Radon (222Rn), an inert gas, is considered a silent killer due to its carcinogenic characteristics. Dhaka city is situated on the banks of the Buriganga River, which is regarded as the lifeline of ...Dhaka city because it serves as a significant source of the city's water supply for domestic and industrial purposes. Thirty water samples (10 tap water from Dhaka city and 20 surface samples from the Buriganga River) were collected and analyzed using a RAD H2O accessory for 222Rn concentration. The average 222Rn concentration in tap and river water was 1.54 ± 0.38 Bq/L and 0.68 ± 0.29 Bq/L, respectively. All the values were found below the maximum contamination limit (MCL) of 11.1 Bq/L set by the USEPA, the WHO-recommended safe limit of 100 Bq/L, and the UNSCEAR suggested range of 4-40 Bq/L. The mean values of the total annual effective doses due to inhalation and ingestion were calculated to be 9.77 μSv/y and 4.29 μSv/y for tap water and river water, respectively. Although all these values were well below the permissible limit of 100 μSv/y proposed by WHO, they cannot be neglected because of the hazardous nature of 222Rn, especially considering their entry to the human body via inhalation and ingestion pathways. The obtained data may serve as a reference for future 222Rn-related works.
Traditional treatment approaches for cancer involve intravenous chemotherapy or other forms of drug delivery. These therapeutic measures suffer from several limitations such as nonspecific targeting, ...poor biodistribution, and buildup of drug resistances. However, significant technological advancements have been made in terms of superior modes of drug delivery over the last few decades. Technical capability in analyzing the molecular mechanisms of tumor biology, nanotechnology─particularly the development of biocompatible nanoparticles, surface modification techniques, microelectronics, and material sciences─has increased. As a result, a significant number of nanostructured carriers that can deliver drugs to specific cancerous sites with high efficiency have been developed. This particular maneuver that enables the introduction of a therapeutic nanostructured substance in the body by controlling the rate, time, and place is defined as the nanostructured drug delivery system (NDDS). Because of their versatility and ability to incorporate features such as specific targeting, water solubility, stability, biocompatibility, degradability, and ability to reverse drug resistance, they have attracted the interest of the scientific community, in general, and nanotechnologists as well as biomedical scientists. To keep pace with the rapid advancement of nanotechnology, specific technical aspects of the recent NDDSs and their prospects need to be reported coherently. To address these ongoing issues, this review article provides an overview of different NDDSs such as lipids, polymers, and inorganic nanoparticles. In addition, this review also reports the challenges of current NDDSs and points out the prospective research directions of these nanocarriers. From our focused review, we conclude that still now the most advanced and potent field of application for NDDSs is lipid-based, while other significantly potential fields include polymer-based and inorganic NDDSs. However, despite the promises, challenges remain in practical implementations of such NDDSs in terms of dosage and stability, and caution should be exercised regarding biocompatibility of materials. Considering these aspects objectively, this review on NDDSs will be particularly of interest for small-to-large scale industrial researchers and academicians with expertise in drug delivery, cancer research, and nanotechnology.
•Thermo physical properties of PCM could be enhanced by dispersing nanoparticles.•Surface/physical properties of nanoparticle could affect the thermal properties of PCM.•CNT and CNF showed better ...performance to enhance the thermal properties of PCM.•Some predictions in NePCM literature needs further investigations.
A review of current experimental studies on variations in thermophysical properties of phase change material (PCM) due to dispersion of nanoparticles is presented in this article. Dispersed carbon nanotubes/fiber and different metal/metal oxide nano particles in paraffin and fatty acids might be a solution to improve latent heat thermal storage performance. Thermophysical properties such as thermal conductivity, latent heat, viscosity and super cooling of phase change materials (PCM) could be changed for different physical properties of dispersed nanoparticle such as size, shape, concentration and surface properties. Among the nano particles, comparatively carbon nanotubes and carbon nano fiber have shown better performance in enhancing the thermal properties of PCM for their unique properties. The present review will focus on the studies that describe how the surface, chemical and physical properties of nanoparticle could affect the thermal properties of PCM with the help of available explanations in the literature.
The application of thermal energy storage (TES) system with phase change material (PCM) is an effective way for energy conservation and greenhouse gas (GHG) emission reduction. Global warming is ...increasing along with the energy consumption. Many researchers are concerned about this present global environmental problem for fossil-fuel burning. Thermal energy storage system with phase change material is observed as a potential candidate for mitigating this problem. This paper emphasizes the opportunities for energy savings and greenhouse-gas emissions reduction with the implementation of PCM in TES systems. For instance, about 3.43% of CO2 emission by 2020 could be reduced through the application of PCM in building and solar thermal power systems. Similarly, energy conservation and GHGs emission reduction by other PCM applications for thermal comfort of vehicles, transport refrigeration, engine cold start, greenhouse and waste heat management are also presented. In addition, some present investigations on the performance improvement of the phase change materials are addressed.
Drones are a form of remote-controlled aircraft that can take to the air without the need for a human pilot. An increasing number of people are looking into using drones for a variety of tasks, ...including but not limited to operations in hazardous areas, environmental monitoring and sensing, aerial spreading of fertilizer and agricultural chemicals, disaster management and transporting goods from one location to another. Drones are receiving a lot of attention for these and other uses. A drone's position and navigation can only be controlled by the remote pilot via radio frequency (RF) transmission between the drone and the remote pilot. In order to facilitate two-way communications between the drone and its operator, it is necessary to keep a tight eye on the telemetry data and supplementary sensor data being sent and received by the drone in real time. Unmanned flying would not be conceivable without a flexible and dependable communication system. Due to the necessity of complete spatial coverage for drone communication, the antenna radiating in an isotropic pattern presents itself as a promising option for unmanned flying. Therefore, microstrip patch antenna is an excellent choice for drone applications.
Exergy analysis has become an important tool for thermodynamic assessment of power generation systems. In the present study, thermodynamic performance (energy and exergy) analysis is performed for a ...solar thermal power plant located in Shiraz, Iran. In addition, a computational exergy analysis is performed to show the possible improvement of this power plant integrating with Phase Change Material (PCM) storage. Consequently, it is found that overall energy efficiency without PCM storage is about 30% while the exergy efficiency is about 10%. However, about 30% overall exergy efficiency can be achieved for the case of using PCM storage along with the solar collector.
More than 170 countries have already established renewable energy targets to meet their national increasing energy demand and also to keep their environment sustainable. Due to a number of features, ...the use of the multi-megawatt solar photovoltaic (PV) power plants is becoming the preferred choice for escalating and updating the power systems all over the world. Moreover, the solar PV power plant is also the first choice for meeting rapidly growing demands; as it can be installed relatively quickly, say in 6-12 months, compared to that of the fossil-fuel-based plants that may require more than 4-5 years. The traditional low-voltage (288-690 V) converter-based system requires a step-up transformer and a line filter to interconnect a solar PV power plant with medium-voltage grids. Recently, the use of medium-voltage converters without a step-up transformer and a line filter has become more attractive for direct medium-voltage grid integration of solar PV power plants. This paper aims to review the necessity and the technical challenges in developing medium-voltage power electronic converters, including the converter circuit topologies and control techniques used in the development of medium-voltage converters to interconnect solar PV power plants to medium-voltage grids directly. In this paper, a comprehensive review of the current research activities and the possible future directions of research to develop medium-voltage converter technologies to provide for a cost-effective grid integration of solar PV power plants are presented.
Coastal Mangroves are facing growing threats due to the harmful consequences of human activities. This first-ever detailed study of natural radioactivity in soil samples collected from seven tourist ...destinations within the Sundarbans, the world's largest mangrove forest, was conducted using HPGe gamma-ray spectrometry. Although the activity levels of 226Ra (11 ± 1–44 ± 4 Bq/kg) and 232Th (13 ± 1–68 ± 6 Bq/kg) generally align with global averages, the concentration of 40K (250 ± 20–630 ± 55 Bq/kg) was observed to surpass the worldwide average primarily due to factors like salinity intrusion, fertilizer application, agricultural runoff, which suggests the potential existence of potassium-rich mineral resources near the study sites. The assessment of the hazard parameters indicates that the majority of these parameters are within the recommended limits. The soil samples do not pose a significant radiological risk to the nearby population. The results of this study can establish important radiological baseline data before the Rooppur Nuclear Power Plant begins operating in Bangladesh.
•First-ever detailed study of natural radioactivity in soil samples within the Sundarbans, the world's largest mangrove forest.•Elevated activity concentrations of 40K were discovered, indicating the potential presence of potassium-rich mineral resources in the vicinity of the study sites.•Present results serve as baseline for the upcoming commissioning of the Rooppur Nuclear Power Plant in Bangladesh.
Wearable antennas have grown in popularity in recent years as a result of their appealing features and prospects to actualize lightweight, compact, low-cost and adaptable wireless communications and ...surroundings. These antennas have to be conformal and made of lightweight materials in a low-profile arrangement when attached to various parts of the human body. Near-body operation of these antennas should be possible without degradation. When these characteristics are taken into account, the layout of wearable antennas become challenging, especially when textile substrates are investigated, high conductivity materials are used during manufacturing procedures and body binding scenarios have an impact on the design's performance. Several of these issues arise in the context of body-worn deployment, despite modest changes in magnitude between implementations. This paper examines the multiple issues and obstacles encountered in the construction of wearable antennas as well as the range of materials used, and the Specific Absorption Rate (SAR) effects employed as well as the bending scheme. An overview of the innovative features and their separate approaches to addressing the difficulties lately raised by work in this field conducted by the scientific community is provided as an appendix.
PDF
