Optimum zinc supplementation level in Nile tilapia Oreochromis niloticus juveniles diets

The present study was designed to determine the optimum dietary zinc supplementation to Nile tilapia juveniles (13.3 +/- 1.13 g), by using vegetable-based diets supplemented with increasing levels of zinc from commercial-grade zinc sulfate monohydrate, a previously determined zinc source of higher bioavailability. The basal diet was supplemented with 25, 50, 100, 150, 200, 300, or 400 mg/kg Zn. The experiment was conducted in forty 250-l tanks arranged in a recirculating water system. The experimental period was divided in two phases. For the first 10-week experimental phase, fish were fed satiation diets supplemented with increasing levels of zinc. For the second 5-week experimental phase, fish that were fed diets supplemented with 0-300 mg/kg Zn during the first phase were fed the 400 mg/kg Zn-supplemented diet; fish fed the diet supplemented with 400 mg/kg Zn (first phase) were fed the nonzinc-supplemented diet (second phase). Broken-line analysis showed that the optimum dietary zinc supplementation ((ZnSO4H2O)-H-.) to Nile tilapia juveniles, using weight gain and bone zinc saturation as response criteria, was 44.50 and 79.51 mg/kg Zn, respectively. When challenged by a zinc-deficient diet, tilapia mobilized stored bone zinc to preserve its zinc status. By considering that bone zinc saturation is a more accurate response criterion than weight gain, it was concluded that the optimum dietary zinc supplementation ((ZnSO4H2O)-H-.) in vegetable-based diets to Nile tilapia juveniles is 79.51 mg/kg Zn. (C) 2004 Elsevier B.V. All rights reserved.

Low-Level Fluoride Exposure Increases Insulin Sensitivity in Experimental Diabetes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Energy level decay and excited state absorption processes in dysprosium-doped fluoride glass

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of strong acids on red mud structural and fluoride adsorption properties

The removal of fluoride using red mud has been improved by acidifying red mud with hydrochloric, nitric and sulphuric acid. This investigation shows that the removal of fluoride using red mud is significantly improved if red mud is initially acidified. The acidification of red mud causes sodalite and cancrinite phases to dissociate, confirmed by the release of sodium and aluminium into solution as well as the disappearance of sodalite bands and peaks in infrared and X-ray diffraction data. The dissolution of these mineral phases increases the amount of available iron and aluminium oxide/hydroxide sites that are accessible for the adsorption of fluoride. The removal of fluoride is dependent on the charge of iron and aluminium oxide/hydroxides on the surface of red mud. Acidifying red mud with hydrochloric, nitric and sulphuric acid resulted in surface sites of the form ≡ SOH2+ and ≡ SOH. Optimum removal is obtained when the majority of surface sites are in the form ≡ SOH2+ as the substitution of a fluoride ion doesn’t cause a significant increase in pH. This investigation shows the importance of having a low and consistent pH for the removal of fluoride from aqueous solutions using red mud.

Optimum position of steel outrigger system for high rise composite buildings subjected to wind loads

The responses of composite buildings under wind loads clearly become more critical as the building becomes taller, less stiff and more lightweight. When the composite building increases in height, the stiffness of the structure becomes more important factor and introduction to belt truss and outrigger system is often used to provide sufficient lateral stiffness to the structure. Most of the research works to date is limited to reinforced concrete building with outrigger system of concrete structure, simple building plan layout, single height of a building, one direction wind and single level of outrigger arrangement. There is a scarcity in research works about the effective position of outrigger level on composite buildings under lateral wind loadings when the building plan layout, height and outrigger arrangement are varied. The aim of this paper is to determine the optimum location of steel belt and outrigger systems by using different arrangement of single and double level outrigger for different size, shape and height of composite building. In this study a comprehensive finite element modelling of composite building prototypes is carried out, with three different layouts (Rectangular, Octagonal and L shaped) and for three different storey (28, 42 and 57-storey). Models are analysed for dynamic cyclonic wind loads with various combination of steel belt and outrigger bracings. It is concluded that the effectiveness of the single and double level steel belt and outrigger bracing are varied based on their positions for different size, shape and height of composite building.

Optimum Evaluation of Reactive Power Requirements in Power Distribution-Systems

This paper presents three methodologies for determining optimum locations and magnitudes of reactive power compensation in power distribution systems. Method I and Method II are suitable for complex distribution systems with a combination of both radial and ring-main feeders and having different voltage levels. Method III is suitable for low-tension single voltage level radial feeders. Method I is based on an iterative scheme with successive powerflow analyses, with formulation and solution of the optimization problem using linear programming. Method II and Method III are essentially based on the steady state performance of distribution systems. These methods are simple to implement and yield satisfactory results comparable with the results of Method I. The proposed methods have been applied to a few distribution systems, and results obtained for two typical systems are presented for illustration purposes.

A low cost demagnetizer with controllable cycle and adjustable level

Demagnetization to zero remanent value or to a predetermined value is of interest to magnet manufacturers and material users. Conventional methods of demagnetization using a varying alternating demagnetizing field, under a damped oscillatory or conveyor system, result in either high cost for demagnetization or large power dissipation. A simple technique using thyristors is presented for demagnetizing the material. Power consumption is mainly in the first two half-cycles of applied voltage. Hence power dissipation is very much reduced. An optimum value calculation for a thyristor triggering angle for demagnetizing high coercive materials is also presented.

Optimum design of cantilever sheet pile walls in sandy soils using inverse reliability approach

In this paper an approach for obtaining depth and section modulus of the cantilever sheet pile wall using inverse reliability method is described. The proposed procedure employs inverse first order reliability method to obtain the design penetration depth and section modulus of the steel sheet pile wall in order that the reliability of the wall against failure modes must meet a desired level of safety. Sensitivity analysis is conducted to assess the effect of uncertainties in design parameters on the reliability of cantilever sheet pile walls. The analysis is performed by treating back fill soil properties, depth of the water table from the top of the sheet pile wall, yield strength of steel and section modulus of steel pile as random variables. Two limit states, viz., rotational and flexural failure of sheet pile wall are considered. The results using this approach are used to develop a set of reliability based design charts for different coefficients of variation of friction angle of the backfill (5%, 10% and 15%). System reliability considerations in terms of series and parallel systems are also studied.

Geochemistry of fluoride rich groundwater in Kolar and Tumkur Districts of Karnataka

Groundwater is a significant water resource in India for domestic, irrigation, and industrial needs. By far the most serious natural groundwater-quality problem in India, in terms of public health, derives from high fluoride, arsenic, and iron concentrations. Hydrogeochemical investigation of fluoride contaminated groundwater samples from Kolar and Tumkur Districts in Karnataka are undertaken to understand the quality and potability of groundwater from the study area, the level of fluoride contamination, the origin and geochemical mechanisms driving the fluoride enrichment. Majority of the groundwater samples did not meet the potable water criteria as they contained excess (>1.5 mg/L) fluoride, dissolved salts (>500 mg/L) and total hardness (75-924 mg/L). Hydrogeochemical facies of the groundwater samples suggest that rock weathering and evaporation-crystallization control the groundwater composition in the study area with 50-67% of samples belonging to the Ca-HCO3 type and the remaining falling into the mixed Ca-Na-HCO3 or Ca-Mg-Cl type. The saturation index values indicated that the groundwater in the study area is oversaturated with respect to calcite and under-saturated with respect to fluorite. The deficiency of calcium ion concentration in the groundwater from calcite precipitation favors fluorite dissolution leading to excess fluoride concentration.

Optimum aperture distributions in the presence of blockage

A method is presented for optimising the performance indices of aperture antennas in the presence of blockage. An N-dimensional objective function is formed for maximising the directivity factor of a circular aperture with blockage under sidelobe-level constraints, and is minimised using the simplex search method. Optimum aperture distributions are computed for a circular aperture with blockage of circular geometry that gives the maximum directivity factor under sidelobe-level constraints.

Optimum spacing for Cheby¿shev arrays

For a Cheby-bar shev array with a prescribed sidelobe level and given number of elements, an optimum spacing is shown to exist, for any arbitrarily prescribed steering angle, for which the beamwidth is the least obtainable. An expression for the optimum spacing is given.

Sensitivity of polyvinylidene fluoride films to mechanical vibration modes and impact after optimizing stretching conditions

The β-phase of polyvinylidene fluoride (PVDF) is well known for its piezoelectric properties. PVDF films have been developed using solvent cast method. The films thus produced are in α-phase. The α-phase is transformed to piezoelectric β-phase when the film is hot-stretched with various different stretching factors at various different temperatures. The films are then characterized in terms of their mechanical properties and surface morphological changes during the transformation from α- to β-phases by using X-ray diffraction, differential scanning calorimeter, Raman spectra, Infrared spectra, tensile testing, and scanning electron microscopy. The films showed increased crystallinity with stretching at temperature up to 80°C. The optimum conditions to achieve β-phase have been discussed in detail. The fabricated PVDF sensors have been tested for free vibration and impact on plate structure, and its response is compared with conventional piezoelectric wafer type sensor. The resonant and antiresonant peaks in the frequency response of PVDF sensor match well with that of lead zirconate titanate wafer sensors. Effective piezoelectric properties and the variations in the frequency response spectra due to free vibration and impact loading conditions are reported. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers.

Studies on the optimum protein to energy ratio of African catfish (Clarias batrachus Burchell)

A laboratory trial was conducted to determine the optimum dietary protein to energy (P/E) ratio of African catfish, Clarias gariepinus. The experiment was carried out in a flow-through system for 6 weeks. There were 12 treatments each with two replicates having 10 fish each with a mean initial weight of 1.80 ± 0.02g. Twelve semi-purified diets were formulated with four digestible crude protein levels (23, 26.5, 30 and 33.5%) and three digestible energy levels (2.25, 2.75 and 3.25 Kcal/g). The fish were fed three times daily at satiation level. The results of the study showed that, diet containing 33.5% digestible protein and 2.75 kcal/g digestible energy with a protein to energy ratio of 121 .8 (mg protein/kcal) appeared to be best utilized for growth.

Photoluminescence properties of LaF3: Eu3+ nanoparticles prepared by refluxing method

The europium-doped LaF3 nanoparticles were prepared by refluxing method in glycerol/water mixture and characterized with X-ray diffraction(XRD), field emission scanning electron microscopy(FE-SEM), UV-vis diffuse reflectance spectrum, and photoluminescence spectra. The results of XRD indicated that the obtained LaF3: Eu3+ nanoparticles were well crystallized with a hexagonal structure. ne FE-SEM image illustrated that the LaF3: Eu3+ nanoparticles were spherical with an average size around 30 nm. Under irradiation of UV light, the emission spectrum of LaF3: Eu3+ nanoparticles exhibited the characteristic line emissions arising front the D-5(0)-> F-7(J), (J=1, 2, 3, 4) transitions of the Eu3+ ions, with the dominating emission centered at 590 nm. In addition, the emissions from the 51), level could be clearly observed due to the low phonon energies (-350 cm(-1)) of LaF3 matrix. The optimum doping concentration for LaF3: Eu3+ nanoparticles was determined to be 20mol.%.

Specification of optimum holistic building environmental and energy performance information to support informed decision making

Political drivers such as the Kyoto protocol, the EU Energy Performance of Buildings Directive and the Energy end use and Services Directive have been implemented in response to an identified need for a reduction in human related CO2 emissions. Buildings account for a significant portion of global CO2 emissions, approximately 25-30%, and it is widely acknowledged by industry and research organisations that they operate inefficiently. In parallel, unsatisfactory indoor environmental conditions have proven to negatively impact occupant productivity. Legislative drivers and client education are seen as the key motivating factors for an improvement in the holistic environmental and energy performance of a building. A symbiotic relationship exists between building indoor environmental conditions and building energy consumption. However traditional Building Management Systems and Energy Management Systems treat these separately. Conventional performance analysis compares building energy consumption with a previously recorded value or with the consumption of a similar building and does not recognise the fact that all buildings are unique. Therefore what is required is a new framework which incorporates performance comparison against a theoretical building specific ideal benchmark. Traditionally Energy Managers, who work at the operational level of organisations with respect to building performance, do not have access to ideal performance benchmark information and as a result cannot optimally operate buildings. This thesis systematically defines Holistic Environmental and Energy Management and specifies the Scenario Modelling Technique which in turn uses an ideal performance benchmark. The holistic technique uses quantified expressions of building performance and by doing so enables the profiled Energy Manager to visualise his actions and the downstream consequences of his actions in the context of overall building operation. The Ideal Building Framework facilitates the use of this technique by acting as a Building Life Cycle (BLC) data repository through which ideal building performance benchmarks are systematically structured and stored in parallel with actual performance data. The Ideal Building Framework utilises transformed data in the form of the Ideal Set of Performance Objectives and Metrics which are capable of defining the performance of any building at any stage of the BLC. It is proposed that the union of Scenario Models for an individual building would result in a building specific Combination of Performance Metrics which would in turn be stored in the BLC data repository. The Ideal Data Set underpins the Ideal Set of Performance Objectives and Metrics and is the set of measurements required to monitor the performance of the Ideal Building. A Model View describes the unique building specific data relevant to a particular project stakeholder. The energy management data and information exchange requirements that underlie a Model View implementation are detailed and incorporate traditional and proposed energy management. This thesis also specifies the Model View Methodology which complements the Ideal Building Framework. The developed Model View and Rule Set methodology process utilises stakeholder specific rule sets to define stakeholder pertinent environmental and energy performance data. This generic process further enables each stakeholder to define the resolution of data desired. For example, basic, intermediate or detailed. The Model View methodology is applicable for all project stakeholders, each requiring its own customised rule set. Two rule sets are defined in detail, the Energy Manager rule set and the LEED Accreditor rule set. This particular measurement generation process accompanied by defined View would filter and expedite data access for all stakeholders involved in building performance. Information presentation is critical for effective use of the data provided by the Ideal Building Framework and the Energy Management View definition. The specifications for a customised Information Delivery Tool account for the established profile of Energy Managers and best practice user interface design. Components of the developed tool could also be used by Facility Managers working at the tactical and strategic levels of organisations. Informed decision making is made possible through specified decision assistance processes which incorporate the Scenario Modelling and Benchmarking techniques, the Ideal Building Framework, the Energy Manager Model View, the Information Delivery Tool and the established profile of Energy Managers. The Model View and Rule Set Methodology is effectively demonstrated on an appropriate mixed use existing ‘green’ building, the Environmental Research Institute at University College Cork, using the Energy Management and LEED rule sets. Informed Decision Making is also demonstrated using a prototype scenario for the demonstration building.