263 research outputs found
The effect of particulate strengthening on microstructure and mechanical characterization of binary-modified composites on mild steel
This article presents the microstructure, tribological behavior, and hardness properties of the Zn-TiO2 functional
composite coating produced using electrolytic co-deposition technique. The 7.0–13.0 weight fractions of Ti particles
were incorporated in a Zn bath to form Zn-TiO2 alloy in the presence of other additives. The microstructural properties
of the fabricated coating were investigated using a scanning electron microscope equipped with an energy-dispersive
spectroscope, X-ray diffraction, and an atomic force microscope. The anticorrosion behavior in 3.65% NaCl medium was studied using potentiodynamic polarization technique and characterized using high-resolution optical microscope. The
hardness and wear properties of the coated alloys were measured with high diamond microhardness tester and
reciprocating sliding tester, respectively. From the results, the increases in hardness and wear resistance are attributed to the formation of the incorporated particulate and uniform precipitation of the metal grains at the metal lattice. The contribution of TiO2 particles especially with Zn-13Ti-0.3 V-S provides new orientation of metal–matrix-modified coated structure and decrease in friction coefficient. The anticorrosion resistance characteristics were found to improve significantly in response to concentration of additive
Estimation of Parameters in DNA Mixture Analysis
In Cowell et al. (2007), a Bayesian network for analysis of mixed traces of
DNA was presented using gamma distributions for modelling peak sizes in the
electropherogram. It was demonstrated that the analysis was sensitive to the
choice of a variance factor and hence this should be adapted to any new trace
analysed. In the present paper we discuss how the variance parameter can be
estimated by maximum likelihood to achieve this. The unknown proportions of DNA
from each contributor can similarly be estimated by maximum likelihood jointly
with the variance parameter. Furthermore we discuss how to incorporate prior
knowledge about the parameters in a Bayesian analysis. The proposed estimation
methods are illustrated through a few examples of applications for calculating
evidential value in casework and for mixture deconvolution
Effect of WO3 Nanoparticle Loading on the Microstructural, Mechanical and Corrosion Resistance of Zn Matrix/TiO2-WO3 Nanocomposite Coatings for Marine Application
In this study, for marine application purposes, we
evaluated the effect of process parameter and particle loading on
the microstructure, mechanical reinforcement and corrosion
resistance properties of a Zn-TiO2-WO3 nanocomposite produced
via electrodeposition. We characterized the morphological
properties of the composite coatings with a Scanning Electron
Microscope (SEM) equipped with an Energy Dispersive
Spectrometer (EDS). We carried out mechanical examination using
a Dura Scan hardness tester and a CERT UMT-2 multi-functional
tribological tester. We evaluated the corrosion properties by linear
polarization in 3.5% NaCl. The results show that the coatings
exhibited good stability and the quantitative particle loading greatly
enhanced the structural and morphological properties, hardness
behavior and corrosion resistance of the coatings. We observed the
precipitation of this alloy on steel is greatly influenced by the
composite characteristics
Surface modification, strengthening effect and electrochemical comparative study of Zn-Al2O3-CeO3 and Zn-TiO2-CeO3 coating on mild steel
Surface enhancement of engineering materials is
necessary for preventing service failure and corrosion attacks
industrially. The surface modification, strengthening effect
and electrochemical comparative study of Zn-Al2O3-CeO3
and Zn-TiO2-CeO3 coating on mild steel was investigated.
Deposition was performed to obtain a better surface adherent
coating using the electrodeposition technique. Co-deposition
of mild steel resulted into surface modification attributes to
the complex alloys that were developed. Films of mild steel
were electrodeposited on zinc electrodes using the chloride
bath solutions. The effect of deposition potentials was systematically
studied using a focus ion beam scanning electron
microscope (FIB-SEM) and an atomic force microscope
(AFM) to observe the surface morphology, topography and
the surface adherent properties of the coatings. The elemental
composition and the phases evolved in composite coatings were measured by means of the energy dispersed
spectrometer (EDS). The microhardness measurements and
corrosion behaviours of the deposits were investigated.
Weight loss measurement was conducted on the plated samples
to observe the rate of corrosion and it was observed that
there was severe corrosion on the controlled sample in comparison
to the plated samples and that Zn-TiO2-CeO3
resisted more corrosion attacks
Performance Evaluation Effect of Nb2O5 Particulate on the Microstructural, Wear and Anti-corrosion Resistance of Zn–Nb2O5 Coatings on Mild Steel for Marine Application
In this study, we developed Zn–Nb2O5 composite
coatings from sulfate bath for wear and corrosion performance
on mild steel by electrodeposition technique. The
effect of Nb2O5 particulate on the Zn–Nb2O5 properties was
investigated. The particle volume fraction was varied within
between 10 and 20 wt%. The structural properties of the
composite coatings were characterized using scanning
electron microscope equipped with energy-dispersive spectrometer.
The hardness and wear of the composite coating
were measured with diamond base microhardness indenter
tester and sliding CETR reciprocating wear testers, respectively.
The corrosion properties were examined in 3.65%
NaCl using AUTOLAB 101 Metrohm potentiostat–galvanostat
with linear polarization technique. The results
showed that average hardness value of 192.6 and 200.6 HV
and passivation potential of 4.39E?08 and 5.30E?08(X)
were obtained for the 10–20 wt% Nb2O5 particulate on the
Zn–Nb2O5 coatings. The wear performance improves by
63.4% as against the control sample. In all, this study
established that up to 20 wt% of Nb2O5 in Zn–Nb2O5 composite coating significant corrosion, wear and microhardness
propagation resistance of mild steel was attained
Chemical interaction, interfacial effect and the microstructural characterization of the induced zinc–aluminum–Solanum tuberosum in chloride solution on mild steel
In this study, we report the effect of Solanum tuberosum (ST) as a strong
additive on the morphological interaction, wear, and hardness properties of electroplated
zinc coating in chloride bath solutions. The structural and the mechanical
behavior of the Zn–Al–ST coating were studied and compared with the properties of
Zn coatings. Characterization of the electrodeposited coatings were carried out
using scanning electron microscopy, energy dispersive spectrometer, AFM, and
X-ray diffraction techniques. The adhesion between the coatings and substrate was
examined mechanically using hardness and wear techniques. From the results,
amorphous Zn–Al–ST coatings were effectively obtained by electrodeposition using
direct current. The coating morphology was revealed to be reliant on the bath
composition containing strong leveling additives. From all indications, ST content
contribute to a strong interfacial surface effect leading to crack-free and better
morphology, good hardness properties, and improved wear resistance due to the
precipitation of Zn2Si and Zn7Al2Si3. Hence, addition of ST is beneficial for the
structural strengthening, hardness, and wear resistance properties of such coatings
Visitor expenditure estimation for grocery store location planning: a case study of Cornwall
Visitor expenditure is an important driver of demand in many local economies, supporting a range of services and facilities which may not be viable based solely on residential demand. In areas where self-catering accommodation is prevalent visitor demand makes up a considerable proportion of sales and revenue within grocery stores, yet this form of visitor consumption is commonly overlooked in supply and demand-side estimates of visitor spend. As such, store location planning in tourist resorts, decisions about local service provision and the local economic impacts of tourism are based on very limited demand-side estimates of visitor spend. Using Cornwall, South West England as a study area, we outline a methodology and data sources to estimate small-area visitor grocery spend. We use self-catering accommodation provision, utilisation and visitor expenditure rates as key factors driving visitor spend. We identify that the use of visitor accommodation accounts for the spatial and temporal complexities of visitor demand that may be overlooked when using alternative approaches, such as the up-scaling of residential demand. Using a spatial interaction model, we demonstrate that our expenditure estimates can be used to generate store level revenue estimation within tourist resorts, and we make a number of recommendations for service provision and store location planning in these areas
An experimental study of cathodic protection for chloride contaminated reinforced concrete
Cathodic protection (CP) is being increasingly used on reinforced concrete structures to protect steel reinforcing bars from corrosion in aggressive conditions. Due to the complexity of environmental conditions, the design specifications in national and international standards are still open to discussion to achieve both sufficient and efficient protection for reinforced concrete structures in engineering practices. This paper reports an experimental research to investigate the influence of chloride content on concrete resistivity, rebar corrosion rate and the performance of CP operation using different current densities. It aims to understand the correlation between the chloride content and concrete resistivity together with the CP current requirement, and to investigate the precision of the CP design criteria in standards
- …