Muhagachi Chacha - Academia.edu (original) (raw)

Uploads

Papers by Muhagachi Chacha

Research paper thumbnail of Convection-Free Thermodiffusion in a Water-Ethanol Mixture Subject to Varying Thermal Boundary Conditions

Heat Transfer: Volume 3, 2005

ABSTRACT

Research paper thumbnail of General decay of solutions of a linear one-dimensional porous-thermoelasticity system with a boundary control of memory type

Nonlinear Analysis: Theory, Methods & Applications, 2010

In this paper we consider linear porous-thermoelasticity systems, in a bounded domain, where the ... more In this paper we consider linear porous-thermoelasticity systems, in a bounded domain, where the memory-type damping is acting on a part of the boundary. We establish a general decay result, for which the usual exponential and polynomial decay rates are just special cases. Our work allows certain relaxation functions which are not necessarily of exponential or polynomial decay and, therefore, generalizes and improves on earlier results from the literature.

Research paper thumbnail of A new cinnamoylglycoflavonoid, antimycobacterial and antioxidant constituents fromHeritiera littoralisleaf extracts

Natural Product Research, 2014

A new cinnamolyglycoflavonoid 3-cinnamoyltribuloside (1), its precursor tribuloside and two known... more A new cinnamolyglycoflavonoid 3-cinnamoyltribuloside (1), its precursor tribuloside and two known flavonoid glycosides afzelin and astilbin were isolated from Heritiera littoralis Dryand (Sterculiaceae) ethanolic leaf extract. The dichloromethane leaf extract afforded two known pentacyclic triterpenoids, 3β-taraxerol and friedelin. Extracts and compounds isolated therefrom, with the exception of 3β-taraxerol, exhibited antimycobacterial activity against the non-pathogenic Mycobacterium species Mycobacterium madagascariense and Mycobacterium indicus pranii, with a minimum inhibitory concentration (MIC) 5.0 mg/mL for the crude extracts and MICs in the range of 1.6-0.8 mg/mL for the pure compounds. The extracts together with 3-cinnamoyltribuloside (1), tribuloside and astilbin exhibited 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity. The compounds that showed dual activities could be further evaluated under clinical settings for co-administration with standard anti-tuberculosis drugs.

Research paper thumbnail of Transient convection of Te doped GaSb induced by g-jitter

Journal of Crystal Growth, 2002

Gallium antimonide (GaSb) is commercially used for solar cells and thermophotovoltaic devices. It... more Gallium antimonide (GaSb) is commercially used for solar cells and thermophotovoltaic devices. It is also used as a substrate material for the epitaxial growth of heterostructures, which are used for optoelectronic applications. The semiconducting properties of the material are governed by an antisite defect that requires compensation by a donor dopant such as tellurium to provide n-type conductivity. The electronic

Research paper thumbnail of Compositional Variation Considering Diffusion and Convection for a Binary Mixture …

JOURNAL OF …

In this article we study the compositional variation in a porous cavity having different aspect r... more In this article we study the compositional variation in a porous cavity having different aspect ratios, accounting for natural convection and for thermal, pressure, and molecular diffusion for a binary mixture. The momentum equation is represented by Darcy's law and is solved ...

Research paper thumbnail of Unbalanced transient-based finite-element modeling of large generators

Electric Power Systems Research, 2000

Finite-element modeling is used to study the steady-state and transient performance of a large sy... more Finite-element modeling is used to study the steady-state and transient performance of a large synchronous machine. In the present paper, we carry out a two-dimensional, non-linear, time-stepped finite-element simulation of a line-to-line short circuit on a large salient-pole synchronous generator with multiple rotor circuits under no-load conditions. The work is validated for performance prediction using a Hydro-Québec network generator.

Research paper thumbnail of Convection-Free Thermodiffusion in a Water-Ethanol Mixture Subject to Varying Thermal Boundary Conditions

Heat Transfer: Volume 3, 2005

ABSTRACT

Research paper thumbnail of General decay of solutions of a linear one-dimensional porous-thermoelasticity system with a boundary control of memory type

Nonlinear Analysis: Theory, Methods & Applications, 2010

In this paper we consider linear porous-thermoelasticity systems, in a bounded domain, where the ... more In this paper we consider linear porous-thermoelasticity systems, in a bounded domain, where the memory-type damping is acting on a part of the boundary. We establish a general decay result, for which the usual exponential and polynomial decay rates are just special cases. Our work allows certain relaxation functions which are not necessarily of exponential or polynomial decay and, therefore, generalizes and improves on earlier results from the literature.

Research paper thumbnail of A new cinnamoylglycoflavonoid, antimycobacterial and antioxidant constituents fromHeritiera littoralisleaf extracts

Natural Product Research, 2014

A new cinnamolyglycoflavonoid 3-cinnamoyltribuloside (1), its precursor tribuloside and two known... more A new cinnamolyglycoflavonoid 3-cinnamoyltribuloside (1), its precursor tribuloside and two known flavonoid glycosides afzelin and astilbin were isolated from Heritiera littoralis Dryand (Sterculiaceae) ethanolic leaf extract. The dichloromethane leaf extract afforded two known pentacyclic triterpenoids, 3β-taraxerol and friedelin. Extracts and compounds isolated therefrom, with the exception of 3β-taraxerol, exhibited antimycobacterial activity against the non-pathogenic Mycobacterium species Mycobacterium madagascariense and Mycobacterium indicus pranii, with a minimum inhibitory concentration (MIC) 5.0 mg/mL for the crude extracts and MICs in the range of 1.6-0.8 mg/mL for the pure compounds. The extracts together with 3-cinnamoyltribuloside (1), tribuloside and astilbin exhibited 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity. The compounds that showed dual activities could be further evaluated under clinical settings for co-administration with standard anti-tuberculosis drugs.

Research paper thumbnail of Transient convection of Te doped GaSb induced by g-jitter

Journal of Crystal Growth, 2002

Gallium antimonide (GaSb) is commercially used for solar cells and thermophotovoltaic devices. It... more Gallium antimonide (GaSb) is commercially used for solar cells and thermophotovoltaic devices. It is also used as a substrate material for the epitaxial growth of heterostructures, which are used for optoelectronic applications. The semiconducting properties of the material are governed by an antisite defect that requires compensation by a donor dopant such as tellurium to provide n-type conductivity. The electronic

Research paper thumbnail of Compositional Variation Considering Diffusion and Convection for a Binary Mixture …

JOURNAL OF …

In this article we study the compositional variation in a porous cavity having different aspect r... more In this article we study the compositional variation in a porous cavity having different aspect ratios, accounting for natural convection and for thermal, pressure, and molecular diffusion for a binary mixture. The momentum equation is represented by Darcy's law and is solved ...

Research paper thumbnail of Unbalanced transient-based finite-element modeling of large generators

Electric Power Systems Research, 2000

Finite-element modeling is used to study the steady-state and transient performance of a large sy... more Finite-element modeling is used to study the steady-state and transient performance of a large synchronous machine. In the present paper, we carry out a two-dimensional, non-linear, time-stepped finite-element simulation of a line-to-line short circuit on a large salient-pole synchronous generator with multiple rotor circuits under no-load conditions. The work is validated for performance prediction using a Hydro-Québec network generator.