A new method for evaluating roundness error using polar measurement data, which named as polar mesh searching algorithm (PMSA), has been presented in this paper. The principle of the algorithm was ...that series of polar-coordinate mesh points were collocated around the periphery of the least square circle according to certain rule, the radius of all the measured points were calculated by regarding each mesh point as the ideal center, and the roundness error from minimum circumscribed circle method, maximum inscribed circle method and minimum zone circle method were achieved accurately through comparing these radius. In the paper, the process and steps using the PMSA to solve the roundness error were described in detail and the mathematical formula and program flowchart were given. The simulation and experiment results show that roundness error can be evaluated effectually and accurately by this algorithm.
Based on the Aspen Plus software, MEA-based CO₂ capture system, steam cycle system, CO₂ compression system, AHT (Absorption Heat Transformer) and AHP (Absorption Heat Pump) models are established. ...Effects of the key parameters on the MEA regeneration energy consumption are analyzed. Two different integration ways are proposed. The steam supplied for regeneration of the solvent will be extracted before it is directed to the low-pressure (LP) turbines and the original LP feeding water heater system will be replaced by the new integration subsystem. The main integration processes of CO₂ capture unit with the original power plant mainly includes the following four parts: (1) adding a letdown steam turbine and a heater for the parameter match before the steam is supplied for regeneration process; (2) the recovery of heat from the gas that mainly consists of CO₂ and H₂O at the top part of the stripper; (3) the heat recovery from the CO₂ compression process; (4) the recovery of heat with application of AHT and AHP. The performance of a case of 600 MW coal-fired power plant with 85% CO₂ capture based on MEA system is studied and the system net efficiency only reduces about 6–8 percent points.
An attractive approach for the preparation of spirocyclic benzofuran-furocoumarins has been developed through iodine-catalyzed cascade annulation of 4-hydroxycoumarins with aurones. The reaction ...involves Michael addition, iodination, and intramolecular nucleophilic substitution in a one-step process, and offers an efficient method for easy access to a series of valuable spirocyclic benzofuran-furocoumarins in good yields (up to 99%) with excellent stereoselectivity. Moreover, this unprecedented protocol provides several advantages, including readily available materials, an environmentally benign catalyst, a broad substrate scope, and a simple procedure.
The application potential and environmental benefits of ground source heat pump (GSHP) systems have become the focal points of decarbonization in the building sector. Synchronized and scientific ...analysis of GSHP systems' environmental and economic performance, however, remains lacking. This study analyzes the application prospects of GSHP systems via a life cycle assessment-based life cycle costing method, and considers China's actual status quo. The internal and external annual costs of a GSHP system per square meter are $ 4.05 and $ 1.37, respectively. Electricity generation and steel production are key processes to improve the environmental performance of a GSHP system further. Compared with coal-based heating, a GSHP system can mitigate 65%–95% of the environmental impact and 85% of external costs, except for the metal depletion impact which is 1.5 times higher than that of coal-based heating. In Shandong Province, promoting GSHP systems can substitute up to 69.4% of the district heating area, which implies reductions in fossil depletion, greenhouse gas emissions, human health impact, ecosystem quality impact, and external costs by up to 2.37 × 1010 kg oil eq, 1.08 × 1011 kg CO2 eq, 3.87 × 105 DALY, 1.18 × 103 Species. year, and $ 2.51 × 1010, respectively. In consideration of environmental and economic aspects, a GSHP system can exhibit benefits compared with coal-based heating after 2.34 years of operation. To improve the economic and environmental performance of GSHP systems, a series of recommendations on financial subsidies, renewable energy development, inter-regional power transmission, steel scrap utilization, and hydrogen reduction steelmaking is provided.
•Environmental and economic feasibilities of a ground source heat pump were examined.•Electricity generation and steel production are the main contributors.•More than 65% of environmental impact and 85% of external costs can be mitigated.•A ground source heat pump shows its life cycle benefits after 2.34-years operation.•The application potential in the cities of Dongying, Yantai, and Qingdao is high.
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When no Mo content was present, the major product of octanoic acid conversion was C7. Adding certain Mo particles to the Ni–ZrO2 catalyst could not only improve the octanoic acid ...conversion but was also beneficial to the generation of C8 alkane distinctly. Meanwhile, the selectivity of C8 had an increasing trend with the Mo content till 10wt%, at which the C8 selectivity reached to its maximum of 77.07% with a complete acid conversion. When the Mo content increased to 15wt%, the octanoic acid conversion as well as C8 selectivity decreased sharply. This could be attributed to that an excess of Mo particles would cover the Ni active sites as well as anionic vacancies on the surface of ZrO2 support.
The different product distributions suggested different octanoic acid conversion mechanisms prevailed over the Ni–ZrO2 and Mo/Ni–ZrO2 catalysts.
•We reported the details of octanoic acid HDO over Ni–ZrO2.•Mo as additive improved the acid conversion and selectivity of octane.•H2–TPD and SEM were used to verify the effect of introducing of Mo.•A reasonable reaction mechanism of octanoic acid conversion was proposed.•The optimal acid conversion was 100%, with a maximum octane yield of 77.07%.
In the current paper, Mo doped Ni–ZrO2 catalyst was prepared, which was used for the liquid hydrocarbon from conversion of octanoic acid via hydrodeoxygenation (HDO). The experimental results showed that the reaction product is mainly C8 alkane with a yield of 77.07% when 10Mo/Ni–ZrO2 was used as the catalyst compared with the major product of C7 alkane over Ni–ZrO2 catalyst with a yield of 69.68%. The introduction of Mo into the Ni–ZrO2 channel generated in Mo/Ni–ZrO2 samples was characterized by nitrogen sorption, TEM, XRD, TPR, and TPD. The results demonstrated that the doping Mo particles to the Ni–ZrO2 catalyst resulted in the transformation of ZrO2 support from cubic form (c-ZrO2) to monoclinic form (m-ZrO2), and the improvement of the hydrogen adsorption capacity and acid property of the catalyst. Thus, the doping of Mo favored the dehydration–hydrogenation reactions of octanol intermediate which in turn facilitated octanoic acid HDO to C8 alkane. Therefore, a novel approach to octanoic acid HDO to C8 alkane is introduced, which provides a basis as well as technical parameters for its further industrialization.
Being the major reason of recurrence and death after surgery, peritoneal metastasis of gastric cancer dooms the prognosis of advanced gastric cancer patients. Regenerating islet-derived family, ...member 4 (REG4) is believed to promote peritoneal metastasis, however, its mechanism is still a moot point at present. In the present study, we show that high expression of REG4 correlates with advanced stage and poor survival prognosis for gastric cancer patients. REG4 overexpression significantly enhances peritoneal metastasis by increasing adhesion ability. Moreover, SP1 is proved to be a transcription factor of REG4 and induce REG4 expression upon TGF-alpha stimulation. Also, G protein-coupled receptor 37 (GPR37) is identified to be in the same complex of REG4, which mediates REG4's signal transduction and promotes peritoneal metastasis of gastric cancer cell. Interestingly, we also discover a positive feedback loop triggered by REG4, amplifying itself through EGFR transactivation, consisting of GPR37, ADAM17, TGF-alpha, EGFR, SP1 and REG4. In conclusion, REG4 promotes peritoneal metastasis of gastric cancer through GPR37 and triggers a positive feedback loop.
In this paper, SO42−/Al2O3-SiO2 (SAS) was prepared and used for the esterification of octanoic acid with methanol. The effect of introduction of SiO2 was characterized by nitrogen sorption, ICP-AES, ...XRD, NH3-TPD, TG, FTIR and FTIR-pyridine adsorption. The results demonstrated that the doping of SiO2 resulted in the increase of BET surface areas and amount of surface sulfur species which led to an increase of acid sites especially Brönsted acid sites, which consequently boosted the catalytic esterification activity. In addition, the introduction of SiO2 can also increase the thermal stability of SO42− and its interaction with Al2O3 support which resulted in the alleviation of catalyst deactivation.
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•We reported a new solid acid of SO42−/Al2O3-SiO2.•SiO2 as additive improved the acid conversion and methyl octanoate yield.•The optimal acid conversion and methyl octanoate yield were 99.11% and 99.07%.•SAS-5 could be recycled for nine times with considerable esterification activity.
Recently, the catalytic upgrading of bio-oil to renewable diesel has been attracting more and more attention. In the current paper, carbon nanotube (CNT)-supported nickel catalysts, namely, 5% ...Ni/CNTs, were prepared for liquid hydrocarbon production through the deoxygenation of palmitic acid, the model compound of bio-oil under a mild condition of 240 °C reaction temperature and 2 MPa H2 pressure. The experimental results revealed that the main reaction product was pentadecane (yield of 89.64%) at an optimum palmitic acid conversion of 97.25% via the hydrodecarbonylation (HDC) process. The deoxygenation mechanism for palmitic acid conversion was also investigated. This study provides technical parameters and a theoretical basis for further industrialization in the bio-oil upgrading process.
To identify genetic abnormalities in primary pancreatic carcinoma in humans.
Comparative genomic hybridization (CGH) was used to investigate genomic imbalances in 27 cases of pancreatic carcinomas. ...Multiple deletions and gains were observed in all tumor specimens.
Losses affecting chromosomes 9p, 17p, 4q and 6p and gains involving 8q, 7q, 3q and 1q were commonly observed.
There are multiple regions of chromosomes with changes copy number in pancreatic carcinoma. The altered chromosomal regions may contain several candidate genes which are involved in the development and progress of pancreatic carcinogenesis.
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