• Korean Journal of Agricultural Science
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• v.12 no.1
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• pp.101-107
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• 1985

Since most farmers breeding livestocks in Korea is depended on imported feeds, the rate of self-supplying feeds is very important for a stable development of farmers. Therefore, it is considered necessary to increase the rate of self-supplying feeds. In this study, performance tests were carried out with barley and forage to find the design's parameters of hammer for a small size hammer mill which can be driven by 3.7-7.5 kW power tiller being used by most farmers. The revolution speed of hammer mill was 3000 rpm, widths of hammer were 20mm, 30mm, 40mm, and the levels of thickness of hammer were 2mm, 4mm and 6mm. Experimental materials used were barley and forage and screen openings for barley was 4.76mm, and 3.18mm for forage. The study results can be summarized as follows; 1. Results of grinding tests showed that particle sizes were 478-774 microns for barley and 350-434 microns for forage. They were decreased according to the increasing thickness and width of hammer. 2. Fineness modulus of grinded materials were 3.07-3.62 for barley and 2.69-2.93 for forage. They were inversely proportional to thickness and width of hammer. 3. The required power for grinding was 3.8-5.0 kW for barley and 0.9-1.4 kW for forage. The thickness of hammer was more important for less power requirement than width of hammer. 4. Grinding performance of a small size hammer mill was 99-170kg/kWh for barley and 11-21 kg/kWh for forage. The thickness of hammer was an important factor for grinding performance, and inversely proportional to grinding performance. For about 3.2 of fineness modulus, 4 mm thickness was the best, and an optimum width of hammer was 30mm for a small size hammer mill.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.73-77
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• 2001

In this paper, we propose a virtual action system based on information agents, We call the system the MultiHammer, MultiHammer can be used for studying and analyzing online actions. MuiltiHammer provides functions of implement-ing a meta online action site and an experiment environ-ment. We have been using MultiHammer as an experiment as an experiment environment for BiddinBot. BiddingBot aims at assisting users to bid simultaneously in multiple online auctions. In order to bid simultaneously in multiple online auctions. In order to analyze the behavior of BiddngBot, we need to pur-chase a lot of items. It is hard for us to prepare a lot of fund to show usability and advantage of BiddingBot. MultiHam-mer enables us to effectively analyze the behavior of BiddingBot. MultiHammer consists of three types of agents for information collecting data storing and auctioning. Agents for information wrappers. To make agent work as wrarp-pers, we heed to realize software modules for each online action site. Implementing these modules reguires a lot of time and patience. To address this problem, we designed a support mechanism for developing the modules. Agents for data storing record the data gathered by agents for informa-tion collecting. Agents for auctioning provide online services using data recorded by agents for data storing. By recording the activities in auction sites. MultiHammer can recreate any situation and trace auction for experimentation, Users can participate in virtual using the same information in real online auctions. Users also participate in real auc-tions via wrapper agents for information collecting

• Journal of the Korea Concrete Institute
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• v.17 no.3 s.87
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• pp.313-322
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• 2005

Recently, as the remodeling market gradually substitute for new construction market and safety diagnosis for reconstruction apartment become a matter of principal Interest, it is demanded that scientific diagnosis and evaluation for existing concrete structure state. And it is increasing that the significance for reliability of data which is used for estimating the concrete compressive strength by nondestructive test. As a result, it is found that different proposal to material age and hitting angle is good to improving the reliability of presumption of concrete compressive strength in the linear hitting rebound test hammer. And for the reason that mutual relation between the compressive strength and rebound degree is highest in linear hitting rebound test hammer 25mm in all portion according to early md middle material age and hitting angle except the early material age $-45^{\circ}$, analysis showed that linear hitting rebound test hammer is more reliable than existing schmidt hammer in presumption of concrete compressive strength.

• Journal of the Korean Geotechnical Society
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• v.21 no.9
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• pp.5-12
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• 2005

SPT hammer energy and its delivery are hon to influence the N value. The SPT hammer energy is classified into theoretical energy, velocity energy, rod energy and dynamic efficiency. In this study, the rod energy and the velocity energy are measured directly by PDA and Digital Line-Scan Camera which are most widely used type of SPT apparatus in Korea. The Dynamic efficiency is calculated through measured data. As the results of this study, the averages of rod energy ratio of donut, safety and automatic hammer are measured at 49.57, 61.60, and at $87.04\%$ by FV method. The averages of hammer velocity of donut, safety and automatic hammer are measured at $3.177{\pm}0.872$, $3.385{\pm}0.681$, and at $3.651{\pm}0.550$ m/s by Digital Line-Scan Camera, with the dynamic efficiencies at 0.732, 0.801, and 0.973 respectively.

• Computers and Concrete
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• v.21 no.5
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• pp.525-530
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• 2018

As a nondestructive testing method, the Schmidt rebound hammer is widely used for structural health monitoring. During application, a Schmidt hammer hits the surface of a concrete mass. According to the principle of rebound, concrete strength depends on the hardness of the concrete energy surface. Study aims to identify the main variables affecting the results of Schmidt rebound hammer reading and consequently the results of structural health monitoring of concrete structures using adaptive neuro-fuzzy inference system (ANFIS). The ANFIS process for variable selection was applied for this purpose. This procedure comprises some methods that determine a subsection of the entire set of detailed factors, which present analytical capability. ANFIS was applied to complete a flexible search. Afterward, this method was applied to conclude how the five main factors (namely, age, silica fume, fine aggregate, coarse aggregate, and water) used in designing concrete mixture influence the Schmidt rebound hammer reading and consequently the structural health monitoring accuracy. Results show that water is considered the most significant parameter of the Schmidt rebound hammer reading. The details of this study are discussed thoroughly.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.3
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• pp.363-369
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• 2003

In this study, cell cracker method as a non-collision method was evaluated for the possibility of new red ginseng grinding technique. The moisture contents were 3.16% for the powder pulverized by hammer mill (group A) and 6.30% for the powder produced by cell cracker (group B), and the difference between both groups was significant, The contents of other component such as ash, crude lipid, reducing sugar, total sugar, acidic polysaccharide, crude fiber and crude protein between both groups were not significant. There were no significant differences in phenolic compound, fatty acid, amino acid, free sugar, crude saponin and ginsenosid contents between both groups. And also the contents of mineral components were evaluated to determine the incorporation of red ginseng powder during grinding, and also the differences of those between both groups were not significant.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.6
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• pp.603-611
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• 2016

Research and development of mineral-resource-related products has progressed with the increased need to develop mineral resources. The DTH hammer is a resultant product. However, owing to particular work conditions of underground drilling, it is difficult to obtain direct data on the DTH hammer. A DTH drill rig requires a significant amount of money and time for actual testing. This thesis aimed to resolve this problem by using CAE. In a previous paper, the structure of the DTH hammer and its movement were analyzed, and a standard model based on simulation was proposed. Then, experimentation and comparison verification were conducted. In this paper, by using an experimental design method, we derived a control factor of the impact force and efficiency of the DTH hammer and attempted to optimize the design. As a result, the impact energy increased by 14.9%, and the efficiency increased by 3.3%.

• Geotechnical Engineering
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• v.13 no.1
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• pp.169-182
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• 1997

It is known that some amount of loss in impact energy takes place due to some limitations and problems during the performance of the field SPT. Actual energy level tractsferred to the rod should be measured to correct the SPT-N values tested in the field In this paper, the ratio of energy transferred to the rod through the anvil to impact energy is measured by using sharpy impact test equipment and also analysed by using GRL-WEAP This result is certified and compared with that of field SPT As the results of this study, the average rod energy ratio of the R-P hammer and the Trip hammer is calculated at 0.726 and 0.728 respectively, but it is suggested that 0.72 should be used. By using the hammer energy ratio 64.2% and 75.0% obtained from field measurement, the average energy ratio of the SPT for the R-P hammer is calculated at 46.7% and 54.5% for the Trip hammer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.269-274
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• 2016

This paper proposes the development of a low frequency electronic hammer drive system that is used to prevent scaling or clogging in the hopper process. The electro-mechanical hammering driving method involves the generation of vibration and impact energy. The operation principles of the electromagnetic hammer were considered by parallel/series spring coefficient analysis and the amount of kinetic energy generated was calculated from the product of the equivalent spring constant, which is coupled with the E core and the gap of between the E core and I core. In addition, the Pulsation Driving algorithm was applied to the proposed electromagnetic hammer to obtain the maximizing kinetic energy. This algorithm was then implemented by a logical AND operation process and micro-controller (atmega128) built in functions with a timer interrupt and PWM generation function. The driving circuit of the electromagnetic hammer was designed using the H-bridge type IGBT circuit. The experimental test was performed by usefulness of the developed electromagnetic hammer systems with the acceleration measurement method. The experimental result showed that the proposed system has good kinetic energy generation performance and can be applied to the hopper process.

• Journal of the Korea Institute of Building Construction
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• v.19 no.3
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• pp.229-237
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• 2019

This study examines the estimation of strength through a ultra-high strength concrete mock-up specimen using the rock compressive strength test hammer. According to the test result, the commonly used strength estimation formulae showed differences among them when the data of this test were applied. In additional, it show that these formulae underestimated the actual measurements further when the compressive strength was 30MPa or greater and deviated the distribution range of actual measurements in all strength ranges. The rock test hammer showed a higher correlation than type N Schmidt hammer regardless of the direction of hit for each type of W/B and the inclusion of coarse aggregate, and mortar showed a little higher correlation than concrete. As a result, it can be suggested that the coefficient of variation and the standard deviation of the mortar(2.26%/1.36) are lower than those of the concrete(4.06%/2.5), and the smaller the size of the coarse aggregate, the smaller the coefficient of variation and the more accurate the value.