399 research outputs found

    Although the utility of open stack systems has been widely debated, little empirical research relevant to the controversy is available. Using circula- tion, book availability, and search and library-use statistics, major elements of the direct access debate are tested in a six-year study of a library that has recently undergone the transition from closed to open stacks. Direct shelf access, it was found, contributed to an increase in library use and a decrease in c~rculation. Contrary to expectations, book availability perfor- mance also improved significantly during the study period.

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    Citation analysis was used as an aid in collection development in the field of engineering. It was found that for graduate students books are of greater importance than journals. Substantial reductions in the number o f subscrip- tions released funds for the purchase of books within the limitations of a constant dollar budget. Library usefulness appears to have been increased

    Exploratory and Confirmatory Factor Analysis Indicators of Scale of the Trends of E-learning of University of Technology and Applied Sciences Students\u27

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    The study aimed to identify the indicators of the exploratory and confirmatory factor analysis of a scale of trends Colleges of University of Technology Applied Sciences student\u27s towards E-learning. It also attempts to identify the model which is interpreting of the scale factors, and its psychometric properties. To achieve the objectives of the study, the researcher developed a scale, composed of (22) statements, the scale was used with a sample of (1,203); 365 male and 838 females. The results of the study concluded by identifying two factors that scale statements were load with, The eigenvalue of the first factor was (7.9), and interpret a percentage of variance of (37,8%), while the eigenvalue of the of the second factor was (1.5), and interpret a percentage of variance of (21.4%). Eleven statements were loaded on the first factor which called learning and teaching , The values of statements load were ranged between (0.81 - 0.54), while five statements were loaded on the second factor which called skills and support , and the values of their load were ranged between (0.82 - 0.53). The study found there was statistical significance to the indicator values which proved the model quality and its propertie

    Microstrip antenna with DGS based on CSRR array for WiMAX applications

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    This paper reports a novel method for designing a miniaturized microstrip antenna with DGS based on CSRR array which operates in the frequency of 2.6GHz for low band WiMAX application. The proposed antenna is designed using ANSYS HFSS simulation software. The antenna with optimized parameters is fabricated using FR-4 substrate of thickness 1.6 mm. The simulated and measured performances of the antenna in terms of return loss, directivity and radiation patterns are presented in this work. When Complimentary Split Ring Resonators (CSRRs) array are placed on the ground plane, the resonant frequency is shifted  to a lower value and patch size is reduced .The measurements were taken and compared with the simulated results. The performance characteristics obtained from the measurements show that the proposed antenna is suited for WiMAX application at 2.6GHz

    CPW fed SRR loaded monopole antenna for triple band operations

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    A planar CPW fed SRR loaded monopole antenna based on split ring resonator with triple-band operations is reported for passive UHF RFID, Wireless Local Area Networks (WLAN) and World Interoperability for Microwave Access (WiMAX) applications. Measured and simulated results show the effect of tapering of the SRR layer on bandwidth improvement and gain enhancement in comparison to monopole with SRR antenna. The CPW fed SRR loaded monopole antenna has a bidirectional pattern with high gain for wireless communication applications

    The Optical Qualities of a Solution Made of Copper-doped Silver Sulfide Colloidal Nanoparticles

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    The researchers present new optical properties of Cu-doped Ag2S colloidal solution synthesized via a wet chemical method. They investigate the effects of doping on nanoparticle properties. TEM images reveal spherical samples with sizes ranging from 6 to 18 nm. Doped samples exhibit a redshift in absorption spectra compared to pure Ag2S. Additionally, Pl intensity decreases with increasing Cu concentration. Size estimation from absorption spectra aligns with TEM results, with slight variations. This study unveils the unique optical characteristics of Cu-doped Ag2S colloidal solution, shedding light on the impact of doping and providing valuable insights into nanoparticle behavior and synthesis techniques. Keywords: Metal (Cu); Doped- Ag2S; Optica; PhotoluminescenceDOI: 10.7176/CPER/65-04Publication date: November 30th 202

    Ultra-wideband bandpass filter with notch band based on quadratic Koch Island structure

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    An ultra-wideband bandpass filter with a notch band centered at 7.2 GHz is proposed to remove the interference caused by satellite communication signal coexciting within the ultra wide band. The filter comprises of two seperated quadratic koch island structures connected to the main transmission line to generate the notch band at the desired frequency. The designed ultra wide bandpass filter passes frequencies from 3.09 GHz to 10.61 GHz with a notch band from 7.12 to 7.46 GHz centered at 7.2 GHz and with a rejection level of 21.3 dB.The resonant frequency and bandwidth of the notch can be varied by the variation in the physical parameter of the filter. The proposed filter is fabricated, tested and compared with simulated results

    World Digital Library: An Analysis of Collection

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    Introduction: The World Digital Library, one of the hallmark digital preservation initiatives with a global perspective was launched by the UNESCO and the U.S. Library of Congress in collaboration with 32 partner institutions on April 21, 2009. The World Digital Library archives and provides access to unique cultural materials from libraries, archives, museums, educational institutions, and international organizations from 193 countries around the world. It aims at promoting international and intercultural understanding, expand the volume and variety of cultural content on the Internet, provide resources for educators, scholars, and general audiences, and to narrow the information divide within and among countries by capacity building in partner institutions. Objectives: The World Digital Library provides unprecedented, free of charge access to significant primary historic materials including; manuscripts, maps, rare books, films, sound recordings, prints and photographs. The aim of the present study is to analyze such resources on the basis of the regional attributes, lingual patterns, time periods, subject coverage and institutional contribution. Methodology: The World Digital Library website is being explored to retrieve the information to examine its collection on various facets. Results: The maximum number of resources in the World Digital Library is available on Europe (7276), dealing with History and Geography (16,135), contributed by the Library of Congress (8537) and available in the Arabic language (2830). Implications: The study can act as an indicator highlighting the importance of the WDL as a promising platform for preservation, access and descent of global cultural and heritage resources

    Microstrip multi-stopband filter based on tree fractal slotted resonator

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    This paper presents the design and development of a new microstrip multi-stopband filter based on tree fractal slotted resonator. A single square patch with tree fractal slots of different iterations are employed for realizing dual stopband and tri-stopband filters. The tree fractal slotted resonators are generated from conventional square patch using an iterative tree fractal generator method. First, second and third level iterations of the tree fractal slot resonator are used to design dual and tri-stopband filters respectively. The first level iteration introduced for the tree fractal slot realizes dual bands at 2.64 GHz and 3.61 GHz while the second level iteration provides better stopband rejection and insertion loss at 2.57 GHz and 3.56 GHz. The tri-stopband filter generates three resonance frequencies at 1.53 GHz, 2.53 GHz and 3.54 GHz at third level iteration. By varying the slot length and width of the tree fractal slot, the resonant frequencies can be adjusted and stopbands of the proposed filter can be tuned for the desired unwanted frequency to be rejected. The proposed narrowband filters finds application in removing the interference of GPS and Wi-Max narrowband signals from the allotted bands of other wireless communication system

    Microstrip dual mode multi-bandpass filters based on tree fractal slotted resonator for wireless communication

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    Dual mode microstrip multi-bandpass filter is proposed with tree fractal slot on a square patch resonator. The tree fractal slotted resonators are generated from conventional square patch using an iterative tree fractal generator method. A single square patch is used for realizing both dual and tri-bandpass filters exploiting the dominant, higher order and its corresponding degenerate resonant modes by the tree fractal iteration on the diagonal unequal slots on the square patch.The resonant peaks, transmission zeros and bandwidth of the pass bands can be tuned by varying the length and width of the fractal slot. By optimizing various parameters dual mode dual and tri-band pass filters are simulated, fabricated and measured. The proposed filter finds application in wireless communication devices and falls in the bands of GSM, WLAN, Bluetooth, Zigbee, WiMax and WiFi
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