Small signal modeling and analysis of microgrid systems

This dissertation focuses on small-signal modeling and analysis of inverter based microgrid systems. The proposed microgrid consists of two microsources placed on two different buses. The buses are connected using a distribution feeder with some impedance. The proposed microgrid can operate with the grid support, or without the grid support. When operated without the grid support, the standalone system’s microsources participate in controlling the system voltage and frequency. For a non-inertia source, such as the inverter, the load perturbations play an important role in system dynamics. In paper-I, such complex system was studied. In the grid-tied mode, the microsources share the load demand with other sources that are present in the main grid. The control algorithm for such system is much simpler than that of the islanded system. However, when aggregated in multi-bus system, prohibitively higher order state-space models are formed. In paper-II, a reduced order modeling of such systems was considered. Singular perturbation method was applied to identify the two time-scale property of the system. In paper-III, a similar approach was taken to develop a reduced order model of the islanded system that was developed in paper-I. Application of such reduced order models were illustrated by using them to simulate a modified IEEE-37 bus microgrid system. The islanded microgrids system’s stability is characterized in paper-IV by the Markov Jump Linear System Analysis. Conservative bounds on the expected value of the state were determined from a combination of the Markov process parameters, the dynamics of each linear system, and the magnitude of the impulses. The conclusions were verified with the simulation results. --Abstract, page iii

Modeling, Analysis, and Control Design of a Single-Stage Boost Inverter

A single-phase, single-stage, differential boost inverter comprises two independently-controlled boost DC-DC converters, with the load connected between their outputs. The net voltage on the load is sinusoidal and has a controllable frequency and magnitude that is larger than that of the DC source. The present work first derives steady-state and small-signal models of the inverter with parasitic elements. The results obtained from the line-to-output transfer function, control-to-output transfer function, open-loop input impedance, and open-loop output impedance models are compared with that of the ones obtained from the experimental testbed. Using the new models, a voltage mode controller is designed in the synchronous reference frame. The regulator design is explored through the use of an example. The results are verified against the small-signal model, then PLECS simulations, and finally a laboratory experiment. The results indicate excellent agreement between the model and experiment during transients in voltage reference, input source voltage, and output load. A sensitivity analysis is performed based on the inverter model considering the parameter variation. Finally, loss and efficiency estimations are provided in this work

Isolation of bacterial fish pathogen Aeromonas hydrophila and therapeutic effects of medicinal plants on its invasion

Aeromonas hydrophila, a bacterial pathogen,  was isolated form Pangasius hypophthalmus. For pathogenicity test, different doses were injected intramuscularly in Barbonymus gonionotus. Crude extracts were prepared from various parts Azadirachta indica, Curcuma longa, C. zedoaria, and Callotropis gigentia and applied to B. gonionotus for 7 days. Bath treatment was done up to their tolerance level and well ventilation was confirmed for aeration and 50% water was exchanged daily. Minimum inhibitory dose was detected as 7 mg/ml. High inhibitory effect was observed in case of A. indica and mixed extract of A. indica and C. gigentia. Both A. indica and C. gigentia showed the best result with 90-95% recovery of infected fish at a dose of 7 mg/l. C. zedoaria showed moderate to weak effect with 50-60% recovery at the same dose. The present study showed that medicinal plants would be an effective control measure against A. hydrophila

Small-Scale Turkey Farming in Bangladesh: Farming Practices, Profitability and Supply Chain Mapping

The study was conducted to know the existing turkey production system, supply chain mapping, and identifying the prospects and problems of turkey rearing in some selected areas of Bangladesh during October 2019 to December 2019. A total of 100 turkey raisers were surveyed following convenience method of sampling technique. The primary data were collected, analyzed accordingly and tabular presentation method was applied with the help of simple descriptive statistical measures e.g. frequency distributions, percentage, sum and means to illustrating the results. Profitability analysis was done on the basis of variable cost, fixed cost, return by using arithmetic means and percentages. The study revealed that 87 male and 13 female respondents were surveyed, of them cent percent found educated. About 56% turkey keeper’s main occupation was business, 27% service and 12% in farming while 88.57% involved with farming as secondary sources of income. Average landholding for homestead, cultivable and non-cultivable was 24.40, 129.71 and 29.47 decimal, respectively. About 59% farms started for commercial purpose, 32% for non-commercial purpose and 9% for both. About 60% respondents kept less than 50 turkeys and only 2% kept 501-1000 turkeys. Among the surveyed farms55% stopped their operation and 45% farms found running their business. Among the running farms cent percent were small-scale group. The average feed intake was 192.13 grams per day per bird at 20 weeks of age. Turkey laid on an average 139 eggs a year irrespective of variety and for hatching poults, the fertility and hatchability rate found between 65 to 100% and 50 to 90%, respectively. About 28% farmers experienced the deaths of turkey because of Cold, Pox, Ranikhet, Bird flu and unknown cases and 69.47% farmers took veterinary advice from Upazila Livestock Hospital and rest from other sources. Farmers to consumers were the most common and widely used marketing channel for egg, chick and adult turkey. The market intermediaries of turkey farm carried out different marketing functions e.g. buying and selling, pricing, transportation, sorting, distribution and market information. The average net return and benefit-cost ratio was BDT 127838.04 and 1.38, respectively for 50 turkeys per year. In the study, turkey rearing found some comparative benefit over chicken and ducks e.g. higher weight gain, forage eater, lower diseases rate and suitability for the country. The main problem of turkey rearing identified as market instability, lack of quality turkey feed, higher feed price, lack of proper marketing facility and training on turkey farming. In conclusion, the small-scale turkey farming could be a viable source of income for the rural people of Bangladesh after taking some remedial steps by the Government of Bangladesh for the aforesaid hindrances faced by the turkey farmers

Biochemical and structural investigations clarify the substrate selectivity of the 2-oxoglutarate oxygenase JMJD6.

JmjC domain-containing protein 6 (JMJD6) is a 2-oxoglutarate (2OG)-dependent oxygenase linked to various cellular processes, including splicing regulation, histone modification, transcriptional pause release, hypoxia sensing, and cancer. JMJD6 is reported to catalyze hydroxylation of lysine residue(s) of histones, the tumor-suppressor protein p53, and splicing regulatory proteins, including u2 small nuclear ribonucleoprotein auxiliary factor 65-kDa subunit (U2AF65). JMJD6 is also reported to catalyze N-demethylation of N-methylated (both mono- and di-methylated) arginine residues of histones and other proteins, including HSP70 (heat-shock protein 70), estrogen receptor α, and RNA helicase A. Here, we report MS- and NMR-based kinetic assays employing purified JMJD6 and multiple substrate fragment sequences, the results of which support the assignment of purified JMJD6 as a lysyl hydroxylase. By contrast, we did not observe N-methyl arginyl N-demethylation with purified JMJD6. Biophysical analyses, including crystallographic analyses of JMJD6Δ344-403 in complex with iron and 2OG, supported its assignment as a lysyl hydroxylase rather than an N-methyl arginyl-demethylase. The screening results supported some, but not all, of the assigned JMJD6 substrates and identified other potential JMJD6 substrates. We envision these results will be useful in cellular and biological work on the substrates and functions of JMJD6 and in the development of selective inhibitors of human 2OG oxygenases.Commonwealth Scholarship Commission, U

Therapeutic performances of some selected aqua drugs

This study was carried out at the Disease Laboratory of the Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh, Bangladesh to verify the therapeutic performances of six commercial aqua drugs; three doses were selected as less than recommended, recommended and more than recommended to assess their performances. Before starting therapeutic experimental nine climbing perch (Anabas testudineus) and six stinging catfish (Heteropneustes fossilis) were confirmed as diseased ones by their clinical signs. The backswimmers (Notonecta glauca) were collected from faculty of fisheries pond and fish louses (Argulus sp.) were collected from tilapia fishes. Effective doses and their performances were determined on the basis of desired water quality change and clinical signs. It was found that all the drugs performed better at more than recommended doses as follows Aqua Ox performed better at the rate of 0.2 mg/l, GR Plus, 0.0005 ml/l, ID Plus (5%), 0.00026 ml/l; Active Blue, 0.0002 ml/l; Hashpoka Killer, 0.0001 ml/l; and Para Control, 0.001 ml/l. So these doses were suggested as recommended doses

Therapeutic performances of some selected aqua drugs

This study was carried out at the Disease Laboratory of the Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh, Bangladesh to verify the therapeutic performances of six commercial aqua drugs; three doses were selected as less than recommended, recommended and more than recommended to assess their performances. Before starting therapeutic experimental nine climbing perch (Anabas testudineus) and six stinging catfish (Heteropneustes fossilis) were confirmed as diseased ones by their clinical signs. The backswimmers (Notonecta glauca) were collected from faculty of fisheries pond and fish louses (Argulus sp.) were collected from tilapia fishes. Effective doses and their performances were determined on the basis of desired water quality change and clinical signs. It was found that all the drugs performed better at more than recommended doses as follows Aqua Ox performed better at the rate of 0.2 mg/l, GR Plus, 0.0005 ml/l, ID Plus (5%), 0.00026 ml/l; Active Blue, 0.0002 ml/l; Hashpoka Killer, 0.0001 ml/l; and Para Control, 0.001 ml/l. So these doses were suggested as recommended doses

JMJD5 is a human arginyl C-3 hydroxylase.

Oxygenase-catalysed post-translational modifications of basic protein residues, including lysyl hydroxylations and Nε-methyl lysyl demethylations, have important cellular roles. Jumonji-C (JmjC) domain-containing protein 5 (JMJD5), which genetic studies reveal is essential in animal development, is reported as a histone Nε-methyl lysine demethylase (KDM). Here we report how extensive screening with peptides based on JMJD5 interacting proteins led to the finding that JMJD5 catalyses stereoselective C-3 hydroxylation of arginine residues in sequences from human regulator of chromosome condensation domain-containing protein 1 (RCCD1) and ribosomal protein S6 (RPS6). High-resolution crystallographic analyses reveal overall fold, active site and substrate binding/product release features supporting the assignment of JMJD5 as an arginine hydroxylase rather than a KDM. The results will be useful in the development of selective oxygenase inhibitors for the treatment of cancer and genetic diseases

第861回 千葉医学会例会・第1内科教室同門会例会 7.

This article was published in the PLoS ONE [© 2016 Rahman et al.] and the definitive version is available at: http://doi.org/10.1371/journal.pone.0161647 The Journal's website is at: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0161647Objectives We evaluated the impact of the Improving Maternal, Neonatal, and Child Survival (IMNCS) project, which is being implemented by BRAC in rural communities in Bangladesh. Methods Four districts received program intervention i.e. trained community health workers to deliver essential maternal, neonatal, and child healthcare and nutrition services while two districts were treated as comparison group. A quasi-experimental study design (compared beforeand-after) was undertaken. Baseline survey was conducted in 2008 among 7200 women followed by end line in 2012 among 4800 women with similar characteristics in the same villages. We evaluated maternal antenatal and post natal checkup, birth plans and delivery, complication and referred cases during antenatal checkup and post natal period, and child health indicators such as birth asphyxia, neonatal sepsis, and its management by the medically trained provider. Findings Increased number (four or more) antenatal visits, skill-birth attended delivery and postnatal visits (three or more) in the intervention group preceding four-year intervention period were observed compare to their counterpart. We noted negative difference-in-difference estimator (-5.0%, P = 0.159) regarding to the all major birth plans i.e. delivery place, birth attendant, and saved money in the comparison areas. Significant reduction of ante-partum and intra-partum complications occurred in the intervention group, contrary complications of such event increased in the comparison areas (-6.3%, P<0.05 and-20.5%, P<0.001 respectively). Referral case to the health centers due to these complications boosted significantly in intervention group than comparison group (2.3%, P<0.01 and 6.6%, P<0.001 respectively). Mother's knowledge of breastfeeding initiation and the practice of initiating breastfeeding within an hour of birth amplified significantly (14.6%, P<0.001 and 8.3%, P<0.001 respectively). We did not find any significant difference regards to the management of low birth weight by the medically trained health care provider and complete vaccination between the intervention and comparison arm. Conclusion Medically trained health care provider assisted community based public health intervention could increase number of antenatal and postnatal visit, thereby could decrease pregnancy associated complications. These interventions may be considered for further up scaling when resources are limited.Publishe

Evaluation in Mice of a Conjugate Vaccine for Cholera Made from Vibrio cholerae O1 (Ogawa) O-Specific Polysaccharide

Background: Protective immunity against cholera is serogroup specific. Serogroup specificity in Vibrio cholerae is determined by the O-specific polysaccharide (OSP) of lipopolysaccharide (LPS). Generally, polysaccharides are poorly immunogenic, especially in young children. Methodology Here we report the evaluation in mice of a conjugate vaccine for cholera (OSP:TThc) made from V. cholerae O1 Ogawa O-Specific Polysaccharide–core (OSP) and recombinant tetanus toxoid heavy chain fragment (TThc). We immunized mice intramuscularly on days 0, 21, and 42 with OSP:TThc or OSP only, with or without dmLT, a non-toxigenic immunoadjuvant derived from heat labile toxin of Escherichia coli. Principal Findings We detected significant serum IgG antibody responses targeting OSP following a single immunization in mice receiving OSP:TThc with or without adjuvant. Anti-LPS IgG responses were detected following a second immunization in these cohorts. No anti-OSP or anti-LPS IgG responses were detected at any time in animals receiving un-conjugated OSP with or without immunoadjuvant, and in animals receiving immunoadjuvant alone. Responses were highest following immunization with adjuvant. Serum anti-OSP IgM responses were detected in mice receiving OSP:TThc with or without immunoadjuvant, and in mice receiving unconjugated OSP. Serum anti-LPS IgM and vibriocidal responses were detected in all vaccine cohorts except in mice receiving immunoadjuvant alone. No significant IgA anti-OSP or anti-LPS responses developed in any group. Administration of OSP:TThc and adjuvant also induced memory B cell responses targeting OSP and resulted in 95% protective efficacy in a mouse lethality cholera challenge model. Conclusion: We describe a protectively immunogenic cholera conjugate in mice. Development of a cholera conjugate vaccine could assist in inducing long-term protective immunity, especially in young children who respond poorly to polysaccharide antigens