scholarly journals Simulation of nonhomogeneous degradation process in the system with gradual and instantaneous failures

2018 ◽  
pp. 3 ◽  
Author(s):  
Александра Валентиновна Бородина ◽  
Виталий Анатольевич Тищенко ◽  
Alexandra Borodina ◽  
Vitalii Tishenko
Keyword(s):  
Degradation Process ◽  
Instantaneous Failures

Techniques For The Preparation of Tissue Samples Containing Injectable Polymer Microcapsules

1985 ◽  
Vol 43 ◽  
pp. 710-711
Author(s):  
G.E. Visscher ◽  
R. L. Robison ◽  
G. J. Argentieri
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Gastrocnemius Muscle ◽  
Degradation Process ◽  
Delivery Systems ◽  
Tissue Reaction ◽  
Electron Microscopic ◽  
Tissue Samples ◽  
Injectable Polymer ◽  
Microscopic Techniques

The use of various bioerodable polymers as drug delivery systems has gained considerable interest in recent years. Among some of the shapes used as delivery systems are films, rods and microcapsules. The work presented here will deal with the techniques we have utilized for the analysis of the tissue reaction to and actual biodegradation of injectable microcapsules. This work has utilized light microscopic (LM), transmission (TEM) and scanning (SEM) electron microscopic techniques. The design of our studies has utilized methodology that would; 1. best characterize the actual degradation process without artifacts introduced by fixation procedures and 2. allow for reproducible results.In our studies, the gastrocnemius muscle of the rat was chosen as the injection site. Prior to the injection of microcapsules the skin above the sites was shaved and tattooed for later recognition and recovery. 1.0 cc syringes were loaded with the desired quantity of microcapsules and the vehicle (0.5% hydroxypropylmethycellulose) drawn up. The syringes were agitated to suspend the microcapsules in the injection vehicle.

Anaerobic Semi-Continuous Culture Biodegradation of Dichlorophenols Containing an Ortho Chlorine

1987 ◽  
Vol 22 (3) ◽  
pp. 427-436 ◽  
Author(s):  
S.E. Hrudey ◽  
E. Knettig ◽  
P.M. Fedorak ◽  
S.A. Daignault
Keyword(s):  
Activated Carbon ◽  
Continuous Culture ◽  
Chlorine Atom ◽  
Degradation Process ◽  
Anaerobic Sludge ◽  
Continuous Cultures ◽  
Complete Mineralization

Abstract Rapid and preferential dechlorination of the ortho chlorine from 2,6-, 2,4- and 2,3- dichlorophenol substrates was observed in semi-continuous cultures inoculated with 50% unacclimated anaerobic sludge. The rate of further dechlorination depended on the position of the second chlorine atom. The dechlorination rates for the second chlorine ranked ortho > para > meta. Complete mineralization to methane was only observed in cultures fed 2,6-dichlorophenol. Addition of activated carbon to the anaerobic cultures showed some benefit to the degradation process.

Examination for Degradation Paths of Butyltin Compounds in Natural Waters

1992 ◽  
Vol 25 (11) ◽  
pp. 117-124 ◽  
Author(s):  
N. Watanabe ◽  
S. Sakai ◽  
H. Takatsuki
Keyword(s):  
Glass Fiber ◽  
Half Life ◽  
Natural Waters ◽  
Sea Water ◽  
Degradation Process ◽  
Distilled Water ◽  
Degradation Rates ◽  
Clean Area ◽  
Butyltin Compounds ◽  
Sun Light

Examination of individual degradation paths (biodegradation and photolysis) of butyltin compounds (especially tributyltin: TBT) in natural waters was performed. Biodegradation of TBT and dibutyltin (DBT) in an unfiltered sea water in summer is rather fast; their half life is about a week. But pretreatment with glass fiber filter makes the half life of TBT much longer (about 80 days). Photolysis of TBT in sea water by sun light is rapid (half life is about 0.5 days), and faster than in distilled water or in fresh water. Degradation rates of each process for TBT are calculated in various conditions of sea water, and contribution rates are compared. Biodegradation will be the main degradation process in an “SS-rich” area such as a marina, but photolysis will exceed that in a “clean” area. Over all half lives of TBT in sea water vary from 6 days to 127 days considering seasons and presence of SS.

Surface charge and extracellular polymer of sludge in the anaerobic degradation process

1996 ◽  
Vol 34 (5-6) ◽  
pp. 309-316 ◽  
Author(s):  
X. S. Jia ◽  
Herbert H. P. Fang ◽  
H. Furumai
Keyword(s):  
Surface Charge ◽  
Growth Phase ◽  
Anaerobic Degradation ◽  
Degradation Process ◽  
Anaerobic Sludge ◽  
Batch Experiments ◽  
High Substrate Concentration ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Extracellular Polymer

Changes of surface charge and extracellular polymer (ECP) content were investigated in batch experiments for three anaerobic sludges, each of which had been enriched at 35°C and pH 639-7.3 for more than 40 batches using propionate, butyrate and glucose, individually, as the sole substrate. Results showed that both ECP and the negative surface charge were dependent on the growth phase of microorganisms. They increased at the beginning of all batches when the microorganisms were in the prolific-growth phase, having high substrate concentration and food-to-microorganisms ratio. Both later gradually returned to their initial levels when the microorganisms were in the declined-growth phase, as the substrate became depleted. The negative surface charge increased linearly with the total-ECP content in all series with slopes of 0.0187, 0.0212 and 0.0157 meq/mg-total-ECP for sludge degrading propionate, butyrate and glucose, respectively. The change of surface charge for the first two sludges was mainly due to the increase of proteinaceous fraction of ECP; but, for glucose-degrading sludge, that could be due to the increases of both proteinaceous and carbohydrate fractions of ECP. The negative-charged nature of anaerobic sludge implies that cations should be able to promote granulation of anaerobic sludge.

STRUCTURAL EVALUATION METHOD OF TRANSVERSE JOINT OF CONCRETE PAVEMENT CONSIDERING DEGRADATION PROCESS

2018 ◽  
Vol 74 (2) ◽  
pp. 42-51
Author(s):  
Tatsuo NISHIZAWA ◽  
Yuya WAKABAYASHI ◽  
Masataka UCHIDA ◽  
Masayuki YABU
Keyword(s):  
Evaluation Method ◽  
Degradation Process ◽  
Concrete Pavement ◽  
Structural Evaluation ◽  
Transverse Joint

SOLOS FRÁGEIS DO PARQUE NACIONAL DA SERRA DA CAPIVARA, PIAUÍ

GEOgraphia ◽  
2018 ◽  
Vol 19 (41) ◽  
pp. 123
Author(s):  
Gustavo Souza Valladares ◽  
Cláudia Maria Sabóia de Aquino ◽  
Renê Pedro de Aquino ◽  
Raphael Moreira Beirigo
Keyword(s):  
Soil Conservation ◽  
National Park ◽  
Soil Classification ◽  
Degradation Process ◽  
Archaeological Sites ◽  
Small Depth ◽  
Palabras Clave ◽  
Low Degree ◽  
Chemical Attributes ◽  
Pelitic Rocks

Resumo: O Parque Nacional da Serra da Capivara (PNSC) tem alguns dos sítios arqueológicos mais importantes das Américas. A área onde os solos foram amostrados corresponde ao Parque Nacional da Serra da Capivara (PNSC) e uma área tampão de 10km no entorno de seus limites oficiais, no sudeste do Piauí. Para a elaboração do presente trabalho foram selecionados solos considerados frágeis, devido ao alto risco de degradação por erosão, formados de diferentes materiais geológicos representativos do PNSC. Todos os solos estudados são pouco evoluídos, com desenvolvimento pedogenético ainda incipiente, e enquadram-se nas ordens dos Neossolos ou Cambissolos. O bioma representativo da área de estudo é a caatinga, que pela vegetação com pouca biomassa e características decíduas confere pouca cobertura aos solos, aumentando a susceptibilidade dos mesmos à erosão. Foram coletados sete perfis de solos, em diferentes posições na paisagem e formados de materiais de origem. As amostras foram secas ao ar e analisados atributos químicos e granulométricos. Os solos estudados apresentam grandes variações em seus atributos morfológicos, químicos e granulométricos, reflexo dos diferentes materiais de origem. A fragilidade em quase todos os perfis é reflexo da incipiência dos solos, representada pelo baixo grau de agregação e coesão entre as partículas, pequena profundidade e o fator de formação relevo induz na maior erosão de cinco dos sete perfis estudados. Os solos frágeis do PNSC necessitam de cuidados especiais quanto ao manejo, pois alguns deles, principalmente os originários de rochas pelíticas da Formação Pimenteiras, encontram-se em forte processo de degradação, em muitas áreas com as rochas expostas. Palavras-chave: Conservação do solo. Classificação de solos. Degradação ambiental. Semiárido tropical. FRAGILE SOILS OF SERRA DA CAPIVARA NATIONAL PARK, PIAUÍ Abstract: The Serra da Capivara National Park (PNSC) are some of the most important archaeological sites in the Americas. The area where the soils were sampled corresponds to the PNSC and a buffer area of 10km around of its official limits in southeastern of Piauí. For this work were considered fragile soils, due to the high risk of degradation by erosion, formed in different geological materials representative of PNSC. All soils are poorly evolved, with pedogenic development incipient fall in orders of Entisols or Inceptisols. The representative of the study area biome is the caatinga, which vegetation with little biomass and deciduous characteristics, gives little coverage to the soil, increasing susceptibility to erosion. Seven soil profiles were collected at different positions and mother rocks. The soils were classified according to the Brazilian System of Soil Classification (SiBCS). The samples were air dried and analyzed the chemical attributes and texture. The soils vary widely in their morphological, chemical and grain size, reflecting the different source material attributes. The weakness in nearly all profiles reflects the incipient soil, represented by a low degree of aggregation and cohesion between the particles of soil and small depth of relief factor induces the formation of further erosion profiles 5 of the 7 studied. Fragile soils of PNSC require special care in the mangement, because some soils, especially those originating from pelitic rocks by Pimenteiras Formation, are in strong degradation process in many areas with exposed rocks. Keywords: Soil conservation. Soil classification. Environmental degradation. Tropical semiarid. SUELOS FRÁGILES DEL PARQUE NACIONAL DE LA SIERRA DE CAPYBARA, PIAUÍ Resumen: El Parque Nacional de la Sierra de Capybara (PNSC) tiene algunos de los sitios arqueológicos más importantes de las Américas. El área donde los suelos fueron muestreados corresponde al PNSC y un área tampón de 10km en el entorno de sus límites oficiales, en el sureste del Piauí. Para la elaboración del presente trabajo se seleccionaron suelos considerados frágiles, debido al alto riesgo de degradación por erosión, formados de diferentes materiales geológicos representativos del PNSC. Todos los suelos estudiados son poco evolucionados, con desarrollo pedogenético aún incipiente, y se encuadran en las órdenes de los Neossolos o Cambissolos (en portugués). El bioma representativo del área de estudio es la caatinga, que por la vegetación con poca biomasa y características deciduas, confiere poca cobertura a los suelos, aumentando la susceptibilidad de los mismos a la erosión. Se recogieron muestras de siete perfiles de suelos, en diferentes posiciones en el paisaje y formados de materiales geológicos distintos. Las muestras fueron secas al aire y analizados los atributos químicos y granulométricos. Los suelos estudiados presentan grandes variaciones en sus atributos morfológicos, químicos y granulométricos, reflejo de los diferentes materiales de origen. La fragilidad en casi todos los perfiles es reflejo de la incipiente de los suelos, representada por el bajo grado de agregación y cohesión entre las partículas, pequeña profundidad y el factor de formación relieve induce en la mayor erosión de cinco de los siete perfiles estudiados. Los suelos frágiles del PNSC necesitan cuidados especiales en cuanto al manejo, pues algunos de ellos, principalmente los originarios de rocas pelíticas de la Formación Pimenteiras, se encuentran en fuerte proceso de degradación, en muchas áreas con las rocas expuestas. Palabras clave: Conservación del suelo. Clasificación de suelos. Degradación ambiental. Semiárido tropical.

Resistance to Synthetic Seawater Aggression of Clay Ceramics Incorporated with an Ornamental Stone Residue

2014 ◽  
Vol 798-799 ◽  
pp. 269-274 ◽  
Author(s):  
Gustavo de Castro Xavier ◽  
Jonas Alexandre ◽  
Paulo César de Almeida Maia ◽  
Fernando Saboya Albuquerque ◽  
Leonardo Gonçalves Pedroti ◽  
...  
Keyword(s):  
Firing Temperature ◽  
Standard Procedure ◽  
Degradation Process ◽  
Ceramic Materials ◽  
Linear Shrinkage ◽  
Synthetic Seawater ◽  
Internal Expansion ◽  
Ornamental Stone ◽  
Clay Ceramics ◽  
Chloride Salts

Clay ceramic materials exposed to a marine environment may be subjected to complete degradation due to the presence of chloride salts in the air. The exposition allows the chloride to penetrate in structural pores causing an internal expansion, which eventually split the ceramic apart. In open air, the solar radiation as well as the rain and wind contribute to accelerate the degradation process. In the present work the laboratory assisted degradation of clay ceramics incorporated with a granite residue from ornamental stone processing was evaluated by synthetic seawater aggression according to standard procedure. The amount of incorporated residues, up to 10 wt % and the ceramic firing temperature, up to 900°C, were variable conditions statistically analyzed by factorial planning. Degradation wetting-drying tests were conducted up to 6 months. The results showed that the linear shrinkage of the residue-free ceramics do not stabilize during the test period for any firing temperature. By contrast, the residue-incorporated ceramics tend to stabilize after 4 months. In addition, a decrease in water absorption and flexural strength was observed in same speciemens.

scholarly journals The Role of the Reactive Species Involved in the Photocatalytic Degradation of HDPE Microplastics Using C,N-TiO2 Powders

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 999 ◽  
Author(s):  
Aranza Denisse Vital-Grappin ◽  
Maria Camila Ariza-Tarazona ◽  
Valeria Montserrat Luna-Hernández ◽  
Juan Francisco Villarreal-Chiu ◽  
Juan Manuel Hernández-López ◽  
...  
Keyword(s):  
Wastewater Treatment Plants ◽  
Reaction System ◽  
Terrestrial Ecosystems ◽  
Degradation Process ◽  
Reactive Species ◽  
Hazardous Substances ◽  
Wide Range ◽  
Degradation Behaviors ◽  
Environmentally Friendly Process

Microplastics (MPs) are distributed in a wide range of aquatic and terrestrial ecosystems throughout the planet. They are known to adsorb hazardous substances and can transfer them across the trophic web. To eliminate MPs pollution in an environmentally friendly process, we propose using a photocatalytic process that can easily be implemented in wastewater treatment plants (WWTPs). As photocatalysis involves the formation of reactive species such as holes (h+), electrons (e−), hydroxyl (OH●), and superoxide ion (O2●−) radicals, it is imperative to determine the role of those species in the degradation process to design an effective photocatalytic system. However, for MPs, this information is limited in the literature. Therefore, we present such reactive species’ role in the degradation of high-density polyethylene (HDPE) MPs using C,N-TiO2. Tert-butanol, isopropyl alcohol (IPA), Tiron, and Cu(NO3)2 were confirmed as adequate OH●, h+, O2●− and e− scavengers. These results revealed for the first time that the formation of free OH● through the pathways involving the photogenerated e− plays an essential role in the MPs’ degradation. Furthermore, the degradation behaviors observed when h+ and O2●− were removed from the reaction system suggest that these species can also perform the initiating step of degradation.

scholarly journals Blind Deblurring Based on Sigmoid Function

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3484
Author(s):  
Shuhan Sun ◽  
Lizhen Duan ◽  
Zhiyong Xu ◽  
Jianlin Zhang
Keyword(s):  
Performance Optimization ◽  
Degradation Process ◽  
Image Deconvolution ◽  
Sigmoid Function ◽  
Blind Image Deblurring ◽  
Linear Estimators ◽  
Blind Deblurring ◽  
Degraded Image ◽  
Excellent Property ◽  
Blind Image

Blind image deblurring, also known as blind image deconvolution, is a long-standing challenge in the field of image processing and low-level vision. To restore a clear version of a severely degraded image, this paper proposes a blind deblurring algorithm based on the sigmoid function, which constructs novel blind deblurring estimators for both the original image and the degradation process by exploring the excellent property of sigmoid function and considering image derivative constraints. Owing to these symmetric and non-linear estimators of low computation complexity, high-quality images can be obtained by the algorithm. The algorithm is also extended to image sequences. The sigmoid function enables the proposed algorithm to achieve state-of-the-art performance in various scenarios, including natural, text, face, and low-illumination images. Furthermore, the method can be extended naturally to non-uniform deblurring. Quantitative and qualitative experimental evaluations indicate that the algorithm can remove the blur effect and improve the image quality of actual and simulated images. Finally, the use of sigmoid function provides a new approach to algorithm performance optimization in the field of image restoration.

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