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Chemical Characterization of Slags from an Old Smelter in Chihuahua, Mexico

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Journal of Minerals and Materials Characterization and Engineering 2022年第6期10卷 461-476页

作者： daphne espejel-garcía Vanessa Verónica espejel-garcía Alejandro Villalobos-Aragón Facultad de Ingeniería Universidad Autónoma de Chihuahua Chihuahua México

Slag is waste from pyrometallurgical processing, usually stored in stacks or warehouses around or near smelters. Slag research has focused on potential environmental problems associated with slag weathering or processing for secondary metal recovery and/or other uses (construction, landscaping, etc.). Located in northern Mexico, the city of Chihuahua has a mining history that dates back to the eighteenth century. A lead smelter located southeast of Chihuahua City;closed in 1997, leaving behind a large pile of slag. In this study, a chemical analysis of smelter slag was carried out. The tailings contain Zn (15 - 35 wt%), Pb (0.5 - 4 wt%), As (0.6 wt%), Sn (888 ppb) and Hg (170 ppb). XRD identified several minerals such as hardystonite (Ca2ZnSi2O7), melanotekite (), kentrolite () and sphalerite (ZnS) in the glass. Major elements are present in phases such as monticellite (CaMgSiO4), kirschsteinite (CaFe2+SiO4), hedenbergite (CaFe2+Si2O6), babingtonite (Fe2Si3O9), magnetite (Fe3O4), and calcite (CaCO3). Whether the goal is reuse, recycling or remediation, research into the properties of slag and its environmental and health impacts (on vulnerable exposed populations) should continue to be relevant.

关键词： Slag Smelter Contamination Pyrometallurgical Processing

Shallow Subsurface Stratigraphy Inferred from the Use of Vertical Electrical Soundings (VES) Survey in Central Chihuahua, Mexico

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Open Journal of Geology 2019年第1期9卷 15-28页

作者： Alejandro Villalobos-Aragón Vanessa V. espejel-garcía daphne espejel-garcía Lucio Rivas-Lobera Facultad de Ingeniería Universidad Autónoma de Chihuahua Chihuahua México

Vertical Electrical Soundings (VES) provide fast and economical measurements used in geophysical exploration. VES were carried out in El Sauz-Encinillas (ESE) aquifer, in northern Mexico, to determine apparent resistivity and geoelectrical units’ thickness. Despite it being one of the three main aquifers feeding Chihuahua city, a lack of available geophysical data prevails in its northern portion. The main goal of this study was the determination of the geoelectrical units in the subsurface stratigraphy via electrical-resistivity soundings. The ESE’ aquifer is located within alluvial Quaternary sediments, with varying granulometry and reaching from a few meters to more than 600 meters of thickness at the center of the valley. Forty-five vertical electrical resistivity soundings (Schlumberger array, maximum AB/2 distance of 500 m) were performed throughout ESE aquifer’s northern portion. Field data were analyzed using software. Results illustrate a wide variability in resistivity values throughout the study area. Five geoelectrical units were identified: 1) a hardpan topsoil, with resistivity values ranging from 200 - 800 Ω-m;2) an alluvial material mixture (sand/silt) with resistivity values ranging from 25 to 100 Ω-m;3) playa lake-type material (clay/evaporites mixture) with resistivity values ranging from 0.2 to 15 Ω-m;4) a gravel/sand mixture with resistivity values from 100 to 300 Ω-m;and 5) a partly fractured rock or conglomeratic material with resistivity values ranging from 400 to 3500 Ω-m. The electrical resistivity data, therefore gives reasonably accurate results that can be used to understand the subsurface stratigraphy and basement configuration in groundwater exploration.

关键词： Geophysics Vertical Electric Soundings Geoelectrical Sections

Groundwater Quality and Its Impact on Health: A Preliminary Evaluation of Dental Fluorosis in Julimes, Chihuahua, Mexico

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Journal of Water Resource and Protection 2020年第7期12卷 545-557页

作者： Aida Verónica Ontiveros-Terrazas Alejandro Villalobos-Aragón Vanessa Verónica espejel-garcía daphne espejel-garcía Facultad de Ingeniería Universidad Autónoma de Chihuahua Chihuahua México

Medical Geology can be defined as the branch of geology dealing with the relationship between natural geological aspects and health in organisms (humans and animals), trying to determine the influence of ordinary environmental factors on the geographical distribution of health issues. The main goals of this research were: 1) to evaluate the severity of dental fluorosis (DF) and fluoride concentration in groundwater, used for human consumption, as an indicator of overexposure to fluorides, 2) to estimate the Community Fluorosis Index (CFI) in the Julimes municipality in Chihuahua, Mexico. Nine water samples were collected in four locations in the Julimes area: Hacienda Humboldt, La Regina, Colonia San Jose, and Julimes. Samples were collected and stored in accordance with the Mexican standard (NOM-014-SSA1-1993). All the samples exceeded the maximum permissible limit established in the modified Mexican standard (NOM-127-SSA1-1994) of 1.5 mgL-1 for fluoride in water for human consumption. Average concentrations of 2.74 mgL-1 were found in Colonia San Jose, 2.19 mgL-1 in La Regina, 2.17 mgL-1 in Julimes and 2.06 mgL-1 in Hacienda Humboldt. Dental Fluorosis diagnosis was evaluated using the Dean Index and the CFI applied to residents. A total of 100 inhabitants were examined, with interviews and oral examinations also carried out. Dental Fluorosis prevalence was 92% overall for the municipality, while for Colonia San Jose was of 100%, of 88.89% for Hacienda Humboldt, 88.24% for Julimes and 96% for La Regina. Dental Fluorosis’ severity for the Julimes municipality was distributed as follows: 2% normal, 6% questionable, 8% very mild, 13% mild, 19% moderate, and 52% severe. An average CFI was found for the four localities of 3.02 points, with a very notable impact on public health.

关键词： Dental Fluorosis Dean Index Community Fluorosis Index Chihuahua

Volcaniclastic Deposit Analysis Using Grain Size, Digital and Stereological Techniques

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Open Journal of Civil Engineering 2023年第4期13卷 723-741页

作者： Alberto Rangel-Durán Vanessa Verónica espejel-garcía Alejandro Villalobos-Aragón daphne espejel-garcía Jorge Lucero-Álvarez Abraham Gilberto Mendez-Salas Facultad de Ingeniería Universidad Autónoma de Chihuahua Chihuahua México Facultad de Zootecnia y Ecología Universidad Autónoma de Chihuahua Chihuahua México

This study undertook a comprehensive sedimentological and grain-size analysis of two previously uncharacterized volcanoclastic deposits exposed in the northwestern sector of Chihuahua City, Mexico. The primary objective was to propose a systematic genetic classification for these deposits, employing traditional sedimentological techniques and an advanced computerized granulometric analysis technique based on orthogonal images to discern their grain size distribution. Through these studies, evidence was sought to classify them genetically, presenting arguments to define them either as a lahar or a volcanic debris avalanche. Results were critically compared against existing literature data pertaining to lahars and debris avalanches, yielding moderate success. The analysis identified one of the deposits as a non-eruptive or post-eruptive lahar. This identification was substantiated by the delineation of distinct overbank and transition facies within the deposit, providing compelling evidence for its genetic classification.

关键词： Volcaniclastic Lahar Avalanche Statistics Chihuahua

Implementation of an Available Parking Space Detection System in Hectic Parking Lots

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Journal of Transportation Technologies 2021年第4期11卷 688-701页

作者： Diana Laura Gómez-Ruíz daphne espejel-garcía Graciela Ramírez-Alonso Vanessa Verónica espejel-garcía Alejandro Villalobos-Aragón Facultad de Ingeniería Universidad Autónoma de Chihuahua Chihuahua México

Parking automation has been developed for locating available parking spaces inside a parking lot with new technologies, such as automatic collection, capacity, or empty spaces’ detection;to both reduce search time and avoid crowds of vehicles waiting to park in it. A simple detection system of available spaces, within the Faculty and Staff parking lot of the Engineering and Chemistry Departments at the Autonomous University of Chihuahua, Mexico (UACH), was set up. First, an analysis of vehicle capacity was carried out to establish the peak hours of vehicles’ entrances and compare it to the parking lots’ capacity. For one working week (6 days), it was determined that Tuesdays have the highest vehicle occupancy, and Saturdays are the days with the least traffic. Second, the geometric design of the parking lot (divided into two areas because of the terrain topography: upper and bottom levels), its dimensions and location of parking spots and marks on the pavement for traffic directions, were obtained from its blueprint, to visualize how the surveillance cameras can be oriented to cover the area. A detection system prototype was created for a specific area of the parking lot, using an artificial vision technique to perform the video extraction, while the digital image processing was developed in MATLAB. To complement and achieve the objective, Object- Oriented Programming (OOP) was used to obtain the count analysis as well as the availability/occupancy of each of the parking areas. This information is shown on a web page, with a simple driver-friendly design, since

关键词： Geometric Design Machine Vision Digital Processing OOP Web Page

Using TiO2-Biocharcoal and TiO2-Diatomite for Photodisinfection in Washing Machine Wastewater

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Journal of Geoscience and Environment Protection 2024年第8期12卷 62-79页

作者： daphne Montesuma Ferro Paloma Otsuka Kotani Regina Affonso Nilce Ortiz Chemistry and Environment Center Nuclear and Energy Research Institute IPEN So Paulo Brazil Biotechnology Center Nuclear and Energy Research Institute IPEN So Paulo Brazil

The photodisinfection process using biomolded semiconductor photocatalysts can inactivate bacteria in wastewater washing machine samples. The comparative study evaluated the photocatalyst material titanium dioxide (TiO2) synthesized with diatomite and biocharcoal biotemplate (TiO2-Biocharcoal and TiO2-Diatomite) in photodisinfection processes using domestic washing machine wastewater samples, the results of bacterial inactivation were above 96%. The efficiency of the photodisinfection process was evaluated by counting the number of colonies of the bacteria. Experiments under LED solar lamps presented similar bacterial inactivation, and a correlation with kinetic models. The kinetic study demonstrated a curved regression, indicating a better fit with the Hom model. A tail at the end of the modeling curve indicates the presence of a high concentration of inactive bacteria in the medium, while a shoulder at the beginning of the curve suggests a heterogeneous sample with a high concentration of gram-positive bacteria. The toxicity tests performed with wastewater samples without light exposure indicated low toxicity for both materials. The study presented promising disinfection results for an accessible and efficient photo-sterilization process of water contaminated with bacteria using abundant solar and renewable energy throughout the national territory. .

关键词： Photodisinfection Diatomite Biocharcoal Wastewater Titanium Dioxide

A Comparison among Manual and Automatic Calibration Methods in VISSIM in an Expressway (Chihuahua, Mexico)

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Open Journal of Civil Engineering 2017年第4期7卷 539-552页

作者： daphne espejel-garcia Jose Alejandro Saniger-Alba Gilberto Wenglas-Lara Vanessa Veronica espejel-garcia Alejandro Villalobos-Aragon Facultad de Ingenieria Universidad Autonoma de Chihuahua Chihuahua Mexico PTV Group Mexico Ciudad de Mexico Mexico

Traffic microsimulation is an essential tool in urban transportation and road planning. Its calibration is essential to attain representative results validated with real-world conditions. VISSIM (Verkehr in Städten—SIMulationsmodell) operates with the Wiedemann’s psycho-physical car-following model for freeway travel that considers safety distances (standstill and movement) during simulation. Calibration in this paper was achieved by using two different approaches: a) manual and b) genetic algorithm (with the GEH statistic formula) calibration techniques. Calibration and validation of this model were performed at the Periferico de la Juventud expressway in Chihuahua City, in northern Mexico. The Periferico de la Juventud (PDJ) has a N-S orientation and a length of ca. 20 km, with its northern section being its most congested portion. Its highest vehicle volume occurs at noon, with 3700 vehicles per hour, with 95% being passenger cars and the other 5% heavy goods vehicles. PDJ’s speed limit is 70 km·h-1, but the driver’s behavior has a tendency towards the aggressive performance. A total of 82 standstill and 82 look-ahead distances were obtained from unmanned aerial vehicles (UAV) images, with values ranging from 0.8 to 4.7 m and from 0.2 to 28 m, respectively. VISSIM calibrated parameter values were calculated for this expressway, being slightly above than the VISSIM default ones;and was validated with travel times and look-ahead distances. Results contribute information for the city’s future installment of public transportation systems, and should help decision makers deal with future urban planning.

关键词： VISSIM Genetic Algorithm Calibration Expressway Chihuahua

Urinary biomarkers for prostate cancer： a review

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Asian Journal of Andrology 2013年第3期15卷 333-339页

作者： daphne Hessels Jack A Schalken NovioGendix BV Nijmegen 6525 GA The Netherlands Department of Urology Radboud University Nijmegen Medical Centre Nijmegen 6500 HB The Netherlands

Although the routine use of serum prostate-specific antigen （PSA） testing has undoubtedly increased prostate cancer （PCa） detection, one of its main drawbacks is its lack of specificity. As a consequence, many men undergo unnecessary biopsies or treatments for indolent tumours. PCa-specific markers are needed for the early detection of the disease and the prediction of aggressiveness of a prostate tumour. Since PCa is a heterogeneous disease, a panel of tumour markers is fundamental for a more precise diagnosis. Several biomarkers are promising due to their specificity for the disease in tissue. However, tissue is unsuitable as a possible screening tool. Since urine can be easily obtained in a non-invasive manner, it is a promising substrate for biomarker testing. This article reviews the biomarkers for the non-invasive testing of PCa in urine.

关键词： biomarkers diagnosis prostate cancer (PCa) urinary biomarkers urine

Higher radiation dose with a shorter treatment duration improves outcome for locally advanced carcinoma of anal canal

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World Journal of Gastroenterology 2007年第6期13卷 895-900页

作者： Kim Huang daphne Haas-Kogan Vivian Weinberg Richard Krieg Department of Radiation Oncology University of California San Francisco CA United States Comprehensive Cancer Center Biostatistics Core University of California San Francisco CA United States

AIM： To assess whether radiation dose and duration of treatment influence local control and survival of patients with locally advanced anal cancer treated with definitive chemoradiation. METHODS： Twenty-eight consecutive patients who were treated with definitive radiation therapy for bulky anal cancers （〉 5 cm in size） were reviewed. Nineteen patients had T3 lesions, 8 patients had T4 lesions, and 15 patients had lymph node involvement. The median tumor size was 7.5 cm. All but one patient received concurrent chemoradiation. The median radiation dose was 54 Gy. The median duration of treatment was 58 d. RESULTS： With a median follow-up of 2.5 years in all patients and 7.8 years in living patients, the 2-year local recurrence-free probability was 570 and overall survival rate was 67%. Neither radiation dose nor duration of treatment alone was predictive of either time to local failure or overall survival. However, longer treatment breaks can potentially mask an advantage over higher radiation doses. Therefore, we examined those patients who received ≥ 54 Gy within 60 d, comparing them to the rest of the patients. Of patients who received ≥54 Gy within 60 d, local progression-free probability was 890 versus 420 for the rest of the group （P = 0.01）. CONCLUSION： Local failure is a significant problem in locally advanced carcinomas of-the anal canal. Higher radiation doses with limited treatment breaks may offer an increase in local control and survival.

关键词： Anal carcinoma Locally advanced Chemoradiation