2,466 research outputs found
Energy Efficiency of Seasonal Solar Thermal Energy Storage System for Greenhouse Heating
Seasonal Thermal Energy Storage (STES) is widely researched for having benefits in that it utilizes excess energy which would be wasted otherwise. The purpose of this study is to analyze energy efficiency of seasonal solar thermal energy system as heating system for greenhouses and compare it with conventional variable air volume (VAV) heating system. Greenhouse was chosen as a simulation model because it requires constant and stable heating through winter season to extend growing season and also because greenhouse can provide enough area to install solar collectors and heat storage tanks. The proposed seasonal solar thermal energy storage system consists of solar thermal collector, fully mixed heat storage tank, and VAV system. Energy simulation was conducted in two steps: heat storing in summer season, and heating in winter season. For greenhouses with area sizing 1600 m2, solar thermal collector of 1250 m2 and heat storage tank of 2000 m3 were designed. TRNSYS 17 and engineering equation solver (EES) were implemented for simulation and calculation of the systems thermal data. Simulation results showed the tank water temperature rising up to optimal temperature (95 oC) before heating season, and STES heating contributed to 55% of total heating load. Consequently, 30% of total heating cost was cut down showing energy efficiency of seasonal solar thermal energy storage system
Water absorption and maintenance of nanofiber cellulose production by Gluconacetobacter rhaeticus TL-2C
Physiochemical properties of bacterial cellulose producing by Gluconacetobacter rhaeticus TL-2C was investigated for confirming its possibility as wound care dressing material. Scanning electron micrograph showed that the diameter of bacterial cellulose fiber was 40 to 50 nm. Solid state 13C nuclear magnetic resonance (NMR) data showed that the bacterial cellulose had amorphous peak of C-4 and C-6 and the crystallinity index of bacterial cellulose was 75.4. Water absorption ability of bacterial cellulose was 19-fold higher than α-cellulose. Bacterial cellulose had 2-fold higher water maintenance ability than α-cellulose.Key words: Bacterial cellulose, Gluconacetobacter rhaeticus, nanofiber, water absorption
Competing states for the fractional quantum Hall effect in the 1/3-filled second Landau level
In this work, we investigate the nature of the fractional quantum Hall state
in the 1/3-filled second Landau level (SLL) at filling factor (and
8/3 in the presence of the particle-hole symmetry) via exact diagonalization in
both torus and spherical geometries. Specifically, we compute the overlap
between the exact 7/3 ground state and various competing states including (i)
the Laughlin state, (ii) the fermionic Haffnian state, (iii) the
antisymmetrized product state of two composite fermion seas at 1/6 filling, and
(iv) the particle-hole (PH) conjugate of the parafermion state. All these
trial states are constructed according to a guiding principle called the
bilayer mapping approach, where a trial state is obtained as the
antisymmetrized projection of a bilayer quantum Hall state with interlayer
distance as a variational parameter. Under the proper understanding of the
ground-state degeneracy in the torus geometry, the parafermion state can
be obtained as the antisymmetrized projection of the Halperin (330) state.
Similarly, it is proved in this work that the fermionic Haffnian state can be
obtained as the antisymmetrized projection of the Halperin (551) state. It is
shown that, while extremely accurate at sufficiently large positive Haldane
pseudopotential variation , the Laughlin state loses its
overlap with the exact 7/3 ground state significantly at . At slightly negative , it is shown that the
PH-conjugated parafermion state has a substantial overlap with the exact
7/3 ground state, which is the highest among the above four trial states.Comment: 22 pages, 5 figure
Interpreting positive signs of the supraspinatus test in screening for torn rotator cuff.
The purpose of this study was to investigate the validity of the supraspinatus test as a screening test for detecting torn rotator cuff and to determine what its valuable positive signs were. Both the empty-can test and full-can test were performed on 200 shoulders diagnosed by magnetic resonance imaging (MRI)-and in some cases, surgical findings-to have full-thickness or partial-thickness torn rotator cuff s, or no tear in the rotator cuff . During the maneuver, the presence of pain or weakness or both pain and weakness were recorded as positive signs, and the distribution of these signs were analyzed according to the degree of tear. The predictive values were calculated in 2 ways by considering (1) only full-thickness tears as tears and (2) both full- and partial-thickness tears as tears. The 2 tests and the 2 ways of considering partial-thickness tears were compared. Pain and weakness were severity-dependent, and the empty-can test had a higher incidence of pain. The sensitivities of the 2 supraspinatus tests in all positive signs were higher when including partial-thickness tears in the tear group ; however, their specificities were higher when excluding partial-thickness tears. Both pain and weakness were interpretive for the supraspinatus test, and both tests were sensitive to full- and partial- thickness tears and specific for full-thickness tears
Paleomagnetism and U-Pb geochronology of the late Cretaceous Chisulryoung Volcanic Formation, Korea: tectonic evolution of the Korean Peninsula
Advanced Harmony Search with Ant Colony Optimization for Solving the Traveling Salesman Problem
We propose a novel heuristic algorithm based on the methods of advanced Harmony Search and Ant Colony Optimization (AHS-ACO) to effectively solve the Traveling Salesman Problem (TSP). The TSP, in general, is well known as an NP-complete problem, whose computational complexity increases exponentially by increasing the number of cities. In our algorithm, Ant Colony Optimization (ACO) is used to search the local optimum in the solution space, followed by the use of the Harmony Search to escape the local optimum determined by the ACO and to move towards a global optimum. Experiments were performed to validate the efficiency of our algorithm through a comparison with other algorithms and the optimum solutions presented in the TSPLIB. The results indicate that our algorithm is capable of generating the optimum solution for most instances in the TSPLIB; moreover, our algorithm found better solutions in two cases (kroB100 and pr144) when compared with the optimum solution presented in the TSPLIB
CONSENSUS DEFINITION-BASED CUTOFFS OF HIGH ON-TREATMENT PLATELET REACTIVITY: VALIDATION BETWEEN LIGHT TRANSMITTANCE AND MULTIPLE ELECTRODE AGGREGOMETRIES
Characteristics of the Korean stock market correlations
In this study, we establish a network structure of the Korean stock market,
one of the emerging markets, with its minimum spanning tree through the
correlation matrix. Base on this analysis, it is found that the Korean stock
market doesn't form the clusters of the business sectors or of the industry
categories. When the MSCI (Morgan Stanley Capital International Inc.) index is
exploited, we found that the clusters of the Korean stock market is formed.
This finding implicates that the Korean market, in this context, is
characteristically different form the mature markets.Comment: 11 pages, 3 figures, revised on June 200
Effect of software version and parameter settings on the marginal and internal adaptation of crowns fabricated with the CAD/CAM system
Objective This study investigated the marginal and internal adaptation of individual dental crowns fabricated using a CAD/CAM system (Sirona’s BlueCam), also evaluating the effect of the software version used, and the specific parameter settings in the adaptation of crowns.Material and Methods Forty digital impressions of a master model previously prepared were acquired using an intraoral scanner and divided into four groups based on the software version and on the spacer settings used. The versions 3.8 and 4.2 of the software were used, and the spacer parameter was set at either 40 μm or 80 μm. The marginal and internal fit of the crowns were measured using the replica technique, which uses a low viscosity silicone material that simulates the thickness of the cement layer. The data were analyzed using a Friedman two-way analysis of variance (ANOVA) and paired t-tests with significance level set at
Natural Food Additives and Preservatives for Fish-Paste Products: A Review of the Past, Present, and Future States of Research
Fish-paste products, also known as fish cakes or surimi-based products, are worldwide favorites. Surimi, a wet protein concentrate of fish muscle, is used as an intermediate raw material to produce surimi seafood. The flavor, texture, taste, shelf-life, and market value of surimi-based products depend on the source of the fish meat, type of applied heat treatment, and additives used to prepare the surimi. While preparing surimi with chemical additives, several problems have been observed, such as a lack of unique characteristics, inferior acceptability, and poor functionality. Various types of fish-paste products have been developed by using different ingredients (e.g., vegetables, seafood, herbs and oriental medicines, grains and roots including carrots, and functional food materials). However, a systematic review of fish-paste products prepared using natural food additives has not yet been performed. Therefore, the quality characteristics of fish-paste products and their functionalities were elucidated in this study. With the increasing demand for surimi seafood products, the functional properties, physiochemical properties, and shelf-life of surimi-based products need to be improved. This review will aid the preparation of new value-added products in the surimi industry
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