Thermal properties of carbon black aqueous nanofluids for solar absorption

Carbonaceous Materials-Based Photothermal Process in Water Treatment: From Originals to Frontier Applications

The photothermal process has attracted considerable attention in water treatment due to its advantages of low energy consumption and high efficiency. In this respect, photothermal materials play a crucial role in the photothermal process. Particularly, carbonaceous materials have emerged as promising candidates for this process because of exceptional photothermal performance. While previous research on carbonaceous materials has primarily focused on photothermal evaporation and sterilization, there is now a growing interest in exploring the potential of photothermal effect-assisted advanced oxidation processes (AOPs). However, the underlying mechanism of the photothermal effect assisted by carbonaceous materials remains unclear. This review aims to provide a comprehensive review of the photothermal process of carbonaceous materials in water treatment. It begins by introducing the photothermal properties of carbonaceous materials, followed by a discussion on strategies for enhancing these properties. Then, the application of carbonaceous materials-based photothermal process for water treatment is summarized. This includes both direct photothermal processes such as photothermal evaporation and sterilization, as well as indirect photothermal processes that assisted AOPs. Meanwhile, various mechanisms assisted by the photothermal effect are summarized. Finally, the challenges and opportunities of using carbonaceous materials-based photothermal processes for water treatment are proposed.

The hidden cochlear implant

OBJECTIVE

The hidden cochlear implant concept has two data transmission methods: Bluetooth low energy and transtympanic optical data transfer systems. This study aimed to present the hidden cochlear implant and compare the test results with the existing fully implanted cochlear implant.

METHOD

The Bluetooth low energy module was implanted into the implant bed. For the transtympanic optical data transfer tests, a receiver was passed through the posterior tympanotomy, and the transmitter was placed in the ear canal.

RESULTS

The Bluetooth low energy module range was 5.2-17.5 m. Transtympanic optical data transfer reached a rate of 1 Mbit/s and had 99.22 per cent accuracy. Despite various obstacles, the accuracy of the transtympanic optical data transfer was more than 99 per cent with a 250 Kbit/s rate. The average power consumption was 310 mW for the implanted Bluetooth low energy module and 41 mW for the transtympanic optical data transfer receiver.

CONCLUSION

Bluetooth low energy is suitable to be used transcutaneously. Transtympanic optical data transfer is an effective and promising technology. Hidden use cochlear implants aim to have the aesthetics of a fully implantable cochlear implant with higher reliability and a magnet-free design with smart device integration.

Mobile Efficient Diagnostics of Infectious Diseases via On-Chip RT-qPCR: MEDIC-PCR

The COVID-19 outbreak has caused public and global health crises. However, the lack of on-site fast, reliable, sensitive, and low-cost reverse transcription polymerase chain reaction (RT-PCR) testing limits early detection, timely isolation, and epidemic prevention and control. Here, the authors report a rapid mobile efficient diagnostics of infectious diseases via on-chip -RT-quantitative PCR (RT-qPCR): MEDIC-PCR. First, the authors use a roll-to-roll printing process to accomplish low-cost carbon-black-based disposable PCR chips that enable rapid LED-induced photothermal PCR cycles. The MEDIC-PCR can perform RT (3 min), and PCR (9 min) steps. Further, the cohort of 89 COVID-19 and 103 non-COVID-19 patients testing is completed by the MEDIC-PCR to show excellent diagnostic accuracy of 97%, sensitivity of 94%, and specificity of 98%. This MEDIC-PCR can contribute to the preventive global health in the face of a future pandemic.

Multifunctional Fiber-Based Optoacoustic Emitter as a Bidirectional Brain Interface

A bidirectional brain interface with both "write" and "read" functions can be an important tool for fundamental studies and potential clinical treatments for neurological diseases. Herein, a miniaturized multifunctional fiber-based optoacoustic emitter (mFOE) is reported thatintegrates simultaneous optoacoustic stimulation for "write" and electrophysiology recording of neural circuits for "read". Because of the intrinsic ability of neurons to respond to acoustic wave, there is no requirement of the viral transfection. The orthogonality between optoacoustic waves and electrical field provides a solution to avoid the interference between electrical stimulation and recording. The stimulation function of the mFOE is first validated in cultured ratcortical neurons using calcium imaging. In vivo application of mFOE for successful simultaneous optoacoustic stimulation and electrical recording of brain activities is confirmed in mouse hippocampus in both acute and chronical applications up to 1 month. Minor brain tissue damage is confirmed after these applications. The capability of simultaneous neural stimulation and recording enabled by mFOE opens up new possibilities for the investigation of neural circuits and brings new insights into the study of ultrasound neurostimulation.

Mainstream nitrogen removal from low temperature and low ammonium strength municipal wastewater using hydrogel-encapsulated comammox and anammox

Application of partial nitritation (PN)-anammox to mainstream wastewater treatment faces challenges in low water temperature and low ammonium strength. In this study, a continuous flow PN-anammox reactor with hydrogel-encapsulated comammox and anammox was designed and operated for nitrogen removal from mainstream wastewater with low temperature. Long-term operation with synthetic and real wastewater as the feed demonstrated nearly complete ammonium and total inorganic nitrogen (TIN) removal by the reactor at temperatures as low as 10 °C. A significantly decreased nitrogen removal performance and biomass activity was observed in the reactor at 4 °C before a selective heating strategy was employed. A novel heating technology using radiation to heat carbon black co-encapsulated in the hydrogel matrix with biomass was used to selectively heat biomass but not water in the treatment system. This selective heating technology enabled nearly complete ammonium removal and 89.4 ± 4.3 % TIN removal at influent temperature of 4 °C and reactor temperature 5 °C. Activity tests suggested selective heating brought the biomass activity at influent temperatures of 4 °C and reactor temperature 5 °C to a level comparable to that at 10 °C. Comammox and anammox were consistently present in the system and spatially organized in the hydrogel beads as revealed by qPCR and fluorescence in-situ hybridization (FISH). The abundance of comammox largely decreased by 3 orders of magnitude during the operation at 4 °C, and rapidly recovered after the application of selective heating. The anammox-comammox technology tested in this study essentially enabled mainstream shortcut nitrogen removal, and the selective heating ensured good performance of the technology at temperature as low as 5 °C.

Nanomaterial-enabled photothermal-based solar water disinfection processes: Fundamentals, recent advances, and mechanisms

The pathogenic microorganisms in water pose a great threat to human health. Photothermal and photothermocatalytic disinfection using nanomaterials (NPs) has offered a promising and effective strategy to address the challenges in solar water disinfection (SODIS), especially in the point-of-use operations. This review aims at providing comprehensive and state-of-the-art knowledge of photothermal-based disinfection by NPs. The fundamentals and principles of photothermal-based disinfection were first introduced. Then, recent advances in developing photothermal/photothermocatalytic catalysts were systematically summarized. The light-to-heat conversion and disinfection performance of a large variety of photothermal materials were presented. Given the complicated mechanisms of photothermal-based disinfection, the attacks from reactive oxygen species and heat, the destruction of bacterial cells, and the antibacterial effects of released metal ions were highlighted. Finally, future challenges and opportunities associated with the development of cost-effective photothermal/photothermocatalytic disinfection systems were outlined. This review will provide guidance in designing future NPs and inspire more research efforts from environmental nano-communities to move towards practical water disinfection operations.

Etruscan Fine Ware Pottery: Near-Infrared (NIR) Spectroscopy as a Tool for the Investigation of Clay Firing Temperature and Atmosphere

Fine ware pottery from the Etruscan town of Tarquinia, whose necropolis in inscribed in the list of UNESCO sites, was studied by means of near-infrared (NIR) diffuse reflection spectroscopy. The aim was to investigate the correlation between the firing conditions of the illitic-calcareous local clay, in terms of temperature and atmosphere, and the physical properties of the ceramic paste, usually exploited by the archaeologists for a classification of pottery sherds. For comparison, analytical data related to the mineralogical composition of the samples were obtained by X-ray diffraction and Fourier-transform infrared (FTIR) spectroscopy. Spectroscopic data were elaborated by methods of multivariate analysis.

Waste Egg Tray and Toner-Derived Highly Efficient 3D Solar Evaporator for Freshwater Generation

With the advancement of civilization, water purification, as well as management and disposal of ever-increasing municipal solid waste (MSW), and e-waste, have become global concerns. To address these issues in a sustainable way, a 3D solar evaporator has been proposed in this paper by repurposing recycled paper from MSW in the form of egg trays and waste dry toner (e-waste) using a facile fabrication method. The unique 3D porous structure, fibrous surface, superior water absorbing capability as well as low thermal conductivity of wastepaper-derived egg trays make them an excellent candidate for an efficient solar evaporator, while the waste toner powder coating significantly enhances the optical absorbance capacity. Under 1 sun illumination, the proposed solar evaporator demonstrates an excellent evaporation rate and efficiency of 1.3 kg/m² h and 78.5%, respectively. Moreover, the competitive advantage of the 3D structure in collecting solar irradiance at various light incident angles in comparison to a 2D structure, excellent cycle stability, low processing temperature, and the use of low-cost waste materials enable its use for large-scale water purification systems.

Hybrid Nanofluids as Renewable and Sustainable Colloidal Suspensions for Potential Photovoltaic/Thermal and Solar Energy Applications

The comparative utilization of solar thermal or photovoltaic systems has significantly increased to fulfill the requirement of electricity and heat since few decades. These hybrid systems produce both thermal and electrical energy simultaneously. In recent times, increasing interest is being redirected by researchers in exploiting variety of nanoparticles mixed with miscellaneous base fluids (hybrid nanofluid) for these hybrid systems. This new class of colloidal suspensions has many fascinating advantages as compared to conventional types of nanofluids because of their modified and superior rheological and thermophysical properties which makes them appealing for solar energy devices. Here, we have attempted to deliver an extensive overview of the synthetic methodologies of hybrid nanofluids and their potential in PV/T and solar thermal energy systems. A detailed comparison between conventional types of nanofluids and hybrid nanofluids has been carried out to present in-depth understanding of the advantages of the hybrid nanofluids. The documented reports reveal that enhanced thermal properties of hybrid nanofluids promise the increased performance of solar thermal PV/T systems. Additionally, the unique properties such as nanoparticles concentration and type of base fluid, etc. greatly influence the behavior of hybrid nanofluidic systems. Finally, the outlook, suggestions, and challenges for future research directions are discussed.

Ordered nanostructures arrays fabricated by anodic aluminum oxide (AAO) template-directed methods for energy conversion

Clean and efficient energy conversion systems can overcome the depletion of the fossil fuel and meet the increasing demand of the energy. Ordered nanostructures arrays convert energy more efficiently than their disordered counterparts, by virtue of their structural merits. Among various fabrication methods of these ordered nanostructures arrays, anodic aluminum oxide (AAO) template-directed fabrication have drawn increasing attention due to its low cost, high throughput, flexibility and high structural controllability. This article reviews the application of ordered nanostructures arrays fabricated by AAO template-directed methods in mechanical energy, solar energy, electrical energy and chemical energy conversions in four sections. In each section, the corresponding advantages of these ordered nanostructures arrays in the energy conversion system are analysed, and the limitation of the to-date research is evaluated. Finally, the future directions of the ordered nanostructures arrays fabricated by AAO template-directed methods (the promising method to explore new growth mechanisms of AAO, green fabrication based on reusable AAO templates, new potential energy conversion application) are discussed.

The efficacy and the adverse reactions of laser-assisted tattoo removal - a prospective split study using nanosecond and picosecond lasers

BACKGROUND

Laser pulses with nanosecond duration (NSL) have been the golden standard to destroy the pigment particles in skin. It is still controversially discussed whether picosecond pulses (PSL) are superior for tattoo removal.

OBJECTIVES

To compare the efficacy and the adverse reactions of nanosecond and picosecond laser pulses in a comparative study.

METHODS

The prospective study included 23 subjects with 30 black or coloured tattoos, which were split into two halves treated with either a new PSL (532, 1064 nm) or standard NSL (694 nm). The lasers were applied at regular time intervals of 4 weeks for up to eight treatments. Tattoo clearance (primary endpoint), pain and adverse reactions (secondary endpoints) were appraised by physicians, blinded observers, and by subjects. The extent and duration of adverse reactions were additionally assessed by using a questionnaire and photo-documentation after each treatment session.

RESULTS

The tattoo clearance appeared to be more effective for PSL compared to NSL but without statistical significance (P > 0.05). Pretreated tattoos responded better to laser treatments than previously untreated tattoos. Subjects felt significantly less pain with PSL than with NSL (P < 0.001). Transient adverse reactions were statistically less pronounced lasting shorter for PSL as for NSL, especially blistering, pruritus, and burning sensation. Hypopigmentation appeared after NSL treatments only, whereas hyperpigmentation was caused by both lasers. No scarring was detected with either laser.

CONCLUSIONS

Both laser systems enable acceptable clearance of most tattoos in the present study. PSL cause less collateral skin damage as compared to NSL.

Synthesis, characterisation and thermo-physical properties of highly stable graphene oxide-based aqueous nanofluids for potential low-temperature direct absorption solar applications

Two types of highly stable 0.1% graphene oxide-based aqueous nanofluids were synthesised and investigated. The first nanofluid (GO) was prepared under the influence of ultrasonic irradiation without surfactant. The second nanofluid was treated with tetra ethyl ammonium hydroxide to reduce the graphene oxide to form reduced graphene oxide (RGO) during ultrasonic irradiation. The GO and RGO powders were characterised by various techniques such as field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Raman. Also UV–visible absorption spectroscopy was carried out and band gap energies were determined. Optical band gap energies for indirect transitions ranged from 3.4 to 4.4 eV and for direct transitions they ranged between 2.2 and 3.7 eV. Thermal conductivity measurements of the GO-based aqueous nanofluid revealed an enhancement of 9.5% at 40 °C compared to pure water, while the RGO-based aqueous nanofluid at 40 °C had a value 9.23% lower than pure water. Furthermore, the photothermal response of the RGO-based aqueous nanofluid had a temperature increase of 13.5 °C, (enhancement of 60.2%) compared to pure water, the GO-based aqueous nanofluid only displayed a temperature rise of 10.9 °C, (enhancement of 46.6%) after 20 min exposure to a solar irradiance of 1000 W m⁻². Both nanofluid types displayed good long-term stability, with the GO-based aqueous nanofluid having a zeta potential of 30.3 mV and the RGO-based aqueous nanofluid having a value of 47.6 mV after 6 months. The good dispersion stability and photothermal performance makes both nanofluid types very promising working fluids for low-temperature direct absorption solar collectors.

Vapor-phase production of nanomaterials

The synthesis of nanomaterials, with characteristic dimensions of 1 to 100 nm, is a key component of nanotechnology. Vapor-phase synthesis of nanomaterials has numerous advantages such as high product purity, high-throughput continuous operation, and scalability that have made it the dominant approach for the commercial synthesis of nanomaterials. At the same time, this class of methods has great potential for expanded use in research and development. Here, we present a broad review of progress in vapor-phase nanomaterial synthesis. We describe physically-based vapor-phase synthesis methods including inert gas condensation, spark discharge generation, and pulsed laser ablation; plasma processing methods including thermal- and non-thermal plasma processing; and chemically-based vapor-phase synthesis methods including chemical vapor condensation, flame-based aerosol synthesis, spray pyrolysis, and laser pyrolysis. In addition, we summarize the nanomaterials produced by each method, along with representative applications, and describe the synthesis of the most important materials produced by each method in greater detail.

Light-Responsive Nanofibrous Motor with Simultaneously Precise Locomotion and Reversible Deformation

Light-powered micromotors have drawn enormous attention because of their potential applications in cargo delivery, environmental monitoring, and noninvasive surgery. However, the existing micromotors still suffer from some challenges, including slow speed, poor controllability, single locomotion mode, and no deformation during movement. Herein, we employ a combined electrospinning with brushing of Chinese ink to simply fabricate a light-responsive gradient-structured poly(vinyl alcohol)/carbon (PVA/carbon) composite motor. Because of the surface deposition and ultrahigh loading amount of carbon nanoparticles (ca. 43%), the motor exhibits rapid (39 mm/s), direction-controlled, and multimodal locomotion (vertical movement, horizontal motion, rotation) under light irradiation. Simultaneously, gradient alignment structure of the PVA nanofibrous matrix endows the motor with controllable and reversible deformation during locomotion. We finally demonstrate the potential applications of the motors in leakage monitoring, object salvage, smart access, and intelligent assembly. The present work will inspire the design of novel photosensitive motors for applications in various fields, such as microrobots, environmental monitoring, and biomedicine.

Fabrication and Stabilization of Oxidized Carbon Black Nanoparticle Dispersion in Aqueous Solution for Photothermal Conversion Enhancement

This study aims to explore oxidized carbon black nanoparticles (OCB-NPs) capped with an inorganic surfactant dispersed in water, as a carbon black water-based nanofluid, on photothermal conversion enhancement. We used ultraviolet-visible (UV-vis) absorption spectroscopy and zeta potential analyzers to identify the optimal concentration of sodium hexametaphosphate (SHMP) as an inorganic surfactant for OCB-NPs in order to determine the maximum value of UV-vis light absorption and absolute zeta potential. Then, the concentrations of 0.025-0.1 wt % OCB water-based nanofluid with SHMP were formulated by an ultrasonic bath for the examination of rheological behavior, thermal conductivity, and heating rate. The results indicated that the heating rate improvement of the water-based nanofluid involving 0.1 wt % OCB-capped with SHMP after irradiation by UV-vis light with wavelengths ranging from 220 to 380 nm, which is included in the solar spectrum, and an intensity of 205 W/m² increased by approximately 66%, compared to the base fluid in the cyclic flow system. Furthermore, after a 1 month storage period, the dispersion stabilization of water-based nanofluid including 0.1 wt % OCB-capped with SHMP reached 98%, as estimated by the UV-vis spectrophotometer.

New Pure Organic and Peroxide-Free Redox Initiating Systems for Polymerization in Mild Conditions

Redox initiating systems (RISs) are highly worthwhile for polymerization in mild conditions (at room temperature—RT) without external thermal or light activation. With high performance redox initiating systems RIS, the free radical polymerization FRP can even be carried out under air and without inhibitors/stabilizers removal from the monomers/resins. However, efficient RISs are still based on peroxides or metal complexes. In this work, a pure organic and peroxide-free RIS is presented based on the interaction of a well-selected triarylamine derivative (T4epa) with iodonium salt used as reducing and oxidizing agents, respectively. The redox polymerization (Redox FRP) was followed through pyrometry and thermal imaging experiments. Remarkably, a full control of the work time as well as a high reactivity is observed for mild conditions.

A Review on Graphene’s Light Stabilizing Effects for Reduced Photodegradation of Polymers

Graphene, the newest member of the carbon’s family, has proven its efficiency in improving polymers’ resistance against photodegradation, even at low loadings equal to 1 wt% or lower. This protective role involves a multitude of complementary mechanisms associated with graphene’s unique geometry and chemistry. In this review, these mechanisms, taking place during both the initiation and propagation steps of photodegradation, are discussed concerning graphene and graphene derivatives, i.e., graphene oxide (GO) and reduced graphene oxide (rGO). In particular, graphene displays important UV absorption, free radical scavenging, and quenching capabilities thanks to the abundant π-bonds and sp2 carbon sites in its hexagonal lattice structure. The free radical scavenging effect is also partially linked with functional hydroxyl groups on the surface. However, the sp2 sites remain the predominant player, which makes graphene’s antioxidant effect potentially stronger than rGO and GO. Besides, UV screening and oxygen barriers are active protective mechanisms attributed to graphene’s high surface area and 2D geometry. Moreover, the way that graphene, as a nucleating agent, can improve the photostability of polymers, have been explored as well. These include the potential effect of graphene on increasing polymer’s glass transition temperature and crystallinity.

Carbon Nanomaterial-Based Nanofluids for Direct Thermal Solar Absorption

Recently, many scientists have been making remarkable efforts to enhance the efficiency of direct solar thermal absorption collectors that depends on working fluids. There are a number of heat transfer fluids being investigated and developed. Among these fluids, carbon nanomaterial-based nanofluids have become the candidates with the most potential by the heat absorbing and transfer properties of the carbon nanomaterials. This paper provides an overview of the current achievements in preparing and exploiting carbon nanomaterial-based nanofluids to direct thermal solar absorption. In addition, a brief discussion of challenges and recommendations for future work is presented.

High Performance Redox Initiating Systems Based on the Interaction of Silane with Metal Complexes: A Unique Platform for the Preparation of Composites

Currently, Redox Initiating Systems (RISs) of Free Radical Polymerization (FRP) are mainly based on the interaction of aromatic amines with peroxides (e.g., dibenzoyl peroxide (BPO)) that can be both toxic and unstable. In the present work, we aim to replace these hazardous substances in new RIS that can be peroxide-free and amine-free. Our redox two components (2K) initiating system is based on diphenylsilane (DPS) as reducing agent combined with different metal complexes (Mn(acac)₂, Cu(AAEMA)₂ or Fe(acac)₃) as oxidizing agents. For the new proposed RIS, an excellent reactivity is found for the polymerization of benchmark methacrylate monomers under mild conditions (redox polymerization done under air and at room temperature); remarkably, it is also possible to finely control the gel time. Different techniques (optical pyrometry, Real-Time FTIR spectroscopy, Cyclic Voltammetry and Electron Spin Resonance (ESR)) were used to follow the polymerization processes but also to shed some light on the new redox chemical mechanisms.

Harnessing the Day-Night Rhythm of Humidity and Sunlight into Mechanical Work Using Recyclable and Reprogrammable Soft Actuators

Toward a sustainable society, soft actuators driven by environmentally friendly energy from nature are of great social and economic significance. Meanwhile, recyclability, repeated reconfiguration for other use, and complex three-dimensional (3D) geometries are also essential for mitigating the energy crisis and practical application demands. Here, we integrate all of the above features in one actuator using vitrimers with exchangeable disulfide links. By reconfiguration, welding, patterning, and kirigami techniques, complex 3D actuators can be easily fabricated, which can be repeatedly reconfigured for other applications to save cost in new material preparation. These actuators operate synergistically with the day-night rhythm of humidity and sunlight without the need of extra energy input.

Coffee-based colloids for direct solar absorption

Despite their promising thermo-physical properties for direct solar absorption, carbon-based nanocolloids present some drawbacks, among which the unpleasant property of being potentially cytotoxic and harmful to the environment. In this work, a sustainable, stable and inexpensive colloid based on coffee is synthesized and its photo-thermal properties investigated. The proposed colloid consists of distilled water, Arabica coffee, glycerol and copper sulphate, which provide enhanced properties along with biocompatibility. The photo-thermal performance of the proposed fluid for direct solar absorption is analysed for different dilutions and compared with that of a traditional flat-plate collector. Tailor-made collectors, opportunely designed and realized via 3D-printing technique, were used for the experimental tests. The results obtained in field conditions, in good agreement with two different proposed models, show similar performance of the volumetric absorption using the proposed coffee-based colloids as compared to the classical systems based on a highly-absorbing surface. These results may encourage further investigations on simple, biocompatible and inexpensive colloids for direct solar absorption.

Biopolymer assisted synthesis of silica-carbon composite by spray drying

Spray drying had been used to synthesize silica-carbon black nanocomposite micrometric granules with a uniform distribution of the two components. This was achieved by hindering the preferential diffusion of hydrophobic carbon and hydrophilic silica particles in the water droplets during evaporative assembly by introducing gum arabic as a stabilizing agent and network former. Both positive and negatively charged silica nanoparticles were used to check the stability of the sol and its effect on the morphology of the spray dried granules. X-ray and neutron scattering, complemented with electron microscopy, were used to investigate the correlation and distribution of the nanoparticles within the granules. Porous silica granules, having surface area of 157 m²/g, were obtained after removal of carbon black by calcination. An environment-friendly solar absorbing coating had been prepared using as synthesized granules.

In6S7 nanoparticle-embedded and sulfur and nitrogen co-doped microporous carbons derived from In(tdc)2 metal-organic framework

Indium sulfide nanoparticle (NP)-embedded microporous carbons co-doped with S- and N-dopants are easily prepared by a direct carbonization of the as-prepared In(iii)-based metal-organic framework (In-MOF), [Et₂NH₂][In(tdc)₂]·DEF, containing ditopic S-containing 2,5-thiophenedicarboxylate (tdc^2-) bridging linkers as a potential source of S-dopant. The charge on the anionic framework of [In(tdc)₂]^- is balanced by Et₂NH₂⁺, which is also a potential N-dopant. Simultaneous embedding of In-based NPs, S-, and N-co-doping is achieved in a simple single step carbonization of In-MOF. Three porous carbon materials (PCMs), PCM-700, PCM-800, and PCM-900, are obtained from the carbonization of In-MOF at 700, 800, and 900 °C, respectively. The gas sorption analysis indicates them as good CO₂ sorbents. The photocatalytic degradation of methyl orange by PCMs under visible light irradiation is also effectively operable owing to the photocatalytically active semiconducting indium sulfide NP with a small bandgap. The main component of indium sulfide NPs is revealed as In₆S₇ based on the powder X-ray diffraction pattern. Small amounts of metallic In and In₂S₃ are also observed. The specific capacitances of PCMs are also estimated from the galvanostatic charge/discharge curves. PCM-900 exhibits the highest gravimetric specific capacitance of 99.0 F g^-1 at a current density of 0.05 A g^-1.

Carbon nanoparticles for solar disinfection of water

The present manuscript deals with the application of carbon nano particles (CNP) and chitosan (CHIT) in the form of CHIT-CNP composite for the disinfection of water. The CHIT-CNP composite was prepared by the solution casting method and characterized by TEM, XRD and elemental analysis. In the present investigation we study the disinfection efficiency towards E. coli bacteria of both CNP and CHIT-CNP, under sunlight (SODIS) in identical experimental conditions. Both CNP and CHIT-CNP enhanced disinfection as compared to SODIS alone, and comparable performance was achieved when the same dose of CNP in the two materials was applied. However, the CHIT-CNP composite is in the form of a fabric and it is easier to use and handle as compared to the CNP powder, especially in rural and resource-constrained areas. Moreover the SODIS-CHIT-CNP setup, when used in a compound parabolic collector (CPC) reactor showed high bactericidal efficiency compared to SODIS alone, which is promising for practical applications. The disinfection potential of the CNP powder was compared with that of the well-known material TiO₂ Degussa P25 (DP₂₅): DP₂₅ gave 6-log kill of bacteria in 180min, whereas CNP produced 6-log kill in 150min.

Nanofluid Types, Their Synthesis, Properties and Incorporation in Direct Solar Thermal Collectors: A Review

The global demand for energy is increasing and the detrimental consequences of rising greenhouse gas emissions, global warming and environmental degradation present major challenges. Solar energy offers a clean and viable renewable energy source with the potential to alleviate the detrimental consequences normally associated with fossil fuel-based energy generation. However, there are two inherent problems associated with conventional solar thermal energy conversion systems. The first involves low thermal conductivity values of heat transfer fluids, and the second involves the poor optical properties of many absorbers and their coating. Hence, there is an imperative need to improve both thermal and optical properties of current solar conversion systems. Direct solar thermal absorption collectors incorporating a nanofluid offers the opportunity to achieve significant improvements in both optical and thermal performance. Since nanofluids offer much greater heat absorbing and heat transfer properties compared to traditional working fluids. The review summarizes current research in this innovative field. It discusses direct solar absorber collectors and methods for improving their performance. This is followed by a discussion of the various types of nanofluids available and the synthesis techniques used to manufacture them. In closing, a brief discussion of nanofluid property modelling is also presented.

Photopolymerization processes of thick films and in shadow areas: a review for the access to composites

The state of the art for the access to thick samples by photopolymerization processes as well as some perspectives are provided.

Delivery of siRNA to ovarian cancer cells using laser-activated carbon nanoparticles

AIM

The RNAi-mediated knockdown of gene expression is an attractive tool for research and therapeutic purposes but its implementation is challenging. Here we report on a new method based on photoacoustic delivery of siRNA developed to address some of these challenges.

MATERIALS & METHODS

Physical properties and photoacoustic emission of carbon black (CB) particles upon near-infrared laser irradiation were characterized. Next, ovarian cancer cells Hey A8-F8 were exposed to near-infrared nanosecond laser pulses in the presence of siRNA targeting EGFR gene and CB particles. The intracellular delivery of siRNA and silencing of the target gene were determined by specific qPCR assays.

RESULTS & CONCLUSION

Laser-activated CB nanoparticles generated photoacoustic emission and enabled intracellular delivery of siRNA and significant knockdown of its target EGFR mRNA. This physical method represents a new promising approach to targeted therapeutic delivery of siRNA.

Hybridizing Poly(ε-caprolactone) and Plasmonic Titanium Nitride Nanoparticles for Broadband Photoresponsive Shape Memory Films

Plasmonic nanoparticles can confine light in nanoscale and locally heat the surrounding. Here we use titanium nitride (TiN) nanoparticles as broadband plasmonic light absorbers and synthesized a highly photoresponsive hybrid cross-linked polymer from shape memory polymer poly(ε-caprolactone) (PCL). The TiN-PCL hybrid is responsive to sunlight and the threshold irradiance was among the lowest when compared with other photoresponsive shape memory polymers studied previously. Sunlight heating with TiN NPs can be applied to other heat responsive smart polymers, thereby contributing to energy-saving smart polymers research for a sustainable society.