Need For High Cost Research Articles

Silver nanowire/polyacrylamide/gelatin flexible stress, strain and temperature sensor

Wearable and flexible sensors with high sensitivity and repeatability are widely used in many fields. However, the problems of poor sensor stability and high cost need to be addressed. Here, we prepared flexible hydrogel sensors of gelatin, polyacrylamide (PAM) and silver nanowires (AgNWs) using ethylene glycol and water as binary solvents. The adhesion properties of PAM allow the sensor to adhere stably to the surfaces of (plastic, rubber, and metal) objects. This flexible sensor has a ability to respond accurately to signals generated by changes in temperature, stress, and strain. With a gauge factors (GF) of 1.0 at 150% strain and 1.8 at 658% GF, the sensor has a detection limit as low as 1%, demonstrating the sensor's ability to detect both large and small strains. Even when the sensor is cycled 1000 times at 1% strain, the signal peak remains within a stable range overall. In this paper, we develop a low-cost, non-toxic, wearable flexible sensor that can detect signals such as strain, pressure, human motion, temperature, and micro-expression changes.

Rapid detection and whole class control of quinolone antibiotics in pork based on surface‐enhanced Raman spectroscopy

AbstractThe problem of excessive quinolone antibiotic residues in pork has stimulated great attention from the international community. However, due to the diversity and structural similarity of quinolone antibiotics, it is difficult to perform multi‐residue rapid detection at the same time. Currently, antibiotic multi‐residue detection methods include ultra‐performance liquid chromatography (UPLC) and colloidal gold immunochromatography. However, it cannot be widely used in on‐site rapid detection due to its shortcomings such as the need for high cost and low sensitivity. Herein, we report the use of surface‐enhanced Raman spectroscopy (SERS) technology for the study of similar structures of quinolone antibiotics. A method for whole class control and rapid quantitative detection of all quinolone antibiotics in pork was established. By using the above method, the detection limit of single standard quinolone antibiotics was 10 μg L−1, and the detection limit of the mixed standard was 1 μg L−1, meeting the international requirements for the detection limit of quinolone antibiotics in pork. At last, by adding a variety of quinolone antibiotics to pork, the real detection set‐up was simulated. The recovery of standard addition was 86.6%–95.3%, and the whole class control method has been well applied, which is of great significance for the detection of pork quinolone antibiotics. Compared with colloidal gold immunochromatography, our method has 2.5 times the detection speed, 1/60 times the cost, and can be quantitatively detected. The method is simple, economical, and efficient and has great application value with broad application prospects in the field of rapid detection of pork antibiotics in the future.

A review on recent advancements in recovery of valuable and toxic metals from e-waste using bioleaching approach

This review is intent on the environmental pollution generated from printed circuit boards and the methods employed to retrieve valuable and hazardous metals present in the e-wastes. Printed circuit boards are the key components in the electronic devices and considered as huge e-pollutants in polluting our surroundings and the environment as a whole. Composing of toxic heavy metals, it causes serious health effects to the plants, animals and humans in the environment. A number of chemical, biological and physical approaches were carried out to recover the precious metals and to remove the hazardous metals from the environment. Chemical leaching is one of the conventional PCBs recycling methods which was carried out by using different organic solvents and chemicals. Need of high cost for execution, generation of secondary wastes in the conventional methods, forces to discover the advanced recycling methods such as hydrometallurgical, bio-metallurgical and bioleaching processes to retrieve the valuable metals generate through e-wastes. Among them, bioleaching process gain extra priority due to its higher efficiency of metal recovery from printed circuit boards. There are different classes of microorganisms have been utilized for precious metal recovery from the PCBs through bioleaching process such as chemolithoautotrophy, heterotrophy and different fungal species including Aspergillus sp. and Penicillium sp. The current status and scope for further studies in printed circuit boards recycling are discussed in this review.

Advances on the study of movable artificial vertebral body

At present, artificial vertebral implants have proven to be effective in the treatment of spinal tumors, infections, fractures and other diseases. However, the fusion artificial vertebral body can cause adjacent intervertebral joint degeneration and loss of original physiological curvature and activity. The movable artificial vertebral body can, to some extent, restore the normal physiological movement and reduce biomechanical changes of the spine, reducing the occurrence of complication. The design of movable artificial vertebral body is to equip movable device when the basis of reliable stability is obtained. According to its principle it can be divided into ball socket joint or elastic deformation. However the overall design of movable artificial vertebral body needs further improvement. Traditional mechanical processing methods are difficult to process complex prostheses and the agreement rate between traditional produced prostheses and lesions was low. While the emerging 3D printing technology can achieve individualized improvement of prosthesis, its slow rate and high cost need to be improved. The materials of movable artificial vertebral body includes metal, ceramics, biomaterials, high polymer materials and so on. Titanium alloy is the main material in metal materials, which is widely used, but its modulus of elasticity is still far from that of human bone and it lacks ideal bone fusion. Ceramic materials are rich in variety but fragile and poor in wear resistance. Biomaterials include autogenous bone, allogeneic bone, etc., with limited source and complicated operation. There are many kinds of polymer and biodegradable materials which obtain excellent and ideal properties. But their properties and applications need to be further studied. The movable artificial vertebral body still needs to be promoted and developed. The clinical experimental data is still insufficient, and long-term curative effect needs to be further observed and studied. This paper reviews the development, advantages, design, processing and materials of movable artificial vertebral bodies and provides useful reference for optimization design, processing and clinical application of movable artificial vertebral bodies.

Harnessing Cloud Computing Services for E-Learning Systems in Higher Education

The use of e-learning suggests the use of ICT to enhance the quality of learning and teaching. However, many higher education institutions, does not have e-learning platforms, resources and infrastructure necessary to implement this type of training. This is due to the need for high cost of basic infrastructure and applications challenges related projects it has to face. This article puts forward an overview on what is the current state of the use of cloud computing in e-learning in higher education context, where the use of computers is increasingly intensive. The article analyzes e-learning systems challenges and trends, the convenience of cloud computing for e-learning and the key benefits of e-learning on the cloud. The article exposes also some application solutions using cloud computing in e-learning for higher education, by presenting the most common architecture that has been adopted. Finally, this article discusses issues related to the implementation of cloud-based e-learning systems and presents some potential ways to overcome them.

Analytical model for ultimate loading capacities of continuous composite slabs with profiled steel sheets

Composite slabs with profiled steel sheet are widely applied in practical structures now. Plenty of literatures can be available about simply supported composite slabs with single span. However, continuous slabs always exist in high-rise building structures. In order to obtain the ultimate loading capacity of continuous composite slabs, the full scale test on slab specimens with high cost need to be carried out. This paper presented an analytical model for calculating the ultimate loading capacity of continuous composite slabs. Only the small-scale slide block test needed to be carried out for determining some mechanical parameters, resulting in less cost, compared with the conventional m-k test method. Various load conditions and parameters were considered in the analytical model. The comparison between test results and predicted results showed that the proposed method had enough precision. Furthermore, the simplified method was also proposed for practical design.

AFM기반 기계적 TNL 패터닝을 통한 PDMS 몰드제작

This study demonstrates the process of fabricating patterns using tribonanolithography (TNL),with laboratory-made micro polycrystalline diamond (PCD) tools that are attached to an atomic force microscope (AFM). The various patterns are easily fabricated using mechanical scratching, under various normal loads, using the PCD tool on single crystal silicon, which is the master mold for replication in this study. Then, polydimethylsiloxane (PDMS) replica molds are fabricated using precise pattern transfer processes. The transferred patterns show high dimensional accuracy as compared with those of TNL-processed silicon micro molds. TNL can reduce the need for high cost and complicated apparatuses required for conventional lithography methods. TNL shows great potential in that it allows for the rapid fabrication of duplicated patterns through simple mechanical micromachining on brittle sample surfaces.

A Review of Multilevel Inverter Based Active Power Filter

Use of nonlinear loads at high voltages has increased tremendously in industry. These non-linear loads distort power quality by generating harmonics. Conventional active filters have limitations in high power high voltage systems. Use of multilevel inverter in active filters effectively reduces harmonics in high voltage systems eliminating need of high cost and bulky transformer. This paper presents the state of art of different topologies of multilevel inverter (MLI) used for active power filters (APF), the different control techniques and advanced modulation methods. It is aimed to provide a broad perspective on the status of MLI based APF technology to researchers and application engineers dealing with power quality issues in high voltage systems.