Adverse Effects Of Temperature Research Articles

Effect of dissolved solids on reuse of produced water at high temperature in hydraulic fracturing jobs

Economic production from tight sand gas reservoirs usually involves multistage hydraulic fracturing. High costs of water acquisition and waste water disposal, and the lack of available water resources near operation sites, make the reuse of produced water an unavoidable option. However, recycling produced water in hydraulic fracturing jobs result in low quality fracturing fluids, which usually have high levels of hardness and salinity. This is especially true for flowback fluids, which contain high polymer loading. The viscosity and rheological properties of fracturing fluids significantly affect leak-off rate, proppant placement, length and width of fractures, fracture conductivity, and consequently, the success of the treatment. The objective of this study is to determine the acceptable dissolved solid contents for flowback fluids to prepare fracturing fluids.Analyses of 36 flowback fluid samples from the West Texas region were collected, and experimental studies were conducted on the analysis of the dissolved solids of produced water, which affect the application of flowback fluids and the capability of prepared fluids in proppant transport and handling. A high-pH borate crosslinked guar-based polymer was selected to determine the ranges of acceptable salt contents. Dynamic viscosity and rheological properties tests, static proppant settling, and small-amplitude oscillation rheology were the methods used to evaluate prepared samples at low, medium, and high temperatures up to 305 °F (152 °C).Some divalent cations such as calcium and magnesium have negative effects on the prepared polymers. Magnesium is the controlling ion, and approximately 30% of flowback fluids must be treated to meet the maximum acceptable concentration criterion. While monovalent cations such as sodium and potassium were tolerable at higher concentrations and the potassium contents in almost all flowback fluids met the determined acceptable value, more than 40% of samples required treatment for high sodium ion concentrations. Although the presence of other ions such as iron shows no significant variation in fracturing fluid properties, they can affect treatment in special cases. Adjusting the concentrations of the polymer, buffer, and crosslinker can minimize the adverse effects of temperature and salts. The fluids prepared with the determined ranges of dissolved solids showed reasonable thermal stability and proppant transport characteristics. This paper introduces the practical operating range for produced water composition and defines the ions that can adversely impact borate-crosslinked fracturing fluid characteristics at different temperatures.

Reducing Downtime by Proper Motor Lubrication

Over two-thirds of motor malfunctions, resulting in a trip to the electric motor service center for repair or reconditioning, can be attributed to bearing issues. This paper addresses ways to mitigate the damage to the bearings and maximize the life by utilizing a proper lubrication regimen. Various types of bearings for horizontal and vertical applications will be covered. The emphasis will be on their individual lubrication requirements relative to bearing type, load, speed, and environment. The adverse effects of temperature, contamination, and time will be discussed along with tips to mitigate those effects. Grease compatibility problems will be covered.

Acute and Prolonged Adverse Effects of Temperature on Mortality from Cardiovascular Diseases

BackgroundCardiovascular diseases are the leading causes of death worldwide, especially for developed countries. Elevated mortality from cardiovascular diseases has been shown related to extreme temperature. We thus assessed the risk of mortality from cerebrovascular diseases, heart diseases, and ischemic heart disease (IHD) in relation to temperature profiles in four subtropical metropolitans (Taipei, Taichung, Tainan, and Kaohsiung) from 1994 to 2007 in Taiwan.MethodsDistributed lag non-linear models were applied to estimate the cumulative relative risks (RRs) with confidence intervals of cause-specific mortality associated with daily temperature from lag 0 to 20 days, and specific effect of extreme temperature episodes with PM10, NOx, and O3, and other potential confounders controlled. Estimates for cause-specific mortalities were then pooled by random-effect meta-analysis.ResultsComparing to centered temperature at 27°C, the cumulative 4-day (lag 0 to 3) risk of mortality was significantly elevated at 31°C for cerebrovascular diseases (RR = 1.14; 95% CI: 1.00, 1.31) and heart diseases (RR = 1.22; 95% CI: 1.02, 1.46) , but not for IHD (RR = 1.09; 95% CI: 0.99, 1.21). To the other extreme, at 15°C, the cumulative 21-day (lag 0 to 20) risk of mortality were also remarkably increased for cerebrovascular diseases, heart diseases, and IHD (RRs = 1.48 with 95% CI: 1.04, 2.12, 2.04 with 95% CI: 1.61, 2.58, and 1.62 with 95% CI: 1.30, 2.01, respectively). Mortality risks for cardiovascular diseases were generally highest on the present day (lag 0) of extreme heat. No particular finding was detected on prolonged extreme temperature event by pooling estimations for cause-specific mortality.ConclusionsLow temperature was associated with greater risk of mortality from cardiovascular diseases in comparison with that of high temperature. Adverse effects of extreme temperatures are acute at the beginning of exposure.

Red light-excitable dual lifetime referenced optical pH sensors with intrinsic temperature compensation

Red light-excitable pH sensing materials are manufactured which rely on the use of a fluorescent seminaphthorhodafluor indicator and a luminescent inorganic phosphor as a reference. The phosphors, chromium(III)-activated lanthanide aluminium borates, benefit from chemical and photochemical robustness and are not affected by oxygen. Particularly, a dual lifetime referenced sensing material relies on Cr(III)-activated gadolinium aluminium borate which has low temperature dependence of the decay time. The second material is based on highly temperature-sensitive Cr(III)-doped yttrium aluminium borate and enables dual sensing of pH and temperature. Here, the phosphor simultaneously acts as a temperature probe and as a reference for the pH indicator. The adverse effects of temperature on the properties of the pH indicator are compensated for. The dynamic range of the sensors is optimized by varying the ratio of the components which makes the materials suitable for physiological measurements and for marine applications. The rather poor chemical and photochemical stability of the pH indicator at room temperature should be considered if prolonged measurements are performed.

Elevated Temperature After Hypoxic-Ischemic Encephalopathy: Risk Factor for Adverse Outcomes

The goal was to determine whether the risk of death or moderate/severe disability in term infants with hypoxic-ischemic encephalopathy increases with relatively high esophageal or skin temperature occurring between 6 and 78 hours after birth. This was an observational secondary study within the National Institute of Child Health and Human Development Neonatal Research Network randomized trial comparing whole-body cooling and usual care (control) for term infants with hypoxic-ischemic encephalopathy. Esophageal and skin temperatures were recorded serially for 72 hours. Each infant's temperatures for each site were rank ordered. The high temperature was defined for each infant as the mean of all temperature measurements in the upper quartile. The low temperature was similarly defined as the mean of the lower quartile. Outcomes were related to temperatures in 3 logistic regression analyses for the high, median, and low temperatures at each temperature site for each group, with adjustment for the level of encephalopathy, gender, gestational age, and race. In control infants, the mean esophageal temperature was 37.2 +/- 0.7 degrees C over the 72-hour period, and 63%, 22%, and 8% of all temperatures were >37 degrees C, >37.5 degrees C, and >38 degrees C, respectively. The mean skin temperature was 36.5 +/- 0.8 degrees C, and 12%, 5%, and 2% of all temperatures were >37 degrees C, >37.5 degrees C, and >38 degrees C, respectively. The odds of death or disability were increased 3.6-4 fold for each 1 degrees C increase in the highest quartile of skin or esophageal temperatures. There were no associations between temperatures and outcomes in the cooling-treated group. Relatively high temperatures during usual care after hypoxia-ischemia were associated with increased risk of adverse outcomes. The results may reflect underlying brain injury and/or adverse effects of temperature on outcomes.

Issues involved in a Martian sample return: Integrity preservation and the Curation and Analysis Planning Team for Extraterrestrial Materials (CAPTEM) position

Returning geological samples from Mars is the next logical step as part of an integrated exploration program and is the critical subsequent stage in the search for evidence of life on the red planet. Analysis of such samples on Earth will generally produce data of superior accuracy and precision than can be accomplished in situ on the Martian surface, and such data will be invaluable in providing ground truth for remotely sensed observations. However, obtaining meaningful data requires that the samples returned to Earth suffer little (or preferably no) compositional or morphological changes during collection on Mars, transit to Earth, entry into Earth's atmosphere, impact on the surface, and long‐term curation. This paper presents recommendations from NASA's committee for Curation and Analysis Planning Team for Extraterrestrial Materials (CAPTEM) for preserving the integrity of Martian samples during a return mission. Potential contaminants include dead bacteria on the outbound spacecraft and materials that come into contact with the samples during collection and storage. Therefore it is recommended that the spacecraft be sterilized and cleaned at least to Pathfinder standards, with the components that interact with the samples having a higher degree of cleanliness. Furthermore, it is recommended that only pure, homogeneous materials should be used for components that come into contact with the samples. The adverse effects of temperature on the samples are explored, and it is demonstrated that heat sterilization or undue temperature increases in transit or reentry have the potential to destroy important mineralogical and geochemical information. Concomitant with this will be degassing of the samples and stable isotopic fractionation. Therefore it is recommended that samples be kept at 240 K or below during transit, reentry, and curation. It is further recommended that heat sterilization not be used, except in extreme circumstances, and other sterilization techniques, such as radiation, be explored. While the purpose of this paper is not to design a sample return mission, the recommendations presented here are intended to act as guidelines for returning Martian samples in their pristine state. In essence, any procedure or piece of equipment that has the potential to compromise the pristinity of Martian samples during the collection, transportation, or curation needs to be fully evaluated by a scientific committee with the requisite expertise prior to implementation. CAPTEM is willing to serve in such a capacity if requested by NASA.

The Pigeonpea-RhizobiumSymbiosis as Affected by High Root Temperture: Effect on Nodule Formation

ABSTRACT The effect of elevated temperature on root hair formation, adsorption of rhizobia, and nodulation of pigeonpea was studied.Nodulation was adversely affected at both 28 °C and 37 °C, and the effect was more pronounced during the first 3 d of noduleformation. Temperatures above 32 °C resulted in the reduction or even complete absence of root hairs. The root hairs formed atelevated temperatures were spheroid and stunted in growth. The number of loosely and firmly adsorbed cells of Bradyrhizobiumspp. (Cajanus) strain CCIO2l on pigeonpea roots were reduced to 49% and 38%, respectively, at 37°C.Key words: Pigeonpea, Bradyrhizobium spp. (Cajanus), high root temperature, root hairs, adsorpti INTRODUCTION Pigeonpea (Cajanus cajan L. Millsp) is one of the majorgrain legumes grown in the Indian sub-continent. How-ever, the crop nodulates very poorly, especially in northernIndia (Khurana and Dudeja, 1981). Poor nodulation ofpigeonpea can probably be ascribed to the high tempera-ture (nearly 50 DC in upper 5.0 cm soil layer) prevailing inthis region during planting season of the crop. Adverseeffects of temperature on nodule formation and develop-ment have been very well documented in clover (Pankhurstand Gibson, 1973); pea (Frings, 1976); Lotus and Stylo-santhes (Rao, 1977) arid soybean (Munevar and Wollum,1981). The present investigation was undertaken to identifythe temperature-sensitive stage in nodulation of pigeonpeaand to find out the mechanism by which high temperatureaffects the sensitive stage.

Hermit crab fitness: The effect of shell condition and behavioral adaptations on environmental resistance

The degree of three behavioral responses (aggregation with other individuals, movement towards shaded locations and shell exiting) shown by the coexisting hermit crabs, Pagurus samuelis (Stimpson), P. hirsutiusculus venturensis (Coffin), P. granosimanus (Stimpson) and P. hemphilli (Benedict), when aerially exposed, corresponded with their pattern of intertidal vertical zonation. The highest occurring species, P. samuelis, exhibited significantly greater tendencies to aggregate with other individuals and to seek refuge in shaded locations and usually remained within their shells when exposed to the combined stresses of temperature and desiccation. P. hirsutiusculus and P. granosimanus, primarily mid- to low-intertidal species, displayed these responses only occasionally while P. hemphilli, a lowintertidal and shallow-subtidal species, showed significantly lower clustering, shade attraction, and shell abandonment responses. Comparison of larger and smaller P. samuelis revealed no significant behavioral differences. P. samuelis and P. granosimanus that occupied shells not allowing complete retraction were less resistant to the stresses of aerial exposure. Crabs inhabiting damaged shells with holes ( ≈ 5 mm diam.) in the whorls or spire did not experience decreased survival in comparison with that found in crabs occupying entire shells. These findings suggest an implication of shell optimality with environmental resistance that should be considered of potential importance in the evolution of complex communicative and aggressive behavior in intertidal hermit crabs. In addition, attraction to shaded areas and clustering are behavioral responses appropriate for avoiding or reducing the adverse effects of temperature and desiccation stresses. These responses may be important in facilitating the coexistence of these species although further investigation is needed to quantify the importance of such behavior to intertidal hermit crab populations. The significance of shell-exiting is not specifically known but survival of a shell-less crab is undoubtedly minimal.

Influence of temperatuer on the incorporation of palmitic acid-U-14C into rat testicular lipids.

Summary. Biosynthesis of protein in rat testes is known to have a temperature optimum at 32° C; the normal scrotal temperature. The incorporation of palmitic acid into lipids was examined for a temperature dependence. Testicular tissue was incubated for 2 hr with palmitic acid-U-14C at 28, 30, 32, 34 and 36° C. Lipids were extracted and lipid classes separated by thin-layer chromatography. Palmitic acid oxidation was measured. Most lipids incorporated palmitic acid with a positive temperature coefficient. The percentage increases in incorporation of fatty acid over the 8° C range were: free fatty acid (58), triglycerides (51), sterol esters (56), diglycerides (19), monoglycerides (marked decline), sterols (no change), phosphatidyl choline (66), lyso-phosphatidyl choline (36), cephalins (25). The percentage distribution of neutral lipid was free fatty acid (9), triglycerides (4), sterol esters (29), diglycerides (6), monoglycerides (6), sterols (25). The percentage distribution of phospholipid was: phosphatidyl choline (41), lyso-phosphatidyl choline (3), cephalin (44), sphingomyelin (4). Palmitic acid oxidation increased 13% over the 8° C range. It is concluded that lipid synthesis is not as sensitive to temperature change as protein synthesis. Adverse effects of temperature on lipids are probably a consequence of impaired protein metabolism.

A Transistor Univibrator with Stabilized Pulse Duration

The use of an elementary characterization of the transistor leads to a very simple model of the basic emitter-coupled univibrator, or monostable multivibrator. Based on this model calculations of waveforms exhibit a reasonable degree of accuracy. Furthermore, the simplicity of the model is conducive to a facile understanding of the operation of the circuit and its disadvantages. A method for circumventing the adverse effects of temperature upon the quasi-stable duration is readily deduced, and may be extended to permit an increase in quasi-stable duration without an increase in jitter. Experimental and calculated waveforms are given and experimental curves are given which indicate the effectiveness of the temperature stabilization.