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SARS-CoV-2 or Covid-19, has emerged as the most serious public health threat of the contemporary age. More than 6.8 million individuals have died as a result of this infectious virus, which has infected about 673 million people. Coronavirus spread quickly across the world due to its infectious nature, resulting in a large number of deaths. In many ways, Covid-19 had an impact on nearly every nation in economic, social, cultural, political and other spheres. This paper is an attempt to identify major social determinants of Covid-19 worldwide with an extensive focus on Bangladesh society. The paper is primarily based on secondary sources like journal article, newspaper reports, research reports and validated website contents. The paper revealed that determinants of Covid-19 vary concerning the population, geographic location and other factors. In terms Bangladesh society, predominantly in urban areas, poverty is found to be a major determinant as well as impact of Covid-19. At the one hand, poor people tend to be more exposed to get infected by coronavirus; on another, Covid-19 induced lockdown in many ways crippled economic growth and triggered job loss and unemployment which contributed to increase poverty and marginality. Other social factors like social class, status, physical environment, health seeking behavior, and illiteracy are also found to be major determinants of Covid-19 infection.

Lifetimes of the upper states of excited oxygen atoms corresponding to transitions to the common lower state in the case of the emission lines around 777 nm and 844 nm have been estimated by measuring the line intensities as a function of the delay time between the Q-switching of the laser and the opening of the window of the ICCD. In the case of the emission line around 777 nm, resulting from the transitions from the three very closely spaced upper energy levels, 2s2 2p3 (4S0) 3p5P3 (777.194 nm), 2s2 2p3 (4S0) 3p5P2 (777.417 nm) and 2s2 2p3 (4S0) 3p5P1 (777.539 nm) to the common lower energy level 2s2 2p3 (4S0) 3s5S2, the lifetime was measured to be 253 ns. Similarly, in the case of the emission-line around 844 nm, resulting from the transitions from the three very closely spaced upper energy levels 2s2 2p3 (4S0) 3p3P0 (844.625 nm), 2s2 2p3 (4S0) 3p3P2 (844.636 nm) and 2s2 2p3 (4S0) 3p3P1 (844.676 nm) to the common lower energy level 2p3 (4S0) 3s3S1, the lifetime was measured to be 278 ns by this technique. The measured lifetimes in our experiment, for both 777 nm and 844 nm atomic transition lines of oxygen (O), are almost nine times higher than the theoretical value. Self-absorption and radiation trapping are possible mechanisms responsible for the mismatch between measured and intrinsic lifetimes. Last but not least, utilizing the TR-LIBS technique is yet another incredible application to estimate the prolonged lifetime of closely spaced excited states of an atom in the presence of self-absorption and radiation trapping. The average plasma cooling temperature (excitation temperature) lifetime was found to be 1183 ns, which is compatible with the previously reported values. J. Bangladesh Acad. Sci. 46(2); 175-183: December 2022

SARS-CoV-2 or COVID-19, has emerged as the most serious public health threat of the contemporary age. More than 4.2 million individuals died as a result of this infectious virus, which has infected about 200 million people. Coronavirus spread quickly across the world due to its infectious nature, resulting in a large number of deaths. In many ways, COVID-19 had an impact on nearly every nation in economic, social, cultural, political, and other spheres. The study aims to find out the portrayal of Intimate Partner Violence (IPV) in popular English newspapers in Bangladesh. Data were collected from the 12 most-read English dailies that published news on IPV all over the country. The study used a summative approach of the qualitative content analysis method as formulated by Bengtsson (2016). Findings show that the frequency of published news on IPV considerably increased amid COVID-19 induced lockdown in Bangladesh. The causes of such incidents go back to deep-rooted patriarchal norms, gender roles and the powerlessness of women. Many incidents occurred during lockdown that, as victims reported, were triggered by shocks like sudden joblessness, chronic stress, abject poverty, etc. caused by the pandemic. Such violence often affected women’s physical, mental and reproductive health. Many incidents like stabbing to death, killing with the home weapon, and physical abuse became national headings amid lockdown. The study suggests undertaking special protection measures for women in any such future event. Awareness and cooperation of people along with appropriate policies can be major steps towards combating the impacts of COVID-19.

Rural conflicts are becoming more intensive in recent years, predominantly political conflicts are increasing in Bangladesh. Recently, few clashes in Brahmanbaria districts gained widespread momentum in the whole country. According to a report, a total of 1437 clashes occurred in the last 2 years, which caused 151 death and many injuries. Some conflicts were assumed to be clan-based (ghosti) and strengthened by the aim of establishing supremacy in the area by local elites. No study has been conducted on this issue previously concerning the causes and consequences of this frequent violence. So, the study aims to explore the nature and pattern of frequent clashes and provide some recommendations based on the findings. The present study adopted qualitative methods. Primary data were collected from five selected villages from Sarail Upazila where conflicts broke out the most. Initially, the researchers used the participant observation method for understanding the issue and locating the respondents for the interview. Then, data were collected using in-depth interviews, Key informant interviews, and Focus group discussion methods. Findings of the study suggest that conflicts in Brahmanbaria are a deep-rooted problem. There are no specific causes or patterns of these clashes, yet the participation of people in these clashes increasing. Conflict breaks out for a minimal matter, later local clans and villagers join in the mob. Often, these clashes end with mutual agreement mediated by the village headman, but the animosity between or among groups remains the same which causes further clashes.

Treated wastewater can promote to minimizing the water stress in agricultural field due to the scarcity of irrigation water. The aim of the experiment was to determine the toxic metallic contamination for wastewater irrigation in the investigated area. Analytical techniques were used to determine quality parameter and ionic constituents. Samples were considerably alkaline (pH = 7.55 to 10.05). As for recommended TDS, samples were categorizing as freshwater (60%) and brackish water (40%). Electrical Conductivity (EC) and Sodium Absorption Ratio (SAR) express the salinity and alkalinity indicates the classes C4S1, C3S1 & C2S1. Soluble sodium percentage (SSP) categorized in different grade in samples. Regarding Hardness (HT), samples were rank as very hard, hard, and moderately hard. Upon analysis, all HCO3 was extremely hazardous, noxious for watering to plants and 56% samples of Cl, 92% of Cu and all sample of Cd were exceeded the limit thus risky for irrigation usage but zinc and iron have no effect on irrigation. Finally, the results revealed that all samples except few under test were unsuitable for irrigation due to having toxic metals such as Cu, Mn, Cd, HCO3, and Cl. From the above discussion, we concluded that most of the parameters like Cu, Mn, Cd, HCO3, and Cl were exceeded the maximum acceptable level and wastewater must be treated to remove all toxic elements before irrigation into the field. Moreover, this wastewater is a great value to reducing the water stress in farm level due to limited irrigation water.

Background Climate change and increasing demand in non-agricultural sectors profoundly affect the availability and quality of water resources for irrigated agriculture. The FAO AquaCrop simulation model provides a sound theoretical framework to investigate crop yield response to environmental stress. This model has successfully simulated crop growth and yield as influenced by varying soil moisture environments for crops. Integrating crop models that simulate the effects of water on crop yield with targeted experimentation can facilitate the development of irrigation strategies for high yield procurement and improving farm level water management and water use efficiency (WUE) under climatic condition of District Hyderabad, Sindh, Pakistan. Results This study was based on completely randomized block design with three treatments including T1 (30% soil moisture depletion), T2 (50% soil moisture depletion) and T3 (70% soil moisture depletion) with three replicates. In order to determine the crop water requirements under desired treatments, the gypsum blocks were used for computing the daily soil moisture depletion. The result shows that total volume of water applied to crop under T1, T2 and T3 was 9689, 5200 and 2045 m3 ha−1, respectively. As a result, the grain yield under T1, T2 and T3 was 13.2, 12.1 and 14.3 t ha−1, respectively. These results advocate that total yield of crop under T1 and T2 was less as compared to T3. The T3 gave higher yield and WUE compared than other treatments. On the other hand, results revealed that the simulated sunflower yields showed a good agreement with their measured under T3. The simulated grain yield was 15.5 t ha−1, while the measured yield varied from 12.1 to 14.3 t ha−1. This study suggested that WUE under T3 was more as compared to T1 and T2. The results showed that the T3 gave the highest crop yield in relation to WUE and optimize yield of sunflower crop under water scarcity. Conclusion The Aquacrop model could very well predict crop yield and WUE at T3 under experiential region for sunflower production.

Bihari community has been living in Bangladesh since 1947, after being forced to migrate from various regions of India. Owing to religious differences, the Bihari community was expelled for communal riot from their homeland. Subsequently, they moved to their ideological home propagated by two-nation theory. Bangladesh joined Pakistan as federal state after partition which made Muslims of India, including the Biharis, thought that Bangladesh was also their ideological home. Having a distinct language and culture, the Bihari community could not be able to assimilate into the society of Bangladesh. They had to remain stranded and stuck in between two cultures outside of their home. However, they were given citizenship by the Government of Bangladesh, but still the debate of them being ‘others’ still on. This study aims to trace out the origin of the Bihari community in Bangladesh and to find out their current socio-cultural condition. To reveal their socio-cultural condition, this study used qualitative method. Primary data were collected through semi-structured interviews in two Bihari settlements (camps) at Dhaka city. This study suggests that Bihari identity has been very problematic and still debatable. Even after 70 years, many Biharis have retained their distinct socio-cultural practices, while other chose assimilation. Nevertheless, their deplorable condition has been intensified by abject poverty, social exclusion and lack of entitlements to services affecting their socio-cultural condition.

The advent of new media can change the world more quickly than the old media. We are living in the world in which the media take part in daily life. New technology brings blessing to those who adopt compare to those who are not willing to adopt or passing through the digital divide. Students use new technologies and social media for various purpose but now social media is used as a platform of business. For this article, this research has covered quantitative research method and the sample was divided by 700 students in two different countries, the questionnaire was used as a research tool. Most of the students of developing countries in the world is facing ‘’ Digital Divide’’ which forces people to depend on old media such as television contains audio and visual content which is undergoing considerable change that creates obstacle to those people are living with ‘’ Digital Divide’’ as consequence transforming the rural lives differently due to old media. The purpose is to determine if there is a significant difference in students influence on social media and television advertisements. The major contribution of this paper is new (social media) and old technologies (television) to what extent they influenced by those advertisements. A study conducted between Turkish Republic of Northern Cyprus (urban) and Bangladesh (rural) at analyzing the influence of digital divide of country-level factors, such as gender, technological infrastructure, income which would be provided to identify that by adopting of new media and old technology.

Background Tomatoes are now one of the most popular nutrient-dense vegetables in terms of acreage, production, yield, commercial use, and consumption that add to the Bangladesh economy and ultimately reduce poverty. With this view, a lab investigation was carried out to analyze the effects of tomato (Sofol and Roma VF) verities on different post-harvest managements to extend shelf life as well as reduce post-harvest losses. Results This study confirmed that the fruit quality attributes (color, firmness, weight loss, chilling injury, total soluble solids, pH, disease incidence, disease severity, and dry matter content) were increased whereas moisture content, vitamin C, and titratable acidity decreased with the increases in storage duration. The high quality attributes such as color, firmness, weight loss, chilling injury, total soluble solids, pH, disease incidence, disease severity, and dry matter content increased, whereas moisture content, vitamin C and titratable acidity decrease of tomato were observed in Roma VF while Sofol variety had high weight loss, moisture content, titratable acidity, and vitamin C. Moreover, the highest shelf life (17 days) was recorded in Sofol than Roma VF (15 days). On the 16th day of storage, maximum disease severity (41%) and disease incidence (71%) were observed at an earthen cooling pot, whereas a significant reduction in disease severity (1%) and disease incidence (8%) were recorded in tomatoes stored at 10oC temperature. Weight loss was the lowest (4%) in Sofol when kept at unperforated low-density polyethylene (LDPL) plastic bag as compared to Roma VF treatment (11%). Considering the physiological process, held at the low temperature (10 °C and 15 °C) and increased shelf life as well as reduced the diseases of tomatoes. Conclusions The investigator concluded that the findings of this study will be helpful with specific regard to long and medium-term storage, quality control, transportation, and advertising, and will also be beneficial to tomato growers of Bangladesh.

Background No-tillage is considered as a promising alternative for conventional farming by saving energy input and time, reducing groundwater pollution, and counteracting soil erosion and losses of soil-organic matter. Therefore, this study was carried out in north-eastern Sylhet of Bangladesh during the period of 2015–2016 to evaluate the multiple techniques of implementation in order to find a practically appropriate way to apply biochar. Results In this study, successfully applied of biochar and glyphosate in holes with seeds and consisted of one control (pure soil), glyphosate control, biochar control, and four glyphosate treatments with 1, 2.5, 5, and 10% biochar addition. The Gly + ch1% and Gly + ch2.5% treatments demonstrated a better emergence rate than all treatments, and at the end of the emergence, they reached more than 95%. There was no important distinction found among all the treatments in the event of shooting fresh and dry biomass. Biochar amendment treatments did not show any influence on shoot fresh biomass compared to glyphosate control and biochar 5% treatment, respectively. Gly + ch2.5% treatment showed slightly better performance than all the other treatments. The similar performance was shown in case of shoot dry weight. In case of root fresh weight, there was only a significant different observed between Gly + ch1% and Gly + ch10%. However, Gly + ch1% treatment revealed slightly higher root fresh weight compared to all the other treatments. Considering the results of the germination percentage and root morphology, it could be suggested that lower rate of biochar application showed better performance on root length and development. Conclusions It could be concluded that glyphosate application has mitigation effect to absorb herbicidal residues. For successful introduction of biochar application in agriculture, field acts as a huge amount of carbon sink and has also a positive effect to mitigate climate change.

Plant triterpenoids are major sources of nutraceuticals that provide many health benefits to humans. Lupeol is one of the pentacyclic dietary triterpenoids commonly found in many fruits and vegetables, which is highly investigated for its pharmacological effect and benefit to human health.This systematic review critically discussed the potential pharmacological benefits of lupeol and its derivatives as evidenced by various cellular and animal model studies. To gain insight into the pharmacological effects of lupeol, the network pharmacological approach is applied. Pharmacokinetics and recent developments in nanotechnology-based approaches to targeted delivery of lupeol along with its safety use are also discussed.This study is dependent on the systematic and non-exhaustive literature survey for related research articles, papers, and books on the chemistry, pharmacological benefits, pharmacokinetics, and safety of lupeol published between 2011 and 2021. For online materials, the popular academic search engines viz. Google Scholar, PubMed, Science Direct, Scopus, ResearchGate, Springer, as well as official websites were explored with selected keywords.Lupeol has shown promising benefits in the management of cancer and many other human diseases such as diabetes, obesity, cardiovascular diseases, kidney and liver problems, skin diseases, and neurological disorders. The pharmacological effects of lupeol primarily rely on its capacity to revitalize the cellular antioxidant, anti-inflammatory and anti-apoptotic mechanisms. Network pharmacological approach revealed some prospective molecular targets and pathways and presented some significant information that could help explain the pharmacological effects of lupeol and its derivatives. Despite significant progress in molecular pharmacology, the clinical application of lupeol is limited due to poor bioavailability and insufficient knowledge on its mode of action. Structural modification and nanotechnology-guided targeted delivery of lupeol improve the bioavailability and bioactivity of lupeol.The pentacyclic triterpene lupeol possesses numerous human health-benefiting properties. This review updates current knowledge and critically discusses the pharmacological effects and potential applications of lupeol and its derivatives in human health and diseases. Future studies are needed to evaluate the efficacies of lupeol and its derivatives in the management and pathobiology of human diseases.

The huge excrement quantity from the increasing large-scale livestock stressed the ecological, environmental deterioration. As a major benefit for handling livestock manure, the slurry of biogas (BS) is developed during the production of biogas that might increase plant productivity. However, nitrous oxide (N

Urdu-speaking Bihari community was displaced from various regions of India initially after the partition and once again after the independence of Bangladesh. As they are considered Pakistani in a primordial sense, lots of attempts were made to send them back to Pakistan, their ideological home. But due to diplomatic failure and several other reasons, only a few people could repatriate, left majority behind. But they could never assimilate here. As a result, their identity crisis began. The government of Bangladesh, considering their despondent condition, declared them as citizens of Bangladesh. But still there remain difficulties in achieving full functioning citizenship status since they have not fully integrated into the society as a whole. This study aims to reveal the current condition of the Bihari identity crisis and the degree of assimilation to the Bengali society and culture. By adopting a qualitative approach, it took stratified sampling method to collect data. Data were collected through semi-structured interviews. 20 people were being interviewed living inside the Geneva camp and outside. The analysis of data revealed that the citizenship status was given for the political purpose, not actually intended for their rehabilitation or well-being; that the citizenship status doesn’t help to eradicate their fear of being treated as “others” or a minority group. Their assimilation to Bangladeshi society and culture, however, deepened very recently. A sense of communal harmony prevails between Bengalis and Biharis, except for a few exemptions. Besides, though both the issues are similar in type, the Bihari has never gained widespread attention like the Rohingya people usually get from the government as well as the international bodies

Time-resolved, single-shot measurements are performed to determine the reflectance, transmittance, and absorptance in ultrafast laser interaction with polypropylene for a wide range of laser pulse energies. An ellipsoidal mirror is used to collect the majority of the reflected light, enabling the detection of plasma emission starting at about 40 ns after the incident pulse. The measured transmittance is explained by a model that takes into account different effective absorption channels, and the non-linear absorption coefficient is estimated, which suggests that the non-linear absorption originates from the two-step or two-photon absorption through overtone. The results are useful for selecting laser parameters in the processing of polymeric materials.

Polymers are important materials for both industrial and scientific applications. However, it is challenging to efficiently process polymers with an ultrafast laser due to their low melting point, high bandgap, and different absorption mechanics with different laser parameters. It is common practice in industries to use different kinds of lasers and, therefore, different laser parameters, such as pulse duration, wavelength, pulse energy, etc. In particular, the effect of pulse duration during ultrafast laser interaction with polymers is significant as the absorption mechanism can be different with different pulse durations. In this study, the effect of pulse duration is investigated during the ultrafast laser interaction with transparent polypropylene (TPP), which is an important polymeric material widely used in many industrial applications. This study is based on the experimental measurement of the optical properties of TPP during ultrafast interaction, where optical properties, i.e., reflectance, transmittance, and absorptance, are determined by performing time-resolved measurements in single-pulse configurations. This experiment is carried out by collecting in situ data of the reflection and transmission of each laser pulse in an ellipsoidal reflector-based experimental setup, which enables the collection of both specular and diffusive reflection with nearly full coverage, and absorption is calculated from the experimental results. It is found that TPP undergoes a dramatic morphological change with different pulse durations ranging from 167 fs to 1 ps, which is correlated with the change of optical properties during the ultrafast laser interaction with TPP for different pulse durations. This result will be useful for controlling the processing of polymers with ultrafast lasers for industrial applications.

Background Garlic (Allium sativum L.) has been used as a medicine throughout ancient and modern history; it has been taken to prevent and treat a wide range of conditions and diseases. In Bangladesh, the demand for garlic increases day by day, but on the other hand, due to a shortage of land, production of garlic is not up to the mark. However, to solve the problem, a pot culture experiment was conducted at the net house of the Department of Agricultural Chemistry, Bangladesh Agricultural University, Mymensingh during the period of November 2007 to March 2008 to examine the effect of potassium (K) on the growth, yield, nutrient content, and its uptake by garlic. Results In this study, six levels of K viz. 0, 100, 125, 150, 175, 200, 250 kg ha−1 were used as treatments. All the parameters, i.e., plant height, number of leaves plant−1, fresh and dry weights of leaves (g plant−1), fresh and dry weights of bulb (g plant−1), bulb diameter, and number of cloves bulb−1 significantly varied due to different doses of K application. The maximum total yield and size of garlic bulb were obtained with potassium application at 200 kg ha−1. Potassium at 200 kg ha−1 produced the highest fresh and dry weights of bulbs and leaves, diameter, moisture content, number of cloves, and yield as compared to the other treatments. The uptake of nutrients like N, P, K, S, Ca, Mg, B, and Na significantly varied due to the application of different doses of K. The highest contents and nutrient uptake of N, P, K, S, Ca, Mg, B, and Na were found with potassium application at 200 kg ha−1. Conclusions The overall results suggested that the yield of garlic increased with increasing potassium fertilizer, where K application at 200 kg ha−1 is suitable for obtaining maximum yield.

Material processing is a type of laser applications that requires good control of lasermatter interaction under the condition of high average laser power and high peak intensity. In this talk, I will present examples of applying optical sensing in ultrafast laser processing of polymetric materials to identify optimal processing parameter and achieve closed-loop operation.

Biochar application is considered an effective method of reducing nitrous oxide (N

Ultrafast lasers have been used for high-precision processing of a wide range of materials, including dielectrics, semiconductors, metals and polymer composites, enabling numerous applications ranging from micromachining to photonics and life sciences. To make ultrafast laser materials processing compatible with the scale and throughput needed for industrial use, it is a common practice to run the laser at a high repetition rate and hence high average power. However, heat accumulation under such processing conditions will deteriorate the processing quality, especially for polymers, which typically have a low melting temperature. In this paper, an analytical solution to a transient, two-dimensional thermal model is developed using Duhamel's theorem and the Hankel transform. This solution is used to understand the effect of laser parameters on ultrafast laser processing of polypropylene (PP). 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. Heat accumulation is observed at low scanning speeds and high repetition rates, leading to significant heat-affected zone and even burning of the material, which is supported by experimental data and modelling results. It is found that heat accumulation can be avoided by a proper choice of the processing condition.

We report on the experimental and theoretical studies of ultrafast laser-induced optical breakdown on the surface of fused silica to elucidate the mechanism of damage formation and sub-optical-cycle dynamics in material processing using single and a burst of two femtosecond laser pulses. Ionization pathways, including photo-ionization (PI) and avalanche ionization (AI), are investigated by using single-beam and double-beam laser damage threshold measurements, which are used to analyze electron dynamics and extract the avalanche coefficient. The relationship between damage size and laser fluence is interpreted as a result of a combination of PI and AI. Electrical field rather than laser intensity is the fundamental influential factor in PI, and AI is found to play a significant role in creating the free electron density needed for optical breakdown. These findings are verified by a double-pulse delay-scan experiment where two cross-polarized pulses are used to induce damage with delay within a few optical cycles. Variation of the damage diameter is observed within one optical cycle, which is explained by the periodic change of polarization in the combined electric field. This finding shows the potential of controlling laser induced damage by tuning the temporal overlap of a burst of ultrashort laser pulses.

The huge excrement quantity from the increasing large-scale livestock stressed the ecological, environmental deterioration. As a major benefit for handling livestock manure, the slurry of biogas (BS) is developed during the production of biogas that might increase plant productivity. However, nitrous oxide (N2O) emissions from BS are considered a significant danger to the environment due to global warming potential. Furthermore, applying different proportions of BS combined with chemical fertilizer (CF) on N2O productions in the North China Plain (NCP) remains unclear. Herein, two sequential field trials were performed by maize-wheat rotations to substitute the CF by BS and reduce N2O emissions while keeping the crop yield stable. Four treatments were conducted, including T1, T3, T6, and CK. A total of 226.5 kg N ha−1 used in the maize-wheat rotation system. Additionally, different ratios of BS (100%, 80%, and 50%) combined with CF were used in wheat season in the tillering stage. Results showed integrated applications of BS with CF have potential for reducing N2O emission. Our findings showed that the maximum grain yield of CF was 6250 kg ha−1, which might be achieved by applying 38% BS and 62% of CF. This ratio yielded 1.03 kg ha−1 N2O emissions, which was 15% lesser than the N2O emission of CK, 1.21 kg ha−1. Considering whole growing period of wheat biogas treatments significantly reduced the cumulative N2O emissions from 17% to 26% compared to CF. To achieve maximum yield and minimum N2O emissions, an optimum 38% BS ratio has been suggested. The integrated use of BS and CF provided the greatest grain yield because of necessary nutrients provided by both slurry and CF. Consequently, N2O emissions reduced based on frequency and type of fertilizer. In conclusion, 38% ratio of BS combined with 62% CF would be a suitable approach to mitigate N2O emission and simultaneously increase crop yield in NCP.

Polymers were one of the first materials to be processed by ultrafast lasers. However, the nature of absorption for near-infrared laser beams is not fully understood, and therefore it remains challenging to process polymeric materials with high energy efficiency. In this study, the pulse-to-pulse evolution of optical properties (reflectance, transmittance, and absorptance) of polypropylene (PP), which is an important polymeric material widely used in many industrial applications, is determined by performing time-resolved measurements for a wide range of pulse energies. The goal is to differentiate between linear and nonlinear absorption in different laser-matter interaction regimes and select the processing condition that yields the highest energy efficiency. The experiment is performed by recording the reflection and transmission of each laser pulse in an ellipsoidal mirror-based setup, which enables the collection of scattering reflection with nearly full coverage. Absorption is calculated from the experimental data, and a model consisting of linear and nonlinear absorption is used to analyze the results. It is found that PP undergoes a dramatic morphological change from pulse to pulse, which is accompanied by changes in optical properties, that is, the tuning of the laser condition to fully utilize the laser energy. Their results could help increase energy efficiency in ultrashort-pulsed laser processing of polymers toward the high-throughput operation.

In the processing of laser materials, the scanning area is limited by the extent to which the laser focus can be maintained within a plane. In order to increase the processing area, one has to enlarge the size of the laser focal spot, and, therefore, reduce the peak intensity and spatial resolution. In this paper, the authors report on a method that extends the processing area by controlling the wavefront of a laser beam using adaptive optics. By adding Zernike modes to the laser beam wavefront, the axial (along the beam propagation direction) location of the focal spot can be tuned within a range larger than the confocal length (two times the Rayleigh length), while the lateral spot size (and, thus, peak intensity and resolution) is maintained throughout the tuning range. A wave propagation model that simulates the propagation of a wavefront-controlled beam is used to compare with the experimental results, which are also confirmed by Zemax calculation. Laser trepanning of circular holes with consistent size on a wide polypropylene sheet is demonstrated. This work shows the potential of tailoring the phase of a laser beam for improving the accuracy and throughput in large-area laser processing of materials.

Biochar application is considered an effective method of reducing nitrous oxide (N2O) emissions in soil. However, the mechanism and temporal effect of different doses of biochar on N2O emissions is still obscure. Here, we conducted a two-year field experiment to test the effects of different input amounts and frequencies of biochar on soil N2O emissions in North China. Biochar was applied in six different treatments in a winter wheat and summer maize rotation system: applications of 0 t/ha biochar (C0), 2.25 t/ha biochar (C1), 4.5 t/ha biochar (C2), 9 t/ha biochar (C3), and 13.5 t/ha biochar (C4) each year, and a single application of 13.5 t/ha biochar (CS) in the first year. The results showed that biochar could inhibit N2O emissions, reaching 20.6% to 60.1% in the wheat season and 18.1% to 39.4% in the maize season. The inhibitory effect of biochar on soil N2O emissions was dependent on amount and time. C3 had the best results in the wheat season, although its inhibitory effect in the maize season was not as good relative to C4 due to the lower biochar application. In addition, CS significantly reduced (27.7%) the cumulative N2O emissions in the first year, although the inhibitory effect disappeared in the second year. Biochar increased the nosZ gene copy numbers and promoted a reduction of N2O in the soil via the denitrification process. In conclusion, the inhibition of N2O emissions during denitrification is an important factor for reducing soil N2O emissions by biochar, and the inhibition of biochar is influenced by the input amount and time.

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&ndash, 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).

Material processing by ultrafast lasers is an attractive technology for high-precision fabrication, such as cutting, drilling, and surface modification, of a wide range of material, including dielectrics, semiconductor, metals, and polymer composites. However, it is still challenging to apply ultrafast laser processing in many applications because some key processes, such as absorption and heat accumulation, are not fully understood, especially for polymeric materials, which have a low melting temperature and, therefore, are more vulnerable to thermal damage. In this study, an analytical solution to a transient, two-dimensional thermal model is derived using Duhamel's theorem and Hankel’s transform method to understand the effect of laser parameters during ultrafast laser interactions with polypropylene (PP), which is a material widely used in many industrial applications. To correlate with theoretical calculation, laser cutting experiments are carried out on PP sheets. This study found that the total energy absorbed in the material and the laser intensity are two important factors to estimate the laser processing performance. In addition, time-resolved measurements are performed by using fast photodiodes and an oscilloscope to understand the dynamics of ultrafast laser interactions during the laser cutting process. Transmitted and reflected signals are monitored and analyzed to extract information on nonlinearity and the absorption coefficient.

The authors report on the theoretical and experimental studies of laser-induced optical breakdown on the surface of fused silica to elucidate the influence of time delay and spatial separation between two ultrashort pulses on the position and size of the modification. Carriers involved in the damage formation including free electrons in the conduction band and self-trapped excitons (STEs) are investigated. The relationship between damage morphology and time delay shows that the seeding carriers (free electrons and STEs) generated from the first pulse are found to play a significant role for the second pulse—which is temporally and spatially separated from the first pulse—in creating the critical electron density needed for an optical breakdown. Consequently, processing outcomes, such as accuracy (position of the hole) and resolution (size of the hole), depend on the interplay of various laser-induced physics that can be tailored for specific goals. As a demonstration, laser lithography with resolution below the diffraction limit is achieved by exploiting multipulse induced physics. This work is a step toward repeatable laser processing of dielectrics beyond the diffraction limit and provides insights into ultrafast laser-matter interaction under the condition of an extremely high pulse repetition rate.

Segment display is very important in displaying numeric data. Although matrix display can be used to show any number with better font but it has some major disadvantages compared to segment display. Matrix display uses scanning techniques to show something, this technique is complex to implement and needs more memory. Here, a 20-segment display is proposed which can show numbers and mathematical symbols of 14 different languages. Also a decoder circuit is proposed which takes BCD input and generates output binary combination for 20-segment display of selected language. Finally a prototype of 20-segment display is implemented by LED's and the decoder circuit is implemented in FPGA. The system is checked for 14 different languages and some mathematical symbols.

For those who have lost the ability to move their hand, going through repetitious motions with the assistance of a therapist is the main method of recovery. We have been developed a robotic assistive device to rehabilitate the hand motions in place of the traditional therapy. The developed assistive device (RAD-HR) is comprised of four degrees of freedom enabling basic movements, hand function, and assists in supporting the hand during rehabilitation. We used a nonlinear computed torque control technique to control the RAD-HR. The accuracy of the controller was evaluated in simulations (MATLAB/Simulink environment). To see the robustness of the controller external disturbance as modelling uncertainty (±10% of joint torques) were added in each joints., {"references":["D. Mozaffarian, E. J. Benjamin, A. S. Go, D. K. Arnett, M. J. Blaha, M. Cushman, S. R. Das, S. de Ferranti, J. P. Després, H. J. Fullerton, and V. J. Howard, \"Heart Disease and Stroke Statistics—2016 Update A Report from the American Heart Association,\" Circulation, CIR-0000000000000350, 2015.","\"Paralysis,\" Stroke.org, 2014. (Online). Available at: http://www.stroke.org/we-can-help/survivors/stroke-recovery/post-stroke-conditions/physical/paralysis. (Accessed: 06-Mar-2016).","S. Masiero, A. Celia, G. Rosati, and M. Armani, \"Robotic-assisted rehabilitation of the upper limb after acute stroke,\" Archives of physical medicine and rehabilitation, vol. 88, no. 2, pp. 142-9, 2007.","P. S. Lum, C.G. Burgar, P. C. Shor, M. Majmundar, and M. Van der Loos, \"Robot-Assisted Movement Training Compared with Conventional Therapy Techniques for the Rehabilitation of Upper-Limb Motor Function After Stroke,\" Archives of Physical Medicine and Rehabilitation, vol. 83, no. 7, pp. 952-959, 2002.","G. R. Romer, H. J. Stuyt, and A. Peters, \"Cost-savings and economic benefits due to the assistive robotic manipulator (ARM),\" in 9th International Conference on Rehabilitation Robotics, ICORR, 2005, pp. 201-204.","A.D. Winter, Biomechanics and Motor Control of Human Movements, 2nd ed., University of Waterloo Press, Canada, 1992.","J. J. Craig, Introduction to Robotics Mechanics and Control, 3rd ed.: Pearson Prentice Hall, 2004.","N. P. Hamilton, Kinesiology: Scientific basis of human motion. Brown & Benchmark, 2011.","D. J. Magee, J. E. Zachazewski, and W. S. Quillen, Pathology and intervention in musculoskeletal rehabilitation. Elsevier Health Sciences, 2008.\n[10]\tM H. Rahman, M. Saad., J-P Kenné, and P. S. Archambault (2013). \"Control of an Exoskeleton Robot Arm with Sliding Mode Exponential Reaching Law.\" International Journal of Control, Automation, and Systems ,201, vol. 11 no 1: pp 92-104.\n[11]\tChen M, SK Ho, HF Zhou, PMK Pang, XL Hu, Ng DTW, Tong KY:Interactive rehabilitation robot for hand function training. In Proc. IEEE International Conference on Rehabilitation Robotics ICORR.Kyoto, Japan; 2009:777–780.\n[12]\tM. H. Rahman, M. J. Rahman, O. L. Cristobal, M. Saad, J. P. Kenné and P. S. Archambault \" Development of a whole arm wearable robotic exoskeleton for rehabilitation and to assist upper limb movements.\" Robotica CJO 2014, doi:10.1017/S0263574714000034."]}

To assist the elderly and/or physically disabled people who no longer possess proper function of their hand motion, we have been developing a robotic assistive device to rehabilitate the hand motions to improve quality of life. The proposed assistive device will be comprised of three degrees of freedom enabling basic movements and hand function. In this research we have focused on the modeling and control of the proposed assistive device. To achieve the dynamic simulation of the developed model, nonlinear computed torque control technique was employed. In the simulation, the trajectory tracking performance of the controller was evaluated.

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.

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.

Transition from latency to active tuberculosis requires Mycobacterium tuberculosis (Mtb) to penetrate the phagosomal membrane and translocate to the cytosol of the host macrophage. Quantitative two-photon fluorescence resonance energy transfer (FRET) microscopy is developed to measure cytosolic translocation using Mycobacterium marinum (Mm) as a model organism for Mtb. Macrophages were infected with Mm or non-pathogenic Mycobacterium smegmatis (Ms) as a control, then loaded with a FRET substrate. Once translocation occurs, mycobacterium-bearing β-lactamase cleaves the substrate, resulting in decrease of FRET signal. Quantification of this FRET signal change revealed that Mm, but not Ms, is capable of translocating to the cytosol.

There has been wide range of expansion in hand gestures close in style, pattern, movement and feature as well as in meaning. From that aspect this following paper confabs an improved version of hand gesture recognition based on segmentation process and backpropagation algorithm through the analysis of myoelectric signals generates from the movement of brachioradialis muscle and antebrachial vein of lower portion of forearm as well as flexor carpi radialis tendon and flexor digitorum superficial tendons of upper portion of wrist connected to forearm. From the received forearm electromyography (EMG) signals separation of individual signals through segmentation and corresponding evaluated values are used as the input of feed forward artificial neural network which would act as a classifier to obtain required distinguishable signals or commands to communicate. The neural network is trained with number of signals of different people and tested with other signals for minimum errors as well. Without considering depth or distance this proposed method will provide a good variety of classified signals for small changes in muscular signal changes for patient monitoring through virtual command.

Bangla handwritten character recognition is one of the complex works because of the wide variation of the Bangla character. In this paper we proposed a new approach for extracting the features of Bangla handwritten characters and then recognition of those characters using artificial neural network has done. For the feature extraction process we have used a row and column basis segmentation process in which a binary image the ratio of the dispersion of black from the top of the segment and total number of column or row pixels is measured on that particular segment as well as for each segment and then from this data a feature matrix of M×1 dimension is created for each character. When features from all the characters are extracted then some of the data is used to train the feed forward neural network and after that some characters are used for testing. In our proposed method 94.3% recognition accuracy is obtained when tested on some handwritten Bangla characters.

Motion detection is now very much popular for its different type of applications. And the most important thing for motion detection is the background updating procedure. For background updating, all the existing work is done actually depend on the present and past frame. In this paper we proposed a new background updating model for motion detection which mainly differs by considering the future frame. This work is done by taking a number of frames initially to find median from these frames and stored as the past background. Then some frames are taken as future frames and computes a future background from these frames by finding the median. Now if motion occurs in any frame which lies between the past background and this updated future background can be detected easily and accurately by comparing the frames with both of these two updated background. And after some moment the updated future background will be the past background and again some of the frames will be considered as the future frames to calculate the new future background. Our proposed method can update the background accurately as well as can detect motion or moving object perfectly. We have applied this method on various real time data and got promising results.