bluuebunny/crossref_metadata_2025 huggingface dataset:
Engineering a Successful Sour, Heavy Oil Test in a Sensitive Offshore Environment in Saudi Arabia
Authors: Al-Nahdi AbdulHakim , Gill Harmohan , Farid Usman , Morris Ronald , Omidiya Abdur-Rasheed
Published: December 2011

Exploration for heavy oil, in an offshore setting carries special challenges and risks, especially during the well testing phase. Bringing the heavy oil to surface and then disposing of this oil efficiently without polluting the offshore environment is a challenge. Flow testing oil with APIs as low as 8 degrees would be challenging in itself; when this oil is also sour, the challenges are magnified many-fold, especially when considering the limited space on offshore drilling rigs.

Saudi Aramco has started a program aimed at exploration and evaluation of heavy oil reserves in the Arabian Gulf. The objective of testing this sour, heavy oil was to obtain reservoir fluid samples, get productivity data and characterize the reservoir. While attempting to dispose of the oil in an efficient manner, initial attempts to test this heavy oil were unsuccessful. Prematurely terminating these tests resulted in not obtaining all of the required test data.

A heavy oil team was formed in early 2008 to determine solutions to the inability to properly characterize the reservoir on heavy oil well tests. This multidisciplinary team of professionals held two workshops, where heavy oil experts from major service companies provided their global expertise. This information was then blended with local operational requirements to create a unique well testing design. This design has successfully been implemented in two wells (onshore and offshore).

The use of an Electric Submersible Pump (ESP) although common in production scenarios, was successfully implemented for the first time on a heavy oil drill stem test in Saudi Arabia.

This paper summarizes the problems associated with testing heavy oil, the options studied, the reasons for selection of the chosen test method, the downsides of the selected plan, the trial testing on land and the successful implementation of the final plan in an offshore environment. It is a summary of the planning process necessary to get a good heavy oil test in a sensitive offshore environment.
Predicting Lower Fars Heavy Oil Molar Compositions Using Artificial Neural Networks
Authors: Al-Sirri Dalal , Gharbi Ridha
Published: December 2011

Characterizing reservoir fluid composition is a crucial step in all phases of the exploration and development cycle of any oil field. The petroleum industry has dedicated much work to build up computational techniques to model phase behavior through two approaches using conventional regression methods and the Equation-of-State models. Recently, Artificial Neural Networks (ANN) have been successfully used to solve numerous problems in the petroleum industry. This interest is due to the fact that neural networks generally have large degrees of freedom, thus they can capture the nonlinearity of the process being studied better than regression techniques. In addition, neural networks have the ability to model systems with multiple inputs and outputs.

The objective of this study was to develop a neural network model to predict the molar compositions of heavy oil as functions of the well location, depth, bottomhole temperature, bottomhole pressure, API gravity, and gas gravity. Since composition may change vertically as well as laterally, well location and depth of the samples are included in the training of the neural network. A total of nine pseudocomponents are used as output variables.

The data, on which the network was trained, contained 82 data sets collected from Lower Fars heavy oil reservoir of north Kuwait. Several neural network architectures were investigated to obtain the most accurate model. Results indicate that general regression neural network shows optimum prediction capability for molar compositions as functions of the input variables. In addition, the model was able to successfully predict the molar compositions from inputs that were not seen during the training process. The output of this study is in accordance with the new vision and strategy that Kuwait Oil Company has set toward the exploitation of the unconventional heavy oil resources of Lower Fars reservoir of North Kuwait in which a lot of new wells will be drilled in this area. A development of such a new and innovative prediction model using ANN approach is of great importance in providing the molar composition of Lower Fars heavy oil reservoir, starting only from basic available data, with a limitation of a reliable PVT data base.
Importance of Thermal Consolidation of Shale During SAGD Process
Authors: Bois Axel-Pierre , Mainguy Marc
Published: December 2011

Most of the oil sand deposits contain shale barriers of various sizes and with a space distribution difficult to appraise. These shale barriers can lower the reserves and reduce the efficiency of the SAGD process by slowing down steam chamber propagation. The detrimental effect of shale barriers on the SAGD process has been demonstrated by many simulation works and research projects have been launched to develop new technologies favoring breakdown of shale barriers.

The effects of high temperatures on shale are difficult to assess. Field data from SAGD projects show that steam might either bypass shale barriers or breakthrough them, but the conditions favoring these mechanisms are unclear. Lab data show that the constitutive mechanical behavior of clayey materials is strongly sensitive to high temperatures. Of particular importance is the phenomenon of thermal consolidation of clay which was never pointed out to explain the conditions of failure of shale barriers during SAGD. Thermal consolidation denotes an irreversible contraction of clayey materials when heated under drained condition.

This paper presents the results of a project that aimed at evaluating if thermal consolidation could help increase permeability of shale barriers. A comprehensive review of published data shows that the origin of this phenomenon is still poorly understood despite some important factors can be highlighted. It also shows that stress path applied during thermal expansion tests on shale specimens strongly control the thermal consolidation phenomenon, which can lead to erroneous interpretations of these tests. It proposes a very simple model that is used to show 1) under which conditions thermal consolidation of shale barriers might happen; and 2) the consequences of thermal consolidation in terms of permeability changes of shale.
Downhole Fluid Sampling in Shallow Viscous Reservoir - Innovative Techniques Helped in Overcoming the Challenge
Authors: Ahmed Khalid , Al-Sammak Ibrahim , Ahmad Fatma , Abbas Faisal , Vasquez Rafael , Al-Jabari Naim , Cook Reg
Published: December 2011

Downhole fluid sampling in shallow unconsolidated reservoir having high inter-granular porosity and filled with viscous oil is quite challenging. The dominant formation properties, relevant to fluid flow, like low pressure, rock’s mechanical weakness, drilling damage and fluids mobility ratios, despite very high permeabilities, have resulted in the failure or impracticality of the conventional and most obvious methods- for example the sampling with Dual/Straddle Packers.

The problems faced during sampling are: i) plugging of flowline, ii) emulsion generation iii) sand production- leading to caving around sampling tool and iv) marginal operating limit of pressure drawdown-dictated by extremely low formation pressure and little difference between hydrostatic and formation pressures. Mostly, the flow happens in surges and any increase in flow rate causes large drag on sand grains and excess pressure drawdown.

A thoughtful mix-up of technology, understanding of rock mechanics, innovative operating techniques and proper coordination by aligning all concerned has helped in meeting the challenge of sampling viscous oils in the unconsolidated sand.

A log-based Geo-Mechanical study suggested very low unconfined compressive strength for the sand, restricting the flow rate to as low as 2 cc/s. Dual/Straddle Packers, with its large volume at this low flow rate, would require very long hours of pumping. Typically, the volume between packers would take 5 to 6 hours of continuous pumping at the suggested maximum rate of 2cc/s; just sufficient to start pumping out from the formation. A normal probe would cause sanding at probe head due to the reduced cross section to flow. The most successful approach was the selection of: a) probes with enlarged cross section to flow, which reduce the drawdown by decreasing the flow velocity at the sand face, b) ultra slow pump out rates to negotiate drawdown, formation weakness and mobility ratios of water/filtrate and viscous oil.

Multiple sand filters in the flow line, segregation of emulsified filtrate through innovative techniques and state-of-the art fluid analysis methods helped to determine exactly when the viscous oil started to flow. However, the surge nature of flow still resulted in 20 to 30% contamination in the sampled oil.

The obtained PVT-quality downhole sample helped in determining the in-situ fluid properties of the viscous oil.
Analysis and Prediction of Heavy Oil Two-Phase Slug Length in Horizontal Pipelines
Authors: Al-Safran E. M. , Gokcal B. , Sarica C.
Published: December 2011

The recent trends of increasing energy demand led the industry toward the development of heavy oil unconventional resources. However, the production and transportation of such heavy oil is a challenge due to the lack of understanding of the two-phase flow behavior under the condition of high viscosity liquid phase. The objective of this study is to physically understand and quantify the effect of liquid viscosity on slug length and develop two-phase slug length correlation for high oil viscosity. The developed slug length correlation can improve the existing mechnistics two-phase flow models in the development and maintenance of heavy oil fields.

Experimental high viscosity (0.181-0.589 Pa.s) two-phase air/mineral viscous oil slug length data is acquired in a horizontal 0.0508-m ID pipe. Data analysis showed a one third reduction in the average slug length compared to the average slug length under low viscosity condition. Furthermore, statistical analyses showed a significant effect of liquid phase viscosity on slug length distribution including maximum slug length and slug length variation. High speed recorded flow visualization revealed the effect of liquid phase viscosity on the scooping and shedding processes at the front and back of the slug, respectively; which is speculated to reduce the slug length. In addition, a proposed physical model suggests that the thick liquid film in the Taylor bubble zone and the short slug mixing zone result in a fully developed velocity profile at slug back stabilizing the slug at a shorter length. A new dimensional analysis based model is proposed to predict average slug length for high viscosity liquid slug flow. A validation and comparison study of the proposed correlation showed the best performance amongst the existing correlations.
Surveillance Improvements During the Implementation of a Large Scale Carbonate Steamflood Pilot, Wafra field, PZ
Authors: Hoadley Steven , Al-Yami Falah , Deemer Art , Brown Joel , Al-Mutairi Ghanim , Lekia Solomon , Al-Dhafeeri Fahad , Al-Odhailah Fares , Barge David
Published: December 2011

A large scale carbonate steamflood pilot is being conducted in the Wafra field in the Partitioned Zone between the Kingdom of Saudi Arabia and the State of Kuwait. The primary objectives of the pilot are to reduce the technical uncertainties and economic risks associated with carbonate steamflooding and to determine feasibility for full field steamflood development. To help in accomplishing this objective, a Surveillance Plan, linked to an uncertainty management plan, was developed and implemented to focus the data gathering and analysis necessary to meet the project objectives.

The uncertainty management plan identified key uncertainties that must be mitigated to reduce the risk for full field steamflood development in the Wafra field. To reduce these uncertainties, a thermal surveillance plan was created that represented the measurements required on reservoir and facilities performance to evaluate the pilot performance and provide the information needed for the design and operation of a full field development. Each data element identified in the surveillance plan required a process for collecting, quality control, and storage of the information. The surveillance plan is designed to be an evergreen document with the flexibility to add and define new data collection requirements as required by the project response.

Because there are few carbonate steamfloods in the world, the LSP project has unique challenges that have not been typically encountered in other better understood sandstone thermal projects. Some surveillance activities were expanded as a result of observations occurring in the field and were added to the surveillance plan to enhance the understanding of the steamflood response.
Heavy Oil Production With Steam Injection Using ESPs
Authors: Issa Mohammed , Fleming James , Wonitoy Kelvin
Published: December 2011

Heavy oil production using steam injection has become a common method of extracting oil. It is considered an enhanced oil recovery (EOR) method and is one of the extraction methods used in thermal stimulation of oil reservoirs. Steam injection is widely used in the San Joaquin Valley of California (USA), the oil sands of northern Alberta (Canada) and Venezuela. Steam assisted gravity drainage (SAGD) has become one of the more cost effective methods of producing fluid from oil sand reservoirs. This same technology is being applied to heavy oil reservoirs where viscosity is an issue.

Wells involving steam injection operate at bottom hole temperatures (BHT) of 180°C to 250°C This is true when electrical submersible pumping systems (ESPs) are used, however when gas lift or rod lift are employed the BHT can exceed 320°C. This market requirement pushed the vendors to develop ESPs capable of operating continuously at these temperatures for reasonably acceptable run times (2 yrs +). The equipment specifications for materials and designs for this type of application involve the use of many high tech metals and elastomers designed for extreme temperature operation and temperature cycling.

Steam assisted recovery projects challenge the ESPs with elevated temperatures, temperature cycling, H2S corrosion, abrasives, steam, and free gas.

Development of steam injection projects parallel the similar requirements for equipment development used to run in harsh environments (high H2S), H2S-resistant materials can be used in varying configurations depending on the H2S quantity and the BHT. High-strength shafting and corrosion-resistant couplings, fasteners, and housings offer the most protection from corrosive elements. Cable and motor lead extensions (MLE) benefit from the application of lead barrier protection. Major developments in the insulating materials required for the stator, cable and motor lead extension enabled operators to increase the reliability of the ESP even when exposed to high temperatures and corrosive environments.

The Centrilift CENtigrade™ elevated temperature production systems family is able to operate successfully in the harshest conditions. This product family consists of the Centrilift High Temperature™ ESP system, Centrilift Extreme Temperature™ ESP system, and Centrilift Ultra Temperature™ ESP system. Baker Hughes has a proven record of success with this equipment (Fort McMurray oil sands in Alberta, Canada), making it the first company to deploy ESPs capable of operating reliably at bottom hole temperatures as high as 250°C. The Baker Hughes Centrilift™ artificial lift product line offers ESPs, progressing cavity pumping systems (PCPs), gas lift, and surface pumps.

This paper will focus on the development, capabilities and the successful implementation of the CENtigrade production systems.
A New Perspective on Tracking Energy Transfer in SAGD derived from Three-Dimensional Numerical Field Scale Simulations
Authors: Ezeuko C. C , Wang J. , Sen A. , Gates I. D.
Published: December 2011

Numerical reservoir simulations have successfully been used for performance analysis of several commercial steam assisted gravity drainage (SAGD) heavy oil recovery projects. The inherently complex calculations involving mass and energy balances, along with consideration for advanced geomechanics, culminate in a strong time limitation for field scale simulations of SAGD processes. As a result, significantly homogeneous gridding has traditionally been used for downwell directions, with grids sizes sometimes exceeding 100 m for three dimensional simulations of SAGD. This represents a compromise which requires further quantitative analysis to clearly understand the implications on uniform steam chamber development and the accuracy of performance predictions. At this point, most simulations are not capable of predicting realistic field performance, especially in the downwell direction, of a given reservoir since grid resolution is poor. In this study, a full field reservoir model representative of a McMurray reservoir is used to analyze the implications of longitudinal grid homogeneity on the propagation of a SAGD steam chamber. In addition, a novel use of flowing steam quality plots to visualize steam migrations and characterize heat transfer during SAGD is presented. The results illustrate the requirements on grid block dimensions necessary to resolve heterogeneities and accurately represent physical phenomena such as flow and heat transfer. The findings of this work provide useful guidelines and have implications for future design and performance analysis of SAGD projects using numerical reservoir simulations.
How Would the Mandatory Adoption of IFRS Affect the Earnings Quality of U.S. Firms? Evidence from Cross-Listed Firms in the U.S.
Authors: Sun Jerry , Cahan Steven F. , Emanuel David
Published: December 2011

SYNOPSIS

We examine the impact of IFRS adoption on the earnings quality of foreign firms cross-listed in the U.S. from countries that have already adopted IFRS on a mandatory basis. We use the cross-listed firms as surrogates for the U.S. firms so we can observe the effect of IFRS adoption in the U.S. We examine five measures of earnings quality related to discretionary accruals, target beating, earnings persistence, timely loss recognition, and the earnings response coefficient (ERC). To isolate the effect of IFRS adoption, we use a matched sample design where each cross-listed firm is matched to a U.S. firm. We find the difference in earnings quality from the pre- to post-IFRS period is not different for the cross-listed and matched firms when earnings quality is measured by absolute discretionary accruals, timely loss recognition, or a long-window ERC. However, for the incidence of small positive earnings and earnings persistence, we find significant difference-in-differences, indicating that IFRS adoption led to an improvement in earnings quality for cross-listed firms relative to the matched firms. Our results are slightly surprising since U.S. GAAP is generally viewed as high-quality standards with little room for improvement.
On Alternative Measures of Accruals
Authors: Shi Linna , Zhang Huai
Published: December 2011

SYNOPSIS

This paper investigates the difference between two widely used measures of accruals and their differential impact on accrual strategy returns. The two measures are accruals computed using consecutive changes in the balance sheet items and accruals computed as earnings minus cash flows from operating activities, both from the cash flow statement. Our investigations reveal that the difference between the two measures is caused by four items and non-articulations in changes in working capital accounts and depreciation expenses, in addition to non-articulation events as identified by Hribar and Collins (2002). We find that the non-articulation in working capital accounts and depreciation expenses between the cash flow statement and other financial statements is surprisingly prevalent and economically significant, and it can be attributed to special events, errors made by Compustat, firms' inconsistent definitions, and non-standard classifications of assets/liabilities. We show that, after excluding non-articulation events, the accrual strategy returns are higher for accruals computed using balance sheet items than accruals computed using cash flow statement items. Further investigations suggest that the return differentials are mainly due to other funds from operations and the non-articulation in changes in accounts receivable.

JEL Classifications: G12; G14; M41.

Data Availability: Data used are available from the sources identified in the study.
Auditor Resignation and Firm Ownership Structure
Authors: Khalil Samer K. , Cohen Jeffrey R. , Trompeter Gregory M.
Published: December 2011

SYNOPSIS

This paper investigates whether the likelihood of auditor resignations and the associated stock market reaction in family firms is significantly different from that in non-family firms. It also examines whether the aforementioned associations vary with the identity of the CEO managing family firms (founder, descendant, or non-family CEO). Relying on a sample of auditor resignations in the U.S. over five calendar years, 2004–2008, and using two control samples (matched and random) as benchmarks, we document the following. First, the likelihood of auditor resignations in family firms is significantly lower than that in non-family firms. Second, auditor resignations in family firms managed by a founder or non-family CEO (descendant) are also less (more) frequent compared to non-family firms. Finally, abnormal returns following auditor resignations in family firms and in family firms managed by a non-family CEO are higher (less negative) than those in non-family firms. These results are robust to the selection bias resulting from family ownership and contribute to the literature investigating auditor portfolio management decisions.

Data Availability: All data are from publicly available sources.
Client Engagement Risks and the Auditor Search Period
Authors: Khalil Samer K. , Cohen Jeffrey R. , Schwartz Kenneth B.
Published: December 2011

SYNOPSIS

This paper investigates whether client engagement risks lengthen the client acceptance phase for audit firms and result in a longer auditor search period for their clients. Using a sample of auditor resignations over the period 2003–2008, we document that the auditor search period is longer for firms associated with client business risk (financial distress) and audit risk (internal control weaknesses or management integrity issues), while it is shorter for firms representing reduced auditor business risk (auditor industry specialization). These findings highlight the importance of client risk assessment and explain audit firms' response to perceived client risks.
Mandatory IFRS Adoption and the U.S. Home Bias
Authors: Khurana Inder K. , Michas Paul N.
Published: December 2011

SYNOPSIS

This paper examines whether mandatory IFRS adoption at the country level lowers U.S. investors' propensity to overweight domestic stocks in their common stock portfolios (generally referred to as home bias). We find that, on average, U.S. home bias decreases for countries that mandate IFRS adoption, after controlling for country-fixed effects. We also find that the reduction in the U.S. home bias after the mandatory adoption of IFRS is greater for countries with larger differences between IFRS and their domestic accounting standards, for countries with a stricter rule of law and a common law legal origin, and in countries with greater incentives to report high-quality financial information. Overall, our results indicate that a common set of global accounting standards matters for portfolio holdings of U.S. investors and that U.S. investors regard the enforcement of standards to be a key factor in making investments outside the U.S.

Data Availability: Data are publicly available.
A new convenient synthesis of 5-aryl-2-(arylamino)-1,3,4-oxadiazole derivatives
Authors: Kumar Sanjeev
Published: December 2011

Electrical energy offers numerous benefits for conducting a synthesis, including increased reaction rates, yield enhancements and cleaner chemistries. 5-Aryl-2-(arylamino)-1,3,4-oxadiazoles were synthesised directly from acylthiosemicarbazide on the platinum electrode under controlled potential electrolysis in an undivided cell assembly in acetonitrile.
Monitoring Pheasants (Phasianidae) in the Western Himalayas to Measure the Impact of Hydro-Electric Projects
Authors: Jolli Virat , Pandit Maharaj K.
Published: December 2011

Jolli V., Pandit M.K. 2011. Monitoring pheasants (Phasianidae) in the Western Himalayas to
measure the impact of hydro-electric projects. Ring 33, 1-2: 37-46.

In this study, we monitored pheasants abundance to measure the impact of a hydroelectric development project. The pheasants abundance was monitored using “call count” and line transect methods during breeding seasons in 2009-2011. Three call count stations and 3 transects were laid with varying levels of anthropogenic disturbance. To understand how the hydro power project could effect the pheasant population in the Jiwa Valley, we monitored it under two conditions; in the presence of hydro-electric project (HEP) construction and when human activity significantly declined. The Koklass Pheasant (Pucrasia
macrolopha), Cheer Pheasant (Catreus wallichi) and Western Tragopan (Tragopan melanocephalus) were not recorded in Manjhan Adit in 2009. During 2010 and 2011 springs, the construction activity was temporarily discontinued in Manjhan Adit. The pheasants responded positively to this and their abundance increased near disturbed sites (Manjhan Adit). The strong response of pheasants to anthropogenic disturbance has ecological application and thus can be used by wildlife management in the habitat quality monitoring in the Himalayan Mountains.
Biometrics of Non-Breeding Immature Mallards (Anas Platyrhynchos) in North-Eastern Poland
Authors: Jankowiak Łukasz , Polakowski Michał
Published: December 2011

Jankowiak Ł., Polakowski M. 2011. Biometrics of non-breeding immature Mallards (Anas
platyrhynchos) in north-eastern Poland. Ring 33, 1-2: 47-53. Non-breeding immature Mallards from north-eastern Poland (Północnopodlaska Lowland) were captured and measured (altogether 182 individuals in their 1st year of life). Immature males were significantly larger than females according to all analysed parameters. The length of bill and wing were the most sexually dimorphic traits and the least dimorphic were the total length of bill with head and tarsus length. The results of the present analysis and other studies in different regions of Europe suggest that wing size of Mallards follows Bergmann’s rule, while a bill size - Allen’s rule. Mallards from north-eastern Poland are larger than those from western Europe. We hypothesize that the reason for this is the fact that main population of non-breeding Mallards originates from the larger eastern European population, which is confirmed by some ringing data.
A Qualitative Investigation of Physical Therapists' Experiences and Feelings of Managing Patients With Nonspecific Low Back Pain
Authors: Jeffrey Janet E. , Foster Nadine E.
Published: December 2011

Background

Physical therapists' management of patients with nonspecific low back pain (NSLBP) has been found to be associated with their beliefs and attitudes toward NSLBP, as well as with guideline recommendations. Greater knowledge of physical therapists' experiences and feelings of treating patients with NSLBP may help to explain these associations and increase our understanding of some of the challenges physical therapists face when treating patients with NSLBP in clinical practice.

Objectives

The objective of this study was to understand more about how the personal experiences and feelings of physical therapists might influence their decision making when treating patients with NSLBP.

Design

This was a qualitative study using a phenomenological hermeneutical approach and practitioner-as-researcher model.

Methods

Eleven semistructured interviews with physical therapists were conducted and analyzed using the hermeneutical circle to identify key themes relating to their experiences and feelings in treating patients with NSLBP.

Results

Three linked themes emerged: (1) physical therapists believe that NSLBP has an underlying mechanical and recurring nature, (2) physical therapists' attitude toward managing NSLBP is to empower patients to exercise and self-manage their pain and functional problems, and (3) physical therapists experience feelings of tension between the advice and treatment they feel is best for their patient and the patient's own beliefs and attitudes.

Conclusions

The experiences and feelings of physical therapists treating patients with NSLBP include conflict among their pain beliefs, attitudes, and working partnerships with patients. Treatment decisions may be influenced when physical therapists modify their beliefs and attitudes to reduce this sense of conflict. Improving physical therapist communication skills may help decrease feelings of conflict, enhance working relationships, and encourage a more consistent approach toward patients with NSLBP.
Determination of an infectious dose of Leptospira for the performance of challenge test in assessing the efficacy of Leptospira vaccines
Authors: Nepeřený Jiří , Chumela Josef , Vrzal Vladimír
Published: December 2011

The efficacy of vaccines against leptospiral disease can be determined objectively by challenge test in experimental animals. Selection of suitable leptospiral challenge strains and determination of an optimal challenge dose to prove exactly that the given vaccine Leptospira serotype induces protective immunity in vaccinated dogs is a critical point in performing challenge experiments. The aim of our study was to verify and determine an appropriate challenge dose for efficacy tests in dogs for the following Leptospira serovars: L. grippotyphosa, L. icterohaemorrhagiae and L. canicola. The appropriate challenge dose was determined on the basis of pathognomonic symptoms of infection, Leptospira capture at cultivation and pathological changes in dogs infected experimentally with various doses (5 × 104 - 5 × 108) of Leptospira serovars. A dose of 5 × 106 of each respective serovar administered intraperitoneally was determined to be a suitable challenge dose. The dogs infected with the selected dose showed the typical symptoms of the disease and met the requirements of an objective and standard evaluation of the vaccine efficacy according to the pharmacopoeial monograph. A study of such extent was done for the first time in the Czech Republic.
Application of near infrared spectroscopy to estimate selected free amino acids and soluble nitrogen during cheese ripening
Authors: Mlček Jiří , Rop Otakar , Dohnal Vlastimil , Šustová Květoslava
Published: December 2011

This paper deals with the estimation of tyrosine, tryptophan and soluble nitrogen in 288 samples of the Edam cheese using the Near Infrared Spectroscopy. For analyses, the apparatus NIR Nicolet Antaris was used working in the regime of reflectance (i.e. using an integrating sphere) in combination with fibre optics (i.e. using a probe). For calibration, reference data from the UV spectrophotometer was used. Calibration models were developed using a PLS algorithm (least square method) and tested by means of cross-validation. Correlation coefficients: R = 0.911, R = 0.929 and R = 0.959 for soluble nitrogen, tryptophan and tyrosine, respectively, were achieved during measuring in the integrating sphere; R = 0.807, R = 0.945, R = 0.928 were achieved for soluble nitrogen, tryptophan and tyrosine, respectively, during measuring by probe. The results of the study show that NIR technology is suitable for fast and approximate determination of the level of cheese ripening. This can be used for the evaluation of the material for the processed cheese production, or cheese sale in optimal level of ripening.
The effect of glaze on the quality of frozen stored Alaska pollack (Theragra chalcogramma) fillets under stable and unstable conditions
Authors: Žoldoš Peter , Popelka Peter , Marcinčák Slavomír , Nagy Jozef , Mesarčová Lýdia , Pipová Monika , Jevinová Pavlína , Nagyová Alena , Maľa Pavel
Published: December 2011

Frozen fillets (n = 288) of Alaska pollack (Theragra chalcogramma) were used to evaluate the effect of glaze on lipid oxidation and microbiological indicators during 6 months of freezing storage under stable (−18 °C) and unstable temperature (varying from −5 to −18 °C) conditions. The amount of glaze, moisture, fat and protein content were measured. Despite the low fat content in Alaska pollack, a positive effect of glazing and stable freezing conditions of storage on the range of oxidative changes of lipids expressed as thiobarbituric acid reactive substances was found. Total counts of viable cells slightly rose before the end of the storage period in both groups with commercially glazed fish. The average counts of psychrotrophs in each group () were at the same level, ranging from 9.1 ×103CFU·g-1to 1.1 × 104CFU·g-1. According to the microbiological results fillets stored under unstable conditions were considered to be acceptable, but sensory evaluation showed that at the end of frozen storage they could not be consumed because of rancidity. Based on our results, glaze application ranged from 10 to 15% guarantee of final quality, however, prevention of temperature fluctuation during storage is important to keep the quality of the frozen fillets. This is the first similar study in Alaska pollack.
Nitrite toxicity assessment in Danio rerio and Poecilia reticulata
Authors: Doleželová Petra , Mácová Stanislava , Pištěková Vladimíra , Svobodová Zdeňka , Bedáňová Iveta , Voslářová Eva
Published: December 2011

Nitrite is a natural component of the nitrogen cycle in the environment. Although it usually occurs in low concentrations, elevated concentrations caused by effluents or affected nitrification process can lead to serious health deterioration of fish. Two aquarium fish zebrafish (Danio rerio) and guppy (Poecilia reticulata) are recommended to use as model organisms in toxicity tests. However, their sensitivity to nitrite can differ. The aim of this study was to define acute toxicity of nitrite by the semistatic method according to OECD No. 203 (Fish, Acute toxicity test). The series of 4 acute toxicity tests was performed, with 10 fish of both species used for each concentration and for the control. The 96hLC50 NO2- value for D. rerio and P. reticulata was 242.55 ± 15.79 mg·l-1 and 30.2 ± 8.74 mg·l-1, respectively. We have proved significant difference (p < 0.05) in sensitivity between D. rerio and P. reticulata. The results showed different sensitivities to nitrites in tested fish species, which could be related to species-specific branchial chloride uptake mechanism. This is the first study on this fish species.
Lead, mercury and cadmium content in bottom sediments, reed (Phragmites australis) beds and great pond snails (Lymnaea stagnalis) in fishponds and the role of littoral zones in their accumulation
Authors: Sychra Jan , Čelechovská Olga , Svobodová Zdeňka , Sychra Oldřich
Published: December 2011

We studied the contents of cadmium (Cd), lead (Pb) and mercury (Hg) in common reed (Phragmites australis), great pond snails (Lymnaea stagnalis), and in littoral bottom sediments in 18 fishponds in two regions of the Czech Republic. We also assessed the impact of environmental factors on heavy metal accumulation in these three components of littoral ecosystem. Cadmium and lead values were significantly higher in bottom sediments (median values 0.70 and 13.4 mg·kg-1) than in reed (0.014 and 0.51 mg·kg-1) and snails (0.074 and 0.81 mg·kg-1). Cadmium values in reed stems positively correlated with Cd values in great pond snails (Spearman’s rank correlation, rS = 0.62; p < 0.05). Cadmium and lead contents in reed stems positively correlated with each other (rS = 0.56; p < 0.05). The mercury values in snails (0.043 mg·kg-1) were higher than in sediments (0.040 mg·kg-1) and these were higher than in reed stems (0.010 mg·kg-1). We also found higher mercury contents in reed stems and higher cadmium contents in great pond snails in eastern compared to western parts of investigated ponds. Based on the principal component analysis (PCA) performed on heavy metal values, relative reed beds rate in the pond perimeter was negatively correlated with the sample scores on the first PCA axis and the orientation of sampling site and fish stock density negatively correlated with the second PCA axis. Our results proved the important role of littoral sediments in Cd, Pb and Hg accumulation, and the suitability of great pond snails for mercury stress biomonitoring in fishponds. In conclusion, littoral reed beds play a very important role in toxic element uptake in fishponds. The results contribute to the understanding of heavy metal cycles and their accumulation in fishponds under semi-natural conditions and in less affected landscape, and can be used as reference values for comparison with more damaged sites.
Cost-Effective Approaches to Reduce Greenhouse Gas Emissions through Public Transportation in Los Angeles, California
Authors: Gallivan Frank , Ang-Olson Jeff , Liban Cris B. , Kusumoto Alvin
Published: December 2011

The Los Angeles County, California, Metropolitan Transportation Authority (Metro) commissioned a study of strategic options for the agency to reduce greenhouse gas (GHG) emissions. This study compared a comprehensive range of strategies on potential GHG reductions and cost-effectiveness, in dollars per ton of GHG emissions reduced. Sixteen strategies were analyzed in four categories: promotion of alternative travel modes, transit service, vehicle technology, and facility energy use. Strategies with the greatest potential for GHG emission reductions (regardless of cost) included transit-oriented development, vanpool subsidy, onboard railcar energy storage, and ridesharing and transit programs for employers. The first three would save or generate money for Metro. Ridesharing and transit programs have the potential for net revenue generation, but the results were uncertain. Four more strategies would reduce smaller amounts of emissions while also saving money for the agency: recycled water for bus washing, low-water sanitary fixtures, Red Line tunnel lighting retrofits, and facility lighting efficiency. Understanding opportunities for GHG reductions requires expertise in transit operations, vehicles, facilities, and planning. Cost-effectiveness and total reduction potential can be supporting criteria in making funding decisions. The largest GHG reduction opportunities for Metro are typically those that reduce vehicle miles traveled, whereas many of the most cost-effective strategies address GHG emissions from facility energy use. Cost-effectiveness of a strategy to Metro can depend greatly on receipt of external funding, including federal funds or utility rebates. In some cases, the range of cost-effectiveness for a strategy is so great that it is not useful to inform decision making without some further definition.
Analysis of Cost-Effectiveness of Employment Transportation Services
Authors: Thakuriah Piyushimita (Vonu)
Published: December 2011

The author examined cost-effectiveness of employment transportation (ET) services funded by the Job Access and Reverse Commute program of FTA in 2002. These services transport low-wage workers to jobs. The author presented multiple sources of primary and administrative data on users and programs in 23 ET sites. ET cost per ride measures were compared with cost per ride measures of transit services that were operating in the same area (called peer transit services). A cost per user per year was estimated to determine the level of transportation investments on the mobility of low-wage workers. On a per ride basis, ET services cost more to deliver than did peer transit services, but a wide variation existed in the level of investments and subsidies among different types of users, areas, and types of service. The median estimated cost per ET service user per year was similar to the annual investment per recipient by several social and human services and workforce development programs that supported low-income individuals to achieve improved economic outcomes. ET annual expenditures were the greatest for low-wage individuals who were traveling to work and less so for low-income individuals who were traveling to job training, to look for jobs, or to shop and make other discretionary trips. Implications are drawn for human services transportation coordination and for data and reporting requirements.
Comparative Study of Pedestrian Accessibility to Transit Stations Using Free and Proprietary Network Data
Authors: Zielstra Dennis , Hochmair Hartwig H.
Published: December 2011

Availability of a transit service is a key factor in a traveler's choice of transportation mode. Transit service is a realistic option only if the service is available at or near locations when a person plans to travel. Whereas various measures exist for transit availability such as service frequency, the focus of this study was on the spatial aspect of pedestrian accessibility to transit stations, that is, on service coverage. Service areas are commonly used to visualize accessibility for pedestrians to transit systems and to analyze the potential ridership. Because the service area for a station is defined over the maximum network walking distance from a transit station, a complete street network that includes pedestrian segments, that is, shortcuts, is highly important for a realistic assessment of service areas. Whereas most proprietary geodata providers concentrate solely on car-related geodata, public domain street data and volunteered geographic information, such as OpenStreetMap, provide a potential valuable source for pedestrian data. The authors compared the amount of pedestrian-related data between freely available sources (OpenStreetMap or TIGER or both) and proprietary providers (Tele Atlas or NAVTEQ or both). The effect on modeling transit accessibility for pedestrians was analyzed for five U.S. and four German cities, and differences between these two countries were identified.
Generalized Framework for Developing a Corridor-Level Infrastructure Health Index
Authors: Verhoeven Jack , Flintsch Gerardo W.
Published: December 2011

Current practice in condition rating varies between states. Agencies use methods customized to meet the needs of the individual state. A lack of consistency in the methodology, data collection, and rating calculation techniques makes it difficult to compare assets across state borders and across asset types. To improve the overall condition of National Highway System (NHS) routes, a unified method of condition rating is needed. This paper presents a generalized framework for the rating of infrastructure assets at the corridor level. The paper provides steps that can be used for any asset type to calculate the health rating of the asset and the overall health of a corridor by combining the health ratings of all individual assets and asset types. The paper also presents results of a pilot demonstration of the proposed framework with data for Interstate 81, which were provided by the Virginia Department of Transportation. The health ratings can help engineers, planners, and policy makers to see the current condition of NHS routes and to monitor the results of using different maintenance, repair, and rehabilitation techniques at the state, regional, and national levels. The ratings can help to ensure that the condition of the nation's highway system is consistently at an acceptable level to the governing agency and users alike.
Alleviating Schedule Disruptions at Intermodal Freight Transfer Terminals
Authors: Chen Cheng-Chieh (Frank) , Schonfeld Paul
Published: December 2011

This study develops methods for countering schedule disruptions in intermodal or intramodal freight transportation systems operating in time-dependent, stochastic, and dynamic environments. When routine disruptions occur (e.g., traffic congestion, vehicle failures, or demand fluctuations) in preplanned intermodal timed-transfer systems, this dispatching control model determines through an optimization process whether each ready outbound vehicle should be dispatched immediately or held waiting for some late-incoming vehicles with connecting freight. Another submodel is developed to deal with the freight left over because of missed connections. Through a series of cases solved with a hybrid genetic algorithm–sequential quadratic programming algorithm, the model demonstrates its ability to minimize net costs through its dispatching decisions.
On the History of the Pony Express and Extending Its Operation into the Telegraph Era
Authors: Cottrell Wayne D.
Published: December 2011

The Pony Express was a horseback mail delivery endeavor that lasted from April 1860 until October 1861. The route extended from Saint Joseph, Missouri, to Sacramento, California, and then on to San Francisco, California, by boat. With letters sealed in a mail pouch, riders covered the 1,966-mi route in no more than 10 days. The fast pace was sustained by exchanging horses every 10 mi and riders every 75 to 100 mi. The Pony Express ceased operations amid huge financial losses and the completion of the transcontinental telegraph. This study reviews its history and asks whether a healthy, solvent Pony Express could have survived competition from the telegraph until completion of the transcontinental railroad in 1869. A trinomial logit model compares the probabilities of choosing between standard mail, Pony Express, and telegraph. Market shares of 96.5% for standard mail, 2% for telegraph, and 1.4% for Pony Express are estimated on the basis of their 1861 prices and other historical information. Lowering the Pony Express rate from $1 to $0.30 per ½ oz would have doubled the market share, and increased the annual number of letters from 104,000 to 208,000. But the $62,400 earnings would have failed to meet the operating costs, and raising the rate would have meant a loss of customers. The Pony Express, therefore, would not have withstood competition from the telegraph. It would have had to shift its service market to package delivery, probably early on, to have sustained the operation. The Pony Express is nonetheless considered responsible for advancing transportation and communication in the United States.