bluuebunny/crossref_metadata_2025 huggingface dataset:
A Study of the Production of Glucose Syrup from Cassava Starch Using Acid Hydrolysis and the Preservation Using Sodium Bisulfite
Authors: Osemwengie Saint Osas , Omorodion S.N.E.
Published: September 2013

The production of glucose syrup from cassava starch using acid hydrolysis was carried out in this work. The analysis was based on the preservation of the produced glucose syrup using sodium bisulfite (NaHSO3). The concentration of the preservative was varied from 0.0ppm-30.0ppm (where ppm stands for amount of preservative in a million pert of sample). The ability of the preservative (sodium bisulfite) to sustain the shelf life of glucose syrup was investigated by studying its effects on the physiochemical properties (pH, moisture content, pour point, viscosity, specific gravity, and refractive index) of the glucose syrup. Four (4) different runs of experiment were performed within sixty-four (64) days, during which the physiochemical properties were closely monitored. Sample B1 which contain no sodium bisulfite could not retain the physiochemical properties. Sample B2 contain 5ppm of the preservative in the glucose syrup and shows a little stability of the physiochemical properties. The preservative ability of the sodium bisulfite on the glucose syrup was improved upon as the concentration in part per million increased (i.e from sample B3 to sample B4, from sample B4 to sample B5, in that order etc.). The optimum preservative ability was reached at sample B5 (which has 20.0ppm concentration of sodium bisulfite.) as the physiochemical properties was relatively maintained. Samples B6 and B7 (which have 25.0 and 30.0 part per million respectively) also show a stable preservative abilities. These samples that contain higher concentrations of sodium bisulfite after the optimum (that is, samples B6 andB7) which also yield stable preservative properties, should be discouraged because their intake could lead to health hazards, and the optimum preservative concentration should be encouraged.(That is, sample B5).
Electricity Generating Potential of Selected Landfill/Dumpsites in Rivers State, Nigeria
Authors: Ehirim Chiudo , Joel Ogbonna F.
Published: September 2013

The aim of this study was to estimate the electricity generating potential of three (3) dumpsites in specified locations of Obio/Akpor LGA of Rivers State, Nigeria using the Columbia Landfill Gas Model Version 1 developed for the United States Environmental Protection Agency Landfill Methane Outreach Programme (LMOP) as well as determine using the LMOP Landfill Gas Energy Benefits Calculator, the environmental/energy benefits of landfill gas to energy projects at the sites. The study involved literature review of waste management practice in the State, selection of study sites, consultation with relevant regulatory bodies in the State, field visits, waste burden quantification as well as data analysis. The findings from the study showed that two dumpsites have the potential to generate 0.5MW whilst the third dumpsite could generate 0.3MW of electricity if a comprehensive landfill gas collection system is installed in year 2015. Landfill gas energy projects of these sizes can provide power for about 500 homes. With rapid population growth in Port-Harcourt City and a corresponding increase in municipal waste generation, it is imperative to develop efficient landfill gas (LFG) to energy projects at landfills and dumpsites. This will not only reduce greenhouse gas emissions but improve local air quality, and control environmental pollution. The projects will also provide economic benefits to the community and the energy end user.
A Comparative Study of Biofuel and Fossil Fuel: A Case Study of Palm Oil and Crude Oil
Authors: Ugbebor J.N. , Membere E.A. , Joel O.J.
Published: September 2013

The cost benefit analysis and environmental pollution effects of biofuel (palm oil) and fossil fuel (crude oil) was studied. The study methodology included extensive literature review on relevant publications and laboratory analysis. Important parameters required for emission production and combustion such as CO, CH4, NOx, PM10, SOX and CO2 were analyzed. The combined total of emission production and combustion results indicated that biofuel and fossil fuel have 3.92 and 6.40 of CO; 0.98 and 1.05 of CH4; 25.23 and 27.54 of NOx, 0.00 and 0.67 of SOx, and 657 and 3564 of CO2 respectively. Other parameters considered in this study include fuel efficiency, environmental performance, cost benefits analysis and sustainability. From environmental performance comparison, the study indicated that 100% biofuel will cause reduction in greenhouse gases and other polluting emissions. It also indicated that use of palm oil as biofuel may have less impact on human health. The research concludes that raw materials for biofuel production can be readily cultivated in Nigeria, particularly in the South-East and South-South and its usage will compliment the use of fossil energy and greatly reduced environmental impact of fossil fuel.
Gas Chromatographic Determination of Glycerol and Triglycerides in Biodiesel from Jatropha and Castor Vegetable Oils
Authors: Okullo A. , Ogwok P. , Temu A.K. , Ntalikwa J.W.
Published: September 2013

Monoacylglycerols and diacylglycerols are intermediate compounds in biodiesel which result from incomplete transesterification reaction during biodiesel production. Traces of free glycerine and partially reacted triacylglycerols are also found in biodiesel. These contaminants cause serious operational problems in engines, such as engine deposits, filter plugging, and emissions of hazardous gasses. Increased levels of these contaminants in biodiesel compromise quality which is vital for commercialisation of this product. In this work, levels of free glycerine and total glycerine in jatropha methyl ester (JME) and castor methyl ester (CME) were determined using gas chromatography (GC) equipment. Amounts of free and total glycerine in JME and CME were generally high compared to the ASTM D6751 and EN14214 recommended values. Free glycerine from JME was 0.1% wt compared to 0.02% wt (ASTM D6751) and 0.01% wt (EN14214) values whereas the total glycerine from JME was 2.96% wt compared to 0.24 %wt (ASTM D6751) and 0.21% wt (EN14214). These discrepancies could have resulted from insufficient purification of the product and incomplete conversion or due to the high temperature associated with GC analysis that might have caused pyrolysis or thermal degradation of certain lipid components. Castor methyl ester free glycerine was 0.14% wt while total glycerine was 13.21% wt. This can still be explained by the same reasons given for JME. Thermal decomposition of lipid components in a GC could have interfered with the summative mass closure calculations that were done to determine the total composition of the biomass.
Gravel Mining and Supply for Construction – A Case Study of Southwestern Nigeria
Authors: Dahunsi B.I.O. , Sulymon N.A.
Published: September 2013

This paper discusses the perception of gravel suppliers in the six states situated in South-western Nigeria. It reported findings from a research on gravel supply studies in the study area. Major gravel pits, together with their perceived technical characteristics in the states were identified through a structured questionnaire designed to solicit response from truck drivers and association of gravel suppliers. Based on this, factors affecting gravel supply and usage were measured by random variables devised for the purpose. The observed outcomes of the variables from the survey carried out constituted the research data. The collated data was analyzed based on quantitative method through the use of simple percentage method of data analysis. The paper posits that geological location of Lagos state is responsible for the absence of any gravel pit in the state, hence the prohibitive cost of gravel in the state when compared to other states in the zone. In all the states, more than 99% of gravel suppliers attribute transport as a major factor affecting the cost of gravels. The technical characteristics of gravels from South-western Nigeria are also perceived to be good in construction, though these assertions need to be empirically proved.
Electricity Production from Biomass in Nigeria: Options, Prospects and Challenges
Authors: Diji C.J.
Published: September 2013

Biomass power, also called bio power, is electricity produced from biomass fuels. Biomass consists of plant materials and animal products. Biomass fuels include residues from food production and processing, trees and grasses grown specifically as energy crops, and gaseous fuels produced from solid biomass and wastes. This paper highlights the various biomass materials available in the country and the available technologies that are used for converting biomass to electricity. The paper also highlights the broad policy objectives of government with regards to the development of renewable energy in general and biomass development in particular. The paper concludes by exploring based on global experiences and best practices, the various options, and their resulting prospects and challenges in producing electricity from biomass. The paper highlighting the fact that though the prospects of using biomass for electricity generation is high; land availability, plant location, scale and choice of technology and distribution of economic benefits are factors that have to be considered in deploying biomass for electricity generation in Nigeria.
Optimal Production Inventory Policies for Operations: A Case Study of PVC Pipes Production
Authors: Godwin Harold C. , Onwurah Uchendu O.
Published: September 2013

This study focuses on solving the problem of overstocking and under stocking of production inventory in manufacturing sector. To ensure effective management of inventory in manufacturing sector, three years production data were gathered and properly analyzed using multiple linear regression analysis and time series forecasting methods. A multiple linear regression model was developed in MINITAB software to make prediction for inventory requirements. From the result, the coefficient of determination (R2) is 1.00, the adjusted R2 is 1.00, F-distribution is 4.212 x 107 which is greater than any value in F-distribution table, and all these show a very strong relationship between the dependent variable and the independent variables. Also, a Time series analysis was done to make forecast of monthly inventory requirements for both raw materials and finished products. Trend analysis and Moving Average method were used in Time series forecasting, and lower Mean Absolute Percent Error (MAPE) and Mean Absolute Deviation (MAD) were used as criteria for selecting the method that gives the best forecast. From the results obtained, Trend analysis gave MAPE 13% and MAD 2350, while Moving Average gave MAPE 14% and MAD 2574. This work adds to growing body of literatures on data driven inventory management by utilizing historical data in customized software for generation of models that can effectively make forecast of inventory requirements in manufacturing sector.
Nomenclature:
a = Value of yt at t = 0; b = Trend Value; MA= Moving Average; MAD = Mean Absolute Deviation MAPE =Mean Absolute Percentage Error; N = Number of periods;
t = Period Yt = Forecast for period t y = Monthly Quantity of Product Produced α=regression constant
β1-βk=Coefficients of the independent variables
Assembly Line Re-Balancing Using Ranked Positional Weight Technique and Longest Operating Time Technique: A Comparative Analysis
Authors: Edokpia Ralph O. , Owu F.U.
Published: September 2013

Assembly line balancing is an attractive means of mass manufacturing and large-scale serial production systems. Traditionally, assembly lines are arranged in straight single-model lines and the problem is known as Simple Assembly Line balancing problem (SALBP).
In this study, two heuristic assembly line balancing techniques known as the Ranked Positional Weight Technique, and the longest operational time technique, were applied to solve the problem of single-model line balancing problem in an assembling company with the aim of comparing the efficiencies of the application of the two algorithms.
By using both methods, different restrictions were taken into consideration and two different lines balancing results were obtained. From the results obtained, Longest Operating Time Technique has higher line efficiency (85.16%) as compared to Ranked positional weight technique (79.28%) and it is easy to apply. The LOT technique gave the minimum number of workstations (27) as compared to the RPW technique (29); however the line efficiency and the number of workstation of the existing line are 74.67% and 31 respectively. This implies that the LOT technique has a better reduction in operating cost.
Geo-Spatial Information for the Location and Maintenance Management of Water Service Pipelines
Authors: Audu Henry A.P. , Ukeme U.
Published: September 2013

This study examined the geo-spatial information needed for locating and maintaining water service pipelines. Geo-spatial information about the components of water service pipelines are a sine qua non for their location above, on or under the surface of the earth as well as the effective preventive maintenance of the entire water service pipelines. The Faculty of Engineering water service network in University of Benin, Benin City, was used as a case study. The geo-spatial data of the components of water service pipelines were acquired using Global Positioning System (GPS) receivers, while the attribute data were acquired using a standard checklist. Thereafter, the geo-spatial data (GPS data) were processed, and all the GPS data acquired in geographic co-ordinates were converted to plane rectangular co-ordinates, based on Minna Datum of Nigeria, using INCA GeoMATRIX software. The rectangular coordinates were exported into Autodesk Land development software, and vector model of the water service infrastructure in digital format was produced. A database was designed and created for geo-spatial and attribute information of various components of water service infrastructure (WSI). The study has revealed the locations of the burst pipes and the control valves that were malfunctioning, where the water pumped from the ground level storage reservoir, ooze out and caused artificial water scarcity in the Faculty of Engineering. The burst pipes were replaced with Unplasticised Polyvinyl Chloride (uPVC) pipes since they are nowadays most preferred for water supply piping. The control valves were also replaced with new ones. The GPS coordinates obtained in this study were used to determine the locations of the various components of water service infrastructure (WSI) in the study area. The geo-spatial and attribute information of hydraulic characteristics of the WSI has facilitated the planning, updating, operation and maintenance management of water service scheme in the study area. Furthermore, the study has provided a dynamic water service scheme of the Faculty of Engineering in digital format, which supersedes the existing, static water service scheme that is difficult to update, maintain and in analogue format. The dynamic water service scheme as well as the geo-spatial information of WSI can be updated and maintained regularly.
An Assessment of the Ambient Air Quality around Major Road Intersections within Warri Metropolis
Authors: Ogunnowo S.A. , Igbafe A.I.
Published: September 2013

An evaluation of the ambient air quality of emitted gases and particles at major road junctions within Warri conurbation was carried out. The study was aimed at ascertaining if air pollution levels exceeded the acceptable limits during weekdays as well as attempt to target the root causes. Ambient air was monitored from strategic locations at eight major road junctions sparsely distributed within residential areas for in-situ measurement of NO2, SO2, CO and PM10 concentrations. Monitoring was done consecutively for a period of two weeks at four single-carriage and four dual-carriage roads to test the contributions of traffic on air quality. The averages of the minimum and the maximum daily observations over the entire sampling period ranged between 0.02452ppm and 0.05684ppm for NO2, while that of SO2 ranged between 0.00564ppm and 0.05654ppm, and that of CO ranged between 0.438ppm and 4.890ppm, whereas PM10 yielded 13.602μg/m3 as minimum and 122.124μg/m3 as maximum levels. As was expected, concentrations from all the single carriage roads were higher than those from the dual carriage roads owing to the heavy traffic congestions in single-lane roads. This study also revealed that only the NO2 values obtained around Robinson plaza and Warri main market junctions were perilously close to the specified FMENV levels for hourly exposure. This being that there were rapid oxidation of NO to NO2 from vehicular emissions. However, the presence of high levels of NO2 is synonymous to high ground level ozone production environment, consequently, a high oxidation region of free radicals which could lead to more particulate matter formation during advection.
Gully Morphology and Gully Erosion Control in Calabar, Cross River State, Nigeria
Authors: Ehiorobo J.O. , Ogirigbo O.R.
Published: September 2013

Gully erosion is a highly visible form of soil erosion that results in large volume of soil and sediment transport. Gully processes have a three dimensional nature that are affected by a wide array of factors and processes which include topography, soils, land use and climatic events. In this study the four major Gully erosion sites in Calabar including Ikot Efangha Mkpa, Bebobsco, Inyang Ansa (Atimbo) and Winners, present case studies scenarios. Morphological parameters of the gullies including length, width, depth, slope, area e.t.c were determined from GPS and Total Station Surveys. Meteorological data were obtained from meteorological station in Calabar while soil characteristics for the study areas were obtained from soil samples collected from the site and analysed in the laboratory. The effects of these on the rate of soil loss and gullying were determined.Using hydrological, hydraulics and structural analysis along with the acquired data, control measures were proposed for the gully sites. These included the design of drop structures to control the runoff from the gully heads and prevent further under cutting of the heads. The use of Vertiver grass for bank stabilization and catchment areas protection was proposed. The results of the studies and control measures proposed can be adopted for planning for gully remediation and control in other similar situations.
Comparative Evaluation of Dolerite and Syenite as Crushed Stone Aggregate
Authors: Eze E.O. , Orie O.U.
Published: September 2013

Dolerite and syenite were comparatively studied and evaluated for their potential as crushed stone for civil engineering construction. Properties of the rocks tested included specific gravity, moisture absorption, Schmidt hammer rebound, point-load strength, unconfined compressive strength, Los Angeles abrasion, aggregate crushing value, sodium sulphate soundness, and ultrasound velocity. The thermal heat capacity and coefficient of expansion of the stones were also determined. The rocks had high specific gravity of over 2.75, high compressive strength of 196-256 MPa, high point load index (Is50) of 17-23 MPa and low porosity of 0.27-0.29 % required of good aggregates. However, the rather high moisture absorption and high magnesium sulphate loss of the rocks exceeded the 3 and 18 % considered as the upper limits for good aggregates. This raised concern as to the durability of the rocks under aggressive environment. Also, the ferromagnesian minerals of the dolerite are prone to deteriorate badly under harsh environment. The typically elongate and angular aggregate shape of dolerite aggregate meant poor mix workability and more cement requirement for a given strength than the less angular syenite aggregate.
Study of Swift Heavy Ion Irradiation Induced Nanophases of TiO2
Authors: Thakurdesai Madhavi , Mahadkar A. , Bhattacharyya Varsha
Published: September 2013

Ion beam irradiation is a unique non-equilibrium technique for phase formation and material modification. Localized rise in temperature and ultra fast (~1012 s) dissipations of impinging energy make it an attractive tool for nanostructure synthesize. Dense electronic excitation induced spatial and temporal confinement of high energy in a narrow dimension leads the system to a highly non-equilibrium state and the system then relaxes dynamically inducing nucleation of nanocrystals along the latent track. In the present investigation, amorphous thin films of TiO2 are irradiated by 100 MeV Ag ion beam. These irradiated thin films are characterized by Atomic Force Microscopy (AFM), Glancing Angle X-ray Diffraction (GAXRD), Transmission Electron Microscopy (TEM) and UV-VIS absorption spectroscopy. AFM and TEM studies indicate formation of circular nanoparticles of size 10±2 nm in a film irradiated at a fluence of 1×1012 ions.cm-2. Nanophase formation is also inferred from the blueshift observed in UV-VIS absorption band edge.
Stress Measurement of an Austenitic Stainless Steel Foil by cos2χ Method Using Polychromatic Laboratory X-Rays
Authors: Akiniwa Yoshiaki , Hiramura Taro
Published: September 2013

Elastic-plastic deformation properties of austenitic stainless steel foils were evaluated by using polychromatic laboratory X-rays. The transmitted optical system was used for stress measurement. The diffraction elastic constants for several diffraction planes were measured under monotonic loading by the cos2χ method. The diffraction energy decreased almost linearly with increasing cos2χ, and the slope of the cos2χ diagram decreased with increasing applied stress. Measured diffraction elastic constants were compared with the theoretical values calculated by the Kröner model. The experimental value agreed well with the theoretical value. The lattice strain measured during plastic deformation depended on the diffraction plane. The full width at half maximum increased with applied plastic strain. From the the diffraction-plane dependence of the lattice strain, the full width at half maximum and the diffraction intensity can be evaluated using polychromatic laboratory X-rays.
Birefrengent Residual Stress and Improved Injection Mold Design
Authors: Hanan Jay C.
Published: September 2013

Efficient manufacturing requires consistency. Automated equipment is designed to accept a small range of input variability and quickly sort and process for next steps. A case study for injection molding of polyethylene terephthalate preforms for use in stretch-blow molding was presented. One convenient method for measuring stresses in optically transparent birefringent parts is photoelasticity. Using cross-polarized light, fringes proportional to the stress state were observed. Faster cooling improved the residual stress state in the injected preforms. The improvements were both in magnitude, as represented by the frequency of fringes and consistency, as represented by the improved symmetry of the fringes. Lower pressure in the mold also aided in improving the residual stress state. Reducing the pressure needed to inject was accomplished by increasing the vent width.
Cementite Dissolution in Cold Drawn Pearlitic Steel Wires: Role of Dislocations
Authors: Chakraborty Jay , Maity Tias , Ghosh Mainak , Das Goutam , Chandra Sanjay
Published: September 2013

Despite numerous investigations in the past, mechanism of cementite dissolution has still remained a matter of debate. The present work investigates cementite dissolution during cold wire drawing of pearlitic steel (~ 0.8wt% carbon) at medium drawing strain (up to true strain 1.4) and the role of dislocations in the ferrite matrix on the dissolution process. Quantitative phase analysis using x-ray diffraction (XRD) confirms more than 50% dissolution of cementite phase at drawing strain ~ 1.4. Detail analysis of the broadening of ferrite diffraction lines confirms presence of strain anisotropy in ferrite due to high density of dislocations (~ 1015m-2) at drawing strain 1.4. The results of the analysis shows that the screw dislocations near the ferrite-cementite interface are predominantly responsible for pulling the carbon atoms out of the cementite phase leading to its dissolution.
Distribution of Residual Stresses in 1070 Single Phase Aluminium with Grain Size Gradient Formed by RBT Treatment
Authors: Enomoto Y. , Nishimura T. , Sato H. , Tanaka S.I.
Published: September 2013

Control of microstructure in single phase alloys are relatively limited and less way of expedient are available compared to multiphase alloys. Authors have attempted microstructural control of single phase alloy by formation of distribution of plastic strain and residual stresses. In this paper, residual stress distribution of 1070 single phase aluminium with RBT (Rotary Bending and Tensile) loading have been measured by 2D-XRD method. After suitable heat treatment, the alloy show spatial grain size distribution of 30-150μm. Measured stress tensor enabled by 2D-XRD method clealy show distribution of stress components of residual stress tensors and principal stresses. Direction of the principal stresses gradually rotate depending on position from center to radial direction. Even after annealing, the direction of principal axis agree with that of torsion during the RBT treatment. This results show possibility of control of microstructure in single phase material accomplished by introduction of gradual distribution of residual stresses.
Comparison of Internal and Residual Stresses Measured by Strain-Dip Test and XRD during High Temperature Deformation of Al-Mg Solid Solutions
Authors: Sato H. , Enomoto Y. , Omote K. , Tanaka S.I.
Published: September 2013

Creep behavior of solid solution alloys are reasonably explained by concepts of the “internal and effective stress of high temperature deformation”. The internal stress is considered to be brought by formation of dislocation substructures, and the dislocation structures should have caused long range stress filed in interior of materials. Thus, residual stresses should also be brought by the same origin. In this paper, measurements of the residual stresses after creep deformation by 2D-Xray method are attempt, and the stresses are compared with so-called the “internal stress of high temperature deformation” measured by strain-dip stress-transient test. Although, the stress tensor depends on the deformation condition, the relation with the applied stress show complex manner at a glance. The maximum principal stresses, however, show relatively smaller than the applied stress, and fairly agree with that measured by strain-dip stress-transient technique. Importance of further considerations of the origin of so-called internal stresses is suggested.
Residual Stresses in the Hot Sprues of as-cast Mg-Zn Alloys Investigated by STRESS-SPEC Neutron Diffractometer
Authors: Gan Wei Min , Huang Yuan Ding , Wang Zhi , Hort Norbert , Hofmann Michael
Published: September 2013

Residual strains near the sprues of ingots with different contents of Zn (6 wt. % and 9 wt. %) were measured using neutron diffraction. The results showed that the increase of Zn content decreases the residual stress in the hot sprue region. These results are good in agreement with that obtained by the measurement of hot tearing susceptibility.
Characteristics of Residual Stress by Water-Jet Peening
Authors: Suzuki Kenji , Shobu Takahisa , Shiro Ayumi
Published: September 2013

The specimen material was austenitic stainless steel, SUS316L. The residual stress was induced by water-jet peening. The residual stress was measured using the 311 diffraction with conventional X-rays. The measured residual stress showed the equi-biaxial stress state. To investigate thermal stability of the residual stress, the specimen was aged thermally at 773 K in air to 1000 h. The residual stress kept the equi-biaxial stress state against the thermal aging. Lattice plane dependency of the residual stress induced by water-jet peening was evaluated using hard synchrotron X-rays. The residual stress measured by the soft lattice plane showed the equi-biaxial stress state, but the residual stress measured by the hard lattice plane did not. In addition, the distributions of the residual stress in the depth direction were measured using a strain scanning method with hard synchrotron X-rays and neutrons.
In Situ Measurement of Thermal Strain during Fusion Welding
Authors: Reisgen Uwe , Geffers Christoph , Sharma Rahul , von der Heydt Jana
Published: September 2013

Temperature-induced strain with, at the same time, reduced formability is, among other things, responsible for crack development in the range of high temperatures. For a more detailed examination of these so-called hot cracks, experimental measurements of the strain during the welding process have been carried out using neutron diffraction. The measurement of strain is important since it exerts decisive influence on the development of cracks.
Finite Element Analysis of the Rolling-Sliding Contact of Vibrationally Loaded Bearings Based on a Micro Friction Model
Authors: Konrad Andreas , Nierlich Wolfgang , Gegner Jürgen
Published: September 2013

Mixed friction acting in a rolling contact increases the v. Mises equivalent stress and shifts the maximum towards the surface. Tangential stresses are superimposed to the stress distribution. The resulting position of the maximum v. Mises stress depends on the magnitude of the friction coefficient and is located directly on the surface from values of about 0.25 upwards. The impact of three-dimensional machine vibrations on rolling bearings in operation can cause severe mixed friction running conditions. Residual stress distributions measured on indentation-free raceways indicate high friction coefficients of up to greater than 0.25. The surfaces reveal smoothing of the finishing structure but no adhesive wear. The simulation of the vibrationally loaded rolling-sliding contact is based on the tribological model of localized friction coefficient. This approach avoids seizing by allowing for increased friction only in intermittently changing subareas of the contact at low sliding speed. The macroscopic friction coefficient, meeting a mixing rule, does not exceed 0.1. The finite element method (FEM) is used for the stress analysis. In the first step, a simplified FEM model involves a circumferentially oriented band of high friction coefficient from 0.2 to 0.5 within a cylindrical roller contact. The resulting depth distributions of the v. Mises equivalent stress during overrolling and the corresponding residual stresses are evaluated below the inner ring raceway of the bearing. The features of the FEM model are discussed in detail. The increased sliding friction in the band shifts the maximum of the v. Mises equivalent stress to the surface. Compressive residual stresses are induced in the edge zone. Depending on the applied Hertzian pressure, an additional subsurface peak occurs. First results of the finite element analysis are presented.
Depth-Resolved Residual Stress Analysis with High-Energy Synchrotron X-Rays Using a Conical Slit Cell
Authors: Staron Peter , Fischer Torben , Keckes Jozef , Schratter Sonja , Hatzenbichler Thomas , Schell Norbert , Müller Martin , Schreyer Andreas
Published: September 2013

A conical slit cell for depth-resolved diffraction of high-energy X-rays was used for residual stress analysis at the high-energy materials science synchrotron beamline HEMS at PETRA III. With a conical slit width of 20 µm and beam cross-sections of 50 µm, a spatial resolution in beam direction of 0.8 mm was achieved. The setup was used for residual stress analysis in a drawn steel wire with 8.3 mm diameter. The residual stress results were in very good agreement with results of a FE simulation.
A compilation of radiocarbon dates relating to the age of sensitive clay landslides in the Ottawa Valley, Ontario-Québec
Authors: Brooks G R , Medioli B E , Aylsworth J M , Lawrence D
E
Published: September 2013

This Open File contains a compilation of 122 published and unpublished radiocarbon dates relating to the age of 39 sensitive clay landslides and three "disturbed terrain" features in the Ottawa Valley, southeastern Ontario/southwestern Québec. Sixteen tables
contain either the date(s) for individual landslides (or disturbed terrain) or the date(s) for multiple landslides within a specific geographical area. A brief paragraph introduces each table and overviews the landslide or disturbed terrain and the associated radiocarbon date(s). Each table lists
the attributes of the dates, including sampling location, dated material, dating results, and contextual information between the age and the landslide/disturbed terrain. It is intended that this dataset will aid future studies investigating the chronology of prehistoric sensitive clay landslides in
the Ottawa Valley and St. Lawrence Lowlands region.
Genetic testing of canine degenerative myelopathy in the South African Boxer dog population
Authors: Zeiler Gareth E. , Van der Zwan Henriette , Oosthuizen Marinda C.
Published: September 2013

Canine degenerative myelopathy (DM) is a progressive disease process that is diagnosed late in life and mainly affects the pelvic limbs. Factors that make an ante-mortem definitive diagnosis of DM include: an insidious onset and clinical manifestation that mimics other disease processes of the pelvic limbs (hip dysplasia, cranial cruciate ligament rupture, etc.) or there may even be concurrent disease processes, old-age onset and lack of reliable diagnostic methods. Until recently, South African dog owners had to submit samples to laboratories overseas for genetic testing in order to confirm an affected dog (homozygous A/A) and to aid in the ante-mortem diagnosis of DM. Only affected dogs have been confirmed to manifest the clinical signs of DM. This study aimed to verify whether genetic testing by a local genetic laboratory was possible in order to detect a missense mutation of the superoxide dismutase gene (SOD1) that is implicated in causing the clinical signs of DM. The study also aimed to detect and map the inheritance of this disease process in a local Boxer dog population where the pedigree of the sampled population was known. Venous blood collected from Boxer dogs using a simple random sampling technique. The samples were genotyped for the SOD1:c.118GA polymorphism. Carrier and affected Boxer dogs were detected. A pedigree that demonstrated the significance of inheriting a carrier or affected state in the population was mapped. The present study concludes that genotyping of the missense mutation in Boxer dogs is possible in South Africa. There are carrier and affected Boxer dogs in the local population, making DM a plausible diagnosis in aged dogs presenting with pelvic limb pathology.
Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions (RECONCILE): activities and results
Authors: von Hobe M. , Bekki S. , Borrmann S. , Cairo F. , D'Amato F. , Di Donfrancesco G. , Dörnbrack A. , Ebersoldt A. , Ebert M. , Emde C. , Engel I. , Ern M. , Frey W. , Genco S. , Griessbach S. , Grooß J.-U. , Gulde T. , Günther G. , Hösen E. , Hoffmann L. , Homonnai V. , Hoyle C. R. , Isaksen I. S. A. , Jackson D. R. , Jánosi I. M. , Jones R. L. , Kandler K. , Kalicinsky C. , Keil A. , Khaykin S. M. , Khosrawi F. , Kivi R. , Kuttippurath J. , Laube J. C. , Lefèvre F. , Lehmann R. , Ludmann S. , Luo B. P. , Marchand M. , Meyer J. , Mitev V. , Molleker S. , Müller R. , Oelhaf H. , Olschewski F. , Orsolini Y. , Peter T. , Pfeilsticker K. , Piesch C. , Pitts M. C. , Poole L. R. , Pope F. D. , Ravegnani F. , Rex M. , Riese M. , Röckmann T. , Rognerud B. , Roiger A. , Rolf C. , Santee M. L. , Scheibe M. , Schiller C. , Schlager H. , Siciliani de Cumis M. , Sitnikov N. , Søvde O. A. , Spang R. , Spelten N. , Stordal F. , Sumińska-Ebersoldt O. , Ulanovski A. , Ungermann J. , Viciani S. , Volk C. M. , vom Scheidt M. , von der Gathen P. , Walker K. , Wegner T. , Weigel R. , Weinbruch S. , Wetzel G. , Wienhold F. G. , Wohltmann I. , Woiwode W. , Young I. A. K. , Yushkov V. , Zobrist B. , Stroh F.
Published: September 2013

Abstract. The international research project RECONCILE has addressed central questions regarding polar ozone depletion, with the objective to quantify some of the most relevant yet still uncertain physical and chemical processes and thereby improve prognostic modelling capabilities to realistically predict the response of the ozone layer to climate change. This overview paper outlines the scope and the general approach of RECONCILE, and it provides a summary of observations and modelling in 2010 and 2011 that have generated an in many respects unprecedented dataset to study processes in the Arctic winter stratosphere. Principally, it summarises important outcomes of RECONCILE including (i) better constraints and enhanced consistency on the set of parameters governing catalytic ozone destruction cycles, (ii) a better understanding of the role of cold binary aerosols in heterogeneous chlorine activation, (iii) an improved scheme of polar stratospheric cloud (PSC) processes that includes heterogeneous nucleation of nitric acid trihydrate (NAT) and ice on non-volatile background aerosol leading to better model parameterisations with respect to denitrification, and (iv) long transient simulations with a chemistry-climate model (CCM) updated based on the results of RECONCILE that better reproduce past ozone trends in Antarctica and are deemed to produce more reliable predictions of future ozone trends. The process studies and the global simulations conducted in RECONCILE show that in the Arctic, ozone depletion uncertainties in the chemical and microphysical processes are now clearly smaller than the sensitivity to dynamic variability.
Mean winds in the MLT, the SQBO and MSAO over Ascension Island (8° S, 14° W)
Authors: Day K. A. , Mitchell N. J.
Published: September 2013

Abstract. Mean winds in the mesosphere and lower thermosphere (MLT) over Ascension Island (8° S, 14° W) have been measured at heights of approximately 80–100 km by a meteor radar. The results presented in this study are from the interval October 2001 to December 2011. In all years, the monthly-mean meridional winds display a clear annual oscillation. Typically, these winds are found to be southward during April–October, when they reach velocities of up to about −23 m s−1, and northward throughout the rest of the year, when they reach velocities up to about 16 m s−1. The monthly-mean zonal winds are generally westward throughout most of the year and reach velocities of up to about −46 m s−1. However, eastward winds are observed in May–August and again in December at the lower heights observed. These eastward winds reach a maximum at heights of about 86 km with velocities of up to about 36 m s−1, but decay quickly at heights above and below that level. The mesospheric semi-annual oscillation (MSAO) is clearly apparent in the observed monthly-mean zonal winds. The winds in first westward phase of the MSAO are observed to be much stronger than in the second phase. The westward phase of the MSAO is found to maximise at heights of about 84 km with typical first-phase wind velocities reaching about −35 m s−1. These meteor-radar observations have been compared to the HWM-07 empirical model. The observed meridional winds are found to be generally more southward than those of the model during May–August, when at the lower heights observed the model suggests there will be only weakly southward, or even northward, winds. The zonal monthly-mean winds are in generally good agreement, although in the model they are somewhat less westward than those observed. Throughout the observations there were eight occasions in which the first westward phase of the MSAO was observed. Strikingly, in 2002 there was an event in which the westward winds during the first phase of the MSAO were much stronger than normal and reached velocities of about −75 m s−1. This event is explained in terms of a previously proposed mechanism in which the relative phasing of the stratospheric quasi-biennial oscillation (SQBO) and the MSAO allows an unusually large flux of gravity waves of large westward phase speed to reach the mesosphere. It is the dissipation of these gravity waves that then drives the MLT winds to the large westward velocities observed. It is demonstrated that the necessary SQBO–MSAO phase relationship did indeed exist during 2002, but not during the other years observed here. This demonstration provides strong support for the suggestion that extreme zonal-wind events during the MSAO result from the modulation of gravity-wave fluxes.
Aerosol airmass type mapping over the Urban Mexico City region from space-based multi-angle imaging
Authors: Patadia F. , Kahn R. A. , Limbacher J. A. , Burton S. P. , Ferrare R. A. , Hostetler C. A. , Hair J. W.
Published: September 2013

Abstract. Using Multi-angle Imaging SpectroRadiometer (MISR) and sub-orbital measurements from the 2006 INTEX-B/MILAGRO field campaign, in this study we explore MISR's ability to map different aerosol air mass types over the Mexico City metropolitan area. The aerosol air mass distinctions are based on shape, size and single scattering albedo retrievals from the MISR Research Aerosol Retrieval algorithm. In this region, the research algorithm identifies dust-dominated aerosol mixtures based on non-spherical particle shape, whereas spherical biomass burning and urban pollution particles are distinguished by particle size. Two distinct aerosol air mass types based on retrieved particle microphysical properties, and four spatially distributed aerosol air masses, are identified in the MISR data on 6 March 2006. The aerosol air mass type identification results are supported by coincident, airborne high-spectral-resolution lidar (HSRL) measurements. Aerosol optical depth (AOD) gradients are also consistent between the MISR and sub-orbital measurements, but particles having single-scattering albedo of ≈0.7 at 558 nm must be included in the retrieval algorithm to produce good absolute AOD comparisons over pollution-dominated aerosol air masses. The MISR standard V22 AOD product, at 17.6 km resolution, captures the observed AOD gradients qualitatively, but retrievals at this coarse spatial scale and with limited spherical absorbing particle options underestimate AOD and do not retrieve particle properties adequately over this complex urban region. However, we demonstrate how AOD and aerosol type mapping can be accomplished with MISR data over complex urban regions, provided the retrieval is performed at sufficiently high spatial resolution, and with a rich enough set of aerosol components and mixtures.
The diurnal and semidiurnal tides over Ascension Island (° S, 14° W) and their interaction with the stratospheric quasi-biennial oscillation: studies with meteor radar, eCMAM and WACCM
Authors: Davis R. N. , Du J. , Smith A. K. , Ward W. E. , Mitchell N. J.
Published: September 2013

Abstract. Horizontal winds in the mesosphere have been measured over Ascension Island (8° S, 14° W) in the tropical mid-Atlantic region throughout the years 2002–2011. The observations were made by a very high frequency (VHF) meteor radar. The observations reveal the presence of atmospheric tides of large amplitude. The observations are analysed to characterise the seasonal and interannual variability of the diurnal and semidiurnal tides. Monthly-mean diurnal tidal amplitudes are found to reach values as large as 48 m s−1 in the meridional component and 41 m s−1 in the zonal. A semiannual seasonal variation is found in diurnal tidal amplitudes with amplitude maxima at the equinoxes and amplitude minima at the solstices. Diurnal tidal meridional vertical wavelengths are generally in the range 24–30 km. The diurnal zonal vertical wavelengths are similar to the meridional, except for the winter months when the zonal vertical wavelengths are much longer, occasionally exceeding 100 km. Semidiurnal amplitudes are observed to be significantly smaller than diurnal amplitudes. Semidiurnal vertical wavelengths range from 20 to more than 100 km. Our observations of tidal amplitudes and phases are compared with the predictions of the extended Canadian Middle Atmosphere Model (eCMAM) and the Whole Atmosphere Community Climate Model (WACCM). Both eCMAM and WACCM reproduce the trend for greater diurnal amplitudes in the meridional component than the zonal. However, eCMAM tends to overestimate meridional amplitudes, while WACCM underestimates both zonal and meridional amplitudes. Vertical wavelength predictions are generally good for both models; however, eCMAM predicts shorter diurnal zonal vertical wavelengths than are observed in winter, while WACCM predicts longer zonal vertical wavelengths than observed for the semidiurnal tide for most months. Semidiurnal amplitude predictions are generally good for both models. It is found that larger-than-average diurnal and semidiurnal tidal amplitudes occur when the stratospheric quasi-biennial oscillation (QBO) at 10 hPa is eastwards, and smaller-than-average amplitudes occur when it is westwards. Correlations between the amplitude perturbations and the El Niño Southern Oscillation are also found. The precise mechanism for these correlations remains unclear.
Heterogeneous formation of polar stratospheric clouds – Part 1: Nucleation of nitric acid trihydrate (NAT)
Authors: Hoyle C. R. , Engel I. , Luo B. P. , Pitts M. C. , Poole L. R. , Grooß J.-U. , Peter T.
Published: September 2013

Abstract. Satellite-based observations during the Arctic winter of 2009/2010 provide firm evidence that, in contrast to the current understanding, the nucleation of nitric acid trihydrate (NAT) in the polar stratosphere does not only occur on preexisting ice particles. In order to explain the NAT clouds observed over the Arctic in mid-December 2009, a heterogeneous nucleation mechanism is required, occurring via immersion freezing on the surface of solid particles, likely of meteoritic origin. For the first time, a detailed microphysical modelling of this NAT formation pathway has been carried out. Heterogeneous NAT formation was calculated along more than sixty thousand trajectories, ending at Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) observation points. Comparing the optical properties of the modelled NAT with these observations enabled a thorough validation of a newly developed NAT nucleation parameterisation, which has been built into the Zurich Optical and Microphysical box Model (ZOMM). The parameterisation is based on active site theory, is simple to implement in models and provides substantial advantages over previous approaches which involved a constant rate of NAT nucleation in a given volume of air. It is shown that the new method is capable of reproducing observed polar stratospheric clouds (PSCs) very well, despite the varied conditions experienced by air parcels travelling along the different trajectories. In a companion paper, ZOMM is applied to a later period of the winter, when ice PSCs are also present, and it is shown that the observed PSCs are also represented extremely well under these conditions.