STRESS MEASUREMENTS AT HOT SPOTS USING STRESSPROBE

ABSTRACT The estimation stress concentration factor (SCF) of weld details of floating structures is critical parameter for fatigue life predictions. The common practice for predicting the SCF value is the use of code-specified empirical equations and through detailed finite element analysis (FEA) for critical joints. Under certain conditions, it becomes necessary to reassess the SCF value while the structure is in service. The most accurate approach is to measure the SCF value on the real joint since variations in FEA results always exist due to variation on modeling techniques by different analysts. While the use of strain gauges is the standard approach, applying strain gauges in service can be extremely complicated. Therefore, an alternative approach for direct measurement that does not require removal of coating and bonding to the surface is attractive. The StressProbe that takes advantage of the change in the magnetic permeability of steel due to the presence of a mechanical stress offers the required alternative as a non-contacting strain measurement method. The paper presents the results of a study to assess that capability of the StressProbe in measuring SCF value by measuring variations in strain in a high strain gradient region of a hopper corner detail that is typical in floating structures and compare the results with those obtained using both strain gauges and finite element analysis. The results show that the StressProbe can be used for the determination of the SCF at a weld under various scenarios and it can also be used to monitor cyclic stresses during periods when there is wave loading. While there is some variability in the StressProbe results but given the variability found with strain gauges it is considered that the StressProbe could be used to replace strain gauges

Innovation Management Techniques and Tools: a review from Theory and Practice

Knowledge is considered to be an economic driver in today’s economy. It has become a commodity, a resource that can be packed and transferred. The objective of this paper is to provide a comprehensive review of the scope, trends and major actors (firms, organizations, government, consultants, academia, etc.) in the development and use of methods to manage innovation in a knowledge-driven economy. The paper identifies the main innovation management techniques (IMTs) aiming at the improvement of firm competitiveness by means of knowledge management. It will specifically focus on those IMTs for which knowledge is a relevant part of the innovation process. The research study, based on a survey at the European level, concludes that a knowledge-driven economy affects the innovation process and approach. The traditional idea that innovation is based on research (technology-push theory) and interaction between firms and other actors has been replaced by the current social network theory of innovation, where knowledge plays a crucial role in fostering innovation. Simultaneously, organizations in both public and private sectors have launched initiatives to develop methodologies and tools to support business innovation management. Higher education establishments, business schools and consulting companies are developing innovative and adequate methodologies and tools, while public authorities are designing and setting up education and training schemes aimed at disseminating best practices among all kinds of businesse

DNA methylation and body mass index from birth to adolescence : meta-analyses of epigenome-wide association studies

Background DNA methylation has been shown to be associated with adiposity in adulthood. However, whether similar DNA methylation patterns are associated with childhood and adolescent body mass index (BMI) is largely unknown. More insight into this relationship at younger ages may have implications for future prevention of obesity and its related traits. Methods We examined whether DNA methylation in cord blood and whole blood in childhood and adolescence was associated with BMI in the age range from 2 to 18 years using both cross-sectional and longitudinal models. We performed meta-analyses of epigenome-wide association studies including up to 4133 children from 23 studies. We examined the overlap of findings reported in previous studies in children and adults with those in our analyses and calculated enrichment. Results DNA methylation at three CpGs (cg05937453, cg25212453, and cg10040131), each in a different age range, was associated with BMI at Bonferroni significance, P <1.06 x 10(-7), with a 0.96 standard deviation score (SDS) (standard error (SE) 0.17), 0.32 SDS (SE 0.06), and 0.32 BMI SDS (SE 0.06) higher BMI per 10% increase in methylation, respectively. DNA methylation at nine additional CpGs in the cross-sectional childhood model was associated with BMI at false discovery rate significance. The strength of the associations of DNA methylation at the 187 CpGs previously identified to be associated with adult BMI, increased with advancing age across childhood and adolescence in our analyses. In addition, correlation coefficients between effect estimates for those CpGs in adults and in children and adolescents also increased. Among the top findings for each age range, we observed increasing enrichment for the CpGs that were previously identified in adults (birth P-enrichment = 1; childhood P-enrichment = 2.00 x 10(-4); adolescence P-enrichment = 2.10 x 10(-7)). Conclusions There were only minimal associations of DNA methylation with childhood and adolescent BMI. With the advancing age of the participants across childhood and adolescence, we observed increasing overlap with altered DNA methylation loci reported in association with adult BMI. These findings may be compatible with the hypothesis that DNA methylation differences are mostly a consequence rather than a cause of obesity.Peer reviewe

Troublesome trade-offs: balancing urban activities and values when securing a city-centre governmental quarter

Background Homeland security measures increasingly affect urban life and activities. Standoff distance, which prevents unscreened vehicles from approaching within a certain distance of a building, is a widely applied measure when protecting buildings against attacks with vehicle-borne improvised explosive devices. This measure both is rather inexpensive and has few negative externalities when implemented in rural areas. Unfortunately, sites with protection needs often are situated in city centres. Methods We apply the so-called Security Function Framework to illuminate the externalities or the ‘troublesome trade-offs’ between protecting a high-value site against vehicle-borne improvised explosive devices and protecting other urban values. Results This paper demonstrates that standoff creates challenges for other important values, such as functional office spaces for all employees, deliveries and emergency vehicle access. Simultaneously, standoff creates opportunities for reinforcing social-responsibility requirements, such as accessibility for pedestrians and environmental considerations. Conclusions Security measures can have both negative and positive externalities and planning might alleviate some of the negative ones

Attractor crisis and bursting in a fluid flow with two no-slip directions

Characteristic burtsing behavior is observed in a driven, two-dimensional viscous flow, confined to a square domain and subject to no-slip boundaries. Passing a critical parameter value, an existing chaotic attractor undergoes a crisis, after which the flow initially enters a transient bursting regime. Bursting is caused by ejections from and return to a limited subdomain of the phase space, whereas the precrisis chaotic set forms the asymptotic attractor of the flow. For increasing values of the control parameter the length of the bursting regime increases progressively. Passing another critical parameter value, a second crisis leads to the appearance of a secondary type of bursting, of very large dynamical range. Within the bursting regime the flow then switches in irregular intervals from the primary to the secondary type of bursting. Peak enstrophy levels for both types of bursting are associated to the collapse of a primary vortex into a quadrupolar state

SCALAR POLITICS AND NETWORK RELATIONS IN THE GOVERNANCE OF HIGHLY SKILLED MIGRATION

Recently, migration scholars have started to examine the roles of nonstate actors in migration governance. This is also the case in highly skilled migration, as they try to shape local and national migration policies to attract and retain global talent. This article brings together literatures on scalar politics and policy networks to investigate the roles of nonstate actors in highly skilled migration governance in Norway’s petroleum industry. The article makes three arguments. First, national state actors have clearly delineated the spheres of influence in highly skilled migration policymaking. These boundary-setting practices ensure that the state remains in charge of key domains related to international migration and employment. Second, place shapes the (re)scaling and networking practices of public and nonstate actors. Third, new, nonstate actors have emerged that transcend scalar hierarchies through public-private partnerships. The most influential state actors, however, refrain from these alliances to remain neutral in politically charged issues.United States National Science Foundation (1155339