Properties of Self-Compacting Mortar made with Sorghum Husk Ash and Calcium Carbide Waste as Binder

The quest for the development of alternative and more sustainable construction material stemmed out from the current global concern on issues relating to global warming and green house effect. In recent time, research direction has shifted towards the use of agro-industrial waste as complete replacement of ordinary Portland cement. In this study the effects of the blends of sorghum husk ash (SHA) and calcium carbide waste (CCW) on the fresh properties of self compacting mortar was investigated where various tests were carried out which included physical and chemical properties of the constituents materials, Flow cone test for paste, Mini v-funnel flow time and Mortar flow spread test for determination of saturation dosage of HRWR for self compacting mortar made with sorghum husk ash and calcium carbide waste as binder, were carried out. Then developments in the compressive strength of the hardened mortar were determined at 3, 7, 14, 28, 56 and 90 days. The study revealed that SHA sample have high Silicon dioxide (SiO2 (84%) while CCW is majorly Calcium oxide (CaO(66%).The optimum saturation dosage of  High Range Water Reducer  (HRWR) determined from Flow cone test and Mini-v-funnel was 3.5%. The 70/30 (SHA/CCW) shows the highest mortar flow spread of 290 mm compared to the control (295mm).The agro-industrial binder exhibited good binding properties at a slow hydration rate. Analysis of the compressive strength results show that 70/30 (SHA/CCW) proportion has the highest value of 14.08 N/mm2 at 90 days. Self compacting mortar made with SHA/CCW combinations as binder can be adopted for use in masonry work as it conforms to type N of ASTM C270 morta

Description and Composition of Tree Species in a Tertiary Institution Agricultural Faculty Arboretum, Ibadan, South-West Nigeria

The Arboretum of the Agricultural Faculty of a tertiary institution in Ibadan is known for its rich diversity of trees. Therefore, the study investigates the tree growth variables in the arboretum such as diameter at breast height (dbh), diameter at the base, middle and top of the bole, total height, merchantable height and crown diameter. The basal area and volume were then calculated per species and per family. Several models were fitted for the height – diameter relationship and crown diameter – diameter relationship and crown diameter – dbh relationship. Positive linear relationships were observed among the growth variables. The fitted models showed that cubic models exhibit a more reliable function than quadratic and linear models for crown diameter – dbh predictions as it has R2 above 0.75. Endangered species were observed too and this was indicated through the diversity index obtained. The highest basal area encounter belongs to myrtaceae family (9.61m2) while the lowest belongs to pinaceae family (0.24m2). The total basal area obtained at (31.72m2) from the faculty trees indicates that they are exhibiting better growth and yield

Solar-eclipse-induced perturbations at mid-latitude during the 21 August 2017 event

A study of the response of some ionospheric parameters and their relationship in describing the behaviour of ionospheric mechanisms during the solar eclipse of 21 August 2017 is presented. Mid-latitude stations located along the eclipse path and with data available from the Global Ionospheric radio Observatory (GIRO) database were selected. The percentage of obscuration at these stations ranges between 63&thinsp;% and 100&thinsp;%. A decrease in electron density during the eclipse is attributed to a reduction in solar radiation and natural gas heating. The maximum magnitude of the eclipse consistently coincided with a hmF2 increase and with a lagged maximum decrease in NmF2 at the stations investigated. The results revealed that the horizontal neutral wind flow is as a consequence of the changes in the thermospheric and diffusion processes. The unusual increase and decrease in the shape and thickness parameters during the eclipse period relative to the control days points to the perturbation caused by the solar eclipse. The relationships of the bottomside ionosphere and the F2 layer parameters with respect to the scale height are shown in the present work as viable parameters for probing the topside ionosphere during the eclipse. Furthermore, this study shows that in addition to traditional ways of analysing the thermospheric composition and neutral wind flow, proper relation of standardized NmF2 and hmF2 can be conveniently used to describe the mechanisms.</p

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700