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Oil palm empty fruit bunches (OPEFB) are abundant lignocellulosic waste materials from palm oil mills in Malaysia. In this study, we aimed to fabricate natural rubber/cellulose nanofiber (NR/CNF) nanocomposite films from OPEFB and to examine their morphological, thermal, and mechanical properties. Formation of NR/CNF composite was confirmed by the presence of functional groups obtained from the FTIR spectrum. The NR formulations were modified with 0.01, 0.10, 0.50, 1.00 phr of CNFs. Our results showed that the specimen with 0.50 phr of CNFs exhibited significant rise ~ 44% in tensile strength whereas further addition with 1.00 phr resulted in more brittle behavior. Incorporation of CNF had negligible effects on the thermal stability of the NR/CNF nanocomposites. The CNF-filled rubber composites showed a rough surface morphology under observation by SEM. We believe that this work will provide a new idea to produce high-performance rubber composite films for glove manufacturing applications.

This study investigated the emulsifying properties of a protein–polysaccharide hybrid nanoconjugate system comprising cellulose nanocrystals (CNC, 1% w/v) and soy protein isolate at various concentrations (SPI, 1–3% w/v). The average particle size of the nanoconjugate increased, and the zeta potential decreased when 3% (w/v) of SPI was used. The contact angle and thermal stability of CNC improved with the conjugation of SPI. Upon Pickering emulsification, 0.5% (w/v) of CNC–SPI nanoconjugate as particle stabilizer was sufficient to obtain stable emulsions. The CNC–SPI1 formulation (CNC to SPI, 1:1) provided the emulsion with the smallest droplet size and higher emulsifying activity. Intriguingly, ultrasound (US) pre-treatment on nanoconjugates before emulsification significantly reduced the size of the emulsion. The rheological assessment demonstrated that the CNC–SPI-stabilized emulsions exhibit shear thinning behavior at a lower shear rate and shear thickening behavior at a higher shear rate, indicating the interruption of existing attractive interactions between the CNC particles. All emulsions exhibited higher elastic modulus (G′) than viscous modulus (G″), suggesting high viscoelastic properties of the emulsions. This study demonstrates that CNC–SPI nanoconjugate with optimum protein to polysaccharide ratio has great potential as a natural particle stabilizer in food and nutraceutical emulsion applications.

Encapsulation represents one feasible approach of preparing powdered natural rubber. Herein, we demonstrated the preparation of polymethyl methacrylate-grafted natural rubber (PMMA-g-NR) powders th...

In this work, composite powders of natural rubber/silica (NR-SiO2) were prepared via sol-gel and spray drying method. The morphology and physical properties of resultant rubber composite powders were characterized by scanning electron microscopy with energy dispersive X-ray spectrometry, laser light scattering particle sizer and thermogravimetric analyzer. The results showed that spray-dried NR-SiO2 particles were spherical in shape with diameter of less than 10 μm, with silica on the outer layer. The particle size was found to increase gradually with the increase in NR/Si mass ratio. Marginal growth in particle size was observed with increasing feed flow rate. Increasing inlet air temperature improved the latex particle encapsulation by silica layer while maintaining the final particle size. The mechanical properties of NR-SiO2 powders-filled polylactic acid (PLA) composite increase gradually with the addition of dried particles of higher rubber content. However, the composite exhibited relatively lower or reduced tensile strength and elongation at break compared to the host PLA polymer. This could be attributed to poor filler dispersion associated with weak filler/matrix interaction effect occurring during melt-compounding process.

This paper aims to report an aluminum–copper (Al–Cu) die-attach system as a Pb-free alternative for electronic applications. The Al–Cu die-attach system is formulated by a mixture of Al and Cu nanoparticles and a constituent of organic compounds and sintered at 380 °C ± 10 °C without any pressure application. The effects of organic additives on physical, structural, and electrical properties are investigated to understand the die-attach quality of Al–Cu nanopaste. The formation of CuAl2 phase is discovered, which confirmed the joining of Al and Cu nanoparticles in sintered nanopaste layer. Solid-state fusion of Al and Cu can be seen in scanning electron microscope (SEM) analysis. Energy dispersive X-ray (EDX) analysis demonstrates sample of 0.25-g V006A has the lowest oxygen element at 15.36%. Sample with 0.25-g organic additives exhibits the smallest crystallite size and electrical resistivity, which were 8.15 nm and $21~\mu \Omega \cdot \text {cm}$ , which is favorable for high-temperature applications.

Cellulose nanofibers (CNF) isolated from plant biomass have attracted considerable interests in polymer engineering. The limitations associated with CNF-based nanocomposites are often linked to the time-consuming preparation methods and lack of desired surface functionalities. Herein, we demonstrate the feasibility of preparing a multifunctional CNF-zinc oxide (CNF-ZnO) nanocomposite with dual antibacterial and reinforcing properties via a facile and efficient ultrasound route. We characterized and examined the antibacterial and mechanical reinforcement performances of our ultrasonically induced nanocomposite. Based on our electron microscopy analyses, the ZnO deposited onto the nanofibrous network had a flake-like morphology with particle sizes ranging between 21 to 34 nm. pH levels between 8–10 led to the formation of ultrafine ZnO particles with a uniform size distribution. The resultant CNF-ZnO composite showed improved thermal stability compared to pure CNF. The composite showed potent inhibitory activities against Gram-positive (methicillin-resistant Staphylococcus aureus (MRSA)) and Gram-negative Salmonella typhi (S. typhi) bacteria. A CNF-ZnO-reinforced natural rubber (NR/CNF-ZnO) composite film, which was produced via latex mixing and casting methods, exhibited up to 42% improvement in tensile strength compared with the neat NR. The findings of this study suggest that ultrasonically-synthesized palm CNF-ZnO nanocomposites could find potential applications in the biomedical field and in the development of high strength rubber composites.

Chemical disorder in semiconductors is important to characterize reliably because it affects materials performance, for instance by introducing potential fluctuations and recombination sites. It al...

Moderate or Intensive Low-Oxygen Dilution (MILD) combustion as a newly developed technology has drawn much attention all over the world since it features the homogeneous combustion and extremely low NOx emission. Even though reduced NOx emission is reported in pulverized coal MILD combustion, its performance is not as comparable as that of gaseous and liquid fuels. In order to investigate the possibility of further reducing NOx emission in a MILD coal combustion furnace, horizontal fuel-rich/lean burner as another promising technology aiming to regulate NOx emission is employed in this study. Results have shown that fuel-rich/lean burner is able to further reduce NOx emission by about 4% when applied to a MILD coal combustion furnace. This is due to the combined effect of the reduction of thermal- and fuel-NO formation. Particles entrained in the fuel-rich stream is heated in a reducing atmosphere, so that the oxidation of hydrogen cyanide (HCN) and ammonia (NH3) released by volatile is hindered. Moreover, the NO released by char is reduced to molecular nitrogen. Thermal-NO is reduced because of the low local peak temperature in both streams.

Moderate or intense low-oxygen dilution (MILD) combustion is a promising technology for reducing pollutant emissions while maintaining high thermal efficiency. Recently, MILD combustion has been expected to be applied in combination with oxy-fuel combustion for carbon capturing and storage (CCS). This paper presents a numerical study of methane MILD combustion in O2/N2, O2/CO2 and O2/H2O, in order to deepen the knowledge to the combined form, namely oxy-MILD combustion. Firstly, steady computational fluid dynamics (CFD) simulation was carried out inside a closed lab-scale MILD combustion furnace following the previous experiment conducted in O2/N2. Detailed in-furnace temperature and species data as well as laminar flame speed were used to validate the CFD models and the chemical reaction mechanism. Subsequently, flame structure and turbulence/reaction interaction were examined under the three atmosphere conditions. The results suggest that oxy-MILD (diluted with either CO2 or H2O) combustion exhibits larger reaction zone and higher likelihood to be operated under distributed reaction regime in comparison with air-MILD (diluted with N2). Specifically, CO2 is the most preferable diluent among N2, CO2 and H2O to achieve MILD combustion regime.

This paper presents a comprehensive review on the development of the modelling of ash deposition with particle combustion, sticking, rebound and removal behaviors. The modelling of ash deposit morphomology is also included. Ash deposition in coal and biomass fired boilers will induce many ash-related issues (such as slagging, fouling and corrosion) which will reduce the boiler efficiency and capacity. Some traditional prediction methods have been proposed to evaluate ash deposition. However, these methods are based on chemical compositions of ash deposits and the operating temperatures in boilers, which are unable to fully predict the complex ash deposition process. Great efforts have been made to develop mechanistic models to predict ash deposition processes in nature. The behavior of ash formation and deposition in the boilers plays a key role in the design of boilers and the selection of fuels. The ash formation process is primarily due to the fragmentation and coalescence of mineral matters in fuels and only a small portion of ash is formed. When ash particles impact the heat transfer surfaces, only a few particles will deposit on these surfaces and several ash deposition mechanisms have been identified to predict their behaviors, such as inertial impaction (for large particles), thermophoresis (for fine particles) and condensation (for vapors). The ash deposition mechanisms used in the experimental, numerical and mechanistic studies coupled with the fuels and investigated systems are summarized in this paper. Numerous attempts have been made to develop different models to overcome the shortcomings of traditional methods. As such, various numerical attempts have been made to predict the growth behavior of ash deposition in furnaces and boilers by employing comprehensive combustion models coupled with high fidelity computational fluid dynamics (CFD) modelling methods for different types of fuels. Furthermore, several combustion codes have been incorporated into the ash deposition models, including the fuel combustion process (the release of volatiles, devolatilization and char combustion), wall reaction and consumption sub-models as well as the packed bed and overbed combustion sub-models. Moreover, several ash deposition sub-models have been developed to predict the ash deposition growth behavior using computational fluid dynamics (CFD) methods in combustors of different scales. In order to better understand the impact behavior of ash particles, some analytical models such as dynamic models and kinetic models have been developed. For accurate prediction of impaction efficiency, an impaction correction factor has been proposed to reduce the effect of coarse meshes on the impaction efficiency. Also, the stickiness of ash particles which is determined by kinetic energy, viscosity and molten degree of ash particles plays a key role in the ash formation and deposition processes and determines whether ash particles stick on the surfaces or rebound from the surfaces. Briefly, three main types of particle adhesion theories are used to evaluate if an impacting particle bounces off or sticks to the surface, namely, the viscosity-based empirical model, the critical velocity model and the melt fraction model. When the particles impact the heat transfer surfaces, they may rebound from the surface or remove the ash deposit. The particle surface energy with its static contact angle is also important in determining the sticking efficiency. In addition, several rebound criteria have been proposed to predict the particle rebound behavior, which include the critical rebound velocity, energy balance, excess energy, bouncing potential and critical impact angle on a flat or oblique plate or on a heat transfer tube. Tremendous efforts have also been made to develop the theories and mechanisms of ash deposition as well as removal on the surfaces of heat exchangers, some of which were based on the Kern-Seaton theory. Furthermore, several removal sub-models have been proposed to predict the particle removal behavior, including the energy balance, moment conservation, energy dissipation, critical moment theory, critical shear velocity and critical impact angle. In the actual fouling process, the growth behavior of fouling on the tube surfaces changes the original tube shape continuously. The fly ash deposited on the surface alters the boundary of heat transfer and affects the distribution of the temperature, flow field as well as the deposition rates. Various theoretical methods have been proposed to predict the ash deposit morphology, including the lattice Boltzmann method (LBM), dynamic meshing method, and time and mass magnification factors. In addition, many investigations have focused on developing models for inter-particle thermal conductivity by studying the ash deposit microstructure to characterize the thermal and morphological changes through an ash deposit. Several ash deposition layer models have been experimentally and theorectically studied in details, including the two-layer, three-layer, four-layer and six-layer sub-models.

While the economy is rapidly expanding in most emerging countries, issues coupled with a higher population has created foreseeable tension among food, water, and energy. It is crucial for more sustainable valorization of resources, for instance, nanocellulose, to address the core challenges in environmental sustainability. As the complexity of the system evolved, the timescale of project development has increased exponentially. However, research on the design and operation of integrated nanomaterials, along with energy supply, monitoring, and control infrastructure, has seriously lagged. The development cost of new materials can be significantly reduced by utilizing molecular simulation technology in the design of nanostructured materials. To realize its potential, nanocellulose, an amphiphilic biopolymer with the presence of rich -OH and -CH structural groups, was investigated via molecular dynamics simulation to reveal its full potential as Pickering emulsion stabilizer at the molecular level. This work has successfully quantified the Pickering stabilization mechanism profiles by nanocellulose, and the phenomenon could be visualized in three stages, namely the initial homogenous phase, rapid formation of micelles and coalescence, and lastly the thermodynamic equilibrium of the system. It was also observed that the high bead order was always coupled with a high volume of phase separation activities, through a coarse-grained model within 20,000 time steps. The outcome of this work would be helpful to provide an important perspective for the future design and development of nanocellulose-based emulsion products, which cater for food, cosmeceutical, and pharmaceutical industries.

Research and development of nanocellulose and nanocellulose-reinforced composite materials have garnered substantial interest in recent years. This is greatly attributed to its unique functionalities and properties, such as being renewable, sustainable, possessing high mechanical strengths, having low weight and cost. This review aims to highlight recent developments in incorporating nanocellulose into rubber matrices as a reinforcing filler material. It encompasses an introduction to natural and synthetic rubbers as a commodity at large and conventional fillers used today in rubber processing, such as carbon black and silica. Subsequently, different types of nanocellulose would be addressed, including its common sources, dimensions, and mechanical properties, followed by recent isolation techniques of nanocellulose from its resource and application in rubber reinforcement. The review also gathers recent studies and qualitative findings on the incorporation of a myriad of nanocellulose variants into various types of rubber matrices with the main goal of enhancing its mechanical integrity and potentially phasing out conventional rubber fillers. The mechanism of reinforcement and mechanical behaviors of these nanocomposites are highlighted. This article concludes with potential industrial applications of nanocellulose-reinforced rubber composites and the way forward with this technology.

In this work, dolomite filler was introduced into thermoplastic starch (TPS) matrix to form TPS-dolomite (TPS-DOL) biocomposites. TPS-DOL biocomposites were prepared at different dolomite loadings (1 wt%, 2 wt%, 3 wt%, 4 wt% and 5 wt%) and by using two different forms of dolomite (pristine (DOL(P) and sonicated dolomite (DOL(U)) via the solvent casting technique. The effects of dolomite loading and sonication process on the mechanical properties of the TPS-DOL biocomposites were analyzed using tensile and tear tests. The chemistry aspect of the TPS-DOL biocomposites was analyzed using Fourier transform infrared spectroscopy (FTIR) and X-Ray Diffraction (XRD) analysis. According to the mechanical data, biocomposites with a high loading of dolomite (4 and 5 wt%) possess greater tensile and tear properties as compared to the biocomposites with a low loading of dolomite (1 and 2 wt%). Furthermore, it is also proved that the TPS-DOL(U) biocomposites have better mechanical properties when compared to the TPS-DOL(P) biocomposites. Reduction in the dolomite particle size upon the sonication process assisted in its dispersion and distribution throughout the TPS matrix. Thus, this led to the improvement of the tensile and tear properties of the biocomposite. Based on the findings, it is proven that the sonication process is a simple yet beneficial technique in the production of the TPS-dolomite biocomposites with improved tensile and tear properties for use as packaging film.

Carbon nanotubes (CNTs) have, over the years, been used in research as a promising material in electronics as a thermal interface material and as interconnects amongst other applications. However, there exist several issues preventing the widespread integration of CNTs onto device applications, e.g., high growth temperature and interfacial resistance. To overcome these issues, a complementary metal oxide semiconductor (CMOS)-compatible CNT array transfer method that electrically connects the CNT arrays to target device substrates was developed. The method separates the CNT growth and preparation steps from the target substrate. Utilizing an alignment tool with the capabilities of thermocompression enables a highly accurate transfer of CNT arrays onto designated areas with desired patterns. With this transfer process as a starting point, improvement pointers are also discussed in this paper to further improve the quality of the transferred CNTs. Ministry of Education (MOE) Published version This research was funded by Singapore MOE Tier 2, MOE2018-T2-2-105 and Excelitas Technologies Singapore (EDB-IPP).

International audience; In this work, we investigate the performances of vertically aligned carbon nanotube (VACNT) arrays for high frequency interconnects. The frequency range of this study is the W band (75 GHz to 110 GHz). The type of interconnect is coplanar, meaning the interconnect can connect two subparts supporting a coplanar waveguide (CPW) mode. Starting from the promising results of a previously measured device [1] we suggest a way to improve the behavior of VACNT arrays interconnects. We perform full-wave modeling of a new structure that will be fabricated and tested and we compare different modelling approaches for the design of such interconnects.

Two phenomena of dual damascene via open in extremely low local metal pattern density region, and when connected through a narrow width metal line to a big pad opening with high density sea of vias are identified. A systematic study was carried out to investigate the impact of extreme pattern density design on dual damascene via integrity. Local metal density, interconnects metal line width, length, and pad size connecting to an isolated via are investigated to establish the correlation to via open and to explain the failure mechanism. Finally design for manufacturing solution is proposed, apart from process fix as the total solution.

We report a reliable TDDB lifetime projection model using power law verified from 40Mb STT-MRAM macro at sub-ppm failure rate to realize nearly unlimited endurance for cache applications. A specially designed macro, having internal temperature control systems and capable of applying accelerated voltage at 40Mb array level with wide operating temperature range: −40~125 °C and varying pulse widths: 200~10 ns, is used for the study. We demonstrate a superior endurance performance of > 1 E 12 cycles at 1 ppm failure rate using 40Mb macro combined with SRAM -like MTJ stack with lower operating voltage at BER ~ 1 ppm at 1 0 ns write pulse.

Particle-stabilized emulsion systems, namely Pickering emulsions have recently emerged as novel yet attractive dosage form for controlled delivery of biologically active compounds. The stability and properties of emulsions are influenced by formulation and processing factors. In this study, oil-in-water Pickering emulsions were prepared using Fe3 O4 @cellulose nanocrystal (MCNC) nanocomposites and the effects of CNC/Fe3 O4 (CNC/MNP) ratios, MCNC particle concentration Cmcnc, oil volume fraction φoil and ionic strength on the colloidal stability were evaluated. The results showed that stable emulsions could be attained using MCNC particles with CNC/MNP ratio ≤ 1. Increasing CNC/MNP ratio > 1 resulted in different degree of phase separation of emulsions. The average droplet size of MCNC-stabilized Pickering emulsions (MCNC-PE) decreased from 17.34 to 3.58 µm with an increase in Cmcnc as a result of improved coalescence stability due to higher droplet surface coverage Smcnc by MCNC particles. An increase in φoil led to pronounced increase in droplet size from 2.82 to 17.00 µm. Interestingly, the ionic strength showed little or no impact on the emulsion droplet size and creaming. The storage stability study revealed that most emulsions remained fairly stable with no apparent change in droplet size. In conclusion, the physical stability of MCNC-PE was found to be greatly influenced by particulate emulsifier concentration and oil loadings. These two parameters must be well controlled in the development of Pickering emulsions for potential food and pharmaceutical applications.

In the past decades, the implementation of nanotechnology on food has been receiving a great deal of attention. This chapter is focused on the working principle of ultrasound (US) cavitation technology and its potential for nanofood processing and production. US cavitation is well known to generate high shear, free radicals and heat to a system. These 3 products of cavitation can be utilized for nanofoods preparation, processing and preservation. Particularly, the high shear produced by high power ultrasound (HPU) is found to be sufficient for nanoemulsification and nanoencapsulation processes, where emulsion droplets of nanosized can be effectively produced and employed to encapsulate various bioactive compound to work as food supplement that possessed enhanced bioactive delivery performance. Besides, the acoustic compression and extension was noticed to reduce the shell thickness of various foods, which thus easing the water evaporation during spray drying process. The radicals and thermal energy obtained through the US irradiation, on the other hand can be utilized to induce pasteurization to breakdown the cell membrane of microorganisms, thus reducing the harmful effects against food as well as inactivate enzymes that will eventually decrease the shelf life of food. Besides the mentioned applications, the US cavitation can also improved the extraction yield of lipid and nutrients from a plant, which the extracted products can be further emulsified and encapsulated in the form of nanoemulsions. Overall, this chapter provides an overview on the fundamental of US, its potential in nanoemulsification, spray drying, pasteurization and oil extraction for nanofood as well as its future perspectives.

We demonstrate the manufacturable 22nm FD-SOI 40Mb embedded MRAM (eMRAM), by achieving product functionality and reliability at package level across industrial-grade operating temperature range (−40 to 125 °C) with ECC-off mode. The magnetic tunnel junction stack, integration and etch processes were optimized to achieve superior MTJ performances to meet all product requirements. From package level data, we confirmed the product reliability by passing LTOL, HTOL, 1M endurance cycling and 5x solder reflows tests with failure rate < 1 ppm. In addition, we demonstrate the eMRAM capability to cover stand-by magnetic immunity of ~ 600 Oe at 105 °C for 10 years and active-mode magnetic immunity of ~500 Oe.

Future electronic trend is faster speed, larger bandwidth, and higher power. These requirements stimulate the operating frequency of microelectronic devices to higher frequency range. Hence, conventional metal used in the interconnection in circuit would inevitably face skin effect and electromigration issues. Carbon nanotube (CNT) has received much attention due to its superior properties in high frequency applications. In this work, CNT array will be used for two packaging solutions: CNT-based TSV and CNT-based flip-chip. They were fabricated using a newly developed low-temperature CMOS-compatible CNT transfer technique. CNT growth was conducted on a donor substrate before CNT bundles were inserted into via holes or transferred onto chip/carrier to form the desired CNT-based device. Therefore, the device fabrication can be separated from high temperature CNT growth. Experimental studies validate CNT as potential material in RF interconnections.

The pH-responsive characteristic of Fe3O4@CNC (MCNC)-stabilized Pickering emulsions (MCNC-PEs) under the influence of an external magnetic field were investigated. The Pickering emulsions were prepared using MCNC nanocomposites as the emulsifier. The results demonstrated that the MCNC-PEs exhibited reversible pH-dependent stability that was affected by the presence of magnetic fields. The MCNC-PE droplets prepared with 0.3 wt% MCNC was observed to be stable in acidic solution (pH 1.5–5.0) but broken down in alkaline medium (pH ≥ 7.5). This phenomenon could be owing to an abrupt change of MCNC wetting properties as resulted by the combined effects of superparamagnetic hysteresis and high solubility of MCNCs in alkaline environment. The formulated emulsion can be cycled between stable and unstable 3 times upon a simple pH variation. The unique pH-dependent stability was, however, not observed in the emulsion systems prepared using 0.5 wt% MCNCs, suggesting that MCNC-PE with higher degree of surface coverage by MCNC particles were highly stable against both pH changes and magnetic field. This study revealed the reversible inter-droplet stability of MCNC-PEs upon changes in pH with the presence of magnetic field, therefore these engineered emulsions could find potential applications in encapsulation and controlled release of pharmaceutically active compounds.

We studied the formation of palm olein-in-water (O/W) Pickering emulsion stabilized by Fe3O4-cellulose nanocrystals (MCNC) nanocomposites obtained by ultrasound assisted in-situ co-precipitation method. The synthesized MCNC nanocomposites successfully stabilized Pickering emulsion with dual responses. The magnetic tests revealed a direct-relation between attractability of MCNC-stabilized Pickering emulsions and the emulsion droplet diameter. The Pickering emulsions were stable under pH ranging from 3 to 6. The stability substantially reduced around pH 8-10, and regained slowly when approaching pH 13. From microscopic and mastersizer analysis, monodisperse emulsion droplets were noticed at pH 3-6, and 13, while polydisperse emulsion were obtained at pH 8-12. The Pickering emulsions prepared at pH 6 are stable up to 14 days, while Pickering emulsions at pH 8 experienced coalescence. In this study, the dual stimuli-responsive Pickering emulsion stabilized by MCNC may hold potentials for biomedical and drug delivery as new generation of smart nanotherapeutic carrier.

In recent years, the surge in counterfeit products in the microelectronics industry has escalated to problems such as losses and damages of companies’ reputation and consumers’ safety and confidence. With the aim to protect products and devices from attackers to obtain their circuit design, intellectual property (IP) or even secured data, anti-tampering (security) features have been gaining great interest in companies as well as government bodies. With equipment technology advancement, attackers may utilize them to tamper with the devices to retrieve information in an unorthodox manner. Therefore in this report, the motivation for tamper resistant material for IC packaging is first elaborated, follow by literature review conducted from types of integrated circuits (IC) packaging available on the market to the packaging materials, steps taken to produce counterfeit IC and analysis of the internal structure by removal of packaging materials with different techniques (e.g. laser decapsulation). In addition, the rationale of focusing on laser utilization will be mentioned and lastly, the fundamentals of laser and the laser applications in microelectronics will be elaborated. Experiments are conducted on commercial packages and in-house formulated epoxy resin, Glycidyl-POSS (GP), either with or without carbon black/surface treatment on fillers. The components that formed GP, sample preparation processes, laser parameters and the characterization tools utilized will be described. Different types of GP samples prepared are characterized. Images of these GP samples after laser ablation are captured and step profiler is used to quantify the etch depth for analysis. The resistance to laser ablation is obtained, analyzed and discussed. From the data, it is postulated that due to the strong light absorptivity of carbon black, GP samples which do not contain carbon black but with fillers show better resistance to laser ablation in contrast to samples that contain both carbon black and fillers. In addition, the relationship between adhesion of the matrix and fillers to improve stress transfer and its effect on the extent of laser ablation is also studied. Amino silane treated fillers added into GP matrix were used to fabricate good matrix-filler adhesion samples while Glycidyl silane treated fillers added into GP matrix produced samples with poor adhesion. More details of the results and analysis will be explained in this report. Overall, samples without carbon black showed superior performance, being almost laser resistant. This indicates that the carbon black plays the key role as the light absorber and if the material is designed to not absorb any of the laser light, the damage incurred will be very minimal. In the case where colour pigment such as carbon black cannot be omitted (for blocking light transmission) in the device encapsulating process, it is important to reduce air gaps due to poor adhesion between matrix and fillers or pores/voids as all these defects act as the point of weakness which hinder stress transfer, or to find alternative colour pigments which would absorb the laser light less efficiently. Master of Engineering

A 50 GHz carbon nanotube based rectangular resonant cavity is designed, allowing to experimentally obtain the value of the RF conductivity of high-density CNT forests. It also validates a CMOS compatible fabrication process robust to current leakage. A CNT equivalent bulk model is used for 3D electromagnetic simulations and parametric analysis. A new transfer method of CNT forests is considered for the fabrication of the rectangular cavity resonator.

We demonstrate 22-nm FD-SOI 40Mb embedded MRAM (eMRAM) macros for automotive-grade-l (Auto-G1) MCU applications, highlighting sub-ppm to bit error rate and zero failure after 1M endurance cycles across Auto-G1 operating temperature range (-40∼150 °C). Read disturbance characterization with external field also reveals that 40Mb eMRAM macro is capable of active-mode magnetic immunity > 500 Oe at 150 °C. In addition, based on 22-nm eMRAM macro data, we review the effects of magnetic tunnel junction (MTJ) size on reliability and examine scalability of eMRAM technology beyond 22 nm.

The current work proposed an alternative ultrasound (US) technology, namely the high-intensity ultrasonic tubular reactor (HUTR) for preparing Pickering emulsions. Using the non-toxic and environmentally friendly cellulose nanocrystal (CNC) as a solid stabilizer, Pickering emulsions were produced using the HUTR and the results showed that Pickering emulsions as small as 1.5 µm can be produced using HUTR at the US power and sonication time of 300 W and 15 min respectively. Additionally, the sizes of Pickering emulsion obtained are found to remain the same upon 30 days of storage. The performance of HUTR in emulsion preparation is compared to conventional US horn system at the same US power. It was observed that the use of HUTR allowed generation of Pickering emulsion that is significantly smaller (around 7.40 μm) and with better droplet size distribution (Coefficient of variation, CV = 31%) as compared to those prepared with US horn method (12.75 µm, CV = 36%). This is owing to the better distribution of cavitation activity in the treatment chamber of HUTR as compared to those in the horn, according to the sonochemiluminescence (SCL) study. From the 30-days storage stability analysis, the CNC-PE prepared using HUTR was found to more stable against droplet coalescence in comparison to those prepared using US horn. Our findings suggested that the HUTR possessed superior Pickering emulsification capacity when compared to conventional US horn. Further work will be necessary to evaluate the feasibility of such intensifying tubular reactor technology for larger scale emulsification and other process intensification applications.

In this work, iron oxide-mesoporous silica MCM-41 composites were prepared by hydrothermal and impregnation methods, while their adsorption properties were examined by using acetylsalicylic acid as the model of the pharmaceutical pollutant. X-ray diffraction (XRD) patterns and diffuse reflectance ultraviolet–visible (DR UV–vis) spectra showed that the iron oxides (α-Fe 2 O 3 ) were successfully incorporated into the MCM-41. Field emission scanning electron microscopy (FESEM) micrographs revealed that the composites prepared by hydrothermal synthesis exhibited aggregated plate-like α -Fe 2 O 3 particles, while irregular particles were found in the composites prepared by the impregnation method. The adsorption capacity of MCM-41 was greatly improved upon the introduction of α -Fe 2 O 3 . Composites prepared from hydrothermal synthesis displayed excellent adsorption capacity compared to the composites prepared by the impregnation method. This might be due to the better maintained mesostructure of the MCM-41 and the plate-like morphology of the α -Fe 2 O 3 , which might tend to expose more active adsorption site. The interactive behaviour between acetylsalicylic acid and the composites can be well described by the Langmuir isotherm model, suggesting that the adsorption of acetylsalicylic acid is monomolecular layer process.

A series of copper oxide loaded TiO2 was prepared by a photodeposition method. It was clarified through XANES that the added copper species solely existed as highly dispersed Cu(II) and it remained as Cu(II) after the photocatalytic reaction. The prepared CuO/TiO2 with various contents (0.1–5 mol%) were used as photocatalysts for 2,4-dichlorophenoxyacetic acid (2,4-D) degradation under UV, visible, and solar simulator irradiation. Under UV light irradiation, the photocatalytic activity of 2,4-D decomposition increased by a maximum factor of 4.3 compared with unmodified TiO2 when TiO2 was loaded with 0.75 mol% CuO. In contrast, under visible light and solar simulator irradiation, the optimum loading of CuO was much lower (0.1 mol%) and enhancements of 22.5 and 2.4 times higher activities were observed, respectively. These results showed that the different masking effects due to the different light sources led to different optimum amounts of CuO, and the added CuO mostly contributed to the visible light activity of TiO2. Therefore, in addition to the increased charge separation and improved visible light absorption, the masking effect shall also be considered in designing highly active photocatalysts under visible and solar light irradiation.

This study investigates the effects of cellulose nanocrystals (CNCs) on the dispersion and colloidal stability of Fe3O4–cellulose nanocrystal nanocomposites (MCNCs). The hybrid composites were prepared using an ultrasound assisted in situ co-precipitation technique in the presence of cellulose nanocrystals (CNCs) as the dispersant. The microscopy analysis showed that the dispersion of MNPs improved greatly with CNC as dispersant. STEM images showed that the mean particle size of Fe3O4 nanoparticle (MNPs) on all CNC samples was found to be less than 20 nm. However, the MNPs aggregated in the sample with 0.01 wt% of CNC. The colloidal stability improved substantially in the presence of 0.05 wt% CNC, and increasing the CNC concentration any more made no difference to the dispersive properties. The surface charges of MCNCs decreased drastically from −14.6 to −59.7 mV as CNC concentration increase from 0.00 to 1.00 wt%. The amount of MNPs deposited on CNC template decreased considerably as CNC concentration increased. Higher amount of MNPs deposited on the CNC surface gave rise to a higher surface wettability and magnetivity. All MCNC samples exhibited superparamagnetic properties and the saturation magnetization (Ms) of MCNC composites was reduced from 30.798 to 1.625 emu g−1 with increasing CNC content from 0.01 to 1.00 wt%. Overall, the results of the study showed that the incorporation CNC led to an improvement of the MNP dispersion and colloidal stability. The as-prepared MCNCs can be used to stabilize palm olein-based emulsions, suggesting their potential usefulness as nanocarriers in food and drug delivery applications.

The development of functional antimicrobial metal oxide nanocomposite systems based on nanocellulose has been the subject of extensive research in recent years. In addition to its sustainability, biodegradability and non-toxic properties, nanocelullose present an extremely high surface area favoring the selective growth and immobilization of ultrafine metal oxide nanoparticles on the cellulosic surface. In this study, oil palm biomass-derived cellulose nanofiber (CNF) decorated with zinc oxide (ZnO) nanocomposites were produced via ultrasound-assisted in situ co-precipitation approach. The morphology and chemical composition of the as-synthesized ZnO/CNF composites were characterized using field emission scanning electron microscopy (FE-SEM) and Fourier-transform infrared (FT-IR). FE-SEM images revealed the fibrous morphology of nanocomposites with a good distribution of ZnO NPs. The FT-IR analysis confirmed a strong interaction between surface functional groups of CNF and ZnO nanoparticles. The swelling behavior of composites was found to be improved with addition of ZnO nanoparticles in the CNF matrix. The hybrid ZnO-CNF exhibited pronounced antibacterial properties against methicillin-resistant Staphylococcus aureus (MRSA). The findings of present study support the possibility of using this palm CNF-based metallic nanocomposites as nanofillers for wound care application.

Ash deposition on heat transfer surfaces is still a significant problem in existing conventional utility boilers. Understanding the formation of ash deposit is thereby very important, which is helpful to optimize the design and operation procedure of boilers. In this study, a dynamic numerical method based on the commercial software ANSYS FLUENT was developed to predict the growth of ash deposit on the deposition probe in a 300 kW slagging test furnace fired with Zhundong coal. Based on the CFD dynamic mesh technique, both shape variations and surface temperature variations of ash deposit with time were predicted. Time-dependent deposition behaviors on the deposition probe with different initial metal wall temperatures were presented. The simulation results (e.g. thickness, heat flux, surface temperature, and shape of ash deposit) are in good agreement with the experimental data. It shows that increased surface temperature of ash deposit can significantly increase ash deposition mass. It was also determined that the shape variation of ash deposit can obviously reduce the impact mass and deposition mass during ash deposition by the comparative studies. The developed simulation method is proved to be a useful tool to predict ash deposition behavior with more detailed information.

The dynamics of droplet breakup during emulsification is a complicated process due to the interplay between multiple physico-chemical and hydrodynamic factors, especially in an energy-intensive ultrasound-assisted emulsification process. In this work, by mapping the physical processing parameters of ultrasound emulsification into a reduced domain that is governed by the power density and the initial average droplet diameter, a dimensionless parameter that resembles the dynamic breakup potential (η) was established via dimensional analysis. In addition to shedding important insights into the emulsification process, η further facilitates the establishment of a transient scaling relationship that is a function of the characteristic value (a) of the emulsion system. Experimental case study on a cellulose nanocrystals (CNC)-based olein-in-water emulsion system prepared via ultrasound cavitation confirmed the validity of the scaling relationship and sub-universal self-similarity was observed. Using the proposed model, good predictions of the transient of droplet size evolution were attained where the value of η, i.e. the proportionality constant, can be conveniently computed using data from a single time point. Application on other emulsion systems further suggested that the value of a possibly indicates the relative minimum size limit of a particular fluids-emulsifier system. Our approach is general, which encourages widespread adoption for emulsification related studies.

We demonstrate a fully functional embedded MRAM (eMRAM) macro integrated into a 22-nm FD-SOI CMOS platform. This macro combined with eFlash-flavor MTJ film stacks shows median-die bit error rate (BER) < 1 ppm after 5× solder reflows. It also meets the automotive grade-1 data retention requirement and shows intrinsic stand-by magnetic immunity of 1.4 kOe (BER criteria = 1 ppm) after 1-hr exposure at 25 °C. The results reveal that eMRAM is capable of serving a broad spectrum of eFlash applications at 22 nm or beyond.

The properties of large grain cuprous oxide (Cu2O) foils are explored after the implementation of a controlled postgrowth annealing process. P -type foils with a wide range of carrier density are demonstrated, enabling a promising processing window for wide bandgap solar cell devices. Hall measurements at room temperature show increased majority carrier concentration after nitrogen annealing and a reduction in mobility. The progressive change in resistivity with annealing temperature is shown, with values approaching 100 Ω·cm. Carrier recombination, measured by microwave photoconductance decay, shows a discrete change upon annealing.

Titanium dioxide (TiO2) has been recognized as an active photocatalyst for degradation of various organic pollutants. In this study, in order to improve the photocatalytic activity of TiO2, the effect of lanthanum oxide modification was investigated by using commercial P25 as the benchmark. Lanthanum oxide/P25 TiO2 composites with 0.1, 0.5, 1 and 5 mol% of La loadings were prepared via an impregnation method. The resultant composites were characterized by X-ray diffraction (XRD), UV-Vis absorption spectroscopy, transmission electron microscopy (TEM), inductively coupled plasma optical emission spectrometry (ICP-OES) and electrochemical impedance spectroscopy (EIS). It was confirmed that the addition of lanthanum oxide did not much affect the crystallinity, crystal structure and the morphology of P25 TiO2. The catalytic activities of the lanthanum oxide/P25 TiO2 catalysts were tested by using 2,4-dichlorophenoxyacetic acid (2,4-D) as the test pollutant and UV light as the irradiation source. The reaction was caried out for 1 hour at room temperature and the percentage removal was determined using a UV spectrophotometer. The results showed that La loading was an important factor that influenced the photocatalytic activity of the composites. After 1 hour reaction, the best catalyst with 0.1 mol% of La loading showed 24% higher photocatalytic activity than the unmodified P25 TiO2 catalyst. It is shown by EIS that the enhanced photocatalytic activity of the composites was due to the ability of lanthanum oxide in improving the charge separation of the photogenerated electron-hole pairs in TiO2.

We demonstrate a numerical analysis of the device impact of photon reabsorption on single-junction GaAs and tandem GaAs/Si solar cells. A self-consistent optical–electrical model that considers nonideal losses within the devices is developed. For single-junction devices, we find that the impact of photon recycling on the voltage increases monotonically with the injection level. For record-level GaAs solar cells, the voltage boost is 33 mV under open-circuit conditions and 13 mV at the maximum power point. For tandem GaAs/Si solar cells, photon reabsorption moderates the sensitivity of tandem efficiency to both obvious parameters like absorber thickness and implicit parameters like shunt resistance ( $R_{{\rm sh}}$ ) and bulk lifetime. Considering luminescent coupling results in a GaAs top cell that is 9.5% thicker than without luminescent coupling. The tandem device is 50% more sensitive to $R_{{\rm sh}}$ changes in the GaAs cell than $R_{{\rm sh}}$ changes in the Si cell. The impact of the GaAs top-cell bulk lifetime on tandem efficiency is reduced by 61% if photon reabsorption is not considered. This integrated optoelectronic device model allows one quantification of the implicit effects of photon recycling and luminescent coupling on device parameters for GaAs/Si tandem, providing a valuable tool for high-performance device optimization.

Secondary phase segregation is hypothesized to have detrimental impacts on Cu 2 ZnSnS 4 (CZTS) thin-film solar cells. In this study, we demonstrate the potential of using kinetic stabilization to inhibit phase decomposition in CZTS. By growing CZTS films at low temperature, we achieve a kinetically stabilized alloy with an expanded solid solution window in the pseudoternary CuS-ZnS-SnS phase diagram. Using X-ray absorption spectroscopy, we study the structural evolution and stability of this metastable alloy upon annealing. For near-stoichiometric samples, we observe a continuous emergence of short-range order toward crystalline CZTS that is nearly complete after a 1-min anneal at 450 °C. For Zn-rich samples, we detect precipitation of ZnS upon annealing, which suggests that the excess Zn exists as cation antisite defects in metastable CZTS.

Oil-in-water (O/W) emulsion-gel systems containing high oil payloads are of increasing interest for food applications because of the reduction in encapsulation cost, consumption frequency or volume of food products. This study shows a facile approach to prepare stable alginate-based O/W emulsions at high oil loading using a mixture of nonionic surfactants (Tween 80 and Span 20) as a template to form gelled-emulsions. The synergistic effects of alginate and surfactants on the O/W emulsion properties were evaluated in terms of oil droplet size and emulsion stability. At 2% (w/v) of alginate and 1% (w/v) of surfactants, the size distribution of oil droplets was narrow and monomodal, even at an oil loading of 70% (v/v). The emulsions formed were stable against phase separation. The oil droplet size could be further reduced to below 1 μm using a high-shear homogenizer. The emulsions formed could be easily molded and gelled into solids of different shapes via ionic gelation. The findings of this study create possible avenues for applications in food industries.

This study investigated the effects of electrical stimulation with theta burst stimulation (eTBS) on seizure suppression. Optimal parameters of eTBS were determined through open-loop stimulation experiments and then implemented in a close-loop seizure control system. For the experiments, 4-aminopyridine (4-AP) was injected into the right hippocampus of Sprague–Dawley rats to induce an acute seizure. eTBS was applied on the ventral hippocampal commissure and the effects of eTBS with different combinations of burst frequency and number of pulses per burst were analyzed in terms of seizure suppression. A closed-loop seizure control system was then implemented based on optimal eTBS parameters. The efficiency of the closed-loop eTBS was evaluated and compared to that of high frequency stimulation. The results show that eTBS induced global suppression in the hippocampus and this was sustained even after the application of eTBS. The optimal parameter of eTBS in the open-loop stimulation experiments was a burst frequency at 100 Hz with nine pulses in a burst. The eTBS integrated with the on–off control law yielded less actions and cumulative delivered charge, but induced longer after-effects of seizure suppression compared to continuous high frequency stimulation (cHFS). To conclude, eTBS has suppressive effects on 4-AP induced seizure. A closed-loop eTBS system provides a more effective way of suppressing seizure and requires less effort compared to cHFS. eTBS may be a novel stimulation protocol for effective seizure control.

Novel nanoemulsion-based drug delivery systems (DDS) have been proposed as alternative and effective approach for the delivery of various types of poorly water-soluble drugs in the last decade. This nanoformulation strategy significantly improves the cell uptake and bioavailability of numerous hydrophobic drugs by increasing their solubility and dissolution rate, maintaining drug concentration within the therapeutic range by controlling the drug release rate, and reducing systemic side effects by targeting to specific disease site, thus offering a better patient compliance. To date, cavitation technology has emerged to be an energy-efficient and promising technique to generate such nanoscale emulsions encapsulating a variety of highly potent pharmaceutical agents that are water-insoluble. The micro-turbulent implosions of cavitation bubbles tear-off primary giant oily emulsion droplets to nano-scale, spontaneously leading to the formation of highly uniform drug contained nanodroplets. A substantial body of recent literatures in the field of nanoemulsions suggests that cavitation is a facile, cost-reducing yet safer generation tool, remarkably highlighting its industrial commercial viability in the development of designing novel nanocarriers or enhancing the properties of existing pharmaceutical products. In this review, the fundamentals of nanoemulsion and the principles involved in their formation are presented. The underlying mechanisms in the generation of pharmaceutical nanoemulsion under acoustic field as well as the advantages of using cavitation compared to the conventional techniques are also highlighted. This review focuses on recent nanoemulsion-based DDS development and how cavitation through ultrasound and hydrodynamic means is useful to generate the pharmaceutical grade nanoemulsions including the complex double or submicron multiple emulsions.

A key requirement for large-scale deployment of photovoltaic technologies is the development of highly functional materials with controllable opto-electronic properties. In this work, we report on the room-temperature synthesis of disordered alloys of the Earth-abundant, tetrahedrally coordinated semiconductors Cu 2 SnS 3 , Cu 2 ZnSnS 4 (CZTS), and ZnS as (Cu 2 SnS 3 ) 1− x (ZnS) x . The resulting disordered semiconductors are found to have continuously and independently tunable optical and electronic properties. Quasi-isovalent alloying on the cation sublattice allows the optical band gap to be varied continuously from 1.1 eV to 2.8 eV. Aliovalent alloying leads to independent control of carrier concentration over at least three orders of magnitude. A conceptual framework describing these disordered materials is presented, in which the structural disorder, constrained by local tetrahedral coordination of both anions and cations, leads to the observed high degree of tunability of the opto-electronic properties. These materials are not only independently interesting, but the developed framework also applies to the opto-electronic properties of kesterite CZTS materials as well as provides a basis for the development of new semiconductors.

The power conversion efficiency of solar cells based on copper (I) oxide (Cu2 O) is enhanced by atomic layer deposition of a thin gallium oxide (Ga2 O3 ) layer. By improving band-alignment and passivating interface defects, the device exhibits an open-circuit voltage of 1.20 V and an efficiency of 3.97%, showing potential of over 7% efficiency.

Spectroscopic ellipsometry (SE) is the technique of choice to determine material properties of thin films in a fast and non-destructive way. However, its ability to accurately extract the material properties of thin films deposited on rough substrate surfaces still remains a challenge, due to depolarization of specularly reflected light. In this paper we present a method based on SE to determine the properties of thin films on rough surfaces. It is shown that, by analyzing SE data only at discrete photon energies, information such as the film thickness and the refractive index at these photon energies can be extracted. The discrete photon energies selected in this method can be related to destructive interference of light at the thin-film surfaces, which significantly reduces the depolarization problem. The method is demonstrated using thin amorphous hydrogenated silicon nitride (a-SiN x :H) films deposited on both polished and rough silicon wafer substrates. By varying the a-SiN x :H film thickness, it is shown that the depolarization effect of light is strongly dependent on the incident photon energies due to light interference at the surface of the a-SiN x :H film. Based on this observation, energy selective ellipsometry (ESE) is proposed as a technique for analyzing thin films on random rough surfaces. It is shown that a-SiN x :H films with a wide range of thickness and optical properties on rough silicon surfaces can be studied accurately by means of ESE. This technique is expected to have useful practical applications, for example in photovoltaics where films are typically deposited onto textured substrates as a means of enhancing light trapping.

The production of palm oil-based submicron emulsions in the presence of Tween 80 has been studied in a liquid whistle hydrodynamic cavitation reactor (LWHCR). Preliminary investigations have been carried out using two orifice plates with the hole diameters of 0.0010 and 0.0016 cm with an aim of investigating the efficiency of LWHCR in the oxidation of aqueous solution of potassium iodide (KI). Based on the preliminary studies, the orifice plate with the smallest hole diameter was chosen for the generation of submicron emulsions. The effect of operating parameters of LWHCR such as the distance between the orifice plate and blade (0.5, 0.6, and 0.8 cm) and the inlet operating pressures (400, 600, and 800 psi) has been successfully investigated and optimized. It has been observed that the minimum droplet size of 476 nm with a PDI of 0.5 was achieved using an orifice plate–blade distance of 0.6 cm and at an inlet operating pressure of 800 psi. Furthermore, the influence of the addition of a co-surfactant, Spa...

This paper reports the formation of Ni–CdSe core–shell structures. The Ni–CdSe core–shell structures were synthesized via a seed-mediated growth method where a CdSe shell was grown on preformed nickel core particles. The types of nickel cores include nickel nanocubes of 13 nm in size and spherical nickel nanoparticles of 11 and 45 nm in size. The coating of 37 nm nickel carbide is also included for comparison. The resultant thickness and morphology of the CdSe shell layer varied depending on the size, shape, and composition of the nickel-based core particles used. High-resolution transmission electron microscopy characterization and analysis of the Ni–CdSe interface led to further understanding of the factors governing the growth between these two phases. Optical and magnetic characterizations were also carried out on selected samples. The use of nickel-based cores with different size, shape, and composition allows the thickness and morphology of the CdSe shell layer to be controlled. This led to the chan...

The present investigation focuses in investigating the effect of osmotic pressure, gelling on the mean droplet diameter, polydispersity index, droplet size stability of the developed novel Aspirin containing water-in-oil-in-water (W/O/W) nano multiple emulsion. The aspirin-loaded nano multiple emulsion formulation was successfully generated using two-stage ultrasonic cavitational emulsification which had been reported in author's previous study. The osmotic behavior of ultrasonically prepared nano multiple emulsions were also examined with different glucose concentrations both in the inner and outer aqueous phases. In addition, introducing gelatin into the formulation also observed to play an important role in preventing the interdroplet coalescence via the formation of interfacial rigid film. Detailed studies were also made on the possible mechanisms of water migration under osmotic gradient which primarily caused by the permeation of glucose. Besides, the experimental results have shown that the interfacial tension between the two immiscible phases decreases with varying the composition of organic phase. Although the W/O/W emulsion prepared with the inner/outer glucose weight ratio of 1-0.5% (w/w) showed an excellent droplet stability, the formulation containing 0.5% (w/w) glucose in the inner aqueous phase appeared to be the most stable with minimum change in the mean droplet size upon one-week storage period. Based on the optimization, nano multiple emulsion droplets with the mean droplet diameter of around 400 nm were produced using 1.25% (w/w) Span 80 and 0.5% Cremophore EL. Overall, our investigation makes a pathway in proving that the use of ultrasound cavitation is an efficient yet promising approach in the generation of stable and uniform nano multiple emulsions and could be used in the encapsulation of various active pharmaceutical ingredients in the near future.

In the present investigation, the operating efficiency of a bench-top air-driven microfluidizer has been compared to that of a bench-top high power ultrasound horn in the production of pharmaceutical grade nanoemulsions using aspirin as a model drug. The influence of important process variables as well as the pre-homogenization and drug loading on the resultant mean droplet diameter and size distribution of emulsion droplets was studied in an oil-in-water nanoemulsion incorporated with a model drug aspirin. Results obtained show that both the emulsification methods were capable of producing very fine nanoemulsions containing aspirin with the minimum droplet size ranging from 150 to 170 nm. In case of using the microfluidizer, it has been observed that the size of the emulsion droplets obtained was almost independent of the applied microfluidization pressure (200-600 bar) and the number of passes (up to 10 passes) while the pre-homogenization and drug loading had a marginal effect in increasing the droplet size. Whereas, in the case of ultrasound emulsification, the droplet size was generally decreased with an increase in sonication amplitude (50-70%) and period of sonication but the resultant emulsion was found to be dependent on the pre-homogenization and drug loading. The STEM microscopic observations illustrated that the optimized formulations obtained using ultrasound cavitation technique are comparable to microfluidized emulsions. These comparative results demonstrated that ultrasound cavitation is a relatively energy-efficient yet promising method of pharmaceutical nanoemulsions as compared to microfluidizer although the means used to generate the nanoemulsions are different.

Mechanical stress sensors based on silicon piezoresistance have limited sensitivity. Mechanical stress sensors based on the on-current or off-current or threshold voltage of silicon MOS transistors also have limited sensitivity. In this paper, we report that the sensitivity of a silicon-based mechanical sensor can be significantly improved by simply monitoring the gate-induced-drain leakage (GIDL) current of an n-channel MOS transistor. The role of a tensile mechanical stress bias will also be discussed.