Seasonal Changes in the Limnology of Some Meromictic Lakes in Southern British Columbia

1969 ◽  
Vol 26 (7) ◽  
pp. 1763-1787 ◽  
Author(s):  
T. G. Northcote ◽  
T. G. Halsey
Keyword(s):  
Seasonal Changes ◽  
Specific Conductivity ◽  
Solid Content ◽  
Lake Basin ◽  
Physical Chemical ◽  
Morphometric Features ◽  
Wide Range ◽  
Sulphur Bacteria ◽  
Total Dissolved Solid ◽  
Physical And Chemical

Seasonal changes in physical, chemical, and biological features are described in four small lakes which show different types and degrees of meromixis. There is a wide range in total dissolved solid content between lakes as well as within lakes (surface to near-bottom): Yellow, 282 (surface) to 337 (bottom); White, 6229–7918; Mahoney, 10,003–86,906; Lyons, 12,116–222,195 mg/liter, but no marked seasonal changes. In Yellow Lake meromixis is probably maintained by morphometric features of the lake basin rather than a strong chemocline; in the other lakes complete mixing is inhibited by chemical density gradients, those in Mahoney and Lyons being especially sharp.Summer, autumn, winter (under ice), and spring vertical profiles are presented for temperature, dissolved oxygen, pH, alkalinity, specific conductivity; differences within and between lakes are discussed. Other physical–chemical characteristics are given in less detail.Purple sulphur bacteria occur in three of the lakes (White, Mahoney, Lyons) and in the latter two form discrete "plates" detectable by high frequency echo sounding (confirmed by sampling). Seasonal changes in depth of the bacterial plates are considered in relation to some physical and chemical parameters. Phytoplankton, zooplankton, and benthos communities are discussed in relation to the degree of meromixis shown by the lakes.

scholarly journals The Effect of Coating as Antifungi of Harumanis Mango's Post Harvest Losses

2020 ◽  
Vol 1 (2) ◽  
pp. 7-16
Author(s):  
Winda Amilia ◽  
Andrew Setiawan Rusdianto ◽  
Arma Dwi Novemi
Keyword(s):  
Corn Starch ◽  
Chemical Properties ◽  
Inhibition Zone ◽  
Post Harvest ◽  
Physical Chemical ◽  
Chemical Content ◽  
Total Dissolved Solid ◽  
Tobacco Extract ◽  
Physical And Chemical

The amount of mango production in Indonesia is quite high, but the quality of postharvest mangoes is still quite low. The quality of the fruit will decline due to contamination; one of the contaminants is fungi. The way to reduce the damage of postharvest products is by coating applications. The purpose of this study was to study the physical, chemical and antifungal activities of harumanis mangoes’s quality which had been given coating during storage that could cause postharvest losses of harumanis mangoes. There are 3 treatments, each of them are respectively the provision of corn based coating  6% tobacco extract, 8% tobacco extract and 10% tobacco extract. The physical and chemical properties of the antifungal coating of tobacco extract made from corn coating for post-harvest damage on harumanis mangoes were obtained by weight loss, texture, colour, respiration rate, vitamin C and total dissolved solid. Preventing coating can prevent damage after harvest and protect the harumanis mango; therefore the quality of the mangoes can be maintained. The best results from the priority with the largest diameter inhibition zone were given corn starch 10% tobacco extract. Then the higher the concentration of extract used, the greater the diameter of the inhibition zone obtained. Based on all the tests performed (physical, chemical, and antifungal) the best treatment from the treatment was obtained that consisted of mangoes with antifungal layers of corn starch 10% tobacco extract. Because the P3 obtained the best results in maintaining physical, chemical content and fungi for 15 days.

scholarly journals Comparative Limnology of Lakes in the Southern Rocky Mountain Trench, British Columbia

1966 ◽  
Vol 23 (12) ◽  
pp. 1875-1895 ◽  
Author(s):  
R. A. H. Sparrow
Keyword(s):  
British Columbia ◽  
Geographical Area ◽  
Rocky Mountain ◽  
Detailed Examination ◽  
Bottom Fauna ◽  
Lake Basin ◽  
Wide Range ◽  
Total Dissolved Solid ◽  
Climatic Characteristics ◽  
Restricted Geographical Area

Within a restricted geographical area of British Columbia, detailed examination in 1960 and 1961 of nine lakes having similar morphometric and climatic characteristics but exhibiting a wide range in dissolved nutrients (50 to 1463 ppm) suggested that, standing crops of plankton were related to oxygen deficits and perimeter-to-area ratios of the lakes. Total dissolved solid contents of the lakes were not closely correlated to standing crops of plankton, bottom fauna, or fish. Ranking by selected physical or chemical indices of productivity failed to agree with ranking based on standing crops or various biological measurements of productivity. Water level fluctuation, perimeter-to-area ratios, lake basin shape, and the size and nature of the drainage area are discussed as some of the possible factors which interact to modify the expression of the primary factors in productivity.

Indices of Productivity in British Columbia Lakes

1956 ◽  
Vol 13 (4) ◽  
pp. 515-540 ◽  
Author(s):  
T. G. Northcote ◽  
P. A. Larkin
Keyword(s):  
British Columbia ◽  
Total Dissolved Solids ◽  
Solid Content ◽  
General Level ◽  
Bottom Fauna ◽  
Significant Relation ◽  
Dissolved Solids ◽  
Hyperbolic Curve ◽  
Total Dissolved Solid ◽  
Physical And Chemical

The relation between physical and chemical indices of production and standard crops of plankton, bottom fauna and fish was examined in 100 British Columbia lakes. A significant increase in plankton and fish quantities with increase in total dissolved solid content of lake waters was demonstrated and a similar relationship suggested for bottom fauna. Although the general form of the relationship between mean depth and plankton, and between bottom fauna and fish quantity, suggested a hyperbolic curve with larger quantities in lakes of low mean depth, the only generalization which seemed justified was that quantities of fauna from lakes of great mean depth were never as high as those found in some lakes of low mean depth. No significant relation was found between intensity and length of growing season and quantities of plankton, bottom fauna or fish, although a significant relationship was demonstrated between summer epilimnion temperature and plankton.In a multiple regression analysis using all lakes the predominance of total dissolved solids over mean depth in affecting summed indices of lake fauna was shown. However for lakes in the southern interior plateau, one of the 9 regions distinguished in British Columbia, no significant relation could be demonstrated between mean depth or total dissolved solids and summed indices of fauna or plankton alone. Thus total dissolved solid content of the water appeared to be the most important factor in determining the general level of productivity in lakes studied throughout the province, although within a region neither total dissolved solids nor mean depth could be used either singly or together to predict plankton, bottom fauna or fish quantities.

Oxide Film Formation on Metals and Alloys by Thermal, Electrochemical and Plasma Oxidation and Prediction of Resulting Structures

1999 ◽  
Vol 574 ◽  
Author(s):  
D. L. Cocke ◽  
S. Promreuk ◽  
R. Schennach ◽  
M. Y. Mollah ◽  
D. G. Naugle
Keyword(s):  
Electric Fields ◽  
Film Formation ◽  
Complex Oxide ◽  
Metals And Alloys ◽  
Plasma Oxidation ◽  
Chemical Mechanisms ◽  
Physical Chemical ◽  
Layer Structures ◽  
Wide Range ◽  
Physical And Chemical

AbstractMulticomponent oxide films are needed to meet the increasing demands of the electronics industry. Three main methods that involve oxidation of a metallic substrate are thermal, anodic and plasma oxidation. Today we do not have an adequate fundamental physical-chemical model of how multicomponent oxides evolve on alloys under these oxidizing conditions to design a wide range of materials for electronic devices. The three methods will be discussed in terms of physical/chemical parameters that influence the chemical nature and structure of the resulting oxides. By using surface studies of the oxidation behavior of numerous metals and alloys we have been able to delineate the factors which are most important to the oxide formation process and provide insight into the prediction of oxide layer structures. The electrochemical processes that occur during the materials reaction with a chosen environment will be used to discuss the physical and chemical mechanisms involved. Intrinsic and extrinsic electric fields will be shown to influence the chemical and structural nature of the resulting oxide structures. Examples will be presented from a number of metal and alloy systems that have been examined in our laboratory. These include Al, Ti, Zr, Nb, Mn, Cu and Ni and some of their selected alloys. The models that have developed from these studies are providing some predictive power in how the complex oxide overlayer will be chemically speciated and on its structure.

scholarly journals Palladium and Copper: Advantageous Nanocatalysts for Multi-Step Transformations

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1891
Author(s):  
Antonio Reina ◽  
Trung Dang-Bao ◽  
Itzel Guerrero-Ríos ◽  
Montserrat Gómez
Keyword(s):  
Chemical Properties ◽  
Added Value ◽  
Solid Supports ◽  
Nanosized Materials ◽  
Nano Structures ◽  
Liquid Phases ◽  
Wide Range ◽  
Synthetic Methodologies ◽  
Physical And Chemical ◽  
A Current

Metal nanoparticles have been deeply studied in the last few decades due to their attractive physical and chemical properties, finding a wide range of applications in several fields. Among them, well-defined nano-structures can combine the main advantages of heterogeneous and homogenous catalysts. Especially, catalyzed multi-step processes for the production of added-value chemicals represent straightforward synthetic methodologies, including tandem and sequential reactions that avoid the purification of intermediate compounds. In particular, palladium- and copper-based nanocatalysts are often applied, becoming a current strategy in the sustainable synthesis of fine chemicals. The rational tailoring of nanosized materials involving both those immobilized on solid supports and liquid phases and their applications in organic synthesis are herein reviewed.

Nanobiotechnology: Nature-inspired silver nanoparticles towards green synthesis

2021 ◽  
pp. 0958305X2198988
Author(s):  
Nur Syakirah Rabiha Rosman ◽  
Noor Aniza Harun ◽  
Izwandy Idris ◽  
Wan Iryani Wan Ismail
Keyword(s):  
Electrical Conductivity ◽  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Metal Nanoparticles ◽  
Current Trend ◽  
Biological Properties ◽  
Noble Metal Nanoparticles ◽  
Current Application ◽  
Physical Chemical ◽  
Physical And Chemical

The emergence of technology to produce nanoparticles (1 nm – 100 nm in size) has drawn significant researchers’ interests. Nanoparticles can boost the antimicrobial, catalytic, optical, and electrical conductivity properties, which cannot be achieved by their corresponding bulk. Among other noble metal nanoparticles, silver nanoparticles (AgNPs) have attained a special emphasis in the industry due to their superior physical, chemical, and biological properties, closely linked to their shapes, sizes, and morphologies. Proper knowledge of these NPs is essential to maximise the potential of biosynthesised AgNPs in various applications while mitigating risks to humans and the environment. This paper aims to critically review the global consumption of AgNPs and compare the AgNPs synthesis between conventional methods (physical and chemical) and current trend method (biological). Related work, advantages, and drawbacks are also highlighted. Pertinently, this review extensively discusses the current application of AgNPs in various fields. Lastly, the challenges and prospects of biosynthesised AgNPs, including application safety, oxidation, and stability, commercialisation, and sustainability of resources towards a green environment, were discussed.

scholarly journals Hybrid Acrylated Chitosan and Thiolated Pectin Cross-Linked Hydrogels with Tunable Properties

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 266
Author(s):  
Shaked Eliyahu ◽  
Alexandra Galitsky ◽  
Esther Ritov ◽  
Havazelet Bianco-Peled
Keyword(s):  
Electrostatic Interactions ◽  
Profile Analysis ◽  
Hybrid Hydrogel ◽  
Texture Profile ◽  
Ph Values ◽  
X Ray Scattering ◽  
Wide Range ◽  
Michael Type Addition ◽  
Physical And Chemical ◽  
Hydrogel System

We developed and characterized a new hydrogel system based on the physical and chemical interactions of pectin partially modified with thiol groups and chitosan modified with acrylate end groups. Gelation occurred at high pectin thiol ratios, indicating that a low acrylated chitosan concentration in the hydrogel had a profound effect on the cross-linking. Turbidity, Fourier transform infrared spectroscopy, and free thiol determination analyses were performed to determine the relationships of the different bonds inside the gel. At low pH values below the pKa of chitosan, more electrostatic interactions were formed between opposite charges, but at high pH values, the Michael-type addition reaction between acrylate and thiol took place, creating harder hydrogels. Swelling experiments and Young’s modulus measurements were performed to study the structure and properties of the resultant hydrogels. The nanostructure was examined using small-angle X-ray scattering. The texture profile analysis showed a unique property of hydrogel adhesiveness. By implementing changes in the preparation procedure, we controlled the hydrogel properties. This hybrid hydrogel system can be a good candidate for a wide range of biomedical applications, such as a mucosal biomimetic surface for mucoadhesive testing.

Study of the physical, chemical and rheological properties of oil mixtures transported through the Uzen - Atyrau - Samara pipeline

2021 ◽  
pp. 420-427
Author(s):  
Берик Картанбаевич Саяхов ◽  
Александр Геннадьевич Дидух ◽  
Гульнара Амангельдиевна Габсаттарова ◽  
Марат Давлетович Насибулин ◽  
Жасулан Канатович Наурузбеков
Keyword(s):  
Rheological Properties ◽  
Pour Point ◽  
Heating Temperature ◽  
High Viscosity ◽  
Rheological Parameters ◽  
Polarization Microscopy ◽  
Oil Pipeline ◽  
Physical Chemical ◽  
Wide Range ◽  
Oil Mixtures

На начальных участках магистрального нефтепровода Узень - Атырау - Самара формируются партии низкозастывающих бузачинских и высокозастывающих мангышлакских нефтей. По маршруту транспортировки осуществляются дополнительные подкачки нефтей с различными физико-химическими и реологическими характеристиками, что может оказывать существенное влияние на свойства перекачиваемых нефтесмесей. Цель настоящей работы - исследование физико-химических и реологических свойств бузачинской и мангышлакской нефтесмесей на маршруте поставки Узень - Атырау, а также диапазона и причин изменений характеристик бузачинской нефти (основной в компонентном составе нефтесмесей, перекачиваемых по нефтепроводу Узень - Атырау - Самара). По результатам исследований установлено, что свойства мангышлакской нефтесмеси изменяются в незначительных пределах. Для бузачинской нефтесмеси свойственна нестабильность реологических параметров, которые могут изменяться в широком диапазоне в результате путевой подкачки на различных участках нефтепровода. Колебания реологических параметров наиболее показательных проб партий бузачинской нефтесмеси рекомендуется учитывать для решения задач повышения текучести высоковязких нефтей и оптимизации технологических режимов работы трубопроводов, по которым осуществляется перекачка таких нефтей. Методами газохроматографического анализа молекулярно-массового распределения тугоплавких парафинов и поляризационной микроскопии определена температура нагрева бузачинской и мангышлакской нефтесмесей, оптимальная для ввода депрессорной присадки. At the initial sections of the Uzen - Atyrau - Samara main oil pipeline, batches of low pour point Buzachinsky and high pour point Mangyshlak oils are formed. Additional pumping of oils with different physical, chemical and rheological characteristics is carried out along the transportation route, which can have a significant effect on the properties of the pumped oil mixtures. The purpose of this study is to examine the physical, chemical and rheological properties of Buzachi and Mangyshlak oil mixtures on the Uzen - Atyrau supply route, as well as the range and causes of changes in the characteristics of Buzachinsky oil (the main oil mixture in the blend composition pumped through the Uzen - Atyrau - Samara pipeline). According to the research results, it was found that the properties of the Mangyshlak oil mixture vary within insignificant limits. The Buzachinsky oil mixture is characterized by instability of rheological parameters, which can vary in a wide range as a result of route pumping at different pipeline sections. Fluctuations of the rheological parameters of the most indicative samples of batches of the Buzachinsky oil mixture are recommended to be taken into account in order to increase the fluidity of high-viscosity oils and optimize the process modes of operation of pipelines through which such oils are pumped. Using the methods of gas chromatographic analysis of the molecular weight distribution of high-melting-point paraffins, as well as polarization microscopy, the optimal heating temperature for the introduction of a pour point depressant into the Buzachinsky and Mangyshlak oil mixtures has been determined.

Adsorption–Desorption Characteristics of ss-DNA on 2D TpTta-COF Studied by Fluorescently Labeled Oligonucleotides

NANO ◽  
2021 ◽  
pp. 2150050
Author(s):  
Zhaoyu Han ◽  
Sen Li ◽  
Shaoxian Yin ◽  
Zhi-Qin Wang ◽  
Yanfei Cai ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Kinetic Mechanism ◽  
Optical Biosensors ◽  
Desorption Kinetic ◽  
Wide Range ◽  
Potential Applications ◽  
Fluorescently Labeled Oligonucleotides ◽  
Adsorption Desorption ◽  
Physical And Chemical ◽  
And Chemical Properties

Being the newest member of the 2D materials family, 2D-nanosheet possesses many distinctive physical and chemical properties resulting in a wide range of potential applications. Recently, it was discovered that 2D COF can adsorb single-stranded DNA (ss-DNA) efficiently as well as usefully to quench fluorophores. These properties make it possible to prepare DNA-based optical biosensors using 2D COF. While practical analytical applications are being demonstrated, the fundamental understanding of binding between 2D COF and DNA in solution received relatively less attention. In this work, we carried out a systematic study to understand the adsorption and desorption kinetic, mechanism, and influencing factors of ss-DNA on the surface of 2D COF. We demonstrated that shorter DNAs are adsorbed more rapidly and bind more tightly to the surface of 2D COF. The adsorption is favored by a higher pH. The different buffer types also can affect the adsorption. In Tris-HCl solution, the adsorption reached highest efficiency. By adding the complementary DNA (cDNA), desorption of the absorbed DNA on 2D COF can be achieved. Further, desorption efficiency can also be exchanged by various surfactant in solution. These findings are important for further understanding of the interactions between DNA and COFs and for the optimization of DNA and COF-based devices and sensors.

Application of neural networks in membrane separation

2020 ◽  
Vol 36 (2) ◽  
pp. 265-310 ◽  
Author(s):  
Morteza Asghari ◽  
Amir Dashti ◽  
Mashallah Rezakazemi ◽  
Ebrahim Jokar ◽  
Hadi Halakoei
Keyword(s):  
Neural Networks ◽  
Chemical Engineering ◽  
Membrane Separation ◽  
Mechanistic Model ◽  
Computing Time ◽  
Permeate Flux ◽  
Practical Applications ◽  
Advantages And Disadvantages ◽  
Wide Range ◽  
Physical And Chemical

AbstractArtificial neural networks (ANNs) as a powerful technique for solving complicated problems in membrane separation processes have been employed in a wide range of chemical engineering applications. ANNs can be used in the modeling of different processes more easily than other modeling methods. Besides that, the computing time in the design of a membrane separation plant is shorter compared to many mass transfer models. The membrane separation field requires an alternative model that can work alone or in parallel with theoretical or numerical types, which can be quicker and, many a time, much more reliable. They are helpful in cases when scientists do not thoroughly know the physical and chemical rules that govern systems. In ANN modeling, there is no requirement for a deep knowledge of the processes and mathematical equations that govern them. Neural networks are commonly used for the estimation of membrane performance characteristics such as the permeate flux and rejection over the entire range of the process variables, such as pressure, solute concentration, temperature, superficial flow velocity, etc. This review investigates the important aspects of ANNs such as methods of development and training, and modeling strategies in correlation with different types of applications [microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), reverse osmosis (RO), electrodialysis (ED), etc.]. It also deals with particular types of ANNs that have been confirmed to be effective in practical applications and points out the advantages and disadvantages of using them. The combination of ANN with accurate model predictions and a mechanistic model with less accurate predictions that render physical and chemical laws can provide a thorough understanding of a process.

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