796, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32682261

RESUMEN

Role of trace elements (TEs) in long-term anaerobic digestion of food waste (FW) under fixed and stepwise increasing loads and under early and medium volatile fatty acid (VFA) inhibition was investigated. Digesters under high load suffered VFA inhibition. Mismatch between scarce TEs in FW and essential TEs for sustainable methanogenesis suppressed Methanosaeta causing blocked aceticlastic methanogenesis and shift to CO2 reduction pathway, as indicated by decreased Methanosaeta from above 70.0% to below 42.0% and enriched hydrogenotrophic methanogens (Methanospirillum, Methanoculleus, Methanobacterium) from below 15.0% to above 53.6%. Dual stresses of VFA inhibition and TEs deficiency resulted in recession of syntrophic Bacteria Syntrophomonadaceae. Conversely, digesters with TEs supplementation maintained high activity of Syntrophomonadaceae and ensured predominant aceticlastic methanogenesis and powerful methanogenic community functions. Early and medium VFA inhibition were reversed by TEs supplementation or coupling with pH adjustment by stimulating VFAs degradation via syntrophic metabolism and unclogging acetate conversion via aceticlastic methanogenesis.


Asunto(s)
Microbiota , Eliminación de Residuos , Oligoelementos , Anaerobiosis , Reactores Biológicos , Metano
7.
Biomed Res Int ; 2020: 1754134, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32190651

RESUMEN

Proteins are the most important component in sludge extracellular polymeric substances (EPS) and play a crucial role in the formation of sludge flocs, adsorption performance of sludge, and flocculation ability of sludge. This research is aimed at exploring the changes in proteins in EPS extracted from concentrated sludge after various nanoparticle (NP) treatments. The results showed that the protein content in EPS decreased by 40% after nanoalumina (Al2O3 NPs) treatment but increased at varying degrees after nanoferric oxide (Fe3O4 NPs), nanozinc oxide (ZnO NPs), and nanotitanium dioxide (TiO2 NPs) treatments. The four kinds of nanoparticles not only affected the protein content in EPS but also influenced the types and structures of proteins. The results of three-dimensional fluorescence spectroscopy showed that the tyrosine-like protein content in soluble EPS (SEPS) decreased after treatments with four kinds of NPs. Infrared spectroscopy analysis revealed that the absorption intensity of amide I and amide II weakened after Al2O3 NP treatment, whereas that of amide I enhanced after Fe3O4 NP, ZnO NP, and TiO2 NP treatments. Further analysis of the secondary structure of proteins in the infrared range of 1700-1600 cm-1 demonstrated that the value of α-helix/(ß-sheet+random coil) decreased from 0.513 to 0.383 in SEPS after TiO2 NP treatment. For the samples treated by Fe3O4 NPs, the percentage of α-helix significantly increased and that of ß-sheet slightly decreased in proteins from SEPS and loosely bound EPS.

8.
Sci Total Environ ; 710: 136346, 2020 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-31923688

RESUMEN

Extracellular polymeric substances (EPS) play an important role in reducing moisture content and removing heavy metals from municipal sludge. In this study, cetyl trimethyl ammonium bromide (CTAB) and primary alcohol ethoxylate (AEO9) were used to prepare complex surfactants. Municipal sludge was treated with mixed surfactants and hydrothermal treatment (HTT) to test the sludge dewatering and heavy metal adsorption performance of EPS treated with varying proportions and contents of surfactants. The results showed that EPS with different proportions had different adsorption capacities for major heavy metals in sludge was 20.48%-29.82%. The adsorption capacity of EPS on heavy metals is significantly positively correlated with protein content (R2 = 0.9266, P = .00). There is no significant correlation between polysaccharides (R2 = 0.0092, P = .00) and nucleic acids (R2 = 0.0638, P = .00) and heavy metal adsorption capacity. Combined treatment of 10% CTAB, 15% AEO9, and HTT produced the minimal bound water content in treated sludge, zeta potential increased by 49.2 mV and sludge specific resistance is only 0.66% of the raw sludge.

9.
Environ Sci Pollut Res Int ; 26(29): 29917-29929, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31410836

RESUMEN

Phosphorus (P), an irreplaceable nutrient for all living organisms, is facing scarcity via phosphate resources. In this research, the effect of suitable additives and temperature on P and heavy metals speciation during sewage sludge (SS) thermochemical treatment was investigated. The results demonstrated that additives (CaO and MgO) could promote the conversion of non-apatite inorganic phosphorus (NAIP) to apatite phosphorus (AP). X-ray diffraction measurements indicated that the phosphorus mineral phase in sewage sludge ash (SSA) mainly was AP, with addition of MgO and CaO. Moreover, orthogonal testing revealed that the optimal molar ratio of Mg:Ca:P for P recovery as AP was 1:3.5:1 at 750 °C. Risk index results implied that the heavy metals in the phosphorus-enriched SSA have low potential ecological risk. Thermodynamic equilibrium calculations revealed that P reacted with the other metal ions was in the following order: Ca2+ > Mg2+ > Al3+ > Fe3+ > Zn2+ > K+. Graphical Abstract.


Asunto(s)
Incineración/métodos , Metales Pesados/química , Fosfatos/química , Fósforo/química , Aguas del Alcantarillado/química , Apatitas/química , Calor , Difracción de Rayos X
10.
Water Environ Res ; 91(10): 1150-1167, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31433884

RESUMEN

The management of agricultural waste has become very important because the inappropriate disposal yields negative effects on the environment. The resource recovery from agricultural waste which converts waste into available resources can reduce the waste and new resource consumption. This review summarizes the 2018 researches of over three hundred scholar papers from several aspects: agricultural waste, and, waste chemical characterization, agricultural waste material, adsorption, waste energy, composting, waste biogas, agricultural waste management, and others.


Asunto(s)
Compostaje , Administración de Residuos , Agricultura , Biocombustibles , Residuos
11.
J Biosci Bioeng ; 128(6): 733-743, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31231036

RESUMEN

This study characterized dynamic behaviors of batch anaerobic digesters treating food waste in terms of methane production, organics destruction and process stability under different organic loads (OLs), substrate to inoculum (S/I) ratios [on volatile solid (VS) basis] and initial pH. The results showed that OL, S/I ratio and initial pH significantly affected batch anaerobic process. Methane yield was proved to be inversely proportional to OL and S/I ratio. Digester with lowest OL (5 g VS/L) obtained greatest methane yield (551.4 mL/g VS), highest organics removal (94.1%) and good stability. Enhancing OL to 10 g VS/L was recommended for satisfactory stability and higher volumetric methane productivity. When OL was designated as 10 g VS/L, digester with low S/I ratio (1/2) achieved satisfactory methane yield (539.3 mL/g VS), high organics removal (92.3%) and stable performance. When OL was relatively high (20 g VS/L), adjusting initial pH to 7.5 contributed to stable performance via enhancing buffering capacity against volatile fatty acids (VFA) disturbance. Strong VFA inhibition occurred under high OL (40 g VS/L) or great S/I ratio (2/1) or acidic initial pH (6.5). In this case, acetate was dominant VFA, followed by butyrate. However, when digester was stable, acetate was main VFA, followed by propionate. This study provided practical guidance on process configurations for batch digesters of food waste needed to achieve satisfactory performance and stability.


Asunto(s)
Alimentos , Metano/biosíntesis , Anaerobiosis , Reactores Biológicos , Ácidos Grasos Volátiles/metabolismo , Concentración de Iones de Hidrógeno , Eliminación de Residuos
12.
Environ Sci Pollut Res Int ; 26(11): 10875-10886, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30778942

RESUMEN

The sewage sludge contains abundant organic substances as well as a complex variety of inorganic substances (such as heavy metals). The extraction of protein from sludge is a new treatment approach to promote the utilization of sludge as a resource. However, heavy metals in sludge are extracted together with organic matter during the extraction process. In this study, the amounts of protein and heavy metal in the supernatant extracted from sewage sludge were investigated, and the effects of different passivator (modified fly ash and modified sepiolite) on the speciation of different heavy metals in the sludge were examined. Both materials reduced the contents of protein and heavy metal in the supernatant. When the dosage of sepiolite was 0.10 g/g total suspended solids of sludge, the content of heavy metals was the lowest and the protein content had little change. It can be deduced by analysis of specific area that sepiolite can complex with heavy metal ions and the fly ash adsorb the metals by physical adsorption. The modified sepiolite can be seen as an ideal passivator due to higher protein content and less heavy metals in the supernatant, as well as more stable heavy metals in the sediments.


Asunto(s)
Ceniza del Carbón/química , Silicatos de Magnesio/química , Metales Pesados/análisis , Proteínas/análisis , Aguas del Alcantarillado/análisis , Eliminación de Residuos Líquidos/métodos
13.
Environ Sci Pollut Res Int ; 26(9): 9123-9136, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30719670

RESUMEN

A lightweight aggregate (LWA) was manufactured from municipal sewage sludge, gangue, and coal ash. The product performance and environmental safety of the sintered material were evaluated by changing the sludge blending ratio and sintering temperature. The distribution and migratory transformation characteristics of heavy metals in LWA were examined by BCR sequential extraction in combination with inductively coupled plasma optical emission spectrometry (ICP-OES). The environmental safety performance of LWA was comprehensively evaluated by the OPTI index for the first time. The leaching concentration of the heavy metals Pb, Ni, Cu, and Zn in raw materials without sintering reached 1.17, 1.6, 7.84, and 7.56 mg/L, respectively, far exceeding the regulatory threshold value. At 1250 °C, sintering with 60% sludge content resulted in Cu and Zn leaching concentrations of only 0.41 mg/L and 0.37 mg/L, respectively. Furthermore, a big portion of heavy metals were in the residual fraction of sintered LWA. The proportion of comprehensive pollutant toxicity index is only 199.17. Additionally, the mechanical properties of sintered LWA exceed the standards stipulated in the GB/T1743.1-2010 standard. Using sewage sludge to manufacture lightweight aggregate is not only environmentally safe but also produces LWA with good engineering characteristics.


Asunto(s)
Metales Pesados/química , Aguas del Alcantarillado/química , Ceniza del Carbón/química , Contaminantes Ambientales/química , Contaminantes Ambientales/toxicidad , Metales Pesados/toxicidad , Reciclaje , Temperatura , Residuos/análisis
14.
Distrib Parallel Databases ; 37(3): 411-439, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31889741

RESUMEN

We consider data analytics workloads on distributed architectures, in particular clusters of commodity machines. To find a job partitioning that minimizes running time, a cost model, which we more accurately refer to as makespan model, is needed. In attempting to find the simplest possible, but sufficiently accurate, such model, we explore piecewise linear functions of input, output, and computational complexity. They are abstract in the sense that they capture fundamental algorithm properties, but do not require explicit modeling of system and implementation details such as the number of disk accesses. We show how the simplified functional structure can be exploited to reduce optimization cost. In the general case, we identify a lower bound that can be used for search-space pruning. For applications with homogeneous tasks, we further demonstrate how to directly integrate the model into the makespan optimization process, reducing search-space dimensionality and thus complexity by orders of magnitude. Experimental results provide evidence of good prediction quality and successful makespan optimization across a variety of operators and cluster architectures.

15.
Bioresour Technol ; 275: 172-182, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30584962

RESUMEN

This study investigated mechanism of process imbalance of long-term anaerobic digestion (AD) of food waste (FW) and role of trace elements (TEs) in maintaining process stability. AD of FW was strongly inhibited by volatile fatty acids (VFA, mainly propionate). The deficiency of essential TEs in FW was the fundamental reason. TEs contents in digester gradually decreased with regular substrate feeding and digestate discharge, which greatly limited growth and metabolism of hydrogenotrophic methanogens and Methanosarcina. Finally, Methanosaeta replaced Methanosarcina and became dominant methanogen and hydrogenotrophic methanogens almost disappeared accompanied by declining methanogenic community diversity, which greatly suppressed ecological functions of methanogens and led to propionate inhibition. TEs supplementation eliminated all factors causing process imbalance and significantly enhanced process stability by maintaining strong ecological functions of methanogens via stimulating dominant growth of Methanosarcina (relative abundance between 67.2% and 87.5%), sustaining stable relative abundances of hydrogenotrophic methanogens (about 10%) and enhancing methanogenic community diversity.


Asunto(s)
Oligoelementos/metabolismo , Anaerobiosis , Reactores Biológicos , Methanosarcina/metabolismo
16.
Huan Jing Ke Xue ; 39(6): 2786-2793, 2018 Jun 08.
Artículo en Chino | MEDLINE | ID: mdl-29965636

RESUMEN

Sewage sludge is rich in organic matter, N, and P and could be used as a soil amendment to improve the status of soil organic matter, soil structural characteristics, and soil water retention capacity after aerobic composting. However, heavy metals in sewage sludge have become the main bottleneck limiting its land application. In addition, with the large-scale exploitation of phosphate rock resources in our region of interest, a large amount of phosphate tailings needs to be disposed and a large area of abandoned mining lands needs to be reclaimed. Phosphate tailings could be auxiliary materials for sewage sludge composting to immobilize heavy metals, and the compost could be applied for revegetation of the abandoned mining lands. The contents of As, Cr, Cu, Ni, Pb, Cd, and Zn were measured, and a successive extraction procedure was used to investigate the change in speciation of heavy metals in the sludge before and after the phosphate-rich composting. pH-dependent leaching tests were carried out to further evaluate the immobilization effects of composting on heavy metals and the release potential under different pH conditions. The results showed that the contents of heavy metals in the compost satisfied the corresponding threshold for land reclamation. Adding phosphate tailings greatly improved the stability of heavy metals during the composting process. The portion of stable residues of Pb, Cd, As, and Zn in the phosphate-rich compost was 84.00%, 58.00%, 68.50%, and 30.93%, respectively, compared with 68.10%, 30.50%, 40.32%, and 16.48% for the control, compost without adding the phosphate tailings. Meanwhile, the maximum leaching potential of As, Ni, Pb, Zn, and Cu in the phosphate-rich compost decreased from 3.692 mg·kg-1, 0.903 mg·kg-1, 0.217 mg·kg-1, 7.225 mg·kg-1, and 8.725 mg·kg-1 to 0.684 mg·kg-1, 0.586 mg·kg-1, 0.071 mg·kg-1, 2.603 mg·kg-1, and 6.935 mg·kg-1in the control, respectively, for pH 6-8.It could be concluded that the addition of phosphate tailings in the sludge composting lowered the risk of heavy metals in sewage sludge compost to make it favorable for beneficial use in abandoned mining land reclamation.


Asunto(s)
Compostaje , Metales Pesados/química , Fosfatos/química , Aguas del Alcantarillado/química , Contaminantes del Suelo/química , Atmósfera , Suelo
17.
Huan Jing Ke Xue ; 39(1): 292-299, 2018 Jan 08.
Artículo en Chino | MEDLINE | ID: mdl-29965695

RESUMEN

Fly ash from sludge incineration was separated into five different sizes (<1 µm, 1-2.5 µm, 2.5-10 µm, 10-50 µm, and > 50 µm) by high-precision air classification equipment. The leaching of heavy metals was contrastively studied using the HJT 299-2007-sulfuric acid/nitric acid method, HJ 557-2009-Horizontal Oscillation Method, toxicity characteristic leaching procedure (TCLP), and European standard protocol (EN 12457-3) for the different size fractions of the fly ash. Based on the leaching results, an evaluation method for the comprehensive toxicity of heavy metal leaching was established. The results show that the content of heavy metals and the amount of leaching from the fly ash decrease with the increase in fly ash particle size. The leaching of the heavy metals Zn and Cu in the < 1 µm particle size range of TCLP leaching method was the highest, at 107.34 mg·kg-1 and 318 mg·kg-1, respectively. The TCLP and sulfuric acid/nitric acid methods of heavy metal leaching were more effective than the EU (EN 12457-3) and horizontal oscillation methods. According to the value of OPTI, the OPTI value of < 10 µm fly ash was much larger than that of fly ash that was > 10 µm. This indicated that the fly ash of particle size < 10 µm was more toxic and more harmful.

18.
IEEE Trans Neural Netw Learn Syst ; 29(8): 3919-3924, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-29993608

RESUMEN

Recognizing scenes from synthetic aperture radar (SAR) images has been a challenging task due to the increasing resolution of SAR data. Extracting discriminative features from SAR images is extremely difficult for their sensitivity to target aspect. Considering the intractability of the available deep neural networks in practical implementations, in this brief, we propose a simple and efficient deep sparse tensor filtering network (DSTFN) for SAR image classification. An SAR image is first organized into a data tensor by an overlapped partition. Then, a set of dimension-inseparable geometric filters is developed from a least squares support vector machine, followed by a learned sparse filtering of tensors. Finally, the constructed sparse tensor filters are cascaded to a deep network to automatically extract the discriminative features of the image for accurate classification. Simulations are carried out to verify the effectiveness of the proposed DSTFN.

19.
Bioresour Technol ; 265: 82-92, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29883850

RESUMEN

This study investigated effects of real-time recovery strategies on VFA (volatile fatty acid)-inhibited anaerobic system of FW (food waste) and identified key driver of process recovery. The long-term anaerobic system of FW encountered serious VFA (mainly propionate) inhibition. The pH adjustment (PA) strategy could not reverse process imbalance but only delayed the process failure. The short-term effect of reinoculation (RI) strategy was greatly effective, but its long-term effect was non-sustainable. Trace elements were key drivers of process recovery owing to their indispensable roles in activating methanogenesis and therefore stimulating propionate conversion. From the viewpoint of economic feasibility, the single strategy of trace elements supplementation (TE) and the combinational strategy of PA + TE were respectively recommended in the initial and medium VFA-inhibition stages. The three-in-one strategy of PA + TE + RI was always effective but was costly. This study provided practical guidance on real-time recovery of VFA-inhibited anaerobic system of FW.


Asunto(s)
Reactores Biológicos , Ácidos Grasos Volátiles , Alimentos , Metano , Eliminación de Residuos , Anaerobiosis , Propionatos , Oligoelementos
20.
Appl Radiat Isot ; 139: 274-278, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-29879532

RESUMEN

One novel gamma spectrometry method based on short-lived fission products was developed that can infer the level of burnup without complex computations or knowing irradiation history. The relationship between the burnup information and equilibrium concentration of short-lived indicators was derived. In addition, new candidate indicators for gamma spectrum analysis, such as 88Kr, 91Sr, 92Sr, 135I and 142La were screened out. The results of three cases simulated with ORIGEN and MCNP were in good agreement with the theoretical values.

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