1,831 research outputs found
Ab initio oscillator strengths for transitions between J=1 odd and J=1,2 even excited states of Ne I
Ab initio theory is developed for radiative transitions between excited
states of neon. Calculations of energies for even excited states J=1, J=2
supplement our previous calculations for J=1 odd excited states. Line strengths
for transitions between J=1 odd and J=1,2 even states of Ne I are evaluated. A
comparison with experiments and semiempirical calculations is given.Comment: 5 page
Virtual Pitch and Pitch Shifts in Church Bells
It is well established that musical sounds comprising multiple partials with frequencies approximately in the ratio of small integers give rise to a strong sensation of pitch even if the lowest or fundamental partial is missing—the so-called virtual pitch effect. Experiments on thirty test subjects demonstrate that this virtual pitch is shifted significantly by changes in the spacing of the constituent partials. The experiments measured pitch by comparison of sounds of similar timbre and were automated so that they could be performed remotely across the Internet. Analysis of the test sounds used shows that the pitch shifts are not predicted by Terhardt’s classic model of virtual pitch. The test sounds used were modelled on the sounds of church bells, but a further experiment on seventeen test subjects showed that changes in partial amplitude only had a minor effect on the pitch shifts observed, and that a pitch shift was still observed when two of the lowest frequency partials were removed, so that the effects reported are of general interest
Some problems concerning the provision of urban open space
There is conflict in the provision of open spaces in cities. On the one hand there is a need for ground for uses such as roads and sports grounds, and on the other hand the desire to provide housing to the largest number of people. The fixed allocation of space, based on the population figures, may not meet the requirements of the residents. The use of dynamic system simulation and behavioral norms can help to identify the right amount of space. The allocation of open space in the Republic has been done in a fairly unscientific way, and in order to base standards on the current state of affairs, the existing dissatisfaction can continue
Photoionization of Co and electron-impact excitation of Co using the Dirac R-matrix method
Modelling of massive stars and supernovae (SNe) plays a crucial role in
understanding galaxies. From this modelling we can derive fundamental
constraints on stellar evolution, mass-loss processes, mixing, and the products
of nucleosynthesis. Proper account must be taken of all important processes
that populate and depopulate the levels (collisional excitation, de-excitation,
ionization, recombination, photoionization, bound-bound processes). For the
analysis of Type Ia SNe and core collapse SNe (Types Ib, Ic and II) Fe group
elements are particularly important. Unfortunately little data is currently
available and most noticeably absent are the photoionization cross-sections for
the Fe-peaks which have high abundances in SNe. Important interactions for both
photoionization and electron-impact excitation are calculated using the
relativistic Dirac Atomic -matrix Codes (DARC) for low ionization stages of
cobalt. All results are calculated up to photon energies of 45 eV and electron
energies up to 20 eV. The wavefunction representation of Co III has been
generated using GRASP0 by including the dominant 3d, 3d[4s, 4p],
3p3d and 3p3d configurations, resulting in 292 fine structure
levels. Electron-impact collision strengths and Maxwellian averaged effective
collision strengths across a wide range of astrophysically relevant
temperatures are computed for Co III. In addition, statistically weighted
level-resolved ground and metastable photoionization cross-sections are
presented for Co II and compared directly with existing work.Comment: 11 pages, 8 figures and 4 table
Partial frequencies and Chladni’s law in church bells
The rim partials of a church bell (those with an antinode at the soundbow) generate the strike pitch or perceived note of the bell. The spacing in frequency of the higher rim partials has an important effect on the tonal quality of the bell. Investigations into the partial frequencies of 2752 bells, both bronze and steel, of a wide variety of dates, founders and sizes, show a simple and unexpected relationship between the frequencies of the rim partials. This relationship explains why attempts to tune the higher rim partials independently have failed. A modified version of Chladni’s law provides insight into the musical relationship of the partials, and predicts the partials of individual bells well, but fails to give a simple model of the spacing between the partials seen in bells with different profiles
Mood and motivation in shopping behaviour
This thesis is concerned with the motivation of shopping behaviour. The main aim of the research is to examine internal factors that influence a person's motivation, with specific focus on how consumers' shopping goals and mood states prior to a retail
encounter affect their in-store behaviour and the outcomes of the activity in terms of
goal attainment and evaluations of the retail outlet. The conceptual basis for the
research is provided by theories of goal-directed behaviour, which assume that people
are purposive in their behaviour and that there is a synergistic relationship between
cognition and motivation (Ratneshwar, 1995; Pervin, 1989). Two complementary
perspectives on the motivational role of mood are linked into this conceptualisation:
one that emphasises the role of associative cognitive networks and proposes that mood serves to regulate goal-directed behaviour by altering goal-relevant thought and perception (Gardner, 1985; Isen, 1984); the other that postulates that mood is a
biopsychological phenomenon that registers the availability of personal resources given near-term demands and alters goal-relevant thought, perception, and motivation in accordance with this (Morris, forthcoming; Batson et al., 1992; Thayer, 1989). In order to examine the motivation of shopping behaviour, an investigation was carried out amongst visitors to craft fairs in Scotland. The research adopted a quantitative approach. The data collection was driven by five main research hypotheses and involved asking consumers to complete two parts of a questionnaire: the first part was filled in upon their arrival at the craft fair and the second part was completed just before their departure. In this way, data on the progression of goal-directed behaviour over the course of a shopping episode was captured. The main findings of the research were that:
a) individuals' mood states prior to the retail encounter influenced consumers' levels
of commitment to shopping goals, although the importance of mood state varied
depending on the type of shopping goal in question;
b) types of behaviour exhibited in the course of shopping were influenced by the
types of goals that consumers identified to be important to them upon arriving at the craft fair and there was some evidence that individuals' mood states moderated the effects of their goals on their in-store behaviour;
c) attainment of shopping goals was dependent on whether the relevant goals were
specified as important prior to the retail encounter and in-store behaviour. Mixed
evidence was obtained on the role of mood as a factor that moderates the effects of commitment to goals on attainment of goals.
d) attainment of shopping goals was partly responsible for the change in a person's
mood state between entering and leaving the craft fair;
e) retail outcomes in terms of consumers' enjoyment of the retail encounter, their
preference for and intentions to patronise the retail outlet in the future were
influenced by consumers' evaluations of the extent to which they had attained their
shopping goals and their mood state following the shopping episode.
One of the main implications of the research is that a view of consumers as purposive
in their shopping activities makes a useful contribution to the understanding of shopping behaviour and how repeat patronage can be encouraged. As far as retailers
are concerned, there is a need to understand what goals consumers have in mind when they visit a store and how to facilitate behaviour directed towards the attainment of
those goals in order that consumers evaluate the shopping activity as successful and
leave with favourable impressions of the store. In addition, attempts to locate in an
environment that helps to boost the resources that contribute to mood, rather than draining them, and to smooth the way for goal-directed shopping activities may also increase repeat patronage and ultimately customer loyalty to retailers
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The Quantification of Strike Pitch and Pitch Shifts in Church Bells
The primary objective of the work reported in this thesis was to quantify how the pitch or strike note of a bell is determined by the frequencies of its partials. Pitches of bells are generally virtual pitch or missing fundamental effects, generated in the ear rather than present as a frequency in the radiated sound. The exact pitch is shifted from that expected for the missing fundamental by changes in the frequency of various partials. This can cause bells whose partials are in theory tuned precisely, to sound out of tune by considerable fractions of a semitone.
The pitch shifts were quantified at frequencies across the audible spectrum by a set of experiments carried out on 30 subjects. Subsidiary experiments established which partials create a bell’s pitch or pitches at different frequencies, and showed that partial amplitude does not significantly affect bell pitch. A simple model of pitch shift was devised from the test results which gave good agreement with the stretch tuning in a number of peals of bells. Stretch tuning has not previously been satisfactorily explained. The pitch shifts were also compared against Terhardt’s algorithm for virtual pitch, which did not predict the shifts seen in practice.
To prepare for these experiments, a comprehensive investigation was done of the partial frequencies of over 2,000 bells with a wide range of dates, weights and founders. An unexpected and straightforward relationship was found between the frequencies of the upper partials which generate virtual pitches, which seems to apply to all bronze and steel bells of Western shape. The relative frequencies of these partials are in turn determined by the thickness of the bell’s wall near the rim. This relationship between the partials has not been previously reported, and explains previous failed attempts by bellfounders to tune these partials independently. The modified version of Chladni’s law proposed by Perrin and Rossing for these partial frequencies was found not to give as good a fit to their frequencies as the relationship discovered in this research.
The work presented in this thesis is important for at least two reasons:
• It provides new practical guidance for the design and tuning of bells
• The shifts in virtual pitches observed as a result of upper partial changes support current research into pitch generation mechanisms in the human ear
Is There Enhanced Depletion of Gas-Phase Nitrogen in Moderately Reddened Lines of Sight?
We report on the abundance of interstellar neutral nitrogen (NI) for 30
sightlines, using data from the Far Ultraviolet Spectroscopic Explorer (FUSE)
and the Hubble Space Telescope (HST). NI column densities are derived by
measuring the equivalent widths of several ultraviolet absorption lines and
subsequently fitting those to a curve of growth. We find a mean interstellar
N/H of 51+/-4 ppm. This is below the mean found by Meyer et al. of 62(+4,-3)
ppm (adjusted for a difference in f-values). Our mean N/H is similar, however,
to the (f-value adjusted) mean of 51+/-3 ppm found by Knauth et al. for a
larger sample of sightlines with larger hydrogen column densities comparable to
those in this study. We discuss the question of whether or not nitrogen shows
increased gas-phase depletion in lines of sight with column densities
log(H_tot) >~ 21, as claimed by Knauth et al. The nitrogen abundance in the
line of sight toward HD 152236 is particularly interesting. We derive very
small N/H and N/O ratios for this line of sight that may support a previous
suggestion that members of the Sco OB1 association formed from an N-deficient
region.Comment: Accepted in The Astrophysical Journal, 9/2006 (expected pub. date:
1/2007) 38 pages, 5 figures (4 color
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