Fracture of drilling head pipe connection due to quenching of heat affected zone (HAZ)

The drilling head pipe connection is made of quenched and tempered steel 34CrNiMo6. The steel characteristic is high hardenability. Due to unsuitable and untested welding technology the heat affected zone (HAZ) cooling rate after welding surpassed the upper critical cooling rate. During horizontal drilling of the rock, the resulting brittle martensite could not bear the dynamic loads which led to a brittle fracture of the pipe connection

Identification of deep trap levels from thermally stimulated current spectra of semi-insulating CdZnTe detector material

Deep trap levels in the semi-insulating (SI) CdZnTe detector material were characterized by simultaneous multiple peak analysis based on thermally stimulated current (TSC) measurements. In our TSCs that have been published previously electron hole pairs were created through the use of proton beam irradiation. Charge carriers were captured in deep traps and afterward released by thermal emission, which was recorded in the 90–300 K range. We showed that the obtained TSC spectra could be well fitted with a unique set of 14 different deep traps, which were all simultaneously and completely characterized. The obtained trap data are in good accordance with earlier deep trap characterizations of the other authors obtained on similar SI CdZnTe materials using different methods

Effect of nonmetallic inclusions on steel welds metal hot cracking

Intercrystally distributed nonmetallic inclusions greatly increase weld susceptibility to hot cracking. Oxide and sulphide inclusions are the result of contaminated base material or its highly oxidised surfaces and they can be a consequence of metallurgical reactions between welding slag and remelted base material, while carbide inclusions can occur due to the mixing of high-carbon base and low-carbon filler material. All welding surfaces must thus be cleaned before welding and the least possible mixture of base with filler material must be enusured during welding

Development of banded microstructure in 34CrNiMo6 steel

In this paper the development of a banded microstructure in hot-rolled 34CrNiMo6 steel which consisted of bainitic and martensitic bands is explained. The chemical compositions of the bands were measured with energy dispersive x-ray spectroscopy (EDS), which showed that the martensitic bands contained more alloying elements (Mn, Cr, Mo, Si) than bainitic bands. By using Oberhoffer reagent, the segregations of phosphorus were also revealed. These phosphorus segregations coincided with the positive segregations of the alloying elements. The continuous cooling transformation (CCT) diagrams of steel were calculated. They confirmed the formation of martensite in positive segregations and the formation of bainite in negative segregations

Structural and thermodynamic analysis of whiskers on the surface of grey cast iron

The paper focuses, first, on the characterization of the whiskers on the surface of grey cast iron and second, it gives an explanation of whiskers growth based on thermodynamic calculations. The whiskers were observed on the surface of hot plates for the electric stove after black-oxide-coating (blackening) performed the furnace at 650°C in order to produce a protective layer mainly of magnetite (Fe3O4). However, the whiskers caused brown spots on dark grey surface and thus, the surface was aesthetically damaged. The investigations confirmed that whiskers are of hematite (Fe2O3); however, the thermodynamic calculations present that hematite may be formed as a result of the oxidation of magnetite if the partial pressure of oxygen is increased during the blackening

Dvojni lijekovi primakina i nesteroidnih protuupalnih lijekova: Sinteza, hvatanje slobodnih radikala, antioksidativno djelovanje i keliranje Fe2+ iona

Novel primaquine conjugates with non-steroidal anti-inflammatory drugs (PQ-NSAIDs, 4a-h) were prepared, fully chemically characterized and screened for radical scavenging and antioxidant activities. The synthetic procedure leading to twin drugs 4a-h involved two steps: i) preparation of NSAID benzotriazolides 3a-h from the corresponding NSAID (ibuprofen, ketoprofen, fenoprofen, ketoprofen hydroxy and methylene analogues, diclofenac or indomethacin) and benzotriazole carboxylic acid chloride (BtCOCl, 1), ii) reaction of intermediates 3a-h with PQ. The prepared PQ-NSAIDs exerted moderate activities in the DPPH free radical test and -carotene-linoleic acid assay. Moreover, ketoprofen derivatives 4d and 4b demonstrated a notable Fe2+ chelating ability as well. On the other hand, negligible antiproliferative and antituberculotic effects of conjugates 4a-h were observed.U radu je opisana sinteza novih konjugata primakina s nesteroidnim protuupalnim lijekovima (PQ-NSAIDs, 4a-h), njihova potpuna karakterizacija te testiranje sposobnosti hvatanja slobodnih radikala i antioksidativnog djelovanja. Sintetski postupak za pripravu dvojnih lijekova 4a-h uključuje dva koraka: i) pripravu NSAID-benzotriazolida 3a-h iz odgovarajućih nesteroidnih protuupalnih lijekova (ibuprofena, ketoprofena, fenoprofena, hidroksi i metilenskih analoga ketoprofena, diklofenaka i indometacina) i klorida 1-benzotriazol karboksilne kiseline (BtCOCl, 1), ii) reakciju intermedijera 3a-h s primakinom. Novi PQ-NSAID konjugati pokazuju umjerenu sposobnost hvatanja slobodnih radikala u DPPH testu te umjereno antioksidativno djelovanje u pokusu s -karotenom i linoleinskom kiselinom. Osim toga, derivati ketoprofena 4d i 4b imaju primjetnu sposobnost keliranja Fe2+ iona. Svi konjugati 4a-h pokazuju vrlo slabo antiproliferativno i antituberkulotsko djelovanje

Structural and thermodynamic analysis of whiskers on the surface of grey cast iron

The paper focuses, first, on the characterization of the whiskers on the surface of grey cast iron and second, it gives an explanation of whiskers growth based on thermodynamic calculations. The whiskers were observed on the surface of hot plates for the electric stove after black-oxide-coating (blackening) performed the furnace at 650°C in order to produce a protective layer mainly of magnetite (Fe3O4). However, the whiskers caused brown spots on dark grey surface and thus, the surface was aesthetically damaged. The investigations confirmed that whiskers are of hematite (Fe2O3); however, the thermodynamic calculations present that hematite may be formed as a result of the oxidation of magnetite if the partial pressure of oxygen is increased during the blackening

Leukocyte counts in urine reflect the risk of concomitant sepsis in bacteriuric infants: A retrospective cohort study

<p>Abstract</p> <p>Background</p> <p>When urine infections are missed in febrile young infants with normal urinalysis, clinicians may worry about the risk – hitherto unverified – of concomitant invasion of blood and cerebrospinal fluid by uropathogens. In this study, we determine the extent of this risk.</p> <p>Methods</p> <p>In a retrospective cohort study of febrile 0–89 day old infants evaluated for sepsis in an urban academic pediatric emergency department (1993–1999), we estimated rates of bacteriuric sepsis (urinary tract infections complicated by sepsis) after stratifying infants by urine leukocyte counts higher, or lower than 10 cells/hpf. We compared the global accuracy of leukocytes in urine, leukocytes in peripheral blood, body temperature, and age for predicting bacteruric sepsis. The global accuracy of each test was estimated by calculating the area under its receiver operating characteristic curve (AUC). Chi-square and Fisher exact tests compared count data. Medians for data not normally distributed were compared by the Kruskal-Wallis test.</p> <p>Results</p> <p>Two thousand two hundred forty-nine young infants had a normal screening dipstick. None of these developed bacteremia or meningitis despite positive urine culture in 41 (1.8%). Of 1516 additional urine specimens sent for formal urinalysis, 1279 had 0–9 leukocytes/hpf. Urine pathogens were isolated less commonly (6% vs. 76%) and at lower concentrations in infants with few, compared to many urine leukocytes. Urine leukocytes (AUC: 0.94) were the most accurate predictors of bacteruric sepsis. Infants with urinary leukocytes < 10 cells/hpf were significantly less likely (0%; CI:0–0.3%) than those with higher leukocyte counts (5%; CI:2.6–8.7%) to have urinary tract infections complicated by bacteremia (N = 11) or bacterial meningitis (N = 1) – relative risk, 0 (CI:0–0.06) [RR, 0 (CI: 0–0.02), when including infants with negative dipstick]. Bands in peripheral blood had modest value for detecting bacteriuric sepsis (AUC: 0.78). Cases of sepsis without concomitant bacteriuria were comparatively rare (0.8%) and equally common in febrile young infants with low and high concentrations of urine leukocytes.</p> <p>Conclusion</p> <p>In young infants evaluated for fever, leukocytes in urine reflect the likelihood of bacteriuric sepsis. Infants with urinary tract infections missed because of few leukocytes in urine are at relatively low risk of invasive bacterial sepsis by pathogens isolated from urine.</p

Discordant antibiotic therapy and length of stay in children hospitalized for urinary tract infection

BACKGROUND: Urinary tract infections (UTIs) are a common reason for pediatric hospitalizations. OBJECTIVE: To determine the effect of discordant antibiotic therapy (in vitro nonsusceptibility of the uropathogen to initial antibiotic) on clinical outcomes for children hospitalized for UTI. DESIGN/SETTING: Multicenter retrospective cohort study in children aged 3 days to 18 years, hospitalized at 5 children's hospitals with a laboratory‐confirmed UTI. Data were obtained from medical records and the Pediatric Hospital Information System (PHIS) database. PARTICIPANTS: Patients with laboratory‐confirmed UTI. MAIN EXPOSURE: Discordant antibiotic therapy. MEASUREMENTS: Length of stay and fever duration. Covariates included age, sex, insurance, race, vesicoureteral reflux, antibiotic prophylaxis, genitourinary abnormality, and chronic care conditions. RESULTS: The median age of the 216 patients was 2.46 years (interquartile range [IQR]: 0.27, 8.89) and 25% were male. The most common causative organisms were E. coli and Klebsiella species. Discordant therapy occurred in 10% of cases and most commonly in cultures positive for Klebsiella species, Enterobacter species, and mixed organisms. In adjusted analyses, discordant therapy was associated with a 1.8 day (95% confidence interval [CI]: 1.5, 2.1) longer length of stay [LOS], but not with fever duration. CONCLUSIONS: Discordant antibiotic therapy for UTI is common and associated with longer hospitalizations. Further research is needed to understand the clinical factors contributing to the increased LOS and to inform decisions for empiric antibiotic selection in children with UTIs. Journal of Hospital Medicine 2012; © 2012 Society of Hospital MedicinePeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94298/1/1960_ftp.pd