Evaluation of a Centrifuge Consolidation Technique to Determine the Effects of Temperature and Time on Kaolinite Properties

Abstract The effects of time and temperature on the moisture content and unit weight profiles, as developed during a centrifuge consolidation process, were observed during the research program that is described herein. Specifically, a Beckman-Coulter Model J6-MI centrifuge with a six-place JS-4.2A swinging bucket rotor was utilized to consolidate kaolinite slurry samples. The consolidation procedure utilized specially designed slurry consolidometers, made from acrylic tubes with inside diameters of 2.63 inches (6.67 cm) and heights of 5.13 inches (13.04 cm). The tested kaolinite slurry samples were created by mixing 400 grams of dry kaolinite clay powder with 200 grams of de-aired deionized water (DI water) to reach an initial water content of 50 percent. Temperatures of - 10, 0 and 20℃ were utilized within the centrifuge with spin times of 12, 18, 24, and 30 hours. After being removed from the centrifuge, each soil specimen was trimmed into multiple slices of approximately 0.25-inch (0.64 cm) thick. The unit weight and moisture content of each individual slice were calculated and reported. The slurry samples were spun at a fixed centrifugal force of 500 revolutions per minute (RPM) that corresponded to an effective stress at the bottom of the samples of 35.57 kPa at the temperature of -10℃, 50.30 kPa at the temperature of 0℃, and 52.47 kPa at the temperature 20℃. The average unit weight values of the spun samples at 30 hours was 15.52 kN/m3 at the temperature of -10℃, 17.91 kN/m3 at the temperature of 0℃, and 18.25 kN/m3 at the temperature of 20℃. Additionally, the average moisture content values of the spun samples at 30 hours samples were 41.90 percent, 31.22 percent, and 30.22 percent for the testing temperatures of - 10, 0 and 20, respectively

Systemic intervention for computer-supported collaborative learning

This paper presents a systemic intervention approach as a means to overcome the methodological challenges involved in research into computer-supported collaborative learning applied to the promotion of mathematical problem-solving (CSCL-MPS) skills in schools. These challenges include how to develop an integrated analysis of several aspects of the learning process; and how to reflect on learning purposes, the context of application and participants' identities. The focus of systemic intervention is on processes for thinking through whose views and what issues and values should be considered pertinent in an analysis. Systemic intervention also advocates mixing methods from different traditions to address the purposes of multiple stakeholders. Consequently, a design for CSCL-MPS research is presented that includes several methods. This methodological design is used to analyse and reflect upon both a CSCL-MPS project with Colombian schools, and the identities of the participants in that project

Satellites of Infinite Rank in the Smooth Concordance Group

We conjecture that satellite operations are either constant or have infinite rank in the concordance group. We reduce this to the difficult case of winding number zero satellites, and use $SO(3)$ gauge theory to provide a general criterion sufficient for the image of a satellite operation to generate an infinite rank subgroup of the smooth concordance group $\mathcal{C}$. Our criterion applies widely, notably to scores of unknotted patterns for which the corresponding operators on the topological concordance group are zero. We raise some questions and conjectures regarding satellite operators and their interaction with concordance

MANUAL DE LABORATORIO PARA BIOQUíMICA GENERAL DEL INGENIERO AGRóNOMO FITOTECNISTA

Manual para prácticas de laboratorio, taller u otra área de apoyo a la Docenci

Neuraminidase-activated microglia compromise the viability of ependymocytes

Neuraminidase (NA) is a sialidase present in the envelope/wall of some virus/bacteria responsible for brain infections, such as flu, mumps or meningitis. The intracerebroventricular injection of NA in the rat brain provokes ependymal detachment and death, and an acute inflammatory process. Although inflammation reverses, ependymal lining is not regenerated. Complement system activation within the CSF contributes to ependymal damage, but is not the only cause (Granados-Duran et al, 2016). Here we aimed to investigate if microglial activation might also play a role. For this purpose we used pure isolated ependymocytes (Grondona et al, 2013) and ventricular wall explants, which were co-cultured with microglial cells, both in basal conditions and with agents that induce microglial activation: NA, LPS, or Pam3CSK4 (synthetic lipopeptide). The viability of the ependymal cells was assessed by trypan blue exclusion. The viability of isolated ependymocytes was reduced when NA or LPS were added to the culture, compared to controls without additives. In the absence of microglia, NA or LPS did not compromise viability significantly, indicating that microglia was involved in ependymocytes death. The addition of NA to cultured explants reduced ependymocytes viability only when microglial cells were present in the culture; a similar reduction was observed when LPS or Pam3CSK4 were added. Conversely, explants cultured in the absence of microglia did not suffer a significant decrease in ependymocytes viability upon NA addition to the medium. We hypothesized that cytokines released by activated microglia, such as IL1β or TNFα, could mediate ependymocytes death. RT-PCR performed in RNA obtained from pure ependymocytes confirmed the presence of IL1β and TNFα receptors in ependymal cells. Nevertheless further experiments are required to confirm this hypothesis. We conclude that microglia activated by NA mediates, at least in part, ependymal cell death, what might be relevant for neuroinflammatory diseases mediated by NA bearing virus/bacteria.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Comparing the diversity, geographic distribution, and intraspecific variation of subterranean termites (Reticulitermes: Isoptera: Rhinotermitidae) occuring in woodlands and urban environments of Missouri using morphology and 16s mtDNA

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file (viewed on February 28, 2008)Vita.Thesis (Ph. D.) University of Missouri-Columbia 2007.Subterranean termite species in the genus Reticulitermes are ecologically and economically important in the United States. At least six species of the genus Reticulitermes are native from North American forests where they feed on cellulose materials. In urban environments they feed upon dead wood, and therefore infest and destroy man-made wooden structures. Missouri is considered to have a moderate risk for termite infestations when compared with the states of the southeast part of the country. Despite their ecological and economic importance, Missouri's subterranean termite faunal composition and geographic distribution is not well known. Diversity, geographic distribution, and genetic variability of Reticulitermes species within Missouri were studied from approximately 600 samples of termite colonies collected during 2004 and 2005 in nine conservation areas, nine cities located near these conservation areas, and from home infestations occurring at many different locations within the state. Reticulitermes flavipes (Kollar), Reticulitermes virginicus (Banks), Reticulitermes tibialis Banks and Reticulitermes hageni Banks were found occurring in Missouri. Reticulitermes flavipes and R. hageni were the most abundant species. Reticulitermes flavipes was found to be more abundant in urban environments and home infestations than in woodlands. Reticulitermes hageni also occurs throughout the state but was found to be more abundant in woodlands than in urban environments. This study updated the inventory of Reticulitermes species occurring within the state, provided new records of occurrence of the species in geographical locations not known before, and provided a comprehensive morphometric study of soldiers of Reticulitermes species occurring in both urban and woodlands of Missouri. Ecological studies as well as integrated management may benefit from the information provided in this study.Includes bibliographical reference

Hubungan Indeks Massa Tubuh dengan Kapasitas Vital Paru-paru Golongan Usia Muda

Obesity is one of the risk factors for many metabolic and cardiovascular diseases. Vital capacity measurement is one of the health procedures to show lung function. Vital capacity can be predicted by knowing age and height. Vital capacity percentage shows the result of vital capacity in measurement compared with the predicted vital capacity. Sixty six healthy volunteers (n=66) are used in this study. The results show that vital capacity percentage are higher in normal-thin volunteers with % RBW (Relative Body Weight) < 90% than the normal-normal high weight volunteers with % RBW (Relative Body Weight) < 90-110%. If the findings are compared by using statistical methods, the results show no significance differences (p>0,05)