シャドーイング練習: Introduction 1, Context - 動画で英語スピーキングを学ぶ
レッスンを作成中...
1
Cement Chemistry for Sustainable Cementia Materials Hello and welcome to this series on Cement Chemistry for Sustainable Cementia Materials.
2
In this series of modules, we're going to look at the cement chemistry and how this helps us to understand the sustainability of these very important materials.
3
Most of the modules should be really understandable to anybody with a fairly basic knowledge of high school chemistry.
4
So in this first module, we're going to look at the overall context.
5
We're going to look at the role of cementitious material in the world today
6
and what are the origins of their CO2 footprint.
7
Now, in this first slide, we can see the overwhelming dominance of cementitious materials.
8
They make up between 30 to 50 percent of everything we produce,
9
probably about 50 percent of solid materials and 30 percent if we include things like fossil fuels.
10
And in the light of that, the fact that they're responsible for CO2 emissions of around 5 to 10 percent is a very good ratio.
11
But more importantly, we can really see
12
that it would in no way be possible to replace semantitious materials with alternatives at any meaningful level.
13
For example, if we look at the amount of wood produced worldwide, this is between 10 and 15% the amount of cementitious materials.
14
And already it's estimated that this amount of wood is beyond the limits of sustainability.
15
That's to say we're cutting down more trees than we're planting.
16
So while this may be a nice option in Europe and North America, it's really not practical for the many people who need to be housed in countries like China,
17
India, Africa, South America.
18
This slide here really shows how the environmental footprint of concrete is very low.
19
And we should talk about concrete because concrete is the final material we really use.
20
Cement is the precursor and there's roughly about 10% of cement in concrete.
21
On the right here, I've normalized these figures compared to the highest, which is aluminium.
22
You can see very vividly just how much energy and CO2 you can save by recycling aluminium.
23
And I hope after seeing this, you don't throw your Coke can in the bin anymore.
24
But concrete is really extremely low, lower than almost all other materials.
25
Of course, this is just on a weight basis.
26
When you put this into a structure, it becomes more complicated.
27
We're not going to go into that here, but generally, even in that situation,
28
concrete still comes out very strongly as an environmentally friendly material.
29
The amount of cement we're using has increased very, very dramatically in the past few decades.
30
Since 1950, the population has increased about threefold, and in the same period,
31
the amount of cement we use has increased by about 34 times.
32
In recent decades, this has really been driven by the development in China.
33
And we should not view this negatively because this development has lifted a lot of people out of poverty.
34
It's provided them with decent homes, with roads, railways to get around and everything like that.
35
But we certainly cannot imagine that this growth in demand for cement is going to slow down because there are many,
36
many other parts of the world where people still haven't had decent housing or transportation systems.
37
Finally, what we do with our lives and the CO2 produced is a question of choices.
38
And here again, you know, if we decide to build a house, we make maybe a house for a family of three people,
39
this will typically take about 10 to 20 tons of cement and last for about 50 years.
40
So we can calculate from that
41
that the CO2 to do with your materials in your house is about 12 kilograms a month.
42
Now, if you're driving a car, which you almost certainly are,
43
that same family of three will probably drive at least 10,000 kilometers a year.
44
And then they'll be consuming fossil fuels, which will be producing about 90 kilograms of CO2 per year,
45
seven or eight times more than the materials in their house.
46
But we should also reflect on our other choices in life, for example, the food we eat.
47
Here you can see for a very meat intensive diet,
48
the associated CO2 production would be around five to seven kilograms of CO2 per day.
49
whereas a vegetarian diet is much lower at around 3 to 4 kilograms of CO2 per day.
50
And so if we calculate for the same imaginary family of three that they went from eating meat to being vegetarian
51
maybe for just two
52
or three days a month this would be equivalent to saving all the CO2 that they needed to build their house.
53
So rather than just blaming the producers of these materials we have to think about what we're doing in our lives
54
and what we choose to do that produces CO2.
55
Okay, there's no reason for complacency because if we did nothing about the CO2 footprint of cementitious materials,
56
we could end up in a situation like this.
57
Here we see the blue line is the trajectory
58
that has been estimated we should try to meet if we're to restrict global warming to this two degrees temperature rise.
59
Whether we're going to do that or not is another question, but that's the trajectory of overall global emissions if we're going to do that.
60
If we achieve that blue line and we did nothing about cement,
61
then the emissions from the production of cement and cementitious materials would follow the red line.
62
And we see
63
that by 2050 we would end up in a situation where
64
cementitious materials would be responsible for something like 30% of world CO2 emissions, which is clearly unacceptable.
65
So where is the consumption of cement taking place?
66
What we see here is the distribution of cement use around the world.
67
And only about 10% of cement use is taking place in OECD countries.
68
And in these countries, it's forecast that demand will really stay pretty much constant.
69
More than 90% of consumption is taking part in the developing world,
70
particularly in China, which has been very dominant over the past two decades.
71
It's been estimated in the last three years, China produced more concrete than was produced in the whole of North America in the 20th century.
72
and many other countries like India in particular are looking to follow this development path to provide decent houses for their people,
73
decent rail systems, decent road systems and this will inevitably mean that the growth in use of cement is going to increase.
74
So if we're going to meet this challenge of the growing demand for cement we need solutions
75
which are first of all practical, They can be used by unskilled workers.
76
And, you know, this shows you the kind of typical situation you can have for mixing concrete.
77
The example is from India.
78
And also economically.
79
Now, you know, cement is an incredibly cheap material.
80
In most of Europe, you can buy a ton of cement for less than 100 euros for a whole ton.
81
In many developing countries, though, the prices are actually higher, even though the incomes are lower.
82
So it's very important that we have solutions
83
which are really economically viable for these countries where there's this huge need for building infrastructure and housing,
84
etc. So let's look at where these CO2 emissions are coming from.
85
Unlike most other industrial processes, only a minority of the CO2 emissions are coming from the energy consumption.
86
Producing cement is a high temperature process.
87
you're going up to temperatures of 1450 or so and this does take energy but it's still the minor amount.
88
A cement kiln as we see here looks like a fairly unsophisticated type of instrument.
89
But this is in fact not true
90
because in the past few decades there's been very dramatic improvement in the amount of energy needed to produce cement.
91
And in really state-of-the-art equipment now the production process is highly optimized up to nearly 80% of the thermodynamic limit
92
which is those of you who or study thermodynamics will know, is very close to the maximum you can achieve.
93
Another factor which is important is that rather than using fossil fuels, which used to be the dominant means in the past,
94
nowadays we can use a wide variety of waste fuels.
95
So for example, off cuts from producing furniture,
96
old car tires, Many, many different kind of waste can be burnt in a cement kiln.
97
And in many parts of Europe, plants are using more than 80% of waste fuels.
98
So this is a very efficient tool for valorizing waste materials.
99
So if we're going to make improvements, we need to turn to the other side, to the 60% of the equation.
100
And this 60%, this comes from the breakdown of calcium carbonate into calcium oxide and CO2.
101
Calcium carbonate, this is in fact limestone, which is 80% of the raw material used to make cement.
102
Now, the fact we have this chemical CO2 means that if we're going to reduce this, then we're going to have,
103
this has implications for the chemistry of the cement.
104
And that means it has implications for the whole way it behaves, in use, etc., etc., which of course is a big challenge.
105
So what have we seen in this lecture?
106
Well, we've seen how important semantitious materials are, how they make up by far the overwhelming majority of all the materials we used
107
and therefore cannot be replaced by other materials.
108
We've seen that in fact the environmental footprint from these materials is in fact quite low
109
and we've looked at where the CO2 emissions come from
110
and we've seen that most of the CO2 emissions come from the chemical breakdown of limestone,
111
that's calcium carbonate, and therefore we can't really imagine to do much about CO2 emissions by, for example, looking at alternative energies.
112
So in the next lecture, we're going to go into more detail about why the chemistry of cement is as it is.
113
So I look forward to seeing you next time and I hope you've enjoyed this first module.
114
If you want to find out more, then this publication, Ecoefficient Cements, which we published in November 2016,
115
gives you a very good background to all the aspects I will tackle in this first module.
📺 同じチャンネル
✨ おすすめ動画
C11
56 文
MinuteCement - LC3
Business EnglishUniversity StudentsWorking Adults
C12
91 文
Course Introduction | AZ-104 | Episode 1
Cambridge Exam PrepBusiness EnglishUniversity Students
C1132 文
Petroleum - 06 - Drilling Fluid Laboratory
Business EnglishUniversity StudentsWorking Adults
C12
174 文
Introduction to Housing - City Beautiful Basics
Business EnglishUniversity StudentsWorking Adults
C11
99 文
FIDIC Yellow Book 2017 Explained #construction #civilengineering #quantitysurveyor
Business EnglishUniversity StudentsWorking Adults
C124 文
Sofeast PCB Video Series Introduction
Business EnglishUniversity StudentsWorking Adults
C12
65 文
1 Week - Monday: The importance of recycling
Business EnglishUniversity StudentsWorking Adults
C12
102 文
Chemical Manufacturing 101 - Texas
Business EnglishUniversity StudentsWorking Adults
C12
32 文
Day 1.2
Business EnglishUniversity StudentsWorking Adults
B22
113 文
How Life Will Look Like In 2050
Business EnglishUniversity StudentsWorking Adults
C177 文
Unit 1.1: Introduction to Business Management - IB Business Management
Cambridge Exam PrepBusiness EnglishUniversity Students
このレッスンの語彙とスピーキングのポイント
このC1レベルのスピーキングレッスンは、動画「Introduction 1, Context」を教材にしています。 繰り返し出てくる語は次のとおりです：cement, material, emissions, concrete, amount。 この動画には、シャドーイング用の文が115文、単語が1706語あります。 音声の長さは11:57です。 話す速さは1分あたり約143語で安定しており、シャドーイングしやすいペースです。 単語の86%は英語の頻出3,000語に含まれます。残りは練習の前に確認しておきましょう。
この動画の重要語彙
動画の中で特に難しい単語15語を、発音と意味つきで紹介します。
| 単語 | 発音 | 意味 |
|---|---|---|
| cement 名詞 | /səˈmɛnt/ | セメント |
| module 名詞 | /ˈmɑd͡ʒul/ | モジュール |
| kilogram 名詞 | /ˈkɪləɡɹæm/ | キログラム, キロ |
| footprint 名詞 | /ˈfʊtpɹɪnt/ | 足跡 |
| calcium 名詞 | /ˈkælsi.əm/ | カルシウム, 石灰素 |
| carbonate 名詞 | /ˈkɑɹbəneɪt/ | 炭酸塩 |
| fossil 名詞 | /ˈfɑsl̩/ | 化石 |
| kiln 名詞 | /kɪln/ | 窯, 炉 |
| overwhelm 動詞 | /ˌoʊ.vɚˈwɛlm/ | 圧倒する |
| trajectory 名詞 | /tɹəˈd͡ʒɛktəɹi/ | 軌道, 弾道 |
| aluminium 名詞 | /ˌæl.(j)uˈmɪn.i.əm/ | アルミニウム, 軽銀 |
| limestone 名詞 | /ˈlaɪmˌstoʊn/ | 石灰岩 |
| sustainability 名詞 | /səˌsteɪnəˈbɪlɪti/ | 持続可能性, サステイナビリティ |
| vegetarian 名詞 | /vɛ.d͡ʒɪˈtɛ.ɹi.ən/ | 菜食主義者, ベジタリアン |
| calculate 動詞 | /ˈkælkjʊleɪt/ | 計算する |
動画に出てくる句動詞
| 単語 | 発音 | 意味 |
|---|---|---|
| come out 動詞 | /ˌkʌm ˈaʊt/ | 出る |
| find out 動詞 | 見出す, 調べる | |
| look forward to 動詞 | 楽しみにする | |
| slow down 動詞 | 遅らせる |
この動画の文法
話し手がよく使っている文型を、動画の実際の表現とともに紹介します。
| 文型 | 動画での表現 |
|---|---|
| 「used to」 used to + 動詞 — 今はもう違う過去の習慣や状態 | used to be · used to make |
| 現在完了形 have/has + 過去分詞 — 過去の出来事が今も関係している | I've normalized · has increased · has really been driven |
| 関係詞節 who / which + 節 — 人や物について情報を加える | people who need · highest, which is · fuels, which will |
| 受動態 be + 過去分詞 — 誰がするかより、何が起きるかに焦点を当てる | be housed · been driven · has been estimated |
注意したい発音
話し手はwe're, we've, you'reなど、短縮形や弱形を29回使っています。聞こえたとおりの短い形で発音しましょう。
- 「th」の音: thermodynamic /ˌθɝmoʊdaɪˈnæmɪk/, thermodynamics /ˌθɜː(ɹ)moʊdaɪˈnæmɪks/
- 「sh」と「zh」の音: emission /ɪˈmɪʃ.ən/, cementitious /ˌsɛmɛnˈtɪʃəs/, implication /ˌɪmpləˈkeɪʃən/, equation /ɪˈkweɪ.ʒən/
- 長い単語（アクセントの位置に注意）: cementitious /ˌsɛmɛnˈtɪʃəs/, implication /ˌɪmpləˈkeɪʃən/, trajectory /tɹəˈd͡ʒɛktəɹi/, aluminium /ˌæl.(j)uˈmɪn.i.əm/, sustainability /səˌsteɪnəˈbɪlɪti/
日本語話者が苦手な音：
- /r/ と /l/ の区別 — /l/ は舌先を歯茎につけ、/r/ はどこにもつけない: kilogram /ˈkɪləɡɹæm/, recycle /ɹəˈsaɪkəl/, valorize /ˈvæləˌraɪz/, importantly /ɪmˈpɔɹ.tənt.li/
- /v/ — /b/ にならないように、上の歯を下唇に当てる: overwhelm /ˌoʊ.vɚˈwɛlm/, vegetarian /vɛ.d͡ʒɪˈtɛ.ɹi.ən/, valorize /ˈvæləˌraɪz/, vividly /ˈvɪvɪdli/, inevitably /ɪˈnɛvɪtəbli/
- /f/ — 「フ」ではなく、上の歯と下唇で出す: footprint /ˈfʊtpɹɪnt/, fossil /ˈfɑsl̩/, forecast /ˈfɔːkɑːst/
この動画での練習方法
- まず声を出さずに動画を最後まで聞き、知らない単語をメモします。
- 通常の速度で一文ずつシャドーイングし、話し手のリズムに合うまで繰り返します。
- 自分の声を録音して元の音声と比べます。cement, module, kilogramなどの単語に特に注意しましょう。
シャドーイングとは？英語上達に効果的な理由
シャドーイング（Shadowing）は、もともとプロの通訳者養成プログラムで開発された言語学習法で、多言語習得者として知られるDr. Alexander Arguelles によって広く普及されました。方法はシンプルですが非常に効果的：ネイティブスピーカーの英語を聞きながら、1〜2秒の遅延で声に出してすぐに繰り返す——まるで「影（shadow）」のように話者を追いかけます。文法ドリルや受動的なリスニングと異なり、シャドーイングは脳と口の筋肉が同時にリアルタイムで英語を処理・再現することを強制します。研究により、発音精度、抑揚、リズム、連音、リスニング力、そして会話の流暢さが大幅に向上することが確認されています。IELTSスピーキング対策や自然な英語コミュニケーションを目指す方に特におすすめです。