Opening of an interface flaw in a layered elastic half-plane under compressive loading

A static analysis is given of the problem of an elastic layer perfectly bonded, except for a frictionless interface crack, to a dissimilar elastic half-plane. The free surface of the layer is loaded by a finite pressure distribution directly over the crack. The problem is formulated using the two dimensional linear elasticity equations. Using Fourier transforms, the governing equations are converted to a pair of coupled singular integral equations. The integral equations are reduced to a set of simultaneous algebraic equations by expanding the unknown functions in a series of Jacobi polynomials and then evaluating the singular Cauchy-type integrals. The resulting equations are found to be ill-conditioned and, consequently, are solved in the least-squares sense. Results from the analysis show that, under a normal pressure distribution on the free surface of the layer and depending on the combination of geometric and material parameters, the ends of the crack can open. The resulting stresses at the crack-tips are singular, implying that crack growth is possible. The extent of the opening and the crack-top stress intensity factors depend on the width of the pressure distribution zone, the layer thickness, and the relative material properties of the layer and half-plane

Optimized Integration of Renewable Energies into Existing Power Plant Portfolios

AbstractFossil fuel importing as well as exporting countries of the MENA region have recognized their enormous potential of power generation by renewable energy (RE) technologies and the associated benefit for their national budgets, and therefore have formulated ambitious targets for RE deployment. However, only few countries have a detailed master plan that shows how RE technologies can be integrated efficiently into their existing power plant portfolio. Capacity expansion of RE and conventional technologies must be adjusted and optimized in order to minimize total generation costs of the entire system while maintaining security of supply. Within the last three years, DLR has developed the capacity expansion and unit commitment optimization model REMix-CEM (Renewable Energy Mix – Capacity Expansion Model) in order to support authorities of the MENA region in the process of integrating RE technologies efficiently in the short-term and transforming their strongly growing fossil-fuel dominated power systems of today towards higher RE shares. REMix-CEM optimizes the capacity expansion of conventional and RE technologies from a state-owned utility perspective starting from the existing power plant portfolio by modeling the hourly performance of each single existing and candidate unit. The paper presents an overview of the developed methodology as well as the characteristics and capabilities of REMix-CEM by presenting a case study for the electricity sector of the Hashemite Kingdom of Jordan for the years 2013 – 2020

The British empire and the American Atlantic on Tristan da Cunha, 1811-16

The first permanent settlement on Tristan da Cunha was established in 1811 by the American Jonathan Lambert. News of Lambert's claim, which followed ceremonies of possession recognised by both British and American observers, spread throughout the Atlantic. Doubts soon emerged, however, as to Lambert's nationality and as to whether he claimed the island for himself, for the United States or for Britain. This article considers Lambert's settlement, the promulgation of his claim and the re-casting of both Lambert and his claim as British, an act which implicitly recognised the strength of Lambert's claim while appropriating that claim for imperial ends. Because Britons and Americans claimed sovereignty and ownership in the Atlantic in similar ways, the competition between British and American claims to Tristan sheds light on those ways' common British roots.link_to_subscribed_fulltex

Tapered Roller Bearing Damage Detection Using Decision Fusion Analysis

A diagnostic tool was developed for detecting fatigue damage of tapered roller bearings. Tapered roller bearings are used in helicopter transmissions and have potential for use in high bypass advanced gas turbine aircraft engines. A diagnostic tool was developed and evaluated experimentally by collecting oil debris data from failure progression tests conducted using health monitoring hardware. Failure progression tests were performed with tapered roller bearings under simulated engine load conditions. Tests were performed on one healthy bearing and three pre-damaged bearings. During each test, data from an on-line, in-line, inductance type oil debris sensor and three accelerometers were monitored and recorded for the occurrence of bearing failure. The bearing was removed and inspected periodically for damage progression throughout testing. Using data fusion techniques, two different monitoring technologies, oil debris analysis and vibration, were integrated into a health monitoring system for detecting bearing surface fatigue pitting damage. The data fusion diagnostic tool was evaluated during bearing failure progression tests under simulated engine load conditions. This integrated system showed improved detection of fatigue damage and health assessment of the tapered roller bearings as compared to using individual health monitoring technologies

Investigation of Tapered Roller Bearing Damage Detection Using Oil Debris Analysis

A diagnostic tool was developed for detecting fatigue damage to tapered roller bearings. Tapered roller bearings are used in helicopter transmissions and have potential for use in high bypass advanced gas turbine aircraft engines. This diagnostic tool was developed and evaluated experimentally by collecting oil debris data from failure progression tests performed by The Timken Company in their Tapered Roller Bearing Health Monitoring Test Rig. Failure progression tests were performed under simulated engine load conditions. Tests were performed on one healthy bearing and three predamaged bearings. During each test, data from an on-line, in-line, inductance type oil debris sensor was monitored and recorded for the occurrence of debris generated during failure of the bearing. The bearing was removed periodically for inspection throughout the failure progression tests. Results indicate the accumulated oil debris mass is a good predictor of damage on tapered roller bearings. The use of a fuzzy logic model to enable an easily interpreted diagnostic metric was proposed and demonstrated

Mortality risk and mental disorders: longitudinal results from the Upper Bavarian Study

The object of the study was the assessment of the mortality risk for persons with a mental disorder in an unselected representative community sample assessed longitudinally. Subjects from a rural area in Upper Bavaria (Germany) participated in semi-structured interviews conducted by research physicians in the 1970s (first assessment) and death-certificate diagnoses were obtained after an interval up to 13 years later. The sample consisted of 1668 community residents aged 15 years and over. Cox regression estimates resulted in an odds ratio of 1·35 (confidence interval 1·01 to 1·81) for persons with a mental disorder classified as marked to very severe. The odds ratio increased with increasing severity of mental illness from 1·04 for mild disorders, 1·30 for marked disorders, to 1·64 for severe or very severe disorders. The relative risk (odds ratio) for persons with a mental disorder only and no somatic disorder was 1·22, for persons with only a somatic disorder 2·00, and for those with both a mental and a somatic disorder 2·13. The presence of somatic illness was responsible for most of the excess mortality. Somatic disorders associated with excess mortality in mental disorders were diseases of the nervous system or sensory organs, diseases of the circulatory system, diseases of the gastrointestinal tract, and diseases of the skeleton, muscles and connective tissue (ICD-8). Thus, while mental illness alone had a limited effect on excess mortality, comorbidity with certain somatic disorders had a significant effec

Unraveling the In Vivo Protein Corona

Understanding the behavior of nanoparticles upon contact with a physiological environment is of urgent need in order to improve their properties for a successful therapeutic application. Most commonly, the interaction of nanoparticles with plasma proteins are studied under in vitro conditions. However, this has been shown to not reflect the complex situation after in vivo administration. Therefore, here we focused on the investigation of magnetic nanoparticles with blood proteins under in vivo conditions. Importantly, we observed a radically different proteome in vivo in comparison to the in vitro situation underlining the significance of in vivo protein corona studies. Next to this, we found that the in vivo corona profile does not significantly change over time. To mimic the in vivo situation, we established an approach, which we termed “ex vivo” as it uses whole blood freshly prepared from an animal. Overall, we present a comprehensive analysis focusing on the interaction between nanoparticles and blood proteins under in vivo conditions and how to mimic this situation with our ex vivo approach. This knowledge is needed to characterize the true biological identity of nanoparticles

Multicomponent encapsulation into fully degradable protein nanocarriers via interfacial azide-alkyne click reaction in miniemulsion allows the co-delivery of immunotherapeutics

Encapsulation of multiple adjuvants along with antigens into nanocarriers allows a co-delivery to antigen-presenting cells for the synergistic induction of robust immune responses. However, loading cargoes of different molar masses, polarities, and solubilities in high efficiencies remains a challenge. Therefore, we developed a strategy to encapsulate a triple combination of the so-called adjuvants, i.e. with Resiquimod (R848), muramyl dipeptide (MDP) and polyinosinic-polycytidylic acid (Poly(I : C)) into human serum albumin (HSA) nanocarriers. The loading is conducted in situ while the nanocarrier is formed by an orthogonal and metal-free click reaction at the interface of an inverse miniemulsion. By this unique approach, high encapsulation efficiency without harming the cargo during the nanocarrier formation process and regardless of their physical properties is achieved, thus keeping their bioactivity. Furthermore, we demonstrated high control over the encapsulation efficiency and varying the amount of each cargo did not influence the efficiency of multicomponent encapsulation. Azide-modified HSA was crosslinked with hexanediol dipropiolate (HDDP) at the interface of a water-in-oil miniemulsion. Varying the crosslinker amount allowed us to tailor the density and degradation rates of the protein shell. Additional installation of disulfide bonds into the crosslinker created redox-responsive nanocarriers, which degraded both by protease and under reducing conditions with dithiothreitol. The prepared HSA nanocarriers were efficiently taken up by dendritic cells and exhibited an additive cell activation and maturation, exceeding the nanocarriers loaded with only a single drug. This general protocol allows the orthogonal and metal-free encapsulation of various drugs or adjuvants at defined concentrations into the protein nanocarriers

Learning from Sustainability-Oriented Innovation

This chapter argues that insights from the realm of sustainability-oriented innovation can provide useful answers to the question of why Small and Medium-Sized Enterprises (SMEs) would (or should) become interested in implementing responsible innovation practices. It is based on the assumption that “responsible innovation” and “sustainability-oriented innovation” are different approaches aimed at orienting innovation towards increased positive impacts on social and natural environments. Motivations and influences for pursuing sustainability-oriented inno-vation have been studied in the past, and can provide insights into reasons for pursu-ing the implementation of responsible innovation practices