synthesis of zinc dialkyldithiophosphate (zddp) consists of two stages. in the first stage, phosphorus pentasulfide reacts with an alcohol to give dialkyldithiophosphoric acid. in the second stage, the acid is neutralized by zinc oxide. in addition  to the product, some impurities are also formed which affect the quality of the final product. if we can determine the chemical structure of these ...

High-purity (SupT) and reagent-grade (ST), stoichiometric and silicate-containing α-tricalcium phosphate (α-TCP: ST0/SupT0 and Si-TCP x=0.10: ST10/SupT10) were prepared by solid-state reaction based on the substitution mechanism Ca3(PO4)(2-x)(SiO4)x. Samples were determined to be phase pure by X-ray diffraction (XRD), and Rietveld analysis performed on the XRD data confirmed inclusion of Si in ...

in this study, response surface methodology was used to determine the optimum raw sugar beet juice purification process conditions using bentonite to produce inverted liquid sugar. for this purpose, impact of factors on the purification process such as bentonite concentration (1-5 gr/li), ph (3.5-6) and temperature (35-95 ˚c) was investigated. for each response, a second-order polynomial model ...

to determine the most important traits affecting root yield and sugar content in monogerm germplasm of sugar beet, 75 monogerm f1 hybrids were evaluated in three separate experments conducted in randomized complete block desing (rcb) with four replications at abdo–al–rasoul research farm, karaj in 2004. root yield, root length, root diameter, crown height, crown diameter, sugar content, α–amino...

A method is proposed to determine trace rare earth impurities in high-purity CeO2 by HPLC combined with electrothermal vaporization inductively coupled plasma atomic emission spectrometry (ETV-ICP-AES). The chromatographic retention behaviours of the matrix (Ce) and rare earth impurities were studied using 2ethylhexyl hydrogen 2-ethylhexylphosphonate (P507) resin as the stationary phase and dil...

This study addresses the effect of impurities on the crystallization of Na2CO3 produced within a strategy for capturing CO2 from flue gases by alkaline absorption. A novel technology membrane assisted crystallization is proposed for Na2CO3 crystallization from mother liquors containing impurities. High purity of Na2CO3•10H2O crystals was obtained without impacting the performance of the mass tr...

One of the most appropriate methods for elimination of trace impurities in helium is cryogenic adsorption process. So, in this study design and construction of cryogenic adsorption helium purification system (3 Nm3.hr-1, 80 bar) carried out using activated carbon as adsorbent at 77K. To evaluation of adsorption dynamics and effect of pressure on elimination of trace impurities, helium purificat...

extensive application of silica nanoparticles (snps) in various industrial products has led to the development of silica extraction methodologies out of various waste products. rice husk is an agricultural waste with a high content of amorphous silica. however, the presence of metal ion impurities and unburned carbon in the rice husk content may present an adverse effect on product color and pu...

in order to determine the optimum sowing and harvesting dates of two autumn sugar beet cultivars (bete vulgaris l.) and develop the planting area of this crop, the present research was conducted in fasa, iran during 2005-2008. the experiment was carried out in split-split plots based on randomized complete block design (rcbd) with four replications. three sowing dates (september 27, october 17 ...

While developing a liquid argon detector for dark matter searches we investigate the influence of air contamination on the VUV scintillation yield in gaseous argon at atmospheric pressure. We determine with a radioactive αsource the photon yield for various partial air pressures and different reflectors and wavelength shifters. We find for the fast scintillation component a time constant τ1 = 1...