Variation In Results Research Articles

Response surface methodology and desirability approach to investigate and optimize the performance of a CO2 geothermal thermosyphon

Geothermal thermosyphons (GTs) are increasingly used in many heating and cooling geothermal applications, owing to their high heat transfer performance. In this paper a combined response surface methodology and multi-objective desirability method is proposed for the investigation and optimization of the thermal performance of a geothermal thermosyphon. The filling ratio, temperature, and flow rate of the heat transfer fluid are selected as the designing parameters, and heat transfer rate and effectiveness are adopted as response parameters (objective functions). First, a dedicated experimental GT test bench filled with carbon dioxide (CO2) was built and subjected to different test conditions defined by RSM. A multi-level design of experiment-based response surface methodology (RSM) was used to establish corresponding models between the input parameters and responses. Various diagnostic tests were used to evaluate the quality and validity of the best-fit models, which explain respectively 98.9 and 99.2% of the output result's variability. Further, a surface response analysis of the effect of each input parameter on the responses was performed and a desirability function-based model was employed to determine the optimal combination of factors that would maximize the desired responses. The results revealed that the parameter-setting obtained using the proposed procedure satisfies the requirements of each response, with a desirability of 0.98.

Adoption of Emerging Technologies by Major Enterprise Data Storage Organizations - Factors, Strategies, and Benefits

Modern problems require modern solutions. The global Enterprise Data Storage organizations are constantly innovating, redefining, and re-engineering their strategies to sustain, survive and succeed. The key to success lies in consistent performance. This study is aimed to understand the influencing factors to tackle the technological challenges leading to the adoption of emerging technologies to remain viable in the market for continuous customer success. The study is primarily focused on 5-6 organizations constantly featured as “Leaders” in Gartner Magic Quadrant for Primary Storage Arrays in 3-5 years. A conceptual framework will be constructed to establish and ascertain the relationship between the Technology Adoption Drivers (TAD), Technology Variables (TV), and Resultant Variables (RV) to indicate the impacts of strategic adoption of emerging technologies.

Factors Contributing to Variability of Quantitative Viral PCR Results in Proficiency Testing Samples: a Multivariate Analysis

While viral load testing has gained widespread acceptance, a primary limitation remains the variability of results, particularly between different laboratories. While some work has demonstrated the importance of standardized quantitative control material in reducing this variability, little has been done to explore other important factors in the molecular amplification process. Results of 185 laboratories enrolled in the College of American Pathologists (CAP) 2009 viral load proficiency testing (PT) survey (VLS) were examined. This included 165 labs (89.2%) testing for cytomegalovirus (CMV), 99 (53.5%) for Epstein-Barr virus (EBV), and 64 (34.6%) for BK virus (BKV). At the time of PT, laboratories were asked a series of questions to characterize their testing methods. The responses to these questions were correlated to mean viral load (MVL) and result variability (RV). Contribution of individual factors to RV was estimated through analysis of variance (ANOVA) modeling and the use of backward selection of factors to fit those models. Selection of the quantitative calibrator, commercially prepared primers and probes, and amplification target gene were found most prominently associated with changes in MVL or RV for one or more of the viruses studied. Commercially prepared primers and probes and amplification target gene made the largest contribution to overall variability. Factors contributing to MVL and RV differed among viruses, as did relative contribution of each factor to overall variability. The marked variability seen in clinical quantitative viral load results is associated with multiple aspects of molecular testing design and performance. The reduction of such variability will require a multifaceted approach to improve the accuracy, reliability, and clinical utility of these important tests.

Age-related variations in hematologic and plasma biochemical test results in Beagles and Labrador Retrievers.

To investigate age-related variations in results of hematologic and plasma biochemical tests performed on dogs of 2 common breeds. Prospective cohort study. 34 Beagles and 44 Labrador Retrievers. Blood samples were collected throughout the dogs' lives; 589 samples were collected from the Beagles and 964 samples were collected from the Labrador Retrievers (age at the time of sample collection ranged from 22 days to 15 years). White blood cell and RBC counts; hemoglobin concentration; Hct; mean cell volume; mean cell hemoglobin concentration; alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase activities; and calcium, phosphorus, cholesterol, urea, protein, and albumin concentrations were measured. For all tests, there were significant effects of age on test results. There was a significant interaction between age and breed for all tests except hemoglobin, albumin, and phosphorus concentrations. Results suggested that there were age-related changes in hematologic and plasma biochemical test results in these 2 breeds of dogs. Changes were most evident during the first year of life, reflecting growth and maturation of the puppies. In some instances, values for puppies diverged markedly from those for adults, necessitating the use of age-specific reference ranges for the interpretation of clinical data.

Modelling pesticide residues on greasy wool: using organophosphate and synthetic pyrethroid survey data

Summary. Several surveys have examined the relationship between organophosphate and synthetic pyrethroid residues in wool and associated treatments. These have been combined and summarised using a model of on-farm survey data. The model estimated the amount of chemical taken up by the wool at application. This was based on experimental breakdown rates of these pesticides on wool determined in controlled trials. For about 10% of survey results the chemical measured on the wool did not match the chemical the producer said was applied. A further 5% of results were excluded because the amount of chemical detected on the wool was inconsistent with the stated time of treatment and shearing. With the remaining results there was a very high variation in residues resulting from the same (stated) treatment. It is clear that many producers do not know what chemicals they have used or how much they applied. The wide variation in results suggests that some producers may apply excessive amounts of pesticides while others use too little to have a useful effect. The model estimated the amount of pesticide taken up by the fleece using the residue left at shearing and the known breakdown rate for a given method and chemical group. When organophosphates were applied by dipping, the amount of chemical taken up by the fleece appeared to increase as the length of the wool increased. This was generally higher than would be anticipated from label dose rates but was consistent with the stripping characteristics of these chemicals. Therefore dipping as soon as possible after shearing left much lower residues (<10 mg/kg wool) than delayed treatment (often 10–30 mg/kg wool). In contrast the survey results suggest that the amount retained by sheep as a result of jetting decreased in longer wool. Jetting treatment rates appear to be lower than recommended, particularly for sheep with more than 6 months wool. Therefore jetting (as used by producers) left much lower residues in wool than dipping (with similar length wool) and was usually only above 10 mg/kg wool if carried out in the last 5 months before shearing, or if the same sheep received repeated treatments. The residue of synthetic pyrethroid retained in the fleece after dipping or long wool backliner application increased as the length of the wool increased at treatment, and appeared generally consistent with label recommendations. Current long wool backline products usually left residues of synthetic pyrethroid above 10 mg/kg on the wool. Short wool dipping left less than 10 mg/kg wool while off-shears backliners usually left average residue concentrations of about 2 mg/kg wool. Although the actual on-farm results vary 4-fold above and below the average, the model can be used to estimate the expected residue concentration and likely range of results from most standard on-farm organophosphate and synthetic pyrethroid treatments. This will allow improved provision of advice so that most producers can meet specified industry standards. It will allow wool buyers to estimate the risk of purchasing high residue wool based on producers’ statements about treatments applied.

SPATIAL AND TEMPORAL VARIATION IN RESULTS OF PURPLE URCHIN (STRONGYLOCENTROTUS PURPURATUS) TOXICITY TESTS WITH ZINC

SPATIAL AND TEMPORAL VARIATION IN RESULTS OF PURPLE URCHIN (STRONGYLOCENTROTUS PURPURATUS) TOXICITY TESTS WITH ZINC

Superhard Metals for Tool Facing

Abstract One of the greatest improvements in drilling equipment has been the developmentof hard facing metals which are welded by electricity or by acetylene to form afacing which protects the steel of the bit from abrasive wear. The maindesirable characteristics of hard facing metals are resistance to abrasivewear, resistance to shock and perfect bond with underlying metal. Resistance to abrasion offered by various metals shows many anomalies. Compounds containing carbon, silicon and boron are the most important hardsubstances. Carbon, as diamond, silicon carbide and especially the carbides ofiron, chromium and tungsten are the outstanding hard products in common use.Tungsten carbide is probably the most commonly used. It is made in the electricfurnace and it is important to get the right amount of carbon and the correctcrystalline structure in order to obtain the greatest hardness and greatestresistance to abrasion. It may be obtained in three main divisions: wrought, cast and casehardened. Insert hard metals are common. The method of application varies, but it isgenerally welded to the bit, placed in channels or in drilled holes and coveredwith a hard surfacing metal. Robinson has given a very complete article on the use of inserts. Gregg and Kiittner has discussed themetallography of tungsten carbides and given a good bibliography of thesubject. The time and expense of large-scale testing, together with variations inresults, led to the development of a laboratory testing machine for determiningthe abrasive-resisting qualities of different metals.