scholarly journals Limnological study of Serbian oxbow shaped Lake Srebrno, with special emphasis on the benthic community composition and structure

2013 ◽  
Vol 32 (1) ◽  
Author(s):  
Vesna Martinovic-Vitanovic ◽  
Snezana Ostojic ◽  
Natasa Popovic ◽  
Maja Rakovic ◽  
Vladimir Kalafatic
Keyword(s):  
Trophic Levels ◽  
Bottom Fauna ◽  
Class Iii ◽  
Composition And Structure ◽  
Medium Level ◽  
High Level ◽  
Physical And Chemical ◽  
Limnological Study

AbstractDetailed limnological study of the Lake Srebrno (Serbia) bottom fauna was performed in March 2007. Investigations included qualitative, quantitative, and saprobiological analysis of bottom fauna communities, physical and chemical analysis of sediments and determination of chlorophyll a concentration, as well as saprobic and trophic status analyses. Samples were collected at eighteen sites distributed along a shoreline and in deeper sections of the lake. Twenty taxa from nine macroinvertebrate groups were recorded. Family Chironomidae had the biggest index of participation, the highest species diversity and the largest density of populations in benthocenoses of Lake Srebrno. Faunistic similarity between sites was estimated according to Sorensen’s Quotient of Similarity (QS). The majority of benthocenoses - 56% showed a medium level of faunistic similarity (QS = 21-60%), and 42% of benthocenoses showed a high level of faunistic similarity (QS = 61-100%). The classification of Lake Srebrno based on saprobic and trophic levels was assessed. Saprobic level was in the range from alpha-meso- to poly-alpha-mesosaprobity. The water quality of the lake ranged from class III and between IV and III class. Generally, Lake Srebrno had eutrophic status with the gradation to hypertrophy.

scholarly journals Medidas de adesão entre agregado e ligante asfáltico

TRANSPORTES ◽  
2008 ◽  
Vol 16 (1) ◽  
Author(s):  
Kamilla Lima Vasconcelos ◽  
Amit Bhasin ◽  
Dallas N. Little ◽  
Jorge Barbosa Soares
Keyword(s):  
Chemical Interaction ◽  
Asphalt Binder ◽  
Fatigue Cracking ◽  
Adhesion Measurement ◽  
Materials Used ◽  
Enthalpy Of Immersion ◽  
Physical And Chemical ◽  
Energy Components

<p>A adesão entre agregado e ligante asfáltico vem sendo apontada como uma propriedade de grande importância para a causa de defeitos encontrados em pavimentos asfálticos, tais como trincas por fadiga, e dano por umidade. Diferentes mecanismos existem na literatura para explicar a adesão entre os dois materiais, porém, estes mecanismos podem ser resumidos em três grandes grupos: inter- travamento mecânico, adesão física, e interação química. A ocorrência de mais de um mecanismo simultaneamente parece ser o fenô- meno mais provável, sendo a relevância de cada um dependente das características físicas e químicas do agregado e do ligante asfálti- co. No presente trabalho, dois procedimentos foram utilizados para acessar a adesão entre agregado e ligante. O primeiro constou do cálculo do trabalho de adesão através da energia livre de superfície dos materiais envolvidos e o segundo, da determinação da entalpia de imersão quando soluções de asfalto são postas em contato com o agregado. Todos os materiais usados foram provenientes da biblio- teca de referência do SHRP sendo um pedregulho como agregado, e três diferentes ligantes asfálticos. Os resultados mostraram a capa- cidade do microcalorímetro em detectar possíveis interações químicas na adesão entre agregado e ligante asfáltico, em conjunto com adesão física. A presença de grupos funcionais mais fortemente adsorvidos pela superfície dos agregados justificou os maiores valores de entalpia de imersão para as combinações onde esses grupos se encontravam presentes.</p><p><em><strong>Abstract</strong> Adhesion between the asphalt binder and the aggregate is critical to the performance and durability of asphalt mixtures. According to the literature, distresses mechanisms such as fatigue cracking and moisture induced damage are correlated to the nature and quality of adhesion between these two materials. Different mechanisms already exist to explain adhesion, but they can be summa- rized in three main groups: mechanical interlocking, physical adhesion and chemical interaction. Although discussions of isolated theo- ries and mechanisms help to clarify the understanding of adhesion, they can rarely be separated completely to each other. The physical and chemical characteristics of asphalt and aggregate will in fact determine the relevance of each of these mechanisms. This study presents the results of two procedures for adhesion measurement: (i) an indirect method based on the surface free energy components of asphalt binder and aggregate; and (ii) the determination of the enthalpy of immersion through the use of a microcalorimeter. The materials used, a gravel as aggregate and three different neat asphalts, were provided by the Strategic Highway Research Program's Material Reference Library. The results showed the capacity of the microcalorimeter in detecting possible chemical reactions together with physical adhesion. The presence of functional groups more strongly adsorbed by the aggregate surface justified the higher values of the heat of immersion. </em></p>

scholarly journals Comparative Analysis of Gearboxes Wear in Excavators and Mining Trucks

2020 ◽  
Vol 174 ◽  
pp. 03017
Author(s):  
Andrey Kudrevatykh ◽  
Andrey Ashcheulov ◽  
Alena Ashcheulova ◽  
Kumis Urazbaeva
Keyword(s):  
Comparative Analysis ◽  
Mining Industry ◽  
Technical Condition ◽  
Used Oil ◽  
Dump Trucks ◽  
Wear Products ◽  
High Level ◽  
Physical And Chemical ◽  
Metallic Impurities

The primary task of all enterprises in mining industry is to increase the durability and reliability of the mining complex. These very indicators provide nonstop minerals mining, and as a result, productivity increases. Indicators maintaining at high level can be achieved by different ways, but the most effective method is repair-in-place diagnosis of the actual technical condition of the main units and assemblies of equipment, as it is less costly and the most informative. To identify gear malfunctions, the physical and chemical analysis of the used oil is used to determine metallic impurities. A comparative analysis of wear products accumulation in rotary gears of mining excavators and gearboxes of the motor-wheel of dump trucks revealed the similarity of mathematical models for the determination of metallic impurities in used oil. The “universal” mathematical model is given in the paper; it allows to determine the actual technical condition of gearboxes for various equipment with a few assumptions. Moreover, the model takes into account various indicators of the environment, used oil, as well as the operating parameters of the equipment.

scholarly journals The Study of the Drinking Water Quality from the Local Sources, Busu Village, Dolj County and of the Physical and Chemical Determinations

2018 ◽  
Vol 1 (1) ◽  
pp. 212-215
Author(s):  
Olimpia Pandia ◽  
Ion Sărăcin ◽  
Eliza Ștefania Tănasie
Keyword(s):  
Drinking Water ◽  
Chemistry Laboratory ◽  
Total Hardness ◽  
Limit Values ◽  
Chemical Indicators ◽  
Local Sources ◽  
Physical And Chemical ◽  
The Village

Abstract In the present paper, the authors refer to a study carried out in the village of Greceşti, Busu village, Dolj County, on the quality of drinking water from local sources (wells, wells and wells) and the comparison of these results with the limit values allowed by the legislation in force, namely Law 458/2002 and Law 311/2004, as well as the Water Framework Directive and the Groundwater Directive 118/2006 / EC. Organoleptic indicators, physical and chemical indicators from 10 distinct locations as source of harvested water were determined, where organoleptic indicators were determined by determination of taste and odour; physical indicators, determining the pH, colour, turbidity and total hardness; chemical indicators: ammonium, chlorides, oxidisability, nitrites. The determinations were made in the faculty’s agro-chemistry laboratory, using appropriate methods and equipment. Following the results, the causes leading to the results were established and a series of conclusions and recommendations were drafted.

scholarly journals Water Quality Analysis In Bengawan Solo River Bojonegoro Regency

2019 ◽  
Vol 11 (1) ◽  
pp. 1-9
Author(s):  
Dyah Setyaningrum ◽  
Laily Agustina R
Keyword(s):  
Water Quality ◽  
River Water ◽  
Quality Analysis ◽  
Water Sampling ◽  
Class Iii ◽  
Water Quality Analysis ◽  
Temperature Conductivity ◽  
Household Appliances

The purposeofthis research is to analyze the water quality of Bengawan Solo River in Bojonegoro Regency. Water sampling was carried out at 6 monitoring points along the Bengawan Solo River in Bojonegoro Regency. Determination of sampling monitoring points, based on the differences of characteristics that exist in the study area. Some parameters issued are temperature, conductivity, COD, BOD, and Oil/ fat food which are then compared with the criteria for Class III standards of river water quality in accordance with the Regional Regulation of East Java Province Number 2 of 2008. Based on the analysis results obtained at each point monitor, area 1, is the most polluted area. It is caused, in this area, there are several activity of downtown. Households produce waste from bathroom, toilet, kitchen, washing clothes and washing household appliances.

scholarly journals Diagnóstico da Qualidade do Leite Pasteurizado Distribuído pelo Programa do Leite na Microrregião do Seridó Oriental - RN

2015 ◽  
Vol 10 (2) ◽  
pp. 218-223
Author(s):  
J. K. B. Silva ◽  
R. A. Andrade ◽  
R. S. Falcão ◽  
R. P. Gusmão
Keyword(s):  
Chemical Analysis ◽  
Garbage Collection ◽  
Physical Space ◽  
Rio Grande ◽  
Pasteurized Milk ◽  
Milk Samples ◽  
Physico Chemical ◽  
Physical And Chemical

Neste trabalho foi avaliada a qualidade do leite pasteurizado distribuído pelo Programa do Leite na microrregião do Seridó Oriental do Rio Grande do Norte. Para a avaliação do leite, foram aplicadas listas de verificação nos pontos de coleta do município de Currais Novos em que foi observada insuficiência do espaço físico e da infraestrutura, ausência de espaço coberto para abrigar filas, ventilação, iluminação, sanitários, freezers, computador e telefone. Ainda, foi observado que não há dedetização e desratização periódicas do ambiente, higienização correta, acondicionamento adequado e coleta diária de lixo. Além disso, foram realizadas análises físico-químicas, que compreenderam a determinação de gordura, teste de alizarol, sólidos não gordurosos, acidez e índice crioscópico, de amostras do leite fornecido por 3 usinas de beneficiamento que fazem parte do programa. As listas de verificação apontaram resultados insatisfatórios quanto à dimensão e infraestrutura dos pontos de entrega. O percentual de amostras que se apresentaram fora dos padrões estabelecidos pela legislação para as análises físico-químicas de gordura, acidez e índice crioscópico foi, respectivamente, 87,5, 62,5 e 100%. Diagnostic of Quality of Pasteurized Milk Distributed by the Milk Program in the Micro Eastern Seridó – RN ABSTRACT - This work evaluated the quality of pasteurized milk delivered by the milk program in the micro eastern Served Rio Grande do Norte. For the evaluation of milk, checklists were applied at collection points in the municipality of New corrals where insufficient physical space and infrastructure, absence of covered rows to house, ventilation, lighting, plumbing, freezers, computer space was observed and phone. Still, it was observed that there is no periodic fumigation and pest control of the environment, proper sanitation, adequate storage and daily garbage collection. In addition, physical and chemical analyzes, which comprised the determination of fat, alizarol test, not fat solids, acidity and cryoscopic index of the milk samples provided by three beneficiation plants that are part of the program were conducted. The checklists showed unsatisfactory results regarding the size and infrastructure of delivery points. The percentage of samples that were outside of the standards established by law for the physico-chemical analysis of fat, acidity and cryoscopic index was, respectively, 87.5, 62.5 and 100%.

The structure and composition of macrozoobenthos community in varying water qualities in Kalibaru Waters, Bengkulu, Indonesia

2020 ◽  
Vol 22 (1) ◽  
Author(s):  
Lilisti LILISTI ◽  
Zamdial ZAMDIAL ◽  
Dede Hartono ◽  
Bieng Brata ◽  
Marulak Simarmata
Keyword(s):  
Human Activities ◽  
Aquatic Ecosystem ◽  
Chemical Parameters ◽  
Aquatic Life ◽  
Physical And Chemical Parameters ◽  
Ecological Threshold ◽  
Medium Level ◽  
The Government ◽  
Physical And Chemical

Abstract. Lilisti, Zamdial, Hartono D, Brata B, Simarmata M. 2021. The structure and composition of macrozoobenthos community in varying water qualities in Kalibaru Waters, Bengkulu, Indonesia. Biodiversitas 22: 106-112. Various human activities affect the quality of the aquatic ecosystem that can be assessed by measuring the physical, chemical, and biological parameters of the waters and sediments. This is the case of Kalibaru Waters, Bengkulu, Indonesia which shows changes in the estuary and marine ecosystems due to the cut-off of the main river around the area for the development of roads and bridges. The objective of this study was to analyze the quality of the waters and substrate, and the structure of the macrozoobenthos community as a bioindicator at the Kalibaru Waters. A survey was carried out in four stations, which was purposively selected based on human activities around the waters. Data collected included the physical and chemical parameters, and the diversity and density of macrozoobenthos species. The density of macrozoobenthos species was analyzed for summed dominance ratio (SDR), diversity (H'), homogeneity (E), and dominance (D) indices. The results showed that the physical and chemical parameters of Kalibaru Waters were acceptable for aquatic life, however, the oil contents at two stations exceeded the ecological threshold. Analysis of the macrozoobenthos community as a bioindicator for water quality found that the diversity and homogeneity indices were at a medium level indicating an unstable community, while the dominant index remained low indicating that none of the species was dominant in the Kalibaru Waters. This information is needed as a reference for the government of Bengkulu Province to make appropriate policies and management decisions to maintain the quality of the aquatic ecosystem in Kalibaru Waters.

scholarly journals OIL IDENTIFICATION ON SET OF PHYSICAL AND CHEMICAL INDICATORS OF QUALITY

2017 ◽  
Vol 19 (3) ◽  
pp. 128-133
Author(s):  
A.L. Lobachev ◽  
N.V. Fomina ◽  
I.V. Lobacheva ◽  
E.V. Revinskaya
Keyword(s):  
Chemical Indicators ◽  
Physical And Chemical ◽  
Simple Materials

Approaches to identification of materials, based on component-wise analysis that is applicable only to rather simple materials, when probably complete division and further identification of individual components of a mix are shined. The system of identification of oil on the basis of determination of set of physical and chemical indicators of quality of oil according to GOST 51851-2002 is offered.

A Study of X-Ray Fluorescence Method with Vacuum and Air-Path Spectrographs for the Determination of Film Thicknesses of II-VI Compounds

1967 ◽  
Vol 11 ◽  
pp. 191-203
Author(s):  
Frank L. Chan
Keyword(s):  
Energy Conversion ◽  
Vacuum Chamber ◽  
Fluorescence Method ◽  
Chemical Methods ◽  
X Ray ◽  
Aerospace Application ◽  
Physical And Chemical ◽  
Orange Color

AbstractFilms of II-VI compounds have been prepared by vacuum technique for the determination of their thicknesses. Some difficulties have been experienced in preparing good quality films- The positron of the substrate in the vacuum chamber, the rate of deposition, and the temperature of sublimation are some of the factors influencing the quality of these films. For instance, films of cadmium sulfide could be prepared in the usual yellow or orange color or in colors ranging from brown to black, depending on the conditions enumerated. For energy conversion, a film of proper thickness is one of the requirements for aerospace application. Among the various methods used for the determination of the thickness of these films, X-ray fluorescence can be performed rapidly and nondestructively. After determination of thickness by the X-ray fluorescence method, the samples can be used for other determinations and for energy conversion without their efficiency's having been affected. Other physical and chemical methods have been worked out. Comparison of these methods with the X-ray fluorescence method is made. Procedures and results are presented.

scholarly journals Analisis parameter fisika kimia air pada lokasi karamba jaring tancap di Danau Tondano Kabupaten Minahasa Provinsi Sulawesi Utara

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Abdul J. Sarif ◽  
Diane J. Kusen ◽  
Novie P.L. Pangemanan
Keyword(s):  
Water Quality ◽  
Quality Standard ◽  
Quality Parameters ◽  
Chemical Parameter ◽  
North Sulawesi ◽  
Net Cages ◽  
Physical And Chemical ◽  
Culture Site

This research was to determine the current condition of the water physical chemical quality parameters at culture areas in Lake Tondano. The study  conducted at Lake Tondano Minahasa Regency, North Sulawesi Province.  Determination of the water physical and chemical qualitis was carried through field observation and laboratorium analysis at the Industrial Research and Standardization in Manado. Measurement and retrieval of physical and chemical parameter of water quality was done at culture site with high density, medium and small especially at Eris Village, Leleko Village and Toulour Village. Water temperature was 26oC - 29oC, brightness of 1.34-2.8 cm, depth of 4.23-11.8 m, acidity of 6.7-7.8 mg/L, dissolved oxygen, 2.75–6.31 mg/L, nitrate 0.00-1.58 mg/L, nitrite 0.00–0.027 mg /L, ammonia 0.00–0.292 mg/L and phosphate 0.02–0.721 mg/L.  The results showed that water quality of Lake Tondano still match the quality standard of water quality for fish cultivation except ammonia.Keywords: water quality, net cages, Lake Tondano

scholarly journals Development of stability indicating method for quality assessment of African Albendazole tablets

2021 ◽  
Vol 319 ◽  
pp. 01084
Author(s):  
Amine Hssaine ◽  
Miloud El Karbane ◽  
Mohamed Azougagh ◽  
Imad Eddine Houti ◽  
Brahim Benaji
Keyword(s):  
Gradient Elution ◽  
The United States ◽  
Hplc Method ◽  
Stability Indicating ◽  
Stability Indicating Method ◽  
The Stability ◽  
Physical And Chemical ◽  
States Pharmacopeia

In order to assess the quality of Albendazole tablets (Alb) sampled in three countries from West Africa, several physical and chemical tests were performed on tablets at normal conditions. A simple and economic HPLC method has been developed, validated and used for the simultaneous determination of Albendazole (Alb) content, as well as its impurities and the uniformity of its content. The stability-indicating HPLC method was performed on a Symmetry C18-5µm 250 mm × 4.6 mm column with a gradient elution using a mobile phase composed of acetonitrile and sodium acetate buffer. The flow rate was set at 1 mL.min−1 and the eluent was monitored at 295nm. The method was validated for specificity, linearity, accuracy, precision, robustness and detection and quantification limits, in accordance with International Conference on Harmonisation Quality 2 (ICH Q2) guidelines. This method was performed on different Alb samples (originals and generics) products collected from Senegal, Niger and Mali. The obtained results showed that, the contents of the generic tablets from Niger and Mali comply with the United States Pharmacopeia (USP) monograph acceptance criteria. However, more than 20% of the generic tablets don’t meet the USP monograph impurity limits. In conclusion, the described analytical method is simple, sensitive and accurate. Thus, it could be useful for manufacturing and quality control assays.

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