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1.
Kanit Krisnangkura 《Journal of the American Oil Chemists' Society》1991,68(1):56-58
Equations were developed for the estimation of gross heat of combustion (HG) of triglycerides (TGs) and fatty acid methyl
esters (FAMEs) from their saponification number (SN) and iodine value (IV). HG of TG=1,896,000/SN − 0.6 IV — 1600 and HG of
FAME=618,000/SN − 0.08 IV — 430. When these equations were tested on cottonseed oil, soybean oil, partially hydrogenated soybean
oil, peanut oil, sunflower oil, sunflower oil methyl esters, soybean oil methyl esters and cottonseed oil methyl esters, predicted
HG values agreed well with those reported in the literature. 相似文献
2.
A thermodynamic model is proposed for the determination of kinematic viscosities of saturated fatty acid methyl esters (FAMEs) of various chain lengths at different temperatures. The linearity of the natural logarithm of viscosity-carbon number, plot is limited to a narrow carbon number range. The predicted viscosities of FAMEs of C12:0-C18:0, which are commonly found in vegetable oils and used as biodiesels, agree well with the experimental values. The highest difference is 0.354 cSt (5.60%), for methyl stearate at 40 °C. When the proposed method for viscosity calculation of saturated FAMEs are used in combination with the methods for viscosities of biodiesel the mixtures, the predicted viscosities agree well with the values reported in the literatures and the measured values. The differences between the predicted viscosities and those reported in the literatures (at 40 °C) are 1.08 to 8.56% (for eight different vegetable oil methyl esters). The differences between the predicted viscosities and the measured values for coconut methyl esters, at 25, 40 and 50 °C are 9.20, 5.53 and 5.57%, respectively. The differences are slightly higher than those of palm oil methyl esters (4.48, 2.06 and 2.48%, respectively).The proposed method can also be applied to predict the viscosities of free fatty acids and it is speculated it may be applied to other homologous series as well. 相似文献
3.
This paper presents a set of regression models which incorporates concrete and steel types in modeling the costs of office buildings. To these ends, three typical office buildings with seven and 15 stories have been designed by the help of a commercial software taking into account the Turkish practice. In each project C-16, C-20, C-25, C-30 and C-35 concrete classes and S-220 and S-420 steel types were used for dimensioning purposes. Rough construction costs were then calculated for different combinations of concrete classes and steel types. The findings of the study revealed that column dimensions decrease following an increase in a particular concrete class. However, this decrease stops after C-30. Furthermore, an average cost difference of 16% was observed between the steel types S-220 and S-420. 相似文献
4.
In this study, the change in the load-bearing system cost of a reinforced concrete office building has been investigated in relation to the earthquake regions and soil types. Three different office projects each with five stories were investigated. The structural design calculations have been made according to four different soil types and four different earthquake regions. According to each combination, concrete, steel and formwork adopted approximations were calculated to reach the rough cost of each office building. The changes in the cost of projects according to the soil type and earthquake region were examined with multiple regression analysis and analysis of variance. In general, the change in cost has been observed around 22% between first and fourth soil type and 14% between first and fourth earthquake region. 相似文献
5.
Supathra Lilitchan Cholticha Tangprawat Kornkanok Aryusuk Sumalee Krisnangkura Salisa Chokmoh Kanit Krisnangkura 《Food chemistry》2008
Total lipids and γ-oryzanol in rice bran were determined by a partial extraction method. The results agreed well with the conventional total extraction methods. The proposed method uses fewer hazardous organic solvents, takes a shorter extraction time and requires no special extraction apparatus. Total lipids and γ-oryzanol in nine rice bran varieties were analysed by the developed technique. Daw Dum 5647 had the highest total lipids and γ-oryzanol while the lowest content was found in KD XBT 313-19-1-1 and SP XBT 43-7, respectively. The adsorption coefficient (Kd) of the lipids and γ-oryzanol, between hexane and bran, at 30 °C are between 1.16 and 2.00 and 2.02 and 2.65, respectively (depending on the moisture content of the bran). From the Kd values, it was estimated that about 92–95% of the lipids and 95–96% of the γ-oryzanol were extracted into hexane at a 10:1 (v/w) ratio of hexane to bran. The effect of solvents on the extraction of γ-oryzanol from rice bran was also studied. It was found that isopropanol was the most suitable solvent for extraction and determination of γ-oryzanol in rice bran. It showed better agreement with the total extraction method. 相似文献
6.
Simge Uzun Marion Schelling Kanit Hantanasirisakul Tyler S. Mathis Ron Askeland Genevieve Dion Yury Gogotsi 《Small (Weinheim an der Bergstrasse, Germany)》2021,17(1):2006376
Direct printing of functional inks onto flexible substrates allows for scalable fabrication of wearable electronics. However, existing ink formulations for inkjet printing require toxic solvents and additives, which make device fabrication more complex, limit substrate compatibility, and hinder device performance. Even water-based carbon or metal nanoparticle inks require supplemental surfactants, binders, and cosolvents to produce jettable colloidal suspensions. Here, a general approach is demonstrated for formulating conductive inkjet printable, additive-free aqueous Ti3C2Tx MXene inks for direct printing on various substrates. The rheological properties of the MXene inks are tuned by controlling the Ti3C2Tx flake size and concentration. Ti3C2Tx-based electrical conduits and microsupercapacitors (MSCs) are printed on textile and paper substrates by optimizing the nozzle geometry for high-resolution inkjet printing. The chemical stability and electrical properties of the printed devices are also studied after storing the devices for six months under ambient conditions. Current collector-free, textile-based MSCs show areal capacitance values up to 294 mF cm−2 (2 mV s−1) in poly(vinyl alcohol)/sulfuric acid gel electrolyte, surpassing reported printed MXene-based MSCs and inkjet-printed MSCs using other 2D nanomaterials. This work is an important step toward increasing the functional capacity of conductive inks and simplifying the fabrication of wearable textile-based electronics. 相似文献
7.
Survey of seed oils for use as diesel fuels 总被引:2,自引:0,他引:2
Piyaporn Kalayasiri Narumon Jeyashoke Kanit Krisnangkura 《Journal of the American Oil Chemists' Society》1996,73(4):471-474
Fifty-one out of 364 plant seeds being surveyed had fatty acid contents greater than 15% (dry weight), and their methyl esters
had cetane indices higher than 50. Rambutan seed was an exception, with a lipid content of only 14.7%, but a high cetane index
(67.1); thus, it was included in this report. Twenty seed oil methyl esters had cetane indices greater than 60. Three seed
oils from the Sapindaceae family not only had high cetane indices but also contained long-chain fatty acids of 20 carbon atoms.
Gross heats of combustion of the fatty acid methyl esters were slightly higher than those of neat oil, ranging from 38.2 to
40.8 j/g, whereas the heating values of the oils ranged from 37.4 to 40.5 j/g. Thus, these plant seed oils have great potential
for development as diesel fuel or diesel fuel extender. 相似文献
8.
Xu Xiao Patrick Urbankowski Kanit Hantanasirisakul Yao Yang Stephen Sasaki Long Yang Chi Chen Hao Wang Ling Miao Sarah H. Tolbert Simon J. L. Billinge Hctor D. Abrua Steven J. May Yury Gogotsi 《Advanced functional materials》2019,29(17)
Ultrathin and 2D magnetic materials have attracted a great deal of attention recently due to their potential applications in spintronics. Only a handful of stable ultrathin magnetic materials have been reported, but their high‐yield synthesis remains a challenge. Transition metal (e.g., manganese) nitrides are attractive candidates for spintronics due to their predicted high magnetic transition temperatures. Here, a lattice matching synthesis of ultrathin Mn3N2 is employed. Taking advantage of the lattice match between a KCl salt template and Mn3N2, this method yields the first ultrathin magnetic metal nitride via a solution‐based route. Mn3N2 flakes show intrinsic magnetic behavior even at 300 K, enabling potential room‐temperature applications. This synthesis procedure offers an approach to the discovery of other ultrathin or 2D metal nitrides. 相似文献
9.
Pol Salles David Pinto Kanit Hantanasirisakul Kathleen Maleski Christopher E. Shuck Yury Gogotsi 《Advanced functional materials》2019,29(17)
MXenes, a large family of 2D transition metal carbides and nitrides, have shown potential in energy storage and optoelectronic applications. Here, the optoelectronic and pseudocapacitive properties of titanium carbide (Ti3C2Tx) are combined to create a MXene electrochromic device, with a visible absorption peak shift from 770 to 670 nm and a 12% reversible change in transmittance with a switching rate of <1 s when cycled in an acidic electrolyte under applied potentials of less than 1 V. By probing the electrochromic effect in different electrolytes, it is shown that acidic electrolytes (H3PO4 and H2SO4) lead to larger absorption peak shifts and a higher change of transmittance than the neutral electrolyte (MgSO4) (Δλ is 100 nm vs 35 nm and ΔT770 nm is ≈12% vs ≈3%, respectively), hinting at the surface redox mechanism involved. Further investigation of the mechanism by in situ X‐ray diffraction and Raman spectroscopy reveals that the reversible shift of the absorption peak is attributed to protonation/deprotonation of oxide‐like surface functionalities. As a proof of concept, it is shown that Ti3C2Tx MXene, dip‐coated on a glass substrate, functions as both transparent conductive coating and active material in an electrochromic device, opening avenues for further research into optoelectronic and photonic applications of MXenes. 相似文献
10.
Utilization of rice hull ash as a support material for immobilization of Candida cylindracea lipase 总被引:1,自引:0,他引:1
Jitawan Tantrakulsiri Narumon Jeyashoke Kanit Krisanangkura 《Journal of the American Oil Chemists' Society》1997,74(2):173-175
Rice hull ash was heated in a muffle furnace at 700°C for 2 h and metallic oxides were leached with 10% sulfuric acid. The
acid-activated ash was then examined for immobilization of Candida cylindracea lipase. Immobilization was carried out by direct addition of the enzyme solution to the activated ash suspended in hexane.
The immobilized lipase retained 30% of its hydrolytic activity, but thermal stability was greatly increased. Half-lives of
the immobilized enzyme at 50, 60, and 70°C were 45, 17, and 4 min, respectively. Optimal pH of the immobilized enzyme was
7.2. The apparent Km and Vmax for olive oil were 41 mM and 99.5 μmol/h-mg solid, respectively. 相似文献