Integrated Thermal Energy Storage for Cooling Applications

Many commercial and industrial facilities are cooled using vapor compression cycles (VCC). The performance of such systems degrades with high outdoor temperatures causing high peak electric demand increase, reduced efficiency and lower cooling capacity. An Integrated Thermal Energy Storage System (ITESS) utilizing chilled water provides additional subcooling for a VCC condenser, thereby increasing the capacity of the entire system and providing significant reductions in electric demand and consumption. The ITESS uses a dedicated chiller to cool a thermal storage tank, typically at night when electricity demand and rates may be lower. This thermal reservoir is used during the following day to sub-cool refrigerant leaving the condenser. This additional cooling increases the overall cooling capacity of the chiller without increasing the electrical demand. The following paper outlines the results of a demonstration of the ITESS at an industrial facility in Syracuse, NY. The existing 176-ton chiller, which provides cooling for air conditioning a laboratory space and chilled water for compressor testing, was retrofitted with a 33-ton supplemental chiller, 10,000-gallon water tank, four sub-coolers, and two sub-cooler pumps. The ITESS was instrumented with a number of sensors to measure critical parameters to assess its performance. The test results showed that the cooling capacity of the existing chiller increased by 2.2% - 34.2%, depending on operating conditions, with the addition of subcooling. The ITESS increased existing chiller efficiency between 0.6% - 28.5% and has the potential to reduce power demand by 0.7%-34.3%. Total energy consumption for the system was essentially unchanged, increasing on average by approximately 0.05%, well within the margin of error

Competition In The eLearning Industry: A Case Study

This paper highlights the structural attributes of the eLearning Industry.  The case presents details regarding the evolution of the eLearning market and provides the opportunity for students of strategic management to build critical industry analytical skills by applying a variety of techniques highlighted in the accompanying case teaching note.  To obtain a copy of the teaching note, contact the corresponding author by email. The analytical techniques applied include the identification of the chief economic characteristics of the industry, Porter’s five force model of competition, the impact of driving forces on industry structure, and the identification of necessary competitive capabilities (success factors) for success in the eLearning industry

Noble Systems Inc.: Inside The Mind Of An Entrepreneur

This case illustrates the challenges faced by typical start-up businesses. The company has never earned a profit. Losses are being covered by cash infusions from angel investors. While significant business opportunities are present, the company doesnt have the money to pursue them all. Essentially, the case involves problems of growth, vision, potential, and management. The problems illustrated in the case can be analyzed using theories and approaches such as: SWOT analysis, financial analysis, business valuation, strategic human resource management, and strategic marketing/management. The case and Instructors Manual were written for undergraduate or MBA courses in strategic management. They can also be used in an entrepreneurship course if the instructor wishes to have a case that illustrates the strategic challenges associated with the decision whether to stay small and within the abilities of the founders, or to grow beyond their capabilities

Genetic Population Structure of Mule Deer Odocoileus Hemionus Across Montana

We conducted a genetic assessment of mule deer (Odocoileus hemionus) population structure across Montana in an effort to understand dispersal routes across the landscape. To assess genetic structure we genotyped 14 microsatellite loci in 359 individuals sampled primarily within Montana. Smaller samples were included from Wyoming, Colorado and Utah in order to provide a regional context for the levels of population structure observed within Montana. Additionally, we sequenced the control region of the mitochondrial genome of 76 individuals subsampled from our original samples across Montana. To avoid potential influences of a priori population designations, individual based analyses were used to test relatedness across the landscape. Weak isolation by distance characterized mule deer individuals across this region. In addition, we did not detect any evidence of spatial autocorrelation in discrete distance classes as small as 10 km. Female mule deer had higher average individual pairwise genetic distances than males, indicating the presence of a contemporary male bias in dispersal rates. Mitochondrial DNA indicated the potential for either reduced overall or female-specific dispersal between a subset of the sampling regions within Montana. Finally, we were unable to detect a genetic signature of past translocations of mule deer across Montana. Taken together these results indicate that within this landscape mule deer populations are characterized by high levels of connectivity and experience few, if any, barriers to dispersal

Deployment of Image Analysis Algorithms under Prevalence Shifts

Domain gaps are among the most relevant roadblocks in the clinical translation of machine learning (ML)-based solutions for medical image analysis. While current research focuses on new training paradigms and network architectures, little attention is given to the specific effect of prevalence shifts on an algorithm deployed in practice. Such discrepancies between class frequencies in the data used for a method's development/validation and that in its deployment environment(s) are of great importance, for example in the context of artificial intelligence (AI) democratization, as disease prevalences may vary widely across time and location. Our contribution is twofold. First, we empirically demonstrate the potentially severe consequences of missing prevalence handling by analyzing (i) the extent of miscalibration, (ii) the deviation of the decision threshold from the optimum, and (iii) the ability of validation metrics to reflect neural network performance on the deployment population as a function of the discrepancy between development and deployment prevalence. Second, we propose a workflow for prevalence-aware image classification that uses estimated deployment prevalences to adjust a trained classifier to a new environment, without requiring additional annotated deployment data. Comprehensive experiments based on a diverse set of 30 medical classification tasks showcase the benefit of the proposed workflow in generating better classifier decisions and more reliable performance estimates compared to current practice

Heterocyclic dithiocarbazate iron chelators: Fe coordination chemistry and biological activity

The iron coordination and biological chemistry of a series of heterocyclic dithiocarbazate Schiff base ligands is reported with regard to their activity as Fe chelators for the treatment of Fe overload and also cancer. The ligands are analogous to tridentate heterocyclic hydrazone and thiosemicarbazone chelators we have studied previously which bear NNO and NNS donor sets. The dithiocarbazate Schiff base ligands in this work also are NNS chelators and form stable low spin ferric and ferrous complexes and both have been isolated. In addition an unusual hydroxylated ligand derivative has been identified via an Fe-induced oxidation reaction. X-ray crystallographic and spectroscopic characterisation of these complexes has been carried out and also the electrochemical properties have been investigated. All Fe complexes exhibit totally reversible Fe couples in mixed aqueous solvents at potentials higher than found in analogous thiosemicarbazone Fe complexes. The ability of the dithiocarbazate Schiff base ligands to mobilise Fe from cells and also to prevent Fe uptake from transferrin was examined and all ligands were effective in chelating intracellular Fe relative to known controls such as the clinically important Fe chelator desferrioxamine. The Schiff base ligands derived from 2-pyridinecarbaldehyde were non-toxic to SK-N-MC neuroepithelioma (cancer) cells but those derived from the ketones 2-acetylpyridine and di-2-pyridyl ketone exhibited significant antiproliferative activity

Identification of 24 new microsatellite loci in the sweat bee Lasioglossum malachurum (Hymenoptera: Halictidae)

OBJECTIVE: The objective here is to identify highly polymorphic microsatellite loci for the Palaearctic sweat bee Lasioglossum malachurum. Sweat bees (Hymenoptera: Halictidae) are widespread pollinators that exhibit an unusually large range of social behaviours from non-social, where each female nests alone, to eusocial, where a single queen reproduces while the other members of the colony help to rear her offspring. They thus represent excellent models for understanding social evolution. RESULTS: 24 new microsatellite loci were successfully optimized. When amplified across 23-40 unrelated females, the number of alleles per locus ranged from 3 to 17 and the observed heterozygosities 0.45 to 0.95. Only one locus showed evidence of significant deviation from Hardy-Weinberg equilibrium. No evidence of linkage disequilibrium was found. These 24 loci will enable researchers to gain greater understanding of colony relationships within this species, an important model for the study of eusociality. Furthermore, 22 of the same loci were also successfully amplified in L. calceatum, suggesting that these loci may be useful for investigating the ecology and evolution of sweat bees in general

Constraints from Precision Electroweak Data on Leptoquarks and Bileptons

Explicit expressions are derived for the oblique parameters $S$ and $T$ in certain extensions of the standard model. In particular, we consider leptoquarks and bileptons, and find phenomenological constraints on their allowed masses. Leptoquarks suggested by the neutral and charged current anomalies at HERA can give improved agreement with both $S$ and $T$. If bileptons are the only new states, the singly-charged one must be heavier than the directly-established lower limit. Finally, we study SU(15) grand unification and show that there are regions of parameter space where the theory is compatible with experimental data.Comment: 25 pages LaTeX including 7 figures. With improved comparison to experimental data and other update

Super-heavy fermion material as metallic refrigerant for adiabatic demagnetization cooling

Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, as the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with $^3$He gas are widely used for cooling below 1 Kelvin. However, usage of the gas is being increasingly difficult due to the current world-wide shortage. Therefore, it is important to consider alternative methods of refrigeration. Here, we show that a new type of refrigerant, super-heavy electron metal, YbCo$_2$Zn$_{20}$, can be used for adiabatic demagnetization refrigeration, which does not require 3He gas. A number of advantages includes much better metallic thermal conductivity compared to the conventional insulating refrigerants. We also demonstrate that the cooling performance is optimized in Yb$_{1-x}$Sc$_x$Co$_2$Zn$_{20}$ by partial Sc substitution with $x\sim$0.19. The substitution induces chemical pressure which drives the materials close to a zero-field quantum critical point. This leads to an additional enhancement of the magnetocaloric effect in low fields and low temperatures enabling final temperatures well below 100 mK. Such performance has up to now been restricted to insulators. Since nearly a century the same principle of using local magnetic moments has been applied for adiabatic demagnetization cooling. This study opens new possibilities of using itinerant magnetic moments for the cryogen-free refrigeration

Hydrazone chelators for the treatment of iron overload disorders: iron coordination chemistry and biological activity

The potentially tridentate ligand 2-pyridinecarbaldehyde isonicotinoyl hydrazone (HPCIH) and its analogues are an emerging class of orally effective Fe chelators that show great promise for the treatment of Fe overload diseases. Herein, we present an extensive study of the Fe coordination chemistry of the HPCIH analogues including the first crystallographically characterised Fe-II complex of these chelators. Unlike most other clinically effective Fe chelators, the HPCIH analogues bind Fe-II and not F-III. In fact, these chelators form low-spin bis-ligand F-II complexes, although NMR suggests that the complexes are close to the high-spin/low-spin crossover. All the Fe complexes show a high potential Fe-III/(II) redox couple (> 500 mV vs. NHE) and cyclic voltammetry in aqueous or mixed aqueous/organic solvents is irreversible as a consequence of a rapid hydration reaction that occurs upon oxidation. A number of the HPCIH analogues show high activity at inducing Fe efflux from cells and also at preventing Fe uptake by cells from the serum Fe transport protein transferrin. As a class of ligands, these chelators are more effective at reducing Fe uptake from transferrin than inducing Fe mobilisation from cells. This may be related to their ability to intercept Fe-II after its release from transferrin within the cell. Our studies indicate that their Fe chelation efficacy is due, at least in part, to the fact that these ligands and their Fe-II complexes are neutral at physiological pH (7.4) and sufficiently lipophilic to permeate cell membranes