PM

PayMaster. Who pays the piper calls the tune.

PM

Performance Monitoring.

PM

Permanent Magnet. A ferromagnetic material with an alignment of domains that produces a net magnetization.

PM

Phase Modulation.

PM

Physical Medium.

PM

Plasma Membrane[s].

PM

Popular Mechanics. On the cover, underneath the title, the words

Written so you can understand it.

PM

Post Meridiem (after noon).

PM

PostMaster.

PM

PostMortem.

PM

Presentation Manager.

PM

Preventive Maintainance. The least sexy activity.

PM

Prime Minister. Catch up on who is the latest Japanese PM here. Read quickly, the page has a timed fuse.

Say you're standing on a street corner of Main Street, U.S.A., and a fellow from the ``CBC'' comes up and says he wants to ask you a few questions. He comes up with a real obscure one like ``who's the prime minister of Canada?'' You haven't had the time lately to bone up on your international trivia, and you didn't even realize that Canada had a national church. No problem! Just answer ``Rick Mercer'' and smile.

PM

Project Manager.

.pm

(Domain code for) St. Pierre and Miquelon.

Pm

Promethium. Atomic number 61. Named after the titan who gave fire to man and was punished by having birds pick at his immortal innards. Eventually he cooperated (became an informer, ratted) with the olympian authorities to get off that rock. Learn more, but only about this rare earth (RE) element and not Greek mythology, at its entry in WebElements and its entry at Chemicool.

It's hard to fight the feeling that it ought to be PromethEum.

PMA

Pennsylvania Manufacturers' Association.

PMA

Precision Metalforming Association.

PMA

Produce Marketing Association.

PMA

Property Management Assocation. For example, here's a link to the PMA of Western Michigan, an NAA affiliate.

PMA

Publishers Marketing Association. ``The largest non-profit trade association representing independent publishers of books, audio, video and CDs.''

Hey, we're all trying to move product -- apples, books, whatever.

PMAA

Petroleum Marketers Association of America. But see also CSP.

PMAEF

Precision Metalforming Association (PMA) Educational Foundation.

PMAN

Polymethactylonitrile (polymer).

PMB

Pietermaritzburg. A symbol or initialism used in South Africa.

PMBR

Preliminary Multistate Bar Review.

PMBZ

Prosopographie de mittelbyzantinischen Zeit. A five-volume encyclopedia, copyright 2001. They're thick volumes, but not that thick: PMBZ is the form of the title that appears on the spine. Even on the cover, mittelbyzantinischen is hyphenated.

PMC

Postmodern Culture. ``An electronic journal of interdisciplinary criticism, published by North Carolina State University, Oxford University Press, and the University of Virginia's Institute for Advanced Technology in the Humanities.''

PMCCN

(International Conference on the) Performance and Management of Complex Communication Networks.

PMD

Physical-Medium-Dependent (sub-layer; layer in the sense of OSI model).

PMD

Pre-Metal Dielectric.

PMDC

Permanent Magnet Direct Current (DC) (motor). The permanent magnet(s) provide the fixed (external) field surrounding the rotor. They replace the ``stator'' field windings in a shunt motor.

PMEL

Pacific Marine Environmental Laboratory. A facility of the US NOAA, it ``carries out interdisciplinary scientific investigations in oceanography and atmospheric science.''

PMETs

Professionals, Managers, Executives, and TechnicianS. The acronym is common in Singapore, and apparently nowhere else, as of February 2009.

ME (Pi Mu Epsilon)

National Mathematics Honor Society.

PMFJI

Pardon Me For Jumping In. Email abbreviation. PMJI is also used.

PM-FTIR

polarization modulation Fourier Transform InfraRed (FTIR) (spectroscopy).

PMG

PostMaster General.

PMHEMT

PseudoMorphic High Electron Mobility Transistor (HEMT).

PMI

Private Mortgage Insurance.

PM&I

Program Management and Integration.

PMI

Project Management Institute. Tests and certifies project management professionals (PMP's).

PMI

Purchasing Managers' Index.

PMIPK

Poly Methyl IsoPropenyl Ketone.

PMJI

Pardon My Jumping In. Email abbreviation. PMFJI is also used.

PML

Perfect Matched Layer (numerical boundary conditions). Scheme for constructing Absorbing Boundary Conditions (ABC's).

PML

Progressive Multifocal Leukoencephalopathy. A neuropsychiatric disease caused by JC-viral infection. Devastating. Occurs in a few percent (estimates around 5%) of AIDS patients. Symptoms hard to distinguish from AIDS dementia (q.v.), but progress (not my choice of word) is more rapid.

PMMA

Poly(methyl methacrylate). Common resist for electron-beam- and ion-beam-lithography, and for light-beam photography in energies from UV to X-rays. Basically, it's a positive resist: the pattern of exposed polymer is damaged and dissolves more easily in developer solution.

Okay now, we're going to step through the simple organic chemistry of this plastic in the order dictated by the derivation of its name. This is going to be so simple, even I could understand it. [In fact, I might as well warn you, if you know anything about organic chemistry this will just about make you retch, but it's still better than if it made you a wretch.] First off, ``acrylic acid'' is just a confusing name for propenoic acid. Now propane is a three-carbon alkane (a flammable gas at room temp.); it has only one form: CH₃CH₂CH₃. This is also written H₃CCH₂CH₃ and just plain C₃H₈. It doesn't matter, there's only one stable compound with this formula.

          H    H    H
          |    |    |
     H -- C -- C -- C -- H
          |    |    |
          H    H    H

Representing carbons by kinks in, or ends of, a chain of C-C bonds, omitting to indicate H's, this becomes:

              /
             /
        ____/

(In this mode of displaying organic compounds, the precise compound can be reconstructed by satisfying the valency of all carbons by adding as many hydrogens as necessary. This is a very efficient scheme for representing organic compounds, since carbon chains and lots of boring hydrogen predominate.)

Propene is an alkene, an alkane with a double bond. Since the two C-C bonds of propane are equivalent, there is no need to indicate which bond is doubled. The formula is CH₂:CHCH₃, which we can represent

        H      H    H
         \     |    |
          C == C -- C -- H
         /     |    |
        H      H    H

or

              /
             /
        ____/
        ¯¯¯¯

Organic acids are formed by replacing methyl (-CH₃) with carboxyl (-COOH) groups, so propenoic acid can only be CH₂:CHCOOH ...

        H           O--H
         \          |
          C == C -- C == O
         /     |
        H      H

or (in a representation that more closely approximates the physical conformation)

              H--O
                  \
          H        C == O
           \      /
            C == C
           /      \
          H        H

or (most schematically)

           HO
             \
              \== O
              /
             /
        ____/
        ¯¯¯¯

Methacrylic acid is 2-methyl propenoic acid: a methyl (CH₃) group has been substituted for the hydrogen on carbon number 2 (the middle carbon) of the backbone to yield CH₂:C(CH₃)COOH. (Really, there's no need to specify 2-methyl, since putting the methyl group on the only other available carbon would mean that the molecule should have been designated butenoic acid. Oh, well, what do I know about IUPAC nomenclature?)

           H
          /
         /
        O
         \
          \
H          C == O
 \        /
  \      /
   C == C     H
  /      \   /
 /        \ /
H          C
          / \
         /   \
        H     H
or

           HO
             \
              \== O
              /
             /
        ____/
        ¯¯¯¯\
             \
              \

Up to this point, I reemphasize, the construction has followed the nomenclature and not the synthesis. Methyl methacrylate is an ester: methanol has been reacted with methacrylic acid in what resembles an acid-base reaction.

Methanol was previously known as methyl alcohol; an even older name is wood alcohol. It is present in minute quantities, and occasionally not-so-minute quantities, in the cheap stuff winos drink. As is well known, enough (and not that much) methanol will blind or kill you. In Simon and Garfunkel's song ``Blessed'' (from the Sounds of Silence album) winos are called ``meth drinkers.'' There were roadblocks and a scandal a couple of decades ago when cheap table wine imported from Italy to France was found to be contaminated with methanol, but you'll have to track that old news down yourself. The SBF offers recipes for a couple of recent-traditional Soviet poisons (Tears of a Komsomol Girl and Spirit of Geneva).

In esterification, which is a standard synthesis, the OH groups from the acid and alcohol combine to release one water molecule and leave a single bond through oxygen. In the present example: CH₂:C(CH₃)COOCH₃ ...

                      H     H
                       \   /
                        \ /
        H           O -- C -- H
         \          |
          C == C -- C == O
         /     |
        H      C -- H
              / \
             /   \
            H     H

or

       ---- O
             \
              \== O
              /
             /
        ____/
        ¯¯¯¯\
             \
              \

Because this molecule has a carbon-carbon double bond, there is a natural mechanism for its polymerization. Energy supplied by a photon of UV light is sufficient to break the double bond and initiate polymerization. This process tends to continue because the process of bonding to a neighbor breaks the neighbor's double bond and makes a new carbon reactive. The resulting chain has the following monomer unit:

       	       H 
               |
               |
	  H -- C -- H
	      /
	     /
	    O
             \
              \
       H       C == O
        \      |
         \     |
· · ----- C -- C ----- · ·
         /     |
        /      |
       H       C -- H
              / \
             /   \
            H     H

San Diego Plastics, Inc. serves a short page of application-oriented information on PMMA plastic. There's an informative PMMA entry in the Macrogalleria.

PMMA was first discovered in the 1870's, but was first commercialized by Rohm and Haas in 1935 as Plexiglas. DuPont brought out PMMA as Lucite in 1937.

PMMA/MAA

A copolymer of methyl methacrylate (vide PMMA supra) and methacrylic acid. A beam resist.

PMMU

Paged Memory Management Unit.

PMMW

Passive MilliMeter Wave (imaging).

PMN

PolyMorphoNuclear leucocyte.

PMN

PreManufacture Notice. Required by the TSCA, as noted at the CHEMEST entry.

PMO

Prime Minister's Office.

pMOS, PMOS

P-channel MOSFET, which in digital logic occurs primarily in conjunction with nMOS in CMOS circuits.

There's not much utility for pMOS alone, since everything you can do with pMOS alone you can do with nMOS alone, but the higher mobility of electrons than holes in commercial (and indeed most simple) semiconductor materials gives nMOS a higher gain factor.

PMP

PolyMethylPentene (plastic). (Mitsui Petrochemical Industries, Ltd.: TPX ®.)

PMP

Post-Metal Programming. National Semiconductor (tm) term for the strategy of using nearly-finished, tested nMOS NOR ROM to speed the hardware development process. Generally speaking, nMOS technology is the cheapest basis for ROM that can be programmed before leaving the fab. The two main types of nMOS ROM are NOR and NAND. From the standpoint of PMP, the crucial difference is that the bit pattern of NOR core can be written at a late stage of fabrication, while the bit pattern for NAND core must be written at an early stage. In detail:

nMOS NAND ROM, zeros and ones are typically implemented by a diffusion or implantation mask that shifts a transistor threshhold voltage (so the transistor is always on). Thus, bit pattern storage must be done relatively early in fabrication, before metal or polysilicon row lines are deposited (the row line functions as a gate where it crosses over a bit line -- bit lines are diffused or implanted). In contrast, nMOS NOR ROM's are encoded at a late stage of fabrication (the bit pattern is stored by contacting or not contacting transistor drains to bit lines). (It can also be performed at a very late stage of fabrication by means of a high-energy implantation.) Thus, NMOS NOR ROM chips can be pretested and stored, and large numbers of chips can be available almost immediately after the ROM program is written.

PMP

Project Management Professional.

PMPA

Precision Machined Products Association.

pMPN

Pre-Markan Passion Narrative. A document that is either no longer extant or never existed.

PMQ

Prime Minister Question time. An entertainment sponsored by the British House of Commons. In terms of posturing and bogus news generation, roughly, comparable to presidential press conferences in the US. Apart from some linguistic conventions (e.g., the PM answers for ``the government'' -- the parliamentary party in power), the main difference in the presumed adversarial position of the questioners: In a US presidential press conference, the press is nominally neutral, and poses questions crafted to put the president in the uncomfortable position of having to make an embarrassing admission or be seen to avoid answering directly. In stark contrast, in PMQ the questioners are opposition MP's who pose questions crafted to put the president in the uncomfortable position of having to make an embarrassing admission or be seen to avoid answering directly.

PMR

Partido de la Revolución Mexicana. `Party of the Mexican Revolution.' The revolution was not televised, but a good time was had by all. Okay, not true. More factish statements at the PRI entry.

PMR

Private Mobile Radio.

PMRA

Pest Management Regulatory Agency of Health Canada.

PMRF

Pacific Missile Range Facility.

PMS

Particle Measuring Systems. (Company name.)

PMS

Performance Management System. [Standard avionics.]

PMS

PreMenstrual Syndrome. The non-crime that dares you to speak its name. Also ``Putting up with Men's S...'' and ``Postal Management Syndrome.''

PMS

Post-Modern Slut.

PM scholarship

Papa-Mama SCHOLARSHIP. A euphemism for no scholarship in the ordinary sense at all. Like a marital fellowship, it's not an arrangement with a very official status.

PMSW

Polymer MicroStructure Waveguide.

PMT

Phiroz Mehta Trust. Phiroz Mehta (1902-1994) seems to have been a syncretistic guru. I feel transcendent already.

PMT

PhotoMultiplier Tube. A sensitive photon detector. An evacuated tube with a number of electrodes of increasing positive voltage onbliquely facing each other (geometries vary). Any single particle impinging on a low-voltage anode produces a cascade of increasingly amplified current, as each stage emits more electrons than it receives (multiplies). It's a photo multiplier tube because the initial electrode receives a photon and emits one or more electrons (photoelectric effect).

Here's some instructional material from Virginia Tech.

PMTCT

Prevention of Mother-To-Child Transmission of (a disease or disease-causing agent). The term is not used to refer to amniocentesis to detect bad genes. In fact, the term mostly seems to refer to preventing a human fetus from being infected with AIDS.

pmu

Physical Mass Unit. The atomic mass unit, according to the definition favored by physicists, back when chemists and physicists used different definitions. Read the details at this amu entry.

PMVE

Perfluoro(Methyl Vinyl Ether).

PMW

Palestinian Media Watch.

PMYMHMMFSWGAD

Pardon Me, You Must Have Mistaken Me For Someone Who Gives A Damn.

A common expression, and an abbreviation that occurs frequently in newsgroup acronym lists, but never in actual postings. Cf. tanstaafl.

PM-10, PM₁₀

Particulate Matter of diameter less than 10 micrometers.

pn

p-type semiconductor, then n-type semiconductor, together. A bipolar junction. A homojunction, but not just any homojunction (it could be n-n⁺ or n-n^-, or something similar with p).

PN

Passion Narrative. Described in Christian gospels. One of the many questions that occur in HJ studies is whether Mark (see Mk 14-16) invented the PN out of whole cloth, or whether there was a pre-existing tradition for it (set aside what actually happened and who might have known).

Disagreements between the Matthean and Lucan PN's (and BN's and resurrection stories), coexisting with a large number of agreements between the two (sometimes together against Mark), are the principal motivation for positing a distinct Q document.

PN

Petri Net.

.pn

(Domain code for) Pitcairn.

PN

Pottery Neolithic. Later part of the Neolithic period, when clay pottery was made. Cf. PPN

PN

Practical Nurse.

PN

Professional Network. The British electrical engineering organization (IEE) uses this abbreviation productively, approximately as the ACM uses SIG (Special Interest Group) and the IEEE uses ``[technical] society'' and ``council.''

PN

PseudoNoise. Pseudorandom Number sequence. Designates a spreading signal used in SS.

PNAC

Project for a New American Century. What -- did we use up the previous American century already? Aren't these things supposed to last, like, at least 90 years?

PNAC is a Washington, DC, think tank consisting of three thinkers plus, I think, some support personnel. It plays a major role in the current (2005) demonology of the US left. In the Boy Scouts, I learned that three of anything (fires in a line, for example) can be used as a symbol of danger. Maybe that played a role in the design of the tail-lights on the original Chevy Caprice/Impala series (two-light Bel Air excluded) and the Ford Mustang. Detroit must have forgotten, but they're not selling many cars now, are they? For some stupid remarks on the trilateral commission, another three-headed monster of legend, see our old conspiracy entry.

PNB

Pageant News Bureau. Beauty pageant news. Reading this, you get the idea that there would be enough titles to go around if only they didn't give anyone more than one or two titles.

PNBA

Poly (n-Butyl Acrylic).

PNBH

Petri-Net-Based Hypertext.

PNC

People, Networks & Communication © (Conference). Sponsored by ICICX.

PNCFL

Pacific Northwest Council for Languages. ``[T]he oldest regional organization [i.e., ACTFL regional affiliate] of world-language teachers in the [US].''

PNET

Peaceful Nuclear Explosion Treaty.

When India entered the nuclear club, back in the seventies, they did not detonate any bomb. Noooo! Indira tested a peaceful nuclear device. Big difference.

PNF

Proprioceptive Neuromuscular Facilitation.

PNG

Pack 'N' Go. The name of various programs, tools, and options, and associated data formats (this PNG is not one of them), that are supposed to simplify data transfer.

PNG

Papua New Guinea.

PNG

Pawnee National Grassland. In northern Colorado.

PNG

Persona Non Grata. Hey, you gotta go along to get along.

PNG, .png

Portable Network Graphics. A graphics format. According to this authoritative page, this PNG is not related to the others listed around this entry. (English avoids these homograph confusions by the method of randomized vowel insertion. The disambiguation symbols can be distinguished from ordinary vowels by the fact that they have nothing necessarily to do with the pronunciation, just like the consonants. As you know, English uses a logographic script as Chinese does, but the logographs are constructed from a finite ``alphabet'' of strokes called letters. The logograph ``radicals'' of English are borrowed from Swahili and other languages.)

PNG

Professional Numismatists Guild.

pnicogen, pnictogen

An element in the nitrogen group. (group VA American, VB European, 15 IUPAC). From the Greek pnígein, `to choke.' You would choke in an all-nitrogen atmosphere, I guess, but you would also choke in an all-argon atmosphere. It only happens that air is about 78% nitrogen and only about 1% argon.

PNL

Batelle (Memorial Institute-operated) Pacific Northwest Laboratories of the Department of Energy, in Richland, WA.

PNLF

Planetary-Nebula Luminosity Function. Used to determine distances of galaxies as far as 100 Mpc away.

PNM, .pnm

Portable aNyMap. An image format: MIME-type image/x-portable-anymap.

Any idea what that means?

PNMR

Proton Nuclear Magnetic Resonance (NMR). The other popular one is based on the C¹² nucleus.

PNNI, P-NNI

Private Network-to-Network Interface.

PNP, PnP

Plug'N'Play. Substantially facilitated by object-oriented coding.

This is different from `pay to play.' In `pay to play,' a citizen (C) makes a contribution to a political candidate (P), and later the public official (P) spends public moneys ($) or writes legislation (pork) in a way that benefits the citizen (C). The ``citizen'' may be a citizen, a corporation, or a foreign government. In the last case, pay-to-play may be illegal.

pnp

A BJT with net n-doped base and p-doped collector and emitter. Traditionally, IC manufacture used n-doped substrates (taking advantage of factor-of-three higher mobility of electrons over holes in silicon), and was dominated by npn transistors.

PNR

Partido Nacional Revolucionario. `National Revolutionary Party' of Mexico. Original name of the PRI, q.v.

PNS

The Pakistan News Service. Distributed on the bitnet lists PAKISTAN@ASUACAD and PAKISTAN@PSUVM, with a bidirectional gateway (at American University) to a moderated (by the PNS editors) usenet newsgroup <bit.listserv.pakistan>. A little bit more at .pk entry.

PNS

The Philosophy News Service. Came into being in June 2004. Of course, if it came into being, then it is one of those entities that is ever in the process of becoming, and therefore is not. That's not news, that's Plato. Too bad, it might have useful humor content, if it existed. There's a mailing list, too.

PNS

Peripheral Nervous System.

PNS Syndrome

PIN-Number Syndrome. The term PNS Syndrome is an instance of an AAP pleonasm, as is the term AAP pleonasm (an acronym-assisted AAP pleonasm, in fact). The unconscious use of an AAP pleonasm, or the conscious use with reckless disregard, is an instance of PNS Syndrome. This sentence and the last might be examples of PNS Syndrome. This sentence is not.

Early in the 21st century, The New Scientist magazine has been doing a number of columns on the phenomenon, which it calls ``RAS Syndrome.''

PNTR

Permanent Normal Trading Relations.

PNUD

Programa de las Naciones Unidas para el Desarrollo. Spanish, `United Nations Development Program' (UNDP).

PNUE

Programme des Nations Unies pour l'environnement. French for UNEP.

Next section: PO (top) to PPVT (bottom)

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