Mechanics of Fracture in Adhesive Joints

Interdependence of continuum mechanics and physical chemistry in failure analysis of adhesive

Fracture Mechanics of Joints

Almost every engineering design requires that component members be connected. A disadvantage of mechanical connections such as bolts, screws or rivets is that they do not uniformly distribute the load; hence large local stresses result. This problem can often be reduced ~ joining the members adhesively. Major problems with adhesives that have tended to limit their wider us age include: (1) how the strength of an adhesive and the joint in which it is used can reliably be predicted, and (2) what factors tend to limit the strength of an adhesive joint and how they might be eliminated . It is the intent of the authors to show how fracture mechanics might be used to develop a rational philosophy and methodology that will aid in overcoming these problems

Creation of Skyrmions in a Spinor Bose-Einstein Condensate

We propose a scheme for the creation of skyrmions (coreless vortices) in a Bose-Einstein condensate with hyperfine spin F=1. In this scheme, four traveling-wave laser beams, with Gaussian or Laguerre-Gaussian transverse profiles, induce Raman transitions with an anomalous dependence on the laser polarization, thereby generating the optical potential required for producing skyrmions.Comment: 5 pages, 2 figures, RevTe

Violence against children perpetrated by peers: A cross-sectional school-based survey in Uganda

Violence against children by peers is a global public health problem. We aimed to assess factors associated with peer violence victimization among primary school children in Uganda. We conducted multilevel multivariable logistic regression analyses of cross-sectional data from 3706 primary students in 42 Ugandan primary schools. Among primary school students, 29% and 34% had ever experienced physical and emotional violence perpetrated by their peers, respectively. Factors strongly associated with both physical and emotional violence were similar and overlapping, and included exposure to interparental violence, having an attitude supportive of violence against children from school staff, not living with biological parents, working for payment, and higher SDQ score. However, we found that younger age, sharing sleeping area with an adult and achieving a higher educational performance score, were specifically associated with physical violence. On the other hand, being female, walking to school, reporting disability and eating one meal on the previous day, were particularly associated with emotional violence. Interventions to reduce peer violence should focus on family contexts, school environments and those with poor socio-economic status may need extra support

Exploring Couples' Processes of Change in the Context of SASA!, a Violence Against Women and HIV Prevention Intervention in Uganda.

There is now a growing body of research indicating that prevention interventions can reduce intimate partner violence (IPV); much less is known, however, about how couples exposed to these interventions experience the change process, particularly in low-income countries. Understanding the dynamic process that brings about the cessation of IPV is essential for understanding how interventions work (or don't) to reduce IPV. This study aimed to provide a better understanding of how couples' involvement with SASA!-a violence against women and HIV-related community mobilisation intervention developed by Raising Voices in Uganda-influenced processes of change in relationships. Qualitative data were collected from each partner in separate in-depth interviews following the intervention. Dyadic analysis was conducted using framework analysis methods. Study findings suggest that engagement with SASA! contributed to varied experiences and degrees of change at the individual and relationship levels. Reflection around healthy relationships and communication skills learned through SASA! activities or community activists led to more positive interaction among many couples, which reduced conflict and IPV. This nurtured a growing trust and respect between many partners, facilitating change in longstanding conflicts and generating greater intimacy and love as well as increased partnership among couples to manage economic challenges. This study draws attention to the value of researching and working with both women, men and couples to prevent IPV and suggests IPV prevention interventions may benefit from the inclusion of relationship skills building and support within the context of community mobilisation interventions

Intracranial oligodendroglioma with optic nerve infiltration in a Labrador retriever

A seven-year-old neutered male Labrador retriever was presented with behavioral changes and reduced vision. Neurological examination revealed blindness of the left eye with a positive pupillary light reflex and a decreased mental status. Blood and cerebrospinal fluid analyses showed no abnormalities. MRI revealed a deviant area located in the thalamic, hypothalamic and caudate nuclear regions. Invasion of the left optic nerve was also observed. The dog was euthanized after 38 days of palliative treatment. Necropsy showed a non-encapsulated extruding white lardaceous mass, with a diameter of 2 cm, in the white matter, located in the ventral thalamic region near the chiasma opticum, which extended along the left optic nerve. Histologically, neoplastic cells had a “fried egg” appearance. Immunolabelling for glial fibrillary acidic protein demonstrated the presence of numerous reactive astrocytes. The tumor was diagnosed as a low grade (II) intracranial oligodendroglioma with infiltration of the optic nerve.</jats:p

Nonlinear transport in nanoscale phase separated colossal magnetoresistive oxide thin films

We report a study of the I-V characteristics of 2.5–5.4 nm epitaxial La1xSrxMnO3 (x = 0.33 and 0.5) and La0.7Ca0.3MnO3 thin films. While La0.67Sr0.33MnO3 films exhibit linear conduction over the entire temperature and magnetic field ranges investigated, we observe a strong correlation between the linearity of the I-V relation and the metal-insulator transition in highly phase separated La0.5Sr0.5MnO3 and La0.7Ca0.3MnO3 films. Linear I-V behavior has been observed in the high temperature paramagnetic insulating phase, and an additional current term proportional to Va (a = 1.5–2.8) starts to develop below the metal-insulator transition temperature TMI, with the onset temperature of the nonlinearity increasing in magnetic field as TMI increases. The exponent a increases with decreasing temperature and increasing magnetic field and is significantly enhanced in ultrathin films with thicknesses close to that of the electrically dead layer. We attribute the origin of the nonlinearity to transport through the nanoscale coexisting metallic and insulating regions. Our results suggest that phase separation is not fully quenched even at low temperatures and high magnetic fields