Experimental Study of Microwave Attenuation in a Compartment Fire

In this letter, we show the experimental results of microwave attenuation characteristics for representative communication frequencies (UHF, public safety long-term evolution [PSLTE], LoRa, Wi-Fi, and LTE) in a compartment fire. We used kerosene, lumber, and urethane foam as fuels, which can be easily found in homes, and measured the signal intensity with three antenna heights to investigate the effect of the flame and smoke. In the compartment environment, the ionized particles were the dominant attenuation factor of the signals. Furthermore, measurements revealed that the attenuation depends on frequencies and fuel types. In particular, large attenuation was observed at particular frequencies when burning lumber and urethane foam.

Peningkatan dan Pengendalian Kualitas Produk dengan Menggunakan Metode PDCA (Studi Kasus pada PT. “X”)

PT. 'X' merupakan sebuah perusahaan yang memproduksi lemari es lokal dan berorientasi ekspor. Permasalahan yang ditemukan adalah produk cacat lemari es yang di produksi pada tanggal 1 Agustus - 18 Agustus 2018 terdapat persentase cacat yang cukup tinggi sebesar 59.45% dari sampel total produksi yang dikumpulkan, sehingga produk harus diperbaiki lagi yang mengakibatkan biaya produksi menjadi tinggi. Cacat pada produksi lemari es adalah panel back penyok 15%, urethane foam bocor 68,2%, dan panel back keluar 16,8%. Metode penelitian menggunakan PDCA, tahap plan menentukan masalah dan cacat yang akan diperbaiki, tahap do menentukan usulan tindakan perbaikan yang harus dilakukan, tahap check adalah melakukan pemeriksaan sampel produksi setelah implementasi tindakan perbaikan dan tahap action melakukan evaluasi tindakan perbaikan. Berdasarkan kendali mutu menggunakan metode PDCA di PT. “X” diperoleh tindakan korektif seperti peningkatan kesadaran operator, peningkatan standar kerja, pengaturan lingkungan produksi, pemeliharaan perbaikan mesin u-bander, dan penggantian PU foam dengan A20. Data produksi pada 19 Agustus 2018 - 31 Agustus 2018 ditemukan jumlah cacat akibat urethane foam bocor, panel back penyok, dan panel back keluar sebanyak 219 unit dengan persentase 36,50%. Oleh karena itu tindakan korektif yang dilakukan pada penelitian ini mampu meminimalisasi jumlah cacat sebesar 22,95%.

Comparison of different interlining materials of car seat cover under repeated loadings

In this article, four most commonly used interlining materials (3D spacer fabric, non-woven felt, reticulated foam, and classic Poly-Urethane foam) are tested for comfort and durability. All four layers are tested initially for the air and moisture permeability, then for water vapour permeability under loading and finally tested for compressibility and durability. The repeated loading equivalent to real human pressure was inserted on the samples for 40,000 times to analyse the effect of repeated compression on the interlining materials. This research work gives a very in-depth knowledge of performance of car seat interlining material related to thermophysiological comfort and durability/lifetime.

A Study on Fire Hazards in Multiple Compartments with Lightweight Partition Walls

This paper presents the study of a fire risk to the backside of two miniatures of ISO 9705 2/5 using a lightweight partition for indoor space division and reproduction of the ISO 9705 test. An SGP partition, stud partition, glass wool panel, urethane foam panel, sandwich panel, and glass partition were selected as the test specimens, which are frequently used in construction. According to the ISO 9705 test standard, stabilization was achieved using a measuring device that recorded data before the ignition of a burner and continued recording for 120 s thereafter. After ignition was achieved, the power was increased to 300 kW for 600 s and then reduced to 100 kW for 600 s. The specimens were subsequently observed for 180 s, and the fire risk to the backside and the fire pattern of the wall unit were analyzed. Owing to the amount of heat generated by the ignition source, the maximum temperature of the backside was observed to be 67.7 ℃ for the SGP partition, 55.1 ℃ for the stud partition, 52.4 ℃ for the glass wool panel, 727.4 ℃ for the sandwich panel, 561 ℃ for the urethane foam panel, and 630.5 ℃ for the glass partition. In the cases of the sandwich and urethane foam panels, the explosion of flammable gas occurred by virtue of fusion of the interior materials. The reinforced glass was fractured owing to the temperature difference between the heat- and nonheat-responsive parts. Ultimately, the fire risk to the nearby section room was deemed to be high.

Improvement of Flame-Retardant Performance of Polyurethane Foam Coated with Water Glass

In this study, water glass was applied as a coating material to a rigid polyurethane foam to improve the flame-retardant properties of the foam. The heat release rate of the cone calorimeter of the urethane foam, in which the inorganic water-glass coating layer was applied, decreased rapidly. The water glass coated on the polyurethane surface formed a glassy foam by foaming with water, which did not escape during the vitrification reaction when the foam or glass was heated. The glassy foam formed on the polyurethane foam became a fire-resistant insulation layer that inhibited the combustion of the polyurethane foam for more than 10 min. Water glass was found to improve the flame-retardant properties of the rigid polyurethane foam.