Problems multiple

It is rare for there to be two process pinches in a problem. Multiple pinches usually arise from the introduction of additional utilities causing utility pinches. However, cases such as that shown in Fig. 16.18 are not uncommon, where there is, strictly speaking, only one pinch (one place where occurs), but there is a near-pinch. This... 

One of the great frustrations you may encounter during an organic chemistry exam is expecting to know the answer to a retrosynthetic analysis question immediately upon first reading the problem. Save yourself this frustration and accept the fact that you need to read and reread the problem multiple times. 

Unfortunately, in chemical and biological engineering problems multiple roots or near multiple roots occur often for example, look at Figure 3.2 on p. 71 and the slanted intersections marked by (1), (2), and (3). These force us to devise specific better numerical methods for such problems in Sections 3.1 and 3.2. 

Third, the reference method results should be compared with measurements on an equivalent amount of material, particularly if the sample is not homogeneous. In many instruments, Raman spectra are collected only from the sample located in a small focal volume. If that material is not representative of the bulk, then the Raman results will appear to be biased or erroneous. To avoid this problem, multiple sequential spectra are added together to represent an effectively larger composite sample. Alternatively, a larger area could be sampled if the instrument design permits it. If it were desired to study within-sample inhomogeneity, short acquisition times could be used. 

PEO-PPO-PEO triblock copolymers (Pluronics or Poloxamers) form reversible physically cross-linked hydrogels under certain concentration range and temperature. The use of this system in tissue engineering is scarce because of its inability to degrade. Di- or tri-block copolymers of PEG with PLA have been developed to overcome this problem. Multiple blocks of PEG and PLA, synthesized by condensation reaction of L-lactic acid in the presence of succinic acid. 

Persons at greatest risk for NSAID hemodynamic nephropathy generally have pre-existing renal insufficiency, medical problems associated with high plasma renin activity (hepatic disease with ascites, decompensated congestive heart failure, or intravascular volume depletion), or systemic lupus erythematosus. Additional risk factors include atherosclerotic cardiovascular disease and diuretic therapy. The elderly are also at higher risk due to interaction of prevalent medical problems, multiple drug therapies, and reduced renal hemodynamics. Advanced age, however, has not been shown to be an independent risk factor for toxicity in limited trials in otherwise healthy elderly subjects. Combined NSAID and ACEl or ARB therapy is also a concern and should be avoided. 

Cardiac resynchronization therapy (CRT) for systolic congestive heart failure (CHF) represents a new paradigm in cardiology the use of an electrical therapy (cardiac pacing) to treat a mechanical problem. Multiple randomized clinical trials have proven that resynchronization therapy improves symptoms and functional status, increases quality of life, reduces hospitalizations, and prolongs survival in appropriately selected patients. As a result, this therapy has been quickly established as a standard treatment for patients with severe left ventricular dysfunction, moderate-to-severely symptomatic CHF despite optimal medical therapy, and prolonged QRS duration (1,2). 

For samples subject to the general elution problem, multiple development with two different solvents can provide simultaneous resolution for both weakly and strongly adsorbed sample components [e.g.. Ref. (32)]. 

Determination of the structure of natural and synthetic xanthones using spectroscopy is considerably more difficult than for chromones and flavones but publication of the analysis of spectra of known compounds assists with this problem. Multiple linear regression analysis has been applied to predict 13C n.m.r. shift increments for 272 polymethoxyxanthones and their... 

The clinical detection of the borders of BCCs and SCCs, particularly in anatomically difficult sites such as the face, is a frequent problem. Multiple surgical procedures can become necessary for complete tumor removal. FDAP was demonstrated to be very effective in detecting and also demarcating clinically ill-defined tumor tissue (Figure 5) [111]. Thus, we recommend FDAP as a useful easy technique to visualize and detect the extent of the tumor preoperatively. 

LC chromatography could be performed independently from the NMR experiments Since the chromatography is not stopped, issues with peak broadening in the stop-flow mode are eliminated. Eliminates cross contamination problems Multiple experiments on each sample are possible including Heteronuclear experiments such as >H-15n... 

In a typical problem, multiple reactions are taking place in a multiphase system at fixed T and P, and we are to compute the equilibrium compositions of all phases. At this point, such calculations raise no new thermodynamic issues for example, for (R independent reactions occmrring among C species distributed between phases a and P, the problem is to solve the phase-equilibrium criteria... 

Because polymers cannot be made specific to only sorb a single chemical, false positive alarms may occur when various unknown chemicals are being sorbed onto polymer. To minimize this false alarm problem, multiple SAW sensors with different polymer coatings are used in a single detector. The combined response patterns can improve detection reliability. For each chemical of interest, the response pattern is established via comparison with standardized samples. The pattern recognition is based on comparison between the output signals and the established response pattern stored in the detector s databases. 

Almost every study in the multi-objective network design models uses an interactive approach to solve the problem. Multiple efficient solutions are generated and presented to the DM. The DM guides the procedure until a best compromise solution is reached. 

In engineering terms this is often referred to as a special multiple-level-multiple-variable optimisation problem. Multiple-level means that each of the parameters such as specification, comprises requirements, and is with varying degrees of complexity. Multiple-variable implies that there is more than one variable or factor involved. Optimisation aims... 

ALiTHEEN NB, MCCLURE s, MCCULLAGH p (2010), B-cell development one problem, multiple solutions , Immunol Cell BioZ, 88,445-50. 

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