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1.
J Environ Manage ; 351: 120006, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38176383

RESUMEN

The performance of anaerobic digestion (AD) is susceptible to disturbances in feedstock degradation, intermediates accumulation, and methanogenic archaea activity. To improve the methanogenesis performance of the AD system, Fe-N co-modified biochar was prepared under different pyrolysis temperatures (300,500, and 700 °C). Meanwhile, pristine and Fe-modified biochar were also derived from alternanthera philoxeroides (AP). The aim was to compare the effects of Fe-N co-modification, Fe modification, and pristine biochar on the methanogenic performance and explicit the responding mechanism of the microbial community in anaerobic co-digestion (coAD) of AP and cow manure (CM). The highest cumulative methane production was obtained with the addition of Fe-N-BC500 (260.38 mL/gVS), which was 42.37 % higher than the control, while the acetic acid, propionic acid, and butyric acid concentration of Fe-N-BC were increased by 147.58 %, 44.25 %, and 194.06 % compared with the control, respectively. The co-modified biochar enhanced the abundance of Chloroflexi and Methanosarcina in the AD system. Metabolic pathway analysis revealed that the increased methane production was related to the formation and metabolism of volatile fatty acids and that Fe-N-BC500 enhanced the biosynthesis of coenzyme A and the cell activity of microorganisms, accelerating the degradation of propionic acid and enhancing the hydrogenotrophic methanogenesis pathway. Overall, Fe-N co-modified biochar was proved to be an effective promoter for accelerated methane production during AD.


Asunto(s)
Carbón Orgánico , Microbiota , Propionatos , Animales , Femenino , Bovinos , Anaerobiosis , Estiércol , Redes y Vías Metabólicas , Digestión , Metano , Reactores Biológicos
2.
J Environ Manage ; 356: 120604, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38518501

RESUMEN

This study aimed to explore the co-application of MnSO4 (Mn) and biochar (BC) in nitrogen conversion during the composting process. A 70-day aerobic composting was conducted using swine slurry, supplemented with different levels of Mn (0, 0.25%, and 0.5%) and 5% BC. The results demonstrated that the treatment with 0.5MnBC had the highest levels of NH4+-N (3.07 g kg-1), TKN (29.90 g kg-1), and NO3--N (1.94 g kg-1) among all treatments. Additionally, the 0.5MnBC treatment demonstrated higher urease, protease, nitrate reductase, and nitrite reductase activities than the other treatments, with the peak values of 18.12, 6.96, 3.57, and 15.14 mg g-1 d-1, respectively. The addition of Mn2+ increased the total organic nitrogen content by 29.59%-47.82%, the acid hydrolyzed ammonia nitrogen (AN) content by 13.84%-57.86% and the amino acid nitrogen (AAN) content by 55.38%-77.83%. The richness of Chloroflexi and Ascomycota was also enhanced by the simultaneous application of BC and Mn. Structural equation modeling analysis showed that Mn2+ can promote the conversion of Hydrolyzed Unknown Nitrogen (HUN) into AAN, and there is a positive association between urease and NH4+-N according to redundancy analysis. Firmicutes, Basidiomycota, and Mortierellomycota showed significant positive correlations with ASN, AN, and NH4+-N, indicating their crucial roles in nitrogen conversion. This study sheds light on promoting nitrogen conversion in swine slurry composting through the co-application of biochar and manganese sulfate.


Asunto(s)
Compuestos de Manganeso , Nitrógeno , Suelo , Sulfatos , Animales , Porcinos , Nitrógeno/metabolismo , Ureasa , Estiércol , Carbón Orgánico
3.
J Environ Manage ; 365: 121613, 2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-38944964

RESUMEN

Composting is a biological reaction caused by microorganisms. Composting efficiency can be adequately increased by adding biochar and/or by inoculating with exogenous microorganisms. In this study, we looked at four methods for dewatered sludge waste (DSW) and wheat straw (WS) aerobic co-composting: T1 (no additive), T2 (5% biochar), T3 (5% of a newly isolated strain, Xenophilus azovorans (XPA)), and T4 (5% of biochar-immobilized XPA (BCI-XPA)). Throughout the course of the 42-day composting period, we looked into the carbon dynamics, humification, microbial community succession, and modifications to the driving pathways. Compared to T1 and T2, the addition of XPA (T3) and BCI-XPA (T4) extended the thermophilic phase of composting without negatively affecting compost maturation. Notably, T4 exhibited a higher seed germination index (132.14%). Different from T1 and T2 treatments, T3 and T4 treatments increased CO2 and CH4 emissions in the composting process, in which the cumulative CO2 emissions increased by 18.61-47.16%, and T3 and T4 treatments also promoted the formation of humic acid. Moreover, T4 treatment with BCI-XPA addition showed relatively higher activities of urease, polyphenol oxidase, and laccase, as well as a higher diversity of microorganisms compared to other processes. The Functional Annotation of Prokaryotic Taxa (FAPROTAX) analysis showed that microorganisms involved in the carbon cycle dominated the entire composting process in all treatments, with chemoheterotrophy and aerobic chemoheterotrophy being the main pathways of organic materials degradation. Moreover, the presence of XPA accelerated the breakdown of organic materials by catabolism of aromatic compounds and intracellular parasite pathways. On the other hand, the xylanolysis pathway was aided in the conversion of organic materials to dissolved organics by the addition of BCI-XPA. These findings indicate that XPA and BCI-XPA have potential as additives to improve the efficiency of dewatered sludge and wheat straw co-composting.

4.
Sensors (Basel) ; 22(21)2022 Oct 29.
Artículo en Inglés | MEDLINE | ID: mdl-36366008

RESUMEN

In order to improve the initialization robustness of visual inertial SLAM, the complementarity of the optical flow method and the feature-based method can be used in vision data processing. The parallel initialization method is proposed, where the optical flow inertial initialization and the monocular feature-based initialization are carried out at the same time. After the initializations, the state estimation results are jointly optimized by bundle adjustment. The proposed method retains more mapping information, and correspondingly is more adaptable to the initialization scene. It is found that the initialization map constructed by the proposed method features a comparable accuracy to the one constructed by ORB-SLAM3 in monocular inertial mode. Since the online extrinsic parameter estimation can be realized by the proposed method, it is considered better than ORB-SLAM3 in the aspect of portability. By the experiments performed on the benchmark dataset EuRoC, the effectiveness and robustness of the proposed method are validated.

5.
Environ Sci Technol ; 54(23): 15366-15375, 2020 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-33190494

RESUMEN

This study explored the possibility of incorporating extremophilic algal cultivation into dairy wastewater treatment by characterizing a unique algal strain. Results showed that extremophilic microalgae Chlorella vulgaris CA1 newly isolated from dairy wastewater tolerated a high level of ammonia nitrogen (2.7 g/L), which was over 20 times the ammonia nitrogen that regular Chlorella sp. could tolerate. The isolate was mixotrophically cultured in dairy effluent treated by anaerobic digestion (AD) for recycling nutrients and polishing the wastewater. The highest biomass content of 13.3 g/L and protein content of 43.4% were achieved in the culture in AD effluent. Up to 96% of the total nitrogen and 79% of the total phosphorus were removed from the dairy AD effluent. The ability of the algae to tolerate a high level of ammonia nitrogen suggests the potential for direct nutrient recycling from dairy wastewater while producing algal biomass and high value bioproducts.


Asunto(s)
Chlorella vulgaris , Extremófilos , Microalgas , Amoníaco , Biomasa , Nitrógeno , Nutrientes , Fósforo , Aguas Residuales
6.
Water Sci Technol ; 82(1): 144-156, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32910799

RESUMEN

To accelerate the degradation of substrate, 50% liquid digestate recirculation (LDR) was used in the anaerobic digestion (AD) of corn straw. The effects of recirculation on the enzyme activities and biogas production were investigated by comparing with control reactor (ReactorCK). During the AD process, the fermentation system with 50% LDR was more stable. The average biogas and methane production in ReactorLDR were 7,891 mL·d-1 and 347 mL CH4·g-1 VSadded·d-1 respectively. The total volatile fatty acids (TVFAs) concentration in the two reactors both increased at first and then decreased with time. The LDR made the VFAs accumulation significant, especially propionic acid accumulation in 4 ∼ 16 days. The maximum peak value of cellulase, xylanase, dehydrogenase and coenzyme F420 activities in ReactorLDR were 0.51 mg·g-1·h-1, 0.29 mg·g-1·h-1, 4.88 mL·g-1·h-1 and 6.69 µmol·L-1, respectively, which were higher than that in ReactorCK. With or without recirculation, the concentration of TVFAs was positively correlated with cellulase, xylanase and dehydrogenase activities, while was negatively correlated with coenzyme F420 activity. Besides, a very significant correlation existed between hydrolase and dehydrogenase activities and daily biogas production in ReactorCK. And the peaks of cellulase, xylanase and dehydrogenase activities appeared ahead of the peak of daily biogas production with the LDR.


Asunto(s)
Biocombustibles , Zea mays , Anaerobiosis , Ácidos Grasos Volátiles , Fermentación
7.
Sensors (Basel) ; 17(3)2017 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-28245549

RESUMEN

In order to maintain a relatively high accuracy of navigation performance during global positioning system (GPS) outages, a novel robust least squares support vector machine (LS-SVM)-aided fusion methodology is explored to provide the pseudo-GPS position information for the inertial navigation system (INS). The relationship between the yaw, specific force, velocity, and the position increment is modeled. Rather than share the same weight in the traditional LS-SVM, the proposed algorithm allocates various weights for different data, which makes the system immune to the outliers. Field test data was collected to evaluate the proposed algorithm. The comparison results indicate that the proposed algorithm can effectively provide position corrections for standalone INS during the 300 s GPS outage, which outperforms the traditional LS-SVM method. Historical information is also involved to better represent the vehicle dynamics.

8.
Sensors (Basel) ; 17(9)2017 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-28872602

RESUMEN

Inertial navigation system (INS)/Doppler velocity log (DVL) integration is the most common navigation solution for underwater vehicles. Due to the complex underwater environment, the velocity information provided by DVL always contains some errors. To improve navigation accuracy, zero velocity update (ZUPT) technology is considered, which is an effective algorithm for land vehicles to mitigate the navigation error during the pure INS mode. However, in contrast to ground vehicles, the ZUPT solution cannot be used directly for underwater vehicles because of the existence of the water current. In order to leverage the strengths of the ZUPT method and the INS/DVL solution, an interactive multiple model (IMM)-aided ZUPT methodology for the INS/DVL-integrated underwater navigation system is proposed. Both the INS/DVL and INS/ZUPT models are constructed and operated in parallel, with weights calculated according to their innovations and innovation covariance matrices. Simulations are conducted to evaluate the proposed algorithm. The results indicate that the IMM-aided ZUPT solution outperforms both the INS/DVL solution and the INS/ZUPT solution in the underwater environment, which can properly distinguish between the ZUPT and non-ZUPT conditions. In addition, during DVL outage, the effectiveness of the proposed algorithm is also verified.

9.
J Environ Manage ; 193: 423-429, 2017 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-28237223

RESUMEN

Failure of methane yield is common for anaerobic digestion (AD) of "weak-acid/acid" wastes alone. In order to verify the importance of pH of materials on the process performance and the methane yield, the "weak-base" wastes-poplar wastes (PW) were used as substrate of solid-state AD (SS-AD). The results show that PW could be used for efficient methane yield after NaOH treatment, the total methane yield was 81.1 L/kg volatile solids (VS). PW also could be used for anaerobic co-digestion with high-pH cattle slurry (CM). For the group with NaOH pretreatment, time used for reaching stable state was 2 days earlier than that of the group without NaOH pretreatment. The maximal methane yield of 98.2 L/kg VS was obtained on conditions of 1:1 of PW-to-CM (P/C) ratio and NaOH pretreatment, which was 21.1% (p < 0.05) higher than that of PW. The maximal reductions of total solids (TS), VS, cellulose and hemicellulose were 51.3%, 57.5%, 46.0% and 47.0%, respectively, which were associated with the maximal methane yield. The results indicate that PW could be alone used for efficient SS-AD for methane yield after NaOH treatment.


Asunto(s)
Biocombustibles , Metano , Anaerobiosis , Animales , Bovinos , Celulosa , Populus
10.
Sensors (Basel) ; 15(5): 9827-53, 2015 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-25923932

RESUMEN

Initial alignment is always a key topic and difficult to achieve in an inertial navigation system (INS). In this paper a novel self-initial alignment algorithm is proposed using gravitational apparent motion vectors at three different moments and vector-operation. Simulation and analysis showed that this method easily suffers from the random noise contained in accelerometer measurements which are used to construct apparent motion directly. Aiming to resolve this problem, an online sensor data denoising method based on a Kalman filter is proposed and a novel reconstruction method for apparent motion is designed to avoid the collinearity among vectors participating in the alignment solution. Simulation, turntable tests and vehicle tests indicate that the proposed alignment algorithm can fulfill initial alignment of strapdown INS (SINS) under both static and swinging conditions. The accuracy can either reach or approach the theoretical values determined by sensor precision under static or swinging conditions.

11.
Biotechnol Genet Eng Rev ; : 1-16, 2023 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-37083061

RESUMEN

Colorectal cancer is a type of cancer that affects the colon or rectum, which are part of the digestive system. It usually develops from small growths called polyps that can turn cancerous over time. This study aimed to investigate the effects of Jianpi Yiqi prescription on clinical symptoms, inflammation, oxidative stress, efficacy, and adverse reactions in colorectal cancer (CRC) patients. A total of 84 CRC patients treated at a hospital from January 2020 to December 2021 were randomly divided into two groups: the conventional chemotherapy group and the Jianpi Yiqi prescription group. Patients in the Jianpi Yiqi group received traditional Chinese medicine on top of conventional chemotherapy. Clinical symptoms and plasma biomarkers were analyzed and compared between the two groups. Results showed that there were significant differences between the two groups before therapy. After therapy, the Jianpi Yiqi group had lower TCM symptom scores, inflammatory factor indices, MDA and SOD levels, and incidence of adverse reactions than the conventional group. Moreover, the total effective rate and tumor stability rate of the Jianpi Yiqi group were higher than those of the conventional group. The study concluded that Jianpi Yiqi prescription had better clinical efficacy in treating CRC patients compared to conventional chemotherapy, with fewer adverse reactions and better inhibition of inflammatory factors and oxidative stress. Overall, this study suggests that Jianpi Yiqi prescription could be a promising complementary therapy for CRC patients, but more research is needed to confirm these findings.

12.
Chem Commun (Camb) ; 59(77): 11576-11579, 2023 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-37691517

RESUMEN

A comprehensive study was conducted to investigate the failure mechanism of the lithium metal anode (LMA) in air. Simultaneously, an effective reactivation strategy was developed using halogen regulation. Specifically, iodine treatment converts the passivation layer of the exposed Li into LiI with fast Li+ transport ability, thereby improving the electrochemical performance.

13.
Chem Commun (Camb) ; 58(89): 12463-12466, 2022 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-36264058

RESUMEN

A low-concentration (0.5 M) all-fluorinated electrolyte (LCAFE) was designed to stabilize high-energy-density lithium metal batteries. Introducing fluorinated solvents can control the electrolyte's solvation structure, interfacial chemistry, and physicochemical properties. Therefore, this LCAFE has good wettability, nonflammability, and excellent stability for lithium anodes.

14.
Am J Cancer Res ; 11(11): 5338-5357, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34873464

RESUMEN

Our previous studies indicated that the extract of Yi-Yi-Fu-Zi-Bai-Jiang-San (YYFZBJS) had potent anticancer activities by significantly inhibiting intestinal tumor development in ApcMin/+ mice. However, knowledge regarding the mechanism and effect of YYFZBJS in the prevention of colorectal cancer is limited. In this study, we aim to investigate the preventive effects of YYFZBJS in enterotoxigenic Bacteroides fragilis (ETBF)-colonized mice with azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced tumorigenesis. First, the colonic tissues of the AOM/DSS mouse models were collected for biomedical analysis, and gut microbiota profiling was detected post YYFZBJS treatment using a 16S rRNA gene sequencing. Then, antibiotic solution (Abx) mice were acclimated with AOM/DSS treatment and then fed with ETBF with or without YYFZBJS for three cycles. As expected, the intragastric administration of YYFZBJS in the AOM/DSS mouse model significantly decreased the tumor load, the severity of disease activity index (DAI) scores, and the level of M2 macrophage markers such as CD206, Arg-1 and IL-10. Notably, the reverse of polarized macrophages induced by YYFZBJS could suppress CRC cell proliferation and infiltration, as demonstrated by the decrease of some tumor proliferation-related proteins in a dose-dependent manner. Importantly, ETBF dysbiosis can contribute to colon tumor development by stimulating p-STAT3 mediated M2 macrophages polarization to promote chronic inflammation and adenoma malignant transformation, which YYFZBJS can effectively limit. Altogether, we demonstrate that ETBF dysbiosis may contribute to M2 macrophages-promoted colon carcinogenesis and progression of CRC cells, while YYFZBJS could be a promising protective agent against ETBF-mediated colorectal cancer.

15.
ISA Trans ; 105: 377-386, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32475536

RESUMEN

For underwater Strapdown Inertial Navigation System (SINS)/Doppler Velocity Log (DVL) integration system, there are intervals between DVL's transmitting and receiving epochs, which introduces velocity errors when the attitude dynamic occurs. To accelerate the coarse alignment process for SINS/DVL with attitude dynamics, an improved in-motion coarse alignment solution is proposed. First, the DVL aided in-motion coarse alignment method is explored. Then, a DVL velocity compensation algorithm for coarse alignment is proposed. Simulations and a field test are conducted to evaluate the effectiveness of the proposed algorithm under various trajectories. The results indicate that the proposed coarse alignment solution effectively applies the velocity compensation algorithm to the coarse alignment mission, which shows greater performance than the traditional optimization-based alignment (OBA) method in various trajectories.

16.
ACS Omega ; 5(38): 24780-24789, 2020 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-33015496

RESUMEN

A major challenge in converting lignocellulose to biofuel is overcoming the resistance of the biomass structure. Herein, sequential dilute acid-alkali/aqueous ammonia treatment was evaluated to enhance enzymatic hydrolysis of poplar biomass by removing hemicellulose first and then removing lignin with acid and base, respectively. The results show that glucose release in sequential dilute acid-alkali treatments (61.4-71.4 mg/g) was 7.3-24.8% higher than sequential dilute acid-aqueous ammonia treatments (57.2-61.8 mg/g) and 283.8-346.3% higher than control (16.0 mg/g), respectively. Dilute acid treatment removed most hemicellulose (84.9%) of the biomass, followed by alkaline treatment with 27.5% removal of lignin. Roughness, surface area, and micropore volume of the biomass were crucial for the enzymatic hydrolysis. Furthermore, the ultrastructure changes observed using crystallinity, Fourier transform infrared spectroscopy, thermogravimetric analysis, and pyrolysis gas chromatography/mass spectrometry support the effects of sequential dilute acid-alkali treatment. The results provide an efficient approach to facilitate a better enzymatic hydrolysis of the poplar samples.

17.
Environ Sci Pollut Res Int ; 27(30): 37989-38003, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32617819

RESUMEN

Weak-base pretreatment of wheat straw was investigated for its ability to improve biomethane production. Anaerobic digestion (AD) was performed on wheat straw pretreated with 3%, 5%, or 7% Na2CO3 as a weak base. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) spectra demonstrated disruption of lignocellulosic structures by pretreatment. In the 5% Na2CO3 treatment group, cellulose and hemicellulose were retained effectively, with efficient removal of lignin. The removal rates of cellulose, hemicellulose, and lignin were 27.9%, 20.4%, and 31.0%, respectively, after 5% Na2CO3 pretreatment. The methane content (53.3-77.3%) was improved in the 5% Na2CO3 treatment group, with maximum methane production (307.9 L/kg VS) that was 41.6% higher than that of the untreated sample. Cellulose and hemicelluloses were degraded 59.3% and 56.3% after AD. It took 20 days to reach 80% of the maximum cumulative methane production for the 5% Na2CO3 pretreatment group, which was 4 days faster than the untreated group. These results indicate that 5% Na2CO3 pretreatment improve the lignocellulose structure of wheat straw, allowing better biodegradability of wheat straw in AD for increased biogas production, enhanced methane content, and decreased digestion time.


Asunto(s)
Lignina , Triticum , Anaerobiosis , Biocombustibles/análisis , Celulosa , Metano , Espectroscopía Infrarroja por Transformada de Fourier
18.
Trials ; 21(1): 309, 2020 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-32245480

RESUMEN

BACKGROUND: Comprehensive rehabilitation therapy based on traditional Chinese medicine (TCM) has been widely applied in various cancer treatments in China. Thus far, Chinese herbal medicine (CHM) has been shown effective in reducing the adverse effects of chemotherapy and improving the quality of life (QoL) during chemotherapy. The purpose of the present study is to compare the effects of CHM plus Liu Zi Jue (LZJ) exercises with CHM plus rehabilitation education and with placebo plus rehabilitation education in patients who have undergone complete resection for nonsmall-cell lung cancer (NSCLC) followed by postoperative adjuvant chemotherapy. METHODS AND DESIGN: A multicenter, randomized clinical trial will be performed with 354 stage Ib-IIIa NSCLC patients in five centers in China. Patients satisfying the inclusion criteria will be randomly divided into three groups according to a 1:1:1 ratio: intervention group A (IGA), intervention group B (IGB), and control group (CG). Each group will receive adjuvant platinum-based doublet chemotherapy for a total of four cycles. IGA participants will receive chemotherapy combined with CHM and LZJ exercises, IGB participants will receive chemotherapy combined with CHM and rehabilitation education, and CG participants will receive chemotherapy combined with placebo and rehabilitation education. The herbal treatment patients will be given granules daily and LZJ exercises will be performed four times per week during chemotherapy. The primary outcome is QoL, which will be assessed with the European Organization for Research and Treatment of Cancer (EORTC)-QLQ-C43 scale in each cycle. The secondary outcomes include the 2-year disease-free survival rate, disease-free survival, TCM symptoms, tumor markers, safety, and adverse events. After treatment, the patients will be followed up every 3 months within 2 years and every 6 months after 2 years until disease recurrence and/or metastasis. DISCUSSION: Our previous study reported that CHM in combination with chemotherapy could lower the overall incidence of adverse events but increased digestive and gastrointestinal side effects compared with chemotherapy alone in postoperative NSCLC patients. This study will lay a foundation for the effectiveness of chemotherapy with or without a comprehensive rehabilitation program for QoL in patients with postoperative NSCLC. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03372694. Retrospectively registered on 17 December 2018.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/rehabilitación , Medicamentos Herbarios Chinos/uso terapéutico , Terapia por Ejercicio/educación , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/rehabilitación , Antineoplásicos Fitogénicos/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica , Biomarcadores de Tumor , Quimioterapia Adyuvante , China , Ensayos Clínicos Fase III como Asunto , Supervivencia sin Enfermedad , Humanos , Estudios Multicéntricos como Asunto , Periodo Posoperatorio , Calidad de Vida , Ensayos Clínicos Controlados Aleatorios como Asunto
19.
Artículo en Inglés | MEDLINE | ID: mdl-31242650

RESUMEN

Poultry manure is the main source of agricultural and rural non-point source pollution, and its effective disposal through anaerobic digestion (AD) is of great significance; meanwhile, the high nitrogen content of chicken manure makes it a typical feedstock for anaerobic digestion. The performance of chicken-manure-based AD at gradient organic loading rates (OLRs) in a continuous stirred tank reactor (CSTR) was investigated herein. The whole AD process was divided into five stages according to different OLRs, and it lasted for 150 days. The results showed that the biogas yield increased with increasing OLR, which was based on the volatile solids (VS), before reaching up to 11.5 g VS/(L·d), while the methane content was kept relatively stable and maintained at approximately 60%. However, when the VS was further increased to 11.5 g VS/(L·d), the total ammonia nitrogen (TAN), pH, and alkalinity (CaCO3) rose to 2560 mg·L-1, 8.2, and 15,000 mg·L-1, respectively, while the volumetric biogas production rate (VBPR), methane content, and VS removal efficiency decreased to 0.30 L·(L·d)-1, 45%, and 40%, respectively. Therefore, the AD performance immediately deteriorated and ammonia inhibition occurred. Further analysis demonstrated that the microbial biomass yield and concentrations dropped dramatically in this period. These results indicated that the AD stayed steady when the OLR was lower than 11.5 g VS/(L·d); this also provides valuable information for improving the efficiency and stability of AD of a nitrogen-rich substrate.


Asunto(s)
Reactores Biológicos , Estiércol , Agricultura , Amoníaco/análisis , Anaerobiosis , Animales , Biocombustibles/análisis , Pollos , Metano/análisis , Nitrógeno/análisis
20.
Rev Sci Instrum ; 90(8): 085001, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31472661

RESUMEN

The angle misalignment error of a USBL (Ultrashort Baseline) acoustic array is one of the major error sources of the strapdown inertial navigation system/USBL positioning system, which will directly affect the positioning accuracy of the USBL positioning system. For the traditional calibration method cannot accurately estimate the angle misalignment error due to its strict trajectory requirements in the field experiment and the high-precision layout of the transceiver array elements, a new method for estimating the angle misalignment error of a USBL acoustic array based on single transponder and dual-vector reconstruction is studied in this paper. The precondition of USBL misalignment calibration is to locate the underwater transponder accurately. In this paper, the single transponder segmentation iterative long baseline method is used to locate the underwater target transponder. The dual-vector reconstruction method is studied to control the estimation accuracy of USBL misalignment error calibration based on the traditional single transponder method, which provides a theoretical basis for the determination of the iteration times to the USBL angle misalignment error estimation module. The underwater experiment results show that the positioning error could be reduced to less than 1 m after the angle misalignment error compensation. The underwater transponder positioning and the angle misalignment error estimation of USBL could be accomplished in a circle sailing. It is a new method with good performance of high estimation accuracy, simple operation, and easy realization.

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