Development of Generalised Integrator with a Feedback Loop Based Dynamic Voltage Restorer for Fast Mitigation of Voltage Sag/Swell

Power-electronic converter-based device called the Dynamic Voltage Restorer (DVR) is intended to shield delicate loads from supply-side voltage perturbations. It is connected in series to the distribution feeder and has the ability to generate or absorb real and reactive power at its AC terminals. This work presents the use of a control scheme based on Generalized Integrator with a Feedback Loop (GIFL) gain choosing technique for the purpose of fast voltage sag/swell detection to enable the DVR to carry out a fast and effective voltage compensation in power distribution system. This helps in significantly reducing the impact of voltage sag/ swell and in turn improve the power quality of the system. Two scenarios were used to analyze the effectiveness of the developed technique: incorporation of voltage sag and swell independently on the distribution system. The results obtained showed that the distortions introduced to the system as a result of the sag and swell was significantly reduced. The results obtained from the developed scheme was further compared with that obtained when the conventional DVR was used in mitigating the voltage sag and swell using total harmonic distortion (THD) as performance metrics. All modelling and analyses were carried out using MATLAB 2019 software

The use of dye to detect sites of hemorrhage and leak in postmortem cases

This study introduces a novel, cost-effective, and rapid method for identifying hemorrhage or leakage sites following postoperative deaths, a critical aspect in the context of medical malpractice litigation. The technique employs diluted ink as an injectable dye, providing an alternative to postmortem contrast imaging. The utility of this method was demonstrated through a series of three cases. In the first case, the technique successfully detected leaks within vascular structures. The second case revealed a leakage in the cystic duct, while in the third case, the method was instrumental in identifying a leak in a hollow organ situated below the gastro-esophageal junction. Given its demonstrated efficacy, this technique has been incorporated into routine practice by the forensic pathologist in the medicolegal directorate in Baghdad, Iraq

Galvanized Steel as a Sustainable Material-Technology and Failure Analysis

The building industry is responsible for 40% of global CO2 emissions and 36% of global energy consumption. Therefore, it is not surprising that the industry is motivated to embrace more environment-friendly procedures and turning to more environment-friendly materials and manufacturing processes. Driven by ever-stricter environmental norms and regulations, as well as rising costs, galvanizing is considered as an affordable, again, an environment-friendly and 'green' corrosion protection method. In order to prevent corrosion and produce a tough, long-lasting surface, clean steel is coated with a layer of molten zinc during the hot-dip galvanizing process. It has the extra benefit of completely covering the steel, making it more durable than conventional coatings that just adhere chemically or mechanically. As a result, it is not only very efficient but also very environment-friendly. A single, one-time treatment will completely coat a product's interior and exterior, giving it a coating that can shield steel and keep it from needing maintenance for more than 70 years. In this paper, galvanizing will be introduced as an efficient, affordable, and environment-friendly anti-corrosion method. Technical issues related to the process are presented and challenges associated with galvanizing are addressed. The experimental part includes measuring the zinc coating layer using optical microscopy. Failure cases related to galvanized structures which include bridges, bolts, and fire affected monopole are discussed, root causes were analyzed, and recommendations are provided

Impact of Different Fine Aggregates on the Compressive Strength of Hollow Sandcrete Blocks

Sandcrete blocks are walling materials that are made of fine aggregates and cement. Though, sandcrete blocks are being used as building materials in many parts of Nigeria, it has been discovered that many of the blocks produced do not conform to the minimum compressive strength requirement for such blocks. This study, therefore, examined the effect of using four (4) different fine aggregates (quarry dust, river sand, shocking sand and plastering sand) with binder to aggregate mix ratios of 1:6 and 1:4 on the compressive strength of sandcrete blocks. Specific gravity and particle size distribution analyses were conducted on the fine aggregates to determine their properties while water absorption capacity and compressive strength tests were carried out on the hollow sandcrete blocks. Five samples from each aggregate of size 450 mm x 225 mm x 225 mm were moulded and subjected to compressive strength tests. The water absorption capacity results revealed that shocking sand has the highest capacity to absorb water with a value of 8.69 %. River sand, with a value of 6.67 % has the lowest water absorption capacity. The 28th day compressive strength test results of 1.31 N/mm2, 1.10 N/mm2, 0.78 N/mm2 and 0.50 N/mm2 for the sandcrete blocks produced from quarry dust, river sand, shocking sand and plastering sand respectively, with mix ratio 1:6, did not meet the minimum requirement of 2.5 N/mm2 specified by NIS 87:2007 for non-load bearing walls. However, with mix ratio of 1:4, the compressive strength of 2.52 N/mm2 and 2.50 N/mm2 for sandcrete blocks made with quarry dust and river sand respectively met this minimum requirement. It was concluded that only quarry dust and sharp sand at mix ratio 1:4 are suitable in the production of sandcrete blocks

Surveillance of the spread of avian influenza virus type A in live bird markets in Tripoli, Libya, and determination of the associated risk factors

Background and Aim: Studies on avian influenza virus (AIV) in Libya are few and limited. This study aimed to determine the presence of AIV in live bird markets (LBMs) in Tripoli and determine the risk factors associated with AIV spread. Materials and Methods: In total, 269 cloacal swabs were randomly collected from different bird species in 9 LBMs located in Tripoli and its surrounding regions. The target species were ducks, geese, local chickens, Australian chickens, Brahma chickens, turkeys, pigeons, quails, peacock broiler chicks, and pet birds. Total RNA was extracted from the swab samples and used for real-time polymerase chain reaction to detect AIV type A. Results: Of the 269 samples, 28 (10.41% of total samples) were positive for AIV type A. The LBMs with positive samples were Souq Aljumaa, Souq Alkhamees, Souq Althulatha, and Souq Tajoura. The highest percentage (35.71%) of AIV was recorded in Souq Aljumaa. Positive results for AIV type A were obtained primarily in three species of birds: Ducks (14/65; highest percentage: 21.5%), local chickens (12/98; 12.24%), and geese (2/28; 7.14%). Furthermore, the following three risk factors associated with the spread of AIV type A were identified: Time spent by breeders/vendors at the market (odds ratio [OR] = 11.181; 95% confidence interval [CI] = 3.827–32.669), methods used for disposing dead birds (OR = 2.356; 95% CI = 1.005–5.521), and last visited LBM (OR = 0.740; 95% CI = 0.580–0.944). Restricting the movement of poultry vendors from one market to another may protect against AIV spread. Conclusion: The findings of this study indicate the high risk of AIV spread in LBMs and highlight the need for continuous surveillance of LBMs across the country

Biosecurity and geospatial analysis of mycoplasma infections in poultry farms at Al-Jabal Al-Gharbi region of Libya

Geospatial database of farm locations and biosecurity measures are essential to control disease outbreaks. A study was conducted to establish geospatial database on poultry farms in Al-Jabal Al-Gharbi region of Libya, to evaluate the biosecurity level of each farm and to determine the seroprevalence of mycoplasma and its relation to biosecurity level. A field team of 7 Veterinarians belongs to the National Center of Animal Health was assigned for data recording and collection of blood samples. Personal information of the producers, geographical locations, biosecurity measures and description of the poultry farms were recorded. The total number of poultry farms in Al-Jabal Al-Gharbi Region is 461 farms distributed in 13 cities. Out of these, 102 broiler farms and one broiler breeder farm (10 houses) which were in operation during team visit were included in this study. Following collection of blood, sera were separated and tested by Enzyme-linked immunosorbent assay (ELISA) for the presence of antibodies against Mycoplasma (General antigen for M. gallisepticum and M. synoviae). The seroprevalence of Mycoplasma in the region was 28% (29 poultry farms out of 103 were infected). About 50% (23 out of 47) of poultry farms located in Garian city were infected with Mycoplasma and one significant cluster of Mycoplasma infection in the city was identified. Low level of biosecurity was found in poultry farms of the region. Out of the 103 farms included, 63% of poultry houses has a ground of soil and 44% of them has uncoated walls which may influence the proper cleaning and disinfection. Almost 100% of the farms are at risk of exposure to diseases transmitted by wild birds such as avian influenza and Newcastle disease due to absence of wild birds control program. Although, 81% of the farms have entry restrictions, only 20% have disinfectants at entry which increase the risk of exposure to pathogens. The results of this study highlight the weakness points of biosecurity measures in poultry farms of Al-Jabal Al-Gharbi region and high seroprevalence of mycoplasma. Data collected in this study will assist the Veterinary authorities to apply effective disease control strategies.Keywords: Biosecurity, Geospatial analysis, Mycoplasma, Poultry

Molecular detection and chracterization of infectious bronchitis virus from Libya.

Infectious bronchitis virus (IBV) is a very dynamic and evolving virus, causing major economic losses to the global poultry industry. Recently, the Libyan poultry industry faced severe outbreak of respiratory distress associated with high mortality and dramatic drop in egg production. Tracheal and cloacal swabs were analyzed for several poultry viruses. IBV was detected using SYBR Green I real-time PCR detection based on the nucleocapsid (N) gene. Sequence analysis of the partial N gene indicated high similarity (~ 94%) to IBV strain 3382/06 that was isolated from Taiwan. Even though the IBV strain 3382/06 is more similar to that of the Mass type H120, the isolate has been implicated associated with intertypic recombinant of 3 putative parental IBV strains namely H120, Taiwan strain 1171/92 and China strain CK/CH/LDL/97I. Complete sequencing and antigenicity studies of the Libya IBV strains are currently underway to determine the evolution of the virus and its importance in vaccine induced immunity. In this paper we documented for the first time the presence of possibly variant IBV strain from Libya which required dramatic change in vaccination program

Development of an Optimal Coordination Scheme For Dual Relay Setting In Distribution Network Using Smell Agent Optimization Algorithm

This research work is aimed at developing an optimal coordination scheme for dual relay settings in distribution system. The fault current through a relay in forward direction is usually higher than that in the reverse direction for distribution system. Therefore, it is preferable to have a dual setting directional over-current relay. These relays have the capability to operate in both directions (forward and reverse direction) of fault current with two independent relay settings. Additional fault current contribution to the fault location is present due to the integration of distributed generation to the system. The coordination problem is therefore formulated as a nonlinear optimization problem to help mitigate the operating times of the relays using smell agent optimization (SAO) technique. The developed model was applied on IEEE 14-bus network equipped with synchronous distributed generation. The protection setting comprises of two time dial settings (TDS) and a pick up current setting for each relay. The SAO was used to obtain the TDS with the sole purpose of minimizing it while ensuring that the constraints set were satisfied. In the case of TDS with three cases of faults considered. the results obtained showed that the maximum fault current in all the three cases represent 6.79% while the minimum fault current was reduced to 2.70% when compared with the base case. The developed technique thereby achieved a reduction of time dial settings for which the relay operation of 14.50% and 13.69% reduction for the adopted 14 bus IEEE network

Bladder scan vs urethral cathetarization for measurement of immediate post partum bladder volume

Introduction: Bladder scan is a well known non invasive and cost effective tool for the measurement of post void residual urine(PVR) however with some limitation. Literature on the efficacy of bladder scan on big uterus is limited and not promising. Study Objective: To determine the validity of bladder scan BV13000 in detection of bladder volume in immediate postpartum women. Methodology: A prospective cross sectional study conducted in Hospital Tengku Ampuan Afzan, Pahang from 1st September to 30 November 2010, A total of 193 women who had undergone Caesarean section were recruited on postpartum day 1. Prior to removal of Foley’s catheter, their bladder volumes were first estimated by bladder scan BV13000. Immediately the bladder was then catheterized for the true bladder volume followed by 2D ultrasound bladder scanning to ensure that it was completely emptied. The data was analyzed using SPSS software version 18(SPSS Inc. Chigaco, Illinois). P value of less than 0.05 is considered as statistically significant. Resul : There were a total of 193 women recruited with the mean age of 28.84 years (SD 5.516) with mean BMI of 29.69( SD 5.69) kg/m2 and fundal height of 16cm (SD 2.382 ). The mean for time interval between bladder scan and catheterization was 3 min(range between 1-8 min). There is a linear relationship between the bladder scan-estimated and catheter bladder volumes (r2=082). The patient’s body weight also is significantly (p=0.01) correlated with the bladder scan-estimated volume with r2 of-0.25. The size of the uterus however does not correlate with the bladder-scan volume Conclusion : Bladder scan is comparable to urethral catheterization in the measurement of postpartum bladder volume