Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Infrared scanning thermography for a quantitative detection of cavities in a plane slab and a rectangular prism (1982)
    Springer
    Journal of nondestructive evaluation 3 (1982), S. 99-109 
    Details
    ISSN: 1573-4862
    Keywords: thermography ; infrared scanning ; calibration ; inverse problems ; cavity detection ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract An approach for treating nondestructive testing as the solution of inverse problems in mathematical physics has been used for the detection of cavities. The approach is developed based on the use of an additional boundary condition of scanned temperature on the surface to solve for the cavity geometry. For the present study, the condition at the cavity side is taken to be that of a specified temperature, and the experiment is carried out to meet this condition. Two specimens are tested in this paper, a plane slab and a rectangular prism. In both bodies the cavity is rectangular in shape. For the testing of the plane slab, the method is able to detect the cavity wall with high accuracy, whereas the cavity depth error is larger (6%). The detection of the cavity position in the rectangular prism has an error ranging from −9.7 to 7.7%. Errors in the experiment are attributed to the uncertainties in the measurements of temperature and the Biot number. The former is read off from the analog data output of the infrared scanner. The latter is not measured separately, but is computed from the scanned data and thus becomes a portion of the total nondestructive testing output. A final note is also made in this paper to relate how the presented method can be used in actual practice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00568966
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    An inverse problem technique for detecting irregular cavities in circular cylinders by infrared scanning (1984)
    Springer
    Journal of nondestructive evaluation 4 (1984), S. 133-140 
    Details
    ISSN: 1573-4862
    Keywords: Thermography ; infrared scanning ; calibration ; inverse problem ; cavity detection ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract An inverse problem technique has been developed for detecting irregular cavities in circular cylinders. In this method, the cavity is considered a part of the unknown geometry of the investigated system, and the evaluated temperature is used to locate this geometry. An auxiliary problem is introduced in the solution of this problem; and in the solution, the cavity wall is located by forcing the temperature to satisfy the condition imposed at the cavity. The new methodology is validated by an experiment presented in this paper, and the test results indicate that this method is highly successful in locating cavities. The accuracy of the method is closely related to the accuracy of the temperature that can be measured at the surface. A small error in the surface temperature results in a slight cavity error for deep cavities, while a shallow cavity is not severely affected by a surface temperature error. This method is particularly attractive in detecting shallow cavities in nondestructive evaluation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00566218
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Estimation of parameters where dependent observations are related by equality constraints (1984)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 30 (1984), S. 747-757 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Pirt's model for microbial growth and product formation are reparameterized to obtain multiresponse models with common parameters. The dependent variables in the models are related through the available electron and carbon balance constraints. Covariance adjustment is used to reduce the growth model to a unit variate linear model with covariates. Therefore, standard multiple regression programs can be used to obtain combined point and interval estimates of true biomass energetic yield, true product yield and maintenance coefficient. This approach may yield “better” estimates than the maximum likelihood approach when an appropriately selected subset of covariates is used. Nonlinear estimation procedures are also considered; these procedures are efficient with few responses; however, as the number of responses per observation increase, they may require a lot of computing time. For illustration several data from the biochemical engineering literature are analyzed by the proposed methods.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690300508
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Influence of processing on quality of injection-compression-molded disks (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1206-1212 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A modified injection molding machine with a compression mechanism, and a mold with a movable wall and shut-off mechanism, were used to investigate the effects of processing parameters on the quality of injection-compression-molded polystyrene disks. The compression start-up time, compression force, melt temperature, and part thickness were selected processing parameters. The disk moldings were evaluated based on dimensional accuracy and birefringence. It is found that the compression start-up time affects packing time, and thus greatly affects the residual orientation. If the transition from packing to compression could start before peak cavity pressure, disks with low residual orientation could be obtained. High compression force improves part quality and reduces thickness. Since both compression-induced reduction and cooling-induced shrinkage are involved, the effects of temperature and thickness are not as straightforward as the trends in conventional injection molding.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351503
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Studies on VOCl3/MgCl2/NaY/Al2Et3Cl3 complex support catalysts for the copolymerization of ethylene and propyleneThe work was financed by National Natural Science Foundation of China. (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 54 (1994), S. 1403-1408 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Using VO2+ as a spin probe, a new method to obtain microenvironmental information on supports was developed which can be used in the choice of supports for coordination catalysts. Utilizing the above method, NaY was chosen as second support component. A complex support catalyst VOCl3/MgCl2/NaY/Al2Et3Cl3 was prepared and used in ethylene-propylene copolymerization. Higher polymerization activity was obtained with this catalytic system. Alternating the ratio of two kinds of supports, the composition and sequence structure of copolymers could be controlled, which showed that NaY participated in the active species, affected the insertion of monomer, and changed the composition and sequence structure of copolymers. © 1994 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1994.070541003
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Preparation of gradient-index (GRIN) polymer fibers for imaging applications (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 60 (1996), S. 1379-1383 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A closed extrusion process combined with a core-shell separation die design is developed in this study for preparing gradient index (GRIN) polymer fibers with a quadratic distribution of the refractive index. The material system used in this investigation is methyl methacrylate (MMA, n = 1.49) and benzyl methacrylate (BzMA, n = 1.568). The refractive index differences between the center and the periphery (Δn) of the prepared polymer fibers increase from 0.0115 to 0.020 when BzMA in the reactant mixtures increases from 17 to 28%. This finding would suggest that increasing the high refractive index monomer in the reactant mixture increased Δn. The Δn values decrease from 0.018 to 0.0135 when the diffusion zone temperature increases from 70 to 90°C. The diffusion rates of the monomers increase with the temperature, thereby causing BzMA and MMA to distribute more uniformly at a higher temperature than at a lower one. This uniform distribution leads to the decrease of Δn with an increasing temperature. The prepared GRIN polymer fibers have potential applications as imaging lenses for scanners, fax machines, and copiers. © 1996 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 7
    Electronic Resource
    Electronic Resource
    Solvent effect on the action of ethylene-vinyl acetate copolymer pour point depressant in waxy solutions (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 60 (1996), S. 1575-1578 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The flowability and thermal behavior of waxy solutions with and without an ethylene-vinyl acetate copolymer (EVA) have been studied. The drastic changings of pour point depression (ΔTpp) and the crystallization in four waxy solutions were observed. These changes were linear with the U-interaction parameters between EVA and wax in different solvents, suggesting that the efficiency of EVA pour point depressent depends on its compatibility with wax, which is affected by solvent. © 1996 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 8
    Electronic Resource
    Electronic Resource
    Studies on the preparation of gradient-index polymeric rods by interfacial-gel copolymerization (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 56 (1995), S. 1179-1182 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070560918
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Experimental study on the effects of adding compression to injection molding process (1995)
    Hoboken, NJ : Wiley-Blackwell
    Advances in Polymer Technology 14 (1995), S. 15-24 
    Details
    ISSN: 0730-6679
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The quality of thermoplastic injection molded parts is mainly determined during the post-filling process. To enhance the control capacity over the post-filling process, adding compression to the conventional injection molding process opens a flexible channel for pressure control. This study experimentally investigated the effects of adding compression on the thermal-mechanical history and on the quality of molded parts. An instrumented molding machine with a compression mechanism was used. Molds for rectangular plate and circular disk were equipped with a movable cavity wall and shut-off mechanism. The thermomechanical history during the injection compression molding was identified with the aid of a PC-based data acquisition system. The quality of parts was evaluated by flatness, deviation from mold dimensions, and birefringence. It has been found that the thermomechanical history of the melt under injection compression molding follows a quadrilateral-shaped path over the p-v-T diagram. The control capacity over post-filling is enhanced. It thus can produce parts with better dimensional control with less frozen-in orientation than those from conventional injection molding. © 1995 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/adv.1995.060140102
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Development of moldability diagrams for gas-assisted injection molding (1995)
    Hoboken, NJ : Wiley-Blackwell
    Advances in Polymer Technology 14 (1995), S. 197-205 
    Details
    ISSN: 0730-6679
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Gas-assisted injection molding (GAIM) has proven itself to be a breakthrough in molding technology. However, the process involves additional gas-related parameters to control the molding process. The interaction between melt and gas makes the gas-assisted process complicated. To make satisfactory parts, the material, the mold, and process parameters determine the “moldability” of a specific system. The concept of “molding areas” on the critical plane can be extended from thermoplastic injection molding to GAIM. This research is devoted to the development of a proper moldability diagram for GAIM. The first part of this study employs gas-related parameters to define the molding area. The second part is devoted to identifying the relative importance of process parameters. The results show that melt temperature and short shot are the two factors which most significantly affect the GAIM process. The third part of this study defines the moldability based on critical parameters. The application of the moldability concept is demonstrated in selecting the optimum rib geometry. These moldability studies are intended to give first guidelines for system optimization. © 1995 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/adv.1995.060140303
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...