Investigating viscous damping using a webcam

We describe an experiment involving a mass oscillating in a viscous fluid and analyze viscous damping of harmonic motion. The mechanical oscillator is tracked using a simple webcam and an image processing algorithm records the position of the geometrical center as a function of time. Interesting information can be extracted from the displacement-time graphs, in particular for the underdamped case. For example, we use these oscillations to determine the viscosity of the fluid. Our mean value of 1.08 \pm 0.07 mPa s for distilled water is in good agreement with the accepted value at 20\circC. This experiment has been successfully employed in the freshman lab setting.Comment: 13 pages, 5 figure

Phase transitions in holographic QCD and instanton crystals

textWe investigate phase transitions in holographic models of QCD. In chapter I, we explore the effect of constant external U(1) fields on the physics of chiral symmetry breaking, as realized in the D3/D7 model. We discover that this model exhibits the phenomenon of magnetic catalysis, which is what one would expect from a weakly coupled field theory intuition. In chapter II, we continue exploring the effect of external U(1) fields but now on the backreacted D3/D7 model, where the backreaction is obtained via a smearing procedure. We again find the magnetic catalysis effect, however the results differ from the previous case depending on the backreaction parameters. In chapter III, we investigate lattices of instantons in the D4/D8 model of chiral symmetry breaking. These instanton lattices can change dimensionality, and in particular we investigate the 1D [right arrow] 2D transition as a simpler case of the more complicated 3D [right arrow] 4D transition which is conjectured to be holographically dual to the baryonic to quarkyonic phase transition. Besides this interpretation, one could also view this as a hypothetical condensed matter system. We have a lattice of instantons dominated by two-body forces, whose interactions depend not only on their mutual distance in physical space but also on their relative orientations in the internal isospace. We obtain a rich variety of instanton crystals whose description could serve to be useful beyond holography.Physic

Synthesis and Characterization of Silica Supported Co/Nb Bimetallic Catalyst for the Production of Synthetic Fuel via Fischer-Tropsch

Fischer Tropsch synthesis has received considerable attention as it offers a viable alternative to produce liquid fuels and chemicals from non-petroleum carbon resources such as biomass, coal and natural gas. The objective of this work is to synthesize, characterize and study the performance of supported bimetallic cobalt (Co) and niobium (Nb) catalyst in Fischer Tropsch synthesis. Supported bimetallic Co and Nb catalyst have been formulated using reverse microemulsion method. 5wt% of nano particles metal loadings were deposited on silica (SiO2) support. The effect of different metal loading composition of Co and Nb (100:0, 95:5, 90:10, 85:15) on the physiochemical properties of the catalyst has been investigated. The physiochemical properties of the catalyst were studied using field emission electron microscopy (FESEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) and N2 physical adsorption. The FTS performance of the synthesized catalyst was examined in a fixed-bed Microreactor at 220oC, atmospheric pressure and H2/CO ratio of 2:1. Results from the N2 physical adsorption shows that addition of niobium decreases the pore area and volume. It also changes the textural structure from non porous to porous. FESEM and TEM results have shown that the metal particles are well dispersed on the support. The average particle sized ranges from 10.61 nm - 25.5 nm. Introduction of niobium to the catalyst changes its shape from spherical to hexagonal and forms fringes on the particles. This indicates the crystalline structure of cobalt particles. The FTS results exhibit that the CO conversion increases with the amount of Nb in the catalyst. The highest CO conversion is obtained from Sample D (85Co15Nb) which is 70.07%. Sample B (95Co5Nb) showed the lowest selectivity towards CH4 (6.58%) and highest selectivity towards C5+ hydrocarbons i.e. 8.79%. All the samples catalysts display high olefin productivity, indicating that the catalysts synthesized are more suitable for olefin production

パキスタン国力ラコルム・ヒマラヤ山脈インダス川上流城における河川流量と流出時期に及ぼす気候変動の影響

京都大学新制・課程博士博士(工学)甲第23429号工博第4884号新制||工||1763(附属図書館)京都大学大学院工学研究科社会基盤工学専攻(主査)教授 田中 茂信, 准教授 田中 賢治, 准教授 佐山 敬洋学位規則第4条第1項該当Doctor of Philosophy (Engineering)Kyoto UniversityDFA

AN ENHANCED WAVELET BASED METHOD FOR NUMERICAL SOLUTION OF HIGH ORDER BOUNDARY VALUE PROBLEMS

The Legendre wavelet collocation method (LWCM) is suggested in this study for solving high-order boundary value problems numerically. Eighth, tenth, and twelfth-order examples are used as test problems to ensure that the technique is efficient and accurate. In comparison to other approaches, the numerical results obtained using LWCM demonstrate that the method's accuracy is very good. The results indicate that the method requires less computational effort to achieve better results

Successful anesthetic management of patient with stiff person syndrome

We herein describe the successful anesthetic management of a patient with stiff person syndrome undergoing right total hip replacement under spinal anesthesia. We also describe the problems associated with general anesthesia. The advantage of using regional anesthesia in these patients is the avoidance of muscle relaxants. The use of general anesthesia carries the risk of hypotonia in stiff person syndrome postoperatively due to enhancement of γ aminobutyric acid (GABA) action on synaptic transmission by drugs that have a γ GABA agonistic action

Obstetric patients requiring critical care: Retrospective study in a tertiary care institute of Pakistan

Background: The outcome of obstetric patients admitted to the intensive care unit (ICU) depends on the number of factors. The objective of this study is to review the outcomes of these patients with regard to pregnancy status, source of admission, and their presenting illness at time of admission to ICU. Materials and Methods: A retrospective study was undertaken for all obstetric patients admitted to the ICU of a private tertiary care hospital of Pakistan from 2014 to 2018. The data were reviewed thorough ICU log sheet, electronic medical records, and online laboratory data. The data included patient demographics, pregnancy status, mode of admission, length of stay, laboratory investigation, presenting disease, and outcomes in terms of death or survival. Results: Obstetric patients accounted for 3.8% for all ICU admission with overall mortality of 11.1%. There was no statistically significant difference in the mortality rate with respect to presenting illness; however, morality was highest (37.5%) in patients with pre-eclampsia. A majority (54.2%) of the ICU admission were due to hemorrhagic/hematological causes followed by cardiovascular causes (33.1%). A statistically significant increase in mortality rate was observed in patients admitted through emergency compared with patients from within hospital (P \u3c 0.0005). Conclusion: Patients coming through emergency as referral patients were found to have the highest mortality. There is dire need to uplift the primary and secondary tertiary care centers in developing countries, where early treatment can be provided and high-risk cases can be picked up with early referral to tertiary care center