A deflection, buckling and stress investigation into telescopic cantilever beams

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The telescoping cantilever beam structure is applied in many different engineering sectors to achieve weight/space optimisation for structural integrity. There has been limited theory and analysis in the public domain of the stresses and deflections involved when applying a load to such a structure. This thesis proposes (a) The Tip Reaction Model, which adapts classical mechanics to predict deflection of a two and a three section steel telescoping cantilever beam; (b) An equation to determine the Critical buckling loads for a given configuration of the two section steel telescoping cantilever beam assembly derived from first principles, in particular the energy methods; and finally (c) the derivation of a design optimization methodology, to tackle localised buckling induced by shear, torsion and a combination of both, in the individual, constituent, hollow rectangular beam sections of the telescopic assembly. Bending stress and shear stress is numerically calculated for the same structure whilst subjected to inline and offset loading. An FEA model of the structure is solved to verify the previous deflection, stress and buckling predictions made numerically. Finally an experimental setup is conducted where deflections and stresses are measured whilst a two section assembly is subjected to various loading and boundary conditions. The results between the predicted theory, FEA and experimental setup are compared and discussed. The overall conclusion is that there is good correlation between the three sets of data

Factor Influencing Gender Based Violence Among Pregnant Women Attending Antenatal Clinic in PHC of Syangja District, Nepal

Pregnancy and childbirth were a time of unique vulnerability to violence victimization because of changes in women’s physical, social, emotional, and economic needs during pregnancy. This study aims to determine the factors associated with gender-based violence among pregnant women attending antenatal care clinic (ANC). A cross-sectional study was conducted among 202 pregnant women attend antenatal ward of primary health care centre (PHC) of Syangja district during September 2014 to December 2014 by using semi-structure questionnaire with face to face interviews. SPSS software was used for analysis the data. The prevalence of gender based violence (GBV) among pregnant women was found to be 91.1%. The socio-demographic variables such as ethnicity, religious, the age of respondents, the age of marriage, occupation, and annual income had no association with the experience of different types of GBV (p>0.05). However, there was a statistically association between husband education (p=0.03), the age of marriage (p=0.039) and type of marriage (p=0.013) in case of psychological and economic violence whereas there was no statistically association between with other types of violence. In conclusion, gender based violence during pregnancy was a major prevalent public health problem is Syangja district of Nepal. Focus on age of marriage, types of marriage and education of husband may reduce gender based violence among the pregnant women. Women’s empowerment, economic autonomy, sensitization, awareness and needed of large-scale population-based surveys were the major recommendation of this study

Total Thiols and MDA Levels in Patients with Acute Myocardial Infarction Before and After Reperfusion Therapy

Background: Reactive oxygen species have been implicated in the pathogenesis of ischemic and reperfusion injury. In the current work we have measured malondialdehyde (MDA), total thiols, total CK, CK-MB and AST in ECG proven acute myocardial infarction (AMI) patients immediately after admission and 24 hours after administration of thrombolytic agent streptokinase, and in healthy controls. Methods: Blood samples from 44 AMI patients and 25 age and sex matched healthy controls were obtained and analyzed for MDA, total thiols using spectrophotometric methods and cardiac enzymes CK, CK-MB and AST using automated analyzer. Results: We have found significant increase in MDA, CPK, CK-MB, AST (p< 0.001) and significant decrease in total thiols (p<0.001) in AMI patients after thrombolytic therapy compared to values at admission, and healthy controls. MDA correlated negatively with total thiols (r = - 0.333, p<0.05) and positively with CK-MB (r = 0.491, p<0.01) in AMI patients after thrombolytic therapy. Conclusions: Reperfusion following thrombolytic therapy increases reactive oxygen species with concomitant decrease in antioxidant total thiols

Interplay of antiferromagnetism, ferromagnetism and superconductivity in EuFe_2(As_1-xP_x)_2 single crystals

We report a systematic study on the influence of antiferromagnetic and ferromagnetic phases of Eu^2+ moments on the superconducting phase upon doping the As site by isovalent P, which acts as chemical pressure on EuFe_2As_2. Bulk superconductivity with transition temperatures of 22 K and 28 K are observed for x=0.16 and 0.20 samples respectively. The Eu ions order antiferromagnetically for x=0.22 whereupon the Eu ions order ferromagnetically. Density functional theory based calculations reproduce the observed experimental findings consistently. We discuss in detail the coexistence of superconductivity and magnetism in a tiny region of the phase space and comment on the competition of ferromagnetism and superconductivity in the title compound.Comment: 6 pages, 5 figures, 1 tabl