Abstract: This paper presents a computational study of steady
state three dimensional very high turbulent flow and heat transfer
characteristics in a constant temperature-surfaced circular duct fitted
with 900 hemispherical inline baffles. The computations are based on
realizable k-ɛ model with standard wall function considering the
finite volume method, and the SIMPLE algorithm has been
implemented. Computational Study are carried out for Reynolds
number, Re ranging from 80000 to 120000, Prandtl Number, Pr of
0.73, Pitch Ratios, PR of 1,2,3,4,5 based on the hydraulic diameter of
the channel, hydrodynamic entry length, thermal entry length and the
test section. Ansys Fluent 15.0 software has been used to solve the
flow field. Study reveals that circular pipe having baffles has a higher
Nusselt number and friction factor compared to the smooth circular
pipe without baffles. Maximum Nusselt number and friction factor
are obtained for the PR=5 and PR=1 respectively. Nusselt number
increases while pitch ratio increases in the range of study; however,
friction factor also decreases up to PR 3 and after which it becomes
almost constant up to PR 5. Thermal enhancement factor increases
with increasing pitch ratio but with slightly decreasing Reynolds
number in the range of study and becomes almost constant at higher
Reynolds number. The computational results reveal that optimum
thermal enhancement factor of 900 inline hemispherical baffle is
about 1.23 for pitch ratio 5 at Reynolds number 120000.It also shows
that the optimum pitch ratio for which the baffles can be installed in
such very high turbulent flows should be 5. Results show that pitch
ratio and Reynolds number play an important role on both fluid flow
and heat transfer characteristics.
Abstract: Experts, enterprises and operators expect that the
bandwidth request will increase up to rates of 100 to 1,000 Mbps
within several years. Therefore the most important question is which
technology shall satisfy the future consumer broadband demands.
Currently the consensus is, that the fiber technology has the best
technical characteristics to achieve such the high bandwidth rates.
But fiber technology is so far very cost-intensive and resource
consuming. To avoid these investments, operators are concentrating
to upgrade the existing copper and hybrid fiber coax infrastructures.
This work presents a comparison of the copper and fiber
technologies including an overview about the current German
broadband market. Both technologies are reviewed in the terms of
demand, willingness to pay and economic efficiency in connection
with the technical characteristics.
Abstract: The heavy metal pollution of the soils around the mining area near Shamlugh town and related risks to human health were assessed. The investigations showed that the soils were polluted with heavy metals that can be ranked by anthropogenic pollution degree as follows: Cu>Pb>As>Co>Ni>Zn. The main sources of the anthropogenic metal pollution of the soils were the copper mining area near Shamlugh town, the Chochkan tailings storage facility and the trucks transferring ore from the mining area. Copper pollution degree in some observation sites was unallowable for agricultural production. The total non-carcinogenic chronic hazard index (THI) values in some places, including observation sites in Shamlugh town, were above the safe level (THI
Abstract: Biodiesel as an alternative diesel fuel is steadily gaining more attention and significance. However, there are some drawbacks while using biodiesel regarding its properties that requires it to be blended with petrol based diesel and/or additives to improve the fuel characteristics. This study analyses thermal cracking as an alternative technology to improve biodiesel characteristics in which, FAME based biodiesel produced by transesterification of castor oil is fed into a continuous thermal cracking reactor at temperatures range of 450-500°C and flowrate range of 20-40 g/hr. Experiments designed by response surface methodology and subsequent statistical studies show that temperature and feed flowrate significantly affect the products yield. Response surfaces were used to study the impact of temperature and flowrate on the product properties. After each experiment, the produced crude bio-oil was distilled and diesel cut was separated. As shorter chain molecules are produced through thermal cracking, the distillation curve of the diesel cut fitted more with petrol based diesel curve in comparison to the biodiesel. Moreover, the produced diesel cut properties adequately pose within property ranges defined by the related standard of petrol based diesel. Cold flow properties, high heating value as the main drawbacks of the biodiesel are improved by this technology. Thermal cracking decreases kinematic viscosity, Flash point and cetane number.
Abstract: Rapidly changing factors that affect daily life also affect operational environment and the way military leaders fulfill their missions. With the help of technological developments, traditional linearity of conflict and war has started to fade away. Furthermore, mission domain has broadened to include traditional threats, hybrid threats and new challenges of cyber and space. Considering the future operational environment, future military leaders need to adapt themselves to the new challenges of the future battlefield. But how to decide what kind of features of leadership are required to operate and accomplish mission in the new complex battlefield? In this article, the main aim is to provide answers to this question. To be able to find right answers, first leadership and leadership components are defined, and then characteristics of future operational environment are analyzed. Finally, leadership features that are required to be successful in redefined battlefield are explained.
Abstract: Complex lifting entry was selected for precise landing
performance during the Mars Science Laboratory entry. This study
aims to develop the three-dimensional numerical method for precise
computation and the surface panel method for rapid engineering
prediction. Detailed flow field analysis for Mars exploration mission
was performed by carrying on a series of fully three-dimensional
Navier-Stokes computations. The static aerodynamic performance was
then discussed, including the surface pressure, lift and drag coefficient,
lift-to-drag ratio with the numerical and engineering method.
Computation results shown that the shock layer is thin because of
lower effective specific heat ratio, and that calculated results from both
methods agree well with each other, and is consistent with the
reference data. Aerodynamic performance analysis shows that CG
location determines trim characteristics and pitch stability, and certain
radially and axially shift of the CG location can alter the capsule lifting
entry performance, which is of vital significance for the aerodynamic
configuration design and inner instrument layout of the Mars entry
capsule.
Abstract: Exploration and exploitation capabilities are both
important within Operations as means for improvement when
managed separately, and for establishing dynamic improvement
capabilities when combined in balance. However, it is unclear what
exploration and exploitation capabilities imply in improvement and
development work within an Operations context. So, in order to
better understand how to develop exploration and exploitation
capabilities within Operations, the main characteristics of these
constructs needs to be identified and further understood. Thus, the
objective of this research is to increase the understanding about
exploitation and exploration characteristics, to concretize what they
translates to within the context of improvement and development
work in an Operations unit, and to identify practical challenges. A
literature review and a case study are presented. In the literature
review, different interpretations of exploration and exploitation are
portrayed, key characteristics have been identified, and a deepened
understanding of exploration and exploitation characteristics is
described. The case in the study is an Operations unit, and the aim is
to explore to what extent and in what ways exploration and
exploitation activities are part of the improvement structures and
processes. The contribution includes an identification of key
characteristics of exploitation and exploration, as well as an
interpretation of the constructs. Further, some practical challenges are
identified. For instance, exploration activities tend to be given low
priority, both in daily work as in the manufacturing strategy. Also,
the overall understanding about the concepts of exploitation and
exploration (or any similar aspect of dynamic improvement
capabilities) is very low.
Abstract: This study was aimed to investigate the machining
stability of a spindle tool with different preloaded amount. To this end,
the vibration tests were conducted on the spindle unit with different
preload to assess the dynamic characteristics and machining stability
of the milling machine. Current results demonstrate that the tool tip
frequency response characteristics and the machining stabilities in X
and Y direction are affected to change due to the different preload of
spindle bearings. As found from the results, a high preloaded spindle
tool shows higher limited cutting depth at mid position, while a spindle
with low preload shows a higher limited depth. This indicates that the
machining stability of a milling machine is affected to vary by the
spindle unit when it was assembled with different bearing preload.
Abstract: Nowadays, the main goal for modern horticultural
production is an increase the quality. In recent years, the use of
organic fertilizers or biostimulants that can be applied in agriculture
to improve quali-quantitative crop yields has encountered increasing
interest. Biostimulants are gaining importance also for their possible
use in organic and sustainable agriculture, to avoid excessive
fertilizer applications. Consecutive experimental trials were carried
out in the Apulia region (southern Italy) on three herbaceous crops
(cauliflower, pepper, fennel) grown in pots under conventional and
organic fertilization systems without and with biostimulants. The aim
was to determine the effects of three biostimulants (Siapton®10L,
Micotech L, Lysodin Alga-Fert) on quali-quantitative yield
characteristics. At harvest, the quali-quantitative yield characteristics
of each crop were determined. All of the experimental data were
subjected to analysis of variance (ANOVA), and when significant
effects were detected, the means were compared using Tukey’s tests.
These data show large differences in these yield characteristics
between conventional and organic crops, particularly highlighting
higher yields for the conventional crops, while variable results were
generally observed when the biostimulants were applied. In this
context, there were no effects of the biostimulants on the quantitative
yield, whereas there were low positive effects on the qualitative
characteristics, as related to higher dry matter content of cauliflower,
and higher soluble solids content of pepper. Moreover, there were
evident positive effects of the biostimulants with fennel, due to the
lower nitrate content. These latter data are in line with most of the
published literature obtained for other herbaceous crops.
Abstract: In this paper, the dependence of soliton pulses with
respect to phase in a 10Gbps, single channel, dispersion
uncompensated telecommunication system was studied. The
characteristic feature of periodic soliton interaction was noted at the
Interaction point (I=6202.5Km) in one collision length of L=12405.1
Km. The interaction point is located for 10Gbps system with an
initial relative spacing (qo) of soliton as 5.28 using Perturbation
theory. It is shown that, when two in-phase solitons are launched,
they interact at the point I=6202.5 Km, but the interaction could be
restricted with introduction of different phase initially. When the
phase of the input solitons increases, the deviation of soliton pulses at
the ‘I’ also increases. We have successfully demonstrated this effect
in a telecommunication set-up in terms of Quality factor (Q), where
the Q=0 for in-phase soliton. The Q was noted to be 125.9, 38.63,
47.53, 59.60, 161.37, and 78.04 for different phases such as 10o, 20o,
30o, 45o, 60o and 90o degrees respectively at Interaction point (I).
Abstract: Community integration is a construct that an
increasing body of research has shown to have a significant impact
on the wellbeing and recovery of people with psychiatric problems.
However, there are few studies that explore which factors can be
associated and predict community integration. Moreover, community
integration has been mostly studied in minority groups, and current
literature on the definition and manifestation of community
integration in the general population is scarcer. Thus, the current
study aims to characterize community integration and explore
possible predictor variables in a sample of participants with
psychiatric problems (PP, N=183) and a sample of participants from
the general population (GP, N=211).
Results show that people with psychiatric problems present above
average values of community integration, but are significantly lower
than their healthy counterparts. It was also possible to observe that
community integration does not vary in terms of the sociodemographic
characteristics of both groups in this study. Correlation
and multiple regression showed that, among several variables that
literature present as relevant in the community integration process,
only three variables emerged as having the most explanatory value in
community integration of both groups: sense of community, basic
needs satisfaction and submission. These results also shown that
those variables have increased explanatory power in the PP sample,
which leads us to emphasize the need to address this issue in future
studies and increase the understanding of the factors that can be
involved in the promotion of community integration, in order to
devise more effective interventions in this field.
Abstract: This paper deals with the study of reflection and
transmission characteristics of acoustic waves at the interface of a
semiconductor half-space and elastic solid. The amplitude ratios
(reflection and transmission coefficients) of reflected and transmitted
waves to that of incident wave varying with the incident angles have
been examined for the case of quasi-longitudinal wave. The special
cases of normal and grazing incidence have also been derived with
the help of Gauss elimination method. The mathematical model
consisting of governing partial differential equations of motion and
charge carriers’ diffusion of n-type semiconductors and elastic solid
has been solved both analytically and numerically in the study. The
numerical computations of reflection and transmission coefficients
has been carried out by using MATLAB programming software for
silicon (Si) semiconductor and copper elastic solid. The computer
simulated results have been plotted graphically for Si
semiconductors. The study may be useful in semiconductors,
geology, and seismology in addition to surface acoustic wave (SAW)
devices.
Abstract: Any variation in environmental characteristics of
geomorphosites would lead to destabilisation of their geotouristic
values all around the planet. The Urmia lake, with an area of
approximately 5,500 km2 and a catchment area of 51,876 km2, and to
which various reasons over time, especially in the last fifty years
have seen a sharp decline and have decreased by about 93 % in two
recent decades. These variations are not only driving significant
changes in the morphology and ecology of the present lake
landscape, but at the same time are shaping newly formed
morphologies, which vanished some valuable geomorphosites or
develop into smaller geomorphosites with significant value from a
scientific and cultural point of view. This paper analyses and
discusses features and evolution in several representative coastal and
island geomorphosites. For this purpose, a total of 23 geomorphosites
were studied in two data series (1963 and 2015) and the respective
data were compared and analysed. The results showed, the total loss
in geomorphosites area in a half century amounted to a loss of more
than 90% of the valuable geomorphosites. Moreover, the comparison
between the mean yearly value of coastal area lost over the entire
period and the yearly average calculated for the shorter period (1998-
2014) clearly indicates a pattern of acceleration. This acceleration in
the rate of reduction in lake area was seen in most of the southern
half of the lake. In the region as well, the general water-level falling
is not only causing the loss of a significant water resource, which is
followed by major impact on regional ecosystems, but is also driving
the most marked recent (last century) changes in the geotouristic
landscapes. In fact, the disappearance of geomorphosites means the
loss of tourism phenomenon. In this context attention must be paid to
the question of conservation. The action needed to safeguard
geomorphosites includes: 1) Preventive action, 2) Corrective action,
and 3) Sharing knowledge.
Abstract: Damage status of RC buildings is greatly influenced
by the characteristics of the imposed ground motion. Peak Ground
Acceleration and frequency contents are considered the main two
factors that affect ground motion characteristics; hence, affecting the
seismic response of RC structures and consequently their damage
state. A detailed investigation on the combined effects of these two
factors on damage assessment of RC buildings is carried out. Twenty
one earthquake records are analyzed and arranged into three groups,
according to their frequency contents. These records are used in an
investigation to define the expected damage state that would be
attained by RC buildings, if subjected to varying ground motion
characteristics. The damage assessment is conducted through
examining drift ratios and damage indices of the overall structure and
the significant structural components of RC building. Base and story
shear of RC building model, are also investigated, for cases when the
model is subjected to the chosen twenty one earthquake records.
Nonlinear dynamic analyses are performed on a 2-dimensional model
of a 12-story RC building.
Abstract: Auditory hallucinations among the most invalidating
and distressing experiences reported by patients diagnosed with
schizophrenia, leading to feelings of powerlessness and helplessness
towards their illness. In more severe cases, these auditory
hallucinations can take the form of commanding voices, which are
often related to high suicidality rates in these patients. Several
authors propose that the meanings attributed to the hallucinatory
experience, rather than characteristics like form and content, can be
determinant in patients’ reactions to hallucinatory activity,
particularly in the case of voice-hearing experiences. In this study, 48
patients diagnosed with paranoid schizophrenia presenting auditory
hallucinations were studied. Multiple regression analyses were
computed to study the influence of several developmental aspects,
such as family and social dynamics, bullying, depression, and sociocognitive
variables on the auditory hallucinations, on patients’
attributions and relationships with their voices, and on the resulting
invalidation of hallucinatory experience. Overall, results showed how
relationships with voices can mirror several aspects of interpersonal
relationship with others, and how self-schemas, depression and actual
social relationships help shaping the voice-hearing experience. Early
experiences of victimization and submission help predict the
attributions of omnipotence of the voices, and increased hostility
from parents seems to increase the malevolence of the voices,
suggesting that socio-cognitive factors can significantly contribute to
the etiology and maintenance of auditory hallucinations. The
understanding of the characteristics of auditory hallucinations and the
relationships patients established with their voices can allow the
development of more promising therapeutic interventions that can be
more effective in decreasing invalidation caused by this devastating
mental illness.
Abstract: The chemical and physical characteristics of rainwater
harvested from a typical rooftop were progressively studied. The
samples of rainwater collected were analyzed for pH, major ion
concentrations, TDS, turbidity, conductivity. All the Physicochemical
constituents fell within the WHO guideline limits at some points as
rainfall progresses except the pH. All the components of rainwater
quality measured during the study showed higher concentrations
during the early stages of rainfall and reduce as time progresses.
There was a downward trend in terms of pH as rain progressed, with
18% of the samples recording pH below the WHO limit of 6.5-8.0. It
was observed that iron concentration was above the WHO threshold
value of 0.3 mg/l on occasions of heavy rains. The results revealed
that most of physicochemical characteristics of rainwater samples
were generally below the WHO threshold, as such, the rainwater
characteristics showed satisfactory conditions in terms of
physicochemical constituents.
Abstract: Roles of the vegetation to mitigate the erosion of the
stream bed or to facilitate the deposition of the fine sediments by the
species of the aquatic plants were presented. Field investigation on the
estimation of the change of the bed level and the estimation of the flow
characteristics were performed. The results showed that Phragmites
japonica has the mitigation function of 0.3m-0.4m of the erosion in the
range of higher than 1.0m/s of flow velocity at the vegetated region.
Phragmites communis has the mitigation function of 0.2m-0.3m of the
erosion in the range of higher than 0.7m/s of flow velocity at the
vegetated region. Salix gracilistyla has greater role than Phragmites
japonica and Phragmites communis to sustain the stable channel. It
has the mitigation function of 0.4m-0.5m of the erosion in the range of
higher than 1.4m/s of flow velocity. Miscanthus sacchariflorus has a
weak role compared with that of Phragmites japonica and Salix
gracilistyla, but it has still function for sustaining the stable bed. From
these results, the vegetation has effective roles to mitigate the erosion
or to facilitate the deposition of the stream bed.
Abstract: In order to use bitumen in hot mix asphalt, it must
have specific characteristics. There are some methods to reach these
properties. Using polymer modifiers are one of the methods to
modify the bitumen properties. In this paper the effect of Styrene-
Butadiene-Rubber that is one of the bitumen polymer modifiers on
rheology properties of bitumen is studied. In this regard, the
rheological properties of base bitumen and the modified bitumen with
3, 4, and 5 percent of Styrene-Butadiene-Rubber (SBR) were
analysed. The results show that bitumen modified with 5 percent of
SBR has the best performance than the other samples.
Abstract: Heat transfer due to forced convection of copper water
based nanofluid has been predicted by Artificial Neural network
(ANN). The present nanofluid is formed by mixing copper
nanoparticles in water and the volume fractions are considered here
are 0% to 15% and the Reynolds number are kept constant at 100.
The back propagation algorithm is used to train the network. The
present ANN is trained by the input and output data which has been
obtained from the numerical simulation, performed in finite volume
based Computational Fluid Dynamics (CFD) commercial software
Ansys Fluent. The numerical simulation based results are compared
with the back propagation based ANN results. It is found that the
forced convection heat transfer of water based nanofluid can be
predicted correctly by ANN. It is also observed that the back
propagation ANN can predict the heat transfer characteristics of
nanofluid very quickly compared to standard CFD method.
Abstract: Mass media campaigns against obesity are often
designed to impact large audiences. This usually means that their
audience is defined based on general demographic characteristics like
age, gender, occupation etc., not taking into account psychographics
like behavior, motivations, wants, etc. Using psychographics, as the
base for the audience segmentation, is a common practice in case of
successful campaigns, as it allows developing more relevant
messages. It also serves a purpose of identifying key segments, those
that generate the best return on investment. For a health campaign,
that would be segments that have the best chance of being converted
into healthy lifestyle at the lowest cost. This paper presents the
limitations of the demographic targeting, based on the findings from
the reception study of IMSS (Mexican Social Security Institute) antiobesity
TV commercials and proposes mothers as the first level of
segmentation, in the process of identifying the key segment for these
campaigns.