bluuebunny/crossref_metadata_2025 huggingface dataset:
Wet Chemical Synthesis of Germanium Nanocrystals
Authors: Lu Xianmao , Korgel Brian A. , Johnston Keith P.
Published: June 2019

Supercritical CO2 (sc-CO2) was first time utilized to make germanium (Ge) nanocrystals by thermolysis of diphenylgermane (DPG) or tetraethylgermane (TEG) with octanol as capping ligand at 500°C and 27.6 MPa. A new approach to prepare Ge nanocrystals of high chemical yield by reduction of GeI2 with LiAlH4 in trioctylphosphine (TOP) at 300°C is also presented. In both cases, Ge nanoparticles with high crystallinity were observed with high resolution transmission electron microscopy (HRTEM), and the presence of Ge was confirmed by X-ray diffraction (XRD) pattern. Compared to the supercritical organic solvents investigated in the previous study to make Ge nanoparticles, the reaction in sc-CO2 produced much less organic contaminants and made the removal of by-products and cleaning of the nanocrystals much easier. While Ge nanoparticles were synthesized in sc-CO2 with DPG and octanol, bulk Ge instead of nanoparticles was obtained without the presence of CO2 at the same concentration of DPG and octanol. High chemical yield of up to 75% was achieved for the Ge nanoparticles made from GeI2 with TOP, and only minimal cleaning is required to obtain Ge nanocrystals with high purity.
Depth Profiling of Mechanical Properties on the Nanoscale of Single-Layer and Stepwise Graded DLC Films by Nanoindentation and AFM
Authors: Ziebert C. , Ulrich S. , Stüber M.
Published: June 2019

The strong ion bombardment, applied during sputter deposition of diamond-like carbon films (DLC), which is needed to promote the growth of the sp3-bonded hard phase, inevitably is accompanied by compressive stress generation, thus limiting their maximum thickness. Gradient coatings with gradients in composition, constitution or properties are a well-known concept to manage such stress problems. The stepwise graded layer concept adjusts a graded constitution of the growing carbon film by a stepwise increase of the ion energy, i.e. the substrate bias voltage, during magnetron sputtering. To study the influence of the layer thickness on the expansion of the interface regions between the layers deposited with different bias voltage, samples with increasing deposition time of the top layer and thus thickness ratio were investigated by using the small angle cross-section nanoindentation method (SACS). It was revealed that the thickness of the interface regions is linearly dependent on the thickness ratio of the graded layers, which might be an evidence for stress-induced diffusion and relaxation processes in the carbon network. By using microindentation with a Berkovich indenter and ex-situ AFM-imaging it was found that all graded films exhibited higher Berkovich thresholds for crack development and thus better crack resistance than the hardest single-layer film and kept a high hardness value of about 4000 HV0.005.
Deformation of Highly Loaded Alumina Reinforced Aluminium Composites: Internal Damage and the Size Effect
Authors: Müller Randoald , Mortensen Andreas
Published: June 2019

The pressure infiltration of densely packed alumina particle preforms with molten aluminium produces defect-free composites containing roughly equal proportions of metal and ceramic. The process affords considerable latitude in microstructural design of the resulting composites. In particular, the matrix can be kept microstructurally simple, and the size of the reinforcement can be varied roughly between 3 and 100 μm.

Despite their high ceramic loadings, these composites display appreciable plasticity, often deforming in tension to elongations of several percent before breaking. Beyond yield, their flow stress is largely governed by that of the matrix; this matrix, in turn, is a metal deforming between hard inclusions only a few micrometres apart. As is known from the composite literature, the high constraint imposed by the reinforcement on matrix deformation is manifest in a “size-effect”, whereby the matrix flow stress, and hence that of the composite, depend on the microstructural scale of the composite, increasing as the reinforcement size decreases.

We present recent results on this phenomenon from an investigation of pressure-infiltrated alumina reinforced aluminium composites. The composites are model materials in that (i) their matrix (high-purity aluminium, or binary aluminium-copper alloys) is kept metallurgically simple, (ii) the matrix/reinforcement interface is mechanically strong and free of interfacial reaction products, and (iii) the reinforcement is monosized and uniformly distributed throughout the composite.

We describe a method of data analysis of this effect that takes into account both the complexity of the underlying mechanical problem and the influence of internal damage, which often develops extensively in such materials. Recent results for the non-linear deformation of power-law composites are used in conjunction with measurements of the rate of internal damage in these materials to derive in-situ flow curves of the matrix within such composites. Results show that there is a strong and systematic size effect for yield and plastic flow of highly reinforced pure aluminium; data also show an influence of the particle shape in additional to particle size. With binary Al-Cu alloys, the data show that there is a size effect on yield of the composite, but not on the flow stress upon subsequent deformation.
Mechanical Properties of Textured Alumina Prepared by Colloidal Processing in a Strong Magnetic Field
Authors: Suzuki Tohru S. , Uchikoshi Tetsuo , Morita Koji , Hiraga Keijiro , Sakka Yoshio
Published: June 2019

The development of texture can be controlled by slip casting and EPD in a strong magnetic field followed by heating even for diamagnetic ceramics such as alumina. We mesured the mechanical properties of the textured alulmina and the alumina/alumina laminar composites with different crystalline-oriented layer.
Synthesis and Characterization of Layered Double Hydroxides/Nafion Composites for Fuel Cell Application
Authors: Raghavan Dharmaraj , Abayomi Bolnale , Harewood Miriam , Abudu Sheriff , Williams Elizabeth , Butcher Raymond , Raghavan Dharmaraj
Published: June 2019

In this study, magnesium-aluminum (Mg-Al) based LDHs with different Mg2+/Al3+ ratios were prepared by co-precipitation method and modified with perfluorooctane-sulfonic acid tetraethylammonium salt (PFOSA). X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), Fourier Transfer Infrared spectroscopy (FTIR) and Thermogravimetric Analysis (TGA) were carried out to obtain the structural and thermal characteristics of resulting materials. The organo-modified LDHs have been used in the formulation of Nafion® nanocomposites. Nanocomposite membranes were prepared by casting of LDH/PFOSA nanoparticles dispersed in Nafion® solution. Then, modified LDH/Nafion composite membranes were evaluated for water retention capability at ambient and elevated temperature.
Uniform Accuracy of the Quasicontinuum Method [PowerPoint Submission]
Authors: Yang Jerry Z.
Published: June 2019

The accuracy of the quasicontinuum method is studied by reformulating the summation rules in terms of reconstruction schemes for the local atomic environment of the representative atoms. The necessary and sufficient condition for uniform first order accuracy and consequently the elimination of the “ghost force” is formulated in terms of the reconstruction schemes.

The quasi-nonlocal approach is discussed as a special case of this condition.

Examples of reconstruction schemes that satisfy this condition are presented.

Transition between atom-based and element-based summation rules are studied.
Computer Simulation of Fracture in Aerogels
Authors: Good Brian
Published: June 2019

Aerogels are of interest to the aerospace community primarily for their thermal properties, notably their low thermal conductivities. While the gels are typically fragile, recent advances in the application of conformal polymer layers to these gels has made them potentially useful as lightweight structural materials as well. In this work, we investigate the strength and fracture behavior of silica aerogels using a molecular statics-based computer simulation technique. The gels' structure is simulated via a Diffusion Limited Cluster Aggregation (DLCA) algorithm, which produces fractal structures representing experimentally observed aggregates of so-called secondary particles, themselves composed of amorphous silica primary particles an order of magnitude smaller. We have performed multi-length-scale simulations of fracture in silica aerogels, in which the interaction between two secondary particles is assumed to be described by a Morse pair potential parameterized such that the potential range is much smaller than the secondary particle size. These Morse parameters are obtained by atomistic simulation of models of the experimentally-observed amorphous silica “bridges,” with the fracture behavior of these bridges modeled via molecular statics using a Morse/Coulomb potential for silica. We consider the energetics of the fracture, and compare qualitative features of low-and high-density gel fracture.
Void Evolution via Coupled Creep, Diffusion and Electromigration in Confined Nano-interconnects
Authors: Kim Dongchoul , Lu Wei
Published: June 2019

A three dimensional electromigration model is presented to account for void evolution in small scale interconnects. The model provides better understanding of the evolution process by considering concurrent kinetics of creep flow and surface diffusion. The multiple kinetics and energetics are incorporated into a diffusive interface model. Simulations show that a shape stable in surface diffusion can become unstable in a creep dominated process, which leads to a quite different void morphology.
Interplay of Shock-induced Melting and Alloying in Nanostructured Multilayer Films
Authors: Zhao Shijin , Germann Timothy C. , Strachan Alejandro
Published: June 2019

We identify a shock-induced melting and great facilities of the melting in accelerating subsequent alloying reactions in nanostructured Ni/Al multilayer films using a novel molecular dynamics technique, which captures the initial shock transit as well as the subsequent long time scale alloying process. We observe a pronounced increase of the pressure in the melting process (i.e., a process of coexistence of solid and liquid phases). As soon as the melting completes, the temperature increases dramatically indicating a start of explosive alloying reactions and the pressure starts to decrease. The pressure going up or down is determined by the competition between melting and alloying reactions.
Role of Trapping Impurities on He Desorption and Clustering in Irradiated α-Fe [PowerPoint Submission]
Authors: Ortiz Christophe J. , Caturla Maria Jose , Fu Chu Chun , Willaime Francois
Published: June 2019

It is well-known that impurities affect the migration of intrinsic point defects in metals. For instance, carbon is a common impurity in Fe that significantly retards diffusion of vacancies. Under fusion irradiation conditions, high levels of He are produced by transmutation reactions. This element strongly interacts with vacancies produced during irradiation and agglomerate into stable He-vacancy clusters that can deteriorate the mechanical properties of the material. A physically-based model accounting for the interactions between He, point defects (interstitials and vacancies) and trapping impurities is therefore necessary to understand and predict damage evolution in Fe.

We have used a multi-scale approach to predict the evolution of He in the presence of impurities in irradiated Fe. Density Functional Theory (DFT) calculations were performed to investigate the migration mechanisms and to determine the activation energies of the different atomistic processes. The influence of impurities - such as carbon - on the binding energies of small He-vacancy clusters was also studied. Using the information obtained by DFT a physically-based model was developed and implemented in a kinetic Monte Carlo (kMC) code to follow the evolution of He in Fe. In addition, a model based on the rate theory (RT) was developed in order to achieve larger simulation times and volumes. Results obtained with this model, which is based on a mean field approximation are compared to those obtained with kMC. Using this multiscale approach, the simulation results are used to interpret the different stages of thermal He desorption experiments and to determine the predominant migration mechanism. The influence of impurities which affect the diffusion of point defects or modify the binding energies of He-vacancy type clusters is also studied.
Systematic Coarse-graining and Multiscale Modeling of Soft Matter [PowerPoint Submission]
Authors: Voth Gregory A.
Published: June 2019

A multiscale theoretical and computational methodology will be presented for describing liquid state, biomolecular, and nanoparticle systems across multiple length- and time-scales. The approach provides an interface between atomistic molecular simulations, mesoscale dynamics, and continuum mechanics. The underlying methodology couples atomistic-level simulations with mesoscale simulations which, in turn, can be bridged to continuum-level modeling where necessary. A new and systematic multiscale coarse-graining strategy for linking the atomistic-scale interactions to the mesoscale will be the primary focus of the presentation. Applications of the overall methodology will be given.
Hierarchical nanomechanics of vimentin alpha helical coiled-coil proteins
Authors: Ackbarow Theodor , Buehler Markus J.
Published: June 2019

Coiled-coil alpha-helical dimers are the elementary building blocks of intermediate filaments (IFs), an important component of the cell's cytoskeleton. Therefore, IFs play a leading role in the mechanical integrity of the cells. Here we use atomistic simulation to carry out tensile tests on coiled-coils as well as on single alpha-helices of the 2B segment of the vimentin dimer that has been shown to control the large-deformation behavior of cells. We compare the characteristic force-strain curves of both structures and suggest explanations for the differences on this fundamental level of hierarchical assembly. We further systematically explore the strain rate dependence of the mechanical properties of the vimentin coiled-coil protein. We develop a simple continuum model capable of reproducing the atomistic modeling results. The model enables us to extrapolate to much lower deformation rates approaching those used in experiment.
Influence of Mineral -Polymer Interactions on Molecular Mechanics of Polymer in Composite Bone Biomaterials
Authors: Bhowmik Rahul , Katti Kalpana S , Katti Dinesh R
Published: June 2019

Nanocomposite bone materials of polymers and hydroxyapatite are widely investigated for bone replacement. The mechanical properties of the composites determine the use of these as implant materials. The molecular phenomenon at the interface between mineral and polymer is known to have significant contribution on overall mechanical response of composites. Understanding behavior of interfaces under applied load, and the load transfer mechanisms will lead to development of superior biomaterial composites with desired properties. We have performed Steered Molecular Dynamics (SMD) simulations on the composite system consisting of hydroxyapatite and polyacrylic acid. Our simulations describe the detailed molecular mechanisms responsible at the interface with applied load. Our SMD simulations also indicate that the polymer shows significant changes when it interacts with the mineral. The load-deformation behavior of polymer has shown that the polymer is stiffer when it is interacting with mineral. The binding and unbinding events are also calculated during load transfer in polymer. This work describes specific molecular mechanism responsible for mechanical behavior in composites used as bone biomaterials.
Electroplated and Plasma Enhanced Magnetron Sputtered Ta and Cr Coatings for High Temperature and High Pressure Operation
Authors: Lee Sabrina L. , Wei Rong H. , Todaro Mark , Cote Paul
Published: June 2019

For A723 steel large caliber gun barrel applications, high pressure (∼700MPa), rapid cyclic heating-cooling (∼1250°C), and aggressive propellant gases (CO, CO2, H2O, H2, N2, NH3, CH4, H2S etc) operational environment can cause severe wear and erosion damages to the bore, reducing the service life of the component. Refractory bore coatings can help protect the steel bore to extend service life. Cr electroplating process is currently being widely used in industry and in the military, but toxic wastes from the process are difficult and expensive to dispose. Plasma enhanced magnetron sputtering techniques are being developed for potential replacement of the Cr electroplating process. In this work, we compared A723 steel specimens coated with electroplated Cr and plasma enhanced magnetron sputtered Ta and Cr coatings. The specimens were subjected to analytical testing, including scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, metallography; and adhesion testing, including groove test, a pulsed laser heat test to simulate cyclic thermal environment of the bore, and actual firing test. Steel samples electroplated with HC (high contraction) Cr showed extensive pre-deposition cracks, it also showed cohesive failures under groove adhesion test. When subjected to cyclic high pressure and temperature operation, gas-metal interactions led the as-deposited cracks to grow wider and new cracks to develop, allowing hot pressurized propellant gases to penetrate the cracks and erode the steel substrate. Plasma enhanced sputtered Ta and Cr coatings on steel were harder and denser compared to conventional magnetron sputtered coatings. Under groove testing, they showed no cracks, no cohesive and no adhesive failures. When subjected to cyclic pulsed laser heating simulation at 1490°K, thick sputtered Ta showed no crack, no delamination, and no failures. A heat affected zone was observed in steel, which was caused by tempered to untempered martensite conversion. Our data also showed that Ta sputtered in Ar consisted of minimum interface meta-stable tetragonal Ta fingers, which converted to bcc Ta in the heat affected zone; Ta sputtered in Kr consisted of 100% stable bcc Ta under similar experimental conditions.
Pressure-Induced Phase Transformations in Li-based Complex Hydrides
Authors: Chellappa Raja , Chandra Dhanesh , Gramsch Stephen , Somayazulu Maddury , Hemley Russell
Published: June 2019

An overview of the pressure-induced transformations and order-disorder phenomena in LiAlH4 (up to 7 GPa) and LiNH2 (up to 25 GPa) are presented. The analysis of pressure-induced changes in Raman spectra suggest a phase transition at ∼3 GPa for LiAlH4 and ∼14 GPa for LiNH2. New results on the metastable recovery of the high pressure β-LiAlH4 phase are also presented. An examination of the lattice translational and librational modes reveals that the high pressure β-LiAlH4 phase is disordered while there is evidence of orientational ordering in the high pressure beta-LiNH2 phase.
FIRST BREEDING RECORD OF PINTADO PETREL DAPTION CAPENSIS AT MARION ISLAND
Authors: Masotla Makhudu Josiah
Published: June 2019

Pintado or Cape Petrels Daption capense have a circumpolar distribution and have been recorded breeding at 23 localities in the Southern Ocean. They have been recorded as vagrants to Marion Island since 1951. Oosthuizen et al. (2009) regarded them as occurring too frequently for the species to be regarded as a vagrant, but was never thought to be breeding there. This is the first record of the species breeding at the PEIs and brings the number of seabird species, including the Lesser Sheathbill, reported breeding there to 31.
Predation of porcupine Hystrix africaeaustralis in the den by honey badger Mellivora capensis
Authors: Arbon Kate
Published: June 2019

A porcupine (Hystrix africaeaustralis) den was placed under observation by camera trap, and subsequently a honey badger (Mellivora capensis) was recorded raiding the den to prey on the young porcupines inside.
Pierre Bourdieu og den sociologiske tænkning om læreren (subjektivitet og socialitet)
Authors: Callewaert Staf
Published: June 2019

Vort tema har titlen "lærerpersonligheden". For mig er det ikke så klart hvad der kan menes med det. Med ordet lærer plejer man jo i første omgang at antyde indehaveren af en erhvervsrolle og en funktionærstatus, samt en lønarbejder­status inden for rammen af det formelle uddannelsessystem i offentlig regi, dvs. folkeskolelærer, gymnasielærer, universitetslærer. Men man forlader ikke hverdagssproget hvis man anvender ordet i en bredere mening om alle som formidler en viden eller en kunnen.

       Sagen kompliceres desuden straks af at den vægt vi lægger på formidling af kundskaber og færdigheder, klart nok gerne associeres med ordet lærer, men selve den rolle som ordet betegner, er også associeret med opdragelse, dvs. med noget som er bredere.

            Hvad kan man så mene med ordet personlighed? Det er straks sværere at svare på det. Hverdagssproget betegner med dette per definition noget i retning af det konkrete individ, opfattet som et samlet centrum for handling i videste mening, som udviser en vis kontinuitet i tid og rum. Videre kan man sige at ordet personlighed associeres med en specifik måde at være et sådant centrum på, måske tilmed en unik måde at være det. Dette har desuden en slags indre dimension som ikke er direkte tilgængelig ud over gennem personlighedens manifestationer: den jeg oplever at være indefra, jeg som oplever centrum ikke bare for handling, men som den plads hvor jeg oplever mig selv (subjektivitet). Og det har en social dimension som i sig selv er mangfoldig: både jeg og du, jeg og vi, interindividuel og supraindividuel (socialitet).
Form-finding approach for flexibly formed concrete elements
Authors: Kostova Kaloyana , Ibell Tim , Darby Antony , Evernden Mark
Published: June 2019

There is no reason why concrete elements should be prismatic. Concrete is mouldable and can be cast in efficient forms which follow the stresses varying along the length of a concrete element. One option to achieve this is to use fabric as flexible formwork. Fabric deforms under the hydrostatic pressure exerted by wet concrete during construction, creating the shape of hardened concrete. The final shape needs to be known in advance to be able to perform the analysis and design of structural elements. This paper presents a form-finding approach capable of predicting the shape in cross-section of flexibly formed concrete elements. The approach is shown to predict geometry appropriately, based on the results of an experimental investigation, particularly when applied to complex shapes. The influence of construction tolerances, practical aspects and limitations of the approach are also discussed.
Liberación de oxígeno radial por las raíces de las plantas nativas de humedales tropicales costeros de Veracruz en respuesta a diferentes condiciones de inundación
Authors: Sánchez-Olivares Evelyn , Marín-Muñiz Jose Luis , Hernandez-Alarcón Maria Elizabeth
Published: June 2019

Antecedentes: La liberación de oxígeno por las plantas de humedales es un proceso fisiológico que oxigena el sedimento favoreciendo la actividad de los microorganismos aeróbicos, dicha actividad impacta los servicios ambientales de los humedales. Poco se sabe sobre la liberación de oxígeno por las plantas nativas de los humedales de México.Preguntas: ¿Cuál de las macrófitas más abundantes de los humedales de Veracruz, presenta la mayor liberación de oxígeno radial? y ¿Las condiciones de inundación tienen algún efecto en la liberación de oxígeno radial de las macrófitas nativas de los humedales costeros?Área de estudio: Veracruz, México.Métodos: Se mido la producción y porosidad de la raíz, y la liberación de oxígeno por el método de citrato de titanio en 7 de las especies nativas de los humedales de Veracruz, crecidas bajo tres condiciones hidrológicas: capilaridad, saturación e inundación.Resultados: Las especies con mayor peso y volumen de raíz ( Pontederia sagittata, Sagitaria lancifolia y Thalia geniculata ) mostraron bajas liberaciones de oxígeno radial en base a peso seco. La liberación de oxígeno por planta bajo condiciones de inundación mostró diferencias significativas entre las especies, Typha domingensis mostró mayor liberación de oxígeno (148 ±46 µmol O2 d-1) y Leersia ligularis la menor (22 ± 46 µmol O2 d-1). Conclusión: La inundación ocasionó una disminución en la producción de biomasa de las raíces de las plantas nativas de los humedales de Veracruz, un aumento en la porosidad y estimuló la libración de oxígeno por planta, encontrándose diferencias significativas entre las plantas estudiadas.
Establishment of efficient adventitious shoots induction system and ex vitro rooting in Vaccinium corymbosum (Ericaceae)
Authors: Wang Ye , Dong Xian , Huang Heng-Yu , Wang Yuan-Zhong
Published: June 2019

Background: The extension of the blueberry industry in China is restricted by the low performance of proliferation coefficient, transplanting survival rate and the long cycle production.Hypothesis: We hypothesized the suitable medium with optimal concentration and type combination would improve the survival rate of Vaccinium corymbosum. Species studied: Vaccinium corymbosum L. cultivar ‘O’Neal.Study site and years of study: Our study was conducted in Yunnan Breeding and Cultivation Research and Development Center of Endangered and Daodi Chinese medicinal materials, Yunnan University of Chinese Medicine since November 2015.Methods: Efficient protocol of plant regeneration about Southern highbush blueberry (cultivar ‘O’Neal) was established using annual shoots via single factor and orthogonal experiments.Results: Olive medium with 2.0 mg·L-1 zeatin was found to be most suitable for initiation culture. The highest callus induction and bud formation rate were determined with 93.67 % and 95.57 %, respectively. Furthermore, as the germination of axillary buds, numerous shoots were formed with the proliferation coefficient (> 60). Well-developed shoots were obtained using rejuvenation culture on half-strength Olive medium supplemented with combination of 2.0 mg·L-1 indole-3-butyric acid, 1.0 mg·L-1 naphthaleneacetic acid, 0.01 mg·L-1 chlormequat chloride and 0.5 g·L-1 activated charcoal. The rooting rate could reach to 100 % using 2 cm length of well-developed shoots transferred into the 5:1 sterilized peat:perlite, which was enhanced from 27.61 up to 95 % after transplanting to the field.Conclusions: An efficient system for plant regeneration from bud induction to transplanting to the field was established to maintain the characteristics of southern highbush blueberry varieties.
Analysis of the performance profile of the NCERD thermosyphon solar water heater
Authors: Agbo Solomon
Published: June 2019

The work reported here is the performance profile of a thermosyphon solar water heater developed by the National Centre for Energy Research and Development (NCERD), University of Nigeria, Nsukka. The performance evaluation was based on the mathematical models that describe the test system and some measured experimental data. The effect of some of the design and operating parameters that have been shown to affect the system’s performance was investigated. The parameters considered included the number of glazing covers, glazing cover thickness, tube spacing and the nature of absorber plate material. The performance results indicate that the test system has a maximum average daily collector efficiency of 0.658 and a mean system temperature of 81oC. The efficiency of the collector drops to an average seasonal value of 0.54 with a negligible variation across the three climatic seasons was covered in the study. With a tube spacing not exceeding 10 cm, the performance of the system is optimized irrespective of the nature of the absorber plate material. We found that the number of glazing covers affects the top-loss coefficient of the system depending on the type of absorber plate used. Multiple glazing shows a negligible contribution especially for low temperature application. The glazing cover thickness does not affect the performance of the system significantly.
Experimental study on heat and mass transfer for heating milk
Authors: Kumar Mahesh , Kasana K.S. , Kumar Sudhir , Prakash Om
Published: June 2019

In this paper, an attempt has been made to estimate the convective heat transfer coefficient for sensible heating of milk in a stainless steel pot during khoa, made by traditional method. Various indoor experiments were performed for simulation of a developed thermal model for maximum evaporation by varying heat inputs from 240 watts to 420 watts. The experimental data was used to determine values of constants in the well known Nusselt expression by simple linear regression analysis and, consequently, convective heat transfer coefficients were determined. It is found that the convective heat transfer coefficients decrease with an increase in rate of heating. The experimental error in terms of percent uncertainty was also evaluated.
What is the carbon emission factor for the South African electricity grid?
Authors: Spalding-Fecher Randall
Published: June 2019

One of the most important parameters for developing Clean Development Mechanism (CDM) project proposals in the electricity sector (both supply and efficiency) is the standard electricity ‘grid emission factor’, which represents the carbon dioxide related to a megawatt hour of electricity supplied or saved on the grid. While there are detailed guidelines from the CDM Executive Board on how to calculate this emission factor, the values used in registered CDM projects in South Africa vary widely, both due to changes in the rules over time and also to misapplication of the rules. This paper shows how the application of the latest guidelines gives a ‘combined margin emission factor’ for South Africa of 0.957 tCO2/MWh in 2009/2010. The variation in emission factors in the literature, as well as the importance of reducing the transaction costs for South African project developers, points to the need for an official published grid emission factor from the CDM host country authority in South Africa, the Designated National Authority (DNA), within the Department of Energy.
Estimating greenhouse gas emissions associated with achieving universal access to electricity for all households in South Africa
Authors: Tait Louise , Winkler Harald
Published: June 2019

Climate change, energy security and achieving universal electricity access for all households are all pressing issues that South Africa must address. These objectives need not be trade-offs, however, and achieving electricity access for the poor does not justify the building of large coal-fired power stations or threaten South Africa’s climate change objectives. This paper estimates the electricity demand from the residential sector to 2020 resulting from universal access, and finds that electricity for low-income households would constitute only a small addition to total electricity demand and would represent only a minor portion of output from the coal-fired power station, Medupi. Furthermore, emissions from the additional electricity consumed by newly connected households would have a negligible impact on South Africa’s emissions profile.
A techno-economic model for optimising component sizing and energy dispatch strategy for PV-diesel-battery hybrid power systems
Authors: Hove Tawanda , Tazvinga Henerica
Published: June 2019

This paper presents the development and application of a simple spreadsheet-based simulation model for sizing, energy performance evaluation and economic analysis of PV-diesel-battery power supply systems. The model is employed to generate a set of sizing curves that define the design space for hybrid systems using dimensionless generator component size variables, for a specified supply reliability and diesel energy dispatch strategy. The component size combination with the least unit cost of energy is selected among the many possible combinations satisfying a desired loss-of-load probability. Storage battery and diesel generator lifespan, as well as generator fuel efficiency, which depend on the operational loading stress of these components, are recognised as important variables in the economics of the system. The lifespan of the battery is premised to depend on the depth and rate of discharge of the operating cycles, while both the diesel generator lifespan and fuel efficiency are dependent on the degree and frequency of partial loading. The choice of diesel generator dispatch strategy was shown to be another important factor influencing the energy performance and economics of the system. The outputs of the model reveal several important sizing, operational and economic characteristics of the systems, and enables appraisal of comparative advantage of different types of designs and operational strategies. The merits of the hybrid concept are well demonstrated by the study results.
Functional Outcomes of Thoracolumbar Junction Spine Fractures
Authors: Wall Bradford A. , Moskowitz Alan , Whitaker M. Camden , Jones Teresa L. , Stuckey Ryan M. , Carr-Maben Catherine L. , Chong Alexander CM.
Published: June 2019

Introduction. Few studies have evaluated the functionaloutcomes of traumatic thoracic and lumbar vertebral bodyfractures. This study evaluated the functional and clinicaloutcomes of patients, who sustained a fracture to thethoracolumbar area of the spine (T10 to L2 region), with≥ 25° kyphosis versus those with less kyphotic curvature.

Methods. The trauma registry records of two level 1 traumacenters using ICD-9 codes for fracture to the thoracolumbarjuncture (T10 to L2 region) were reviewed. Kyphosis anglewas measured on the standing lateral thoracolumbar (T1 -L5) radiograph at initial trauma and at clinical follow-up.Functional outcome questionnaires, including the OswestryDisability Questionnaire (ODQ), the Roland Morris DisabilityQuestionnaire (RMDQ), and the Nottingham Health Profile(NHP), were evaluated at clinical follow-up. Work statusand medication used after trauma also were recorded.

Results. A total of 38 patients met the inclusive criteria. Seventeenpatients (45%) had ≥ 25° kyphosis and 21 patients (55%)had < 25° kyphosis at follow-up. These two groups were similarbased on sex and age. Based on the ODQ Score, the RMDQScore, and the NHP, no statistically significant differenceswere detected between the two groups in regards to energy,pain, mobility, emotional reaction, social isolation, and sleep.

Conclusions. Patients who sustained a fracture to the thoracolumbararea of the spine with ≥ 25° kyphosis do notreport worse clinical outcomes. When using the kyphosisangle as an indication for surgery, it should be used withcaution and not exclusively. KS J Med 2017;10(2):30-34.
Safe Sleep Knowledge and Use of Provided Cribs in a Crib Delivery Program
Authors: Engel Matthew , Ahlers-Schmidt Carolyn R. , Suter Bonita
Published: June 2019

Introduction. Risk of infant sleep-related death can be reducedthrough safe sleep practices. Barriers to infant safe sleep have beenmitigated through education and crib distribution, however, previousstudies have not explored whether distributed cribs are put to use.

Methods. In a rural Michigan county, the Great Start Sleep Initiativesupplied cribs and education shortly after infant birth to familieswith high-risk of infant mortality, as assessed through comprehensiveinterviews with families by program staff. Participant knowledgewas evaluated using structured pre- and post-assessments beforeand after education. Further, a home visit was conducted to evaluatethe infant’s sleeping environment. Data from the program, collectedbetween January 2012 and December 2014, were evaluated.

Results. Cribs and concomitant education were delivered to 75caregivers. Knowledge of safe sleep practices increased significantlyat follow-up with 67 caregivers (89%) affirming back positioning,68 (91%) endorsing removal of unsafe items or soft objects, suchas blankets, from the sleeping area, and 42 (56%) renouncing bedsharing.At the home visit, 74 caregivers (99%) were using a crib toput their infant down to sleep, 70 (93%) were using the providedcrib, and 67 (89%) had no unsafe items in the child’s sleeping area.

Conclusion. Providing education to high-risk mothersresulted in improved safe sleep knowledge and providedcribs are used in these homes. KS J Med 2017;10(3):59-61.
Elastic Abdominal Binders Reduce Cesarean Pain Postoperatively
Authors: Gustafson Jamie L. , Dong Fanglong , Duong Jennifer , Kuhlmann Zachary C.
Published: June 2019

Introduction. A potential non-pharmacologic way to reduce postoperativepain and bleeding is using an abdominal binder duringpostoperative recovery. This study aims to determine the effect anelastic abdominal binder has on postoperative pain and hemorrhageafter cesarean delivery.

Methods. A randomized, single-site, pilot trial was conducted at twoprenatal care clinics and an academic hospital in Kansas. Beginningin April 2013, 60 patients were enrolled if delivering via cesarean.Participants were randomized to receive an abdominal binder or to acontrol group (did not use binder). Pain levels were reported by questionnaireone day after surgery using a 0 to 10 scale, with 10 being theworst pain. Patient characteristics and blood loss were assessed bymedical record review.

Results. Of the 56 patients completing the study, 29 (51.8%) wererandomized to the binder group and 27 (48.2%) were randomizedto the control group. The binder group reported significantly lowerpain score (p = 0.019) and average pain score (p = 0.024). There wasno difference in body mass index, age, previous surgery, infant birthweight, estimated blood loss, and average dose of pain medicationduring the first 24 hours after the cesarean delivery between the twogroups. There was no difference in pre- and post-operative hemoglobinlevels by treatment group (p = 0.406).

Conclusions. Abdominal binders may be associated with improvedpostoperative pain scores but did not affect postoperative hemorrhage.Kans J Med 2018;11(2):48-53.
El principio de oportunidad ¿modernización o crisis del derecho penal?
Authors: Olaizola Nogales Inés
Published: June 2019

En el presente artículo se analizan las ventajas y desventajas que podría tener la aplicación del principio de oportunidad en el ordenamiento jurídico español, y se fundamenta una posición crítica frente a la aplicación de dicha figura, a partir de la concepción del derecho penal como un conjunto de garantías frente al poder punitivo del Estado.
La crisis de la noción material de bien jurídico en el derecho penal del riesgo
Authors: Jiménez Mejía David
Published: June 2019

Bajo el contexto del Derecho penal del riesgo ha tomado de nuevo fuerza la discusión sobre si los bienes jurídicos son o no el objeto de protección del Derecho penal. Este artículo es una aproximación y toma de postura respecto a una noción material del bien jurídico desde una perspectiva político liberal. El artículo aborda la discusión acerca del alcance y contenido del bien jurídico, el principio de lesividad y el estado actual del concepto del bien jurídico dentro del llamado Derecho penal del riesgo o Derecho penal de la Seguridad.
El tratamiento legal de las técnicas de intervención policial: uso de la fuerza y responsabilidad penal.
Authors: Ruiz Rodríguez Luis Ramón
Published: June 2019

El uso legítimo de la fuerza por parte de los Estados y el instrumento de ejecución que representan las policías carece, generalmente, de una adecuada regulación. Las intervenciones físicas y con armamento por parte de la policía se someten a una serie de principios abstractos insertos en normas muy generales sin la concreción que sería necesaria. Para cubrir estas carencias, los Tribunales de Justicia evalúan el uso de la fuerza policial mediante la eximente de cumplimiento de un deber, pero lo hacen de manera casuística, a partir de principios demasiado abstractos y sin tener en cuenta, en la inmensa mayoría de los casos, la cuestión de la formación recibida, atribuyendo toda la responsabilidad de las actuaciones desmedidas a los sujetos que las desarrollan de forma individual. De ello deriva la necesidad de mejorar la regulación de la intervención operativa policial y de dotar a los tribunales de mejores herramientas jurídicas para resolver los casos más conflictivos.
Los «sufrimientos» del delito de tortura
Authors: Silva Medina Rodrigo
Published: June 2019

El delito de tortura previsto en el Código penal colombiano inicialmente preveía que los sufrimientos físicos o psíquicos que constituyen la parte objetiva del tipo de tortura debían ser graves. En 2005, la Corte Constitucional declaró inexequible la expresión «graves» de dicha definición. No obstante, pueden surgir dudas sobre el sentido de los sufrimientos propios del delito de tortura. ¿Cualquier sufrimiento es susceptible de ser delito de tortura? ¿Hay alguna diferencia entre el sufrimiento del delito de tortura respecto del sufrimiento de otros delitos? En este artículo se propone una interpretación del tipo objetivo del delito de tortura que cumple con el mandato de determinación de la ley penal, es decir, que intenta diferenciar suficientemente la conducta constitutiva de tortura de otras figuras delictivas, para alcanzar la seguridad jurídica en su aplicación.
Aplicación de la ley orgánica reguladora de la responsabilidad penal de los menores a los mayores de 18 años: el discurso en torno a la creación de un DP juvenil
Authors: Trapero Barreales María A.
Published: June 2019

El ideario de la seguridad y el del populismo punitivo han impedido la entrada en vigor del Derecho penal juvenil en España. La propuesta de regulación restrictiva prevista en la ley orgánica reguladora de la responsabilidad penal del menor no ha satisfecho estos planteamientos. Porque en aquella propuesta se podía aplicar la ley penal del menor al joven que cometiera una falta, un delito menos grave sin violencia o intimidación o un delito menos grave sin peligro para las personas. Pero existen fundadas razones para la creación del Derecho penal juvenil, adoptando como criterio rector el de la madurez, extendiendo la regulación de la ley penal del menor a los jóvenes entre 18 a 21 años que se encuentran mentalmente más próximos a la etapa de la adolescencia.
La Ley de los Caballos de 1888: entre la búsqueda del “orden” y la construcción de un enemigo
Authors: Adarve Calle Lina
Published: June 2019

En este artículo se analiza la ineludible relación que existe entre la expedición de las leyes, los motivos para expedirlas y la política estatal y cómo dicha actividad se hace con la intención de instrumentalizar el derecho penal para unos fines determinados.
Las circunstancias de agravación punitiva en el derecho penal colombiano. Aproximaciones a una fundamentación
Authors: Tamayo Patiño Francisco Javier
Published: June 2019

El artículo propone la reflexión sobre el sistema de circunstancias modificativas de responsabilidad en sentido agravado en el derecho penal colombiano. Partiendo de identificar las discusiones doctrinarias sobre su fundamentación y las características de ellas en el sistema positivo colombiano, se hace una propuesta de control de la configuración y aplicación de las circunstancias de agravación desde el contenido material del delito.
Pena de muerte: hacia su abolición global
Authors: De la cuesta José Luis
Published: June 2019

El presente artículo da cuenta de los esfuerzos internacionales por llevar a cabo la abolición de la pena de muerte, desde una reflexión sobre los elementos que pretenden legitimar su imposición y la revisión de los argumentos que persiguen la abolición de la misma.
¿Cuándo una medida es ‘privativa de la libertad’?
Authors: Ceballos Bedoya Juan Sebastián
Published: June 2019

En este texto, el autor pretende ofrecer una aproximación a los criterios que deben tenerse en cuenta para decidir si una medida es privativa de la libertad. De acuerdo con el artículo, para definir cuándo una medida implica privación de la libertad es necesario tener en cuenta dos cuestiones accesorias. Primera, ¿cuál es la libertad afectada por una privación de la libertad? Segunda, ¿cuáles son el sentido y la estructura de esa libertad? Luego de abordar esas cuestiones y de proponer una respuesta a cada una, el texto responde que una medida es privativa de la libertad cuando interfiere superlativamente en las posibilidades individuales de relacionarse con el entorno y con los demás o de no hacerlo.
Consideración sobre las fronteras de la defraudación típica. El problema del fraude de ley en el delito de defraudación tributaria.
Authors: Echavarría Ramírez Ricardo
Published: June 2019

En el texto se analiza el problema de los límites de la conducta penalmente relevante en el delito de defraudación tributaria, concretamente en relación con los comportamientos en fraude de ley. Adicionalmente se analiza la forma se ha enfrentado el problema del fraude de ley, tanto por la doctrina jurídico penal como por parte de la Jurisprudencia del Tribunal Supremo español. Finalmente, se expone y sustenta la tesis de la atipicidad del fraude de ley en el marco del delito de defraudación tributaria.
La conducta punible en el Derecho penal colombiano: Análisis del artículo 9 del Código Penal.
Authors: Sánchez Zapata Sebastián Felipe
Published: June 2019

El artículo 9 del Código Penal colombiano define, como norma rectora del sistema penal, a la conducta punible. El siguiente texto, cuestionando la recepción acrítica de doctrinas
extranjeras al ordenamiento jurídico (y también Códigos, normas, entre otros.), expone algunos de los puntos más trascendentales de la teoría del delito, entre ellos, el concepto de conducta, desvalor de acción y resultado, relación de causalidad e imputación, ubicación sistemática del dolo y el tratamiento penal de los imputables) a través de las interpretaciones de la doctrina penal colombiana.
De los delitos contra los derechos de autor en el Código Penal colombiano.
Authors: Alvarez A. Juan Carlos , Ceballos Bedoya María Adelaida , Muñoz Sierra Álvaro Mauricio
Published: June 2019

Los derechos de propiedad intelectual comprenden los derechos de autor, el derecho de propiedad industrial y el derecho sobre descubrimientos científicos y demás. De allí que en nuestro código penal se encuentren, por un lado, normas protectoras de marcas y patentes (art 306 C.P.); y, por otro, normas relativas a la protección de los derechos de autor (arts. 270 a 272 C.P.). Dentro de estos últimos a su vez se encuentran los derechos de autor en sentido estricto y los derechos conexos o afines: el objeto material en los primeros recae sobre la obra literaria, artística, científica, entre otros.; mientras en los segundos recae sobre la interpretación o ejecución artística de una obra literaria, artística o científica, fonogramas, videogramas y emisiones. La propuesta que aquí se desarrollará es que al momento de interpretar y aplicar estos tipos penales se exija, primero, un ánimo de lucro al autor de la conducta y, segundo, un perjuicio concreto a un tercero. Aceptar esta propuesta no sólo permitirá limitar el tipo penal, sino que también reforzará la protección del elemento patrimonial.
Política global para la protección penal de la propiedad intelectual en la internet.
Authors: Osorio Moreno Cesar Alejandro
Published: June 2019

Las nuevas TICs bajo los principios de la sociedad de la información, nos han llevado a una era digital que demanda respuestas para los nuevos retos en todos los órdenes normativos, y ni la dogmatica jurídico penal ni la política criminal son ajenas a este desarrollo; esta ponencia analizará la afectación de la protección penal de la propiedad intelectual en Internet, en términos de política criminal. Las nuevas tecnologías, y su constante evolución, facilitan una defraudación que se considera masiva de los derechos de propiedad intelectual y que, en sentir de unos, tiene enormes dificultades para la individualización de autores y grandes pérdidas para esta industria, y, en sentir de otros, genera cada vez más normas, incluso de naturaleza extra penal, para tratar de contener los ataques a costa del sacrificio de garantías individuales, identificándose una tendencia clara hacia una política criminal o social de carácter global que pueda hacer frente al fenómeno.