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Indonesia has an opportunity in developing the coffee processing industry, because apart from having a large market, it is also supported by potential raw materials. Therefore, strategic efforts are needed, such as downstream in order to increase added value and increase production capacity (Kemenperin, 2019). To determine the quality of the coffee can be seen based on two tests namely physical quality testing, and taste. Moisture value of coffee beans the maximum is 12.5%. One form of control is an increase in coffee processing technology, namely roasting machines (Maulid et al, 2021). This research focuses on forced convection hot air flow by a blower whose speed is engineered using the help of a dimmer speed controller to obtain optimal heat and mass transfer results by experimentally varying airflow and heat transfer then obtaining optimal speed and temperature values. Temperature also affects the value of the forced convection coefficient. The largest convection coefficient is found in the variation of the highest temperature value test, namely 297.5 ᵒC with a value of 43.66 W/m2 ᵒC. The lowest convection coefficient value lies in the experimental variation with an air flow velocity value of 11.4 m/s at a temperature of 297.5 ᵒC with a convection coefficient value of 28.38 43.66 W/m2 ᵒC. The convection heat transfer value (Q) will increase when the flame temperature (T) and air flow velocity increase (v). The greatest electric power will increase when the air flow velocity increases with a low flame temperature value. Effect of airflow velocity (v) and flame temperature (T) simultaneously on the final roasting temperature of 87.5%. [ABSTRACT FROM AUTHOR]

Utilization of geothermal energy is still dominated by indirect use for electricity generation, beside geothermal energy can also be used for direct application. Direct use is mostly using a low enthalpy geothermal resources (<150°C), one of the applications of low enthalpy geothermal energy is for drying process. Drying is a post-harvest method that aims to improve the quality of agricultural products by removing some of the water to an agreed an d safe limit, while microorganisms unable to grow and multiply. Coffee is one of the important commodity which has an important role in economic sector in Indonesia. In this study, the Computational Fluid Dynamics (CFD) method is used to determine and predict the drying chamber's temperature and air flow distribution patterns. The simulation process is carried out by varying the thermosiphon heat temperature (50, 60, and 70 °C) and the air inlet velocity (0.2, 0.4, and 0.6 m/s). The simulation results show the uniformity of temperature in the drying chamber, with the highest drying air temperature is 57.72°C, where the air temperature is influenced by the thermal temperature of the thermosiphon and the large air flow velocity. Based on the simulation conditions, the highest amount of heat needed in the drying process is 118.79 kJ/kg at temperature condition of 50°C with velocity 0.6 m/s and the lowest is 117.41 kJ/kg. [ABSTRACT FROM AUTHOR]

Roasting is the stage where coffee beans develop specific organoleptic properties in terms of taste, aroma, and color. The roasting process is a process that depends on temperature and time where the coffee beans undergo a series of reactions that cause some changes in their chemical composition. These two parameters will determine how high the quality of the coffee beans produced even though they come from the same type of coffee beans. From a technological point of view, roasting is a process that originates from the forced flow of electrically produced hot gases to roast green coffee beans into mature coffee. In Indonesia, local clay materials have long been used to create various containers for combustion at high temperatures, including coffee roasting. The weakness of clay walls as a heat conductor is the length of roasting time but this material is to produce a distinctive aroma and taste. To overcome this, innovation is needed in the coffee roasting process. Therefore, the purpose of this study was to determine the heat transfer process in a roasting machine with a modified clay-walled combustion chamber using a forced flow system (semi hot air flow). Based on the experimental results, it was found that the heat formed through the hot air flow was higher in temperature than the heat from the combustion chamber walls. This happens because there is a layer of clay 10 mm thick and clay is a lower heat conductor than aluminum. But in terms of aroma, taste and color of the product, the combustion chamber with a layer of clay can produce better coffee characteristics than aluminum. [ABSTRACT FROM AUTHOR]

This work aims to conduct the numerical modeling of airflow distribution in the HVAC unit room for the high-speed train passenger coach. A cubical space measuring 2800 mm x 1900 mm x 600 mm, with solid geometry boundaries of enclosed walls, compartments, and system components, was discretized into the computational domain. Pressure boundary conditions were used as the parameters of airflow inlet and outlet. Heat exchanger and filter components were modeled as porous media, and flow was assumed as ideal gas fluid and taking k-epsilon turbulence model as the governing equation for flow physics transport and transient as well. Some aspects of the availability of unit space sizes, geometry and dimension of system components, space configuration for the sides of fresh, return, supply, and exhaust air ducts, as well as work parameters according to the results of calculations, were taken as input parameters in modeling. Based on the analysis of the results of the HVAC unit space configuration modeling, it was found that the placement of the air sides in the mixing, supply, and condenser compartments, according to the work parameters that meet the design, greatly determined the characteristics of fluid flow, especially pressure distribution and flow recirculation. [ABSTRACT FROM AUTHOR]

One of main imported food commodity in Indosesia is Enokitake mushroom (Flammulina velutipes). This tasty mushroom with high nutrition value, not evenly distributed among the country. Enokitake mushroom in Indonesia only found in modern market such department store with expensive price. Enokitake mushroom is winter mushroom which can only grow in subtropical country such Japan, therefore in Indonesia, Enokitake mushroom rarely found as nobody could cultivating. As consequences, this study aims to know how to cultivate Enokitake mushroom (Flammulina velutipes) in vitro at Greenhouse FMIPA UM and to develop these cultivation as entrepreneur and learning center in Indonesia. The cultivation done by making PDA as media, F1 in vitro cultivation, and F2 cultivation. F2 cultivation using baglog as the media. The result of F1cultivation not optimal due to contamination by other microorganism. Enokitake mushroom cultivation as entrepreneur and learning center in Greenhouse FMIPA UM can not be continued to F2 cultivation. The final result of this research is new procedure to cultivate F1 Enoktake (Flammulina velutipes) that will done in Laminar Air Flow and adding chloramphinecol as anti-biotic. [ABSTRACT FROM AUTHOR]

Indonesia needs the socialization of agricultural technology so that product quality is guaranteed. Indonesia also needs to follow up on making and providing transportation in the delivery of the fruit so that it can last a long time. Transportation and facilities provided in the form of refrigerated containers (reefer) for shipping fruits to maintain product value and minimize the wasting in the cool chain system. The apple palette was the object of this study with detailed structural variables from the T-bar reefers floor and airflow resistance of the wooden pallets. Energy consumption from reefers with different apple package designs will be identified to see the impact of the ventilation area on the use and energy savings of both low and high fruit packaging densities. In addition, the effect of the evaporator fan on energy consumption was simulated with apples operating at low, medium, and high speeds as well as the variable speed of the evaporator fan. Thus, the Computational Fluid Dynamics (CFD) method was developed to be able to estimate airflow, heat transfer, and energy use with satisfactory accuracy. After that, a validated model is used to investigate the performance of ventilated packaging boxes that are commonly used. [ABSTRACT FROM AUTHOR]

Air conditioner has been one of the main necessities for mankind, especially for people living in warm climate countries such as Indonesia. The need for air conditioner itself functions for the comfort of users and also operating functions of certain equipment. Due to global warming, increase in the temperature of the Earth forces greater energy consumption of air conditioner to reach the required room temperature requested by the user. This increase in energy consumption has been the focus of the Indonesian government in finding solutions to help reduce energy consumption from non-renewable energy power plants while still fulfilling societies demand. One solution is applying energy labelling for air conditioners using Energy Efficiency Ratio (EER) as a parameter. In order to calculate the EER of air conditioners, a controlled room environment is needed, thus the reason of creating the Psychrometric Chamber. One of the required data to calculate EER is air flow from evaporator. Airflow measurement can be calculated from pressure different between inlet and outlet of divergent nozzle. Pressure transmitter is the instrument that can measure the pressure different. The result of this research is finished construction of an air flow measurement device which consist of nozzle box, perforated plate, nozzle plate, divergent nozzle, pressure transmitter, flexible duct, and blower. [ABSTRACT FROM AUTHOR]

Treatment of waste through landfill technique has considered ineffective and caused many damages to both the environment and economic problems. Therefore, the Indonesia government plans to build an Intermediate Treatment Facility equipped with incinerator as the waste machine. The functionalism movement that developed since the beginning of the 20th-century cause services such as incinerator to be designed without understanding and respecting its surrounding environment and its users' comfort. This research evaluates by designing the recycling of incinerator in the architectural context. The design method uses the principle of passive breathing with the chimney effect which has a smart and straightforward principle of creating a temperature difference between the inlet in the area under the building and the outlet on the roof so that cold air can enter the building, and the hot air inside the building moves up and out of the building. The final design concludes the recommended architectural strategies such as adjusting the orientation of the building towards the arrival of the airflow to increase the area exposed to the wind, keeping the ambient temperature of the building low, especially in areas that have inlets, designing passive strategies in areas exposed to solar radiation according to the needs of inlets and outlets, and organizing the space arrangement in a building to generate the stack effect. [ABSTRACT FROM AUTHOR]

There is a lot of energy potential in biomass wastes in Indonesia, and one of those is rice husk. This research will create a suitable model for drying and pyrolysis zones in rice husk gasification. The single particle model is chosen as the model since it can help to observe conversion happened within a particle in detail. This is important because with that, we can understand the compositions of pyrolysis gas, char, and primary tar in drying and pyrolysis zones in rice husk gasification. To validate the model, air flow rate is chosen as the variable that would be varied. The objectives of this research are to check whether the model is suitable for modelling drying and pyrolysis zones in rice husk gasification as well as to understand the effects of air flow rate in the product compositions using the simulation. The results show that the primary tar content is increasing by the increase of air flow rate, while the pyrolysis gas content is decreasing, and the char content is constant. The results show that the numerical model is considerably suitable for modelling drying and pyrolysis zones in rice husk gasification. [ABSTRACT FROM AUTHOR]

The investigation on combustion characteristic and kinetic parameters of Tetraselmis chuii microalgae was carried out under thermogravimetric analyzer. The sample of microalgae has prepared by the Center for Brackish Water Aquaculture (BBPBAP) Jepara, Indonesia. The drying out the water content in the sediment was performed by an oven at temperature 80 °C as long as 24 h. The dry sample then the crushed and followed by sieving to be mesh size of 60. The thermal decomposition of Tetraselmis chuii microalgae was investigated by a thermogravimetric apparatus, in which the 10 mg of sample was heated up in the temperatures range of 25-900 °C with an atmospheric airflow rate of 50 mL/min and a heating rate of 15 °C/min. The mass loss during temperature expansion was recorded by a computer to be a thermogravimetric (TG) graph and used to evaluate the thermal characteristic of the sample. The kinetic parameters were evaluated in the active combustion zone by the Arrhenius method, resulted in the respective values of reaction order (n), logarithmic frequency factor (log A), and activation energy (E) were 1.24, 9.0 min−1 and 101.05 kJ mol−1 for stage II, and 2.38, 33.31 min−1 and 502.88 kJ mol−1 for stage IV. [ABSTRACT FROM AUTHOR]

Indonesia has abundant natural resources spread throughout the islands. The utilization of these natural potentials has not been fully played and developed to meet daily needs such as for cooking. The purpose of this study is to explore the potential of leaf litter as a domestic source of energy for cooking. In particular, a set of laboratory scaled experiment was conducted by using leaf litter of the species Artocarpus champaden, L., Nephelium lappaceum, L., and Mangifera indica, L. In Indonesia these species are known as Cempedak, Rambutan, and Mangga trees which produce fallen leaf throughout the years. A way of reducing the leaf litter problems by local people is by collecting it from the garden and roof, then burn it to reduce the volume. The experimental work was carried out through some steps. The leaf litter was transformed to biomass briquettes fuel in order to increase energy content for combustion by adding Canola Oil and Starch as a binder. The briquettes were produced manually with minimum mechanical works. Thermal analysis, including calorific value, proximate and ultimate analysis, was performed by standard method and equipment. The experiment was carried out by using a biomass stove with a fuel chamber volume of approximately 660 cm3. A fan was attached to the stove to supply an updraft forced vortex flow of air. Water Boiling Test method was performed to measure the burning characteristic and stove efficiency. It was found that the briquettes (100 grams) from all leaf type tested can boil the water of 1000 ml within 7 minutes. In general, the burning performance of the briquettes were related to proximate and ultimate analysis of the samples. Nevertheless, by comparing the performance using Water Boiling Test suggested that the discrepancies of the performance using different types of leaf litter were not significant. This work showed that leaf litter has the potential as a reliable energy source for cooking in household at rural areas. [ABSTRACT FROM AUTHOR]

Cassiterite from Bangka, Indonesia, has mineralogical characteristics different from cassiterite in other countries. The purpose of this work is to investigate the effect of acid concentrations and leaching times in the aerated reactor on the dissolution of cassiterite. Ten grams of cassiterite with ~100-mesh particle size was dissolved in variation concentrations of HCl (5, 10, 15, 20 and 37 %.) at different leaching times (30, 60, 120, 180, 240, 300 and 360 min). The processes were carried out using an aerated reactor with air flow of 540 liter/hours in an oil bath. The processing result showed that the highest dissolution of cassiterite was about 8.3 % at 37 % HCl concentration. The stable dissolved cassiterite was approximately 3.9-4.7 % from leaching processes using solvents of 10-20 % HCl concentration. It seems that the associated minerals of cassiterite were difficult to be separated from the main mineral of tin using hydrochloric acid solutions in the aerated reactor. The highest percentage of extraction of Fe, Si, Ti and Sn by HCl solution for 120 min in the aerated reactor was approximately 30.6 % Fe, 1.6 % Si, 1.3 % Ti, and 0.1 % Sn, respectively. [ABSTRACT FROM AUTHOR]

The prospect of microalgae Spirulina platensis-synthetic waste mixture (SPSW) as alternative energy to replace fossil fuels was investigated in terms of the elemental composition changes during the combustion process. The microalgae Spirulina platensis (SP) sample was achieved from BBPBAP Jepara, Central of Java, Indonesia. While synthetic waste (SW) sample was taken from a temporary shelter in Malang City. A quantity of 30% of SP and 70% SW were mechanically mixed to warranty the uniform mixture in sample’s powder. SPSW sample was tested its chemical content by using Energy-dispersive X-ray (EDX). To understand the stage of thermal decomposition, the samples firstly were tested under the thermogravimetric (TG) instrument. The combustion has been performed at a heating rate of 10 °C/min at the temperature range of 25–1000 °C, under 100 ml/min constant flow rate of air atmosphere. From this experiment’s result could be specified the temperature of onset and end of the decomposition stage. In accordance with these temperature parameters, the new samples were heated up in the furnace with the similar TG’s condition. The residuals leftover at every stage then were analyzed their elemental composition to evaluate the changes of their content. The TG result showed that SPSW combustion occurred in five stages. Started with initial devolatilization at the temperature range of 25–302 °C, the main thermal decomposition which separated into two zones (302–435 °C and 435– 505 °C), transition stage stretched out between 505–613 °C, the combustion of char at range of 613–710 °C, and the last stage was the slow-burning reaction of residual char at 710–1000 °C. The EDX analysis result showed that organic contents of C and O and inorganic elements of Cl and Ca were encountered as the most elements in the parent and residual materials in the sample at each decomposition stage during combustion. The raw material sample of SPSW contained C and O that were 10.97 and 5.86 mg, respectively. At the temperature of 302 °C, the amount of C and O elements were decreased. At the range of 435–505 °C occurred the major mass loss, indicated the plenty of organic content of C and O were released in a short time. The residue of SPSW at the temperature of 710 °C, designated by the elemental composition including C, O, Cl, and Ca that was 0.50, 0.80, 0.40, and 0.60 mg, in that order. [ABSTRACT FROM AUTHOR]