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Analysis of Crack Formation in Germanium Substrate at AlInGaP Die Bonding Process
Luruthudass Annaniah,
Mutharasu Devarajan
Issue:
Volume 4, Issue 1, January 2015
Pages:
1-7
Received:
24 November 2014
Accepted:
9 December 2014
Published:
18 December 2014
Abstract: Cracked die is a serious failure mode in Light Emitting Diode (LED) industry – affecting the LED quality and long-term reliability performance. In this paper, an investigation has been carried out to find out a relation between die bonding force and the occurrence of die crack at Germanium (Ge) substrate due to die attach (DA) ejector pin indentation. Based on the analysis, the results show that cracks start to occur at 60 gram-force (gF) bond force and above. The crack length at the die substrate increases with respect to the bond force. These indented dies were further analyzed by using Scanning Electron Microscope (SEM). The results show plastic deformation, slip traces and material pile-up at the vicinity of ejector pin crater. Some samples were sectioned using Focus Ion Beam (FIB) and it was found the crack depth does not exceed beyond 20.5μm and it follows the (111) plane. These findings, concludes that cracks start to appear at 60gF and they are confined to surface level even indented at extreme load (140gF). These cracks are far away from the active region of LED.
Abstract: Cracked die is a serious failure mode in Light Emitting Diode (LED) industry – affecting the LED quality and long-term reliability performance. In this paper, an investigation has been carried out to find out a relation between die bonding force and the occurrence of die crack at Germanium (Ge) substrate due to die attach (DA) ejector pin indentati...
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Structure, Electrical Resistivity, Oxidation and Corrosion Behavior of Tin-Lead Eutectic Alloy
E. Gouda,
I. Faquhi,
S. Kariri,
M. Qohal,
Y. Kariri
Issue:
Volume 4, Issue 1, January 2015
Pages:
8-11
Received:
28 November 2014
Accepted:
22 December 2014
Published:
20 January 2015
Abstract: The structure, electrical resistivity, oxidation and corrosion behaviors of the eutectic Sn-Pb alloy have been studied and analyzed using X-ray, Ohm’s law circuit, thermal gravimetric analysis (TGA) and chemical weight loss method, respectively. The results showed that, the alloy exhibited two phase mixtures of α-Pb and β-Sn. The I-V characteristic curve of this alloy was described and the room temperature electrical resistivity was calculated and found to be 24.6 ± 1 µΩ.cm. Also, the variation of electrical resistivity with temperature was described in the range from the room temperature to 91 ºC and the temperature coefficient of resistivity (TCR) was also calculated. Furthermore, it was found that, the alloy exhibited a good oxidation and corrosion resistance for long run.
Abstract: The structure, electrical resistivity, oxidation and corrosion behaviors of the eutectic Sn-Pb alloy have been studied and analyzed using X-ray, Ohm’s law circuit, thermal gravimetric analysis (TGA) and chemical weight loss method, respectively. The results showed that, the alloy exhibited two phase mixtures of α-Pb and β-Sn. The I-V characteristic...
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Effect of the Near-Net Shape Forming on Silicon Morphology in an Al–Si Functionally Graded Material Generated by the Centrifugal Method
Yasuyoshi Fukui,
Daisaku Nara,
Kazuyo Fushimi,
Mitsuhiro Nakao,
Noriyoshi Kumazawa
Issue:
Volume 4, Issue 1, January 2015
Pages:
12-19
Received:
23 December 2014
Accepted:
8 January 2015
Published:
20 January 2015
Abstract: A work toward practical usage of hypereutectic Al–25 mass% Si alloy, which exhibits superior properties, as a functionally graded material (FGM) was done. The Al–Si FGM, which is based on the concept of overcoming the limitations imposed by the presence of a hard silicon phase in an aluminum matrix, was generated by a vacuum centrifugal method as a thick-walled tube. Grain coarsening, which is the primary disadvantage of the centrifugal method, was observed. The fraction of silicon phase in the tube unexpectedly varied from greater than 60 mass% at the outer surface to 15 mass% at the inner surface because of the greater density of molten silicon compared to that of the eutectic melt. Thus, the outer region of the tube was lighter than the inner region after solidification. FGM billets for near-net shape forming were machined from the thick-walled tube and were formed into an Al–Si FGM cup using a backward extruding. The products of the FGM cup were successfully manufactured in the temperature range from 853 K (580 ºC) to 863 K (590 ºC) through visco-plastic deformation. The fraction of silicon phase in the FGM cup varied from greater than 70 mass% Si at the formed cup bottom region to less than 15 mass% Si at the cup wall region. Coarse silicon particles were refined irrespective of the pre-existence of elongated spindle-shaped particles under some experimental conditions. The optimum operating conditions were inferred to be high-speed operation at approximately 853 K (580 °C), which was just above the melting point of the eutectic Al–Si alloy.
Abstract: A work toward practical usage of hypereutectic Al–25 mass% Si alloy, which exhibits superior properties, as a functionally graded material (FGM) was done. The Al–Si FGM, which is based on the concept of overcoming the limitations imposed by the presence of a hard silicon phase in an aluminum matrix, was generated by a vacuum centrifugal method as a...
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Synthesis and Characterization of the Peroxo Complexes of Uranium (VI) Containing Organic Acids and Amine Bases Ligands
Issue:
Volume 4, Issue 1, January 2015
Pages:
20-25
Received:
25 December 2014
Accepted:
11 January 2015
Published:
22 January 2015
Abstract: Several new peroxo complexes of U(VI) have been synthesized and characterized by element analyses and various physico-chemical techniques. A number of organic and amine ligands were used to form the complexes having compositions, [UO(O2)amH2L], where, [amH=amino acids, such as glycine, phenylalanine, leucine ; L= ligands such as pyridine, 2-picoline, 4-picoline, quinoline, iso-quinoline. The analytical data are in good agreement with the proposed empirical formulae of the U(VI) complexes. The molar conductance values indicate all the complexes of U(VI) are non-electrolyte in DMF revealing that the anions are covalently bonded in all the cases. The disappearance of the v(O-H) mode observed in the free amino acid molecule clearly indicate the loss of protons from O-H group coordination, revealing that acids are dinegative bidentate ligand coordinating through the carboxylate anion. The characteristic v1(O-O) mode of the complexes appeared in the region 842-916 cm-1, indicating that the dioxygen moieties are bonded on “side–on” fashion with the U(VI). The magnetic moment values indicated that these complexes were diamagnetic in nature suggesting no changes in the oxidation states of the metal ions upon complexation. These data also consistent with eight fold coordination of U(VI). The electronic spectral data of the complexes showed bands in between 315-380 nm due to the charge transfer band only.
Abstract: Several new peroxo complexes of U(VI) have been synthesized and characterized by element analyses and various physico-chemical techniques. A number of organic and amine ligands were used to form the complexes having compositions, [UO(O2)amH2L], where, [amH=amino acids, such as glycine, phenylalanine, leucine ; L= ligands such as pyridine, 2-picolin...
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Comparative Studies on the Metallurgical and Biological Activity of Peroxo Complexes of Molybdenum (VI) and Uranium (VI)
Issue:
Volume 4, Issue 1, January 2015
Pages:
26-30
Received:
25 December 2014
Accepted:
4 January 2015
Published:
22 January 2015
Abstract: New peroxo complexes of molybdenum (VI) and uranium (IV) have been prepared. The complexes were characterized on the basis of elemental analyses, conductivity measurements, magnetic measurements, infrared spectral studies and by reactions with allyl alcohol, triphenylphosphine and triphenylarsine. The complexes of U (VI) showed strong activity against both the gram positive and gram negative bacteria than the other complexes indicating the higher zone of inhibition. The present findings of MIC experiment showed that the complex 3 of U (VI) was more potent against all the bacteria tested than the other complex. Results showed that the complex 2 of Mo (VI) exhibits more toxic to brine shrimp compared to other complexes of Mo (VI) and U (VI) indicating the lower values of LC50 and LC99 for both the exposure 16h and 36h.
Abstract: New peroxo complexes of molybdenum (VI) and uranium (IV) have been prepared. The complexes were characterized on the basis of elemental analyses, conductivity measurements, magnetic measurements, infrared spectral studies and by reactions with allyl alcohol, triphenylphosphine and triphenylarsine. The complexes of U (VI) showed strong activity agai...
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Effect of Light Intensity on the I-V Characteristics of LaF3/Porous-Silicon Structure Prepared by Chemical Bath Deposition Technique
Md. Hafijur Rahman,
Abu Bakar Md. Ismail
Issue:
Volume 4, Issue 1, January 2015
Pages:
31-34
Received:
14 November 2014
Accepted:
27 November 2014
Published:
26 January 2015
Abstract: Effect of Light intensity on the I-V characteristics of LaF3/PS heterojunction has been investigated in this report. LaF3 layers have been deposited by a novel chemical bath deposition (CBD) technique. With this simple technique LaF3 produced as LaCl3 are made to react with hydrofluoric (HF) acid on the porous silicon substrate. This enables direct deposition of LaF3 on the pore walls of the porous silicon leading to a successful passivation of PS. The compositions of the deposited LaF3 were confirmed by Energy Dispersive of X-ray (EDX) analysis. The current increases with light intensity. From the experimental results it can be concluded that lanthanum fluorides can be deposited on the PS surface by the CBD technique, which provides the required passivation for PS. This passivation can enable the PS to be considered as an important material for photonics.
Abstract: Effect of Light intensity on the I-V characteristics of LaF3/PS heterojunction has been investigated in this report. LaF3 layers have been deposited by a novel chemical bath deposition (CBD) technique. With this simple technique LaF3 produced as LaCl3 are made to react with hydrofluoric (HF) acid on the porous silicon substrate. This enables direct...
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AgInSe2 Thin Films Prepared by Electrodeposition Process
Mounir Ait Aouaj,
Raquel Diaz,
Fouzia Cherkaoui El Moursli,
Arturo Tiburcio-Silver,
Mohammed Abd-Lefdil
Issue:
Volume 4, Issue 1, January 2015
Pages:
35-38
Received:
29 November 2014
Accepted:
14 December 2014
Published:
26 January 2015
Abstract: In this work, the one step electrodeposition process was used to prepare Ag-In-Se thin films. The films were deposited at room temperature from a bath containing 1-3x10-3 M AgNO3, 6x10-2 M InCl3 and 3x10-2 M of H2SeO3. The KSCN at a concentration of 0.681 M was used as complexing agent. The pH value of the solution was 1.4. Applied potentials to SCE were chosen between -0.3 V and -1.1 V. Films were deposited onto molybdenum/glass and ITO/glass substrates. We showed that the films’ compositions are strongly function of the growth conditions. Heat treatment at 320 °C during 30 minutes under nitrogen led to AgInSe2 chalcopyrite p-type semiconductor. Also, the morphology and crystallinity of the films is improved by annealing. AgInSe2 films deposited on indium tin oxide showed a band gap value of about 1.24 eV.
Abstract: In this work, the one step electrodeposition process was used to prepare Ag-In-Se thin films. The films were deposited at room temperature from a bath containing 1-3x10-3 M AgNO3, 6x10-2 M InCl3 and 3x10-2 M of H2SeO3. The KSCN at a concentration of 0.681 M was used as complexing agent. The pH value of the solution was 1.4. Applied potentials to SC...
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Evaluation of Addition ABS and EPDM Effect on the Mechanical Properties of Ternary Polymer Blends
Sihama Issa Salih,
Jawad Kadhum Oleiwi,
Rawaa Adnan Abdle Ameer
Issue:
Volume 4, Issue 1, January 2015
Pages:
39-46
Received:
30 December 2014
Accepted:
14 January 2015
Published:
28 January 2015
Abstract: Polymer blends are capable of providing materials with extended useful properties beyond the range that can be obtained from single polymer. Blends of polystyrene (PS) and polypropylene (PP) with adding acrylonitrile-butadiene-styrene (ABS) or ethylene propylene diene monomer (EPDM) are prepared in different ratios by melt blending technique which was carried out using a double screw extruder. The tensile, flexural, impact and hardness tests of all the prepared samples were study. The results from this work show that the elongation property and impact properties for blend system increase with increase PP content in polymer blend of (PS:PP), also increase value of these properties with increase the ratio of adding (ABS or EPDM) for polymer blend (PS:5%PP).The highest values of impact strength was (10.68Kj/m2) for ternary polymers blend (90%PS:5%PP:5%EPDM) and the high values of fracture toughness (6.125MPa√m ) for ternaty polymer blend (90%PS:5%PP:5%ABS).
Abstract: Polymer blends are capable of providing materials with extended useful properties beyond the range that can be obtained from single polymer. Blends of polystyrene (PS) and polypropylene (PP) with adding acrylonitrile-butadiene-styrene (ABS) or ethylene propylene diene monomer (EPDM) are prepared in different ratios by melt blending technique which ...
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A Comparison of Shear Bond Strength of Orthodontic Brackets Bonded with Four Flowable Composites Bonded under Contamination: An Ex-Vivo Study
Sunil Kumar M.,
Mahantesh C.,
Umesh H. M.,
Ashita Talwar,
Sufia Qaiser,
Sonal Sahasrabudhe
Issue:
Volume 4, Issue 1, January 2015
Pages:
47-51
Received:
19 December 2014
Accepted:
4 January 2015
Published:
10 February 2015
Abstract: Objective: To evaluate the shear bond strength of the brackets bonded with adhesive and flowable composites under contamination by human blood and human saliva& to evaluate enamel damage post debonding using ARI index. Material and Methods: 100 human premolars extracted for orthodontic reasons were used & shear bond strengths of 4 flowable composites and one conventional composite were evaluated under 2 bonding conditions: (1) contamination with saliva (2) contamination with blood. Contamination was done after the application of primer in all the groups and before bonding the brackets, decontamination was done by using the air water spray for 5 seconds and air drying the surface. Shear bond strengths were measured with universal testing machine after placing the bonded specimen in deionized water and incubator at 37˚C for 72 hours to permit adequate water absorption and equilibration. After debonding, each specimen was examined under a stereoscopic zoom microscope (10X) to identify the location of the bond failure. The residual composite remaining on the premolar was assessed by using the remnant index (ARI), where each specimen was scored according to the amount of material remaining on the enamel surface. Results: conventional composite showed the highest bond strength in both blood and salivary contaminations. Among the flowable composites, each behaved differently. Blood contamination showed reduced bond strengths in all the groups. Decontamination with air water spray and air drying the surface before bonding the brackets seems to be satisfactory. Conclusion: with use of a primer, flowable composites can be used to bond the orthodontic brackets under contamination and decontamination with air water spray for 5 seconds and air drying the surface before bonding seems to be satisfactory if contamination occurs after the application of the primer.
Abstract: Objective: To evaluate the shear bond strength of the brackets bonded with adhesive and flowable composites under contamination by human blood and human saliva& to evaluate enamel damage post debonding using ARI index. Material and Methods: 100 human premolars extracted for orthodontic reasons were used & shear bond strengths of 4 flowable composit...
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A Systematic Study on Electronic and Thermodynamical Properties of Some LiM (M= Ag, Hg and Tl) Intermetallics
Neetu Paliwal,
Vipul Srivastava
Issue:
Volume 4, Issue 1, January 2015
Pages:
52-58
Received:
12 January 2015
Accepted:
29 January 2015
Published:
10 February 2015
Abstract: Binary intermetallic system, Li-M (M=Ag, Hg and Tl) has been systematically evaluated and optimized using self consistent tight binding linear muffin tin orbital (TB-LMTO) method under ambient conditions. The lattice constant, bulk modulus and its pressure derivative were calculated. The lattice constants were calculated to be 3.05, 3.20 and 3.34 Å and bulk modulii were predicted to be 61.8, 50 and 37.8 GPa, for LiAg, LiHg and LiTl, respectively. Electronic band structures, partial and total densities of states were derived in B2 (CsCl) phase for the first time. The band structures show metallic character and conductivity was mostly governed by Li-d and M-d states. Furthermore, Debye temperature, Grüneisen constant and molar heat capacity in terms of coefficients of the electronic and lattice heat capacities were estimated.
Abstract: Binary intermetallic system, Li-M (M=Ag, Hg and Tl) has been systematically evaluated and optimized using self consistent tight binding linear muffin tin orbital (TB-LMTO) method under ambient conditions. The lattice constant, bulk modulus and its pressure derivative were calculated. The lattice constants were calculated to be 3.05, 3.20 and 3.34 Å...
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Hardening and Characterisation of 0.45%C Steel Using Clay/Water Media as Quenchant
Oghenevweta Erhuvwu Joseph,
Asuke Ferdinand
Issue:
Volume 4, Issue 1, January 2015
Pages:
59-64
Received:
6 January 2015
Accepted:
20 January 2015
Published:
11 February 2015
Abstract: Hardening and characterization of 0.45%C steels using clay/water media as quenchants were investigated. Different weight percent of clay was added to water to form clay/water quenching media and water was equally use as the control. The steel specimens were heated to the austenizing temperature and quenched in these liquid media. The specific latent heat of vapourization of the liquid media, hardness value, impact energy, yield strength and tensile strength of the specimen were analyzed. The morphologies of the as-quenched steels were observed by using SEM. The results revealed that addition of 2-4wt% clay to water gives the best mechanical properties. This may probably be due to a uniform release of thermal energy in form of latent heat of vapourization across the dimension of the specimen and prevention of the oxide film formation on the surface of the workpiece. However, further addition of clay greater than 4% result to decrease in the mechanical properties of the specimen tested. The specific latent heat of vapourization decreases as the weight fraction of clay in water increases. Results from the microstructural examination indicate predominantly formation of martensite and retained austenite phases.
Abstract: Hardening and characterization of 0.45%C steels using clay/water media as quenchants were investigated. Different weight percent of clay was added to water to form clay/water quenching media and water was equally use as the control. The steel specimens were heated to the austenizing temperature and quenched in these liquid media. The specific laten...
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