Abstract: Water suspensions of in-organic (metals and oxides)
and organic nano-objects (chitozan and collagen) were subjected to
the treatment of direct and alternative electrical fields. In addition to
quasi-periodical spatial patterning resonance-like performance of
spatial distributions of these suspensions has been found at low
frequencies of alternating electrical field. These resonances are
explained as the result of creation of equilibrium states of groups of
charged nano-objects with opposite signs of charges at the interparticle
distances where the forces of Coulomb attraction are
compensated by the repulsion forces induced by relatively negative
polarization of hydrated regions surrounding the nanoparticles with
respect to pure water. The low frequencies of these resonances are
explained by comparatively big distances between the particles and
their big masses with t\respect to masses of atoms constituting
molecules with high resonance frequencies. These new resonances
open a new approach to detailed modeling and understanding of
mechanisms of the influence of electrical fields on the functioning of
internal organs of living organisms at the level of cells and neurons.
Abstract: Knowledge transfer between personnel could benefit an organization’s improved competitive advantage in the marketplace from a strategic approach to knowledge management. The lack of information sharing between personnel could create knowledge transfer gaps while restricting the decision-making processes. Knowledge transfer between personnel can potentially improve information sharing based on an implemented knowledge management strategy. An organization’s capacity to gain more knowledge is aligned with the organization’s prior or existing captured knowledge. This case study attempted to understand the overall influence of a KMS within the corporate environment and knowledge exchange between personnel. The significance of this study was to help understand how organizations can improve the Return on Investment (ROI) of a knowledge management strategy within a knowledge-centric organization. A qualitative descriptive case study was the research design selected for this study. The lack of information sharing between personnel may create knowledge transfer gaps while restricting the decision-making processes. Developing a knowledge management strategy acceptable at all levels of the organization requires cooperation in support of a common organizational goal. Working with management and executive members to develop a protocol where knowledge transfer becomes a standard practice in multiple tiers of the organization. The knowledge transfer process could be measurable when focusing on specific elements of the organizational process, including personnel transition to help reduce time required understanding the job. The organization studied in this research acknowledged the need for improved knowledge management activities within the organization to help organize, retain, and distribute information throughout the workforce. Data produced from the study indicate three main themes including information management, organizational culture, and knowledge sharing within the workforce by the participants. These themes indicate a possible connection between an organizations KMS, the organizations culture, knowledge sharing, and knowledge transfer.
Abstract: This paper presents results of numerical and experimental studies on a two-dimensional (2D) flapping elliptic airfoil in a forward flight condition at Reynolds number of 5000. The study is motivated from an earlier investigation which shows that the deterioration in thrust performance of a sinusoidal heaving and pitching 2D (NACA0012) airfoil at high flapping frequency can be recovered by changing the effective angle of attack profile to square wave, sawtooth, or cosine wave shape. To better understand why such modifications lead to superior thrust performance, we take a closer look at the transient aerodynamic force behavior of an airfoil when the effective angle of attack profile changes gradually from a generic smooth trapezoidal profile to a sinusoid shape by modifying the base length of the trapezoid. The choice of using a smooth trapezoidal profile is to avoid the infinite acceleration condition encountered in the square wave profile. Our results show that the enhancement in the time-averaged thrust performance at high flapping frequency can be attributed to the delay and reduction in the drag producing valley region in the transient thrust force coefficient when the effective angle of attack profile changes from sinusoidal to trapezoidal.
Abstract: Sun tracking systems are the systems following the sun ray by a right angle or by predetermined certain angle. In this study, we used theoretical trajectory of sun for latitude of central Anatolia in Turkey. A two degree of freedom spherical mechanism was designed to have a large workspace able to follow the sun's theoretical motion by the right angle during the whole year. An inverse kinematic analysis was generated to find the positions of mechanism links for the predicted trajectory. Force and torque analysis were shown for the first day of the year.
Abstract: Liquid storage tanks have become widespread during the recent decades due to their extensive usage. Analysis of liquid containing tanks is known to be complex due to hydrodynamic force exerted on tank which makes the analysis a complex one. The objective of this research is to carry out analysis of liquid domain along with structural interaction for various geometries of circular tanks considering seismic effects. An attempt has been made to determine hydrodynamic pressure distribution on the tank wall considering impulsive and convective components of liquid mass. To get a better picture, a comparative study of Draft IS 1893 Part 2, ACI 350.3 and Eurocode 8 for Circular Shaped Tank has been performed. Further, the differences in the magnitude of shear and moment at base as obtained from static (IS 3370 IV) and dynamic (Draft IS 1892 Part 2) analysis of ground supported circular tank highlight the need for us to mature from the old code to a newer code, which is more accurate and reliable.
Abstract: Present study focused on the utilization of solar
energy by the help of photovoltaic greenhouse solar dryer under
forced mode. A single slope photovoltaic greenhouse solar dryer has
been proposed and thermal modelling has been developed. Various
parameters have been calculated by thermal modelling such as
greenhouse room temperature, cell temperature, crop temperature and
air temperature at exit of greenhouse. Further cell efficiency, thermal
efficiency, and overall thermal efficiency have been calculated for a
typical day of May and November. It was found that system can
generate equivalent thermal energy up to 7.65 kW and 6.66 kW per
day for clear day of May and November respectively.
Abstract: Solar water heating is a thermodynamic process of
heating water using sunlight with the help of solar water heater. Thus,
solar water heater is a device used to harness solar energy. In this
paper, a modified solar water heating system (MSWHS) has been
proposed over flat plate collector (FPC) and Evacuated tube collector
(ETC). The modifications include selection of materials other than
glass, and glass wool which are conventionally used for fabricating
FPC and ETC. Some modifications in design have also been
proposed. Its collector is made of double layer of semi-cylindrical
acrylic tubes and fibre reinforced plastic (FRP) insulation base. Water
tank is made of double layer of acrylic sheet except base and north
wall. FRP is used in base and north wall of the water tank. A concept
of equivalent thickness has been utilised for calculating the
dimensions of collector plate, acrylic tube and tank. A thermal model for the proposed design of MSWHS is developed
and simulation is carried out on MATLAB for the capacity of 200L
MSWHS having collector area of 1.6 m2, length of acrylic tubes of
2m at an inclination angle 25° which is taken nearly equal to the
latitude of the given location. Latitude of Allahabad is 24.45° N. The
results show that the maximum temperature of water in tank and tube
has been found to be 71.2°C and 73.3°C at 17:00hr and 16:00hr
respectively in March for the climatic data of Allahabad. Theoretical performance analysis has been carried out by varying
number of tubes of collector, the tank capacity and climatic data for
given months of winter and summer.
Abstract: Sisal leaves were subjected to enzymatic retting
method to extract the sisal fibre. A portion of the fibre was pretreated
with alkali (NaOH), and further treated with benzoyl chloride
and silane treatment reagents. Both the treated and untreated Sisal
fibre composites were used to fabricate the composite by hand lay-up
technique using unsaturated polyester resin. Tensile, flexural, water
absorption, density, thickness swelling and chemical resistant tests
were conducted and evaluated on the composites. Results obtained
for all the parameters showed an increase in the treated fibre
compared to untreated fibre. FT-IR spectra results ascertained the
inclusion of benzoyl and silane groups on the fibre surface. Scanning
electron microscopy (SEM) result obtained showed variation in the
morphology of the treated and untreated fibre. Chemical modification
was found to improve adhesion of the fibre to the matrix, as well as
physico-mechanical properties of the composites.
Abstract: Reinforced earth structures are generally subjected to cyclic loading generated from earthquakes. This paper presents a summary of the results and analyses of a testing program carried out in a large-scale multi-function geosynthetic testing apparatus that accommodates soil samples up to 1.0 m3. This apparatus performs different shear and pullout tests under both static and cyclic loading. The testing program was carried out to investigate the controlling factors affecting soil/geogrid interaction under cyclic loading. The extensibility of the geogrids, the applied normal stresses, the characteristics of the cyclic loading (frequency, and amplitude), and initial static load within the geogrid sheet were considered in the testing program. Based on the findings of the testing program, the effect of these parameters on the pullout resistance of geogrids, as well as the displacement mobility under cyclic loading were evaluated. Conclusions and recommendations for the design of reinforced earth walls under cyclic loading are presented.
Abstract: The combination of multi–walled carbon nanotubes
(MWCNTs) with polymers offers an attractive route to reinforce the
macromolecular compounds as well as the introduction of new
properties based on morphological modifications or electronic
interactions between the two constituents. As they are only a few
nanometers in dimension, it offers ultra-large interfacial area per
volume between the nano-element and polymer matrix. Nevertheless,
the use of MWCNTs as a rough material in different applications has
been largely limited by their poor processability, insolubility, and
infusibility. Studies concerning the nanofiller reinforced polymer
composites are justified in an attempt to overcome these limitations.
This work presents one preliminary study of MWCNTs dispersion
into the PVDF homopolymer. For preparation, the composite
components were diluted in n,n-dimethylacetamide (DMAc) with
mechanical agitation assistance. After complete dilution, followed by
slow evaporation of the solvent at 60°C, the samples were dried.
Films of about 80 μm were obtained. FTIR and UV-Vis
spectroscopic techniques were used to characterize the
nanocomposites. The appearance of absorption bands in the FTIR
spectra of nanofilled samples, when compared to the spectrum of
pristine PVDF samples, are discussed and compared with the UV-Vis
measurements.
Abstract: High double excitation of two-electron atoms has been
investigated using hyperpherical coordinates within a modified
adiabatic expansion technique. This modification creates a novel
fictitious force leading to a spontaneous exchange symmetry breaking
at high double excitation. The Pauli principle must therefore be
regarded as approximation valid only at low excitation energy.
Threshold electron scattering from high Rydberg states shows an
unexpected time reversal symmetry breaking. At threshold for double
escape we discover a broad (few eV) Cooper pair.
Abstract: Reinforced cement concrete is getting extensively used
for construction of different type of structures for the last one century.
During this period, we have constructed many structures like
buildings, bridges, industrial structures, pavement, water tanks etc.
using this construction material. These structures have been created
with huge investment of resources. It is essential to maintain those
structures in functional condition. Since deterioration in RCC
Structures is a common and natural phenomenon it is required to have
a detailed plan, methodology for structural repair and rehabilitation
shall be in place for dealing such issues. It is important to know exact
reason of distress, type of distress and correct method of repair
concrete structures. The different methods of repair are described in
paper according to distress category which can be refereed for repair.
Major finding of the study is that to protect our structure we need to
have maintenance frequency and correct material to be chosen for
repair. Also workmanship during repair needs to be taken utmost care
for quality repair.
Abstract: Ultrasonic metal welding has been the subject of ongoing research and development, most recently concentrating on metal joining in miniature devices, for example to allow solder-free wire bonding. As well as at the small scale, there are also opportunities to research the joining of thicker sheet metals and to widen the range of similar and dissimilar materials that can be successfully joined using this technology. This study presents the design, characterisation and test of a lateral-drive ultrasonic metal spot welding device. The ultrasonic metal spot welding horn is modelled using finite element analysis (FEA) and its vibration behaviour is characterised experimentally to ensure ultrasonic energy is delivered effectively to the weld coupon. The welding stack and fixtures are then designed and mounted on a test machine to allow a series of experiments to be conducted for various welding and ultrasonic parameters. Weld strength is subsequently analysed using tensile-shear tests. The results show how the weld strength is particularly sensitive to the combination of clamping force and ultrasonic vibration amplitude of the welding tip, but there are optimal combinations of these and also limits that must be clearly identified.
Abstract: The objective of this research is to develop a general technique so that one may predict the dynamic behaviour of a three-dimensional scale crane model subjected to time-dependent moving point forces by means of conventional finite element computer packages. To this end, the whole scale crane model is divided into two parts: the stationary framework and the moving substructure. In such a case, the dynamic responses of a scale crane model can be predicted from the forced vibration responses of the stationary framework due to actions of the four time-dependent moving point forces induced by the moving substructure. Since the magnitudes and positions of the moving point forces are dependent on the relative positions between the trolley, moving substructure and the stationary framework, it can be found from the numerical results that the time histories for the moving speeds of the moving substructure and the trolley are the key factors affecting the dynamic responses of the scale crane model.
Abstract: This paper investigates the application of metallic
coatings on high fiber volume fraction carbon/epoxy polymer matrix
composites. For the grip of the metallic layer, a method of modifying
the surface of the composite by introducing a mixture of copper and
steel powder (filler powders) which can reduce the impact of thermal
spray particles. The powder was introduced to the surface at the time
of the forming. Arc spray was used to project the zinc coating layer.
The substrate was grit blasted to avoid poor adherence. The porosity, microstructure, and morphology of layers are
characterized by optical microscopy, SEM and image analysis. The
samples were studied also in terms of hardness and erosion resistance.
This investigation did not reveal any visible evidence damage to the
substrates. The hardness of zinc layer was about 25.94 MPa and the
porosity was around (∼6.70%). The erosion test showed that the zinc
coating improves the resistance to erosion. Based on the results
obtained, we can conclude that thermal spraying allows the production
of protective coating on PMC. Zinc coating has been identified as a
compatible material with the substrate. The filler powders layer
protects the substrate from the impact of hot particles and allows
avoiding the rupture of brittle carbon fibers.
Abstract: Open jet testing is a valuable testing technique which
provides the desired results with reasonable accuracy. It has been
used in past for the airships and now has recently been applied for the
hybrid ones, having more non-buoyant force coming from the wings,
empennage and the fuselage. In the present review work, an effort
has been done to review the challenges involved in open jet testing.
In order to shed light on the application of this technique, the
experimental results of two different configurations are presented.
Although, the aerodynamic results of such vehicles are unique to its
own design; however, it will provide a starting point for planning any
future testing. Few important testing areas which need more attention
are also highlighted. Most of the hybrid buoyant aerial vehicles are
unconventional in shape and there experimental data is generated,
which is unique to its own design.
Abstract: This paper discusses the applicability of the numerical model for a damage prediction method of the accidental hydrogen explosion occurring in a hydrogen facility. The numerical model was based on an unstructured finite volume method (FVM) code “NuFD/FrontFlowRed”. For simulating unsteady turbulent combustion of leaked hydrogen gas, a combination of Large Eddy Simulation (LES) and a combustion model were used. The combustion model was based on a two scalar flamelet approach, where a G-equation model and a conserved scalar model expressed a propagation of premixed flame surface and a diffusion combustion process, respectively. For validation of this numerical model, we have simulated the previous two types of hydrogen explosion tests. One is open-space explosion test, and the source was a prismatic 5.27 m3 volume with 30% of hydrogen-air mixture. A reinforced concrete wall was set 4 m away from the front surface of the source. The source was ignited at the bottom center by a spark. The other is vented enclosure explosion test, and the chamber was 4.6 m × 4.6 m × 3.0 m with a vent opening on one side. Vent area of 5.4 m2 was used. Test was performed with ignition at the center of the wall opposite the vent. Hydrogen-air mixtures with hydrogen concentrations close to 18% vol. were used in the tests. The results from the numerical simulations are compared with the previous experimental data for the accuracy of the numerical model, and we have verified that the simulated overpressures and flame time-of-arrival data were in good agreement with the results of the previous two explosion tests.
Abstract: In the aviation industry, many faults may occur frequently during the maintenance processes and assembly operations of complex structured aircrafts because of their high dependencies of components. These faults affect the quality of aircraft parts or developed modules adversely. Technical employee requires long time and high labor force while checking the correctness of each component. In addition, the person must be trained regularly because of the ever-growing and changing technology. Generally, the cost of this training is very high. Augmented Reality (AR) technology reduces the cost of training radically and improves the effectiveness of the training. In this study, the usage of AR technology in the aviation industry has been investigated and the effectiveness of AR with heads-up display glasses has been examined. An application has been developed for comparison of production process with AR and manual one.
Abstract: Ant algorithms are well-known metaheuristics which
have been widely used since two decades. In most of the literature,
an ant is a constructive heuristic able to build a solution from scratch.
However, other types of ant algorithms have recently emerged: the
discussion is thus not limited by the common framework of the
constructive ant algorithms. Generally, at each generation of an ant
algorithm, each ant builds a solution step by step by adding an
element to it. Each choice is based on the greedy force (also called the
visibility, the short term profit or the heuristic information) and the
trail system (central memory which collects historical information of
the search process). Usually, all the ants of the population have the
same characteristics and behaviors. In contrast in this paper, a new
type of ant metaheuristic is proposed, namely SMART (for Solution
Methods with Ants Running by Types). It relies on the use of different
population of ants, where each population has its own personality.
Abstract: For several hundred years, the design of railway tracks
has practically remained unchanged. Traditionally, rail tracks are
placed on a ballast layer due to several reasons, including economy,
rapid drainage, and high load bearing capacity. The primary function
of ballast is to distributing dynamic track loads to sub-ballast and
subgrade layers, while also providing lateral resistance and allowing
for rapid drainage. Upon repeated trainloads, the ballast becomes
fouled due to ballast degradation and the intrusion of fines which
adversely affects the strength and deformation behaviour of ballast.
This paper presents the use of three-dimensional discrete element
method (DEM) in studying the shear behaviour of the fouled ballast
subjected to direct shear loading. Irregularly shaped particles of
ballast were modelled by grouping many spherical balls together in
appropriate sizes to simulate representative ballast aggregates. Fouled
ballast was modelled by injecting a specified number of miniature
spherical particles into the void spaces. The DEM simulation
highlights that the peak shear stress of the ballast assembly decreases
and the dilation of fouled ballast increases with an increase level of
fouling. Additionally, the distributions of contact force chain and
particle displacement vectors were captured during shearing progress,
explaining the formation of shear band and the evolutions of
volumetric change of fouled ballast.