Simple Absorption Research Articles

Smart mathematically filtered UV spectroscopic methods for quality assurance of rosuvastatin and valsartan from formulation

Abstract Valsartan and rosuvastatin together in a binary form have been utilized to reduce hypertension and hyperlipidemia to control cardiovascular complications. This study depicts the simple three mathematically manipulated UV spectroscopic techniques for the estimation of rosuvastatin and valsartan in the formulation. The first method is simple UV absorption at 310 nm by RST and the first derivatization method for VTN. Determining the magnitude difference of a ratio spectrum at two identified wavelengths is the second approach, and determination of the magnitude of the first derivatives of the ratio spectra of RST and VTN constitute the third technique. The selection of wavelengths, divisor concentrations, and peak amplitudes were optimized and validated. The straight line was constructed in the range of 1–30 and 2–25 µg/ml for RST and VST by the normal and first derivatization method. By using the magnitude difference and magnitude of first derivative ratio spectra approaches, the concentrations of 1–12 and 2–25 µg/ml for RST and VTN, respectively, displayed a straight line. The limit of quantification was less than 1 µg/ml for RST and less than 2 µg/ml for VTN. It was eventually found that the accuracy, expressed as a percentage recovery, ranged between 98.94 and 99.55% for RST and 100.36 and 101.08% for VTN. The % RSD did not exceed 1.82 and 1.91 for RST and VTN, respectively. The three techniques were used to accurately measure RST and VTN in their binary formulations and physically mixed solutions, and the results were statistically compared to the previously published HPLC technique. The outstanding recovery achieved by using the authentic standard addition approach validated the methods’ supplemental accurateness. The Analytical Greenness and Red Green Blue procedures verified the eco-friendliness of the suggested UV spectroscopic approaches, which were also found to be superior to the documented HPLC methods.

A simple color absorption analysis of colorimetric loop-mediated isothermal amplification for detection of Raillietina spp. in clinical samples using a 3D-printed tube holder coupled with a smartphone camera and notebook screen.

Asimple method has been developedfor semi-quantitative analysis of the colorimetric output of loop-mediated isothermal amplification (LAMP) using a 3D-printed tube holder with a smartphone and notebook for the detection of Raillietina, which is the cause of Raillietiniasis affecting free-range chicken farming. In this method, a light is directedfrom a notebook screen to the LAMP products in the tube holder and the color absorption of the LAMP products is measured by using the appropriate smartphone application. It was found that the malachite green dye-coupled LAMP (MaG-LAMP) assay showed the highest sensitivity and specificity for detecting Raillietina without any cross-reaction with other related parasites and hosts. The limit of detection was 10fg/μL of DNA. A total of 60 fecal samples were infectively confirmed by microscopic examination and the results of microscopy compared with those of MaG-LAMP and triplex PCR assays. Microscopy and MaG-LAMP based on the color absorption demonstrated high agreement in Raillietina detection with kappa = 1. Rapid, simple, cost-effective, and easy interpretation of colorimetric LAMP assays and their high sensitivity make them superior to PCR and morphological investigation, demonstrating the feasibility of this assay in point-of-care screening to support farm management and solve chicken health problems. Our study presentsis an alternative diagnostic method using semi-quantitative analysis of colorimetric LAMP based on the differing solution color absorptions between positive and negative reactions for infectious disease diagnosis.

Effective electronic properties and coupling for two-temperature model-molecular dynamics simulation of ultrafast laser ablation of nickel

ABSTRACT The accuracy of hybrid two temperature model-molecular dynamics (TTM-MD) simulations in predicting the ultrafast laser ablation phenomena in metals is influenced by the functional definition of subsystem properties and electronic-lattice coupling. In this work, laser ablation of nickel is simulated using hybrid TTM-MD with empirical and density function theory (DFT) derived electronic and coupling parameter sets. The investigation revealed that the empirically derived temperature-dependent parameterisation of electronic specific heat, thermal conductivity, and coupling factor enhanced the fidelity of electron–phonon nonequilibrium dynamics when used in conjunction with simple optical absorption models, aligning closely with prior experimental observations for nickel specimens. The TTM-MD setup is then coupled utilising two widely used coupling techniques – the temperature difference scaled and Langevin thermostat. It is found that the former exhibits increased tensile stress due to artificial enhancement of the collision cascade owing to deterministic nature of the coupling force. While the probabilistic nature of the Langevin thermostat offers more accurate predictions of the ablation threshold/yield. Under these conditions, the TTM-MD scheme is tested for a range of absorbed laser fluence, with ablation threshold, and the onset of phase explosion is determined as 115 and 270 mJ/cm2, respectively for a 1 picosecond (ps-) laser pulse.

Water disinfection: Advances in photocatalysis and piezo/triboelectric catalysis with progressively enhanced energy utilization

AbstractIncreasing climate‐related extreme weather events and conflicts hinder safe water sanitation for vulnerable populations. In developing areas, centralized water systems are impractical due to high costs and poor infrastructure. Thus, technologies utilizing renewable energy like solar and mechanical energy for water treatment hold promise. It is critical to develop photocatalysts and piezoelectric/triboelectric catalysts that capture solar energy as well as mechanical energy to generate disinfectants to maximize energy utilization. The latest advancements in principles, materials, and processes utilizing solar and mechanical energy for water disinfection are highlighted in this review. First, we elucidate both direct and indirect mechanisms of sunlight‐mediated water disinfection, discuss the evolution of photocatalysts from simple UV absorption to visible‐light utilization, and even near‐infrared light exploitation to enhance solar spectrum utilization efficiency. Furthermore, we delve into the fundamental principles of piezoelectricity and triboelectricity relying on mechanical energy conversion as well as summarize the development of piezo/triboelectric catalysts from being driven by high‐frequency energy to utilizing low‐frequency mechanical energy from the environment. Finally, challenges and directions for efficient systems are outlined to inspire rational design strategies and accelerate the production of superior catalytic systems applicable across a broad range.

Energy, exergy, exergoeconomic, economic, and environmental analyses and multi-objective optimization of a novel combined cooling and power system with dual-pressure Kalina cycle-absorption refrigeration

A novel combined cooling and power system, the dual-pressure Kalina cycle-absorption refrigeration (DPKC-AR-CCP), is proposed for the cascade utilization of waste heat from high-temperature flue gas and jacket water from internal combustion engines. A pneumatic booster pump unit is employed to increase the inlet pressure of the low-pressure expander, with heat generated during the compression process utilized for preheating the ammonia/water mixture, and exhaust gas from the low-pressure expander is combined with driving gas for absorption refrigeration. By integrating the first and second laws of thermodynamics with the SPECO Methodology, models for energy, exergy, exergoeconomy, economy, and environment of the DPKC-AR-CCP system are developed. A multi-objective optimization model is formulated with maximum exergy efficiency, minimum total exergy cost rate, and maximum annual equivalent carbon dioxide (CO2) emission reduction as objective functions. MATLAB software (combined with REFPROP software) is utilized for simulation and multi-objective optimization. The performance of each component under specific conditions is assessed, and a comparison with the simple absorption refrigeration/Kalina cogeneration system (AR/KC) highlights the advantages of the DPKC-AR-CCP system; an investigation into the effects of different operating parameters on performance is conducted. The results indicate that, under identical operational parameters, the DPKC-AR-CCP system exhibits a substantial increase in net output power (230.2 %), cooling capacity (98.7 %), and exergy efficiency (148.8 %) compared to the simple AR/KC system; payback period is reduced by 64.8 %; and annual equivalent CO2 emissions are decreased by 202.2 %. However, there is an increase in the total exergy cost rate by 90.5 %. The optimal concentration of ammonia/water is determined to be 0.816/0.184, with a heat exchanger outlet temperature of 341.07 K, driving pressure of 0.654 MPa, and low-pressure expander inlet pressure of 5.064 MPa. Correspondingly, the optimal exergy efficiency is 87.2 %, the annual reduction in CO2 emissions is 5.53 × 107 kg, and the total exergy cost rate is 288.48$/h.

Feasibility and Application of Local Closed-Loop Materials to Produce Compressed and Stabilized Earth Blocks.

The validation of a feasible application for the production of sustainable bricks with local materials in humid and hot climates, which would allow the current housing needs of a constantly growing population with scarce economic resources to be met while also reducing energy inputs for climate control, is a current challenge without a definitive solution. Therefore, this research studied the incorporation of local aggregates and two second-generation materials to produce lime-stabilized Compressed Earth Blocks (CSEBs) using a semi-automatic machine for their manufacture. An initial matrix was designed as a baseline, and three more were developed with variations to incorporate second-generation materials individually and as mixtures. The stabilizer was added in concentrations of 5, 10, and 15%, resulting in a total of 12 batches of CSEBs. Eleven of the studied batches exceed the normative limits for simple compressive strength and initial water absorption coefficient. The best result of simple compressive strength was obtained in two batches of the same matrix that used construction demolition waste (CDW), reaching 4.3 MPa (43% above the minimum limit established by the most restrictive regulations and 115% above the least restrictive). It was possible to produce sustainable bricks in situ with average ambient temperatures of 32 °C and relative humidity of 91%.

Study on the Thermal Stability of Molybdenum Oxide‐Passivated Silicon Solar Cells

Dopant‐free heterojunction (HJ) solar cells are known for their simple process conditions and low parasitic absorption. However, stability issues remain one of the major obstacles for further development of cells with transition metal oxides (TMOs). Therefore, this research demonstrates the mechanism of thermal annealing degradation effects on TMOs/silicon (Si) HJ, namely, the infiltration of oxygen from air and the bidirectional diffusion of oxygen from TMOs, by investigating a typical molybdenum oxide (MoOx)/Si contact. A dense Au interlayer is introduced to block the interdiffusion of oxygen from the MoOx/Si interface and its surrounding environment. As a result, the dense layer slows down the interfacial oxidation of MoOx/Si and the degradation of the MoOx work function, thus improving the stability of the MoOx/Si HJ to 200 °C. The diffusion of oxygen from MoOx to the MoOx/Si interface will be critical to further promote the thermal stability of the devices thereafter, especially for the cells with i‐a‐Si:H layer as the passivation layer. To attain stable dopant‐free cells with MoOx, it is crucial to prevent oxygen diffusion into Si while maintaining a high MoOx work function and a thin SiOx layer at the interface.

STRENGTH DEVELOPMENT IN CLAY-STABILIZED BRICKS WITH CEMENT AND RICE BY-PRODUCTS

Bricks, traditionally used in the construction sector, use high energy and generate significant emissions of CO2 in their production process. As a result, as a lower-impact and low-cost alternative, this study analyzed different types of mixtures of soil, cement, rice husk, and rice husk ash to decrease the amount of cement, which was substituted gradually with rice husk and rice husk ash, to stabilize and improve the characteristics of clay, and to compare the effectiveness of earth stabilized bricks respect to traditional bricks. The research was carried out in three phases which were soil-cement, soil-cement-rice husk ash, and soil-cement-rice husk ash-rice husk, from which we concluded the best mixture consists in low-plasticity clay soil (CL), 14% Portland cement, 6% rice husk ash, and 4% rice husk, which in the simple compressive strength after 7 days of curing is not affected by the decrease in cement but increases by 0.41 MPa, which in addition shows better results in simple compression, absorption, and flexure tests than traditional bricks.

A graphene-based THz selective absorber with absorptivity 95 % and wide-range electrical tunability

A growing adoption of Terahertz (THz) frequency across various applications is witnessed in the recent years. This specific frequency range is said to yield a breakthrough in high-speed electronics and communications, besides its significant role in the medical field regarding scanning and treatment. As frequency absorbers are one of the common blocks in the mentioned applications, they were the focus of many research work. In this paper, we present a theoretical model for a selective THz frequency absorber that has more than 90 % absorptivity and can reach 95 % and near unity absorptivity at some frequencies. The structure is based on monolayers of nanoribbons of graphene, MoS2, and phosphorene. The utilization of the surface plasmon oscillations of these two-dimensional (2D) materials, in addition to the impedance matching, is employed to achieve maximum absorptivity. The structure has an electrically tunable selective frequency from 1.3 THz to 10 THz that nearly covers the whole THz range, and a bandwidth ranging from 0.9 THz to 1.3 THz. Electrical tunability is done through varying the applied voltage on the MoS2/graphene heterostructure (0.2 V ∼ 5 V) based on the tunable conductivity of graphene. In addition to the voltage tunability of the design, the absorption frequency is also swept by varying the nanoribbons widths (20 nm ∼ 160 nm). The proposed design surpasses previous ones by its simple structure and high absorption through the entire THz range, besides its low cost of fabrication. The structure is ultrathin (∼10 nm) that it can fit in ultrathin electronics. It has a relatively small bandwidth compared to previous work, that represents the basis for narrowband absorbers. The structure is simulated using the finite element method (FEM) and verified using the transmission line circuit theory which demonstrated the validity of the structure for higher frequency ranges. The possibility of future synthesis is also discussed.

Understanding Nucleophilicity of Pyridine-N-oxides Towards 2,4,6-Trinitrophenylbenzoate Through Simple Absorption Spectroscopic Studies

Aims: Understanding nucleophilicity of poor nucleophiles like pyridine-N-oxides. Background: Nucleophilicity plays a vital role in substitution reactions. It helps to determine the possibility and extent of the substitution reactions. The study of the nucleophilicity of poor nucleophiles is challenging, and it has limited substrate scope. Understanding the strength of nucleophilicity of such poor nucleophiles in a quantitative way is important. Objective: Understanding the strength of nucleophilicity of such poor nucleophiles in a quantitative way. Selection of appropriate electrophile for the reactions with the poor nucleophiles-pyridine-N-oxides. Development of suitable methodology for kinetic studies of the reaction. Methods: UV-Vis spectroscopic methods for monitoring the reactions. Results: The kinetic studies revealed that the second-order rate constants of the nucleophilic reactions are 1.67× 102 L mol-1 min-1, 29.8 L mol-1 min-1, 29.51 L mol-1 min-1, where the nucleophiles are p-methylpyridine-N-oxide, pyridine-N-oxide, and p-nitropyridine-N-oxide, respectively. The UV-Vis spectroscopic analysis revealed the nucleophilicity of p-methylpyridine-N-oxide > pyri-dine-N-oxide > p-nitropyridine-N-oxide. Conclusion: This comparative study suggests that the strength of nucleophilicity of the p-methylpyridine-N-oxide is 5.6 times and 66.53 times more than that of pyridine-N-oxide and p-nitropyridine-N-oxide, respectively, whereas the strength of nucleophilicity of the pyridine-N-oxide is 11.87 times more than that of p-nitropyridine-N-oxide.

Methylene Blue absorption By Coffee Waste Activated Carbon

Textile industries are one of the major contributors to the environmental pollution problems in the world. Textile industries release many dyes and various contaminants at a variety of ranges. Wastewater needs to be treated before being released into the environment to prevent bad effects on humans and living things. These studies describe how coffee waste activated carbon removes methylene blue dye from wastewater in cost effective way by using coffee waste via a simple absorption method. Coffee waste activated carbon (CWAC) was produced by carbonization and followed by chemical activation using 1M potassium hydroxide (KOH) and physical activation by a furnace for 850° C for 2 hours. The absorption test was erformed with 0.1 g to 0.9 g of CWAC in 100 ml of 500 ppm methylene blue and the samples were taken every 10 minutes. The absorption of dye by CWAC was assessed by using UV-Viss Spectrophotometer. As a result, the coffee waste is possible to treat dyes up to 80 % in a short time. In 10 minutes, 0.1g of AC can remove dyes as much as 79.1%.

Measurement of the Adhesion Force of a Living Sessile Organism on Antifouling Coating Surfaces Prepared with Polysulfobetaine-Grafted Particles.

An antifouling polymer brush-like structure was fabricated by a simple and versatile dip-coating method of sulfobetaine containing copolymer-grafted silica nanoparticles (SiNPs) and alkyl diiodide cross-linkers. Surface-initiated atom transfer radical copolymerization of 3-(N-2-methacryloyloxyethyl-N,N-dimethyl)ammonatopropanesulfonate (MAPS) and N,N-dimethylaminoethyl methacrylate (DMAEMA) was carried out from initiator-immobilized SiNPs to give poly(MAPS-co-DMAEMA)-grafted SiNPs (MAPS/DMAEMA = 9/1, mol/mol) with diameters of 150-170 nm. The SiNP-g-copolymer/2,2,2-trifluoroethanol solution was dip-coated on silicon and glass substrates. Successive treatment with 1,4-diiodobutane in methanol gave a hydrophilic cross-linked coating film for the SiNP-g-copolymer. The cross-linked particle brushes did not peel off from the substrate even after washing with water in an ultrasonic cleaner despite the simple physical absorption of the SiNP-g-copolymer on the substrate surface. The adhesion force of the tentacle of a living barnacle cyprid on a glass surface covered with the cross-linked SiNP-g-copolymer was directly measured by scanning probe microscopy in seawater. The coating film exhibited extremely low adhesion to the cypris larva in the seawater, expecting this to be an effective antifouling property.

Exploring marine collagen: Sustainable sourcing, extraction methods, and cosmetic applications

The predominant sources of collagen for cosmetic purposes were traditionally derived from bovine and porcine products, such as bones, tendons, and connective tissues. However, these sources are gradually declining in popularity due to their restricted availability, religious constraints, and disease-related concerns. Consequently, there is an urgent necessity to explore alternative sustainable collagen sources. Marine species offer a promising and sustainable supply for alternative collagen sources due to lower risk of disease transmission, freedom from religious restrictions, biocompatibility, lower molecular weight, lower production costs, and simpler absorption by the human body. This study objective highlights to explore potential collagen sources from marine resources (fishes, poriferans, mollusks, crustaceans, echinoderms, and coelenterates) for cosmetic applications. A variety of marine collagen sources with different extraction techniques will be compared. The study finds that fish by-products, particularly skins and bones, are becoming a very encouraging sustainable collagen source contrasted with other alternatives. They exhibit a significant collagen content, comprising up to 61.26 % of their dry weight under acid-soluble collagen (ASC) extraction method. Fish skin and bone-derived collagen is mostly composed of type I collagen and has been proven to possess notable capabilities as an antioxidant, antiaging, and skin-whitening agent. Therefore, the utilization of marine collagen as a key ingredient in cosmetics promotes responsible sourcing, encourages eco-friendly practices, and fosters a circular economy by making the most of underutilized marine materials.

Comparison between two LiBr–H2O absorption-compression chillers and a simple absorption chiller driven by various solar collectors: Exergy-economic performance and optimization

Although some studies have been conducted on various types of compressor-based absorption chillers (ACH), a comprehensive comparison of the performances of these configurations has not been made. In addition, selecting a proper solar collector in combination with the best compressor-based ACH is worthwhile as solar energy is widely available during the summer season. For this purpose, the exergy-economic performances of 12 LiBr–H2O chiller configurations are compared in the present study to produce 100 kW of cooling. The configurations are a single-effect ACH and two absorption-compression chillers (ACCH) driven by 4 collector types, namely, a flat plate collector (FPC), an evacuated tube collector (ETC), a parabolic trough collector (PTC), and a compound parabolic collector (CPC). In ACCH 1, a compressor is embedded between the evaporator and the absorber of the ACH. In ACCH 2, a compressor is employed between the generator and the condenser of the ACH. The outcomes of the research indicate the superiority of the PTC and ETC over the two other collector types in terms of exergy efficiency and economic performance, respectively. The highest exergy efficiency and lowest total cost rate are calculated as 4.8% and 23.58 $h−1, which are obtained by the PTC-driven ACCH 1 and ETC-driven ACCH 1, respectively. Nevertheless, the unit cost of cooling produced by these two layouts is too high compared to the other configurations. Hence, they cannot be selected as the best configuration. Instead, the ETC-driven ACCH 2 is selected as the best configuration since it brings about the lowest unit cost of cooling (20.45 $GJ−1), and it has acceptable values of exergy efficiency (4.11%) and total cost rate (29.3 $h−1).

Extraction and Optical Study of Natural Dyes for Dye-Sensitized Solar Cell Application

Extraction and study of the optical properties of natural dyes from several plant parts such as leaves, flowers, tubers, and fruits have been carried out using a simple maceration method and UV-Vis absorption characterization. The samples were divided into several groups in this study, namely the flower group (Tagetes sp., Paeonia sp., Centaure sp., Chrysanthemum sp., Carthamus tinctorius, Gomphrena globosa, Myosotis sylvatica, Lavandula sp., Clitoria ternatea, Matricaria chamomilla, Hibiscus sabdariffa, and Rosa sp.); the leaf group (Mangifera indica, Moringa oleifera, Graptophyllum pictum, Spinacia oleracea, Citrus hystrix, and Terminalia sp.); and the tuber and fruit group (Solanum lycopersicum, Cucurbita moschata, Garcinia mangostana, Curcuma longa, Beta vulgaris, and Caessapina sp.). The extract of natural dyes was successfully produced using a low-cost and simple extraction approach via dehydration, immersion for 2×24 hours in ethanol, and followed by filtration. The optical properties of the dyes in UV and visible light range were observed using a UV-Vis spectrophotometer in the wavelength of 400-700 nm. The absorption behaviour showed dominant peaks at different wavelengths for each group. Potentially, to do a combination of dyes (co-sensitization: using more than a dye with different absorption spectra to achieve a panchromatic response) to widen the wavelength absorption for dye-sensitized solar cell (DSSC) applications.

Multi-channel Deep-UV absorbance measurement setup for multi-capillary electrophoresis with two fiber arrays facing each other

We have developed a simple, compact, and robust eight-channel ultraviolet (UV) absorption detection setup featuring two eight-fiber arrays (an irradiation fiber array and a detection fiber array) whose ends face each other across eight capillaries. UV light of a 220-nm wavelength from a single deuterium lamp is stably and evenly split into eight lights by using a thick homogenizing fiber connected to a fiber bundle with eight thin fibers, which make up the irradiation fiber array. Each capillary is directly irradiated with each UV light emitted from the irradiation fiber array and then each of the UV lights transmitted through the capillaries is collected by each fiber of the detection fiber array without using any other optical devices (e.g., a lens) and is detected by each of the eight photodetectors. This setup achieves simultaneous UV absorption measurement for all eight capillaries with the detection limit of 54 μAU, linear dynamic range of four logs or more, and negligible crosstalk of 0.01% or less. We also implemented an eight-capillary electrophoresis system and simultaneously analyzed eight immunoglobulin G samples, separated by capillary electrophoresis sodium dodecyl sulfate.

Preparation and Thermal Properties of Propyl Palmitate-Based Phase Change Composites with Enhanced Thermal Conductivity for Thermal Energy Storage.

Phase change materials (PCMs), which can absorb and release large amounts of latent heat during phase change, have been extensively studied for heat storage and thermal management. However, technical bottlenecks regarding low thermal conductivity and leakage have hindered practical applications of PCMs. In this paper, a simple, economical, and scalable absorption polymerization technique is proposed to prepare the polymethyl methacrylate/propyl palmitate/expanded graphite (MPCM/EG) phase change composites by constructing the microencapsulated phase change materials (polymethyl methacrylate/propyl palmitate, MPCM) with core-shell structures in the three-dimensional (3D) EG networks, taking propyl palmitate as the PCM core, polymethyl methacrylate (PMMA) as the shell, and long-chain "worm-like" EG as the thermally conductive networks. This technique proved to be a more appropriate combinatorial pathway than direct absorption of MPCM via EG. The MPCM/EG composites with high thermal conductivity, high enthalpy, excellent thermal stability, low leakage, and good thermal cycle reliability were prepared. The results showed that the MPCM-80/EG-10 composite demonstrated a high thermal conductivity of 3.38 W/(m·K), a phase change enthalpy up to 152.0 J/g, an encapsulation ratio of 90.3%, outstanding thermal stability performance, and long-term thermal cycle reliability when the EG loading is 10% and propyl palmitate is 80%. This research offers an easy and efficient approach for designing and fabricating phase change composites with promising applications in diverse energy-saving fields, such as renewable energy collection, building energy conservation, and microelectronic devices thermal protection.

High-efficiency and all-weather crude oil spill remediation by an eco-friendly self-heating MXene-coated poly(butylene adipate-co-terephthalate) porous monolith

Frequent oil spill incidents have resulted in serious environmental pollution posing a great threat to human health and ecological system, thus developing new absorbents to efficiently remove and recycle high-viscosity crude oil is attracting more attention. We herein report an eco-friendly flexible poly(butylene adipate-co-terephthalate) (PBAT)-based monolith with MXene (Ti3C2Tx) and polydimethylsiloxane (PDMS) coatings (P-MXene@PBAT monolith) by convenient and economical preparation method for self-heating driven fast crude oil cleanup. Due to unique three-dimensional interconnected pore structure and superior hydrophobicity, the P-MXene@PBAT showed high saturated absorption capacity and cyclic separation efficiency for multifarious low-viscosity oils. The P-MXene@PBAT was endowed with excellent photo/electro-thermal performance via wrapping MXene layer. The maximum surface temperature of monolith quickly reached up to 81 °C under 1.0 kW m−2 (1.0 sun) irradiation and 91 °C under 8 V voltage, respectively. Furthermore, the P-MXene@PBAT could self-heat crude oil to dramatically decrease oil viscosity and accelerate separation process. Specially, the P-MXene@PBAT was able to continuously separate crude oil from water with a simple pump-assisted absorption device (crude oil flux of 204 kg m−2 h−1), which adapted to varied working conditions by coupling solar heating and Joule heating. Such environmental-friendly all-weather absorbent design provides a sustainable strategy for efficient remediation of crude oil spill.

Estimators of tissue absorption parameters power-law prefactor and power-law exponent from medical ultrasonic images

Abstract Ultrasound is a mechanical wave propagating in tissue which is influenced in its propagation behavior by the locally prevailing acousto-mechanical conditions. By suitable processing of the back-scattered signals received by the ultrasound transducer, tissue parameters such as local bulk modulus, mass density, speed of sound, isotropic scattering coefficient, and also the locally acting tissue absorption can be inferred. A discipline that has received increasing attention in the medical ultrasonic imaging discipline and its scientific publications in recent years is quantitative ultrasound (QUS) which tries to estimate with great accuracy these local acting tissue parameters. In this paper we analyze different algorithms for estimation of high spatial resolution tissue absorption parameters. On the one hand, there is a simple absorption estimator based on the evaluation of the quotient of the power density spectra calculated for different depth regions (spectral-log-difference estimator), which, however, assumes a linearly with frequency increasing absorption, this is contrasted with an estimator which also allows to estimate a polynomial increase of the absorption with frequency (method-of-moments estimator). Since a closed-form solution cannot be given for this, a maximum-likelihood estimator for which there is always an estimate that can be computed numerically efficiently is developed. The results, tissue attenuation, are presented as a color-coded overlay on conventional B-mode ultrasound images showing only morphology.

Development of a cooling and power generation prototype integrating an axial micro-turbine in an absorption chiller

The integration of an expander in an absorption machine allows it to produce cooling and electricity simultaneously within the same cycle. This technology holds great potential to harness low-temperature heat sources more efficiently than production with separate cycles. However, very few experimental studies on absorption combined cooling and power production cycles can be found in literature. In order to achieve an in-depth understanding of this technology and of the interactions between power and cooling production sides of the circuit, the integration of an expander into a single stage ammonia water absorption chiller was undertaken through the development of an experimental pilot plant. The peculiar characteristics of the expansion device, as well as the use of a newly developed combined desorber avoiding the presence of a rectifier make the prototype built unique. Design and integration of the expander proved to be very challenging, mainly due to the small size of the application and corrosiveness of the ammonia water mixture. Significant electricity generation losses experienced lead to maximum electrical efficiency of 7% and corresponding maximum power production around 33 W at a lower than expected rotational speed of 20′000 rpm.Despite these difficulties, first experimental measurements have been obtained, giving interesting insights on the functioning of the cycle. Indeed, the impracticability of regulating the ratio between cooling and power production was highlighted, due to the characteristics of the impulse turbine. Opening of the turbine line in the nominal point leads to a reduction of the mass flow rate passing through the cooling line of 65% (i.e., split ratio of 0.35) and a cooling power output decrease of around 57% (from 4.9 to 2.1 kW). Additionally, diverting some of the desorbed vapour to the power production line has important effects on the pressure equilibrium and circulating vapour mass flow rate, increasing from 16.1 kg/h in the simple absorption working mode to 31.1 kg/h in the combined mode in the nominal operating point. Feedback from the pilot plant will be very useful for the further development of the technology.