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

The Effects of Drugs on Neurotransmission in the Vas Deferens

1) The aim of this study was to investigate the effects of field stimulation and drugs on neurotransmission in the vas deferens. 2) Field stimulation of mouse isolated vasa resulted in biphasic motor responses that were abolished by tetrodotoxin (TTX). The initial component of this response was selectively inhibited by morphine and clonidine. The second component was inhibited by phentolamine. 3) After 6-hydroxydopamine (6-OHDA) pretreatment, field stimulation produced a small, monophasic contraction, which was unaffected by phentolamine and by TTX. Vasa from 6-OHDA pretreated mice were supersensitive to noradrenaline (NA). 4) In control anaesthetised rats, motor responses of the in situ vas to field stimulation or to spinal nerve stimulation were biphasic and were abolished by TTX. After 6-OHDA pretreatment, in situ field stimulation produced monophasic contractions that were resistant to TTX, suggesting that these responses may be non-neuronal, resulting from direct stimulation of supersensitive smooth muscle. 5) Morphine and clonidine potentiated the second noradrenergic component of the biphasic motor response to field stimulation at a time when the overflow of radioactivity from vasa preincubated with (3H)-NA was increased. 6) The ability of morphine and clonidine to potentiate the field stimulation-induced overflow of radioactivity occurred in the presence of a combination of drugs which block the removal mechanisms for NA. 7) NA and electrical field stimulation increased phosphoinositide hydrolysis, reflected in [32P]-phosphatidic acid (PA) formation in the mouse vas deferens and these responses were blocked by prazosin and by TTX. 8) Neither morphine nor clonidine affected basal levels of [32P]-PA formation or the ability of NA to enhance [32P]-PA formation but both drugs potentiated the ability of field stimulation to increase the formation of [32P]-PA. This suggests that these drugs enhance the field stimulation-induced release of NA in the mouse vas deferens. A possible explanation for the findings that morphine and clonidine apparently inhibit release of one co-transmitter whilst potentiating the release of another is discussed. 9) Part of the study investigated the effects of chronically treating mice with thyroxine (T4). The level of T4 in the serum was increased in mice pretreated with T4, and this was accompanied by changes in pre- and post-synaptic receptor sensitivity. 10) Pretreatment with T4 produced a presynaptic subsensitivity to morphine and clonidine and a postsynaptic subsensitivity to NA and carbachol. In these animals, the ability of morphine and clonidine to potentiate the overflow of (3H)-NA was diminished. A possible explanation for these observations is considered

The zwitterion 1-butylimidazolium-3- (n-butanesulfonate)

The mol&shy;ecule of the title compound, C11H20N2O3S, contains a positively charged imidazolium head group and a negatively charged sulfonate tethered together by a four-carbon chain. There is weak intermolecular hydrogen bonding within the structure between the sulfonate O atoms and the H atoms of the imidazolium ring. The sulfonate group causes a twisting of the butyl chain and a decrease in the dihedral angle between the second and third carbon chain compared to the unsubstituted butyl group.<br /

Analyses of Victorian hog deer (axis porcinus) checking station data: demographics, body condition and time of harvest

This report looks into the sustainability and health of deer within Victoria\u27s regional areas.&nbsp;Hog Deer (Axis porcinus) are a popular and highly valued game species in Victoria, with licensed hunters permitted to harvest one male and one female during an annual hunting season during the month of April. All harvested deer must be tagged and presented at a checking station within 24 hours of harvest. A variety of morphological and biological data are recorded for each harvested animal during inspection at the checking stations. The objectives of this study were to (i) summarise biological data collected for all Hog Deer inspected at the four mainland checking stations during 1997–2011 (i.e. excluding Sunday Island, which is owned and managed by the Para Park Co-operative Game Reserve Limited), and (ii) provide recommendations for improving the usefulness of future data collection. A total of 1122 deer were presented at the mainland checking stations (70.4% male; 29.6% female) during 1997–2011, with annual totals ranging from 38 in 1999 to 111 in 2011. There was little evidence that the number or sex ratio of deer harvested annually changed substantially over the course of the study period. The overall percentages of deer harvested on public (52%) and private (48%) land also did not show any discernable trend during the study period. The ages of deer (estimated by molar eruption and tooth wear) ranged from 1 to 12 years for females and males. Although the age structures differed slightly for females and males, there was no evidence that this changed over the study period, although inconsistent recording of ages limited the opportunity for quantitative analyses of these data

Assessing the relationships between late night drinks marketing and alcohol-related disorder in public space

In recent years there has been growing concern voiced about an apparent rise in alcohol-related public disorder or ‘binge drinking’ within the weekend night-time economy in the UK (e.g. Bright & Hinsliff, 2004; Iredale, 2004; Travis 2004; The Times, 2005). The problems associated with excessive alcohol consumption in public space have become unusually high profile in recent times. This is highlighted by the popularity of TV shows such as the BBC ‘fly-on-the-wall’ documentary series Drunk and dangerous, broadcast in early 2004 or the Bravo satellite TV channel series Booze Britain, broadcast twice daily later that year and Booze Britain II: Binge Nation the year after. Such behaviours have even been receiving publicity in an apparently perplexed foreign media (e.g. Altaner & Monaghan, 2004; Bamber, 2005; Jolly, 2004) and to the extent that Prime Minister Tony Blair has described this pattern of behaviour as “the new sort of British disease” (Morris, 2004)

Diazepam, alcohol use and violence among male young offenders: 'the devil's mixture’

Citation for published version (APA): Forsyth, A., Khan, F., &amp; McKinlay, W. (2011). Diazepam, alcohol use and violence among male young offenders: &apos;the devil&apos;s mixture’. Drugs: Education, Prevention and Policy, 18(6), 468-476. 10.3109/09687637.2011.563762 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the ResearchOnline@GCU portal Take down polic

Structure and spacing of cellulose microfibrils in woody cell walls of dicots

The structure of cellulose microfibrils in situ in wood from the dicotyledonous (hardwood) species cherry and birch, and the vascular tissue from sunflower stems, was examined by wide-angle X-ray and neutron scattering (WAXS and WANS) and small-angle neutron scattering (SANS). Deuteration of accessible cellulose chains followed by WANS showed that these chains were packed at similar spacings to crystalline cellulose, consistent with their inclusion in the microfibril dimensions and with a location at the surface of the microfibrils. Using the Scherrer equation and correcting for considerable lateral disorder, the microfibril dimensions of cherry, birch and sunflower microfibrils perpendicular to the [200] crystal plane were estimated as 3.0, 3.4 and 3.3 nm respectively. The lateral dimensions in other directions were more difficult to correct for disorder but appeared to be 3 nm or less. However for cherry and sunflower, the microfibril spacing estimated by SANS was about 4 nm and was insensitive to the presence of moisture. If the microfibril width was 3 nm as estimated by WAXS, the SANS spacing suggests that a non-cellulosic polymer segment might in places separate the aggregated cellulose microfibrils

A potential anti-corrosive ionic liquid coating for MG alloy AZ31 in simulated body fluids

Magnesium alloys are attractive materials for biomedical applications, due to their excellent biocompatibility. However, these alloys show fast corrosion rates in the body that limits their clinical applications. Low-toxic ionic liquid (IL) trimethyl(butyl)phosphonium diphenyl phosphate P1444dpp has been investigated to provide corrosion protection for magnesium alloy AZ31 in simulated body fluids (SBFs). This work reports a preliminary exploration of the influence of different treatment temperatures on the corrosion protection properties of IL films for the magnesium alloy AZ31 in SBFs. Results show that the IL treatment at room temperature did not bring significant improvement in the corrosion performance of the AZ31 in SBF. However, when the treatment temperature was increased to 75&deg;C, the IL treatment resulted in a substantial reduction of the corrosion, in particular the reduction of localized pitting corrosion. The influence of ionic liquid treatment on the corrosion performance of the magnesium alloys AZ31 in SBFs has been investigated by electrochemical impedance spectroscopy (EIS) tests and immersion tests