Dec 20, 2017 - For anyone who has marveled at the richly colored layers in a cafe latte, you're not alone. Princeton researchers, likewise intrigued, have now revealed how this tiered structure develops when espresso is poured into hot milk.
"The structure formation in a latte is surprising because it evolves from the chaotic, initial pouring and mixing of fluids into a very organized, distinct arrangement of layers," said Nan Xue, lead author of a paper describing the findings in Nature Communications, and a graduate student in the lab of Howard Stone, professor of mechanical and aerospace engineering at Princeton.
Honing techniques for yielding sought-after layers by flowing liquids into each other could reduce costs and complexity in a range of applications.
"From a manufacturing perspective, a single pouring process is much simpler than the traditional sequential stacking of layers in a stratified product," said Stone. "In one application of this study, we are exploring the physics behind making a whole layered structure with one step, rather than one-by-one stacking of the layers."
The inspiration for the research project came from an unsolicited, emailed picture of a layered coffee drink sent to Stone. With Xue looking for a project to take on as he started his graduate work, he initially investigated the concept by preparing lattes in the lab, using store-bought coffee and milk.
After several tries, it became clear to Xue that staying within only certain parameters, such as temperatures and pour rates, allowed for a characteristic café latte. These efforts hinted at the underlying, quantifiable physics that had to be involved in its liquid structure formation.
To control their model of latte layering with more precision, Xue and colleagues opted for a stand-in recipe that would make a barista shudder: dyed water substituting for the hot coffee, and salty, denser water for the warm milk.
A panel of light-emitting diodes and a camera then illuminated and captured the movement of fluids within the concoction. The researchers seeded the mixture with tracer particles, which scattered light from a green laser beam, to further track the faux-latte's internal dynamics, a technique called particle image velocimetry. Finally, numerical simulations were run to compare the collected data with various models of the evolving system of intermixing liquids.
The overall analysis showed that the primary mechanism behind the layering is a phenomenon known as double-diffusive convection. It occurs when stacked-up fluids of different densities, impelled by gravity to mix their contents, exchange heat through the movement of their constituent materials. Within a given mixture, denser, cooler liquids sink, while lighter, hotter liquids rise. This sinking and rising stops, however, when the local density in a region within a latte approaches an equilibrium. As a result, the fluid there has to flow horizontally, rather than vertically, creating distinct bands, or layers.
Through their experiments, the researchers examined how the velocity of the fluid injection of the warm milk matters as well. If poured too slowly, the denser fluid will mix too evenly as it flows into the less-dense fluid. A faster pour rate causes the former to punch through the latter and trigger the rapid movements that culminate in the desired layering when density equilibria are established.
Additional work needs to be done to characterize the layering effect demonstrated in lattes to extend control of it to other leveled liquids and semi-solids. But the preliminary findings from Xue and his colleagues already have shown how the activity within a common beverage could lead to uncommon insights. The same can be said for this engineering project focusing on cheese."This result shows the beauty of fluid mechanics and is very significant," said Detlef Lohse, a professor of fluid mechanics at the University of Twente in the Netherlands who was not involved with the study. "I think it will have bearing on various industrial flows and mixing procedures in so-called process technology, in which mixing of fluids with different densities by the injection of one into the other is omnipresent."
Lohse further pointed out how the Princeton research could help in better explaining heat- and salinity-dependent flows of water in Earth's vast oceans, a phenomenon that has key implications in climatology and ecology. "The most awesome finding may be that there is perfect analogy between the layering in a cafe latte," said Lohse, "and the known and extremely relevant layering of water with different temperatures and salt concentrations in the ocean."
For more coffee-related engineering, check out Adding Up the Perfect Cup.
Dec 19, 2017 - The challenges of high pressure have kept metal 3D printing from gaining widespread application in hydraulics technology, but we may begin seeing 3D-printed components in specialized applications.
One advantage of hydraulics technology is its high power density. Hydraulic pumps are typically a small fraction the size of the electric motors that drive them, and the size and weight differential between pumps and gas or diesel engines is even more pronounced. An even bigger advantage is with actuators. Hydraulic cylinders only a few inches in diameter can generate forces to lift thousands of pounds, crush rock and concrete, or form high-strength steel into rugged components.
Of course, another advantage of hydraulics is its ability to control direction, speed, torque, and force using anything from simple manually operated valves to sophisticated electronic controls to command valves automatically. And even though electronic control of hydraulic valves continues to advance, processes improvements for manufacturing the valves themselves have not been as dramatic. But that has started to change.
Where We Are and May Be Going
Cartridge valve technology is widely used to integrate several control functions into a single manifold. Centrally locating multiple valves within a manifold can dramatically reduce
Dec 15, 2017 - When six Wintec Māori and Pasifika engineering students volunteered for work experience at Longveld recently, they got to work on a very special project. Together they have made the framework for Hamilton’s Matariki Interactive Waka sculpture.
The work undertaken by the students on the waka ‘skeleton’ complemented their trade training as it required them to weld and assist with cutting steel while experiencing a real-world workplace.
Longveld directors Pam and Les Roa launched their business with little more than a toolbox, a welder and some great trade skills in the early 90s. They celebrate innovation and believe very strongly in culture and wellbeing. Their adoption of mātauranga Māori principles added a welcoming, cultural dimension to the students’ experience.
“We’re no strangers to interesting projects, in fact at Longveld we relish the challenge. To work with students who are embarking on a career in engineering, and at the same time help to create something that is so culturally significant for our community, is really inspiring for our team,” says Pam.
The students have been mentored by Longveld engineer Jemoal Lassey who says he has a new respect for teaching and learning.
“Upskilling these students, who I hope will become part of a new generation of engineers, was a reminder of how important it is to get the basics right, learn by doing and to ask questions along the way and challenge better ways of doing things,” says Jemoal.
Wintec tutor and PhD candidate Joe Citizen is behind the multidisciplinary Matariki Interactive Waka project which to date has involved Wintec students studying trades, engineering, early childhood education and media arts working with industry partners and Wintec’s Māori Achievement team.
“I can’t say enough how awesome it is that Longveld are involved and through this project they are mentoring our students. It was just wonderful to walk in there and see how they’re getting top-level mentorship in making a prototype that informs the cladding process,” says Joe.
“It’s real hands-on stuff. What’s particularly cool is the way I’m learning from the students, as they could tell me what the hard parts were and what they think needs to be done next.
“The next part will be working on the illuminated access hatches, which need to be integrated into the cladding design.”
Looking ahead, there are exciting plans for the Matariki Interactive Waka project as the sculpture nears completion in time for a June 2018 installation at Hamilton’s Ferrybank. Wintec media arts, business and IT students will work together to create an app with the sensor data from the waka project. Sustainable energy options have been researched by Wintec electrical engineering students and next year will see their implementation, using solar and wind solutions.
BackgroundThe multidisciplinary Matariki Interactive Waka project was developed by Wintec tutor and PhD candidate Joe Citizen. Joe envisaged this project as a public art installation that encompassed many of the disciplines and values related to his research.
The seven metre tall interactive sculpture is being built with a stainless-steel skeleton and clad in 3mm corten plate, and will utilise an interactive design that engages with the seven stars of Matariki through LED lighting and ambient soundtracks. The interactive sculpture will be activated by movement and its environmental sensor network will operate at dawn and dusk.
The sculpture will be situated at Hamilton’s Ferrybank, having gained unanimous consent from the Hamilton City Council at both its concept and siting stages. It is a collaborative, consultative, multidisciplinary partnership with Wintec’s researchers, Media Arts, IT and Māori Achievement teams, guided by Wintec kaumātua Tame Pokaia.
Current industry partnerships include Longveld, ACLX, and Taranaki-based MechEng. More than $100,000 of funding has been secured so far, with donations, grants, and in-kind support received from Perry Group, Trust Waikato, WEL Trust, Longveld and Wintec.
Follow the Matariki Interactive Waka Project on Facebook.
Homepage image: Artist's impression, the Matariki Interactive Waka sculpture at Ferrybank, Julian Smith.
Dec 13, 2017 - When pulling up to a traffic light, most drivers get pretty close to the car in front of them, leaving just several feet of space between their bumper and the next. The practice of packing tightly at traffic lights is widely accepted. Traditional thinking says the closer a car is to a traffic light, the more likely that car will be to pass through the intersection before the light turns red again.
Thanks to new research by Virginia Tech College of Engineering professors and students, drivers now have a good reason to dismiss this faulty line of roadway intuition. The results could be useful in Ethiopia, where traffic management is a serious engineering project.
The study, published this month in the New Journal of Physics, used video cameras attached to drone helicopters to capture footage of cars accelerating through a traffic light on the Virginia Tech Transportation Institute's Smart Road. By systematically controlling the packing density of the cars, the researchers discovered that any decrease in distance to the light was completely offset by the time it took for cars to regain a comfortable spacing before drivers could accelerate.
Drivers who pack tightly at intersections do not increase their chances of making it through the light, and tailgating at traffic lights can also lead to more rear-end collisions.
"We varied the bumper-to-bumper spacing between cars by a factor of 20 and saw virtually no change in how much time it took for the cars to pass through the intersection when the light turned green," said Jonathan Boreyko, assistant professor in the department of biomedical engineering and mechanics. "The results mean there's no point in getting closer to the car in front of you when traffic comes to a stop," he said.
The inspiration for the research first came to Boreyko when he was sitting in traffic one day. Noticing that cars had to wait for the car in front of them to regain a safe spacing before they could start moving again, he hypothesized that, contrary to popular opinion, it might actually be better for cars to stop farther apart from each other when idling at a traffic light.
He teamed up with Farzad Ahmadi, a fourth-year Ph.D. student in Virginia Tech's engineering mechanics program and the study's lead author, to investigate.Using 10 volunteer drivers in identical vehicles, the researchers staged a series of experiments at the traffic light on the Virginia Tech Transportation Institute's Smart Road. Drivers systematically lined up at the light in a set of distances ranging from 1.25 to 50 feet, and a drone helicopter hovering overhead captured controlled bird's-eye-view footage of the traffic as drivers accelerated through the light.
Analysis showed that the time required for all cars to pass through remained relatively fixed, give or take about one second, for spacing distances up to 25 feet.
The two researchers used the thermodynamic concept of latent heat, the energy that a system loses during melting or evaporation, to describe what happens to cars stopped at a traffic light. Vehicles are jammed into a "solid phase" at a light and must waste energy "melting" back into a "liquid phase" before they can actually move through the intersection.
Boreyko and Ahmadi wondered if latent heat would have such a dramatic effect on other systems, such as slow-moving pedestrian traffic. Should people waiting in lines space themselves closer together or farther apart in order to move through more quickly?
The researchers set up a second round of experiments in The Cube at Virginia Tech's Moss Arts Center, a highly adaptable theater and laboratory equipped with synchronized cameras. Undergraduate students added a few conditions to their senior design experiments on human crowds to test Boreyko and Ahmadi's hypothesis.
"Latent heat had almost no effect for a line of pedestrians," said Boreyko. "The closer people got to each other, the faster they could empty the line. We realized that people move very slowly, but can accelerate very quickly, which minimizes the lag effect we saw with the cars at the traffic light."
The study's findings suggest that both pedestrians and drivers alike could see considerable benefits when taking a mindful approach to packing density in lines.
"Pedestrians waiting in a line should get as close to each other as possible if it's important for the line to empty quickly," said Boreyko. "But when you encounter a traffic jam or stop at a light, keep a safe and comfortable distance. You can just maintain whatever spacing you had when you were driving at full speed. You won't lose any time, but you'll reduce the odds of an accidental rear-end collision."Ahmadi agreed with Boryeko's conclusion.
"When my father was teaching me how to drive, he told me that to prevent an accident, you should stop so you can easily see the rear bumper of the car in front of you at a traffic light," said Ahmadi. "I've never done that until I analyzed the data of this experiment."
Dec 11, 2017 _ The Ministry of Business, Innovation and Employment says there are no grounds to impose provisional measures to protect steel products makers while it investigates claims subsidised Chinese rivals are damaging the local industry. In August, MBIE launched an investigation into steel reinforcing bar and coil (rebar) from the China after Pacific Steel NZ claimed government-subsidised rebar imports from China are causing material injury to Pacific Steel through price undercutting, price depression and price suppression. Pacific Steel is the sole producer of rebar in New Zealand and is a wholly owned subsidiary of New Zealand Steel Holdings whose parent company is ASX-listed BlueScope Steel.
Dec 8, 2017 - Photos of one of Air New Zealand's Boeing 787 Dreamliner engines which failed this week in-flight show damage to multiple turbine blades, at the rear, suggesting a part broke off and travelled through the engine. That engine, on Tuesday morning's flight NZ99 bound for Tokyo with 282 people on board had to be shut down when it caused the aircraft to shake violently.
Passengers heard clunking sounds and electrical power went out temporarily after takeoff from Auckland airport. The plane concerned, which was the first of the airline's nine Dreamliners to go into service, has since been grounded.
On Wednesday another Dreamliner bound for Buenos Aires also had to turn back to Auckland when problems arose with an engine. That engine did not have to be shut down in flight.
Air New Zealand told Newsroom last night it was "extremely surprised by the two issues experienced this week".
Provided with the photos taken of the NZ99 engine after it landed back in Auckland, a spokeswoman said: "The cause of these incidents is yet to be determined and this is the role of the Transport Accident Investigation Commission. But the damage sustained on Tuesday suggests an engine part has travelled through the engine."
Dec 1, 2017 - Phillip Goundar, New Zealand Diploma of Engineering (Civil) student, placed in the top three in an Engineering NZ competition, earning return flights to the November ‘Engineer your Career’ forum. The second year Ara Institute of Canterbury student from Fiji believes it was his creative vision, background and experience that impressed the judges.
In answering why he chose to study engineering Goundar drew upon his own life experiences. “I originate from a rural village in Fiji called Vatukarasa. Growing up we had a very basic house and no [clean] running water. I had to walk with a two-litre bottle to a family friend’s house as they had a borehole and clean water, so I would fill it up and walk back home. I made several trips every afternoon so we had clean water to drink.”
Experiences such as this make Goundar appreciate the value of engineering. “If I don’t do something correctly there are lives at stake, so that builds pride into what I’m doing. I can see how my work is going to serve the community. I can see the importance of my job, especially after going through all of the Christchurch earthquakes and aftershocks.”
Goundar was one of eight engineering students from Ara who beat out competition from tertiary institutes across the country to attend the Wellington forum. Engineering New Zealand, formerly IPENZ, originally offered fifty forum spots for tertiary students. However, due to the high calibre of entries they decided to offer seventy-two spots.
To earn entry to the forum students had to provide winning answers to two questions: what inspired you to study engineering and what does the future of engineering look like to you?
Twenty-one year old Goundar thinks that in the future the engineering industry will place higher value on safety and innovation. Within his own career, Goundar wants to explore the concept of “designing a material which is lighter than concrete but much superior in strength”.
“The highlight of the whole event for me was to hear that grades are important but it’s a fifty-fifty split between grades and experience. For me personally, I made use of all my opportunities at Ara, not just in class. Ara gave me the platform to speak up and share my ideas. The tutors welcome questions and conversation with the students, and they keep learning engaging. It’s clear that they want you to understand.”
From December, Goundar will start working for BECA as a Civil Engineering Technician. However, since attending the forum he is considering his career pathway and exploring the possibilities of further study. “I appreciated the networking opportunities at the forum to talk with new engineers in the field and hear about the difficulties they face. I also gained a better understanding of how I could move up in the ranks within the engineering industry.”
“My goal is to study the Ara Bachelor of Engineering Degree part-time, or a Bachelor of Engineering through University. Once I have achieved that and gained work experience I want to go on to do a taught Masters. I don’t know if I’ll want to work within the industry for my entire career. One day I’d like to be a lecturer.”
Nov 30, 2017 - Engineering New Zealand Chief Executive Susan Freeman-Greene says everything her organisation has done to raise the bar for engineers has been in the shadow of this tragedy. “Today our first thoughts are for those who lost loved ones in the CTV building. We are very aware of the families’ ongoing grief. “We know that the public wants better ways of holding engineers accountable. We’ve changed our rules so that a member can’t resign to avoid a complaint, and we’ve overhauled our complaints process.
“Last year we introduced a new Code of Ethical Conduct that sets new expectations for engineers.
“Engineers now have an obligation to report potential adverse consequences for people’s health and safety. This means that they must take action if they see something of concern.
“For example, if they see potential design flaws in a building under construction, or poor construction practices that threaten health and safety.
“And if an engineer suspects another engineer has significantly breached the Code, they must report this.
“On 1 October, Engineering New Zealand introduced a new membership pathway for our 20,000 members. All members must now pledge every year to uphold the Code of Ethical Conduct and commit to ongoing professional development.
“We have strengthened the Chartered Professional Engineer assessment process for structural engineers to include more specific and targeted assessment.
“But we would like to see changes to the way engineers are regulated. Engineering New Zealand supports the task-based licencing of engineers for safety-critical work. This means restricting safety-critical design to engineers specifically licensed to do this work.
“As well as structural engineering, we’d like to see this kind of regulation extend to any safety-critical work; for example, fire, geotechnical and food-process engineering.
| Background: Complaints relating to the CTV building tragedy
We received complaints about David Harding from MBIE’s Chief Engineer and a group of victims’ families.
Our Disciplinary Committee found that Mr Harding had breached our Code of Ethics.
Towards the end of this process, he resigned.
Because he was no longer a member, the Disciplinary Committee had no power to make any orders against him, but we made the decision against him public.
We received complaints about Alan Reay from MBIE’s Chief Engineer and a group of victims’ families.
Dr Reay resigned as a member in February 2014, while the complaints process was underway.
The timing of his resignation meant we no longer had jurisdiction over Dr Reay. So the complaints process was stopped.
In March 2015, the Government sought a judicial review of our decision to stop the complaints process. The judicial review is ongoing and a date for the substantive hearing hasn’t been set. In the meantime, we have changed our rules so that a member can’t resign to avoid a complaints process.
| An Engineering New Zealand release || November 30, 2017 |||
Nov 30, 2017 - A major tourist attraction that will include a cable car, toboggan rides, zip wire, as well as a restaurant and event venue on Kilvey Hill in Swansea has taken a step forward. Board directors of New Zealand-based Skyline Enterprises have given the green light for the company to start the detailed design process and begin legal discussions for the attraction the will overlook Swansea Bay.
Representatives from Skyline Enterprises will now work with Swansea Council to move the deal forward and get it approved.
Once an agreement is in place, Skyline Enterprises will start working towards its planning application.
Should the scheme go ahead it will be funded entirely by private money, with no funding required from taxpayers.
Cllr Robert Francis-Davies, Swansea Council's Cabinet Member for Culture, Tourism and Major Projects, said: "This is great news for Swansea, for Swansea's tourism industry and for Wales.
"Thanks to a 'Team Swansea' approach and the backing of a number of local businesses who have been supportive of the Skyline proposal, we were able to convey to Skyline Enterprises our enthusiastic support for the scheme during their recent visit.
"This decision is a great vote of confidence in Swansea as a tourist destination and builds on the great work being done through the City Deal and our bid to be the UK's City of Culture in 2021."
Skyline Enterprises already runs two resorts which feature cable car rides and other attractions in New Zealand, as well as luge rides in Canada, South Korea and Singapore.
The cable car attraction set for Swansea would be the company's first outside New Zealand.
Representatives of the company have been to Swansea twice in recent months to check out the potential of Kilvey Hill as a tourism hotspot capable of attracting tens of thousands of visitors a year.
The latest visit included meetings with Swansea Council and major local businesses at the Liberty Stadium to advance Swansea's case for the attraction, which would further build on plans to regenerate the River Tawe corridor.
Cllr Rob Stewart, Swansea Council Leader, said: "Kilvey Hill, standing 193 metres tall, enjoys spectacular views over Swansea Bay, the marina, SA1, the Liberty Stadium and the historic Hafod Morfa Copperworks site.
“It's been an underused resource, and has huge potential to be transformed into a fun visitor destination for local people and hundreds of thousands of visitors a year.
"We were determined to do all we could to help bring this project to Swansea because it would also attract additional investment and benefit local businesses by generating more spending and supply chain opportunities."
Geoff McDonald, Skyline Enterprises chief executive, said: "Skyline Enterprises is very excited about the potential opportunity to partner with the Swansea community to create what we believe will be a significant and vibrant attraction for the area.
“We are encouraged by the enthusiasm and interest in our gondola and luge operation, and look forward to on-going discussions."
The cable car attraction would add to the work Swansea Council and Swansea University are continuing to do to breathe new life into the historic Hafod Morfa Copperworks site.
With support from the Welsh Government, Cadw and European funds, progress on site has included clearing vegetation, stabilising buildings at risk, improving access for visitors, community archaeology fieldwork, new pathways, an audio-visual trail and new information panels.