Drying Time Research Articles

Impact of an educational intervention on hand hygiene practice among nursing students, with a focus on hand drying efficacy.

Hand hygiene and its significance for reducing the spread of infection is well evidenced and has been brought into sharp focus following the COVID-19 pandemic. Although a crucial clinical skill in ensuring safe healthcare, little is known regarding nursing students' effectiveness of hand hygiene practice. The aim of this study was to evaluate the impact of an educational intervention on hand hygiene practice, designed by the research team for first year pre-registration nursing students. Particular emphasis was placed upon hand drying technique and time. 825 nursing students were observed and assessed for their hand hygiene practice in a clinical suite at a university setting. Nursing students were observed for compliance against set outcome measures involving hand hygiene preparation, hand and wrist washing technique, hand drying technique and time. Data were analysed quantitatively using SPSS. The educational intervention had a significant impact on the clinical skills learning of nursing students. 779 students passed the assessment at the first attempt (94.4%). Of the 46 students that failed to meet the necessary criteria, 45 satisfied the criteria at the second attempt; giving an overall optimal compliance of 99.9%. 99.6% of students complied with recommended hand drying standards. This study offers an important contribution to the development and delivery of nursing education programmes. The educational intervention improved compliance with recommended hand hygiene technique and practice. Lack of attention to hand drying may negate effective hand hygiene in healthcare.

PHYTOCHEMICAL SCREENING, FORMULATION AND EVALUATION OF FOOTSPRAY CONTAINING HONEY PINEAPPLE PEEL EXTRACT (ANANAS COMOSUS [L.] MERR)

Foot odor or bromhidrosis occurs due to the activity of bacteria that convert leucine in sweat into isovaleric acid which results in unpleasant odors. Honey pineapple skin (Ananas comosus [L.] Merr) is generally waste, whereas honey pineapple skin is known to contain antibacterial compounds. The aim of this study is to determine the potential of honey pineapple peel as an active ingredient in footspray based on the results of phytochemical screening and physical evaluation. Honey pineapple peel was extracted by maceration method using ethanol 70% then phytochemical test. Footspray preparations were made with various extract concentrations of 0%, 25%, 35% and 45% then tested for organoleptic, pH, specific gravity, viscosity, homogeneity, spreadability, and dry time during storage period of 0, 7, 14 and 21 days at room temperature. This study showed that honey pineapple peel extract contained flavonoids, tannins, phenols and alkaloids. The footspray has brown color with honey pineapple scent, pH of 5.71-6.37, specific gravity 1.05-1.09 g/mL, viscosity 7.2-13.2 cP, spreadability 6.67-7.60 cm, and the dry time is 4-5 minutes. Footspray containing honey pineapple peel extract with concentrations of 25%, 35% and 45% has a pH value that is safe for the skin, with good specific gravity, viscosity, homogeneity and spreadability, also stable during storage. Formula 1 (25% extract concentration) tends to be preferred because its texture is soft and not too sticky when applied to the skin when compared with formula 2 and 3.

Deterioration mechanism of loess from Ili valley region of China under wet and dry cycles: evidences from shear tests

The properties of loess in the Ili region of China are significantly affected by repeated cycles of rainfall and evaporation. It is thus essential to investigate the deterioration mechanism of loess subjected to the wet and dry cycles. This paper employs various methods, including the direct shear and triaxial shear tests, as well as the scanning electron microscopy (SEM), to evaluate the variation patterns of shear strength parameters and microstructure of Ili loess. The direct shear test was conducted on loess samples experiencing a limited number of wet and dry cycles (0, 1, 3, 5, 7, and 9), while the triaxial shear test focused on a more extensive range of wet and dry cycles (0, 1, 3, 10, 20, and 30). In parallel, the alterations in the shear strength parameters of the loess material under different shear tests were also scrutinized. The findings obtained from this research revealed that the shear strength of Ili loess decreased to varying degrees based on the two test methods when they are affected by the wet and dry cycles. Comparing the results with the same number of wet and dry times (0, 1 and 3 times), both the shear strength and cohesion obtained from the triaxial shear test were greater than those from the direct shear test, while the results for the angle of internal friction were reversed. Moreover, the scanning electron microscope tests on Ili loess did indicate that the micro-particle size, pore space, morphology, soil structure, and particle contact mode exhibited the deterioration with different degrees. The micro-structural change is believed to be the main reason for the deterioration mechanism of the shear strength. The research outcomes will enrich the understanding about the loess properties in Central Asia, providing data reference and theoretical basis for engineering construction in these region.

Effect of the drying type on the properties of granules and tablets produced by high shear wet granulation

Although high shear mixers can represent a single-pot process, separate drying equipment is commonly employed. Limited literature exists on the use of a heating jacket coupled with a vacuum pump typically used in a single-pot setup, so this study compares the drying effects of a single-pot setup (DSP) and ventilated oven (DVO) on the properties of granules and tablets. Granules containing three actives of varying water solubility were produced and characterised. The results showed that DSP reduced the drying time and produced smaller, irregular, and weaker granules with different compression mechanisms. The tablets were produced and characterised. All tablets passed the uniformity test. Compression differences had no impact on tablet properties for poorly water-soluble actives, but altered properties for highly soluble actives due to increased active migration and crystallization on the granule surface. In conclusion, while DSP offers advantages, careful consideration of the drying technique is essential during product development.

Optimization and modeling of vacuum impregnation of pineapple rings and comparison with osmotic dehydration.

The vacuum impregnation (VI) process parameters (vacuum pressure=20-60kPa; VI temperature=35-55°C; concentration of the sucrose solution=40-60°Brix; and vacuum process time=8-24min) for pineapple rings were optimized based on the moisture content (MC), water loss (WL), solids gain (SG), yellowness index (YI), and total soluble solids (TSS) content of pineapple rings using response surface methodology (RSM). A relationship was developed between the process and response variables using RSM and artificial neural network (ANN) techniques. The effectiveness of VI was evaluated by comparing it with the osmotic dehydration (OD) technique. The optimum condition was found to be 31.782kPa vacuum pressure, 50.441°C solution temperature, and 60°Brix sucrose concentration for 20.068min to attain maximum TSS, YI, SG, and WL, and minimum MC of pineapple rings. The R2 values of RSM models for all variables varied between 0.70 and 0.91, whereas mean square error values varied between 0.76 and 71.58 and for ANN models varied between 0.87-0.93 and 0.53-193.78, respectively. Scanning electron micrographs (SEM) revealed that parenchymal cell rupture was less in VI than in OD. The VI pineapple rings exhibited more pores and high SG, as compared to OD, due to the pressure impregnation. Spectroscopic analysis affirmed that the stretching vibrations of intermolecular and intramolecular interactions were significant in VI as against OD. The VI reduced the drying time by 35% compared to OD, with the highest overall acceptability score and lower microbial load during storage. PRACTICAL APPLICATION: Pineapple is a perishable fruit, which necessitates processing for extended shelf life. This study highlights the potential of the vacuum impregnation process as a promising alternative to conventional preservation methods such as osmotic dehydration for pineapples.

Comparative and comprehensive experimental analysis: Performance variation of a novel hybrid dryer

Conventional energy sources are integrated into solar dryers to allow them to operate day and night. Unlike previous applications, this work presents a novel hybrid dryer in which an external geothermal heat exchanger unit is integrated into an indirect solar dryer to overcome this problem. The tomato drying performance of the hybrid dryer was compared with a solar dryer and conventional shade drying in simple and ventilated modes. The proposed dryer's energy, exergy, and economic performance were evaluated using solar and geothermal energy. During the same period, the hybrid dryer reduced the samples to at least 3.64 times lower moisture content in simple mode than other dryers. In ventilated mode, this value was 2.97 times. Integration of ventilation into the hybrid dryer reduced average drying time from 64 to 56 h, specific moisture extraction rate from 0.63 to 0.60 kg/kWh, specific energy consumption from 3.94 to 2.78 kWh/kg, and payback time from 0.22 to 0.17 years. However, it increased the thermal and exergy efficiency of both dryers' solar air collectors by over 30 % and 27 %, respectively. As a result, the hybrid dryer continued the drying process even when there was no sun and achieved a significant advantage in drying tomatoes compared to the other two drying types. The proposed system will make locations where geothermal energy is available attractive for food drying.

Effects of Photoinitiators on Curing Performance of Wood Wax Oil Coating on Wood

With the increasing shortage of petroleum resources and the growing seriousness of environmental pollution, the exploitation and application of bio-based coatings derived from renewable resources have become increasingly important for the woodworking industry. Wood wax oil (WWO) is a new type of bio-based natural coating material that offers an eco-friendly solution for wood protection. This paper focused on the utilization of tung oil and beeswax as the primary raw materials for the preparation of wood wax oil. The WWO was based on the oxidation polymerization of tung oil, which served as the foundation for the preparation process. The effects of the photoinitiator TPO-L on the curing performance of the WWO were investigated, and the curing mechanism of the WWO system induced by photoinitiators was analyzed and characterized by infrared spectroscopy. Through ultraviolet irradiation experiments and coating quality tests, the effects of incremental photoinitiators on the properties of the surface drying time, gloss, color, hydrophobicity, and solution resistance of the treated ash wood were studied. The results indicated that the addition of photoinitiators was beneficial for the rapid polymerization of wood wax oil. A UV light intensity of 30 w was found to be sufficient to initiate the curing process. Specifically, when using TPO-L as the initiator at a concentration of 3 wt%, the surface could be surface-dried within 10 min under UV exposure. Under these curing conditions, wood wax oil coatings based on tung oil with comprehensive curing properties can be obtained. Additionally, adding 6% beeswax to the tung oil can effectively enhance the hydrophobicity of pure tung-oil-based wood protective coatings.

Effects of different pretreatment techniques on the color indexes, drying characteristics and rehydration ratio of eggplant slices

This study aimed to examine the influence of microwave pretreatment (MWP) for 0, 15, 30, 45, and 60 s, and ultrasound pretreatment (USP) for 0, 5, 10, 15, and 20 min, on the drying time, effective moisture diffusivity (Deff), rehydration rate, color indexes (lightness, redness, and yellowness), and total color change (ΔE) of eggplant slices during dehydration in a hot-air dryer. The results demonstrated that USP significantly reduced the drying time (higher water loss) of eggplant slices (p < 0.05). While, the MWP significantly increased the drying time of eggplant slices (p < 0.05). The Deff values of ultrasonic pretreated slices were considerably higher than those of untreated eggplant slices (p < 0.05). The Deff determined by Fick's second law was varied from 5.95 × 10−10 to 9.56 × 10−10 m2s−1, and from 1.27 × 10−9 to 1.42 × 10−9 m2s−1, for samples pretreated by microwave and ultrasound, respectively. Nine mathematical models (Page model, Quadratic model, Newton model, Verma model, Logarithmic model, Two-term Exponential model, Wang and Singh model, Henderson and Pabis model, and Midilli model) were used to estimate the drying coefficients by following the non-linear regression method. The results showed that the Page model became the most accurate model to show the drying characteristics of eggplant slices compared to eight other confirmed mathematical models with sum of squared error (SSE) values ranging from 0.0014 to 0.0098. The average rehydration ratio of untreated, microwave-treated, and ultrasound-treated eggplant slices were 404.6 %, 360.1 %, and 438.6 %, respectively. The redness, yellowness, and ΔE parameters of pretreated samples by microwave were higher than the untreated slices. It can be concluded that USP proved to be effective in retaining surface color and improving drying speed of eggplant slices compared to MWP. The results showed that the ultrasonically pretreated eggplant slices had shorter drying times, improved Deff values, higher rehydration rates, and appropriate appearance.

Process and quality parameters of convective dried yacon: Influence of ethanol treatment

Yacon is a highly perishable tuberous root, rich in fructooligosaccharides (FOS). Convective drying preceded by ethanol treatment (ET) is an alternative for increasing shelf life in a shorter process. The aim of this study was to investigate the impact of ET and temperature (50 °C and 70 °C) on quality parameters (fructan retention, total phenolic content, antioxidant capacity, shrinkage, color and microstructural parameters) and process parameters (drying time, drying kinetics, and energy consumption) in the convective drying of yacon slices. The ET induced structural alterations in the tissues and cells that aids in the reduction of drying time up to 28.00 %. ET resulted in an increase in effective diffusivity and leaded to noteworthy reduction in energy consumption (up to 22.72 %). The quality parameters such as color, shrinkage, and total phenolic content showed no significant differences among the treatments. The use of ethanol promoted highest preservation of antioxidant activity; however, it caused degradation of FOS. The ethanol pretreated drying at 50 °C was the better condition for lower consumption and preservation of quality parameters as total phenolic content, antioxidant capacity and fructan retention, but the samples dried at 50 °C were the ones with the highest fructan retention (55.11 ± 2.19 %).

Evaluation of Low- and Intermediate-Temperature Cracking Performance of Fiber-Reinforced Asphalt Mixtures

This study was conducted to assess the impact of aramid fiber reinforcement on the fatigue and thermal cracking performance of asphalt mixtures at intermediate and low temperatures, respectively. The study also involved evaluating the experimental consistency and ranking fiber-reinforced asphalt mixtures (FRAMs) based on their performance. One aggregate (diabase stone), one binder type (PG 76-22), and two combinations of aramid fibers, added at different dosages, were used to produce three FRAMs. These fibers included polyolefin/aramid (PFA) fibers at 0.05% dosage by mix weight and Sasobit-coated aramid (SCA) fibers at 0.01% and 0.02% dosages. An unreinforced (control) mix was also produced without any reinforcement. All mixtures were produced at a batch plant by keeping their binder content constant (at 5.5%). The manufacturer recommended dry and wet mixing times were used for better fiber distribution and represent actual mixing conditions. The laboratory performance of plant-produced FRAMs was assessed to characterize the low- and intermediate-temperature cracking performance. The indirect tension asphalt cracking test, semi-circular bend test, three-point bending beam tests, and uniaxial fatigue tests were performed at intermediate temperature; the disk shape compact tension test and thermal stress restrained specimen test tests were performed at low temperature. Fibers were successful at improving the fatigue cracking of asphalt mixtures based on intermediate-temperature testing results. In addition, fiber reinforcement, regardless of dosage and combination, showed improvements in low-temperature (thermal) cracking performance. Furthermore, based on ranking analysis for selected performance indicators from each experiment, the SCA 0.02% reinforced mix on average showed the highest cracking resistance.

Effect of direct addition of asphalt rubber pellets on mixing, performance and VOCs of asphalt mixtures

Direct injection modifiers revealed vast development potential because of their convenience utilization and no need for professional equipment. However, different characteristics of each direct injection modifier fluctuate significantly on the mixing process and road performance of their modified asphalt mixtures. The purpose of this paper is to evaluate the effectiveness of two novel asphalt rubber pellets (ARP) and asphalt desulfurized rubber pellets (ADRP) in improving the performance of asphalt mixtures. Firstly, this paper used orthogonal experimental design method to determine the priority order of the influencing factors on direct injection modifiers (ARP and ADRP), and further optimized the mixing technology of asphalt mixtures containing direct injection modifiers. Then, using base asphalt, commercial asphalt rubber (AR) and SBS (styrene-butadiene-styrene block copolymer) modified asphalt as control groups, the road performance of five asphalt mixtures was evaluated. Finally, the volatile organic compounds (VOCs) release characteristics of the asphalt mixtures were quantitatively analyzed. The results indicated that the priority order of factors affecting the ARP and ADRP is digestion time > dry mixing time > mixing temperature, and the optimal mixing process parameters are dry mixing for 90 s, mixing temperature of 180 °C, and digestion time of 90 min. Additionally, road performance of ADRP modified asphalt mixtures (ADRP-AM) is superior to that of ARP modified asphalt mixture (ARP-AM), which reaches or even exceeds the road performance of asphalt rubber mixtures (AR-AM) and SBS modified asphalt mixtures (SBS-AM) prepared by wet process. The five asphalt mixtures demonstrate the similar VOCs composition, and the total concentration of VOCs emissions is ARP-AM > AR-AM > ADRP-AM > B-AM > SBS-AM. P-/m-xylene, acetone, benzene, ethylbenzene and substances containing chlorine emerge high concentration for the VOCs composition of the five asphalt mixtures. This research can provide technical support for promoting the widespread application of direct injection asphalt rubber pellets.

Chemical Composition and Sugars Profile of Aswan’s Dry Dates Varieties as Affected by Sun Drying, Storage and Harvesting Time

Chemical Composition and Sugars Profile of Aswan’s Dry Dates Varieties as Affected by Sun Drying, Storage and Harvesting Time

Investigation of volatiles and quality attributes of indica-japonica hybrid paddy by radio frequency combined hot air drying

The study was aimed at investigating the effects of radiofrequency combined hot air drying (RF-HAD) on volatiles and quality attributes of indica-japonica hybrid paddy. The results indicated that RF-HAD reduced the drying time by 40% compared to hot air drying (HAD). In addition, HA-RF-dried samples showed significantly higher color, vigor, and taste value but less fatty acid value than HA dried-ones. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed that RF-HAD did not affect the protein profile of rice protein. Gas chromatography-ion mobility spectrometry characterized changes in volatile components of paddy before and after drying, results showed that the content of aldehyde and ester aromatic compounds increased after drying and the content of most volatile components in RF-HA-dried paddy was higher than in HA-dried samples. Thus, the inference was that RF-HAD technology may be an innovative alternative to existing drying methods such as microwave, HA, and other drying technologies.

Morphological And Quality Parameters Of Chrysanthemum Flowers As Influenced By Different Pre-Drying Treatments And Drying Methods

In the present study the flowers of chrysanthemum cv. Baggi were subjected to four different pre-drying treatments i.e. P0 – Control (Soaking in Distilled water for 15 minutes); P1 – Soaking in Citric acid (2%) for 15 minutes; P2 – Soaking in Magnesium Chloride (10 %) for 4 hours; P3 – Soaking in Glycerol: water (1:3) for 24 hours and five drying techniques i.e. D0 = Air drying at room temperature without embedding; D1 = Embedded drying in Silica gel in a hot air oven at 50+5 °C; D2 = Embedded drying in Silica gel in a microwave oven; D3 = Embedded drying in Borax in hot air oven 50+5 °C and D4 = Embedded drying in Borax in microwave oven in a factorial completely randomized design. Pre-drying treatment, Glycerol and Water in a 1:3 ratio proved best which resulted in a maximum dry flower weight of 0.83 grams, a minimal moisture loss of 67.45%, a maximum dry flower diameter of 4.24 centimeters, and a minimal reduction in diameter of 0.37 centimeters besides, a minimal drying time of 71.43 hours. In terms of quality parameters, the flowers treated with glycerol and water (1:3) had the highest scores for color (3.82), texture (2.76), shape (3.65), non-shattering of petals (3.87), and overall acceptability (3.64). Silica gel embedded flowers and drying them in a hot air oven resulted in a smaller reduction in diameter (0.20 centimeters) and achieved the highest scores for color (4.39), texture (4.18), shape (4.30), non-shattering of petals (4.20), and overall acceptability (4.54). The combination of the glycerol: water pre-treatment and the silica gel with a hot air oven drying method showed the least reduction in diameter (0.23 centimeters) and the highest scores for color (4.75), texture (4.60), shape (4.60), non-shattering of petals (4.55), and overall acceptability (4.75). Drying the flowers in a microwave oven with either desiccant resulted in the shortest drying time of 0.10 hours. On the other hand, air drying without embedding the flowers produced the lowest dry flower weight (0.46 grams), the highest percentage of moisture loss (82.44%), the smallest dry flower diameter (3.57 centimeters), and the largest reduction in diameter (1.00 centimeters). However, air drying took the longest time at 328.93 hours and resulted in dried flowers that were deemed unacceptable with minimal scores for color (2.70), texture (1.35), shape (1.95), and overall acceptability (2.35).

Formulation and Evaluation of Serum Gel from Sengkubak Leaf Extract (Pycnarrhena Cauliflora Diels)

Background: Serum has a high concentration but a low viscosity. a facial serum that has a fairly good ability to absorb into the skin, releases the active substance of the serum well and is easy to apply to the face. Sengkubak (Pycnarrhena cauliflora Diels) is a type of plant in the Menispermaceae family which can be found in West Kalimantan. Sengkubak also has good potential to be developed as a source of antioxidant compounds Objectives: Knowing the optimal formulation of sengkubak leaf extract serum gel (Pycnarrhena Cauliflora Diels) and knowing the evaluation of the physical properties of Sengkubak leaf extract serum gel (Pycnarrhena Cauliflora Diels) Method: The study used a quasi-experimental design method with varying concentrations of 1 gram, 1.5 grams and 2 grams of natrosol. Serum gel was evaluated for physical organoleptic, homogeneity, spreadability, dry time, adhesion, pH, and viscosity. Results: The results of the observations on the viscous liquid organoleptic test and on the homogeneity test of homogeneous preparations. the most optimal spreadability test results were formulation 1, the most optimal drying time was formulation 1. the most optimal adhesion test results were formulation 1, the most optimal ph test results were formula 1, and the most optimal viscosity test were formulation 2. Conclusion: The most optimal serum gel of sengkubak leaf extract (Pycnarrhena Cauliflora Diels) is formulation 1, with a concentration of 1 gram.

Evaluation and Test of Activity of Anti-Acne Peel-Off Mask Preparation Formulation of Brotowali Stem Extract (Tinospora crispa L.)

Background: Facial skin care for acne treatment is better formulated in topical form, this is due to the duration of the active substances that interact with the skin. One dosage form is a peel-off mask with active substances brotowali stems which contain flavanoids, tannins, alkaloids as antibacterial causes acne. Objective: Analyzing the effect of variations in the concentration of brotowali stem extract (Tinospora crispa L.) on physicochemical evaluation and antibacterial activity of optimal anti-acne peel-off mask preparation formulations Methods: The research method used is True Experimental with a posttest only control group design research design. Make peel-off mask formulations with variations in extract concentrations of 20%, 30%, and 40%. The evaluation then includes organoleptis, homogeneity, dispersion, adhesion, dry time, pH, viscosity, and antibacterial activity tests, statistically analyzed using One Way ANOVA Results: Qualify in the organoleptis test is formula II (30%) and III (40%), the dispersion test is formula I (20%) and II (30%) with a p-value of 0.022, the adhesion test of all formulations with a p-value of 0.014, the dry time test of all formulations with a p-value of 0.000, the pH test is formula I (20%) with a p-value of 0.000, the viscosity test is formula II (30%) with a p-value of 0.000. The diameter of the formula's third inhibitory zone against propionibacterium acnes was 8.61mm ± 0.19 respectively; 14.31mm ± 3.88, and 15.54mm ± 4.80 with a p-value of 0.012 Conclusion: Variations on concentration of brotowali stem extract have an influence on physicochemical evaluation and antibacterial activity, the most optimal formulation is formulation II (30%)

Drying model based on the relative humidity profile of thin-layer tomatoes in an indirect solar dryer

This work defined the development of a model for thin-film drying of tomatoes using an indi-rect solar dryer. Drying experiments were carried out and the drying model was approximated by a simplified model determined by the measurements collected during the experiments, in particular, the measurement of the relative humidity of the tomato during two days of drying coupled with the thermal behaviour of the drying device in free convection. The results show that with good measurements, it is possible to approximate the drying characteristic curve by a linear model with very high statistical performance indicators. The experiments also show that depending on the drying process adopted, the water behaviour of the tomato can change. In addition, the thin-film drying model adopted made it possible to assess the solar drying kinetics of the tomato variety studied. The results obtained finally show that the dryness of the tomato is reached after about 14 hours of drying. The drying temperature reaches an average of 80°C, and the final product water content after the optimal drying time is about 0.40 kg.water/kg.ms on a dry basis. At the end of this study, we concluded that the drying air temperature represents the most important parameter affecting the drying kinetics. The very good agreement between the experimental and numerical results obtained shows that the theoretical model and assumptions used are acceptable, and that our calculation model is reliable.

Effect of Sonication and Edible Coating on Total Phenolic Content, Antioxidant Capacity, and Physical Characteristics of Infrared-Dried Sweet Cherries

This research studied the influence of combined ultrasonic (40 kHz, 150 W, for 3 min) and 0.2% xanthan gum (XG), guar gum (GG), and wild sage seed gum (WG) coating pretreatments on total phenolic content, antioxidant activity, drying time, effective water diffusivity coefficient ( D eff ), rehydration ratio (RR), total color difference ( Δ E ), and surface shrinkage (SS) of infrared-dried sweet cherries. The ultrasonic pretreatment increased the water transfer rate and water diffusivity during infrared drying and decreased the drying time of fresh sweet cherries. The edible coating enhanced the total phenolic content, antioxidant activity, dehydration time, and RR and decreased the D eff , Δ E , and SS values of infrared-dried sweet cherries. The highest value of total phenolic content (3469.7 μg galic acid/g dry) was recorded for pretreated sweet cherry samples by GG. The mean antioxidant activities for uncoated, XG-coated, GG-coated, and WG-coated sweet cherries were 35.64, 59.88, 54.38, and 61.19%, respectively. In this study, the sweet cherry D eff varied from 2.23 × 10 − 9 m2/s (for untreated cherries) to 5.00 × 10 − 9 m2/s (for sonicated and uncoated cherries). The experimental data for the drying curves were fitted to various single-layer equations, and the Page equation using the experimental constants best described the drying rate of sweet cherries. The mean Δ E values for uncoated, XG-coated, GG-coated, and WG-coated sweet cherries were 15.11, 9.91, 8.74, and 10.69, respectively.

Study on the Degradation of SOFC Anodes Induced by Chemical and Electrochemical Sintering Using EIS and µ-CT

The goal of the present study was to quantify degradation phenomena on anodes that can be attributed to chemical (thermal) and/or electrochemical sintering, to find out the underlying mechanisms, and to propose countermeasures. The samples were thermally aged for times from 0 to 1000 h, and additional samples of the same type were subjected to electrochemical loading over the same period. The cells were then examined for microstructural changes using FE-SEM/EDS and micro-computed tomography (µ-CT), and the results are correlated with electrochemical impedance spectroscopy (EIS) parameters of long-term electrochemical experiments under dry and humid conditions. It has been shown that it is possible to distinguish between the thermal (chemical) and the electrochemical part of the microstructure degradation. Humidity is an important factor that affects the microstructure in the long term. Tortuosity, porosity, and specific resistance change with time, depending on the humidity of the fuel. Tortuosity changes by one order of magnitude in the direction perpendicular to the electrode surface, while in the other two directions in the plane, the changes are only moderate. Porosity increases in all electrochemically treated samples by 1–5% depending on dry ore humidity conditions and time. As all other experimental parameters are the same in all experiments, the EIS results confirm through the increasing specific resistance, mainly the influence of the changes on the microstructure on the electrochemical properties of the cells.

Experimental investigation of a heat pump tumble dryer with a zeotropic refrigerant mixture

Due to their high global warming potential (GWP), fluorinated refrigerants are being replaced in many heat pump and refrigeration systems. Especially in small systems such as heat pump tumble dryers (HPTD), the replacement of the globally used working fluid in this application, R134a, appears to be manageable. One established alternative is the use of hydrocarbon refrigerants. Within this research project, new zeotropic refrigerant blends of hydrocarbons are theoretically evaluated as retrofit substitutes for R134a in heat pump tumble dryers. The aim is to use the temperature glide inherent to zeotropic mixtures during phase change to increase the heat transfer efficiency and thus, the COP of the system. A mixture of R290 (propane) and RE170 (dimethyl ether) was selected and experimentally investigated in a commercially available HPTD. To assess the new mixture, parameters relevant to the cycle such as pressure, temperature, compressor power, and the dryer moisture extraction rate are compared to those values achieved using the refrigerant R134a. Retaining the heat exchanger and compressor from the R134a system, the system charge with the new mixture was 40 % lower, while the thermal capacity was equal to or higher than that of the R134a system. The increased temperature level supplied by the mixture reduced the drying time and the energy consumption of the HPTD. The investigation showed that the heat exchanger design needed to be adapted to the temperature glide properties of the mixture in order to realize meaningful heat transfer efficiency gains.