Development of Asbestos - Free Brake Pad Using Bagasse

Development of asbestos-free brake pad using bagasse was investigated with a view to replace the use of asbestos whose dust is carcinogenic. The bagasse were sieve into sieve grades of 100, 150, 250, 350 and 710µm. the sieve bagasse was used in production of brake pad in ratio of 70%bagasse-30%resin using compression moulding. The properties examined are microstructure analysis, hardness, compressive strength, density, flame resistance, water and oil absorption. The microstructure reveals uniform distribution of resin in the bagasse. The results obtained showed that the finer the sieve size the better the properties. The results obtained in this work were compared with that of commercial brake pad (asbestos based) and optimum formulation laboratory brake pad Palm Kernel Shell based (PKS), the results are in close agreement. Hence bagasse can be used in production of asbestos-free brake pad

A numerical analysis of condenser performance of a seawater desalination system

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Cataloged from PDF version of thesis.Includes bibliographical references (p. 31).This thesis presents the numerical analysis of three type condensers for desalination of seawater system. The condensers that were analyzed were a finned tube condenser that was built in Malaysia desalination plant, a cooling tube condenser in Jordan, and a common plate finned tube condenser. The goal of the analysis is to observe the thermal performance parameters of a condenser such as heat and mass transfer coefficient, surface effectiveness and condensate flow rate. The parameters that were changed in the analysis were the face velocity of air, the water velocity, and the number of rows of tubes. The numerical analysis was done based on basic heat exchanger analysis using e-NTU method for a dry case, and using a j-factor correlation that was developed by McQuiston for studying the wet case. Results from the basic heat exchanger analysis showed the air humidity ratio profile and temperature profile of air and water at the outlet of the condenser. The exit air temperature and humidity ratio were inversely proportional to the length of the condenser, whereas the temperature of the water at the outlet was proportional to the length of the condenser. Results from the j-factor correlation method show that the heat and mass transfer coefficient of the system increased when the number of rows of tubes, face velocity and water velocity increased. Similarly, the analysis showed that the condensate flow rate was highly influenced by the face velocity. In addition, the surface effectiveness was inversely proportional to the face velocity.by Hassan Mohamed.S.B

Blood Biochemical Profile and Carcass Characteristics of Weaner Rabbits Fed Varying Inclusion Levels of Gamba Grass (Andropogon gayanus Kunth.) Forage

A study was conducted to investigate the effect of varying inclusion levels of Gamba grass (Andropogon gayanus Kunth) forage on haematological, blood biochemical and carcass characteristics of weaner rabbits. A total of 20 male rabbits of mixed breeds with an average initial weight of 450g were randomly assigned into four dietary treatments containing varying inclusion levels of gamba grass forage (0, 5, 10 and 15%). There were four rabbits per treatment, each serving as a replicate in a completely randomized design. Blood samples were collected at the end of eight (8) week feeding period before the carcass analysis.. Results indicated that there were significant (P<0.05) increasing trend in the haematological and blood biochemical parameters measured. There were 51% and 55% increases (P<0.05) in total protein (8.53 vs. 5.65g/dl) and calcium ions (2.65 vs. 1.18mmol/dl) in rabbits fed diet containing 15% inclusion level of gamba grass forage compared to the control. However, there were 10% and 17% decreases (P<0.05) in white blood cells (4.92 vs. 4.43%) and alkaline phosphate (89.33 vs. 76.33IU/dl) in rabbits fed the control diet than those fed diet containing 15% inclusion level of gamba grass. Also, there were 13% and 49% increase (P<0.05) in dressing percentage (54.80 vs. 48.60%) and weight of thigh (16.95 vs. 11.35%) in rabbits fed diet containing 15% inclusion level of gamba grass forage compared to the control. However, length of small intestine and weights of heart, head, stomach and small intestines were similar (P>0.05) across the treatments, respectively. It was concluded that gamba grass forage can be included up to 15% in the diet of weaner rabbits, without adverse effect on haematological, biochemical profile and carcass characteristics of the rabbits in Northern Guinea savanna of Nigeria. Gamba grass (Andropogon gayanus Kunth) forage can be included in the diets of weaner rabbits to reduce cost of production.Keywords: Blood, competition, carcass, feed, gamba, Nigeria, rabbi

The Shape of Gravity in a Warped Deformed Conifold

We study the spectrum of the gravitational modes in Minkowski spacetime due to a 6-dimensional warped deformed conifold, i.e., a warped throat, in superstring theory. After identifying the zero mode as the usual 4D graviton, we present the KK spectrum as well as other excitation modes. Gluing the throat to the bulk (a realistic scenario), we see that the graviton has a rather uniform probability distribution everywhere while a KK mode is peaked in the throat, as expected. Due to the suppressed measure of the throat in the wave function normalization, we find that a KK mode's probability in the bulk can be comparable to that of the graviton mode. We also present the tunneling probabilities of a KK mode from the inflationary throat to the bulk and to another throat. Due to resonance effect, the latter may not be suppressed as natively expected. Implication of this property to reheating after brane inflation is discussed

Modeling DNA Structure, Elasticity and Deformations at the Base-pair Level

We present a generic model for DNA at the base-pair level. We use a variant of the Gay-Berne potential to represent the stacking energy between neighboring base-pairs. The sugar-phosphate backbones are taken into account by semi-rigid harmonic springs with a non-zero spring length. The competition of these two interactions and the introduction of a simple geometrical constraint leads to a stacked right-handed B-DNA-like conformation. The mapping of the presented model to the Marko-Siggia and the Stack-of-Plates model enables us to optimize the free model parameters so as to reproduce the experimentally known observables such as persistence lengths, mean and mean squared base-pair step parameters. For the optimized model parameters we measured the critical force where the transition from B- to S-DNA occurs to be approximately $140{pN}$. We observe an overstretched S-DNA conformation with highly inclined bases that partially preserves the stacking of successive base-pairs.Comment: 15 pages, 25 figures. submitted to PR

Type IIB Solutions with Interpolating Supersymmetries

We study type IIB supergravity solutions with four supersymmetries that interpolate between two types widely considered in the literature: the dual of Becker and Becker's compactifications of M-theory to 3 dimensions and the dual of Strominger's torsion compactifications of heterotic theory to 4 dimensions. We find that for all intermediate solutions the internal manifold is not Calabi-Yau, but has SU(3) holonomy in a connection with a torsion given by the 3-form flux. All 3-form and 5-form fluxes, as well as the dilaton, depend on one function appearing in the supersymmetry spinor, which satisfies a nonlinear differential equation. We check that the fields corresponding to a flat bound state of D3/D5-branes lie in our class of solutions. The relations among supergravity fields that we derive should be useful in studying new gravity duals of gauge theories, as well as possibly compactifications.Comment: 27pp, v2 REVTeX4, typographical fixes and minor clarifications, v3 added ref, modified discussion of RR axion slightl

Computer-aided design of nano-filter construction using DNA self-assembly

Computer-aided design plays a fundamental role in both top-down and bottom-up nano-system fabrication. This paper presents a bottom-up nano-filter patterning process based on DNA self-assembly. In this study we designed a new method to construct fully designed nano-filters with the pores between 5 nm and 9 nm in diameter. Our calculations illustrated that by constructing such a nano-filter we would be able to separate many molecules