dalhousie university - 2014 peas graduate symposium book ......the aqueous corrosion response of tic...

2014

GRADUATE RESEARCH SYMPOSIUM

PROGRAM

Sustainable Engineering Research

DEPARTMENT OF PROCESS ENGINEERING & APPLIED SCIENCE

DALHOUSIE UNIVERSITY

HALIFAX, NOVA SCOTIA

Dr. Mark Gibson

Graduate Programs Coordinator

Paula McKenna

Graduate Secretary

William Judge

MASc Materials Engineering

May 5, 2014

DEPARTMENT OF PROCESS ENGINEERING AND APPLIED SCIENCE

GRADUATE PROGRAMS

Biological Engineering

Chemical Engineering

Food Science and Technology

Materials Engineering

PROGRAM

Monday May 5, 2014

8:00 am Registration & Poster Mounting (Sexton Gym) Ms. Paula McKenna, Secretary

Department of Process Engineering and Applied Science.

8:45 am Introduction and Welcome (B308)

Chair – Dr. Mark Gibson, Graduate Coordinator

Department of Process Engineering and Applied Science

Dr. Josh Leon (Dean of Engineering)

9:00 am Poster Slide Presentations (B227 and B308)

Chair – Will Judge

10:30am Coffee (B308)

11:00 am Air Pollutant Emissions Associated with the Oil Sands: Uncovering

the Impacts

Jeff Brook, Environment Canada (B308)

12:00 pm Lunch and Poster Judging (Sexton Gym). Lunch is provided by

the Department. Poster presenters will be next to their poster for

judging during the lunch break.

1:00 pm Fermenting is for more than just beer! New technologies for

fermenting algae to produce renewable oils

Roberto Armenta, Mara Renewables Corporation (B308)

2:00 pm Oral Presentations (B227, B308 and D415)

4:00 pm Award Presentation and closing remarks (Sexton Gym)

Chair – Dr. Mark Gibson, Graduate Coordinator

Department of Process Engineering and Applied Science

KEYNOTE SPEAKERS

Dr. Jeff Brook is a senior scientist at Environment Canada and an Assistant

Professor in the Dalla Lana School of Public Health and Department of Chemical

Engineering at the University of Toronto.

Dr. Brook leads Environment Canada’s mobile lab activities and several projects

involving lab, field and modeling activities studying urban and regional air quality,

emphasizing fine particulate matter, interactions with meteorology and exposure

assessment related to a range of health studies.

Dr. Brook currently co-leads a Canadian Network of Centres of Excellence

(AllerGen) program on Genes and Environment and leads the environmental

exposure assessment component of a national birth cohort, known as CHILD,

examining the influences of environmental factors on children's health.

Roberto E. Armenta,

Mara Renewables Corporation,

Canada

Dr. Armenta is Chief Scientist –

Director of R&D at Mara Renewables

Corporation in Canada

Roberto leads the most advanced R&D program to produce heterotrophic

microalgae oil in Canada, including work on genetics, fermentation optimization

and downstream processing. His research focuses on critical issues, including yield

coefficients, strain development, process scale-up, contamination control, and oil

extraction. He was recognized as the top Ph.D. student in Biological Sciences by

his university.

Roberto conducted worldwide graduate research: Loughborough University in

England, University of Concepcion in Chile, Superior Institute of Technology in

Portugal and National Research Council of Canada. Roberto has extensive

experience in biological processes to produce both microbial high-value products

and commodities, including carotenoids, nutritional oils and biofuels.

Roberto directed the R&D at Ocean Nutrition Canada to produce nutritional lipids

from microalgae. He received his B.Eng. in Biotechnological Engineering from the

Technological Institute of Sonora, M.Sc. in Biotechnology and Ph.D. in Biological

Sciences from the Autonomous Metropolitan University, Mexico

2014 Poster Presentations:

Development of a Microbubble-Aerated High Performance Airlift Bioreactor

Albahlool Omar Idhbeaa, PhD Chemical Engineering

Evaluation of Nova Scotia Agricultural Resources Available for Biomass Production and

Utilization

Allan Thomson, PhD Biological Engineering

Use of Novel, Natural Antimicrobial Compounds for the Removal of Mixed Biofilms formed

by Listeria Monocytogenes and Commensal Bacteria

Celine d’Entremont, MSc Food Science and Technology

Suitability of Scaling Laws for Extrapolating Closed-Volume Dust Explosion Parameters to

Industry Scale and Process Applications

Chris Cloney, PhD Chemical Engineering

Textural Softening of Arctic Surf Clams (Mactromeris Polymyna)

David Bent, MSc Food Science and Technology

Characterization of Waste Asphalt Shingles as a Fuel for Co-combustion with Coal in Cement

Kilns

Ebenezer Asamany, PhD Chemical Engineering

Optimization of Ultrasound-Assisted Extraction and Encapsulation of Phenolic-Rich Extract

from Haskap Berries (Lonicera Caerulea L.)

Giovana B Celli, PhD Biological Engineering

Spark Plasma Sintering of Atomized Aluminum Powders

Gregory A.W. Sweet, MASc Materials Engineering

Single Phase Composition in the Li-Ni-Mn-O System with Layered Structure

Jing Li, PhD Chemical Engineering

Influence of Blended Elemental and Prealloyed Aluminum Additions on the Sintering

Behaviour of Titanium Alloys

Joannie Lapointe, MASc Materials Engineering

Particle Agglomeration Effects on Explosibility and Explosive Likelihood

Josh Thistle, MASc Chemical Engineering

An Experimental Study of the Influence of Porous Media on the Rate of Hydrate Formation

Najlla Ali, MASc Chemical Engineering

Viscous Heat Generation in Nanocrystalline Suspensions

Yun Chen, MSc Food Science and Technology

2014 Oral Presentations

The Characterization of Building-Integrated Microalgae Photobioreactors

Aaron Outhwaite, MASc Biological Engineering

Characterization of Bioactive Peptides from Salmon Protein Hydrolysates

Jonathan Rolin, PhD Food Science and Technology

Source Apportionment of the Air Quality on Sable Island

Alex Hayes, MASc Biological Engineering

Effect of Microcstructure on Tribological Properties of Automotive Aluminium-Silicon Alloys

Under Low Load Condition

Avijit Sinha, MASc Materials Engineering

A Review of Bubble Drag Correlations Applicable at the Operational Conditions of the LC-

Finer™

Chris Lane, PhD Chemical Engineering

An Immersed Boundary Model for Simultaneous Heat and Mass Transfer

Devin O’Malley, MASc Chemical Engineering

Silver-Based Liquid-Liquid Extraction of EPA/DHA from Fish Oil in Minifluidic Slugflow

Reactor

Kirubanandan Shamugam, MASc Chemical Engineering

Raising Awareness of Combustible Dust Hazards

Morgan Worsford, MASc Chemical Engineering

Crack Generation in TiC-316L Steel Cermets Using Vickers Indentation

Chenxin Jin, PhD Materials Engineering

An Investigation of the Volatile Organic Compound (VOCs) Content of Beer and Formation

Pathway in Aged Beer

Priyanka Mehra, MSc Food Science and Technology

Extraction of Antioxidants from Date Palm Fruit (Phoenix Dactylifera)

Rasha Aludhaib, MASc Biological Engineering

Proton NMR Can Be Used to Measure Epoxides Derived from Lipid Oxidation

Wei Xia, MSc Food Science and Technology

Corrosion Behaviour of Alumix 123 Powder Metallurgy Aluminum Alloy

William Judge, MASc Materials Engineering

Effect of Temperature on the Wide Angle X-Ray Diffraction of Nanocrystalline Triglycerides

Xiyan Deng, MSc Food Science and Technology

Effect of Temperature Time Combinations on the Crystal Memory of Triglycerides

Yujing Wang, MSc Food Science and Technology

The Aqueous Corrosion Response of TiC and Ti(C,N) Cermets with Ni3Al-based Binders

Zhila Memarrashidi, MASc Materials Engineering

Encapsulation of Antidiabetic Salmon Protein Hydrolysates with Chitosan Coated Milk Fat

Phospholipid Lipids

Zhiyu Li, MSc Food Science and Technology

2:00 p.m. Oral Presentation – Session I (Room B227)

Introduction

2:00 p.m. The Characterization of Building-Integrated Microalgae

Photobioreactors

Aaron Outhwaite, MASc Biological Engineering

2:20 p.m. Characterization of Bioactive Peptides from Salmon Protein

Hydrolysates

Jonathan Rolin, PhD Food Science and Technology

2:40 p.m. Source Apportionment of the Air Quality on Sable Island

Alex Hayes, MASc Biological Engineering

3:00 p.m. Effect of Microcstructure on Tribological Properties of Automotive

Aluminium-Silicon Alloys Under Low Load Condition

Avijit Sinha, MASc Materials Engineering

3:20 p.m. A Review of Bubble Drag Correlations Applicable at the

Operational Conditions of the LC-Finer™

Chris Lane, PhD Chemical Engineering

2:00 p.m. Oral Presentation – Session II (Room B308)

Introduction

2:00 p.m. An Immersed Boundary Model for Simultaneous Heat and Mass

Transfer

Devin O’Malley, MASc Chemical Engineering

2:20 p.m. Silver-Based Liquid-Liquid Extraction of EPA/DHA from Fish Oil

in Minifluidic Slugflow Reactor

Kirubanandan Shamugam, MASc Chemical Engineering

2:40 p.m. Raising Awareness of Combustible Dust Hazards

Morgan Worsford, MASc Chemical Engineering

3:00 p.m. Crack Generation in TiC-316L Steel Cermets Using Vickers

Indentation

Chenxin Jin, PhD Materials Engineering

3:20 p.m. An Investigation of the Volatile Organic Compound (VOCs) Content

of Beer and Formation Pathway in Aged Beer

Priyanka Mehra, MSc Food Science and Technology

3:40 p.m. Encapsulation of Antidiabetic Salmon Protein Hydrolysates with Chitosan

Coated Milk Fat Phospholipid Lipids

Zhiyu Li, MSc Food Science and Technology

2:00 p.m. Oral Presentation – Session III (Room B415)

Introduction

2:00 p.m. Extraction of Antioxidants from Date Palm Fruit (Phoenix

Dactylifera)

Rasha Aludhaib, MASc Biological Engineering

2:20 p.m. Corrosion Behaviour of Alumix 123 Powder Metallurgy Aluminum

Alloy

William Judge, MASc Materials Engineering

2:40 p.m. Effect of Temperature on the Wide Angle X-Ray Diffraction of

Nanocrystalline Triglycerides

Xiyan Deng, MSc Food Science and Technology

3:00 p.m. Effect of Temperature Time Combinations on the Crystal Memory

of Triglycerides

Yujing Wang, MSc Food Science and Technology

3:20 p.m. The Aqueous Corrosion Response of TiC and Ti(C,N) Cermets with

Ni3Al-based Binders

Zhila Memarrashidi, MASc Materials Engineering

2014 Abstract Submissions of Biological,

Chemical, Materials Engineering and

Food Science & Technology

Graduate Students

Development of a Microbubble-Aerated High Performance Airlift Bioreactor

Albahlool Omar Idhbeaa

Dr. A. M. Al Taweel, Dr. A. Ghanem, and Dr. M. Walsh


PhD

ABSTRACT

Airlift reactors, ALR, can be considered as a variant of the well-known bubble column reactor in

which the liquid circulation flow pattern is stabilized by using a separate downcomer through

which the liquid ascending in the riser is returned to the bottom of the reactor. Airlift reactors are

therefore used extensively in many chemical, environmental, and biotechnology processes.

Additional advantages of using the ALR are their simple construction, low cost, the ability to

maintain sterile conditions, the ability to achieve high mixing rates without the presence of high

local shear rates, and the high inter-phase mass transfer rates that can be obtained in such units.

My master’s thesis investigation identified that significant improvement in the performance of

these units was achieved by using microbubbles to aerate them (Idhbeaa, 2009). This result stems

mainly from the ability of the microbubbles generated by the dual-fluid sparger (db

generate very large interfacial area of contact between the phases and efficiently circulate the liquid

within the unit. These characteristics will be used to develop a high-performance bioreactor that

can meet the demands of biologically treating high-strength wastewaters. The high oxygen transfer

rates that can be achieved will be used to overcome the major limiting steps in aerobic wastewater

treatment, while the use of biofilm inserts is expected to result in greater microbial activity and

facilitates the subsequent removal of the biomass formed.

Evaluation of Nova Scotia Agricultural Resources Available for Biomass Production and

Utilization

Allan Thomson

Dr. Kenny Corscadden


PhD

ABSTRACT

The agricultural industry, especially the greenhouse, mink and poultry industries are heavy users

of heat throughout the year. Coupled with available land resources, this places the industry in a

unique position of being able to develop and provide both the supply and the demand of biomass

based products, with the added benefit of available markets out-with the industry.

While there is a broad understanding of some of the available resources necessary in Nova Scotia

for the development of a biomass based sector, there are a large number of gaps missing before its

feasibility can be fully determined. The primary objective of this research is to collate relevant

and applicable information to make informed decisions regarding the development and future

outlook of a biomass industry and the use of biomass systems and products.

The preliminary questions raised include: what are the available and required resources for the

production of biomass crops? How can these crops be used and what final product yields can be

expected? What is the current energy practices within the agricultural industry? And, how ag-

biomass production impact upon the environment, energy consumption and agricultural producers’

bottom line?

A major component of this research aimed at answering these questions, focuses around the Life

Cycle Analysis (LCA) of viable biomass suitable for the province, identified as: Short Rotation

Coppice (SRC) Willow, Switchgrass, Reed Canary Grass and Miscanthus.

The LCA approach will look at individual case studies, focusing on current production trials, for

the production, processing and utilization of the selected biomass feedstocks. The LCA approach

will identify emissions and energy throughput and allow for comparisons to be made against the

traditional fossil fuels.

By filling in the missing ‘information gaps’, this research is intended to benefit the agricultural

and energy industries in the future development of an agricultural biomass industry.

USE OF NOVEL, NATURAL ANTIMICROBIAL COMPOUNDS FOR THE REMOVAL OF

MIXED BIOFILMS FORMED BY LISTERIA MONOCYTOGENES AND COMMENSAL

BACTERIA

Céline d’Entremont

Dr. Lisbeth Truelstrup-Hansen

MSc

ABSTRACT

Listeria monocytogenes is a Gram-positive, facultative anaerobe, opportunistic foodborne

pathogen and the cause of the worldwide recognized illness, Listeriosis. It is an indigenous

organism, living naturally in soil, water and vegetation and is transmitted to humans through

consumption of contaminated foods such as fruits, vegetables, cheeses, processed meats and

smoked seafood. Moreover, a recent study detected L. monocytogenes in more than 50% of water

samples taken from streams and lakes in two Nova Scotian communities over an 18-month period.

The main issue with Listeria is thought to be its environmental resistance and ability to form

biofilms. In food processing environments, L. monocytogenes will likely grow on food processing

surfaces with other microorganisms in mixed species biofilms. Natural alternatives such as

essential oils (EOs) are being studied for their antimicrobial and antibiofilm properties. The aim

of this research is to determine if biofilm removal regimes using natural compounds; thymol,

carvacrol, cinnamaldehyde, p-cymene, lemongrass EO, apigenin and rosmarinic acid will work

equally well on L. monocytogenes found in single and dual-species biofilms with other food-

related bacteria: Pseudomonas fluorescens, Shewanella baltica and Salmonella enterica.

These biofilms will be investigated at different development stages on different surfaces including

stainless steel (SS), to simulate the surfaces in food processing environments. The minimum

inhibitory and bactericidal concentrations (MIC, MBC) as well as the minimum biofilm inhibitory

and eradication concentrations (MBIC, MBEC) will be determined in-vitro using absorbance

readings and metabolic activity assays for single and mixed species biofilms. Biofilms will also be

grown on SS coupons and treated with each antimicrobial to determine the MBEC using a spot

plating method. The expected outcome of this research will be the development of biofilm removal

strategies that use natural biofilm inhibitors to effectively eliminate L. monocytogenes from the

food processing environments.

SUITABILITY OF SCALING LAWS FOR EXTRAPOLATING CLOSED-

VOLUME DUST EXPLOSION PARAMETERS TO INDUSTRY SCALE AND PROCESS

APPLICATIONS

Chris T. Cloney

Dr. Paul R. Amyotte & Dr. Robert C. Ripley


Doctor of Philosophy

ABSTRACT

Dust explosion hazards are a concern in any processing industry which creates, handles, transports,

or otherwise uses small particulate matter of combustible material including organics, wood,

plastic, and metals. Many of the industry standards for prevention and mitigation are formed

around prescriptive requirements based on laboratory scale closed-volume explosion testing.

Scaling of these parameters is used in determination of explosion venting requirements, application

of mitigation and suppression systems, and classification of hazardous areas.

The current Ph.D. research will investigate the influence of vessel size, vessel geometry, ignition

source, dispersion characteristics, and turbulence level on the application and accuracy of scaling

laws for closed-volume dust explosion parameters. Further review and analysis of the physical

chemistry involved during combustion of different dust classes and fundamental theory of the dust

explosion process will be completed. This will be used to determine the important length- and

time-scales, dimensionless number groups, and limiting rates involved in scaling laws for dust

explosion parameters; a thorough treatment of which is currently not found in the literature.

Numerical modelling and experimentation will be used to investigate the effect of vessel geometry,

ignition source strength, dust dispersion, and turbulence level on the application of dust explosion

scaling laws. Specific consideration will be given to hard-to-ignite dusts which have traditionally

caused significant confusion with respect to implementation of the current standard practices. This

will facilitate better extrapolation of laboratory testing results for use in the standards and

guidelines for explosion prevention and mitigation. In conjunction with increasing the scientific

knowledge an active focus of this project is on developing practical tools/theory/correlations to

supplement current scaling laws and empirical corrections.

TEXTURAL SOFTENING OF ARCTIC SURF CLAMS (MACTROMERIS

POLYMYNA)

David H. Bent

Dr. Tom A. Gill

Food Science and Technology

Master of Science

Arctic Surf Clam (Mactromeris polymyna) is a minimally processed sea food sold blanched,

shucked, frozen and consumed without further processing. The mouthfeel (texture) of surf clam

meat is predominantly dependent on the physical state of the live clam and the effects of processing

and freezing. Customer complaints have been received by a surf clam processor about textural

softening of the clam meat. The problem has been occasional but persistent forcing the processor

to search for the cause of the textural softening. Surf clams are known to contain high levels of

proteolytic cathepsin (B and D) enzymes which are a likely cause of the textural softening.

Cathepsin enzymes are normally bound within lysosomes, which are subcellular membrane bound

organelles, but can be freed and activated by trauma, stress or normal protein turnover within cells.

The purpose of this study is to determine the cause of textural softening of Arctic Surf Clam meat.

An instrumental method was developed using an Instron Model 4502 texture analyzer to

quantitatively measure textural softening of clam meat. Total cathepsin activity assays will be

performed on clam homogenates as well as free cathepsin activity assays on cytoplasmic juice

prepared by centrifugation of intact clam tissue. In this way the study will determine whether or

not there is a correlation between textural softening in surf clam meat and free active cathepsin

activity. A possible cause of increased cathepsin activity is stress caused by elevated ocean

temperatures observed by the clam processor in recent years. The effect of environmental

temperature on cathepsin activity in surf clams will be measured with live clams harvested,

acclimated and then cultivated at normal and elevated environmental temperatures (5, 10 and 20oC,

respectively).

CHARACTERIZATION OF WASTE ASPHALT SHINGLES AS A FUEL FOR CO-COMBUSTION WITH

COAL IN CEMENT KILNS

Ebenezer Asamany

Dr. Michael Pegg and Dr. Mark Gibson


PhD

ABSTRACT

The fuel and energy requirement for the production of clinker in rotary cement kilns is such that

the cement industry relies heavily on coal which does not only increase the cost of production by

virtue of its price, but also negatively affects the sustainability rating of the cement production

process because coal is a non-renewable resource. The use of cheap and readily accessible

alternative solid fuels in rotary cement kilns without adversely affecting kiln performance is of

essential interest to the industry and forms the motivation for this study. Some waste solids

destined for landfills possess large amounts of untapped energy. Redirecting such waste to a local

cement kiln presents a double edged solution to both cost and environmental concerns.

The Lafarge cement plant in Brookfield, Nova Scotia has considered practical means of using

alternative fuels including waste asphalt roofing shingles to supplement coal in the production of

clinker. The main focus of this research is to study the effects of these waste derived supplementary

fuels on the performance of rotary cement kilns. The work to be presented is a research on the use

of waste asphalt roofing shingles to supplement coal in rotary cement kilns. It covers aspects of

supplementary fuel handling; the combustion mechanism of asphalt shingles and their blends with

coal; and the analysis of emissions resulting from burning the fuel blends. Extensive field trials at

Lafarge cement plant showed that increasing the quantity of asphalt shingles used in the kiln from

the current 5-10% to about 25% is possible. Several variations in the preparation and handling of

asphalt shingles are proposed and studied to ascertain which approaches provide most room for an

increase in shingle use. The lessons learnt from the mechanisms of combustion and the challenges

encountered while engineering an increased use of asphalt shingles as a supplementary fuel will

add to existing knowledge in waste-to-energy processes in industry.

OPTIMIZATION OF ULTRASOUND-ASSISTED EXTRACTION AND

ENCAPSULATION OF PHENOLIC-RICH EXTRACT FROM HASKAP BERRIES

(LONICERA CAERULEA L.)

Giovana B Celli

Dr. Amyl Ghanem and Dr. Su-Ling Brooks

PhD Program in Biological Engineering

ABSTRACT

Haskap berries (Lonicera caerulea L.) are a recent arrival to the North American market and are

also known as blue honeysuckle or honeyberries. Haskap berries have higher ascorbic acid and

anthocyanin content in comparison to other berries known for their health-promoting benefits,

such as blueberries. Due to the perishable nature of fresh haskap berries, value-added products are

necessary to enable the commercial viability of the haskap berry industry. The extraction of

bioactive compounds from haskap berries is critical for the development of value-added products,

such as nutraceuticals and functional food ingredients, and can be influenced by several

experimental factors. Although researchers have used ultrasound-assisted extraction to obtain

phytochemicals from haskap berries, no optimization has been done. Therefore, the objective of

this study is to optimize ultrasound-assisted extraction of phenolic and anthocyanins from freeze-

dried haskap berries. Plackett-Burman design will be used to screen for the most relevant factors

and main effects on the extraction, namely solid-to-liquid ratio, solvent concentration, acid

concentration, ultrasound bath temperature and extraction time. Total phenolic and anthocyanin

content will be evaluated by Folin-Ciocalteu assay and pH differential method, respectively.

Preliminary results indicated that the overall anthocyanin content of the extracts ranged from 3.9

to 20.7 mg cyanidin 3-glucoside equivalents per g of dried weight. Optimization will be based on

response surface methodology (RSM), using Box-Behnken (BB) design. Later steps will include

the preparation of nanoparticles from the optimized extract as a delivery system, including stability

and release studies.

SPARK PLASMA SINTERING OF ATOMIZED ALUMINUM POWDERS

Gregory A.W. Sweet

Dr. D.P. Bishop


Master of Applied Science

ABSTRACT

Spark plasma sintering (SPS) is an emerging technology that has been successfully used to rapidly

consolidate numerous metallic powders into a fully dense condition. Processing in this manner is

particularly attractive for aluminum powders yet the majority of these studies have emphasized the

SPS response of expensive, exotic materials that are unsuitable for high volume manufacturing.

As such, the SPS response of low cost powders must be established if widespread commercial

inception of this technology is to be realized. To commence studies in this domain, conventionally

atomized aluminum powders were subjected to SPS processing. A number of process variables

were considered including heating rate, peak temperature, and hold time. The density, hardness,

microstructure and in select instances, tensile properties of consolidated products were then

assessed. Data confirmed that SPS was highly amenable to the consolidation of atomized powders

and was capable of producing fully dense products with advantageous mechanical properties

Single phase composition in the Li-Ni-Mn-O system with layered structure

Jing Li

Dr. Jeff Dahn


PhD

ABSTRACT

The energy density and cost of the lithium-ion batteries must be improved if electric vehicles are

to see a larger market share of consumer vehicles. The single phase layered compositions in the

Li-Ni-Mn-O system are an attractive alternative to current cathode materials such as LiCoO2. It is

possible to get a high capacity of ~200 mAhg-1 for these materials compared to ~150 mAhg-1 for

LiCoO2 and lower cost by replacing costly Co with inexpensive Mn. This study focuses on finding

and characterizing the single phase compositions in the layered region for better cathode materials

of lithium ion batteries.

Key words: Lithium ion batteries; Cathode; Lithium rich; Layered;

INFLUENCE OF BLENDED ELEMENTAL AND PREALLOYED ALUMINUM

ADDITIONS ON THE SINTERING BEHAVIOUR OF TITANIUM ALLOYS

Joannie Lapointe

Dr. Stephen Corbin and Dr. Kevin Plucknett


M.A.Sc. Candidate

ABSTRACT

This project, in collaboration with Automotive Partnership Canada, aims to determine efficient

and cost effective powder metallurgical (PM) based fabrication routes for the production of

titanium alloy automotive parts. New titanium-aluminum-iron alloys are regarded to be interesting

for the automotive industry as they can achieve the mechanical properties of more common

Ti6Al4V but contain lower cost Fe additions. The lowest cost PM route to produce these alloys is

through the use of blended elemental (BE) or master alloy (MA) additions to commercially pure

titanium (CP-Ti) powder. In-situ alloying of these additions during sintering is needed to produce

a uniform alloy composition and microstructure.

This presentation focuses on the sintering interaction between titanium and aluminum, using both

a MA titanium aluminide/titanium mixture, as well as BE titanium and aluminum. Particle size,

sintering time, and temperature were the primary parameters studied. DSC evaluation has been

conducted, along with sintered density evaluations, and microstructural observations.

Smaller BE or MA particle size was found to increase the rate of in-situ alloying and shrinkage

during sintering. The DSC was used to measure the shape of the exothermic peak caused by the

beta-to-alpha transformation during cooling. It was found that the peak shape was descriptive of

the quality of the extent of aluminum diffusion and the phase homogeneity in the sintered compact.

Scanning electron microscopy and energy dispersive X-ray spectroscopy led to quantitative

observations of the aluminum diffusion.

PARTICLE AGGLOMERATION EFFECTS ON EXPLOSIBILITY AND

EXPLOSIVE LIKELIHOOD

Josh Thistle

Dr. Paul Amyotte and Dr. Robert Ripley


MASc

Abstract

Use of powders in the nm-range in industrial settings has increased due to the unique properties

exhibited by materials in this particle size range. The increase in demand for nanopowders in

industry has subsequently sparked an increase in the need for an understanding of the safety

hazards associated with their use. A hazard that has received significant attention is exposure to

skin or inhalation in the lungs, and many guidelines can be found for the safe handling of

nanopowder dusts.

One important concern that cannot be neglected is the potential for nanopowder dust to form

explosible clouds. Numerous studies have been conducted on this topic for dust with diameters in

the micron range; this work has shown that a decrease in particle size corresponds to increased

explosion pressures and rates of pressure rise, as well as heightened ignition sensitivities. By

extrapolating these trends to nanopowders, one might expect extreme explosion severity and

ignition sensitivity for such materials.

High ignition sensitivity has indeed been measured for some nanopowders which display low

values of minimum ignition energy (MIE) and minimum ignition temperature (MIT). However,

the anticipated significant increase in explosion severity (overpressure and rate of pressure rise)

for nano-dusts has not been observed in recent laboratory studies. The inter-particle forces are

much stronger for fine dusts compared to dust in the micro-meter range, which leads to a greater

degree of particle agglomeration, which may help to explain the behaviour change when moving

into the nano-meter range.

An Experimental Study of the Influence of Porous Media on the Rate of Hydrate

Formation

Najlla Ali

Dr. Michael Pegg and Dr. Jan Haelssig

MASc


ABSTRACT

Gas hydrates (also called gas clathrates) are crystalline compounds formed from water and small

gas molecules like methane, ethane and carbon dioxide under conditions of high pressure and low

temperatures above the freezing point of water. In the natural environment, gas hydrates are

commonly found in the permafrost and deep ocean environment. Hydrate formation can also cause

serious processing problems in the oil and gas industry. For example, hydrate formation during

gas transportation can eventually plug pipelines, and thereby lead to economical and safety

problems. However, chemical additives can be used to overcome such plugging conditions in

pipelines. Moreover, hydrates can form under some conditions in gas and oil reservoir, which can

impact the flowing rate of the fluid into wellbore area. In order to avoid gas hydrate formation in

the reservoir it is necessary to understand the mechanism of hydrate formation in porous media.

Hydrate formation is strongly affected by temperature, pressure and the presence of porous media.

The goal of this work is to construct an experimental device that permits the investigation of the

effect of different size of porous media on the rate of hydrate formation. The experimental device

will include two glass windows for visual observations of the rates of hydrate formation. Further,

the system will be instrumented to allow indirect rate measurements based on heat evolution rates

as well as gas concentration measurements.

ENCAPSULATION OF ANTIDIABITIC SALMON PROTEIN HYDROLYSATES WITH

CHITOSAN COATED MILK FAT PHOSPHOLIPID LIPIDS

Zhiyu Li

Dr. Tom Gill, Dr. Allan Paulson

Food Science

Master of Science

ABSTRACT

Bioactive fish peptides have becoming important due to the awareness of the bioactive properties

found in the fish wastes. Low molecular weight protein hydrolysates have been found to provide

exceptional health benefits and have been developed into nutraceuticals. To optimize their

effectiveness, bioactive protein hydrolysates in nutraceuticals need to be protected, transported to

the target in the body, and then released in a controlled manner.

The focus of this research is to develop a polymer coated liposomal delivery system with milk fat

globule membrane (MFGM) phospholipids for oral administration. Atlantic salmon protein

hydrolysates (SPH), known to contain antidiabetic peptides, were encapsulated in chitosan-coated

liposomes prepared from MFGM phospholipids. A better understanding of this encapsulation

technique will contribute to the development of free-flowing powder and imparting functional

properties associated with the lipid membrane and polysaccharide that ease incorporation into a

variety of food products.

The size, zeta potential and entrapment efficiency (EE) were determined as a function of chitosan

coating concentration (0% - 0.6% (w/v)). The MFGM liposomes had an average size of 85-105

nm and a zeta potential of -54.5±1.3mV depending on the concentration of MFGM used (3, 5 or

10%). The zeta potential increased to +55mV with the increasing amount of chitosan

concentration. Below a critical chitosan concentration, large aggregates were formed and caused

phase separation. The chitosan coated liposomes were the most stable at 0.2%, 0.3% and 0.4%

chitosan concentration for 3%, 5% and 10% MFGM respectively. 10% MFGM samples showed

the greatest EE of 91.3±4.3%.

Further investigation is required to test 1) the release profile of the particles in simulated gastric

fluid and simulated intestinal fluid, 2) the stability of the coated particles.

The Study of Viscous Heating under Shear Flow by Using NMR Methods

Yun Chen

Dr. Gianfranco Mazzanti

Food Science

MSc Student

ABSTRACT

Shear rate has been found as a major factor affecting the process of crystallization. The shear flow

imposed on crystallizing fats produces heat because of the viscous nature of the suspensions. Under

shear flow condition, the rheology and the crystallization process of triglycerides are highly related

to the viscous heat generation and transfer, which is due to internal friction. At high shear rates,

there is a large temperature gradient across the oil, which is enough to produce a temperature in

the fluid several degrees higher that the control fluid. No significant increase in temperature at low

shear rates is found. NMR was described as a new method for studying the fat crystals. NMR will

not disturb the flow in the narrow gap of the experimental cell, and will allow us to measure the

temperature. My project will be utilizing NMR to plot the calibration curve of T2 as a function of

temperature, where T2 is the time for the signal to disappear in the transverse plane, or as the

characteristic time. Once T2 values for samples under shear flow are measured, the temperature

can be estimated. Then a model estimating the viscous heating of triglycerides will possibly be

built.

References:

Pilon et al, Metabolism 2011; 60:1122-1130

Laye et al, Journal of Food Science 2008; 73:N7-15

THE CHARACTERIZATION OF BUILDING-INTEGRATED MICROALGAE

PHOTOBIOREACTORS

Aaron Outhwaite

Dr. Mark Gibson and Dr. Stephen Kuzak


M.ASc

ABSTRACT

The photoautotrophic growth of microalgae within biological reactors presents many attractive

attributes when considered as a system for use within the built environment. Metabolic by-products

of habitation commonly considered as waste or pollution are in fact the exact resources commonly

utilized in microalgae photobioreactors. However, despite the apparent synergy between resource

availability within the built environment and resource demand for microalgae photobioreactor

systems, the characterization of a building-integrated microalgae photobioreactor (BIMP) system

has yet to be demonstrated in the literature.

The present work characterizes a BIMP system using a mathematical model based on multiple-

limitation kinetics for the microalgae species Chlorella Vulgaris. Here, the limiting factors include

light and temperature, which are characteristic to a specific built environment or enclosure, and

CO2 and nutrients, as they are generated by the occupant(s) there within. Concurrently, a prototype

has been developed for the purpose of simulating the real-time biomass yield and system

performance of the BIMP system in MATLAB. Preliminary simulation results show an acceptable

trend agreement between BIMP system biomass yield and published data for existing outdoor

microalgae production facilities.

CHARACTERIZATION OF BIOACTIVE PEPTIDES FROM SALMON PROTEIN

HYDROLYSATES

Jonathan Rolin

Dr. Tom Gill

Food Science

Ph.D

Salmon processing wastes can reach up to 50% of whole fish weight. In Atlantic Canada, this

represents approximately 13 million kg of material subsequently processed into low-value fish oils

and animal feeds annually (Statistics Canada, 2012). Protein-rich processing wastes are often

investigated for bioactivity properties. A low molecular weight Atlantic salmon protein

hydrolysate (SPH), derived from filleting wastes, has been shown to exhibit anti-diabetic

bioactivity. The SPH was tested in myocyte, adipocyte and hepatocyte tissue cultures as well as in

mouse feeding trials (Pilon et al., 2011) and exhibited the ability to alleviate the effects of type 2

diabetes at very low concentrations. Together, these findings suggest a suitable candidate for a

type 2 diabetes nutraceutical product. The objective of this work was to identify the bioactive

components of the SPH in order to facilitate the pilot-scale/industrial production of a hydrolysate

for human clinical trials.

To minimize complexity, a multidimensional chromatographic workflow was followed. Liquid

chromatography-mass spectrometry (LC-MS) was then performed to identify the peptides in each

fraction. Subsequent bioactivity testing was used to identify constituent bioactive peptides.

Ion-exchange chromatography (IEC) was reproducible, where repeated separations reported

relative coefficients of variation of 0.8% and 0.1% for the basic and acidic fractions, respectively.

IEC fractions were rich in amino acids of similar charge. The positively charged amino acids

represented 14.87% and 7.90% (p < 0.05) of the basic and acidic fractions, respectively and

negatively charged amino acids represented 20.47% and 38.70% (p < 0.05), of the basic and acidic

fractions, respectively.

The identification of bioactive peptide(s) in the SPH presents an opportunity for the production of

a novel nutraceutical derived from Atlantic salmon processing wastes for type 2 diabetes. This also

represents an opportunity for the aquaculture industry to benefit from the improved utilization of

their waste products.

SOURCE APPORTIONMENT OF THE AIR QUALITY ON SABLE ISLAND

Alex Hayes

Dr. Mark Gibson


MASc

ABSTRACT

Air pollution can have varied and severe effects on health, ecosystems, heritage, and climate. Its

impacts are also not limited to the point of release making it important to identify and quantify

sources of air pollution and their fate and transport globally. Most studies are conducted in urban

areas with few studies taking place at sea or near offshore oil and gas (O&G) production facilities,

resulting in a paucity of data in the marine environment. This study aimed to examine the different

sources of air pollution affecting the air quality on Sable Island with the aim of better

understanding the impacts of emissions from nearby offshore O&G activities and continental

outflow. Air pollution data obtained from Sable Island between May 7th and October 30th of 2013

was used to perform statistical analysis, source apportionment, and meteorological analysis. The

air pollutants measured were non-methane hydrocarbons, black carbon (BC), hydrogen sulphide

(H2S), nitrogen oxides (NOx), nitrogen monoxide (NO), nitrogen dioxide (NO2), ozone (O3), fine

airborne particles below 2.5 microns (PM2.5), and sulphur dioxide (SO2). Temporal trends in these

air pollutants and source apportionment will be presented.

EFFECT OF MICROSTRUCTURE ON TRIBOLOGICAL PROPERTIES OF

AUTOMOTIVE ALUMINIUM-SILICON ALLOYS UNDER LOW LOAD CONDITION

Avijit Sinha

Dr. Zoheir Farhat


MASc

ABSTRACT

Aluminum-silicon alloys have inherent advantages of being lightweight, high specific strength and

good heat transfer ability. It is suitable for manufacturing clutch housings and piston in the

automotive industry. The structure and properties of these alloys are very much dependent on the

composition of the alloy, surface modification and heat treatment. These alloys have been

fabricated by powder metallurgy techniques in which porosity is a common feature. The presence

of pore is responsible for decreasing effective load bearing cross sectional area and acts as stress

concentration site for strain localization and damage, decreasing both strength and ductility. In this

study, different levels of porosity were induced by varying the amount of lubricant during powder

compact and then the effect of porosity on wear damage and the types of wear mechanisms were

investigated.

A REVIEW OF BUBBLE DRAG CORRALATIONS APPLICABLE AT THE

OPERATIONAL CONDITIONS OF THE LC-FINER TM

Chris Lane

Dr. A. Donaldson


Ph.D.

ABSTRACT

The LC-FinerTM is a resid hydroprocessor technology which operates at high pressures (12 MPa)

and temperatures (440 C). Current predictions of gas holdup in these ebullated bed reactors are

lower than the observed gas holdup during operation. This high gas holdup is attributed to

internally recycled gas bubbles (McKnight et al., 2008). Modeling the fluid dynamics in the LC-

FinerTM can provide insights for geometry and operation optimization thereby reducing gas holdup

and increasing overall reactor efficiency. However, modeling a multi-phase separation process

poses many current challenges, one of which is using a validated drag correlation. An accurate

prediction of the drag and momentum coupling between phases is needed to provide confidence

in the CDF results. This work presents a comprehensive review of current drag closures in

literature valid at the operating conditions and phase fractions found in the LC-FinerTM freeboard

region. Special consideration is given to the extendibility of these correlations to very high phase

fractions (>40%). In addition, recommendations are provided for future experimental verification

of the correlations with a focus on quantifying drag model accuracy at very high phase fractions.

AN IMMERSED BOUNDARY MODEL FOR SIMULTANEOUS HEAT AND MASS

TRANSFER

Devin O'Malley

Dr. Jan Haelssig


MASc.

ABSTRACT

Multiphase systems are prolific in modern industry, particularly as methods of component

separation. Absorption, distillation, evaporation, condensation and even some reactors rely on a

phase boundary. To accurately predict performance of heat and mass transfer at the interface is

imperative to the modeling and economical design of industrial separation units. Normally,

determining these heat and mass transfer rates are based upon empirical correlations or studies,

requiring lumped parameter estimation. These can be both expensive and suffer from severe losses

in accuracy. As an alternative solution, computational fluid dynamics (CFD) can be used to model

these systems, and requires at least one computer to perform a series of complicated calculations

at the sole expense of time.

A model was designed that utilizes volume of fluid (VoF) methodology in order to track phases

dynamically, and solve transport equations for heat and mass transfer. Using an open source

software as the base, algorithms were added to approximate the interfacial area and its position.

Knowing that, the actual gradients can be calculated across the immersed boundary and used as

source terms which act like boundary conditions within the system itself.

The model was tested using a one dimensional Stefan tube problem, a two dimensional channel

flow case and a three dimensional droplet in microgravity. The primary goal was to test the area

reconstruction algorithm and the capacity of the solver to predict mass transfer, as the heat transfer

by evaporation is dependent upon it. The results of the work are matched with analytical and

derived solutions, and lead to future work on refinement of the model and the treatment of

temperature dependent properties.

SILVER-BASED LIQUID-LIQUID EXTRACTION OF EPA/DHA FROM FISH OIL IN

MINIFLUIDIC SLUGFLOW REACTOR

Kirubanandan Shanmugam

Dr. Adam Donaldson



ABSTRACT

Liquid – Liquid extraction utilizing minichannels has attracted an increasing interest in recent

years in the field of Separation of Omega 3 PUFA from fish oils. The performing extraction in

minichannel offer enhancement of Interfacial area enhanced mass transfer and large Volume

&Surface ratio. Furthermore, the reduction in area of the channel minimize the diffusion distance

and provides internal circulation in the fluids that enhance mixing between two immiscible phase.

This work explores the development of extraction processes for Omega 3 PUFA in minifluidic

channel. In order to develop pharmaceutical and food grade Omega 3 PUFA, efficient extraction

and concentration methods have been developed and are continually reviewed for improvement.

Since fish oils are complex mixtures of fatty acids with various chain lengths and degrees of

unsaturation, separation of individual fatty acids is difficult for production of highly concentrated

Omega 3 components. The minifludics extraction of Omega 3 PUFA has been attempted in

minifluidic experimental set up. The experimental data for practical extraction yields and

concentration data are determined for a 1/16” ID mini-channel with slug flow pattern, and

compared to available results from idealized system like batch continuous stirred tank reactor. As

a result, the performance of the mini-fluidic system and CSTR are also comparable in terms of

equilibrium concentrations. It is observed that the performance of extraction and yield appear quite

promising. However, the stratified flow in the minichannel is observed due to the reduction of

interfacial tension of idealized solvent mixture at 10 °C. It is found that equilibrium has been

reached in less than 36 seconds in the mini-fluidic reactor at 10°C than idealized systems, which

suggests shorter length flow path could be used. Based on preliminary investigation, the stainless

steel based plate and frame minufluidic reactor construct as experimental setup in order to bring

slug flow in the channel is under development and construction for extraction processes.

RAISING AWARENESS OF COMBUSTIBLE DUST HAZARDS

Morgan Worsfold

Dr. Paul Amyotte


MASc

ABSTRACT

The hazards associated with combustible dusts are not well known, particularly when compared

to a somewhat similar hazard, flammable gases. Given the results of dust explosions, a

communication strategy framework is being developed for the purpose of improving safety

awareness of combustible dust hazards among a diverse audience. The primary resources currently

used to communicate knowledge about dust explosions are journal publications and conference

proceedings. The knowledge presented in these sources would need to be translated and presented

in a range of formats if it were to become relevant and available to the varied identified target

groups. Different groups require different approaches in terms of the complexity and depth of the

information, its format, and the method of delivery, among other factors. In order to communicate

and translate dust explosion hazard expertise across such a varied audience, it is useful to take an

information management approach to understanding how to best communicate information to

diverse groups to their individual benefits. This presentation will explore information management

strategies as applied to the specific case of dust explosions. These have been implemented in the

development of an educational module on combustible dust hazards for undergraduate engineering

students.

Crack generation in TiC-316L steel cermets using Vickers

indentation

Chenxin Jin

Dr. Kevin Plucknett


PhD

Abstract

Cermets are composite materials that combine hard, brittle ceramics with a ductile metal phase.

Compared with conventional hardmetals such as WC/Co, cermets are lighter in weight while

maintaining high strength, toughness, good wear and corrosion resistance. Due to its high melting

point and low density, TiC is used in a variety of applications, such as bearings, drawing dies, etc.

In the present work, stainless steel binders (grade 316L) have been utilised for the preparation of

TiC-based cermets, with the steel content varied from 5 to 30 vol. %. Samples were fabricated

using a simple vacuum melt-infiltration procedure, at temperatures between 1475°C and 1550°C,

held for up to 240 minutes. It is demonstrated that a core-rim structure arose for the cermets when

sintered at 1550°C for 240 minutes, with accommodation of selected steel constituents into the rim

of the TiC grains. The Vickers indentation response of these materials has been assessed. Two

primary indentation-cracking patterns may arise, namely median cracks or Palmqvist cracks,

which relates to the volume fraction of ductile metal binder present. In particular, this work

assesses the influence of the steel binder content and grain size on the Vickers indentation

response, using sequential polishing to determine the sub-surface crack patterns. Preliminary use

of a focused ion beam microscope for evaluation of the crack path will also be discussed.

AN INVESTIGATION OF THE VOLATILE ORGANIC COMPOUND SPECIES (VOCs)

CONTENT OF BEER AND FORMATION PATHWAY IN AGED BEER

Priyanka Mehra

Dr. Mark Gibson

Food Science

Master of Science

ABSTRACT

The characterization of the volatile organic compound species (VOCs) content of beer is of great

importance in modern brewing industry for a number of reasons. Knowledge of the VOC content

can help with the selection of raw materials, yeast strains, fermentation conditions, brewing

procedures, quality of beer and product development. A lack of flavor stability is of great concern

to brewers as this can impact consumer satisfaction and ultimately product sales. The increase in

the concentration of VOCs in the beer during storage can result in the development of undesirable

flavors and aromas in the beer, e.g. cardboard, fruity, caramel, ribe and sweet. For example, the

increase in the concentration of (E)-2-nonenal, which imparts a cardboard flavour to the ageing

beer, is important from an analytical point of view. A major focus of the brewing industry is to

control the concentration of the VOCs in the beer in order to extend shelf life. This study will

involve a comparative study of VOCs in finished beer, naturally aging beer (6-months) and

forcibly aged beer (incubation for 4 weeks at 40°C). The analytical purge-trap-thermal desorption

technique will be used for the extraction and enrichment of VOCs from the beer sample and

delivering them to a gas chromatograph/ mass spectrometer (GC/MS) for separation, identification

and quantification. The purpose of the study is to detect and control the VOCs in the beer which

have negative effects on taste and aroma. The processing conditions will be manipulated by hit

and trial method in order to control the VOCs in the finished beer. The experiments that will be

conducted in this study will help the brewers to improve flavour stability of their beer and thereby

extending the shelf life and consumer satisfaction of their product.

EXTRACTION OF ANTIOXIDANTS FROM DATE PALM FRUIT (PHOENIX

DACTYLIFERA)

Rasha Al udhaib

Dr. Abdel E. Ghaly


MASc

ABSTRACT

The date palm (Phoenix dactylifera L.) has been an important plant in arid and semi-arid areas for

centuries. In fact, cultivated dates are a stable food source in many countries, playing significant

roles not only in the people’s nutrition, but also in their economy. Due to their nutritional value

and ease of transportation and storage, dates have had a very important influence on the history of

the Middle East. The world’s production of dates has been growing due to the increase in

population and consumer demand. However, lots of dates are not suitable for human consumption

for several reasons including: low quality, contamination by insect and hard texture. In some places

they are used as animal feed. There has been a significant amount of interest in recent years

regarding the properties of antioxidants found in plants particularly those used in traditional

medicines. The use of antioxidant supplements has shown some improvement in health. Many

studies show that consumption of a lot of fruit and vegetables (rich in antioxidants) is related with

lower cancer rates. These compounds have been found to neutralize free radicals inside the body

which originate from metabolic as well as external processes. Free radicals are dangerous because

they trigger chemical chain reactions within the body that damage or kill cells and as such they

have been linked to a number of diseases. The aim of this study is to investigate the possibility of

extracting antioxidants from five different popular Verities (Barhi, Sukkari, Majhol, Khalas and

Ajwa) of date fruits from Saudi Arabia. The result of this study will help in the medical failed.

Saudi Arabia is the world’s second-largest producer of dates in 2011, growing 16% of the total

global production. Saudi Arabia has more than 23.7 million date palm trees cultivated on more

than 156,000 hectares, producing about 992,000 tonnes of dates annually.

PROTON NMR CAN BE USED TO MEASURE EPOXIDES DERIVED FROM LIPID

OXIDATION

Wei Xia

Dr. Suzanne Budge

Food Science

Master of Science

ABSTRACT

Hydroperoxides and carbonyl compounds are typically viewed as the main products of lipid

oxidation. Recently, epoxides have also been suggested as important intermediates but there is a

lack of suitable methods for their determination in oxidized oils. Here we describe a method to

quantify epoxide yield during lipid oxidation using 1H NMR. To investigate the chemical shifts of

mixed epoxides derived from polyunsaturated fatty acids, fresh fish oil was epoxidized using

formic acid and hydrogen peroxide. The chemical shifts of mixed epoxides in epoxidized fish oil

were found to be between 2.9-3.3 ppm. The peaks associated with glycerol remained constant

during both oxidation and epoxidation of fish oil allowing them to be used as an internal reference

for the quantification of epoxides. Oil samples with different epoxide concentration were made

and standardized using the AOCS method for oxirane oxygen. These were analyzed by 1H NMR

under standard conditions to generate a standard curve. To demonstrate the utility of the method,

commercial oils were then oxidized under a variety of conditions and epoxides were determined

by 1H NMR.

CORROSION BEHAVIOUR OF ALUMIX 123 POWDER METALLURGY

ALUMINUM ALLOY

William D. Judge

Dr. D.P. Bishop and Dr. G.J. Kipouros



ABSTRACT

Aluminum powder metallurgy (P/M) products compete with traditional ingot metallurgy products

(I/M) for specific applications. P/M alloys offer the advantage of near net shape production.

However, the corrosion behaviour needs to be evaluated.

In this work electrochemical experiments on both AA2014 (I/M) and Alumix 123 (P/M) alloys are

performed with the aim to correlate the corrosion behaviour to the production technique.

Electrochemical measurements such as Tafel extrapolation (TE), Cyclic Polarization (CP), Linear

Polarization (LP), and Stair-step Polarization (SP) are performed on the alloys immersed in

3.5wt% NaCl solutions. Corrosion products are characterized by Scanning Electron Microscopy

(SEM), Energy Dispersive Spectroscopy (EDS), Wavelength Dispersive Spectroscopy (WDS),

and X-ray Diffraction (XRD).

EFFECT OF TEMPERATURE ON THE WIDE ANGLE X-RAY DIFFRACTION OF

NANOCRYSTALLINE TRIGLYCERIDES

Xiyan Deng


Food Science

MSc.

ABSTRACT

Triglycerols (TAG), the main component of edible fats, have a rich and complex polymorphism.

The phase behavior of TAG is strongly influenced by many factors during crystallization, e.g.

temperature, shear rate and cooling rate. Often the best texture of a specific food such as chocolate

is obtained by forming one particular polymorph in preference to others.

As a powerful tool, X-ray diffraction is used to monitor polymorphic form and the transformations

of various TAG mixtures. Due to the peculiar size of intermolecular distances in nanocrystalline

triglycerides, their diffraction patterns are naturally divided into two groups – Small angle x-ray

diffraction patterns (SAXD) and wide angle x-ray diffraction patterns (WAXD). SAXD patterns

give information about the number of phases formed and the amount of each phase formed as

crystallization proceeds. WAXD patterns give information about the lateral distances between two

hydrocarbon chains in a crystal, which are characteristic of a particular polymorph.

It was noticed in previous studies that the peak position of WAXD patterns is affected by the

temperature. In order to observe this effect quantitatively, pure materials, such as trilaurin and

tristearin, and the dry blends mixed by two pure materials with different proportion are analyzed

in this experiment. The samples were melted at high temperature to erase the crystal memory and

then tempered to produce the β polymorph crystals in capillaries. The crystallized samples were

kept at different temperatures for at least 100 minutes and the WAXD patterns were obtained. This

presentation describes how different WAXD peaks change their position as the temperature

changes.

EFFECT OF TEMPERATURE TIME COMBINATIONS ON THE CRYSTAL

MEMORY OF TRIGLYCERIDES

Yujing Wang


Food Science Program

Master of Science

Abstract

Fats are mainly composed of triglycerides (TAGs) which occur in different polymorphic phases

characterized by unique molar heat capacity and enthalpy values. These values vary between the

crystalline forms due to the different crystalline structure of each form. The α form, for instance,

has the least crystalline packing and therefore the highest heat capacity and least enthalpy. The

opposite characteristics are observed in the β form due to its densely packed arrangement. The

distribution and composition of the polymorphic types in the crystalline structure largely

determines the final sensory and appearance qualities of the products. When fats are melted, they

tend to retain, or “remember”, the compositional and nano-structural organization they had when

they were crystalline. Upon re-crystallization, this often produces crystalline structures with

undesirable end qualities. This phenomenon is known as crystal memory. So far, there is no clear

mechanism for this occurrence. We propose that the formation of multimers and compositional

gradients, if not avoided by long enough heating, will influence the subsequent crystallization

behavior. To ensure that a melted fat sample is homogeneously mixed before starting crystallizing

it, one must apply to it an adequate combination of time and temperature. This will ensure that all

the crystals are melted and that proper diffusion mixing occurs. We tested our hypothesis

determining the combination of time-temperature required to obtain well mixed liquid prior to

crystallization of a blend of trilaurin and tristearin. Time-resolved synchrotron x-ray diffraction

patterns at small and wide angles were obtained for the liquid, and their characteristic position and

width showed the degree of separation of both TAGs in the liquid. These results were compared

to thermal measurements conducted with TA Instruments differential scanning calorimeter, DSC

Q100.

THE AQUEOUS CORROSION RESPONSE OF TIC AND TI(C,N) CERMETS WITH

NI3AL-BASED BINDERS

Zhila Memarrashidi

Dr. Kevin Plucknett


MASc

ABSTRACT

In the present study, the aqueous corrosion behavior of TiC and Ti(C,N) based cermet materials

has been investigated, using a range of Ni3Al-based intermetallic binders. Cermets were prepared

using a reaction-sintering route, with 30 vol. % binder, achieving densities in excess of 99% of

theoretical. Measurement of the open circuit potential was used to determine the equilibrium

electrochemical potential. The potentiodynamic and cyclic polarization responses of the cermet

materials have been determined, with Tafel extrapolation used to determine the rate of corrosion

for each composition. Inductively coupled plasma optical emission spectrometry was then applied

to analyse the post-test corrosion solutions, in order to determine elemental species liberated from

the samples during corrosion testing. The effects of the corrosive environments were also assessed

using scanning electron microscopy. It was demonstrated that selective attack of the binder occurs,

and the extent of corrosion and primary mechanism depends on the Ni3Al alloy composition.

The faculty, students and staff of Process Engineering and Applied Science

would like to thank the following sponsors for their generous contribution to this

year’s Graduate Research Symposium

dalhousie university - 2014 peas graduate symposium book ......the aqueous corrosion response of tic...

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