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23 May 2024

Numerical Study on Pyrolysis Characteristics of Oil-Based Drilling Cuttings in a Two-Layer Screw-Driving Spiral Heat Exchanger

Oil-based drilling cuttings is a pollutive nearly-solid waste produced in oil exploitation that has to be treated for meeting clean production requirement of oil and gas exploration. A two-layer screw-driving spiral heat exchanger was thus proposed for this purpose. To investigate its effectiveness and performance, a 10-component n-decane one-step product proportional distribution chemical model was used to describe oil-based drilling cuttings pyrolysis process, and numerical simulations were carried out of forced convection inside the heat exchanger with a full consideration of pyrolysis and evaporation effects. The influences of rotation speed, screw pitch and cross-sectional shape of spiral tube on pyrolysis, flow, and heat mass transfer characteristics were studied. The results show that the heat absorbed needed for evaporation is much less than that for pyrolysis, and the heat transfer coefficient with consideration of evaporation and pyrolysis is almost two times greater than that without. The pyrolysis rate increases first, and then decreases once the temperature is higher than 838 K due to the coupled effects of temperature and reactant concentration change. The velocity, heat transfer coefficient and conversion ratio of oil-based drilling cuttings all increase with rotation speed, but the conversion ratio increase becomes slower and slower once the rotation speed exceeds 0.2 rad·s−1. The average vorticity and flow resistance of oil-based drilling cuttings both decrease with screw pitch monotonously, while heat transfer coefficient increases first and then decreases because of the opposite effects of centrifugal force and thermal entrance length. Reducing screw pitch can increase conversion ratio, but once screw pitch is smaller than 800 mm, the conversion ratio approaches to a constant. Cross-sectional shape of spiral tube also affects pyrolysis performance, and circular cross-sectional spiral tube seems to be the best.

Keywords: Pyrolysis; Oil-based drilling cuttings; Numerical simulation; Heat and mass transfer


20 May 2024

Advancements in the Bio-degradation of Plastic Waste into Value-added Chemicals: A Recent Perspective

Plastics are an essential component of modern life, but the plastic waste has caused significant environmental pollution and economic losses. The effective solution to these problems is the biodegradation and high-value conversion of plastic waste. After biodegradation, plastic waste is broken into smaller molecules and eventually transformed into innocuous substances like water, carbon dioxide and biomass. High-value conversion enables plastic waste to be converted into products with higher economic value and environmental friendliness. Based on this, we summarize the biodegradation methods of bioplastics and analyze the shortage of these methods. Subsequently, we summarize the progress of converting the degradation products into value-added chemicals, comprehensively analyze the advantages and disadvantages of these bioconversion process, and propose some strategies to address these disadvantages. Finally, we analyze the significance of establishing a microbial-based conversion process that integrates the degradation and the conversion, and propose some potential strategies.

Keywords: Bioplastics; Bioconversion; Biodegradation


17 May 2024


16 May 2024

The Application of Forensic Imaging to Sex Estimation: Focus on Skull and Pelvic Structures

Forensic imaging is recognized as a vital tool in forensic practice mostly reflected by the wide use of post-mortem imaging in death investigations. With the surge of forensic imaging applications and research in recent years, many forensic subdisciplines have adopted this tool as a scientific investigation method, including forensic anthropology. Sex estimation is one of the key assignments in forensic anthropology along with age, ancestry and stature estimation. Traditionally, this assignment is done with non-metric macroscopic examination and metric analysis performed by forensic anthropologists. Today, forensic imaging serves as an auxiliary tool that adds to traditional methods and brings sex estimation to a dynamic era. The purpose of this article is to review forensic imaging methods in forensic anthropology sex estimation with a focus on skull and pelvic structures, aiming to provide insights into the best practices and prospective research directions. 

Keywords: Forensic imaging; Forensic anthropology; Macroscopic examination; Metric analysis; Sex estimation


14 May 2024

Measurement and Structure of Common Prosperity of Urban Residents the Case of Hangzhou, China

Common prosperity is an important feature of the social state that the people of the world aspire to, and an important feature of the Chinese path to modernization. Taking common prosperity as the result of income and assets does not facilitate a full understanding of people’s common prosperity, because common prosperity also includes people’s pursuit of subjective happiness such as happiness and satisfaction. From the perspective of the need for a better life in China, this study constructs a subjective evaluation system of the common prosperity of urban residents, including 5 dimensions and 25 specific indicators. It uses survey data from 460 participants and applies the graded response models to estimate parameters and predict latent variables. We find that 21 indicators are in line with the reasonable range of basic assumptions and parameters. They have a strong ability to distinguish the common prosperity of residents in different regions, but have different functional characteristics. The confirmatory factor analysis shows that the common prosperity index of residents includes four potential factors: income, education, medical care, and old-age care, and ecology, which has a good structural effect. In terms of weight, education, medical care and old-age care are the most important factors influencing common prosperity. Among them, the classification policy of high school entrance examination, the quality and fairness of primary and secondary education, the degree of medical insurance security, and the waste sorting and community security are important aspects of evaluating the Common prosperity of residents. 

Keywords: Subjective cognition of the need for a better life; Common prosperity; Graded Response Models; Measurement; Influence Factors


13 May 2024

Expression of Redox Partner Fusions for Light Driven Cytochrome P450s in the Cyanobacterium Synechocystis sp. PCC. 6803

Cytochrome P450s (P450s) catalyze stereo- and regioselective monooxygenations in the biosynthesis of a wide range of valuable natural compounds. The turnover of P450s requires dedicated electron transfer, usually via a NADPH-dependent reductase. The need for an NADPH-dependent reductase can be circumvented if expressed in photosynthetic organisms by exploiting the photosynthetic reducing power. However, partitioning reducing equivalents towards the P450s needs further optimization. Using our model P450, SbCYP79A1, we have previously shown that by targeting this P450 to the thylakoid membrane, the P450 can obtain its reducing power directly from photosystem I via soluble ferredoxin. Furthermore, we demonstrated using transient expression that fusing a soluble electron carrier to this P450 improves electron partitioning towards the P450 in tobacco. In order to characterize these fusions in a stably transformed organism, we expressed three different redox partner fusions in the cyanobacterium Synechocystis sp. PCC. 6803. We show that biochemical trends observed in the tobacco system are recapitulated in stably transformed Synechocystis sp. PCC. 6803. Overall, the FMN binding domain fusion produces the most oxime per unit of enzyme with and without the presence of the endogenous competing electron sink FNR and NADP+. However, the overall yield of oxime is comparable to the other strains, due to poor steady state levels of the fusion protein. Synechocystis sp. PCC. strains expressing the P450-FMN fusion also display a chlorotic phenotype that can be rescued by switching the nitrogen source from nitrate to ammonia, implying impaired nitrate assimilation. Optimizing electron transport towards the P450 is indeed possible in vivo but also highlights interference with native metabolic processes.

Keywords: Cytochrome P450; Electron transfer; Protein fusions; Photosynthesis; Nitrogen


08 May 2024

Assessing Drone Return-to-Home Landing Accuracy in a Woodland Landscape

While aerial photography continues to play an integral role in forest management, its data acquisition can now be obtained through an unmanned aerial vehicle (UAV), commonly referred as a drone, instead of conventional manned aircraft. With its feasibility, a drone can be programed to take off, fly over an area following predefined paths and take images, then return to the home spot automatically. When flying over forests, it requires that there is an open space for a vertical takeoff drone to take off vertically and return safely. Hence, the automatic return-to-home feature on the drone is crucial when operating in a woodland landscape. In this project, we assessed the return-to-home landing accuracy based on a permanently marked launch pad nested in a wooded area on the campus of Stephen F. Austin State University in Nacogdoches, Texas. We compared four models of the DJI drone line, with each flown 30 missions over multiple days under different weather conditions. When each drone returned to the home launch spot and landed, the distance and direction from the launch spot to the landing position was measured. Results showed that both the Phantom 4 Advanced and the Spark had superior landing accuracy, whereas the Phantom 3 Advanced was the least accurate trailing behind the Phantom 4 Pro.

Keywords: UAV; Drones; Positional accuracy; Return-to-home


06 May 2024

Assessing Energy Emissions and Environmental Impact of Wool Processing: A Case Study of an Indian Textile Mill

The objective of this study is to investigate and analyze the effect of varying sources of energy inputs and their impact on carbon emissions during wool fiber processing. The method involved industrial visits to the textile wool processing mill and interaction with the manufacturing as well as commercial sourcing teams to gather relevant data.  The results and outcome of this analysis indicate that wool wet processing is responsible for a significant carbon emission of about 0.031 tCO2e/unit of production. Coal as a source of energy has the highest carbon emission 0.066 tCO2e/product, while the use of biomass and Pressurized Natural Gas (PNG) had significantly lower CO2 emissions. Further, this study evaluated the scope 1 and scope 2 category emissions produced at the wool processing stage which accounted for 56303.2 tCO2e and 1817.10 tCO2e respectively. 

Keywords: Biomass; CO2 Emission; Green House gases; Renewable energy; Sustainable processing


30 April 2024

Arrestin beta 1 Regulates Alveolar Progenitor Renewal and Lung Fibrosis

The molecular mechanisms that regulate progressive pulmonary fibrosis remain poorly understood. Type 2 alveolar epithelial cells (AEC2s) function as adult stem cells in the lung. We previously showed that there is a loss of AEC2s and a failure of AEC2 renewal in the lungs of idiopathic pulmonary fibrosis (IPF) patients. We also reported that beta-arrestins are the key regulators of fibroblast invasion, and beta-arrestin 1 and 2 deficient mice exhibit decreased mortality, decreased matrix deposition, and increased lung function in bleomycin-induced lung fibrosis. However, the role of beta-arrestins in AEC2 regeneration is unclear. In this study, we investigated the role and mechanism of Arrestin beta 1 (ARRB1) in AEC2 renewal and in lung fibrosis. We used conventional deletion as well as cell type-specific deletion of ARRB1 in mice and found that Arrb1 deficiency in fibroblasts protects mice from lung fibrosis, and the knockout mice exhibit enhanced AEC2 regeneration in vivo, suggesting a role of fibroblast-derived ARRB1 in AEC2 renewal. We further found that Arrb1-deficient fibroblasts promotes AEC2 renewal in 3D organoid assays. Mechanistically, we found that CCL7 is among the top downregulated cytokines in Arrb1 deficient fibroblasts and CCL7 inhibits AEC2 regeneration in 3D organoid experiments. Therefore, fibroblast ARRB1 mediates AEC2 renewal, possibly by releasing chemokine CCL7, leading to fibrosis in the lung.

Keywords: Lung; Fibrosis; IPF; Arrb1; AEC2; Alveolar stem cell; CCL7; Stem cell


26 April 2024

Exact and Heuristic Approaches to Surveillance Routing with a Minimum Number of Drones

The rising cost and scarcity of human labor pose challenges in security patrolling tasks, such as facility security. Drones offer a promising solution to replace human patrols. This paper proposes two methods for finding the minimum number of drones required for efficient surveillance routing: an ILP-based method and a greedy method. We evaluate these methods through experiments, comparing the minimum number of required drones and algorithm runtime. The findings indicate that the ILP-based method consistently yields the same or a lower number of drones needed for surveillance compared to the greedy method, with a 73.3% success rate in achieving better results. However, the greedy method consistently finishes within one second, whereas the ILP-based method sometimes significantly increases when dealing with 14 more locations. As a case study, we apply the greedy method to identify the minimum drone surveillance route for the Osaka-Ibaraki Campus of Ritsumeikan University.

Keywords: Drones; Arc Routing Problem; ILP; Greedy Method