Paired stable oxygen isotope and Mg/Ca analyses in calcite tests of the mixed-layer-dwelling planktic foraminifer Globigerinoides ruber has been used to reconstruct equatorial Indian Oceanδ18O of seawater (δ 18Osw ...Paired stable oxygen isotope and Mg/Ca analyses in calcite tests of the mixed-layer-dwelling planktic foraminifer Globigerinoides ruber has been used to reconstruct equatorial Indian Oceanδ18O of seawater (δ 18Osw ) over the last ~137 thousand years. On the basis of ice-volume-correctedδ18Osw (δ18Osw-ivc ), relative changes in sea surface salinity (SSS) have been estimated. The SSS estimates suggest three episodes of higher SSS (131-113 thousand years before present (kyr BP), 62-58 kyr BP, and 30-24 kyr BP) within the last glacial period as compared with the present. SSS comparison between interglacial episodes reveals that the surface seawater over the core site was significantly saltier during the penultimate interglacial than the Holocene. We suggest that the evolution of a seasonal insolation gradient between the Indian monsoon areas and the equator over the investigated time interval was instrumental in shaping the strength of the Indian winter and summer monsoons that left their imprints on the equatorial Indian Ocean SSS via freshwater input and wind-induced mixing. The study shows that the insolation difference between northern latitudes and the equator during winter affects monsoon strength in the Indian region, especially during cold intervals.展开更多
This paper describes a novel approach in developing a model for forecasting of global insolation on a horizontal plane.In the proposed forecasting model,constraints,such as latitude and whole precipitable water conten...This paper describes a novel approach in developing a model for forecasting of global insolation on a horizontal plane.In the proposed forecasting model,constraints,such as latitude and whole precipitable water content in vertical column of that location,are used.These parameters can be easily measurable with a global positioning system(GPS).The earlier model was developed by using the above datasets generated from different locations in India.The model has been verified by calculating theoretical global insolation for different sites covering east,west,north,south and the central region with the measured values from the same locations.The model has also been validated on a region,from which data was not used during the development of the model.In the model,clearness index coefficients(KT)are updated using the ensemble Kalman filter(EnKF)algorithm.The forecasting efficacies using the KT model and EnKF algorithm have also been verified by comparing two popular algorithms,namely the recursive least square(RLS)and Kalman filter(KF)algorithms.The minimum mean absolute percentage error(MAPE),mean square error(MSE)and correlation coefficient(R)value obtained in global solar insolation estimations using EnKF in one of the locations are 2.4%,0.0285 and 0.9866 respectively.展开更多
The paper identifies and analyzes the geographical and temporal variability of solar energy in Kuwait. The fundamental solar trigonometric model has been modified to estimate daily and hourly solar radiation on horizo...The paper identifies and analyzes the geographical and temporal variability of solar energy in Kuwait. The fundamental solar trigonometric model has been modified to estimate daily and hourly solar radiation on horizontal surfaces on the basis of the more readily available meteorological data. The results demonstrate that Kuwait has an abundance of solar energy capability. An overview of the production and consumption of electrical energy, installed capacity, and peak loads in Kuwait is also presented. Finally, it is shown how the power produced from the photovoitaic (PV) cells depends on the solar radiation. The proposed PV module is made up of a combination of series and parallel cells to increase power, while the IoV characteristic and output power of the module each month may be obtained from the model.展开更多
During a research cruise over the Pacific Ocean in 1989, solar irradiance was measured with a broad-band pyranometer along the cruise track. Cloud cover was photographed with an all-sky time-lapse came ra. Cloud types...During a research cruise over the Pacific Ocean in 1989, solar irradiance was measured with a broad-band pyranometer along the cruise track. Cloud cover was photographed with an all-sky time-lapse came ra. Cloud types were observed and recorded. The data show that both the types and the amounts of clouds affect radiation fluxes on the sea surface. For low-level and middle-level clouds, the correlations (r) between measured irradiance (in Percent of calculated maximum irradiance) and cloud amount (in fraction of sky) were significant: r=-0. 79 and - 0. 66, respectively. For high-level clouds, the correlation was not significant: r=-0. 21. The results indicate that cloud shortwave forcing is a major modifier of the earth's surface insolation and change of cloud amount may affect global climate.展开更多
From 1950 to 1987 a strong relationship existed between the El Nino-Southern Oscillation (ENSO) and HadCRUT4 global average temperature anomaly, interrupted occasionally by volcanic erup-tions. After 1987 the relation...From 1950 to 1987 a strong relationship existed between the El Nino-Southern Oscillation (ENSO) and HadCRUT4 global average temperature anomaly, interrupted occasionally by volcanic erup-tions. After 1987 the relationship diverged, with temperature anomaly increasing more than ex-pected, but was re-established after 1997 at an offset of ~0.48°C higher. The period of increased warming from 1987 to 1997 loosely coincided with the divergence of the global average tempera-ture anomalies over land, which are derived from observation station recordings, and the global average anomalies in sea surface temperatures. Land-based temperatures averaged 0.04°C below sea temperatures for the period 1950 to 1987 but after 1997 averaged 0.41°C above sea tempera-tures. The increase in the global average temperature anomaly and the divergence of land and sea surface temperatures also coincided with two significant changes in global average cloud cover. Total cloud cover decreased during the period from 1987 to 1997 and, for most of the remainder of the period from 1984 to 2009, decreases in low-level cloud were accompanied by increases in middle and upper level cloud. These changes can be found in both global average cloud cover and in each of the six 30°C-latitude bands. The impact of these changes in cloud cover can account for the variations in HadCRUT4 global average temperature anomalies and the divergence between land and sea temperatures.展开更多
The astronomical theory of climate change is based on the solution of differential equations describing Earth’s orbital and rotational motions. The equations are used to calculate the change in insolation over the Ea...The astronomical theory of climate change is based on the solution of differential equations describing Earth’s orbital and rotational motions. The equations are used to calculate the change in insolation over the Earth’s surface. As a result of the author’s solution of the orbital problem, the periods and amplitudes of Earth-orbit variations and their evolution have been refined. Unlike previous studies, the equations of Earth’s rotational motion are solved completely. The Earth’s rotational axis precesses relative to a direction different from the direction of the orbit’s axial precession, and oscillates with periods of half a month, half a year and 18.6 years. Also, its oscillations occur with irregular periods of several tens of thousands of years and more. All these motions lead to oscillations of the obliquity in the range of 14.7° to 32.1°, which prove to be 7 - 8 times larger than obtained by a previous theory. In the same proportion, the Earth’s insolation oscillations increase in amplitude, with insolation extremes occurring in other epochs than those in the previous theory. The amplitudes and the onset times of the extremes correlate with known paleoclimate changes. Thirteen insolation periods of paleoclimate variation over an interval of 200 thousand years are identified. From the insolation evolution calculated over a time interval of 1 million years, 6 climate gradations from very cold to very warm are identified.展开更多
Building envelope is a fence that controls heat exchange between interior and exterior and plays an essential role in providing thermal comfort conditions of residents. In recent years, due to the necessity of conserv...Building envelope is a fence that controls heat exchange between interior and exterior and plays an essential role in providing thermal comfort conditions of residents. In recent years, due to the necessity of conserving energy and also preventing increased environmental pollution, the importance of sustainable construction has been doubled. Checking the problems of thermal behavior of the building envelope materials, and what influences in the heating and cooling loads exerted and energy consumption of buildings, are the questions that this research seeks to answer. In this regard, building information modelling analysis (BIM) has worthy contribution in the completion process of sustainable design;thus using software Design Builder, it is paid attention to simulation of the thermal behavior of two types of defined materials for the building envelope that was designed as a Research Institute of Renewable Energy of Yazd University. For Type 1 materials, two layers of brick have been selected, and for Type 2 a thermal insulation layer also added it. Results of the analysis showed that the use of materials Type 2 in the cooling load %4.8 and in the thermal load %62.5 reduction can be achieved which means reducing the load on active system and thus reducing the initial cost of building. Also reduction in annual energy consumption by almost %2.4 for cooling and %62.9 for heating buildings have been achieved, which makes saving non-renewable energy consumption, and consequently reducing environmental pollution as well as reducing current costs will be established.展开更多
Flexible,compact,lightweight and sustainable power sources are indispensable for modern wearable and personal electronics and small-unmanned aerial vehicles(UAVs).Hierarchical honeycomb has the unique merits of compac...Flexible,compact,lightweight and sustainable power sources are indispensable for modern wearable and personal electronics and small-unmanned aerial vehicles(UAVs).Hierarchical honeycomb has the unique merits of compact mesostructures,excellent energy absorption properties and considerable weight to strength ratios.Herein,a honeycomb-inspired triboelectric nanogenerator(h-TENG)is proposed for biomechanical and UAV morphing wing energy harvesting based on contact triboelectrification wavy surface of cellular honeycomb structure.The wavy surface comprises a multilayered thin film structure(combining polyethylene terephthalate,silver nanowires and fluorinated ethylene propylene)fabricated through high-temperature thermoplastic molding and wafer-level bonding process.With superior synchronization of large amounts of energy generation units with honeycomb cells,the manufactured h-TENG prototype produces the maximum instantaneous open-circuit voltage,short-circuit current and output power of 1207 V,68.5μA and 12.4 mW,respectively,corresponding to a remarkable peak power density of 0.275 mW cm^(−3)(or 2.48 mW g^(−1))under hand pressing excitations.Attributed to the excellent elastic property of self-rebounding honeycomb structure,the flexible and transparent h-TENG can be easily pressed,bent and integrated into shoes for real-time insole plantar pressure mapping.The lightweight and compact h-TENG is further installed into a morphing wing of small UAVs for efficiently converting the flapping energy of ailerons into electricity for the first time.This research demonstrates this new conceptualizing single h-TENG device’s versatility and viability for broad-range real-world application scenarios.展开更多
Objective:To investigate the effectiveness of molding custom-made insoles for female patients with foot pain.Methods:The study included 20 patients whose insoles were prescribed according to biomechanical evaluations ...Objective:To investigate the effectiveness of molding custom-made insoles for female patients with foot pain.Methods:The study included 20 patients whose insoles were prescribed according to biomechanical evaluations and molded by repositioning the subtalar joint in its neutral position using a simple set of tools.展开更多
Objectives. The aim of this study was to investigate the effects of orthopaedic soles on the body posture. Methods. Forty-eight runners (21 men and 28 women) maintained a standing-up position on both feet with bare fe...Objectives. The aim of this study was to investigate the effects of orthopaedic soles on the body posture. Methods. Forty-eight runners (21 men and 28 women) maintained a standing-up position on both feet with bare feet with neutral soles and orthopedic soles which contained bilaterally a podiatrist element of 3 mm height behind the metatarsal heads (Metatarsal Retro Capital Bar, MRCB). Stabilometric, plantar pressure and kinematic data in the sagittal plane on both sides were measured at 40 and 60 Hz, respectively. The position of the center of pressure on the anteroposterior axis (YCoP), the forefoot plantar pressure (FPP) and the anteroposterior position of the knee (Yk), the hip (YH), the shoulder (YS) and the ears (YE) with respect to the vertical axis passing through the joint of the ankle were determined for each experimental condition. Findings. The addition of a MRCB orthopedic element induced in backward displacement of CoP, hip, shoulder and ears (p CoP and FPP changes were significantly correlated with YH, YS and YE changes (p Conclusion. These results suggest that the addition of an orthopedic element located behind the metatarsal heads influences the overall position of the body and can help podiatrist in the care of their patients.展开更多
Fall has become the second leading cause of unintentional injury, death, after road traffic injuries, for the elderly in Europe. This proportion will increase in the next decades and become more than ever a real publi...Fall has become the second leading cause of unintentional injury, death, after road traffic injuries, for the elderly in Europe. This proportion will increase in the next decades and become more than ever a real public health issue. France was selected by the World Health Organization to be the first country to implement a program that reduces the coverage of the dependence. Commercial automatic fall detection devices can help seniors get back on their feet faster by reducing the time of emergency procedure. Many seniors do not take advantage of this potentially life-saving technology mainly because of intrusiveness constraints. After having reminded the context and the challenges of fall detection systems, this paper presents an original device which is unobtrusive, comfortable and very effective. The hardware architecture embedded into the sole and a new fall detection algorithm based on acceleration and time thresholds are presented. The algorithm introduces a new concept of differential acceleration to eliminate some drawbacks of current systems. Tests were carried out under real life conditions by 6 young participants for different ADLs. The data were analyzed blindly. We compared the detected falls and found a 100% sensibility and more than 93% sensitivity for all participants and scenarios.展开更多
Objectives: We evaluated whether a valgus knee brace and an insole with subtalar strapping could reduce pain and improve functional scores over 12 months in patients with medial knee osteoarthritis (OA). Methods: OA w...Objectives: We evaluated whether a valgus knee brace and an insole with subtalar strapping could reduce pain and improve functional scores over 12 months in patients with medial knee osteoarthritis (OA). Methods: OA was confirmed by radiography in all patients, who were divided into three groups: exercise (n = 44), insole (n = 55), and brace (n = 19). Clinical knee functions and gait analyses were evaluated. Results: After 12 months, the clinical results for all groups had improved compared to pretreatment findings. Although the knee varus moment decreased and the gait speed increased when the insole was worn initially, the effects of the insole decreased at 6 and 12 months. In contrast, the knee varus moment decreased and the gait speed increased when the brace was initially fitted. The effects of the brace were maintained during the 12 months. Conclusions: The insole was effective for patients with Kellgren-Lawrence Grades II and III, and the knee brace was effective for patients with Grades III and IV conditions. Furthermore, the knee brace was more effective when worn for more than 6 months, while the effects of the insoles were not continuous.展开更多
The main objective of this work is to develop a technological solution to support active aging of frail older individuals. In this perspective, we designed a connected insole in order to encourage frail elderly person...The main objective of this work is to develop a technological solution to support active aging of frail older individuals. In this perspective, we designed a connected insole in order to encourage frail elderly persons to become more active in their daily life. The project presented in this paper, funded by the French National Research Agency, aims to design and evaluate an original solution to follow and encourage walking activity. The evaluation is performed in two stages: adjusting tests in a living-lab with nine healthy elderly, then clinical evaluation of three frail patients followed over one month. We designed a noninvasive wireless insole, which automatically measures gait parameters and transmits information to a remote terminal via a secure Internet connection. The first laboratory tests of this technological solution showed good reliability measurements as well as good user acceptability. The average distance error obtained on volunteers is 3.2% and the accuracy of the average walking speed is 96.8% thanks to design of a calibration system based on a personalized stride length measurement. Finally, the introduction of an induction charging instead of a button cell makes the system perfectly autonomous. In this paper, we present the specifications of the solution, the design of the connected insole, the methods used to measure desired parameters, the results of the living-lab tests, and the work in progress.展开更多
An insole design with variable stiffness properties could be an effective conservative treatment option for knee osteoarthritis (OA). However, limited to the experimental conditions, stress distribution inside the car...An insole design with variable stiffness properties could be an effective conservative treatment option for knee osteoarthritis (OA). However, limited to the experimental conditions, stress distribution inside the cartilage of a knee joint is often difficult to be obtained. In this study, a finite element (FE)- based computational model of the human knee-foot-ankle complex is presented to investigate the redistribution of the internal stress of the knee joint using a variable stiffness insole. Based on relationship between the insole parameters and the resulting tissue stress data, additive manufacture technology (AM) could be a fast deliver of an optimal insole that meets patient characteristics. Insoles of four different material combinations were designed. Von-Mises stress declined significantly at the meniscus when the ratio of the lateral and medial stiffness of the insole changes. It suggests that the intervention of variable stiffness insole contributes to the rehabilitation of medial knee osteoarthritis (OA) and provide the guidance for the design of therapeutic insole.展开更多
In the north-eastern Qinghai-Tibet Plateau(QTP),the source area of the Yellow River(SAYR)has been experiencing significant changes in climatic and environmental conditions in recent decades.To date,few studies have co...In the north-eastern Qinghai-Tibet Plateau(QTP),the source area of the Yellow River(SAYR)has been experiencing significant changes in climatic and environmental conditions in recent decades.To date,few studies have combined modern hydrological conditions with paleoclimate records to explore the mechanism(s)of these changes.This study seeks to improve understanding of hydrological variability on decadal and centennial timescales in the SAYR and to identify its general cause.We first determined annual fluctuations in the surface area of Lake Ngoring from 1985 to 2020 using multi-temporal Landsat images.The results show that lake surface area changes were generally consistent with variations in precipitation,streamflow and the regional dry-wet index in the SAYR,suggesting that the water balance of the Lake Ngoring area is closely associated with regional hydroclimate changes.These records are also comparable to the stalagmite δ^(18)O monsoon record,as well fluctuations in the Southern Oscillation Index(SOI).Moreover,an association of high TSI(total solar insolation)anomalies and sunspot numbers with the expansion of Lake Ngoring surface area is observed,implying that solar activity is the key driving factor for hydrologic variability in the SAYR on a decadal timescale.Following this line of reasoning,we compared the δ^(13)C org-based lake level fluctuations of Lake Ngoring for the last millennium,as previously reported,with the hydroclimatic history and the reconstructed TSI record.We conclude that the hydrological regime of Lake Ngoring has been mainly controlled by centennial fluctuations in precipitation for the last millennium,which is also dominated by solar activity.In general,it appears that solar activity has exerted a dominant influence on the hydrological regime of the SAYR on both decadal and centennial timescales,which is clearly manifested in the variations of lake area and water level of Lake Ngoring.展开更多
Here we combine n-alkanes preserved in a shell bar section from Qarhan paleolake, Qaidam Basin with the other sedimentary proxies to elucidate the lake evolution process during the period 39.7 to 17.5 14C ka BP (calib...Here we combine n-alkanes preserved in a shell bar section from Qarhan paleolake, Qaidam Basin with the other sedimentary proxies to elucidate the lake evolution process during the period 39.7 to 17.5 14C ka BP (calibrated age ranges from 43.5 to 22.4 cal. ka BP). In different stages, the n-alkane homologues exhibited different distribution modes indicative of variations in the surrounding vegetation and the hydrologic condition of the lake. The n-alkanes proxies (CPIh, ACLh, Paq) have the same trends as the summer solar insolation variation, implying that the summer insolation is the most important climatic factor driving the environmental changes and also indirectly controls lake evolution on the Tibetan Plateau. CPIh and ACLh as well as the total pollen concentration appear to show a trend comparable with methane concentration record from the GRIP ice core that reflected the Dansgaard-Oeschger events. This demonstrates that the paleoclimate variations in Qarhan area generally agree with global climate change and show rapid oscillations in late MIS3. These findings provide the latest molecular fossil evidence from paleolake sediments to confirm that lake evolution on Tibetan Plateau in late MIS3 was closely associated with enhanced summer insolation.展开更多
With the increased integration of photovoltaic(PV)power generation into active distribution networks,the operational challenges and their complexities are increased.Such networks need detailed characterization PV syst...With the increased integration of photovoltaic(PV)power generation into active distribution networks,the operational challenges and their complexities are increased.Such networks need detailed characterization PV systems under multiple operating conditions to understand true impacts.This paper presents a new mathematical model for a PV system to capture detailed effects of PV systems.The proposed model incorporates state transitions of components in a PV system and captures effects of insolation variations.The paper performs a reliability assessment incorporating PV systems at resource locations.The results suggest that the reliability performance of an active distribution network at stressed operating conditions might be influenced by the high penetration of PV system.Reliability performance of distribution networks that are high penetrated with PV systems can be affected by cloudy effects resulting from insolation variations.The proposed model can be used to quantify the level of reduction in reliability,resulting with cloudy effects.展开更多
By analyzing U and Th isotopic compositions of 41 samples in two stalagmites from Hulu Cave, Nanjing, we first discovered that variations of 238U and δ234U0 along the stalagmite growth-sequence (covering a period fro...By analyzing U and Th isotopic compositions of 41 samples in two stalagmites from Hulu Cave, Nanjing, we first discovered that variations of 238U and δ234U0 along the stalagmite growth-sequence (covering a period from 75 to 18 kaBP) are in high similarity to summer insolation curve at 33°N and δ18O-based climate record of the studied stalagmites. The concentration of 238U is mainly controlled by content of organic matter in the soil above the cave. This mechanism can be used to explain our result that 238U curve of stalagmites is in phase with fluctuation of the δ18O record of the same stalagmites and summer insolation at cave locality. However, 238U concentration curve vs. age is, in amplitude, inconsistent with the climatic curves, possibly due to complex processes of soil-water-rock interaction. δ234U0 indicates pedogenic intensity of soil profile above the cave and sensitively reflects alternations of pedogenesis and aeolian accumulation processes of Xiashu loess in Nanjing. Consequently,展开更多
The ability to take into account reflections from obstructions is of fundamental importance in building energy simulation (BES), because reflections can have a substantial influence on solar gains. In BES tools, this ...The ability to take into account reflections from obstructions is of fundamental importance in building energy simulation (BES), because reflections can have a substantial influence on solar gains. In BES tools, this ability is often implemented duplicating functionalities that have already been solved efficiently in lighting simulation tools. This happens because importing those functionalities from a lighting simulation tool (source) into a BES tool (target) is usually a complex operation producing non-portable results. This article demonstrates that this ability can be imported modularly and portably without intervening in the internals of the two tools. This can be obtained by: (1) creating, in the source tool, pairs of models which are analogue-on the one hand-to the original model in the target tool, and-on the other hand-to the model in the target tool hypothetically enriched with some predictive ability only available in the source tool;(2) measuring, at each time step, the ratio between the performances predicted by the source tool as regards the two analogue models;(3) re-scaling, at each time-step, the performance predicted by the target tool on the basis of that ratio. When appropriate analogue models are utilized, this strategy enables distinct simulation tools to work like an integrated computing unit.展开更多
Milankovitch Theory shows that glacial-interglacial cycles in the Quaternary are related to the variation of solar insolation forcing linked to the earth's astronomical parameters.However,the summer insolation at nor...Milankovitch Theory shows that glacial-interglacial cycles in the Quaternary are related to the variation of solar insolation forcing linked to the earth's astronomical parameters.However,the summer insolation at northern high latitudes,usually considered as the main external forcing for the ice age as Milankovitch pointed out,is marked by the 19- and 23-ka precession periodicities,which is not consistent with the glacial-interglacial cycles.On the other hand,recent studies indicate that the annual mean insolation dominated by the obliquity is also an important external forcing in glacial cycles.In this paper,it is assumed that the glacial oscillation is regulated simultaneously by the annual mean insolation at northern high latitudes related to obliquity and the noon insolation at summer solstice at the ice-line latitude related to precession. Only when both of them exceed some thresholds,does the ice sheet start to melt continuously to induce the global warming and deglaciation.Furthermore,the periodicity transition of glacial cycles at mid-Pleistocene was a natural change when the ice sheet thickness altered.A conceptual model based on this idea gives encouraging results compared with the isotopic data.展开更多
基金the DAAD,Germany,Council of Scientific and Industrial Research,Indiathe the Department of Science and Technology, India forproviding financial support
文摘Paired stable oxygen isotope and Mg/Ca analyses in calcite tests of the mixed-layer-dwelling planktic foraminifer Globigerinoides ruber has been used to reconstruct equatorial Indian Oceanδ18O of seawater (δ 18Osw ) over the last ~137 thousand years. On the basis of ice-volume-correctedδ18Osw (δ18Osw-ivc ), relative changes in sea surface salinity (SSS) have been estimated. The SSS estimates suggest three episodes of higher SSS (131-113 thousand years before present (kyr BP), 62-58 kyr BP, and 30-24 kyr BP) within the last glacial period as compared with the present. SSS comparison between interglacial episodes reveals that the surface seawater over the core site was significantly saltier during the penultimate interglacial than the Holocene. We suggest that the evolution of a seasonal insolation gradient between the Indian monsoon areas and the equator over the investigated time interval was instrumental in shaping the strength of the Indian winter and summer monsoons that left their imprints on the equatorial Indian Ocean SSS via freshwater input and wind-induced mixing. The study shows that the insolation difference between northern latitudes and the equator during winter affects monsoon strength in the Indian region, especially during cold intervals.
基金This work was supported in part by the DST,Govt.of India and British Council,UK vide no.DST/INT/UK/P-178/2017.
文摘This paper describes a novel approach in developing a model for forecasting of global insolation on a horizontal plane.In the proposed forecasting model,constraints,such as latitude and whole precipitable water content in vertical column of that location,are used.These parameters can be easily measurable with a global positioning system(GPS).The earlier model was developed by using the above datasets generated from different locations in India.The model has been verified by calculating theoretical global insolation for different sites covering east,west,north,south and the central region with the measured values from the same locations.The model has also been validated on a region,from which data was not used during the development of the model.In the model,clearness index coefficients(KT)are updated using the ensemble Kalman filter(EnKF)algorithm.The forecasting efficacies using the KT model and EnKF algorithm have also been verified by comparing two popular algorithms,namely the recursive least square(RLS)and Kalman filter(KF)algorithms.The minimum mean absolute percentage error(MAPE),mean square error(MSE)and correlation coefficient(R)value obtained in global solar insolation estimations using EnKF in one of the locations are 2.4%,0.0285 and 0.9866 respectively.
文摘The paper identifies and analyzes the geographical and temporal variability of solar energy in Kuwait. The fundamental solar trigonometric model has been modified to estimate daily and hourly solar radiation on horizontal surfaces on the basis of the more readily available meteorological data. The results demonstrate that Kuwait has an abundance of solar energy capability. An overview of the production and consumption of electrical energy, installed capacity, and peak loads in Kuwait is also presented. Finally, it is shown how the power produced from the photovoitaic (PV) cells depends on the solar radiation. The proposed PV module is made up of a combination of series and parallel cells to increase power, while the IoV characteristic and output power of the module each month may be obtained from the model.
文摘During a research cruise over the Pacific Ocean in 1989, solar irradiance was measured with a broad-band pyranometer along the cruise track. Cloud cover was photographed with an all-sky time-lapse came ra. Cloud types were observed and recorded. The data show that both the types and the amounts of clouds affect radiation fluxes on the sea surface. For low-level and middle-level clouds, the correlations (r) between measured irradiance (in Percent of calculated maximum irradiance) and cloud amount (in fraction of sky) were significant: r=-0. 79 and - 0. 66, respectively. For high-level clouds, the correlation was not significant: r=-0. 21. The results indicate that cloud shortwave forcing is a major modifier of the earth's surface insolation and change of cloud amount may affect global climate.
文摘From 1950 to 1987 a strong relationship existed between the El Nino-Southern Oscillation (ENSO) and HadCRUT4 global average temperature anomaly, interrupted occasionally by volcanic erup-tions. After 1987 the relationship diverged, with temperature anomaly increasing more than ex-pected, but was re-established after 1997 at an offset of ~0.48°C higher. The period of increased warming from 1987 to 1997 loosely coincided with the divergence of the global average tempera-ture anomalies over land, which are derived from observation station recordings, and the global average anomalies in sea surface temperatures. Land-based temperatures averaged 0.04°C below sea temperatures for the period 1950 to 1987 but after 1997 averaged 0.41°C above sea tempera-tures. The increase in the global average temperature anomaly and the divergence of land and sea surface temperatures also coincided with two significant changes in global average cloud cover. Total cloud cover decreased during the period from 1987 to 1997 and, for most of the remainder of the period from 1984 to 2009, decreases in low-level cloud were accompanied by increases in middle and upper level cloud. These changes can be found in both global average cloud cover and in each of the six 30°C-latitude bands. The impact of these changes in cloud cover can account for the variations in HadCRUT4 global average temperature anomalies and the divergence between land and sea temperatures.
文摘The astronomical theory of climate change is based on the solution of differential equations describing Earth’s orbital and rotational motions. The equations are used to calculate the change in insolation over the Earth’s surface. As a result of the author’s solution of the orbital problem, the periods and amplitudes of Earth-orbit variations and their evolution have been refined. Unlike previous studies, the equations of Earth’s rotational motion are solved completely. The Earth’s rotational axis precesses relative to a direction different from the direction of the orbit’s axial precession, and oscillates with periods of half a month, half a year and 18.6 years. Also, its oscillations occur with irregular periods of several tens of thousands of years and more. All these motions lead to oscillations of the obliquity in the range of 14.7° to 32.1°, which prove to be 7 - 8 times larger than obtained by a previous theory. In the same proportion, the Earth’s insolation oscillations increase in amplitude, with insolation extremes occurring in other epochs than those in the previous theory. The amplitudes and the onset times of the extremes correlate with known paleoclimate changes. Thirteen insolation periods of paleoclimate variation over an interval of 200 thousand years are identified. From the insolation evolution calculated over a time interval of 1 million years, 6 climate gradations from very cold to very warm are identified.
文摘Building envelope is a fence that controls heat exchange between interior and exterior and plays an essential role in providing thermal comfort conditions of residents. In recent years, due to the necessity of conserving energy and also preventing increased environmental pollution, the importance of sustainable construction has been doubled. Checking the problems of thermal behavior of the building envelope materials, and what influences in the heating and cooling loads exerted and energy consumption of buildings, are the questions that this research seeks to answer. In this regard, building information modelling analysis (BIM) has worthy contribution in the completion process of sustainable design;thus using software Design Builder, it is paid attention to simulation of the thermal behavior of two types of defined materials for the building envelope that was designed as a Research Institute of Renewable Energy of Yazd University. For Type 1 materials, two layers of brick have been selected, and for Type 2 a thermal insulation layer also added it. Results of the analysis showed that the use of materials Type 2 in the cooling load %4.8 and in the thermal load %62.5 reduction can be achieved which means reducing the load on active system and thus reducing the initial cost of building. Also reduction in annual energy consumption by almost %2.4 for cooling and %62.9 for heating buildings have been achieved, which makes saving non-renewable energy consumption, and consequently reducing environmental pollution as well as reducing current costs will be established.
基金This research is supported by the National Natural Science Foundation of China Grant(Nos.51705429&61801525)the Fundamental Research Funds for the Central Universities,Guangdong Natural Science Funds Grant(2018A030313400)+1 种基金Space Science and Technology Foundation,111 Project No.B13044UK Engineering and Physical Sciences Research Council(EPSRC)for support under grant EP/P018998/1,Newton Mobility Grant(IE161019)through Royal Society.
文摘Flexible,compact,lightweight and sustainable power sources are indispensable for modern wearable and personal electronics and small-unmanned aerial vehicles(UAVs).Hierarchical honeycomb has the unique merits of compact mesostructures,excellent energy absorption properties and considerable weight to strength ratios.Herein,a honeycomb-inspired triboelectric nanogenerator(h-TENG)is proposed for biomechanical and UAV morphing wing energy harvesting based on contact triboelectrification wavy surface of cellular honeycomb structure.The wavy surface comprises a multilayered thin film structure(combining polyethylene terephthalate,silver nanowires and fluorinated ethylene propylene)fabricated through high-temperature thermoplastic molding and wafer-level bonding process.With superior synchronization of large amounts of energy generation units with honeycomb cells,the manufactured h-TENG prototype produces the maximum instantaneous open-circuit voltage,short-circuit current and output power of 1207 V,68.5μA and 12.4 mW,respectively,corresponding to a remarkable peak power density of 0.275 mW cm^(−3)(or 2.48 mW g^(−1))under hand pressing excitations.Attributed to the excellent elastic property of self-rebounding honeycomb structure,the flexible and transparent h-TENG can be easily pressed,bent and integrated into shoes for real-time insole plantar pressure mapping.The lightweight and compact h-TENG is further installed into a morphing wing of small UAVs for efficiently converting the flapping energy of ailerons into electricity for the first time.This research demonstrates this new conceptualizing single h-TENG device’s versatility and viability for broad-range real-world application scenarios.
基金This work was supported by grants from the Provincial Science and Technology Project of Guangdong Province(No.2016A020220009)。
文摘Objective:To investigate the effectiveness of molding custom-made insoles for female patients with foot pain.Methods:The study included 20 patients whose insoles were prescribed according to biomechanical evaluations and molded by repositioning the subtalar joint in its neutral position using a simple set of tools.
文摘Objectives. The aim of this study was to investigate the effects of orthopaedic soles on the body posture. Methods. Forty-eight runners (21 men and 28 women) maintained a standing-up position on both feet with bare feet with neutral soles and orthopedic soles which contained bilaterally a podiatrist element of 3 mm height behind the metatarsal heads (Metatarsal Retro Capital Bar, MRCB). Stabilometric, plantar pressure and kinematic data in the sagittal plane on both sides were measured at 40 and 60 Hz, respectively. The position of the center of pressure on the anteroposterior axis (YCoP), the forefoot plantar pressure (FPP) and the anteroposterior position of the knee (Yk), the hip (YH), the shoulder (YS) and the ears (YE) with respect to the vertical axis passing through the joint of the ankle were determined for each experimental condition. Findings. The addition of a MRCB orthopedic element induced in backward displacement of CoP, hip, shoulder and ears (p CoP and FPP changes were significantly correlated with YH, YS and YE changes (p Conclusion. These results suggest that the addition of an orthopedic element located behind the metatarsal heads influences the overall position of the body and can help podiatrist in the care of their patients.
文摘Fall has become the second leading cause of unintentional injury, death, after road traffic injuries, for the elderly in Europe. This proportion will increase in the next decades and become more than ever a real public health issue. France was selected by the World Health Organization to be the first country to implement a program that reduces the coverage of the dependence. Commercial automatic fall detection devices can help seniors get back on their feet faster by reducing the time of emergency procedure. Many seniors do not take advantage of this potentially life-saving technology mainly because of intrusiveness constraints. After having reminded the context and the challenges of fall detection systems, this paper presents an original device which is unobtrusive, comfortable and very effective. The hardware architecture embedded into the sole and a new fall detection algorithm based on acceleration and time thresholds are presented. The algorithm introduces a new concept of differential acceleration to eliminate some drawbacks of current systems. Tests were carried out under real life conditions by 6 young participants for different ADLs. The data were analyzed blindly. We compared the detected falls and found a 100% sensibility and more than 93% sensitivity for all participants and scenarios.
文摘Objectives: We evaluated whether a valgus knee brace and an insole with subtalar strapping could reduce pain and improve functional scores over 12 months in patients with medial knee osteoarthritis (OA). Methods: OA was confirmed by radiography in all patients, who were divided into three groups: exercise (n = 44), insole (n = 55), and brace (n = 19). Clinical knee functions and gait analyses were evaluated. Results: After 12 months, the clinical results for all groups had improved compared to pretreatment findings. Although the knee varus moment decreased and the gait speed increased when the insole was worn initially, the effects of the insole decreased at 6 and 12 months. In contrast, the knee varus moment decreased and the gait speed increased when the brace was initially fitted. The effects of the brace were maintained during the 12 months. Conclusions: The insole was effective for patients with Kellgren-Lawrence Grades II and III, and the knee brace was effective for patients with Grades III and IV conditions. Furthermore, the knee brace was more effective when worn for more than 6 months, while the effects of the insoles were not continuous.
文摘The main objective of this work is to develop a technological solution to support active aging of frail older individuals. In this perspective, we designed a connected insole in order to encourage frail elderly persons to become more active in their daily life. The project presented in this paper, funded by the French National Research Agency, aims to design and evaluate an original solution to follow and encourage walking activity. The evaluation is performed in two stages: adjusting tests in a living-lab with nine healthy elderly, then clinical evaluation of three frail patients followed over one month. We designed a noninvasive wireless insole, which automatically measures gait parameters and transmits information to a remote terminal via a secure Internet connection. The first laboratory tests of this technological solution showed good reliability measurements as well as good user acceptability. The average distance error obtained on volunteers is 3.2% and the accuracy of the average walking speed is 96.8% thanks to design of a calibration system based on a personalized stride length measurement. Finally, the introduction of an induction charging instead of a button cell makes the system perfectly autonomous. In this paper, we present the specifications of the solution, the design of the connected insole, the methods used to measure desired parameters, the results of the living-lab tests, and the work in progress.
文摘An insole design with variable stiffness properties could be an effective conservative treatment option for knee osteoarthritis (OA). However, limited to the experimental conditions, stress distribution inside the cartilage of a knee joint is often difficult to be obtained. In this study, a finite element (FE)- based computational model of the human knee-foot-ankle complex is presented to investigate the redistribution of the internal stress of the knee joint using a variable stiffness insole. Based on relationship between the insole parameters and the resulting tissue stress data, additive manufacture technology (AM) could be a fast deliver of an optimal insole that meets patient characteristics. Insoles of four different material combinations were designed. Von-Mises stress declined significantly at the meniscus when the ratio of the lateral and medial stiffness of the insole changes. It suggests that the intervention of variable stiffness insole contributes to the rehabilitation of medial knee osteoarthritis (OA) and provide the guidance for the design of therapeutic insole.
基金supported by the National Natural Science Foundation of China(Grant Nos.42171160 and 42172205).
文摘In the north-eastern Qinghai-Tibet Plateau(QTP),the source area of the Yellow River(SAYR)has been experiencing significant changes in climatic and environmental conditions in recent decades.To date,few studies have combined modern hydrological conditions with paleoclimate records to explore the mechanism(s)of these changes.This study seeks to improve understanding of hydrological variability on decadal and centennial timescales in the SAYR and to identify its general cause.We first determined annual fluctuations in the surface area of Lake Ngoring from 1985 to 2020 using multi-temporal Landsat images.The results show that lake surface area changes were generally consistent with variations in precipitation,streamflow and the regional dry-wet index in the SAYR,suggesting that the water balance of the Lake Ngoring area is closely associated with regional hydroclimate changes.These records are also comparable to the stalagmite δ^(18)O monsoon record,as well fluctuations in the Southern Oscillation Index(SOI).Moreover,an association of high TSI(total solar insolation)anomalies and sunspot numbers with the expansion of Lake Ngoring surface area is observed,implying that solar activity is the key driving factor for hydrologic variability in the SAYR on a decadal timescale.Following this line of reasoning,we compared the δ^(13)C org-based lake level fluctuations of Lake Ngoring for the last millennium,as previously reported,with the hydroclimatic history and the reconstructed TSI record.We conclude that the hydrological regime of Lake Ngoring has been mainly controlled by centennial fluctuations in precipitation for the last millennium,which is also dominated by solar activity.In general,it appears that solar activity has exerted a dominant influence on the hydrological regime of the SAYR on both decadal and centennial timescales,which is clearly manifested in the variations of lake area and water level of Lake Ngoring.
基金supported by National Natural Science Foundation of China (Grant Nos. 40871096, 40371117)
文摘Here we combine n-alkanes preserved in a shell bar section from Qarhan paleolake, Qaidam Basin with the other sedimentary proxies to elucidate the lake evolution process during the period 39.7 to 17.5 14C ka BP (calibrated age ranges from 43.5 to 22.4 cal. ka BP). In different stages, the n-alkane homologues exhibited different distribution modes indicative of variations in the surrounding vegetation and the hydrologic condition of the lake. The n-alkanes proxies (CPIh, ACLh, Paq) have the same trends as the summer solar insolation variation, implying that the summer insolation is the most important climatic factor driving the environmental changes and also indirectly controls lake evolution on the Tibetan Plateau. CPIh and ACLh as well as the total pollen concentration appear to show a trend comparable with methane concentration record from the GRIP ice core that reflected the Dansgaard-Oeschger events. This demonstrates that the paleoclimate variations in Qarhan area generally agree with global climate change and show rapid oscillations in late MIS3. These findings provide the latest molecular fossil evidence from paleolake sediments to confirm that lake evolution on Tibetan Plateau in late MIS3 was closely associated with enhanced summer insolation.
文摘With the increased integration of photovoltaic(PV)power generation into active distribution networks,the operational challenges and their complexities are increased.Such networks need detailed characterization PV systems under multiple operating conditions to understand true impacts.This paper presents a new mathematical model for a PV system to capture detailed effects of PV systems.The proposed model incorporates state transitions of components in a PV system and captures effects of insolation variations.The paper performs a reliability assessment incorporating PV systems at resource locations.The results suggest that the reliability performance of an active distribution network at stressed operating conditions might be influenced by the high penetration of PV system.Reliability performance of distribution networks that are high penetrated with PV systems can be affected by cloudy effects resulting from insolation variations.The proposed model can be used to quantify the level of reduction in reliability,resulting with cloudy effects.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 49972055).
文摘By analyzing U and Th isotopic compositions of 41 samples in two stalagmites from Hulu Cave, Nanjing, we first discovered that variations of 238U and δ234U0 along the stalagmite growth-sequence (covering a period from 75 to 18 kaBP) are in high similarity to summer insolation curve at 33°N and δ18O-based climate record of the studied stalagmites. The concentration of 238U is mainly controlled by content of organic matter in the soil above the cave. This mechanism can be used to explain our result that 238U curve of stalagmites is in phase with fluctuation of the δ18O record of the same stalagmites and summer insolation at cave locality. However, 238U concentration curve vs. age is, in amplitude, inconsistent with the climatic curves, possibly due to complex processes of soil-water-rock interaction. δ234U0 indicates pedogenic intensity of soil profile above the cave and sensitively reflects alternations of pedogenesis and aeolian accumulation processes of Xiashu loess in Nanjing. Consequently,
文摘The ability to take into account reflections from obstructions is of fundamental importance in building energy simulation (BES), because reflections can have a substantial influence on solar gains. In BES tools, this ability is often implemented duplicating functionalities that have already been solved efficiently in lighting simulation tools. This happens because importing those functionalities from a lighting simulation tool (source) into a BES tool (target) is usually a complex operation producing non-portable results. This article demonstrates that this ability can be imported modularly and portably without intervening in the internals of the two tools. This can be obtained by: (1) creating, in the source tool, pairs of models which are analogue-on the one hand-to the original model in the target tool, and-on the other hand-to the model in the target tool hypothetically enriched with some predictive ability only available in the source tool;(2) measuring, at each time step, the ratio between the performances predicted by the source tool as regards the two analogue models;(3) re-scaling, at each time-step, the performance predicted by the target tool on the basis of that ratio. When appropriate analogue models are utilized, this strategy enables distinct simulation tools to work like an integrated computing unit.
基金Supported by the National Natural Science Foundation of China under Grant Nos.40875043 and 40631002the National Program on Key Basic Research of China(2010CB428506)
文摘Milankovitch Theory shows that glacial-interglacial cycles in the Quaternary are related to the variation of solar insolation forcing linked to the earth's astronomical parameters.However,the summer insolation at northern high latitudes,usually considered as the main external forcing for the ice age as Milankovitch pointed out,is marked by the 19- and 23-ka precession periodicities,which is not consistent with the glacial-interglacial cycles.On the other hand,recent studies indicate that the annual mean insolation dominated by the obliquity is also an important external forcing in glacial cycles.In this paper,it is assumed that the glacial oscillation is regulated simultaneously by the annual mean insolation at northern high latitudes related to obliquity and the noon insolation at summer solstice at the ice-line latitude related to precession. Only when both of them exceed some thresholds,does the ice sheet start to melt continuously to induce the global warming and deglaciation.Furthermore,the periodicity transition of glacial cycles at mid-Pleistocene was a natural change when the ice sheet thickness altered.A conceptual model based on this idea gives encouraging results compared with the isotopic data.