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This work is to demonstrate a low cost and time-conserving technique to create nano-trenches by transferring nano-scale polymeric sidewalls into substrate. The polymeric sidewall is a vertically spreading layer deposited by spin-coating a polymer solution on a vertical template. By varying processing parameters such as the solution concentration or the spin-coating speed, the dimension of the sidewall can be changed, which, after pattern transfer, also changes the nano-trench dimension. In this work, high-resolution trenches of about 15 nm have been achieved after transferring straight line sidewalls into substrate. Other than straight line sidewall patterns, this method also fabricates ring-shaped patterns including circles, squares, and concentric squares. With various shapes of sidewall patterns, this technique has a potential to implement other practical applications such as fabricating high-resolution nanoimprint molds of 15 nm.

TiN metal hardmask has been used to improve etch selectivity to low-k materials and thereby gain better profile control. For 14 nm and smaller technology nodes, it is required that the TiN hardmask is completely removed in order to improve the aspect ratio for subsequent reliable metal deposition. Thus, a chemical cleaning formulation with high TiN etch selectivity toward Cu and low-k is required.

A wet cleaning formulation with tunable AlN etch rate approach was developed. The formula is compatible with Cu, Co and low-k materials, is able to remove etch residues and does not contain fluoride.

This work aimed to evaluate the influence of different acceleration systems on the properties of elastomeric compositions employed on the tire sidewall by means of the use of a lignin extracted from Eucalyptus as a substitute for oligomerized 2,2,4-trimethyl-quinoline (TMQ), a chemical additive of the rubber industry. For this purpose, six formulations were prepared varying the stabilizer type, TMQ or lignin for each acceleration system. The characterization was performed through rheological and mechanical properties, before and after accelerated aging in an oven and ozone chamber. In general, compositions with TMQ or lignin did not show significant differences in the results; however, different behaviors were observed in the three acceleration systems studied. The crosslink density decreased as the conventional acceleration system changed to semi-efficient and efficient. After accelerated aging, the specimens prepared with the semi-efficient and efficient systems showed the best retention results of the tear and tensile strength properties. In the ozone environment, samples prepared with the conventional and efficient system showed cracks on the surface. Therefore, it can be concluded that the semi-efficient system presented the best performance and that lignin can be used as a stabilizing additive, as it does not prejudice the natural rubber elastomeric compounds properties.

The increasing integration of chips necessitates improved heat dissipation solutions, which has promoted the development and combination of nanofluids and microchannels. However, balancing heat transfer enhancement and flow resistance remains challenging. Hence, firstly, five different sidewall micro-fins in microchannels were designed, and then, mixture model was used to simulate the Al 2 O 3 –water nanofluids, which was followed by establishing a CFD model to investigate the effects of different micro-fins on the flow and heat transfer properties in microchannels. Results show that microchannels with micro-fins were significantly superior to smooth ones, achieving higher Nusselt numbers (Nu). The isosceles triangular micro-fin exhibits the highest Nu and reduced pressure drops by up to 16.1% compared to the rectangular micro-fin. Field synergistic theory analysis revealed that microchannels with isosceles triangular and trapezoidal micro-fins achieved the greatest reduction in synergistic angles, indicating improved synergy between flow and heat transfer.

Graphoepitaxy provides a robust route to align lamellar block copolymers in topographic trenches, yet alignment often degrades rapidly as the trench width increases into the wide-trench regime. Here, mesoscale density functional simulations under thermal annealing are used to quantify width- and geometry-dependent ordering of symmetric lamella-forming block copolymers confined in trenches. A Fourier-based alignment metric reveals a sharp, sigmoidal decay of alignment with trench width normalized by the natural lamellar period, indicating a crossover between (i) a globally aligned state established by wall-guided propagation and (ii) a misoriented, kinetically trapped state produced by bulk-like interior nucleation followed by domain impingement. This width dependence is well captured by a logistic form, yielding a characteristic crossover width and transition sharpness that compactly describe the accessible alignment window. Parameter sweeps show that increasing incompatibility shifts the crossover to smaller widths, whereas stronger sidewall surface fields extend the accessible width range with diminishing returns at large fields; in the range examined, film thickness has little influence on the crossover. Finally, simulations in trapezoidal trenches demonstrate that high alignment persists for moderate sidewall taper, while larger taper promotes lamellar bending and defects. A geometric criterion based on the variation in trench width across the film thickness, using a numerical threshold derived from strong-segregation theory, rationalizes the observed onset of degradation when this variation approaches approximately 1.4 lamellar periods. These results provide a mechanistic framework and quantitative guidelines for extending graphoepitaxial lamellar alignment beyond the narrow-confinement regime.

This paper presents an investigation on the flame height of rectangular pool fires bounded by a sidewall. A series of experiments were conducted to investigate the flame height of pool fire bounded by a sidewall with different distances and aspect ratios. Four pools with identical area but different aspect ratios of 1:1, 1:2, 1:4, and 1:8 are studied. Experimental results show that flame height is strongly related to the distance between the fire source and the sidewall and the aspect ratio. The flame height increases with the decreases in the distance and the aspect ratio. A hydraulic diameter has been conducted to develop a correlation for calculating the total flame height. One more hydraulic diameter has been assumed to develop the correlation for the height of flame attached to the sidewall.

Carbon black-reinforced rubber compounds based on the blends of natural rubber (NR) and butadiene rubber (BR) for tire sidewall applications were formulated to investigate the self-healing efficacy of a modifier called EMZ. This modifier is based on epoxidized natural rubber (ENR) modified with hydrolyzed maleic anhydride (HMA) as the ester crosslinking agent plus zinc acetate dihydrate (ZAD) as the transesterification catalyst. The influence of EMZ modifier content in sidewall compounds on processing characteristics, reinforcement, mechanical and fatigue properties, as well as property retentions, was investigated. Increasing the content of EMZ, the dump temperatures and Mooney viscosities of the compounds slightly increase, attributed to the presence of extra polymer networks and filler–rubber interactions. The bound rubber content and Payne effect show a good correction that essentially supports that the EMZ modifier gives enhanced filler–rubber interaction and reduced filler–filler interaction, reflecting the improved homogeneity of the composites. This is the key contribution to a better flex cracking resistance and a high fatigue-to-failure resistance when utilizing the EMZ modifier. To validate the property retentions, molecular damages were introduced to vulcanizates using a tensile stress–strain cyclic test following the Mullins effect concept. The property retentions are significantly enhanced with increasing EMZ content because the EMZ self-healing modifier provides reversible or dynamic ester linkages that potentially enable a bond-interchange mechanism of the crosslinks, leading to the intermolecular reparation of the rubber network.

Radio Frequency Micro Electro Mechanical System (RF MEMS) switches are rapidly evolving due to the demand for low cost, high performance, and compact communication systems. An electrothermally actuated bistable lateral MEMS switch for redundancy applications has been already fabricated and tested for mechanical characteristics. In this paper to make this switch as a suitable candidate for RF applications,sidewall metallization using gold is proposed.Modelling of sidewall metallization in Bistable Lateral RF MEMS switch using Cascade Feedforward Scaled Conjugate Gradient (CFSCG) Artificial Neural Network approach is reported. Using an inverse approach of ANN, the desired length of sidewall coating required for better RF performance in terms of return loss and insertion loss is predicted. Time-consuming optimization procedures to determine the sidewall coating in customized EM simulators such as HFSS have been overcome using the proposed CFSCG approach. In this paper, the proposed CFSCG approach reduces the design time of the switch with sidewall coating by 99.4048% compared to the conventional EM simulator which takes approximately 14 h. Validation is done by comparing the obtained results with the HFSS model and good agreement is obtained. The simulation of the proposed switch results in an insertion loss less than -1 dB in the frequency range between 1-10 GHz with gold sidewall metallization of bistable lateral RF MEMS switch.

An experimental study on the characteristics of downward flame spread of extruded polystyrene (XPS) is presented. The parameters investigated include average mass loss rate per unit of thickness ( m ˙ ′ ), average flame height ( H f ), average flame spread rate ( v f ), and mass growth rate ( m ˙ 1 ) of molten XPS. The effects of sample thickness ( d ), sidewalls and atmospheric pressure ( p ), and the combined effects of these factors on the flame spread are studied. The larger sample thickness corresponds to larger m ˙ ′ and higher flame upon most occasions. As d rises, v f and m ˙ 1 increase under all conditions; v f and d follow the equation: v f = A ( 1 - exp( - Cd)) . The dimensionless heat release rate: Q ˙ ∗ ∝ exp ( - 0.3 d ) . m ˙ ′ , v f , and m ˙ 1 obtained without sidewalls are higher than those with sidewalls. m ˙ ′ , v f, and H f obtained on the plain ( p  = 100.8 kPa) are larger than those obtained on the plateau ( p  = 65.5 kPa). m ˙ 1 obtained on the plain is lower than that on the plateau. In most cases without sidewalls, m ˙ ∝ p n 0 , where 1.9 <  n 0  < 2, and H f = a + μ p n 0 . H f obtained in the cases without sidewalls is larger than that with sidewalls when the sample thickness is small, while the opposite is true for thicker samples. When sidewalls are absent, on the plain, with a rise in thickness, the increase of v f is significant for thin samples while the variation is not considerable for thick samples; on the plateau, this increase is significant for all thicknesses tested. The experimental results agree well with the theoretical analysis.