Cs Fountain Clocks for Commercial Realizations—An Improved and Robust Design

We report on the design, assembly, testing, and delivery of a series of new cesium fountain primary frequency standards built through commercial and scientific collaboration with international users. The new design, based on proven National Physical Laboratory solutions, improves reliability, simplicity of operation, and transportability. The complete system consists of a novel physics package, a specially developed optical package, and dedicated electronics for system control. We present results showing that despite their simplified and more compact design, the new fountains have state-of-the-art performance in terms of signal-to-noise ratio and robust long-term operation. With a sufficiently low-noise local oscillator, they are capable of reaching a short-term stability below $3\times 10^{-14}$ (1 s) and have potential accuracy in the low $10^{-16}$ range, similar to the best cesium fountains currently in operation. This cost-effective solution could be used to increase the availability of accurate frequency references and timescales and provide redundancy in critical locations

SBS reduction in automated ventilation systems

Syndrom chorego budynku jest wynikiem obecności w powietrzu związków chemicznych podrażniających śluzówki, powodujących bóle i zawroty głowy oraz złe samopoczucie. Przyczyną wystąpienia takich związków może być ich emisja wewnątrz budynku, ale niejednokrotnie takie związki dostają się przez kanały wentylacyjne wraz z zasysanym powietrzem. Związane jest to ściśle ze spełnieniem norm komfortu cieplnego. Obecnie wiele systemów wentylacji jest zautomatyzowanych. Część powietrza cyrkuluje wewnątrz budynku, a wymianie ulega tylko tyle powietrza, ile jest konieczne, aby zachować odpowiednie standardy. Rozwiązanie to w połączeniu z rekuperacją ciepła jest znacznie bardziej energooszczędne. W pracy przedstawiono rozwiązanie oparte na zautomatyzowanym systemie wentylacji współpracującym z gruntowym wymiennikiem ciepła. Rozwiązanie to umożliwia utrzymanie niskiej energooszczędności oraz zapewnienie odpowiednich parametrów pobieranego powietrza z zewnątrz. Jednak wymaga stosowania odpowiednich filtrów redukujących ilość związków chemicznych dostających się do budynku wraz z zasysanym powietrzem. Obecnie znane są różne konstrukcje filtrów, zarówno pasywnych jak i aktywnych. W pracy opisano nowatorskie rozwiązanie zastosowania układu gruntowego wymiennika ciepła z biologicznym filtrem zoolitowym. Przedstawiono wyniki badań oraz określono procentowy stopień redukcji. Jak wynika z badań, gruntowe wymienniki ciepła redukują wiele związków chemicznych, jakie dostają się do nich wraz z powietrzem, ale są też emitorem tlenków węgla. Połączenie gruntowego wymiennika ciepła z filtrem zoolitowym powoduje, że te dwa urządzenia uzupełniają się w procesie redukcji zanieczyszczeń powietrza. W konsekwencji otrzymuje się powietrze o znacznie zregulowanym udziale związków chemicznych i odpowiedniej temperaturze.Sick building syndrome SBS is the result of the presence of chemical compounds in the air, irritating the mucous membrane, causing headaches, dizziness and malaise. The reason for the occurrence of such compounds may be their emission inside the building, but often these types of compounds get through ventilation channels along with the sucked air, which is closely related to meeting thermal comfort standards. At present, many ventilation systems are automated, in which part of the air circulates inside the building, and only as much air is exchanged as is necessary to maintain appropriate standards. This solution allows maintaining low energy efficiency and ensuring adequate parameters of the air taken in from the outside. However, it requires the use of appropriate filters to reduce the amount of chemicals entering the building along with the sucked air. Currently, various types of both passive and active filter solutions are known. The paper presents a solution based on an automated ventilation system in cooperation with a ground heat exchanger. Such solutions require the use of appropriate filters to reduce the amount of chemicals entering the building along with the sucked air. Currently, various types of both passive and active filter solutions are known. This paper describes an innovative solution to use the system ground heat exchanger with a zoolite biological filter. The results of the research were presented, and the percentage reduction rate was determined. Studies show that ground heat exchangers reduce the presence of chemical compounds in the air, but they are also an emitter of carbon oxides. The combination of a ground heat exchanger with a zoolite filter causes these two devices to complement each other in reducing air pollution. As a consequence, in this way air is obtained with a significantly regulated proportion of chemical compounds and appropriate temperature

Biological activity of α-galactoside preparations from Lupinus angustifolius L. and Pisum sativum L. seeds

Biological activity tests were performed on α-galactoside preparations obtained from Lupinus angustifolius L. cv. Mirela (alkaloid-rich) and Pisum sativum L. cv. Opal seeds. The studies included the following tests: acute toxicity, cytotoxic test, delayed type hypersensitivity (DTH), plaque-forming cell number (IgM-PFC), and influence on the growth of bifidobacteia and coliform presence in rat colon. Results of these studies showed that α-galactosides from lupin and pea seeds were essentially nontoxic. Their acute toxicity (LD50) in mice was >4000 mg kg-1 of body weight. α-Galactoside preparations were not cytotoxic for mouse thymocytes in vitro. The in vitro test shows that oligosaccharides from lupin and pea are utilized by selected beneficial colon bacterium strains. The in vivo experiment demonstrated that α-galactosides from legume significantly influenced the growth of bifidobacteria in rats colon. Simultaneously, the decrease of the coliform presence was observed. The chemical composition of the tested preparations had no significant effect on their biological activity.Peer Reviewe

The NRC-FCs2 primary frequency standard at the National Research Council Canada

At the National Research Council Canada, we are performing final assembly and initial testing of our new atomic fountain clock, NRC-FCs2. This fountain clock incorporates several improvements in the optical, microwave, and computer systems from our previous generation clock, NRC-FCs1, as well as a new physics package designed at the National Physical Laboratory (UK). With these changes, NRC-FCs2 is expected to reach uncertainties <; 5 710-16. We will discuss the recent improvements made in the various subsystems of NRC-FCs2 and present preliminary results in its evaluation.Peer reviewed: YesNRC publication: Ye

Analysis of atomic-clock data to constrain variations of fundamental constants

We present a new framework to study the time variation of fundamental constants in a model-independent way. Model independence implies more free parameters than assumed in previous studies. Using data from atomic clocks based on ^87 Sr, ^171 Yb ^+ and ^133 Cs, we set bounds on parameters controlling the variation of the fine-structure constant, α , and the electron-to-proton mass ratio, µ . We consider variations on timescales ranging from a minute to almost a day. In addition, we use our results to derive some of the tightest limits to date on the parameter space of models of ultralight dark matter and axion-like particles