Hydrogen storage studies of mesoporous and titanium based materials

Concerns over green house gas emissions and their climate change effects have lead to a concerted effort into environmental friendly technologies. One such emphasis has been on the implementation of the hydrogen economy. There are four major impediments to the implementation of a hydrogen economy: hydrogen production, distribution, storage and conversion. This thesis is focused on exploring the hydrogen storage problem. Hydrogen can be stored by a wide range of methods. One of these methods involves using a secondary material that stores hydrogen by either physisorbing hydrogen onto its surfaces or by reacting with it to form a new compound. Of the wide variety of materials that can interact with hydrogen, three different materials were chosen; (1) nano-structured materials of high surface area; mesoporous silica (MCM-41) and titanate nanotubes, and (2) hydrides of Ti-Mg-Ni alloys. Results of the hydrogen on mesoporous silica (MCM-41) showed 1 wt.% H[subscript]2 to a maximum of 2 wt.% H[subscript]2 for 500 to 1060 m2/g surface area, respectively, at 77 K. Doping these samples with Al or Zn did not make an appreciable difference but rather they reduced the surface area available for hydrogen adsorption. Adorption of hydrogen at room temperature was neglifible (0.1 wt.% up to an equilibrium pressure of 5 MPa). Sodium titanate nanotubes showed hydrogen adsorption that increased with increasing hydrogen pressure at 77 K. Hydrogen adsorption reached 0.4 wt.% at an hydrogen equilibrium pressure of 2.6 MPa. Exchange of sodium ions in the titanate nanotubes with Zn and Li did not have an impact on hydrogen adsorption.However, partial substitution of Na ions for H ions resulted in an increase in hydrogen adsorption from 0.4 wt.% to 0.8 wt.% while decreasing the pressure required for maximum hydrogen uptake from 2.6 MPa to 0.5 MPa at 77 K. Desorption from this sample also showed strong hysteresis indicating hydrogen adsorption into the interlayer spacing of the nanotube wall. Hydrogen adsorption at room temperature was negligible for all samples being below 0.1 wt.%, up to a hydrogen equilibrium pressure of 5 MPa. Ti-Mg-Ni alloys are interest as 11 wt.% hydrogen has been reported in the literature; specifically for Ti53Mg47Ni20. Samples with various stoichiometries of Ti, Mg and Ni were produced via balling and their hydrogen sorption properties examined. Measured hydrogen absorption ranged from 2.5 wt.% to 5.0 wt.%. Measurements were hindered by the high temperature (723 K) used during the activation process. The high temperature ensured decomposition of titanium hydride but resulted in the vaporisation and deposition of magnesium on the sample cell filter. This had the duel effect of reducing the total hydrogen absorption and to sporadically block the sample cell filter. However, in those cases where the hydrogen flow was not impeded, absorption kinetics were measured to be extremely rapid. For example, greater than 95 % of the total hydrogen uptake of 3.7 wt.% for the sample ball-milled in the molar ratio of 65:133:20 (Ti:Mg:Ni) occurred within 60 seconds at room temperature.However, the low equilibrium pressure meant a negligible amount of hydrogen could be desorbed at this temperature. X-ray diffraction revealed that after hydriding, the samples comprised varius mixtures of MgH[subscript]2, TiH[subscript]2 and hydrides of the intermetallic compounds Mg[subscript]2Ni and Ti[subscript]2Ni. The amount of each of these hydride phases changed according the intial starting stoichiometries of each sample

The influence of end of day silicone hydrogel daily disposable contact lens fit on ocular comfort, physiology and lens wettability

Purpose: To quantify the end-of-day silicone-hydrogel daily disposable contact lens fit and its influence of on ocular comfort, physiology and lens wettability. Methods: Thirty-nine subjects (22.1. ±. 3.5 years) were randomised to wear each of 3 silicone-hydrogel daily-disposable contact lenses (narafilcon A, delefilcon A and filcon II 3), bilaterally, for one week. Lens fit was assessed objectively using a digital video slit-lamp at 8, 12 and 16. h after lens insertion. Hyperaemia, non-invasive tear break-up time, tear meniscus height and comfort were also evaluated at these timepoints, while corneal and conjunctival staining were assessed on lens removal. Results: Lens fit assessments were not different between brands (P > 0.05), with the exception of the movement at blink where narafilcon A was more mobile. Overall, lag reduced but push-up speed increased from 8 to 12. h (P 0.05). Movement-on-blink was unaffected by wear-time (F = 0.403, P = 0.670). A more mobile lens fit with one brand did not indicate that person would have a more mobile fit with another brand (r = -0.06 to 0.63). Lens fit was not correlated with comfort, ocular physiology or lens wettability (P > 0.01). Conclusions: Among the lenses tested, objective lens fit changed between 8. h and 12. h of lens wear. The weak correlation in individual lens fit between brands indicates that fit is dependent on more than ocular shape. Consequently, substitution of a different lens brand with similar parameters will not necessarily provide comparable lens fit

Application of hydrides in hydrogen storage and compression: Achievements, outlook and perspectives

Metal hydrides are known as a potential efficient, low-risk option for high-density hydrogen storage since the late 1970s. In this paper, the present status and the future perspectives of the use of metal hydrides for hydrogen storage are discussed. Since the early 1990s, interstitial metal hydrides are known as base materials for Ni – metal hydride rechargeable batteries. For hydrogen storage, metal hydride systems have been developed in the 2010s [1] for use in emergency or backup power units, i. e. for stationary applications. With the development and completion of the first submarines of the U212 A series by HDW (now Thyssen Krupp Marine Systems) in 2003 and its export class U214 in 2004, the use of metal hydrides for hydrogen storage in mobile applications has been established, with new application fields coming into focus. In the last decades, a huge number of new intermetallic and partially covalent hydrogen absorbing compounds has been identified and partly more, partly less extensively characterized. In addition, based on the thermodynamic properties of metal hydrides, this class of materials gives the opportunity to develop a new hydrogen compression technology. They allow the direct conversion from thermal energy into the compression of hydrogen gas without the need of any moving parts. Such compressors have been developed and are nowadays commercially available for pressures up to 200 bar. Metal hydride based compressors for higher pressures are under development. Moreover, storage systems consisting of the combination of metal hydrides and high-pressure vessels have been proposed as a realistic solution for on-board hydrogen storage on fuel cell vehicles. In the frame of the “Hydrogen Storage Systems for Mobile and Stationary Applications” Group in the International Energy Agency (IEA) Hydrogen Task 32 “Hydrogen-based energy storage”, different compounds have been and will be scaled-up in the near future and tested in the range of 500 g to several hundred kg for use in hydrogen storage applications.Fil: Bellosta von Colbe, Jose. Helmholtz-Zentrum Geesthacht; AlemaniaFil: Ares Fernández, José Ramón. Universidad Autónoma de Madrid; EspañaFil: Jussara, Barale. Università di Torino; ItaliaFil: Baricco, Marcello. Università di Torino; ItaliaFil: Buckley, Craig E.. Curtin University; AustraliaFil: Capurso, Giovanni. Helmholtz Zentrum Geesthacht; AlemaniaFil: Gallandat, Noris. GRZ Technologies Ltd; SuizaFil: Grant, David M.. Science and Technology Facilities Council of Nottingham. Rutherford Appleton Laboratory; Reino Unido. University of Nottingham; Estados UnidosFil: Guzik, Matylda N.. University of Oslo; NoruegaFil: Jacob, Isaac. Ben Gurion University of the Negev; IsraelFil: Jensen, Emil H.. University of Oslo; NoruegaFil: Jensen, Torben. University Aarhus; DinamarcaFil: Jepsen, Julian. Helmholtz Zentrum Geesthacht; AlemaniaFil: Klassen, Thomas. Helmholtz Zentrum Geesthacht; AlemaniaFil: Lototskyy, Mykhaylol V.. University of Cape Town; SudáfricaFil: Manickam, Kandavel. University of Nottingham; Estados Unidos. Science and Technology Facilities Council of Nottingham. Rutherford Appleton Laboratory; Reino UnidoFil: Montone, Amelia. Casaccia Research Centre; ItaliaFil: Puszkiel, Julián Atilio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Helmholtz Zentrum Geesthacht; AlemaniaFil: Sartori, Sabrina. University of Oslo; NoruegaFil: Sheppard, Drew A.. Curtin University; AustraliaFil: Stuart, Alastair. University of Nottingham; Estados Unidos. Science and Technology Facilities Council of Nottingham. Rutherford Appleton Laboratory; Reino UnidoFil: Walker, Gavin. University of Nottingham; Estados Unidos. Science and Technology Facilities Council of Nottingham. Rutherford Appleton Laboratory; Reino UnidoFil: Webb, Colin J.. Griffith University; AustraliaFil: Yang, Heena. Empa Materials Science & Technology; Suiza. École Polytechnique Fédérale de Lausanne; SuizaFil: Yartys, Volodymyr. Institute for Energy Technology; NoruegaFil: Züttel, Andreas. Empa Materials Science & Technology; Suiza. École Polytechnique Fédérale de Lausanne; SuizaFil: Dornheim, Martin. Helmholtz Zentrum Geesthacht; Alemani

Protecting the environment through insect farming as a means to produce protein for use as livestock, poultry, and aquaculture feed

Securing protein for the approximate 10 billion humans expected to inhabit our planet by 2050 is a major priority for the global community. Evidence has accrued over the past 30 years that strongly supports and justifies the sustainable use of insects as a means to produce protein products as feed for pets, livestock, poultry, and aquacultured species. Researchers and entrepreneurs affiliated with universities and industries, respectively, from 18 nations distributed across North and South America, Europe, Asia, Africa and Australia contributed to the development of this article, which is an indication of the global interest on this topic. A brief overview of insects as feed for the aquaculture industry along with a review of the black soldier fly, Hermetia illucens (Diptera: Stratiomyidae), as a model for such systems is provided

Trends in invasive bacterial diseases during the first 2 years of the COVID-19 pandemic: analyses of prospective surveillance data from 30 countries and territories in the IRIS Consortium.

BACKGROUND The Invasive Respiratory Infection Surveillance (IRIS) Consortium was established to assess the impact of the COVID-19 pandemic on invasive diseases caused by Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, and Streptococcus agalactiae. We aimed to analyse the incidence and distribution of these diseases during the first 2 years of the COVID-19 pandemic compared to the 2 years preceding the pandemic. METHODS For this prospective analysis, laboratories in 30 countries and territories representing five continents submitted surveillance data from Jan 1, 2018, to Jan 2, 2022, to private projects within databases in PubMLST. The impact of COVID-19 containment measures on the overall number of cases was analysed, and changes in disease distributions by patient age and serotype or group were examined. Interrupted time-series analyses were done to quantify the impact of pandemic response measures and their relaxation on disease rates, and autoregressive integrated moving average models were used to estimate effect sizes and forecast counterfactual trends by hemisphere. FINDINGS Overall, 116 841 cases were analysed: 76 481 in 2018-19, before the pandemic, and 40 360 in 2020-21, during the pandemic. During the pandemic there was a significant reduction in the risk of disease caused by S pneumoniae (risk ratio 0·47; 95% CI 0·40-0·55), H influenzae (0·51; 0·40-0·66) and N meningitidis (0·26; 0·21-0·31), while no significant changes were observed for S agalactiae (1·02; 0·75-1·40), which is not transmitted via the respiratory route. No major changes in the distribution of cases were observed when stratified by patient age or serotype or group. An estimated 36 289 (95% prediction interval 17 145-55 434) cases of invasive bacterial disease were averted during the first 2 years of the pandemic among IRIS-participating countries and territories. INTERPRETATION COVID-19 containment measures were associated with a sustained decrease in the incidence of invasive disease caused by S pneumoniae, H influenzae, and N meningitidis during the first 2 years of the pandemic, but cases began to increase in some countries towards the end of 2021 as pandemic restrictions were lifted. These IRIS data provide a better understanding of microbial transmission, will inform vaccine development and implementation, and can contribute to health-care service planning and provision of policies. FUNDING Wellcome Trust, NIHR Oxford Biomedical Research Centre, Spanish Ministry of Science and Innovation, Korea Disease Control and Prevention Agency, Torsten Söderberg Foundation, Stockholm County Council, Swedish Research Council, German Federal Ministry of Health, Robert Koch Institute, Pfizer, Merck, and the Greek National Public Health Organization

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Effects of fluoxetine on functional outcomes after acute stroke (FOCUS): a pragmatic, double-blind, randomised, controlled trial

Background Results of small trials indicate that fluoxetine might improve functional outcomes after stroke. The FOCUS trial aimed to provide a precise estimate of these effects. Methods FOCUS was a pragmatic, multicentre, parallel group, double-blind, randomised, placebo-controlled trial done at 103 hospitals in the UK. Patients were eligible if they were aged 18 years or older, had a clinical stroke diagnosis, were enrolled and randomly assigned between 2 days and 15 days after onset, and had focal neurological deficits. Patients were randomly allocated fluoxetine 20 mg or matching placebo orally once daily for 6 months via a web-based system by use of a minimisation algorithm. The primary outcome was functional status, measured with the modified Rankin Scale (mRS), at 6 months. Patients, carers, health-care staff, and the trial team were masked to treatment allocation. Functional status was assessed at 6 months and 12 months after randomisation. Patients were analysed according to their treatment allocation. This trial is registered with the ISRCTN registry, number ISRCTN83290762. Findings Between Sept 10, 2012, and March 31, 2017, 3127 patients were recruited. 1564 patients were allocated fluoxetine and 1563 allocated placebo. mRS data at 6 months were available for 1553 (99·3%) patients in each treatment group. The distribution across mRS categories at 6 months was similar in the fluoxetine and placebo groups (common odds ratio adjusted for minimisation variables 0·951 [95% CI 0·839–1·079]; p=0·439). Patients allocated fluoxetine were less likely than those allocated placebo to develop new depression by 6 months (210 [13·43%] patients vs 269 [17·21%]; difference 3·78% [95% CI 1·26–6·30]; p=0·0033), but they had more bone fractures (45 [2·88%] vs 23 [1·47%]; difference 1·41% [95% CI 0·38–2·43]; p=0·0070). There were no significant differences in any other event at 6 or 12 months. Interpretation Fluoxetine 20 mg given daily for 6 months after acute stroke does not seem to improve functional outcomes. Although the treatment reduced the occurrence of depression, it increased the frequency of bone fractures. These results do not support the routine use of fluoxetine either for the prevention of post-stroke depression or to promote recovery of function. Funding UK Stroke Association and NIHR Health Technology Assessment Programme

Density Functional Theory Calculations of Magnesium Hydride: A Comparison of Bulk and Nanoparticle Thermodynamics

Density functional theory calculations have been performed on a range of magnesium and magnesium hydride nanoclusters to examine the 1 bar desorption temperatures. The vibrational entropies and enthalpies are calculated for each cluster, within the harmonic approximation, which permits calculation of the desorption Gibbs free energy of reaction. For the bulk system, good agreement is found with experiment for the desorption temperature and a range of structural and electronic properties. For the nanoparticulate systems, we report binding energies, along with desorption reaction entropies and enthalpies. The finite-temperature effects on the vibrational energies of all system sizes are examined, and the findings suggest that the harmonic approximation is too restricted to account for the experimentally observed reductions in the nanoparticulate reaction enthalpies

Novel multi-stage aluminium production: part 2 – experimental investigation on carbosulphidation of Al2O3 using H2S and sodiothermic reduction of Al2S3

In this paper, experimental investigation on the carbosulphidation of alumina (Al2O3) for aluminium (Al) production and the sodiothermic reduction of aluminium sulphide (Al2S3) are presented. Hydrogen sulphide (H2S) was used as a reductant and source of sulphur. This work is the second of two-parts paper series. The experimental investigations of the Stage-1 process (Al2O3 carbosulphidation) were carried out at 1100–1600°C using a laboratory scale horizontal tube resistance-furnace. H2S gas, diluted with argon (5% H2S and 95% Ar), was reacted with pellets of a mixture of γ-Al2O3 and C powders (1:6 molar ratio) to produce Al2S3. The effects of gas injection rate, pelletizing pressure, temperature and reaction time on the conversion of Al2O3 to Al2S3 were investigated. The X-ray diffraction results confirmed the formation of Al2S3(s) in the reaction product above 1400°C. The conversion of Al2O3 to Al2S3 was found to be 99.5% at 1600°C and 12 h. The kinetics analysis of alumina sulphidation using Ginstling-Brounshtein diffusion model suggested the overall reaction was controlled by the diffusion of H2S gas through the reaction product (liquid Al2S3). The activation energy of the alumina sulphidation reaction was calculated to be 148.5 kJ mol−1. It has also been demonstrated in this study that Al can be extracted from Al2S3 by sodiothermic reduction using Na or NaH. In the case of Na, a level of Al conversion of 75% has been observed for reaction at 290°C

Novel multi-stage aluminium production: part 1 - thermodynamic assessment of carbosulphidation of Al2O3/bauxite using H2S and sodiothermic reduction of Al2S3

A novel multi-stage Al production through a carbosulphidation of Al2O3, followed by a sodiothermic reduction of Al2S3, was proposed. In Stage-1, alumina (or bauxite) is reduced to Al2S3 in the presence of carbon and H2S. In Stage-2, Al2S3 is reduced to Al through reactions with Na or NaH. The thermodynamic analysis predicted Al2S3 to be the main intermediate Alcompound when H2S is reacted with Al2S3 and C at 1000-2000°C at 1 atm. Al2S3 formation was predicted to be low at 1100-1300°C at 1 atm (0.1 moles/mole Al2O3) but increased with increasing temperature (0.96 moles/mole Al2O3 at 1800°C). The thermodynamic analysis of sodiothermic reduction predicted that Al metal can be extracted from Al2S3 below 800°C at 1 atm. The Na2S produced can be hydrolysed to form H2S and NaOH. H2S can be re-used and the Na can be reproduced from NaOH and put back into the process