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1
Denkena, Berend, Thilo Grove und Eike Hasselberg. „Workpiece Shape Deviations in Face Milling of Hybrid Structures“. Materials Science Forum 825-826 (Juli 2015): 336–43. http://dx.doi.org/10.4028/www.scientific.net/msf.825-826.336.
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A currently common method to design high-performance workpieces is to combine two or more materials to one compound. This way, workpieces can be composed of the most qualified materials according to local loads.When machining high-performance workpiece compounds (e.g. cylinder crankcases), high quality requirements concerning the accuracy of dimension and shape as well as the surface roughness must be fulfilled. However, machining of workpiece compounds leads to unfavorable changes of the workpiece quality in comparison to machining of the single materials. Significant shape deviations occur when different materials are machined alternately in one cutting operation. This is due to unequal material properties, cutting characteristics, chip formation mechanisms as well as characteristic interactions between the single components.The focus of this research is on the process understanding as well as on the identification of measurable shape deviation indicators that describe the surface finish of hybrid structures. Here, the indicators material height deviation, transition deviation at the material joint, surface roughness deviation as well as surface defects (e.g. scratches) on the surface are presented. The overall aim of this research is to predict the surface finish resulting from face milling an aluminum/cast iron compound or a polyurethane/cast iron compound.
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Novak, S., V. Drizhd und O. Dobrostan. „COMPARATIVE ANALYSIS OF DATA ON THE DURATION OF FIRE EXPOSURE BEFORE REACHING THE CRITICAL TEMPERATURE STEEL OBTAINED FOR SAMPLES STANDARDIZED AND SAMPLE SIZE REDUCTION FROM FIREPROOF MATERIALS "ENDOTERM 400202" AND "ENDOTERM 210104"“. Науковий вісник: Цивільний захист та пожежна безпека 1, Nr. 2 (30.12.2018): 18–27. http://dx.doi.org/10.33269/nvcz.2018.2.18-27.
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The results of the determination of the convergence of experimental data on the duration of fire exposure under the standard temperature regime until the critical temperature of steel obtained for standardized samples (columns) and samples of reduced sizes (plates) with the use of the reactive fireproof material "Endoterm 400202", flowing under the thermal influence in fire conditions, and passive fireproof material (plates) «Endoterm 210104». It has been established that the deviation of the values of the duration of fire exposure to achievement the critical temperature of steel, determined for samples of reduced sizes, from the experimental data obtained on standardized samples, is, on average,–9,5% and 4,7% for reactive and passive fireproof materials, respectively. In this case, for a reactive fireproof material the value of this deviation is in the range from -24,0 % to 17,6 %, and most of it (93 %) has negative values (the duration of fire exposure until the critical temperature of steel, determined for most samples reduced sizes does not exceed the experimental data obtained for standardized samples). For a passive fireproof material, the values of deviation are in the range from -24,7 % to 23,1 %, and most of them (75 %) have positive values (the duration of fire exposure until the critical temperature of steel, determined for most samples of reduced sizes, exceeds the experimental data obtained for standardized samples). The average deviation is 12,1 % and 10,8 %, respectively, for reactive and passive fireproof materials. A regularity is established regarding the dependence of the deviation value of the critical temperature of steel. For a reactive fireproof material, with a increase of the critical temperature from 350 °C to 450 °C (and in some samples – up to 500 °C or more) the deviation decreases. With a further increase of this temperature, the deviation increases (up to temperature of 650 °C), and then decreases. For a passive fireproof material with an increase of the critical temperature from 350 °C to 500 °C (and in some samples – up to 550 °C or more) the deviation increases. With a further increase of this temperature the value of the deviation decreases.
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Teaca, Robert Stefanut, und Gheorghe Brabie. „Analysis of Geometry Deviations in Case of Conical Mini-Parts Obtained by Forming Process from Copper-Zinc Alloy (CuZn37) Sheets“. Applied Mechanics and Materials 657 (Oktober 2014): 158–62. http://dx.doi.org/10.4028/www.scientific.net/amm.657.158.
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Mini forming is an appropriate technology to manufacture small metal parts, as these are required in many industrial products resulting from mini-technology. This paper work want to underline the fact that even in down scale there are problems regarding deviation from the required dimensions. One of the problems is scaling effects, which occur in tribological aspects such as the friction coefficient, which increases with decreasing specimen size. Simulations investigations into mini forming process were carried out and mini conical parts have been obtained with different geometries. . The main objective is to observe and quantify behaviour of the mini parts during forming process and geometry deviations that affect the final product. The material used in this analysis is copper - zinc alloy with anisotropic properties. During forming process of conical mini-parts, the material record important variation along the part length and generate important shape deviation. This phenomenon causes deviations of sidewall angle, superior diameter, inferior diameter, mini part height, and connection radius between the part bottom and sidewall. There are multiple factors that affect the geometry deviations: sidewall angle, friction coefficient, tools gap, punch radius, and punch speed. The Dynaform 5.9.1 software was used to simulate the forming process. The part obtained after each simulation was analyzed and measured to quantify the deviation from the desired geometry on the final conical mini-part. In the final part of this paper some conclusions regarding geometry deviation of conical mini-parts obtained by forming are presented.
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Wang, Shu Lung, und Ting Yu Chueh. „Analysis of the Material Removal Rate of Micro-Hole Machining of Ceramic Materials“. Advanced Materials Research 347-353 (Oktober 2011): 1572–75. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.1572.
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This study discussed what rotary ultrasonic machining (RUM) and tool geometry parameters combination can obtain bigger material removal rate (MRR) in drilling. The experimental configuration of this study was planned using Taguchi orthogonal array, where the drill diameter, rotation speed, power and feed rate were taken as the experimental factors. A relation model among the MRR and standard deviation of the holes walls and processing parameters and tool geometry was established, so as to achieve maximum MRR of the overall deep holes walls. The experimental results proved that application of the optimized parameters combination in rotary ultrasonic machining of holes processing can obtain bigger and better removal rate of holes walls. The effect of control factors on the holes quality was discussed from the straightness deviation and maximum material removal rate of related factors on the holes when the Taguchi method was used in rotary ultrasonic machining of holes drilling. The results showed that rotation speed, power, and feed rate under bigger level have a larger MRR than that of other level in a fixed drill diameter.
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Wolf, Mario, Alexey Rybakov, Richard Hinterding und Armin Feldhoff. „Geometry Optimization of Thermoelectric Modules: Deviation of Optimum Power Output and Conversion Efficiency“. Entropy 22, Nr. 11 (29.10.2020): 1233. http://dx.doi.org/10.3390/e22111233.
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Besides the material research in the field of thermoelectrics, the way from a material to a functional thermoelectric (TE) module comes alongside additional challenges. Thus, comprehension and optimization of the properties and the design of a TE module are important tasks. In this work, different geometry optimization strategies to reach maximum power output or maximum conversion efficiency are applied and the resulting performances of various modules and respective materials are analyzed. A Bi2Te3-based module, a half-Heusler-based module, and an oxide-based module are characterized via FEM simulations. By this, a deviation of optimum power output and optimum conversion efficiency in dependence of the diversity of thermoelectric materials is found. Additionally, for all modules, the respective fluxes of entropy and charge as well as the corresponding fluxes of thermal and electrical energy within the thermolegs are shown. The full understanding and enhancement of the performance of a TE module may be further improved.
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Oreshkin, Oleg, Daniil Panov, Laura Kreinest, André Temmler und Alexander Platonov. „Shape Deviation of Surface Structures Produced by WaveShape (Structuring by Laser Remelting) on Ti6Al4V and a Method for Deviation Reduction“. Micromachines 12, Nr. 4 (29.03.2021): 367. http://dx.doi.org/10.3390/mi12040367.
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Laser structuring by remelting (WaveShape) is a manufacturing process for metal surfaces in which structures are generated without material removal. The structuring principle is based on the controlled motion of the three-phase line in the area of the solidification front. The contour of the solidification front is imprinted into the remelting track during the continuous solidification process. Typically, harmonic surface structures in the form of sinusoidal oscillations are generated by means of WaveShape with virtually no material loss. However, a significant shape deviation is often observed over a wide range of process parameters. In this study, it was found that much of the shape deviation is concentrated at a spatial wavelength equal to half the spatial wavelength used for structuring. Therefore, an approach to reduce the shape deviations was specifically investigated by superimposing a compensation signal on the harmonic structuring signal. In this approach, a compensation signal with half the spatial wavelength was varied in phase and amplitude and superimposed on the structuring signal. Amplitude and phase shift of the compensation signal were further investigated for selected laser beam diameters and spatial wavelengths. This demonstrated that a shape deviation of harmonic surface structures on titanium alloy Ti6Al4V could be reduced by up to 91% by means of an adapted compensation signal.
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ROY, MICHAËL, SEBTI FOUFOU und FRÉDÉRIC TRUCHETET. „MESH COMPARISON USING ATTRIBUTE DEVIATION METRIC“. International Journal of Image and Graphics 04, Nr. 01 (Januar 2004): 127–40. http://dx.doi.org/10.1142/s0219467804001324.
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We propose a mesh comparison method using a new attribute deviation metric. The considered meshes contain geometrical and appearance attributes (material color, texture, temperature, etc.). The proposed deviation metric computes local differences between the attributes of two meshes. A mesh comparison assessment can be done easily and quickly using this metric. The techniques proposed are applicable in a number of ways, e.g. 3D matching and registration, and the example described in the paper is the simplification of a surface by iteratively reducing its complexity according to an error metric. The results are presented showing the success of the algorithm through comparisons with other measures and with three different simplification algorithms.
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CORRALES MAGALLANES, ADI, LUIS DEL LLANO VIZCAYA, CELSO EDUARDO CRUZ GONZALEZ, VICENTE BRINGAS RICO, ALDO AUGUSTO LOPEZ MARTINEZ und EUSEBIO JIMENEZ LOPEZ. „NUMERICAL-EXPERIMENTAL EVALUATION OF A HYPERELASTIC POLYURETHANE ADHESIVE“. DYNA 96, Nr. 3 (01.05.2021): 246–49. http://dx.doi.org/10.6036/9783.
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This article presents the results of the experimental tests carried out on a polyurethane hyperelastic adhesive. The Mooney-Rivlin, Ogden and Yeoh models were analyzed between others, with different order and parameters using the finite element method and the Ansys V17.1 package, with the aim of evaluating the convergence of a general hyperelastic model, to subsequently manufacture specimens and perform experimental uniaxial stress tests. The information obtained from the tests was supplied to a curve fitting model for several hyperelastic models, seeking to obtain a correlation between these tests. New analyzes were performed with the finite element method with the materials considered and the curves adjusted. The results were studied and the numerical hyperelastic model closest to reality was selected, observing that the 1st order Yeoh model presented significant deviations between -30% to 60% in the experimental stiffness, the 3rd order Yeoh model presented deviations of -5% to -30%, while Ogden models of 1st and 3rd order presented deviations of -3.5% to 25% and -3% to 20%, before approaching the critical load, where the model of Ogden of 1st order presented a deviation of 0.66% and that of 3rd order of -3.59%. The 2 parameter Mooney-Rivlin model presents a deviation of 3.9% when it approaches the critical load, but values from -2.04% to 15% during the development of the stress test, so that model proved to be the most appropriate to analyze the material investigated in this work. Key Words: Hyperelastic material, Experimental Methods, Numerical Methods, FEA
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Shu, Qijiang, Jing Liu, Xu Lan, Jia Long, Jie Yang, Chong Wang und Yu Yang. „Correction analysis for the deviation between vacuum furnace and material growth temperatures“. Vacuum 144 (Oktober 2017): 21–26. http://dx.doi.org/10.1016/j.vacuum.2017.07.006.
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Qiu, Xiao Lin, Guo Wei Chang, Shu Ying Chen und Jian Guo He. „Measurement System of Contact Angle between Molten Steel Droplet and Refractory Material“. Advanced Materials Research 299-300 (Juli 2011): 277–81. http://dx.doi.org/10.4028/www.scientific.net/amr.299-300.277.
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The distinct images of molten steel droplets were obtained utilizing a home-made experimental equipment, and the method which measures the contact angle between the molten steel droplet and the refractory material using a computer image processing technology and Visual C++ language was represented, meanwhile the measurement system of the contact angle was developed. The results show that the maximum deviation of the measurement system is 0.13° comparing with the actual measurement results, the minimum deviation is 0.03°, and the mean deviation is 0.06°. Under this experiment conditions, the contact angle increases 1.2° when the quality of sample increases from 0.2g to 0.8g at 1550°C, and the contact angle increases 2.3° when the temperature increases from 1550°C to 1600°C for the sample of 0.2g.
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Zhang, Mu-Hang, Xiao-Hong Shen, Lei He und Ke-Shi Zhang. „Investigation of Deformation Inhomogeneity and Low-Cycle Fatigue of a Polycrystalline Material“. Applied Sciences 11, Nr. 6 (17.03.2021): 2673. http://dx.doi.org/10.3390/app11062673.
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Considering the relationship between inhomogeneous plastic deformation and fatigue damage, deformation inhomogeneity evolution and fatigue failure of superalloy GH4169 under temperature 500 °C and macro tension compression cyclic loading are studied, by using crystal plasticity calculation associated with polycrystalline representative Voronoi volume element (RVE). Different statistical standard deviation and differential entropy of meso strain are used to measure the inhomogeneity of deformation, and the relationship between the inhomogeneity and strain cycle is explored by cyclic numerical simulation. It is found from the research that the standard deviations of each component of the strain tensor at the cyclic peak increase monotonically with the cyclic loading, and they are similar to each other. The differential entropy of each component of the strain tensor also increases with the number of cycles, and the law is similar. On this basis, the critical values determined by statistical standard deviations of the strain components and the equivalent strain, and that by differential entropy of strain components, are, respectively, used as fatigue criteria, then predict the fatigue–life curves of the material. The predictions are verified with reference to the measured results, and their deviations are proved to be in a reasonable range.
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Wang, Xue Jun, Yan Fang Ding, Hong Bin Liu, Yi Lin Chi und Ping Xu. „Study on Running Deviation and Adjusting Deviation of Belt Conveyor's Structure Based on Synchronous Technology“. Advanced Materials Research 634-638 (Januar 2013): 3794–97. http://dx.doi.org/10.4028/www.scientific.net/amr.634-638.3794.
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Belt conveyor is widely used in a variety of automated production lines and bulk material transportation is one of the most important applications. In order to improve the accuracy of the belt conveyors, it is need not only to strictly control the production crafts, more importantly, to improve the rationality of the structure and design level. Running deviation and adjusting deviation problem are important issues to be considered in a belt conveyor design process. In this study, the 3D synchronous technology of Solid Edge ST4 will be applied in the design of the belt conveyor to design a new type of anti-deviation structure. In the design process, we combine the synchronous technology with modular technology and top-down assembly modeling techniques to confirm the subject and adjust deviation. The key is the application of synchronous technology in 3D design and the new structure in Running Deviation and Adjusting Deviation. It turned out that the application of above technology can reduce design errors and avoids the repeated design, thus greatly improving the efficiency of the engineer's design. Meanwhile, the study of running deviation can make the structure of adjusting deviation come true.
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ZHU, Hong, und Gaoyan HOU. „Optimization of SLS forming parameters in the dimensional accuracy of formed parts“. E3S Web of Conferences 233 (2021): 01069. http://dx.doi.org/10.1051/e3sconf/202123301069.
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In selective laser sintering powder forming, the performance and dimensional accuracy of the formed part are affected by the process parameters. Different materials have different process parameters, and there is still no reference standard for PA materials. To solve this problem, in response to this problem, PA2200 material was selected, and the influence of scanning interval and scanning speed on the dimensional accuracy of the formed part was analyzed. Through theoretical analysis and experiments, the optimal process parameters were obtained. The best combination of parameters is a scanning speed of 4000mm/s, a scanning interval of 0.5mm, and the size of the molded part has a X-axis deviation -0.35%, a Y-axis deviation -0.4%, and a Z-axis deviation -0.25%.
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Durgun, Ismail. „Sheet metal forming using FDM rapid prototype tool“. Rapid Prototyping Journal 21, Nr. 4 (15.06.2015): 412–22. http://dx.doi.org/10.1108/rpj-01-2014-0003.
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Purpose – The purpose of this paper is to investigate usage of fused deposition modeling (FDM)-based sheet metal tooling for small lot productions as a real case. FDM-based sheet metal tooling was used for stamping prototype parts for two different materials to evaluate dimensional conformance. Design/methodology/approach – The experimental process of data capture used the following steps: sheet metal parts were stamped and optically scanned at every 10th interval for both DC04 and S355MC material. FDM-based upper and lower dies were optically scanned at 1st, 51st and 101st intervals. Dimensional conformance analyses were carried out by using scanned data to evaluate the behavior of FDM dies against DC04 and S355MC materials in terms of geometric deviation. Findings – Satisfactory results were obtained for DC04 material by using FDM-based tooling, and overall deviation was at an acceptable level in terms of production tolerance. S355MC material is harder than DC04 and results were not convenient in terms of tolerance range. Geometric deviation of FDM dies was slightly increased and after the 50th part, increased drastically due to squeezing of FDM layers. Experiments showed that this method can be used for DC04 material and up to 100 parts can be stamped within the tolerance range. Using FDM-based sheet metal tooling, product development phase can be shortened in terms of leading time. Originality/value – This paper presents a study to create an alternative tooling method to shorten product cycle and product development phase by integrating rapid tooling methods to low-volume production.
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Timoshkov, P. N., V. A. Goncharov, M. N. Usacheva und A. V. Khrulkov. „INFLUENCE OF TECHNOLOGICAL PARAMETERS ON CHARACTERISTICS OF POLYMER COMPOSITE MATERIALS IN AUTOMATED LAYUP OF PREPREGS (review)“. Proceedings of VIAM, Nr. 6 (2021): 46–55. http://dx.doi.org/10.18577/2307-6046-2021-0-6-46-55.
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The main technological factors when using ATL and AFP technologies are material temperature, laying speed, rolling pressure and no deviation from the required laying trajectory. The article discusses the influence of technological factors on some characteristics of polymer composite materials. The optimum laying temperature should provide the required adhesion. The rate of laying should provide heating of the material without its technological properties. The rolling pressure during laying should ensure optimal porosity and thickness of the material.
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Liu, Jun Xu. „Research and Design on a New Roll of Material Conveying Composite Regulating Machine System“. Advanced Materials Research 503-504 (April 2012): 432–36. http://dx.doi.org/10.4028/www.scientific.net/amr.503-504.432.
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This paper studies the old offset machine mathematical model, corrects the shortcomings of its mathematical model and presents a more effective, more reasonable mathematical models. Then the conceptual designs, system design, structure design of the model are carried out. After nearly 2 years operating, the deviation adjusting mechanism has been proved to possess a good practicability and adjusting deviation.
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Mazurina, О. V., und О. I. Kashura. „New opportunities for surgical treatment of paralytic strabismus in children“. Modern technologies in ophtalmology, Nr. 1 (29.05.2021): 145–47. http://dx.doi.org/10.25276/2312-4911-2021-1-145-147.
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Purpose. To assess the clinical effectiveness of the developed surgical method for treating paralytic strabismus. Material and methods. The operation was performed on 32 patients with paralytic strabismus (32 eyes) aged 3 to 12 years. All patients had diplopia in the primary gaze position or in a small abduction. Convergent strabismus was diagnosed in 26 children (81%), divergent strabismus – in 6 patients (19%), in 34% of cases (11 people) strabismus was with a vertical component. Strabismus angle according to Hirshberg before surgery: horizontal deviation from 10 to 30°, vertical – from 5 to 15°. Results. On the 7–10th day after the operation, orthotropy and the appearance of mobility of the eyeball towards the affected muscle were achieved in all operated patients. In the long term (6–12 months) after surgery, 23 children (72%) fully recovered the mobility of the eyeball in 8 directions and formed stable binocular vision, and orthotropy remained. In 9 patients (28%), there was a limitation of the mobility of the eyeball to 5–7°. Conclusion. The proposed method for the surgical treatment of paralytic strabismus makes it possible to achieve in one stage the correction of the deviation angle and the improvement of mobility with the elimination of diplopia, avoids the appearance of postoperative vertical deviation and eliminates large deviation angles. Using the proposed method, it is possible to simultaneously correct both horizontal and vertical deviations. Key words: paralytic strabismus, deviation angle, horizontal deviation, vertical deviation.
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Al-Ramahi, Nawres J., Roberts Joffe und Janis Varna. „Criteria for crack path deviation in adhesive layer of bi-material DCB specimen“. Composites Part A: Applied Science and Manufacturing 147 (August 2021): 106408. http://dx.doi.org/10.1016/j.compositesa.2021.106408.
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Egoryshev, S. V. „The influence of criminal deviation on the demographic processes in the Republic of Bashkortostan“. RUDN Journal of Sociology 20, Nr. 1 (15.12.2020): 89–101. http://dx.doi.org/10.22363/2313-2272-2020-20-1-89-101.
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The current demographic situation in most regions of Russia is characterized by a number of negative trends associated with population decline, aging, low birth rate, high mortality, redistribution of migration flows and outflow of population, mainly of its young and working-age part, to the most economically developed regions, cities and abroad. Numerous factors influence the state and trends of demographic processes; this influence is studied and taken into account when the strategies of the demographic and social-economic policies of the country as a whole and its regions are considered. The social-economic development and its specific components including demographic processes are also determined by social deviations of a delinquent and criminal nature. The destructive consequences of criminal deviation for demographic processes are not obvious or critical, but they are manifested both directly (human losses) and indirectly (material and financial costs, increased mortality from alcohol, drugs, suicides, social exclusion of people who are sick or isolated due to deviations). Criminal deviation as a type of destructive social deviations is manifested mainly in crime and in those deviations that are its cause and corpus delicti. Based on the analysis of statistical and sociological data on the Republic of Bashkortostan, the author considers negative consequences of criminal deviation for the demographic situation and insists on the need to find effective measures to reduce them to a socially acceptable level (a criterion of such measures effectiveness).
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Chen, Xin Wu, und Zhan Qing Ma. „Material Texture Retrieval Using Contourlet-2.3 and Three Statistical Features“. Advanced Materials Research 233-235 (Mai 2011): 2495–98. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.2495.
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To improve the retrieval rate of contourlet transform texture retrieval system, a contourlet-2.3 transform based retrieval system was proposed. Six different features, including mean, standard deviation, absolute mean energy, L2 energy, skewness and kurtosis contributions to retrieval rates were examined. Based on the single feature ability in retrieval system, a contourlet-2.3 retrieval system was proposed. The feature vectors were constructed by cascading the standard deviation, absolute mean energy and kurtosis of each sub-band contourlet coefficients and the similarity measure used here is Canberra distance. Experimental results on 109 brodatz texture images show that the new retrieval algorithm can lead to a higher retrieval rate than several contourlet transform retrieval systems including the original contourlet transform, non-subsampled contourlet transform under the same structure.
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Polini, Wilma, und Andrea Corrado. „A Unique Model to Estimate Geometric Deviations in Drilling and Milling Due to Two Uncertainty Sources“. Applied Sciences 11, Nr. 5 (24.02.2021): 1996. http://dx.doi.org/10.3390/app11051996.
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Industry 4.0 involves the use of information and communication technologies to transform industry by intelligent networking machines and processes. The availability of big data sets from manufacturing and inspection allow for developing new and more accurate simulation models. This involves the development of new machining simulation models to consider the geometrical deviations of the workpiece due to the machine tool, the part datum surfaces and the fixturing equipment. This work presents a model that kinematically correlates the locator uncertainty, the form deviation on the part datum surface in contact with the locators and the volumetric uncertainty of the machine tool, with the geometric deviations of a surface due to a drilling or milling process. An analytical model was developed in a Matlab® file to simulate the surface geometrical deviations from nominal during drilling or milling. It is new as regards the state of the art because it takes into account two sources of uncertainty. This numerical approach allows for avoiding experimental tests, with a resultant saving of time, energy and material. It was applied to drilling, face milling and contouring processes. It was proved that machine tool volumetric uncertainty influences the form deviation of the machined surface, while the locator configuration and the datum form deviation affect the orientation of the machined surface, as should be in reality. The proposed model allows us to take into account geometrical deviations of the part datum surfaces of 0.001 mm, location deviations in the locators of ± 0.03 mm and machine tool positional and rotational uncertainties of 0.01 mm and σd=0.01∗π180 mm, respectively.
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Masutto, Cristina, und Cesare Cornoldi. „Cognitive Profiles and Deviation Patterns of Dyslexic Children“. Perceptual and Motor Skills 75, Nr. 1 (August 1992): 15–18. http://dx.doi.org/10.2466/pms.1992.75.1.15.
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Cognitive profiles of 20 dyslexic children were examined using a battery of neuropsychological tests. Their ages ranged from 90 to 114 mo. (M = 106.6 mo.). Intelligence and reading comprehension were normal, but the subjects had specific problems in decoding written material. These subjects were matched with a control group of same age, sex, and sociocultural status. The dyslexic children presented specific patterns of response on WISC—R subtests and failed a battery of cognitive tests examining subcomponents of reading. For each child, a deviation score was computed which represented the imbalance among the different cognitive functions. Greater imbalance was observed among the dyslexic children in development of cognitive functions than among the normal children.
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Zhou, Ji Mei, Ze Zhang und Yan Li Xiang. „Research on Foreign Body Detection for Granular Material Based on Feature Weighted OCSVM of Color Recognition“. Advanced Materials Research 734-737 (August 2013): 2983–89. http://dx.doi.org/10.4028/www.scientific.net/amr.734-737.2983.
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In granular materials processing, how to efficiently recognize and remove foreign bodies is very important. Training data including H,I mean and I standard deviation of target material are distinguished to be foreign bodies or not by training model, which is established using FWOCSVM method, while taking into account the characteristics of foreign body detection. A way to introduce the weight value reflecting the importance degree of attribute with its mean square deviation is developed to solve the problem, that is, attribute weights are not considered in OCSVM. The results show that FWOCSVM has more excellent performance than that of threshold or OCSVM .And color features adopted in the paper have excellent identification performance in above foreign bodies detection.
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Edelmann, André, Lisa Riedel und Ralf Hellmann. „Realization of a Dental Framework by 3D Printing in Material Cobalt-Chromium with Superior Precision and Fitting Accuracy“. Materials 13, Nr. 23 (27.11.2020): 5390. http://dx.doi.org/10.3390/ma13235390.
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We report on the generation of a cobalt-chromium dental framework with superior precision and fitting accuracy using selective laser melting. The objective of this study is the reduction of surface roughness and the possibility to manufacture a dental framework with high precision for passive fit with attachments, in particular a round tack. After selective laser melting, the dental framework is thermally post processed at 750 °C, shot-blasted with glass and highly polished. Nominal to actual 3D form deviation is analyzed by stripe light projection, revealing deviations being less than 250 μm, i.e., warpage is as low as to permit dental application and accurate passive fit. In particular, the critical area of the dental framework, the fixture to the implant (overdenture) shows negligible deviations. This superior fitting accuracy is confirmed by joining the bar with a testing stylus.
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Коробова, Анастасия Владиславовна. „DEVIATION AS A MEANS OF FOREGROUNDING IN LITERARY TEXT“. Вестник Тверского государственного университета. Серия: Филология, Nr. 2(69) (01.06.2021): 225–30. http://dx.doi.org/10.26456/vtfilol/2021.2.225.
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В данной статье появление девиации в художественном тексте рассматривается с точки зрения выполнения ею функции выдвижения с учётом её стилистического потенциала как средства смыслообразования. Материалом для интерпретации послужил текст произведения Дж. Сэлинджера «A Perfect Day for Bananafish» и встретившиеся в нём случаи девиации. In this article, the occurrence of deviation in a literary text is considered from the point of view of performing its foregrounding function, as a means of better interpreting text. The material for the analysis is the text of the short story «A Perfect Day for Bananafish» by J. Salinger and the cases of deviation in it.
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Bougot-Robin, K., C. Pang, X. Pommarede, A. Itawi, A. Talneau, J. P. Hugonin und H. Benisty. „Embedded Effective-Index-Material in Oxide-Free Hybrid Silicon Photonics Characterized by Prism Deviation“. Journal of Lightwave Technology 32, Nr. 19 (01.10.2014): 3283–89. http://dx.doi.org/10.1109/jlt.2014.2341833.
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Xing, Yan Feng, Yan Song Wang und Xiao Yu Zhao. „Tolerance Analysis for Compliant Assemblies with Thickness Deviation“. Advanced Materials Research 139-141 (Oktober 2010): 1494–97. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.1494.
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Dimensional tolerance is an important factor for the geometry quality of products. The stiffness matrices of sheet metal components are usually not variational during the process of tolerance analysis; however, material properties of the compliant parts may change in volume production. The variation of the part thickness changes the part stiffness matrix so that the sensitivity matrix is different from that of the assembly with nominal thickness. The paper proposes an improved sensitivity matrix between the incoming part variation and the assembly variation for the assembly with thickness variation. Moreover, the orthogonal design is used to judge the importance of part and thickness variation for the assembly deviation. The proposed method is illustrated through a case study and the results show that the thickness variation influences the relationship between the part variation and the assembly variation. In addition, part variation plays a more important role to assembly variation than the thickness deviation does according to the orthogonal design.
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Simões, J. A., und M. A. Vaz. „The influence on strain shielding of material stiffness of press-fit femoral components“. Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 216, Nr. 5 (01.05.2002): 341–46. http://dx.doi.org/10.1243/09544110260216612.
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The investigation and development of hip prostheses that can provoke identical strain patterns with those of the intact femur (physiological strains) are challenging design problems that have been addressed by several researchers. The modification of the physiological femoral strain pattern provokes adverse tissue biological reactions such as bone hypertrophy, as well as possible mechanical failure of the bone-implant construction. Investigators have used numerical and experimental methods to study the influence of the prosthesis material and geometry on physiological strain deviation. Within the present study, same geometry femoral components composed of different materials have been analysed using strain gauges. The effect of stem stiffness on the strain deviation relatively to those obtained with the intact femur was assessed. Five similar Freeman's prostheses made of different materials (steel, aluminium, composite and polyurethane) at the proximal and middle distal regions were manufactured and tested. The results revealed that only at the proximal lateral and proximal medial aspects of the femur were some differences observed between the strain patterns of the prostheses studied.
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Krämer, Alexander Maximilian, Johannes Lohmar und Gerhard Hirt. „Precise Prediction of Microstructural Properties with Minimal Experimental Effort for the Nickel-Base Alloy Inconel 718“. Advanced Materials Research 1140 (August 2016): 43–50. http://dx.doi.org/10.4028/www.scientific.net/amr.1140.43.
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The prediction of microstructure evolution in addition to the macroscopic material strength, material flow and temperature evolution is becoming increasingly important as more and more complex materials, with properties that are heavily influenced by their microstructure, are being used. This in turn requires refined microstructure models to be parameterized. Compared to flow curve models, the experimental effort for the parameterization of microstructure models increases due to the inclusion of grain size and recrystallization effects. Therefore plenty of experiments are usually performed to fully characterize the material at hand. The increasing versatility of testing machines, like dilatometry with easily variable temperatures, in addition to the growing expenses that go along with increasing the number of experiments for high cost materials, leads to the question whether performing all those experiments is really justified. In this paper the microstructure model StrucSim is parameterized for the nickel-base alloy Inconel 718 and coupled online with a finite-element (FE) simulation to predict the material behaviour during double compression tests. StrucSim combines multiple constitutive equations into a single consistent material model representing also the microstructure. Therefore these constitutive equations are parameterized to their respective metal-physical phenomena to find the initial parameters for StrucSim. Afterwards the set of final parameters is determined by optimizing the initial parameters using the StrucSim algorithm interconnecting the constitutive equations to define a reference model. The reference model is later compared to different final parameter sets parameterized based on reduced experimental data. Beforehand the reference model is coupled with the FE software Simufact.forming to simulate double compression tests and compare them to experiments as a validation of the reference model. Here forces are predicted with a mean deviation (root of the sum of squared relative errors) of 7.6 % and grains sizes with a mean deviation of about 8 μm from the measurements. Afterwards the influence of reducing the available data during parameterization of StrucSim is investigated to evaluate the possibility of reducing the experimental effort. It is shown that when using only 50 % of the data the quality can be maintained with the reduced model. When simulating the double compression tests a comparable deviation regarding the forces and grain sizes is achieved. Reducing the number of experiments by 50 % during materials characterization therefore appears feasible.
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Devisilov, Vladimir, Yu Novikov und Vadim Bolshakov. „Combined Porous Mesh Metals and Products Made fromThem“. Safety in Technosphere 9, Nr. 2 (16.03.2021): 43–48. http://dx.doi.org/10.12737/1998-071x-2021-9-2-43-48.
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In this paper are considered the essence and design-technological features of products made from new types of porous mesh metals (PMM) based on combination of various permeable and impermeable metallic materials interconnected by hot rolling in the vacuum. To create new materials, a combination of different types of metal grids is used. Therefore, these materials have received the name - combined porous mesh metals (CPMM). The technological problem is to create reliable products with predictable strength, filtration and structural characteristics. The technology of manufacturing products from CPMM is complex and includes a large number of technological operations divided into operations for material manufacture and operations for manufacturing from this material a finished product of required application. Material production includes several operations for preparing the initial metal grids (washing, degreasing, marking-out, grid packaging), and complex technological operations for material manufacturing, consisting in joint the grids and embedded materials between themselves (vacuuming, heating to a predetermined temperature, grid package rolling in vacuum and in hot condition, etc.). Each of technological operations for material manufacturing should be carried out in rigid mode ranges, such as temperature mode, package drafting degree mode, etc. A slight deviation from the mode leads to rejected material or significant deviation from the specified parameters. A difficult problem is the interconnection of metallic grids of various types (distinguishing by thickness, wire diameter, etc.), as well as interconnection of solid metallic embedded elements necessary for products formation from the obtained material. As a result of numerous experiments, it has been able to achieve success and develop the technology for CPMM material manufacturing. The developed material and products made from it have been imbedded at the enterprises of those industries, where highly reliable and efficient constructions, made from permeable materials and having specified functional parameters, are required. A new phase separator filter (PSF) for the fuel tank (FT) of a space item has been created and implemented. Currently, sets including 20 typical sizes of PSF of various modifications are delivered. Using of capillary intakes (CIs) with PSF made from CPMM provides reduction of residual rests of fuel liquid components in fuel tanks. CIs with PSF are almost 2 times lighter than CIs, carried out according to traditional frame-grid design.
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Liu, Gang, Anh-Tuan Vu, Olaf Dambon und Fritz Klocke. „Glass Material Modeling and its Molding Behavior“. MRS Advances 2, Nr. 16 (2017): 875–85. http://dx.doi.org/10.1557/adv.2017.64.
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ABSTRACTPrecision molding is a replicative production method for the mass production of complex glass optics in high precision. In contrast to the traditional material removal process, such as grinding and polishing, the surface as well as the entire shape of the optical component is created by deforming glass at elevated temperatures using precise molding tools with optical surfaces. The molded glass components present high shape accuracy and surface finish after the molding process, therefore no further processing is required. During the molding process, the glass is heated in the molding tool up to above the transition temperature Tg, then pressed into desired shape and cooled down to approximately 200 °C. The precision glass molding is therefore a complex thermo-mechanical process, in which the glass lens undergoes uneven cooling speed and stress distribution. These lead to several drawbacks on the molded glass optics, such as form deviation, index change and fracture. In this study, FEM simulation was employed in order to achieve preliminary understanding of the molding process. The FEM model included viscoelasticity behavior of glass material (stress-relaxation, structure-relaxation and thermos-rheological simplicity), as well as thermodynamics model of the molding machine. In the form of a case study of a real molding example, the form deviation, index change and fracture of the molded glass optic were predicted in advance of the molding experiment by means of the numerical calculation of thermal shrinkage, volume change and stress distribution respectively. The good agreement between simulation results and molding experiment results proves the accuracy of the developed FEM model.
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Liu, Banteng, Junjie Lu, Yourong Chen, Ping Sun, Kehua Zhao, Meng Han, Rengong Zhang und Zegao Yin. „AI-Driven Multiobjective Scheduling Algorithm of Flood Control Materials Based on Pareto Artificial Bee Colony“. Wireless Communications and Mobile Computing 2021 (22.06.2021): 1–15. http://dx.doi.org/10.1155/2021/5557543.
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Considering the competition between rescue points, we use artificial intelligence (AI) driven Internet of Thing (IoT) and regional material storage data to propose a multiobjective scheduling algorithm of flood control materials based on Pareto artificial bee colony (MSA_PABC). To address the scheduling of flood control materials, the multiple types of flood control materials, the multiple disaster sites, and entertain both emergency and fairness of rescue need to be considered comprehensively. The MSA_PABC has the constraints such as storage quantity constraint of warehouse materials, material demand constraint, and maximum transportation distance of flood control materials. We establish the scheduling optimization model of flood control materials for each disaster rescue point and the total scheduling optimization model for all flood control materials. Then, MSA_PABC uses the modified Pareto artificial bee colony algorithm to solve the multiobjective models. Three types of initialization strategies are proposed to calculate the fitness of each rescue point and the overall evaluation value of the food source. We propose the employ bee operations such as niche technology and local search of the variable neighborhood, the onlooker bee operations such as Pareto nondominated sorting and crossover operation, the scout bee operations such as maximum evolutionary threshold, and end elimination mechanism. Finally, our proposed solution obtains the nondominated solution set and its optimal solution. The experimental results show that no matter how the number of rescue points changes, MSA_PABC can find the nondominated solution set and optimal solution quickly. It improves the convergence rate of MSA_PABC and material satisfaction rate. Our solution also reduces the average maximum transportation distance, the standard deviation of maximum transportation distance, and the standard deviation of material satisfaction rate. The evaluation also demonstrates MSA_PABC outperforms the state-of-arts such as ABC (artificial bee colony), NSGA2 (nondominated sorting genetic algorithm 2), and MOPSO (multiobjective particle swarm optimization).
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Li, Zhe, Bin Jiang, Hong Xu Xu und Ming Jia Zhou. „Study of 1Cr18Ni9Ti Material Properties in Cutting Process“. Advanced Materials Research 500 (April 2012): 218–22. http://dx.doi.org/10.4028/www.scientific.net/amr.500.218.
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This paper obtained the mechanical properties of 1Cr18Ni9Ti by the static tensile test, got the corresponding relationship between the 1Cr18Ni9Ti coefficient of linear expansion, thermal conductivity and temperature changes, and simulated the process of 1Cr18Ni9Ti cutting with the finite element simulation software, then analysised the reason why the deviation of the finite element simulation results and measured data increased with the cutting speed improved. These studies provide some important references for the finite element simulation and revealing the tool wear and breakage mechanism.
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Yan, Wen Yi, Qing Ping Sun und Peter D. Hodgson. „A Characteristic of Spherical Indentation Curve and its Application in Measuring Material Properties“. Materials Science Forum 561-565 (Oktober 2007): 2131–34. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.2131.
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The spherical indentation obeys Hertz contact theory when the applied load is within the elastic limit. Once the applied load is over the elastic limit, the indentation curve starts to deviate from the original purely elastic indentation curve. This deviation point, which indicates the start of the nonlinear deformation, is an important characteristic of a spherical indentation curve. The indentation force corresponding to the deviation point is related to a basic material constant, which is the yield stress for an elastic-plastic material or the transformation stress for a shape memory alloy. This relationship can be applied to measure the yield stress or the transformation stress from a simple spherical indentation curve. Detailed discussion on the relationship and the method is presented in this short paper.
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Lamon, Jacques, und Stephane Pompidou. „Micromechanics-Based Evaluation of Interfaces in Ceramic Matrix Composites“. Advances in Science and Technology 50 (Oktober 2006): 37–45. http://dx.doi.org/10.4028/www.scientific.net/ast.50.37.
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Interfaces are a key element in ceramic matrix composites, but also in several material assemblies, such as, for instance, multilayers. This is not only because they can cause crack deflection and make materials damage tolerant, but also because they can be tailored with regard to material performances. An approach to crack deflection at interfaces or within interphases is proposed on the basis of the following Cook and Gordon’s mechanism: a crack is nucleated along an interface, ahead of a propagating crack; deflection of this crack then results from coalescence with the interface crack. The stress state induced by a crack was computed in a cell of bimaterial using the finite element method. The cell represents a matrix and a fiber, or an interphase and a fiber or two layers in a multilayer. A master curve was established. It represents the debonding condition based on strengths and elastic moduli of constituents. Then a deviation potential was defined. Deviation potentials were calculated for various fibre/matrix or layer combinations.
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Lynch, Joanna M., David M. Barbano und J. Richard Fleming. „Determination of the Total Nitrogen Content of Hard, Semihard, and Processed Cheese by the Kjeldahl Method: Collaborative Study“. Journal of AOAC INTERNATIONAL 85, Nr. 2 (01.03.2002): 445–55. http://dx.doi.org/10.1093/jaoac/85.2.445.
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Abstract The objective of this collaborative study was to determine interlaboratory performance statistics for a modified and optimized version of AOAC Method 920.123 for the determination of the total nitrogen content of hard, semihard, and processed cheese by Kjeldahl analysis. Details included addressing the issues of material homogeneity, test portion size (1 g), quantitative transfer (weighing on to filter paper), ensuring system suitability (nitrogen recoveries), and using AOAC Method 991.20 as the basis for nitrogen analysis. Fifteen laboratories tested 18 pairs of blind duplicate cheese materials with a crude protein content between 18 and 36%. Materials represented hard, semihard, and processed commercial cheeses with a wide range of composition. Statistical performance parameters expressed as crude protein (nitrogen × 6.38), g/100 g, with invalid and outlier data removed were mean = 26.461, repeatability standard deviation (Sr) = 0.111, reproducibility standard deviation (SR) = 0.153, repeatability relative standard deviation (RSDr) = 0.42%, reproducibility relative standard deviation (RSDR) = 0.58%, repeatability (r) = 0.312, and reproducibility (R) = 0.428. The interlaboratory study results were acceptable and comparable to those for the milk Kjeldahl nitrogen method on a relative nitrogen basis. The Study Directors recommend that this modified method for the determination of total nitrogen in hard, semihard, and processed cheese by Kjeldahl analysis be adopted First Action as an improved method to replace Method 920.123.
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Liu, Y. C. „The Effect of Restraining Force on Shape Deviations in Flanged Channels“. Journal of Engineering Materials and Technology 110, Nr. 4 (01.10.1988): 389–94. http://dx.doi.org/10.1115/1.3226067.
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Quantitative relationships have been obtained between restraining force and shape deviations, such as springback and side wall curl, in flanged channels made of SKDQ and high strength streets. It is observed that shape deviation is greatly reduced if the applied restraining force is beyond the yield strength of the material. However, due to the restriction of die entrance and punch corners, this condition cannot be readily achieved in the conventional bead system as side wall fracture intervenes. To circumvent this constraint, a so-named “intermediate restraining” process has been developed to form high quality flanged channels in one single operation. The suggested process is displacement controlled and, in practice, should be applicable to any material once its physical properties are known.
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Pulliainen, T. Katrdna, und Harriet C. Wallin. „Determination of Total Phosphorus in Foods by Colorimetric Measurement of Phosphorus as Molybdenum Blue after Dry-Ashing: NMKL1 Interlaboratory Study“. Journal of AOAC INTERNATIONAL 77, Nr. 6 (01.11.1994): 1557–61. http://dx.doi.org/10.1093/jaoac/77.6.1557.
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Abstract A spectrophotometric method in which the sample is dry-ashed in the presence of zinc oxide, and total phosphorus content is measured colorimetrically as molybdenum blue was evaluated by 12 participating laboratories from the Nordic countries. The study included potato flour, sausage, cold ham, infant formula powder, cheese, and skimmed milk powder. The materials were presented to the participants as 12 randomly coded samples of 2 blind duplicates of each material. The phosphorus content of the materials varied between 0.076 and 0.96 g/100 g. The relative standard deviation for repeatability of the method varied from 1.1% for 0.96 g phosphorus/100 g to 5.4% for 0.29 g phosphorus/100 g. The relative standard deviation for reproducibility varied from 3.6% for 0.96 g phosphorus/100 g to 7.7% for 0.23 g phosphorus/100 g.
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Yu, Feng Yun, Chuan Xu Zhang und Miao Wu. „On Damage Evaluation Method of the Ferromagnetic Material Based on Weak Magnetic Field Detection Technology“. Key Engineering Materials 324-325 (November 2006): 331–34. http://dx.doi.org/10.4028/www.scientific.net/kem.324-325.331.
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The increase of magnetic field of ferromagnetic components under service load and geomagnetic field is induced by the residual magnetic induction and spontaneous magnetization. The stress concentration positions can be found by detecting the magnetic field and the fracture can be avoided. The variation of the residual magnetic intensity of bearing carriers under different damage conditions is studied in this paper; the statistical characteristic of the residual magnetic intensity of the specimens in different residual deformations is got, and a concept of residual magnetic intensity standard deviation is put forward with a lot of experiments and in-depth theoretic analysis. The results indicate that the curves of residual magnetic intensity standard deviation appear obvious turning points when the specimens reach the yield point in different original magnetic field conditions, and that the function between residual magnetic intensities standard deviation, tensile load and strain is established. Therefore, the plastic deformation can be judged by the variation of the magnetic field in their service process, and the damage level can be evaluated consequently, which gives a new reliable method to estimate the deformation of ferromagnetic material.
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Ginat, Daniel Thomas, und Gregory Christoforidis. „A printed information leaflet about MRI and radiologists improves neuroradiology patient health literacy“. Neuroradiology Journal 31, Nr. 6 (12.07.2018): 609–13. http://dx.doi.org/10.1177/1971400918788361.
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Purpose To determine the health literacy benefit of a printed informational leaflet for patients scheduled to undergo brain magnetic resonance imaging (MRI) scans. Methods and materials A two-page leaflet that provided an overview of MRI and the role of radiologists was prepared and given to outpatients scheduled to undergo brain MRI examinations while in the waiting room. A survey composed mainly of yes/no and Likert scale questions pertaining to the leaflet, as well as patient demographics, was administered to the patients. Results A total of 147 patients completed the survey, of which 110 (75%) had undergone a prior MRI scan, 120 (82%) stated that their ordering provider explained the reason for the MRI scan, and less than 1% reported having referenced online resources related to MRI. The average score for how well patients understood the MRI scan procedure and how it is reviewed was 4.16/5 (standard deviation 1.18) before versus 4.39/5 (standard deviation 1.08) after reading the leaflet, which was a statistically significant improvement based on the Wilcoxon signed-rank test ( P < 0.01). The score for how helpful the reading material was for explaining what is MRI was 4.06/5 (standard deviation 1.02) and the score for how helpful the reading material was for explaining what is a radiologist was 4.18/5 (standard deviation 0.98). Conclusion A printed leaflet about MRI and radiologists can serve as an opportunity to educate patients about certain aspects of their scans during their stay in the waiting room.
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Yu, Feng Yun, und J. C. Zhang. „Magnetic Test Method Used to Identify Plastic Deformation of Ferromagnetic Material“. Advanced Materials Research 670 (März 2013): 97–100. http://dx.doi.org/10.4028/www.scientific.net/amr.670.97.
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Metal magnetic memory testing (MMMT) technique is a kind of new NDT technique. It is interested by NDT area in recent years for its own advantages: early diagnosis, preventing sudden fatigue failure of equipments and the testing samples do not need to be magnetized. In order to find out the variation law of the residual magnetic strength of ferromagnetic material processed by different cutting method, axial tension tests about milling and flat surface grinding samples are completed in elastic and plastic deformation phase. The experimental results indicate that the magnetic strength variation law of two kinds of sample makes a great difference in the same deformation phase. The magnetic strength and standard deviation variation law of the grinding and milling samples are almost reverse. But there is a common ground of the two samples that when the material reaches yield phase, turning point occurs on both the residual magnetic strength and standard deviation curve. So we can identify whether there is plastic deformation according to the residual magnetic strength variation law of ferromagnetic material.
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Mital, Pratik, Marc Goetschalckx und Edward Huang. „Robust material handling system design with standard deviation, variance and downside risk as risk measures“. International Journal of Production Economics 170 (Dezember 2015): 815–24. http://dx.doi.org/10.1016/j.ijpe.2015.02.003.
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Marcel, Reymus, Hickel Reinhard und Keßler Andreas. „Accuracy of CAD/CAM-fabricated bite splints: milling vs 3D printing“. Clinical Oral Investigations 24, Nr. 12 (21.05.2020): 4607–15. http://dx.doi.org/10.1007/s00784-020-03329-x.
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Abstract Objectives The aim of this study was to investigate the accuracy of CAD/CAM-fabricated bite splints in dependence of fabrication method (milling vs 3D printing), positioning (horizontal vs vertical), selection of material, and method of deviation measurement. Materials and methods Bite splints were 3D-printed in either horizontal or vertical position (n = 10) using four different resins (Dental LT, Ortho Clear, Freeprint Splint, V-Splint). As control, ten bite splints were fabricated by CNC milling (ProArt CAD Splint). The splints were scanned and deviations between the CAD-file (trueness) and between each other within one group (precision) were measured by two different software applications and methods (cloud-to-cloud vs cloud-to-mesh). Data were analyzed using univariate analysis, Kolmogorov-Smirnov, Kruskal-Wallis, and Mann-Whitney U tests. Results The highest impact on accuracy was exerted by the selection of the material (trueness: ηP2 = 0.871, P < 0.001; precision: ηP2 = 0.715, P < 0.001). Milled splints showed the highest trueness (P < 0.01) but not the highest precision at the same time. Horizontally positioned 3D-printed bite splints showed the least deviations in terms of trueness while vertical positioning resulted in the highest precision. The cloud-to-cloud method showed higher measured deviations than the other methods (P < 0.001–P = 0.002). Conclusion Milled splints show higher trueness than 3D-printed ones, while the latter reveal higher reproducibility. The calculated deviations vary according to the measurement method used. Clinical relevance In terms of accuracy, milled and 3D-printed bite splints seem to be of equal quality.
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Valentino, Tobias, Marian Höhmann, Kevin Schünemann, Jonas Wentzler, Tim Wünderlich, Tim Radel und Frank Vollertsen. „Time-Resolved Force Measurements to Determine Positioning Tolerances for Impulse-Based Indentations“. Lasers in Manufacturing and Materials Processing 8, Nr. 2 (31.05.2021): 216–35. http://dx.doi.org/10.1007/s40516-021-00140-8.
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AbstractHigh-throughput experimentation methods determine characteristic values, which are correlated with material properties by means of mathematical models. Here, an indentation method based on laser-induced shock waves is presented, which predicts the material properties, such as hardness and tensile strength, by the induced plastic deformation in the substrate material. The shock wave pushes a spherical indenter inside a substrate material. For reproducible indentations, the applied load is of importance. To compare different processes and process parameters, the measured plastic deformation is normalized by the applied load. However, eccentric irradiation leads to altered beam profiles on the surface of spherical indenters and the angle of incidence is changed. Thus, the influence of eccentric irradiation is studied with an adapted time-resolved force measurement setup to determine the required positioning tolerances. The spherical indenter is placed inside a cylindrical pressure cell to increase the laser-induced shock pressure. From the validated time-resolved force measurement method we derive that deviations from the indentation forces are acceptable, when the lateral deviation of the beam center, which depends only on the alignment of the setup, does not exceed ± 0.4 mm. A vertical displacement from the focus position between -3.0 mm and + 2.0 mm still leads to acceptable deviations from the indentation force.
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Bell, Raoul, Jan P. Röer, John E. Marsh, Dunja Storch und Axel Buchner. „The Effect of Cognitive Control on Different Types of Auditory Distraction“. Experimental Psychology 64, Nr. 5 (September 2017): 359–68. http://dx.doi.org/10.1027/1618-3169/a000372.
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Abstract. Deviant as well as changing auditory distractors interfere with short-term memory. According to the duplex model of auditory distraction, the deviation effect is caused by a shift of attention while the changing-state effect is due to obligatory order processing. This theory predicts that foreknowledge should reduce the deviation effect, but should have no effect on the changing-state effect. We compared the effect of foreknowledge on the two phenomena directly within the same experiment. In a pilot study, specific foreknowledge was impotent in reducing either the changing-state effect or the deviation effect, but it reduced disruption by sentential speech, suggesting that the effects of foreknowledge on auditory distraction may increase with the complexity of the stimulus material. Given the unexpected nature of this finding, we tested whether the same finding would be obtained in (a) a direct preregistered replication in Germany and (b) an additional replication with translated stimulus materials in Sweden.
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Sheu, Jinn Jong, Dong Mei Xu und Chin Wei Liu. „Cutting Force and Tool Deflection Predictions for High Speed Machining of Hard to Cut Material“. Advanced Materials Research 154-155 (Oktober 2010): 1157–64. http://dx.doi.org/10.4028/www.scientific.net/amr.154-155.1157.
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The dimension accuracy and the too life are the major issues of the machining of hard-to-cut materials. To fulfill the requirements of accuracy and tool life needs not only well planning of cutting path but also the proper cutting conditions of cutters. The vibration and deflection of cutters caused by poor selection of cutting conditions can be predicted using models of cutting force and tool deflection. In this paper, a cutting force model considering the effect of tool helical angle and a cantilever beam model of tool deflection were proposed for the high speed machining of hard-to-cut material SKD11. The shearing force, the plowing forces, and the helical angle of cutters are considered in the elemental force model. The material of workpiece, SKD11, studied in this paper is commonly used for the die and mold industries. The cutting constants of the proposed force model are determined via the cutting experiments carried out on a high speed machining center. A dynamometer and a high frequency data acquisition system were used to measure the x-, y-, and z-direction cutting forces. The obtained cutting constants were used to predict the cutting forces and compared with the results obtained from the cutting experiment of verification using cutters with different helical angles. The theoretical and the experimental cutting forces in the x-, y-, and z- direction are in good agreement using flat cutters with 30 and 45 degrees of helical angle. The dimension deviations of the cut surface in the cutting experiment case of tool deflection were measured using a touch probe and an infrared receiver installed on the machining center. The measured average dimension deviation, 0.163mm, is close to the predicted tool deflection, 0.153mm, using the proposed cantilever beam model. The comparisons of the cutting forces and the average of the cut surface dimension deviation are in good agreement and verify the proposed cutting force and the tool deflection models are feasible and useful.
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Shi, Zeyun, Jinkeng Lin, Jiong Chen, Yao Jin und Jin Huang. „Symmetry Based Material Optimization“. Symmetry 13, Nr. 2 (14.02.2021): 315. http://dx.doi.org/10.3390/sym13020315.
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Many man-made or natural objects are composed of symmetric parts and possess symmetric physical behavior. Although its shape can exactly follow a symmetry in the designing or modeling stage, its discretized mesh in the analysis stage may be asymmetric because generating a mesh exactly following the symmetry is usually costly. As a consequence, the expected symmetric physical behavior may not be faithfully reproduced due to the asymmetry of the mesh. To solve this problem, we propose to optimize the material parameters of the mesh for static and kinematic symmetry behavior. Specifically, under the situation of static equilibrium, Young’s modulus is properly scaled so that a symmetric force field leads to symmetric displacement. For kinematics, the mass is optimized to reproduce symmetric acceleration under a symmetric force field. To efficiently measure the deviation from symmetry, we formulate a linear operator whose kernel contains all the symmetric vector fields, which helps to characterize the asymmetry error via a simple ℓ2 norm. To make the resulting material suitable for the general situation, the symmetric training force fields are derived from modal analysis in the above kernel space. Results show that our optimized material significantly reduces the asymmetric error on an asymmetric mesh in both static and dynamic simulations.
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CHAFAI, Mahfoud, Abderrahmane OUADI und Hamid BENTARZI. „PLC-Based Safety Instrumented System of a Boiler using HAZOP“. Algerian Journal of Signals and Systems 3, Nr. 1 (15.03.2018): 1–9. http://dx.doi.org/10.51485/ajss.v3i1.53.
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HAZOP Analysis is used to determine great deviations which will affect the operational safety of a boiler of an existing petrochemical plant that may affect on persons, material and the environment. PLC is proposed to provide the safety function to fit into the overall machine control system as a safety-related part. It reads from the temperature, pressure sensors via its input interface modules and outputs commands in the case of critical deviation via the output module to the final control elements such as actuators allowing an improvement in the safety of the overall boiler system.
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Everhart, Wesley, und Joseph Newkirk. „Grain Size Effects in Selective Laser Melted Fe-Co-2V“. Applied Sciences 9, Nr. 18 (06.09.2019): 3701. http://dx.doi.org/10.3390/app9183701.
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The material science of additive manufacturing (AM) has become a significant topic due to the unique way in which the material and geometry are created simultaneously. Major areas of research within inorganic materials include traditional structural materials, shape memory alloys, amorphous materials, and some new work in intermetallics. The unique thermal profiles created during selective laser melting (SLM) may provide new opportunities for processing intermetallics to improve mechanical and magnetic performance. A parameter set for the production of Fe-Co-2V material with additive manufacturing is developed and efforts are made to compare the traditional wrought alloy to the AM version of the same chemistry. Evaluation includes magnetic properties, composition, and phase as a function of thermal history, as well as mechanical performance. Results show significant similarities in microstructure between AM and wrought materials, as well as mechanical and magnetic performance. Property trends are evaluated as a function of grain size and show effects similar to the Hall–Petch strengthening observed in wrought material, though with some underprediction of the strength. Magnetic properties qualitatively follow the expected trends but demonstrate some deviation from wrought material, which is still unexplained.
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Wang, Bo, Yong Zhang und Rong Jun Chen. „Experimental and Numerical Simulation of Absorbing Property of Cement-Based Material Blending with Nano-TiO2 and Steel Fibers“. Applied Mechanics and Materials 442 (Oktober 2013): 83–87. http://dx.doi.org/10.4028/www.scientific.net/amm.442.83.
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The absorbing performance have been tested and analyzed by taking cement as matrix, blending material nanoTiO2 and steel fibers for absorbing agent trial Sample, in the 8 ~ 18 GHz frequency band, the results indicate that nanoTiO2 and steel fibers and composite cement which made of absorbing material has good absorbing property. Blending material absorbing properties of cement-based materials, the impact must be considered together, not the more the better, when blending material exceeding 6wt%, its ability of wave-transparent enhance while absorbing property will be reduced finally. By using ANSYS software for computer simulation of the specimen to test experimental data and found the computer simulation algorithm not only can verify the correctness of the conclusion but also auxiliary correction deviation appeared in the course of the real data and the error value.