System dynamics modeling for evaluating the profits of the upstream supply chain of Citronella Oil

Citronella oil is an aromatic oil obtained through the distillation of citronella stems or leaves. In Indonesia, the distillation process is predominantly carried out by small to medium-sized enterprises. Enhancing the reliability of the citronella oil supply chain has the potential to increase the profits of farmers and distillers. However, farmers and distillers in Indonesia face the challenge of fluctuating prices for citronella oil, leading to a decline in profits. This research aims to model the upstream supply chain system of citronella essential oil. The study has identified the key stakeholders involved in the citronella oil supply chain through a causal loop diagram, employing a system dynamics approach. The recommended scenario involves adding an essential oil processing industry as an additional participant in the citronella oil supply chain network. The simulation model's results over the period from 2023 to 2027 indicate an increase in profits for each stakeholder in the upstream citronella oil supply chain. The total profit of the upstream supply chain amounts to USD 2,284,829, representing a 52.3% increase

Effect of heat treatment and cryogenics on hardness of ductile cast iron microstructure (FCD­50)

The results of researches of possibilities of increasing the mechanical properties of pig iron with ball-bearing graphite of brand FCD-50 by the combined heat treatment are described. The scheme of multistage heat treatment, the characteristic feature of which is the operation of cooling in liquid nitrogen, is proposed. The use of such a scheme allows for increased HRC hardness characteristics. The study of the microstructure of cast iron treated with this scheme has proved the efficiency of the cryogenic heat treatment stage and determined its rational regimes.To match or approximate the properties of steel, the mechanical properties of this ductile cast iron 50 (FCD-‎‎50) must be ‎enhanced by methods such as ACTDI (austemper cryogenic and temper Ductile Iron). In this procedure, the FCD-50 specimen is inserted into the electric kitchen heater at 350 °C ‎‎(room temperature), heated to 600 °C and held at this temperature for 45 minutes. Next, the ‎specimen is heated to 900 °C and held at this temperature for 1 hour ‎‎(temperature austenisation). Then, the specimen is placed in furnace 2 at 3,000 °C for 45 minutes ‎‎(austempering process). The specimen subsequently is cooled in ‎liquid nitrogen. In this study, additional specimens were obtained for hardness and ‎microstructure tests. The as-cast test yielded a ‎hardness value of 18.39 HRC. In the hardness test for the ACTDI process, 12 ‎hours of submersion yielded the highest hardness result of 24.25 HRC. ‎In terms of the changes in microstructure after soaking changes, the amount of perlite present in the specimen was greater than that of ferrite, and the arrangement of graphite ‎nodules was better than that of the as-cast material.‎Описаны результаты исследований возможностей повышения механических свойств чугунов с шаровидним графитом марки FCD-50 путем комбинированной термической обработки. Предложена схема многоступенчатой термической обработки, характерной особенностью которой является операция охлаждения в жидком азоте. Использование такой схемы позволяет получить повышенные характеристики твердости HRC. Исследованием микроструктуры чугунов, обработанных по такой схеме, доказана эффективность криогенного этапа термической обработки и определены ее рациональные режимыОписано результати досліджень можливостей підвищення механічних властивостей чавунів з шаровідним графітом марки FCD-50 шляхом комбінованої термічної обробки. Запропоновано схему багатоступінчастої термічної обробки, характерною особливістю якої є операція охолодження у рідкому азоті. Використання такої схеми дозволяє отримати підвищені характеристики твердості HRC. Дослідженням мікроструктури чавунів, оброблених за такою схемою, доведена ефективність кріогенного етапу термічної обробки та визначено її раціональні режим