Search Results (4)

Currently, there is a shortage of potable water in several regions. Various alternative methods exist for producing purified water; however, one particular technology known as solar desalination is gaining prominence as a sustainable and environmentally friendly solution. Solar desalination harnesses solar energy to produce fresh water in regions with abundant sunlight. This study involved the fabrication of a nanostructured porous material composed of copper using anodization, followed by copper electroplating. In order to create three distinct nanoporous structures, we utilized three anodization periods of 40 min, 60 min, and 80 min. Subsequently, these structures underwent a copper deposition process for 30 min using the copper electroplating technique. Scanning electron microscopy (SEM), energy-dispersive X-ray (EDAX), and X-ray diffraction (XRD) techniques were utilized to analyze the characteristics of the copper-plated nanoporous structure. Three distinct samples were utilized in solar desalination experiments, employing solar stills over a span of three consecutive days, with each sample being tested on a separate day. All three samples underwent desalination, unlike the standard solar still, which did not include any sample. Our observation revealed that the sample, which underwent 60 min of anodization followed by copper electroplating, had a significantly greater evaporation rate of 22.22% compared to the conventional still. Full article

In order to solve the frosting and blockage problem of an air conditioning evaporator’s fin in winter, the nanoporous aluminum plates with low surface energy has been proposed in this paper, which are fabricated by an anodizing method and then modified by lauric acid. The nanoporous aluminum plates with different nanoporous diameters ranging from 15 nm to 400 nm are obtained by changing the magnitude of the oxidation current. The surface contact angle of the nanoporous aluminum plates is an important factor influencing its surface frost and condensation. The test results show that the surface contact angle is decreased with the increasing of nanoporous diameter. When the nanoporous aluminum plates are modified by lauric acid, the contact angle is proportional to the nanoporous diameter, and the maximum contact angle can reach about 171°. A set of experimental instruments has been set up to simulate the typical winter climate in northern China, and the frosting properties of the nanoporous aluminum plate’s fin is analyzed by experiment. The results show that increasing the contact angle of aluminum plates can effectively improve its anti-frosting properties. The average frosting rate of the aluminum plate with the contact angle of 60° is about 0.33 [g/(min∙m²)], which is 1.74 times that of the aluminum plate with the contact angle of 171°, whose frosting rate is about 0.19 [g/(min∙m²)]. After taking the expanded aperture processing to the aluminum plate, the diameter with 30 nm, 100 nm, 200 nm, 300 nm, and 400 nm nanoporous aluminum plates are obtained and the polished aluminum plates are also prepared for comparing. Through the test results, the nanoporous aluminum plates are shown to have anti-frosting properties, and the nanoporous aluminum plates with diameter of 300 nm are shown to have the best anti-frosting properties. The calculation mode of frosting growth is derived on the base of experimental results. This research will be helpful in indicating the potential research area of the low-carbon-emission and energy-saving technology for the researchers all over the world. Full article

Measurement of moisture at ppm or ppb level is very difficult and the fabrication of such sensors at low cost is always challenging. High sensitivity is an important parameter for trace level (ppm) humidity sensors. Anelectronic detection circuit for interfacing the humidity sensor with high sensitivity requires a simple hardware circuit with few active devices. The recent trends for increasing the sensitivity include fabricating nanoporous film with a very large surface area. In the present work, the sensitivity of a parallel plate capacitive type sensor with metal oxide sensing film has been significantly improved with an aim to detect moisture from 3 to 100 ppm in the industrial process gases used to fabricate semiconductors and other sensitive electronic devices. The sensitivity has been increased by (i) fabricating a nanoporous film of aluminum oxide using the sol-gel method and (ii) increasing the cross-sectional area of a parallel plate capacitor. A novel double sided capacitive structure has been proposed where two capacitors have been fabricated—one on the top and one on the bottom side of a flat alumina substrate—and then the capacitors are connected in parallel. The structure has twice the sensitivity of a single sensor in the same ppm range but the size of the structure remains unchanged. The important characteristics of the sensors such as the sensitivity (S = $\frac{\Delta C}{\Delta ppm}\times 100$ ), the response time (t_r), and the recovery time (t_c) are determined and compared with a commercial SHAW, UKdew point meter. The fabricated double sided sensor has comparable sensitivity (S = 100%, t_r (s) = 28, t_c (s) = 40) with the commercial meter (S = 100.5%, t_r (s) = 258) but has a faster response time. The proposed method of sensitivity enhancement is simple, and mass producible. Full article

Anodic porous alumina is a known material based on an old industry, yet with emerging applications in nanoscience and nanotechnology. This is promising, but the nanostructured alumina should be fabricated from inexpensive raw material. We fabricated porous alumina from commercial aluminum food plate in 0.4 M aqueous phosphoric acid, aiming to design an effective manufacturing protocol for the material used as nanoporous filler in dental restorative composites, an application demonstrated previously by our group. We identified the critical input parameters of anodization voltage, bath temperature and anodization time, and the main output parameters of pore diameter, pore spacing and oxide thickness. Scanning electron microscopy and grain analysis allowed us to assess the nanostructured material, and the statistical design of experiments was used to optimize its fabrication. We analyzed a preliminary dataset, designed a second dataset aimed at clarifying the correlations between input and output parameters, and ran a confirmation dataset. Anodization conditions close to 125 V, 20°C, and 7 h were identified as the best for obtaining, in the shortest possible time, pore diameters and spacing of 100–150 nm and 150–275 nm respectively, and thickness of 6–8 µm, which are desirable for the selected application according to previously published results. Our analysis confirmed the linear dependence of pore size on anodization voltage and of thickness on anodization time. The importance of proper control on the experiment was highlighted, since batch effects emerge when the experimental conditions are not exactly reproduced. Full article