A special experiment setup was designed to observe the interaction between bubbles and particle in flotation cell and to analyze the bubble characteristics such as bubble size, distribution and bubble-loading efficien...A special experiment setup was designed to observe the interaction between bubbles and particle in flotation cell and to analyze the bubble characteristics such as bubble size, distribution and bubble-loading efficiency. Bubbles in water-gas system and three-phase system were measured. The results indicate that with the current setup the bubbles as small as 10 μm can be easily distinguished. The average size of the bubbles generated under the given conditions in two-phase system is 410 μm at frother concentration of 0.004%, which is in good correspondence with the results of other works. The effect of frother on bubble size was probed. Increasing frother concentration from 0 to 0.004% causes a reduction of bubble size from 700 to 400 μm. The bubble loading efficiency was reported. The result indicates that the fine particle is more easily entrapped than the coarse particle. Some factors, which have effect on measurement accuracy were discussed. The aeration speed has a significant effect on the accuracy of results, if it surpasses 30 mL/s, and the image becomes unclear due to the entrapment of fine particle. Another factor, which can affect observing results, is the sampling position. At a wrong sampling position, the images become unclear.展开更多
A trajectory imaging based method for measuring the velocity and diameter of coal particles was presented.By using an industrial charge-coupled device(CCD)camera and a low power semiconductor laser,the images of coal ...A trajectory imaging based method for measuring the velocity and diameter of coal particles was presented.By using an industrial charge-coupled device(CCD)camera and a low power semiconductor laser,the images of coal particles under relatively long exposure time were recorded and then processed to yield both the velocities and sizes.Fundamental research on this method with special attention to recording parameters,e.g.,magnification factor and exposure time,was carried out.For most of the test cases,the results agree with those obtained by particle image velocimetry(PIV)and shadow imaging method.Measurements with good accuracy can be obtained when the imaging magnification factor and exposure time are set appropriately,making N be larger than 3.5,and R between 5-7,where N and R are the number of pixels occupied by the average width and the ratio of length to width of particle trajectory on the image,respectively.The work indicates the feasibility and potential application of the present measurement method for online measurement of coal powder in pipes in industrial power plants.展开更多
The use of functional size measurement(FSM) methods in software development organizations is growing during the years. Also, object oriented(OO) techniques have become quite a standard to design the software and, in p...The use of functional size measurement(FSM) methods in software development organizations is growing during the years. Also, object oriented(OO) techniques have become quite a standard to design the software and, in particular, Use Cases is one of the most used techniques to specify functional requirements. Main FSM methods do not include specific rules to measure the software functionality from its Use Cases analysis. To deal with this issue some other methods like Kramer's functional measurement method have been developed. Therefore, one of the main issues for those organizations willing to use OO functional measurement method in order to facilitate the use cases count procedure is how to convert their portfolio functional size from the previously adopted FSM method towards the new method. The objective of this research is to find a statistical relationship for converting the software functional size units measured by the International Function Point Users Group(IFPUG) function point analysis(FPA) method into Kramer-Smith's use cases points(UCP) method and vice versa. Methodologies for a correct data gathering are proposed and results obtained are analyzed to draw the linear and non-linear equations for this correlation. Finally, a conversion factor and corresponding conversion intervals are given to establish the statistical relationship.展开更多
In this study,the particle size-resolved distribution from a China-3 certificated light-duty diesel vehicle was measured by using a portable emission measurement system（PEMS）.In order to examine the influences of ve...In this study,the particle size-resolved distribution from a China-3 certificated light-duty diesel vehicle was measured by using a portable emission measurement system（PEMS）.In order to examine the influences of vehicle specific power（VSP） and high-altitude operation,measurements were conducted at 8 constant speeds,which ranged from 10 to 80 km/hr at10 km/hr intervals,and two different high altitudes,namely 2200 and 3200 m.The results demonstrated that the numbers of particles in all size ranges decreased significantly as VSP increased when the test vehicle was running at lower speeds（〈 20 km/hr）,while at a moderate speed（between 30 and 60 km/hr）,the particle number was statistically insensitive to increase VSP.Under high-speed cruising conditions,the numbers of ultrafine particles and PM2.5were insensitive to changes in VSP,but the numbers of nanoparticles and PM10 surged considerably.An increase in the operational altitude of the test vehicle resulted in increased particle number emissions at low and high driving speeds;however,particle numbers obtained at moderate speeds decreased as altitude rose.When the test vehicle was running at moderate speeds,particle numbers measured at the two altitudes were very close,except for comparatively higher number concentrations of nanoparticles measured at 2200 m.展开更多
Operations in assembling and joining large size aircraft components are changed to novel digital and flexible ways by digital measurement assisted alignment.Positions and orientations（P＆O）of aligned components are ...Operations in assembling and joining large size aircraft components are changed to novel digital and flexible ways by digital measurement assisted alignment.Positions and orientations（P＆O）of aligned components are critical characters which assure geometrical positions and relationships of those components.Therefore,evaluating the P＆O of a component is considered necessary and critical for ensuring accuracy in aircraft assembly.Uncertainty of position and orientation（U-P＆O）,as a part of the evaluating result of P＆O,needs to be given for ensuring the integrity and credibility of the result;furthermore,U-P＆O is necessary for error tracing and quality evaluating of measurement assisted aircraft assembly.However,current research mainly focuses on the process integration of measurement with assembly,and usually ignores the uncertainty of measured result and its influence on quality evaluation.This paper focuses on the expression,analysis,and application of U-P＆O in measurement assisted alignment.The geometrical and algebraical connotations of U-P＆O are presented.Then,an analytical algorithm for evaluating the multi-dimensional U-P＆O is given,and the effect factors and characteristics of U-P＆O are discussed.Finally,U-P＆O is used to evaluate alignment in aircraft assembly for quality evaluating and improving.Cases are introduced with the methodology.展开更多
The objective of this work is using the online measurement method to study the process of precipitation of nickel hydroxide in a single-feed semi-batch stirred reactor with an internal diameter ofD = 240mm. The effect...The objective of this work is using the online measurement method to study the process of precipitation of nickel hydroxide in a single-feed semi-batch stirred reactor with an internal diameter ofD = 240mm. The effects of impeller speed, impeller type, impeller diameter and feed location on the mean particle size d43 and particle size distribution （PSD） were investigated, d43 and PSD were measured online using a Malvern Insitec Liquid Pro- cess Sizer every 20 s. It was found that d43 varied between 13 kwh and 26 lain under different operating conditions, and it decreased with increasing impeller diameter. When feeding at the off-bottom distance of D/2 under lower impeller speeds, d43 was significantly smaller than that at D/3. PSDs were slightly influenced by operating conditions.展开更多
A quantitative protocol for the rapid analysis of Microcystis cells and colonies in lake sediment was developed using a modified flow cytometer, the CytoSense. For cell enumeration, diluted sediment samples containing...A quantitative protocol for the rapid analysis of Microcystis cells and colonies in lake sediment was developed using a modified flow cytometer, the CytoSense. For cell enumeration, diluted sediment samples containing Microcystis were processed with sonication to disintegrate colonies into single cells. An optimized procedure suggested that 5 mg dw （dry weight）/mL dilution combined with 200 W x 2 min sonication yielded the highest counting efficiency. Under the optimized determination conditions, the quantification limit of this protocol was 3.3x104 cells/g dw. For colony analysis, Microcystis were isolated from the sediment by filtration. Colony lengths measured by flow cytometry were similar to those measured by microscopy for the size range of one single cell to almost 400 ~tm in length. Moreover, the relationship between colony size and cell number was determined for three Microcystis species, including Microcystisflos-aquae, M. aeruginosa and M. wessenbergii. Regression formulas were used to calculate the cell numbers in different- sized colonies. The developed protocol was applied to field sediment samples from Lake Taihu. The results indicated the potential and applicability of flow cytometry as a tool for the rapid analysis of benthic Microcystis. This study provided a new capability for the high frequency monitoring of benthic overwintering and population dynamics of this bloom-forming cyanobacterium.展开更多
The growing characteristics of metallic iron particles during reductive roasting of boron-bearing magnetite concentrate under different conditions were investigated.The size of the metallic iron particles was quantita...The growing characteristics of metallic iron particles during reductive roasting of boron-bearing magnetite concentrate under different conditions were investigated.The size of the metallic iron particles was quantitatively measured via optical image analysis with consideration of size calibration and weighted ratio of image numbers in the core,middle and periphery zones of cross-section of pellets.In order to guarantee the measurement accuracy,54 images were captured in total for each specimen,with a weighted ratio of 1:7:19 with respect to the core,middle and periphery section of the cross-section of pellets.Increasing reduction temperature and time is favorable to the growth of metallic iron particles.Based on the modification of particle size measurement,in terms of time(t)and temperature(T)a predicting model of metallic iron particle size(D),was established as:D=125−0.112t−0.2352T−5.355×10^−4t^2+2.032×10^−4t∙T+1.134×10^−4T^2.展开更多
In the software engineering literature, it is commonly believed that economies of scale do not occur in case of software Development and Enhancement Projects （D＆EP）. Their per-unit cost does not decrease but increa...In the software engineering literature, it is commonly believed that economies of scale do not occur in case of software Development and Enhancement Projects （D＆EP）. Their per-unit cost does not decrease but increase with the growth of such projects product size. Thus this is diseconomies of scale that occur in them. The significance of this phenomenon results from the fact that it is commonly considered to be one of the fundamental objective causes of their low effectiveness. This is of particular significance with regard to Business Software Systems （BSS） D＆EP characterized by exceptionally low effectiveness comparing to other software D＆EP. Thus the paper aims at answering the following two questions： （1） Do economies of scale really not occur in BSS D＆EP？ （2） If economies of scale may occur in BSS D＆EP, what factors are then promoting them？ These issues classify into economics problems of software engineering research and practice.展开更多
[ Objective ] The paper was to study growth and physical structure of Holstein cows at specific phase under intensive rearing conditions in the South China. [ Method] The body sizes of 279 Holstein cows including 49 c...[ Objective ] The paper was to study growth and physical structure of Holstein cows at specific phase under intensive rearing conditions in the South China. [ Method] The body sizes of 279 Holstein cows including 49 calves, 35 young cows and 195 adult cows in the experimental farm of Yangzhou University were measured. The raw data were processed by computer to obtain body size index at various physiological stages. The body size indexes were analyzed by SPSS 15.0 software to reflect changes in different physiological stages and various parities of cows. Body size indexes such as body height, body length and heart girth of young cows and calves were fitted by scatter plot. [ Result] The eider the cows were, the longer their bodies were. Calves had a stable growth and development. The body size of young cow at different month-ages was imbalanced. The physical structure of adult cows showed no regularity at different parities, so the specific feeding for growth and development of bone should be strengthened in multiparous cows. [ Conclusion] The study provides reference for keeping management of calves, breeding and keeping management of young cows as well as selection and assortative mating of adult cows.展开更多
In this work,four samples of TiO_(2) powder materials with different structures(rutile,anatase),surface coatings and morphologies(rod,pseudo-spherical)were characterized by four partners involving complementary method...In this work,four samples of TiO_(2) powder materials with different structures(rutile,anatase),surface coatings and morphologies(rod,pseudo-spherical)were characterized by four partners involving complementary methods.With the aim of producing inter-laboratory reproducibility data,the specific surface-area,bulk density,and number size distribution were measured,yielding a satisfying agreement between partners.The equivalent diameter of constituent particles was determined from the sample volume specific surface area(VSSA)–accounting for polydispersion–and compared to electron microscopy(EM).Constituent particle diameters ranged from 15 to 225 nm according to EM analyses.The relative discrepancies between VSSA-based and EM-based diameters were found within±20%.Out of the four samples under study,TiO_(2)μ-rutile leads to a larger deviation,which was attributed to surface coating thanks to complementary analysis.Assuming that the sample is pure,an equivalent diameter based on the VSSA can be determined,provided that the shape of constituent particles is known or supposed.展开更多
We present the spot size dependence of dielectric multilayer filters for use in dense WDM systems. We found large dependences of filter performances on the spot size and the incident angle of input light, which should...We present the spot size dependence of dielectric multilayer filters for use in dense WDM systems. We found large dependences of filter performances on the spot size and the incident angle of input light, which should be important for miniaturizing multi-channel add/drop filters.展开更多
A modified regularization algorithm with a more proper operator was proposed for the inversion of particle size distribution （PSD） from light-scattering data in a laser particle sizer based on the Mie scattering pri...A modified regularization algorithm with a more proper operator was proposed for the inversion of particle size distribution （PSD） from light-scattering data in a laser particle sizer based on the Mie scattering principle. The Generalized Cross-Validation （GCV） method and the L-curve method were used for deter- mining the regularization parameter. The Successive Over-Relaxation （SOR） iterative method was used to increase the exactness and stability of the converged result. The simulated results based on the modified algorithm are in a good agreement with the experimental data measured for nine standard particulate samples, their mixtures as well as three natural particulate materials with irregular shapes, indicating that this modified regularization method is not only feasible but also effective for the simulation of PSD from corresponding light-scattering data.展开更多
The scaffold pore size influences many critical physical aspects of tissue engineering,including tissue infiltration,biodegradation rate,and mechanical properties.Manual measurements of pore sizes from scanning electr...The scaffold pore size influences many critical physical aspects of tissue engineering,including tissue infiltration,biodegradation rate,and mechanical properties.Manual measurements of pore sizes from scanning electron micrographs using ImageJ/FIJI are commonly used to characterize scaffolds,but these methods are both time-consuming and subject to user bias.Current semi-automated analysis tools are limited by a lack of accessibility or limited sample size in their verification process.The work here describes the development of a new MATLAB algorithm,PoreScript,to address these limitations.The algorithm was verified using three common scaffold fabrication methods(e.g.,salt leaching,gas foaming,emulsion templating)with varying pore sizes and shapes to demonstrate the versatility of this new tool.Our results demonstrate that the pore size characterization using PoreScript is comparable to manual pore size measurements.The PoreScript algorithm was further evaluated to determine the effect of user-input and image parameters(relative image magnification,pixel intensity threshold,and pore structure).Overall,this work validates the accuracy of the PoreScript algorithm across several fabrication methods and provides user-guidance for semi-automated image analysis and increased throughput of scaffold characterization.展开更多
As the main use of TBM(tunnel boring machine)cutter ring(DC53 steel)currently is difficult to meet the requirements of high wear resistance and high toughness synchronously in its service environment,a new HWR0 steel ...As the main use of TBM(tunnel boring machine)cutter ring(DC53 steel)currently is difficult to meet the requirements of high wear resistance and high toughness synchronously in its service environment,a new HWR0 steel with 4%Cr-3%V for TBM cutter ring has been developed to control carbides in steel.Precipitation behavior of carbides in HWR0 steel was investigated through theoretical calculation by Thermo-Calc and experimental measurement using scanning electron microscope,energy dispersive spectrometer,electron probe X-ray micro-analyzer,and laser particle size analyzer.The results show that three different carbides are precipitated during cooling.And the as-cast electroslag remelting ingot of HWR0 steel primarily consists of many blocky or strip-like MC distributed along grain boundaries,few chrysanthemum-like M_(6)C concentrated at grain boundary intersections,and a large quantity of fine M_(23)C_(6)and M_(6)C dispersed in the matrix.Compared with DC53 steel,HWR0 steel has more high-hardness carbides MC,which are discontinuously distributed at the grain boundaries,achieving the dual improvement of wear resistance and impact toughness.Cooling rates significantly influence the carbides distribution and grain size.A slower cooling rate exacerbates the segregation of alloying elements,which leads to the localized enrichment of Mo and the subsequent precipitation of M_(6)C carbides at grain boundary intersections.In contrast,faster cooling rate decreases the element segregation,promotes carbide nucleation and limits the space for carbides growth,which results in finer size and distribution of carbides and grains.Higher cooling rates yield a more homogeneous microstructure with uniform MC compositions and promote the preferential formation of M_(6)C carbides along grain boundaries,which enhances the mechanical properties.展开更多
Size distributions of ambient aerosols at the Fresno Supersite were measured with four commercially available scanning mobility particle sizers （SMPS）. TSI nano, TSI standard, Grimm, and MSP instruments were colloca...Size distributions of ambient aerosols at the Fresno Supersite were measured with four commercially available scanning mobility particle sizers （SMPS）. TSI nano, TSI standard, Grimm, and MSP instruments were collocated at the Fresno Supersite and particle size distributions were measured continuously from August 18 through September 18, 2005. For particles with diameters between 10 and 200 nm, differences among hourly-average ambient particle concentrations ranged from 0% between the TSI nano and Grimm in the 30-50 nm size range to 39% between the Grimm and MSP in the 10-30 nm size range. MSP concentrations were 10-33% lower than those measured with the TSI standard for particles smaller than 200 nm. The TSI nano and TSI standard agreed to within 5% in their overlapping size range （10-84 nm）. The TSI nano and Grimm agreed to within 40% for 5-10 nm particles.展开更多
How do you measure the size of a one-dimensional figure?The size of a line segment is given by its length.How do you measure the size of two-dimensional figures?Rectangles and other polygons are two-dimensional.There ...How do you measure the size of a one-dimensional figure?The size of a line segment is given by its length.How do you measure the size of two-dimensional figures?Rectangles and other polygons are two-dimensional.There are two common ways of measuring these figures.Perimeter measures the boundary.Area measures the space inside the figure.展开更多
There are three different common w(?)measure the size of a three dimensional figure. Consider the shoe box below. We can measure the total length of its edges. Like perimeter, this is one-dimensional. We can measure i...There are three different common w(?)measure the size of a three dimensional figure. Consider the shoe box below. We can measure the total length of its edges. Like perimeter, this is one-dimensional. We can measure its surface area,which is two-dimensional. Or we can measure its volume,which is three-dimensional. The shoebox has edges of lengths 14inches,5inches,and 7inches, There are four edges of each length. (some are hidden from view.)The total length of all edges is 4·15"+4·7"+4·14",or 104inches.展开更多
Pig body measurement is an important evaluation criterion for breeding and production management.Automatic measurement algorithms for pig body sizes exhibit sensitivity to the point cloud posture,but non-standard pig ...Pig body measurement is an important evaluation criterion for breeding and production management.Automatic measurement algorithms for pig body sizes exhibit sensitivity to the point cloud posture,but non-standard pig postures may result in inaccurate joint point localization in body measurement,further affecting measurement accuracy and the commercial application of these algorithms.To address this challenge,this paper proposed a pig point cloud posture transformation method based on pig’s skeleton model to adjust non-standard postures before conducting body size measurements.The method utilized an improved L1-median skeleton model to extract the three-dimensional skeleton of the pig point cloud,capturing the skeleton joint points on the target pig’s head,body,and limbs.By binding the skeleton joint points with the local point cloud and using rotation matrices,non-standard postures were adjusted to standard ones,enabling accurate body size measurements.The experimental results demonstrated that the average relative errors between the transferred posture and the original standard posture were reduced to 0.89%in body length,0.76%in body width(front),1%in body width(back),0.89%in body height(front),1.7%in body height(back),2.03%in thoracic circumference,3.37%in abdominal circumference,and 1.89%in rump circumference.To conclude,the posture standardization transfer method can significantly reduce errors in important body size parameters such as body length,body height,and body width.The method displays a greater stability and robustness compared to existing posture normalization and regression adjustment methods,providing both guidance and insight for future research in intelligent agriculture.展开更多
A pinhole camera for imaging X-ray synchrotron radiation from a dipole magnet is now in operation at the Shanghai Synchrotron Radiation Facility （SSRF） storage ring.The electron beam size is derived by unfolding the...A pinhole camera for imaging X-ray synchrotron radiation from a dipole magnet is now in operation at the Shanghai Synchrotron Radiation Facility （SSRF） storage ring.The electron beam size is derived by unfolding the radiation image and the point spread function （PSF） with deconvolution techniques.The performance of the pinhole is determined by the accuracy of the PSF measurement.This article will focus on a beam-based calibration scheme to measure the PSF system by varying the beam images with different quadrupole settings and fitting them with the corresponding theoretical beam sizes.Applying this method at SSRF,the PSF value of the pinhole is revised from 37 to 44μm.The deviation in beam size between the theoretical value and the measured value isminimized to 4% after calibration.This optimization allows us to observe the horizontal disturbance due to injection down to as small as 0.5μm.展开更多
文摘A special experiment setup was designed to observe the interaction between bubbles and particle in flotation cell and to analyze the bubble characteristics such as bubble size, distribution and bubble-loading efficiency. Bubbles in water-gas system and three-phase system were measured. The results indicate that with the current setup the bubbles as small as 10 μm can be easily distinguished. The average size of the bubbles generated under the given conditions in two-phase system is 410 μm at frother concentration of 0.004%, which is in good correspondence with the results of other works. The effect of frother on bubble size was probed. Increasing frother concentration from 0 to 0.004% causes a reduction of bubble size from 700 to 400 μm. The bubble loading efficiency was reported. The result indicates that the fine particle is more easily entrapped than the coarse particle. Some factors, which have effect on measurement accuracy were discussed. The aeration speed has a significant effect on the accuracy of results, if it surpasses 30 mL/s, and the image becomes unclear due to the entrapment of fine particle. Another factor, which can affect observing results, is the sampling position. At a wrong sampling position, the images become unclear.
基金Project supported by the National Natural Science Foundation of China (Nos. 51176162 and 51276164)the National Basic Research Program (973) of China (No. 2009CB219802)+2 种基金the Zhejiang Provincial Science and Technology Project (No. 2012C21077)the Zhejiang Provincial Natural Science Foundation of China (No. Y1110642)the Program of Introducing Talents of Discipline to University (No. B08026),China
文摘A trajectory imaging based method for measuring the velocity and diameter of coal particles was presented.By using an industrial charge-coupled device(CCD)camera and a low power semiconductor laser,the images of coal particles under relatively long exposure time were recorded and then processed to yield both the velocities and sizes.Fundamental research on this method with special attention to recording parameters,e.g.,magnification factor and exposure time,was carried out.For most of the test cases,the results agree with those obtained by particle image velocimetry(PIV)and shadow imaging method.Measurements with good accuracy can be obtained when the imaging magnification factor and exposure time are set appropriately,making N be larger than 3.5,and R between 5-7,where N and R are the number of pixels occupied by the average width and the ratio of length to width of particle trajectory on the image,respectively.The work indicates the feasibility and potential application of the present measurement method for online measurement of coal powder in pipes in industrial power plants.
文摘The use of functional size measurement(FSM) methods in software development organizations is growing during the years. Also, object oriented(OO) techniques have become quite a standard to design the software and, in particular, Use Cases is one of the most used techniques to specify functional requirements. Main FSM methods do not include specific rules to measure the software functionality from its Use Cases analysis. To deal with this issue some other methods like Kramer's functional measurement method have been developed. Therefore, one of the main issues for those organizations willing to use OO functional measurement method in order to facilitate the use cases count procedure is how to convert their portfolio functional size from the previously adopted FSM method towards the new method. The objective of this research is to find a statistical relationship for converting the software functional size units measured by the International Function Point Users Group(IFPUG) function point analysis(FPA) method into Kramer-Smith's use cases points(UCP) method and vice versa. Methodologies for a correct data gathering are proposed and results obtained are analyzed to draw the linear and non-linear equations for this correlation. Finally, a conversion factor and corresponding conversion intervals are given to establish the statistical relationship.
基金financially supported by the National Natural Science Foundation of China(Nos.51576016 and 51476012)
文摘In this study,the particle size-resolved distribution from a China-3 certificated light-duty diesel vehicle was measured by using a portable emission measurement system（PEMS）.In order to examine the influences of vehicle specific power（VSP） and high-altitude operation,measurements were conducted at 8 constant speeds,which ranged from 10 to 80 km/hr at10 km/hr intervals,and two different high altitudes,namely 2200 and 3200 m.The results demonstrated that the numbers of particles in all size ranges decreased significantly as VSP increased when the test vehicle was running at lower speeds（〈 20 km/hr）,while at a moderate speed（between 30 and 60 km/hr）,the particle number was statistically insensitive to increase VSP.Under high-speed cruising conditions,the numbers of ultrafine particles and PM2.5were insensitive to changes in VSP,but the numbers of nanoparticles and PM10 surged considerably.An increase in the operational altitude of the test vehicle resulted in increased particle number emissions at low and high driving speeds;however,particle numbers obtained at moderate speeds decreased as altitude rose.When the test vehicle was running at moderate speeds,particle numbers measured at the two altitudes were very close,except for comparatively higher number concentrations of nanoparticles measured at 2200 m.
基金support of National Natural Science Foundation of China (No.50905010)Fund of National Engineering and Research Center for Commercial Aircraft Manufacturing (No.SAMC12-JS-15-044)
文摘Operations in assembling and joining large size aircraft components are changed to novel digital and flexible ways by digital measurement assisted alignment.Positions and orientations（P＆O）of aligned components are critical characters which assure geometrical positions and relationships of those components.Therefore,evaluating the P＆O of a component is considered necessary and critical for ensuring accuracy in aircraft assembly.Uncertainty of position and orientation（U-P＆O）,as a part of the evaluating result of P＆O,needs to be given for ensuring the integrity and credibility of the result;furthermore,U-P＆O is necessary for error tracing and quality evaluating of measurement assisted aircraft assembly.However,current research mainly focuses on the process integration of measurement with assembly,and usually ignores the uncertainty of measured result and its influence on quality evaluation.This paper focuses on the expression,analysis,and application of U-P＆O in measurement assisted alignment.The geometrical and algebraical connotations of U-P＆O are presented.Then,an analytical algorithm for evaluating the multi-dimensional U-P＆O is given,and the effect factors and characteristics of U-P＆O are discussed.Finally,U-P＆O is used to evaluate alignment in aircraft assembly for quality evaluating and improving.Cases are introduced with the methodology.
基金the State Key Development Program for Basic Research of China(2013CB632601)the National High Technology Research and Development Program of China(2011AA060704)+1 种基金the National Natural Science Foundation of China(21476236,91434126)the National Science Fund for Distinguished Young Scholars(21025627)
文摘The objective of this work is using the online measurement method to study the process of precipitation of nickel hydroxide in a single-feed semi-batch stirred reactor with an internal diameter ofD = 240mm. The effects of impeller speed, impeller type, impeller diameter and feed location on the mean particle size d43 and particle size distribution （PSD） were investigated, d43 and PSD were measured online using a Malvern Insitec Liquid Pro- cess Sizer every 20 s. It was found that d43 varied between 13 kwh and 26 lain under different operating conditions, and it decreased with increasing impeller diameter. When feeding at the off-bottom distance of D/2 under lower impeller speeds, d43 was significantly smaller than that at D/3. PSDs were slightly influenced by operating conditions.
基金supported by the National Basic Research Program (973) of China (No. 2008CB418006)the National Special Program of Water Environment (No.2009ZX07106-001-002)+1 种基金the National Natural Science Foundation of China (No. 31070355)the National Major Science and Technology Program for Water Pollution Control and Treatment (No. 2009ZX07101-013)
文摘A quantitative protocol for the rapid analysis of Microcystis cells and colonies in lake sediment was developed using a modified flow cytometer, the CytoSense. For cell enumeration, diluted sediment samples containing Microcystis were processed with sonication to disintegrate colonies into single cells. An optimized procedure suggested that 5 mg dw （dry weight）/mL dilution combined with 200 W x 2 min sonication yielded the highest counting efficiency. Under the optimized determination conditions, the quantification limit of this protocol was 3.3x104 cells/g dw. For colony analysis, Microcystis were isolated from the sediment by filtration. Colony lengths measured by flow cytometry were similar to those measured by microscopy for the size range of one single cell to almost 400 ~tm in length. Moreover, the relationship between colony size and cell number was determined for three Microcystis species, including Microcystisflos-aquae, M. aeruginosa and M. wessenbergii. Regression formulas were used to calculate the cell numbers in different- sized colonies. The developed protocol was applied to field sediment samples from Lake Taihu. The results indicated the potential and applicability of flow cytometry as a tool for the rapid analysis of benthic Microcystis. This study provided a new capability for the high frequency monitoring of benthic overwintering and population dynamics of this bloom-forming cyanobacterium.
基金Project(51804346)supported by the National Natural Science Foundation of ChinaProject(2019JJ50767)supported by the Natural Science Foundation of Hunan Province,ChinaProject(KY[2017]125)supported by Youth Foundation of Guizhou Education Department,China。
文摘The growing characteristics of metallic iron particles during reductive roasting of boron-bearing magnetite concentrate under different conditions were investigated.The size of the metallic iron particles was quantitatively measured via optical image analysis with consideration of size calibration and weighted ratio of image numbers in the core,middle and periphery zones of cross-section of pellets.In order to guarantee the measurement accuracy,54 images were captured in total for each specimen,with a weighted ratio of 1:7:19 with respect to the core,middle and periphery section of the cross-section of pellets.Increasing reduction temperature and time is favorable to the growth of metallic iron particles.Based on the modification of particle size measurement,in terms of time(t)and temperature(T)a predicting model of metallic iron particle size(D),was established as:D=125−0.112t−0.2352T−5.355×10^−4t^2+2.032×10^−4t∙T+1.134×10^−4T^2.
文摘In the software engineering literature, it is commonly believed that economies of scale do not occur in case of software Development and Enhancement Projects （D＆EP）. Their per-unit cost does not decrease but increase with the growth of such projects product size. Thus this is diseconomies of scale that occur in them. The significance of this phenomenon results from the fact that it is commonly considered to be one of the fundamental objective causes of their low effectiveness. This is of particular significance with regard to Business Software Systems （BSS） D＆EP characterized by exceptionally low effectiveness comparing to other software D＆EP. Thus the paper aims at answering the following two questions： （1） Do economies of scale really not occur in BSS D＆EP？ （2） If economies of scale may occur in BSS D＆EP, what factors are then promoting them？ These issues classify into economics problems of software engineering research and practice.
文摘[ Objective ] The paper was to study growth and physical structure of Holstein cows at specific phase under intensive rearing conditions in the South China. [ Method] The body sizes of 279 Holstein cows including 49 calves, 35 young cows and 195 adult cows in the experimental farm of Yangzhou University were measured. The raw data were processed by computer to obtain body size index at various physiological stages. The body size indexes were analyzed by SPSS 15.0 software to reflect changes in different physiological stages and various parities of cows. Body size indexes such as body height, body length and heart girth of young cows and calves were fitted by scatter plot. [ Result] The eider the cows were, the longer their bodies were. Calves had a stable growth and development. The body size of young cow at different month-ages was imbalanced. The physical structure of adult cows showed no regularity at different parities, so the specific feeding for growth and development of bone should be strengthened in multiparous cows. [ Conclusion] The study provides reference for keeping management of calves, breeding and keeping management of young cows as well as selection and assortative mating of adult cows.
文摘In this work,four samples of TiO_(2) powder materials with different structures(rutile,anatase),surface coatings and morphologies(rod,pseudo-spherical)were characterized by four partners involving complementary methods.With the aim of producing inter-laboratory reproducibility data,the specific surface-area,bulk density,and number size distribution were measured,yielding a satisfying agreement between partners.The equivalent diameter of constituent particles was determined from the sample volume specific surface area(VSSA)–accounting for polydispersion–and compared to electron microscopy(EM).Constituent particle diameters ranged from 15 to 225 nm according to EM analyses.The relative discrepancies between VSSA-based and EM-based diameters were found within±20%.Out of the four samples under study,TiO_(2)μ-rutile leads to a larger deviation,which was attributed to surface coating thanks to complementary analysis.Assuming that the sample is pure,an equivalent diameter based on the VSSA can be determined,provided that the shape of constituent particles is known or supposed.
文摘We present the spot size dependence of dielectric multilayer filters for use in dense WDM systems. We found large dependences of filter performances on the spot size and the incident angle of input light, which should be important for miniaturizing multi-channel add/drop filters.
基金supported by the Science and Technology Development Planning Program of the Guangzhou City Bureau of Scienceand Technology,China(grant200773-D2091)
文摘A modified regularization algorithm with a more proper operator was proposed for the inversion of particle size distribution （PSD） from light-scattering data in a laser particle sizer based on the Mie scattering principle. The Generalized Cross-Validation （GCV） method and the L-curve method were used for deter- mining the regularization parameter. The Successive Over-Relaxation （SOR） iterative method was used to increase the exactness and stability of the converged result. The simulated results based on the modified algorithm are in a good agreement with the experimental data measured for nine standard particulate samples, their mixtures as well as three natural particulate materials with irregular shapes, indicating that this modified regularization method is not only feasible but also effective for the simulation of PSD from corresponding light-scattering data.
基金The authors would like to acknowledge the following funding support:National Institutes of Health[NIH-R21 AR076708]National Science Foundation[NSF-BSF 1822196,DGE-1610403].
文摘The scaffold pore size influences many critical physical aspects of tissue engineering,including tissue infiltration,biodegradation rate,and mechanical properties.Manual measurements of pore sizes from scanning electron micrographs using ImageJ/FIJI are commonly used to characterize scaffolds,but these methods are both time-consuming and subject to user bias.Current semi-automated analysis tools are limited by a lack of accessibility or limited sample size in their verification process.The work here describes the development of a new MATLAB algorithm,PoreScript,to address these limitations.The algorithm was verified using three common scaffold fabrication methods(e.g.,salt leaching,gas foaming,emulsion templating)with varying pore sizes and shapes to demonstrate the versatility of this new tool.Our results demonstrate that the pore size characterization using PoreScript is comparable to manual pore size measurements.The PoreScript algorithm was further evaluated to determine the effect of user-input and image parameters(relative image magnification,pixel intensity threshold,and pore structure).Overall,this work validates the accuracy of the PoreScript algorithm across several fabrication methods and provides user-guidance for semi-automated image analysis and increased throughput of scaffold characterization.
基金financial support of the Central Guide Local Science and Technology Development Project of Hubei Province of China(No.2023EGA008)the Wuhan Natural Science Foundation Exploration Project(Chenguang Project)(No.2024040801020309).
文摘As the main use of TBM(tunnel boring machine)cutter ring(DC53 steel)currently is difficult to meet the requirements of high wear resistance and high toughness synchronously in its service environment,a new HWR0 steel with 4%Cr-3%V for TBM cutter ring has been developed to control carbides in steel.Precipitation behavior of carbides in HWR0 steel was investigated through theoretical calculation by Thermo-Calc and experimental measurement using scanning electron microscope,energy dispersive spectrometer,electron probe X-ray micro-analyzer,and laser particle size analyzer.The results show that three different carbides are precipitated during cooling.And the as-cast electroslag remelting ingot of HWR0 steel primarily consists of many blocky or strip-like MC distributed along grain boundaries,few chrysanthemum-like M_(6)C concentrated at grain boundary intersections,and a large quantity of fine M_(23)C_(6)and M_(6)C dispersed in the matrix.Compared with DC53 steel,HWR0 steel has more high-hardness carbides MC,which are discontinuously distributed at the grain boundaries,achieving the dual improvement of wear resistance and impact toughness.Cooling rates significantly influence the carbides distribution and grain size.A slower cooling rate exacerbates the segregation of alloying elements,which leads to the localized enrichment of Mo and the subsequent precipitation of M_(6)C carbides at grain boundary intersections.In contrast,faster cooling rate decreases the element segregation,promotes carbide nucleation and limits the space for carbides growth,which results in finer size and distribution of carbides and grains.Higher cooling rates yield a more homogeneous microstructure with uniform MC compositions and promote the preferential formation of M_(6)C carbides along grain boundaries,which enhances the mechanical properties.
基金sponsored by the California Air Resources Board (ARB) under DRI project number 04-307U.S. EPA's Supersites Program at Fresno
文摘Size distributions of ambient aerosols at the Fresno Supersite were measured with four commercially available scanning mobility particle sizers （SMPS）. TSI nano, TSI standard, Grimm, and MSP instruments were collocated at the Fresno Supersite and particle size distributions were measured continuously from August 18 through September 18, 2005. For particles with diameters between 10 and 200 nm, differences among hourly-average ambient particle concentrations ranged from 0% between the TSI nano and Grimm in the 30-50 nm size range to 39% between the Grimm and MSP in the 10-30 nm size range. MSP concentrations were 10-33% lower than those measured with the TSI standard for particles smaller than 200 nm. The TSI nano and TSI standard agreed to within 5% in their overlapping size range （10-84 nm）. The TSI nano and Grimm agreed to within 40% for 5-10 nm particles.
文摘How do you measure the size of a one-dimensional figure?The size of a line segment is given by its length.How do you measure the size of two-dimensional figures?Rectangles and other polygons are two-dimensional.There are two common ways of measuring these figures.Perimeter measures the boundary.Area measures the space inside the figure.
文摘There are three different common w(?)measure the size of a three dimensional figure. Consider the shoe box below. We can measure the total length of its edges. Like perimeter, this is one-dimensional. We can measure its surface area,which is two-dimensional. Or we can measure its volume,which is three-dimensional. The shoebox has edges of lengths 14inches,5inches,and 7inches, There are four edges of each length. (some are hidden from view.)The total length of all edges is 4·15"+4·7"+4·14",or 104inches.
基金supported by the National Key R&D Program(2023YFD1300202)National Natural Science Foundation of China(Grant No.32172780)Key Laboratory of Smart Agricultural Technology in Tropical South China,National Engineering Research Center for Breeding Swine Industry,and Guangdong Engineering Technology Research Center for Agricultural Farming Internet of Things.
文摘Pig body measurement is an important evaluation criterion for breeding and production management.Automatic measurement algorithms for pig body sizes exhibit sensitivity to the point cloud posture,but non-standard pig postures may result in inaccurate joint point localization in body measurement,further affecting measurement accuracy and the commercial application of these algorithms.To address this challenge,this paper proposed a pig point cloud posture transformation method based on pig’s skeleton model to adjust non-standard postures before conducting body size measurements.The method utilized an improved L1-median skeleton model to extract the three-dimensional skeleton of the pig point cloud,capturing the skeleton joint points on the target pig’s head,body,and limbs.By binding the skeleton joint points with the local point cloud and using rotation matrices,non-standard postures were adjusted to standard ones,enabling accurate body size measurements.The experimental results demonstrated that the average relative errors between the transferred posture and the original standard posture were reduced to 0.89%in body length,0.76%in body width(front),1%in body width(back),0.89%in body height(front),1.7%in body height(back),2.03%in thoracic circumference,3.37%in abdominal circumference,and 1.89%in rump circumference.To conclude,the posture standardization transfer method can significantly reduce errors in important body size parameters such as body length,body height,and body width.The method displays a greater stability and robustness compared to existing posture normalization and regression adjustment methods,providing both guidance and insight for future research in intelligent agriculture.
文摘A pinhole camera for imaging X-ray synchrotron radiation from a dipole magnet is now in operation at the Shanghai Synchrotron Radiation Facility （SSRF） storage ring.The electron beam size is derived by unfolding the radiation image and the point spread function （PSF） with deconvolution techniques.The performance of the pinhole is determined by the accuracy of the PSF measurement.This article will focus on a beam-based calibration scheme to measure the PSF system by varying the beam images with different quadrupole settings and fitting them with the corresponding theoretical beam sizes.Applying this method at SSRF,the PSF value of the pinhole is revised from 37 to 44μm.The deviation in beam size between the theoretical value and the measured value isminimized to 4% after calibration.This optimization allows us to observe the horizontal disturbance due to injection down to as small as 0.5μm.
