The document discusses corrosion monitoring and prevention methods. It describes several techniques used to monitor corrosion rates, including the use of corrosion coupons, electrical resistance monitoring, linear polarization resistance monitoring, and galvanic monitoring. It also outlines various corrosion prevention methods such as proper material selection and design, use of corrosion resistant alloys, protective coatings like metallic coatings and inorganic coatings, cathodic protection, and eliminating corrosive agents from the environment.
This topic includes various aspects regarding Corrosion prevention. It includes material of construction, how environment changes and its effect on corrosion, how can we properly design our equipment to avoid from corrosion. It also includes Cathodic protection and Anodic protection.
This topic includes various aspects regarding Corrosion prevention. It includes material of construction, how environment changes and its effect on corrosion, how can we properly design our equipment to avoid from corrosion. It also includes Cathodic protection and Anodic protection.
A presentation covering the various methods of prevention of corrosion. Material selection, design of structures, alteration of materials, alteration of environment, cathodic & anodic protection, and coatings are the different methods used. These are briefly described.
When you design your product, you put a lot of money, energy and consideration into achieving the best possible function, good appearance and high reliability. Corrosion, wear and fatigue resistance may not be the first factors you consider.
However, material selection is crucial to obtain a long service life and to avoid damage such as operation failure – for instance due to inadequate mechanical strength - or unacceptable appearance due to corrosion products.
If you choose the correct materials for your product from the beginning, you can prevent damage deriving from corrosion, wear and mechanical impact. In many cases, you may completely avoid corrosion by choosing a resistant material for its actual application environment.
EIS is a powerful method of analyzing the complex electrical resistance of a system ( is sensitive
to surface phenomena and changes of bulk properties) It can be used to determine semi-quantitative parameters of electrochemical processes occurring
at electrode surfaces
Phosphine as ligand by Dr Geeta TewariGeeta Tewari
This presentation describes about the nature of phosphine ligands, bonding and reactions of metal phosphine containing complexes. Also explains the similarity and differences of phosphine ligand with NH3 and CO ligands.
A presentation covering the various methods of prevention of corrosion. Material selection, design of structures, alteration of materials, alteration of environment, cathodic & anodic protection, and coatings are the different methods used. These are briefly described.
When you design your product, you put a lot of money, energy and consideration into achieving the best possible function, good appearance and high reliability. Corrosion, wear and fatigue resistance may not be the first factors you consider.
However, material selection is crucial to obtain a long service life and to avoid damage such as operation failure – for instance due to inadequate mechanical strength - or unacceptable appearance due to corrosion products.
If you choose the correct materials for your product from the beginning, you can prevent damage deriving from corrosion, wear and mechanical impact. In many cases, you may completely avoid corrosion by choosing a resistant material for its actual application environment.
EIS is a powerful method of analyzing the complex electrical resistance of a system ( is sensitive
to surface phenomena and changes of bulk properties) It can be used to determine semi-quantitative parameters of electrochemical processes occurring
at electrode surfaces
Phosphine as ligand by Dr Geeta TewariGeeta Tewari
This presentation describes about the nature of phosphine ligands, bonding and reactions of metal phosphine containing complexes. Also explains the similarity and differences of phosphine ligand with NH3 and CO ligands.
Performance Characteristics of various Corrugated Roofing Sheets in Nigeriaijceronline
This Paper is based on an experiment carried out on different roofing sheets namely aluminum, galvanized steel, plastic and asbestos of various grades. The aluminum samples were obtained from two different companies in Nigeria namely First Aluminum and Tower Aluminum; the Asbestos was obtained from Emenite while the Steel and Plastic samples were bought from the market. The samples were cut into a particular size (8cm by 5cm) and immersed in various media namely acidic (H2SO4), alkaline (NaOH), Sea water and Rain water in 2litres plastic beakers. The Rain water was used as the control medium for the experiment. The experiment was carried out for 70days and each grade was cut into 14 pieces of the same dimension. The samples were washed, weighed and tagged before immersion in the media. Each sample was removed every 5 days, washed thoroughly, dried and re-weighed. Some of the samples corroded while some resisted corrosion. The differences in the weights of the samples, and hence their respective rates of corrosion were obtained depending on the reacting media. The values that were obtained, the weight loss and weight gain were used to determine the corrosion rates per unit area per unit time. Graphs of specific weight loss/gain against time were plotted for each medium and each sample. Based on our graphs and observations, we can say that the coated samples are more resistant to corrosion, and therefore more durable.
The presentation covers various aspects of coating and deposition process in detail. The topics that are mainly covered in this PPT are
1) Type of Coating
2) Advantages and limitation for various coating process
3) Figures of various coating process
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
Comparative structure of adrenal gland in vertebrates
Corrosion Monitoring and Prevention methods
1. 1
CORROSION MONITORING AND
PREVENTION METHODS
INTRODUCTION
Corrosion monitoring and prevention methods involve the use of
techniques which measure corrosivity of assets in a particular
environment, so that the harm which could occur to the
machinery/plant could be prevented or delayed.
CORROSION MONITORING METHODS
Corrosion Monitoring is the regular measurement of corrosivity
or rate of corrosion. It helps to diagnose a particular corrosion
problem and provide information related to maintenance
required by plant/system.
The various methods include:
1. Corrosion Coupons (Weight Loss)
It involves exposing of specimen alloy (the coupon) to a
process environment for a given duration (usually 90 days)
and then analysing the weight loss which is indicative of the
rate of corrosion.
2. Electrical Resistance (ER) Monitoring
ER technique measures the change in Ohmic resistance of
the corroding metal element using ER probes, in the
corroding environment. Due to the action of corrosion, the
resistance of metal increases (because surface area
2. 2
decreases) as a function of time, giving the rate of
corrosion.
3. Linear Polarisation Resistance (LPR) Monitoring
This technique is based on electrochemical theory. Here a
small voltage (polarisation potential) is applied to an
electrode in a clean aqueous electrolytic environment. The
measurement of current (the current needed to maintain a
specific voltage change) gives instantaneous rate of
corrosion.
4. Galvanic Monitoring
In this method, two electrodes of dissimilar metals are
exposed to the process fluid. The current generated due to
the potential difference relates to the rate of corrosion.
5. Specialised Monitoring
Examples are:
a) Biological Monitoring: By identifying the presence of
Sulphate Reducing Bacteria (SRBs).
b) Hydrogen Penetration Monitoring: H2 is produced as
a by-product during corrosion reaction which is
absorbed by steel. This can be analysed and used as an
indicator of corrosion rate.
3. 3
CORROSION PREVENTION METHODS
The main objective of corrosion prevention measures is to
control the process to acceptable limits. The common methods
employed are:
1. Proper Material Selection, Design and Construction
The surface of metal or alloy used for construction
should be smooth and homogenous.
If two metals are to be in contact, they should be so
selected that their oxidation potentials are very near.
If contact of dissimilar metals with larger difference in
oxidation potential is unavoidable, then they should be
insulated.
Shapes like sharp corners which favour the formation
of stagnant areas and accumulation of solids should be
avoided.
2. Use of Corrosion Resistant Alloys
Alloys like stainless steel, monel metal, duriron should be
used instead of pure metals.
3. Use of Protective Coatings
The type of protective coating depends on the corrosivity of
atmosphere, nature of structure (thickness), its life
expectancy and utility.
The various types of protective coatings are:
a) Metallic Coatings: Such coatings are usually applied
on iron and steel. The metals like Zn, Sn, Ni, Cu, Cr, Al
4. 4
and Pb are used to form coating by methods such as
electroplating, hot dipping, vapourising, etc.
b) Inorganic Non-Metallic Coatings: These are of
following types-
i. Chemical Dip Coating or Surface Conversion:
The metal is immersed in a solution of suitable
chemical which reacts with the surface to produce
adherent coating. Examples are chromate,
phosphate or oxide coatings on surface of metal or
alloy.
ii. Anodized Oxide Coating: Protective oxide films
are produced on Aluminium by making Aluminium
as anode in electrolytic bath containing oxidizing
agents. This is then immersed in boiling water to
decrease porosity and increase resistance to
corrosion.
iii. Vitreous Enamel Coating: These are usually
applied to cleaned steel and cast iron equipment in
the form of a powder mix or frit, which is later
fused onto the metal surface by heating.
c) Organic Chemical Coatings: These include paints,
varnishes, enamels, etc which are effective inert
barriers.
4. Cathodic or Sacrificial Anodic Protection
The metal to be protected is made cathode and another more
corrodible metal is made the anode which is replaced again
and again to protect the metal.
5. 5
Example: Use of an alloy of Zn and Mg as a sacrificial
anode for the protection of ship hulls.
5. Elimination of Corrosive Agents from Environment
This can be done in the following ways:
a) Deaeration: Removal of oxygen from aqueous
environment or deactivation by adding chemical which
combine with oxygen like sodium sulphite.
b) Dehumification: Reducing the amount of moisture in
the immediate environment using alumina or silica gel.
c) Alkaline Neutralisation: Neutralising the acidic
character of corrosive environment using alkaline
neutralizers like NH3, NaOH, lime, etc.
References:-
1. Advanced Physical Chemistry; Gurtu, J.N. and Gurtu, A.
2. Applied Chemistry for Home Science and Allied Sciences;
Jacob, Thankamma.
THANK YOU