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"Konduktivitas kalor (k) adalah sebuah nilai yang menyatakan kemampuan suatu material (padat, cair dan gas) untuk menghantarkan energi. Terdapat berbagai macam alat pengukuran untuk mengukur nilai nilai konduktivitas kalor berdasarkan jenis material nya. Pada penelitian ini akan membuat sebuah inovasi di alat pengukuran konduktivitas kalor untuk material padat yaitu yang lebih portabel dengan dasar pemikiran yaitu memodifikasi alat pengukuran konduktivitas kalor buatan Ogawa Seiki. Alat pengukuran buatan Ogawa Seiki ini memiliki dimensi yang besar sehingga memerlukan ruang yang cukup besar serta tidak mudah dipindahkan dari suatu tempat ke tempat yang lain. Metode dalam alat pengukuran yang akan dibuat ini adalah metode Axial Flow yaitu mengalirnya energi kalor dari sisi pemanas ke sisi pendingin dalam arah vertikal. Metode perhitungan nya akan mengikuti metode perhitungan alat Ogawa Seiki. Pengujian yang dilakukan untuk melihat nilai kesalahan dari alat pengukuran ini dan hasilnya adalah 4-10% nilai kesalahannya untuk material dari nilai konduktivitas kalornya bernilai 15-200 W/m K serta 139% untuk material yang bernilai 0.2 W/ m K. Dari hasil tersebut disimpulkan bahwa alat ini hanya mampu menghitung nilai untuk material logam.

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The thermal conductivity (k) is a value that represents the ability of a material (solid, liquid and gas) to conduct energy. There are various kinds of measurement apparatus for measuring thermal conductivity values ​​based on the type of material. This research will make an innovation in the thermal conductivity measurement apparatus for solid material, which is more portable with the basic idea of ​​modifying the thermal conductivity measurement apparatus made by Ogawa Seiki. This measurement apparatus made by Ogawa Seiki has large dimensions so it requires a large enough space and is not easily moved from one place to another. The method in the measurement apparatus to be made is the Axial Flow method which means the flow of thermal energy from the heater side to the cooler side in the vertical direction. The calculation method will same with Ogawa Seiki calculation method. The preliminary test carried out to see the error value of this measurement apparatus and the result are 4-10% of the error value for the material of the heating conductivity value is 15-200 W / m K and 139% for material that is worth 0.2 W / m K. From these results it was concluded that this apparatus measurement was only able to calculate metal material.,"

"Nanofluida adalah fluida penghantar panas yang mengandung partikel berukuran nano ( 1 – 100 nm). Penelitian yang dilakukan membahas karakterisasi nanofluida berbahan dasar fraksi non-logam dari limbah elektronik Printed Circuit Board (PCB) yang didominasi kandungan SiO2. Karakterisasi berfokus pada pengaruh konsentrasi partikel (0; 0,1; 0,3; dan 0,5%) dan surfaktan Cetyltrimethylammonium bromida (CTAB) (0; 3; 5; dan 7%) terhadap kondktivitas termal, viskositas, dan zeta potensial nanofluida. Hasil pengujian Particle Size Analyzer (PSA) pada partikel menunjukkan terjadinya peningkatan ukuran partikel dari 268,7 d.nm menjadi 1035,6 d.nm (milling 10 jam) dan 572,6 d.nm (milling 20 jam), sehingga partikel tidak mencapai ukuran nano dan tergolong kedalam micro-dispersed thermal fluid. Nilai konduktivitas termal mengalami penurunan seiring meningkatnya konsentrasi partikel dan surfaktan dengan nilai tertinggi pada sampel 0,5% partikel dan 0% CTAB sebesar 0,764 W/mK. Nilai viskositas mengalami peningkatan linear seiring dengan penambahan konsentrasi partikel dan surfaktan dengan nilai tertinggi pada sampel 0,5% partikel dan 7% CTAB sebesar 2,658 mPa.s. Nilai zeta potensial mengalami peningkatan seiring penambahan konsentrasi partikel dan surfaktan hingga titik optimumnya pada sampel 5% CTAB dengan hasil zeta potensial 43 mV.

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Nanofluids are heat transfer fluids that contain nano-sized particles (1-100 nm). The conducted research discusses the characterization of nanofluids based on the non-metallic fraction of Printed Circuit Board (PCB) electronic waste, predominantly containing SiO2. The characterization focuses on the influence of particle concentration (0, 0.1, 0.3, and 0.5%) and Cetyltrimethylammonium bromide (CTAB) surfactant (0, 3, 5, and 7%) on the thermal conductivity, viscosity, and zeta potential of the nanofluids. Particle Size Analyzer (PSA) testing results on the particles indicate an increase in particle size from 268.7 d.nm to 1035.6 d.nm (after 10 hours of milling) and 572.6 d.nm (after 20 hours of milling), indicating that the particles do not reach the nano size and belong to the category of micro-dispersed thermal fluid. The thermal conductivity value decreases with increasing particle and surfactant concentrations, with the highest value observed in the sample with 0.5% particles and 0% CTAB, amounting to 0.764 W/mK. The viscosity value shows a linear increase with the addition of particle and surfactant concentrations, reaching the highest value in the sample with 0.5% particles and 7% CTAB, at 2.658 mPa.s. The zeta potential value increases with increasing particle and surfactant concentrations until reaching the optimum point in the sample with 5% CTAB, resulting in a zeta potential of 43 mV."

"This paper reports onthe investigation of thermal properties of Kapok, Coconut fibre and Sugarcanebagasse composite materials using molasses as a binder. The composite materials were moulded into12 cylindrical samples using Kapok, Bagasse, Coconut fibre, Kapok and Bagassein the ratios of (70:30; 50:50 and 30:70), Kapok and Coconut fibre in theratios of (70:30; 50:50 and 30:70), as well as a combination of Kapok, Bagasseand Coconut fibre in ratios of (50:10:40; 50:40:10 and 50:30:20). The sample size is a 60 mmdiameter with 10?22 mm thickness compressed at a constant load of 180 N using a Budenbergcompression machine. Thermal conductivity and diffusivity tests were carriedout using thermocouples and theresults were read out on a Digital Multimeter MY64 (Model:MBEB094816), whilea Digital fluke K/J thermocouple meter PRD-011 (S/NO 6835050) was used to obtain thetemperature measurement for diffusivity. It was observed that of all the twelvesamples moulded, Bagasse, Kapok plus Bagasse (50:50), Kapok plus Coconut fibre(50:50) and Kapok plus Bagasse plus Coconut fibre (50:40:10) has the lowestthermal conductivity of 0.0074, 0.0106, 0.0132, and 0.0127 W/(m-K) respectivelyand the highestthermal resistivity. In this regard, Bagasse has the lowest thermalconductivity followed by Kapok plus Bagasse (50:50), Kapok plus Bagasse plusCoconut fibre (50:40:10) and Kapok plus Coconut fibre (50:50)."

"Termoelektrik adalah fenomena yang berhubungan dengan perubahan temperatur dan beda potensial. Banyaknya aplikasi dari termoelektrik mendorong penelitian tentang material termoelektrik di Departemen Fisika Universitas Indonesia. Performa material termoelektrik dapat dihitung menggunakan nilai figure of merit. Untuk menghitungnya dibutuhkan nilai koefisien seebeck, konduktivitas listrik, dan konduktivitas panas. Seluruh nilai tersebut bisa didapatkan melalui sistem karakterisasi material termoelektrik yang memiliki sistem pengendalian temperatur dan arus listrik di dalamnya. Sumber arus dibuat memanfaatkan DAC dan rangkaian op-amp. Sumber arus yang digunakan memiliki tiga rentang arus yang dapat digunakan yaitu, 0-50 mA, 0-10 mA, dan 0-5 mA. Untuk menjaga temperatur probe dingin di suhu ruang, dilakukan pengendalian menggunakan metode Direct Synthesis dengan nilai Kc = 1,24 dan 𝜏𝐼 = 310. Sementara pada pengendalian temperatur pemanas, digunakan metode IMC dengan nilai Kc = 1,238, 𝜏𝐼 = 1122s dan , 𝜏𝐷 = 38,574s.

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Thermoelectric is a phenomenon related to temperature changes and potential differences. Many applications of thermoelectrics encourage research on thermoelectric materials in the Department of Physics Universitas Indonesia. Thermoelectric material performance can be calculated using a reasonable number value. To calculate the required values for the seebeck coefficient, electrical conductivity, and heat conductivity. All of these values can be obtained through the thermoelectric material characterization system which has a temperature and electric current control system in it. Electric current source is made using DAC and op-amp circuit. This electric current source has three ranges of current that can be used, namely, 0-50 mA, 0-10 mA, and 0-5 mA. To keep the temperature of the cold probe at room temperature, control was carried out using the Direct Synthesis method with a value of Kc = 1,24 and 𝜏𝐼 = 310. While at heating temperature, the IMC method was used with a value of Kc = 1,238, 𝜏𝐼 = 1122s dan , 𝜏𝐷 = 38,574s."

"This paper reports on the investigation of thermal properties of Kapok, Coconut fibre and Sugarcane bagasse composite materials using molasses as a binder. The composite materials were moulded into 12 cylindrical samples using Kapok, Bagasse, Coconut fibre, Kapok and Bagasse in the ratios of (70:30; 50:50 and 30:70), Kapok and Coconut fibre in the ratios of (70:30; 50:50 and 30:70), as well as a combination of Kapok, Bagasse and Coconut fibre in ratios of (50:10:40; 50:40:10 and 50:30:20). The sample size is a 60mm diameter with 10mm – 22mm thickness compressed at a constant load of 180N using a Budenberg compression machine. Thermal conductivity and diffusivity tests were carried out using thermocouples and the results were read out on a Digital Multimeter MY64 (Model: MBEB094816), while a Digital fluke K/J thermocouple meter PRD-011 (S/NO 6835050) was used to obtain the temperature measurement for diffusivity. It was observed that of all the twelve samples moulded, Bagasse, Kapok plus Bagasse (50:50), Kapok plus Coconut fibre (50:50) and Kapok plus Bagasse plus Coconut fibre (50:40:10) has the lowest thermal conductivity of 0.0074, 0.0106, 0.0132, and 0.0127 W/(m-K) respectively and the highest thermal resistivity. In this regard, Bagasse has the lowest thermal conductivity followed by Kapok plus Bagasse (50:50), Kapok plus Bagasse plus Coconut fibre (50:40:10) and Kapok plus Coconut fibre (50:50)."

"Experimentation on and implementation of phase-change materials for thermal storage is attracting increasing attention by those seeking a potential resolution to energy issues. This study investigates beeswax as a high thermal-capacity phase-change material with the objective of analyzing the thermal properties and behaviors of beeswax/CuO nano-PCM. The study uses differential scanning calorimetry apparatus to measure the melting temperature and thermal capacity of nano-PCMs. The study found nano-PCM melting temperatures of 63.62°C, 63.59°C, 63.66°C, 63.19°C, and 62.45°C at 0.05, 0.1, 0.15, 0.2, and 0.25 wt%, respectively. FTIR testing found no chemical reaction between CuO and beeswax. The existence of CuO nanoparticles enhanced thermal conductivity of beeswax but reduced its heat capacity. However, the change in latent heat caused no significant effects in the performance of beeswax/CuO. Thus, the results showed that heat transfer of composite beeswax/CuO melts faster than base phase-change material"

"The purpose of this paper is to analyse the thermal conductivity of carbon/basalt fiber reinforced hybrid composite structures based on stacking sequences. The paper also investigates the thermal impedance of carbon fiber reinforced polymer (CFRP) and basalt fiber reinforced polymer (BFRP) with increased thickness. Research involved processing hybrid composite by using injection moulding. The weight ratios of fibers to polymers was 60%: 40%. Testing was conducted using the ASTM D 5470 standard test method. Results show that the stacking sequences of carbon/basalt fibers have a significant impact on thermal conductivity. Hybrid composite with the stacking sequence mode C3B4C3 has the lowest thermal conductivity at 0.187 W/mK, and the highest thermal impedance of 0.0052 m2K/W. The highest thermal impedance of BFRP is at 0.007 m2K/W with 2.5 mm thickness. In CFRP, the highest thermal impedance is achieved by 3.4 mm thickness with 0.005 m2K/W. Results therefore show that carbon/basalt/epoxy hybrid composites are good insulators, since thermal conductivity is less than 0.42 W/moK standard."

"Silikon merupakan salah satu unsur yang paling umum terdapat di alam semesta ini. Di zaman modern ini, kebutuhan akan unsur silikon sangatlah tinggi. Hal ini dikarenakan sifatnya yang dapat berperan sebagai semikonduktor, membuatnya sangat dibutuhkan dalam produksi berbagai macam kebutuhan peralatan elektronik salah satunya sel fotovoltaik. Namun untuk memperoleh tingkat kemurnian tersebut hanya terdapat 2 cara yang yaitu melalui metode Czochralski dan DSS furnace. Kedua proses ini sangatlah mahal untuk diterapkan, oleh karenanya untuk meningkatkan kualitas dari produksinya diperlukan suatu perhitungan menggunakan metode CFD agar didapatkan solusi yang optimal sebelum diterapkan langsung ke mesin furnace. Pada penelitian ini proses CFD dilakukan dengan menggunakan software ANSYS Fluent. Adapun permodelan yang dilakukan adalah berdasarkan eksperimen langsung yang sudah pernah dilakukan sebelumnya. Fokus pembahasan dalam penelitian ini adalah pengaruh perbedaan karakteristik material grafit yang digunakan dalam struktur furnace terhadap solid-liquid interface yang terbentuk selama proses solidifikasi silikon ingot. Proses permodelan dilakukan dalam metode transient dengan mengaktifkan fungsi-fungsi seperti energi, radiasi, dan solidification & melting. Adapun metode perhitungan radiasi yang digunakan adalah model S2S (surface to surface) dan aliran dianggap laminar. Dari penelitian yang dilakukan ditemukan hasil bahwa permodelan sistem DSS furnace dapat diterapkan dengan memanfaatkan ANSYS Fluent. Dan juga dibuktikan bahwa karakteristik dari grafit yang digunakan dalam sistem mempengaruhi proses solidifikasi yang terjadi. Dalam penelitian ini dibuktikan bahwa grafit dengan nilai thermal conductivity 140 W/mK mengalami proses solidifikasi yang lebih cepat dibandingkan dengan kedua material grafit lainnya yang memiliki nilai thermal conductivity lebih rendah.

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Silicon is one of the most common elements found in the universe. In the modern era, there is a high demand for silicon due to its unique properties as a semiconductor, making it essential in the production of various electronic devices, including photovoltaic cells. However, achieving the required level of purity poses a challenge, and there are only two methods, namely the Czochralski and DSS furnace methods, to attain it. Both processes are expensive to implement. Therefore, to enhance the production quality, calculations using Computational Fluid Dynamics (CFD) are necessary to obtain optimal solutions before direct application to the furnace machine. In this study, CFD simulations were performed using ANSYS Fluent software, based on direct experiments conducted previously. The focus of the research is on understanding the influence of different characteristics of graphite material used in the furnace structure on the solid-liquid interface formation during the silicon ingot solidification process. The transient method was employed in the modeling process, activating functions such as energy, radiation, and solidification & melting. The radiation calculation method utilized the Surface-to-Surface (S2S) model, and the flow was assumed to be laminar. The results of the study indicated that the DSS furnace system modeling could be applied effectively using ANSYS Fluent. Furthermore, it was demonstrated that the characteristics of the graphite used in the system significantly affected the solidification process. The research provided evidence that graphite with a thermal conductivity value of 140 W/mK underwent a faster solidification process compared to the other two graphite materials with lower thermal conductivity values."

"Saat ini kebutuhkan akan computer/laptop semakin meningkat. Laptop dengan performa tinggi akan menghasilkan energi yang besar sehingga akan membuat laptop panas. Untuk menghindari hal tersebut maka dibutuhkan sistem pendingin. Saat ini system pendingin pada laptop terbuat dari tembaga. Tembaga memiliki kekurangan dimana biaya yang mahal serta berat. Karena hal tersebut maka ditambahkan aluminium untuk memangkas biaya serta membuat sistem pendingin yang lebih ringan tanpa mengurangi secara signifikan konduktivitas termal yang dimiliki tembaga. Pada penilitian ini akan menjelaskan mengenai metode powder in sealed tube dengan variable berupa temperatur sintering yaitu 3000C, 4000C, dan 5000C. Sampe yang sudah difabrikasi akan dilakukan karakterisasi dengan menggunakan SEM dan EDS untuk melihat strukturmikro yang dihasilkan. Selain itu juga dilakukan pengujian densitas, porositas, kekerasan, dan konduktivitas termal. Dari hasil yang didapat menyatakan bahwa semakin tinggi temperature sintering yang dilakukan maka akan semakin tinggi pula densitas yang dimiliki sampel serta akan menurunkan porositas. Selain itu seiring bertambahnya temperatur sintering nilai kekerasan dan konduktivitas termal pada sampel akan semakin meningkat.

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Currently the need for computers/laptops is increasing. Laptops with high performance will produce a lot of energy so that it will make the laptop hot. To avoid this, a cooling system is needed. Currently the cooling system on laptops is made of copper. Copper has the disadvantage of being expensive and heavy. Because of this, aluminum was added to cut costs and create a lighter cooling system without significantly reducing the thermal conductivity of copper. This research will explain about the powder in sealed tube method with variable sintering temperature, namely 3000C, 4000C, and 5000C. The fabricated samples will be characterized using SEM and EDS to see the resulting microstructure. In addition, density, porosity, hardness, and thermal conductivity tests were also carried out. From the results obtained, it is stated that the higher the sintering temperature, the higher the density of the sample and the lower the porosity. In addition, as the sintering temperature increases, the hardness and thermal conductivity of the sample will increase."

"ABSTRAKKonduktivitas kalor merupakan salah satu karateristik material yang sangat penting di ketahui dalam aplikasi di bidang teknik yang menyangkut perpindahan kalor. Angka konduktivitas kalor menunjukan kuantitas panas yang dapat melalui unit luas pada jarak tertentu dengan gradien temperatur tertentu. Untuk bahan bangunan lokal, informasi mengenai nilai konduktivitas kalornya belum mencukupi oleh karena itu pengujian bahan bangunan lokal dilakukan.Penelitian ini dilakukan dengan menggunakan peralatan Thermal Conductivity Measuring Apparatus. Dari bahan bangunan yang diteliti diperoleh data yang menunjukan bahwa bahan bangunan tersebut termasuk kelompok bahan isolator.

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ABSTRACTThermal Conductivity Measurement For The Local Building Material Thermal conductivity is one of the material characteristics that is important to know in the application of engineering dealing with heat transfer. Thermal conductivity value shows the quantity of thermal that passes through an area unit at a certain distance and temperature gradient. The information about thermal conductivity value for the local building material is not sufficient, so that an experiment is needed.The experiment is carried out by means of Thermal Conductivity Measuring Apparatus. It is resulted from the experiment that the local building material is put into isolator group."