The Effect of Copper and Brass on Friction Stir Welded Dissimilar Aluminium Alloy When Used in Thin Sheet Form

In recent year’s aluminium and aluminium alloys are most widely used in many applications because of light weight, good formability and malleability, corrosion resistance, moderate strength and low cost. Friction Stir Welding (FSW) process is an efficient and cost-effective method for welding aluminium and aluminium alloys. FSW is a solid-state welding process that means the material is not melted during the process. Complete welding process accomplishes below the melting point of materials so it overcomes many welding defects that usually happens with conventional fusion welding technique which was initially used for low melting materials. Though this process is initially developed for low melting materials but now the process is widely used for a variety of other materials including titanium, steel and also for composites. The present butt jointed FSW experimental work has been done in two ways. Initially, a comparison of tensile properties of friction stir (FS) welded similar aluminium alloy (AA6351 with AA6351) and dissimilar aluminium alloy (AA6351 with AA5083) combinations. Later the effect of impurities (copper and brass) in sheet form (0.1 mm thick) when used as an insert in between two dissimilar aluminium (AA6351 with AA5083) alloy plates during FSW. Tensile tests were performed for these combinations and results were compared for with and without using strip material (copper and brass)

Floods and flood management and its socio-economic impact on Pakistan: A review of the empirical literature

Flood is one of the most damaging natural disasters as the recent floods have shown their serious impact on Pakistan. Flood control and regulation policies are essential to reduce the risks of economic downturn, a threat to human existence, and to sustain the ecology. The severity of flood catastrophe activities represents a constant and severe issue in the world. Floods are rising year by year in severity and duration, causing negative impacts on the social and economic conditions of the nation concerned. While the frequency of floods cannot be avoided, their adverse impacts can be considerably reduced by adopting careful planning and efficient training. This paper reviews the socioeconomic impact of floods, and the existing condition of flood control policies outlines the flood protection problems and discusses opportunities for successful and efficient flood control in Pakistan. The paper also intends to propose several suggestions for efficient and sustainable flood control in Pakistan

Study of Coefficient of Friction and Springback Analysis of Brass in Bendingat Elevated Temperature Conditions

In the present work, finite element analysis is carried out for the minimization of springback in theV-bending process for high-strength brass sheet metal. Firstly, the uniaxial tensile test is conducted to determine the variousmaterial properties required for finite element analysis. The various test parameters considered in the V-Bending process aretemperature (573 K, 673 K and 773K), punch speeds (1 mm/min, 5 mm/min and 10 mm/min), holding time (30 s, 60 s and90 s) and sheet orientation concerning rolling direction RD (00), ND (450) and TD (900) for finite element analysis. Thebending under tension test is used to determine the coefficient of friction at different temperatures and lubricationconditions, and these values are implemented in finite element simulations of the V-bending process. Taguchi analysis iscarried out to determine springback of high-strength brass alloy by selecting four control factors (temperature, punch speed,holding time, and orientation). From the analysis of the signal-to-noise (S/N) ratio, it is reported that the temperature(46.93%) is the most significant parameter which influences the springback followed by holding time (26.29%), sheetorientation (24.07%) and punch speed (2.69%). The optimal set obtained for the minimum springback of brass alloy and theconformation test is performed at the optimum set conditions (773 K temperature, 1 mm/min punch speed, 90 s holdingtime, and 90° to the rolling direction of a sheet). With the optimal set of process parameters, Springback decreasedsignificantly to around 68.68%. Through the investigation of springback analysis, it is directly proportional to thetemperature and holding time and inversely proportional to the punch speed, but sheet orientation doesn’t follow any trends

Gazella bennetti (indian gazelle or chinkara) of Pakistan: genetic profiling and conservation priorities

Indian gazelle is endemic to wild northern Punjab, Pakistan, and also an endangered species according to red list categories of International Union of Conservation of Nature and Natural Resources. Better understanding of genetics of immune response of this species can be helpful to design effective conservation strategies. The objective of this study was to assess the molecular genetic diversity on interleukin 2 (IL-2) gene sequences of endangered G. bennetti as a gene encoding a cytokine involved in some vital activities of immune response regulation. The IL-2 gene (492 bp) was amplified and sequenced in DNA samples collected from wild as well as captive indian gazelle, followed by alignment and phylogenetic analysis. The neighbour joining tree constructed from MEGA6 showed that G. bennetti is differ from others and form in a different clade. The analysis of study results showed that indian gazelle is a unique isolated population found in Pakistan which is endemic as well as endangered. Therefore, in-situ and ex-situ conservation techniques for G. bennetti present a good solution to preserve this endangered species from extinction.La gacela india es oriunda de la zona silvestre del norte de Pendjab (Pakistán). De acuerdo a las categorías de la lista roja de la Unión Internacional de Conservación de la Naturaleza y los Recursos Naturales, constituye una especie en peligro. El entendimiento de la genética de la respuesta inmune en esta especie puede ser útil para diseñar efectivas estrategias de conservación. El objetivo del estudio fue evaluar la diversidad genética molecular en la interleukina 2 (IL-2), secuencias de genes que ponen en peligro a G. bennetti como un gen que codifica una citokina involucrada en algunas actividades vitales de regulación de la respuesta inmune. El gen IL-2 (492 bp) fue amplificado y secuenciado en muestras de ADN colectadas de la naturaleza, así como de ejemplares cautivos de gacela india, seguidos por la alineación y el análisis filogenético. Los vecinos que unen el árbol construido de MEGA6 mostraron que G. bennetti es distinto de otros y forma un clado diferente. El análisis de los resultados del estudio mostró que las gacelas indias constituyen una única población aislada encontrada en Pakistán, la cual es endémica y está expuesta al peligro. Por consiguiente, las técnicas de conservación in-situ y ex-situ para G. bennetti constituyen una buena alternativa para evitar el peligro de extinción de la especie

Thermal, electrochemical and mechanical properties of shape memory alloy developed by a conventional processing route

A Cu based shape memory alloy (Cu-Al-Ni) having a composition 83% Cu, 14% Al, 3% Ni, was developed and studied to determine the shape memory effect. Powder of Cu, Al and Ni was melted in a pit furnace at about 15500C, and casted alloy was heat treated at 8500C for a period of 50 minutes followed by water quenching. Microstructure characterization of alloy (Cu-Al-Ni) was carried out to determine the pre-quenched (cast structure) and quenched martensitic structure. The microstructure analysis of developed samples showed needle like structure of quenched martensite after heat treatment. It has a very good resemblance with structure of casted shape memory alloy obtained from the vacuum induction process. The Vickers hardness test was also performed. Quenched microstructure with improved hardness than pre-quenched structure was observed.Keywords: Shape Memory Alloy, Microstructure, Mechanical Propertie

Thermoelectric Properties of Oxide Semiconductors

In this chapter, we have explored the potential of oxide semiconductors for thermoelectric power generation. Various oxides (Cu2InO4, CuAlO2, and Zn2GeO4) were grown on Si substrate by thermal evaporation method using tube furnace. After the growth, a representative sample of each oxide was cut into pieces and was annealed at various temperatures from 600 to 800°C in oxygen environment for 1 h using a programmable furnace. The structure of all annealed sample was verified by performing X-ray powder diffraction (XRD) measurements. XRD data suggested that all oxide materials show crystalline behavior at annealing temperature 800°C. XRD results further confirmed that crystal structure of investigated samples improved significantly with annealing because the intensity of oxygen-sensitive (0 0 6) plane was found to be increased with annealing temperature. To investigate the thermoelectric properties of annealed samples, Seebeck effect and Hall effect measurements were performed in the temperature range 25–100°C. It was found that the value of Seebeck coefficient and power factor increased as the annealing temperature increases. Zn2GeO4 was found to be a potential thermoelectric material because it has the highest value of Seebeck coefficient and power factor. This highest value is related to the presence of secondary phases in this oxide

Physico-chemical characteristics of seed oils extracted from different apricot (<i>Prunus armeniaca</i> L.) varieties from Pakistan

The fruit seed oils from four varieties of apricot (<i>Prunus armeniaca</i> L.), namely, Halmas, Nari, Travet and Charmagzi were analyzed for different physico-chemical characteristics. The oil yield from the apricot seeds (kernels) ranged from 32.23-42.51%, while the protein, fiber and ash contents ranged from 13.21-20.90%, 5.13-9.81% and 2.11-3.89%, respectively. The extracted oils had an average iodine value (g of I/100 g of oil) of 96.4-106.3; density at 24 °C, 0.87-0.93 mg/mL; refractive index (40 °C), 1.4655-1.4790; saponification value, 189.1-199.4 mg of KOH/g oil; unsaponifiable matter, 0.59-0.88%; free fatty acid (mg of KOH/g oil), 0.41-1.28; and color (1-inch cell), 1.31-2.96R 1 14.8-29.8Y. With regard to the oxidation state, the tested oils showed values for specific extinction at 232 and 268 nm, 2.30-3.42 and 0.82-1.04, respectively, while the peroxide value was 1.0-2.32 meq O2/kg and, p-anisidine was 1.22-1.90. The major fatty acid found in the oils was oleic acid (62.34-80.97%) followed by linoleic (13.13-30.33%), palmitic (3.35-5.93%), linolenic (0.73-1.03%) and stearic (1.10-1.68%) acids. The contents of α-, γ-, and δ-, tocopherols in the oils ranged from 14.8-40.4, 330.8-520.8 and 28.5-60.2 mg/kg, respectively. The results of our present investigation revealed that apricot seed is a potential source of oil which can be used both for edible and oleochemical applications.<br><br>Se han analizado las características físico-químicas de aceites de semillas de frutos de cuatro variedades diferentes de albaricoque, Halmas, Nari, Travet y Charmagzi (Prunus <i>armeniaca</i> L.). La producción de aceites de las semillas de albaricoque (hueso) osciló entre 32,23-42,51%, mientras que las proteínas, fibra y cenizas dieron valores de 13,21-20,90%, 5,13-9,81% y 2,11-3,89%, respectivamente. Los aceites extraídos presentaron valores promedio de índice de yodo, de 96,4-106,3 (g de I/100 g de aceite); densidades a 24 °C de 0,87-0,93 mg/mL, índices de refracción (40 °C) de 1,4655- 1,4790; índices de saponificación de 189.1-199,4 (mg KOH/g de aceite), materia insaponificable de 0,59-0,88%, valores de acidez libre de 0.41-1.28 (mg de KOH /g de aceite), y valores de color de 1,31-2.96R 14,8-29,8Y (celda de 1 pulgada). Con respecto al estado de oxidación de los aceites estudiados, estos mostraron valores de extinción específica a 232 y 268 nm de 2,30-3,42 y 0,82-1,04, respectivamente, mientras que dieron valores de índices de peróxidos de 1,0-2,32 meq O2/kg y de p-anisidina de 1,22-1,90. El principal ácido graso que se encuentra en los aceites fue el ácido oleico (62,34 -80,97%), seguido de linoleico (13,13-30,33%), palmítico (3,35-5,93%), linolénico (0,73 - 1,03%) y esteárico (1,10 a 1,68%). El contenido de α-, γ- y δ- tocoferoles en los aceites variaron desde 14,8 hasta 40,4, 330,8 a 520,8 y 28,5 hasta 60,2 mg/kg, respectivamente. Los resultados de nuestra investigación actual revela que la semilla de albaricoque es una fuente potencial de aceite que puede ser utilizado tanto para aplicaciones comestibles como oleoquímicas

Epidemiology and risk factors for pneumonia severity and mortality in Bangladeshi children <5 years of age before 10-valent pneumococcal conjugate vaccine introduction

Abstract Background Pneumonia is the leading infectious cause of morbidity and mortality in young children in Bangladesh. We present the epidemiology of pneumonia in Bangladeshi children <5 years before 10-valent pneumococcal conjugate vaccine introduction and investigate factors associated with disease severity and mortality. Methods Children aged 2–59 months admitted to three Bangladeshi hospitals with pneumonia (i.e., cough or difficulty breathing and age-specific tachypnea without danger signs) or severe pneumonia (i.e., cough or difficulty breathing and ≥1 danger signs) were included. Demographic, clinical, laboratory, and vaccine history data were collected. We assessed associations between characteristics and pneumonia severity and mortality using multivariable logistic regression. Results Among 3639 Bangladeshi children with pneumonia, 61% had severe disease, and 2% died. Factors independently associated with severe pneumonia included ages 2–5 months (adjusted odds ratio [aOR] 1.60 [95% CI: 1.26–2.01]) and 6–11 months (aOR 1.31 [1.10–1.56]) relative to 12–59 months, low weight for age (aOR 1.22 [1.04–1.42]), unsafe drinking water source (aOR 2.00 [1.50–2.69]), higher paternal education (aOR 1.34 [1.15–1.57]), higher maternal education (aOR 0.74 [0.64–0.87]), and being fully vaccinated for age with pentavalent vaccination (aOR 0.64 [0.51–0.82]). Increased risk of pneumonia mortality was associated with age <12 months, low weight for age, unsafe drinking water source, lower paternal education, disease severity, and having ≥1 co-morbid condition. Conclusions Modifiable factors for severe pneumonia and mortality included low weight for age and access to safe drinking water. Improving vaccination status could decrease disease severity