Method of characteristics and solution of DGLAP evolution equation in leading order (LO) and next to leading order (NLO) at small-x

In this paper the singlet and non-singlet structure functions have been obtained by solving Dokshitzer, Gribove, Lipatov, Alterelli, Parisi (DGLAP) evolution equations in leading order (LO) and next to leading order (NLO) at the small x limit. Here we have used a Taylor Series expansion and then the method of characteristics to solve the evolution equations. We have also calculated t and x-evolutions of deuteron structure function and the results are compared with the New Muon Collaboration (NMC) data.Comment: 16 pages including 7 figure

Investigation into how the floor plan layout of a manufactured PCB influences flip-chip susceptibility to vibration

This article investigates how floor plan layout of a printed circuit board (PCB) influences the reliability of the component's solder joint connections when operated in a vibrating environment. A random vibration profile as seen in an automotive environment was used in full lifetime tests. An industry-standard FR4 PCB with electroless nickel immersion gold (ENIG) surface finish was manufactured with double-sided component placement including 14 flip chips, eight on the top side and six on the bottom side. Ultrasound scans were used as a nondestructive test to assess the integrity of solder joints from manufacture to failure. This enabled monitoring of the important interface between solder joints and flip chip where failure mostly occurs. The initial failure pattern was found by experiment where 86 cycles of random vibration caused all flip chips to mechanically fail. Failure followed a Weibull probability with a value of β = 1.297, indicating that failure rates increase with time. The results show that the reliability of a flip chip varies with its position on a PCB with some marked differences to component lifetimes. The results also show that for two-sided flip-chip placements on a PCB, back-to-back, overlapped, and single-sided orientations have subtle effects on flip-chip lifetimes. Similarly, reliability varied with solder joint positions since joints on the sides of a flip chip nearest the PCB edges were less reliable than those on sides on a flip chip furthest away. Finally, design guidelines are offered to effect the most reliable flip-chip placement on a two-sided PCB when operated in a vibrating environment. © 2011-2012 IEEE

An efficient reduction protocol for the synthesis of beta-hydroxycarbamates from beta-nitro alcohols in one pot : a facile synthesis of (-)-beta-conhydrine

An efficient and practical one-pot protocol for the reduction of b-nitro alcohols to their corresponding N-(tert-butoxycarbonyl) amino alcohols using Zn 13NH4Cl in aqueous methanol is described. Other reducible groups such as ketones and isolated double bonds remained intact. This methodology allows a short synthesis of (�)-b-conhydrine to be achieved

An efficient and stereoselective route to 1- deoxy- 5-hydroxy sphingosine analogues

A short and efficient synthesis of 1-deoxy-5-hydroxy sphingolipid is described. The key steps involved are a Jacobsen hydrolytic kinetic resolution (HKR) and Shibasaki 19s asymmetric Henry reactio

Experimental Evidence of Large Collective Enhancement of Nuclear Level Density and its Significance in Radiative Neutron Capture

The collective enhancement of nuclear level density and its fade out with excitation energy in deformed $^{171}$Yb nucleus has been inferred through an exclusive measurement of neutron spectra.The statistical model analysis of neutron spectra demonstrated a large collective enhancement factor of 40$\pm$3 for the first time, which corroborates with the recent microscopic model predictions but is an anomalous result compared with the measurements in the nearby deformed nuclei. The complete picture of the energy dependent collective enhancement has been obtained by combining with Oslo data below neutron binding energy. The significance of large collective enhancement in radiative neutron capture cross section of astrophysical interest is highlighted.Comment: 12 pages, 5 figure

Failure patterns of solder joints identified through lifetime vibration tests

A method for non-destructively tracking the integrity of flip chip solder joints through life is investigated in this paper. An industry standard double-sided PCB was designed and manufactured with 14 flip chips to assess the failure patterns of each flip chip and each solder joint in lifetime vibration tests. Two configurations of PCB finish were tested, Electro Nickel Immersion Gold (ENIG) and Hot Air Surface Levelled lead (Pb HASL) using automotive industry manufacturing processes and quality standards. A random vibration test over a frequency range 10 Hz to 1000 Hz was specified by automotive engineers to replicate vibrations typically found on road vehicles. This vibration profile was applied to test circuit board assemblies (CBA) for 4-minute intervals until failure of all chips. At each interval test boards were extensively scanned by an acoustic micro-imaging (AMI) microscope to non-destructively measure parameters of solder joints. This enabled tracking of mechanical joint connection through-life. Methods were developed to process the large number of acoustic images of each solder joint and form metrics to evaluate solder joint integrity. Results from AMI show that the solder joints exhibit three distinct zones as they age: crack initiation, crack propagation and then failure

Integrated Farming System: An ideal approach for developing more economically and environmentally sustainable farming systems for the Eastern Himalayan Region

The present work was carried out at Chandel Khullen village of Chandel hill district of Manipur during 2010-11 to 2012-13. The average holding size of the farmer was 1.33 ha in 2010-11, 1.96 ha in 2011-12 and 2.21 ha in 2012-13. The tribal farmer adopted seven components, i e crop production, vegetables, fruits, piggery, backyard poultry, fishery and water management as suggested by ICAR Manipur Centre. In 2010-11, the paddy yield was 3.5 tonnes/ha as compared to 4.79 tonnes/ha in 2012-13. It was mainly due to adoption of improved package and practices. The cabbage and onion yield increased by 103 and 54 per cent, respectively after adoption of improved cultivation methods under integrated farming system. Similarly, the papaya and banana production was increased by 275 and 270 per cent. There was marked increase in pork, chicken, egg and fish production. In 2012-13, this system also provided significantly higher Rs per Re invested than that of the other 2010-11. In Manipur, women’s participation is more in farming system rather than men. In the same way, this farming system also gives more opportunity to women to engage in agriculture farming. Thus integrated farming system provides new venture for employment and sustainable development of livelihood for North Eastern people. The overall result revealed that the improved practices with different crop and animal components are an excellent approach for sustainable production, income generation and employment opportunity for the small and marginal rural households of Manipur

Superior strength of tri-layered Al-Cu-Al nano-composites processed by high-pressure torsion

This investigation demonstrates that a solid-state reaction occurs by the application of high-pressure torsion (HPT) in the production of nanostructured multilayered hybrid Al-Cu systems. Three-layered stacks of Al/Cu/Al were subjected for up to 200 revolutions of HPT under an applied pressure of 6.0 GPa. Microstructural and mechanical properties analysis were carried out after HPT using X-ray diffraction, scanning and transmission electron microscopy, energy dispersive spectrometry (EDX), microhardness measurements and tensile tests. The SEM observations revealed the formation of a multi-nano-layered structure in the whole volume of the disks. Further investigations with the use of TEM demonstrated that each nano-layer consists of nano-grains having sizes of about 20 nm. Analysis by XRD and selected area electron diffraction (SAED) confirmed the formation of intermetallic CuAl2 and Cu9Al4 phases in the layered structures. The experiments also showed a significant improvement in microhardness (up to ~450 Hv) and tensile properties (over 900 MPa of UTS after 200 turns) when compared to both Al-1050 and 99.95%Cu alloys in the initial state and after HPT processing. The results demonstrate that HPT offers an outstanding opportunity for producing novel nanostructured Al-Cu multilayered composites having unique mechanical properties