A concept to define a quantitative measure of mixture state

Mixing is a mechanical operation to distribute components evenly in a plane or a space. Composite molding and textile manufacturing industries are routinely taking advantage of mixing operations in order to distribute raw materials uniformly or in a specific way during composite molding or textile producing processes. Key issues to identify any mixed state are (1) the time needed to accomplish through mixing (the time scale) and (2) the extent of the homogeneity of the mixture in a plane (the length scale). In this paper, a new concept of mixture status is focused on the length scale. The goal to derive a new concept of mixture status is to establish a measure to describe the mixed extent of a mixture consisting of two components, derived from clump size and clump distribution. To verify the usefulness of the newly conceived “Mixedness Index”, the suggested definition was compared with the existing coefficient of variation (CV) method based on simulation and experiments. Results showed a reasonable relationship between the Mixedness Index and observation, demonstrating the feasibility of the proposed Mixedness Index for industrial applications.     

A specific colorimetric signaling of biological thiolsbased on intermolecular n-π charge transfer interaction

A new charge-transfer (CT) complex, consisting of 2,3-dichloro-5-nitro-1,4-naphthoquinone and biothiols such as cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) has been designed to sensing biothiols. The method is selective and sensitive for biothiols detection without the interference of other amino acids.     

Effects of interspecific competition on the growth and competitiveness of five emergent macrophytes in a constructed lentic wetland

To evaluate the performance of new rice establishment methods viz., system of rice intensification (SRI) and integrated crop management (ICM), a field study was conducted during 2008–11 in South Garo Hills, Meghalaya, foot hills of Eastern Himalayas, India. Field demonstrations were undertaken during wet seasons of 2008–11 and socio-economic information in the context of farmer’s realities were obtained during 2010–11 using a well structured questionnaire administered to 134 farmers. The results indicated that the average higher productivity of rice under SRI and ICM demonstration was 209.9 and 185.4 %, respectively, over conventional rice culture (CRC). The SRI and ICM methods of rice cultivation could save seeds (97.56 and 60.98 %), saving water (78.05 and 63.66 %), reduce cost (70.33 %), higher yield etc. compared to CRC. The main reasons for non-adoption of SRI/ICM was related to involvement of more efforts, faith towards traditional practices, ignorance and lack of knowledge on scientific water management. The net-return of $816.69, $706.63 and $51.48/ha was realized under SRI, ICM and CRC, respectively. The co-efficient of multiple determinations (R ²) of the production function was 0.695 in SRI, 0.714 in ICM and 0.734 in CRC which indicated that about 69.5, 71.4 and 73.4 % of the variation in rice productivity under SRI, ICM and CRC, respectively were explained by the independent variable and remaining 30.5, 28.6 and 26.6 %., respectively in SRI, ICM and CRC were as a result of non-inclusion of some explanatory variables as well as other factors outside the farmers control.     

Synthesis and properties of Nylon 4/5 copolymers for hydrophilic fibers

Nylon 4, which can be synthesized by anionic ring-opening polymerization, has good mechanical properties and a very high affinity for water owing to its high polarity. On the other hand, despite its high melting temperature, the polymer has not been commercialized because of its low thermal stability. In this study, copolymerization of 2-pyrrolidone (C4) with 2-piperidone (C5) was performed to reduce the melting temperature of Nylon 4 homopolymer. The copolymerization reaction was controlled by changing the comonomer content, catalyst content, temperature, initiator content, and reaction time. The Nylon copolymers were characterized by ¹H-nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. The hydrophilic properties of Nylon 4 and its copolymers were evaluated by surface free energy analysis and moisture regain measurement. The intrinsic viscosity and polymerization yield of Nylon 4 increased with increasing catalyst concentration until 5 mole% and decreased with further increases in catalyst loading. The proton NMR spectrum revealed the composition of the Nylon 4/5 copolymer to be 62.5 % C4 moiety at a 5:5 comonomer feed ratio. The melting temperature of the Nylon 4/5 copolymers decreased considerably according to the composition. The moisture regain of the Nylon 4/5 copolymer was higher than 6.4 % even at 77.3 % C4 in composition.     

Thermal and mechanical properties of modified CaCO3 filled poly (ethylene terephthalate) nanocomposites

Poly(ethylene terephthalate) (PET)/CaCO₃ and PET/modified-CaCO₃ (m-CaCO₃) nanocomposites were prepared by melt blending. The morphology indicated that m-CaCO₃ produced by reacting sodium oxalate and calcium chloride, was well dispersed in PET matrix and showed good interfacial interaction with PET compared to CaCO₃. No significant differences in the thermal properties such as, glass transition, melting and degradation temperatures, of the nanocomposites were observed. The thermal shrinkage of PET at 120 °C was 10.8 %, while those of PET/CaCO₃ and PET/m-CaCO₃ nanocomposites were 2.9–5.2 % and 1.2–2.8 %, respectively depending on filler content. The tensile strength of PET/CaCO₃ nanocomposite decreased with CaCO₃ loading, whereas that of PET/m-CaCO₃ nanocomposites at 0.5 wt% loading showed a 17 % improvement as compared to neat PET. The storage modulus at 120 °C increased from 1660 MPa for PET to 2350 MPa for PET/CaCO₃ nanocomposite at 3 wt% loading, and 3230 MPa for PET/m-CaCO₃ nanocomposite at 1 wt% loading.     

Estimating water footprint of paddy rice in Korea

The purpose of this article is to examine the issues of low grain self-sufficiency and the high portion of agricultural water use in South Korea, and to trace the water footprint (WF) of rice products. In this study, different types of water use were described as green, blue, and gray WFs and were analysed using suitable estimation methods to determine irrigation water requirements in South Korea. Virtual water (VW) import and export of rice product were calculated based on international trade statistics during 2004–2009, and the WF of the national consumption was estimated. The WF of rice was 844.5 m³/ton, and green, blue, and gray water accounted for 294.5, 501.6, and 48.4 m³/ton, respectively. The VW import and export were 404.17 and 2.03 Mm³/year, respectively, against an import 199.5 times that of the export. Three countries (China, USA, and Thailand) accounted for over 95 % of the total VW imports of rice products into South Korea. The total WF was 5,712.08 Mm³/year, thus the WF per capita for rice was estimated at 118.1 m³/year. The internal WF of rice consumption was 5,308.05 Mm³/year, and the external WF was 404.03 Mm³/year. The WF of total agricultural water use should be analyzed for sustainable agricultural production and water management, and these results should be applied in establishing long-term policies for agricultural water resources.     

Climate change’s impact on irrigation system and farmers’ response: a case study of the Plaichumpol Irrigation Project,Phitsanulok Province,Thailand

The Plaichumpol Irrigation Project, in Nan Basin of Thailand, is selected as a case study of impact study, where farmers depended on both surface and groundwater sources (especially in the dry year), to assess the impact on irrigation systems. The study used the MRI-GCM data to project the future climate condition and assess the impact on irrigation systems focusing on water shortage and groundwater pumping aspects in the selected consecutive dry years. The responses from farmers on the impact and adaptation were also gathered via site interviews and analyzed. Based on the bias-corrected MRI-GCM data, the annual rainfall in Nan Basin will decrease in the near future (2015–2039), compared with the past average data (1979–2006), while the rainfall will increase in the far future (2075–2099) compared with past. Water supply from dam will decrease in wet season and dry season, while water demand in both of near future and far future will increase in wet season and dry season. Less water shortage and groundwater pumping in both near-future and far-future periods are expected in the future consecutive dry years compared with the past, though the groundwater is still an important supplementary irrigation water source in the dry year. From the field interview, the farmers are ready to adapt to the changing situations and join in the water use meeting to follow up with irrigation officers about the adjustment of plant calendar and water allocation due to the climate change and to prepare adaptation measures as necessary.     

Evaluation of technologies for sequestering carbon in agricultural land by using organic filter underdrains

Technology for storing carbon in the subsoil of agricultural land using organic filter materials in underdrains was evaluated as an activity for sequestering CO₂ to mitigate global warming. First, the quantity of carbon remaining in wood chips and rice husks in underdrains was determined over 11 years after construction. Moreover, the quantity of CO₂ emissions from the construction of two underdrain types was calculated. Then, a survey was conducted to investigate the effect on greenhouse gas emissions of the filter material. The results indicate that greenhouse gas emissions would not increase. The quantity of storage carbon in the wood chip filter material of underdrains during their 15-year service life was estimated to be 6.76 tCO₂eq ha^?1. Rice husks, in contrast, were found ineffective in storing carbon. Therefore, the selection of the filter material for underdrains is important. The value of storage carbon in the wood chip filter material is similar to the amount of carbon sequestered by no-till farming, which is now being implemented as a global warming countermeasure based on soil management in agricultural land.     

SWAT modeling of best management practices for Chungju dam watershed in South Korea under future climate change scenarios

Suitable and practicable best management practices (BMPs) need to be developed due to steadily increasing agricultural land development, intensified fertilization practices, and increased soil erosion and pollutant loads from cultivated areas. The soil and water assessment tool model was used to evaluate the present and future proper BMP scenarios for Chungju dam watershed (6,642 km²) of South Korea, which includes rice paddy and upland crop areas. The present (1981–2010) and future (2040s and 2080s) BMPs of streambank stabilization, building recharge structures, conservation tillage, and terrace and contour farming were examined individually in terms of reducing nonpoint source pollution loads by applying MIROC3.2 HiRes A1B and B1 scenarios. Streambank stabilization achieved the highest reductions in sediment and T-N, and slope terracing was a highly effective BMP for sediment and T-P removal in both present and future climate conditions.     

Evaluation of MODIS NDVI and LST for indicating soil moisture of forest areas based on SWAT modeling

This study examined the capability of remotely sensed information gained using the terra moderate resolution imaging spectroradiometer (MODIS) normalized difference vegetation index (NDVI) and land surface temperature (LST) to explain forest soil moisture. The soil and water assessment tool (SWAT) was used for the analysis. Nine years (2000–2008) of monthly MODIS NDVI and LST data from a 2,694.4 km² watershed consisting of forest-dominant areas in South Korea were compared with SWAT simulated soil moisture. Before the analysis, the SWAT model was calibrated and verified using 9 years of daily streamflow at three gauging stations and 6 years (2003–2008) of daily measured soil moisture at three locations within the watershed. The average Nash–Sutcliffe model efficiency during the streamflow calibration and validation was 0.72 and 0.70, respectively. The SWAT soil moisture showed a higher correlation with MODIS LST during the forest leaf growing period (March–June) and with MODIS NDVI during the leaf falling period (September–December). Low correlation was observed in the year of frequent rains, regardless of the leaf periods.