Asynchronous quantum key distribution on a relay network

We show how quantum key distribution on a multi-user, multi-path, network can be used to establish a key between any two end-users in an asynchronous fashion using the technique of bit-transport. By a suitable adaptation of our previous secret-sharing scheme we show that an attacker has to compromise all of the intermediate relays on the network in order to obtain the key. Thus, two end-users can establish a secret key provided they trust at least one of the network relays

Securing a Quantum Key Distribution Network Using Secret Sharing

We present a simple new technique to secure quantum key distribution relay networks using secret sharing. Previous techniques have relied on creating distinct physical paths in order to create the shares. We show, however, how this can be achieved on a single physical path by creating distinct logical channels. The technique utilizes a random 'drop-out' scheme to ensure that an attacker must compromise all of the relays on the channel in order to access the key

Extending the Reach of QKD Using Relays

One of the obstacles to deployment of QKD solutions has been the distance limitation. Solutions using relays have been proposed but these rely on link-by-link key establishment. We present a new technique to extend the distance of a quantum key distribution channel using an active relay. Each relay acts as an intercept/resend device and allows the establishment of an end-to-end key. It has been argued that such relays cannot be used to extend the distance, but we show that with a suitable adaptation of the protocol the effective key distribution distance can be increased

The unexpected influence of microbiology on the disposal of radioactive waste

The safe disposal of radioactive waste in repositories constructed deep underground might not sound like a topic that requires much input from microbiologists, but a surprising amount of work has been carried out around the world on how microorganisms might be beneficial or harmful for the safe containment of such waste. The UK has a legacy of radioactive waste from activities such as power generation, medical applications, defence and research. This material is currently securely stored at sites around the UK. The UK government, and those of many other countries have identified that the best and safest approach to long‐term management of this waste, in particular, higher activity waste, is through ‘geological disposal’ (placing the waste in carefully engineered chambers deep underground). This repository will be constructed between 200 m and 1000 m below the surface, in a geological setting that has been carefully selected for its ability to contain the waste for hundreds of thousands of years and will isolate waste until harmful radionuclides have decayed sufficiently. The repository itself will be highly engineered and contain multiple barriers (the last of which is the mass of rock between it and the surface) designed to limit any release of radionuclides. The UK government published a White Paper in 2014 setting out how it will implement geological disposal and is currently undertaking a national exercise collating information about the different types of rocks that occur to depths of about 1000 m beneath England, Wales and Northern Ireland

Comparison of heterotrophic bioleaching and ammonium sulfate ion exchange leaching of Rare Earth Elements from a Madagascan Ion-Adsorption Clay

Rare earth elements (REE) are considered to be a critical resource, because of their importance in green energy applications and the overdependence on Chinese imports. REE rich ion-adsorption deposits (IAD) result from tropical weathering of REE enriched igneous rocks. Commercial REE leaching from IAD, using salt solutions occurs via an ion-exchange mechanism. Bioleaching of IAD by Aspergillus or Bacillus, was compared to Uninoculated Control and Salt leaching (0.5 M ammonium sulfate) over 60 days. Salt leaching was most effective, followed by Aspergillus, Bacillus then Uninoculated Control. Most of the REE and major elements released by Salt leaching occurred before day 3. With bioleaching, REE and major elements release increased with time and had a greater heavy to light REE ratio. Similar total heavy REE release was observed in Salt leaching and Aspergillus (73.1% and 70.7% Lu respectively). In bioleaching experiments, pH was inversely correlated with REE release (R2 = 0.947 for Lu) indicating leaching by microbially produced acids. These experiments show the potential for bioleaching of REE from IAD, but dissolution of undesirable elements could cause problems in downstream processing. Further understanding of the bioleaching mechanisms could lead to optimization of REE recover

Design of LabVIEW®-based software for the control of sequential injection analysis instrumentation for the determination of morphine

LabVIEW®-based software for the automation of a sequential injection analysis instrument for the determination of morphine is presented. Detection was based on its chemiluminescence reaction with acidic potassium permanganate in the presence of sodium polyphosphate. The calibration function approximated linearity (range 5 × 10-10 to 5 × 10-6 M) with a line of best fit of y=1.05x+8.9164 (R2 =0.9959), where y is the log10 signal (mV) and x is the log10 morphine concentration (M). Precision, as measured by relative standard deviation, was 0.7% for five replicate analyses of morphine standard (5 × 10-8 M). The limit of detection (3σ) was determined as 5 × 10-11 M morphine