Propagation of gaseous detonation waves in a spatially inhomogeneous reactive medium

Detonation propagation in a compressible medium wherein the energy release has been made spatially inhomogeneous is examined via numerical simulation. The inhomogeneity is introduced via step functions in the reaction progress variable, with the local value of energy release correspondingly increased so as to maintain the same average energy density in the medium, and thus a constant Chapman Jouguet (CJ) detonation velocity. A one-step Arrhenius rate governs the rate of energy release in the reactive zones. The resulting dynamics of a detonation propagating in such systems with one-dimensional layers and two-dimensional squares are simulated using a Godunov-type finite-volume scheme. The resulting wave dynamics are analyzed by computing the average wave velocity and one-dimensional averaged wave structure. In the case of sufficiently inhomogeneous media wherein the spacing between reactive zones is greater than the inherent reaction zone length, average wave speeds significantly greater than the corresponding CJ speed of the homogenized medium are obtained. If the shock transit time between reactive zones is less than the reaction time scale, then the classical CJ detonation velocity is recovered. The spatio-temporal averaged structure of the waves in these systems is analyzed via a Favre averaging technique, with terms associated with the thermal and mechanical fluctuations being explicitly computed. The analysis of the averaged wave structure identifies the super-CJ detonations as weak detonations owing to the existence of mechanical non-equilibrium at the effective sonic point embedded within the wave structure. The correspondence of the super-CJ behavior identified in this study with real detonation phenomena that may be observed in experiments is discussed

The Ursinus Weekly, May 11, 1953

Ed Abramson elected prexy by thespians • Spirit Committee to hold election • Ursinus debaters triumph over LaSalle team, on FEPC • J. Alfred Kaye to speak at commencement, June 1 • Clubs elect 1953-54 heads • Cast receives high praise for Two blind mice production • New Y cabinet installed Sunday; Dance planned • Day Study elections decide new officers • Ruth Reed is May queen; Crowned under sunny sky • Seniors win study awards • Quartets present program, Tuesday • MSGA elections to be held Tuesday • Career offer for grads • Freshmen women elect soph rulers; Nesta Lewis to head committee • Editorials: But who shall decide? • Letters to the editor • Time machine • Mr. all-college visits U.C. and finds a way of life • To all happy drivers: We struggle for survival • Rittenhouse places in intercollegiates • Taylor hurls one-hitter; Belles defeat Beaver, 3-2 • PMC tops tracksters; Bears win 880, discus • Tennis team wins; Tops Albright, 5-4 • Baseball team wins, 5-4; Burger, Anderson star • Swarthmore wins meet 76-50; Swett, Eshbach win again • Sororities close year with dinner dances, shore tripshttps://digitalcommons.ursinus.edu/weekly/1520/thumbnail.jp

The Ursinus Weekly, April 20, 1953

Wilcox, Hirst, Rice speak on prof\u27s panel • Fotine to play Friday night • Miller shows pictures, speaks to IRC group • Laughton to read at Norristown, Sat. • Ursinus to be host to first Future Teacher\u27s convention • Informal initiations held • Student elections tomorrow, April 21; Petitioning begins for class officers • High class stuff acclaimed success • Ursinus Women\u27s Club entertains senior women • Meistersingers present Music for you, Thursday • Morrell, Frey, Hering, Field Ursinus bridge champions • Library gets map • Band will elect officers tomorrow • Editorials: Now is the time • Henrie, Long, Kutzer, Pollock elected to Chi Alpha offices • Letters to the editor • For smokers only • Swett wins in weights as track team loses • Ursinus, Neborak topple E\u27town • Harris stars as Bears, Carter rout Delaware • Girls beat Penn in tennis openerhttps://digitalcommons.ursinus.edu/weekly/1517/thumbnail.jp

The Ursinus Weekly, February 23, 1953

Summer school subjects to be selected now • 6th foreign policy institute to be Friday • Women elect Ruth Reed as May queen; Janie Hopple as manager for May Day • Y rep attends Bible study conf. • Dr. Harmin to be speaker at FTA Tuesday night at 7 • Jones to show slides • Detweiler to speak on religion in life day, February 25 • Rev. Flynn to speak tonight • Dr. Yost reads short stories at second English lit reading • Debaters defeat Princeton • Play tryouts to be this week; Group two to give plays • $52.92 collected for flood relief • French Club to give play at Penn, Thurs. • Quartet to sing • Dr. Bartholomew discusses rural church with Chi Alpha • Editorials: Enthusiasm needed; What happened? • Engagements • Letters to the editor • Fraternities sign 54 men • Science majors offered atomic energy posts • Margie changes from practice teaching to teaching position • Students examine Kimberton farms teaching methods • Ursinus men on the rocks as sirens comb their locks • Drexel rallies in last period to triumph 62-52 • Belles topple Garnet 42-24 • Grapplers edged out by Fords in last bout, 18-15 • Dawkins wins but Bears drop 21-5 match to Bucks • Mermaids dunk Drexel; Lose to powerful Garnet • Blood disease sidelines Swett • Haverford edges Bears 81-77 despite late surge • Belles rally to beat I.C. 42-38https://digitalcommons.ursinus.edu/weekly/1513/thumbnail.jp

The Ursinus Weekly, May 4, 1953

MSGA discusses plagiarism case; Decision rejected • Primary Wed. for M.S.G.A. class officers • Y presidents name cabinet • Sororities elect officers for coming year, 1953-54 • Nominees announced for Curtain Club elections, May 6 • Chem society plans banquet; Officers to be announced • New head waiters chosen • Ursinus-Albright exchange program hears students • Armstrong, Walker are chosen Ruby editors • Pageant, play highlight May Day weekend plans • New MSGA members to be installed, Monday • Retreat combines fun and worship • Doctors speak to pre-meders • Alumni address economics, political science classes • Editorials: Art at last! • Has book-burning begun? • Medical schools report on grads • An open letter praises life in a co-ed college • Belles defeat Rosemont, 4-1 • Experience aids Jayvee tennis • Jayvee court team wins, 4-1 • Trackmen drop trio meet; Lehigh routs Bears, 91-34 • Moravian tops tennis team • Softball team wins over Albright, 35-6 • Ball team wins, 18-4, 4-3; Loses 2-1 to Moravian • Women\u27s Club to sponsor tour of historic county homes • Meistersingers close seasonhttps://digitalcommons.ursinus.edu/weekly/1519/thumbnail.jp

Two-photon spectroscopy of the biphenyl chromophore. The electronic excited states of biphenyl and fluorene below 50000 cm-1

The two-photon excitation spectra of biphenyl and fluorene in dil. soln. were measured up to 50,000 cm-1. Both spectra exhibit a medium intense band system in the range 32,000-42,000 cm-1, and a strong band above 45,000 cm-1. The lowest frequency feature is assigned to a B3 symmetry transition in biphenyl and the corresponding B2 transition in fluorene. The polarization of the higher bands leads to the assignment of 2 A states at 38,000 and 47,000 cm-1. The origin of the electronically excited states of the biphenyl chromophore is discussed by simple composite mol. considerations as well as CNDO CI calcns. The latter give a semiquant. picture of transition energies and transition probabilities for 1- and 2-photon allowed excitations. A compilation of 1-photon spectra and calcns. from the literature is included in the anal. to provide a consistent picture of the electronically excited states of the biphenyl chromophore up to 50,000 cm-1

The Ursinus Weekly, March 15, 1954

John Canady addresses art seminar group • Ursinus to participate in cultural olympics at U. of P. • Cheating case reviewed by MSGA on Tuesday • Teacher problems outlined for FTA by Mrs. Swavely • Griffin, Mathewson star in group play • Lit readings postponed • Civil liberties today is discussed by Backrack • Women\u27s Club to fete senior girls at coffee • University of Pennsylvania Band to give concert, Thursday • Editorials: Goodbye, my fancy • Exhibit in Library • Broadway tunes highlight WAA musical production • Dave Seay, Marshall Nixon tell of service hitches • Reporter clipped by barber of Brodbeck • Doctor tells symptoms of dread Spring fever disease • Gene Harris, Carl Smith new cage co-captains • Mermaids lose to Swarthmore • Basketball season ends; Shoes leads statistics • Undefeated Belles top E. Stroudsburg • Intramural night occurs tomorrow • Badminton team downs Rosemont • Curtis I tops Curtis II for intramural honors • Ralph Schumacher named to first all MAC team • Bowman, Cross to inherit Weekly sports editing • God of creation viewed at vespers program, Sundayhttps://digitalcommons.ursinus.edu/weekly/1492/thumbnail.jp