The lifetime of a carrier is a crucial parameter for solar cell materials, and metal halide perov... more The lifetime of a carrier is a crucial parameter for solar cell materials, and metal halide perovskite materials are promising for solar cell applications. In this study, we observed carrier recombination using time-resolved photoluminescence (TR-PL) and microwave photoconductivity decay (μ-PCD) in metal halide perovskite materials: NH3CH3PbI3 (MAPbI3), NH3CH3PbBr3 (MAPbBr3), and CsPbBr3 with single- and poly-crystalline structures. By comparing the decay curves of TR-PL and μ-PCD, we found trap levels in the band gap for all the materials. We employed two excitation wavelengths for the μ-PCD measurements, and we observed faster μ-PCD signal decays for short wavelength excitation for MAPbBr3 and CsPbBr3. Additionally, we established that the poly-crystals exhibited faster decay compared with the single crystals for MAPbBr3 and CsPbBr3. Therefore, we concluded that there are significant contributions of the interface and surface recombination on carrier recombination for MAPbBr3 and ...
This work highlights the transport situation in South Ubangi Province and the impact on the devel... more This work highlights the transport situation in South Ubangi Province and the impact on the development of this. It is noted that the main modes of transport found in South Ubangi are roads, inland waterways, and airways. The first category is more popular, the second category is seasonal, depending on the water level, and the last category is still a luxury. In all cases, infrastructure, equipment and transport operations leave something to be desired. This has a negative impact on the growth of the company (business) in this province and indirectly, its socio-economic development pays the costs. Therefore, this research aims at assessing the realities of transport in order to help find solutions to the current business companies’ problems operating in this province. The research design used is descriptive based on secondary data. The outcomes of the analysis help policy makers to work on beneficial policies for the province.
La notion de super symétrie constitue un cadre élégant pour la résolution de l’équation de Schröd... more La notion de super symétrie constitue un cadre élégant pour la résolution de l’équation de Schrödinger à une dimension. Elle une méthode systématique de factorisation de l’hamiltonien par l’introduction d’opérateurs échelles. Ce formalisme repose entièrement sur la définition d’un superpotentiel. Des généralisations en dimension d ont déjà été données ; ainsi qu’une extension aux solutions des équations relativistes Klein-Gordon et de Dirac. Dans le domaine de la physique des particules élémentaires ; de charge Q ̂ et Q ̂^+ transforment un boson en un fermion de même énergie donc de même masse et inversement .Si la super symétrie est une symétrie de la nature ; à toute particule doit donc correspondre un superpartenaire de même masse et dont le spin diffère deℏ/2. La perspective d’une pléthore de nouvelle particules à découvrir et l’enthousiasme des spécialistes de susy a conduit un moment à voir dans le neutrino le super partenaire du photon. Malheureusement ; il n’existe qu’un seul photon et trois types de neutrino ; aussi ; à l’heure actuelle ; aucun superpartenaire n’a été identifié. Qu’à cela ne tienne il suffit de supposer que les super particules sont excessivement instables et qu’il n’en reste plus de nos jours ; ou encore la susy est ; brisée ; c'est-à-dire que le superpartenaire ont des masses différentes des particules initiales et qu’elles peuvent ainsi s’avérer si lourdes qu’elles s’échappent aux possibilités des accélérateurs de particules actuels. En tout état de cause ; même si la super symétrie n’est qu’une construction de l’esprit ;si elle n’existe pas dans la nature ; c’est tout de même une idée meilleur et séduisantes. ___________________________________________________________________________ The concept of supersymmetry is an elegant setting for solving the Schrödinger equation in one dimension. It factorization systematic method of the Hamiltonian by introducing scales operators. This formalism is based entirely on the definition of a superpotential. Generalizations in dimension have already been given; and an extension to the solutions of relativistic equations Klein-Gordon and Dirac. In the field of elementary particle physics; load Q and Q ^ + transform a boson into a fermion energy even so the same mass and vice versa .If supersymmetry is a symmetry of nature; any particle must match one of the same mass and superpartner whose spin differs deℏ / 2. The prospect of a plethora of new particles to discover and enthusiasm of specialists susy led a moment to see the neutrino super partner of the photon. Sadly ; there is a single photon and three types of neutrino; also ; at the present time; no superpartner were identified. Never mind simply assume that super particles are excessively volatile and that he remains today; or the susy is; broken; that is to say, the superpartner have different masses of the initial particles and may thus be so heavy that they are immune from the possibility of current particle accelerators. In any case ; even if supersymmetry is only a construct of the mind; if it does not exist in nature; it's still a better idea and attractive.
Structural investigations showed that its crystal structure influences the hydrogen storage prope... more Structural investigations showed that its crystal structure influences the hydrogen storage properties of magnesium hydride. The crystal structure and dehydriding temperature of magnesium hydride activated by high energy ball milling under an argon atmosphere were studied. The XRD characterization showed that a small amount of tetragonal 𝜶-MgH2 phase transforms into nano-crystalline 𝜸- MgH2 of the orthorhombic structure during milling and 𝜸- MgH2 peak intensity was lower than 𝜶-MgH2 one and increased with increasing ball-milling time and speed, but 𝜸- MgH2 disappeared early in the hydrogenation cycle at more than 300oC. We studied the phase structure and the stability of the hydrogenation and dehydrogenation cycles in the context of sustainable use of MgH2.
Magnesium hydride (MgH2) is a prospective material for the storage of hydrogen in solid materials... more Magnesium hydride (MgH2) is a prospective material for the storage of hydrogen in solid materials. It can also be envisaged for thermal energy storage applications since it has the potential to reversibly absorb hydrogen in large quantities, theoretically up to 7.6% by weight. Also, MgH2 is inexpensive, abundant, and environmentally friendly, but it operates at relatively high temperatures, and the kinetics of the hydrogenation process is slow. Mechanical milling and the addition of catalyst can alter the activation energy and the kinetic properties of the MgH2 phase. It is known that the addition of titanium hydride (TiH2) lowers the enthalpy and enhances the absorption of hydrogen from MgH2, titanium oxide (TiO2) enhances the desorption of hydrogen and niobium oxide (Nb2O5) enhances the absorption of hydrogen. In this work, the influences of the catalysts, as mentioned above on the properties of MgH2, were studied. The samples were analyzed in terms of crystal and microstructure a...
Structural investigations showed that its crystal structure influences the hydrogen storage prope... more Structural investigations showed that its crystal structure influences the hydrogen storage properties of magnesium hydride. The crystal structure and dehydriding temperature of magnesium hydride activated by high energy ball milling under an argon atmosphere were studied. The XRD characterization showed that a small amount of tetragonal 𝜶-MgH2 phase transforms into nano-crystalline 𝜸- MgH2 of the orthorhombic structure during milling and 𝜸- MgH2 peak intensity was lower than 𝜶-MgH2 one and increased with increasing ball-milling time and speed, but 𝜸- MgH2 disappeared early in the hydrogenation cycle at more than 300oC. We studied the phase structure and the stability of the hydrogenation and dehydrogenation cycles in the context of sustainable use of MgH2.
ABSTRACT: This work highlights the transport situation in South Ubangi Province and the impact on... more ABSTRACT: This work highlights the transport situation in South Ubangi Province and the impact on the development of this. It is noted that the main modes of transport found in South Ubangi are roads, inland waterways, and airways. The first category is more popular, the second category is seasonal, depending on the water level, and the last category is still a luxury. In all cases, infrastructure, equipment and transport operations leave something to be desired. This has a negative impact on the growth of the company (business) in this province and indirectly, its socio-economic development pays the costs. Therefore, this research aims at assessing the realities of transport in order to help find solutions to the current business companies’ problems operating in this province. The research design used is descriptive based on secondary data. The outcomes of the analysis help policy makers to work on beneficial policies for the province.
ABSTRACT
The excitation functions for several residues produced in the system 20Ne+59Co have been... more ABSTRACT The excitation functions for several residues produced in the system 20Ne+59Co have been studied in the energies range 62.9-150.2 MeV. The experimental excitation functions have been compared with those calculated using computer code PACE4 and COMPLET. The experimental studied production cross-sections for non-alpha emitting channels were found to be in good agreement with theoretical predictions which may be attributed to the complete fusion (CF) processes. However in case of alpha emitting channels, there are signatures of incomplete fusion for more than two alphas emitting and pre-equilibrium for alpha emitting reactions.
The lifetime of a carrier is a crucial parameter for solar cell materials, and metal halide perov... more The lifetime of a carrier is a crucial parameter for solar cell materials, and metal halide perovskite materials are promising for solar cell applications. In this study, we observed carrier recombination using time-resolved photoluminescence (TR-PL) and microwave photoconductivity decay (μ-PCD) in metal halide perovskite materials: NH3CH3PbI3 (MAPbI3), NH3CH3PbBr3 (MAPbBr3), and CsPbBr3 with single- and poly-crystalline structures. By comparing the decay curves of TR-PL and μ-PCD, we found trap levels in the band gap for all the materials. We employed two excitation wavelengths for the μ-PCD measurements, and we observed faster μ-PCD signal decays for short wavelength excitation for MAPbBr3 and CsPbBr3. Additionally, we established that the poly-crystals exhibited faster decay compared with the single crystals for MAPbBr3 and CsPbBr3. Therefore, we concluded that there are significant contributions of the interface and surface recombination on carrier recombination for MAPbBr3 and ...
This work highlights the transport situation in South Ubangi Province and the impact on the devel... more This work highlights the transport situation in South Ubangi Province and the impact on the development of this. It is noted that the main modes of transport found in South Ubangi are roads, inland waterways, and airways. The first category is more popular, the second category is seasonal, depending on the water level, and the last category is still a luxury. In all cases, infrastructure, equipment and transport operations leave something to be desired. This has a negative impact on the growth of the company (business) in this province and indirectly, its socio-economic development pays the costs. Therefore, this research aims at assessing the realities of transport in order to help find solutions to the current business companies’ problems operating in this province. The research design used is descriptive based on secondary data. The outcomes of the analysis help policy makers to work on beneficial policies for the province.
La notion de super symétrie constitue un cadre élégant pour la résolution de l’équation de Schröd... more La notion de super symétrie constitue un cadre élégant pour la résolution de l’équation de Schrödinger à une dimension. Elle une méthode systématique de factorisation de l’hamiltonien par l’introduction d’opérateurs échelles. Ce formalisme repose entièrement sur la définition d’un superpotentiel. Des généralisations en dimension d ont déjà été données ; ainsi qu’une extension aux solutions des équations relativistes Klein-Gordon et de Dirac. Dans le domaine de la physique des particules élémentaires ; de charge Q ̂ et Q ̂^+ transforment un boson en un fermion de même énergie donc de même masse et inversement .Si la super symétrie est une symétrie de la nature ; à toute particule doit donc correspondre un superpartenaire de même masse et dont le spin diffère deℏ/2. La perspective d’une pléthore de nouvelle particules à découvrir et l’enthousiasme des spécialistes de susy a conduit un moment à voir dans le neutrino le super partenaire du photon. Malheureusement ; il n’existe qu’un seul photon et trois types de neutrino ; aussi ; à l’heure actuelle ; aucun superpartenaire n’a été identifié. Qu’à cela ne tienne il suffit de supposer que les super particules sont excessivement instables et qu’il n’en reste plus de nos jours ; ou encore la susy est ; brisée ; c'est-à-dire que le superpartenaire ont des masses différentes des particules initiales et qu’elles peuvent ainsi s’avérer si lourdes qu’elles s’échappent aux possibilités des accélérateurs de particules actuels. En tout état de cause ; même si la super symétrie n’est qu’une construction de l’esprit ;si elle n’existe pas dans la nature ; c’est tout de même une idée meilleur et séduisantes. ___________________________________________________________________________ The concept of supersymmetry is an elegant setting for solving the Schrödinger equation in one dimension. It factorization systematic method of the Hamiltonian by introducing scales operators. This formalism is based entirely on the definition of a superpotential. Generalizations in dimension have already been given; and an extension to the solutions of relativistic equations Klein-Gordon and Dirac. In the field of elementary particle physics; load Q and Q ^ + transform a boson into a fermion energy even so the same mass and vice versa .If supersymmetry is a symmetry of nature; any particle must match one of the same mass and superpartner whose spin differs deℏ / 2. The prospect of a plethora of new particles to discover and enthusiasm of specialists susy led a moment to see the neutrino super partner of the photon. Sadly ; there is a single photon and three types of neutrino; also ; at the present time; no superpartner were identified. Never mind simply assume that super particles are excessively volatile and that he remains today; or the susy is; broken; that is to say, the superpartner have different masses of the initial particles and may thus be so heavy that they are immune from the possibility of current particle accelerators. In any case ; even if supersymmetry is only a construct of the mind; if it does not exist in nature; it's still a better idea and attractive.
Structural investigations showed that its crystal structure influences the hydrogen storage prope... more Structural investigations showed that its crystal structure influences the hydrogen storage properties of magnesium hydride. The crystal structure and dehydriding temperature of magnesium hydride activated by high energy ball milling under an argon atmosphere were studied. The XRD characterization showed that a small amount of tetragonal 𝜶-MgH2 phase transforms into nano-crystalline 𝜸- MgH2 of the orthorhombic structure during milling and 𝜸- MgH2 peak intensity was lower than 𝜶-MgH2 one and increased with increasing ball-milling time and speed, but 𝜸- MgH2 disappeared early in the hydrogenation cycle at more than 300oC. We studied the phase structure and the stability of the hydrogenation and dehydrogenation cycles in the context of sustainable use of MgH2.
Magnesium hydride (MgH2) is a prospective material for the storage of hydrogen in solid materials... more Magnesium hydride (MgH2) is a prospective material for the storage of hydrogen in solid materials. It can also be envisaged for thermal energy storage applications since it has the potential to reversibly absorb hydrogen in large quantities, theoretically up to 7.6% by weight. Also, MgH2 is inexpensive, abundant, and environmentally friendly, but it operates at relatively high temperatures, and the kinetics of the hydrogenation process is slow. Mechanical milling and the addition of catalyst can alter the activation energy and the kinetic properties of the MgH2 phase. It is known that the addition of titanium hydride (TiH2) lowers the enthalpy and enhances the absorption of hydrogen from MgH2, titanium oxide (TiO2) enhances the desorption of hydrogen and niobium oxide (Nb2O5) enhances the absorption of hydrogen. In this work, the influences of the catalysts, as mentioned above on the properties of MgH2, were studied. The samples were analyzed in terms of crystal and microstructure a...
Structural investigations showed that its crystal structure influences the hydrogen storage prope... more Structural investigations showed that its crystal structure influences the hydrogen storage properties of magnesium hydride. The crystal structure and dehydriding temperature of magnesium hydride activated by high energy ball milling under an argon atmosphere were studied. The XRD characterization showed that a small amount of tetragonal 𝜶-MgH2 phase transforms into nano-crystalline 𝜸- MgH2 of the orthorhombic structure during milling and 𝜸- MgH2 peak intensity was lower than 𝜶-MgH2 one and increased with increasing ball-milling time and speed, but 𝜸- MgH2 disappeared early in the hydrogenation cycle at more than 300oC. We studied the phase structure and the stability of the hydrogenation and dehydrogenation cycles in the context of sustainable use of MgH2.
ABSTRACT: This work highlights the transport situation in South Ubangi Province and the impact on... more ABSTRACT: This work highlights the transport situation in South Ubangi Province and the impact on the development of this. It is noted that the main modes of transport found in South Ubangi are roads, inland waterways, and airways. The first category is more popular, the second category is seasonal, depending on the water level, and the last category is still a luxury. In all cases, infrastructure, equipment and transport operations leave something to be desired. This has a negative impact on the growth of the company (business) in this province and indirectly, its socio-economic development pays the costs. Therefore, this research aims at assessing the realities of transport in order to help find solutions to the current business companies’ problems operating in this province. The research design used is descriptive based on secondary data. The outcomes of the analysis help policy makers to work on beneficial policies for the province.
ABSTRACT
The excitation functions for several residues produced in the system 20Ne+59Co have been... more ABSTRACT The excitation functions for several residues produced in the system 20Ne+59Co have been studied in the energies range 62.9-150.2 MeV. The experimental excitation functions have been compared with those calculated using computer code PACE4 and COMPLET. The experimental studied production cross-sections for non-alpha emitting channels were found to be in good agreement with theoretical predictions which may be attributed to the complete fusion (CF) processes. However in case of alpha emitting channels, there are signatures of incomplete fusion for more than two alphas emitting and pre-equilibrium for alpha emitting reactions.
Magnesium hydride is a prospective material for hydrogen storage in solid-state materials. It can... more Magnesium hydride is a prospective material for hydrogen storage in solid-state materials. It can be also considered for thermal energy storage applications because, it has the potential to reversibly absorb hydrogen in large quantities, theoretically up to 7.6 wt. %. Moreover, MgH2 is cheap, abundant, and environment-friendly, but it operates at relatively high temperature and the kinetics of the hydrogenation process are slow. The activation energy and kinetic properties of the MgH2 phase can be altered by the mechanical milling and catalyst addition. It is known that the addition of TiH2 lowers the enthalpy and enhances hydrogen absorption of MgH2, TiO2 enhances hydrogen desorption, and Nb2O5 enhances hydrogen absorption. In this work we study and influence of abovementioned catalyst on properties of MgH2. The samples were studied in terms of their crystal and microstructure as well as hydrogen storage properties using the pressure composition temperature method (PCT). It has been found that the simultaneous addition of all tree catalysis improves MgH2 properties; lowers the activation energy and operating temperature, and increases the speed of a hydrogen release and uptake.
Structural investigations showed that hydrogen storage properties of magnesium hydride are influe... more Structural investigations showed that hydrogen storage properties of magnesium hydride are influenced by its crystal structure. The crystal structure and dehydriding temperature of magnesium hydride activated by high energy ball milling under an argon atmosphere were studied. The XRD characterization showed that a small amount of tetragonal 𝜶-MgH2 phase transform into nano-crystalline 𝜸- MgH2 of orthorhombic structure during milling and 𝜸- MgH2 peak intensity was lower than 𝜶-MgH2 one and increased with increasing ball milling time and speed but 𝜸- MgH2 disappeared early in the hydrogenation cycle at more than 300oC. We studied the phase structure, and the stability of the hydrogenation and dehydrogenation cycles in a context of sustainable use of MgH2.
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Papers by NTUMBA LOBO
is noted that the main modes of transport found in South Ubangi are roads, inland waterways, and airways. The first category
is more popular, the second category is seasonal, depending on the water level, and the last category is still a luxury.
In all cases, infrastructure, equipment and transport operations leave something to be desired. This has a negative impact on
the growth of the company (business) in this province and indirectly, its socio-economic development pays the costs.
Therefore, this research aims at assessing the realities of transport in order to help find solutions to the current business
companies’ problems operating in this province. The research design used is descriptive based on secondary data. The
outcomes of the analysis help policy makers to work on beneficial policies for the province.
Thesis Chapters by NTUMBA LOBO
The excitation functions for several residues produced in the system 20Ne+59Co have been studied in the energies range 62.9-150.2 MeV. The experimental excitation functions have been compared with those calculated using computer code PACE4 and COMPLET.
The experimental studied production cross-sections for non-alpha emitting channels were found to be in good agreement with theoretical predictions which may be attributed to the complete fusion (CF) processes. However in case of alpha emitting channels, there are signatures of incomplete fusion for more than two alphas emitting and pre-equilibrium for alpha emitting reactions.
is noted that the main modes of transport found in South Ubangi are roads, inland waterways, and airways. The first category
is more popular, the second category is seasonal, depending on the water level, and the last category is still a luxury.
In all cases, infrastructure, equipment and transport operations leave something to be desired. This has a negative impact on
the growth of the company (business) in this province and indirectly, its socio-economic development pays the costs.
Therefore, this research aims at assessing the realities of transport in order to help find solutions to the current business
companies’ problems operating in this province. The research design used is descriptive based on secondary data. The
outcomes of the analysis help policy makers to work on beneficial policies for the province.
The excitation functions for several residues produced in the system 20Ne+59Co have been studied in the energies range 62.9-150.2 MeV. The experimental excitation functions have been compared with those calculated using computer code PACE4 and COMPLET.
The experimental studied production cross-sections for non-alpha emitting channels were found to be in good agreement with theoretical predictions which may be attributed to the complete fusion (CF) processes. However in case of alpha emitting channels, there are signatures of incomplete fusion for more than two alphas emitting and pre-equilibrium for alpha emitting reactions.