Influence of Energy Density on Energy Demand and Porosity of 316L Stainless Steel Fabricated by Selective Laser Melting

Tao Peng,Chao Chen 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.5 No.1

Selective laser melting (SLM) is one of the most widely used metal additive manufacturing technologies in producing high density parts. Energy density, a key-parameter combination, has been recognized to have a relationship with part formation, but such a relationship is extremely complex. This work aims to investigate energy density as a measure to evaluate energy demand in fabricating pore-free 316L stainless steel SLM parts. Key parameters in energy density were considered in the developed energy demand model. The impact of energy density on the porosity was analyzed with the data from experiments and existing works. Either low or high energy density can result in larger and more pore formation, and the influencing parameter was laser power, followed by layer thickness, scan speed, and hatch space. An effective energy-optimal (E2O) zone was proposed, where a relationship between energy density and porosity was developed. It is suggested that high laser power with high scan speeds can deliver energy to a thicker layer with relatively stable melt pool, fabricating high density parts. Hatch space can be decided accordingly to actual melt pool formation. This combination can effectively reduce energy density, and corresponding energy demand.

Effects of probiotic supplementation in different energy and nutrient density diets on performance, egg quality, excreta microflora, excreta noxious gas emission, and serum cholesterol concentrations in laying hens

Zhang, Z. F.,Kim, I. H. American Society of Animal Science 2013 Journal of Animal Science Vol.91 No.10

<P>This 6-wk study was conducted to determine the effects of probiotic (<I>Enterococcus faecium</I> DSM 7134) supplementation of different energy and nutrient density diets on performance, egg quality, excreta microflora, excreta noxious gas emission, and serum cholesterol concentrations in laying hens. A total of 432 Hy-Line brown layers (40 wk old) were allotted into 4 dietary treatments with 2 levels of probiotic supplementation (0 or 0.01%) and 2 levels of energy (2,700 or 2,800 kcal ME/kg) and nutrient density. Weekly feed intake, egg quality, and daily egg production were determined. Eighteen layers per treatment (2 layers/replication) were bled to determine serum cholesterol concentrations at wk 3 and 6. Excreta microbial shedding of <I>Lactobacillus</I>, <I>Escherichia coli</I>, and <I>Salmonella</I> and noxious gas emission were determined at the end of the experiment. Hens fed the high-energy and high-nutrient-density diets had less (<I>P</I> < 0.01) ADFI than those fed the low-energy and low-nutrient-density diets throughout the experimental period. During wk 4 to 6 and overall, hens fed the diets supplemented with the probiotic had greater (<I>P</I> < 0.01) egg production, egg weight, and eggshell thickness than hens fed the diets without the probiotic. Dietary supplementation of the probiotic increased (<I>P</I> = 0.01) excreta <I>Lactobacillus</I> counts and decreased (<I>P</I> = 0.02) <I>Escherichia coli</I> counts compared with hens fed the diets without the probiotic. The excreta ammonia emission was decreased (<I>P</I> = 0.02) in hens fed the probiotic diets compared with hens fed the diets without the probiotic. Serum total cholesterol concentration was decreased (<I>P</I> < 0.01) by feeding hens with the probiotic at wk 3 and 6. Layers fed the probiotic-incorporated diets had greater (<I>P</I> < 0.01) high-density lipoprotein (HDL) cholesterol and lower (<I>P</I> = 0.03) low-density lipoprotein (LDL) cholesterol concentrations than hens fed the nonsupplemented diets at wk 6. Interactive effects (<I>P</I> < 0.05) of energy and nutrient density and the probiotic on excreta <I>Lactobacillus</I> counts and serum HDL cholesterol concentration were observed at wk 6. In conclusion, dietary supplementation of 0.01% probiotic improved egg production and egg quality and decreased excreta ammonia emission. The use of a probiotic in the high-energy and high-nutrient-density diets may be more favorable than the low-energy and low-nutrient-density diets in laying hens.</P>

Development of a high-energy-density portable/mobile hydrogen energy storage system incorporating an electrolyzer, a metal hydride and a fuel cell

Han, Gwangwoo,Kwon, YongKeun,Kim, Joong Bae,Lee, Sanghun,Bae, Joongmyeon,Cho, EunAe,Lee, Bong Jae,Cho, Sungbaek,Park, Jinwoo Elsevier 2020 APPLIED ENERGY Vol.259 No.-

<P><B>Abstract</B></P> <P>A hydrogen energy storage system for portable/mobile applications such as personal power sources and unmanned underwater vehicles is developed. An application-oriented design and system integration strategy are newly suggested to maximize energy density while incorporating conventional technologies for the electrolyzer (Ely), the metal hydride (MH), and the polymer electrolyte membrane fuel cell (PEMFC). To improve both the energy density and usability, the systems for charging and discharging are separated. The charging component is composed of a water Ely (0.5 Nm<SUP>3</SUP> h<SUP>−1</SUP>) and an MH cooling device as one system. The discharging component consists of an MH (900 NL H<SUB>2</SUB>), a PEMFC stack (50 W), and a power conditioning system (PCS) as a single system. The MH material and engineering properties are investigated to find an MH that is suitable for the target system. The hybrid design and operating strategy of the PEMFC and PCS are developed to maximize energy density. The prototype system provides a nominal power output of 31.5 W at 12 V for 38 h with one recharging. We find it significant that the discharging component shows an energy density of 410 Wh L<SUP>−1</SUP>, which is twice that of conventional energy storage systems at the 2.9-L level.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The core components are a water electrolyzer, a metal hydride, and a PEMFC. </LI> <LI> AB<SUB>5</SUB>- and AB<SUB>2</SUB>-type metal hydrides are investigated as energy storage media. </LI> <LI> The hybrid design and operating strategy of the PEMFC and PCS are developed. </LI> <LI> A 2.9-L H<SUB>2</SUB> energy storage system with a 410 Wh L<SUP>−1</SUP> energy density is developed. </LI> <LI> The system provides 1200 Wh of electricity with a nominal power of 31.5 W at 12 V. </LI> </UL> </P>

Ideal nanoporous gold based supercapacitors with theoretical capacitance and high energy/power density

Kim, Sun-I,Kim, Sung-Wook,Jung, Kyoungok,Kim, Jin-Baek,Jang, Ji-Hyun Elsevier 2016 Nano energy Vol.24 No.-

<P><B>Abstract</B></P> <P>Supercapacitors are known to suffer from relatively low energy density and stability, which hampers their substitution for existing batteries. Here, we report an outstanding positive electrode platform for supercapacitor having both high energy density and high power density as well as good stability, by fabricating a low resistance Ohmic contact between Ni(OH)<SUB>2</SUB> active materials and a 3-D current collector, nanoporous gold (NPG). The Ni(OH)<SUB>2</SUB>/NPG electrode was optimized by finely adjusting the portion of two different parts of the deposited Ni(OH)<SUB>2</SUB>, one part in direct contact with the NPG and the other part on top of the NPG. The optimized Ni(OH)<SUB>2</SUB>/NPG electrode exhibited 2223F/cm<SUP>3</SUP> of volumetric capacitance (considering both the active material and the current collector) at a current density of 5A/g, values which are beyond the theoretical capacitance value, and the device retained 90% capacitance of the initial value at 500A/g and after 30,000 cycles, respectively. This electrode showed an excellent energy density of 98Wh/kg and power density of 50kW/kg in a Ni(OH)<SUB>2</SUB>/NPG//MnO<SUB>2</SUB>/NPG two electrode supercapacitor system. The excellent performance of the Ni(OH)<SUB>2</SUB>/NPG electrode is attributed not only to the increased surface area of the Ni(OH)<SUB>2</SUB> active materials, but also to the favorable path for charge transport created between the Ni(OH)<SUB>2</SUB> and the gold electrode due to the presence of Ohmic contact, which eventually leads to the good kinetic properties and good stability.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ni(OH)<SUB>2</SUB>/NPG electrode showed the high capacitance, high energy density, and semi-permanent lifetime. </LI> <LI> The optimized capacitance values reached 3168 F/g and 2223 F/cm<SUP>3</SUP>, which retained at high current density and after 30,000 cycles. </LI> <LI> The electrode showed an excellent energy density of 98 Wh/kg and power density of 50 kW/kg. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

INTERACTION EFFECT BETWEEN BEAM DIAMETER AND ENERGY DENSITY IN LASER-INDUCED TACTILE PERCEPTION

CHOI, MI-HYUN,KIM, HYUNG-SIK,JO, JI-HUN,KIM, JI-SUN,JUN, JAE-HOON,PARK, JONG-RAK,CHUNG, SOON-CHEOL World Scientific Publishing Company 2018 JOURNAL OF MECHANICS IN MEDICINE AND BIOLOGY Vol.18 No.7

<P>This study aims to investigate the interaction effect between the beam diameter and energy density, which are perceived as laser-induced tactile perception by humans, by diversely varying the laser parameters, beam diameter, and energy. Eight healthy male college students of 23.5<TEX>$ \,$</TEX><TEX>$ \pm $</TEX><TEX>$ \,$</TEX>1.7 years participated in the study. The range of the beam diameter of the displayed laser stimulation was between 0.03<TEX>$ \,$</TEX>mm and 8<TEX>$ \,$</TEX>mm, and a total of 21 sizes were displayed. The laser energy was sequentially displayed from the minimum energy that can be displayed by one beam diameter to the maximum energy range that does not exceed the maximum permissible exposure (MPE) level since the energy varies according to the beam diameter. The laser energy was controlled by an optical density (<TEX>$ \text{OD}=0.4$</TEX>) filter and was measured by an optical power meter (energy meter). Furthermore, the beam diameter was adjusted by moving the lens, which was confirmed with the beam profiler. The experimental test consists of the control phase (19<TEX>$ \,$</TEX>s), stimulus phase (7<TEX>$ \,$</TEX>s), and response phase (4<TEX>$ \,$</TEX>s); the total duration of the test was 30<TEX>$ \,$</TEX>s. The stimulus phase is the period in which stimulation was displayed on the skin through laser irradiation, and the stimulation was displayed by changing the beam diameter and the energy from the laser. The total number of beam diameter and energy pairs displayed to the subjects was 113 and 5 trials of irradiation were conducted for each pair. Stimulation perception response was recorded by pressing the response buttons during the response phase, and the responses were predefined as “no feeling,” “tactile sensation”, and “pain.” Through the extracted response data from the response phase, the beam diameter and energy density pair in which more than 50% of the subjects responded as having perceived tactile sensation were selected from the possible laser energy that could be displayed from one beam diameter. The simulation results showed that increasing the beam diameter increased the penetration depth, indicating an effective energy transfer to the skin. Therefore, increasing the beam diameter results in increased scattering, and hence increased penetration depth, and ultimately a more effective energy transfer. Therefore, increased beam diameter results in higher energy transfer efficiency, indicating that the required energy density by more than 50% of the subjects to perceive tactile sensation decreased.</P>

토종 실용계의 사육밀도 및 사료 내 에너지 수준에 따른 생산성, 혈액, 면역 및 계육 품질에 미치는 영향

김광열(KwangYeol Kim),전진주(Jin-Joo Jeon),김현수(Hyunsoo Kim),손지선(Jiseon Son),김희진(Hee-Jin Kim),유아선(Are-Sun You),홍의철(Eui-Chul Hong),강보석(Boseok Kang),강환구(Hwan Ku Kang) 한국가금학회 2021 韓國家禽學會誌 Vol.48 No.2

본 연구는 토종 실용계 사육 시 사육밀도와 에너지 함량에 따른 생산성, 혈액 성분, 면역 및 계육품질에 미치는 영향에 대해 구명하고자 수행되었다. 토종닭 병아리 240수를 공시하여 4처리 4반복 반복당 15수씩 완전 임의 배치하였다. 처리구는 사육밀도 2 수준(14, 16 birds/m2)과 에너지 2 수준 [ME kcal/kg; High: starter(3,150), grower(3,200), Final(3,250); Low: starter(2,950), grower(3,000), Final(3,050)]으로 2 × 2 요인실험 설계하였다. 체중분석 결과 SD 14 처리구와 EL High 처리구에서 유의적으로 높은 것으로 나타났다. 증체량에서는 초기와 후기에서 에너지 함량에 따라 EL High 처리구가 유의적으로 높게 나타났으며, 전구간에서는 사육밀도와 에너지 함량에 따라 SD 14 처리구와 EL High 처리구가 유의적으로 높게 나타났다. 사료섭취량은 초기, 중기와 전구간에서 사육밀도에 따라 SD 14 처리구가 유의적으로 높게 나타났다. 사료 요구율은 에너지 함량에 따라 EL High 처리구가 유의적으로 낮게 나타났다. 혈액 내 생화학 조성 결과 AST에서는 사육밀도에 따라 SD 16 처리구가 높게 나타났다. 면역글로블린과 코티솔 분석결과 IgM에서 사육밀도 × 에너지 함량에 따라 유의적인 차이가 나타났으나, 코티솔에서는 유의적인 차이는 나타나지 않았다. 결론적으로 사육밀도가 높을수록 섭취경쟁으로 인하여 AST가 증가하였고, 이로 인해 생산성이 감소되었다. 그리고 에너지 함량이 높을수록 생산성이 개선되었다. 그러나 혈액, 면역 및 계육 품질의 결과는 일정하지 않았으며, 좀 더 자세한 연구가 필요할 것으로 보인다. The study determined the effects of stock density (SD) and energy level (EL) on growth performance, serum biochemistry, and meat quality in Korean native chickens. A total of 240 chickens were randomly assigned to one of the four treatments including two stock density (low, 14, and high, 16 chickens per m²) and two energy level (low, 2,950, 3,000, 3050 ME kcal/kg, and high 3,150, 3,200, 3,250 ME kcal/kg, for starter, grower, and finisher, respectively). During the whole period of the experiment, the chickens were fed ad libitum. The greater final body weight and weight gain were achieved in chickens fed high energy diet, whereas the final body weight and weight gain were significantly reduced in high-density treatment compared with the low density. Chickens in low-density groups had a higher feed intake compared with high-density treatment, however, the energy level did not affect the feed intake. An improved overall feed conversion ratio was detected in the high energy treatment. There was a significant interaction between stock density and energy level on cholesterol concentration. The concentration of aspartate transaminase in serum was increased by higher stock density. There was a significant treatment interaction on IgM levels. Moreover, the carcass rate was significantly increased in the high energy level treatment. Based on the findings, we suggest that rearing chickens in low density with high dietary energy levels could be beneficial by improving the growth performance.

Energy Enhancement Using an Upward Density Ramp in Laser Wakefield Acceleration

김재훈,김근주,유승훈 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.51

The effect of the plasma density ramp structure on the electron energy in the laser wakefield acceleration was studied. The plasma wavelength and the acceleration field strength are changed along the laser propagation direction with density ramp structure. With downward density ramp the electron energy decreases due to the lag of the acceleration region and lower acceleration field strength than with uniform density but with the upward ramp the energy increases because of the higher acceleration field and the position of the acceleration region. These effects are studied by simulations using 2-dimensional particle in cell code and by the experiments using a 20 TW laser. The simulation results show that in the case of the upward density ramp the acceleration region moves faster than in the uniform case and the plasma wave generates higher acceleration field. These effects increase the electron energy. The energy measurement experiments conducted using 20 TW laser system show that the electron energy with upward density ramp is higher than the energy with uniform density.

A new approach to high-performance flexible supercapacitors: Mesoporous three-dimensional Ni-electrodes

Kim, Sun-I.,Kang, Ji-Hun,Kim, Sung-Wook,Jang, Ji-Hyun Elsevier 2017 Nano energy Vol.39 No.-

<P><B>Abstract</B></P> <P>The demand for portable electronic devices is driving the development of flexible supercapacitor, while current devices still need to improve the performance for practical applications. Here, we report a cost-efficient flexible three-dimensional-Ni (3D-Ni) electrode for a flexible supercapacitor with excellent energy density and power density. The meso-porous 3D-Ni electrode provides a large number of active sites to store charges and good accessibility to the ions in polymer electrolytes, leading to excellent capacitance, high energy density, as well as high power density. The Ni(OH)<SUB>2</SUB>/3D-Ni positive electrode showed an outstanding specific capacitance of ~3400F/g at 10A/g and retained 80% of the initial capacitance at 200A/g. The negative MnO<SUB>2</SUB>/3D-Ni electrode exhibited a specific capacitance of 1250F/g at 10A/g and excellent capacitance retention of 82% at 200A/g. The Ni(OH)<SUB>2</SUB>/3D-Ni//MnO<SUB>2</SUB>/3D-Ni hybrid supercapacitor delivered an excellent energy density of 75Wh/kg and a high power density of 5.3kW/kg, and these values did not change under bending conditions. The 3D-Ni electrode introduced here represents a new type of ideal electrode that can be easily applied to various flexible/wearable electronic device with excellent performance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The flexible solid-state supercapacitor delivered an outstanding specific capacitance of ~3400F/g at 10A/g, an excellent energy density of 75Wh/kg, and a high power density of 5.3kW/kg. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The highly meso-porous 3D-Ni electrode provides a large number of active sites to store charges and provide good accessibility to the ions in electrolytes, leading to excellent electrochemical performance. The Ni(OH)2/3D-Ni electrode showed an outstanding specific capacitance of ~3400F/g at 10A/g and retained 80% of the initial capacitance at 200A/g. The flexible hybrid supercapacitor delivered an excellent energy density of 75Wh/kg and a high power density of 5.3kW/kg.</P> <P>[DISPLAY OMISSION]</P>

High Volumetric Energy Density Hybrid Supercapacitors Based on Reduced Graphene Oxide Scrolls

Rani, Janardhanan R.,Thangavel, Ranjith,Oh, Se-I,Woo, Jeong Min,Chandra Das, Nayan,Kim, So-Yeon,Lee, Yun-Sung,Jang, Jae-Hyung American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.27

<P>The low volumetric energy density of reduced graphene oxide (rGO)-based electrodes limits its application in commercial electrochemical energy storage devices that require high-performance energy storage capacities. in small volumes. The volumetric energy density of rGO-based electrode materials is very low due to their low packing density. A supercapacitor with enhanced packing density and high volumetric energy density is fabricated using doped rGO scrolls (GFNSs) as the electrode material. The restacking of rGO sheets is successfully controlled through synthesizing the doped scroll structures while increasing the packing density. The fabricated cell exhibits an ultrahigh volumetric energy density of 49.66 Wh/L with excellent cycling stability (>10000 cycles). This unique design strategy for the electrode material has significant potential for the future super capacitors with high volumetric energy densities.</P>

Non-flammable organic liquid electrolyte for high-safety and high-energy density Li-ion batteries

Pham, Hieu Quang,Lee, Hee-Yeol,Hwang, Eui-Hyung,Kwon, Young-Gil,Song, Seung-Wan Elsevier 2018 Journal of Power Sources Vol.404 No.-

<P><B>Abstract</B></P> <P>With increased energy density of rechargeable lithium-ion batteries for powering smart phones and electric vehicles and for their long range use, battery safety becomes more important than ever. This aspect motivated us to develop non-flammable liquid electrolyte that removes the risk of battery fire and explosion, which is urgently needed. Battery energy density and performance however should not be sacrificed to achieve just the safety. Here we report for the first time a rational design of non-flammable carbonate-based organic liquid electrolyte to satisfy safety, energy density and performance simultaneously. Our novel electrolyte, composed of 1 M lithium hexafluorophosphate salt and propylene carbonate and fluorinated linear carbonate co-solvents, at unmeasurable flash point does not fire representing non-flammable safe batteries but permits high-voltage stability to enable high-voltage charge of lithium-rich layered oxide cathode up to 5.0 V, high-energy density of 856 Wh per kg of cathode active mass and stable charge-discharge cycling performance of full-cell with graphite anode, in contrast to rapid performance fade of flammable conventional electrolyte system. The discovery of non-flammable carbonate-based organic liquid electrolyte opens up a new avenue to high-safety and high energy-density lithium-ion batteries for electric vehicles and advanced energy-storage applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Rational design of non-flammable carbonate-based organic liquid electrolyte. </LI> <LI> High energy density of non-flammable full-cell with Li-rich layered oxide cathode. </LI> <LI> Preserved cathode structure and stable interface with non-flammable electrolyte. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>