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Home > Synthesis and Characterization of Nanocomposites As Slow Release Environment Friendly Fertilizers

Synthesis and Characterization of Nanocomposites As Slow Release Environment Friendly Fertilizers

Thesis Info

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Author

Lateef, Ambreen

Program

PhD

Institute

University of the Punjab

City

Lahore

Province

Punjab

Country

Pakistan

Thesis Completing Year

2018

Thesis Completion Status

Completed

Subject

Environmental Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/10122/1/Ambreen%20Lateef_Env%20Sci_2018_UoPunjab_PRR.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725064160

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Agriculture is the back bone of economic development of any agricultural country and it has been transformed into a vast industry fulfilling the primary needs of the masses. Sustainability in agriculture sector is a serious concern specifically in the perspective of environmental conservation as well as maintaining rather improving the crop productivity. This research work was designed to prepare environmentally friendly slow release nano-fertilizer as a substitute for conventional chemical fertilizers that could protect the environment from deleterious effects of conventional chemical fertilizers without compromising agricultural productivity. Two types of nano-composites, based on zeolite (ZNC) and biochar (BNC), with a particle size of 6.05 and 55.6nm, were synthesized by adopting two-step approach and compared with conventional chemical fertilizers. In the first step support materials i.e. nano zeolite (NZ) and biochar of corncob (CB) were synthesized and in the second step support materials were impregnated/ doped with micro and macro nutrients. Physiochemical properties of both the support materials (NZ & CB) and their nanocomposites (ZNC & BNC) were determined using standard methods. While the structure, morphological features, chemical composition, size and thermal stability were determined by fourier transmission infrared spectroscopy (FT-IR), powder x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), atomic force microscopy (AFM) and thermogravimetric analysis (TGA). Slow release properties of ZNC & BNC carried out in water as well as in soil for 7 and 14 days, respectively, that confirmed the gradual release and long time availability of all the doped nutrients (N, P, K, Ca, Mg, Fe, Zn). Concurrently, the synthesized nano-composites showed excellent water absorbance, salt index and water retention capacities that is good to enhance the soil condition without imparting negative impacts to the crops. The nano-composites’ capability to enhance crop production in comparison to conventional fertilizers was accessed primarily by performing greenhouse experiments on wheat – a major cash crop of Pakistan that is widely grown and serving the purpose of staple food in Pakistan. The completely randomized design with five treatments (control, urea, NPK, ZNC and BNC) was laid ii down, to study the germination parameters; time for 50% germination (T50), mean germination time (days), final germination percentage (%) and germination index. The results indicated early sprouting and germination in ZNC followed by BNC than conventional fertilizers (i.e. urea and NPK). After positive germination results of greenhouse experiment, the field trials were carried on using the same approach i.e. RCBD with three replicates of each treatment to examine the effect of nano-composites on growth and yield parameters for two consecutive years (2014 - 2016). The results were statistically analyzed using one- way ANOVA (LSD at 0.5%) and means were separated by standard errors. The results of field trials demonstrated that nano-composites (ZNC & BNC) positively influenced growth and yield of wheat crop as compared to conventional fertilizers (urea and NPK) and control. In the first year, the highest grain yield was found for ZNC followed by BNC, NPK, urea and lowest for control treatment. While in the second year the scenario was slightly changed and the highest yield was observed in BNC followed by ZNC; the rest of the pattern is same as previous i.e. NPK > urea >control. The proximate, antioxidant and nutritional analysis of wheat grain were performed to determine the comparative effect of nano-composites (ZNC & BNC) with conventional fertilizers. The results demonstrated that nano-composites had marked influence on nutritional quality, antioxidant activity and proximate analysis of wheat grain as compared to urea and NPK. Similarly, comparison of pre and post-cropharvest analysis of soil confirmed that use of nano-composites improve the quality of the soil. Finally, the viability of these nano-composites was quantified through economic analysis for the feasibility of this new approach in field application. The results showed that nano-composites significantly enhanced the gross benefit as compared to conventional fertilizers. Hence, it can be safely concluded that use of these nanocomposites will not only protect the environment but also enhance the yield, nutritional quality of crops and income of farmers by reducing the fertilizer input cost thereby ensuring sustainable agriculture development.
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اُس نے بھی کیا چاہے وہ اقرار نہیں تھا

اُس نے تو کیا چاہے وہ اقرار نہیں تھا
ایسا بھی نہیںمجھ سے اُسے پیار نہیں تھا
اب شکل مری مجھ سے بھی تو ملتی نہیں ہے
ایسا تو کبھی مَیں اے مرے یار نہیں تھا

محمود تيمور كمصلح اجتماعي

Born in 1894 in "Darb Sadah" of Cairo: Mehmood Taimur has attained a distinguished place in the world of literature. Besides writing literature, he has also written many essays/articles. He has highlighted social problems in his social essays and has become a social reformer. He has pinpointed the following social issues in these essays: (1) He has exposed the social ills like class distinction: sexual deprivation destitute and ignorance. (2) He has also acquainted the people about the causes of polygamy and divorce in the light of Shariat and rejects the contention with the solid argument that woman is a weak creature subjected to all kind of wrong treatment. Every person has a right to lead a peaceful life in this world and no one has the right to deprive him of this privilege except owing to some Islamic law. Most of the people were unaware of the rights of woman granted by Islam or they were not accepting them but Mehmood Taimur has presented all those rights in a beautiful way before society that is why on reading his social essays man reaches the conclusion that he was a social reformer.

Higher Order Sliding Mode Control Based Sr Motor Control System Design

This thesis presents a novel scheme for speed regulation/tracking of Switched Reluctance (SR) motors based on Higher-Order Sliding-Mode technique. In particular, a Second-Order Sliding-Mode Controller (SOSMC) based on Super Twisting algorithm is developed. Owing to the peculiar structural properties of SRM, torque produced by each motor phase is a function of phase current as well as rotor position. More importantly, unlike many other motors the polarity of the phase torque in SR motors is solely determined by the rotor position and is independent of the polarity of the applied voltage or phase current. SR motor needs an electronic commutation scheme for its operation. So design of commutation scheme plays an important role in motor efficiency and performance. This commutation scheme is embedded in its power supply as switching timers. The existing commutation schemes cause high power loss and based on those commutation schemes, the existing controller techniques for SR motor show low robustness especially when motor’s parameters change. Therefore a new commutation scheme is developed which optimizes power consumption in motor phases. On the bases of this commutation scheme, a new controller technique is used to design controller for SR motor which is highly efficient, simple to design and easy to implement and also provides sufficient robustness against parameter variations and unknown disturbances. The proposed controllers take advantage of this property and incorporate a commutation scheme which, at any time instant, selects to energize only those motor phases for the computation of control law, which can contribute torque of the desired polarity at that instant. This feature helps in achieving the desired speed regulation/tracking objective in a power efficient manner as control efforts are applied through selective phases and phases producing the torque of opposite polarity are kept switched off. This approach also minimizes the power loss in the motor windings reducing the heat generation within the motor. The common techniques for designing the SR Motor controls are fuzzy logic control, Artificial Neural Network (ANN) and feedback linearization. Fuzzy logic control provides sufficient robustness against parameter variations but at a high computational cost. Artificial Neural Network (ANN) shows good dynamic response against unknown disturbances but problem in using this technique is requirement of a large training data set. In the feedback linearization technique, nonlinear control problem is transformed into linear control problem and then any one of the well established and mature linear controller techniques are applied on the resulting system. Feedback linearization cannot be applied to all types of nonlinear systems; and in case of parameters uncertainties, the robustness cannot be guaranteed. All the deficiencies in discussed techniques can be overcome by introducing sliding mode control which is simple, easy to implement and provides robustness. The inherent problem of chattering in classical FOSMC can further be improved by using higher order sliding mode control (HOSMC). In order to highlight the advantages of Higher-Order Sliding-Mode controller, a classical First-Order Sliding-Mode controller (FOSMC) is also developed and applied to the same system. The comparison of the two schemes shows much reduced chattering and low power consumption in case of SOSMC. This feature is especially very important for SR motor control, due to reduced chattering; wear and tear problem of actuators is reduced. The responses of synthesized controllers are also investigated against changes in moment of inertia which could be due to engagement of load; stator phase resistance which could vary due to temperature variations in winding during operation and coefficient of viscous friction as a model uncertainty. The performance of the proposed SOSMC controller for speed regulation is also compared with that of another sliding mode speed controller published in the literature and also with dynamic sliding mode controller. The same technique is also applied on position control problem and, FOSMC and SOSMC are developed for position regulation problem; making it possible candidate for servo drive application.