Effect of Solidifying Structure on Centerline Segregation of S50C Steel Produced by Compact Strip Production

Medium-high carbon steels having a high quality are widely used in China. It is advantageous to produce high value-added hot-rolled plates with the crystal refined and chemical composition homogenized in the casting slabs. However, element segregation occurs easily during high-medium carbon steels’ production. Generally, the centerline segregation is improved by enlarging the equiaxed zone with low-superheat casting and electromagnetic stirring (EMS). Studies were conducted on centerline segregation of S50C steel slabs with a thickness of 52 mm produced by the compact strip production (CSP) process in China without EMS equipped. By sampling along the width at different position, the secondary dendrite arm spacing (SDAS) was measured after etching and picture processing, based on which the cooling rate was calculated. It was found that the cooling rate increased from the center to the surfaces of the slabs ranging in 1~20 K/s, 10 times faster than that of a conventional process. The faster cooling rate led to a refined solidifying structure and columnar dendrite through the center of the slabs. The SDAS tended to increase from surfaces to the center, ranging only 32~120 μm smaller than that of a conventional process in 100~300 μm, indicating a finer solidifying structure by the CSP process. Results by EPMA indicated that elements C, Si, and Mn distribute in dispersed spots, increasing towards the center, and the centerline segregation changed in a narrow range: for C mainly in 1.0~1.1, Si in 0.98~1.08, Mn in 0.96~1.02, respectively, meaning a more chemical homogenization than that of thick slabs. Elements’ segregation originated from solute redistribution between solid and liquid. According to thermodynamic calculation, δ region of S50C is so narrow that the solute redistribution mainly occurred between γ-Fe and liquid during solidification. As the equilibrium partition coefficient of element C was the smallest, it was easy for C to be rejected to the residual liquid in the inter-dendritic space, leading to obvious segregation, relatively. Besides, as a result of high-cooling intensity, the solidifying structure became so fine that the Fourier number increased and the volume of the residual liquid decreased, making centerline segregation alleviated effectively both in volume and degree. Although bulging was observed during the industrial experiment, the centerline segregation was still inhibited obviously as the refining solidifying structure with permeability ranged only in 0.1~2.3 μm2 from the surfaces to centerline, which showed a good resistance on the residual flow towards the centerline.

Removal of Heavy Metal Mercury (Hg) Liquid Waste through Electrolysis Method in Paya Ateuk Village, Pasie Raja District, South Aceh

Electrolysis is one of the methods used to remove heavy metal mercury (Hg). The electrolysis process is carried out on residual liquid waste from gold processing by utilizing chemical reactions through electrodes immersed in an electrolyte solution. This research method is experimental. We conducted laboratory tests to see the electrolysis process on the residual liquid waste from gold processing in a 10-liter container. We took samples from 10 different containers, 1 liter each from each tub. Sampling time was carried out in the morning, afternoon, and evening. The results showed a significant decrease in mercury (Hg) levels up to 1.30% with 12 volts of electricity for 100 minutes. In contrast, the lowest decrease occurred in the electric current of 3.3 volts within 25 minutes. We use the electrolysis method. This heavy metal removal technique can be applied and managed properly by the community and local government to minimize heavy metal pollution such as mercury in the surrounding environment due to waste from the community's traditional gold processing.

Understanding the Effect of Stepwise Irrigation on Liquid Holdup and Hysteresis Behavior of Unsaturated Ore Heap

Liquid is a crucial medium to contain soluble oxygen, valuable metal ions, and bacteria in unsaturated heap leaching. Liquid retention behavior is the first critical issue to be considered to efficiently extract low-grade minerals or wastes. In this study, the residual liquid holdup of an unsaturated packed bed was quantitatively discussed by liquid holdup (θ), residual liquid holdup (θresidual), relative liquid holdup (θ’), and relative porosity (n*) using the designed measuring device. The detailed liquid holdup and the hysteresis behavior under stepwise irrigation are indicated and discussed herein. The results show that relative porosity of the packed bed was negatively related to particle size, and intra-particle porosity was more developed in the −4.0 + 2.0 mm packed bed. The higher liquid retention of the unsaturated packed bed could be obtained by using stepwise irrigation (incrementally improved from 0.001 to 0.1 mm/s) instead of uniform irrigation (0.1 mm/s). It could be explained in that some of the immobile liquid could not flow out of the unsaturated packed bed, and this historical irrigation could have accelerated formation of flow paths. The θ was sensitive to superficial flow rate (or irrigation rate) in that it obviously increased if a higher superficial flow rate (u) was introduced, however, the θresidual was commonly affected by n* and θ’. Moreover, the liquid hysteresis easily performed under stepwise irrigation condition, where θ and θresidual were larger at u of the decreasing flow rate stage (DFRS) instead of u of the increasing flow rate stage (IFRS). These findings effectively quantify the liquid retention and the hysteresis behavior of ore heap, and the stepwise irrigation provides potential possibility to adjust liquid retention conditions.

SDS-PAGE gel electrophoresis v2

SDS-PAGE gel electrophoresis protocol for analyzing samples from plant leaf tissue via immunofluorescence. In this protocol no Coomassie blue is added to samples, the reason is that this interferes with the fluorescent signal during immunoblot. Instead, samples have already been prepared in Laemmli buffer (minus coomassie, protein extraction procedure), the leading edge of samples can be visualized due to the presence of chlorophyll. Note - When using 15 well, 0.75 mm comb, try to limit the volume loaded to 10 μL to minimize the risk of spillover of protein between wells. - Ensure that accurate volume is pipetted by removing sample stuck to the outside of the pipette tip by wiping the tip on the rim of the sample tube to remove any residual liquid. Literature: http://www.bio-rad.com/webroot/web/pdf/lsr/literature/Bulletin_6040.pdfhttps://www.bio-rad.com/webroot/web/pdf/lsr/literature/10026447.pdf

PERENCANAAN ARENA GOKAR DAN RC CARS INDOOR DI PULAU KUMALA TENGGARONG PENEKANAN PADA UTILITAS

Lots of entertainment and game facilities that are no longer active on Kumala Tenggarong Island have caused a decline in the number of visitors each year, one of the facilities is outdoor Gokart Arena which currently in poor condition. The solution to increase visitor attraction and reintroduce Karting to the public is by planning Gokart Arena and RC Cars Indoor Arena as entertainment and game-themed racing facilities on Kumala Tenggarong Island. However Gokart racing activities have a negative impact on the environment such as residual liquid (oil) and solid waste (iron frame, etc.), cause noise and pollution and require good lighting for the safety of racers, therefore building design is emphasized on utilities, especially wastewater, natural lighting and natural ventilation for sustainability and comfort of buildings and the environment can be maintained properly. The application of the industrialist architectural style to the facade and interior layout through material exposure elements creates a unique character in the building with a rough and masculine look.

Characteristics and Chemical Compounds Liquid Smoke of Mangrove Stem Bark Waste from Charcoal Industry

In Batu Ampar, the charcoal industry, West Kalimantan, used Rhizophora sp. mangrove to produce liquid acid with mangrove stem bark waste as a side product. Pyrolysis of liquid smoke of mangrove stem bark waste at a temperature of 4000C for 6 hours resulted in a yield of 33.97% with pH, specific gravity, and color were 2.8, 1.004, and brown, respectively. Analysis of GC-MS showed that liquid smoke without distillation has 16 chemical compounds where the main components were acetone (12.32%), acetic acid (11.62%), 2-furancarboxaldehyde (26.72%), 5-methyl furfural (13.87%) and phenol, 2-methoxy (13.31%). Furthermore, this liquid smoke is distilled at 1000C to produces residual liquid smoke and distillate liquid smoke. The residual liquid smoke resulted in a yield of 95.8% with characteristics of pH, specific gravity, and color were the lowest 2.73, 1.004, and dark brown, respectively. The liquid smoke residue contained 12 chemical compounds where the main components were butanal, 3-hydroxy- (17.46%), acetone (17.15%), acetic acid (32.27 %), and 2-furancarboxaldehyde (13.28%). Distillate liquid smoke resulted in a yield of 4.2% with pH, specific gravity, and color characteristics, which were 2.8, 1.001, and yellow, respectively. This liquid smoke contained nine chemical compounds, with the main components were ethyl ester (26.69%) and ethylene glycol (64.70%). Based on the GC-MS data, the liquid smoke from mangrove leather waste did not contain poly-aromatic hydrocarbon (PAH) or benzopyrene compounds.

Peningkatan Produktivitas Pupuk Kompos Bioaktivator dengan Bahan Baku Limbah Organik Rumah Tangga

Pertanian yang ramah lingkungan masih menjadi prioritas bagi pemerintah daerah dalam pembangunan berkelanjutan karena diharapkan dapat meningkatkan dan mempertahankan produktivitas tinggi dalam bidang pertanian. Pengabdian ini dilakukan dengan tujuan untuk mewujudkan pertanian ramah lingkungan dengan memanfaatkan limbah organik rumah tangga sebagai bahan baku pembuatan kompos dengan Biokativator. Sasaran kegiatan dalam pengabdian ini adalah Kelompok Wanita Tani (KWT) Nila 4A, KWT Nila 6E dan KWT Lahan Hijau di RT.4 RW.01 Kelurahan Sumber Jaya Kecamatan Kampung Melayu Kota Bengkulu dengan jumlah sasaran sebanyak 45 orang. Metode yang digunakan dalam pengabdian ini terdiri dari 4 tahapan yaitu, tahap observasi, tahap penyuluhan, tahap monitoring, dan tahap evaluasi. Hasilnya adalah pupuk kompos yang dihasilkan cukup bagus, tidak ada ulat atau belatung, serta tidak terlalu bau., pupuk kompos dengan karakteristik demikian sangat cocok untuk diaplikasikan pada pertanian. Selain pupuk daun, dari kegiatan ini juga dihasilkan pupuk cair organik yang merupakan sisa cairan dari proses pembuatan pupuk kompos dengan bioaktivator. Setelah kegiatan ini KWT Nila 4A, KWT Nila 6E dan KWT Lahan Hijau di RT.4 RW.01 Kelurahan Sumber Jaya Kecamatan Kampung Melayu Kota Bengkulu diharapkan dapat membuat kompos bioaktivator dengan kualitas bagus dan berdaya jual tinggi.Kata Kunci: bioaktivator; limbah organik rumah tangga; pupuk kompos. Increasing the Productivity of Bioactivator Compost with Organic Household Waste Raw MaterialsABSTRACTEnvironmentally friendly agriculture is still a priority for local governments in sustainable development because it is expected to increase and maintain high productivity in agriculture. This service was carried out with the aim of realizing environmentally friendly agriculture by utilizing household organic waste as raw material for composting with biocativators. The targets of this service are the Women Farmers Group (KWT) Nila 4A, KWT Nila 6E and KWT Green Land in RT.4 RW.01 Kelurahan Sumber Jaya Sub-district Kampung Melayu Bengkulu City with a total target of 45 people. The method used in this service consists of 4 stages, namely, the observation stage, the counseling stage, the monitoring stage, and the evaluation stage. The result is that the compost produced is quite good, there are no caterpillars or maggots, and does not smell too much. Compost with these characteristics is very suitable for application in agriculture. Apart from foliar fertilizers, this activity also produces organic liquid fertilizer, which is the residual liquid from the compost-making process using a bioactivator. After this activity, KWT Nila 4A, KWT Nila 6E and KWT Green Land at RT.4 RW.01 Kelurahan Sumber Jaya Sub-district Kampung Melayu City Bengkulu City are expected to be able to make bioactivator compost with good quality and high selling power.Keywords: bioactivator; household organic waste; compost.