Inherent batch to batch variability, ageing and contamination are major factors contributing to variability in oilfield cement slurry performance. Of particular concern are problems encountered when a slurry is formulated with one cement sample and used with a batch having different properties. Such variability imposes a heavy burden on performance testing and is often a major factor in operational failure. We describe methods which allow the identification, characterisation and prediction of the variability of oilfield cements. Our approach involves predicting cement compositions, particle size distributions and thickening time curves from the diffuse reflectance infrared Fourier transform spectrum of neat cement powders.

A call comes through on my tablet. It's a familiar digital voice letting me know that one of GE's power generation turbines installed at a utility customer's power plant was experiencing a change in its operating profile. This change was causing a critical part to wear more rapidly than usual. It would not necessarily cause a problem today, explains the caller, or even in the coming months. But further down the line, it could become an issue that would reduce the overall performance of the power plant and lead to more expensive repairs.

To the average person, it may seem that the biggest technology advances of 2015 were the larger smartphone screens and small app updates. But a lot more happened than that. A broad range of technologies reached a tipping point, from cool science projects or objects of convenience for the rich, to inventions that will transform humanity. We haven't seen anything of this magnitude since the invention of the printing press in the 1400s. In the developed world, we have become used to having devices that connect and inform us and provide services on demand, and the developing world has largely been in the dark.

"When you set your story in a specific city, it's a very sensitive thing to do," said David Cage, the director of the upcoming PlayStation 4 exclusive Detroit: Become Human. "You don't want to do it if you're not respectful of the place, of the people living there." Cage's next game with studio Quantic Dream deals with a near-future world where androids aren't a mobile operating system for your phone; instead they're "living" among us with hopes and desires of their own. Transcending their circuitry and, as the name suggests, being human. Detroit tells the story of several humanoid robots and is set entirely in the Motor City.

With the deluge of reports lately on how robots are replacing humans at everyday tasks, you may think the end of the world, at least for a certain category of human workers, is nigh. Indeed that may well be the case in certain professions. The Associated Press, for instance, has a team of robots that generates 3,000 news reports about the quarterly earnings releases of companies. This Japanese hotel that I wrote about recently is staffed entirely with robots. The paralegal may soon be a position of the past as law firms commission bots to sift through vast reams of legal information and synthesise them.

Germany's RDK8 is the world's most efficient coal-fired power plant. The U.N. and governing bodies around the globe are setting new goals for reducing carbon emissions, but that doesn't change the fact that a big portion of the world is still largely reliant on coal-generated power. Moreover, the firms running coal-fired plants aren't going to simply give up on their investments. That's why GE this week unveiled a new set of digital technologies that, using data science, software and intelligent automation, can optimize any coal-fired power plant. If the new, equipment-agnostic technology, called "Digital Power Plant for Steam," were deployed at every existing coal-fired power plant globally, it could eliminate 500 million metric tons of greenhouse gas emissions, GE says -- the equivalent of removing 120 million cars from the road.

If you're considering solar power but aren't quite sure it's worth the expense, Google wants to point you in the right direction. Tapping its trove of satellite imagery and the latest in artificial intelligence, the company is offering a new online service that will instantly estimate how much you'll save with a roof full of solar panels. On Monday, the company unveiled Project Sunroof, a tool that calculates your home's solar power potential using the same high-resolution aerial photos Google Earth uses to map the planet. After creating a 3-D model of your roof, the service estimates how much sun will hit those solar panels during the year and how much money the panels could save you over the next two decades. "People search Google all the time to learn about solar," says Google's Joel Conkling.

Optimistic government officials and automakers want to put millions of electric cars on American roads in the next decade. There are a lot of issues to be solved to make that happen (limited range, insufficient infrastructure, high costs, to name the big three), but if we ever get there, we'll be faced with a new problem: How to ensure the country's aging electrical grid can handle the added strain of charging millions of cars every day. We've got a while before that becomes a real issue, but it's something electric companies and their suppliers are already thinking about. It's a complicated problem, which is why General Electric, teaming up with Con Edison and researchers Columbia University's Center for Computational Learning, has picked out one element of the puzzle to address first: How to run EV chargers in New York City buildings without also running up a ginormous bill. It turns out that in NYC, very large buildings, which often include parking garages and EV chargers, are billed on both their total energy usage and their peak usage, the maximum amount of power used in a 15-minute window during a month.

This has bad results, of course, if you're a human. But not so much if you're a robot and have as many legs as a centipede sticking out from your body. That's why Mark Tilden, a robotics physicist at the Los Alamos National Laboratory, built something like that. At the Yuma Test Grounds in Arizona, the autonomous robot, 5 feet long and modeled on a stick-insect, strutted out for a live-fire test and worked beautifully, he says. Every time it found a mine, blew it up and lost a limb, it picked itself up and readjusted to move forward on its remaining legs, continuing to clear a path through the minefield.