170 research outputs found
Power quality improvement by using non-linear sliding mode controller with the dynamic voltage restorer
The essential issue of the power system network is power quality. The bus voltage
must be maintained as a sinusoidal waveform. Many disturbances affect the supply
voltage, such as notching, transients, voltage sag/swell. The major power quality
problems are voltage sag/swell and harmonics, which cause tripping or malfunctioning
the equipment. The linear PID controller's output suffers from a high amplitude of
error when the input signals are noisy. This thesis gives an effective solution to protect
the sensitive loads from disturbances by utilizing the dynamic voltage restorer. It is
defined as a controlled voltage source connected in series between the sensitive loads
and the network through a series transformer to inject a proper voltage magnitude to
keep the sensitive loads at a constant value. The two non-linear controllers employ a
robust differentiator known as an approximate sliding mode differentiator (ACSMD)
with a non-linear sliding variable named a terminal PID sliding variable (TPIDSV) or
arctan PID sliding variable (ARTPIDSV). Simulation results were carried out by
MATLAB/Simulink to investigate the performance of the proposed controllers. The
performance improvement obtained from the proposed techniques upon comparison
with the case study as a linear PID controller, the steady-state error 85%-99%, the total
harmonic distortion 2%-51%, the voltage sag indices 85%-99% and the load voltage
magnitude 0.2%-8.7% for voltage sag and 0.08%-2.9% for voltage swell in all cases.
The results illustrated the DVR structure's ability to overcome the system's
disturbances, maintaining the voltage magnitude of the sensitive loads at a constant
value, minimizing the steady-state of error, and keeping the THD at an IEEE standard.
The DVR system performance is evaluated by utilizing three types of voltage sag
indices
Sensitivity of tomato (Solanum lycopersicum) cultivars from Turkey to bacterial speck (Pseudomonas syringae pv. tomato)
The susceptibility of 93 different tomato cultivars that are commonly grown in greenhouses and field in the western Mediterranean region of Turkey have been assessed for resistance to bacterial speck disease caused by Pseudomonas syringae pv. tomato strains. The disease severity indexes (DSI) varied between zero and four for the tomato cultivars. Seven tomato cultivars showed hypersensitive reactions against strains of P. syringae pv. tomato carrying the avrpto1 gene. Six of these seven tomato cultivars had the PTO gene coding for resistance against bacterial speck. The PTO sequences from the tomato cultivars Atalay, Party, Petrus, Piccadilly, Prenses and Tyty had similarity of 94, 93, 94, 92, 95 and 94%, respectively, with the PTO sequence of Lycopersicon esculentum VFNT Cherry (AF220603), and had similarity of 98, 98, 96, 95, 100 and 98%, respectively, with the PTO sequence of Lycopersicon pimpinellifolium Rio Grande 76R (AF220602). These findings indicate a considerable variation in bacterial speck resistance and will aid in the choice of parental lines for breeding new tomato cultivars with resistance to bacterial speck.Keywords: avrpto, Mediterranean region, polymerase chain reaction, PTOAfrican Journal of Biotechnology Vol. 12(15), pp. 1793-180
Enhancement Techniques of Boiling Heat Transfer
The aim of this study is to investigate pool boiling performance of water under atmospheric pressure by two techniques. The first method is by adding small amounts of surfactants, and the second way is by using structured surfaces.
The first technique is investigated experimentally with environmentally friendly surfactants. The surfactants chosen for the study are an ionic sodium lauryl sulfate (SLS), nonionic ECOSURF™ EH-14, and nonionic ECOSURF™ SA-9. It is observed that adding a small amount of surfactant alters the water boiling phenomenon significantly. Boiling curves for different concentrations are shifted to the left. The wall temperature drops greatly with an increase in the concentration of aqueous surfactant solutions. Also, it is found that the optimum boiling heat transfer augmentation of SLS is higher than that of EH-14 and SA-9 compared to water. The maximum enhancement obtained is 66.27% for 300ppm aqueous SLS solution. However, the maximum enhancement in heat transfer coefficient is 24.31% for 1600ppm EH-14 and 22.09% for 200ppm SA-9. Boiling visualization shows that boiling with surfactant solutions compared with that in pure water is more vigorous. Bubbles are smaller in size, activate continuously, and collapse quickly. Also, the bubble departure frequency is higher than that of pure water. Compared with water, it is found that time required to reach boiling point for surfactant concentrations is reduced significantly. The maximum reduction for each surfactant was 14.6% for 100ppm SLS, 9% for 800ppm EH-14, and 12.49% for 300ppm SA-9.
For the second technique, an experimental study is conducted to investigate the performance of various structured surfaces in pool boiling. Surfaces with rectangular channels, holes, and mushroom fins are manufactured first and then studied. The results show that boiling heat transfer can be augmented by structured surfaces. The maximum enhancement is 51.66% achieved by Holed 3 surface compared with plain surface. As the spacing between channels or holes is decreased, the heat transfer coefficient is increased. The bubbles with holed surfaces and mushroomed surface have almost spherical shape, while in plain and grooved surfaces they have an irregular shape. Time to reach boiling point is measured. It is found that some enhanced surfaces show a higher reduction to others. For heat flux of 27.91 kW/m2, 8.58% enhancement in time to reach boiling point for Grooved 1 surface is attained, while at a heat flux of 35.08 kW/m2 the maximum reductions achieved are 8.74% for Mushroomed surface and 8.19% for Holed 1 surface. Also, the different regimes of pool boiling are observed by droplet dropping tests.
Also, the total evaporation time of a water droplet was measured and compared with the results of other studies. The results show that the evaporation times in the natural convection and nucleate boiling regimes are significantly shorter than those in film boiling regime. For natural convection and nucleate boiling regimes, the droplet evaporation time varies between 1s to 31s, while for film boiling regime it varies between 104s to 123s
Extend Wireless Network's Lifetime Based on Developing Gossiping Routing Algorithm
Prolong node's lifetime that is limited by its battery, as long as possible is an important factor during wireless sensor network designing. Several routing algorithm have been adopted to manage the energy strategy of WSNs. Multi-hoping is considered to be data transmission technique in WSNs, and Gossiping is one of well-defined multi-hopping as an epidemic routing algorithm. Gossip algorithm constructs its routing based on random selection of intermediate nodes, thus leads to its inefficiency. In this paper, three algorithms proposed for developing Gossip algorithm, DGossip, EN_Gossip and ENL_Gossip. Network lifetime improved by considering the information of nodes location, energy and their distance to the base station. The simulation executed in MATLAB, and the results of the proposed algorithms show that they are more efficient than LGossip and ELGossip and prolong the overall network lifetime. Keywords: Gossiping, epidemic routing algorithm, DGossip, Network life time, EN_Gossip, ENL_Gossip
Assessment feeds learning
Bacheloroppgave, grunnskolelærerutdanning, 2013Sammendrag: Denne bacheloroppgaven er et kvantitativt studie om egenvurdering og vurdering for læring. Oppgavens problemstilling har med hvordan dette kan være med å påvirke elevenes læring. Det er to 8. klasser fra samme skole som har blitt undersøkt, hvor det har blitt gjort noen forskjeller i forberedelsene frem mot prøven. Gjennomsnittskarakteren har blitt sammenlignet opp mot den tidligere gjennomsnittskarakteren til klassene. Undervisningen har vært lik for begge klasser, men den ene klassen fikk et egenvurderingsskjema i tillegg til undervisningen. Et av målene var å få elevene i denne klassen til å fokusere mer på å vurdere seg selv i arbeidet med å forberede seg til prøven. Forskjellen i gjennomsnittskarakteren mellom klassene har blitt diskutert. Teori og resultater drøftes fra ulike perspektiver for å få med flere aktuelle vinklinger.Summary: This Bachelor quantitative study on the self-assessment and assessment for learning. The topic question is about how this can affect learning for the students. Two Norwegian 8. Grade school classes have been tested, and some few differences have been made between the classes in the preparations for a test. The average grade before and after the test will be compared. The teaching has been the same for both classes, but one of the classes got a self-assessment form before the test. One of the goals was to make the students in this class more focused on using self-assessment in preparations before the test. Differences in the average grade between the classes before and after have been discussed with critical eyes. Actual theory and views form actual angles on the results is presented
Vasoactive intestinal peptide (VIP) differentially affects inflammatory immune responses in human monocytes infected with viable Salmonella or stimulated with LPS
We compared the effect of VIP on human blood monocytes infected with Salmonella typhimurium 4/74 or stimulated with LPS. VIP (10−7 M) increased monocyte viability by 24% and 9% when cultured for 24 h with 4/74 or Salmonella LPS (100 ng/ml), respectively. Significantly increased (P < 0.05) numbers of 4/74 were also recovered from monocytes co-cultured with VIP after 6 h post-infection (pi) and this remained high after 24 h pi. Both 4/74 and LPS increased (P < 0.05) the concentration of TNF-α, IL-1β and IL-6 measured in monocyte supernatants. However, LPS induced this effect more rapidly while, with the exception of IL-6, 4/74 induced higher concentrations (P < 0.05). VIP significantly decreased (P < 0.05) TNF-α and IL-1β production by 4/74-infected monocytes after 6 pi, but only after 24 h in LPS-cultured monocytes. This trend was reversed for IL-6 production. However, TNF-α and IL-1β production by 4/74-infected monocytes, cultured with VIP, still remained higher (P < 0.05) than concentrations measured in supernatants cultured only with LPS. VIP also increased (P < 0.05) production of anti-inflammatory IL-10 in both 4/74 and LPS cultures after 24 h. We also show a differential effect of VIP on the expression of TNFα and IL-6 receptors, since VIP was only able to decreased expression in LPS-stimulated monocytes but not in 4/74-infected monocytes.
In conclusion, we show a differential effect of VIP on human monocytes infected with virulent Salmonella or stimulated with LPS. Our study suggests that the use of VIP in bacteraemia and/or sepsis may be limited to an adjunctive therapy to antibiotic treatment
Experimental and Numerical Investigation of Self Compacting Reinforced Concrete Dapped End Beams Strengthened with CFRP Sheets
الهدف من هذه الدراسة هو التحري عمليا عن سلوك الاعتاب الخرسانية الذاتية الرص ذات النهايات المستدقة المقواة بشرائح الياف الكاربون البوليمرية، ثم نظريا بواسطة برنامج ANSYS. يتكون البرنامج من اختبار 14 عينة ذات أبعاد (200 × 400 × 1500 ملم) مع قيمتين من (a/d) وهي (1.5 و1.0). وكانت اثنتين من الاعتاب مرجعية (بتسليح كامل) كما تم تقوية الاعتاب الأخرى في مناطق ((hanger & nib بعدة تشكيلات بشرائح الكاربون البوليمرية لنفس القيم من (a/d)، وشملت المقارنة بين النتائج منحنيات التحمل والهطول. وقد وجد أن طريقة STM متحفظة جدا بطريقة ما، وان تقليل حديد nib بنحو (60٪)، قلل من حمل الفشل بحوالي (35٪ و15٪) للقيمتين (a /d). فيما يتعلق بالعينات المقواة، لوحظ أن التقوية بشرائح الياف الكاربون البوليمرية المائلة بزاوية (450) أسفرت عن نتائج أفضل بالمقارنة مع االتشكيلات الأخرى. كان التحسن في سعة التحميل حوالي (23٪) لـ (a/d=1.5 , 1.0). كذلك وجد أن التحليل اللاخطي المعتمد في هذا العمل مقارنة مع فحوصات العملي أسفر عن توافق جيد مع فرق يبلغ حوالي (12٪).This study aims to investigate experimentally the behavior of self-compacting reinforced concrete dapped end beams strengthened with CFRP sheets and, then theoretically by ANSYS 15.0 software. The experimental program consists of testing 14-specimens each of dimensions (200x400x1500 mm) with two values of Shear span to depth effective (a/d), namely (1.5 and 1.0). Two of the beams are a control beams (with full reinforcement), and four beams with reduced reinforcement in hanger and nib regions. The other beams have been strengthened with several configurations by CFRP sheets for the same values of (a/d), the comparison between results included load-deflection curves and cracked specimens. It was found that the strut and tie model (STM) is very conservative somehow, reduction the nib reinforcements by about (60%), in reduction in failure load by about (35% and 15%) for the two values of (a/d). With respect to the strengthened specimens, it observed that the strengthening with inclined CFRP strips (450) yielded better results in comparison with other configurations. The improvement in load capacity was about (23%) for (a/d=1.5 and 1.0). Also, it is found that the nonlinear model adopted in the present work compered the experimental tests yielded a good agreement with difference of about (12%)
Clinicopathologic features predictive of distant metastasis in patients diagnosed with invasive breast cancer
Purpose: National Comprehensive Cancer Network and European Society for Medical Oncology guidelines suggest screening for distant metastasis (M1) in symptomatic patients or those with locally advanced breast cancer. These guidelines are based on studies that often used pathologic staging for analysis. Physician variability in screening for M1 has also resulted in overuse of diagnostic tests. We sought to identify clinicopathologic features at diagnosis that could guide testing for metastatic disease.Methods: Patients diagnosed with invasive breast cancer between January 2014 and December 2015 were identified from our institutional database. Demographic and clinical variables were collected, including receptor profiles and clinical TNM staging. Rates of upstaging for each clinical stage and rates of concordance of pathologic and clinical staging were analyzed. Univariate analysis and multivariate regression analysis (P \u3c .05) identified predictors of upstaging to stage IV disease.Results: A total of 370 patients met the inclusion criteria. Seventy patients (18.9%) had metastatic disease at diagnosis. The rate of upstaging for stages I, IIA, IIB, and III were 0%, 5.6%, 18.8%, and 36.6%, respectively. Advancing clinical stage, tumor size, and nodal status resulted in a significantly higher rate (P \u3c .001) of upstaging to M1 disease. Age and hormone receptor status were not associated with upstaging to stage IV disease. Clinical stages I-III were concordant with pathologic staging in 65(42.8%) of 152 patients (kappa\u27s index, 0.197; P \u3c .000).Conclusion: Advancing clinical stage, tumor size, and nodal status at diagnosis were predictive of upstaging to M1 disease in patients with breast cancer. Distant metastatic workup should be considered in patients with clinical stage IIB disease or higher
The therapeutic potential of vasoactive intestinal peptide (VIP) in the treatment of Gram-negative sepsis
Gram-negative bacteria are the most common cause of the sepsis and lipopolysaccharide (LPS) a major component of Gram-negative bacteria is known to be of major importance in the development of sepsis. Human infection with Salmonella, a Gram-negative bacterium, is associated with a number of cases of sepsis and is particularly important in childhood sepsis.
During salmonellosis, monocytes and macrophages produce a number of different pro-inflammatory mediators such as TNF-α, IL-1α, IL-12, IL-18, IFN-γ, reactive nitrogen species and oxygen species. Although the production of these inflammatory mediators is required for resolution of bacterial infections, they are contraindicated in diseases such as sepsis. In the initial (acute) phase of sepsis a Systemic Inflammatory Response Syndrome (SIRS) occurs in which inflammatory mediators are produced in high concentration, which can lead to organ failure and death. The SIRS phase is then replaced by a Compensatory Anti-inflammatory Response Syndrome (CARS) phase which leads to immunosuppression. The CARS phase can lead to secondary infection and subsequent mortality within 28 days of hospital admission.
To date, several studies have evaluated the role of vasoactive intestinal peptide (VIP) as an anti-inflammatory agent that may have therapeutic potential in septic patients both in vitro and in vivo. VIP has been shown to inhibit production of inflammatory mediators produced by human monocytes in response to LPS. The aim of the work described in this thesis was to investigate the therapeutic potential of VIP in sepsis using an ex vivo human monocytes model infected with viable Salmonella Typhimurium 4/74 (rather than LPS).
The study shows that VIP (10-7 M) stimulates an increase in the numbers of Salmonella recovered from infected human monocytes (MOI = 10). In addition, VIP also increases the survival rate of human monocytes infected with Salmonella. These two results may suggest a detrimental effect of VIP during bacteraemia and sepsis, since monocyte death may be beneficial during sepsis and bacterial overgrowth could lead to further increased LPS (and other antigen) stimulation of the immune system. However, VIP did significantly decrease Salmonella and LPS-induced TNF-α, IL-1β and IL-6 in monocyte supernatants. VIP also had a positive effect on IL-10 production in human monocytes infected with Salmonella or stimulated with LPS. Whether this suggests a possible detrimental effect of VIP is unknown but septic patients with high serum IL-10/ low TNF-α concentration ratio have previously been shown to have a poor prognosis. Higher IL-10 concentrations in infected monocytes (due to VIP) could also increase the CARS phase of disease with increased immunosuppression.
Flow cytometry and qPCR analyses showed that of all of the VIP receptors, VPAC1 was expressed most highly during Salmonella infection, or LPS stimulation, of human monocytes. Administration of VIP inhibited VPAC1 has been shown by many studies to be the most important receptor by which VIP inhibits production of inflammatory immune mediators, or increases IL-10 production from murine macrophages. Results in this thesis, therefore, suggested that Salmonella infection may promote VPAC1 expression and so provide a mechanism of inhibiting the production of inflammatory mediators in infected cells. This could then increase intracellular survival of Salmonella and provide a means of greater dissemination of the infection.
To ascertain how increased VPAC1 expression on the surface of monocytes may be achieved, analysis of the expression of known intracellular endosomal and exosomal constituents was performed. Confocal laser microscopy, using specific antibodies, showed that VPAC1 on the monocyte cell membrane was internalised within early endosomes (measured by co-localisation of VPAC1 and EEA1) rather than being degraded within lysosomes (measured by immunoreactivity to LAMP1). VPAC1 is then transported via a Rab11A recycling endosome and packaged in the Trans-Golgi network (TGN), shown by co-localisation of VPAC1/Rab11A and the TGN marker (TGN46). VPAC1 was then associated with Rab3a and calmodulin. The function of these latter two proteins in the docking of exosomes to the cell membrane is well known, thus suggesting that Salmonella induced VPAC1 was also recycled to the cell membrane within exosomes. VIP inhibited the expression of both Rab3a and calmodulin but not the co-localisation of VPAC1 with these two proteins. Further studies then showed that a calmodulin agonist (CALP1) increased VPAC1 expression on the surface of monocytes, while a calmodulin antagonist (W-7) decreased expression of VPAC1 on the surface of monocytes.
In conclusion, this thesis does present hitherto unknown data regarding Salmonella infection of human monocytes and the effects of VIP on infected monocytes. VIP has potential as an anti-sepsis therapy since it reduces the production of inflammatory mediators by Salmonella-infected and LPS-stimulated monocytes. However, the fact that VIP increases survival of infected human monocyte and increased growth of Salmonella in human monocytes may preclude its use in sepsis
Seroprevalence of Cytomegalovirus, Rubella, Herpes Simplex Type II and Chlamydia trachomatis in Pregnant and Abortion Women in Tikrit City
Aim of this study was to assess the Seroprevalence of Cytomegalovirus (CMV), Rubella, Herpes simplex II and Chlamydia trachomatis infections among pregnant and abortion women. This study was performed on 210 women who attended the gynecological consultative clinic in Salah El-Din general hospital during November 2021 until the end of march 2022.the sera samples were tested by ELISA assay for detection of specific IgG and IgM antibodies. Overall Seroprevalence was 10%, 5.7%, 3.3%, 1.9% of IgG for CMV, Rubella, Chlamydia trachomatis and HSV II respectively while IgM was 3.8%, 2.8%, and 1% for the last two respectively
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