Studi Inhibisi Formasi Kristal Es Dengan Krioprotektan Sukrosa Dan Glicerol

A large number of investigations have been carried out to understand the mechanism of freezing and mechanical damages in biological materials. Harmfull ice crystal has been proposed to be a factor causing injury to biological materials during the freezing. How to control,eliminate, or prevent the intracellular ice formation become an important research topic in fundamental cryobiology. Microscopic observation of the freezing process of onion epidermistissue have been made using a solidification stage in order to study the possibility ice crystal formation inhibition using glycerol and sucrose as a cryoprotectant. Experiments conductedunder cooling rates of 40oC/min and 70oC/min. The results indicated that the increasing glycerol can depress the freezing initiation temperature. However, vitrification of onion cells only can beachieved when we used high concentration of cryoprotectant (more than 70%vol sucrose(0.8M)+30%vol glycerol) with relatively rapid freezing (more than 70oC/min)

Parameter Kinetik Char Hasil Pirolisis Serbuk Kayu Mahoni (Switenia Macrophylla) Dengan Variasi Heating Rate Dan 1 Temperatur

The value of k (rate constant) is one of the important parameters in the equation speed of reaction (kinetics of reactions). This paper discusses the value of k (rate constan) at each heating rate (673 K / h and 873 K / h). Where k is the value obtained by calculating the value of k temperature 523 K, 623 K, 723 K, 773 K and 873 K heating rate of 673 K / h and k values of temperature 523 K, 623 K, 723 K, 773 K and 873 K heating rate 1073 K / h. From the k value of each temperature, calculated values of k in the heating rate. Calculation results obtained kinetic parameters heating rate of 673 K / h Kinetic is = 24,022 . −1230 ⁄ , Ea = 10226.2 kJ Mol -1 , A = 269.4548 min -1 and a heating rate of 1073 K / h is = 8,998 . , Ea = 6550.6 kJ Mol -1 , A = 100.9273 min . From the k value of each heating rate validated into the mass loss is calculated, which obtain the actual mass loss results with the mass loss calculation results of kinetic equations for each temperature and heating rate can be seen that the value of mass loss value calculation results is approaching mass reduction so the actual kinetic equation respectively temperature and heating rate. Rate constan) is one of the important parameters in the equation speed of reaction (kinetics of reactions) -

Performansi Purifikasi Biogas Dengan KOH Based Absorbent

The absorpstion of CO2 is aimed to increase the methane gas fraction in biogas. Enhancing methane fraction hopefully will increase the total energy of the biogas it self. The purification process of biogas minimizing another elements maintains combustion, especially minimizing H2O, CO2, and H2S. The purification using KOH as the absorbent to decrease the CO2. The result shown that the content of CO2 decreased into 27% from 35.5%, the average content of CH4 increased from 18% to 48.5%. Increasing KOH composition decreases bubble generator diameter and mass flow

Karakteristik Produksi Browns Gas Dengan Menggunakan Tenaga Matahari

Renewable energy has potentials to be developed to meet our energy needs in the future. One promising energy source is browns gas. Browns gas is a mixture of di-atomic and mono-atomic of hydrogen and oxygen. One effort to produce browns gas is through the process of electrolysis of water. However, the process of electrolysis still considered a process uneconomical and inefficient, since the energy of electrochemical decomposition of water is relatively high. Thus, the challenge of brown gas production is reducing electrical energy. In this study, we propose to use solar energy for browns gas production plant, since the solar energy is environmentally friendly energy sources available so abundant in Indonesia. The experiment was carried out in two methods. First, the electrolysis was done using electricity produced by the solar panel directly without voltage control. The second method, the voltage of electricity from the solar panel was controlled using a regulator then it used for the water electrolysis. The results show that the direct method generates fluctuative electricity with the rate power of 29.67 Watt. This electricity was used for electrolysis process and produced brown gas 0,1393 g for 4 hours. On the other hand the in-direct method generated power relatively constant at 18.3 Watt and produced the brown gas about 0.1365 g

Purifikasi Biogas Dengan Variasi Ukuran Dan Massa Zeolit Terhadap Kandungan CH4 Dan CO2

Nowadays, the development of the renewable energy very rapidly. It is driven by the nature of the renewable energy that has been proven to be cleaner than conventional energy, so an increase in the use of renewable energy continues to rise. Biogas is produced from biological processes (anaerobic digester) is capable of producing gas such as CH 4 , CO 2 , H 2 S, and other gases. Therefore it is very important to make the process of refining the biogas. In this research, using the biogas purification process purification method stratified, with a solution of sodium hydroxide with zeolite is purified again and again purified with activated charcoal, hence the storied purification. In this study focused on the observation of zeolite as an adsorbent, the size of the fine and coarse zeolite, and zeolite are varied mass of 50 grams, 100 grams and 150 grams. In 60 minutes, the best result obtained on zeolites fine size with a mass of 150 grams of CO 2 obtained down to 4.07%, but the pressure dropped to 0.65 kPa. With the size of the coarse zeolite at 4.26% CO 2 , with a pressure drop of 0.84 kPa. After the purification process, zeolite proved to be hidrofill with the content of the zeolite fine biggest water with 5.4%

Pengaruh Diameter Inner-Helical Fin Terhadap Characteristic of Performance Counter Flow Heat Exchanger

The study of energy conservation using the head exchanger with different fin shapes havebeen carried out, including research on the counter flow heat exchanger using a helical spiral shaped fin is placed on the inner pipe. The problem lies in the acquisition of the influence of the diameter of the helical fin to the characteristic of performance counter flow heat exchanger. The diameter of the helical fin which the test is 8 mm, 12 mm and 16 mm. The objective is achieved, the effect of the diameter of the helical fin characteristic of performance counter flow heat exchanger in the increase of hot water discharge 400 liters / hour, 500 liters / hour, 600 liters /hour, 700 liters / hour, 800 liters / hr and 900 liters / hour. Method of design of experiments with laboratory-scale experiments using a set-up equipment double tube heat exchanger is the method used. The results obtained, the highest effectiveness for all types of helical fins foundon discharge 400 liters / h with the order from highest to lower the effectiveness of internal diameter of 12 mm reached 17.66%, diameter of 8 mm effectiveness reaches 15:56% and the internal diameter of 16 mm effectiveness of achieving 14.29%. For the plain tube efektiftasobtained 11:48%

Pengaruh Temperatur Terhadap Entalpi Dan Kinetic Rate Gas Pirolisis Kayu Mahoni

This study was conducted to determine the effect of temperature on gas enthalpy and kinetic rate of mahogany wood powder pyrolysis results. Research process carried out experimentally with the temperature 673 K, 773 K, 873K, 973 K and 1073 K. Pyrolysis process is carried out for 2 hours with a particle size of sawdust from 0.5 to 1 mm. The results showed that the enthalpy value increase as the temperature increase. Highest enthalpy value achieved at 1073 K, with enthalpy value is 35015.97J.Kinetic rate for temperature 873 K, 973 K and 1073 K is = 1,484 −2759/ , kinetic rate for temperature 673 K and 773 K is = 16,5306 −5368/ and = 3,0373 −2980/ respectively. As the temperature increase, activation energy (Ea) to decompose biomass into gases is decrease