Thermal decomposition behavior of tobacco stem Part II: Kinetic analysis

As a continuation of the previous study on the thermal degradation behavior of tobacco stem, this work is focused on the kinetics of pyrolytic decomposition. Thermogravimetric analysis of tobacco stem samples was conducted under nitrogen atmosphere at different heating rates of 5, 10, 15, and 20°C/min at a temperature range of 25–1,000°C. The kinetic parameters, such as activation energy, pre-exponential factor, and reaction order, were determined by applying the Coats–Redfern method for the main pyrolysis occurred in the second zone by means of the decomposition of hemicellulose, cellulose, and lignin at a temperature range 180–540°C. In addition, the activation energy was calculated using various degradation models, including Kissinger, Friedman (FR), Flynn–Wall–Ozawa (FWO), and Kissinger–Akahira–Sunose (KAS). The average activation energy of tobacco stem was calculated to be 150.40, 230.76, 216.97, and 218.56 kJ/mol by the Kissinger, FR, FWO, and KAS models, respectively.     

Food Technological Applications for Optimal Nutrition: An Overview of Opportunities for the Food Industry

Abstract: An increasingly important determinant in food choice is the growing consumer concern about nutrition and health. This focusing of consumer interest on the food supply, and also extensive research and technological developments in food science will provide further opportunities for new product development. The Food‐Based Dietary Guidelines of the World Health Organization (WHO) and European Union (EU) legislation on health claims play an important role in regulating information to the public about a wholesome diet and for improving the availability and affordability of nutritious food choices to consumers. More specifically, the food industry can contribute by reducing the number of energy‐dense products; by improving the nutrient profile of processed food through the reduction of salt, added sugar, trans‐fatty acid, and saturated fat content. As a result, food science and technology are prompted to create a new framework for these food‐based dietary guidelines, principally in the areas of food physics, methods of food storage and preservation, nutrient restoration and fortification of foods, and the development of health‐focused designer foods and functional foods. The aim of this review is to provide an overview of some further opportunities for new product development and nutrition research. Some topics related to the energy reduction of foods include: dilution and structure design, carbohydrate and/or fat substitutes, and inhibition of enzymes in carbohydrate and/or fat digestion; additionally, regulation of some metabolic functions with food‐derived bioactive peptides and probiotics, and enrichment of foods with bioactive compounds are reviewed in this overview as the most promising issues.     

Effects of Polymerization and Briquetting Parameters on the Tensile Strength of Briquettes formed from Coal Coke and Aniline-Formaldehyde Resin

In this work, the utilization of aniline (C₆H₇N) formaldehyde (HCHO) resins as a binding agent of coke briquetting was investigated. Aniline (AN) formaldehyde (F) resins are a family of thermoplastics synthesized by condensing AN and F in an acid solution exhibiting high dielectric strength. The tensile strength sharply increases as the ratio of F to AN from 0.5 to 1.6, and it reaches the highest values between 1.6 and 2.2 F/AN ratio; it then slightly decreases. The highest tensile strength of F-AN resin-coke briquette (23.66 MN/m²) was obtained from the run with 1.5 of F/AN ratio by using (NH₄)₂S₂O₈ catalyst at 310 K briquetting temperature. The tensile strength of F-AN resin-coke briquette slightly decreased with increasing the catalyst percent to 0.10%, and then it sharply decreased to zero with increasing the catalyst percent to 0.2%. In general, the tensile strength of F-AN resin-coke briquette increased as increased the briquetting temperature in these tests contras with NaOH catalytic runs. The effect of pH on the tensile strength is irregular. As the pH of the mixture increases from 9.0 to 9.2, the tensile strength shows a sharp increase, and the curve reaches a plateau value between pH 9.3 and 9.9; then the tensile strength shows a slight increase after pH = 9.9.     

CdO/Cu2O solar cells by chemical deposition

CdO and Cu₂O thin films have been grown on glass substrates by chemical deposition method. Optical transmittances of the CdO and Cu₂O thin films have been measured as 60–70% and 3–8%, respectively in 400–900 nm range at room temperature. Bandgaps of the CdO and Cu₂O thin films were calculated as 2.3 and 2.1 eV respectively from the optical transmission curves. The X-ray diffraction spectra showed that films are polycrystalline. Their resistivity, as measured by Van der Pauw method yielded 10⁻²–10⁻³ Ω cm for CdO and approximately 10³ Ω cm for Cu₂O. CdO/Cu₂O solar cells were made by using CdO and Cu₂O thin films. Open circuit voltages and short circuit currents of these solar cells were measured by silver paste contacts and were found to be between 1–8 mV and 1–4 μA.     

Molybdenum- and vanadium-containing perovskite electrocatalysts for dissociation of H2S

Catalytic operations, achieving considerable energy savings, continue getting wider application especially in clean energy systems. Perovskite materials, owing to their chemical and thermal stability, can be conveniently used as catalysts and electrode materials at wide temperature ranges. Hydrogen sulfide (H₂S) offers a new and abundant source of hydrogen, the ultimate energy carrier. In the present work, change in electrical conductivity of catalysts obtained by adding molybdenum (Mo) and vanadium (V) as B to the perovskite structure with lanthanum (La) and strontium (Sr) as A and A′, respectively, has been studied within a temperature range of up to 1100 K. Samples La_0.75Sr_0.25MoO₃ and LaSr_0.5V_0.5O₃ demonstrated the highest values of conductivity at 1100 K. At lower temperatures, Cr-added Mo and V catalysts La_0.9Sr_0.1Cr_0.5Mo_0.5O₃ and La_0.9Sr_0.1Cr_0.5V_0.5O₃ had higher conductivity, closely followed by LaSr_0.5V_0.5O₃.     

Incidence of Fusarium verticillioides and levels of fumonisin B1 and B2 in corn in Turkey

A total of 100 corn samples conforming collected from local farmers and markets from districts of Samsun, Turkey, were analyzed for Fusarium verticillioides, fumonisin B₁ and B₂ contamination. Ninety-three corn samples were found to contain F. verticillioides, 52 samples fumonisin B₁, and 25 samples fumonisin B₂. Fumonisin B₁ contamination ranged from 0.05 to 25.72 mg/kg and B₂ from 0.05 to 5.7 mg/kg, respectively. This figure indicated widespread contamination of fumonisin B₁ and B₂ in maize grown in different areas of Samsun, Turkey.     

Practical realisation of ozone clearing after disperse dyeing of polyester

In this study, a novel system utilising ozone in jet dyeing machines is introduced, and the results of ozone‐clearing treatments of disperse dyed polyester on the prototype modified machine are reported. A Venturi injector was mounted on the liquor circulation pipe of the jet dyeing machine to feed ozone gas into the machine. Ozone was generated via an ozone generator by feeding conditioned air into the generator. The ozone gas entering the pipe partly dissolved in the treatment liquor; the dissolved portion and the gaseous ozone interacted via the fabric in the pipe, especially in the nozzle and also at the bottom of the autoclave (machine body). Disperse dyed polyester fabrics of textile‐company mass production were ozone cleared in this prototype. Ozone clearing was achieved in cold water (room temperature), and no other chemicals were used. The colour of the samples, wet fastness properties, and the chemical oxygen demand of the effluent were investigated, and costs were compared with those of conventional reduction clearing of ozone. Results were outstanding: an 83% cost reduction, 67% timesaving, and an 88% COD reduction were achieved.     

Fenton and Fenton‐like oxidation of CI Basic Yellow 51: a comparative study

When ferric ions are substituted for ferrous ions in Fenton’s reagent, the reactions which occur are called Fenton‐like reactions. This study describes the relative efficiency of Fenton (with ferrous ions) and Fenton‐like (with ferric ions) reactions for the degradation of a basic dyestuff, CI Basic Yellow 51, in aqueous solution. Comparisons were made on the basis of the observed reductions in chemical oxygen demand and visible absorption of the dye solutions at optimum reaction conditions. It was found that the Fenton process with 2.63 mm ferrous ion and 39.96 mm hydrogen peroxide at the optimum pH (3.0) eliminated 92.2% of chemical oxygen demand and 98.9% of colour in 22 min, whereas 43.2% of chemical oxygen demand and 64.6% of colour was eliminated by the Fenton‐like process within the same time period, but at pH 4. The efficiency of the latter was significantly improved (to 96.6% removal of colour and 99.7% removal of chemical oxygen demand) by an increase in temperature of 35 °C (from 15 to 50 °C), while no improvements were observed in the efficiency of the Fenton process by temperature elevations.