SERVICE QUALITY ATTRIBUTES AFFECTING THE SATISFACTION OF RAILWAY PASSENGERS OF SELECTIVE ROUTE IN SOUTHWESTERN PART OF BANGLADESH

With increased pace of urbanization and economic growth, attraction and dependency between different linking regions has also increased. Transportation have performed very crucial roles from very early accelerating the sharing of economic and development benefit of connecting spatial regions. Railway has been proved as a potential sector for drawing economic and development benefits for various countries. But less emphasis have been given in improvement of railway sector mainly in railway service in Bangladesh compare with road and which cause failed to draw proper economic benefit from the sector. This study has aimed to focus on the railway transportation sector and to develop a model defining the relationship between overall satisfaction and service quality attributes in a selective route from Khulna to Rajshahi in southwestern zone of Bangladesh so that it can reinforce further improvement process. Findings show that, overall service satisfaction depend on eight distinct service quality attributes. It implies the service with worst situation, overall satisfaction of service and need for priority improvement to support further orientation, addition and betterment of service to draw maximum economic and development benefit for those linking regions.Urbanization, Economic growth, Attraction, Linking region, Overall satisfaction

Enhancement of absorptance by ultrafast laser pulse shaping for efficient laser processing of thin polymers

Ultrashort-pulsed lasers have been used for high precision processing of a wide range of materials including dielectrics, semiconductors, metals, and polymers/polymer composites, enabling numerous applications ranging from micromachining, photonics to life sciences. However, there are challenges when applying this technology in the industry, which requires scale and throughput different from lab use. The goal of this research is to understand how ultrafast laser pulses interact with thin polymers/polymer composite materials and develop a method that is efficient for ultrafast laser processing of these materials. It is a common practice in industrial applications to run the laser at a high repetition rate and hence high average power. However, the heat accumulation under such processing conditions will deteriorate the processing quality, especially for polymers, which typically have a low melting temperature. An analytical solution for two-dimensional modeling of the temperature distribution has been presented and the solution is used to understand the effect of laser parameters on ultrafast laser processing of polypropylene (PP), which is an important polymer for both scientific and industrial applications. Laser cutting experiments are carried out on PP sheets to correlate with the theoretical calculation. This study shows that in laser cutting, the total energy absorbed in the material and the intensity are two important figures of merit to predict the cutting performance. It is found that heat accumulation can be avoided by a proper choice of the processing conditions and the optical properties (i.e. reflectance, transmittance, and absorptance) are important parameters to control processing with ultrafast lasers. To determine the reflectance, transmittance, and absorptance, time-resolved, single-shot measurements are performed in ultrafast laser interaction with polypropylene for a wide range of laser pulse energies. The absorptance during the ultrafast laser interaction with polymers is divided into the different linear and non-linear effective absorption channels and the absorption mechanism of ultrafast laser interaction with polymers in near-infrared wavelength are explained with a model that takes into account different effective absorption channels and suggests that the non-linear absorption originates from vibrational overtone/combination absorption. The enhancement of the absorptance has been investigated for efficiently processing thin polymers with ultrafast lasers by changing pulse duration. It is suggested from this study that the intense shorter pulse (167 fs) is more efficient for surface processing as most of the energy absorbed at the surface due to the strong nonlinear absorption, while a longer pulse (1000 fs) is more efficient for bulk processing for polymers. The results are useful for designing and controlling ultrafast laser processing of polymers and optimizing laser process parameters for the most efficient processing of polymers

The impact of the COVID-19 pandemic on the education of medical, dental and non-medical healthcare professionals in Bangladesh : findings and connotation

Lockdown measures in response to the COVID-19 pandemic had an appreciable impact on the education of all medical, dental, and non-medical healthcare professional (HCP) students. These included the closure of universities necessitating a rapid move to e-learning and new approaches to practical’s. However initially, there was a lack of knowledge and expertise regarding e-learning approaches and the affordability of internet bundles and equipment. We initially con-ducted two pilot studies to assess such current challenges, replaced by a two-stage approach including a full investigation involving 32 private and public universities during the early stages of the pandemic followed by a later study assessing the current environment brought about by the forced changes. Top challenges at the start of the pandemic included a lack of familiarity with e-learning approaches, cost of the internet, lack of IT equipment and the quality of the classes. Universities offered support to staff and students to a varying degree to address identified challenges. Since then, e-learning approaches have widened the possibilities for teaching and learning at convenient times. However, challenges remain. In conclusion, there were considerable challenges at the start of them pandemic. Several key issues have been addressed with hybrid learning here to stay. Remaining challenges include a lack of ICT equipment. However, new innovations will continue

Studying cellular and molecular interaction with two-photon microscopy

Advances in microscopy and fluorescent probes provide new insight into studying cellular and molecular interactions. Two-photon fluorescence microscopy is one of the most important recent inventions in cellular and molecular study. This technology enables noninvasive study at cellular and molecular levels in three dimensions with submicrometer resolution. Two-photon excitation of fluorophores results from the simultaneous absorption of two photons. This excitation process has a number of unique advantages, such as reduced specimen photodamage and enhanced penetration depth. In this study, we used our two-photon microscope to observe predatorial behavior of fast moving bacterivorous marine organism Cafeteria roenbergensis and quantify Mycobacterium phagosomal rupture in macrophages

Studying Cellular And Molecular Interaction With Two-Photon Fluorescence Microscopy

Advances in microscopy and fluorescent probes provide new insight into studying cellular and molecular interactions. Two-photon fluorescence microscopy is one of the most important recent inventions in cellular and molecular study. This technology enables noninvasive study at cellular and molecular levels in three dimensions with submicrometer resolution. Two-photon excitation of fluorophores results from the simultaneous absorption of two photons. This excitation process has a number of unique advantages, such as reduced specimen photodamage and enhanced penetration depth. In this study, we used our two-photon microscope to observe predatorial behavior of fast moving bacterivorous marine organism Cafeteria roenbergensis and quantify Mycobacterium phagosomal rupture in macrophages

Social Media Use During Social Gathering Among Youth: A Study on Moghbazar Area of Dhaka City

The rise of social media and continuous technological advances have had a significant impact on how people communicate. Social media sites include social networking sites like Facebook, Instagram, and WhatsApp, and any website that allows social interaction. Many studies have been conducted on the impact of social media, but this study is specifically based on the impact of social media on social gatherings in Dhaka. The primary objective of this study is to examine how the virtual world reshapes the way of social gathering. In this study, an online survey was administered to find out the level of engagement of social media during a social gathering. The researcher collected a total of 120 respondents using the purposive sampling method. Findings suggest that social media intensely affects social gatherings. Despite respondents' awareness of the decrease of face-to-face communication as a result of social media, more than 74 percent of respondents continue to use social media during a social gathering. Use of social media sites found to be harnessing the quality of conversation. While technology facilitates instant communication, it also harms regular interaction

Ammonia Volatilization Reduced by Combined Application of Biogas Slurry and Chemical Fertilizer in Maize–Wheat Rotation System in North China Plain

Digestate and biogas slurry (BS) are the byproduct of biogas engineering that could be used for elevating plant growth. However, the consequent emissions of ammonia from BS are considered a severe threat to the atmosphere. Herein, we conducted two consecutive field experiments with wheat–maize rotations to find out the optimum ratio of BS to combine with chemical fertilizer (CF) to reduce ammonia volatilization (AV) while keeping the stable crop yield. In maize season, 226.5 kg N/ha of CF was applied. In wheat season, 226.5 kg N/ha was applied at different ratios (100%, 80%, and 50%) between BS and CF. Our results found that the maximum yield of 6250 kg/ha was produced by CF, and this yield could be obtained through a combined application of 38% BS mixed with CF. Highest AV produced of 16.08 kg/ha by CF. BS treatments significantly reduced the emission from 18% to 32% in comparison to CF. The combined application of BS-CF produced the highest yield due to essential nutrients coming from both BS-CF. Subsequently, it reduced the AV depending on fertilizer type and fertilizer rate. An optimal ratio of 38% BS was recommended to produce the highest yield and lowest ammonia emissions. The application of BS together with different ratios of CF could be an alternative agricultural strategy to obtain desired crop yield and reduce AV in North China Plain (NCP)

Laser Raman Spectroscopy with Different Excitation Sources and Extension to Surface Enhanced Raman Spectroscopy

A dispersive Raman spectrometer was used with three different excitation sources (Argon-ion, He-Ne, and Diode lasers operating at 514.5 nm, 633 nm, and 782 nm, resp.). The system was employed to a variety of Raman active compounds. Many of the compounds exhibit very strong fluorescence while being excited with a laser emitting at UV-VIS region, hereby imposing severe limitation to the detection efficiency of the particular Raman system. The Raman system with variable excitation laser sources provided us with a desired flexibility toward the suppression of unwanted fluorescence signal. With this Raman system, we could detect and specify the different vibrational modes of various hazardous organic compounds and some typical dyes (both fluorescent and nonfluorescent). We then compared those results with the ones reported in literature and found the deviation within the range of ±2 cm−1, which indicates reasonable accuracy and usability of the Raman system. Then, the surface enhancement technique of Raman spectrum was employed to the present system. To this end, we used chemically prepared colloidal suspension of silver nanoparticles as substrate and Rhodamine 6G as probe. We could observe significant enhancement of Raman signal from Rhodamine 6G using the colloidal solution of silver nanoparticles the average magnitude of which is estimated to be 103