Arrhenius Method Research Articles

Thermo‐oxidative aging of acrylonitrile‐butadiene rubber gaskets with real geometry used in plate heat exchangers

AbstractThis study investigates the effects of aging on the physical and mechanical properties of commercially available acrylonitrile‐butadiene rubber (NBR) gaskets while maintaining their original geometry. Thermo‐oxidative cycles with 10 and 70 mm in length specimens were conducted from 80 to 170°C up to 180 days. The samples were analyzed employing compression set (CS), hardness, indentation modulus, cross‐link density, total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR), and thermogravimetry. The results showed that longer specimens presented better resistance to thermo‐oxidative aging. Indentation results indicated regular oxygen permeability into the entire samples up to 110°C, while at higher temperatures, limited diffusion oxidation (DLO) effects promoted non‐uniform aging. Time–temperature superposition (TTS) and Arrhenius methods were applied to predict the specimens' lifetime using CS as a failure criterion. Activation energies for 10 and 70 mm samples were 68.74 and 43.63 kJ mol−1, respectively. Thus, the 70 mm specimen's lifetime was greater than 10 mm. For temperatures below ≈38°C, the response to the thermo‐oxidative aging is independent of specimen length. Therefore, in determining the lifetime of gaskets with complex geometry, longer specimens are recommended to provide more reliable results than those suggested by the standards.

Biochemical and Thermodynamic Characterization of β amylase from Dioscorea alata L.

β-amylase (E.C.3.2.1.2) is a starch hydrolyzing enzyme fondly used in foods, pharmaceuticals, and brewing industries to convert starch into maltose. The aim of this study was to determine the physicochemical, kinetic, and thermodynamic properties, as well as the potential industrial use of β-amylase from Dioscorea alata L. Studying the enzyme stability with Arrhenius methods, showed that the enzyme was stable at a temperature range of 20–500C, and had good pH stability by retaining over 50 % of its initial activity over a wide range of pH from 4 – 8 and kinetic stability by increasing the half-life of the enzyme. The activation energy (Ea) for catalysis by water yam β-amylase at 250C was 6.45kcal/mol. The activation energy (Ea), half-life, free energy change (ΔG‡), enthalpy change (ΔH‡), and entropy change (ΔS‡) for inactivation at optimum temperature (400C) and pH 5 were 13.92 kcal/mol, 41.25 min, 20.89 kcal/mol, 13.30 kcal/mol and -24.25 cal/mol/K respectively. Km and Vmax values were reduced from 2.25 to 2.13mg/ml and 2.95 to 1.48 µmol/min/ml respectively. The optimum pH shifted from 5 to 6, while the Optimum temperature increased from 40 to 500C after immobilization. Enzyme retained up to 67 % activity after 5 cycles. The enzyme would be of importance in manufacturing companies based on the kinetics and application features reported in this study since it is a cheap and readily available source.

Pendugaan Umur Simpan Ikan Patin Salai Menggunakan Metode Akselerasi Dengan Kemasan HDPE dan Teknik Pengemasan Aluminium Foil

The goal of this research was to estimate the shelf life of salai catfish using the ASLT (Accelerated Shelf-Life Testing) method with high-density polyethylene (HDPE) plastic, vacuum aluminum foil, and non-vacuum aluminum foil. By storing the salai catfish for thirty days at different temperature levels, namely 30, 35, and 40°C, the acceleration method was used to predict the shelf life. Changes in rancidity sensory and thiobarbituric acid (TBA) levels were observed. The obtained data were analyzed using linear regression to show the relationship between storage time and the measured variables. Furthermore, the Arrhenius method was used to calculate the shelf life of salai catfish in order to compare the quality degradation of salai catfish. The best result was obtained in the treatment of salai catfish with vacuum aluminum foil was 32,56 days at 30°C based on the TBA test. The regression equation were y= -2875,7x + 5,2812, R2= 0,9855.

Isothermal decomposition of CL- 20 before and after thermally induced ε-γ crystal transformation

The ε-γ crystal transformation of CL-20 (hexanitrohexaazaisowurtzitane) was examined using a self-made constant temperature decomposition gas measuring device, and the isothermal decomposition kinetic parameters of ε-and γ-CL-20 with different crystal phases were obtained. Results show that the pressure temporal curves of CL-20 before and after crystal transformation have their own decomposition mechanism, indicating that the phase transformation has a significant effect on CL-20 decomposition. The kinetic parameters of ε- and γ-CL-20 were also calculated by Arrhenius and Mode matching methods. The activation energy (Ea) of ε-CL-20 decomposition was 118.82 kJ·mol−1 in the temperature range of 423–443 K, and the Ea of γ-CL-20 decomposition was 77.74 kJ·mol−1 in the temperature range of 453–468 K. The storage life of ε- and γ-CL-20 was estimated by Semenov equation. When the reactivity reaches 0.5 %, the storage time of ε-CL-20 at room temperature (298 K) is 227.8 years. Finally, the gas and solid residues obtained after CL-20 decomposition by SEM, FT-IR, and GC techniques. The possible decomposition mechanism of ε-CL-20 was proposed.

PENDUGAAN UMUR SIMPAN PRODUK MINUMAN GINGER LATTE MENGGUNAKAN MODEL ARRHENIUS

Information about a product's shelf life is essential for the food industry to ensure the safety and quality of the product. Process development is needed if the product's shelf life is short-lived. This study aimed to increase the shelf life of ginger latte with sterilization at 121oC temperature using an autoclave for 10, 15, and 20 minutes then being hot filled at 90oC. Product sterilized in aluminum foil pouch then transferred to PET plastic bottles with hot fill method. Beforehand, the product characteristics were tested on the organoleptic test, pH, and total dissolved solids before being treated with sterilization and hot fill. The Arrhenius method was used to calculate product shelf life with sensory, pH, and total dissolved solids as parameters. The product shelf life before sterilization and hot filling were 18 days in storage at 10oC. Based on the calculation using the ASLT method Arrhenius model, the product shelf life was 35 days with sterilization at 121oC in 25oC storage temperature. The pH and total dissolved solids on day 28 after sterilization were recorded at 5.33 and 14.5oBrix for 15 minutes, respectively, and 5.83 and 14.9oBrix for 10 minutes of sterilization, respectively.Keywords: accelerated shelf life study (ASLT), ginger latte, sterilization, shelf life

Investigation of Pyrolysis Behavior of Sewage Sludge by Thermogravimetric Analysis Coupled with Fourier Transform Infrared Spectrometry Using Different Heating Rates

In this study, pyrolysis of municipal sewage sludge samples from different sources including cattle and chicken manure as well as brook mud, was investigated using a thermogravimetric analysis coupled with a Fourier transform infrared spectrometer (TG-FTIR) at different heating rates (25, 50 and 100 °C/min). In order to determine the kinetic parameters, Arrhenius, model-free Kissinger–Akira–Sunose (KAS), as well as Friedman and Flynn–Wall–Ozawa (FWO) methods were compared. The thermogravimetric results revealed that pyrolysis involved different stages, and that the main decomposition reactions took place in the range of 200–600 °C. In this range, decomposition of biodegradable components (e.g., lipids and polysaccharides), proteins and carbohydrates occurred; meanwhile, there were samples (e.g., cattle manure, brook mud) in which the decomposition step could be observed even at temperatures above 700 °C. According to the Arrhenius method, the activation energies of the first decomposition stage were between 25.6 and 85.4 kJ/mol, while the activation energies of the second and third stages were in the ranges of 11.4–36.3 kJ/mol and 20.2–135 kJ/mol, respectively. The activation energies were also calculated by the KAS, Friedman and FWO methods, which were in the range of 100–300 kJ/mol for municipal sewage sludge or distillery sludge, and ranged between 9.6 and 240 kJ/mol for cattle manure, chicken manure and brook mud samples.

Estimating the Shelf Life of Oyster Mushroom Rendang packed with Vacuum or Non-Vacuum technique by the Application of the Arrhenius Methods

Rendang is a famous traditional food from West Sumatra, Indonesia. Oyster mushroom rendang is made from oyster mushrooms. Based on its composition, the degradation of fat is its critical point during storage. Proper packaging can extend the shelf life of oyster mushroom rendang. The purpose of this study was to determine the shelf life of oyster mushroom rendang that pack in vacuum and no vacuum packaging using the Accelerated Shelf-Life Testing (ASLT) method according to the Arrhenius equation. As a result, at a temperature of 25°C, oyster mushroom rendang packaged in vacuum packaging has a shelf life of 613 days and in non-vacuum packaging has a shelf life of 43 days.

Shelf life evaluation of formulated cookies from Hanjeli (Coix lacryma-jobi L.) and Moringa leaf flour (Moringa oleifera)

Hanjeli (Coix lacryma-jobi L.) and moringa leaf (Moringa oleifera) remain underutilised despite their high nutritional value for food. In the present research, cookies made from hanjeli (Coix lacryma-jobi L.) with moringa leaf flour (Moringa oleifera) have been developed. Hanjeli cookies were measured for nutritional composition and shelf life assessment. The shelf life evaluation of hanjeli-moringa cookies was calculated using two approaches, which were accelerated shelf life testing (ASLT) methods with critical moisture content and the Arrhenius method. The results of the nutritional composition analysis showed that hanjeli-moringa cookies contain protein (9.14%), fat (24.67%), carbohydrates (61.62%), crude fibre (4.85%), and energy (505.01 Kcal). Using the Arrhenius method, the shelf life of hanjeli-moringa cookies was 95.46 days at room temperature and 97.63 days at 20 °C. Meanwhile, the shelf life of cookies using the critical moisture content approach was 170.57 days. Shelf life is influenced by initial moisture content, critical water content of the product, packaging surface area and permeability, saturated vapour pressure, and slope sorption isotherm curve. The formulated cookies have significant amounts of nutrients that are acceptable and safe for consumption, with guaranteed desirable sensory properties. The result of this study shows that hanjeli-moringa cookies can be used as an alternative food for people who need high energy in a practical way of serving or ready to eat.

Shelf-Life Prediction of Shallot Powder Using Accelerated Shelf-Life Testing (ASLT) Method by the Arrhenius Equation Approach

The storage process of shallot powder can cause a quality decrease. This study aims to estimate shelf-life of shallot powder at various storage temperatures and determine quality changes during storage. This study used a Completely Randomized Design with two factors to determine quality changes of shallot powder, i.e. the coating and storage temperature. The statistical analysis results showed that the coating, storage temperature, and interaction between the two factors affected Volatile Reducing Substances (VRS) levels. The two factors and their interaction do not influence the water content. Shelf-life estimation was performed using the Arrhenius method. Coated shallot powder has a longer shelf-life than uncoated shallot powder. Shelf-life determination was performed based on water content parameters. The shelf-life of uncoated shallot powder was 337 days at 30 °C, 322 days at 40 °C, and 309 days at 50 °C. The shelf-life of coated shallot powder was 353 days at 30 °C, 340 days at 40 °C, and 328 days at 50 °C. The coating process can extend the shelf-life of shallot powder.

Pendugaan Umur Simpan Garam Mandi (Bath Salt) Aroma Serreh Menggunakan Metode Accelerated Shelf Life Testing (ASLT)

Salt contains compounds of magnesium chloride, magnesium sulfate, magnesium bromide, and other trace compounds. In general, salt is divided into consumption salt and industrial salt. Bath salt is a salt product that dissolves in water and reduces wrinkles on the hands. The constituent components of bath salts are Epsom salt, sodium bicarbonate, SLES, cornstarch, olive oil, citronella oil, and alcohol, the packaging used is glass packaging. Shelf life is done by accelerating the degradation reaction using high temperature storage and simulating the data obtained. The purpose of this study was to determine the quality characteristics of bath salts before and after storage and to determine the shelf life of bath salts with the aroma of lemongrass. This research was conducted at the Quality Analysis Lab of the Agricultural Industrial Technology Study Program, Faculty of Agriculture, Trunojoyo University, Madura from September to October 2021. Shelf life was estimated using the Arrhenius method. Based on research at a temperature of 28, the shelf life of bath salts is 180.86 or 6 months 1 day, while at a temperature of 35 is 85.85 or 2 months 26 days. It is proven by the value of the shelf life which is getting shorter with the higher the storage temperature. An increase in temperature causes a greater rate of reaction

Enhancing hydrogen storage performance via optimizing Y and Ni element in magnesium alloy

Magnesium-based hydrogen storage materials are considered as one of the most promising candidates for solid state hydrogen storage due to their advantages of high hydrogen capacity, excellent reversibility and low cost. In this paper, Mg91.4Ni7Y1.6 and Mg92.8Ni2.4Y4.8 alloys were prepared by melting and ball milling. Their microstructures and phases were characterized by X-ray diffraction, scanning electron microscope and transmission electron microscope, and hydrogen absorbing and desorbing properties were tested by the high pressure gas adsorption apparatus and differential scanning calorimetry (DSC). In order to estimate the activation energy and growth mechanism of alloy hydride, the JMAK, Arrhenius and Kissinger methods were applied for calculation. The hydrogen absorption content of Mg92.8Ni2.4Y4.8 alloy reaches 3.84 wt.% within 5 min under 350 ℃, 3 MPa, and the maximum hydrogen capacity of the alloy is 4.89 wt.% in same condition. However, the hydrogen absorption of Mg91.4Ni7Y1.6 alloy reaches 5.78 wt.% within 5 min, and the maximum hydrogen absorption of the alloy is 6.44 wt.% at 350 ℃ and 3 MPa. The hydrogenation activation energy of Mg91.4Ni7Y1.6 alloy is 25.4 kJ/mol H2, and the enthalpy and entropy of hydrogen absorption are -60.6 kJ/mol H2 and 105.5 J/K/mol H2, separately. The alloy begins to dehydrogenate at 210 ℃, with the dehydrogenation activation energy of 87.7 kJ/mol H2. By altering the addition amount of Ni and Y elements, the 14H-LPSO phase with smaller size and ternary eutectic areas with high volume fraction are obtained, which provides more phase boundaries and catalysts with better dispersion, and there are a lot of fine particles in the alloy, these structures are beneficial to enhance the hydrogen storage performance of the alloys.

Accelerated shelf life test method with arrhenius approach for shelf life estimation of tongkol ‘euthynnus affinis’ balado in cans

Many people in Indonesia consumed tongkol fish by processing it into balado tongkol. The process carried out to extend the shelf life of the product is by packing it in cans. Information related to shelf life was needed for canned food, so that it can guarantee that the food was still good for consumption. This study aims to determine the shelf life of balado tongkol in cans from TEFA Fish Canning with the Arrhenius method. Arrhenius is the method of estimating shelf life used was ASLT (Accelerated Shelf Life Test). The ASLT method requires a relatively short testing time with an acceptable level of accuracy. This research was conducted at the TEFA Fish Canning and Food Processing Laboratory of Politeknik Negeri Jember in March – July 2021. Estimating the shelf life used the reaction approach that increases the TBA number as a critical parameter. The kinetic reaction of increasing the TBA number in canned balado tongkol followed the ordo 0 reaction. The results showed that the shelf life of balado tongkol in cans at room temperature was 24,6 weeks.

An effective method to remove organic sulfur in coal: Effects on the physicochemical properties and combustion kinetics

The present work investigated an effective method to remove organic sulfur in coal utilizing different microorganisms (Nocardia mangyaensis and Pseudomonas putida). The most obvious finding to emerge from the sulfur forms analysis is that the organic sulfur removal of these two bacterial strains on Yunnan bumuga high-sulfur coal were 61.58% and 54.19%, respectively. This result may be confirmed by the Fourier transform infrared spectroscopy (FTIR) analyses that there were obvious decreases of intensity after biotreatment in the CS bond. Besides, the results of X-ray diffraction and X-ray photoelectron spectroscopy showed that major mineralogical phases in the forms of kaolinite and pyrite exist in raw coal. And more than 80% of thiophene and sulfoxide in the raw coal were removed by N. mangyaensis and P. putida. In addition, the results of the thermogravimetric analysis indicated that the combustion performance of biotreated coal samples was better than that of raw coal, and the most probable models to describe the combustion kinetics for biotreated coal and raw coal at different stages were obtained by the Arrhenius method and Coats–Redfern method.

Effect of cooking oil on the characteristics and shelf life of shredded catfish (Clarias sp)

The purpose of this research is to identify the characteristics of shredded catfish (Clarias sp) processed with and without cooking oil and determine the shelf life by using the Arrhenius method. The shredded catfish was made by filleting the fish and soaking in a 2% vinegar solution for 10 minutes, and boiling the fillets for 15 minutes in a 2% salt solution mixed with 2% bay leaves and 2% lemongrass with the ratio of fillet: solution (1:2 (w/v)). The cooked fillets were then pressed, shredded into small pieces, and added with spices (2% red onion, 3% garlic, 15% granulated sugar, 1% coriander, 1% galangal, and 0.5% flavoring powder) and 20% coconut milk, then cooked until it dried. The shredded catfish was observed for its proximate values, while the shelf life was determined using the acceleration method (Arrhenius) at three different storage temperatures and day of observation, i.e. at 25°C was for 0, 10, 20, 30, 40 days; at 35°C was for 0, 7, 14, 21, 28 days and at 45°C was for 0, 3, 6, 9, 12 days. The parameters of observation for shredded catfish’s shelf life were peroxide value, Aw, total plate count (TPC), and sensory test (hedonic). The result of proximate value showed that the protein content of shredded catfish with oil was lower than without oil, while moisture content was higher for treatment using oil. The shelf life of shredded catfish with cooking oil was shorter than without cooking oil, estimated for 83 days at 25°C, 55 days at 35°C, 47 days at 45°C, compared to 155 days at 25°C, 103 days at 35°C, and 62 days at 45°C, respectively. This was supported by the panelist’s preferences for shredded catfish without oil at the end of the observation. These results indicate that the use of cooking oil during the cooking process of shredded catfish greatly affects the product’s shelf life.

Pendugaan Umur Simpan Bubuk Kopi Arabika Menggunakan Metode Arrhenius dengan Kemasan Aluminium Foil dan Plastik (Polipropilen)

The storage method is one way to maintain coffee quality. Storage with aluminum foil and plastic (PP) packaging is an effective and safe technology to protect coffee grounds. Specialty coffee powder cannot be accepted if the organoleptic score is below 80, for that it is necessary to estimate the shelf life. This study aims to analyze the quality degradation of Bondowoso arabica coffee powder based on specialty standards using the SCAA protocol during storage with aluminum foil packaging and compare it with plastic packaging (PP) and estimated the shelf life of Bondowoso arabica ground coffee products based on flavor value parameters using the arrhenius method. Coffee powder quality degradation with plastic packaging (PP) is faster than aluminum foil packaging. This is because plastic packaging on the fourth day with a temperature of 40°C is not meet specialty standards. The greater the temperature used, the greater the decrease in quality. The shelf life of coffee powder uses aluminum foil packaging, which is 3 days at 40°C, 2 days at 50°C, and 1.3 days at 60°C. Whereas with plastic packaging (PP), the shelf life is shorter, which is 2 days at 40°C, 1.2 days at 50°C and 1 day at 60°C. Keyword: accelerated Shelf-Life Testing (ASLT), aluminum foil, arabica coffee, packaging, shelf

Estimation of Shelf Life of Rinuak Fish Nugget (Psilopsis, Sp) With the addition of Sago Flour And Pumpkin Using The Arrhenius Method

This study aims to obtain the formula for making rinuak nuggets that are most preferred by the panelists. The formula was prepared by varying the rinuak fish, sago flour and pumpkin. The most preferred formula by the panelists was then tested for shelf life using the Arrhenius method . The results showed that the formula nugget most preferred is the treatment of C ( rinuak fish : flour Sago: pumpkin = 70%: 15%: 15%). The results of further research until the 30th day of storage at a temperature of -15°C still have good quality , in This is assessed from the number of microbes and the percentage of water content that is still in accordance with the established standards. Keywords-- Rinuak Fish, Nugget , Sago Flour, Pumpkin, Shelf Life, Arrhenius

Altered rheokinetic and mechanical behavior of anhydride cured epoxy resin due to addition of cellulose nano-crystals

In this work, the effect of cellulose nanocrystals (CNC) addition on the rheo-kinetic behavior and mechanical strength of the anhydride cured epoxy system is studied. The study is conducted under non-isothermal conditions at five different heating ramp rates, namely 1, 2, 5, 8, and 10℃/min. The effect of CNC concentration on the activation energy is also analyzed. The maximum activation energy is observed for 0.5% CNC modified resin with a value of 112.4 kJ/mol for 0.8 degree of conversion. Furthermore, the non-isothermal Arrhenius method is used to predict the rheo-kinetic model that correlates the degree of cure and complex viscosity of the CNC modified resin system. The predicted viscosity model agrees with the experimental data to a great extent with Absolute Average Relative Deviation values in the range of 0.78-0.998. Additionally, the flexural strength of nano-composites is evaluated and found to be increased from 23.6 MPa to 38.2 MPa for neat resin and 2% CNC modified resin sample, respectively. The developed rheo-kinetic modeling will be helpful for efficient and high strength nano-composite product formulation.

Accelerated aging studies of the selected commercial films

The Arrhenius method was used to investigate the effect of accelerated aging conditions on the physical and mechanical properties of polymer films for technical, medical, food and office applications. Temperature and UV radiation were taken into account as environmental factors. It was shown that the tested films are more sensitive to thermal degradation than UV radiation. The reduction in tensile strength after thermal aging does not exceed 40%, and in the case of UV radiation, 14%. The estimated lifetime of the tested films is over 5 years.

Model Arrhennius Untuk Memprediksi Penyimpanan Kelapa Parut Kering

Dry grated coconut is a processed coconut product that can be directly used by consumers without requiring further processing. In order for dried coconut products to last longer, a good storage process is needed. Storage is intended to maintain the value of the stored commodity. One of the models used for estimating shelf life is the Arrhenius model. Parameters in this study were water content, temperature and humidity. Temperature parameters consisted of three treatments,i.e 30°C, 35°C and 40°C. The results showed a decrease in water content data obtained by using the Arrhenius method at each storage temperature for a temperature of 30°C that is 103.9 days, a temperature of 35°C is 74 days and a temperature of 40oC is 60.5 day.

Comparison of flow behaviors of near beta Ti-55511 alloy during hot compression based on SCA and BPANN models

The flow behavior of Ti-55511 alloy was studied by hot compression tests at temperatures of 973−1123 K and strain rates of 0.01−10 s−1. Strain-compensated Arrhenius (SCA) and back-propagation artificial neural network (BPANN) methods were selected to model the constitutive relationship, and the models were further evaluated by statistical analysis and cross-validation. The stress−strain data extended by two models were implanted into finite element to simulate hot compression test. The results indicate that the flow stress is sensitive to deformation temperature and strain rate, and increases with increasing strain rate and decreasing temperature. Both the SCA model fitted by quintic polynomial and the BPANN model with 12 neurons can describe the flow behaviors, but the fitting accuracy of BPANN is higher than that of SCA. Sixteen cross-validation tests also confirm that the BPANN model has high prediction accuracy. Both models are effective and feasible in simulation, but BPANN model is superior in accuracy.