Jialiang Zhang¹, Shumei He¹, Tongjing Liu^2,*, Tianlu Ni¹, Jian Zhou^2,3, Fang Huang¹

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.5, pp. 931-946, 2021, DOI:10.32604/fdmp.2021.015638 - 05 July 2021

Abstract During the displacement of water plugging with binary flooding in internally heterogeneous reservoirs, it is essential to understand the distributions of remaining oil as well as the oil displacement mechanisms at different stages. In this study, two types of internally heterogeneous systems, i.e., vertical and horizontal wells are investigated experimentally through a microscopic approach. The results show that plugging agent types have a greater impact on oil recovery than well types, and foam injection can enhance oil recovery more effectively than gel injection. Additionally, the injection sequence of plugging agents significantly affects oil displacement efficiency. More >

Lord Amoah^1,2,*, Ampofo Twumasi Kwabena³

Journal of Quantum Computing, Vol.3, No.2, pp. 65-77, 2021, DOI:10.32604/jqc.2021.020734 - 22 June 2021

Abstract Recent contrast enhancement (CE) methods, with a few exceptions, predominantly focus on enhancing gray-scale images. This paper proposes a bihistogram shifting contrast enhancement for color images based on the RGB (red, green, and blue) color model. The proposed method selects the two highest bins and two lowest bins from the image histogram, performs an equalized number of bidirectional histogram shifting repetitions on each RGB channel while embedding secret data into marked images. The proposed method simultaneously performs both right histogram shifting (RHS) and left histogram shifting (LHS) in each histogram shifting repetition to embed and… More >

Jian Yang, Xiaoli Li^*, Hui Wang, Kaiqiang Geng

Journal of Renewable Materials, Vol.9, No.12, pp. 2241-2260, 2021, DOI:10.32604/jrm.2021.015565 - 22 June 2021

Abstract In the present study, in order to investigate the effects of fly ash on the structural evolution and strength damage mechanism of Pisha-sandstone cement soil, unconfined compressive strength tests of Pisha-sandstone cement soil with different fly ash content levels and various ages were carried out. The apparent morphology, microstructures, and chemical compositions of the samples were observed and analyzed using ultra-depth three-dimensional microscopy, scanning electron microscopy, and XRD methods. The results revealed that the unconfined compressive strength levels of Pisha-sandstone cement soil samples displayed increasing trends with the increases in fly ash content and age.… More > Graphic Abstract

Xi Chen^1,2, Ying Li^1,2,*, Hualei Bai^1,2, Liyuan Ma^1,2

Journal of Renewable Materials, Vol.9, No.12, pp. 2189-2208, 2021, DOI:10.32604/jrm.2021.015394 - 22 June 2021

Abstract Recycled concrete powder (RCP) is used more and more in cement-based materials, but its influence on the hydration process is still unclear. Therefore, this paper studied the influence of recycled concrete powder (RCP) on the hydration process of cement and provides a theoretical basis for the hydration mechanism of cement composite materials. The hydration heat method was used to systematically analyze the thermal evolution process of cement paste with or without RCP. Hydration products were identified using X-ray diffraction (XRD) and thermal analysis (TG–DSC). The pore structure change of cement pastes was analyzed by mercury… More > Graphic Abstract

Naphol Yoobanpot^1,*, Prakasit Sokrai², Natt Makul²

Journal of Renewable Materials, Vol.9, No.11, pp. 2033-2049, 2021, DOI:10.32604/jrm.2021.015849 - 04 June 2021

Abstract According to empirical evidence, high levels of energy and considerable amounts of natural resources are used in the production of concrete. Given the context, this study explores self-consolidating concrete (SCC) that includes rice husk ash (RHA) and metal furnace slag (MFS) as an alternative to cement and the natural aggregates in standard SCC mixes. In this study, mixture designs are investigated with 20 wt.% of RHA, 10–30 wt.% of MFS and water-to-powder material ratios of 0.30 and 0.40. Based on the findings regarding the fresh-state, hardened-state, and durability properties of the resulting SCC mixes, it More >

Jadranka Separovic Hanzevacki¹, Marija Brestovac^1,*, Vlatka Reskovic Luksic¹, Blanka Glavas Konja¹, Martina Lovric Bencic¹, Josko Bulum¹, Darko Anic²

Congenital Heart Disease, Vol.16, No.5, pp. 469-475, 2021, DOI:10.32604/CHD.2021.015237 - 03 June 2021

Abstract Patients with complete transposition of the great arteries (TGA) treated by the Senning procedure have a higher risk of developing heart failure due to: a) additional work load of the systemic (morphologic right) ventricle (sRV), b) arrhythmias, mainly caused by surgical implications at the atria as well as c) worsening of systemic tricuspid regurgitation. We present a unique case of a female patient who developed all these complications, who was successfully treated and was able to carry out a twin pregnancy. This breakthrough approach was based on: 1. detecting reversibility potential of myocardial systolic dysfunction… More >

Sandhia Bai¹, A. K. Amirruddin¹, A. K. Pandey^2,*, M. Samykano^1,*, Muhammad Shakeel Ahmad³, Kamal Sharma⁴, V. V. Tyagi⁵

Energy Engineering, Vol.118, No.4, pp. 737-759, 2021, DOI:10.32604/EE.2021.016157 - 31 May 2021

Abstract The global increase in energy demand has resulted in the depletion of non-renewable resources and caused environmental degradation. Consequently, emerging renewable technologies are a potential solution to fulfil energy demand and mitigate the effect of global warming. Low-cost solar energy harvesting technologies are most feasible technologies. Various solar cells technologies have been developed with improved overall performance and conversion efficiency. However, due to low cost and a wide range of applications, dye-sensitized solar cells (DSSCs) have been immensely focused on one of the most promising third-generation solar cells. The highest conversion efficiency of DSSC achieved… More >

Baoyu Ma^1,*, Guansuo Dui², Zhenglin Jia¹, Bo Yang¹, Chunyan Yang¹, Quangui Gao¹, Longhua Qin¹, Ju Ma¹

CMES-Computer Modeling in Engineering & Sciences, Vol.127, No.3, pp. 1059-1067, 2021, DOI:10.32604/cmes.2021.015776 - 24 May 2021

Abstract A simple hydration model is used here by taking the composition of the cement and the initial water: cement ratio (w/c) into account explicitly. Its conceptual basis is a combination of the Avrami equation and Bentz’s model based on simple spatial considerations. In this model, the Avrami equation determines the initial reaction, and Bentz’s model describes the following hydration stage. The model favors engineers for it relies on one experimental parameter and has a reliable approximation in the practice. More >

Yang Wang¹, Hanxi Wang^2,*, Linwei Yang¹, Li Qian¹

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 845-857, 2021, DOI:10.32604/fdmp.2021.015961 - 24 May 2021

Abstract In order to analyze the coupled influence of temperature and humidity on early-age concrete (including cement and copper tailings), a mathematical model is introduced on the basis of the Krstulovic-Dabic hydration reaction kinetic equations. In such a framework, the influence of hydration-released heat and water consumption are also taken into account. The results provided by such a model are verified by means of experiments and related sensor measurements. The research results show that this model can adequately predict the internal temperature and the humidity temporal evolution laws. More >

Lin Zhou^1,*, Qiuyue Zhong¹, Tianyi Wang¹, Siyuan Lu¹, Hongmei Hu²

Computer Systems Science and Engineering, Vol.38, No.3, pp. 279-289, 2021, DOI:10.32604/csse.2021.016524 - 19 May 2021

Abstract Generative adversarial networks (GANs) are paid more attention to dealing with the end-to-end speech enhancement in recent years. Various GAN-based enhancement methods are presented to improve the quality of reconstructed speech. However, the performance of these GAN-based methods is worse than those of masking-based methods. To tackle this problem, we propose speech enhancement method with a residual dense generative adversarial network (RDGAN) contributing to map the log-power spectrum (LPS) of degraded speech to the clean one. In detail, a residual dense block (RDB) architecture is designed to better estimate the LPS of clean speech, which… More >