Xiaorui Zhang^1,2,*, Jiali Duan¹, Wei Sun², Tong Xu¹, Sunil Kumar Jha³

CMES-Computer Modeling in Engineering & Sciences, Vol.127, No.1, pp. 117-133, 2021, DOI:10.32604/cmes.2021.012034

Abstract The cutting simulation of soft tissue is important in virtual surgery. It includes three major challenges in computation: Soft tissue simulation, collision detection, and handling, as well as soft tissue models. In order to address the earlier challenges, we propose a virtual cutting system based on the mass-spring model. In this system, MSM is utilized to simulate the soft tissue model. Residual stress is introduced to the model for simulating the shrinking effect of soft tissue in cutting. Second, a cylinder-based collision detection method is used to supervise the collision between surgical tools and soft tissue. Third, we simulate the… More >

Tianyu Liu¹, Chang Wen^1,2,3,*, Wenyu Wang¹, Kai Yan³, Yongjun Xia⁴, Rui Li³, Juan Liu⁴, Yang Zhang¹

Energy Engineering, Vol.118, No.3, pp. 473-485, 2021, DOI:10.32604/EE.2021.014870

Abstract Pretreatment before biomass combustion is significant for its efficient utilization and that combined water washing and carbonization can be efficient. An agricultural processing residues sesame stalk was selected and carried out two pretreatments separately, i.e., water washing-torrefaction (W-T) and torrefaction-water washing (T-W), to explore the effect on the fuel properties, combustion characteristics and particulate matter (PM) emission. The obtained biochar was also combusted under air and oxy50 (CO₂:O₂ = 50:50) conditions for the sake of investigating the effect of pretreatment and combustion atmosphere. The results indicate that, W-T and T-W both not only have great effect on the improvement of… More >

P. Murugan¹, S. Dhanushkodi^2,*, K. Sudhakar^3,4,*, Vincent H. Wilson⁵

Energy Engineering, Vol.118, No.3, pp. 435-446, 2021, DOI:10.32604/EE.2021.013491

Abstract The quality of the drying process depends mainly on the efficient use of thermal energy. Sustainable systems based on solar energy takes a leading role in the drying of agro-products because of low operating cost. However, they are limited in use during off–sun periods. Biomass dryer is one of the simplest ways of drying because of its potential to dry products regardless of time and climate conditions. The other benefit is that crop residues could be used as fuel in these systems. However, the major limitation of the dryer is unequal drying because of poor airflow distribution in the drying… More >

Park Chan-Yeob, Hyun-Ro Jae, Jun-Yong Jang, Song Hyoung-Kyu^*

CMC-Computers, Materials & Continua, Vol.68, No.1, pp. 137-148, 2021, DOI:10.32604/cmc.2021.016108

Abstract Linear precoding methods such as zero-forcing (ZF) are near optimal for downlink massive multi-user multiple input multiple output (MIMO) systems due to their asymptotic channel property. However, as the number of users increases, the computational complexity of obtaining the inverse matrix of the gram matrix increases. For solving the computational complexity problem, this paper proposes an improved Jacobi (JC)-based precoder to improve error performance of the conventional JC in the downlink massive MIMO systems. The conventional JC was studied for solving the high computational complexity of the ZF algorithm and was able to achieve parallel implementation. However, the conventional JC… More >

Ji-Sung Jung¹, Won-Seok Lee¹, Yeong-Rong Lee¹, Jaeho Kim², Hyoung-Kyu Song^1,*

CMC-Computers, Materials & Continua, Vol.67, No.3, pp. 3057-3070, 2021, DOI:10.32604/cmc.2021.015673

Abstract Massive multiple input multiple output (MIMO) has become essential for the increase of capacity as the millimeter-wave (mmWave) communication is considered. Also, hybrid beamforming systems have been studied since full-digital beamforming is impractical due to high cost and power consumption of the radio frequency (RF) chains. This paper proposes a hybrid beamforming scheme to improve the spectral efficiency for multi-user MIMO (MU-MIMO) systems. In a frequency selective fading environment, hybrid beamforming schemes suffer from performance degradation since the analog precoder performs the same precoding for all subcarriers. To mitigate performance degradation, this paper uses the average channel covariance matrix for… More >

Adeeb Salh¹, Lukman Audah^1,*, Qazwan Abdullah¹, Nor Shahida M. Shah², Shipun A. Hamzah¹, Shahilah Nordin³, Nabil Farah²

CMC-Computers, Materials & Continua, Vol.67, No.3, pp. 3189-3214, 2021, DOI:10.32604/cmc.2021.014746

Abstract Energy efficiency (EE) is a critical design when taking into account circuit power consumption (CPC) in fifth-generation cellular networks. These problems arise because of the increasing number of antennas in massive multiple-input multiple-output (MIMO) systems, attributable to inter-cell interference for channel state information. Apart from that, a higher number of radio frequency (RF) chains at the base station and active users consume more power due to the processing activities in digital-to-analogue converters and power amplifiers. Therefore, antenna selection, user selection, optimal transmission power, and pilot reuse power are important aspects in improving energy efficiency in massive MIMO systems. This work… More >

Qinghua Wang¹, Junzheng Yang¹, Wei Luo^2,*

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.1, pp. 215-233, 2021, DOI:10.32604/fdmp.2021.011914

Abstract Well completions are generally used to connect a reservoir to the surface so that fluids can be produced from or injected into it. With these systems, pipe flows are typically established in the horizontal sections of slotted screen completions and inflow control device (ICD) completions; moreover, an annular flow exists in the region between the pipe and the borehole wall. On the basis of the principles of mass and momentum conservation, in the present study, a coupling model considering the variable mass flow of the central tubing, the variable mass flow of the annular tubing and the reservoir seepage is… More >

Hans Christian Correa-Aguado^1,3, Gloria Viviana Cerrillo-Rojas¹, Alejandro Rocha-Uribe², Ruth Elena Soria-Guerra², José Francisco Morales-Domínguez^1,*

Phyton-International Journal of Experimental Botany, Vol.90, No.2, pp. 515-531, 2021, DOI:10.32604/phyton.2021.013619

Abstract The need for renewable energy sources makes microalgae an essential feedstock for biofuels production. The molecular aspects and the response to nitrogen (N)-limited conditions with a phytohormone stimulus in microalgae have been slightly explored. In this work, Scenedesmus obliquus was used as a study model to analyze the effect of benzyl amino purine (BAP) and gibberellic acid (GA) coupled to nitrogen limitation on cell growth, biomass and fatty acids. The selected 10^-5 M BAP increased the biomass by 1.44-fold, and 10^-6 M GA by 1.35-fold. The total lipids also increased by 2.8 and 1.11-fold, respectively. The 10^-5 M BAP and… More >

Meifen Tian^1,#, Bengang Zhang^2,#, Zhigang Wu^1,2,*, Liping Yu^1,*, Lifen Li¹, Xuedong Xi^2,3

Journal of Renewable Materials, Vol.9, No.4, pp. 789-801, 2021, DOI:10.32604/jrm.2021.013844

Abstract Pinus massoniana wood was modified by steam heat-treatment at 160°C, 180°C, 200°C and 220°C respectively and effects of the changes of density, pH, surface wettability and apparent morphology of Pinus massoniana heat-treated wood on its bonding performance were studied in this paper. The results showed that Pinus massoniana wood underwent a series of physical and chemical changes during heat-treatment as the the following: (1) The degradation of hemicellulose and cellulose with low degree of polymerization, degradation and migration of the extract resulting in the decline of density and pH of heat-treated Pinus massoniana wood. (2) Brittle fracture occured on the… More >

Neha Srivastava^1,*, Akshay Shrivastav², Rajeev Singh³, Mohammed Abohashrh⁴, K. R. Srivastava¹, Safia Irfan⁵, Manish Srivastava¹, P. K. Mishra¹, Vijai Kumar Gupta⁶, Vijay Kumar Thakur^6,*

Journal of Renewable Materials, Vol.9, No.4, pp. 615-636, 2021, DOI:10.32604/jrm.2021.014374

Abstract Increased environmental pollution due to the organic wastes over the world is one of the most burning issues. These organic wastes lie under the category of biodegradable waste and can be effectively degraded from their complex compound into simple one by the action of microbes or other living organisms. Moreover, lignocellulosic biomass is a major part of the biodegradable waste and belongs to the group of renewable energy source, which can be very effective for bioenergy production. Biomasses are made up of different compounds such as cellulose, hemicelluloses, lignin and protein. Apart from these components, based on the structural analysis… More >