2,011 research outputs found
A pilot demonstration project of technology application from the aerospace industry to city management (four cities program)
The Four Cities Program has completed the first year of the planned two-year program. At the beginning of the first year, a variety of program initiation activities were accomplished. Contracts were negotiated; science and technology advisors were interviewed, selected and assigned; general indoctrination and integration of the advisors into city affairs occurred; technical needs were identified and related projects pursued; pilot projects for the second year were identified; inter-city coordination on technical problems began to emerge; and the general soundness of the four cities program seems to have been established. Above all, the inter-personal relationships between the advisors and their interfaces in city government appear to be functioning smoothly. The establishment of such mutual respect, trusts, and confidences are believed essential to the success of the program
Montana\u27s Timber Harvest and Timber-Using Industry: A Study of Relationships
Paper published as Bulletin 41 in the UM Bulletin Forestry Series.https://scholarworks.umt.edu/umforestrybulletin/1025/thumbnail.jp
Research Note, January 1980
This is issue 13: Economic-Base Multipliers and the Wildland-Based Economy of Montanahttps://scholarworks.umt.edu/montana_forestry_notes/1012/thumbnail.jp
An Analysis of Cynicism Within Law Enforcement
An investigation and analysis of the concept of cynicism as part of a social process involving other sociological variables within two law enforcement agencies was undertaken. The major theoretical contention of this study was that within the law enforcement setting one consequence of employing certain organizational control mechanisms has been an accompanying generation of social strain relative to such control mechanisms. The Niederhoffer scale was employed as an objective measure of cynicism. Extended interviews were conducted with those who scored high on the cynicism scale. Two major sources of social strain were indicated by the interview responses: (a) the area of promotion and the related power struggles; (b) the area of judicial processes and recent court decisions
A Quarter Century of Geology at the Gulf Coast Research Laboratory (1948-1973)
Overview of the history of geology courses and research at the Gulf Coast Research Laboratory in Ocean Springs, Mississippi
A Quarter Century of Geology at the Gulf Coast Research Laboratory (1948-1973)
Overview of the history of geology courses and research at the Gulf Coast Research Laboratory in Ocean Springs, Mississippi
Distance to the scaling law: a useful approach for unveiling relationships between crime and urban metrics
We report on a quantitative analysis of relationships between the number of
homicides, population size and other ten urban metrics. By using data from
Brazilian cities, we show that well defined average scaling laws with the
population size emerge when investigating the relations between population and
number of homicides as well as population and urban metrics. We also show that
the fluctuations around the scaling laws are log-normally distributed, which
enabled us to model these scaling laws by a stochastic-like equation driven by
a multiplicative and log-normally distributed noise. Because of the scaling
laws, we argue that it is better to employ logarithms in order to describe the
number of homicides in function of the urban metrics via regression analysis.
In addition to the regression analysis, we propose an approach to correlate
crime and urban metrics via the evaluation of the distance between the actual
value of the number of homicides (as well as the value of the urban metrics)
and the value that is expected by the scaling law with the population size.
This approach have proved to be robust and useful for unveiling
relationships/behaviors that were not properly carried out by the regression
analysis, such as i) the non-explanatory potential of the elderly population
when the number of homicides is much above or much below the scaling law, ii)
the fact that unemployment has explanatory potential only when the number of
homicides is considerably larger than the expected by the power law, and iii) a
gender difference in number of homicides, where cities with female population
below the scaling law are characterized by a number of homicides above the
power law.Comment: Accepted for publication in PLoS ON
Scale-adjusted metrics for predicting the evolution of urban indicators and quantifying the performance of cities
More than a half of world population is now living in cities and this number
is expected to be two-thirds by 2050. Fostered by the relevancy of a scientific
characterization of cities and for the availability of an unprecedented amount
of data, academics have recently immersed in this topic and one of the most
striking and universal finding was the discovery of robust allometric scaling
laws between several urban indicators and the population size. Despite that,
most governmental reports and several academic works still ignore these
nonlinearities by often analyzing the raw or the per capita value of urban
indicators, a practice that actually makes the urban metrics biased towards
small or large cities depending on whether we have super or sublinear
allometries. By following the ideas of Bettencourt et al., we account for this
bias by evaluating the difference between the actual value of an urban
indicator and the value expected by the allometry with the population size. We
show that this scale-adjusted metric provides a more appropriate/informative
summary of the evolution of urban indicators and reveals patterns that do not
appear in the evolution of per capita values of indicators obtained from
Brazilian cities. We also show that these scale-adjusted metrics are strongly
correlated with their past values by a linear correspondence and that they also
display crosscorrelations among themselves. Simple linear models account for
31%-97% of the observed variance in data and correctly reproduce the average of
the scale-adjusted metric when grouping the cities in above and below the
allometric laws. We further employ these models to forecast future values of
urban indicators and, by visualizing the predicted changes, we verify the
emergence of spatial clusters characterized by regions of the Brazilian
territory where we expect an increase or a decrease in the values of urban
indicators.Comment: Accepted for publication in PLoS ON
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Polyamide Nanocomposites for Selective Laser Sintering
Current polyamide 11 and 12 are lacking in fire retardancy and high strength/high
heat resistance characteristics for a plethora of finished parts that are desired and required
for performance driven applications. It is anticipated that nanomodification of polyamide
11 and 12 will result in enhanced polymer performance, i.e., fire retardancy, high strength
and high heat resistance for polyamide 11 and 12. It is expected that these findings will
expand the market opportunities for polyamide 11 and 12 resin manufacturers.
The objective of this research is to develop improved polyamide 11 and 12 polymers
with enhanced flame retardancy, thermal, and mechanical properties for selective laser
sintering (SLS) rapid manufacturing (RM). A nanophase was introduced into the
polyamide 11 and 12 via twin screw extrusion to provide improved material properties of
the polymer blends. Arkema RILSAN® polyamide 11 molding polymer pellets and
Degussa VESTAMID® L1670 polyamide 12 were examined with three types of
nanoparticles: chemically modified montmorillonite (MMT) organoclays, surface
modified nanosilica, and carbon nanofibers (CNFs) to create polyamide 11 and 12
nanocomposites.
Wide angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM)
were used to determine the degree of dispersion. Injection molded test specimens were
fabricated for physical, thermal, mechanical properties, and flammability tests. Thermal
stability of these polyamide 11 and 12 nanocomposites was examined by TGA.
Mechanical properties such as tensile, flexural, and elongation at break were measured.
Flammability properties were also obtained using the Cone Calorimeter at an external
heat flux of 50 kW/m2. TEM micrographs, physical, mechanical, and flammability
properties are included in the paper. Polyamide 11 and 12 nanocomposites properties are
compared with polyamide 11 and 12 baseline polymers. Based on flammability and
mechanical material performance, selective polymers including polyamide 11
nanocomposites and control polyamide 11 were cryogenically ground into fine powders
and fabricated into SLS parts.Mechanical Engineerin
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