KARAKTERSTIK SERAPAN SUARA KOMPOSIT POLYESTER BERPENGUAT SERAT TAPIS KELAPA

The purpose of this study is to investigate of sound absorption of coconut filter fiber composites. The research material made with coconut filter fiber as reinforcement and matrix resin unsaturated polyester (UPRs) type Yukalac BQTN 157 with 1% hardener types MEKPO (Methyl Ethyl Ketone Peroxide) and fiber treatment by  0,5% KMnO4. Production methods is poltrusion and the variations of fiber volume fraction are 20, 25 and 30% and fiber length are 5, 10 and 15 mm. Testing of sound absorption frequency are 250, 500, 1000, 2000 and 4000 Hz. The results of research show that  the highest value of sound absorption coefficient is on  the composites with composition of 10 mm fiber length and 30% fiber volume fraction, that is 0.550828. The values are included in the class “Sound Absorption Coefficient Class D (Extremely absorbing)” with the range 0.40 – 0.60 based on ISO standard 11654:1997

Development of mesoporous activated carbons derived from brewed coffee waste for CO2 adsorption

The primary cause of rising CO2 concentrations in the atmosphere is the use of fossil fuels in motor vehicles and factory activities in industry. CO2 levels in the atmosphere can be controlled and reduced by using low-carbon energy and capturing and storing CO2. One widely used way for CO2 capture and storage is adsorption method. This method necessitates the use of an adsorbent, one of which is activated carbon. In this study, brewed coffee waste was converted into activated carbons, characterized, and tested for carbon dioxide adsorption. Brewed coffee waste was dehydrated at 105 ºC for an hour before being carbonized at 550 °C and activated at 670, 700, and 730 °C, with a 200-ml/min nitrogen injection during activation. Activated carbons with activation temperatures of 670, 700, and 730 °C were denoted as AC-670, AC-700, and AC-730, respectively. A series of TGA, SEM, and adsorption isotherm tests were used to determine the proximate components, surface morphology, and surface structure of the activated carbons produced. To assess the adsorption capacities of activated carbon on CO2, the gravimetric CO2 adsorption isotherm method was used. According to the findings of the study, increasing activation temperatures cause variable properties in activated carbon. When using an activation temperature of 700 °C, the most appropriate properties of activated carbon can be obtained. It has 425.843 m2/g specific surface area, 0.345 cm3/g pore volume, 3.423 nm pore diameter, 235.628 cm3/g nitrogen adsorption capacity, and 4.183 mmol/g CO2 adsorption performance. This study provided a simple way converting brewed coffee waste into activated carbon with excellent performance for CO2 adsorptio

Characteristics and performance analysis of activated carbons derived from different precursors and activators for waste water adsorption

Domestic waste such as methylene blue from the dyeing process and detergent from laundry activities are sources of water pollution. Before being dumped into the water, this waste must be minimized. One approach that can be utilized is the adsorption method with activated carbon. To generate activated carbon with the properties required for this purpose, an appropriate precursor and manufacturing conditions must be chosen. The objective of this research is to investigate the characteristics and performance of activated carbon derived from various precursors (Petung and Santong bamboos) and activators (Ar, N2, and CO2) for detergent and methylene blue dye adsorption. The difficulty to be solved is determining the best precursor and activator for maximum methyl blue and detergent adsorption. Characterizations included FTIR, XRD, SEM, TGA, and adsorption isotherm testing. The study's findings show that activated carbons have functional groups O-H (hydroxyl), C-H (aldehydes and alkenes), C=C aromatic rings, C-H aromatic groups, and an amorphous structure. The presence of a porous and amorphous structure, as well as the C=C aromatic ring, makes activated carbons capable of absorbing methyl blue and detergent. Santong bamboo-activated carbon activated with argon has the best characteristics and adsorption capability. This activated carbon has a fixed carbon content of 76.34 %, pore volumes of 0.362 cc/g, average pore widths of 1.967 nm, pore surface area of 291.487 m2/g, bimodal pore size distribution, and methylene blue and detergent adsorption capabilities of 19.733 cc/g and 1.689 cc/g, respectively. The results obtained are on a laboratory scale, which necessitates additional research, particularly on how to create reservoirs and regenerate activated carbon simply and affordabl

Analysis of Cutting Tool Modification Effect toward Force, Power and Temperature at Cutting of Material St 42

Until now, research by using of a standard cutting tool at lathe process is still become a subject of many studies in order to reduce of the force, cutting power and temperature. However, there are no satisfactory results yet as expected. In order to participate in overcoming these problems, it is conducted a study on the cutting process by using of standard cutting tool which is modified become double-edged chisel cutting tool. Variables selected in the machining process are cutting speed, feed and depth of pieces motion, due to these variables influence the change in style, cutting power and temperature will be researched. Research procedure was conducted by measuring the amount of cutting force, machining power and cutting temperature in each process multiple pieces of lathe with double-edged chisel cutting tool and then compared with using cutting tool standard. Data collected use of the data acquisition system so that the results obtained can be directly read on a computer screen. The statistical testing to be done is using a procedure paired-samples T test to determine whether use of double-edged chisel cutting tool (modified) will be better when compared with using of standard cutting tool. The result of research show that by use of double-edged chisel cutting tool can be obtained lower of the force, cutting power and temperature

Kekuatan Lentur Komposit Sandwich Serat Tapis Kelapa Dengan Core Kayu Albasia

Abstrak: Tujuan penelitian ini adalah untuk menyelidiki kekuatan lentur komposit sandwich serat tapis kelapa bermatrik polyesterdengan core kayu albasia. Bahan penelitian adalah serat tapis kelapa dengan panjang 15 mm (acak), resin unsaturatedpolyester 157 BQTN, kayu albasia dan hardener jenis MEKPO dengan konsentrasi 1%. Komposit sandwich tersusunatas dua skin dengan core ditengahnya dan dibuat dengan metode cetak tekan hidrolis. Lamina komposit sebagai skinterbuat dari serat tapis kelapa-polyester dengan fraksi volume serat 30%. Core yang digunakan adalah kayu albasiayang dipotong pada arah melintang dengan variasi ketebalan 5, 10, 15 dan 20 mm. Spesimen dan prosedur pengujianlentur mengacu pada standar ASTM C 393. Penampang patahan dilakukan foto makro untuk mengidentifikasi polakegagalannya. Hasil penelitian menunjukkan bahwa kekuatan lentur komposit sandwich semakin meningkat seiringdengan penambahan ketebalan core. Tegangan lentur komposit sandwich mempunyai nilai yang optimum padaketebalan core 15 mm. Pola kegagalan komposit sandwich yang teramati adalah kegagalan tarik pada skin kompositbagian bawah, kegagalan geser core, delaminasi skin komposit bagian atas dengan core dan kegagalan tekan skinkomposit bagaian atas.Kata kunci: komposit sandwich, albasia, kekuatan lentur, pola kegagalan Abstract: The purpose of this study was to investigate the flexural strengt of composite sandwich coconut filter fiber with albasiawood as a core. The research material is coconut filter fiber with 15 mm lenght, 157 BQTN unsaturated polyester resin,albasia wood and 1% hardener types MEKPO. Composite sandwich composed of two skins with a core in the middleand production method are a hydraulic press molding. Lamina composite as a skin made of coconut filter fiber with 30%volume fraction. Core used is albasia wood with variations in the thickness of 5, 10, 15 and 20 mm. The specimens andtesting procedures based on ASTM standards C 393. The failure of the composite sandwich will be identify by macrofotos. The results of research show that the flexural strength of composite sandwich increasing with the addition of corethickness. Flexural stress in composite sandwich has the optimum value on core thickness of 15 mm. Failure mode ofcomposit sandwich is drag failure of the bottom composite skin, shear failure of the core, delamination and the pressfailures of the top composite skin.Keywords: composite sandwich, albasia, flexural strength, failure mod

Kekuatan Lentur Komposit Polyester Berpenguat Serat Tapis Kelapa

Penelitian ini bertujuan untuk menyelidiki sifat mekanis yaitu kekuatan lentur dari kompositpolyester yang diperkuat dengan serat tapis kelapa. Di masa depan komposit ini dapatdigunakan untuk menggantikan kayu, bambu dan gipsun yang harganya mahal dan tidaktahan air. Komposit dibuat dengan memanfaatkan serat sabut kelapa dan matriks resinUnsaturated-Polyester (UPRs) jenis Yucalac 157 BQTN, campuran 1% hardener jenis MEKPO(Methyl Ethyl Ketone Peroxide) dan perendaman serat dalam larutan alkali KMnO4 0,5%.Metode produksi yang digunakan adalah press hand lay up dengan orientasi serat acak.Desain komposit dengan variasi fraksi volume serat 20, 25 dan 30% dan variasi panjang serat5, 10 dan 15 mm. Hasil penelitian menunjukkan bahwa semakin besar fraksi volume danpanjang serat dalam komposit maka kekuatan lentur semakin tinggi. Mode patahan yangteramati adalah patah getas, debonding, pullout dan crack deflection.Kata kunci: komposit, serat tapis kelapa, kekuatan lentur, mode patahan The purpose of this study is to investigate the mechanical properties i.e. flexural strength ofcomposites coconut filter fiber. In the future this material can be used to replace the wood,bamboo and gipsun which are high price and lower water resistance.The research material made with coconut filter fiber as reinforcement and matrix resinunsaturated polyester (UPRs) type Yukalac BQTN 157, with 1% hardener types MEKPO(Methyl Ethyl Ketone Peroxide) and fiber treatment by 0.5% KMnO4. Production methods arepress hand lay-up and the variations of fiber volume fraction are 20, 25 and 30% and fiberlength are 5, 10 and 15 mm. Testing of mechanical properties is flexural test (ASTM - D790)The results of research show that the longer of fiber and the bigger of fiber volume fraction,the higher of flexural strength are obtained. The fracture mode are overload, debonding ,pullout and crack deflectionKeywords : composites, coconut filter fiber, flexural strength, fracture mod

Pengaruh perlakuan serat tapis kelapa terhadap kekuatan lentur skin komposit sandwich

Abstrak Penggunaan serat alam sebagai penguat komposit semakin berkembang. Indonesia sebagai negara beriklim tropis menghasilkan berbagai jenis serat alami seperti rami, abaca, agave, serat sabut kelapa dan serat tapis kelapa. Penelitian ini bertujuan untuk menyelidiki pengaruh perlakuan alkali serat (NaOH 5%) terhadap kekuatan lentur komposit sandwich serat tapis kelapa bermatrik polyester dengan core kayu albasia Bahan penelitian adalah serat tapis kelapa dengan panjang 15 mm, resin unsaturated polyester 157 BQTN, kayu albasia dan NaOH. Hardener yang digunakan adalah MEKPO dengan konsentrasi 1%. Serat tapis kelapa yang digunakan terdiri dari serat tanpa perlakuan dan dengan perlakuan alkali 2 jam. Komposit sandwich tersusun atas dua skin dengan core ditengahnya dan dibuat dengan metode cetak tekan hidrolis. Lamina komposit sebagai skin terbuat dari serat tapis kelapa-polyester dengan fraksi volume serat 30%. Spesimen dan prosedur pengujian lentur mengacu pada standar ASTM C 393. Penampang patahan dilakukan foto makro untuk mengidentifikasi pola kegagalannya.Hasil penelitian menunjukkan serat yang mendapatkan perlakuan alkali 2 jam NaOH menghasilkan kekuatan lentur yang lebih tinggi. Hal ini disebabkan karena perlakuan alkali pada serat tapis kelapa dapat membersihkan lapisan lilin (lignin dan kotoran) pada permukaan serat sehingga menghasilkan mechanical interlocking yang lebih baik antara serat dengan matrik poliester. Dengan ikatan yang lebih baik maka komposit tersebut akan mampu menahan beban lentur yang lebih tinggi. Kata kunci: komposit sandwich, serat tapis kelapa, perlakuan NaOH, kekuatan lentur Abstract The use of natural fibers as reinforcement composites is growing. Indonesia as a tropical country produces various types of natural fibers like coconut filter fiber. The purpose of this study is to investigate the effect of alkali treatment of the fiber (5% NaOH. The research material is coconut filter fiber, 157 BQTN unsaturated polyester resin, albasia wood, NaOH and 1% concentration hardener. Skin of composite sandwich consists of the fibers without treatment and 2 hours alkali treatment. Composite sandwich composed of two skins with a core in the middle and production method by hydraulic molding press. Lamina composite as a skin made of 30% volume fraction and 15 mm fiber length Flexural specimens and testing procedures based on ASTM C 393 standards. The results showed that fibers get 2 hours NaOH alkaline treatment resulted in a higher flexural strength. This is because the alkali treatment on coconut filter fiber can clean the wax layer (lignin and dirt) on the surface of the fiber resulting in better mechanical interlocking between the fibers with polyester matrix. Keywords: composite sandwich, coconut filter fiber, NaOH alkaline treatment, flexural strengt

Analisis ketidakpastian pengukuran pada mistar ingsut rentang 0-30 cm

In science of measurement, an error is defined as difference result of measurement and the real value of the measurand.Actually, this real value is never precisely identified; consequently, the error is unknowns as well. In this case, the error canonly be estimated without knowing its real quantity. If a value will be considered as an estimated error, this value should be taken as an uncertainty. Uncertainty of Vernier Calliper determined with Type A and Type B evaluation, then the combinedstandard uncertainty is determined. Vernier Calliper that calibrated with Gauge Block class 1, the maximum uncertainty is ± 3.27 µm in dimension of 12.7 mm, with 95% confidence level