Influence of moisture concentration and hydrophobic material on induced stress in FCBGA package under reflow

Purpose This paper focuses on the fluid-structure interaction (FSI) analysis of moisture induced stress for the flip chip ball grid array (FCBGA) package with hydrophobic and hydrophilic materials during the reflow soldering process. The purpose of this paper is to analyze the influence of moisture concentration and FCBGA with hydrophobic material on induced pressure and stress in the package at varies times. Design/methodology/approach The present study analyzed the warpage deformation during the reflow process via visual inspection machine (complied to Joint Electron Device Engineering Council standard) and FSI simulation by using ANSYS/FLUENT package. The direct concentration approach is used to model moisture diffusion and ANSYS is used to predict the Von-Misses stress. Models of Test Vehicle 1 (similar to Xie et al., 2009b) and Test Vehicle 2 (FCBGA package) with the combination of hydrophobic and hydrophilic materials are performed. The simulation for different moisture concentrations with reflows process time has been conducted. Findings The results from the mechanical reliability study indicate that the FSI analysis is found to be in good agreement with the published study and acceptable agreement with the experimental result. The maximum Von-Misses stress induced by the moisture significantly increased on FCBGA with hydrophobic material compared to FCBGA with a hydrophilic material. The presence of hydrophobic material that hinders the moisture desorption process. The analysis also illustrated the moisture could very possibly reside in electronic packaging and developed beyond saturated vapor into superheated vapor or compressed liquid, which exposed electronic packaging to higher stresses. Practical implications The findings provide valuable guidelines and references to engineers and packaging designers during the reflow soldering process in the microelectronics industry. Originality/value Studies on the influence of moisture concentration and hydrophobic material are still limited and studies on FCBGA package warpage under reflow process involving the effect of hydrophobic and hydrophilic materials are rarely reported. Thus, this study is important to effectively bridge the research gap and yield appropriate guidelines in the microelectronics industry.

Immobilization of Potassium-Based Heterogeneous Catalyst over Alumina Beads and Powder Support in the Transesterification of Waste Cooking Oil

In this work, the beads and powder potassium hydroxide (KOH) and potassium carbonate (K2CO3) supported on alumina oxide (Al2O3) were successfully prepared via incipient wetness impregnation technique. Herein, the perforated hydrophilic materials (PHM) made from low-density polyethylene (LDPE) was used as the catalyst reactor bed. The prepared catalysts were investigated using TGA, XRD, BET, SEM-EDX, TPD, FTIR while spent catalysts were analyzed using XRF and ICP-AES to study its deactivation mechanism. The catalytic performance of beads and powder KOH/Al2O3 and K2CO3/Al2O3 catalysts were evaluated via transesterification of waste cooking oil (WCO) to biodiesel. It was found that the optimum conditions for transesterification reaction were 1:12 of oil-to-methanol molar ratio and 5 wt.% of catalyst at 65 °C. As a result, the mesoporous size of beads KOH/Al2O3 and K2CO3/Al2O3 catalysts yielded 86.8% and 77.3% at 2 h’ reaction time of fatty acids methyl ester (FAME), respectively. It was revealed that the utilization of PHM for beads K2CO3/Al2O3 increase the reusability of the catalyst up to 7 cycles. Furthermore, the FAME produced was confirmed by the gas chromatography-mass spectroscopic technique. From this finding, beads KOH/Al2O3 and K2CO3/Al2O3 catalysts showed a promising performance to convert WCO to FAME or known as biodiesel.

The Effect of Different Ratios of Malonic Acid to Plyvinylalcohol on Electrochemical and Mechanical Properties of Polyacrylonitrile Electrospun Separators in Lithium-Ion Batteries

The present study aimed to investigate the mechanical, thermal, and electrochemical properties of Polyacrylonitrile (PAN) electrospun separators in the presence of Polyvinylalcohol (PVA) hydrophilic materials and Malonic Acid (MA) crosslinker inside the lithium-ion batteries. The results showed that the M3 modified separator with the MA to PVA+MA (wt./wt.) optimum ratio of 37.5 % had the best performance in all tests. This separator had a value of 3.16 mS/cm in the ion conductivity test. Additionally, it had an electrolyte uptake of 1172 % (2.39 times more than the neat PAN separator) and thermal shrinkage of 7.4 % at 180 °C, where this value was 14.5 % for neat PAN separator at the same experimental condition. Furthermore, the acceptable performance in the battery performance tests was compared with other separators.

Strengthening of Porcine Plasma Protein Superabsorbent Materials through a Solubilization-Freeze-Drying Process

The replacement of common acrylic derivatives by biodegradable materials in the formulation of superabsorbent materials would lessen the associated environmental impact. Moreover, the use of by-products or biowastes from the food industry that are usually discarded would promote a desired circular economy. The present study deals with the development of superabsorbent materials based on a by-product from the meat industry, namely plasma protein, focusing on the effects of a freeze-drying stage before blending with glycerol and eventual injection molding. More specifically, this freeze-drying stage is carried out either directly on the protein flour or after its solubilization in deionized water (10% w/w). Superabsorbent materials obtained after this solubilization-freeze-drying process display higher Young’s modulus and tensile strength values, without affecting their water uptake capacity. As greater water uptake is commonly related to poorer mechanical properties, the proposed solubilization-freeze-drying process is a useful strategy for producing strengthened hydrophilic materials.

Comparison of Botryococcus braunii and Neochloris vigensis Biofilm Formation on Vertical Oriented Surfaces

Biofilm technology is a cost-effective process for microalgae biomass production. Materials can be successfully used as microalgae biomass adhesion carriers. The productivity of two different microalgal strains, Neochloris vigensis, and Botryococcus braunii, were compared in an opened pond system on eleven different surfaces (cork, sponge towel, denim, plexiglass, stainless steel, silicone rubber, glass, geotextile, and three different patterned plexiglass). Biomass attachment on the various materials was monitored for 16 days of cultivation. Various parameters were tested during cultivation, such as pH, cell concentration, chl-a, NO3-, PO43-, lipids, total proteins, and carbohydrates. Contact angle and surface energy were used to determine the surface characteristics. Plexiglass resulted in the best performance in the case of B.braunii (28.3 g/m2), while in the case of N.vigensis, sponge towel exhibited the highest productivity (17.8 g/m2). Based on the results, the algal strain affects the attachment, and hydrophilic materials can be as efficient as hydrophobic ones.

DEVELOPMENT OF NASAL TAMPONS WITH PRESERVATION OF THE FUNCTIONS OF NASAL RESPIRATION TO STOP NASAL BLEEDING

The use of the tampons made of hydrophilic materials while maintaining the function of nasal breathing allows avoiding the complications in the postoperative period, however, their use is complicated by the lack of domestic and high cost of the foreign analogues. The aim of the work is to develop pneumatic nasal tampons made of hydrophilic materials while maintaining the function of nasal breathing. Materials and research methods. Endoscopic examination of the nasal cavity was performed ОП 100 volunteers (mean age 38.4±1.5 years, of which 58 were men (58%) and 42 women (42%)) with the determination of the parameters of the nasal cavity and nasopharynx. Based on the analysis of the data obtained, the sizes and design features of the nasal tampons are proposed. Substantiated material for the manufacture of nasal tampons. The absorption capacity of the nasal tampons was studied. Results. The selected material for the manufacture of nasal tampons - cellulose. Based on the determination of the parameters of the nasal cavity, the optimal sizes of nasal tampons are proposed: TH2 (14x64x7 mm); TH3 (19x84x7 mm). The design features of the tampons have been determined. ne indications have been developed for the ше of certain types of the tampons. It has been proven that the nasal tampons have a high absorption capacity (1721.0±14.8%), which will ensure high-quality and effective hemostasis. Conclusion. An import-substituting technology for the manufacture of the nasal tampons with preservation of the function of nasal breathing has been developed, what allows to ensure high-quality and effective hemostasis.

Optimization of Nodule and Height Sizes for Mixed Hydrophilic and Hydrophobic Surfaces

Patterned surfaces of hydrophobic and hydrophilic materials are considered to sustain dropwise condensation, providing the benefits of both materials and creating a surface with a low energy barrier for nucleation and capable of sustaining dropwise condensation. Surface heights, nodule sizes, and flow rates are evaluated on square-patterned surfaces to maximize mass collection. A thermal model is used to assess surface performance and includes an equivalent thermal resistance for diffusion. Flow rates of 15, 25, 50, and 100 m/s with nodule sizes between 0.1 mm to 3.6 mm are evaluated. Surface heights of 0.25, 0.5, 1, and 2 m are also assessed. For flow rates greater than 50 m/s, turbulent flow optimum nodule size is between 0.2 mm and 0.6 mm. Surfaces greater than 1 m in height at flow rates less than 50 m/s maximize mass with nodule sizes of 1.4 mm and 2 mm.

Antimicrobial Assay on PVDF Nanofiber Membrane

Many researches concentrated on development of antimicrobial membranes for many applications such as air or water filtration. Disk diffusion was well-known conventional method for antimicrobial assay. However, this method is preferable to hydrophilic materials, where inhibition zone was easily observed. For hydrophobic materials, negative test was always shown, except increase in antimicrobial loading. In this study, glucose fermentation was introduced as a new method for antimicrobial assay. The survived and viable bacteria either at the surface or attached inside the membranes could ferment glucose resulting in acid production and changing color of indicator in the glucose solution from pale orange to pink. FU8M and FA8M nanofiber membrane, loading with AgNO3 and Benzalkonium chloride (0.3-1.0%) were used as hydrophobic and hydrophilic membrane, respectively. The water absorption of these membranes took 2 h and 2 min, respectively, showing that the latter membrane improved its wettability. It is found that FU8M membrane showed no inhibition zone when the antimicrobial loading less than 1%, whereas the FA8M membrane showed inhibition zone from 8.6-14 mm, depending on antimicrobial loading. However, when glucose fermentation method was used, membranes showed the positive test after 9 hours of incubation at the antimicrobial concentration of 0.5%. Hence, this new method can be used as antimicrobial testing for membrane with simple and cost effective.