bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis, Characterization and Unusual Dielectric Behaviour of λ-Shaped Mesogenic Homologous Series With Polar Substituents
Authors: Chand P. B. , Manohar R.
Published: October 2017

A new λ-shaped mesogenic homologous series with polar bromo and nitro substituent was synthesized by fixing rigid 2-bromo-4-nitrophenylazo groups to a resorcinol moiety. 4-n-alkoxybenzoyl groups esterify both the phenolic -OH groups. In the present series, methoxy and ethoxy derivatives are non-mesogenic, n-propyloxy to n-octyloxy derivatives exhibit enantiotropic nematic mesophase. Smectic C (SmC) mesophase commences from the n- octyloxy derivative as an enantiotropic phase and is retained up to the last member synthesized. The effect of polar bromo and nitro substituent on mesomorphic properties is discussed. In this paper, we also report the unusual dielectric behaviour of n-octyloxy and n-tetradecyloxy derivatives of the present λ-shaped mesogenic homologous series. The dielectric permittivity of the sample was found to be unusually low in SmC phase in comparison to nematic phase. We have explained it on the basis of two-conformer model, which can exist in SmC phase due to specific shape of the molecule. The model has been supported by calculating activation energy of both the possible conformers from Arrhenius plot of relaxation frequency versus temperature. There is a clear difference in the value of activation energy of both the conformers as expected.Keywords: C. Differential scanning calorimetry (DSC); D. Dielectric properties; D. Phase transitionsThe Himalayan Physics  Vol.2, No.2, May, 2011Page: 16-25Uploaded Date: 31 July, 2011
Etching of Crystalline Silicon in Thermal Environment
Authors: Lamichhane Shobha Kanta , Lamsal Min Raj
Published: October 2017

Thin wafer have become a basic need for a wide variety of new microelectronic products. Wafers that have been thinned using wet etch process on the backside have less stress compared with standard mechanical back grinding. Isotropic wet etching of silicon is typically done with a mixture of nitric and hydrofluoric acids. As the silicon is etched and incorporated in the etching solution the etch rate will decrease with time. This variation has been modeled. The focus of this paper is to compare the process control technique for maintaining a consistent etch rate as a function of time and wafer processed.Keywords: Isotropic and anisotropic etching; MEMS; SOI; LPCVDThe Himalayan Physics Vol.2, No.2, May, 2011Page: 38-42Uploaded Date: 1 August, 2011
An Experimental Study on Electrical Behaviour of (Pb1-xSnx) TiO3(x=0.10,0.20,0.30) Ceramics
Authors: Subedi Mitra Mani
Published: October 2017

(Pb1-xSnx)TiO3(x=0.10,0.20,0.30)(PST) powders are synthesized using the conventional dry route in a mixture of PbCO3,SnCl2.2H2O and TiO2.The samples are sintered at 1050°C to achieve about 95% of theoretical density. It is observed that PST sample reveals dielectric anomaly around 190°C for x=0.10,180°C for x=0.20 and no anomaly is observed for x=0.30 which confirms the ferroelectric behaviour of PST 10%,PST 20% and PST 30% as paraelectric. The peak value of the real part of dielectric constant is higher during cooling mode than that for heating mode as per simple Landau theory argument, which gives the thermal hysteresis of 10°C for PST 10%, 5°C for 20%.This observation confirms the first order nature of the ferroelectric to paraelectric transition and tending towards second order. The feature of PST has great applications such as capacitors, temperature sensors as well as humidity and gas sensors. So, it is recommended to extend further study.The Himalayan Physics Vol.2, No.2, May, 2011Page: 54-56Uploaded Date: 1 August, 2011
Photonic Computer: A Next Generation of Computer World
Authors: Bhattarai Lakshmi Nath
Published: October 2017

Software in the computer is used to study from sub-atomic particles to lagre scale strucute like galaxies. Computer technology found to make computer small and as fast as possible. As photon travel tansfer than electric curren, time required for computation in photonic computer will be highly reduced and portable.Keywords: Sub-atomic particles; Photon travel tansferThe Himalayan Physics Vol.2, No.2, May, 2011Page: 65-66Uploaded Date: 1 August, 2011
Nanoscale Measurement of Surface Roughness and the existing Surface Forces of Aluminum by AFM
Authors: Pun Purna B , Lamichhane Shobha K
Published: October 2017

The surface contamination affects Atomic Force Microscope (AFM) performance. Thermal agitation during mapping doping, thermal oxidation, annealing impurities and crystal defects promotes the roughness; various kinds of forces on the surface can be detected by the interaction between tip of cantilever and sample. This interaction not only help us to understand the characteristics and morphology of the sample but also useful to measure the surface force of the aluminum sample too.Key words: Atomic Force Microscope (AFM) performance; Thermal oxidation; Annealing impurities; Crystal defectsThe Himalayan Physics Vol.2, No.2, May, 2011Page: 76-79Uploaded Date: 1 August, 2011
Neutrinos
Authors: Regmi Jeevan
Published: October 2017

Neutrinos are one of the fundamental particles that make the universe. They are produced by the decay of radioactive elements and are elementary particles that lack the electric charge. The name neutrino was coined by Enrico Fermi as a word play on neutrone, the Italian name of the neutron. Of all high-energy particles, only weakly interacting neutrinos can directly convey astronomical information from the edge of the universe and from deep inside the most cataclysmic high energy process.The Himalayan PhysicsVol. 3, No. 3, July 2012Page : 64-68
Graphene: A Peculiar Allotrope Of Carbon
Authors: Bhattarai Laxmi Nath
Published: October 2017

Graphene is a two dimensional one atom thick allotrope of Carbon. Electrons in grapheme behave as massless relativistic particles. It is a 2 dimensional nanomaterial with many peculiar properties. In grapheme both integral and fractional quantum Hall effects are observed. Many practical application are seen from use of Graphene material.The Himalayan PhysicsVol. 3, No. 3, July 2012Page: 87-88
Effect And Application of Ionization Radiation (X-Ray) In Living organism
Authors: Adhikari Suraj Raj
Published: October 2017

X-ray is electromagnetic radiation of extremely short wavelength and high frequency. X-rays show wave as well as particle-like properties. X-ray is used in wide range of application such as industry, medicine and science application. It is essential tool in modern medicine. It can result in both beneficial and dangerous biological effects. These ionizing radiations penetrate the living tissues and can destroy living cells, chromosomal aberrations and carcinogenic effect.The Himalayan PhysicsVol. 3, No. 3, July 2012Page: 89-92
Impact of Size Distribution of Nanoparticles in TiO2 Paste for its Application in Dye Sensitized Solar Cells
Authors: Dhungel Suresh Kumar , Park Chang Woo
Published: October 2017

Titanium dioxide (TiO2) nanoparticles have been recognized as a significant candidate for Dye SensitizedSolar Cell (DSSC) applications. A comparative study of the TiO2 films with two different patterns of the nanoparticlessize distribution is reported in this article. Crystallinity of the nanoparticles, distribution of size of nanoparticles and theperformance parameters of the DSSCs fabricated out of the films were thoroughly analyzed for the films of both types of TiO2.The TiO2 film with its nanoparticles distributed over a wider range showed better interconnection between the nanoparticlesand hence less porosity that resulted in lower area available for the adsorption of dye after sintering whereas the TiO2 filmwith its nanoparticles distributed over a narrower range showed relatively poor interconnection between the nanoparticlesleading to enhanced porosity suitable for DSSC application. A proper balance between porosity of the TiO2 film and theinterconnection between the nanoparticles can ensure the DSSC with improved performance parameters.The Himalayan Physics Vol. 4, No. 4, 2013 Page: 27-31 Uploaded date: 12/23/2013
Unified Field Theory
Authors: Poudel Parashu Ram
Published: October 2017

Unified field theory is the long-sought means of tying together all known phenomena to explain the nature and behaviour of all matter and energy in existence. The quest for unification has been the perennial theme of modern physics. The belief that all physical phenomena can be reduced to simple and explained by a smaller number of laws is the central tenet of physics. Such a theory could potentially unlock all the secrets of nature and make a myriad of wonders possible, including such benefits as time travel and an inexhaustible source of clean energy, among many others. This paper aims to explain unified theory and its development towards the unification of four interactions in brief.The Himalayan Physics Vol. 4, No. 4, 2013 Page:87-90 Uploaded date: 12/23/2013
A Study of r- and u-Magnitude Dependence in the Spatial Orientation of Spin Vectors of SDSS Galaxies having redshift 0.10 < z < 0.11
Authors: Yadav Shiv Narayan , Aryal Binil
Published: October 2017

We present a study of spin vector orientations of 44749 r and u-magnitude SDSS (Sloan Digital Sky Survey) galaxies having redshift 0.10 to 0.11. The r and u-magnitudes are observed through 616.5 nm and 354.3 nm CCD (charge coupled device) filter attached to SDSS telescope located at New Mexico, USA. We have converted two dimensional data to three dimensional galaxy rotation axes. Our aim is to find out non-random effects in the spatial orientation of galaxies. In addition, we wanted to check r and u-magnitude dependence in the spatial orientation. The expected isotropy distribution curves are obtained by removing the selection effects and performing a random simulation method. In general, spin vector orientations of galaxies is found to be random, supporting Hierarchy model of galaxy formation. A local anisotropy is observed in few samples suggesting a gravitational tidal interaction between neighbor galaxies, a merging process in which the angular momentum vector distort the original alignment of evolution of rotational supported system to the randomized system.The Himalayan Physics Year 5, Vol. 5, Kartik 2071 (Nov 2014)Page: 1-11
Preliminary Study on the State of Pre-Monsoon Time Climatic Comfort Over the Chitwan Valley, Nepal
Authors: Regmi Ram Prasad
Published: October 2017

Available with full text.The Himalayan Physics Vol. 5, No. 5, Nov. 2014Page: 59-68
“Remote sensing”- A part of an Applied Physics
Authors: Shah Arbind Kumar
Published: October 2017

Physics is the most fundamental of all the sciences & scientific developments or technologies. Physics is also behind the modern technologies such as internet & mobile, whereas applied physics does the role of their application to modern technologies. Applied physics describes the laws & phenomenon of nature with their application in different fields like: Physics of imaging, Atmospheric Physics, Nanotechnology, Remote Sensing etc. The Remote Sensing (R. S.) technology is discussed in detail through this paper. The Himalayan Physics Vol. 5, No. 5, Nov. 2014 Page: 102-108
Multiverse
Authors: Baral Sanjaya , Chhetri Dhurba
Published: October 2017

Multiverse scenarios in cosmology assume that other universes exist "beyond" our own universe. They are an exciting challenge both for empirical and theoretical research as well as for philosophy of science. They could be necessary to understand why the big bang occurred, why (some of) the laws of nature and the values of certain physical constants are the way they are, and why there is an arrow of time. This essay clarifies competing notions of "universe" and "multiverse"; it proposes a classification of different multiverse types according to various aspects how the universes are or are not separated from each other; it reviews the main reasons for assuming the existence of other universes: empirical evidence, theoretical explanation, and philosophical arguments. The Himalayan Physics Vol. 5, No. 5, Nov. 2014 Page: 109-111
Rootfinding : An Iterative Tool to Solve Different Problems
Authors: Adhikari Iswarmani
Published: October 2017

The aim of this paper is to apply the iteration methods for the solution of non-linear equations. Among the various root finding techniques, two of the common iterative methods Regula-falsi (false position) and the Secant method are used in two different problems to show the applications of numerical analysis in different fields.

The Himalayan Physics

Vol. 5, No. 5, Nov. 2014

Page: 121-125
Study of Structural and Electronic Properties of Fluoride Perovskite KCaF3 using FP-LAPW Method
Authors: Neupane K. , Thapa R. K.
Published: October 2017

To study the structural and electronic properties of cubical perovskite KCaF3, the first principles calculation within the full potential linearized augmented plane wave (FP-LAPW) method is applied. The exchange correlation effects are included through the GGA exchange potential. The calculated structural properties such as equilibrium lattice constant, the bulk modulus and its pressure derivative are in agreement with the published results of other authors. From our study we have found that the band gap of KCaF3 is 6.4 eV which is the indication of insulating behavior.The Himalayan Physics Vol. 6 & 7, April 2017 (100-103)
Retrospective Review of Student Research Projects in a Canadian Master of Science in Physical Therapy Programme and the Perceived Impact on Advisors' Research Capacity, Education, Clinical Practice, Knowledge Translation, and Health Policy
Authors: Lacey Courtney , Scodras Stephanie , Ardron Julie , Sellan Ryan , Garbaczewska Martyna , O'Brien Kelly K. , Salbach Nancy M.
Published: October 2017

Purpose: This study's aim was to characterize the nature of students' research conducted for a Master of Science in Physical Therapy (MScPT) degree programme at a Canadian university and evaluate the lead advisors' perspectives of its impact on their research capacity, education, clinical practice, knowledge translation, and health policy. Methods: We conducted a quantitative, cross-sectional, retrospective review of research reports from 2003 to 2014 to characterize the MScPT students' research and a quantitative, cross-sectional e-survey of lead research advisors to evaluate the impact of this research. Results: Data were abstracted from reports of 201 research projects completed between 2003 and 2014. Projects were conducted primarily in university-affiliated hospitals (41.6%) or the university's physical therapy department (41.1%), and the majority (52.5%) had a clinical focus. Of the 95 lead advisors of 201 projects, 59 advisors (response rate 62.1%) of 119 projects completed the survey questionnaire. The respondents most frequently identified clinical practice (45.1%) and advisors' research capacity (31.4%) as areas positively affected by the students' research. Conclusions: The MScPT students' research projects facilitate the conduct of extensive research internally and across affiliated hospitals. This research appears to advance not only clinical practice but also the ability of lead advisors to undertake research.
Facile Synthesis of 1-(4-Bromophenyl)-1H-Tetrazol-5-Amine and Related Amide Derivatives
Authors: Yang Hao , Ouyang Yifan , Sun Yutong , Wang Zhe , Zhu Xuanli , Tan Xiaoli , Wang Hao , Hong Wei
Published: October 2017

An efficient one-pot synthesis of 1-(4-bromophenyl)-1 H-tetrazol-5-amine was performed using 4-bromoaniline as the starting material. A novel and widely applicable amidation procedure was then employed, whereby 1-(4-bromophenyl)-1 H-tetrazol-5-amine was acylated with different acyl chlorides in the presence of lithium bis(trimethylsilyl)amide as catalyst, for the high-yield synthesis of [1-(4-bromophenyl)-1 H-tetrazol-5-yl]amide derivatives.
Synthesis, Structure, Photoluminescent and Semiconductor Properties of, and Theoretical Calculations for, a Novel Zinc Complex
Authors: Yi Xiu-Guang , Chen Wen-Tong , Huang Jian-Gen , Zhang Ding-Wa , Wang Yin-Feng
Published: October 2017

A novel zinc complex [Zn3(2,2′-bi-1H-imidazole)2(1H-biimidazole)2(SO4)2] n has been synthesised through a solvothermal reaction and structurally characterised by single-crystal X-ray diffraction. It has a one-dimensional chain-like structure with both tetrahedral and square pyramidal zinc atoms. A three-dimensional supramolecular framework is constructed through hydrogen-bonding interactions. Photoluminescence shows that the complex displays an emission in the blue region of the light spectrum that time-dependent density functional theory calculations reveal can be attributed to ligand-to-ligand charge transfer. Solid-state diffuse reflectance measurements show the existence of a narrow optical band gap of 2.08 eV.
Management of Postmenopausal Women with Simple Cyst
Authors: Nasreen Sk Zinnat Ara
Published: October 2017

Objective(s): Aim of the study was to explore the outcome of conservative treatment for the postmenopausal women having small cysts.Materials Methods: This prospective cross sectional study was carried out in ZH Sikder Women Medical College & Hospital, Medinova and Popular hospital between January 2011 to June 2016. Five hundred (500) postmenopausal women with simple cysts were enrolled after counseling and taking written consent. Inclusion criteria were- cysts size should not be more than 5cm, they should be unilocular, without having any solid component or any debries. Exclusion criteria were, she or her family should not have any cancer of ovary, breast, or colon. Also women with HRT were excluded from the study. Thorough history taking, clinical examination, and some investigation like CA125, and TVS with colour Doppler was carried out for all women. CT Scan. MRI, and PET Scan were reserved for cases where colour Doppler ultrasonogram was suspicious. All the patients were followed up every 3 months for 3 to 5 years. Surgery was done if the patient developed any symptoms, or if there was any increment of sizes of cysts or there was any sonographic changes were evident. MRI1 (malignancy risk index) was calculated for each patient. Data were analyzed by SPSS where all calculation rate of less than 0.05 was considered significant.Results: Among 500 cysts, 285 cysts resolved spontaneously, which is highly significant (p <0.05), 165 cysts needed surgery and 50 cysts regressed very slowly and did not regress completely. Histopathology of surgical specimen revealed all were benign except 4 cysts, which became malignant or malignant potential.Conclusion: Postmenopausal women with simple cysts not more than 5cm,which are unilocular, unilateral, without having any solid component and with normal Doppler study are rarely malignant. So if MRI 1 is below 200 we may avoid unnecessary surgery and assure the postmenopausal women for the conservative treatment with regular follow up.Bangladesh J Obstet Gynaecol, 2016; Vol. 31(1) : 3-9
Psychosocial Effects of Infertility among the Childless couples at a Specialized Fertility Centre in Dhaka, Bangladesh
Authors: Vashkar Shaikh Mahmud Kamal , Ehsan Nazia , Haseen Fariha
Published: October 2017

Objective(s): To identify the common psychosocial effects of infertility among the childless couples of Bangladesh.Materials and Methods: This cross sectional quantitative survey was conducted at a tertiary level fertility center in Dhaka, Bangladesh from November 14, 2012 to November 30, 2012. Respondents were chosen by judgment sampling. Only the couples without any child were chosen for interview. Sixty-six couples were interviewed and three couples refused who came for treatment at the center. Primary data was collected from the respondents with preformed questionnaire. Informed written consent was taken before the interview, from both partners or only one partner where the other was absentResults: The mean ages of the men were 36 years and women were 28 years. The mean age for age at marriage of men and women were 29 and 22 respectively. Among the psychological effects, stress and anxiety were common in both men and women. Family problems were found less among the respondents. Only significant one that was found in both men and women was the pressure from family members, which was found in about one third of the respondents. Social effects were not found among half of the respondents. The other half avoided family gatherings (16%), meeting friends (13%), social gatherings (10%) and 15% respondents said that they do not like to go out at all.Conclusion: The psychosocial effects of infertile couples can lead to depression, frustration and sometimes aggression making them dysfunctional social beings. It also decreases work productivity and quality of life. Necessary preventive measures should be taken through appropriate public health interventions like patient counseling, awareness campaign etc. to avoid the psychosocial consequences.Bangladesh J Obstet Gynaecol, 2016; Vol. 31(1) : 28-33
Case Report on Sertoli Cell Tumor of Ovary
Authors: Begum Kohinoor , Khanom Kamil Ara , Saha Joysree
Published: October 2017

A 33 years old lady presented with history of irregular menstrual cycle followed by menorrhagia. USG revealed left ovarian solid mass but all tumor markers were within normal range. A solid mass on left sided ovary was found on laparotomy. Histopathological examination of the mass showed well differentiated sertoli cell tumor. Tumors of the stroma (Leydig cells) and/or sex cords (Sertoli cells) represent approximately 8% of ovarian tumors and develop from the connective tissue (respectively, interstitial and nurse cells) of the ovary. Because these cells participate in ovarian hormonal function, most of the sex-cord or stromal tumors are able to secrete hormones (estrogens, androgens, corticoids), which explains the hormonal dysfunctions associated with these tumors. Their prognosis are difficult to establish; some of the tumors are almost always benign (Sertoli cell tumors, Leydig cell tumors), whereas others are malignant but with more-or-less delayed local-regional or metastatic relapses.Bangladesh J Obstet Gynaecol, 2016; Vol. 31(1) : 54-56
Association of Serum C-reactive Protein in Preeclampsia and its Effect on Fetal Birth Weight  A Case Control Study
Authors: Sharmin Shahanaj , Chy Shahanara , Alam Diadrul , Banu Nasreen , Rashid Fahmida , Kabir Shanjida
Published: October 2017

Objective(s): The aim of this study was to evaluate the association of serum C-reactive protein (CRP) in preeclampsia (PE) and its effect on fetal birth weight.Materials and methods: This case control study was conducted in Chittagong Medical College Hospital, Bangladesh, from July 2013 to June 2014. Study population was pregnant women of third trimester with preeclampsia (case group) and normal blood pressure (control group). The maternal serum C-reactive protein (CRP) levels were measured by immune turbidometric assay between 32 weeks to term. The women were divided into three groups: mild PE, severe PE (according to ACOG criteria) and normal healthy group. The value of CRP and its correlation with birth weight was compared between groups.Results: One hundred and fifty (150) pregnant women were analyzed. Among them 50 were case and 100 control. There was no difference between age of the patients of both groups. The mean systolic blood pressure was 148.40 ± 12.35 mm Hg in case and 122.15 ± 6.44 mmHg in control group. The mean diastolic blood pressure was 100.00 ± 9.74 mmHg in case and 74.05 ± 5.97 mmHg for the control. The systolic and diastolic blood pressure was significantly higher in preeclamptic group (P < 0.000). C-reactive protein was 10.28 ± 7.25 mg/ mL in mild PE and 10.94 ± 6.32 mg/mL in severe PE and 3.45 ± 1.71 mg/mL in normotensive group, which was significantly higher in case than control group (P = 0.000). Preeclamptic women delivered at a significantly shorter gestational age than normal pregnant women. Mean gestational age during delivery for the case group and control group was 39.02 ± 1.6 and 39.58 ± 0.8 weeks respectively. Mean birth weight in PE (2.52 ± 0.42 kg) was significantly lower than normal pregnancies (2.88 ± 0.29 kg). The sensitivity and specificity of CRP were 68% and 98% respectively. Multiple regression analysis showed that there is a strong association between CRP levels and PE and birth weight.Conclusion: This small study showed that in case group CRP was raised in 68% cases which is much higher in comparison to healthy control group where CRP was high only in 2% cases. High CRP has association with low birth weight. Therefore, CRP may be used as cost effective investigation to identify the risk of preeclampsia and its effect on fetal birth weight.Bangladesh J Obstet Gynaecol, 2016; Vol. 31(2) : 75-80
Outcome of Abdominal Sacrocolpopexy for Post Hysterectomy Vaginal Vault Prolapse
Authors: Chowdhury Liza , Khanam Nurun Nahar , Janna Junnu Rayen
Published: October 2017

Objective (s): The aim of this study was to explore the outcome of abdominal sacrocolpopexy for the correction of post hysterectomy vaginal vault prolapse.Materials and Methods: This prospective study was done over the period of five years from 2011 to 2015 where twenty patients of vault prolapse were subjected to abdominal sacrocolpopexy. Procedure was completed by securing the vaginal apex to the anterior longitudinal ligament of sacrum using synthetic mesh. Intra and postoperative complications and patients satisfaction was assessed.Results: No post-operative serious complications were reported during follow up period. The vaginal vault was well supported in all patients with no recurrent vault prolapse. One patient had mild asymptomatic rectocele. No mesh complication was found during the follow up period.Conclusion: The abdominal sacrocolpopexy achieves excellent correction of post hysterectomy vaginal vault prolapse with minimal morbidity.Bangladesh J Obstet Gynaecol, 2016; Vol. 31(2) : 90-93
From Point Clouds to Building Information Models: 3D Semi-Automatic Reconstruction of Indoors of Existing Buildings
Authors: Macher Hélène , Landes Tania , Grussenmeyer Pierre
Published: October 2017

The creation of as-built Building Information Models requires the acquisition of the as-is state of existing buildings. Laser scanners are widely used to achieve this goal since they permit to collect information about object geometry in form of point clouds and provide a large amount of accurate data in a very fast way and with a high level of details. Unfortunately, the scan-to-BIM (Building Information Model) process remains currently largely a manual process which is time consuming and error-prone. In this paper, a semi-automatic approach is presented for the 3D reconstruction of indoors of existing buildings from point clouds. Several segmentations are performed so that point clouds corresponding to grounds, ceilings and walls are extracted. Based on these point clouds, walls and slabs of buildings are reconstructed and described in the IFC format in order to be integrated into BIM software. The assessment of the approach is proposed thanks to two datasets. The evaluation items are the degree of automation, the transferability of the approach and the geometric quality of results of the 3D reconstruction. Additionally, quality indexes are introduced to inspect the results in order to be able to detect potential errors of reconstruction.
Enhanced Emission by Accumulated Charges at Organic/Metal Interfaces Generated during the Reverse Bias of Organic Light Emitting Diodes
Authors: Nozoe Soichiro , Matsuda Masaki
Published: October 2017

A high frequency rectangular alternating voltage was applied to organic light emitting diodes (OLEDs) with the structure ITO/TPD/Alq3/Al and ITO/CoPc/Alq3/Al, where ITO is indium-tin-oxide, TPD is 4,4′-bis[N-phenyl-N-(m-tolyl)amino]biphenyl, CoPc is cobalt phthalocyanine, and Alq3 is Tris(8-quinolinolato)aluminum, and the effect on emission of the reverse bias was examined. The results reveal that the emission intensity under an alternating reverse-forward bias is greater than that under an alternating zero-forward bias. The difference in the emission intensity (∆I) increased both for decreasing frequency and increasing voltage level of the reverse bias. In particular, the change in emission intensity was proportional to the voltage level of the reverse bias given the same frequency. To understand ΔI, this paper proposes a model in which an OLED works as a capacitor under reverse bias, where positive and negative charges accumulate on the metal/organic interfaces. In this model, the emission enhancement that occurs during the alternating reverse-forward bias is rationalized as a result of the charge accumulation at the organic/metal interfaces during the reverse bias, which possibly modulates the vacuum level shifts at the organic/metal interfaces to reduce both the hole injection barrier at the organic/ITO interface and the electron injection barrier at the organic/Al interface under forward bias.
Workflow for Criticality Assessment Applied in Biopharmaceutical Process Validation Stage 1
Authors: Zahel Thomas , Marschall Lukas , Abad Sandra , Vasilieva Elena , Maurer Daniel , Mueller Eric , Murphy Patrick , Natschläger Thomas , Brocard Cécile , Reinisch Daniela , Sagmeister Patrick , Herwig Christoph
Published: October 2017

Identification of critical process parameters that impact product quality is a central task during regulatory requested process validation. Commonly, this is done via design of experiments and identification of parameters significantly impacting product quality (rejection of the null hypothesis that the effect equals 0). However, parameters which show a large uncertainty and might result in an undesirable product quality limit critical to the product, may be missed. This might occur during the evaluation of experiments since residual/un-modelled variance in the experiments is larger than expected a priori. Estimation of such a risk is the task of the presented novel retrospective power analysis permutation test. This is evaluated using a data set for two unit operations established during characterization of a biopharmaceutical process in industry. The results show that, for one unit operation, the observed variance in the experiments is much larger than expected a priori, resulting in low power levels for all non-significant parameters. Moreover, we present a workflow of how to mitigate the risk associated with overlooked parameter effects. This enables a statistically sound identification of critical process parameters. The developed workflow will substantially support industry in delivering constant product quality, reduce process variance and increase patient safety.
Brosimum Alicastrum as a Novel Starch Source for Bioethanol Production
Authors: Olguin-Maciel Edgar , Larqué-Saavedra Alfonso , Pérez-Brito Daisy , Barahona-Pérez Luis , Alzate-Gaviria Liliana , Toledano-Thompson Tanit , Lappe-Oliveras Patricia , Huchin-Poot Emy , Tapia-Tussell Raúl
Published: October 2017

Ramon (Brosimum alicastrum) is a forest tree native to the Mesoamerican region and the Caribbean. The flour obtained from Ramon seeds is 75% carbohydrate, of which 63% is starch, indicating its potential as a novel raw material for bioethanol production. The objective of this study was to produce ethanol from Ramon flour using a 90 °C thermic treatment for 30 min and a native yeast strain (Candida tropicalis) for the fermentation process. In addition, the structure of the flour and the effects of pretreatment were observed via scanning electron microscopy. The native yeast strain was superior to the commercial strain, fermenting 98.8% of the reducing sugar (RS) at 48 h and generating 31% more ethanol than commercial yeast. One ton of flour yielded 213 L of ethanol. These results suggest that Ramon flour is an excellent candidate for ethanol production. This is the first report on bioethanol production using the starch from Ramon seed flour and a native yeast strain isolated from this feedstock. This alternative material for bioethanol production minimizes the competition between food and energy production, a priority for Mexico that has led to significant changes in public policies to enhance the development of renewable energies.
Energy Consumption Forecasting for University Sector Buildings
Authors: Amber Khuram Pervez , Aslam Muhammad Waqar , Mahmood Anzar , Kousar Anila , Younis Muhammad Yamin , Akbar Bilal , Chaudhary Ghulam Qadar , Hussain Syed Kashif
Published: October 2017

Reliable energy forecasting helps managers to prepare future budgets for their buildings. Therefore, a simple, easier, less time consuming and reliable forecasting model which could be used for different types of buildings is desired. In this paper, we have presented a forecasting model based on five years of real data sets for one dependent variable (the daily electricity consumption) and six explanatory variables (ambient temperature, solar radiation, relative humidity, wind speed, weekday index and building type). A single mathematical equation for forecasting daily electricity usage of university buildings has been developed using the Multiple Regression (MR) technique. Data of two such buildings, located at the Southwark Campus of London South Bank University in London, have been used for this study. The predicted test results of MR model are examined and judged against real electricity consumption data of both buildings for year 2011. The results demonstrate that out of six explanatory variables, three variables; surrounding temperature, weekday index and building type have significant influence on buildings energy consumption. The results of this model are associated with a Normalized Root Mean Square Error (NRMSE) of 12% for the administrative building and 13% for the academic building. Finally, some limitations of this study have also been discussed.
The Nature and Articulation of Ethical Codes on Tailings Management in South Africa
Authors: Poswa Tobius , Davies Theophilus
Published: October 2017

It is well recognized that the mining industry in South Africa is highly rated for its substantial contribution to the country’s economic growth, including employment and infrastructural development. It is also known that mining and ore processing activities potentially pose a severe threat to public health and environmental well-being, in the way operations are carried out, mine wastes are disposed of (in dumps), local communities are relocated, mine management and the mining community, in general, perceive established environmental standards and etiquette. This paper examines ethical practices and norms in the South African mining industry, with particular reference to the management of tailings dams. We analyse the modes of articulation of the country’s regulatory instruments for tailings management, and review the corporate social responsibility (CSR) approach of leading mining companies. Despite decades of research and resulting recommendations on tailings management, it is concluded that the current legislations are largely ineffective, that the level of adherence by mine management and the mining community is low, and that the mechanisms for compliance monitoring is weak. New perspectives on legislative issues for unsolved problems in tailings handling are put forward, and directions for future research, indicated.
The Immunogenicity of Branded and Biosimilar Infliximab in Rheumatoid Arthritis According to Th9-Related Responses
Authors: Talotta Rossella , Berzi Angela , Doria Andrea , Batticciotto Alberto , Ditto Maria , Atzeni Fabiola , Sarzi-Puttini Piercarlo , Trabattoni Daria
Published: October 2017

Our objective was to evaluate the immunogenicity of branded and biosimilar infliximab by detecting changes in T-helper-9 (Th9) percentages induced by an in vitro stimulation test. Methods: Peripheral blood mononuclear cells collected from 55 consecutive rheumatoid arthritis (RA) outpatients (15 drug free, 20 successfully treated with branded infliximab, 20 branded infliximab inadequate responders) and 10 healthy controls were cultured, with or without 50 μg/mL of infliximab originator (Remicade®) or 50 μg/mL of infliximab biosimilar (Remsima®) for 18 h. Th9 lymphocytes were identified by means of flow cytometry as PU.1 and IRF4-expressing, IL-9-secreting CD4+ T cells. Furthermore, the markers CCR7 and CD45RA were used to distinguish naïve from memory IL-9 producer cells. Results: Under unstimulated conditions, the drug-free RA patients had the highest percentages of Th9 lymphocytes. Following stimulation with branded infliximab, the percentages of PU.1 and IRF4-expressing Th9 cells, CCR7+, CD45RA− (central memory) and CCR7−, CD45RA− (effector memory) cells significantly increased in the group of inadequate responders, but no significant variation was observed after exposure to the biosimilar of infliximab. Conclusions: Th9 cells seem to be involved in the immune response to the epitopes of branded, but not biosimilar, infliximab, and this may depend on the recall and stimulation of both central and effector memory cells.
Association between Stress and the HPA Axis in the Atopic Dermatitis
Authors: Lin Tzu-Kai , Zhong Lily , Santiago Juan
Published: October 2017

The hypothalamic–pituitary–adrenal (HPA) axis is one of the body’s neuroendocrine networks that responds to psychological stress (PS). In the skin, there exists a peripheral HPA axis similar to the central axis. Glucocorticoids (GCs) are key effector molecules of the HPA axis and are essential for cutaneous homeostasis. Atopic dermatitis (AD) is a condition typically characterized by a chronic relapsing course that often results in PS. HPA dysfunction is present in AD patients by the decreased response of GCs elevation to stress as compared to those unaffected by AD. Nevertheless, in skin, acute PS activates several metabolic responses that are of immediate benefit to the host. During the acute phase of PS, increased endogenous GCs have been shown to provide benefit rather than by aggravating cutaneous inflammatory dermatoses. However, a chronic T helper cell type 2 (Th2) predominant cytokine profile acts as a negative feedback loop to blunt the HPA axis response in AD. In this article, we reviewed the role of CRF, pro-opiomelanocortin (POMC)-derived peptides, GCs of the HPA, and 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) in AD, with a discussion of the pathogenetic mechanisms of inflammation and skin barrier functions, including antimicrobial defense, and their association with PS.
Optimizing the Parameters of TIG-MIG/MAG Hybrid Welding on the Geometry of Bead Welding Using the Taguchi Method
Authors: Schneider Cristian , Lisboa Camila , Silva Rodrigo , Lermen Richard
Published: October 2017

The main aim of this work was to evaluate the influence and optimize the factors of the TIG-MIG/MAG hybrid welding process on the geometry of the weld bead. An experimental design using the Taguchi methodology (robust design method) was used to conduct the experiments. The experiments were carried out according to an orthogonal matrix with 27 experiments, with three replicates each, totaling 81 test specimens. The factors (MIG/MAG shielding gas type, MIG/MAG voltage, MIG/MAG wire feed, gas flow rate of TIG, electric current intensity of TIG and welding speed) were varied with three levels each. Penetration, heat-affected zone (HAZ), bead width and bead height were the response variables analyzed. The results showed that the penetration was significantly influenced by the MIG/MAG wire feed, MIG/MAG shielding gas type, MIG/MAG voltage and welding speed. The HAZ has been influenced by MIG/MAG voltage, MIG/MAG shielding gas type, welding speed and electric current intensity of TIG. All factors had effects on the width, except the MIG/MAG wire feed. The bead height was significantly influenced by the MIG/MAG wire feed and by the electric current intensity of TIG. Optimizing the process was performed, so that for each output variable, the values of the factors that should be used were indicated, and the optimization was confirmed by welding test specimens.
Comparison of the Percentage of Voids in the Canal Filling of a Calcium Silicate-Based Sealer and Gutta Percha Cones Using Two Obturation Techniques
Authors: Kim Sohee , Kim Sunil , Park Jeong-Won , Jung Il-Young , Shin Su-Jung
Published: October 2017

This study evaluated the root-filling quality of a calcium silicate-based sealer and gutta percha (GP) cones by measuring the percentage of voids. Twenty artificial molar teeth were divided into two groups: one obturated using the single-cone (SC) technique, and the other using the continuous wave (CW) technique. Obturation was performed with GP cones and Endoseal MTA (mineral trioxide aggregate, Maruchi, Wonju, Korea). Obturated teeth were scanned using microcomputed tomography, and the percentage of void volume was calculated in the apical and coronal areas. A linear mixed model was used to determine the differences between the two techniques (p < 0.05). The percentage of voids between the filling materials and root canal walls was not significantly different between the two obturation methods (p > 0.05), except for the CW group, which demonstrated a significantly higher void volume in the coronal area of the distal canal (p < 0.05). The percentage of voids inside the filling material was significantly higher in the CW groups for all of the comparisons (p < 0.05), except in the apical area of the distal canal (p > 0.05). The voids between the filling material and canal wall in the apical area were not significantly different between the two techniques.
Formation of Nanoscale Metallic Glassy Particle Reinforced Al-Based Composite Powders by High-Energy Milling
Authors: Zhang Weiwen , Hu Yuan , Zhang Guanqun , Wang Zhi
Published: October 2017

The initial microstructure and mechanical properties of composite powders have a vital role in determining the microstructure and mechanical properties of the subsequent consolidated bulk composites. In this work, Al-based matrix composite powders with a dense and uniform distribution of metallic glass nanoparticles were obtained by high-energy milling. The results show that high-energy milling is an effective method for varying the microstructure and mechanical properties of the composite powders, thereby offering the ability to control the final microstructure and properties of the bulk composites. It was found that the composite powders show a deformed layer combined with an undeformed core after milling. The reinforcements, metallic glass microparticles, are fractured into dense distributed nanoparticles in the deformed layer, owing to the severe plastic deformation, while in the undeformed core, the metallic glass microparticles are maintained. Therefore, a bimodal structure was obtained, showing a mechanical bimodal structure that has much higher hardness in the outer layer than the center core. The hardness of the composite particles increases significantly with increasing milling time, due to dispersion strengthening and work hardening.
A Micro-Force Sensor with Beam-Membrane Structure for Measurement of Friction Torque in Rotating MEMS Machines
Authors: Liu Huan , Yu Zhongliang , Liu Yan , Fang Xudong
Published: October 2017

In this paper, a beam-membrane (BM) sensor for measuring friction torque in micro-electro-mechanical system (MEMS) gas bearings is presented. The proposed sensor measures the force-arm-transformed force using a detecting probe and the piezoresistive effect. This solution incorporates a membrane into a conventional four-beam structure to meet the range requirements for the measurement of both the maximum static friction torque and the kinetic friction torque in rotating MEMS machines, as well as eliminate the problem of low sensitivity with neat membrane structure. A glass wafer is bonded onto the bottom of the sensor chip with a certain gap to protect the sensor when overloaded. The comparisons between the performances of beam-based sensor, membrane-based sensor and BM sensor are conducted by finite element method (FEM), and the final sensor dimensions are also determined. Calibration of the fabricated and packaged device is experimentally performed. The practical verification is also reported in the paper for estimating the friction torque in micro gas bearings by assembling the proposed sensor into a rotary table-based measurement system. The results demonstrate that the proposed force sensor has a potential application in measuring micro friction or force in MEMS machines.
Periodic TiO2 Nanostructures with Improved Aspect and Line/Space Ratio Realized by Colloidal Photolithography Technique
Authors: Berthod Loïc , Shavdina Olga , Verrier Isabelle , Kämpfe Thomas , Dellea Olivier , Vocanson Francis , Bichotte Maxime , Jamon Damien , Jourlin Yves
Published: October 2017

This paper presents substantial improvements of the colloidal photolithography technique (also called microsphere lithography) with the goal of better controlling the geometry of the fabricated nano-scale structures—in this case, hexagonally arranged nanopillars—printed in a layer of directly photopatternable sol-gel TiO2. Firstly, to increase the achievable structure height the photosensitive layer underneath the microspheres is deposited on a reflective layer instead of the usual transparent substrate. Secondly, an increased width of the pillars is achieved by tilting the incident wave and using multiple exposures or substrate rotation, additionally allowing to better control the shape of the pillar’s cross section. The theoretical analysis is carried out by rigorous modelling of the photonics nanojet underneath the microspheres and by optimizing the experimental conditions. Aspect ratios (structure height/lateral structure size) greater than 2 are predicted and demonstrated experimentally for structure dimensions in the sub micrometer range, as well as line/space ratios (lateral pillar size/distance between pillars) greater than 1. These nanostructures could lead for example to materials exhibiting efficient light trapping in the visible and near-infrared range, as well as improved hydrophobic or photocatalytic properties for numerous applications in environmental and photovoltaic systems.
Effect of Nanoparticles on the Morphology, Thermal, and Electrical Properties of Low-Density Polyethylene after Thermal Aging
Authors: Wang Youyuan , Wang Can , Zhang Zhanxi , Xiao Kun
Published: October 2017

This paper investigates the morphology, thermal, and electrical properties of LDPE (low-density polyethylene)-based nanocomposites after thermal aging. The FTIR (Fourier transform infrared spectroscopy) spectra results show that thermo-oxidative reactions occur in neat LDPE and LDPE/SiO2 nanocomposites when the aging time is 35 days and in LDPE/MgO nanocomposites when the aging time is 77 days. Specifically, LDPE/MgO nanocomposites delay the appearance of thermo-oxidative reactions, showing anti-thermal aging ability. Furthermore, nanocomposites present lower onset degradation temperature than neat LDPE, showing better thermal stabilization. With regard to the electrical properties, nanocomposites maintain the ability to suppress space charge accumulation after thermal aging. Additionally, in comparison with SiO2 nanocomposites and neat LDPE, the permittivity of LDPE/MgO nanocomposites changes slightly after thermal aging. It is concluded that LDPE/MgO nanocomposites have better insulation properties than neat LDPE after thermal aging, which may be caused by the interface introduced by the nanoparticles.