AbstractAs construction projects have significantly increased in size and become more complicated, the number of claims and dispute cases between participating parties during the construction work ...have been continuously increasing. To prevent such claims and disputes, the participants need to be assured of their contractual positions and rights based on contract facts. For this reason, the process of writing and reviewing the contracts for construction work is crucial. Most international construction projects require contract management teams to review all the possible risks in the contracts during the bidding periods. However, it is very difficult to review a vast number of contracts in a short period of time. Therefore, in this study, we proposed an automatic model of contract-risk extraction based on natural language processing (NLP) that can automatically detect the poisonous clauses of the contract in order to support contract management for construction companies (contractors). In validating the performance of the automatic model developed in this study, we found that the precision and recall were both 81.8% compared with manual review. This study is meaningful since a model has been developed that can carry out a preemptive contract-risk review.
AbstractDefining, measuring, and dealing with contractual risks are crucial for successful construction projects because the contractual risks can lead to serious claims and disputes. In general, ...construction participants make a stipulation regarding their roles and responsibilities by contracting in order to prevent such claims and disputes. A common practice for preparing construction contracts is to modify the standard contract forms to reflect the interests of the given project from the owner’s perspective. In this process, however, favorable clauses that may be beneficial to the contractor are often modified or even removed, causing significant potential risks to the contractor. Therefore, an in-depth review of contract terms and conditions is required to avoid future risks. This study presents a new proactive risk assessment model to identify missing contractor-friendly clauses in the owner’s modified contract conditions from the contractor’s point of view. A case study is used to demonstrate the proposed framework, and real-world project cases were analyzed to understand what type of contractor-friendly clauses would likely be omitted in the owner’s modified contract. In this study, the developed model builds on rule-based natural-language processing (NLP) to analyze unstructured text data through preprocessing, syntactic analysis, and semantic analysis. The proposed data-driven risk assessment model is expected to reduce the extent of human errors by (1) identifying potential contractual risks that could arise disputes; and (2) supporting to develop an appropriate response strategy for the given risks.
Coprecipitation effortlessly fabricated nickel hexacyanoferrate (NiHCF) with outstanding rate capability and stability for aqueous batteries. Citrate‐aided coprecipitation decelerated the ...crystallization, assembling cubic‐shaped powder based on separation between nucleation and growth. This study revealed that coprecipitation temperature determined the electrochemical performance. With lower temperatures, smaller particles with more water were formed by predominant nucleation, resulting in low crystallinity and capacity of 58 mAh g−1. Expanded surface area reduced electrode/electrolyte interface charge‐transfer resistance and showed excellent rate capability (79 % of initial capacity at 100 C‐rate). However, poor cyclability was obtained. At elevated temperatures, nuclei growth and dehydration occurred, and thus highly crystalline large particles were formed. In turn, NiHCF delivered excellent capacity of 76 mAh g−1 at 1 C‐rate but exhibited inferior rate performance because of longer diffusional path. Meanwhile, normal coprecipitation at 70 °C induced irregular‐shaped tiny particles, presenting 93 % retention of initial capacity at 100 C‐rate.
A matter of temperature: The temperature of the citrate‐aided coprecipitation determines the electrochemical performance of nickel hexacyanoferrate. With lower temperatures, multiple smaller particles are formed with an extended surface, resulting in excellent rate capability. A higher temperature forms highly crystalline larger particles with a higher specific capacity.
•Pyrolysis of PVDC resin with ZnO undergoes both activations and templating at 950 °C.•HCl from PVDC resin reacts with ZnO to form ZnCl2, leading to first activation.•ZnO reduces to Zn with oxidizing ...carbon with pore creation, named as second activation.•Chemical activation of PVDC resin with ZnO does not require post-washing.•ZnO sites act as a template during activation, leaving large pores.
Activated carbon, with its porous morphology and extremely high surface area, maintains the exclusive position as an electrode material in supercapacitors owing to its low manufacturing cost. Although its surface area can be boosted using a chemical etchant to create nanoscale pores, the use of chemicals requires a post-washing of the material to eliminate impurities. Herein, the activation of polyvinylidene chloride (PVDC) resin using ZnO chemical is described to prepare porous activated carbon materials for use as supercapacitor electrodes. During heat-treatment of a 1:1 mass ratio of PVDC resin:ZnO at 950 °C, activation and templating processes consecutively take place to produce porous carbon. Between 140 °C and 600 °C, ZnCl2 formed from the conversion of ZnO chemically activates the carbon with creating micropores. Above 800 °C, unreacted ZnO from the initial activation is reduced to Zn upon oxidation of the carbon with the additional micropore creation. Above 907 °C the Zn evaporates to leave activated carbon with no impurities. Through this process, the sites initially occupied by ZnO would turn to the pores by templating. With a rationally-designed ZnO ratio, porous carbon can be produced without washing. The activated carbon exhibits a high quinone content that reacts with H+ ions, with a high specific capacitance of 219 F g−1 in 1 M H2SO4 based on pseudocapacitance. However, the rate performance of this material is 55% due to the slow kinetics of the charge transfer reaction. On the contrary, a high quaternary-N content increases the rate capability of the material in 6 M KOH, where the double-layer mostly contributes toward charge storage.
AbstractThis study presents a method for estimating construction costs, even when dealing with limited and unreliable data, to enhance decision-making in the early project stages. Owners, ...particularly in green building projects, often face challenges due to the scarcity of usable data, making cost estimation a complex task. They struggle to differentiate between costs associated with existing buildings and green buildings. To address this issue, we introduce a novel approach that leverages conditional tabular generative adversarial networks (CTGANs) for data augmentation, overcoming the limitations of relying solely on historical data. This involves training an artificial neural network (ANN)–based model using synthetic data, effectively addressing the scarcity and imbalance present in the original small data set. Compared to models trained exclusively on the original data set, our approach yielded a remarkable reduction of approximately 66% in root-mean-square error (RMSE), while increasing the validity from 0% to 15.09%. This study not only improves construction cost estimation but also facilitates more informed decision-making for owners, even in cases with limited and unreliable data, ultimately contributing to the efficiency of the construction project planning process.
It has been reported that Korean Red Ginseng has been manufactured for 1,123 y as described in the GoRyeoDoGyeong record. The Korean Red Ginseng manufactured by the traditional preparation method has ...its own chemical component characteristics. The ginsenoside content of the red ginseng is shown as Rg1: 3.3 mg/g, Re: 2.0 mg/g, Rb1: 5.8 mg/g, Rc:1.7 mg/g, Rb2: 2.3 mg/g, and Rd: 0.4 mg/g, respectively. It is known that Korean ginseng generally consists of the main root and the lateral or fine roots at a ratio of about 75:25. Therefore, the red ginseng extract is prepared by using this same ratio of the main root and lateral or fine roots and processed by the historical traditional medicine prescription. The red ginseng extract is prepared through a water extraction (90°C for 14–16 h) and concentration process (until its final concentration is 70–73 Brix at 50–60°C). The ginsenoside contents of the red ginseng extract are shown as Rg1: 1.3 mg/g, Re: 1.3 mg/g, Rb1: 6.4 mg/g, Rc:2.5 mg/g, Rb2: 2.3 mg/g, and Rd: 0.9 mg/g, respectively. Arginine-fructose-glucose (AFG) is a specific amino-sugar that can be produced by chemical reaction of the process when the fresh ginseng is converted to red ginseng. The content of AFG is 1.0–1.5% in red ginseng. Acidic polysaccharide, which has been known as an immune activator, is at levels of 4.5–7.5% in red ginseng. Therefore, we recommended that the chemical profiles of Korean Red Ginseng made through the defined traditional method should be well preserved and it has had its own chemical characteristics since its traditional development.
Summary
Cobalt hexacyanoferrate (CoFe(CN)6; CoHCF) is coprecipitated as a cathode material in an Na‐ion aqueous battery with varying solution temperatures of 5°C, 25°C, 50°C, and 70°C to tailor the ...particle size and defect content. At a low temperature, the small cubic particle is prepared with high Fe vacancies and low Na amounts. Conversely, an elevated temperature results in the enlarged particle with lower Fe vacancies and high Na amounts. Meanwhile, the lattice parameter is extended at a high temperature based on the Co2+ evolution with a larger ionic radius than that of the Co3+ ion at the Co site. Contrary with the expectations, a lower specific capacity is obtained for the highly crystalline structure at high temperature due to the evolution of the irreversible redox‐inactive Co2+. The low temperature of 5°C confers an excellent rate capability, capacity retention of 89% at 20 times faster charging rate, based on the smaller particles and relieved distortion in cycling. The shorter diffusion path for Na intercalation due to the fine powder enables a faster charging process. Higher Fe vacancies induced at lower temperature limit Na accommodation, yielding a reduced distortion. The coprecipitation at low temperature enhances the rate performance and cyclability, sacrificing the capacity.
Novelty Statement
High temperature builds the large particle with low Fe vacancies and high Na amounts.
High temperature derives the extended lattice constant due to Co2+ evolution in CoHCF.
Evolution of the irreversible redox‐inactive Co2+ degrades the specific capacity.
Low temperature enhances rate performance due to small powder and relaxed distortion.
High rate performance and cyclability at low temperature sacrifices the capacity.
Cobalt hexacyanoferrate (CoFe(CN)6; CoHCF) is coprecipitated as a cathode material in an Na‐ion aqueous battery with varying solution temperatures of 5°C‐70°C. High temperature evolves the irreversible redox‐inactive Co2+, degrading the specific capacity. Low temperature enhances the rate performance due to the small powder and relaxed distortion, sacrificing the capacity.
Highly porous activated carbon is an essential electrode material for high-energy-density supercapacitors, since the electrical charge is stored through electrolyte-ion adsorption on an electrode ...with high surface area. Here, we report the facile and simple synthesis of an activated carbon with tailored porosity from the blended polymers with different thermal stabilities, i.e., polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE). Through a thermal treatment (900 °C) under inert atmosphere, PVDF is simply transformed into highly microporous (<2 nm) carbon, owing to the release of the combined hydrogen and fluoride. The microporous surface morphology reduces the specific capacitance at high discharging rates. Meanwhile, the PTFE is completely evaporated to the C2F4 gas at 900 °C under an inert environment. The mixed polymer with a specific ratio (PVDF:PTFE = 2:1) is carbonized to porous carbon with a highly accessible surface area. The mesopore (2–50 nm) formed via C2F4-gas escape from PTFE facilitates ionic transfer to the surface at a rapid discharging rate with the high specific capacitance, i.e., 99 F g−1. Compared with the PVDF-alone derived carbon, the carbon derived from the appropriately mixed precursors exhibits a 19 % higher specific capacitance and increased capacity retention at a 10-fold faster discharging rate.
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