Analysis of frost visualization over a fin and tube heat exchanger by natural convection

In this article, studies are made on frost formation and flow over a fin and tube heat exchanger due to natural convection for various conditions of relative humidity, air ambient temperature, and mean refrigerant temperature. The results include frost deposition, steps of frost formation, and its effect on heat transfer rate for different conditions. The results show that frost is formed only on the tip of the fins with higher thickness from top to bottom due to small distance between the fins. Frost causes to trap the air which increases the thermal resistance and reduces heat transfer in the system.     

Ultrasonic assisted improved extraction and dyeing of mordanted silk fabric using neem bark as source of natural colourant

Natural products with therapeutic nature are nowadays warmly welcomed in textiles. Current study is concerned with isolation of tannin from neem bark (Azadirachta indica) and its application onto silk fabric. For improvement in shades, chemical & bio-mordants have been employed at optimal dyeing conditions. It is found that methanolic extract of pH 5 obtained 8 g dye powder after US Treatment for 30 min has given high color strength if used to dye irradiated silk for 65 min at 75 °C. Bio-mordanting using herbal plants has improved the color characteristics as compared to chemical mordants used. ISO standards for color fastness reveal that herbal based bio-mordants have improved the rating from good to excellent as compared to chemical mordants used. It is concluded that US treatment has not only isolate the colorant for neem bark under mild condition but also given excellent characteristic using bio mordants onto silk fabrics.     

Association study of the angiotensin-converting enzyme (ACE) gene G2350A dimorphism with myocardial infarction

The angiotensin converting enzyme (ACE) is a strong candidate gene for myocardial infarction (MI). Insertion-deletion dimorphism in intron 16 of this gene has been inconclusively found to be associated with it. Several new polymorphisms in the ACE gene have been identified and among these, a dimorphism in exon 17, ACE G2350A, has a significant effect on plasma ACE concentrations. To assess the value of genotyping the ACE G2350A dimorphism in a genetically homogeneous population, we carried out a case-control study of dimorphism G2350A for a putative association with MI among Pakistani nationals. We investigated a sample population of 370 Pakistanis, comprising 163 controls, and 207 patients with clinical diagnosis of acute MI (AMI). ACE G2350A alleles were visualized by assays based on polymerase chain reaction and restriction endonuclease analysis. Frequencies of G alleles were 0.68 among controls and 0.72 among AMI patients. The ACE G2350A dimorphism showed no significant association with MI (chi2 = 0.90, 2 df, P = 0.64), plasma levels of homocysteine (P = 0.52) or with serum levels of folate (P = 0.299). The results indicate that ACE G2350A polymorphism is not associated with risk of myocardial infarction in the Pakistani population investigated here.     

A mechanism and kinetics of discharge pumped mercury bromide lasers

Emission spectra of the HgBr (B²Σ⁺-Z ²Σ⁺) band system and atomic mercury lines observed during collisions of HgBr₂ with N⁺/N₂⁺ ions at different laboratory kinetic energies are discussed. Emission cross sections of the most intense band of the HgBr transition at 502 nm have been measured at low energies of the projectile ions. Collision-induced dissociative excitation processes appear to be the dominant mechanism producing these emissions     

Propagation of Chirped Non-Linear Pulses in a Lossy Highly Birefringent Single-Mode Optical Fibre

A new model of the non-linear propagation of optical solitons with initial linear frequency chirp through lossy highly birefringent fibres, allowing the improvement of the practical results concerning the distortionless signal transmission in ultra-high-speed communications, is presented within the framework of a system of coupled non-linear Schrödinger (CNLS) equations. This model demonstrates the existence of bound chirped solitons in a lossy single-mode highly briefringent fibre.     

Structural Detail and Thermal Bond Relocation of a Sterically Strained Cyclononatetraene Preliminary Communication

The X-ray crystallographic molecular dimensions and thermal response of the 5, 13-diphenyl-cyclonoa [b]naphthalene 1a , are described.     

Observation of the Omega(0)(c) Charmed Baryon at CLEO

The CLEO experiment at the CESR collider has used 13.7 fb(-1) of data to search for the production of the Omega(0)(c) (css ground state) in e(+)e(-) collisions at square root of (s) approximately 10.6 GeV. The modes used to study the Omega(0)(c) are Omega(-)pi(+), Omega(-)pi(+)pi(0), Xi-K-pi(+)pi(+), Xi0K-pi(+), and Omega(-)pi(+)pi(+)pi(-). We observe a signal of 40.4+/-9.0(stat) events at a mass of 2694.6+/-2.6(stat)+/-1.9(syst) MeV/c(2), for all modes combined.     

Classical versus reinforcement learning algorithms for unmanned aerial vehicle network communication and coverage path planning: A systematic literature review

The unmanned aerial vehicle network communication includes all points of interest during the coverage path planning. Coverage path planning in such networks is crucial for many applications, such as surveying, monitoring, and disaster management. Since the coverage path planning belongs to NP-hard issues, researchers in this domain are constantly looking for optimal solutions for this task. The speed, direction, altitude, environmental variations, and obstacles make coverage path planning more difficult. Researchers have proposed numerous algorithms regarding coverage path planning. In this study, we examined and discussed existing state-of-the-art coverage path planning algorithms. We divided the existing techniques into two core categories: Classical and reinforcement learning. The classical algorithms are further divided into subcategories due to the availability of considerable variations in this category. For each algorithm in both types, we examined the issues of mobility, altitude, and characteristics of known and unknown environments. We also discuss the optimality of different algorithms. At the end of each section, we discuss the existing research gaps and provide future insights to overcome those gaps.