Assessment of foam fracture in sandwich beams using thermoelastic stress analysis

Thermoelastic Stress Analysis (TSA) has been well established for determining crack-tip parameters in metallic materials. This paper examines its ability to determine accurately the crack-tip parameters for PVC foam used in sandwich structures

Protein kinases in hormonal regulation of adipocyte metabolism.

Abstract Along with liver and muscle tissue, adipose tissue helps maintain normal levels of glucose and lipids in the blood and has a very important role when it comes to storing lipids that can provide whole-body energy. After a meal is ingested, adipocytes take up glucose from the circulation and use it as a substrate for synthesis of new fatty acids (FAs) in a process known as de novo fatty acid synthesis, as well as for synthesis of glycerol. Adipocytes also take up fatty acids from the circulation and incorporate both newly synthesized and imported FAs into triacylglycerides (TAGs), in a process known as lipogenesis. TAGs are stored in large lipid droplets in the cytosol, and during fasting, or in response to physical exercise, they are hydrolysed in a process known as lipolysis, in which FAs are released into the bloodstream for use as energy substrates in other tissues. These cycles of lipogenesis and lipolysis are controlled by the concerted actions of insulin, a hormone that is secreted by the pancreas and catecholamines, hormones that are secreted by the adrenal glands, or derive from the nervous system. Both glucose- and fatty acid uptake, as well as lipid storage and mobilization, are regulated by cellular signaling, and kinases are central enzymatic players in hormone-induced cellular signaling. A dysfunctional adipose tissue can contribute to insulin resistance in many obese individuals. Therefore it is important to elucidate the cellular mechanisms that govern metabolic processes in adipocytes. Insulin is the hormone that promotes glucose uptake and lipogenesis in adipocytes, and when it induces glucose uptake, insulin exerts it actions through protein kinase B (PKB). Although PKB is known to mediate many effects of insulin, its role in lipogenesis in adipocytes is less clear. We show that PKB is important for the effects of insulin on lipogenesis (de novo and total). We also reveal that PKB can regulate Amp-activated protein kinase (AMPK) in adipocytes by a mechanism previously only seen in heart muscle cells. AMPK is a sensor of cellular energy status and known to inhibit lipogenesis. We speculate that insulin possibly mediates its lipogenic effects via a decrease in AMPK activity accomplished by PKB-phosphorylation of S485 on AMPK. Furthermore, we find that salt-inducible kinase 3 (SIK3), a kinase that belongs to the AMPK-related family of kinases, and displays structural similarities to AMPK, can be regulated by catecholamines in adipocytes. Catecholamines are hormones that bind to β-adrenergic receptors and act by increasing cellular levels of cAMP, which in turn activates protein kinase A (PKA). We find that in response to such β-adrenergic stimuli, SIK3 is phosphorylated on multiple serine and threonine residues. This 10 regulation coincides with an increase in binding of SIK3 to 14-3-3 molecules. 14-3-3 proteins are cellular scaffolding proteins that can result in cellular re-localization of their binding partners or in their binding to other proteins or lipids. We find that when SIK3 is phosphorylated in response to β-adrenergic stimuli, the kinase does not re-localize, but is partially de-activated. We speculate that SIK3 could potentially have a role in adipocyte metabolism, as it is regulated by catecholamines in this tissue. Finally, we address the current understanding of the role for AMPK in modulation of the effects of insulin and catecholamines on glucose uptake and lipid metabolism. To this date, it has been suggested that AMPK reduces insulin-induced glucose uptake and lipogenesis, as well as inhibits catecholamine-induced lipolysis in adipocytes. These findings are mainly based on studies performed with AMPK activating agents that act on AMPK in an indirect manner. We have used the allosteric activator A769662, that binds directly to AMPK, and find that AMPK does not appear to modulate hormonally induced glucose uptake, lipolysis or total lipogenesis. However, when we specifically measured the synthesis of new FAs, using acetate as a lipogenic substrate (as opposed to using glucose as a substrate, a molecule which can participate in both FA and glycerol synthesis), we observe that AMPK does indeed reduce insulin-induced de novo fatty acid synthesis. Collectively, we add novel findings to the available knowledge on key kinases and cellular signaling in adipocyte metabolism. Our findings contribute to the understanding of insulin- and catecholamine-mediated control of lipid storage in adipose tissue, a biological function that, when dysfunctional, is strongly linked to insulin resistance and type 2 diabetes (T2D)

State of the Art Review of High Voltage Insulation Monitoring

The devastating effects of global warming and climate change are now well understood and there is broad unity that fundamental changes are needed. This is clearly addressed in the United Nations Sustainable Development Goals. The main perpetrator contributing to global warming and climate change is how we consume energy, which will need to transition from fossil fuels to renewable energy. The mass integration of renewable energy sources aimed to mitigate the effects of global warming, will greatly alter how we generate, transmit and consume energy. If we combine this with the large shift in load consumption, due to the integration of electrical vehicles, there is no doubt that the electrical transmission system will be subjected to major changes in future decades. The existing transmission grid is an aged and mature system, with large parts being installed all the way back in 60s and 70s, thus nearing the end of service. The existing grid has continuous performance issues and the knowledge on fault and ageing mechanisms are still insufficient. A thorough assessment of the current state of the grid is necessary in order to properly gauge its ability to cope with mass integration of HV systems, predominantly HVDC. A key part in assessing the current state of the grid while simultaneously increase its resilience is the utilization of high voltage monitoring methods, as they are key to prevent and predict transmission faults. Due to the increased requirement of long distance high capacity transmission, especially in submarine conditions, the knowledge and monitoring of cables will be of high importance. Compared to AC technology, DC have been regarded as niche and specialist field, thus have been allocated far less attention and research, hence the knowledge and technology of DC is still limited. This thesis will assess the state of the art of high voltage monitoring while simultaneously explore its role towards achieving the UN Sustainable Development Goals. Keywords: UN Sustainability Goals, Partial Discharges, Tan Delta, SF6, XLPE, High Voltage MonitoringMasteroppgave i energiENERGI399MAMN-ENER

Nationale Identitäten und ein gemeinschaftlicher Bildungsanspruch der EU - ein unauflöslicher Widerspruch?

[The] article raises the question whether there is a contradiction for the formal education between national identities and a common European objective for education. This could be the case because the different educational systems are the result of old national traditions and the expression of national identities. The article gives an overview over the development of a European educational policy to clarify this tension between education and European identities. (DIPF/Orig.

Effect of Initial Debond Crack Location on the Face/core Debond Fracture Toughness

This paper studies the effect of initial crack location on the face/core debond fracture toughness under different mixed mode loading conditions. The mixed mode loading at the crack tip is defined in terms of the mode-mixity. In order to achieve the desired initial debond crack location, a pre-cracking technique is developed, where the mode-mixity, number of cycles, crack increment and load level are accurately controlled. Results show that the debond fracture resistance of foam-cored sandwich specimens depends on parameters such as loading condition (mode-mixity), core and face properties, as well as initial debond crack location. Lower fracture toughness values were measured for specimens with the initial crack location in the face laminate

Locating Chinatown in the global village: Cultural innovation in Taiwan\u27s multichannel environment

The availability of media technology in the mid-1980s in Taiwan has forever changed the landscape of its television industry. With the help of cable and satellite technologies, audiences in Taiwan today receive an average of 60 channels, 20 times the number available just a few years ago. Through focus group interviews, this study examines the possible cultural implications of such speedy changes for a society that is in the midst of political, cultural, social and economic transitions. The results indicate that Chinese cultural identity in Taiwan has come to another crossroad and stress the prospect of cultural innovation as a possible outcome in the age of a multichannel environment. The study also advocates further thoughtful consideration over potential media impacts on culture as the world strips itself of distinguishing characteristics on the path toward the global village