M. Papini's research while affiliated with Ryerson University and other places

Publications (221)

Article
Full-text available
Strength degradation of aluminum oxide under successive impingements of small particles is a destructive process occurring in many applications, especially when using alumina coatings to improve the solid particle erosion resistance of metals. Solid particle erosion of alumina has been mostly studied either experimentally or analytically, and the e...
Article
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The most common complication of median sternotomy surgery is sternum re-separation after sternal fixation, which leads to high rates of morbidity and mortality. The adhered sternal fixation technique comprises the wiring fixation technique and the use of bio-adhesives. Adhered sternal fixation techniques have not been extensively studied using fini...
Article
Background: Glass polyalkenoate cements (GPCs) are bio-adhesives which consist of ionomeric glass particles embedded in a poly-salt matrix. These materials have been used in dentistry and orthodontics extensively but are presently being optimized as bone putties for orthopedic applications. Objective: This study utilized a patented ionomeric gla...
Article
Traditionally, photolithography and soft-lithography methods have been used to fabricate micro-molds for casting polymeric microfluidic chips. Because of the time and cost involved, there has been motivation to fabricate microfluidic micro-molds using other techniques. A previous study utilized stainless steel masks cut using abrasive waterjet micr...
Article
Understanding the failure modes and the fracture resistance is critical in evaluating the performance of an adhesive for sternal fixation. In this paper, a fracture mechanics testing methodology was used to assess the adhesion of a bioactive glass-based adhesive to bovine bone in terms of a measured mode I critical strain energy release rate (GIC)....
Article
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Poly(methyl methacrylate) (PMMA) is used to manage bone loss in revision total knee arthroplasty (rTKA). However, the application of PMMA has been associated with complications such as volumetric shrinkage, necrosis, wear debris, and loosening. Glass polyalkenoate cements (GPCs) have potential bone cementation applications. Unlike PMMA, GPC does no...
Article
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Wire cerclage remains the standard method of care for sternal fixation, following median sternotomy, despite being beset with complications. An emerging treatment option has been to augment the wires with an adhesive. A patented ionomeric glass (mole fraction: SiO 2 :0.48, ZnO:0.36, CaO:0.12, SrO:0.04) has been used to formulate GPC+, a glass polya...
Article
Despite the relatively high erosion resistance of elastomers, few studies have considered using them as reinforcements for polymer composites. This study investigated the erosion of rubber particle-reinforced epoxy composites by angular silicon carbide particles. The erosion rates were found to be significantly lower than the neat epoxy for all tes...
Article
c o m p u t e r m e t h o d s a n d p r o g r a m s i n b i o m e d i c i n e 1 0 7 (2 0 1 2) 315-326 Optimization Nonlinear biphasic poroviscoelastic fibre-reinforced Finite element Friction Human a b s t r a c t An inverse method was developed to determine the material constitutive parameters of human articular cartilage from stress relaxation in...
Article
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A nonlinear biphasic fiber-reinforced porohyperviscoelastic (BFPHVE) model of articu-lar cartilage incorporating fiber reorientation effects during applied load was used to predict the response of ovine articular cartilage at relatively high strains (20%). The con-stitutive material parameters were determined using a coupled finite element-optimiza...
Article
Background: Conventional models to evaluate degenerated cartilage do not consider nonlinear permeability and proteoglycan viscous effects. Some models also utilize spring elements to represent the viscous effects of the fibers, thus application tothe modeling of nonuniform deformations such as those that occur in indentation tests. The purpose of t...
Article
Inertial microfluidics has been used in recent years to separate particles by size, with most efforts focusing on spiral channels with rectangular cross sections. Typically, particles of different sizes have been separated by ensuring that they occupy different equilibrium positions near the inner wall. Trapezoidal cross sections have been shown to...
Article
Size-based particle separation using inertial microfluidics in spiral channels has been well studied over the past decade. Though these devices can effectively separate particles, they require a relatively large device footprint with a typical outer channel radius of approximately 15 mm. In this paper, we describe a microfluidic device with a footp...
Article
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Poly(methyl methacrylate) (PMMA) bone cement is used as a minor void filler in revision total knee arthroplasty (rTKA). The application of PMMA is indicated only for peripheral bone defects with less than 5 mm depth and that cover less than 50% of the bone surface. Treating bone defects with PMMA results in complications as a result of volumetric s...
Article
Glass polyalkenoate cements (GPCs) are under investigation as potential bone adhesives, as they may provide an alternative to polymethylmethacrylate-based cements. GPCs containing strontium (Sr) and zinc (Zn) in place of aluminium (Al) are of particular interest because these ions are known stimulators of osteoprogenitor differentiation. GPCs have...
Article
An smooth particle hydrodynamics/finite element (SPH/FEM) model was developed to simulate the erosion of zirconia particle‐reinforced epoxy composites, due to the overlapping impacts of angular particles at both perpendicular and oblique incidences. For each composite target, multiple sub‐volumes, each having their own random reinforcement distribu...
Article
Microfluidic lab-on-a-chip devices are usually fabricated using replica molding, with poly(dimethylsiloxane) (PDMS) casting on a mold. Most common techniques used to fabricate microfluidic molds, such as photolithography and soft lithography, require costly facilities such as a cleanroom, and complicated steps, especially for the fabrication of thr...
Article
Microfluidic lab-on-a-chip devices are usually fabricated using replica molding, with poly(dimethylsiloxane) (PDMS) casting on a mold. Most common techniques used to fabricate microfluidic molds, such as photolithography and soft lithography, require costly facilities such as a cleanroom, and complicated steps, especially for the fabrication of thr...
Article
Microfluidic lab-on-a-chip devices are usually fabricated using replica molding, with poly(dimethylsiloxane) (PDMS) casting on a mold. Most common techniques used to fabricate microfluidic molds, such as photolithography and soft lithography, require costly facilities such as a cleanroom, and complicated steps, especially for the fabrication of thr...
Article
Microfluidic lab-on-a-chip devices are usually fabricated using replica molding, with poly(dimethylsiloxane) (PDMS) casting on a mold. Most common techniques used to fabricate microfluidic molds, such as photolithography and soft lithography, require costly facilities such as a cleanroom, and complicated steps, especially for the fabrication of thr...
Article
Microfluidic lab-on-a-chip devices are usually fabricated using replica molding, with poly(dimethylsiloxane) (PDMS) casting on a mold. Most common techniques used to fabricate microfluidic molds, such as photolithography and soft lithography, require costly facilities such as a cleanroom, and complicated steps, especially for the fabrication of thr...
Article
The demand for metallic micro-molds that can be used for inexpensive mass production of polymeric microfluidic chips is increasing. Existing manufacturing techniques such as soft-lithography and photolithography can require multiple time-consuming steps, especially when the aim is to create three-dimensional features. In this study, the feasibility...
Article
Titanium‐containing borate bioactive glass scaffolds (0, 5, 15 and 20 mol%, identified as BRT0, BRT1, BRT3 and BRT4) with a microstructure similar to that of human trabecular bone, were prepared and evaluated in vitro for potential bone loss applications in revision total knee arthroplasty (rTKA). Methyl thiazolyl tetrazolium (MTT) cell viability a...
Article
Full-text available
The solid particle erosion of polymers occurs in a wide variety of industries and has been extensively studied experimentally. However, numerical models capable of accurately simulating the associated material removal mechanisms and predicting erosion rate do not yet exist. In this paper, a coupled smoothed particle hydrodynamics (SPH)/finite eleme...
Article
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Poly(methyl methacrylate) (PMMA) is widely used in joint arthroplasty to secure an implant to the host bone. Complications including fracture, bone loss and infection might cause failure of total knee arthroplasty (TKA), resulting in the need for revision total knee arthroplasty (rTKA). The goals of this paper are: (1) to identify the most common c...
Article
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Interest in strontium (Sr) has persisted over the last three decades due to its unique mechanism of action: it simultaneously promotes osteoblast function and inhibits osteoclast function. While this mechanism of action is strongly supported by in vitro studies and small animal trials, recent large-scale clinical trials have demonstrated that orall...
Article
Abrasive jet micro-machining (AJM) uses compressed air carrying abrasive solid particles to micro-machine a variety of features into surfaces. If the feature sizes are less than the size of the abrasive jet footprint, then a patterned erosion-resistant mask is used to protect the substrate material, leaving exposed areas to define the features. Pre...
Article
A titanium-containing borate glass series based on the system (52-X) B2O3-12CaO-6P2O5-14Na2O-16ZnO-XTiO2 with X varying from 0, 5 and 15 mol% of TiO2 incorporated, identified as BRT0, BRT1 and BRT3, respectively, were used in this study. Scaffolds (pore sizes, 165-230 μm and porosity, 53.51-69.51%) were prepared using a polymer foam replication tec...
Article
Full-text available
Stainless steel wires are the standard method for sternal closure because of their strength and rigidity, the simplicity of the process, and the short healing time that results from their application. Despite this, problems still exist with sternal stability due to micromotion between the two halves of the dissected and wired sternum. Recently, a n...
Article
The solid particle erosion of a spherical alumina particle-reinforced epoxy matrix composite was investigated. Three dimensionless parameters were demonstrated to play key roles in the erosion resistance: r1, the ratio of the abrasive to reinforcement particle size; r2, the ratio of the abrasive particle size to the average edge-to-edge distance be...
Article
In 2014-2015, 61,421 total knee arthroplasties (TKAs) were performed in Canada; an increase of about 20% over 2000-2001. Revision total knee arthroplasties (rTKAs) accounted for 6.8% of TKAs performed between 2014 and 2015, and this is estimated to grow another 12% by 2025. rTKAs are typically more complicated than primary TKAs due to the significa...
Article
The abrasive water jet micro-machining of high aspect ratio free-standing structures such as fins used in heat sinks was investigated. The aim was to fabricate the maximum number of fins per unit length with the highest aspect ratio into Al6061-T6, in order to maximize heat transfer potential. Adjacent straight channels at various offsets were mach...
Article
To decrease the size of the eroded footprint resulting from abrasive air jet machining, the aerodynamic focusing of an abrasive particle jet was investigated. Using a slot nozzle abrasive jet, the best focusing employed a pair of bounding air jets tilted 60° to the abrasive jet, at an impingement height of approximately 10% of the standoff distance...
Article
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The resolution of features machined with abrasive slurry jets is dependent on the diameter of the erosion footprint on the workpiece and on the stability of the jet. Previous work has shown that the footprint size decreases, but the jet oscillation increases, with increasing polymer concentration. The present study investigated the effect of nozzle...
Article
Part I of this two-part paper presented an inverse technique to sculpt high aspect ratio (AR) micro-channel cross-sections of desired topography. In this paper, the methodology is experimentally verified for a variety of topographies machined in both brittle and ductile erosive materials. Micro-channels with trapezoidal and semi-circular cross-sect...
Article
Control of the cross-sectional shape of micro-channels may be of interest in micro-heat-sinks, microfluidic particle sorting, and micro-machine lubrication applications. It has been previously shown that inverse methods can be used to determine the abrasive jet micromachining (AJM) traverse speed and path required to sculpt desired micro-channel to...
Article
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Part I of this two-part paper presented mixing chamber conditions and jet characteristics in a high-pressure abrasive slurry jet micro-machining (HASJM) system. The present paper describes the modeling of the slurry entrainment process within the mixing chamber and mixing tube of the nozzle using computational fluid dynamics (CFD) and shows how the...
Article
Background: Cerclage wires remain the current standard of care following median sternotomy, despite significant complications including dehiscence and infection. This study uses a human cadaveric model to investigate the use of glass polyalkenoate cements formulated from two glasses, A (mole fraction: SiO2:0.48, ZnO:0.36, CaO:0.12, SrO:0.04) and B...
Article
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Techniques to enhance the performance of a high-pressure abrasive slurry jet micro-machining process (HASJM) were investigated by altering the conditions within the jet. The slurry flow rate was controlled using six inlet tubes (cross-sectional areas of 0.2, 0.46, 1.27, 1.77, 3.08, and 4.51 mm²), and was found to have a large effect on the conditio...
Article
Abrasive water jets (AWJs) have recently been used to mill unmasked features as narrow as 600μm. This paperinvestigated the use of metal masks in order to decrease this minimum possible feature width in Al6061-T6 andborosilicate glass. Although there was under-etching on the channel sidewalls below the mask edges, it wasnevertheless found that mask...
Article
During solid particle erosion, a transient incubation period can occur due in part to particle embedment into the target. This paper presents a novel three-dimensional smoothed particle hydrodynamics model of the impact and embedding of successive bursts of 362 μm angular SiC abrasives onto a 6061-T6 aluminum target. The predicted embedment agreed...
Article
In both abrasive water jet (AWJ) and high pressure abrasive slurry jet (HASJ) machining, garnet abrasive particles are mixed with water and the resulting jet can contain particles travelling with a wide range of velocities. Previous investigations have suggested that a dual disc anemometer (DDA) can be used to provide an assessment of the average p...
Article
Delamination is a common defect when abrasive waterjet (AWJ) cutting composite laminates. This paper presents experimental and numerical results used to characterize delamination when AWJ cutting a carbon-fiber/epoxy laminate. A fluid-structure interaction model was used to simulate the AWJ cutting. The structural domain used cohesive zone modeling...
Article
Abrasive waterjet (AWJ) piercing of composite laminates typically generates interlaminar delamination due to the hydraulic shock (‘water hammer’) associated with liquid jet impact. This paper extends previous liquid jet impact literature by examining the effects of hydraulic shock on an anisotropic carbon-fiber/epoxy laminate using finite element a...
Article
This paper investigates the use of air-driven abrasive jets as a lathe and as a means of machining helical patterns into rotating rods. The first part of the paper presents a model for the prediction of material removal during the machining of rotating and translating ductile (PMMA) and brittle (glass) rods using abrasive jet micromachining (AJM)....
Article
Full-text available
Objective To develop a surgical technique for percutaneous upper extremity fracture fixation using a novel glass-based adhesive. Methods Three intact upper extremity cadaveric specimens with undisturbed soft tissues were obtained. Two were used to model a wrist fracture, and the third to model a proximal humerus fracture. Fractures were produced u...
Article
It has been reported that the adhesion of bioactive glass coatings to Ti6Al4V reduces after degradation, however, this effect has not been quantified. This paper uses bilayer double cantilever (DCB) specimens to determine GIC and GIIC, the critical mode I and mode II strain energy release rates, respectively, of bioactive coating/Ti6Al4V substrate...
Article
Abrasive slurry-jet micro-machining (ASJM) is a low-cost and relatively quick alternative for the selective removal of metallic layers compared to conventional processes such as chemical-mechanical planarization (CMP). The present study used a computational fluid dynamics (CFD)-aided methodology with over-lapping ASJM channel machining to predict t...
Article
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In an attempt to combat the possibility of bacterial infection and insufficient bone growth around metallic, surgical implants, bioactive glasses may be employed as coatings. In this work, silica-based and borate-based glass series were synthesized for this purpose and subsequently characterized in terms of antibacterial behavior, solubility and cy...
Article
Bioactive glasses have been used as coatings for biomedical implants because they can be formulated to promote osseointegration, antibacterial behavior, bone formation, and tissue healing through the incorporation and subsequent release of certain ions. However, shear loading on coated implants has been reported to cause the delamination and loosen...
Article
Surface roughness is a valuable metric when assessing abrasive waterjet machining (AWJM) cut quality. This paper presents 2D and 3D models capable of predicting the surface roughness during abrasive waterjet (AWJ) trimming of composite substrates. The composites used were a carbon-fiber laminate with an epoxy resin and a random oriented carbon-fibe...
Article
Abrasive slurry jet micro-machining (ASJM) was used to machine channels in glass, PMMA, zirconium tin titanate, and aluminum nitride. The channel roughness was measured as a function of the ASJM process parameters particle size, dose, impact velocity, and impact angle. The steady-state roughness of the channels was reached relatively quickly for ty...
Article
Abrasive jet micro-machining (AJM) uses a high speed jet of particles to mechanically etch features such as micro-channels into a wide variety of target materials. Since the resulting air-particle jet is divergent, erosion resistant masks are required for patterning. Because of their ease of application, 50 and 100 μm thick commercially available u...
Article
This work considered the effect of increasing Strontium ion (Sr²⁺) content on the structure of a series of glasses based on the B2O3-P2O5-CaCO3-Na2CO3-TiO2-SrCO3 series and their resultant fracture toughness when coated onto a surgical metal substrate. Six glasses with increasing Sr²⁺ content (0 to 25 mol%) were synthesized and subsequently charact...
Article
Channels with non-conventional shaped cross sections have applications especially in microfluidics, where flow and heat transfer characteristics may depend on shape. Most microfabrication technologies capable of sculpting desired micro-channel shapes are limited in the range of shapes they can produce. Abrasive jet micromachining (AJM) uses a jet o...
Article
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Silica-based and borate-based glass series, with increasing amounts of TiO2 incorporated, are characterized in terms of their mechanical properties relevant to their use as metallic coating materials. It is observed that borate-based glasses exhibit CTE (Coefficient of Thermal Expansion) closer to the substrate’s (Ti6Al4V) CTE, translating into hig...
Conference Paper
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Abrasive waterjet (AWJ) performance and application is heavily dependent on nozzle geometry and operating conditions. The current research presents a novel technique, using genetic algorithms (GAs), to optimize a nozzle design and operating conditions for abrasive waterjet machining (AWJM) operations. The optimization program uses a one-dimensional...
Article
A computational fluid dynamics (CFD) procedure is presented for the prediction of the erosive footprint size in abrasive jet micro-machining (AJM). The CFD-obtained footprints were in good agreement with those measured experimentally. The footprint was found to be due to both primary particle impacts in the conical plume emanating from the nozzle,...
Article
This work considered the effect of both increasing additions of Strontium (Sr(2+)) and incubation time on solubility and both antibacterial and osteo-stimulatory effects of a series of glasses based on the B2O3-P2O5-CaCO3-Na2CO3-TiO2-SrCO3 series. The amorphous nature of all the glasses was confirmed by X-ray diffraction. Discs of each glass were i...
Article
Abrasive slurry jet micro-machining (ASJM) can etch micro-features such as holes and channels in virtually any material. Holes, and to a lesser extent, channels machined in brittle materials using ASJM typically suffer from substantial edge rounding near the opening. This study investigated the erosive mechanism responsible for the rounding in boro...
Article
Full-text available
Abrasive slurry jet micro-machining (ASJM) uses a relatively high-speed jet of fine abrasive slurry to precisely machine controlled-depth micro-features such as channels. Existing surface evolution models, developed for air-driven erosion processes, cannot account for the effect of slurry flow on the channel sidewall erosion that leads to the progr...
Article
Abrasive jet micro-machining (AJM) uses a high-velocity particle jet to erode features in target substrates for a variety of applications, including micro-electro-mechanical and micro-fluidic device fabrication. AJM can result in a dusty environment due primarily to airborne, rebounding abrasive particles that eventually settle. This paper proposes...
Article
Abrasive jet micro-machining (AJM) can be used to machine a wide range of features on the micro-scale. Given a set of process parameters, surface evolution models capable of predicting the shape of straight, constant-depth channels in a wide variety of materials are well-established. This paper presents a novel framework for solving the unaddressed...
Article
Most previous models of solid particle erosion have assumed the abrasives to be rigid, as opposed to deforming, and have largely ignored the effect of particle fracture and fragmentation. However, since particle fracture dissipates kinetic energy and may lead to secondary impact, it can affect the resulting erosion rate and associated mechanisms. I...
Article
Cross sectional shape and centerline waviness along the length of a micro-channel can affect different characteristics of microfluidic flow, including heat transfer, pressure distribution and dissipation, and separation of flow. Current existing technologies that allow such micro-machining have many limitations. The accompanying paper presented inv...
Article
The accompanying paper presented and verified a numerical model to predict the fracture of silicon carbide particles impacting Al 6061-T6 aluminum alloy. In this work, further experiments under conditions that were less likely to cause fragmentation, and for a smaller particle size, confirmed the model׳s predictive capabilities. The model and doubl...
Article
The paper presents a modification to the existing surface evolution models for predicting channel profiles machined using AJM in brittle and ductile materials. Considering the variation in both the local nozzle standoff distance and the divergence angle of each particle trajectory in the jet plume enabled the modified model to address all the short...
Article
This paper presents a new method for applying a uniform thickness bioactive glass coating to a Ti6Al4V substrate and postulates a fracture mechanics testing methodology to quantify the glass/metal adhesion in terms of a measured critical strain energy release rate (GIC). Bi-layer double cantilever beam (DCB) test specimens were developed for this p...
Article
Full-text available
The extreme hardness of sintered ceramics makes it difficult to machine them economically. Abrasive slurry-jet micro-machining (ASJM), in which a target is eroded by the impingement of a micro-jet of water containing fine abrasive particles, is a low-cost alternative for micro-machining of sintered ceramic materials without tool wear and thermal da...
Article
Abrasive slurry jet micro-machining (ASJM) in combination with abrasive air jet micro-machining (AJM) was used to mill micro-pockets in three different ceramic wafers: sintered alumina, aluminum nitride, and zirconium tin titanate. A composite substrate of aluminum nitride with an array of copper-filled through-holes was also machined using a hybri...
Article
In low-pressure abrasive slurry jet micro-machining (ASJM), an aqueous slurry of abrasive particles is used to erode features with relatively high resolution in a variety of brittle and ductile materials. The effects of ASJM operating parameters on the minimum size of micro-channels machined in borosilicate glass and polymethylmethacrylate (PMMA) w...
Article
Bioactive glasses have found applications in diverse fields, including orthopedics and dentistry, where they have been utilized for the fixation of bone and teeth and as scaffolds for drug delivery. The present work outlines the characterization of two novel titanium-containing glass ser