Doubly-Fed Induction Machine for use in Mini-Hydro Power Plants - Technical Assessment

Hydropower is the most popular and fastest growing renewable energy technology among all. Environmental and ecological concerns involved with large water reservoirs limited the usage of potentially available sites. Thus, the present trend is growing towards building small hydro power plants as the hydro power is clean and economical source for power generation. Different site parameters (head, flow) varies throughout the year which affects the power production capability of hydropower system and makes the production inefficient, in addition, some of the sites cannot be exploited fully just because of being less economical due to these parameter variations. Variable speed operation improves the efficiency of hydro power generation system by running the system at a speed so that the optimum efficiency can be achieved at different operating points. Various configurations are available for variable speed operation and Doubly Fed Induction Generator (DFIG) is also a popular configuration in wind energy systems. This work is a study to check the performance of DFIG in mini-hydropower system. Firstly, a brief look is taken on steady state model of DFIG which is required to understand the machine characteristics then dynamic model equations for DFIG, grid circuit and DC link are derived which is required for simulation of the system then DFIG model is validated. Optimum efficiency speed module is developed to obtain the speed reference for control system based on power demand for optimum efficiency operation. Finally, control system for DFIG is developed based on vector control. Performance of the developed model is checked by carrying out simulation at different operating conditions. The power generation capacity is affected by variation in site conditions such as water head. Therefore, the model is simulated at different water heads with different power demands. Further the super-synchronous and sub-synchronous operation of DFIG is checked based on speed reference generated by optimum efficiency speed module. Also efficiency for both variable and fixed speed operation is plotted and it is observed that the efficiency is higher at variable speed operation compared to fixed speed operation for same power demand

Optical, microstructural and electrical studies on sol gel derived TiO2 thin films

TiO2 thin films have many interesting optical, physical, electrical and chemical properties that offer many applications in different fields of science and technology. The sol-gel spin coating technique has immense advantageous; such as low cost, usage of very simple equipment and relatively easy process control method. The optical, structural, microstructural and electrical properties have been analyzed through four point probe, XRD, SEM, high resolution electron microscopy, AFM and UV-VIS-NIR spectrophotometer. This paper is a research article about the sol-gel spin coated TiO2 thin film. The results will focus on the preparation and coating of TiO2 thin films on glass substrate at different annealing temperatures

Frequency of depression and anxiety among patients with chronic spontaneous urticaria visiting a tertiary care hospital in Karachi, Pakistan

Objective: To determine the frequency of anxiety and depression among chronic spontaneous urticarial patients presenting at a tertiary care hospital.Methods: The prospective, cross-sectional study was conducted at the Aga Khan University Hospital, Karachi, from February to August 2015, and comprised patients diagnosed with chronic spontaneous urticaria at the dermatology clinic. All the participants were assessed for anxiety and depression using Aga Khan University-Anxiety Depression Scale. Data was collected in face-to-face interview using a structured questionnaire. The association of the condition with different characteristics were calculated after stratification for age, gender, occupation and monthly income. SPSS 19 was used for data analysis..Results: Of the 146 study participants, 84(57.5%) were males and 62(42.5%) were females. The overall mean age was 39±15.6 years. Of the total, 39(26.7%) had depression and anxiety. Depression and anxiety were more frequent among patients with a positive family history of mental disorders (p=0.02).Conclusion: Anxiety and depression were found to be considerably common among chronic spontaneous urticaria patients, with patients having a positive family history for mental illnesses particularly vulnerable

Birth Asphyxia - Clinical Experience and Immediate Outcomes

To find out immediate outcome ofneonates with birth asphyxia and its associationwith risk factors.Methods: This cross sectional study included allconsecutive babies admitted with diagnosis of birthasphyxia . Babies with congenital heart disease,congenital malformations and prematurity wereexcluded. Biodata and clinical parameters includingplace of delivery,dai handling,time of arrival inhospital,mode of delivery, grades of hypoxicischemic encephalopathy, outcome in terms ofdischarge and death were recorded.Results: Sixty one patients were included in thestudy. Majority (80.3%) were male..Mothers havingregular antenatal checkup were 65.5%. Eleven (18%)babies were home delivered and 50(82%) in hospitalsetup. In 16.4% babies there was history of daihandling. 60.7% babies were delivered by SVD and39.3 % by C- section. Majority (83.6 %) presentedwithin 6 hours. Hypoxic ischemic encephalopathystage I, II and III was seen in 39.3%, 49% and11.5%respectively. Forty eight (78.7%) babies weredischarged and 13(21.3%) died. No evidence ofassociation was found between outcome at dischargeand time of arrival at hospital (p value=0.33)and daihandling (p value= 0.114). Significant associationwas found between outcome at discharge and placeof delivery (p value=0 .031) and outcome at dischargeand hypoxic ischemic encephalopathy stage (pvalue=0.000).Conclusion: Asphyxiated newborns havesignificant short term mortality in association withhome deliveries and hypoxic ischemicencephalopathy stage II

Exploring key physiological attributes of grapevine cultivars under the influence of seasonal environmental variability

Seasonal climatic variability is a key challenge in many grape-growing regions across the globe, affecting phenology, growth, physiological responses, and yield at harvest. Unfavourable climatic conditions impair the plant's physiological processes, such as chlorophyll accumulation, gas exchange and photosynthesis in grapevine leaves. It is critical to unlock the complex physiological behaviour of grapevine cultivars at key phenological stages and under varying environmental conditions. The present study was designed to evaluate the key physiological processes, such as gas exchange, chlorophyll contents and water use efficiency (WUE), of four table grape cultivars at key growth stages under varying environmental conditions of the Pothwar region, in a factorial experimental set up (Location× Year × Cultivar × Phenological stage). The physiological responses of the table grape cultivars were recorded at the 5-leaf stage, full bloom, berry set, veraison and harvest during two consecutive vintages (2019 and 2020) in two locations (Islamabad and Chakwal). The results show that the mean photosynthetic activity in colder Islamabad was 30.7 % higher than in Chakwal, and the transpiration rate and WUE were 10.4 % and 28.6 % higher. Similarly, 12 % higher photosynthetic activity, with 13 % more WUE, was observed in the colder vintage of 2020 compared to that of 2019. The vine physiological activity also varied among cultivars; for example, cv. Sugraone was found to have 12 % more chlorophyll and 30 % higher photosynthetic activity than cv. Kings Ruby. Similarly, higher photosynthetic activity and transpiration rates were recorded at the berry set stage, while WUE peaked near blooming. The biplot analysis for the first two principal components also showed cv. Sugraone to be a highly responsive and physiologically efficient cultivar. The findings of the present research will help to better assess the effect of seasonal variability on vine physiological performance and to identify genotypes with higher photosynthetic potential and WUE. It could also assist in devising vineyard management strategies to better adapt to varying environmental conditions

An annotated list of planthoppers with alternate hosts from Kallar tract of Punjab, Pakistan

Diversity of planthoppers and their host plants were studied in the "Kallar" tract of the Punjab, Pakistan (an important growing area of the world for producing Basmati rice). Planthoppers are considered the most important pests of rice. Delphacidae and Cixiidae are families of planthoppers with the most harmful species. Delphacids are primarily vector of the viruses, whereas Cixiids are vectors of phytoplasmas, mycoplasmas and prokaryotes-like associated to the class Mollicutes. Specimens of planthoppers were collected from the rice fields and surrounding weeds. A list of Fulgoromorpha is provided, with distributional and biological records as well. Records are extracted primarily from field data and specialized reference sources. Seven species from two different families of Fulgoromorpha were related to rice ecosystem (Cixiidae, one species and Delphacidae; six species). Three Delphacid species, whitebacked planthopper Sogatella furcifera, brown planthopper Nilaparvata lugens and small brown planthopper (SBPH) Laodelphax striatellus are well-known vectors of severe rice pathogenic diseases in the Oriental and Paleartic regions. Laodelphax striatellus was recorded on rice for the first time in Pakistan. Among alternate hosts, Trifolium alexandrium, Leptochloa chinensis, Helianrhus allus, Medicago polymorpha and Sorghum bicolor were recorded for L. striatellus, while Leptochloa chinensis, Helianrhus allus, Medicago polymorpha, Sorghum bicolor, Zea mays and Cynodon dactylon were recorded for S. furcifera for the first time. N. lugens was recorded on weeds Leptochloa chinensis and Medicago polymorpha.Fil: Rizwan, Muhammad. Rice Research Institute; PakistánFil: Atta, Bilal. Rice Research Institute; PakistánFil: Marino, Ana Maria. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Entomología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Mariani, Roxana. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Entomología; ArgentinaFil: Sabir, Arshed Makhdoom. Rice Research Institute; PakistánFil: Tahir, Muhammad. The Islamia University of Bahawalpur; PakistánFil: Rizwan, Misbah. Government College for Women; PakistánFil: Sabar, Muhammad. Rice Research Institute; PakistánFil: Rafique, Ch. Muhammad. Rice Research Institute; PakistánFil: Afzal, Muhammad. Hill Fruit Research Station; Pakistá

Characterization of cowpea to harvest rainwater for wheat in semiarid conditions

Aim of study: A field experiment was executed, under rainfed conditions from 2014-15 to 2017-18, to study the role of cowpea (Vigna unguiculata L.) in rainwater harvesting to enhance the wheat (Triticum aestivum L.) yield.Area of study: Rain-fed area of Pothwar region, Punjab, Pakistan.Material and methods: We designed three treatments (T1: control; T2: cowpea grown after conventional tillage and incorporated into soil to act as “green manure”; and T3: grown without any tillage practice, cut with sickle and spread as “mulch”). The effect of these treatments on soil moisture conservation was studied against conventional farmer’s practice, wherein no host crop is grown before wheat sowing.Main results: Available soil water remained highest in T2 during first three years when sufficient rainfall was received contrary to fourth year with low rainfall. The results revealed that cowpea biomass of 15.2 t/ha and 13.72 t/ha, from T2 and T3 respectively, were produced during 2015 corresponding to 213 mm rainfall. Whereas, these quantities increased to 25.69 t/ha and 24.29 t/ha during 2017 with 387 mm of rainfall. The study revealed that net income from wheat crop under T2 was Rs 13000 and Rs 9000 per hectare higher than that of control during the first two years respectively. Contrarily, net income from T2 was found negative and benefit-cost ratio reduced to 0.79 when very low rainfall was received during the last year.Research highlights: Use of cowpea as green manure gave maximum net return if sufficient rainfall is received during decomposition of cowpea and hence recommended for in-situ rainwater harvesting

Regeneration of Plantlets from various Explants of Tetraploid watermelon

Micropropagation of tetraploid watermelon is important to cope with high cost of seed. Seeds of tetraploid watermelon were grown in vitro to raise seedlings. Hypocotyl and cotyledonary explants and media supplemented with plant growth regulators (BAP and NAA) was explored for callus induction and organogenesis. Data was collected for callus, shoot and root induction. Maximum callus induction was observed at BAP 5 mgL-1 (76.66%) from cotyledon and (73.33%) from hypocotyls explant. The callus induced from different explants was sub-cultured on the shoot regeneration medium. Higher shoot induction (96.66%) was observed  from cotyledon and hypocotyl explant (76.66%) on MS + 1.0 mgL-1 BAP + 0.2 mgL-1 NAA with maximum number (6.3) of shoot per explant and average shoot length 4.5 cm. Among different types (NAA and IAA) and concentrations (0, 0.1, 0.3, 0.7, 1.0 mgL-1) of auxins investigated for root induction, maximum frequency of rooting was observed in 0.1 mgL-1 NAA while no root formation was observed at higher levels of auxin (1.0 mgL-1). Similarly in case of number of roots per shoot maximum root (4.3) was obtained on MS medium supplemented with 0.1 mgL-1 NAA. Key Words: Regeneration, Explant, Tetraploid, Water Mello

Babesia bovis in Large Ruminants in Pakistan - Molecular Detection and Haemato-Biochemical Alterations

Background: Babesiosis is endemic in Pakistan and is one of the most important bovine diseases that causes huge economic losses and high mortality in young animals. A hematobiochemical study was conducted to unveil the difference between diseased and healthy animals in selected districts i.e., Faisalabad (31° 25' 7.3740'' N and 73° 4' 44.7924'' E), Toba Tek Singh (30° 58' 9.7392'' N and 72° 27' 40.7484'' E) and Jhang (31° 16' 40.9656'' N and 72° 18' 42.3360'' E) of Punjab, Pakistan. Materials, Methods & Results: A total of 518 (Cattle = 360, Buffalo = 158) blood samples were collected. The samples were analyzed by polymerase chain reaction (PCR) targeting apocytochrome b-gene (Babesia bovis-gene) (CYTb) followed by haemato-biochemical analysis. Chi-square test for univariate analysis was used to analyze the data. In summer the PCR-based prevalence was 29.4 (53/180) and 24.05% (19/79) in cows and buffaloes, respectively. On the other hand, in winter results showed that 12.7 (23/180), 13.92 % (11/79) samples positive for Babesia genus from cows and buffaloes, respectively. The positive samples were further investigated for hematological and biochemical analysis. The results revealed that, the mean value of hematological parameters like RBCs, Hb, PCV, MCV and MCHC was significantly (P < 0.05) decreased in infected animals (cows and buffaloes) as compared to the non-infected ones. While the biochemical parameters like Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), cholesterol and Lactate dehydrogenase were significantly (P < 0.05) increased in infected animals as compared to healthy animals. This study is the first molecular and hematobiochemical evidence of Babesia bovis in dairy herds of Punjab province, Pakistan. Discussion: Bovine babesiosis is one of the important tick-borne diseases (TBD) affecting dairy industry. In bovines, among 3 Babesia species that cause the disease B. bovis is more pathogenic with high mortality and morbidity. Pakistan is situated in tropical and sub-tropical region where the humidity is high in some part of countries. This high humidity mostly favors the reproduction of the ticks thus higher prevalence of TBDs in this region. Initially the babesiosis was diagnosed by light microscopy using thin blood smear stained with Giemsa stain. Many studies verified that PCR is a more specific and sensitive tool than conventional techniques for the detection of carrier / asymptomatic ruminants. The haemato-biochemical profile is another valuable footprint to track the disease. Keeping in view the above-mentioned fact the present project has been planned to evaluate the haemato-biochemical alteration between health and Babesia infected cattle along with the molecular detection of Babesia species involved in bovine babesiosis. The mean values of haemato-biochemical parameters in clinically ill and healthy animals revealed that the mean values of hematological parameters like RBCs, Hb, PCV, and HCT were significantly decreased in diseased animals as compared to the healthy ones. All these might be due the fact that the parasite is intra-erythrocytic in nature and destruction of red blood cells results in significant (P < 0.05) decrease level of all the hematological parameters. The mean value of ALT in babesiosis infected cattle was significantly higher as compared to healthy cattle. The mean values of AST and LDH in babesiosis infected cows was significantly higher as compared to that in healthy cows. The elevation in liver enzymes in babesiosis may be due to the hepatic damage and lesions induced by the parasite during its multiplication in the blood followed by disturbed liver function. These enzymes are present in high concentrations in the muscles and liver. High level of these enzymes in the blood is indicator of organ necrosis or damage. Keywords: bovines, buffaloes, tick-borne diseases, babesiosis, liver enzymes, PCR