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Heat exchangers are used to transferring energy (heat), using fluids or gases, both hot and cold, from one area to another due to temperature differences. Almost all agricultural wastes serve as carbon products which are essential to produce graphene oxide, it is very possible to get graphene oxide by synthesizing it from agricultural waste which is expected to reduce the amount of waste on the earth. After carrying out the synthesis, it is necessary to test the characterization of the resulting product. The characterization stage requires a sintering process (20oC to 98oC) until the product is completely solidified. This research aims to design a heat exchanger that is highly effective in assisting the sintering process. For the design to be well-directed, several things must be done, such as calculating the main components (shell and tube) and designing a heat exchanger. Based on the TEMA standard and the use of simple calculations that refer to the attached calculation formula using Ms. Excel, hot and cold fluids used in this heat exchanger design are ethylene glycol and water. The length of the shell and tube as a whole is 5 m, the inner and outer shell diameters are 254 mm and 279.4 mm; the inner and outer tube diameters are respectively 22.09 mm and 25.40 mm. The calculation results show an excellent design effectiveness value of 86.14%. Continuous innovation in the design and materials of the heat exchanger can increase the effectiveness value to close to 100% so that it can help the graphene oxide synthesis process to make it cheaper and more efficient.

Nanopartikel Fe3O4 merupakan jenis nanopartikel yang berperan penting dalam kehidupan industri. Namun, masih jarang ditemukan proses sintesis Fe3O4 menggunakan sistem heat exchanger pada skala industri sehingga penelitian ini dilakukan untuk merancang heat exchanger jenis shell and tube dalam proses produksi nanopartikel Fe3O4 pada skala industri. Metode yang digunakan pada penelitian ini yaitu perhitungan matematis menggunakan lebih dari 20 persamaan yang diturunkan berdasarkan pengaruh dimensi dan spesifikasi fluida dan kemudian data yang diperoleh diolah dengan menggunakan aplikasi Microsoft Excel. Rancangan alat HE memiliki spesifikasi panjang tube 4,572 m, diameter tube 0,0254 m, dan ketebalannya 0,0018 m. Lalu data diolah menggunakan software pengolah data Microsoft Excel. Hasilnya menunjukkan bahwa rancagan heat exchanger jenis shell and tube ini memiliki nilai efektivitas 93% dengan faktor kemurnian 0,01 jam.ft2.oF/Btu. Dari penelitian ini diketahui jenis HE shell and tube yang dirancang belum sesuai dengan standar yang telah ditetapkan oleh industri.

The objective of this study is to develop a new environmentally-friendly brake pad made from eggshells (Es) and banana peels (BPs) as reinforcement agents. E and BP particles as dual reinforcement with various compositions were combined. The E/BP mixture was then embedded on a polymer matrix composing a resin/hardener mixture in a 1:1 ratio. As a standard, brake pads using a single reinforcement of E and BP particles were also fabricated. Physical properties (i.e. particle size, surface roughness, morphology, and density), as well as mechanical properties (i.e. hardness, wear rate, and friction coefficient properties) were investigated. It was observed that using dual reinforcements was preferable (compared to using single reinforcements) because they had a synergistic effect on the mechanical properties of the brake pad. The best mechanical properties were found in dual reinforcements of brake pad specimens using E/BP particles with a higher BP ratio in which the value of the stiffness test, puncture test, wear rate, and coefficient of friction were 4.5 MPa, 86.80, 0.093×10-4 g/s.mm2, and 1.67×10-4, respectively. A high BP particle ratio played a dominant role in dual reinforcements, increasing the resin's bonding ability and resulting in good adhesion between the reinforcement and matrix. When compared to commercial brake pads, the brake pad specimens fabricated in this study met the standards. The techno-economic analysis also confirmed the prospective production of brake pads from E and BP particles (compared to commercial brake pads). From this research, it is expected that environmentally friendly and low-cost brake pads can be used to replace the dangerous friction materials.

The purpose of this study was to analyze the effect of a resin composition on the performance of brake pads with durian seeds (BDs) as the base material. Experiments were done by attaching saw-milled BD particles to a polymer matrix. Various resin compositions were used for preparing the brake pad, which was then tested (press test, puncture test, and friction test). Physical properties (i.e., particle size, surface roughness, morphology, and density), as well as mechanical properties (ie: hardness, wear rate, and friction coefficient properties), were investigated. Based on observations, the best mechanical properties were found in the highest resin mixture, reaching a compressive strength value of 2.4 MPa. The impact of the homogeneity of the brake pad filler particles is the main reason. The high resin composition causes more cross-links to be formed. This research demonstrates the prospective environmentally friendly and inexpensive brake pads used to replace current products that use hazardous materials.

The objective of this study was to investigate isotherm adsorption of carbon microparticles from pineapple peel waste. Carbon microparticles were prepared by carbonizing pineapple peel waste at 215-250°C and grinding using a saw-milling process. To investigate adsorption properties of carbon microparticles, experiments were done by evaluating adsorption of curcumin (as a model of adsorbate) in the ambient temperature and pressure under constant pH condition. To confirm the adsorption characteristics, carbon particles with different sizes (i.e., 100, 125, and 200 ?m) were tested, and the adsorption results were compared with several standard isotherm adsorption models: Langmuir, Freundlich, Temkin, and Dubinin- Radushkevich. To support the adsorption analysis, several characterizations (i.e., optical microscope, sieve test, and Fourier transform infrared analysis) were conducted. The adsorption test showed that the adsorption profile is fit to the Freundlich model for all variations, indicating the multilayer adsorption process on heterogeneous surfaces and interactions between adsorbate molecules. The results from other isotherm models also confirmed that the adsorption process occurs physically via Van der Waals force in binding adsorbate on the surface of adsorbent.

Biosintesis nanopartikel emas (AuNP) menggunakan ekstrak Sargassum horneri (SH) dinilai lebih ekonomis dan terbukti menghasilkan nanopartikel emas yang berperan sebagai katalis dalam degradasi zat warna. Oleh karena itu, produksi nanopartikel emas perlu dikembangkan dalam skala industri. Penelitian ini bertujuan untuk mengetahui kelayakan proyek biosintesis nanopartikel emas menggunakan ekstrak Sargassum horneri dalam skala industri. Metode evaluasi ekonomi menggunakan analisis terhadap beberapa parameter evaluasi ekonomi seperti Gross Profit Margin (GPM), Break Even Point (BEP), Cumulative Net Present Value (CNPV), Payback Period (PBP), dan Profitability Index (PI). Hasil penelitian menunjukkan bahwa pada skala industri, jumlah produksi Nanopartikel Emas dalam setahun adalah 132 L. Total harga yang dibutuhkan untuk produksi nanopartikel emas dalam setahun adalah USD 8.573.006,05, dengan penjualan tahunan USD 13.200.000, sehingga total biaya adalah USD 4.626.993,95 USD per tahun. Dalam kondisi ideal, analisis PBP menunjukkan bahwa proyek akan menguntungkan pada tahun ke-3, dan analisis PI menunjukkan bahwa biaya modal awal dapat diperoleh kembali dari tahun ke-3. Analisis terhadap beberapa kondisi tidak ideal menunjukkan bahwa kerugian proyek dapat terjadi. Berdasarkan evaluasi ekonomi, proyek ini dapat dilakukan dengan mengantisipasi kerugian yang akan terjadi akibat perubahan beberapa kondisi ideal.

The purpose of this study was to evaluate the feasibility study in the production of sieve shaker for teaching particle size to students with visual impairment. The sieve shaker is important as a tool for giving understanding the definition of particles and their sizes, while this equipment has been well developed for engineering purposes. Different from other sieve shakers that are expensive, the present sieve shaker is just for educational goals only (especially for being used in developing countries), making the design of this equipment to be simpler, user friendlier, and more portable. The feasibility study was done from the engineering and economic perspective. Engineering analysis was performed based on a simple mass balance analysis, added it into the calculation of scale-up production from commercially available apparatuses. Economic evaluation was carried out using a number of economic parameters, including gross profit margin, payback period, and net profit value, in which all calculations were done under ideal and non-ideal condition (labor conditions, sales and raw materials, utilities, as well as external conditions and environmental uncertainties (competition, taxes and subsidiaries)) in 20 years of project. All prices, utilizing components, and specifications for the apparatuses used in the scale-up production were taken based on the available online shopping web. The results of the engineering confirmed that the project was potential conducted even it is in small-scale industries because all processing steps could be carried out using simple equipment and commercially available in the market. Economic evaluation results showed positive values for all economic parameters with a few exceptions. This research was complemented by some basic theories to support the definition of sieve shaker.

This study aims to demonstrate the preparation of carbon microparticles obtained from red dragon fruit peel waste and their adsorption isotherm characteristics. The carbon microparticles were prepared by combining carbonization (at 250°C) and saw-milling process, and to get carbon microparticles with a specific size, sieve analysis was used. The adsorption isotherm was done by testing the adsorption ability of carbon microparticles with a specific size into curcumin solution in the batch-type reactor. The adsorption results were then compared to several standard isotherm models (i.e., Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich models) for understanding what phenomena happen during the adsorption process. The adsorption analysis was also confirmed by testing several sizes of the carbon microparticles to predict the proposal mechanism in the adsorption process. The analysis results showed that the multilayer adsorption process occurs for all sizes in the micrometer range, and the process involves physical interactions between adsorbate and surface of adsorbent. The existence of multilayers is due to the possibility in the existence of porous structure in the carbon microparticles. This study is important for giving an alternative solution for reusable organic waste as well as supporting the fundamental researches in the further applications of carbon particles as catalyst and adsorbent.