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The increase in electricity consumption by air conditioning equipment is a serious concern due to global environmental degradation resulting from greenhouse gas emissions. The present work aims to reduce power consumption and increase the energy efficiency of inverter-type split air conditioner (ISAC) by employing a direct evaporative cooler (DEC). The ambient temperature (24–43 °C), relative humidity (20–80%), cooling load (1580–5750 W), and evaporator temperature (3–12 °C) are the input parameters for the ISAC. The increased heat exchange between evaporatively cooled condenser and the ambient air helps to reduce the power input and improve energy efficiency ratio (EER). The Box–Behnken design (BBD) is used to predict the outputs by developing quadratic models and optimize the results. The analysis of variance (ANOVA) is performed for the statistical analyses of the model. The BBD indicates interaction of parameters, while ANOVA provides the fitness and validation of the model. DEC-ISAC decreases the power by 21.6% and improves EER by 23.7%, at 43 °C ambient temperature and 50% RH compared with the conventional ISAC. The minimized power and maximized EER values obtained by multi-objective optimization are 1087 W and 3.82 Wh/Wh, respectively, for the optimized input parameters (Ta= 34.5 °C, RH = 63.7%, Q˙L= 4186 W, and Te= 6.8 °C). The influence of ambient temperature is more significant than other input parameters. It is observed that DEC is highly effective for improving the efficiency of ISAC in high ambient temperature and low RH conditions. The payback period of the proposed system for optimized input parameters is estimated as 2.9 years.

The global increase in refrigeration and air conditioning applications poses a severe problem as regards the environmental degradation caused by greenhouse gas emissions. This study introduces a novel approach wherein both evaporative cooling and passive cooling are integrated to unveil notable enhancements in energy and exergy compared to conventional air conditioning systems. Therefore, this work aims to enhance the thermal performance of a 1.5-ton split air conditioner (SAC) employing outdoor (condenser) evaporative and indoor passive cooling (EPC). The heat removal capacity of a condenser and SAC performance are greatly affected by the air temperature at the condenser inlet. Evaporative cooling serves to lower outdoor air temperature, while passive cooling minimizes the indoor cooling load. Design parameters encompass outdoor temperature (Ta = 30–44 °C), relative humidity (RH = 20–80%), and temperature reduction due to passive cooling (ΔTR = 0.5–5 °C). A model is developed to calculate the temperature reductions of outdoor air through evaporative cooling in diverse climatic conditions, while the range of passive cooling degrees is obtained from previous experiments. Results indicate a substantial enhancement in the thermodynamic performance of the proposed system. The maximum coefficient of performance (COP) improvement of 68.66% is achieved at 44 °C outside temperature and 20% relative humidity. Annual energy savings, under extreme operating conditions, range from 358.4 kWh to 2116.8 kWh. The EPC SAC is identified as more sustainable than the conventional split air conditioner (CSAC). Moreover, the projected system is anticipated to recoup its costs within a relatively short period of 1.42 years.

The vapor-compression-based conventional split air conditioners (CACs) consume a large portion of total electrical power and pose an alarming threat to global environment. The present work aims to reduce cooling load and power consumption of CAC by employing a dew point evaporative cooler (DPEC). DPEC consists of a counter flow type heat and mass exchanger with alternate layers of dry and wet channels. The intake air is sensibly cooled before entering the cooling room through the evaporator coil of the air conditioner. Also, the working air (a part of outlet air in dry channel), after absorbing sensible heat of intake air and water vapors from the wet channel surface, is allowed to pass across the condenser coils. The intake dry-bulb temperature (T0 = 29–44 °C) and specific humidity (ω0 = 6–22 g/kg) are taken as input parameters. While the cooled air entering the evaporator decreases the cooling load on the conditioned space, the compression work is also reduced due to increased heat transfer in the condenser. The maximum reductions in cooling load and monthly energy consumption at T0 = 44 °C and ω0 = 6 g/kg are found as 59.54% and 340 kW h, respectively. The water consumption for different months of the cooling season varies from 1037.8 L to 2905.95 L. The average energy savings with the DPEC system for hot-dry climate (from April to June) and hot-humid climate (from July to September) of New Delhi, India, are observed to be 479.6 kW h and 79.1 kW h, respectively. The proposed system is found to payback in about 3.37 years.

The implementation of inlet air cooling in combined cycle gas turbine (CCGT) plant is imperative to mitigate the adverse consequences, such as reduced performance, caused by high ambient temperatures. Therefore, this paper presents a novel idea of integration of the CCGT plant and a double-effect water-LiBr vapor absorption refrigeration system for inlet air cooling. The absorption system utilizes the waste heat of CCGT exhaust gas to cool the ambient air at the compressor’s inlet. The objective of this paper is to compare the energy, exergy, and sustainability factors of an integrated system to that of the standalone CCGT plant. This novel approach has improved the thermodynamic performance and environmental sustainability of the integrated system. Subsequently, the energy analysis reveals that maximum improvements in work output and thermal efficiency of 5.04% and 1.64%, respectively, have been reported. Furthermore, the results show that as the ambient temperature rises, the work output of the standalone CCGT system decreases faster than that of the integrated CCGT system. Also, the integrated plant is more exergetically efficient. The maximum yield in exergetic efficiency and total work output is observed at the degrees of cooling of 8 K and 18 K, respectively. Therefore, this system can be operated suitably within this range of degrees of cooling. Besides, the exergy-based sustainability indicators are found to be improved. The environmental sustainability index has increased by up to 3.52%, showing improved fuel utilization. This also indicates that, for the same amount of emissions, the integrated CCGT plant generates more power.

Since the advent of human immunodeficiency virus infection, with its profound and progressive effect on the cellular immune system, a group of human opportunistic pathogens has come into prominence. Opportunistic [...]

This study was conducted to evaluate staining pattern of transferrin in benign and malignant lesion of breast. Sixty cases of breast lesions including 30 cases each of benign lesions and infiltrating ductal carcinoma breast formed the material for study. Immuno staining for transferrin was done by standard streptavidin biotin peroxidase method. Majority of benign lesions showed either negative or weak staining pattern while majority of malignant lesions gave consistent reaction with transferrin. Staining pattern of transferrin is more of prognostic significance in breast tumors than diagnostic value and may facilitate the decision making process in the treatment of individual cases of carcinoma breast. Keywords: Transferrin | breast, Introduction Breast lesions are broadly divided into three categories namely benign breast lesions, carcinoma in situ and carcinoma of breast. Benign breast lesions include three broad categories of lesions namely [...]

Table of Contents Abstract Introduction Case Reports Discussion References Abstract Calcifying epithelial odontogenic (Pindborg) tumour is a rare benign odontogenic neoplasm of unknown etiology. These are slow growing but locally [...]

Table of Contents Abstract Introduction Material and Methods Results Discussion References Abstract Breast carcinoma cells develop significant nuclear and cytoplasmic alterations during the development of this cancer through its various [...]

The professional personnel of a medical laboratory are bound by the ethical codes of their respective profession. Personnel responsible for the management of medical laboratories, as with other health professionals, [...]

Table of Contents Abstract Introduction Case Report Discussion References Abstract Primary cutaneous T-cell lymphoma is a rare condition representing 2% of all lymphomas. These represent a wide spectrum of disorders [...]

Model projections of future CO2and CH4exchange in Arctic tundra diverge widely. Here we used ecosysto examine how climate change will affect CO2and CH4exchange in troughs, rims, and centers of a coastal polygonal tundra landscape at Barrow, AK. The model was shown to simulate diurnal and seasonal variation in CO2and CH4fluxes associated with those in air and soil temperatures (Taand Ts) and soil water contents (θ) under current climate in 2014 and 2015. During RCP 8.5 climate change from 2015 to 2085, rising Ta, atmospheric CO2concentrations (Ca), and precipitation (P) increased net primary productivity (NPP) from 50–150 g C m-2y-1, consistent with current biometric estimates, to 200–250 g C m−2y−1. Concurrent increases in heterotrophic respiration (Rh) were slightly smaller, so that net CO2exchange rose from values of −25 (net emission) to +50 (net uptake) g C m−2y−1to ones of −10 to +65 g C m−2y−1. Increases in net CO2uptake were largely offset by increases in CH4emissions from 0–6 to 1–20 g C m−2y−1, reducing gains in net ecosystem productivity. These increases in net CO2uptake and CH4emissions were modeled with hydrological boundary conditions that were assumed not to change with climate. Both these increases were smaller if boundary conditions were gradually altered to increase landscape drainage during model runs with climate change. Permafrost thaw with climate change will raise NPP and Rhsimilarly in a coastal tundraPermafrost thaw with climate change will substantially raise CH4emissions in a coastal tundraThese increases in CH4emissions will be smaller if drainage increases with climate change

Abstract Objective-To develop and test a cardiac prevention and rehabilitation programme for achieving sustained lifestyle, risk factor, and therapeutic targets in patients presenting for the first time with exertional angina, [...]

The increasing usage of refrigeration and air conditioning worldwide is a serious concern as regard the greenhouse gas emissions which degrade the environment. Improving the energy efficiency could reduce this damage. The heat dissipation capacity of the condenser and performance of an air conditioner largely depend upon the temperature of the air entering the condenser. This paper evaluates the performance of a 1.5TR split air conditioner with and without evaporative cooling of condenser. The temperature reduction of the ambient air by evaporative cooling is computed for different weather conditions. The Box–Behnken design (BBD) methodology is applied to predict the interaction of parameters and optimize the results while analysis of variance (ANOVA) provides the fitness and validation of the model. It is observed that the proposed system significantly improves the performance of air conditioner. The maximum COP enhancement (9.37%) is achieved for the ambient temperature drop of 6.7 °C for the optimum operating conditions. The corresponding improvement in the refrigerating effect and savings in work input are obtained as 9.52% and 8.54%, respectively. The proposed system is estimated to pay back within 2.9 years. The sustainability indices indicate the environmental improvement by the proposed system.

The present work aims to investigate the effect of inlet air cooling in conjunction with other input parameters on the exergetic performance of combined cycle power plants (CCPP). To mitigate the adverse effects of high ambient temperature on performance, the CCPP has been equipped with an inlet air cooler, which lowers the air temperature at the inlet of the compressor. Under a specific combination of input parameters, the analysis revealed a maximum increase in net specific work, efficiency, and exergetic efficiency of 14.16%, 3.93%, and 5.65%, respectively. Moreover, the effects of multiple input parameters were analyzed individually and in combination. This was done in order to identify the most influential exergy-affecting parameters for the CCPP, which turned out to be the degree of cooling, pressure ratio, and turbine inlet temperature. The simulated model is then subjected to two sets of multi-objective optimization using a genetic algorithm, considering the above parameters as design variables. According to the Pareto set of optimal solutions, cooling the inlet air by 16.5 K results in the highest net-specific work output and increased exergy destruction. Increased exergy destruction, on the other hand, is undesirable. However, if the cost of power per unit is high, this could be economically advantageous.

Differences of surface elevation in arctic polygonal landforms cause spatial variation in soil water contents (θ), active layer depths (ALD), and thereby in CO2and CH4exchange. Here we test hypotheses in ecosysfor topographic controls on CO2and CH4exchange in trough, rim, and center features of low‐ and flat‐centered polygons (LCP and FCP) against chamber and eddy covariance (EC) measurements during 2013 at Barrow, Alaska. Larger CO2influxes and CH4effluxes were measured with chambers and modeled with ecosysin LCPs than in FCPs and in lower features (troughs) than in higher (rims) within LCPs and FCPs. Spatially aggregated CO2and CH4fluxes from ecosyswere significantly correlated with EC flux measurements. Lower features were modeled as C sinks (52–56 g C m−2yr−1) and CH4sources (4–6 g C m−2yr−1), and higher features as near C neutral (−2–15 g C m−2yr−1) and CH4neutral (0.0–0.1 g C m−2yr−1). Much of the spatial and temporal variations in CO2and CH4fluxes were modeled from topographic effects on water and snow movement and thereby on θ, ALD, and soil O2concentrations. Model results forced with meteorological data from 1981 to 2015 indicated increasing net primary productivity in higher features and CH4emissions in some lower and higher features since 2008, attributed mostly to recent rises in precipitation. Small‐scale variation in surface elevation causes large spatial variation of greenhouse gas (GHG) exchanges and therefore should be considered in estimates of GHG exchange in polygonal landscapes. Topographic effects on CO2fluxes caused lower features to be net C sinks and higher features to be near C neutralTopographic effects on CH4fluxes caused lower features to be larger CH4sources and higher features to be smaller CH4sourcesMuch of spatial and temporal variations in CO2and CH4fluxes were attributed in the model to topographic effects of water and snow movement

Abstract: Anisotropy of Magnetic Susceptibility (AMS) and seismic wave velocity studies of some paramagnetic Himalayan granitoids show good correlation between magnetic fabric anisotropy and P wave velocity (Vp). Vp shows strong positive correlation with magnetic lineation (L) and degree of magnetic anisotropy (P′) having correlation coefficient (r) values of 0.93 and 0.89 respectively. Both Vp and Vs show positive correlation with the SiO2 content of Proterozoic and Paleozoic granitoids. Velocity of S wave (Vs) shows negative correlation with mean magnetic susceptibility (Km) having ‘r’ value of 0.86. The correlation between Vs-Km, Vp-P′, Vp-L also shows >95% probability in Spearman’s rank correlation. Based on the results from the present sample size it is suggested that, in paramagnetic granites, Vp is proportional to intensity of deformation and preferred orientation of minerals as well as the mineralogy. On the other hand, Vs is more dependent on the mineralogy alone.

BackgroundTo analyze the spectrum of various types and subtypes of acute leukemia.MethodsTwo thousand five hundred and eleven consecutive new referral cases of acute leukemia AL were evaluated based on WHO classification.ResultsIt included 1,471 cases 58 of acute lymphoblastic leukemia ALL, 964 cases 38 of acute myeloid leukemia AML, 45 cases 1.8 of chronic myelogenous leukemia in blast crisis CMLBC, 37 cases 1.5 of biphenotypic acute leukemia BAL, 1 case of Triphenotypic AL, and 2 cases of acute undifferentiated leukemia AUL. Common subtypes of ALL were Bcell ALL 76, which comprised of intermediate stageCALLA positive 73, early precursorproBALL 3. Tcell ALL constituted 24 351 cases of ALL. Common subtypes of AML included AMLM2 27, AMLM5 15, AMLM0 12, AMLM1 12, APML 11, and AML t8;21 9. CMLBC was commonly of myeloid blast crisis subtype 40 cases.ConclusionBcell ALL was the commonest subtype in children and AML in adults. Overall incidence of AML in adults was low 53 only. CD13 was most sensitive and CD117 most specific for determining myeloid lineage. A minimal primary panel of nine antibodies consisting of three myeloid markers CD13, CD33, and CD117, Bcell lymphoid marker CD19, Tcell marker CD7, with CD45, CD10, CD34, and HLADR could assign lineage to 92 of AL. Cytogenetics findings lead to a change in the diagnostic subtype of myeloid malignancy in 38 1.5 cases. © 2008 Clinical Cytometry Society

The human immunodeficiency virus (HIV) epidemic is still in its early stages, and a marked increase in global prevalence is projected for the next coming years. Neither behavioural therapies nor current antiretroviral drugs are likely to have an impact on this silent epidemic. Current antiretroviral drugs are too expensive for the developing countries, and there are major problems of adherence, resistance and toxicity, which limit their application and efficacy. The main problem facing us, as inhabitants of a single world, is to prevent further infections regardless of where they occur, and this requires a vaccine programme. A successful immunotherapeutic HIV vaccine has the potential to overcome these problems, and would be a valuable advance. To accelerate the development of an HIV vaccine, additional candidate vaccines must be evaluated in parallel in both industrialized and developing countries. This will require international collaboration and coordination and critical ethical issues will need to be addressed. The probable triple cocktail of the future for global HIV prevention will be vaccination, anti-retroviral therapy, and not the least, behavioural therapy.

The f13 Coster–Kronig yield for Pb was determined as 0.60±0.03 using measured intensities of the Lα x-rays emitted following selective ionization in the L3 sub-shell by the Rb K x-rays (BL3 < Einc. < BL2) and of those emitted following ionization in the Li (i = 1, 2, 3) sub-shells by 59.54 keV γ-rays (BL1 < Einc. < BK), BK and BLi being the K shell and Li sub-shell ionization thresholds of Pb, respectively. The measurements were performed using a ²⁴¹Am annular source in direct excitation mode and in secondary excitation mode along with an RbNO3 secondary exciter as photon sources and an Si(Li) detector. Measurements of the f12 and f23 Coster–Kronig yields using similar experimental set-ups are also discussed. It is concluded that the f12 and f23 Coster–Kronig yields for 12 elements with 59 ≤ Z ≤ 90 measured by Oz et al. using a similar experimental set-up are not reliable. Copyright © 2002 John Wiley & Sons, Ltd.

The growth of Sb-based crystals (InSb, GaSb etc) was undertaken using resistive heater furnace by vertical directional solidification (VDS) technique. Crystal—melt interface shape during the growth was shown to convert from concave to convex along the crystal axis of the ingots. Many antimonide (Sb) crystals of 8 mm to 18 mm diameter were grown by optimized growth parameters. The forced convection and absence of conducting support to ampoule showed improvement in crystal quality of as grown ingots. Crystals showed preferred orientation and self-seeding. Results on interface shape and crystallinity of ingots were found to be in good agreement with the experiments.

We have studied interdiffusion processes occurring in a metal organic chemical vapour deposition (MOCVD) grown InP/In0.33Ga0.67As/InP/In0.33Ga0.67As/InP double quantum well structure through secondary ion mass spectrometry and high-resolution x-ray diffraction measurements along with a simulation programme. Results show an interdiffusion of phosphorus into the quantum wells and the presence of a 10 nm thick intermixed zone of In, As and P formed in-between the cap layer and the subsequent quantum well. Combination of these two techniques along with the simulation is a novel approach towards the understanding and quantification of in-depth compositional variation in thin films, in general. Copyright © 2000 John Wiley & Sons, Ltd.

Electrical characteristics of single crystal 〈100〉 orientation n-GaAs substrates implanted at room temperature with 100 MeV 28Si ions to a dose of 1 × 1014ions cm-2are reported. The room temperature electrical chracteristics of as-implanted samples and samples annealed in the temperature range of 100–1000 °C arc studied. The I–V curves show a complex behavior with annealing treatment. To understand this complex behavior, the resistance–temperature measurements for each annealing stage were carried out in the temperature range of 113 K–433 K. In the low temperature range from 113 K to 270 K, it is observed that the resistance of the as-implanted sample and samples annealed at and below 450 °C follows the relation $${\rho = \rho }_{0} {exp(}T_0 /T{)}^{{1/4}} $$ . This suggests that the conduction mechanism for these samples is governed by variable range hopping. In the high temperature range of 300 K to 433 K, it is observed that the resistance of samples annealed at 450–550 °C follows the relation $${\rho (}T{)} \cong {1/}T^{3/2} e^{\Delta E/kT} $$ which is characteristic of a conduction mechanism due to carriers in the extended states.

This paper investigates the options for a consumer to choose between different inverter and non-inverter type residential air conditioners (ACs) concerning their payback periods (PPs) and Life Cycle Cost (LCC) savings. The economics-based analysis carried out to evaluate the PPs by which the costs associated with owning and operating 3-star, 4-star, and 5-star inverter AC models are recoverable compared to non-inverter type (baseline model). The product costs (Cp), the repair costs (CR), the maintenance costs (CM), and the energy costs (CE) are taken as the decision parameters for evaluating the payback periods (PPs). It is shown that PPstrongly depends on the energy cost. Estimates of P P sare calculated as the futurs value of present cost involved in buying, maintaining, and running the ACs. It is concluded that inverter technology can save electrical energy by 12-22.4% compared to a non-inverter air conditioner. PPof 3-star inverter AC is estimated 2.17 years while P Pof 4-star and 5-star inverter ACs are 2.42 years and 2.33 years for 10 hours operation in a day when a higher slab of unit energy cost is considered. Depending on PPand daily usage requirements, a consumer can choose either a less efficient AC priced at a lower initial cost but more running cost or a more efficient AC priced at a higher initial cost but lesser running cost.

The results of an X‐ray reflectivity study of thick AlAs–AlGaAs and thin Ge–Si–Ge multilayers grown using metal‐organic vapour‐phase epitaxy and ion‐beam sputtering deposition techniques, respectively, are presented. Asymmetry in interfaces is observed in both of these semiconductor multilayers. It is also observed that although the Si‐on‐Ge interface is sharp, an Si0.4Ge0.6alloy is formed at the Ge‐on‐Si interface. In the case of the III‐V semiconductor, the AlAs‐on‐AlGaAs interface shows much greater roughness than that observed in the AlGaAs‐on‐AlAs interface. For thin multilayers it is demonstrated that the compositional profile as a function of depth can be obtained directly from the X‐ray reflectivity data.

With a view to investigating the aerobic and anaerobic proportions of oxygen supply during different grades of muscular activity in varying thermal stress, studies have been conducted on six young healthy Indians naturally acclimatized to heat. The subjects were given submaximal exercises of 400, 500, and 600 kgm/min (equivalent to 65.40, 81.75, and 98.10 W) for 6 min on a bicycle ergometer in three different simulated conditions, i.e., comfortable, hot humid, and very hot humid. Their O2 consumption (VO2), pulmonary ventilation (VE) and heart rate (HR) were measured during rest and throughout the exercise period (6 min) and for 30 min post exercise. Blood lactate level (LA) was measured during rest and recovery. From these, the total O2 cost with aerobic and anaerobic proportions were calculated. Results indicated a significant increase in the total O2 cost for each exercise with increasing thermal stress, along with a significant increase in the anaerobic fraction and a decrease in the aerobic fraction. The increase in anaerobic contribution to the energy supply processes was further confirmed by a significant increase in relative O2 debt (l/kg) and in blood lactate level at each work load. Thus, a highly significant correlation (P<0.001) was found between O2 debt contracted and increase in thermal stress. A significant fall in VO2 max was also observed in hot humid and very hot humid conditions as against comfortable temperature, with no change in HR max and VE max.

Abstract: Low pressure metalorganic vapor phase epitaxy grown strained InGaAs/GaAs quantum well structures have been characterized by photoluminescence and x-ray diffraction. It is shown that beyond the pseudomorphic limit, these structures show considerable gallium/indium interdiffusion at the interfaces and partial strain relaxation in the quantum well layers.

Abstract—Magnetovariational fields recorded by an array of magnetometers in the equatorial region of north-northeast Brazil are analyzed to infer the configuration of internal induced currents in and around the extensive intracratonic Parnaíba basin. Only nighttime magnetovariational fields were used because of the prevailing uniform source field conditions. For periods exceeding 40 min. the vertical fields at all inland sites are dominated by the effects of electric currents originating in the northeast, in the deep Atlantic Ocean. Below this period, although best developed in the 12–15 min. period range, the anomalous signatures are principally controlled by two distinct continental current paths. The first is associated with a N60°E trending graben-like structure in the southeastern part of the basin (named the Parnaíba Basin Conductivity Anomaly—PBCA) and the second appears as a subsurface sedimentary channel, from the NW corner of the array to the central part of the basin. This is named the LINK anomaly, as it connects the northwestern Marajó basin with the Parnaíba basin. While the PBCA is shown to highlight the importance of basement tectonics in the geological evolution of the Parnaíba basin, the LINK anomaly provides strong geophysical evidence of the direction of the sea intrusion into the region of the basin and possibly indicates the connectivity of the Parnaíba basin to the adjoining Amazon basin through the Marajó basin. Frequency and polarization dependence suggest that the induction response of individual structures is not determined by the local conductivity alone but also by their interconnectivity as well as by their linkage to the continental shelf and deep oceanic region.

Variations in ionic composition of the supporting media are crucial for the interpretation of phosphate sorption data. Four different supporting media (10-2 M CaCl2, 10-4 M CaCl2, 3 x 10-2 M NaCl, and 10-4 M NaCl) and soil solution composition determined separately for each soil in a 1:10 soil solution ratio were employed to study P sorption characteristics of arid and semiarid soils of Punjab. Phosphate sorption was the highest in 10-2 M CaCl2 and lowest in 10-4 M NaCl. At equivalent ionic strengths, the adsorption maxima in 3 × 10-2 M NaCl for different soils ranged from 47 to 66% of that observed with 10-2 M CaCl2. Higher magnitude of adsorption in 10-2 M CaCl2 solution eventually was due to an additional effect of Ca2+ on P sorption by alkaline soils. Phosphate sorption is overestimated in 10-2 M CaCl2 compared to that in soil solution composition. However, it is quite tedious and time consuming to determine soil solution in a laboratory. For routine estimation P sorption isotherms should preferably be determined in a supporting solution containing 3 to 4 mM Ca2+ L-1 instead of the more commonly used 10 mM CaCl2 solution for arid and semiarid soils of Punjab.

Dopant distribution, electrical activity and damage annealing of high-dose (∼5 × 1015 cm2) Ga-implanted silicon samples annealed by conventional thermal annealing have been studied by alpha particle back-scattering, differential Hall effect and ellipsometry measurements. Back-scattering spectra show that there is no long tail of Ga atoms in the as-implanted samples. Upon annealing these samples the damaged amorphous layer recrystallizes at about 570°C by solid phase epitaxy. During the epitaxial regrowth the dopant atom distribution seems to be modified. Further, very high levels of electrical activaton of Ga-atoms (∼3 × 1020 cm-3), much higher than the maximum solubility limit of Ga in Si (4.5 × 1019 cm-3), is achieved by thermal annealing of the sample at ∼570°C. This is comparable to the doping achieved by laser annealing of the Ga implanted Si. All the above three measurements show that there is residual damage in the high dose (≳1015cm-2) implanted samples after the recrystallization at about 570°C. This may be related to strain in the lattice at the high concentrations of metastable substitutional Ga atoms. Annealing at higher temperature reduces the electrical activity of Ga atoms, possibly by driving out the metastably high substitutional concentrations of Ga-atoms into electrically inactive clusters or precipitates.

We have used ion implantation of 30 keV48Ti+ ions into a-Si films at nominal doses of 1020-1021 ions/m2 to fabricate coherent silicide layers. Characterization of these layers and study of their annealing behaviour were carried out using XRD and RBS techniques. We find that the layers are a mixture of Ti5Si4, TiSi, TiSi2 and Si. On annealing at relatively lower temperatures (up to ∼ 300° C), predominant silicide phases present in the layer are Ti-rich, such as Ti5Si4 and TiSi. At higher temperatures, the Ti-rich layer has a tendency to consume unreacted Si from the film and to form a predominantly Si-rich silicide layer. A structure of silicon different from the diamond cubic structure is noticed in these implanted layers.

The magnetovariational response of a 2D electrical structure in the southeastern part of the Parnaíba basin, north-northeast Brazil, has been inverted in terms of laterally variable sheet current. The resulting inverted current distribution helps to visualize the overall basement configuration as a graben-horst-graben structure or alternatively indicates the presence of a resistive intrusive within a broad graben infilled with conductive sediments. Carbon bearing sediments are suggested as an alternative to hydrated sediments to account for the high conductivity of the mapped anomalies. Heating effects associated with the Cretaceous magmatic activity may be responsible in producing carbon through the pyrolysis of the hydrocarbon-saturated Paleozoic sediments or through the coalification of terrestrial plants.

The hydrated oxides which are formed by the addition of ammonium bi-carbonate to a solution of Zn(NO3)2 and Fe(NO3)3, and drying the precipitates at 110° are zinc hydroxy carbonate(I) and iron(III) oxide gel(II), respectively. A new, derived derivative thermogravimetric curve along with conventional DTA and DTG methods have been used to study the reaction between (I) and (II) in two components system.