Carrier Capacity Research Articles

Oxygen-Induced Elemental Mercury Oxidation in Chemical Looping Combustion of Coal.

Mercury emission is an important issue during chemical looping combustion (CLC) of coal. The aim of this work is to explore the effects of different flue gas components (e.g., HCl, NO, SO2, and CO2) on mercury transformation in the flue gas cooling process. A two-stage simulation method is used to reveal the reaction mechanism of these gases affecting elemental mercury (Hg0) oxidation. Furthermore, using this method, Hg0 oxidation by eight oxygen carriers (Co3O4, CaSO4, CeO2, Fe2O3, Al2O3, Mn2O3, SiO2, and CuO) commonly used in CLC are investigated and their Hg0 oxidation efficiencies were compared with the existing experimental results. The results show that HCl, NO, and CO2 promote Hg0 oxidation during flue gas cooling, while SO2 inhibits Hg0 oxidation. The stronger the oxygen release capacity of oxygen carriers, the higher the oxidation efficiency of Hg0 becomes. The order of Hg0 removal efficiency from high to low is Co3O4, CuO, Mn2O3, CaSO4, Fe2O3, CeO2, Al2O3, and SiO2, and this sequence is in good agreement with the existing experimental results. Different flue gas components directly or indirectly affect the O2 content, thus affecting the content of gaseous oxidized mercury (Hg2+). Different oxygen carriers have different oxygen release capacities and different Hg0 oxidation efficiencies. Therefore, O2 is the core species affecting the mercury transformation in CLC.

Fabrication of InGaZnO-SnO2/PCBM hybrid electron transfer layer for high-performance Perovskite solar cell and X-ray detector

We developed heterojunction electron-transfer layers (ETLs) comprising layers of metal oxides and phenyl-C71-butyric acid methyl ester (PCBM) for use in glass/indium tin oxide/hole transport layer/Perovskite/ETL/LiF/Al solar cells and X-ray detectors. Indium gallium zinc oxide (IGZO), tin oxide (SnO2), or IGZO/SnO2 layers were stacked on a PCBM layer via radio frequency (RF) magnetron sputtering at various temperatures. The formation of the metal-oxide layers and on a PCBM film were confirmed by conducting compositional and elemental mapping studies. Current-voltage experimental results show that the heterojunction fabricated by forming a IGZO/SnO2 layer on a PCBM film possessed higher charge carrier capacity and exciton dissociation properties compared with using either IGZO or SnO2 separately. The Perovskite solar cell with an IGZO/SnO2@100/PCBM (100 refers 100oC of RF sputtering temperature) ETL attained a power conversion efficiency (PCE) of 12.56 ± 0.15%, which was 36% more efficient than a device with a pure PCBM ETL (PCE = 9.22 ± 0.09%). Moreover, an X-ray detector fabricated with an IGZO/SnO2@100/PCBM ETL obtained a maximum sensitivity of 3.98 mA/Gy·cm2 and collected charge density (CCD)-dark current density (DCD) of 13.29 μA/cm2.

Experimental investigation of biofilm carriers of varying shapes, sizes, and materials for wastewater treatment in fixed bed biofilm reactor: a qualitative study of biocarrier performance

AbstractBACKGROUNDBiofilm carriers were introduced in the early 1990s mainly to abate chemical oxygen demand (COD). However, studies have continued investigating few biocarriers repeatedly, without studying a large number of carriers in a single study under similar conditions.RESULTSThe current study investigated the performance of nine synthetic and eight natural biofilm carriers for 7 days of palm oil mill effluent (POME) treatment in terms of COD removal. A fixed bed biofilm reactor (FBBR) was 100% packed with biocarriers and operated at 35 °C. Performance based on the 7th day COD removal could be ranked in the following order: green ammonia absorption stone (91%), K1 micro (88%), coral sand (87.8%), volcanic stone (86.6%), Micro Media (85.5%), 1.6 cm BioBall (85%), pebble (82.4%), porous ceramic ring (82.3), K1 (82.1%), non‐porous ceramic ring (80.9%), brown ammonia absorption stone (78.6%), biological filter (77.7%), Ultra Media (76.8%), blue media (69.3%), 3.0 cm BioBall (68.8%), 2.5 cm BioBall (66.5%), and loofah sponge (63%).CONCLUSIONThe smallest carrier, K1 micro, yielded the highest COD removal (88%) on day 7 among the other synthetic carriers, while green ammonia absorption stones provided the highest quality effluent from day 1 (3565 mg COD L−1) to day 7 (780 mg COD L−1) and delivered the shortest start‐up compared with all natural and synthetic carriers. The discussion revealed that all carrier functionalities (i.e., scale, shape, surface pores, roughness, material, surface area, porosity, and durability) play a key role in deciding carrier quality. The current study also introduced ‘carrier efficiency limit’, which refers to the carrier's capacity to entrap biomass and immobilize microorganisms. © 2022 Society of Chemical Industry (SCI).

Dicarboxylated hyaluronate: Synthesis of a new, highly functionalized and biocompatible derivative

Sequential periodate-chlorite oxidation of sodium hyaluronate to 2,3-dicarboxylated hyaluronate (DCH), a novel biocompatible and highly functionalized derivative bearing additional pair of COOH groups at C2 and C3 carbons of oxidized ᴅ-glucuronic acid units, is investigated. The impact of various reaction parameters (time, oxidizer concentration, and molar amount) on DCH's composition, molecular weight, degree of oxidation, and cytotoxicity are investigated to guide the synthesis of DCH derivatives of desired properties. Subsequently, fully (99%) and partially (70%) oxidized DCH derivatives were compared to untreated sodium hyaluronate in terms of anticancer drug cisplatin loading efficacy, carrier capacity, drug release rates, and cytotoxicity towards healthy and cancerous cell lines. DCH derivatives were found to be superior in every aspect, having nearly twice the carrier capacity, significantly slower release rates, and higher efficacy. DCH is thus a highly interesting hyaluronate derivative with an adjustable degree of oxidation, molecular weight, and great potential for further modifications.

Influence of an Oxygen Carrier on the CH4 Reforming Reaction Linked to the Biomass Chemical Looping Gasification Process.

A major challenge in biomass chemical looping gasification (BCLG) is the conversion of CH4 and light hydrocarbons to syngas (CO + H2) when the goal is the use for bioliquid fuel production. In this work, tests were performed in a batch fluidized bed reactor to determine the catalytic effect on the CH4 reforming reaction of oxygen carriers used in the BCLG process. Three ores (ilmenite, MnGB, and Tierga), one waste (LD slag), and five synthetic materials (Fe10Al, Fe20Al, Fe25Al, Cu14Al, and Ni18Al) were analyzed. These results were compared to those obtained during ∼300 h of continuous biomass gasification operation in a 1.5 kWth BCLG unit. The low-cost materials (ores and waste) did not show any catalytic effect in the CH4 reforming reaction, and as a consequence, the CH4 concentration values measured in the syngas produced in the continuous prototype were high. The synthetic oxygen carriers showed a catalytic effect in the CH4 reforming reaction, increasing this effect with increasing temperature. With the exception of the Ni-based oxygen carrier (used as a reference), the Cu-based oxygen carrier, working at 940 °C, showed the best catalytic properties, in good agreement with the low CH4 concentration values measured in the syngas generated in the continuous unit. The tests performed in a batch fluidized bed reactor were demonstrated to be very useful in determining the catalytic capacity of oxygen carriers in the CH4 reforming reaction. This fact is highly relevant when a syngas with a low CH4 content is desired as a final product.

Breaking the Stoichiometric Limit in Oxygen-Carrying Capacity of Fe-Based Oxygen Carriers for Chemical Looping Combustion using the Mg-Fe-O Solid Solution System

Breaking the Stoichiometric Limit in Oxygen-Carrying Capacity of Fe-Based Oxygen Carriers for Chemical Looping Combustion using the Mg-Fe-O Solid Solution System

Zwitterionic polymer-mediated immobilization of organophosphorus hydrolase enhances hydrolysis of methyl parathion by substrate enrichment

Organophosphorus pesticides (OPPs) degradation is highly demanded due to the toxic nature of the pesticides that have caused serious environmental concerns. Biocatalytic hydrolysis using organophosphorus hydrolase (OPH) is an important way to OPPs degradation, but the poor stability of OPH severely hindered its extensive applications in environmental bioremediation. It is well known that immobilization is an efficient way of enzyme stabilization, so this work has proposed to immobilize OPH onto mesoporous silica nanoparticles coated with a zwitterionic polymer containing short hydrophobic chains. It is found that the zwitterionic polymer coating significantly modified the microenvironment, leading to the stabilization of the immobilized enzyme while keeping its activity toward methyl parathion hydrolysis. More importantly, the coating resulted in the substrate enrichment onto the carrier (capacity, 49.7 mmol·g−1; dissociation constant, 11.7 μM), so the immobilized OPH presented a much lower Michaelis constant (0.09 mM) than its free counterpart (0.34 mM) as revealed by kinetic studies. Consequently, the catalytic efficiency (kcat/Km) of the immobilized OPH was 2.41 times higher than free OPH. Thus, this work demonstrated the promise of the zwitterionic polymer-mediated immobilization strategy for OPH in enhancing the enzyme performance for the hydrolysis of OPPs that are of low concentration in open environments.

Defect engineering in novel broad-band gap hexaaluminate MAl12O19 (M=Ca, sr, Ba)-Based photocatalysts Boosts Near ultraviolet and visible light-driven photocatalytic performance

The M(M = Ca, Sr, Ba)Al12O19, MAl12O19:Mn, and MAl12O19:Mn:Ce photocatalysts have been synthesized successfully through a polyacrylamide gel method. The Mn ion prefer to occupy the position of Al ion in SrAl12O19, while there is no evidence revealing that the Mn ion occupies the Al ion position in (Ca, Ba)Al12O19. The one-pot polyacrylamide gel method utilizes the fast nucleation, growth, and heterostructure construction of the MAl12O19 to deliberately immobilize the desired fine spherical particles of Mn3O4 or Mn3O4 and CeO2 on the surface of MAl12O19 nanosheets. All the MAl12O19:Mn:Ce photocatalysts exhibited outstanding photocatalytic activities for the degradation of methylene blue than that of M(M = Ca, Sr, Ba)Al12O19 and MAl12O19:Mn photocatalysts under near ultraviolet and visible light irradiation. The improved photocatalytic activity of n-p-n type double p-n heterojunction MAl12O19:Mn:Ce photocatalysts can be attributed to the synergistic effect among the M(M = Ca, Sr, Ba)Al12O19, CeO2, and Mn3O4, which not only improves the visible light response ability and enhances the migration and separation efficiency of charge carriers but also retains the strong the oxidation or reduction capacity of charge carriers. This work may provide a n-p-n type double p-n heterojunction photocatalytic system into the development and design high efficient heterojunction photocatalysts for the degradation of organic dyes and environmental protection.

Two-Dimensional Ultra-Thin Nanosheets with Extraordinarily High Drug Loading and Long Blood Circulation for Cancer Therapy.

Nanoparticle drug delivery is largely restricted by the low drug loading capacity of nanoparticle carriers. To address this critical challenge and maximize the potential of nanoparticle drug delivery, a 2D ultra-thin layered double hydroxide (LDH) nanosheet with exceptionally high drug loading, excellent colloidal stability, and prolonged blood circulation for cancer treatment is constructed. The nanosheet is synthesized via a biocompatible polymer-assisted bottom-up method and exhibits an ultra-thin 2D sheet-like structure that enables a considerable amount of cargo anchoring sites available for drug loading, leading to an extraordinary 734% (doxorubicin/nanoparticle mass ratio) drug loading capacity. Doxorubicin delivered by the nanosheet remains stable on the nanosheet carrier under the physiological pH condition, while showing sustained release in the tumor microenvironment and the intracellular environment, thus demonstrating on-demand drug release as a result of pH-responsive biodegradation of nanosheets. Using in vitro and in vivo 4T1 breast cancer models, the nanosheet-based ultra-high drug-loading system demonstrates even enhanced therapeutic performance compared to the multilayered LDH-based high drug-loading system, in terms of increased cellular uptake efficiency, prolonged blood circulation, superior therapeutic effect, and reduced systemic toxicity.

Printed asymmetric microcapsules: Facile loading and multiple stimuli-responsiveness.

Engineering of colloidal particles and capsules despite substantial progress is still facing a number of unsolved issues including low loading capacity, non-uniform size and shape of carriers, tailoring different functionalities and versatility to encapsulated cargo. In this work, we propose a method for defined-shaped functionally asymmetric polymer capsule fabrication based on a soft lithography approach. The developed capsules consist of two classes of polymers - the main part "cup" is made out of polyelectrolyte multilayers (PAH-PSS) and "lid" is made of biodegradable polyether (PLGA). Asymmetric capsules combine advantages from both traditional layer-by-layer capsules and recently developed printed "pelmeni" capsules. This combination provides stimuli-responsiveness due to polyelectrolyte multilayer properties differing from PLGA. The inner volume of capsules can be loaded with a variety of active compounds and the capsule's geometry is defined due to the soft-lithography method. Capsules have a core-shell structure and monodisperse size distribution. Three methods to trigger cargo release have been demonstrated, namely temperature treatment, ultrasonication and pH shift. Steroidal drug dexamethasone was used to illustrate the applicability of the systems for triggered drug release. The application of proposed asymmetric capsules includes but is not limited to pharmacology, diagnostics, sensors, micro- and nanoreactors and chemical actuators.

Brewer’s Spent Dry Yeast Modulates Immunity in Gilthead Sea Bream (Sparus aurata)

In this study, we evaluated the replacement of dietary protein sources like fishmeal (FM) and plant proteins (PP) by Brewer’s spent dry yeast (SDY) on the transcriptomic response (RNA-seq, NextSeq500 platform Illumina) in the liver, anterior-mid intestine, and head kidney in juveniles of gilthead sea bream (Sparus aurata). The inclusion of SDY at 30% in the experimental diet (40% crude protein, 16% crude lipid) resulted in a reduction in FM (10%) and PP (31.4%) contents. Using RNA-seq, a total of 19.4 million raw reads per library were obtained, from whose 99.8% of the sequenced data were retained. The alignment efficiency of uniquely mapped reads was 90.3, 89.5, and 89.8% for head kidney, liver, and anterior-mid intestine, respectively. In total, 218 differentially expressed genes (DEGs) were identified among all tissues, out of which, 141 were up- and 77 down-regluated. The enrichment analysis of DEGs revealed that SDY had a modulatory effect on several processes related to host’s immunity, oxygen’s carrier capacity, steroidogenesis, metabolism, and digestion. It is of special relevance the immunomodulatory effects of the tested ingredient as data from RNA-seq showed from the three target tissues analyzed. These results indicated that this ingredient in addition to being considered as a sustainable raw material for replacing conventional protein sources in aquafeeds may also be considered as a functional ingredient due to its content in β-glucans. The overall results of this study coupled with previous nutritional studies on this ingredient indicated the suitability of brewery’s by-products like SDY in aquafeeds for carnivorous species like gilthead seabream, as well as supporting a circular bioeconomy model that reuses, recovers, and recycles resources instead of producing wastes.

Sensitive photoelectrochemical detection of colitoxin DNA based on NCDs@CuO/ZnO heterostructured nanocomposites with efficient separation capacity of photo-induced carriers.

Ametal-organic framework (MOF) of Cu-TPA (terephthalic acid) microsphere was prepared, followed by calcinating the MOF precursor of Cu-TPA/ZIF-8 mixture to obtain the CuO/ZnO. N-doped carbon dots (NCDs) were employed to combine the CuO/ZnO composite to form a tripartite heterostructured architecture of NCDs@CuO/ZnO, which led to a fierce enlargement of the photocurrent response. This was ascribed to the thinner-shell structure of the CuO microsphere and the fact thathollow ZnO particles could sharply promote the incidence intensity of visible light. The more porous defectiveness exposed on CuO/ZnO surface was in favor of rapidly infiltrating electrolyte ions. The p-n type CuO/ZnO composite with more contact interface could abridge the transfer distance of photo-induced electron (e-1)/hole (h+) pairs and repress their recombination availably. NCDs not only could boost electron transfer rate on the electrode interface but also successfully sensitized the CuO/ZnO composite, which resulted in high conversion efficiency of photon-to-electron. The probe DNA (S1) was firmly assembled on the modified ITO electrode surface (S1/NCDs@CuO/ZnO) through an amidation reaction. Under optimal conditions, the prepared DNA biosensor displayed a wide linear range of 1.0 × 10-6 ~ 7.5 × 10-1nM and a low limit of detection (LOD) of 1.81 × 10-7nM for colitoxin DNA (S2) measure, which exhibited a better photoelectrochemistry (PEC) analysis performance than that obtained by differential pulse voltammetry techniques. The relative standard deviation (RSD) of the sensing platform for target DNA detection of 5.0 × 10-2nM was 6.3%. This proposed DNA biosensor also showed good selectivity, stability, and reproducibility, demonstrating that the well-designed and synthesized photoactive materials of NCDs@CuO/ZnO are promising candidates forPEC analysis.

Alternative approaches to measuring concentration in liner shipping

Shipping has always had a special relationship with competition law and economics. Even if special competition law regimes for the shipping industry continue to exist, most countries nowadays accept the notion that shipping markets should be more competitive. Competition authorities monitor this in a more or less regular fashion, with various market concentration indexes. The liner shipping industry is peculiar in its widespread cooperation schemes between carriers, in the form of vessel sharing agreements, also known as consortia. Carriers engage in cooperation with all of their major competitors in a system of consortia that is highly interlinked. This brings considerable risks of abuse of market power. Yet, the system of inter-linked consortia has never been systematically mapped, nor do competition authorities appear to monitor them. This article addresses this gap, by proposing alternative indicators, in addition to the traditional industry concentration indexes such as the Herfindahl–Hirschman Index (HHI), that take the reality of consortia into account. Here, five possible alternative indicators are considered: the market share of consortia and independent operators; the share of consortia exceeding market share thresholds; the industry market concentration of consortia; a modified HHI that takes consortia into account; and interlinkages between consortia. We analyse the current state of concentration of liner shipping on the basis of these indicators using a new and unique database that contains deployed ship capacity of container carriers on all of their liner services. Based on this dataset we provide an overview of differences in industry concentration across world regions and developments over time. Traditional indicators show an increase in industry concentration. For example, over the trade corridors to and from Northern Europe, the HHI scores in 2006 ranged from 604 to 2463, and from 1164 to 4882 in 2021. The alternative criteria show additional industry concentration. We show that in 2021, 704 out of more than 1500 agreements among carrier consortia had a combined market share of at least 30%, and 102 of them had a combined market share of at least 50%. We also observe that in 2021, the carriers active in alliances operated 85% of the consortia capacity. Although carriers that are in the same alliance operate most of these consortia, it is also noteworthy that carriers that are not in the same alliance operate a considerable part (24%) of the consortia. Our calculations of modified Herfindahl–Hirschman Index (MHHI)indexes that take consortia into account show that industry concentration is higher when consortia are taken into account: for example on the trade corridor Northern Europe-North America East Coast, the MHHI has reached the threshold of 2500 points, despite an HHI score of around 1500. In the conclusion of the article, we put forward ways in which these alternative indicators could be used by competition authorities.

Hemoglobin-based oxygen carriers camouflaged with membranes extracted from red blood cells: Optimization and assessment of functionality

Despite being an indispensable clinical procedure, the transfusion of donor blood has important limitations including a short shelf-life, limited availability and specific storage requirements. Therefore, a lot of effort has been devoted to developing hemoglobin (Hb)-based oxygen carriers (HBOCs) that are able to replace or complement standard blood transfusions, especially in extreme life-threatening situations. Herein, we employed a Hb-loaded poly(lactide-co-glycolide) core which was subsequently coated with nanozymes to protect the encapsulated Hb from oxidation by reactive oxygen species. To render HBOCs with long circulation in the vasculature, which is a crucial requirement to achieve the high oxygen demands of our organism, the carrier was coated with a red blood cell-derived membrane. Three coating methods were explored and evaluated by their ability to repel the deposition of proteins and minimize their uptake by an endothelial cell line. Preservation of the oxygen carrying capacity of the membrane-coated carrier was demonstrated by an oxygen-binding and releasing assay and, the functionality resulting from the entrapped nanozymes, was shown by means of superoxide radical anion and hydrogen peroxide depletion assays. All in all, we have demonstrated the potential of the membrane-coated nanocarriers as novel oxygen carrying systems with both antioxidant and stealth properties.

Controlling the Structural Properties and Optical Bandgap of PbO–Al2O3 Nanocomposites for Enhanced Photodegradation of Methylene Blue

In the present work, PbO-x wt% Al2O3 nanocomposites (where x = 0, 10, 20, 30, 40, 50, 60, 70, and 100 wt%) were prepared by a microwave irradiation method. Their structural parameters, morphology, and chemical bonds, were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FTIR). It was noticed that the produced phases have an orthorhombic crystal structure and the smaller average crystallite sizes were formed when the ratio of Al2O3 is 40 wt%. The FTIR analysis reveals the formation of various bonds between Al or Pb and O. The TEM analysis reveals that the PbO-x%Al2O3 composites (x = 20, 40, and 60), composed of dense particles, and their size are smaller compared to the pure Al2O3 sample. The optical bandgap obeys the direct allowed transition and decreases from 4.83 eV to 4.35 eV as the PbO ratio in the composites increases from 0 to 100%. The intensity of the photoluminescence emission, at the same wavelength, increases as the PbO ratio increases from 0% to 60% implying that increasing the PbO content increases the capacity of free carriers within the trap centers. The prepared composites are used as a catalyst to remove the methylene blue (MB) from the wasted water under UV-visible or visible light irradiations. The photocatalytic degradation of MB was investigated by applying various kinetic models. It was found that the PbO-30% Al2O3, and PbO-40% Al2O3 composites are the best ones amongst other compositions. Furthermore, the pseudo-second-order model is the best model for describing the deterioration mechanism among the models studied. The formed composites could be suitable for the degradation of organic dyes for water purification as well as applications that required a higher optical bandgap.

Improved Oxygen Transport Capacity and Reactivity of Catalytic Oxygen Carriers for Low Temperature Chemical-Looping Oxidation of H2s for Efficient Sulfur Recovery from Natural Gas

Improved Oxygen Transport Capacity and Reactivity of Catalytic Oxygen Carriers for Low Temperature Chemical-Looping Oxidation of H2s for Efficient Sulfur Recovery from Natural Gas

Lipid-based nanocarriers for oral delivery of peptides

Therapeutic peptides can treat a wide variety of diseases with selective and potent action. Their oral bioavailability is strongly limited by an important proteolytic activity in the intestinal lumen and poor permeation across the intestinal border. We have evaluated the capacity of solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) to overcome both oral bioavailability limiting aspects, using leuprolide (LEU) as model peptide. Lipidization of LEU by formation of a hydrophobic ion pair (HIP) with sodium docusate enables a significant increase of peptide encapsulation efficiency in both SLN and NLC. The nanocarriers, obtained by high-pressure homogenization, measured 120 nm and were platelet shaped. Regarding the protective effect towards proteolytic degradation, only NLC maintained LEU integrity in presence of trypsin. Intestinal transport, evaluated on Caco-2 (enterocyte-like model) and Caco-2/HT29-MTX (mucin-secreting model) monolayers, showed nanocarriers internalization by enterocytes but no improvement of LEU permeability. Indeed, the combination of nanoparticles platelet-shape with the poor stability of the HIP in the transport medium induces a high burst release of the peptide, limiting nanoparticles capacity to transport LEU across the intestinal border. Stability of peptide lipidization needs to be improved to withstand biorelevant medium to benefit from the advantages of encapsulation in solid lipid nanocarriers and consequently improve their oral bioavailability.

MODELING THE DYNAMICS OF THERMAL ENERGY ACCUMULATORS AS CONTROL OBJECTS

The article defines the relevance of research on options for using heat accumulators in the heat supply system of industrial premises. Typical technological schemes of liquid heat accumulators are considered and shortcomings of existing mathematical models are determined. The technological scheme of a capacitive type battery is selected and analyzed, as the most common in solar heating and hot water systems. It has been established that for a non-stationary process, the thermal inertia of the body reinforcement and thermal insulation cannot be neglected, therefore, the storage tank cannot be considered as a single-capacity object. Based on the analysis of the heat balance of structural elements of heat storage devices, a mathematical model of the dynamics of the accumulator tank as a two-capacity object with lumped parameters is formulated. The resulting simplified mathematical model makes it possible to identify the simulation object (a capacitive type water accumulator). In the considered embodiment, the heat accumulator is used in hot solar water supply systems for preheating water. For use in dual-circuit systems of solar heating and hot water supply, heliolectors with antifreeze are used, and water is heated in heat storage tanks using heat exchangers. The formulated mathematical model of a tank of a combined accumulator with a heat exchanger when used as a liquid heat carrier - antifreeze (to exclude icing of the system), in which, to simplify the model (reduce the order), the heat capacity of the tubes is related to the heat capacity of the heat carrier in the volume of the tubes, and the mass of the body to the mass of liquid in it . For the development and analysis of an automatic temperature control system, the obtained models are a system of nonlinear equations, the solution of which is advisable to carry out in computer environments.

Heat transfer enhancement strategies for eco-friendly dry hobbing considering the heat exchange capacity of chips

To reduce the adverse effect of thermal accumulation, a better understanding of heat transfer is quite necessary for eco-friendly dry hobbing, which is completely different from common turning and milling. The paper focuses on the cutting heat transfer enhancement of dry hobbing with consideration of the heat exchange capacity of dominant heat carrier. Firstly, the generation and transfer process of cutting heat are analyzed on a micro level according to the interrupted cutting characteristic with multiple cutting edge of dry hobbing. Secondly, a multi-field coupling simulation combined with thermal imaging reconstruction is carried out to determine the dominant heat carrier of cutting heat. Furthermore, influence factors are investigated for the heat exchange capacity of the dominant heat carrier (the chips) based on the modified model of specific cutting energy. Finally, heat transfer enhancement strategies are investigated considering the heat exchange capacity of chips. The findings demonstrate wide potential applications for thermal deformation reduction and machining quality improvement in dry hobbing process.

Synthesis and Characterization of Nanoporous Carbon Carriers for Losartan Potassium Delivery.

Losartan potassium is most commonly used for the treatment of hypertension. In recent years, new applications of this drug have emerged, encouraging the design of novel nanoporous carriers for its adsorption and release. The purpose of this study was to synthesize ordered mesoporous carbon vehicles via a soft-templating method altered with the use of nitrogen precursors and via a hard-templating method followed by chitosan functionalization. As a result, the materials obtained differed in nitrogen content as well as in the number of total surface functional groups. The impact of the modification on the physicochemical properties of carbon carriers and their interaction with losartan potassium during adsorption and release processes was examined. The materials were characterized by various morphologies, specific surface areas (101–1180 m2 g−1), and the amount of acidic/basic oxygen-containing functional groups (1.26–4.27 mmol g−1). These features, along with pore sizes and volumes, had a key effect on the sorption capacity of carbon carriers towards losartan potassium (59–161 mg g−1). Moreover, they contributed to the differential release of the drug (18.56–90.46%). Losartan potassium adsorption onto the surface of carbonaceous materials was mainly based on the formation of hydrogen bonds and π–π interactions and followed the Langmuir type isotherm. It has been shown that the choice of the method of carbon carriers’ synthesis and their modification allows for the precise control of the kinetics of the losartan potassium release from their surface, resulting in rapid or sustained drug liberation.