Role of Cooperatives and Participation of their Members in Agricultural Output Marketing: Empirical Evidence from Hetosa District, Ethiopia

Today, in an era where many people feel powerless to change their lives, cooperatives represent a strong, vibrant, and viable economic alternatives. Cooperatives are formed to meet peoples’ mutual needs. They are based on the powerful idea that together, a group of people can achieve goals that none of them could achieve alone. This research paper aims to analyse the role of cooperatives in agricultural output marketing, promoting linkages and to examine factors influencing the level of members’ participation. The cooperatives under investigation have played significant role in output marketing and promoting value adding linkages with different stakeholders. Results of the Tobit model revealed that: farm size, years of membership, amount of improved seed used, output produced and members’ perception on cooperatives price for agricultural outputs were significantly and positively related to the level of participation. Lack of equal opportunity of members in passing decisions, inefficient cooperatives’ employees and incompetent management committee members are found to be the major constraints which hinder cooperatives to properly deliver agricultural output marketing services. To this end, Government, NGOs and other stakeholders need to give emphasis on improving the organizational and institutional capacity of cooperatives

Selective metal ion-capturing by striped nanoparticles

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013.Cataloged from PDF version of thesis.Includes bibliographical references.Nanomaterials have attracted lots of attention due to their tremendous potential in extensive fields, ranging from biology, physics, and chemistry to electronics, and also already proven their superior functionality to conventional materials. The unique properties of nanomaterials comes from their size, morphology, and structure, and frequently a ligand shell structure plays a key role in their distinct behavior and feature since it determines an interaction with environments. We manipulated gold nanoparticles protected by self-assembled monolayer (SAM) of mixed ligand molecules, which have shown noticeable characteristics. Thiolended molecules adsorb onto gold surface, resulting in the formation of SAM. Particularly, two dissimilar ligand molecules undergo a phase-separation on gold nanoparticle surface, and it leads to an ordered structure, alternating striped-like domains. This so-called "striped" structure is induced by a competition between enthalpy and entropy. The longer ligand molecules surrounded by the shorter molecules gain extra conformation entropy at the expense of enthalpy loss, generated by the presence of two different molecules in the same interface. This unique ligand shell structure, i.e. the striped structure, contributes to the superior properties of our gold nanoparticles. Here we report that the striped gold nanoparticles, consisting of a hydrophilic and a hydrophobic molecule, can selectively capture metal ions, of which sensitivity and selectivity are incomparable to homo-ligand coated nanoparticles and disordered structure nanoparticles. The interaction between striped gold nanoparticles and metal ions was intensively demonstrated with various experimental methods, including UV-vis, FT-IR, ITC, zeta potential, and XPS. As a part of application, a solid-state metal ion sensor using striped gold nanoparticles with a different pair of hydrophilic and hydrophobic ligands was exploited. The change of the conductance was measured upon the interaction with a particular metal ion, and it exhibited a matchless selectivity and sensitivity. For example, the conductance of gold nanoparticle film with a specific pair of ligands is changed remarkably with methymercury ions, but that of other kinds films is not, and also it shows extremely low detection limit, which is in the unit of aM (10-¹⁸ M), corresponding to ~600 methylmercury ions in a 1ml of solution. Furthermore, the removal methods of toxic metal ion contaminants from water were manipulated with striped gold nanoparticles, functionalizing with magnetic particles, and also fabricating them as a metal-ion sponge. Additionally, it was observed that these striped nanoparticles display a different ion-capturing behaviour, depending on temperature, which has rarely shown in other ion-chelating materials. This was induced by the entropy effect of the flexible hydrophilic ligands on the striped nanoparticles. Finally, the same ion-capturing behaviour was found in nanoparticles of a different core material (i.e. silver) with Eu³+ions. This proposed the possibility of the use of other core materials when this striped nanoparticle was applied in a real life.by Eun Seon Cho.Ph.D

Domain Reduction Strategy for Non Line of Sight Imaging

This paper presents a novel optimization-based method for non-line-of-sight (NLOS) imaging that aims to reconstruct hidden scenes under various setups. Our method is built upon the observation that photons returning from each point in hidden volumes can be independently computed if the interactions between hidden surfaces are trivially ignored. We model the generalized light propagation function to accurately represent the transients as a linear combination of these functions. Moreover, our proposed method includes a domain reduction procedure to exclude empty areas of the hidden volumes from the set of propagation functions, thereby improving computational efficiency of the optimization. We demonstrate the effectiveness of the method in various NLOS scenarios, including non-planar relay wall, sparse scanning patterns, confocal and non-confocal, and surface geometry reconstruction. Experiments conducted on both synthetic and real-world data clearly support the superiority and the efficiency of the proposed method in general NLOS scenarios

Isolation, structure elucidation and cytotoxic activity of cucurbitacins from Elaeocarpus petiolatus

Four new cucurbitacins (1-4) along with six known compounds, namely, 16α,23α-epoxy-3β,20β-dihydroxy-10αH,23βH-cucurbit-5,24-dien-11-one (5), 16α,23α-epoxy-3β,20β-dihydroxy-10αH,23βH-cucurbit-5,24-dien-11-one 3-O-β-D-glucopyranoside (6), elaeocarpucin F (7), hexanocucurbitacin F (8), β-sitosterol (9), and vomifoliol (10), were isolated from the leaves and bark of Elaeocarpus petiolatus. The structures of the new cucurbitacin compounds were elucidated based on detailed analyses of their 1D and 2D NMR, HRESIMS and MS data. The absolute configuration of compound 1 was established by X-ray diffraction analysis. Compound 1 represents a rare cucurbitacin incorporating an unusual furan-bearing side chain with ketal and epoxide functions, while compound 2 possesses a rare six-fused ring system incorporating a pyranofuranyl ring system. Compound 3 is a new C-5,C-6-epoxide containing cucurbitacin, while compound 4 represents a new acetate derivative of the known cucurbitacin glycoside 6. Compounds 1, 2 and 4 were assessed for their anticancer activity in vitro by using a panel of human cancer cell types, including breast, pancreatic, nasopharyngeal and colon cancer cells. The pure compound 1 showed good cytotoxic effects on breast cancer cell lines (MDA-MB-468, MDA-MB-231, MCF7 and SKBR3) and colorectal cancer cell line (SW48). On the other hand, compound 2 only showed appreciable potency against the MDA-MB-468 and MDA-MB-231 breast cancer cell lines, while compound 4 only showed appreciable potency against the MDA-MB-468 cell line. Further mechanistic investigations are still necessitated in order to determine the potential therapeutic application of these three pure compounds

Thermoelectric properties of graphene incorporated thermoelectric materials

Thermoelectric materials, which can change the waste heat into the usable electricity, are interested in various field of applications such as vehicle, ship, power plane, and so on. To enhance the thermoelectric properties, high electrical conductivity, high Seebeck coefficient, and low thermal conductivity should be conducted, however, the trade-off relation between electronic property and thermal property in terms of carrier concentration could be the bottle-neck on the enhancement of thermoelectric properties of the materials. In this presentation, we discuss with the graphene incorporation in the conventional thermoelectric materials, which could lead to independently control electric and thermal properties

Crystallization Kinetics and Mechanism of CaO-Al2O3-Based Mold Flux for Casting High-Aluminum TRIP Steels

Non-isothermal crystallization of the newly developed lime-alumina-based mold fluxes was investigated using differential scanning calorimetry. The crystallization kinetic parameters were determined by Ozawa equation, the combined Avrami-Ozawa equation, and the differential iso-conversional method of Friedman. It was found that Ozawa method failed to describe the non-isothermal crystallization behavior of the mold fluxes. The Avrami exponent determined by the combined Avrami-Ozawa equation indicates that the crystallization of cuspidine occurs through bulk nucleation and reaction-controlled three-dimensional growth, and then transforms to reaction-controlled two-dimensional growth at the crystallization later stage in lime-alumina-based mold fluxes with higher B2O3 content. For the mold fluxes with lower B2O3 content (10.8 mass pct), the crystallization of cuspidine is bulk nucleation and reaction-controlled two-dimensional growth at the crystallization primary stage followed by a diffusion-controlled two-dimensional growth process. The crystallization of CaF2 in mold flux originates from bulk nucleation and diffusion-controlled three-dimensional growth, which then transforms to two-dimensional growth. FE-SEM observations support these kinetic analysis results. The effective activation energy for cuspidine crystallization in the mold flux with higher B2O3 and Na2O contents increases as the crystallization progresses, and then decreases at the relative degree of crystallinity greater than 60 pct. The transition point of this trend approximately corresponds to the relative degree of crystallinity at which the crystallization mode of cuspidine transforms. For the mold fluxes with lower B2O3 and Na2O contents, the effective activation energy for cuspidine formation varies monotonically with the increase in the relative degree of crystallinity.open11149sciescopu

Evaluation of Matusita Equation and Its Modified Expression for Determining Activation Energy Associated with Melt Crystallization

Both the Matusita equation and the modified Matusita equation for estimating the activation energy associated with non-isothermal crystallization were critically evaluated. The derivation for melts crystallization on cooling indicates that, unlike for the crystallization that occurs on heating, the term 1 - exp (-Delta G/RT) in the basic rate equation of crystal growth and the term depending on the initial temperature of the cooling process cannot be neglected. It is demonstrated that both the Matusita equation and its modified expression are only valid to estimate the activation energy associated with the crystallization that occurs on heating, but are inapplicable for the melt crystallization that occurs on cooling. It is suggested that the isoconversional methods of Friedman and Vyazovkin should be alternative to determine effective activation energy for melt crystallization that occurs on cooling.open1133sciescopu

Phase Current Measurement Method of Dual Inverter-Motor Drive System Using a Single DC Link Current Sensor

In recent years, electric propulsion systems have become widely, used and these systems have strict limits in volume and weight. Therefore, it is necessary to reduce the weight of the inverter-motor drive system. In a typical n inverter-motor drive system, at least 2n phase current sensors are required. In order to reduce the number of phase current sensors, this paper proposes a method for measuring phase current using n DC link current sensors in a 2n inverter-motor drive system. Two phase currents per inverter-motor system are measured during one period of the switching frequency using the pulse width modulation (PWM) shift method. However, since the measured phase current contains an error component in the average current, the error component was compensated for in order to obtain a current similar to the actual phase current by using the slope and dwell time of the phase current. The effectiveness of the proposed method is verified through experiments

Visible-ultraviolet spectroscopic ellipsometry of lead zirconate titanate thin films

We measured pseudodielectric functions in the visible-ultraviolet spectral range of Pb(ZrxTi1−x)O3 (x=0.2, 0.56, 0.82) (PZT)grown on platinized silicon substrate using the sol-gel method and also on (0001) sapphire using radio frequency sputtering method. Using a parametric optical constant model, we estimated the dielectric functions of the PZTthin films. Taking the second derivative of the fitted layer dielectric functions and using the standard critical point model, we determined the parameters of the critical points. In the second derivative spectra, the lowest bandgap energy peak near 4eV is fitted as a double peak for annealedPZTs associated with the perovskite phase. As-grown PZTs have mainly pyrochlore phase and the lowest bandgap is fitted as a single peak. We compared the bandgap energies with literature values