Dye-sensitized solar cells (DSSCs) have been widely studied due to several advantages, such as low cost-to-performance ratio, low cost of fabrication, functionality at wide angles and low intensities of incident light, mechanical robustness, and low weight. This paper summarizes the recent progress in DSSC technology for improving efficiency, focusing on the active layer in the photoanode, with a part of the DSSC consisting of dyes and a TiO2film layer. In particular, this review highlights a huge pool of studies that report improvements in the efficiency of DSSCs using TiO2nanotubes, which exhibit better electron transport. Finally, this paper suggests opportunities for future research.

Flexural behavior of printed circuit boards (PCB) is well known for the major failure mechanism under board level or product level mobile phone drop tests. This behavior induces high peeling stress between PCB and IC package. This stress causes failure including both solder joint crack and pad cratering, which leads to malfunction such as phone dead or power off. Therefore, for a more reliable mobile phone design, it is important to accurately predict behavior of the PCB. In the past, isotropic or orthogonal linear elastic model have been used for simulating PCB in finite element analysis. Also, since PCB consists of multiple layers with woven glass fiber epoxy resin composite (FR-4) and copper foils, a multilayered PCB model was developed in order to consider material properties that change along the different plies. In this paper, the isotropic elastoplastic model was employed in order to efficiently predict behavior of PCB. Tensile and flexural test of PCB were conducted initially to evaluate mechanical characteristics and obtain representative material properties. Then, simulation of flexural test was performed to develop the finite element modeling. Finally, a drop test of mobile phone adopted with PCB bare board, which did not include IC packages, was examined. Also, the strain gage was used for measuring strain of PCB. This result was compared with drop simulation results of mobile phone, which used finite element modeling suggested. In conclusion, from an industry standpoint, finite element modeling of PCB using isotropic elasoplastic model was useful and efficient.

Left ventricular assist device (LVAD) has been highlighted as a new treatment option in the end-stage heart failure (HF). Kidney outcome after LVAD in severe cardiorenal syndrome (CRS) patients requiring kidney replacement therapy (KRT) is unclear. We investigated the impact of preoperative KRT on kidney function and survival in LVAD patients with severe CRS. A total of 50 patients followed up for at least 1 year after LVAD implantation was analyzed. The primary outcomes were estimated glomerular filtration rate and survival rate. Patients were divided into two groups depending on in-hospital KRT before LVAD implantation: the control group ( n = 33) and the KRT group ( n = 17). Postoperative KRT was performed for 76.5% of patients in the KRT group, and all of them discontinued KRT before discharge. There were no statistically significant differences in the degree of eGFR decline in survivors according to preoperative KRT. Although there were no statistically significant differences in the degree of eGFR decline in survivors regardless of preoperative KRT, old age (β −0.94, p < 0.01), preexisting chronic kidney disease (β −21.89, p < 0.01), and high serum creatinine (β −13.95, p < 0.01) were identified as independent predictors of post-LVAD eGFR decline. Mortality rate was higher, and more patients progressed to end-stage kidney disease in KRT group than control group. However, LVAD still can be considered as the treatment option in end-stage HF patients with severe CRS requiring KRT, especially in those with young age and previous normal kidney function.

Recently, product manufacturers of mobile phone have to meet to high demands that allow their products endure variable bad environments exposed throughout the customers’ use. Especially, mobile phones need to resist to high humidity and general waterproofing that is prevalent in everyday usage. However, most previous studies related to seal material or methods for sealing assembly have been focused on heavy industry or automotive industry. In this paper, the aim is to predict waterproof possibility of mobile phone by using finite element analysis in design step. The criteria of waterproof condition for mobile phones was based on IEC60529 IPX-7 level[1]. This paper studied behavior characteristics and properties of the specialized rubber material for sealing the mobile phone housing. Constitutive equation for specialized seal rubber material was applied to the 3rd order Ogden function. Then, the correlation with test and finite element model was studied. Using the correlated finite element model for specialized seal rubber, evaluated behavior characteristics for seal rubber 2D shape and studied waterproof possibility analysis 3D model of mobile phone. The proposed suggestion is expected to predict waterproof possibility for mobile phone efficiently. Evaluation method of 2D finite element model will be useful for decision design specification of seal rubber shape at preceding design step. And evaluation method of 3D finite element model will predict waterproof possibility before tooling the mold and will save the costs at development step in industry.