June 29, 2005
The Isle Of Cats
Suppose there is, somewhere, a little island where a colony of a few hundred or so cats does dwell. How the cats arrived there in the first place, and how they get food is immaterial.And we're only talking about the cats of the island (the elemts of a set that is in turn a subset of the "All cats in the world" set), no other cats.
About these cats, I can state "All cats on the island are black".
This is a strong statement; it says something precise about all the cats of the island. It is also quite easy to disprove: you just have to find one single cat of any colour except black.
So, I may go for a weaker statement: "The vast majority of cats are black".
This is harder to disprove: first, you and I have to agree on a common definition of "vast majority": it can be 2/3, 3/4 etc. Second, you have to count the cats, or do a statistical study in order to back up your assertion (that would be, black cats do not constitute a vast majority).
I may do a statistical study and say: "At 95% confidence, (90 ± 7)% of cats are black".
You do your study too, and conclude that at 95% confidence only (80 ± 5)% of the cats are black. The confidence intervals overlap (even so slightly), so it's quite hard to say which statistics is right. Not to mention that we could accuse each other of having used a flawed method or an unrepresentative sample of the population.
I may also say "There are no white cats on the island".
This is another strong statement, but it's also negative, and this makes things much more complicated. For example, the only white cat may be hiding while you scout the island back and forth searching for it. So a doubt will always remain: you did not see any white cat because there is none, or because you were unable to spot the few present?
Generally, a strong negative statement is rather dishonest intellectually, because of this unresoluble doubt. Not always, sometimes a negative statement is OK; it depends from the context. For example, "There are no electrons with positive charge" is a honest statement, because those particles with positive charge and mass equal to the electron's mass are called positrons.
And all the above supposing that we both are being honest - or at least honest enough.
We may both play dirty, and things will get much more complicated.
For example, when you produce one grey cat I may insinuate that you did not find it on the island, but brought it from the mainland.
I can refuse to agree on a common definition of "vast majority" and thus make discussions about it meaningless.
I may manipulate my statistics, and/or accuse you to do so - this is different from the case discussed above, because the idea of manipulation implies a malicious will; not good-faith mistakes.
Or, when trying to prove the existence of at least one white cat you may publish a dark, out-of-focus, low- resolution photograpy showing a white indistinct blur, and insist that it's the infamous white cat. But it is impossible to tell exactly what the white blur is - accepting that the picture was indeed taken on the island. But when asked to produce better evidence, you say that it's not possible, the white cat won't show itself again but anyway you believe it exists and I should trust you. But my mate Chris says that he lost his white rabbit on the island, just a few hours before the photo was taken...
Pressed further, you then state that the white cat was kidnapped by the Evil Secret Service after you took the picture, because the son of Big Oil Corporation's CEO likes to have his summer holiday on the island, but he loathes white cats and so the CEO used his political connections to have the few remaining white cats kidnapped and killed by the ESS. And save the white cats from the capitalist oppression, too. (It does not make sense, but it isn't very different from popular conspiracy theories).
This is just a fanciful and at times intentionally silly example, but it is based on the rules of logic and, peripherally, set theory. And if you look closely, you may find that it bears some relation with real events. Saying that "There were no WMDs in Iraq!" is isomorphic with saying "There are no white cats on the island".
Comments (0)
About these cats, I can state "All cats on the island are black".
This is a strong statement; it says something precise about all the cats of the island. It is also quite easy to disprove: you just have to find one single cat of any colour except black.
So, I may go for a weaker statement: "The vast majority of cats are black".
This is harder to disprove: first, you and I have to agree on a common definition of "vast majority": it can be 2/3, 3/4 etc. Second, you have to count the cats, or do a statistical study in order to back up your assertion (that would be, black cats do not constitute a vast majority).
I may do a statistical study and say: "At 95% confidence, (90 ± 7)% of cats are black".
You do your study too, and conclude that at 95% confidence only (80 ± 5)% of the cats are black. The confidence intervals overlap (even so slightly), so it's quite hard to say which statistics is right. Not to mention that we could accuse each other of having used a flawed method or an unrepresentative sample of the population.
I may also say "There are no white cats on the island".
This is another strong statement, but it's also negative, and this makes things much more complicated. For example, the only white cat may be hiding while you scout the island back and forth searching for it. So a doubt will always remain: you did not see any white cat because there is none, or because you were unable to spot the few present?
Generally, a strong negative statement is rather dishonest intellectually, because of this unresoluble doubt. Not always, sometimes a negative statement is OK; it depends from the context. For example, "There are no electrons with positive charge" is a honest statement, because those particles with positive charge and mass equal to the electron's mass are called positrons.
And all the above supposing that we both are being honest - or at least honest enough.
We may both play dirty, and things will get much more complicated.
For example, when you produce one grey cat I may insinuate that you did not find it on the island, but brought it from the mainland.
I can refuse to agree on a common definition of "vast majority" and thus make discussions about it meaningless.
I may manipulate my statistics, and/or accuse you to do so - this is different from the case discussed above, because the idea of manipulation implies a malicious will; not good-faith mistakes.
Or, when trying to prove the existence of at least one white cat you may publish a dark, out-of-focus, low- resolution photograpy showing a white indistinct blur, and insist that it's the infamous white cat. But it is impossible to tell exactly what the white blur is - accepting that the picture was indeed taken on the island. But when asked to produce better evidence, you say that it's not possible, the white cat won't show itself again but anyway you believe it exists and I should trust you. But my mate Chris says that he lost his white rabbit on the island, just a few hours before the photo was taken...
Pressed further, you then state that the white cat was kidnapped by the Evil Secret Service after you took the picture, because the son of Big Oil Corporation's CEO likes to have his summer holiday on the island, but he loathes white cats and so the CEO used his political connections to have the few remaining white cats kidnapped and killed by the ESS. And save the white cats from the capitalist oppression, too. (It does not make sense, but it isn't very different from popular conspiracy theories).
This is just a fanciful and at times intentionally silly example, but it is based on the rules of logic and, peripherally, set theory. And if you look closely, you may find that it bears some relation with real events. Saying that "There were no WMDs in Iraq!" is isomorphic with saying "There are no white cats on the island".
Comments (0)
June 26, 2005
Process Control
A while ago I wrote of process monitoring, and now the time has come for an article about how to control chemical/industrial processes.
Process control implies to monitor the process paramenters, compare them with the setpoints, decide if action is required and take the appropriate action. This cycle can be performed in different ways: with simple electrical circuits (or even mechanical devices); with more complex electronics and finally with complex computerized systems that can take into account several parameters and their interactions. Sometimes humans are included in the loop, but there are drawbacks: the reponse time of a human is slow, and watching indicators waiting for an alarm is an incredibily tedious job, that can easily cause attention drops. Electronic circuits never get bored, instead.
The simplest system, conceptually, is an electric heater, so let's deal with it first.
An electric heater is a resistor, a coil of high resistivity wire or a rod of SiC, that will produce a great amount of heat when electric current passes through it.
The simplest control system is an on/off thermostat, such as the ones used for central heating: in this case, the heating elements are either on at full power when the temperature is below the setpoint, and off from the setpoint upward. This system, when used with electric heaters, is too crude: temperature initially overshoots sensibly the setpoint. So, better electronic controllers have been built; these will turn off the power before reaching the setpoint in order to reduce the overshoot.
But the most advanced controllers are called PID: proportional, integral, derivative. These can adjust the outpust power from 0 to 100% on the basis of the variation with time of the error - defined as the difference between setpoint and measurement (this is accomplished using electronics circuits for data processing and particular transormers and solid-state relays for power regulation). For example, my furnace has a PID controller, and when I turn it on I can notice that the heating power is 100% initially, then it decreases when the temperature gets closer to the setpoint and when the setpoint is reached only short bursts of low power are required to mantain the correct temperature. The internal parameters of the controller can be adjust manually or automatically for that specific furnace, reactor and process conditions (nature and flow of the reactants) and when this tuning process is completed, the furnace will work optimally.
If the system to control is a heat exchanger (another device widely used in industry), the controller(s) will open and close metering valves in order to adjust the flow of heating or cooling fluid. Similarly, the amount of heat produced by a gas burner can be regulated varying the flow of gas feed.
In mass flow controllers, the signal from the flow measuring element is processed by electronic circuits, or software for certain models, and compared with the setpoint (that can be entered by turning a potentiometer or typing a value in the software): an output signal is thus generated, and this signal pilotes a metering valve that will provide the correct flow.
Instead, pressure regulators are mostly mechanical: semplifying, the pressure of the gas (or liquid) acts against a regulable spring, and the valve opens only when the forces are balanced. Pressure regulators, back pressure regulators and relief valves all use variations of the basic design. There are also electronic pressure regulators, in which a valve is opened electrically according to the signal from a pressure transducer.
All control systems have a response time that is never zero: the electrical signals need time to travel along the wires, then to be processed and to travel back to the actuator or device in the plant. This is a minor problem for research applications where cables are no more than a few meters long, but in industry, where cables (called fieldbuses) are easily longer than 100 m the transmission time needs to be taken into account - not to mention the problem of electromagnetic interference, that is bigger for longer cables*.
All this and other factors cause the measurement to oscillate around the setpoint; good controllers will rapidly damp the oscillations to a minimal level. Less good ones cannot damp the oscillations completely, and in unfurtunate cases a positive feedback loop can occur and the oscillations will actually be reinforced with potentially damaging consequences.
Designing control systems is quite a difficult job, and while small research reactors can succesfully be controlled with off-the-shelf instruments (like this), petrochemical and other plants need custom-made ones, which also comprehend dedicated computers and fail-safe software; not your basic Windows (or Linux, for that matter) prone to crash too often. Just to name a few names, the big companies in this business are the likes of Honeywell and Siemens.
*Indeed, modern refinery control systems use fiber optics for data transmission, because they are resistant to EMI and do not constitute a fire/explosion hazard. Instead, traditional copper conductors must run inside nitrogen-filled steel pipes (to keep flammable gases and vapours out), junction boxes and switchboxes in order to reduce the explosion hazard - one can only imagine the cost and complexity of that.
Comments (0)
Process control implies to monitor the process paramenters, compare them with the setpoints, decide if action is required and take the appropriate action. This cycle can be performed in different ways: with simple electrical circuits (or even mechanical devices); with more complex electronics and finally with complex computerized systems that can take into account several parameters and their interactions. Sometimes humans are included in the loop, but there are drawbacks: the reponse time of a human is slow, and watching indicators waiting for an alarm is an incredibily tedious job, that can easily cause attention drops. Electronic circuits never get bored, instead.
The simplest system, conceptually, is an electric heater, so let's deal with it first.
An electric heater is a resistor, a coil of high resistivity wire or a rod of SiC, that will produce a great amount of heat when electric current passes through it.
The simplest control system is an on/off thermostat, such as the ones used for central heating: in this case, the heating elements are either on at full power when the temperature is below the setpoint, and off from the setpoint upward. This system, when used with electric heaters, is too crude: temperature initially overshoots sensibly the setpoint. So, better electronic controllers have been built; these will turn off the power before reaching the setpoint in order to reduce the overshoot.
But the most advanced controllers are called PID: proportional, integral, derivative. These can adjust the outpust power from 0 to 100% on the basis of the variation with time of the error - defined as the difference between setpoint and measurement (this is accomplished using electronics circuits for data processing and particular transormers and solid-state relays for power regulation). For example, my furnace has a PID controller, and when I turn it on I can notice that the heating power is 100% initially, then it decreases when the temperature gets closer to the setpoint and when the setpoint is reached only short bursts of low power are required to mantain the correct temperature. The internal parameters of the controller can be adjust manually or automatically for that specific furnace, reactor and process conditions (nature and flow of the reactants) and when this tuning process is completed, the furnace will work optimally.
If the system to control is a heat exchanger (another device widely used in industry), the controller(s) will open and close metering valves in order to adjust the flow of heating or cooling fluid. Similarly, the amount of heat produced by a gas burner can be regulated varying the flow of gas feed.
In mass flow controllers, the signal from the flow measuring element is processed by electronic circuits, or software for certain models, and compared with the setpoint (that can be entered by turning a potentiometer or typing a value in the software): an output signal is thus generated, and this signal pilotes a metering valve that will provide the correct flow.
Instead, pressure regulators are mostly mechanical: semplifying, the pressure of the gas (or liquid) acts against a regulable spring, and the valve opens only when the forces are balanced. Pressure regulators, back pressure regulators and relief valves all use variations of the basic design. There are also electronic pressure regulators, in which a valve is opened electrically according to the signal from a pressure transducer.
All control systems have a response time that is never zero: the electrical signals need time to travel along the wires, then to be processed and to travel back to the actuator or device in the plant. This is a minor problem for research applications where cables are no more than a few meters long, but in industry, where cables (called fieldbuses) are easily longer than 100 m the transmission time needs to be taken into account - not to mention the problem of electromagnetic interference, that is bigger for longer cables*.
All this and other factors cause the measurement to oscillate around the setpoint; good controllers will rapidly damp the oscillations to a minimal level. Less good ones cannot damp the oscillations completely, and in unfurtunate cases a positive feedback loop can occur and the oscillations will actually be reinforced with potentially damaging consequences.
Designing control systems is quite a difficult job, and while small research reactors can succesfully be controlled with off-the-shelf instruments (like this), petrochemical and other plants need custom-made ones, which also comprehend dedicated computers and fail-safe software; not your basic Windows (or Linux, for that matter) prone to crash too often. Just to name a few names, the big companies in this business are the likes of Honeywell and Siemens.
*Indeed, modern refinery control systems use fiber optics for data transmission, because they are resistant to EMI and do not constitute a fire/explosion hazard. Instead, traditional copper conductors must run inside nitrogen-filled steel pipes (to keep flammable gases and vapours out), junction boxes and switchboxes in order to reduce the explosion hazard - one can only imagine the cost and complexity of that.
Comments (0)
Test
Yes! Blogger Images does work, no more hassles with Hello!
What's in this pic? Well, it's the landscape from a mountain top that I reached riding my bike.
In unrelated developments, I also added the Italian blog The Right Nation.
Comments (0)
June 23, 2005
Deltas and Ratios
In mathematics, often the difference between two quantities is written with the Greek letter Delta:
Δ(x) = x2 - x1
Being it a difference, it tells little or nothing about the absolute values of x1 and x2; there is the same difference (90) between 100 and 10 as there is between 100100 and 100010 although in the second case the numbers are 1000 times bigger.
So, recently I read a leaflet inviting people to join the anti-G8 protests, and this leaflet said "the gap between the rich and the poor is getting ever wider". For argument's sake, suppose that this statement is both true and accurate; however it tells nothing about the baseline - or how poor are the poor. If anyone has enough income to live a decent life, what's wrong with some people being filthy rich? Nothing, unless you are a socialist or even worse a communist (I think in this case it's a difference of degree more than kind).
To make a practical example: there is a bigger income gap between Bill Gates and me than between me and a Brazilian farmer, but my living standard is much better than the Brazilian farmer. The income (or wealth) gap is almost meaningless in any serious discussion about poverty - unless you have an agenda, that agenda being a more "just" distribution of wealth.
The ratio between two different quantities generally has no specific name, but it can be called R:
R = x2 / x1
Again, also R says little about absolute values: 10/5 is equal to 1000 000/500 000 (the result is 2, if you wonder). Update 24/06: Probably in this case it would be better to say that a number, even if big, can be a rather small fraction of a huge one. But the emotional impact of a number with many zeroes is stronger.
So, this morning I looked at The Indipendent's first page and it featured alarming news: electric and electronic appliances left on standby consume so much energy to cause the emission of 1 Mt of carbon dioxide per year in Britain alone. This figure seems big, and the comparisons (enough energy to power Birmingham etc) reinforce the idea. But then let's look at the ratio, as published in the same article: approaching 1% of the nation's total.
Yes, 1%; one hundredth; in science when we can calculate a quantity with a 1% error it's rather good (it can be better, but even worse).
And what's being proposed to solve this problem? Regulations, of course, and even international ones.
Now, I think that turning off (not just standby) appliances when not in use is a good idea, and it takes only minimal time and effort to do it - when the appliance has a true ON/OFF button; some do not. I turn devices off when not in use (TV and computer monitors especially), and try to keep lights off when not required. But I wouldn't beat my chest about 1% of the total - especially considering that there is still a great uncertainty about the exact role of carbon dioxide emissions in the global warming.
On the other hand, I know personally people who are much more environmentalist (you know, the "No war for oil" types) but also waste electricity at every turn: computer monitors left on for hours even when not in use; they keep all lights always on even if nobody needs them etc. Or, they use a lot of candles: where does paraffin wax come from, in their opinion?? Update: Now I recall, my ex-flatmate kept the central heating on at max all day - but his room's window open too!
Comments (3)
Δ(x) = x2 - x1
Being it a difference, it tells little or nothing about the absolute values of x1 and x2; there is the same difference (90) between 100 and 10 as there is between 100100 and 100010 although in the second case the numbers are 1000 times bigger.
So, recently I read a leaflet inviting people to join the anti-G8 protests, and this leaflet said "the gap between the rich and the poor is getting ever wider". For argument's sake, suppose that this statement is both true and accurate; however it tells nothing about the baseline - or how poor are the poor. If anyone has enough income to live a decent life, what's wrong with some people being filthy rich? Nothing, unless you are a socialist or even worse a communist (I think in this case it's a difference of degree more than kind).
To make a practical example: there is a bigger income gap between Bill Gates and me than between me and a Brazilian farmer, but my living standard is much better than the Brazilian farmer. The income (or wealth) gap is almost meaningless in any serious discussion about poverty - unless you have an agenda, that agenda being a more "just" distribution of wealth.
The ratio between two different quantities generally has no specific name, but it can be called R:
R = x2 / x1
Again, also R says little about absolute values: 10/5 is equal to 1000 000/500 000 (the result is 2, if you wonder). Update 24/06: Probably in this case it would be better to say that a number, even if big, can be a rather small fraction of a huge one. But the emotional impact of a number with many zeroes is stronger.
So, this morning I looked at The Indipendent's first page and it featured alarming news: electric and electronic appliances left on standby consume so much energy to cause the emission of 1 Mt of carbon dioxide per year in Britain alone. This figure seems big, and the comparisons (enough energy to power Birmingham etc) reinforce the idea. But then let's look at the ratio, as published in the same article: approaching 1% of the nation's total.
Yes, 1%; one hundredth; in science when we can calculate a quantity with a 1% error it's rather good (it can be better, but even worse).
And what's being proposed to solve this problem? Regulations, of course, and even international ones.
Now, I think that turning off (not just standby) appliances when not in use is a good idea, and it takes only minimal time and effort to do it - when the appliance has a true ON/OFF button; some do not. I turn devices off when not in use (TV and computer monitors especially), and try to keep lights off when not required. But I wouldn't beat my chest about 1% of the total - especially considering that there is still a great uncertainty about the exact role of carbon dioxide emissions in the global warming.
On the other hand, I know personally people who are much more environmentalist (you know, the "No war for oil" types) but also waste electricity at every turn: computer monitors left on for hours even when not in use; they keep all lights always on even if nobody needs them etc. Or, they use a lot of candles: where does paraffin wax come from, in their opinion?? Update: Now I recall, my ex-flatmate kept the central heating on at max all day - but his room's window open too!
Comments (3)
June 22, 2005
In Una Galassia Lontana Lontana
C'era gente che non capiva una fava di tattica militare - peggio di Vittorio Zucconi, pure.
Si, sono andato a vedere Guerre Stellari Episodio 3 - ed il film mi ha lasciato piuttosto freddo. E mi sono ritrovato a parteggiare per Anakin Skywalker, non quei pistoloni di Jedi.
Comunque, parliamo di tattica militare: evidentemente in quella galassia hanno una tecnologia talmente avanzata da costuire piccole navette private che possono decollare da un pianeta, entrare in orbita, raggiungerne un altro e ridecollare senza nemmeno dover fare rifornimento di carburante. Notevole, davvero.
Ma nonostante questo, non hanno missili, non hanno bombe di precisione. Azzo, nemmeno hanno velivoli da supporto ravvicinato! A quanto pare, l'unica tattica conosciuta é la carica frontale di fanteria. Sulla Terra abbiam smesso di farle dopo la Prima Guerra Mondiale, quando é stato constatato che la carica frontale non poteva nulla contro le mitragliatrici (i russi peró hanno continuato anche piú tardi - proprio uno rispettoso della vita umana, Stalin). Ma forse nella Galassia Lontana Lontana nemmeno hanno mitragliatrici degne di tale nome; solo pistole laser che sembrano piuttosto deboli, tranne quando la sceneggiatura richiede altrimenti. Una bella granata da 155mm con spoletta di prossimitá potrebbe spazzare via Cloni o Androidi a decine in un solo colpo.
Non esistono nemmeno carri o blindati, e proprio zero armi pesanti - gli Jedi possono fare i fighi con le loro spade laser, ma vorrei vedere come se la cavano in un fuoco incrociato di RPG. O sotto un bombardamento di mortaio da 80mm.
Tu sai che i tuoi nemici sono tutti concentrati in una specie di pozzo, senza armi antiaeree. Visto che tu sei il cattivo e spietato figuro, la cosa piú logica da fare sarebbe lanciare qualche migliaio di bombe dentro il suddetto pozzo - o magari una bella nucleare - e poi riempirlo di terra e cemento. Invece no, l'esercito dei Cloni ci deve andare dentro e combattere palmo a palmo.
Per non parlare del Generale Sofferenza (General Grievous in inglese), che di fronte ad Obi-Wan estrae quattro spade laser. Figo, ma se avesse tirato fuori quattro venerabili MG42 sarebbero stati cazzi molto piú amari per Obi-Wan. Anche con quattro calibro 12 caricati a pallettoni; e se proprio avesse voluto esagerare, perché non un lanciafiamme o due?
Ed i Cloni nemmeno hanno bombe a mano, pare. Cosí, quando avvistano uno Jedi armato di spada laser ed incazzato come una biscia, invece di mettersi al riparo e tirargli qualche granata, lo attaccano frontalmente e si fanno massacrare. Azzo, perfino gli jihadisti in Iraq sono piú competenti - dopo che quelli stupidi sono stati uccisi.
Gli Androidi poi, non parliamo; solo Sofferenza é un tipo abbastanza duro; gli altri sono soltantocarne carta stagnola da cannone o qualsiasi altra arma piú potente di una pistola ad aria compressa.
Comments (1)
Si, sono andato a vedere Guerre Stellari Episodio 3 - ed il film mi ha lasciato piuttosto freddo. E mi sono ritrovato a parteggiare per Anakin Skywalker, non quei pistoloni di Jedi.
Comunque, parliamo di tattica militare: evidentemente in quella galassia hanno una tecnologia talmente avanzata da costuire piccole navette private che possono decollare da un pianeta, entrare in orbita, raggiungerne un altro e ridecollare senza nemmeno dover fare rifornimento di carburante. Notevole, davvero.
Ma nonostante questo, non hanno missili, non hanno bombe di precisione. Azzo, nemmeno hanno velivoli da supporto ravvicinato! A quanto pare, l'unica tattica conosciuta é la carica frontale di fanteria. Sulla Terra abbiam smesso di farle dopo la Prima Guerra Mondiale, quando é stato constatato che la carica frontale non poteva nulla contro le mitragliatrici (i russi peró hanno continuato anche piú tardi - proprio uno rispettoso della vita umana, Stalin). Ma forse nella Galassia Lontana Lontana nemmeno hanno mitragliatrici degne di tale nome; solo pistole laser che sembrano piuttosto deboli, tranne quando la sceneggiatura richiede altrimenti. Una bella granata da 155mm con spoletta di prossimitá potrebbe spazzare via Cloni o Androidi a decine in un solo colpo.
Non esistono nemmeno carri o blindati, e proprio zero armi pesanti - gli Jedi possono fare i fighi con le loro spade laser, ma vorrei vedere come se la cavano in un fuoco incrociato di RPG. O sotto un bombardamento di mortaio da 80mm.
Tu sai che i tuoi nemici sono tutti concentrati in una specie di pozzo, senza armi antiaeree. Visto che tu sei il cattivo e spietato figuro, la cosa piú logica da fare sarebbe lanciare qualche migliaio di bombe dentro il suddetto pozzo - o magari una bella nucleare - e poi riempirlo di terra e cemento. Invece no, l'esercito dei Cloni ci deve andare dentro e combattere palmo a palmo.
Per non parlare del Generale Sofferenza (General Grievous in inglese), che di fronte ad Obi-Wan estrae quattro spade laser. Figo, ma se avesse tirato fuori quattro venerabili MG42 sarebbero stati cazzi molto piú amari per Obi-Wan. Anche con quattro calibro 12 caricati a pallettoni; e se proprio avesse voluto esagerare, perché non un lanciafiamme o due?
Ed i Cloni nemmeno hanno bombe a mano, pare. Cosí, quando avvistano uno Jedi armato di spada laser ed incazzato come una biscia, invece di mettersi al riparo e tirargli qualche granata, lo attaccano frontalmente e si fanno massacrare. Azzo, perfino gli jihadisti in Iraq sono piú competenti - dopo che quelli stupidi sono stati uccisi.
Gli Androidi poi, non parliamo; solo Sofferenza é un tipo abbastanza duro; gli altri sono soltanto
Comments (1)
June 21, 2005
Variazioni
Changes
Ho deciso di cambiare l'indirizzo e-mail per la corrispondenza del sito, e mi sono pure iscritto a Tocqueville, l'aggregatore dei blog liberal-conservatori italiani. E poi, un altro esperimento: ho deciso di provare ad aprire i commenti a chiunque. Ma comportatevi bene, perché ci metto cinque minuti scarsi a chiudere di nuovo se le cose vanno a ramengo...
I decided to change the e-mail address for my website mail, and I also signed up with Tocqueville, the aggregator of Italian liberal-conservative blogs. And, I'll also try and open comments to anyone. But behave, because it will take less than five minutes to close the comments again if things get out of hand.
Aggiornamento 22/06: Come ho potuto dimenticare di aggiungere Tocqueville ai miei collegamenti nella barra?? Comunque ora l'errore é rimediato.
E poi, ecco spiegato (in inglese) cosa é un liberal-conservatore - non condivido al 100% tutte le posizioni di questo articolo, ma penso che sia la descrizione migliore.
Comments (3)
Ho deciso di cambiare l'indirizzo e-mail per la corrispondenza del sito, e mi sono pure iscritto a Tocqueville, l'aggregatore dei blog liberal-conservatori italiani. E poi, un altro esperimento: ho deciso di provare ad aprire i commenti a chiunque. Ma comportatevi bene, perché ci metto cinque minuti scarsi a chiudere di nuovo se le cose vanno a ramengo...
I decided to change the e-mail address for my website mail, and I also signed up with Tocqueville, the aggregator of Italian liberal-conservative blogs. And, I'll also try and open comments to anyone. But behave, because it will take less than five minutes to close the comments again if things get out of hand.
Aggiornamento 22/06: Come ho potuto dimenticare di aggiungere Tocqueville ai miei collegamenti nella barra?? Comunque ora l'errore é rimediato.
E poi, ecco spiegato (in inglese) cosa é un liberal-conservatore - non condivido al 100% tutte le posizioni di questo articolo, ma penso che sia la descrizione migliore.
Comments (3)
June 20, 2005
Warfare State
(The title comes from here)
Today I found this story on LGF, one that would give me the chills - if my office wasn't this hot. MEMRI uncovers a Syrian historian, G. 'Attiyya, declaring that:
But this is not news. The news is that if we take this assertion to its extreme logical and rational consequances, we can conclude that Palestinian women (especially the pregnant ones) are military assets, being employed in the serial production of fighters. And military assets are legitimate targets in war.
It is also the destruction of a division that we (in the West) desperately try to keep meaningful: the one between combatants and non-combatants. In this evil view, the only purpose of children is to be raised and nurtured to hate and kill (Jews).
Yes it's monstruous. I almost despise myself for coming out with such idea. But it's better to face the ugly reality than to seek reassuring lies. The prime culprits of this are the Palestinian leaders themselves (remember Arafat and all his passion for martyred children?) who invented and nurtured this sick culture.
I don't think Israel should engage in a campaign of mothers' assassination, tho. First, it is morally repugnant. Second, it would sink Israel's reputation to unprecedented depths.
Third, there is another viable option: the separation, exclusion of Palestinians and their murderous intent from Israel. That is what is being done, and with success; hopefully it will be enough to lead the Palestinians to face their own failure, recognize defeat and ask for a true peace.
Comments (0)
Today I found this story on LGF, one that would give me the chills - if my office wasn't this hot. MEMRI uncovers a Syrian historian, G. 'Attiyya, declaring that:
The Palestinian woman’s womb is a factory for the conflict; it produces fighting children. After this fighting child is produced, he is taught: “This is your land, this is your country, you will fight for it, stand on it, and die for it.” Therefore, a very important connection exists between motherhood, land, and blood.This is horrible, in more than one way. First, it is the nth demonstration that Palestinian culture is rotten to the core, drenched in death and martyrdom cult. The whole Palestinian "identity" is not standing for something, but only against something - Israel and the Jews.
But this is not news. The news is that if we take this assertion to its extreme logical and rational consequances, we can conclude that Palestinian women (especially the pregnant ones) are military assets, being employed in the serial production of fighters. And military assets are legitimate targets in war.
It is also the destruction of a division that we (in the West) desperately try to keep meaningful: the one between combatants and non-combatants. In this evil view, the only purpose of children is to be raised and nurtured to hate and kill (Jews).
Yes it's monstruous. I almost despise myself for coming out with such idea. But it's better to face the ugly reality than to seek reassuring lies. The prime culprits of this are the Palestinian leaders themselves (remember Arafat and all his passion for martyred children?) who invented and nurtured this sick culture.
I don't think Israel should engage in a campaign of mothers' assassination, tho. First, it is morally repugnant. Second, it would sink Israel's reputation to unprecedented depths.
Third, there is another viable option: the separation, exclusion of Palestinians and their murderous intent from Israel. That is what is being done, and with success; hopefully it will be enough to lead the Palestinians to face their own failure, recognize defeat and ask for a true peace.
Comments (0)
Baking
It's hot in London these days. Yesterday (Sunday) it reached 33 C, and today is just a bit fresher. But walking down the streets isn't too bad anyway. And you can get a tan, rare thing in Britain.
It is bad on the buses: only the very newest ones have air conditioning (I think); on most buses AC is only a pipe dream, and simple ventilation is not scarce; it's next to nothing.
So every journey, except night or early morning is an agony of searing, stale, stuffy air carrying the smell of sweaty rather than unwashed bodies, the general dirt of the buses, and if you're unlucky enough the stench of some food or drink that a careless folk spilled on the floor.
And my lab is another place of torture: it has big windows facing south-west, and a certain number of furnaces and other devices always on. Today the temp in there is happily 33 - 34 C, and I have to work near my oven. I can't stand more than ten minutes in a row in there. Cooling of electric and electronic appliances can become a problem in these conditions, and indeed my colleague had to add a supplementary fan to stabilize his mass spectrometer.
But my office is not that better: it used to be cool, even cold in the past weeks. But now it's hotter than outside - cooler than the lab, still. Apparently the conditioning plant here is under the influence of some obscure and imprevedible force.
A beer, give me an icy Mexican lager!
Comments (0)
It is bad on the buses: only the very newest ones have air conditioning (I think); on most buses AC is only a pipe dream, and simple ventilation is not scarce; it's next to nothing.
So every journey, except night or early morning is an agony of searing, stale, stuffy air carrying the smell of sweaty rather than unwashed bodies, the general dirt of the buses, and if you're unlucky enough the stench of some food or drink that a careless folk spilled on the floor.
And my lab is another place of torture: it has big windows facing south-west, and a certain number of furnaces and other devices always on. Today the temp in there is happily 33 - 34 C, and I have to work near my oven. I can't stand more than ten minutes in a row in there. Cooling of electric and electronic appliances can become a problem in these conditions, and indeed my colleague had to add a supplementary fan to stabilize his mass spectrometer.
But my office is not that better: it used to be cool, even cold in the past weeks. But now it's hotter than outside - cooler than the lab, still. Apparently the conditioning plant here is under the influence of some obscure and imprevedible force.
A beer, give me an icy Mexican lager!
Comments (0)
June 19, 2005
Men's Stuff
Via Chizumatic, I found this picture:
Driving and riding fast give me an all special kind of thrill, that few other things can equate. Fighting maybe, but not for sport - a real fight is what it takes. Sex is a different thing, I have to say.
Indeed, when I go on holiday always one of the first things I do is take my car and do a bit of fast driving on a certain stretch of road with little traffic. Even better, I jump on my motorbike and race on some enduro track: that's even more exciting, because there is a much more direct connection between me and my motorbike, and enduro requires quick reaction to take the proper trajectory, avoid rocks, deep ruts and other unexpected obstacles on the tracks. Sometimes branches or bushes stretch across the way, thus I extend my leg or arm to fend them off on the move. And strength is needed to recover from the quite frequent upsets that can always happen. And sometimes you hit the ground, but there is no glory without pain; jump back on the bike and open that throttle even more, dammit! And the reward is when you reach the top of that mountain, after facing treacherous steep tracks of rock and mud, you take off your helmet wet with sweat and behold the landscape around, the silence of nature while adrenaline still flows in your blood.
Comments (0)
Driving and riding fast give me an all special kind of thrill, that few other things can equate. Fighting maybe, but not for sport - a real fight is what it takes. Sex is a different thing, I have to say.
Indeed, when I go on holiday always one of the first things I do is take my car and do a bit of fast driving on a certain stretch of road with little traffic. Even better, I jump on my motorbike and race on some enduro track: that's even more exciting, because there is a much more direct connection between me and my motorbike, and enduro requires quick reaction to take the proper trajectory, avoid rocks, deep ruts and other unexpected obstacles on the tracks. Sometimes branches or bushes stretch across the way, thus I extend my leg or arm to fend them off on the move. And strength is needed to recover from the quite frequent upsets that can always happen. And sometimes you hit the ground, but there is no glory without pain; jump back on the bike and open that throttle even more, dammit! And the reward is when you reach the top of that mountain, after facing treacherous steep tracks of rock and mud, you take off your helmet wet with sweat and behold the landscape around, the silence of nature while adrenaline still flows in your blood.
Comments (0)
June 18, 2005
In The Headlines
Yesterday's Evening Standard had "Europe: war on France" on its billboards. It was about time, I add.
While in Spain people aren't so enthusiast for Zapatero's leftist agenda (not the "anti-gay" spin in the headline, tho. Pure BBC).
And that's all folks, I cannot be late at the pub, can I?
Comments (0)
While in Spain people aren't so enthusiast for Zapatero's leftist agenda (not the "anti-gay" spin in the headline, tho. Pure BBC).
And that's all folks, I cannot be late at the pub, can I?
Comments (0)
June 16, 2005
Subjects And Talent
I'm a bit tired of writing political commentary. One of the reasons is that there will always be someone who won't like what I have to say. Someone will find me too soft, or to hawkish, or too "culturally imperialist". Or someone will call me a dhimmi if not a Nazi accomplice only because I refuse the "nuke'em all and let Allah sot'em out option" and because I do not think that anyone sporting a swastika should be shot on sight, or something like that.
No, I've not been flamed, but I came to understand that often I'm running into deeply held axioms, and this means there is no way to reach a synthesys of positions with my rethorical opponents. It's only a wearsome intellectual position struggle. I won't stop writing political commentary of course, but expect little of it.
I am also tired of pointing at the enemies of the Western civilization, and building arguments about what/who we are fighting against. I also want to know what we are fighting for, and for me it isn't strict Christianity and Judaism; it's liberal democracy in a state well separated from religion. It's also the pictures of scantily clad Asian women, peripherally.
The other point is that I write strictly on an inspiration basis. This means, when I find the proper inspiration, an article will almost write by itself (like this very one), quickly in its final form. I forced myself to write when not inspired, sometimes, but the results were usually poor. In these days, I'm not inspired at all for political commentary.
But if commentary is not my favourite subject, political activism is near the bottom of the list. I tried, even on this blog, but simply it doesn't work for me. I'm not the guy on stage giving a rousing speech; I'll be the chap who worked to put things together and to set up the soundsytem, and who drinks his beer in the backstage observing satisfied that is silent commitment contributed to the cause. Other people are cut for activism instead; one example is Stefania with her blogs Free Thoughts and Unpoliticallycorrect. She even had a column published on TCS! Congratulations, Stefania (with a pang of jealousy)! But as I said, I'm not talented for activism.
I maintain this blog mainly for myself, as a place where to write what I feel like writing. The second purpose I have is to sontribute spreading scientific and technical knowledge, because science is the only instrument we have to learn the truth about the material world in which we live. Once you've learnt the truth, you are free to take your own conclusions, but conclusions based on an incorrect model of reality and/or faulty logic will be wrong, no matter what.
Ok, to end this explanatory piece, a few additions: the Logical Fallacies; and a bunch of Italian blogs: Robinik, Astrolabio and M&A.
E per finire, qualche aggiunta al mio sito: i blogs italiani Robinik, Astrolabio ed M&A - tutti di orientamento conservatore (o dovrei dire vero-liberale?), naturalmente.
Comments (0)
No, I've not been flamed, but I came to understand that often I'm running into deeply held axioms, and this means there is no way to reach a synthesys of positions with my rethorical opponents. It's only a wearsome intellectual position struggle. I won't stop writing political commentary of course, but expect little of it.
I am also tired of pointing at the enemies of the Western civilization, and building arguments about what/who we are fighting against. I also want to know what we are fighting for, and for me it isn't strict Christianity and Judaism; it's liberal democracy in a state well separated from religion. It's also the pictures of scantily clad Asian women, peripherally.
The other point is that I write strictly on an inspiration basis. This means, when I find the proper inspiration, an article will almost write by itself (like this very one), quickly in its final form. I forced myself to write when not inspired, sometimes, but the results were usually poor. In these days, I'm not inspired at all for political commentary.
But if commentary is not my favourite subject, political activism is near the bottom of the list. I tried, even on this blog, but simply it doesn't work for me. I'm not the guy on stage giving a rousing speech; I'll be the chap who worked to put things together and to set up the soundsytem, and who drinks his beer in the backstage observing satisfied that is silent commitment contributed to the cause. Other people are cut for activism instead; one example is Stefania with her blogs Free Thoughts and Unpoliticallycorrect. She even had a column published on TCS! Congratulations, Stefania (with a pang of jealousy)! But as I said, I'm not talented for activism.
I maintain this blog mainly for myself, as a place where to write what I feel like writing. The second purpose I have is to sontribute spreading scientific and technical knowledge, because science is the only instrument we have to learn the truth about the material world in which we live. Once you've learnt the truth, you are free to take your own conclusions, but conclusions based on an incorrect model of reality and/or faulty logic will be wrong, no matter what.
Ok, to end this explanatory piece, a few additions: the Logical Fallacies; and a bunch of Italian blogs: Robinik, Astrolabio and M&A.
E per finire, qualche aggiunta al mio sito: i blogs italiani Robinik, Astrolabio ed M&A - tutti di orientamento conservatore (o dovrei dire vero-liberale?), naturalmente.
Comments (0)
June 13, 2005
The Most Tedious Job
Well, when I worked for a few weeks in a small and disorganized pasta factory, putting bags of pasta in a box for 8 hours rates pretty high.
But today I have to sift through a few datasets, each one about 600 entries long, in search of a certain number of entries data that must be erased in order to mantain synchronization between pressure and temperature logs. I really find difficult to imagine something more tedious; and tedium leads to boredom, and boredom leads to opening Explorer and pissing around reading blogs etc neglecting the tedious job, which would never get done.
Tomorrow sounds more interesting: my boss enlisted me to work at revamping a truly fantascientific-looking machine (in reality, it's used to observe the surface of materials).
Update 15/06: I noticed that boredom also leads to write in poor English, shees...
Comments (0)
But today I have to sift through a few datasets, each one about 600 entries long, in search of a certain number of entries data that must be erased in order to mantain synchronization between pressure and temperature logs. I really find difficult to imagine something more tedious; and tedium leads to boredom, and boredom leads to opening Explorer and pissing around reading blogs etc neglecting the tedious job, which would never get done.
Tomorrow sounds more interesting: my boss enlisted me to work at revamping a truly fantascientific-looking machine (in reality, it's used to observe the surface of materials).
Update 15/06: I noticed that boredom also leads to write in poor English, shees...
Comments (0)
June 12, 2005
Films, Anime
I read quite a lot of books, but recently it's 90% narrative. You know, essays, history and such generally require quite a lot of concentration and intellectual application, and in this period I don't have much of intellectual energies left after working. So I prefer to read something more escapist.
And, for entertainment I watch movies and anime. Since I bought a DVD player (that can also read DivX files...), I have to impose some restraint on myself, otherwise I'd fill my room with DVDs. I think DVD is a great invention: a compact but high-capacity, durable and easy to use support for images was needed. Indeed, the success of DVD is so overwhelming that the VHS will basically disappear in a few years, especially now that writable and re-writable DVDs and writers are affordable. Much as it happened with audio cassettes and CDs - but cassettes are stubbornly refusing to die. The reason is that while CD writers are rather cheap, cassette recorders are absolutely inexpensive and technologically almost primitive.
I am buying all Ghost In The Shell - Standalone Complex, and I'll have to buy the movie too. I have Nausicaa and Neon Genesis Evangelion - and when I go to the shop I really have to restrain myself; too much good stuff out there. Indeed, yesterday I went to buy GITS, but it was sold out.
So, I got Blood: The Last Vampire instead. It's a great anime, but it left me a bit disappointed. The all-digital animation and drawings are absolutely superb and left me with the eerie "more real than real" sensation. The Hercules and F-4s are rendered very very well. Also the music score and sound are top-notch, definitely. I have a nit to pick, tho: the B-52 has eight engines, not six! (What's a B-52 have to do with vampires? The story is set in the Yokota Air Base in 1966, and a B-52 is shown while taking off for a bombing mission in Vietnam).
The story... well, there isn't much of a plot: we only have this tough-as-nails girl Saya slashing and cutting her way with a Japanese sword through a number of hideous blood-drinking demons. And one guy unfortunate enough to be misidentified (Update 13/06: rewatching the film I realized the guy on the train was not misidentified). The whole movie has a dark atmosphere - there is no comic relief, no cute sidekicks. The story proceedes at a frantic pace from one riveting fight to another... and then it simply ends, without answering a lot of questions that have been raised. Saya is a vampire, the last of the "original" ones. But what are those other demons, and why she's on the hunt together with a bunch of American secret agents is not revealed.
The whole movie is only 48 minutes long, so it's not surprising that many things are left undeveloped. And it left me disappointed in the sense that it looked more like an extended preview than a complete story. Ah, Saya spends a lot of her screentime in a Japanese shcool uniform, for those interested. AnimeWorld reports that a sequel of Blood is in the works, and if it keeps up it will be another great anime. There is a website for this movie, too, and it contains some cool stuff but it's short on information. A TV series titled Blood+ will also air in Japan starting Oct 2005 - and this time Saya is a regular schoolgirl, at least at the beginning.
Speaking of cute sidekicks, it is almost a must for anime to have them. There are notable exceptions - Ghost In The Shell has nothing cute or comic; it's dark and gloomy from the first to the last second. But Standalone Complex introduces the Tachikomas, which are rather cute, chatty and offer comic relief - and also more or less serious considerations about Artificial Intelligencies and sentient machines. And things get completely mad in the short animation features Tachikoma Days (indeed, the opening animation says "Tachikoma-kun", that means Tachikoma-dear) at the end of each episode - the "bowling" scene in #5 is a riot of fun.
Still, the Tachikomas are first and foremost battle machines, strictly utilitarian and not accustomed to the needs of organic life; they are also armed and ready to open fire without esitation if required. All in all, my secret dream is to have a pet Tachikoma - no burglar is going to get past it, I tell you.
Comments (3)
And, for entertainment I watch movies and anime. Since I bought a DVD player (that can also read DivX files...), I have to impose some restraint on myself, otherwise I'd fill my room with DVDs. I think DVD is a great invention: a compact but high-capacity, durable and easy to use support for images was needed. Indeed, the success of DVD is so overwhelming that the VHS will basically disappear in a few years, especially now that writable and re-writable DVDs and writers are affordable. Much as it happened with audio cassettes and CDs - but cassettes are stubbornly refusing to die. The reason is that while CD writers are rather cheap, cassette recorders are absolutely inexpensive and technologically almost primitive.
I am buying all Ghost In The Shell - Standalone Complex, and I'll have to buy the movie too. I have Nausicaa and Neon Genesis Evangelion - and when I go to the shop I really have to restrain myself; too much good stuff out there. Indeed, yesterday I went to buy GITS, but it was sold out.
So, I got Blood: The Last Vampire instead. It's a great anime, but it left me a bit disappointed. The all-digital animation and drawings are absolutely superb and left me with the eerie "more real than real" sensation. The Hercules and F-4s are rendered very very well. Also the music score and sound are top-notch, definitely. I have a nit to pick, tho: the B-52 has eight engines, not six! (What's a B-52 have to do with vampires? The story is set in the Yokota Air Base in 1966, and a B-52 is shown while taking off for a bombing mission in Vietnam).
The story... well, there isn't much of a plot: we only have this tough-as-nails girl Saya slashing and cutting her way with a Japanese sword through a number of hideous blood-drinking demons. And one guy unfortunate enough to be misidentified (Update 13/06: rewatching the film I realized the guy on the train was not misidentified). The whole movie has a dark atmosphere - there is no comic relief, no cute sidekicks. The story proceedes at a frantic pace from one riveting fight to another... and then it simply ends, without answering a lot of questions that have been raised. Saya is a vampire, the last of the "original" ones. But what are those other demons, and why she's on the hunt together with a bunch of American secret agents is not revealed.
The whole movie is only 48 minutes long, so it's not surprising that many things are left undeveloped. And it left me disappointed in the sense that it looked more like an extended preview than a complete story. Ah, Saya spends a lot of her screentime in a Japanese shcool uniform, for those interested. AnimeWorld reports that a sequel of Blood is in the works, and if it keeps up it will be another great anime. There is a website for this movie, too, and it contains some cool stuff but it's short on information. A TV series titled Blood+ will also air in Japan starting Oct 2005 - and this time Saya is a regular schoolgirl, at least at the beginning.
Speaking of cute sidekicks, it is almost a must for anime to have them. There are notable exceptions - Ghost In The Shell has nothing cute or comic; it's dark and gloomy from the first to the last second. But Standalone Complex introduces the Tachikomas, which are rather cute, chatty and offer comic relief - and also more or less serious considerations about Artificial Intelligencies and sentient machines. And things get completely mad in the short animation features Tachikoma Days (indeed, the opening animation says "Tachikoma-kun", that means Tachikoma-dear) at the end of each episode - the "bowling" scene in #5 is a riot of fun.
Still, the Tachikomas are first and foremost battle machines, strictly utilitarian and not accustomed to the needs of organic life; they are also armed and ready to open fire without esitation if required. All in all, my secret dream is to have a pet Tachikoma - no burglar is going to get past it, I tell you.
Comments (3)
June 10, 2005
Out of Time, Out of Touch
Look at this poster that appeared in one of my college's boards:
Thus, I decided to add a little perspective:
Looks rather better now, doesn't it? (Thanks to Protest Warrior)
I did the addition last night, and it's still up - consider that Marxists often believe in "Freedom of Speech for Me, But not for Thee".
Comments (0)
Thus, I decided to add a little perspective:
Looks rather better now, doesn't it? (Thanks to Protest Warrior)
I did the addition last night, and it's still up - consider that Marxists often believe in "Freedom of Speech for Me, But not for Thee".
Comments (0)
June 08, 2005
A Practical Example
Remeber my article on process monitoring? I thought it would be better to give a practical example of a case of temperature monitoring. The latest addition to my high-pressure adsorption rig is a thermocouple datalogger - a small USB device that will convert the thermocuple voltage signal in digital form that can be understood by the appropriate software. Data can then be exported to Excel (or another other spreadsheet) and plotted (the quality of the picture may not be the best: the conversion to JPG introduced a little distortion).
The core of the adsorption system (the two pressure vessels, control valves and related piping) is inside an oven for temperature control, and the violet and blue tracks represent the temperature inside the two pressure vessels (in this case, the system was filled with carbon dioxide and possibly some air at atmospheric pressure). The yellow track represents the room temperature.
The room temperature is constant within 1 C, but shows short-period small oscillations: this happens because the thermocouple is small and highly sensible, and the recording device has a high resolution.
When the oven thermostat is set at 40 C, the temperature rises quickly, overshoots slightly the setpoint and then slowly settles. When the heating is turned off, temperature decreases slowly and almost linearly. One can notice that the tracks of the inner temperature are considerably smoother: the oven is insulated, and the metal of the vessels, tubes, valves, fittings and supports constitutes a sizable thermal mass that dampens effectively small temperature fluctuations. Also, low-pressure (and thus low-density) gases are not good thermal conductors.
Comments (0)
June 06, 2005
Sun At Work
I wrote quite a few posts in the past to point out the problems and weak spots of the renewable energy sources, and recently I realized a left out a technique for the use of solar energy that, instead, works pretty well.
I am talking about solar panels for water heating: these are feasible and rather cost-efficient. In my opinion, the reason is that hot water for domestic use doesn't need to be really hot: 60 C (140 F for the metrically-challenged persons) is enough, and even a temperature as low as 40 C is not useless. Instead, any decent steam turbine requires high-temperature superheated steam to work. Also, water is quite good for heat accumulation, because it is rather dense and has a high heat capacity (in other words, a little of water holds quite a lot of thermal energy) and a simple layer of cheap polyurethane foam constitutes a suitable insulation for accumulation tanks.
A solar panel is basically a coil of copper tube (which has a high thermal conductivity) painted black and palced inside a thermally insulated box with a glass pane on the front: the solar radiation thus collected will heat up a thermal exchange fluid (water + antifreeze, usually) circulating through the coil. This fluid is then forced to pass in another coil placed inside a tank, in order to transfer heat to the tap water. The whole system is simple, and its only moving part is a water circulation pump (plus a simple automated control system, but those are highly reliable nowadays), and it efficiency can be as high as 60%. In a place like Northern Italy, solar panels of the appropriate surface can produce all the hot water a household requires from May to October (depending from the weather), and some even during the coldest months (a gas or electric boiler is still required for support). The whole system with installation costs from 3 to 5 thousand Euros (IIRC) in Italy for a 6-room house*, but it will pay off rather quickly; if the solar panels are integrated in the house from the design stage the saving will be even higher.
But the beauty of solar water heating is that simpler solutions, to be used in the summer only, can be built by anyone with a little DIY skills and equipment: a coil of black plastic tube laid out on a rooftop can produce a considerable amount of hot water, and you can use your imagination to figure out other cases.
Solar power can be used for central heating too, but the problem with this is that central heating is most required on those short and often cloudy winter days which aren't exactly the best for collecting solar radiation. Many people experimented different solutions for solar heating: huge, thickly-insulated tanks of warm water; hot hair passed through brick structures (a design reminescent of certain accessory facilities of blast furnaces) etc, but the conclusion is that even the most elaborate (and not cheap) systems can provide at best three days (more or less) of autonomy without sun.
I'm rather skeptical towards solar central heating, especially considering the optimal performance of modern gas-fired boilers, but I am a big fan of solar panels for hot water, and I think that policies to boost their use are right-on.
* The European Union does subsidize up to 30% of the cost, but guess what: that's just enough to cover the bureocratic expenses...
Comments (2)
I am talking about solar panels for water heating: these are feasible and rather cost-efficient. In my opinion, the reason is that hot water for domestic use doesn't need to be really hot: 60 C (140 F for the metrically-challenged persons) is enough, and even a temperature as low as 40 C is not useless. Instead, any decent steam turbine requires high-temperature superheated steam to work. Also, water is quite good for heat accumulation, because it is rather dense and has a high heat capacity (in other words, a little of water holds quite a lot of thermal energy) and a simple layer of cheap polyurethane foam constitutes a suitable insulation for accumulation tanks.
A solar panel is basically a coil of copper tube (which has a high thermal conductivity) painted black and palced inside a thermally insulated box with a glass pane on the front: the solar radiation thus collected will heat up a thermal exchange fluid (water + antifreeze, usually) circulating through the coil. This fluid is then forced to pass in another coil placed inside a tank, in order to transfer heat to the tap water. The whole system is simple, and its only moving part is a water circulation pump (plus a simple automated control system, but those are highly reliable nowadays), and it efficiency can be as high as 60%. In a place like Northern Italy, solar panels of the appropriate surface can produce all the hot water a household requires from May to October (depending from the weather), and some even during the coldest months (a gas or electric boiler is still required for support). The whole system with installation costs from 3 to 5 thousand Euros (IIRC) in Italy for a 6-room house*, but it will pay off rather quickly; if the solar panels are integrated in the house from the design stage the saving will be even higher.
But the beauty of solar water heating is that simpler solutions, to be used in the summer only, can be built by anyone with a little DIY skills and equipment: a coil of black plastic tube laid out on a rooftop can produce a considerable amount of hot water, and you can use your imagination to figure out other cases.
Solar power can be used for central heating too, but the problem with this is that central heating is most required on those short and often cloudy winter days which aren't exactly the best for collecting solar radiation. Many people experimented different solutions for solar heating: huge, thickly-insulated tanks of warm water; hot hair passed through brick structures (a design reminescent of certain accessory facilities of blast furnaces) etc, but the conclusion is that even the most elaborate (and not cheap) systems can provide at best three days (more or less) of autonomy without sun.
I'm rather skeptical towards solar central heating, especially considering the optimal performance of modern gas-fired boilers, but I am a big fan of solar panels for hot water, and I think that policies to boost their use are right-on.
* The European Union does subsidize up to 30% of the cost, but guess what: that's just enough to cover the bureocratic expenses...
Comments (2)
The Deluge Continues
This picture is still drawing a lot of visitors to my weblog: if you use Google Image Search for "chiaki_152.jpg" it will return only four results, two of which from The Italian Version. What is still a mistery to me is the reason why people from all over the world seem so interested in Chiaki Kuriyama just now. Did she do something special to boost her popularity? Or is it just an infectious meme? I'd appreciate if some visitor would mind to drop me an explanatory e-mail.
I begin to understand what Tom means with his Search Engine Fun series...
Comments (0)
I begin to understand what Tom means with his Search Engine Fun series...
Comments (0)
June 04, 2005
One Addition
Still busy at work (do you think chemical reactions do care if it's Saturday?), so I'll be quick: Media Slander, a blog/website entirely dedicated to uncovering lies, falsehoods and rumors in the media regarding the War on Terror and military affairs at large. Such an effort was much needed, unfortunately.
Comments (0)
Comments (0)
June 03, 2005
Laws Of War*
No, I don't have time to write at length of this important subject. Finally I have set up a reactor, reduced the catalyst and now the whole thing is taking CO2 and H2 at the inlet and churning out small amounts of CO and water at the outlet. Nothing really innovative, but I have to start assessing the situation before telling whether different conditions cause any interesting change. This also means, get ready for a few more chemical engineering posts to come.
So, regarding the Laws of War, I'll cite the words of Wretchard:
* Yes, even the title is taken almost straight from Belmont Club... ain't very creative today.
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So, regarding the Laws of War, I'll cite the words of Wretchard:
If the objective function is to minimize the suffering of noncombatants, the first step must surely be to discriminate between the "innocent" and the "guilty", for when distinctions are not made obvious by the wearing of uniforms other methods must be substituted. The main driver of battlefieldRead and consider, before casting accusations here and there and weeping for infringed human rights.
humanitarianism is good intelligence. A terrorist battlefield sees far less force than the First War -- none of the rolling barrages of the Somme -- but compensates in frightfulness by using civilians as sandbags, and only intelligence and highly accurate targeting systems can focus violence on the
combatants and not the civilians. Only through intelligence can there be any hope of achieving the substantive aim of humanitarian war, which is the exclusion of the noncombatant from the violence of battle. Humanitarian law
then, should theoretically do everything in its power to enhance this process, just as in the past century, it highlighted the practices most likely to assist civilians given the battlefield modalities of the day. However, humanitarian law in its current form sometimes does the very opposite and hinders this process. A captured terrorist is only obliged to state his name, rank and serial number. Tom Friedman of the New York Times argues that Guantanamo Bay should simply be shut down because it is so contrary to humanitarianism.
[...]
What Mr. Friedman does not quantify is how many innocent civilians might
die from mistaken engagement, friendly fire, bad targeting and what have you, if an alternative means of obtaining intelligence is not found. Would it be greater or less than the hundred or so Jihadis said to have died in US custody? Would it matter to those who regard Gitmo as the anti-Statue of Liberty? This is not an argument for torture: there are more effective ways than hostile interrogation to obtain intelligence including spying, wiretapping, surveillance and tracing through bank accounts. But it is an argument to recast humanitarian law to allow the gathering and application of that intelligence. Much of the historical impact of humanitarian law stemmed directly from the ability to gather and apply intelligence to discriminate between combatants and noncombatants. The devices of open cities, clearly marked ambulances, zones of safe passage, armbands for humanitarian personnel, etc are usages whose practical utility has expired under the deceptions of terrorist warfare (bold mine), but their intent -- that of marking the limits of licit violence -- is sound. It is a distinction which can be based only on intellgence. Without that, humanitarian law is form without function on the modern terrorist battlefield, "a tale told by an idiot, full of sound and fury, signifying nothing".
* Yes, even the title is taken almost straight from Belmont Club... ain't very creative today.
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June 02, 2005
Go Chiaki Go
My referrals in the last few days are showing a lot of Google Image Search hits for the pictures of Chiaki Kuriyama I posted quite a while ago - well, my exposed skin project is bringing its fruits, although later than expected.
Anyway, for all ofus you Oriental feticists, here's some more of little Chiaki in a sexy pose!
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Anyway, for all of
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