CO2-enhanced catalytic processing of oil shale

Oil shale is a complex mixture consisting of organic matters, mineral matrix and small amount of bound and unbound water. The thermal decomposition of organic substance generates oil and gaseous products. Operating conditions significantly influence the product yield. N2 pyrolysis and CO2-enhanced pyrolysis of small batch of fine oil shale and oil shale/shale ash blends provided different characteristics in both reactions and pyrolyzed products. Co processing of oil shale and agricultural wastes were also investigated in this thesis. First of all, characterization of oil shale, shale ash and agricultural wastes were conducted in order to understand the nature of samples by multiple characterization techniques. Four types of oil shale and shale ash from various regions were used in this study. The kinetic study was carried out for both N2 pyrolysis and CO2-enhanced pyrolysis with four different mathematical models, including Kissinger method, FWO method, KAS method and Coats-Redfern method. Thermal decomposition properties of oil shale and agricultural wastes were studied based on TG and DTG curves results. Activation energy values produced by Coats-Redfern method were compared in pyrolysis reactions in different samples. Alkali index calculated from XRF results was used to identify different catalytic behaviors of shale II ash. In N2 pyrolysis process, gaseous products and shale oil were analyzed by gas chromatography and gas chromatography-mass spectrometry. Peak temperature was found an apparent decrease (10-30︒C) in oil shale/shale ash blends N2 pyrolysis tests compared with oil shale in N2 pyrolysis. Activation energy values of oil shale/shale ash blends also reduced significantly, by around 30 kJmol-1 compared with individual oil shale in N2 pyrolysis. Product yield and shale oil yield were enhanced up to 36% by shale ash catalytic effects. Syngas concentration was also increased up to 14.80% under this circumstance. In CO2-enhanced pyrolysis tests, oil shale with higher ash content showed lower reactivity in the reactions, especially in initial and final stages. Compared with N2 pyrolysis tests, CO2 enhanced pyrolysis tests results exhibited higher yield and selectivity in syngas, from 14.80% to 20.30%. Though shale oil yield was decreased, gas yield was apparently increased. The main purpose of utilizing agricultural wastes and oil shale in pyrolysis process is turning waste materials into high-added value products. In the co-pyrolysis process, different blending ratio had various effects on thermal decomposition process. Residual mass content increase with increasing oil shale content. This trend was due to the high volatile content and low fixed carbon content in agricultural wastes compared to oil shale. The agricultural wastes contained III cellulose, hemicellulose and lignin, which constituted the macromolecular structure of woody materials. The highest activation energy was observed in the final period of pyrolysis with blending ratio of 7:3 (agricultural wastes to oil shale). Activation energy was considered as initiative energy barrier in the reaction. This implied that lower activation energy could promote co-pyrolysis process. Shale ash can be used as potential catalysts in N2 pyrolysis and CO2 enhanced pyrolysis because of thermal stability and splendid behavior. Co-processing of oil shale and other organic-rich materials is an efficient approach for the conversion of oil shale into high-value products

Convergence properties of a family of inexact Levenberg-Marquardt methods

We present a family of inexact Levenberg-Marquardt (LM) methods for the nonlinear equations which takes more general LM parameters and perturbation vectors. We derive an explicit formula of the convergence order of these inexact LM methods under the H$\mathrm{\ddot{o}}$derian local error bound condition and the H$\mathrm{\ddot{o}}$derian continuity of the Jacobian. Moreover, we develop a family of inexact LM methods with a nonmonotone line search and prove that it is globally convergent. Numerical results for solving the linear complementarity problem are reported

SRCD: Semantic Reasoning with Compound Domains for Single-Domain Generalized Object Detection

This paper provides a novel framework for single-domain generalized object detection (i.e., Single-DGOD), where we are interested in learning and maintaining the semantic structures of self-augmented compound cross-domain samples to enhance the model's generalization ability. Different from DGOD trained on multiple source domains, Single-DGOD is far more challenging to generalize well to multiple target domains with only one single source domain. Existing methods mostly adopt a similar treatment from DGOD to learn domain-invariant features by decoupling or compressing the semantic space. However, there may have two potential limitations: 1) pseudo attribute-label correlation, due to extremely scarce single-domain data; and 2) the semantic structural information is usually ignored, i.e., we found the affinities of instance-level semantic relations in samples are crucial to model generalization. In this paper, we introduce Semantic Reasoning with Compound Domains (SRCD) for Single-DGOD. Specifically, our SRCD contains two main components, namely, the texture-based self-augmentation (TBSA) module, and the local-global semantic reasoning (LGSR) module. TBSA aims to eliminate the effects of irrelevant attributes associated with labels, such as light, shadow, color, etc., at the image level by a light-yet-efficient self-augmentation. Moreover, LGSR is used to further model the semantic relationships on instance features to uncover and maintain the intrinsic semantic structures. Extensive experiments on multiple benchmarks demonstrate the effectiveness of the proposed SRCD.Comment: 10 pages, 5 figure

Investigation of the Mathematical Relationship between the Aortic Valve and Aortic Root: Implications for Precise Guidance in Aortic Valve Repair

Background: The study was aimed at investigating the mathematical relationship between the aortic valve and aortic root through CTA imaging-based reconstruction. Methods: We selected 121 healthy participants and analyzed the measurements of aortic root dimensions, including the sinotubular junction (SJT), ventriculo-arterial junction (VAJ), maximum sinus diameter (SD), sinus height (SH), effective height (eH) and coaptation height (cH). We also reconstructed 3-D aortic valve cusps using CTA imaging to calculate the aortic cusp surface areas. Data were collected to analyze the ratios and the correlation between aortic valve and aortic root dimensions. Results: Among healthy participants, the STJ was approximately 10% larger than the VAJ, and the SD was 1.375 times larger than the VAJ. The average eH and cH were 8.94 mm and 3.62 mm, respectively. The aortic cusp surface areas were larger in men than women. Regardless of sex, the non-coronary cusp was found to be largest, and was followed by the right coronary cusp and the left coronary cusp. Although the aortic root dimensions were also significantly larger in in men than women, the STJ to VAJ, SD to VAJ, and SH to VAJ ratios did not significantly differ by sex. The mathematical relationship between the aortic cusp surface areas and VAJ orifice area was calculated as aortic cusp surface areas Conclusions: The aortic root has specific geometric ratios. The mathematical relationship between the aortic valve and aortic root might be used to guide aortic valve repair

Effects of microwave-enhanced pretreatment on oil shale milling performance

Oil shale, as an unconventional fossil fuel, exhibits unique properties compared with coal and other petroleum. Due to the nature of sedimentary rock, large amounts of inorganic mineral impurities in rock matrix reduce the grade of oil shale, whilst increase the grinding resistance. This investigation presents the effects of microwave-enhanced pretreatment on the nature of oil shale and compared with conventional preheating process. Two Chinese oil shale from Fushun and Xingsheng Deposits were grounded and sieved into a size fraction (1-1.18mm) and were cut into eighteen cube-shaped specimens respectively. The prepared samples were processed accordingly to investigate how the grindability changed, in comparison to that of raw samples, and how the fundamental chemical properties of oil shale were altered after pretreatment. Quantitive data were used to assess the effects of different pretreatment methods on oil shale milling performance in a lab-scale pulverizer along with the impacts on moisture content, chemical properties. The uniaxial compressive strength (σmax) of Fushun oil shale was reduced 63.1% and the breakage rate increased 44.9% by short exposure to microwave irradiation. In conclusion, microwave-enhanced pretreatment presents significant improvement in oil shale milling performance compared to conventional preheating process in terms of breakage rate (Si) and uniaxial compressive strength (σmax) which showed negligible alterations. © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of ICAE2018 - The 10th International Conference on Applied Energy

CO2 gasification and pyrolysis reactivity evaluation of oil shale

This research focuses on the non-isothermal CO2 gasification and pyrolysis reactivity via thermogravimetric analysis. It was found that CO2 decreased activation energy of all four types of oil shale (Fushun, Jinzhou, Wulin, Xingsheng). Activation energy of XS oil shale was highly reduced from 59.86 kJ/mol to 9.48 kJ/mol. Reactivity index results showed that WL and XS oil shales were observed to be more dependent on CO2 atmosphere. Alkali metal oxide also contributed to thermal decomposition according to thermogravimetric (TG) and differential thermal analysis (DTG) curves during CO2 gasification process. Overall, CO2 atmosphere can be used to improve oil shale decomposition, especially for alkali- rich shales, while providing an efficient and effective means to convert greenhouse gases into useful fuels. © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of ICAE2018 - The 10th International Conference on Applied Energy

The kinetics studies and thermal characterisation of biomass

This work aims to investigate and develop a method to evaluate and predict the combustion behaviour and combustion efficiency of different biomass commonly used in power plants via simple characterisation methods. 11 types of agricultural and industrial wastes were characterised using thermogravimetric analyser to obtain the derivative thermogravimetric (DTG) data and kinetic parameters. For the samples tested, the initiation temperatures were found to be in the range between 224.39 0 C and 260.33 0 C, whilst the local minimum temperatures between 2 peaks were within the range of 360.36 to 382.74 0 C. It was established that there is a clear, direct relationship between the pre-exponential factor and the temperature interval for the first step of combustion. This trend was apparent and recorded for the 2 heating rates tested. © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of ICAE2018 - The 10th International Conference on Applied Energy

Risk Assessment of Etanercept in Mice Chronically Infected With Toxoplasma gondii

Toxoplasma gondii (T. gondii) is a zoonotic parasite that severely harms the health of the host. The cysts of T. gondii can reactivate from bradyzoites to tachyzoites, if the individual develops low or defective immunity, causing lethal toxoplasmosis. The host resists T. gondii infection by mediating Th1-type cellular immunity to generate pro-inflammatory cytokines. Tumor necrosis factor (TNF) is an important pro-inflammatory cytokine, which can induce lysosomal fusion of parasitophorous vacuole (PV) to kill parasites. Etanercept is a soluble TNF receptor fusion protein, which is widely used clinically to cure autoimmune diseases. The effects and specific molecular mechanisms of etanercept treatment on patients co-infected with autoimmune diseases and chronic toxoplasmosis are rarely reported. In our study, a mouse model of chronic infection with T. gondii and murine macrophages RAW264.7 cells infected with T. gondii were employed to investigate the impact of etanercept on the status of chronic infection. The cytokines levels and a series of phenotypic experiments in vivo and in vitro were measured. In the present study, the expression levels of TNF, IL-1β, and IL-6 were decreased and the brain cysts number was increased in mice chronically infected with T. gondii after being treated with etanercept. In vivo experiments confirmed that etanercept caused a decrease in the immune levels of the mice and activated the brain cysts, which would lead to conversion from chronic infection to acute infection, causing severe clinical and pathological symptoms. Murine macrophages RAW264.7 cells were pretreated with etanercept, and then infected with T. gondii. In vitro experiments, the expression levels of cytokines were decreased, indicating that etanercept could also reduce the cells’ immunity and promote the transformation of bradyzoites to tachyzoites, but did not affect the intracellular replication of tachyzoites. In summary, etanercept treatment could activate the conversion of bradyzoites to tachyzoites through reducing host immunity in vivo and in vitro. The results obtained from this study suggest that the use of etanercept in patients co-infected with autoimmune diseases and chronic toxoplasmosis may lead to the risk of activation of chronic infection, resulting in severe acute toxoplasmosis

Managing Excess Lead Iodide with Functionalized Oxo‐Graphene Nanosheets for Stable Perovskite Solar Cells

Stability issues could prevent lead halide perovskite solar cells (PSCs) from commercialization despite it having a comparable power conversion efficiency (PCE) to silicon solar cells. Overcoming drawbacks affecting their long-term stability is gaining incremental importance. Excess lead iodide (PbI2) causes perovskite degradation, although it aids in crystal growth and defect passivation. Herein, we synthesized functionalized oxo-graphene nanosheets (Dec-oxoG NSs) to effectively manage the excess PbI2. Dec-oxoG NSs provide anchoring sites to bind the excess PbI2 and passivate perovskite grain boundaries, thereby reducing charge recombination loss and significantly boosting the extraction of free electrons. The inclusion of Dec-oxoG NSs leads to a PCE of 23.7 % in inverted (p-i-n) PSCs. The devices retain 93.8 % of their initial efficiency after 1,000 hours of tracking at maximum power points under continuous one-sun illumination and exhibit high stability under thermal and ambient conditions

Genome-Wide Histone H3K27 Acetylation Profiling Identified Genes Correlated With Prognosis in Papillary Thyroid Carcinoma

Thyroid carcinoma (TC) is the most common endocrine malignancy, and papillary TC (PTC) is the most frequent subtype of TC, accounting for 85–90% of all the cases. Aberrant histone acetylation contributes to carcinogenesis by inducing the dysregulation of certain cancer-related genes. However, the histone acetylation landscape in PTC remains elusive. Here, we interrogated the epigenomes of PTC and benign thyroid nodule (BTN) tissues by applying H3K27ac chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) along with RNA-sequencing. By comparing the epigenomic features between PTC and BTN, we detected changes in H3K27ac levels at active regulatory regions, identified PTC-specific super-enhancer-associated genes involving immune-response and cancer-related pathways, and uncovered several genes that associated with disease-free survival of PTC. In summary, our data provided a genome-wide landscape of histone modification in PTC and demonstrated the role of enhancers in transcriptional regulations associated with prognosis of PTC