Fabricate 2020

Fabricate 2020 is the fourth title in the FABRICATE series on the theme of digital fabrication and published in conjunction with a triennial conference (London, April 2020). The book features cutting-edge built projects and work-in-progress from both academia and practice. It brings together pioneers in design and making from across the fields of architecture, construction, engineering, manufacturing, materials technology and computation. Fabricate 2020 includes 32 illustrated articles punctuated by four conversations between world-leading experts from design to engineering, discussing themes such as drawing-to-production, behavioural composites, robotic assembly, and digital craft

Effect of organic solvents on the separation of benzoic acids by capillary electrophoresis

The effect of organic modifiers on the separation of a number of closely related isomeric benzoic acids by capillary electrophoresis is described. It is shown that while a single modifier concentration cannot help resolve the entire electropherogram, organic modifiers do significantly enhance the resolution of parts of the separation system by comparison with 40 mmol l-1 phosphate buffer. The effects on separation and retention times are discussed in terms of the effects on electroosmotic flow and the electrophoretic mobilities of the charged solutes. The effects were found to be modifier specific, although the trends were in the same direction (ie., decreasing electroosmotic flow with increased percentage of organic modifier). The major influence is the manipulation of the electroosmotic mobility

Microdroplet-tin plasma sources of EUV radiation driven by solid-state-lasers (Topical Review)

Plasma produced from molten-tin microdroplets generates extreme ultraviolet light for state-of-the-art nanolithography. Currently, CO2 lasers are used to drive the plasma. In the future, solid-state mid-infrared lasers may instead be used to efficiently pump the plasma. Such laser systems have promise to be more compact, better scalable, and have higher wall-plug efficiency. In this Topical Review, we present recent findings made at the Advanced Research Center for Nanolithography (ARCNL) on using 1 and 2 μm wavelength solid-state lasers for tin target preparation and for driving hot and dense plasma. The ARCNL research ranges from advanced laser development, studies of fluid dynamic response of droplets to impact, radiation-hydrodynamics calculations of, e.g. ion 'debris', (EUV) spectroscopic studies of tin laser-produced-plasma as well as high-conversion efficiency operation of 2 μm wavelength driven plasma

Stability of interleukin 8 and neutrophil elastase in bronchoalveolar lavage fluid following long-term storage

AbstractBackgroundInterleukin-8 (IL-8) and neutrophil elastase (NE) are commonly measured markers of inflammation in bronchoalveolar lavage (BAL) fluid from patients with cystic fibrosis. Longitudinal analysis assumes uniform stability during storage, however the effect of extended low-temperature storage on these markers remains unclear.MethodsBAL fluid from 104 children with cystic fibrosis was assayed for IL-8 and NE after storage at 4°C for 7days and −80°C for up to 6years and compared with the initial assays performed soon after collection.ResultsIL-8 levels were stable after any measured length of time at −80°C or 4°C. NE levels were stable for 6months at −80°C but decreased beyond that or after 7days at 4°C.ConclusionsOur data support the stability of IL-8 in BAL stored at −80°C for prolonged periods. NE in BAL decreases with storage and should be assayed as soon as practical after collection

High-energy ions from Nd:YAG laser ablation of tin microdroplets:Comparison between experiment and a single-fluid hydrodynamic model

We present the results of a joint experimental and theoretical study of plasma expansion arising from Nd:YAG laser ablation (laser wavelength λ = 1.064 μm) of tin microdroplets in the context of extreme ultraviolet lithography. Measurements of the ion energy distribution reveal a near-plateau in the distribution for kinetic energies in the range 0.03-1 keV and a peak near 2 keV followed by a sharp fall-off in the distribution for energies above 2 keV. Charge-state resolved measurements attribute this peak to the existence of peaks centered near 2 keV in the Sn3+-Sn8+ ion energy distributions. To better understand the physical processes governing the shape of the ion energy distribution, we have modelled the laser-droplet interaction and subsequent plasma expansion using two-dimensional radiation hydrodynamic simulations. We find excellent agreement between the simulated ion energy distribution and the measurements both in terms of the shape of the distribution and the absolute number of detected ions. We attribute a peak in the distribution near 2 keV to a quasi-spherical expanding shell formed at early times in the expansion

Characterization of 1- and 2-mu m-wavelength laser-produced microdroplet-tin plasma for generating extreme-ultraviolet light

Experimental spectroscopic studies are presented, in a 5.5-25.5 nm extreme-ultraviolet (EUV) wavelength range, of the light emitted from plasma produced by the irradiation of tin microdroplets by 5-ns-pulsed, 2-mu m-wavelength laser light. Emission spectra are compared to those obtained from plasma driven by 1-mu m-wavelength laser light over a range of laser intensities spanning approximately (0.3-5) x 10(11) W/cm(2), under otherwise identical conditions. Over this range of drive laser intensities, we find that similar spectra and underlying plasma charge state distributions are obtained when keeping the ratio of 1- to 2-mu m laser intensities fixed at a value of 2.1(6), which is in good agreement with RALEF-2D radiation-hydrodynamic simulations. Our experimental findings, supported by the simulations, indicate an approximately inversely proportional scaling similar to lambda(-1) of the relevant plasma electron density, and of the aforementioned required drive laser intensities, with drive laser wavelength lambda. This scaling also extends to the optical depth that is captured in the observed changes in spectra over a range of droplet diameters spanning 16-51 mu m at a constant laser intensity that maximizes the emission in a 2% bandwidth around 13.5 nm relative to the total spectral energy, the bandwidth relevant for EUV lithography. The significant improvement of the spectral performance of the 2-mu m- versus 1-mu m driven plasma provides strong motivation for the development of high-power, high-energy near-infrared lasers to enable the development of more efficient and powerful sources of EUV light

Orangutans venture out of the rainforest and into the Anthropocene

Conservation benefits from understanding how adaptability and threat interact to determine a taxon’s vulnerability. Recognizing how interactions with humans have shaped taxa such as the critically endangered orangutan (Pongo spp.) offers insights into this relationship. Orangutans are viewed as icons of wild nature, and most efforts to prevent their extinction have focused on protecting minimally disturbed habitat, with limited success. We synthesize fossil, archeological, genetic, and behavioral evidence to demonstrate that at least 70,000 years of human influence have shaped orangutan distribution, abundance, and ecology and will likely continue to do so in the future. Our findings indicate that orangutans are vulnerable to hunting but appear flexible in response to some other human activities. This highlights the need for a multifaceted, landscape-level approach to orangutan conservation that leverages sound policy and cooperation among government, private sector, and community stakeholders to prevent hunting, mitigate human-orangutan conflict, and preserve and reconnect remaining natural forests. Broad cooperation can be encouraged through incentives and strategies that focus on the common interests and concerns of different stakeholders. Orangutans provide an illustrative example of how acknowledging the long and pervasive influence of humans can improve strategies to preserve biodiversity in the Anthropocene

Rodents as potential hosts and reservoirs of parasites along the edge of a Central African forest: Bwindi impenetrable national park, South Western Uganda

Background: Rodents which constitute 42% of the world\u2019s mammalian population are major reservoirs of pathogens that cause zoonoses. Currently we know little about rodents\u2019 potential zoonotic transfer from human settlements into protected areas and how any such threats might be reduced. Objective: To investigate the role of rodents as reservoirs of zoonotic pathogens along the boundary of Bwindi. Methods: A rodent inventory in three villages along the edge of Bwindi, was carried using live trapping techniques and the local rodents\u2019 ecto and endoparasite fauna investigated. Results: Two hundred eighty eight rodents captured belonged to 24 species, 17 genera and 4 families with Lophuromys aquilus being most abundant (30.2%). 240 ectoparasites which included mites, fleas and ticks were collected from 88 rodents out of 249. Proamys jacksoni rodents were most infested. Although the mites represented the largest proportion (84.6%), the highest species diversity was shown among the fleas (9 species). Some 36.9% of the rodents were infected with endoparasites of which L. aquilus haboured most. Endoparasitic genera identified included Nippostrongylus, Ascaris , Strongyloides, Trichuris, Hymenolepis , Taenia and Cryptosporidium . Conclusion: Rodents have a zoonotic potentiality. There is need for developing effective integrated rodent management programs against rodent to reduce chances of parasite transmission within the protected areas