Metal Organic Framework Crystals in Mixed‐Matrix Membranes: Impact of the Filler Morphology on the Gas Separation Performance

Mixed‐matrix membranes comprising NH₂‐MIL‐53(Al) and Matrimid or 6FDA‐DAM have been investigated. The metal organic framework (MOF) loading has been varied between 5 and 20 wt%, while NH₂‐MIL‐53(Al) with three different morphologies, nanoparticles, nanorods, and microneedles has been dispersed in Matrimid. The synthesized membranes have been tested in the separation of CO₂ from CH₄ in an equimolar mixture. At 3 bar and 298 K for 8 wt% MOF loading, incorporation of NH₂‐MIL‐53(Al) nanoparticles leads to the largest improvement compared to nanorods and microneedles. The incorporation of the best performing filler, i.e., NH₂‐MIL‐53(Al) nanoparticles, into the highly permeable 6FDA‐DAM has a larger effect, and the CO₂ permeability increases up to 85% with slightly lower selectivities for 20 wt% MOF loading. Specifically, these membranes have a permeability of 660 Barrer with a CO₂/CH₄ separation factor of 28, leading to a performance very close to the Robeson limit of 2008. Furthermore, a new non‐destructive technique based on Raman spectroscopy mapping is introduced to assess the homogeneity of the filler dispersion in the polymer matrix. The MOF contribution can be calculated by modeling the spectra. The determined homogeneity of the MOF filler distribution in the polymer is confirmed by focused ion beam scanning electron microscopy analysis.     

Vibrational Energy Transport in Hybrid Ordered/Disordered Nanocomposites: Hybridization and Avoided Crossings of Localized and Delocalized Modes

Vibrational energy transport in disordered media is of fundamental importance to several fields spanning from sustainable energy to biomedicine to thermal management. This work investigates hybrid ordered/disordered nanocomposites that consist of crystalline membranes decorated by regularly patterned disordered regions formed by ion beam irradiation. The presence of the disordered regions results in reduced thermal conductivity, rendering these systems of interest for use as nanostructured thermoelectrics and thermal device components, yet their vibrational properties are not well understood. Here, the mechanism of vibrational transport and the reason underlying the observed reduction is established in detail. The hybrid systems are found to exhibit glass‐crystal duality in vibrational transport. Lattice dynamics reveals substantial hybridization between the localized and delocalized modes, which induces avoided crossings and harmonic broadening in the dispersion. Allen/Feldman theory shows that the hybridization and avoided crossings are the dominant drivers of the reduction. Anharmonic scattering is also enhanced in the patterned nanocomposites, further contributing to the reduction. The systems exhibit features reminiscent of both nanophononic materials and locally resonant nanophononic metamaterials, but operate in a manner distinct to both. These findings indicate that such “patterned disorder” can be a promising strategy to tailor vibrational transport through hybrid nanostructures.     

Chemical and microbiological status and volatile profiles of mouldy Civil cheese,a Turkish mould‐ripened variety

The objective of this study is to characterise the gross chemical and microbiological status and identify the volatile compounds of mouldy Civil cheeses. A total of forty‐one samples were surveyed, and gross compositional status of the cheeses was (as mean values): 6.5 for pH, 6.2% for fat‐in‐dry matter, 51.8% for moisture and 15.3% for water‐soluble nitrogen (as% of total nitrogen). Chemical composition of the cheese samples varied widely. Mouldy Civil cheese has similar pH values and moisture contents when compared with blue‐type cheeses, but it has distinct feature for fat contents. The microbiological counts of the samples were found to be high and some samples contained coliform bacteria. A total of 95 volatiles, including esters (28), acids (6), ketones (12), aldehydes (3), alcohols (15), terpenes (10), sulphur compounds (3) and miscellaneous (18), were identified in the volatile fractions of the cheeses, and principal volatile groups were esters, alcohols and ketones.     

Effects of Penicillium roqueforti and whey cheese on gross composition,microbiology and proteolysis of mould‐ripened Civil cheese during ripening

Four different types of mould‐ripened Civil cheese were manufactured. A defined (nontoxigenic) strain of a Penicillium roqueforti (SC 509) was used as the secondary starter with and without addition of the whey cheese (Lor); in parallel, secondary starter‐free counterparts were manufactured. Chemical composition, microbiology and proteolysis were studied during the ripening. The incorporation of whey cheese in the manufacture of mould‐ripened Civil cheese altered the gross composition and adversely affected proteolysis in the cheeses. The inoculated P. roqueforti moulds appeared to grow slowly on those cheeses, and little proteolysis was evident in all cheese treatments during the first 90 days of ripening. However, sharp increases in the soluble nitrogen fractions were observed in all cheeses after 90 days. Microbiological analysis showed that the microbial counts in the cheeses were at high levels at the beginning of ripening, while their counts decreased approximately 1–2 log cfu/g towards the end of ripening.     

Effect of Bicarbonate Salts and Sequential Using of Frying Oil on Acrylamide and 5-Hydroxymethylfurfural Contents in Coated Fried Chicken Meat

In this research, the effect of different bicarbonate salts (sodium and ammonium) and their doses (0, 1, 2, and 3 g/100 g raw material) in the coating batter formula use and the sequential use of frying oil (1st, 2nd, 3rd, and 4th) on 5-hydroxymethylfurfural and acrylamide contents in coated fried chicken meat. The addition of sodium bicarbonate was efficient for reducing acrylamide content, but it increased browning and 5-hydroxymethylfurfural content compared to the control. When increasing the doses of sodium and ammonium bicarbonate from 1 to 3 g/100 g of raw material, the acrylamide content of samples did not change significantly, although adding sodium bicarbonate significantly reduced the acrylamide content as a control. These research results showed that using about 1 g/100 g raw material sodium bicarbonate rather than ammonium bicarbonate and as little frying oil as possible use during the production of coated and fried meat results in lower contents of 5-hydroxymethylfurfural and acrylamide.     

Mechanism of boron tribromide electroreduction

This study was carried out to investigate the electrochemical behavior of boron tribromide in dimethlyformamide. The reduction of the compound was found to follow a CE mechanism. The kinetic parameters and the diffusion coefficient were calculated by the use of ultramicrodisc electrodes and chronoamperometry. The number of electrons transferred was found to be 2 by rotating disc and ultramicro disc electrodes and 3 by coulometry. These results are in good accordance with those obtained from molten boron salts. This study is important in regard to electrochemical boronizing at low temperatures.     

Determination of the quality and purity characteristics of olive oils obtained from different regions of Turkey,depending on climatic changes

Virgin olive oils (VOOs) obtained from olives grown in different regions of Turkey under changing climatic conditions sometimes show different sensory and chemical properties. This study was planned to determine whether these deviations are due to climatic changes or not. For this purpose, five different olive varieties (Ayvalık, Memecik, Gemlik, Nizip Yağlık, Kilis Yağlık) of commercial importance were harvested from the provinces/districts (four different region) where cultivation is intense during the 2017/2018–2020/2021 harvest years. Every year, olive samples were collected from 3 orchards from 13 provinces/districts. One hundred and fifty-six samples were subjected to the purity, quality and sensory analysis. Basic climatic values (average, minimum and maximum temperature, humidity and precipitation) were examined for four consecutive years. All of the examined olive oil samples were determined within the legal limits in terms of fatty acid composition and fatty acid ethyl ester values. However, delta-7-stigmastenol value from the sterol composition was found to be above 0.5% in some samples in all the years studied (total 21 samples). Delta-7-stigmastenol values of olive oil samples varied between 0.16% and 1.14%. Multiple linear regression analysis was applied using a genetic algorithm-based inverse least squares method to determine whether there is a relationship between climate data and delta-7-stigmastenol values. According to this result, it has been determined that the delta-7-stigmastenol value is high when the annual average relative humidity is low and the annual average temperature is high. There is an urgent need to make forward-looking plans due to climate change.     

Effect of different denture adhesives on retention of complete dentures: an in vivo study

The increase in prevalence of tooth loss with the effect of population aging produces the growing need for complete dentures. The success and acceptance of complete dentures by the patient depends on sufficient retention and stability. Therefore, denture adhesives are regularly used by denture wearers to improve the function of complete denture. We evaluated the effect of three different denture adhesives (Corega, Protefix, Fittydent) on the retention of maxillary complete denture (MCD) using with digital dynamometer (DD). For this purpose, denture adhesives were applied on MCDs of 30 participants. After chewing procedure, the force was applied at 45° to the palatal surface of denture by DD. Dislodgement force was recorded by means of Newton. There were four measurements on each patient including; group of control: Group C; Group CR: Corega; Group F: Fittydent; Group P: Protefix. The result of the study was statistically evaluated by using analysis of variance (ANOVA) and Tukey HSD test. Statistics of ANOVA showed a significant difference among all the four groups (p = 0.00, <0.05). Tukey HSD test indicated that there was a statistical difference between Group F and the other groups, but there was not a significant difference between the other groups. The highest adhesive strength value was observed in group F, the lowest in group C. Use of denture adhesives improved the retentive strength of complete denture.