Carbon black is a material in the form of fine black powder obtained by incomplete combustion or pyrolysis of hydrocarbons, and is composed of 90-99% carbon, and the rest is composed of hydrogen and oxygen. In the event of an emergency during the manufacture of carbon black, the generated tail gas should be safely discharged through an emergency line to prevent fire, explosion, and environmental pollution accidents caused by the tail gas. If the pressure continues to rise, the pressure control valve shall operate and the rupture plate shall be ruptured sequentially and the tail gas shall be discharged to the vent stack through the emergency line. As an emergency emission system, even if some untreated substances in the tail gas are released into the atmosphere, they are lighter than air, so it is safe to discharge them to a safe place through the Vent Stack. If the gas pressure is rising or worse, it is discharged from the Vent Stackine, and discharging fuel.
음식물류폐기물 직매립, 해양투기 등이 금지됨에 따라 음식물류폐기물은 대부분 자원화를 통해 처리되며 퇴비화하여 생산한 음식물류혼합퇴비(이 하, 음폐퇴비)는 작물 생산성을 향상 등을 위하여 농경지에 퇴비로 사용한다. 하지만, 염분 집적에 의한 작물 생육이 우려되며 이에 따른 피해를 줄이기 위하여 음폐퇴비와 블랙카본, 유용 미생물을 함께 사용하면 염분에 의한 피해를 줄일 수 있을 것으로 기대된다. 이에 본 연구는 음폐퇴비와 바이오차의 한 종류인 블랙카본, 유용 미생물을 처리 시 상추의 수량과 토양 특성 변화를 알아보고자 하였다. 처리구는 무비구(NF), 무기질 비료 (NPK), 무기질 비료 + 음폐퇴비 (NPKF, 대조구), 무기질 비료 + 음폐퇴비 + 블랙 카본 (NPKFC), 무기질 비료 + 음폐퇴비 + 미생물 (NPKFB), 무기질 비료 + 음폐퇴비 + 블랙카본 + 미생물 (NPKFCB)이다. 상추 생육 조사 결과, 생육 후기인 21일째에 NPKFCB 처리구에서 엽장 20.7 cm, 엽폭 20.2 cm, SPAD-502 32.0으로 가장 생육이 좋았으며, 수량 조사 결과 또한 NPKFCB 처리구에서 주당 총 엽수가 28.8개로 가장 많았다. 수량지수는 무처리가 84.1로 가장 낮았고 NPKFCB 처리구에서 128.7로 가장 높았다. 이는 블랙카본에서 공급되는 K, P, Ca 등의 양분과 미생물 활성화가 작물 생산성 향상에 도움을 준 것으로 판단된다. 토양 화학성 분석 결과 pH는 NPKFB 처리구에서 6.9로 가장 높았으며, EC는 NPKF에서 1.7 dS m-1로 가장 높았다.
Black carbon (BC), which is mainly contained in fine particulate matters, is one of the typical anthropogenic air pollutants that are generated from the incomplete combustion process and discharged into the atmosphere, and its various health effects particularly on children have been a growing concern. In this study, BC and particulate matters were closely analyzed in an elementary school adjacent to a high- traffic road in a large metropolitan city. The investigation showed that black carbon behaved similarly to ultrafine dust of 0.3 μm or less in the air, accounting for 20%-40% of it. The occurrence of high concentration outdoor pollution influences the BC content in indoor particulate matters. The average I/O value was 0.7 during the class-hours, and 0.8 without students. However, when students played in the classroom, the range of BC concentrations varied from 0.25 to 1.15, wider than 0.41-1.13 without students. Although this study was conducted with regard to just one elementary school, it can be considered to represent the typical air quality status of domestic schools, and it is believed to present valuable data which can be utilized to assist with preparing measures to enhance the air quality management of schools.
PURPOSES : Graphene nanoplates, which have recently been in the spotlight in various fields, are a layer of graphite used in pencil leads, with carbon arranged in hexagonal honeycomb shapes. The graphene is 0.2 nanometers thick, and it possesses high physical and chemical stability, high strength, and conductivity. These graphene nanoplates have been studied for application in various devices such as semiconductors and batteries, and in the construction sector, where they are used as additives to improve the durability of cement concrete. The purpose of this study was to investigate the physical, and functional properties of graphene-modified asphalt mixtures. METHODS : In this study, the graphene input content of asphalt mixture samples was determined using an asphalt performance grade (PG) test. Based on the results of the test, their strength, stiffness, thermal properties, and electrical conductivity were evaluated. Indirect tensile strength test and dynamic modulus (DM) test were conducted to evaluate the strength and stiffness, and thermal conductivity tests and electrical conductivity evaluations were conducted for determining the functionality of the graphene-modified asphalt mixtures. The thermal conduction test was used to measure the external temperature change over time by placing a general heated asphalt mixture and graphene-modified asphalt with the same raw material-specific mixing ratio inside the temperature chamber in order to measure the heat conductivity. The electrical conductivity was evaluated using a digital multimeter to measure the resistance of DC voltage and DC current via a 4-probe method. RESULTS : The performance grade (PG) test results showed that, for a dynamic shear rheometer (DSR), both tests met the baseline and that physical changes in the binder did not appear evident with graphene addition. Furthermore, each content met the baseline for the bending beam rheometer (BBR). The increasing ratio of flexural creep stiffness approached the maximum when 7.5% graphene was used. In indirect tensile strength test, an average of thrice the indirect tensile strength for graphene-modified asphalt was 0.92 N/mm2, which was approximately 0.04 N/mm2 higher than the average measured three times that of hot mix asphalt mixture, with the same raw material mixing ratio. In the thermal conduction tests, the temperature and the rate of change of temperature of the graphene-modified asphalt mixture were higher than those of the hot-mix asphalt mixture. Lastly, the results of the electric conductivity test using the 4-probe method showed that the electrical conductivity increased slightly as the graphene content increased, but overall, it showed very low electrical conductivity. CONCLUSIONS : In this study, the potential for enhancing the physical and functional performance of graphene nanoplates applied to asphalt mixtures was demonstrated. However, it is practically difficult to arrange graphene particles continuously within an asphalt mixture, which is believed to have very low electrical conductivity.
Conductive polymer composites with high electrical and mechanical properties are in demand for bipolar plates of phosphoric acid fuel cells (PAFC). In this study, composites based on natural graphite/fluorinated ethylene propylene (FEP) and different ratios of carbon black are mixed and hot formed into bars. The overall content of natural graphite is replaced by carbon black (0.2 wt% to 3.0 wt%). It is found that the addition of carbon black reduces electrical resistivity and density. The density of composite materials added with carbon black 3.0 wt% is 2.168 g/cm3, which is 0.017 g/cm3 less than that of non-additive composites. In-plane electrical resistivity is 7.68 μΩm and through-plane electrical resistivity is 27.66 μΩm. Compared with non-additive composites, in-plane electrical resistivity decreases by 95.7 % and through-plane decreases by 95.9 %. Also, the bending strength is about 30 % improved when carbon black is added at 2.0 wt% compared to non-additive cases. The decrease of electrical resistivity of composites is estimated to stem from the carbon black, which is a conductive material located between melted FEP and acts a path for electrons; the increasing mechanical properties are estimated to result from carbon black filling up pores in the composites.
본 연구에서는 polypropylene glycol(PPG) 을 이용한 수분산 폴리우레탄에 카제인을 그래프트 합성한 다음 카본블랙을 분산하여 발생하는 변화를 분석하였다. 이를 위해 카제인을 그래프트한 수분산 폴리우레탄 (PUD와 CPUD’s) 시료를 준비한뒤 카본블랙이 분산된 CPCB’s 시료를 준비하였다. 준비된 시료를 이용하여 인장강도를 측정 한 결과 카제인이 높게 함유된 CPUD3 가 3.01 kgf/㎟ 로 인장강도가 증가하였으며, CPCB’s 에서는 카본 블랙이 증가할수록 인장강도가 2.54 kgf/㎟ 로 낮게 측정되었다. 연신율은 카제인이 적게 함유된 PUD 시료가 278 % 로 측정되었으며, CPCB’s에서는 CP3CB4 가 157% 로 측정되었다. 내마모성은 CPUD3 시료가 36.97 mg.loss, CP3CB4가 41.11 mg.loss 로 표면 강도가 측정되었다. 내용제성은 PUD’s 시료와 CPCB’s 시료 양쪽 모두 물성변화가 없음을 확인 할 수 있었다.
It is known that air pollutants such as fine dust and exhaust gas from vehicles are harmful to human health. In particular, the black carbon emitted by vehicles is known to cause a large number of premature deaths. This study analyzed the effect of a noise barrier on the inflow amount of black carbon from a nearby high traffic road to a school area, using numerical analysis performed at two elementary schools. Also, the correlation between the noise barrier’s shape, height and the inflow amount of black carbon was assessed. As a result, it was found that the higher the noise barrier, the lower the inflow amount of black carbon observed at the school A. However, the inflow amount of black carbon at school B was not greatly influenced by the height of the noise barrier. The inflow amount of black carbon at the schools could be changed not only by the height of the noise barrier, but also by the shape, height and position of the noise barrier and the school building.
Carbon composites for flexible fiber heating element were examined to improve the electrical conductivity in this study. Carbon composites using carbon black, denka black, super-c, super-p with/without CNF or dispersant such as BCS03 and Sikament-nn were prepared. Carbon composite slurry was coated on plane film and yarns(cotton, polyester) and the performances of prepared heating materials were investigated by checking electrical surface resistance, adhesion strength. The plane heating element using carbon black under natural drying condition(25℃) had better physical properties such as surface resistance(185.3 Ohm/sq) and adhesion strength(above 90%) than those of other carbon composite heating elements. From these results, polyester heating element coated by carbon black showed better electrical line resistance(33.2 kOhm/cm) than cotton heating element. Then, it was found that polyester heating element coated by carbon black with CNF(3 wt%) and BCS03(1 wt%) appeared best properties(0.604 kOhm/cm).
Nano-sized β-SiC nanoparticles were synthesized combined with a sol-gel process and a carbothermal process. TEOS and carbon black were used as starting materials for the silicon source and carbon source, respectively. SiO2 nanoparticles were synthesized using a sol-gel technique (Stober process) combined with hydrolysis and condensation. The size of the particles could be controlled by manipulating the relative rates of the hydrolysis and condensation reactions of tetraethyl orthosilicate (TEOS) within the micro-emulsion. The average particle size and morphology of synthesized silicon dioxide was about 100nm and spherical, respectively. The average particles size and morphology of the used carbon black powders was about 20nm and spherical, respectively. The molar ratio of silicon dioxide and carbon black was fixed to 1:3 in the preparation of each combination. SiO2 and carbon black powders were mixed in ethanol and ball-milled for 12 h. After mixing, the slurries were dried at 80˚C in an oven. The dried powder mixtures were placed in alumina crucibles and synthesized in a tube furnace at 1400~1500˚C for 4 h with a heating rate of 10˚C/min under flowing Ar gas (160 cc/min) and furnace cooling down to room temperature. SiC nanoparticles were characterized by XRD, TEM, and SAED. The XRD results showed that high purity beta silicon carbide with excellent crystallinity was synthesized. TEM revealed that the powders are spherical shape nanoparticles with diameters ranging from 15 to 30 nm with a narrow distribution.
금속 주조시 사용되는 탄소이형제를 카본블랙과 점증제 겸 알데하이드 화합물의 경화제로 사용될 수 있는 수용성 고분자인 잔탄검(X-gum), 카르복시메틸셀룰로오스(CMC)을 혼합하여 제조하였다. 이 때 카본블랙의 안정한 분산을 위하여 0.25 wt%의 X-gum 또는 1.0 wt%의 CMC가 적당하였다. 1.0 wt% 보다 낮은 농도의 CMC를 사용했을 경우 카본블랙이 매우 쉽게 층분리되었다. 유리판에 대한 부착력은 경화제와, 구르탈알데하이드 및 사슬연장제인 올리고당의 양에 비례하였으며. X-gum으로 제조된 탄소 이형제는 CMC를 이용해 제조된 것보다 유리에 대한 부착력이 우수하였다. 결과적으로 본 실험의 최적 조건에서 제조된 탄소이형제는 친환경적으로 주조시에 적용할 수 있을 것으로 판단된다.
Composites of insulating polyethylene and carbon black are widely used in switching elements, conductive paint, and other applications due to the large gap of resistance value. This research addresses the critical exponent of dielectric breakdown strength of polymer matrix composites (PMC) made with carbon black and polyethylene below the percolation threshold (Pt) for the first time. Here, Pt means the volume fraction of carbon black of which the resistance of the PMC is transferred from its sharp decrease to gradual decrease in accordance with the increase of carbon-black-filled content. First, the Pt is determined based on the critical exponents of resistivity and relative permittivity. Although huge cohesive bodies of carbon black are formed in case of being less than the Pt, a percolation path connecting the conducting phases is not formed. The dielectric breakdown strength (Dbs) of the PMC below Pt is measured by using an impulse voltage in the range from 10 kV to 40 kV to avoid the effect of joule heating. Although the observed Dbs data seems to be well fitted to a straight line with a slope of 0.9 on a double logarithm of (Pt-VCB) and Dbs, the least squares method gives a slope of 0.97 for the PMC. It has been found that finite carbon-black clusters play an important role in dielectric breakdown.
It is known that the relative dielectric constant of insulating polyethylene matrix composites with conducting materials (such as carbon black and metal powder) increases as the conducting material content increases below the percolation threshold. Below the percolation threshold, dielectric properties show an ohmic behavior and their value is almost the same as that of the matrix. The change is very small, but its origin is not clear. In this paper, the dielectric properties of carbon black-filled polyethylene matrix composites are studied based on the effect medium approximation theory. Although there is a significant amount of literature on the calculation based on the theory of changing the parameters, an overall discussion taking into account the theory is required in order to explain the dielectric properties of the composites. Changes of dielectric properties and the temperature dependence of dielectric properties of the composites made of carbon particle and polyethylene below the percolation threshold for the volume fraction of carbon black have been discussed based on the theory. Above the percolation threshold, the composites are satisfied with the universal law of conductivity, whereas below the percolation threshold, they give the critical exponent of s = 1 for dielectric constant. The rate at which the percentages of both the dielectric constant and the dielectric loss factor for temperature increases with more volume fraction below the percolation threshold.
As a pore precursor, carbon black with different content of 0 to 60 vol% were added to (Ba,Sr) powder. Porous (Ba,Sr) ceramics were prepared by pressureless sintering at for 1h under air. Effects of carbon black content on the microstructure and PTCR characteristics of porous (Ba,Sr) ceramics were investigated. The porosity of porous (Ba,Sr) ceramics increased from 6.97% to 18.22% and the grain size slightly decreased from to with increasing carbon black contents. PTCR jump of the (Ba,Sr) ceramics prepared by adding carbon black was more than , and slightly increased with increasing carbon black. The PTCR jump in the (Ba,Sr) ceramics prepared by adding 40 vol% carbon black showed an excellent value of , which was above two times higher than that in (Ba,Sr) ceramics. These results correspond with Heywang model for the explanation of PTCR effect in (Ba,Sr) ceramics. It was considered that carbon black is an effective additive for preparing porous based ceramics. It is believed that newly prepared (Ba,Sr) cermics can be used for PTC thermistor.
In this paper two aspects of the percolation and conductivity of carbon black-filled polyethylene matrix composites will be discussed. Firstly, the percolation behavior, the critical exponent of conductivity of these composites, are discussed based on studying the whole change of resistivity, the relationship between frequency and relative permittivity or ac conductivity. There are two transitions of resistivity for carbon black filling. Below the first transition, resistivity shows an ohmic behavior and its value is almost the same as that of the matrix. Between the first and second transition, the change in resistivity is very sharp, and a non-ohmic electric field dependence of current has been observed. Secondly, the electrical conduction property of the carbon black-filled polyethylene matrix composites below the percolation threshold is discussed with the hopping conduction model. This study investigates the electrical conduction property of the composites below the percolation threshold based on the frequency dependence of conductivity in the range of 20 Hz to 1 MHz. There are two components for the observed ac loss current. One is independent of frequency that becomes prevalent in low frequencies just below the percolation threshold and under a high electrical field. The other is proportional to the frequency of the applied ac voltage in high frequencies and its origin is not clear. These results support the conclusion that the electrical conduction mechanism below the percolation threshold is tunneling.
For development of a human body model for electric shock, electroconductive paints with carbon black as a filler material were developed. The characteristics of the volume resistivities of thin films fabricated using the electroconductive paints were investigated as a function of the particle sizes and content of carbon black. With a carbon black particle size over 80 μm, agglomeration of carbon black powders was observed. The volume resistivity of the particles increased as the porosity increased and as the amount of carbon black decreased due to the agglomeration of carbon black powders. With a particle size of 4 μm and 20 μm, agglomeration of carbon black powders was not observed and their porosities were measured as 0.86% and 1.12% with volume resistivities of 20 Ω·cm and 80 Ω·cm respectively. A carbon black particle size of less than 20 μm is considered to be suitable as a type of electric-shock electroconductive paint for a human body model.
In the present work, the choice of the nano carbon black and optimum mixed ratio and effectiveness of the mixed carbon black to get a raw data for a manufacturing method of conductive complex board. Optimum mixed ratio of paper sludge & water was 1 : 2.5 for reformations. HB-41-Y was cheaper than Super-P with the single carbon black. Also electric conductivity of HB-41-Y(6.406×10-2 Ωcm-1) was about 6.5 times higher than Super-P(9.741×10-3 Ωcm-1) at 20 wt% carbon black. This time optimum mixture ratio of the paper sludge and the carbon black to be about 15 wt%, optimum mixed ratio HB-41Y and Graphite about 3:1 and its electric conductivity was 5.824×10-2 Ωcm-1.