The flow shop scheduling problem is important for the manufacturing industry.Effective flow shop scheduling can bring great benefits to the industry.However,there are few types of research on Distributed Hybrid Flow S...The flow shop scheduling problem is important for the manufacturing industry.Effective flow shop scheduling can bring great benefits to the industry.However,there are few types of research on Distributed Hybrid Flow Shop Problems(DHFSP)by learning assisted meta-heuristics.This work addresses a DHFSP with minimizing the maximum completion time(Makespan).First,a mathematical model is developed for the concerned DHFSP.Second,four Q-learning-assisted meta-heuristics,e.g.,genetic algorithm(GA),artificial bee colony algorithm(ABC),particle swarm optimization(PSO),and differential evolution(DE),are proposed.According to the nature of DHFSP,six local search operations are designed for finding high-quality solutions in local space.Instead of randomselection,Q-learning assists meta-heuristics in choosing the appropriate local search operations during iterations.Finally,based on 60 cases,comprehensive numerical experiments are conducted to assess the effectiveness of the proposed algorithms.The experimental results and discussions prove that using Q-learning to select appropriate local search operations is more effective than the random strategy.To verify the competitiveness of the Q-learning assistedmeta-heuristics,they are compared with the improved iterated greedy algorithm(IIG),which is also for solving DHFSP.The Friedman test is executed on the results by five algorithms.It is concluded that the performance of four Q-learning-assisted meta-heuristics are better than IIG,and the Q-learning-assisted PSO shows the best competitiveness.展开更多
The selected modifications to the construction of grinding wheels were described which facilitate an increase in the material removal rate （grinding wheels with conic chamfer and grinding wheels with microdiscontinui...The selected modifications to the construction of grinding wheels were described which facilitate an increase in the material removal rate （grinding wheels with conic chamfer and grinding wheels with microdiscontinuities on the active surface）. Using these background details, a suggested thesis was put forward regarding the need to develop a device which will allow for the shaping of the macrogeometry of the grinding wheel （cylindrical and conical surfaces） and the microdiscontinuities within the dressing operation simultaneously. The device was presented and prepared in two functional variants （horizontal and vertical mounting of the motor）, then a prototype was described. An example of the grinding wheel active surface, shaped by using this device, was also presented. The theoretical analysis and experimental verification performed determine that the error of shaping the conic chamfer angle within the range of 0-1.5°, using the developed device, is approximately ±3%.展开更多
CrN coatings were deposited using cathodic arc evaporation in stationary system on the substrate surface faced to the plasma source and on the back surface.The effect of nitrogen pressure on the structure and phase co...CrN coatings were deposited using cathodic arc evaporation in stationary system on the substrate surface faced to the plasma source and on the back surface.The effect of nitrogen pressure on the structure and phase composition,mechanical and tribological properties of the coatings was investigated.The coating morphology and structure were characterized using SEM and contact profilometry and X-ray diffractometry,respectively.Mechanical properties were studied by nanoindentation.The friction and wear properties of the coatings were investigated by ball-on-disk tribometer.An increase in nitrogen pressure during coating deposition results in phase transformation according to the relation Cr2N→Cr2N+CrN→CrN.The roughness of the coatings deposited on the front side of the substrate is higher than that on the back side,mainly due to larger number of macroparticles.The hardness and elastic modulus are also higher on the front side of the substrate.The adhesion and wear rate of the coatings have an inverse relationship.展开更多
The term polychlorinated biphenyls, or PCBs refers to a class of synthetic organic chemicals that are, to a large degree, chemically inert. PCBs are not found in a nature as a natural compounds and its appearance in n...The term polychlorinated biphenyls, or PCBs refers to a class of synthetic organic chemicals that are, to a large degree, chemically inert. PCBs are not found in a nature as a natural compounds and its appearance in natural environment is connected with unintentional and irresponsible human activity. PCBs have been produced on an industrial scale for more than 50 years and have been exported as chemicals in products to almost every country in the world. PCBs were commonly used as dielectric fluids in transformers and capacitors, in heat transfer and hydraulic systems. Other uses of PCBs included the formulation of lubricating and cutting oils, as plasticizers in paints. Nowadays PCBs are ranked among the compounds called POP （Persistent Organic Pollutants）. This group of hazard removable pollutants includes pesticides, dioxins and furans also. Fishes fished from August 2006 to December 2007 from lakes in north-east Poland： Lafiskie, Kisajno and Niegocin. The investigations were carried out on four fish species： roach, common bream, perch and pike. According to the preliminary mass and length measurements anticipatory treatment were realized. Subsequently fishes were analysed in accordance with National Institute of Hygiene method. According to the investigations results PCBs were found in fish muscular tissues, fished from north-east lakes. PCB level didn＇t exceed the highest acceptable daily dose （4pg-TEQ body mass/day）.展开更多
This paper focuses on cement composites based on waste fine aggregate obtained from hydroclassification all-in-aggregate in the Central Pomerania region in northern Poland. In the world there are regions with poor sup...This paper focuses on cement composites based on waste fine aggregate obtained from hydroclassification all-in-aggregate in the Central Pomerania region in northern Poland. In the world there are regions with poor supplies of coarse aggregate, which is one of the most essential raw materials used for production of ordinary concrete. In these regions, instead of coarse aggregate, there are often very large deposits of fine aggregate such as natural sand and fine all-in-aggregate. These raw materials may be used for concrete production of standard mechanical properties. Manufacturing concrete based on locally available fine aggregate is inexpensive which encourages the local production of fine aggregate cement composites instead of ordinary concrete, requiring gravel transported from distant places.展开更多
This paper presents the characteristics of nickel-based alloys, alongside their division into groups, and describes thefeatures that make such materials difficult to grind. The possibilities of exerting a positive inf...This paper presents the characteristics of nickel-based alloys, alongside their division into groups, and describes thefeatures that make such materials difficult to grind. The possibilities of exerting a positive influence upon machining conditions,especially through the proper application of grinding fluids, are briefly presented. Both the precise methodologies for, and theresults of, the experimental tests carried out on flat surfaces are also detailed. The aim of these tests was to determine the influenceof the application of two types of grinding liquid （Ecocut Mikro Plus 82 and Biocut 3000） upon the grinding force values andsurface roughness of the machined workpieces made from three nickel alloys （Nickel 201, INCONEL~ alloy 600, and MONEL^alloy 400）. An additional goal of the tests was to determine the influence of grinding wheel structure on the course and results ofthe machining process. The results indicate that the physical and chemical properties of Biocut 3000 enabled the most advanta-geous properties of the machined surface roughness, alongside a simultaneous increase in grinding power, when compared to theresults when applying Ecocut Mikro Plus 82. The results showed an almost inversely proportional dependence upon the specifictangential grinding force Ft＇ and arithmetic mean deviation of the surface profile Ra values, especially in cases of machining Nickel201 and INCONEL alloy 600. The original traverse grinding methodology used in the tests made it possible to assess the changesof the grinding conditions within the conventionally selected zones.展开更多
As corona virus disease(COVID-19)is still an ongoing global outbreak,countries around the world continue to take precautions and measures to control the spread of the pandemic.Because of the excessive number of infect...As corona virus disease(COVID-19)is still an ongoing global outbreak,countries around the world continue to take precautions and measures to control the spread of the pandemic.Because of the excessive number of infected patients and the resulting deficiency of testing kits in hospitals,a rapid,reliable,and automatic detection of COVID-19 is in extreme need to curb the number of infections.By analyzing the COVID-19 chest X-ray images,a novel metaheuristic approach is proposed based on hybrid dipper throated and particle swarm optimizers.The lung region was segmented from the original chest X-ray images and augmented using various transformation operations.Furthermore,the augmented images were fed into the VGG19 deep network for feature extraction.On the other hand,a feature selection method is proposed to select the most significant features that can boost the classification results.Finally,the selected features were input into an optimized neural network for detection.The neural network is optimized using the proposed hybrid optimizer.The experimental results showed that the proposed method achieved 99.88%accuracy,outperforming the existing COVID-19 detection models.In addition,a deep statistical analysis is performed to study the performance and stability of the proposed optimizer.The results confirm the effectiveness and superiority of the proposed approach.展开更多
We present an extension of the resource-constrained multi-product scheduling problem for an automated guided vehicle(AGV) served flow shop, where multiple material handling transport modes provide movement of work pie...We present an extension of the resource-constrained multi-product scheduling problem for an automated guided vehicle(AGV) served flow shop, where multiple material handling transport modes provide movement of work pieces between machining centers in the multimodal transportation network(MTN). The multimodal processes behind the multi-product production flow executed in an MTN can be seen as processes realized by using various local periodically functioning processes. The considered network of repetitively acting local transportation modes encompassing MTN's structure provides a framework for multimodal processes scheduling treated in terms of optimization of the AGVs fleet scheduling problem subject to fuzzy operation time constraints. In the considered case, both production takt and operation execution time are described by imprecise data. The aim of the paper is to present a constraint propagation(CP) driven approach to multi-robot task allocation providing a prompt service to a set of routine queries stated in both direct and reverse way. Illustrative examples taking into account an uncertain specification of robots and workers operation time are provided.展开更多
Globally, about one third of all food produced is wasted every year. Losses take place along the entire food chain and they need to be analyzed and monitored due to their impact on the development of the food sector. ...Globally, about one third of all food produced is wasted every year. Losses take place along the entire food chain and they need to be analyzed and monitored due to their impact on the development of the food sector. In addition to quantitative losses, irrational use of food contributes to the depletion of natural resources （water and energy） and poses a threat to the environment, constituting a barrier to sustainable development of the food sector. The aim of this study was to establish the causes and effects of food waste throughout the food supply chain and to propose mitigation measures. Identified causes of food waste can be divided into two groups. The first are those that lead to the fact that food cannot be consumed （e.g., inadequate conditions of agricultural production and interruption of the cold chain）. In the second, those that cause food cannot be sold （e.g., wrong label and wrong product weight）. Most of the identified causes of food waste can be avoided （e.g., by improving the conditions of production, storage, and transportation）. However, it is not possible to eliminate all potential errors leading to food waste. It is therefore necessary to consider what action to take to use food as intended. One way to reduce losses and food waste can be re-distributing to charity.展开更多
The main reason for the high strength in near-βtitanium alloys is the ultrafine precipitation of the acicular secondary a phase in theβmatrix.The purpose of this study is to use the pseudo-spinodal mechanism to obta...The main reason for the high strength in near-βtitanium alloys is the ultrafine precipitation of the acicular secondary a phase in theβmatrix.The purpose of this study is to use the pseudo-spinodal mechanism to obtain the ultrafine a phase for the design of a new high-strength near-γtitanium alloy.Thermodynamic calculations and TC21-(TC21+15 Mo)diffusion couple composition gradient experiments were used to demonstrate that TC21+3 Mo alloy can undergo a pseudo-spinodal decomposition to obtain the ultrafine a phase,resulting in a high-strength alloy.By adjusting the heat treatment process to obtain a bimodal microstructure,the alloy exhibits a good balance between ultimate tensile strength(1351 MPa)and plasticity(8.5%strain).Thus,it was demonstrated that the pseudospinodal mechanism combined with a high-throughput diffusion couple technique is an effective method for designing high-strength titanium alloys.展开更多
Recently,online learning platforms have proven to help people gain knowledge more conveniently.Since the outbreak of COVID-19 in 2020,online learning has become a mainstream mode,as many schools have adopted its forma...Recently,online learning platforms have proven to help people gain knowledge more conveniently.Since the outbreak of COVID-19 in 2020,online learning has become a mainstream mode,as many schools have adopted its format.The platforms are able to capture substantial data relating to the students’learning activities,which could be analyzed to determine relationships between learning behaviors and study habits.As such,an intelligent analysis method is needed to process efficiently this high volume of information.Clustering is an effect data mining method which discover data distribution and hidden characteristic from uncharacterized online learning data.This study proposes a clustering algorithm based on brain storm optimization(CBSO)to categorize students according to their learning behaviors and determine their characteristics.This enables teaching to be tailored to taken into account those results,thereby,improving the education quality over time.Specifically,we use the individual of CBSO to represent the distribution of students and find the optimal one by the operations of convergence and divergence.The experiments are performed on the 104 students’online learning data,and the results show that CBSO is feasible and efficient.展开更多
Nowadays, biomedicine development is caused by the necessity of fast premalignant and malignant diagnosis. In the case of cancer, it is important to identify degree of tumor’s malice. We investigated the differences ...Nowadays, biomedicine development is caused by the necessity of fast premalignant and malignant diagnosis. In the case of cancer, it is important to identify degree of tumor’s malice. We investigated the differences of Fourier Transform Infrared-Attenuated Total Reflection (FTIR-ATR) and FT-Raman spectroscopy between leukoplakia, oral cancer and normal tissues. Human tissue contains many compounds with known absorption spectra in the range of Near Infrared (NIR) spectroscopy. These compounds have a fingerprint region, which permits their characterization. FTIR spectroscopy is a promising diagnostic tool. There is ability to detect skin, cervix, prostate, breast, esophagus, stomach, bladder and oral cancers [1]. Imaging using FTIR microscope allows analysis of biochemical compounds in microregions of biological materials. FTIR microspectroscopy is the perfect technique for tissues and individual cells analysis [1]. It delivers information about biochemistry of cell or tissue samples and has been applied in many areas of medical research [2]. IR absorption spectra of abnormal tissues and normal tissues are compared by lipid (2800 - 3000 cm–1), protein (1500 - 1700 cm–1), and nucleic acids (1000 - 1250 cm–1) regions [2]. One of the mucous membrane lesions of the mouth is leukoplakia. This change has a “fingerprint region” in the range of 900 - 1800 cm–1 [3]. Raman spectroscopy has high potential of medical diagnosis. This method is a molecular specific technique that can be used to develop a fundamental biochemical understanding of tissue physiology and pathology. Both methods are dedicated to screening of preneoplastic and neoplastic tissues and have a potential to reduce morbidity of leucoplakia and oral cancers. Obtained data suggested that these infrared techniques are applicable to biomedical and clinical diagnostics.展开更多
In this article, the results were presented of research concerning the visual and functional aspects of the websites of three largest logistics operators in Poland. The research was carried out with the participation ...In this article, the results were presented of research concerning the visual and functional aspects of the websites of three largest logistics operators in Poland. The research was carried out with the participation of the following three groups： institutional customers, individual customers and marketing management students. The article covers an attempt to evaluate cooperation through virtual contacts with the company. The analysis also concerned such issues as information on corporate social responsibility （CSR）, information on job offers and the position of the company on the market.展开更多
The most important grinding processes were realized in a single pass of the grinding wheel,such as continuous path controlled grinding (CPCG/Peelgrinding/HSP),CPCG with reduced contact of the grinding wheel (Quickpoin...The most important grinding processes were realized in a single pass of the grinding wheel,such as continuous path controlled grinding (CPCG/Peelgrinding/HSP),CPCG with reduced contact of the grinding wheel (Quickpoint),single-pass longitudinal internal grinding,creep feed grinding (CFG),longitudinal cylindrical grinding with grinding wheels made of conventional abrasive materials and longitudinal internal cylindrical grinding using grinding wheels with zone-diversified structure.展开更多
The possibility of applying a high-pressure hydro-jet for renewal of the grinding wheel cutting ability was presented.This work was conducted in the internal cylindrical grinding process of the Titanium Grade 2 alloy,...The possibility of applying a high-pressure hydro-jet for renewal of the grinding wheel cutting ability was presented.This work was conducted in the internal cylindrical grinding process of the Titanium Grade 2 alloy,which belongs to the group of hard-to-cut materials.The analysis shows that the impact on the erosion effectiveness of the grinding wheel active surface(GWAS)depends upon the hydro-jet inclination angle and working pressure.Experimental results reveal that application of hydro-jet working pressure of 25 MPa allows for effective cleansing of the grinding wheel surface.Depending on the initial GWAS condition and the level of its smearing with chips of machined material,it is possible to increase the number of grinding wheel unevenness apexes by as much as 4.5 times.展开更多
基金partially supported by the Guangdong Basic and Applied Basic Research Foundation(2023A1515011531)the National Natural Science Foundation of China under Grant 62173356+2 种基金the Science and Technology Development Fund(FDCT),Macao SAR,under Grant 0019/2021/AZhuhai Industry-University-Research Project with Hongkong and Macao under Grant ZH22017002210014PWCthe Key Technologies for Scheduling and Optimization of Complex Distributed Manufacturing Systems(22JR10KA007).
文摘The flow shop scheduling problem is important for the manufacturing industry.Effective flow shop scheduling can bring great benefits to the industry.However,there are few types of research on Distributed Hybrid Flow Shop Problems(DHFSP)by learning assisted meta-heuristics.This work addresses a DHFSP with minimizing the maximum completion time(Makespan).First,a mathematical model is developed for the concerned DHFSP.Second,four Q-learning-assisted meta-heuristics,e.g.,genetic algorithm(GA),artificial bee colony algorithm(ABC),particle swarm optimization(PSO),and differential evolution(DE),are proposed.According to the nature of DHFSP,six local search operations are designed for finding high-quality solutions in local space.Instead of randomselection,Q-learning assists meta-heuristics in choosing the appropriate local search operations during iterations.Finally,based on 60 cases,comprehensive numerical experiments are conducted to assess the effectiveness of the proposed algorithms.The experimental results and discussions prove that using Q-learning to select appropriate local search operations is more effective than the random strategy.To verify the competitiveness of the Q-learning assistedmeta-heuristics,they are compared with the improved iterated greedy algorithm(IIG),which is also for solving DHFSP.The Friedman test is executed on the results by five algorithms.It is concluded that the performance of four Q-learning-assisted meta-heuristics are better than IIG,and the Q-learning-assisted PSO shows the best competitiveness.
文摘The selected modifications to the construction of grinding wheels were described which facilitate an increase in the material removal rate （grinding wheels with conic chamfer and grinding wheels with microdiscontinuities on the active surface）. Using these background details, a suggested thesis was put forward regarding the need to develop a device which will allow for the shaping of the macrogeometry of the grinding wheel （cylindrical and conical surfaces） and the microdiscontinuities within the dressing operation simultaneously. The device was presented and prepared in two functional variants （horizontal and vertical mounting of the motor）, then a prototype was described. An example of the grinding wheel active surface, shaped by using this device, was also presented. The theoretical analysis and experimental verification performed determine that the error of shaping the conic chamfer angle within the range of 0-1.5°, using the developed device, is approximately ±3%.
文摘CrN coatings were deposited using cathodic arc evaporation in stationary system on the substrate surface faced to the plasma source and on the back surface.The effect of nitrogen pressure on the structure and phase composition,mechanical and tribological properties of the coatings was investigated.The coating morphology and structure were characterized using SEM and contact profilometry and X-ray diffractometry,respectively.Mechanical properties were studied by nanoindentation.The friction and wear properties of the coatings were investigated by ball-on-disk tribometer.An increase in nitrogen pressure during coating deposition results in phase transformation according to the relation Cr2N→Cr2N+CrN→CrN.The roughness of the coatings deposited on the front side of the substrate is higher than that on the back side,mainly due to larger number of macroparticles.The hardness and elastic modulus are also higher on the front side of the substrate.The adhesion and wear rate of the coatings have an inverse relationship.
文摘The term polychlorinated biphenyls, or PCBs refers to a class of synthetic organic chemicals that are, to a large degree, chemically inert. PCBs are not found in a nature as a natural compounds and its appearance in natural environment is connected with unintentional and irresponsible human activity. PCBs have been produced on an industrial scale for more than 50 years and have been exported as chemicals in products to almost every country in the world. PCBs were commonly used as dielectric fluids in transformers and capacitors, in heat transfer and hydraulic systems. Other uses of PCBs included the formulation of lubricating and cutting oils, as plasticizers in paints. Nowadays PCBs are ranked among the compounds called POP （Persistent Organic Pollutants）. This group of hazard removable pollutants includes pesticides, dioxins and furans also. Fishes fished from August 2006 to December 2007 from lakes in north-east Poland： Lafiskie, Kisajno and Niegocin. The investigations were carried out on four fish species： roach, common bream, perch and pike. According to the preliminary mass and length measurements anticipatory treatment were realized. Subsequently fishes were analysed in accordance with National Institute of Hygiene method. According to the investigations results PCBs were found in fish muscular tissues, fished from north-east lakes. PCB level didn＇t exceed the highest acceptable daily dose （4pg-TEQ body mass/day）.
文摘This paper focuses on cement composites based on waste fine aggregate obtained from hydroclassification all-in-aggregate in the Central Pomerania region in northern Poland. In the world there are regions with poor supplies of coarse aggregate, which is one of the most essential raw materials used for production of ordinary concrete. In these regions, instead of coarse aggregate, there are often very large deposits of fine aggregate such as natural sand and fine all-in-aggregate. These raw materials may be used for concrete production of standard mechanical properties. Manufacturing concrete based on locally available fine aggregate is inexpensive which encourages the local production of fine aggregate cement composites instead of ordinary concrete, requiring gravel transported from distant places.
文摘This paper presents the characteristics of nickel-based alloys, alongside their division into groups, and describes thefeatures that make such materials difficult to grind. The possibilities of exerting a positive influence upon machining conditions,especially through the proper application of grinding fluids, are briefly presented. Both the precise methodologies for, and theresults of, the experimental tests carried out on flat surfaces are also detailed. The aim of these tests was to determine the influenceof the application of two types of grinding liquid （Ecocut Mikro Plus 82 and Biocut 3000） upon the grinding force values andsurface roughness of the machined workpieces made from three nickel alloys （Nickel 201, INCONEL~ alloy 600, and MONEL^alloy 400）. An additional goal of the tests was to determine the influence of grinding wheel structure on the course and results ofthe machining process. The results indicate that the physical and chemical properties of Biocut 3000 enabled the most advanta-geous properties of the machined surface roughness, alongside a simultaneous increase in grinding power, when compared to theresults when applying Ecocut Mikro Plus 82. The results showed an almost inversely proportional dependence upon the specifictangential grinding force Ft＇ and arithmetic mean deviation of the surface profile Ra values, especially in cases of machining Nickel201 and INCONEL alloy 600. The original traverse grinding methodology used in the tests made it possible to assess the changesof the grinding conditions within the conventionally selected zones.
文摘As corona virus disease(COVID-19)is still an ongoing global outbreak,countries around the world continue to take precautions and measures to control the spread of the pandemic.Because of the excessive number of infected patients and the resulting deficiency of testing kits in hospitals,a rapid,reliable,and automatic detection of COVID-19 is in extreme need to curb the number of infections.By analyzing the COVID-19 chest X-ray images,a novel metaheuristic approach is proposed based on hybrid dipper throated and particle swarm optimizers.The lung region was segmented from the original chest X-ray images and augmented using various transformation operations.Furthermore,the augmented images were fed into the VGG19 deep network for feature extraction.On the other hand,a feature selection method is proposed to select the most significant features that can boost the classification results.Finally,the selected features were input into an optimized neural network for detection.The neural network is optimized using the proposed hybrid optimizer.The experimental results showed that the proposed method achieved 99.88%accuracy,outperforming the existing COVID-19 detection models.In addition,a deep statistical analysis is performed to study the performance and stability of the proposed optimizer.The results confirm the effectiveness and superiority of the proposed approach.
文摘We present an extension of the resource-constrained multi-product scheduling problem for an automated guided vehicle(AGV) served flow shop, where multiple material handling transport modes provide movement of work pieces between machining centers in the multimodal transportation network(MTN). The multimodal processes behind the multi-product production flow executed in an MTN can be seen as processes realized by using various local periodically functioning processes. The considered network of repetitively acting local transportation modes encompassing MTN's structure provides a framework for multimodal processes scheduling treated in terms of optimization of the AGVs fleet scheduling problem subject to fuzzy operation time constraints. In the considered case, both production takt and operation execution time are described by imprecise data. The aim of the paper is to present a constraint propagation(CP) driven approach to multi-robot task allocation providing a prompt service to a set of routine queries stated in both direct and reverse way. Illustrative examples taking into account an uncertain specification of robots and workers operation time are provided.
文摘Globally, about one third of all food produced is wasted every year. Losses take place along the entire food chain and they need to be analyzed and monitored due to their impact on the development of the food sector. In addition to quantitative losses, irrational use of food contributes to the depletion of natural resources （water and energy） and poses a threat to the environment, constituting a barrier to sustainable development of the food sector. The aim of this study was to establish the causes and effects of food waste throughout the food supply chain and to propose mitigation measures. Identified causes of food waste can be divided into two groups. The first are those that lead to the fact that food cannot be consumed （e.g., inadequate conditions of agricultural production and interruption of the cold chain）. In the second, those that cause food cannot be sold （e.g., wrong label and wrong product weight）. Most of the identified causes of food waste can be avoided （e.g., by improving the conditions of production, storage, and transportation）. However, it is not possible to eliminate all potential errors leading to food waste. It is therefore necessary to consider what action to take to use food as intended. One way to reduce losses and food waste can be re-distributing to charity.
基金financially supported by the National Key Technologies R&D Program of China(No.2016YFB0701301)the National Natural Science Foundation of China(Nos.51901251,51671218 and 51501229)the State Key Laboratory of Powder Metallurgy Independent Project of China(No.621021907)。
文摘The main reason for the high strength in near-βtitanium alloys is the ultrafine precipitation of the acicular secondary a phase in theβmatrix.The purpose of this study is to use the pseudo-spinodal mechanism to obtain the ultrafine a phase for the design of a new high-strength near-γtitanium alloy.Thermodynamic calculations and TC21-(TC21+15 Mo)diffusion couple composition gradient experiments were used to demonstrate that TC21+3 Mo alloy can undergo a pseudo-spinodal decomposition to obtain the ultrafine a phase,resulting in a high-strength alloy.By adjusting the heat treatment process to obtain a bimodal microstructure,the alloy exhibits a good balance between ultimate tensile strength(1351 MPa)and plasticity(8.5%strain).Thus,it was demonstrated that the pseudospinodal mechanism combined with a high-throughput diffusion couple technique is an effective method for designing high-strength titanium alloys.
基金This work was partially supported by the National Natural Science Foundation of China(61876089,61876185,61902281,61375121)the Opening Project of Jiangsu Key Laboratory of Data Science and Smart Software(No.2019DS301)+1 种基金the Engineering Research Center of Digital Forensics,Ministry of Education,the Key Research and Development Program of Jiangsu Province(BE2020633)the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Recently,online learning platforms have proven to help people gain knowledge more conveniently.Since the outbreak of COVID-19 in 2020,online learning has become a mainstream mode,as many schools have adopted its format.The platforms are able to capture substantial data relating to the students’learning activities,which could be analyzed to determine relationships between learning behaviors and study habits.As such,an intelligent analysis method is needed to process efficiently this high volume of information.Clustering is an effect data mining method which discover data distribution and hidden characteristic from uncharacterized online learning data.This study proposes a clustering algorithm based on brain storm optimization(CBSO)to categorize students according to their learning behaviors and determine their characteristics.This enables teaching to be tailored to taken into account those results,thereby,improving the education quality over time.Specifically,we use the individual of CBSO to represent the distribution of students and find the optimal one by the operations of convergence and divergence.The experiments are performed on the 104 students’online learning data,and the results show that CBSO is feasible and efficient.
文摘Nowadays, biomedicine development is caused by the necessity of fast premalignant and malignant diagnosis. In the case of cancer, it is important to identify degree of tumor’s malice. We investigated the differences of Fourier Transform Infrared-Attenuated Total Reflection (FTIR-ATR) and FT-Raman spectroscopy between leukoplakia, oral cancer and normal tissues. Human tissue contains many compounds with known absorption spectra in the range of Near Infrared (NIR) spectroscopy. These compounds have a fingerprint region, which permits their characterization. FTIR spectroscopy is a promising diagnostic tool. There is ability to detect skin, cervix, prostate, breast, esophagus, stomach, bladder and oral cancers [1]. Imaging using FTIR microscope allows analysis of biochemical compounds in microregions of biological materials. FTIR microspectroscopy is the perfect technique for tissues and individual cells analysis [1]. It delivers information about biochemistry of cell or tissue samples and has been applied in many areas of medical research [2]. IR absorption spectra of abnormal tissues and normal tissues are compared by lipid (2800 - 3000 cm–1), protein (1500 - 1700 cm–1), and nucleic acids (1000 - 1250 cm–1) regions [2]. One of the mucous membrane lesions of the mouth is leukoplakia. This change has a “fingerprint region” in the range of 900 - 1800 cm–1 [3]. Raman spectroscopy has high potential of medical diagnosis. This method is a molecular specific technique that can be used to develop a fundamental biochemical understanding of tissue physiology and pathology. Both methods are dedicated to screening of preneoplastic and neoplastic tissues and have a potential to reduce morbidity of leucoplakia and oral cancers. Obtained data suggested that these infrared techniques are applicable to biomedical and clinical diagnostics.
文摘In this article, the results were presented of research concerning the visual and functional aspects of the websites of three largest logistics operators in Poland. The research was carried out with the participation of the following three groups： institutional customers, individual customers and marketing management students. The article covers an attempt to evaluate cooperation through virtual contacts with the company. The analysis also concerned such issues as information on corporate social responsibility （CSR）, information on job offers and the position of the company on the market.
文摘The most important grinding processes were realized in a single pass of the grinding wheel,such as continuous path controlled grinding (CPCG/Peelgrinding/HSP),CPCG with reduced contact of the grinding wheel (Quickpoint),single-pass longitudinal internal grinding,creep feed grinding (CFG),longitudinal cylindrical grinding with grinding wheels made of conventional abrasive materials and longitudinal internal cylindrical grinding using grinding wheels with zone-diversified structure.
文摘The possibility of applying a high-pressure hydro-jet for renewal of the grinding wheel cutting ability was presented.This work was conducted in the internal cylindrical grinding process of the Titanium Grade 2 alloy,which belongs to the group of hard-to-cut materials.The analysis shows that the impact on the erosion effectiveness of the grinding wheel active surface(GWAS)depends upon the hydro-jet inclination angle and working pressure.Experimental results reveal that application of hydro-jet working pressure of 25 MPa allows for effective cleansing of the grinding wheel surface.Depending on the initial GWAS condition and the level of its smearing with chips of machined material,it is possible to increase the number of grinding wheel unevenness apexes by as much as 4.5 times.
