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- What is a simple bi-directional dc-dc chopper which converts dc current source?
I want a simple bi-directional dc-dc chopper which can convert a dc current source, and be able to increase or decrease the output current.
You can use this configuration in boost converter without L and C filter. If you want filtered output then use the filter.Following
- Is it not possible to impart graphite platelets in polymer matrix composites as a filler without its modification or functionalization?
It is seen from hypothesis that modification increases the dispersion level in matrices but is there any other possible way to increase the dispersion and avoid the agglomeration problem of graphite platelets in polymer matrices.
the agglomeration can be reduced but it is so hard to be avoidedFollowing
- What does irregular absorption peaks between 270-200 nm mean in UV-spectrum?
What is the meaning and explanation of finding irregular absorbance in UV-Vis spectrum. Actulayy i have 2 overlapping absorption bands at 330 and 340 nm, but i don't know why i got irregular bands. BTW, i already made background correction using blank.
is it possible that your instrument changes radiation source around this wavelength (e.g. from deuterium to tungsten)? if there is a problem with the wavelength calibration, it may cause additional peaks at shifted wavelengthFollowing
- What are the analytical methods for determining unknown trace impurities in organic solvent?
If i wanted to quantitatively determine all impurities in an organic solvent, what current effective methods and protocols I can use?.
More specifically for a p-xylene stock.
I am expecting trace sulfur compounds (<0.003% on label) water, and p-xylene oxidation derivatives.
Joseph has brought up a good point about detection limits. The idea of limits also extends to your resources. To detect impurities at one concentration is likely to cost less than to attempt a detection of an impurity at a much lower l concentration because the equipment you will need is more highly specialized and therefore, more costly.
The purpose of your analysis will determine the level of detection that is required. This also will determine the methods and equipment. Your resources will limit what you can detect also. How much time and money do you want to spend on the task (or can you spend?) If this is a single-sample analysis, that is, if you don't plan on running many samples, it may not be worth the effort to buy expensive equipment. However, if you plan to analyze many samples, it may be worth the expense and effort.
- Has anyone ever rigourously proven the distance formula before?
The only proofs I ever saw relied on intuition. The proof by similar triangles did something sort of like assume without proof that distance satisfies the following conditions:
- The distance of every nonnegative real number r is r.
- The distance of any complex number is a nonnegative real number.
- The distance of any complex number is equal to the distance of its complex conjugate.
- For any 2 complex numbers, the distance of their product is equal to the product of their distances.
The proof by area assumes without proof that a rotation never changes the area of an object where a rotation is defined to be a complex multiplication by a complex number with a distance of 1. Maybe the facts that those 2 proofs assumed have been previously proven.
Except for the page I wrote myself at https://proofwiki.org/wiki/User:Blackbombchu/Sandbox/Complex_magnitude_is_distributive_over_multiplication, I never saw any pages that define the distance of (x, y) to be sqrt(x^2 + y^2) without justification then prove the fourth condition from it.
I never saw any full proof in pages other people wrote: only in ones I wrote myself such as http://speedydeletion.wikia.com/wiki/Distance_and_rotation.
Perhaps just like some mathematicians don't feel the need to understand a mathematical proof of a statement when they have a computer-assisted proof, some mathematicians don't feel the need for a proof that there exists a distance function satisfying those 4 conditions when they instead have a physical proof, which is that they never observed a rigid object make an operation other than a rotation.
Since writing simple is much more difficult than writing complicated one better learns math from the masters rather than from the apprentices. This gives simplicity a chance. The natural course of things is dictated by the second law of thermodynamics: things grow in size and complexity while content becomes more and more hidden.Following
- Small and medium-sized enterprises (SMEs) and Islamic finance. what's next ?
Experiences from across the Mena region indicate that a number of SMEs, estimated at about 20%-25% of the total, prefer sharia-compliant products . Thus, better risk management protocols would strengthen lenders’ confidence to create more sharia-compliant financing options. Risk management frameworks that protect lender's’ rights and address their concerns for transparent information could not only strengthen the evolution of Islamic finance with respect to SMEs, but allow traditional banks to develop more confidence in lending to SMEs, as well.
Your opinion matters and will be gratefully appreciated.
As a novice in this subject I would only say that in any field of business, entrepreneur or trade marketing, one of the thumb rule is honesty. Honesty between employees, employees and employer, Customer. To maintain this essential quality one must respect hard work of others in terms of salary, wages, or sometimes even respect.
Now coming to finance It looks awkward but Right "customer doesnot knows what it wants" and as SME are in immediate vicinity of customers they have an direct impact on customers and impact from customers. So even some laws are to be made transparent and unbiased to any firm so that these SME are functional.
As told money is good in transit but not in steady state.
Any info or criticism is welcomed.Following
- Does the Barkhausen criterion for oscillation apply for linear circuits only?
In several documents it is claimed that Barkhausens (necessary) criterion for a feedback circuit to oscillate applies to linear active circuits only (example:https://en.wikipedia.org/wiki/Barkhausen_stability_criterion).
For my opinion, this requirement is wrong.
In contrary, stable "sinusoidal" oscillations require a smooth non-linearity of the loop gain function. Otherwise, a hard-limiting (clipping) of the oscillation amplitude (which also is a non-linear effect) occurs.
Shouldn`t we recommend a rewording in wkipedia?
Now about the oscillating circuit of two active RC integrators in a closed-loop...
I can understand the phase condition. Shortly, we need a total 360 degrees phase shift to obtain an oscillation. The first integrator gives 90 degrees, the second integrator provides another 90 degrees, and the act of invertion gives the final 180 degrees (90 + 90 + 180 = 360). But I cannot understand what will be the amplitude of these oscillations if there is no clipping?Following
- Can I use a matrix converter for integration of solar and wind energy systems?
By using Matrix Indirect converter can i combine both solar and wind energy?
If not, What are the drawbacks?
Indirect matrix converter topology is best suited for drives application where ac-ac conversion is needed. In case of renewable application indirect topology can be used but it should be boost converter+inverter type topology. Choose any kind of boost converter and inverter topology.Following
- How to Restart an ABAQUS analysis after the analysis has been stopped by URDFIL?
I am working on problem of Node Release technique.In this technique I have to run the model till the specified node has archived the CTOD displacement.Then I am able to stop the analysis using URDFIL subroutine.Now I have to restart the analysis and use the data for nodal forces and reactions to be applied in further analysis and I have to release one of the fixed node till few nodes and show that the crack is propagating. I am new to ABAQUS programming so I am finding great difficulty in running analysis after it is terminated. Please help !Following
- I have to suggest a reviewer for my paper Submission.????
My paper on EDM process and their parameters effect on super alloy.
Please, let me know who are interested to review my manuscript.Following
- What is the difference between low image features and semantic image features?
Regarding image features:
1) What is the difference between low image features and semantic image features?
2) What is the semantic gap?
This is a good question.
In terms of the first question, a semantic feature describes the visual content of an image by correlating low level features such as colour, gradient orientation with the content of an image scene. For example, correlate an extracted color such as blue with the sea or sky, white with a building, and so on. For more about this, see
Imaging and vision laboratory:
In terms of the second question, the separation between the visual content in a digital image and semantic descriptions is known as the semantic gap. For example, consider the separation between edge pixel gradient orientation vs. round or oblong or pointed shape. For more about this, see
Hao Ma, Jianke Zhu, Michael R. Lyu, Fellow, IEEE, and Irwin King, Senior Member, IEEE, Bridging the Semantic Gap between Image Contents and Tags, JOURNAL OF LATEX CLASS FILES, VOL. 6, NO. 1, JANUARY 2007:
- Is there any freely available software or server for protein protein interaction & validating their binding energy and interacting amino acids?
Is there any freely available software or server for protein protein interaction & validating their binding energy and interacting amino acids?
You can use Patchdock (http://bioinfo3d.cs.tau.ac.il/PatchDock/) and Firedock (http://bioinfo3d.cs.tau.ac.il/FireDock/) for Pr-Pr interaction and do CoComap (https://www.molnac.unisa.it/BioTools/cocomaps/) for further analysis.Following
- Definition of high Torque Motors ?
When can we say that an electric motor is a high torque motor ?
Is it according to its torque, diameter,.... ?
Nobody is surprised that a higher weight produces a higher torque. If fact it is normal that a higher diameter produces more torque. For a torque at lower speed the iron losses are not so important. In fact the limit is rather the continuous force per surface air gap for a given copper loss. Some benchmark is a continous force of 20kN/m^2 air gap using slot depth of 25mm and a copper loss of 10kW/m^2 air gap surface.
In practice only permanent magnet motors get up to this limit, as exciting windings or rotor conductor losses also add to the "copper loss" per surface. Outer rotor PM motors have a higher air gap diameter and will produce more torque for a given outer diameter and also motor weight.Following
- Effect of humic acid for cement-treated soils??
When humic acid add into cement-treated soils, calcium ion may react with humic acid, and then occur complextion compound, calcium humate. I want to fine the information of SEM and XRD for calcium humate.
Dear Gyeongo Kang,
In your case find EDX for % of all element. Because Cl is not single element whose responsible for humic acid. To check its effect is very clear After than EDX analysis.
All the bestFollowing
- Chest compressions in traumatic cardiac arrest?
I'm doing some work on improving outcomes in patients who suffer traumatic cardiac arrest.
Case history: a 30 year old male motorcyclist is brought to the emergency department having crashed his motorbike into a tree. He has multiple injuries, but was conscious with a palpable pulse at scene. He deteriorates en route. On arrival in your resuscitation room he is not breathing and has no palpable pulse.
Quick poll - who would initiate chest compressions in this case?
Jason, another aspect crossed my mind. Even though only 3 % of blunt heart asystole survivors continue life without neurologic sequelae, guidelines are made for high volume resuscitation rooms and for restricted health cost funding scenarios. Even if a percentage is as low as 1%, it may not say anything for your single patient. He survives or dies. Nevertheless, in a crowded mass casualty setting with 5 penetrating and one blunt cardiac arrest, you know to whom you would allocate the least ressources.
- How can we know carbon element for polymer by SEM-EDX?
I have done SEM-EDX for my polymer, but the carbon element has not seen on it. My polymer content by two benzene ring? is there density effect of benzene ring?
Thank you for discussion
Thank you Dr. Slipper for explaining thing in detail.
Sorry khusna for coming in between but i thought it is always good to get some idea from experienced person like Dr. Slipper.
- Efficient image segmentation methods?
Graphcut can produce good segmentation results.
However, it usually requires EM iterations. Anyone knows any efficient methods? preferably fast convergence as I would like to apply to many images.
In this link you find several code of efficient segmentation methods.
- What are softwares to predict tertiary and quarternary protein structure from a sequence and how to validate it?
I have the sequence of a protein and I want to predict the structure. Any suggestions
- Can anyone help with grammaticality judgments in English?
This is for native speakers of English. How do you find the following sentences? Are they grammatical? Please provide me with the meaning if possible. (Please note the indexation between the pronouns and the nouns.) Thanks in advance!
(1) a. This is the type of story about Obama_i that people who hear think he_i will be angry about.
(1) b. This is the type of story about Obama_i that people who tell him_i to ignore end up talking about.
(2) a. Which picture of John_i did he_i like and Mary dislike?
(2) b. Which picture of John_i did Mary like and he_i dislike? (Citko 2005)
(3) a. Criticize himself, John will but Mary won’t.
(3) b. Criticize himself, Mary will but John won’t.
(4) a. It is only himself_i that [John_i has to blame and Mary will gloat over].
(4) b. It is only himself_i that [Mary has to blame and John_i will gloat over].
(5) a. It is only himself_i that people who know think John_i should blame.
(5) b. It is only themselves_i that people_i who blame will realize John has conned.
(6) a. She is the kind of mother_i that teachers who have to send her_i child home to always end up despising.
(6) b. She is the kind of mother_i that teachers who meet have no problem sending her_i child home to.
(7) a. Which picture of himself_i does John_i like and Mary dislike?
(7) b. Which picture of himself_i did Mary paint and John _i sell?
(8) a. How many portraits of herself_i did the woman_i who commissioned end up asking that artist to take back?
(8) b. How many portraits of himself_i did the woman_i who commissioned end up asking that artist to take back?
(9) a. Over himself, John pulled a blanket and Mary threw a rug.
(9) b. Over himself, Mary pulled a blanket and John threw a rug.
(10) a. Which picture of John_j did he_j like and Mary dislike?
(10) b. Which picture of John_j did Mary like and he_j dislike?
(11) a. This is the type of story about Obama_i that people who hear think he_i will be angry about.
(11) b. This is the type of story about Obama_i that people who tell him_i to ignore always end up talking about.
Thank you for clarifying the purpose of your study. It is an area of linguistics that I have not explored. I have an interest in comparative linguistics so I would like to learn more about similarities and differences in the ways that native and non-native speakers process language. My opinion about language rules tends to fall somewhat on the prescriptive side. The purpose of grammar, spelling, and punctuation is and should be clarity of writing - to make the meaning clear. However, English has some grammatical and punctuation anomalies that seem not to make any sense. I can see some merit in a descriptive study.
Example: She runs, they run. "They" is plural and "she" is singular and yet the singular form of the verb takes the "s" and the plural form does not. This is the opposite of how nouns are declined and also opposite of the rule in some other languages.
It is interesting to note that one can identify the language group of a non-native speaker by observing the grammatical mistakes. For example in the Romance languages, e.g. Italian and French, it is perfectly acceptable to use double negatives and wrong if you don't. The double negative reinforces the negativity. In English, the second negative cancels the first - the opposite mind set. Therefore, when a person says or writes a sentence with a double negative one can infer that the speaker's native language is from the Romance group.
Similarly, Chinese has no verb conjugations. Even Americans whose native language is Chinese have a hard time understanding the concept of conjugation. If someone says, "Today I go to store; tomorrow I go to store," it would seem that the information about when the action took place is already stated in "today" and "tomorrow." Therefore, the verb logically does not need to change. If someone does not conjugate verbs it is a hint that their native language may be Chinese.
An indication that the native language of a speaker is English is the use of single-vowel diphthongs. This is an obstacle one has to overcome when learning Italian, which has not single-vowel diphthongs (all Italian diphthongs require two vowels.)
- How do I correlate "dynamic displacement amplitude (in um)" to "dynamic strain amplitude (in %)" in DMA analysis?
Hello. We are starting our studies in DMA analysis and looking in publications is typically mentioned that the amplitude used in the analysis as %strain instead of um units. Although many books suggest to use 0,1% strain I steel can't find the correlation between displacement amplitude (um) and strain amplitude (%). Thanks in advance!Following
- How to know what gene/protein sequence analysis technology to use?
Previously I posted a question about how I might go about comparing homologous genes across different species, and I received some very informative responses that have helped quite a bit and am very thankful to the individuals who responded. In the responses(I have attached the thread link below) there were references to many technologies of which I am very unfamiliar with. The ones mentioned where PHAST, T-Coffee, MAFFT, MUSCLE, SATe, PASTA, and CLUSTAL. Any links to any tutorials of applications of these technologies and/or a brief overview of modern computational biology technologies would be greatly appreciated.
These are the packages, that accept sequences (3 or more) as input and perform multiple sequence alignment with respect to you target gene sequences.
Well, You should read a book of following link to know basic and detail about modern bioinformatics nomenclature, techniques, tools/packages and all.
- How can I solve the following nonlinear differential equation?.
The kinetics of damage is given in differential form. The Differential equation is attached in jpg format.In the equation take n=3,i(=1,2,3) do not denote index summation. The damage in three orthogonal directions is to be found.Which numerical method I should follow to obtain D1,D2,D3.What are the reference books or papers to be followed to obtain the numerical solution of the given differential equation?Following
- Could somebody suggest some methodology(ies) for analyzing and synthesizing systems of systems (or complex engineering systems)?
The key question for desgning complex systems, cosisting in a set of interrelated betwween them systems each of them constitute itselef a complex systems consists in systems.structures organization based in its mathematical description
That kind of systems of system is presented in complex engineering designing or redesigning (lile aqueducts of big cities), complex organizations like very big companies, systems for territories developing, for organization the transport or energetic systems in countries, etc.
The more important questions to be solved consists in systems structures organizarion, developing methods for conciliation betwwen components in theses structures, optimal organizations calculations algorithms, etc.
I am working over this problem theorically and practically during many year. On it solutions are ocupied vethe most important universities in the world, but it is available no much scientific informationFollowing
- How to take into account strangler figs in calculations of basal areas? In tropical forest inventories, strangler figs are common. How estimate the basal area of a strangler figs and their tree hosts? This issue is very imporatant as it may lead to important mistakes in total basal area estimation.
Did you find a suitable method? I am facing a similar issue. I am interested determining the Basal area of fig trees. Both free standing, multiple stemmed individuals and/or parasitic stranglers. Is there an effective way to determine basal area short of measuring every stem?Following
- Does anyone know nailed horseshoes from a well documented Roman context?
I'm interested in literature about nailed horse shoes (not hipposandals) from well documented Roman contexts.
The existence of nailed horseshoes has been denied recently by
Simone Martini, Mittelalterliche und neuzeitliche Hufeisen im Rheinischen Landesmuseum Trier. Funde und Ausgrabungen im Bezirk Trier 42, 2010, 70-90.
Insa Lingens, Die Entwicklung der Hufpflege und des Hufbeschlags von der Antike bis zur Neuzeit unter besonderer Berücksichtigung des Hufbeschlags bei der Hufrehe (PhD thesis, Berlin 2008).
there is no clear evidence for nailed horseshoes from Roman times.
Currently I'm working on artefacts excavated the 60ies near Obermendig (Rhineland-Palatinate, Germany) in a late Roman granary (horreum) presumably fortified as a burgus. 99% of these finds date to the 4th and 5th centuries AD, but there are some few late medieval objects from the site. There are two horseshoes among the finds. May they be Roman? Any advice would be welcome.
PS: Please find drawings of the horseshoes attached.
the British Museum managed to maintain ease and clarity:
"Roman Britain, 1st-2nd century AD
From Sun Street, Bishopsgate, London
Nailed horseshoes were known but rarely used by the Romans. Much more common were iron hipposandals, a form of temporary shoe that could be fastened to the hoof for use on metalled roads and easily removed when not required. Hipposandals were probably intended for draught animals: horses, ponies or mules. Because the animal's hoof exerted great pressure, they had to be made from thick metal. The underside was often given a tread to increase the animal's grip on the surface of the road.
Like many Roman metal finds from London, this large example is in almost new condition, having been preserved in waterlogged ground."
- How can I calculate RMSD between two ligands (crystal and docked)?
How can I calculate the RMSD value between crystal and docked structure of ligand using pyrx or VMD? Is it possible to calculate RMSD using pymol between the two ligands (crystal and docked)?
load the molecule, go to Extension menu, Analysis ----->RMSD calculator and set the number and click RMSD.
For ligand, load and do the same process.Following
- In case of deposited film on any electrode (say graphite), what might be the reasons for not getting any characteristic peaks from Powdr XRD analysis?
I am getting only the subtrate (electrode) peaks and not the electrodeposited samples peaks although i can see visually the smooth deposition of Ni and Ni(OH)2 onto it. I wonder what are the possibilities of not getting any PXRD peaks although EDAX and other elemental analysis prove its presence. The thickness of the deposition is about ~ 5-6 micrometers (from AFM and SEM cross sectional image).
Please suggest what might be the case.
One other thought - are you using grazing incidence? Set the tube angle at a suitable low value and scan only the detector to see the film.Following
- Is Chalmers' so-called "hard problem" in consciousness real?
In his 2014 book "Consciousness and the Brain: Deciphering How the Brain Codes Our Thoughts" Stanislas Dehaene wrote "Chalmers, a philosopher of the University of Arizona, is famous for introducing a distinction between the easy and the hard problems. The easy problem of consciousness, he argues, consists in explaining the many functions of the brain: how do we recognize a face, a word, or a landscape? How do we extract information form the senses and use it to guide our behavior? How do we generate sentences to describe what we feel?
“Although all these questions are associated with consciousness,” Chalmers argues, “they all concern the objective mechanisms of the cognitive system, and consequently, we have every reason to expect that continued work in cognitive psychology and neuroscience will answer them. By contrast the hard problem is the “question of how physical processes in the brain give rise to subjective experience … the way things feel for the subject. When we see for example, we experience visual sensations, such as that of vivid blue. Or think of the ineffable sound of a distant oboe, the agony of an intense pain, the sparkle of happiness or the meditative quality of a moment lost in thought … It is these phenomena that poses the real mystery of the mind”."
Stanislas Dehaene's opinion is "that Chalmers swapped the labels: it is the “easy” problem that is hard, while the “hard” problem just seems hard because it engages ill-defined intuitions. Once our intuition is educated by cognitive neuroscience and computer simulations, Chalmers’ “hard problem” will evaporate".
Personally, I agree with Stanislas Dehaene's opinion.
I have not had the time yet to look more into "Riggs and Day", but it would be interesting to follow it up.Following
- How much energy is required to cook the potato?
i am working in a project on solar cooking using phase change material ,and i choose potato and i want to do the energy balance.i refer articles but i didn't get the information related to potato.Following
- Which agarose percent should I use to quality check genomic DNA by gel electrophoresis?
My supervisor usually use 1% agarose gel to check the DNA genomic quality of human cancer cells. But in this attached book, it is stated that it should use agarose gel with percentage less than 1%. What percent of agarose gel do you usually use to check the quality? Thanks in advance.Following