Nd:YAG laser welding of stainless steel 304 for photonics device packaging

Although pulsed Nd:YAG laser welding has been widely used in microelectronics and photonics packaging industry, a full understanding of various phenomena involved is still a matter of trials and speculations. In this research, an ultra compact pulsed Nd:YAG laser with wavelength of 1.064 µm has been used to produce a spot weld on stainless steel 304. The principal objective of this research is to examine the effects of laser welding parameters such as laser beam peak powers, pulse durations, incident angles, focus point positions and number of shots on the weld dimensions: penetration depth and bead width. The ratio of the penetration depth to the bead width is considered as one of the most critical parameters to determine the weld quality. It is found that the penetration depth and bead width increase when the laser beam peak power, pulse duration and number of shot increase. In contrast, the penetration depth decreases when the laser beam defocus position and incident angle increase. This is due to the reduction of the laser beam intensity causing by the widening of the laser spot size. These experimental results provide a reference on an optimal laser welding operations for a reliable photonics device packaging. The results obtained shows that stainless steel 304 is suitable to be used as a base material for photonics device packaging employing Nd:YAG laser welding technique

Wave function-dependent mobility and suppression of interface roughness scattering in a strained SiGe p-channel field-effect structure

The 4 K Hall mobility has been measured in a top-gated, inverted, modulation-doped Si/Si0.8Ge0.2 structure having a Si:B doping layer beneath the alloy. From comparisons with theoretical calculations, we argue that, unlike an ordinary enhancement-mode SiGe p-channel metal–oxide–semiconductor structure, this configuration leads to a decrease of interface roughness scattering with increasing sheet carrier density. We also speculate on the nature of the interface charge observed in these structures at low temperature

Phenotypes of Alpha 1 Antitrypsin in Karachi, Pakistan

Objective: To determine serum level of the protease inhibitor, to identify phenotypes and determine their frequencies. Study Design: A prospective study. Setting: PMRC Research Centre, JPMC and the Aga Khan University Hospital Karachi. Subjects: Healthy aduIts without history ol peptic ulcer disease and a normal endoscopy. Methodology: Quantitive measurement of serum alpha 1 AT was carried out by radial immunodiffusion. phenotyping by iso-electric focusing and confirmation of phenotypes by immunofixation and DNA analysis technique. Results:Serum alpha I AT was low in 13.4% of the subjects. Ni MM phenotype predominated followed by SZ SS, MZ and ZZ. DNA diagnosis accurately resolved the phenotypes as S and Z. Conclusion: Frequency by phenotype associated with total and intermediate deficiency is less in the populatio

REPRODUCTIVE BIOLOGY OF THE RED BIGEYE (Priacanthus macracanthus Cuvier, 1829) IN PALABUHANRATU BAY, INDONESIA

The reference point of reproductive biology play an important roles in developing a baseline information for fishery management. Different waters will provide different overview of fisheries related to its biological aspects. The red bigeye (Priacanthus macracanthus) is one of economically important demersal fish species in Indonesia. To support the biological status of this species, a regular field observation were carried out during May 2016 to April 2017 in Palabuhanratu bay, south of West Java. The objective of this study is to estimate the spawning season and potential reproductive stages including to evaluate how the key management related to the species and its gear selectivity. Numbers of red bigeye (Priacanthus macracanthus) specimen was collected from bottom gillnetter and hand liner. Basic information related to length-weigth, bio-reproduction (maturity) were collected regularly to determine GSI, Fecundity and its impact of fishing (Lc, Lm) to evaluate the recent stock status. The result showed sex ratio no significant differences between males and females except in September to December. The growth pattern indicated negative allometric. The predicted of spawning seasons were around June-July and December-January. Mean of fecundity was estimated to be 230,000 ± 178,000 eggs. Management keys were obtained i.e. length at first maturity (Lm) value was to be 21.9 cm TL which is smaller than length at first capture (Lc) 22.4 cm TL for bottom gill netter and 23.1 cm TL for average fishes caught by hand liner. Therefore it is recommended to close the waters in the bay area during the spawning period. In the case of catch, it is important to apply the precautionary approach with emphasizes to the size of fish allowed to be captured more than the Lm value (above 21.9 cm TL).

Flammability action of tires material after adding flame inhibitor

Magnesium hydroxide was used as flame inhibitor to increased flame resistance for tires .Magnesium hydroxide was adding with (5%,10%) weight percents to rubber master batch of tire and then exposed the resulting material to a flame generated from gas torch with (10 mm) exposure distance . Method of measuring the surface temperature opposite to the flame was used to determine the heat transferred through tire material. The results were obtained shows enhanced flame resistance for tire by added magnesium hydroxide and this resistance increased by increasing hydroxide Percentage

Machine Learning-Based Peripheral Artery Disease Identification Using Laboratory-Based Gait Data

Peripheral artery disease (PAD) manifests from atherosclerosis, which limits blood flow to the legs and causes changes in muscle structure and function, and in gait performance. PAD is underdiagnosed, which delays treatment and worsens clinical outcomes. To overcome this challenge, the purpose of this study is to develop machine learning (ML) models that distinguish individuals with and without PAD. This is the first step to using ML to identify those with PAD risk early. We built ML models based on previously acquired overground walking biomechanics data from patients with PAD and healthy controls. Gait signatures were characterized using ankle, knee, and hip joint angles, torques, and powers, as well as ground reaction forces (GRF). ML was able to classify those with and without PAD using Neural Networks or Random Forest algorithms with 89% accuracy (0.64 Matthew’s Correlation Coefficient) using all laboratory-based gait variables. Moreover, models using only GRF variables provided up to 87% accuracy (0.64 Matthew’s Correlation Coefficient). These results indicate that ML models can classify those with and without PAD using gait signatures with acceptable performance. Results also show that an ML gait signature model that uses GRF features delivers the most informative data for PAD classification

Molecular docking studies on InhA, MabA and PanK enzymes from Mycobacterium tuberculosis of ellagic acid derivatives from Ludwigia adscendens and Trewia nudiflora

There is an urgent need to discover and develop new drugs to combat Mycobacterium tuberculosis, the causative agent of tuberculosis (TB) in humans. In recent years, there has been a renewed interest in the discovery of new anti-TB agents from natural sources. In the present investigation, molecular docking studies were carried out on two ellagic acid derivatives, namely pteleoellagic acid (1) isolated from Ludwigia adscendens, and 3,3′-di-O-methyl ellagic acid 4-O-α-rhamnopyranoside (2) isolated from Trewia nudiflora, to investigate their binding to two enzymes involved in M. tuberculosis cell wall biogenesis, namely 2-trans-enoyl-ACP reductase (InhA) and β-ketoacyl-ACP reductase (MabA), and to pantothenate kinase (PanK type I) involved in the biosynthesis of coenzyme A, essential for the growth of M. tuberculosis. Molecular docking experiments were performed using AutoDock Vina. The crystal structures of InhA, MabA and PanK were retrieved from the RCSB Protein Data Bank (PDB). Isonicotinic-acyl-NADH for InhA and MabA, and triazole inhibitory compound for PanK, were used as references. Pteleoellagic acid showed a high docking score, estimated binding free energy of −9.4 kcal/mol, for the MabA enzyme comparable to the reference compound isonicotinic-acyl-NADH.Knowledge on the molecular interactions of ellagic acid derivatives with essential M. tuberculosis targets could prove a useful tool for the design and development of future anti-TB drugs

Measuring the Cost Efficiency of Banks Operating in the MENA Region

This paper tried to model the efficiency of banks operating in the MENA region between 2005 and 2011, using the stochastic frontier technique. The sample under study included banks from 11 different MENA countries. The empirical results show that – on average – those banks could save up to 19% of their consumed resources while producing the same level of outputs. We also find a wide difference in efficiency among the MENA banking sectors, with scores ranging between 55% (for Egypt) and 97% (for UAE). Finally, by detecting the impact of several internal and external factors on the efficiency scores, we find that economic growth, inflations rates, corruption, exchange rates, trade openness, size of the government, bank capital, and bank profitability, all have a significant impact on bank efficiency

Experimental study of debris-induced scour around a slotted bridge pier

One of the most common problems for river engineers is the accumulation of waterborne debris upstream of the bridge piers. In addition to reducing the cross-sectional flow area, debris increases the drag force exerted to the pier and contributes to scour. Several studies have been carried out by previous researchers to examine the usefulness of different types of countermeasures. The effectiveness of these countermeasures is not well understood when debris accumulation occurs. In this study, the effect of debris accumulation on the efficiency of a bridge pier slot, as scour countermeasure, is investigated experimentally. A total of 54 experiments were carried out under different hydraulic and debris geometrical conditions. The results showed that slots were effective in protecting bridge piers against scouring in presence of debris. Depending on the debris shape, the reduction efficiency may increase or decrease for a slotted pier in presence of debris accumulation when compared to the standard pier conditions without debris accumulation. Except for the inverse pyramid shape, the maximum scour is generally more reduced due to sheltering effect when the debris is located on the bed. While debris accumulation can lead to a reduction of the slot efficiency, the slot can be considered a reliable countermeasure against scouring. The outcome of this study can help the design of new bridges affected by large wood debris accumulation