Standard Oven Research Articles

Comparative analysis of non-standardised aging methods for asphalt binder against standard laboratory aging and natural field aging

ABSTRACT This research investigates non-standardised and natural field aging methods, in comparison with standardised ones. Aging in the Rotational Viscometer (RV) for 24 hours was studied. Pressure Aging Vessel (PAV) aging time and film thickness were changed and compared with standard rolling thin film oven (RTFO) and field-aged binders. Finally, a conventional binder preserved from external conditions was tested over 24 months. Results showed that PAV-aged binders may exhibit greater susceptibility to changes captured by RV. The study also noted a higher increase in viscosities at lower shear rates over time in the RV. However, rheological results did not align with RV findings across all binders. Altering asphalt film thickness in the PAV from 32.5 mm to 25 ± 1 mm has a comparable effect to standard RTFO when the original binder is aged directly in the PAV for the same period of time. The recovered asphalt binder from a 15-year-old pavement showed similarities to 25–30 hours for high-temperature measures, and 55 hours for fatigue parameters indicating inconsistency between laboratory and filed aging. Finally, chemical changes indicated by carbonyl index showed that after 24 months of controlled environmental conditions, a conventional binder exhibited only 44% increase in the index compared to RTFO.

Development of a device made on a 3D printer to determine physical properties of grains

The physical properties of grains are essential for harvesting, storage, and commercialization. These properties, such as bulk density and moisture content, are usually measured with self-propelled machines, expensive equipment, or in laboratories, making them inaccessible to small producers. The research developed a low-cost and easy-to-use device that measures these properties. Tested and calibrated with corn and beans using the standard oven method 105°C/24h, it achieved an excellent coefficient of determination (r2) of 0.998 for beans and 0.999 for corn. The bulk density was calibrated using a precision scale and a hectoliter weight kit, resulting in r2 values of 0.928 for beans and 0.926 for corn. The device is a viable option for Precision Agriculture for small producers.

Green Synthesis of carbon quantum dots for enhancing photocatalytic activity: Hydrogen/oxygen evolution and dye photodegradation

Carbon quantum dots (CQDs) have recently attracted attention across various fields due to their small size, high conductivity, fluorescence emission, low toxicity, and other desirable characteristics. In this study, highly fluorescent CQDs with an average diameter of 3.7 nm were prepared via microwave irradiation using a standard commercial microwave oven and glycerol as solvent. Several cation promoters were examined for CQD synthesis, with copper ions ultimately chosen for comprehensive characterization and application. The CQDs were impregnated onto both commercially available and microwave-synthesized TiO2 nanoparticles. The photocatalytic activity was evaluated with respect to the hydrogen and oxygen generation. Under the employed conditions, the oxygen evolution reaction (OER) exhibited over 12 times higher efficiency than the hydrogen evolution reaction (HER). The enhanced OER activity is attributed to the high electronic conductivity of the small Cu doped CQDs@TiO2 (Cu-CQDs@TiO2) facilitating an efficient electron transfer for the OER . Visible light activity (λ ≥ 400 nm) was demonstrated by photodegradation of the indigo carmine (IC) solution used as a model pollutant. Irradiation in the presence of the Cu-CQDs@TiO2 photocatalyst resulted in complete degradation of the dye in less than 3 hours. The results presented here provide a promising methodology for designing high-performance photocatalysts based on environmentally friendly CQD syntheses. Crucial applications, from renewable energy production to environmental remediation, will benefit from strategies using the carbon abundance on Earth.

Advanced Integration of Microwave Kiln Technology in Enhancing the Lost-Wax Glass Casting Process: A Study on Methodological Innovations and Practical Implications

Lost-wax glass casting, an esteemed yet technically demanding art form, traditionally relies on specialized, costly kiln equipment, presenting significant barriers to artists regarding equipment affordability, energy efficiency, and the technical mastery required for temperature control. Therefore, this study introduces an innovative approach by integrating a microwave kiln with standard household microwave ovens, thus facilitating the lost-wax glass casting process. This methodological adaptation allows artists to employ readily available home appliances for glass creation, significantly reducing the process’s cost and complexity. Our experimental investigations reveal that, by using a 500W household microwave oven for heating, the silicon carbide (SiC) in microwave kilns can efficiently absorb microwave energy, allowing the kilns to reach temperatures exceeding 700 °C, a critical threshold for casting glass softening. We further demonstrate that by adjusting the number of heating cycles, producing high-quality, three-dimensional(3D) glass artworks is feasible, even for large-scale projects. In addition, the microwave kiln can be used as an effective cooling tool to uniformly cool the formed casting glass. This study presents a possible alternative to conventional kiln technology and marks a paradigm shift in glassmaking, offering a more accessible and sustainable avenue for artists and practitioners.

Quantifying Ageing of 35-50 and 70-100 Asphalts Using Fourier Transform Infrared Spectroscopy and Dynamic Shear Rheometer Measurements

In this study, Dynamic Shear Rheometer (DSR) and Fourier Transform Infrared (FTIR) spectroscopy tests were performed on 35-50 and 70-100 penetration-graded asphalts. Both tests were performed on specimens at three different ageing states: unaged, short-term aged using the standard rolling thin film oven (RTFO) device, and long term aged by placing RTFO residue in the pressure aging vessel (PAV) apparatus. The tests were accomplished to quantify how ageing affects the results of both tests, namely the complex shear modulus for the DSR test and the carbonyl, sulfoxide, and ageing indices for the FTIR spectroscopy test. Both sets of measurements confirm that the harder asphalt stays harder than the softer asphalt after undergoing ageing, but the rate of hardness is higher for the softer asphalt. For instance, on average, PAV ageing was found to increase the amplitude of the shear complex modulus, from the unaged state, by 4.3 times and by 6.2 times for the 35-50 and 70-100 asphalts, respectively. It was also found that ageing decreases the phase angle for asphalt and the decrease is more pronounced for the softer asphalt (70-100) than the harder one (35-50). This was attributed to more maltenes content in the softer asphalt that transform into asphaltenes during ageing. Correlation coefficient between FTIR signals from the same samples revealed that FTIR spectroscopy as used in this research has an excellent repeatability. The repeatability was also confirmed using measures of dispersion such as the coefficient of variation, which was found not to exceed the 1.2%. The 35-50 asphalt was found to have more C=O and S=O links than the 70-100 asphalt since it showed more absorbance in the carbonyl and sulfoxide bands. These links are thought to make the asphalt physically harder. An analysis of variance study revealed that ageing is a statistically significant factor as measured using ageing indices calculated from FTIR spectroscopy data with the index AIFTIR being the most sensitive to ageing among all considered indices. Empirical power equations with high coefficient of determination values were established to predict DSR results from FTIR index values, which was possible since both types of measurements show the same trend with ageing.

Determination of Soil Moisture for Sandy Soils Using Gas and Microwave Ovens

Since there are several methods used to determine soil moisture, the objective was to compare the moisture values obtained with the use of a gas oven and a microwave to the values obtained with the standard oven method. Having been carried out at the Hydraulics Laboratory of the State University of Maringá, Umuarama Regional Campus, the performance of the methods was evaluated in the determination of five levels of moisture (10, 15, 20, 25, and 30%), with dry masses obtained at 15, 20, 25 and 30 minutes for the gas oven and at 2, 4, 6 and 8 minutes for the microwave. The best drying times were selected using the Taylor Diagram. Linear regression was performed between the methods, in order to obtain the correlation coefficient (r), the Willmott agreement index (d), the performance index (c), absolute error (EA), absolute mean error (ERA), and root mean square error (RQME). By analyzing the results obtained, it can be stated that the gas oven method and the microwave method presented excellent performance when compared to the standard method. It was also concluded that the time of 25 minutes for the gas oven method was efficient and, for the microwave method, the drying time of 8 minutes was sufficient, meaning a reduction in the time for moisture determination.

Effect of Cooking with Superheated (SHS) vs. Standard Steam Oven on the Fatty Acids Profile of Different Kinds of Meat and Fish.

We compared the effect of two different kinds of steam oven-a standard (SO) and a superheated steam (SHS) oven-on four different kinds of samples: hamburgers, bovine steaks, pork steaks, and salmon fillets. Ten samples of each meat/fish were divided into three parts. Then samples were analyzed as (i) raw, (ii) cooked with SO, and (iii) cooked with SHS. For each sample, we determined the proximate composition, fatty acid composition and thiobarbituric acid reactive substances (TBARS). The results of fatty acid composition were processed both with a linear model and with a multivariate approach by using three complementary discriminant analysis techniques: canonical (CAN), stepwise (St) and discriminant (DA). SHS was effective in degreasing hamburgers but not the other kinds of samples. Cooking methods selectively affected the fatty acid profile of samples, SHS being higher in MUFA and lower in PUFA n-3 than SO. This result was also confirmed by the discriminant analysis. Finally, samples cooked with SHS showed a lower fatty acid oxidation extent than SO, as the TBARS value was significantly lower in the SHS than in the SO, irrespective of the type of meat/fish cooked.

DNA Nanostructure-Guided Plasmon Coupling Architectures

DNA Nanostructure-Guided Plasmon Coupling Architectures

Relationship between thermoreversible and irreversible aging in rejuvenated asphalt binder

Rejuvenators are now widely used to restore performance of aged asphalt. A critical factor that controls performance of pavements in service is age hardening of the binder. Hence, both reversible and irreversible processes need to be accounted for in order to ensure durable designs. Thermoreversible processes are affected by irreversible aging, but how the two interact remains largely unexplored for rejuvenated binders. A straight Cold Lake PG 58-28 binder was blended with castor oil residue (COR), soybean oil residue (SOR) and petroleum-based aromatic oil (ARO) rejuvenators. Standard Extended Bending Beam Rheometer (EBBR, AASHTO TP 122) tests were conducted to assess thermoreversible aging. Non-isothermal crystallization kinetics were investigated using Modulated Differential Scanning Calorimetry (MDSC) and Thermogravimetric Analysis (TGA). Standard Rolling Thin-Film Oven (RTFO) followed by 20 h of Pressure Aging Vessel (PAV) conditioning proved sufficient to differentiate thermoreversible aging tendencies. However, EBBR grade losses increased significantly upon extended aging. Rejuvenated compositions fared worse in comparison to straight Cold Lake binder. Three-day grade losses for the PG 58-28 ranged from 1.8 °C (unaged) to 9 °C (100 h PAV). In contrast, the ARO blend lost 0.8 °C (unaged) increasing to a significant 15 °C (100 h PAV).

Evaluation of grain moisture measurement methods suited for developing countries

Cost-effective measurement methods that are feasible for smallholder farmers in developing countries are needed for monitoring stored grain quality. The objectives of this study were to: 1) evaluate six commercially available grain moisture indicators for accuracy and precision, 2) indicate advantages and limitations of each device, and 3) assess the suitability of each method for use in developing countries. Whole kernels of shelled corn, soft red winter wheat, and paddy rice were prepared at various moisture content (MC) levels and measurements followed manufacturer's instructions. Replicated measurements were taken with each method (KSU-GT200, John Deere SW08120, Agratronix MT-16, Dickey-john M3G, Hygrometer, DryCard) at each MC and grain combination. Procedures ensured uniform mixing of each sample. As a reference, MC was determined using a standard oven method. For the DryCard (cards coated with a chemical that reacts to humidity) and hygrometer methods, repeatability was indicated using additional grain samples that were near the critical relative humidity specified by the manufacturer (65% RH). At 14.5%wb moisture content, the John Deere SW08120 measured moisture content of corn with the highest precision. Minimum and maximum differences (%wb MC) from oven results for all grains were 0.1% (KSU-GT200) and 3.7% (Dickey-john M3G), respectively. Measurements for paddy rice at higher MC levels (above 15%wb) were highly accurate (0.1%).

Study on rapid measurement technic of dry rubber content in latex cup lump by electrical properties

Dry rubber content meter is substantial tool for Impartial trade on rubber cup lump. Department of Agriculture researchers proposed rapid measurement technic of dry rubber content in latex cup lumps by their electrical properties. Two probe types needle and roller were designed, in the first phase, constructed, installed and tested. Needle type probe of 25 mm. in length and 5 mm. apart was selected in measuring electrical properties of cup lump samples as its penetration depth is half of the thickness. Two cylindrical rollers probe of 220 mm. in length and 101.6 mm. (4 inches) in diameter powered by 2 HP gear motor were designed, constructed, installed and tested. Rubber cup lump samples were each statistical divided into 9 regularly measuring parts in needle type probe. Rubber cup lump samples in rollers type probe were typically enforced to pass through 1-inch gap between two rollers. Irregular size sample of more than 76.2 mm. (3 inches) thickness of rubber cup were sliced before measuring into 2 equal thickness pieces. Electrical properties of samples were acquired by standard electrical measuring instruments and percentage of dry rubber content were determined by standard oven method for all sample segments. As the results of this study, rubber content percentage of cup lump was correlated with electrical capacitance than resistance. Electrical capacity value of the latex cup lump from needle-type and two roller-type probes were inversely correlated with the percentage of dry rubber content within the range of 0 – 75 nF and 0 – 380 nF and coefficient of determinations were 0.90 and 0.97, respectively. These initiate features will be utilized in designing of percentage of dry rubber content prototype meter by electrical property values in the future. Percentage of dry rubber content from DRC method of lump from fresh latex and conventional cup lump by oven method was significantly correlate. Electrical properties of latex cup lump produced in the laboratory and farmers are also significantly consistent.

Laboratory-Scale Integrated Coke Dry Quenching System for Coal Carbonization Test

Carbonization test using pilot coke oven is an important laboratory-scale analysis to evaluate coke-making ability of metallurgical coals. RDCIS, SAIL, comprises a pilot oven of 250 kg coal charging capacity, with the facility of both top and stamp chargings. The functional pilot coke oven of this size for carbonization test is expensive and requires a large number of samples and time. To prevail over these limitations, a small-scale carbonization equipment was designed and developed in RDCIS. Experiments were conducted in both standard pilot ovens and newly developed carbonizations test equipment, namely integrated dry quenching system, and results were compared. Strong correlations were found between test results obtained from both the apparatus. This paper expatiates the basic outline of the equipment, basis of design, and results obtained from the carbonization tests using this equipment.

On the self-heating behavior of upgraded biochar pellets blended with pyrolysis oil: Effects of process parameters

Biochar obtained from biomass pyrolysis is a promising carbon neutral material which can be used in substitution of fossil coal and coke in metallurgical applications. Biochar’s mechanical properties improve significantly without compromising reactivity, when upgraded by densification with pyrolysis oil and reheated. However, upgraded biochar pellets use in the industry is limited due to the risks associated with self-heating. This issue must be seriously considered for further industrial production of upgraded biochar pellets. Self-heating oven tests are generally time-consuming and limit the possibility of testing various potential solutions. The aim of this work was both to investigate the self-heating behavior of densified biochar and to possibly substitute the standard oven test with a fast and cost-effective thermogravimetric analysis. This was done by using Response Surface Methodology, where pyrolysis temperature, oil content and treatment temperature were selected as independent variables. By statistical analysis it was possible to understand that self-heating risk can be drastically reduced by upgrading the pellets at high temperatures (i.e. re-heating). In addition, through the analysis of the initial combustion temperature, the maximum weight loss rate and the activation energy (considered as responses of the model), it was possible to understand how to predict the results of the self-heating oven tests through thermogravimetric analysis.

Osmo-solar drying of bottle gourd (Legeneria Siceraria)

The bottle gourd is a common vegetable in India subcontinental. Osmotic dehydration increases the storage ability of fruits and vegetables making them available throughout the year. Dehydrated products also play a great role in processed foods of all kinds and the way to achieve high quality dehydrated products are desired. The combination of osmosis with solar drying has been put forward, mainly for tropical fruit. A 24-hour cycle has been suggested combining osmodehydration, performed during the night, solar drying during the day. The well washed bottle gourd fruits were then peeled off with help of stainless-steel hand peeler. Pieces of bottle gourd cubes (1cmx1cmx1cm) were then cut out using a ruler and knife. The salt solution with 5, 10, 15, 20, and 25% (w/w) concentration were prepared. Bottle gourd cubes were immersed in the osmotic reagents with a fruit to osmotic solution mass ratio of 10:1, 20:1 and 30:1 soaking experiments were conducted at 400C, 500C and 600C in a 500 mi capacity water bath. The osmotic dehydration was done for a period of 1, 3, 5, 7 and 9 h and replicated thrice. The dependent variable studied was moisture content after dehydration. Moisture content of sample was determined by standard air oven method (Ranganna, 1995). The minimum moisture content was 46.9% (wb) for samples osmotically dehydrated at 600C for 9 h at 30:1 fruit to osmotic solution at 25% concentration. The moisture content of bottle gourd cubes observed decreases with higher concentration, temperature and mass ratio. Solar drying characteristics of 9 h bottle gourd cubes at 600C are determined by solar tray dryer. During the process of solar drying of 9 h bottle gourds cubes, the air temperature inside the cabinet varies 44 to 810C. and relative humidity inside the chamber was measures 34 to 58 percent. The minimum value of final moisture content of osmo-solar dried bottle gourd cubes was 8.3% at 600C for sample of 10:1 mass ratio and maximum value of final moisture content was 24.4% of at 600C for 30:1 sample.

Pet Şişe Şişirme Makinelerinde Fırın Optimizasyonu

In this study, we have consulted the information of Pet Bottle Machine manufacturers and end users; Located in a limited number of Pet Bottle Blowing Machines in Turkey has been conducted on ovens. After the preform moves around its axis since it enters the machine and reaches the required heat by passing through the oven sections, bottles are obtained by giving 40 bar high pressure in the blowing unit. The quality of the obtained bottles is very important. The reason for this is that the labeling, filling and palletizing machines are also included in the continuation of Pet Bottle Blowing Machines. If the bottles are of poor quality, the entire line stops. The most important way to ensure that the bottles are produced in a robust manner is the efficient heating of the preforms, the raw material of the bottle. This study provided more efficient application of heat treatments of prefoms. In the heat treatment of the preform, to optimize the oven zone; PLC, HMI, temperature controls, thermal heat meter, thermocupl and thermal camera are used. The instantaneous temperature values obtained from the thermal heat meter, thermocupl and temperature controls are processed to the PLC as a reference and necessary adjustments are made available to the user via HMI. The reference values imported to PLC were developed using ST language in Codesys based software. In this study, instant values are shown on the panel. By using these data, heat optimization of infrared lamps in Pet Bottle Blow Molding Machines despite variable weather conditions is provided. The heat taken from the oven, the preform which is the raw material of the bottle, which has been optimized by the software, is observed with the thermal camera; The results were compared with the standard oven. In the context of the data obtained, it was observed that the software positively affected the preform and caused the production of bottles of better quality and cost-effective which are not affected by the changing climate conditions.

Behaviors of asphalt under certain aging levels and effects of rejuvenation

Aging has an undesirable effect on asphalt properties, which can be restored by rejuvenation. In this study, neat asphalt was aged by the standard rolling thin-film oven (RTFO) test with varying times to obtain asphalts at different levels of aging; these asphalts were then rejuvenated to their original penetration grade. Analysis of the asphalt fractions, Fourier-transform infrared spectroscopy (FTIR), and atomic force microscopy (AFM) were employed to investigate the evolution of the distributions of SARA fractions, the functional groups, and the microstructures during aging and rejuvenation. Physical and rheological properties were tested to evaluate the pavement performance of the asphalts. The results showed that aging can convert the aromatics to resins and further to asphaltenes, and increase the carbonyl and sulfoxide contents due to oxidation. Consequently, the micelle number and proportion in the colloidal structure increased at the micro-scale, and the penetration and ductility decreased while the softening point increased at the macro-scale. These trends were more evident at increased aging levels. A rejuvenator with a high content of aromatics can adjust the fractions and dilute the aggregated micelles in aged asphalt, thus achieving the thermodynamically reversible process of the asphaltenes and resins being converted to saturates and aromatics; this balances the fraction distribution and restabilizes the colloidal structure. The performance-related properties were basically restored to their unaged levels. Comparing the results of the aged asphalts from the laboratory and field, the ductility and asphaltene content of the latter cannot be restored to their original level, though other properties can be, which indicates the complex service conditions of asphalt in the field.

Evaluation of baking performance by means of mid-infrared imaging

The present work aims to validate mid-infrared imaging as a promising method for evaluating oven systems. Therefore, a novel approach by analyzing mid-infrared radiation patterns captured by a thermal camera and subsequent image processing was developed. A thermal camera was adapted to two different oven systems: a standard electric deck oven and a novel gas-fired baking oven with integrated volumetric ceramic burners (VCBs). The baked goods were analyzed and key indicators describing the final product quality were determined. Specific volume, surface browning and mid-infrared image processing demonstrated a comparable performance of both oven systems. Furthermore, the determined surface heat homogeneity of the items to be baked was 0.65 ± 0.05 (–) for the electronic oven and 0.70 ± 0.03 (–) for the VCB oven. The proposed approach proved its fundamental qualification for comparing and evaluating different oven systems.

Selective heating and enhanced boiling in microwave heating of multicomponent (solid–liquid) foods

AbstractSelective or enhanced heating of a solid in a solid–liquid mixture in microwaves that can lead to enhanced boiling and possibly bumping was studied. A soup containing broth and particulate foods was heated in a cylindrical container in a standard domestic microwave oven. Heating patterns were obtained using a coupled three dimensional thermal‐electromagnetic model, as well as an infrared camera, and boiling was visually observed. Selective heating of the solid particulates over the broth depends on their dielectric and thermal property differential. Enhanced and early boiling on the surface resulting from selective heating also depends on factors that aid in bubble formation and growth such as the surface roughness and porosity (gas pockets) in the solid. For quick prediction of the potential for enhanced heating in product design, a characteristic number was developed that can predict situations that are more prone to enhanced heating than the surrounding liquid.Practical applicationsWhen microwave heating of a soup or a soup‐like multicomponent mixture of solid and liquid foods, for example carrot or corn pieces in a broth, the solid can end up heating faster than the surrounding liquid, leading boiling to be initiated preferentially at the solid surface, as opposed to in the bulk broth. Depending on the solid material and its surface properties, such a boiling can be further enhanced and sudden, leading to possible bumping during the heating process. A simple design parameter, based on easily available dielectric and thermal properties of the solid and liquid, was developed to quickly predict the possibility of such an enhanced heating of the solid surface (that could eventually lead to bumping). When designing microwaveable products like soups, this simple parameter can be of particular help, reducing the time and resources for experimentation by providing a quick estimate of the probability of enhanced boiling and thus bumping.

Understanding the short-term aging of warm mix asphalt using rolling thin film oven

Standard Rolling thin film oven (RTFO) test at 163°C for 85 minutes has been investigated and revised to represent the short-term aging of the warm mix asphalt (WMA) binder which is mixed and aged at lower temperature. Because of wide mixing temperature and variation in duration of storage and paving time, field short-term aging differs significantly. To simulate the reduced aging of WMA binders in the laboratory, series of RTFO tests were conducted on two binders at three different temperatures and for four aging periods. Short-term oven aging (STOA) of mix was performed for the same time duration at those three RTFO aging temperatures. A RTFO aging model was developed correlating the rheological properties of STOA mix. Following the aging model developed in this study aging temperature and duration can be selected for RTFO testing to simulate aging effect that a binder experiences in STOA of mix. It is observed that the change in aging index of binder follows a linear relationship with aging time, and the rate of change of the aging index changes linearly with temperature. This study also affirms that STOA of mix exhibits more sensitivity to temperature than that of RTFO aging of binder. Investigation of plant and laboratory mix depicts that very small portion of mix aging occurs during mixing phase however, main portion of short-term aging occur during the storage of plant mix or oven aging of laboratory mix. Because of wide mixing temperature RTFO aging test protocol need to be adjusted.

Exchange bias and diffusion processes in laser annealed CoFeB/IrMn thin films

The performance of exchanged biased tunnel junctions strongly relies on the annealing process finalizing the fabrication process, which is applied to set a pinned reference magnetization, as well as to enhance the magnetoresistance ratio through the crystallization of the CoFeB layers. With the increasing demand in terms of integration and scalability of tunnel magnetoresistive elements, a laser-induced annealing process presents several advantages against traditional oven annealing technique. It provides the possibility to locally set an individual reference magnetization at the micrometer scale to enable e.g. a Wheatstone bridge or multidimensional sensor fabrication on a wafer level. This study presents the influence of laser-induced localized annealing on the magnetic properties of an exchanged biased CoFeB/IrMn system. The diffusion processes occurring at the interface of CoFeB/IrMn are analyzed in detail utilizing X-ray photoemission spectroscopy depth profiling technique and the results are compared to those obtained by standard vacuum oven annealing and correlated to the magnetic properties investigated by magneto-optical Kerr effect magnetometry.