The trigonal planar Au(I) complex Cs 8 [Au(TPPTS) 3 ]×/5.25H 2 O, TPPTS 0/tris-sulfonatophenyl ph... more The trigonal planar Au(I) complex Cs 8 [Au(TPPTS) 3 ]×/5.25H 2 O, TPPTS 0/tris-sulfonatophenyl phosphine, has been structurally characterized. The X-ray data for the triclinic crystal, P1; are a 0/13.7003(4) Å , b 0/18.0001(6) Å , c 0/18.2817(2) Å , a 0/100.249(2)8, b 0/99.593(2)8, g 0/109.818(2)8, V0/4046.3(2) Å 3 , Z0/2. The complex has Au Ã/P distances of 2.374(6), 2.394(5), and 2.417(5) Å. A network of bonding has been found involving the Cs ' ions, the sulfonate groups of the ligands, and the H 2 O solvent molecules. Luminescence studies of [Au(TPPTS) 3 ] 8(and (TPA) 3 AuCl, TPA 0/1,3,5-triaza-7-phosphaadamantane, in the solid state and in solution are discussed and quenching studies of the luminescence of [Au(TPPTS) 3 ] 8(are reported with alkyl halides and oxygen.
The mono-and dinuclear base-stabilized gold(I) pyrazolate complexes, (PPh 3)Au(l-3,5-Ph 2 pz)) (1... more The mono-and dinuclear base-stabilized gold(I) pyrazolate complexes, (PPh 3)Au(l-3,5-Ph 2 pz)) (1), (TPA)Au(3,5-Ph 2 pz), TPA ¼ 1,3,5-triaza-7-phophaadamantane (2), [(PPh 3) 2 Au(l-3,5-Ph 2 pz)]NO 3 (3) and [(dppp)Au(l-3,5-Ph 2 pz)]NO 3 , dppp ¼ bis-(diphenylphosphino)propane (4), have been synthesized and structurally characterized. The mononuclear gold(I) complexes 1 and 2 show intermolecular AuÁ Á ÁAu interactions of 3.1540(6) and 3.092(6) A, while the dinuclear gold(I) complexes 3 and 4 show an intramolecular AuÁ Á ÁAu distances of 3.3519(7) and 3.109(2) A, respectively, typical of an aurophilic attraction. Complexes 1-4 exhibit luminescence at 77 K when excited with ca. 333 nm UV light with an emission maximum at ca. 454 nm. The emission has been assigned to ligand-to-metal charge transfer, LMCT, based upon the vibronic structure that is observed.
This paper presents an adaptive fuzzy-proportional integral derivative (PID) controller for DC-DC... more This paper presents an adaptive fuzzy-proportional integral derivative (PID) controller for DC-DC boost converters used as voltage regulators in PV systems. This proposed controller maximizes the stable operating range by tuning the PID parameters ultimately at various loading conditions. Then, a fuzzy logic approach is used to add a factor of intelligence to the controller such that it can move among different values of proportional gain (K p), integral gain (K i) and derivative gain (K d) based on the system conditions. This controller allows optimal control of boost converters at any loading condition with no need to retune parameters or possibility of failure. Moreover, the paper presents a novel technique to move between the PI and PID configurations of the controller such that the minimum overshoot and ripple are obtained, which increases the controller applicability for utilization in PV systems supplying sensitive loads. A PV system with a capacity of 1 kW has been simulated and implemented in hardware to examine the proposed controller. Furthermore, this paper discusses the loading limitations in PV systems resulting from switching the power electronic interfaces and transients associated with large loads. These conditions derate the power generation capability of the PV system. We propose some methods to enhance the loadability of these systems under both steady state and dynamic operations. A PV system for home application purposes, with a rated power of 280 W was designed and built to investigate the loadability issue. The proposed enhancements were applied to the experimental setup and the obtained results verified the effectiveness of the proposed methods.
The synthesis of diazonium tetrachloroaurate(III) complexes [R-4-C 6 H 4 N≡N]AuCl 4 involves prot... more The synthesis of diazonium tetrachloroaurate(III) complexes [R-4-C 6 H 4 N≡N]AuCl 4 involves protonation of anilines CN-4-C 6 H 4 NH 2 , C 8 F 17-4-C 6 H 4 NH 2 , and C 6 H 13-4-C 6 H 4 NH 2 with tetrachloroauric acid H[AuCl 4 ] 3H 2 O in acetonitrile followed by one-electron oxidation using [NO]PF 6. FT-IR shows the diazonium stretching frequency at 2277 cm −1 (CN), 2305 cm −1 (C 8 F 17), and 2253 cm −1 (C 6 H 13). Thermogravimetric Analysis (TGA) shows the high stabilities of the electron-withdrawing substituents C 8 F 17 and CN compared with the electron-donating substituent C 6 H 13. Residual Gas Analysis (RGA) shows the release of molecular nitrogen as the main gas residue among other small molecular weight chlorinated hydrocarbons and chlorobenzene. Temperature-Dependent X-Ray Powder Diffraction (TD-XRD) shows the thermal decomposition in C 6 H 13 diffraction patterns at low temperature of 80 °C which supports the TGA and RGA (TGA-MS) conclusions. X-ray structure shows N≡N bond distance of approximately 1.10 Å and N≡N-C bond angle of 178°.
The purpose of this study is to analyze the relationship between crop yields and total chlorophyl... more The purpose of this study is to analyze the relationship between crop yields and total chlorophyll potential of different barley and oats cultivars. For this purpose, we used the spectra of grain crops obtained from ground-based remote sensing, and laboratory data. Ground-based data were obtained at the experimental fields located in the Krasnoyarskii Krai. Experiments were carried out in different seasons and under various lighting conditions. Spectral measurements were done with a double-beam spectrophotometer. It was installed on the mobile work platform at heights of 5 to 18 m. The study showed good correlation between crop yields and total chlorophyll potential for barley and oats cultivars.
Carbon-centered radicals constitute an important and extensively studied group of reactive interm... more Carbon-centered radicals constitute an important and extensively studied group of reactive intermediates. 1 However, despite extensive research the experimental structures of only four types of stable organic radicals have been reported: (1) triarylmethyl radicals 1, with X) NO 2 , 2 halogen; 3 (2) a per-pyridiniumsubstituted allyl radical, 2; 4 (3) the cyclopentadienyl radical, 3; 5 (4) the dodecamethylcarba-closo-dodecaboranyl radical (CB 11-Me 12 •). 6 All of these radicals are strongly stabilized thermodynamically by effective delocalization of the unpaired electron and kinetically by the bulky substituents. 2-6 Bulky alkyl and silyl substituents can reduce the reactivity of simple localized carboncentered radicals to the extend that they become "persistent". 1a,b However, there are no examples of such radicals being a pure crystal.
The trigonal planar Au(I) complex Cs 8 [Au(TPPTS) 3 ]×/5.25H 2 O, TPPTS 0/tris-sulfonatophenyl ph... more The trigonal planar Au(I) complex Cs 8 [Au(TPPTS) 3 ]×/5.25H 2 O, TPPTS 0/tris-sulfonatophenyl phosphine, has been structurally characterized. The X-ray data for the triclinic crystal, P1; are a 0/13.7003(4) Å , b 0/18.0001(6) Å , c 0/18.2817(2) Å , a 0/100.249(2)8, b 0/99.593(2)8, g 0/109.818(2)8, V0/4046.3(2) Å 3 , Z0/2. The complex has Au Ã/P distances of 2.374(6), 2.394(5), and 2.417(5) Å. A network of bonding has been found involving the Cs ' ions, the sulfonate groups of the ligands, and the H 2 O solvent molecules. Luminescence studies of [Au(TPPTS) 3 ] 8(and (TPA) 3 AuCl, TPA 0/1,3,5-triaza-7-phosphaadamantane, in the solid state and in solution are discussed and quenching studies of the luminescence of [Au(TPPTS) 3 ] 8(are reported with alkyl halides and oxygen.
The mono-and dinuclear base-stabilized gold(I) pyrazolate complexes, (PPh 3)Au(l-3,5-Ph 2 pz)) (1... more The mono-and dinuclear base-stabilized gold(I) pyrazolate complexes, (PPh 3)Au(l-3,5-Ph 2 pz)) (1), (TPA)Au(3,5-Ph 2 pz), TPA ¼ 1,3,5-triaza-7-phophaadamantane (2), [(PPh 3) 2 Au(l-3,5-Ph 2 pz)]NO 3 (3) and [(dppp)Au(l-3,5-Ph 2 pz)]NO 3 , dppp ¼ bis-(diphenylphosphino)propane (4), have been synthesized and structurally characterized. The mononuclear gold(I) complexes 1 and 2 show intermolecular AuÁ Á ÁAu interactions of 3.1540(6) and 3.092(6) A, while the dinuclear gold(I) complexes 3 and 4 show an intramolecular AuÁ Á ÁAu distances of 3.3519(7) and 3.109(2) A, respectively, typical of an aurophilic attraction. Complexes 1-4 exhibit luminescence at 77 K when excited with ca. 333 nm UV light with an emission maximum at ca. 454 nm. The emission has been assigned to ligand-to-metal charge transfer, LMCT, based upon the vibronic structure that is observed.
This paper presents an adaptive fuzzy-proportional integral derivative (PID) controller for DC-DC... more This paper presents an adaptive fuzzy-proportional integral derivative (PID) controller for DC-DC boost converters used as voltage regulators in PV systems. This proposed controller maximizes the stable operating range by tuning the PID parameters ultimately at various loading conditions. Then, a fuzzy logic approach is used to add a factor of intelligence to the controller such that it can move among different values of proportional gain (K p), integral gain (K i) and derivative gain (K d) based on the system conditions. This controller allows optimal control of boost converters at any loading condition with no need to retune parameters or possibility of failure. Moreover, the paper presents a novel technique to move between the PI and PID configurations of the controller such that the minimum overshoot and ripple are obtained, which increases the controller applicability for utilization in PV systems supplying sensitive loads. A PV system with a capacity of 1 kW has been simulated and implemented in hardware to examine the proposed controller. Furthermore, this paper discusses the loading limitations in PV systems resulting from switching the power electronic interfaces and transients associated with large loads. These conditions derate the power generation capability of the PV system. We propose some methods to enhance the loadability of these systems under both steady state and dynamic operations. A PV system for home application purposes, with a rated power of 280 W was designed and built to investigate the loadability issue. The proposed enhancements were applied to the experimental setup and the obtained results verified the effectiveness of the proposed methods.
The synthesis of diazonium tetrachloroaurate(III) complexes [R-4-C 6 H 4 N≡N]AuCl 4 involves prot... more The synthesis of diazonium tetrachloroaurate(III) complexes [R-4-C 6 H 4 N≡N]AuCl 4 involves protonation of anilines CN-4-C 6 H 4 NH 2 , C 8 F 17-4-C 6 H 4 NH 2 , and C 6 H 13-4-C 6 H 4 NH 2 with tetrachloroauric acid H[AuCl 4 ] 3H 2 O in acetonitrile followed by one-electron oxidation using [NO]PF 6. FT-IR shows the diazonium stretching frequency at 2277 cm −1 (CN), 2305 cm −1 (C 8 F 17), and 2253 cm −1 (C 6 H 13). Thermogravimetric Analysis (TGA) shows the high stabilities of the electron-withdrawing substituents C 8 F 17 and CN compared with the electron-donating substituent C 6 H 13. Residual Gas Analysis (RGA) shows the release of molecular nitrogen as the main gas residue among other small molecular weight chlorinated hydrocarbons and chlorobenzene. Temperature-Dependent X-Ray Powder Diffraction (TD-XRD) shows the thermal decomposition in C 6 H 13 diffraction patterns at low temperature of 80 °C which supports the TGA and RGA (TGA-MS) conclusions. X-ray structure shows N≡N bond distance of approximately 1.10 Å and N≡N-C bond angle of 178°.
The purpose of this study is to analyze the relationship between crop yields and total chlorophyl... more The purpose of this study is to analyze the relationship between crop yields and total chlorophyll potential of different barley and oats cultivars. For this purpose, we used the spectra of grain crops obtained from ground-based remote sensing, and laboratory data. Ground-based data were obtained at the experimental fields located in the Krasnoyarskii Krai. Experiments were carried out in different seasons and under various lighting conditions. Spectral measurements were done with a double-beam spectrophotometer. It was installed on the mobile work platform at heights of 5 to 18 m. The study showed good correlation between crop yields and total chlorophyll potential for barley and oats cultivars.
Carbon-centered radicals constitute an important and extensively studied group of reactive interm... more Carbon-centered radicals constitute an important and extensively studied group of reactive intermediates. 1 However, despite extensive research the experimental structures of only four types of stable organic radicals have been reported: (1) triarylmethyl radicals 1, with X) NO 2 , 2 halogen; 3 (2) a per-pyridiniumsubstituted allyl radical, 2; 4 (3) the cyclopentadienyl radical, 3; 5 (4) the dodecamethylcarba-closo-dodecaboranyl radical (CB 11-Me 12 •). 6 All of these radicals are strongly stabilized thermodynamically by effective delocalization of the unpaired electron and kinetically by the bulky substituents. 2-6 Bulky alkyl and silyl substituents can reduce the reactivity of simple localized carboncentered radicals to the extend that they become "persistent". 1a,b However, there are no examples of such radicals being a pure crystal.
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Papers by Ahmed Mohamed