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What a year it has been.
2015. The year I started "really" doing brush calligraphy.
I say "really" because my first experience with the brush calligraphy pen was more than a year ago. However, it wasn't until January 2015 that I really got serious and passionate about the brush pen.
Fitting for my first post in the new year, here are 10 things I have learned after a year of brush calligraphy…
On Learning
- Brush calligraphy is "real" calligraphy. I used to think that pointed pen was the only "real" calligraphy. I actually didn't like the brush pen when I first tried it! It turns out that calligraphy really refers to the thick and thin variations formed when handwriting letters. So say it with me, loud and proud, "Brush calligraphy is real calligraphy!"
- There is no such thing as overnight success. While it is easy to see great, elaborate works of art and thing that you will never get there, you are wrong. The thing is, you COULD get there. And you WOULD get there. It just won't happen overnight.
- It's about the journey, not the destination. I found my biggest success and improvement when I stopped worrying about the results. Instead of fixating my efforts on the final product, I started to just enjoy the process, complete with the spills, smears, and spelling errors. The most fulfillment comes from learning and growing.
- The creative community is real and strong. While you may feel alone in your creative journey, like no one believes in you or supports you, or you can't find anyone to reach out to about your challenges and struggles, think again! The best place I can point you to is social media. For me personally, I have found so much support on Instagram connecting with calligraphers from around the world. It is amazing engaging with others who share in your same passion. Don't be shy. Say hello, ask questions, and support others.
On Supplies
- Not all brush pens were created equal. As I have explained in the past, brush pens can vary depending on their size, thickness, flexibility, firmness, and ink. Try as many as you can. You never know which ones will be your favorite (or least favorite!)
- Rhodia pads are DA BEST. PERIOD. I don't mean to play favoritism. But this is an exception. Rhodia pads are my FAVORITE. They are so smooth and perfect for gliding your pen across the page with ease. They are perfect for protecting your brush pens from fraying or getting worn out too fast.
- Portability makes brush calligraphy so easy. I love that I can just throw a pen or two, plus a small Rhodia pad in my bag and go. Getting set-up is so easy because the ink is already loaded into the pen, and just about any smooth, non-porous paper will work!
On Teaching
- The more you teach, the more you learn. I learn so much as I teach. I learn because I have to break concepts and processes down to the very core. By doing so, I recognize faults in my own self and find out that something that seemed to make sense in my head, doesn't quite translate well for someone else. By teaching, and learning as I teach, things come full circle for me. As I teach what I know, I am able to learn more about myself and about brush calligraphy, and then go and share those lessons with others.
- What's good isn't always popular. What's popular isn't always good. Sometimes trends tempt me to drop everything I'm doing and follow them. But in my experience, sticking to one thing is exactly what will get you further than ever. You just follow the crowd and chase the shiny object. Focus on what you do well, even if it's not the "cool" thing. Because guess what is cooler than being trendy? Being an expert.
- Just because you don't know everything, doesn't mean you cannot teach. In fact, you should teach as soon as possible. I have always felt that I needed to be "ready" to teach. I wanted to know everything and be the best before I could host any kind of a workshop. But after listening to the wise words of successful entrepreneurs such as Sean McCabe and Jeff Goins, I realize that I should have started teaching sooner. The minute I had something to share and teach to at least one other person, I should have began dumping all that I had to offer to that one person. Because inevitably, I learned more and soon learned so much that others don't know at all. But better late than never. With Spring 2016 around the corner, I am finally committed to hosting local workshops and building my very first online class.
When I first started this blog, I wasn't quite sure how far it would go. I simply wanted a little corner of the Internet in which I could share my experiences with calligraphy, showcase my work, and possibly receive feedback from others. But my blog has grown into something so much more than a compilation of words and photos. It's now my home for inviting others into the wonderful world of brush calligraphy, enlightening them with my very best tips and tutorials, and promoting the right kind of practice so that others can find success in their own journeys.
What you can look forward to in 2016
Bigger and better things! While this past year has been filled with tons of great stuff, I want to make 2016 even greater. You can look forward to:
- Continued blogging and videos. I love sharing what I know and giving it away FOR FREE. Yes, I will be putting out paid content in order to sustain my efforts of blogging and videos, but I will always have this blog and my YouTube channel where you can access plenty of content at no cost. Judging by the overwhelming feedback I have been receiving lately, many of you out there want more videos and tutorials!
- ABC Challenge. On Instagram, I host an account called @handletteredABCs. Beginning January 3, 2016, we have challenged participants to write a letter a day until we complete the entire alphabet. Check out the challenge post here, as well as the amazing work that has already been created here! This is the perfect way to put together the basic strokes I have reviewed in the past eight weeks. Hope you'll join the fun!
- Classes. As I mentioned above, 2016 is the year I host local, in-person workshops and online classes. I want to finally go deeper with you and really teach the fundamentals of brush calligraphy to as many students as I can. Stay tuned for dates and registration!
Thanks for a great year!
I hope you enjoy this short video I prepared. I am used to showing only my hands in my videos, so this was new and exciting (and slightly terrifying) for me!
~ ~ ~
It's your turn! Tell me in a comment below:
What are somethings you learned in 2015?
What do you hope to accomplish in the new year (2016)?
What is one thing you are looking forward to, here on Pieces Calligraphy?
~ ~ ~
P.S. If you liked this post, please share it with a friend!
P. P. S. If you haven't already done so, subscribe to my blog below so you get my posts directly in your inbox!
Follow me on Instagram: @piecescalligraphy
Watch more videos on YouTube: piecescalligraphy


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Excessive, uncontrollable sweating of the hands or palms, is called palmar hyperhidrosis. This medical condition is an extremly stressful, embarrassing, and confidence-wrecking problem. From ruined paperwork to slippery handshakes, sweaty palms can negatively impact your social life, education, and career.
It's proven and published that palmar hyperhidrosis has the most significant negative impact on patients' lives of any dermatologic condition.
But there are treatments available, the treatments work, and you have a number of choices.
The first line-of-defense against sweaty palms is an antiperspirant. That's right, you CAN use antiperspirants on your hands. Antiperspirants are non-invasive, topical (applied on top of your skin), and available in a number of different strengths including "regular" over-the-counter products, "clinical strength" over-the-counter products, and prescription products. You may have already tried the mildest formulations ("regular" over-the-counter products) and likely didn't get much relief. The next step is to try a stronger formulation. Learn about key choices on our Fan Fave products page. All companies listed on the Fan Fave products page proudly support the International Hyperhidrosis Society, have good customer reviews and offer global shipping.
But before you work your way up to even stronger formulations (prescriptions) we suggest that you make sure you are using products to optimize their effectiveness and–importantly–minimize irritation. In fact, how you use antiperspirants is so important, we have a whole section dedicated to it, but the most important tidbits are:
- Apply antiperspirants at night before bed
- Apply to completely dry skin
- Never wrap or occlude your hands when you have antiperspirants on them. Doing that is a sure-fire way to seriously irritate your skin.
If antiperspirants don't give you the palmar hyperhidrosis relief you need, your next option is iontophoresis. When the right device is used, and used correctly, iontophoresis has been proven to have impressive success rates (81% reduction in sweating according to a published study) for people with sweaty palms. Read all about it on our iontophoresis page, but here's a summary:
- A medical device is used to perform iontophoresis in a doctor's office and/or at home.
- The device utilizes pans of water to conduct a mild electrical current through the skin's surface.
- It's not entirely understood how or why iontophoresis works, but it's believed that the electric current and mineral particles in the water work together to microscopically thicken the outer layer of the skin, which blocks the flow of sweat to the skin's surface. Once this sweat output is blocked or interrupted, sweat production on the palms and soles is, often suddenly and dramatically, "turned off".
- Your doctor can write the prescription for the device which you then provide to the manufacturer when you are ready to purchase your own.
- Always mention the International Hyperhidrosis Society when you place your order to be certain you are given the best price and service. You can also check our Fan Fave Products page to see if there are any coupon codes available.
Another treatment option for sweaty palms is Botox (also known as onabotulinumtoxinA). An experienced medical professional can inject Botox into your palms to dramatically reduce sweating. Effects are lasting (about 6 months) but the injections can be painful. To help make the injections more comfortable, experienced medical professionals are turning to a simple icing and/or vibration technique, but be aware that discomfort during injections is a potential drawback of Botox treatment for palmar hyperhidrosis.
The use of Botox for the treatment of hyperhidrosis is most effective when performed by a healthcare professional who has received special training from the International Hyperhidrosis Society and who has experience with the procedure. To find a physician, nurse practitioner (NP) or physician assistant (PA) in your area who is familiar with hyperhidrosis treatments, use our Physician Finder. And if you want to find one who has attended our Master Class in Hyperhidrosis, look for the "IHhS-Educated" notation in the Physician Finder search results. You can also use the Advanced Search button to search for only those who have received training by the International Hyperhidrosis Society.
While most people find that antiperspirants, iontophoresis, Botox injections, or a custom combination of these are enough to manage excessive hand sweating, there are those who seek a more definitive course of action. If less invasive treatments have proven to be insufficient, endoscopic thoracic sympathectomy (ETS) may be considered as a last resort. ETS has significant risks associated with it, however, particularly a side effect called compensatory sweating (irreversible excessive sweating on large areas of the body) and should only be used in extreme cases after a thorough trial of all other options.
As of now, the options for treating palmar hyperhidrosis are not ideal. That's why we continue to advocate for hyperhidrosis research and donations. Both are vital if we are to finally find a safe cure for palmar hyperhidrosis.
We hope that you find the information on this site helpful and inspiring as you search for the best way to manage your sweating problem. For updates about new hyperhidrosis research, the latest hyperhidrosis treatments, and daily management tips, be sure to sign up to get our blog emails. We also have an extensive library of hyperhidrosis articles from peer-reviewed medical journals, so you can see where we get our facts, and you can share reliable medical data with your physician.

subset: commoncrawl


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For remembering Ronan. You all are insanely amazing. I have literally received thousands of emails, tweets, texts, phone calls, blog comments, etc… about Ronan. I hope you all know how much it means to me. Thank you for remembering my sweet boy. I appreciate each one of you, so very much. If I could, I would kiss the ground you walk on and sprinkle you all with glitter. Thank you for helping this broken-hearted mama, get through this month of May. And an extra special thanks to my very amazing friends who are like family. The best kind of family to have. I love you all and consider myself so lucky to have you all surrounding me. Best sisters ever.
I love you all to the moon and back. Ronan does, too.
Thank you to one of my little Twitter followers for the picture above. So very sweet.


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Gay men say Texas bar kicked them out for dancing
VICTORIA, Texas (AP) — A gay couple says they were asked to leave a South Texas nightclub because they danced together to country music.
The Victoria Advocate reports Wednesday that a manager at the Cactus Canyon nightclub says the pair were asked to leave because they were disruptive. Robert Dillender says the club is obligated by the Texas Alcoholic Beverage Commission, which issues liquor licenses, to maintain the peace. The club is now reviewing how it interprets that policy.
But 21-year-old Justin Meyer says he and his partner were told Saturday night they had to leave because the club had a policy against two men dancing together to country music.
The American Civil Liberties Union of Texas says it is reaching out to the couple to help them battle discrimination.


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ATHENS, Ga. (AP) — South Carolina credits its defense for its growing collection of double-digit Southeastern Conference wins.
Against Georgia, that defense was overwhelming.
AJ Lawson scored 20 points and South Carolina held Georgia to one field goal for the first 14 minutes to earn a runaway 75-59 win over the struggling Bulldogs on Wednesday night.
South Carolina (15-9, 7-4 SEC) earned its seventh straight win in the series, including its fourth straight in Athens.
It was South Carolina's third straight win in which it held its opponent under 60 points.
"We feel good right now on defense because we all help each other," Lawson said. "If one person gets beat he gets help on the back side."
South Carolina had 10 steals, including three by Lawson.
The Gamecocks, who have won five of their last six games, had four players score in double figures. Freshman Jermaine Couisnard had 14 points.
South Carolina led 27-5 before the Bulldogs' second field goal with less than six minutes remaining in the first half.
"They just outplayed us in every aspect of the game," said Anthony Edwards, who led Georgia with 16 points. "Every aspect of the game. That's all I can say."
Georgia (12-12, 2-9) is 13th in the 14-team SEC and has lost seven of its last eight games, including three straight.
South Carolina coach Frank Martin said the dominant start against Georgia was a carryover from a 75-54 home victory over Texas A&M on Saturday.
"Obviously the way we started the game defensively was kind of piggybacking the way we played the last game defensively," Martin said.
Of the Gamecocks' seven conference wins, five have come by double figures. Their only SEC wins by fewer than 10 points were against Kentucky and Arkansas.
"We've played good ball for a while," Martin said, adding his team took consecutive road wins at Clemson and Virginia in late December.
One game after the Bulldogs topped 100 points in a 105-102 overtime loss to Alabama, they suffered their lowest scoring first half of the season. South Carolina led 38-20 at halftime, thanks to the Bulldogs' turnovers and poor shooting.
The 59 points matched Georgia's low for the season in lopsided losses to Mississippi State and Arizona State.
Rayshaun Hammonds finally gave Georgia its first field goal with 12:50 remaining in the half. The Bulldogs then suffered another seven-minute field-goal drought before Tye Fagan's basket with 5:40 remaining in the half.
South Carolina stretched its lead to 23 points, 49-26, on a three-point play by Couisnard early in the second half.
Georgia built some offensive momentum midway through the half. Donnell Gresham's four-point play cut the Gamecocks' lead to 55-41. Couisnard answered with a quick 3-pointer and South Carolina pushed the lead back over 20 points.
South Carolina: The Gamecocks, who had four players score in double figures, were dominant in almost every category when winning their second straight game since losing starting F Justin Minaya to a left thumb injury. South Carolina outrebounded Georgia 45-33, including nine by Alanzo Frink, and outscored the Bulldogs 40-22 in points in the paint.
Georgia: Coach Tom Crean identified his team's poor on-ball defense as a glaring weakness following the high-scoring loss to Alabama. This loss to the Gamecocks showed there are other glaring deficiencies, including on offense where 19 turnovers were a near-constant problem. South Carolina took a lopsided 25-4 advantage in points off turnovers. The Bulldogs' previous low for first-half points was 24 against both Texas A&M and Auburn.
Edwards, the nation's top-scoring freshman with his average of 19.7 points per game, missed each of his seven 3-pointers. Edwards wasn't the only Georgia player to struggle with outside shots. Georgia made only 3 of 24 3s.
Former Georgia wide receiver Mecole Hardman gave Georgia fans a rare reason to cheer when he was introduced during a timeout and recognized for his role on the Kansas City Chiefs' Super Bowl championship team. Georgia officials again appealed to football fans when coach Kirby Smart's six signees who enrolled in school early were introduced during another break.
South Carolina returns home to play Tennessee on Saturday night.
Georgia will try for its second win over Texas A&M this month when it visits the Aggies on Saturday.
More AP college basketball: https://apnews.com/Collegebasketball and https://twitter.com/AP_Top25


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EVERETT — The Washington Stealth are trying to move from being consistently inconsistent to consistently good.
They took a big step in the right direction Sunday at Comcast Arena with an 11-8 victory over the Minnesota Swarm.
With the victory and Calgary's loss to Edmonton on Saturday, the Stealth (6-4) strengthened their hold on first place in the National Lacrosse League's West Division and in the process evened the season series with the Swarm.
Washington fell behind with 10:15 to play in the first quarter when Kiel Matisz scored the first goal of the game, but the Stealth bounced back quickly.
Defenseman Jeff Moleski scored the Stealth's first goal of the night when he grabbed a rebound off his own shot and put a second shot past Tyler Carlson to tie the score. The Stealth took the lead when Lewis Ratcliff scored his only goal of the night with 5:46 to go in the opening quarter.
The Stealth never trailed the rest of the way.
The Stealth took control of the game in the second quarter, thanks to forward Athan Iannucci, who scored three straight goals in the first 3:20 of the period.
"That's what I expect from myself every game if possible," Iannucci said. "I've been feeling good. I feel like I've been developing a good chemistry with (Rhys Duch) and some of the other guys on the offensive side too, so yeah, it feels good."
Iannucci finished the game with six points, scoring four goals with two assists.
Goals were at a premium with Carlson and Stealth netminder Tyler Richards at the top of their games, but Iannucci and Stealth forward Brett Bucktooth both had big games.
Bucktooth matched Iannucci with six points on three goals and three assists. He scored the Stealth's only two goals of the fourth quarter to help put the game away.
"The ball just found us and you just have to make your shots," Bucktooth said. "Fortunately, I was able to find the net."
The Stealth's 11 goals were more than enough with Richards in goal. He saved 43 of the 51 shots he faced, continuing his recent string of elite play.
"It's great," Iannucci said of Richards' play. "There are times where you are like, 'Oh here comes a goal.' And then he makes a save. Now we are starting to get to the point where we almost expect it. One goes in and we are like, 'Come on, you are supposed to be impenetrable here.'
"He's great confidence for our defense and our offense. Everyone can play a little more relaxed. As long as this guy stays out of the penalty box."
Iannucci was joking with Richards, who was standing nearby, about picking up his second penalty in as many games. This week it was a two-minute penalty for roughing. Minnesota's Jay Card went for a shot and landed in the crease. With the ball still in play, Richards kept his focus on the ball though he had Card straddled to the point he couldn't move.
"I kind of take it personal when guys are diving at my knees," Richards said. "It's my livelihood on the line and sometimes I get a little fired up when guys dive through and don't really make the effort to avoid me."
After the game Richards had a sense of humor about the play.
"The rule is, if there is a player in the crease they can't score a goal," he said. "So I was just trying to keep him in there for as much of the 30 (second shot clock) as possible."
The victory gives the Stealth consecutive wins for just the second time this season. And head coach Chris Hall was satisfied with his team's play after the game.
"We played very well," Hall said. "Even when Minnesota came at us, I think we held up pretty well. T-Rich (Richards) was big of course and we got a couple of key goals from Bucktooth late, so I'm pretty happy obviously."
Aaron Lommers covers the Washington Stealth for The Herald. Follow him on twitter @aaronlommers and contact him at firstname.lastname@example.com.
Stealth 11, Swarm 8
Minnesota 1 2 3 2 — 8
Washington 2 5 2 2 — 11
1st Quarter — Scoring: MIN — Matisz Goal (Hass) 4:45; WAS — Moleski Goal 6:40; WAS — Ratcliff Goal (Iannucci, Bucktooth) 9:14. Goalie Changes: None.
2nd Quarter — Scoring: WAS — Iannucci Goal (Duch, Ratcliff) 1:03; WAS — Iannucci Goal (PP) (Bucktooth, Duch) 1:45; WAS — Iannucci Goal (Grimes) 3:20; MIN — Card Goal (Tao) 5:10; WAS — Hill Goal (Bucktooth, Duch) 11:44; WAS — Bucktooth Goal (Smith) 11:51; MIN — Bilic Goal (MacIntosh) 12:00. Goalie Changes: None.
3rd Quarter — Scoring: MIN — MacIntosh Goal (Crawford, Benesch) 3:21; WAS — Duch Goal (Ratcliff, Beers) 4:11; MIN — Gilbert Goal (Sorensen) 6:43; MIN — Crawford Goal (Benesch, Jackson) 12:08; WAS — Iannucci Goal (Hill) 14:16. Goalie Changes: None.
4th Quarter — Scoring: WAS — Bucktooth Goal (EA) (Iannucci, Duch) 0:30; MIN — Crawford Goal (Downing) 3:37; MIN — Jackson Goal 3:51; WAS — Bucktooth Goal (Duch) 10:16. Goalie Changes: None.
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"What woman only wears only one outfit for 60-plus years?" asks DC Comics writer J. Michael Straczynski who was tasked with giving the aging superhero Wonder Woman a new, darker back story to shake up sales — plus her first big wardrobe upgrade since 1941. Gone is the skimpily patriotic bustier-and-hot-pants look. In its place: A stripeless combo of "urban-hip" black leggings, low heels, and a dark blue jacket with "I mean business" sleeve-rolling. (See a slideshow of Wonder Woman through the years.) Comic aficionados are split on the sensible new look:
The revamp is a "super bummer": I know superhero makeovers always trigger a backlash, says Lauren Beckham Falcone in the Boston Herald, but come on: This evolution into a "waif with implants and a credit card at Forever 21" isn't progress. "When Wonder Woman goes from brazen superpower to Bratz doll in one brushstroke, the bad guys win."
"Wonder Woman's new look a super bummer"
DC had to take some action: Wonder Woman occupies a curious position as "the most popular superhero no one seems to like very much," says Stephen Totilo in Kotaku, so it's not surprising DC's trying to shake her up. Though this look is "nobly," less trashy, unpopular costume changes don't tend to last very long. "Electrified Blue Superman" was gone in a year.
"Wonder Woman costume modified so that it makes sense?"
This is exactly what Wonder Woman needed: It's way past time for Wonder Woman to get a pair of pants, says Robin Givhan in The Washington Post. Now she's "a glamorous athlete" with authority instead of "an unusually muscular Miss America who happens to fight crime." Bonus: By shedding her flag themes, "she has shrugged off parochialism to become an international sophisticate."
"From star-spangled briefs to skintight pants, Wonder Woman is still a wonder"
Making her "dowdy" doesn't make her stronger: Wonder Woman's new outfit has "a certain admirable practicality," says Mary Elizabeth Williams in Salon, but that's not the point. "It's never just about saving the world — it's about looking fabulous doing it," and trading Wonder Woman's "unabashed flashiness" for a less revealing getup is a step backward. "What's super about a jacket? Nothing."
"Wonder Woman's dowdy fashion makeover"


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Flowers and mementos left by supporters adorned Joe Paterno's gravesite today, a year after the longtime Penn State coach's death, while at the spot where a bronze statue of him used to stand, a makeshift sign of cardboard flapped in a cold wind.
"Joseph Paterno. Always remembered. Always a legend," read the sign outside Beaver Stadium and attached to a tree with white wire.
The Hall of Fame coach died of lung cancer Jan. 22, 2012, at age 85. Besides the bouquets and signs, at least 150 supporters also marked the anniversary of his death with a candlelight vigil on a frigid evening at a downtown State College mural that includes a depiction of Paterno.
He died more than two months after being fired in the frantic days following the arrest of former assistant coach Jerry Sandusky on child molestation charges in November 2011. His legacy remains a sensitive topic for groups of alumni, former players and residents.
"I definitely think that everything that has happened isn't at all indicative of the kind of man that he was," said Bridget Beromedi, 32, of State College, who wore a shirt with Paterno's image. She held up a sign that read "JoePa. Legends never die."
She added that Paterno's role in the scandal "got totally overblown because of his name. He got an unfair deal."
Organizers lit candles inside white or blue paper bags, many inscribed with handwritten messages from supporters. The gathering slowly broke up within 45 minutes after mural artist Michael Pilato thanked attendees, several of whom wore "JVP" buttons on their winter parkas.
A family spokesman said the Paternos wouldn't take part in public gatherings today.
A year ago, the campus was flooded with mourners. Commemorations were much smaller this year with temperatures in the teens.
Supporters like Dan Hamm, a freshman from Williamsport, have said Paterno's 46-year career as a whole should be taken into consideration, including his focus on academics.
"We wanted to pay our respects. We wanted to celebrate who he was as a person," Hamm said after visiting Paterno's grave at a State College cemetery.
Then, nodding his head in the direction of Paterno's adorned gravesite, Hamm said, "You can see here that Joe Paterno was Penn State, and Penn State will always be Joe Paterno."
Former FBI director Louis Freeh released findings July 12 in the school's internal investigation of the scandal. Paterno's reputation was tarnished after Freeh accused the coach and three former school administrators of covering up allegations against Sandusky.
The retired defensive coordinator has been sentenced to at least 30 years in prison after being convicted of 45 criminal counts. Prosecutors said allegations occurred off and on campus, including the football facility. Sandusky has denied the allegations.
On July 22, Penn State removed Paterno's statue, which was a gathering point for mourners last January. The next day, the NCAA reacted with uncharacteristic swiftness in levying strict sanctions including a four-year bowl ban, strict scholarship cuts and a $60 million fine.
Paterno was also stripped of 111 victories, meaning he no longer held the major college record of 409 career wins.
Paterno's family and the three administrators have vehemently denied Freeh's allegations, along with denying suspicions they took part in a cover-up. Also, Paterno's family has been planning what a spokesman has called a comprehensive response to Freeh's findings.
But today, the family remained in privacy. A delivery man dropped off flowers at the Paternos' modest ranch home in the afternoon, walking past a sign staked to the snow-covered lawn.
The sign read in part, "Thank you Joe! Thank you Sue!", referring to Paterno's widow. "RIP JoePa ... 409 forever."
The crowd at the vigil broke up after Pilato spoke for about five minutes. "If Joe Paterno is looking down on us tonight," he said, "we all know that he is not concerned with that number (409), but with the people connected with those wins.
He also said that Paterno's role was sensationalized in media coverage and by a rush to judgment. Pilato ended his talk by starting a chant of "Joe Paterno!"
Hamm's friend, fellow freshman Nick Bucci, said he felt his school handled the scandal well overall, given the extent of the fallout, with some exceptions.
At some point, Bucci said, the school should honor Paterno. He referred to one suggestion that dated back years before Paterno's death, of naming the field at the stadium after the coach.
But Bucci advocated for perspective.
"A day like today, those emotions might be high," said Bucci, of Dayton, Md. "I don't think now is the time to do it. I think you have to wait."


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Slightly amazed but not surprised to watch the news coverage of the Hyperloop and seeing it run about 75% negative so far – people calling it "out there" and questioning the cost projections, the safety, and everything else that was detailed.
The skeptics and the talking-heads that are out there mocking it, are frankly representative of a relatively new type of attitude that seems to want to kill big ideas and dreams before they even have a chance.
I spoke to a retired physics professor a few months ago and he said the biggest difference he saw in students in the 60s and 70s VS today was that the moon shot and other big projects gave people the confidence that any idea was possible. And that today there was a quicker instant-default-reaction of cynicism and doubt to anything really big or seemingly "far fetched".
I personally have no idea if the Hyperloop will ever succeed or even get a green light to be built.
What I do know is that I'm super excited that someone with a pretty amazing track record (PayPal, Tesla, Space X) is tackling transportation and looking to leapfrog the current train system which is dated, expensive, and just not that exciting. And we should give these people a chance to take a few swings and see what they can come up with before every arm-chair expert chimes in on why it's not possible. From the conference call follow-up that he held, sounds like he may now build a mini-prototype just to show everyone that it can work.
So my humble $.02 is that we need more people thinking like this, not less — and we need more aspirational projects that open people up to the near limitless possibilities of what we can build and solve.
I'm also a big believer that teams in Silicon valley will have a much better chance of tackling these problems than the traditional companies in the transportation industry that have been relatively stagnant for years now, mainly focused on cost reductions. Reminds me of a Steve Jobs quote:
"The people who built Silicon Valley were engineers. They learned business, they learned a lot of different things, but they had a real belief that humans, if they worked hard with other creative, smart people, could solve most of humankind's problems. I believe that very much."
And I always keep this quote in mind:
"First they ignore you, then they laugh at you, then they fight you, then you win." — Mahatma Gandhi
If you haven't listened to the Elon Musk conference call outlining it all, here is the clip:


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FreeBSD Manual Pages
KCON(1) FreeBSD General Commands Manual KCON(1) NAME kcon -- pcvt keyboard control and remapping SYNOPSIS kcon [-d delay] [-l] [-m map] [-o] [-p] [-R] [-r rate] [-s] [-t+/-] [-x] DESCRIPTION The kcon utility is used for controlling all aspects of keyboard configu- ration for the 'pcvt' video driver. The available options are: -d delay Specifies the delay after which the last key entered will be repeated by the Keyboard. Valid values are 0..3 corresponding to delays of 250, 500, 750 and 1000 milliseconds. -l Displays the current keyboard map in use by the driver. -m map Specifies the map entry to be searched in the keyboard capabilities database keycap. The database is searched for the entry and if found, the mapping is loaded and is used in the driver from then on. -o Switches display of control codes to octal in the listing of the current map. To be used in conjunction with the -l option. -p Uses 'pure' output when listing - the Escape character is displayed in either octal or hexadecimal and not as 'ESC'. To be used in conjunction with the -l option. -r rate Specifies the character repetition rate. Valid argument values are 0...31 corresponding to rates of 30 characters/second ... 2 charac- ters/second. -R Reset the Keyboard. -s Displays the current settings of the rate and delay values. -t +/- Specify this option to enable (+) or disable (-) the repetition of keys. -x Switches display of control codes to hexadecimal in the listing of the current map. To be used in conjunction with the -l option. This is the default behaviour. FILES /usr/share/misc/keycap.pcvt Keyboard capabilities data base file if nothing else was chosen during installation. /dev/console Keyboard raw device. EXAMPLES The command ``kcon -m gb'' loads the entry 'gb' from the keycap file into the keyboard to switch to a british keyboard behaviour. The command ``kcon -r 0 -d 0'' switches the keyboard to emit characters at a rate of 30 characters per second after a key has been held down for 250 milliseconds. SEE ALSO keycap(3), keycap(5) BUGS The kcon utility detects several inconsistencies in the keycap database. In case of errors kcon exits with an error message. If this happens, the keyboard may remain in an undefined state. To recover from such situa- tion, execute ``kcon -m default''. FreeBSD 6.2 March 27, 2000 FreeBSD 6.2
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When your world crashes down
When they all say you're out
When your body is broken
I will rise.
I will return.
And I will be undefeated.
Nick Renshaw is the golden boy of British rugby. When a serious injury threatens his career, he starts to spiral downwards, a broken man.
Feeling abandoned and betrayed by those closest to him, he fights to restart his life. Maybe there's someone out there who can help him. Maybe he can find his way back toward the light. Maybe … not.
Dr. Anna Scott might be the one person who can help Nick, but she has her own secrets. And when Nick's past comes back to haunt them both, the enigmatic doctor is more vulnerable than she seems.
Broken and betrayed, the struggle to survive seems intolerable. Who will give in, and who will rise, undefeated?
It's been noticed," she began carefully, "that you're not engaging with the team or … or with me during my teaching sessions."
His lips pressed together and his scowl deepened.
"Look, I know this is all kinds of awkward," she sighed, "but your behaviour is already giving Sim concerns. It's making him wonder about your commitment to the team."
Nick exploded, his anger filling the space as he leapt to his feet and began to pace up and down, hands scrubbing over his face roughly.
"He's questioning my commitment?! I train harder than anyone! I train on my off-days," he spat furiously, his voice tight with emotion.
"I'm out there, slogging my fucking guts out harder and longer than anyone else during practices!"
"I've fought to come back from injury. I'm fit! I'm ready! I…"
"NICK!" Anna slapped her hand down on the massage table. "Will you listen to me!"
His jaw snapped shut and his stormy eyes narrowed on hers.
"Sim didn't see that commitment during my sessions."
"And we both know why that is," he sneered. "You don't want any commitment from me."
Anna's eyebrows shot up and Nick looked as though he was already regretting his words. He took a deep breath and looked away while Anna chose her next words carefully.
"You assured me that you could be professional and…"
"Yeah, well excuse me if seeing you again is fucking with my head! Not everyone can be as cold and calculating as you!"
She knew she deserved his anger, but her own frustration was rising to meet his. The volcanic pressure inside started to build, searching for an exit, searching for weakness.
"I cannot have any sort of relationship with a client!" she hissed, her body rigid. "You know that!"
"Didn't stop you before," he taunted.
"You weren't a client then," she choked. "But you're right—I should have stopped. Oh boy, am I regretting it now!"
And she tossed her clipboard onto the table, pointing a finger in his face.
"Are you trying to ruin this for me? Is that what this is? Your ego can't bear it, so you're going to make sure I lose this contract? Or maybe ruining my reputation forever will settle the score. You tell me, Nick! What do you want from me?"
She was breathing rapidly, and two points of colour marked her cheeks in an otherwise chalky complexion.
He spun around, prowling toward her, his jaw clenched, his hands balled into fists.
"What do I want?"
You can find my review of this book here:
Undefeated – a review
Currently he is a Personal trainer living in Cheshire, and has an online fitness program: Fear Nothing Fitness.
I enjoy watching surfers at my local beach, and weaving stories of romance in the modern world, with all its trials and tribulations.
It's been the best fun working with Stu on this story. And yes, he did think about joining the Marines once.


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This article is more than 1 year old
Western Digital profits down despite revenue rise
Declining drive prices ate into income
Revenues for disk drive industry leader Western Digital's third fiscal 2013 quarter rose 24 per cent to $3.8 billion – compared to $3 billion a year ago – but profits fell 19 per cent. It's a hard life in the disk drive business.
The previous quarter's revenues were $3.8 billion too; no change there, then. Third-quarter profits of $391 million compare poorly to the year-ago quarter's $483 million, but Thai-flood-induced disk price rises are now long gone.
Profits were up sequentially; the second fiscal 2013 quarter's profits were $335 million.
"Overall industry demand was in line with our expectations. In our business, we saw strength in enterprise, stable performance in client and consumer electronics, and some anticipated seasonal softness in Branded Products," WD CEO and president Stephen Milligan said in a statement.
WD shipped 60.2 million drives in the quarter. By comparison, it shipped 59.2 million in the second quarter and 44.2 million in the third quarter of fiscal 2012, back before WD acquired HGST.
We charted the rise and fall in WD's average selling price for its hard drives and here's the graph:
One thing that will affect this is that the average capacity of 3.5-inch and 2.5-inch disk drives is trending up. However we'd, need to know the split between 3.5-inch drive numbers and 2.5-inch drive numbers to understand this effect better, and we don't have that data.
Interestingly, the ASP in the year-ago quarter was higher, $68.67 compared to the latest quarter's $62.52. That would help to explain a profits drop. ®


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Water SA
On-line version ISSN 1816-7950
Print version ISSN 0378-4738
Water SA vol.35 n.2 Pretoria Jan. 2009
Destratification induced by bubble plumes as a means to reduce evaporation from open impoundments
M van Dijk*; SJ van Vuuren
Department of Civil Engineering, University of Pretoria, Pretoria 0001, South Africa
The use of thermal mixing by means of compressed air appears to have important potential for evaporation suppression on deep reservoirs. Current methods used to reduce evaporation from open-water impoundments such as floating covers, modular covers, monolayers and shade structures have many disadvantages and negative impacts on the environment. These methods impact the natural/modified aquatic ecosystem established in the dam; alter aesthetic qualities; increase the risk of dam failure in times of flood; could potentially lead to an oxygen reduction in the water; and may compromise the natural water treatment functions and operations such as the reduction of harmful bacteria, exposure to sunlight (form of disinfection) and natural and mechanical aeration thereby increasing treatment costs.
The methodology proposed in this paper to help reduce evaporation losses from open-water impoundments, which indirectly addresses problems of water shortage and the associated economic impacts, involves the destratification of the water body using a bubble plume operated with minimal energy input to reduce surface water temperatures, with, a subsequent reduction in evaporation.
The literature, although limited, indicates that this proposed method has merit and requires further research to identify specific reservoirs (size, depth, usage) that could benefit from such a destratification system. Evaporation suppression of as high as 30 % was achieved in some case studies.
Keywords: bubble plume, destratification, evaporation reduction, evaporation suppression
Due to South Africa's climate and geographical situation, South Africa experiences low rainfall and high evaporation rates leading to shortages of water and high losses of water from water storage facilities. Because of the sporadic, temporal and spatial distribution of precipitation, the only way that water supply can be controlled to meet demand is through storage. According to the National Water Resource Strategy (DWAF, 2004), South Africa depends mainly on surface water resources for most of its urban, industrial and irrigation requirements.
South African water authorities should therefore use the limited available resources effectively, efficiently and wisely for a sustainable future. The cost of evaporation losses is significant and has a major effect on the design and operation of reservoirs.
The water lost due to storage evaporation depends upon many factors including atmospheric evaporative demand, the size of the water storage and storage method (Craig, 2006). According to Craig (2006) there have been many attempts to reduce losses by altering how the water is stored, firstly by increasing the water depth and secondly by installing a good quality liner to prevent seepage. Current methods used to reduce evaporation from water resources such as floating covers, modular covers, monolayers and shade structures could have many disadvantages and negative impacts on the environment (Hughes et al., 1974). A scoping study done by Watts (2005) provides a number of commercially available products used in evaporation reduction such as shade cloth, polystyrene beads and foamed rubber. These are however mostly applicable to small dams.
These methods impact the natural/modified aquatic ecosystem established in the dam; alter aesthetic qualities; increase the risk of dam failure in times of flood; could potentially lead to an oxygen reduction in the water; and may compromise the natural water treatment functions and operations such as the reduction of harmful bacteria, exposure to sunlight (form of disinfection) and natural and mechanical aeration thereby increasing treatment costs.
The methodology proposed to reduce the effect of evaporation losses and indirectly solving the water shortage and increase the reliability of supply, involves the destratification of the water body using a bubble plume operated with minimal energy input to reduce surface water temperatures and subsequently reducing evaporation.
During summer, the surface water (epilimnion) of a reservoir heats and therefore becomes less dense. Below this surface layer, which is nominally 3 to 4 m deep, the water remains cold and more dense (hypolimnion). These layers are separated by a thermocline which acts somewhat as a barrier to normal convection circulation and prevents the hypolimnetic water from being circulated or mixed. This phenomenon is commonly termed stratification. By injecting a bubble plume in the cold hypolimnion layer artificial destratification will occur by means of diffusion, when this bubble rises to the surface through the different temperature layers.
In the summer months, water bodies stratify forming layers with different temperatures. The surface water reaches high temperatures, aiding evaporation. Artificial destratification, mixing to dissipate layers with the aim of uniform temperature gradients over the depth of the storage, is believed to reduce evaporation by bringing cold water from the lower layers to the surface, thereby reducing the surface water temperature. The air injection bubble plume system used for water quality applications has been observed to be one of the most cost effective, appropriate and viable solutions for artificial destratification. The application of this methodology for reducing open-water evaporation seems to have potential as first shown by Hughes et al. (1975) although very few references were found where this method is being used as a technique to reduce evaporation.
Objective of study
The main objective of this study was to investigate the potential reduction of evaporation from reservoirs by the destratification of the water system, thereby altering the temperature gradient. The bubbles released at a slow rate will disturb the stratified water layers as these move to the surface, bringing cooler water particles to the surface. Through a process of diffusion the cooler water will spread horizontally, as well as having a ripple effect from the source outwards. This will gradually lower the water surface temperature, increasing the energy needed for evaporation, thereby reducing evaporation from the reservoir.
The key objectives of the study were:
To investigate the potential of artificial destratification as a method for reducing the evaporation from reservoirs
To investigate the effectiveness of an air injection bubble plume system to destratify a water body (reservoir)
The quantification of the effect of the destratification on the surface water temperatures
The quantification of the reduction in evaporation loss from the reservoir.
The obtained results together with the information available from literature will be used in evaluating whether this proposed method is economically viable on a large scale and can be used in major reservoirs in South Africa.
In order to meet the set key objectives a literature study was conducted to determine how a water body could be destratified. This included mechanical mixing and buoyant bubble plume releasing. Furthermore the evaporation process was explored to determine what the influence would be if the surface layer of the open-water impoundment was to be altered. The dominant components of the evaporation process needs to be identified in order to simplify the evaporation quantification process. Experimental and field work was conducted to get acquainted with the practical facets of the proposed method.
Evaporation constitutes the physical process by which water in the liquid phase becomes atmospheric water vapour. In South Africa the evaporation losses from our reservoirs are significant. As shown in Fig. 1, the evaporation rate is greater than 1 400 mm/a for most of the country. Evaporation has a significant influence on the yield of water supply reservoirs and on the economics of building reservoirs of various sizes.
As described by Serrano (1997), the driving force in the evaporation process is solar radiation, which provides energy to the water molecules near the water body surface. The radiation causes an increase in the vibratory kinetic energy of the water molecules and when the amplitude of vibration overcomes the forces of molecular attraction, the molecules escape from the liquid mass into the air immediately above the surface. Absorption of energy is a prerequisite for the occurrence of evaporation.
The amount of energy required for the evaporation of one kilogram of water is called the latent heat of vaporisation, L (cal/kg). The required energy decreases as the temperature of the evaporating water increases or, in line with the objective of decreasing the evaporation, if the temperature of the evaporating water surface is decreased, this results in an additional energy requirement.
Evaporation is a diffusive process (transport mechanism) which is governed by Fick's law of diffusion. Water vapour will move from sections of air mass with high concentrations (just above the water surface) to sections of air with low concentrations (higher atmospheric regions of dryer air). The maximum number of molecules held by the air corresponds to the so called saturation vapour pressure which is a function of air temperature. The ratio of the actual vapour pressure to the saturated vapour pressure is defined as the relative humidity usually expressed as a percentage. High relative humidity values (>80%) indicate humid conditions with subsequent expected low evaporation rates.
The transport mechanism causes a vapour pressure gradient and thus the moist air immediately above the water surface is replaced with dryer air. This process is influenced by turbulent eddies resulting from the upward movement of moist air (seeing that moist air is lighter than dry air) as well as wind currents displacing moist air away from the surface. A general equation to express the evaporation rate that considers the above is Dalton's (1802) law in Serrano (1997).
E = evaporation rate (mm/d)
es = saturated vapour pressure at the water surface temperature (mmHg)
ea = vapour pressure at a fixed distance above the evaporating surface (mmHg)
u = horizontal wind speed (km/h)
f (u) = function of the wind speed and other factors (h.mm / d.km. mmHg)
There is a strong correlation between evaporation and water surface temperature. This is clearly shown in the monotonic function relating water temperature to saturation vapour pressure.
There are various forms of Eq. (1), collectively called mass transfer equations, such as Harbeck (1962):
A = reservoir surface area (km²)
W = wind speed at a point 2 m above the water surface (km/hour)
ea = vapour pressure at a point 2 m above the water surface (mmHg)
k = mass transfer coefficient equal to 0.054 (mm.h/ d.km0.9.mmHg)
Hughes et al. (1975) provided an evaporation suppression equation as a function of change in water surface temperature where es is a factor rather than an additive component of the equation as shown in Eqs. (1) and (2). This allowed for elimination of calculating the actual evaporation magnitudes and therefore the need to determine wind and other unchanged parameters combined into f (u). The basic evaporation suppression relationship is:
f(T) = The function relating temperature to saturation vapour pressure
Tc = Temperature of the cooled system (thermally mixed) (°C)
Tn = Temperature during normal conditions in the reservoir (°C)
Another method which is commonly used is the water balance technique (Eq. (4). The application of this method requires an account of all streams, entering and leaving the reservoir, measured precipitation and estimates of net groundwater contributions.
E = evaporation rate (m3/s)
Qi = average inflow rate (m3/s)
Qo = average outflow rate (m3/s)
ΔS = change in storage volume (m3)
Δt = period of analysis (s)
It is required to consider the heat addition and loss sources over time to enable integration of these effects on a reservoir and establish the potential suppression relationship. The energy budget technique is a valuable method for defining the heat flux. As mentioned before, evaporation requires the absorption of energy either supplied by solar radiation or the water body itself. As detailed in Serrano (1997), radiation is the emission of energy in the form of electromagnetic waves from all bodies above the absolute zero temperature, and thus it is possible to establish an energy balance (energy budget). The US Geological Survey researchers defined nine variables with units' cal/m².d, which constitute the energy budget (Harbeck, 1962 and Hughes et al., 1975) and illustrated in Fig. 2 (next page).
Qs = incoming solar radiation
Qr = reflected solar radiation
Qa = incoming solar atmospheric long-wave radiation
Qar = reflected atmospheric long-wave solar radiation
Qbs = long wave radiation emitted by the body of water
Qv = energy advected into or from the reservoir (inflow and outflow)
Qe = energy used in evaporation
Qh = energy loss as sensible heat
Qw = energy advected by evaporated water
ΔQ = change in reservoir energy
From the analysis performed by Hughes et al. (1975) 2 of the 9 parameters emerged as being dominant; these are Qe (evaporation latent heat) and Qv (the outflow component).
Artificial destratification
To destratify a reservoir a bubble plume diffuser could be used. Bubbles released via the diffuser will rise through to the surface. The bubbles entrain cold and dense water in the cold hypolimnion layer and form a plume. This plume will rise through the layers until the mixture of air-water reaches its natural buoyancy where its density is equal to the density of the surrounding water (Moshfegi et al., 2005). At this point the plume stops and the entrained water is detrained and emitted horizontally. The heavy hypolimnetic water is carried up to the epilimnion and after mixing with the light epilimnetic water, it submerges down to the neutral buoyancy level in the thermocline where it forms an intermediate layer with relatively homogeneous density (Imteaz and Asaeda, 2000). This layer expands up and down until the entire depth is occupied by this layer. The replacement rates of the epilimnion and hypolimnion depend on the plume number (Asaeda and Imberger (1993) and Lemckert and Imberger (1993)). A high plume number indicates a rapid thickening of the intermediate layer.
There are usually 3 types of plumes which may form in a linearly stratified flow. The type of plume will depend on the relative strength of the stratification as well as the air flow rate (Asaeda and Imberger (1993). The optimum value of the air flow rate is the rate which produces one ejection at the water surface (Moshfegi et al., 2005). The diffuser is also designed to have a number of clusters where the individual bubble plumes have no interaction with each other since this will lower their efficiency. The diffuser is placed at a certain height above the bottom of the reservoir to prevent the disturbance of the bed sediments and the subsequent carrying of nutrients to the surface.
Lackey (1972) describes an aerator (Helixor) which consisted of a 46 cm diameter polyethylene tube containing a continuous coil which divides the tube into separate longitudinal sections. Air is released at the Helixor bottom through several small holes. The coiled design lengthens the air-water interface compared to a simple perforated pipe. The Parvin Lake in Colorado has a surface area of 19 ha and maximum depth of 10 m. The thermal stratification could effectively be eliminated by installing 2 aerators operating at 2.1 m3/min. In this set-up it was done to improve dissolved oxygen levels and to keep part of the lake ice-free during winter.
Kothandaram and Evans (1982) utilised a mechanical axial flow pump destratifier in conjunction with an aerator to eliminate the thermal layers and add oxygen to the reservoir for improvement of the water quality only, i.e. no mention of the additional benefit of reduced evaporation. Kirke and Gezawy (1997) designed and tested a mechanical circulator/aerator for lakes and reservoirs. Their designed system successfully destratified a reservoir and although it does not add oxygen directly, through natural processes of diffusion, wind, etc., the colder water is oxygenated.
An investigation by Henderson-Sellers to determine how destratification and re-aeration can be used as tools for in-lake management to prevent the lack of oxygen and the negative impact on water quality indicated that a spin-off to destratification is that the surface temperature is reduced in summer (Henderson-Sellers, 1981). This in turn has an influence on the energy budget and will result in a decrease in the rate of evaporation. According to Henderson-Sellers a first-order approximation suggests that a 2°C drop in surface temperature during the summer months is realistic which would result in a 10% saving.
Destratification was proposed as one of the alternatives to increase the water temperature at the bottom outlet of a reservoir (Sherman, 2000) (see Fig. 3). The thermal mixing of the water would result in warmer water released into the river and in this way mitigate the effect of cold water pollution below dams. According to Sherman, Lorenzen and Fast (1977) proposed a rule of thumb of 150 ℓ/s of compressed air per 100 ha of reservoir surface area. The larger the destratification system the faster it can achieve the desired amount of destratification.
Sufficient destratification could result, depending on the month, in a reduced water surface temperature and the subsequent evaporation suppression. A suppression model for the thermal mixing was conceptualised by Hughes et al. (1975) and consisted of:
Basic concept: Idealised suppression is calculated as a function of change in water surface temperature (ergo change in vapour pressure) caused by perfect mixing (isothermal temperature profile).
Secondary effects: Sufficiently important secondary effects are included in the model such as:
- Extra heat due to the decrease in heat loss due to evaporation caused by suppression during the previous period, and
- Heat loss from the reservoir due to warmer than normal outflow from the mixed reservoir.
Time resolution: Model parameters are determined on a monthly average basis. Heat flux is accumulated between months up to 6 months for reservoirs on which a seasonal analysis is appropriate and for annual or multi-year periods where carryover storage is important.
Results of destratification studies
A study by Koberg and Ford (1965) quantified the decrease in evaporation due to destratification of Lake Wohlford in California. The lake has a volume of 3.1 Mm3, its area is 53.1 ha and it has a maximum depth of only 15 m. A 15% reduction in evaporation was observed from May to June although the evaporation was 9% higher from September to November resulting in a net saving of 6%.
A research project undertaken in 1975 by the Utah Water Research Laboratory applied the suppression model as described above to 10 reservoirs in Utah in the United States. Table 1 shows the results of the seasonal model for reservoirs which had temperature profiles.
The flow index is computed from the monthly outflow /storage ratios; alternatively a seasonal index can be computed by weighting these ratios according to monthly evaporation factors which could provide a better indicator of the impact of outflow on seasonal suppression. Hughes et al. (1975) indicated that the suppression heat is the dominant secondary effect in large reservoirs.
According to Brown (1988) there are very few other references to destratification as a means to reduce evaporation. Hoy and Stephens (1979) in Brown (1988) analysed data from the Tarago Reservoir in Victoria (37.6 Mm3, surface area of 360 ha and maximum depth of 23 m). They estimated that lake evaporation was reduced by 25% over a 3-month period but the potential increase in evaporation in the following months was not determined.
Experimental set-up
One of the objectives of this research project was the quantification of the reduction in evaporation losses. An experimental set-up where the effect of destratifying the water body in a controlled environment and the subsequent reduction in evaporation could be determined was constructed at the hydraulic laboratories of the Department of Water Affairs and Forestry (DWAF) in Pretoria-West. Two reservoirs (Reservoir A and B) were constructed as shown in Fig. 4 (next page). Reservoir A was the benchmark reservoir with the destratification taking place in Reservoir B.
The reservoirs were insulated and roof covers were secured over the reservoirs to reduce the effect of precipitation, which would have a huge effect on reducing the water level temperatures and destratifying the layers. An onsite weather station was installed to record the exact weather conditions influencing the reservoirs. The station contained a rainfall meter, temperature sensors, anemometer to measure wind speed and wind direction. The change in water levels was determined using fixed point gauges. Based on the rate of change in water levels the evaporation rate could be determined.
Thermocouple sensors were used to measure the water temperatures of the different layers in the reservoirs to ensure that a stratified body of water was obtained. Thermocouples were placed 150, 250, 350, 450 and 1 150 mm below the surface. A data logger was used to record the data from the thermocouple sensors at a rate of a data set every 3 h. Both reservoirs formed thermal layers and after the bubble plume was introduced in Reservoir B the thermal layers were eliminated.
The bubble plume used to induce destratification was created with the use of an electronically controlled air regulator that regulated the induction of air into the system. The air induction box (AIB), shown in Fig. 5, was used to inject controlled volumes of air. The AIB is simply a regulator which can be set to release a specific volume of air at certain intervals. A small experimental set-up such as this does not require a large disturbance to create the destratification. The disturbance caused by simply removing the thermocouples from the water body would result in the thermal layers mixing. The air injected into Reservoir B was not optimised and it is believed that too much was injected.
The experimental work did underline the limitations of the set-up. The thermal effects on the sides of the reservoirs as well as the influence of the roof covers cannot be ignored. The focus was on trying to establish whether there is a difference in the rates of evaporation between a stratified reservoir and a thermally mixed reservoir. Although temperatures and all the other weather-related parameters were measured the difference in evaporation is only measured by means of the point gauges. During a period from March to April when the reservoirs were both allowed to stratify the 2 reservoirs had similar evaporation rates.
The results indicated that Reservoir B could be destratified using the bubble plume, and that there is a reduction in evaporation in this reservoir compared to the evaporation experienced in Reservoir A. The evaporation rate for a 2-month period (May and June), when Reservoir B was mixed with the aerator, indicated a reduction in evaporation of approximately 1%/month when comparing Reservoir B with that of A, although this was not an ideal period for this experiment. The measured evaporation in both reservoirs was less than the average monthly evaporation rate for Pretoria West which indicates that the roof covers played a significant role in the obtained values.
Field investigation
Destratification, where the colder bottom water is circulated, has been successfully applied to reservoirs which are deep (deeper than 20 m) but according to Craig (2006) it is less appropriate for most agricultural storages which are usually less than 7 m deep.
An experiment was also conducted at the Water Quality Resource Services' grounds at Roodeplaat Dam to determine the logistics involved in providing an aerator system for destratification. A 20 mm HDPE pipe 200 m in length was laid under the water into the dam. A diffuser was placed at the one end at a depth of approximately 16 m, activated by means of a solenoid valve. At the other end an air compressor with a timer control was connected. The compressor at 100 m pressure could discharge a specific volume bubble plume by opening the solenoid valve for a set period of time. A temperature probe and data logger were placed at the water surface within a 1 m radius above the diffuser to measure the change in temperature.
Various configurations were utilised, to alter the bubble plume volume and shape as well as the release times and intervals. The aim was to obtain an optimum set-up that would have the greatest effect on the water surface temperatures. In Fig. 6 the bubble plume reaching the surface can be seen.
As indicated in Fig. 7 a bubble plume was released every 10 min with logging taking place at 2 min intervals. The surface water temperature clearly drops by approximately 1 to 2.5ºC every time a bubble plume is released. The water surface temperature, however, returns to its original temperature again due to the mixing with the surrounding water. If a number of these release points were placed throughout the dam it is envisaged that the surface temperature could be reduced in this way.
By comparing the energy used by the bubble plume system, to that needed to reheat the water body a cost-benefit ratio can be determined and the economic viability of the proposed system determined.
There are some models available that could assist in designing the destratification system at a large scale. This is required to determine the number and position of release points, the volume and rate at which air should be released at each point and the anticipated mixed isothermal temperature of the body of water.
Models to determine the installation specifications and destratification evolution
There are various ways in which the full-scale artificial destratification system can be designed. The following 3 models/tools could be used to determine the optimum destratification system.
Destrat software
This software is used to calculate the specifications of the bubble plume. The model calculates the power requirements, the optimum flow, diffuser length and the number of clusters required (Moshfegi et al., 2005). The highest possible mixing efficiency will minimise the operating cost of the diffuser system. The model calculates the required air flow rate per diffuser port as well as the power required by each plume, the number of clusters, diffuser length as well as the pressure drop and head loss to determine the power required by each system.
Dynamic Reservoir Simulation Model (DYRESM)
DYRESM is a one-dimensional hydrodynamic model for predicting the vertical distribution of temperature, salinity and density in reservoirs satisfying the one-dimensional approximation. The one-dimensional approximation is valid when the forces that act in on a water body to destabilise it such as wind stress, surface cooling or rapid inflows do not act over prolonged periods of time.
The model provides quantifiably verifiable predictions of the thermal characteristics in such reservoir systems. The model parameterises the important physical processes leading to temporal changes in the temperature, salinity and density distributions in reservoirs.
The model divides a reservoir into a series of horizontal layers of variable size which can expand, contract, amalgamate, divide and move up and down according to the physical processes represented in the reservoir.
In DYRESM a simple single core plume is modelled with the movement of the plume determined from 3 differential equations of conservation of mass, momentum and buoyancy (Patterson and Imberger, 1989). The model can also be calibrated against field data using for instance thermistor chains and changing the major parameters.
Computational fluid dynamics (CFD)
Power efficiency in aeration devices for deep water bodies is essential due to the high injection pressure needed. Design optimisation with sound scientific tools is thus essential, and numerical modelling is without doubt one of the key tools in engineering. Buscaglia, Bombardelli and Garcia have developed a numerical model for large-scale bubble plumes accounting for mass transfer effects (Buscaglia et al., 2002).
Economic feasibility
There are a number of ways in which evaporation can be reduced as mentioned earlier. Watts (2005) developed a spreadsheet-based economic viability calculator to allow farmers to determine the circumstances under which an evaporation reduction system would be economical. The model includes:
Details of the dam (capacity, depth, surface area)
Local climatic data (rainfall, evaporation)
Estimates of operating conditions
Capital, operating and maintenance costs for the evaporation reduction system
Estimated life of the components of the system
Estimate of the evaporation reduction efficiency of the selected system
Current value of alternative water
Appropriate interest rates
Current gross margin for the crop grown.
In a study by Kothandaram et al. (1979) for the Illinois Institute of Natural Resources a pilot lake restoration investigation utilising aeration and destratification in Lake Catherine in the United States was undertaken. The pilot study was in operation over the period 18 May to 4 October 1978 and during this time the aerator utilised 45 800 kWh. Lake Catherine has a volume of 3.03 Mm3, surface area of 0.59 km² and a mean depth of 5.1 m. The cost of operating a successful destratification system like the one in Lake Catherine, would be ±R2 000/month (based on a 20c/kWh unit cost for electricity, low-demand season and only taking the active energy charge into account). The energy requirement to destratify 1 Mℓ (1 000 m3) of water is 4.52 W.
Although the authors of the study at Lake Catherine did not determine the reduction in evaporation, assuming a conservatively low 2% reduction could save ±1 750 m3/month. A reduction of 5% and higher might make it feasible to invest in a destratification system.
Hughes et al. (1975) utilised cost functions developed by Symons (1971) to analyse the reservoirs in the State of Utah. Symons (1971) summarises the results of a survey of water suppliers who have used artificial destratification for water quality reasons. Symons (1971) developed 3 figures showing the energy capacity requirements, the capital investment costs and the operating and maintenance costs each as a function of reservoir volume. These same cost functions were used by Hughes et al. (1975) to determine the water salvage costs as shown in Table 2.
It is clear from Table 2 that the larger reservoirs have the greatest potential of being feasible.
An example for South Africa: There could be huge potential savings if the Sterkfontein Dam which is situated in the very upper reaches of the Vaal Dam catchment on the Nuwejaarspruit could be equipped with a destratification system.. The Sterkfontein Dam has a very small catchment area with negligible natural inflow receiving most of its water via the Tugela-Vaal Project. This is a pumped-storage scheme involving the net transfer of up to 630 x 106 m3 of water from KwaZulu-Natal. The water from KwaZulu-Natal is stored in Sterkfontein Dam and released to Vaal Dam via the Wilge River. Due to the favourable storage and climatic characteristics of Sterkfontein Dam, it is beneficial to store water in the deep cool Sterkfontein Dam and only release water to the shallow Vaal Dam when needed. The evaporation losses from Sterkfontein Dam, which is a highly efficient storage unit with an annual evaporation of 1 300 mm, are approximately 35 x 106 m3/a, which represents approximately 10% of the losses that would be experienced from Vaal Dam for a similar volume. Even a small 1% reduction in evaporation in Sterkfontein Dam could save up to 350 000 m3/a of expensive pumped water.
The total monetary cost of evaporation loss is significant and restricts development in South Africa. This research is still in its early stages but it is hoped that the method could be further developed and implemented on a pilot scheme in South Africa to demonstrate the benefits. The use of thermal mixing by compressed air appears to have important potential for evaporation suppression in deep reservoirs. The necessary conditions to achieve significant evaporation suppression according to Hughes et al. (1975) are as follows:
The reservoir should have sufficient depth (greater than ±18 m) to produce a marked natural thermocline and provide a relatively large volume of cold water for mixing.
An outlet/abstraction that is below the thermocline with sufficient outflow in relation to storage to transport a significant amount of excess heat from the reservoir.
The proposed system could have additional benefits such as:
Improving the overall water quality;
Reducing operating budget for raw water treatment;
Increasing the dissolved oxygen (DO) levels throughout the reservoir;
Increasing the fish habitat;
Reduction in algal growth by mixing of algae deeper into the water column and starving them of light, therefore reducing the sediment phosphorus load available to the water column and so starving the algae of nutrients (Auer et al., 1993). In other words phosphorus management through hypolimnetic aeration; and
Potentially improved habitat downstream of the reservoir (DO levels and temperature).
However, on the negative side, according to Henderson-Sellers (1981) there are some water users who require the abstracted water for potable use to be below a specified maximum and some fish species habitats in the thermocline layer could be destroyed when the lake is destratified.
During the field investigation it became clear that a number of bubble plume release points would be required to have an effect on the entire surface area. The design of the artificial destratification system still needs some further investigation and the models/tools described earlier would certainly assist in this regard.
Because of the major potential for water conservation in general as well as water for energy production additional research on destratification of deep reservoirs should be undertaken.
The experimental tests could be conducted on a larger scale to determine the extent and area of influence of the destratification system.
The suppression model as proposed by Hughes et al (1975) could be implemented on a number of South Africa's deep reservoirs and the potential suppression determined.
Experimental tests should be conducted in the summer months when evaporation rates are at a peak and over a few seasons to incorporate resulting weather and water temperature fluctuations and turnovers. Results from similar seasons could be compared to evaluate the accuracy and interpretation of results.
An alternative energy source for the air injection system could be investigated. Wind or solar energy would be ideal for application of the evaporation reduction system on dams where electrical energy would be difficult to supply and maintain.
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This paper was originally presented at the 2008 Water Institute of Southern Africa (WISA) Biennial Conference, Sun City, South Africa, 18-22 May 2008.
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