Flammability evaluation of clean room polymeric materials for the semiconductor industry

A new methodology, identified as the 4910 Test Protocol, has been developed to evaluate the fire propagation and smoke development behaviour of polymeric materials for use in clean rooms for the semiconductor industry. This paper reviews the scientific basis of the concepts and criteria contained in the 4910 Test Protocol. For the acceptance of polymeric materials, two criteria are used: (a) Fire Propagation Index (FPI) ⩽6 (ms^−1/2)/(kWm⁻¹)^2/3 and (b) Smoke Development Index (SDI) ⩽0.4 (gg⁻¹) (ms^−1/2)/(kWm⁻¹)^2/3. Materials are tested in the ASTM E 2058 Fire Propagation Apparatus (previously identified as the Factory Mutual Research Flammability Apparatus). The Fire Propagation Index (FPI) is formulated from: (a) the Thermal Response Parameter (TRP), which relates the time‐to‐ignition to the net heat flux to the sample surface, and (b) the chemical heat release rate measured during the upward fire propagation in air having a 40% oxygen concentration to simulate flame heat transfer at large scale. The SDI is related to the smoke release rate and is obtained by multiplying the FPI value by the smoke yield. The smoke yield is defined as the ratio of the total mass of smoke released per unit mass of the vapours of the polymeric material burned. Small and large‐scale fire test data have been included in the paper in support of the 4910 Test Protocol criteria. Highly halogenated and high temperature specialty polymeric materials and highly modified ordinary thermoplastics are found to satisfy the criteria. Copyright © 2001 John Wiley & Sons Ltd.     

Tubular Assembly Formation Induced by Leucine Alignment along the Hydrophobic Helix of Amphiphilic Polypeptides

The introduction of α-helical structure with a specific helix–helix interaction into an amphipathic molecule enables the determination of the molecular packing in the assembly and the morphological control of peptide assemblies. We previously reported that the amphiphilic polypeptide SL12 with a polysarcosine (PSar) hydrophilic chain and hydrophobic α-helix (l-Leu-Aib)₆ involving the LxxxLxxxL sequence, which induces homo-dimerization due to the concave–convex interaction, formed a nanotube with a uniform 80 nm diameter. In this study, we investigated the importance of the LxxxLxxxL sequence for tube formation by comparing amphiphilic polypeptide SL4A4L4 with hydrophobic α-helix (l-Leu-Aib)₂-(l-Ala-Aib)₂-(l-Leu-Aib)₂ and SL12. SL4A4L4 formed spherical vesicles and micelles. The effect of the LxxxLxxxL sequence elongation on tube formation was demonstrated by studying assemblies of PSar-b-(l-Ala-Aib)-(l-Leu-Aib)₆-(l-Ala-Aib) (SA2L12A2) and PSar-b-(l-Leu-Aib)₈ (SL16). SA2L12A2 formed nanotubes with a uniform 123 nm diameter, while SL16 assembled into vesicles. These results showed that LxxxLxxxL is a necessary and sufficient sequence for the self-assembly of nanotubes. Furthermore, we fabricated a double-layer nanotube by combining two kinds of nanotubes with 80 and 120 nm diameters—SL12 and SA2L12A2. When SA2L12A2 self-assembled in SL12 nanotube dispersion, SA2L12A2 initially formed a rolled sheet, the sheet then wrapped the SL12 nanotube, and a double-layer nanotube was obtained.     

Sphingomyelin metabolism is linked to salt transport in the gills of euryhaline fish

Byin vivo andin vitro studies ofl-(3-³H)serine and [9,10(n)-³H]palmitic acid incorporation into phospholipids, we show a change in the renewal of the ceramide moiety of sphingomyelin in the gills of euryhaline fish (sea bass and eels) when the animals were subjected to abrupt alterations in environmental salinity.In vivo, decrease of the salinity from sea water (salinity 3.7%) to diluted sea water (salinity 1%) induced an increase of label incorporation into gill sphingomyelin. The same was true when gills from sea water-adapted sea bass or sea water-adapted eels were incubated in diluted sea water. A decrease in free ceramides synthesis was also observed in the gills of sea water-adapted sea bass when the salinity of the incubation medium was reduced. Direct inhibition of Na⁺/K⁺-ATPase activity with ouabain decreased the sphingomyelin synthesis in the gills of sea bass duringin vitro incubation in diluted sea water, whereas treatment with furosemide stimulated sphingomyelin synthesis in the same gills incubated in sea water. These findings indicate that changes in Na⁺ fluxes modify the sphingomyelin turnover and control the production of free ceramides and sphingosine in gill cells of euryhaline fish. In view of the well-known effects of these sphingomyelin degradation products on isolated tumor cell differentiation, we suggest that they play a very important role in modulating chloride cell distribution and metabolism of fish gills during abrupt changes in environmental salinity.     

Optimal Natural Convection Heat Transfer Improvement by Combining Periodic Heating Temperature,Cavity Inclination,and Nanofluid

Natural convection within a square inclined cavity filled with Al₂O₃–water nanofluid is investigated numerically. The temperature of the cooled surface is maintained constant, while that of the opposite surface (heating temperature) is varied sinusoidally in time. The remaining walls are considered adiabatic. The parameters governing the problem are the amplitude and the period of the variable temperature, the Rayleigh number, the inclination of the cavity, and the solid volume fraction. A substantial enhancement of heat transfer is obtained by combining the beneficial effects of the variable heating temperature (via its period and amplitude), the inclination of the cavity, and the nanoparticles fraction. In comparison with the constant heating conditions, it is found that both the variable heating temperature and the inclination of the cavity may lead to drastic changes in the flow structure and the corresponding heat transfer. The resonance phenomenon, observed for critical periods of the exciting temperature, is amplified by adding Al₂O₃ nanoparticles to the base fluid.     

A hybrid mobile object tracker based on the modified Cuckoo Search algorithm and the Kalman Filter

Most revolutionary algorithms are inspired from the behavior of natural species. This inspiration can be drawn from their reproductive behavior, flying mode, or even their ways of communication. One of the most efficient metaheuristics in a discrete search space is the Cuckoo Search algorithm, inspired by the Cuckoo?s reproductive behavior and combined with the Lévy flight pattern adopted by many animals and insects. In this paper, we present a new tracking approach, the Hybrid Kalman Cuckoo Search tracker, using a modified version of the Cuckoo Search algorithm combined with the well-known Kalman Filter. The Cuckoo Search algorithm is combined with the prediction step adopted by the Kalman Filter to enhance the initial population?s quality. Using the Hybrid Kalman Cuckoo Search tracker, we can efficiently explore the search space in order to locate an object?s position from one frame to the next. The Lévy flight model is also modified in order to re-adapt the Lévy step size as the algorithm approaches the desired solution. The Hybrid Kalman Cuckoo Search tracker is tested on a variety of datasets including one where we incorporated different situations, as well as some videos from the CAVIAR, SPEVI, and other datasets. The comparative study results show that the proposed algorithm outperforms the Particle Swarm Optimization based tracker, especially in terms of computation time.     

Application of NIR hyperspectral imaging for discrimination of lamb muscles

The potential of near-infrared (NIR) hyperspectral imaging system coupled with multivariate analysis was evaluated for discriminating three types of lamb muscles. Samples from semitendinosus (ST), Longissimus dorsi (LD) and Psoas Major (PM) of Charollais breed were imaged by a pushbroom hyperspectral imaging system with a spectral range of 900-1700 nm. Principal component analysis (PCA) was used for dimensionality reduction, wavelength selection and visualizing hyperspectral data. Six optimal wavelengths (934, 974, 1074, 1141, 1211 and 1308 nm) were selected from the eigenvector plot of PCA and then used for discrimination purpose. The results showed that it was possible to discriminate lamb muscles with overall accuracy of 100% using NIR hyperspectral reflectance spectra. An image processing algorithm was also developed for visualizing classification results in a pixel-wise scale with a high overall accuracy.     

Isomer‐Pure Bis‐PCBM‐Assisted Crystal Engineering of Perovskite Solar Cells Showing Excellent Efficiency and Stability

A fullerene derivative (α‐bis‐PCBM) is purified from an as‐produced bis‐phenyl‐C₆₁‐butyric acid methyl ester (bis‐[60]PCBM) isomer mixture by preparative peak‐recycling, high‐performance liquid chromatography, and is employed as a templating agent for solution processing of metal halide perovskite films via an antisolvent method. The resulting α‐bis‐PCBM‐containing perovskite solar cells achieve better stability, efficiency, and reproducibility when compared with analogous cells containing PCBM. α‐bis‐PCBM fills the vacancies and grain boundaries of the perovskite film, enhancing the crystallization of perovskites and addressing the issue of slow electron extraction. In addition, α‐bis‐PCBM resists the ingression of moisture and passivates voids or pinholes generated in the hole‐transporting layer. As a result, a power conversion efficiency (PCE) of 20.8% is obtained, compared with 19.9% by PCBM, and is accompanied by excellent stability under heat and simulated sunlight. The PCE of unsealed devices dropped by less than 10% in ambient air (40% RH) after 44 d at 65 °C, and by 4% after 600 h under continuous full‐sun illumination and maximum power point tracking, respectively.     

Efficiency Effect of Obstacle Margin on Line-of-Sight in Wireless Networks

Line-of-sight clarity and assurance are essential because they are considered the golden rule in wireless network planning, allowing the direct propagation path to connect the transmitter and receiver and retain the strength of the signal to be received. Despite the increasing literature on the line of sight with different scenarios, no comprehensive study focuses on the multiplicity of parameters and basic concepts that must be taken into account when studying such a topic as it affects the results and their accuracy. Therefore, this research aims to find limited values that ensure that the signal reaches the future efficiently and enhances the accuracy of these values’ results. We have designed MATLAB simulation and programming programs by Visual Basic .NET for a semi-realistic communication system. It includes all the basic parameters of this system, taking into account the environment's diversity and the characteristics of the obstacle between the transmitting station and the receiving station. Then we verified the correctness of the system's work. Moreover, we begin by analyzing and studying multiple and branching cases to achieve the goal. We get several values from the results, which are finite values, which are a useful reference for engineers and designers of wireless networks.     

Proteomics Profiling of Osteoporosis and Osteopenia Patients and Associated Network Analysis

Bone mass reduction due to an imbalance in osteogenesis and osteolysis is characterized by low bone mineral density (LBMD) and is clinically classified as osteopenia (ON) or osteoporosis (OP), which is more severe. Multiple biomarkers for diagnosing OP and its progression have been reported; however, most of these lack specificity. This cohort study aimed to investigate sensitive and specific LBMD-associated protein biomarkers in patients diagnosed with ON and OP. A label-free liquid chromatography-mass spectrometry (LC-MS) proteomics approach was used to analyze serum samples. Patients’ proteomics profiles were filtered for potential confounding effects, such as age, sex, chronic diseases, and medication. A distinctive proteomics profile between the control, ON, and OP groups (Q² = 0.7295, R² = 0.9180) was identified, and significant dysregulation in a panel of proteins (n = 20) was common among the three groups. A comparison of these proteins showed that the levels of eight proteins were upregulated in ON, compared to those in the control and the OP groups, while the levels of eleven proteins were downregulated in the ON group compared to those in the control group. Interestingly, only one protein, myosin heavy chain 14 (MYH14), showed a linear increase from the control to the ON group, with the highest abundance in the OP group. A significant separation in the proteomics profile between the ON and OP groups (Q² = 0.8760, R² = 0.991) was also noted. Furthermore, a total of twenty-six proteins were found to be dysregulated between the ON and the OP groups, with fourteen upregulated and twelve downregulated proteins in the OP, compared to that in the ON group. Most of the identified dysregulated proteins were immunoglobulins, complement proteins, cytoskeletal proteins, coagulation factors, and various enzymes. Of these identified proteins, the highest area under the curve (AUC) in the receiver operating characteristic (ROC) analysis was related to three proteins (immunoglobulin Lambda constant 1 (IGLC1), RNA binding protein (MEX3B), and fibulin 1 (FBLN1)). Multiple reaction monitoring (MRM), LC-MS, was used to validate some of the identified proteins. A network pathway analysis of the differentially abundant proteins demonstrated dysregulation of inflammatory signaling pathways in the LBMD patients, including the tumor necrosis factor (TNF), toll-like receptor (TL4), and interferon-γ (IFNG) signaling pathways. These results reveal the existence of potentially sensitive protein biomarkers that could be used in further investigations of bone health and OP progression.