Thixotropy and structural breakdown properties of self consolidating concrete containing various supplementary cementitious materials

In this study, thixotropy and structural breakdown of 57 self-consolidating concrete (SCC) mixtures containing various supplementary cementitious materials (SCM) were investigated by different approaches. The effects of SCM type and content on high range water reducer demand and plastic viscosity were also studied. For these purposes, various amounts of silica fume (SF), metakaolin (MK), Class F fly ash (FAF), Class C fly ash (FAC) and granulated blast-furnace slag (BFS) were utilized in binary, ternary, and quaternary cementitious blends in three water/binder (w/b) ratios. Results showed that except BFS, use of SCM in SCC mixtures increased thixotropy values in comparison with the mixtures containing only portland cement (PC). Good correlations were established between structural breakdown area and drop in apparent viscosity values for all w/b ratios. The different methods used to evaluate the thixotropy and structural breakdown got more consistent with each other as w/b decreased.     

Constructing a multi-objective measure of research performance

This paper focuses on the dichotomy between the multifaceted and multidimensional nature of contemporary R&D activity and unidimensional approaches to the measurement of its performance. While publications in refereed journals and citations are the most preferred indicators of research performance, there are also other indicators such as chapters in edited books, research reports, patents, algorithms, prototypes and designs, etc., which cannot be overlooked. Even when multiple indicators are used, they are used in isolation with the result that one gets only partial views of a multidimensional manifold. Here, a major problem is how to construct a composite measure of research performance, without assigning arbitrary weights to different measures of research output. This problem is particularly important for cross-institutional and cross-national comparisons of research performance. In this paper we have demonstrated the feasibility of constructing a multi-objective measure of research performance using Partial Order Scoring (POSCOR) algorithm developed by Hunya (1976). The algorithm is briefly described and applied to the empirical data on research outputs of 1460 research units in different socio-cultural, institutional and disciplinary settings. The potentialities and limitations of using POSCOR algorithm in scientometric analysis are briefly discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

某远程多管火箭振动特性研究

建立了某远程多管火箭动力学模型,从理论、计算、试验三方面对远程多管火箭的振动特性进行研究。用 多体系统传递矩阵法,计算了刚弹耦合远程多管火箭多体系统固有振动特性。进行了模态试验,计算结果与模态试验结 果吻合较好。     

Both pelvic radiography and lateral abdominal radiography correlate well with coronary artery calcification measured by computed tomography in hemodialysis patients: A cross‐sectional study

Introduction Lateral abdominal radiograph is suggested as an alternative to coronary artery computed tomography (CT) in evaluating vascular calcification. Simple scoring systems including pelvic radiograph scoring and abdominal scoring system were utilized to study their correlation with coronary artery calcification. Methods In 106 MHD patients, coronary artery CT, lateral abdominal, and pelvic radiograph were taken. The Agatston scoring system was applied to evaluate the degree of coronary artery calcification which was categorized according to Agatston coronary artery calcification score (CACS) ≥ 30, ≥100, ≥400, and ≥1000. Abdominal aortic calcification was scored by 4‐scored and 24‐scored systems. Pelvic artery calcification was scored by a 4‐scored system. Sensitivities and specificities of abdominal aortic calcification scores and pelvic artery calcification scores to predict different categories of coronary artery calcification were analyzed. We studied the diagnostic capability of abdominal aorta calcification and pelvic artery calcification to predict different CACS categories by calculating likelihood ratios. Receiver operator characteristic curves were used to determine the area under the curve for each of these testing procedures. Findings The prevalence was 48(45.3%), 15 (14.2%), 11 (10.4%), 11 (10.4%), and 11 (10.4%) for CACs > 0, ≥30, ≥100, ≥400, and ≥1000, respectively. The degree of CACs was positively correlated with patient age, prevalence of diabetes, abdominal aorta scores, and pelvic calcification scores. The areas under the curves for different CACS by all X‐ray scoring systems were above 0.70 except pelvic 4‐scored system for diagnosing CACS ≥30, without significant difference (P > 0.05). Discussion Both lateral abdominal and pelvic plain radiographs were demonstrated as acceptable alternatives to CT in evaluating vascular calcification.     

Mass-specific scattering coefficient for natural minerogenic particle populations: particle size distribution effect and closure analyses

The relationship between the particulate scattering coefficient (b(p)) and the concentration of suspended particulate matter (SPM), as represented by the mass-specific scattering coefficient of particulates (b(p)*=b(p)/SPM), depends on particle size distribution (PSD). This dependence is quantified for minerogenic particle populations in this paper through calculations of b(p)* for common minerals as idealized populations (monodispersed spheres); contemporaneous measurements of b(p), SPM, and light-scattering attributes of mineral particles with scanning electron microscopy interfaced with automated image and x-ray analyses (SAX), for a connected stream-reservoir system where minerogenic particles dominate b(p); and estimates of b(p) and its size dependency (through SAX results-driven Mie theory calculations), particle volume concentration, and b(p)*. Modest changes in minerogenic PSDs are shown to result in substantial variations in b(p)*. Good closure of the SAX-based estimates of b(p) and particle volume concentration with bulk measurements is demonstrated. Converging relationships between b(p)* and particle size, developed from three approaches, were well described by power law expressions.     

Ocean inherent optical property estimation from irradiances

A method is evaluated for estimating the absorption coefficient a and the backscattering coefficient b(b) from measurements of the upward and downward irradiances E(u)(z) and E(d)(z). With this method, the reflectance ratio R(z) and the downward diffuse attenuation coefficient K(d)(z) obtained from E(u)(z) and E(d)(z) are used to estimate the inherent optical properties R(infinity) and K(infinity) that are the asymptotic values of R(z) and K(d)(z), respectively. For an assumed scattering phase function beta , there are unique correlations between the values of R(infinity) and K(infinity) and those of a and b(b) that can be derived from the radiative transfer equation. Good estimates of a and the Gordon parameter G = b(b)/(a + b(b)) can be obtained from R(infinity) and K(infinity) if the true scattering phase function is not greatly different from the assumed function. The method works best in deep, homogeneous waters, but can be applied to some cases of stratified waters. To improve performance in shallow waters where bottom effects are important, the deep- and shallow-measurement reflectance models also are developed.     

Scanning electrochemical microscopy. 41. Theory and characterization of ring electrodes

Ring ultramicroelectrodes, which are of particular interest as probes for scanning electrochemical microscopy (SECM), combined with near-field scanning optical microscopy, were investigated. Theoretical SECM tip current-distance (approach) curves for a ring electrode were calculated by numerical (finite element) analysis. The SECM curves obtained were a function of the geometry of the tips including the thickness of the ring and the insulating sheath. Theoretical approach curves over conductive substrates showed a strong dependence on the ratio of inner to outer radii of ring microelectrodes (a/b) and were relatively insensitive to the thickness of the insulating sheath (r(g)). For insulating substrates, however, the approach curves varied significantly with r(g), but much less with the a/b ratio. Comparison of experimental and theoretical SECM curves provided a good method of evaluating the size and shape of ring electrodes. Good agreement of the experimental and theoretical curves was found with a ring microelectrode with a nominal 200-nm ring thickness, yielding values of 1.7, 1.9, and 5.7 microm for the inner (a) and outer (b) radii of a ring and the outermost radius of insulating sheath (r(g)), respectively.     

Effective algorithms for parametrizing linear control systems over Ore algebras

In this paper, we study linear control systems over Ore algebras. Within this mathematical framework, we can simultaneously deal with different classes of linear control systems such as time-varying systems of ordinary differential equations (ODEs), differential time-delay systems, underdetermined systems of partial differential equations (PDEs), multidimensional discrete systems, multidimensional convolutional codes, etc. We give effective algorithms which check whether or not a linear control system over some Ore algebra is controllable, parametrizable, flat or π-free. This paper is dedicated to the memory of our dear friend and colleague Manuel Bronstein. The third author has been financially supported by the Control Training Site grant HPMT-CT-2001-00278 and the Deutsche Forschungsgemeinschaft during his stays at INRIA Sophia Antipolis.     

A multidimensional extension to Hirsch’s h-index

The h-index is becoming a reference tool for career assessment and it is starting to be considered by some agencies and institutions in promotion, allocation, and funding decisions. In areas where h indices tend to be low, individuals with different research accomplishments may end up with the same h. This paper proposes a multidimensional extension of the h index in which the conventional h is only the first component. Additional components of the multidimensional index are obtained by computing the h-index for the subset of papers not considered in the immediately preceding component. Computation of the multidimensional index for 204 faculty members in Departments of Methodology of the Behavioral Sciences in Spain shows that individuals with the same h can indeed be distinguished by their values in the remaining components, and that the strength of the correlation of the second and third components of the multidimensional index with alternative bibliometric indicators is similar to that of the first component (i.e., the original h).     

Computer-aided statistical quality control in a concrete block factory in Kuwait

This paper describes the computer-aided statistical Quality Control Program developed for a factory in Kuwait to monitor the manufacturing of concrete blocks. The monitoring was carried out by analyzing variations in the dry density and thermal conductivity using a computer model “The CQC REPORT”. Analyses of both sets of data showed that the manufacturing process is in statistical control and is free of major assignable causes. However, some variables exhibited signs of instability and required adjustments before the process went out of control. The most urgent adjustements include: a) correcting downward the average density and thermal conductivity of the concrete; and b) arresting a descending trend in the overall quality of the concrete. Control over the density testing procedures was found adequate with a gradual improvement from “Very Good” to “Excellent”. Control over the thermal conductivity testing was observed to vary from “Good” to “Very Good” and then back to “Good”. These variations are believed to be caused by initial variations in testing procedures and the change in the testing equipment. Since these causes are of a temporary nature, their adverse effects on QC chart patterns were not expected to last long. For this reason, prior to making any adjustments, it was first recommended to discard initial readings, collect new data and analyze new charts for possible assignable causes. Analyses of the test data also revealed a need for adjustments to the trial control limits in the thermal conductivity state of the control chart as well as to the rating system in the standard deviation density chart. These adjustments can be performed later as more data become available.     

Comparison of reporting of seat belt use by police and crash investigators: variation in agreement by injury severity

Purpose: To evaluate agreement between police and trained investigators regarding seat belt use by crash victims, according to injury severity. Methods: We used data from the National Accident Sampling System Crashworthiness Data System (CDS) for front seat occupants, 16 years and older, in crashes during 1993–2000. Crashworthiness Data System investigators determined belt use from vehicle inspection, interviews, and medical record information; their assessment was considered the gold standard for this analysis. Occupant severity of injury was categorized in five levels from no injuries to death. We estimated the sensitivity, specificity, and area under receiver operating characteristic curves for police reports of belt use. Results: Among 48,858 occupants, sensitivity of a police report that a belt was used was 95.8% overall and varied only modestly by injury severity. Specificity of a police report that a belt was not used was 69.1% overall; it was the lowest among the uninjured (53.2%) and greatest among the dead (90.4%). The area under the curve was 0.82 (95% confidence interval 0.82–0.83) overall; this was lowest among those not injured (0.75, 95% confidence interval 0.74–0.76) and increased with injury severity to 0.91 (95% confidence interval 0.90–0.93) among those who died. Conclusion: Police usually classify belted crash victims as belted, regardless of injury severity. But they often classify unbelted survivors as belted when they were not. This misclassification may result in exaggerated estimates of seat belt effectiveness in some studies.     

Measurement of the relationship between perceived and computed color differences

Using simulated data sets, we have analyzed some mathematical properties of different statistical measurements that have been employed in previous literature to test the performance of different color-difference formulas. Specifically, the properties of the combined index PF/3 (performance factor obtained as average of three terms), widely employed in current literature, have been considered. A new index named standardized residual sum of squares (STRESS), employed in multidimensional scaling techniques, is recommended. The main difference between PF/3 and STRESS is that the latter is simpler and allows inferences on the statistical significance of two color-difference formulas with respect to a given set of visual data.     

Determination of saikosaponin derivatives in Radix bupleuri and in pharmaceuticals of the chinese multiherb remedy xiaochaihu-tang using liquid chromatographic tandem mass spectrometry

Saikosaponins are bioactive oleanane saponins derived from the Chinese medicinal herb Radix bupleuri ("chaihu" in Chinese). An LC-MS/MS-based method has been developed for characterization and quantification of 15 saikosaponin derivatives (saikosaponin a, saikosaponin b(1), saikosaponin g, saikogenin A, saikogenin H, saikosaponin c, saikosaponin h, saikosaponin i, prosaikogenin C(2), prosaikogenin B(2), saikogenin C, saikogenin B, saikosaponin d, saikosaponin b(2), and saikogenin D) in one chromatographic run. Optimization of the ionization process was performed with electrospray and atmospheric pressure chemical ionization techniques in both positive and negative ion modes. Negative ion ESI was adopted for generation of the precursor deprotonated molecules to achieve the best ionization sensitivity for the analytes. In addition, the most abundant fragment ion was chosen for each analyte to give the best CID sensitivity. Because some of the saponin derivatives are isomeric, complete resolution for the whole analytes was achieved both chromatographically and mass spectroscopically. Furthermore, optimal internal standard was successfully discovered for determination of the analytes by making use of a combinatorial chemistry approach. Good linearity over the range approximately 1.65 or 4.98 to 1200 ng/mL for the analytes was observed. The intraday accuracy and precision at nominal low, intermediate, and high concentration varied between 0.8 and 11.8% and between 80 and 116%, respectively, whereas those for interday assay were between 1.1 and 15.5% and between 86 and 119%, respectively. The lower limits of quantitation for the test compounds were approximately 16.5 to 49.4 pg on-column. The new method offered higher sensitivity and greater specificity than previously reported LC methods. After the validation, the applicability of the method for determination of these chemicals present in a variety of crude chaihu roots and in different brands of the Chinese multiherb remedy Xiaochaihu-tang (or Shosaiko-to) extract granules has been demonstrated. The sensitivity and specificity of the technique will be the basis of a method for the accurate quantification of the saikosaponin derivatives in biomatrixes.     

The effect of ISO quality management system standards on industrial property rights in Turkey

The aim of this study was to assess whether the systematical application of the following ISO quality management system standards: ISO 9001 (Quality Management System), ISO 22000 (Food Safety Management System), ISO 14001 (Environment Management System), ISO 13425 (Medical Device Quality Management System), ISO 27001 (Information Security Management System) and ISO 16949 (Automotive Quality Management System) have had an effect on the emergence of industrial property rights in Turkey. Information was collected about the number of ISO standard certification documents that Turkish organizations received in respect of these standards between the period of 2007 and 2013. For the same period, information about the number of granted patents, petty patents, trademarks and industrial designs in Turkey were also collected. The information was analyzed by year, industrial property right type and ISO standard. A Spearman correlation analysis was also conducted to determine the strength of association between the number of certification documents and the number of granted industrial property rights. The analysis showed that some of the ISO standards had either a positive or negative linear relationship with one or more of the granted industrial property right types. Although the total number of certification documents had decreased over the time period of the study, the number of granted industrial property rights in Turkey had increased over the same period indicating that the adoption of quality managment system standards may have led to an increase in national innovation in Turkey. This observation may help to improve innovation in other countries similar to Turkey.     

Chiral separation of alkylamine antihistamines in pharmaceuticals by capillary isotachophoresis with charged cyclodextrin

Cyclodextrin-mediated capillary isotachophoresis (ITP) in cationic regime of the separation was developed for the separation and quantitation of alkylamine antihistamine dimethindene (DIM) and pheniramine (PHM) enantiomers in various pharmaceutical preparations (capsules, oral drops, gel, granulated powder). Several electrolyte systems of different compositions and pH were examined. The optimized chiral ITP electrolyte system was consisted of 10 mmol/L potassium acetate adjusted to pH 4.8 with acetic acid, containing 4 mmol/L negatively charged CE-β-CD (chiral selector) as the leading electrolyte with electroosmotic flow (EOF) suppressing additive, 0.2% (w/v) methylhydroxyethylcellulose (m-HEC), and 5 mmol/L β-alanine as the terminating electrolyte. The proposed electrophoretic method was successfully validated. It was convenient for the sensitive, simple, rapid, and highly reproducible assay of these antihistamine enantiomers. The calibration graphs relating the ITP zone length to the concentration of DIM and PHM enantiomers were rectilinear (r = 0.999) in the range 40.0-200.0 mg/L of each enantiomer. The relative standard deviations (RSD) were 0.75% for DIM(1), 0.63% for DIM(2), 1.05% for PHM(1), and 0.83% for PHM(2) (n = 6) when determining 100 mg/L DIM and PHM, respectively, standard solutions. According to the validation procedure based on the standard addition technique the recoveries were 97.66-98.34%. Good quantitation was obtained in short analysis time (a single analysis took about 12 min). The minimal sample pretreatment and low running costs make the proposed ITP method a good alternative to commonly used analytical methods (CZE, HPLC). The obtained results suggest that the proposed method is suitable for routine assay of dimethindene and pheniramine enantiomers in various pharmaceuticals.     

Attention deficit and hyperactivity disorder tendency and unintentional injury among adolescents in China

This study aims to investigate the association between ADD tendency, with or without hyperactivity, and all types of unintentional injuries among adolescents. This study was a population-based health survey utilising a two-stage random cluster sampling design. The study was conducted among high school students in Nanning, the capital city of the Guangxi Province, China. Subjects were recruited from the total population of adolescents who attended high school years 1, 2, and 3 with ages ranging from 13 to 17 years. Information on ADD was collected by trained health professional via personal interviews. Other information, including unintentional injury was collected via a self-report health survey questionnaire. One thousand and twenty-nine (n = 1429) students were recruited with 115 (7.9%) identified as having a high ADD tendency, and 340 (22.6%) reported as having experienced an injury in the last 3 months. After adjusting for other potential confounding factors, results from the logistic regression analyses indicated that adolescents who scored high on the ADD tendency had an increased risk of injury by about 70% as compared to those who scored low (OR = 1.68, 95%CI = 1.18–2.40). ADD tendency has been identified as a potential risk factor of injury among adolescents. Screening for risk factors can be considered as a potential preventive strategy.     

小型高速艇舱室减振降噪设计

小型高速艇的减振降噪是近几年经起重视的，本文通过对间接的，有限的噪声振动源资源的分析研究，预估了一类小型高速艇各舱室的噪声级，根据国外近期同类艇的噪声水平以及总体减振降噪和多方面约束条件综合测定了该艇的减振降噪方案，并在此基础上进行了声强激励和振动激励条件下舱室模型综合减振降噪效果试验，结果表明，所制定的减振降噪方案其效果良好，实艇实测结果达到设计指标要求。     

Study Habits and Academic Achievement of Engineering Students

A study habits index measuring distractibility, inquisitiveness, and compulsiveness in test and homework situations was administered to 69 (27 women and 42 men) first-year, college engineering students. Scholastic Aptitude Test (SAT) scores and grade-point averages were also obtained. Two hypotheses were entertained: a) students who earn the highest grades, in contrast to less successful peers, will tend to be less distractible and more inquisitive; b) the advantage of such study habits will be evident when effects of academic aptitude (SAT performance) are controlled. Statistical tests supported both hypotheses. No significant sex differences were found for aptitude or grades, but women scored higher on the compulsiveness study habits scale than men. We argue that special programs to help some students study more meaningfully would likely improve overall academic performance.     

表面活性剂对羟基磷灰石纤维形貌的影响

以Ca(NO₃)₂·4H₂O和(NH₄)₂HPO₄水溶液为前驱体, 采用水热均相沉淀法制备了结晶度较高的羟基磷灰石纤维, 研究了表面活性剂十六烷基三甲基溴化胺(CTAB)、十二烷基硫酸钠(SDS)和聚乙二醇(PEG)及其含量对产物形貌和相组成的影响。结果表明, 采用这三种表面活性剂制备的产物都是羟基磷灰石, 部分样品含有少量碳酸钙杂质。加入CTAB和SDS均会对纤维的生长起到抑制作用, 得到纤维与球形团聚体并存的产物, 而PEG的加入在一定程度上促进了纤维的生长。     

Depressive symptom severity,contributing factors,and self‐management among chronic dialysis patients

Despite the high prevalence of depressive symptoms in patients receiving chronic dialysis, there has been inadequate attention to patient‐related barriers to management of depressive symptoms, such as factors identified by these patients as contributing to their symptoms, and how they responded to the symptoms. Participants (N = 210) in an ongoing longitudinal observational study of multidimensional quality of life in patients receiving chronic dialysis completed a battery of measures monthly for 12 months. For each patient at each measurement point, an event report was generated if he or she scored outside of the normal range on the depressive symptom scale (Center for Epidemiologic Studies Depression Scale‐Short Form [CESD‐SF] ≥10) or expressed suicidal ideation. Of the 210 participants, 100 (47.6%) had a CESD‐SF score ≥10 at least once resulting in 290 event reports. Of these 100 participants, 15 (15%) had also reported suicidal ideation in addition to having depressive symptoms. The most frequently stated contributing factors included “managing comorbid conditions and complications” (56 event reports, 19.3%), “being on dialysis” (50, 17.2%), “family or other personal issues” (37, 12.8%), and “financial difficulties” (31, 10.7%). On 11 event reports (3.8%) participants had been unaware of their depressive symptoms. On 119 event reports (41%) participants reported that they discussed these symptoms with their dialysis care providers or primary care providers, while on 171 event reports (59%) symptoms were not discussed with their health‐care providers. The prevalence of depressive symptoms is high and many patients lack knowledge about effective self‐management strategies.