Month: April 2017

Angular contact ball bearing friction torque calculation model

Angular contact ball bearing friction torque refers to all kinds of friction factors on the angular contact ball bearing of rotary torque, angular contact ball bearing.

Friction torque is a very complicated problem, it not only with bearing.

The structure of the body size, geometric accuracy, material performance, also with the work load and assembly precision, lubrication condition and processing technology and other factors the relevant.

According to the internal friction of angular contact ball bearing, angular joint ball bearing friction torque are the main factors of rolling material elastic hysteresis after, viscosity of lubricant between roller and raceway.

Rolling body and race between differential sliding, rolling on the rolling path of spin slide,friction between roller and cage and cage guide guard mount.

Brush, the six factors of the sum of friction torque is the Angle of contact the ball bearing friction torque.

The above factors caused by angular contact ball bearings formula of friction torque component we’ll explain in detail next time.

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Angular contact ball bearing friction torque characteristics

But on the described the theory of angular contact ball bearing friction torque calculation formula is in hypothesis between roller and raceway for pure roll under the premise of established, and there is no consideration of the rheological properties of lubricating oil, not adapt to high speed.

Under the mode of angular contact ball bearing friction torque calculation.High-speed shape under the state of theoretical calculation formula of angular contact ball bearing friction torque current.

Not yet, causing friction torque requirement of high speed angular contact ball bearing structure parameter design, lack of corresponding theoretical basis, only through.

The designer’s experience and improve the level of the corresponding manufacturing process and test selected for development, has certain blindness, making new products.

Bearing of greatly increased development costs.Therefore, it is necessary to research suitable for high speed conditions under the condition of angular contact ball bearing friction torque characteristics.

This paper based on the angular contact ball bearing dynamics analysis, Leon with the energy conservation principle, the establishment of angular contact ball bearing friction torque.

Theory calculation formula, analysis of working condition of bearing parameters and structure parameters on the bearing the influence of friction torque and test.

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guangzhou worlda Two Effective Methods to level up your teaching [ESL]

Written by Matt @Worlda

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Want to make your ESL teaching even more effective than they are today? Last week, we have shared Integrated Teaching for ESL Teachers and in this post, we are going to introduce you two very effective ways on how to make your class organized and how to keep your students motivated.

  •  Point System and Grouping

Adaptability: for students from primary school to high school, adapted accordingly.

Scenario 1: Class of 20 in a spacious classroom

Point system is always related with grouping, to ensure the competiveness among students. Students can be grouped into three or four, according to the size of the actual class. In any activity during the class, they are rewarded with points of a consistent system. First of all, if a group finishes a teaching-related task, they will be rewarded with 1 or 2 points, dependent on whether they answer with hint or independently. Next, for any follow-up game or activity, groups are given points in the Activity row. Lastly, for any misbehavior, minus point will be given in the behavior sector rather than directly deducted from the previous two sectors. An illustrative table is as below:

Sections Group A Group B Group C Group D
English        
Activity (Game)        
Behavior        
Total        

Note: method acquired from a Scottish teacher, Derek.

Of course, last but not least, always sum up the points and declare winners of today. No students want their 40 minutes’ efforts to end up in vain.

Note 1: Rounded-Based Point System

In practical application of this table, at times, point scale can be frustrating. Do I give 1, 2, 3, 4 points, or 5, 10, 15, 20 points. With the rounded-based point system you can literally give one group like a million or a trillion point and still make it balanced. For example,

Sections Group A Group B Group C Group D
Activity (Game) 1 million 2 billion 10 1000
3 4 1 4
20 8 2 5
4 3 1 2

the grey number in the table above is the raw point, and the blue one is the rounded one. In the sense, all points are rounded into the same scale so that no group will take obvious advantages over the other ones in one round of activity (Winner takes something but not all). This makes the temporarily losing team as competitive as the temporarily winning one. Consequently, both confidence and motivation of the students remains at an adequate level.

Scenario 2: Class of 40 with rigid seating plan

Five students around in a group will be ideal, but in real-class scenario, you could end up having like 40 students or so with a fixed, immobilized seating plan in a crowded classroom. Table below is an illustration of a good example of the point-grouping system to address the situation.

Team A (10 Ss) Team B (10 Ss) Team C (10 Ss) Team D (10 Ss)
A1: (5 Ss) B1: (5 Ss) C1: (5 Ss) D1: (5 Ss)
A2: (5 Ss) B2: (5 Ss) C2: (5 Ss) D2: (5 Ss)

Note: Ss stands for students.

40 students sitting in four columns, with 10 in each line. Vertically, the class is divided into four teams according to the seating plan in the classroom. Horizontally, the class is separated into two sections, so that we have 8 small groups now. It gives us great flexibility to organize the class and give points to each little group and four teams. For instance, if a teaching task requires competition among team with the goal of training language fluency and accuracy, four teams can compete with each other and be rewarded as teams. In another case, if the task requires discussion amongst small groups, 8 small groups can work independently. At the end of the class, instead of having one group winner, we can have winners of two levels, team winner and group winner.

Note 2: Group Name Autonomy

For new classes, or classes with students of poor language proficiency, certain level of “autocracy” of giving the groups names may come handy. But for students with adequate language proficiency, they can have their own group names. Winners can have the right to change other groups’ names with non-vulgar terms as rewards. Besides, naming groups is not the only thing you can explore with to boost the incentive of the students. Be creative and anything can be utilized to keep your students motivated.

  • Board Games

Adaptability: for students from 3rd grade to 12th grade.

Non-Target-Related games:

Games can be fun and necessary for all age group. As said by Fred Rogers, “Play is often talked about as if it were a relief from serious learning. But for children, play is serious learning. Play is really the work of childhood.”, I don’t think I have to emphasize too much on its importance, but I will explain what is non-target-related games. Meaning, the game is not designed to directly related to the teaching contents, but as a rewarding incentive to motivate students to be involving and attentive in the class. More specifically, students are given the opportunity to play the game when they echo to the teaching sessions. Points are given for consistency with the point-grouping mechanism above. Also it gives confidence to those students who have poor academic performance in linguistic classes. They can still contribute to their group and make a difference.

NTR Game 1: Air Battle

Almost everybody hears about battleship, but none have heard about Air Battle. It’s similar but with more fun. It also incorporates mathematics knowledge like practice of coordinate system. In a 10*10-grids, each team needs to draw three fighters without overlapping to each other. And they take turns to call a coordinate to shoot down others’ fighters. First group to eliminate all fighters of other groups wins. Only head shot indicates a fighter gets destroyed, or otherwise only injured.

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For more details of the game, to be continued in a separate post.

NTR Game 2: Get Rich or Die Trying

It a perfect game to regroup members from different teams to balance their competitiveness, not necessarily to even off their strength. Besides, it helps students to build leadership, or encourages more alpha players per se. Obviously, leader or alpha member comes naturally in a group, and if the leader steps down, a second one will step up to be the next leader, voluntarily or involuntarily.

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How the game is played: group students as explained above, let them take turns to draw a card from 13 cards, Ace to King, and make choices accordingly. For example, A stands for 5 points, 2 for Kidnap 1 player from other groups, 3 for Kidnap 2 players from other groups, 4 for Ground 1 player from other groups, 5 for Ground 2 players from other groups, 6 for Rescue 1 player from being grounded, 7 for Rescue 2 player from being grounded, 8 for Ground 1 player from their own group, 9 for Ground 2 players from their own group, and etc. Practically, alpha player will be grounded at the very beginning and beta player will step up to be the next alpha.

For more details of the game, to be continued in a separate post.

NTR Game 3: Typhoon

It’s a game by chance linked to the point-grouping system. It can be used in any stage or step of teaching, for quick check of students’ understanding, or for progressive reward for finishing an activity. Basically, in a 3*3 grids, candidate needs to pick a square to receive bonus or be punished. The rule is very flexible for teachers to adapt and secretive at the beginning.

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Bomb (left top): damage half of the points by a group

100/200/500: reward 100/200/500 points for a group

Typhoon (left middle):wipe out all the points of a group

Dice:chance to toss a die and get points accordingly, 1 for 100, 2 for 200 and etc.

Swap (right middle):swap points with whichever other group

Steal (right bottom):steal half of the points from whichever other group

Cards:pick a number and get points accordingly, A for 100, 2 for 200 and etc.

Remark: for point inflation and balance issue, refer to the Rounded-Based Point System in Note 1 above.

For more details of the game, to be continued in a separate post.

Target-related games:

Target-related games are different from their counterparts, in the way that their adaptability is relatively limited and closely related to teaching contents and targets. Although they are not like all-around as NTR games and usually need hours for preparation, they are more effective, relevant and well-targeted. To put it in another way, for NTR games, students do the task first and get rewards as playing, whereas for TR games the task is part of the game.

TR Game 1: Jeopardy (perfect for review)

Adapted from the famous TV show “Jeopardy”, suitable for big class and different contents, Jeopardy is perfect for review class or demo class for public. You can simply search Jeopardy game free template to get the idea or watch the show to know it quicker. It is basically that candidate makes selection and answer questions accordingly. Obviously, different questions deserve higher points.

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However, in real-class scenario, you better hide the number or randomize the number, or otherwise students could end up all picking the most difficult ones and get stumbled.

For more details of the game, to be continued in a separate post.

TR Game 2: Flip ‘n Find (learning new vocab visually)

Very simple card game as below

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You can make cards of around 8 pairs and duplicate several copies for a class. Students in a group of 4 or 5 can have one copy and take turns to flip and find match cards.

For more details of the game, to be continued in a separate post.

TR Game 3: Find friends (for engaging and involving purpose, mingling)

Each student is given a table like below:

Name Food Animal Color
Me
Friend A
Friend B

And they are all given five minutes to find as many friends sharing same favorites as they can, in order to win. Not easy to find a friend matching all three categories, so they have to keep asking questions and practice at the same time.

For more details of the game, to be continued in a separate post. 

For more games, to be compiled in another time.

NTR Game 4: Shield & Guns

NTR Game 5: Auction

NTR Game 6: Stock Market Prototype

TR Game 4:

TR Game 5:

TR Game 6:

Combo Game 1: Triathlon

Feel free to tell us what you think about the games and activities.

Thank you for your reading

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