scholarly journals Some aspects of physical and mechanical properties of hollow blocks procuced from hot water treated sawdust.

Author(s):  
David Ekhuemelo ◽  
Emmanuel Terzungwue Tembe ◽  
Awa Mike Versue

The study investigated sawdust as a partial replacement for sand in production of hollow blocks with a view to reducing cost and converting waste to resource use. Sawdust of Daniella oliveri was collected from Timber Shed along New Bridge Wurukum, Makurdi. It was boiled and spread to dry. Standard ratio of 1:8 (cement and sand) was used in the study. Replacement levels of 0%, 2%, 4%, 6% and 8% of sawdust were used for sand, while cement was kept constant throughout the mixture. Density, percentage water absorption (PWA), and compressive strength (CS) of the blocks were tested after 28 days of curing. PWA results showed that blocks produced from 0% sawdust replacement level had least mean of 10.06%, while 8% sawdust replacement had the highest mean of 11.40%. Mean density values showed that 8% sawdust replacement had the least value of 1090.40Kg/m3 and while the highest value (1346.60Kg) was observed for 0%. The mean CS for 0% sawdust replacement was highest (3.20N/mm2)and falls within the Nigeria Building Codes of 2.5N/mm2 - 3.45N/mm2 and Ghana Building Code of 2.75 N/mm2. Mean CS value of 2.0N/mm2 was obtained for 2% and 4% sawdust replacement levels respectively. The value  meets the minimum standard of 2.0N/mm2 according to National Building Code for non-load bearing walls and 1.7 N/mm2 according to Ghana Building Code. However, 6% and 8% sawdust replacement levels showed the least CS of 1.00N/mm2 which is below standards. In conclusion, blocks produced with 2% and 4% sawdust replacement levels as obtained in this study are recommended for building and construction purposes.Keywords: Blocks, Building code, cement, sand, sawdust, standard

2015 ◽  
Vol 824 ◽  
pp. 39-42
Author(s):  
Eva Vejmelková ◽  
Monika Čáchová ◽  
Jaroslava Koťátková

Crushed brick (CB) used in high strength concrete as partial replacement of cement is the subject of this paper. It is a waste material and so its exploitation is needed to be found. Concrete industry can be proper area as CB is a fine material and is pozzolanic active. Basic physical properties and mechanical properties were investigated. Open porosity and bulk density achieved the best values when 30% of cement was replaced by CB. Matrix density decreased with rising addition ratio. The values of compressive strength was the highest for 30% replacement level and with 60% addition ratio were not lower than for the reference mixture. The conclusion is, that according to studied parameters 30% of cement substituted by CB is the most profitable addition ratio.


2017 ◽  
Vol 866 ◽  
pp. 199-203
Author(s):  
Chidchanok Chainej ◽  
Suparut Narksitipan ◽  
Nittaya Jaitanong

The aims of this research were study the microstructures and mechanical properties for partial replacement of cement with Fly ash (FA) and kaolin waste (KW). Ordinary Portland cement were partially replaced with FA and KW in the range of 25-35% and 10-25% by weight of cement powder. The kaolin waste was ground for 180 minutes before using. The specimen was packing into an iron mold which sample size of 5×5×5 cm3. Then, the specimens were kept at room temperature for 24 hours and were moist cured in the incubation lime water bath at age of 3 days. After that the specimens were dry cured with plastic wrap at age of 3, 7, 14 and 28 days. After that the compounds were examined by x-ray diffraction patterns (XRD) and the microstructures were examined by scanning electron microscopy (SEM). The compressive strength was then investigated.


Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 113
Author(s):  
Lech W. Szajdak ◽  
Teresa Meysner ◽  
Marek Szczepański

The aim of this study is to comprehensively assess the change in oxidoreductive enzyme activities, due to the potential in catalyzing oxidation and reduction reactions, as the basic processes on undrained and drained peat soils. On undrained peatlands, a significant decrease of enzyme activities was observed such as xanthine oxidase, urate oxidase, phenol oxidase, and peroxidase with an increase in depth. It was connected with significantly higher porosity values, hot water extractable organic carbon, and total organic nitrogen contents, ammonium and nitrate ions concentrations, and significantly lower ash and bulk density values in the upper layers. On drained peatlands, a significant increase of enzyme activities in depth was measured. Enzyme activities such as xanthine, urate, phenol oxidase, and peroxidase were documented to be effective as new indicators and tools for changes of the moorsh-forming process in association with the oscillation of the water table caused by the drainage of the peatlands.


Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1460
Author(s):  
Jiaxin Chen ◽  
Jinhai Zhao ◽  
Xin Li ◽  
Qian Liu ◽  
Baohua Kong

The effect of the partial replacement of pork back-fat with a cube fat substitute (CFS) fabricated from konjac glucomannan and carrageenan on the physicochemical and sensory characteristics of Harbin dry sausages during 7 days of fermentation was investigated. There were the following five treatments: control (100% back-fat), FS1 (80% back-fat, 20% CFS), FS2 (60% back-fat, 40% CFS), FS3 (40% back-fat, 60% CFS) and FS4 (20% back-fat, 80% CFS). The results showed no significant differences (p > 0.05) in the physicochemical and sensory characteristics among the control, FS1 and FS2 treatments. However, higher replacement levels (60% and 80%) rendered higher degrees of change in the characteristics of the sausages, lowering the moisture content and aw and increasing the pH, hardness, chewiness and atypical appearance at the end of fermentation. Moreover, electronic nose analysis and hierarchical cluster analysis demonstrated that the FS3 and FS4 treatments destroyed the characteristic quality of the sausage. Overall, our results indicated that, to ensure the traditional characteristics of Harbin dry sausages, the upper limit of the fat replacement level with CFS should be set at 40%.


Author(s):  
V. V. Kulakov ◽  
M. I. Pankov ◽  
V. A. Sivurova ◽  
M. S. Luchkin ◽  
A. K. Golubkov ◽  
...  

The efficiency of the pyrolytic carbon compaction process by decomposing methane in samples of a carbon-carbon composite randomly reinforced with discrete high-modulus (graphitized) carbon fibers with different densities is investigated. The analysis of the test results of samples for determining the compressive strength, determining the densities of samples after compaction with pyrocarbon and after compaction by impregnation and carbonization under pressure is carried out. Scanning electron microscopy (SEM) was used to study the structure of material samples with different initial density values.


2021 ◽  
Author(s):  
Étienne Chassé ◽  
Daniel Théoret ◽  
Martin P Poirier ◽  
François Lalonde

ABSTRACT Introduction Members of the Canadian Armed Forces (CAF) are required to meet the minimum standards of the Fitness for Operational Requirements of CAF Employment (FORCE) job-based simulation test (JBST) and must possess the capacity to perform other common essential tasks. One of those tasks is to perform basic fire management tasks during fire emergencies to mitigate damage and reduce the risk of injuries and/or death until professional firefighters arrive at the scene. To date however, the physiological demands of common firefighting tasks have mostly been performed on professional firefighters, thus rendering the transferability of the demands to the general military population unclear. This pilot study aimed to quantify, for the first time, the physiological demands of basic fire management tasks in the military, to determine if they are reflected in the FORCE JBST minimum standard. We hypothesized that the physiological demands of basic fire management tasks within the CAF are below the physiological demands of the FORCE JBST minimum standard, and as such, be lower than the demands of professional firefighting. Materials and methods To achieve this, 21 CAF members (8 females; 13 males; mean [SD] age: 33 [10] years; height: 174.5 [10.5] cm; weight: 85.4 [22.1] kg, estimated maximal oxygen uptake [$\dot V$O2peak]: 44.4 (7.4) mL kg−1 min−1) participated in a realistic, but physically demanding, JBST developed by CAF professional firefighting subject matter experts. The actions included lifting, carrying, and manipulating a 13-kg powder fire extinguisher and connecting, coupling, and dragging a 38-mm fire hose over 30 m. The rate of oxygen uptake ($\dot V$O2), heart rate, and percentage of heart rate reserve were measured continuously during two task simulation trials, which were interspersed by a recovery period. Rating of perceived exertion (6-no exertion; 20-maximal exertion) was measured upon completion of both task simulations. Peak $\dot V$O2 ($\dot V$O2peak) was estimated based on the results of the FORCE JBST. Results The mean (SD) duration of both task simulation trials was 3:39 (0:19) min:s, whereas the rest period in between both trials was 62 (19) minutes. The mean O2 was 21.1 (4.7) mL kg−1 min−1 across trials, which represented 52.1 (12.2) %$\dot V$O2peak and ∼81% of the FORCE JBST. This was paralleled by a mean heart rate of 136 (18) beats min−1, mean percentage of heart rate reserve of 61.2 (10.8), and mean rating of perceived exertion of 11 ± 2. Other physical components of the JBST consisted of lifting, carrying, and manipulating a 13-kg load for ∼59 seconds, which represents 65% of the load of the FORCE JBST. The external resistance of the fire hose drag portion increased up to 316 N, translating to a total of 6205 N over 30 m, which represents 96% of the drag force measured during the FORCE JBST. Conclusions Our findings demonstrate that the physiological demands of basic fire management tasks in the CAF are of moderate intensity, which are reflected in the CAF physical fitness standard. As such, CAF members who achieve the minimum standard on the FORCE JBST are deemed capable of physically performing basic fire management tasks during fire emergencies.


2013 ◽  
Vol 96 (3) ◽  
pp. 567-572 ◽  
Author(s):  
Rebecca M Pines ◽  
Stephen F Tomasino ◽  
Michele P Cottrill ◽  
Gordon C Hamilton ◽  
Albert E Parker

Abstract The AOAC Germicidal Spray Products as Disinfectants test method (AOAC Official Method 961.02) is used to measure the efficacy of spray products on hard inanimate surfaces; however, the method does not provide procedures to determine the population of the test microbe on inoculated glass slide carriers (e.g., carrier counts reported as CFU/carrier). Without a method to measure and monitor carrier counts, the associated efficacy data may not be reliable and repeatable. This report provides a standardized procedure to address this issue and, based on carrier count data collected by four laboratories from 2000 to 2010, proposes a specific range for the mean log density per carrier as a requirement. Laboratory-based carrier count data were collected concurrently with 116 Method 961.02 efficacy tests conducted on spray products bearing claims against Pseudomonas aeruginosa and Staphylococcus aureus. For many of the tests a soil load (SL) was added to the inoculum (as specified on the product label claim). Six carriers were assayed per test for a total of 696 carriers. All but two of the 116 mean log densities were at least 5.0 (a geometric mean of 1.0 × 105 CFU/carrier). Across the four combinations of microbes and SL treatments, the mean TestLD (mean log density across all enumerated carriers in a test) ranged from approximately 6.0 (a geometric mean of 0.9 × 106 CFU/carrier) to 6.3 (a geometric mean of 2.0 × 106 CFU/carrier). Across all microbes and SL treatments, the mean log density (±SEM) was 6.2 (±0.07) per carrier (a geometric mean of 1.5 × 106 CFU/carrier). The mean log density for six carriers per test showed good repeatability (0.32) and reproducibility (0.34). The proposed requirement for S. aureus tests and P. aeruginosa tests is a mean log density (across six carriers) between 5.0 and 6.5. A separate 2009 study at three laboratories was conducted to evaluate the persistence of P. aeruginosa, S. aureus, and Salmonella enterica on glass carriers. Based on the persistence data, a 2 h use period is proposed for using the inoculated carriers post drying. The persistence data set was also used to assess the carrier counts for S. enterica. The carrier counts were approximately one log lower for S. enterica compared to S. aureus and P. aeruginosa; a range of 4.0 to 5.5 logs is proposed as a requirement for S. enterica tests.


2011 ◽  
Vol 101 (1-2) ◽  
pp. 5-14 ◽  
Author(s):  
Douglas F Peiró ◽  
Fernando L Mantelatto

The Pinnotheridae family is one of the most diverse and complex groups of brachyuran crabs, many of them symbionts of a wide variety of invertebrates. The present study describes the population dynamics of the pea crab Austinixa aidae (Righi, 1967), a symbiont associated with the burrows of the ghost shrimp Callichirus major (Say, 1818). Individuals (n = 588) were collected bimonthly from May, 2005 to September, 2006 along a sandy beach in the southwestern Atlantic, state of São Paulo, Brazil. Our data indicated that the population demography of A. aidae was characterized by a bimodal size-frequency distribution (between 2.0 and 4.0 mm and between 8.0 and 9.0 mm CW) that remained similar throughout the study period. Sex ratio does not differ significantly from 1:1 (p > 0.05), which confirms the pattern observed in other symbiontic pinnotherids. Density values (1.72 ± 1.34 ind. • ap.-1) are in agreement with those found for other species of the genus. The mean symbiosis incidence (75.6%) was one of the highest among species of the Pinnotheridae family, but it was the lowest among the three studied species of the genus. Recruitment pattern was annual, beginning in May and peaking in July, in both years, after the peak of ovigerous females in the population (from March to May). Our findings describe ecological and biological aspects of A. aidae similar to those of other species of this genus, even from different geographic localities.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2154-2154
Author(s):  
Emma Hernlund ◽  
Josefine Redig ◽  
Åsa Rangert Derolf ◽  
Bjorn Paulsson ◽  
Martin Höglund ◽  
...  

Introduction: AML affects all ages with an incidence rate of 5 per 100,000, but is much more frequent in older population. The overall lifetime risk of AML is estimated to be 0.5-1%. Long-term overall survival in younger (age < 60 years) is about 50%, but much worse among older population. Although AML therapy is one of the most resource-intensive cancer treatments, there are few estimates of the resource use and economic burden by treatment phase. Methods: This study was a retrospective database study performed on Swedish national data. Adult patients (age ≥18 years) diagnosed with AML in Sweden between 2007 and 2015 were identified in the Swedish Cancer Registry, along with vital status. Data on resource use were collected from national registers for inpatient- and outpatient specialized care and prescribed drugs. Information on diagnostics and treatment was accessed from the Swedish national AML Registry (SwAMLR). Data on sick leave (SL) and early retirement (ER) came from the Swedish Social Insurance Agency (absent days costed with the mean salary in Sweden). Hospital care resource use was costed using diagnosis-related group (DRG) remunerations, and include cost of inpatient drugs. The mean cost from the defined start of the treatment phase until the end of the treatment phase was divided by the mean number of days for the corresponding treatment phase to estimate the mean cost per day. The defined treatment phases were restricted to a maximum of 5 years. All costs are represented in US$. Results: Of the 2,954 patients identified in the Swedish Cancer Registry, 1,772 patients with a median age of 64 years were identified in the SwAMLR as fit for receiving high-dose chemotherapy . Of these, 1,243 were recorded with both curative intent of treatment and dates for achieving complete remission. Mean costs from the first AML-related hospital admission until the date of complete remission amount to $27,244. The mean number of days for the corresponding period were 45.16, resulting in a mean cost per day of $603 from first admission to first complete remission. The corresponding cost per day for patients recorded with curative intent but no complete remission (n=428) are $494. Time was counted from first AML-related admission until 90 days after first admission, or SCT or death, whichever occurred first. Costs after complete remission to either relapse, SCT, death or re-induction (n=1,237) amount to $50,793 for a mean of 438.63 days ($116/day). This treatment phase includes long-term survivors, whereas the costs from SCT, relapse or re-induction are not included. From relapse to death, the total cost is almost twofold for patients with re-induction (n=350) compared to palliative treatment (n=254). Cost per day amount to $179 for patients with palliative treatment and $256 for patients with re-induction treatment, respectively. The cost per day from date of SCT to death (n=511) is estimated to $192, incurred over a long period of time (mean number of days 844.02). The age of transplant recipients ranged between 18-71 years, with a median of 52 years. Conclusions: Costs of AML up to remission are feasible to estimate through DRG-costing methods, and studies have shown these costs are intense. Indeed this study shows that the highest cost per day is observed from first admission to complete remission. In addition results from our study show that there are high costs incurred also in the long-term, i.e. after remission. Of the included treatment phases the total cost from date of SCT to death is the largest, amounting to over $160,000. Approximately 20% are due to SL/ER, which is the second largest cost component after inpatient costs accounting for 60% of the total costs. Table. Disclosures Hernlund: ICON: Employment. Redig:ICON: Employment. Paulsson:Novartis: Employment. Vertuani:Novartis: Employment.


Author(s):  
Adeniran Jolaade ADEALA ◽  
Olugbenga Babajide SOYEM

Expanded polystyrene (EPS) wastes are generated from industries and post-consumer products. They are non-biodegradable but are usually disposed by burning or landfilling leading to environmental pollution. The possibility of using EPS as partial replacement for fine aggregates in concrete has generated research interests in recent times. However, since the physical and mechanical properties of EPS are not like those of conventional fine aggregates, this study is focussed on the use of EPS as an additive in concrete while keeping other composition (sand and granite) constant. Expanded polystyrene was milled, the bulk density of EPS was 10.57kg/m3 and particle size distributions were determined. Engineering properties of expanded polystyrene concrete were determined in accordance with BS 8110-2:1985. The result showed that the amount of expanded polystyrene incorporated in concrete influence the properties of hardened and fresh concrete. The compressive strengths of 17.07MPa with 5 % expanded polystyrene concrete at 28 days for example can be used as a lightweight concrete for partitioning in offices. Incorporating expanded polystyrene granules in a concrete matrix can produce lightweight polystyrene aggregate concrete of various densities, compressive strengths, flexural strengths and tensile strengths. In conclusion, this reduces environmental pollution, reduction in valuable landfill space and also for sustainability in construction companies


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