针对油浸式电力变压器瞬态温升计算效率过低的问题,该文提出本征正交分解-αATS(proper orthogonal decomposition-adaptive time stepping based onαfactor,POD-αATS)降阶自适应变步长瞬态计算方法。首先,推导变压器绕组瞬态温升计...针对油浸式电力变压器瞬态温升计算效率过低的问题,该文提出本征正交分解-αATS(proper orthogonal decomposition-adaptive time stepping based onαfactor,POD-αATS)降阶自适应变步长瞬态计算方法。首先,推导变压器绕组瞬态温升计算的有限元离散方程;其次,采用POD降阶算法改善传统瞬态计算中存在的条件数过大及方程阶数过高的问题;同时对于瞬态计算中的时间步长选择问题,提出适用于非线性问题的αATS变步长策略;然后,为验证方法的有效性,基于110 kV油浸式电力变压器绕组的基本结构建立二维八分区数值计算模型,同时将计算结果与基于110 kV绕组的温升实验结果进行对比。数值计算及实验结果表明,所提算法与全阶定步长算法在流场和温度场中的精度几乎相同,且流场计算效率提升约45倍,温度场计算效率提升约38倍,计算速度得到显著提高。这一点在温升实验中同样得到验证,说明该文所提算法的准确性、高效性及一定的工程实用性。展开更多
The world’s production of cocoa highly has grown since 1960.In West Africa,the production reached about 3,000,000 tons in 2012.More than 50%of the world’s production of cocoa comes nowadays from Côte d’Ivoire ...The world’s production of cocoa highly has grown since 1960.In West Africa,the production reached about 3,000,000 tons in 2012.More than 50%of the world’s production of cocoa comes nowadays from Côte d’Ivoire and Ghana and Côte d’Ivoire is the biggest producer.After harvesting,the empty shells,considered as non-useful wastes,are abandoned in the fields where they become a source of pollution.That yields millions of tons of biomass that can be converted into charcoal,instead of being sources of pollution.In the present work,the drying kinetics of the empty wet shells were studied.Then,charcoal production by pyrolysis of those empty shells of cocoa pods was performed,using a carbonisation stove fitted with a chimney.The study showed that the empty shells have a high moisture content.The different phases of the drying were observed.The study compared the drying rates and the diffusion coefficients of a small sample and a big sample.Two experiences of carbonisation of the empty shells were successfully carried out.For the first experiment,the pyrolysis temperatures were recorded and the charcoal mass efficiency calculated.For the second experiment,the temperatures were higher and the result was colored charcoals.The colorations disappeared after some hours.展开更多
The use of plant extracts as antifungal agents is gaining increasing attention, particularly for the control of black pod disease in cocoa. Despite extensive research, current strategies haven’t been entirely effecti...The use of plant extracts as antifungal agents is gaining increasing attention, particularly for the control of black pod disease in cocoa. Despite extensive research, current strategies haven’t been entirely effective. This study evaluated the effectiveness of Cymbopogon citratus and Blumea balsamifora leaf extracts, both individually and in combination, against Phytophthora megakarya. We assessed the efficacy of the most promising combination (75% B. balsamifera, 25% C. citratus) after storage at room temperature for up to 9 days. Agar microdilution and in vivo bioassays were conducted to determine antifungal susceptibility and effectiveness. Blumea extract exhibited the highest overall inhibitory activity, with the lowest minimum inhibitory concentration (117 µl mL−1) while C. citratus had a narrower range of MIC (146 to 233 µl mL−1). The combination of C. citratus and B. balsamifera demonstrated a synergistic effect against P. megakarya, achieving growth inhibition on V8 media (92.72 ± 4.20% to 100%) and on artificially infected detached pod cortex (92.24 ± 4.53% to 98.75 ± 1.25%), which was not significantly different from the positive control (Ridomil). Furthermore, this combination maintained its effectiveness for up to 9 days at room temperature. These findings suggest that combining plant extracts can enhance their antifungal properties.展开更多
针对风火打捆(wind-thermal-bundled,WTB)系统在受到干扰时可能由于阻尼不足而出现的低频振荡现象以及较高的网损会导致运行成本的增加和阻碍“双碳”目标实现的问题,提出了一种电力系统稳定器(power system stabilizer,PSS)与统一潮流...针对风火打捆(wind-thermal-bundled,WTB)系统在受到干扰时可能由于阻尼不足而出现的低频振荡现象以及较高的网损会导致运行成本的增加和阻碍“双碳”目标实现的问题,提出了一种电力系统稳定器(power system stabilizer,PSS)与统一潮流控制器(unified power flow controller,UPFC)附加功率振荡阻尼控制器(power oscillation damping,POD)参数和UPFC安装位置协调优化策略方法。首先,基于Matlab构建了风火打捆外送系统和控制器模型。然后,利用多目标樽海鞘优化算法(multi-objective salp swarm algorithm,MSSA),将协调优化问题转化为多目标优化问题。目标函数设计中考虑了UPFC装置的调节特性。最后,采用IEEE 4机2区系统和16机5区系统进行多种工况下的仿真。仿真结果显示,协调优化后的控制器可以提高系统阻尼,维持发电机转速的稳定,抑制低频振荡引起的系统有功、电压等的波动,同时降低了系统的有功网损,提高了系统稳定性和运行经济性。MSSA在工程问题上的应用得到了补充。展开更多
针对当前油浸式电力变压器绕组瞬态温升仿真中,采用固定时间步长效率低的问题,提出一种混合变步长方法。首先,采用初始解优化算法,有效减少计算过程中方程的迭代次数;其次,结合本征正交分解算法(properorthogonal decomposition,POD),...针对当前油浸式电力变压器绕组瞬态温升仿真中,采用固定时间步长效率低的问题,提出一种混合变步长方法。首先,采用初始解优化算法,有效减少计算过程中方程的迭代次数;其次,结合本征正交分解算法(properorthogonal decomposition,POD),改善大规模有限元方程组存在的阶数过高、条件数过大的问题,提高了方程的求解效率和数值稳定性;第三,提出自适应(adaptivetimestepping,ATS)-启发式(heuristic time stepping,HTS)混合变步长算法,通过对时间步长的自适应与启发式调整,有效解决瞬态计算中计算效率与计算精度的对立问题;最后,建立油浸式电力变压器绕组二维单分区分匝的流热耦合仿真模型,以验证所提算法的正确性与高效性。数值计算结果表明:在流场中,与固定步长的计算结果相比,混合变步长算法的误差小于0.46%,计算效率提升了18.45倍;在温度场中,与固定步长的计算结果相比,所提算法的误差小于0.04%,计算效率提升了6倍。同时,通过与传统变步长算法的计算结果对比,说明所提混合变步长算法在计算精度、计算效率及变步长效果方面均具有一定优势。此外,还探讨混合变步长计算中,不同的参数设置对瞬态计算结果及状态变化过程的影响,为其工程应用奠定了一定基础。展开更多
Objective:To search for an efficient and inexpensive source of phytoconstituents with antioxidant potential and health promoting traits from bark and empty pods of Acacia auriculiformis （A.auriculiformis）.Methods:Sa...Objective:To search for an efficient and inexpensive source of phytoconstituents with antioxidant potential and health promoting traits from bark and empty pods of Acacia auriculiformis （A.auriculiformis）.Methods:Samples of bark and empty pod extracts were analyzed for bioactives（phenolics,flavonoids and proanthocyanidins） and subjected to free radical scavenging activity on DPPH<sup>*</sup>,ABTS<sup>?</sup>,OH<sup>?</sup>,O<sub>2</sub><sup>*</sup>,and NO along with the determination of reducing power, iron chelating activity and peroxidation inhibition.Defensive action of extracts on biomolecules and cell membranes were evaluated by DNA nicking assay and haemolysis inhibition assay respectively,α-amylase andα-glucosidase inhibitory potentials were also determined. Results:All the bioactives analyzed were higher in bark（B） than empty pods（EP）[TPC:B （574.51±16.11）;EP（96.80±3.45） mg GAE/g.TFC:B（94.71±7.65）;EP（24（?）87±20.45） mg RE/g. Proanthocyanidins:B（2.81±0.31）;EP（1.25±0.01） mg LE/100 g DM]except flavonoids.Both the extracts showed higher quenching capacity on DPPH and ABTS（DPPH:B（0.21±0.01）;EP（1.51±0.17） g extract/g DPPH.ABTS:B（111 519.14±79 340.91）;EP（80 232.55±32 894.12） mmol TE/g） with the FRAP of B（84 515.63±3 350.69） and EP（47 940.79±1 257.60） mmol Fe（（?））/g.Iron chelation was not observed.In addition,they showed lower quenching activity on OH<sup>?</sup>（B（48.95±1.72）;EP（34.94±1.62）%） and equivalent quenching on O<sub>2</sub><sup>?</sup>（B（53.47±3.92）;EP（24.41±2.61）%）,NO（B（49.04±5.04）; EP（51.00±5.13）%）,peroxidation inhibition（B（67.50±5.50）;EP（55.l±2.3）%） and antihaemolytic potential（B（87.60±6.84）%） towards authentic antioxidant standards.Interestingly,Empty pod extracts are devoid of antihaemolytic activity.Both the extracts showed dose dependent DNA protection.Besides this,bark and empty pod extracts exhibited dual inhibiting potential againstα-amylase andα-glucosidase enzymes.Conclusions:On summarization,it insinuated that both bark and empty pods can be used for the preparation of antioxidant/nutraceutical supplements and in anti-diabetic formulations.展开更多
Number of pods per plant and number of seeds per pod are quantitative,multigenic traits and important components of yield in soybean[Glycine max(L.)Merr.].Pods are distributed unevenly in the upper,middle,and lower se...Number of pods per plant and number of seeds per pod are quantitative,multigenic traits and important components of yield in soybean[Glycine max(L.)Merr.].Pods are distributed unevenly in the upper,middle,and lower segments of the plant and this distribution is affected by sowing date(SD).A population of four-way recombinant inbred lines(FW-RIL),containing 160 F2:8 individuals,was generated from the cross(Kenfeng 14×Kenfeng 15)×(Heinong 48×Kenfeng 19).A linkage map consisting of 275 simple sequence repeat(SSR)markers was used to map quantitative trait loci(QTL)associated with the production of one,two,three,and four seeds per pod in the upper,middle,and lower segments of plants at two SDs,totaling 12 measurements per SD.A wide range of variation in the twelve characteristics was observed among the four parental lines and the FW-RIL population at the two SDs.The effect of SD2(May 17,2016)on pod number was stronger than that of SD1(May 7,2016)because the heritability of each trait in the SD1 experiment was generally greater than that of SD2.The study identified 76 QTL controlling pod number,with the phenotypic variation explained by each QTL ranging from 1.86%to 13.71%.The numbers of QTL controlling one,two,three,and four seeds per pod were 28,23,23,and 23,respectively.There were 30,28,and 28 QTL controlling the pod number in the upper,middle,and lower segments of the plant,respectively.Forty-five QTL were identified at SD1 and 38 QTL were identified at SD2.Seventeen QTL were associated with pod-number traits.The QTL qPNA1–3 was associated with the number of pods containing one seed in the middle segment of the plant at both SDs.Sixty-three QTL were published QTL(common areas existed when integrating on a map GmComposite2003 of Wm82 based on left and right markers).and 13 QTL related to pod number were newly discovered.These results provide a reference for breeders to improve soybean yield by combining advantageous alleles for these QTL.Future studies may reveal candidate genes for these QTL and identify causal alleles for markerassisted selection.展开更多
文摘针对油浸式电力变压器瞬态温升计算效率过低的问题,该文提出本征正交分解-αATS(proper orthogonal decomposition-adaptive time stepping based onαfactor,POD-αATS)降阶自适应变步长瞬态计算方法。首先,推导变压器绕组瞬态温升计算的有限元离散方程;其次,采用POD降阶算法改善传统瞬态计算中存在的条件数过大及方程阶数过高的问题;同时对于瞬态计算中的时间步长选择问题,提出适用于非线性问题的αATS变步长策略;然后,为验证方法的有效性,基于110 kV油浸式电力变压器绕组的基本结构建立二维八分区数值计算模型,同时将计算结果与基于110 kV绕组的温升实验结果进行对比。数值计算及实验结果表明,所提算法与全阶定步长算法在流场和温度场中的精度几乎相同,且流场计算效率提升约45倍,温度场计算效率提升约38倍,计算速度得到显著提高。这一点在温升实验中同样得到验证,说明该文所提算法的准确性、高效性及一定的工程实用性。
基金ASCAD(l’Académie des Sciences,des Cultures,des Arts d’Afrique et de ses Diasporas)for its support to his renewable energy program。
文摘The world’s production of cocoa highly has grown since 1960.In West Africa,the production reached about 3,000,000 tons in 2012.More than 50%of the world’s production of cocoa comes nowadays from Côte d’Ivoire and Ghana and Côte d’Ivoire is the biggest producer.After harvesting,the empty shells,considered as non-useful wastes,are abandoned in the fields where they become a source of pollution.That yields millions of tons of biomass that can be converted into charcoal,instead of being sources of pollution.In the present work,the drying kinetics of the empty wet shells were studied.Then,charcoal production by pyrolysis of those empty shells of cocoa pods was performed,using a carbonisation stove fitted with a chimney.The study showed that the empty shells have a high moisture content.The different phases of the drying were observed.The study compared the drying rates and the diffusion coefficients of a small sample and a big sample.Two experiences of carbonisation of the empty shells were successfully carried out.For the first experiment,the pyrolysis temperatures were recorded and the charcoal mass efficiency calculated.For the second experiment,the temperatures were higher and the result was colored charcoals.The colorations disappeared after some hours.
文摘The use of plant extracts as antifungal agents is gaining increasing attention, particularly for the control of black pod disease in cocoa. Despite extensive research, current strategies haven’t been entirely effective. This study evaluated the effectiveness of Cymbopogon citratus and Blumea balsamifora leaf extracts, both individually and in combination, against Phytophthora megakarya. We assessed the efficacy of the most promising combination (75% B. balsamifera, 25% C. citratus) after storage at room temperature for up to 9 days. Agar microdilution and in vivo bioassays were conducted to determine antifungal susceptibility and effectiveness. Blumea extract exhibited the highest overall inhibitory activity, with the lowest minimum inhibitory concentration (117 µl mL−1) while C. citratus had a narrower range of MIC (146 to 233 µl mL−1). The combination of C. citratus and B. balsamifera demonstrated a synergistic effect against P. megakarya, achieving growth inhibition on V8 media (92.72 ± 4.20% to 100%) and on artificially infected detached pod cortex (92.24 ± 4.53% to 98.75 ± 1.25%), which was not significantly different from the positive control (Ridomil). Furthermore, this combination maintained its effectiveness for up to 9 days at room temperature. These findings suggest that combining plant extracts can enhance their antifungal properties.
文摘针对当前油浸式电力变压器绕组瞬态温升仿真中,采用固定时间步长效率低的问题,提出一种混合变步长方法。首先,采用初始解优化算法,有效减少计算过程中方程的迭代次数;其次,结合本征正交分解算法(properorthogonal decomposition,POD),改善大规模有限元方程组存在的阶数过高、条件数过大的问题,提高了方程的求解效率和数值稳定性;第三,提出自适应(adaptivetimestepping,ATS)-启发式(heuristic time stepping,HTS)混合变步长算法,通过对时间步长的自适应与启发式调整,有效解决瞬态计算中计算效率与计算精度的对立问题;最后,建立油浸式电力变压器绕组二维单分区分匝的流热耦合仿真模型,以验证所提算法的正确性与高效性。数值计算结果表明:在流场中,与固定步长的计算结果相比,混合变步长算法的误差小于0.46%,计算效率提升了18.45倍;在温度场中,与固定步长的计算结果相比,所提算法的误差小于0.04%,计算效率提升了6倍。同时,通过与传统变步长算法的计算结果对比,说明所提混合变步长算法在计算精度、计算效率及变步长效果方面均具有一定优势。此外,还探讨混合变步长计算中,不同的参数设置对瞬态计算结果及状态变化过程的影响,为其工程应用奠定了一定基础。
基金University Grants Commission (UGC),New Delhi,India(F.No.34-259\2008)for the financial assistance
文摘Objective:To search for an efficient and inexpensive source of phytoconstituents with antioxidant potential and health promoting traits from bark and empty pods of Acacia auriculiformis （A.auriculiformis）.Methods:Samples of bark and empty pod extracts were analyzed for bioactives（phenolics,flavonoids and proanthocyanidins） and subjected to free radical scavenging activity on DPPH<sup>*</sup>,ABTS<sup>?</sup>,OH<sup>?</sup>,O<sub>2</sub><sup>*</sup>,and NO along with the determination of reducing power, iron chelating activity and peroxidation inhibition.Defensive action of extracts on biomolecules and cell membranes were evaluated by DNA nicking assay and haemolysis inhibition assay respectively,α-amylase andα-glucosidase inhibitory potentials were also determined. Results:All the bioactives analyzed were higher in bark（B） than empty pods（EP）[TPC:B （574.51±16.11）;EP（96.80±3.45） mg GAE/g.TFC:B（94.71±7.65）;EP（24（?）87±20.45） mg RE/g. Proanthocyanidins:B（2.81±0.31）;EP（1.25±0.01） mg LE/100 g DM]except flavonoids.Both the extracts showed higher quenching capacity on DPPH and ABTS（DPPH:B（0.21±0.01）;EP（1.51±0.17） g extract/g DPPH.ABTS:B（111 519.14±79 340.91）;EP（80 232.55±32 894.12） mmol TE/g） with the FRAP of B（84 515.63±3 350.69） and EP（47 940.79±1 257.60） mmol Fe（（?））/g.Iron chelation was not observed.In addition,they showed lower quenching activity on OH<sup>?</sup>（B（48.95±1.72）;EP（34.94±1.62）%） and equivalent quenching on O<sub>2</sub><sup>?</sup>（B（53.47±3.92）;EP（24.41±2.61）%）,NO（B（49.04±5.04）; EP（51.00±5.13）%）,peroxidation inhibition（B（67.50±5.50）;EP（55.l±2.3）%） and antihaemolytic potential（B（87.60±6.84）%） towards authentic antioxidant standards.Interestingly,Empty pod extracts are devoid of antihaemolytic activity.Both the extracts showed dose dependent DNA protection.Besides this,bark and empty pod extracts exhibited dual inhibiting potential againstα-amylase andα-glucosidase enzymes.Conclusions:On summarization,it insinuated that both bark and empty pods can be used for the preparation of antioxidant/nutraceutical supplements and in anti-diabetic formulations.
基金the financial support for this study provided by grants from the Natural Science Foundation of Heilongjiang Province, China (LC201610) to Hailong Ning
文摘Number of pods per plant and number of seeds per pod are quantitative,multigenic traits and important components of yield in soybean[Glycine max(L.)Merr.].Pods are distributed unevenly in the upper,middle,and lower segments of the plant and this distribution is affected by sowing date(SD).A population of four-way recombinant inbred lines(FW-RIL),containing 160 F2:8 individuals,was generated from the cross(Kenfeng 14×Kenfeng 15)×(Heinong 48×Kenfeng 19).A linkage map consisting of 275 simple sequence repeat(SSR)markers was used to map quantitative trait loci(QTL)associated with the production of one,two,three,and four seeds per pod in the upper,middle,and lower segments of plants at two SDs,totaling 12 measurements per SD.A wide range of variation in the twelve characteristics was observed among the four parental lines and the FW-RIL population at the two SDs.The effect of SD2(May 17,2016)on pod number was stronger than that of SD1(May 7,2016)because the heritability of each trait in the SD1 experiment was generally greater than that of SD2.The study identified 76 QTL controlling pod number,with the phenotypic variation explained by each QTL ranging from 1.86%to 13.71%.The numbers of QTL controlling one,two,three,and four seeds per pod were 28,23,23,and 23,respectively.There were 30,28,and 28 QTL controlling the pod number in the upper,middle,and lower segments of the plant,respectively.Forty-five QTL were identified at SD1 and 38 QTL were identified at SD2.Seventeen QTL were associated with pod-number traits.The QTL qPNA1–3 was associated with the number of pods containing one seed in the middle segment of the plant at both SDs.Sixty-three QTL were published QTL(common areas existed when integrating on a map GmComposite2003 of Wm82 based on left and right markers).and 13 QTL related to pod number were newly discovered.These results provide a reference for breeders to improve soybean yield by combining advantageous alleles for these QTL.Future studies may reveal candidate genes for these QTL and identify causal alleles for markerassisted selection.
