Transient vibration of thin rectangular cantilever plates

When an elastic structure is subjected to a static load the deformation produced is independent of time and is a state of equilibrium between the applied load and the elastic properties of the system.Where dynamic loads are involved the state of equilibrium is no longer independent of time but includes the effects of the inertial forces due to the motion of the system. Only in certain cases does the deformation of the structure retain a particular shape while varying in magnitude. In general both the deflection at a given point and the shape of the deformation throughout the system are time-dependent.The eventual failure of a structural component may be due to metal fatigue, rather than the actual values of stresses associated with the dynamic loads since a vibration may continue to exist for some time after removal of the load.The present problem was suggest by the lace of its consideration in the literature, either theoretically or experimentally.Greenspon (1955) studied the deflections and stresses induced by transient loading in plates with simply supported or clamped edges, and obtained an approximate formula for the maximum deflection and stress. No experimental results were available but static deflections and stresses were compared with published results given by Timoshenko (1940) for some combinations of clamped and supported edges. Part of the analysis requires the calculation of natural frequencies of transverse vibration of she plate and Greenspon states that the method he employs can be used for plates with free, supported or clamped edges. The expression he uses is based on the differential equation of motion for the plate (see equation (35), Chapter 3) and requires the approximate deflection shape to satisfy the boundary conditions at the edges of the plate. The approximating functions used by Greenspon do satisfy the conditions for supported or clamped edges but not those for free edges. Frequencies calculated by this method for cases with free edges can be either higher or lower than the true frequencies. This is especially true for a cantilever Plate which has three free edges, the approximate frequency differing from the experimental value by a very wide margin.Chapter 2 of this dissertation is devoted to a discussion of methods suitable for calculating the natural frequencies of plates.In the analysis of vibration of a plate two of t e most important factors are the natural frequencies and modes of vibration of the plate. Approximate calculation of these quantities is described in Chapter 2.Chapter 3 contains the mathematical analysis of the transient vibration of a cantilever plate. produced by an arbitrary load distribution, and also considers the particular case of a concentrated force (as applied to the impact problem).Experimental and calculated results are given in Chapter 4. The final chapter summarises these results and discusses possible extensions which could be made in the analysis

Imaging correlates of molecular signatures in oligodendrogliomas.

Molecular subsets of oligodendroglioma behave in biologically distinct ways. Their locations in the brain, rates of growth, and responses to therapy differ with their genotypes. Retrospectively, we inquired whether allelic loss of chromosomal arms 1p and 19q, an early molecular event and favorable prognostic marker in oligodendrogliomas, were reflected in their appearance on magnetic resonance imaging. Loss of 1p and 19q was associated with an indistinct border on T(1) images and mixed intensity signal on T(1) and T(2). Loss of 1p and 19q was also associated with paramagnetic susceptibility effect and with calcification, a common histopathological finding in oligodendrogliomas. These data encourage prospective evaluation of molecular alterations and magnetic resonance imaging characteristics of glial neoplasms

Provision of NICE recommended Varicose Vein Treatment in the NHS

Background: Standardization of access to treatment and compliance with clinical guidelines are important to ensure the delivery ofhigh-quality care to people with varicose veins. In the National Health Service (NHS) in England, commissioning of care for people withvaricose veins is performed by Clinical Commissioning Groups (CCGs) and clinical guidelines have been developed by the NationalInstitute for Health and Care Excellence (NICE CG168). The Evidence-Based Intervention (EBI) programme was introduced in theNHS with the aim of improving care quality and supporting implementation of NICE CG168. The aim of this study was to assessaccess to varicose vein treatments in the NHS and the impact of EBI.Methods: CCG policies for the delivery of varicose vein treatments in the NHS in England were obtained from 2017 (before EBIintroduction) and 2019 (after EBI introduction) and categorized by two independent reviewers into levels of compliance with NICECG168. Hospital Episode Statistics data were compared with the NICE commissioning model predictions. A quality-adjusted life-yearwas valued at £20 000 (Euro 23 000 15 November 2022).Results: Despite the introduction of the EBI programme, CCG compliance with NICE CG168 fell from 34.0 per cent (64 of 191) to 29.0 per cent(55 of 191). Some 33.0 per cent of CCG policies (63 of 191) became less compliant and only 7.3 per cent (14 of 191) changed to become fullycompliant. Overall, 66.5 per cent of CCGs (127 of 191) provided less than the recommended intervention rate before EBI and this increasedto 73.3 per cent (140 of191) after EBI. The overall proportion of patients estimated to require treatment annually who received treatmentfell from 44.0 to 37.0 per cent. The associated estimated loss in net health benefit was between £164 and 174 million (Euro 188 million and199 million 15 November 2022) over 3 years. A compliant policy was associated with a higher intervention rate; however, commissioningpolicy was associated with only 16.8 per cent of the variation in intervention rate (R2=0.168, P<0.001).Conclusion: Many local varicose vein commissioning policies in the NHS are not compliant with NICE CG168. More than half of patientswho should be offered varicose vein treatment are not receiving it, and there is widespread geographical variation. The EBI programmehas not been associated with any improvement in commissioning or access to varicose vein treatment

8-Chloro-5-(4-phenethylpiperazin-1-­yl)pyrido[2,3-b][1,5]benzoxazepine

As part of an anti­psychotic drug discovery program, we report the crystal structure of the title compound, C24H23ClN4O. The mol­ecule has a tricyclic framework with a characteristic buckled V-shaped pyridobenzoxazepine unit, with the central seven-membered heterocycle in a boat configuration. The piperazine ring displays a chair conformation with the 2-phenyl-ethyl substituent assuming an equatorial orientation. There are two crystallographically independent, but virtually identical, mol­ecules in the asymmetric unit

Ethyl (E)-2-methoxy­imino-2-(4-nitro­benzo­yl)acetate

The title mol­ecule, C12H12N2O6, features an E conformation about the oxime group. The methoxy­imino and ester residues are effectively coplanar with each other (r.m.s. deviation for the nine non-H atoms = 0.127 Å) and almost orthogonal [with dihedral angles of 99.44 (13) and −77.85 (13)°, respectively] to the carbonyl and nitro­phenyl groups which lie to either side of this central plane. The crystal structure is consolidated by C—H⋯O contacts

(Z)-Ethyl 2-hydroxy­imino-2-(4-nitro­benz­yl)ethanoate

The title mol­ecule, C11H10N2O6, has a Z conformation about the C=N bond of the oxime unit. There are significant twists from planarity throughout the mol­ecule, the most significant being between the hydroxy­imino and ester groups which are effectively orthogonal with an N—C—C—Ocarbon­yl torsion angle of 91.4 (2)°. The crystal packing features oxime–benzoyl O—H⋯O contacts that lead to chains along [010] and C—H⋯O interactions also occur