Rotating Detonation Combustor Research at the University of Cincinnati

Rotating detonation combustors (RDC) are at the forefront of pressure gain combustion (PGC) research. The simplicity in design and the ease of assembly makes it a promising technology that could be integrated into existing combustor architectures. This is, however, coupled with the considerable complexities of the detonation-based flow field, and the associated modes and coupling mechanisms. The current paper is an overview of the research done at the University of Cincinnati to address some of the challenges and questions pertaining to the physics of RDC operation. Issues such as combustor geometry, injection schemes and mixing, varied reactants behavior and modes of RDC operation are discussed. The effects of pressurization of the combustor, along with other detonation enhancement strategies are also deliberated upon. When appropriate, parallels are drawn to the phenomena of high frequency combustion instabilities to address the similarities in observations between the two fields.     

Synthesis of Small‐Sized,Porous, and Low‐Toxic Magnetite Nanoparticles by Thin POSS Silica Coating

In this communication, we report the synthesis of small‐sized (<10 nm), water‐soluble, magnetic nanoparticles (MNPs) coated with polyhedral oligomeric silsesquioxanes (POSS), which contain either polyethylene glycol (PEG) or octa(tetramethylammonium) (OctaTMA) as functional groups. The POSS‐coated MNPs exhibit superparamagnetic behavior with saturation magnetic moments (51–53 emu g^?1) comparable to silica‐coated MNPs. They also provide good colloidal stability at different pH and salt concentrations, and low cytotoxicity to MCF‐7 human breast epithelial cells. The relaxivity data and magnetic resonance (MR) phantom images demonstrate the potential application of these MNPs in bioimaging.     

Stability-indicating RP-HPLC method development and validation for determination of nine impurities in apixaban tablet dosage forms. Robustness study by quality by design approach

A quality by design (QbD) based high-resolution HPLC method is described for determination of impurities in apixaban (APX) in the tablet dosage form. Employing a simple and stability-indicating HPLC method, nine known impurities were quantified with good peak resolution. Mobile phase A (MP-A) was prepared with buffer and acetonitrile 90:10 v/v, while mobile phase B (MP-B) contained water and acetonitrile 10:90 v/v. The gradient program was 0 min, MP-A 75%, B 25%; 20 min, MP-A 65%, B 35%; 30 min, MP-A 40%, B 60%; 40min, MP-A 40%, B 60%; 42 min, MP-A 75%, B 25%; and 50 min, MP-A 75%, B 25%. The chromatographic separation was achieved using a Zorbax RX C₁₈ 250 × 4.6 mm column, 5 μm (1.0 ml min⁻¹, 280 nm, 50 μl) and a column temperature of 40°C. Several separation studies were carried out using design of experiments to optimize the method. Validation results confirm the applicability of the developed method for quality analysis and stability studies of the regular product on the manufacturing stream.     

Radiochemical studies using 59Fe and 35S provide evidence for iron-regulated uptake of sulfur in wheat

Ecological half-lives of radiocesium were observed on Izu-Oshima Island, Japan, a place which experiences typhoons annually. The estimated ecological half-lives (uncertainty) based on the observations above an asphalt and a bare surface were 1.6 year (31.6%) and 1.9 year (14.4%), respectively; those of ¹³⁴Cs and ¹³⁷Cs in soil were 1.5 year (7.2%) and 4.0 year (5.9%), respectively. The radiation level was quickly returned to the original level compared to other locations that do not experience such typhoon activity.

     

Chemically characterised Pimenta dioica (L.) Merr. essential oil as a novel plant based antimicrobial against fungal and aflatoxin B1 contamination of stored maize and its possible mode of action

Abstract

The chemical characterisation of Pimenta dioica essential oil (PDEO) revealed the presence of 50 components, amongst which α-Terpineol (30.31%) was the major component followed by β-Linalool (6.75%) and γ-Terpinene (4.64%). The oil completely inhibited the growth of aflatoxin B₁ secreting strain Aspergillus flavus LHP-VS-8 and aflatoxin B₁ production at 2.5?µL/mL and 1.5?µL/mL, respectively. The oil caused dose dependent reduction of methylglyoxal (an AFB₁ inducer), enhanced leakage of Ca²⁺, Mg²⁺ and K⁺ ions and significantly reduced ergosterol content of fungal plasma membrane. During in situ experiments, PDEO exhibited complete protection of fumigated maize cob slices from fungal infestation without affecting seed germination. The chemically characterised PDEO is recommended as a plant based preservative and shelf life enhancer of food commodities by preventing fungal growth, AFB₁ production and lipid peroxidation. This is the first report on PDEO as inhibitor of AFB₁ secretion and methylglyoxal biosynthesis.     

Migration of active filaments under Poiseuille flow in a microcapillary tube

The European Physical Journal E - The buckling and twisting of slender, elastic fibers is a deep and well-studied field. A slender elastic rod that is twisted with respect to a fixed end will...     

Improvement in the yield and quality of kalmegh (Andrographis paniculata Nees) under the sustainable production system

Andrographis paniculata Nees is an annual erect herb with wide medicinal and pharmacological applications due to the presence of andrographolide and other active chemical constituents. The large-scale cultivation of the kalmegh is not in practice. The aim of this study was to establish sustainable production systems of A. paniculata cv CIM-Megha with the application of different bioinoculants and chemical fertilisers. A. paniculata herb and andrographolide yield in the dried leaves was found to be highest (218% and 61.3%, respectively) in treatment T₃ (NPK+Bacillus sp.) compared with T₁ (control). The soil organic carbon, soil microbial respiration, soil enzymes activity and available nutrients improved significantly with combined application of bioinoculants and chemical fertilisers.     

Visible Light Mediated Halogen Atom Transfer to Access Polyhalogenated and Deuterated Lactams from Alkyl Halides

A visible light mediated protocol for the synthesis of polyhalogenated and deuterated δ- and γ-lactams from readily available alkyl halides is reported. The reaction involves the generation of haloalkyl radicals through halogen atom transfer (XAT) and subsequent arylalkylation of olefins to afford dihydroisoquinolinones and oxindoles. This new XAT protocol exhibits wide scope under mild conditions and enables access to new halogenated chemical space.     

Synthesis and characterization of ternary nanocomposites of TiO2/rGO/CdS as an efficient catalyst for photo-degradation of methyl orange

Novel ternary composite photocatalysts have been successfully prepared by TiO₂ nanofibers, reduced graphene oxide, and CdS nanoparticles (TiO₂/rGO/CdS) by using electrospinning technique with easy chemical methods. The structures and their properties are examined by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and field-emission scanning electron microscope (FESEM). The structural characterization of the composite reveals that pure TiO₂ NFs and CdS NPs crystalline very well and the reduced graphene oxide is tightly composed with TiO₂ NFs and CdS Nps. The photodegradation of methyl orange (MO) under UV light illumination is significantly enhanced compared with that of bare materials. This ternary composite degrades methyl orange within 75 min. The enhanced photocatalytic degradation performance resulted from effective separation of e–h pairs with rGO sheets and also contributed for high rate degradation efficiency. This novel ternary composite has a potential application of wastewater purification and utilization for energy conversions.