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This paper presents the defects that occur during the assembly and manufacturing of solder joints in single‐sided insertion‐mount printed wiring boards (PWBs). Each type of defect is discussed, with particular focus on how these defects are related to solderability issues, the mechanisms of failure due to defect‐induced failure accelerators, and the effect of the defect on solder joint reliability.

OWING to the comparatively early date in the year of the Library Association Conference, this number of THE LIBRARY WORLD is published so that it may be in the hands of our readers before it begins. The official programme is not in the hands of members at the time we write, but the circumstances are such this year that delay has been inevitable. We have dwelt already on the good fortune we enjoy in going to the beautiful West‐Country Spa. At this time of year it is at its best, and, if the weather is more genial than this weather‐chequered year gives us reason to expect, the Conference should be memorable on that account alone. The Conference has always been the focus of library friendships, and this idea, now that the Association is so large, should be developed. To be a member is to be one of a freemasonry of librarians, pledged to help and forward the work of one another. It is not in the conference rooms alone, where we listen, not always completely awake, to papers not always eloquent or cleverly read, that we gain most, although no one would discount these; it is in the hotels and boarding houses and restaurants, over dinner tables and in the easy chairs of the lounges, that we draw out really useful business information. In short, shop is the subject‐matter of conference conversation, and only misanthropic curmudgeons think otherwise.

The purpose of this paper is to discuss the capability of nonlinear frequency domain (NLFD) method in predicting surface pressure coefficient presented in the time domain in unsteady transonic flows.

In this research, the solution and spatial operator are approximated by discrete form of Fourier transformation and resulting nonlinear equations are solved by use of pseudo‐spectral approach. Considered transonic flows involve different flow pattern on the airfoil surfaces. One of the test cases involves moving shocks on both lower and upper airfoil surfaces and in the two other test cases a moving shock occurs only on the upper surface.

Pressure distributions presented in the time domain using NLFD are compared with three test cases. Results show that NLFD predicts reasonable pressure distributions in time domain except in vicinity of shock positions. Although this method may predict unfair results near shock positions, however gives good estimates for global properties such as lift coefficient.

In the previous works on NLFD method, the flow field results have been limited to representing the pressure in the frequency domain or global coefficients such as lift coefficients. No details of pressure distributions in the time domain have been provided in such investigations. In this research, by presenting the pressure in the time domain, the conditions on which good pressure distributions are obtained are demonstrated.

The purpose of this paper is to propose an alternative test board design with only one loading condition and sufficiently large sample size, which is more suitable for the statistical package qualification. With the exception of the board shape and size and package component layout, all other aspects of the design strictly follow the JEDEC standard so that the board design can be easily implemented.

A test board in a round shape was introduced. First, drop tests were carried out. Then, the dye stain test and metallurgical analysis were performed in order to study the failure mechanism of lead‐free solder joint under drop impact.

The test results indicate that the combined effect of mechanical shock and PCB bending vibration is the root cause of solder joint failure under drop impact, and that the maximum peeling stress of the critical solder joint could be considered to be the dominant failure factor. On the other hand, the fracture of BGA lead‐free solder joints occurs at intermetallic compound (IMC) interface near the package side, and failure mode is brittle fracture.

These results are the same as those of JEDEC standard test board. Furthermore, the solder joint loading conditions in this design are simplified from six to one. The round test board can take the place of JEDEC standard test board to carry out drop test and to enable good solder joint life prediction and statistical analysis.

The purpose of the article is to introduce the outcomes of a study analyzing the relationships between willingness to use technology for health purposes, health information behavior (HIB), health behavior (HB) choices, readiness for COVID-19 vaccination, socioeconomic indicators and self-reported health among older adults aged = 50 years living in Estonia.

A cross-sectional survey was conducted among 501 people aged = 50 in Estonia in 2020, a month after the end of lockdown.

The results of the study indicate that the more recurrent the need for HI was (rho = 0.11, p < 0.05) and the more regularly one searched for it (rho = 0.14, p < 0.01), the more willing a person was to get vaccinated. Also, interest in digital applications corresponded to vaccination readiness (rho = 0.25, p < 0.001). However, this relationship did not emerge in the case of other HBs such as healthy eating and exercise. Differences in HIB should be taken into account when developing effective means of health communication designed especially for crisis situations.

Estonia is known as one of the digital front runners in the world. However, social welfare and the well-being of disadvantaged groups among the population (e.g. older people) have not yet caught up with the more developed Western countries. Thus, learning more about the health-related information behavior of older adults, e.g. the kind of health information they are seeking and using in Estonia, allows policymakers, health information providers and libraries in Estonia to plan and carry out more effective interventions and help them to improve the existing systems so as to furnish older adults with relevant information.

The purpose of the Building Everyday Life programme is to improve parenting outcomes through better sharing of family responsibilities and to encourage a strong sense of solidarity and community.

Data have been obtained from the pre-test and post-test applications, respectively, using two instruments: the Inventory of Parenting and Family Life Patterns and Resources, and the Final Evaluation Questionnaire for parents. The authors also use these tools to evaluate the degree to which the changes are maintained six months after the completion of the programme. Participants in the study comprised a group of 35 individuals that included parents in nuclear families and single mothers. The assessment process involved three stages: a pre-test assessment, a qualitative report (summative assessment) and, finally, a post-test assessment at least six months after completion of the programme.

The results show lasting changes over time. Regarding domestic work, parents say that they are more aware of the need to achieve a fairer and more equal distribution of the tasks in question. Families also report that they have perceived changes in the dimensions of communication and conflict resolution. Bearing in mind the limited nature of the aforementioned changes, the results suggest the need for support processes over time, as well as the establishment of follow-up sessions with families.

The main contribution of the study is to show that the Building Everyday Life programme is effective and valuable in improving parental educational styles.

Educated elites are making their mark on the stratification structure of the metropolitan US. Educated elites are proportionally greater whenever the economy is service dominated, and furthermore, these elites are the key factor in explaining why disparities resulting from high earners are present in service dominated areas. The resulting inequality in earnings is one of the unanticipated consequences of the growth of an educated elite, at least among males. It remains to be seen whether female elites will resemble males in their influence on inequality if sex differences in earnings disappear. The elite is a professional cadre rather than an aristocracy based solely on inherited wealth, placed just beyond an upper middle class. Given their background, education, affluence and numbers, the choices this elite makes on issues will influence the course of society.

Research has consistently shown that the children of business owners are more likely to become business owners themselves. However, what mechanism(s) underlies this intergenerational correlation is still not clear. In this research I assess the importance of several mechanisms proposed to drive the children of business owners to expect to become business owners.

Quantitative analyses of representative data from the 1988 to 1992 National Education Longitudinal Study are employed.

Results are inconsistent with arguments asserting that the children of business owners expect to become business owners because of: the transmission of human capital or financial capital; the expectation of inheriting a business; a heightened awareness of the viability of business ownership; or preferences for having lots of money, leisure time, being successful in work, or steady employment. Findings are consistent with the notion that the intergenerational correlation in business ownership is a result of shared preferences and/or traits, and this effect is particularly strong when accompanied by awareness of paternal business ownership.

Identifying which mechanism underlies the intergenerational transmission may inform how to increase rates of business ownership, particularly among underrepresented groups, which is a matter of increasing policy interest. However, our understanding is limited because: the intergenerational transfer is consistent with numerous mechanisms; and employment outcomes are often used to make inferences about preceding processes. This chapter focuses on expectations that precede outcomes to clarify which mechanism operates in one stage of the transmission process.