323,790 research outputs found
An Approach to Eliminate Ambiguity of Blind ML Detection for Orthogonal Space-Time Block Codes
No full textVan-Su Pham, Minh-Tuan Le, Mai Linh, S. M. Humayun Kabir, Giwan Yoo
Silica nano-particulate coating having self-cleaning and antireflective properties for PV modules
No full textIn this research, silica nanoparticles are coated over the solar PV module glass to acquire super hydrophilic, antireflective and highly transparent surface. Silane precursor mixed with air sprayed on the substrate by aerosol deposition method. Pressure difference between the plasma chamber and the substrate is tuned by the introduction of helium gas, which results in good control over layer thickness and refractive indices. Due to the porous nature and graded index of coated film, the transmittance of glass substrate is increased from 91% to 99.2%. Surface topology of coated film is studied by AFM shows excellent antifogging and super-hydrophilic nature attributed to roughness and nano-porosity of coated film. Moreover, the super-hydrophilic nature endows these coatings with self-cleaning properties, which further enhances the overall efficiency of solar PV modules
Synthesis and characterization of novel polycyclic structures, precursors to high performance polymers Humayun Mandal.
No full textOur primary goal in this thesis was to develop convenient methods for the synthesis of oligomeric polycyclics which could be ring-opened at elevated temperatures in the presence of a catalyst to give new classes of thermoset materials.A simple and commercially attractive approach was utilized to synthesize novolac type resins by reacting p-substituted phenols with formaldehyde using a cation exchange resin as catalyst in the presence of chlorobenzene as solvent.Novel oligomeric polycyclic carbonates were prepared by reacting the multifunctional phenol-formaldehyde resin with excess triphosgene under high dilution conditions. When the oligomeric polycyclic carbonates were heated at elevated temperatures using an initiator, a highly cross-linked network was obtained. In addition, the polycyclics were mixed with a commercial BPA polycarbonate and cured at different temperatures in the presence of a catalyst. When the mixture of BPA polycarbonate with 10 wt.% polycyclic carbonate was cured at 350ºC for 30 min. using a catalytic amount of lithium stearate, it gave a highly cross-linked network.Two series of polycyclic phosphonates were synthesized by reacting the oligomeric phenol-formaldehyde resins with phosphonic dichlorides under high dilution conditions in a polar aprotic solvent. The polycyclic phosphonates were similarly subjected to ring-opening polymerization at elevated temperatures in the presence of an initiator. The crosslinked phosphonates exhibited good flame retardance properties.Two classes of oligomeric siloxane resins were also synthesized by reacting the phenol-formaldehyde novolac type resins with dialkyl or diaryl dichloro, silanes under high dilution conditions. The formation of predominantly polycyclic siloxane structures was revealed by MALDI-TOF MS, Gradient HPLC and 1H NMR. Blends of commercial polysiloxane gums with different proportions of polycyclic siloxane resins were subjected to curing at 300ºC in the presence of KOH catalyst. Polysiloxane gums are highly unstable at 300ºC in the presence of a basic catalyst. However, the cross-linked polysiloxane gum at 30 wt.% loading of polycyclic siloxanes, was sufficiently stable at this temperature.A Bisphenol A dimer (o, o' methylene bridged) was synthesized by a single-pot reaction between formaldehyde and excess BPA using cation exchange resin catalyst. A few novel classes of oligomeric polycyclics with low melt viscosities were synthesized from this dimer under high dilution conditions.A series of co-polycarbonates of BPA were synthesized by the reaction of methylene bridged dimer with BPA and triphosgene. An alternative in-situ polymerization method was also developed to synthesize the BPA co-polycarbonates. These co-polymers containing cross-linkable cyclic carbonate moieties on the backbone, gave thermoset materials when cured at elevated temperatures in the presence of a catalyst.Low molecular weight poly(aryl ether sulfone)s end-capped with metallophthalocyanine moieties were prepared by reacting poly(aryl ether sulfone)s containing o-phthalonitrile end-groups with excess phthalonitrile and metals/metal salts in quinoline. These polymers were characterized in detail by using IR, UV-VIS, 1 H NMR and GPC techniques. Annealing studies on the polymers containing PcM end-groups were undertaken in order to investigate the occurrence of stacking of plithalocyanine rings in the melt. This study was conducted by using a Thermo-Gravimettic/Differential Thermal Analysis (TG/DTA) instrument
A Comparative Analysis of Mental Health in Humayun Ahmed's Nondito Noroke and Debi
No full textHumayun Ahmed is a prominent author from Bangladesh, widely read for his ability to blend surrealism within the boundaries of middle-class families in Asian households. Nondito Noroke (In Blissful Hell), was the first-ever work of the author published in the 1970s. The plot revolves around a lower-middle-class family struggling to make ends meet. Rabia, the twenty-two-year-old, female character is the eldest daughter of the family. She suffers from an unexplained mental disability that restrains her duties and allows her to lead a carefree life. Her carelessness ultimately pushes her to death while her family suffers from a deep personal loss that claims three lives. On the other hand, Debi (Goddess) portrays the psychic powers of Ranu, the seventeen-year-old protagonist suffering from Hysteria Schizophrenia. Her extraordinary sensory perceptions of hearing a voice without an external stimulus raise her to the position of a medium for “Debi” to communicate with the human world. This paper attempts to conduct a comparative analysis between Rabia and Ranu through the lens of feminist psychoanalysis and trauma theory, where the former is an oppressed and rejected individual who is constantly pulled apart by the expectation of the conventional society on the norms of gender roles. At the same time, the latter is idolised as a Goddess for her ability to foretell the future. The significance of this research lies in understanding the pattern of mental health in the context of women's development from a South-Asian perspective
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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No full textCan archives of audiovisual TV interviews be used to make authors more visible to students, and thereby reduce the learning gap between native and non-native language speakers in college classes? We examined students in a college course who learned about one scholar's ideas through watching an audiovisual TV interview (i.e., visible author format) and about another scholar's ideas through reading a formal text description (i.e., invisible author format). For the invisible author, native language speakers scored significantly higher than the non-native language speakers on a corresponding exam question (i.e., a cognitive measure), generated more words on the exam question (i.e., a motivational measure), and mentioned the author's name more often in answering the exam question (i.e., an affective measure). For the visible author, the groups did not differ on any of these measures. These findings provide evidence for the idea that making the author visible through audiovisual TV interviews can eliminate the learning gap between native and non-native language speakers. 3 Universities around the world serve students who are non-native speakers of th
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