The formation of mixed germanium–cobalt carbonyl clusters: an electrospray mass spectrometric study, and the structure of a high-nuclearity [Ge₂Co₁₀(CO)₂₄]²⁻ anion

The reaction of [µ₄-Ge{Co₂(CO)₇}₂] with [Co(CO)₄]⁻ has been monitored by electrospray mass spectrometry to detect the cluster anions generated. Conditions giving known mixed Ge–Co carbonyl clusters were established, and a new high nuclearity cluster anion, [Ge₂Co₁₀(CO)₂₄]²⁻ was detected. Conditions for its formation were optimised and it was subsequently isolated as its [Et₄N]⁺ salt and characterised by single-crystal X-ray crystallography. The Ge₂Co₁₀ cluster core has a novel geometry with the two germanium atoms in semi-encapsulated positions, forming seven formal Ge–Co bonds. There are also eighteen formal Co–Co bonds. Corresponding reactions of [µ₄-Si{Co₂(CO)₇}₂] with [Co(CO)₄]⁻ were also investigated

Online Thermal Analysis of Batch Roasted Coffee Beans

We constructed and instrumented a fluidised-bed coffee roaster. This work has been carried out as part of a search for the “ideal point”, which is the point in time when an expert roaster would terminate the roast in order to yield beans that produce the optimal brew. We roasted Costa Rican Arabica beans whilst controlling the roasting temperature to follow a linear ramp. We measured and recorded the input, output, and coffee bean surface temperatures. We introduce the idea of “bean load”, an uncalibrated measure of the heat load presented by the material being roasted. The bean load under constantly-ramping bean surface temperature shows the roast is increasingly endothermic. Toward the end of the roast the endothermic phenomena decrease, or are assisted by exothermic activity. The bean load also has a repeatable dip around first crack. Due to limitations with the roaster we were not able to make reliable measurements at and beyond second crack. We observed no waypoints or events that might be used to pinpoint the “ideal point” to end the roast

The preparation and characterisation of monomeric and linked metal carbonyl clusters containing the closo-Si2Co4 pseudo-octahedral core

PhSiH3 reacts with [Co₄(CO)₁₂] at 50 °C in hydrocarbon solvents to give [(µ₄-SiPh)₂Co₄(CO)₁₁], 2c, shown by an X-ray crystal structure determination to have a pseudo-octahedral Si₂Co₄ core. Substituted aryl-silanes behaved similarly. Mixtures of PhSiH₃, H₃SiC₆H₄SiH₃ and [Co₄(CO)₁₂] in a ca. 2 1 2 ratio gave the dimeric cluster [{Co₄(µ₄-SiPh)(CO)₁₁Si}₂C₆H₄], 3a, which has the two Si₂Co₄ cores linked by a C₆H₄ group to give a rigid molecule which an X-ray structure analysis shows to be over 23 Å long. Related dimers linked by –(CH₂)₈– groups were isolated from mixtures of PhSiH₃, α ,ω-(H₃Si)₂(CH₂)₈ and [Co₄(CO)₁₂]. Electrochemical studies show the two cluster units in 3a do not interact electronically

Advantages of 3D time-of-flight range imaging cameras in machine vision applications

Machine vision using image processing of traditional intensity images is in wide spread use. In many situations environmental conditions or object colours or shades cannot be controlled, leading to difficulties in correctly processing the images and requiring complicated processing algorithms. Many of these complications can be avoided by using range image data, instead of intensity data. This is because range image data represents the physical properties of object location and shape, practically independently of object colour or shading. The advantages of range image processing are presented, along with three example applications that show how robust machine vision results can be obtained with relatively simple range image processing in real-time applications

Proper Motions and Origins of SGR 1806–20 and SGR 1900+14

We present results from high-resolution infrared observations of magnetars SGR 1806–20 and SGR 1900+14 over 5 years using laser-supported adaptive optics at the 10 m Keck Observatory. Our measurements of the proper motions of these magnetars provide robust links between magnetars and their progenitors and provide age estimates for magnetars. At the measured distances of their putative associations, we measure the linear transverse velocity of SGR 1806–20 to be 350 ± 100 km s^(–1) and of SGR 1900+14 to be 130 ± 30 km s^(–1). The transverse velocity vectors for both magnetars point away from the clusters of massive stars, solidifying their proposed associations. Assuming that the magnetars were born in the clusters, we can estimate the braking index to be ~1.8 for SGR 1806–20 and ~1.2 for SGR 1900+14. This is significantly lower than the canonical value of n = 3 predicted by the magnetic dipole spin-down suggesting an alternative source of dissipation such as twisted magnetospheres or particle winds

Living it : children, young people, justice

Our main aim in editing this issue has been to create a space for those who had contact with the justice system as young people to share their experiences and reflections.This issue represents an attempt to shift power and control a bit from the professionals who usually edit these types of things, to people who have lived it