 and Townsend streets that once held the wooden hut of Walts Diner, one of Delaney’s most now-otherworldly shots, found in a book that accompanies the exhibition. If Walt’s still existed, it would share the intersection with software behemoths Advent and Adobe.
Yet the tale of then and now is not simply a cleansed saga of raw capitalism triumphant, as the most simplistic political commentaries would have us believe.
A poignant glimpse of long-gone SoMa at the de Young show is Delaney’s shot from 1980 of a mustachioed man in jeans and leather jacket striding past a closed natural-foods grocery, a battered masonry industrial building across the way. It’s all too easy to imagine that the man died a few years later in the AIDS epidemic. Nor is it a leap to imagine the grocery and its neighbor restored to rough-hewn perfection, filled by startups.
Not so. The building at Howard and Russ streets that held the bulk grocery now holds a woman’s shelter. The one across the way is home to Swords to Plowshares, a nonprofit that works with troubled veterans. In the struggle to define the future neighborhood, the less-privileged found a way to stay on the scene.
Many aspects of today’s city are different than when Delaney paid $125 for her alleyway retreat. But an underlying aspiration — the quest to create or preserve diversity in all forms — remains strong. That persistence is a source of our ongoing tension, and a reason for optimism as well.
Place appears on Wednesdays. John King is The San Francisco Chronicle’s urban design critic. E-mail: jking@sfchronicle.com Twitter: @johnkingsfchron
Photo show
Janet Delaney: South of Market: Photographs and ephemera. Through July 19. De Young Museum, Golden Gate Park, S.F. (415) 750-3600..
A panel inspired by the exhibition — “Keeping San Francisco Alive: A Frank Conversation” — will be held Friday at 6 p.m. in Wilsey Court at the de Young.New Delhi: Human resource development minister Kapil Sibal has questioned the rationale behind faculty quotas at premier higher education institutions like the IITs, IIMs and central universities, contending that teacher reservations are premature as a concept.
Indicating a sharp difference in view with his predecessor Arjun Singh, Sibal argued against the utility of faculty quotas at present in an interview to The Telegraph today.
“You can only have quotas for teachers if there are enough people of the community concerned coming up through the system to take up those posts,” the HRD minister said.
He said faculty quotas would assist deprived sections only after an adequate number of students from these sections benefit from education reservations.
Quotas for students from scheduled castes and scheduled tribes have been in place for several decades now, but OBC reservations were implemented first only last year.
Sibal’s views resonate with the demand from IIT directors for no reservations, but appear in stark contrast to those held by Arjun, HRD minister in the previous UPA government.
They are also divergent from standard government policy.
Sources close to Sibal, who took over as HRD minister just three weeks ago, suggested that autonomous higher education institutions, including central universities like Delhi University, and the IITs were already exempted from faculty quotas.
But so far, both central universities and the IITs have been covered by faculty reservations for SCs, STs and OBCs under orders from the department of personnel and training (DoPT).
The IITs for several years claimed they were exempted from the quotas, but The Telegraph on December 6, 2007, revealed that the institutes did not enjoy any such exemption.
Arjun then ordered the IITs to follow faculty reservations. The sources closed to Sibal today revealed that Arjun had himself subsequently stayed the order to follow teacher reservations.
Last year, the DoPT moved a bill that made government job reservations a law — so far, these have been implemented through executive orders. But the bill exempted the IITs, IIMs and select central universities from faculty quotas.
This bill was passed in the Rajya Sabha but then opposed by members of the ruling UPA, like Ram Vilas Paswan, and was never introduced in the Lok Sabha.
The IITs and several other higher education institutions have, however, repeatedly demanded exemption from faculty quotas.
At most central universities, several teaching posts reserved for SC/ST candidates lie vacant because of inadequate applicants of required standards.
Sibal’s argument — that not enough candidates from backward communities are coming up through the education system — is generally accepted as the most plausible reason for these faculty vacancies.
The HRD minister said primary and secondary education would be his priorities, indicating that he would act to reduce examination pressure on school students.
“We must make sure that children and their parents are not traumatised by the kind of school examination system we have. Education must be entertaining and attractive to children,” Sibal said.
Asked about frequent clashes in recent years between the IIMs and the government over the fees charged by the premier B-schools, Sibal said he had not addressed the debate over autonomy yet.
The HRD minister indicated that he was likely to leave the IITs and IIMs alone but added a rider. “The IITs and IIMs are doing fairly well on their own. But autonomy does not mean a free licence,” Sibal said.There is a spike on the current waveform, and this weird voltage tail. Do you know what caused it ad if this is dangerous? I'm measuring the current using additional, separated CT, the oscilloscope has grounding disconnected. With 100 VDC on the bus I am able to get about 25 cm sparks (tuned the coil more or less). I'm grounding the secondary, heat sinks, GNDs of driver and minibridge to the same point. The socket's earthing is also connected to this point.
The phase leading works correctly, I'm able to set the ZCS.
The spike on the current waveform is probably just noise, try scoping the primary current with common mode filter. The voltage tail is due to recuperation of energy back to DC capacitors through IGBT diodes, it's perfectly normal. I would say your waveforms are actually quite perfect.
Why can those diodes cause problems? I used them to suppress any voltage spikes.
I'm glad that these waveforms are ok. But I'm a bit concerned about the spark length. At 100 VAC it is about 20-30 cm to a grounded rod, no corona discharges (at least I haven't seen any during the day).
Is it the energy coming back from secondary causing the tail shape?
Also, do you think that connecting the coil's own grounding to socket's ground is a good idea?
It's fine to use them to suppress voltage transients between G-E of your IGBTs because in case the voltage spike causes them to conduct, your GDT cannot provide much current to overheat them. But the current flowing in the bridge is in orders of 1000Amps! If the TVS starts to conduct, it will overheat quickly and fail short circuit which can and will destroy your IGBTs. Those transistors can take much more avalanche energy than the TVS diode. You would need many of them in parallel. (It also adds unnecessary capacitances and inductances to the bridge).
Not all the energy from the primary gets transferred to the secondary, the tail is caused by the leftover energy in the primary getting back to DC bus capacitors.
Than you for explanation. If that is the energy from the primary circuit, why the tail differs that much in shape with and without the secondary?
Do you have any idea what could be a cause of small arcing? I think my ground path is quite good, I put about 0.7 m of a rod into the soil nearby the coil.
I'm not sure, but that might be because with secondary in place, some energy still gets transferred to the secondary, which might change the shape? Not sure about this one.
That is probably the best way to ground the secondary coil. But again, I'm not sure what explains the small arcs.
Maybe you just run too short on-times (unlikely). Maybe your coil still needs some tuning (more likely).
The on-time was in the range of 100-200 us and about 30 BPS.
Ok, I managed to get 1 m long sparks at 100 VAC input, however they only occur when I put a grounded object as a target, no corona discharge. When I was trying to achieve longer sparks and moved the target a bit, some streamers hit the secondary (from toroid to secondary) slightly above the strike rail.
Are you using some breakout rod from the toroid?
Also, if your secondary got hit, it's an indication that you need bigger toroid to shape the electric field better for protection.
Yes, I’m using a sharp rod on the top of the toroid.
Even visually the toroid is a bit small, so it’s size actually could be a problem.
Well I don't know what's wrong with the arc size but the toroid definitely needs an upgrade. The toroid must distribute the electric field well enough to protect from any primary/secondary strikes.
I recommend you to stop with your experiments until you upgrade the topload to prevent any secondary or primary strikes which can be potentially destructive.
My rule of thumb is that the topload major diameter