A. S. Kipcak

Characteristics of Thin-layer Infrared Drying of Green Bean

Doymaz I., Kipcak A.S., Piskin S. (2015): Characteristics of thin-layer infrared drying of green bean. Czech J. Food Sci., 33: 83–90. The effect of infrared (IR) power on drying kinetics, rehydration, and colour of green beans was investigated. The drying experiments were carried out at 83, 104, 125, 146, 167, and 188 W. It is observed that drying characteristics, rehydration, and colour of bean slices were greatly influenced by infrared power. The drying data were fitted with five thin-layer drying models available in the literature. Results showed that Midilli et al. and Aghbashlo et al. models are superior to the other models for explaining the drying kinetics of green bean slices. Effective moisture diffusivity was calculated in the range of 6.57 × 10–10 to 4.49 × 10–9 m2/s. Activation energy was estimated by a modified Arrhenius type equation and found to be 11.379 kW/kg.

Characterization of some boron minerals against neutron shielding and 12 year performance of neutron permeability

In this study, the nuclear radiation permeability properties of various boron minerals are evaluated because of their high neutron absorption and lowest transmission properties. Because of these properties boron minerals can be used at the area of neutron shielding. X-ray diffraction (XRD) analyses are done for the identification of the minerals, and then their B2O3 contents are determined experimentally. In addition, X-ray florescence (XRF) analyses are made for quantitative determination of calcium, iron, zinc and arsenic contents. The methods of Differential Thermal Analysis, Thermal Gravimetry (TG/DTA) and Differential Scanning Calorimeter (DSC) are used for obtaining the enthalpy and weight changes with temperature. Additionally, neutron permeability experiments are conducted. From the experimental results, the highest boron oxide content was found in clay containing colemanite. Iron, zinc and arsenic contents were not affecting the neutron shielding. The lowest permeability is provided by the kurnakovite mineral. Also it is observed that all of the minerals show an increase in their permeability in 12 years. It can be stated that boron minerals, specifically kurnakovite, is determined to yield the lowest neutron permeability value and therefore, the use of these materials for neutron shielding would be suitable.

The Synthesis and Physical Properties of Magnesium Borate Mineral of Admontite Synthesized from Sodium Borates

Magnesium borates are significant compounds due to their advanced mechanical and thermal durability properties. This group of minerals can be used in ceramic industry, in detergent industry, and as neutron shielding material, phosphor of thermoluminescence by dint of their extraordinary specialties. In the present study, the synthesis of magnesium borate via hydrothermal method from sodium borates and physical properties of synthesized magnesium borate minerals were investigated. The characterization of the products was carried out by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and Raman spectroscopies, and differential thermal analysis and thermal gravimetry (DTA/TG). The surface morphology was examined by scanning electron microscopy (SEM). B2O3 content was determined through titration. The electrical resistivity/conductivity properties of products were measured by Picoammeter Voltage Source. UV-vis spectrometer was used to investigate optical absorption characteristics of synthesized minerals in the range 200–1000 nm at room temperature. XRD results identified the synthesized borate minerals as admontite [MgO(B2O3)3·7(H2O)] with code number “01-076-0540” and mcallisterite [Mg2(B6O7(OH)6)2·9(H2O)] with code number “01-070-1902.” The FT-IR and Raman spectra of the obtained samples were similar with characteristic magnesium borate bands. The investigation of the SEM images remarked that both nano- and microscale minerals were produced. The reaction yields were between 75.1 and 98.7%.

Effect of Magnesium Borates on the Fire-Retarding Properties of Zinc Borates

Magnesium borate (MB) is a technical ceramic exhibiting high heat resistance, corrosion resistance, great mechanical strength, great insulation properties, lightweightness, high strength, and a high coefficient of elasticity. Zinc borate (ZB) can be used as a multifunctional synergistic additive in addition to flame retardant additives in polymers. In this study, the raw materials of zinc oxide (ZnO), magnesium oxide (MgO), and boric acid (H3BO3) were used in the mole ratio of 1 : 1 : 9, which was obtained from preexperiments. Using the starting materials, hydrothermal synthesis was applied, and characterisation of the products was performed using X-Ray diffraction (XRD) and Fourier transform infrared (FT-IR) and Raman spectroscopies. The forms of Zn3B6O12·3.5H2O, MgO(B2O3)3·7(H2O), and Mg2(B6O7(OH)6)2·9(H2O) were synthesised successfully. Moreover, the surface morphology was investigated using scanning electron microscopy (SEM), and the B2O3 content was determined. In addition, the reaction yields were calculated. The results of the B2O3 content analysis were in compliance with the literature values. Examination of the SEM images indicated that the obtained nanoscale minerals had a reaction efficiency ranging between 63–74% for MB and 87–98% for ZB. Finally, the fire-retarding properties of the synthesised pure MBs, pure ZBs, and mixtures of MB and ZB were determined using differential thermal analysis and thermal gravimetry (DTA-TG) and differential scanning calorimetry (DSC).

Magnesium Borate Synthesis by Microwave Energy: A New Method

Magnesium borates are one of the major groups of boron minerals that have important properties such as high heat and corrosion resistances and high coefficients of elasticity. In this study, magnesium borate minerals are synthesized using boric acid and magnesium oxide with a new method of microwave, and the synthesized minerals are characterized by various analysis techniques. The results show that pure, “magnesium borate hydrate” minerals are obtained at the end of various steps. The characterization of the products is determined with the techniques of X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Raman Spectroscopy, and Scanning Electron Microscopy (SEM). Additionally, overall “magnesium borate hydrate” yields are calculated and found about 67% at 270 W, 8 minutes and 360 W, 3 minutes of reaction times, respectively.

Modeling and Investigation of the Swelling Kinetics of Acrylamide-Sodium Acrylate Hydrogel

The acrylamide-sodium acrylate hydrogel was synthesized by free radical polymerization of the method of solution polymerization. Dynamic swelling tests were conducted at 25, 40, and 60°C temperatures, in order to investigate the swelling properties of the synthesized hydrogel. The results have shown that swelling content and swelling rate of the hydrogel increase with increasing the swelling water temperature. The diffusivity values changed from to m2 s−1 over the temperature range. The activation energies were found as 3.56, 3.71, and 3.86 kJ mol−1 at 25, 40, and 60°C, respectively. The experimental drying curves obtained were fitted to a three different models, namely, Peleg’s, first-order absorption kinetic, and exponential association equation models. All the models applied provided a good agreement with the experimental data with high values of the coefficient of determination (), the least values of the reduced chi-square (), and root mean square error (RMSE). Comparing the determination of coefficient, reduced chi-square, and root mean square error values of three models, it was concluded that the exponential association equation model represents swelling characteristics better than the others.

Characterization and Neutron Shielding Behavior of Dehydrated Magnesium Borate Minerals Synthesized via Solid-State Method

Magnesium borates are one of the major groups of boron minerals that have good neutron shielding performance. In this study, dehydrated magnesium borates were synthesized by solid-state method using magnesium oxide (MgO) and boron oxide (B2O3), in order to test their ability of neutron shielding. After synthesizing the dehydrated magnesium borates, characterizations were done by X-ray Diffraction (XRD), fourier transform infrared (FT-IR), Raman spectroscopy, and scanning electron microscopy (SEM). Also boron oxide (B2O3) contents and reaction yields (%) were calculated. XRD results showed that seven different types of dehydrated magnesium borates were synthesized. 1000°C reaction temperature, 240 minutes of reaction time, and 3 : 2, 1 : 1 mole ratios of products were selected and tested for neutron transmission. Also reaction yields were calculated between 84 and 88% for the 3 : 2 mole ratio products. The neutron transmission experiments revealed that the 3 : 2 mole ratio of MgO to B2O3 neutron transmission results (0.618–0.655) was better than the ratio of 1 : 1 (0.772–0.843).

Characterization and physical properties of hydrated zinc borates synthesized from sodium borates

Abstract In this study, Zn3B6O12·3.5H2O, a type of a zinc borate hydrate, was synthesized from the sodium borate mineral Na2B4O7·5H2O. Two different zinc sources, i.e. ZnSO4·7H2O and ZnCl2, were used in the hydrothermal synthesis. Products were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. Product morphologies were studied using scanning electron microscopy (SEM). Then optical absorption characteristics and electrical properties were investigated. Based on these results, Zn3B6O12·3.5H2O was obtained under many synthetic conditions as a single phase with high reaction efficiencies and sub-micrometer (100 nm to 1 μm) particle sizes. The electrical resistivity and optical energy gap were found as 8.8×1010 Ω cm and 4.13 eV, respectively. The novelty obtained in this study is the synthesis of zinc borate hydrate compound with high crystallinity without using any modification agent or organic solvent.

A low-temperature, environment-friendly approach to the synthesis of magnesium borates using magnesium waste scraps

Abstract In the present study, magnesium borate synthesis was performed by a hydrothermal mixing method, with the use of magnesium waste scraps (W) as the magnesium source, along with boric acid (H) or boron oxide (B) as the boron source. For an environment-friendly approach, a solid waste of magnesium was used at low reaction temperatures. Results of X-ray diffraction analyses showed that admontite [MgO(B2O3)3·7(H2O)] and mcallisterite [Mg2(B6O7(OH)6)2·9(H2O)] types of magnesium minerals were obtained from the synthesis. Through Fourier transform infrared spectroscopy and Raman spectroscopy, in both the infrared and the visible regions, characteristic borate bands were observed. The results of the boron oxide content analyses were in agreement with literature data. The particle sizes, obtained by scanning electron microscopy analyses, were found within the range of 200 nm to 2 μm for mcallisterite and 210 nm to 2.5 μm for admontite minerals. The reaction yields of the minerals were calculated in the range of 16.6–82.0% for the experiments on waste magnesium and boric acid, whereas for the experiments on waste magnesium and boron oxide these were 12.7–78.8%.

Characterisation and determination of the neutron transmission properties of sodium–calcium and sodium borates from different regions in Turkey

In this study, ulexite, probertite found within sodium–calcium borates and borax, and tincalconite found within sodium borates retrieved from different regions in Turkey are evaluated for their neutron irradiation performances. Characterisations were performed using XRD, FT-IR, Raman spectroscopy. B2O3 contents were determined experimentally, structural water contents and surface morphologies were determined using DTA/TG and SEM. Neutron transmission values and total macroscopic cross-sections were determined using 239Pu–Be source moderated in a howitzer. Neutron transmission values from lowest to highest were found to be as follows: secondary ulexite (Kırka), tincalconite (Kırka), ulexite (Kestelek), ulexite (Kırka), borax (Kırka), probertite (Kestelek) and ulexite (Bigadiç).