Influence of sulfuric acid concentration on biohydrogen production from rice mill wastewater using pure and coculture of Enterobacter aerogenes and Citrobacter freundii

We report a concise study on the influence of sulfuric acid concentration used in the hydrolysis of rice mill wastewater on biohydrogen production using pure as well as co-culture of Enterobacter aerogenes and Citrobacter freundii. A higher total reducing sugar release of 14.2 g/L was obtained with 1.5% sulfuric acid (v/v). The effect of pH on cumulative biohydrogen production from 1.5% acid hydrolyzed rice mill wastewater was investigated using pure and coculture of Enterobacter aerogenes and Citrobacter ferundii. The fermentative hydrogen production using mixed culture showed a maximum hydrogen yield of 1.61 mol/mol sugar. In addition, about 70% reduction in chemical oxygen demand (COD) and higher volatile fatty acids (VFA) production were observed. Modified Logistic, Gompertz and Richards models were used to fit cumulative hydrogen production data whereas Logistic equation was used fit growth data. Richards model showed best fit and Logistic equation gave least error in predicting maximum hydrogen producing potential.     

Trellis coded modulation based distributed channel coding

A novel technique is described for distributed channel coding in wireless communication networks. The protocol is based on a block fading model of the multi-user uplink channel and on adapting multidimensional trellis coded modulation techniques to a coding theorem derived for the block fading channel. The coded modulation (CM) protocol is designed to optimise code performance, especially at high spectral efficiencies. The CM protocol is very simple to implement at the cooperating users. Complexity is completely transferred to the destination. The latency of the protocol is only one symbol. The CM protocol achieves full diversity order equal to the number of cooperating users and maximises coding gains by designing the code for the specific modulation used. We derive analytical results and present simulation results showing the benefits of CM protocol over other comparable schemes.     

Sampled-data and continuous-time squarers in MOS technology

Two MOS squarer circuits are presented. One implementation operates on sampled-data signals, while the second uses continuous-time operation. Both squarers achieve the square-law function with MOS transistors operating in the nonsaturation region biased with zero drain-to-source voltage. Benefits of nonsaturated operation are discussed. The sampled-data squarer is practically independent of component mismatches and clock pulse-width mismatches     

An Inexpensive Automatic Test System for Remote Supervision of Repeatered Lines

Salient features of a novel automatic fault location scheme for remote supervision of repeatered digital transmission lines is discussed. Looping back repeaters in succession by a single command on the power feed line eliminates the use of a separate supervisory cable pair. The scheme has been generalized in such a way as to facilitate its adoption to almost all type of repeaters, thus providing an inexpensive,simple supervisory scheme for a low density rural area line transmission hookups.     

Analysis of continuum by the integrated force method

The novel formulation termed the integrated force method (IFM) has been established for finite element discrete analysis. In this paper we have extended the IFM for the analysis of continuum taking circular plate as the example. The primary variables of the analysis are moments. All the continuum equations (equilibrium equations and compatibility conditions) in the field and on the boundary are obtained in moments from the stationary condition of the variational functional of the IFM. A new stress function required for the functional is defined. The variational functional yields the known equations along with the novel boundary condition identified as the boundary compatibility condition. The moment solution for the plate problem is obtained without any recourse to displacements either in the field or on the boundary. From moments, displacements are obtained by integration and boundary displacement continuity conditions. The IFM solution and boundary compatibility conditions are verified using Timoshenko's work and finite element displacement method.     

Oral cholestyramine and paregoric therapy for intractable diarrhea following surgical correction of catastrophic disease of the GI tract in neonates

Ten surgical neonates with postoperative intractable diarrhea and secondary weight loss were treated with combination cholestyramine and paregoric therapy. Within 3-5 days all infants except two showed significant clinical improvement with a decreasing number of stools, an increase in the consistency of the stool, and gradual weight gain. The exact mechanism of action of cholestyramine is not clear. It may act by binding with bile salts and/or endotoxins in the bowel lumen or decreasing the motility of the bowel. Used in combination with paregoric, a known bowel motility depressant, the doses of each medication can be kept quite low thus avoiding undesirable side effects. Medium chain triglyceride formula is helpful in some of these infants to improve fat absorption further. Medication in all of these infants has been discontinued without any adverse effects.     

Generation of analogs having potent antimicrobial and hemolytic activities with minimal changes from an inactive 16-residue peptide corresponding to the helical region of Staphylococcus aureus {delta}-toxin

The -toxin is a 26-residue peptide from Staphylococcus aureuswith the sequence formyl-MAQDIISTIGDLVKWIIDTVNKFTKK. NMR studiesindicate that the segment IISTIGDLVKWIIDTV occurs in an -helicalconformationin the toxin. A synthetic peptide correspondingto this segment, although helical, did not exhibit hemolyticactivity. Since charged residues like D and K are likely tomodulate cytolytic activity, analogs of the 16-residue peptidewere synthesized where D was systematically replaced by K. Analogsin which the first D and both Ds were replaced by K showed potentantimicrobial and hemolytic activities. The analog in whichthe second D was replaced by K was relatively less active. However,all the peptides showed an -helical structure with similar helicalcontent. The activities of the peptides were found to correlatedirectly with their ability to permeabilize model membranes.Thus, by minimal judicious replacement of charged amino acids,it should be possible to generate cytolytic peptides from shortsegments of peptide toxins.     

On short-time-scale stress wave phenomena and initiation of mechanical faults in flip-chip configurations

Small scale mechanical faults including microcracks and interfacial delaminations that compromise the integrity of solder balls and bimaterial adhesion are crucial issues impacting the reliability of flip-chip devices of small feature sizes. A small rise in junction temperature in a gigahertz flip-chip ball grid array (BGA) is found to initiate broadband, dispersive stress waves having a main frequency in the 200-800 MHz range. Numerical investigations incorporating a generalized thermoelasticity formulated to account for short-time-scale thermal-mechanical phenomena show that these waves, although fast-attenuating with the short presence of a few microseconds upon power-on, propagate in the bulk and along bonding interfaces with extreme time rate of change of stresses as high as 10/sup 11/ Pascal/s (or 10/sup 11/Watt/m/sup 3/ in equivalent units). The high frequency and high power density associated with the propagating stress waves provide potent mechanisms for the formation of geometric singularities such as microcracks, small scale delaminations, and debond at short time scales (several microseconds). These singularities would eventually lead to mechanical detachment and ultimate electrical failure subject to the coefficient of thermal expansion (CTE) mismatch-induced stress state at operating temperature on a longer time scale (several minutes).