HVAC Systems with Low Global Warming Potential Refrigerants: A Case Study

The objective of this case study is three-fold: (1) identify promising alternative refrigerants with lower global warming potential (GWP); (2) among those, select refrigerant(s) that could be “drop-in” replacements for R-410A and would not require significant system redesign or compressor changes — with the exception of minimal changes such as lubricating fluid and expansion valves; (3) evaluate the impact of another easy-to-implement option: replacing lower-efficiency, permanently split capacitor (PSC) condenser fans and evaporator blower motors with electronically commutated motors (ECM) for additional system efficiency improvements. This study leverages the steady-state heat pump design model (HPDM) developed by the Department of Energy (DOE) and the Oak Ridge National Laboratory (ORNL) to demonstrate three key findings: (1) two popular refrigerant replacement candidates with a GWP less than 750, R-32 and R-454B; both have system performance equal to or better than R-410A; (2) the lower-GWP refrigerant options with a GWP below 300 all underperform compared to R-410A; however, heat exchanger optimization may improve system performance; (3) using an ECM instead of a PSC evaporator blower motor increased system seasonal energy efficiency ratio (SEER) performance ~8% for all refrigerants evaluated

Asthma in the Disadvantaged: A Phenotype in Need of a Personalized, Multidisciplinary Approach to Therapy

Most patients with asthma can be managed with standardized, traditional therapies; however, 5–10% of patients suffer from disease that is difficult to control. Uncontrolled asthma disproportionally affects low income and racial minority patients. The disadvantaged asthma phenotype is defined by the presence of overlapping social, economic and environmental factors. These factors, such as environmental exposures in substandard housing or suboptimal adherence to controller therapy due to impaired health literacy are challenging to address in the clinic or inpatient setting. Personalized management of the disadvantaged asthma phenotype must target these interconnected factors through a multidisciplinary approach that includes longitudinal collaboration with community-based organizations, social workers and legal aid

Seeing in the Dark and Through Walls: Using IR Cameras in STEM Outreach

The recent introduction of affordable infrared (IR) cameras and IR imaging attachments for smartphones has provided a unique opportunity to enhance the education of K-12 students. We have acquired a number of different IR cameras and IR camera attachments and discuss the utilization of these devices in both a college course and in our STEM and STEAM outreach efforts. While our outreach efforts have placed us in a classroom for just an hour or two at a time, thanks to local IEEE Chapter support, we have placed IR cameras in these classrooms for several weeks at a time. This paper discusses the outreach efforts and the utilization of IR cameras by 5th grade elementary school students and their classroom teachers after our departure and the wild enthusiasm that this approach has generated. A comparison of the different IR systems is also made

Validation of a Load-Based Testing Method for Characterizing Residential Air-Conditioner Performance

Seasonal performance assessments of air-conditioning and heat-pump systems are typically carried out based on performance measurement of equipment in a test laboratory. The performance ratings that arise from these assessments are important in providing information to consumers, and in influencing policymakers to determine appropriate incentives for high-efficiency equipment in the marketplace. The current testing and rating approach for performance evaluation of residential air-conditioning and heat-pump systems is based on steady-state performance measurements, with a degradation coefficient to account for the cycling losses that occur during part-load operating conditions. However, this current methodology fails to appropriately characterize the true performance characteristics of these systems in the field, and as a consequence, SEER (seasonal energy efficiency ratio) improvements have not resulted in proportional savings in energy. As an alternative, a load-based testing methodology has been developed with the motivation of capturing realistic equipment performance in a laboratory setting while operating similar to field application conditions. In this approach, the equipment responds to a simulated virtual building load, and the system dynamic performance is measured with its integrated controls and thermostat. However, there is a lack of field-testing data to characterize how well the load-based testing approach captures equipment performance and dynamic behavior compared to a typical field application. To fill this gap, a 3-ton heat pump system was tested within the Residential Home Ecosystem at the Helix Innovation Center where a 2-story house is located within an environmental chamber that can vary external ambient temperature and humidity conditions. During tests, the house was subjected to cooling loads resulting from different outdoor temperature conditions, and its air conditioning system responded accordingly. Similar cooling equipment was also tested within psychrometric chambers at the Ray W. Herrick Laboratories using the load-based testing methodology. A comparison of the test equipment performance and its dynamic behavior in cooling mode between testing performed at the Helix Center and at the Herrick Laboratories is presented in this paper

A Plasmid-Transposon Hybrid Mutagenesis System Effective in a Broad Range of Enterobacteria.

Random transposon mutagenesis is a powerful technique used to generate libraries of genetic insertions in many different bacterial strains. Here we develop a system facilitating random transposon mutagenesis in a range of different Gram-negative bacterial strains, including Pectobacterium atrosepticum, Citrobacter rodentium, Serratia sp. ATCC39006, Serratia plymuthica, Dickeya dadantii, and many more. Transposon mutagenesis was optimized in each of these strains and three studies are presented to show the efficacy of this system. Firstly, the important agricultural pathogen D. dadantii was mutagenized. Two mutants that showed reduced protease production and one mutant producing the previously cryptic pigment, indigoidine, were identified and characterized. Secondly, the enterobacterium, Serratia sp. ATCC39006 was mutagenized and mutants incapable of producing gas vesicles, proteinaceous intracellular organelles, were identified. One of these contained a β-galactosidase transcriptional fusion within the gene gvpA1, essential for gas vesicle production. Finally, the system was used to mutate the biosynthetic gene clusters of the antifungal, anti-oomycete and anticancer polyketide, oocydin A, in the plant-associated enterobacterium, Dickeya solani MK10. The mutagenesis system was developed to allow easy identification of transposon insertion sites by sequencing, after facile generation of a replicon encompassing the transposon and adjacent DNA, post-excision. Furthermore, the system can also create transcriptional fusions with either β-galactosidase or β-glucuronidase as reporters, and exploits a variety of drug resistance markers so that multiple selectable fusions can be generated in a single strain. This system of various transposons has wide utility and can be combined in many different ways.The authors would like to acknowledge several funding sources. D. Smith was supported by a PhD studentship from the BBSRC. Work in the MW lab is supported by the BBSRC (grants BB/G015171/1 and BB/M019411/1). K. Roberts was funded by an MRC studentship. R. Monson and the Salmond lab were supported by grants from the BBSRC (Grant No Provisional BB/K001833/1). M.A. Matilla was supported by the EU Marie-Curie Intra-European Fellowship for Career Development (FP7-PEOPLE-2011-IEF), grant number 298003. B. Richardson was supported by a Harry Smith vacation studentship from the SGM, UK. The authors would also like to thank Ray Chai for careful reading and comments on this manuscript. Alison Drew provided technical support. Work with plant pathogens was carried out under DEFRA licence No. 50864/197900/1.This is the final version of the article. It was first available from Frontiers via http://dx.doi.org/10.3389/fmicb.2015.0144

Pathogenicity and pathogenesis of a United States porcine deltacoronavirus cell culture isolate in 5-day-old neonatal piglets

AbstractPorcine deltacoronavirus (PDCoV) was first identified in Hong Kong in 2009–2010 and reported in United States swine for the first time in February 2014. However, diagnostic tools other than polymerase chain reaction for PDCoV detection were lacking and Koch׳s postulates had not been fulfilled to confirm the pathogenic potential of PDCoV. In the present study, PDCoV peptide-specific rabbit antisera were developed and used in immunofluorescence and immunohistochemistry assays to assist PDCoV diagnostics. The pathogenicity and pathogenesis of PDCoV was investigated following orogastric inoculation of 5-day-old piglets with a plaque-purified PDCoV cell culture isolate (3×104 TCID50 per pig). The PDCoV-inoculated piglets developed mild to moderate diarrhea, shed increasing amount of virus in rectal swabs from 2 to 7 days post inoculation, and developed macroscopic and microscopic lesions in small intestines with viral antigen confirmed by immunohistochemistry staining. This study experimentally confirmed PDCoV pathogenicity and characterized PDCoV pathogenesis in neonatal piglets