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Statistical Analysis of Rain at Millimeter Waves in Tropical Area
(IEEE, 202-03-09) Al-saman, Ahmed; Cheffena, Michael; Mohamed, Marshed; Azmi, Marwan Hadri; Ai, Yun
The high frequencies of millimeter wave (mm-wave) bands have been recognized for the fifth generation (5G) and beyond wireless communication networks. However, the radio propagation channel at high frequencies can be largely influenced by rain attenuation, especially in tropical regions with high rainfall intensity. In this paper, we present the results of rainfall intensity and rain attenuation in tropical regions based on one-year measurement campaign. The measurements were conducted from September 2018 until September 2019 at 21.8 GHz (K-band) and 73.5 GHz (E-band) in Malaysia. The rainfall intensity was collected using three rain gauges installed along a 1.8 km link. The rain attenuation is computed from the difference between the measured minimum received signal level (RSL) during clear sky and rain conditions. The measured rain rate and rain attenuation distributions are then analysed and benchmarked with several previous measurements and well-known prediction models such as the ITU-R P. 530-17. The rainfall rate results showed that the best agreement between the measured rainfall rate in Malaysia and the ITU-R PN.837-1 prediction value for Zone P is up to 0.01% of time (99.99% of time agrees well and only disagrees for 0.01% of time). For the E-band, the maximum measured rain attenuation exceeding 0.03% of the year is around 40.1 and 20 dB for 1.8 and 0.3 km links, respectively, at the maximum rain rate of 108 mm/h. For the K-band, the maximum rain attenuation exceeding 0.01% of the year is around 31 dB for the 1.8 km link. Finally, the rain rates exceeding 108 and 180 mm/h at 73.5 and 21.8 GHz, respectively, along the 1.8 km path caused an outage on our measurement setup. The rain rate of 193 mm/h and above caused an outage for the 0.3 km E-band link. The experimental data as well as the presented data analysis can be utilized for efficient planning and deployments of mm-wave wireless communication systems in tropical regions.
Solubilities of Protein-Antigen/Rabbit-Antibody Complexes as a Measure of Serum Avidity
(Elsevier, 1973) Nicklin, M. G.; Stephen, Josephine K.
Several immunizing schedules were examined for the production of rabbit antibodies to human serum albumin, ovalbumin and lysozyme, having lowered affinities for respective antigens.From those sera which contained precipitating antibodies, antigen/antibody complexes were made at optimum proportions at pH 7.0. The solubilities of such complexes were measured in buffers of constant ionic strenght (0·26) and of pH ranging from 2·5 to 10·0. The use of large quantities of alum-absorbed antigen, administered in small doses (schedule I) yielded sera, complexes derived from which were the most soluble at least extreme pH values. Sera raised with complete Freund's adjuvant (CFA) yielded the least soluble complexes. Administration of large quantities of alum-adsorbed antigens in two dosed produced sera whose complexes were similar to those of CFA sera. Sera taken early in the response to antigen and CFA yielded complexes similar to those of schedule I sera.Attention was focused on the effect of citrate buffer pH 4·0, in dissociating antigen/antibody complexes since at this pH value maximum solubility differences were observed between complexes derived from the greatest number of sera. Where technically possible antisera yielding complexes soluble at pH 4·0 were shown to yield dissociable complexes (by ultracentrifugation), to contain non-precipitating antibodies (by precipitin analysis), and to be non-avid (by the technique of Farr (1985)).
Recovery of Protein Antigens from Disulphide-Linked Immunosorbents Derived from Non-Avid Sera
(Elsevier, 1974) Nicklin, M. G.; Stephen, Josephine K.
Disulphide-linked antibody immunosorbents were prepared from non-avid antisera raised to human serum albumin, ovalbumin and lysozyme. The ease with which homologous antigen was released from such immunosorbents was compared with that from their fully avid counterparts. This was maximally demonstrated using acidic buffers of pH 4–5 and immunosorbent columns in which the disulfide-linked protei was mixed with Sephadex G-15 and placed on top of more Sephadex G-15. Conditions are described under which immunosorbent derived from non-avid sera adsorber and released homologous antigen 3–4 time more efficiently than their avid counterparts.
The Behavior of Antigenically Related Influenza-Viruses of Differing Virulence on Disulfide-Linked Immunosorbents
(1974) Sweet, Clive; Stephen, Josephine K.; Smith, H.
Immunization of Ferrets against Influenza: A Comparison of Killed Ferret Grown and Egg Grown Virus
(1974) Sweet, Clive; Stephen, Josephine K.; Smith, H.
Both killed unadjuvanted ferret and egg grown A/Moscow/1019/65 (H2N2) influenza virus failed to immunize ferrets against challenge with homologous virus: the preparations were given in 2 doses, 2 wk apart, distributed intranasally, intramuscularly and intraperitoneally. However, small doses (<2 HA units) of both preparations induced immunity in ferrets previously 'primed' with a live heterologous virus (A/FM/1/47 (H1N1) according to the method of Potter et al. (1973). Although no difference in immunizing activity was detected between ferret and egg grown virus, the former induced greater HI titres than the latter. There was no correlation between HI titres in serum and protection to challenge: in fact, some protection seemed to be afforded by the 'priming' virus in the absence of HI antibody to the challenge virus. These results are discussed in relation to the possibility that a previously unrecognized antigen different from hemagglutinin and neuraminidase may contribute to immunity to influenza.
Purification of Influenza Viruses using Disulphide-Linked Immunosorbents Derived from Rabbit Antibody
(Elsevier, 1974) Sweet, Clive; Stephen, Josephine K.; Smith, H.
Influenza viruses (A/Moscow/1019/65, A/England/344/68, PR/8-A/Hong kong/68) were specifically adsorbed from crude egg grown suspensions by their homologous disulphide-linked immunosorbents prepared from the γ-globulin of rabbits immunized with influenza virus from calf-kidney tissue cultures.In batch experiments 20 mg of the appropriate ‘non-avid’ immunosorbents (from 4–7 ml of serum taken shortly after one dose of antigen) adsorbed approximately 6 × 109, 3 × 109 and 3 × 1010 egg-bit infective dose50 (approximately 1 × 1012, 1·3 × 1012 and 1·9 × 1012 total particles as indicated by haemagglutination assays) of A/Moscow/1019/65, A/England/344/68 and PR/8-A/Hong Kong/68 respectively; and about 50 per cent of infective virus was eluted with alkaline buffers of pH 11·3, 12·0 and 12·5 respectively. After filtration to remove a trace of immunosorbent the eluted virus suspensions contained 40–91,000 HA/mg protein. ‘Avid’ immunosorbents (prepared from serum taken later after booster injections) had greater capacities (approximately 2–4 times) for infective virus than ‘non-avid’ immunosorbents but only 3–18 per cent of virus could be eluted from them. Both ‘non-avid’ and ‘avid’ immunosorbents adsorbed heterologous viruses of the same or different serotypes to those used to prepare the immunosorbents provided there was some similarity in either the haemagglutinin or neuraminidase antigens. However, their capacities for heterologous viruses were reduced in comparison to those for homologous viruses.Using a column containing a mixture of immunosorbent (100 mg) and Sephadex G-15 approximately 3·5 × 1012 total particles were adsorbed and 50 per cent eluted at each cycle at 5°C. Prior diafiltration of the crude virus suspensions was necessary to prevent column blockage but then the column could be recycled 10 times. The eluted virus suspension had 100,000 HA/mg protein and contained little or no egg or rabbit protein as judged by hypersensitivity reactions in suitably sensitised guinea-pigs.
Energy resources, flows, and end-uses in Tanzania
(Dar es Salaam University Press, 1983, 1983) Mwandosya, Mark J.; Luhanga, Matthew L.
Packet Error Probability for Diversity Systems in Slow Rayleigh Fading and Gaussian Noise
(1986-07) Luhanga, Matthew L.
Analytical results on packet error probability for noncoherent frequency-shift-keying (NCFSK) and differential phase-shift-keying (DPSK) systems with diversity reception operating over slow Rayleigh fading channels with Gaussian noise are derived. Expressions obtained are applicable to two linear combining schemes: selection combining and maximal-ratio combining.
Energy planning and wood balances
(1990-05) Hosier, Richard H.; Boberg, Jill; Luhanga, Matthew L.; Mwandosya, Mark J.
Woodfuel balances are commonly used by energy planners in developing countries to determine the adequacy of woodfuel resources. Recently, critics have argued that wood balances are misleading in their simplicity, exaggerating both the severity of the woodfuel shortage and the need for planned interventions to solve that problem. This paper examines four different wood balances developed for Tanzania. While the four studies all indicate that areas with miombo woodlands are in the greatest wood surplus, the specific estimates for any given region may differ widely. Despite their shortcomings, energy planners need woodfuel balances to give an impression of the adequacy of woodfuel resources. However, if energy planning is to have any effect, these balances must represent the beginning, and not the end result, of the planning process. Planners must follow the wood-energy balance analysis with work utilizing local people to solve local problems.
New impedance transforming rat-race hybrid ring: Electronics Letters
(The Institution of Electrical Engineers, 1990-06-21) Kissaka, Mussa; Mgombelo, H. R.; Ali, H. O.
Increasing the Synchronisation Reliability of a Code-Synchronised Transmission System
(Bergen (Norway), 1991) Kundaeli, Herald N.
Computing and Communications View graph of relations The Design of a Mixed-Mode Integrated Circuit to Implement a New Decoding Algorithm
(HW Communications Limited, 1993) Kissaka, Mussa; King, D.; Markarian, G. S.; Honary, Bahram
Design Parameters for a Bit-Synchronized Transmission System
(Taylor & Francis, 1993) Kundaeli, Herald N.
The transmission reliability of transmission systems that employ synchronization codes For frame synchronization has been analysed in a previous report (Kundaeli 1991) in which it was shown that the introduction of verify states in the synchronization recovery and loss paths of the receiver resulted in increased reliability. Here we extend that analysis to provide a general method for determining the receiver design and performance parameters. We first derive the synchronization efficiency as a new performance parameter, then the applicable number of verify states for a receiver for practical ranges of both the channel error-rate and frame length.
Energy and Development in Tanzania: Issues and Perspectives", Energy Policy
(Elsevier, 1993-05) Mwandosya, Mark J.; Luhanga, Matthew L.
Although per capita consumption of commercial fuels in Tanzania remains low, the energy sector faces a number of difficult challenges. As in most other countries, energy policy formulation takes place in the context of great uncertainty, being the result of pressures exerted by conflicting interests, particularly with respect to fuel pricing. The Tanzania National Energy Policy was recently adopted after a process of studies and public hearings which spanned more than a decade. One of its principal goals is to reduce dependence upon imported petroleum fuels. The reliability of the electricity system and the financial status of the electric utility are also important issues. Despite the fact that many previous authors have emphasized woodfuel problems, at present the problem is limited to localized shortages. One of the most important obstacles facing the energy sector is the shortage of skilled personnel necessary to operate the sector.
Future Energy Development in Tanzania: The Energy Costs of Urbanization
(1993-05) Hosier, Richard H.; Mwandosya, Mark J.; Luhanga, Matthew L.
This paper utilizes the detailed energy balance data developed as part of the Tanzania Urban Energy Project to examine future energy use in Tanzania. The energy costs of urbanization are shown to be quite substantial. National energy balances demonstrate that the urban areas make up a large share of the consumption of all fuels except woodfuel. As urbanization continues into the future, it will be accompanied by dramatic increases in the consumption of petroleum fuels, electricity and charcoal. For example, using base case or business as usual assumptions, over a planning period stretching from 1990 to 2010, every 1% increase in the level of urbanization can be expected to lead to a 12% increase in electricity consumption, a 14% increase in the consumption of all petroleum fuels and a 14% increase in the consumption of charcoal. Finally, the paper examines different energy policy options which are consistent with the stated national energy policy. After the examination of a set of ambitious policy efforts, a set of feasible policies are tested and shown to have a significant impact on the goals of improving efficiency, obtaining the desirable energy consumption profile and conserving indigenous woodfuel resources.
Design Parameters for a Code-Synchronized Transmission System
(Taylor & Francis, 1995) Kundaeli, Herald N.
The reliability of a communication system depends on the design of its receiver, because it is the receiver which has to retrieve the information from the channel with high accuracy even if that information has been corrupted by noise. The design parameters chosen for the receiver are more critical than the other design parameters of the communication system. The design parameters of a code-synchronized communication system are determined. In addition, the role of the synchronization efficiency in determining the design parameters of the receiver is demonstrated.
Pollution in the Manufacturing Sector in Tanzania
(Centre for Energy, Environment, Science & Technology (CEEST), 1995) Mwandosya, Mark J.; Luhanga, Matthew L.
Low-frequency computer-based multiphase variable-amplitude variable-frequency oscillator
(1995-12) Yonah, Z. O.; Kissaka, Mussa; El-Serafi, A. M.; Krause, A. E.
Entropic Thresholding Methods in Reconstruction of Capacitance Tomography Data
(IEEE, 1996) Mwambela, Alfred; Isaksen, O.; Johansen, Geir A.
High quality reconstruction of capacitance tomography data is of vital importance for the extraction of quantitative information from such systems. The use of such soft-field sensor systems and the LBP reconstruction algorithm produces distortions in the reconstructed tomogram data (i.e. the true intensity values and their location in the tomogram under consideration are corrupted or altered). The main problem with LBP reconstruction algorithm is a smearing effect of sharp transitions in the dielectric constants. Several authors have suggested different approaches for improving the quality of the reconstructed tomogram. The quality of the generated tomograms could be improved by including a thresholding procedure in the reconstruction process for the purpose of minimising these distortions. Here, the use of global entropic thresholding methods in the reconstruction process of capacitance tomography data is reported. The results obtained are compared to the previously published thresholding methods of Xie et al. (1992) and an Implicit Model based reconstruction. It is concluded that distortions in the reconstructed capacitance tomograms can be minimised by using a thresholding procedure. It can be seen that the evaluated global entropic thresholding methods without supervision cannot be used to produce reasonably accurate results when it comes to multicomponent flow imaging. The smearing effect of the LBP reconstruction algorithms blur the phase transition making it hard for autothresholding, particularly for small objects. This effect is more pronounced when the two components under investigation have a small difference in permitivity
Environmental Protection and Sustainable Development, Centre Technology
(Centre for Energy, Environment, Science, and Technology, 1996, 1996) Mwandosya, Mark J.; Luhanga, Matthew L.; Mugurus, Eric K.

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