Influence of Humic Acid on Water Quality and Growth of Algae in Freshwater Ecosystem

One of the approaches to improve aquaculture production is through improvement of fertilization program for phytoplankton production and water quality variables. There are serious problems with the use of raw organic fertilizer in ponds and environment. Oxygen depletion, degradation of water quality, reduced light penetration, and spread of diseases frequently occur after large doses of manure are added to a pond at irregular intervals. This study was conducted to investigate the influence of humic acid (HA) on primary productivity (phytoplankton production) and water quality variables in a freshwater aquatic ecosystem. Two experiments were carried out to evaluate effects of humic acid alone or in combination with inorganic (urea and single super phosphate) or organic fertilizer (cow manure) on the phytoplankton productivity. Prior to the experiments, HA contents of cow manure (CM), chicken manure, compost and tropical peat were estimated to determine the suitable source (quantity) for HA extraction. The results showed that tropical peat contained 46.5% (dry weight basis) HA and 11.6-17.2 folds higher than the other organic fertilizers. Humic acid from the tropical peat was used in the subsequent experiments. An experiment was conducted at the Gharehsoo Station of Fisheries Research Centre of Mazandaran (FRCM) in North of Islamic Republic Iran (July and August 1999) to study the effects of HA and inorganic fertilizer (urea and single super phosphate) on growth of selected freshwater phytoplankton and water quality variables. The experiment was carried out in eighteen 1.5 Liter transparent plastic bottles (control , 25 ppm HA+UP, 50 ppm HA+UP, 100 ppm HA, 100 ppm HA+UP, 150 ppm HA+UP). Three species of green algae (Chlorella vulgaria, Scenedesmus quadricauda, and Oocystis solitaria) and a species of blue-green alga (Oscillatoria agardii) were selected for the study. The results showed that highest population (bloom) was achieved in week 3 by 100 ppm HA. All treatments with a combination of HA and urea-phosphate led to a blue-green algal (Oscillatoria agardii) dominancy with a low phytoplankton bloom and low total nitrogen (TN) and total phosphorus (TP) ratio (0.7-1.03). The green algal dominance was associated with a high TN:TP ratio (16-17) in culture media. pH of HA treatment was within the suitable range (7.84-8.51) for phytoplankton production. Light penetration correlated well with blue-green algal populatio

Nutrient Optimization And Computerized Decision Support Program In Recirculating Integrated Aquaculture System

There are many research activities to improve sustainable aquaculture and agriculture production in the wide world. Sustainable aquaculture is referred to as production of aquatic commodities through farming activities with social, economic and environmental sustainability. A series of experiments were conducted to compare different inorganic and organic fertilizers to improve production of Macrobrachium rosenbergii and to make a decision support program in an artificial sustainable aquaculture-agriculture system. Simply, nutrient wastes from culture tanks were used to fertilize hydroponics or terrestrial plants production via irrigation water. The sustainability and success functioning of the whole system were involved to manage and optimize the use of supplemented minerals, diet and desirable environment for each compartment (prawn, plant and microorganisms).The first experiment was made to evaluate the tolerance of M. rosenbergii in different levels of inorganic fertilizer (EC) formulated in nutrient film technique (NFT) vegetable production system. Results of the first experiment indicated that desirable growth rate of M. rosenbergii was obtained using 0.1 to 0.5EC of supplemental liquid fertilizer. High concentration of potassium (117-177 mg l-1), ammonia (0.72-1.05 mg l-1) and copper (0.04-0.06 mg l-1) inhibited the growth rate of M. rosenbergii in integrated culture system. The second experiment was carried out to assess the effects of different nutrient and stocking density on different population of M. rosenbergii in polyculture system. A different range of inorganic and organic fertilizer was used in the polyculture of plant and freshwater prawn species. Overall results indicated that essential concentration of nutrients, source and M. rosenbergii stocking density have played a major role in the effectiveness of suitable range of minerals in integrated production system. The results also demonstrated that 0.5 EC liquid inorganic fertilizer was not suitable to provide optimum nutrients and chicken manure is still an important fertilizer even in indoor integrated culture system. Finally, a comparative study was conducted to evaluate the optimum level of chicken manure and formulated inorganic nutrients in an artificial integrated culture system. The results indicated that high density culture of M. rosenbergii juveniles (380-400 individual m-2) in fiberglass tanks is possible by the installation of artificial substrate and controlling of nutrient concentration in system. Moreover the addition of aeration tank significantly improved the quality of water (DO and pH) and freshwater prawn growth (1343.0 g/tank) in recirculated polyculture system. The application of 70 g m-3 chicken manure alone encouraged growth of benthic and periphyton algae in culture tanks. The overall observation illustrated the desirable combination of supplemental liquid fertilizer and chicken manure is essential to obtain best growth for each compartment in sustainable polyculture system. A visual expert program (IAAS) was adopted to improve managing and develop technical operation in an artificial integrated culture system. The operation of the polyculture system required the specific knowledge, developing and application of computer systems to excellent operation, control of water quality variables, dissolved nutrients and feed to avoid the production of toxic substance and increase self efficiency and sustainability of the culture system. The accuracy of IAAS expert program was evaluated by polynomial and linear regression techniques through additional experiment. The comparison of results (yield and survival) in expert and real culture system represents higher variation of survival, prawn and plant yields in abnormal culture system. Moreover the evaluation processes demonstrated succeed performance of IAAS expert program in prediction results of optimized integrated culture system (with low variation). In aquaculture, the success estimation of production depends largely on the state of physical and chemical parameters which define optimal culture conditions

Quantum state engineering in a cavity by Stark chirped rapid adiabatic passage

We propose a robust scheme to generate single-photon Fock states and atom-photon and atom-atom entanglement in atom-cavity systems. We also present a scheme for quantum networking between two cavity nodes using an atomic channel. The mechanism is based on Stark-chirped rapid adiabatic passage (SCRAP) and half-SCRAP processes in a microwave cavity. The engineering of these states depends on the design of the adiabatic dynamics through the static and dynamic Stark shifts.Comment: 7 pages, 8 figures, to be appeared in PL

Primary culture of freshwater prawn (Macrobrachium rosenbergii) in an integrated hydrophonics nutrient film technique system (NFT): nutrient deficiency and toxicity

The aim of this study was to evaluate the tolerance of Macrobrachium rosenbergii, and plant to different levels of inorganic fertilizer in an artificial integrated production system. The growth comparison of lettuce and Chinese cabbage in different culture media illustrated that Chinese cabbage is more sensitive to nutrient deficiency and lettuce performed better growth (quality and quantity) compared to the Chinese cabbage in lower concentration of nutrients. In this study, 0.1 EC culture media showed better performance in M. rosenbergii production followed by 0.5 EC treatment. The overall results illustrated that potassium (P), ammonia (NH3) and copper (Cu) toxicities inhibited growth of freshwater prawn (M. rosenbergii) in high level supplemental chemical fertilizer (>0.5 EC mS/cm). Meanwhile, the sufficient quantities of some essential nutrients for lettuce and Chinese cabbage can not be obtained from wastewater of prawn culture system

Computerized visual assessment and validation technique in an Integrated Agriculture-Aquaculture System (IAAS)

Laboratory and artificial models are the acceptable way to find and explore the relationship among various compartments in an integrated system which combine many variables and practical results in the same or different condition. The purpose of this study is to improve the available visual IAAS (Integrated Agriculture-Aquaculture System) program for evaluation of freshwater prawn (Macrobrachium rosenbergii) and plant (Lactuca sativa) yields. Available data on Macro brachium rosenbergii yields, survival, nutrient concentration and plant production were compared to the predicted results by IAAS expert program. Results represent higher variation of survival, prawn and plant yields in abnormal culture system. Moreover the evaluation process demonstrated a good performance of IAAS expert program in predicting results for the optimized integrated culture system. In aquaculture, the success estimation of production depends largely on the state of physical and chemical parameters which define optimal culture conditions

Low-energy neutron irradiation on Bi-based (2223) Ag superconductors

 Bi-based and Ag-doped superconductors were irradiated by neutrons. Experimental result showed that XRD patern-intensity of irradiated Bi-based sample was decreased and The Tc of these samples were decreased by 7-10 K. The neutron irradiated sample was also found to decrease by 50% the normal state resistivity of samples. Therefore, neutron irradiation is a useful method to improve the superconductivity behavior of Bi-based materials

Influences of Sr-90 beta-ray irradiation on electrical characteristics of carbon nanoparticles

This work is concerned with the low cost fabrication of carbon nanoparticles (CNPs), and its application to beta ray detection. The structural and morphological properties of the CNPs were obtained by spectral and microscopy techniques. A system based on CNPs application in the metal-semiconductor-metal (MSM) junction platform, which acts as a beta-ray (β-ray) sensor, is fabricated. The prototype is characterised by modelling, Monte Carlo simulation, and electrical investigations. Changes to the electrical behaviour of the proposed MSM system due to β-ray irradiation are validated by experimental results in both Ohmic and non-Ohmic (Schottky) contacts. The simulation was performed using the MCNPX code, which showed that most of the β-ray energies are deposited into CNPs and electrodes. However, in the Ohmic contact, because the β-ray is induced, the current of CNPs is decreased. The reduction of the current might be due to the change of the carrier properties by increasing the scattering of electrons. The current-density equation for electrons was employed for understanding the effects of β-ray in Ohmic contact of CNPs. On the contrary, in the Schottky contact case, CNPs current was increased with constant voltage when biased by β-ray irradiation. In this paper, the electron-hole generation using β-rays is dominant when compared to other significant effects of radiation exposure on semiconducting CNP-based Schottky contact. Hence, the current increment of CNPs can be justified by electron-hole generation in the depletion region