Surface effects on the dual-mode vibration of <110> silver nanowires with different cross-sections

Dual-mode vibration of nanowires has been reported experimentally through actuation of the nanowire at its resonance frequency, which is expected to open up a variety of new modalities for the NEMS that could operate in the nonlinear regime. In the present work, we utilize large scale molecular dynamics simulations to investigate the dual-mode vibration of <110> Ag nanowires with triangular, rhombic and truncated rhombic cross-sections. By incorporating the generalized Young-Laplace equation into Euler-Bernoulli beam theory, the influence of surface effects on the dual-mode vibration is studied. Due to the different lattice spacing in principal axes of inertia of the {110} atomic layers, the NW is also modeled as a discrete system to reveal the influence from such specific atomic arrangement. It is found that the <110> Ag NW will under a dual-mode vibration if the actuation direction is deviated from the two principal axes of inertia. The predictions of the two first mode natural frequencies by the classical beam model appear underestimated comparing with the MD results, which are found to be enhanced by the discrete model. Particularly, the predictions by the beam theory with the contribution of surface effects are uniformly larger than the classical beam model, which exhibit better agreement with MD results for larger cross-sectional size. However, for ultrathin NWs, current consideration of surface effects is still experiencing certain inaccuracy. In all, for all different cross-sections, the inclusion of surface effects is found to reduce the difference between the two first mode natural frequencies. This trend is observed consistent with MD results. This study provides a first comprehensive investigation on the dual-mode vibration of <110> oriented Ag NWs, which is supposed to benefit the applications of NWs that acting as a resonating beam.

Preliminary Design and Performance Estimation of Radial Inflow Turbines: An Automated Approach

A comprehensive one-dimensional meanline design approach for radial inflow turbines is described in the present work. An original code was developed in Python that takes a novel approach to the automatic selection of feasible machines based on pre-defined performance or geometry characteristics for a given application. It comprises a brute-force search algorithm that traverses the entire search space based on key non-dimensional parameters and rotational speed. In this study, an in-depth analysis and subsequent implementation of relevant loss models as well as selection criteria for radial inflow turbines is addressed. Comparison with previously published designs, as well as other available codes, showed good agreement. Sample (real and theoretical) test cases were trialed and results showed good agreement when compared to other available codes. The presented approach was found to be valid and the model was found to be a useful tool with regards to the preliminary design and performance estimation of radial inflow turbines, enabling its integration with other thermodynamic cycle analysis and three-dimensional blade design codes.

Candidate radial-inflow turbines and high-density working fluids for geothermal power systems

Optimisation of Organic Rankine Cycles (ORCs) for binary-cycle geothermal applications could play a major role in the competitiveness of low to moderate temperature geothermal resources. Part of this optimisation process is matching cycles to a given resource such that power output can be maximised. Two major and largely interrelated components of the cycle are the working fluid and the turbine. Both components need careful consideration. Due to the temperature differences in geothermal resources a one-size-fits-all approach to surface power infrastructure is not appropriate. Furthermore, the traditional use of steam as a working fluid does not seem practical due to the low temperatures of many resources. A variety of organic fluids with low boiling points may be utilised as ORC working fluids in binary power cycle loops. Due to differences in thermodynamic properties, certain fluids are able to extract more heat from a given resource than others over certain temperature and pressure ranges. This enables the tailoring of power cycle infrastructure to best match the geothermal resource through careful selection of the working fluid and turbine design optimisation to yield the optimum overall cycle performance. This paper presents the rationale for the use of radial-inflow turbines for ORC applications and the preliminary design of several radial-inflow turbines based on a selection of promising ORC cycles using five different high-density working fluids: R134a, R143a, R236fa, R245fa and n-Pentane at sub- or trans-critical conditions. Numerous studies published compare a variety of working fluids for various ORC configurations. However, there is little information specifically pertaining to the design and implementation of ORCs using realistic radial turbine designs in terms of pressure ratios, inlet pressure, rotor size and rotational speed. Preliminary 1D analysis leads to the generation of turbine designs for the various cycles with similar efficiencies (77%) but large differences in dimensions (139289 mm rotor diameter). The highest performing cycle (R134a) was found to produce 33% more net power from a 150°C resource flowing at 10 kg/s than the lowest performing cycle (n-Pentane).

Shear thinning and shear thickening non-Newtonian confined fluid flow over rotating cylinder

In present work, numerical solution is performed to study the confined flow of power-law non Newtonian fluids over a rotating cylinder. The main purpose is to evaluate drag and thermal coefficients as functions of the related governing dimensionless parameters, namely, power-law index (0.5 ≤ n ≤ 1.4), dimensionless rotational velocity (0 ≤ α ≤ 6) and the Reynolds number (100 ≤ Re ≤ 500). Over the range of Reynolds number, the flow is known to be steady. Results denoted that the increment of power law index and rotational velocity increases the drag coefficient due to momentum diffusivity improvement which is responsible for low rate of heat transfer, because the thicker the boundary layer, the lower the heat transfer is implemented.

Heavy Weather

Heavy Weather was a monumental sculptural work produced for the prestigious McClelland National Sculpture Survey in 2012. The work was a large cold-cast aluminium figure depicting the artist in athletic costume arching backwards across the top of massive boulder. The pose of the figure was derived from the ‘Fosbury flop’, the awkward backwards manoeuvre associated with high-jump event. The boulder was a portrait of a different kind - a remake of the Ian Fairweather memorial on Bribie Island but elongated to tower upwards. The work thus emphasised two contrasting impressions of movement – immense inertia and writhing agility. Heavy Weather sought to bring these two opposing forces together as a way of representing the tensions that shape our relationship with objects. In so doing, the work contributed to the artist’s ongoing exploration of sculpture, self-portraiture and the civic monument. The work was promoted nationally including the Art Guide and the Melbourne Review. It was also the subject of a article in the Australian Art Collector.

Active and reactive power control of synchronous generator for the realization of a virtual power plant

This paper presents a novel power control strategy that decouples the active and reactive power for a synchronous generator connected to a power network. The proposed control paradigm considers the capacitance of the transmission line along with its resistance and reactance as-well. Moreover the proposed controller takes into account all cases of R-X relationships, thus allowing it to function in Virtual Power Plant (VPP) structures which operate at both medium voltage (MV) and low voltage (LV) levels. The independent control of active and reactive power is achieved through rotational transformations of the terminal voltages and currents at the synchronous generator's output. This paper details the control technique by first presenting the mathematical and electrical network analysis of the methodology and then successfully implementing the control using MATLAB-SIMULINK simulation.

Cement-in-cement revision for selected Vancouver Type B1 femoral periprosthetic fractures : A biomechanical analysis

The aim of this study was to perform a biomechanical analysis of the cement-in-cement (c-in-c) technique for fixation of selected Vancouver Type B1 femoral periprosthetic fractures and to assess the degree of cement interposition at the fracture site. Six embalmed cadaveric femora were implanted with a cemented femoral stem. Vancouver Type B1 fractures were created by applying a combined axial and rotational load to failure. The femora were repaired using the c-in-c technique and reloaded to failure. The mean primary fracture torque was 117 Nm (SD 16.6, range 89–133). The mean revision fracture torque was 50 Nm (SD 16.6, range 29–74), which is above the torque previously observed for activities of daily living. Cement interposition at the fracture site was found to be minimal.

Damage assessment in reinforced concrete flexural members using modal strain energy based method

Damage assessment (damage detection, localization and quantification) in structures and appropriate retrofitting will enable the safe and efficient function of the structures. In this context, many Vibration Based Damage Identification Techniques (VBDIT) have emerged with potential for accurate damage assessment. VBDITs have achieved significant research interest in recent years, mainly due to their non-destructive nature and ability to assess inaccessible and invisible damage locations. Damage Index (DI) methods are also vibration based, but they are not based on the structural model. DI methods are fast and inexpensive compared to the model-based methods and have the ability to automate the damage detection process. DI method analyses the change in vibration response of the structure between two states so that the damage can be identified. Extensive research has been carried out to apply the DI method to assess damage in steel structures. Comparatively, there has been very little research interest in the use of DI methods to assess damage in Reinforced Concrete (RC) structures due to the complexity of simulating the predominant damage type, the flexural crack. Flexural cracks in RC beams distribute non- linearly and propagate along all directions. Secondary cracks extend more rapidly along the longitudinal and transverse directions of a RC structure than propagation of existing cracks in the depth direction due to stress distribution caused by the tensile reinforcement. Simplified damage simulation techniques (such as reductions in the modulus or section depth or use of rotational spring elements) that have been extensively used with research on steel structures, cannot be applied to simulate flexural cracks in RC elements. This highlights a big gap in knowledge and as a consequence VBDITs have not been successfully applied to damage assessment in RC structures. This research will address the above gap in knowledge and will develop and apply a modal strain energy based DI method to assess damage in RC flexural members. Firstly, this research evaluated different damage simulation techniques and recommended an appropriate technique to simulate the post cracking behaviour of RC structures. The ABAQUS finite element package was used throughout the study with properly validated material models. The damaged plasticity model was recommended as the method which can correctly simulate the post cracking behaviour of RC structures and was used in the rest of this study. Four different forms of Modal Strain Energy based Damage Indices (MSEDIs) were proposed to improve the damage assessment capability by minimising the numbers and intensities of false alarms. The developed MSEDIs were then used to automate the damage detection process by incorporating programmable algorithms. The developed algorithms have the ability to identify common issues associated with the vibration properties such as mode shifting and phase change. To minimise the effect of noise on the DI calculation process, this research proposed a sequential order of curve fitting technique. Finally, a statistical based damage assessment scheme was proposed to enhance the reliability of the damage assessment results. The proposed techniques were applied to locate damage in RC beams and slabs on girder bridge model to demonstrate their accuracy and efficiency. The outcomes of this research will make a significant contribution to the technical knowledge of VBDIT and will enhance the accuracy of damage assessment in RC structures. The application of the research findings to RC flexural members will enable their safe and efficient performance.

2-[(3,3-Dimethylindolin-2-ylidene)methyl]-4-[(3,3-dimethyl-3H-indol-1-ium-2-yl)methylidene]-3-oxocyclobut-1-en-1-olate chloroform disolvate

In the title squaraine dye solvate, C26H24N2O2·2CHCl3, the dye molecule is essentially planar, except for the methyl groups, having a maximum deviation over the 26-membered delocalized bond system of 0.060 (2) Å. It possesses crystallographic twofold rotational symmetry with the indole ring systems adopting a syn conformation. The molecular structure features intramolecular N-HO hydrogen bonds enclosing conjoint S7 ring motifs about one of the dioxocyclobutene O atoms, while the two chloroform solvent molecules are linked to the second O atom through C-HO hydrogen bonds.

Water Sensitive Urban Design (WSUD) application auditing

Background WSUD implementation in the Gold Coast City Council area commenced more than a decade ago. As a result, Council is expected to be in possession of WSUD assets valued at over tens of million dollars. The Gold Coast City Council is responsible for the maintenance and long-term management of these WSUD assets. Any shortcoming in implementation of best WSUD practices can potentially result in substantial liabilities and ineffective expenditure for the Council in addition to reduced efficiencies and outcomes. This highlights the importance of periodic auditing of WSUD implementation. Project scope The overall study entailed the following tasks: * A state-of-the-art literature review of the conceptual hydraulic and water quality treatment principles, current state of knowledge in relation to industry standards, best practice and identification of knowledge gaps in relation to maintenance and management practices and potential barriers to the implementation of WSUD. * Council stakeholder interviews to understand current practical issues in relation to the implementation of WSUD and the process of WSUD application from development application approval to asset management. * Field auditing of selected WSUD systems for condition assessment and identification of possible strengths and weaknesses in implementation. * Review of the Land Development Guidelines in order to identify any gaps and to propose recommendations for improvement. Conclusions Given below is a consolidated summary of the findings of the study undertaken. State-of-the-art literature review Though the conceptual framework for WSUD implementation is well established, the underlying theoretical knowledge underpinning the treatment processes and maintenance regimes and life cycle costing are still not well understood. Essentially, these are the recurring themes in the literature, namely, the inadequate understanding of treatment processes and lack of guidance to ensure specificity of maintenance regimes and life cycle costing of WSUDs. The fundamental barriers to successful WSUD implementation are: * Lack of knowledge transfer – This essentially relates to the lack of appropriate dissemination of research outcomes and the common absence of protocols for knowledge transfer within the same organisation. * Cultural barriers – These relate to social and institutional factors, including institutional inertia and the lack of clear understanding of the benefits. * Fragmented responsibilities – This results from poor administrative integration within local councils in relation to WSUDs. * Technical barriers – These relate to lack of knowledge on operational and maintenance practices which is compounded by model limitations and the lack of long-term quantitative performance evaluation data. * Lack of engineering standards – Despite the availability of numerous guidelines which are non-enforceable and can sometimes be confusing, there is a need for stringent engineering standards. The knowledge gaps in relation to WSUDs are only closing very slowly. Some of the common knowledge gaps identified in recent publications have been recognised almost a decade ago. The key knowledge gaps identified in the published literature are: * lack of knowledge on operational and maintenance practices; * lack of reliable methodology for identifying life cycle issues including costs; * lack of technical knowledge on system performance; * lack of guidance on retrofitting in existing developments. Based on the review of barriers to WSUD implementation and current knowledge gaps, the following were identified as core areas for further investigation: * performance evaluation of WSUD devices to enhance model development and to assess their viability in the context of environmental, economic and social drivers; establishing realistic life cycle costs to strengthen maintenance and asset management practices; * development of guidelines specific to retrofitting in view of the unique challenges posed by existing urban precincts together with guidance to ensure site specificity; establishment of a process for knowledge translation for enhancing currently available best practice guidelines; * identification of drivers and overcoming of barriers in the areas of institutional fragmentation, knowledge gaps and awareness of WSUD practices. GCCC stakeholder interviews Fourteen staff members involved in WSUD systems management in the Gold Coast City Council, representing four Directorates were interviewed using a standard questionnaire. The primary issues identified by the stakeholders were: * standardisation of WSUD terminology; * clear protocols for safeguarding devices during the construction phase; * engagement of all council stakeholders in the WSUD process from the initial phase; * limitations in the Land Development Guidelines; * ensuring public safety through design; * system siting to avoid conflicts with environmental and public use of open space; * provision of adequate access for maintenance; * integration of social and ecosystem issues to ensure long-term viability of systems in relation to both, vandalism and visual recreation; * lack of performance monitoring and inadequacy of the maintenance budget; * lack of technical training for staff involved in WSUD design approvals and maintenance; incentives for developers for acting responsibly in stormwater management. Field auditing of WSUD systems A representative cross section of WSUD systems in the Gold Coast were audited in the field. The following strengths and weaknesses in WSUD implementation were noted: * The implementation of WSUD systems in the field is not consistent. * The concerns raised by the stakeholders during the interviews in relation to WSUD implementation was validated from the observations from the field auditing, particularly in relation to the following: * safeguarding of devices during the construction phase * public safety * accessibility for maintenance * lack of performance monitoring by Council to assess system performance * inadequate maintenance of existing systems to suit site specific requirements. * A treatment train approach is not being consistently adopted. * Most of the systems audited have satisfactorily catered for public safety. Accessibility for maintenance has been satisfactorily catered for in most of the systems that were audited. * Systems are being commissioned prior to construction activities being substantially completed. * The hydraulic design of most systems appears to be satisfactory. * The design intent of the systems is not always clear. Review of Land Development Guidelines The Land Development Guidelines (TDG) was extensively reviewed and the following primary issues were noted in relation to WSUD implementation: * the LDG appears to have been prepared primarily to provide guidance to developers. It is not clear to what extent the guidelines are applicable to Council staff involved in WSUD maintenance and management; * Section 13 is very voluminous and appears to be a compilation of a series of individual documents resulting in difficulties in locating specific information, a lack of integration and duplication of information; * the LDG has been developed with a primary focus on new urban precinct development and the retrofitting of systems in existing developments has not been specifically discussed; * WSUDs are discussed in two different sections in the LDG and it is not clear which section takes precedence as there are inconsistencies between the two sections; there is inconsistent terminology being used; * there is a need for consolidation of information provided in different sections in the LDG; * there are inconsistencies in the design criteria provided; * there is a need for regular updating of the LDG to ensure that the information provided encompasses the state-of-the-art; * there is limited guidance provided for the preparation of maintenance plans and life cycle costing to assist developers in asset handover and to assist Council staff in assessment. * Based on these observations, eleven recommendations have been provided which are discussed below. Additionally, the stakeholder provided the following specific comments during the interviews in relation to the LDG: * lack of flexibility to cover the different stages of the life cycle of the systems; * no differentiation in projects undertaken by developers and Council; * inadequate information with regards to safety issues such as maximum standing water depth, fencing and safety barriers and public access; * lack of detailed design criteria in relation to Crime Prevention through Environmental Design, safety, amenity, environment, surrounding uses and impacts on surroundings; * inadequate information regarding maintenance requirements specific to the assessment and compliance phases; * recommendations for plantings are based primarily on landscape requirements rather than pollutant uptake capability. Recommendations With regards to the Land Development Guidelines, the following specific recommendations are provided: 1. the relevant sections and their extent of applicability to Council should be clearly identified; 2. integration of the different subsections within Section 13 and re-formatting the document for easy reference; 3. the maintenance guidelines provided in Section 13 should be translated to a maintenance manual for guidance of Council staff; 4. should consider extending the Guidelines to specifically encompass retrofitting of WSUD systems to existing urban precincts; 5. Section 3 needs to be revised to be made consistent with Section 13, to ensure priority for WSUD practices in urban precincts and to move away from conventional stormwater drainage design such as kerb and channelling; 6. it would also be good to specify as to which Section takes predominance in relation to stormwater drainage. It is expected that Section 13 would take predominance over the other sections in the LDG; 7. terminology needs to be made consistent to avoid confusion among developers and Council staff. Water Sensitive Urban Design is the term commonly used in Australia for stormwater quality treatment, rather than Stormwater Quality Improvement Devices. This once again underlines the need for ensuring consistency between Section 3 and Section 13; 8. it would also be good if there is a glossary of commonly used terms in relation to WSUD for use by all stakeholders and which should also be reflected in the LDG; 9. consolidation of all WSUD information into one section should be considered together with appropriate indicators in other LDG Sections regarding the availability of WSUD information. Ensuring consistency in the information provided is implied; 10. Section 13 should be updated at regular intervals to ensure the incorporation of the latest in research outcomes and incorporating criteria and guidance based on the state-of-the-art knowledge. The updating could be undertaken, say, in five year cycles. This would help to overcome the current lack of knowledge transfer; 11. the Council should consider commissioning specialised studies to extend the current knowledge base in relation to WSUD maintenance and life cycle costing. Additionally, Recommendation 10 is also applicable in this instance. The following additional recommendations are made based on the state-of-the-art literature review, stakeholder interviews and field auditing of WSUD systems: 1. Performance monitoring of existing systems to assess improvements to water quality, identify modifications and enhancements to improve performance; 2. Appropriate and monitored maintenance during different phases of development of built assets over time is needed to investigate the most appropriate time/phase of development to commission the final WSUD asset. 3. Undertake focussed investigations in the areas of WSUD maintenance and asset management in order to establish more realistic life cycle costs of systems and maintenance schedules; 4. the engagement of all relevant Council stakeholders from the initial stage of concept planning through to asset handover, and ongoing monitoring. This close engagement of internal stakeholders will assist in building a greater understanding of responsibilities and contribute to overcoming constraints imposed by fragmented responsibilities; 5. the undertaking of a public education program to inform the community of the benefits and ecosystem functions of WSUD systems; 6. technical training to impart state-of-the-art knowledge to staff involved in the approval of designs and maintenance and management of WSUD projects; 7. during the construction phase, it is important to ensure that appropriate measures to safeguard WSUD devices are implemented; 8. risks associated with potential public access to open water zones should be minimised with the application of appropriate safety measures; 9. system siting should ensure that potential conflicts are avoided with respect to public and ecosystem needs; 10. integration of social and ecosystem issues to ensure long-term viability of systems; provide incentives to developers who are proactive and responsible in the area of stormwater management.

Measurement of a PAGAT gel dosimeter by ultrasound computed tomography

In this work we used a 3D quantitative CT ultrasound imaging system to characterise polymer gel dosimeters. The system comprised of two identical 5 MHz 128 element phased-array ultrasound transducers co-axially aligned and submerged in water as a coupling agent. Rotational and translational movement of the gel dosimeter sample between the transducers were performed using a robotic arm. Ultrasound signals were generated and received using an Olympus Omniscan unit. Dose sensitivity of attenuation and time of flight ultrasonic parameters were assessed using this system.

Genetic improvement of giant freshwater prawn in Vietnam

The giant freshwater prawn (Macrobrachium rosenbergii) or GFP is one of the most important freshwater crustacean species in the inland aquaculture sector of many tropical and subtropical countries. Since the 1990’s, there has been rapid global expansion of freshwater prawn farming, especially in Asian countries, with an average annual rate of increase of 48% between 1999 and 2001 (New, 2005). In Vietnam, GFP is cultured in a variety of culture systems, typically in integrated or rotational rice-prawn culture (Phuong et al., 2006) and has become one of the most common farmed aquatic species in the country, due to its ability to grow rapidly and to attract high market price and high demand. Despite potential for expanded production, sustainability of freshwater prawn farming in the region is currently threatened by low production efficiency and vulnerability of farmed stocks to disease. Commercial large scale and small scale GFP farms in Vietnam have experienced relatively low stock productivity, large size and weight variation, a low proportion of edible meat (large head to body ratio), scarcity of good quality seed stock. The current situation highlights the need for a systematic stock improvement program for GFP in Vietnam aimed at improving economically important traits in this species. This study reports on the breeding program for fast growth employing combined (between and within) family selection in giant freshwater prawn in Vietnam. The base population was synthesized using a complete diallel cross including 9 crosses from two local stocks (DN and MK strains) and a third exotic stock (Malaysian strain - MY). In the next three selection generations, matings were conducted between genetically unrelated brood stock to produce full-sib and (paternal) half-sib families. All families were produced and reared separately until juveniles in each family were tagged as a batch using visible implant elastomer (VIE) at a body size of approximately 2 g. After tags were verified, 60 to 120 juveniles chosen randomly from each family were released into two common earthen ponds of 3,500 m2 pond for a grow-out period of 16 to 18 weeks. Selection applied at harvest on body weight was a combined (between and within) family selection approach. 81, 89, 96 and 114 families were produced for the Selection line in the F0, F1, F2 and F3 generations, respectively. In addition to the Selection line, 17 to 42 families were produced for the Control group in each generation. Results reported here are based on a data set consisting of 18,387 body and 1,730 carcass records, as well as full pedigree information collected over four generations. Variance and covariance components were estimated by restricted maximum likelihood fitting a multi-trait animal model. Experiments assessed performance of VIE tags in juvenile GFP of different size classes and individuals tagged with different numbers of tags showed that juvenile GFP at 2 g were of suitable size for VIE tags with no negative effects evident on growth or survival. Tag retention rates were above 97.8% and tag readability rates were 100% with a correct assignment rate of 95% through to mature animal size of up to 170 g. Across generations, estimates of heritability for body traits (body weight, body length, cephalothorax length, abdominal length, cephalothorax width and abdominal width) and carcass weight traits (abdominal weight, skeleton-off weight and telson-off weight) were moderate and ranged from 0.14 to 0.19 and 0.17 to 0.21, respectively. Body trait heritabilities estimated for females were significantly higher than for males whereas carcass weight trait heritabilities estimated for females and males were not significantly different (P > 0.05). Maternal and common environmental effects for body traits accounted for 4 to 5% of the total variance and were greater in females (7 to 10%) than in males (4 to 5%). Genetic correlations among body traits were generally high in both sexes. Genetic correlations between body and carcass weight traits were also high in the mixed sexes. Average selection response (% per generation) for body weight (transformed to square root) estimated as the difference between the Selection and the Control group was 7.4% calculated from least squares means (LSMs), 7.0% from estimated breeding values (EBVs) and 4.4% calculated from EBVs between two consecutive generations. Favourable correlated selection responses (estimated from LSMs) were detected for other body traits (12.1%, 14.5%, 10.4%, 15.5% and 13.3% for body length, cephalothorax length, abdominal length, cephalothorax width and abdominal width, respectively) over three selection generations. Data in the second selection generation showed positive correlated responses for carcass weight traits (8.8%, 8.6% and 8.8% for abdominal weight, skeleton-off weight and telson-off weight, respectively). Data in the third selection generation showed that heritability for body traits were moderate and ranged from 0.06 to 0.11 and 0.11 to 0.22 at weeks 10 and 18, respectively. Body trait heritabilities estimated at week 10 were not significantly lower than at week 18. Genetic correlations between body traits within age and genetic correlations for body traits between ages were generally high. Overall our results suggest that growth rate responds well to the application of family selection and carcass weight traits can also be improved in parallel, using this approach. Moreover, selection for high growth rate in GFP can be undertaken successfully before full market size has been reached. The outcome of this study was production of an improved culture strain of GFP for the Vietnamese culture industry that will be trialed in real farm production environments to confirm the genetic gains identified in the experimental stock improvement program.

Structural and electronic properties of diazonium functionalized (4, 4) single walled carbon nanotube : an ab initio study

In this work, ab initio density functional theory (DFT) calculations are performed to study the structural and electronic properties of diazonium reagent functionalized (4, 4) single-walled carbon nanotube (SWCNT). We find the aryl group covalently bonds with SWCNT and prefers to be perpendicular to the side wall of nanotube. It has a rotational barrier of 0.35 eV around the formed aryl-tube bond axis and should be thermodynamically stable at room temperature. Additionally, new peaks appeared around the Fermi energy in the density of state (DOS) due to the weak band dispersion. Increasing of the coverage of the functional group will result in significant upshift of the Fermi level.

Memory effect in the deposition of C20 fullerenes on a diamond surface

In this paper, the deposition of C-20 fullerenes on a diamond (001)-(2x1) surface and the fabrication of C-20 thin film at 100 K were investigated by a molecular dynamics (MD) simulation using the many-body Brenner bond order potential. First, we found that the collision dynamic of a single C-20 fullerene on a diamond surface was strongly dependent on its impact energy. Within the energy range 10-45 eV, the C-20 fullerene chemisorbed on the surface retained its free cage structure. This is consistent with the experimental observation, where it was called the memory effect in "C-20-type" films [P. Melion , Int. J. Mod. B 9, 339 (1995); P. Milani , Cluster Beam Synthesis of Nanostructured Materials (Springer, Berlin, 1999)]. Next, more than one hundred C-20 (10-25 eV) were deposited one after the other onto the surface. The initial growth stage of C-20 thin film was observed to be in the three-dimensional island mode. The randomly deposited C-20 fullerenes stacked on diamond surface and acted as building blocks forming a polymerlike structure. The assembled film was also highly porous due to cluster-cluster interaction. The bond angle distribution and the neighbor-atom-number distribution of the film presented a well-defined local order, which is of sp(3) hybridization character, the same as that of a free C-20 cage. These simulation results are again in good agreement with the experimental observation. Finally, the deposited C-20 film showed high stability even when the temperature was raised up to 1500 K.

An isoviscous, isothermal model investigating the influence of hydrostatic recesses on a spring-supported tilting pad thrust bearing

Tilting-pad hydrodynamic thrust bearings are used in hydroelectric power stations around the world, reliably supporting turbines weighing hundreds of tonnes, over decades of service. Newer designs incorporate hydrostatic recesses machined into the sector-shaped pads to enhance oil film thickness at low rotational speeds. External pressurisation practically eliminates wear and enhances service life and reliability. It follows that older generating plants, lacking such assistance, stand to benefit from being retrofitted with hydrostatic lubrication systems. The design process is not trivial however. The need to increase the groove size to permit spontaneous lifting of the turbine under hydrostatic pressure, conflicts with the need to preserve performance of the original plane pad design. A haphazardly designed recess can induce a significant rise in bearing temperature concomitant with reduced mechanical efficiency and risk of thermal damage. In this work, a numerical study of a sector-shaped pad is undertaken to demonstrate how recess size and shape can affect the performance of a typical bearing.