This document discusses boiling and condensation processes. It defines boiling as a liquid to vapor phase change and condensation as a vapor to liquid phase change. The document describes different types of boiling including nucleate, critical heat flux, transition, and film boiling. It also discusses pool boiling and flow boiling. For condensation, it covers film condensation and dropwise condensation. The key applications of boiling and condensation are in heat exchangers and refrigeration systems.
Shell and Tube Heat Exchanger in heat TransferUsman Shah
This slide will explain you the chemical engineering terms .Al about the basics of this slide are explain in it. The basics of fluid mechanics, heat transfer, chemical engineering thermodynamics, fluid motions, newtonian fluids, are explain in this process.
Shell and Tube Heat Exchanger in heat TransferUsman Shah
This slide will explain you the chemical engineering terms .Al about the basics of this slide are explain in it. The basics of fluid mechanics, heat transfer, chemical engineering thermodynamics, fluid motions, newtonian fluids, are explain in this process.
Understand the physical mechanism of convection and its classification.
Visualize the development of velocity and thermal boundary layers during flow over surfaces.
Gain a working knowledge of the dimensionless Reynolds, Prandtl, and Nusselt numbers.
Distinguish between laminar and turbulent flows, and gain an understanding of the mechanisms of momentum and heat transfer in turbulent flow.
Derive the differential equations that govern convection on the basis of mass, momentum, and energy balances, and solve these equations for some simple cases such as laminar flow over a flat plate.
Non dimensionalize the convection equations and obtain the functional forms of friction and heat transfer coefficients.
Use analogies between momentum and heat transfer, and determine heat transfer coefficient from knowledge of friction coefficient.
HEAT EXCHANGERS. Heat exchangers are devices that facilitate the exchange of heat between two fluids that are at different temperature while keeping them from mixing with each other.
2. Double Pipe Heat Exchangers
3. A typical double pipe heat exchanger basically consists of a tube or pipe fixed concentrically inside a larger pipe or tube They are used when flow rates of the fluids and the heat duty are small (less than 5 kW) These are simple to construct, but may require a lot of physical space to achieve the desired heat transfer area.
4. Double-pipe exchangers is the generic term covering a range of jacketed 'U' tube exchangers normally operating in countercurrent flow of two types which is true double pipes and multitubular hairpins. One fluid flows through the smaller pipe while the other fluid flows through the annular space between the two pipes. Two types of flow arrangement: Parallel flow Counter flow
5. • The fluids may be separated by a plane wall but more commonly by a concentric tube (double pipe) arrangement shown in fig. If both the fluids move in the same direction, the arrangement is called a parallel flow type. In the counter flow arrangement the fluids move in parallel but opposite directions. In a double pipe heat exchanger, either the hot or cold fluid occupies the annular space and the other fluid moves through the inner pipe. The method of solving the problem using logarithmic mean temperature difference is typical and more iteration must be done. So it takes more time for the problem to solve. Therefore another method is practiced for solving this type of problems. This method is known as Effectiveness and Number of Transfer Units or simply ε-NTU method.“Effectiveness of heat exchangers is defined as actual heat transfer rate by maximum possible heat transfer rate”.The LMTD method may be applied to design problems for which the fluid flow rates and inlet temperatures, as well as a desired outlet temperature, are prescribed.
6. Application of Double Pipe Heat Exchanger Pasteurization or sterilization of food and bioproducts Condensers and evaporators of air conditioners Radiators for internal combustion engines Charge air coolers and intercoolers for cooling supercharged engine intake air of diesel engines.
GATE Mechanical Engineering notes on Heat Transfer. Use these notes as a preparation for GATE Mechanical Engineering and other engineering competitive exams. For full course visit https://mindvis.in/courses/gate-2018-mechanical-engineering-online-course or call 9779434433.
introduction of condensation, what is it types etc. horizontal condenser, vertical condenser, process aplications, all examples related to the process,
Understand the physical mechanism of convection and its classification.
Visualize the development of velocity and thermal boundary layers during flow over surfaces.
Gain a working knowledge of the dimensionless Reynolds, Prandtl, and Nusselt numbers.
Distinguish between laminar and turbulent flows, and gain an understanding of the mechanisms of momentum and heat transfer in turbulent flow.
Derive the differential equations that govern convection on the basis of mass, momentum, and energy balances, and solve these equations for some simple cases such as laminar flow over a flat plate.
Non dimensionalize the convection equations and obtain the functional forms of friction and heat transfer coefficients.
Use analogies between momentum and heat transfer, and determine heat transfer coefficient from knowledge of friction coefficient.
HEAT EXCHANGERS. Heat exchangers are devices that facilitate the exchange of heat between two fluids that are at different temperature while keeping them from mixing with each other.
2. Double Pipe Heat Exchangers
3. A typical double pipe heat exchanger basically consists of a tube or pipe fixed concentrically inside a larger pipe or tube They are used when flow rates of the fluids and the heat duty are small (less than 5 kW) These are simple to construct, but may require a lot of physical space to achieve the desired heat transfer area.
4. Double-pipe exchangers is the generic term covering a range of jacketed 'U' tube exchangers normally operating in countercurrent flow of two types which is true double pipes and multitubular hairpins. One fluid flows through the smaller pipe while the other fluid flows through the annular space between the two pipes. Two types of flow arrangement: Parallel flow Counter flow
5. • The fluids may be separated by a plane wall but more commonly by a concentric tube (double pipe) arrangement shown in fig. If both the fluids move in the same direction, the arrangement is called a parallel flow type. In the counter flow arrangement the fluids move in parallel but opposite directions. In a double pipe heat exchanger, either the hot or cold fluid occupies the annular space and the other fluid moves through the inner pipe. The method of solving the problem using logarithmic mean temperature difference is typical and more iteration must be done. So it takes more time for the problem to solve. Therefore another method is practiced for solving this type of problems. This method is known as Effectiveness and Number of Transfer Units or simply ε-NTU method.“Effectiveness of heat exchangers is defined as actual heat transfer rate by maximum possible heat transfer rate”.The LMTD method may be applied to design problems for which the fluid flow rates and inlet temperatures, as well as a desired outlet temperature, are prescribed.
6. Application of Double Pipe Heat Exchanger Pasteurization or sterilization of food and bioproducts Condensers and evaporators of air conditioners Radiators for internal combustion engines Charge air coolers and intercoolers for cooling supercharged engine intake air of diesel engines.
GATE Mechanical Engineering notes on Heat Transfer. Use these notes as a preparation for GATE Mechanical Engineering and other engineering competitive exams. For full course visit https://mindvis.in/courses/gate-2018-mechanical-engineering-online-course or call 9779434433.
introduction of condensation, what is it types etc. horizontal condenser, vertical condenser, process aplications, all examples related to the process,
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
(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.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
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 .
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
5. BOILING
The Temprature at which the vapor pressure of the liquid is equal to the
pressure exerted on the liquid by the surrounding atmosphere.
The boiling point of water is 100 °C or 212 °F, but is lower with the decreased
atmospheric pressure found at higher altitudes.
Types:-
Nucleate
Critical heat flux
Transition
film
5
9. CRITICAL HEAT FLUX
Heated above a critical temperature, a film of vapor forms on the
surface.
Since this vapor film is much less capable of carrying heat away from
the surface, the temperature rises very rapidly.
9
10. TRANSITION BOILING
Unstable boiling,the heater surface is covered by a vapor film, which
acts as an insulation.
The formation of bubbles in a heated liquid is a complex physical
process which often involves cavitation.
10
11. FILM BOILING
Heater surface is completely covered by a continuous stable vapor
film, where the heat flux reaches a minimum is called the
“Leidenfrost point”.
11
12. 12
Subcooled Boiling
When the temperature of the
main body of the liquid is
below the saturation
temperature.
Saturated Boiling
When the temperature of the
liquid is equal to the
saturation temperature.
13. POOL BOILING
Boiling takes different forms, depending on the,
DTexcess = Ts Tsat
13
In pool boiling, the fluid is not forced to flow by a mover such as a
pump.
Any motion of the fluid is due to natural convection currents and the
motion of the bubbles under the influence of buoyancy.
Boiling Regimes and the Boiling Curve
14. FLOW BOILING
In flow boiling, the fluid is forced to move
by an external source such as a pump as it
undergoes a phase-change process.
External flow boiling over a plate or
cylinder is similar to pool boiling, but the added
motion increases both the nucleate boiling heat flux
and the maximum heat flux considerably.
Internal flow boiling, commonly
referred to as two-phase flow, is much more
complicated in nature because there is no free
surface for the vapor to escape, and thus both the
liquid and the vapor are forced to flow together.
14
15. 15
The two-phase flow in a
tube exhibits different flow boiling
regimes, depending on the relative
amounts of the liquid and the vapor
phases.
Note that the tube contains a liquid
before the bubbly flow regime and a
vapor after the mist-flow regime.
16. Slug flow
• Bubbles coalesce into slugs of vapor.
• Moderate mass qualities
Annular flow
• Core of the flow consists of vapor only, and liquid
adjacent to the walls.
• Very high heat transfer coefficients
Mist flow
• A sharp decrease in the heat transfer coefficient
Vapor single-phase flow
• The liquid phase is completely evaporated and vapor is
superheated.
16
Liquid single-phase flow
• In the inlet region the liquid is subcooled and heat transfer to the liquid is by forced convection
(assuming no subcooled boiling).
Bubbly flow
• Individual bubbles
• Low mass qualities
18. 18
Film condensation
The condensate wets the surface and forms a liquid
film.
The surface is blanketed by a liquid film which serves
as a resistance to heat transfer.
Drop wise condensation
The condensed vapor forms droplets on the surface.
The droplets slide down when they reach a certain size.
No liquid film to resist heat transfer.
As a result, heat transfer rates that are more than 10
times larger than with film condensation can be
achieved.
CONDENSATION HEAT
TRANSFER
19. Liquid film starts forming at the top of the plate
and flows downward under the influence of
gravity.
Heat in the amount hfg is released during
condensation and is transferred through the
film to the plate surface.
Ts must be below the saturation temperature for
condensation.
The temperature of the condensate is Tsat at the
interface and decreases gradually to Ts at the
wall.
19
FILM CONDENSATION
20. FLOW REGIMES
The dimensionless parameter controlling the
transition between regimes is the Reynolds
number defined as:
Three prime flow regimes:
Re < 30 ─ Laminar (wave-free)
30 < Re < 1800 ─ Laminar (wavy)
Re > 1800 ─ Turbulent
The Reynolds number increases in the flow
direction.
20
21. 21
Heat transfer in condensation depends on whether the condensate
flow is laminar or turbulent. The criterion for the flow regime is
provided by the Reynolds number.
22. HEAT TRANSFER CORRELATIONS
FOR FILM CONDENSATION
Assumptions:
Both the plate and the vapor are maintained at
constant temperatures of Ts and Tsat, respectively,
and the temperature across the liquid film varies
linearly.
Heat transfer is pure conduction.
The velocity of the vapor is low (or zero) so that it
exerts no drag on the condensate (no viscous shear
on the liquid–vapor interface).
The flow of the condensate is laminar (Re<30) and
the properties of the liquid are constant.
22
VERTICAL PLATES
23. 23
INCLINED PLATES
it can also be used for laminar film condensation on the
upper surfaces of plates that are inclined by an angle from
the vertical, by replacing g in that equation by g cos.
VERTICAL TUBES
the average heat transfer coefficient for laminar film
condensation on the outer surfaces of vertical tubes
provided that the tube diameter is large relative to the
thickness of the liquid film.
24. 24
Horizontal Tubes and Spheres
The average heat transfer coefficient for film condensation
on the outer surfaces of a horizontal tube is
For a sphere, replace the constant 0.729 by 0.815.
A comparison of the heat transfer coefficient relations for a vertical tube of height L
and a horizontal tube of diameter D yields
25. 25
HORIZONTAL TUBE BANKS
The average thickness of the liquid film at the lower tubes is much larger as a
result of condensate falling on top of them from the tubes directly above.
Therefore, the average heat transfer coefficient at the lower tubes in such
arrangements is smaller.
26. 26
EFFECT OF VAPOR VELOCITY
In the analysis above we assumed the vapor velocity to be small and thus the vapor
drag exerted on the liquid film to be negligible, which is usually the case.
If the vapor flows downward,this additional force will increase the average velocity
of the liquid, decrease the film thickness.
decrease the thermal resistance of the liquid film and thus increase heat transfer.
Upward vapor flow has the opposite effects: the vapor exerts a force on the liquid in
the opposite direction to flow, thickens the liquid film, and thus decreases heat
transfer.
27. 27
THE PRESENCE OF NONCONDENSABLE
GASES IN CONDENSERS
Even small amounts of a noncondensable gas in the
vapor cause significant drops in heat transfer coefficient
during condensation.
It is common practice to periodically vent out the
noncondensable gases that accumulate in the condensers
to ensure proper operation.
A high flow velocity is more likely to remove the
stagnant noncondensable gas from the vicinity of the
surface, and thus improve heat transfer.
28. 28
FILM CONDENSATION INSIDE
HORIZONTAL TUBES
refrigeration and air-conditioning applications involve
condensation on the inner surfaces of horizontal or vertical tubes.
Heat transfer analysis of condensation inside tubes is complicated
by the fact that it is strongly influenced by the vapor velocity and the
rate of liquid accumulation on the walls of the tubes.
For low vapor velocities:
The Reynolds number of the vapor is to be evaluated at the tube inlet
conditions using the internal tube diameter as the characteristic length.
29. 29
DROPWISE CONDENSATION
Dropwise condensation, characterized by countless droplets
of varying diameters on the condensing surface instead of a
continuous liquid film.
The small droplets that form at the nucleation sites on the
surface grow as a result of continued condensation, coalesce
into large droplets, and slide down when they reach a certain
size, clearing the surface and exposing it to vapor. There is no
liquid film in this case to resist heat transfer.
heat transfer coefficients can be achieved that are more
than 10 times larger than film condensation.
Dropwise condensation of
steam on copper surfaces:
30. Boiling heat transfer
Pool boiling
Boiling regimes and the boiling curve
Flow boiling
Condensation heat transfer
Film condensation
Film condensation inside horizontal tubes
Drop wise condensation
30
SUMMARY