• Title/Summary/Keyword: yield conditions

Search Result 3,129, Processing Time 0.042 seconds

Specification of Governing Factors for High Accurate Prediction of Welding Distortion (용접변형 고정도 예측을 위한 지배인자의 특정)

  • Lee, Jae-Yik;Chang, Kyong-Ho;Kim, You-Chul
    • Journal of Welding and Joining
    • /
    • v.31 no.5
    • /
    • pp.1-6
    • /
    • 2013
  • In carrying out the elastic-plastic analysis, four conditions (equilibrium equation, constitutive equation, condition of compatibility and yield condition) should be satisfied. In welding, the temperature largely changed from a melting temperature to a room temperature. So, yield stress of materials largely changed, too. In particular, yield stress becomes about zero over $700^{\circ}C$. The analysis should be carried out under the condition that equivalent stress generated in temperature increment ${\Delta}T$ did not exceed yield stress of materials at high temperature over $700^{\circ}C$. It should be sufficiently recognized that the obtained results were not reliable if this condition was not satisfied.

Efficiency for extracting icariin from Epimedium koreanum Nakai by temperature and solvent variations

  • Baek, Hum-Young;Lee, Young-Sang
    • Plant Resources
    • /
    • v.6 no.3
    • /
    • pp.221-226
    • /
    • 2003
  • To improve industrial scale extraction method for extraction of icariin from Epimedium koreanum Nakai, the yields under different extracting conditions such as solvent, temperature, duration and solvent to plant material weight ratio were compared. Regarding extracting solution, highest extracts and icariin yield could be achieved when 10% EtOH was used. In case of plant material to extracting solvent ratio, no significant differences could be observed from 1/10 to 1/50, indicating 1/10 was the most efficient. Extracting temperature significantly affected extracts and icariin yields in that 9$0^{\circ}C$ increased the collected extracts and icariin contents up to 29.6% and 0.76%, respectively, compared to 27.2%, 0.33% at 7$0^{\circ}C$. The yield of extracts was less dependent upon extracting temperature compared to icariin yield. Regarding extraction time, 4 hr and 6 hr resulted in high extracts and icariin yield, respectively. We found extracting Epimedium koreanum Nakai in 10 times volume of 10% EtOH for 4 and 6 hr at 9$0^{\circ}C$ seem to be relatively efficient methods for extracts and icariin, respectively.

  • PDF

Effects of Ar-Plasma Treatment in Alkali-Decomposition of Poly(ethylene terephthalate)

  • Seo, Eun-Deock
    • Macromolecular Research
    • /
    • v.11 no.5
    • /
    • pp.387-392
    • /
    • 2003
  • The ablation effects of Ar-plasma treatment and alkali-decomposition behavior in NaOH solution of polyethylene terephthalate (PET) film were investigated. The modifications were evaluated by analysis of atomic force microscopy topographical changes, and by the measurement of decomposition yield in conjunction with heats of formation and electron densities of acyl carbon calculated by Parameterization Method 3 method. It has shown that the alkali-decomposition is hampered by plasma treatment and its decomposition yield is closely related with plasma treatment conditions such as exposure time to plasma. Plasma-treated PET films exhibited lower decomposition yield, compared to that of virgin PET. Increasing plasma exposure time contributes positively to decrease the decomposition yield. It has also shown that the topography of PET surface was affected by the base-promoted hydrolysis as well as Ar-plasma treatments. These behaviors are attributed to the decreased nucleophilicity of acyl carbon damaged by the ablation of Ar-plasma.

A simple limit analysis procedure for reinforced concrete slabs using rigid finite elements

  • Ahmed, H.;Gilbert, M.
    • Structural Engineering and Mechanics
    • /
    • v.84 no.1
    • /
    • pp.129-141
    • /
    • 2022
  • It has previously been proposed that the yield-line method of analysis for reinforced concrete slabs could be automated via the use of rigid finite elements, assuming all deformations occur along element edges. However, the solutions obtained using this approach can be observed to be highly sensitive to mesh topology. To address this, a revised formulation that incorporates modified yield criteria to account for the presence of non-zero shear forces at interfaces between elements is proposed. The resulting formulation remains simple, with linear programming (LP) still used to obtain solutions for problems involving Johansen's square yield criteria. The results obtained are shown to agree well with literature solutions for various slab problems involving uniform loading and a range of geometries and boundary conditions.

Estimating Unsaturated Shear Strength and Yield Load of Compacted Aggregate Sub-base Materials (다져진 보조기층 재료의 불포화 전단강도 및 항복하중 평가)

  • Jeon, Hye-Ji;Park, Seong-Wan
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.31 no.4D
    • /
    • pp.571-576
    • /
    • 2011
  • In general, conventional road pavements are designed under the assumption that the shear strength of geomaterials are under saturated state. In reality, however, most of the pavement geomaterials exists under the unsaturated state. To deal with this gap between saturated and unsaturated conditions, in this paper, unsaturated shear strength was estimated using the results from the triaxial compression test and soil-water characteristics curves. Then, yield loads were assessed using 2-Dimensional finite element method with the selected nonlinear elastic model and the Mohr-Coulomb yield criteria. In addition, various unsaturated condition and surface layer effects on the yield load of granular materials were identified. Therefore, the results demonstrated would provide a possibility to estimate bearing capacity of paved or unpaved roads using unsaturated soil mechanics.

Emulsion Graft Copolymerization of Methyl Methacrylate onto Cotton Fiber (면섬유에 대한 Methyl Methacrylate의 유화 그라프트 중합)

  • Bae Hyun-Sook;Ryu Hyo-Seon;Kim Sung-Reon
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.15 no.3 s.39
    • /
    • pp.271-280
    • /
    • 1991
  • Emulsion graft copolymerization of MMA onto cotton fiber using Ce(IV) salt as an initiator was carried out. Graft yield and graft efficiency were observed according to the kinds and concentrations of emulsifier and polymerization conditions. The physical properties of MMA grafted cotton fabric were investigated. The results of this study were as follows: 1. The heighest graft yield of emulsion graft polymerization occurred at the concentration below cmc of emulsifier, which was different from emulsion polymerization. Nonionic sur- factant as an emulsifier was more effective than anionic one. 2. The highest graft yield was obtained at the initiator concentration $1{\times}10^{-2}mol/l$. The viscometric molecular weight of PMMA was in the order of 106. 3. As reaction time increased, the graft yield increased but the graft efficiency decreased. 4. Elevation of reaction temperature resulted in increase of graft yield. The apparent activation energy of MMA graft polymerization was 4.72 Kcal/mol. 5. Physical properties of MMA grafted cotton fabric varied with increase of grafting. Thickness and stiffness showed a noticeable increase, whereas tensile strength and elongation was slightly increased. Crease recovery increased as the graft yield increase up to $50\%$ and decreased thereafter.

  • PDF

Yield Enhancement Techniques for 3D Memories by Redundancy Sharing among All Layers

  • Lee, Joo-Hwan;Park, Ki-Hyun;Kang, Sung-Ho
    • ETRI Journal
    • /
    • v.34 no.3
    • /
    • pp.388-398
    • /
    • 2012
  • Three-dimensional (3D) memories using through-silicon vias (TSVs) will likely be the first commercial applications of 3D integrated circuit technology. A 3D memory yield can be enhanced by vertical redundancy sharing strategies. The methods used to select memory dies to form 3D memories have a great effect on the 3D memory yield. Since previous die-selection methods share redundancies only between neighboring memory dies, the opportunity to achieve significant yield enhancement is limited. In this paper, a novel die-selection method is proposed for multilayer 3D memories that shares redundancies among all of the memory dies by using additional TSVs. The proposed method uses three selection conditions to form a good multi-layer 3D memory. Furthermore, the proposed method considers memory fault characteristics, newly detected faults after bonding, and multiple memory blocks in each memory die. Simulation results show that the proposed method can significantly improve the multilayer 3D memory yield in a variety of situations. The TSV overhead for the proposed method is almost the same as that for the previous methods.

Assessing the EPIC Model for Estimation of Future Crops Yield in South Korea (미래 작물생산량 추정을 위한 EPIC 모형의 국내 적용과 평가)

  • Lim, Chul-Hee;Lee, Woo-Kyun;Song, Yongho;Eom, Ki-Cheol
    • Journal of Climate Change Research
    • /
    • v.6 no.1
    • /
    • pp.21-31
    • /
    • 2015
  • Various crop models have been extensively used for estimation of the crop yields. Compared to the other models, the EPIC model uses a unified approach to simulate more than 100 types of crops. It has been successfully applied in simulating crop yields for various combinations of weather conditions, soil properties, crops, and management schemes in many countries. The objective of this study was to estimate the rice and maize yield in South Korea using the EPIC model. The input datasets for the 30 types in the 11 categories were created for the EPIC model. The EPIC model simulated rice and maize yields. The performance of the EPIC model was evaluated with the goodness-of-fit measures including Root Mean Square Error (RMSE), Relative Error (RE), Nash-Sutcliffe Efficiency Coefficient (NSEC), Mean Absolute Error (MAE), and Pearson Correelation Coefficient (r). The rice yield showed to more high accuracy than maize yield on four type of method without NSEC. Theses results showed that the EPIC model better simulated rice yields than maize yields. The results suggest that the EPIC crop model can be useful to estimate crop yield in South Korea.

Crop Yield and Crop Production Predictions using Machine Learning

  • Divya Goel;Payal Gulati
    • International Journal of Computer Science & Network Security
    • /
    • v.23 no.9
    • /
    • pp.17-28
    • /
    • 2023
  • Today Agriculture segment is a significant supporter of Indian economy as it represents 18% of India's Gross Domestic Product (GDP) and it gives work to half of the nation's work power. Farming segment are required to satisfy the expanding need of food because of increasing populace. Therefore, to cater the ever-increasing needs of people of nation yield prediction is done at prior. The farmers are also benefited from yield prediction as it will assist the farmers to predict the yield of crop prior to cultivating. There are various parameters that affect the yield of crop like rainfall, temperature, fertilizers, ph level and other atmospheric conditions. Thus, considering these factors the yield of crop is thus hard to predict and becomes a challenging task. Thus, motivated this work as in this work dataset of different states producing different crops in different seasons is prepared; which was further pre-processed and there after machine learning techniques Gradient Boosting Regressor, Random Forest Regressor, Decision Tree Regressor, Ridge Regression, Polynomial Regression, Linear Regression are applied and their results are compared using python programming.

Design and Development of Web-Based Decision Support Systems for Wheat Management Practices Using Process-Based Crop Model (과정기반 작물모형을 이용한 웹 기반 밀 재배관리 의사결정 지원시스템 설계 및 구축)

  • Kim, Solhee;Seok, Seungwon;Cheng, Liguang;Jang, Taeil;Kim, Taegon
    • Journal of The Korean Society of Agricultural Engineers
    • /
    • v.66 no.4
    • /
    • pp.17-26
    • /
    • 2024
  • This study aimed to design and build a web-based decision support system for wheat cultivation management. The system is designed to collect and measure the weather environment at the growth stage on a daily basis and predict the soil moisture content. Based on this, APSIM, one of the process-based crop models, was used to predict the potential yield of wheat cultivation in real time by making decisions at each stage. The decision-making system for wheat crop management was designed to provide information through a web-based dashboard in consideration of user convenience and to comprehensively evaluate wheat yield potential according to past, present, and future weather conditions. Based on the APSIM model, the system estimates the current yield using past and present weather data and predicts future weather using the past 40 years of weather data to estimate the potential yield at harvest. This system is expected to be developed into a decision support system for farmers to prescribe irrigation and fertilizer in order to increase domestic wheat production and quality by enhancing the yield estimation model by adding influence factors that can contribute to improving wheat yield.