1,204 research outputs found

    Green Corrosion Inhibitors, Past, Present, and Future

    Get PDF
    Green corrosion inhibitors are of interest because there has been an increase in environmental awareness and a change in regulations that restrict regular corrosion inhibitors due to their toxicity. Natural products are a good source of green corrosion inhibitors, where most of their extracts containing the necessary elements such as O, C, N, and S, which are active in organic compounds, assist in adsorption of these compounds on metals or alloys to form a film that protects the surface and hinders corrosion. Numerous natural products and their application in different processes, especially in steel reinforcement embedded in concrete, are discussed. Development of green chemistry and green chemical technologies offers novel synthetic methods for ionic liquids, which are considered as new corrosion green inhibitors, and their mechanism of adsorption, how these green inhibitors act in different media, and their protective role for different metals and alloys are discussed. Finally, industrial applications of vapor-phase inhibitors and their mechanisms are presented

    On differences between fractional and integer order differential equations for dynamical games

    Full text link
    We argue that fractional order (FO) differential equations are more suitable to model complex adaptive systems (CAS). Hence they are applied in replicator equations for non-cooperative game. Rock-Scissors-Paper game is discussed. It is known that its integer order model does not have a stable equilibrium. Its fractional order model is shown to have a locally asymptotically stable internal solution. A FO asymmetric game is shown to have a locally asymptotically stable internal solution. This is not the case for its integer order counterpart.Comment: 4 page

    On Hermite-Hermite matrix polynomials

    Get PDF
    summary:In this paper the definition of Hermite-Hermite matrix polynomials is introduced starting from the Hermite matrix polynomials. An explicit representation, a matrix recurrence relation for the Hermite-Hermite matrix polynomials are given and differential equations satisfied by them is presented. A new expansion of the matrix exponential for a wide class of matrices in terms of Hermite-Hermite matrix polynomials is proposed

    Prediction of Length of Postoperative Ventilation in CDH Survivors; Preoperative and Operative Variables

    Get PDF
    Background/Purpose: The period taken for complete weaning from ventilation in cases of repaired congenital diaphragmatic hernia (CDH) varies greatly. We tried to relate the endo-tracheal tube removal time (ETTRT) in these cases with the different variables; both preoperative and operative. Materials & Methods: This is a retrospective study of cases of CDH survivors managed by the authors over the period from January 2003 till February 2010. The preoperative variables included gestational age, gender, birth weight, Apgar score, the time of intubation, the ventilation strategy, the presence of a significant PDA in the ECHO study and the time-lapse till surgery. The operative variables (all by laparotomy approach) included the side of the hernia, the herniated contents, the presence of a sac, the insertion of a chest tube and the degree of abdominal wall stretch required. The successful weaning from ventilation and ETTRT were classified into two groups; ≤7 days and > 7 days postoperatively. Results: During the study period, 26 cases were included (21 Males and 5 females). The ETTRT ranged from 2 to 23 days (mean=7.7 ±7.15). Among the variables studied; the statistically significant ones (P value < 0.05) were Apgar score at 1 minute (preoperatively) and the need for "vigorous" abdominal wall stretch (operatively). Conclusion: Apgar score of less than 8 at 1 minute; preoperatively, and the need for "vigorous" abdominal wall stretch; operatively, were associated with delayed weaning from ventilation in CDH survivors. This could have a predictive value in the management of these cases.Index Word: Congenital diaphragmatic hernia, Mechanical ventilation weaning, Endo-tracheal tube removal

    Optimization of EDM process parameters for Al-SiC reinforced metal matrix composite

    Full text link
    Volume 8 Issue 2 (February 201

    Inhibitive Effect of Urea and Urea Derivatives on the Corrosion of Silver in Acetic Acid Solutions

    Get PDF
    The corrosion of silver in acetic acid was studied using potentiodynamic polarization technique in absence and presence of different concentrations of urea, thiourea and N-allylthiourea. The inhibition efficiency was found to depend on both the inhibitor type and concentration. The inhibitive action of these compounds is based on the formation of salt complex and/or the adsorption of the protonated species on the metal surface according to Temkin's isotherm. The thermodynamic parameters Kads and ΔG°ads for the adsorption process are calculated and discussed

    Enhancing radial distribution system performance by optimal placement of DSTATCOM

    Get PDF
    In this paper, A novel modified optimization method was used to find the optimal location and size for placing distribution Static Compensator in the radial distribution test feeder in order to improve its performance by minimizing the total power losses of the test feeder, enhancing the voltage profile and reducing the costs. The modified grey wolf optimization algorithm is used for the first time to solve this kind of optimization problem. An objective function was developed to study the radial distribution system included total power loss of the system and costs due to power loss in system. The proposed method is applied to two different test distribution feeders (33 bus and 69 bus test systems) using different Dstatcom sizes and the acquired results were analyzed and compared to other recent optimization methods applied to the same test feeders to ensure the effectiveness of the used method and its superiority over other recent optimization mehods. The major findings from obtained results that the applied technique found the most minimized total power loss in system ,the best improved voltage profile and most reduction in costs due power loss compared to other methods

    An extremely low-noise heralded single-photon source: a breakthrough for quantum technologies

    Full text link
    Low noise single-photon sources are a critical element for quantum technologies. We present a heralded single-photon source with an extremely low level of residual background photons, by implementing low-jitter detectors and electronics and a fast custom-made pulse generator controlling an optical shutter (a LiNbO3 waveguide optical switch) on the output of the source. This source has a second-order autocorrelation g^{(2)}(0)=0.005(7), and an "Output Noise Factor" (defined as the ratio of the number of noise photons to total photons at the source output channel) of 0.25(1)%. These are the best performance characteristics reported to date

    Nile perch fish nuggets: Partial replacement of fish flesh with sesame hulls and sunroot — Quality assessment and storage stability

    Get PDF
    This study aimed to produce Nile perch fish nuggets by replacing a part of fish flesh with different concentrations of sesame hulls and sunroot to reach the optimal recipe. Chemical, microbiological, and sensory characteristics of nuggets were evaluated during 3 months of frozen storage at –18 °C. According to the obtained data on the chemical composition of raw materials, Nile perch flesh had the highest content of protein (20.21%), sesame hulls contained the highest amount of fat (13.54%), fiber (17.24%) and ash (16.11%), while sunroot tubers had the highest amount of carbohydrates (15.76%). Based on the sensory score, the acceptable replacement ratio for fish nuggets prepared with sunroot (T1) and sesame hulls (T2) was 10% and 7.5%, respectively. Thiobarbituric acid (TBA) analysis at zero time shows that the T1 samples had the minimum value compared to the T2 and control samples. During storage, the TBA levels increased slightly in all samples, but after three months T1 also showed the lowest value. The total plate count (TPC) and psychrophilic bacterial (PSY) count in the samples were affected by the period of frozen storage at –18 °C. The initial TPC and PSY loads were 2.32 and 2.02 log cfu/g for control; 2.24 and 1.72 log cfu/g for T1; 2.30 and 1.47 log cfu/g for T2, respectively. During storage, the values of TPC and Psy slightly decreased. In conclusion, this study succeeded in the replacement of Nile perch fish with sesame hulls and sunroot as new sources to improve the nutritional value and quality characteristics of fish nuggets.This study aimed to produce Nile perch fish nuggets by replacing a part of fish flesh with different concentrations of sesame hulls and sunroot to reach the optimal recipe. Chemical, microbiological, and sensory characteristics of nuggets were evaluated during 3 months of frozen storage at –18 °C. According to the obtained data on the chemical composition of raw materials, Nile perch flesh had the highest content of protein (20.21%), sesame hulls contained the highest amount of fat (13.54%), fiber (17.24%) and ash (16.11%), while sunroot tubers had the highest amount of carbohydrates (15.76%). Based on the sensory score, the acceptable replacement ratio for fish nuggets prepared with sunroot (T1) and sesame hulls (T2) was 10% and 7.5%, respectively. Thiobarbituric acid (TBA) analysis at zero time shows that the T1 samples had the minimum value compared to the T2 and control samples. During storage, the TBA levels increased slightly in all samples, but after three months T1 also showed the lowest value. The total plate count (TPC) and psychrophilic bacterial (PSY) count in the samples were affected by the period of frozen storage at –18 °C. The initial TPC and PSY loads were 2.32 and 2.02 log cfu/g for control; 2.24 and 1.72 log cfu/g for T1; 2.30 and 1.47 log cfu/g for T2, respectively. During storage, the values of TPC and Psy slightly decreased. In conclusion, this study succeeded in the replacement of Nile perch fish with sesame hulls and sunroot as new sources to improve the nutritional value and quality characteristics of fish nuggets
    corecore