Browsing by Author "Wang, Hui"
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Item The Arabidopsis RNA Binding Protein with K Homology Motifs, SHINY1, Interacts with the C-terminal Domain Phosphatase-like 1 (CPL1) to Repress Stress-Inducible Gene Expression(2013) Jiang, Jiafu; Wang, Bangshing; Shen, Yun; Wang, Hui; Feng, Qing; Shi, HuazhongThe phosphorylation state of the C-terminal domain (CTD) of the RNA polymerase II plays crucial roles in transcription and mRNA processing. Previous studies showed that the plant CTD phosphatase-like 1 (CPL1) dephosphorylates Ser-5-specific CTD and regulates abiotic stress response in Arabidopsis. Here, we report the identification of a K-homology domain-containing protein named SHINY1 (SHI1) that interacts with CPL1 to modulate gene expression. The shi1 mutant was isolated from a forward genetic screening for mutants showing elevated expression of the luciferase reporter gene driven by a salt-inducible promoter. The shi1 mutant is more sensitive to cold treatment during vegetative growth and insensitive to abscisic acid in seed germination, resembling the phenotypes of shi4 that is allelic to the cpl1 mutant. Both SHI1 and SHI4/CPL1 are nuclear-localized proteins. SHI1 interacts with SHI4/CPL1 in vitro and in vivo. Loss-of-function mutations in shi1 and shi4 resulted in similar changes in the expression of some stress-inducible genes. Moreover, both shi1 and shi4 mutants display higher mRNA capping efficiency and altered polyadenylation site selection for some of the stress-inducible genes, when compared with wild type. We propose that the SHI1-SHI4/CPL1 complex inhibits transcription by preventing mRNA capping and transition from transcription initiation to elongation.Item Fabrication of a tic‐ti matrix composite coating using ultrasonic vibration‐assisted laser directed energy deposition: The effects of ultrasonic vibration and tic content(2021) Li, Yunze (TTU); Zhang, Dongzhe (TTU); Wang, Hui; Cong, Weilong (TTU)Titanium and its alloys exhibit superior properties of high corrosion resistance, an excel-lent strength to weight ratio and outstanding stiffness among other things. However, their relatively low hardness and wear resistance limit their service life in high‐performance applications of structure parts, gears and bearings, for example. The fabrication of a ceramic reinforced titanium matrix composite (TMC) coating could be one of the solutions to enhance the microhardness and wear resistance. Titanium carbide (TiC) is a preferable candidate due to the advantages of self‐lubrication, low cost and a similar density and thermal expansion coefficient with titanium. The fabrication of TiC‐TMC coatings onto titanium using a laser directed energy deposition (LDED) process has been conducted. The problems of TiC aggregation, low bonding quality and the generation of fabrication defects still exist. Considering ultrasonic vibration could generate acoustic steaming and transient cavitation actions in melted materials, which could homogenize the distribution of reinforcement materials and promote the dissolution of TiC into liquid titanium. In this study, for the first time, we investigate the ultrasonic vibration‐assisted LDED of TiC‐TMC coatings. The effects of ultrasonic vibration and reinforcement content on the phase compositions, reinforcement aggregation, bonding quality, fabrication defects and mechanical properties (including microhardness and wear resistance) of LDED deposited TiC‐TMC coatings have been investigated. With the assistance of ultrasonic vibration, the aggregation of TiC was reduced, the porosity was decreased, the defects in the bonding interface were reduced and the mechanical properties including microhardness and wear resistance were increased. However, the excessive TiC content could significantly increase the TiC aggregation and manufacturing defects, resulting in the reduction of the mechanical properties.Item Inter-stage performance and energy characteristics analysis of electric submersible pump based on entropy production theory(2024) Wang, Hui; Yang, Yang; Xi, Bin; Shi, Wei Dong; Wang, Chuan; Ji, Lei Lei; Song, Xiang Yu; He, Zhao Ming (TTU)The electric submersible pump (ESP) is a crucial apparatus utilized for lifting in the oil extraction process. Its lifting capacity is enhanced by the multi-stage tandem structure, but variations in energy characteristics and internal flow across stages are also introduced. In this study, the inter-stage variability of energy characteristics in ESP hydraulic systems is investigated through entropy production (EP) analysis, which incorporates numerical simulations and experimental validation. The EP theory facilitates the quantification of energy loss in each computational subdomain at all ESP stages, establishing a correlation between microscopic flow structure and energy dissipation within the system. Furthermore, the underlying causes of inter-stage variability in ESP hydraulic systems are examined, and the advantages and disadvantages of applying the EP theory in this context are evaluated. Consistent energy characteristics within the ESP, aligned with the distribution of internal flow structure, are provided by the EP theory, as demonstrated by our results. The EP theory also enables the quantitative analysis of internal flow losses and complements existing performance analysis methods to map the internal flow structure to hydraulic losses. Nonetheless, an inconsistency between the energy characterization based on EP theory and the traditional efficiency index when reflecting inter-stage differences is identified. This inconsistency arises from the exclusive focus of the EP theory on flow losses within the flow field, disregarding the quantification of external energy input to the flow field. This study provides a reference for the optimization of EP theory in rotating machinery while deeply investigating the energy dissipation characteristics of multistage hydraulic system, which has certain theoretical and practical significance.Item Rotary ultrasonic surface machining of carbon fiber reinforced plastic composites(2020-08) Wang, Hui; Cong, Weilong; Zhang, Hong-Chao; Du, Dongping; Li, WeiCarbon fiber reinforced plastic (CFRP) composites are widely used in many industries, such as aerospace, automotive, transportation, and robotics, and their applications are remarkably increasing owing to their superior properties, such as high strength-to-weight ratio, high modulus-to-weight ratio, high fatigue resistance, and high dimensional stability. After near-net-shaped molding fabrication processes, CFRP composites still need additional surface machining processes to generate desired functional surface geometries with good surface quality and high dimensional accuracy. Due to the inhomogeneous and anisotropic properties and abrasive properties of carbon fibers, CFRP composites are considered to be difficult-to-machine materials. Many problems are produced in conventional surface machining of CFRP composites, such as low machining efficiency, undesirable defects, workpiece delamination, high surface roughness, high tool wear, and high cutting force. Facing these problems, it is crucial to develop a high-effectiveness, high-efficiency, and high-quality surface machining process to effectively reduce and further solve these problems. It is reported that these problems can be effectively reduced in the hole making of CFRPs using rotary ultrasonic machining with vertical ultrasonic vibration, which is originally developed for the hole making process. Therefore, rotary ultrasonic machining with vertical ultrasonic vibration is extended to the surface machining of CFRP composites. Compared with hole making of CFRPs using rotary ultrasonic machining, rotary ultrasonic surface machining (RUSM) of CFRPs has different tool-workpiece interactions for material removal, which result in different material removal mechanisms, different cutting-force generation mechanisms, and different dominant cutting force components in RUSM processes. Therefore, the newly developed RUSM process of CFRPs needs to be deeply studied to get a fundamental understanding of this process. To achieve these goals, this dissertation aims at discovering the material removal mechanisms, the cutting-force generation mechanisms, and the tool-workpiece interactions in RUSM of CFRPs through the fundamentally experimental and theoretical studies. In this dissertation, a comprehensive literature review on surface machining of composites is firstly conducted to provide the fundamental knowledge on understanding surface machining of composites. Then, RUSM processes with different ultrasonic conditions are proposed and applied to process CFRPs in order to seek the potential solutions to the aforementioned problems so as to improve CFRP machinability, surface machining performance, and machined surface quality of CFRP workpiece. Based on the ultrasonic vibration conditions applied in RUSM processes, the investigations on RUSM processes of CFRPs can be divided into three categories, including RUSM of CFRPs with vertical ultrasonic vibration, RUSM of CFRPs with horizontal ultrasonic vibration, and RUSM of CFRPs with elliptical ultrasonic vibration, being formed from the combination of vertical ultrasonic vibration and horizontal ultrasonic vibration. First of all, RUSM of CFRPs with vertical ultrasonic vibration is experimentally and theoretically studied. The experimental investigations on this topic include the effects of machining variables, effects of workpiece machining orientations, effects of tool variables, effects of tool orientations, and design of experiment on output variables (including cutting forces, torque, surface roughness, and machined surface characteristics). The theoretical studies are conducted through the materials removal mechanisms and the mechanistic model for both cutting force in feeding direction and cutting force in the depth-of-cut direction based on both ductile and brittle facture material removal modes. The results of these investigations show that RUSM of CFRPs with vertical ultrasonic vibration generates lower cutting forces and higher surface roughness than the process without ultrasonic vibration since the up-and-down vertical ultrasonic vibration will generate damages on the machined CFRP surface. It is found that to simultaneously reduce cutting forces and improve the machined surface quality, the applied ultrasonic vibration should be aligned with surface generation direction (namely horizontal feeding direction). In the next place, RUSM of CFRPs with horizontal ultrasonic vibration is explored to achieve this goal, and its machining performance and machined surface quality are evaluated as compared with conventional surface machining without ultrasonic vibration. It is found that RUSM of CFRPs with horizontal ultrasonic vibration produces both reduced cutting forces and reduced surface roughness. Then, the effects of ultrasonic frequency on output variables and the critical ultrasonic frequency for abrasive-grain trajectory overlapping are studied and analyzed to improve the performance of RUSM processes. Furthermore, a mechanistic model on feeding-directional cutting force is built to better understand the tool-workpiece interactions, the cutting-force generation mechanisms, and the material removal mechanisms in RUSM of CFRPs with horizontal ultrasonic vibration. Besides, the vertical and horizontal ultrasonic vibrations can work together to form the elliptical ultrasonic vibration. Finally, RUSM of CFRPs with elliptical ultrasonic vibration is investigated to further improve the machining performance and machined surface quality of RUSM processes. The investigations on this topic include the process-performance evaluation through comparisons between this process and the process with horizontal ultrasonic vibration as well as the conventional surface machining without ultrasonic vibration and a developed feeding-directional cutting force model to study the tool-workpiece interactions and the mechanisms of material removal and cutting-force generation in RUSM of CFRPs with elliptical ultrasonic vibration. In a word, this dissertation discovers the advantages of RUSM of CFRP composites under different ultrasonic vibration conditions (including vertical ultrasonic vibration, horizontal ultrasonic vibration, and elliptical ultrasonic vibration) over conventional surface machining of CFRPs through the comparative experimental investigations in order to determine the feasibilities of different ultrasonic vibration conditions for the assistance of surface machining processes. Moreover, this dissertation generates the fundamental knowledge of tool-workpiece interactions, cutting-force generation mechanisms, and material removal mechanisms in RUSM of CFRPs through experimental and theoretical modeling investigations in order to contribute to building an effective and efficient surface machining process for CFRPs. The generated knowledge will fill in the gap in the literature on surface machining of CFRP composites, benefit the researchers and scientists for future research, and provide guidance to the automotive industry and the aerospace industry.Item The role of HDA6 and FRY2 in gene regulation and abiotic stress response in arabidopsis(2011-05) Wang, Hui; Shi, Huazhong; Paré, Paul W.; Xie, ZhixinGene regulation is a central process in plant response to environmental stresses. Many genes are either up- or down-regulated under stress conditions, which are mediated through signaling pathways starting from perceiving the stress signals. To identify components important for abiotic stress signaling response, a forward genetic approach was employed by using the luciferase reporter gene fused with the SOT12 promoter, an abiotic stress responsive promoter from Arabidopsis. The seeds of the homozygous transgenic line were subjected to EMS mutagenesis and mutants with altered luciferases expression were identified. In this study, two mutants, named 1502 and 1005, were selected for further characterization. Map-based cloning revealed that 1502 mutant harbors a mutation in the gene encoding the Histone Deacetylase 6 (HDA6) and 1005 mutant possesses a mutation in the gene encoding the previously identified protein FRY2. Genetic complementation verified that these mutations are indeed responsible for the mutant phenotypes. Thus, 1502 mutant was renamed to hda6 and 1005 mutant was renamed to fry2. hda6 mutant showed no obvious phenotypes under NaCl or several hormonal treatments. Interestingly, growth of hda6 mutant plants under normal conditions displayed segregated growth phenotypes with no stable segregation ratio, which suggests an epigenetic effect of the hda6 mutation on normal plant growth and development. hda6 mutant exhibited substantially higher luciferase expression than wild type plants with or without NaCl treatment. The increased luciferase expression was attributed to the increased transcript level in hda6 mutant plants. Analysis of 5’capping and polyadenylation site selection of the luciferase mRNA suggested that HDA6 is involved in the regulation of these co-transcription processes, which may partly contribute to the increased transcript level of luciferase gene in hda6 mutant. Yeast two-hybrid screening for HDA6 and FRY2 interacting proteins was attempted and a number of putative interacting proteins were identified. However, protein-protein interaction needs to be further verified in both yeast and plant cells.Item Theoretical and experimental investigations on rotary ultrasonic surface micro-machining of brittle materials(2022) Li, Yunze (TTU); Zhang, Dongzhe (TTU); Wang, Hui; Ye, Gaihua (TTU); He, Rui (TTU); Cong, Weilong (TTU)Many brittle materials, such as single-crystal materials, amorphous materials, and ceramics, are widely used in many industries such as the energy industry, aerospace industry, and biomedical industry. In recent years, there is an increasing demand for high-precision micro-machining of these brittle materials to produce precision functional parts. Traditional ultra-precision micro-machining can lead to workpiece cracking, low machined surface quality, and reduced tool life. To reduce and further solve these problems, a new micro-machining process is needed. As one of the nontraditional machining processes, rotary ultrasonic machining is an effective method to reduce the issues generated by traditional machining processes of brittle materials. Therefore, rotary ultrasonic micro-machining (RUμM) is investigated to conduct the surface micro-machining of brittle materials. Due to the small diameter cutting tool (<500 μm) and high accuracy requirements, the impact of input parameters in the rotary ultrasonic surface micro-machining (RUSμM) process on tool deformation and cutting quality is extremely different from that in rotary ultrasonic surface machining (RUSM) with relatively large diameter cutting tool (∼10 mm). Up till now, there is still no investigation on the effects of ultrasonic vibration (UV) and input variables (such as tool rotation speed and depth of cut) on cutting force and machined surface quality in RUSμM of brittle materials. To fill this knowledge gap, rotary ultrasonic surface micro-machining of the silicon wafer (one of the most versatile brittle materials) was conducted in this study. The effects of ultrasonic vibration, tool rotation speed, and depth of cut on tool trajectory, material removal rate (MRR), cutting force, cutting surface quality, and residual stress were investigated. Results show that the ultrasonic vibration could reduce the cutting force, improve the cutting surface quality, and suppress the residual compressive stress, especially under conditions with high tool rotation speed.Item Two-phase flow investigation of sewage pumps with different tip clearance via computational fluid dynamics and multi-factor ANOVA(2024) Yang, Yang; Wang, Hui; Hu, Qixiang; Ji, Leilei; He, Zhaoming (TTU); Shi, Weidong; Song, Xiangyu; Zhou, LingSewage pumps are widely utilized in various applications, including municipal wastewater treatment plants, industrial processes, and residential sewage systems. These pumps are specifically designed to handle the transportation of mixtures consisting of solid and liquid components, commonly observed as two-phase flow. In this study, semi-open sewage pumps with varying clearance sizes have been examined through adjustment of the geometrical model. Multi-factor analysis of variance is employed to investigate the combined influence of different two-phase flow conditions and tip clearance sizes on the performance of sewage pumps. The results show that the performance of the pump decreases significantly as the clearance size increases. Also, the sensitivity of pump efficiency to variations in tip clearance size is contingent upon the flow rate. Under part-load conditions, both particle concentration and clearance size exhibit a notable effect on efficiency. The two-phase flow will greatly enhance the intensity of the unsteady flow near the inlet and outlet of the semi-open impeller, which is the main reason for the performance degradation of the sewage pump. The findings of this research provide valuable insights for enhancing the hydraulic performance and operational stability of semi-open sewage pumps operating under two-phase flow conditions.