Samples of ground nut hull were converted to biosorbents using microwave assisted method [groundnut hull treated with hydrogen peroxide (HP-GH), groundnut hull treated with distilled water (W-GH) and raw groundnut hul...Samples of ground nut hull were converted to biosorbents using microwave assisted method [groundnut hull treated with hydrogen peroxide (HP-GH), groundnut hull treated with distilled water (W-GH) and raw groundnut hull (R-GH)]. The biosorbents were further characterized using physicochemical procedures (pH dependence, bulk density, surface area, ash content, and volatile matter, moisture content). The results show that HP-GH has pH = 8.9, W-GH pH = 8.4 and R-GH pH = 8.5 which is an indication that all the biosorbents have the appropriate pH values for the uptake of cationic species within aqueous systems. Surface area analysis revealed that HP-GH has the largest surface area (74.20 m<sup>2</sup>·g<sup>-1</sup>) while W-GH and R-GH have surface area values of 29.40 m<sup>2</sup>·g<sup>-1</sup> and 21.40 m<sup>2</sup>·g<sup>-1</sup> respectively. This suggests that modification of raw groundnut hull biomass with hydrogen peroxide possibly instigated delignification of the biomass which resulted in increased surface area for HP-GH. Results from Bulk density analysis also confirm the data obtained from surface area analysis. Accordingly, R-GH displayed the highest bulk density followed by W-GH with HP-GH showing the least bulk density. The variation in pH values among the biomass used in this study may be explained by the variation in their ash content as well because pH and ash content are positively correlated. Hence, HP-GH with a pH = 8.9 has high ash content (117.31%), W-GH with pH = 8.4 has 97.93% ash content and R-GH with pH = 8.5 has 94.26% ash content. Results from moisture content analysis show that HP-GH (99.95%), W-GH (99.97%) and R-GH (99.89%) may necessitate exposure of the biosorbents to moderate heat before use. The results obtained from this study suggest that modification of ground nut hull with either distilled water or Hydrogen peroxide by means of microwave irradiation improves physicochemical properties which may perhaps increase the adsorption capacity of the biomass.展开更多
In order to generate the three-dimensional (3-D) hull surface accurately and smoothly,a mixed method which is made up of non-uniform B-spline together with an iterative procedure was developed.By using the iterative m...In order to generate the three-dimensional (3-D) hull surface accurately and smoothly,a mixed method which is made up of non-uniform B-spline together with an iterative procedure was developed.By using the iterative method the data points on each section curve are calculated and the generalized waterlines and transverse section curves are determined.Then using the non-uniform B-spline expression,the control vertex net of the hull is calculated based on the generalized waterlines and section curves.A ship with tunnel stern was taken as test case.The numerical results prove that the proposed approach for geometry modeling of 3-D ship hull surface is accurate and effective.展开更多
This paper addresses the development and testing of a remotely controlled boat platform with an innovative air-ventilated hull. The application of air cavities on the underside of ship hulls is a promising means for r...This paper addresses the development and testing of a remotely controlled boat platform with an innovative air-ventilated hull. The application of air cavities on the underside of ship hulls is a promising means for reducing hydrodynamic drag and pollutant emissions and increasing marine transportation efficiency. Despite this concept＇s potential, design optimization and high-performance operation of novel air-cavity ships remain a challenging problem. Hull construction and sensor instrumentation of the model-scale air-cavity boat is described in the paper. The modular structure of the hull allows for easy modifications, and an electric propulsion unit enables self-propelled operation. The boat is controlled remotely via a radio transmission system. Results of initial tests are reported, including thrust, speed, and airflow rate in several loading conditions. The constructed platform can be used for optimizing air-cavity systems and testing other innovative hull designs. This system can be also developed into a high-performance unmanned boat.展开更多
Surface reconstruction is a problem in the field of computational geometry that is concerned with recreating a surface from scattered data points sampled from an unknown surface. To date, the primary application of su...Surface reconstruction is a problem in the field of computational geometry that is concerned with recreating a surface from scattered data points sampled from an unknown surface. To date, the primary application of surface reconstruction algorithms has been in computer graphics, where physical models are digitized in three dimensions with laser range scanners or mechanical digitizing probes (Bernardini?et al., 1999?[1]). Surface reconstruction algorithms are used to convert the set of digitized points into a wire frame mesh model, which can be colored, textured, shaded, and placed into a 3D scene (in a movie or television commercial, for example). In this paper, we discuss some computational geometry preliminaries, and then move on to a summary of some different techniques used to address the surface reconstruction problem. The coming sections describe two algorithms: that of Hoppe,?et al. (1992?[2]) and Amenta,?et al. (1998?[3]). Finally, we present other applications of surface reconstruction and a brief comparison for some algorithms in this filed emphasizing on their advantages and disadvantages.展开更多
文摘Samples of ground nut hull were converted to biosorbents using microwave assisted method [groundnut hull treated with hydrogen peroxide (HP-GH), groundnut hull treated with distilled water (W-GH) and raw groundnut hull (R-GH)]. The biosorbents were further characterized using physicochemical procedures (pH dependence, bulk density, surface area, ash content, and volatile matter, moisture content). The results show that HP-GH has pH = 8.9, W-GH pH = 8.4 and R-GH pH = 8.5 which is an indication that all the biosorbents have the appropriate pH values for the uptake of cationic species within aqueous systems. Surface area analysis revealed that HP-GH has the largest surface area (74.20 m<sup>2</sup>·g<sup>-1</sup>) while W-GH and R-GH have surface area values of 29.40 m<sup>2</sup>·g<sup>-1</sup> and 21.40 m<sup>2</sup>·g<sup>-1</sup> respectively. This suggests that modification of raw groundnut hull biomass with hydrogen peroxide possibly instigated delignification of the biomass which resulted in increased surface area for HP-GH. Results from Bulk density analysis also confirm the data obtained from surface area analysis. Accordingly, R-GH displayed the highest bulk density followed by W-GH with HP-GH showing the least bulk density. The variation in pH values among the biomass used in this study may be explained by the variation in their ash content as well because pH and ash content are positively correlated. Hence, HP-GH with a pH = 8.9 has high ash content (117.31%), W-GH with pH = 8.4 has 97.93% ash content and R-GH with pH = 8.5 has 94.26% ash content. Results from moisture content analysis show that HP-GH (99.95%), W-GH (99.97%) and R-GH (99.89%) may necessitate exposure of the biosorbents to moderate heat before use. The results obtained from this study suggest that modification of ground nut hull with either distilled water or Hydrogen peroxide by means of microwave irradiation improves physicochemical properties which may perhaps increase the adsorption capacity of the biomass.
基金The Special Research Fund for the Doctoral Program of Higher Education(No.20050248037)The National Natural Science Foundation of China(No.10572094)
文摘In order to generate the three-dimensional (3-D) hull surface accurately and smoothly,a mixed method which is made up of non-uniform B-spline together with an iterative procedure was developed.By using the iterative method the data points on each section curve are calculated and the generalized waterlines and transverse section curves are determined.Then using the non-uniform B-spline expression,the control vertex net of the hull is calculated based on the generalized waterlines and section curves.A ship with tunnel stern was taken as test case.The numerical results prove that the proposed approach for geometry modeling of 3-D ship hull surface is accurate and effective.
基金Foundation item： Supported by the National Science Foundation （CMMI-1026264 and EEC-1157094）.
文摘This paper addresses the development and testing of a remotely controlled boat platform with an innovative air-ventilated hull. The application of air cavities on the underside of ship hulls is a promising means for reducing hydrodynamic drag and pollutant emissions and increasing marine transportation efficiency. Despite this concept＇s potential, design optimization and high-performance operation of novel air-cavity ships remain a challenging problem. Hull construction and sensor instrumentation of the model-scale air-cavity boat is described in the paper. The modular structure of the hull allows for easy modifications, and an electric propulsion unit enables self-propelled operation. The boat is controlled remotely via a radio transmission system. Results of initial tests are reported, including thrust, speed, and airflow rate in several loading conditions. The constructed platform can be used for optimizing air-cavity systems and testing other innovative hull designs. This system can be also developed into a high-performance unmanned boat.
文摘Surface reconstruction is a problem in the field of computational geometry that is concerned with recreating a surface from scattered data points sampled from an unknown surface. To date, the primary application of surface reconstruction algorithms has been in computer graphics, where physical models are digitized in three dimensions with laser range scanners or mechanical digitizing probes (Bernardini?et al., 1999?[1]). Surface reconstruction algorithms are used to convert the set of digitized points into a wire frame mesh model, which can be colored, textured, shaded, and placed into a 3D scene (in a movie or television commercial, for example). In this paper, we discuss some computational geometry preliminaries, and then move on to a summary of some different techniques used to address the surface reconstruction problem. The coming sections describe two algorithms: that of Hoppe,?et al. (1992?[2]) and Amenta,?et al. (1998?[3]). Finally, we present other applications of surface reconstruction and a brief comparison for some algorithms in this filed emphasizing on their advantages and disadvantages.
