Azizah Shaaban

Boric acid modified starch polyvinyl alcohol matrix for slow release fertilizer

Abstract The slow release urea fertilizer was prepared by the boric acid crosslinked starch/polyvinyl alcohol (SPB) matrix as biodegradable carrier material. Using a two level factorial design of experiment, a comprehensive understanding of the concentration of boric acid, reaction time and heating temperature in the preparation of SPB matrix was obtained. The swelling ratio, release profile of urea in water, and crushing strength were selected as the response. The interaction between the variables and response was analyzed using the ANOVA model. The system was confirmed using the constant determination, R2 with values above 0.99. The high concentration of boric acid with a prolonged reaction time at high temperature gave relative good results of swelling ratio, dissolution rate of urea and crushing strength. In the 28-day soil incubation experiment, the retention of exchangeable ammonium ion (NH4+)

Microwave absorbing material using rubber wood sawdust

{\rm{(NH}}_4^ + )

The effect of the carbon to the S 11 measurement on the pyramidal microwave absorbers

was significant higher in SPB urea as compared to pure urea. There was a potential for SPB matrix to improve nitrogen efficiency by increasing the accumulation of exchangeable NH4+

Application of Response Surface Methodology for Optimization of Urea Grafted Multiwalled Carbon Nanotubes in Enhancing Nitrogen Use Efficiency and Nitrogen Uptake by Paddy Plants

{\rm{NH}}_4^ +

Rheological Properties of Urea-CaLS Mixture for Urea Fertilizer Granulation

and decreasing the dissolution rate of urea in the flooded condition.

Effect of Functionalised and Non-Functionalised Carbon Nanotubes-Urea Fertilizer on the Growth of Paddy

A flat microwave absorber working at frequency 1.8GHz was developed by impregnation of activated carbon and polyurethane. The activated carbon is prepared from the conversion of rubber wood sawdust through chemical activation process using ZnCl2 solution as the precursor agent. The process involves leaching, heating and washing. The impregnation ratio between ZnCl2 and rubber wood sawdust were at 1∶1, 1.5∶1 and 2∶1. All samples are heated at temperature of 500°C for 60 minutes. It was found that the chemical activation at impregnation ratio of 2∶1 produced high purity activated carbons with 79 percent carbon content. Based on the BET analysis, the surface area of the powder for impregnation ratio 1.5∶1 reported highest value of 1301 m2/g, this formulation is selected for making microwave absorber and it was reported that the reflection loss is recorded 10dB at 1.8 GHz.

Optimization of Fluidised Bed Granulation Process Parameters for Urea Granule Manufacturing Using the Response Surface Method

The purpose of this work is to determine the absorption effect by using carbon as absorbing material. It will be used in anechoic chamber in order to avoid reflections that occur on the wall of the chamber. From polystyrene, the absorbers are cut into pyramidal shaped. The pyramidal shaped is chosen because it could meet the specified industrial standards which can work well at wide range of microwave frequency. To verify the performance of the absorber, a measurement is conducted to determine the absorption rate in frequency range 1 to 10 GHz. The absorber also compared to commercial absorber. The results shows carbon is a good material to absorb the microwave energy. The absorber that has been developed is a low cost with reliable performance.

Slow Release of Urea Encapsulated by Starch PVA Matrix

Efficient use of urea fertilizer (UF) as important nitrogen (N) source in the world’s rice production has been a concern. Carbon-based materials developed to improve UF performance still represent a great challenge to be formulated for plant nutrition. Advanced N nanocarrier is developed based on functionalized multiwall carbon nanotubes (f-MWCNTs) grafted with UF to produce urea-multiwall carbon nanotubes (UF-MWCNTs) for enhancing the nitrogen uptake (NU) and use efficiency (NUE). The grafted N can be absorbed and utilized by rice efficiently to overcome the N loss from soil-plant systems. The individual and interaction effect between the specified factors of f-MWCNTs amount (0.10–0.60 wt%) and functionalization reflux time (12–24 hrs) with the corresponding responses (NUE, NU) were structured via the Response Surface Methodology (RSM) based on five-level CCD. The UF-MWCNTs with optimized 0.5 wt% f-MWCNTs treated at 21 hrs reflux time achieve tremendous NUE up to 96% and NU at 1180 mg/pot. Significant model terms ( value < 0.05) for NUE and NU responses were confirmed by the ANOVA. Homogeneous dispersion of UF-MWCNTs was observed via FESEM and TEM. The chemical changes were monitored by FT-IR and Raman spectroscopy. Hence, this UF-MWCNTs’ approach provides a promising strategy in enhancing plant nutrition for rice.

Potential of Epoxidized Natural Rubber (ENR) as Hydrophobicity Contributor in Chitosan-Urea Fertilizer

The rheological properties of feedstock for granulation process are important in controlling the parameters throughout the process. This study identifies the type of fluid that mixtures of Urea and Calcium Lignosulfonates (CaLS) possessed through the viscosity profiles using a parallel plate rheometer. The viscosity behavior of mixtures with varied weight percentages (wt %) of CaLS in urea solution were analysed. Results identified that the mixtures show shear thickening behavior of non-Newtonian fluid. It is also observed that the increases of CaLS content increase the viscosity of the mixtures. Moreover, the mixture with 50 % CaLS addition is found not suitable for further investigation as its viscosity is too high (3.450-6.773 Pa.s at zero shear rate) compared to molten urea (0.002 Pa.s).

Assessing the significance of rate and time pulse spraying in top spray granulation of urea fertilizer using Taguchi Method

The roles of multi-walled carbon nanotubes (MWNTs) and functionalised multiwalled carbon nanotubes (fMWNTs) in enhancing the efficacy of urea fertilizer (UF) as plant nutrition for local MR219 paddy variety was investigated. The MWNTs and fMWNTs were grafted onto UF to produce UF-MWNTs fertilizer with three different conditions, coded as FMU1 (0.6 wt. % fMWNTs), FMU2 (0.1 wt. % fMWNTs) and MU (0.6 wt. % MWNTs. The batches of MR219 paddy were systematically grown in accordance to the general practice performed by the Malaysian Agricultural Research and Development Institute (MARDI). The procedure was conducted using a pot under exposure to natural light at three different fertilization times; after a certain number of days of sowing (DAS) at 14, 35 and 55 days. Interestingly, it was found that the crop growth of plants treated with FMU1 and FMU2 significantly increased by 22.6% and 38.5% compared to plants with MU addition. Also, paddy treated with FMU1 produced 21.4% higher number of panicles and 35% more grain yield than MU while paddy treated with FMU2 gave 28.6% more number of panicles and 36% higher grain yield than MU, which implies the advantage of fMWNTs over MWNTs to be combined with UF as plant nutrition. The chemical composition and morphology of UF-MWNTs fertilizers which is further characterised by FTiR and FESEM confirmed the successful and homogeneous grafting of UF onto the fMWNTs.