scholarly journals Intercalation of urea into kaolinite for preparation of controlled release fertilizer

2014 ◽  
Vol 20 (2) ◽  
pp. 207-213 ◽  
Author(s):  
Fariba Mahdavi ◽  
Rashid Abdul ◽  
Yusop Khanif
Keyword(s):  
Controlled Release ◽  
Hydroxypropyl Methylcellulose ◽  
Colorimetric Method ◽  
Basal Spacing ◽  
Nitrogen Release ◽  
Controlled Release Fertilizer ◽  
Dry Grinding ◽  
Vis Spectroscopy ◽  
Diacetyl Monoxime ◽  
Grinding Technique

In this study urea was intercalated between layers of kaolinite by dry grinding technique to be used for preparing controlled release fertilizer. X-ray powder diffraction (XRPD) patterns confirmed the intercalation of urea into kaolinite by the significant expansion of the basal spacing of kaolinite layers from 0.710 nm to 1.090 nm. Fourier transform infrared spectroscopy (FT-IR) also confirmed the hydrogen bonding between urea and kaolinite. Based on CHNS elemental analysis, 20% (wt.) urea was intercalated between kaolinite layers. The urea-intercalated kaolinite was mixed with hydroxypropyl methylcellulose (HPMC) binder and was granulated to prepare the nitrogen-based controlled release fertilizer. To study the nitrogen release behavior of granules, ultraviolet/visible (UV-Vis) spectroscopy was used through the diacetyl monoxime (DAM) colorimetric method. The result of UV-Vis spectroscopy showed that intercalation of urea into kaolinite decreased the nitrogen release from 25.50 to 13.66 % after 24 hours and from 98.15 to 70.01% after 30 days incubation in water. According to the results, the prepared controlled release fertilizer (CRF) behaved according to the standard for CRFs.

scholarly journals Characterization of Nitrogen Release in Modified Controlled-Release-Fertilizer using Rice Husk Biochar

2020 ◽  
Vol 11 (4) ◽  
pp. 774
Author(s):  
Himawan Tri Bayu Murti Petrus ◽  
Andreas Diga Pratama Putera ◽  
Inasanti Pandan Wangi ◽  
Muhammad Aulia Ramadhian ◽  
Hendrik Setiawan ◽  
...  
Keyword(s):  
Controlled Release ◽  
Rice Husk ◽  
Nitrogen Release ◽  
Controlled Release Fertilizer ◽  
Rice Husk Biochar

Formulation and Evaluation of Nelfinavir Extended Release Trilayer Matrix Tablets by Design of Experiment

2018 ◽  
Vol 11 (5) ◽  
pp. 4259-4268
Author(s):  
Nirmala Rangu ◽  
Gande Suresh
Keyword(s):  
Controlled Release ◽  
Drug Release ◽  
Hydroxypropyl Methylcellulose ◽  
Magnesium Stearate ◽  
Zero Order ◽  
Matrix Tablets ◽  
Drug Dissolution ◽  
Crystalline Cellulose ◽  
Dissolution Profile ◽  
Release Formulation

The present study was aimed to develop once-daily controlled release trilayer matrix tablets of nelfinavir to achieve zero-order drug release for sustained plasma concentration. Nelfinavir trilayer matrix tablets were prepared by direct compression method and consisted of middle active layer with different grades of hydroxypropyl methylcellulose (HPMC), PVP (Polyvinyl Pyrrolidine) K-30 and MCC (Micro Crystalline Cellulose). Barrier layers were prepared with Polyox WSR-303, Xanthan gum, microcrystalline cellulose and magnesium stearate. Based on the evaluation parameters, drug dissolution profile and release drug kinetics DF8 were found to be optimized formulation. The developed drug delivery system provided prolonged drug release rates over a period of 24 h. The release profile of the optimized formulation (DF8) was described by the zero-order and best fitted to Higuchi model. FT-IR studies confirmed that there were no chemical interactions between drug and excipients used in the formulation. These results indicate that the approach used could lead to a successful development of a controlled release formulation of nelfinavir in the management of AIDS.

Study on the Formation of Grind-Hardening of Steel AISI 1066

2007 ◽  
Vol 329 ◽  
pp. 57-62 ◽  
Author(s):  
Ju Dong Liu ◽  
Gui Cheng Wang ◽  
B.L. Wang ◽  
K.M. Chen
Keyword(s):  
Hardened Layer ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Micro Hardness ◽  
Cooling Conditions ◽  
Dry Grinding ◽  
Structures And Properties ◽  
Grind Hardening ◽  
Steel Aisi ◽  
Grinding Technique

Grind-hardening was done on Steel AISI 1066 with a conventional surface grinder and a corundum grinding wheel, and research was conducted to probe into structures and properties of the hardened layer under varied depth of cut and cooling conditions. Results show that the hardened layer do not change noticeably in their martensitic structures and micro-hardness, which is ranged between 810870HV; But when the depth of cut increased or the dry grinding technique is adopted, the concentration of martensites and carbonides becomes lower, while the amount of residual austenites increases, and the completely hardened zone gets thicker. This conclusion serves as an experimental basis for the active control of properties of the grind-hardened layer of Steel AISI 1066.

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