We compare Newton’s force law of universal gravitation with a corrected simple approach based on Bhandari’s recently presented work, where the gravitation constant G is maintained. A reciprocity relation exists betw...We compare Newton’s force law of universal gravitation with a corrected simple approach based on Bhandari’s recently presented work, where the gravitation constant G is maintained. A reciprocity relation exists between both alternative gravity formulas with respect to the distances between mass centers. We conclude a one-to-one mapping of the two gravitational formulas. We don’t need Einstein’s construct of spacetime bending by matter.展开更多
The intensive care unit(ICU)is a complex setting by nature,and some have described it as bizarre due to its numerous sirens that sound when anything is dangerous,constant activity,equipment,bright lights,and high fata...The intensive care unit(ICU)is a complex setting by nature,and some have described it as bizarre due to its numerous sirens that sound when anything is dangerous,constant activity,equipment,bright lights,and high fatality rate.The demands placed on nurses to care for critically ill patients in this environment frequently prevent nurses and other health‑care professionals from acknowledging the feelings of patient’s relatives or family caregivers,resulting in a hostile environment from the patient’s relative’s perspective.When a patient’s family enters the ICU,they feel that hospital administrators do little to nothing to alleviate their discomfort and fear.Despite research demonstrating the importance of providing a homely environment for patients’families,In Nigeria ICU is still far behind how a conventional ICU environment should be structured to accommodate patient’s relations in the unit.The goal of this study was to look at the patient’s relative’s perspective on providing care for a critically ill patient in an ICU,with a focus on the unit’s complexity and overall experience.Based on the findings of this study,we recommend that hospital administrators ensure that the environment of the upcoming ICU is designed to meet the needs of patient’s relatives by addressing identified environmental concerns,like caring neglect,by providing a friendly and stress‑free environment.展开更多
Neurodegeneration is one of the biggest public health problems in modern society. Age-associated neurodegeneration, which is accelerated several-fold in Alzheimer＇s disease （AD） alone, is not only an enormous socia...Neurodegeneration is one of the biggest public health problems in modern society. Age-associated neurodegeneration, which is accelerated several-fold in Alzheimer＇s disease （AD） alone, is not only an enormous social and economic burden to the affected in- dividuals and their families, but is also a great scientific challenge. Currently 25-35 million people worldwide suffer from AD, the single largest cause of dementia in middle- to old-aged individuals. These numbers are projected to triple by 2050 if no treatment to prevent or reverse AD is developed.展开更多
AIM：To identify the pathological role of amyloid beta（Aβ） deposition in retinal degeneration,and explore Aβ deposition on the retinal pigment epithelium cells（RPE） layer and the associated structural and functi...AIM：To identify the pathological role of amyloid beta（Aβ） deposition in retinal degeneration,and explore Aβ deposition on the retinal pigment epithelium cells（RPE） layer and the associated structural and functional changes in Alzheimer＇s disease transgenic mice.METHODS：RPE changes in the eyes of APPswe/PS1 transgenic and none transgenic（NTG） mice over 20 months old were examined.Histological changes were investigated via hematoxylin and eosin（H＆E） staining and transmission electron microscopy（TEM） examination,whereas the expression of amyloid precursor protein（APP）,Aβ,Zonula occludens-1（ZO-1） and Ionized calcium binding adaptor molecule-1（IBA-1） were investigated using immunohistochemistry and immunofluorescence techniques.All of the obtained results were quantitatively and statistically analyzed.RESULTS：In aged transgenic mice,an APP-positive immunoreaction and Aβ deposition were detected on the RPE layer but were undetectable in NTG mice.The RPE demonstrated some vacuole changes,shortened basal infoldings and basal deposition in histopathological examination and TEM tests,wherein irregular shapes were indicated by ZO-1 disorganization through fluorescence.Furthermore,IBA-1 positive cells were observed to have accumulated and infiltrated into the RPE layer and localized beneath the RPE/Bruch＇s membrane（Br M） complex,which was accompanied by an increase in BrM thickness in aged transgenic mice in comparison to NTG mice.The IBA-1 positive cells were found to be co-stained with Aβ deposition on the RPE flat mounts.CONCLUSION：The observed Aβ deposition in the RPE layer may cause RPE dysfunction,which is associated with microglia cells infiltration into the retina of aged transgenic mice,suggesting that Aβ deposition probably plays a significant role in RPE-related degenerative disease.展开更多
AIM: To investigate the effect of vitamin D(VD) concentrations and VD supplementation on health related quality of life in inflammatory bowel disease(IBD) patients. METHODS: A cohort of 220 IBD patients including 141 ...AIM: To investigate the effect of vitamin D(VD) concentrations and VD supplementation on health related quality of life in inflammatory bowel disease(IBD) patients. METHODS: A cohort of 220 IBD patients including 141 Crohn's disease(CD) and 79 ulcerative colitis(UC) patients was followed-up at a tertiary IBD center. A subgroup of the cohort(n = 26) took VD supplements for > 3 mo. Health related quality of life was assessed using the short IBD questionnaire(s IBDQ). VD serum concentration and s IBDQ score were assessed between August and October 2012(summer/autumn period) and between February and April 2013(winter/spring period). The mean VD serum concentration and its correlation with disease activity of CD were determined for each season separately. In a subgroup of patients, the effects of VD supplementation on winter VD serum concentration, change in VD serum concentration from summer to winter, and winter s IBDQ score were analyzed.RESULTS: During the summer/autumn and the winter/spring period, 28% and 42% of IBD patients were VD-deficient(< 20 ng/m L), respectively. In the winter/spring period, there was a significant correlation between s IBDQ score and VD serum concentration in UC patients(r = 0.35, P = 0.02), with a trend towards significance in CD patients(r = 0.17, P = 0.06). In the winter/spring period, VD-insufficient patients(< 30 ng/m L) had a significantly lower mean s IBDQ score than VD-sufficient patients; this was true of both UC(48.3 ± 2.3 vs 56.7 ± 3.4, P = 0.04) and CD(55.7 ± 1.25 vs 60.8 ± 2.14, P = 0.04) patients. In all analyzed scenarios(UC/CD, the summer/autumn period and the winter/spring period), health related quality of life was the highest in patients with VD serum concentrations of 50-59 ng/m L. Supplementation with a median of 800 IU/d VD day did not influence VD serum concentration or the s IBDQ score.CONCLUSION: VD serum concentration correlated with health related quality of life in UC and CD patients during the winter/spring period.展开更多
Arctic education refers not only to the teaching,but also to research,communication,dissemination as well as popularization of knowledge related to the Arctic.This article reviews joint efforts between Chinese and Ame...Arctic education refers not only to the teaching,but also to research,communication,dissemination as well as popularization of knowledge related to the Arctic.This article reviews joint efforts between Chinese and American educators and researchers to promote cooperation and understanding in Arctic education and research,and examines the facing challenges of China-U.S.Arctic education cooperation which include current political or economic tensions between the two countries,the differing perspectives and priorities on Arctic policy,the disproportion in Arctic scientific research,different research methodologies and discourse system in social science.This article also argues that there are opportunities for the two countries to cooperate in Arctic education.Common goals and interests in the Arctic,Arctic-dedicated institutions with significant Arctic research capabilities and partnerships around the world provide foundations for Arctic education cooperation.The implementation of a new science-based Arctic treaty of the Arctic Council is an opportunity for China-U.S.Arctic education cooperation.As for future cooperation,it suggests that in addition to promoting the direct bilateral cooperation,cooperation within international cooperation platforms and mechanisms,especially within the Arctic Council also needs to be further promoted.展开更多
In this article we explored the crystal structure of a few pearls and shellfish's shell of fresh water and sea water, and found that pearls and nacreous layer (perhaps and prismatic layer) of shells are all the sa...In this article we explored the crystal structure of a few pearls and shellfish's shell of fresh water and sea water, and found that pearls and nacreous layer (perhaps and prismatic layer) of shells are all the same: CaCO3, orthorhombic system, aragonite structure and the value of lattice spacings are almost identical. This shows that the pearls of fresh water and sea water are all the same in nature.展开更多
Time:December 8-11,2013Venue:Palexpo Geneva Congress Center,Geneva,Switzerland Email:Parkinson@kenes.com Website:www2.kenes.com/parkinson/Pages/Home.aspxⅩⅩ World Congress on Parkinson’s Disease and Related Disorder...Time:December 8-11,2013Venue:Palexpo Geneva Congress Center,Geneva,Switzerland Email:Parkinson@kenes.com Website:www2.kenes.com/parkinson/Pages/Home.aspxⅩⅩ World Congress on Parkinson’s Disease and Related Disorders will be held on December 8-11,2013 in Geneva,Switzerland.As the motto for this World Congress is'Integration by Translation',this Congress will deal in a most translational way with most recent research and updates on the etiology,pathogenesis,potential diagnostic markers and treatment modalities展开更多
The Chinese Journal of Alzheimer’s Disease&Related Disorders, the first journal dedicated to Alzheimer’s disease and related neurodegenerative diseases in China, was founded by Chinese Association for Alzheimer...The Chinese Journal of Alzheimer’s Disease&Related Disorders, the first journal dedicated to Alzheimer’s disease and related neurodegenerative diseases in China, was founded by Chinese Association for Alzheimer’s disease (CAAD)(CN 10-1536/R, ISSN 2096—5516) in early 2018.展开更多
China has many lakes, marshlands and rivers. Due to their uneven geographical distribution and varied degrees of salinity, their exploitable freshwater resources are limited. In the wake of the highspeed growth of nat...China has many lakes, marshlands and rivers. Due to their uneven geographical distribution and varied degrees of salinity, their exploitable freshwater resources are limited. In the wake of the highspeed growth of national economy in recent years, human infringement upon their natural settings has been increasingly intense, leading to the degeneration of China's lacustrine ecosystems and the degradation of their surrounding environments. Lakes are shrinking and becoming more saline. In arid and semi-arid inland areas, some of them have even disappeared. In addition, lake water pollution and eutrophication in densely populated areas are getting worse, resulting in serious water shortages in some places. Silt deposition in lake basins, water surface shrinkage caused by hectic and irrational reclamation for farmland, the prevalence of flooding and water-logging calamities and ecosystem depletion caused by predatory exploitation of fishery resources, all of these have become restrictive factors in regional sustainable development. The author of this article suggests measures for the protection and sustainable exploitation of limnetic settings in China.展开更多
Due to global climate warming and natural and man-made land subsidence etc., relative sea level rise in the coastal plains of China will exceed 2-3 times over the golbal mean value during the first half part of the 21...Due to global climate warming and natural and man-made land subsidence etc., relative sea level rise in the coastal plains of China will exceed 2-3 times over the golbal mean value during the first half part of the 21st century. It will result in a series of adverse impacts on evolution of natural environment and socioeconomic development of the coastal area. This paper analyses environmental and resource effects induced by relative sea level rise in China's coastal areas on the basis of rough estimate of future relative sea level rise. These effects include inundating tidal flat and wetlands and increase in inundated risk of coastal habitable land,exacerbating storm surge. coastal erosion, flooding and salt water intrusion hazards.as well as endangering land. water. tourism and living resources and their utilization.展开更多
The Lie symmetry and Hojman conserved quantity of Nielsen equations in a dynamical system of relative motion with nonholonomic constraint of the Chetaev type are studied. The differential equations of motion of the Ni...The Lie symmetry and Hojman conserved quantity of Nielsen equations in a dynamical system of relative motion with nonholonomic constraint of the Chetaev type are studied. The differential equations of motion of the Nielsen equation for the system, the definition and the criterion of Lie symmetry, and the expression of the Hojman conserved quantity deduced directly from the Lie symmetry for the system are obtained. An example is given to illustrate the application of the results.展开更多
This paper presents an investigation of a DC glow discharge at low pressure in the normal mode and with Einstein＇s relation of electron diffusivity. Two-dimensional distributions in Cartesian geometry are presented i...This paper presents an investigation of a DC glow discharge at low pressure in the normal mode and with Einstein＇s relation of electron diffusivity. Two-dimensional distributions in Cartesian geometry are presented in the stationary state, including electric potential, electron and ion densities, longitudinal and transverse electrics fields as well as electron temperature. Our results are compared with those obtained in existing literature. The model used in this work is based on the first three moments of Boltzmann＇s equation. They serve as the continuity equation, the momentum transfer and the energy equations. The set of equations for charged particles presented in monatomic argon gas are coupled in a self-consistent way with Poisson＇s equation. A parametric study varying the cathode voltage, gas pressure, and secondary electron emission coefficient predicts many of the well-known features of DC discharges.展开更多
The most commonly used method for assessing the hydraulic erodibility of rock is Annandale's method.This method is based on a correlation between the erosive force of flowing water and the capacity of rock resista...The most commonly used method for assessing the hydraulic erodibility of rock is Annandale's method.This method is based on a correlation between the erosive force of flowing water and the capacity of rock resistance. This capacity is evaluated using Kirsten's index, which was initially developed to evaluate the excavatability of earth materials. For rocky material, this index is determined according to certain geomechanical factors related to intact rock and rock mass, such as compressive strength of intact rock, rock block size, discontinuity shear strength and relative block structure. To quantify the relative block structure, Kirsten(1982) developed a mathematical expression that accounts for the shape and orientation of the blocks relative to the direction of flow. Kirsten's initial concept for assessing the relative block structure considers that the geological formation is mainly fractured by two joint sets forming an orthogonally fractured system. An adjusted concept is proposed to determine the relative block structure when the fractured system is non-orthogonal where the angle between the planes of the two joint sets is greater or less than 90°. An analysis of the proposed relative block structure rating shows that considering a non-orthogonally fractured system has a significant effect on Kirsten's index and, as a consequence, on the assessment of the hydraulic erodibility of rock.展开更多
文摘We compare Newton’s force law of universal gravitation with a corrected simple approach based on Bhandari’s recently presented work, where the gravitation constant G is maintained. A reciprocity relation exists between both alternative gravity formulas with respect to the distances between mass centers. We conclude a one-to-one mapping of the two gravitational formulas. We don’t need Einstein’s construct of spacetime bending by matter.
文摘The intensive care unit(ICU)is a complex setting by nature,and some have described it as bizarre due to its numerous sirens that sound when anything is dangerous,constant activity,equipment,bright lights,and high fatality rate.The demands placed on nurses to care for critically ill patients in this environment frequently prevent nurses and other health‑care professionals from acknowledging the feelings of patient’s relatives or family caregivers,resulting in a hostile environment from the patient’s relative’s perspective.When a patient’s family enters the ICU,they feel that hospital administrators do little to nothing to alleviate their discomfort and fear.Despite research demonstrating the importance of providing a homely environment for patients’families,In Nigeria ICU is still far behind how a conventional ICU environment should be structured to accommodate patient’s relations in the unit.The goal of this study was to look at the patient’s relative’s perspective on providing care for a critically ill patient in an ICU,with a focus on the unit’s complexity and overall experience.Based on the findings of this study,we recommend that hospital administrators ensure that the environment of the upcoming ICU is designed to meet the needs of patient’s relatives by addressing identified environmental concerns,like caring neglect,by providing a friendly and stress‑free environment.
基金supported in part by the New York State Office of People with Developmental Disabilities(OPWDD)Zenith Award ZEN-12-241233 from Alzheimer’s Associationa research grant#20121203 from Alzheimer’s Drug Discovery Foundation,New York
文摘Neurodegeneration is one of the biggest public health problems in modern society. Age-associated neurodegeneration, which is accelerated several-fold in Alzheimer＇s disease （AD） alone, is not only an enormous social and economic burden to the affected in- dividuals and their families, but is also a great scientific challenge. Currently 25-35 million people worldwide suffer from AD, the single largest cause of dementia in middle- to old-aged individuals. These numbers are projected to triple by 2050 if no treatment to prevent or reverse AD is developed.
基金Supported by the National Natural Science Foundation of China(No.81430009No.81400424)the Science and Technology Research and Development Project of Shaanxi Province(No.2014K11-03-07-04)
文摘AIM：To identify the pathological role of amyloid beta（Aβ） deposition in retinal degeneration,and explore Aβ deposition on the retinal pigment epithelium cells（RPE） layer and the associated structural and functional changes in Alzheimer＇s disease transgenic mice.METHODS：RPE changes in the eyes of APPswe/PS1 transgenic and none transgenic（NTG） mice over 20 months old were examined.Histological changes were investigated via hematoxylin and eosin（H＆E） staining and transmission electron microscopy（TEM） examination,whereas the expression of amyloid precursor protein（APP）,Aβ,Zonula occludens-1（ZO-1） and Ionized calcium binding adaptor molecule-1（IBA-1） were investigated using immunohistochemistry and immunofluorescence techniques.All of the obtained results were quantitatively and statistically analyzed.RESULTS：In aged transgenic mice,an APP-positive immunoreaction and Aβ deposition were detected on the RPE layer but were undetectable in NTG mice.The RPE demonstrated some vacuole changes,shortened basal infoldings and basal deposition in histopathological examination and TEM tests,wherein irregular shapes were indicated by ZO-1 disorganization through fluorescence.Furthermore,IBA-1 positive cells were observed to have accumulated and infiltrated into the RPE layer and localized beneath the RPE/Bruch＇s membrane（Br M） complex,which was accompanied by an increase in BrM thickness in aged transgenic mice in comparison to NTG mice.The IBA-1 positive cells were found to be co-stained with Aβ deposition on the RPE flat mounts.CONCLUSION：The observed Aβ deposition in the RPE layer may cause RPE dysfunction,which is associated with microglia cells infiltration into the retina of aged transgenic mice,suggesting that Aβ deposition probably plays a significant role in RPE-related degenerative disease.
基金Supported by Grant from the Slovak APVV agency,No.APVV-0672-11
文摘AIM: To investigate the effect of vitamin D(VD) concentrations and VD supplementation on health related quality of life in inflammatory bowel disease(IBD) patients. METHODS: A cohort of 220 IBD patients including 141 Crohn's disease(CD) and 79 ulcerative colitis(UC) patients was followed-up at a tertiary IBD center. A subgroup of the cohort(n = 26) took VD supplements for > 3 mo. Health related quality of life was assessed using the short IBD questionnaire(s IBDQ). VD serum concentration and s IBDQ score were assessed between August and October 2012(summer/autumn period) and between February and April 2013(winter/spring period). The mean VD serum concentration and its correlation with disease activity of CD were determined for each season separately. In a subgroup of patients, the effects of VD supplementation on winter VD serum concentration, change in VD serum concentration from summer to winter, and winter s IBDQ score were analyzed.RESULTS: During the summer/autumn and the winter/spring period, 28% and 42% of IBD patients were VD-deficient(< 20 ng/m L), respectively. In the winter/spring period, there was a significant correlation between s IBDQ score and VD serum concentration in UC patients(r = 0.35, P = 0.02), with a trend towards significance in CD patients(r = 0.17, P = 0.06). In the winter/spring period, VD-insufficient patients(< 30 ng/m L) had a significantly lower mean s IBDQ score than VD-sufficient patients; this was true of both UC(48.3 ± 2.3 vs 56.7 ± 3.4, P = 0.04) and CD(55.7 ± 1.25 vs 60.8 ± 2.14, P = 0.04) patients. In all analyzed scenarios(UC/CD, the summer/autumn period and the winter/spring period), health related quality of life was the highest in patients with VD serum concentrations of 50-59 ng/m L. Supplementation with a median of 800 IU/d VD day did not influence VD serum concentration or the s IBDQ score.CONCLUSION: VD serum concentration correlated with health related quality of life in UC and CD patients during the winter/spring period.
基金supported by the 2021 Youth Research Fund Project“Research on Legal Issues of Protection of China’s Rights and Interests in the Antarctic under the Background of Momentous Changes of a Like Not Seen in a Century”of Shanghai University of Political Science and Law(Grant no.2021XQN27)the 2020 Research Fund Project“Indian Polar Policy Research”of China National Institute for SCO International Exchange and Judicial Cooperation(Grant no.20SHJD027)the China Association of Marine Affairs(CAMA)Project“Key Issues in the Exploitation and Utilization of Polar Biological Resources under the New Situation”(Grant no.CODF-AOC202301).
文摘Arctic education refers not only to the teaching,but also to research,communication,dissemination as well as popularization of knowledge related to the Arctic.This article reviews joint efforts between Chinese and American educators and researchers to promote cooperation and understanding in Arctic education and research,and examines the facing challenges of China-U.S.Arctic education cooperation which include current political or economic tensions between the two countries,the differing perspectives and priorities on Arctic policy,the disproportion in Arctic scientific research,different research methodologies and discourse system in social science.This article also argues that there are opportunities for the two countries to cooperate in Arctic education.Common goals and interests in the Arctic,Arctic-dedicated institutions with significant Arctic research capabilities and partnerships around the world provide foundations for Arctic education cooperation.The implementation of a new science-based Arctic treaty of the Arctic Council is an opportunity for China-U.S.Arctic education cooperation.As for future cooperation,it suggests that in addition to promoting the direct bilateral cooperation,cooperation within international cooperation platforms and mechanisms,especially within the Arctic Council also needs to be further promoted.
基金The project supported by National Natural Science Foundation of China(NSFC)
文摘In this article we explored the crystal structure of a few pearls and shellfish's shell of fresh water and sea water, and found that pearls and nacreous layer (perhaps and prismatic layer) of shells are all the same: CaCO3, orthorhombic system, aragonite structure and the value of lattice spacings are almost identical. This shows that the pearls of fresh water and sea water are all the same in nature.
文摘Time:December 8-11,2013Venue:Palexpo Geneva Congress Center,Geneva,Switzerland Email:Parkinson@kenes.com Website:www2.kenes.com/parkinson/Pages/Home.aspxⅩⅩ World Congress on Parkinson’s Disease and Related Disorders will be held on December 8-11,2013 in Geneva,Switzerland.As the motto for this World Congress is'Integration by Translation',this Congress will deal in a most translational way with most recent research and updates on the etiology,pathogenesis,potential diagnostic markers and treatment modalities
文摘The Chinese Journal of Alzheimer’s Disease&Related Disorders, the first journal dedicated to Alzheimer’s disease and related neurodegenerative diseases in China, was founded by Chinese Association for Alzheimer’s disease (CAAD)(CN 10-1536/R, ISSN 2096—5516) in early 2018.
文摘China has many lakes, marshlands and rivers. Due to their uneven geographical distribution and varied degrees of salinity, their exploitable freshwater resources are limited. In the wake of the highspeed growth of national economy in recent years, human infringement upon their natural settings has been increasingly intense, leading to the degeneration of China's lacustrine ecosystems and the degradation of their surrounding environments. Lakes are shrinking and becoming more saline. In arid and semi-arid inland areas, some of them have even disappeared. In addition, lake water pollution and eutrophication in densely populated areas are getting worse, resulting in serious water shortages in some places. Silt deposition in lake basins, water surface shrinkage caused by hectic and irrational reclamation for farmland, the prevalence of flooding and water-logging calamities and ecosystem depletion caused by predatory exploitation of fishery resources, all of these have become restrictive factors in regional sustainable development. The author of this article suggests measures for the protection and sustainable exploitation of limnetic settings in China.
文摘Due to global climate warming and natural and man-made land subsidence etc., relative sea level rise in the coastal plains of China will exceed 2-3 times over the golbal mean value during the first half part of the 21st century. It will result in a series of adverse impacts on evolution of natural environment and socioeconomic development of the coastal area. This paper analyses environmental and resource effects induced by relative sea level rise in China's coastal areas on the basis of rough estimate of future relative sea level rise. These effects include inundating tidal flat and wetlands and increase in inundated risk of coastal habitable land,exacerbating storm surge. coastal erosion, flooding and salt water intrusion hazards.as well as endangering land. water. tourism and living resources and their utilization.
文摘The Lie symmetry and Hojman conserved quantity of Nielsen equations in a dynamical system of relative motion with nonholonomic constraint of the Chetaev type are studied. The differential equations of motion of the Nielsen equation for the system, the definition and the criterion of Lie symmetry, and the expression of the Hojman conserved quantity deduced directly from the Lie symmetry for the system are obtained. An example is given to illustrate the application of the results.
文摘This paper presents an investigation of a DC glow discharge at low pressure in the normal mode and with Einstein＇s relation of electron diffusivity. Two-dimensional distributions in Cartesian geometry are presented in the stationary state, including electric potential, electron and ion densities, longitudinal and transverse electrics fields as well as electron temperature. Our results are compared with those obtained in existing literature. The model used in this work is based on the first three moments of Boltzmann＇s equation. They serve as the continuity equation, the momentum transfer and the energy equations. The set of equations for charged particles presented in monatomic argon gas are coupled in a self-consistent way with Poisson＇s equation. A parametric study varying the cathode voltage, gas pressure, and secondary electron emission coefficient predicts many of the well-known features of DC discharges.
基金the organizations that have funded this project:the Natural Sciences and Engineering Research Council of Canada(Grant No.498020-16)Hydro-Quebec(NC-525700)Mitacs Accelerate Program(Grant Ref.IT10008)
文摘The most commonly used method for assessing the hydraulic erodibility of rock is Annandale's method.This method is based on a correlation between the erosive force of flowing water and the capacity of rock resistance. This capacity is evaluated using Kirsten's index, which was initially developed to evaluate the excavatability of earth materials. For rocky material, this index is determined according to certain geomechanical factors related to intact rock and rock mass, such as compressive strength of intact rock, rock block size, discontinuity shear strength and relative block structure. To quantify the relative block structure, Kirsten(1982) developed a mathematical expression that accounts for the shape and orientation of the blocks relative to the direction of flow. Kirsten's initial concept for assessing the relative block structure considers that the geological formation is mainly fractured by two joint sets forming an orthogonally fractured system. An adjusted concept is proposed to determine the relative block structure when the fractured system is non-orthogonal where the angle between the planes of the two joint sets is greater or less than 90°. An analysis of the proposed relative block structure rating shows that considering a non-orthogonally fractured system has a significant effect on Kirsten's index and, as a consequence, on the assessment of the hydraulic erodibility of rock.
