Mechanical Modeling and Characterization of the Curing Process of Underfill Materials

2002 ◽  
Vol 124 (2) ◽  
pp. 97-105 ◽  
Author(s):  
L. J. Ernst ◽  
C. van ’t Hof ◽  
D. G. Yang ◽  
M. S. Kiasat ◽  
G. Q. Zhang ◽  
...  
Keyword(s):  
Operating Conditions ◽  
Stress And Strain ◽  
Electronic Packages ◽  
Curing Process ◽  
Strain Fields ◽  
Starting Point ◽  
Polymer Curing ◽  
The Impact ◽  
Insight Into

Thermo-setting polymers are widely used as underfill materials to improve the reliability of electronic packages. In the design phase, the influence of underfill applications on reliability is often judged through thermal and mechanical simulations, under assumed operating conditions. Because of lacking insight into the mechanical processes due to polymer curing, the impact of processing induced residual stress fields is often neglected. To investigate the evolution of stress and strain fields during the curing process it is important to assume a more appropriate starting point for subsequent process modeling. Furthermore, study of possible damage originating from the fabrication process then comes within reach. To facilitate future analysis of stress and strain fields during the curing process a cure dependent constitutive relation is assumed. An approximate investigation method for the process-dependent mechanical properties, based on Dynamic Mechanic Analysis (DMA), is developed. As an illustration the parameter identification is performed for a selected epoxy resin.

scholarly journals Branding post-communist Romania and its effects on country image

2017 ◽  
Vol 11 (1) ◽  
pp. 504-512
Author(s):  
Anca-Georgiana Andrei
Keyword(s):  
Nation Branding ◽  
Country Image ◽  
National Image ◽  
Competitive Edge ◽  
Second Stage ◽  
Starting Point ◽  
Weak Points ◽  
National Reputation ◽  
The Impact ◽  
Insight Into

Abstract In recent years, more precisely from 1989 on, which was considered by a lot of experts the beginning of the second stage of globalization, nation branding campaigns have started to be launched in more and more countries in order to help developing nations image and reputation and to provide a competitive edge on economic, social and even political areas. Simon Anholt and Wally Olins are the two authors who studied the most nation branding phenomenon and came up with theories which were applied often by professionals when elaborating nation branding campaigns for different states. Nadia Kaneva, Keith Dinnie, Melissa Aronczyk, Luminita Nicolescu and Alina Dolea have also focused their researches on this theme and manage to contribute with new and interesting ideas to the field. This paper provides insight into the most important nation branding campaigns made by Romania starting from 1989 until present. Through a comparative analysis of those campaigns the paper tries to identify which was their impact on Romania’s image or reputation. How was Romania perceived (from the image perspective) before 1989 at international level? Did the image change after 1989? And what was the impact of the most important branding nation campaigns implemented after 1989 in the image of Romania and implicit in economy? These are the main questions this paper tries to answer. At the same time, the study also explores briefly the concept of globalization, nation branding, national image and national reputation. The conclusions of the paper will provide in the end a general background of all studied nation branding campaigns which will include the similarities and differences between them, but also both strong and weak points. Its aim is to contribute, among other existing papers, as a starting point for researchers or professionals who want to elaborate nation branding strategies for Romania or other countries.

Effect of Rotor-Stator Configuration in the Generation of Vortical Scales and Wake Mixing in Single Stage Axial Fans: Part II — Assessment of Vortex Sound Sources

2013 ◽  
Author(s):  
Mónica Galdo Vega ◽  
Jesus Manuel Fernandez Oro ◽  
Katia María Argüelles Díaz ◽  
Carlos Santolaria Morros
Keyword(s):  
Deep Understanding ◽  
Operating Conditions ◽  
Axial Fan ◽  
Noise Sources ◽  
Sound Sources ◽  
Time Resolved ◽  
Vortex Sound ◽  
Starting Point ◽  
Axial Fans ◽  
The Impact

This second part is devoted to the identification of vortex sound sources in low-speed turbomachinery. As a starting point, the time-resolved evolution of the vortical motions associated to the wake shear layers (reported in the first part of the present study) is employed to obtain vorticity distributions in both blade-to-blade and traverse locations throughout the axial fan stage. Following, the Powell analogy for generation of vortex sound is revisited to obtain the noise sources in the nearfield region of the fan. Both numerical and experimental databases presented previously are now post-processed to achieve a deep understanding of the aeroacoustic behavior of the vortical scales present in the flow. A LES simulation at midspan, using a 2.5D scheme, allows an accurate description of the turn-out time of the shedding vortices, within high-density meshes in the blades and vanes passages, and a correct modeling of the dynamics of turbulence. Besides, thermal anemometry has been employed with a two-wire probe to measure the planar flow in the midspan sections of the fan. Statistical procedures and signal conditioning of velocity traces have confirmed experimentally the unsteady flow patterns devised in the numerical model. The comparison of the rotor-stator and the stator-rotor configurations provides the influence of the wake mixing and the nucleation of turbulent spots in the distribution of the Powell source terms. Moreover, the relation between the turbomachine configuration and the generation of vortex sound can be established, including the impact of the operating conditions and the contributions of the interaction mechanisms.

Dynamic Analysis of Mechanical Systems With Clearances—Part 1: Formation of Dynamic Model

1971 ◽  
Vol 93 (1) ◽  
pp. 305-309 ◽  
Author(s):  
S. Dubowsky ◽  
F. Freudenstein
Keyword(s):  
Equations Of Motion ◽  
Operating Conditions ◽  
Coupled Systems ◽  
Dynamical Response ◽  
Dynamic Force ◽  
Dynamical Equations ◽  
Mechanical Joint ◽  
The Impact ◽  
Insight Into

A mathematical model of an elastic mechanical joint with clearances has been formulated and the dynamical equations of motion derived (Part I). The model, which we have called an Impact Pair, is basic to the determination of the dynamical response of mechanical and electromechanical systems with clearances, including determination of dynamic force amplification, frequency response, time-displacement characteristics, and other dynamic characteristics. Whenever possible, the results for the impact pair under various operating conditions are illustrated by graphs, which may also offer some insight into the behavior of clearance-coupled systems.

A Nonlinear Elastic Model for Isotropic Materials With Different Behavior in Tension and Compression

1982 ◽  
Vol 104 (1) ◽  
pp. 26-28 ◽  
Author(s):  
Gianluca Medri
Keyword(s):  
Mechanical Characterization ◽  
Three Dimensional ◽  
Small Deformation ◽  
Stress And Strain ◽  
Elastic Model ◽  
Strain Fields ◽  
Isotropic Materials ◽  
Tension And Compression ◽  
Nonlinear Elastic

This note presents a model suitable for the mechanical characterization of isotropic materials with different behavior in tension and compression. The model has been derived from the nonlinear elastic theory and elaborated to adapt it to the small deformation field; the constitutive relation may reliably correlate stress and strain fields even in three-dimensional elastic problems.

Advanced OEH Methodology for Evaluation of Microelectronics and Packaging

2002 ◽  
Author(s):  
Cosme Furlong ◽  
Ryszard J. Pryputniewicz
Keyword(s):  
New Technologies ◽  
Operating Conditions ◽  
Phase Correlation ◽  
Field Of View ◽  
Electronic Packages ◽  
Full Field ◽  
Actual Operating ◽  
Microelectronics Industry ◽  
Microelectronic Components

With the microelectronics industry being one of the most dynamic, in terms of new technologies, electronic packages have to be designed and optimized for new and ever more demanding applications in relatively short periods of time. In addition, for certain applications, the nondestructive testing (NDT) of electronic packages may be needed, especially for applications requiring noninvasive, full-field-of-view, real-time testing the behavior of a specific package subjected to actual operating conditions. This type of NDT can be accomplished by application of optical techniques and, in particular, speckle phase correlation techniques in the form of optoelectronic holography (OEH). In this paper, advanced OEH techniques are described and representative applications of OEH for the effective characterization of microelectronic components and packages are presented.

scholarly journals Towards a Valorization of Corn Bioethanol Side Streams: Chemical Characterization of Post Fermentation Corn Oil and Thin Stillage

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3549 ◽  
Author(s):  
Gabriella Di Lena ◽  
Petra Ondrejíčková ◽  
Josè Sanchez del Pulgar ◽  
Veronika Cyprichová ◽  
Tomáš Ježovič ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Corn Oil ◽  
Chemical Characterization ◽  
Acid Value ◽  
Operating Conditions ◽  
Thin Stillage ◽  
Long Term Study ◽  
Starting Point

First-generation biofuel biorefineries may be a starting point for the development of new value chains, as their by-products and side streams retain nutrients and valuable molecules that may be recovered and valorized for high-value applications. This study provides a chemical characterization of post-fermentation corn oil and thin stillage, side streams of dry-grind corn bioethanol production, in view of their valorization. An overall long-term study was conducted on the two co-products collected over 1 year from a bioethanol plant. Water content, acid value, sedimentation, mineral composition, and fatty acid profiles were analyzed on post-fermentation corn oil. Results highlighted that its acid value was high (19.72–24.29 mg KOH/g), indicating high levels of free fatty acids, but stable over the year due to standardized operating conditions. The fatty acid profile was that typical of corn oil, with a prevalence of linoleic (54–59% of total fatty acids) over oleic (23–27%) and palmitic (12–17%) acids. Macronutrients, fatty acid, and mineral profiles were investigated in thin stillage. Results revealed the acidic pH (4.05–4.68) and high dilution (90–93% water) of this side stream. The dry mass was composed of fats (19–30%), proteins (8.8–12.8%), ash (8.7–9.5%), and fiber (7.3–9.8%). The concomitant presence of a variegate complex of molecules of nutritional interest in corn bioethanol co-products, with several potential high-value market applications, make the perspective of their recovery a promising strategy to create new cross-sector interconnections according to circular economy principles.

scholarly journals Removal of nickel through sulfide precipitation and characterization of electroplating wastewater sludge

2020 ◽  
Vol 55 (4) ◽  
pp. 345-357
Author(s):  
Sarah Jerroumi ◽  
Mohammed Amarine ◽  
Hassan Nour ◽  
Brahim Lekhlif ◽  
Jamal Eddine Jamal
Keyword(s):  
Removal Efficiency ◽  
Metal Removal ◽  
Operating Conditions ◽  
Wastewater Sludge ◽  
Complexing Agents ◽  
Optimal Dosage ◽  
Electroplating Wastewater ◽  
Sulfide Precipitation ◽  
The Impact

Abstract This work consists of the removal of nickel by sulfide precipitation from industrial electroplating wastewater and characterization of the produced sludge. Tests are carried out in a perfectly stirred batch reactor on electroplating industrial solution and synthetic solution prepared in the laboratory. The aim is to evaluate the impact of complexing agents formed during precipitation of metal ions in the industrial effluent. The concentration of nickel in both solutions is 100 mg/L. The operating conditions for the sulfide precipitation process are optimized: pH, molar ratio [S=]/[Ni2+] and dosage of S= ions. For an initial pH of 5 and an equimolar ratio of [S=]/[Ni2+]:1/1, the results show that the removal efficiency of Ni2+ ions is approaching 91 and 94% for industrial and synthetic solutions, respectively. Otherwise, for the same pH value in supersaturation conditions ([S=]/[Ni2+]:1.5/1), the removal efficiency is approaching 62 and 92% for industrial and synthetic solutions, respectively. For an effective metal removal, the optimal dosage of sulfide ions was evaluated. For 33 mg/L of S=, the removal efficiency of Ni2+ is approximately 90%. The resulting sludge has been characterized by X-ray diffractometry, scanning electron microscopy, infrared spectroscopy and thermal analysis. It consists essentially of millerite and nickel oxide.

Perception of Corporate Social Responsibility by the Employees

2015 ◽  
pp. 51-72
Author(s):  
Zlatko Nedelko ◽  
Vojko Potocan
Keyword(s):  
Corporate Social Responsibility ◽  
Social Responsibility ◽  
Social Issues ◽  
The State ◽  
Economic Outcomes ◽  
Empirical Survey ◽  
Starting Point ◽  
Corporate Social ◽  
The Impact ◽  
Insight Into

The main purpose of this chapter is to examine the relationships between three underlying aspects of Corporate Social Responsibility (CSR), namely economic, environmental, and societal aspects, and the level of CSR, as perceived by the employees. The strength and direction of the impact of a single underlying aspect of CSR, on the level of CSR in organizations, is examined through a sample of 288 employees in Slovenian organizations. Results from the empirical survey suggest that employees' higher concern for environmental and social issues increases the level of organizational CSR, while higher striving for solely economic outcomes lowers the level of organizational CSR. Findings in this chapter provide insight into the state of CSR in organizations as perceived by the employees, providing an important starting point for definition or re-thinking of strategies in relation to CSR, and as a starting point for other actions as well, like changes in academia.

scholarly journals Boundary element modeling and analysis of adhesive bonded structural joints

2007 ◽  
Vol 4 (1) ◽  
Author(s):  
G. Cavallini ◽  
G. Davi ◽  
A. Milazzo
Keyword(s):  
Boundary Element ◽  
Anisotropic Elasticity ◽  
Stress And Strain ◽  
Bonded Joints ◽  
Strain Fields ◽  
Modeling And Analysis ◽  
Structural Joints ◽  
Element Technique ◽  
Good Agreement

In this paper, a boundary element technique for modeling and analysis of adhesive bonded structural joints is presented. The formulation is developed in the framework of the anisotropic elasticity and attention is focused on the application to composite structural joints built with the splicing concept technique. To model and analyze composite bonded joints a multidomain implementation of the boundary element method has been used. It has been proven well suited and very effective for the characterization of the mechanical behavior of spliced joints, allowing the analysis of the high gradient stress and strain fields near the splice lines as well as the prediction of the overall distribution of the interlaminar tractions. Numerical results show good agreement with analytical solution and finite element analyses.

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