Letteratura scientifica selezionata sul tema "Non linear reactivity"

We reveal the templating effect of substrates with two-fold or three-fold symmetry on the reactivity of acene-based reactants. This allows us to choose whether to form and characterize non-benzenoid conjugated polymers or starphene-derivatives.

Aristolochic acids (AAs) have been used in the treatment of oedema in Chinese herb medicine since long ago. In this paper, molecular electrostatic potential, chemical reactivity and non linear optical properties of aristolochic acid I (AA I) have been analyzed using density functional theory employing 6-311++G(d,p) basis set. The chemical reactivity of the molecule has been explained with the help of chemical reactivity descriptors, molar refractivity and the molecular electrostatic potential surface (ESP). The calculated dipole moment and first order hyperpolarizability show that the molecule possesses non-linear optical property.Journal of Institute of Science and TechnologyVolume 21, Issue 1, August 2016, page: 1-9

The point model of a nuclear reactor with delay in feedback line “power ‐ reactivity” estimating the influence of six groups of delayed neutrons is investigated. A linear and non‐linear analysis of the model is made.

In the series of cephalosporin derivatives, consisting of eight 7-(R1-CH2-CO-NH)cephalosporanic acids and of seven analogical compounds with 3-acetoxymethyl replaced by 3-CH3, physicochemical properties, which are expected to play a role in their antibacterial effects (the transport rate parameters and partition coefficients in the systems 1-octanol-water and 1-octanol-buffer, dissociation constants of the 4-carboxyl group, reactivity towards L-glutathione imitating the nucleophilic groups of the cell components and hydrolysis rate parameters), were determined. Linear dependences were observed between the partition coefficients and the π-constants of the varying substituents as well as between reactivity towards SH-groups of L-glutathione and OH-groups. The relationship between the transport rate parameters and partition coefficients, both measured in buffered as well as non-buffered system, was described by a common non-linear equation.

Indoxyl sulfate (IS), a product metabolized from tryptophan, is negatively correlated with renal function and cardiovascular diseases in patients with chronic kidney disease (CKD). We investigated the association between serum IS levels and endothelial function in patients with CKD. Fasting blood samples were obtained from 110 patients with stages 3–5 CKD. The endothelial function, represented by vascular reactivity index (VRI), was measured non-invasively using digital thermal monitoring. Serum IS levels were determined using liquid chromatography–mass spectrometry. Twenty-one (19.1%), 36 (32.7%), and 53 (48.2%) patients had poor (VRI < 1.0), intermediate (1.0 ≤ VRI < 2.0), and good (VRI ≥ 2.0) vascular reactivity. By univariate linear regression analysis, a higher prevalence of smoking, advanced age, higher systolic, and diastolic blood pressure (DBP), elevated levels of serum phosphorus, blood urea nitrogen, creatinine, and IS were negatively correlated with VRI values, but estimated glomerular filtration rate negatively associated with VRI values. After being adjusted by using multivariate stepwise linear regression analysis, DBP and IS levels were significantly negatively associated with VRI values in CKD patients. We concluded that IS level associated inversely with VRI values and had a modulating role in endothelial function in patients with stages 3–5 CKD.

Recentemente, surgiu na literatura uma solução analítica das equações de cinética pontual que considera a reatividade como função do tempo, utilizando o método da decomposição. O presente trabalho dá um passo a frente, considerando as equações de cinética pontual em conjunto com efeitos de realimentação de temperatura. Mas, primeiro, uma breve introdução do modelo de cinética pontual e dos aspectos relevantes desta abordagem são apresentados. O trabalho prossegue acrescentando a realimentação de temperatura como uma perturbação de primeira ordem na equação reatividade, e através de manipulações algébricas, o conjunto de equações de cinética pontual passa a ser expresso como uma equação diferencial não linear de segunda ordem. Esta equação é, então, resolvida pelo método de decomposição, ou seja, expandindo as variáveis dependentes como séries infinitas, construindo-se então um sistema recursivo que permite calcular cada um dos termo destas séries. A não linearidade é tratada utilizando os polinômios Adomian. Os resultados aqui obtidos são comparados com a literatura, apresentando variações percentuais máximas da ordem de [0,1%]. Faz-se uma breve análise da convergência e da estabilidade da solução, usando um método baseado no critério de Lyapunov.
An analytical solution of the point kinetics equations to calculate reactivity as a function of time by the decomposition method has recently appeared in the literature. The present work goes one step forward, by considering the neutron point kinetics equations together with temperature feedback effects. But first, a brief introduction of the point kinetics model and the relevant aspects of this approach are presented. The work proceeds adding the temperature feedback as a first order perturbation in the reactivity equation, and using algebraic manipulation, the set of point kinetics equations becomes expressed as a non linear second order differential equation. This equation is then solved by the decomposition method, that is, expanding the dependent variables as infinite series, building a recursive system that allows the evaluation of each term of these series. The non linearity is treated using the Adomian polynomials. The results obtained are compared with literature, with maximum percentage changes of about [0,1%]. A brief analysis of the convergence and stability of the solution is made, using a method based on the Lyapunov criterion.

El coneixement de la superfície d'energia potencial (PES) ha estat essencial en el món de la química teòrica per tal de discutir tant la reactivitat química com l'estructura i l'espectroscòpia molecular. En el camp de la reactivitat química es hem proposat continuar amb el desenvolupament de nova metodologia dins el marc de la teoria del funcional de la densitat conceptual. En particular aquesta tesis es centrarà en els següents punts:
a) El nombre i la naturalesa dels seus punts estacionaris del PES poden sofrir canvis radicals modificant el nivell de càlcul utilitzats, de tal manera que per estar segurs de la seva naturalesa cal anar a nivells de càlcul molt elevats. La duresa és una mesura de la resistència d'un sistema químic a canviar la seva configuració electrònica, i segons el principi de màxima duresa on hi hagi un mínim o un màxim d'energia trobarem un màxim o un mínim de duresa, respectivament. A l'escollir tot un conjunt de reaccions problemàtiques des del punt de vista de presència de punts estacionaris erronis, hem observat que els perfils de duresa són més independents de la base i del mètode utilitzats, a més a més sempre presenten el perfil correcte.
b) Hem desenvolupat noves expressions basades en les integracions dels kernels de duresa per tal de determinar la duresa global d'una molècula de manera més precisa que la utilitzada habitualment que està basada en el càlcul numèric de la derivada segona de l'energia respecte al número d'electrons.
c) Hem estudiat la validesa del principis de màxima duresa i de mínima polaritzabiliat en les vibracions asimètriques en sistemes aromàtics. Hem trobat que per aquests sistemes alguns modes vibracionals incompleixen aquests principis i hem analitzat la relació d'aquest l'incompliment amb l'efecte de l'acoblament pseudo-Jahn-Teller. A més a més, hem postulat tot un conjunt de regles molt senzilles que ens permetien deduir si una molècula compliria o no aquests principis sense la realització de cap càlcul previ. Tota aquesta informació ha estat essencial per poder determinar exactament quines són les causes del compliment o l'incompliment del MHP i MPP.
d) Finalment, hem realitzat una expansió de l'energia funcional en termes del nombre d'electrons i de les coordenades normals dintre del conjunt canònic. En la comparació d'aquesta expansió amb l'expansió de l'energia del nombre d'electrons i del potencial extern hem pogut recuperar d'una altra forma diferent tot un conjunt de relacions ja conegudes entre alguns coneguts descriptors de reactivitat del funcional de la densitat i en poden establir tot un conjunt de noves relacions i de nous descriptors.

Dins del marc de les propietats moleculars es proposa generalitzar i millorar la metodologia pel càlcul de la contribució vibracional (Pvib) a les propietats òptiques no lineals (NLO). Tot i que la Pvib no s'ha tingut en compte en la majoria dels estudis teòrics publicats de les propietats NLO, recentment s'ha comprovat que la Pvib de diversos polímers orgànics amb altes propietats òptiques no lineals és fins i tot més gran que la contribució electrònica. Per tant, tenir en compte la Pvib és essencial en el disseny dels nous materials òptics no lineals utilitzats en el camp de la informàtica, les telecomunicacions i la tecnologia làser. Les principals línies d'aquesta tesis sobre aquest tema són:
a) Hem calculat per primera vegada els termes d'alt ordre de Pvib de diversos polímers orgànics amb l'objectiu d'avaluar la seva importància i la convergència de les sèries de Taylor que defineixen aquestes contribucions vibracionals.
b) Hem avaluat les contribucions electròniques i vibracionals per una sèrie de molècules orgàniques representatives utilitzant diferents metodologies, per tal de poder de determinar quina és la manera més senzilla per poder calcular les propietats NLO amb una precisió semiquantitativa.
The knowledge of the potential energy surface (PES) has been essential in the world of the theoretical chemistry to discuss such as the chemistry reactivity as the molecular spectroscopy. In the reactivity chemistry we are interested to develop new methodology in the field of the conceptual functional density theory. This thesis will be center in the following points:
a) The number and character of the different stationary points of the PES can have radical changes modifying the calculation level used. This fact produces that to be sure of the character of a stationary point is necessary to arrive a very precise calculation level. The hardness is a measure of the resistance of a chemistry system to change his electronic configuration, and taking into account the maximum hardness principle, where there is a minimum or a maximum of energy, there also is a minimum or a maximum of hardness, respectively. Choosing a set of problematic reactions in the number of stationary points, we noted that the hardness is more independent of the base and the method used and it always shows the correct shape.
b) We made new expressions based in the integrations of the hardness kernel to predict the global hardness of a molecule in a more precise way that the numerical second derivative of the energy respect to the number of electrons.
c) We studied the validity of the maximum hardness and the minimum polarizability principles in the asymmetric vibrations in aromatic systems. We found that for theses systems some vibrational modes break these principles and we studied the relationship of this non-fulfillment with the pseudo-Jahn-Teller effect. Moreover, we postulated a set of simple rules, that allows deducing if a molecule will follow or not these rules without a previous calculation. All this information has been essential to exactly determine the reasons of the fulfillment or non-fulfillment of the MHP and MPP.
d) Finally, we made an expansion of the functional energy respect to the number of electrons and the normal coordinates into the canonic ensemble. The comparison of this expansion with the expansion of the energy respect to the number of electrons and the external potential give the recuperation of some know relations between traditional reactivity descriptors of DFT, but a different way, and establish a set of new relations and descriptors.
In the field of molecular properties we propose to generalize and improve the methodology to calculate the vibrational contribution (Pvib) to the non-linear optical properties (NLO). Despite of that the Pvib is not taking account into the majority of the theoretical studies published of the properties NLO, it has recently been checked that the Pvib of different organic molecules with high NLO properties is bigger that the electronic contribution. Thus, the Pvib is essential to pattern new NLO materials used in informatics, telecommunications, and laser technology. The main lines of the research about this subject are:
a) We have calculated for the first time the high terms of the Pvib for different organic polymer with the goal to evaluate the importance and the convergence of the Taylor series that define the vibrational contributions.
b) We have evaluated the electronic and vibrational contributions for different representative organic molecules using different methodologies to predict the cheaper way to calculate the NLO properties with semi quantitative precision.

In addition to simple hydrocarbon structures (alkanes, alkenes, alkynes, and aromatic systems) and alkyl groups (methyl, ethyl, propyl, isopropyl, etc.), this text assumes a familiarity with the most common functional groups associated with organic chemical structures and their basic reactivity patterns. Table 1.1 summarizes the names and structures of some of the more important functional groups we will be dealing with throughout the remainder of the book. It is important to remember that functional groups containing O or N with nonbonding electrons have an affinity for both protic and Lewis acids and are important participators in H-bonding. Groups containing a carbonyl (C=O) function are especially important, as these bonds are strongly polarized (δ+C=Oδ–), the C atom being electron deficient and the O atom electron excessive; this strong polarization is mainly responsible for the familiar reactivity patterns associated with carbonyl compounds. Figure 1.1 depicts the standard classification of isomers in organic chemical structures. Recall that constitutional isomers are compounds with the same molecular formula but different atom connectivity, such as 1-butanol versus 2-butanol. Stereoisomers, on the other hand, are compounds with the same formula and the same atom connectivity, differing from one another only in the three-dimensional orientation of their atoms in space. These are divided into two groups: enantiomers and diastereomers. Enantiomers are nonsuperimposable mirror image molecules whose asymmetry is usually the result of a tetrahedral carbon atom with four different atoms or groups attached to it, as in the 2-butanol enantiomers. Such chiral molecules rotate the plane of polarized light either (+) or (−) and so are said to be optically active. Achiral molecules, such as 1-butanol, do not rotate the plane of polarized light and so are optically inactive. A standard formalism for representation of a chiral center is to use bond line drawings with two of the four atoms or groups lying in the plane of the paper, a third projecting outward (wedge bond), and the fourth projecting inward (dashed bond).

Not only has the digital world removed the borders between local and global communication, affording meaning to the already established “glocal” concept, but it has also blurred the boundaries between journalistic and corporate content, revitalising what has traditionally been known in legacy media as “service journalism.” This chapter supposes a continuation of the thought-provoking line of research begun three years ago on journalistic communication and new media, turning to the deconstruction process as a disruptive method to analyze processes, strategies, and trends. If, then, from the perspective of methodology, the focus of attention turns to the structure of the news itself, attending to how new media reactivate the known 5W, and how the conventional news item dies on paper and is ‘resuscitated', transformed into the digital medium, and to how we place ourselves before a transmedia news structure that changes from inverted pyramid to the Rubik's Cube, we now go one step further and put the spotlight on the processes of content building in the digital realm themselves.

Positive identification is the ultimate objective of forensic analysis of blood and other tissue specimens. Nucleotide probes can be very effective tools for detecting genetic markers in this identification process. The genetic markers should be highly polymorphic; allelic variants should be easily and readily detectable; if amplification is required, the alleles should be efficiently amplified using PCR technology; and a statistically sound estimate of the population allele and genotype frequencies should be available. Probes are single-stranded fragments of DNA or RNA containing the complementary code for a specific sequence of genome bases. Probes available for DNA profile analysis will, no doubt, eventually number in the hundreds. Currently, the most valuable detect tandem repetitive sequence fragments either at a specific locus under high-stringency analysis conditions or at numerous loci under low-stringency conditions. Each locus consists of many possible alleles with frequencies that vary depending on the specific population. Other factors also enter into the selection of probes, including ease of amplification, stability, cross-reactivity, and general availability. Rate of allele mutation is also a prime consideration in probe selection. Mutation can be considered at two levels: as the basis for the large number of tandem repeat (VNTR) alleles formed during evolution and as a possible reason for spurious unassignable bands in typing analysis. Although highly unlikely, somatic mutations may be of concern in forensic testing if DNA from different tissues, such as blood and hair roots, are being matched. Germ line (gamete) mutations must be considered when parentage analyses are undertaken. These situations could give rise to false negative results and, therefore, false exclusions. Different considerations also apply for single versus multilocus probes. If a band that is not seen in the putative father is detected in an offspring, the man could incorrectly be excluded if the single-locus probe approach is used. This situation would necessitate testing with more than the usual four or five probes.

Herpes zoster is caused by reactivation of the latent varicella zoster virus (VZV) that causes chicken pox. VZV remains dormant in the dorsal root and cranial ganglia and can reactivate later in a person’s life and cause herpes zoster, which appears predominantly in older adults, but may also occur in those that are immunocompromised. Postherpetic neuralgia (PHN) is defined as pain in the affected dermatome that is still present 1 month after development of the vesicles. Adults older than 50 should receive the herpes zoster vaccine as part of routine medical care. Shingrix is a new vaccine recently approved and recommended by the FDA, which is a non-live, subunit vaccine. In contrast to Zostavax, Shingrix is 97% effective against shingles and 91% effective against PHN for people 50 and older. The diagnosis of herpes zoster can be made on the basis of characteristic skin lesions and pain and itching in the involved dermatome. During the acute phase, an antiviral given within 72 hours of onset helps reduce pain and complications and shorten the course of the disease. The diagnosis of PHN is based on a history of herpes zoster, typical dermatomal distribution of the pain, and hyperalgesia and/or allodynia on physical examination. First-line pharmacotherapy includes gabapentin or pregabalin, tricyclic antidepressants, and SNRIs. Combination therapies are often necessary. Interventional options such as epidural injections, paravertebral blocks, selective nerve root blocks, sympathetic nerve blocks, intercostal nerve blocks, trigeminal nerve blocks, spinal cord or dorsal root ganglion stimulation, and intrathecal therapy may be considered in refractory cases.

BACKGROUND: Daily diary measurements are a common way to assess substance use behaviours, however researchers and clinicians are often cognizant of assessment reactivity (or “reactivity”) in daily substance use measurement. Reactivity involves changes to behaviours that result simply from self-monitoring those behaviours. When reactivity to substance use measurement has been found to exist, it has been identified both as a possible confound in daily diary research and a potential intervention tool in clinical practice. Reactivity to daily self-monitoring of alcohol and tobacco use has been investigated in prior research, however this research has been inconsistent. Reactivity to daily self-monitoring of cannabis use quantity has yet to be documented at all. METHOD: The current study involved secondary analyses of data from N=88 women who self-monitored their cannabis use for 32 consecutive days (Joyce et al., under review). We examined objective reactivity of cannabis use to daily self-monitoring both for the probability of use each day as well as the quantity of cannabis used on each cannabis-using day. At study completion, participants were asked the degree to which they felt self-monitoring impacted their cannabis use (i.e., subjective reactivity). We explored the reported degree of subjective reactivity, and we examined correspondence between objective and subjective reactivity. RESULTS: Hurdle models were the best fit for the data. Participants’ probability of daily cannabis use and the quantity of cannabis use did not change significantly over the study period. For subjective reactivity, many respondents (45%) reported no subjective reactivity, though a majority (55%) reported some degree of subjective reactivity with 24% reporting moderate or more reactivity. A three-step hierarchical linear model was used to investigate the relationship between objective and subjective reactivity. Time was the only predictor in the first step, subjective reactivity was added as a predictor in the second step, and the time x subjective reactivity interaction was explored in the final step. Subjective reactivity was not found to moderate the relationship between time and cannabis use, although there was a significant relationship between self-reported subjective reactivity and variability of cannabis use across the data collection period. CONCLUSIONS: This study determined that participants who report greater subjective reactivity to cannabis measurement are more likely to demonstrate variability in their cannabis usage. While this study did not find a significant change in cannabis scores over time because of reactivity, the non-significant results are valuable from both a research and a clinical standpoint. For research, the lack of change is an indicator that reactivity is likely not a confounding factor in studies involving cannabis daily diary research. From a clinical perspective, the non-significant change indicates that simply self-monitoring cannabis is unlikely to provide standalone benefits when daily self-monitoring is used in clinical practice. It is relevant to note that our study involved a non-help-seeking sample, and future research could benefit from determining whether cannabis reactivity may be moderated by help-seeking behaviours or motivations to change.

The goal of the present work is three fold. Firstly to create the forward continuum model of a multi-species diffusing system under simultaneous presence of chemical reactivity and temperature as the general case of all hydrogen storage systems. Secondly, cast the problem of hydrogen storage in a pragmatic product-design context where the appropriate design parameters of the system are determined via appropriate optimization methods that utilize extensive experimental data encoding the behavior of the system. Thirdly, demonstrate this methodology on characterizing certain systemic parameters. Thus, the context of the work presented is defined by a data-driven characterization of coupled heat and mass diffusion models of hydrogen storage systems from a multiphysics perspective at the macro length scale. In particular, a single wall nanotube (SWNT) based composite is modeled by coupled partial differential equations representing spatio-temporal evolution of distributions of temperature and hydrogen concentration. Analytical solutions of these equations are adopted for an inverse analysis that defines a non-linear optimization problem for determining the parameters of the model by objective function minimization. Experimentally acquired and model produced data are used to construct the system’s objective function. Simulations to demonstrate the applicability of the methodology and a discussion of its potential extension to multi-scale and manufacturing process optimization are also presented.

A New monoclonal antibody, designated as TP85, was produced by fusion of the X63.Ag8.653 murine myeloma cell line with splenocytes from BALB/C mice immunized with washed human platelets. TP85 monoclonal antibody precipitated a single petide of 97,000 daltons in both reduced and nonreduced states by immune precipitation of 125I-labelled solubilized membrane. An isoelectric point was around pH 5.0. The antibody was IgG2b in isotype, as determined by the Ouchterlony immunodiffusion method.The reactivity of TP85 was examined by using indirect immuno-fluorescent assays and ABC immunoperoxidase method. TP85 reacted with platelets, megakaryocytes and erythroblasts from normal human and patients with myeloproliferative disorders, but not with lymphocytes, granulocytes and other bone marrow cells. In a panel of cultured cell line, only 5-10% cells of K652 myeloid/ erythroid cell line were positive, but other cell lines, including common ALL(Reh), T lymphoid(Molt-3, CCRF-CEM), B lymphoid(Raji ,Daudi), myeloid(KG-l, HL-60) and monoblastoid(U937, THP-l) cell lines, were all negative.TP85 did not inhibit platelet aggregations induced by ADP, collagen, epinephrine and ristocetin while TP80 which was an antibody for GPIIb/IIIa inhibited these aggregations except induced by ristocetin.It is concluded that glycoprotein IV, which is immunoprecipitated by TP85, may exist not only on platelet membrane, but also on megakaryocytes and erythroblasts, and has no role on platelet aggregation.

Abstract This paper presents a framework to refine identified artificial neural networks (ANN) based state-space linear parameter-varying (LPV-SS) models with closed-loop data using online transfer learning. An LPV-SS model is assumed to be first identified offline using inputs/outputs data and a model predictive controller (MPC) designed based on this model. Using collected closed-loop batch data, the model is further refined using online transfer learning and thus the control performance is improved. Specifically, fine-tuning, a transfer learning technique, is employed to improve the model. Furthermore, the scenario where the offline identified model and the online controlled system are “similar but not identitical” is discussed. The proposed method is verified by testing on an experimentally validated high-fidelity reactivity controlled compression ignition (RCCI) engine model. The verification results show that the new online transfer learning technique combined with an adaptive MPC law improves the engine control performance to track requested engine loads and desired combustion phasing with minimum errors.

In recent years, market trends towards higher power generation flexibility are driving gas turbine requirements of operation at stable conditions and below environmental emission guarantees over a wide range of operating conditions, such as load, and for changing fuels. In order to achieve these targets, engine components and operation concept need to be optimized to minimise emissions (e.g. CO, NOx) and combustion instabilities, as well as to maximize component lifetime. Therefore the combination of field experience, experimental studies and theoretical modelling of flames with state of the art tools play a key role in enabling the development of such solutions. For many applications the relative changes of reactivity due to changes in operation conditions are important thus in this report a few examples are shown, where chemical kinetics simulations are used to determine the reactivity and to predict engine behaviour. The predicted trends are validated by correlating them to validation data from high pressure test rigs and real gas turbine operational data. With this approach the full operational range from highest reactivity (flashback) to lowest reactivity (blow out or CO emission increase) are covered. The study is focused on the sequential combustor (SEV) of reheat engines and addresses both the safety margins with respect to highly reactive fuels and achievable load flexibility with respect to part load CO emissions. The analysis shows that it is necessary to utilize updated kinetic mechanisms since older schemes have proved to be inaccurate. A version of the mechanism developed at NUI Galway in cooperation with Alstom and Texas A&M was used and the results are encouraging, since they are well in line with experimental test data and can be matched to GT conditions to determine, predict, and optimize their operational range. This example demonstrates nicely how a development over several years starting from fundamental basic research over experimental validation finally delivers a product for power plants. This report therefore validates the kinetic model in combination with the approach to use modelling for guidance of the GT development and extending it fuel capabilities. The GT24 / GT26 can not only be operated with H2 containing fuels, but also at very low part load conditions and with the integration of H2 from electrolysis (∼power to gas ∼PTG) the turndown capability can even be further improved. In this way the energy converted at low electricity prices can be stored and utilised at later times when it is advantageous to run the GT at lower loads increasing the overall flexibility. This development is well suited to integrate renewable energy at highly fluctuating availability and price to the energy provisioning by co-firing with conventional fuels.

Reactivity controlled compression ignition (RCCI) is an advanced low temperature combustion strategy introduced to achieve near-zero NOx and soot emissions while maintaining diesel-like efficiencies. Precise control of RCCI combustion phasing is necessary in realizing high fuel conversion efficiency as well as meeting stringent emission standards. Model-based control of combustion phasing provides a powerful tool for real-time control during transient operation of the RCCI engine, which requires a computationally efficient combustion model that encompasses factors such as, injection timings, fuel blend composition and reactivity. In this work, physics-based models are developed to predict the combustion phasing of a 1.9-liter RCCI engine. A mean value control-oriented model (COM) of RCCI is developed by combining the auto-ignition model, the burn duration model, and a Wiebe function to predict combustion phasing. Development of a model-based controller requires a dynamic model which can predict engine operation, i.e., estimation of combustion phasing, on a cycle-to-cycle basis. Hence, the mean-value model is extended to encompass the full-cycle engine operation by including the expansion and exhaust strokes. In addition, the dynamics stemming from the thermal coupling between cycles are accounted for, that results in a dynamic RCCI control-oriented model capable of predicting the transient operation of the engine. This model is then simplified and linearized in order to develop a linear observer-based feedback controller to control the combustion phasing using the premixed ratio (the ratio of the port injected gasoline fuel to the total gasoline/diesel fuel injected). The designed controller depicts an accurate tracking performance of the desired combustion phasing and successfully rejects external disturbances in engine operating conditions.

The RBMK reactors are channel type, water-cooled and graphite moderated reactors. The first RBMK type electricity production reactor was put on-line in 1973. Currently there are 13 operating reactors of this type. Two of the RBMK-1500 reactors are at the Ignalina NPP in Lithuania. Experimental Critical Facility for RBMK reactors, located at Kurchiatov Institute, Moscow was designed to carry out critical reactivity experiments on assemblies, which imitate parts of the RBMK reactor core. The facility is composed of Control and Protection Rods (CPR’s), fuel assemblies with different enrichment in U-235 and other elements, typical for RBMK reactor core loadings, e.g. additional absorber assemblies, CPR imitators, etc. A simulation of a set of the experiments, performed at the Experimental Critical Facility, was carried out at the Royal Institute of Technology (RIT), Nuclear Power Safety Division, using CORETRAN 3-D neutron dynamics code. The neutron cross sections for assemblies were calculated using HELIOS code. The aim of this work was to evaluate capabilities of the HELIOS code to provide correct cross section data for the RBMK reactor. The calculation results were compared to the similar CORETRAN calculations, when employing WIMS-D4 code generated cross section data. For some of the experiments, where calculation results with CASMO-4 code generated cross sections are available, the comparison is also performed against CASMO-4 results. Eleven different experiments were simulated. Experiments differ in size of the facility core (number of assemblies loaded): from simple core loadings, composed only of a few fuel assemblies, to complicated configurations, which represent a part of the RBMK reactor core. Diverse types of measurements were carried out during these experiments: reactivity, neutron flux distributions (both axial and radial), rod reactivity worth and the voiding effects. Results of the reactivity measurements and relative neutron flux distributions were given in the Experiment report [1] as parameters, to be obtained using static calculations, i.e. the reported results were already processed numerically using the facility equipment, e.g. the reactimeter. The reported measurement errors consist only of instrumentation errors, i.e. measurement method errors and the influence from the space–time effects were not included in the error evaluation.

Platelet aggregation induced by cancer cells may be an essential process in the development of hematogenous metastasis of cancers. A mechanism in HMV-I (human vaginal melanoma cell line)-induced platelet aggregation was studied by using monoclonal antibodies against membrane proteins of cancer cells or platelets. HMV-I cells or their membrana ractions induced platelet aggregation of human heparinized PRP, to which hirudin had no inhibitory effect. The platelet aggregation by HMV-I was completely lost after the pretreatment of the cells with 0.3U/ml neuraminidase for 60 min at 37°C. Preincubation of platelets with monoclonal antibodies against platelet GP lb or GP Ilb/lIIa inhibited HMV-I induced aggregation. A monoclonal antibody MB3 (igM) against another human melanoma (HMMB) which had been transplanted in nude mice was produced by hybridoma technique. Screening studies by cell binding ELISA revealed that MB3 antibody reacted with not only HMMB cells but also many other cells including HMV-I, M7609 (colon carcinoma cell line) and normal fibroblasts. Western-blot analyses showedthat MB3 antibody reacted with multiple, more than ten, proteins with molecular weights ranging from UO to 200 kDa in unreduced SDS-PAGE of HMV-I, HMMB or M7609. In contrast, when .these cells pretreated with neuraminidase were used in Western-blot, MB3 reactivity were all lost. MB3 reacted with at least three glycoproteins of human red cell membrane in Western-blot, but it did not react with human platelets. Immune adherent asgay with trypsin-treated HMV-I or HMMB cells as target cells showed negative reactivity. MB3 antibody inhibited HMV-I-induced aggregation of platelets, but did not inhibit M7609-induced aggregation which depended on thrombin generation.These results suggest that MB3 antibody may be against sialic acid-containing carbohydrate moieties of membrane glycoproteins on these cancercells and that the carbohydrate(s) may play a critical role in' cancer cell-platelet interaction.

Shale-caprock integrity is critical in ensuring that subsurface injection and storage of anthropogenic carbon dioxide (CO2) is permanent. The interaction of clay-rich rock with aqueous CO2 under dynamic conditions requires characterization at the nano-scale due to the low-reactivity of clay minerals. Geochemical mineral-fluid interaction can impact properties of shale rocks primarily through changes in pore geometry/connectivity. Several simulation results had predicted that influx-triggered mineral dissolution/precipitation reactions within clay-rich rock can continuously diminish micro-fracture networks, while pressure and effective-stress evolution initially increase then gradually constrict them. However, most of these studies have not investigated changes under experimental conditions and applying experimental techniques capable of detecting changes at nano-scale, which are ultimately representing pathways for molecular diffusion of fluids through porous media. The experimental work reported in this paper applied specific analytical techniques in investigating changes in surface/near-surface properties of crushed shale rocks after exposure (by flooding) to CO2-brine for a time frame ranging between 30 days to 92 days at elevated pressure and fractional flow rate. Initial capillary entry parameters for the shale were estimated from digitally acquired pressure data evolution. Flooding of the shale samples with CO2-brine was followed by Nano-scale measurement of changes in internal specific surface area, pore volume and linear/cumulative pore size distribution. The BET Technique showed that changes in the shale caprock occurred due to geochemical interaction with aqueous CO2 will impact petrophysical properties of the rock. The intrinsically low permeability in shale may be altered by changes in surface properties as the effective permeability of any porous medium is largely a function of its global pore geometry. Diffusive transport of CO2 as well as carbon accounting could be significantly affected over the long term. The estimation of dimensionless quantities such as Peclet (Pe) and Peclet-Damkohler (PeDa) Numbers that are associated with geochemical reactivity of rocks and acidic fluid transport through porous media gave insight into the impact of diffusion and reaction rate on shale caprock.

Oxidation behavior of dodecane and two mixtures of dodecane and m-xylene (90/10 wt. % and 80/20 wt. %) over an Rh catalyst in a meso-scale heat recirculating combustor was examined to isolate the effect of aromatic content on performance. The fuel conversion, product speciation and reaction kinetics were calculated, and the global combustion behavior observed. The results showed that increasing the amount of m-xylene in the fuel increased the fuel conversion from 85% (pure dodecane) to 92% (90/10) and further to 98% (80/20). The presence of xylene also significantly increased CO2/H2O selectivity and de-creased CO/H2 selectivity. Global activation energy increased linearly with increase in xylene content, supporting that addition of aromatic species to fuel lowers the overall reactivity. The non-catalytic reaction was also simulated using Chemkin software to determine the effect of the Rh catalyst on the combustor performance. The results revealed that the catalyst promotes total oxidation over partial oxidation, and lowers the global activation energy by up to 70%.