Could the Magnetic Star HD 135348 Possess a Rigidly Rotating Magnetosphere?

We report the detection and characterization of a new magnetospheric star, HD 135348, based on photometric and spectropolarimetric observations. The TESS light curve of this star exhibited variations consistent with stars known to possess rigidly rotating magnetospheres (RRMs), so we obtained spectropolarimetric observations using the Robert Stobie Spectrograph (RSS) on the South African Large Telescope (SALT) at four different rotational phases. From these observations, we calculated the longitudinal magnetic field of the star 〈B z 〉, as well as the Alfvén and Kepler radii, and deduced that this star contains a centrifugal magnetosphere. However, an archival spectrum does not exhibit the characteristic “double-horned” emission profile for Hα and the Brackett series that has been observed in many other RRM stars. This could be due to the insufficient rotational phase coverage of the available set of observations, as the spectra of these stars significantly vary with the star’s rotation. Our analysis underscores the use of TESS in photometrically identifying magnetic star candidates for spectropolarimetric follow-up using ground-based instruments. We are evaluating the implementation of a machine-learning classifier to search for more examples of RRM stars in TESS data.

Re(I) Complexes as Backbone Substituents and Cross-Linking Agents for Hybrid Luminescent Polysiloxanes and Silicone Rubbers

This study focuses on the synthesis of hybrid luminescent polysiloxanes and silicone rubbers grafted by organometallic rhenium(I) complexes using Cu(I)-catalyzed azido-alkyne cycloaddition (CuAAC). The design of the rhenium(I) complexes includes using a diimine ligand to create an MLCT luminescent center and the introduction of a triple C≡C bond on the periphery of the ligand environment to provide click-reaction capability. Poly(3-azidopropylmethylsiloxane-co-dimethylsiloxane) (N3-PDMS) was synthesized for incorporation of azide function in polysiloxane chain. [Re(CO)3(MeCN)(5-(4-ethynylphenyl)-2,2′-bipyridine)]OTf (Re1) luminescent complex was used to prepare a luminescent copolymer with N3-PDMS (Re1-PDMS), while [Re(CO)3Cl(5,5′-diethynyl-2,2′-bipyridine)] (Re2) was used as a luminescent cross-linking agent of N3-PDMS to obtain luminescent silicone rubber (Re2-PDMS). The examination of photophysical properties of the hybrid polymer materials obtained show that emission profile of Re(I) moiety remains unchanged and metallocenter allows to control the creation of polysiloxane-based materials with specified properties.

Fabrication and complex investigation of LAFE based on CNT by PECVD with island catalyst

This paper presents a study of large area field emitter based on carbon nanotubes grown by PECVD method on Si/SiO2 substrate with Fe catalyst. The catalyst was deposited by CVD on the substrate from ferrocene in the form of islands. The sample creation technology was described and results of the emission properties study were presented. Current-voltage characteristics were registered and tested for compliance with the cold field emission regime. The fluctuation statistic of effective microscopic parameters was constructed. Using data from a computerized field projector, the emission profile of the sample was calculated.

Emission Pattern of Compression Ignition Engine Fueled with Blends of Tropical Almond Seed Oil-Based Biodiesel using Artificial Neural Network

Engine pollutants have been a significant source of concern in most countries around the world because they are one of the major contributors to air pollution, which causes cancer, lung disorders, and other severe illnesses. The need to reduce emissions and its consequences has prompted studies into the emission profile of internal combustion engines running on particular fuels. To this end, this study employed the power of Artificial Neural Networks (ANNs) to investigate the impact of injection timing on the emission profile of Compression Ignition Engines fuelled with blends of Tropical Almond Seed Oil based-biodiesel; by conducting a series of experimental tests on the engine rig and using the results to train the ANNs; to predict the emission profile to full scale. Blend percentages, load percentages, and injection timings were used as input variables, and engine emission parameters were used as output variables, to train the network. The results showed that injection timing affect emission output of CI engines fuelled with Tropical Almond Oil based biodiesel; and for the emission pattern to be friendly, injection timing must rather be retarded and not advanced. The results also showed that for different engine emission parameters, there is a strong association between the ANN output results and the actual experimental values; with mean relative error values less than 10%, which fall within the acceptable limits. For emission of CI engines fuelled with Tropical Almond Oil based biodiesel to be friendly in pattern, injection timing must be relatively retarded. The study also concluded that Artificial Neural Network (ANN) is a reliable tool for predicting Compression Ignition Engines emission profiles.

Reductive Amination Reaction for the Functionalization of Cellulose Nanocrystals

Cellulose nanocrystals (CNCs) represent intriguing biopolymeric nanocrystalline materials, that are biocompatible, sustainable and renewable, can be chemically functionalized and are endowed with exceptional mechanical properties. Recently, studies have been performed to prepare CNCs with extraordinary photophysical properties, also by means of their functionalization with organic light-emitting fluorophores. In this paper, we used the reductive amination reaction to chemically bind 4-(1-pyrenyl)butanamine selectively to the reducing termini of sulfated or neutral CNCs (S_CNC and N_CNC) obtained from sulfuric acid or hydrochloric acid hydrolysis. The functionalization reaction is simple and straightforward, and it induces the appearance of the typical pyrene emission profile in the functionalized materials. After a characterization of the new materials performed by ATR-FTIR and fluorescence spectroscopies, we demonstrate luminescence quenching of the decorated N_CNC by copper (II) sulfate, hypothesizing for these new functionalized materials an application in water purification technologies.

Temperature and Different Organs Create Volatile Profile Differences of Edible Gynura [Gynura bicolor (Roxb. ex Willd.) DC]

The volatile profile of the edible vegetable Gynura bicolor [Gynura bicolor (Roxb. ex Willd.) DC] was analyzed using gas chromatography-mass spectrometry (GC-MS). Isocaryophyllene (23.2%), α-pinene (16.8%), α-humulene (9.1%), β-pinene (7.3%), and copaene (7.0%) were identified as the major compounds in the leaves. In the stems, α-pinene (27.1%), β-pinene (13.0%), isocaryophyllene (7.8%), β-myrceneb (7.8%), 1-undecene (5.7%), and copaene (5.3%) were the main components. G. bicolor grows best at 25 °C. When cultivated at different temperatures (20 to 35 °C in incements of 5 °C), the volatile profiles shifted. The proportion of isocaryophyllene was lower at 20 °C than at the other temperatures. The relative amounts of α-pinene and α-humulene were highest at 20 °C, whereas copaene was highest at 35 °C. Principal component analysis (PCA) was used to explore the correlation between volatile compounds identified from the vegetative tissues and temperature treatments. It reveals the same trend with the previous statements and the first principal component (PC1) and the second principal component (PC2) explains up to 90% of the variance. Experimental results revealed that both temperature and vegetative organ correlate with the volatile emission profile of G. bicolor.

The Combined Effect of Alcohols and Calophyllum inophyllum Biodiesel Using Response Surface Methodology Optimization

In this experimental study, the performance of the diesel engine was analyzed for biodiesel derived from Calophyllum inophyllum. The impact of the addition of additives such as N-octanol and N-butanol with Calophyllum inophyllum biodiesel has been assessed. Impact of the application of hybrid N-octanol and N-Butanol with biodiesel on emission profile used for the engine performance has also been demonstrated. Response surface analysis of alcohol additives-biodiesel blend was performed separately in this study for the engine efficiency and emission profile. A combination of N-octanol and N-Butanol presented the highest brake thermal efficiency (BTE) and lowest carbon monoxide (CO) emission among the ternary blends of octanol. N-Butanol-biodiesel blend presented the lowest hydrocarbon (HC) emission among the blends of N-butanol. N-Octanol with 5 and 10% addition with biodiesel showed the lowest HC emissions among the blends of octanol. The response surface methodology (RSM) optimization revealed that the optimized thermal efficiency and emission were obtained at full load and minimum load, respectively. The addition of N-octanol hindered the emission at all loads, while N-butanol reduced it at higher loads. A strong correlation between the load and alcohol additives on the engine performance and emission profile has been obtained using the RSM optimization approach. The R-squared value obtained from the RSM was 0.92 and emission profile has been characterized.

Effective ionization coefficients for low current dc discharges in alcohol vapours at low pressure

This paper presents results for effective ionisation coefficients ($$\alpha _{\mathrm {eff}}/N$$ α eff / N , N—gas density) obtained from the breakdown voltage and emission profile measurements in low-pressure dc discharges in vapours of alcohols: methanol, ethanol, isopropanol, and n-butanol. Our results for $$\alpha _{\mathrm {eff}}/N$$ α eff / N are determined from the axial emission profiles in low-current Townsend discharge and lay in the interval of reduced electric field E/N (E—electric field, N—gas density), from 1 kTd to 8.8 kTd. We also give a comparison of our experimental results with those from the available literature. Our data cover the high E/N range of the standard operating conditions and in the region where other data are available we have a good agreement. Graphic abstract