Effect of seawater ageing on fracture toughness of stitched glass fiber/epoxy laminates for marine applications

Composite materials are used in various industries such as marine, aircraft, automotive, etc. In marine applications, composites are exposed to seawater, which can affect their mechanical properties due to moisture absorption. This work focuses on the durability of composite materials under the short-term effect of seawater ageing. The specimens were prepared from glass fiber/epoxy using a hand lap-up method and stitched in the z-direction with Kevlar fiber. The specimens were submerged in seawater for 24 and 35 days. A significant decrease in maximum load was found as specimen immersion time in seawater increased. The seawater ageing also affected fracture toughness with a reduction of 30% for 24 days immersion and 55% for 35 days. The ageing also caused the swelling of composites due to moisture absorption, which increased the weight of the specimens. Compared to the dry specimens, the weight of the specimen for 24 days increases to 5.2% and 7.89% for 35 days’ seawater ageing. The analysis also showed that due to seawater ageing, the de-bonding rate increased as the number of days increased

A new ceramide along with eight known compounds from the roots of Artemisia incisa pamp

A new compound (1) (named as artemceramide-B) together with eight known compounds (taraxerol (2), taraxerol acetate (3), β-sitosterol (4), stigmasterol (5), trans-ethyl caffeate, dracunculin (7), scoparone (8) and isoscopoletin (9) were isolated from an ethanolic extract of the roots of Artemisia incisa Pamp (Asteracae). The structures of the compounds were determined through IR, 1D NMR (1H NMR, 13C NMR) and 2D NMR (COSY, NOESY, HSQC and HMBC) analyses. Accurate mass analyses were done with EI-MS, ESI-MS and acid methanolysis of compound 1 followed by GS-MS studies. The relative stereochemistry of artemceramide-B was determined by comparing its specific rotation and spectroscopic data with the literature. Compounds 1-9 were tested for their anti-bacterial potential against five bacteria strains; Staphylococcus epidermidis, Staphylococcus aureus, Klebsiella pneumoniae, Bacillus subtilis and Escherichia coli. Compound 1 (new) (MIC: 0.0157, 0.0313 mg/mL) and 7 (MIC: 0.0815 , 1.000 mg/mL) showed excellent activities against S. epidermidis and S. aureus while compound 9 showed excellent activities (MIC: 0.0700 , 1.234, 1.890 and 2.286 mg/mL) against S. epidermidis,S. aureus, K. pneumoniae and E. coli, respectively. Compound 6 (MIC: 2.000 mg/mL) was found to be active against E. coli while neither of the compounds showed potential activity against B. subtilis

On Subclasses of Analytic Functions with respect to Symmetrical Points

In our present investigation, motivated from Noor work, we define the class ℛks(b) of functions of bounded radius rotation of complex order b with respect to symmetrical points and learn some of its basic properties. We also apply this concept to define the class Hks(α,b,δ). We study some interesting results, including arc length, coefficient difference, and univalence sufficient condition for this class

Chemistry of enzymatic browning in longan fruit as a function of pericarp pH and dehydration and its prevention by essential oil, an alternative approach to SO2 fumigation

Background Longan fruit is a rich source of bioactive compounds; however, enzymatic browning of pericarp and microbial decay have limited its postharvest life. SO2 has widely been used to overcome these limitations; however, due to safety and regulatory concerns, alternative means should be identified. In this study, antioxidant and antimicrobial properties of thymol (TH) essential oil were investigated against the enzymatic browning and decay of longan fruit. Methods Fruits were coated with TH (4%) for 5 min, sealed in polyethylene (PE) packages and stored at 4 °C for 42 d. Fruits immersed in distilled water (DW) and stored in PE were used as control. Results TH extended the postharvest life of longan to 42 d than 28 d in DW. TH residues decreased from 142 to 11.17 mg kg–1, while no residues were found at day 42. TH significantly (P ≤ 0.05) reduced the respiration rate, inhibited polyphenol oxidase (PPO) and peroxidase (POD) enzyme activities, sustained high phenols/flavonoids and prevented pericarp browning (BI) than DW. TH also effectively (P ≤ 0.05) maintained the color values, firmness of peel and aril, total soluble solids (TSS), titratable acidity (TA), inhibited decay incidence (DI) and resulted in lower ethanol content than DW. BI as a function of pericarp pH was highly correlated; pH and BI (r = 0. 97), with PPO (r = 0.93) and with water loss (r = 0.99). A high coefficient of correlation of BI was found with the pericarp pH, enzymes, phenolic, water loss and decay incidence with ethanol. TH could be the best alternative to SO2 and other synthetic preservatives

Compositional analysis of natural pomegranate peel powder dried by different methods and nutritional and sensory evaluation of cookies fortified with pomegranate peel powder

IntroductionFortification of cereal products with natural plant extract is an interesting approach to fulfill the dietary requirement of the people.Materials and methodsPeels of pomegranate (rich source of natural compounds) were cut into small pieces and dried in three different methods such as solar drying (SOD), oven drying (OD), and sun drying (SUD). The fine powder was prepared and proximate compositions (protein, ash, moisture, fats, fiber, and carbohydrates), minerals (zinc, iron, calcium, and potassium), total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity (DPPH) of the pomegranate peel powder (PP) were evaluated. Fine wheat flour (FWF) was fortified with different concentrations (3, 6, 8, 10, and 12 g) of PP powder, cookies were prepared and all the above analysis along with physical parameters (weight, width, thickness, spread ration) and sensory analysis were conducted. Cookies without PP powder were served as control.Results and discussionResults showed that a SOD was the best for drying PP powder in terms of compositional analysis. Addition of PP powder significantly (P < 0.05) enhanced the nutritional value, minerals profile and physical attributes of the fortified cookies. Sensory analysis of fortified cookies indicated that the cookies were acceptable to the sensory panel. Therefore, in conclusion, PP powder dried by SOD method could be used commercially in baking industries to provide nutritional enriched cookies to fulfill the dietary requirements of the people

NN-QuPiD Attack: Neural Network-Based Privacy Quantification Model for Private Information Retrieval Protocols

Web search engines usually keep users’ profiles for multiple purposes, such as result ranking and relevancy, market research, and targeted advertisements. However, user web search history may contain sensitive and private information about the user, such as health condition, personal interests, and affiliations that may infringe users’ privacy since a user’s identity may be exposed and misused by third parties. Numerous techniques are available to address privacy infringement, including Private Information Retrieval (PIR) protocols that use peer nodes to preserve privacy. Previously, we have proved that PIR protocols are vulnerable to the QuPiD Attack. In this research, we proposed NN-QuPiD Attack, an improved version of QuPiD Attack that uses an Artificial Neural Network (RNN) based model to associate queries with their original users. The results show that the NN-QuPiD Attack gave 0.512 Recall with the Precision of 0.923, whereas simple QuPiD Attack gave 0.49 Recall with the Precision of 0.934 with the same data

An Integrated Approach of Hypobaric Pressures and Potassium Permanganate to Maintain Quality and Biochemical Changes in Tomato Fruits

Limited postharvest life of tomato fruit is due to its highly perishable nature. Hypobaric pressure is a new emerging hurdle technology usually used up to a pressure of 100 kPa for the preservation of fruits and vegetables. In this study, an integrated approach of hypobaric pressures (40 kPa and 50 kPa) and sponge-dipping of potassium permanganate (KMnO4) was designed for the postharvest life extension of tomato fruits. Fruits were treated with either 400 ppm of KMnO4, or 40 or 50 kPa hypobaric pressures, or their combination. Fruits without any treatment was considered as a control treatment. All groups were packaged in polypropylene trays as ready to retail and stored at room temperature at 25 ± 1 °C for 21 days. Basic quality parameters such as pH, total soluble solid, percent weight loss, percent spoilage, firmness, ethylene production rate, and color were evaluated at 3-day intervals. Results showed the application of hypobaric pressures and KMnO4, either alone or in combination, provided a synergistic effect in maintaining the quality compared to the control treatment during the 21 days of storage. The highest decay was found in the control compared to the combined treatments of KMnO4 + 40 kPa and KMnO4 + 50 kPa. Similarly, a decrease in firmness and color values was highest in the control treatment followed by the KMnO4 and 50 kPa hypobaric pressure compared to the combined treatment of KMnO4 + 50 kPa. In the same way, a high ethylene production rate was observed in the control, while the lowest ethylene production rate was found in KMnO4 + 50 kpa. Sensory evaluation indicated a highest score of 9 on the 9-point hedonic scale of tomato fruits. Among all groups, the combined application of 50 kPa hypobaric pressure + 400 ppm KMnO4 retained the best overall quality attributes compared to all other treatments throughout the experiment; therefore, this treatment could be applied at a commercial level for tomato fruits

Antimicrobial properties of extracts and compounds isolated from Berberis jaeschkeana

The present study was undertaken to evaluate the anti microbial properties of Berberis jaeschkeana Schneid Var. jaeschkeana for the first time. The screening of B. jaeschkeana for its phytochemical constituents showed the presence of alkaloids, glycosides, flavonoids, steroids, saponins reducing sugars and terpenoids. Crude ethanolic extract and different fractions showed good antimicrobial properties. Five compounds isolated for the first time from this plant also showed good antimicrobial properties. Columbamine was found to have excellent antimicrobial properties among all the compounds

QuPiD Attack: Machine Learning-Based Privacy Quantification Mechanism for PIR Protocols in Health-Related Web Search

With the advancement in ICT, web search engines have become a preferred source to find health-related information published over the Internet. Google alone receives more than one billion health-related queries on a daily basis. However, in order to provide the results most relevant to the user, WSEs maintain the users’ profiles. These profiles may contain private and sensitive information such as the user’s health condition, disease status, and others. Health-related queries contain privacy-sensitive information that may infringe user’s privacy, as the identity of a user is exposed and may be misused by the WSE and third parties. This raises serious concerns since the identity of a user is exposed and may be misused by third parties. One well-known solution to preserve privacy involves issuing the queries via peer-to-peer private information retrieval protocol, such as useless user profile (UUP), thereby hiding the user’s identity from the WSE. This paper investigates the level of protection offered by UUP. For this purpose, we present QuPiD (query profile distance) attack: a machine learning-based attack that evaluates the effectiveness of UUP in privacy protection. QuPiD attack determines the distance between the user’s profile (web search history) and upcoming query using our proposed novel feature vector. The experiments were conducted using ten classification algorithms belonging to the tree-based, rule-based, lazy learner, metaheuristic, and Bayesian families for the sake of comparison. Furthermore, two subsets of an America Online dataset (noisy and clean datasets) were used for experimentation. The results show that the proposed QuPiD attack associates more than 70% queries to the correct user with a precision of over 72% for the clean dataset, while for the noisy dataset, the proposed QuPiD attack associates more than 40% queries to the correct user with 70% precision

QuPiD Attack: Machine Learning-Based Privacy Quantification Mechanism for PIR Protocols in Health-Related Web Search

With the advancement in ICT, web search engines have become a preferred source to find health-related information published over the Internet. Google alone receives more than one billion health-related queries on a daily basis. However, in order to provide the results most relevant to the user, WSEs maintain the users’ profiles. These profiles may contain private and sensitive information such as the user’s health condition, disease status, and others. Health-related queries contain privacy-sensitive information that may infringe user’s privacy, as the identity of a user is exposed and may be misused by the WSE and third parties. This raises serious concerns since the identity of a user is exposed and may be misused by third parties. One well-known solution to preserve privacy involves issuing the queries via peer-to-peer private information retrieval protocol, such as useless user profile (UUP), thereby hiding the user’s identity from the WSE. This paper investigates the level of protection offered by UUP. For this purpose, we present QuPiD (query profile distance) attack: a machine learning-based attack that evaluates the effectiveness of UUP in privacy protection. QuPiD attack determines the distance between the user’s profile (web search history) and upcoming query using our proposed novel feature vector. The experiments were conducted using ten classification algorithms belonging to the tree-based, rule-based, lazy learner, metaheuristic, and Bayesian families for the sake of comparison. Furthermore, two subsets of an America Online dataset (noisy and clean datasets) were used for experimentation. The results show that the proposed QuPiD attack associates more than 70% queries to the correct user with a precision of over 72% for the clean dataset, while for the noisy dataset, the proposed QuPiD attack associates more than 40% queries to the correct user with 70% precision