1,705 research outputs found
Competing Screening Rules
Various studies show that agricultural cooperatives behave differently than their investor-owned counterparts. One explanation may be that the internal decision making process differs in these two governance structures. A model is developed to explore how endogenous screening rules affect efficient organizational choices and industrial structures. It is shown that screening level choice may outweigh architecture choice and that screening rules are strategic substitutes. Conditions are derived under which cooperatives are efficient organizational forms. It is also shown that competition may increase the attractiveness of investor-owned firms and circumstances are determined in which cooperatives and investor owned firms coexist in equilibrium.architecture, screening, cooperatives, duopoly, Agribusiness, Q13,
Organization and Strategy of Farmer Specialized Cooperatives in China
A description and analysis of China's Farmer Specialized Cooperatives is presented. Data is presented regarding the historical development of farmer cooperatives in China, the membership composition of a sample of 66 farmer cooperatives in the Zhejiang province, and the various attributes (governance, quality control system, and strategy) of a watermelon cooperative in this province. Many cooperatives are being transformed in organizations with a market orientation. These cooperatives exhibit substantial heterogeneity, in terms of farmers being member and skewness in the distribution of control rights. Human asset specificity in terms of establishing and maintaining relations and access to markets seems to be more important than physical asset specificity in accounting for governance structure choice in the current institutional setting.Farmer Cooperative, China, Governance Structure, Business Strategy, Agribusiness, Q13,
Effects of metal particles on cold spray deposition onto Ti-6Al-4V alloy via Abaqus/Explicit
Titanium alloy is the main structural material of the aerospace system component. About 75 % of titanium
and titanium alloys in the world are used in the aerospace industry. Hence, it is of great significance to study the surface
deposition characteristics by cold spraying technology, taking Ti-6Al-4V alloy as an example, smoothed particle
hydrodynamics (SPH) method in Abaqus/Explicit was used to spray aluminum, Ti-6Al-4V, copper, tungsten alloy (W
alloy) and titanium particles onto Ti-6Al-4V substrate. The simulation results show that the deposition effect is good
over 600 m/s, and higher energy is obtained for Ti-6Al-4V particles with the same properties as the matrix. For
aluminum, Ti-6Al-4V, copper, W alloy, and titanium particles with different properties, under the same initial speed
condition, the greater the density of the material, the deeper the foundation pit. W Alloy has the largest initial kinetic
energy, the deepest foundation pit, and better surface bonding performance. The aluminum particle has the smallest
initial kinetic energy, the shallowest foundation pit. However, the deposition effect of multiple aluminum particles has
not improved. The collision process’s kinetic energy is transformed into internal energy, frictional dissipation, and
viscous dissipation. Besides, the internal energy is mainly plastic dissipation and strain energy. Therefore, it is
recommended to use Ti-6Al-4V, copper, nickel, W alloy, and titanium particles for different occasions, such as Ti-6Al4V substrate surface restorative and protective coatings. Pure aluminum particles are not recommended
Experimental method for biaxial tensile strength of fabrics and preliminary investigations
This paper presents a novel experimental approach to determine the biaxial strength of fabrics. A double-layer cruciform specimen was proposed based on the improvement of previous test specimen. The design and manufacture process of the novel specimen was described in detail. Uniaxial and biaxial tests of a specific material were performed subsequently. Based on numerical simulation, the biaxial strength of the fabrics was preliminary investigated. And the correlation between uniaxial and biaxial strength of the material was discussed. The proposed experiments could characterize the biaxial strength of fabrics, and the biaxial strength of the fabrics at 1:1 tension is higher than the weft strength and little lower than the warp strength
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Alcohol Consumption, Mediating Biomarkers, and Risk of Type 2 Diabetes Among Middle-Aged Women
OBJECTIVE—The purpose of this study was to investigate whether adiponectin concentrations and biomarkers of inflammation, endothelial dysfunction, and insulin resistance mediate the association between alcohol consumption and diabetes. RESEARCH DESIGN AND METHODS—In a nested case-control study of 705 women with incident diabetes and 787 matched control subjects, we examined the adjusted relationship between baseline alcohol consumption and risk of diabetes before and after adjustment for markers of inflammation/endothelial dysfunction (C-reactive protein, vascular cell adhesion molecule-1, intercellular adhesion molecule-1, E-selectin, tumor necrosis factor-α receptor 2, and interleukin-6), fasting insulin, and adiponectin concentrations. RESULTS—Alcohol consumption was associated with a decreased risk of diabetes (odds ratio per 12.5 g/day increment in alcohol use 0.58; 95% CI 0.49–0.69; P 2% of the observed relationship. Without adjustment for BMI, these biomarkers individually explained slightly more of the association, but <10% in all cases. Adiponectin accounted for 25% in a fully adjusted model and for 29% without adjustment for BMI. CONCLUSIONS—In this population of women, alcohol consumption was inversely associated with risk of type 2 diabetes. Adiponectin appeared to be a mediator of this association, but circulating biomarkers of inflammation, endothelial dysfunction, and fasting insulin did not explain this association. These results suggest that further research is needed into the potentially mediating roles of other biomarkers affected by alcohol consumption
Study of a cold spray nozzle throat on acceleration characteristics via CFD
Cold spray technology can obtain coatings in a solid state, suitable for deposition protection, repair, and
additive manufacturing. In order to further expand the application areas of cold spraying nozzles, especially the inner
surface of the components or areas where a Straight-line conical nozzle cannot be applied, because the study of the
throat of the nozzle with the angle will directly reduce the total length of the nozzle (the horizontal direction), hence,
the spray with the angle will show its advantage. This study discusses the influence of the throat structure of the conical
cold spray nozzle on the acceleration characteristics, including the throat’s size, length, and angle. The results show the
following. Firstly, under the premise of keeping the shrinkage ratio and divergence ratio unchanged at normal
temperature, the throat diameter is between 2–6 mm in size, and the maximum growth rate exceeds 20 m/s. When the
throat exceeds 6mm, the growth rate of the outlet slows down, and the growth rate is only 8 m/s. Secondly, the length
of the throat has little effect on the acceleration characteristics, the total range fluctuated from 533 to 550 m/s, and
11 mm length of the throat is the closest to 0mm. Additionally, the 90° throat angle has the least effect on the
acceleration characteristics. Finally, the particle trajectory is affected by inlet pressure, injection pressure, particle size,
and other factors
Ball on a beam: stabilization under saturated input control with large basin of attraction
This article is devoted to the stabilization of two underactuated planar
systems, the well-known straight beam-and-ball system and an original circular
beam-and-ball system. The feedback control for each system is designed, using
the Jordan form of its model, linearized near the unstable equilibrium. The
limits on the voltage, fed to the motor, are taken into account explicitly. The
straight beam-and-ball system has one unstable mode in the motion near the
equilibrium point. The proposed control law ensures that the basin of
attraction coincides with the controllability domain. The circular
beam-and-ball system has two unstable modes near the equilibrium point.
Therefore, this device, never considered in the past, is much more difficult to
control than the straight beam-and-ball system. The main contribution is to
propose a simple new control law, which ensures by adjusting its gain
parameters that the basin of attraction arbitrarily can approach the
controllability domain for the linear case. For both nonlinear systems,
simulation results are presented to illustrate the efficiency of the designed
nonlinear control laws and to determine the basin of attraction
Criticality of the Mean-Field Spin-Boson Model: Boson State Truncation and Its Scaling Analysis
The spin-boson model has nontrivial quantum phase transitions at zero
temperature induced by the spin-boson coupling. The bosonic numerical
renormalization group (BNRG) study of the critical exponents and
of this model is hampered by the effects of boson Hilbert space
truncation. Here we analyze the mean-field spin boson model to figure out the
scaling behavior of magnetization under the cutoff of boson states . We
find that the truncation is a strong relevant operator with respect to the
Gaussian fixed point in and incurs the deviation of the exponents
from the classical values. The magnetization at zero bias near the critical
point is described by a generalized homogeneous function (GHF) of two variables
and . The universal function has a
double-power form and the powers are obtained analytically as well as
numerically. Similarly, is found to be a GHF of
and . In the regime , the truncation produces no effect.
Implications of these findings to the BNRG study are discussed.Comment: 9 pages, 7 figure
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