droplet nuclei

Examples of droplet nuclei in the following topics:

• Portals of Exit

  • The lower the humidity, the quicker the mucus shell evaporates thus allowing the droplet nuclei to stay airborne and not drop to the ground.
  • The low indoor humidity levels in wintertime buildings ensure that higher levels of droplet nuclei will survive: droplet nuclei are so microscopic that they are able to stay airborne indefinitely on the air currents present within indoor spaces.
  • When an infected person coughs or sneezes, a percentage of their viruses will become droplet nuclei.
  • If these droplet nuclei gain access to the eyes, nose, or mouth of an uninfected person (known as a susceptible) – either directly, or indirectly by touching a contaminated surface – then the droplet nuclei may penetrate into the deep recesses of their lungs.
  • Viral diseases that are commonly spread by coughing or sneezing droplet nuclei include the common cold and influenza.

• Chain of Transmission

  • Transmission occurs when droplets containing microbes from the infected person are propelled a short distance through the air and deposited on the host's body; droplets are generated from the source person mainly by coughing, sneezing, and talking, and during the performance of certain procedures, such as bronchoscopy.
  • Dissemination can be either airborne droplet nuclei (small-particle residue {5 µm or smaller in size} of evaporated droplets containing microorganisms that remain suspended in the air for long periods of time) or dust particles containing the infectious agent.

• The Millikan Oil-Drop Experiment

  • In 1911, using charged droplets of oil, Robert Millikan was able to determine the charge of an electron.
  • Millikan designed his experiment to measure the force on oil droplets between two electrodes.
  • He used an atomizer to spray a mist of tiny oil droplets into a chamber, which included a hole.
  • Millikan then exposed the droplets to X-rays, which ionized molecules in the air and caused electrons to attach to the oil droplets, thus making them charged.
  • Although the charge of each droplet was unknown, Millikan adjusted the strength of the X-rays ionizing the air and measured many values of (q) from many different oil droplets.

• Millikan's Oil Drop Experiment

  • The oil drop experiment calculated the charge of an electron using charged oil droplets suspended in an electric field.
  • They suspended tiny charged droplets of oil between two metal electrodes by balancing downward gravitational force with upward drag and electric forces.
  • A fine mist of oil droplets was sprayed into a chamber above the plates.
  • Q is the charge of an electron, E is the electric field, m is mass of the droplet, and g is gravity.
  • The droplets enter the space between the plates and can be controlled by changing the voltage across the plates.

• Airborne Transmission of Disease

  • The pathogens are capable of traveling distances on air currents when they are present on either dust particles or small respiratory droplets.
  • The airborne transmission that occurs utilizes small particles or droplet nucleithat contains these infectious agents or pathogens.
  • These particles and droplets are capable of remaining suspended in air for extended periods of time.
  • The ability of these droplets to remain suspended for long periods of time result in the lack of face-to-face contact for infection.

• Nuclear Fusion

  • In nuclear fusion two or more atomic nuclei collide at very high speed and join, forming a new nucleus.
  • The sun is a main-sequence star and therefore generates its energy through nuclear fusion of hydrogen nuclei into helium.
  • It takes considerable energy to force nuclei to fuse, even nuclei of the lightest element, hydrogen.
  • This is because all nuclei have a positive charge due to their protons, and since like charges repel, nuclei strongly resist being put close together.
  • The fusion of lighter nuclei, which creates a heavier nucleus and often a free neutron or proton, generally releases more energy than it takes to force the nuclei together.

• Nuclear Fusion

  • Nuclear fusion is the process by which two or more atomic nuclei join together, or "fuse," to form a single heavier nucleus.
  • The nuclear force is stronger than the Coulomb force for atomic nuclei smaller than iron, so building up these nuclei from lighter nuclei by fusion releases the extra energy from the net attraction of these particles.
  • For larger nuclei, no energy is released, since the nuclear force is short-range and cannot continue to act across an even larger atomic nuclei.
  • Therefore, energy is no longer released when such nuclei are made by fusion; instead, energy is absorbed.
  • Therefore, the main technical difficulty for fusion is getting the nuclei close enough to fuse.

• Spin-Spin Splitting

  • This is usually observed if the spin-coupled nuclei have very different chemical shifts (i.e.
  • Nuclei having the same chemical shift (called isochronous) do not exhibit spin-splitting.
  • The splitting pattern of a given nucleus (or set of equivalent nuclei) can be predicted by the n+1 rule, where n is the number of neighboring spin-coupled nuclei with the same (or very similar) Js.
  • Spin 1/2 nuclei include 1H, 13C, 19F & 31P.
  • The spin-coupling interactions described above may occur between similar or dissimilar nuclei.

• Binding Energy and Nuclear Forces

  • Nuclear force is the force that is responsible for binding of protons and neutrons into atomic nuclei.
  • The nuclear force is the force between two or more component parts of an atomic nuclei.
  • Nuclear force is responsible for the binding of protons and neutrons into atomic nuclei.
  • Conversely, energy is released when a nucleus is created from free nucleons or other nuclei—known as the nuclear binding energy.
  • The binding energy of nuclei is always a positive number, since all nuclei require net energy to separate into individual protons and neutrons.

• Pons

  • The pons contains nuclei that relay signals from the forebrain to the cerebellum, along with nuclei that regulate sleep, respiration, swallowing, bladder control, hearing, equilibrium, taste, eye movement, facial expressions, facial sensation, and posture.
  • The alar plate produces sensory neuroblasts, which will give rise to the solitary nucleus and its special visceral afferent column, the cochlear and vestibular nuclei (which form the special somatic afferent fibers of the vestibulocochlear nerve), the spinal and principal trigeminal nerve nuclei (which form the general somatic afferent column of the trigeminal nerve), and the pontine nuclei, which is involved in motor activity.
  • Basal plate neuroblasts give rise to the abducent nucleus (forms the general somatic efferent fibers), the facial and motor trigeminal nuclei (form the special visceral efferent column), and the superior salivatory nucleus, which forms the general visceral efferent fibers of the facial nerve.
  • A number of cranial nerve nuclei are present in the pons: