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Search Results: 1 - 10 of 887 matches for " bonding. "
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Fabrication of an Fluid Circuit for Equal Filling of a Well Array  [PDF]
Corinne S. Lengsfeld, Rachel S. Fulstone, Matt J. Opgenorth
Engineering (ENG) , 2012, DOI: 10.4236/eng.2012.410077
Abstract: Frequently in fluidic circuits there is a need to fill an array of wells. Methods for ensuring equal filling rates have hindered the application of microtechnology to cell culture applications directed to multiwell incubation. The greatest precision of equal fill volume to each well along a row occurred when the channels were extended into the third dimension, whereas, a traditional configuration is planar. This type of configuration utilizes vertical potential energy changes in cooperation with geometric restrictions. This paper presents the 3-D geometry that has five equally spaced wells to sustain equal filling. Moreover the fabrication process used to bond the multi-layer structure into a single 3-D circuit is presented.
Insilico studies of 2-methylheptyl isonicotinate produced by Streptomyces sps. 201 against dihydrodipicolinate synthase enzyme of Mycobacterium tuberculosis  [PDF]
Salam Pradeep Singh, Rajib Lochan Bezbaruah, Tarun Chandra Bora
Journal of Biophysical Chemistry (JBPC) , 2012, DOI: 10.4236/jbpc.2012.33027
Abstract: Tuberculosis is thought to have infected one-third of the world’s population and antibiotic resistance is a growing problem in multi-drug-resistant tuberculosis which is caused by Mycobacterium tuberculosis (MTB). It has been reported that Mycobacterial cell walls are characterized by high DAP (diaminopimelic acid) content—an intermediate of the (S)-lysine biosynthetic pathway. Hence, the Lysine/DAP biosynthetic pathway is a promising target because of its role in cell wall and amino acid biosynthesis. In this study we performed a molecular docking analysis of a novel antibacterial isolated from Streptomyces sps. 201 against dihydrodipicolinate synthase (DHDPS) enzyme of Mycobacterium tuberculosis. The docking studies suggest that the novel molecule binds at active site LYS 171 forming a cleft and at other potential ligand binding site exhibiting all the major interactions such as hydrogen bonding, hydrophobic interaction and electrostatic interaction with (THR55, TYR143, ARG148, LYS171, VAL257 and GLY256) residues.
Bond Strength of Brackets Bonded with Chemically and Light Activated Materials after Thermal Cycling  [PDF]
Rafael Menezes-Silva, Leonardo Amaral dos Reis, Bhenya Otonni Tostes, Dhelfeson Willyan Douglas de Oliveira, Maria Helena Santos
Advances in Materials Physics and Chemistry (AMPC) , 2015, DOI: 10.4236/ampc.2015.59035
Abstract: The aim of this study was to evaluate the bond strength of orthodontic brackets bonded to tooth enamel with different polymer composites after simulated clinical aging, and analyze the enamel/ bond system fracture interface. 80 human premolars, were randomly divided into five groups (n = 16). G1: CO (Concise Ortodontica—3M ESPE), G2: SB (SuperBond—Ortho Source), G3: FMO (Fill Magic OrtodonticoVigodent), G4: TXT (Transbond XT—3M ESPE) and G5: TP (Transbond Plus Self Etching Primer + Transbond Plus Color Change—3M ESPE). In all groups, the metal orthodontic bracket was bonded to the tooth enamel surface. The specimens were submitted to 3000 thermal cycling baths for 30 s, at temperatures of 5°C, 37°C and 55°C (±1°C). Afterwards they were subjected to shear testing and the results were analyzed by the Student’s-t test (p < 0.05). G1 presented the highest bond strength value, followed by G4 > G5 > G2 > G3. In all groups the majority of the fractures at the interface of the specimens were cohesive, except in G3, which presented the largest number of adhesive fractures. After clinical aging, the chemically activated material (CO) showed higher bond strength than the light activated types (FMO, TXT and TP). The self-etching adhesive system (TP) showed similar bond strength to that of conventional systems (FMO and TXT).
Using Microgripper in Development of Automatic Adhesive Glue Transferring and Binding Microassembly System  [PDF]
R. J. CHANG, C. C. CHEN
Engineering (ENG) , 2010, DOI: 10.4236/eng.2010.21001
Abstract: A system using microgripper for gluing and adhesive bonding in automatic microassembly was designed, implemented, and tested. The development of system is guided by axiomatic design principle. With a compliant PU microgripper, regional-edge-statistics (RES) algorithm, and PD controller, a visual-servoing system was implemented for gripping micro object, gluing adhesive, and operating adhesive bonding. The RES algorithm estimated and tracked a gripper’s centroid to implement a visual-servoing control in the microassembly operation. The main specifications of the system are: gripping range of 60~80μm, working space of 7mm×5.74mm×15mm, system bandwidth of 15Hz. In the performance test, a copper rod with diameter 60μm was automatically gripped and transported for transferring glue and bonding. The 60μm copper rod was dipped into a glue container and moved, pressed and bonding to a copper rod of 380μm. The amount of binding glue was estimated about 5.7nl.
Influence of Benzoate on Substituent Benzoic Acids with Implications on Spectroscopic Studies through Inter Molecular Hydrogen Bonding  [PDF]
Ravi Shankar Kumar
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.26068
Abstract: Comprehensive study on the homologous series of compounds in the form A-R- HHB are synthesized with central rigid core as benzoic acids together with substituent’s alkoxy (A) and alkyl (R) group of equal chain lengths from 5 to 10 are connected to hexyl-p-hydroxy benzoate (HHB). These complexes form supramolecular structures by self assembling process due to intermolecular hydrogen bonding. The formation is analyzed with techniques involving polarizing optical microscope, infrared spectroscopy, proton NMR spectroscopy and powdered X-ray diffraction. Results suggest that complexes arise from both A and R groups exhibit enantiotropic layered texture of crystal G phase observed by microscopic studies due to flexible nature of mesogenics. The conversion of free to molecular complexes is determined with variations in spectral shifts between its terminal groups COOH and OH of molecules involving inter molecular hydrogen bonding and its bonding index by FTIR spectra. The changes in structure and dynamics due to hydrogen bonding in complexes are convinced by proton NMR spectra with chemical shifts in specified range. The defects in crystal structure responsible for enantiotropic phenomena are analyzed by powdered X ray diffraction.
Hydrogen Incorporation in Undoped ZnO Nanoparticles  [PDF]
Suhendro Purbo Prakoso
World Journal of Condensed Matter Physics (WJCMP) , 2011, DOI: 10.4236/wjcmp.2011.14019
Abstract: Zinc Oxide nanoparticles in the size range of ~18 - 23 nm are prepared using wet chemical method. Hydrogen concentration in the samples was obtained by drying the precipitate at various temperatures. XRD pattern showed a single phase wurzite structure for ZnO nanoparticles. Average crystallite sizes and lattice parameters determined from XRD pattern showed a gradual increase with increasing dry temperature, while the lattice strain showed the opposite direction. Optical studies revealed the optical gap ranging from 3.05 - 3.24 eV. Hydrogen incorporation in the specimen was studied using infrared absorption measurement. Infrared absorption measurements revealed six hydrogen-related local vibrational modes in the wave number range from 2800 to 3600 cm–1. To remove hydrogen, some samples were annealed up to 800°C. Infrared absorption measurements showed that the local vibational modes disappeared. This shows that the observed local vibrational modes are due to the presence of hydrogen. The results of XRD and optical studies will be correlated with the results obtained from infrared absorption measurements.
Influence of Small Amphiphiles on Aqueous Dispersions of β-Lactoglobulin A and Bovine Serum Albumin: (1) Intermolecular Interactions  [PDF]
Zahur Z. Haque, Guichard L. Bohoua
Food and Nutrition Sciences (FNS) , 2015, DOI: 10.4236/fns.2015.612117
Abstract: Hydrophilic and hydrophobic (φ) interactions among amphiphiles play critical roles in interfacial properties of proteins and other smaller amphiphiles and affect the creation and stability of foams and emulsions in food systems. Contribution of small amphiphiles on H-bonding and hydrophobic (φ) interactions at a model interface comprising of a water-hydrophobized surface interface as reflected by contact angle (θ) of fatty acid free bovine serum albumin (FAF-BSA), bovine serum albumin (BSA), and β-lactoglobulin variant A (β-LGA) was investigated. Amphiphiles were used with either protein in neutral water or α-bromonaphtalene (α-BrN) (22°C) to obtain θ-H2O and θ-α-BrN measurements, respectively. θ-α-BrN reflected influence of φ-interactions on θ since α-BrN molecules do not partake significantly in H-bonding. Ionic nature of the amphiphiles had no significant effect. Dramatic difference was between zwitterionic Z8 and Z12. At 1%, Z8 significantly increased H-bonding in BSA and β-LGA by 26% and 55%, respectively, whereas Z12, which is more hydrophobic, decreased it by 50% and 21%. At the same concentration, φ-interactions were enhanced by Z8 for BSA by 37% and by all amphiphiles except Z12 for FAF-BSA.
The Inter Relationship of Mental State between Antepartum and Postpartum Assessed by Depression and Bonding Scales in Mothers  [PDF]
Kafumi Sugishita, Kiyoko Kamibeppu, Hiroya Matsuo
Health (Health) , 2016, DOI: 10.4236/health.2016.812126
Abstract: The number of deaths caused by child abuse is increasing, which is one of social concerns. The mental health of mothers might be related to child abuse. The aim of this study was to examine and compare the mental state of mothers in both the antepartum and postpartum period assessed by the Edinburgh Postnatal Depression Scale (EPDS) and Mother-Infant-Bonding-Scale (MIBS), and compare the results. Participants (n = 134) were recruited twice in antepartum medical checkups (20 to 36 weeks of gestation) and postpartum medical checkups (1 month after birth). Information on characteristics of participants was collected from medical records in both periods. Family function and ante-postpartum mental health were assessed by Family APGAR, EPDS, and MIBS. Antepartum depressive state was related to postpartum depressive state (p = 0.015), antepartum bonding was related to bonding in postpartum bonding (p = 0.0001), and antepartum bonding disorder was related to postpartum depressive state (relative risk = 11.7). Worries about costs and poor of family function were related to the mental health of mothers in both the antepartum and postpartum periods. Antepartum depressive state is an indicator of postpartum depression. We suggested that health professionals conduct an evaluation of mother’s mental health and related factors in the antepartum period. The present findings emphasize the importance of antepartum mental health as a predictor of postpartum depression and bonding disorder.
Quantum Chemical Characterization of Hydrogen Bonding Sites in Three 4-(4-Halo-Phenyl)-6-(Furan-2-yl) Pyrimidin-2-Amine Derivatives  [PDF]
Yafigui Traore, Kafoumba Bamba, Nahossé Ziao, Sopi Thomas Affi, Mamadou Guy-Richard Kone
Computational Chemistry (CC) , 2017, DOI: 10.4236/cc.2017.53008
Abstract: Hydrogen bonding (HB) sites in three pyrimidine compounds derivatives (DP), namely 4-(4-fluorophenyl)-6-(furan-2-yl) pyrimidin-2-amine (DP-1), 4-(4-chlorophenyl)-6-(furan-2-yl) pyrimidin-2-amine (DP-2) and 4-(4-bromophenyl)-6-(furan-2-yl) pyrimidin-2-amine (DP-3), have been investigated by quantum chemistry methods, especially at HF/6-311+G(d,p) and B3PW91/6-311+G(d,p) levels. Hydrogenfluori deserved as probe for hydrogen bonding complexes. Molecular electrostatic potential maps, geometricparameters of HB complexes, as well as energetic parameters of the complexation reactions have been computed. Finally, one out of two nitrogen atoms of pyrimidine nucleus has been identified as the major hydrogen bonding site in the three pyrimidine derivatives, with respective percentages of around 83.0% and 93.2% at HF/6-311+G(d,p) and B3PW91/6-311+G(d,p) levels.
Compressive Behavior of Steel Members Reinforced by Patch Plate with Welding and Bonding  [PDF]
Xiaoyang Liu, Mikihito Hirohata
Open Journal of Civil Engineering (OJCE) , 2018, DOI: 10.4236/ojce.2018.84026
Abstract: Repair and reinformcement of aged civil steel structures is one of the important issues for maintaining and using them for a long term. For repair and reinforcement of deteriorated civil steel structures due to fatigue and corrosion, patch plate reinforcement is widely applied. Bolting is generally used because of easy quality control and many construction achievements. However, bolting has downsides including holes made and weight increase. Welding is considered to overcome these demerits but in reality the application of welding is unsatisfactory due to the possibility of fatigue crack occurring from the welded part. In this study, a patch plate strengthening system of welded joint assisted with bonding has been proposed. The compressive behaviors of weld-bond jointed specimen were investigated by a series of experiments and FE analysis. It was confirmed that use of welding and bonding was effective to enhance compressive strength of specimen, due to better load-carrying capacity of patch plate compared with sole use of welding.
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