Contact analysis of heavy-duty apron feeder with clearance

The problem of clearance contact between the bearing plate and the supporting guide rail is studied when the heavy‐duty Apron Feeder is subjected to impact load. Based on the energy method, the impact force of the falling ore was calculated, and the nonlinear contact finite element analysis of the structure with clearance was performed using ANSYS Workbench. The results show that at the first moment of contact, the initial contact shape is an approximately linear contact, and then a deformation occurs near the contact line, which quickly evolves from a linear contact to a surface contact. The contact stress distribution is diffused outward along the initial contact boundary and gradually decreases, and the stress concentration occurs at the contact boundary. When the distance is different, the shape of the contact area is similar, but when the distance is large, the contact area is small and the stress distribution is more concentrated. The nonlinear contact calculation of the skirt feeder reveals the instantaneous contact process of the plate rail under the impact force and determines the influence of the distance size on the contact properties, which provides a theoretical basis for the selection of the distance value

Cytotoxic Peptide Conjugates: Anticancer Therapeutic Strategies

ABSTRACT Traditional chemotherapeutic agents exhibit potent anticancer efficacy. However, in clinical applications, they also exhibit severely toxic side effects, and result in multidrug resistance (MDR) of cancer cells. So, receptor-targeted therapy is catching more attention of scientists from both academic and industry and recently is coming to the central stage of drug development. Certain peptides, due to their advantages like, easy synthesis and low cost, less or no immunogenicity, stability and high affinity, have been used as drug delivery vehicles. For example, cell-targeting peptides and cell-penetrating peptides (CPPs) in conjugation with cytotoxic agents have elicited remarkable effects. Luteinizing hormone-releasing hormone, somatostatin, and bombesin/gastrinreleasing peptide are the cell-targeting peptides that interact with their cognate surface receptors aberrantly expressed in many cancer cells, so these hormone peptides can be incorporated into cytotoxic agents for cell-specific targeting in cancer chemotherapy. Due to their cell-penetrating ability, CPPs also serve as cytotoxic drug delivery vehicles to carry drugs across the plasma membrane and overcome MDR of cancer cells. Cytotoxic agents linked to cell-targeting peptides and CPPs have been considered as an effective and reliable method in cancer chemotherapy. In this review, we address the applications of these peptides as drug delivery vehicles in targeted anticancer drug development

Overexpression of long non-coding RNA NORAD promotes invasion and migration in malignant melanoma via regulating the MIR-205-EGLN2 pathway.

Growing evidence suggests that long non-coding RNAs NORAD and miR-205 play a significant role in regulating cancer progression and metastasis. In this study, high expression of NORAD was firstly observed in melanoma tissues and human malignant melanoma cell lines, our aim was to study the interaction of them in the process of invasion and migration of malignant melanoma cells. NORAD, miR-205, and EGLN2 mRNA level in MM cells was detected by qRT-PCR. In situ hybridization (ISH) was performed to detect NORAD expression in MM tissues specimens. Effects of NORAD and miR-205 on Prolyl hydroxylase 2 (EGLN2) expression was explored by western blot in MM cells line. Dual-luciferase reporter assay was performed to verify the interaction relationship between NORAD and miR-205, as well as, miR-205 and EGLN2. Transwell assay was conducted to explore the effects of NORAD and miR-205 in vitro. Xenografts in nude mice experiment were used to confirm the role of NORAD and miR-205 in vivo. In vitro, NORAD knockdown significantly inhibited migration and invasion of malignant melanoma cells and elevated the expression of miR-205, there was an interaction between miR-205 and NORAD in the RNA-induced silencing complex. Upregulation of miR-205 induced significant inhibition of migratory and invasive ability compared with the scrambled control. However, downregulating NORAD largely reversed this effect. Furthermore, the regulatory effects of miR-205 on EGLN2 levels and the induction of endoplasmic reticulum stress were reversed by NORAD. In vivo, deletion of miR-205 induced tumor growth in nude mice. NORAD may play critical roles in tumorigenesis and progression of malignant melanoma by regulating of the miR-205-EGLN2 pathway, and may serve as a new therapeutic target

CO2 emissions from karst cascade hydropower reservoirs: mechanisms and reservoir effect

Carbon dioxide (CO2) emissions from aquatic surface to the atmosphere has been recognized as a significant factor contributing to the global carbon budget and environmental change. The influence of river damming on the CO2 emissions from reservoirs remains poorly constrained. This is hypothetically due to the change of hydraulic retention time (HRT) and thermal stratification intensity of reservoirs (related to the normal water level, NWL). To test this hypothesis, we quantified CO2 fluxes and related parameters in eight karst reservoirs on the Wujiang River, Southwest China. Our results showed that there was a significant difference in the values of pCO2 (mean = 3205.7 μatm, SD = 2183.4 μatm) and δ13CCO2 (mean = −18.9‰, SD = 1.6‰) in the cascade reservoirs, suggesting that multiple processes regulate CO2 production. Moreover, the calculated CO2 fluxes showed obvious spatiotemporal variations, ranging from −9.0 to 2269.3 mmol m−2 d−1, with an average of 260.1 mmol m−2 d−1. Interestingly, the CO2 flux and δ13CCO2 from reservoirs of this study and other reservoirs around the world had an exponential function with the reservoir effect index (Ri, HRT/NWL), suggesting the viability of our hypothesis on reservoir CO2 emission. This empirical function will help to estimate CO2 emissions from global reservoirs and provide theoretical support for reservoir regulation to mitigate carbon emission

Chemical Agglomeration to Enhance Blast Furnace Dust Capture Efficiency in Wet Electrostatic Precipitators

Wet electrostatic precipitators (WESPs) are increasingly used in iron and steel plants and coal-fired power plants due to their higher efficiency at capturing fine particles than conventional dry-type precipitators. In order to achieve ultra-pure purification of dust in steel plant gas, we propose an improved method that involves adding a chemical coagulant and a surfactant to a WESP. The effects of the type and concentration of chemical coagulant and surfactant on the agglomeration effect and dust removal efficiency of blast furnace dust were investigated. The results show that the addition of a chemical coagulant could promote the agglomeration of blast furnace dust particles, and the D50 of dust particles increased from 5.8 to 15.0 μm after the addition of xanthan gum (XTG). The best increase in the blast furnace’s dust particle removal occurred at a concentration of 10 mg/L of XTG, and the dust removal efficiency reached 97.59%. The surfactant dodecyl trimethyl ammonium chloride (DTAC) improved the dust removal efficiency of blast furnace dust when added alone. The dust removal efficiency reached 97.82% when 10 mg/L of XTG and 9 mg/L of DTAC were added synergistically. The addition of a chemical coagulant and surfactant promoted the agglomeration of blast furnace dust and enhanced the dust capture effect of a WESP. We thus demonstrated that we can improve the efficiency of WESP in the future via chemical coagulation. The authors will further study the effect of multi-factor synergistic coupling on the chemical coagulation method in WESPs

Experimental Study on Humidification Coagulation and Removal of Fine Particles Using an Electrostatic Precipitator

A wet electrostatic precipitator (WESP) has much higher capture rate for fine particulate matter, PM2.5, than a traditional dry type electrostatic precipitator does. In order to make full use of existing dust removal equipment and reduce the emissions of smoke and dust to zero, a combination of chemical coagulation and humidification coagulation is proposed using a WESP. The results show that the addition of chemical coagulant can promote the coagulation of coal-fired dust particles. After the addition of pectin (PG), the median diameter of dust particles increases from 28.19 μm to 45.28 μm. Water vapor humidification can promote the coagulation of dust particles. When the water vapor injection rate increases from 0 kg/h to 3.2 kg/h, the median diameter of dust particles increases from 28.19 μm to 36.45 μm. The synergistic effect of the coagulant and water vapor can enhance the chemical coagulation effect; when 1.0 × 10−2 g/L PG and 3.2 kg/h water vapor synergize, the collection efficiency reaches 98.17%, and when 1.0 × 10−2 g/L polyacrylamide (PAM) and 3.2 kg/h water vapor synergize, the collection efficiency reaches 96.68%. Both chemical coagulation and water vapor humidification can promote the condensation of coal dust, which is beneficial to improve the efficient capture of fine particles using WESP

Calculation of GTFP and its influencing factors in Guangdong-Hong Kong-Macao Greater Bay Area

Under the background of dual carbon target, the manufacturing industry in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) is facing the pressure of green transformation. This paper takes this as the research basis, collects the production panel data of the manufacturing industry in the GBA in the past decade, calculates the green development level of the GBA and finds out the important influencing factors, so as to provide theoretical suggestions for the green production and green development of the manufacturing industry in the GBA

Mountainous SAR Image Registration Using Image Simulation and an L₂E Robust Estimator

Synthetic Aperture Radar (SAR) is one of the most widely utilized methods to extract elevation information and identify large-scale deformations in mountainous areas. Homologous points in stereo SAR image pairs are difficult to identify due to complex geometric and radiometric distortions. In this paper, a new approach for mountainous area images is suggested. Firstly, a simulated SAR image and a look-up table based on DEM data are generated by a range-Doppler model and an empirical formula. Then, a point matching RPM-L2E algorithm is used to match images obtained by the simulation and in real-time to indirectly obtain the feature points of the real SAR images. Finally, the accurate registration of mountainous areas in the SAR images is achieved by a polynomial transform. Experimental verification is performed by using the data of mountainous SAR images from the same sensor and different sensors. When the registration accuracy of the method is compared with that of two state-of-the-art image registration algorithms, better outcomes are experimentally shown. The suggested approach can effectively solve the registration problem of SAR images of mountainous areas, and can overcome the disadvantages of poor adaptability and low accuracy of traditional SAR image registration methods for mountainous areas

DC Flashover Performance of Various Types of Ice-Covered Insulator Strings under Low Air Pressure

In this study, icing flashover performance tests of typical DC porcelain, glass, and composite insulators are systematically carried out in a multifunction artificial climate chamber. The DC icing flashover voltages of seven typical insulators under various conditions of icing thickness, pollution severity before icing, string length, and atmospheric pressure are obtained. The relationships between icing thickness, salt deposit density as well as atmospheric pressure and the 50% icing flashover voltage are analyzed, and the formulas are obtained by regression method. In addition, the DC icing flashover voltage correction method of typical porcelain, glass, and composite insulator in the coexisting condition of high altitude, contamination, and icing is proposed