An intrinsic biochemical concentration sensor using a polymer optical fibre Bragg grating

A new type of fibre-optic biochemical concentration sensor based on a polymer optical fibre Bragg grating (POFBG) is proposed. The wavelength of the POFBG varies as a function of analyte concentration. The feasibility of this sensing concept is demonstrated by a saline concentration sensor. When polymer fibre is placed in a water based solution the process of osmosis takes place in this water-fibre system. An osmotic pressure which is proportional to the solution concentration, will apply to the fibre in addition to the hydraulic pressure. It tends to drive the water content out of the fibre and into the surrounding solution. When the surrounding solution concentration increases the osmotic pressure increases to drive the water content out of the fibre, consequently increasing the differential hydraulic pressure and reducing the POFBG wavelength. This process will stop once there is a balance between the osmotic pressure and the differential hydraulic pressure. Similarly when the solution concentration decreases the osmotic pressure decreases, leading to a dominant differential hydraulic pressure which drives the water into the fibre till a new pressure balance is established. Therefore the water content in the polymer fibre - and consequently the POFBG wavelength - depends directly on the solution concentration. A POFBG wavelength change of 0.9 nm was measured for saline concentration varying from 0 to 22%. For a wavelength interrogation system with a resolution of 1 pm, a measurement of solution concentration of 0.03% can be expected.

An intrinsic biochemical concentration sensor using a polymer optical fibre Bragg grating

A new type of fibre-optic biochemical concentration sensor based on a polymer optical fibre Bragg grating (POFBG) is proposed. The wavelength of the POFBG varies as a function of analyte concentration. The feasibility of this sensing concept is demonstrated by a saline concentration sensor. When polymer fibre is placed in a water based solution the process of osmosis takes place in this water-fibre system. An osmotic pressure which is proportional to the solution concentration, will apply to the fibre in addition to the hydraulic pressure. It tends to drive the water content out of the fibre and into the surrounding solution. When the surrounding solution concentration increases the osmotic pressure increases to drive the water content out of the fibre, consequently increasing the differential hydraulic pressure and reducing the POFBG wavelength. This process will stop once there is a balance between the osmotic pressure and the differential hydraulic pressure. Similarly when the solution concentration decreases the osmotic pressure decreases, leading to a dominant differential hydraulic pressure which drives the water into the fibre till a new pressure balance is established. Therefore the water content in the polymer fibre - and consequently the POFBG wavelength - depends directly on the solution concentration. A POFBG wavelength change of 0.9 nm was measured for saline concentration varying from 0 to 22%. For a wavelength interrogation system with a resolution of 1 pm, a measurement of solution concentration of 0.03% can be expected.

Electrostatic Interactions Between Glycosaminoglycan Molecules

The electrostatic interactions between nearest-neighbouring chondroitin sulfate glycosaminoglycan (CS-GAG) molecular chains are obtained on the bottle brush conformation of proteoglycan aggrecan based on an asymptotic solution of the Poisson-Boltzmann equation the CS-GAGs satisfy under the physiological conditions of articular cartilage. The present results show that the interactions are associated intimately with the minimum separation distance and mutual angle between the molecular chains themselves. Further analysis indicates that the electrostatic interactions are not only expressed to be purely exponential in separation distance and decrease with the increasing mutual angle but also dependent sensitively on the saline concentration in the electrolyte solution within the tissue, which is in agreement with the existed relevant conclusions.

Effect of different salinity levels on the fertilization and hatching of Heterobranchus bidorsalis

The success of induced spawning for the production of fish seed depends on many factors which affect hatchery conditions. This paper discusses the results of an investigation on the effects of six different levels of salinity on the fertilization and hatching of Heterobranchus bidorsalis eggs. The results indicate that spermatozoa of H. bidorsalis can survive under a wide range of saline concentrations, with survival increasing with an increase in salinity from 0 to 0.4% and then decreasing as the level of salinity increases. Survival was optimum of 0.4% saline concentration.

Estado nutricional e componentes da produção de plantas de pimentão conduzidas em sistema de fertirrigação durante indução de estresse salino em cultivo protegido

O uso das técnicas de fertirrigação em ambiente protegido vem aumentando no Brasil devido à praticidade de condução e redução dos custos de produção. Apesar dessas vantagens, salienta-se que esta prática também pode trazer riscos, principalmente pelo acúmulo de sais na superfície do solo e na região periférica do bulbo radicular. em caso de salinização do solo pelo manejo incorreto do sistema podem ocorrer alterações na disponibilidade de nutrientes, com conseqüências fisiológicas no desenvolvimento das plantas. Neste trabalho, utilizou-se o pimentão (Capsicum annuum L.) como planta-modelo para estudos da interferência da salinidade na nutrição das plantas, pela alteração da condutividade elétrica (CE) na solução do solo. Os resultados revelaram indícios de antagonismo entre nutrientes, notadamente entre as formas catiônicas em razão do aumento da concentração de KCl nos tratamentos com alta CE. A suplementação do solo com adubo orgânico não atenuou os efeitos do aumento da concentração salina e os valores extremos de CE interferiram drasticamente na produção.

Water osmotic absorption in Coleus blumei plants under salinity stress

Mudas envasadas de Coleus blumei, com três meses de idade, foram submetidas a diferentes concentrações de cloreto de sódio (NaCl: 0,00; 0,25; 0,50 e 1,00%). Visando determinar a absorção osmótica, as mudas tiveram seus caules cortados a 10 cm acima do solo. Os caules remanescentes foram interligados a tubos de vidro por tubos flexíveis de borracha. Foram feitas leituras (cm) a cada 30 minutos dos níveis das colunas de água nos capilares, correspondentes às absorções osmóticas de água, sendo ao todo realizadas onze leituras. em outro momento, mudas de C. blumei, com a mesma idade das anteriores, receberam as mesmas concentrações de NaCl descritas anteriormente, e, ao ar livre, foram avaliadas em termos de transpiração e resistência estomática, usando-se para isto porômetro LI 1600. Usou-se delineamento em blocos casualizados, com cinco repetições, submetendo-se os dados à análise de variância e regressão polinomial. Verificou-se para todos os tratamentos aumento da absorção osmótica até três horas após a adição das soluções. A partir desse momento observou-se reversão da absorção osmótica proporcional ao aumento da concentração salina, sendo esse efeito mais pronunciado em 1,00 % de NaCl, o que reflete perdas crescentes de água pelas raízes. No controle a absorção osmótica apresentou comportamento crescente e linear com o passar do tempo. A transpiração foi proporcionalmente reduzida com o aumento da concentração salina.

Uso racional de nutrientes no cultivo hidropônico de amorperfeito

The objective of this work was to evaluate different concentrations of nutritional solution in the hydroponic cultivation of Viola x wittrockiana Gams. The experiment was conducted in DFT hydroponic system, in a completely randomized design with a 5×4 factorial scheme and five nutrient solution concentrations (50, 75, 100, 125 and 150%), four evaluation periods with three replications of three plants for each treatment. Plant height, root length, number of leaves, flowers and floral buttons; fresh and dry weight of shoot and root were determined. The results were submitted to variance analysis, Tukey's test for evaluation periods and regression analysis for nutrient solution. A decrease in the development of the shoot and root was observed with an increase of the number of cultivation days; the greatest number of floral buttons occurred in the third week of cultivation. A reduction in the plant height, root system length, the number of leaves and the fresh and dry weight of shoot was observed generally with the increase of nutrient solution concentration.

Produção de frutos de pimentão em diferentes concentrações salinas

An experiment with an Elisa hybrid sweet pepper (Capsicum annuum L) crop using fertirrigation system was carried out in greenhouse. The aim of this study was to evaluate the quantitative effects of an increasing soil saline concentration on the production. The saline concentration was changed by the variation of the KC1 and Ca 2NO 3 concentration in order to obtain high soil electrical conductivity (EC) values. Standard fertigation system (1.5 dS m -1) values were used as control parameters. Besides that, the possibility of saline stress attenuation by applying organic material into the soil was studied. It was observed that the EC levels used in the crop were inversely correlated to the fructification index and the fruit mean weight. Under the most severe treatment (6.0 dS m -1) the fruit mean weight was reduced up to 58% and the mean produced fiuit number per plant was also reduced up to 55%, when compared to the obtained results under controlled conditions. These results demonstrated that the EC variation in the soil solution had strong interference on th production parameters selected for the studies.

Estresse salino induzido em plantas de pimentão (Capsicum annuum L.) fertirrigadas e seus efeitos sobre a produtividade e parâmetros bioquímicos

Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA

Thermoregulatory consequences of salt loading in the lizard Pogona vitticeps

Previous research has demonstrated that dehydration increases the threshold temperature for panting and decreases the thermal preference of lizards. Conversely, it is unknown whether thermoregulatory responses such as shuttling and gaping are similarly influenced. Shuttling, as an active behavioural response, is considered one of the most effective thermoregulatory behaviours, whereas gaping has been proposed to be involved in preventing brain over-heating in lizards. In this study we examined the effect of salt loading, a proxy for increased plasma osmolality, on shuttling and gaping in Pogona vitticeps. Then, we determined the upper and lower escape ambient temperatures (UETa and LETa), the percentage of time spent gaping, the metabolic rate ((V) over dot(O2)), the evaporative water loss (EWL) during gaping and non-gaping intervals and the evaporative effectiveness (EWL/(V) over dot(O2)) of gaping. All experiments were performed under isotonic (154 mmol l(-1)) and hypertonic saline injections (625, 1250 or 2500 mmol l(-1)). Only the highest concentration of hypertonic saline altered the UETa and LETa, but this effect appeared to be the result of diminishing the animal's propensity to move, instead of any direct reduction in thermoregulatory set-points. Nevertheless, the percentage of time spent gaping was proportionally reduced according to the saline concentration; (V) over dot(O2) was also decreased after salt loading. Thermographic images revealed lower head than body surface temperatures during gaping; however this difference was inhibited after salt loading. Our data suggest that EWL/(V) over dot(O2) is raised during gaping, possibly contributing to an increase in heat transfer away from the lizard, and playing a role in head or brain cooling.

Corrosión inducida por contaminantes hidrosolubles en la intercara metal/pintura

El objetivo principal de este trabajo es profundizar en el conocimiento del fenómeno de la corrosión subpelicular inducida por contaminantes hidrosolubles en la intercara metal/pintura. La contaminación salina del substrato es una situación común en la práctica: la superficie metálica suele estar expuesta a atmósferas contaminadas antes de ser recubierta, limpieza previa del metal con abrasivos contaminados, etc. La eliminación total de estos contaminantes resulta muy difícil de conseguir incluso con las técnicas más sofisticadas de limpieza. Esta investigación se centra en la determinación del efecto de la naturaleza del contaminante y la naturaleza y espesor del recubrimiento en el proceso de corrosión subpelicular del acero. En la investigación se utilizaron dos barnices de naturaleza diferente: poliuretano y vinílico; y se aplicaron a tres espesores diferentes. Los contaminantes empleados en este trabajo fueron: NaCl, NH4C1, CaCl2, Na2S04, (NH4)2S04, NaN03, NH4N03, Ca(N03)2. Los ensayos se realizaron en una cámara de condensación de humedad permanente. Los tiempos de exposición fueron 100, 300 y 600 horas. La velocidad de corrosión se evaluó gravimétricamente, mediante la técnica de pérdida de peso. Se realizaron estudios de permeabilidad al oxígeno y al agua de películas libres de substrato, evaluación de la velocidad de corrosión de probetas sin pintar inmersas en soluciones salinas de los contaminantes seleccionados, conductividad de dichas soluciones salinas, solubilidad del oxígeno en las soluciones salinas, adherencia en seco y en húmedo a diferentes tiempos de exposición. Se aporta evidencia respecto al control ejercido en el proceso corrosivo por el oxígeno que permea a través de la película, mientras que la permeación de agua controla la pérdida de adherencia del recubrimiento. Ambas permeabilidades dependen de la naturaleza del recubrimiento y de su espesor. Se ha investigado la influencia de la naturaleza del contaminante en la intercara metal/pintura. La naturaleza del catión parece quedar enmascarada por el efecto definitivo del anión. La concentración salina ejerce asimismo un efecto importante en la corrosión subpelicular. ABSTRACT The main aim of this work is to study in depth the knowledge of underfilm corrosión induced by hydrosoluble contaminants at the metal/paint Ínterface. The saline contamination of the substrate is a common situation in practice: metallic surfaces use to be exposed to polluted atmospheres, previous cleaning of the metal with contaminated abrasives, etc. Total elimination of these contaminants is hard to obtain even with modern cleaning techniques. This research is focused in determining the effect of contaminant nature, coating nature and its thickness on the steel underfilm corrosión process. In this work we used two varnishes with different nature: polyurethane and vinyl; they were applied in three different thicknesses. The saline contaminants employed were: NaCl, NH4C1, CaCl2, Na2S04, (NH4)2S04, NaN03, NH4N03/ Ca(N03)2. The tests were carried out in a condensation humidity chamber. The period of exposure were 100, 300 and 600 hours. Corrosión rate was assessed by weight loss. Simultaneously, studies on oxygen and water permeability of free films, assessing on corrosión rate of uncoated samples immersed in saline solutions of the selected contaminants, conductivity of these solutions, oxygen solubility in saline solutions, wet and dry adhesión of the polyurethane varnish at different periods of exposure, were carried out. There is clear evidence about control on corrosión process of oxygen that passes through the coating, while the passing of water controls the loss of adhesión of the coating. Both, water and oxygen permeation, depend on the nature and thickness of the coating. It has been researched the inf luence of the nature of contaminant at the metal/paint interface. The nature of the catión seems to be "masked" by the definitive effect of the nature of anión. The saline concentration also exerts an important effect on underfilm corrosión.

Ion exchange treatment of saline solutions using lanxess S108H strong acid cation resin

Common to many types of water and wastewater is the presence of sodium ions which can be removed by desalination technologies, such as reverse osmosis and ion exchange. The focus of this investigation was ion exchange as it potentially offered several advantages compared to competing methods. The equilibrium and column behaviour of a strong acid cation (SAC) resin was examined for the removal of sodium ions from aqueous sodium chloride solutions of varying normality as well as a coal seam gas water sample. The influence of the bottle-point method to generate the sorption isotherms was evaluated and data interpreted with the Langmuir Vageler, Competitive Langmuir, Freundlich, and Dubinin-Astakhov models. With the constant concentration bottle point method, the predicted maximum exchange levels of sodium ions on the resin ranged from 61.7 to 67.5 g Na/kg resin. The general trend was that the lower the initial concentration of sodium ions in the solution, the lower the maximum capacity of the resin for sodium ions. In contrast, the constant mass bottle point method was found to be problematic in that the isotherm profiles may not be complete, if experimental parameters were not chosen carefully. Column studies supported the observations of the equilibrium studies, with maximum sodium loading of ca. 62.9 g Na/kg resin measured, which was in excellent agreement with the predictions of the data from the constant concentration bottle point method. Equilibria involving coal seam gas water were more complex due to the presence of sodium bicarbonate in solution, albeit the maximum loading capacity for sodium ions was in agreement with the results from the more simple sodium chloride solutions.

Saline water intrusion from deep artesian sources in McGregor Isles area of Lee County, Florida

Upward leakage of saline water from an artesian aquifer below 1,500 feet has caused an increase in chloride concentration in the lower Hawthorn aquifer from less than 1,000 mg/1 (milligrams per liter) to values ranging from about 1,300 to 15,000 mg/1. Similarly the higher temperatures of the intruding water has caused an increase in water temperatures in the aquifer from 82"F to values ranging from 83 to 93"F. The intruding water moves upward either through the open bore hole of deep wells or test holes, or along a fault or fracture system, which has been identified in the area. From these points of entry into the lower Hawthorn aquifer, the saline water spreads laterally toward the south and southeast, but is generally confined to components of the fault system. The saline water moves upward from the lower Hawthorn aquifer into the upper Hawthorn aquifer through the open bore hole of wells, which connect the aquifers. This movement has resulted in an increase in chloride from less than 200 mg/1 in the unaffected parts of the upper Hawthorn aquifer to values commonly ranging from about 300 to more than 3,000 mg/1 in parts of the aquifer affected by upward leakage. The upper Hawthorn aquifer is the principal source of ground-water supply for public water-supply systems in western Lee County. Similar effects have been noted in the water-table aquifer, where chloride increased from less than 100 to concentrations ranging from about 500 to more than 5,000 mg/1. This was caused by the downward infiltration of water discharged at land surface from wells tapping the lower Hawthorn aquifer. The spread of saline water throughout most of the McGregor Isles area is continuing as of 1971. (40 page document)

Microbial use of organic substrates and maize growth, especially in saline and alkaline soils of Pakistani Punjab

This thesis consists of 4 main parts: (1) impact of growing maize on the decomposition of incorporated fresh alfalfa residues, (2) relationships between soil biological and other soil properties in saline and alkaline arable soils from the Pakistani Punjab, (3) decomposition of compost and plant residues in Pakistani soils along a gradient in salinity, and (4) interactions of compost and triple superphosphate on the growth of maize in a saline Pakistani soil. These 4 chapters are framed by a General Introduction and a Conclusions section. (1) In the first study, the effects of growing maize plants on the microbial decomposition of freshly chopped alfalfa residues was investigated in a 90-day pot experiment using a sandy arable soil. Assuming that the addition of alfalfa residues did not affect the decomposition of native soil organic matter, only 27% of the alfalfa residues were found as CO2. This suggests that a considerable part of alfalfa-C remained undecomposed in the soil. However, only 6% of the alfalfa residues could be recovered as plant remains in treatment with solely alfalfa residues. Based on d13C values, it was calculated that plant remains in treatment maize + alfalfa residues contained 14.7% alfalfa residues and 85.3% maize root remains. This means 60% more alfalfa-C was recovered in this treatment. (2) In the second study, the interactions between soil physical, soil chemical and soil biological properties were analysed in 30 Pakistani soils from alkaline and saline arable sites differing strongly in salinisation and in soil pH. The soil biological properties were differentiated into indices for microbial activity, microbial biomass, and community structure with the aim of assessing their potential as soil fertility indices. (3) In the third study, 3 organic amendments (compost, maize straw and pea straw) were added to 5 Pakistani soils from a gradient in salinity. Although salinity has depressive effects on microbial biomass C, biomass N, biomass P, and ergosterol, the clear gradient according to the soil salt concentration was not reflected by the soil microbial properties. The addition of the 3 organic amendments always increased the contents of the microbial indices analysed. The amendment-induced increase was especially strong for microbial biomass P and reflected the total P content of the added substrates. (4) The fourth study was greenhouse pot experiment with different combinations of compost and triple superphosphate amendments to investigate the interactions between plant growth, microbial biomass formation and compost decomposition in a strongly saline Pakistani arable soil in comparison to a non-saline German arable soil. The Pakistani soil had a 2 times lower content of ergosterol, a 4 times lower contents of microbial biomass C, biomass N and biomass P, but nearly a 20 times lower content of NaHCO3 extractable P. The addition of 1% compost always had positive effects on the microbial properties and also on the content of NaHCO3 extractable P. The addition of superphosphate induced a strong and similar absolute increase in microbial biomass P in both soils.

TiO(2)-PHOTOCATALYZED DEGRADATION OF PHENOL IN SALINE MEDIA IN AN ANNULAR REACTOR: HYDRODYNAMICS, LUMPED KINETICS, INTERMEDIATES, AND ACUTE TOXICITY

The photocatalytic degradation of phenol in aqueous suspensions of TiO(2) under different salt concentrations in an annular reactor has been investigated. In all cases, complete removal of phenol and mineralization degrees above 90% were achieved. The reactor operational parameters were optimized and its hydrodynamics characterized in order to couple mass balance equations with kinetic ones. The photodegradation of the organics followed a Langmuir-Hinshelwood-Hougen- Watson lumped kinetics. From GC/MS analyses, several intermediates formed during oxidation have been identified. The main ones were catechol, hydroquinone, and 3-phenyl-2-propenal, in this order. The formation of negligible concentrations of 4-chlorophenol was observed only in high salinity medium. Acute toxicity was determined by using Artemia sp. as the test organism, which indicated that intermediate products were all less toxic than phenol and a significant abatement of the overall toxicity was accomplished, regardless of the salt concentration.