Thermal Modification by High Speed In Situ Mixing for Nanoparticles TiO2 and SDS Surfactant to Paraffin Based PCM Nano Enhanced Composite

2021 ◽  
Vol 1028 ◽  
pp. 240-248
Author(s):  
Edwin Arfiansyah ◽  
A.L. Juwono
Keyword(s):  
High Speed ◽  
Sodium Dodecyl ◽  
Material System ◽  
Mechanical Mixing ◽  
Scanning Calorimetry ◽  
Practical Applications ◽  
Wide Range ◽  
Nanocomposite Pcm ◽  
Xrd Patterns

The use of liquid-solid type phase change material (PCM) is increasing due to the importance of having a good storage for latent heat, which can be attributed to its wide range of application, such as electronics, buildings, textiles, and the automotive sector. This study employed an experimental procedure through in situ mechanical mixing of paraffin-based PCM and 4Wt% Titanium dioxide (TiO2) rutile to form nanocomposite PCM with high-speed agitation (900 rpm at 90°C for 60 minutes) and mixed with Sodium Dodecyl Sulphate (SDS) as the dispersant. It was conducted by applying premixing of polar solution (distilled H20 + 4Wt% SDS dispersant) to the aforementioned non-polar paraffin-based solution (paraffin wax + 4Wt% TiO2) in a 1:4 ratio, then cooled naturally. The Fourier Transient Infrared (FTIR) spectrum and the X-Ray Diffraction (XRD) pattern indicated a characteristic typical of composite systems, in which. there is no new material system composed. The typical wavenumbers of composite PW+TiO2 (2918 cm-1, 2851cm-1, 1471 cm-1, 720cm-1 and 469 cm-1) were also seen in the FTIR, while high intensity peaks 2θ = 21.4°, 23.8 and low intensity peaks 27.4°, 36.074°, XRD patterns could be tied to monoclinic paraffin crystal with the typical plane diffractions of (110) and (200) and TiO2. The thermal properties of the composite were measured using Differential Scanning Calorimetry. The findings showed that the paraffin based PCM comprised a higher thermal storage capacity of 144.3 J/g compared to its common 104.5 J/g typology. Scanning Electron Microscope observation showed a better dispersion of TiO2 clusters (smooth, spherical, and spreading). The results ultimately showed that optimizing the agitation speed at the prompt temperature contributes to the increase of the crystallite size and the capacity to isolate the temperature of nanoparticles, which may elicit a growing interest for more practical applications of the nanocomposites PCM.

scholarly journals Influence of Gemini Surfactants on Biochemical Profile and Ultrastructure of Aspergillus brasiliensis

2019 ◽  
Vol 9 (2) ◽  
pp. 245 ◽  
Author(s):  
Anna Koziróg ◽  
Anna Otlewska ◽  
Magdalena Gapińska ◽  
Sylwia Michlewska
Keyword(s):  
Gemini Surfactants ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Control Sample ◽  
Extracellular Proteins ◽  
Practical Applications ◽  
Aspergillus Brasiliensis ◽  
Cationic Gemini Surfactants ◽  
Wide Range ◽  
Cationic Compounds

In this study, we investigated the activities of hexamethylene-1,6-bis-(N,N-dimethyl-N-dodecylammonium bromide) (C6), pentamethylene-1,5-bis-(N,N-dimethyl-N-dodecylammonium bromide) (C5), and their two neutral analogues: hexamethylene-1,6-bis-(N-methyl-N-dodecylamine) (A6) and pentamethylene-1,5-bis-(N-methyl-N-dodecylamine) (A5) at concentrations of ½ MIC, MIC, and 2 MIC (minimal inhibitory concentration) against hyphal forms of Aspergillus brasiliensis ATCC 16404. Enzymatic profiles were determined using the API-ZYM system. Extracellular proteins were extracted from the mycelia and analyzed using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The ultrastructure was evaluated using a transmission electron microscope (TEM). Both groups of surfactants caused changes in the enzyme profiles. Larger changes in the number and concentration of enzymes were noted after the action of non-ionic gemini surfactants, which may have been due to the 100× higher concentration of neutral compounds. Larger differences between the protein profiles of the control sample and the biocide samples were observed following the use of cationic compounds. On the basis of TEM analyses, we found that, with increasing concentrations of compound C6, the mycelium cells gradually degraded. After treatment at 2 MIC, only membranous structures, multiform bodies, and dense electron pellets remained. Based on these results, we concluded that cationic gemini surfactants, in comparison with their non-ionic analogues, could have a wide range of practical applications as active compounds.

scholarly journals Directional soliton and breather beams

2019 ◽  
Vol 116 (20) ◽  
pp. 9759-9763 ◽  
Author(s):  
Amin Chabchoub ◽  
Kento Mozumi ◽  
Norbert Hoffmann ◽  
Alexander V. Babanin ◽  
Alessandro Toffoli ◽  
...  
Keyword(s):  
High Speed ◽  
Evolution Equations ◽  
Rogue Waves ◽  
Fundamental Solutions ◽  
Dispersive Media ◽  
Unstable Wave ◽  
Practical Applications ◽  
Wide Range ◽  
Plasma Hydrodynamics ◽  
Crest Length

Solitons and breathers are nonlinear modes that exist in a wide range of physical systems. They are fundamental solutions of a number of nonlinear wave evolution equations, including the unidirectional nonlinear Schrödinger equation (NLSE). We report the observation of slanted solitons and breathers propagating at an angle with respect to the direction of propagation of the wave field. As the coherence is diagonal, the scale in the crest direction becomes finite; consequently, beam dynamics form. Spatiotemporal measurements of the water surface elevation are obtained by stereo-reconstructing the positions of the floating markers placed on a regular lattice and recorded with two synchronized high-speed cameras. Experimental results, based on the predictions obtained from the (2D + 1) hyperbolic NLSE equation, are in excellent agreement with the theory. Our study proves the existence of such unique and coherent wave packets and has serious implications for practical applications in optical sciences and physical oceanography. Moreover, unstable wave fields in this geometry may explain the formation of directional large-amplitude rogue waves with a finite crest length within a wide range of nonlinear dispersive media, such as Bose–Einstein condensates, solids, plasma, hydrodynamics, and optics.

Structure and Properties of Hybrid Polyurethane Composites with Carboxyalumoxanes

2008 ◽  
Vol 587-588 ◽  
pp. 212-216 ◽  
Author(s):  
Magdalena Jurczyk-Kowalska ◽  
Joanna Ryszkowska
Keyword(s):  
In Situ Polymerization ◽  
Structure And Properties ◽  
Mechanical Mixing ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Matrix ◽  
Polyurethane Composites ◽  
Polyurethane Matrix

Carboxyalumoxanes have been incorporated into a polyurethane matrix by in situ polymerization. The filler was dispersed in the polyurethane matrix by either both ultrasonic and mechanical mixing or by mechanical mixing alone. The physico-mechanical properties of the composites have been characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Using ultrasound improves the degree of dispersion of the fillers in the matrix, but it also causes changes in the structure of the polyurethane matrix.

scholarly journals Cavitation and bubble dynamics: the Kelvin impulse and its applications

2015 ◽  
Vol 5 (5) ◽  
pp. 20150017 ◽  
Author(s):  
John R. Blake ◽  
David M. Leppinen ◽  
Qianxi Wang
Keyword(s):  
Cavitation Bubble ◽  
High Speed ◽  
Bubble Dynamics ◽  
Clinical Medicine ◽  
Bubble Collapse ◽  
Rigid Boundary ◽  
Design Problems ◽  
Practical Applications ◽  
Wide Range ◽  
Naval Engineering

Cavitation and bubble dynamics have a wide range of practical applications in a range of disciplines, including hydraulic, mechanical and naval engineering, oil exploration, clinical medicine and sonochemistry. However, this paper focuses on how a fundamental concept, the Kelvin impulse, can provide practical insights into engineering and industrial design problems. The pathway is provided through physical insight, idealized experiments and enhancing the accuracy and interpretation of the computation. In 1966, Benjamin and Ellis made a number of important statements relating to the use of the Kelvin impulse in cavitation and bubble dynamics, one of these being ‘One should always reason in terms of the Kelvin impulse, not in terms of the fluid momentum…’. We revisit part of this paper, developing the Kelvin impulse from first principles, using it, not only as a check on advanced computations (for which it was first used!), but also to provide greater physical insights into cavitation bubble dynamics near boundaries (rigid, potential free surface, two-fluid interface, flexible surface and axisymmetric stagnation point flow) and to provide predictions on different types of bubble collapse behaviour, later compared against experiments. The paper concludes with two recent studies involving (i) the direction of the jet formation in a cavitation bubble close to a rigid boundary in the presence of high-intensity ultrasound propagated parallel to the surface and (ii) the study of a ‘paradigm bubble model’ for the collapse of a translating spherical bubble, sometimes leading to a constant velocity high-speed jet, known as the Longuet-Higgins jet.

scholarly journals An Instrumented High-Speed Rotor With Embedded Telemetry for the Continuous Spatial Pressure Profile Measurement in Gas Lubricated Bearings: A Proof of Concept

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Karim Shalash ◽  
Jürg Schiffmann
Keyword(s):  
System Identification ◽  
High Speed ◽  
Pressure Field ◽  
Pressure Profile ◽  
Journal Bearings ◽  
Profile Measurement ◽  
Pressure Measurements ◽  
Wide Range ◽  
Static Conditions

Abstract Pressure is the constitutive quantity governing the flow field in gas lubricated bearings. Knowledge of the pressure is of principal importance in the fundamental understanding of such bearings as well as for the validation of their models. Pressure measurements can be done from the bearing side using pressure taps, yet, several details will not be captured. In order to acquire a continuous scan of the pressure field inside the bearing, it is necessary to measure from the rotor side. This paper presents an instrumented measurement high-speed rotor with embedded pressure probes and a wireless telemetry that is capable of the continuous pressure field measurement within the gas film of journal bearings. The rotor was tested on externally pressurized gas journal bearings (EPGJBs) (D = 40 mm and L/D = 1), and pressure profile measurements were acquired up to 37.5 krpm (DN 1.5 M). Measurements at discrete points using pressure taps inside the test bearing were also performed for comparison. The measurements from both sides (bearing and rotor) were in good agreement at quasi-static conditions. At higher operational speeds, it was necessary to perform an in situ system identification and calibration for the embedded pressure probes using the bearing side measurements as a reference. The in situ system identification technique was successful to reconstruct the attenuated pressure signals for a wide range of supply pressures (amplitudes) and rotor speeds (excitation frequencies). The instrumented rotor was proven qualified to perform time-resolved pressure measurements within the gas film of journal bearings up to 37.5 krpm.

Characterization of Polystyrene (PS)/Organomodified Layered Double Hydroxide (OLDH) Nanocomposites Prepared by In Situ Polymerization

2011 ◽  
Vol 410 ◽  
pp. 164-167 ◽  
Author(s):  
Balakrushna Sahu ◽  
G. Pugazhenthi
Keyword(s):  
In Situ Polymerization ◽  
Sodium Dodecyl ◽  
Decomposition Temperature ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Stretching Vibration ◽  
Xrd Patterns ◽  
Co Precipitation ◽  
Double Hydroxide

PS/LDH nanocomposites were synthesized via in-situ polymerization technique using styrene monomer with toluene as a solvent. A series of LDHs (Mg-Al, Co-Al, Ni-Al, Cu-Al, Cu-Fe and Cu-Cr LDHs) was first prepared from their nitrate salts by co-precipitation method. The above prepared, pristine LDHs were organically modified using sodium dodecyl sulfate (SDS) to obtain organomodified LDHs (OLDH). Then, PS nanocomposites containing 5 wt.% OLDHs were prepared by in-situ polymerization method. The structural and thermal properties of LDHs and corresponding nanocomposites were characterized by X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA). The absence of OLDH peak (003) in the XRD patterns of PS/OLDH nanocomposite confirms the formation of exfoliated nanocomposites. The presence of sulfate groups in the modified LDHs is confirmed by FTIR analysis. The appearance of new peaks in the FTIR spectra in the region of 3400-3500 cm-1, 1670-1680 cm-1and 1200-1260 cm-1for O-H stretching, H-O-H vibration and stretching vibration of sulfate, respectively indicate the existence of LDHs in the PS/OLDH nanocomposites. The entire exfoliated PS/OLDH nanocomposites exhibit enhanced thermal stability relative to the pure PS. When 50% weight loss is selected as point of comparison, the decomposition temperature of nanocomposites is about 3-5oC higher than that of pure PS.

Abrasive Waterjet Profile Cutting of Thick Titanium/Graphite Fiber Metal Laminate

2016 ◽  
Author(s):  
Rishi Pahuja ◽  
M. Ramulu ◽  
M. Hashish
Keyword(s):  
Composite Laminates ◽  
High Speed ◽  
Water Pressure ◽  
Load Ratio ◽  
Traverse Speed ◽  
Abrasive Waterjet ◽  
Material System ◽  
Machined Surface ◽  
Wide Range ◽  
Fiber Metal

Fiber Metal Laminates (FML) are one of the most advanced engineered materials used in aerospace industry. The combination of metallic sheets interspersed in composite laminates in one hybrid material system provides higher impact and corrosion resistance when compared with their monolithic counterparts. However, due to the difference in machining responses for different material phases, conventional machining often induce damages and defects, affecting the cost and structural performance of the part. This research study investigates the machinability of thermoplastic Titanium Graphite (TiGr) FML. The feasibility and machinability of contouring thick (7.6 mm–10.5 mm) TiGr through Abrasive Waterjet (AWJ) process was studied in terms of machined kerf characteristics — taper ratio and surface quality. The effect of a wide range of process parameters was investigated such as geometric variables (mixing tube aspect ratio and orifice bore size), kinetic variables (water pressure, jet traverse speed) and abrasive load ratio on the machining quality. Predictive mathematical regression models were developed through Analysis of Variance (ANOVA) in order to optimize the process. Alongside, machined surface was examined to inspect the topological characteristics, material removal mechanism, and machining induced damage (micro-defects) and distortion through Surface Profilometry, Scanning electron and optical microscopy. A comparison was drawn between conventional and AWJ trimming of TiGr to demonstrate the superiority and high speed machining of AWJ with less damage.

Tunneling MOSFETs Based on III-V Staggered Heterojunctions

2010 ◽  
Vol 1252 ◽  
Author(s):  
Peter Asbeck ◽  
Lingquan Wang ◽  
Siyuan Gu ◽  
Yuan Taur ◽  
Edward Yu
Keyword(s):  
High Speed ◽  
Supply Voltage ◽  
Thermionic Emission ◽  
Interface State ◽  
State Density ◽  
Material System ◽  
Power Supply Voltage ◽  
Novel Device ◽  
Wide Range ◽  
Voltage Swing

AbstractA critical problem for the progression of CMOS electronics to the nanoscale is the reduction of power density, while at the same time preserving high speed performance. One of the most promising approaches is to aggressively reduce the power supply voltage by using a novel device, the tunneling MOSFET (TMOSFET), which is a MOSFET that operates by tunnel-injection of carriers from source to channel, rather than by conventional thermionic emission. TMOSFETs benefit from steep (sub-60mV/dec) gate turn-on characteristics. In this paper we show that TMOSFET designs based on staggered heterojunctions are particularly promising, since the choice of materials for the injector (source) and channel allows optimization of the tunneling probability at the heterojunction. Analysis and simulation of MOSFETs based on the GaAlSb / InGaAs material system are presented. The energy offset between the valence band of the injector and the conduction band of the channel at the heterojunction can be tailored over a wide range, from negative values (“offset” band lineup) to values in excess of 1eV. We find by simulation that for optimal values of effective heterojunction bandgap near 0.2eV, the resulting MOSFETs are capable of delivering >0.5mA/mm while maintaining on-off ratio greater than four orders of magnitude over voltage swing of 0.3V. We also discuss a variety of materials-related challenges that must be overcome to realize the predicted performance. Among these are the need to provide near ideal heterojunctions between the materials, employ high K dielectrics with very low interface state density, and achieve good alignment between the gate and the heterojunction. Different configurations for the tunneling MOSFETs are presented.

scholarly journals Microstructure and Thermal Properties of Polypropylene/Clay Nanocomposites with TiCl4/MgCl2/Clay Compound Catalyst

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Limei Wang ◽  
Aihua He
Keyword(s):  
Thermal Properties ◽  
Clay Nanocomposites ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Melt Temperature ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Clay Layers ◽  
Thermal Stability Of

Polypropylene (PP)/clay nanocomposites were synthesized by in situ intercalative polymerization with TiCl4/MgCl2/clay compound catalyst. Microstructure and thermal properties of PP/clay nanocomposites were studied in detail. Fourier transform infrared (FTIR) spectra indicated that PP/clay nanocomposites were successfully prepared. Both wide-angle X-ray diffraction (XRD) and transmission electron microscopy (TEM) examination proved that clay layers are homogeneously distributed in PP matrix. XRD patterns also showed that theαphase was the dominate crystal phase of PP in the nanocomposites. Thermogravimetric analysis (TGA) examinations confirmed that thermal stability of PP/clay nanocomposites was markedly superior to pure PP. Differential scanning calorimetry (DSC) scans showed that the melt temperature and the crystallinity of nanocomposites were slightly lower than those of pure PP due to crystals imperfections.

Preparation and Characterization of Hybrid Organic/Inorganic Nanocomposites by In Situ Miniemulsion Polymerization

2006 ◽  
Vol 514-516 ◽  
pp. 1201-1205 ◽  
Author(s):  
M. Lehocký ◽  
A. Catarina Esteves ◽  
Ana M. Barros-Timmons ◽  
João A.P. Coutinho
Keyword(s):  
Sodium Dodecyl Sulfate ◽  
Coupling Agent ◽  
Sodium Dodecyl ◽  
Miniemulsion Polymerization ◽  
Monomer Conversion ◽  
Silica Particles ◽  
Wide Range ◽  
Inorganic Nanocomposites

SiO2/polystyrene nanocomposite particles were synthesized via miniemulsion polymerization using sodium dodecyl sulfate (SDS) as surfactant and hexadecane as hydrophobe in the presence of silica particles coated with methacryloxy(propyl)trimethoxysilane (MPS) surface coupling agent. The silica particles were individually coated with polymer yielding a very homogenous nanocomposite latex which was very stable in a wide range of ionic strengths. Monomer conversion was reasonably high and fast.

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