109 research outputs found
Study on the project supervision system based on the principal-agent theory
Purpose: In order to solve problems in the current project management system, the paper presents the asymmetric information games existing in construction projects through information economics viewpoints.
Design/methodology/approach: The owner has private information about the project profitability and he exerts an unobservable level of effort in order to increase the feasibility of successfully completing the project in terms of meeting product specifications. The paper analyzes the principal-agent relationship between the owner and supervisor with âprincipal-agent theoryâ of the game theory. In addition, the paper validates the model through two project cases.
Findings: We can conclude that the incentive contract plays an important role in reducing the moral hazard. The main contribution of this studyis to examine the influence of both pre-contractual private information and the sensitivities between the interrelated performance measures on the design of an optimal incentive contract.
Social implications: At last, some advices are put forward to advance the project management system in China, and some external mechanism can effectively inhibit the"moral hazard" and "adverse selection" to occur.
Originality/value: A model of principal-agent relationship between the owner and supervisor is formulated. This model takes consideration of the moral hazard, which isdifferent from most existing researches in this field.Peer Reviewe
Control of Wind-Induced Vibration of Transmission Tower-Line System by Using a Spring Pendulum
The high-voltage power transmission tower-line system, which is a high flexible structure, is very susceptible to the wind-induced vibrations. This paper proposes the utilization of the internal resonance feature of the spring pendulum to reduce the wind-induced vibration of a transmission tower. The kinetic expression of the spring pendulum system is obtained through Lagrangian equation. The condition of the internal resonance is verified to be λâ=â2, in which λ is the ratio of the spring mode frequency over the pendulum mode frequency. A 55âm tower in the Liaoning province is established in SAP2000 to numerically verify the effectiveness of the proposed device. The spring pendulum is modeled using Link element. The wind speed history is generated based on Kaimal spectrum using harmonic superposition method. Results show that, (1) compared with the suspended mass pendulum, the spring pendulum absorbs more energy and reduces the oscillation more effectively and (2) the vibration control performance of the proposed spring pendulum improves as the external wind load increases
Evaluation of different hydrocolloids to improve dough rheological properties and bread quality of potato-wheat flour
peer reviewedThe aim of study was to investigate the effect of hydroxylpropylmethylcellulose (HPMC), arabic gum (AG), konjac glucomannan (KG) and apple pectin (AP) at 2% (w/w, potato-wheat flour basis) on the potato-wheat dough (the mass ratio was 1:1) rheological, fermentation properties and its bread quality. The tan ÎŽ of potato-wheat dough was significantly increased by adding HPMC compared to those of without adding hydrocolloids (from 0.337 to 0.425), which was close to wheat dough (0.531). Moreover, the dough height during fermentation process was significantly improved by adding hydrocolloids, with the order of HPMC (23.1mm) > AP (19.3mm) > AG (18.6mm) > KG (13.6mm). In addition, the potato-wheat protein bands of potato-wheat dough turned pale by adding hydrocolloids, suggesting higher molecular weight aggregation formed between proteins-hydrocolloids or proteins-proteins after fermentation process. Furthermore, HPMC significantly increased specific volume (from 1.45 to 2.22 ml/g), and hydrocolloids restrained the starch retrogradation of potato-wheat breads.Research Project: Research and Demonstration of Key Technology System of Potato Staple Food (201503001-2
OleD Loki as a Catalyst for Tertiary Amine and Hydroxamate Glycosylation
We describe the ability of an engineered glycosyltransferase (OleD Loki) to catalyze the Nâglycosylation of tertiaryâamineâcontaining drugs and trichostatin hydroxamate glycosyl ester formation. As such, this study highlights the first bacterial model catalyst for tertiaryâamine Nâglycosylation and further expands the substrate scope and synthetic potential of engineered OleDs. In addition, this work could open the door to the discovery of similar capabilities among other permissive bacterial glycosyltransferases
Highly Aligned Ni-Decorated GOâCNT Nanostructures in Epoxy with Enhanced Thermal and Electrical Properties
In this study, graphene oxideâcarbon nanotubes nanostructures decorated with nickel nanoparticles (NiGNT) were prepared through the molecular-level-mixing method, followed by a reduction process, and then applied as reinforcements to enhance the epoxy resin matrix. The ferromagnetism of the Ni nanoparticles allowed NiGNT nanostructures to be vertically aligned within the composite with the assistance of a magnetic field. Due to the alignment distribution of the NiGNT, the composites demonstrated enhanced anisotropic thermal and electrical conduction performances, compared with pure epoxy and randomly distributed composites. The aligned distribution of NiGNTâepoxy composites displayed 2.7 times higher thermal conductivity and around 104 times better electrical conduction performance, compared with pure epoxy. The thermal expansion of NiGNTâepoxy composite was also restricted in the aligned direction of NiGNT nanostructures. Thus, NiGNTâepoxy composites show great potential as future aerospace, aviation, and automobile materials
Slow water transport in MgSO<sub>4</sub> aerosol droplets at gel-forming relative humidities
The effect of gel formation on water transport in MgSO4 aerosol droplets is investigated by deriving apparent diffusion coefficients of water.</p
Evaluation of different hydrocolloids to improve dough rheological properties and bread quality of potato-wheat flour
The aim of study was to investigate the effect of hydroxylpropylmethylcellulose (HPMC), arabic gum (AG), konjac glucomannan (KG) and apple pectin (AP) at 2% (w/w, potatoâwheat flour basis) on the potatoâwheat dough (the mass ratio was 1:1) rheological, fermentation and bread making properties. The tan d of potatoâwheat dough was significantly increased upon addition of adding HPMC which was close to wheat dough (0.531). Moreover, dough height during fermentation process was significantly improved on addition of hydrocolloids, with the order of HPMC (23.1 mm)[AP (19.3 mm)[AG (18.6 mm)[ KG (13.6 mm). Protein bands of potatoâwheat dough were pale in the presence of hydrocolloids, suggesting the formation of higher molecular weight aggregates formed between proteinsâhydrocolloids or proteinsâproteins after fermentation process. Furthermore, HPMC significantly increased specific volume (from 1.45 to 2.22 ml/g), and hydrocolloids restricted the retrogradation of starch in potatoâwheat breads.Centro de InvestigaciĂłn y Desarrollo en CriotecnologĂa de AlimentosFacultad de Ciencias Exacta
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