• 지구물리와물리탐사
• /
• 제19권3호
• /
• pp.121-130
• /
• 2016

다양한 지름의 암석코어에 대해 비교적 간편하고 정확하게 열전도도를 측정할 수 있는 divided bar형 열전도도 측정 시스템인 PEDB (potable electronic divided bar system)를 도입 이용하여 열전도도 측정시 고려해야 할 요소에 대해 검토하였다. 또한, 지열조사를 위해 울릉도에서 채취한 70개의 코어시료에 대해 적용하고 그 특성을 살펴보았다. 열전도도 측정에 있어서 실내온도의 변화가 가장 큰 영향을 미치므로 되도록 실내온도의 변화가 적거나 항온 환경에서 측정하는 것이 바람직하다. 열원(heat source)의 온도, 안정된 상태에서 평균하는 온도의 구간 등에 의한 영향은 실내온도 변화에 비해 미미하다. 열접촉 보조제인 바셀린을 사용하면 시편의 열전도도가 다소 높게 평가되고 특히 접촉면이 고르지 않은 암석시편에서는 그 차이가 더 크게 나타난다. 하나의 시편에 대해 반복 측정할 때, 실내온도가 $1^{\circ}C$ 이내로 유지된다면 표준시편에서는 ${\pm}0.3%$ 이내, 암석시편에서는 ${\pm}4%$ 이내의 좋은 반복성을 얻을 수 있다. 울릉도의 두 지열 조사공에서 얻은 암석코어의 열전도도는 심도 증가에 따라서 대체로 열전도도가 커지는 경향이 있으나 암종 변화와 특별한 상관성을 보이지는 않았다.

• 생태와환경
• /
• 제49권1호
• /
• pp.51-61
• /
• 2016

본 연구는 서울시 노원구에 위치한 두 도시공원 (노해근린공원, 상계근린공원)의 탄소수지를 정량하고 인접한 자연공원인 불암산 신갈나무림을 대상으로 동일한 조사를 수행하여 그 개선방안을 찾기 위해 수행하였다. 순생산량(NPP)은 상대생장법을 적용하여 측정하였고, 토양호흡량은 EGM-4를 이용하여 측정하였다. 노해근린공원과 상계근린공원에 조성된 식생의 순생산량은 각각 $5.4\;ton\;C\;ha^{-1}yr^{-1}$와 $4.8\;ton\;C\;ha^{-1}yr^{-1}$로 나타났고, 불암산 신갈나무군락의 순생산량은 $6.3\;ton\;C\;ha^{-1}yr^{-1}$로 나타났다. 연간 종속영양생물 토양호흡량은 노해근린공원과 상계근린공원에서 각각 $5.3\;ton\;C\;ha^{-1}yr^{-1}$와 $3.4\;ton\;C\;ha^{-1}yr^{-1}$로 측정되었고, 불암산 신갈나무군락의 토양호흡량은 $4.1\;ton\;C\;ha^{-1}\;yr^{-1}$로 측정되었다. 공원구역에서 나지가 차지하는 면적을 반영하여 산정한 노해근린공원과 상계근린공원의 순생태계생산량은 각각 $-1.0\;ton\;C\;ha^{-1}yr^{-1}$와 $0.6\;ton\;C\;ha^{-1}yr^{-1}$로 나타났고, 불암산 신갈나무군락의 순생태계생산량은 $2.3\;ton\;C\;ha^{-1}yr^{-1}$로 나타났다. 순생태계생산량 정보에 근거하면 노해근린공원은 탄소배출원으로 분류되었다. 반면에 상계근린공원은 탄소흡수원으로 구분되었지만 그 역할은 자연식생과 비교해 크게 낮은 것으로 평가되었다. 도시공원의 낮은 순생태계생산량은 자연림과 비교해 낮은 순생산량과 탄소배출 기능이 있는 나지를 넓게 배정한 것에 기인하는 것으로 나타났다.

• 한국토양비료학회지
• /
• 제46권6호
• /
• pp.652-658
• /
• 2013

A huge number of greenhouse soils in Korea have accumulated mineral elements which induce many nutritional and pathological problems. The present study was performed to the effects of the reduced fertilization on plant growth, and uptake and partitioning of minerals (N, P, K) and soluble carbohydrates using highly minerals-accumulated farmer's greenhouse soil. On the basis of the recommended application for tomato crop, the application rates of N, P and K were 110(50%)-5.2(5%)-41.5(35%)kg $ha^{-1}$, respectively, using Hoagland's nutrient solution. Tomato growth rates during the whole experiment were not significant between treatments, but it was found that a decrease in daily growth represented after 60 days of treatment (DAT). The reduced application led to a drastic decrease in the concentration of N, P and K in fruits, and, thus, this resulted in lower uptake after 40 DAT. The lower phloem export and utilization of soluble carbohydrates caused an accumulation of extra-carbohydrates in leaves, stems and fruits in the reduced application. The reduced fertilization induced the capture of N, P and K in leaves and of soluble carbohydrates in stems compared to the conventional application. In this study, we suggest that it is possible to delay the first fertigation time in minerals-accumulated soils without an adverse impact on crop growth, but it is necessary to regularly monitor mineral status in soil to ensure a balanced uptake, synthesis and partitioning of minerals and carbohydrates.

• 수산해양교육연구
• /
• 제16권2호
• /
• pp.257-270
• /
• 2004

The two-phase closed thermosyphon is a heat transfer device capable of transfer large quantities of heat from a source to a sink by taking advantage of the high heat transfer rates associated with the evaporation and condensation of a working fluid within the device. A study was carried out with the performance of the heat transfer of the thermosyphon having 50, 60, 70, 80, 90 internal micro grooves in which boiling and condensation occur. A plain thermosyphon having the same inner and outer diameter as the grooved thermosyphon is also tested for comparison. Water, methanol and ethanol have been used as the working fluids. The liquid filling as the ratio of working fluid volume to total volume of thermosyphon, the inclination angle, micro grooves and operating temperature have been used as the experimental parameters. The heat flux and the boiling and the condensation heat transfer coefficient and overall heat transfer coefficient at the condenser and evaporator zone are estimated from the experimental results. The experimental results have been assessed and compared with existing correlations. Imura's and Kusuda's correlation for boiling showed in good agreement with experimental results within ${\pm}20$％ in plain thermosyphon. The maximum heat transfer rate was obtained when the liquid fill ratio was about 25%. The high heat transfer coefficient was found between 25o and 30o of inclination angle for water and between 20o and 25o for methanol and ethanol. The relatively high rates of heat transfer have been achieved in the thermosyphon with internal micro grooves. The micro grooved thermosyphon having 60 grooves shows the best heat transfer coefficient in both condensation and boiling. The maximum enhancement (i.e. the ratio of the heat transfer coefficients of the micro grooved thermosyphon to plain thermosyphon) is 2.5 for condensation and 2.3 for boiling.

• 한국초지조사료학회지
• /
• 제39권2호
• /
• pp.75-80
• /
• 2019

Oilseed rape is known to crop having low nitrogen use efficiency (NUE) but requires high levels of N fertilizer. NUE is associated with N remobilization from source to sink organ, consequently affects seed yield. Remobilization of leaf N is also related to transport of C/N metabolites in phloem. However, interaction between seed yield and phloem transport was not fully documented. In response to seed yield, N and C metabolites and their transport into seed from bolting to pod filling stage investigated in two contrasting genotypes (Capitol and Pollen) cultivated under ample (HN) or limiting nitrate (LN) supply. Seed yield was significantly reduced in N limitation and its reduction rate was much lower in Capitol than in Pollen compared to HN treated plants. Amino acid and protein content was higher in Capitol than in Pollen at bolting stage. They gradually decreased during plant development but not significant between two cultivars and/or two treatments. Glucose, fructose and sucrose content were 1.8-,1.6- or 1.25-fold higher in LN condition than in HN condition, respectively. Amino acid and sucrose content in phloem were largely higher in Capitol than in Pollen under LN condition. These results indicate that the higher seed yield might be related to greater transport ability of amino acid and sucrose in phloem under LN condition.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제16권4호
• /
• pp.1224-1248
• /
• 2022

In various sensor network applications, such as climate observation organizations, sensor nodes need to collect information from time to time and pass it on to the recipient of information through multiple bounces. According to field tests, this information corresponds to most of the energy use of the sensor hub. Decreasing the measurement of information transmission in sensor networks becomes an important issue.Compression sensing (CS) can reduce the amount of information delivered to the network and reduce traffic load. However, the total number of classification of information delivered using pure CS is still enormous. The hybrid technique for utilizing CS was proposed to diminish the quantity of transmissions in sensor networks.Further the energy productivity is a test task for the sensor nodes. However, in previous studies, a clustering approach using hybrid CS for a sensor network and an explanatory model was used to investigate the relationship between beam size and number of transmissions of hybrid CS technology. It uses efficient data integration techniques for large networks, but leads to clone attacks or attacks. Here, a new algorithm called SBEA (Snowball Endurance Algorithm) was proposed and tested with a bow. Thus, you can extend the battery life of your WSN by running effective copy detection. Often, multiple nodes, called observers, are selected to verify the reliability of the nodes within the network. Personal data from the source centre (e.g. personality and geographical data) is provided to the observer at the optional witness stage. The trust and reputation system is used to find the reliability of data aggregation across the cluster head and cluster nodes. It is also possible to obtain a mechanism to perform sleep and standby procedures to improve the life of the sensor node. The sniffers have been implemented to monitor the energy of the sensor nodes periodically in the sink. The proposed algorithm SBEA (Snowball Endurance Algorithm) is a combination of ERCD protocol and a combined mobility and routing algorithm that can identify the cluster head and adjacent cluster head nodes.This algorithm is used to yield the network life time and the performance of the sensor nodes can be increased.

• 한국초지조사료학회지
• /
• 제32권4호
• /
• pp.343-352
• /
• 2012

Sulphur deficiency has become widespread over the past several decades in most of the agricultural area. Oilseed rape (Brassica napus L.) is a very sensitive to S limitation which is becoming reduction of quality and productivity of forage. Few studies have assessed the sulphur mobilization in the source-sink relationship, very little is known about the regulatory mechanism in interaction between sulphur and nitrogen during the short-term sulphur deficiency. In this study, therefore, amount of sulphur and nitrogen incorporated into amino acids and proteins as affected by different S-supplied level (Control: 1 mM ${SO_4}^{2-}$, S-deficiency: 0.1 mM ${SO_4}^{2-}$, and S-deprivation: 0 mM ${SO_4}^{2-}$) were examined. The amount of sulphur in sulphate (S-sulphate) was significantly decreased by 25.8% in S-deprivation condition, compare to control, but not nitrogen in nitrate (N-nitrate). The markedly increase of sulphur and nitrogen incorporated amino acids (S-amino acids and N-amino acids) was observed in both S-deficiency and S-deprivation treatments. The amount of nitrogen incorporated proteins (N-protein) was strongly decreased as sulphur availability while the amount of sulphur incorporated into proteins (S-protein) was not affected. A highly significant ($p{\leq}0.001$) relationship between S-sulphate and S-amino acid was observed whereas the increase of N-amino acids is closely associated with decrease of N-proteins. These data indicate that increase of sulphur and nitrogen incorporated into amino acids was from different nitrogen and sulphur metabolites, respectively

• 한국실내디자인학회논문집
• /
• 제21권1호
• /
• pp.258-268
• /
• 2012

The bathroom is a space where humans fulfil certain daily needs, but for the disabled, it can be the most difficult space to use and may even be a cause of accidents and a source of danger. Previous studies on the bathroom have mostly proposed an ideal model of bathroom, but the majority of disabled people live in small homes of about $50m^2$ in size. As their bathrooms are usually very small, and existing houses have various structural limitations, more research should be conducted on the remodeling of residential bathrooms. This study analyzed a number of remodeling items in bathrooms, all of which were listed in previous studies. Based on 17 cases of residential bathroom remodeling in the homes of disabled people residing in Incheon in 2009, this study analyzed several remodeling items required according to the subject's characteristics, such as a lifestyle, gender, and family composition; and proposed the following remodeling requirements and improvement measures for ambulatory-disabled persons and sedentary-disabled people. First, as ambulatory-disabled people have lower-limb impairments, they required bathroom remodeling designed to improve their mobility in the bathroom. These subjects desired the installation of grab bars, as well as the elimination of floor level differences, the installation of non-slip flooring, a counter-top, a sink stand, and a shower holder whose height can be adjusted. Second, sedentary-disabled people move around in a sitting or crawling position, so many of them asked to eliminate floor level differences and vertically-installed bathroom furnishings. Basically, both people with ambulatory disabilities and people with non-ambulatory impairments requested the elimination of floor level differences and the installation of non-slip flooring and grab bars for the toilet and bathtub. They also asked for the heights of sinks, faucets, mirrors, shower holders, and cabinets to be adjusted to suit their needs.

• 토지주택연구
• /
• 제9권4호
• /
• pp.25-32
• /
• 2018

Application of geothermal energy in buildings has been gaining popularity as it provides the benefits of both heating and cooling a building. Among the various types of geothermal energy systems, ground-coupled heat pump system is the most commonly applied one in South Korea. A ground heat exchanger plays an important role as a heat source in winter and a heat sink in summer. For the stable operation of a ground-coupled heat pump system, a ground heat exchanger should be sized so that it provides sufficient heating and cooling energy. Heating and cooling energies generated in ground heat exchangers mainly depend on the temperature difference between the heating medium in ground heat exchangers and the surrounding ground. In addition, the performance of ground heat exchangers influences the change in ground temperature. Therefore, it is necessary to consider this interrelation between the change in the ground temperature and the performance of ground heat exchanger for an accurate estimation of its performance. However, previous thermal analysis models for ground heat exchangers are not competent enough to allow a complete understanding of this interrelation. Therefore, this study proposes a three-dimensional equivalent, transient ground heat exchanger analysis model. First, a previous thermal analysis model for ground heat exchangers, including an analytical model, a g-function, and a numerical model are analyzed. Next, to overcome the limitations of the previous models, a three-dimensional equivalent, transient ground heat exchanger model is proposed. Finally, this study validated the proposed model with the measurement data of the thermal response test, sandbox test, and TRNSYS DST model. All validation results showed a good agreement. These findings helped us to investigate the thermal performance of ground heat exchangers more accurately than the analytical models, and faster than the numerical models. Furthermore, the proposed model contributes to the design of ground heat exchangers by considering the different operation conditions of buildings.

• 한국지열·수열에너지학회논문집
• /
• 제5권1호
• /
• pp.1-6
• /
• 2009

In this study, an ORC (Organic Rankine Cycle) is investigated for a low-temperature geothermal power generation by a simulation method. A steady-state simulation model is developed to analyze cycle's performance. The model contains a turbine, a pump, an expansion valve and heat exchangers. The turbine and pump are modelled by an isentropic efficiency. Simulations were carried out for the given heat source and sink inlet temperatures, and given flow rate that is based on the typical power plant thermal-capacitance-rate ratio. HFC-245fa is considered as a working fluid of the cycle. Simulation results, at the given secondary working fluids conditions, show that even though the power can be presented by both the evaporating temperature and the turbine inlet superheat, it depends on the evaporating temperature primarily.