Consequences Of Temperature Variation Research Articles

Semiconductor‐to‐Metal‐like Transition Behavior under Temperature Variation for Inkjet Printed PEDOT:PSS Tracks Embedded in Polymer

Herein, it is intended to show the effect of embedding an inkjet printed poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) track in an insulator polymer, impacting its electronic transition behavior, as a consequence of temperature variation. A transition from semiconductor‐to‐metal‐like behavior is observed, when the temperature is seen to exceed a certain value, which is of a nonchemical origin. Both the presented experimental and simulation results show how this transition really occurs. The proposed physical mechanism for explaining such a behavior is verified with good repeatability. The main conclusion indicates consideration of special precautions, while enclosing inkjet‐printed PEDOT:PSS‐based tracks or sensors operating under ambient conditions, along with fluctuations. This conclusion can potentially be applied to any other inkjet printed conductive organic polymer film embedded in an insulator that fulfills the conditions encountered in the experiments. The impact of this effect may be reduced and mitigated by using inkjet printing, in combination with other additive manufacturing technique. The results presented here are considered very important, as they lay the foundation for the correct compensation of the thermal drift of organic electronics‐based circuits.

Assessment of Sputtered Chromium Oxide-Nitride Coatings

Abstract The main purpose of this research work is to explore the formation of chromium oxide-nitride coatings by radio frequency (RF) magnetron sputtering using chromium as a target, oxygen and nitrogen as reactive gases, along with helium as an inert gas. The consequence of temperature variation on the formation of chromium oxide-nitride coatings and their properties is reported in this paper. The identification of respective oxide/nitride phases of chromium was done by X-ray diffraction. A wettability study of chromium oxide-nitride coatings was done using a contact angle–measuring system. Initially, at a lower deposition temperature of 200°C, the deposited films were amorphous. However, when the temperature was increased from 200°C to 600°C, the formation of crystalline films was observed, and its wettability behavior was transmuted from hydrophilic to hydrophobic. The influence of temperature variation on the tribological properties of mixed chromium oxide-nitride coatings is examined.

A numerical model of nonuniform solar cell stability

We model degradation in extended two-dimensional solar cells. The model couples electrical and thermal physics, so that voltage and temperature can vary over a device. Degradation is modeled phenomenologically, such that local open circuit voltage degradation is dependent on local temperature. Initial device nonuniformity is introduced with an initial spatial distribution of random shunt conductances. A comparison of pre- to post-stress performance shows variations, despite the deterministic nature of the degradation model, which is interpreted as a consequence of temperature variations.

Processed Dairy Beverages pH Evaluation: Consequences of Temperature Variation

This study assessed the pH from processed dairy beverages as well as eventual consequences deriving from different ingestion temperatures. 50 adults who accompanied children attended to at the Dentistry School were randomly selected and they answered a questionnaire on beverages. The beverages were divided into 4 groups: yogurt (GI) fermented milk (GII), chocolate-based products (GIII) and fermented dairy beverages (GIV). They were asked which type, flavor and temperature. The most popular beverages were selected, and these made up the sample. A pH meter Quimis 400A device was used to verify pH. The average pH from each beverage was calculated and submitted to statistical analysis (Variance and Tukey test with a 5% significance level). for groups I, II and III beverages, type x temperature interaction was significant, showing the pH averages were influenced by temperature variation. At iced temperatures, they presented lower pH values, which were considered statistically significant when compared to the values found for the same beverages at room temperature. All dairy beverages, with the exception of the chocolate-based type presented pH below critical level for enamel and present corrosive potential; as to ingestion temperature, iced temperature influenced pH reducing its values, in vitro.

Seismic implications of mantle wedge plumes

We use a coupled petrological–thermomechanical model to investigate the dynamical effects of metamorphic reactions and melting on the seismic structure of thermal–chemical plumes beneath volcanic arcs. Plume generation is driven by the subduction of buoyant crustal rocks and expulsion of aqueous slab fluids that causes hydration and partial melting of the mantle wedge. The model demonstrates two chemically distinct types of plumes. Unmixed plumes initiate from the melting front within the mantle that arises as a consequence of infiltration of slab-derived water-rich fluids, whereas mixed plumes initiate from the slab itself and entrain both slab- and mantle-derived magmas. Mixed plumes explain magmas such as adakites with crustal signatures, while primitive arc tholeiites are attributed to unmixed plumes. As a consequence of the interplay between water content and temperature both positive and negative seismic velocity anomalies are associated with the plumes. Positive anomalies are prevalent close to the slab due to the lowered temperatures associated with regions of cold plume initiation. Negative seismic anomalies develop at shallower depth due to the partially molten rocks that form plume heads. Flat lying partially molten regions that form beneath volcanic arcs as a consequence of cold wet plumes are manifest by >20% variations in the local Poisson ratio, as compared to variations of ∼2% expected as a consequence of temperature variation within the mantle wedge. In contrast to models that attribute a purely thermal origin for mantle wedge seismic anomalies, the petrological–thermomechanical model is able to explain the strong seismic velocity variations existing beneath volcanic arcs.

Nonstoichiometry and problems of prevention of polymorphic transformations in crystalline compounds

The effect of defects of the tungsten trioxide crystal lattice caused by disturbance of the stoichiometry on the polymorphic transformations arising as a consequence of temperature variations is considered. It is demonstrated that the introduction of a more electropositive metal in tungsten trioxide, which transforms this oxide into tungsten oxide bronze, suppresses the phenomenon of nonstoichiometry in oxygen, which creates conditions for stabilization of the polymorphic modifications in a wide temperature range.