The charge density of cellulose fibers is a key parameter in the papermaking systems,and this is particularly true for the Alkyl Ketene Dimer( AKD) paper sizing.Zeta potential and cationic demand are often used to cha...The charge density of cellulose fibers is a key parameter in the papermaking systems,and this is particularly true for the Alkyl Ketene Dimer( AKD) paper sizing.Zeta potential and cationic demand are often used to characterize these charges.Generally,a similar sizing performance would be obtained when the fibers with similar morphology and charge characteristics are used.However,in a mill trial,it was shown that three bleached birch pulp samples,with similar fiber morphology,and zeta potential,had different AKD sizing behaviors.In this study,the surface charges of these pulp samples,measured using the polyelectrolyte titration methods,were investigated.The results showed that lower sizing efficiency of fibers were due to their lower surface charges.It was concluded that the direct measurement of surface charge of cellulose fibers can be more appropriate to evaluate the AKD paper sizing efficiency.展开更多
Sizing is an inherent part of weaving works, consisting in the coating of the warp yarn with a polymeric adhesive, such as starch, in order to assist efficient weaving. The study is aimed to assess the effects of sque...Sizing is an inherent part of weaving works, consisting in the coating of the warp yarn with a polymeric adhesive, such as starch, in order to assist efficient weaving. The study is aimed to assess the effects of squeezed roller pressure, dryer temperature, yarn count, machine speed (rpm) on cotton fabric weaving. Coarser and finer cotton yarn samples were prepared using sizing solution BENSIZE 850. Different size box temperature, yarn count, fabric construction, machine speed, squeeze roller pressure were considered to construct different weaving designs to study yarn breakages parameter. A warping plan was designed on TAROKO V5.4 (190325) software. The results established that size box lower temperature and higher machine speed provide the smallest amount yarn break during weaving for coarser cotton yarn and the highest for finer cotton yarn. Size box higher temperature and lower machine speed provide maximum yarn breakage during weaving coarser cotton yarn and minimum for fine yarn. Size penetration is uniform, which provides a higher strength of the yarn to less breakage. This aspect of the research suggested that higher yarn strength gives a lesser amount of breakage.展开更多
Energy efficiency is closely related to the evolution of biological systems and is important to their information processing. In this work, we calculate the excitation probability of a simple model of a bistable biolo...Energy efficiency is closely related to the evolution of biological systems and is important to their information processing. In this work, we calculate the excitation probability of a simple model of a bistable biological unit in response to pulsatile inputs, and its spontaneous excitation rate due to noise perturbation. Then we analytically calculate the mutual information, energy cost, and energy efficiency of an array of these bistable units. We find that the optimal number of units could maximize this array's energy efficiency in encoding pulse inputs, which depends on the fixed energy cost. We conclude that demand for energy efficiency in biological systems may strongly influence the size of these systems under the pressure of natural selection.展开更多
Using total suspended solid (TSS) removal efficiency and hydraulic retention time (HRT) as design parameters a design guideline of a settling basin in a constructed wetland (CW) was suggested; as well as managem...Using total suspended solid (TSS) removal efficiency and hydraulic retention time (HRT) as design parameters a design guideline of a settling basin in a constructed wetland (CW) was suggested; as well as management of sediment and particle in the settling basin. The CW was desiEned to treat the piggery wastewater effluent from a wastewater treatment plant during dry days and stonnwater runoff from the surrounding paved area during wet days. The first settling basin (FSB) in the CVV was theoretically designed with a total storage volume (TSV) of 453 ms and HRT of 5.5 hr. The amount of sediment and particles settled at the FSB was high due to the sedimentation and interception of plants in the CVV. Dredging of sediments was performed when the retention rate at the FSB decreased to approximately 80%. Findings showed that the mean flow rate was 21.8 m3/hr less than the designed flow rate of 82.8 m3/hr indicating that the FSB was oversize and operated with longer HRT (20.7 hr) compared to the design HRT. An empirical model to estimate the length of the settling basin in the CW was developed as a function of HRT and desired TSS removal efficiency. Using the minimum tolerable TSS removal efficiency of 30%, the length of the FSB was estimated to be 31.2 m with 11.8 hr HRT.展开更多
Bio-inspired eco-friendly gold nanoparticles were synthesized by a green method using aqueous Plume- ria alba flower extract (PAFE). The use of 1% and 5% concentrations of PAFE resulted in two different sizes of P. ...Bio-inspired eco-friendly gold nanoparticles were synthesized by a green method using aqueous Plume- ria alba flower extract (PAFE). The use of 1% and 5% concentrations of PAFE resulted in two different sizes of P. alba gold nanoparticles, PAGNPsl and PAGNPs2, with surface plasmon resonance (SPR) peaks at 552 and 536 nm, respectively. Size-controlled formation of gold nanoparticles was indicated by the SPR shift observed with increasing concentration of PAFE. The accurate size and morphology of PAGNPs I and PAGNPs2 were determined by transmission electron microscope (TEM) analysis is found to be 28 + 5.6 and 15.6 4-3.4 nm, respectively, and those are spherical in shape. The antibacterial activity of PAGNPsl and PAGNPs2 was tested against Escherichia coil; the small-sized PAGNPs2 exhibited better antibacterial activity with a 16-mm zone of inhibition at a concentration of 400 txg/mL. Furthermore, the catalytic activity of PAGNPsl and PAGNPs2 was analyzed on six hazardous dyes; PAGNPs2 exhibited more pro- nounced catalytic activity than PAGNPsl. Among all of the dyes, 4-nitrophenol was most rapidly degraded to 4-aminophenol by PAGNPs2 within 5 min. The mechanism of catalysis in the presence of PAGNPsl and PAGNPs2 can be described as an electron transfer process from donor NaBH4 to an acceptor. The facile green synthesis of such eco-friendly nanoparticles in bulk suggests this method has potential industrial applications.展开更多
Industrial coal-fired boiler is an important air pollutant emission source in China. The chain-grate boiler is the most extensively used type of industrial coal-fired boiler. An electrical low-pressure impactor, and a...Industrial coal-fired boiler is an important air pollutant emission source in China. The chain-grate boiler is the most extensively used type of industrial coal-fired boiler. An electrical low-pressure impactor, and a Dekati? Low Pressure Impactor were applied to determine mass and number size distributions of PM10 at the inlet and the outlet of the particulate emission control devices at six coalfired chain-grate boilers. The mass size distribution of PM10 generated from coal-fired chain-grate boilers generally displays a bimodal distribution that contains a submicron mode and a coarse mode. The PM in the submicron mode for burning with raw coal contributes to 33% ± 10 % of PM10 emissions, much higher than those for pulverized boilers. And the PM in the submicron mode for burning with briquette contributes up to 86 % of PM10 emissions. Multiclones and scrubbers are not efficient for controlling PM10 emission. Their average collection efficiencies for sub-micron particle and super-micron particle are 34% and 78%, respectively. Operating conditions of industrial steam boilers have influence on PM generation. Peak of the submicron mode during normal operation period is larger than the start-up period.展开更多
基金National Natural Science Foundation of China(No.31370578)State Key Laboratory of Pulp and Paper Engineering,China(No.201508)
文摘The charge density of cellulose fibers is a key parameter in the papermaking systems,and this is particularly true for the Alkyl Ketene Dimer( AKD) paper sizing.Zeta potential and cationic demand are often used to characterize these charges.Generally,a similar sizing performance would be obtained when the fibers with similar morphology and charge characteristics are used.However,in a mill trial,it was shown that three bleached birch pulp samples,with similar fiber morphology,and zeta potential,had different AKD sizing behaviors.In this study,the surface charges of these pulp samples,measured using the polyelectrolyte titration methods,were investigated.The results showed that lower sizing efficiency of fibers were due to their lower surface charges.It was concluded that the direct measurement of surface charge of cellulose fibers can be more appropriate to evaluate the AKD paper sizing efficiency.
文摘Sizing is an inherent part of weaving works, consisting in the coating of the warp yarn with a polymeric adhesive, such as starch, in order to assist efficient weaving. The study is aimed to assess the effects of squeezed roller pressure, dryer temperature, yarn count, machine speed (rpm) on cotton fabric weaving. Coarser and finer cotton yarn samples were prepared using sizing solution BENSIZE 850. Different size box temperature, yarn count, fabric construction, machine speed, squeeze roller pressure were considered to construct different weaving designs to study yarn breakages parameter. A warping plan was designed on TAROKO V5.4 (190325) software. The results established that size box lower temperature and higher machine speed provide the smallest amount yarn break during weaving for coarser cotton yarn and the highest for finer cotton yarn. Size box higher temperature and lower machine speed provide maximum yarn breakage during weaving coarser cotton yarn and minimum for fine yarn. Size penetration is uniform, which provides a higher strength of the yarn to less breakage. This aspect of the research suggested that higher yarn strength gives a lesser amount of breakage.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11105062 and 11265014the Fundamental Research Funds for the Central Universities under Grant Nos LZUJBKY-2011-57 and LZUJBKY-2015-119
文摘Energy efficiency is closely related to the evolution of biological systems and is important to their information processing. In this work, we calculate the excitation probability of a simple model of a bistable biological unit in response to pulsatile inputs, and its spontaneous excitation rate due to noise perturbation. Then we analytically calculate the mutual information, energy cost, and energy efficiency of an array of these bistable units. We find that the optimal number of units could maximize this array's energy efficiency in encoding pulse inputs, which depends on the fixed energy cost. We conclude that demand for energy efficiency in biological systems may strongly influence the size of these systems under the pressure of natural selection.
基金supported by a grant (Code # 413-111-004) from Eco Innovation Project funded by Ministry of Environment of Korea government
文摘Using total suspended solid (TSS) removal efficiency and hydraulic retention time (HRT) as design parameters a design guideline of a settling basin in a constructed wetland (CW) was suggested; as well as management of sediment and particle in the settling basin. The CW was desiEned to treat the piggery wastewater effluent from a wastewater treatment plant during dry days and stonnwater runoff from the surrounding paved area during wet days. The first settling basin (FSB) in the CVV was theoretically designed with a total storage volume (TSV) of 453 ms and HRT of 5.5 hr. The amount of sediment and particles settled at the FSB was high due to the sedimentation and interception of plants in the CVV. Dredging of sediments was performed when the retention rate at the FSB decreased to approximately 80%. Findings showed that the mean flow rate was 21.8 m3/hr less than the designed flow rate of 82.8 m3/hr indicating that the FSB was oversize and operated with longer HRT (20.7 hr) compared to the design HRT. An empirical model to estimate the length of the settling basin in the CW was developed as a function of HRT and desired TSS removal efficiency. Using the minimum tolerable TSS removal efficiency of 30%, the length of the FSB was estimated to be 31.2 m with 11.8 hr HRT.
文摘Bio-inspired eco-friendly gold nanoparticles were synthesized by a green method using aqueous Plume- ria alba flower extract (PAFE). The use of 1% and 5% concentrations of PAFE resulted in two different sizes of P. alba gold nanoparticles, PAGNPsl and PAGNPs2, with surface plasmon resonance (SPR) peaks at 552 and 536 nm, respectively. Size-controlled formation of gold nanoparticles was indicated by the SPR shift observed with increasing concentration of PAFE. The accurate size and morphology of PAGNPs I and PAGNPs2 were determined by transmission electron microscope (TEM) analysis is found to be 28 + 5.6 and 15.6 4-3.4 nm, respectively, and those are spherical in shape. The antibacterial activity of PAGNPsl and PAGNPs2 was tested against Escherichia coil; the small-sized PAGNPs2 exhibited better antibacterial activity with a 16-mm zone of inhibition at a concentration of 400 txg/mL. Furthermore, the catalytic activity of PAGNPsl and PAGNPs2 was analyzed on six hazardous dyes; PAGNPs2 exhibited more pro- nounced catalytic activity than PAGNPsl. Among all of the dyes, 4-nitrophenol was most rapidly degraded to 4-aminophenol by PAGNPs2 within 5 min. The mechanism of catalysis in the presence of PAGNPsl and PAGNPs2 can be described as an electron transfer process from donor NaBH4 to an acceptor. The facile green synthesis of such eco-friendly nanoparticles in bulk suggests this method has potential industrial applications.
基金Acknowledgements This study was supported by the National Natural Science Foundation of China (Grant Nos. 41275121 and 41575119) and the National Key Basic Research and Development Program of China (No. 2013CB228505) and Beijing Municipal Science & Technology Commission (Grant No. Z161100000716004).
文摘Industrial coal-fired boiler is an important air pollutant emission source in China. The chain-grate boiler is the most extensively used type of industrial coal-fired boiler. An electrical low-pressure impactor, and a Dekati? Low Pressure Impactor were applied to determine mass and number size distributions of PM10 at the inlet and the outlet of the particulate emission control devices at six coalfired chain-grate boilers. The mass size distribution of PM10 generated from coal-fired chain-grate boilers generally displays a bimodal distribution that contains a submicron mode and a coarse mode. The PM in the submicron mode for burning with raw coal contributes to 33% ± 10 % of PM10 emissions, much higher than those for pulverized boilers. And the PM in the submicron mode for burning with briquette contributes up to 86 % of PM10 emissions. Multiclones and scrubbers are not efficient for controlling PM10 emission. Their average collection efficiencies for sub-micron particle and super-micron particle are 34% and 78%, respectively. Operating conditions of industrial steam boilers have influence on PM generation. Peak of the submicron mode during normal operation period is larger than the start-up period.