检索结果-内蒙古大学图书馆

Current studies of heat transfer enhancement on double pipe heat exchanger

AIP Conference Proceedings 2020年第1期2248卷

作者： Mustaza Ma’a Tri Agung Rohmat Samsul Kamal 1Departement of Mechanical and Industrial Engineering Faculty of Engineering Universitas Gadjah Mada Jl. Grafika No 2 Yogyakarta 55281 Indonesia 2Study Program of Mechanical Engineering Departement of Industrial Technology Politeknik Caltex Riau Jl. Umban Sari No1 Pekanbaru – Riau 28265 Indonesia

This paper gives an overview of several published current studies concerning heat transfer enhancement on the double pipe heat exchanger. Since double pipe heat exchanger has drawn much consideration due to simplicity and wide-range utility. The flow manipulation technique to enhance heat transfer in a double pipe heat exchanger has been frequently cited. Also, various research addressing working fluid on a double pipe heat exchanger has been discussed in detail. Another technique is known as surface modification that has an infrequent investigation comparing the other techniques. Correlation of Nusselt number and pressure drop coefficient shown in this overview. Future research opportunities are mentioned.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Performance improvement of palm oil foaming agent concentrates as fire extinguishment materials in peatlands

引用

IOP Conference Series: Earth and Environmental Science 2020年第1期460卷 012026-012026页

作者： M Rivai E Hambali A Suryani G Pramuhadi P Subekti Surfactant and Bioenergy Research Center IPB University Indonesia Department of Agroindustrial Technology IPB University Indonesia Department of Mechanical and Biosystem Engineering IPB University Indonesia Post Graduate Student Study Program of Agroindustrial Technology IPB University Indonesia Department of Mechanical Engineering Pasir Pengaraian University Indonesia

Foaming agent concentrate made from palm oil produced as a fire extinguishing material in peatlands at a laboratory-scale test were able to extinguish a fire within 3.16 to 4.49 hours. Fire extinguishing ability of this foaming agent concentrate resulted in a lower solution use and shorter extinguishing time than water. However, when compared to commercial products, fire extinguishing time was still longer although the amount of solution needed to extinguish the fire was lower. Therefore, it was necessary to improve the formula to produce a foaming agent concentrate that was able to extinguish the fire in a shorter time with a lower amount of fire extinguishing solution. This study aims to improve the performance of palm oil foaming agent concentrate on extinguishing the fire in peatlands. Efforts to improve the performance were made by reformulation and the addition of chemical fire retardants. Results showed that the addition of fire retardant reduced foaming ability, increased surface tension, lowered viscosity, lowered contact angle, and reduced fire extinguishing time to about 13.08-69.21%.

关键词： Improved formulation palm oil foaming agent concentrate fire extinguisher reduction of extinguishing time

来源：评论

学校读者我要写书评

暂无评论

Calcium release and physical properties of modified carbonate apatite cement as pulp capping agent in dental application

引用

Biomaterials Research 2018年第1期22卷 346-351页

作者： Zakaria, Myrna Nurlatifah Cahyanto, Arief El-Ghannam, Ahmed Department of Endodontology and Operative Dentistry Program Study of Dentistry Faculty of Medicine Universitas Jenderal Achmad Yani Cimahi Indonesia Department of Dental Materials Science and Technology Faculty of Dentistry Universitas Padjadjaran Sumedang-Jatinangor Indonesia Department of Mechanical Engineering and Engineering Science The University of North Carolina at Charlotte Charlotte NC United States

Background: Carbonate apatite (CO3Ap) and silica-calcium phosphate composite (SCPC) are bone substitutes with good prospect for dental application. SCPC creates a hydroxyapatite surface layer and stimulate bone cell f... 详细信息

Background: Carbonate apatite (CO₃Ap) and silica-calcium phosphate composite (SCPC) are bone substitutes with good prospect for dental application. SCPC creates a hydroxyapatite surface layer and stimulate bone cell function while, CO₃Ap induce apatite crystal formation with good adaptation providing good seal between cement and the bone. Together, these materials will add favorable properties as a pulp capping material to stimulate mineral barrier and maintain pulp vitality. The aim of this study is to investigate modification of CO₃Ap cement combined with SCPC, later term as CO₃Ap-SCPC cement (CAS) in means of its chemical (Calcium release) and physical properties (setting time, DTS and pH value). Methods: The study consist of three groups;group 1 (100% calcium hydroxide, group 2 CO₃Ap (60% DCPA: 40% vaterite, and group 3 CAS (60% DCPA: 20% vaterite: 20% SCPC. Distilled water was employed as a solution for group 1, and 0.2 mol/L Na₃PO₄ used for group 2 and group 3. Samples were evaluated with respect to important properties for pulp capping application such as pH, setting time, mechanical strength and calcium release evaluation. Results: The fastest setting time was in CO₃Ap cement group without SCPC, while the addition of 20% SCPC slightly increase the pH value but did not improved the cement mechanical strength, however, the mechanical strength of both CO₃Ap groups were significantly higher than calcium hydroxide. All three groups released calcium ions and had alkaline pH. Highest pH level, as well as calcium released level, was in the control group. Conclusion: The CAS cement had good mechanical and acceptable chemical properties for pulp capping application compared to calcium hydroxide as a gold standard. However, improvements and in vivo studies are to be carried out with the further development of this material. © The Author(s).

关键词： Carbonate apatite CO3Ap-SCPC cement Pulp capping Silica-calcium phosphate composite

来源：评论

学校读者我要写书评

暂无评论

The quality and quantity improvement efforts for Geblek Kulonprogo as a millennial healthy snack

引用

Journal of Physics: Conference Series 2020年第1期1446卷

作者： Ratnaningsih Devi, M K Sugati, D Food Processing Education Department Universitas Negeri Yogyakarta Indonesia Urban and Regional Planning Study Program Institut Teknologi Nasional Yogyakarta Indonesia Mechanical Engineering Department Institut Teknologi Nasional Yogyakarta Indonesia

Geblek is a traditional food made from wet cassava starch that has become an icon of Kulonprogo District, Special Region of Yogyakarta. The characteristics of geblek are white, number eight shapes, savory taste, and chewy texture. Some problems of Small and Medium Enterprises (SME), Patimurni Andani as the producer of geblek, are the cooking equipment for geblek dough, label and packaging that do not accordance with the goverment regulation. The objective of this community service is to improve the quality and quantity of geblek production as a milenial healthy snack. The method of this study consisted of the design and manufacture of the geblek dough cooker, the nutritional composition analysis, and the improvement of label and packaging. The results of this community service showed that the specifications for the geblek dough cooker were 75 cm in height and 45 cm in diameter, the material was from stainless steel 304, the maximum pressure was 5 kg/cm2, the maximum temperature was 145°C, the tank volume was 190 liters, the capacity was 150 kg, and the gas consumption was 0.8 kg/hour. These results suggested that the quality and quantity improvement of geblek could be implemented in SME to produce it as healthy snacks.

关键词：

来源：评论

学校读者我要写书评

暂无评论

The effect of air temperature on rice drying rate using vertical drying machine

引用

IOP Conference Series. Earth and Environmental Science 2019年第1期355卷

作者： Syahrul Bahri, S Mirmanto, M Nurchayati Sukmawaty Putra, GMD Mechanical Engineering Department Mataram University Indonesia Agricultural Engineering Study Program Mataram University Indonesia

mechanical dryer usually using heat from combustion and air is blown through heater to the product dried. This study was conducted used a vertical dryer. The purpose of this study was to find out the effect of air temperature to drying rate and drying efficiency. The variation of the temperature used were 50°C, 55°C, and 60°C with a tolerance of ± 1 °C with a constant mass of 20kg. The result of this study showed that the higher the dryer air temperature used, the faster the drying rate and drying time. It was found that the fastest drying rate for 60°C was 0.00033804 kg/s with drying time 70 minutes. While for temperature of 50°C found the longest drying rate of to reach a moisture content of 13.8% of 0.00022571 kg/s with constant air velocity of 5 m/s. The highest dried efficiency occurs at a temperature 60°C.

关键词：

来源：评论

学校读者我要写书评

暂无评论

The development of bank applications for debtors' selection by using Naïve Bayes classifier technique

The development of bank applications for debtors' selection ...

引用

International Conference on Informatics, engineering, Science and Technology, INCITEST 2018

作者： Ginting, S.L.B. Adler, J. Ginting, Y.R. Kurniadi, A.H. Study Program of Computer System Universitas Komputer Indonesia Jl. Dipati Ukur 112-116 Bandung40132 Indonesia Department of Mechanical Engineering Universitas Riau Kampus Bina Widya KM 12 Simpang Baru Pekanbaru28293 Indonesia

The purpose of this study is to create an application which functions automatically with high accuracy when analyzing bank customer data. This needed due to non-perforMing loans occurring frequently caused by the inaccuracy of credit analysts in the assessment of creditworthiness. This can be seen in the incident occurred in a public bank located in Bandung. This bank does not have the database that serves to accommodate data history and the method used in assessing creditworthiness is merely based on the simple statistical analysis. This leads to reduced accuracy and speed in the decision-making process. This research applies Naïve Bayes Classifier (NBC) method, a Data Mining technique. This helps credit analysts to select customers who are truly eligible to be given credit so that non-perforMing loan can be avoided. NBC calculates the probability of one class from each group of attributes and deterMines which class is most optimal. The accuracy of the NBC sampling test from 501 data is 94% compared to the decision made by a credit analyst. It can be concluded that this application is very helpful for credit analysts in recommending customers who are eligible for a loan to the bank's decision maker. © Published under licence by IOP Publishing Ltd.

关键词： Sales

来源：评论

学校读者我要写书评

暂无评论

Overview of Hysteresis Current Controller Application in Renewable Energy Based Power Systems

引用

IOP Conference Series: Materials Science and engineering 2019年第1期536卷

作者： A. M. Shiddiq Yunus Sri Swasti Purwito Energy Conversion Study Program Mechanical Engineering Department Politeknik Negeri Ujung Pandang Indonesia Electric Power Engineering Study Program Electrical Engineering Department Politeknik Negeri Ujung Pandang Indonesia

This paper presents an overview of the Hysteresis Current Controller (HCC) application in Renewable Energy Based Power System. The beginning concept of HCC is considered to be formally introduced by Thomas M. Freederiksen and Ronald W. Russel in 1971 that was registered in US Patent No. US3725673. The fundamental principle of HCC is based on the comparison of the instantaneous load current to the instantaneous sine wave reference where the difference between the two is maintained within the defined upper and lower band. There are some advantages of using HCC including simple, insensitivity to load parameters variations, fast dynamic response and inherent maximum current limiting characteristics. Therefore, based on its robustness, HCC has currently applied also in renewable energy based power plants such as PV converter system, Power Electronics System of Wind Energy, and in SMES control system for Wind Energy Application. However, the drawback of HCC system was also discussed in some papers compared with other control systems, for instant HCC is giving high chattering in torque in IM drive test. Therefore the combination of HCC with other controllers also becomes a new trend to improve the applied system that involving HCC as the main controller.

关键词：

来源：评论

学校读者我要写书评

暂无评论

The Development of Bank Application for Debtors Selection by Using Naïve Bayes Classifier Technique

The Development of Bank Application for Debtors Selection by...

引用

International Conference on Informatics, engineering, Science and Technology, INCITEST 2018

作者： Ginting, S.L.B. Adler, J. Ginting, Y.R. Kurniadi, A.H. Computer System Study Program Universitas Komputer Indonesia Jl. Dipati Ukur 112-116 Bandung40132 Indonesia Department of Mechanical Engineering Universitas Riau Kampus Bina Widya KM 12 Simpang Baru 5 Pekanbaru28293 Indonesia

The purpose of this study is to create an application that functions automatically with high accuracy when analyzing bank customer data. This needed due to non-perforMing loans occurring frequently caused by the inaccuracy of credit analysts in the assessment of creditworthiness. This can be seen in the incident occurred in a public bank located in Bandung. This bank does not have the database that serves to accommodate data history and the method used in assessing creditworthiness is merely based on the simple statistical analysis. This leads to reduced accuracy and speed in the decision-making process. This research applies Naïve Bayes Classifier (NBC) method, a Data Mining technique. This helps credit analysts to select customers who are truly eligible to be given credit so that non-perforMing loan can be avoided. NBC calculates the probability of one class from each group of attributes and deterMines which class is most optimal. The accuracy of the NBC sampling test from 500 data is 95% compared to the decision made by a credit analyst. It can be concluded that this application is very helpful for credit analysts in recommending customers who are eligible for a loan to the bank's decision maker. © Published under licence by IOP Publishing Ltd.

关键词： Sales

来源：评论

学校读者我要写书评

暂无评论

Impacts of Grid Frequency Variation on Dynamic Performance of DFIG Based Wind Turbine

引用

IOP Conference Series: Materials Science and engineering 2019年第1期619卷

作者： A. M. Shiddiq Yunus Energy Conversion Study Program Mechanical Engineering Department Politeknik Negeri Ujung Pandang Indonesia

Wind energy is one of popular sources of renewable energy that massively used to generate electric power nowadays. Among wind generator technologies, Doubly Fed Induction Generator (DFIG) is placed as the first dominant wind generator type that is installed worldwide since 2004. Its popularity is due to the advantages of its capability to extract more energy compare to the fixed speed type. Moreover, it uses only one-third converter size which reduced the total construction cost compared to its closest rival, Full Converter Wind Turbine Generator Type. Although DFIG widely installed worldwide, it is in fact, very sensitive to the grid disturbances such as frequency variation. Based on IEEE standard for 60 Hz system, a power system should not be allowed to work in less than 59.3 Hz or more than 60.5 Hz. In this paper, DFIG-grid connected is extensively simulated in the condition of frequency variation that is carried out using Matlab/Simulink. The results show that some important parameters such as power output of the generator, voltage at point of common coupling, voltage at DC link and generator speed are experiencing significant rise/drop which in turn might damage the wind turbine generator.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Effect of contact surface temperature on wear of nickel-chromium layer

引用

AIP Conference Proceedings 2019年第1期2187卷

作者： I. M. Widiyarta I. M. Parwata I. P. Lokantara Dwipayana 1Study Program of Mechanical Engineering Faculty of Engineering Udayana University Indonesia 2Magister of Mechanical Engineering Faculty of Engineering Udayana University Indonesia

In sliding contact of two components, the contact temperature will be generated due to the friction force and this may weaken the material and cause the material to be less resistance to fail by wear. However, the generated temperature may develop oxide layers at the surface and thus may protect the material to fail by wear. In this work, the contact surface of the material of the medium carbon steel was coated with Nickel-Chromium in the process of flame powder spray coating. To determine the effect of the elevated temperature at the contact surface on the wear of the Nickel-Chromium layers, the wear test with the various temperatures of the surface was performed using the ball-on-plat wear test machine. The surface temperature was arranged in the range of 30, 50, 100, 150, 200, 250 and 300°C. The results show that the wear rate decrease from about 0.0347x10−3 to 0.0083x10−3 gr/m with increasing the surface temperature from 30°C to 50°C and increasing the surface temperature up to 300°C, the wear rate slightly fluctuated between 0.0023x10−3 and 0.0053x10−3 gr/m. This wear rate behavior occurred because of the oxide layers presented at the surface due to the elevated temperature.

关键词：

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：