Nuevo registro de Govenia purpusii (Orchidaceae) en el Parque Nacional La Malinche, Tlaxcala

The formicofauna of temperate Mexican ecosystems have been studied poorly. The objective of this study was to document the number of ant species in the protected natural area of La Malinche National Park, which features a temperate ecosystem in central Mexico. Furthermore, this study serves to update the list of species for Tlaxcala State in this area of the country. During 2015 to 2016, samples were collected along six 400 m linear transects in oak forest and agricultural land (2,700, 2,800, and 2,900 masl), using pitfall traps, baits with either protein or sugar, and hand collection from plants (where ants were foraging for floral nectar, extrafloral nectar, or honeydew). Twenty-three ant species belonging to 14 genera, 11 tribes, and 4 subfamilies were collected in La Malinche National Park. One genus (Brachymyrmex Mayr [Hymenoptera: Formicidae]), 7 species in the park, and 5 species in Tlaxcala State were new collection records. In pitfall traps, 23 species were recorded, where Dorymyrmex insanus Buckley, Formica densiventris Viereck, Lasius mexicanus Wheeler, and Brachymyrmex musculus Forel (all Hymenoptera: Formicidae) were collected exclusively from agricultural land. Temnothorax brevispinosus MacKay and Stenamma huachucanum Smith (both Hymenoptera: Formicidae) were collected exclusively in the oak forest, whereas 17 species were recovered from both habitats. Nine species were recorded from either protein or sugar baits; Formica propatula Francoeur and Temnothorax texanus Wheeler (both Hymenoptera: Formicidae) were recorded only in tuna baits, and with the remainder of the species collected with tuna and honey. Seven ant species were recorded from hand collections on plants. We have increased the number of ant species in Tlaxcala State from 53 to 58 (28 of which are present in La Malinche National Park). This faunal survey demonstrated that there is a great diversity of ant species in this temperate ecosystem. It is urgent to document the diversity of formicofauna in these types of ecosystems because they may possibly be the first to be negatively affected by climate change. Resumen La formicofauna de los ecosistemas templados ha sido pobremente estudiada. El objetivo de este estudio fue documentar el numero de especies de hormigas en el area natural protegida del Parque Nacional La Malinche, que cuenta con un ecosistema templado en el centro de Mexico. Ademas, este estudio actualiza la lista de especies de hormigas para el Estado de Tlaxcala en esta area del pais. Durante 2015 y 2016, las muestras fueron colectadas a lo largo de seis transectos lineales de 400 m en bosque de encino y campo de cultivo (2.700, 2.800, y 2.900 m sobre el nivel del mar), usando trampas pitfall, cebos con proteina o azucar, y colecta manual sobre plantas (donde las hormigas estaban forrajeando nectar floral, nectar extrafloral, o honeydew). Veintitres especies de hormigas pertenecientes a 14 generos, 11 tribus, y 4 subfamilias fueron colectadas en el Parque Nacional La Malinche. Un genero (Brachymyrmex Mayr [Hymenoptera: Formicidae]), 7 especies en el Parque Nacional La Malinche, y 5 especies en el estado de Tlaxcala fueron nuevos registros. En trampas pitfall, 23 especies fueron colectadas, de estas, Dorymyrmex insanus Buckley, Formica densiventris Viereck, Lasius mexicanus Wheeler, y B. musculus Forel (todas Hymenoptera: Formicidae) fueron exclusivamente colectadas del campo de cultivo. Temnothorax brevispinosus MacKay y Stenamma huachucanum Smith (ambas Hymenoptera: Formicidae) fueron exclusivamente colectadas en el bosque de encino, mientras que 17 especies se registraron en ambos habitats. Nueve especies fueron colectadas con cebos de proteina o azucar; Formica propatula Francoeur y Temnothorax texanus Wheeler (ambas Hymenoptera: Formicidae) fueron registradas solo en cebos de atun, y el resto de las especies fueron registradas en cebos de atun y miel. Siete especies fueron registradas a partir de la colecta manual sobre las plantas. Hemos incrementado el numero de especies de hormigas conocidas en el estado de Tlaxcala de 53 a 58 (28 de las cuales estan presentes en el Parque Nacional La Malinche). Este estudio de fauna demostro que hay una gran diversidad de especies de hormigas en este ecosistema templado. Es urgente documentar la diversidad de formicofauna en estos tipos de ecosistemas porque esta puede ser posiblemente la primera en ser afectada negativamente por el cambio climatico. Key Words: Tlaxcala State; Formicinae; Myrmicinae; oak forest; agricultural land; protected natural area View this article in BioOne

Reactivity Monitoring of Accelerator-Driven Nuclear Reactor Systems

Spatial interpolation is commonly used to generate water quality surfaces, but different spatial interpolation methods yield different surfaces from the same data. The water quality map produced using one model of spatial interpolation method may be significantly different from the map produced using another model of the same spatial interpolation method. The purpose of this study was to evaluate the performance of different spatial interpolation methods to depict the water quality of Lahore correctly. The water samples (n = 73) were collected from tube wells and tested for physicochemical parameters (pH, turbidity, hardness, total dissolved solids, alkalinity, calcium, and chlorides). The data exploration was performed using SPSS software. The inter-comparison of different powers of inverse distance weighting (IDW) and different functions of radial basis functions (RBF) was completed using geostatistical analyst extension in ArcGIS 10.3. Moreover, these deterministic interpolation methods (IDW and RBF) were compared with geostatistical interpolation methods (ordinary kriging and ordinary co-kriging) based on cross-validation statistics; root means square error (RMSE). The analysis showed that ordinary co-kriging performed much better than ordinary kriging, RBF, and IDW, for water quality assessment of Lahore. Hence, ordinary co-kriging with appropriate auxiliary variable and the best-fitted semi-variogram model was used to generate the spatial distribution map for each water quality parameter. The water quality index (WQI) was computed using the tested physicochemical parameters, and the results showed that 98% of the tube wells were providing ‘excellent’ to ‘good’ water quality in Lahore city. However, there were few areas of City and Anarkali subdivisions where it indicated poor to very poor water quality. The procedure used in this study is valuable for the water management authorities to better understand and monitor the groundwater quality.

Monitoring emotions and cooperative behavior

Soil and groundwater remediation Act was enacted in year 2000. More than ten years has already passed, Monitoring project has been completed,pollution status has been defined,contaminated sites depollution have been launched,a great progress has been made. This paper majorly to depict the extensive farmland soil qauality monittoring which is unpredent in Taiwan and believe has never been done worldwide. This project was initiated from February 8 th , 2002 to August 8 th , 2002. The project tasks including digitalization of cadastre, farmland listing, basic information collecting, field investigation, sampling & analysis planning, field sampling, soil sample analysis, data evaluation, suggestion of contaminated farmland control, and analysis of potential pollution sources and transfer routes. 2,251 soil samples,had been sampled from Chang-Hwa County, Yun-Lin County, Nan-Tao County, and Chia-Yi City, and been analyzed in this project. 44% of these samples concentration exceed the soil pollution control standard (Table 1), including 492 farmlands (125.65 ha registered) with total contaminated farming area of 108.38 ha in Chang-Hwa, and 6 farmlands (0.39 ha registered) with total contaminated farming area of 0.39 ha in Nan-Tao County. However, the concentration of samples from Ynu-Lin County and Chia-Yi City do not exceed the soil pollution control standard. To coordinate with the investigation results of the relative project regarding to water and sediment quality of irrigation channels in Chang-Hwa area, the pollution sources are preliminary concluded to be the irrigation channels surrounding the farmlands in Chang-Hwa area. As to the Nan-Tao County, the abandoned brick furnace plants neighboring the farmland are suspected to be The pollution sources. The results show that the soil of the investigation area in Chang-Hwa County is the most polluted. Base on the Geostatistics study and the distribution of the irrigation channels; the area neighboring the investigated farmland in this project is suspected being polluted. For the farmlands exceeding soil control standard, Geostatistics method is suggested to coordinate with the information of the irrigation system to clarify the contaminated area so as to be the basis of land control and remediation work. As to the farmlands, not being investigated in this project but with high pollution potential according to the Geostatistics study, detail investigations are suggested. Regarding to soil pollution remediation, it is suggested to coordinate with the effluent control and irrigation channel remediation to achieve an all-out success.

Two of the main features of today complex software systems like pervasive computing systems and Internet-based applications are distribution and openness. Distribution revolves around three orthogonal dimensions: (i) distribution of control|systems are characterised by several independent computational entities and devices, each representing an autonomous and proactive locus of control; (ii) spatial distribution|entities and devices are physically distributed and connected in a global (such as the Internet) or local network; and (iii) temporal distribution|interacting system components come and go over time, and are not required to be available for interaction at the same time. Openness deals with the heterogeneity and dynamism of system components: complex computational systems are open to the integration of diverse components, heterogeneous in terms of architecture and technology, and are dynamic since they allow components to be updated, added, or removed while the system is running. The engineering of open and distributed computational systems mandates for the adoption of a software infrastructure whose underlying model and technology could provide the required level of uncoupling among system components. This is the main motivation behind current research trends in the area of coordination middleware to exploit tuple-based coordination models in the engineering of complex software systems, since they intrinsically provide coordinated components with communication uncoupling and further details in the references therein. An additional daunting challenge for tuple-based models comes from knowledge-intensive application scenarios, namely, scenarios where most of the activities are based on knowledge in some form|and where knowledge becomes the prominent means by which systems get coordinated. Handling knowledge in tuple-based systems induces problems in terms of syntax - e.g., two tuples containing the same data may not match due to differences in the tuple structure - and (mostly) of semantics|e.g., two tuples representing the same information may not match based on a dierent syntax adopted. Till now, the problem has been faced by exploiting tuple-based coordination within a middleware for knowledge intensive environments: e.g., experiments with tuple-based coordination within a Semantic Web middleware (surveys analogous approaches). However, they appear to be designed to tackle the design of coordination for specic application contexts like Semantic Web and Semantic Web Services, and they result in a rather involved extension of the tuple space model. The main goal of this thesis was to conceive a more general approach to semantic coordination. In particular, it was developed the model and technology of semantic tuple centres. It is adopted the tuple centre model as main coordination abstraction to manage system interactions. A tuple centre can be seen as a programmable tuple space, i.e. an extension of a Linda tuple space, where the behaviour of the tuple space can be programmed so as to react to interaction events. By encapsulating coordination laws within coordination media, tuple centres promote coordination uncoupling among coordinated components. Then, the tuple centre model was semantically enriched: a main design choice in this work was to try not to completely redesign the existing syntactic tuple space model, but rather provide a smooth extension that { although supporting semantic reasoning { keep the simplicity of tuple and tuple matching as easier as possible. By encapsulating the semantic representation of the domain of discourse within coordination media, semantic tuple centres promote semantic uncoupling among coordinated components. The main contributions of the thesis are: (i) the design of the semantic tuple centre model; (ii) the implementation and evaluation of the model based on an existent coordination infrastructure; (iii) a view of the application scenarios in which semantic tuple centres seem to be suitable as coordination media.

Extended reach well directional drilling technology has been widely applied for the efficient development of oil and gas resources in complex areas such as oceans, beaches, lakes and mountains. However, there are many challenges in extended-reach drilling, and there are multiple constraints, which include huge technical difficulties and high risks, which make the prediction and control of wellbore extension limit of great importance for safe drilling. On the basis of summarizing research progress on the extension limit of extended reach wells at home and abroad, the prediction model and distribution law of the extension limit were introduced. Also, a extension limit-based extended reach well optimal drilling design was proposed, and such extension limit theory was used to analyze the rotary drilling limits and completion string entry limits in the horizontal section of the Z–42 extended reach well in Sakhalin area. It was considered that the hoisting performance of drilling rig could greatly improve the wellbore extension limit, and the installation of rotary joint and drag reducer joints could increase the entry limit of the completion string. The research results showed that those prediction theories and control methods could provide scientific references and best practices for risk prediction, optimized design and safety control of extended reach well drilling.

Pusarpedal-KLH monitored Lead (Pb) concentration in Serpong area from 2001 – 2004. The result was around 0.5-6 μg/m3 and average was 2.51 μg/m3 exceeded national ambient air quality standard (PP 41/1999), for 24 hour that is 2μg/m3 and also for annual that is 1 μg/m3. The present condition of the high concentration of Pb in Serpong area was verified by the conducted measurement at 10 (ten) sampling points at around Puspiptek area, kec. Serpong, Kec.Pagedangan Kec Pamulang, dan Kec. Gunung Sindur on January to February 2006. The result obtained was exceeded national ambient air standard at SD Setu Muncul (Pb concentration: 6.03 μg/m3), Batan Indah (Pb concentration: 3.79 μg/m3) and BSD Griya Loka (Pb concentration: 2.1 μg/m3). The Pb concentration in elementary school children blood was also monitored in Serpong and its surroundings. As result, Pb concentration in elementary school children blood Serpong elementary school children blood was ranged from 7-12 μg/dl, with average concentration; SDN Setu 01 = 12.0μg/dl, SDN Puspiptek = 9.5 μg/dl), SDN Kademangan = 7.1 μg/dl, and SDN Batan = 7.5 μg/dl. The Pb concentration in elementary school children blood in Jakarta area was ranged from 2.1 - 6.1 μg/dl. Standard specified by Center for Disease Control and Prevention (CDCP)-USA is: 10 μg/dl. The evaluations of meteorological data and emission source have been conducted, in order to understand the air pollution situation in Serpong area. Frequency distribution of wind speed and wind direction was calculated and conclude that 50-60% was calm condition, and the emission sources at Serpong and its surroundings in radius 30 s/d 40 km.

Soil erosion considered as one of the most important obstacles in the way of sustainable development of agriculture and natural resources. In Ethiopia, soil erosion is a serious problem. The studies on erosion risk in the watershed show a trend towards increasing land use, accelerating erosion in the study area. The influencing factor for the give watershed are the land use, the elevation, the slope, TWI, SPI, and soil. This study focus to determine and mapping the hotspot areas to erosion of rib watershed with an area of 1174.7 km2. The sensitivity area for erosion was done by a multi-criteria decision evaluation method with parameters of influencing factors. The analysis of the maps using GIS analysis tools for different criteria which shows that the findings vary from one criterion to another. Considering all criteria, the finally obtained map shows that the areas with a high, moderate, low and very low vulnerability to erosion are 1.13%, 8.11%, 88.34% and 2.42% respectively in the given watershed. Overall, the soil erosion changes analysis and mapping as well as its distribution is effective and important for identifying natural resource prone areas. Therefore, the local experts and administrative bodies uses this information to prepare plan for those priority areas to conserve and monitor the degraded resources.

The demonstration area of ecologically friendly development in the Yangtze River Delta is a major national strategy area, and thus eco-environmental protection should be a priority for the sustainable development. Exploring the spatial-temporal variations of franctional vegetation coverage (FVC) is conducive to accurate assessing the ecological quality of environment, which is of great significance to regional sustainable development. In this study, the characteristics and trends of spatial-temporal variation of vegetation cover during 1984-2019 in the demonstration area were analyzed based on Google Earth Engine (GEE). The effects of different ecological factors on FVC were quantified by the boosted regression tree (BRT). Results showed that,the changing trend of FVC in the study area shifted from decreasing to increasing trend from 1984 to 2019. The spatial distribution of FVC in the study area varied with both stages and regions. FVC was mainly degraded. Compared with the year 1984, the area of vegetation degradation and improvement in 2019 accounted for 49.8% and 12.8%, respectively. The vegetation degradation mainly occurred in the north of Wujiang, south of Jiashan, and northeast of Qingpu. Human activities severely weakened the influence of natural factors on FVC. Our findings suggested that the GEE is an effective tool for monitoring the dynamics of vegetation coverage.

Backgrounds. The placement of dental implants is restricted by various anatomic limitations such as an insufficient residual ridge height. Cantilever extensions in implant-supported prosthetic partial dentures may result in unfavorable loading on the abutment fixtures. Adjunct support of the distal cantilever partial denture by a short implant at distal extension area may reduce the overloading on the dental abutment implants. Purpose. To examine the stress distribution on an additional short implant at different location of a distal cantilever prosthesis. Material and methods. Two 10 mm and one 6mm titanium rods resemble the regular osseointegrated dental implant were embedded in the resin block. The short 6mm titanium rod was used to support the distal cantilever extension of the prosthesis. Three different distances between the regular and short titanium rods (10, 16, 22 mm) were established and were tested the strain around all the titanium rods when 400N loading force directly applied on the titanium rod at presumed first molar position. Results. Introducing an adjunct short implant to support the cantilever segment of a prosthesis can significantly reduce the strain around all implants (P＜0.05). When the short implant was placed at 22mm distal to the distal regular implant, the applied force can be even distributed. Conclusion. Assisting support a short implant at distal extension area can reduce the unfavorable cantilever effect on the cantilever prosthesis.

Solid fuels play an important role in modern day supply of energy and chemicals. Coal, is available in abundance and is therefore still an important source of energy. Waste contains a large amount of organic matter and can therefore be used as a solid fuel. Waste-to-energy is a popular theme world-wide. Biomass is, under certain conditions, a sustainable solid fuel and may thus be one of the most important sources of energy and chemicals for the future. The study of the thermal conversion of solid fuels is therefore relevant to many processes and applications. Fuels like biomass or municipal solid waste are quite inhomogeneous. Their composition and heating value may vary substantially even within a single batch. The uidised bed technology is an e??cient and exible method to use such inhomogeneous fuels. Such fuels are therefore often converted in uidised beds. The fuel is introduced into the uidised bed in the form of particles. The whimsical nature of the fuel causes a constant disturbance to the uidised bed and thus to the equipment that relies on the output of the uidised bed. A control system must suppress the uctuations in the output of the uidised to secure the optimal operation of the equipment downstream. In order to do so successfully, a thorough understanding of the dynamics of the thermal conversion of particles is necessary. That is the subject of this thesis. The thermal conversion of solid particles usually occurs in an apparatus where many particles convert simultaneously. The total gas or heat production of all particles together constitutes the behaviour of the system. If there are enough particles, it is not necessary to account for the behaviour of every individual particle to predict the behaviour of the system as a whole. Due to the large amount of particles, it is su??cient to know the averaged behaviour over all particles. One may directly derive equations for this average that do not depend on the individual particles in the system. This can be done using a population balance equation. This equation describes the expected distribution of particles over space and over the relevant particle properties. Suppose the gas or heat production of a single particle is known as a function of the particle properties and the external condition (e.g. temperature). In that case the total gas or heat production in the apparatus can be calculated by integrating that function, weighted with the expected particle distribution. There are thus two main issues to be resolved in order to model the dynamics of a system in which particles are converted under the in uence of heat: 1. The behaviour in time of a single particle must be expressed as a function of the relevant particle properties and the external conditions. 2. The population balance equation must be established and solved to calculate the expected particle distribution. Both issues are addressed in this thesis. The population balance is subsequently used in a model of a circulating uidised gasi??er. The ??nal chapter of this thesis concerns the problem of tar in biomass gasi??cation. The thermal conversion of a single particle consists of several processes: drying, pyrolysis, gasi??cation and combustion. There exist good descriptions of the single particle behaviour for gasi??cation and combustion. There is no good solution for the behaviour of particle during drying and pyrolysis yet. Therefore, pyrolysis is studied in this thesis. Drying is discussed when the results of experiments are presented. New method to measure reactivity To study the behaviour of biomass particles under uidised bed conditions, a new measurement method has been developed. The method consists of a heated uidised bed placed on a balance. A batch of biomass particles is dropped into the bed. The mass decrease of these particles in the bed can be monitored using the balance. Nitrogen is used as uidising medium, so that the pyrolysis process can be observed without subsequent combustion or gasi??cation of the particles. The uidised bed causes large weight uctuations on the balance. Therefore signal processing is necessary to extract the mass decrease of the biomass particles from the signal. Two types of signal processing have been tested: a linear and a non-linear ??lter. The linear ??lter is a low-pass ??lter that attempts to separate the high frequency uidised bed noise from the low frequency mass decrease of the biomass. This ??lter exploits the fact that one knows that the mass decrease must be much slower than the weight uctuations due to the uidised bed. The non-linear ??lter is a wavelet ??lter with thresholding. This ??lter exploits the fact that one expects the mass decrease to be much smoother than the uidised bed noise. The noise can then be estimated and subtracted from the signal. The wavelet thresholding ??lter proves to be more successful for two reasons: ??rstly the ??ltered signal is smoother and leads to more reproducible results (especially of the pyrolysis time) and secondly the method allows for a more concise statement of the assumptions and approximations involved. The measurement results show that the pyrolysis time depends almost linearly on the particle diameter. This leads to the conclusion that the activation energy of the pyrolysis reaction must be relatively low, and thus lower than is usually assumed. The measurements also showed that the pyrolysis time may depend linearly on moisture content. This suggests that drying is determined solely by the external heating rate. However, the measurements also leave room for the interpretation that the presence of moisture leads to a more or less constant increase in pyrolysis time. This suggests that pyrolysis will start before drying is complete. The measurements are inconclusive in this respect and further research into drying is recommended. Pyrolysis model A physical and mathematical model of biomass pyrolysis has been developed to determine which particle properties are essential to the pyrolysis behaviour of a single particle. The development starts with a derivation of the equations that are generally used to describe biomass pyrolysis. The derivation shows which assumptions are implied by the equations that are commonly used. One of the most important assumptions is that the pyrolysis reaction rate depends linearly on the concentration of fresh biomass. It is in fact more likely that the reaction rate depends linearly on the internal surface area of fresh biomass. The implied assumption is therefore that the internal surface area depends linearly on the biomass concentration. This assumption is hardly justi??ed. An investigation of the biomass structure and of the actual reaction order is recommended. It is also shown that there are two groups of kinetic parameters to be found in literature. Between these groups the proposed activation energy of the pyrolysis reaction di??ers by a factor two (approximately). The groups di??er in the way in which the kinetic parameters are determined. Fitting of the kinetic parameters using a model that incorporates heat transfer and the pyrolysis reaction leads to the lower activation energy while TGA measurements lead to a higher activation energy. It is shown in this thesis that the lower activation energy leads to better results. The TGA experiments rely on the assumption that the external heat transfer to the samples was not rate limiting during the experiments. This assumption can, however, only be veri??ed if the reaction kinetics are already known. If the reaction kinetics are derived from TGA experiments under the false assumption that external heat transfer is not rate limiting, then the activation energy will be overestimated. A simpli??ed analytical solution to the pyrolysis equations has been derived in this thesis. This solution is shown to describe the experiments quite well. The main particle properties that determine its pyrolysis behaviour are found to be: particle diameter, type of fuel, initial moisture content and the initial density Population balance The nature and the derivation of the population balance equations are discussed in detail. The analytical solution for the population balance equation is obtained, but is found to be of little use for anyone who wants to understand the behaviour of the system in which the particles are converted under the in uence of heat. Therefore, the population balance equation is rewritten in terms of moments of the particle properties. Examples of these moments are average diameter, variance of diameter etc. This led to signi??cant insight in the behaviour of a CFB gasi??er. The main conclusion is that average particle size is insu??cient to characterise the speed at which the gasi??er responds. The variance of particle size is very important too. If the particle distribution of e.g. size is broader, the gasi??er will respond to changes with a larger uctuation in gas production and gas quality. At the same time it will recuperate slower. Changes of average particle size in the feed lead naturally to a broader particle distribution. The e??ect of changes in particle size is much larger than the e??ect of changes in moisture content. Gasi??er model The population balance is applied in a model for a CFB biomass gasi??er. This model is designed in such a way that it will be straightforward to incorporate new insights and results in areas where the present research has not focused, such as tar conversion, char gasi??cation and drying. Simulations with the model show that the particle size has a much more profound e??ect on the gasi??er than the fuel moisture content.

Debris flows triggered by earthquakes are recognized globally for their huge destructive power. Studies on the development features of debris flow are essential for disaster prevention and mitigation and the results can be used as a scientific basis for assuring public security, preventing debris-flow disasters and reconstructing the afflicted areas by earthquake. Taking the, Niujuan Gully, as the case study area, this paper discusses field observations of the initiation and path of debris flows in the epicentral area of the 12 May, 2008 Wenchuan Earthquake. Based on the natural conditions and debris flow distribution in the study area, a field control network was established to monitor the gully bed, typical slopes and channel sections of different kinds of debris flows that initiated from hillslopes and gullies. We observed debris flows and their change under different rainfall circumstances, surveyed slope, section, channel and gully bed by means of GPS, GPT-3002 total-station instrument and 3D laser scanning system and drew digital topographic maps, sectional maps and profile maps with a 1:50 scale. Based on the observed data, we probed into the erosion laws and development features(including erosion, transportation, deposition, etc) of different kinds of debris flows and analyzed debris flow discharge, erosion-deposition variation and destructive magnitude. The findings provided data support for debris flow risk assessment and monitoring systems.

The power system for the on-detector electronics of the CMS Experiment comprises approximately 12000 low voltage channels, with a total power requirement of 1.1 MVA. The radiation environment inside the CMS experimental cavern combined with an ambient magnetic field (reaching up to 1.3 kGauss at the detector periphery) severely limit the available choices of low voltage supplies, effectively ruling out the use of commercial off-the-shelf DC power supplies. Typical current requirements at the CMS detector front end range from 1A-30A per channel at voltages ranging between 1.25V and 8V. This requires in turn that the final stage of the low voltage power supply be located on the detector periphery. Power to the CMS front-end electronics is stabilized by a 2 MVA uninterruptible power supply (UPS) located in a CMS surface building. This UPS isolates the CMS detector from disturbances on the local power grid and provides for 2 minutes of autonomy following a power failure, allowing for an orderly shutdown of detector electronics and controls. This paper describes the design of the CMS Detector Power System, reviews the process of its installation and commissioning, and discusses issues of power distribution common to current-generation collider detectors. I. OVERVIEW OF THE CMS DETECTOR CMS is a general-purpose detector at the LHC accelerator at the CERN laboratory in Geneva, Switzerland. A description of this detector is beyond the scope of this paper, but may be found in reference [1]. A. Requirements of CMS Detector The front-end electronics of the CMS detector has 12090 low-voltage channels, requiring 1182 KVA of power. The steel yoke structure of the CMS detector serves as a flux return for the 4-Tesla solenoid inside the detector structure. Since the magnetic field of the solenoid is large enough to drive sections of this steel yoke into saturation there is an ambient magnetic field that can reach up to 1.3 KG outside detector in the regions where low voltage power supplies are mounted. Typical commercial low-voltage power supplies are not designed for operation in a magnetic field and many have been noted to fail destructively at fields above 150 Gauss. In addition, the high radiation environment inside the CMS experimental cavern imposes constraints on the design of low voltage supplies from the standpoint of semiconductor displacement damage and single-event effects. Together, these constraints rule out the use of general-purpose commercial power supplies. Typical front-end current requirements are 1 to 30A per channel, at voltages from 1.25 to 8.0V. Since cable power dissipation must be kept within reasonable limits, the placement of the final power supply stage is constrained to be within ~10m of the front-end electronics, that is, on the detector periphery. B. CMS power distribution requirements The power cable paths between CMS on-detector systems and the power distribution area in the adjacent equipment cavern are typically 100 to 140m in length. Power to the detector is supplied at 380 and 230 VAC (three-phase) and at 385 VDC. No neutral is distributed. The CMS detector power system serves all of the low voltage power needs on the detector from a single distribution network. Although there are other power distribution networks at the CMS site, there are no persistent connections between the CMS detector and any of these other networks. This single-source powering scheme enables a unified earthing structure for the CMS detector and simplifies considerations of detector response to disturbances in power distribution. C. CMS power distribution system architecture The detector power system is powered by a 2 MVA uninterruptible power supply (UPS) installed on the surface. The UPS provides for at least 2 minutes autonomy in the event of a power failure. This length of time is sufficient to provide for an orderly shutdown of subdetector power systems. The UPS powers a bank of 6 isolation transformers located underground in one of the CMS caverns. The transformers are apportioned by subdetector and geographical detector region. Each transformer feeds one or more power distribution cabinets containing circuit breakers, monitoring equipment and programmable logic controllers. Power from an individual circuit breaker channel can be turned on and off via a remote control system, but in the event of a fault condition the circuit breaker must be reset manually. This is a deliberate design choice to prevent casual responses to fault conditions. The isolation transformers consist of four 230V and two 380V three-phase units, each containing an interwinding electrostatic screen. Static compensators are connected to selected distribution cabinets in order to provide power factor correction (PFC) for certain subdetectors (Fig 1.)

هدف از پژوهش کنونی بررسی دورنمایی از اثرات احتمالی تغییر اقلیم بر جابه‌جایی زمانی تاریخ وقوع اولین و آخرین یخبندان‌های پاییزه و بهارۀ ایران است. بدین منظور از داده‌های دیده‌بانی 43 ایستگاه همدید کشور (1981-2010) و داده‌های شبیه‌سازی شدۀ LARS WG در دو مدل آب‌وهوای جهانی GFCM21 و HadCM3 در بازه‌های زمانی (2065-2046) و (2099-2080)، تحت سه سناریوی انتشار A1B، A2 و B1استفاده گردید. نتایج، بیانگر جابه‌جایی اولین یخبندان پاییزه‌ به سمت اوایل زمستان و جابه‌جایی آخرین یخبندان بهاره به‌سوی اواخر زمستان در گسترۀ ایران است. پراکنش زمانی-مکانی تغییرات متفاوت است؛ به‌گونه‌ای که بیشترین جابه‌جایی‌های مثبت در رخداد اولین یخبندان پاییزه در دورۀ (2065-2046) در ایستگاه‌هایی چون خرم‌‌آباد، رشت و گرگان مشاهده می‌شود. میزان تغییرات در ایستگاه‌های شمال شرقی (سبزوار و سمنان)، نیمۀ جنوبی (کرمان، بم و آباده) و بیشتر ایستگاه‌های شمال‌غرب نسبت به دیگر مناطق کمتر است. در دورۀ (2080-2099) بیشترین روند منفی در ایستگاه‌های گرگان، رشت، اردبیل و شهرکرد خواهد بود. خوی، قزوین، بم و کاشان کمترین جابه‌جایی منفی خواهند داشت.