Nanoplatelet Hybrid Research Articles

Engineering the Crystalline Architecture for Enhanced Properties in Fast-Rate Processing of Poly(ether ether ketone) (PEEK) Nanocomposites.

Rapid cooling in fast-rate manufacturing processes such as additive manufacturing and stamp forming limits the development of crystallinity in semicrystalline polymer nanocomposites and, therefore, potential improvements in the mechanical performance. While the nucleation, chain mobility, and crystallization time from rapid cooling are known competing mechanisms in crystallization, herein we elucidate that the crystalline morphology and architecture also play a key role in tuning the mechanical performance. We explore how modifying the spherulite morphology via a cellulose nanocrystal (CNC) and graphene nanoplatelet (GNP) hybrid system in their pristine form can improve or preserve the mechanical properties of poly(ether ether ketone) (PEEK) nanocomposites under two extreme cooling rates (fast -460 °C/min and slow -0.7 °C/min). A scalable manufacturing methodology using water as the medium to disperse the powder system was developed, employing a CNC as a dispersing agent and stabilizer for PEEK and GNP. Despite the expected limited mechanical reinforcement due to thermal degradation, CNCs significantly impacted PEEK's crystalline architecture and mechanical performance, suggesting that surface interactions via lattice matching with PEEK's (200) crystallographic plane play a critical role in engineering the microstructure. In fast cooling, the CNC and CNC:GNP systems reduced the crystallinity, respectively, yet led to minimizing the reduction in the tensile strength and maintaining the tensile modulus at the Neat level in slow cooling. With slow cooling, crystallinity remained relatively unchanged; however, the addition of CNC:GNP improved the strength and modulus by ∼10% and ∼16%, respectively. These findings demonstrate that a hybrid nanomaterial system can tailor PEEK's crystalline microstructure, thus presenting a promising approach for enhancing the mechanical properties of PEEK nanocomposites in fast-rate processes.

Designed and tailor-made double hydrophilic block copolymer-graphene nanoplatelet hybrids for reinforcing epoxy thermosets

Because of their propensity to build micellar nanostructures, amphiphilic block copolymers (ABCs) are an appropriate and unique toughening agent for epoxy systems individually on their own and in grafted form. The presence of epoxiphilic and phobic ends in ABCs is responsible for the self-assembly and the micellar structure. Nanofiller-grafted ABCs can effectively enhance the toughness of epoxy via the synergistic interaction of nanofillers and the ABCs. Even though there is sound literature supporting the effect of ABCs in epoxy, the action of double hydrophilic block copolymers (DHBC) in the epoxy matrix is less handled. Hence, the grafting of nanofillers in DHBCs and their subsequent role in tuning the properties of epoxy is a new concept. Hence this paper tries to bridge the gap via studying the effect of grafted fillers based on DHBCs in epoxy matrix. As a result, the current study focuses on the synthesis of double hydrophilic graphene nanoplatelets (rGO-g-DHBC) via nitrogen oxide-mediated polymerization for epoxy toughening application. The prepared rGO-g-DHBC was effectively utilized for epoxy toughening applications, resulting in a 457% improvement in toughness without compromising its inherent tensile strength. The mechanism behind the improved toughness was elucidated with the help of a scanning electron microscope, and the thermal, and rheological characteristics were studied.

Microstructure, Mechanical, Tribological and Synergistic strengthening mechanisms of nickel/graphene nanoplatelets hybrid reinforced AZ91D magnesium-based matrix composites via spark plasma sintering

AZ91D-Ni-graphene nanoplatelets (GNPs) Mg-based composites were effectively consolidated using spark plasma sintering (SPS). The - reinforcement in the AZ91D Mg alloy varies from 0 wt% to 2 wt%, with Ni constituent fixed at 1.5 wt%. Scanning electron microscope, Transmission electron microscope, X-ray diffraction and Raman spectroscopy were utilised to investigate the morphology of the powder and sintered compact. The synergistic strengthening offered by the inclusion of GNPs comprising grain refinement (ΔσHall−Petch), load transfer from AZ91D-Ni Mg-based alloy matrix to GNPs reinforcement (ΔσLT), dislocations strengthening due to the mismatch in the coefficient of thermal expansion (CTE)(ΔσCTE), modulus mismatch (Δσmm), and strengthening due to Orowan (Δσorowan) was investigated. Experimental results indicate that the addition of GNPs contributes minimally to the densification of the compacts, increasing from 97% to 98.1% with increasing GNPs. However, significant improvements were obtained for other properties investigated, such as a microhardness, which increased from 67.4 to 89.7 H V, nano hardness from 4744.9 to 18,251.3 MPa, an elastic modulus from 84.53 to 243.75 GPa and wear rate from 5.21 × 10−3 to 3.85 × 10−3 mm3/N/m under 10 N load with an increase in GNPs content. This study establishes the capability of GNPs as efficient reinforcement in manufacturing metal matrix composites with enhanced mechanical and tribological properties.

Synergistic effect of carbon nanotube/graphene nanoplatelet hybrids on the elastic and viscoelastic properties of polymer nanocomposites: finite element micromechanical modeling

Synergistic effect of carbon nanotube/graphene nanoplatelet hybrids on the elastic and viscoelastic properties of polymer nanocomposites: finite element micromechanical modeling

Hybrid network formation of silicon carbide and expanded graphene nanoplatelets in epoxy resin for thermal management

AbstractThe current study discusses the incorporation of silicon carbide (SiC) and expanded graphene nanoplatelets (GNP) hybrid filler into epoxy resin to enhance its thermal conductivity, mechanical, and electrical insulation properties. The hybrid filler was incorporated into the epoxy resin by ultrasonic‐assisted blending solution process, and the thermal, electrical, and mechanical properties of the samples were assessed. The results displayed that both SiC and GNP fillers enhance the thermal conductivity of the epoxy resin. Addition of 15.3 wt% SiC/GNP filler (15/0.3) to pure epoxy increased the thermal conductivity coefficient by over 230%. The samples maintained the electrical insulation properties with electrical conductivity (EC) less than 10−9 S/m. Both fillers reduced the breakdown voltage of the samples. Furthermore, strong filler‐matrix adhesion resulted in a significant 414% improvement in Izod impact strength.Highlights Combining SiC and GNP fillers affects the thermal and electrical properties of epoxy. SiC and GNP synergistically improved the thermal diffusivity and conductivity of epoxy. The prepared composites remained in the range of electrical insulation. The impact strength of composites enhanced more than 400% compared to epoxy.

Facile preparation of polymer-based heat dissipation composite coating with enhanced thermal conductivity via optimizing synergistic effect of multi-scale fillers

Aluminum radiator plays a significant role in thermal managing system of passive heat dissipation for high power consuming microelectronic devices. Although inspiring strategies have been proposed to design and prepare polymer-based composites with high thermal conductivity in previous reports, it remains urgent to develop practical techniques for economically fabricating thermally conductive composite coatings in large-scale. To construct efficient heat dissipation film, two-dimensional (2D) graphene nanoplatelets (GNPs)/hexagonal boron nitride nanoplatelets (BNNPs) hybrid fillers are dispersed in polydimethylsiloxane (PDMS) solution with branch-like porous magnéli-phase Ti4O7 microparticles as heat conducting paths, and fabricated via convenient spray-coating. Thermal conductivity of the cured coating presents two-fold increase to 5.339 W m−1 K−1 as compared to the coating without Ti4O7, and a heat dissipation ratio of 13.96 %. Furthermore, the composite coating demonstrates excellent corrosion resistance under neutral salt solution spray. The as-prepared composite coating is of great potential to be applied as protective coating for aluminum radiators.

Synergetic Catalytic and Photocatalytic Performances of Tin-Doped BiFeO3/Graphene Nanoplatelet Hybrids under Dark and Light Conditions.

Because of a rapidly growing need for water, it is essential to find new fast and reliable ways of water purification from organic pollutants. For removing organic azo dyes from water, various catalysts and photocatalysts have been designed to meet crucial water needs. In this study tin (Sn) doped bismuth ferrite (BFO) nanoparticles have been synthesized using the sol-gel technique. Further, BFSO/GNP nanohybrids were synthesized by mixing BFSO nanoparticles with graphene nanoplatelets (GNPs) via a simple and cost effective coprecipitation process. XRD and SEM showed that BFSO/GNP nanohybrids are well grown in crystal structure along with uniform and homogeneous morphology. XPS supported the elemental composition and interface bonding of both materials present inside the nanohybrids. DRS and catalytic activities showed that BFSO/GNP nanohybrids are both dark and light active species for performing dye degradation activities during water purification. The as-synthesized nanohybrids provided efficient dye removal from water even in the absence of light owing to the presence of defects and trap-state carriers (electrons) inside the graphene sheets. The optimized nanohybrid BFSO-15/GNP showed 100% dye removal in 60 min with 90% catalytic activity under dark. The recyclability test showed stable and repeatable performance of BFSO/GNP nanohybrids up to 10 cycles of catalytic activities.

Investigations on Machinability Behavior in Turning of Al7075/Beryl/Graphene Nano Platelets Hybrid Composites with Multilayer Coated Carbide Insert Using Taguchi and Statistical Techniques

This work emphases on characterization and evaluation of machinabity characteristics of a novel hybrid Aluminum Metal Matrix Composite (AMMC) developed through two-step stir-casting method by reinforcing constant amount of Beryl (6%) and varying quantity of Graphene nanoPlatelets - GNPs (0%, 1% and 2%). Morphological analysis result shows the presence of dendritic arms and homogeneous distribution of the Beryl and GNPs in Al7075 matrix. Machinability (turning) characteristics of the developed hybrid composite were studied in detail besides optimizing the machining parameters employing Taguchi technique. The objective was to establish a correlation between cutting parameters such as cutting speed, feed rate and depth of cut with, tool wear, and surface roughness on work piece. In the present study, performance of multilayer hard coatings (TiC/TiCN/Al2O3) on cemented carbide insert for machining of Al7075-Beryl-GNPs. An attempt has been made to analyze the effects of process parameters on machinability aspects using Taguchi technique. Response surface plots are generated for the study of interaction effects of cutting conditions on machinability factors. The correlations were established by multiple linear regression models. The linear regression models were validated using confirmation test.

Cellulose Nano Crystal/Graphene Nano Platelets Hybrid Nanofillers reinforced Polylactic Acid Biocomposites: Mechanical and Morphological Properties

Polylactic acid (PLA) reinforced by hybrid nanofillers biocomposites had been prepared using a melt blending and compression molding technique. The mechanical properties of the PLA biocomposites was studied by incorporating various ratio of cellulose nano crystal (CNC)/graphene nano platelets (GNP) hybrid nanofillers into PLA. The morphological characterization was also carried out using field emission scanning electron microscopy (FESEM) to correlate the fracture surface and nanofiller dispersion with the mechanical properties of the composites. The result show that, at the same CNC/GNP hybrid nanofiller loading (3wt %), the strength properties (tensile and flexural) of PLA biocomposites decreased with increment GNP over CNC ratio. 37.35 MPa and 53.87 MPA; 54.71 MPA and 68.22 MPA, respectively. Meanwhile, PLA biocomposites demonstrated a slight increase in tensile modulus as the GNP ratio is higher than CNC. According to the findings, CNC played an important role in enhancing strength properties while GNP was effective in enhancing the modulus properties. The morphological studies by FESEM prove that, there are relationship between fracture surface and filler dispersion with the mechanical properties of PLA biocomposites.

Microstructure and mechanical properties of bioinspired laminated Al matrix hybrid reinforced with B4C and graphene nanoplatelets

Inspired by the hierarchical structure of the nacre shell and its related multi-scale strengthening and toughening mechanisms, B4C and graphene nanoplatelets (GNPs) hybrid reinforced laminated Al matrix composites were prepared via flake powder metallurgy. Compared with conventional B4C/Al composites with high B4C content, the laminated composites exhibit high relative density, strength and plasticity, and tensile elongation were all above 9.97%. The size of Al flakes obtained by ball milling is the key to realize the laminated structure. The Al flakes with large specific area provided larger contact area with reinforcements leading to low porosity. The large grain size was conducive to the movement of dislocations, while the nanocrystalline grains and interlayer interface hindered the movement of dislocations in the direction perpendicular to the laminates. The laminated structure and combination of hard reinforcement and soft phase Al matrix can achieve a good balance of strength and plasticity of the composites. The high strength reinforcements can effectively prevent crack propagation through the load transfer effect at the interface.

Demystifying the role of graphene nanoplatelets percentage and sonication duration on the mechanical properties of the glass fabric/graphene nanoplatelets hybrid nano‐composite

AbstractIn this study, the effect of sonication time on the mechanical properties of graphene nanoplatelets (GnPs) glass fiber composites were discussed. The Sonication process is one of the best techniques to ensure uniform dispersion of nanofillers into the polymer matrix; otherwise, they form agglomerates of multilayers. To fulfill the massive demand for mass production, ultrasonic bath‐type sonication were deployed. In this study, 0, 1, 2, 3, 4, and 5 wt% of GnPs were added with epoxy at different sonication durations, precisely 0, 20, 40, and 60 min. Other sonication process parameters were kept constant with a sonication frequency of 28 KHz. Bidirectional glass fabric materials was used as reinforcement material in the fabrication of the laminates. In total, 21 laminates were fabricated using the hand lay‐up technique in various amalgamations. The tensile and flexural specimens were cut from the laminates as per the standards to determine their mechanical properties. The scanning electron microscope (SEM) images were used for the structural analysis of the glass fiber reinforced GnPs/epoxy composite. Surface morphology of GnPs becomes more wrinkled, resulting in a stronger graphene/epoxy matrix interface, enhancing the tensile strength and tensile modulus performance of the nano‐composites increases up to 37.12% and 66.30%, the flexural strength and flexural modulus performance of the nano‐composites increases up to 55.74% and 91.23% respectively. Based on the investigations, the influence of the GnPs percentage and the sonication duration for the preparation of the nano‐composites with the help of technique for order of preference by similarity to ideal solution (TOPSIS) optimization technique.

Bio-Based Eucommia ulmoides Gum Composites with High Electromagnetic Interference Shielding Performance.

Herein, high-performance electromagnetic interference (EMI) shielding bio-based composites were prepared by using EUG (Eucommia ulmoides gum) with a crystalline structure as the matrix and carbon nanotube (CNT)/graphene nanoplatelet (GNP) hybrids as the conductive fillers. The morphology of the CNT/GNP hybrids in the CNT/GNP/EUG composites showed the uniform distribution of CNTs and GNPs in EUG, forming a denser filler network, which afforded improved conductivity and EMI shielding effect compared with pure EUG. Accordingly, EMI shielding effectiveness values of the CNT/GNP/EUG composites reached 42 dB in the X-band frequency range, meeting the EMI shielding requirements for commercial products. Electromagnetic waves were mainly absorbed via conduction losses, multiple reflections from interfaces and interfacial dipole relaxation losses. Moreover, the CNT/GNP/EUG composites exhibited attractive mechanical properties and high thermal stability. The combination of excellent EMI shielding performance and attractive mechanical properties render the as-prepared CNT/GNP/EUG composites attractive candidates for various applications.

Enhanced Thermal Conductivity Along with Electrically Insulating of Epoxy Resin with Silicon Carbide\ Expanded Graphene Nanoplatelets Hybrid Filler

Enhanced Thermal Conductivity Along with Electrically Insulating of Epoxy Resin with Silicon Carbide\ Expanded Graphene Nanoplatelets Hybrid Filler

Effect of alumina/graphene hybrid nano reinforcement to the adhesion and mechanical properties of adhesively bonded aluminum alloy with epoxy

In present work, an attempt has been made to investigate the effect of alumina and graphene nanoplatelets (GNP) hybrid nano reinforcement to the wetting behavior and mechanical property of adhesively joint aluminum alloy with epoxy adhesive. Alumina-GNP hybrid nano adhesive at 1.0 wt% concentration with various weight ratio combination (i.e.: 10:0, 7:3, 5:5, 3:7, 0:10) was adopted into two components structural epoxy adhesive to bond 7075-T6 aluminum alloy. When compared to pristine adhesive, hybrid nano adhesive has shown two distinct trends with regard to the spread area behavior: (i) hybrid nano adhesive at 7:3 and 5:5 wt ratio combination exhibits a reduction of spread area up to 71.59 % and 48.07% respectively while (ii) hybrid nano adhesive at 3:7 wt ratio combination has shown an increase of spread up to 31.58%. It is also observed that the incorporation of hybrid nano reinforcement at 7:3 wt ratio combination has demonstrated highest shear strength up to 42.29% as compared to the pristine adhesive counterpart. Moreover, as compared to specimens with single alumina and GNP nano adhesives (i.e.: 10:0 and 0:10 wt ratio), specimens with hybrid nano adhesive at 7:3 wt ratio demonstrates an improved shear strength up to 61.48% and 101.2%, respectively. In current work, it has been observed that regardless of alumina-GNP weight ratio combination, all fractured specimens demonstrated the combination of adhesive and cohesive fractures behavior.

Dual-Encapsulated Highly Conductive and Liquid-Free Phase Change Composites Enabled by Polyurethane/Graphite Nanoplatelets Hybrid Networks for Efficient Energy Storage and Thermal Management.

Phase change materials (PCMs) are regarded as promising candidates for realizing zero-energy thermal management of electronic devices owing to their high thermal storage capacity and stable working temperature. However, PCM-based thermal management always suffers from the long-standing challenges of low thermal conductivity and liquid leakage of PCMs. Herein, a dual-encapsulation strategy to fabricate highly conductive and liquid-free phase change composites (PCCs) for thermal management by constructing a polyurethane/graphite nanoplatelets hybrid networks is reported. The PCM of polyethylene glycol (PEG) is first infiltrated into the cross-linked network of polyurethane (PU) to synthesize hybridized semi-interpenetrated composites (PEG@PU), and then incorporated with reticulated graphite nanoplatelets (RGNPs) via pressure-induced assembly to fabricate highly conductive PCCs (PEG@PU-RGNPs). The hybrid networks enable the PCCs to show excellent mechanical strength, liquid-free phase change, and stable thermal property. Notably, the dual-encapsulated PCCs exhibit high thermal and electrical conductivities up to 27.0 W m-1 K-1 and 51.0 S cm-1 , superior to the state-of-the-art PEG-based PCCs. Furthermore, the PCC-based energy device is demonstrated for efficient battery thermal management toward versatile demands of active preheating at a cold environment and passive cooling at a hot ambient. Overall, this work provides a promising route for fabricating highly conductive and liquid-free PCCs toward thermal management.

Improvement in Tensile Quasi-Static and Fatigue Properties of Carbon Fiber-Reinforced Epoxy Laminates with Matrices Modified by Carbon Nanotubes and Graphene Nanoplatelets Hybrid Nanofillers.

The monotonic and cyclic properties of carbon fiber-reinforced epoxy (CFEP) laminate specimens with matrices modified by multiwalled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) were experimentally studied. The laminate specimens were fabricated by the hand lay-up procedure and six MWCNT:GNP weight ratios, i.e., 0:0, 10:0, 0:10, 5:5, 9:1, and 1:9, were considered to prepare the nanoparticle-modified epoxy resin by using an ultrasonic homogenizer and a planetary centrifugal mixer. Then, these laminate specimens with their matrices modified under various nanofiller ratios were employed to investigate the influence of the number of nanofiller types and hybrid nanofiller ratios on the quasi-static strength, fatigue strength, and mode I fracture toughness. The experimental results show that adding individual types of nanoparticles has a slight influence on the quasi-static and fatigue strengths of the CFEP laminates. However, the remarkable synergistic effect of MWCNTs and GNPs on the studied mechanical properties of the CFEP laminates with matrices reinforced by hybrid nanoparticles has been observed. Examining the evolution of stiffness-based degradation indicates that adding hybrid nanoparticles to the matrix can reduce the degradation effectively. The high experimental data of the mode I fracture toughness of hybrid nano-CFEP laminates demonstrate that embedding hybrid nanoparticles in the matrix is beneficial to the interlaminar properties, further improving the fatigue strength. The pushout mechanism of the MWCNTs and the crack deflection effect of the GNPs suppress the growth and linkage of microcracks in the matrix. Furthermore, the bridging effect of the nanoparticles at the fiber/matrix interface retards the interfacial debonding, further improving the resistance to delamination propagation.

Graphene Nanoplatelets Hybrid Flame Retardant Containing Ionic Liquid and Ammonium Polyphosphate for Modified Bismaleimide Resin: Excellent Flame Retardancy, Thermal Stability, Water Resistance and Unique Dielectric Properties.

To achieve the requirements of modified bismaleimide resin composites in electronic industry and high energy storage devices, flame retardancy, water resistance and dielectric properties must be improved. Hence, a highly efficient multifunctional graphene nanoplatelets hybrid flame retardant is prepared by ionic liquid graphite and ammonium polyphosphate. The preparation processes of the flame retardants are simple, low energy consumption and follow the green chemical concept of 100% utilization of raw materials, compared with chemical stripping. The bismaleimide resin containing 10 wt.% of the flame retardant show good flame retardancy, resulting in the limiting oxygen index increases to above 43%, and the peak heat release rate, total heat release and total smoke release decrease by 41.8%, 47.8% and 52.3%, respectively. After soaking, mass loss percentage of the modified bismaleimide resin only decreases by 0.96%, the dielectric constant of the composite increases by 39.4%, and the dielectric loss decreases with the increase of frequency. The hybrid flame retardants show multifunctional effect in the modified bismaleimide resin, due to the physical barrier, the chemical char-formation, hydrophobicity and strong conductivity attributed to co-work of Graphene nanoplatelets, ammonium polyphosphate and ionic liquid.

Microstructure and properties of poly(butylene terephthalate)/poly(ethylene terephthalate) composites based on carbon nanotubes/graphene nanoplatelets hybrid filler systems

AbstractThis work describes the preparation of poly(butylene terephthalate) (PBT)/poly(ethylene terephthalate) (PET) composites using carbon nanotubes (CNTs)/graphene nanoplatelets (GNPs) hybrid fillers by melt blending process. The effects of CNTs/GNPs hybrid fillers on the thermal conductivity, electrical conductivity, electromagnetic interference shielding effectiveness (EMI SE) and mechanical properties of composites with varying CNTs/GNPs weight ratios were investigated. Scanning electron microscopy showed that the CNTs/GNPs hybrid fillers had better dispersion in PBT/PET matrix, they could effectively cooperate to build filler network structure. The excellent synergistic effects of hybrid fillers could significantly improve the mechanical properties and thermal conductivity. When adding 2 phr CNTs and 8 phr GNPs simultaneously, the thermal conductivity reached 0.84 W m−1 K−1 and Young's modulus was 1.2‐fold compared with PBT/PET blends. In addition, all hybrid composites with higher CNTs/GNPs weight ratios showed better electrical conductivity and EMI SE. The measurement of EMI SE and study of shielding mechanism indicated that absorption loss was the main mechanism for the attenuation of incident electromagnetic waves in hybrid composites over X‐band frequency.

Development and mechanical properties investigation of Cu-MWCNT-graphite nanoplatelets hybrid nanocomposites

In this work, Cu-based MWCNT-xGnP hybrid reinforced nanocomposites were fabricated by spark plasma sintering (SPS) and conventional sintering, and their microstructure and mechanical properties were analyzed using several techniques. As compared to sintered pure Cu samples, a remarkable enhancement in physical and mechanical properties is observed in the developed Cu-based hybrid nanocomposites. Hybrids of multiwalled carbon nanotubes and graphite nanoplatelets (MWCNT-xGnP) containing different ratios of MWCNT and xGnP were used as co-reinforcements to strengthen the Cu matrix. The influence of various MWCNT-xGnP hybrid nanofillers having different weight ratios of MWCNT and xGnP on the microstructure, mechanical properties, and wear behavior of Cu-MWCNT-xGnP nanocomposites have been investigated. The highest relative density, better wear behaviour, and hardness were observed in the case of Cu-2 wt% MWCNT50xGnP50 nanocomposite for both conventionally sintered and SPSed nanocomposites.

Flexible hematite (α-Fe2O3)-graphene nanoplatelet (GnP) hybrids with high thermal conductivity

Hematite (α-Fe2O3) has several attractive properties such as corrosion resistance, catalytic activity, sensing properties, and magnetic features but also a room-temperature stable thermal conductivity of about 16 W/m K. Its use in polymer-matrix composites as a thermal performance enhancer is rather uncommon. In this study, hematite and graphene nanoplatelet (GnP) hybrids in a rubbery latex matrix were prepared and their thermal properties were characterized. The hybrids were mechanically stabilized into freestanding films by hot-pressing them into a porous cellulosic membrane. Optimization of the total filler concentration and the α-Fe2O3/GnP ratio yielded thermal interface material (TIM) films with a thermal conductivity of 8.0 W/mK. Infrared measurements showed that the TIMs significantly improved heat sink cooling and demonstrated rapid heat transfer in a system simulating stacked up electronic packing.