This paper studies motor joint control of a 4-degree-of-freedom(DoF)robotic manipulator using learning-based Adaptive Dynamic Programming(ADP)approach.The manipulator’s dynamics are modelled as an open-loop 4-link se...This paper studies motor joint control of a 4-degree-of-freedom(DoF)robotic manipulator using learning-based Adaptive Dynamic Programming(ADP)approach.The manipulator’s dynamics are modelled as an open-loop 4-link serial kinematic chain with 4 Degrees of Freedom(DoF).Decentralised optimal controllers are designed for each link using ADP approach based on a set of cost matrices and data collected from exploration trajectories.The proposed control strategy employs an off-line,off-policy iterative approach to derive four optimal control policies,one for each joint,under exploration strategies.The objective of the controller is to control the position of each joint.Simulation and experimental results show that four independent optimal controllers are found,each under similar exploration strategies,and the proposed ADP approach successfully yields optimal linear control policies despite the presence of these complexities.The experimental results conducted on the Quanser Qarm robotic platform demonstrate the effectiveness of the proposed ADP controllers in handling significant dynamic nonlinearities,such as actuation limitations,output saturation,and filter delays.展开更多
Geothermal energy,a form of renewable energy,has been extensively utilized for building heating.However,there is a lack of detailed comparative studies on the use of shallow and medium-deep geothermal energy in buildi...Geothermal energy,a form of renewable energy,has been extensively utilized for building heating.However,there is a lack of detailed comparative studies on the use of shallow and medium-deep geothermal energy in building energy systems,which are essential for decision-making.Therefore,this paper presents a comparative study of the performance and economic analysis of shallow and medium-deep borehole heat exchanger heating systems.Based on the geological parameters of Xi’an,China and commonly used borehole heat exchanger structures,numerical simulationmethods are employed to analyze performance and economic efficiency.The results indicate that increasing the spacing between shallow borehole heat exchangers can effectively reduce thermal interference between the pipes and improve heat extraction performance.As the flow rate increases,the outlet water temperature ranges from 279.3 to 279.7 K,with heat extraction power varying between 595 and 609 W.For medium-deep borehole heat exchangers,performance predictions show that a higher flow rate results in greater heat extraction power.However,when the flow rate exceeds 30 m^(3)/h,further increases in flow rate have only a minor effect on enhancing heat extraction power.Additionally,the economic analysis reveals that the payback period for shallow geothermal heating systems ranges from 10 to 11 years,while for medium-deep geothermal heating systems,it varies more widely from 3 to 25 years.Therefore,the payback period for medium-deep geothermal heating systems is more significantly influenced by operational and installation parameters,and optimizing these parameters can considerably shorten the payback period.The results of this study are expected to provide valuable insights into the efficient and cost-effective utilization of geothermal energy for building heating.展开更多
Recent studies indicated that vitamin A(VA)might be involved in the pathology of type 2 diabetes mellitus(T2DM).This cross-sectional study was conducted to explore the association between circulating VA level and T2DM...Recent studies indicated that vitamin A(VA)might be involved in the pathology of type 2 diabetes mellitus(T2DM).This cross-sectional study was conducted to explore the association between circulating VA level and T2DM.A total of 1818 subjects aged 50 years old and above were recruited from the community.Binomial logistic regression and restricted cubic spline(RCS)were applied to analyze the association of plasma VA level with the risk of T2DM.Serum VA and lipid-adjusted VA levels of T2DM patients were significantly higher than that of non-T2DM subjects(P<0.05).The ratios of plasma VA/total cholesterol(TC),VA/high-density lipoprotein cholesterol(HDL-c)and VA/low-density lipoprotein cholesterol(LDL-c)were positively associated with the risk of T2DM in the aging population(P<0.05).Compared with the Q1 level,subjects with Q2 to Q3 levels of plasma VA/triglyceride(TG)have decreased risk of T2DM(odds ratio(OR)Q2=0.68,P_(Q2)=0.021;ORQ3=0.59,P_(Q3)<0.01).Our results indicated that the imbalance of circulating lipids and VA might affect the relationship between VA and T2DM.The middle and aging subjects with higher ratios of plasma VA/TC,VA/HDL-c,and VA/LDL-c displayed increased risk for T2DM,but the moderate ratio of VA/TG might protect against risk of T2DM.展开更多
Autograft or metal implants are routinely used in skeletal repair.However,they fail to provide long-term clinical resolution,necessitating a functional biomimetic tissue engineering alternative.The use of native human...Autograft or metal implants are routinely used in skeletal repair.However,they fail to provide long-term clinical resolution,necessitating a functional biomimetic tissue engineering alternative.The use of native human bone tissue for synthesizing a biomimeticmaterial inkfor three-dimensional(3D)bioprintingof skeletal tissueis anattractivestrategyfor tissueregeneration.Thus,human bone extracellular matrix(bone-ECM)offers an exciting potential for the development of an appropriate microenvironment for human bone marrow stromal cells(HBMSCs)to proliferate and differentiate along the osteogenic lineage.In this study,we engineered a novel material ink(LAB)by blending human bone-ECM(B)with nanoclay(L,Laponite®)and alginate(A)polymers using extrusion-based deposition.The inclusion of the nanofiller and polymeric material increased the rheology,printability,and drug retention properties and,critically,the preservation of HBMSCs viability upon printing.The composite of human bone-ECM-based 3D constructs containing vascular endothelial growth factor(VEGF)enhanced vascularization after implantation in an ex vivo chick chorioallantoic membrane(CAM)model.The inclusion of bone morphogenetic protein-2(BMP-2)with the HBMSCs further enhanced vascularization and mineralization after only seven days.This study demonstrates the synergistic combination of nanoclay with biomimetic materials(alginate and bone-ECM)to support the formation of osteogenic tissue both in vitro and ex vivo and offers a promising novel 3D bioprinting approach to personalized skeletal tissue repair.展开更多
The prompt spread of COVID-19 has emphasized the necessity for effective and precise diagnostic tools.In this article,a hybrid approach in terms of datasets as well as the methodology by utilizing a previously unexplo...The prompt spread of COVID-19 has emphasized the necessity for effective and precise diagnostic tools.In this article,a hybrid approach in terms of datasets as well as the methodology by utilizing a previously unexplored dataset obtained from a private hospital for detecting COVID-19,pneumonia,and normal conditions in chest X-ray images(CXIs)is proposed coupled with Explainable Artificial Intelligence(XAI).Our study leverages less preprocessing with pre-trained cutting-edge models like InceptionV3,VGG16,and VGG19 that excel in the task of feature extraction.The methodology is further enhanced by the inclusion of the t-SNE(t-Distributed Stochastic Neighbor Embedding)technique for visualizing the extracted image features and Contrast Limited Adaptive Histogram Equalization(CLAHE)to improve images before extraction of features.Additionally,an AttentionMechanism is utilized,which helps clarify how the modelmakes decisions,which builds trust in artificial intelligence(AI)systems.To evaluate the effectiveness of the proposed approach,both benchmark datasets and a private dataset obtained with permissions from Jinnah PostgraduateMedical Center(JPMC)in Karachi,Pakistan,are utilized.In 12 experiments,VGG19 showcased remarkable performance in the hybrid dataset approach,achieving 100%accuracy in COVID-19 vs.pneumonia classification and 97%in distinguishing normal cases.Overall,across all classes,the approach achieved 98%accuracy,demonstrating its efficiency in detecting COVID-19 and differentiating it fromother chest disorders(Pneumonia and healthy)while also providing insights into the decision-making process of the models.展开更多
Software cost estimation is a crucial aspect of software project management,significantly impacting productivity and planning.This research investigates the impact of various feature selection techniques on software c...Software cost estimation is a crucial aspect of software project management,significantly impacting productivity and planning.This research investigates the impact of various feature selection techniques on software cost estimation accuracy using the CoCoMo NASA dataset,which comprises data from 93 unique software projects with 24 attributes.By applying multiple machine learning algorithms alongside three feature selection methods,this study aims to reduce data redundancy and enhance model accuracy.Our findings reveal that the principal component analysis(PCA)-based feature selection technique achieved the highest performance,underscoring the importance of optimal feature selection in improving software cost estimation accuracy.It is demonstrated that our proposed method outperforms the existing method while achieving the highest precision,accuracy,and recall rates.展开更多
The influence of Mo and ZrO_(2)nanoparticles addition on the interfacial properties and shear strength of Sn58Bi solder joint was investigated.The interfacial microstructures of Sn58Bi/Cu,Sn58Bi+Mo/Cu and Sn58Bi+ZrO_(...The influence of Mo and ZrO_(2)nanoparticles addition on the interfacial properties and shear strength of Sn58Bi solder joint was investigated.The interfacial microstructures of Sn58Bi/Cu,Sn58Bi+Mo/Cu and Sn58Bi+ZrO_(2)/Cu solder joints were analysed using a scanning electron microscope(SEM)coupled with energy dispersive X-ray(EDX)and the X-ray diffraction(XRD).Intermetallic compounds(IMCs)of MoSn_(2)are detected in the Sn58Bi+Mo/Cu solder joint,while SnZr,Zr_(5)Sn_(3),ZrCu and ZrSn_(2)are detected in Sn58Bi+ZrO_(2)/Cu solder joint.IMC layers for both composite solders comprise of Cu_(6)Sn_(5) and Cu_(3)Sn.The SEM images of these layers were used to measure the IMC layer’s thickness.The average IMC layer’s thickness is 1.4431μm for Sn58Bi+Mo/Cu and 0.9112μm for Sn58Bi+ZrO_(2)/Cu solder joints.Shear strength of the solder joints was investigated via the single shear lap test method.The average maximum load and shear stress of the Sn58Bi+Mo/Cu and Sn58Bi+ZrO_(2)/Cu solder joints are increased by 33%and 69%,respectively,as compared to those of the Sn58Bi/Cu solder joint.By comparing both composite solder joints,the latter prevails better as adding smaller sized ZrO_(2)nanoparticles improves the interfacial properties granting a stronger solder joint.展开更多
In the increasingly decentralized energy environment,economical power dispatching from distributed generations(DGs)is crucial to minimizing operating costs,optimizing resource utilization,and guaranteeing a consistent...In the increasingly decentralized energy environment,economical power dispatching from distributed generations(DGs)is crucial to minimizing operating costs,optimizing resource utilization,and guaranteeing a consistent and sustainable supply of electricity.A comprehensive review of optimization techniques for economic power dispatching from distributed generations is imperative to identify the most effective strategies for minimizing operational costs while maintaining grid stability and sustainability.The choice of optimization technique for economic power dispatching from DGs depends on a number of factors,such as the size and complexity of the power system,the availability of computational resources,and the specific requirements of the application.Optimization techniques for economic power dispatching from distributed generations(DGs)can be classified into two main categories:(i)Classical optimization techniques,(ii)Heuristic optimization techniques.In classical optimization techniques,the linear programming(LP)model is one of the most popular optimization methods.Utilizing the LP model,power demand and network constraints are met while minimizing the overall cost of generating electricity from DGs.This approach is efficient in determining the best DGs dispatch and is capable of handling challenging optimization issues in the large-scale system including renewables.The quadratic programming(QP)model,a classical optimization technique,is a further popular optimization method,to consider non-linearity.The QP model can take into account the quadratic cost of energy production,with consideration constraints like network capacity,voltage,and frequency.The metaheuristic optimization techniques are also used for economic power dispatching from DGs,which include genetic algorithms(GA),particle swarm optimization(PSO),and ant colony optimization(ACO).Also,Some researchers are developing hybrid optimization techniques that combine elements of classical and heuristic optimization techniques with the incorporation of droop control,predictive control,and fuzzy-based methods.These methods can deal with large-scale systems with many objectives and non-linear,non-convex optimization issues.The most popular approaches are the LP and QP models,while more difficult problems are handled using metaheuristic optimization techniques.In summary,in order to increase efficiency,reduce costs,and ensure a consistent supply of electricity,optimization techniques are essential tools used in economic power dispatching from DGs.展开更多
Phenol-containing wastewater is typical organic wastewater,and its treatment is arduous.An advanced method to treat this type of wastewater is persulfate activation.Environmentally friendly ceriummanganese composite o...Phenol-containing wastewater is typical organic wastewater,and its treatment is arduous.An advanced method to treat this type of wastewater is persulfate activation.Environmentally friendly ceriummanganese composite oxide materials were synthesized by hydrothermal method and applied to the phenol degradation process.Various ratios of cerium and manganese,as well as the amount of sodium hydroxide,were investigated.The solid solutions of cerium and manganese were formed and confirmed by X-ray diffraction(XRD) and transmission electron microscopy(TEM).H_(2)-temperature programmed reduction(H_(2)-TPR) and X-ray photoelectron spectroscopy(XPS) were utilized to analyze the synergistic effect of cerium and manganese.It is found that there is a transformation between Ce^(4+)/Ce^(3+) and Mn^(2+)/Mn^(3+),which makes the material more trivalent manganese and thereby increases the catalytic activity.The effect of materials in catalyzing phenol degradation by peroxodisulfate(PDS) under various preparation conditions is discussed and high-effciency removal of phenol can be achieved and the removal rate at 180 min is close to 100%.The kinetic of this process was investigated and activation energy of phenol degradation is 62,35 kJ/mol.The degradation pathway of phenol was studied and it is found that PDS can be activated by low metal ions and the OH and SO_(4·)^(-)radicals play crucial roles according to the quenching experiments.展开更多
The DNS over HTTPS(Hypertext Transfer Protocol Secure)(DoH)is a new technology that encrypts DNS traffic,enhancing the privacy and security of end-users.However,the adoption of DoH is still facing several research cha...The DNS over HTTPS(Hypertext Transfer Protocol Secure)(DoH)is a new technology that encrypts DNS traffic,enhancing the privacy and security of end-users.However,the adoption of DoH is still facing several research challenges,such as ensuring security,compatibility,standardization,performance,privacy,and increasing user awareness.DoH significantly impacts network security,including better end-user privacy and security,challenges for network security professionals,increasing usage of encrypted malware communication,and difficulty adapting DNS-based security measures.Therefore,it is important to understand the impact of DoH on network security and develop newprivacy-preserving techniques to allowthe analysis of DoH traffic without compromising user privacy.This paper provides an in-depth analysis of the effects of DoH on cybersecurity.We discuss various techniques for detecting DoH tunneling and identify essential research challenges that need to be addressed in future security studies.Overall,this paper highlights the need for continued research and development to ensure the effectiveness of DoH as a tool for improving privacy and security.展开更多
COVID-19 pandemic restrictions limited all social activities to curtail the spread of the virus.The foremost and most prime sector among those affected were schools,colleges,and universities.The education system of en...COVID-19 pandemic restrictions limited all social activities to curtail the spread of the virus.The foremost and most prime sector among those affected were schools,colleges,and universities.The education system of entire nations had shifted to online education during this time.Many shortcomings of Learning Management Systems(LMSs)were detected to support education in an online mode that spawned the research in Artificial Intelligence(AI)based tools that are being developed by the research community to improve the effectiveness of LMSs.This paper presents a detailed survey of the different enhancements to LMSs,which are led by key advances in the area of AI to enhance the real-time and non-real-time user experience.The AI-based enhancements proposed to the LMSs start from the Application layer and Presentation layer in the form of flipped classroom models for the efficient learning environment and appropriately designed UI/UX for efficient utilization of LMS utilities and resources,including AI-based chatbots.Session layer enhancements are also required,such as AI-based online proctoring and user authentication using Biometrics.These extend to the Transport layer to support real-time and rate adaptive encrypted video transmission for user security/privacy and satisfactory working of AI-algorithms.It also needs the support of the Networking layer for IP-based geolocation features,the Virtual Private Network(VPN)feature,and the support of Software-Defined Networks(SDN)for optimum Quality of Service(QoS).Finally,in addition to these,non-real-time user experience is enhanced by other AI-based enhancements such as Plagiarism detection algorithms and Data Analytics.展开更多
Over the last decade,the oriented strand board(OSB)market presented meaningful growth.However,as a woodbased product,because of its anatomical structure and chemical composition,OSB can be damaged by biodeterioration ...Over the last decade,the oriented strand board(OSB)market presented meaningful growth.However,as a woodbased product,because of its anatomical structure and chemical composition,OSB can be damaged by biodeterioration agents.Given that,the biodeterioration of OSB panels must be investigated to improve its durability.In this way,this work analyses the biological resistance against termites(Cryptotermes brevis and Nasutitermes corniger)of heat-treated OSB panels made with Eucalyptus wood glued with vegetable-based polyurethane-an ecofriendly and sustainable adhesive derived from castor oil.Various panels were produced with different layers compositions(face:core:face of 25:50:25 and 30:40:30)in wood mass proportion and were submitted to postproduction heat treatment(at 175℃ and 200℃)replacing the use of chemical insecticides.The influence of the layers variation and heat treatment temperature were evaluated,and these results were compared with commercial panels(made from pinus wood with insecticide).The results showed that the heat treatment did not improve the resistance against termite attack.However,all the experimental panels presented a satisfactory performance that was compatible with the commercial panels produced with insecticide available in the Brazilian market.The combination of Eucalyptus wood and castor oil adhesive to produce OSB,in any variation of layer composition,demonstrated natural resistance against termite attack compatible with the commercial panels,even without using chemical additives to increase durability.展开更多
Mobile and Internet network coverage plays an important role in digital transformation and the exploitation of new services. The evolution of mobile networks from the first generation (1G) to the 5th generation is sti...Mobile and Internet network coverage plays an important role in digital transformation and the exploitation of new services. The evolution of mobile networks from the first generation (1G) to the 5th generation is still a long process. 2G networks have developed the messaging service, which complements the already operational voice service. 2G technology has rapidly progressed to the third generation (3G), incorporating multimedia data transmission techniques. It then progressed to fourth generation (4G) and LTE (Long Term Evolution), increasing the transmission speed to improve 3G. Currently, developed countries have already moved to 5G. In developing countries, including Burundi, a member of the East African Community (ECA) where more than 80% are connected to 2G technologies, 40% are connected to the 3G network and 25% to the 4G network and are not yet connected to the 5G network and then still a process. The objective of this article is to analyze the coverage of 2G, 3G and 4G networks in Burundi. This analysis will make it possible to identify possible deficits in order to reduce the digital divide between connected urban areas and remote rural areas. Furthermore, this analysis will draw the attention of decision-makers to the need to deploy networks and coverage to allow the population to access mobile and Internet services and thus enable the digitalization of the population. Finally, this article shows the level of coverage, the digital divide and an overview of the deployment of base stations (BTS) throughout the country to promote the transformation and digital inclusion of services.展开更多
This study evaluates the effects of the initial situation of the site (slope and quality of the soil with its resistance characteristics), building loads, support and drainage/non-drainage on the safety and stability ...This study evaluates the effects of the initial situation of the site (slope and quality of the soil with its resistance characteristics), building loads, support and drainage/non-drainage on the safety and stability of sloping sites. The objective is to contribute to the stabilization of sloping sites under building loads. Considering a sloping site under building loads in the city of Bujumbura in Burundi facing the problem of instability, an experimental study of the site’s soils is first carried out in the laboratory. Secondly, an analysis by numerical simulation of stability is carried out based on 3 main simulation cases: By first considering an initial situation (unloaded), then a loaded situation without support and a loaded situation with support. The calculation is carried out in a drained state and in an undrained state, with a water table blocked at depth to simulate the reality on the ground. Three buildings of different levels are designed according to the existing buildings and their loads are determined for the loaded case simulations. The results of the analysis thus make it possible to assess the effect on safety and stability of: 1) the slope of the unloaded site and the quality of the soil with its resistance characteristics, 2) the loads of the buildings or their intensive increase, 3) the drained or undrained state of the soil on the site, 4) the support or non-support of the unloaded or loaded, drained or undrained sloping site.展开更多
The application of carbon nanomaterials, particularly graphene and carbon nanotubes, in cement-based composites is highly significant. These materials demonstrate the multifunctionality of carbon and offer extensive p...The application of carbon nanomaterials, particularly graphene and carbon nanotubes, in cement-based composites is highly significant. These materials demonstrate the multifunctionality of carbon and offer extensive possibilities for technological advancements. This research analyzes how the integration of graphene into cement-based composites enhances damping and mechanical properties, thereby contributing to the safety and durability of structures. Research on carbon nanomaterials is ongoing and is expected to continue driving innovation across various industrial sectors, promoting the sustainable development of building materials.展开更多
This paper conducted experimental studies on the damping and mechanical properties of carbon nanotube-nanosilica-cement composite materials with different carbon nanotube contents. The damping and mechanical propertie...This paper conducted experimental studies on the damping and mechanical properties of carbon nanotube-nanosilica-cement composite materials with different carbon nanotube contents. The damping and mechanical properties enhancement mechanisms were analyzed and compared through the porosity structure test, XRD analysis, and scanning electron microscope observation. The results show that the introduction of nanosilica significantly improves the dispersion of carbon nanotubes in the cement matrix. At the same time, the addition of nanosilica not only effectively reduces the critical pore size and average pore size of the cement composite material, but also exhibits good synergistic effects with carbon nanotubes, which can significantly optimize the pore structure. Finally, a rationalization suggestion for the co-doping of nanosilica and carbon nanotubes was given to achieve a significant increase in the flexural strength, compressive strength and loss factor of cement-based materials.展开更多
This article explores the comparison between the probability method and the least squares method in the design of linear predictive models. It points out that these two approaches have distinct theoretical foundations...This article explores the comparison between the probability method and the least squares method in the design of linear predictive models. It points out that these two approaches have distinct theoretical foundations and can lead to varied or similar results in terms of precision and performance under certain assumptions. The article underlines the importance of comparing these two approaches to choose the one best suited to the context, available data and modeling objectives.展开更多
This study is an extension of the previous work done with ARS-680 Environmental Chamber. Drying is a complex operation that demands much energy and time. Drying is essentially important for preservation of ginger rhiz...This study is an extension of the previous work done with ARS-680 Environmental Chamber. Drying is a complex operation that demands much energy and time. Drying is essentially important for preservation of ginger rhizome. Drying of ginger was modeled, and then the effective diffusion coefficient and activation energy were determined. For this purpose, the experiments were done at six levels of varied temperatures: 10°C, 20°C, 30°C, 40°C, 50°C and 60°C. The values of effective diffusion coefficients obtained in this work for the variously treated ginger rhizomes closely agreed with the average effective diffusion coefficients of other notable authors who determined the drying kinetics and convective heat transfer coefficients of ginger slices.展开更多
The early collapse of habitats in the spontaneous neighborhoods of the South-East of N’Djamena city pushed us to carry out investigations on the soil characteristics of the Ambatta 1 (Z1), Ambatta 2 (Z2), and Sigu...The early collapse of habitats in the spontaneous neighborhoods of the South-East of N’Djamena city pushed us to carry out investigations on the soil characteristics of the Ambatta 1 (Z1), Ambatta 2 (Z2), and Siguété (Z3) neighborhoods in this city. XRF (X-Ray Fluorescence), XRD (X-Ray Diffraction), FTIR (Fourier Transform InfraRed), SEM (Scanning Electron Microscopy), and ATG/DTA (Thermogravimetry Analysis/Differential Thermal Analysis) were conducted for microstructural and thermal identification. The geochemistry of the three soils studied revealed the presence of SiO2 (49.03% - 73.80%), Al2O3 (08.35% - 17.34%), and Fe2O3 (03.79% - 10.90%) as major elements. The alkalines and alkaline earth elements include potassium K2O (02.57% - 03.07%), magnesium MgO (0.47% - 01.21%), titanium TiO2 (0.81% - 01.41%), sodium Na2O (01.01% - 01.13%) and calcium CaO (01.28% - 03.28%). The fire loss of 09.90% on average remains low. XRD revealed the presence of quartz (~64.28%), feldspar (~07.14%), which are non-clay minerals, and clay minerals like kaolinite (~14.85%), illite (~07.14%) and some traces of smectite and amphibite on all three sites. These oxides were confirmed by FTIR analysis through peaks illustrating the vibrational movements specific to these oxides. SEM shows particles in the increasingly shaped, rounded, shiny sand grains. This is the presence of quartz. These quartz micro textures of abrasive surfaces and topography with conchoidal fractures predict promising mechanical results. Smectite appears in wavy clusters, kaolinite in the form of shiny crystals, and illite materializes by the irregularity of the crystalline shape. These constituents are represented by the presence of their oxides specified by geochemistry. Thermally, the three samples overall retain more than 94% of their constituent on average for a temperature range reaching 950˚C, which predestines them for specific applications. Thus, this study aims to stabilize constructions using local materials after having mastered their constituents.展开更多
Creep and anelastic backflow behaviors of pure copper （4N Cu） with grain size dg=40 μm were investigated at low temperatures of T〈0.3Tm （Tm is melting point） and ultra-low creep rates of ε≤1×10^-10 s^-1 b...Creep and anelastic backflow behaviors of pure copper （4N Cu） with grain size dg=40 μm were investigated at low temperatures of T〈0.3Tm （Tm is melting point） and ultra-low creep rates of ε≤1×10^-10 s^-1 by a high strain-resolution measurement （the helicoid spring specimen technique）. Analysis of creep data was based on the scaling factors of creep curves instead of the conventional extrapolated steady-state creep rate. Power-law creep equation is suggested to be the best for describing the primary transient creep behavior, because the pre-parameter does not apparently change with elapsed time. The observed anelastic strains are 1/6 of the calculated elastic strains, and linear viscous behavior was identified from the logarithm plot of the anelastic strain rate versus anelastic strain （slope equals 1）. Therefore, the creep anelasticity is suggested to be due to the unbowing of there-dimensional network of dislocations.展开更多
基金supported by the DEEPCOBOT project under Grant 306640/O70 funded by the Research Council of Norway.
文摘This paper studies motor joint control of a 4-degree-of-freedom(DoF)robotic manipulator using learning-based Adaptive Dynamic Programming(ADP)approach.The manipulator’s dynamics are modelled as an open-loop 4-link serial kinematic chain with 4 Degrees of Freedom(DoF).Decentralised optimal controllers are designed for each link using ADP approach based on a set of cost matrices and data collected from exploration trajectories.The proposed control strategy employs an off-line,off-policy iterative approach to derive four optimal control policies,one for each joint,under exploration strategies.The objective of the controller is to control the position of each joint.Simulation and experimental results show that four independent optimal controllers are found,each under similar exploration strategies,and the proposed ADP approach successfully yields optimal linear control policies despite the presence of these complexities.The experimental results conducted on the Quanser Qarm robotic platform demonstrate the effectiveness of the proposed ADP controllers in handling significant dynamic nonlinearities,such as actuation limitations,output saturation,and filter delays.
基金support by the Shanghai Engineering Research Center for Shallow Geothermal Energy(DRZX-202306)Shaanxi Coal Geology Group Co.,Ltd.(SMDZ-ZD2024-23)+4 种基金Key Laboratory of Coal Resources Exploration and Comprehensive Utilization,Ministry of Natural Resources,China(ZP2020-1)Shaanxi Investment Group Co.,Ltd.(SIGC2023-KY-05)Key Research and Development Projects of Shaanxi Province(2023-GHZD-54)Shaanxi Qinchuangyuan Scientist+Engineer Team Construction Project(2022KXJ-049)China Postdoctoral Science Foundation(2023M742802,2024T170721).
文摘Geothermal energy,a form of renewable energy,has been extensively utilized for building heating.However,there is a lack of detailed comparative studies on the use of shallow and medium-deep geothermal energy in building energy systems,which are essential for decision-making.Therefore,this paper presents a comparative study of the performance and economic analysis of shallow and medium-deep borehole heat exchanger heating systems.Based on the geological parameters of Xi’an,China and commonly used borehole heat exchanger structures,numerical simulationmethods are employed to analyze performance and economic efficiency.The results indicate that increasing the spacing between shallow borehole heat exchangers can effectively reduce thermal interference between the pipes and improve heat extraction performance.As the flow rate increases,the outlet water temperature ranges from 279.3 to 279.7 K,with heat extraction power varying between 595 and 609 W.For medium-deep borehole heat exchangers,performance predictions show that a higher flow rate results in greater heat extraction power.However,when the flow rate exceeds 30 m^(3)/h,further increases in flow rate have only a minor effect on enhancing heat extraction power.Additionally,the economic analysis reveals that the payback period for shallow geothermal heating systems ranges from 10 to 11 years,while for medium-deep geothermal heating systems,it varies more widely from 3 to 25 years.Therefore,the payback period for medium-deep geothermal heating systems is more significantly influenced by operational and installation parameters,and optimizing these parameters can considerably shorten the payback period.The results of this study are expected to provide valuable insights into the efficient and cost-effective utilization of geothermal energy for building heating.
基金funded by the National Natural Science Foundation of China(8217350881973027)Beijing Highlevel Public Health Technical Personnel Training Program(No.2022-3-032)。
文摘Recent studies indicated that vitamin A(VA)might be involved in the pathology of type 2 diabetes mellitus(T2DM).This cross-sectional study was conducted to explore the association between circulating VA level and T2DM.A total of 1818 subjects aged 50 years old and above were recruited from the community.Binomial logistic regression and restricted cubic spline(RCS)were applied to analyze the association of plasma VA level with the risk of T2DM.Serum VA and lipid-adjusted VA levels of T2DM patients were significantly higher than that of non-T2DM subjects(P<0.05).The ratios of plasma VA/total cholesterol(TC),VA/high-density lipoprotein cholesterol(HDL-c)and VA/low-density lipoprotein cholesterol(LDL-c)were positively associated with the risk of T2DM in the aging population(P<0.05).Compared with the Q1 level,subjects with Q2 to Q3 levels of plasma VA/triglyceride(TG)have decreased risk of T2DM(odds ratio(OR)Q2=0.68,P_(Q2)=0.021;ORQ3=0.59,P_(Q3)<0.01).Our results indicated that the imbalance of circulating lipids and VA might affect the relationship between VA and T2DM.The middle and aging subjects with higher ratios of plasma VA/TC,VA/HDL-c,and VA/LDL-c displayed increased risk for T2DM,but the moderate ratio of VA/TG might protect against risk of T2DM.
基金supported by grants from the Biotechnology and Biological Sciences Research Council(Nos.BBSRC LO21071/and BB/L00609X/1)UK Regenerative Medicine Platform Hub Acellular Approaches for Therapeutic Delivery(No.MR/K026682/1)+3 种基金Acellular Hub,SMART Materials 3D Architecture(No.MR/R015651/1)the UK Regenerative Medicine Platform(No.MR/L012626/1 Southampton Imaging)to ROCOMRCAMED Regenerative Medicine and Stem Cell Research Initiative(No.MR/V00543X/1)to JID,ROCO and YHKGC acknowledges funding from AIRC Aldi Fellowship under grant agreement No.25412.
文摘Autograft or metal implants are routinely used in skeletal repair.However,they fail to provide long-term clinical resolution,necessitating a functional biomimetic tissue engineering alternative.The use of native human bone tissue for synthesizing a biomimeticmaterial inkfor three-dimensional(3D)bioprintingof skeletal tissueis anattractivestrategyfor tissueregeneration.Thus,human bone extracellular matrix(bone-ECM)offers an exciting potential for the development of an appropriate microenvironment for human bone marrow stromal cells(HBMSCs)to proliferate and differentiate along the osteogenic lineage.In this study,we engineered a novel material ink(LAB)by blending human bone-ECM(B)with nanoclay(L,Laponite®)and alginate(A)polymers using extrusion-based deposition.The inclusion of the nanofiller and polymeric material increased the rheology,printability,and drug retention properties and,critically,the preservation of HBMSCs viability upon printing.The composite of human bone-ECM-based 3D constructs containing vascular endothelial growth factor(VEGF)enhanced vascularization after implantation in an ex vivo chick chorioallantoic membrane(CAM)model.The inclusion of bone morphogenetic protein-2(BMP-2)with the HBMSCs further enhanced vascularization and mineralization after only seven days.This study demonstrates the synergistic combination of nanoclay with biomimetic materials(alginate and bone-ECM)to support the formation of osteogenic tissue both in vitro and ex vivo and offers a promising novel 3D bioprinting approach to personalized skeletal tissue repair.
基金the Deanship of Graduate Studies and Scientific Research at Qassim University for financial support(QU-APC-2024-9/1).
文摘The prompt spread of COVID-19 has emphasized the necessity for effective and precise diagnostic tools.In this article,a hybrid approach in terms of datasets as well as the methodology by utilizing a previously unexplored dataset obtained from a private hospital for detecting COVID-19,pneumonia,and normal conditions in chest X-ray images(CXIs)is proposed coupled with Explainable Artificial Intelligence(XAI).Our study leverages less preprocessing with pre-trained cutting-edge models like InceptionV3,VGG16,and VGG19 that excel in the task of feature extraction.The methodology is further enhanced by the inclusion of the t-SNE(t-Distributed Stochastic Neighbor Embedding)technique for visualizing the extracted image features and Contrast Limited Adaptive Histogram Equalization(CLAHE)to improve images before extraction of features.Additionally,an AttentionMechanism is utilized,which helps clarify how the modelmakes decisions,which builds trust in artificial intelligence(AI)systems.To evaluate the effectiveness of the proposed approach,both benchmark datasets and a private dataset obtained with permissions from Jinnah PostgraduateMedical Center(JPMC)in Karachi,Pakistan,are utilized.In 12 experiments,VGG19 showcased remarkable performance in the hybrid dataset approach,achieving 100%accuracy in COVID-19 vs.pneumonia classification and 97%in distinguishing normal cases.Overall,across all classes,the approach achieved 98%accuracy,demonstrating its efficiency in detecting COVID-19 and differentiating it fromother chest disorders(Pneumonia and healthy)while also providing insights into the decision-making process of the models.
文摘Software cost estimation is a crucial aspect of software project management,significantly impacting productivity and planning.This research investigates the impact of various feature selection techniques on software cost estimation accuracy using the CoCoMo NASA dataset,which comprises data from 93 unique software projects with 24 attributes.By applying multiple machine learning algorithms alongside three feature selection methods,this study aims to reduce data redundancy and enhance model accuracy.Our findings reveal that the principal component analysis(PCA)-based feature selection technique achieved the highest performance,underscoring the importance of optimal feature selection in improving software cost estimation accuracy.It is demonstrated that our proposed method outperforms the existing method while achieving the highest precision,accuracy,and recall rates.
文摘The influence of Mo and ZrO_(2)nanoparticles addition on the interfacial properties and shear strength of Sn58Bi solder joint was investigated.The interfacial microstructures of Sn58Bi/Cu,Sn58Bi+Mo/Cu and Sn58Bi+ZrO_(2)/Cu solder joints were analysed using a scanning electron microscope(SEM)coupled with energy dispersive X-ray(EDX)and the X-ray diffraction(XRD).Intermetallic compounds(IMCs)of MoSn_(2)are detected in the Sn58Bi+Mo/Cu solder joint,while SnZr,Zr_(5)Sn_(3),ZrCu and ZrSn_(2)are detected in Sn58Bi+ZrO_(2)/Cu solder joint.IMC layers for both composite solders comprise of Cu_(6)Sn_(5) and Cu_(3)Sn.The SEM images of these layers were used to measure the IMC layer’s thickness.The average IMC layer’s thickness is 1.4431μm for Sn58Bi+Mo/Cu and 0.9112μm for Sn58Bi+ZrO_(2)/Cu solder joints.Shear strength of the solder joints was investigated via the single shear lap test method.The average maximum load and shear stress of the Sn58Bi+Mo/Cu and Sn58Bi+ZrO_(2)/Cu solder joints are increased by 33%and 69%,respectively,as compared to those of the Sn58Bi/Cu solder joint.By comparing both composite solder joints,the latter prevails better as adding smaller sized ZrO_(2)nanoparticles improves the interfacial properties granting a stronger solder joint.
文摘In the increasingly decentralized energy environment,economical power dispatching from distributed generations(DGs)is crucial to minimizing operating costs,optimizing resource utilization,and guaranteeing a consistent and sustainable supply of electricity.A comprehensive review of optimization techniques for economic power dispatching from distributed generations is imperative to identify the most effective strategies for minimizing operational costs while maintaining grid stability and sustainability.The choice of optimization technique for economic power dispatching from DGs depends on a number of factors,such as the size and complexity of the power system,the availability of computational resources,and the specific requirements of the application.Optimization techniques for economic power dispatching from distributed generations(DGs)can be classified into two main categories:(i)Classical optimization techniques,(ii)Heuristic optimization techniques.In classical optimization techniques,the linear programming(LP)model is one of the most popular optimization methods.Utilizing the LP model,power demand and network constraints are met while minimizing the overall cost of generating electricity from DGs.This approach is efficient in determining the best DGs dispatch and is capable of handling challenging optimization issues in the large-scale system including renewables.The quadratic programming(QP)model,a classical optimization technique,is a further popular optimization method,to consider non-linearity.The QP model can take into account the quadratic cost of energy production,with consideration constraints like network capacity,voltage,and frequency.The metaheuristic optimization techniques are also used for economic power dispatching from DGs,which include genetic algorithms(GA),particle swarm optimization(PSO),and ant colony optimization(ACO).Also,Some researchers are developing hybrid optimization techniques that combine elements of classical and heuristic optimization techniques with the incorporation of droop control,predictive control,and fuzzy-based methods.These methods can deal with large-scale systems with many objectives and non-linear,non-convex optimization issues.The most popular approaches are the LP and QP models,while more difficult problems are handled using metaheuristic optimization techniques.In summary,in order to increase efficiency,reduce costs,and ensure a consistent supply of electricity,optimization techniques are essential tools used in economic power dispatching from DGs.
基金supported by the National Natural Science Foundation of China (21908132)。
文摘Phenol-containing wastewater is typical organic wastewater,and its treatment is arduous.An advanced method to treat this type of wastewater is persulfate activation.Environmentally friendly ceriummanganese composite oxide materials were synthesized by hydrothermal method and applied to the phenol degradation process.Various ratios of cerium and manganese,as well as the amount of sodium hydroxide,were investigated.The solid solutions of cerium and manganese were formed and confirmed by X-ray diffraction(XRD) and transmission electron microscopy(TEM).H_(2)-temperature programmed reduction(H_(2)-TPR) and X-ray photoelectron spectroscopy(XPS) were utilized to analyze the synergistic effect of cerium and manganese.It is found that there is a transformation between Ce^(4+)/Ce^(3+) and Mn^(2+)/Mn^(3+),which makes the material more trivalent manganese and thereby increases the catalytic activity.The effect of materials in catalyzing phenol degradation by peroxodisulfate(PDS) under various preparation conditions is discussed and high-effciency removal of phenol can be achieved and the removal rate at 180 min is close to 100%.The kinetic of this process was investigated and activation energy of phenol degradation is 62,35 kJ/mol.The degradation pathway of phenol was studied and it is found that PDS can be activated by low metal ions and the OH and SO_(4·)^(-)radicals play crucial roles according to the quenching experiments.
基金Deanship of Scientific Research at King Khalid University for funding this work through a large group Research Project under Grant Number RGP.2/373/45.
文摘The DNS over HTTPS(Hypertext Transfer Protocol Secure)(DoH)is a new technology that encrypts DNS traffic,enhancing the privacy and security of end-users.However,the adoption of DoH is still facing several research challenges,such as ensuring security,compatibility,standardization,performance,privacy,and increasing user awareness.DoH significantly impacts network security,including better end-user privacy and security,challenges for network security professionals,increasing usage of encrypted malware communication,and difficulty adapting DNS-based security measures.Therefore,it is important to understand the impact of DoH on network security and develop newprivacy-preserving techniques to allowthe analysis of DoH traffic without compromising user privacy.This paper provides an in-depth analysis of the effects of DoH on cybersecurity.We discuss various techniques for detecting DoH tunneling and identify essential research challenges that need to be addressed in future security studies.Overall,this paper highlights the need for continued research and development to ensure the effectiveness of DoH as a tool for improving privacy and security.
文摘COVID-19 pandemic restrictions limited all social activities to curtail the spread of the virus.The foremost and most prime sector among those affected were schools,colleges,and universities.The education system of entire nations had shifted to online education during this time.Many shortcomings of Learning Management Systems(LMSs)were detected to support education in an online mode that spawned the research in Artificial Intelligence(AI)based tools that are being developed by the research community to improve the effectiveness of LMSs.This paper presents a detailed survey of the different enhancements to LMSs,which are led by key advances in the area of AI to enhance the real-time and non-real-time user experience.The AI-based enhancements proposed to the LMSs start from the Application layer and Presentation layer in the form of flipped classroom models for the efficient learning environment and appropriately designed UI/UX for efficient utilization of LMS utilities and resources,including AI-based chatbots.Session layer enhancements are also required,such as AI-based online proctoring and user authentication using Biometrics.These extend to the Transport layer to support real-time and rate adaptive encrypted video transmission for user security/privacy and satisfactory working of AI-algorithms.It also needs the support of the Networking layer for IP-based geolocation features,the Virtual Private Network(VPN)feature,and the support of Software-Defined Networks(SDN)for optimum Quality of Service(QoS).Finally,in addition to these,non-real-time user experience is enhanced by other AI-based enhancements such as Plagiarism detection algorithms and Data Analytics.
基金financed by Coordination for the Improvement of Higher Education Personnel,Brazil(CAPES,https://www.gov.br/capes/pt-br)(accessed on 22 September 2024)Finance Code 001(ESS,FDM)+1 种基金Sao Paulo State Research Support Foundation(FAPESP,https://fapesp.br/)(accessed on 22 September 2024)(CIC,grant number 2015/04660-0)National Council for Scientific and Technological Development(CNPq,https://www.gov.br/cnpq/pt-br)(accessed on 22 September 2024)(grant numbers 308937/2021-0(CIC),306576/2020-1(ECB),and 303099/2022-4(JBP)).
文摘Over the last decade,the oriented strand board(OSB)market presented meaningful growth.However,as a woodbased product,because of its anatomical structure and chemical composition,OSB can be damaged by biodeterioration agents.Given that,the biodeterioration of OSB panels must be investigated to improve its durability.In this way,this work analyses the biological resistance against termites(Cryptotermes brevis and Nasutitermes corniger)of heat-treated OSB panels made with Eucalyptus wood glued with vegetable-based polyurethane-an ecofriendly and sustainable adhesive derived from castor oil.Various panels were produced with different layers compositions(face:core:face of 25:50:25 and 30:40:30)in wood mass proportion and were submitted to postproduction heat treatment(at 175℃ and 200℃)replacing the use of chemical insecticides.The influence of the layers variation and heat treatment temperature were evaluated,and these results were compared with commercial panels(made from pinus wood with insecticide).The results showed that the heat treatment did not improve the resistance against termite attack.However,all the experimental panels presented a satisfactory performance that was compatible with the commercial panels produced with insecticide available in the Brazilian market.The combination of Eucalyptus wood and castor oil adhesive to produce OSB,in any variation of layer composition,demonstrated natural resistance against termite attack compatible with the commercial panels,even without using chemical additives to increase durability.
文摘Mobile and Internet network coverage plays an important role in digital transformation and the exploitation of new services. The evolution of mobile networks from the first generation (1G) to the 5th generation is still a long process. 2G networks have developed the messaging service, which complements the already operational voice service. 2G technology has rapidly progressed to the third generation (3G), incorporating multimedia data transmission techniques. It then progressed to fourth generation (4G) and LTE (Long Term Evolution), increasing the transmission speed to improve 3G. Currently, developed countries have already moved to 5G. In developing countries, including Burundi, a member of the East African Community (ECA) where more than 80% are connected to 2G technologies, 40% are connected to the 3G network and 25% to the 4G network and are not yet connected to the 5G network and then still a process. The objective of this article is to analyze the coverage of 2G, 3G and 4G networks in Burundi. This analysis will make it possible to identify possible deficits in order to reduce the digital divide between connected urban areas and remote rural areas. Furthermore, this analysis will draw the attention of decision-makers to the need to deploy networks and coverage to allow the population to access mobile and Internet services and thus enable the digitalization of the population. Finally, this article shows the level of coverage, the digital divide and an overview of the deployment of base stations (BTS) throughout the country to promote the transformation and digital inclusion of services.
文摘This study evaluates the effects of the initial situation of the site (slope and quality of the soil with its resistance characteristics), building loads, support and drainage/non-drainage on the safety and stability of sloping sites. The objective is to contribute to the stabilization of sloping sites under building loads. Considering a sloping site under building loads in the city of Bujumbura in Burundi facing the problem of instability, an experimental study of the site’s soils is first carried out in the laboratory. Secondly, an analysis by numerical simulation of stability is carried out based on 3 main simulation cases: By first considering an initial situation (unloaded), then a loaded situation without support and a loaded situation with support. The calculation is carried out in a drained state and in an undrained state, with a water table blocked at depth to simulate the reality on the ground. Three buildings of different levels are designed according to the existing buildings and their loads are determined for the loaded case simulations. The results of the analysis thus make it possible to assess the effect on safety and stability of: 1) the slope of the unloaded site and the quality of the soil with its resistance characteristics, 2) the loads of the buildings or their intensive increase, 3) the drained or undrained state of the soil on the site, 4) the support or non-support of the unloaded or loaded, drained or undrained sloping site.
文摘The application of carbon nanomaterials, particularly graphene and carbon nanotubes, in cement-based composites is highly significant. These materials demonstrate the multifunctionality of carbon and offer extensive possibilities for technological advancements. This research analyzes how the integration of graphene into cement-based composites enhances damping and mechanical properties, thereby contributing to the safety and durability of structures. Research on carbon nanomaterials is ongoing and is expected to continue driving innovation across various industrial sectors, promoting the sustainable development of building materials.
文摘This paper conducted experimental studies on the damping and mechanical properties of carbon nanotube-nanosilica-cement composite materials with different carbon nanotube contents. The damping and mechanical properties enhancement mechanisms were analyzed and compared through the porosity structure test, XRD analysis, and scanning electron microscope observation. The results show that the introduction of nanosilica significantly improves the dispersion of carbon nanotubes in the cement matrix. At the same time, the addition of nanosilica not only effectively reduces the critical pore size and average pore size of the cement composite material, but also exhibits good synergistic effects with carbon nanotubes, which can significantly optimize the pore structure. Finally, a rationalization suggestion for the co-doping of nanosilica and carbon nanotubes was given to achieve a significant increase in the flexural strength, compressive strength and loss factor of cement-based materials.
文摘This article explores the comparison between the probability method and the least squares method in the design of linear predictive models. It points out that these two approaches have distinct theoretical foundations and can lead to varied or similar results in terms of precision and performance under certain assumptions. The article underlines the importance of comparing these two approaches to choose the one best suited to the context, available data and modeling objectives.
文摘This study is an extension of the previous work done with ARS-680 Environmental Chamber. Drying is a complex operation that demands much energy and time. Drying is essentially important for preservation of ginger rhizome. Drying of ginger was modeled, and then the effective diffusion coefficient and activation energy were determined. For this purpose, the experiments were done at six levels of varied temperatures: 10°C, 20°C, 30°C, 40°C, 50°C and 60°C. The values of effective diffusion coefficients obtained in this work for the variously treated ginger rhizomes closely agreed with the average effective diffusion coefficients of other notable authors who determined the drying kinetics and convective heat transfer coefficients of ginger slices.
文摘The early collapse of habitats in the spontaneous neighborhoods of the South-East of N’Djamena city pushed us to carry out investigations on the soil characteristics of the Ambatta 1 (Z1), Ambatta 2 (Z2), and Siguété (Z3) neighborhoods in this city. XRF (X-Ray Fluorescence), XRD (X-Ray Diffraction), FTIR (Fourier Transform InfraRed), SEM (Scanning Electron Microscopy), and ATG/DTA (Thermogravimetry Analysis/Differential Thermal Analysis) were conducted for microstructural and thermal identification. The geochemistry of the three soils studied revealed the presence of SiO2 (49.03% - 73.80%), Al2O3 (08.35% - 17.34%), and Fe2O3 (03.79% - 10.90%) as major elements. The alkalines and alkaline earth elements include potassium K2O (02.57% - 03.07%), magnesium MgO (0.47% - 01.21%), titanium TiO2 (0.81% - 01.41%), sodium Na2O (01.01% - 01.13%) and calcium CaO (01.28% - 03.28%). The fire loss of 09.90% on average remains low. XRD revealed the presence of quartz (~64.28%), feldspar (~07.14%), which are non-clay minerals, and clay minerals like kaolinite (~14.85%), illite (~07.14%) and some traces of smectite and amphibite on all three sites. These oxides were confirmed by FTIR analysis through peaks illustrating the vibrational movements specific to these oxides. SEM shows particles in the increasingly shaped, rounded, shiny sand grains. This is the presence of quartz. These quartz micro textures of abrasive surfaces and topography with conchoidal fractures predict promising mechanical results. Smectite appears in wavy clusters, kaolinite in the form of shiny crystals, and illite materializes by the irregularity of the crystalline shape. These constituents are represented by the presence of their oxides specified by geochemistry. Thermally, the three samples overall retain more than 94% of their constituent on average for a temperature range reaching 950˚C, which predestines them for specific applications. Thus, this study aims to stabilize constructions using local materials after having mastered their constituents.
基金Project(12JCYBJC32100)supported by the Tianjin Research Program of Application Foundation and Advanced Technology,ChinaProject([2013]693)supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry,China
文摘Creep and anelastic backflow behaviors of pure copper （4N Cu） with grain size dg=40 μm were investigated at low temperatures of T〈0.3Tm （Tm is melting point） and ultra-low creep rates of ε≤1×10^-10 s^-1 by a high strain-resolution measurement （the helicoid spring specimen technique）. Analysis of creep data was based on the scaling factors of creep curves instead of the conventional extrapolated steady-state creep rate. Power-law creep equation is suggested to be the best for describing the primary transient creep behavior, because the pre-parameter does not apparently change with elapsed time. The observed anelastic strains are 1/6 of the calculated elastic strains, and linear viscous behavior was identified from the logarithm plot of the anelastic strain rate versus anelastic strain （slope equals 1）. Therefore, the creep anelasticity is suggested to be due to the unbowing of there-dimensional network of dislocations.
