Castor oil dehydration kinetics

The dehydration reaction kinetics of castor oil was investigated with sodium bisulfate-sodium bisulfite mixture (SB-SB) or p-toluenesulfonic acid as catalyst. Reactions were carried out at 210, 220, and 230°C, and a kinetic model was determined for each case. The reactions with SB-SB catalyst at 210 and 220°C and with p-toluenesulfonic acid at 210°C followed second-order kinetics. A first-order rate equation showed the best fit to the experimental data for the reaction with SB-SB at 230°C. p-Toluenesulfonic acid-catalyzed reactions at 220 and 230°C were also first-order reactions. Additionally, some mathematical equations were derived between iodine value, refractive index, viscosity, and reaction time.     

Chemical changes of three native Turkish hazelnut varieties (Corylus avellana L.) during fruit development

Three native hazelnut varieties from Turkey, namely, Tombul, Palaz, and Badem, were examined for their proximate composition, minerals, and fatty acid profiles, as well as polyphenol oxidase (PPO), peroxidase (POD), and lipase activities during fruit development stages (early stage: ES, middle stage: MS, and harvest stage: HS). Proximate composition varied considerably (dry weight basis) from ES to MS. Fat was the predominant component at all stages and showed increasing trends. Six essential minerals (calcium, iron, magnesium, phosphorus, potassium, and zinc) were analysed (dry weight basis). Consuming recommended daily amount of 42.5 g hazelnut at HS supplies 23.3–25.0% of phosphorus, 11.6–18.1% of magnesium, 7.0–18.9% of iron, 4.9–8.9% of zinc, 5.1–5.7% of calcium, and 5.1–5.3% of potassium for recommended dietary allowances or adequate intake for adults. Significant (P < 0.05) decreasing trends were found in all mineral contents from early development to maturity, with some exceptions. Sixteen fatty acids were identified, among which 18:1ω9 was by far the most predominant one, followed by 18:2ω6, 16:0, and 18:0. As expected, total monounsaturated fatty acids constituted the main group of fatty acids ranging from 75.51 to 81.07% in Tombul, from 78.21 to 82.71% in Palaz, and from 73.69 to 81.65% in Badem through the maturation stages. In contrast, total polyunsaturated fatty acids showed decreasing trends from ES to HS. No significant changes (P > 0.05) were observed in total saturated fatty acids at different maturation stages. Tombul variety had the lowest PPO activity compared to those of Palaz and Badem. Badem showed highest POD activity compared to Tombul and Palaz at three stages of maturation and significant decreases (P < 0.05) in all hazelnut samples were observed in POD activity from ES to HS. No lipase activity was detected in any hazelnut samples at ES and MS, except in Badem at MS. In contrast, lipase activity was detected in all hazelnut samples at HS. These results suggest that some proximate compositions, minerals, and fatty acids gave good indications during fruit development stages, whereas enzymatic activities of PPO, POD, and lipase behaved differently among varieties and fruit development stages.     

Improving hydrophobicity on polyurethane-based synthetic leather through plasma polymerization for easy care effect

This study reports on the deposition of a hydrophobic coating on polyurethane (PU)-based synthetic leather through a plasma polymerization method and investigates the hydrophobic behavior of the plasma-coated substrate. The silicon compound of hexamethyldisiloxane (HMDSO), inactive gas argon (Ar), and toluene were used to impart surface hydrophobicity to a PU-based substrate. Surface hydrophobicity was analyzed by water contact angle measurements. Surface hydrophobicity was increased by deposition of compositions of 100% HMDSO, 3:1 HMDSO/toluene, and 1:1 HMDSO/toluene. Optimum conditions of 40 W, 30 s plasma treatment resulted in essentially the same initial contact angle results of approximately 100° for all three treatment compositions. The initial water contact angle for untreated material was about 73°. A water droplet took 1800 s to spread out on the plasma-treated sample after it had been placed on the sample surface. An increase in plasma power also led to a decrease in contact angle, which may be attributed to oxidization of HMDSO during plasma deposition. XPS analysis showed that plasma polymerization of HMDSO/toluene compositions led to a significant increase in atomic percentage of Si compound responsible for the hydrophobic surface. The easy clean results for the treated and untreated PU-based synthetic leather samples clearly showed that the remaining stain on the plasma-polymerized sample was less than that of untreated sample. The plasma-formed coating was both hydrophobic and formed a physical barrier against water and stain.     

Low-methoxyl pectin–zeolite hydrogels controlling drug release promote in vitro wound healing

This study presents the design of novel hydrogel films, based on low-methoxyl (LM) pectin and NaA- or ZnA-zeolite particles, to serve as wound dressing materials with controlled drug delivery properties. We studied the effects of the preparation method of hydrogels, the amounts of crosslinker, drug and zeolite, and the type of cation in zeolites on the drug release mechanisms from the hydrogels. Ionic strengths of both film and external medium dictated the drug release behavior of the films, while the other parameters also played essential roles. NaA-zeolite hydrogels prepared using membrane diffusion controlled system, could reach a drug release ratio of 86% within 5 h. The drug-free hydrogels displayed no cytotoxicity while supporting cell proliferation and migration. Our cost-effective LM pectin–zeolite hydrogels promise to be effective wound dressing materials with controlled drug delivery ability, transparency, good swelling properties, ability to hold fluids, good oxygen transmission rate, and biocompatibility. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47640.     

Learning temporal logic formulas from suboptimal demonstrations: theory and experiments

Autonomous Robots - We present a method for learning multi-stage tasks from demonstrations by learning the logical structure and atomic propositions of a consistent linear temporal logic (LTL)...     

Effects of suni-bug (<Emphasis Type="Italic">Eurygaster</Emphasis> spp.) damage on size distribution of durum wheat (<Emphasis Type="Italic">Triticum durum</Emphasis> L.) proteins

Wholemeal samples were obtained from five durum wheat cultivars at two different bug (Eurygaster spp.) damage levels (medium and high damage). The samples were incubated (60 and 120 min) and used in size exclusion high performance liquid chromatography (SE-HPLC) analyses. The results showed that the amount of larger polymeric protein (TP1) and smaller polymeric protein (TP2) obtained from total (sodium dodecyl sulfate soluble) proteins decreased significantly in the bug-damaged samples, while the amount of total larger monomeric proteins (TP3) increased. The polymeric/monomeric protein ratio of all cultivars decreased at 60 min of incubation with increasing damage level. For all cultivars, the ratio of unextractable polymeric protein (UPP%) significantly decreased at 60 min of incubation except cv. Diyarbakir. The results suggested that bug protease caused depolymerization and/or disaggregation of polymeric proteins to lower their average molecular size. The changes in protein structure as determined using SE-HPLC supported by the decreases in gluten content and gluten index values which decreased with suni-bug damage. Deteriorative effects of bug damage on durum wheat quality were found to be quite similar to those on bread wheats.     

Morphological and dielectric properties of barium chloride‐filled poly(vinylidene fluoride) films

Morphological characteristics of poly(vinylidene fluoride) (PVDF) films, filled with mass fractions (w ≤ 20%) of Barium Chloride (BaCl₂), were investigated by X‐ray diffraction (XRD), Fourier transform infrared (FTIR) absorption spectra and differential scanning calorimetry (DSC) measurements. The dielectric properties of films were measured from 250 Hz to 1 MHz range between 100 and 400 K as a function of frequency and temperature. Spectroscopic data revealed that the filled and unfilled films include α‐, β‐, and γ‐crystalline phases. By a 20% filling, 73% increase was obtained in the total degree of crystallinity. Since the BaCl₂ formed fluorine bridges over the chain segments on the crystal lamellar surface, the γ‐crystalline phase decreased, whereas the total degree of crystallinity increased. Dielectric measurements showed that maximum of the dielectric loss factor belonging to β‐relaxation transition decreased linearly with filling level. The filling process did not have any effect on the real dielectric constant till α‐relaxation transition region. However, in the α‐relaxation transition region, it was determined that the real dielectric constant increased linearly with filling level. POLYM. COMPOS., 31:1782–1789, 2010. © 2010 Society of Plastics Engineers.     

The first catalytic hydrolysis of ethylenediamine bisborane with hydrogel-supported metallic nanoparticles

Ethylene diamine bisborane (EDB) was synthesized in a single step as the hydrogen storage material. The synthesized compound was firstly used in the literature for the production of hydrogen gas by catalytic hydrolysis reaction. Cu, Co and Ni nanoparticles with average sizes of 75–150 nm formed in p(acrylicacid-co-vinylimidazole) hydrogel network structures were used as catalysts for the hydrolysis reaction. The effect of the parameters such as catalyst type, EDB concentration, catalyst concentration, temperature and solvent environment on the catalytic hydrolysis reaction of EDB was investigated. In the activity tests for the catalyst, it was determined that the catalyst had a loss of only 15% in activity even at the end of 5 cycles. The activation energies of hydrolysis reaction were calculated as 39.42 kJmol^–1, 44.77 kJmol^–1 and 47.48 kJmol^–1 for Cu, Co and Ni hydrogel composite catalyst, respectively.     

Diagnostic value of determining hemoglobin in cerebrospinal fluid in acute cerebral circulatory disorders

The results of hemoglobin determination in the CSF by the method of fluorescence microscopy in 195 patients speaks in favor of relative diagnostical importance of hemoglobin in the supra fall-out CSF for establishing the character of the stroke. The following circumstances testify to this fact: 1) in an artificial admixture of blood in the CSF in some cases there may be hemolysis of "passing" erythrocytes; 2) in a genuine admixture of blood, tests of hemoglobin in the centrifugate of the CSF may be negative since in some cases the transition of hemoglobin into bilirubin in the subarachmoid space occurs more rapidly than the hemolysis of erythrocytes. Thus, the hemoglobin does not accumulate in the liquid in quantities, sufficient enough to be measured by the existing methods; 3) in a large amount of artificial blood admixture, even without a hemolysis of "passing" erythrocytes the hemoglobin tests in the centrifugate of the CSF may be positive at the expense of hemoglobin of the blood plasma.     

Fabrication of basalt embedded composite fiber membrane using electrospinning method and response surface methodology

In this study, a novel basalt embedded fiber membranes was prepared by the electrospinning method. The effects of the feed rate, voltage, tip to collector distance, and the basalt content on the prepared composite fiber membranes were investigated and optimized using the response surface method. Four models were built to compare the fibers in terms of deionized water flux (DWF), activated sludge flux, chemical oxygen demand (COD) removal, and porosity of fiber membranes. All the developed models were significant and adequately precise. The maximum flux of DWF was obtained when the voltage was 17.25 kV, the tip to collector distance of 19 cm, and a basalt content in polymer of 1.25%. COD removal decreased at higher voltage values as the feed rate increased. The porosity, pore size, and the contact angle values decreased for basalt embedded fiber membrane. The increases in the basalt percentage in polymer increased the hydrophilicity of the fiber. The flux decline for the basalt embedded fiber membrane was compared with the pristine fiber membrane. The permeate fluxes of pristine and basalt embedded fiber membranes were 42.3 and 59.6 L/m²/h, respectively. The biofouling performances of pristine and basalt embedded fiber membranes were also examined. Irreversible fouling decreased from 42.9% to 8.0%, and reversible fouling increased from 56.5% to 91.1% after modification of the membrane with basalt powder. Scanning electron microscopy with energy dispersive X-ray analysis (SEM–EDX) analysis showed that basalt powder was successfully embedded into polyether sulfone polymer.