Investigation on the Chatter Vibration and Surface Texture in Vibration Assisted Micro-milling Process

Regenerative chatter is an unstable form of self-excited vibration in the machining process. It is one of the main obstacles which limit the productivity and the surface quality. This thesis investigates the effect of vibration assistance on high frequency regenerative chatter in the micro milling process. External vibration is applied on the Al-6061 workpiece in a range of frequencies and amplitudes using the piezoelectric actuators. The chatter vibration is monitored using the sound pressure signal measured by a microphone. The chatter with vibration assistance in 1-D (feed or normal direction) and 2-D is studied. The effect of the frequency and amplitude of the vibration assistance on chatter is analyzed. It is concluded from the experimental study that the vibration assistance is able to effectively attenuate the high frequency chatter in the micro milling process.Surface texturing is an innovative technique to generate patterns on the surface. These surfaces can be used for friction reduction in several applications such as internal combustion engines, micro-electrical- mechanical systems (MEMS), micro-fluids etc. Electric discharge texturing, laser texturing and photolithography are some of the finishing processes applied to the machined surface to create surface textures. However, this requires a long process which makes it costly and time consuming. This thesis focuses on surface texture generation by micro side milling with vibration assistance. External vibration is applied on the workpiece at the frequency and input voltage which can generate micron level amplitude. The machined surface profile is measured using a 3-D profilometer. Surface textures created with and without vibration assistance is compared. The effect of feed rate and different types of tools on surface texture is also studied.Mechanical & Aerospace Engineerin

Protected cultivation of horticultural crops in Nepal: Current practices and future needs

Protected cultivation infers the cultivation under guarded conditions or we can say simply, cultivation under a modified atmosphere or man-made micro-climatic conditions such as alteration in the CO2 concentration also use of different temperature levels on specific protected structures such as hoop houses, cold houses, shade houses, hot frames or hotbeds, hot-bed manures as well as high tunnels which are less costly as well and can be easily afforded by Nepalese farmers. Horticultural crops rely heavily on specific environmental conditions i.e., temperature, soil moisture, sunlight, and soil fertility. However, with climate change, weather patterns worldwide are shifting, significantly impacting horticultural crops directly and indirectly in the mid-hills as well as high-hills of Nepal. The people of the mountainous region are getting malnutrition due to the scarcity of food. By adapting the different climate-smart practices we can increase the productivity of the seasonal crop as well as the availability of off-season crops throughout the year which not only improves the malnutrition status of Nepalese people but also helps the country to lower the vulnerability towards climate change. This review highlights the common protected practices used in Nepal and their need in the future

Ayurvedic management of Retinitis Pigmentosa (Doshandha) - A Case Study

Retinitis pigmentosa (RP) is an inherited, degenerative eye disease that causes severe vision impairment due to the progressive degeneration of rod photoreceptor cells in retina. This form of retinal dystrophy manifests initial symptoms independentof age; thus, RP diagnosis occurs anywhere from early infancy to late adulthood. This primary pigmentary retinal dystrophy is a hereditary disorder predominantly affecting the rods more than the cones. The main classical triads of retinitis pigmentosa are arteriolar attenuation, Retinal bone spicule pigmentation and Waxy disc pallor. The main treatment of retinitis pigmentosa is by using Low vision aids (LVA) and Genetic counseling. As such a complete cure for retinitis pigmentosa is not present. So a treatment protocol has to be adopted that helps in at least the symptomatic relief. In Ayurveda, the signs and symptoms of this can be compared with the Lakshanas of Doshandha which is one among the Dristigata Roga. It is considered as a diseased condition in which sunset will obliterate the Dristi Mandala and makes the person blind at night time. During morning hours the rising sunrays will disperse the accumulated Dosas from Dristi to clear vision. This disease resembles Kaphajatimira in its pathogenesis, but the night blindness is the special feature. Since the disease is purely Kaphaja, a treatment attempt is planned in Kaphara and Brimhana line. The present paper discusses a case of retinitis pigmentosa and it’s Ayurvedic Treatment

Morpho-physiological and biochemical response of rice (Oryza sativa L.) to drought stress: A review

Global food shortages are caused mainly by drought, the primary driver of yield loss in agriculture worldwide. Drought stress negatively impacts the physiological and morphological characteristics of rice (Oryza sativa L.), limiting the plant productivity and hence the economy of global rice production. Physiological changes due to drought stress in rice include constrained cell division and elongation, stomatal closure, loss of turgor adjustment, reduced photosynthesis, and lower yields. Morphological changes include inhibition of seed germination, reduced tillers, early maturity, and reduced biomass. In addition, drought stress leads to a metabolic alteration by increasing the buildup of reactive oxygen species, reactive stress metabolites, antioxidative enzymes, and abscisic acid. Rice tends to combat drought through three major phenomena; tolerance, avoidance, and escape. Several mitigation techniques are introduced and adapted to combat drought stress which includes choosing drought-tolerant cultivars, planting early types, maintaining adequate moisture levels, conventional breeding, molecular maintenance, and creating variants with high-yielding characteristics. This review attempts to evaluate the various morpho-physiological responses of the rice plant to drought, along with drought stress reduction techniques

Ecology and Integrated Management of Ambrosia Beetles in Ornamental Nursery Trees

Ambrosia beetles (Coleoptera: Scolytidae) (AB) are small fungus-farming beetles that damage stressed nurseries trees. Under anaerobic stress, trees emit ethanol which is the primary cue for AB to locate suitable hosts. This study conducted experiments to help develop a push-pull management strategy and assess tree stress levels. First, two commercial wood dowel types – balsa wood (Ochroma pyramidale [Cav. ex Lam.]) and tulip poplar (Liriodendron tulipifera L.) – were evaluated as monitoring tools with ethanol. Second, repellent treatments were tested to determine efficacy against AB: cedarwood oil (CO2-derived), 2-butoxyethanol, 2-ethyl-1-hexanol, Beetle Guard (BG), and untreated control. Following this, ethanol-soaked flowering dogwood (Cornus florida L.) bolts were used to determine BG’s repellency against AB at increasing rates of ethanol emission and at an increasing distance from the repellent source. The BG product was effective in repellent experiments at increasing rates of ethanol at up to 2 m from the source. Third, two low-cost ethanol detectors (Alcohol Strip and Draeger PAC 8000) were used to quantify ethanol emissions from stressed trees root, bark, and twig tissue. Ethanol emission was verified using solid-phase microextraction gas chromatography-mass spectrometry (SPME-GC-MS). Ambrosia beetle attacks were assessed throughout the experiment. The overall thesis shows 1) balsa wooden dowel traps were promising for standardizing AB monitoring, (2) Beetle Guard may be useful in reducing AB attacks, and (3) low-cost field detectors can be used to assess ethanol emission from stressed trees. These results offer promising AB management strategies in ornamental nurseries that are more efficient and cost-efficient than current practices

The impact of climate change on insect pest biology and ecology: Implications for pest management strategies, crop production, and food security

The explosive expansion of the global population and technological progress has greatly influenced agriculture and food production. However, this progress is threatened by climate change, which unleashes a slew of issues like carbon dioxide (CO2) increases, frequent droughts, and temperature shifts that present a substantial obstacle to crop yields and food security. The ramifications of these climatic factors on insect pest biology and ecology are profound, given that these pests depend heavily on these factors. Since crop productivity is tightly connected to both insect pests and these climate variables, changes in these factors can significantly impact crop yields. Therefore, it is imperative to comprehend the impact of climate change on insect pests to manage them effectively and ensure sufficient food production. This review examines the climate change effect on insect pest biology and ecology and explores the potential use of modern pest monitoring technologies and prediction tools to devise effective pest management strategies to improve crop production and food security

Transition to professional practice: Perspectives of new nursing graduates of Nepal

Abstract Background Internationally, the transition from student nurse to practicing nurse is recognized as being the most stressful period. Yet very little is known about how new nursing graduates perceive this transition in Nepal. The study aimed to explore new nursing graduates’ perceptions of the transition to professional practice. Methods A qualitative descriptive methodology was used. In-depth semi-structured interviews were conducted with 10 purposively recruited participants from two private hospitals in Nepal. Data were analyzed using inductive thematic analysis. The Consolidated Criteria for Reporting Qualitative Research (COREQ) guidelines were used to report the findings of this study. Results New nursing graduates perceived the transition to professional practice as an intense experience. Inductive thematic analysis yielded four intrinsically linked themes that encompassed new nursing graduates’ transition experiences: ‘getting hit by reality’, ‘losing confidence’, ‘feeling unsupported’, and ‘gathering strengths.’ The theme ‘getting hit by reality’ included three sub-themes: ‘gap between theory and practice,’ ‘no protective shield,’ and ‘plethora of responsibilities’, which explains nurses’ initial encounter with real-world practice. The theme ‘losing confidence’ contained three sub-themes: ‘being fearful,’ ‘being ignored,’ and ‘being accused,’ which describes how nurses started losing confidence as they confronted the real side of the profession. The theme ‘feeling unsupported’ included two sub-themes: ‘left without guidance,’ and ‘limited support from seniors,’ which explains how nurses perceived their work environment. The theme ‘gathering strength’ contained two sub-themes: ‘reflecting’ and ‘asking for help,’ which describes how nurses coped with the challenges related to the transition. Conclusion To facilitate the transition to practice, educational institutions must impart to students a realistic understanding of the transition process, address the theory-practice gap, and collaborate with hospitals. Similarly, hospitals should have realistic expectations from new nurses, assign work according to their capabilities, and allow them sufficient time for role integration. Likewise, well-conceived detailed orientation, mentorship or preceptorship programs, and regular professional development programs are vital to easing the transition. Furthermore, establishing and maintaining a supportive work culture, which promotes equity, respect, and safety among employees, is crucial for positive transition experiences

Recurrent COVID-19 Waves and Lockdown: Impact on Daily Life and Mental Health of People in Nepal

Background. Lockdown is recognized as an effective measure in limiting the spread of coronavirus (COVID-19) throughout the world. However, recurrent COVID-19 infection and the extension of lockdown have threatened the livelihoods of people, mainly socioeconomic and mental health dimensions. Objective. The present study is aimed at identifying the impact of COVID-19 lockdown on the daily life and mental health of the general population of Nepal. Furthermore, the study identified the predictors of the mental health status of the people during COVID-19 lockdown. Methods. The study was conducted among 354 Nepalese people specifically the breadwinner of the family. Respondents completed the questionnaires related to the sociodemographic characteristics, COVID-19, and its impact on various aspects of life, including mental health via Depression, Anxiety, and Stress Scale-21 items (DASS-21). Data was collected through the web-based method, Google Forms questionnaire. Respondents were contacted through email and social networks (Facebook, Messenger, WhatsApp, and Viber) following a snowball approach. Data was analyzed using descriptive and inferential statistics. Logistic regression analysis was done to identify significant demographic, COVID-related, and socioeconomic factors associated with mental health outcomes. Results. Based on DASS-21 scores, the prevalence of depression, anxiety, and stress was 46.6% (mild: 22.3%, moderate: 16.7%, severe: 6.5%, and extremely severe: 1.1), 42.1% (mild: 10.2%, moderate: 18.6%, severe: 11.6%, and extremely severe: 1.7%), and 39% (mild: 16.7%, moderate: 12.7%, and severe: 9.6%), respectively. Various factors associated with COVID-19, its lockdown measures, and sociodemographic characteristics of the people were identified as the significant predictors of depression, anxiety, and stress among the general population of Nepal. Conclusion. The impact of COVID-19 lockdown on individuals’ work, income, education, living standard, lifestyle, and consequently mental health is significant. The study findings warrant the importance of understanding the impact of the COVID-19 pandemic on individuals’ all aspects of life and timely monitoring and appropriate intervention on risk groups to reduce the severity and chronicity of mental health problems

Study of microbial infection and associated antimicrobial resistance among patients admitted in intensive care unit of a tertiary care level hospital of Nepal

Background & objectives: In recent years, the rise in antibiotic resistance has posed challenges to the choice of empirical treatment for difficult cases. The objective of this study was to evaluate the prevalence of microbiological infections and the corresponding antibiotic resistance among patients admitted to the intensive care unit of a tertiary care hospital. Methods: The Microbiology laboratory received bacterial isolates from diverse clinical specimens originating from multiple Intensive Care Units (ICUs) for the purpose of culture and sensitivity testing. The identification of all species was conducted using both morphological and biochemical techniques, following established laboratory protocols. Additionally, the antibiotic susceptibility pattern was assessed by the utilization of disc diffusion methods. Results: The organisms were successfully isolated from 66.57% of the total 2920 samples collected. In 71.19% of the samples, a single organism was isolated, whereas in 28.8% of the samples, two or more organisms were found. Pseudomonas aeruginosa was the most often isolated bacterium, accounting for 38.17% of the total isolates. In the case of Pseudomonas aeruginosa, tobramycin has the most notable susceptibility rate at 94.2%, followed by meropenem at 93.93%, carbenicillin at 79.11%, and levofloxacin at 73.45%. The majority of commonly isolated pathogens have a high level of resistance to ampicillin, cephalexin, cefepime, and ciprofloxacin. Conclusions: The appropriate utilization of antibiotics in ICU plays a significant role in mitigating the development and spread of multi-drug resistance. Improved management of infections caused by resistant organisms in ICU necessitates the implementation of antibiotic policies and the establishment of robust surveillance systems

Isolation and Characterization of Potential Antibiotic-Producing Actinomycetes from Water and Soil Sediments of Different Regions of Nepal

Introduction. The actinomycetes are diversely distributed microorganisms in nature. The geographical diversity of Nepal is suitable for adaptation of various species of actinomycetes. The distribution of the actinomycetes is dependent upon the altitude and nature of the soil and water. Methods. A total of 22 water and soil samples were collected from different regions of Nepal and were processed. Different isolates were characterized by observing colony characteristics and microscopic characteristics. Screening of the antimicrobial property was based upon perpendicular line streaking and submerged-state fermentation for antibiotic production. Results. From the identification tool used, 12 were found to be Micromonospora, 9 were Nocardia, and 7 were Streptomyces. Out of total samples, 8 isolates of actinomycetes were tested effective against the tested bacteria by primary screening using the well diffusion method. Among the primarily screened, all isolates were subjected to submerged-state fermentation methods to produce crude extracts and 4 were found to be effective against the tested bacterial group. The actinomycetes identified from a water source showed better antimicrobial property towards the tested bacteria than the soil sample. Most isolates were found to be Micromonospora followed by Nocardia and Streptomyces with higher antimicrobial activities. Conclusion. The water source and soil sediments of Nepal provide suitable environments for actinomycetes towards obtaining a novel antimicrobial agent. The study of actinomycetes from various unexploited areas of Nepal is necessary. Thus, exploitation of various regions of Nepal for the discovery of an effective antimicrobial agent is helpful in providing a solution to the cost-effective therapy and action against antibiotic resistance