Resistivity

The photolithography process is one of the most complex operations in semiconductor production. Exposure energy definition is particularly critical because it strongly affects the operation results. Very complex links exist between exposure energy, pattern critical dimensions, photo resist thickness, and resistivity. At present, the wafer test experimental procedure is used in order to define suitable exposure energy. With the aim of finding a less expensive control criterion of exposure operation in the photolithography process, a neural network has been developed that is able to model the relation between exposure energy and pattern dimensions measured in different positions on the wafer. As a result, the neural network model developed has been found to perform as well as the very expensive test wafer procedure and constitutes a good alternative to this one, allowing for a remarkable cost reduction

Detection of unmarked burials with geophysical methods of survey have had mixed results in the past, both in the archaeological domain as in the forensic science domain. Each method has shown several limitations on their own. The application of multiple methods on a single site has been investigated on three different sites in order to evaluate the effectiveness of interpreting multiple datasets against each other to locate unmarked burials. The sites selected offered relatively known locations for possible burials, allowing for easier verification whether a possible burial was detected. The interpretation of these multiple datasets has shown that it provides a higher degree of confidence when interpreting possible burial locations, as opposed to relying on a single interpretation.

The MT interpretation procedure begins with a set of sounding data in the frequency domain. The overall quality of these data can be variable both as a function of frequency and location. Many simple interpretation procedures, such as the assessment of static distortion, act directly on the sounding data. A number of response characteristics, such as the location (in frequency) and number of turning points, are important to the interpretation. Localised scatter (noise) in the response estimates can produce false gradients which degrade the quality of the inferences made from the data. This study considers how the D + solution can be used to process the raw sounding data to provide a number of interpretational advantages. Although the D + solution has strict formal roots in 1D inverse theory, it is used here simply to enhance those data attributes, particularly that of physical validity, which lead to a more meaningful assessment of data characteristics. The data considered are 84 broadband array soundings from the Paraná basin, Brazil. The advantages provided by the D + processed data set are demonstrated by using the raw and processed data in two main interpretational procedures. The first procedure concerns the ability of the data to provide quantitative assessments of the influence of static distortion. The second procedure concerns the application of transform methods which attempt to recover a resistivity/depth or reflectivity profile directly from the sounding data.

Groundwater is one of natural resources that serves to support life and development activities. Utilization of water increasingly increasing day along wi th the increasing rate of population growth and development of a region. The investigation of groundwater around Mount Batur, Jepitu Village, Gunungkidul Regency needs to be done because the allotment o ther than as the d aily needs of the surrounding population, the area is also included in the tourism development area of Gunungkidul Regency by UNESCO. In order to support this, the investigation through the ground or underground should be done in order to kno w the presence or absence of water carrier layer (aquifer), thickness, and depth. The investigation that can be done is through geoelectric method and mapping of underground river system. Geoelectric detection is carried out on the basis of the physical properties of rocks against electric currents, where each different roc k will have different types of resistance. While underground river mapping aims to determine the pattern of underground river flo w. The objective of the research is to integrate geolistrik method data of schlumberger configuration of sounding type and underground river mapping data to find out the soil water layer, thickness, and depth. The result will show a predicted subsurface vertical resistivity sec tion as soil layers or water-saturated rocks. The focus of the telitian is on 16 geo-electric tracks and 6 underground river systems which at that point are made of a configuration incision as well as the hydrostratigraph of the West-East and North-South direction. From the mapping of underground river system, there are 3 caves that are very potential in terms of quantity, namely cave puluaajar, cave sumurup, and curing cave. The prediction of the aquifer potential layer is at a depth of 10-100 m with a resistivity value 12-0 Ω.

Telah dilakukan penelitian untuk mengidentifikasi keberadaan zona prospek mineral logam menggunakan metode Induksi Polarisasi pada daerah Fatunisuan, Kecamatan Miomaffo Barat, Provinsi Nusa Tenggara Timur. Metode induksi polarisasi merupakan salah satu bagian dari geolistrik yang sering digunakan dalam eksplorasi mineral logam.
Lintasan yang digunakan dalam penelitian ini berjumlah 12 lintasan pengukuran dengan arah lintasan N 55° E (Barat daya-Timur laut). Panjang lintasan rata-rata 2000 meter dengan spasi pengukuran 20 meter dengan faktor pengali kedalaman (n) 8. Konfigurasi yang digunakan dalam pengambilan data adalah konfigurasi Dipole-Dipole.
Berdasarkan pengukuran metode induksi polarisasi, mineral logam pada daerah penelitian memiliki nilai Chargeability > 60 Msec dengan korelasi nilai Resistivity sedang-tinggi dengan range nilai 80-250 Ohm.m. Dari sebaran anomali IP, posisi mineral logam pada daerah penelitian menyebar secara setempat, pola kemererusannya terlihat terkonsentrasi pada daerah lembah dan lereng bukit. Mineral logam pada daerah penelitian merupakan jenis endapan skarn.
Zona prospek mineral logam pada daerah penelitian ini dibagi menjadi tujuh zona, dimana masing masing zona memiliki karakteristik yang relatif sama. Berdasarkan hasil interpretasi penyebaran mineral logam cenderung berarah utara-selatan dengan luasan zona bervariasi antara 0,5 sampai 3,3 hektar. Berdasarkan sebaran zona target didapatkan 16 titik rekomendasi titik pemboran guna memastikan jenis mineral logam yang terdapat pada daerah penelitian.

A pre-requisite in slope stability analyses is that the internal structure and the mechanical properties of the soil or rock mass of the slope, are known or can be estimated with a reasonable degree of certainty. Geophysical methods to determine the internal structure of a soil or rock mass may be used for this purpose. Various geophysical methods and their merits for slope stability analyses are discussed. Seismic methods are often the most suitable because the measurements depend on the mechanical properties that are also important in the mechanical calculation of slope stability
analyses. Other geophysical methods, such as electromagnetic, electric resistivity, self-potential, and gravity methods, may be useful to determine the internal structure, but require a correlation of found boundaries with mechanical properties.

Abstract
The objective of this geophysical survey is to evaluate the hydrological characteristics of the study area. This includes the availability of groundwater, depth of aquifer, determining whether the underlying geology is competent basement/weathered basement or fractured bedrock and the delineation of the subsurface into various geo-electric layers. The availability of groundwater in an area is controlled by varying geological factors such as hydrogeological units, stratigraphical faults/folds, and geological sequences
The methodology used is the direct current method using the schlumberger configuration. In this electrical resistivity method, artificially-generated electric currents are introduced into the ground and the resulting potential differences are measured at the surface. Deviations from the expected pattern of potential differences from homogeneous ground provide information on the lithological formations and electrical properties of subsurface anomalies. A total of 10 vertical electric sounding was carried out on the study area, which covers the entire community and the data plotted and computer software designed by Vander Velpen BPA was used to iterate the result. This removes the noise and field errors incorporated in the data. The result of the VES curve reveals that there are three major geoelectric layers
The fist layer has an intermediate resistivity implying a sandy soil. Very low resistivity corresponds to clayey/clayey sand (VES 4, VES 5, and VES 6) while exceedingly high resistivity (VES 10) implies a lateritic cover. The second layer is the weathered layer sub-divided into minor geoelectric layers such as clays, gravels and weathered rocks. The weathered layers have low resistivity values, possibly due to the presence of conduction fluids such as water. The third layer is the basement or bedrock which may be fractured basement or fresh bedrock. Ajaokuta has more of fresh unfractured bedrocks except in some cases (VES 2 and VES 4)
The resistivity of topsoil varies from 12.6Ω to 3247.9Ω with a mean of 657.1Ω ± 947.7. The thickness of topsoil is within the range of 0.4m to 14.9m with a mean of 2.2m ± 4.2. The resistivity of weathered layer ranges from 27.9Ω to 175.5Ω with a mean of 59.2Ω ± 43.5. The thickness of the weathered layer is from minimum of 5.8m to maximum of 37.0 m having a mean of 12.4m ± 9.5. The depth to basement varies from 6.2m to 37.5m with a mean of 13.38 ± 9.07. The resistivity of the basement in the area varies from 183.3Ωm to 4294.2Ωm with a mean 0f 905Ωm ± 1170.The thickness of the topsoil is very low except for (VES 4) The average depth to basement is 13.38m±9.07.
Keywords: Boreholes, Ajaokuta, schlumberger configuration, resistivity, VES

1.  Berdasarkan anomalli magnetic dari data diatas, memungkinkan  bahwa pada daerah pengukuran terdapat satu bodi, terlihat dari nilai magnetic yang rendah negtif dan yang tinggi positif, diperkirakan di daerah ini batuan tersebut  yang berupa batuan beku
2. Data gravity tidak dapat dilakukan interpretasi karena banyak factor yang mempengaruhi sehingga kualitas data berkuang. Terlihat dari nilai densitas yang sangat tinggi.
3. Pada data resistivity dan IP setelah dilkukan pemodelan, maka diidentifikasi bahwa pada deaerah pengkuran terdapat batuan sdimen yang didalamnya terdapat Fluida, hal ini juga dipengaruhi oleh lokasi pengukuran yang terletak di dekat danau.

Video presentation of Historical and archaeological investigations of 33Wo50 excavated in 1977 revealed the archaeological remains of the Amos Spafford Farm-House (1810-1812) at Port Miami, Michigan Territory. The house was plundered, burnt, and destroyed on August 21, 1812 by a party of British and Indians from Fort Malden, Canada. During this raid Shawnee chief Tecumseh led the Indians, while British Captain Peter Latouche Chambers, 41st Regiment of Foot led the British contingent.

Salt water intrusions of marine origin are a major cause of contamination for coastal fresh water aquifers. They are generated mainly by the uncontrolled exploitation of fresh water in pumping stations from coastal areas. In Romania, such marine intrusions have occurred in the southern part of Black Sea's coastline, in the area of Vama Veche and Costineşti resorts, contaminating the main aquifers which are hosted within Sarmatian (late Middle Miocene) lumachelic and oolitic limestones. Fresh water exploitation management requires the identification, mapping and monitoring of marine intrusions. These are achievable by means of an adequate application of geoelectrical methods, because sea water intrusions lead to major variations of the aquifers resistivity. Apparent resistivity surveys such as electrical profiling and vertical electrical sounding (VES) are able to delineate the areal extent of these intrusions and to identify the approximate depth of the fresh water/salt water interface. Assuming the subsurface geology consists of horizontal and homogeneous layers, the VES apparent resistivity data can be interpreted in terms of layer thicknesses and true resistivities, i.e. a one-dimensional (1-D) geoelectrical model with a stepwise variation of true resistivity with depth. The optimal model is obtained by repeated forward modeling trials or through the inversion of measured apparent resistivities.
This paper presents an algorithm and a set of software applications for the forward modeling of VES apparent resistivity curves, by using digital linear filtering. The codes were elaborated in MATLAB programming environment and allow the calculation of the theoretical VES response for horizontally-layered geological media with virtually unlimited number of layers, including layers with a quasi-continuous resistivity variation. The latter option can be used to simulate particular hydrogeological situations regarding the sea water intrusions in fresh water aquifers, which often show a mixing/transition zone of variable salinity and resistivity. The interpretation of VES curves recorded in Vama Veche area by using the elaborated software indicates that the sea water intrusion occurs at more than 50 m depth. This agrees with water wells tests which confirm the presence of salt water at 40–60 m depth in that area.

A term first coined by Mott back in 1968 a “pseudogap” is the depletion of the electronic density of states at the Fermi level, and pseudogaps have been observed in many systems. However, since the discovery of the high-temperature superconductors (HTSC) in 1986, the central role attributed to the pseudogap in these systems has meant that by many researchers now associate the term pseudogap exclusively with the HTSC phenomenon. Recently, the problem has got a lot of new attention with the rediscovery of two distinct energy scales (“two-gap scenario”) and charge density waves patterns in the cuprates. Despite many excellent reviews on the pseudogap phenomenon in HTSC, published from its very discovery up to now, the mechanism of the pseudogap and its relation to superconductivity are still open questions. The present review represents a contribution dealing with the pseudogap, focusing on results from angle resolved photoemission spectroscopy (ARPES) and ends up with the conclusion that the pseudogap in cuprates is a complex phenomenon which includes at least three different “intertwined” orders: spin and charge density waves and preformed pairs, which appears in different parts of the phase diagram. The density waves in cuprates are competing to superconductivity for the electronic states but, on the other hand, should drive the electronic structure to vicinity of Lifshitz transition, that could be a key similarity between the superconducting cuprates and iron-based superconductors. One may also note that since the pseudogap in cuprates has multiple origins there is no need to recoin the term suggested by Mott.

On the 27 November 2015, our ARC-funded Lake George Project* arrived at a milestone, when the first core appeared from the direction of the high-tech sonic drill rig, perched above a surveying mark on the bed of mysterious Lake George, or, to use its traditional name, Weereewa. A team of drillers, surpassed in number by a team of scientists, excitedly started to package the fresh core, to keep it from sunlight in anticipation of OSL dating, some months away. The wind turbines in the background were slowly rotating, but the puddles on the on the lake floor hadn’t dried up yet, so on this early morning everyone felt lucky, for one reason or another.

A simple filter is developed which transforms VLF-EM real magnetic field transfer functions into apparent resistivities. It is based on the relationship between the horizontal derivative of the surface electric field and the vertical magnetic field at the surface of a two-dimensional earth model. The performance of this simple autoregressive filter is tested for modelled and real survey data. The technique yields profiles of apparent resistivity very similar, both in magnitude and in wavelength, to those which would have been obtained using VLF-EM resistivity measurements or d.c. resistivity profiling. This low-pass filter has the advantage of reducing high-wavenumber noise in the data; therefore only the major features of the VLF-EM profile are displayed.

The electrical resistivity of the subsurface was measured along a 400m line up to 60m deep in the Majors Creek area, southeastern New South Wales. Manual auger samples, collected up to 250cm depth, were analysed using X-Ray powder diffractometry, to characterise the resistivity anomalies. Particular attention was paid to the geophysical inversion method and to the identification and quantification of minerals in auger samples. The smoothness-constrained least-squares optimisation method produced a modelled resistivity bounded between 20 and 600 Ωm, with a vertical discontinuity at depth (~15m and downwards) near the middle of the pseudosection, and a clear delimitation of groundwater in the first 15m below the surface. The regularly sampled subsurface was made up of in-situ weathering products, comprising mottled clays and moderately weathered saprolite of felsic igneous rock with preserved granitic texture. The effect of weathering was found to override all the other trends in the mineral quantification, correlating zones of water storage and mottling with high clays and amorphous content and low plagioclase, micas, magnetite and, in a lesser extent, low K-feldspar and inversely in dryer area, for relatively constant quartz. The nature of the deep resistive discontinuity could be the result of a conductive/resistive dyke or a local fault, interpretations that are supported by previously published geological map and aeromagnetic data, but for which the auger samples are of little use.

The measurement of the soil’s electrical resistivity offers the possibility in the first place to define the various horizons of the ‟Sikha landslide”, in the Souk Larbâa de Bni Hessan locality (Northern Morocco) and also to spatialize the variation of the humidity on the slipped mass. The Investigations of the ‟Sikha landslide” was done by collecting data of 19 electrical tomography profiles, this allowed us to collect the spatial distribution of the resistivity values in the underground. The processing of these data by the Res2Dinv software, allowed us to build pseudo-sections by the inversion methods, there from the resistivity indicated in these sections can well define both horizons. The marly bedrock of the Tangier unit with a resistivity superior to 169 Ohm.m and the slide mass which is characterized by a lower resistivity than 33,3 Ohm.m, in this mass we could find more resistive blocks than their matrix, corresponding to siliceous boulders and marls with limestones levels. The determination is obtained by treatment and analysis of the pseudo-sections of the 19 achieved profiles, taking into account the contrasted resistivity values in the elaborated pseudo-sections. This technique allowed us to determine the depth of the detachment boundary between the horizons, which is fluctuating in the landslide area. In the upstream zone, it reaches 20 meters. In the creeping movement zone, the thickness of the mass varies between 10 and 30 meters and in the downstream zone, the depth of the detachment level is between 15 and 25 meters.

Vitreous coatings can be used as a means for the corrosion protection of metals and alloys due to their excellent dielectric properties. Their use is of particular interest in the case of highly aggressive media (different pH levels, temperatures up to 600 °C). However, ceramic coatings exposed to aggressive agents and thermal cycles can experience devitrification and spalling problems, with the consequent loss of their protective properties.The present study uses the electrochemical impedance spectroscopy technique to characterize, in a non-destructive way, the appearance of surface defects induced by the effect of temperature and chemical attack on a vitreous enamel deposited on steel. By means of analysis of the impedance diagrams obtained, a relationship is established between the loss of the coating's protective properties and the mechanism by which the corrosion process takes place.

The role of large rivers sustaining the civilizations across the world has long been debated. Mapping of palaeochannels using satellite images and the superimposition of known archaeological sites along them are often used as a strong piece of evidence to promote the so-called ‘river-culture’ hypothesis. The northwest India has been a hotbed of such studies where a large and wide trace of a palaeochannel (Ghaggar-Hakra channel) mapped from satellite images was linked to the Harappan Civilization, the demise of which was attributed to the decay of a large river (Sarasvati) that once flowed through the region. Recent research involving geophysical surveys and drilling and followed by the strong geochronological framework established the subsurface existence of these palaeochannels and their chrono-stratigraphic evolution. However, it was clearly demonstrated that this large palaeochannel was abandoned shortly after ~8 ka and much before the Harappan Civilization developed in this region (~4.6–3.9 ka). These findings strongly contested the contemporaneity of the large river with the Harappan Civilization and instead suggested river avulsion as a major factor for the onset and stabilization of the Harappan culture. Here, we extend this study to further east and examine the palaeochannels related to the Yamuna River that have also been considered to be important tributaries of the large Sarasvati River represented by the Ghaggar-Hakra palaeochannel. At least two of the palaeochannels of the Yamuna have been suggested to be connected to the Ghaggar-Hakra palaeochannel but very limited subsurface evidence exists till date to establish this. Here, we present new, high-resolution stratigraphic data based on vertical electrical resistivity soundings (1D–VES), multi-electrode electrical resistivity tomography (2D–ERT), and multi-probe well log surveys in one of the palaeochannels of the Yamuna to map the large-scale geometry and architecture of the valley fills of the palaeochannel system in the subsurface. The geophysical signatures recorded as VES on two transects trending NW–SE in Karnal and Kaithal districts of Haryana at 9 and 13 locations respectively, along with continuous ERT in selected transects reveal the presence of subsurface sand bodies (~10 to N30 m thick) interbedded with silty clay layers that are laterally stacked. The occurrence of thick and wide sand bodies having channel form geometry in the subsurface implies that these are the deposits of a large river system and suggests that the Yamuna was once connected to the palaeo-Ghaggar River as hypothesized by earlier workers based on remote sensing interpretations.

Telah di lakukan penelitian untuk memperoleh informasi mengenai posisi dan kondisi batuan dasar (bedrock) di sekitar gedung FMIPA Unsyiah, Darussalam, Banda Aceh dengan menggunakan metode resistivity (tahanan jenis). Hasil pengukuran yang di lakukan masing-masing dengan diterapkan konfigurasi Wenner-Schlumberger sebanyak 2 line, yaitu line 1 di samping Fakultas Kelautan dan Perikanan dan line 2 di depan Laboratorium MIPA di peroleh bahwa posisi batuan dasar (bedrock) berupa batuan granit. Lapisan bedrock berada pada kedalaman bervariasi antara 15 m – 40 m dengan nilai resistivitas berkisar antara 15000-100000 ohm-meter, dengan kepadatan yang cukup baik. Lapisan bedrock kedalamannya cenderung bertambah dari arah barat ke arah timur. Penelitian ini dapat bermanfaat dalam penentuan kedalaman pondasi untuk pembangunan gedung baru Fakultas MIPA Unsyiah.

Kata Kunci: Resistivity, Schlumberger, Wenner, Bedrock, FMIPA Unsyiah

Video presentation of Historical and archaeological investigations of 33Wo50 excavated in 1977 revealed the archaeological remains of the Amos Spafford Farm-House (1810-1812) at Port Miami, Michigan Territory. The house was plundered, burnt, and destroyed on August 21, 1812 by a party of British and Indians from Fort Malden, Canada. During this raid Shawnee chief Tecumseh led the Indians, while British Captain Peter Latouche Chambers, 41st Regiment of Foot led the British contingent.

Alternative semiconductor materials to copper indium gallium selenide (CIGS), copper zinc tin sulphide (CZTS), cadmium telluride
(CdTe) is driven by the need to use less toxic and earth-abundant materials as an absorber layer in thin film solar cells. The ternary compounds
based on Sn–Sb–S (TAS) compositions are deemed to be a possible replacement of existing semiconductor materials due to their
low processing cost and nontoxic elemental composition. In this study thin films of tin antimony sulphide (TAS) are deposited on glass
substrate from tin sulphide and antimony sulphide binary precursors, without substrate heating, combinatorially in thermal vacuum
chamber. The average thickness of the library obtained was 1.2 lm as measured by quartz crystal monitor. The X-ray diffraction analyses
measured by D-8 Discover diffractometer shows that the as deposited films were amorphous while the annealed films are poly crystalline.
The maximum reflection was observed for the lattice plane (111) for SnSb2S4 and Sn2Sb2S5. The optical properties of the thin films were
measured by ellipsometry while electrical properties were measured by photoconductivity spectrometer and four-probe technique. The
band gap was varied with variation in elemental composition as well as annealing temperature between 1.6 and 2.7 eV. It was observed
that TAS exhibit bipolar conductivity at different annealing temperature.