bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxidative degradation of chemical warfare agents in water by bleaching powder
Authors: Qi Lihong , Zuo Guomin , Cheng Zhenxing , Zhu Haiyan , Li Shanmao
Published: August 2012

Degradation of sulfur mustard (HD), S-2-(di-isopropylamino)ethyl O-ethyl methylphosphonothioate (VX) and Soman (GD) in water by bleaching powder was investigated. The degradation products were comprehensively analyzed by gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS) and ion chromatography. Degradation pathways were deduced based on the identified products. The product analysis results indicated that HD could be degraded through oxidation and chlorination reactions, and a small portion of sulfur atoms could be mineralized into SO42− ion. Oxidative degradation of VX could finally generate O-ethyl methylphosphonate acid (EMPA), sulfonic acids, SO42− and NO3− ions. GD would be converted into non-toxic pinacolyl methylphosphonate via nucleophilic substitution.
Comparison of extracellular polymeric substances (EPS) extraction from two different activated sludges
Authors: Zhang Leiyan , Ren Hongqiang , Ding Lili
Published: August 2012

The characteristics of extracellular polymeric substances (EPS) extracted with five different extraction protocols from two different activated sludges were studied. The results showed that the major EPS constituent extracted by centrifugation was protein for the sludge in sequencing batch reactor treating chemical wastewater, and nucleic acid for the sludge in moving bed biofilm reactor treating synthetic urban wastewater. The order of EPS extraction amounting from the two sludges was formaldehyde + NaOH > formaldehyde + heating > EDTA > heating > centrifugation. The different extraction methods, the wastewater type, and activated sludge source greatly affected the amount and composition of EPS. The chemical extracted methods were more effective than the physical methods in extracting EPS for the two sludges. Moreover, formaldehyde combined NaOH was most effective in extracting EPS for the two sludges. However, chemical extraction could contaminate the EPS solution, which was pointed out by infra-red analysis and was also proved by cell lyses during EPS extraction and carrying over of the chemical extractant. Therefore, this study highlights that the choice of EPS extraction method should consider both the extraction yield and content and the contamination of extracting reagents to the EPS solution. The extraction procedures should be optimized and most effective.
Methodological challenges in evaluating performance, impact and ranking of IWRM strategies in the Jordan Valley
Authors: Wolff H. P. , Wolf L. , Subah A. , Guttman J. , Tamimi A. , Jarrar A. , Salman A. , Karablieh E.
Published: August 2012

The philosophy of integrated water resource management (IWRM), as formulated in several international summits, yielded numerous interpretations and extensions over the last decade but always focused on the overall objective of maximizing the welfare and livelihood of the people concerned. One of the major constraints of this concept is the gap between the well-defined philosophy and the fuzzy definition of operational and testable indicators for the achievement of its goals. This leads to difficulties in the evaluation of potential contributions from technological and managerial improvements. The experience of the multi-lateral IWRM research initiative SMART in the lower Jordan Valley shows that the evaluation and ranking of alternative IWRM strategies and their elements relies simultaneously on the identification of local goals and their interfaces with the superordinate national water sector policies. The documentation of the, still ongoing, development process of suitable assessment procedures describes their methodological embedding and conclusions drawn for the heterogeneous situation of water-related settings in this transboundary watershed.
Is a sequencing batch biofilter granular reactor suitable for textile wastewater treatment?
Authors: Lotito A. M. , Fratino U. , Mancini A. , Bergna G. , Di Iaconi C.
Published: August 2012

The textile industry releases highly polluted and complex wastewaters, which are difficult to treat and require numerous treatment steps. Innovative technologies for on-site treatment at each factory would permit cost reduction. For this reason, we ran a laboratory-scale study to assess the suitability of a sequencing batch biofilter granular reactor (SBBGR) for textile wastewater treatment, testing four different types of wastewater. Results demonstrate that wastewater characteristics greatly affect the reactor efficiency. Hence, a pre-study is advisable to define the best operational conditions and the maximum treatment capability for the wastewater under analysis. Nevertheless, SBBGR is a valuable biological treatment, effective in the reduction of pollutant load with stable performances despite the variability in wastewater composition. Tests with ozone integration have demonstrated that it is possible to dose small quantities of ozone to obtain an effluent suitable for direct discharge. However, a dynamic ozone dosage should be used to optimize the process as the correct ozone dose strongly depends on the wastewater composition.
Acid Black 48 dye biosorption using Saccharomyces cerevisiae immobilized with treated sugarcane bagasse
Authors: Mitter E. K. , Corso C. R.
Published: August 2012

The textile industry consumes large quantities of water and chemicals, especially in dyeing and finishing processes. Textile dye adsorption can be accomplished with natural or synthetic compounds. Cell immobilization using biomaterials allows the reduction of toxicity and mechanical resistance and opens spaces within the matrix for cell growth. The use of natural materials, such as sugarcane bagasse, is promising due to the low costs involved. The aim of the present study was to evaluate the use of sugarcane bagasse treated with either polyethyleneimine (PEI), NaOH or distilled water in the cell immobilization of Saccharomyces cerevisiae for textile dye removal. Three different adsorption tests were conducted: treated sugarcane bagasse alone, free yeast cells and bagasse-immobilized yeast cells. Yeast immobilization was 31.34% with PEI-treated bagasse, 8.56% with distilled water and 22.54% with NaOH. PEI-treated bagasse exhibited the best removal rates of the dye at all pH values studied (2.50, 4.50 and 6.50). The best Acid Black 48 adsorption rates were obtained with use of free yeast cells. At pH 2.50, 1 mg of free yeast cells was able to remove 5488.49 g of the dye. The lowest adsorption capacity rates were obtained using treated bagasse alone. However, the use of bagasse-immobilized cells increased adsorption efficiency from 20 to 40%. The use of immobilized cells in textile dye removal is very attractive due to adsorbed dye precipitation, which eliminates the industrial need for centrifugation processes. Dye adsorption using only yeast cells or sugarcane bagasse requires separation methods.
On a QSAR approach for the prediction of priority compound degradation by water treatment processes
Authors: Wols B. A. , Vries D.
Published: August 2012

Emerging (chemical) substances are increasingly found in water sources and must be removed by water treatment systems. However, the treatment efficiency regarding these substances is often unknown. A promising approach is using QSARs (quantitative structure activity relationships) or QSPRs (quantitative structure property relationships) to correlate the existing knowledge of a compound's chemical structure to water treatment process properties, such as a biological activity or physico-chemical property. As UV/H2O2 treatment of water is an important barrier against priority pollutants, a QSAR model has been developed for the prediction of a typical physico-chemical property: i.e. hydroxyl radical reaction constants. Hydroxyl radicals are highly reactive and therefore largely responsible for a compound's degradation during UV/H2O2 treatment. A good correlation is found for the training data set. Chemical parameters that were related to charge on C atoms and topology of the compound were found to be important for the hydroxyl radical rate constants. So far, these results look promising, but further research is still required to increase the predictability of the model and to develop QSAR models for other physico-chemical properties.
Inhibition effect of swine wastewater heavy metals and antibiotics on anammox activity
Authors: Lotti T. , Cordola M. , Kleerebezem R. , Caffaz S. , Lubello C. , van Loosdrecht M. C. M.
Published: August 2012

The feasibility of anaerobic ammonium oxidation (anammox) process to treat wastewaters containing antibiotics and heavy metals (such as the liquid fraction of the anaerobically digested swine manure) was studied in this work. The specific anammox activity (SAA) was evaluated by means of manometric batch tests. The effects of oxytetracycline, sulfathiazole, copper and zinc were studied. The experimental data of the short-term assays were fitted with an inhibition model to identify the half maximal inhibitory concentration (IC50). After 24 h exposures, IC50-values equal to 1.9, 3.9, 650 and 1,100 mg L−1 were identified for copper, zinc, sulfathiazole and tetracycline respectively. The effect of prolonged exposure (14 days) to oxytetracycline and sulfathiazole was studied by means of repeated batch-assays. Anabolism and catabolism reactions were active during the inhibition tests indicating that anammox bacteria could grow even in the extreme conditions tested. Considering the average concentrations expected in swine wastewaters, the inhibitors studied do not seem to represent a problem for the application of the anammox process. However, in order to verify the effect of these compounds on the growth of anammox bacteria, continuous culture experiments could be conducted.
Settlement as a driver for sewer rehabilitation
Authors: Dirksen J. , Baars E. J. , Langeveld J. G. , Clemens F. H. L. R.
Published: August 2012

This paper assesses the influence of (differential) settlement on sewer system functioning. Based on historical data of the vertical position of sewer invert levels, tilt measurements and in-sewer inspection videos, settlement and settlement related influences are analyzed for a case study area in Amsterdam. The average settlement rate of this system was 4 mm/year. Given this settlement rate, it is shown that settlement significantly influences sewer system functioning within the lifetime of a sewer (system).
Microbial community structure and performance of an anaerobic reactor digesting cassava pulp and pig manure
Authors: Panichnumsin P. , Ahring B. , Nopharatana A. , Chaiprasert P.
Published: August 2012

Microbial community dynamics in response to changes in substrate types (i.e. pig manure (PM), cassava pulp (CP) and mixtures of PM and CP) were investigated in an anaerobic continuously stirred tank reactor (CSTR). Molecular identification of bacterial and archaeal domains were performed, using a 16S rDNA clone library with polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) screening and phylogenetic analysis. Analysis of bacterial clone libraries revealed that the differences in the community structure corresponded to the substrate types. However, the Bacteroidetes were the most abundant group in all substrates, followed by the Clostridia. With pure PM, the dominant bacterial groups were Bacteroidales, Clostridia and Paludibacter. With a co-substrate, at CP to PM (CP:PM) ratio of 50:50, the sequences analysis revealed the greatest diversity of bacterial communities at class level, and the sequences affiliated with Cytophaga sp. became an exclusive predominant. With CP alone, Bacteroides sp. was the dominant species and this reactor had the lowest diversity of bacteria. Archaea observed in the CSTR fed with all substrate types were Methanosaeta sp., Methanosaeta concilii and Methanospirillum hungatei. Among the Archaea, Methanosaeta sp. was the exclusive predominant. The relative distribution of Archaea also changed regarding to the substrate types.
Numerical modelling of odour dispersion around a cubical obstacle using large eddy simulation
Authors: Dourado Harerton Oliveira , Santos Jane Meri , Reis Neyval C. , Mavroidis Ilias
Published: August 2012

In the present work two different large eddy simulation (LES) approaches, namely the Dynamic Smagorinsky model and the Wale model, are used to simulate the air flow and pollutant dispersion around a cubical obstacle. Results are compared with wind tunnel data (WT) and with results from the Smagorinsky LES model. Overall agreement was good between the different LES approaches and the WT results, both for the mean and fluctuating flow and concentration patterns. LES models can provide good estimates of concentration fluctuation intensity and enable the calculation of the intermittency factor. The model results indicate that LES is a viable tool for odour impact assessment.
Anterior Cruciate Ligament Graft Choices: A Review of Current Concepts
Authors: Dheerendra Sujay K , Khan Wasim S , Singhal Rohit , Shivarathre Deepak G , Pydisetty Ravi , Johnstone David
Published: August 2012

The graft choice for anterior cruciate ligament (ACL) reconstruction continues to be controversial. There are several options available for the treating surgeon, including Bone Patellar Tendon Bone (BPTB) grafts, Hamstring tendon (HT) grafts, allografts and synthetic grafts. Within the last decade there have been several comparative trials and meta-analysis, which have failed to provide an answer with regards to the best graft available. The aim of this review is to understand the current concepts in graft choices for ACL reconstruction.
Recent Advances and Developments in Knee Surgery: Principles of Periprosthetic Knee Fracture Management
Authors: Chimutengwende-Gordon Mukai , Khan Wasim , Johnstone David
Published: August 2012

The management of distal femoral, tibial and patellar fractures after total knee arthroplasty can be complex. The incidence of these fractures is increasing as the number of total knee arthroplasties being performed and patient longevity is increasing. There is a wide range of treatment options including revision arthroplasty for loose implants. This review article discusses the epidemiology, risk factors, classification and treatment of these fractures.
Friedrich von Esmarch: Surgeon, one career
Authors: Bumbasirevic Marko , Zagorac Slavisa , Manojlovic Radovan , Djurasic Ljubomir , Lesic Aleksandar
Published: August 2012

Friedrich von Esmarch was born in 1823 in Germany and he is one of the
greatest surgeons of the Germany of that time. Fridrich von Esmarch
introduced the Esmarch tourniquet, which enables operative field bloodless.
This revolutionary innovation is still present in the orthopaedic surgery all
around world, as well as for the first line hemostasis. Beside this, Esmarch
also improves others fields of surgery: immobilizations, methods of
antiseptic surgery, modified Esmarch mask for anesthesia. He joined few wars
and had a rang surgeon-general. Although his experience was primary from the
trauma, he also introduced the training courses of the First aid for the
ordinary people, making medicine of that time more modern and efficient.
The results of treatment of primary brain tumors in children
Authors: Mrdak Milan , Mihajlovic Miljan , Nikolic Igor , Repac Nikola , Jovanovic Vladimir , Scepanovic Vuk , Janicijevic Aleksandar , Bogdanovic Ivan , Nestorovic Branislav , Tasic Goran
Published: August 2012

During the period of 2009-2011 in UCH in Belgrade, we treated 22 patients
with brain tumors. Treatment included the diagnosis and therapy that included
surgery and postoperative neuroradiological follow-up of all patients
regardless of whether radiotherapy was conducted with or without
chemotherapy. The most frequent were low grade astrocytomas and
medulloblastomas. Patients with supratentorial localization of tumor had
significantly smaller neurological sequelae compared with patients with
infratentorial as well as patients diagnosed with low grade astrocytomas of
any localization. From 10 patients with supratentorial localization,7 of them
had no neurological deficit, while from 11 patients with infratentorial
localization, 3 of them were without deficit. Patients with histological
diagnosis of low grade astrocytoma of any localization had less neurological
deficits compared with other tumors. From 7 low grade astrocytoma in 5 of
them there was no neurological deficit, while only in one patient residual
tumor was verified. In 7 patients the rest of the tumor was diagnosed, while
in 14 patients no residual tumors was diagnosed during follow-up based on the
MRI diagnosis. Surgery, postoperative radiotherapy and chemotherapy in some
cases represent an effective therapeutic approach in the treatment of brain
tumors in children.
Tumors of the horseshoe kidney: Characteristics and literature review
Authors: Petrovic Milan , Andrejevic Vladan , Djurasic Ljubomir , Stamenkovic Vladimir , Acimovic Miodrag , Pejcic Tomislav , Basic Dragoslav , Hadzi-Djokic Jovan
Published: August 2012

The aim of this paper is to point out the significance of the rare urinary
system anomaly such as horseshoe kidney. Tumors of the horseshoe kidney are
rarely described as single cases in literature. Bilateral tumors of the
horseshoe kidney can present a health and therapeutically challenge. In this
paper we have analyzed characteristics of the horse shoe kidney tumors and
their diagnostics. Primary means of the horseshoe kidney tumors treatment are
surgical with different techniques depending on the size, presentation of the
tumor and other indications. The review of the available literature is also
included.
Evaluation of comparative results of rehabilitation of patients with acromioclavicular dislocation of the third degree treated by surgical techniques by phemister and vukov
Authors: Radovanovic Tatjana , Vukov Vladimir , Bumbasirevic Marko , Manojlovic-Opacic Mirjana , Grajic Mirko , Djurasic Ljubomir
Published: August 2012

Introduction: In terms of access to treatment of acromioclavicular joint
injuries, there are many controversies, especially after the appearance of
works that promote "neglecting of injury". Goal: The aim of this paper is to
give a comparative analysis of the results of rehabilitation of patients
after acute injury of the acromioclavicular joint of the third degree,
treated by two surgical techniques: by Phemister and Vukov. Material and
methods: In this study, we investigated a total of 60 operated patients: 30
patients were operated by Phemister technique, and 30 by Vukov technique.
Results: Postoperative follow-up lasted for one year. Between these two
groups, the time when the rehabilitation process began is significantly
different p<0.01. With technique by Vukov, the rehabilitation begins on the
first postoperative day and with technique by Phemister it begins later
(after 7 weeks outpatient). With technique by Phemister, rehabilitation
lasted on average 60 days, and with technique by Vukov on average 40 days.
The duration of recovery is also significantly different p< 0.01, with
technique by Vukov the duration time is shorter, and therefore the process of
rehabilitation in days - is shorter than with the other technique. Both
techniques gave good stability of the lateral end of clavicle. The difference
was not statistically significant p> 0.05, which means that both techniques
can be applied depending on the indication and the experience of the surgeon.
"One step procedure" local anaesthesia for inguinal hernia repair in ambulatory surgery conditions: District general hospital experience
Authors: Dabic Dejan , Perunicic Vladan , Maric Biljana
Published: August 2012

Ambulatory surgery refers to hospitalization that does not exceed 24 hours,
during which a surgical procedure is performed. Inguinal hernia repairs done
under local anaesthesia on an outpatient basis are no longer performed
exclusively in specialized hernia centers. They are becoming widely accepted
by surgeons working in district hospitals, which was significantly
contributed to by the publication of the EHS Guidelines on the Treatment of
Inguinal Hernia. OBJECTIVE: The objective of this retrospective study is to
show local anaesthesia practicability for inguinal hernia repairs through
"one-step procedure", being a one-day procedure used in District General
Hospital. METHODS: From January 2006 to June 2011, 460 elective surgery
procedures were performed on 428 patients with inguinal hernia (396 with
unilateral and 32 with bilateral inguinal hernia), using Lichtenstein
technique, UHS/PHS, plug repair, and Shouldice technique. All the proceduress
were performed under local anaesthesia by the same surgeon using "one-step
procedure" in ambulatory surgery. The following anaesthetics were used:
Lidocaine for intradermal and subcutaneous anaesthesia as well as
Bupivacaine/Levobupivacaine for subfascial anaesthesia. RESULTS: From January
2006 to June 2011, 460 surgical procedures were performed on 428 patients
with inguinal hernia (396 with unilateral and 32 with bilateral inguinal
hernia). The mean age was 58.2 yrs (20-84). All the patients were in the ASA
I - III group. In unilateral hernias, the mean operating time using
Lichtenstein technique was 38mins (28-56), using PHS/UHS 28mins (22-40), with
plug 33mins (27- 39) and using Shouldice technique 43mins (32-53). In
bilateral hernias, the mean operating time using Lichtenstein technique was
71mis (56-87), and using PHS /UHS 56mins (49-64). The mean hospital stay was
2.9hrs (2-6). The mean distance of residence from the hospital was 23km
(1-150). During the course of the surgery, 15 patients (3.5%) had problems
such as pain, bradycardia, hypotension, or perspiration. The complications
during the mean follow-up of 31 months (1-60) was: 1.4% (6 patients) - a
hematoma, 1.87% (8 patients) - seroma, 0.47% (2 patients) - wound infection,
0.23% (1 patient) - chronic pain, and 0.47% (2 patients) - recurrence.
Revision due to active bleeding was conducted in two patients (0.47%), after
using PHS and Lichtenstein techniques. These were the only patients who were
rehospitalized due to complications. CONCLUSION: In hernia repairs on an
outpatient basis, "one-step procedure" in local anaesthetic administration is
reliable, easy, safe, effective, and the type of the surgical technique is
not a determining factor. The success rate and treatment outcome depend on
the surgical technique and the surgeon?s experience in using local
anaesthesia in ambulatory surgery.
Unusual eye injuries
Authors: Jovanovic Milos , Bobic-Radovanovic Anica , Vukovic Dragan , Markovic Vujica
Published: August 2012

Purpose: The analysis of ten unusual eye injuries, and the discussion of
appropriate preventive measures. Case outline: Ten patients hospitalized at
the Clinic of Eye Diseases, Clinical Center of Serbia, Belgrade, in the
period from January 2000. to December 2009. were presented. Following data
were taken in account: sex and age of the patient, injured eye, the mechanism
of injury, type of the injury, applied treatment and final visual acuity. The
circumstances of the eye injuring of ten patients were described. The eye
injuries in all cases occurred in a bizarre way and they were severe enough
to require hospital admission. The surgery was necessary in seven patients.
Three injured eyes resulted in blindness, and two additional had subnormal
vision. Conclusion: In three quarters of discussed cases injuries can be
avoided. It is necessary to implement protective measures constantly and
consistently and to think about the possible consequences of certain
activities. Particular attention should be paid on safety of children. The
iatrogenic injuries require special consideration.
Multiple port-site metastasis of incidental gallbladder carcinoma after laparoscopic cholecystectomy
Authors: Raznatovic Zoran , Zaric Nemanja , Galun Danijel , Lekic Nebojsa , Micev Marjan , Djordjevic Vladimir , Djurasic Ljubomir , Kerkez Mirko
Published: August 2012

Laparoscopic cholecystectomy is a surgical procedure of choice for benign
gallbladder diseases. In about 1-2% of cases histopathological examination
demonstrate incidental gallbladder cancer (GBCA). We report a case of a 61
year old woman who developed port site metastases after laparoscopic
cholecystectomy for adenocarcinoma of the gallbladder. Metastases appeared on
all four port sites. Review of literature regarding incidental GBCA an port
site metastases was also performed. We conclude that the retrieval bag should
be routinely used in laparoscopic cholecystectomy; the procedure should be
performed with minimal trauma; in cases of incidental GB carcinoma, full
thickness excision of the abdominal wall of the port sites demands additional
studies; additional liver bed excision and local lymphadenectomy for T1b
carcinoma are yet to be considered.
Adnexal torsion during puerperium as a complication of delayed surgical treatment of ovarian tumor in pregnancy
Authors: Sparic Radmila , Buzadzic Snezana , Argirovic Rajka , Opalic Jasna
Published: August 2012

Ovarian tumors in pregnancy represent a significant issue both in terms of
diagnostics and therapy. Increased use of the ultrasound in pregnancy in the
last several decades has contributed to the rise in the number of diagnosed
asymptomatic adnexal tumors with pregnant women. We present a case of a
patient treated in our clinic for asymptomatic ovarian tumor, which was
diagnosed in pregnancy. The patient underwent check-ups every four weeks,
comprising clinical and sonographical examinations and relevant laboratory
and tumor marker tests. The course of pregnancy was normal, with no detected
tumor growth and with the tumor marker levels within the reference range.
Following an uneventful delivery, she developed abdominal pains during the
puerperium, and the adnexal torsion was diagnosed intraoperatively. The
attitudes to treating of adnexal tumors in pregnancy are controversial, and
there exist no defined treatment protocols. It is, therefore, necessary to
make an individual evaluation of each case, and the relevant decisions should
be made with the pregnant woman?s informed consent. The adnexal torsion in
the presented case can be explained by the size of the tumor as well as the
progressive reduction of the size of the uterus due to the physical
involution during puerperium.
Synthesis of 2-azetidinones substituted quinoline derivative
Authors: Mashelkar Uday , Jha Mukesh , Mashelkar Beena
Published: August 2012

Acetanilide is converted into 2-chloro-3-formyl quinoline by reacting with
DMF-POCl3 at 80-90?C and then condensed with aromatic primary amines to give
Schiff bases (3a-3c). These Schiff bases are then reacted with acid chlorides
in the presence of base in toluene to give 1, 3, 4-substituted
2-azetidinones.
Surgical treatment modality for facial esthetics in an obstructive sleep apnea patient with protrusive upper lip and acute nasolabial angle
Authors: Ahn Hyo-Won , Cho Il-Sik , Cho Keun-Chul , Choi Jin-Young , Chung Jin-Woo , Baek Seung-Hak
Published: August 2012

For patients with severe obstructive sleep apnea syndrome (OSAS), maxillomandibular advancement (MMA) offers a good treatment option by physically expanding the skeletal framework. However, facial esthetics can be aggravated by MMA in patients with OSAS who have a normally positioned maxilla, a protrusive upper lip, and an acute nasolabial angle. Therefore, surgical treatment planning should be customized according to diverse skeletodental and soft-tissue patterns to produce a favorable change in facial esthetics and sleep function in patients with OSAS. In this case report, good treatment results were achieved in a young female patient with OSAS and skeletal Class II, a normally positioned maxilla, a protrusive upper lip, and acute nasolabial angle by impaction of the maxilla, autorotation/advancement of the mandible, and advancement of the chin. A customized flowchart for surgical treatment planning in OSAS that considers facial esthetics was suggested.
On local convexity of nonlinear mappings between Banach spaces
Authors: Banakh Iryna , Banakh Taras , Plichko Anatolij , Prykarpatsky Anatoliy
Published: August 2012

We find conditions for a smooth nonlinear map f: U → V between open subsets of Hilbert or Banach spaces to be locally convex in the sense that for some c and each positive ɛ < c the image f(B
ɛ(x)) of each ɛ-ball B
ɛ(x) ⊂ U is convex. We give a lower bound on c via the second order Lipschitz constant Lip2(f), the Lipschitz-open constant Lipo(f) of f, and the 2-convexity number conv2(X) of the Banach space X.
Delamination of impacted composite structures by cohesive zone interface elements and tiebreak contact
Authors: Dogan Fatih , Hadavinia Homayoun , Donchev Todor , Bhonge Prasannakumar
Published: August 2012

Maximising impact protection of fibre reinforced plastic (FRP) laminated composite structures and predicting and preventing the negative effects of impact on these structures are paramount design criteria for ground and space vehicles. In this paper the low velocity impact response of these structures will be investigated. The current work is based on the application of explicit finite element software for modelling the behaviour of laminated composite plates under low velocity impact loading and it explores the impact, post impact and failure of these structures. Three models, namely thick shell elements with cohesive interface, solid elements with cohesive interface, and thin shell elements with tiebreak contact, were all developed in the explicit nonlinear finite element code LS-DYNA. The FEA results in terms of force and energy are validated with experimental studies in the literature. The numerical results are utilized in providing guidelines for modelling and impact simulation of FRP laminated composites, and recommendations are provided in terms of modelling and simulation parameters such as element size, number of shell sub-laminates, and contact stiffness scale factors.
Modelling and simulation of explosions in soil interacting with deformable structures
Authors: Zakrisson Björn , Häggblad Hans-Áke , Jonsén Pär
Published: August 2012

A detonating explosive interacting with a deformable structure is a highly transient and non-linear event. In field blast trials of military vehicles, a standard procedure is often followed in order to reduce the uncertainties and increase the quality of the test. If the explosive is buried in the ground, the state of the soil must meet specific demands. In the present work, laboratory experiments have been performed to characterize the behaviour of a soil material. Soil may be considered a three-phase medium, consisting of solid grains, water and air. Variations between the amounts of these phases affect the mechanical properties of the soil. The experimental outcome has formed input data to represent the soil behaviour included in a three-phase elastic-plastic cap model. This unified constitutive model for soil has been used for numerical simulations representing field blast trials, where the explosive load is interacting with a deformable structure. The blast trials included explosive buried at different depths in wet or dry sand. A dependence of the soil initial conditions can be shown, both in the past field trials along with the numerical simulations. Even though some deviations exist, the simulations showed in general acceptable agreement with the experimental results.
Impact damage assessment by using peridynamic theory
Authors: Oterkus Erkan , Guven Ibrahim , Madenci Erdogan
Published: August 2012

This study presents an application of peridynamic theory for predicting residual strength of impact damaged building components by considering a reinforced panel subjected to multiple load paths. The validity of the approach is established first by simulating a controlled experiment resulting in mixed-mode fracture of concrete. The agreement between the PD prediction and the experimentally observed behavior is remarkable especially considering the simple material model used for the concrete. Subsequently, the PD simulation concerns damage assessment and residual strength of a reinforced panel under compression after impact due to a rigid penetrator.
An investigation on low-velocity impact response of elastomeric & crushable foams
Authors: Sadighi Mojtaba , Salami Sattar
Published: August 2012

The mechanical behavior of elastomeric foam, in particular, Ethylene Propylene Diene Methyle (EPDM) and crushable foams, in particular, Expanded Poly-Propylene (EPP) and Poly Urthane Rigid (PUR), under low-velocity impact are studied experimentally and numerically. At first, these foams were loaded under quasi-static loading in compression. In order to study the dependence of their behavior on strain rate, the loadings were performed in two rates, 3 mm/min and 100 mm/min. The low-velocity impact tests were applied using a drop hammer testing machine. The drop heights of projectile in all tests were 0.5 and 1 m. The thickness effect of specimens on absorption of energy and parameters such as, contact force and displacement of specimens are discussed. Then, the dynamic factors of force and energy for three types of foam are investigated. Since, EPP showed an insensitive property to the thickness of specimen in the impact tests, it is possible to define dynamic factors for different thickness of this type of foam. Finally, all test results are compared with numerical results through implementation of ABAQUS finite element package. Good agreements between numerical results and experimental data show the capability of numerical modeling to fulfill the experimental investigation.
Quantum Walks
Authors: Reitzner Daniel , Nagaj Daniel , Bužek Vladimír
Published: August 2012

Quantum Walks

This tutorial article showcases the many varieties and uses of
A Technique for Solving Special Type Quadratic Programming Problems
Authors: Hasan M. Babul
Published: August 2012

Because of its usefulness in production planning, financial and corporate planning, health care and hospital planning, quadratic programming (QP) problems have attracted considerable research and interest in recent years. In this paper, we first extend the simplex method for solving QP problems by replacing one basic variable at an iteration of simplex method. We then develop an algorithm and a computer technique for solving quadratic programming problem involving the product of two indefinite factorized linear functions. For developing the technique, we use programming language MATHEMATICA. We also illustrate numerical examples to demonstrate our technique.DOI: http://dx.doi.org/10.3329/dujs.v60i2.11520 Dhaka Univ. J. Sci. 60(2): 209-215, 2012 (July)
Exterior Algebra with Differential Forms on Manifolds
Authors: Ali Md. Showkat , Ahmed K.M. , Khan M.R. , Islam Md. Mirazul
Published: August 2012

The concept of an exterior algebra was originally introduced by H. Grassman for the purpose of studying linear spaces. Subsequently Elie Cartan developed the theory of exterior differentiation and successfully applied it to the study of differential geometry [8], [9] or differential equations. More recently, exterior algebra has become powerful and irreplaceable tools in the study of differential manifolds with differential forms and we develop theorems on exterior algebra with examples.DOI: http://dx.doi.org/10.3329/dujs.v60i2.11528 Dhaka Univ. J. Sci. 60(2): 247-252, 2012 (July)
Origin of the Larger Values of Total Cross Section for Helium Scattering from Isolated Atomic Steps
Authors: Sultana K.S. , Allison W. , Hafiz M.Z.
Published: August 2012

The effect of surface relaxation and the electronic re-arrangement in the vicinity of a step on the total step cross section for helium scattering is investigated. A realistic helium interaction potential at a Cu(001) step is modeled by summing non-spherical pair potentials which allows for the possibility of varying the smoothing across the surface due to the itinerant aspects of the surface electronic structure. Numerical calculations reveal a significant increase in the magnitude of the total step cross section with large charge re-arrangement in the vicinity of the step. Also, the relaxation of surface layers has no effect whatsoever. The present study clearly shows that the origin of the experimentally observed large step cross section is the hard wall scattering from charge re-arrangement in the proximity of the step. Further, the charge re-arrangements probed by thermal helium atoms must be greater than predicted by pairwise models.DOI: http://dx.doi.org/10.3329/dujs.v60i2.11532 Dhaka Univ. J. Sci. 60(2): 271-275, 2012 (July)
Impedance Analyses of Alumina-Molybdenum (Al2O3-Mo) Composites
Authors: Hussain S. , Sbaizero O.
Published: August 2012

The microstructure and electrical properties of Al2O3-Mo composites were investigated. Different amounts of molybdenum (5, 10, 20, 25 vol%) were added to alumina matrix and the resulting mixture was hot pressed to produce dense metal toughened-ceramic composites. The electrical properties of the composites were examined using impedance spectroscopy in the temperature range 250° C - 1000° C at 50° C temperature intervals. From the analysis, two readily resolvable arcs were found to be present: the one at higher frequencies is the intragranular (grain) response of the bulk; the other is the intergranular (grain boundary) response caused in the internal surfaces of polycrystalline specimens at low frequencies. The effects of grains and grain boundaries on the electrical properties of the composites vary with the composition and temperature. The temperature and composition dependence of grain and grain boundary conductivities are explained by the microstructure.DOI: http://dx.doi.org/10.3329/dujs.v60i2.11533 Dhaka Univ. J. Sci. 60(2): 277-281, 2012 (July)
Spatio-Temporal Trends of Oak Decline and Mortality under Periodic Regional Drought in the Ozark Highlands of Arkansas and Missouri
Authors: Fan Zhaofei , Fan Xiuli , Crosby Michael K. , Moser W. Keith , He Hong , Spetich Martin A. , Shifley Stephen R.
Published: August 2012

At the forest landscape/region level, based on annual Forest Inventory and Analysis plot data from 1999 to 2010, oak decline and mortality trends for major oak species (groups) were examined in the Ozark Highlands of Arkansas and Missouri. Oak decline has elevated cumulative mortality of red oak species to between 11 and 15 percent in terms of relative density and basal area of standing dead oak trees, respectively. These values are three to five times higher than for white oak group and non-oak species. Oak decline and associated escalating mortality have occurred primarily in red oak species while the white oak group has maintained a relatively stable mortality rate that is comparable to non-oak species. Cross-correlation analyses indicate that mortality in the red oak group was significantly correlated with the growing season Palmer drought severity index (PDSI) and usually lagged two to three years following single drought events. Moreover, based on the past 17 years PDSI data, it appears that the cumulative impacts of drought may last up to 10 years. The Ozark Highlands experienced a severe drought extending from 1998 to 2000 and another milder drought from 2005 to 2006. These drought events triggered the escalation of mortality starting around year 2000. Spatially, high red oak mortality sites (hot spots with proportional basal area mortality > 0.12) initially occurred in the central Ozarks and spread gradually over most of the Ozark Highlands as regional droughts continued. In contrast, sites with elevated white oak and non-oak mortality occurred sporadically, mainly in the southern portion (Arkansas) of the Ozark Highlands. During the most recent inventory period (2006–2010), over 60%, 7% and 5% of red oak, white oak and non-oak groups, respectively, had relative mortality rates of > 12%.
Saving Renaissance and Reformation: History, Grammar, and Disagreements with the Dead
Authors: Fasolt Constantin
Published: August 2012

Renaissance and Reformation used to serve historians as the main terms with which to refer to European history from roughly 1300–1600. Today those terms are commonly replaced with early modern history, and the periodization of European history into ancient, medieval, and modern periods itself is looking increasingly suspect. There are good reasons for those changes. But they obscure both the significance of disagreements dividing the living from the dead and the significance of grammar, in the fundamental sense of grammar advanced by Wittgenstein, for treating such disagreements. Renaissance and Reformation have the advantage of doing just the opposite: they confront us with both those disagreements and the significance of grammar. That makes them very much worth keeping.
The City of Man, European Émigrés, and the Genesis of Postwar Conservative Thought
Authors: Gordon Adi , Greenberg Udi
Published: August 2012

This article explores the forgotten manifesto The City of Man: A Declaration on World Democracy, which was composed in 1940 by a group of prominent American and European anti-isolationist intellectuals, including Thomas Mann, Reinhold Niebuhr, and Hermann Broch. Written in response to the victories of Nazi Germany, the manifesto declared that the United States had a new global responsibility not only to lead the war against fascism and Marxism, but also to establish a global order of peace and democracy under U.S. hegemony. Moreover, the authors of the manifesto claimed that such an order would have to be based on the rejuvenation of conservative values; in their view, the collapse of Western democracies under the weight of totalitarian aggression was the consequence of inner moral and intellectual degeneration. The City of Man therefore called on the United States to lead the spiritual transformation of democracy into a modern political religion, which would bring about the intellectual and political unity of humanity under one state and one creed. This article analyzes the manifesto as a rare window into the difficulty intellectuals faced as they tried to conceptualize the totalitarian challenge prior to the United States’ entry into the war. Moreover, it claims that The City of Man expressed the emergence of postwar conservatism and Cold War ideology, as well as the unique role played by European émigrés in this process.
Sensorial Systems Applied to Intelligent Spaces
Authors: Lázaro-Galilea José Luis , Bravo-Muñoz Ignacio , Gardel-Vicente Alfredo
Published: August 2012

The definition of “Intelligent Space” (IS) was formerly proposed for an environmental system capable of offering humans informative and physical support. Currently an IS denotes a space containing human and artificial systems, the space itself being considered an intelligent system. Human and artificial systems become clients of the IS and simultaneously the artificial systems become agents of the IS. Since the whole space is an intelligent system, it is able to monitor and provide services to many different clients with ease. For example, an IS uses electronic displays to provide information to humans, then robots are used to offer physical services to them as physical agents. [...]
Automatic Carbon Dioxide-Methane Gas Sensor Based on the Solubility of Gases in Water
Authors: Cadena-Pereda Raúl O. , Rivera-Muñoz Eric M. , Herrera-Ruiz Gilberto , Gomez-Melendez Domingo J. , Anaya-Rivera Ely K.
Published: August 2012

Biogas methane content is a relevant variable in anaerobic digestion processing where knowledge of process kinetics or an early indicator of digester failure is needed. The contribution of this work is the development of a novel, simple and low cost automatic carbon dioxide-methane gas sensor based on the solubility of gases in water as the precursor of a sensor for biogas quality monitoring. The device described in this work was used for determining the composition of binary mixtures, such as carbon dioxide-methane, in the range of 0–100%. The design and implementation of a digital signal processor and control system into a low-cost Field Programmable Gate Array (FPGA) platform has permitted the successful application of data acquisition, data distribution and digital data processing, making the construction of a standalone carbon dioxide-methane gas sensor possible.
A Linear, Millimetre Displacement-to-Frequency Transducer
Authors: Agee John T. , Petto Four K.
Published: August 2012

The paper presents a novel linear, high-fidelity millimetre displacement-to-frequency transducer, based on the resistive conversion of displacement into a proportional voltage, and then frequency. The derivation of the nonlinearity, fidelity and sensitivity of the transducer is presented. Experimental results confirm that a displacement of 0–100 mm is converted into a frequency range of 0–100 kHz, with a normalised fidelity factor of 99.91%, and a worst-case nonlinearity of less than 0.08%. Tests using laboratory standards show that a displacement of 10 mm is transduced with an accuracy of ±0.6%, and a standard deviation of 530 Hz. Estimates included in the paper show that the transducer could cost less than 1% of existing systems for millimeter displacement measurement.
Organocatalytic asymmetric allylic amination of Morita–Baylis–Hillman carbonates of isatins
Authors: Zhang Hang , Zhang Shan-Jun , Zhou Qing-Qing , Dong Lin , Chen Ying-Chun
Published: August 2012

The investigation of a Lewis base catalyzed asymmetric allylic amination of Morita–Baylis–Hillman carbonates derived from isatins afforded an electrophilic pathway to access multifunctional oxindoles bearing a C3-quaternary stereocenter, provided with good to excellent enantioselectivity (up to 94% ee) and in high yields (up to 97%).
Vertebral Osteonecrosis in An HIV-Infected Patient
Authors: Sifuentes Giraldo Walter A , Villa Cristina C Macía , Rodríguez-Navarro Carmen Quereda , Díaz Mónica Vázquez
Published: August 2012

Vertebral osteonecrosis, also known as Kümmell's disease, is a disorder resulting in non-consolidation of a vertebral fracture caused by ischaemia. The main differential diagnosis of vertebral osteonecrosis is osteoporotic vertebral fracture; however, the former is associated more frequently with severe pain and neurological complications. Although HIV-infected patients have an increased risk of developing osteonecrosis in peripheral locations and osteoporotic vertebral fractures, the occurrence of vertebral osteonecrosis has not been previously reported in any of the large series of HIV-associated osteonecrosis. Here, we report an HIV-infected patient who developed vertebral osteonecrosis with refractory pain and displayed rapid kyphotic deformity development during HAART.
Perioperative Management of Antiplatelet Agents
Authors: Mohr Tyler S. , Brouse Sara D.
Published: August 2012

Perioperative management of antiplatelet agents is a common challenge with the increased number of patients requiring long-term therapy following coronary stenting. Debate currently exists regarding if and when to discontinue antiplatelet therapy prior to elective surgery. The delicate balance between decreasing the risk of bleeding intraoperatively and minimizing the risk of stent thrombosis in patients who are already at a high thrombotic risk is a major concern. This article summarizes the information available for perioperative management of common antiplatelet agents, as well as antiplatelet agents in development.