5,606 research outputs found
MODLEACH: A Variant of LEACH for WSNs
Wireless sensor networks are appearing as an emerging need for mankind.
Though, Such networks are still in research phase however, they have high
potential to be applied in almost every field of life. Lots of research is done
and a lot more is awaiting to be standardized. In this work, cluster based
routing in wireless sensor networks is studied precisely. Further, we modify
one of the most prominent wireless sensor network's routing protocol "LEACH" as
modified LEACH (MODLEACH) by introducing \emph{efficient cluster head
replacement scheme} and \emph{dual transmitting power levels}. Our modified
LEACH, in comparison with LEACH out performs it using metrics of cluster head
formation, through put and network life. Afterwards, hard and soft thresholds
are implemented on modified LEACH (MODLEACH) that boast the performance even
more. Finally a brief performance analysis of LEACH, Modified LEACH (MODLEACH),
MODLEACH with hard threshold (MODLEACHHT) and MODLEACH with soft threshold
(MODLEACHST) is undertaken considering metrics of throughput, network life and
cluster head replacements.Comment: IEEE 8th International Conference on Broadband and Wireless
Computing, Communication and Applications (BWCCA'13), Compiegne, Franc
Magnetohydrodynamic Viscous Flow Over a Shrinking Sheet With Second Order Slip Flow Model
In this paper, we investigate the magnetohydrodynamic viscous flow with
second order slip flow model over a permeable shrinking surface. We have
obtained the closed form of exact solution of Navier-Stokes equations by using
similarity variable technique. The effects of slip, suction and magnetic
parameter have been investigated in detail. The results show that there are two
solution branches, namely lower and upper solution branch. The behavior of
velocity and shear stress profiles for different values of slip, suction and
magnetic parameters has been discussed through graphs.Comment: 13 Pages, 8 Figures. Accepted for Publication in Heat Transfer
Researc
Mixed Infection of Hard Red Winter Wheat with High Plains Virus and Wheat Streak Mosaic Virus from Wheat Curl Mites in Nebraska
A new disease of wheat and corn caused by the High Plains virus (HPV) has been observed in the High Plains region of western United States. HPV is transmitted by the wheat curl mite, Aceria tosichella, which is also the vector of wheat streak mosaic virus (WSMV). In the field it is extremely difficult to visually differentiate plants infected with WSMV from those with HPV. An indirect protein-A sandwich enzyme-linked immunosorbent assay (PAS-ELISA) and Western blot analysis were used to identify WSMV and HPV. Samples of wheat curl mites were collected from arbitrarily chosen sites from commercial wheat plantings in 1995 and 1996 and used to infest caged wheat plants. After 3 weeks, leaf samples were harvested and assayed. Both Western blot analysis and PAS-ELISA were effective at identifying samples positive for WSMV and HPV, both alone and in mixed infections. Western blot results showed that over the 2 years, 65% of the samples were positive for WSMV, 46% were positive for HPV, and mixed infections were found in 40% of the samples. HPV presence was verified with similar results from field collected plant samples. These levels of virus indicate an unexpectedly high incidence of HPV in wheat curl mite populations in Nebraska
Power quality improvement using ultra capacitor based dynamic voltage restorer with real twisting sliding mode control
Introduction. Power quality is a major problem in today's power system, since it may have an impact on customers and utilities. Problem. Power quality is important issue of financial consequences for utilities, their consumers and load apparatus vendors. Voltage sag/swell are the most significant and usually occurring power quality issues in a secondary distribution system for sensitive loads. Goal. Dynamic voltage restorer is a fast, flexible, effective and dynamic custom power device can be used to compensate voltage sag/swell with integration of energy storage. Ultra capacitors have ideal properties of great power density and low energy density for elimination of voltage sag/swell. Their performance is mostly determined by the control strategy established for switching of voltage source converters. Originality. In this research, a strategy for the voltage source converter of dynamic voltage restorer based on the real twisting sliding mode control and ultra capacitor is developed to correct the fault that successfully eliminates the impacts of voltage sag/swell. Methodology. Ultra capacitor along with real twisting sliding mode control gives the more robustness and faster response, with also increasing the compensation time of the dynamic voltage restorer. Testing environment. To evaluate the performance of the proposed control approach, the MATLAB / Simulink SimPower System tool box is employed. Practical values. According to Simulation results clearly shows that the ultra capacitor along with real twisting sliding mode control effectively eliminate the voltage sag/swell in a very short time of 2 ms as compared to IEEE standards that is 20 ms, with less than 5 % total harmonic distortion for sensitive loads as per Information Technology Industry Council Curve and SEMI-F-47 Standards.Вступ. Якість електроенергії являє собою серйозну проблему в сучасній енергосистемі, оскільки вона може впливати на споживачів та комунальні служби. Проблема. Якість електроенергії є важливим питанням з точки хору фінансових наслідків для комунальних підприємств, їх споживачів та постачальників апаратури-навантажень. Провали/стрибки напруги є найбільш серйозними проблемами з огляду на якість електроенергії, які зазвичай виникають у вторинній системі розподілу для чутливих навантажень. Мета. Динамічний відновник напруги — це швидкий, гнучкий, ефективний і динамічний пристрій живлення, який можна використовувати для компенсації провалів/стрибків напруги за допомогою інтеграції накопичувача енергії. Суперконденсатори мають ідеальні властивості високої щільності потужності та низької щільності енергії для усунення провалів/стрибків напруги. Їх ефективність переважно визначається стратегією управління, встановленої для комутації перетворювачів джерел напруги. Оригінальність. У цьому дослідженні розроблено стратегію для перетворювача джерела напруги динамічного відновника напруги на основі керування реальним ковзним режимом скручування та суперконденсатора для виправлення несправності, яка успішно усуває наслідки провалу/стрибка напруги. Методологія. Суперконденсатор разом із керуванням реальним ковзним режимом скручування забезпечує більшу надійність та швидшу реакцію, а також збільшує час компенсації динамічного відновника напруги. Середовище для тестування. Для оцінки ефективності запропонованого підходу до управління використовується комплекс програмного забезпечення MATLAB/Simulink SimPower System. Практична цінність. Згідно з результатами моделювання ясно видно, що суперконденсатор разом з керуванням реальним ковзним режимом скручування ефективно усувають провали/стрибки напруги за дуже короткий час 2 мс у порівнянні зі стандартами IEEE, у відповідності до яких він становить 20 мс, із загальним спотворенням гармонік менше 5 % для чутливого навантаження відповідно зі стандартами Information Technology Industry Council Curve та SEMI-F-47
Bacterial ventriculoperitoneal shunt infections: changing trends in antimicrobial susceptibility, a 7-year retrospective study from Pakistan
BACKGROUND: Ventriculoperitoneal (VP) shunt infections in adults represent a severe complication and make treatment more challenging. Therefore, drug susceptibility patterns are crucial for therapeutic decisions and infection control in neurosurgical centers. This 7-year retrospective study aimed to identify the bacteria responsible for adult VP shunt infections and determine their drug susceptibility patterns. METHODS: This single-center study was performed from 2015 to 2021 in Lahore, Pakistan, and included CSF cultures from VP shunt infections. Demographic data, causative organisms, and antimicrobial susceptibility testing results were collected. Multivariate analysis of variance (MANOVA) and two-sample t-tests were used to analyze and compare the antibiotic sensitivity trends over the study period. RESULTS: 14,473 isolates recovered from 13,937 CSF samples of VP shunt infections were identified and analyzed for their susceptibility patterns to antimicrobials. The proportion of Gram-negative and Gram-positive bacteria were 11,030 (76%) and 3443 (24)%, respectively. The predominant bacteria were Acinetobacter species (n = 5898, 41%), followed by Pseudomonas species (n = 2368, 16%) and coagulase-negative Staphylococcus (CoNS) (n = 1880, 13%). 100% of Staphylococcus aureus (S.aureus) and CoNS were sensitive to vancomycin and linezolid (n = 2580). However, 52% of S. aureus (719/1,343) were methicillin-resistant Staphylococcus aureus (MRSA). Acinetobacter showed maximum sensitivity to meropenem at 69% (2759/4768). Pseudomonas was 80% (1385/1863 sensitive to piperacillin-tazobactam, Escherichia coli (E. coli) showed 72% to amikacin (748/1055), while Klebsiella spp. was 57% (574/1170) sensitive to piperacillin-tazobactam. The sensitivity of piperacillin-tazobactam and meropenem for Gram-negative bacteria decreased significantly (p < 0.05) over 7 years, with 92.2% and 88.91% sensitive in 2015 and 66.7% and 62.8% sensitive in 2021, respectively. CONCLUSION: The significant decrease in the effectiveness of carbapenem and beta-lactam/beta-lactamase inhibitor combination drugs for the common Gram-negative causative agents of VP shunt infections suggests that alternative antibiotics such as colistin, fosfomycin, ceftazidime/avibactam, ceftolozane/tazobactam, and tigecycline should be considered and in consequence included in testing panels. Additionally, it is recommended to adopt care bundles for the prevention of VP shunt infection
Protective Effect of Bombyx mori L Cocoon (Abresham) and its Formulations against Isoproterenol-Induced Cardiac Damage
Purpose: To investigate the potential activity of Bombyx mori and its formulations against isoproterenol (ISO) induced cardiotoxicity.Methods: Wistar rats were orally pretreated with the ethanol extract of Bombyx mori cocoons in two doses (250 and 500 mg/kg) for 30 days; rats were similarly pretreated with its polyherbal formulations incorporating Khamira Abresham sada (KAS) and Khamira Abresham Hakim Arshadwala (KAHAW) (800 mg/kg), standard drug metoprolol (10 mg/kg) and normal saline for 30 days. Cardiotoxicity was induced by administration of isoproterenol (ISO, 85 mg/kg, subcutaneous) given twice on days 29 and 30 in all six pre-treated groups (n = 6) except the normal control. Cardiotoxicity was assessed by morphological and biochemical evaluation and further confirmed by histopathological studies.Results: Pretreatment with Bombyx mori (500 mg/kg), KAHAW and KAS significantly decreased (p < 0.01) the heart weight:body weight (HW:BW) ratio; significantly decreases the elevated activities of the cardiac marker enzymes, namely, asparate transaminase (AST) (p < 0.01), alanine transaminase (ALT) (p < 0.01), lactate dehydrogenase (LDH) (p < 0.01) ,creatinine kinase (CK-MB) (p < 0.01) and thiobarbituric acid reactive substances (TBARS) (p < 0.01) similar to the standard drug metoprolol (p < 0.01) in ISO-injected rats. Pre-treatment of rats with Bombyx mori (500 mg/kg), KAS, KAHAW and metoprolol challenged with ISO also showed absence of troponin. Pretreatment with B. mori (500 mg/kg), KAHAW and KAS significantly increased the activities of Superoxide dismutase (SOD) (p < 0.01), Tissue glutathione (GSH) (p < 0.01) and catalase (p < 0.01) similar to the standard drug metoprolol (p < 0.01).Conclusion: The findings of this study indicate that Bombyx mori as well as its polyherbal formulations exerts potent cardioprotection against isoproterenol-induced cardiotoxicity. This effect is comparable with that of metoprolol.Keywords: Bombyx mori, Myocardial necrosis, Oxidative stress, Cardiotoxicity, Khamira Abresham, Metoprolol, Isoprotereno
Exploring cucumber extract for skin rejuvenation
This study was designed to develop a topical skin-care cream water in oil (w/o) emulsion of 3% cucumber extracts versus its vehicle (Base) as control and evaluates its effects on skin-melanin, skin erythema, skin moisture, skin sebum and transepidermal water loss (TEWL). Hydroalcohol.c cucumber (Cucumis sativus) fruit extract was entrapped in the inner aqueous phase of w/o emulsion. Base containing no extract and a formulation containing 3% concentrated extract of C. sativus was formulated. The odour was adjusted with few drops of lemon oil. Both the base and formulation were stored at different storage conditions for a period of 4 weeks to predict their stability. Different stability parameters that is: Physical stability, centrifugation and pH were monitored at different time intervals. Both the base and formulation were applied to the cheeks of 21 healthy human volunteers for a period of 4 weeks. The expected pharmaceutical stability of creams was achieved from 4 weeks in vitro study period. Odour disappeared with passage of time due to volatilization of lemon oil. The base showed insignificant (p > 0.05) effects on all skin parameters except sebum that was not significant, whereas the formulation showed statistically significant (p.0.05) effects on skin sebum secretion. TEWL and erythema was increased while skin melanin and skin hydration level was decreased by formulation. However these effects were statistically insignificant (p > 0.05). The results showed a good stability over 4 weeks of observation period of both base and formulation and the formulation has anti sebum secretion, bleaching and moisturizing effects.Key words: Cucumber extract, melanin, skin moisture, skin sebum, transepidermal water loss (TEWL)
Phylogeny of Artemisia L.: Recent developments
In this review, classification and phylogeny of genus Artemisia L. is discussed. Its centers of diversity lie in the temperate and cold temperate regions of the Eurasia, North America and Asia. Artemisia has two basic chromosome numbers, with ploidy levels x=9 and x=8. Chromosome number in diploid is most often 2n=18 or 16. The genus is divided into five large groups Absinthium DC., Artemisia L., Dracunculus Besser, Seriphidium Besser and Tridantatae (Rydb.) McArthur. Its phylogeny was based on the two hypothesized evolutionary trends, loss of fertility in the disc florets and loss of ray florets. Recently its molecular phylogeny based on internally transcribed spacer (ITS), externally transcribed spacer (ETS) regions of the DNA and chloroplast DNA suggested that the genus Artemisia is a monophyletic but it could not resolve the problem of infra-generic classification. This study revealed that there is need to search new genome regions to establish a natural classification based on modern molecular techniques
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Automotive leaf spring design and manufacturing process improvement using failure mode and effects analysis (FMEA)
Nowadays human safety and comfort are the most considerable parameters in designing and manufacturing of a vehicle, that is why every organization ensures the quality and reliability of components used in the vehicle. Leaf spring is also a component of vehicle which plays an important role in human safety and comfort. It acts as a structural member and an integral part of suspension system. It is important to eliminate the failures in designing and manufacturing process of leaf springs because of its importance in functionality and safety of vehicle. In this research, failure mode and effects analysis has been used to analyze and reduce the risks of 42 possible failures that can occur in automotive leaf spring. It starts from determining, classifying, and analyzing all potential failures and then rating them with the help numeric scores. The four numeric scores namely severity, occurrence, detection, and Risk Priority Number (RPN) are used to find the high potential failures of semi-elliptical leaf springs. In the end, actions are recommended for RPN greater than 250, to increase quality and reliably of product. </jats:p
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