text:
WALLA WALLA — A day after a pair of Whitman first-years surprised the rest of the conference, sophomore twins Courtney and Morgan Lawless did exactly what they were expected to do on Sunday. They won, and won, and won some more, as the Missionaries continued their best ever showing at the USTA/ITA Fall Regional championships.
Playing without three-year No. 1 singles player Alyssa Roberg in the singles bracket, Whitman still managed to match their two-semifinalist showing in last year's tournament.
Morning showers in Walla Walla wetted the outdoor tennis courts at Whitman College, but they did nothing to stop the Lawless twins.
After dropping just one game in advancing to the round of 16, second seed Courtney Lawless picked up where she left off in a 6-1, 6-0 victory over ninth-seeded Payton McGriff of Pacific Lutheran to advance to the quarterfinals, where she squared off with teammate Jenna Dobrin, and Lawless rolled to a 6-1, 6-2 victory to advance to the semifinals.
There, she will face Olivia Cornell of Lewis and Clark.
Fifth-seeded Morgan Lawless beat Whitworth's Taylor Pena 6-1, 6-2 to advance to the quarters, where she met Aurora Garrison in the match of the day.
After dropping just one game on her way to the round of 16, Garrison toppled Whitman's Kate Rubinstein 6-0, 6-3.
In the quarters, Morgan Lawless imposed her will in the first set, forcing Garrison to play her preferred baseline game. That didn't prevent Garrison from keeping the set close. The two traded breaks and holds until the set was knotted up at 6-6, but Morgan was able to handle the pressure better and won the tiebreaker and the set. Shortly thereafter, Morgan suffered a classic emotional letdown after the tense tiebreaker, and Garrison jumped out to a 0-3 lead in the second. Lawless battled back to 2-3, but Garrison held then broke to extend her lead to 2-5. From there, Lawless won three games to knot the second set at 5-5. She then finished the comeback by breaking a dispirited Garrison and holding to punch her ticket into the semifinals.
There, she will meet Willamette's Denise Poltavski.
After the Lawless twins were safely in the semifinals of the singles bracket, they returned to the court in the afternoon with their partners to continue their winning ways. Courtney and Roberg, the No. 1 seeds and defending champions, played textbook doubles in an 8-0 victory over a fifth-seeded team from Lewis and Clark of Olivia Cornell and Gillian Lowe.
In the semifinals, they finally ran into some stiff competition from Izzy Boris and Lisa Osepyan (also Pioneers), but they persevered for a 8-5 win to advance to the finals.
On the other side of the draw, Morgan Lawless and Jenna Dobrin met No. 3 seeds Aurora Garrison and Claudia Lew. Dobrin, who defeated Lew in singles, and Lawless, who defeated Garrison in singles, eliminated their respective opponents a second time, tallying a 8-5 upset victory. Their semifinal match was much less competitive, as they eased their way into the finals with an 8-1 victory over Beaumont and Inn from George Fox. The pair of semifinal victories ensured that a Whitman doubles team will win the regional tournament for a third year in a row.
Whitman's Kate Kunkel-Patterson and Maddy Webster teamed to bounce back from their main draw defeat to win the consolation bracket with a victory over Ecton and Watanbe of Linfield.
Play continued this morning on Whitman's outdoor courts, with semifinal singles matches starting at 9 a.m. The singles final will begin an hour after the completion of the semifinals, and Roberg and Courtney Lawless will play Dobrin and Morgan Lawless for the doubles crown when the singles tournament is over.
More like this story
Use the comment form below to begin a discussion about this content.


text:
Thanks for redeeming.{{else}}
Success! Thanks for repurchasing.{{/if}} {{else}} {{#if Expired}}
Increase my visibility!{{else}} {{#if IsMultiPack}}
{{#if HasMultiPack}} You have {{MultiPackCount}} top spot(s) left. Now loading you into the search listings... {{else}} You have used all top spots. Now loading you into the search listings... {{/if}}{{else}}
We are loading you into the search listing pages...{{/if}} {{/if}} {{/if}} {{/if}}
{{Current}} just saw you!{{/if}} {{#if LastTopSpotPurchaseIsMulti }} {{#if HasAnyTopSpot}}
{{#if HasFreeTopSpot }} {{ UnclaimedTopSpotFree }} Free {{/if}} {{#if HasPaidTopSpot }} {{#if HasFreeTopSpot }} & {{/if}} {{ MultiPackCount }} {{/if}} Top Spot{{#if Plural}}s{{/if}} Left{{else}}
0 Top Spot{{#if Plural}}s{{/if}} Left{{/if}} {{else}} {{#if HasFreeTopSpot }}
{{ UnclaimedTopSpotFree }} Top Spot{{#if Plural}}s{{/if}} Left{{/if}} {{/if}} {{else}} {{#if HasResults}}
{{Current}} see you now!{{else}} {{/if}} {{/if}}
You can now invite anyone to meet at your favorite Starbucks.
Limited-time feature
32 year old man | South Euclid, OH, USA | Seeking men 18-35 within 20 miles of Cleveland, OH
Change is the law of life. And those who look only to the past or present are certain to miss the future." - John F. Kennedy
I just a normal guy whose been single for about 3 months now. I'm looking to move on and meet someone new. However, I am still interested in friendship and just seeing what happens. I'm a graduate student at Purdue getting my MBA. I'm an active person and enjoy watching sports, listening to music. I often go out to local bars with my friends and enjoy a drink now and then and meeting new people. But I can also stay at home and sit on the couch watching a move. I'm not that picky when it comes to what I'm looking for in another guy. All I ask is honesty. Complete and total honesty, because that's what you'll get from me.
Camping , Business networking , Cooking , Dining out , Movies/Videos , Music and concerts , Exploring new areas , Nightclubs/Dancing , Playing cards , Political interests , Travel/Sightseeing , Watching sports , Wine tasting
Aerobics, Running, Soccer, Swimming, Tennis / Racquet sports, Walking / Hiking
I exercise 3-4 times per week.
I have Fish
I like Cats, Dogs, Horses
Middle of the Road
I enjoy going out to the local Lafayette and West Lafayette with my friends. Love taking walks around town and on campus. I regularly travel to Indy and Chicago.
Purdue University, West Lafayette, IN
Favorite bands right now are Black Key's, the Killers, Kings of Leon, and Lil' Wayne. Favorite TV shows are Weeds, True Blood, Two and a Half Men, and Dexter. I love cooking food, Italian and Surf and Turf are my favorite.
I love movies. I like watching random B movies late night on cable. Sports I watch on TV are track, tennis, swimming, golf, basketball. Enjoy the outdoors, camping, hoking, fishing. Hanging out with my friends and meeting new people are also good
I'm currently reading Haunted by Chuck Palahniuk.
Z{{Cta}} {{#if HasMoreInfo}} ?{{CtaSecondary}} {{/if}}
|What he is looking for
|5'7" (170cms)
|5'5" (165cms) to 6'8" (203cms)
|Body type:
|About average
|About average
|No preference
|No preference
|I'll tell you later
|No preference
|Social Drinker
|Social Drinker
|No preference
I'm currently a graduate student at Purdue. I also work part time at a Bar on campus.
|$25,001 to $35,000
|No preference
|Never Married
|Never Married
|Have kids:
|No preference
|Wants kids:
|Black / African descent
|Asian, East Indian, Latino / Hispanic, Middle Eastern, Pacific Islander, White / Caucasian
I'm actually mixed with Black, White, Native American, Hispanic, and Asian. A lot I know.
|Christian / Catholic
|No preference
While I am Catholic, I attend church semi-regularly, but I am open to people of other faiths or beliefs.
|English, Italian
|Bachelors degree
|Some college

subset: commoncrawl


text:
One embodiment of the present invention includes an optical cavity, a source to provide light to the optical cavity, a sensor to detect the light and generate a corresponding sensor signal, and a servo device including a feedforward input and a feedback input. Feedback from the sensor signal is provided to the servo device to regulate operation of the source at a frequency selected to generate an optical field resonating in the first mode in the cavity. An input device provides a control signal to a control input of the servo device that selectively alters operation of the light source to corresponding halt resonance in the first mode. An evaluation device is also included to evaluate decay of the optical field after resonance in the first mode is halted.
1. A method, comprising:
providing a light output from a laser device to an optical cavity to operate the cavity in a first resonant mode;
receiving a feedback signal representative of the light output with servo circuitry coupled to the laser device to stabilize operation of the cavity in the first resonant mode; and
halting the operation of the cavity in the first resonant mode in response to a control signal provided to the circuitry to evaluate decay of an optical field corresponding to the first resonant mode, said halting including performing feedforward control with the circuitry.
2. The method of
3. The method of
4. The method of
5. The method of
6. The method of
7. The method of
providing the feedback signal from a photodetector coupled to a first input of the servo circuitry; and
providing a feedforward control signal from a control source coupled to a second input of the servo circuitry.
8. The method of
changing operation of the laser in response to the control signal; and
alternating operation of the cavity between the first resonant mode and a second resonant mode.
9. A method, comprising:
operating an optical cavity responsive to light from a light source;
providing a feedback signal to a servo device to stabilize operation of the source at a selected frequency and a control signal to the servo device to adjust operating frequency of the light source, said providing including performing feedforward control with the servo device;
switching between different resonant modes of the cavity in response to the control signal; and
evaluating decay for each of the different resonant modes.
10. The method of
11. The method of
12. The method of
13. The method of
14. The method of
15. The method of
This invention was made with Government support under Contract Number DE-AC0676RLO1831. The Government has certain rights in the invention.
The present invention relates to cavity ringdown spectroscopy, and more particularly, but not exclusively relates to servo-switched frequency control of a light source for an optical resonator.
Cavity Ringdown Spectroscopy (CRDS) is a technique that, among other things, is directed to making absorption measurements with sensitivities that can be better than many other systems. In a typical CRDS system, the optical resonator includes two or more mirrors in an optical cavity aligned so that incident light circulates between them. The sample of absorbing material is placed in the cavity for interrogation. When input light to the resonator is discontinued, the radiant energy stored in the resonator decreases over time or "rings-down." For an empty cavity, the stored energy follows an exponential decay characterized by a ringdown rate that depends on the reflectivity of the mirrors, the separation between the mirrors, and the speed of light in the resonator. If an absorbing sample is placed in the resonator, the ringdown changes under appropriate conditions such that the resonator energy decays in a measurably different fashion than that for the empty resonator. A corresponding absorption spectrum for the sample is obtained by plotting the reciprocal of the ringdown rate versus the wavelength of the incident light. CRDS has been applied to numerous systems in the visible, ultraviolet, and infrared wavelength regimes. U.S. Pat. No. 5,528,040 to Lehmann is referred to as an additional source of background information concerning such techniques and is hereby incorporated by reference.
Current CRDS systems typically use a pulsed laser or a Continuous Wave (CW) laser. With a pulsed laser, the pulse length is generally much shorter than the ringdown time, so that less light enters the resonator compared to CW laser-based approaches. As a result, pulsed laser CRDS generally is less sensitive than CW laser CRDS. On the other hand, with CW laser CRDS, the need to switch the resonance off and on can be more complicated. Such switching is often performed with an Acousto-Optic Modulator (AOM), which can change the amplitude, frequency, and/or direction of the laser beam provided to the optical resonator, any one of which can be altered to initiate ringdown. Because an AOM provides a traveling wave with an acoustic grating that takes some time to form and dissipate, AOM switching typically has intrinsic speed limitations. These limitations can result in inaccuracies of the exponential fit of ringdown data, especially in the mid-wavelength to long-wavelength infrared ranges for which the AOM device is typically bigger and slower. For such wavelengths, the optical cavities of the corresponding resonators often have a lower resonance quality or "Q" factor, and correspondingly dissipate the decaying optical field faster during ringdown. In addition to drawbacks regarding the switching process, experiments of a more precise nature typically desire to "lock" the laser frequency to a selected resonant frequency, which is lost at the beginning of each ringdown interval and must be reacquired at the beginning of each excitation interval. These frequency lock techniques typically increase the complexity of the switching schemes used with CW laser CRDS.
Accordingly, there is a need for further contributions in this area of technology.
One embodiment of the present invention is a unique technique for performing cavity ringdown spectroscopy. Other embodiments include unique systems, devices, apparatus, and methods for controlling operation of an optical resonator.
A further embodiment includes means for generating a resonating optical field including a light source coupled to an optical cavity; means for stabilizing the resonating optical field by providing feedback to the light source with servo circuitry coupled to the light source; and means for evaluating decay of the optical field in response to a control signal input to the servo circuitry. This control signal input can switch operation between two or more different resonant modes of the optical cavity by corresponding switching between different frequencies of a CW laser form of the light source.
Another embodiment of the present invention includes performing cavity ringdown spectroscopy with an optical resonator and a laser device. The laser device is stabilized with circuitry that receives a feedback signal corresponding to detected output light of the laser device. The circuitry further receives a control signal that can correspondingly cause a change in one or more output characteristics of the laser device, such that a selected resonant mode of the resonator can be readily discontinued to evaluate ringdown. In one form, switching between different resonant modes of the resonator is performed. The characteristics determined with this system can include evaluation of reflectivity of one or more mirrors included in the resonator and/or evaluation of a sample placed in the resonator. The circuitry can be in the form of a servo device with a feed forward input receiving the control signal and a feedback input receiving the detected heterodyne signal between the cavity mode and the incident field from the laser. The laser device can be in the form of a current-controlled continuous wave type, such as a quantum cascade laser or laser diode variety. The optical resonator can include two or more mirrors in an optical cavity. The optical cavity can be arranged to selectively receive an analyte for evaluation.
Another embodiment includes operating an optical cavity responsive to light and providing a feedback signal from a servo device to stabilize operation of the light source at a selected frequency. A control signal is also provided to the servo device to adjust operating frequency of the light source. The embodiment further includes switching between different resonant modes of the cavity in response to the control signal and evaluating decay for each of the different resonant modes.
Still another embodiment of the present invention includes providing light from a laser device to an optical resonator to operate the resonator in a first resonant mode; receiving a feedback signal representative of the light output with servo circuitry coupled to the laser device to stabilize operation of the resonator in the first resonant mode; and halting the operation of the cavity in the first resonant mode in response to a control signal provided to the circuitry to evaluate decay of an optical field corresponding to the first resonant mode. The laser device can be of a current-controlled continuous wave type such as a quantum cascade laser or laser diode variety and/or the servo circuitry can include a feed forward arrangement for receiving the control signal. The optical resonator can include two or more mirrors in an optical cavity arranged to selectively receive an analyte for evaluation.
Accordingly, one object of the present invention is to provide a unique technique for performing cavity ringdown spectroscopy.
Another object is to provide a unique system, method, device, or apparatus for controlling operation of an optical resonator.
Other objects, embodiments, forms, features, advantages, aspects and benefits of the present invention shall become apparent from the detailed description and drawings included herein.
While the present invention may be embodied in many different forms, for the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications in the described embodiments, and any further applications of the principles of the invention as described herein are contemplated as would normally occur to one skilled in the art to which the invention relates.
Resonator 50 includes enclosure 51 and mirrors 52 and 54 disposed therein. Mirrors 52 and 54 are oppositely positioned and separated from one another along longitudinal axis L of resonator 50. Mirrors 52 and 54 are each of a concave, spherically-shaped type disposed in optical cavity 56 defined by enclosure 51. Typically, light from path 22 d enters cavity 56 at an angle such that it impinges on one of mirrors 52 and 54, which is aligned to reflect the incident light toward the other of mirrors 52 and 54 along separation distance 58, which is symbolically represented by a double-headed arrow. Accordingly, an optical field can be generated along the optical path of separation distance 58 between mirrors 52 and 54. Optical cavity 56 has transmission and reflection resonances at periodic frequencies for which the resulting optical field has a greater intensity than that provided by the incident light from laser 22. By tuning the input light from laser 22 to one or more of these frequencies, a resonance mode of the optical field can be stimulated.
System 20 further includes adjustment device 60. The length of separation distance 58 can be varied or "tuned" with device 60, which includes one or more elements to selectively translate mirror 54 along longitudinal axis L relative to mirror 52. Device 60 is responsive to a periodic input signal from signal source 62 to correspondingly adjust separation distance 58 at periodic rate. The change in distance 58 can likewise change resonance properties of cavity 56 providing a sweep for resonance over a selected range. In one form, device 60 is of an electromechanical variety that could include one or more piezoelectric actuators, and the signal from source 62 is of a sawtooth or triangle waveform type to provide the corresponding sweep. In other embodiments, a different aperiodic or periodic signal may be used, or device 60 and/or source 62 may be absent. Alternatively or additionally, in other embodiments variation in optical cavity resonances can be obtained by making adjustments to laser 22, and/or through different changes to resonator 50.
An output light beam from resonator 50 is provided along path 22 f to sensor 70 of system 20. Sensor 70 generates a signal corresponding to the intensity of the output light from resonator 50, which is provided along pathway 71 to evaluation device 72 of system 20. For a given resonance mode of optical cavity 56, the corresponding optical field takes a length of time to build-up and decay. The ringdown (decay) time is a function of the quality or "Q" of optical cavity 56. If optical cavity 56 contains a small quantity of a gaseous analyte that absorbs light at the operating wavelength, the Q of cavity 56 can be degraded, thus changing the peak cavity field and the ringdown (decay) time. Comparative measurements of this ringdown time with and without the analyte can result in a sensitive measurement of the optical field absorption by the analyte introduced into the cavity, which can be desirable for detecting concentration of one or more chemicals comprising the analyte. Alternatively or additionally, cavity ringdown can be used to measure very small looses or changes in the properties of reflective coatings of mirror 52 and/or mirror 54.
In further embodiments of system 20, sensor 30 can in addition to the laser control functions already outlined above, in fact be used to perform the above-described ringdown detection function of sensor 70. For this alternate embodiment, (sometimes called CW Heterodyne Ring Down), during the ringdown time of the optical cavity, the frequency of the incident laser light in path 22d which is in addition reflected from the front mirror 52 of optical cavity 56, is detuned from the light emanating from a decaying mode of the same. Light from the decaying mode propagates backward along path 22 d and is coincident with the direct reflection of the detuned incident field. This collinear field pair produces a heterodyne beat signal on sensor 30 in simultaneous addition to, but not in conflict with, other signals which can be produced to effect the locking of the laser 22 to another arbitrary mode of optical cavity 56. This heterodyne beat signal exhibits the same ringdown character as those generated by sensor 70, but in fact with more sensitivity.
Device 72 is depicted as a device which includes display 74 that schematically portrays the exponential decay of an optical field in cavity 56 that might result from discontinuing input light tuned to a desired resonant mode. It may also in fact be a computer which measures the ringdown time by performing real-time curve-fitting analysis to find the ringdown time constants, allowing this constant to be plotted in time as the cavity is scanned, showing the absorption features of the analyte by fluctuations in the ringdown time. Analyte source 80 selectively provides a substance (analyte) through an opening in enclosure 51 to cavity 56 for evaluation. Typically this analyte is in a gaseous form. The decay characteristics for one or more resonant modes of cavity 56 are determined and compared to "empty cavity" decay patterns. This comparison yields information useful in quantifying the analyte of interest.
Returning to beam splitter 28 of system 20, the light beam along path 22 e is monitored with optical sensor 30. Sensor 30 generates a signal along pathway 32 that is responsive to the intensity of the light it detects. Sensors 30 and 70 can be of the same or different types, including, but are not limited to, a photodiode, a photomultiplier tube, or a different variety as would occur to one skilled in the art.
System 20 also includes laser stabilization circuitry 40 in the form of servo 42. Servo 42 is further schematically depicted with feedback input 42 a and control input 42 b. Feedback input 42 a receives the sensor signal from pathway 32. Control input 42 b receives a control signal from control signal source 44 via pathway 46. Servo 42 outputs a laser control signal along pathway 48 to direct and regulate operation of laser 22.
It should be appreciated that two or more of laser 22, FI 24, AOM 26, beam splitter 28, sensor 30, sensor 70, resonator 50, device 60, source 62, device 72, source 44, and circuitry 40 can integrated together into a common unit along with any operatively connecting paths or pathways. Laser 22, device 72, source 62, source 44, sensor 30, sensor 70, or circuitry 40 can include one or more connections in common with one or more computing and/or control systems, power supplies, or the like. Although not shown, it should be appreciated that equipment to regulate one or more environmental characteristics of any or all the optical and/or electrical components of system 20 can be utilized; where such characteristics include, but are not limited to temperature, humidity, and pressure. Light paths 22 a-22 f can be through atmosphere, free space, one or more optical fibers, optical couplers, a combination of these, and/or such different arrangements as would occur to one skilled in the art to facilitate the desired light transmission. Pathways 32, 46, 48, and 71 are typically of an electrical conducting type to transmit corresponding electronic signals of a varying voltage and/or current variety.
During operation of system 20, stabilization circuitry 40 is responsive to feedback from sensor 30 to lock operation of laser 22 at a modulation frequency via pathway 48 selected to excite a desired resonance mode in optical cavity 56. This feedback path is symbolized by feedback loop F1 in FIG. 1. In one embodiment, feedback loop F1 is implemented by determining a frequency difference or "error" between the laser output light detected with sensor 30 and the desired frequency. For such an arrangement, circuitry 40 could be arranged to determine frequency from the signal at input 42 a and compare it to a target frequency, then generate a corrective output to laser 22 via pathway 48. Such an arrangement could be based on one or more differential amplifiers of an operational amplifier (opamp) variety or different type. In one opamp-based form, a negative opamp input could receive a voltage corresponding to the measured modulation frequency of light detected with sensor 30 and a positive input could receive a voltage level corresponding to a target modulation frequency (not shown).
Circuitry 40 is further arranged to receive a modulation frequency control signal from source 44 via pathway 46 at input 42 b. Circuitry 40 is arranged to respond to certain levels of the control signal to change the frequency of operation of laser 22. As a result, an optical field resonance in cavity 56 corresponding to a given frequency can be halted, permitting a ringdown of this resonance. In one embodiment, it has been found that frequency control in this manner can be implemented using feed forward circuitry FF1 associated with servo 42. Alternatively, circuitry 40 can respond to a change in the frequency control signal from source 44 such that it alters the modulation frequency of light output by laser 22 to provide a different mode of resonance in cavity 56. In this way, laser 22 and circuitry 40 can be arranged to switch operation of resonator 50 between two or more different cavity resonance modes to correspondingly provide different ringdown (decay) measurements. Accordingly, an alternating (AC) ringdown technique can be performed which switches between two cavity modes, one of which is within and the other of which is outside the absorption band of the analyte. This approach allows the baseline comparison and the analyte data to be measured in rapid succession, which typically increases the signal-to-noise ratio of the system. Alternatively or additionally, the switching of modulation frequencies with circuitry 40 optionally eliminates the need for switching with an AOM type device 26. Indeed, while AOM 26 could alternatively or additionally be used in such mode, it can be retained for isolation purposes only as illustrated and described in connection with FIG. 1. In one form, the control signal 44 is of a periodic square waveform type that correspondingly switches operation of resonator 50 between two cavity modes via circuitry 40 and laser 22.
Referring to the schematic representation of
The light along path 122 a is provided to excite optical resonator 150 of system 120. Resonator 150 includes enclosure 151, beam coupling mirror 128, mirror 152, mirror 154, and adjustment device 60. Enclosure 151 defines optical cavity 156 in which coupling mirror 128, mirror 152, and mirror 154 are disposed. Incident light from path 122 a is split into two different beams by coupling mirror 128. One of these beams is directed into the optical cavity ring comprising coupling mirror 128 itself, mirror 154 and mirror 152 to define an optical mode within the ring. The other beam is deflected directly on to sensor 170, which is comprised of combined light emanating from the cavity mode 158 to produce a heterodyne signal to provide signals desired for control of the laser via pathways 176 and 148, and the ringdown signal via pathway 174. This arrangement facilitates development of a circulating optical field designated by reference numeral 158 in FIG. 2.
Mirror 152 and coupling mirror 128 each have a generally planar reflecting surface, while mirror 154 is of a concave, spherical type aligned relative to mirror 152 and coupling mirror 128 to provide the optical ring path. Mirror 154 is engaged by adjustment device 60 which is coupled to signal source 62. Device 60 and source 62 can operate as described in connection with like reference numerals of
Sensor 170 of system 120 detects intensity of light from resonator 150 via path 122 b to provide a corresponding sensor signal. Sensor 170 can be of any type, such as those described in connection with sensors 30 and 70 of system 20. The signal from sensor 170 is provided along pathway 174 to evaluation device 72 of system 120. Evaluation device 72 includes display 74 as were previously described in connection with system 20. The sensor signal is also provided along pathway 176 to stabilization circuitry 140 of system 120. Stabilization circuitry 140 receives the sensor signal through input 140 a which is used as feedback to adjust the output of source 122 via pathway 148. Accordingly, stabilization circuitry 140 can define or include a servo device or circuit suitable to operate a laser form of source 122 via pathway 148 as described in connection with laser 22 and circuitry 40 of system 20.
Stabilization circuitry 140 operates to lock the modulation frequency of output light from source 122 at a value desired to establish/sustain a resonating optical field 158. This feedback loop is schematically designated by reference numeral F2 in FIG. 2. Control source 44 provides a frequency control signal to circuitry 140 via input 140 b. Circuitry 140 is responsive to change modulation frequency of light output by source 122 via a source control signal along pathway 148, such that a given resonance of resonator 150 is halted. Alternatively or additionally, stabilization circuitry 140 can be arranged to respond to the control signal from source 44 to switch between one or more different resonant modes of resonator 150. In one form including a servo device, the frequency control signal from source 44 can be provided to a feed forward type of arrangement FF2 associated with the servo.
When a resonance mode is discontinued or switched, the sensor signal to device 72 via pathway 174 can be utilized to comparatively evaluate decay or ringdown in the manner previously described. It should be appreciated that system 120 does not include a Faraday isolator or AOM, although such additional devices might be utilized in other embodiments. Nevertheless, in many embodiments it is frequently desirable to exclude isolators, AOMs, and the like, which is made possible by the present invention. By using a ring cavity such as that defined by resonator 150, reduces the returned signal along pathway 122 a can be reduced to backscatter and reflection from sensor 170 back through the ring, which are often manageable in desired implementations. Allowing removal of Faraday isolators and AOMs, which in Long Wavelength InfraRed (LWIR) are typically bulky and inefficient, can be particularly desirable. System 120 further includes analyte source 80 which can be used to selectively introduce an analyte into optical cavity 156 for analysis in the manner previously described.
It should be appreciated that two or more of source 122, resonator 150, device 60, source 62, sensor 170, device 72, source 44, and circuitry 140 can integrated together into a common unit along with any operatively connecting paths or pathways. Source 122, device 72, source 62, source 44, sensor 170, or circuitry 140 can include one or more connections in common with one or more computing and/or control systems, power supplies, or the like. Although not shown, it should be appreciated that equipment to regulate one or more environmental characteristics of any or all the optical and/or electrical components of system 120 can be utilized; where such characteristics include, but are not limited to temperature, humidity, and pressure. Pathways 174 and 176 are typically of an electrical conducting type to transmit corresponding electronic signals of a varying voltage and/or current variety.
The present invention will be further described with reference to the following specific example. It will nevertheless be understood that this example is merely illustrative and is not intended to restrict or otherwise limit the scope of the present invention.
Further, any theory, mechanism of operation, proof, or finding stated herein is meant to further enhance understanding of the present invention, and is not intended to limit the present invention in any way to such theory, mechanism of operation, proof, or finding. While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only selected embodiments have been shown and described and that all equivalents, changes, and modifications that come within the spirit of the inventions as defined herein or by the following claims are desired to be protected.
Patent Citations
Non-Patent Citations
Referenced by
Legal Events
Original Image


text:
Partial Characterization of the Potential Biodegrading Ability of Xylaria sp. on Natural Rubber, Chicken Feathers, and Polystyrene A Thesis Proposal In Partial Fulfillment of the Requirements For Biology 200: Undergraduate Thesis AY 2008-2009 Dayao, Janine Erica P. Egloso, Mary Bernadette V. August 1, 2008 INTRODUCTION Background of the Study Pollution is an inevitable problem due to population growth, urbanization and the increased demand for manufactured products in the local and export markets. Industrialization has resulted to the generation of wastes of various forms that pose serious risks to the environment and public health, thus, requiring an efficient waste regulatory management. At the advent of technology, pollution has indeed taken its toll on nature, making people harvest and manufacture products that would take eons to decay and rot at the very least. Everywhere, a plethora of biodegradable and non biodegradable wastes can be seen. And, indeed it's high time that people revert back to natural processes that could help solve the burgeoning problem of waste disposal since all the artificial methods that require today's technology could contribute to the pollution that the planet's experiencing now. One such natural process that could solve the problem, or in a way even just alleviate such waste pile-up, is biodegradation. The country's population growth rate, which is one of the highest in the world (Mangahas, 2006), places serious strains on the economy. In 2005, the population was 82.8 million, of which 51.8 million or 63% lived in urban areas. Metro Manila is the most densely populated urban area with 10.7 million (Mangahas, 2006). Over the past 3 decades, the country's economy slid behind many Asian economies. Gross domestic product (GDP) grew at an average of only 3%, compared with 8% in the People's Republic of China (PRC); 6% in the Republic of Korea, Singapore, Malaysia, and Thailand; and 5% in Indonesia over the last 30 years (Wallace Report 2004 as cited by Mangahas, 2006). Urbanization, decline in the economy and further population growth lead to the even higher generation of wastes that has not been managed properly and safely (DENR, 2004). Presidential Decree (PD) 1152, or "the Philippine Environmental Code," provides the basis for an integrated waste management regulation starting from waste source to methods of disposal. PD1152 has further mandated specific guidelines to manage municipal wastes (solid and liquid), sanitary landfills and incineration, and disposal sites in the Philippines. Apart from the basic policies of PD1152, waste management must also comply with the requirements and implementing regulations of other specific environmental laws, such as PD984 (Pollution Control Law), PD1586 (Environmental Impact Assessment System Law), RA8749 (Clean Air Act) and RA9003 (Ecological Solid Waste Management Act) (DENR, 2004). A study by Clutario and Cuevas (2001) showed that Xylaria sp. can utilize polyethylene plastic strips as an alternative carbon source. The fungus grew optimally at 250C on a mineral medium of pH5 containing 0.5% glucose and polyethylene plastic strips as co-carbon source. A mucilaginous sheath was produced by the fungus to help its mycelial growth adhere to the surfaces and edges of the plastic strips. After 50 days of incubation, the strips became embedded in the mycelial growth. Visible damage on the surface structure of the plastic strips was observed using scanning electron microscopy (SEM). Striations and tearing were present due to the active burrowing of Xylaria hyphae on the polyethylene material. This shows that Xylaria sp. has indeed a potential in degrading synthetic wastes like plastics which are difficult to decompose. This proposed study aims to test the potential use of Xylaria sp. and its mutants as a natural biodegrading agent in biodegrading other rampant wastes such as natural rubber, polystyrene and chicken feathers. Objectives The proposed study aims to determine the biodegrading capacity of Xylaria sp. wild type and its mutants. The specific objectives are as follows: 1. to determine if Xylaria sp. mutants and wild type can assimilate natural rubber as a carbon source 2. to determine if Xylaria sp. mutants and wild type can assimilate chicken feathers as a carbon and nitrogen source 3. to determine if Xylaria sp. mutants and wild type can assimilate polystyrene as a carbon source 4. to compare the biodegrading ability of the wild type to each mutant to find which strain is most appropriate for each type of waste Significance of the Study Findings of this study might be utilized in the development of Xylaria sp. as a good biodegrading agent in reducing durable wastes such as plastics and others, as well as in optimizing fungal technologies. This study may also provide a way or ways in the discovery of other important characteristics of Xylaria sp. and its mutants, which may be used in other applications and scientific investigations. The discovery of other sources of biodegradation agents and their potential bioactive natural products is of paramount importance, especially nowadays that people should mostly concern about their waste disposal methods, and also to assure a good source of more accessible ways, through research, in approaching the reduction of pollution that are safe and can possibly boost the Philippine fungal industry in the world market. Scope and Limitations The experiment will serve as a source of preliminary information on the potential of Xylaria sp. to degrade chicken feathers, polystyrene and natural rubber. Other pollutants with similar biochemical structure to the aforementioned pollutants will not be included in the experiment. For the methodology, the Xylaria sp. that will be used will only come from the stock culture of UP Los Baños Biotech Institute. Culture media and reagents will be provided by BIOTECH. Experimentation will be done both in the Microbiology thesis room of the UP Manila, College of Arts and Sciences and in the Antibiotic Laboratory in BIOTECH. Isolation and purification of active components (i.e. enzymes) responsible for the probable degradation of chicken feathers, polystyrene and natural rubber will not be performed. Observation of colonization through scanning electron microscopy (SEM) will be carried out in BIOTECH. Only the crude weight percent difference of the colonization of the wastes will be recorded. The runs will only be done twice due to logistic matters and unavailability of equipments. Moreover, the incubation time for the degradation process of Xylaria sp. strains will only be limited to 30 days. In terms of data analysis, this experiment will only focus in analyzing the degradation potential of Xylaria sp. strains on Natural rubber, Chicken Feathers and Polystyrene. And also, it will be concerned whether the degradation potential of the Mutants is significantly different from the Wild type and so as to determine the more appropriate strain to use. REVIEW OF RELATED LITERATURE BIODEGRADATION Biodegradation is the breakdown of natural substances through the action of enzymes secreted by organisms such as microbes and fungi. Only waste materials made up of natural polymers can be degraded by microbes and fungi. Biodegradation works in such a manner that the organisms involved utilize, or more appropriately, metabolize these wastes as sources of nutrients such as carbon or nitrogen. (Tortora et al., 2005). In many cases, conditions are not favorable enough to promote spontaneous biodegradation or natural attenuation. Whenever there is insufficient quantity of naturally biodegrading organisms, there is a further need to add nutrients or other suitable organisms aside from those present already, for improved biodegradation to occur. The general objective of biodegradation is to discern the speed of unaided biodegradation before catalysts may even be added, and then strengthen spontaneous biodegradation only if this is not fast enough to remove the contaminant's concentration in the environment at which it may cause health risks to nearby inhabitants such as people, animals and plants (European Federation of Biotechnology, 1999). MICROORGANISMS USED IN BIODEGRADATION Through time, scientific experiments have already proven the ability of some microorganisms to biodegrade pollutants such polyethylene, polystyrene, rubber, chicken feathers and other types of wastes. Organisms such as bacteria and fungi have proven themselves to possess the capacity to biodegrade pollutants. Bacteria such as Brevibaccillus borstelensis is one. Plastics in the form of polyethylene are known to be degraded by the thermophilic bacterium Brevibaccillus borstelensis 707 which was isolated from soil. (Hadad et al,2005). Another study by Orr et al. (2004) featured the Rhodococcous ruber C208 as an effective polyethylene-degrading organism. In addition to this, this strain has been proven to degrade polystyrene ( Mor & Sivan, 20080. Yet originally, Rhodococcus rubber is a known rubber-degrading organism, according to the review of Rose and Steinbuchel (2005). Other known rubber-degrading microorganisms are Gordonia sp., Streptomyces sp., and Xanthomonas sp. strain 357. Moreover, a study of Barraat et al. (2003) investigated the relationship of the water-holding capacity of the soil and polyurethane degradation and found out that the following organisms could biodegrade polyurethane: Nectria gliocladioides (five strains), Penicillium ochrochloron (one strain) and Geomyces pannorum (seven strains). On chicken feathers, various strains had already been isolated too. In a study conducted by Cao et al. (2008), the fungus Trichoderma atroviride completely degraded the chicken feathers. This strain was actually isolated from a decaying feather. Another organism proven to degrade chicken feather is Bacillus subtilis mutant strain as investigated by the study of Cheng chang et al. (2003). The list of microorganisms that could be used in biodegrdation goes on for there are still more species that could degrade pollutants. And in fact, in the Philippines a fungus has been isolated and proven to degrade polyethylene (Cuevas & Manaligod, 1997). Xylaria sp. AS A POTENTIAL AGENT FOR BIODEGRADATION Xylaria sp. was discovered by Cuevas and Manaligod (1997), growing on a sando plastic bag, buried in forest soil and litter in the lowland secondary forest of Mt. Makiling, Laguna. The fungus comprised of sterile melanin pigmented mycelia and was reported as ascomycete sterile dark mycelia (ASDM). Cultural studies have designated it under Class Ascomycetes, Order Xylariales, Genus Xylaria (Clutario and Cuevas, 2001). A previous study by Clutario and Cuevas (2001) proved that Xylaria sp. can utilize polyethylene plastic strips as an alternative carbon source, thereby degrading them into usable forms for self-sustenance. Through the use of scanning electron microscopy, the proponents of the said study observed visible damages of the surface structure of the plastic strips. There were tearing and striations caused by active burrowing of Xylaria hyphae on the polyethylene material. Plastic is an extremely versatile synthetic material made of high molecular weight, semi-crystalline polymer prepared from ethylene through the cracking of crude oil, light petroleum and natural gas. For plastic bags alone, it is estimated that some 430,000 gallons of oil are needed to produce 100 million pieces of these omnipresent consumer items on the planet (Knapczyk and Simon, 1992; EcoWaste Coalition, 2008). Figure 1. Xylaria in its natural habitat. Figure 2. Xylaria fruiting body surrounded by flask-shaped structures called peritheca. Figure 3. Cross section of Xylaria stroma. Xylaria is one of the most commonly encountered groups of ascomycetes with most of its members being stromatic, peritheciate, with an iodine-positive ascus apical ring, and with one-celled, dark ascospores on which agermination slit can be found. Most are inhabitants of wood, seeds, fruits, or leaves of angiosperms. Some are associated with insect nests. Most decay wood and many are plant pathogens. Many are endophytes. They are commonly found throughout the temperate and tropical regions of the world. The Xylaria sp. can be distributed above, around, and beneath perithecia. It forms a unipartite stromatal layer, with a superficial or erumpent surface level. The interior of its stromata is essentially homogeneous. Conidium-bearing discs, potassium hydroxide pigments and orange granules surrounding the perithecia are absent (Rogers et al., 2002). They are mostly multiperitheciate in ascomatal number per stroma, ascomatal ostioles and ascal apical rings: are present, and the ascospore cell number is one-celled. Teleomorph and anamorph are produced on the same stromata in most species, with their anamorphs: Geniculosporium-like. Some Xylaria sp. species exist as endophytes, and have mutualistic associations with plants. The fungus secrete toxins to protect the plant from herbivory from other insects or animals, while the fungus in return feeds on the host's tissues for nutrition, and its mycelia are scattered through seed dispersal. Xylariaceae endophytes are hypothesized to be quiescent colonizers that decompose lignin and cellulose when a plant dies. Nonetheless there are also some xylariaceous fungi that only exist as endophytes. No obvious benefit to living host plants has been documented for Xylariaceae (Petrini et al., 1995; Whalley, 1996; Rogers, 2000; Davis, et al., 2003) A review of empirical studies on antagonistic interactions between endophytes and grazers, insects and microbial pathogens summarizes five general properties of endophyte mutualism: (1) the endophyte is ubiquitous in a given host, geographically widespread, and causes minimal disease symptoms in the host plant; (2) vertical transmission or efficient horizontal transmission of the fungus occurs; (3) the fungus grows throughout host tissue, or, if confined to a particular organ, a high proportion of such organs are infected; (4) the fungus produces secondary metabolites likely to be antibiotic or toxic; and (5) the endophyte is taxonomically related to known herbivore or pathogen antagonists (Carroll, 1988; Davis, et al., 2003). SOLID WASTE IN THE PHILIPPINES Filipinos generate around 0.3 to 0.7 kilograms of garbage daily per person depending on income levels (World Bank, 2001). Metro Manila produces about 8,000 tons of solid waste each day and is expected to reach 13,300 tons each day in 2014 (Baroña, 2004). The National Capital Region produces the highest amount of wastes, about 23% of the country's waste generation (Anden and Rebolledo, 2003). Based on studies (2001) made by the National Solid Waste Management Commission Secretariat based at the Environmental Management Bureau (EMB), it is estimated that in Metro Manila, the per capita waste production daily is 0.5 kg. Thus, every person living in the metropolis generates half a kilo of waste a day. With an estimated population of 10.5 million, total waste generated in Metro Manila alone could run up to 5,250 metric tons per day or 162,750 metric tons per month or 1.95 million metric tons per year. Based on another EMB study (2001) regarding the disposal of daily wastes, only about 73% of the 5,250 metric tons of waste generated daily are collected by dump trucks hired by local government units. The remaining 27% of daily wastes, or about 1,417.5 metric tons, end up in canals, vacant spaces, street corners, market places, rivers and other places. According to a survey conducted by the EcoWaste Coalition and Greenpeace Southeast Asia in 2006, synthetic plastics comprise 76% of the floating trash in Manila Bay, out of which 51% are plastic bags, 19% are sachets and junk food wrappers, 5% are styrofoams and 1% is hard plastics. The rest were rubber (10%) and biodegradable discards (13%) (EcoWaste Coalition, 2008). Polystyrene Polystyrene, an aromatic polymer, is synthesized from the aromatic monomer styrene which comes from petroleum products. It is a thermoplastic substance that could be solid in room temperature or liquid when melted. One of the most common forms and uses of polystyrene is the EPS which stands for Expanded Polystyrene. The industry manufactures such product by mixing polystyrene with blowing agents in the form of carbon dioxide and pentane which comprises 5%-10% of its composition. The EPS is also called foamed polystyrene and it is said to be 30 times lighter than regular polystyrene. This substance is popularly used in the form of beverage cups and insulating materials. (Friend, 2005). The basic unit of polystyrene which is styrene, which is a known neurotoxin and animal carcinogen, is considered very harmful to human health. In fact, it inflicts neurological and hematological disorder especially to factory workers. EPS food packaging is the one accountable for the leaking out of styrene. Styrene leak or leech is triggered when acids from our juices when placed in such EPS cups and when food with Vitamin A content is placed inside a microwave leading the styrene to accumulate in our system. (Californians Against Waste, 2008). Polystyrene is in high demand. It is the most used and utilized thermoplastic in the industry due to its durability. But it is not biodegradable. (Mor and Sivan, 2008). According to the Californians Against Waste (2008), it is very difficult to recycle due to its light weight property, which accounts for why it's expensive to recycle. Imagine just recycling a ton of polystyrene, needs a budget of $3000. Hence, it has a negative scrap-value. More so, it's due to this light weight property that they find polystyrene hard to transport since polystyrene is advised to be always kept food-free and uncontaminated when recycled. The build-up of polystyrene in landfills, as reported by CAW (2008), will contribute to plastic marine debris, since even when it is disposed of properly it is carried by natural agents such as wind or other forces to the ocean. As manifested, there is an excess of it in the environment and it is a major pollutant. (Mor and Sivan, 2008). For almost three decades ago, polystyrene was first ban due to the utilization CFC material for its generation. In fact there was a hype heralding that it is recyclable. After some time the companies that invested for its recycling process disappeared. This move confirms that, indeed, recycling polystyrene is not an easy thing to do. Now, the problem is back and the attention of scientists is focused on the recycling of disposable foamed polystyrene. But recycling it would cost much in terms of energy, waste and management point of view. (Californians Against Waste, 2008). A way of solving such impending problem, is through biodegradation (Mor and Sivan, 2008; Singh and Sharma, 2007). Biodegradation has been manifested in a number of studies already. And some of the studies will be named here. A study by Mor and Sivan (2008), dealt with the monitoring of biofilm formation of the microbe Rhodococcus sp. strain C208 on polystyrene. Their aim was to observe the kinetics of biofilm formation and of whether polystyrene would be degraded. They used two methods in quantifying the biofilm biomas: modified crystal violet staining and observation of the protein content of the biofilm. The C208 strain was cultured in a flask containing polystyrene flakes with the addition of mineral oil (0.0055% w/v), which induced more biofilm buil-up. The study concluded that after an extension of 8th weeks of incubation, loss of 0.8% (gravimetric weight loss) of polystyrene weight was found. From this, Mor and Sivan (2008) regarded C208 to demonstrate a high affinity towards polystyrene through biofilm formation which lead to it's degradation. The C208 strain is a biofilm-producing actinomycete that has first colonized and degraded polyethylene (Orr et al., 2004). There were studies that tested the possibility of whether copolymerizing polystyrene with other substance could make it more degradable and susceptible to microbial attack. In 1992, a study by Milstein at el. (1992), focused on the biodegradation of a lignin- polystyrene copolymer. The white rot basidiomycete was used to degrade such lignin- polystyrene complex copolymer. Such fungi released enzyme that oxidized lignin and demonstrated the degradation through weight loss, UV spectrophotometric analysis and deterioration of surface of the plastic substance as seen under the SEM. A similar study by Singh and Sharma (2007) demonstrated through the process of graft copolymerization that polystyrene must be modified with natural polymers and hydrophilic monomers so as to enhance its degrading ability and so as to render polystyrene waste useful in diminishing metal ion pollution in water and. According to the mentioned study, the degrading rate of polystyrene increased to 37% after subjecting it to soil burial method for 160 days. Furthermore, the study of Motta et al. (2007), explored the degradation of oxidized polystyrene using the fungi Curvularia sp. After about nine weeks of incubation, microscopic examination revealed that hyphae had grown on the polystyrene. The colonization of the fungi and it's adhesion to the surface of the substance, according to Mota et al., is a crucial step towards polymer biodegradation. As demonstrated, colonization is needed in determining whether a particular microbe or organism is a potential biodegrading agent. (Mota et al., 2007) The growth of the microbes on the surface of the polystyrene is a step that would lead to its degradation. Further visual confirmation of deterioration of surface area is done by using the scanning electron microscope. (Mor and Sivan, 2008; Mota et al., 2007). Natural Rubber Natural rubber (NR) is made from the latex of the Hevea brasiliensis also known as the rubber tree. It is mainly composed of cis-1,4 polyisoprene which has a molecular mass of about 106 Da. This could also be chemically synthesized and produce the substance known as Isoprene Rubber (IR). (Linos et. al, 2000). Since 1914, natural rubber has been a classic subject of biodegradation studies. (Rose and Steinbuchel, 2005). This is due to the high rate of its yearly manufacture which is several million tons, as mentioned in the study of Bereeka (2006), and its slow rate of natural degradation as reviewed by Rose and Steinbechul (2005). In fact, a number of studies abound concerning its degradation. And it has been learned that both bacteria and fungi can participate in such process. Throughout all the investigations and experimentations done, two categories of rubber-degrading microbes according mainly on growth characteristics have been established. Based on a review of Rose and Steinbuchel (2005), which recapped the aforementioned groups, the microbes that can degrade rubber can be categorized as clear zone-forming around their colonies and non-halo forming whenever isolated and cultured in latex overlay plate, which is made by overlaying a layer of latex agar medium on a basal salt medium agar. The former category was identified to mainly consist of actinomycetes species. They are said to biodegrade or metabolize rubber by secreting enzymes and other substances and also they are dubbed to be slow degraders since they rarely show an abundant cell mass when grown on natural rubber directly. On the other hand, members of the second group do not form halos on latex overlay plates. They, unlike the first group, grow more when directly grown on natural rubber. In a way, their growth on rubber could be described in an adhesive manner. The second group is said to demonstrate a relatively stronger growth on rubber. Species comprising this category are the Corynebacterium-Nocardia-Mycobacterium group. They consist of the Gordonia polyisoprenivorans strains VH2 and Y2K, G. westfalica strain Kb1, and Mycobacterium fortuitum strain NF4. As demonstrated by a particular study by Linos et al. (2000), the mechanisms that the microbes undergo when biodegrading is colonization, biofilm formation and aldehyde group formation after cultivating it on the surface of latex gloves. Such is revealed after undergoing the Schiff reagent's test. This is further examined under a scanning electron microscope. In their methodology they have indicated that the preliminary screening method to be used in finding potential rubber-degrading bacteria is by growing such bacteria or microbe on the latex overlay or by latex film on the mineral agar plates. Growth and colonization of the microbe in this medium would indicate its utilization of rubber as its sole carbon source; hence, making it as a potential rubber-degrader. Chicken Feathers In the US alone, 2 billion pounds of chicken feathers are produced by the poultry industry (Comis, 2008). Chicken feathers, by nature, are made up of over 90% protein (Cheng-cheng et al., 2008). And this protein is none other than keratin. It's actually the most abundant protein. It is not easily degraded due to its tightly packed structural arrangement which is in the form of alpha keratin or beta keratin. The key to its stability lies on the cross-linking by disulfide bonds, hydrophobic interactions, and hydrogen bonds. Such stability renders keratin water-insolube and non-degradable by the enzymes papain, trypsin and pepsin. (Gradisar et al., 2005). In a study conducted by Onifade et al., 1998 and Goushterova et al., 2005, as cited in the journal of Cheng-Cheng et al., 2008, the build-up of chicken feathers in the environment and landfills would only result to future pollution problems and protein wastage. More so, its accumulation could serve as a breeding ground for a variety of harmful pathogens (Singh, 2004). Considering that chicken feathers have a high protein content it could also be used as an animal feed, but first its protein must be degraded (Tapia & Contiero, 2008). Yet this is said to need so much water and energy (Frazer, 2004). Old methods of degrading the chicken feathers such as alkali hydrolysis and steam pressure cooking are no longer advisable. They cause so much energy wastage and they unfortunately destroy the configuration of proteins. (Cheng-cheng et al., 2008). Incineration is also a method used in degrading such waste but it causes so much energy loss and carbon dioxide build-up in the environment. Other methods of disposal are landfilling, burning, natural gas production and treatment for animal feed. But subjecting it to burning and land filing costs a lot and it contributes air, soil and water contamination. (Joshi et al., 2007). A wiser suggestion or approach would be the use of microbes in degrading these chicken feathers. (Cheng-cheng et al., 2008). Such approach is said to an economical and environment-friendly alternative (Joshi et al., 2007). Experiments that tested on the degradation of chicken have already been done. In fact, studies have already proven that keratinolytic microbes such as Bacillus (Maczinger et al., 2003; Rodziewicz and Wojciech, 2008; Joshi et al.,2007) , fungi ( Gradisar et al., 2005) and actinomycetes (Goushterova et al., 2005). The enzymes that perform keratin degradation are called keratinase, which could degrade feathers and make it available for its use as animal feed, fertilizer and natural gas. The enzymes are said to degrade the beta-keratin component and the main idea behind such biodegradation is that the microbes use the feather as their carbon, nitrogen, sulfur and energy for their nourishment. (Joshi et al.,2007 ; Manczinger et al., 2003). Keratinases isolated from microbes have various economic uses. Aside from its feather degrading capacity, it could be used in the leather industry as an agent in dehairing leather. Its by-product, the feather hydrolysate, could also be used as animal feed additive. (Joshi et al., 2007). Furthermore, potentially, the said hydolysate could be used in the generation of organic fertilizer, edible films and amino acids which are considered rare, as cited by Brandelli in the journal of Joshi et al.( 2007). In terms of experimental procedures, various methods are used in determining the keratinolytic ability, which means it could produce keratinase and hence degrade chicken feather, of microbes. A particular study by Tapia and Contiero (2008), used a feather meal agar, wherein the feather served as the source of carbon, nitrogen, sulfur and energy, in cultivating the isolated microbe Streptomyces. The growth, which occurred on the 10 th day of incubation, through colony formation of the microbe indicated that it utilized the feather as a source of its nutrients. After which, its keratinolytic activity was tested using a modified keratin azure protocol. Another study by Maczinger et al. (2003) focused on the isolation of a microbe from the poultry waste that could degrade feathers. During the preliminary elimination, they cultured the different population of bacteria found in a partially degraded feather in a basal medium with sterilized feathers serving as its source of carbon, nitrogen and sulfur. It was then rotated in an orbital shaker for 10 days. After 4 days, one flask which showed a visual degradation of the feather. A dilution series was made afterwards so as to isolate and culture the bacteria that just degraded the feather. The strain was identified as Bacillus lichenformis strain K-508. And the confirmation of the keratinolytic activity was done by using the azokeratin as a substrate assay. Isolation of a new microbial organism that could degrade chicken feather will help in the degradation of the chicken feathers which is now becoming a burden in the society both internationally and locally. The microbe could potentially provide the keratinase that could be used in compost technology (Maczinger et al., 2003) or in the conversion of feather to feedstock meal additives (Tapia and Contiero, 2008). METHODOLOGY I. Research Design The research design to be used in the study is the Randomized Complete Block Design (RCBD). The experiment will consist of two trials with three replicates per treatment. The experimentation process will be conducted in UP Los Banos Institute of Biotechnology. II. Experimentation A. Preparation of Inoculum The stock culture of Xylaria sp. and its four albino mutant strains will be obtained from UPLB Biotech. Xylaria sp. will be isolated by culturing it in a Potato Dextrose Agar (PDA) medium. The pH will be adjusted to pH 5 and it will be incubated at 25˚C. After 2-3 days, the fungi will be transferred into the test media. B. Preparation of Pollutants A. Polystyrene 1x1 cm strips will be cut from clean polystyrene food containers such as coffee foam cups. And four strips per replicate of each treatment will be used. B. Chicken feathers Fresh feathers from Gallus sp. will be obtained from a nearby market place where chickens are butchered and sold. The feathers will be sterilized by placing it inside a SM plastic bag and autoclaved for 20 minutes at 15psi. One feather per replicate of treatment will be used. C. Rubber Obtain rubber latex gloves size 5 from Mercury Drugstore. Cut the gloves into strips of the same sizes, approximate area to be about 2x2. Use 2 strips per replicate of each treatment. C. Biodegradation Proper using Culture Method Two sets of flasks will be prepared containing 50 ml Mineral Medium each, in triplicate. 0.5% glucose will be added in set A and B. The pH will be adjusted to pH 5 by adding small amounts of either 0.1M NaOH or 0.1M HCl. Then the microorganism will be added using the wire loop inoculation method. The addition of pollutant in set B only will follow right after. The flasks will be subjected in a shaker for four hours to homogenize the medium. The culture will be observed for some time then when all the glucose has been used up and the fungi have grown into a considerable mass as examined visually, another MM + 0.5% glucose will be added in set A only, leaving the set B flasks to utilize the solid pollutants as the sole carbon source. The extent of colonization will be carefully examined every day until rate of colony growth can be predicted (growth in mm/day). But if otherwise, the addition the MMG (mineral medium+0.5%glucose) to both sets of flasks will be continued until the fungi have grown and thrived. Incubate for30 days, with the flasks in a room with more or less 250C in temperature.The solid pollutants will then be removed from the culture medium and examined under a scanning electron microscope (SEM). Note: * this step is intended for each mutant and for the wild type. Since we have 4 mutant strains and a wild type, this step will be repeated five times multiplied with the number of pollutants to be used. D. Determination of Amount of Degradation through Colonization After 30 days, the remaining pollutant will be weighed in grams. This measurement will be recorded as the final weight. The percent weight loss of pollutant will be determined using the formula: % weight loss = (initial weight – final weight) Initial weight Statistical Analysis The designed that will be used for this study is Random Complete Block Design (RCBD). The blocks will be the Xylaria sp. and the mutants while the treatment will be the three pollutants namely natural rubber, chicken feather and polystyrene. Your study design is RCBD so your analysis should therefore be ANOVA for RCBD (Which you can easily analyze using Microsoft excel….and no need to put the software to be used in your proposal). Then you should put an ANOVA table without data after your dummy tables. Xylaria sp and its mutants will serve as the blocks since you will be randomly distributing the pollutants to them. Your DATA/DUMMY table #2 (since okay na yung first dummy table ninyo na kasama yung replicates) will then look like this (please write an appropriate title above it): Xylaria Polystyrene Natural Chicken strain Rubber Feathers Wild- type Mutant1 Mutant2 Mutant3 Mutant4 Hypothesis (Hypotheses for the blocksF for rows) Ho1: There is no significant difference in the biodegrading ability of the different Xylaria sp. strains on the pollutants. Ha1: There is a significant difference in the biodegrading ability of the different Xylaria sp. strains on the pollutants. (Hypotheses for the pollutantsF for columns) Ho2: There is no significant difference in the degree of biodegradation of polystyrene, natural rubber & chicken feathers due to Xylaria sp. Ha2: There is a significant difference in the degree of biodegradation of polystyrene, natural rubber & chicken feathers due to Xylaria sp. Dummy Tables **Table 1 will be use for each pollutant and such table would be used for the two runs that will be conducted. Table 1. Percent Weight Loss of the (insert pollutant name here) due to Xylaria sp. strains Replicate 1 Replicate 2 Replicate 3 Mean Wild type Mutant 1 Mutant 2 Mutant 3 Mutant 4 Table 2. Mean Values of the Percent Weight Loss of Polystyrene, Natural Rubber and Chicken Feathers due to degradation of Xylaria sp. strains Xylaria strain Polystyrene Natural Chicken Rubber Feathers Wild-type Mutant1 Mutant2 Mutant3 Mutant4 Table 3. ANOVA for Randomized Complete Block Design of the Potential Biodegrading Ability of Xylaria sp. Strains on Chicken Feathers, Natural Rubber and Polystyrene Source of Variation SS df MS F P-value F crit Rows (Xylaria strain) Columns (pollutant) Error α = 0.05 LITERATURE CITED Anden, C. M. N. and Rebolledo, A. B. J. (2003) ASrIA Reports - SRI In Asian Emerging Markets: Philippines.www.asria.org/publications/lib/country/philippines_appendix.pdf [retrieved 2008, June 13] Baroña, M. L. J., 2004. Fungi: A Solution to Manila's Plastic Woes. Department of Agriculture. Bureau of Agricultural Research. Vol. 5 No. 8 Bereeka, M. (2006). Colonization and Microbial Degradation of Polyisoprene Rubber by Nocardioform Actinomycete Nocardia sp. strain-MBR. Biotechnology 5(3): 234- 239 Cao, L.; Tan, H.; Liu, Y.; Xue, X. and Zhou S. (2008). Characterization of a New Keratinolytic Trichoderma atroviride strain F6 That Completely Degrades Native Chicken Feather. Letters in Applied Microbiology 46 (3), 389–394 Cheng-gang, C.; Bing-gan, L. and Xiao-dong, Z. (2008). Keratinase Production and Keratin Degradation by a Mutant Strain of Bacillus subtilis. Journal of Zhejiang University Science Vol. 9(1): 60–67. Clutario, M. T. P. and Cuevas, V. C. (2001). Colonization of Plastic by Xylaria sp. Philippine Journal of Science 130 (2): 89 – 95. Davis, E. C., Franklin, J. B., Shaw, A. J. and Vilgalys, R. (2003). Endophytic Xylaria (Xylariaceae) Among Liverworts and Angiosperms: Phylogenetics, Distribution, and Symbiosis. American Journal of Botany 90(11): 1661–1667. DENR. 2004. Hazardous Waste Management Procedural Manual Title III of DAO 92-29 http://www.env.go.jp/en/recycle/asian_net/reports/secondyearwork/philippines.pdf [retrieved 2008 June 21]. Environmental Management Bureau-DENR. Managing our Solid Waste: An Overview of the Ecological Solid Waste Management Act. http://www.emb.gov.ph/eeid/ESWM.htm [retrieved 2008 June 21] Duane, Friend (2005). The Pros and Cons of Styrofoam. Land and Water Conserving Natural Resources in Illinois no.5 Environmental Biotechnology: Bioremediation, Prevention, Detection and Monitoring, Genetic Engineering. 1999. Briefing Paper 4. 2nd ed. EFB Task Group on Public Perceptions of Biotechnology Environmental_biotechnology_English.pdf [retrieved 2008, June 4]. Fast Food Waste Threatens our Marine Environment, Drags Down Diversion Rates. Californians Against Waste Organization. [retrieved: 2008, July 1]. http://www.cawrecycles.org/issues/fast_food Gradišar, H.; Friedrich, J.;Križaj, I.; and Jerala, R. (2005). Similarities and Specificities of Fungal Keratinolytic Proteases: Comparison of Keratinases of Paecilomyces marquandii and Doratomyces microsporus to Some Known Proteases. Application of Environmental Biology Vol 71(7): 3420-3422 Gushterova, A.; Vasileva-Tonkova, E.; Dimova, E.; Nedkov, P. and Thomas Haertlé (2005). Keratinase Production by Newly Isolated Antarctic Actinomycete Strains. World Journal of Microbiology and Biotechnology Vol. 21 (6-7):831-834 Joshi, S.; Tejashwini, M.; Revati, N.; Sridevi, R. and Roma, D. (2007). Isolation, Identification and Characterization of a Feather Degrading Bacterium. International Journal of Poultry Science 6 (9): 689-693 Linos, A.; Berekaa, M.; Reichelt, R.; Keller, U.; Schmitt, J.; Flemming, H.; Kroppenstedt, R. and Steinbüchel, A. (2000). Biodegradation of cis-1,4-Polyisoprene Rubbers by Distinct Actinomycetes: Microbial Strategies and Detailed Surface Analysis. Applied Environmental Microbiology 66(4):1639-1645 Mangahas, J. Y. (2006). Urbanization and Sustainability in Asia: Case Studies of Good Practice: The Philippines. http://www.adb.org/Documents/Books/Urbanization- Sustainability/summary-booklet.pdf [retrieved 2008, June 21]. Manczinger L.; Rozs, M.; Va´gvo¨ lgyi, Cs.; and Kevei, F. (2003). Isolation and Characterization of a New Keratinolytic Bacillus licheniformis strain. World Journal of Microbiology and Biotechnology Vol. 19: 35–39 Milstein, O.; Gersonde, R.; Huttermann, A.; Chen, M. & Meister, J. (1992). Fungal Biodegradation of Lignopolystyrene Graft Copolymers. Applied Environmental Microbiology Vol 58(10):3225-3232 Mor, A. and Sivan, A. (2008). Biofilm Formation and Partial Biodegradation of Polystyrene by the Actinomycete Rhodococcus rubber :Biodegradation of Polystyrene. Biodegradation Journal Motta, O.; Proto, A.; De Carlo, F.; De Caro, F.; Santoro, E.; Brunetti, L. and Capunzo, M. (2007). Utilization of Chemically Oxidized Polystyrene as Co-Substrate by Filamentous Fungi. International Journal of Hygiene and Environmental Health Orr, I.; Hadar, Y. and Sivan, A. (2004). Colonization, biofilm formation and biodegradation of polyethylene by a strain of Rhodococcus rubber. Applied Microbial Technology Vol. 65(1):97-104 Polystyrene and Food Packging Waste (2008). Californians Against WasteOrganization.[retrieved:2008,July1].http://www.cawrecycles.org/issues/polysty rene_main Rodziewicz, A. and Wojciech, A.( 2008). Biodegradation of Feather Keratin by Bacillus cereus in Pure Cultue and Compost. Electronic Journal of Polish Agricultural Universities Vol. 11(2): 20. Rogers, J. D., Ju, Y. M., and Adams, M. J. (2002). The Genus Xylaria. http://mycology.sinica.edu.tw/Xylariaceae/information.asp?qrySectionName=Xylaria &qryIDString=x040. [retrieved: 2008,July 1]. Rose, K. and Steinbüchel, A. (2005). Biodegradation of Natural Rubber and Related Compounds: Recent Insights into a Hardly Understood Catabolic Capability of Microorganisms. Applied and Environmental Microbiology Vol. 71(6):2803-2812. Singh, C. (2004). Exocellular Proteases of Malbranchea gypsea and their Role in Keratin Deterioration. Mycopathologia Vol. 143(3):147-150. Singh, B. and Sharma, N. (2007). Optimized Synthesis and Characterization of Polystyrene Graft Copolymers and Preliminary Assessment of Their Biodegradability and Application In Water Pollution Alleviation Technologies. Polymer Degradation and Stability Vol. 92(5):876-885. Tapia, D. and Contiero, J. (2008). Production and Partial Characterization of Keratinase Produced by a Microorganism Isolated from Poultry Processing Plant Wastewater. African Journal of Biotechnology Vol. 7 (3): 296-300. The Myth of Polystyrene Takeout (2008). Californians Against Waste Organization. http://www.cawrecycles.org/issues/eps_recycling.html [retrieved: 2008,July 1]. The Story of Polystyrene Bans. Californians Against Waste Organization. http://www.cawrecycles.org/issues/epsban_summary [retrieved: 2008, July 1]. Tortora, G. J., Funke, B. R., and Case, C. L. (2005) Microbiology: An Introduction. Pearson Education South Asia Pte. Ltd. 23-25 First Lok Yang Road, Jurong, Singapore 629733. 8th ed. pp. 772 – 774. Tavanlar, M. A. T. and Lat, E. C. (2008). Partial Characterization of Mutants from a Plastic- degrading Black Fungus.
Pages to are hidden for
"Thesis_Proposal_Draft3"Please download to view full document


text:
View Poll Results: best heavens gate!
- Voters
- 72. You may not vote on this poll
Results 1 to 13 of 28
June 19th, 2006 #1Registered User
- Join Date
- Aug 2003
- Location
- Sarasota, FL
- Posts
- 3,223
- Thanks
- 0
- Thanked 17 Times in 9 Posts
E.O.W Round 26: Heavens Gate - The Big Vote!
E.O.W Round 25: VOTING THREAD
TOPIC: Cafe
Deadline For Voting: Monday 26th June
Please vote for your personal favourite artwork from this round. Please remember that your vote should reflect an equal weight of aesthetic impact, adherance to the brief, and idea development.
Your votes will be public.
Please help strengthen the activity by leaving criticism for the artist you vote for, and for any other artworks you can manage!
posting thread
"20 Years without war!" says the speaker: "This should also have played a role, that humanity can enter space for few bucks." Another voice answers. "Yah, you r right, today is a great day, the star of the first tourist-class spaceship will start in a few seconds!"
I looked from the monitor to the TV, a large spaceship which was designed in an oldschool style spitted spoke and the red lights began to blink. A countdown began.
So this is heavens gate, i thought giggling.
The last task for the dead souls wandering the earth is to find heavens gate. Upon entering the gate all knowledge and the purpose of life is acquired. In life ignorance is bliss but in death complete knowledge of the universe brings about the highest form of serenity.
To find yourself at the Barrow Gate means you have lived your life to the full and pleased the gods. Your reward awaits you.
ferak seg
After a cataclysmic event certainly caused by human behaviours, all the life seems to have left the city. But there is still shadows which are waiting to take their last path, grumbling their bitterness and judging their ow, mistakes. If you listen carefully you can hear in a last sad breathe: "if only, we had..."
Millions of souls make the pilgrimage to Heaven's Gate, Nevada. God opens the gates to heaven once a year and He brings the faithful with him to heaven. Upon entering the light, the blasphemers and unrepentant sinners are instantly vaporized.
The Seven Portals to the Seven Heavans.
In a mountain range that exists on the edge of the physical plane, where the spiritual touches the tangible universe, stand the gates to the heavans. Seven portals, each a doorway to the realms of the Gods, are said to be the beginning of the soul's final journey. All who wish to be one with the Highest must pass thru a portal, and each portal is meant for different types of beings. A human who is passing on, finding favor with the Ancient Ones, will pass thru "Semilode enlu Gatifee - The Portal of the Third". Seen here to the lower right, The Portal of the Third is decorated with a pattern representing The Prayer Rugs of the Watchers, who keep the portals safe and hidden from the eyes of the Fallen.
The Gachlican Monks have developed a way to induce portal expansion with highly focussed particle cannons. They've named this phenomena 'opening Heaven's gate', as it leads to an alternate dimension completely untouched by human and alien lifeforms. The monks now offer a tour service to likeminded people, enabling them to experience the wonders of this destination. The cross-dimensional shuttle is loaded, and for no longer than 10 hours the patrons pass through a summoned portal and dock in 'Heaven'. When the alotted time expires, the command centre will reopen the gate.
This seems to have negligible affect on the environment of both worlds, and strict guidelines have been set up to maintain this situation.
Following the road of burning embers to the land of fire, is the only path to The Gates of Heaven. This is a journey of the body and mind. where the weak will pray for an quick death but if you can endure the quest. The rewards are unimaginable.
A dig site in the syrian desert revealed an enormous monolith, made of unusual alloys. After months of research small areas of writing were deciphered to reveal that this was refered to heaven's gate by whoever constructed it. Further reading told of a connection between it and the cygnus x-1 black hole. It has been theorised that such dense material would be necessary in creating a stable shield against radiation types, that could be emitted from a black hole.
High on top of the hill lies pathway to heaven; where the winds will guide you to the heaven.
Gateway for soul filtration, pure souls travel high, dark souls travel low, your destination is predetermined, face the light and enjoy the ride.
Tom Garden
above the clouds, they found a mighty wall, which had a hole....to heaven
"Those sons of bitches, first they ravaged the earth with their greed for power. Then they found the last hole in the ground with anything decent to drink and built their towers on it. They even had the audacity to call the place Heaven.. "
"Lo, they do call to me, they bid me take my place among them, In the halls of Valhalla, where the brave may live forever". As the honored and noble warriors sail into the great sea, eventually they come to the a place where the waters are calm and they see a new beginning...
stewart one
When the humans have all but whiped themselves out, the gates of heaven will open, and the earth will once again be reclaimed by the armies of heaven who once ruled this very place.
The USI "Iru Loko" ist the most secure and most known prison of Stedtfeld Systems and is located on Iru II-A on an island, underground and most of the building under sea level. Here the most savage beast and the most dangarous beeings are kept, far away from the puplic society, the USI is the only building on the planet. Built from an alloy only known to some scientists who invented it, the only way to enter or exit is the tower that arises overground for about 100 metres. No prisoner or beast ever escaped, no one ever left dead and also because the tower is the only source of daylight it is called "The Heavens Gate" by prisoners and keepers.Sketch Book
Originally Posted by dogfood
Hide this ad by registering as a memberJune 19th, 2006 #2Registered User
- Join Date
- Aug 2003
- Location
- Sarasota, FL
- Posts
- 3,223
- Thanks
- 0
- Thanked 17 Times in 9 Posts
sorry about the absurdly long delay guys, i was travelling and im a dipshit
Sketch Book
Originally Posted by dogfood
June 20th, 2006 #3
ha!..Didn't think you'd post it....;P..and you didn't
June 20th, 2006 #4
Yay voting! My vote goes to speculart. Very moody and not really what i expected. But really nicely done!
June 20th, 2006 #5
My vote goes to speculart either. The mood, and the lighting and choice of colours are great. And I love the stag.
J.Mac was close second.
And I'm glad nobody went for a Star Gate
June 20th, 2006 #6Registered User
- Join Date
- Jan 2006
- Posts
- 35
- Thanks
- 0
- Thanked 0 Times in 0 Posts
Wow what a difficult Vote, i'm still undecided, but speculart is certainly one of the top three... *sweat* [retoric]can I vote more than once?[/retoric]
June 20th, 2006 #7
Voted for bumskee - something about the subject matter is just so phenomenal. I get a really strong sense of fate, and love how nature melds around the 'gateway'. Simple yet effective. The colour choice is very effective for a pathway to heaven.
June 20th, 2006 #8Registered User
- Join Date
- Nov 2004
- Location
- Nottingham
- Posts
- 2,447
- Thanks
- 142
- Thanked 168 Times in 123 Posts
Easily Bumskee! Without a doubt the best executed. Also the best concept. Its simple, beautiful and communicates the message.
Great work mate
BLOG> http://www.jonmccoy.blogspot.com
June 20th, 2006 #9
I voted for bumskee, I really like the colors, and its simple, I like the trail of clouds and 2 trees sitting ontop of the hill. Nice job !
Everyone else had some real nice art work and concepts.
June 20th, 2006 #10
cool stuff:
speculart, Mr. Blonde, J.Mac, yAdam, Spyro, Stewart One!
June 20th, 2006 #11
Spyro gets my vote. I love the colors, textures, and depth. The light from the sun against the dark sky is killer.
June 20th, 2006 #12
Voted for bumskee's, speculart's looked a little too dark and scary for heavens gate to me.
June 20th, 2006 #13
Heavens Gate
Wow lots of really nice art,
~ Bumskee, Cognition.sb, Speculart, J.Mac, spyroteknik, and stewart one all did very nice work and deserve recognition
But I ended up voting for Tom Garden because his piece really stood out to me, I really liked the feel of it. It seemed really creative and interesting and had what I felt was a more 'heavenly' atmosphere than the others - Nice work Tom!


text:
Kristiina Lahde's exhibition
ULTRA-PARALLEL at the Koffler Gallery
in Toronto, Jan 22 - Mar 29 2015 was favorably reviewed in:
The Star by Murray Whyte
CANADIAN ART by Amy Luo
AKIMBO by Terence Dick
Kristiina Lahde is an artist from Toronto, Canada. She received her BFA from the Nova Scotia College of Art and Design (NSCAD) in 1999.
Kristiina Lahde was nominated for the
Sobey Art Award Longlist
2013. Kristiina Lahde's work graces the cover of the winter 2014 issue of
, the issue also includes an 8 page spread of Lahde's work inside. Lahde's work is on the cover if the Spring 2013 issue of
C Magazine
. A feature article by Kristin Campell is found within. Lahdes work is in the collection of the Canada Council Art Bank.
Kristiina Lahde is represented by
MKG127, Toronto.
In my practice I alter and re-format familiar objects and materials. I select materials that are often disused or are rapidly approaching obsolescence. I alter these materials through a precise process of geometric re-organization, in which measurement and pattern play a significant roll. I am drawn to materials that carry or contain information, materials of administration or tools for measurement. These common materials include envelopes, newspapers, telephone books and measuring tapes. I seek out an internal logic of things and this leads me to subjectively shift, expand, invert or simply transform the materials.
Kristiina Lahde gratefully acknowledges the support of the Toronto Arts Council, Canada Council for the Arts and the Ontario Arts Council.


text: No recent wiki edits to this page. Menaces and Minxes of all ages will enjoy this premium pack. A luxury book with a fantastic DVD of classic Beano animation, plus a fabulous reproduction of The Beano comic from 1951 featuring the first ever Dennis the Menace comic strip!A best ever selection of Dennis the Menace strips, covering his unruly life from 1951. A wonderfully illustrated timeline of Britain's wildest boy and The Beano and Dandy comics themselves. A must-have for collectors.


text:
The Azden 105 Series Wireless Microphone Systems offer the flexibility of frequency agile operation and compact components at a modest price. With up to 92 selectable UHF frequencies, users can rely on the 105 series for clear reception in any scenario. This system includes the 105UPR camera mountable receiver and 15HT handheld microphone.
The Azden UPR 105 receiver is compact and includes a built-in shoe mount for easy camera attachment. A 1/8" (3.5mm) mini output connects to the audio inputs on cameras with the supplied cable. An optional cable (Azden MX1) provides an XLR output. In addition a separate 1/8" (3.5mm) output with independent level control provides headphone monitoring.
The Azden 15HT also features 92 selectable frequencies. Its electret-condenser capsule features a uni-directional (cardioid) polar pattern that reduces residual audio that can cause unwanted noise and feedback. An On/Off switch is provides for added control and two AA batteries provides between 6 to 8 hours of operation.
- 92 Selectable UHF Frequencies
- The 105UPR receiver and 105 series transmitters all feature 92 user selectable UHF frequencies.
- Main and Monitoring Audio Outputs
- The receiver features a main audio output and separate headphone output with independent level control.
- Camera Mountable Design
- A built-in shoe mount enables quick and easy mounting onto video cameras.


text:
The LTC®6268-10/LTC6269-10 is a single/dual 4GHz FET-input operational amplifier with extremely low input bias current and low input capacitance. It also features low input-referred current noise and voltage noise making it an ideal choice for high speed transimpedance amplifiers, and high-impedance sensor amplifiers. It is a decompensated op amp that is gain-of-10 stable.
It operates on 3.1V to 5.25V supply and consumes 16.5mA per amplifier. A shutdown feature can be used to lower power consumption when the amplifier is not in use.
4-GHz op amps achieve ultralow input bias current – [Link]
PMP9194 uses the TPS54020 synchronous-buck SWIFT converter with integrated FETs to provide a 10A/1V solution in less than 22mmx12mm of total board space area. This reference design uses a small 1.1uH inductor, 2x100uF ceramic output capacitors, and small 0402 external components to save space. The device switches at 300kHz and acheives 87% peak efficiency from a 12V input to a 1V output. The TPS54020 is ideal for powering low-voltage, high-current DSPs and FPGAs, and can be synchronized 180 degrees out-of-phase with another TPS54020 to reduce input ripple.
4.5V to 17V Input, 10-A Synchronous Buck Converter Optimized for Small Size and Low Output Voltage – [Link]
Alex Lidow @ edn.com:
For the first time in 60 years, a new higher-performance semiconductor technology is less expensive to produce than the silicon counterpart. Gallium nitride (GaN), has demonstrated both a dramatic improvement in transistor performance and the ability to be produced at a lower cost than silicon. GaN transistors have unleashed new applications as a result of their ability to switch higher voltages and higher currents faster than any transistor before. These extraordinary characteristics have ushered in new applications capable of transforming the future. But this is just the beginning.
GaN field effect transistors (FETs) are now available as discrete transistors and as monolithic half-bridges, with performance 10 times better than the best commercial silicon MOSFET. But what happens when many devices are integrated to create a system on a single chip? What happens when the performance of that chip is 100 times better than silicon?
GaN technology will transform the future – [Link]
by elektor.com:
The LTM4625 from Linear Technology is a switching mode μModule (micromodule) regulator in a tiny 6.25 mm × 6.25 mm × 5.01 mm BGA package. Like many of the newer regulator designs, the package includes the switching controller; power FETs, inductor and support components. Operating over an input voltage range of 4 V to 20 V (or 2.375 V to 20 V with an external bias supply) the LTM4625 supports an output voltage range of 0.6 V to 5.5 V, set by a single external resistor. Its high efficiency design delivers up to 5A continuous output current. Only bulk input and output capacitors are needed.
Complete 5A step-down Regulator – [Link]
Elmars writes:
If anybody is interesed, I have posed a follow up to this original post with a simple PWM LED driver, adding an ATtiny85 mCU. The post includes schematic, board layout and code for the ATtiny85. I hav tested the circuit up to 22 volts without a current limiting resistor. The FET only needs a small heat sink. Efficiency can be further improved by replacing the LM358 with an RC/LM741. The LM741 has a much sharper rise and fall time than the LM358 when run at 2KHz, resulting in the FET spending less time as a resistor. (during the slow ramp/fall the FET acts as a resistor, generating heat)
PWM Based LED Driver – [Link]
by elektor.com:
The single LTC6268 and dual LTC6269 FET-input op amps from Linear Technology feature a tiny (3 fA typical) input bias current at 25°C (peaking at 4 pA max over the entire –40°C to 125°C temperature range). Their input characteristics make them a good match for photodiode, photomultiplier and other applications using high impedance, high speed sensors. The low distortion output signal can be used by an A/D converter. A shutdown feature lowers power consumption when an amplifier is not in use.
High Speed Trans-impedance Amp – [Link]
Hydra-X is a development platform which is feature-rich, scalable, and easy to use.
The Hydra-X is based on the Power Application Controller (PAC)™ family of ICs. Hydra-X gives you the ability to execute your own code on a 32-bit ARM Cortex core, paralleled with analog resources such as multi-mode power manager (for AC-DC, DC-DC power management), configurable Analog Front-End (AFE), data converters (1 MHz 10-bit ADC, 2 precision DACs), 52 V, 72 V, 600 V gate drivers, and open drain drivers, to name a few.
With up to 14 PWM timing functions, you will find it hard to run out of timing resources. Fully configurable into PWM, input capture or output compare, these timers are expanded by a dead time generator block; extremely useful when driving external FETs in a half H-Bridge configuration and a dead time needs to be imposed in order to protect the design from shoot-through.
Hydra-X10 and Hydra-X20 by Active-Semi Inc. – [Link]
by maximintegrated.com:
The MAX17505 high-efficiency, high-voltage, synchronously rectified step-down converter with dual integrated MOSFETs operates over a 4.5V to 60V input. It delivers up to 1.7A and 0.9V to 90%VIN output voltage. Built-in compensation across the output voltage range eliminates the need for external components. The feedback (FB) regulation accuracy over -40°C to +125°C is ±1.1%. The device is available in a compact (4mm x 4mm) TQFN lead(Pb)-free package with an exposed pad. Simulation models are available.
MAX17505 – Industry's Only 60V, 1.7A Internal FET Synchronous Buck Converter – [Link]
In a paper published in Nature Communications researchers at IBM describe how they have built a silicon-based receiver chip incorporating GFETs or Graphene Field Effect Transistors (the purple structure in the photo) into the circuit. The multi-stage receiver integrated circuit consists of 3 graphene transistors, 4 inductors, 2 capacitors, and 2 resistors.
"This is the first time that someone has shown graphene devices and circuits to perform modern wireless communication functions comparable to silicon technology,"
said Supratik Guha, Director of Physical Sciences at IBM Research. In a test the team successfully used the graphene-based receiver to process a digital transmission on 4.3GHz. The binary sequence received was 01001001 01000010 01001101, which represents ASCII coding of the letters IBM.
IBM Chip uses Graphene FETs – [Link]
Industry's Only 60V, 2.5A Internal FET Synchronous Buck Converter
The MAX17503 high-efficiency, high-voltage, synchronously rectified step-down converter with dual integrated MOSFETs operates over a 4.5V to 60V input. It delivers up to 2.5A and 0.9V to 90%VIN output voltage. Built-in compensation across the output voltage range eliminates the need for external components. The feedback (FB) regulation accuracy over -40°C to +125°C is ±1.1%. The device is available in a compact (4mm x 4mm) TQFN lead(Pb)-free package with an exposed pad. Simulation models are available.
The device features a peak-current-mode control architecture with a MODE feature that can be used to operate the device in pulse-width modulation (PWM), pulse-frequency modulation (PFM), or discontinuous-conduction mode (DCM) control schemes. PWM operation provides constant frequency operation at all loads, and is useful in applications sensitive to switching frequency. PFM operation disables negative inductor current and additionally skips pulses at light loads for high efficiency. DCM features constant frequency operation down to lighter loads than PFM mode, by not skipping pulses but only disabling negative inductor current at light loads. DCM operation offers efficiency performance that lies between PWM and PFM modes. The low-resistance, on-chip MOSFETs ensure high efficiency at full load and simplify the layout.
4.5V-60V, 2.5A, High-Efficiency, Synchronous Step-Down DC-DC Converter with Internal Compensation – [Link]


text:
- Home
- Books & More
- Events & Activities
- Classes
- Research Resources
- About the Library
- Giving
- Kids
- Teens
Out Loud!
All Library locations will be closed on Saturday, July 4 in observance of Independence Day.
Tuesday, April 23, 2013
4:00pm @ Plaza Branch
Out Loud is a program where teens can hang out, share dramatic readings from popular Young Adult books and scripts, and learn about acting and storytelling under the guidance of theatre professional and librarian Meghann Henry.