GLORIA

GEOMAR Library Ocean Research Information Access

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (821)
Document type
  • Articles  (821)
Source
Publisher
Years
  • 1
    Publication Date: 2018-03-14
    Description: In this study, the assessment of radon concentration in drinking water in some regions of Baghdad city in Iraq has been studied using CR-39 solid-state nuclear track detector technique. A total of 18 samples selected from 6 region (5 samples from each region) in Baghdad city have been placed in the dosimeters for 50 day. The average radon concentration was found to be \(516.1 \hbox { Bq/m}^{3}\) which is greater than the standard international limit ( \(300 \hbox { Bq/m}^{3}\) ). The potential alpha energy concentration and annual effective dose have been calculated. A proportional relationship between the annual effective dose and radon concentration within the studied region has been certified.
    Print ISSN: 1319-8025
    Electronic ISSN: 2191-4281
    Topics: Natural Sciences in General , Technology
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2018-03-14
    Description: Epoxy resin is known to react with a hardener such as polyamine to form a thermoset 3D polymer net with an outstanding physical and mechanical properties. They are widely used in coating and adhesives. In this study, we present a new epoxy resin material useful for making an anticorrosive formulation for carbon steel. The epoxy resin presented in this study is diglycidyl ether 4, \(4^{\prime }\) -dihydroxy diphenyl sulfone (DGEDDS). It was prepared in a two-step process that involves reacting epichlorohydrin with 4, \(4^{\prime }\) dihydroxy diphenyl sulfone then with sodium hydroxide. The structural elucidation of DGEDDS was carried out with Fourier transform infrared. The anticorrosive formulation DGEDDS–MDA–ZPH was prepared from DGEDDS and the hardener 4, \(4^{\prime }\) -methylene dianiline (MDA) in the presence of the anticorrosion pigment zinc phosphate tetrahydrate (ZPH). Another standard formulation (DGEDDS–MDA) was prepared without ZPH. The physicochemical and anticorrosive performance of the coated carbon steel was evaluated using electrochemical impedance spectroscopy (EIS). The coated surface was subjected to morphological characterization by SEM before and after immersion in the corrosive medium and exposing it to the UV radiation. The value of the polarization resistance ( \(R_{\mathrm{p}}\) ) obtained by the EIS method for the standard coating DGEDDS–MDA and epoxy composite coating DGEDDS–MDA–ZPH was 31898 and 72611 \(\Omega \,\hbox {cm}^{2}\) during the 1 h of immersion in 3 wt% NaCl, respectively. After aging by exposing the coatings for a 2000 h to UV radiation the values were dropped to 2596 and 5189 \(\Omega \,\hbox {cm}^{2}\) , respectively. The values show the high stability and resistance of the epoxy resin coating to electrolytes and UV radiation. The coating even showed higher stability in the presence of ZPH pigment. As shown in the results, the tricomponent composite showed an outstanding stability in protecting carbon steel form corrosion in an aggressive marine environment where UV is very intense and the humidity and salts are very high.
    Print ISSN: 1319-8025
    Electronic ISSN: 2191-4281
    Topics: Natural Sciences in General , Technology
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2018-03-14
    Description: We used the binary collision approximation code Marlowe to simulate displacement cascades in tantalum monocarbide. We investigated the damage production, the spatial configurations of the resulting defects, and the vacancy clustering. Statistics over 5000 cascades were accumulated, and primaries with kinetic energies up to 20 keV were launched from lattice sites. Elastic collisions between atoms were modeled by the universal Ziegler–Biersack–Littmark, Molière, and Born–Mayer potentials. The Lindhard–Scharff–Schiott theory was used to account for the inelastic energy losses. Principal components analysis was utilized to evaluate the volume of the damaged zone. Analysis of the simulation results shows that no more than 40% of the displaced Ta and C atoms constitute permanent damage. The number of surviving tantalum Frenkel pairs is about twice the carbon one. The cascade volume distributions deviate from a Gaussian distribution showing high degree of dispersion. Only small vacancy clusters are observed within the investigated range of the primary energies, and 33% of the produced vacancies are considered as isolated point defects in 20 keV cascade.
    Print ISSN: 1319-8025
    Electronic ISSN: 2191-4281
    Topics: Natural Sciences in General , Technology
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2018-03-14
    Description: Nowadays, a huge amount of data are available and shared in collaborative scenarios. These scenarios exist due to the need for joint computations of cooperating data owners for the purpose of making analysis and knowledge extraction. This requirement comes together with some privacy issues. One major issue is how to enable query execution, while no party is allowed to see the entire dataset (computational privacy). Thus, secure multiparty computation protocols allow a group of distrustful data owners to jointly cooperate in executing analytical queries against their data while revealing nothing about the entire dataset. In this paper, we propose a technique that enables a privacy-preserving query processing on horizontally partitioned electronic medical records among a set of hospitals, which have no desire to share their confidential data; however, they all need to cooperate to answer global queries about patients’ medical history. The proposed technique depends on a bucketization technique to reduce computational costs. It relies on a head party, which acts as a mediator between the authorized users and the cooperating parties, which are arranged in a star exchange topology. It ensures that the head party learns nothing about the sensitive data. Our experimental results prove that our technique provides a smaller computational cost and better privacy without the need for a trusted third party.
    Print ISSN: 1319-8025
    Electronic ISSN: 2191-4281
    Topics: Natural Sciences in General , Technology
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2018-03-12
    Description: The objective of this research was to investigate the effect of cross-linking and oxidation on the structure of guar gum (GG) in heterogeneous phase system and ultimately to achieve the functional improvement of GG. The experimental results indicated that the crystalline structure of GG particles was not an amorphous structure, and the cross-linking occurred unevenly on GG. The surface of oxidized cross-linked guar gum (OCLGG) particles was severely eroded by the oxidant. Cross-linking was different from oxidation in the destruction manner and uniformity. Oxidation of hydrogen peroxide led to the breakage of GG molecular chains and its reduction in viscosity. The cross-linking and oxidization reduced the freeze–thaw stability and swelling power of GG, but increased its viscosity stability and retrogradation. They also obviously changed the thermal stability of GG and moved the peak of DSC curve of both cross-linked guar gum (CLGG) and OCLGG to the right. As a result, the peak temperature and melting enthalpy of GG were altered considerably. The reactive blue-XBR in the simulated waste water could be well removed by OCLGG. The novelty of the work lies in dimethyldichlorosilane being first used for GG cross-linking and a modification combinations such as cross-linking and oxidation with the function of chain scission.
    Print ISSN: 1319-8025
    Electronic ISSN: 2191-4281
    Topics: Natural Sciences in General , Technology
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2018-03-12
    Description: The existing automatic control program and its parameters for three machines in a fully mechanized Coal Mining face are static and simplex and are therefore inadequate for satisfying the complex and dynamic environment of underground coal mines. To overcome this problem, a collaborative mathematical model is established that includes the effects of a dynamic environment. A virtual reality collaborative planning simulator with methods for the three machines is also proposed based on a multi-agent system. According to the dynamic characteristics of the environment, equipment, and technologies, a fully mechanized Unity3D simulator (FMUnitySim) is designed in terms of multiple factors and multiple dimensions. The factors affecting the coordinated operation of the three machines are analyzed and modeled. The communication modes, coordination, and redundant sensing process among multiple agents, which include the shearer agent and the scraper conveyor agent, are also investigated in detail. Using this system, the key parameters of the three machines can be planned and adjusted online to design and distinctly observe the corresponding collaborative simulations of coordinated operation with multiple perspectives and in real time. Tests of different maximum shearer haulage speeds for regular or reverse transporting coal are designed; their key parameters, including the average shearer haulage speed, average follower distance, and average scraper conveyor load, are planned and simulated using FMUnitySim. The optimal parameter combination is obtained by analyzing and comparing the simulation results. The proposed FMUnitySim offers an effective means and theoretical basis for the rapid planning and safe automatic production of a fully mechanized Coal Mining face.
    Print ISSN: 1319-8025
    Electronic ISSN: 2191-4281
    Topics: Natural Sciences in General , Technology
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2018-03-12
    Description: Binary image, typically black and white, has the advantages of simple storage and compact structure. With the application of digital technology, a lot of important information, such as personal records, medical records, certificates, handwritten signatures, design drawings, and collection of books, has been scanned into digital documents and stored as binary images. Besides, cartoons and sketches in art design are often in the form of black-and-white image. Hiding data in these binary images either for side information delivery or as annotation of the content has great application needs. However, because of the particularity of binary image, the algorithm and system of information hiding in binary image are quite different from that in gray image and color image, and information hiding in binary image is far more challenging. Due to these reasons, research work on information hiding in binary image is fewer. In this paper, we construct coding tables for data hiding and extraction based on HVS in suitable blocks of binary images. Under the condition that the content of the image is not obviously changed, the proposed technique achieves higher hiding capacity than the state-of-the-art homogeneous techniques. Since the computational cost of both data hiding and blind extraction is very low, the proposed technique is very suitable for real-time applications as a steganography.
    Print ISSN: 1319-8025
    Electronic ISSN: 2191-4281
    Topics: Natural Sciences in General , Technology
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2018-03-09
    Description: The arid and semi-arid countries often experience floods due to torrential rainfall events. Appropriate strategy to collect and store rainwater and surface runoff can augment water resources in these countries. In Saudi Arabia, a total of 449 dams with capacity of 2017 million \(\text {m}^{3}\) are available to control floods, recharge aquifers and to supply for domestic and agricultural applications. The southwestern region of the country experiences flash floods, indicating the scope of water resources augmentation through runoff collection. In this study, location of a new dam was identified in Abha, Saudi Arabia, using the watershed modeling system (WMS) software. The WMS software and HEC-HMS hydrologic model were used to delineate watershed and to quantify runoff. The fuzzy rule-based modeling approach was applied to incorporate uncertainty. This study demonstrates that the rainfall events of 25-, 50- and 100-year return periods can generate surface runoff of 10.18 (range 1.77–22.24), 13.08 (range 2.91–26.94) and 16.09 (range 4.25–31.62) million \(\text {m}^{3}\) , respectively. Use of runoff from these events can save US$ 0.94–35.4, 1.5–42.8 and 2.3–50.3 million, respectively, which can also reduce \(\text {CO}_{2}\) emission by 24.6–346.9, 40.5–420.3 and 59.1–493.3 million kg, respectively.
    Print ISSN: 1319-8025
    Electronic ISSN: 2191-4281
    Topics: Natural Sciences in General , Technology
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2018-03-09
    Description: The major reasons of the road accidents are the traffic problem and human erroneous driving. The researchers have started developing self-driving cars to avoid such accidents. In this paper, bicycle vehicle model along with its inverse vehicle dynamic model have been developed to track the predefined path and replace the driver. A bicycle vehicle model using bond graph (BG) is created to avoid single and two obstacles of known different geometry in predefined path. The obstacle avoidance algorithm is developed in the Matlab environment and this consists of combination of line following, tangent bug and wall following algorithm. The trajectory data from the obstacle avoidance controller is fed to the inverse controller of bicycle vehicle model to run the forward model of bicycle vehicle. For the trajectory tracking of bicycle vehicle model, the system inversion is carried out through the bond graph-based overwhelming controller. The simulation results for trajectory tracking of bicycle model is presented for single and two static obstacles with different orientations and shapes, and finally, conclusions are presented to show that response of the forward model follows the command (actual path decided by the obstacle avoidance controller) within the acceptable limits. All the results and simulations are obtained using Matlab and \({Symbols Shakti}^\circledR \) software (Bond graph software).
    Print ISSN: 1319-8025
    Electronic ISSN: 2191-4281
    Topics: Natural Sciences in General , Technology
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2017-05-24
    Description: The potential of poly(3-hydroxybutyrate- co -3-hydroxyvalerate) P(3HB- co -3HV) copolymer production has remained unexplored for Cupriavidus sp. USMAA1020. This study is devoted to a full range exploration on the biosynthesis of polyhydroxyalkanoate (PHA) containing 3HV monomer, from the screening of carbon sources to the optimization of fermentation parameters. Fatty acid (oleic acid) and alcohol (1-pentanol) was found to be the best combination which resulted in high cell dry weight (CDW) (9.4 g/L), as well as high PHA accumulation of 76 wt%. Alcohols were found to be less toxic compared to other 3HV precursors; meanwhile, oleic acid contributed to sufficient amount of acetyl-CoAs as the building block for PHA thus contributing to high PHA content. Improvement was strategized by focusing on 1-pentanol concentration, incubation period and temperature which are the major factors affecting the copolymer production. An optimization study has resulted in high CDW (13.3 g/L) and PHA concentration (10.23 g/L), which increased significantly to 45 and 43%, respectively, compared to pre-optimized culture. This study warrants the usage of oleic acid and 1-pentanol as one of the viable strategies for industrial scale production of P(3HB- co -3HV) copolymer.
    Print ISSN: 1319-8025
    Electronic ISSN: 2191-4281
    Topics: Natural Sciences in General , Technology
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...