Corn (Zea mays L.) defoliation experiments have been conducted for more than 120 years. However, there is limited data on the effect of row width on defoliation in modern hybrids. A two-year experiment was conducted in Lexington, Kentucky with two hybrids (113 relative maturity (RM) and 120 RM), two row widths (38 and 76 cm) and a combination of defoliation timings and severities: 0% defoliation (control), V7-100%, V14-50%, V14-100%, R2-50% and R2-100%. No yield difference among hybrids was observed in 2012. Yields were 26% greater in 38-cm rows than 76-cm rows in 2012. For 2013, corn yield for 38-cm was 10% greater, but hybrid, row width and defoliation interacted. Lowest yields were caused by V14-100% followed by R2-100%. Defoliations of V14-50% and R2-50% reduced yields in some cases. Complete defoliations at V7 did not reduce yields in most comparisons. Light interception below 80% during the critical period was enough to attain maximum yields in defoliated plants. Kernel number and kernel weight were most reduced by V14-100% and R2-100% defoliations, respectively. There is a potential for narrow rows to reduce grain yield losses after a defoliation event, when compared with wide rows.

The strive for a time-efficient construction process naturally put focus on the possibility of reducing the time of waiting between stages of construction, thereby minimizing the construction cost. If recently placed concrete, cast or sprayed, is exposed to impact vibrations at an early age while still in the process of hardening, damage that threatens the function of the hard concrete may occur. A waiting time when the concrete remains undisturbed, or a safe distance to the vibration source, is therefore needed. However, there is little, or no, fully proven knowledge of the length of this distance or time and there are no established guidelines for practical use. Therefore, conservative vibration limits are used for young and hardening concrete exposed to vibrations from e.g. blasting. As a first step in the dynamic analysis of a structure, the dynamic loads should always be identified and characterized. Here it is concluded that impact-type loads are the most dangerous of possible dynamic loads on young and hardening concrete. Shotcrete (sprayed concrete) on hard rock exposed to blasting and cast laboratory specimens subjected to direct mechanical impact loads have been investigated using finite element models based on the same analysis principles. Stress wave propagation is described in the same way whether it is through hard rock towards a shotcrete lining or through an element of young concrete. However, the failure modes differ for the two cases where shotcrete usually is damaged through loss of bond, partly or over larger sections that may result in shotcrete downfall. Cracking in shotcrete due to vibrations only is unusual and has not been observed during previous in situ tests. The study of shotcrete is included to demonstrate the need of specialized guidelines for cases other than for mass concrete, i.e. structural elements or concrete volumes with large dimensions in all directions. Within this project, work on evaluating and proposing analytical models are made in several steps, first with a focus on describing the behaviour of shotcrete on hard rock. It is demonstrated that wave propagation through rock towards shotcrete can be described using two-dimensional elastic finite element models in a dynamic analysis. The models must include the material properties of the rock and the accuracy of these parameters will greatly affect the results. It is possible to follow the propagation of stress waves through the rock mass, from the centre of blasting to the reflection at the shotcrete-rock interface. It is acceptable to use elastic material formulations until the strains are outside the elastic range, which thus indicates imminent material failure. The higher complexity of this type of model, compared with mechanical models using mass and spring elements, makes it possible to analyse more sophisticated geometries. Comparisons are made between numerical results and measurements from experiments in mining tunnels with ejected rock mass and shotcrete bond failure, and with measurements made during blasting for tunnel construction where rock and shotcrete remained intact. The calculated results are in good correspondence with the in situ observations and measurements, and with previous numerical modelling results. Examples of preliminary recommendations for practical use are given and it is demonstrated how the developed models and suggested analytical technique can be used for further detailed investigations. The modelling concept has also been used for analysis of impact loaded beams and concrete prisms modelled with 3D solid elements. As a first analysis step, an elastic material model was used to validate laboratory experiments with hammer-loaded concrete beams. The laboratory beam remained un-cracked during the experiments, and thus it was possible to achieve a good agreement using a linear elastic material model for fully hardened concrete. The model was further developed to enable modelling of cracked specimens. For verification of the numerical results, earlier laboratory experiments with hammer impacted smaller prisms of young concrete were chosen. A comparison between results showed that the laboratory tests can be reproduced numerically and those free vibration modes and natural frequencies of the test prisms contributed to the strain concentrations that gave cracking at high loads. Furthermore, it was investigated how a test prism modified with notches at the middle section would behave during laboratory testing. Calculated results showed that all cracking would be concentrated to one crack with a width equal to the sum of the multiple cracks that develop in un-notched prisms. In laboratory testing, the modified prism will provide a more reliable indication of when the critical load level is reached. This project has been interdisciplinary, combining structural dynamics, finite element modelling, concrete material technology, construction technology and rock support technology. It is a continuation from previous investigations of the effect on young shotcrete from blasting vibrations but this perspective has been widened to also include young, cast concrete. The outcome is a recommendation for how dynamic analysis of young concrete, cast and sprayed, can be carried out with an accurate description of the effect from impact-type loads. The type of numerical models presented and evaluated will provide an important tool for the work towards guidelines for practical use in civil engineering and concrete construction work. Some recommendations on safe distances and concrete ages are given, for newly cast concrete elements or mass concrete and for newly sprayed shotcrete on hard rock. / <p>QC 20150529</p>

No description available.

Transverse cracking in bridge decks has been found to be a rising problem for slab-on-girder bridges. In response to the concern, this research examined the influence of structural parameters and developed an analytical truss model, based on finite element modelling responses, for predicting the condition of long term cracking. Crack widths predicted using the truss model are very similar to that measured in a recent survey of Ontario highway overpass bridges. The approach to control cracking in deck slabs through structural design decisions enables engineers to provide high cracking resistance at locations of the bridge deck that are most likely to crack. Recommendations were made, based on the findings obtained from two sets of parametric studies, to help ensure transverse cracking in bridge decks is properly controlled for typical slab-on-girder bridges designed using the empirical design method specified in the current Canadian Highway Bridge Design Code.

Transverse cracking in bridge decks has been found to be a rising problem for slab-on-girder bridges. In response to the concern, this research examined the influence of structural parameters and developed an analytical truss model, based on finite element modelling responses, for predicting the condition of long term cracking. Crack widths predicted using the truss model are very similar to that measured in a recent survey of Ontario highway overpass bridges. The approach to control cracking in deck slabs through structural design decisions enables engineers to provide high cracking resistance at locations of the bridge deck that are most likely to crack. Recommendations were made, based on the findings obtained from two sets of parametric studies, to help ensure transverse cracking in bridge decks is properly controlled for typical slab-on-girder bridges designed using the empirical design method specified in the current Canadian Highway Bridge Design Code.

Line current distortion is an important issue to a high-power current source rectifier(CSR) system. There are two main challenges related to this issue. First, the CSR input LC resonance can be affected by the variation of the source inductance from the power system and the effects of the CSR DC side circuit, which may lead to a line current distortion higher than expected. Another challenge is that the traditional high-power CSR using Selective Harmonic Elimination (SHE) pulse-width modulation (PWM) technique attempts to eliminate certain harmonics in the PWM current, which limits its ability for line current harmonic control. To control the CSR line current harmonics, this thesis focuses on two aspects: 1) the analysis and design of CSR input filter to avoid unexpected input LC resonance, and 2) the development of a new PWM scheme that can compensate the effects of the grid voltage harmonics and DC link current ripples. The thesis work has been validated by simulations and on an experimental CSR prototype. / Power Engineering and Power Electronics

In this thesis, the possibility to numerically describing the behaviour that signifies shear type cracking in concrete is studied. Different means for describing cracking are evaluated where both methods proposed in design codes based on experiments and advanced finite element analyses with a non-linear material description are evaluated. It is shown that there is a large difference in the estimation of the crack width based on the calculation methods in design codes. The large difference occurs due to several of these methods do not account for shear friction in the crack face. The finite element method is an important tool for analysing the non-linear behaviour caused by cracking. It is especially of importance when combined with experimental investigations for evaluating load bearing capacity or establishing the structural health. It is shown that non-linear continuum material models can successfully be used to accurately describe the shear type cracking in concrete. A method based on plasticity and damage theory was shown to provide accurate estimations of the behaviour. The methods based on fracture mechanics with or without inclusion of damage theory, overestimated the stiffness after crack initiation considerably. The rotated crack approach of these methods gave less accurate descriptions of the crack pattern and underestimated the crack widths. After verification of the material model, realistic finite element models based on plasticity and damage theory are developed to analyse the cause for cracking in two large concrete structures. The Storfinnforsen hydropower buttress dam is evaluated where the seasonal temperature variation in combination with the water pressure have resulted in cracking. With the numerical model the cause for cracking can be explained and the crack pattern found in-situ is accurately simulated. The model is verified against measurements of variation in crest displacement and crack width with close agreement. The construction process of a balanced cantilever bridge, Gröndal Bridge, is numerically simulated and a rational explanation of the cause for cracking is presented. It is shown that large stresses and micro-cracks develop in the webs during construction, especially after tensioning the continuing tendons in the bottom flange. Further loads from temperature variation cause cracking in the webs that is in close agreement with the cracking found in-situ. The effect of strengthening performed on this bridge is also evaluated where the vertical Dywidag tendons so far seem to have been successful in stopping further crack propagation. / QC 20100730

This study investigated arch dimension changes associated with growth and tooth wear in Australian Aboriginals aged from age 8 to 15 years using 2D and 3D digital imaging systems. Serial dental casts of Australian Aboriginals from Yuendumu were used in the study. The sample comprised 25 females and 24 males for whom casts were available at ages of 8, 12 and 15 years ( a total of 294 dental study casts). The primary method of data acquisition involved obtaining digital photographs and digitizing the images using an Apple IIGS computer and customised software program. A subset of 40 dental stone models (5 individuals at ages 8, 12, 15 and 18 years) were duplicated and scanned using the Minolta Vivid 900 laser surface scanner at the DSIRO Laboratories, National University Singapore. The 3-D images were digitised using the Rapidform software package (Inus, technology, Seoul, Korea). Study variables included mesiodistal crown diameters, arch widths, arch depths and arch lengths. Mesiodistal crown dimensions in males tended to be larger than those in females. All arch dimensions were significantly larger in males than females. Upper and lower Intercanine width increased from age 8 to age 12 years but did not change thereafter. Upper and lower intermolar widths increased with age from 8 years to 15 years while arch depth decreased. No significant reduction in arch lengths was found from age 12 to 15 years. The two imaging systems were comparable in their measurement reliability, although the 2D method provided consistently larger crown diameters than the 3D method. Changes in arch dimensions with age in the Aboriginal sample were similar to those reported for other populations. However, no measurable change was detected in arch length over time, even though the Aboriginals had abrasive diets that would be expected to contribute to interproximal wear. It was concluded that the 2D and 3D imaging methods were suitable for clinical use but would require further refinement for research projects aimed at assessing minor changes in arch lengths associated with interproximal wear. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1347947 / Thesis (D.Clin.Dent.) -- University of Adelaide, School of Dentistry, 2008

This thesis examines the historical development and current state of amendment law in the Australian patent system. Initial research on modern amendment cases immediately showed that the confused, inconsistent and complex state of the law is a significant problem. There is a plethora of different analytical tools and legal tests being applied to assess an amendment, yet they were developed in a different area of patent law, that of fair basing. Such tools and tests are ill equipped to provide any real assistance to decision-makers faced with assessing an amendment. In fact, they seem to lead decision-makers away from applying the correct investigation as set out in the amendment provisions of the legislation. The thesis examines the history of amendment law so as to place its discussion of the current problems in context and provide a better understanding of why the problems arose. Four major events are discussed in the thesis. Together, these events have shaped Australian amendment law over the past century: (i) the development and introduction of the “substantially larger than or substantially different from” test into the British and Australian statutory amendment provisions; (ii) the development and introduction of the concept of fair basing into British and Australian patent law; (iii) the development and introduction of the modern British and Australian statutory test for amendments and the tiered amendment scheme; and (iv) the analogies drawn in modern British and Australian cases between fair basing and amendment that ultimately led to fair basing tests being cross-applied in Australia to assess the allowability of amendments. The thesis shows how the very harsh early British treatment of requests for amendment ultimately led to statutory change. It also locates, for the first time, the common law origins of the notion of “fair basing.” The 1949 British legislation implemented a new and different statutory test that was intended to liberalise the whole area of amendment law. It also added the requirement of “fair basing” into the legislation. However, the thesis shows that this last development occurred via well-intentioned legislators with a significant misunderstanding of patent law. The notion of fair basing injected a great deal of uncertainty into an area of law that was previously settled. Theoretically, and in practical application, it caused problems. Then, when decision-makers sought guidance on the new amendment provision, they applied the tests developed in fair basing cases to assess amendments, with the consequent deleterious effects. The Australian experience largely mirrored the British experience until 1977 when the British Act changed. The significance of the thesis is that it clearly demonstrates that the currently accepted dogma – that fair basing is equivalent to the “in substance disclosure” statutory test for amendments, so fair basing tests can be used to assess amendment – is unsound. The thesis isolates the problems inherent in the dogma and the examination of relevant case law confirms the main hypothesis that the current approach should be rejected. It simply operates to the prejudice of inventors, their competitors, the public and the patent system itself. Most importantly, the thesis shows that reform is urgently needed. Some possibilities for reform are suggested.

Resumo: O objetivo do presente estudo foi avaliar alterações ao redor de implantes inseridos em diferentes níveis em relação à crista óssea, e sob diferentes protocolos de restauração. Trinta e seis implantes foram inseridos nas mandíbulas edêntulas de 6 cães. Três implantes foram instalados por hemi-mandíbula, cada qual representativo de um grupo experimental. Estes foram determinados de acordo com a distância entre a junção implante-conector protético (JIC) e a crista óssea: Ao Nível (ao nível da crista óssea), Menos 1 (1mm apical à crista óssea), ou Menos 2 (2mm apical à crista óssea). Cada hemi-mandíbula foi submetida a um protocolo de restauração: convencional (prótese instalada 120 dias após a implantação) ou imediata (prótese instalada 24 horas após a implantação). Parâmetros clínicos, radiográficos, e histométricos foram avaliados após 90 dias de restauração, e os dados foram analisados estatisticamente (alfa=5%). A posição da margem do tecido mole (PTM) não foi influenciada pelo posicionamento apical da JIC; entretanto, sítios submetidos à restauração imediata tiveram a PTM significantemente mais coronal que os submetidos à restauração convencional (p=0,02, análise clínica). A reabsorção do rebordo não foi estatisticamente diferente entre os grupos (p>0,05, análise radiográfica). Menores quantidades de Perda Óssea Lateral (POL) foram observadas nos sítios restaurados imediatamente em comparação com os restaurados convencionamente (p=0,006, análise histométrica). Os presentes achados sugerem que o posicionamento apical da JIC não põe em risco a altura de tecidos periimplantares moles ou duros. Além disto, a restauração imediata foi benéfica para manter a PTM, e minimizar a POL. / Abstract: The aim of the present study was to evaluate changes that occur around dental implants inserted in different levels in relation to crestal bone, under different restoration conditions. Thirty-six implants were inserted in the edentulous mandible of six dogs. Three implants were inserted per hemimandible, each one representing an experimental group according to the distance from the implant-abutment junction (IAJ) to the crestal bone: Bone Level (at crestal bone level), Minus 1 (1mm below crestal bone), or Minus 2 group (2mm below crestal bone). Each hemimandible was submitted to a restoration protocol: conventional (prothesis installed 120 days after implant placement) or immediate (prosthesis installed 24 hours after implant placement). Clinical, radiographic, and histometric parameters were evaluated after 90 days of restoration, and data was analyzed statistically (alpha=5%). The position of soft tissue margin (PSTM) was not influenced by the apical positioning of the IAJ; however, sites submitted to immediate restoration had the PSTM displayed significantly more coronally than those submitted to conventional restoration (p=0.02, clinical analysis). Ridge Loss was not statistically different among groups (p>0.05, radiographic analysis). Greater amounts of Lateral Bone Loss (LBL) were observed for conventionally than for immediately restored sites (p=0.006, histometric analysis). These findings suggest that the apical positioning of IAJ did not jeopardize the height of peri-implantar soft and hard tissues. Moreover, immediate restoration was beneficial to maintain the PSTM, and to minimize LBL. / Orientador: Elcio Marcantonio Junior / Coorientador: Joni Augusto Cirelli / Banca: Roberto Henrique Barbeiro / Banca: Marcio Fernando de Moraes Grisi / Banca: Mário Taba Junior / Banca: Sérgio Luís da Silva Pereira / Doutor