Calcium carbonate and ammonium polyphosphate flame retardant additives formulated to protect ethylene vinyl acetate copolymer against fire: Hydrated or carbonated calcium?

In this study, the effect of the chemical nature of different calcium (Ca)-based minerals as flame retardant additives in combination with ammonium polyphosphate (APP), in 1:1 proportions, on the flame retardancy behavior and performance of ethylene vinyl acetate copolymer was discussed. Combining APP with partly and completely hydrated calcium oxide led to superior flame-retardant function detected in mass loss calorimeter measurements with respect to the corresponding system containing carbonated calcium. This privileged character was attributed to the higher reactivity of hydrated Ca-based fillers toward APP in comparison with Ca carbonate, which induced the formation of an intumescent residue. The difference between reactivity potential of hydrated and dry Ca was demonstrated by the newly formed thermally stable species, and further evidenced by thermogravimetric analysis performed on APP/fillers blends. Moreover, the presence of more crystalline domains in the Ca/phosphorus-based compounds was evidenced by XRD analysis of the mass loss calorimeter test residues. The results of this work highlight the role of blend additive systems on the performance of flame retardancy of polymer materials.     

Formation of OTS self-assembled monolayers at chemically treated titanium surfaces

Enhanced biocompatibility of titanium implants highly depends on the possibility of achieving high degrees of surface functionalization for a low immune response and/or enhanced mineralization of bioactive minerals, such as hydroxyapatite. In this respect, surface modification with Self Assembled Monolayers (SAMs) has a great potential in delivering artificial surfaces of improved biocompatibility. Herein, the effectiveness of common chemical pre-treatments, i.e. hydrogen peroxide (H₂O₂) and Piranha (H₂SO₄ + H₂O₂), in facilitating surface decontamination and hydroxylation of titanium surfaces to promote further surface functionalization by SAMs is investigated. The quality of the octadecyltrichlorosilane (OTS) based SAM appeared to strongly depend upon the surface morphology, the density and nature of surface hydroxyl sites resulting from the oxidative pre-treatments. Contrary to common belief, no further hydroxylation of the titanium substrate was observed after the selected chemical pre-treatments, but the number of hydroxyl groups available on the surface was decreased as a result of the formation of a titanium oxide layer with a gel-type structure. Further examinations by atomic force microscopy, infrared spectroscopy and X-ray photoelectron spectroscopy also revealed that mild oxidizing conditions were sufficient to remove surface contamination without detrimental effects on surface hydroxylation state and surface roughness. Furthermore, the adsorption of the alkylsiloxane molecules forming the SAM film is believed to proceed through hydrolysis at surface acidic hydroxyl groups rather than randomly. This site dependent adsorption process has significant implications for further functionalization of titanium based implants. It also highlights the difficulty of achieving an OTS based SAM at the surface of titanium and question the quality of SAMs reported at titanium surfaces so far.     

Optimal thermodynamic and economic volume of a heat recovery steam generator by constructal design

The ratios of gas flow to steam flow are huge in heat recovery steam generators (HRSGs) compared to other steam generators. So the volume which is occupied by components of the HRSG such as economizer, evaporator and superheater is important factor when the HRSG is applied in structures including buildings and ships. The optimum volume of a HRSG is deduced through optimization of entropy generation and cost evaluation. By increasing volume, second law of thermodynamics is improved, but this improvement may not be economical. In this work, the best dimensions and arrangements of flows in HRSG are obtained by constructal design and the optimization method is algorithm genetic. In this case, super heater temperature, pinch point, water/steam flow rate and gas pressure drop are derived from configuration which designed by constructal theory for HRSG. The effects of gas flow rate and inlet gas temperature are examined on the values of optimum volume.     

Extraction of inulin from Burdock root (Arctium lappa) using high intensity ultrasound

Burdock root could be a source of inulin, but scarce studies about its extraction exist. To optimise conventional and ultrasound‐assisted extraction of inulin, various combinations were used. The independent variables for ultrasound extraction were sonication amplitude (20–100%), sonication temperature (20–60 °C) and sonication time (5–25 min) while for conventional extraction the following variables were water to solid ratio (5–15 v/w), temperature (40–90 °C) and time (5–40 min). For each response, a second‐order polynomial model was developed using multiple linear regression analysis. The use of high intensity ultrasound significantly improves the extraction of inulin contained within the body of Burdock root. It was shown that increasing the amplitude (from 20% to 85%) and extraction time increased the extraction yield; however, the effect of temperature was minor. Optimum extraction condition was found to be sonication time: 25 min, sonication amplitude 83.22% and temperature: 36.76 °C.     

Peanut and cardiovascular disease risk factors: A systematic review and meta-analysis

Abstract

Several studies have been conducted on the effects of peanut consumption on cardiovascular diseases (CVD) risk factors. However, the findings are conflicting and appear inconsistent. The aim of this review is to summarize the findings on the effect of peanut consumption on the risk factors of CVDs. We used relevant keywords and searched through PubMed, Scopus and Web of Science for articles published studies up to November 2018. Randomized controlled trials (RCTs) were included in this meta-analysis. Random or fixed-effects meta-analysis method depending on the results of heterogeneity tests was used to estimate the effect size. Between-study heterogeneity was assessed by Q test and I² index. Subgroup analysis was conducted to find any excess relationship. Publication bias was checked by Egger’s test and funnel plot. Quality of studies was assessed by the Cochrane criteria. According to the results of 13 RCTs, peanuts has no significant effect on weight (WMD: ?0.11?kg, P?=?0.773), waist circumference (WMD: ?1.41?cm, P?=?0.139), body mass index (WMD: ?0.14?kg/m², P?=?0.428), systolic and diastolic blood pressure (WMD: ?0.09?mmHg, P?=?0.939 and WMD: 0.60?mmHg, P?=?0.652, respectively), low-density lipoprotein cholesterol (WMD: ?3.31?mg/dl, P?=?0.472), triglyceride (WMD: ?7.59?mg/dl, P?=?0.180), total cholesterol (WMD: 3.15?mg/dl, P?=?0.171), fasting blood sugar (WMD: 0.57?mg/dl, P?=?0.604) and serum insulin (WMD: ?0.40, P?=?0.582). Also, this meta-analysis showed that peanut had a positive significant effect on high-density lipoprotein cholesterol (HDL) (WMD: 2.72?mg/dl, P?=?0.001). Peanuts consumption has a positive significant effect on HDL especially at the type of peanut oil, high-oleic peanut and peanut sprout and in healthy subjects and for consumption more than 12?weeks, while has no significant effect on other CVD risk factors.