• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.5
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• pp.75-81
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• 2011

Recently prestressed concrete bridges are generally used instead of reinforced concrete. PSC is more durable than RC because it can reduce crack problems, reinforcement corrosion, leakage and carbonation etc. And also PSC is more effective because there is no crack in tension area, and the entire concrete section is considered in section analysis. And it can reduce section size because vertical component by prestressing force can reduce the shear force. However, using high strength concrete can increase the self weight of bridge because of it's higher density. So the hollowed PPC girder with light weight aggregate can be a alternative. In this study the hollowed PPC girder with light weight aggregate is designed and the performance of hollowed PPC girder is evaluated by experimental tests as well as numerical analysis. As a result, The hollowed PPC girder of light aggregate behaved fully elastically under service load of 110kN, and the plastic behavior was showed after elastic behavior through experimental test, and it can be also estimated by numerical analysis.

• Korean Chemical Engineering Research
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• v.58 no.1
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• pp.36-43
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• 2020

A biliant stent was fabricated using a magnesium alloy wire, a biodegradable metal. In order to control the fast decomposition and corrosion of magnesium alloys in vivo, magnesium alloy wires were coated with biodegradable polymers such as polycaprolactone (PCL), poly(propylene carbonate) (PPC), poly (L-lactic acid) (PLLA), and poly (D, L-lactide-co-glycolide) (PLGA). In the case of PPC, which is a surface erosion polymer, there is no crack or peeling compared to other polymers (PCL, PLLA, and PLGA) that exhibit bulk erosion behavior. Also, the effect of biodegradable polymer coating on the axial force, which is the mechanical property of magnesium alloy stents, was investigated. Stents coated with most biodegradable polymers (PCL, PLLA, PLGA) increased axial forces compared to the uncoated stent, reducing the flexibility of the stent. However, the stent coated with PPC showed the axial force similar to uncoated stent, which did not reduce the flexibility. From the above results, PPC is considered to be the most efficient biodegradable polymer.

• Journal of the Korea institute for structural maintenance and inspection
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• v.2 no.3
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• pp.168-175
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• 1998

This study investigated the structural performance of the precast prestressed cylinder pipe having cracked under construction. The finite element formulation of PPC pipe incorporates Asoild elements using SAP90 program and the radial prestress force was transformed into the eqivalent external pressure. The analytical results were compared with the experimental results of full scale tests on PPC pipes subjected to static load. It is shown that the proposed modelling gives a realistic represention of the actual behavior. The analytical procedure is used to calculate the stresses in the PPC pipes and to check the crack opening under various situations such as bedding angle, earth pressure, and earth cover. Finally, the proposed modelling and analytical procedure should be especially usefull for the safety assessment of the PPC pipes under general loading conditions.

• Smart Structures and Systems
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• v.13 no.6
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• pp.943-957
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• 2014

When subjected to fatigue loading, the main failure mode of partially prestressed concrete (PPC) structure is the fatigue fracture of tensile reinforcement. Therefore, monitoring and evaluation of the steel stresses/strains in the structure are essential issues for structural design and healthy assessment. The current study experimentally investigates the possibility of using fiber Bragg grating (FBG) sensors to measure the steel strains in PPC beams in the process of fatigue loading. Six full-scale post-tensioned PPC beams were exposed to fatigue loading. Within the beams, the FBG and resistance strain gauge (RSG) sensors were independently bonded onto the surface of tensile reinforcements. A good agreement was found between the recorded results from the two different sensors. Moreover, FBG sensors show relatively good resistance to fatigue loading compared with RSG sensors, indicating that FBG sensors possess the capability for long-term health monitoring of the tensile reinforcement in PPC structures. Apart from the above findings, it can also be found that during the fatigue loading, there is stress redistribution between prestressed and non-prestressed reinforcements, and the residual strain emerges in the non-prestressed reinforcement. This phenomenon can bring about an increase of the steel stress in the non-prestressed reinforcement.

• Journal of Distribution Science
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• v.13 no.7
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• pp.25-31
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• 2015

Purpose - This study aims to measure the influence of the positive psychological capital (PPC) of business workers by using innovative work behavior (IWB) and the influence of Leader-member exchange (LMX) and Member-member exchange (MMX) in this relation and investigating the directional efforts of small and medium company leaders and members. Research Design, Data, and Methodology - This study selects PPC as an integrated superior concept to establish research models and hypotheses of the influence of PPC on IWB, and the influence of LMX and MMX in these relations. Of the questionnaires distributed, 373 valid questionnaires were collected in total. Results - It was confirmed that the PPC of workers has a statistically significant influence on LMX, MMX, and IWB. Moreover, LMX and MMX have similar influence on worker life satisfaction with life satisfaction and innovative work behavior having different dimensions. Conclusion - To enhance IWB, worker PPC is very important as it has significant influence on the relations with leaders. However, it is also notable that positive relations with colleagues did not influence IWB.

• Journal of Adhesion and Interface
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• v.18 no.1
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• pp.8-12
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• 2017

In this study, waterborne polyurethane was synthesized with polyester polyol, poly(propylene carbonate) (PPC), 4,4-dicyclohexylmethane diisocyanate ($H_{12}MDI$) and dimethylol propionic acid (DMPA) to improve the water resistance. The properties of the synthesized waterborne polyurethane using poly(propylene carbonate) (WPUP) was evaluated through FT-IR, GPC, DSC and UTM. The mechanical properties were increased with the increase in the amount of PPC. When the ratio of polyester polyol to poly(propylene carbonate) is 9:1, the highest water resistance was showed.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.9
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• pp.504-511
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• 2000

The reliability of system is to become a important concern in developed industry. The controller based on the reliability is so important position. PPC(Plant Protection Controller) is for plant protection and human life by fault detection and control action against the transient condition of plant. The protection system of the nuclear reactor and chemical reactor are representative of PPC. This paper presents analysis of PPC relaibility formal problem statement of optimal redundancy based on the reliability for PPC. And the problem is optimized by genetic algorithm, The genetic algorithms is useful algorithm in case of large searching complex gradient existence local minimum. The genetic algorithms is useful algorithm is case of large searching complex gradient existence local minimum. The ability and effectiveness of the proposed optimization is demonstrated by the target reliability of one channel. PPC. using the failure rate based on the MIL-HDBK-217

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.628-636
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• 2010

In this paper, we present a new type high speed parallel multiplier for performing the multiplication of two polynomials using standard basis in the finite fields GF($2^m$). Prior to construct the multiplier circuits, we design the basic cell of vector code generator(VCG) to perform the parallel multiplication of a multiplicand polynomial with a irreducible polynomial and design the partial product result cell(PPC) to generate the result of bit-parallel multiplication with one coefficient of a multiplicative polynomial with VCG circuits. The presented multiplier performs high speed parallel multiplication to connect PPC with VCG. The basic cell of VCG and PPC consists of one AND gate and one XOR gate respectively. Extending this process, we show the design of the generalized circuits for degree m and a simple example of constructing the multiplier circuit over finite fields GF($2^4$). Also, the presented multiplier is simulated by PSpice. The multiplier presented in this paper uses the VCGs and PPCS repeatedly, and is easy to extend the multiplication of two polynomials in the finite fields with very large degree m, and is suitable to VLSL.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.11
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• pp.1792-1801
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• 2008

This study was to develope the pesticide-proof clothes(PPC) for fruit-grower which has been well known over applied agricultural chemicals. The ergonomic evaluation of PPC were tested in two ways. Male adults volunteered the tests to evaluate the safety to pesticide in the field and the thermal comforts in the climate-chamber($30^{\circ}C$, 60%R.H.). PPC were made of 4 different fabrics. Two of them were on the market(coated non-woven and coated nylon). Others were water-repellent treatment and coated waterproof film by developed polyester. The field study was conducted for farmers growing apples to evaluate pesticide exposure. In this experiment, we collected data with patch test on the head, chest, back, right upperarm, right forearm, left thigh and left calf. From the results, the developed PPC showed the more excellent comfort than an existing PPC with nylon coated polyurethane. But the developed PPC of water-repellent fabric was penetrated into the PPC. Therefore, we designed the functional pesticide-proof clothes of 2 different developed polyester fabrics(water-repellent treatment in chest, abdomen, the lower of back, waist, and calf; coated waterproof film in head, shoulder, the upper of back, the crotch, hip, upper arm and thigh).

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.2
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• pp.363-367
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• 2003

Oriental pear was used as treatment of asthma, control of blood pressure tonic medicine vasoaction, diabetes in oriental medicine. In this study, it was investigated that pear phenolic compound effects on cardiovascular system as blood pressure and renin and atrial natriuretic peptide(ANP) in plasma, Cardiac hypertrophy. The experiments were performed on Sprague Dawley rats, 2K1C hypertension model was prepared by constricting the left renal artery with a sliver clip. Animals were then divided into four groups, 5mg/Kg(PPC-A) 10mg/Kg(PPC-B) 15mg/Kg(PPC-c) and control group. Pear phenolic compound solution were supplied with them for 3weeks, a day's interval. The results are that The blood pressure was significantly decreased at 15days in PPC-A group than control group. The plasma ANP was increased in PPC-A and PPC-C group, and cardiac hypertrophy was significantly decrease in PPC-C group compared with control group.