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Reactor Network Synthesis for Waste Reduction Using Instantaneous Value of Environmental Index 被引量:2
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作者 陈启石 冯霄 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2008年第1期155-158,共4页
Waste reduction is gaining importance as the preferred means of pollution prevention. Reactor network synthesis is one of the key parts of chemical process synthesis. In this study, a geometric approach to reactor net... Waste reduction is gaining importance as the preferred means of pollution prevention. Reactor network synthesis is one of the key parts of chemical process synthesis. In this study, a geometric approach to reactor network synthesis for waste reduction is presented. The bases of the approach are potential environment impact (PEI) rate-law expression, PEI balance and the instantaneous value of environmental indexes. The instantaneous value can be derived using the PEI balance, PEI rate-law expression and the environmental indexes. The optimal reactor networks with the minimum generation of potential environment impact are geometrically derived by comparing with areas of the corresponding regions. From the case study involving complex reactions, the approach does not involve solving the complicated mathematical problem and can avoid the dimension limitation in the attainable region approach. 展开更多
关键词 instantaneous value of environmental indexes reactor network synthesis potential environmental impact waste reduction
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Sprouting Value Index and Viability Percentage: An Integrated Measure of Vegetative Planting Material
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作者 Justin R. Nayagam 《Journal of Agricultural Science and Technology(B)》 2016年第5期330-334,共5页
Rooting ability of indole 3-butyric acid (IBA)-induced stem cuttings in vegetative regeneration experiments depends on various parameters, which can be entrenched using sprouting value index (SVI), a mathematical ... Rooting ability of indole 3-butyric acid (IBA)-induced stem cuttings in vegetative regeneration experiments depends on various parameters, which can be entrenched using sprouting value index (SVI), a mathematical approach. In this study, field studies were carried out in Tabebuia rosea to generate clonal planting stock regeneration using three rooting medium at a location in Central Kerala, Peninsular India, for three consecutive years from October 2014 till June 2016 at four months regular intervals. Three IBA concentrations, viz., 200, 500 and 1,000 ppm, have been used and the data obtained was evaluated using SVI method in order to establish the suitable medium, which gives the maximum rooting results. Control cuttings did not record rooting in any of the trials. The high SVI was obtained when stem root cuttings planted in root trainers with coir pith compost (RTCP) for all the three concentration of IBA applied. Sprouting percentage was marked up and the delay in completion of sprouting/rooting initiation decreased by the use of IBA treatment. 展开更多
关键词 Pink trumpet tree sprouting value index rooting ability indole 3-butyric acid.
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Effects of SPAD Decline Value of Mid-season Hybrid Rice Leaves after Full-heading Stage on Productivity of Rice Fertilized with Nitrogen 被引量:1
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作者 徐富贤 何希德 +5 位作者 熊洪 张林 郭晓艺 朱永川 周兴兵 刘茂 《Agricultural Science & Technology》 CAS 2013年第1期149-154,共6页
[Objective] The aim was to research relationship between SPAD decline index after full-heading stage (SDIFHS) and productivity of rice. fertilized with nitro- gen in order to provide theoretical and practical refere... [Objective] The aim was to research relationship between SPAD decline index after full-heading stage (SDIFHS) and productivity of rice. fertilized with nitro- gen in order to provide theoretical and practical references for selection and breed- ing of rice varieties. [Method] From 2008 to 2010, 18 mid-season hybrid rice vari- eties were researched every year to explore relationship' between SDIFHS and pro- ductivity of rice fertilized with nitrogen. [Result] The productivity of rice fertilized with nitrogen was of extremely significant positive corretation with SDIFHS, because the higher SPAD decline index is, the higher LAI decline index and the transformation ratio of dry matter to spikes in overground plant would be. [Conclusion] The re- search established a new method to predict productivity of rice fertilized with nitro- gen based on SPAD decline index. 展开更多
关键词 Mid-season hybrid rice Decline index of SPAD value Productivity of rice fertilized with nitrogen
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The Convergence Rate of Fréchet Distribution under the Second-Order Regular Variation Condition
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作者 Xilai Dai 《Journal of Applied Mathematics and Physics》 2024年第5期1597-1605,共9页
In this article we consider the asymptotic behavior of extreme distribution with the extreme value index γ>0 . The rates of uniform convergence for Fréchet distribution are constructed under the second-order ... In this article we consider the asymptotic behavior of extreme distribution with the extreme value index γ>0 . The rates of uniform convergence for Fréchet distribution are constructed under the second-order regular variation condition. 展开更多
关键词 Convergence Rate Second-Order Regular Variation Condition Fréchet Distribution Extreme value index
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Critical Value of CO of Forecasting Coal Spontaneous Combustion 被引量:7
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作者 何启林 戴广龙 王德明 《Journal of China University of Mining and Technology》 2003年第2期121-125,共5页
CO has been used widely in the production process of colliery as an index gas to predict spontaneous combustion of coal. But in some collieries there are CO gas in the upper corner of the face all the times, sometime ... CO has been used widely in the production process of colliery as an index gas to predict spontaneous combustion of coal. But in some collieries there are CO gas in the upper corner of the face all the times, sometime CO gas even exceeds the regulated critical index. This phenomenon is much more obvious in the fully-mechanized longwall face and fully-mechanized longwall and top-coal caving face. Although many measures of fire-proof and fire-extinguishing have been adopted, the flowing amount of CO gas can be only decreasd, but can not be eliminated completely. Using the different kinds of coal, the experiment of coal oxidation was made at the low temperature. The experiment indicates that some kinds of coal can produce CO under the condition of normal temperature oxidation, sometime the CO consistency is very high, and the intension of CO can be decreased with oxidation time prolonging. Selecting rational critical value of CO is the kev to predicting spontaneous combustion of coal correctly and reliably. The problem of selecting retional critical value of CO was studied. Finally, the amount of CO gas released by different kinds of coal was obtained under normal temperature condition. 展开更多
关键词 coal spontaneous combustion index gas t critical value
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Target reliability index for serviceability limit state of single piles 被引量:3
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作者 边晓亚 郑俊杰 +1 位作者 徐志军 章荣军 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第1期310-316,共7页
The objective is to develop an approach for the determination of the target reliability index for serviceability limit state(SLS) of single piles. This contributes to conducting the SLS reliability-based design(RBD) o... The objective is to develop an approach for the determination of the target reliability index for serviceability limit state(SLS) of single piles. This contributes to conducting the SLS reliability-based design(RBD) of piles. Based on a two-parameter,hyperbolic curve-fitting equation describing the load-settlement relation of piles, the SLS model factor is defined. Then, taking into account the uncertainties of load-settlement model, load and bearing capacity of piles, the formula for computing the SLS reliability index(βsls) is obtained using the mean value first order second moment(MVFOSM) method. Meanwhile, the limit state function for conducting the SLS reliability analysis by the Monte Carlo simulation(MCS) method is established. These two methods are finally applied to determine the SLS target reliability index. Herein, the limiting tolerable settlement(slt) is treated as a random variable. For illustration, four load test databases from South Africa are compiled again to conduct reliability analysis and present the recommended target reliability indices. The results indicate that the MVFOSM method overestimates βsls compared to that computed by the MCS method. Besides, both factor of safety(FS) and slt are key factors influencing βsls, so the combination of FS and βsls is welcome to be used for the SLS reliability analysis of piles when slt is determined. For smaller slt, pile types and soils conditions have significant influence on the SLS target reliability indices; for larger slt, slt is the major factor having influence on the SLS target reliability indices. This proves that slt is the most key parameter for the determination of the SLS target reliability index. 展开更多
关键词 single pile serviceability limit state target reliability index mean value first order second moment method Monte Carlo simulation
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Distributed Trimmed Hill Estimator
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作者 Tao Guo 《Journal of Applied Mathematics and Physics》 2023年第12期4000-4015,共16页
Proceeded from trimmed Hill estimators and distributed inference, a new distributed version of trimmed Hill estimator for heavy tail index is proposed. Considering the case where the number of observations involved in... Proceeded from trimmed Hill estimators and distributed inference, a new distributed version of trimmed Hill estimator for heavy tail index is proposed. Considering the case where the number of observations involved in each machine can be either the same or different and either fixed or varying to the total sample size, its consistency and asymptotic normality are discussed. Simulation studies are particularized to show the new estimator performs almost in line with the trimmed Hill estimator. 展开更多
关键词 Extreme value index Distributed Trimmed Hill Estimator
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Estimation of above-ground biomass and carbon stock of an invasive woody shrub in the subtropical deciduous forests of Doon Valley,western Himalaya,India 被引量:8
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作者 Gautam Mandal S.P.Joshi 《Journal of Forestry Research》 SCIE CAS CSCD 2015年第2期291-305,共15页
This study describes the different parameters used to derive the allometric equation for calculating the biomass of an invasive woody shrub Lantana camara L.from the subtropical conditions of western Himalaya.It ident... This study describes the different parameters used to derive the allometric equation for calculating the biomass of an invasive woody shrub Lantana camara L.from the subtropical conditions of western Himalaya.It identifies the most accurate and convenient method for biomass calculation by comparing destructive with nondestructive methodology.Different parameters were measured on a wide range of Lantana from different community levels for the non-destructive calculation of total aboveground biomass.Different explanatory variables were identified and measured such as basal diameter either as a single independent variable or in combination with plant height.The other suitable combinations of available independent variables include crown length,crown width,crown area,crown volume and coverage of the plant.Amongst the wide range of allometric equations used with different variables,the equation with D2 H as a variable was found to be the most suitable estimator of biomass calculation for Lantana.Sahastradhara,being the most disturbed area due to its high tourist activity round the year,showed maximum coverage(58.57 % ha-1),highest biomass(13,559.60 kg ha-1) and carbon density(6,373.01 kg ha-1)of Lantana.The degree of Lantana’s invasiveness in subtropical conditions was also calculated on the basis of importance value index(IVI).The maximum IVI(22.77)and mean coverage(26.8 % ha-1) was obtained from the areas near Jolly Grant airport,indicating that physically disturbed areas are more suitable for the growth of Lantana,which may significantly increase shrub biomass.The importance of incorporating allometric equations in calculation of shrub biomass,and its role in atmospheric carbon assimilation has thus been highlighted through the findings of this study. 展开更多
关键词 Above ground carbon pools Allometric regression equations Carbon density Importance value index(IVI) Shrub biomass
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Diversity and structural composition of species in dipterocarp forests:a study from Fasiakhali Wildlife Sanctuary, Bangladesh 被引量:4
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作者 S.C.Das M.S.Alam M.A.Hossain 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第5期1241-1249,共9页
Fasiakhali Wildlife Sanctuary is a protected area composed of tropical remnant rainforest that harbor substantial number of large,old Garjan(Dipterocarpus spp.)trees.The present study assessed composition,structure ... Fasiakhali Wildlife Sanctuary is a protected area composed of tropical remnant rainforest that harbor substantial number of large,old Garjan(Dipterocarpus spp.)trees.The present study assessed composition,structure and diversity of the species in this protected area.A total of 32 trees species were recorded with DBH ≥ 11 cm belonging to 24 genera and 19 families.The forest is low in plant diversity as represented by Shannon–Wiener diversity and Simpson Dominance indices.Dipterocarpus turbinatus was the most dominant species with maximum relative density,frequency,dominance,and importance value index.Syzygium firmum and Tectona grandis followed in terms of dominance.The structural composition indicated higher number of individuals in the medium growth classes(41 to 〈 511 cm DBH and 16–20 m height ranges),whereas D.turbinatus was the only species that dominated most of the growth classes.Poor stem density in lower growth classes indicated meager recruitment of regeneration which may be due to lower annual precipitation,increased grazing and encroachments.This study will help to understand the patterns of tree species composition and diversity in the remnant dipterocarp forests of Bangladesh.It will also contribute to identifying threatened plants to undertake D.turbinatus based conservation and sustainable management of the Fasiakhali Wildlife Sanctuary. 展开更多
关键词 Species diversity Structural composition Protected area Importance value index Cluster analysis
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Changes in tree species diversity and dominance across a disturbance gradient in Nepalese Sal (Shorea robusta Gaertn. f.) forests 被引量:3
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作者 Indra Prasad Sapkota Mulualem Tigabu Per Christer Odén 《Journal of Forestry Research》 SCIE CAS CSCD 2010年第1期25-32,I0001,I0002,共10页
Disturbance is often touted as a management tool, as moderate disturbance is believed to enhance diversity; thus an understanding of frequent and fluctuating disturbance regimes in forests and their effects on stand s... Disturbance is often touted as a management tool, as moderate disturbance is believed to enhance diversity; thus an understanding of frequent and fluctuating disturbance regimes in forests and their effects on stand structure, dominance and diversity is very crucial. Here, the effects of different disturbance regimes, along a gradient, on diversity and dominance of five Shorea robusta Gaertn. f.-dominated forests were investigated in 25 one-ha plots in Nepal. A total of 67 tree species were recorded; of which 41 species were encountered in least disturbed and 10 species in beavily disturbed forest. Significant variations among forests were observed for all measures of alpha diversity. Alpha diversity measures declined linearly along a disturbance gradient while dominance increased linearly. Relative basal area of S. robusta increased as the level of disturbance increased, which in turn produced more than two-fold higher important value index in heavily disturbed forest than the least disturbed forest. All alpha diversity measures declined in an order of three with increasing relative basal area of S. robusta. The similarity in species composition between each pair of disturbed forests was generally low (Jaccard's similarity index 〈 57%), suggesting a higher Beta diversity, It can be concluded that diversity of Sal forests declines with increasing magnitude of disturbance, which in turn favors a higher domi- nance of S. robusta. Controlling the population of the dominant species, mainly S. robusta, is recommended to enhance diversity and to achieve multiple-use forest management objectives. 展开更多
关键词 Human pressure disturbance ecology species richness alpha diversity important value index
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Woody plant diversity,structure and regeneration in the Ambo State Forest,South Gondar Zone,Northwest Ethiopia 被引量:2
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作者 Solomon Melaku Melese Belayneh Ayele 《Journal of Forestry Research》 SCIE CAS CSCD 2017年第1期133-144,共12页
For this study in the Ambo State Forest on woody plant diversity, structure and regeneration, 70 quadrats, each 25 m by 25 m, were selected using a systematic random sampling technique and intervals of 100 m along a t... For this study in the Ambo State Forest on woody plant diversity, structure and regeneration, 70 quadrats, each 25 m by 25 m, were selected using a systematic random sampling technique and intervals of 100 m along a transect line. For assessing seedlings and saplings, two 2 × 10 m sub quadrats were set upon opposite sides of each main quadrat. Data on species diversity, abundance, structure, basal area, density, frequency and regeneration status were collected and analyzed using standard procedures and programs. Of 58 woody plant species identified, 69 % were trees, 16 % were shrubs, 12 % were tree/shrubs and 4 % were climbers. Fabaceae was the most speciesrich family comprising 17 species. The Shannon-Weiner diversity index was 2.73, and evenness was 0.67. The population structure in the cumulative diameter class frequency distribution revealed an interrupted and inverted J-shape with a very high decrease in higher diameter class. Acacia lahai (49 %) was the most important woody species with the highest importance value index. To maintain balanced structure, enhanced regeneration and protecting the forest from selective cutting are recommended. 展开更多
关键词 Ambo Forest DIVERSITY Structure -Importance value index Regeneration status
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Effect of exclosure ages on woody plant structure,diversity and regeneration potential in the western Tigray region of Ethiopia 被引量:1
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作者 Tsegay Gebregerges Zewdu K.Tessema Emiru Birhane 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第3期693-703,共11页
Exclosure is a method of rehabilitating degraded lands by protecting them from the interference of animals and from human encroachment, and is used to regenerate native vegetation as a way to reduce soil erosion, incr... Exclosure is a method of rehabilitating degraded lands by protecting them from the interference of animals and from human encroachment, and is used to regenerate native vegetation as a way to reduce soil erosion, increase rain water infiltration and provide fodder and woody biomass in degraded grazing lands. Therefore, we studied woody plant structure, diversity and regeneration potentials in 5-and 10-year grazing exclosures in comparison with open grazed sites in a semi-arid environment. Data on species diversity, abundance, structure, basal area, frequency, density, and regeneration status were collected from 270 sample plots. Forty-one woody species representing 20 families were identified, with 18, 28 and 38 species found in open grazed areas, and in 5-and 10-year grazing exclosures, respectively. The 10-year grazing exclosures had a higher(P <0.05) species richness and plant densities compared to the 5-year grazing exclosures and the open grazed areas. The population structure and regeneration status of woody species in both grazing exclosures showed an inverted J-shape, indicating a healthy regeneration status, whereas hampered regeneration was observed in open grazed areas. The establishment of grazing exclosures had positive effects in restoring woody plant diversity and improving vegetation structure and regeneration potentials of degraded grazing lands. 展开更多
关键词 Basal area DIVERSITY Important value index Population structure Regeneration status Species composition EXCLOSURES
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Tree Species Composition and Diversity in the Riparian Forest of Lake Barombi Kotto, Cameroon 被引量:1
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作者 Awo Miranda Egbe Pascal Tabi Tabot Fonge Beatrice Ambo 《American Journal of Plant Sciences》 2021年第1期127-145,共19页
Tree species composition and diversity were investigated in the riparian forest around Lake Barombi Kotto, Cameroon. This study aimed at determining</span><span style="font-family:""> </s... Tree species composition and diversity were investigated in the riparian forest around Lake Barombi Kotto, Cameroon. This study aimed at determining</span><span style="font-family:""> </span><span style="font-family:Verdana;">the tree species composition, population structure, and providing evidence of anthropogenic disturbances in the riparian forest of Lake Barombi Kotto. The objectives were to determine the tree species composition and diversity in the riparian forest around Lake Barombi Kotto, to elucidate the forest structure and to document the anthropogenic disturbances in this forest. Five plots were laid within which </span><span style="font-family:Verdana;">the </span><span style="font-family:Verdana;">tree enumeration and measurement of dbh were carried out.</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">Trees were identified using scientific identification keys in the Flora of W</span><span style="font-family:Verdana;">est Africa. Disturbance scores were given to each site by qualitatively assessing various disturbances. A total of 340 trees belonging to 70 plant species, 63 genera and 28 plant families were enumerated. Shannon-Wiener diversity varied across sites, with the highest value (H = 3.45) recorded in Tung and the lowest (H = 2.21) in Malenda. Population structure differed across sites,</span><span style="font-family:Verdana;"> the largest stand basal area of 43.78 m</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">/ha was recorded in Bondokombo while the smallest (2.15 m</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">/ha)</span></span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">was recorded in the Sacred Island. </span><i><span style="font-family:Verdana;">Cecropia</span></i></span><i><span style="font-family:""> </span></i><i><span style="font-family:Verdana;">peltata</span></i><span style="font-family:""><span style="font-family:Verdana;"> L., </span><i><span style="font-family:Verdana;">Pseudospondias</span></i></span><i><span style="font-family:""> </span></i><i><span style="font-family:Verdana;">macrocarpa</span></i><i><span style="font-family:""> </span></i><span style="font-family:""><span style="font-family:Verdana;">Oliv. Pierre and </span><i><span style="font-family:Verdana;">Ceiba</span></i></span><i><span style="font-family:""> </span></i><i><span style="font-family:Verdana;">pentandra</span></i><span style="font-family:Verdana;"> (L.) Gaertn had the largest basal areas across the different sites. Species rich families were Malvaceae (9 species), Fabaceae (9 species), Annonaceae</span><span style="font-family:""> </span><span style="font-family:Verdana;">(4 species), and Anacardiaceae (4). This study shows that, there is a high tree species diversity in the protected forest (Tung) but the other unprotected sites are highly disturbed by anthropogenic activities. There is need to develop and enhance existing management policies for this riparian forest, especially by replanting the cut trees and creating a protected riparian buffer to conserve its floristic diversity and ecological functions. 展开更多
关键词 Riparian Forest Tree Dynamics Importance value index Lake Barombi Kotto
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Heating Process of Thermosetting Insulation Materials for Buildings 被引量:1
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作者 孙诗兵 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2012年第5期962-966,共5页
Polyurethane (PU) and phenolic (PF) foams used for building isolation were analyzed by thermal gravity/differential thermal analysis to determine their pyrolysis behavior, including the decomposition point and the... Polyurethane (PU) and phenolic (PF) foams used for building isolation were analyzed by thermal gravity/differential thermal analysis to determine their pyrolysis behavior, including the decomposition point and the maximum reaction rate point. Besides, the shape deformations of PU and PF foams were observed, and their oxygen index and the calorific value in combustion were also studied. The results showed that the pyrolysis of both PU and PF can be divided into three stages from room temperature to 1 000 ℃ in the atmospheric air, with total mass loss of 94.345% for PF and 88.191% for PU, respectively. The oxygen index of PU and PF decreased with increasing the temperature and the duration of the heat treatment. With the temperature increasing, the calorific values of both materials were reduced remarkably. These results of the PU and PF could provide basic data of the thermal stability and fire safety design in the application of thermosetting insulation materials. 展开更多
关键词 polyurethane foam phenolic foam pyrolysis thermo-gravimetry oxygen index calorific value
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Comparative regeneration status in a natural forest and enrichment plantations of Chittagong (south) forest division, Bangladesh
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作者 M. Kamal Hossain M. Lutfor Rahman +1 位作者 A. T. M. Rafiqul Hoque M. Khairul Alam 《Journal of Forestry Research》 SCIE CAS CSCD 2004年第4期255-260,共6页
The natural regeneration of the tree species in pure natural forest stand and enrichment plantations of Baraitali Forest of Chittagong (South) Forest Division, Bangladesh was studied by stratified random quadrat metho... The natural regeneration of the tree species in pure natural forest stand and enrichment plantations of Baraitali Forest of Chittagong (South) Forest Division, Bangladesh was studied by stratified random quadrat method during April 2002 to November 2002. Totally 100 plots of 3 m X 3 m in size represents a total of 64 regenerating tree species from natural forest with an average seedlings of 24767/hm2, while only 40 regenerating tree species were recorded from enrichment plan-tations with an average seedlings of 18633/hm2. Maximum regeneration in natural forest was found with Castanopsis spp. (2200 seedlings/hm2) followed by Glochidion lanceolarium (2183 /hm2) whereas, in enrichment plantations maximum regen-eration was found with Dipterocarpus gracilis (2117/hm2) followed by Anogeissus acuminata (2000/hm2). For natural forest, highest relative density was found for Castanopsis spp (8.88%), relative frequency for Glochidion lanceolarium (7.36%), rela-tive abundance for Syzygium spp. (3.79%) and Importance Value Index were recorded with Glochidion lanceolarium (18.24%). The corresponding values for enrichment plantations were highest with Dipterocarpus gracilis (11.36%), Glochidion lanceo-larium (9.71%), Dipterocarpus gracilis (5.92%), Glochidion lanceolarium (23.32%) respectively. Stem per hectare of some common trees with their seedlings and saplings in both the natural stands and enrichment plantations showed that only Dip-terocarpus gracilis successfully recruited in both sites but recruitment was higher in natural forest. Like many other primary rain forests, the Baraitoli forest typically has both substantial seedlings and soil seed bank from which regeneration may occur. The naturally regenerated seedlings are quite dense but it could not reach the pole stage due to human interference. 展开更多
关键词 REGENERATION Natural forest Enrichment plantations Relative density Frequency ABUNDANCE Importance value index
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Productivity status of traditional agrisilviculture system on northern and southern aspects in mid-hill situation of Garhwal Himalaya, India
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作者 Arvind Bijalwan Chandra Mohan Sharma V. K. Sah 《Journal of Forestry Research》 SCIE CAS CSCD 2009年第2期137-143,I0002,I0003,共9页
The productivity of traditional agrisilviculture system (agricultural crops + trees) was investigated in the northern and south- ern aspects of mid-hill situation in Garhwal Himalaya, Uttarakhand, India during the ... The productivity of traditional agrisilviculture system (agricultural crops + trees) was investigated in the northern and south- ern aspects of mid-hill situation in Garhwal Himalaya, Uttarakhand, India during the 2004-2006. A total of 19 tree species were studied in both northern and southern aspects, out of which 17 tree species were selected in northern aspect and 12 tree species in southern aspect for phytosociological characteristic analysis of trees in agrisilvicultural system. The most dominant tree species are Grewia optiva, Celtis australis and Melia azedarach and successively grown under traditional agrisilviculture system. The results show that the annual produc- tivity of all tree species was 3 775 kg.ha-1.a^-1 in northern aspect (site-N) and 3 10! kg.ha^-1.a^-1 in southern aspect (site-S). G. optiva had the highest productivity in both site-N and site-S among the tree species, followed by M. azedarach, Quercus leucotrichophora and C. australis. The dominant agricultural crops were Eleusine coracana in summer cereals, Phaseolus vulgaris in summer pulses-oilseeds and Triticum aestivum in the winter season in the area. The average biological productivity of agricultural crops in northern aspect was about 16% higher than that in southern aspect under traditional agrisilviculture system. The sole agricultural crop productivity (without trees) in northern aspect was also higher than that in southern aspect. An obvious difference in annual productivity of trees and agriculture crops was observed between northern aspect and southern aspect. The overall productivity in traditional agrisilviculture system (crop + tree) was 24% (in northern aspect) and 21% (in southern aspect) higher than that in sole cropping system. 展开更多
关键词 traditional agrisilviculture system sole agricultural system PRODUCTIVITY PHYTOSOCIOLOGY sole crop importance value index
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Ecological distribution and population structure of Litsea glaucescens(Lauraceae)in the ravines of Sierra Fría and Sierra Laurel,Central Mexico
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作者 Mara Irais FLORES-GALLEGOS Edmundo GARCIA-MOYA +3 位作者 Angelica ROMERO-MANZANARES Mario LUNA-CAVAZOS Martin Alfonso MENDOZA-BRISENO Heike VIBRANS 《Journal of Mountain Science》 SCIE CSCD 2022年第7期1945-1960,共16页
Litsea glaucescens Kunth(Mexican bay leaf,laurel)has a wide distribution in Mexico,growing at both riparian and rupicolous environments in the mountainous region of the Central Highlands of the country.Sierra Frí... Litsea glaucescens Kunth(Mexican bay leaf,laurel)has a wide distribution in Mexico,growing at both riparian and rupicolous environments in the mountainous region of the Central Highlands of the country.Sierra Fría-Sierra Laurel is a protected natural area covered by a dry forest.The Mexican bay leaf is associated with the oak forest,especially on ravines.The species has been considered at risk in recent years.This research is focused on analyzing the elements of the environment of the ravines,which are influencing the distribution and establishment of laurel populations in the region.Two mountainous regions of Aguascalientes were selected,Sierra Fría and Sierra Laurel.Three ravines of the basin were selected to obtain environmental data.Variables registered were topographic,edaphic,and biotic.Principal component analysis was used to identify ecological factors associated with the presence of L.glaucescens.Mexican bay leaf populations were registered in 10 ravines.At the structural level in the community,29 woody species were registered,Mexican bay leaf had an Importance Value Index of 15.8,ranking 10th among all species.Individuals of laurel were classified by size classes(S,individuals with heights ranging from 0 to 20 cm;S,heights ranging from 0.2 to 1.0 m;S,heights between 1 and 2 m with light trace of flowering;S,heights greater than 2 m with flowering greater than 30% of the canopy;and S,individuals with heights greater than 5 m,curved trunk and basal regrowth)to obtain the population structure.The importance index value for all the species in the riparian community was calculated to the community level.Edaphic factors that characterized the presence of Mexican bay leaf were a high percentage of rock coverage(90%),less mulch depth,and sandy loam shallow soils.Sites that showed higher cation exchange capacity had a higher presence of individuals of the S,S,and Ssize classes.Class Sindividuals were found in shady places with 97% of intercepted light.Individuals of classes Sand Sendure less shady places(75%–85% of intercepted light),and individuals class Sand Sare more frequent in open canopies and crag conditions.Regarding the ecological site factors,such as riverside stream,and rocks on mountain slopes,L.glaucescens life form is riparian and rupicolous.Cation exchange capacity,sodium and calcium levels play an important role in the presence of Mexican bay leaf.Distribution on the ravine and recruitment of the Mexican bay leaf populations are associated with shaded sites,mainly for individuals of size classes Sand S,versus sunny places for individuals of size classes Sand S.The overall population structure had a positive kurtosis with all plant size categories well represented;statistically,the population structure of L.glaucescens is very close to the normal distribution.The information obtained allows us to affirm that the laurel populations in the mountainous areas of Sierra Fría and Sierra Laurel from central Mexico are in good demographic condition. 展开更多
关键词 Dry Forest Ephemeral stream Importance value index Mexican bay leaf Population structure Principal Component Analysis
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Vegetation Structure and Regeneration Status of the Western Escarpment of the Rift Valley of the Gamo Zone, Southern Ethiopia
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作者 Temesgen Dingamo Serekebirhan Takele +1 位作者 Zerihun Woldu Sebsebe Demissew 《Open Journal of Ecology》 2022年第1期94-111,共18页
Understanding the structure and regeneration of forest resources contributes to identifying the elements of diversity, endemism, threatened and endangered species. This study was conducted in the western escarpment of... Understanding the structure and regeneration of forest resources contributes to identifying the elements of diversity, endemism, threatened and endangered species. This study was conducted in the western escarpment of the Rift valley of the Gamo Zone, Southern Ethiopia. The main objective was to investigate structure and regeneration status of the study area. A systematic sampling method was used to collect vegetation data from a total 102 quadrats, each 20 × 20 m (400 m<sup>2</sup>) and five 1 × 1 m (1 m<sup>2</sup>) sub-quadrats were established at the four corners and at the centre for sapling and seedling estimation. Tree and shrub species were listed;Height (H ≥ 1.5 m) and DBH ≥ 2 cm were measured and recorded. R-statically software and Microsoft Excel were used to record and analyse the data. A total of 126 plant species belonging to 43 families and 90 genera were identified. The most dominant families were Fabaceae, followed by Anacardiaceae and Euphorbiaceae. Most frequent species were <em>Euclea divinorum </em>(84.3%), followed by <em>Rhus natalensis</em> (83.3%),<em> Terminalia brownii</em> (74.5%). DBH class ≤ 5cm had highest density (63.6%) and DBH ≥ 25.1 cm had the lowest density (0.87%). Three population patterns have been observed;inverted J, J-shaped and irregular shaped. 93% of species had IVI values b/n 1 - 4, 65% of species IVI values < 1% and 7% of species had IVI values ≥ 5.28. <em>Pappea capensis</em>, <em>Combretum molle</em>, <em>Terminalia brownii</em>, <em>Euclea divinorum </em>had highest IVI values. In the vertical stratification, lower story was 91.3% of the individuals. Only a few species contributed to the high density of saplings (440.2/ha) and seedlings (825.49/ha) while most had very little or no saplings and seedlings at all. Thus, in order to revert the current forest structure and regeneration to the previous natural state, it is considered important to minimize the influence of the human interference, grazing and raising awareness to surrounding community. 展开更多
关键词 Importance value index REGENERATION Seedling/Sapling Vegetation Structure
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Assessment of Tree Diversity and Abundance in Rashad Natural Reserved Forest, South Kordofan, Sudan
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作者 Khalid A E Eisawi Hong He +1 位作者 Tayyab Shaheen Emad H. E. Yasin 《Open Journal of Forestry》 2021年第1期37-46,共10页
This study aims to estimate the tree diversity status of Rashad Forest Reserves in the Rashad locality of the South Kordofan State of Sudan. For data collection, eight sample plots (20 × 20</span><b> ... This study aims to estimate the tree diversity status of Rashad Forest Reserves in the Rashad locality of the South Kordofan State of Sudan. For data collection, eight sample plots (20 × 20</span><b> </b><span style="font-family:Verdana;">m) were taken randomly, and parameters were determined: </span><span style="font-family:Verdana;">trees</span><span style="font-family:Verdana;"> species diversity, composition, relative density, dominance, important value index, and species richness in the Rashad forest reserve. The results show that a total of 237 and 56 tree species, including 22 families, have been identified in the study area. Fabaceae family and species numbers have the highest number of 13 species in 8 genera, followed by Combretaceae with 8 species belonging to 3 different genera, Malvaceae with 5 species belonging to 4 different genera, Apocynaceae with 3 species belonging to 3 different genera. The Arecaceae, Burseraceae, Capparaceae, Euphorbiaceae, Meliaceae, and Rubiaceae families each had two species, and all the other 11 families had one species each. Among the 56 different tree species found within the reserve. The results also indicated that </span><i><span style="font-family:Verdana;">Tamarindus indica</span></i><span style="font-family:Verdana;"> L</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">.</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">Ziziphus </span><span style="font-family:Verdana;">spina</span></i><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">christi</span><span style="font-family:Verdana;"> (L.) Desf. had the highest relative density and dominance of 4.64% and 11% respectively. </span><i><span style="font-family:Verdana;">Adansonia digitata</span></i><span style="font-family:Verdana;"> L</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">.</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Grewia </span><span style="font-family:Verdana;">villosa</span></i><span style="font-family:Verdana;"> Willd, </span><i><span style="font-family:Verdana;">Vepris </span><span style="font-family:Verdana;">nobilis</span></i><span style="font-family:Verdana;"> (Delile) Mziray had density and dominance of 4.80% and 9%.</span><b> </b><span style="font-family:Verdana;">Followed by </span><i><span style="font-family:Verdana;">Anogeissus </span><span style="font-family:Verdana;">leiocarpa</span></i><span style="font-family:Verdana;"> (DC.) Guill. & Perr, </span><i><span style="font-family:Verdana;">Adansonia digitata</span></i><span style="font-family:Verdana;"> L</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">.</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Catunaregam </span><span style="font-family:Verdana;">nilotica</span></i><span style="font-family:Verdana;"> (Stapf) Tirveng. (Syn: </span><i><span style="font-family:Verdana;">Xeromphis </span><span style="font-family:Verdana;">nilotica</span></i><span style="font-family:Verdana;"> (Stapf) Keay, </span><i><span style="font-family:Verdana;">Vangueria madagascariensis</span></i><span style="font-family:Verdana;"> J. F. Gmel. with 3.38% and 8%, respectively.</span><b> </b><span style="font-family:Verdana;">Eleven species recorded the least relative dominance of 0.42%.</span><b> </b><span style="font-family:Verdana;">Shannon-Weiner diversity index (H’) value stood at 3.82. And as diversity indices varied with location depending on the species available within an ecological zone, </span><span style="font-family:Verdana;">Rashad</span><span style="font-family:Verdana;"> forest reserve is blessed with a moderate diversity index. 展开更多
关键词 ASSESSMENT Tree Species Diversity Rashad Natural Reserved Forest Relative Density Relative Dominance Importance value index
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Predictive value and impact analysis for the index of microcirculatory resistance in MI patients with elective percutaneous coronary intervention
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作者 王世超 《China Medical Abstracts(Internal Medicine)》 2016年第3期153-154,共2页
Objective To evaluate the predictive value and impact for the index of microcirculatory resistance(IMR)in myocardial infarction(MI)patients with elective percutaneous coronary intervention(PCI)for treating coronary ar... Objective To evaluate the predictive value and impact for the index of microcirculatory resistance(IMR)in myocardial infarction(MI)patients with elective percutaneous coronary intervention(PCI)for treating coronary artery occlusion.Methods A total of 34 patients with STEMI or non-STEMI treated after 12h time window 展开更多
关键词 MI IMR LVEF CRP Predictive value and impact analysis for the index of microcirculatory resistance in MI patients with elective percutaneous coronary intervention PCI
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