Synthesis and Morphology of High Density Barium Zirconate Ceramics

Barium Zirconate (BaZr03) is an inert target material with high resistance to temperature and chemical reaction, which can be used as a crucible. In some literatures, BaZr03 with small particle size is also proposed as material for multilayer capacitors. In this research high dense BaZr03 has been synthesized through a common method, solidstate reaction, where large amount of fine BaZr03 powder can be obtained and further sintered at high temperature to gain high density material. In this study, nitrate precursors were used to lower the formation temperature of BaZr03. The raw materials (Ba(N03)Z and ZrO(N03)z.HzO in 1:1 molar ratio) were calcined at 800De for 8h to obtain a fine and pure BaZr03 crystal. The calcine powder was analysed with X-ray diffraction to confirm that there were no unwanted impurities. The calcined powder was also analysed with laser particle-size analyser and scanning electron microscope to gain more information on the particle sizes and morphology. The low temperature of calcination produced fine powder « lm). Fine powders always facilitate fast boundary diffusion during sintering. Sintering the green pellet between 12000C and 17000C showed vast information of morphology changes. BaZr03 with 0.6!J,m was obtained at 12000C with dwell time of 24h. Further sintering at 16000C for 6h produced a high dense pellet with no or near zero porosity and about 90% density compared to theoretical value. The crystallite size is ranged between 0.36!J,ffi to 0.44!J,ffi. However, the pellets had shrink of about 13%. To prevent the large shrinkage, sintering aids were used. Magnesium oxide (MgO), yttrium oxide (Y203), Aluminium oxide (Ah03), and Barium Stannum oxide (BaSn03) were added up to 5% separately with the calcined BaZr03 powder and sintered between 15000C and 1700oC. Interestingly, with the presence ofMgO, Y203 and Ab03 the sintering shrinkage was reduced to only 2%. Even though there was some level of porosity, BaZr03 with MgO and Y203 pellets with shown about 90% densification

Prevalence of Human T-Cell Lymphotropic Virus Type 1 and Chemosensitivity of Leukaemia and Lymphoma Cells in Adult Patients in Malaysia

The elucidation of virus-cancer associations is of particular importance since large numbers of people are potentially exposed to cancer. The first link relates to the causation of adult T-cell leukaemia/lymphoma (ATL), a highly malignant haematological malignancy of mature activated T cells with a poor prognosis, by a retrovirus called human T-cell lymphotropic virus type-1 (HTLV-1). The HTLV-1 tax oncoprotein plays an integral role in productive viral replication and disease progression. Seroprevalence studies demonstrated that the distribution of HTLV-1 is heterogeneous worldwide and not specific to a particular region only. Patients with this disease have a very poor prognosis because of intrinsic chemoresistance and severe immunosuppression. Hence, the general objective of the present study is to establish the prevalence of HTLV infections in leukaemia and lymphoma adult patients. The experimental design consists of two folds: screening for the presence of HTLV-1 tax gene and chemosensitivity profiles of patient cells treated with clinical chemotherapeutic agents. A total of 140 subjects consisted of lymphoid leukaemia (12%), myeloid leukaemia (26%) and lymphoma patients (62%) were included in this study. First line screening was performed using ELISA and PCR was used to detect HTLV-1 tax gene followed by confirmation using direct DNA sequencing. Mononuclear cells were isolated using density gradient centrifugation from bone marrow or peripheral blood samples of adult patients admitted to Universiti Malaya Medical Centre (UMMC), Ward 6TD. Patient cells were treated based on standard chemotherapeutic regimen for 96 hours and assessed using 3-(4, 5- dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) cytotoxicity assay. Initial ELISA screening showed 9 samples were initially reactive and 7 patients were classified indeterminate due to inconsistency of immunoassay replicates. Further confirmation by PCR validated all seropositive patients and only four of the indeterminate samples, which yields a prevalence of 9.29% in 140 adult patients. Concurrently, the HTLV-1 tax positive patient’s chemosensitivity profiles were compared with the seronegative samples. However, a distinct relationship between the presence of HTLV-1 tax gene and chemosensitivity between these groups were not obtained. This preliminary study provided a baseline data on the prevalence of HTLV-1 infections in leukaemia and lymphoma adult patients. However, the lack of direct association of HTLV-1 tax gene with the chemotherapy resistance was mainly due to the limited sample size used in this study. Further studies should be performed in a larger cohort of patients and healthy subjects to further substantiate the preliminary data

Cooperative control of dual arm manipulator

This research focuses on the development of a controller for the cooperation control of dual arm mechanical manipulator. A controller for the position control of unconstrained robot arm without velocity measurements is also presented; The experimental set-up consists Remotec\u27s RM-10A dual arm manipulator. Each arm has six separate motorized motions with position sensors. The arm has also an end effector and is provided with a six axes Force/Torque sensor. The manipulator is controlled by two TMS320C40 parallel Digital Signal Processors. The control software which is embedded on the Digital Signal Processor is developed using C language. A Graphical User Interface is also developed using Microsoft Visual C++ to facilitate easy operation of the robot; A PID controller is implemented for the position control of the manipulator. Experiments are performed both in joint space and in Cartesian space and the results are presented

Level sets of condition spectrum

For $0\u3c\epsilon\leq 1$ and an element $a$ of a complex Banach algebra $\mathcal{A}$ with unit $e$, the level set of $\epsilon$- condition spectrum is defined as $$L_{\epsilon}(a)\coloneqq\left\{\lambda\in \mathbb{C} : \|(a-\lambda.e)\|\left\|(a-\lambda.e)^{-1}\right\|=\frac{1}{\epsilon}\right\}.$$ We prove the following topological properties about $L_{\epsilon}(a)$ \begin{enumerate} \item If $\epsilon=1$ then $L_{1}(a)$ has an empty interior unless $a$ is a scalar multiple of the unit. %$L_{1}(a)$ has non empty interior for $a = \lambda$ where $\lambda\in \mathbb{C}$ and \item If $0\u3c\epsilon\u3c1$ then $L_{\epsilon}(a)$ has an empty interior %for $a = \lambda$ where $\lambda\in \mathbb{C}$ and also for any $a$ which is not a scalar multiple of the unit, $L_{\epsilon}(a)$ has empty interior in the unbounded component of the resolvent set of $a$. Further, we show that, if the Banach space $X$ is complex uniformly convex or $X^{*}$ is complex uniformly convex, then for any operator $T\in B(X)$, $L_{\epsilon}(T)$ has an empty interior. \end{enumerate

The Cost of Freedom: Revolutionary Hopes & Realities Among Young Tunisians A Decade Post-Arab Spring

The Arab Spring of 2011 was an incredible tale of desperation, defiance, and vast political transformations—of civil society across North Africa and the Middle East revolting against dictatorship, corruption, and demanding democracy and freedom. Tunisia gained widespread international attention following the revolutions as the sole country to attain democracy. However, many Western scholars and news reports have dismissed Tunisia’s triumph as a lucky break and lauded its attainment of democracy and, especially, its newfound freedom of expression. Such a focus on “Tunisian exceptionalism,” however, ignores the nuanced consequences that have accompanied the country’s vast political transformation. Situated a decade post-Arab Spring in Tunisia, this research explores the impact of the Revolution and democracy on one particular facet of society: freedom. The concept of freedom is a complex, charged, and fluid one. This paper seeks to unpack it through three main strands: its acquisition, performance and manifestation, and costs, through the lived experiences of young Tunisian artists. This was the demographic central to catalyzing, and subsequently, benefitting from what is considered the Revolution’s sole gain: freedom of expression. This study is a primarily ethnographic one that consists of interviews and case studies from one performance arts space in urban Tunis. In discussing freedom and its nuanced expressions through lived realities, this study finds that there is much left to be desired in civil society today and implores a critical analysis of the framing structures of Western neoliberal democracy and postcolonialism that haunt the country

The Short-term Effect of Playing Co-operative and Competitive Card-/Board Games on Pro-social Behavior

The thesis experiment tested whether card-/board games could be used to increase pro-social behavior among participants. Positive results would give credence to their use for improving team work among groups, e.g. in the work place. The study utilized three different games, a cooperative, a neutral and a competitive game. Participants were randomly assigned a game to play for 5 minutes before being given a pro-social task. The pro-social task involved asking participants to assign tangram puzzles of varying difficulty for another person to solve, and if the person could solve 10/11 puzzles within a 10 minute time frame they would receive a monetary reward. The participants could, thus, help the other person by assigning easy puzzles or hinder them by assigning difficult puzzles. The study found differences in pro-social tendencies among the three game groups however the differences were not statistically significant. The effect of gender was also analyzed, and no statistically significant difference was found between genders. The result was unexpected as past research testing video games effect on pro-social behavior found significant differences between violent, co-operative games and neutral games. Three potential reasons for the result were identified. First the utilized game time of 5 minutes was very short, pro-social scripts may not have had enough time to be primed in the participants’ minds and thus their effect on the pro-social task were negligible. The medium of card-/board games may not have been beneficial in inducing the pro-social behavior. Finally it is worth noting that while not statistically significant there was an increase in pro-social tendencies both in the competitive and co-operative game group. Both games were played with other participants, while the neutral game was played solo. This may suggest that the context of playing with other people mattered more than the content of the game played. The study found that short durations of game play utilizing card-/board games did not show statistically significant benefits in improving pro-social behaviors

The ICT Induced Business Reconfiguration from Evolution to Revolution (A Case Study of Public Sector Banks in Sri Lanka)

This paper explores the recent revolutionary levels ofBusiness Reconfiguration in the Public Sector Banks in SriLanka through a Case Study exploratory analysis. This study hascompared the five levels of Business Reconfiguration introducedby Venkatraman (1991) with the Sri Lankan Public SectorBanks. Findings show that rather than evolutionary levels, thesebanks have achieved the revolutionary levels of businessReconfiguration within a short period of time and it is believedthat they will achieve the optimum capability of level five in nearfuture

Implementation of MPICH on top of MPLi̲te

The goal of this thesis is to develop a new Channel Interface device for the MPICH implementation of the MPI (Message Passing Interface) standard using MPLi̲te. MPLi̲te is a lightweight message-passing library that is not a full MPI implementation, but offers high performance. MPICH (Message Passing Interface CHameleon) is a full implementation of the MPI standard that has the p4 library as the underlying communication device for TCP/IP networks. By integrating MPLi̲te as a Channel Interface device in MPICH, a parallel programmer can utilize the full MPI implementation of MPICH as well as the high bandwidth offered by MPLi̲te. There are several layers in the MPICH library where one can tie a new device. The Channel Interface is the lowest layer that requires very few functions to add a new device. By attaching MPLi̲te to MPICH at the lowest level, the Channel Interface, almost all of the performance of the MPLi̲te library can be delivered to the applications using MPICH. MPLi̲te can be implemented either as a blocking or a non-blocking Channel Interface device. The performance was measured on two separate test clusters, the PC and the Alpha mini-clusters, having Gigabit Ethernet connections. The PC cluster has two 1.8 GHz Pentium 4 PCs and the Alpha cluster has two 500 MHz Compaq DS20 workstations. Different network interface cards like Netgear, TrendNet and SysKonnect Gigabit Ethernet cards were used for the measurements. Both the blocking and non-blocking MPICH-MPLi̲te Channel Interface devices perform close to raw TCP, whereas a performance loss of 25-30% is seen in the MPICH-p4 Channel Interface device for larger messages. The superior performance offered by the MPICH-MPLi̲te device compared to the MPICH-p4 device can be easily seen on the SysKonnect cards using jumbo frames. The throughput curve also improves considerably by increasing the Eager/Rendezvous threshold

Two mode coupling in a single ion oscillator via parametric resonance

Atomic ions, confined in radio-frequency Paul ion traps, are a promising candidate to host a future quantum information processor. In this letter, we demonstrate a method to couple two motional modes of a single trapped ion, where the coupling mechanism is based on applying electric fields rather than coupling the ion's motion to a light field. This reduces the design constraints on the experimental apparatus considerably. As an application of this mechanism, we cool a motional mode close to its ground state without accessing it optically. As a next step, we apply this technique to measure the mode's heating rate, a crucial parameter determining the trap quality. In principle, this method can be used to realize a two-mode quantum parametric amplifier.Comment: 8 pages, 5 figure

Steady pressure measurements in the strap-on booster interference Region of 1/20 scale aslv configuration

Wind tunnel studies were carried out to obtain pressure distribution in the strap-on booster interference region of 1/20th scale Augmented Satellite Launch Vehicle model configuration. Tests were done in the 1 .2m tunnel at NAL in the Mach number range of 0 .5 to 2.5 for the clean configuration as well as with spring housing attachments on the strap-on boosters. Both the model configurations with the boosters strapped on to the core vehicle in the horizontal plane (pitch) and in the vertical plane (yaw) were tested for incidences at 0, 4 and -4 deg. In addition pressure measurements were also done on the core vehicle alone at Mach numbers 2.1, 2.5 and 3.0 for 0, +4 degree incidences. The test Reynolds number was varied from 0.7 to 1.3 millions based on the maximum diameter of the model. The pressure distribution showed significant interference effects of boosters on the core vehicle. It is observed that the positive pressure peak associated with flow compression at the flare junction increases with increase in Mach number. In the pitch plane the normal force distribution remains positive along the core vehicle whereas in the yaw plane it is of less magnitude