The Principle of Critical Energy as a Transdisciplinary Principle with Interdisciplinary Applications

The principle of critical energy (PCE) is a transdisciplinary principle that may be used in all chapters of sciences for superposition and/or cumulation of different external actions (mechanical, thermal, magnetic, electrical, chemical, etc.) It may be used for lifetime evaluation of engineering structures, as well as for living organisms, by taking into account the influences due to pollution, due to internal deterioration, due to preloading or residual stresses, etc. In this paper, we explain what PCE is, how it may be practically used and the interdependences between the terms comprised in its general relation. PCE was applied for solving problems of superposition of external actions and internal deteriorations in the following chapters of sciences: mechanical engineering, thermomechanical-chemical loadings, multiple pollution, medical field and viscoelasticity. It was compared with synergy theory and with catastrophe theory

Extruder Performance based on a Correlated Extruder Head-screw-barrel Unit Working Field

A number of inventions, and theoretical and experimental research allowed to increase the thermal homogenous melt flow-rate delivered by the screw. On the other hand, quality of the extruded product depends on geometrical considerations of the extrusion head and on a large scale on the rheological behaviour (viscous and elastic) In the case of plastic materials extrusion, the nonharmonizing of the screw-barrel unit design with the extrusion head, leads to products loaded with internal stresses and cross-sectional non-homogeneity. The life span of these products is relatively small. For pipes, for example, fracture before due time leads to environment pollution with the transported substances. To avoid such situations, the analysis of the extrusion head working field is necessary, in accordance with the extrusion process parameters, rheological behaviour of the polymer melt, product quality conditions as well as economic considerations. Extruders have been improved especially after 1953, when the first in-depth theoretical analyses of the extrusion process have been published The screw with barrier flight was designed Experimental and theoretical research concerning the extruder flow-rate, the established flow-rate calculus relationships [31 -40], constructive solutions and the corresponding relationships of the intensive homogenizing zones [41 -47], as well as those referring to thermal nonhomogeneity and temperature variation of the melt in the screw channel [48 -51] led to an increase in the screw capable flow-rate. This advantage, created by the results of research and inventions related to the screw-barrel unit, was limited due to conditions imposed by the flow pattern in the extrusion head, especially in the entry zone and by the end channel at the extrusion head exit, for viscouselastic polymer melts. To address these issues the spiral mandrel before the end channel was invented, allowing the cross-flow of the melt currents and avoiding the effect of melt currents separation, characteristic to "classic" extrusion heads, with spider mandrel To optimize the extrusion process, the extruder optimization diagram was drawn initially with coordinate flow-rate -pressure at screw channel exit [52; 53]. Later on, the working field of the extruder head was defined and drawn, with coordinate flow-rate -pressure at extrusion head entry [54 -57]. In this paper is proposed an enhanced and completed solution of the method developed in papers [54; 55] for the drawing of the extrusion head working field. Extruder head-screw-barrel unit correlated working field In the extrusion head the melt pressure decreases from p e , at extrusion head entry, to a value p f in the cross-section at the end channel exit. Pressure p f can be greater or equal to atmospheric pressure, p 0 ; this depends on the extrusion head geometry, flow velocity and elastic properties of the melt. Melt temperature in the extrusion head is considered constant and equal to the extrusion temperature, T e , characteristic for each polymer. Extrusion head working field (in the semi-plane limited by the coordinates G m -flow-rate -and p e ) is obtained at the interior of the contour determined by the intersection of the following curves

The laparoscopic treatment of perforated duodenal ulcer in Romania – a multicentric study

Clinica Chirurgie 2, Timișoara, România, Clinica Chirurgie, Spitalul de Urgență, București, Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011Aims. This retrospective study was evaluated the results of laparoscopic treatment of the perforated duodenal ulcer (PDU) in 6 Romanian centres with an important experience in laparoscopic surgery.Methods. Between 2000 and 2010, 221 patients (38 females and 183 men) aged from 18 to 78 years, were operated laparoscopicaly for PDU, by using 3 (66.0%), 4 (27%) or 5 (7.0%) trocars. Forty six (20.8%) of them had a weak, 143(64.7%) an important and 32(14.5%) a grave peritonitis. Procedures performed were: simple suture 84(38.1%) patients, suture with epiplonoplasty 135(61.1%) patients, only epiplonoplasty 1(0.4%) patients, excision with suture 1(0.4%) patients. All patients had abundant peritoneal cavity washing and tub drainage (1-3 tubs).Results. The interventions lasted between 30 and 120 min, with an average of 63 min. No mortality was reported. Postoperative oral nutrition began after 24 hours for 114(51.6%) patients and after intestinal transit has restarted for 107(48.4%) patients. The intestinal transit has restarted after 1-6 days (average 3.5 days), depending of the gravity of peritonitis. Complications were: parietal infections 3 (1.3%), duodenal fistula 1 (0.4%), abdominal abcesses 1(0.4%), digestive haemorrhage 1(0.4%) and duodenal stenosis 1 (0.4%). Hospitalization lasted between 2 and 13 days (average 5.5 days). In comparison with open techniques, patients had the same intravenous perfusions, less pain, less antibiotics, less dressings, less complications during postoperative evolution. Conclusion. Laparoscopic treatment of PDU is safe even in case of severe peritonitis, with faster patient’s recovery. with less complications and with less postoperative medical care than open procedures. Aims. This retrospective study was evaluated the results of laparoscopic treatment of the perforated duodenal ulcer (PDU) in 6 Romanian centres with an important experience in laparoscopic surgery.Methods. Between 2000 and 2010, 221 patients (38 females and 183 men) aged from 18 to 78 years, were operated laparoscopicaly for PDU, by using 3 (66.0%), 4 (27%) or 5 (7.0%) trocars. Forty six (20.8%) of them had a weak, 143(64.7%) an important and 32(14.5%) a grave peritonitis. Procedures performed were: simple suture 84(38.1%) patients, suture with epiplonoplasty 135(61.1%) patients, only epiplonoplasty 1(0.4%) patients, excision with suture 1(0.4%) patients. All patients had abundant peritoneal cavity washing and tub drainage (1-3 tubs). Results. The interventions lasted between 30 and 120 min, with an average of 63 min. No mortality was reported. Postoperative oral nutrition began after 24 hours for 114(51.6%) patients and after intestinal transit has restarted for 107(48.4%) patients. The intestinal transit has restarted after 1-6 days (average 3.5 days), depending of the gravity of peritonitis. Complications were: parietal infections 3 (1.3%), duodenal fistula 1 (0.4%), abdominal abcesses 1(0.4%), digestive haemorrhage 1(0.4%) and duodenal stenosis 1 (0.4%). Hospitalization lasted between 2 and 13 days (average 5.5 days). In comparison with open techniques, patients had the same intravenous perfusions, less pain, less antibiotics, less dressings, less complications during postoperative evolution. Conclusion. Laparoscopic treatment of PDU is safe even in case of severe peritonitis, with faster patient’s recovery. with less complications and with less postoperative medical care than open procedures

Modelling of Batch Lactic Acid Fermentation in the Presence of Anionic Clay

U radu je provedena šaržna fermentacija mlijeka inokuliranog mliječno-kiselim bakterijama u statičnoj kulturi, te u ultrazvučnoj kupelji provedena uz dodatak hidrotalcita (gline). Ispitan je utjecaj temperature (t=38-43 °C), omjera gline i mlijeka (R=1-7,5 g/L) te ultrazvuka (ν=0 i 35 kHz) na dinamiku procesa. Odabran je matematički model koji opisuje kinetiku fermentacije i procijenjuje parametre prema eksperimentalno dobivenim podacima, a odnos je između eksperimentalnih i simuliranih podataka bio dobar. Stoga je zaključeno da se model može primijeniti za predviđanje dinamike šaržne mliječno-kisele fermentacije prema vrijednostima varijabli dobivenih u ovom eksperimentu. Provedena je statistička analiza pomoću 23 faktorskog plana, da bi se primjenom eksperimentalnog i regresijskog modela utvrdio utjecaj faktora t, R i ν na kinetiku fermentacije.Batch fermentation of milk inoculated with lactic acid bacteria was conducted in the presence of hydrotalcite-type anionic clay under static and ultrasonic conditions. An experimental study of the effect of fermentation temperature (t=38–43 °C), clay/milk ratio (R=1–7.5 g/L) and ultrasonic field (ν=0 and 35 kHz) on process dynamics was performed. A mathematical model was selected to describe the fermentation process kinetics and its parameters were estimated based on experimental data. A good agreement between the experimental and simulated results was achieved. Consequently, the model can be employed to predict the dynamics of batch lactic acid fermentation with values of process variables in the studied ranges. A statistical analysis of the data based on a 23 factorial experiment was performed in order to express experimental and model-regressed process responses depending on t, R and ν factors

The Vascularization Pattern of the Colon and Surgical Decision in Esophageal Reconstruction with Colon. A Selective SMA and IMA Arteriographic Study

Rezumat Pattern-ul de vascularizaåie al colonului aei decizia chirurgicalã în reconstrucåia esofagianã cu colon -studiu arteriografic selectiv al AMS aei AMI Introducere: Indiferent de tehnica reconstructivã, conceptele de fundamentare din reconstrucåia visceralã au ca baza principalã suportul vascular necesar pentru grefonul de substituåie. Particularitãåile vasculare individuale pot înclina sau chiar obliga chirurgul la o anumitã opåiune cãtre unul sau altul dintre procedee. De aceea, vascularizaåia este, fãrã îndoialã, factorul care dominã mobilizarea colonului pentru reconstrucåia esofagianã. Material aei metodã: Studiul nostru arteriografic aei-a propus o investigaåie asupra tiparului vascular al celor douã surse principale ce participã prin vasele emergente la irigarea arterialã a colonului: a. mezentericã superioarã (AMS) respectiv a. mezentericã inferioarã (AMI). Nu am avut în vedere selectarea pacienåilor dupã un anumit criteriu dupã cum nu am realizat nici o excludere dintr-un anumit considerent. Lotul de studiu a constat din 49 de pacienåi care s-au prezentat în clinicã pentru o tehnicã reconstructivã, toåi aparåinând perioadei 2000-2010. În intervalul 1981-2012, au fost efectuate 187 de tehnici reconstructive pentru o indicaåie postcausticã. Din totalul de 49 de pacienåi, 11 bolnavi suferiserã intervenåii chirurgicale abdominale majore iar dintre aceaetia, 5 cu tentative nereuaeite de reconstrucåie. Rezultate: Din cei 49 de pacienåi la care s-a efectuat explorarea, arteriografia a evidenåiat o situaåie favorabilã reconstrucåiei la 31 dintre aceştia. La ceilalåi 18 pacienåi au fost identificate anomalii ori distribuåii atipice, 5 ale AMS respectiv 13 ale AMI. Decizia operatorie a fost ajustatã la 22 de bolnavi. Un lucru important de semnalat dpdv predictiv asupra viscerul de mobilizat: nu am avut necroze de grefon la pacienåii cu examinare arteriograficã preoperatorie. Concluzii: Dictate de necesitatea unei bune mobilizãri, ligaturile arteriale trebuie adaptate şi modificate în funcåie de particularitãåile de distribuåie vascularã, astfel încât sã se menåinã un flux sangvin suficient în arcada marginalã pânã la nivelul secåiunilor colice şi, implicit, în arterele drepte din vecinãtatea acestora. main grounds the mandatory vascular support for the graft replacement. Individual vascular particularities can influence or even oblige the surgeon to choose a certain procedure. This is why the vascularization is beyond doubt the dominant factor in mobilizing the colon for reconstruction. Material and method: Our arteriographic study entails an investigation upon the vascularization pattern of the two main sources that participate in the arterial irrigation of the colon via the emerging vessels: superior mesenteric artery (SMA) and inferior mesenteric artery (IMA). We did not consider certain patients upon a specific criterion; also, we did not exclude any patients due to various reasons. We took into account 49 patients as study group, all of them having registered into the clinic for a reconstructive technique, throughout the years from 2000 to 2010. From 1981 to 2012 there have been 187 reconstructive techniques performed due to post caustic pathology. From a total of 49 patients, 11 had suffered major abdominal surgeries, 5 of which had had unsuccessful reconstructive attempts. Results: Out of the 49 patients on whom we have performed the exploration, arteriography showed a favorable situation for reconstruction in 31 of them. In the other 18 patients anomalies or atypical distributions were identified, in 5 of the SMA and in 13 of the IMA, respectively. Operative decision was modified in 22 patients. One important thing to note from the point of view of the segment to be moved: we had no graft necrosis in patients with preoperative arteriographic examination. Conclusions: Due to the need for good mobilization, arterial ligations should be adjusted and modified depending on the particular vascular distribution, to maintain a sufficient blood flow in the marginal artery, in order to reach the colic sections and the straight arteries near them. Abbreviations: SMA -superior mesenteric artery; IMAinferior mesenteric artery; ICa -ileocolic artery; RCa -right colic artery; MCa -middle colic artery; LCa -left colic artery; LC acc.a -left accessory colic artery (or middle left colic artery); ILCa -inferior left colic artery; S trunk -sigmoidian trunk; Sa -sigmoidian artery; SRa -superior rectal arter

New Evidences on the Process Sensitivity of Some Renewable Blends Based on Starch considering Their Melt Rheological Properties

The degradability and processability of new renewable materials based on starch and PVOH were studied using the melt flow index (MFI) method by measuring the melt rheological properties which depend not only on the extrusion conditions and material formulation but also on the macromolecule characteristics which can be modified by chemical degradation. These results were correlated with other material properties like color and cross-linking degree. The obtained results show that flowing in the melted state of the studied materials is accompanied by a second process of chains chemical degradation. It was observed that, at the same level of additivation, under identical extrusion conditions, the melted blends with corn starch as main component are highly mechanically sensitive and degrade mostly by chains scission and those with PVOH as major component are highly temperature sensitive and degrade mainly by cross-linking. The obtained results show also that each PVOH-starch blend requires particular formulation and individual windows of melt processing conditions. These results are a good proof that the MFI method is a good path to study the degradability and moldability of process sensitive polymeric materials like those based on starch and PVOH

Extractive Fermentation of Lactic Acid in Lactic Acid Bacteria Cultivation:A Review

Lactic acid bacteria are industrially important microorganisms recognized for their fermentative ability mostly in their probiotic benefits as well as lactic acid production for various applications. Nevertheless, lactic acid fermentation often suffers end-product inhibition which decreases the cell growth rate. The inhibition of lactic acid is due to the solubility of the undissociated lactic acid within the cytoplasmic membrane and insolubility of dissociated lactate, which causes acidification of cytoplasm and failure of proton motive forces. This phenomenon influences the transmembrane pH gradient and decreases the amount of energy available for cell growth. In general, the restriction imposed by lactic acid on its fermentation can be avoided by extractive fermentation techniques, which can also be exploited for product recovery