85 research outputs found
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
Humayun Kabir, Men and Rivers, and Faridpur
No full textIn the history of South Asian literature in English, Men and Rivers is the third fictional work written by a Muslim author after Rokeya's Sultana's Dream and Ahmed Ali's Twilight in Delhi (1940). Men and Rivers is a literary work of great merit though more research needs to be conducted on the work to appreciate its value by examining various thematic and stylistic features. Through Men and Rivers, Hamayun Kabir conferred on Faridpur literary immortality. I believe the novel will continue to make the district memorable and special to its readers for a very long time
Perspectives on the assessment of audit risk for “Bokhteyar Humayun & Co.” in Bangladesh
No full textThe internship report was prepared on the topic of “Perspectives on the assessment of audit risk for Bokhteyar Humayun & Co. in Bangladesh”. Audit is the procedure of verifying financial statements of a particular organization that whether they have prepared their statements according to applicable laws & regulations and presented reasonably true information. It is a process that was used since the ancient age of accounting. It is very significant to secure honesty and integrity in the financial sector of any country. Audit has basically three classifications: External, internal and government audit. Auditors have to face some risks and challenges during their audit procedure, these are called audit risks. There are three main categories of audit risks: Inherent risk, Control risk and Detection risk. Based on the risk assessment, auditors give four types of opinions: Unqualified, qualified, adverse and disclaimer. As the author has worked in “Bokhteyar Humayun & Co.” as an intern, he has found that his firm actually faces those three types of risks which are mentioned above. The author has also critically analyzed risk assessment and he has also found some key issues and recommended some solutions for his firm. The author has tried to work as a sincere member of his organization and demonstrated a high level of professionalism during his internship period which has been certified in his “Internship Completion Certificate” in the appendix part
Royal Assemblies and Imperial Libraries: Polygonal Pavilions and Their Functions in Mughal and Safavid Architecture
No full textThis article examines the architectural form and potential functions of two royal buildings: the Sher Mandal and the Guldasta pavilion. An octagonal tower located in the Purana Qila in Delhi, the Sher Mandal was in all likelihood the library (kitab-khana) built by the Mughal emperor Humayun (r. 1530-56). Erected during the reign of the Safavid ruler Shah Abbas I (r. 1587-1629), the now-vanished Guldasta pavilion was located south of the palace complex in Isfahan and can be studied through drawings and photographs. A close examination of the formal structure of the two buildings reveals that they belong to a distinct type of polygonal pavilion that first emerged in the late fifteenth century in the works of architecture sponsored by the Timurid dynasty (c. 1370-1405). Moreover, this comparative study opens up new venues for investigating the physical setting of the royal kitab-khana in Mughal and Safavid contexts
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
Dielectric and infrared studies of radio frequency processes in some alcohols
No full textIn this thesis, the results of dielectric studies on a number of aliphatic
alcohol molecules with variable chain lengths are presented. This investigation was
complemented by infrared and viscosity measurements. Dielectric studies were
confined to the radio frequency range using an H.P. 419lA RF Inpedance Analyzer.
The experimental data, as a function of frequency and temperature, were subjected to
analysis by a series of computer programs written in APL language. The activation
energy barriers for the dielectric relaxation were obtained by application of the
Eyring rate equation.
Initially, a number of pure liquid alcohol molecules were studied with
increasing chain length in a wide temperature and frequency range. The effect of
size on the relaxation parameters could then be revealed. In all cases a Debye type
process was observed which is in accordance with the literature report
A few of these alcohols were also studied in a variety of solvents ranging
from inert to strongly interacting. The experimental relaxation times were compared
with the theoretical ones obtained using Higasi's theory of the dielectric relaxation
mechanism. Furthermore, the relaxation parameters were analysed in terms of
solute-solute and solute-solvent interactions.
The importance of chain length on the associative equilibria was examined.
Methanol, which has no chain length and no intramolecular motion within the
experimental temperature and frequency ranges, was selected for this purpose. A
detailed dielectric study for this alcohol was carried out in different media.
An attempt was made to gain insight into the impact of steric hindrance on
the relaxation times and energy parameters. Small alcohols were substituted by larger alcohol molecules in three component systems. The position of the dipole
was varied for different alcohols in two component systems. These studies
constitute the latter part of this thesis
برصغیر میں بابر و ہمایوں کاعہد حکومت (1526۔1540): ایک تجزیاتی مطالعہ
No full textBabar is prominent among all the Mughal kings because he is the founder of the Mughal Empire in the subcontinent. He was a man of many high qualities. He was author of a book; his Tazak Babri is a wonderful book. It is not rhetoric, but a description of what has been observed. In addition to Tuzak Babri, he invented the Babri script and wrote several copies of the Qur'an in this style and sent them to Mecca. A study of the Babri period shows that he promoted the principle of tolerance and religious He did not kill anyone on the basis of differences. He behaved sympathetically despite winning wars. Humayun was knowledgeable and gentle. He was known for his cheerfulness, gentleness and social interaction. Although Humayun was a brave man but he could not control the army like Babar. In the same way, his brothers quarreled with him and put obstacles in his way. All these reasons led to his failure against Sher Shah Suri. Humayun had a special interest in morphology and mathematics. He himself was a poet and He was also an appreciator of poets. This article is an analytical study of the Babar and Humayun eras
M.A.L.D.I.-T.O.F. mass spectrometry characterization of 4-alkyl substituted phenol-formaldehyde novalac type resins
No full text
بیگم صغریٰ ہمایوں: حیات، ادبی اور سماجی خدمات
No full textBegum Sughra Humayun was a recognized author, poetess, and social active member of women rights protection movement. She took written as well as practical steps for reinforcement of women dignity and education. She also earned popularity in the field of writing travelogue. This research paper presents her biographical sketch as well as an overview of her literacy and social contributions
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