Search results for: K. J. Karki

Authors: Krishna Poudel, Tahar Katuwal, Sujan Karki

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A rapid propagation and acclimatization method of large cardamom was optimized in this study. Sprouted rhizome buds were collected. The excised rhizome bud explants were cultured on semi solid culture media. The explants were cultured on Murashige and Skoog’s (MS) medium supplemented with different concentration and combinations of BAP (6-Benzyl-amino-purine) and IBA (Indole-3-butyric acid) for shoot and root induction. Explants cultured on MS basal medium supplemented with 1.0 mg/l BAP + 0.5 gm/l IBA showed the highest rate of shoot multiplication. In vitro shoots were rooted on to the half-strength MS basal media supplemented with 0.5 mg/l IBA. Rooted shoots were transplanted in the screen house for hardening process. These hardened plants were subsequently shifted into the netted nursery for further multiplication process.

Keywords: concentration, explants, hardening, rhizome

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Authors: Adewole A. Ayoade, Marshall R. Sweatt, John P. H. Steele, Qi Han, Khaled Al-Wahedi, Hamad Karki, William A. Yearsley

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Understanding the behavioral characteristics of sensors is a crucial step in fusing data from several sensors of different types. This paper introduces a practical, real-time approach to integrate heterogeneous sensor data to achieve higher accuracy than would be possible from any one individual sensor in localizing a mobile robot. We use this approach in both indoor and outdoor environments and it is especially appropriate for those environments like oil and gas refineries due to their sparse and featureless nature. We have studied the individual contribution of each sensor data to the overall combined accuracy achieved from the fusion process. A Sequential Update Extended Kalman Filter(EKF) using validation gates was used to integrate GPS data, Compass data, WiFi data, Inertial Measurement Unit(IMU) data, Vehicle Velocity, and pose estimates from Fiducial marker system. Results show that the approach can enable a mobile robot to navigate autonomously in any environment using a priori information.

Keywords: inspection mobile robot, navigation, sensor fusion, sequential update extended Kalman filter

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Authors: Sarthak Karki, Haribansha Timalsina

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Kanchan Arsenic Filter is an economical low cost and termed the most efficient arsenic removal filter system in South Asian countries such as Nepal. But when the effluent quality was evaluated, it was seen to possess a lower removal rate of arsenite species. In addition to that, greater pathogenic growth and loss in overall efficacy with time due to precipitation of iron sulphates were the further complications. This brings the health issue on the front line as millions of people rely on groundwater sources for general water necessities. With this paper, we analyzed the mechanisms and changes in the efficiency of the extant filter system when integrated with activated laterite and hair column beds, plus an additional charcoal layer for inhibiting pathogen colonies. Hair column have rich keratin protein that binds with arsenic species, and similarly, raw laterite has huge deposits of iron and aluminum, all of these factors helping to remove heavy metal contaminants from water sources. Further study on the commercialized mass production of the new proposed filter and versatility analysis is required.

Keywords: laterite, charcoal, arsenic removal, hair column

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Authors: P. Kumar, D. Eisenhauer, M. M. K. Yousef, Q. Shi, A. S. G. Khalil, M. R. Saber, C. Becker, T. Pullerits, K. J. Karki

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In impedance spectroscopy (IS) the response of a photo-active device is analysed as a function of ac bias. It is widely applied in a broad class of material systems and devices. It gives access to fundamental mechanisms of operation of solar cells. We have implemented a method of IS where we modulate the light instead of the bias. This scheme allows us to analyze not only carrier dynamics but also impedance of device locally. Here, using this scheme, we have measured the frequency-dependent photocurrent response of the thin-film planar and nano-textured Si solar cells using this method. Photocurrent response is measured in range of 50 Hz to 50 kHz. Bode and Nyquist plots are used to determine characteristic lifetime of both the cells. Interestingly, the carrier lifetime of both planar and nano-textured solar cells depend on back and front contact positions. This is due to either heterogeneity of device or contacts are not optimized. The estimated average lifetime is found to be shorter for the nano-textured cell, which could be due to the influence of the textured interface on the carrier relaxation dynamics.

Keywords: carrier lifetime, impedance, nano-textured, photocurrent

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Authors: Sujeeta Karki, Jeeban Poudel, Ja Hyung Choi, Sea Cheon Oh

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A lab-scale fluidized bed was used for the study of sewage sludge, a non-lignocellulosic biomass, torrefaction. The influence of torrefaction temperature ranging from 200–350 °C and residence time of 0–50 minutes on the physical and chemical properties of the torrefied product was investigated. Properties of the torrefied product were analyzed on the basis of degree of torrefaction, ultimate and proximate analysis, gas analysis and chemical exergy. The degree of torrefaction and chemical exergy had a positive influence on increasing the torrefaction temperature. Moreover, the effect of torrefaction temperature and residence time on the elemental variation of sewage sludge exhibited an increase in the weight percentage of carbon while the content of H/C and O/C molar ratios decreased. The product gas emitted during torrefaction was analyzed to study the pathway of hydrocarbons and oxygen-containing compounds. The compounds with oxygen were emitted at higher temperatures in contrast to hydrocarbon gases. An attempt was made to obtain the chemical exergy of sewage sludge. In addition, the study of various correlations for predicting the calorific value of torrefied sewage sludge was made.

Keywords: chemical exergy, degree of torrefaction, fluidized bed, higher heating value (HHV), O/C and H/C molar ratios, sewage sludge

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Authors: Sabita Karki

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Occupational health hazards are recognized as global problems for health care workers, it is quiet high in developing countries. It is increasing day by day due to change in science and technology. This study aimed to assess the knowledge and practice of occupational health hazards among the nurses. A descriptive, cross sectional study was carried out among 339 nurses working in three different teaching hospitals of the Kathmandu from February 28, 2016 to March 28, 2016. A self-administered questionnaire was used to collect the data. The study findings revealed that out of 339 samples of all 80.5% were below 30 years; 51.6% were married; 57.5% were graduates and above; 91.4% respondents were working as staff nurse; 56.9% were working in general ward; 56.9% have work experience of 1 to 5 years; 79.1% respondents were immunized against HBV; only 8.6% have received training/ in-service education related to OHH and 35.4% respondents have experienced health hazards. The mean knowledge score was 26.7 (SD=7.3). The level of knowledge of occupational health hazards among the nurses was 68.1% (adequate knowledge). The knowledge was statistically significant with education OR = 0.288, CI: 0.17-0.46 and p value 0.00 and immunization against HBV OR= 1.762, CI: 0.97-0.17 and p value 0.05. The mean practice score was 7.6 (SD= 3.1). The level of practice on prevention of OHH was 74.6% (poor practice). The practice was statistically significant with age having OR=0.47, CI: 0.26-0.83 and p value 0.01; designation OR= 0.32, CI: 0.14-0.70 and p value 0.004; working department OR=0.61, CI: 0.36-1.02 and p value 0.05; work experience OR=0.562, CI: 0.33-0.94 and p value 0.02; previous in-service education/ training OR=2.25; CI: 1.02-4.92 and p value 0.04. There was no association between knowledge and practice on prevention of occupational health hazards which is not statistically significant. Overall, nurses working in various teaching hospitals of Kathmandu had adequate knowledge and poor practice of occupational health hazards. Training and in-service education and availability of adequate personal protective equipments for nurses are needed to encourage them adhere to practice.

Keywords: occupational health hazard, nurses, knowledge, preventive practice

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Authors: Sameer Jung Karki, Gokhan Saygili

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The allowable bearing capacity of foundation systems is determined by applying a factor of safety to the ultimate bearing capacity. Conventional ultimate bearing capacity calculations routines are based on deterministic input parameters where the nonuniformity and inhomogeneity of soil and site properties are not accounted for. Hence, the laws of mathematics like probability calculus and statistical analysis cannot be directly applied to foundation engineering. It’s assumed that the Factor of Safety, typically as high as 3.0, incorporates the uncertainty of the input parameters. This factor of safety is estimated based on subjective judgement rather than objective facts. It is an ambiguous term. Hence, a probabilistic analysis of the bearing capacity of an isolated footing on a clayey soil is carried out by using the Monte Carlo Simulation method. This simulated model was compared with the traditional discrete model. It was found out that the bearing capacity of soil was found higher for the simulated model compared with the discrete model. This was verified by doing the sensitivity analysis. As the number of simulations was increased, there was a significant % increase of the bearing capacity compared with discrete bearing capacity. The bearing capacity values obtained by simulation was found to follow a normal distribution. While using the traditional value of Factor of safety 3, the allowable bearing capacity had lower probability (0.03717) of occurring in the field compared to a higher probability (0.15866), while using the simulation derived factor of safety of 1.5. This means the traditional factor of safety is giving us bearing capacity that is less likely occurring/available in the field. This shows the subjective nature of factor of safety, and hence probability method is suggested to address the variability of the input parameters in bearing capacity equations.

Keywords: bearing capacity, factor of safety, isolated footing, montecarlo simulation

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Authors: Karun Karki

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The Lhotshampa are Bhutanese people of Nepali origin who have been in Bhutan since the early 1600s. A significant number of these people migrated to Bhutan in the nineteenth century. The 1958 Nationality Law of Bhutan granted citizenship to many Lhotshampa people; however, in the late 1970s, the government of Bhutan introduced a series of laws and policies intended for the socio-political and cultural exclusion of the Lhotshampa due to their ancestry. These exclusionary policies and ethnic and racial injustices not only removed the rights and citizenship of the Lhotshampa but also forcibly displaced thousands of families with no choice but to seek refuge in Nepal. In this context, racism becomes a biopolitical tool designed to govern and regulate populations in a way that determines who may live and who must die. The governance and the management of the population, what Stephan Scheel terms as biopolitical bordering, depends on boundaries between residents and non-residents, citizens and non-citizens, and emigrants and immigrants. Drawing on Foucault’s biopolitics and Mbembe’s necropolitics, this paper argues that the concept of racism should be examined within the context of political discourses because it is intertwined with the colonial project, enslavement, and diaspora. This paper critically explores ethnic and racial injustices the Lhotshampa people experienced and the ways in which they negotiated and resisted such injustices in their resettlement processes, including before displacement, in refugee camps, and after the third-country resettlement. Critical examination of these issues helps shed light on the notion of racial difference that justifies dehumanization, discrimination, and racist attitudes against the Lhotshampa people. The study's findings are critical in promoting human rights, social justice, and the health and well-being of the Lhotshampa community in the context of trauma and stressors in their resettlement processes.

Keywords: lhotshampa people, bhutanese refugees, racism, dehumanization, social justice, biopower, necropower

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Authors: Karun K. Karki

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Globalization has intensified the transnational movement of people, mainly from the Global South to the Global North. In this context of transnationalism, migration is framed within the national interests required for economic prosperity. More specifically, the competition for the ‘best and the brightest of highly educated immigrants from around the world can be perceived as evidence that countries in the North are competing in the knowledge-based global economy. Canada is not an exception. Since the early 1970s, Canada has successfully admitted, on average, 200,000 to 280,000 immigrants annually for permanent residency, primarily for economic development, family reunification and humanitarian affairs. Among these three components, economic class immigrants are the highest priority in its immigration policy. Although Canada admits highly qualified immigrant professionals with the expectation of easily integrating them, many highly skilled immigrants are marginalized in the labour market due to a myriad of layered structural and institutional barriers that prevent them from working in the professions for which they were trained in their country of origin. More than 67% of highly skilled immigrants are more likely to be in jobs for which they are formally overqualified. The deteriorating employment situation of highly educated immigrants, particularly the immigrants of racialized groups, needs analytical scrutiny of the immigration policy of Canada. In this paper, author examine how the historical legacy of colonialism still continues in Canada’s immigration policymaking and how this legacy has impacted developing countries in the global South. Author argue that the Canadian immigration policy is based on the notion of exploiting/dominating smaller countries and immigrants from these countries. Such colonial policies have systematically ‘Othered’ immigrants based on their race, ethnicity, gender, culture, and linguistic characteristics. Recommendations are made to revisit contemporary immigration and settlement policies to effectively integrate immigrants into Canadian society.

Keywords: colonialism, Canadian immigration policy, racialized immigrants, skilled immigrants

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Authors: Prabesh Karki, Shyam Thapa Chettri, Bajarang Prasad Sah, Manoj Bhattarai, Sudeep Mishra

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Introduction: Frontal sinus is frequently described as the most difficult sinus to access surgically due to its proximity to the cribriform plate, orbit, and anterior ethmoid artery. Frontal sinus surgery requires a detailed understanding of the cellular structure and FSDP unique to each patient, making high-resolution CT scans an indispensable tool to assess the difficulty of planned sinus surgery. International Frontal Sinus Anatomy Classification (IFAC) was developed to provide a more precise nomenclature for cells in the frontal recess, classifying cells based on their anatomic origin. Objectives: To assess the proportion of frontal cell variants defined by IFAC, variation with respect to age and gender. Methods: 54 cases were enrolled after a detailed clinical history, thorough general and physical examinations, and CT a report ordered in a film. Assessment and tabulation of the presence of frontal cells according to the IFAC analyzed. The prevalence of each cell type was calculated, and data were entered in MS Excel and analyzed using Statistical Package for the Social Sciences (SPSS). Descriptive statistics and frequencies were defined for categorical and numerical variables. Frequency, percentage, the mean and standard deviation were calculated. Result: Among 54 patients, 30 (55.6%) were male and 24 (44.4%) were female. The patient enrolled ranged from 18 to 78 years. Majority33.3% (n=18) were in age group of >50 years.According to IFAC, Agger nasi cells (92.6%) were most common, whereas supraorbital ethmoidal cells were least common 16 (29.6%). Prevalence of other frontoethmoidal cells was SAC- 57.4%, SAFC- 38.9%, SBC- 74.1%, SBFC- 33.3%, FSC- 38.9% of 54 cases. Conclusion: IFAC is an international consensus document that describes an anatomically precise nomenclature for classifying frontoethmoidal cells' anatomy. This study has defined the prevalence, symmetry and reliability of frontoethmoidal cells as established by the IFAC system as in other parts of the world.

Keywords: frontal sinus, frontoethmoidal cells, international frontal sinus anatomy classification

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Authors: Rajesh Karki, Safal Bhattarai, Saket Adhikari

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Reliable and economic operation of power systems are becoming extremely challenging with large scale integration of renewable energy sources due to the intermittency and uncertainty associated with renewable power generation. It is, therefore, important to make a quantitative risk assessment and explore the potential resources to mitigate such risks. Probabilistic models for different energy storage systems (ESS), such as the flywheel energy storage system (FESS) and the compressed air energy storage (CAES) incorporating specific charge/discharge performance and failure characteristics suitable for probabilistic risk assessment in power system operation and planning are presented in this paper. The proposed methodology used in FESS modelling offers flexibility to accommodate different configurations of plant topology. It is perceived that CAES has a high potential for grid-scale application, and a hybrid approach is proposed, which embeds a Monte-Carlo simulation (MCS) method in an analytical technique to develop a suitable reliability model of the CAES. The proposed ESS models are applied to a test system to investigate the economic and reliability benefits of the energy storage technologies in system operation and planning, as well as to assess their contributions in facilitating wind integration during different operating scenarios. A comparative study considering various storage system topologies are also presented. The impacts of failure rates of the critical components of ESS on the expected state of charge (SOC) and the performance of the different types of ESS during operation are illustrated with selected studies on the test system. The paper also applies the proposed models on the test system to investigate the economic and reliability benefits of the different ESS technologies and to evaluate their contributions in facilitating wind integration during different operating scenarios and system configurations. The conclusions drawn from the study results provide valuable information to help policymakers, system planners, and operators in arriving at effective and efficient policies, investment decisions, and operating strategies for planning and operation of power systems with large penetrations of renewable energy sources.

Keywords: flywheel energy storage, compressed air energy storage, power system reliability, renewable energy, system planning, system operation

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Authors: Saddam Husain Dhobi, Bikrant Karki

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The main objective of this paper is save money, balance ecosystem of the terrestrial organism, control global warming, and enhancing the storage capacity of the battery with requiring weight and thinness by using Cyanobacteria in the battery. To fulfill this purpose of paper we can use different methods: Analysis, Biological, Chemistry, theoretical and Physics with some engineering design. Using this different method, we can produce the special type of battery that has the long life, high storage capacity, and clean environment, save money so on and by using the byproduct of Cyanobacteria i.e. glucose. Cyanobacteria are a special type of bacteria that produces different types of extracellular glucoses and oxygen with the help of little sunlight, water, and carbon dioxide and can survive in freshwater, marine and in the land as well. In this process, O₂ is more in the comparison to plant due to rapid growth rate of Cyanobacteria. The required materials are easily available in this process to produce glucose with the help of Cyanobacteria. Since CO₂, is greenhouse gas that causes the global warming? We can utilize this gas and save our ecological balance and the byproduct (glucose) C₆H₁₂O₆ can be utilized for raw material for the battery where as O₂ escape is utilized by living organism. The glucose produce by Cyanobateria goes on Krebs's Cycle or Citric Acid Cycle, in which glucose is complete, oxidizes and all the available energy from glucose molecule has been release in the form of electron and proton as energy. If we use a suitable anodes and cathodes, we can capture these electrons and protons to produce require electricity current with the help of byproduct of Cyanobacteria. According to "Virginia Tech Bio-battery" and "Sony" 13 enzymes and the air is used to produce nearly 24 electrons from a single glucose unit. In this output power of 0.8 mW/cm, current density of 6 mA/cm, and energy storage density of 596 Ah/kg. This last figure is impressive, at roughly 10 times the energy density of the lithium-ion batteries in your mobile devices. When we use Cyanobacteria in battery, we are able to reduce Carbon dioxide, Stop global warming, and enhancing the storage capacity of battery more than 10 times that of lithium battery, saving money, balancing ecology. In this way, we can produce energy from the Cyanobacteria and use it in battery for different benefits. In addition, due to the mass, size and easy cultivation, they are better to maintain the size of battery. Hence, we can use Cyanobacteria for the battery having suitable size, enhancing the storing capacity of battery, helping the environment, portability and so on.

Keywords: anode, byproduct, cathode, cyanobacteri, glucose, storage capacity

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