Benchmarking leakage from water reticulation systems in South Africa

A project to assess the levels of leakage in 30 water utilities throughout South Africa was initiated by the Water Research Commission. The BENCHLEAK software was used to evaluate the water utilities and performance indicators calculated by the model were used to compare levels of non-revenue water. Results showed that utilities ranked differently according to the different indicators, and that the South African results are similar to world norms. Feed back from the water utilities showed that some of the data requested were confusing and required clarity. The number of service connections, apparent losses and length of pipe between the street edge and the meter were looked at in more detail. Standard drawings were developed to assist water utilities in determining their number of service connections. A table is presented to assess the apparent losses of each water utility in a more pragmatic way. Water SA Vol. 30 (5) 2005: pp.25-3

Multi-band optical variability of three TeV Blazars on Diverse Timescales

We present our optical photometric observations of three TeV blazars, PKS 1510-089, PG 1553+113 and Mrk 501 taken using two telescopes in India, one in Bulgaria, one in Greece and one in Serbia during 2012 - 2014. These observations covered a total of 95 nights with a total of 202 B filter frames, 247 images in V band, 817 in R band while 229 images were taken in the I filter. This work is focused on multi-band flux and colour variability studies of these blazars on diverse timescales which are useful in understanding the emission mechanisms. We studied the variability characteristics of above three blazars and found all to be active over our entire observational campaigns. We also searched for any correlation between the brightness of the sources and their colour indices. During the times of variability, no significant evidence for the sources to display spectral changes correlated with magnitude was found on timescales of a few months. We briefly discuss the possible physical mechanisms most likely responsible for the observed flux variability.Comment: 11 pages, 7 figures, 9 tables. Accepted for publication in MNRA

Understanding the Session Durability in Peer-to-Peer Storage System

This paper emphasizes that instead of long-term availability and reliability, the short-term session durability analysis will greatly impact the design of the real large-scale Peer-to-Peer storage system. In this paper, we use a Markov chain to model the session durability, and then derive the session durability probability distribution. Subsequently, we show the difference between our analysis and the traditional Mean Time to Failure (MTTF) analysis, from which we conclude that the misuse of MTTF analysis will greatly mislead our understanding of the session durability. We further show the impact of session durability analysis on the real system design. To our best knowledge, this is the first time ever to discuss the effects of session durability in large-scale Peer-to-Peer storage system.Computer Science, Theory & MethodsSCI(E)EICPCI-S(ISTP)

Syntheses, spectral, thermal and pH-metric studies on bivalent metal ion complexes of N,N’-bis(3-carboxy-1-oxo-z-prop-2-elenyl)ethylenediamine

A novel carboxyamide ligand has been synthesized using maleic anhydride and ethylenediamine. Co(II), Ni(II), Cu(II) and Pd(II) complexes of the ligand, i.e., N,N’-bis(3-carboxy-1-oxo-z-prop-2-elenyl)ethylenediamine [H2L] have been prepared and characterized by elemental analyses,  IR, electronic, 1H NMR, EPR spectral and thermal studies. It is revealed by IR and 1H NMR spectral studies that the ligand coordinated to the metal ions through deprotonated carboxylate oxygen and non-deprotonated amide nitrogen in all the complexes. It is suggested by electronic spectral and magnetic moment studies that N2O2 coordination is around each metal center with a strong field square planar chromophore. All the complexes have been studied by TGA and DTA studies done simultaneously. The complex formation between ligand and metal ions [Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)] has also been studied pH metrically in 75% aqueous DMF solution at 298 K in 0.1 M NaClO4. The probable structures of the complexes have also been proposed

Economic benefit of ensuring uninterrupted water supply during prolonged electricity disruptions – City of Tshwane case study

Mitigating the impact of electricity disruptions on water supply was investigated as a case study on the City of Tshwane. This study found that current institutional arrangements between electricity suppliers (Eskom), water service providers and water service authorities are insufficient. Therefore, a Risk Analysis and Mitigation Framework of Integrated Water and Electricity Systems, or RAMFIWES, was developed. Risks associated with water supply interruptions due to electricity disruption events were analysed. Risk categories that were addressed are short-term disruptions of less than one day, medium-term disruptions of up to a week and long-term electricity disruptions up to a month or even longer. The direct economic benefits of ensuring uninterrupted water supply in the event of electricity disruption events were analysed through cost versus benefit analyses. It was found that the direct benefit/cost ratio of supplying water during electricity disruption events is 5.6 for wet-industries and an exceptional 117 for other economic sectors in Tshwane. The overall benefit/cost ratio is 15.5. This benefit is possible at a low increase in the normal municipal bills of only 0.5%.The Water Research Commissionhttp://www.journals.co.za/ej/ejour_civileng.htmlCivil Engineerin

Development of new all-optical signal regeneration technique

All-optical signal regeneration have been the active research area since last decade due to evolution of nonlinear optical signal processing. Existing all-optical signal regeneration techniques are agitated in producing low Bit Error Rate (BER) of 10-10 at below than -10 dBm power received. In this paper, a new all-optical signal regeneration technique is developed by using phase sensitive amplification and designed optical phase locked signal mechanism. The developed all-optical signal regeneration technique is tested for different 10 Gb/s Differential Phase Shift Keying degraded signals. It is determined that the designed all-optical signal regeneration technique is able to provide signal regeneration with noise mitigation for degraded signals. It is analyzed that overall, for all degraded test signals, average BER of 10-13 is achieved at received power of -14 dBm. The designed technique will be helpful to enhance the performance of existing signal regeneration systems in the presence of severe noise by providing minimum BER at low received power

Treatment outcomes of patients with MDR-TB in Nepal on a current programmatic standardised regimen:retrospective single-centre study

OBJECTIVES: The objectives of this study were to evaluate treatment in patients on current programmatic multidrug-resistant tuberculosis (MDR-TB) regimen and verify eligibility for the 9-month regimen and therapeutic drug monitoring (TDM). METHODS: We performed a retrospective chart review of patients with MDR-TB receiving standardised regimen at the German Nepal TB Project Clinic, Nepal, between 2014 and 2016. Eligibility for the 9-month regimen and indications for TDM were evaluated. RESULTS: Out of 107 available patients' medical records, 98 were included. In this centre, the MDR-TB treatment success rates were 69.0% in 2015, 86.6% in 2016 and 86.5% in 2017. The median time to sputum smear conversion was 60 days (60-90 IQR) and culture conversion was 60 days (60-90 IQR). Observed side effects did not impact treatment outcomes. No difference in treatment success rates was observed between patients with predisposing risk factors and those without. Only 49% (36/74) of patients were eligible for the 9-month regimen and 23 patients for TDM according to American Thoracic Society guideline criteria. CONCLUSIONS: Nepalese patients with MDR-TB on ambulatory care had good treatment outcome after programmatic treatment. Implementation of the new WHO oral MDR-TB treatment regimen may further improve treatment results. The 9-month regimen and TDM should be considered as part of programmatic care