Hydrodynamics of Fluid Flow in Fixed-Beds Composed of Sand Particles and Hollow Fiber Membrane Pipes

ABSTRAK Kompos artifisial yang dibuat dari bahan polimer baru-baru ini menarik perhatian peneliti sebagai pupuk yang tahan lama dan dapat meningkatkan produktivitas tanaman tanpa menimbulkan dampak yang besar pada lingkungan. Dalam penelitian ini, pipa membran hollow fiber (HFMP) yang terbuat dari bahan polipropilen dan pasir kuarsa, masing-masing digunakan sebagai model kompos artifisial dan partikel tanah. Hidrodinamika unggun yang terdiri dari HFMP dan pasir kuarsa diteliti dengan menggunakan metode falling-head. Hasil percobaan menunjukkan bahwa unggun yang ditambahkan HFMP mengalami peningkatan porositas unggun. Unggun dengan fraksi HFMP yang lebih tinggi menunjukkan kemampuan menahan air yang lebih rendah, yang mengindikasikan kemampuan yang buruk dari bahan polipropilen dalam menahan molekul air. Sebaliknya, permeabilitas yang lebih tinggi pada unggun yang ditambahkan HFMP menunjukkan aliran cairan yang lebih baik. Studi ini mengungkap potensi kompos artifisial yang dapat diterapkan dalam teknologi pertanian berkelanjutan. Kata kunci: Hidrodinamika, kapasitas menahan air, porositas, permeabilitas, kompos buatan ABSTRACT Artificial compost fabricated from polymer materials has recently attracted considerable interest as a highly durable fertilizer that could enhance plant productivity without harming the environment. In this study, polypropylene hollow fiber membrane pipes (HFMP) and quartz sand particles were employed as models of the artificial compost and soil particles, respectively. The hydrodynamics of various volumetric ratios of beds composed of the HFMP and the quartz sand were investigated using a falling-head technique. The results show that the bed supplemented with the HFMP demonstrated enhanced bed porosity. The bed with a higher HFMP fraction exhibited slightly less water-holding capacity, which suggests the poor ability of the polypropylene material to retain water molecules. On the contrary, the higher permeability of the bed amended with the HFMP indicates improved water flow. This study unfolds the potential of artificial compost that can be implemented in sustainable agricultural technology. Keywords: Hydrodynamics, water-holding capacity, porosity, permeability, artificial compost

Floating synthetic filtering device development for turbidity value reduction of water in Eshkakon reservoir

This paper presents multifactorial studies to solve the improving water quality problem where effective filtering devices development is relevant. Intake filters perform primary treatment retain water suspension and debris of anthropogenic origin. Water analysis monitoring of the Eshkakon reservoir has been presented, as a result there is a need to use a filtration device to reduce its turbidity. A comparative analysis of material, construction and operating costs of various types of water intakes is given and the most economical and prospective one, composed of soft floating filtering devices made of synthetic fabrics, is identified. The main purpose of the device is to reduce “mud load”, mechanical pre-treatment of fresh water until entering a water treatment plant (WTP), water purification from plankton and suspended particles. The main element of the device is a filter wall made of flexible polypropylene material, which makes selective water intake. Advantages of the device include flexibility, high short-term and long-term strength, rot proofing; compliance of the filter design with effective fish protection devices; economic effect of advent of technology is to reduce investment in its manufacture, material consumption and labor costs in operational cycle.

Investigation of future 3D printed brace design parameters: evaluation of mechanical properties and prototype outcomes

Aim: Spinal brace wear time affects treatment effectiveness of adolescent idiopathic scoliosis but remains challenging with the brace’s bulkiness. This study aims to determine the appropriate material and thickness to improve wear comfort. Materials & methods: Thirty-one specimens were tested with 13 ULTEM1010 and 13 Nylon12 potential materials and 5 standard polypropylene material in 2.5, 3.25 and 4 mm thicknesses to evaluate mechanical properties. Donning tests of ULTEM1010 and Nylon12 printed braces were conducted. Results: Nylon12 with 2.5–3.25 mm thickness had higher flexibility and the closest mechanical characteristics as 4-mm thick polypropylene. ULTEM1010 brace fractured after 615-times and Nylon12 brace handled 2920-times of opening and closing. Conclusion: Nylon12, 2.5–3.25 mm are appropriate design parameters. Further clinical study can validate long term brace effectiveness.

Surface modification of nettle fibers by grafting to improve oil sorption capacity

In this study, an attempt was made to enhance the oil sorption capacity of nettle fibers by grafting of butyl acrylate. Box–Behnken experimental design was used to study the effect of parameters such as reaction time, reaction temperature and monomer concentration-to-fiber ratio on graft add-on (%) and oil sorption capacity. At 4-h reaction time, 70℃ temperature and 2% monomer concentration-to-fiber ratio, highest graft add-on (%) and oil sorption were attained. Maximum oil sorption capacity of grafted nettle was 36.60 g/g and 25.56 g/g against crude oil and vegetable oil, respectively. Grafted nettle fibers were also subjected to characterization by Fourier-transform infrared spectroscopy, scanning electron microscopy and contact angle tests. Reusability test results showed that grafted nettle exhibited better oil sorption capacity than unmodified nettle even after seven sorption–desorption cycles. It is also observed that the oil sorption capacity of grafted nettle was higher than that of commercial polypropylene material. Based on these results, it is concluded that functionalized nettle prepared by grafting technique can be a potential material for oil spill treatment.