Preparation and characterization of poly(acrylic acid)/pillared clay superabsorbent composite

Pillared clay-based superabsorbents (PILC-SA) were synthesized by using Al pillared-montmorillonite K10 and KSF via graft copolymerization reaction of acrylic acid (AA). Swelling behavior of pillared clay-based superabsorbent films in distilled water and at different pH values were investigated at room temperature. It was also obtained that Al-KSF and Al-K10 based superabsorbents were pH dependent and showed a reversible swelling behavior. Water absorbency of Al-KSF based superabsorbent was higher than that of Al-K10 based one. SEM, FTIR, and XRD analysis were conducted for further characterization of the PILC-SA. FTIR analyses lead to ester formation between PILC and SA. XRD revealed the basal spacing of the pillared clays before and after in situ incorporation indicating that the morphology of the superabsorbent was exfoliated and the layers of clay dispersed on the composite.     

Printable and Flexible Phototransistors Based on Blend of Organic Semiconductor and Biopolymer

Printable and flexible organic phototransistors (OPTs) make comprehensive requirements for the organic semiconductors (OSCs), including high photosensitivity, decent transistor characteristics, appropriate solution viscosity, and good film flexibility. It has been challenging to obtain such semiconductors. Here, we demonstrated that by taking advantage of the interfacial charge effect, printable and flexible OPTs with high performance can be successfully fabricated through simply blending common OSCs with polymers. Using 2,7‐dioctyl[1]benzothieno[3,2‐b][1]benzothiophene and an insulating biopolymer polylactide, OPTs with blended and layered structure are both fabricated and investigated. The photoresponses of the OPTs can be modulated by gate voltage over 1000 times, and their responsivities are measured up to 400 A W^?1. As compared to the layered OPTs, the blended ones exhibit higher photocurrent to dark current ratio (up to 10⁵) and better light detection limit (lower than 0.02 mW cm^?2). The improvements are attributed to larger interfacial area and more intensive charge trapping effect. The flexible OPTs are further fabricated by inkjet printing the blended solution. This work presents OPTs with comprehensive advantages including low cost, enhanced photosensitivity, great flexibility, and printability, which are realized by simply blending common OSC with polymer, and thus provide an inspiration for the design of novel organic electronics.     

Emissions estimation for lignite-fired power plants in Turkey

The major gaseous emissions (e.g. sulfur dioxides, nitrogen oxides, carbon dioxide, and carbon monoxide), some various organic emissions (e.g. benzene, toluene and xylenes) and some trace metals (e.g. arsenic, cobalt, chromium, manganese and nickel) generated from lignite-fired power plants in Turkey are estimated. The estimations are made separately for each one of the thirteen plants that produced electricity in 2007, because the lignite-fired thermal plants in Turkey are installed near the regions where the lignite is mined, and characteristics and composition of lignite used in each power plant are quite different from a region to another. Emission factors methodology is used for the estimations. The emission factors obtained from well-known literature are then modified depending on local moisture content of lignite. Emission rates and specific emissions (per MWh) of the pollutants from the plants having no electrostatic precipitators and flue -gas desulfurization systems are found to be higher than emissions from the plants having electrostatic precipitators and flue -gas desulfurization systems. Finally a projection for the future emissions due to lignite-based power plants is given. Predicted demand for the increasing generation capacity based on the lignite-fired thermal power plant, from 2008 to 2017 is around 30%.     

Profiles of Organic Acid and Volatile Compounds in Acid-Type Cheeses Containing Herbs and Spices (Surk Cheese)

A study was conducted to evaluate the basic chemical composition, organic acids, volatile compound profiles, and overall acceptability of Surk cheese (acid cheese). The organic acids were determined by reverse phase high performance liqued chromatography method, and volatile compounds were analyzed by static headspace/gas chromatography/mass spectrometry technique. A total of 134 volatile compounds, including 42 esters, 40 terpenes, 15 alcohos, 11 free fatty acids, 6 ketones, 5 aldehydes, 4 alkenes, 4 phenyl propanoids, 3 phenolics, and 4 other compounds, were identified in the Surk cheeses. The main compounds were found to be carvacrol, γ-terpinene, p-cymene, hexanoic acid, octanoic acid, decanoic acid, butanoic acid, and eugenol. The mean total organic acid content of the Surk cheese was 1.71 g/100 g. The main organic acid in the Surk cheese was lactic acid (1067 mg/100 g), followed by acetic, propionic, oxalic, formic, citric, pyruvic, orotic, hippuric, and uric acids.     

Modified Atmosphere Packaging of “Napoleon” Cherry: Effect of Packaging Material and Storage Time on Physical,Chemical, and Sensory Quality

Effects of modified atmosphere and polymeric packaging material on the physical (mass loss, color, firmness), chemical (pH, total titratable acidity, total soluble solid, total phenolic content, total anthocyanin content), and sensory quality of “Napoleon” cherry (Prunus avium L. “Napoleon”) were studied. While lightness (L*) remained fairly unchanged, redness (a*), yellowness (b*), and chroma (C*) decreased during a 42-day storage period, resulting in darker fruit. Firmness did not differ significantly from the initial values (P ≤ 0.05) after 42 days of storage at 0°C. pH increased for all treatments over the storage period. In general, total titratable acidity increased during the first 2 weeks, and then decreased afterwards. Packaging significantly reduced mass losses, which were 24.08%, 0.50%, 0.39%, and 0.81% for control (unpackaged), polypropylene tray/biaxially oriented polypropylene film (PP/BOPP), polypropylene tray/cast polypropylene film, and polyvinyl chloride-polyethylene tray/polyethylene terephthalate-polyethylene films, respectively. Modified atmosphere packaging was found beneficial on extending the shelf life of fruit during storage. The shelf life of “Napoleon” cherries was suggested as 28 days for packaged samples and 14 days for unpackaged samples at 0°C. Samples packaged with PP/BOPP under 21% O₂ 79% N₂ preserved their physical, chemical, and sensory quality better than other treatments.     

Efficiency of Structural Materials in Sustainable Design

The main aim of this paper is to investigate energy consumptions, CO2 emissions and costs during the production and life cycle of structural materials. The virgin and recycled metals as well as waste minerals such as fly ash, slag in concrete save energy consumption, CO2 emissions and costs. The importance and effectiveness of recycled materials will be statistically evaluated via energy consumption, carbon footprint, ultimate strength and their ratios. Embodied energy to ultimate strength or embodied carbon to ultimate strength ratios may emphasize the effectiveness of a sustainable material. The analyses in this study indicate the utilization of the recycled steel and C50 concrete with 50% fly ash or slag is the most efficient way of using sustainable materials.     

Influence of antioxidant rich fresh vegetable juices on starch induced postprandial hyperglycemia in rats

This research analyzed the major chemical components and multiple antioxidant activities present in the fresh juice of eight vegetables, and studied their influence on starch induced postprandial glycemia in rats. A SDS-PAGE based protein fingerprint of each vegetable juice was also prepared. The yields of juice, chemical components like total proteins, total polyphenols, total flavonoids, total anthocyanins and free radicals like the ABTS˙(+) cation, DPPH, H(2)O(2), scavenging activities and reducing properties for NBT and FeCl(3) showed wide variations. Vegetable juice from brinjal ranked first in displaying total antioxidant capacity. Pretreatment of rats with vegetable juices moderated starch induced postprandial glycemia. The fresh juice from the vegetables ridge gourd, bottle gourd, ash gourd and chayote significantly mitigated postprandial hyperglycemic excursion. Total polyphenol concentrations present in vegetable juices positively influenced ABTS˙(+) scavenging activity and total antioxidant capacity. However, NBT reducing activity of juices was positively affected by total protein concentration. Contrarily, however, high polyphenol content in vegetable juice was observed to adversely affect the postprandial antihyperglycemic activity of vegetable juices. This is the first report exploring antihyperglycemic activity in these vegetable juices and highlights the possible adverse influence of high polyphenol content on the antihyperglycemic activity of the vegetable juices.     

Metabolic activities of Lactobacillus spp. strains isolated from kefir

A total of 21 strains of Lactobacillus species were isolated from Turkish kefir samples, in order to select the most suitable strains according to their metabolic activities including probiotic properties. As a result of the identification tests, 21 Lactobacillus isolates were identified as L. acidophilus (4%), L. helveticus (9%), L. brevis (9%), L. bulgaricus (14%), L. plantarum (14%), L. casei (19%) and L. lactis (28%). The amount of produced lactic acid, hydrogen peroxide, proteolytic activity, and acetaldehyde productions of Lactobacillus spp. were determined. Different amounts of lactic acid were produced by strains studies; however, lactic acid levels were 1.7-11.4 mg/mL. All strains produced hydrogen peroxide. L. bulgaricus Z14L strain showed no proteolytic activity, L. casei Z6L strain produced the maximum amount (0.16 mg/mL) of proteolytic activity. Acetaldehyde concentration produced in Lactobacillus strains ranged between 0.88-3.52 microg/mL.