Epoxy flux a low cost high reliability approach for pop assembly-imaps 2011nclee715
Epoxy flux provides a low-cost, high-reliability solution for package-on-package (PoP) assembly that combines soldering and reinforcement into a single-step reflow process. Epoxy flux can be applied by dipping or jetting the packages in the flux prior to assembly. During reflow, the epoxy flux forms solder joints while also curing to reinforce the joints. This eliminates additional underfilling steps and equipment required by other assembly methods. Epoxy flux offers reliability advantages over underfilling such as preventing solder extrusion during rework.
The document summarizes the benefits of the PrīmXComposite concrete system compared to traditional steel bar reinforced concrete. The key points are:
1) The PrīmXComposite system uses steel fibre reinforcement and additives to produce a stronger, more durable concrete that requires no waterproofing and is 30% faster to construct.
2) A case study shows the PrīmXComposite system saved over 16 days of construction time and 146 man-days of labor on a project in Norway compared to traditional reinforcement.
3) The steel fibre reinforcement provides a 50% stronger, more crack-resistant, water-tight and jointless concrete that reduces CO2 emissions by 40% compared to traditional reinforcement.
FRP (fiber reinforced polymers) are a composite material made of fibers encapsulated in a polymer resin matrix. They are used for structural strengthening and repair in construction. FRP provides high tensile strength along the fiber orientation and the resin provides stability, shear strength, and bonding to the substrate. Common fiber types include carbon, glass, and aramid. FRP has advantages over conventional repair methods as it is lightweight, corrosion resistant, and can be applied in occupied spaces. Applications include seismic retrofitting of columns, beams and walls, repairing deteriorated concrete, and strengthening structures like bridges and industrial facilities. FRP installation involves surface preparation, applying primer, saturating fabric with resin, and allowing it to cure. FRP
SUPERCAP FAST is a cement-based, self-leveling underlayment that develops high early strength. It can be applied over concrete, wood, and other rigid flooring substrates 1 day to 5 days before installing flooring. SUPERCAP FAST has advantages like early walkability within 2-4 hours, ability to install flooring after 1 day at 1/4" thickness, and contributing no mold growth. It has high compressive and bond strengths according to tests. The document provides instructions on mixing and applying SUPERCAP FAST over various substrate types.
MBrace is a composite strengthening system that uses carbon fiber sheets bonded to concrete structures with epoxy resin to improve their strength and durability. It has advantages over traditional strengthening techniques like steel plating in that it is lighter, easier to install, and does not change the structure's original alignment. The multi-step MBrace installation process involves surface preparation, application of epoxy primer and saturant, attaching pre-saturated carbon fiber sheets, and optional protective topcoating. MBrace increases structures' load-bearing capacity, ductility, blast resistance, and can be used to retrofit beams, columns, walls, and other elements.
A REVIEW ON STRENGTHENING OF REINFORCED CONCRETE BEAMS USING GLASS FIBER REIN...Ijripublishers Ijri
Worldwide, a great deal of research is currently being conducted concerning the use of fiber reinforced plastic wraps,
laminates and sheets in the repair and strengthening of reinforced concrete members. Fiber-reinforced polymer (FRP)
application is a very effective way to repair and strengthen structures that have become structurally weak over their life
span. FRP repair systems provide an economically viable alternative to traditional repair systems and materials.
Experimental investigations on the flexural and shear behavior of RC beams strengthened using continuous glass fiber
reinforced polymer (GFRP) sheets are carried out. Externally reinforced concrete beams with epoxy-bonded GFRP sheets
were tested to failure using a symmetrical two point concentrated static loading system. Two sets of beams were casted
for this experimental test program. In SET I three beams weak in flexure were casted, out of which one is controlled
beam and other two beams were strengthened using continuous glass fiber reinforced polymer (GFRP) sheets in flexure.
In SET II three beams weak in shear were casted, out of which one is the controlled beam and other two beams were
strengthened using continuous glass fiber reinforced polymer (GFRP) sheets in shear. The strengthening of the beams
is done with different amount and configuration of GFRP sheets.
retrofitting of fire damaged rcc slabs,colums,beamsNayana 54321
This document discusses techniques for retrofitting existing reinforced concrete structures. It introduces various problems that can occur in concrete structures like damage, excessive loading, cracks, and corrosion. Retrofitting aims to restore strength and improve serviceability. Factors influencing the selection of a retrofitting technique include cost, time constraints, and existing structure conditions. Conventional techniques discussed are section enlargement, external plate bonding, external post-tensioning, ferrocement covering, and grouting. An advanced technique of fiber reinforced polymer composites is also introduced, with carbon fiber reinforced polymer being highlighted. CFRP has advantages of high strength, corrosion resistance, and suitability for seismic retrofitting but also has high initial costs.
Epoxy flux a low cost high reliability approach for pop assembly-imaps 2011nclee715
Epoxy flux provides a low-cost, high-reliability solution for package-on-package (PoP) assembly that combines soldering and reinforcement into a single-step reflow process. Epoxy flux can be applied by dipping or jetting the packages in the flux prior to assembly. During reflow, the epoxy flux forms solder joints while also curing to reinforce the joints. This eliminates additional underfilling steps and equipment required by other assembly methods. Epoxy flux offers reliability advantages over underfilling such as preventing solder extrusion during rework.
The document summarizes the benefits of the PrīmXComposite concrete system compared to traditional steel bar reinforced concrete. The key points are:
1) The PrīmXComposite system uses steel fibre reinforcement and additives to produce a stronger, more durable concrete that requires no waterproofing and is 30% faster to construct.
2) A case study shows the PrīmXComposite system saved over 16 days of construction time and 146 man-days of labor on a project in Norway compared to traditional reinforcement.
3) The steel fibre reinforcement provides a 50% stronger, more crack-resistant, water-tight and jointless concrete that reduces CO2 emissions by 40% compared to traditional reinforcement.
FRP (fiber reinforced polymers) are a composite material made of fibers encapsulated in a polymer resin matrix. They are used for structural strengthening and repair in construction. FRP provides high tensile strength along the fiber orientation and the resin provides stability, shear strength, and bonding to the substrate. Common fiber types include carbon, glass, and aramid. FRP has advantages over conventional repair methods as it is lightweight, corrosion resistant, and can be applied in occupied spaces. Applications include seismic retrofitting of columns, beams and walls, repairing deteriorated concrete, and strengthening structures like bridges and industrial facilities. FRP installation involves surface preparation, applying primer, saturating fabric with resin, and allowing it to cure. FRP
SUPERCAP FAST is a cement-based, self-leveling underlayment that develops high early strength. It can be applied over concrete, wood, and other rigid flooring substrates 1 day to 5 days before installing flooring. SUPERCAP FAST has advantages like early walkability within 2-4 hours, ability to install flooring after 1 day at 1/4" thickness, and contributing no mold growth. It has high compressive and bond strengths according to tests. The document provides instructions on mixing and applying SUPERCAP FAST over various substrate types.
MBrace is a composite strengthening system that uses carbon fiber sheets bonded to concrete structures with epoxy resin to improve their strength and durability. It has advantages over traditional strengthening techniques like steel plating in that it is lighter, easier to install, and does not change the structure's original alignment. The multi-step MBrace installation process involves surface preparation, application of epoxy primer and saturant, attaching pre-saturated carbon fiber sheets, and optional protective topcoating. MBrace increases structures' load-bearing capacity, ductility, blast resistance, and can be used to retrofit beams, columns, walls, and other elements.
A REVIEW ON STRENGTHENING OF REINFORCED CONCRETE BEAMS USING GLASS FIBER REIN...Ijripublishers Ijri
Worldwide, a great deal of research is currently being conducted concerning the use of fiber reinforced plastic wraps,
laminates and sheets in the repair and strengthening of reinforced concrete members. Fiber-reinforced polymer (FRP)
application is a very effective way to repair and strengthen structures that have become structurally weak over their life
span. FRP repair systems provide an economically viable alternative to traditional repair systems and materials.
Experimental investigations on the flexural and shear behavior of RC beams strengthened using continuous glass fiber
reinforced polymer (GFRP) sheets are carried out. Externally reinforced concrete beams with epoxy-bonded GFRP sheets
were tested to failure using a symmetrical two point concentrated static loading system. Two sets of beams were casted
for this experimental test program. In SET I three beams weak in flexure were casted, out of which one is controlled
beam and other two beams were strengthened using continuous glass fiber reinforced polymer (GFRP) sheets in flexure.
In SET II three beams weak in shear were casted, out of which one is the controlled beam and other two beams were
strengthened using continuous glass fiber reinforced polymer (GFRP) sheets in shear. The strengthening of the beams
is done with different amount and configuration of GFRP sheets.
retrofitting of fire damaged rcc slabs,colums,beamsNayana 54321
This document discusses techniques for retrofitting existing reinforced concrete structures. It introduces various problems that can occur in concrete structures like damage, excessive loading, cracks, and corrosion. Retrofitting aims to restore strength and improve serviceability. Factors influencing the selection of a retrofitting technique include cost, time constraints, and existing structure conditions. Conventional techniques discussed are section enlargement, external plate bonding, external post-tensioning, ferrocement covering, and grouting. An advanced technique of fiber reinforced polymer composites is also introduced, with carbon fiber reinforced polymer being highlighted. CFRP has advantages of high strength, corrosion resistance, and suitability for seismic retrofitting but also has high initial costs.
The document discusses the potential for basalt rock fibre as a construction material. Basalt rock is widely available around the world including in India. Basalt fibres are non-toxic, non-combustible, and can replace steel at a lower cost. A basalt fibre manufacturing plant is proposed that would use local basalt rock as the raw material and produce basalt reinforcement rods, geotextiles, and continuous fibres for various construction applications. The plant design and basalt fibre production process are described.
Basalt rebar is produced from basalt rock through a process of crushing, melting, drawing into filaments, stretching, cooling, and winding. It offers several advantages over steel rebar such as higher strength, lighter weight, and greater resistance to corrosion. Basalt rebar is used as reinforcement in concrete for applications such as construction, infrastructure, and anywhere highly corrosive conditions are present. It is produced through pultrusion by pulling basalt filaments through a resin bath and heated die to form continuous lengths.
SUPERCAP is a cement-based, self-leveling underlayment used to finish and level concrete floors before installing flooring. It can be applied over concrete, wood, and other rigid subfloors 1/4 to 2 inches thick. SUPERCAP dries quickly and flooring can be installed in as little as 1-3 days. It helps create a smooth, level surface and eliminates the need for power troweling concrete.
In recent years, continuous basalt fibers extruded from naturally fire-resistant basalt are attracted attention as a replacement for asbestos fibers. In the last decade, basalt has emerged as a contender in the fiber reinforcement of composites. Some manufacturer of basalts claims it offers performance similar to S-2 glass fibers at a price point between S-2 glass and E-glass, and may offer manufacturers a less-expensive alternative to carbon fiber. Basalt fibre (BF) is capable to withstand very high temperature and can act as fire blocking element.
Strengthening structures via external bonding of advanced fibre reinforced polymer (FRP) composite is becoming very
popular worldwide during the past decade because it provides a more economical and technically superior alternative
to the traditional techniques in many situations as it offers high strength, low weight, corrosion resistance, high fatigue
resistance, easy and rapid installation and minimal change in structural geometry. Although many in-situ RC beams
are continuous in construction, there has been very limited research work in the area of FRP strengthening of continuous
beams.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
This document summarizes research on using fiber reinforced polymers (FRP) to improve the durability of pervious concrete. Laboratory testing found that higher dosages of longer macro-fibers significantly increased tensile strength, reduced raveling and abrasion, and dramatically improved freeze-thaw durability. Specifically, mixes with 7.5 lbs/yd of 2.25" fibers saw a 44% increase in tensile strength, 15-30% reduction in abrasion losses, and up to 3 times greater freeze-thaw durability compared to plain pervious concrete. The research demonstrates that FRP fibers can enhance the long-term performance of pervious concrete pavements.
Basalt fiber is an effective additive for cement and concrete, improving properties like strength, flexibility, crack resistance, durability, and permeability. When added to concrete, basalt fiber provides three-dimensional reinforcement compared to traditional steel rebar. This improves impact resistance, reduces cracking, and lowers costs. Applications include concrete blocks, floors, infrastructure like roads and tunnels, and military and earthquake-resistant construction.
Repair of damage with composites by Vikas Gupta CDLSIET-Panniwala MotaDr. Vikas Gupta
This document discusses repair of damage to aircraft structures using composites. It describes the advantages of composite repair over metallic repair, including lighter weight, higher strength, and easier field-level repair allowing improved aircraft availability. Various composite repair methods are presented, including injection repair, potting repair, and bonded or bolted patch repairs to restore structural integrity. The equipment and facilities needed for inspection, testing and performing composite repairs in the field or depot are also outlined. The conclusion recommends establishing field-level composite repair facilities to enhance aircraft turnaround rates.
Tabitha G presents on retrofitting existing structures using fibre reinforced polymer (FRP) composites. FRP composites involve reinforcing fibres like carbon, glass or aramid embedded in a polymer resin matrix. Retrofitting techniques involve bonding the FRP composites to the exterior of structures to improve their strength. The process involves surface preparation, applying the FRP laminates, and curing. FRP retrofitting provides benefits like increased strength, corrosion resistance and durability. It can be used to reinforce structures in transportation, construction, marine and other fields, though specialized skills are required and it may not be suitable for all structures.
This document summarizes a study on the tensile properties of different types of fiberglass as reinforcement for low-cost rubber base isolators used in small houses. Testing was conducted on fiberglass samples with and without composite matrices. Fiberglass net had the highest tensile strength compared to woven roving types. Composite samples of net fiberglass with resin showed increased tensile strength after curing at 150°C, making it suitable as reinforcement to increase the stiffness and bonding of rubber layers in base isolators.
FRP composites have advantages over steel for strengthening structures, including higher strength-to-weight ratio, ability to conform to irregular shapes, and corrosion resistance. They are formed using processes like hand lay-up, filament winding, and pultrusion. When bonded to steel, FRP composites can increase strength and stiffness through flexural and fatigue strengthening or prevent local buckling. The bond between FRP and steel is critical and depends on surface treatment and adhesion. FRP composites are an effective technique for strengthening steel structures.
Structural strengthening, restoring and adding capacity is an integral part of today’s concrete repair industry. Structural strengthening may be required for increasing load capacity of beams, columns, walls, and/or slabs, seismic retrofitting, supporting additional live or dead loads not included in original design, to relieve stresses generated by design or construction errors, or to restore original load capacity to damaged structural elements.
EPS Geofoam +40 Years of Experience in Road Construction in NorwayLawrence Le Roux
1. Norway has nearly 40 years of experience using expanded polystyrene (EPS) blocks as a lightweight fill material for road embankments. Monitoring programs show EPS blocks maintain their compressive strength and density over decades with no signs of material deterioration.
2. The first EPS embankment in Norway was constructed in 1972 to reduce settlement of an embankment founded on peat. Subsequent monitoring of embankments up to 24 years old show EPS blocks retain over 90% of their original compressive strength with some blocks increasing in strength over time.
3. A full-scale laboratory test embankment loaded to 52.5 kPa showed deformations only half of calculated values with minimal creep over
CE 72.52 - Lecture 8b - Retrofitting of RC MembersFawad Najam
This document contains a presentation by Dr. Pramin Norachan on fiber reinforced polymer (FRP) systems for strengthening concrete structures. The presentation covers flexural, shear, axial and confinement strengthening using FRP. It discusses various FRP materials, design considerations, and design equations. The key points covered include the materials and properties of FRP, how FRP is used to enhance load capacity, ductility and durability of structures, and design approaches for flexural, shear and confinement strengthening.
The document discusses investigating the mechanical properties and failure analysis of basalt fiber laminate composite for applications in air transportation. The objectives are to fabricate and test basalt fiber reinforced polymer (BFRP) composites to determine their properties. Tests will analyze the unidirectional and bidirectional properties, develop finite element models, determine failure criteria, and tune the composites for aeroelastic applications. Basalt fibers offer properties like corrosion resistance, high strength and modulus, temperature resistance, and are environmentally friendly compared to glass fibers. The aerospace industry is a primary application due to requirements for high strength to weight ratios.
1) Basalt rock fibre is made from extremely fine fibers of basalt, an igneous rock formed from cooled lava. It has properties of high thermal resistance, mechanical strength, chemical resistance, and is environmentally friendly.
2) Basalt fibre has similar or better properties than E-glass fibre such as higher tensile strength, elastic modulus, temperature resistance and lower density.
3) Basalt fibre has various applications in construction, infrastructure, automotive and other industries due to its desirable properties and sustainability.
The document provides an overview of the kinetic metallization process, equipment, and applications. It discusses how kinetic metallization uses fine metal powders and inert gas to consolidate coatings through solid-state bonding without melting, chemicals, or hazardous emissions. The process can be used to apply corrosion resistant, wear resistant, and dimensional restoration coatings to parts made from materials like aluminum, titanium, nickel alloys, and tungsten carbide. Examples are provided of kinetic metallization being used to repair worn hydraulic gears for aircraft, restore damaged hydraulic pads, and repair corrosion on a brake carrier.
This document lists 42 articles, publications, and presentations by Richard R. Lathrop Jr. on topics related to solder paste rheology, metallization, semiconductor packaging, and surface mount technology. The publications date from 1989 to 2012 and include conference presentations at industry events as well as articles in trade publications. Richard Lathrop has extensive experience analyzing and developing solder materials and processes for applications such as wafer bumping and fine pitch surface mount.
C-SI METALLIZATION PASTE RHEOLOGY AND PRINT METROLOGY TECHNIQUES FOR ACHIEVIN...Rick Lathrop
This document discusses techniques for achieving and quantifying improved high aspect ratio finger topography for crystalline silicon metallization pastes. It summarizes that (1) optimizing screen emulsion and wafer surface properties is important for narrow finger widths, (2) advanced rheology measurements of pastes can help predict printability at high speeds and aspect ratios, and (3) specialized 3D metrology is needed to fully characterize the finger geometry and quantify silver usage.
This document summarizes research on improving the efficiency of n-type solar cells beyond 20% efficiency. Key points include: improvements to the existing n-pasha cell process achieved gains of 0.3-0.4% absolute, including more stable processing, reduced front metallization, and an improved back surface field; an efficiency of 20% was obtained using these improvements; further efficiency gains may be possible through an n-type multi-wire technology cell design which achieved a 0.3% absolute gain over n-pasha, reaching 19.7% efficiency.
The document discusses acoustic textiles and summarizes:
1. Nonwovens are preferred for use as acoustic materials due to their porous structure, large surface area, and low production costs.
2. Sound absorption in fibrous materials occurs through frictional losses as sound pressure causes air molecules to oscillate within material interstices, and through momentum and temperature fluctuation losses.
3. A fabric's sound transmission loss increases with frequency, weight per unit area, and air resistance, but decreases with thickness and fiber density. Fabric microstructure also influences transmission loss.
The document discusses the potential for basalt rock fibre as a construction material. Basalt rock is widely available around the world including in India. Basalt fibres are non-toxic, non-combustible, and can replace steel at a lower cost. A basalt fibre manufacturing plant is proposed that would use local basalt rock as the raw material and produce basalt reinforcement rods, geotextiles, and continuous fibres for various construction applications. The plant design and basalt fibre production process are described.
Basalt rebar is produced from basalt rock through a process of crushing, melting, drawing into filaments, stretching, cooling, and winding. It offers several advantages over steel rebar such as higher strength, lighter weight, and greater resistance to corrosion. Basalt rebar is used as reinforcement in concrete for applications such as construction, infrastructure, and anywhere highly corrosive conditions are present. It is produced through pultrusion by pulling basalt filaments through a resin bath and heated die to form continuous lengths.
SUPERCAP is a cement-based, self-leveling underlayment used to finish and level concrete floors before installing flooring. It can be applied over concrete, wood, and other rigid subfloors 1/4 to 2 inches thick. SUPERCAP dries quickly and flooring can be installed in as little as 1-3 days. It helps create a smooth, level surface and eliminates the need for power troweling concrete.
In recent years, continuous basalt fibers extruded from naturally fire-resistant basalt are attracted attention as a replacement for asbestos fibers. In the last decade, basalt has emerged as a contender in the fiber reinforcement of composites. Some manufacturer of basalts claims it offers performance similar to S-2 glass fibers at a price point between S-2 glass and E-glass, and may offer manufacturers a less-expensive alternative to carbon fiber. Basalt fibre (BF) is capable to withstand very high temperature and can act as fire blocking element.
Strengthening structures via external bonding of advanced fibre reinforced polymer (FRP) composite is becoming very
popular worldwide during the past decade because it provides a more economical and technically superior alternative
to the traditional techniques in many situations as it offers high strength, low weight, corrosion resistance, high fatigue
resistance, easy and rapid installation and minimal change in structural geometry. Although many in-situ RC beams
are continuous in construction, there has been very limited research work in the area of FRP strengthening of continuous
beams.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
This document summarizes research on using fiber reinforced polymers (FRP) to improve the durability of pervious concrete. Laboratory testing found that higher dosages of longer macro-fibers significantly increased tensile strength, reduced raveling and abrasion, and dramatically improved freeze-thaw durability. Specifically, mixes with 7.5 lbs/yd of 2.25" fibers saw a 44% increase in tensile strength, 15-30% reduction in abrasion losses, and up to 3 times greater freeze-thaw durability compared to plain pervious concrete. The research demonstrates that FRP fibers can enhance the long-term performance of pervious concrete pavements.
Basalt fiber is an effective additive for cement and concrete, improving properties like strength, flexibility, crack resistance, durability, and permeability. When added to concrete, basalt fiber provides three-dimensional reinforcement compared to traditional steel rebar. This improves impact resistance, reduces cracking, and lowers costs. Applications include concrete blocks, floors, infrastructure like roads and tunnels, and military and earthquake-resistant construction.
Repair of damage with composites by Vikas Gupta CDLSIET-Panniwala MotaDr. Vikas Gupta
This document discusses repair of damage to aircraft structures using composites. It describes the advantages of composite repair over metallic repair, including lighter weight, higher strength, and easier field-level repair allowing improved aircraft availability. Various composite repair methods are presented, including injection repair, potting repair, and bonded or bolted patch repairs to restore structural integrity. The equipment and facilities needed for inspection, testing and performing composite repairs in the field or depot are also outlined. The conclusion recommends establishing field-level composite repair facilities to enhance aircraft turnaround rates.
Tabitha G presents on retrofitting existing structures using fibre reinforced polymer (FRP) composites. FRP composites involve reinforcing fibres like carbon, glass or aramid embedded in a polymer resin matrix. Retrofitting techniques involve bonding the FRP composites to the exterior of structures to improve their strength. The process involves surface preparation, applying the FRP laminates, and curing. FRP retrofitting provides benefits like increased strength, corrosion resistance and durability. It can be used to reinforce structures in transportation, construction, marine and other fields, though specialized skills are required and it may not be suitable for all structures.
This document summarizes a study on the tensile properties of different types of fiberglass as reinforcement for low-cost rubber base isolators used in small houses. Testing was conducted on fiberglass samples with and without composite matrices. Fiberglass net had the highest tensile strength compared to woven roving types. Composite samples of net fiberglass with resin showed increased tensile strength after curing at 150°C, making it suitable as reinforcement to increase the stiffness and bonding of rubber layers in base isolators.
FRP composites have advantages over steel for strengthening structures, including higher strength-to-weight ratio, ability to conform to irregular shapes, and corrosion resistance. They are formed using processes like hand lay-up, filament winding, and pultrusion. When bonded to steel, FRP composites can increase strength and stiffness through flexural and fatigue strengthening or prevent local buckling. The bond between FRP and steel is critical and depends on surface treatment and adhesion. FRP composites are an effective technique for strengthening steel structures.
Structural strengthening, restoring and adding capacity is an integral part of today’s concrete repair industry. Structural strengthening may be required for increasing load capacity of beams, columns, walls, and/or slabs, seismic retrofitting, supporting additional live or dead loads not included in original design, to relieve stresses generated by design or construction errors, or to restore original load capacity to damaged structural elements.
EPS Geofoam +40 Years of Experience in Road Construction in NorwayLawrence Le Roux
1. Norway has nearly 40 years of experience using expanded polystyrene (EPS) blocks as a lightweight fill material for road embankments. Monitoring programs show EPS blocks maintain their compressive strength and density over decades with no signs of material deterioration.
2. The first EPS embankment in Norway was constructed in 1972 to reduce settlement of an embankment founded on peat. Subsequent monitoring of embankments up to 24 years old show EPS blocks retain over 90% of their original compressive strength with some blocks increasing in strength over time.
3. A full-scale laboratory test embankment loaded to 52.5 kPa showed deformations only half of calculated values with minimal creep over
CE 72.52 - Lecture 8b - Retrofitting of RC MembersFawad Najam
This document contains a presentation by Dr. Pramin Norachan on fiber reinforced polymer (FRP) systems for strengthening concrete structures. The presentation covers flexural, shear, axial and confinement strengthening using FRP. It discusses various FRP materials, design considerations, and design equations. The key points covered include the materials and properties of FRP, how FRP is used to enhance load capacity, ductility and durability of structures, and design approaches for flexural, shear and confinement strengthening.
The document discusses investigating the mechanical properties and failure analysis of basalt fiber laminate composite for applications in air transportation. The objectives are to fabricate and test basalt fiber reinforced polymer (BFRP) composites to determine their properties. Tests will analyze the unidirectional and bidirectional properties, develop finite element models, determine failure criteria, and tune the composites for aeroelastic applications. Basalt fibers offer properties like corrosion resistance, high strength and modulus, temperature resistance, and are environmentally friendly compared to glass fibers. The aerospace industry is a primary application due to requirements for high strength to weight ratios.
1) Basalt rock fibre is made from extremely fine fibers of basalt, an igneous rock formed from cooled lava. It has properties of high thermal resistance, mechanical strength, chemical resistance, and is environmentally friendly.
2) Basalt fibre has similar or better properties than E-glass fibre such as higher tensile strength, elastic modulus, temperature resistance and lower density.
3) Basalt fibre has various applications in construction, infrastructure, automotive and other industries due to its desirable properties and sustainability.
The document provides an overview of the kinetic metallization process, equipment, and applications. It discusses how kinetic metallization uses fine metal powders and inert gas to consolidate coatings through solid-state bonding without melting, chemicals, or hazardous emissions. The process can be used to apply corrosion resistant, wear resistant, and dimensional restoration coatings to parts made from materials like aluminum, titanium, nickel alloys, and tungsten carbide. Examples are provided of kinetic metallization being used to repair worn hydraulic gears for aircraft, restore damaged hydraulic pads, and repair corrosion on a brake carrier.
This document lists 42 articles, publications, and presentations by Richard R. Lathrop Jr. on topics related to solder paste rheology, metallization, semiconductor packaging, and surface mount technology. The publications date from 1989 to 2012 and include conference presentations at industry events as well as articles in trade publications. Richard Lathrop has extensive experience analyzing and developing solder materials and processes for applications such as wafer bumping and fine pitch surface mount.
C-SI METALLIZATION PASTE RHEOLOGY AND PRINT METROLOGY TECHNIQUES FOR ACHIEVIN...Rick Lathrop
This document discusses techniques for achieving and quantifying improved high aspect ratio finger topography for crystalline silicon metallization pastes. It summarizes that (1) optimizing screen emulsion and wafer surface properties is important for narrow finger widths, (2) advanced rheology measurements of pastes can help predict printability at high speeds and aspect ratios, and (3) specialized 3D metrology is needed to fully characterize the finger geometry and quantify silver usage.
This document summarizes research on improving the efficiency of n-type solar cells beyond 20% efficiency. Key points include: improvements to the existing n-pasha cell process achieved gains of 0.3-0.4% absolute, including more stable processing, reduced front metallization, and an improved back surface field; an efficiency of 20% was obtained using these improvements; further efficiency gains may be possible through an n-type multi-wire technology cell design which achieved a 0.3% absolute gain over n-pasha, reaching 19.7% efficiency.
The document discusses acoustic textiles and summarizes:
1. Nonwovens are preferred for use as acoustic materials due to their porous structure, large surface area, and low production costs.
2. Sound absorption in fibrous materials occurs through frictional losses as sound pressure causes air molecules to oscillate within material interstices, and through momentum and temperature fluctuation losses.
3. A fabric's sound transmission loss increases with frequency, weight per unit area, and air resistance, but decreases with thickness and fiber density. Fabric microstructure also influences transmission loss.
This document discusses various types of acoustical materials used to control sound, including sound absorbers, diffusers, barriers, and reflectors. It provides details on common sound absorbing materials like acoustical foam panels, fabric-wrapped panels, wall coverings, ceiling tiles, and baffles. These materials use porous materials like foam, fiberglass, and fabrics to absorb sound waves. The document also briefly mentions sound diffusers which scatter sound reflections instead of absorbing them.
NOVEL C-SI METALLIZATION ADHESION TESTING USING MODULE ASSEMBLY MATERIALS
1. NOVEL C-SI METALLIZATION ADHESION TESTING USING MODULE ASSEMBLY MATERIALS
Rick Lathrop and Eduardo Paz
Franklin Advanced Materials
320 Circle of Progress Drive, Suite 102
Pottstown, PA 19464
ABSTRACT: In the crystalline PV module, the integrity of EVA to cell metallization adhesion is imperative for long
term reliability. In traditional module layups the c-Si wafers are encapsulated in EVA polymer for environmental
protection, optical coupling, shock absorption, and dielectric properties. In addition to glass and back sheet adhesion,
the adhesion of the EVA to BSF aluminum and front contact silver metallizations must be robust. With the
introduction of very low bow BSF formulations, the BSF to wafer adhesion may be compromised. Further
complicating this reliability issue is the lack of an industry standard to test BSF-wafer adhesion. This paper describes
and discusses several methods for testing the adhesion of these interfaces using EVA as the adhesive. Measurements
of the EVA to BSF adhesion, which can be significantly reduced by excessive micro-pilling or surface dusting, are
discussed. This paper will detail the test setups for both nail head type tensile testing and peel strength testing using
FPE backsheet for BSF adhesion. Steam aging effects are also explored and reported. Lastly adhesion-bow tradeoffs
are discused and best-of-class bow data presented.
Keywords: Back-Surface-Field, Metallization, c-Si, EVA, Bow
1 INTRODUCTION Failure mechanisms varied from epoxy-BSF surface to
The PV industry lacks established adhesion test methods wafer break. Since the BSF microstructure is fairly
for BSF metallizations, similar to front and back contact porous under normal circumstances as can be seen in
solderability adhesion testing. This presents a challenge Figure 1, the test became questionable as to whether the
for both developers and users of c-Si BSF aluminum heated epoxy was influencing the BSF adhesion by
pastes to perform their own due diligence to ensure that actually strengthening the film during cure. The Quad
the BSF has a robust and reliable bond to the wafer Group Inc. states that their epoxy coating goes from
surface. At the end of the module value chain the bond of enamel-like to water consistency just prior to
both front and back metallizations to the Ethylene Vinyl polymerizing [1]. Further work involved screening
Acetate (EVA) encapsulant is of equal importance. numerous non-heat cure adhesives to replace the epoxy
Since the sintered aluminum BSF surface is unsolderable, and small nail and stud materials. The best alternate
ribbon peel tests used to test both front and back contact adhesive found was the Loctite 454 surface insensitive
silver metallizations are not applicable. For other gel cyanoacrylate. However, there were still drawbacks
unsolderable thick films such as thick film dielectrics and with this method. The first drawback was that this
glazes the Quad Group Inc. devised a tensile pull test adhesive was sensitive to the nail or stud surface
using b-staged epoxy coated studs. The epoxy is coated metallurgy. The Loctite 454 adhesive worked well with
only on the head of a precision nail shaped stud. This zinc plated nails but not plain steel. This limited our
stud is then clamped perpendicular to the surface under choice to a nail type with an irregular shaped head, which
test and cured at 125°C for 10 minutes. When the epoxy produced non-perpendicular bonds and quite a bit of
is cooled, a very high tensile strength bond is formed to variability in the pull data. The second drawback was the
the test surface. For delicate substrates like a silicon question of applicability to steam aged BSF films.
wafer, epoxy coated alumina coupons can be adhered to Cyanoacrylate glues cure with humidity and we saw an
the back of the wafer to strengthen the assembly. The increase in adhesion after steam testing the BSF. The
stud is then pulled until the weakest bond is broken and third drawback was the question of how “real world” this
peak tensile force is recorded. This was the first test was. Although there are tensile forces on the BSF
generation adhesion test developed in-house for BSF. film in the PV module, there are no cyanoacrylates.
2 BSF MEASUREMENT
With the beginning of the in-house development of the
EVA peel test, a way of implementing EVA as the
adhesive in the pull test was the next logical move. EVA
samples were acquired from STR Inc. Solar Division.
Specifically we are using their Photocap fast cure
15295P/UF EVA formulation. EVA is one of the most
popular thermosets for encapsulating the wafer in the
module. EVA is also the “real world” material that needs
to reliably bond with both the BSF aluminum and the
front contact silver.
2.1 EVA Pull Test
The EVA is in sheet form, and a small disc would be the
obvious form factor for the pull test. To achieve this, a
Figure 1: Porous Fired BSF Microstructure
hole punch was utilized to punch a 3mm diameter disc
2. from the EVA film. Figure 2 illustrates this pre-cure the wafer width with the backsheet strip placed directly
assembly. The clip not only provides positive alignment on top of the EVA, justified to one end of the wafer. A
of the nail and the EVA disc but also puts pressure on the semi-rigid piece of Teflon sheet is placed on top of the
EVA, similar to a laminator. The assembly is placed in an backsheet followed by a section of stainless steel U-
oven and allowed to reach 150°C for 10 minutes. After channel to provide compression during the cure, similar
cooling, the clip is removed and the coupon is clamped to to a laminator. The tray with this assembly is placed in a
box oven and allowed to reach 150°C for 10 minutes to
cure the EVA. The actual time that this assembly is in the
oven is about 30 minutes. After cooling, the wafer with
the laminated EVA-backsheet strip is placed in the peel
test fixture. This fixture is mounted on two linear
bearings to ensure a true 180 peel test. The backsheet is
peeled at 200mm/min until the end of travel on the test
EVA stand is achieved as can be seen in Figure 4. The entire
peel test is recorded and plotted (force vs position). The
failure mechanisms are recorded.
Figure 2: Nail-EVA-Wafer Coupon Assembly
the upper surface of a pair of linear bearings mounted to
the test stand stage. These bearings ensure a pure tensile
pull with no shear components to the test. A flat washer
with a 4mm center hole is placed on the upper surface to
limit the pull forces to the immediate area surrounding
the nail head as shown in Figure 3. Use of this washer
elliminates the need to strenghten the wafer prior to test.
The pull test is performed at a pull rate of 5mm/min until
a peak force is recorded. Failure mechanisms are also
noted. This method has been used to test front contact
and both pre and post steam aged BSF adhesion. Backsheet
Wafer
Figure 4: 180 Degree EVA Peel Test
2.3 BSF Tape Peel Test
The third BSF adhesion test is a scotch tape test that is
performed similarly to the EVA peel test. Industrial clear
3M adhesive tape (#600) is cut to about 2 1/2 times the
wafer width to enable a 180 degree peel. This test
Figure 3: EVA Pull Test Fixturing
originated from the printed circuit board industry and can
show gross failures of the sintered aluminum BSF
2.2 EVA BSF Peel Test coating. The tape width is 0.75”. The entire length of the
The EVA peel test has been fashioned after our in-house wafer is covered with this tape. The tape is pressed on
front and back contact silver solder adhesion peel test [2]. with finger pressure, folded back on itself, placed in the
Since the cured EVA is highly elastic, it needed to be peel test fixture and peeled at 180 degrees at a rate of
strengthened with a more rigid material. To accomplish 500m/min until the end of travel on the test stand is
this, Dun-Solar FPE backsheet was acquired from the achieved. The section of the tape that was peeled from
Dunmore Corporation. A 4mm wide strip of backsheet the BSF surface is placed on white paper and examined
and EVA are cut with the outer Fluoro layer of the for any lifted aluminum.
backsheet marked to indicate that the PE inner layer on The tape test can be considered, for the most part,
the other side needs to be mated with the EVA prior to redundant to the EVA peel test but is prefered by some to
cure. The length of the backsheet strip is about 2 1/2 be a simple go no-go test. The EVA peel test is a much
times the wafer width to enable a 180 degree peel, while more severe adhesion test in that peel force per mm has
the EVA strip length is cut about 1cm short of the wafer been found to be more than 20 times that of the tape test.
width to avoid any EVA flowing onto the tray during the
cure process. The wafer under test is placed on a metal 2.4 Bow Measurement
tray with the BSF side up; the EVA strip is centered on The aluminum BSF backplane dominates the finished cell
3. bow behavior. This is largely due to the glass frit binder
used in BSF pastes [3]. This glass frit is necessary to An interesting comparison can be seen in Figure 6. This
provide adhesion to the wafer surface. The thinner the comparison shows a slightly higher median adhesion of
wafer the more pronounced the bow behavior is. The the LunAl 988-F BSF paste over the bare wafer back
nominal wafer thickness is 180 microns. Severe bow surface and a significantly higher median adhesion of a
causes handling issues at both cell manufacture and large pad of front contact formulation SunAg 898-L2
ribbon attachment during module assembly. over the bare wafer front surface. The bare wafer front
The in-house procedure developed for measuring bow is surface adhesion is higher than the back presumably due
a relatively simple non-contact method. First, a finished to texturing of the front surface. When testing a 1.8mm
cell is placed with the front contact side up on a granite wide front contact buss bar, the adhesion is similar to the
slab and a laser triangulation sensor is zeroed to the bare wafer surface. This is likely due to the overhang of
center of the relaxed cell. Second a large “C” washer is the nail head and EVA onto the bare wafer. Equal or
placed around the center to compress the bow as in better EVA adhesion to the wafer surfaces of these
Figure 5. The weight of this washer is 105 grams. The metallization films is considered excellent.
distance reading on the sensor is the bow in millimeters.
3.2 EVA and Tape Peel Results
The plot below (Figure 7) shows a consistent peel in the
25 to 35 Newton range with no removed BSF in the
picture overlay. The strip of backsheet is approximately
4mm wide. The tape test (Figure 8) shows a very
consistent peel in the 10 Newton range. The tape is
19mm wide.
Laser Spot
“C” Washer
Figure 5: Cell Bow Measurements
3 RESULTS
The results reported in this section are in box plot form Figure 7: BSF EVA Peel Test
for pull tests and force-displacement curves for peel tests.
BSF data is from the LunAl aluminum paste series and
front contact data from the SunAg paste series. Wafers
were 156mm multicrystalline with a nominal thickness of
180 microns. Peak firing temperatures were in the 775°C-
790°C range.
3.1 EVA Pull Results
Figure 8: BSF Tape Peel Test
3.3 Steam Aging Effects
Although cells are encapsulated with EVA, moisture
intrusion into the module and its negative effects on
reliability are of concern. The porous nature of the BSF
microstructure, and thus the potential vulnerability to
moisture, has given rise to various methods of accelerating
the long-term effects of moisture. Typically the accelerant
is temperature in the form of damp heat [4], steam or
boiling DI water. As mentioned earlier, the cyanoacrylate
adhesive was discounted for steam aged BSF adhesion
testing due to its curing method (humidity) and the trend of
increasing BSF adhesion after steam testing. Figure 9
shows that the EVA adhesion testing also increases in both
steam and boiling DI water. The strengthening of the BSF
Figure 6: EVA Pull Adhesion film seems to be independent of both the adhesive used and
the accelerant method.
4. small sections of BSF ripped off the wafer when peel
forces exceeded the materials adhesion to the wafer.
Once a section was removed, peel forces were relieved
then would build up to a failure level and a new section
would be removed. This cycle continued throughout the
test as can be seen in Figure 11. The glass containing
paste retained all of the material on the wafer as can be
seen at the bottom in Figure 12.
Figure 11: BSF Adhesion Failure
Figure 9: Effects of Moisture on BSF Adhesion
4 BALANCING BOW AND ADHESION
Common to all thick film formulations is balancing key
properties to optimize the overall performance of the
product. Key properties of BSF aluminum paste are wafer
bow and adhesion. Figure 10 illustrates this point well. Figure 12: Glass-Free Formula on Top
Glass A is driving adhesion up at the expense of bow.
Glass B is driving bow down at the expense of adhesion.
A blend of these glasses provides optimization of both of 4.2 Low Bow Formulation
these key properties. By moving to an optimized blend of glass from a single
glass formula, and careful selection of the aluminum
source and powder specifications the current generation
II BSF metallization paste (LunAl 988-F) demonstrates
best-in-class low bow. Figure 13 shows this performance
against generation I and a leading competitor at three
different firing temperatures.
Figure 10: BSF Glass Formulation Optimization
4.1 Enough Adhesion
Since there is a tradeoff between adhesion and bow and
there are no industry standards for adhesion, how much
adhesion is enough?
Two experimental BSF pastes were created, one with no
glass and one with glass in the normal range of 2-5%.
The tape test was performed with little contrast between
the two formulas. The peeled tape was slightly darker
with the glass-free formula but too similar to the glass
containing formula to be photographed for this paper. Figure 13: Best-in-Class Bow
The EVA peel test, however, showed a significant
contrast in failure modes. With the glass-free material,
5. 6 CONCLUSIONS
• EVA is an ideal real world adhesive for both
tensile pull and peel testing. For peel testing it
must be strengthened with backsheet.
• Steam or boiling water conditioning increases
BSF adhesion using either cyanoacrylate or
EVA adhesives.
• Glass frit is required to give adequate adhesion
but can have a negative impact on wafer bow.
• Careful selection and characterization of the
glass or glass blends can optimize bow and
adhesion BSF properties.
• Best-in-class sub half millimeter total bow can
be achieved on 125 monocrystalline wafers
with diligent formulation and material
selection.
7 REFERENCES
[1] Quad Group Inc. website, “Stud Pull Tests”,
http://www.quadgroupinc.com/studpull.html
[2] Lathrop et al: “Novel Approaches to Benchmarking
Solar Cell Tabbing Solderability”, Proceedings 26th
EU PVSEC, 2011 Hamburg
[3] Carroll et al: “Advances in PV Metallisation
Technology”, Proceedings 20th EU PVSEC, 2005
Barcelona
[4] Ketola et al: “Degradation Mechanism Investigation
of Extended Damp Heat Aged PV Modules”,
Proceedings 26th EU PVSEC, 2011 Hamburg