Synthesis of Multifunctional Polyethers: Anionic Ring-Opening Polymerization of Functional Epoxide Monomers

Department of ChemistryPolyethers, such as poly(ethylene glycol) (PEG), have been widely used for a variety of applications, owing to their high water solubility, superior biocompatibility, low toxicity, and flexible backbone. However, PEG possesses only two hydroxyl groups at both ends of the polymer chain, and this limits its functionalization. In this regard, the design and synthesis of functional epoxide monomers must be investigated for the preparation of various multifunctional polyethers, which have the potential for broad applications. This thesis describes the design and synthesis of functional epoxide monomers, followed by the synthesis of multifunctional polyethers using these monomers. Chapter 1 covers the general introduction and background of PEG and its derivatives, as well as the methods for further modification of polymers. The synthesis of thermoresponsive PEG-based functional polymers containing pendant amine groups is described in Chapter 2. Chapter 3 presents a one-pot synthesis of primary amine-containing hyperbranched polyglycerols (PGs) using a newly designed amino glycidyl ether monomer. Chapter 4 describes a series of novel azidoalkyl glycidyl ethers as universal monomers for the synthesis of azide-functional polyethers. Post-polymerization modification of the polymer through Cu-catalyzed azide-alkyne cycloaddition (CuAAC) and Staudinger reduction is demonstrated to propose the versatility of azide-functional polymers. Thus, this method acts as a new platform for the preparation of functional polyethers.clos

Some Remarks on Kim-dividing in NATP Theories

In this note, we prove that Kim-dividing over models is always witnessed by a coheir Morley sequence in NATP theories. Following the strategy of Chernikov and Kaplan [8], we obtain some corollaries which hold in NATP theories. Namely, (i) if a formula Kim-forks over a model, then it quasi-divides over the same model, (ii) for any tuple of parameters $b$ and a model $M$, there exists a global coheir $p$ containing $\text{tp}(b/M)$ such that B\ind_M^Kb' for all $b'\models p|_{MB}$. We also show that in NATP theories, condition (ii) above is a necessary condition for being a witness coheir, assuming the existence of witnesses (see Definition 4.1 in this note). That is, if we assume that a witness coheir for Kim-dividing always exists over any given model, then a coheir $p\supseteq \text{tp}(a/M)$ must satisfy (ii) whenever it is a witness for Kim-dividing of $a$ over a model $M$. We also give a sufficient condition for the existence of witness coheirs in terms of pre-independence relations. At the end of the paper, we leave a short remark on Mutchnik's recent work [16]. We point out that in $\omega$-NDCTP$_2$ theories, a subclass of the class of NATP theories, Kim-forking and Kim-dividing are equivalent over models, where Kim-dividing is defined with respect to invariant Morley sequences, instead of coheir Morley sequences as in [16]

Development of a Model to Predict the Likelihood of Complaints due to Assorted Tone-in-Noise Combinations

This paper develops a model to predict if listeners would be likely to complain due to annoyance when exposed to a certain noise signal with a prominent tone, such as those commonly produced by heating, ventilation, and air-conditioning systems. Twenty participants completed digit span tasks while exposed in a controlled lab to noise signals with differing levels of tones, ranging from 125 to 1000 Hz, and overall loudness. After completing the digit span tasks under each noise signal, from which task accuracy and speed of completion were captured, subjects were asked to rate level of annoyance and indicate the likelihood of complaining about the noise. Results show that greater tonality in noise has statistically significant effects on task performance by increasing the time it takes for participants to complete the digit span task; no statistically significant effects were found on task accuracy. A logistic regression model was developed to relate the subjective annoyance responses to two noise metrics, the stationary Loudness and Tonal Audibility, selected for the model due to high correlations with annoyance responses. The percentage of complaints model showed better performance and reliability over the percentage of highly annoyed or annoyed

Relationships of self-identified cold tolerance and cold-induced vasodilatation in the finger

Thermal environments in daily life, such as occupational cold exposure and the use of heating facilities and warm clothing, affect acclimatization to both cold and heat. Also, cold tolerance can be cognized by self-identified evaluation. Thermal life-style during daily life might be one of the factors which affect cold-induced vasodilatation (CIVD) when different degrees of thermal stimuli are considered. Therefore, this study investigated whether or not CIVD response is related to self-identified cold and heat tolerances which is attributable to thermal life-style

Preservation of NATP

We prove several preservation theorems for NATP and furnish several examples of NATP. First, we prove preservation of NATP for the parametrization and sum of the theories of Fra\"{i}ss\'{e} limits of Fra\"{i}ss\'{e} classes satisfying strong amalgamation property. Second, we prove preservation of NATP for two kinds of dense/co-dense expansions, that is, the theories of lovely pairs and of H-structures for geometric theories and dense/co-dense expansion on vector spaces. Third, we prove preservation of NATP for the generic predicate expansion and the pair of an algebraically closed field and its distinguished subfield; for the latter, not only NATP, but also preservations of NTP$_1$ and NTP$_2$ are considered. Fourth, we present some proper examples of NATP using the results proved in this paper. Most of all, we show that the model companion of the theory of algebraically closed fields with circular orders (ACFO) is NATP.Comment: 35 page

Determining Annoyance Thresholds of Tones in Noise

Building services equipment often produces noise signatures with significant tones in them that can lead to complaints in the built environment. Previous studies have investigated prominence levels of assorted tonal frequencies, but it is still unclear what prominence of the tones across varying tonal frequencies can lead to human annoyance. This project seeks to apply two different methods towards defining annoyance thresholds of tones in noise at two tonal frequencies: 125 Hz and 500 Hz. In the first, subjects are asked to perform a task, while exposed to ten minutes of a broadband noise spectrum with a specific level of tonal prominence. They are subsequently asked to rate their annoyance to that noise condition. Five prominence levels of each of the two tones are tested above two different background noise levels, for a total of 20 test trials. In the second methodology, subjects listen to each of the two tonal frequencies at a predetermined level above each of the two background noise levels, and then adjust the level of the tone up or down until it becomes just annoying. The strengths, weaknesses, and results obtained for the annoyance thresholds of tones in noise from each of these methods are compared

Cold adaptation, aging, and Korean women divers haenyeo

Abbreviations BAT: Brown adipose tissue; BMR: Basal metabolic rate; CIVD: Cold-induced vasodilation; NST: Non-shivering thermogenesis; Tsk: Skin temperature; Tre: Rectal temperature; Tmax: Maximum temperature; Tmean: Average temperature during immersion; Tmin: Minimum temperature; Trecovery: Temperature in recoveryAbstract Background We have been studying the thermoregulatory responses of Korean breath-hold women divers, called haenyeo, in terms of aging and cold adaptation. During the 1960s to the 1980s, haenyeos received attention from environmental physiologists due to their unique ability to endure cold water while wearing only a thin cotton bathing suit. However, their overall cold-adaptive traits have disappeared since they began to wear wetsuits and research has waned since the 1980s. For social and economic reasons, the number of haenyeos rapidly decreased to 4005 in 2015 from 14,143 in 1970 and the average age of haenyeos is about 75 years old at present. Methods For the past several years, we revisited and explored older haenyeos in terms of environmental physiology, beginning with questionnaire and field studies and later advancing to thermal tolerance tests in conjunction with cutaneous thermal threshold tests in a climate chamber. As control group counterparts, older non-diving females and young non-diving females were compared with older haenyeos in the controlled experiments. Results Our findings were that older haenyeos still retain local cold tolerance on the extremities despite their aging. Finger cold tests supported more superior local cold tolerance for older haenyeos than for older non-diving females. However, thermal perception in cold reflected aging effects rather than local cold acclimatization. An interesting finding was the possibility of positive cross-adaptation which might be supported by greater heat tolerance and cutaneous warm perception thresholds of older haenyeos who adapted to cold water. Conclusions It was known that cold-adaptive traits of haenyeos disappeared, but we confirmed that cold-adaptive traits are still retained on the face and hands which could be interpreted by a mode switch to local adaptation from the overall adaptation to cold. Further studies on cross-adaptation between chronic cold stress and heat tolerance are needed.This study was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No.2014R1A2A2A03006522

Thermal Effects of Microwave Reduced-Graphene-Oxide Coated Polyester Fabric on a Simulated Human Skin in Cool and Neutral Air Temperatures

Batteryless wearable technology has wide applications. In particular, human body surface temperature controlling fabrics can help regulate skin temperature in heat or cold. This study investigated surface temperature distribution of the fabrics coated with reduced graphene oxide (rGO) on simulated human body skin conditions at 18 degrees C (cool) and 27 degrees C (neutral) ambient air temperatures. Polyester fabrics were spin-coated with a graphene-oxide (GO) solution of 0.2 wt%. Preparation of rGO was processed by using a microwave oven (MW-rGO). Non-treated fabric (CON) was compared to GO and MW-rGO. The surface temperature of a hot plate was maintained at 35 degrees C or 40 degrees C. The test fabrics were put on the heated hot plate or non-heated-outer portions of the hot plate. Surface temperatures of MW-rGO on the heated hot plate at an air temperature of 18 degrees C (cool) were higher than those of non-treated fabric (CON) under the same conditions (p < 0.01). No effects from the graphene treatment were found on non-heated portions of the graphene oxide fabric (GO) or the reduced graphene oxide fabric (MW-rGO). On the non-heated portions, surface temperatures were higher at the location closer to the hot plate compared to the location farther from the hot plate (p < 0.05). These results partially represent thermal effects of MW-rGO under a specific environment and heat source. Our findings enable an application of reduced graphene oxide to body temperature regulating clothing.

Evaluation of the uniformity of sound-masking systems in an open-plan office

Many open-plan offices adopt an electronic sound masking system in order to reduce distraction from background noises, primarily intruding speech. Sound masking systems should uniformly generate a masking sound over the entire office area to homogenize the speech privacy whilst minimising occupant perception of the masking sound. This study evaluates the spatial uniformity of the masking sound field in an example open-plan office, where the masking system was set up to represent supposedly optimal installation conditions; 1-speaker zones, individually-calibration of each zone to match the specified curve precisely, and smaller zones than typically specified. Sound level measurements performed as per ASTM E1573-18 were made at each workstation, as well as every 0.6 m across the office, for a total of 117 measurements. Measurement results show that tolerance of ± 0.5 dB for the overall A-weighted level is only achievable at 61% of measurement locations, whilst ± 1 dB is achievable at 99% of locations. For one-third-octave band sound pressure levels between 250 Hz to 4 kHz, ± 2 dB is achieved only 55% of the time, and tolerance of ± 3.5 dB is required to achieve 95% compliance with the specified curve. By using calibrated computer simulations, the study also examined parameters that can influence spatial uniformity in open-plan offices. It was found that the number of sound masking loudspeakers, partition height, and the scattering and absorption coefficient of the ceiling all affect the uniformity of the masking sound. Speech intelligibility was assessed by calculating the Articulation Index (AI) to determine an acceptable tolerance for masking sound variation. Increasing the number of loudspeakers was the most effective way to improve the uniformity of the masking sound. The AI results suggest ±2 dB, when including octave band sound pressure levels, is a minimum required tolerance for a sound masking sound field in an open office to provide AI values within ±0.1 of the targeted value across the office area

Design of exceptionally strong and conductive Cu alloys beyond the conventional speculation via the interfacial energy-controlled dispersion of gamma-Al2O3 nanoparticles

The development of Cu-based alloys with high-mechanical properties (strength, ductility) and electrical conductivity plays a key role over a wide range of industrial applications. Successful design of the materials, however, has been rare due to the improvement of mutually exclusive properties as conventionally speculated. In this paper, we demonstrate that these contradictory material properties can be improved simultaneously if the interfacial energies of heterogeneous interfaces are carefully controlled. We uniformly disperse γ-Al2O3 nanoparticles over Cu matrix, and then we controlled atomic level morphology of the interface γ-Al2O3 //Cu by adding Ti solutes. It is shown that the Ti dramatically drives the interfacial phase transformation from very irregular to homogeneous spherical morphologies resulting in substantial enhancement of the mechanical property of Cu matrix. Furthermore, the Ti removes impurities (O and Al) in the Cu matrix by forming oxides leading to recovery of the electrical conductivity of pure Cu. We validate experimental results using TEM and EDX combined with first-principles density functional theory (DFT) calculations, which all consistently poise that our materials are suitable for industrial applications.1