Recycled Polyethylene Modified Asphalt Binders and Mixtures: Performance Characteristics and Environmental Impact

This study addresses the effects of recycled polyethylene (RPE) on the performances of both asphalt binders and asphalt mixtures. Whether using RPE in an asphalt mixture might leach harmful chemicals into rainwater or melted snow was also determined. Two processes, wet and dry, were used to formulate the RPE modified asphalt binders and mixtures. In the wet process, RPE was added to asphalt binder. In the dry process, it was added to heated aggregates. RPE from two sources and PG 64-22 virgin asphalt binders from two sources were used in this study. In conclusion, RPE improved the rutting resistance of the asphalt binders and asphalt mixtures. However, it had adverse effects on their resistance to intermediate-temperature and non-load associated cracking. The dry process could produce a mixture with a higher RPE dosage compared with the wet process using one virgin asphalt binder but not the other; thus, the virgin asphalt binder source was a significant factor for the dry process. Based on an embryotoxicity test, it was found that RPE can be used by the asphalt paving industry without creating any significant environmental risks.

Static puncture resistance characteristics with various indenter nose shape geometry perforation of shear thickening fluid impregnated polypropylene fabric for soft armour application

At present, puncture resistance and rheological performance of shear thickening fluid (STF) is an essential design requirement for a soft armour material (target sample). The target sample is prepared with a dip and dry process of STF impregnated woven polypropylene (PP) fabric. These samples were tested and compared with neat PP fabric. The penetration depth of target samples is highly sensitive to the coefficient of friction between the indenter’s nose shape geometry and the target sample. The STF is prepared by mechanical dispersion of synthesized microsphere silica microparticles at a volume fraction of 57% in polyethylene glycol (400 g/mol). The rheological response indicates that the prepared concentration of silica microparticles in the STF suspension is observed to have a better shear thickening effect. The viscosity of suspension is highly sensitive to silica aspect ratio, volume fraction and particle size distribution in this work. Tensile tests along with puncture resistance with different indenter nose shapes geometry (hemispherical, elliptical, flat and conical) have been performed in the present study. Results indicate that the energy absorption is more with the hemispherical indenter and less with that of the conical indenter, which is attributed to the minimum surface area of contact as compared to all other indenters. A total of 16 number of fabricated target samples with various coating thicknesses of STF impregnated fabrics achieved the desired tensile strength, modulus and puncture resistance.

Identification of antioxidant components of Gayo Arabica Coffee Cascara using the GC-MS method

Approximately half of the coffee will become by-product in coffee processing. This by-product needs a special focus because of its content can be pollutant for nature. One of the coffee by product that underutilized is cascara, composed by pulp and husk. The major by-product of dry process is husk whereas pulp is the major by-product from wet process. Nowadays, there are various ways to utilize coffee by-product. Previous studies have shown that coffee has a potent antioxidant activity which can be a solution in dermatology problem. This research aims to identify the antioxidant component of coffee arabica husk and pulp of Gayo, Aceh Tengah, Aceh using GC-MS method. One of the compounds that identified in both coffee husk and pulp is caffeine. Caffeine is a potential natural antioxidant and it also has anticellulite effect to skin. The other compounds found in coffee husk and pulp also have benefit in dermatology. We conclude that coffee arabica husk and pulp can be a potential natural source to eradicate dermatologic problem.

A Study on the Development of Carbon Fiber with Electromagnetic Wave Shielding Performance and Sizing Removal State Measurement Algorithm Using Image Processing

In this paper, nickel-plated carbon fiber was fabricated by a dry process method to improve electromagnetic wave shielding performance. In general, carbon fiber is wrapped in a polymer type in manufacturing and is used after removing the sizing in the pretreatment step for dry coating. The existing sizing removal method was used by removing only with a solution or only with compressed air. In this paper, the method of solution and compressed air (hybrid) was added. The state in which the sizing was removed was determined only by the know-how of the experienced person, and in this paper, it is proposed to represent the numerical value by applying the image processing surface analysis technique. As a result, it was possible to numerically indicate that the hybrid method was excellent among the sizing removal methods and it was possible to manufacture the nickel-plated carbon fibers (30 μm, 40 μm, and 100 μm) by a roll-to-roll sputtering method on the sizing-removed spreading carbon fiber roll. The electromagnetic wave shielding performance of 100 nickel-coated carbon fiber measured by the Korea Testing Laboratory showed the highest electromagnetic wave shielding performance from 66.7 (dB) to 73.2 (dB). This is similar to the electromagnetic wave shielding rate of copper, so it can be used as a cable for EV/HEV vehicles, and it is expected to have a great effect of improving the bending characteristics and disconnection phenomenon and improving the lifespan compared to the existing copper wire.

Controlling Factors of the Particle Size of Spherical Silica Synthesized by Wet and Dry Processes

We clarified the controlling factors of the particle size of the amorphous silica synthesized by wet and dry processes. In the wet process using methyl-trimethoxy-silane as a starting monomer, the obtained particle size can be easily controlled by changing the reaction time appropriately. However, to obtain larger particles, a relatively long time is needed. After the condensation reaction was conducted for 50h, the silica particles (D50: 3μm) were synthesized by calcination at 550oC in air. To synthesize larger silica particles, we used silica-seed particles (8μm) to obtain very large spherical silica particles (D50: 20μm). Thus, although the wet process needs a relatively long reaction time, it is very useful for synthesizing spherical silica particles with a wide range of particle size. In the dry process, we used methyl-trimethoxy-silane (MTMS), tetra-ethoxy-silane (TEOS), and octamethyl-cyclotetrasiloxane (OMCTSO) as the starting materials. In this process, the size of the silica particles was dominated by the molecular structure of the monomer, in particular, the number of silicon atoms contained in the monomer and the bulkiness of the substituent group. The largest silica particles were synthesized from OMCTSO, which contains the largest number of silicon atoms.

Pengaruh Penambahan Limbah Plastik Low Density Polyethylene Terhadap Karakteristik Campuran Laston AC-WC

Permasalahan sampah plastik saat ini telah menjadi salah satu konsentrasi dunia. Upaya pengurangan dan pencegahan telah banyak dilakukan, namun secara umum hasil yang didapat tidak sebanding dengan pertumbuhan penggunaan plastik yang terus meningkat khususnya plastik yang tidak terkelola dengan baik. Salah satu upaya yang dilakukan adalah pemanfaatan limbah plastik sebagai bahan tambah campuran beraspal panas Laston AC-WC yang disebut modifikasi. Tujuan penelitian ini adalah untuk mengetahui bagaimana pengaruh penambahan limbah plastik jenis Low Density Polyethylene (LDPE) terhadap karakteristik Marshall Laston AC-WC. Pengujian yang dilakukan antara lain pengujian agregat, pengujian aspal, pengujian plastik, dan pengujian Marshall. Perancangan campuran dilakukan dengan cara kering (dry process) menggunakan variasi kadar plastik sebesar 0%, 4,5%, 5%, dan 5,5% yang masing-masing memakai 5 kadar aspal yaitu 5%, 5,5%, 6%, 6,5%, dan 7% dengan masing-masing 3 benda uji, sehingga total ada 75 benda uji. Hasil uji Marshall diperoleh KAO sebesear 6,5% dengan variasi kadar plastik sebesar 5,5%, diperoleh stabilitas 2167,40 kg, Flow 3,8 mm, VIM 3,94%, VMA 15,95%, VFA/VFB 77,12%, dan MQ 570,37 kg/mm. Sehingga penambahan limbah plastik jenis LDPE memenuhi (Spesifikasi Umum Bina Marga, 2018).

Pengaruh Penambahan Plastik LDPE Pada Campuran Aspal Beton Lapis AC-BC

Pertumbuhan volume lalu lintas yang meningkat memberikan dampak terhadap permintaan akan pembangunan struktur perkerasan jalan dan penggunaan material yang digunakan. Oleh karena itu, diperlukan suatu material yang dapat membantu melapisi bahan agregat selain aspal agar dapat mengurangi pengaruh tersebut, contohnya bahan polimer atau plastik. Salah satu upaya yang dapat dilakukan yaitu dengan dilakukan modifikasi pengaruh penambahan plastik Low Density Poly Ethylene (LDPE) sebagai bahan tambahan dalam campuran lapis aspal beton AC-BC (Asphalt Concrete-Binder Course). Tujuan dari penelitian ini adalah untuk mengetahui bagaimana pengaruh penambahan plastik jenis Low Density Poly Ethylene (LDPE) sebagai bahan tambah campuran beraspal panas AC-BC terhadap karakteristik Marshall. Pengujian yang dilakukan antara lain pengujian agregat, pengujian aspal, pengujian plastik, dan pengujian Marshall. Perancangan campuran dilakukan dengan cara kering (dry process) menggunakan variasi kadar plastik sebesar 0%, 2%, 3%, dan 4% dengan masing-masing kadar aspal yaitu 4,5%, 5%, 5,5%, 6,0%, dan 6,5%, jumlah benda uji yang dibuat yaitu 75 benda uji. Dari hasil uji Marshall diperoleh nilai KAO sebesar 6,5% dengan variasi kadar plastik LDPE 3%. Dengan nilai stabilitas sebesar 1878,40 kg, nilai flow sebesar 3,81 mm, nilai MQ sebesar 472,5 kg/mm, nilai VFB/VFA sebesar 72,55 %, nilai VIM sebesar 4,29 %, dan nilai VMA sebesar 17,74%.

Pemetaan Atribut Sensori Kopi Kobura Berdasarkan Perbedaan Cara Panen dan Pengolahan di Tingkat Petani

<p><em>In general, Kobura coffee farmers in South Ogan Komering Ulu (OKU) harvest coffee with the criteria of red fruit and a mixture of red and green, while the processing method is a dry process. However, the sensory attributes of these activities are not yet known. This study aims to map the sensory qualities of Kobura coffee at the farmer level based on differences in harvesting and processing methods. The research was carried out in Banding Agung District, South OKU Regency, and the Coffee and Cocoa Bioindustry Laboratory, Balittri, Sukabumi, from March to December 2019. The design used was a completely randomized design with 3 treatment factors and two replications. The first factor was three clones of Kobura coffee (Kobura 1, 2, 3), the second factor was two harvesting methods (red and mix of red + green fruit), and the third factor is two processing methods (dry and wet). The variable observed were the sensory attributes analyzed by multivariate analysis of variance, principal component analysis, cluster analysis, and path analysis. The results showed that the harvesting and processing methods of Kobura coffee at the farmer level in South OKU did not significantly affect the sensory. Furthermore, each cluster's harvesting and processing methods were evenly distributed because the proportion between red and green fruit was not clearly identified in the mixed fruit harvest. Superior genetic and optimal altitude factors make Kobura coffee categorized into Fine Robusta with a final score of 81.13-85.75. The final score is directly and dominantly influenced by mouthfeel (body), flavor, overall, and fragrance, respectively.</em></p>

From Plantation to Cup: Changes in Bioactive Compounds during Coffee Processing

Coffee is consumed not just for its flavor, but also for its health advantages. The quality of coffee beverages is affected by a number of elements and a series of processes, including: the environment, cultivation, post-harvest, fermentation, storage, roasting, and brewing to produce a cup of coffee. The chemical components of coffee beans alter throughout this procedure. The purpose of this article is to present information about changes in chemical components and bioactive compounds in coffee during preharvest and postharvest. The selection of the appropriate cherry maturity level is the first step in the coffee manufacturing process. The coffee cherry has specific flavor-precursor components and other chemical components that become raw materials in the fermentation process. During the fermentation process, there are not many changes in the phenolic or other bioactive components of coffee. Metabolites fermented by microbes diffuse into the seeds, which improves their quality. A germination process occurs during wet processing, which increases the quantity of amino acids, while the dry process induces an increase in non-protein amino acid γ-aminobutyric acid (GABA). In the roasting process, there is a change in the aroma precursors from the phenolic compounds, especially chlorogenic acid, amino acids, and sugars found in coffee beans, to produce a distinctive coffee taste.