This paper proposes a novel robust blind color image watermarking technique that combines entropy analysis, lifting wavelet transform (LWT), QR factorization, and discrete cosine transform (DCT) for copyright protection. The RGB components of the color image are first separated, and the R component is then subjected to the 2-level LWT. Following DCT is applied to the 2-level LWT's high-frequency sub-band, the DCT coefficients are separated into 4x4 non-overlapping blocks. Each chosen block is then subjected to QR factorization, and the watermark is embedded in the first row and first column element of the upper triangular matrix. Numerous simulated tests show that the presented scheme is highly imperceptible and robust to attacks. The presented watermarking scheme performs better than the others in terms of invisibility, according to comparisons with comparable schemes.

Abstract: This paper presents simulation technique for life assessment of the insulation of the power transformer. Load and ambient temperatures are two important factors that influence the hot spot of transformers. The transformer hot spot temperature is one of the most critical parameter in determining the life of transformer paper insulation. The simulation (Matlab Software Package) is based on related international standards as the IEC 60076-7:2005 loading guide method. Load and ambient temperatures of the transformer obtain from General Electrical Company and meteorology office of Libya are used as the input for the simulation together with transformer parameters from heat run test. Hottest spot temperature and loss-of-life are calculated. Lifetime of transformer is predicted. Keywords: Hot-spot temperature, power transformer, top-oil temperature, loss of life

Abstract

As technological advancements continue to revolutionize teaching, the use of technology in both college/university and classrooms is making flipped

learning a trending instructional model. The roles and responsibilities of instructors and students often require a new or enhanced skill set where the instructor designs intentional learning experiences to engage students outside of the classroom. This research was conducted to investigate the effectiveness of flipped learning strategy to overcome the educational communication problems. Also, it has been explained the definition of the flipped classroom and its impact on course evaluations and student outcomes. Besides, it has been discussed the comparison between the flipped learning strategy and the traditional way of teaching. As well, it has been explained some advantages and disadvantages of the flipped classroom. Above and beyond, it has been mentioned the most important critiques against the flipped leaning. More to the point, it has been shown some steps to implement the flipped classroom strategy. As well as, it has been presented some reasons of why should be flipped our classrooms. Ultimately, some important recommendations have been given to guarantee an effective learning in the education process.

Key words:  flipped classrooms, flipped learning, higher education, technological advancement, effective flipping ,

Vortex airflow-assisted melt differential electrospinning for preparing superfine fiber yarns was proposed. This method with solvent-free exhibits a higher yield of 20 ± 5.17 m/min compared to the range of 0–5 m/min achieved by solution electrospinning with organic solvents. Simulation and high-speed photography show that the fibers are aggregated by suction airflow and twisted into yarns by vortex airflow. Polylactic acid (PLA) superfine fiber yarns exhibit fine fiber diameters ranging from 0.96 to 5.57 μm, a yarn diameter of 211.7 ± 40.8 μm, and a high tensile strength of 39.4 ± 3.12 MPa. Furthermore, these PLA melt electrospun yarns can be woven into fabric with a water contact angle of 120.1° and triboelectric voltage of 7.41 V, demonstrating their potential in self-cleaning textiles and flexible smart textiles. Moreover, this method is generally applicable to thermoplastic polymers including polyethylene …

A design of a geothermal heat pump heating, ventilating, and air conditioning system has been done for XYZ Indianapolis School by using renewable energy. Geothermal energy is one of the important energies that has proved itself in air conditioning systems all over the world. The design was classified in three points as follows. Using borehole heat exchanger (BHEs) vertical type, heat pump and all its equipment such as mechanical room, pipes, and fitting design to cover the total load of the school the results were 20 boreholes and a total flow rate of 60 gpm (3 gpm/bore) of 20 % propylene solution, and spacing 20 ft with 1.1 Hp and 6.5 in impeller size. For individual borehole design, the results were 15 boreholes and a total power consumption 1.1 kW. For the ventilation design, the peak load for heating is 42779 Btu/hr, and for cooling, it is 47779 Btu/hr. There are 4 boreholes, a 0.5 hp electric pump with a flow rate of 10 gpm a 40ft of H2O pressure drop, and a 10 hp fan integrated with a water-to-water heat pump. The total load we assumed for the heating supply in class 6 and the corridor are 10% and 25 %, respectively. The thermal resistance was calculated for each case according to the fluid flow rate. The ventilation load of the school is designed separately from the heating and cooling loads and connected to a water-water heat pump that will make the system work with high efficiency. Finally, we designed this project using Geothermal Energy, which is cleaner than conventional energy.

Solar energy, known for its abundance and sustainability, stands out as a preferred renewable energy source. Net-zero energy buildings (NZEBs) technology for an elementary school in Dayton, Ohio, was implemented using the f-chart, phi method, photovoltaic system, and the CombiSystem TRNSYS executable. The solar fraction achieved for the system was 56% utilizing the f-chart and phi method. The project required 181 collectors for heating and cooling loads and 578 photovoltaic collectors for electricity generation. Using the f-chart and phi method, the simple payback period was calculated to be 5 years. The optimal storage tank design was determined to be a 120-60 gallon configuration, achieving a solar fraction of 62.45%. The photovoltaic system generated energy valued at $191,135 annually, meeting the requirements for a net-zero energy building. This design provides clean energy without environmental pollution or CO₂ emissions. The total project cost amounted to $275,393.99, making it the most cost-effective design compared to alternative designs incorporating photovoltaic systems for cooling loads. 

Electrospun fibers membrane is considered an efficient drug carrier for transdermal drug delivery due to its breathability and high drug loading percentage, compared with coating film. However, pollution and safety risk caused by the use of organic solvents during the solution electrospinning process limit its industrialization and direct application in the biomedical field. Herein, a fiber membrane containing tandospirone was prepared using the melt electrospinning process and to be used for sustained drug release. The process of fiber preparation is an eco‐friendly and safe process due to the characteristics of solvent‐free. The in vitro drug release results showed that the fiber membranes containing tandospirone had slower initial drug release and higher end drug release compared with coating film containing tandospirone. The sustained‐release property can be attributed to the crystalline structure of fibers and …

The electrospun yarn for sutures has gained worldwide attention due to its fine fibers that resemble the extracellular matrix and its abundant functional sites. However, the use of a large number of toxic solvents poses safety risks and environmental pollution during production, making it challenging to directly apply electrospun yarn in the biomedical field. In this study, an environmentally friendly and safe method without toxic solvents was proposed for preparing antibacterial PLA ultrafine fiber sutures. This method involves melt electrospinning, hot‐stretching, low‐temperature plasma treatment, and chitosan grafting. The PLA ultrafine fiber sutures exhibit a high tensile strength which is 2.04 N before knotting and 1.57 N after knotting. The suture diameter is 118.7 μm and average fiber diameter is 1.72 μm. Chitosan grafted on the fiber surface provides excellent antibacterial properties for the sutures, with …

The new era of distance education opens up a new problem space for researchers to redefine educational needs. The COVID-19 lockdown with its tremendous consequences has affected the way of thinking and acting and has highlighted the merits of distance education. One of the most important of these problems is the inability of the lecturer technically to manage and present remote lectures, which resulted in the student's dissatisfaction with distance education. In this research, we have studied how to facilitate the work of the lecturer, who suffers from many problems, including the technical issues that need technical competencies in the field of information technology and modern technologies used in distance education, including the simulation system and displaying the system via the Internet, studying how to help the student also, in receiving distance education techniques and dealing with the programs used by the lecturer in skillfully presenting educational curricula. For that, the research focused on studying how to use a team to facilitate this work called the E-Learning Facilitator Team. This team plays a vital role in developing and maintaining an online program that is effective, and smooth, and that will support the realization of the planned learning outcomes. Faculty delivering courses online must be more than transmitters of knowledge; they must become facilitators of learning. Some highly seasoned instructors from the traditional on-ground environment will quickly adapt to the online model, while others may find the transition challenging at first [10].

An optimized image watermarking technique based on LU factorization and entropy analysis in combination with lifting wavelet transform and discrete cosine transform is presented in this paper. At first, the original image is decomposed by a 2-level lifting wavelet transform for obtaining the coefficients of a high-frequency subband followed by discrete cosine transform. Afterward, non-overlapping blocks are obtained by dividing the coefficients of discrete cosine transform whereas LU factorization is applied to each nonoverlapping blocks based on pseudo-random sequences. Then, the watermark is embedded into the first row, the first column element of the upper triangular matrix of LU factorization. The normalized cross-correlation (NC), and the peak signal-to-noise ratio (PSNR) are used to evaluate the invisibility and robustness of the presented technique. The experimental results have indicated that the presented technique fulfills all watermarking requirements in terms of invisibility, robustness, security, and capacity. The comparison with the existing scheme has shown that the proposed watermarking technique has a superior performance in terms of invisibility than the existing scheme.