On the Influence of Cross-Section Size on Measured Strength of SLM-Produced AlSi10Mg-Alloy

The freedom in choice of geometries in additive manufacturing (AM) favors the use of structures with large surface and small cross-section such as lattice structures and thin-walled hollow profiles. On the other hand, the practices of strength testing of metals require a certain bulk of the material to be printed to be able to produce a sample and test material properties. The size of the sample cross section might influence the strength and up to 30% decrease in strength for small struts was reported in the literature. Understanding the influence of the cross-section size on the strength of SLM-produced metal is crucial to be able to relate the strength determined through tensile testing and the strength of an SLM-produced component with complex geometry. This article deals with effect of cross-section size on the measured strength of the SLM-produced AlSi10Mg-alloy. It is demonstrated how the decrease in strength can be explained by the difference between measured and actual cross-section area induced by surface roughness rather than by the difference in microstructure between the samples of different sizes.publishedVersio

Role of Banks in Money Laundering through Fake Bank Accounts and Writing off Loan in Pakistan: An Analytical Study

Purpose: Recent media reports of money laundering through fake bank accounts implicate the involvement of banks in money laundering through "managed bank accounts". Further the waivers of loan of apparently sound institutions also give rise to specific questions and reservations on the role of banks. This paper attempts to explore the answer to those fundamental questions. Design/Methodology/Approach: The research follows qualitative content analysis methods to critically analyze the role of banks in money laundering and loan waiver policies. Findings: The research finds that despite of heavy banking regulations and laws the banking accounts are being used for money laundering. Further, the research concludes that the act of waiving off loans allegedly has provided a channel to misuse the public earned money, resulting in gross loss to the public exchequer. Implications/Originality/Value: The research concludes that the role of bank in maintaining the fake/idle accounts and the loan waiver policy and its malafide usage in the banking sector resulted in financial frauds and money laundering in Pakista

Moisture induced degradation in field-aged multicrystalline silicon photovoltaic modules

Moisture ingress is one of the key fault mechanisms responsible for photovoltaic (PV) devices degradation. Understanding moisture induced degradation (MID) mechanisms in field-aged PV modules is more reflective of the reality in the field. In the present work, MID products of reclaimed solar cells from 20-year-old field-aged silicon PV modules is investigated. The defective areas in the PV modules were identified using visual inspection, electroluminescence (EL), ultraviolet fluorescence (UV–F), and infrared thermal (IR-T) techniques. SEM-EDS analysis is used to elucidate the role of moisture on the observed degradation mechanisms. Degradation of the ethylene vinyl acetate (EVA) encapsulation produces acetic acid, carbon dioxide, phosphorus, sulfur, fluorine, and chlorine. Migration of metal ions under the influence of moisture ingress makes the formation of oxides, hydroxides, sulfides, phosphates, acetates, and carbonates of silver, lead, tin, copper, zinc, and aluminum feasible. Also, other competing reactions can lead to the formation of stannates of copper, silver, sodium, and zinc. Another observation is that, in the presence of MID species, Pb is preferentially corroded (to form lead acetate complexes) instead of the expected sacrificial Sn in the solder. These MID species account for different defects and fault modes that lead to parasitic resistance losses. This is witnessed by the 1.2%/year degradation in the Pmax of the PV module.publishedVersio

Defects and fault modes of field-aged photovoltaic modules in the Nordics

PV module durability and reliability influences its efficiency and return on investment. Hence, collection of ample and credible PV module reliability data in each climatic zone becomes increasingly essential. In this work, defects and fault modes of field-aged multicrystalline silicon PV modules installed outdoors in Grimstad from 2000 to 2011 are investigated. The investigations were done using visual inspection, current–voltage characterization, temperature coefficient profiling, ultraviolet fluorescence, electroluminescence, infrared thermal imaging, and SEM-EDS analysis. Most PV modules show signs of microcracks, moisture ingress, corrosion, potential induced degradation, optical degradation, and irregular temperature sensitivities. Oxidized silver, tin, and lead were observed in the SEM-EDS results, which confirmed the remnants of moisture ingress. On average, the modules show power output of 78% and their efficiency dropped from 13% to 10%. The average temperature coefficient of efficiency of the module was found to be ca. -0.5%/°C, corresponding to an average degradation rate of 1.09 %/year over the 20 years period. However, the annual degradation rates when the modules were in the field and indoors were 0.98% and 1.33 %, respectively. It is believed that limited evaporation of activated volatile carboxylic products under indoor conditions led to the formation and accumulation of carboxylic acids, hence higher rate of degradation. Moisture induced degradation (MID) mechanisms was the root cause for the overall degradation in the PV modules’ power output, especially over the later years.publishedVersio

Association of NS1 Antigen, IgM, IgG Antibodies and RT-PCR in the Diagnosis of Dengue Virus Infection

Background: To determine the association of ELISA based serological markersNS1 antigen, IgM, IgG antibodies and RT-PCR in the diagnosis of dengue virus infection Methods: In this descriptive cross sectional study 420 serum samples from patients with suspicion of dengue fever were tested for detection of dengue by NS1 antigen ELISA, IgG, IgM ELISA. RT-PCR for dengue was carried out in all NS1 antigen ELISA positive cases for confirmation of dengue. Results: Out of 420 cases , 249 cases were positive for either one of the three markers NS1, IgM,IgG. Males constituted 71.66%.Two hundred and two (48.09%) were positive for NS1 only,13 (3.09%) were positive for NS1 and IgG, 07 (1.66%) were NS1, IgM and IgG positive,16 (3.80%) were positive for IgG only ,11 (2.61%) were positive for NS1 and IgM whereas 171 (40.17%) samples were reported negative for NS1, IgM and IgG.RT-PCR was conducted on 233 NS1 positive cases out of which 80.06% cases turned out positive. Maximum number of cases belonged to DEN-2 genotype. Conclusion: Early diagnosis helps in improved patient care, suitable treatment, prevents severe complications and helps limit the spread of the disease. RT PCR is  a reliable test for the  diagnosis of acute dengue fever

The effect of Mo and Ge reactive elements on high-temperature oxidation of higher manganese silicide

Higher manganese silicide (HMS) alloys (Mnx-αMoαSiy-βGeβ (x = 0.99–1.011, α = 0.005–0.02, y = 1.75, β = 0.005–0.01)) were studied to elucidate the effect of Mo and Ge pertaining to oxidation. Oxidation experiments were conducted using thermogravimetry and characterized using x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Isoconversion experiments below 450 ◦C, shows that doping (up to 2 at%) raises the oxidation potential of HMS. Isothermally, the oxidation rate reduces buy one order of magnitude by doping on Mn and/or Si sites from 0.5 to 2 at%, revealing that the dopants-based oxides do not lessen the robustness of SiO2 oxide.publishedVersio

Immunoproliferative small intestinal disease (IPSID)

This study describes the frequency, demographics, clinical presentation, endoscopic findings, histopathological features, treatment and outcome of \u27Immunoproliferative small intestinal disease\u27 (IPSID). Archives contained a total of 27 cases of IPSID diagnosed and treated over an 18-year period. A M: F ratio of 2.4:1 was seen with a mean and median ages of 28.7 and 25 years. Most patients (68.8%) presented with abdominal pain and diarrhoea. In the majority (62.5%), duodenum was the primary site of involvement. Endoscopy showed polypoidal, raised or flat lesions. Biopsy findings included blunting or flattening of villi with dense plasma cell infiltrate and lymphoepithelial lesions. Twenty-four cases were categorized as stage A and B (benign and intermediate) and three were categorized as stage C (malignant, diffuse large B-cell lymphoma with plasmacytoid features). Stage A and B patients responded well to antibiotic treatment (tetracycline) with regression of the lesions while for stage C patients standard CHOP chemotherapy was administered

Preparation and Characterization of Spherical Nickel Silicide Powder by Inductively Coupled Plasma Spheroidization for Additive Manufacturing

Author's accepted manuscriptMetal alloy powder with spherical-shaped morphology, high flowability, and packing density is the main requirements for metal-based additive manufacturing (AM). Among metal alloys, nickel silicide is considered as a potential candidate due to its unique properties such as high melting point, good electrical conductivity, as well as high corrosion and wear resistance. However, the fabrication of spherical nickel silicide powder has proven to be a challenging task. In the present work, spherical NiSi16 alloy powders were synthesized by inductively coupled plasma spheroidization (ICPS). The influence of the feed rate on the properties of the as-prepared powder was investigated using different analytical techniques to evaluate the particle morphology, particle size distribution, oxygen content, bulk density, fluidity, and spheroidization rate. The results showed some unique advantages of the ICPS technology in the preparation of spherical nickel silicide powder that is believed to be well suited for AM.acceptedVersio