RPM Values Research Articles

PERFORMANCE MAP MEASUREMENT, ZERO-DIMENSIONAL MODELLING & VIBRATION ANALYSIS OF A SINGLE CYLINDER DIESEL ENGINE

Single Cylinder Diesel Engines are simple and very economical in manufacturing. Their multipurpose usability and the capability to deliver the maximum power possible within a given envelope makes them very demanding engines in the market. Simulation tools are widely used nowadays to minimize the energy and time needed for a real engine design and development. Zero-dimensional models are very suitable and reliable to observe the engine operation under different conditions. Contrary to the previous studies, this paper presents a comparison between the practical and simulation model data of a single cylinder Diesel Engine. The purpose of this research was to investigate the fundamental variations between the simulation and experimental results with the help of characteristic engine performance maps. Experiments were conducted on a practical 1.16 L Diesel Engine under variable conditions which were then repeated on the simulation model to analyze and evaluate the differences between the obtained results. Zero-dimensional modelling was performed using GT-Power, a powerful commercial engine simulation software. This study also involved the prediction of optimum speed (RPM) of the engine by performing a vibration analysis using a wireless accelerometer. The maximum torque of the 1.16 L Erin Engine is given to be 80 Nm @ 1,800 RPM, while the simulation model indicated it to be 78 Nm at the same RPM value. Likewise, maximum power output was indicated to be 18 kW @ 2,400 RPM, while the experimental results showed it to be 15 kW @ 2,400 RPM. These results laid down a liable basis for the prediction of several operating parameters of the engine which could act as a solid rung for further studies on this subject.

Isomer-Specific Transplacental Transfer of Perfluoroalkyl Acids: Results from a Survey of Paired Maternal, Cord Sera, and Placentas

Currently, information regarding isomer-specific concentrations of PFHxS, PFOS, and PFOA in human placenta, and corresponding placental-maternal ratios (RPM) of these compounds does not exist. The objective of the present study was to assess the occurrence, and distribution of different PFHxS, PFOS, and PFOA isomers in maternal serum, umbilical cord serum, and placenta to gain a better understanding of transplacental transport efficiency and prenatal exposure risks. The study involved quantitative determination of isomer-specific concentrations of PFHxS, PFOS, and PFOA in samples of maternal serum (n = 32), cord serum (n = 32), and placenta (n = 32) from pregnant women in Wuhan, China. The results indicate that both linear and branched PFHxS, PFOS and PFOA can be efficiently transported across the placenta, with exposure levels ordered maternal serum > cord serum > placenta. For PFOS isomers, the concentration ratios between cord serum and maternal serum (RCM) were ordered n < iso < 4m < (3 + 5)m < 1m < ∑m2. The RPM values exhibited a similar trend for branched PFOS isomers: iso < 4m ≈ (3 + 5)m < 1m ≈ ∑m2. Conversely, PFOA isomers did not exhibit an obvious structure-activity relationship for RCM and RPM. n-PFHxS transported across the placenta to a greater extent than br-PFHxS. To the best of our knowledge, this is the first study to report the occurrence of PFHxS, PFOS, and PFOA isomers in human placenta. Further, RPM values of these compounds are reported here for the first time. The findings help to better understand the mechanisms of the placental transfer and neonatal exposure to these important contaminants of concern.

Development of a Soybean Sowing Model Under Laboratory Conditions

Sowing is affected by numerous factors, and thus high‑quality sowing is a very important task for agricultural engineers and managers of profitable agricultural production. The primary purpose of sowing is placing seeds at proper depths and in‑row spacings in well‑prepared soil. Plant population particularly gives prominence to sowing as it directly affects the uniformity of plant growth and development. Soybean planting is especially dependent on the quality of planting for yield formation due to the significant vicinity of seeds. Provided all external factors of high‑quality sowing are met, i.e. sowing conditions, the quality of sowing depends upon the planting mechanism. The following features of the planting mechanism are the most important: RPM of the seed disc, the travel speed of a seeder, and the values of gauge and vacuum pressure. This paper presents the results of sowing three different fractions of soybean seeds under laboratory conditions. The quality measurement of sowing was performed at different values of vacuum pressure and RPM of the seed disc. On balance, an increase in vacuum pressure results in improved sowing quality due to a stronger adherence of seeds to the seed disc. Lower values of vacuum pressure do not exert significant effects on the quality of sowing, regardless of the seed fraction. However, higher RPM of the seed disc entail an increase in the coefficient of variation. On the basis of the results obtained, a mathematical model for predicting changes in the coefficient of variation of sowing quality was developed using different operating parameters.

RNA sequencing for global gene expression associated with muscle growth in a single male modern broiler line compared to a foundational Barred Plymouth Rock chicken line

BackgroundModern broiler chickens exhibit very rapid growth and high feed efficiency compared to unselected chicken breeds. The improved production efficiency in modern broiler chickens was achieved by the intensive genetic selection for meat production. This study was designed to investigate the genetic alterations accumulated in modern broiler breeder lines during selective breeding conducted over several decades.MethodsTo identify genes important in determining muscle growth and feed efficiency in broilers, RNA sequencing (RNAseq) was conducted with breast muscle in modern pedigree male (PeM) broilers (n = 6 per group), and with an unselected foundation broiler line (Barred Plymouth Rock; BPR). The RNAseq analysis was carried out using Ilumina Hiseq (2 x 100 bp paired end read) and raw reads were assembled with the galgal4 reference chicken genome. With normalized RPM values, genes showing >10 average read counts were chosen and genes showing <0.05 p-value and >1.3 fold change were considered as differentially expressed (DE) between PeM and BPR. DE genes were subjected to Ingenuity Pathway Analysis (IPA) for bioinformatic functional interpretation.ResultsThe results indicate that 2,464 DE genes were identified in the comparison between PeM and BPR. Interestingly, the expression of genes encoding mitochondrial proteins in chicken are significantly biased towards the BPR group, suggesting a lowered mitochondrial content in PeM chicken muscles compared to BPR chicken. This result is inconsistent with more slow muscle fibers bearing a lower mitochondrial content in the PeM. The molecular, cellular and physiological functions of DE genes in the comparison between PeM and BPR include organismal injury, carbohydrate metabolism, cell growth/proliferation, and skeletal muscle system development, indicating that cellular mechanisms in modern broiler lines are tightly associated with rapid growth and differential muscle fiber contents compared to the unselected BPR line. Particularly, PDGF (platelet derived growth factor) signaling and NFE2L2 (nuclear factor, erythroid 2-like 2; also known as NRF2) mediated oxidative stress response pathways appear to be activated in modern broiler compared to the foundational BPR line. Upstream and network analyses revealed that the MSTN (myostatin) –FST (follistatin) interactions and inhibition of AR (androgen receptor) were predicted to be effective regulatory factors for DE genes in modern broiler line. PRKAG3 (protein kinase, AMP-activated, gamma 3 non-catalytic subunit) and LIPE (lipase E) are predicted as core regulatory factors for myogenic development, nutrient and lipid metabolism.ConclusionThe highly upregulated genes in PeM may represent phenotypes of subclinical myopathy commonly observed in the commercial broiler breast tissue, that can lead to muscle hardening, named as woody breast. By investigating global gene expression in a highly selected pedigree broiler line and a foundational breed (Barred Plymouth Rock), the results provide insight into cellular mechanisms that regulate muscle growth, fiber composition and feed efficiency.

Effect of drilling fluid hydraulics on drill stem vibrations

Drill stem vibration may cause drilling inefficiencies and often leads to non-productive time. Drill stem vibration analysis is performed to prevent and identify RPM values that may cause damaging standing waves in the drill stem. However, different models and assumptions give different vibration results. One simplification commonly done is excluding drilling fluids. This paper investigates the effect of including drilling hydraulics and the dynamic pressure on drill stem vibrations. The model assumes the drill stem is acting as a Euler Bernoulli beam and was discretized using a finite element formulation. Two fluid rheological models, Herschel Bulkley and Power Law, were used to determine the uncoupled dynamic pressure drop across the drill stem. The results show that including the dynamic pressure in the drill stem vibration model causes the critical rotational speeds to change as much as 32% (i.e. 59 RPM). As expected, axial and torsional vibrations are not affected, while lateral vibration changes significantly when the ratio of the wellbore diameter to the drill stem outside diameter is below 1.25, with a narrow total drill bit flow area, or when operating at high flow rates. Therefore, when creating RPM road maps to avoid vibrations while drilling, the contribution of the dynamic pressure should be included.

Multi-objective optimization of a natural aspirated three-cylinder spark ignition engine using modified non-dominated sorting genetic algorithm and multicriteria decision making

The main purpose of this study is to find a special set of filling and emptying parameters of a three-cylinder engine, including geometrical design of intake manifold, intake and exhaust valve timing as design variables of the multi-objective optimization problem, which lead to the best values of BSFC (Brake Specific Fuel Consumption), and torque of the engine at all working speeds as four separate objective functions. The modified Non-dominated Sorting Genetic Algorithm (NSGA-II), which is an evolutionary Pareto-based method, is used as the optimization algorithm, and the technique for order of preference by similarity to ideal solution is used as a Multi-Criteria Decision Making Method to select the trade-off design based on different design strategies through the design vectors which are proposed. Group Method of Data Handling-type of Artificial Neural Networks is used to predict the relation between the design variables and the objective functions based on a 243-sized set of samples, which are chosen by Factorial method, and the corresponding engine designs are simulated using GT-SUITE as an Engine Simulation Software. The method of simulation is verified by comparison of experiment and simulation results. The verification process shows that the engine simulation code could predict the engine's performance by 4.78% error. Convergence and start point independence of the optimization algorithm (modified NSGA-II) is also investigated. The final results show remarkable improvement in BSFC and torque at 3500 RPM and mean value of BSFC at all working speeds along with a small reduction in mean value of the engine's torque at all working speeds compared to corresponding characteristics of a similar three-cylinder engine.

Critical phenomena in {bromobenzene + 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide} binary solution

The liquid-liquid coexistence curve for binary solution {bromobenzene + 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C6mim][NTf2])} has been measured in both critical and non-critical regions. The isobaric heat capacities per unit volume were measured in one-phase and two-phase regions. Moreover, the turbidity measurements were also performed in the near-critical one-phase region. From the liquid-liquid equilibrium, heat capacity and turbidity data collected in the critical region, the critical exponents α, β, γ and ν were obtained and shown to be consistent with those predicted for the 3D-Ising universality class. The universal critical amplitude ratios RB and X have been calculated and shown to reasonably coincide with the theoretical predicted values. The asymmetric behavior of the diameter of the coexistence curve was well described by the complete scaling theory, provided that the heat capacity related term was considered. Moreover, the coulombic criticality of the studied system was indicated by the small values of RPM reduced critical density and critical temperature.

Evaluation of a cost-effective and energy-efficient disc material for rotating biological contactors (RBC), and performance evaluation under varying condition of RPM and submergence

This study was carried out to evaluate the suitability of polyethylene foam as disc material for rotating biological contactors (RBC). Effect on DO levels due to change in RPM and submergence was also investigated. For this purpose, a pilot-scale model of RBC was constructed. The model was operated at 3, 5 and 7 RPM with varying submergence of discs, i.e. 30, 40, 50, 60 and 70%. Domestic sewage was used to run the model. Different parameters like pH, DO, total suspended solids (TSS), BOD and COD were monitored for the influent and effluent of pilot-scale RBC under varying operating conditions. Optimum values of submergence and RPM were found to be 40% and 5 RPM, respectively. BOD and COD removal, under optimum conditions, were 85.7 and 67.6%, respectively. The effluent concentrations for BOD and COD, under optimum conditions, were 42 and 124 mg/L, respectively, meeting the national effluent standards, with DO level of 4.6 mg/L. New disc material used costs US$ 0.38, while conventionally used material, i.e. polystyrene costs US$ 1.91 per square metre. Due to lesser weight energy consumption of newly proposed material is 26 kWh/m3/year while for Polystyrene it is 96.6 kWh/m3/year, no wear and tear of material was found after a continuous run of 90 d. Analysis of variance showed that submergence has more dominant role in raising DO levels as compared to RPM.

Flow-pattern switching in a motored spark ignition engine

Cycle-to-cycle variability of intake-jet flow in an optical engine was measured using particle image velocimetry, revealing the possibility of two different flow patterns. A phase-dependent proper orthogonal decomposition analysis showed that one or the other flow pattern would appear in the average flow, sampled from test to test or sub-sampled within a single test; each data set contained individual cycles showing one flow pattern or the other. Three-dimensional velocity data from a large-eddy simulation of the engine showed that the particle image velocimetry plane cuts through a region of high shear between the intake jet and another large flow structure. Rotating the measurement plane ±10° revealed one or the other flow structure observed in the particle image velocimetry measurements. Thus, it was hypothesized that cycle-to-cycle variations in the swirl ratio result in the two different flow patterns in the particle image velocimetry plane. Having an unambiguous metric to reveal large-scale flow cycle-to-cycle variability, causes for this variability were examined within the possible sources present in the available testing. In particular, variations in intake-port and cylinder pressure, lateral valve oscillations, and engine RPM were examined as potential causes for the cycle-to-cycle flow variations using the phase-dependent proper orthogonal decomposition coefficients. No direct correlation was seen between the intake-port pressure, or the pressure drop across the intake valve, and the in-cylinder flow pattern. A correlation was observed between dominant flow pattern and cycle-to-cycle variations in intake-valve horizontal position. RPM values and in-cylinder flow patterns did not correlate directly. However, a shift in flow pattern was observed between early and late cycles in a 2900-cycle test after an approximately 5 r/min engine speed perturbation.

Venous cannula performance assessment in a realistic caval tree model.

A new caval tree system was designed for realistic in vitro simulation. The objective of our study was to assess cannula performance for virtually wall-less versus standard percutaneous thin-walled venous cannulas in a setting of venous collapse in case of negative pressure. For a collapsible caval model, a very flexible plastic material was selected, and a model with nine afferent veins was designed according to the anatomy of the vena cava. A flow bench was built including a lower reservoir holding the caval tree, built by taking into account the main afferent vessels and their flow provided by a reservoir 6 cm above. A cannula was inserted in this caval tree and connected to a centrifugal pump that, in turn, was connected to a reservoir positioned 83 cm above the second lower reservoir (after-load = 60 mmHg). Using the same pre-load, the simulated venous drainage for cardiopulmonary bypass was realized using a 24 F wall-less cannula (Smartcanula) and 25 F percutaneous cannula (Biomedicus), and stepwise increased augmentation (1500 RPM, 2000 and 2500 RPM) of venous drainage. For the thin wall and the wall-less cannulas, 36 pairs of flow and pressure measurements were realized for three different RPM values. The mean Q-values at 1500, 2000 and 2500 RPM were: 3.98 ± 0.01, 6.27 ± 0.02 and 9.81 ± 0.02 l/min for the wall-less cannula (P <0.0001), versus 2.74 ± 0.02, 3.06 ± 0.05, 6.78 ± 0.02 l/min for the thin-wall cannula (P <0.0001). The corresponding inlet pressure values were: -8.88 ± 0.01, -23.69 ± 0.81 and -70.22 ± 0.18 mmHg for the wall-less cannula (P <0.0001), versus -36.69 ± 1.88, -80.85 ± 1.71 and -101.83 ± 0.45 mmHg for the thin-wall cannula (P <0.0001). The thin-wall cannula showed mean Q-values 37% less and mean P values 26% more when compared with the wall-less cannula (P <0.0001). Our in vitro water test was able to mimic a negative pressure situation, where the wall-less cannula design performs better compared with the traditional thin-wall cannula.

Discovery Of Genome Wide Epigenetic Programming In t(4;14) Multiple Myeloma and In The Progression From Myeloma To Plasma Cell Leukemia Via Methyl Binding Domain Protein Capture and Sequencing

BackgroundThe t(4;14) translocation in multiple myeloma is associated with aggressive disease behavior and shorter survival despite recent advances in therapy. The histone methyltransferase MMSET/WHSC1 is overexpressed as a consequence of the translocation, but the detailed epigenetic downstream effects of this overexpression are unknown. Our group identified a specific DNA hypermethylation pattern in t(4;14) cases, indicating a strong contribution of epigenetic changes to the aggressive biology of this subtype. We have here performed genome wide methyl-binding domain protein capture and next generation sequencing (MBD-seq) to characterize the epigenetic perturbations in t(4;14) myeloma in contrast to t(11;14) cases, a subgroup with favorable clinical behavior. Patient bone marrow myeloma cells at presentation and at progression to plasma cell leukemia were analysed to identify epigenetic mechanisms characteristic for early and late stage disease. MethodsMBD-seq data were generated from bone marrow myeloma samples of 3 t(4;14) and 3 t(11;14) cases at both presentation and plasma cell leukemia (PCL) stages. Data were analyzed with the MEDIPS package and RPM values for 500 bp bins were calculated. Due to copy number sensitivity of the method, matched Affymetrix SNP genotyping array data were used to correct for focal genomic gains and losses. Pairwise contrasts were calculated and results were filtered for statistical significance (p<0.01) and RPM value differences (>20) to generate lists of differentially methylated regions (DMRs). Publicly available ENCODE datasets such as chromatin state segmentation for the B-lymphocytic GM12878 cell line were used to identify epigenetic mechanisms involved in MMSET activity and disease progression. Matched gene expression data have been generated for presentation myeloma cases and exome sequencing has been performed for a t(4;14) and a t(11;14) myeloma case. ResultsCopy number corrected MBD-seq results confirmed the previous observation of a specific DNA hypermethylation pattern in t(4;14) versus t(11;14) cases (2729 hyper vs. 582 hypomethylated DMRs). Comparison of t(4;14) specific DMRs with publicly available datasets (GREAT, Bejerano Lab, Stanford) revealed genome wide significant overlap with the top 50 overexpressed genes of the “MS” cluster consisting of t(4;14) cases (binomial FDR q-value: 1.28e-9), confirming the functional epigenetic involvement in t(4;14) biology. There was also significant overlap with the module Genes in the AKT1 Pathway (q-value: 6.62e-8). Comparison of results with ENCODE Chromatin states data for B lymphocytes (GM12878) demonstrated significant overrepresentation of “weak enhancer” and “weak promoter” regions in t(4;14) hypermethylated DMRs. In contrast, hypomethylated DMRs in t(4;14) were significantly enriched for “transcriptional transition” and “transcriptional elongation” (MCFDR p-value=0.0 for both), with overrepresentation of histone marks H3K20me1 and H3K36me3 in GM12878. Hypomethylated regions mapped to MUM1/IRF4 and to several epigenetic modifiers such as CTCF, highlighting a functionally important, specific set of hypomethylated genes in t(4;14).Progression to PCL was accompanied by significant preferential hypermethylation of regulatory enhancers and promoter regions and of the “polycomb group repressed” chromatin state both in t(4;14) and t(11;14) groups. Hypomethylation occurred in regions of “heterochromatin” state in t(4;14) MM to PCL progression and significantly more than expected in repetitive regions accompanying t(11;14) progression. Comparing t(4;14) and t(11;14) PCL demonstrated significant t(4;14) hypermethylation of regulatory regions (enhancers, promoters) and significant relative preferential t(4;14) hypomethylation of the “transcriptional elongation” chromatin state, indicating some maintained functional epigenetic programming by MMSET in t(4;14) PCL. ConclusionWe have characterized the genome wide epigenetic programming of DNA methylation in MMSET overexpressing t(4;14) myeloma and PCL identifying key regulatory pathways involved in t(4;14) biology. We have also identified focal regulatory sequences, enhancers and promoters, which are affected specifically in the t(4;14) which may be linked to the biology of the this disease subtype. Disclosures:No relevant conflicts of interest to declare.

The effect of the propeller jet on pile groups

The objective of this study is to determine the effect of jet propeller on the damage of berthing structures combined of armoured slope with pile groups. For this purpose, scour measurements were performed for four types berthing structures, which were armoured slope with tandem arrangements of piles for two and three piles and with side by side arrangements of piles for two and three piles. The effect of gap between piles on damage was investigated. The damage level induced by propeller jet between piles was determined. The gaps were 1, 2, 3, and 4 times the pile diameter. Three different values of R pm (690, 820, and 950) were chosen for the tests. The diameter of circular piles is 40 mm. The slope ratio was 1/3 and the diameter of propeller was 10 cm.

Effect of turbine section orientation on the performance characteristics of an oscillating water column device

Oscillating water column (OWC) devices are the most successful devices for extracting energy from ocean waves. In oscillating water column devices, the air turbine section is of either horizontal or vertical orientation. An experimental study is carried out to compare the airflow characteristics and turbine rpm in horizontal and vertical turbine sections of an oscillating water column device. Two OWC models, one with a horizontal duct connecting the turbine to the atmosphere and the other with a vertical duct, were tested at mean water depths of 230mm, 260mm and 290mm and at frequencies of 0.6Hz, 0.7Hz, 0.8Hz, 0.9Hz, 1.0Hz and 1.1Hz. Mean total pressure profiles were plotted just upstream and downstream of the turbine section for different cases, while instantaneous static and dynamic pressure measurements were performed to study their variations with time at these locations. A Savonius type rotor was used as a turbine and its rpm was measured and at the above depths and frequencies to compare the performance of the two OWC models. The OWC model with the horizontal turbine section showed better performance characteristics compared to the OWC with the vertical turbine section. RPM values were 20–30% greater in the horizontal turbine orientation compared to the vertical one. The successful use of a Savonius type rotor as a good and cost-effective option for energy conversion is emphasized in this work.

Improved Drilling Efficiency Technique Using Integrated PDM and PDC Bit Parameters

Summary In this paper, a new drilling optimization procedure is presented that is designed to improve the drilling efficiency with positive displacement motors (PDMs) and PDC bits. This developed optimization method is based on predicting rate of penetration (ROP) from PDM outputs for any PDC bit design. More specifically, optimization is done for a hole section and optimum values of weight on bit (WOB) and surface RPM are obtained for the section. For given flow rates, estimated values of optimum WOB and surface RPM are used to calculate the corresponding motor differential pressures and the foot by foot ROP values. Also, the method is used to show how improper operational parameter selection can affect total drilling time. A case study was done to consider different PDMs with different lobe configurations and a set of fixed operational parameters. The presented method is verified by generating a confined rock strength log based on drilling data for a previously drilled well in Alberta. This foot-by-foot strength log is compared to a confined rock strength log generated as a follow-up analysis by a commercially available drilling simulator package. Also, a PDM differential pressure log is generated and compared to field-recorded on-bottom differential pressure values. The method's application is best demonstrated by simulating the drilling operation of the Alberta well with three different PDMs. It is shown that consideration of PDM performance/selection in the drilling planning phase will help to perform a safe and cost-effective operation by preventing motor stalls and maintaining highest average ROP for the section. It is also shown that by optimizing WOB and surface RPM values for a constant mud flow rate and predefined bit wear at total depth, a maximum average ROP for the section can be reached for any PDM.

A New Resource-Constrained Triage Method Applied to Victims of Penetrating Injury

Resource-constrained triage occurs when the number of trauma patients exceeds the capacity for simultaneous transport and treatment. The objective of this article is to apply a new resource-constrained triage method (denoted Sacco triage method [STM]) to victims of penetrating trauma and compare it with existing methods. STM is a mathematical model of resource-constrained triage. Its objective is to maximize expected survivors given constraints on the timing and availability of resources. The model incorporates estimates of time-dependent victim survival probabilities based on initial assessments and expected deteriorations. For application to penetrating trauma, an "RPM" score based on respiratory rate, pulse rate, and best motor response was used to predict survivability. Logistic function-generated survival probability estimates for scene values of RPM were determined from 7,274 penetrating injury patients from the Pennsylvania Trauma Outcome Study. The Delphi Method provided expert consensus on victim deterioration rates, and the model was solved using linear programming. The accuracy of predicting survivability was assessed using calibration and discrimination statistics. STM was compared with START (Simple Triage and Rapid Treatment)-like triage methods with respect to process and outcomes (assessed by expected number of survivors in simulated resource-constrained casualty incidents). RPM was shown to be an accurate predictor of survival probability for penetrating trauma, equivalent to the Revised Trauma Score and exceeding that of the Injury Severity Score, as measured by calibration and discrimination statistics. In the simulations, STM had substantially more expected survivors than did current triage methods. Resource-constrained triage is modeled as an evidence-based, outcome-driven method (STM) that maximizes expected survivors in consideration of resources. STM offers lifesaving and operational advantages over current methods.

Whither Latin America? trends and challenges of science in Latin America

Science in Latin America has experienced vigorous growth in the past decade, as demonstrated by the fact that the Latin American share of the world's scientific publications increased from 1.8% in 1991-1995 to 3.4% in 1999-2003. Significant growth has also taken place in the numbers of PhDs in science and engineering (S&E) awarded in Latin American countries in recent years, including those in the natural sciences. Importantly, albeit at different rates, growth has been verified in almost all countries in the region, indicating a general effort to promote the development of S&E. In most research fields, however, the recognition or relative impact of Latin American science, as measured by the average number of citations received by published articles (CpP), is still below world averages and much lower than in developed nations. We show that average CpP values for a set of 34 representative developing and developed countries correlate significantly with gross expenditure in research and development (GERD), with gross domestic product (GDP) per capita and with the number of researchers per million inhabitants (RpM). Among those countries, Latin American nations present some of the lowest average values of CpP (<6), GERD (< or =1% of GDP) and RpM (<2,000). We also examined recent trends in scientific activity in Latin America, with focus on the natural sciences and on biochemistry and molecular biology (BMB). In terms of citation scores, publications in BMB compare favorably to those in other research fields within Latin America. At the same time, however, Latin American BMB is one of the areas for which relative impact--compared to developed nations or normalized to world averages--is lowest. These observations clearly indicate the need to establish effective policies to increase competitiveness in terms of the quality and international recognition of Latin American natural sciences in general, and BMB in particular, as opposed to merely increasing the absolute numbers of publications or the numbers of PhDs awarded in the region.

Precise Formulation and Evidence‐based Application of Resource‐constrained Triage

To develop a precise mathematical formulation of resource-constrained triage, denoted the Sacco triage method (STM), to develop an evidence-based application to blunt trauma, and to compare the STM with the simple triage and rapid treatment (START) method. Resource-constrained triage is modeled mathematically as a classic resource allocation problem. The objective is to maximize expected survivors given constraints on the timing and availability of resources. The model incorporates estimates of time-dependent victim survival probabilities based on an initial assessment and expected deterioration. For application to blunt trauma, an "RPM" score, based on respiratory rate, pulse rate, and motor response, was used to predict survivability. Logistic function-generated survival probability estimates for scene values of RPM were determined from 76,459 blunt-injured patients from the Pennsylvania Trauma Outcome Study (PTOS). The Delphi method provided expert consensus on victim deterioration rates, and the model was solved using linear programming. STM was compared with START across various criteria of process and outcome. Outcome was measured by expected number of survivors in simulated resource-constrained casualty incidents. In this mathematical simulation, RPM was a more accurate predictor of survivability from blunt trauma than the Injury Severity Score and the Revised Trauma Score, as measured by calibration and discrimination statistics. STM resulted in greater expected survivorship than START in all simulations. Resource-constrained triage is modeled precisely as an evidence-based, outcome-driven method that maximizes expected survivors in consideration of resources. The lifesaving potential and operational advantages over current methods warrant scrutiny and further research.

EXTRUDED CORN GRITS?QUINOA BLENDS: II. PHYSICAL CHARACTERISTICS of EXTRUDED PRODUCTS

Quinoa was blended with corn grits at levels of 10%, 20% and 30% and extruded at 15% and 25% moisture respectively, using screws with a 1:1 or 3:1 compression ratio. Extrusion temperatures were 80° and 100°C at the feed section and 100° or 150°C at the compression section, respectively. RPM values were 100, 150 and 200. Quinoa addition produced a darker, less yellow product than corn grits alone. Density, expansion ratio and shear strength were lower for products containing greater levels of quinoa. the most favorable products were produced at a 15% initial moisture content and a 3:1 compression ratio. Products extruded under these conditions had the greater expansion, lower density and lower shear strength than products extruded at 25% moisture or at a 1:1 compression ratio. SEM showed larger, more uniform cells in the 100% corn grits product indicating a more even expansion. A product containing 30% quinoa had a rougher texture, many broken cell walls and less evenly distributed air cells.

Solvent effect on electrochemical polymerization of aromatic compounds

The effects of the electrolytic conditions on the outcome of the electrochemical polymerization of pyrrole, thiophene and benzene were investigated. The solvent nucleophilicity, represented by the donor number, was found to affect the selectivity of the film formation. These solvent effects were explained in terms of the radical cation character of the intermediate and were quite similar to that of cationic polymerization of vinyl monomers. The solvent polarity, defined by the RPM value, was related to the current density during the reaction.

Characteristics of Propeller Noise on an Aircraft Fuselage

Exterior noise was measured on the fuselage of a twin-engine, light aircraft at four values of engine rpm in ground static tests and at forward speeds up to 36 m/s in taxi tests. Propeller noise levels, spectra, and correlations were determined using a horizontal array of seven flush-mounted microphones and a vertical array of four flush-mounted microphones in the propeller plane. The measured levels and spectra are compared with predictions based on empirical and analytical methods for static and taxi conditions. Trace velocities obtained from point-to-point correlations are used to describe the propagating and rotating characteristics of the propeller noise field on the fuselage.