724 research outputs found
Exploring the possibility of enhancing the figure-of-merit ( 2) of NaCoO: A combined experimental and theoretical study
Search of new thermoelectric (TE) materials with high
\textit{figure-of-merit} (ZT) is always inspired the researcher in TE field.
Here, we present a combined experimental and theoretical study of TE properties
of NaCoO compound in high-temperature region. The experimental
Seebeck coefficient (S) is found to vary from 64 to 118 V/K in the
temperature range K. The positive values of S are indicating the
dominating p-type behaviour of the compound. The observed value of thermal
conductivity () is 2.2 W/m-K at 300 K. In the temperature region
K, the value of increases up to 2.6 W/m-K and then
decreases slowly till 620 K with the corresponding value of 2.4 W/m-K.
We have also carried out the theoretical calculations and the best matching
between experimental and calculated values of transport properties are observed
in spin-polarized calculation within DFT+\textit{U} by chosen \textit{U} = 4
eV. The maximum calculated value of ZT is found to be 0.67 at 1200 K for
p-type conduction. Our computational study suggests that the possibility of
n-type behaviour of the compound which can lead to a large value of ZT at
higher temperature region. Electron doping of 5.110
cm is expected to give rise the high ZT value of 2.7 at 1200 K.
Using these temperature-dependent ZT values, we have calculated the maximum
possible values of efficiency () of thermoelectric generator (TEG) made
by p and n-type NaCoO. The present study suggests that one can
get the efficiency of a TE cell as high as 11 when the cold and hot
end temperature are fixed at 300 K and 1200 K, respectively. Such high values
of ZT and efficiency suggest that NaCoO can be used as a
potential candidate for high-temperature TE applications
Spider Monkey Optimization Based Optimal Sizing of Battery Energy Storage for Micro-Grid
The ever-increasing need for power in today\u27s environment calls for a secure and effective energy supply network. Distributed renewable options such as Diesel Generator (DG), wind turbine (WT) and photovoltaic (PV) solar energy may be integrated inside a micro grid (MG) to supply electricity to customers in a sensible manner. In order to provide a more efficient and affordable source of electricity, the battery storage device is built into the micro grid. This article identifies the cost-based approach to calculate the optimum size of the Battery energy storage (BES) for MG operations. Some constraints, i.e., the power output of the Distributed Generators (DGs), the power and energy capacity of BES, the charging/discharge performance of BES, the working reserve and the fulfilment of the load requirement, should also be considered. In this article the Spider Monkey (SM) algorithm is a modern evolutionary technology that is used to build correction policies and to execute less costly dispatch. Four different cases have been studied. The results are compared with recently developed Fire Fly (FF) algorithm to corroborate the effectiveness of the proposed algorithm. The results show that the proposed algorithm has low power loss and the operating cost of the proposed SM technique is 0.0129% less than existing FF algorithm based micro-grid system. Here, IEEE 33 bus system performed to prove the effectiveness of the proposed SM algorithm over the FF algorithm
Numerical Simulations of Oscillating Soliton Stars: Excited States in Spherical Symmetry and Ground State Evolutions in 3D
Excited state soliton stars are studied numerically for the first time. The
stability of spherically symmetric S-branch excited state oscillatons under
radial perturbations is investigated using a 1D code. We find that these stars
are inherently unstable either migrating to the ground state or collapsing to
black holes. Higher excited state configurations are observed to cascade
through intermediate excited states during their migration to the ground state.
This is similar to excited state boson stars. Ground state oscillatons are then
studied in full 3D numerical relativity. Finding the appropriate gauge
condition for the dynamic oscillatons is much more challenging than in the case
of boson stars. Different slicing conditions are explored, and a customized
gauge condition that approximates polar slicing in spherical symmetry is
implemented. Comparisons with 1D results and convergence tests are performed.
The behavior of these stars under small axisymmetric perturbations is studied
and gravitational waveforms are extracted. We find that the gravitational waves
damp out on a short timescale, enabling us to obtain the complete waveform.
This work is a starting point for the evolution of real scalar field systems
with arbitrary symmetries.Comment: 12 pages, 11 figures, typos corrected, includes referee input,
references corrected, published versio
Conquering maternal mortality: skill development in medical curriculum
Background: Maternal Mortality Rate remains to be high in developing countries despite the advances made in the modern world. A medical student needs to understand the basic clinical subjects and in a short span of one year translate it into patient care. A skill development method was initiated in the final year curriculum of medical students to integrate the basic knowledge of labor with the final outcome of reducing maternal mortality rate.Methods: The skills were demonstrated on mannequins and simulation models of difficult situations in labour were provided. The study was conducted in Saveetha Medical College in the Department of Obstetrics and Gynaecology in May 2015 as a one day hands on workshop for medical undergraduate students. One hundred and fourteen medical students conducted normal labor, applied forceps and ventouse, sutured episiotomies and perineal tear and performed a drill on active management of third stage of labor on training mannequins. All the basic didactic teaching and its translation into clinical skills were tested pertaining to the problem of parturition. Plenary discussion of each demonstrable skill was done by a galaxy of experts. This was followed with Mind Mapping of concepts developed. Pretest and posttest helped the teaching faculty to assess the impact of knowledge generated. Feedback was obtained to improvise the existing teaching method and develop new teaching tools.Results: The students were able to comprehend Conduct of Labor from its basics and decide on the relevant clinical implications. The case based skill demonstrations done on instrumental delivery, episiotomy suturing, clinical pelvimetry, active management of third stage of labor and monitoring of labor using partogram gave students hands on experience and improved their practical knowledge.Conclusion: Skill Development in conduct of labour helps medical students to understand the clinical implications better. A well trained medical student can thus help to reduce maternal mortality rate in developing countries
Cross sectional study on analysis of reasons for refusal of PPIUCD at GIMS, Gadag
Background: Women are highly motivated and receptive to accept Family Planning (FP) methods during the postpartum period. Intrauterine Contraceptive Device (IUCD) is one of the commonly used reversible methods of contraception and provide very effective, safe and long-term protection against pregnancy and the health risks associated with the method are negligible. Taking advantage of the immediate postpartum period for counselling on family planning and IUCD insertion, overcomes multiple barriers to service provision. The increased institutional deliveries are opportunity to provide women easy access to immediate PPIUCD services. Objective-The aim of the study was to determine proportion of women accepting postplacental intrauterine contraceptive device insertion, and to describe the factors associated with acceptability and non-acceptance.Methods: Cross-sectional study conducted from September 2021 to October 2021 in 250 women admitted for delivery at Gadag institute of medical sciences, Gadag. The respondents were interviewed using structured interviewer administered questionnaire.Results: In the study, it is found that overall awareness regarding PPIUCD in the study population is only 32% which is comparable with the study findings of Rajasthan where the 8 awareness was 20.2%. The readiness rate for PPIUCD insertion after the counselling in present study was 8% which is similar the study report from Government Medical College, Trissur, Kerala where the acceptance rate 1 was 10.5%. The major factors associated with nonacceptance were refusal by patient (50%) and relatives.Conclusions: The emerging factors for less acceptance of PPIUCD are low literacy rate among women and infrequent counselling and education during antenatal period. Integration of a PPIUCD counselling service at every delivery point with provision of couple counselling can improve the success of this programme
Pap smear in antepartum women: an opportunity to screen and create awareness
Background: Cervical and breast cancers are the leading malignancies in females in India. Cancer cervix is preventable and treatable if detected at premalignant stage. Pap smear is a recommended screening method for cancer cervix and its precursors. Pap smear screening in antenatal period presents an opportunity to screen for premalignant cervical lesions and genital infections. This study was undertaken to determine the prevalence of abnormal cervical smears and genital infections among antenatal women.Methods: It is a prospective study in which, 200 antenatal mothers at booking visit, were included in the study. Details on their demographic characteristics, obstetric profile, and past history of Pap test were collected. Liquid based cytology was used for the test. The cytological results were reported based on the Bethesda classification system 2001.Results: Among 200 antenatal women 57% were between 21-25 yrs of age and 18% were less than 20 years. 38% of women were less than 20 years of age at the time of beginning of sexual activity. 56% were primi gravida and others were multi gravida. 95.5 % of women were literate. 89% of women were unaware of Pap smear test. Among the 200 Pap smear reports, 23% were normal, 55.5% nonspecific inflammatory changes, 8.5% Candida infection and 13% bacterial vaginosis. None were reported with premalignant changes.Conclusions: In a population where people do not undergo Pap test due to varied reasons, antenatal Pap test not only provides an excellent opportunity to screen and create awareness for further screening, also helps detect genital infections
Screening of cancer cervix: Pap smear in rural India
Background: The incidence of cervical premalignant lesions in rural India is likely to be high due to presence of several risk factors like early marriage, early coitarche and multiparity. Hence prospective cross sectional study was conducted to find the incidence of pre-invasive state and cancer of cervix in women between the age group 30 and 60 years, visiting Thirumazhisai health centre by Pap’s smear method.Methods: Cervical mucosa is scraped, using Ayre spatula a 360° turn is made at the transition zone and smeared on a slide and papanicolaou stain is applied and the slide is examined under microscope. If Pap’s smear confirms low/high grade lesion, biospy is done to confirm the finding. The result is analysed for pre-invasive state.Results: Out of the cases (107) examined with in the study period, 36.45% were normal. Out of the rest 47.05% had an inflammatory smear, 14.7% had active bacterial infection, 17.65% had active candida infection and 5.88% had high-grade intraepithelial lesion (CIN 3).Conclusions: The incidence of high-grade lesion for cervical cancer is high among the rural population and they are susceptible to develop the cancer. Regular screening for cancer of uterine cervix is of need among people of lower socio economic status. Awareness should be created on cervical cancer and its complications
Probiotic properties of the riboflavin producing Lactobacillus fermentum strain isolated from yoghurt sample
The probiotic properties of the riboflavin producing lactic acid bacterium, Lactobacillus fermentum MTCC 8711 were evaluated. The strain was resistant to the acidic environment with the pH of 3.5 and more than 100% survivability of the cells was observed after 4 h. Similarly, 85% survivability was observed in the presence of 0.3% (w/v) bile salts. The strain exhibited β- galactosidase activity by blue colored colony formation in the MRS agar plates with X-gal and IPTG. Further, it was found to be a medium acidifier with a DpH value of 0.96 after 5 h of growth. The strain was also able to reduce the cholesterol up to 50% in the presence of cholesterol and bile salts. Since the strain possesses the basic properties of the probiotics and produces riboflavin, it could be considered as a better starter culture in the fermented food industry. Probiotic properties of the riboflavin producing Lactobacillus fermentum strain isolated from yoghurt sampleS. Jayashree*, K. Jayaraman and G. KalaichelvanSchool of Biosciences and Technology, VIT University, Vellore-632 014, Tamil Nadu, India*Corresponding Author, Email: [email protected]; Phone- 91-416-220- 2901; Fax- 91-416-224-3092Cite This Article as: S. Jayashree, K. Jayaraman and G. Kalaichelvan. 2010. Probiotic properties of the riboflavin producing Lactobacillus fermentum strain isolated from yoghurt sample. J. Ecobiotechnol. 2(2): 11-16.ÂÂ
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