Duration Of Immersion Research Articles

Evaluation of Mono-Diacyl Glycerol (MDAG) purification process to increase product yield

Monodiacyl glycerol (MDAG) was successfully synthesized by esterification of palm fatty acid distillate (PFAD) and glycerol with acid catalyst. MDAG products with mono and diacyl glycerol content > 90% were obtained after purification through solvent extraction and crystallization at low temperature. However, the yield of purified MDAG products was only around 16.23% so it was not economically feasible. The aim of this study was to evaluate effect of the hydrolysis process before the esterification process and got the best conditions of solvent extraction in the MDAG purification, to improve yields of purified MDAG. The hydrolysis process was done on PFAD (or PFAD activation) to break down the remaining triglyceride and maximize the presence of free fatty acid that can react with glycerol. Evaluation of solvent extraction process included determination of crude MDAG and hexane ratio (1:10, 1:8, 1:4), determination of ethanol to water volume ratio (1:0, 1:0.5, 1:1, 0.5:1) with various immersion duration (24, 48, 72 h). The data analysis was done with a description method and completely randomized design method (CRD) with a significance level of 5% (P <0.05 %). The activation of PFAD was carried out by reacting PFAD with water at ratio of 1:6 (w/v). This process used para-toluene sulfonic acid (pTSA) as a catalyst, which added as much as 1.2% of the weight of PFAD. The hydrolysis process was done for one hour at 110 °C. From esterification using pre-treated PFAD obtained crude MDAG with FFA content of 4.69%, yield of purified MDAG of 24.7% with no FFA was detected. The best MDAG to hexane ratio was 1:10 which has a yield of purified MDAG of 19.30% and 0% FFA content. While the best ethanol to water volume ratio was 1:0.5 with immersion time for 24 h, where the yield of purified MDAG was 27.78%.

Effects of process parameters on the microstructure of iron coating fabricated on pure aluminum by immersion plating

AbstractIn this paper, an iron coating was designed to fabricate on the surface layer of pure aluminum. The effects of process parameters such as immersion plating method, durations and temperatures on the microstructure of iron coating were studied systematically. The experimental results showed that the quality of the iron coating fabricated on the sample by one‐step immersion plating is better than that obtained by two‐step immersion plating. The iron coating obtained by one‐step immersion plating for 1 min is continuous and without obvious gaps and cavities. With the immersion time increased to 3 min and 5 min, the coating is uneven and easy to fall off from the surface of sample. Additionally, due to that the higher temperature increases the efficiency of displacement reaction, the quality of the coating obtained at 40 °C is better than that obtained at 55 °C and 65 °C. Consequently, the optimal immersion plating parameters were one‐step immersion plating, 1 min, and 40 °C. This paper provides a novel method to prepare an iron coating as a pretreatment for electroplating of aluminum.

The Effectiveness of Musa Paradisiaca as Green Inhibitor for Mild steel in Marine Corrosion

Corrosion is characterized as metal and alloy degradation or destruction due to a chemical or electrochemical response to the surrounding environment or medium. Different metals corrode at different rates. Many organic and inorganic compounds have been investigated in the control of corrosion by adding the corrosive fluids as they are readily accessible, inexpensive, sustainable and environmental friendly. This research evaluates the effectiveness of Musa paradisiacal as an organic inhibitor of mild steel in marine corrosion. The gravimetric and linear polarization methods were applied to study the corrosion behaviour of mild steel. All the parameters analysed showed good inhibitory characteristics against the corrosion of mild steel in solution being tested, and their efficiency was found to increase with the inhibitor concentration. After a varied immersion duration, the gravimetric and electrochemical measurements for mild steel in seawater showed that the presence of Musa paradisiacal significantly reduces the corrosion densities (icorr) of 0.44 X 10−6 Acm−2 and corrosion rates of 0.00507 mm/year, as the polarization resistance (Rp) of 2536.6 and inhibition efficiency (IE) of 99.38 % are synchronously increased.

Aloe-Gel Coating for Delaying Physicochemical Change of Fresh-Cut Mango

Fresh-cut arumanis mango is current popular product, stimulated by lifestyle and community needs for quality fruit with little preparation. Stripping and cutting spur the damage of fresh-cut mangoes faster than whole mangoes. Aloe vera gel coating as an alternative to maintain the characteristics of fresh-cut mangoes and extend shelf life. This study aims to delaying the physicochemical change of fresh-cut mango with aloe vera edible coating. The design used is a completely randomized design (CDR) of two factors, namely the ratio of dilution of aloe vera gel with aquadest 1:0, 1:1 and 1:2. Factor II, duration of immersion 1, 2 and 3 minutes with observations on the 5th and 10th days stored at cold temperatures (7± 1) °C. Observation variables include physical properties, namely weight loss, color and texture. Whereas observations of chemical properties, namely pH, total solubvle solid, water content and vitamin C. The best results were obtained in a combination of 1:1 aloe vera gel with 3 minutes immersion with a weight loss value of 1.40%, color b (∆E) 63.12, texture 6.82N, pH 4.65, TSS 24.60°Brix, moisture content 83.51% and vitamin C 35.60mg/100g).

A test method to evaluate the fuel oil corrosion resistance of asphalt binders

The oil immersion binder bond strength (BBS) test, a test method based on the well-established BBS test, was designed and performed. This method evaluates the fuel oil corrosion resistance performance of asphalt binders indirectly according to the loss of pull-off tensile strength (POTS) due to fuel oil corrosion, defined as ΔPOTSO values. First the effects of loading rate and asphalt film thickness on the oil immersion BBS test results were studied. Oil immersion BBS tests under various conditions were then applied in order to study the changes in POTS and ΔPOTSO values with oil immersion duration and oil temperature. Suitable experimental conditions were determined in these two steps. Finally, oil immersion BBS test findings were analyzed in comparison with those of other performance tests. Results indicate the selection of 0.7 MPa/s and 0.2 mm as the appropriate loading rate and asphalt film thickness, respectively. Various oil immersion durations and oil temperatures had different impacts on the POTS and ΔPOTSO values of different asphalt binders, with ΔPOTSO values indicating the cohesive strength loss of asphalt binders due to oil immersion. Increases in the ΔPOTSO values of these asphalt binders gradually lessened with increasing oil immersion duration. Furthermore, the ΔPOTSO values of most asphalt binders were related to their solubility in diesel oil, according to asphalt fuel oil corrosion tests. ΔPOTSO values obtained under the conditions of 40 °C for 2 h were positively correlated with results of asphalt mixture performance tests, thus determining the appropriate oil temperature and oil immersion duration for the oil immersion BBS test. Under appropriate conditions, the oil immersion BBS test has the advantages of simple operation, high accuracy, and good discrimination.

The Effect of Pure Garlic (Allium Sativum L.) Juice on The Color Stability of Heat Polymerized Acrylic Resin Denture Base

Intoduction : PMMA or acrylic resin is a necessary material in dentistry for denture bases, one of which is often used is heat cured acrylic resin or heat polymerized acrylic resin. Garlic juice is a denture cleaner to inhibit bacteria and is also an extrinsic factor that causes discoloration. Purpose: To determine the duration of immersion in pure garlic juice which can cause discoloration of the acrylic resin. Methods: laboratory experiments with posttest only control group design research. Results: The mean ± SD change in color of hot polymerized acrylic resin after immersing in garlic juice for 2, 4, 6, 8 hours was 0.67 ± 0.22; 0.91 ± 0.31; 1.22 ± 0.32; and 1.56 ± 0.25. Conclusion: There is an effect of soaking time with garlic juice on the base of denture acrylic resin on discoloration.

Study on anti-corrosion of PVA-treated wheat straw and its application in reinforcement of a silty soil

Silty soils are usually with poor mechanical performance and thus need reinforcement to meet the requirements in geotechnical practices. Wheat straw is low-cost, environment-friendly and wide spread, which has a great potential for use as reinforcement of the silty soils. In this study, the anti-corrosion effect of polyvinyl alcohol (PVA) treated wheat straw was investigated through the pore area ratio tests and the tensile tests. Test results indicated that the wheat straw was greatly improved in anti-corrosion, and tensile strength was considerably enhanced after the treatment. The optimum concentration of PVA solution and immersion duration were suggested. The PVA-treated wheat straw was then buried in the silty soil, and its corrosion resistance to the environment in the soil was validated under different moisture conditions. The treated wheat straw was then used as the reinforcing material for improvement of a silty soil. Triaxial compression were carried out on the samples reinforced with the material of various inclusion contents and lengths. Stress–strain curves and strength of the reinforced soil samples were analyzed, and the optimum inclusion content and length were discussed. The California bearing ratio (CBR) tests were then performed for the reinforced soil with the optimum inclusion content and length, and the test results showed that the reinforced silty soils met the requirements on CBR of the subgrade.

Evaluation of physical and dynamic mechanical properties of coconut husk ash (CHA) reinforced polyester composites

The evaluation of physical and dynamic mechanical analysis (DMA) properties was carried out using developed CHA Reinforced Polymer Composite. Sieve analysis of pretreated CHA was done to obtain 75 µm, 150 µm and 300 µm particles sizes. These particles were used at varying compositions of 5%, 10%, 15%, 20% and 25% as reinforcements for polyester composites. The catalyst and accelerator used were Methyl Ethyl Ketone Peroxide and Cobalt Naphthenate respectively. The densities of the evaluated composites made with 150 μm particles were found to be less dense with values ranging from 0.9792 g/cm3 to 1.2561 g/cm3 than those made with 75μm and 300μm. The results also show that the percentage water absorbed by samples increased, ranging from 0 to over 2000 E’/MPa for all percentage reinforcements of CHA, with an increase in the duration of immersion of the samples in distilled water. However, 25% reinforcement had better results for all particle sizes. There were obvious variations of storage modulus, loss modulus and mechanical loss factor with percentage weight of reinforcement, temperature and frequency. The composite with 15 % reinforcement displayed better results and can be used as a material for interior components in aerospace and automobile industries.

An engineering-oriented approach to construct rough micro/nano-structures for anticorrosion and antifouling application

Slippery liquid-infused porous surfaces (SLIPS) have attracted considerable attention because of their multiple beneficial applications. In this report, styrene-butadiene-styrene triblock copolymer (SBS) and SBS-SiO2 films with 3D interconnected net-like structures were constructed via a simple solution blow spinning method. The original films exhibited excellent hydrophobicity with a contact angle of 145°, after infiltration with the lubricant, the contact angle of SLIPS was reduced to 110°. The antifouling and anticorrosion performance of the hydrophobic surfaces and SLIPS were also studied. The hydrophobic surfaces showed inferior antifouling and anticorrosion performance because of the large pores in the films, significantly, the lubricant-infused surface demonstrated dramatically improved antifouling and anticorrosion performance. More interestingly, compared with a silicone oil-infused surface, the perfluoropolyether oil-infused surface displayed durable anticorrosion properties over increased immersion durations. The failure mechanism of lubricants was explored. The combined anticorrosion and antifouling capability of the constructed microstructure has excellent potential application in marine environments.

Ultrasonically Assisted Macrocyclic Ring Compound Coatings for Corrosion Protection of Copper in 3.5% NaCl Solution

Macrocyclic ring compounds are potential corrosion inhibitors due to their high planarity, rigidity, and presence of many heteroatoms such as nitrogen, oxygen, phosphorus, and sulfur. However, their application as corrosion inhibitors has been faced with the challenge of insolubility in most organic and aqueous solvents. To overcome this challenge and to harness the untapped hydrophobic property of these compounds, this research, via ultrasonication method, dispersed a macrocyclic ring compound known as free-based phthalocyanine (Pc) to fabricate a corrosion-resistant coating on the Cu surface. The Cu samples were coated through a 24 h immersion by self-assembly method in different systems of sonicated and nonsonicated solutions of the compound in dimethyl sulfoxide (DMSO). The effect of sonication and immersion duration on the coating morphology, compactness, and consequent corrosion inhibition was analyzed. Electrochemical and surface imaging techniques revealed higher corrosion protection in 3.5% NaCl for the Pc-coated Cu samples after sonication compared to the nonsonicated systems.

Color Stability and Surface Properties of PMMA/ZrO2 Nanocomposite Denture Base Material after Using Denture Cleanser

Objectives This study aimed to evaluate denture cleanser effects on color stability, surface roughness, and hardness of PMMA denture base resin reinforced with nano-ZrO2. Materials and Methods A total of 420 specimens were fabricated of unreinforced and nano-ZrO2 reinforced acrylic resin at 2.5% and 5%, resulting in 3 main groups. These groups were further subdivided (n = 10) according to immersion solution (distilled water, Corega, sodium hypochlorite, and Renew) and immersion duration. Surface roughness, hardness, and color were measured at baseline (2 days-T0) in distilled water and then after 180 and 365 days of immersion (T1 & T2) in water or denture cleansing solutions. Data was collected and analyzed using two-way ANOVA followed by Bonferroni post hoc test (α = 0.05). Results Surface roughness increased significantly after denture cleanser immersion of unmodified and nano-ZrO2-modified PMMA materials while hardness decreased (P < 0.001). The denture cleansers significantly affected the color of both PMMA denture bases (P < 0.001). The immersion time in denture cleansers significantly affected all tested properties (P < 0.001). Within denture cleansers, NaOCl showed the highest adverse effects (P < 0.05) while Renew showed the least adverse effects. Conclusion Denture cleansers can significantly result in color change and alter the surface roughness and hardness of denture base resin even with ZrO2 nanoparticles addition. Therefore, they should be carefully used.

Copper corrosion mitigation: A new insight for fabricating a surface barrier film against chloride ion under hydrodynamic flow

The influence of hydrodynamic flow, nickel tungstate (NiWO4) dosage, immersion duration, self-healing, and synergistic effect of NiWO4 and 5-mercapto-1-phenyl-1H-tetrazole nanocomposite film deposited on Cu surface were studied. The film thickness of ~2 µm showed excellent adhesion to Cu surface as proved by ASTMD 3359 – 97 standard adhesion tape test and extended immersion duration with 96.5% protection efficiency achieved under flow. SEM and electrochemical techniques revealed a more enhancement of Cu protection against pitting corrosion of chloride ion with a self-healing effect observed on a scratched portion of the coating in the presence of the composite compound, unlike the bare Cu surface.

New insights on the porous network created during solvent debinding of powder injection-molded (PIM) parts, and its influence on the thermal debinding efficiency

Mn-Zn ferrite components were successfully produced using Powder Injection Molding (PIM) from a binder system (11.5 wt%) made of paraffin wax (PW), linear low density polyethylene (LLDPE) and stearic acid. Solvent debinding kinetics of the molded parts depended on n-hexane temperature, on immersion duration and on part’s geometry. The volume to surface ratio of the considered parts were comprised between 1.3 and 4.0. The primary binder (PW) removal created a porous network having a narrow average pores distribution centered on a diameter of about 50 nm. We highlighted by using Archimedes’ principle and mercury intrusion porosimetries that the parts achieved a maximal open porosity disregarding their volume to surface ratio, while it was still possible to remove additionnal PW. This maximal porosity (12.6 %) has proved to be the most relevant parameter for the definition of an optimal solvent debinding duration (∼15−20 h at 40 °C). Using this chemical debinding step, it was possible to reduce our thermal debinding duration by 62.5 % (80 h–30 h) while avoiding the occurrence of structural defects as cracking or deformations on the parts. The sintered PIM parts had a density of about 4.84 g/cm3 (94.9 % of relative density) and a magnetic saturation polarization of about 500 mT what is very similar to parts produced using the conventional fabrication techniques. These results should be useful to understand how to improve the production rate of ferrites fabricated by PIM technology.

PENGARUH LAMA PERENDAMAN AIR KELAPA MUDA TERHADAP PERTUMBUHAN STEK BIBIT VANILI (Vanilla planifolia Andrews)

This study was conducted to determine the appropriate duration of immersion in young coconut water on the growth of vanilla seed cuttings. This research was conducted at the Payakumbuh State Agricultural Polytechnic Experimental Garden in March – June 2021. The experiment used a one-factor completely randomized design (CRD) with five replications. The experimental units were five levels of immersion time, 2 hours of immersion (P1), 4 hours of immersion (P2), 6 hours of immersion (P3), 8 hours of immersion (P4), and 10 hours of immersion (P5). Parameters observed were shoot emergence, root emergence, internode growth, shoot diameter, root wet weight, and shoot wet weight. The results showed that the immersion time of young coconut water with 10 hours of immersion (P5) was able to produce better seedling growth compared to other treatments in each parameter of observation.

Application of petai peel as an iron corrosion inhibitor in sodium chloride medium

Tannin as an organic inhibitor has been proven capable as a metal inhibitor in acidic media. The purpose of this study is to test the tannin ability of the Petai peel to inhibit the iron plate in the sodium chloride solution. The inhibitory ability of tannins derived from the Petai peel will be assessed in the form of powders, concentrated extracts, and pure tannins. Corrosion rate and efficiency of inhibition as tested parameters will be calculated by doing some variations on the immersion time and inhibitor concentration. Based on the results obtained, Petai peel powder, Petai peel concentrated extracts, and tannins from Petai peels can reduce the rate of iron corrosion in sodium chloride solution, but the best inhibitors of these three forms are in the form of tannins, which can reach the lowest corrosion rate of 0.9770 mpy and inhibition efficiency up to 92.86%. The lowest corrosion rate and highest efficiency are obtained by adding tannin as much as 3 g and immersion duration for 3 days.

Thermodynamic-based cross-scale model for structural soil with emphasis on bond dissolution

The immersion weakening effect of natural soil has always been a difficult problem encountered in geotechnical engineering practice. The bond dissolution is a common cause of soil strength deterioration, which is not yet fully understood. In this study, a thermodynamic-based constitutive model of structural soils based on the α model is first established, considering the bond strength by modifying the yield surface size and gradually reducing the bond strength with the development of plastic strain. Furthermore, by taking the meso-mechanisms of bond dissolution into account, the evolution rule of the free energy during the bond dissolution process is derived based on a homogenization approach, and a thermodynamic-based constitutive model of structural soil with bond dissolution is thereafter developed. By comparing with the results of one-dimensional compression tests and conventional triaxial tests, the model is verified to be capable of reflecting the gradual destructuration process of soil while loading. The comparison with triaxial test results of completely decomposed granite after different immersion durations and parametric studies show that based on the cross-scale energy equivalence, the model can well reflect the strength deterioration characteristics of completely decomposed granite with bond dissolution mechanisms at the mesoscale fully considered.

Bond durability of epoxy and cement- bonded CFRP reinforcement to concrete interfaces subject to water immersion

Durability is a critical concern for concrete structures externally bonded with fiber-reinforced polymer reinforcement. This paper presents the results from an experimental study which compared the bond durability of epoxy-bonded CFRP sheets and cement-bonded CFRP grids to concrete interfaces subjected to water immersion. Totally twelve groups of CFRP sheet or grid-strengthened concrete beams with a notch at their midspan were carefully fabricated through epoxy- and cement-based bonding systems and tested under monotonic loading before and after water immersion exposure, respectively. The cement binder included polymer cement mortar (PCM) and ductile engineered cementitious composite (ECC). The CFRP grids and sheets were designed with the similar tensile stiffness. The duration of water immersion ranged from 0 to 6 months. The test results indicated that debonding in concrete adjacent to the concrete-adhesive interface in accompany with a diagonal concrete crack near the notch was the main failure mode of the beams strengthened with epoxy-bonded CFRP sheet and ECC-bonded CFRP grid, while the tearing off of CFRP grids from the PCM matrix was the main failure mode of the beams strengthened with PCM-bonded CFRP grids. After water immersion exposure, the ultimate loads of the beams with cement-based CFRP grids were at least 50% higher than their epoxy-bonded counterparts, confirming the superior moisture durability of cement based bond to epoxy-bonded ones. The interfacial fracture energy was found to exhibit an exponential decline trend with water immersion duration.

IDENTIFIKASI KADAR AIR, TINGKAT KECERAHAN DAN CITARASA KOPI ROBUSTA DENGAN VARIASI LAMA PERENDAMAN

Coffee is one type of plantation commodity favored by the community. The coffee beans obtained must have a good moisture content, brightness and taste. Based on the results of analysis of variance (ANOVA), it shows the effect of soaking time on the water content of Robusta coffee beans with treatment KT&gt; Error KT, namely 2.5609&gt; 0.05093. At the brightness level, the longer the soaking process, the lower the brightness value of the Robusta coffee beans without horn skin. The results of analysis of variance (ANOVA) soaking time had an effect on the brightness level of Robusta coffee beans. The analysis test results show that the value of treatment KT &gt; error KT where the value is 23.151 &gt; 2.187. The taste of Robusta coffee for each panelist has a different value, based on the results of the research on the taste of Robusta coffee, panelists prefer coffee with 24 hour immersion. The results of analysis of variance (ANOVA) for the duration of immersion significantly affected the taste of Robusta coffee, where the value of treatment KT &gt; error KT was 10.84742 &gt; 0.192182.

Comparison of Volumetric Dimensional Changes of Calcium Aluminate, Resin Modified Glass Ionomers and Resin Luting Cements Among Different Storage Conditions

Objective: The aim was to evaluate the volumetric dimensional changes of calcium aluminate glass-ionomer luting agent to resin modified-Glass ionomer cement (RM-GIC), self-etch and conventional resin based cement (RBC) among different storage conditions. Methods: Twenty cylindrical specimens (7 mm × 2 mm) for four cements [Calcium aluminate (Ceramir-CM), RM-GIC (Fuji Plus-FP), RBC (Rely X Ultimate-RA) and RBC-self-etch (Rely X Unicem-RU)] were fabricated and polished. Five specimens from each material were randomly assigned to the four test conditions. These conditions were silicone oil at 22 °C and 37 °C and distilled water at 22 °C and 37 °C respectively. A resolution balance was used to measure the weight of each specimen at 1, 2, 3 and 4 weeks. Archimedes’ principle equations were used to measure volumetric dimensional changes. Ion release analysis for Ca+ and OH- of the storage medium solution of calcium aluminate cement was performed using atomic absorption spectroscopy and pH measurement respectively at 1, 2, 3 and 7 weeks. Data was analyzed using ANOVA and Tukey post hoc test. Results: A significant difference in volumetric changes (ρ &lt; 0.05) was observed for different cements. Calcium aluminate (CM) showed maximum volumetric changes followed by FP. However, resin cements (RA and RU) showed significantly lower volumetric changes. Oil immersion exhibited shrinkage and water immersion showed volumetric expansion in all materials. Increase in duration of immersion, increased the dimensional changes (shrinkage or expansion) among all cement groups (ρ &lt; 0.05). Both temperature and duration showed significant influence on Ca+ ion release. Conclusions: Calcium aluminate cement had the highest level of dimensional changes (17.28% and 20.52%) while both resin luting agents show least expansion without a significant difference between them. Ceramir luting agent expands significantly in water and continues to release Ca2+ ions with time and higher temperature. The clinical use of calcium aluminate cements based on the high dimensional changes observed in the study is debatable.

The fat content and the preferences of salted duck egg enriched with black and white pepper

This study was aimed to determine the fat content and the preferences of salted duck egg enriched with black and white pepper. The experimental was designed as completely randomized design with 2 factors. First factor was concentration of black and white pepper (10%, 15% and 20%), while the second factor was length of salting period which are 7 and 10 days. Fat content was determined by Soxhlet extraction method, and the product preferences was determined by using hedonic scale test. The preference test was done at white egg and yolk color, taste of saltiness, aroma and gritty texture. Results showed that, fat content of salted duck egg with pepper addition tend to decrease along with the duration of immersion. According to the preferences test, salted duck egg at 20% black and white pepper were mostly preferred at 10 and 7 days salting period, respectively.