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In this study, polypropylene meltblown nonwoven fabrics with different structure parameters such as fiber diameter, pore size, and areal density were prepared by the industrial production line. The morphology of meltblown nonwoven fibers was evaluated by using scanning electron microscope, and the diameter of fibers was analyzed by using image-pro plus software from at least 200 measurements. The pore size of nonwoven fabric was characterized by a CFP-1500AE type pore size analyzer. The filtration efficiency and pressure drop were evaluated by TSI8130 automatic filter. The results showed that the pressure drop of nonwoven fabrics decreased with the increase in pore size; the filtration efficiency and the pressure drop had a positive correlation with the areal density. However, when the areal density is in the range of 27–29 g/m2, both filtration efficiency and pressure drop decreased with the increase of areal density; when the areal density was kept constant, the filtration efficiency decreased as the pore size decreased; when the pore size of the meltblown nonwoven fabric is less than 17 μm, the filtration efficiency increased as the pore diameter decreased; when the pore diameter of the nonwoven fabric is larger than 17 μm. In a wide range, the pressure drop decreased as the fiber diameter decreased.

It is quite hazardous to produce the final product of oil or gas in a petrochemical refinery plant due to its flammable or combustible and explosive materials. Small mistakes can cause massive damage to life, property, pollution, injury, ecosystem, and business by fire. The entire system is challenging to manage. Therefore, fire risk assessment and forecasting are necessary to overcome personal, environmental, and refinery plants’ hazard situations. There have been four main threats in any refinery facility: electrical, mechanical, civil, and chemical issues, maximum cases its result burning. This research aimed to study and assess fire risk in the refinery plant by using a multi-stage early warning system and reducing the fire. The fire hazard safety layer technique would be used for our petrochemical process. Some equipment is set in place to forecast the danger and execution before and after it happens. Geographic information systems (GIS), remote sensing (RS) are some techniques for fire incidents tracking. Flame detectors, heat detectors, and gas detectors are used to maintain good contact in the entire risk analyzer portion. Various techniques and monitoring have been proposed to operate the plant efficiently and safely, like controlling, predicting, and pre-warning strategic planning.

Polyvinylidene fluoride (PVDF) fibrous membranes with fiber diameter from nanoscale to microscale were prepared by electrospinning. The structural parameters of PVDF fibrous membrane in terms of fiber diameter, pore size and its distribution, porosity or packing density, thickness, and areal weight were tested. The relationship between solution concentration and structural parameters of fibrous membrane was analyzed. The filtration performance of PVDF fibrous membrane in terms of air permeability and filtration efficiency was evaluated. The results demonstrated that the higher solution concentration led to a larger fiber diameter and higher areal weight of fibrous membrane. However, no regular change was found in thickness, porosity, or pore size of fibrous membrane under different solution concentrations. The air permeability and filtration efficiency of fibrous membrane had positive correlations with pore size. The experimental results of filtration efficiency were compared with the predicted values from current theoretical models based on single fiber filtration efficiency. However, the predicted values did not have a good agreement with experimental results since the fiber diameter was in nanoscale and the ratio of particle size to fiber diameter was much larger than the value that the theoretical model requires.

Densely populated countries like Bangladesh are facing challenges in the health care system with overcrowding, cost containment, and inadequate arrangement of the health care center in terms of increasing demand from patients. Running health care systems all over the country both private and public are unable to satisfy patients because of miss management, waste of time, and the lack of service. To identify and reduce the problem in the health care system, lean management plays an important role all over the world. Value stream mapping (VSM) is one of the proven widely used Lean techniques, to identify the flow of work, information, and structure for reducing waste of time and service stress which helps to make a good relationship between administration and service holder. VSM is a very primary stage in the Bangladesh health care system. This research aims to improve the health care system in Bangladesh and the study focuses on applying VSM at the cardiology department in Khulna Medical College Hospital, Khulna, Bangladesh. A patient survey is done for comparison of numerical results to real-life data in the cardiology department of Khulna Medical College hospital. In this study it could be shown that after implementing the VSM technique, the patient capacity increased by 39%, Ideal time improve 9.62% as well as utilizing time increase by 38.46%. This result inspires large scale implementation of the lean tool in the health care sector of a country like Bangladesh.

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Humidity has a substantial impact on biological and environmental factors. Improper relative humidity (too high or very low) can create discomfort for individuals and affect several systems and apparatus. On the other hand, the correct type of humidifying machinery and functions may facilitate reliable, economic, and trouble-free control of moisture. Humidity in the winter region is always too low, which causes anxiety. This study aims to develop a microcontroller-based system to identify and eliminate such low humidity problems. A control system is implemented to generate air humidity according to the need to decide whether the unit is working. A wireless sensor was used to measure the room’s relative humidity and temperature. The Humidifier is activated whenever the relative humidity is less than that of the setting’s value according to the standard humidity value. A humidifier is developed using vaporizing ultrasound, which can still be considered the automatic ultrasonic Humidifier (AUH). The setting is suitable in the winter zone or where the relative humidity is below the standard comfort value. In this study, data were recorded in Khulna, Bangladesh, between April and May of 2018. Most of the sensor’s recorded values were greater than the standard comfort Relative humidity, so the Humidifier was disabled. Humidifier activated while the sensor recorded lower relative humidity value with comparison to the standard set value.

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